2-Stage Optimal Design and Analysis for Disassembly System with Environmental and Economic Parts Selection Using the Recyclability Evaluation Method

Igarashi, Kento,Yamada, Tetsuo,Inoue, Masato Korean Institute of Industrial Engineers 2014 Industrial Engineeering & Management Systems Vol.13 No.1

Promotion of a closed-loop supply chain requires disassembly systems that recycle end-of-life (EOL) assembled products. To operate the recycling disassembly system, parts selection is environmentally and economically carried out with non-destructive or destructive disassembly, and the recycling rate of the whole EOL product is determined. As the number of disassembled parts increases, the recycling rate basically increases. However, the labor cost also increases and brings lower profit, which is the difference between the recovered material prices and the disassembly costs. On the other hand, since the precedence relationships among disassembly tasks of the product also change with the parts selections, it is also required to optimize allocation of the tasks in designing a disassembly line. In addition, because information is required for such a design, the recycling rate, profit of each part and disassembly task times take precedence among the disassembly tasks. However, it is difficult to obtain that information in advance before collecting the actual EOL product. This study proposes and analyzes an optimal disassembly system design using integer programming with the environmental and economic parts selection (Igarashi et al., 2013), which harmonizes the recycling rate and profit using recyclability evaluation method (REM) developed by Hitachi, Ltd. The first stage involves optimization of environmental and economic parts selection with integer programming with ${\varepsilon}$ constraint, and the second stage involves optimization of the line balancing with integer programming in terms of minimizing the number of stations. The first and second stages are generally and mathematically formulized, and the relationships between them are analyzed in the cases of cell phones, computers and cleaners.

2 - Stage Optimal Design and Analysis for Disassembly System with Environmental and Economic Parts Selection Using the Recyclability Evaluation Method

Kento Igarashi, Tetsuo Yamada,Masato Inoue 대한산업공학회 2014 Industrial Engineeering & Management Systems Vol.13 No.1

Promotion of a closed-loop supply chain requires disassembly systems that recycle end-of-life (EOL) assembled products. To operate the recycling disassembly system, parts selection is environmentally and economically carried out with non-destructive or destructive disassembly, and the recycling rate of the whole EOL product is determined. As the number of disassembled parts increases, the recycling rate basically increases. However, the labor cost also increases and brings lower profit, which is the difference between the recovered material prices and the disassembly costs. On the other hand, since the precedence relationships among disassembly tasks of the product also change with the parts selections, it is also required to optimize allocation of the tasks in designing a disassembly line. In addition, because information is required for such a design, the recycling rate, profit of each part and disassembly task times take precedence among the disassembly tasks. However, it is difficult to obtain that information in advance before collecting the actual EOL product. This study proposes and analyzes an optimal disassembly system design using integer programming with the environmental and economic parts selection (Igarashi et al., 2013), which harmonizes the recycling rate and profit using recyclability evaluation method (REM) developed by Hitachi, Ltd. The first stage involves optimization of environmental and economic parts selection with integer programming with ε constraint, and the second stage involves optimization of the line balancing with integer programming in terms of minimizing the number of stations. The first and second stages are generally and mathematically formulized, and the relationships between them are analyzed in the cases of cell phones, computers and cleaners.

Logic circuit design for high-speed computing of dynamic response in real-time hybrid simulation using FPGA-based system

Igarashi, Akira Techno-Press 2014 Smart Structures and Systems, An International Jou Vol.14 No.6

One of the issues in extending the range of applicable problems of real-time hybrid simulation is the computation speed of the simulator when large-scale computational models with a large number of DOF are used. In this study, functionality of real-time dynamic simulation of MDOF systems is achieved by creating a logic circuit that performs the step-by-step numerical time integration of the equations of motion of the system. The designed logic circuit can be implemented to an FPGA-based system; FPGA (Field Programmable Gate Array) allows large-scale parallel computing by implementing a number of arithmetic operators within the device. The operator splitting method is used as the numerical time integration scheme. The logic circuit consists of blocks of circuits that perform numerical arithmetic operations that appear in the integration scheme, including addition and multiplication of floating-point numbers, registers to store the intermediate data, and data busses connecting these elements to transmit various information including the floating-point numerical data among them. Case study on several types of linear and nonlinear MDOF system models shows that use of resource sharing in logic synthesis is crucial for effective application of FPGA to real-time dynamic simulation of structural response with time step interval of 1 ms.

Exploratory Methods for Joint Distribution Valued Data and Their Application

Igarashi, Kazuto,Minami, Hiroyuki,Mizuta, Masahiro The Korean Statistical Society 2015 Communications for statistical applications and me Vol.22 No.3

In this paper, we propose hierarchical cluster analysis and multidimensional scaling for joint distribution valued data. Information technology is increasing the necessity of statistical methods for large and complex data. Symbolic Data Analysis (SDA) is an attractive framework for the data. In SDA, target objects are typically represented by aggregated data. Most methods on SDA deal with objects represented as intervals and histograms. However, those methods cannot consider information among variables including correlation. In addition, objects represented as a joint distribution can contain information among variables. Therefore, we focus on methods for joint distribution valued data. We expanded the two well-known exploratory methods using the dissimilarities adopted Hall Type relative projection index among joint distribution valued data. We show a simulation study and an actual example of proposed methods.

"Inhabitant" or "Resident" : Japan's Metropolises at the Crossroads

Igarashi, Akio Seoul City University 1996 SEOUL metropolitan FORA 96 Vol.1996 No.-

Between twenty and thirty kilometers northeast of the heart of Tokyo, the three cities of "Urawa, Yono, and Omiya run south to north from Tokyo's border. These three cities, which run contiguously from the northern side of Tokyo, from the heart of Saitama Prefecture. Urawa, with a population of 440,000 and area of 70 square kilometers, is the prefectural seat. Omiya, with a population of 420,000 and area of 89 square kilometers is and important center with extensive industry and transportation Yono, a small town sandwiched between these larger cities, has a population of 80,000 and an area of little more than eight square kilometers.

Influence of Machining on Magnetic Properties of Soft Magnetic Composites

Igarashi Kazunori,Miyahara Masahisa,Morimoto Koichiro 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

Influences of machining on magnetic properties of soft magnetic composites (SMC's) with addition of two kinds of binder, i.e., organic binder and inorganic one, were investigated. Machining does not affect DC magnetic properties of the SMC compacts. This can be ascribed to their particular structure in which the ironpowder particles are highly isolated by the binder. On the other hand, decrease in resistivity and resultant increase in eddy current loss was confirmed in the machined compacts containing inorganic binder. It is supposed that the brittleadditive binder existing between the iron particles is partly broken, and iron-to-iron contact is formed on the machined surface.

Inter-observer reliability in cone-beam computed tomography assessment of the retromolar canal: A practical plan to improve diagnostic imaging

Igarashi, Chinami,Theramballi, Yeshoda Ganesh,Kobayashi, Kaoru Korean Academy of Oral and Maxillofacial Radiology 2022 Imaging Science in Dentistry Vol.52 No.-

Purpose: This study aimed to investigate inter-observer reliability among observers with different levels of proficiency and the diagnostic imaging reliability of cone-beam computed tomography (CBCT) images of the retromolar canal. Materials and Methods: CBCT images of 307 patients were assessed for the presence of retromolar canals(RMCs) by 3 observers independently. Diagnoses were made twice by each observer at intervals of more than 3 weeks. Interobserver reliability was assessed using the kappa coefficient. One observer had no experience in diagnosis using CBCT images. Therefore, a specialist in diagnostic imaging explained the CBCT images for interpretation and practiced diagnostic imaging together with this observer, while the other observer interpreted the images independently. Thereafter, the observers re-evaluated the images. Results: The interobserver kappa coefficients (including bilateral RMCs) calculated at the first reading were low, ranging from 0.21 to 0.61. Their values ranged from 0.95 (right side) to 1.00 (left side) after one-on-one practice with a diagnostic imaging specialist, while the values ranged from 0.65 (right side) to 0.66 (left side) without one-on-one practice. Conclusion: Diagnostic accuracy was improved through diagnostic imaging practice. To improve the anatomical interpretation of images, it is important to practice diagnostic imaging with a specialist in diagnostic imaging. One-on-one instruction about diagnostic imaging was an effective method of training.

THE REPUBLICAN BASE OF AMERICAN DEMOCRACY : THE ORIGINS OF AMERICAN DEMOCRACY RECONSIDERED

IGARASHI, Takeshi 한국아메리카학회 1986 美國學論集 Vol.17 No.-

Inter-observer reliability in cone-beam computed tomography assessment of the retromolar canal: A practical plan to improve diagnostic imaging

Igarashi Chinami,Theramballi Yeshoda Ganesh,Kobayashi Kaoru 대한영상치의학회 2022 Imaging Science in Dentistry Vol.52 No.2

Purpose: This study aimed to investigate inter-observer reliability among observers with different levels of proficiency and the diagnostic imaging reliability of cone-beam computed tomography (CBCT) images of the retromolar canal. Materials and Methods: CBCT images of 307 patients were assessed for the presence of retromolar canals (RMCs) by 3 observers independently. Diagnoses were made twice by each observer at intervals of more than 3 weeks. Inter- observer reliability was assessed using the kappa coefficient. One observer had no experience in diagnosis using CBCT images. Therefore, a specialist in diagnostic imaging explained the CBCT images for interpretation and practiced diagnostic imaging together with this observer, while the other observer interpreted the images independently. Thereafter, the observers re-evaluated the images. Results: The interobserver kappa coefficients (including bilateral RMCs) calculated at the first reading were low, ranging from 0.21 to 0.61. Their values ranged from 0.95 (right side) to 1.00 (left side) after one-on-one practice with a diagnostic imaging specialist, while the values ranged from 0.65 (right side) to 0.66 (left side) without one-on-one practice. Conclusion: Diagnostic accuracy was improved through diagnostic imaging practice. To improve the anatomical interpretation of images, it is important to practice diagnostic imaging with a specialist in diagnostic imaging. One-on- one instruction about diagnostic imaging was an effective method of training.

Subliminal Calibration for Machine Operation Systems

Hiroshi Igarashi 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

Optimum human-machine operation is defined as when a operated machine with “human calculated dynamics model” coincides with its “machine dynamics.” Based on this definition, we propose calibration that brings the machine dynamics closer to the human-calculated machine model. Operators tend to learn dynamics without awareness during machine operation, so changes in machine dynamics appear to pose problems that both make operators uncomfortable and hinder their learning. We propose calibration for changes in machine dynamics without operator awareness, by quantifying perception based on cognitive scientific knowledge. We applied this calibration to a task involving the maneuvering of a mobile vehicle.