Enhancing the occupational safety and well-being of mining and construction workers: an application of emotional intelligence training (EIT)Mukhtar Olalekan Iyanda, Blessing Olamide Taiwo, Yewuhalashet Fissha, Adams Abiodun Akinlabi, Kelebogile Phili, Hajime Ikeda, Youhei KawamuraSafety in Extreme Environments 2024年01月08日 Abstract The mining and construction sector in Nigeria holds a pivotal position in driving economic development; nonetheless, it encounters notable challenges, such as project failures and safety apprehensions. The impact of leadership and safety considerations encompasses a broad spectrum of outcomes for projects and the welfare of individuals. The primary aim of this study is to investigate the possibility of inducing significant changes by introducing emotional intelligence (EI) training in the mining and construction industries in Ogun State, Nigeria. The present study employed a mixed-methods research design to authenticate the significant enhancements in post-training emotional intelligence (EI) levels seen among personnel at New Creation Constructions Ltd. The study included the consideration of five distinct groups (A-E) that were responsible for managing comparable projects. The optimization of Group E’s improvement was achieved by the implementation of Emotional Intelligence (EI) training, and subsequently compared to the performance of the remaining four groups. The safety procedures within Group E experienced a substantial enhancement, marked by an escalated utilization of protective equipment, heightened consciousness of safety measures, and a reinforced dedication to safeguarding the welfare of colleagues. Group E exhibited outstanding project management efficiency, displaying commendable performance in multiple areas such as budget adherence, adherence to safety procedures, stakeholder satisfaction, effective communication, and proficient procurement management. To optimize the benefits outlined above, we suggest implementing emotional intelligence (EI) training programs, leadership development initiatives, stress management interventions, regular evaluations of well-being, and focused research tailored to the specific needs of the organization.
Urban Quarry Ground Vibration Forecasting: A Matrix Factorization ApproachHajime Ikeda, Masato Takeuchi, Elsa Pansilvania, Brian Bino Sinaice, Hisatoshi Toriya, Tsuyoshi Adachi, Youhei KawamuraApplied Sciences 13 23 12674 - 12674 2023年11月25日 Blasting is routinely carried out in urban quarry sites. Residents or houses around quarry sites are affected by the ground vibrations induced by blasting. Peak Particle Velocity (PPV) is used as a metric to measure ground vibration intensity. Therefore, many prediction models of PPV using experimental methods, statistical methods, and Artificial Neural Networks (ANNs) have been proposed to mitigate this effect. However, prediction models using experimental and statistical methods have a tendency of poor prediction accuracy. In addition, while prediction models using ANNs can produce a highly accurate prediction results, a large amount of measured data is necessarily collected. In an urban quarry site where the number of blastings is limited, it is difficult to collect a lot of measured data. In this study, a new PPV prediction method using Weighted Non-negative Matrix Factorization (WNMF) is proposed. WNMF is a method that approximates a non-negative matrix (including missing data) to the product of two low-dimensional matrices and predicts the missing data. In addition, WNMF is one of the unsupervised learning methods, so it can predict PPV regardless of the amount of data. In this study, PPV was predicted using measured data from 100 sites at the Mikurahana quarry site in Japan. As a result, the proposed method showed higher accuracy when using measured data at 60 sites rather than 100 sites, and the root mean square error for PPV prediction decreased from 0.1759 (100 points) to 0.1378 (60 points).
Deep Learning-Based Estimation of Muckpile Fragmentation Using Simulated 3D Point Cloud DataHajime Ikeda, Taiga Sato, Kohei Yoshino, Hisatoshi Toriya, Hyongdoo Jang, Tsuyoshi Adachi, Itaru Kitahara, Youhei KawamuraApplied Sciences (Switzerland) 13 19 2023年10月 This research introduces an innovative technique for estimating the particle size distribution of muckpiles, a determinant significantly affecting the efficiency of mining operations. By employing deep learning and simulation methodologies, this study enhances the precision and efficiency of these vital estimations. Utilizing photogrammetry from multi-view images, the 3D point cloud of a muckpile is meticulously reconstructed. Following this, the particle size distribution is estimated through deep learning methods. The point cloud is partitioned into various segments, and each segment’s distinguishing features are carefully extracted. A shared multilayer perceptron processes these features, outputting scores that, when consolidated, provide a comprehensive estimation of the particle size distribution. Addressing the prevalent issue of limited training data, this study utilizes simulation to generate muckpiles and consequently fabricates an expansive dataset. This dataset comprises 3D point clouds and corresponding particle size distributions. The combination of simulation and deep learning not only improves the accuracy of particle size distribution estimation but also significantly enhances the efficiency, thereby contributing substantially to mining operations.
Application of Bayesian Neural Network (BNN) for the Prediction of Blast-Induced Ground VibrationYewuhalashet Fissha, Hajime Ikeda, Hisatoshi Toriya, Tsuyoshi Adachi, Youhei KawamuraApplied Sciences (Switzerland) 13 5 2023年03月 Rock blasting is one of the most common and cost-effective excavation techniques. However, rock blasting has various negative environmental effects, such as air overpressure, fly rock, and ground vibration. Ground vibration is the most hazardous of these inevitable impacts since it has a negative impact not only on the environment of the surrounding area but also on the human population and the rock itself. The PPV is the most critical base parameter practice for understanding, evaluating, and predicting ground vibration in terms of vibration velocity. This study aims to predict the blast-induced ground vibration of the Mikurahana quarry, using Bayesian neural network (BNN) and four machine learning techniques, namely, gradient boosting, k-neighbors, decision tree, and random forest. The proposed models were developed using eight input parameters, one output, and one hundred blasting datasets. The assessment of the suitability of one model in comparison to the others was conducted by using different performance evaluation metrics, such as R, RMSE, and MSE. Hence, this study compared the performances of the BNN model with four machine learning regression analyses, and found that the result from the BNN was superior, with a lower error: R = 0.94, RMSE = 0.17, and MSE = 0.03. Finally, after the evaluation of the models, SHAP was performed to describe the importance of the models’ features and to avoid the black box issue.
A system of the granite weathering degree assessment using hyperspectral image and CNNJaewon Kim, Youhei Kawamura, Osamu Nishikawa, Brian Bino Sinaice, Natsuo Okada, Shinji UtsukiINTERNATIONAL JOURNAL OF MINING RECLAMATION AND ENVIRONMENT 36 5 368 - 380 2022年05月 Due to weathering processes that occur all around the world, rocks that are exposed eventually undergo physical and chemical changes. These weathering processes have the potential to turn fresh rocks into soft and weakened derivatives, leading to the collapse and subsidence of structures, such as tunnels, dams, and others, as well as natural structures, such as cliffs and slopes. This study attempts to employ hyperspectral imaging and a deep learning network called Convolutional Neural Network (CNN) in the effort to achieve a reliable process for rock weathering degree assessment. This study employs a hyperspectral image camera capable of detecting electromagnetic radiation from 400 nm-1000 nm with a spectral resolution of 204 bands. The CNN algorithm used in this study is based on a modified VGG-16 architecture. The total amount of data from granite samples employed amounts to 19,456 files. 80% of the total data were used as learning data and the remaining 20% as testing and validation data. The results show that the system has an average precision of over 94%. The study, therefore, concludes that the conjunction of hyperspectral imaging with CNN is a practicable process for the evaluation of the degree of weathering granite without the need for specialised human expertise or prejudice.
Use of a DNN-Based Image Translator with Edge Enhancement Technique to Estimate Correspondence between SAR and Optical ImagesHisatoshi Toriya, Ashraf Dewan, Hajime Ikeda, Narihiro Owada, Mahdi Saadat, Fumiaki Inagaki, Youhei Kawamura, Itaru KitaharaApplied Sciences (Switzerland) 12 9 2022年05月01日 In this paper, the local correspondence between synthetic aperture radar (SAR) images and optical images is proposed using an image feature-based keypoint-matching algorithm. To achieve accurate matching, common image features were obtained at the corresponding locations. Since the appearance of SAR and optical images is different, it was difficult to find similar features to account for geometric corrections. In this work, an image translator, which was built with a DNN (deep neural network) and trained by conditional generative adversarial networks (cGANs) with edge enhancement, was employed to find the corresponding locations between SAR and optical images. When using conventional cGANs, many blurs appear in the translated images and they degrade keypoint-matching accuracy. Therefore, a novel method applying an edge enhancement filter in the cGANs structure was proposed to find the corresponding points between SAR and optical images to accurately register images from different sensors. The results suggested that the proposed method could accurately estimate the corresponding points between SAR and optical images.
Spectral Angle Mapping and AI Methods Applied in Automatic Identification of Placer Deposit Magnetite Using Multispectral Camera Mounted on UAVBrian Bino Sinaice, Narihiro Owada, Hajime Ikeda, Hisatoshi Toriya, Zibisani Bagai, Elisha Shemang, Tsuyoshi Adachi, Youhei KawamuraMinerals 12 2 2022年02月 The use of drones in mining environments is one way in which data pertaining to the state of a site in various industries can be remotely collected. This paper proposes a combined system that employs a 6-bands multispectral image capturing camera mounted on an Unmanned Aerial Vehicle (UAV) drone, Spectral Angle Mapping (SAM), as well as Artificial Intelligence (AI). Depth possessing multispectral data were captured at different flight elevations. This was in an attempt to find the best elevation where remote identification of magnetite iron sands via the UAV drone specialized in collecting spectral information at a minimum accuracy of +/− 16 nm was possible. Data were analyzed via SAM to deduce the cosine similarity thresholds at each elevation. Using these thresholds, AI algorithms specialized in classifying imagery data were trained and tested to find the best performing model at classifying magnetite iron sand. Considering the post flight logs, the spatial area coverage of 338 m2, a global classification accuracy of 99.7%, as well the per-class precision of 99.4%, the 20 m flight elevation outputs presented the best performance ratios overall. Thus, the positive outputs of this study suggest viability in a variety of mining and mineral engineering practices.
Dimensional Reduction of Rock Hyperspectral Signatures and Classiflcation Based on a NCA Method used in developing a UAV Multispectral Imaging SystemBrian Bino Sinaice, Narihiro Owada, Hajime Ikeda, Hisatoshi Toriya, Elisha Shemang, Zibisani Biza Bagai, Shinji Utsuki, Tsuyoshi Adachi, Youhei KawamuraInternational Journal of the Society of Material Engineering for Resources 25 1 102 - 108 2022年 The adoption of hyperspectral imaging has had positive feedback in multiple industries, especially those heavily reliant on the visual analysis of subjects. Reasons for such are primarily due to the high accuracies achievable from processing high dimensional data. Nevertheless, hyperspectral data is said to possess a' dimensionality curse'. This phenomenon, deems it computationally demanding and difflcult to employ in rapid fleld investigations such as the use of drone-mounted spectral cameras to distinguish rocks. To counter this, this study proposes the employment of a method of reducing the number of dimensions used to highlight the most characteristic feature bands referred to as Neighbourhood Component Analysis(NCA). NCA aided in disregarding redundant bands from 204 dimensionalities, to a still highly capable 5 bands dimensionality, which coincides with the current production of 5-band detection drones. To process this data, several machine learning(ML) algorithms were run in order to perform spectral classiflcation of rocks based on the 5 NCA deflned bands. This study's novel flndings show that one is able to acquire with NCA and ML, 5 bands, with a post-optimization average global accuracy of 95.4%. Such capabilities are highly sufflcient considering the magnitude of the dimensionality reduction combined with the potential fleld drone applicability.
Deep Learning as an Early Detection System for Rotary Percussion Drilling MalfunctionsYoshino Kosugi, Hisatoshi Toriya, Mahdi Saadat, Tsuyoshi Adachi, Hajime Ikeda, Youhei KawamuraInternational Journal of the Society of Material Engineering for Resources 25 2 205 - 211 2022年 To mine in the underground, the method of blasting and blast hole drilling methods are mainly, and widely accepted. The hole drilling methods are done with rotary percussion drill. However, there are problems in terms of diffi culty of operating and mining cost resulting from its failure occurs, and thus it is hard for mining companies to fi nd a way of mining underground effi ciently, profi tability, and safely. From this background, it is necessary to build the early detection system for drill bit failure. This system needs the technology of CNN (Convolutional Neural Network Smart Mining, which is the process of using information, autonomy, and technology to improve safety, reduce operating costs, and improve mine site productivity. In this research, drilling vibration from rotary percussion drill is transmitted as acceleration waveform and used as input data for building the system. The data is collected replacing the kinds of diameter of bit or drilling condition. This data is for developing the model introduced CNN to detect the difference between Normal drilling and the other kinds of drilling with something error. For Firstly, batch of waveform data is input model as training data to make the model recognize the data pattern. Secondly, validation process confi rms the correct answer rate against the training data, and then, the test for the model is practiced. Finally, by comparing each accuracy in phase of test from 4 types of models built with diff erent kinds of data and the ideal way of the input waveform data is found.
Communication Experiment of Wi-Fi Direct for Underground Mine Environment Visualization SystemHajime Ikeda, Youhei Kawamura, Oluwafemi Kolade, Daniyar Malgazhdar, Mahdi Saadat, Fumiaki Inagaki, Hisatoshi Toriya, Frederick Thomas CawoodLecture Notes in Civil Engineering 228 65 - 76 2022年 One of the main problems in the modern metal mining sector is the depletion of near-surface deposits, the decline in grades. Available deposits near to surface are available and the focus of the industry is shift to deep underground deposits. However, with increase in mining depth risk of rock falls and rock bursts increases concurrently. In order to solve these problems, “smart mining” technology has been introduced. “Smart mining” is an area that combines ICT and intelligent resource development. We have developed a communication system that plays a fundamental role in this field, and have conducted communication tests. Communication systems in underground mines are essential for better safety and productivity. In this research, wireless sensor networks (WSNs) have been proposed to record and transfer environmental and worker position data. This research proposes a communication system using “Wi-Fi Direct”, in which data loggers and mobile terminals (i.e., smartphones) transfer data between nodes. According to the technology, data is transmitted from a fixed underground base unit to a worker’s mobile terminal. Next, these datasets transferred to a data logger on surface once the worker gets close enough, the data transmitted wirelessly between surface and underground locations. To verify the feasibility of this system, the communication range, transfer speed, and received signal strength indicator (RSSI) in different environments were measured.
Model Scaling in Smartphone GNSS-Aided Photogrammetry for Fragmentation Size Distribution EstimationZedrick Paul L. Tungol, Hisatoshi Toriya, Narihiro Owada, Itaru Kitahara, Fumiaki Inagaki, Mahdi Saadat, Hyong Doo Jang, Youhei KawamuraMINERALS 11 12 2021年12月 Fragmentation size distribution estimation is a critical process in mining operations that employ blasting. In this study, we aim to create a low-cost, efficient system for producing a scaled 3D model without the use of ground truth data, such as GCPs (Ground Control Points), for the purpose of improving fragmentation size distribution measurement using GNSS (Global Navigation Satellite System)-aided photogrammetry. However, the inherent error of GNSS data inhibits a straight-forward application in Structure-from-Motion (SfM). To overcome this, the study proposes that, by increasing the number of photos used in the SfM process, the scale error brought about by the GNSS error will proportionally decrease. Experiments indicated that constraining camera positions to locations, relative or otherwise, improved the accuracy of the generated 3D model. In further experiments, the results showed that the scale error decreased when more images from the same dataset were used. The proposed method is practical and easy to transport as it only requires a smartphone and, optionally, a separate camera. In conclusion, with some modifications to the workflow, technique, and equipment, a muckpile can be accurately recreated in scale in the digital world with the use of positional data.
Coupling NCA Dimensionality Reduction with Machine Learning in Multispectral Rock Classification ProblemsBrian Bino Sinaice, Narihiro Owada, Mahdi Saadat, Hisatoshi Toriya, Fumiaki Inagaki, Zibisani Bagai, Youhei KawamuraMINERALS 11 8 2021年08月 Though multitudes of industries depend on the mining industry for resources, this industry has taken hits in terms of declining mineral ore grades and its current use of traditional, time-consuming and computationally costly rock and mineral identification methods. Therefore, this paper proposes integrating Hyperspectral Imaging, Neighbourhood Component Analysis (NCA) and Machine Learning (ML) as a combined system that can identify rocks and minerals. Modestly put, hyperspectral imaging gathers electromagnetic signatures of the rocks in hundreds of spectral bands. However, this data suffers from what is termed the 'dimensionality curse', which led to our employment of NCA as a dimensionality reduction technique. NCA, in turn, highlights the most discriminant feature bands, number of which being dependent on the intended application(s) of this system. Our envisioned application is rock and mineral classification via unmanned aerial vehicle (UAV) drone technology. In this study, we performed a 204-hyperspectral to 5-band multispectral reduction, because current production drones are limited to five multispectral bands sensors. Based on these bands, we applied ML to identify and classify rocks, thereby proving our hypothesis, reducing computational costs, attaining an ML classification accuracy of 71%, and demonstrating the potential mining industry optimisations attainable through this integrated system.
Tourist Participation in the Preservation of World Heritage - A Study at in Cambodia -Fumiya Kimura, Yutaka Ito, Toshiya Matsui, Hidehiko Shishido, Itaru Kitahara, Youhei Kawamura, Atsuyuki MorishimaJOURNAL OF CULTURAL HERITAGE 50 163 - 170 2021年07月 World Heritage Sites (WHSs) face several problems, such as increased maintenance costs, difficulties in checking protection conditions, and graffiti destruction by tourists. Hence, constructing a new system that can effectively lighten the burden of maintenance expenditures is necessary. Presently, a new preservation system that leverages Information and Communication Technology, 3D Restoration Technology by photographic data collection, and artificial intelligence and that involves tourists' participation has been developed. This paper aims to introduce the new preservation system, investigate the possibility of tourists cooperating with the system free of charge, and introduce the details and results of a choice experiment conducted on tourists at Bayon Temple in Cambodia. Analysis results showed that approximately 50% of respondents would be willing to cooperate free of charge, and statistical significance for certain attributes and interactions. The analysis indicated that providing appropriate incentives to tourists who have specific individual characteristics would help promote the use of the preservation system. (c) 2021 Elsevier Masson SAS. All rights reserved.
Investigating asperity damage of natural rock joints in polycrystalline rocks under confining pressure using grain-based modelMahdi Saadat, Abbas Taheri, Youhei KawamuraCOMPUTERS AND GEOTECHNICS 135 104144 - 104144 2021年07月 [査読有り][通常論文] A cohesive grain-based model (GBM) was employed to investigate the asperity damage response of jointed Aue granite under confined compression. The cohesive GBM was able to characterise both inter- and intra-grain contacts in distinct element method (DEM). We calibrated the model against the laboratory data, including confined and unconfined compression tests as well as Brazilian tensile test of Aue granite. We generated synthetic Aue granite specimens, including three different rock joint profiles with various joint roughness coefficients (JRC) from smooth to very rough (i.e. 4.6, 10.2, and 17.5). We conducted confined compression tests on the synthetic specimens under 2, 5, 10, and 40 MPa of confining pressures. The numerical results revealed that at high confining pressure (i.e. 40 MPa), the rock joint profile had a negligible influence of the damage response of the specimen, and only contributed to the reduction of strength. For the other numerical experiments, the intensity of asperity damage caused by grain crushing was more pronounced when the confining pressure was high. We concluded that the cohesive GBM framework has the potential to be used as a virtual laboratory for investigating the shear behaviour of jointed granitic rocks, which is challenging to be studied in the laboratory.
Incorporating asperity strength into rock joint constitutive model for approximating asperity damage: An insight from DEM modellingMahdi Saadat, Abbas Taheri, Youhei KawamuraENGINEERING FRACTURE MECHANICS 248 107744 - 107744 2021年05月 [査読有り][通常論文] This paper presents a DEM experiment for developing a rock joint constitutive model that is able to consider lab-scale geometrical parameters of waviness and unevenness. We carried out a systematic parametric study using DEM framework to investigate the influence of asperity area and asperity angle on the peak shear strength and peak dilation angle. Based on the insights obtained from numerical outputs, we defined an asperity strength parameter that was incorporated into the failure criterion of the rock joint model. We defined an asperity damage function to characterise the degradation of asperity strength parameter. Besides, we developed a separate damage function to consider the deterioration of frictional components of rock joints. Also, we augmented the dilative response of the rock joint model by defining a new dilation predictor that mimics the normal displacement with respect to the progressive shear displacement of the rock joint. The damage function was linked to plastic displacement of rock joint in all damage functions. We compared the model outputs with the results of experimental direct shear tests conducted on natural rock joints and observed a good agreement.
選鉱プロセスにおけるハイパースペクトルイメージングと深層学習を用いたヒ素含有鉱石の分類岡田 夏男, 前川 陽平, 大和田 済熙, 芳賀 一寿, 柴山 敦, 川村 洋平資源と素材 137 1 1 - 9 一般社団法人 資源・素材学会 2021年01月31日 [査読無し] Currently, there have been issues concerning the depletion and scarcity of mineral resources. This is mostly due to the excavation of high grade minerals having already occurred years and years ago, hence forcing the mining industry to opt for the production and optimization of lower grade minerals. This however brings about a plethora of problems, many of which economic, stemming from the purification of those low grade minerals in various stages required for mineral processing. In order to reduce costs and aid in the optimization of the mining stream, this study, introduces an automatic mineral identification system which combines the predictive abilities of deep learning with the excellent resolution of hyperspectral imaging, for pre-stage of mineral processing. These technologies were used to identify and classify high grade arsenic (As) bearing minerals from their low grade mineral counterparts non-destructively. Most of this ability to perform such tasks comes from the highly versatile machine learning model which employs deep learning as a means to classify minerals for mineral processing. Experimental results supported this statement as the model was able to achieve an over 90% accuracy in the prediction of As-bearing minerals, hence, one could conclude that this system has the potential to be employed in the mining industry as it achieves modern day system requirements such as high accuracy, speed, economic, userfriendly and automatic mineral identification.
Application of entropy method for estimating factor weights in mining-method selection for development of novel mining-method selection systemElsa Pansilvania Andre Manjate, Mahdi Saadat, Hisatoshi Toriya, Fumiaki Inagaki, Youhei KawamuraJournal of Sustainable Mining 20 4 296 - 308 2021年 Mining-method selection (MMS) is one of the most critical and complex decision-making processes in mine planning. Therefore, it has been a subject of several studies for many years culminating with the development of different systems. However, there is still more to be done to improve and/or create more efficient systems and deal with the complexity caused by many influencing factors. This study introduces the application of the entropy method for feature selection, i.e., select the most critical factors in MMS. The entropy method is applied to assess the relative importance of the factors influencing MMS by estimating their objective weights to then select the most critical. Based on the results, ore strength, host-rock strength, thickness, shape, dip, ore uniformity, mining costs, and dilution were identified as the most critical factors. This study adopts the entropy method in the data preparation step (i.e., feature selection) for developing a novel-MMS system that employs recommendation system technologies. The most critical factors will be used as main variables to create the dataset to serve as a basis for developing the model for the novel-MMS system. This study is a key step to optimize the performance of the model.
Hazard mapping of ground subsidence in east area of Sapporo using frequency ratio model and GISTaeyoo Na, Youhei Kawamura, Seong-seung Kang, Shinji UtsukiGEOMATICS NATURAL HAZARDS & RISK 12 1 347 - 362 2021年01月01日 [査読有り][通常論文] As an earthquake occurred in Iburi subprefecture, Japan on September 2018, Sapporo has also been damaged by ground subsidence. Ground subsidence can occur in various area, especially in urban areas causing considerable damage to human lives and properties. Currently, ground subsidence is one of the most important problems all over the world. However, quantitative research about ground subsidence due to earthquake that particularly occurred in urban area was not well studied. To prevent and minimize critical damage caused by subsidence, this study aims to construct hazard map to predict susceptible subsidence place in East area of Sapporo, using geographic information system (GIS) and frequency ratio (FR) model. To determine major factors related to ground subsidence, spatial databases were constructed from geological map, slope data, land use map, borehole data, precipitation data, railroad and subway line data and earthquake information data. Weight of each factors were estimated by FR model to analyze degree of subsidence hazard and construct subsidence hazard map. Constructed subsidence susceptibility map was compared with reported actual ground subsidence area for verification and showed prediction accuracy of 85.17%. This result showed sufficient possibility for reliable susceptibility mapping of ground subsidence using GIS and FR model.
Automated Identification of Mineral Types and Grain Size Using Hyperspectral Imaging and Deep Learning for Mineral ProcessingNatsuo Okada, Yohei Maekawa, Narihiro Owada, Kazutoshi Haga, Atsushi Shibayama, Youhei KawamuraMINERALS 10 9 1 - 22 2020年09月 In mining operations, an ore is separated into its constituents through mineral processing methods, such as flotation. Identifying the type of minerals contained in the ore in advance aids greatly in performing faster and more efficient mineral processing. The human eye can recognize visual information in three wavelength regions: red, green, and blue. With hyperspectral imaging, high resolution spectral data that contains information from the visible light wavelength region to the near infrared region can be obtained. Using deep learning, the features of the hyperspectral data can be extracted and learned, and the spectral pattern that is unique to each mineral can be identified and analyzed. In this paper, we propose an automatic mineral identification system that can identify mineral types before the mineral processing stage by combining hyperspectral imaging and deep learning. By using this technique, it is possible to quickly identify the types of minerals contained in rocks using a non-destructive method. As a result of experimentation, the identification accuracy of the minerals that underwent deep learning on the red, green, and blue (RGB) image of the mineral was approximately 30%, while the result of the hyperspectral data analysis using deep learning identified the mineral species with a high accuracy of over 90%.
Enhancement of bitumen recovery from the oil sand in an alkaline solution using ultrasound irradiation and carbon dioxideHirokazu Okawa, Tomonao Saito, Shohei Yasuda, Youhei Kawamura, Takahiro Kato, Katsuyasu Sugawara, Tayfun BabadagliJAPANESE JOURNAL OF APPLIED PHYSICS 59 SK 2020年07月01日 [査読有り][通常論文] Herein, we demonstrated the enhancement of bitumen recovery from the oil sand in a concentrated alkaline solution using ultrasound irradiation and carbon dioxide. The alkaline solution allowed the separation of bitumen and sand; however, it was difficult to collect bitumen via aeration. CO exhibited a high contact angle for bitumen even at a high pH. Therefore, we attempted to use CO for bitumen recovery under ultrasound irradiation, increasing the number of collisions between bitumen and the CO bubbles; thus, the bitumen recovery ratio exhibited a high value of approximately 70% even at a low CO injection rate of 20 ml min 2 2 2 2 -1
Accurate Overlapping Method of Ultra-Long Interval Time-Lapse Images for World Heritage Site InvestigationHidehiko Shishido, Emi Kawasaki, Youhei Kawamura, Toshiya Matsui, Itaru KitaharaACM JOURNAL ON COMPUTING AND CULTURAL HERITAGE 13 2 10 - 18 2020年06月 In this article, a method is proposed to accurately overlap multiple high-quality images with different shooting positions and intervals by combining corresponding point information between images and 3D shape information. In the proposed method, the correct feature matching of images obtained by rendering the 3D model of the subject is used. In this research, the subjects were the pillars of the Angkor Thom Bayon Temple and the epilithic microorganisms adhering to and eroding their surfaces. Synthetic transformation of a homography utilizing the correct matches is employed to overlap the target images. When overlapping different background images using the conventional method, estimation of the homography matrix becomes difficult owing to incorrect matches; thus, high-quality overlapping images cannot be obtained. The objective of this research was to realize the overlapping image process even under conditions that cause incorrect feature matches, such as differences in background and illumination. In this study, the damaged parts of the pillar surfaces were visualized using the proposed method. Based on the results of an experiment comparing the proposed method with an existing state-of-the-art method, the effectiveness and higher accuracy of the proposed method were verified. The findings of this research contribute to Angkor Thom Bayon Temple preservation, including a preservation project that the present authors are organizing for this culturally and historically valuable United Nations Educational, Scientific and Cultural Organization World Heritage site.
Development of 3D rock fragmentation measurement system using photogrammetryHyongdoo Jang, Itaru Kitahara, Youhei Kawamura, Yasunori Endo, Erkan Topal, Ryo Degawa, Samson MazaraINTERNATIONAL JOURNAL OF MINING RECLAMATION AND ENVIRONMENT 34 4 294 - 305 2020年04月 [査読有り][通常論文] Run-of-mine fragmentation is an important aspect of mine productivity optimisation, as it affects all mine-to-mill processes. In this study, a 3D rock fragmentation measurement (3DFM) system is proposed that can surmount the limitations of conventional 2D photo-based rock fragmentation measurement methods. To validate the proposed 3DFM performance, a laboratory-based comparison study was conducted using 100 randomly collected rock fragments. Conventional method exhibits relatively low and diffused results than the 3DFM. The proposed 3DFM can be considered as a new particle size distribution measurement method that should efficiently aid in improving mine productivity.
University Students' Preferences for Labour Conditions at a Mining Site: Evidence from Two Australian UniversitiesYutaka Ito, Shuto Mikami, Hyongdoo Jang, Abbas Taheri, Kenta Tanaka, Youhei KawamuraRESOURCES-BASEL 9 3 2020年03月01日 The mining industry makes up a large portion of the gross domestic product (GDP) in Australia, although securing human resources remains a problem in that field. The aim of this paper is to identify Australian university mining students' preferences, considering it as potential employees' preferences, for labour conditions at mining sites by means of a discrete choice experiment to promote efficient improvements in labour conditions in the mining industry. The data of 93 respondents analysed in this paper was collected by survey carried out in two universities in Australia. The result of the study showed that students have preferences on several factors such as wage, fatality rate, working position, commuting style, and company. Students having specific sociodemographic characters were found to show specific preferences on labour conditions. The results of this study indicate the potential average of appropriate monetary compensation for each factor.
Application of deep learning approaches in igneous rock hyperspectral imagingBrian Bino Sinaice, Youhei Kawamura, Jaewon Kim, Natsuo Okada, Itaru Kitahara, Hyongdoo JangSpringer Series in Geomechanics and Geoengineering 228 - 235 2020年 Hyperspectral imaging has been applied in remote sensing amongst other disciplines, success in these has triggered its extensive use. Hence, it comes as no surprise that we took advantage of this technology by conducting a study aimed at the spectral analysis of several igneous rocks, and to deduce the spectral signatures of each rock unit using neural networks. Through visual observations and comparisons of these spectral signatures, parameters such as band curvature(shape), tilt(position) and strength were used for lithological discrimination. Even with this said, there often exists similarities in rocks, which are rather difficult to differentiate by means of visual or graphical analysis. However, with numerous technologies making new waves in today’s era and artificial intelligence (AI) being at the forefront of these developments, it was best fitting to employ deep learning, often referred to as a subset of AI; to train/learn from these hyperspectral signatures with a goal aimed at classifying these rocks. Deep learning has networks such as the convolution neural network (CNN), which has algorithms that excel in feature representation from visual imagery; taking into account that the more data is fed into the training process and later used as a database for further training, the higher the future prediction accuracy. Gathered outcomes from the CNN show exceptionally high prediction accuracy capabilities of 96%; suggesting viable field and laboratory usage of these systems as a unit for mining and rock engineering applications.
Development of an underground in-situ stress monitoring system for mining safety using multi sensor cell and wi-fi direct technologyHajime Ikeda, Youhei Kawamura, Hyongdoo Jang, Nur Ellisha Binti Mokhtar, Jun Yokokura, Zedrick Paul L. TungolSpringer Series in Geomechanics and Geoengineering 236 - 244 2020年 The increasing global demand for minerals contributes to the necessity of mineral extraction at greater depths. However, the increase of rock in-situ stress with depth leads to higher risk and increasingly dangerous working conditions faced by mining workers. The presence of shafts, tunnels and other excavations necessary in mine expansions further increase the complexity of underground mines. This complexity of underground stress conditions increases the importance of monitoring and analysis of underground strata conditions, as early detection is crucial in the prevention of rock failure and the occurrence of fatal accidents. A better comprehension of the underground stress conditions in a mine is vital in considering mine design and supports that need to be installed. The development of an efficient monitoring system that can obtain and transmit data is necessary. This paper suggests the utilisation of a multi sensor cell that combines the functions of an accelerometer, gyroscope and a magnetometer, as well as strain gauge displacements to continuously measure the stress conditions of bedrock. The obtained data is then conveyed to the surface using a Wi-Fi Direct communication system and analysed to comprehend the changes in the underground stress conditions. The latter part of this paper also describes the experiments conducted to verify the ability of the proposed monitoring system.
An automated underground space monitoring and communication system based on wireless sensor networksMohammad Ali Moridi, Mostafa Sharifzadeh, Hyongdoo Jang, Youhei KawamuraSpringer Series in Geomechanics and Geoengineering 255 - 261 2020年 In the challenging environment and Cutting-edge technology in mining industry, reliable and effective communication is a high-stake issue, along with the objectives of safe and efficient underground mining operations. Automation through remote and automatic systems has delivered improvements in workplace health and safety for employees, operational management, energy and cost-effectiveness, and real-time response to events. In this context, Wireless Sensor Networks (WSNs) have been widely employed in underground monitoring and communication systems for the purpose of environmental monitoring, the positioning of workers and equipment, operational monitoring and communication system. Considering the capabilities of WSNs, a ZigBee network is adopted in this study. The aim of this study is to propose a reliable and effective monitoring and communication system in underground environments, using WSN nodes were developed to sense environmental attributes and texting emergency messages. A trigger action plan for monitored attributes above normal and threshold value limits is programmed in the surface GIS management server. The system will provide multi-users surface operation and 3D visualization for realistic understanding of underground environment and miners’ conditions.
Illumination of contributing parameters of uneven break in narrow vein mineHyongdoo Jang, Sina Taheri, Erkan Topal, Youhei KawamuraSpringer Series in Geomechanics and Geoengineering 457 - 466 2020年 One of the principal challenge facing the stope production in underground mining is the overbreak and underbreak (UB: uneven break). Although the UB features a critical economic fallout to the entire mining process, it is much inevitable and usually left as an unpredictable phenomenon in underground mines. The complex mechanism of UB must be examined to minimize the UB phenomenon. In this study, the contribution of ten primary UB causative parameters is scrutinized investigating a published UB prediction ANN model. The inputs (UB causative factors) contributions to the output (percentage of UB) of the ANN model were analyzed using Profile methodology (PM). The results PM revealed the essential importance of geological parameters to UB phenomenon as the calculated contributions of adjusted Q-rate (GAQ) and average horizontal to vertical stress ratio (GSK) are 20.48% and 18.12% respectively. Also, the trends of the other eight UB causative factors were investigated. The findings of this study can be used as a reference in stope design and reconciliation processes to maximize the productivity of the underground mine.
Clustering method of 3D point cloud of muck-pile based on connectivity of adjacent surfaceHidehiko Shishido, Zha Wanzhi, Hyongdoo Jang, Youhei Kawamura, Yoshinari Kameda, Itaru Kitahara2019 IEEE 8th Global Conference on Consumer Electronics, GCCE 2019 770 - 774 2019年10月 This paper proposes a method to measure the fragmentation distribution of a pile of rocks (muck-pile) using image-based 3D reconstruction. One of the most important aspects of mine-blasting is appropriate rock fragmentation to optimize the cost of the blasting operation. The conventional method of measuring fragmentation distribution is based on 2D image processing including segmentation of muck-pile regions into rock clusters. However, in the 2D method, the measurement accuracy is limited. To accurately measure rock fragmentation distribution, we reconstructed a 3D model of a muck-pile from multi-view images and segment the 3D model based on rock-features such as color, normal vector, distance and adjacent angles of surface planes. As a result, the size of each rock was calculated by fitting a bounding box. Based on experimental evaluations, it was confirmed that the accuracy of the proposed method is higher than that of previous methods.
An empirical approach of overbreak resistance factor for tunnel blastingHyongdoo Jang, Youhei Kawamura, Utsuki ShinjiTUNNELLING AND UNDERGROUND SPACE TECHNOLOGY 92 2019年10月 [査読有り][通常論文] The assessment of overbreak is proposed by means of a novel empirical approach; the ‘overbreak resistance factor’ (ORF), to predict and manage the overbreak phenomenon in tunnel drill-and-blast operations. The proposed ORF is formulated by analysing the relationship between uncontrollable parameters of the overbreak phenomenon, i.e., geological parameters, and the corresponding overbreak measurements. Ninety data sets were collected from the Shin-Hakoishi Tunnel operation in Japan. Initially, an identical weight was applied to all geological parameters to generate ORF subfactors. The contribution of these subfactors to the measured overbreak was analysed through the use of five overbreak prediction artificial neuron network (ANN) models. A sensitivity analysis was conducted on the ANN models to reveal the contributions of input factors to measured overbreak. The discontinuities factors demonstrated the highest influence on overbreak with an overall sensitivity of 55.20%, whereas the strength factors, the weathering factors and the face condition factors showed less sensitivity, at 27.18%, 9.43%, and 8.18% respectively. The sensitivity analysis results were applied back to the initial unweighted data sets to generate a weighted record of subfactors. The ORF values showed a clear inverse proportional relation to the measured overbreak values, through linear regression analysis. Consequently, a five-step ORF prediction chart was developed, which can be directly applied to estimate overbreak in any drill-and-blast tunnel project.
Implementation and Verification of a Wi-Fi Ad Hoc Communication System in an Underground Mine EnvironmentH. Ikeda, Y. Kawamura, Z. P.L. Tungol, M. A. Moridi, H. JangJournal of Mining Science 55 3 505 - 514 2019年05月01日 Wireless sensor networks WI-Fi ad hoc have been proposed information transmission between data loggers and mobile station (smartphones). The wireless data transmission follows from an underground station to a worker’s smartphone and, then, after the worker has left the mine, to a data logger on the surface. The serviceability of this system was tested by measurement of communication quality indexes in various environments. The tests show that wireless communication between a stationary point and a mobile devise is possible at transfer speeds up to 2 MB/s with a packet error rate (PER) below 25% either at a maximum distance of 110 m in a straight path or at a distance of 20 m in case of a corner or turn of the path. The proposed system allows the transmission of 39.6–79.2 MB of monitoring data to a worker moving at 20 km/h.
Development of wireless sensor networks for underground communication and monitoring systems (the cases of underground mine environments)Mohammad Ali Moridi, Mostafa Sharifzadeh, Youhei Kawamura, Hyong Doo JangTUNNELLING AND UNDERGROUND SPACE TECHNOLOGY 73 127 - 138 2018年03月 [査読有り][通常論文] The challenges of maintaining safe workplaces and improving operations and services in underground mines are unique. These have largely been mitigated by implementing new technology of wireless sensor networks (WSNs) in the last few years. Establishment and development of a reliable monitoring and communication network through such hostile environments are still major concerns. In this study, a more comprehensive monitoring and communication system for underground mine environments using ZigBee network are developed. To this regard, experiments with real systems and prototypes are applied. The controllable and uncontrollable parameters of both underground environment and network for the establishment of ZigBee network are also assessed. Then, a practical method to design a model of an underground mine monitoring and communication system is proposed. This model was verified by testing system functions and applications for example, temperature, humidity and illumination readings, text messaging, and controlling ventilation fans throughout an underground mine in Western Australia. The monitoring and communication systems operated successfully and it demonstrated the reliable outcomes of their function and application for underground mines.
Performance analysis of ZigBee network topologies for underground space monitoring and communication systemsMohammad Ali Moridi, Youhei Kawamura, Mostafa Sharifzadeh, Emmanuel Knox Chanda, Markus Wagner, Hirokazu OkawaTUNNELLING AND UNDERGROUND SPACE TECHNOLOGY 71 201 - 209 2018年01月 [査読有り][通常論文] The advancement in tunnelling and underground space technologies and the need for large scale monitoring and communication systems for safe and efficient operations has triggered the era of wireless sensor networks (WSNs). The progress of WSNs have been associated with the innovation of sensor nodes with the more significant features of smaller size, more cost-effectiveness, lower latency and powerful antenna coverage. The sensor nodes arrangement in dense industrial WSNs is one of the crucial issues for a better quality of service and a reliable message transmission through the network. In this study, we investigate various sensor node arrangements of ZigBee networks for underground space monitoring and communication systems. The performance of ZigBee topologies are analysed in 12, 20, 30, 40 and 50-node scenarios for stationary node deployment in underground environments. The metrics used for the performance evaluation include throughput, packet delivery ratio (PDR), end-to-end delay, energy consumption and packet delivery security. The results evaluation confirms the mesh topology is prioritised in WSNs design considering higher throughput, packet delivery ratio and network security, while the cluster-tree topology is preferred in case of lower end-to-end delay and lower energy consumption. The analyses show that the mesh topology creates a more reliable monitoring and communication network with an adequate quality of service in underground spaces and tunnels. Therefore, greater end-to-end delay and energy consumption could not be major concerns for the mesh topology in underground mine applications based on the acceptable data latency and using mine power.
Time-Lapse Image Generation using Image-Based Modeling by CrowdsourcingHidehiko Shishido, Emi Kawasaki, Yutaka Ito, Youhei Kawamura, Toshiya Matsui, Itaru Kitahara2018 IEEE INTERNATIONAL CONFERENCE ON BIG DATA (BIG DATA) 3541 - 3542 2018年 [査読有り][通常論文] In recent years, the pillars of the World Heritage Angkor Thom Bayon temple have become a problem of deterioration due to moss breeding. We aim to generate an image to support observation of moss breeding on a pillar. Even under environment that prevent image processing, we can achieve accurate overlay processing by combining corresponding points between images and 3D shapes. In order to generate the timelapse image of the observation target, many accurate images of different capturing timings are necessary. We are going to use a lot of images collected by crowdsourcing for time lapse images. In this research, we use two crowdsourcing models with the »capturing image of the target region» and the »classification of the captured images» as the micro task. Therefore, image acquisition using crowdsourcing and generation of time lapse image are looped. Time lapse image will be more accurate by repeating this flow.
Comparison of Rock Fragmentation Measurement Systems with 3D System using Photogrammetry TechnologyKitahara, Itaru, Kawamura, Youhei, Topal, Erkan, Endo, Yasunori, Degawa, Ryo, Jang, HyongdooThe 2017 World Congress on Advances in Structural Engineering and Mechanics 2017年08月 [査読有り][通常論文]
Utilization of ultrasonic atomization for dust control in underground miningHirokazu Okawa, Kentaro Nishi, Youhei Kawamura, Takahiro Kato, Katsuyasu SugawaraJAPANESE JOURNAL OF APPLIED PHYSICS 56 7 2017年07月 [査読有り][通常論文] This study examined dust suppression using water particles generated by ultrasonic atomization (2.4 MHz) at low temperature (10 °C). Green tuff (4 μm), green tuff (6 μm), kaolin, and silica were used as dust samples. Even though ultrasonic atomization makes fine water particles, raising relative air humidity immediately was difficult at low temperature. However, remaining water particles that did not change to water vapor contributed to suppression of dust dispersion. Additionally, the effect of water vapor amount (absolute humidity) and water particles generated by ultrasonic atomization on the amount of dust dispersion was investigated using experimental data at temperatures of 10, 20, and 30 °C. Utilization of ultrasound atomization at low temperature has the advantages of low humidity increments in the working space and water particles remaining stable even with low relative air humidity.
Proactive Preservation of World Heritage by Crowdsourcing and 3D Reconstruction TechnologyHidehiko Shishido, Yutaka Ito, Youhei Kawamura, Toshiya Matsui, Atsuyuki Morishima, Itaru Kitahara2017 IEEE INTERNATIONAL CONFERENCE ON BIG DATA (BIG DATA) 2018-January 4426 - 4428 2017年07月01日 [査読有り][通常論文] Since over one million tourists annually visit the Angkor ruins, the effect on the buildings from the vibrations caused by these tourists is a huge problem for maintaining them. Such organisms as bryophytes, which adhere to the surface of the stones of the ruins, is another factor that damages them. Using crowdsourcing and 3D reconstruction technology, we are organizing a proactive preservation project for the Angkor Thom Bayon Temple, which is a world cultural heritage site. We evaluated its damaged parts and visualized the damaged state.
Illumination of parameter contributions on uneven break phenomenon in underground stoping minesJang Hyongdoo, Topal Erkan, Kawamura YouheiINTERNATIONAL JOURNAL OF MINING SCIENCE AND TECHNOLOGY 26 6 1095 - 1100 2016年11月01日 [査読有り][通常論文] One of the most serious conundrum facing the stope production in underground metalliferous mining is uneven break (UB: unplanned dilution and ore-loss). Although the UB has a huge economic fallout to the entire mining process, it is practically unavoidable due to the complex causing mechanism. In this study, the contribution of ten major UB causative parameters has been scrutinised based on a published UB predicting artificial neuron network (ANN) model to put UB under the engineering management. Two typical ANN sensitivity analysis methods, i.e., connection weight algorithm (CWA) and profile method (PM) have been applied. As a result of CWA and PM applications, adjusted Q rate (AQ) revealed as the most influential parameter to UB with contribution of 22.40% in CWA and 20.48% in PM respectively. The findings of this study can be used as an important reference in stope design, production, and reconciliation stages on underground stoping mine.
Development of a Landslide Observation System Using ZigBee Wireless Communication TechnologyY. Kawamura, H. Jang, K. Ohta, Y. InagakiGeotechnical Special Publication 2016-January 269 GSP 542 - 550 2016年 [査読有り][通常論文] Extensive area of Japan is subjected to threats of potential landslides as roughly 70 percent of Japan consists of a steep mountainous terrain and moreover numerous artificial hill slopes are developed in residential areas. While various types of structural counter measures have been developed and successfully implemented in Japan, significant numbers of areas remain unprotected. Hence, non-structural measures, such as hazard maps and early warning systems, are required to minimize risks. One of the key technologies of the early warning system is the automatic detection system for landslides. In this research, we are developing an automatic detection system for landslides using ZigBee wireless communication technology. A general ZigBee-compliant platform made by Hitachi Co. Ltd. was customized and used in the constructing the wireless landslide detection system. The developed system monitors various environmental data, such as 3-axes acceleration, temperature, humidity, and illumination intensity. It was verified that all measured parameters except humidity were measured properly at an actual slope site with the proposed system.
3D Model Reconstruction of Rocks on a Slope for Simulating a Rock FallItaru Kitahra, Shogo Atsumi, Ryo Degawa, Youhei Kawamura, Hyongdoo Jang, Yuichi OhtaGeotechnical Special Publication 2016- 269 508 - 517 2016年 [査読有り][通常論文] For reducing damage of rock fall, it is important to estimate the route, leap height and velocity of the rock. Although research about estimation of falling motion of rocks are actively conducted, there are still unsolved issues, since rock fall is a complex phenomenon affected by position, size, or shape of rocks and angle of slope. This paper proposes a method of rock fall simulation using a 3D model of rock and slope reconstructed by merging multiple-view images. The proposed method requires only a mobile camera to generate a 3D model, so that more practical rock fall simulation can be realized. In addition, reconstructing textured 3D model makes inspectors visually confirm how the rock falls on the slope. Due to the difficulty capturing multiple images of both of rocks and a slope at a same time, rocks and a slope are individually captured, and then, they are merged in the post process. There are two problems to be solved for merging them accurately. One is the significant difference in their spatial resolution the other is the difference in the appearance caused by perspective projection. We conduct an experiments using multiple images of rocks and slopes captured at actual landslide site.
An Automated Sensing System for Steel Bridge Inspection Using GMR Sensor Array and Magnetic Wheels of Climbing RobotRui Wang, Youhei KawamuraJOURNAL OF SENSORS 2016 8121678 - 15 2016年 [査読有り][通常論文] Corrosion is one of the main causes of deterioration of steel bridges. It may cause metal loss and fatigue cracks in the steel components, which would lead to the collapse of steel bridges. This paper presents an automated sensing system to detect corrosion, crack, and other kinds of defects using a GMR (Giant Magnetoresistance) sensor array. Defects will change the relative permeability and electrical conductivity of the material. As a result, magnetic field density generated by ferromagnetic material and the magnetic wheels will be changed. The defects are able to be detected by using GMR sensor array to measure the changes of magnetic flux density. In this study, magnetic wheels are used not only as the adhesion device of the robot, but also as an excitation source to provide the exciting magnetic field for the sensing system. Furthermore, compared to the eddy current method and the MFL (magnetic flux leakage) method, this sensing system suppresses the noise from lift-off value fluctuation by measuring the vertical component of induced magnetic field that is perpendicular to the surface of the specimen in the corrosion inspection. Simulations and experimental results validated the feasibility of the system for the automated defect inspection.
Development of climbing robot for steel bridge inspectionRui Wang, Youhei KawamuraINDUSTRIAL ROBOT-THE INTERNATIONAL JOURNAL OF ROBOTICS RESEARCH AND APPLICATION 43 4 429 - 447 2016年 [査読有り][通常論文] Purpose - The purpose of this paper is to present a design of climbing robot with magnetic wheels which can move on the surface of steel bridge. The locomotion concept is based on adapted lightweight magnetic wheel units with relatively high attractive force and friction force. Design/methodology/approach - The robot has the main advantages of being compact (352 - 215 - 155 mm), lightweight (2.3 kg without battery) and simple mechanical structure. It is not only able to climb vertical walls and follow circumferential paths, but also able to pass complex obstacles such as bolts, steps, convex and concave corners with almost any inclination regarding gravity. By using a servo as a compliant joint, the wheel base can be changed to enable the robot to overcome convex corners. Findings - The experiment results show that the climbing robot has a good performance on locomotion, and it is successful in negotiating the complex obstacles. On the other hand, the limitations in locomotion of the robot are also presented. Originality/value - Compared with the past researches, the robot shows good performance on overcoming complex obstacles such as concave corners, convex corners, bolts and steps on the steel bridge. Magnetic wheel with the characterization of compact size and lightweight is able to provide bigger adhesion force and friction coefficient.
A Multimedia Data Visualization Based on Ad Hoc Communication Networks and Its Application to Disaster ManagementYouhei Kawamura, Markus Wagner, Hyongdoo Jang, Hajime Nobuhara, Takeshi Shibuya, Itaru Kitahara, Ashraf M. Dewan, Bert VeenendaalISPRS INTERNATIONAL JOURNAL OF GEO-INFORMATION 4 4 2004 - 2018 2015年12月 [査読有り][通常論文] After massive earthquakes and other large-scale disasters, existing communication infrastructure may become unavailable and, therefore, it can be quite difficult for relief organizations to fully grasp the impact of the disaster on the affected region. Consequently, this will be the cause of delays to offer the strategic assistance, and to provide water and food, etc. In order to solve the problem of re-establishing communication infrastructure to allow for information gathering, we developed an ad hoc mobile communications network for disaster-struck areas using ZigBee. As the communication speed of ZigBee is low, we propose a problem-specific image compression method for the multimedia data visualization. By using the proposed method combined with GPS information, it is possible to quickly grasp the damage situation in the region. Through our communication experiments in Tsukuba City, Japan we confirm the effectiveness of our system as a disaster information gathering and management system.
Development of underground mine monitoring and communication system integrated ZigBee and GISMoridi Mohammad Ali, Kawamura Youhei, Sharifzadeh Mostafa, Chanda Emmanuel Knox, Wagner Markus, Jang Hyongdoo, Okawa HirokazuINTERNATIONAL JOURNAL OF MINING SCIENCE AND TECHNOLOGY 25 5 811 - 818 2015年09月01日 [査読有り][通常論文] An automated underground mine monitoring and communication system based on the integration of new technologies is introduced to promote safety and health, operational management and cost-effectiveness. The proposed system integration considering Wireless Sensor Network (WSN) assisted Geographic Information System (GIS) enables to monitor and control underground mining applications from surface office. Based on the capabilities of WSNs, ZigBee network is adapted for near real-time monitoring, ventilation system control and emergency communication in underground mine. ZigBee nodes were developed to sense environmental attributes such as temperature, humidity and gases concentration; switching ON and OFF ventilation fans; and texting emergency messages. A trigger action plan for monitored attributes above normal and threshold value limits is programmed in the surface GIS management server. It is designed to turn the auxiliary fans on remotely or automatically in orange condition and sending evacuation messages for underground miners in unsafe (red) condition. Multi-users operation and 3D visualisations are other successful achievements of the proposed system for the underground monitoring and communication.
Analysis of Radio Wave Propagation in an Urban Environment and its Application to Initial Disaster Response SupportYouhei Kawamura, Hyongdoo Jang, Markus Wagner, Hajime Nobuhara, Ashraf M. Dewan, Bert Veenendaal, Itaru KitaharaJOURNAL OF DISASTER RESEARCH 10 4 655 - 666 2015年08月01日 [査読有り][通常論文] When disasters strike, it is important to quickly collect and analyze disaster-related information immediately after the event. We have suggested ZigBee and geographic information systems (GIS) technologies to resolve these problems and provide an effective communications system. In this paper, a method for the rapid setup of short-range wireless networks infrastructure, which estimates the radio wave propagation and optimizes the positions of transmitters is proposed. Our estimation method is experimentally verified, and it combines ray-tracing with preliminarily obtained statistical attenuation information, which allows us to consider different types of the land and its elevation. Thus, we can determine the effective ranges for radio communication for each potential location in the actual environment. This information is then used in our optimization procedure to reduce the number of transmitters needed to establish connections.
Removal of arsenious acid from sulfuric acidic solution using ultrasound oxidation and goethiteHirokazu Okawa, Tomohiro Yoshikawa, Ryota Hosokawa, Shinji Hangui, Youhei Kawamura, Katsuyasu SugawaraJAPANESE JOURNAL OF APPLIED PHYSICS 54 7 2015年07月01日 [査読有り][通常論文] We investigated the properties of synthetic goethite for the adsorption of As from strongly acidic solutions in ambient atmosphere under ultrasound irradiation. The goethite was successfully synthesized from iron-containing sulfuric acidic solution (1271 ppm) using an autoclave apparatus for 1h at 0.12MPa and 121 °C. The ratio of the iron eluted from the synthetic goethite to the acidic solution was only 0.58% at pH 2.1. Ultrasound irradiation (200 kHz, 200 W) was applied to oxidize 10 ppm of As(III) to As(V) at pH 2.2 for 60 min under various atmospheric conditions. Remarkably, the oxidation ratio of As(III) to As(V) is quite high (89.7%) at pH 2.2 in ambient atmosphere and is close to those obtained for Ar (95.3%) and O2 (95.9%) atmospheres. The As(III) removal ratio reached 94.5% after 60 min of irradiation. Therefore, goethite is a promising material for As adsorption using ultrasound oxidation in the acidic region in ambient atmosphere.
Decision support system of unplanned dilution and ore-loss in underground stoping operations using a neuro-fuzzy systemHyongdoo Jang, Erkan Topal, Youhei KawamuraAPPLIED SOFT COMPUTING 32 1 - 12 2015年07月01日 [査読有り][通常論文] Abstract Unplanned dilution and ore-loss are the most critical challenges in underground stoping operations. These problems are the main cause behind a mine closure and directly influencing the productivity of the underground stope mining and the profitability of the entire operation. Despite being aware of the significance of unplanned dilution and ore-loss, prediction of these phenomena is still unexplained as they occur through complex mechanisms and causative factors. Current management practices primarily rely on similar stope reconciliation data and the intuition of expert mining engineers. In this study, an innovative unplanned dilution and ore-loss (uneven break: UB) management system is established using a neuro-fuzzy system. The aim of the proposed decision support system is to overcome the UB phenomenon in underground stope blasting which provides quantitative prediction of unplanned dilution and ore-loss with practical recommendations simultaneously. To achieve the method proposed, an uneven break (UB) prediction system was developed by an artificial neural network (ANN) considering 1076 datasets covering 10 major UB causative factors collected from three underground stoping mines in Western Australia. In succession, the UB consultation system was established via a fuzzy expert system (FES) in reference to surveyed results of fifteen underground-mining experts. The UB prediction and consultation system were combined as one concurrent neuro-fuzzy system that is named the 'uneven break optimiser'. Because the current UB prediction systems in investigated mines were highly unsatisfactory with correlation coefficient (R) of 0.088 and limited to only unplanned dilution, the performance of the proposed UB prediction system (R of 0.719) is a remarkable achievement. The uneven break optimiser can be directly employed to improve underground stoping production, and this tool will be beneficial not only for underground stope planning and design but also for production management.
Unplanned dilution and ore loss prediction in longhole stoping mines via multiple regression and artificial neural network analysesH. Jang, E. Topal, Y. KawamuraJOURNAL OF THE SOUTHERN AFRICAN INSTITUTE OF MINING AND METALLURGY 115 5 449 - 456 2015年05月 [査読有り][通常論文] Unplanned dilution and ore loss directly influence not only the productivity of underground stopes, but also the profitability of the entire mining process. Stope dilution is a result of complex interactions between a number of factors, and cannot be predicted prior to mining. In this study, unplanned dilution and ore loss prediction models were established using multiple linear and nonlinear regression analysis (MLRA and MNRA), as well as an artificial neural network (ANN) method based on 1067 datasets with ten causative factors from three underground longhole stoping mines in Western Australia. Models were established for individual mines, as well as a general model that includes all of the mine data-sets. The correlation coefficient (R) was used to evaluate the methods, and the values for MLRA, MNRA, and ANN compared with the general model were 0.419, 0.438, and 0.719, respectively. Considering that the current unplanned dilution and ore loss prediction for the mines investigated yielded an R of 0.088, the ANN model results are noteworthy. The proposed ANN model can be used directly as a practical tool to predict unplanned dilution and ore loss in mines, which will not only enhance productivity, but will also be beneficial for stope planning and design.
Unplanned dilution and ore loss prediction in longhole stoping mines via multiple regression and artificial neural network analysesH. Jang, E. Topal, Y. KawamuraJournal of the Southern African Institute of Mining and Metallurgy 115 5 449 - 456 2015年 [査読有り][通常論文] Unplanned dilution and ore loss directly influence not only the productivity of underground stopes, but also the profitability of the entire mining process. Stope dilution is a result of complex interactions between a number of factors, and cannot be predicted prior to mining. In this study, unplanned dilution and ore loss prediction models were established using multiple linear and nonlinear regression analysis (MLRA and MNRA), as well as an artificial neural network (ANN) method based on 1067 datasets with ten causative factors from three underground longhole stoping mines in Western Australia. Models were established for individual mines, as well as a general model that includes all of the mine data-sets. The correlation coefficient (R) was used to evaluate the methods, and the values for MLRA, MNRA, and ANN compared with the general model were 0.419, 0.438, and 0.719, respectively. Considering that the current unplanned dilution and ore loss prediction for the mines investigated yielded an R of 0.088, the ANN model results are noteworthy. The proposed ANN model can be used directly as a practical tool to predict unplanned dilution and ore loss in mines, which will not only enhance productivity, but will also be beneficial for stope planning and design.
直達音と地面反射音を利用する少素子ジオフォンアレイによる土中音源位置測定川岸,卓司, 善甫,啓一, 水谷,孝一, 若槻,尚斗, 川村,洋平土木学会論文集F3（土木情報学） 69 2 I_130 - I_138 Japan Society of Civil Engineers 2014年03月 [査読有り][通常論文] 本稿は土中で発生する音源の位置測定法に関するものである．提案手法では，直達音だけではなく，地表面からの反射音も利用することで測定精度の向上を図っている．地表面で起こる反射音を利用するために，鉛直方向に一対の素子を配置した杭状のジオフォンを用いている．杭状ジオフォンアレイを2本（素子数：4）用いた評価実験の結果，位置推定精度は直達音のみを使用する従来手法と比べ3.42倍と向上することがわかった．また，ジオフォンアレイの配置や構成する素子のずれが音源位置の推定に与える影響を実規模シミュレーションにより実験し，提案手法の位置推定精度は従来手法に比べ最大で14.6倍に向上できることを確認した．以上より，従来手法に比べ高精度の音源位置測定が可能であることが示された．
Development of underground mine communication and monitoring systems by using ZigBee technologyY. Kawamura, M. A. Moridi, M. Sharifzadeh, H. JangISRM International Symposium - 8th Asian Rock Mechanics Symposium, ARMS 2014 1411 - 1420 2014年 Data transfer and communication systems are first priority for further development of geotechnical monitoring. This paper describes a Wireless Sensor Network (WSN) for communication and monitoring systems based on ZigBee technology in underground mines. Wireless sensor networks (WSNs) have been widely employed in industries and the military with multiple applications to monitor environment, track target and telecommunicate data. Recently, WSNs have also been used for communication and monitoring systems in underground mines. In this study, a proposed WSN system of ZigBee network as one of the WSNs is investigated in underground mines regarding communication and monitoring systems to resolve operational challenges such as safety and gathering geotechnical information. Developed ZigBee wireless network system was installed in Paddington Gold Underground Mine (managed by Norton Gold Fields Limited). In this research, the intensity of received signal strength indication (RSSI) between wireless nodes within ZigBee network was investigated. Also, the optimal arrangement of ZigBee wireless nodes on the basis of radio wave attenuation and possibility of stable wireless communications which will be used for gathering some significant geotechnical information such as seismic, deformation and pressure were investigated. The experimental results indicate that a secure and stable ZigBee wireless network can be developed to overcome mentioned operational challenges in underground mining. It is obvious that this proposed system helps further progress in rock mechanics and geotechnical fields.
Illustrating quality of life (QOL)Ashraf M. Dewan, Kamrun Nahar, Yohei KawamuraDhaka Megacity: Geospatial Perspectives on Urbanisation, Environment and Health 239 - 256 2014年01月01日 The objective of this chapter is to develop a quality of life (QOL) index at community level in the Dhaka City Corporation (DCC) area, which could describe the spatial patterns of QOL. Using remote sensing, census and other spatial data, a factor analysis was carried out to develop the different dimensions of QOL. Three principal factors were extracted from the analysis: environmental, economic and demographic. These three factors were then combined in a Geographic Information Systems (GIS) environment to construct a synthetic QOL for the study area. The results were subsequently validated using regression analysis, which revealed a better prediction of QOL based on environmental and socioeconomic variables. Interestingly, only a small portion of the population (1.4 %) in the study area was shown to have good QOL. As higher urban growth driven by rapid rural-urban migration is expected in Dhaka in the coming years, this study will be of substantial help for urban planners and policymakers in formulating related policies to ensure a better living environment for its inhabitants.
A Magnetic Climbing Robot for Steel Bridge InspectionRui Wang, Youhei Kawamura2014 11TH WORLD CONGRESS ON INTELLIGENT CONTROL AND AUTOMATION (WCICA) 2015-March March 3303 - 3308 2014年 [査読有り][通常論文] Corrosion can cause section loss or cracks in the steel members which is one of the most important causes of deterioration of steel bridges. For some critical components of a steel bridge, it is fatal and could even cause the collapse of the whole bridge. Nowadays the most common approach to steel bridge inspection is visual inspection by inspectors with inspection trucks. This paper mainly presents a climbing robot with magnetic wheels which can move on the surface of steel bridge. Experiment results shows that the climbing robot can move on the steel bridge freely without disrupting traffic to reduce the risks to the inspectors.
A6 オイルサンドからのビチューメン分離回収における超音波利用の検討(口頭発表)大川 浩一, 斉藤 知直, 菅原 勝康, 川村 洋平, Babadagli Tayfunソノケミストリー討論会講演論文集 22 11 - 12 日本ソノケミストリー学会 2013年 20% of Canada's oil sand is located on the surface of the ground. These oil sands are taken by means of open-pit mining. Oil sands contain about 10% bitumen. Bitumen is used as fuel energy, and it is necessary to separate bitumen from oil sand at high efficiency. Main industrial processes to separate bitumen from oil sand are treatments using hot water and steam in rotating drums. These treatments consist of two processes. The first is the bitumen separation from oil sand and the second is the bitumen flotation from aqueous solution to the solution surface. In this study, the role of high concentrated H_2O_2 to recover bitumen during sonication was investigated. Furthermore, we investigated the optimal combination of ultrasound and gases to improve the separation efficiency and the yield of bitumen from oil sand in the hot water process.
Emergency management withZigBeeand GISYouhei Kawamura, Bert Veenendaal, Ashraf M. Dewan, Masahiro Hayashi, Itaru Kitahara, Hajime Nobuhara, Kento IshiiISCIIA 2012 - 5th International Symposium on Computational Intelligence and Industrial Applications 2012年 Communications network damage resulting from a large disaster causes difficulties in the ability to rapidly understand the current situation and thus make appropriate decisions toward mitigating problems. This research focuses on the rapid construction of a network after a disaster occurs. This study suggests ZigBee and GIS technologies to resolve these problems and provide an effective communications system. This paper provides ground design of the emergency management system with ZigBee network and GIS technologies. In this paper, it was demonstrated the effectiveness of establishing such a communications system for supporting efforts to relieve disaster-damaged areas.
Development of digbot for monitoring the underground environmentMasahiro Hayashi, Toshiyuki Miyachi, Youhei Kawamura, Kazutoshi Murakami, Yuichi Kato, Hiroshi MochiyamaISCIIA 2012 - 5th International Symposium on Computational Intelligence and Industrial Applications 2012年 A digging robot named "DigBot" has been developed by our laboratory for monitoring the underground environment and exploring the lunar surface. The purpose of this research is to develop the robot which can dig soil and sand automatically. When we build the building or structure, ground research is indispensable to know that if the ground can hold the building. In addition, conceivable application of DigBot is investigation of geological condition and ground pollution after disaster. Standard penetration test and Swedish weight sounding test are known as the general way of ground research and are frequently used. But these methods have faults. For example, high costs or large scale. In this proceeding, first, concept of DigBot is shown. As a basic research of developing DigBot, Contra-rotating drill is developed and made for trial purpose. And then digging experiment is carried out for verifying effectiveness through the Contra-rotating drill. It was proved that DigBot possess incomparably more power than ever before. This research suggest the way of solving faults by using the robot which can dig underground and research underground information.
Efficient construction ofwireless personal area networks for disaster controlSeiji Yasunobu, Hajime Nobuhara, Yohei KawamuraISCIIA 2012 - 5th International Symposium on Computational Intelligence and Industrial Applications 2012年 Japan and Indonesia are the earthquake occurrence countries where located in the circum-Pacific volcanic zone. Researches on disaster recovery management have been important issues for both countries. Our research proposes a Disaster Recovery Management system based on the proposed low cost short-distance wireless (ZigBee) communication network and mobile phones. If every person in the disaster area is connected to this network, then the information of the position, injured person, died person, and lost person can be identified quickly. The information is processed using our soft computing method to generate a comprehensive recovery and mitigation plan. Then, the government and the rescue team can use this recovery and mitigation plan for disaster management. Also, civilian organizations can develop own rescue projects based on the proposed networks. This can shorten time in the disaster management process therefore the number of victims can be reduced.
Sonication Enables Effective Iron Leaching from Green Tuff at Low TemperatureTakashi Nakamura, Hirokazu Okawa, Youhei Kawamura, Katsuyasu SugawaraJAPANESE JOURNAL OF APPLIED PHYSICS 50 7 07HE16 - 07HE16-4 2011年07月 [査読有り][通常論文] Ultrasound irradiation (28 and 200 kHz) was applied to iron leaching from green tuff into a low temperature solution (20 degrees C) using oxalic acid. Ultrasound irradiation increased the amount of iron leached from the green tuff and was greater than that leached by stirring. It is thought that the jet flow caused by the collapse of cavities during ultrasound irradiation prevents and strips the deposits of iron oxalate from the green tuff particles. The extraction of iron at 28 kHz displayed better performance than that at 200 kHz for three reasons. The first is that the jet flow generated by cavitation bubble collapse at 28 kHz is thought to be stronger than that at 200 kHz. The second is that the crushing action of ultrasound irradiation at 28 kHz is greater than that at 200 kHz. The third is that 200 kHz irradiation generates OH radicals, which prevents the generation of FeH(C(2)O(4))(+) and oxidizes FeH(C(2)O(4))(+) to Fe(C(2)O(4)), creating a cover layer on the surface of the stone. Thus, to leach iron from the ore, it is effective to use ultrasound irradiation at 28 kHz, which prevents the creation of radicals and breaks down the grain size. (C) 2011 The Japan Society of Applied Physics
超磁歪振動子を利用した極浅層における地中映像化システムに関する研究蒲原, 章裕, 川村, 洋平, 鎌形, 真伍, 大川, 浩一Journal of MMIJ : journal of the Mining and Materials Processing Institute of Japan 127 4 182 - 188 社団法人 資源・素材学会 2011年03月 [査読有り][通常論文] Recently, Water and gas pipes are developed frequently because of the increased urban population. When the underground piping is constructed, drawings and signs are needed to drill the ground. However, underground pipings and other buried objects are often buried in different locationscompared with drawings. Underground pipings, the rock and the gravel interfere with construction. It is necessary to avoid this situation. To determine the construction of underground pipes, the non-destructive imaging method previously detects the pipe inside the ground. This paper describes a system of ultrashallow underground imaging method using seismic reflection and seismic giant magnetostrictive transducer. We apply a surface wave analysis using a giant magnetostrictive transducer. We improve the accuracy of P wave velocity. For the high-efficiency setup and the underground imaging succeed. This system combines ultrashallow seismic reflection and the ultra-magnetostrictive transducer. It provides the practical system.
The Sterilization of Suspensions Contaminated with Microorganisms Using Ultrasound IrradiationNakamura, Takashi, Okawa, Hirokazu, Hosokawa, Ryouta, Saito, Tomonao, Kawamura, Youhei, Sugawara, KatsuyasuJpn J Appl Phys 49 7 07HE11 - 07HE11-4 Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physics 2010年07月 [査読有り][通常論文] We investigated the influence of suspended particles on the sterilization efficiency of ultrasound wave applied to microbial suspensions. A microbial solution containing $2.0\times 10^{2}$ cfu/ml of Bacillus bacteria but no suspended particles was sterilized more efficiently by 28 kHz irradiation inducing a strong impact-like physical action compared to 200 kHz irradiation inducing a strong chemical reaction through the generation of radicals and heat. This sterilization effect was enhanced by the suspension of silicon dioxide or green tuff when irradiated at 28 kHz. However, the irradiation of green tuff microbial suspension at 200 kHz resulted in a remarkable decrease in the sterilization efficiency. This reduction was caused by divalent iron in green tuff reacting with radicals generated by 200 kHz irradiation, thus reducing the amount of radicals used for sterilization. Our results suggest that 28 kHz ultrasound irradiation is optimal for the sterilization of microbial suspensions.
20712 磁気車輪を用いた鉄橋非破壊検査装置のための移動機構の開発(一般講演 ロボット)土方, 大輔, 川村, 洋平, 宇都木, 隆裕日本機械学会関東支部総会講演会講演論文集 2010 16 231 - 232 一般社団法人日本機械学会 2010年03月 [査読無し][通常論文] We develop a mobile mechanism that can move on the surface of the iron bridge for a non-destructive testing device. This mechanism has four-wheel drive and moves by means of magnetic wheels. It acquires adhesion force efficiently by using the principle of the magnetic circuit. This mechanism achieved vertical plane running. Next, we analyze mechanics when the machine approaches a step. It turns out that getting over steps and climbing a vertical plane become possible by selecting the appropriate parameter. It was confirmed by the experiment.
P13 超音波を用いたトリクロロエチレン汚染懸濁液の浄化(ポスター発表)大川 浩一, 中村 貴司, 川村 洋平, 菅原 勝康ソノケミストリー討論会講演論文集 19 45 - 46 日本ソノケミストリー学会 2010年 In this paper, we demonstrate in a treatment method for suspension contaminated with trichloroethylene (TCE). The objectives of the present work are to study the purifying the suspension contaminated with TCE and the precipitating the fine particles in the suspension using ultrasound irradiation. Suspension and solution were prepared by ion-change water, TCE and green tuff. TCE solution (500ppm) was completely decomposed for 2h sonication in argon atmosphere. And TCE in suspension (500ppm) was also confirmed the completely decomposition at same condition. Compared the decomposition rate of TCE in solution and suspension, the value were almost same. Isoelectric zone of green tuff suspension was 1.4-3.8 in pH. Degradation of TCE generated which was able to be acidified the solution and the suspension to the pH level of the isoelectric zone. TCE purifying and solid-liquid separation of the suspension using ultrasound irradiation was feasible.
Viscosity Measurement Method using Induced EMF at Coil in PVT ApparatusH.ANDO, Y.KAWAMURA, H.OKAWA, Y.SUGAI, and, K.SASAKI, 川村, 洋平International Symposium on Earth Science and Technology 2009 443-446 2009年12月 [査読有り][通常論文]
A Fundamental Study of the Surface-Wave Method: The Use of a Giant-Magnetostriction Vibrator as Seismic SourceA.KAMOHARA, Y.KAWAMURA, Y.NAKAHATA, H.OKAWA, and, K.MIZUTANI, 川村, 洋平International Symposium on Earth Science and Technology 2009 437-442 2009年12月 [査読有り][通常論文]
超音波を利用した比内緑色凝灰岩懸濁液の沈殿処理に関する研究中村, 貴司, 大川, 浩一, 川村, 洋平, 高畑, 重幸, 中, 秀男, 菅原, 勝康環境資源工学 : 資源処理技術 / 環境資源工学会 [編] 56 1 13 - 20 環境資源工学会 2009年04月 [査読有り][通常論文] Hinai green tuff is quarried in Odate-shi, Akita prefecture in Japan and used for architectural materials. Hinai green tuff suspension is generated from the cutting and the grinding process and it is necessary to treat the solution with precipitants. A chemical flocculant has been used as a precipitation agent for fine particles in the suspension. However, using a chemical flocculant agent produces a wasteful mixture of particles and flocculants, which are impossible to be used as a resource. Therefore, it is necessary to develop a new precipitation method without using precipitants for green tuff particles. In this study, the zeta potential of Hinai green tuff particles in suspension was measured to gain the basic electrochemical properties of the colloidal suspension. We then developed a new precipitation method using sonochemical reaction at 200 kHz, 200 W. From results of the zeta potential measurement using an electrophoresis method, the particles exhibited −50 mV at pH 7.0 and 0 mV at below pH 4.0. Sonochemical reaction was applied to control the pH of the suspension to precipitate the Hinai green tuff particulate. When ultrasonic irradiation was applied to the Hinai green
P21 超音波を用いた有機塩素化合物汚染懸濁液の浄化中村 貴司, 大川 浩一, 川村 洋平, 菅原 勝康ソノケミストリー討論会講演論文集 18 69 - 70 日本ソノケミストリー学会 2009年 We present a method to treat suspension contaminated with trichloroethylene (TCE). We aimed to remove TCE and precipitate the fine particles in the suspension using ultrasound irradiation. The solution was prepared from ion-change water and TCE. The suspension was prepared from the solution and green tuff. TCE solution (500ppm) was completely decomposed by 2h sonication in argon atmosphere. And the complete decomposition of TCE in suspension (500ppm) was also confirmed at the same condition. The decomposition rate of TCE in solution and suspension were almost same. Isoelectric zone of green tuff suspension was 1.4-3.8 in pH. The degradation of TCE acidified the solution and brought the pH level of the suspension to the isoelectric zone. Thus, it is feasible to remove TCE and precipitate fine particles in the suspension using ultrasound irradiation.
地中配管検知を目的とした楕円軌道輝度値法による極浅層映像化川村 洋平, 河 宜成, 蒲原 章裕, 大川 浩一Journal of MMIJ : journal of the Mining and Materials Processing Institute of Japan 124 12 801 - 807 資源・素材学会 2008年12月25日 [査読有り][通常論文] When underground piping for a water or gas supply is buried, the construction site should be checked in advance, referring to the plan or sign. However, some obstacles, such as unknown pipes or stones, can be encountered. To avoid these cases, an examination of the underground condition is required. The purpose of this study is to detect underground objects that exist in the ultra-shallow layer, where 2-3 m below the surface, and to obtain underground image which is easy to see intuitively. For detection, seismic method is applied. However, this method has two downsides. One is a generally used seismic source not having reproducibility. The other is mixing Rayleigh wave which is one of the surface waves and reflected waves. To compensate these downsides, giant-magnetostriction vibrator was used as a seismic source, and magnified cross-correlation analysis was proposed. Underground image was obtained using combinations of them. In this paper, as the method of underground imaging, new algorithm of elliptic orbit brightness value it was developed by the authors was used.
Accuracy Improvement of Cepstrum Analysis Using Giant-magnetostriction Vibrator Applied to Non-destructive Testing for Crack of Rock SlopeM.Asaka, Y.Kawamura, H.Okawa, K.Mizutani, 川村, 洋平Proceedings of the 17th Int. Symposium on Mine Planning and Equipment Selection 744-754 2008年10月 [査読有り][通常論文]
超磁歪振動子を用いたコンクリート構造物・岩盤斜面に対する非破壊検査におけるケプストラム解析の適用性川村 洋平, 浅香 充慶, 河 宜成, 大川 浩一, 水谷 孝一Journal of MMIJ : journal of the Mining and Materials Processing Institute of Japan 124 6 452 - 458 一般社団法人 資源・素材学会 2008年07月25日 [査読有り][通常論文] Buildings are often damaged by earthquake and land sinkage. Moreover, in Japan, concrete constructions built during the period of high economic growth are getting old. On the other hand, due to weather and geographical features, the collapse of rock slope occurs in many places. So, authors have been conducting a study of the safety assessment of concrete constructions and rock slope using reflection wave method. In this study, the giant-magnetostriction vibrator was used as a transducer to input the ultrasonic wave into a concrete block. Giant-magnetostriction vibrators have much greater input power than piezo-electric ceramics. So, the safety assessment of large scale objects that do not respond with piezo-electric ceramics is possible. These researches are generally called "Non-destructive testing" and herculean task due to the influence of direct wave, because the output wave contains a wave with direct wave and reflection wave together. In this study, as the method to detect the reflection wave, cepstrum analysis was adopted, and arrival times of reflection waves from the bottom of concrete block are shown. The result of cepstrum analysis is greatly influenced by the noise. To improve the result of analysis, the window function which is used in the process of cepustrum analysis was focused, and reduced the influence of direct wave using input voltage waveform. Moreover, the addition of the results of cepstrum analyses in different frequency was applied and the result was greatly improved. The result of this research shows that the cepstrum analysis with giant-magnetostriction vibrator for non-destructive testing is available.
A13 超音波を利用した比内緑色凝灰岩懸濁液の沈殿処理に関する研究(口頭発表)中村 貴司, 大川 浩一, 川村 洋平, 菅原 勝康ソノケミストリー討論会講演論文集 17 36 - 37 日本ソノケミストリー学会 2008年 Hinai green tuff is quarried in Odate-shi, Akita prefecture in Japan and used for architectural materials. Hinai green tuff suspension is generated from the grinding process and it is necessary to treat the solution with precipitants. A chemical flocculant has been used as a precipitation agent for fine particles in the suspension. However, using a chemical flocculant agent produces a wasteful mixture of particles and flocculants, which are impossible to be used as a resource. Therefore, it is necessary to develop a new precipitation method without using precipitants for green tuff particles. In this study, the zeta potential of Hinai green tuff particles in suspension was measured to gain the basic electrochemical properties of the suspension. We then developed a new precipitation method using sonochemical reaction at 200kHz, 200W. From results of the zeta potential measurement using an electrophoresis method, the particles exhibited 0mV at below pH 4.5. Sonochemical reaction was applied to control the pH of the suspension to precipitate the Hinai green tuff particulate. When ultrasonic irradiation was applied to the Hinai green tuff suspension, the pH decreased to 4.5 in 70 min and finally reached 3.4 in 180 min. We successfully extracted pure Hinai green tuff particles as precipitates from the suspension using ultrasound irradiation.
P07 リチウムイオン二次電池用正極材料LiFePO_4の超音波合成(第I部,ポスター発表)工藤 陽太, 大川 浩一, 川村 洋平, 菅原 勝康, 佐藤 峰夫ソノケミストリー討論会講演論文集 17 54 - 55 日本ソノケミストリー学会 2008年 Lithium iron phosphate has attracted attention as a promising cathode material for lithium ion battery, because of its less expensive, abundance. However, the battery capability of this material is at present limited by its low electronic conductivity and low lithium diffusion rate. In order to improve the poor diffusion of lithium ions and the low electronic conductivity, mainly two possible approaches have been studied. One is to increase the surface area of active materials which can reduce the ion-diffusion pathway, and the other is to deposit conductive carbon layers on the surface to improve electronic conductivity. Since the surface area is dependent on the particle size of LiFePO_4, the synthetic method is very important to control the particle size. In this study, Olivine-type LiFePO_4 was prepared via a sonochemical reaction to gain the fine particles. LiOH・H_2O, (NH_4)_2HPO_4 and FeSO_4・7H_2O were used as the starting materials. An Alcohol was added to the solution of the raw materials. When ultrasonic irradiation upon an alcohol, it is so effective for prohibition of conversion from Fe^<2+> to Fe^<3+> in the solution without reducing agent. The precipitate prepared from the solution gave fine particles of LiFePO_4 after calcination. The LiFePO_4 powders obtained was of homogeneity and globular structure with sub-micron particle sizes.
筑波大学 川村研究室 : Geo-Sensing川村 洋平計測と制御 = Journal of the Society of Instrument and Control Engineers 46 10 815 - 816 2007年10月10日 [査読有り][通常論文]
Study on Correspondence between Output Voltage of Cable Sensor for Vibration Detection and VelocityY.Kudo, Y.Kawamura, K.Oumura, H.Okawa, and, K.Mizutani, 川村, 洋平Proceedings of the 16th Int. Symposium on Mine Planning and Equipment Selection 524-531 2007年09月 [査読有り][通常論文]
The detection of a misfiring cylinder of diesel engines in excavation machinery using ALM analysisY. Kawamura, M. Nagayama, M. UjihiraInternational Journal of Mining, Reclamation and Environment 21 2 97 - 110 2007年06月 [査読有り][通常論文] Mechanical problems, common in large mining equipment, result in serious losses in operations efficiency and financial return. In this study, a minimum number of sensors was applied on the side of two cylinders of a diesel engine in order to build an abnormality diagnostic system that detects anomalous engine behaviour at an early stage. The study investigates whether or not the misfiring of an engine cylinder can be detected through analysis of acceleration results using an aggregative learning method (ALM). The results show that, using ALM, distinctive differences could be observed in almost every cylinder except those farthest from the accelerometer.
A1 超音波反応場を利用したリチウムイオン電池用鉄系正極材料の設計大川 浩一, 中村 貴司, 中里 慎吾, 川村 洋平, 佐藤 峰夫ソノケミストリー討論会講演論文集 16 1 - 2 日本ソノケミストリー学会 2007年 The Olivine-type LiFePO_4 was prepared by sonochemical method starting from LiOH・H_2O, (NH_4)_2HPO_4 and FeSO_4・7H_2O. Ultrasonic irradiation upon the solution of raw materials was able to synthesize fine particles of LiFePO_4 and prohibit the conversion of Fe^<2+> to Fe^<3+> in the solution without using a reducing agent. The prepared LiFePO_4 was characterized by XRD and SEM. The shape of the sample was a globular structure and the particle size of that was homogeneous and under sub-micron. The temperature of the solution is an important factor to synthesis LiFePO_4 by the sonochemical reaction. Discharge behavior of LiFePO_4 synthesized sonochemical reaction at 60℃ of the solution temperature exhibited 113mAhg^<-1> in the range of 4.0-3.0V vs. Li/Li^+ at a current rate of 0.2C. The ultrasonic effects on the precipitation of the LiFePO_4 precursor in the solution are very complicated, but one of them may helps nucleation of the LiFePO_4 precursor as a consequence of the collision among solute raw materials.
A6 ソノケミストリーを用いたリチウムイオン二次電池用鉄系正極材料の合成大川 浩一, 中里 槙吾, 矢吹 順平, 川村 洋平, 有瀬 一郎, 上松 和義, 佐藤 峰夫ソノケミストリー討論会講演論文集 15 13 - 14 日本ソノケミストリー学会 2006年 At present, lithium cobalt oxides and lithium nickel oxides are mainly used as cathodes of lithium ion batteries. This is because these materials show very high battery performance. However, they are not suitable for large-scaled batteries such as hybrid vehicles, because they are expensive and poor in resources. We then focused on iron because it is cheaper and more abundant. Iron Phosphate (FeO_4) is one of the most interesting materials in Iron based materials so far because it shows a high discharge voltage of 3.5 volts. The theoretical capacity is 170mAh/g, which is sufficient enough compared to present materials being used as lithium ion batteries. The remarkable feature of FePO_4 is that it can be synthesized in air. Its treatment is very easy but the cycle performance shows poor. In this study, we have tried to obtain good cycle performance and improve discharge capacity of FePO_4 utilizing the sonochemical method. The sonochemical reaction was conducted under the irradiation of ultrasound power 200W and frequency 200kHz for 3hours. The crystalline phase was identified by powder X-ray diffraction. The cathode for the electrochemical characterization was made by mixing powders of the sample, acetylene black and PTFE in 70:25:5 weight ratio under Argon atmosphere. The cathode properties were measured in a galvanic cell with a nonaqueous electrolyte, a polypropylene separator and a Li metal anode. Charge/Discharge performances were evaluated at a current rate of 2C in the voltage range between 2 to 3.9 volts. The first discharge profile obtained for the sample heated at 700℃ is improved about 10% compared with a previous report's one. We could also obtain LiFePO_4 by the sonochemical method.
P18 リチウムイオン二次電池用鉄系正極材料Fe_3PO_7の超音波照射合成(ポスターセッション)中里 槙吾, 大川 浩一, 川村 洋平, 上松 和義, 佐藤 峰夫ソノケミストリー討論会講演論文集 15 81 - 82 日本ソノケミストリー学会 2006年 Iron is expected as a positive electrode material because of its large Clarke number. In this reason, we have been interesting in iron based materials and been studying. In this time we focused on Fe_3PO_7. The theoretical capacity as cathode is 777mAh/g. Its large capacity is very attractive to compare to present materials being used as lithium ion batteries (LiCoO_2: 274mAh/g, LiMn_2O_4: 148mAh/g). The literature shows that Fe_3PO_7 was prepared by the two-step solid-state reaction. At first stoichiometric amounts of Fe_2O_3 and (NH_4)_2HPO_4 powders are mixed and heated 950 degrees Celsius for 12hour to synthesize FePO_4. Fe_2O_3 and FePO_4 are mixed and preheated 950 degrees Celsius for 12hour and finally heated at 1050 degrees Celsius and finally Fe_3PO_7 is prepared. Fe_3PO_7 requires a lot of time and high sintered temperature. To improve these problems, we have been studying about an easily synthesis method of Fe_3PO_7. In this study, we used the sonochemical method and try to obtain Fe_3PO_7 by one step reaction.
Ultrasonic measurement system for detecting penetration of boulders by autocorrelation analysisY Kawamura, M Tsurushima, K Mizutani, M Ujihira, N Aoshima, S KuraokaJAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 44 6B 4364 - 4369 2005年06月 [査読有り][通常論文] An elastic impact wave method is used as a typical nondestructive test method to investigate the depth of boulder penetration. However, in the elastic impact wave method using, for example, a hammer, the discrimination of the reflection wave produced by minute cracks is difficult. Theoretically, if it becomes possible to input the vibration of an ultrasonic domain into artificial structures, such as a concrete and a boulder, with a strong amplitude, deeper investigation depth compared to the conventional way with a high precision will be attained. In this study, a concrete block, with a known size, which was, unlike boulders, not buried under ground, was used as a test piece in a basic experiment. As analysis methods, a wavelet analysis for checking the reflection wave and an autocorrelation analysis for identifying the time tag of the reflection wave were used. As a result, the reflection wave was detected in a down chirp signal from 50 kHz to 40 kHz.
Ultrasonic measurement system for detecting penetration of boulders by autocorrelation analysisY Kawamura, M Tsurushima, K Mizutani, M Ujihira, N Aoshima, S KuraokaJAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 44 6B 4364 - 4369 2005年06月 [査読有り][通常論文] An elastic impact wave method is used as a typical nondestructive test method to investigate the depth of boulder penetration. However, in the elastic impact wave method using, for example, a hammer, the discrimination of the reflection wave produced by minute cracks is difficult. Theoretically, if it becomes possible to input the vibration of an ultrasonic domain into artificial structures, such as a concrete and a boulder, with a strong amplitude, deeper investigation depth compared to the conventional way with a high precision will be attained. In this study, a concrete block, with a known size, which was, unlike boulders, not buried under ground, was used as a test piece in a basic experiment. As analysis methods, a wavelet analysis for checking the reflection wave and an autocorrelation analysis for identifying the time tag of the reflection wave were used. As a result, the reflection wave was detected in a down chirp signal from 50 kHz to 40 kHz.
Method of detecting reflection wave using corresponding wave difference analysis for ultrasonic measurement system to detect penetration of bouldersMamoru Tsurushima, Youhei Kawamura, Yu Ito, Koichi Mizutani, Senro Kuraoka, Masuyuki Ujihira, Nobuharu Aoshima12th International Congress on Sound and Vibration 2005, ICSV 2005 5 4286 - 4293 2005年 Presently, because of an economic efficiency or usability, nondestructive test is being used to evaluate the damage level and the size of the concrete structure. Ultrasonic and elastic impact wave methods are the current testing methods of nondestructive test. Authors have developed a new testing method which uses chirp signal of ultrasonic and auto-correlation analysis in order to measure the penetration of the boulder stone into the ground. In our past research, we have successfully presumed the length of 900mm long concrete block and the length of 1460mm long white granite almost identically when the AE transducer received the direct wave and the reflection wave separately. However, when the direct wave and the reflection wave were mixed, we were unable to presume the length from the obtained waveform. In this paper, under the obtained data were mixed the direct wave and the reflection wave, the way to read the arrival time of the reflection wave from the data is referred. Authors group invented the way to use difference of the output waveform from two receivers with which the distance from a transmitter differs. And the result of the experiment with the length of 900mm long concrete block is shown.
Study of improving the ultrasonic measurement system to detect penetration of boulders using the cepstrum analysisYouhei Kawamura, Mamoru Tsurushima, Yu Ito, Nobuharu Aoshima, Koichi Mizutani, Senro Kuraoka, Masuyuki Ujihira12th International Congress on Sound and Vibration 2005, ICSV 2005 5 4302 - 4309 2005年 [査読有り][通常論文] Ultrasonic and elastic impact wave methods are used as the typical prototype of measuring concrete objects without breaking them up. However, by using the ultrasonic method, the input is restricted to be very small. Therefore, only the shallow region of the object can be investigated. Also, it is a tedious job to analyze the reflection wave obtained from the elastic impact wave method because of the minute cracks existing throughout the object. It is also known that this test method might damage the object. Theoretically, if it becomes possible to input vibration of an ultrasonic domain into a concrete object with a high output directly, the depth of the object will be obtained with high precision. In this research, it is aimed to improve the already built ultrasonic investigation system, which uses the output vibration of the piezo-electric ceramics that is constructed by the arbitrary waveform of the high voltage. Here, the target is the length of a concrete test piece. However, unwanted mixed echoes will be present throughout the result of this procedure with the targeted echo to measure. Therefore the cepstrum analysis method is chose to be used. The cepstrum analysis method makes it possible to disregard the unwanted mixed echoes in the system and to only get the arrival time of the echo that has reached the targeted length of the test piece. It is a simple method that is applied to the power spectrum of the targeted wave, by taking the logarithm of it and transforming it to time dimension using the inverse Fourier transform. The end result shows the arrival time of the echo. The targeted length of the test piece can be obtained using this arrival time.
Study on the improvement of the credibility of rockfall simulation -direct measurement of acceleration applied to rockfallsSatoshi Yamachika, Youhei Kawamura, Masuyuki Ujihira, Nobuharu AoshimaProceedings of the 14th International Symposium on Mine Planning and Equipment Selection, MPES 2005 and the 5th International Conference on Computer Applications in the Minerals Industries, CAMI 2005 1403 - 1413 2005年 [査読有り][通常論文] For pertinent countermeasure of rockfalls, rockfall simulation was studied many times. Any rockfall simulation has not gotten consistency between the simulation result and real rockfall. There are a few causes. One is whether method of calculation used the simulation approaches the mechanics of real rockfall. Two is whether parameters using the calculation are assigned pertinent value. This study suggests direct measurement of rockfall's detail motion which as method of closuring of the problems. It would be possible to determine pertinent value in parameter by comparing the detail motion to calculation result. In this research, 3-demensional rockfall simulation developing in this laboratory is explained. Then the results of experiments on impact acceleration that applies to rockfalls are shown, and compared to calculational results obtained by collision model using this simulation.
DEM simulation of collapse in cutting of slopesYouhei Kawamura, Ken Ito, Tatsuo Sakakibara, Masayuki Ujihira, Nobuharu AoshimaProceedings of the 14th International Symposium on Mine Planning and Equipment Selection, MPES 2005 and the 5th International Conference on Computer Applications in the Minerals Industries, CAMI 2005 606 - 615 2005年 [査読有り][通常論文] The slope loses its stability in the process of cutting it, therefore causing the slope to collapse. The slope is cut when activities such as mining, civil work and removal of deposit are done. The slope collapse triggers dangerous accidents. In 1999, an accident of a mining face slope collapse have occurred in Yunicho, Hokkaido and a machinery operator lost his life. The gavel pit where this slope collapse occurred has a mined out area which is reclaimed during the winter season. In the process of reclamation of the mined out area, a lot of snow was mixed with backfill. It seemed that the slope collapse was caused by the water pressure of melted snow and the difference of density between the reclaimed area and the slope. In this research, it is aiming to identify the behavior and mechanism of the slope collapse using distinct element method (DEM). The slope collapse behavior caused by the difference of gravel properties was reproduced using by changing parameters of elements in the reclaimed area.
移動通信網を用いた重機用多気筒ディーゼルエンジンの失火気筒の予防診断川村 洋平, 氏平 増之, 青島 伸治, 伊藤 史人, アクメトフ ダウレン F.計測自動制御学会論文集 40 2 257 - 266 公益社団法人 計測自動制御学会 2004年02月29日 [査読有り][通常論文] A diesel engine with a misfiring cylinder is likely to break down in a short time when the engine is used without maintenance. The authors have developed a method of detecting the occurrence of cylinder misfiring and specifying the misfiring cylinder by using wavelet analysis and statistical analysis on the r.m.s. values of two kinds of acceleration waveforms. This detection method is considered superior to traditional methods, which require several accelerometers, especially in terms of simplicity. Since the devolopment of the method, research has been conducted on semi-automatic processing of measured signals and signal transmission from the worksite to a remote office. Field tests confirmed that 1×105 points of dynamic data could be transmitted through the mobile multimedia network within 15min, and the time for signal processing was within 15min. Final determination on the condition of a diesel engine in heavy machinery could be achieved within 30min. Shortened processing time is expected by improvement of the processing software.
Study on the detection of misfiring cylinder in a shipping multi cylinder diesel engine using aggregative learning methodY. Kawamura, M. Ujjhira, M. Nagayama, N. Aoshima, F. Ito, D. AkhmetovProceedings of the SICE Annual Conference 153 - 156 2004年 [査読有り][通常論文] In this study, a minimum number of sensors will be applied on the side of two cylinders on the diesel engine in order to build an abnormal diagnosis system which detects anomaly behavior at an early stage by analyzing the acceleration waveform using the ALM method. This measurement system can be applied to the ship afterwards and by using the satellite phone system to transfer the data, it will be possible to manage the state of the engine from an office on land without the usage of a personal computer system on board.
On Signal Transmission and Data Processing Rate for Remote Diagnosis of Heavy Excavation MachineryY. Kawamura, M. Ujihira, K. Higuchi, M. Komazaki, D. F. Akhmetov, F. ItoAustralasian Institute of Mining and Metallurgy Publication Series 1 251 - 256 2003年 [査読有り][通常論文] A diesel engine with a misfiring cylinder is likely to break down in a short time when the engine is used without maintenance, The authors have developed a method of detecting the occurrence of cylinder misfiring and specifying the misfiring cylinder by using wavelet analysis and statistical analysis on the root mean square (r.m.s.) values of two kinds of acceleration waveforms. This detection method is considered superior to traditional methods, which require several accelerometers, especially in terms of simplicity. Since the development of the method, research has been conducted on semi-automatic processing of measured signals and signal transmission from the worksite to a remote office. Field tests confirmed that 1 × 10 points of dynamic data could be transmitted through the mobile multimedia network within IS minutes, and the time for signal processing was within 15 minutes. Final determination on the condition of a diesel engine in heavy machinery could be achieved within 30 minutes. Shortened processing time is expected by improvement of the processing software. 5
Artificial Neural Network Approach for Evaluation of Weight of Fallen ObjectsF. Ito, D. F. Akhmetov, M. Komazaki, M. Yasuike, Y. Kawamura, M. UjihiraAustralasian Institute of Mining and Metallurgy Publication Series 1 47 - 53 2003年 [査読有り][通常論文] Remote monitoring of geological situation at distant regions with complicated relief, including reliable detection of the rock falls and estimation of the scale of accidents, is of great importance for practical needs. In the paper, vibration data, caused by fall of sample objects and registered by cable sensors, are processed and analysed in order to construct some measure for the indirect evaluation of weight of fallen objects. Nonlinear models, which based on artificial neural networks (ANN), are proposed for the signal presentation. To improve and simplify the learning and classification abilities of the whole system, the aggregative learning method (ALM) is implemented. ALM features relatively low memory and computational resources needed for the procedure realisation, especially for data classification (recall) stage, in compare to conventional methods. The validity and efficiency of the proposed approach are tested through its application for rock fall detection and weight evaluation system using cable sensors and mobile communication network. Classification abilities of the proposed approach are shown useful for estimation of the fallen object weight. Characterised with high computational efficiency and simple decision-making procedure, the derived method can be useful for simple and reliable real-time monitoring system design.
Applicability of the magnification equation of lens for slope surveyM. Ujihira, T. Hzuka, Y. Kawamura, M. KawakitaInternational Journal of Surface Mining, Reclamation and Environment 16 3 230 - 244 2002年09月 [査読有り][通常論文] Photography is often used in geological survey, mining engineering or civil engineering to measure the length or width of an object by placing another object such as a scale, a hammer or a cigarette box next to the object. But, it is difficult to place a scale nearby the object when the object is too far and high or too dangerous to get to. In this study, practical applicability of the magnification equation of lens for indirect calculation of the length of a photographed object was examined. From this study, it was found that the applicable distance for the use of the magnification equation of lens was 84 m, even when the focal length was 36mm, and that the applicable distance was more than 300 m with the lens focal length being longer than 100 mm. Moreover, falling behavior, impact load and energy of a rock fall could be calculated readily using obtained information from a photograph.
実機による多気筒ディーゼルエンジンの不燃気筒の判定に関する研究川村 洋平, 氏平 増之, 桐本 賢太, 緒方 純俊, 中村 祥一, 樋口 澄志資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan 118 5 399 - 406 一般社団法人 資源・素材学会 2002年06月25日 [査読有り][通常論文] As a motive power in heavy construction machineries including mining and various construction works, a multi-cylinders type of diesel engine is very often used because of its high cost performance. Steady maintaining of diesel engine's operation is substantial in view of economic demands and environmental concerns. To realize this, a practice of early diagnosis and early repair are essential. In our previous study using a V-12 type of diesel engine installed on a bench, we demonstrated that a misfiring cylinder could be detected by statistical analysis method using rms value of the acceleration waveforms measured on a single point of the engine block. In this paper, the same experimentation and analyses as in the previous study were conducted for two practical machineries that loaded the same type engine of the previous study. Even though the engine was loaded on a practical machinery, it was found that a misfiring cylinder could be detected by the same way as in the previous study. In addition to the analyzing method in the previous study, in this study, we employed a wavelet transform method with the Gabor function as a window, and analyzed the acceleration waveforms. The results of wavelet analysis revealed that a misfiring cylinder could be detected visually from time-frequency charts. With the aid of statistical analysis using rms value, a misfiring cylinder in a multi-cylinder diesel engine can be doubly checked by wavelet analysis.
建設機械用多気筒ジーゼルエンジンにおける不燃気筒の予防診断桐本 賢太, 川村 洋平, 氏平 増之, 緒方 純俊計測自動制御学会論文集 = Transactions of the Society of Instrument and Control Engineers 38 2 230 - 232 計測自動制御学会 2002年02月28日 [査読有り][通常論文]
多気筒ディーゼルエンジンの不燃気筒の判定に関する研究 - 加速度波形のrms値を用いた場合 -川村 洋平, 氏平 増之, 樋口 澄志, 中村 祥一, 駒崎 征明, 伊藤 忠人資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan 117 6 485 - 493 一般社団法人 資源・素材学会 2001年06月25日 [査読有り][通常論文] Big scale construction machinery is absolutely necessary for the mineral resources development and various construction works. Troubles of the machinery give serious losses in the efficiency of operations and also in financial proceeds. In this meaning, machinery maintenance is very important for mining and construction works. Early diagnosis of the machinery is especially important to prevent a serious damage. Recently, diesel engine applied to excavation machinery are highly improved not to discharge exhaust gases of high concentration and to achieve high energy efficiency. However, a diesel engine involving non combustion cylinder has high probability to breakdown in a short time when the engine is used without any maintenance works. In this study, autocovariance of acceleration waves of cylinder block was calculated to obtain the period of revolution, and the combustion period of each cylinder was determined. Then rms value corresponding to each combustion period was calculated. Probability of overlapped area of two curves of normal distribution, which were obtained from rms values of normal and non combustion states respectively, was calculated. It was confirmed that non combustion cylinder of a diesel engine of V-12 type could be judged clearly using the relative intensity curve of the probability. This judgement method is considered to be superior to traditional methods where more than several numbers of accelerometers were used, especially from the viewpoint of simplicity.
Practical applicability of steel wire cable sensor for rock fall detectionM Ujihira, F Ito, T Tokunaga, Y Kawamura, S Konno, K Higuchi, M KomazakiMINE PLANNING AND EQUIPMENT SELECTION 2001 57 - 62 2001年 [査読有り][通常論文] Authors have studied the rock fall prediction system for these several years, in which cable sensor for vibration detection and mobile multimedia network are applied. It was confirmed from field tests that the newly developed steel wire cable sensor, which was installed along an unstable slope in grid pattern, could detect the falling impact even when the weight of a block was 200g and the falling trajectory could be judged from the gap of rise time of wave forms of 9 strings of the sensors stretched in horizontal direction. Topographic figure which was drawn by using the products of amplitudes of wave forms of horizontal and longitudinal steel wire cable sensors could give the falling trajectory visually. We have concluded that the steel wire cable sensor was useful to monitor the instability of the slope.
Evaluation of the weight of fallen object using the wave forms measured by cable sensor and mobile multimedia network systemF Ito, S Tsukazawa, M Komazaki, M Ujihira, Y Kawamura, T TokunagaMINE PLANNING AND EQUIPMENT SELECTION 2001 755 - 760 2001年 [査読有り][通常論文] Frequency monitoring of small rock fall events is a strong method to predict a slope failure or a rock fall of big scale along the slopes of traffic route and open pit mine. As a monitoring system, authors have proposed a remote monitoring system using cable sensor and mobile multimedia network. Frequency distribution or accumulated curve of rock fall events can be monitored using this system. However, it was very difficult to evaluate the weight of a fallen rock of each event, although the scale of the rock fall could serve us the important information to predict the failure in succession from the rock fall event. For the evaluation of the rock fall scale preceded a slope failure, authors had discussed and judged that wave forms measured by the detection system should be analyzed not only by using amplitude characteristics of output wave forms but also by using the spectrum characteristics in frequency domain. In this paper, it is described that integrated Fourier spectrum and integrated wave forms of acceleration and output voltage of cable sensor are particularly useful to evaluate the weight of fallen object.
A study on the detection of non-combustion cylinder of the diesel engine for construction machinery using wavelet analysisY Kawamura, M Ujihira, K Higuchi, K Kirimoto, M Komazaki, F ItoMINE PLANNING AND EQUIPMENT SELECTION 2001 167 - 172 2001年 [査読有り][通常論文] A diesel engine involving non-combustion cylinder has high probability to bred in a short time when the engine is used without any maintenance works. In this study, r.m.s. value corresponding to each combustion period of cylinders of diesel engine was calculated. Probability of overlapped area of two curves of normal distribution, which were obtained from r.m.s. values of normal and non-combustion states respectively, was calculated. It was confirmed that non-combustion cylinder of a diesel engine of V-12 type could be judged clearly using the relative intensity curve of the probability. Moreover, wavelet analysis for acceleration wave curves was carried out. It is concluded that almost of all non-combustion states of cylinders could be detected, also performing wavelet analysis for acceleration wave curves of cylinder block.
Practical applicability of steel wire cable sensor for rock fall detectionM Komazaki, K Hirama, F Ito, M Ujihira, Y Kawamura, T TokunagaMINE PLANNING AND EQUIPMENT SELECTION 2000 309 - 313 2000年 [査読有り][通常論文] Authors propose a monitoring system using cable sensor for rock collapse and fall detection. Practical applicability of this prediction system for concrete structures such as rock-shed or inlets of tunnels had been already confirmed, stretching the sensors in grid pattern to the internal surface of the structures. The tensile strength of cable sensor (CS) is 40 - 50 kg, and not enough for usage under real environmental conditions. For this reason, a steel wire type cable sensor (SWCS) is proposed. Here, a field test of SWCS for practical applicability for rock fall detection was carried out and the following points were made clearly: 1) The output signal level of SWCS is lower than that of CS. However, the sensitivity of SWCS is enough for practical use. 2) The falling trajectory of a rock was visually estimated from topographic method of the output voltage of SWCS. Therefore, SWCS could be recommended for practical use.
Practical applicability of steel wire cable sensor for rock fall detectionM Komazaki, K Hirama, F Ito, M Ujihira, Y Kawamura, T TokunagaMINE PLANNING AND EQUIPMENT SELECTION 2000 309 - 313 2000年 [査読有り][通常論文] Authors propose a monitoring system using cable sensor for rock collapse and fall detection. Practical applicability of this prediction system for concrete structures such as rock-shed or inlets of tunnels had been already confirmed, stretching the sensors in grid pattern to the internal surface of the structures. The tensile strength of cable sensor (CS) is 40 - 50 kg, and not enough for usage under real environmental conditions. For this reason, a steel wire type cable sensor (SWCS) is proposed. Here, a field test of SWCS for practical applicability for rock fall detection was carried out and the following points were made clearly: 1) The output signal level of SWCS is lower than that of CS. However, the sensitivity of SWCS is enough for practical use. 2) The falling trajectory of a rock was visually estimated from topographic method of the output voltage of SWCS. Therefore, SWCS could be recommended for practical use.
A field test of a rock fall detection system using cable sensor and mobile multimedia networkM. Komazaki, K. Hirama, M. Ujihira, S. Suzuki, H. Saeki, Y. KawamuraInternational Journal of Surface Mining, Reclamation and Environment 13 4 159 - 163 1999年 Cable sensor which is usually used for invader inspection of sensitive places such as atomic power stations and other high security buildings is considered to be available for rock noise and impact detection, because the sensor can detect vibration at any point of a string, and can be used with extending more than a hundred meter or more. From a field test using cable sensor and mobile multimedia network, it was found that the impact source caused by a steel ball dropping in the proximity of the sensing cable could be judged clearly from the order of rise time of signals of cable sensors, amplitudes of wave forms of signals and a topography pictured from peak values of signals transmitted by way of mobile multimedia network. This newly developed system is considered to be applicable not only to detect the resultant impact of fallen rocks but also to monitor the noise produced by the fracture of unstable rocks and sounds of falling rocks along a slope.
Applicability of the equation of image magnification of lens for rock engineeringM.Ujihira, T.Iizuka, Y.Kawamura, M.Kawakita, T.Tanabe, 川村, 洋平Proceeding of '99 Japan-Korea Joint Symposium on Rock Engneering 171-176 1999年 [査読有り][通常論文]
Study on output characteristics and mechanical strength of the cable sensor for vibration detectionM.Ujihira, Y.Kawamura, M.Sato, H.Konno, M.Komazaki, K.Hirama, 川村, 洋平Proceedings of the 8th Int. Symposium on Mine Planning and Equipment Selection 539-544 1999年 [査読有り][通常論文]
Rock fall detection system using cable sensor and mobile multimedia networkM Ujihira, S Ogawa, S Suzuki, S Hosoya, H Saeki, M Komazaki, K Hirama, M KawakitaMINE PLANNING AND EQUIPMENT SELECTION 1998 13 4 151 - 156 1998年 [査読有り][通常論文] Cable sensor which is usually used for invader inspection to the places such as atomic power stations and other buildings is considered to be available for rock noise and impact detection, because the sensor can detect vibration at any point of a string, and can be used with extending more than a hundred meter or more. From a field test using cable sensor and mobile multimedia network, it was found that the impact source caused by a steel ball dropping could be judged clearly from the order of rise time of signals of cable sensors, amplitudes of wave forms of signals and a topography pictured from peak values of signals transmitted by way of mobile multimedia network. This newly developed system is considered to be applicable not only to detect the resultant impact of fallen rocks but also to monitor the fracturing noises of unstable rocks and falling sounds of rocks along a slope.
