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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 28, Issue 4 - Dec 2002
Volume 28, Issue 3 - Sep 2002
Volume 28, Issue 2 - Jun 2002
Volume 28, Issue 1 - Mar 2002
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Performance Evaluation of a Multi - Item Production System Operated by the CONWIP Control Mechanism
Park, Chan-Woo ; Lee, Hyo-Seong ; Kim, Chang-Gon ;
Journal of Korean Institute of Industrial Engineers, volume 28, issue 1, 2002, Pages 1~13
We study a multi-component production/inventory system in which individual components are made to meet various demand types. We assume that the demands arrive according to a Poisson process, but there is a fixed probability that a demand requests a particular kit of different components. Each component is produced by a flow line with several stations. The production of each component is operated by the CONWIP control mechanism. To analyse this system, we propose an approximation method based on aggregation method. In application of the aggregation method, a product-form approximation technique as well as a matrix-geometric method is used. Comparisons with simulation show that the approximation method provides fairly good results.
Study on the Resource Allocation Planning of Container Terminal
Jang, Yang-Ja ; Jang, Seong-Yong ; Yang, Chang-Ho ; Park, Jin-Woo ;
Journal of Korean Institute of Industrial Engineers, volume 28, issue 1, 2002, Pages 14~24
We focus on resource allocation planning in container terminal operation planning problems and present network design model and genetic algorithm. We present a network design model in which arc capacities must be properly dimensioned to sustain the container traffic. This model supports various planning aspects of container terminal and brings in a very general form. The integer programming model of network design can be extended to accommodate vertical or horizontal yard configuration by adding constraints such as restricting the sum of yard cranes allocated to a block of yards. We devise a genetic algorithm for the network design model in which genes have the form of general integers instead of binary integers. In computational experiments, it is found that the genetic algorithm can produce very good solution compared to the optimal solution obtained by CPLEX in terms of computation time and solution quality. This algorithm can be used to generate many alternatives of a resource allocation plan for the container terminal and to evaluate the alternatives using various tools such as simulation.
Obstacle Avoidance for a Mobile Robot Using Optical Flow
Lee, Han-Sik ; Baek, Jun-Geol ; Jang, Dong-Sik ;
Journal of Korean Institute of Industrial Engineers, volume 28, issue 1, 2002, Pages 25~35
This paper presents a heuristic algorithm that a mobile robot avoids obstacles using optical flow. Using optical flow, the mobile robot can easily avoid static obstacles without a prior position information as well as moving obstacles with unknown trajectories. The mobile robot in this paper is able to recognize the locations or routes of obstacles, which can be detected by obtaining 2-dimensional optical flow information from a CCD camera. It predicts the possibilities of crash with obstacles based on the comparison between planned routes and the obstacle routes. Then it modifies its driving route if necessary. Driving acceleration and angular velocity of mobile robot are applied as controlling variables of avoidance. The corresponding simulation test is performed to verify the effectiveness of these factors. The results of simulation show that the mobile robot can reach the goal with avoiding obstacles which have variable routes and speed.
Analysis of the M/G
/1 Queue by the Arrival Time Approach
Chae, Kyung-Chul ; Chang, Seok-Ho ; Lee, Ho-Woo ;
Journal of Korean Institute of Industrial Engineers, volume 28, issue 1, 2002, Pages 36~43
We analyze bulk service
queues using the arrival time approach of Chae et al. (2001). As a result, the decomposition property of the M/G/1 queue with generalized vacations is extended to the
queue in which the batch size is exactly a constant b. We also demonstrate that the arrival time approach is useful for relating the time-average queue length PGF to that of the departure time, both for the
queue in which the batch size is as big as possible but up to the maximum of constant b. The case that the batch size is a random variable is also briefly mentioned.
A Risk Management Model for Efficient Domestic Information Technology Security
Ahn, Choon-soo ; Cho, Sung-Ku ;
Journal of Korean Institute of Industrial Engineers, volume 28, issue 1, 2002, Pages 44~56
For the risk analysis and risk assessment techniques to be effectively applied to the field of information technology (IT) security, it is necessary that the required activities and specific techniques to be applied and their order of applications are to be determined through a proper risk management model. If the adopted risk management model does not match with the characteristics of host organization, an inefficient management of security would be resulted. In this paper, a risk management model which can be well adapted to Korean domestic IT environments is proposed for an efficient security management of IT. The structure and flow of the existing IT-related risk management models are compared and analysed, and their common and/or strong characteristics are extracted and incorporated in the proposed model in the light of typical threat types observed in Korean IT environments.
Simulated Annealing for Reduction of Defect Sensitive Area Through Via Moving
Lee, Seung Hwan ; Sohn, So Young ;
Journal of Korean Institute of Industrial Engineers, volume 28, issue 1, 2002, Pages 57~62
The semiconductor industry has continuously been looking for the ways to improve yield and to reduce manufacturing cost. The layout modification approach, one of yield enhancement techniques, is applicable to all design styles, but it does not require any additional resources in terms of silicon area. The layout modification method for yield enhancement consists of making local variations in the layout of some layers in such a way that the critical area, and consequently the sensitivity of the layer to point defects, is reduced. Chen and Koren (1995) proposed a greedy algorithm that removes defect sensitive area using via moving, but it is easy to fall into a local minimum. In this paper, we present a via moving algorithm using simulated annealing and enhance yield by diminishing defect sensitive area. As a result, we could decrease the defect sensitive area effectively compared to the greedy algorithm presented by Chen and Koren. We expect that the proposed algorithm can make significant contributions on company profit through yield enhancement.
Short-Term Forecasting of Monthly Maximum Electric Power Loads Using a Winters' Multiplicative Seasonal Model
Yang, Moonhee ; Lim, Sanggyu ;
Journal of Korean Institute of Industrial Engineers, volume 28, issue 1, 2002, Pages 63~75
To improve the efficiency of the electric power generation, monthly maximum electric power consumptions for a next one year should be forecasted in advance and used as the fundamental input to the yearly electric power-generating master plan, which has a greatly influence upon relevant sub-plans successively. In this paper, we analyze the past 22-year hourly maximum electric load data available from KEPCO(Korea Electric Power Corporation) and select necessary data from the raw data for our model in order to reflect more recent trends and seasonal components, which hopefully result in a better forecasting model in terms of forecasted errors. After analyzing the selected data, we recommend to KEPCO the Winters' multiplicative model with decomposition and exponential smoothing technique among many candidate forecasting models and provide forecasts for the electric power consumptions and their 95% confidence intervals up to December of 1999. It turns out that the relative errors of our forecasts over the twelve actual load data are ranged between 0.1% and 6.6% and that the average relative error is only 3.3%. These results indicate that our model, which was accepted as the first statistical forecasting model for monthly maximum power consumption, is very suitable to KEPCO.
Hybrid Genetic Algorithm Reinforced by Fuzzy Logic Controller
Yun, Young-Su ;
Journal of Korean Institute of Industrial Engineers, volume 28, issue 1, 2002, Pages 76~86
In this paper, we suggest a hybrid genetic algorithm reinforced by a fuzzy logic controller (flc-HGA) to overcome weaknesses of conventional genetic algorithms: the problem of parameter fine-tuning, the lack of local search ability, and the convergence speed in searching process. In the proposed flc-HGA, a fuzzy logic controller is used to adaptively regulate the fine-tuning structure of genetic algorithm (GA) parameters and a local search technique is applied to find a better solution in GA loop. In numerical examples, we apply the proposed algorithm to a simple test problem and two complex combinatorial optimization problems. Experiment results show that the proposed algorithm outperforms conventional GAs and heuristics.
Comparison and Analysis of Competition Strategies in Competitive Coevolutionary Algorithms
Kim, Yeo Keun ; Kim, Jae Yun ;
Journal of Korean Institute of Industrial Engineers, volume 28, issue 1, 2002, Pages 87~98
A competitive coevolutionary algorithm is a probabilistic search method that imitates coevolution process through evolutionary arms race. The algorithm has been used to solve adversarial problems. In the algorithms, the selection of competitors is needed to evaluate the fitness of an individual. The goal of this study is to compare and analyze several competition strategies in terms of solution quality, convergence speed, balance between competitive coevolving species, population diversity, etc. With two types of test-bed problems, game problems and solution-test problems, extensive experiments are carried out. In the game problems, sampling strategies based on fitness have a risk of providing bad solutions due to evolutionary unbalance between species. On the other hand, in the solution-test problems, evolutionary unbalance does not appear in any strategies and the strategies using information about competition results are efficient in solution quality. The experimental results indicate that the tournament competition can progress an evolutionary arms race and then is successful from the viewpoint of evolutionary computation.
A Method of Sensitivity Analysis for the Infeasible Interior Point Method When a Variable is Added
Kim, Woo-Je ; Park, Chan-kyoo ; Lim, Sungmook ; Park, Soondal ; Murty , Katta G. ;
Journal of Korean Institute of Industrial Engineers, volume 28, issue 1, 2002, Pages 99~104
This paper presents a method of sensitivity analysis for the infeasible interior point method when a new variable is introduced. For the sensitivity analysis in introducing a new variable, we present a method to find an optimal solution to the modified problem. If dual feasibility is satisfied, the optimal solution to the modified problem is the same as that of the original problem. If dual feasibility is not satisfied, we first check whether the optimal solution to the modified problem can be easily obtained by moving only dual solution to the original problem. If it is possible, the optimal solution to the modified problem is obtained by simple modification of the optimal solution to the original problem. Otherwise, a method to set an initial solution for the infeasible interior point method is presented to reduce the number of iterations required. The experimental results are presented to demonstrate that the proposed method works better.
Performance Analysis of Heuristic Algorithms for Consolidated Transportation with Weight and Volume Constraints
Rim, Suk-Chul ; Yoo, Youngjin ;
Journal of Korean Institute of Industrial Engineers, volume 28, issue 1, 2002, Pages 105~111
When transporting multiple items by trucks of various size, one needs to assign a group of items to each truck so as to minimize the total cost, while meeting the weight and volume constraint of each truck. In this paper, we formulate the problem as an integer programming problem and propose four heuristic algorithms for the problem. Computer simulation is used to evaluate the average performance of the four heuristic algorithms for the consolidated transportation problem.
Pattern Selection Using the Bias and Variance of Ensemble
Shin, Hyunjung ; Cho, Sungzoon ;
Journal of Korean Institute of Industrial Engineers, volume 28, issue 1, 2002, Pages 112~127
A useful pattern is a pattern that contributes much to learning. For a classification problem those patterns near the class boundary surfaces carry more information to the classifier. For a regression problem the ones near the estimated surface carry more information. In both cases, the usefulness is defined only for those patterns either without error or with negligible error. Using only the useful patterns gives several benefits. First, computational complexity in memory and time for learning is decreased. Second, overfitting is avoided even when the learner is over-sized. Third, learning results in more stable learners. In this paper, we propose a pattern 'utility index' that measures the utility of an individual pattern. The utility index is based on the bias and variance of a pattern trained by a network ensemble. In classification, the pattern with a low bias and a high variance gets a high score. In regression, on the other hand, the one with a low bias and a low variance gets a high score. Based on the distribution of the utility index, the original training set is divided into a high-score group and a low-score group. Only the high-score group is then used for training. The proposed method is tested on synthetic and real-world benchmark datasets. The proposed approach gives a better or at least similar performance.