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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Korean Institute of Industrial Engineers
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Journal DOI :
Korean Institute of Industrial Engineers
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Volume & Issues
Volume 34, Issue 4 - Dec 2008
Volume 34, Issue 3 - Sep 2008
Volume 34, Issue 2 - Jun 2008
Volume 34, Issue 1 - Mar 2008
Selecting the target year
Effectiveness of an Exponentially Smoothed Ordering Policy as Compared with Kanban System
Tamura, Takayoshi ; Dhakar, Tej S. ; Ohno, Katsuhisa ;
Journal of Korean Institute of Industrial Engineers, volume 34, issue 1, 2008, Pages 1~12
The Kanban system in Just-In-Time (JIT) production is very effective in reducing the inventories when consumption rate of the final product is relatively stable. When large fluctuations exist in the consumption rate, a new production ordering policy in which the production order quantity is determined by smoothing the demands exponentially is more suitable. This new ordering policy has not been investigated sufficiently. In this research, a multi-stage production and inventory system with stock points for materials and finished items located at each stage is considered. Approximations of average inventories at each stage in the system are derived theoretically. Numerical simulations are carried out to assess the accuracy of approximations and to evaluate the effectiveness of the new ordering policy as compared with the Kanban system. As a result, it is shown that the new ordering policy can achieve significantly lower inventory costs than the original Kanban system. The new ordering policy thus emerges as a key concept for an effective supply chain management.
Telecommunication Network Optimization Current Status and Challenges
Park, Kyungchul ; Lee, Heesang ;
Journal of Korean Institute of Industrial Engineers, volume 34, issue 1, 2008, Pages 13~22
This paper gives reviews on current research status in telecommunication network design. Two problems are identified as major research issues. One is the WDM network design problem, where traffic grooming, virtual topology design and routing and wavelength assignment problems are considered. The other is the OSPF weight setting problem which was proposed as a practical method to implement traffic engineering capability in IP networks. After presenting surveys on those problems, we discuss potential challenging research issues in telecommunication network design.
Design of Accelerated Degradation Test with Tightened Critical Values under Random Coefficient Degradation Rate Model
Cho, You-hee ; Seo, Sun-keun ;
Journal of Korean Institute of Industrial Engineers, volume 34, issue 1, 2008, Pages 23~31
This paper presents accelerated degradation test plans considering adoption of tightened critical values. Under arandom coefficient degradation rate and log-linear acceleration models, the asymptotic variance of an estimatorfor a lifetime quantile at the use condition as the optimization criterion is derived where the degradation ratefollows a lognormal and Reciprocal Weibull distributions, respectively and then the low stress level andproportions ofunits allocated to each stress level are determined. We also show that the developed test plans canbe applied to the multiplicative model with measurement error.
An improved Ordering and Recovery Policy for Reusable Items
Jung, Jin-A ; Koh, Shie-Gheun ;
Journal of Korean Institute of Industrial Engineers, volume 34, issue 1, 2008, Pages 32~41
This paper studies a joint EOQ and EPQ model in which a stationary demand can be satisfied by recycled products as well as newly purchased products. The model assumes that a fixed quantity of the used products are collected from customers and later recovered for reuse. The recovered products are regarded as perfectly new ones. We also assume that the number of orders for newly purchasing items and the number of recovery setups in a cycle can be mutually independent integers. Under these assumptions, we develop an optimization model obtaining the economic order quantity for newly procured products, the optimal lot size for the recovery process, and the sequence of the orders and the setups, simultaneously. And then a simple solution procedure to find a local optimal control parameter set is proposed. To validate the model and the solution procedure, finally, some computational experiments are presented.
Consistency Test in the House of Quality using Permutation Test
Kim, Kyungmee O. ;
Journal of Korean Institute of Industrial Engineers, volume 34, issue 1, 2008, Pages 42~48
The house of quality (HOQ) involves subjective and ambiguous information typically through a likert scale, It isimportant to validate consistency of such input in the HOQ before rating the fmal importance of technicalrequirements, Previously, a methodology was developed to test the consistency of relationship strengths in theHOQ between roof matrix and relationship matrix. We described disadvantages of the previous method andpropose a new approach based on the permutation test. Advantages of the proposed method are illustrated withan example.
Solution Methods for Reliability Optimization of a Series System with Component Choices
Kim, Ho-Gyun ; Bae, Chang-Ok ; Kim, Jae-Hwan ; Son, Joo-Young ;
Journal of Korean Institute of Industrial Engineers, volume 34, issue 1, 2008, Pages 49~56
Reliability has been considered as an important design measure in various industrial systems. We discuss a reliability optimization problem with component choices (ROP-CC) subject to a budget constraint. This problem has been known as a NP-hard problem in the reliability design fields. Several researchers have been working to find the optimal solution through different heuristic methods. In this paper, we describe our development of simulated annealing (SA) and tabu search (TS) algorithms and a reoptimization procedure of the two algorithms for solving the problem. Experimental results for some examples are shown to evaluate the performance of these methods. We compare the results with the solutions of a previous study which used ant system (AS) and the global optimal solution of each example obtained through an optimization package, CPLEX 9.1. The computational results indicate that the developed algorithms outperform the previous results.
Prediction of Postural Sagging Observed During Driving in Korean Male Drivers
Oh, Youngtaek ; Jung, Eui S. ; Park, Sungjoon ; Jeong, Seong Wook ;
Journal of Korean Institute of Industrial Engineers, volume 34, issue 1, 2008, Pages 57~65
In the vehicle design, the research on driving posture has stood out as one of the important issues. Recently, the research on 3D human modeling focused on more exact implementation of real driving posture. However, prediction of driving posture through the 3D human modeling fail to reflect on the model the phenomenon called sagging, which refers to the retraction or shrinking of the torso while driving. 30 male subjects participated in the experiment where total subjects were divided into four groups according to height percentile(under 50%ile, 51%ile to 75%ile, 76%ile to 95%ile, over 95%ile). The independent variables were seat back angle(4 levels) and seat pan angle(2 levels). The dependent variable was capacity or the degree of retraction of the torso. First this study measured the sagging capacity by using a paired T-test between erect and retracted posture. Secondly it was tried to find out significant anthropometric variables that were statistically correlated by the analysis of correlation. Finally, a prediction model was derived which explains the capacity of sagging.
Development of An Ergonomic Product Development Process Reflecting Quantified Customer Preference
Im, YoungJae ; Jung, Eui S. ; Park, SungJoon ;
Journal of Korean Institute of Industrial Engineers, volume 34, issue 1, 2008, Pages 66~78
In the past, Manufacturers used to determine the quality of products, but the trend of today's market becomesmore into customer-driven. As a result, demands from customers are becoming more diverse and complicated,and most companies are obligated to meet their needs. As one of the effort to achieve their satisfaction,companies are now emphasizing activities to find out what customers specifically want and extract voice ofcustomer(VOC). This study attempts to develop an ergonomic product development process as a method tomaximally reflect the VOC. In order to meet this goal, ergonomic design guidelines, which are possible to beclassified according that user's human characteristics, will be recommended. Even now, there are numerousdesign guidelines already existing in the ergonomics literature. However, it is not realistically feasible to reviewall of those guidelines, and some of them are even conflicting with each other. Therefore, in this paper, theproduct development process, which prioritizes the human characteristics that reflect customer needs and appliesthe design guidelines that meet the most important ones, will be suggested. Finally, the research was described toshow the validity of the product development process through an example of a mobile phone development case.
The Eco-Architecture for Optimal End-Of-Life Strategy for Complex Products : An Extension to Hierarchical Analysis
Kwak, Min Jung ; Lee, Hyun Bok ; Hong, Yoo Suk ; Cho, Nam Wook ; Choi, Keon Young ;
Journal of Korean Institute of Industrial Engineers, volume 34, issue 1, 2008, Pages 79~89
An end-of-life strategy is concerned with how to disassemble a product and what to do with each of the resultingdisassembled parts. A sound understanding of the end-of-life strategy at the early design stage could improve theease of disassembly and recycling in an efficient and effective manner. Therefore, the end-of-life decisionmaking for environmental conscious design has become a great concern to product manufacturers.We introduce a novel concept ofeco-architecture which represents a scheme by which the physical componentsare allocated to end-of-life modules. An end-of-life module is a physical chunk of connected components or afeasible subassembly which can be simultaneously processed by the same end-of-life option without furtherdisassembly. In this paper, a method for analyzing the eco-architecture of a product at the configuration designstage is proposed. It produces an optimal eco-architecture under the given environmental regulations. To dealwith the case ofa complex product, the method is extended for analyzing hierarchical eco-architecture.
Effects of Rear-Foot Wedged Insoles on the Foot Pressure in Walking
Ryu, Taebeum ; Chae, Byungkee ; Lim, Wansoo ; Choi, Hwa Soon ; Chung, Min K. ;
Journal of Korean Institute of Industrial Engineers, volume 34, issue 1, 2008, Pages 90~97
Wedged insoles are frequently used to reduce the pains caused by the knee arthritis or the foot overuse syndrome. The present study analyzed the effect of wedged rear-foot insoles on the foot pressure in walking. Three medially wedged insoles with three angles (5, 8 and 15") and three laterally wedged insoles with the same angles were made, and a flat insole were prepared. Ten healthy males in twenties walked in a specified line with each insole. Center of pressure (COP), relative vertical force and maximum force on anatomical areas were analyzed from the measured foot pressure data. At heel contact, medially wedged insoles significantly increased the pressure of the medial foot side (COP moved medially by 2-5 mm and maximum pressure of 1st metatarsal head increased by 110-120% relative to the flat insole), In contrast, laterally wedged insoles significantly increased the lateral side pressure (COP moved laterally by 1-5 mm and the ratio of
metatarsal head pressure to
metatarsal head increased by 0.5-2.0 relative to the flat insole). At toe off, both wedged insoles significantly increased the pressure of the medial foot side (COP moved medially by 0.5-10 mm and the ratio of
metatarsal head pressure to
metatarsal head increased by 2.0 relative to the flat insole). Especially, the laterally wedged insoles significantly increased the relative vertical force (6-12%) of the rear-foot more than the flat insole.
A Maintenance Design of Connected-(r, s)-out-of-(m, n) F System Using Simulated Annealing
Lee, Sangheon ; Kang, Youngtai ; Shin, Dongyeul ;
Journal of Korean Institute of Industrial Engineers, volume 34, issue 1, 2008, Pages 98~107
The purpose of this paper is to present an optimization scheme that aims at minimizing the expected cost per unittime. This study considers a linear connected-(r, s)-ouI-of-(m, n):f lattice system whose components are orderedlike the elements of a linear (m, n)-matrix. We assume that all components are in the state 1 (operating) or 0(failed) and identical and s-independent. The system fails whenever at least one connected (r, s)-submatrix offailed components occurs. To find the optimal threshold of maintenance intervention, we use a simulatedannealing(SA) algorithm for the cost optimization procedure. The expected cost per unit time is obtained byMonte Carlo simulation. We also has made sensitivity analysis to the different cost parameters. In this study,utility maintenance model is constructed so that minimize the expense under full equipment policy throughcomparison for the full equipment policy and preventive maintenance policy. The full equipment cycle and unitcost rate are acquired by simulated annealing algorithm. The SA algorithm is appeared to converge fast inmulti-component system that is suitable to optimization decision problem.
Study on Dispatching with Quality Assurance
Ko, Hyo-Heon ; Kim, Jihyun ; Baek, Jun-Geol ; Kim, Sung-Shick ;
Journal of Korean Institute of Industrial Engineers, volume 34, issue 1, 2008, Pages 108~121
Dispatching rule for parallel machines with multi product is proposed in this paper, In current market,customer's request for higher quality is increasing, In accordance with such demand, manufacturers are focusingon improving the quality of the products. Such shift in production objective is risky. The possibility ofneglecting another important factor in customer satisfaction increases, namely due dates. From the aspect ofimproving quality, frequency of product assignment to limited number of high performance machines willincrease. This will lead to increased waiting time which can incur delays, In the case of due date orientedproduct dispatch, Products are assigned to machines without consideration for quality. Overall deterioration ofproduct quality is inevitable, In addition, Poor products will undergo rework process which can increase delays.The objective of this research is dispatching products to minimize due date delays while improving overallquality. Quality index is introduced to provide means of standardizing product quality. The index is used toassure predetermined quality level while minimizing product delays when dispatching products. Qualitystandardization method and dispatching algorithm is presented. And performance evaluation is performed withcomparison to various dispatching methods.