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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 29, Issue 4 - Dec 2003
Volume 29, Issue 3 - Sep 2003
Volume 29, Issue 2 - Jun 2003
Volume 29, Issue 1 - Mar 2003
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2-Approximation Algorithm for Parallel Machine Scheduling with Consecutive Eligibility
Hwang, Hark-Chin ; Kim, Gyutai ;
Journal of Korean Institute of Industrial Engineers, volume 29, issue 3, 2003, Pages 190~196
We consider the problem of scheduling n jobs on m machines with the objective of minimizing makespan. Each job cannot be eligible to all the machines but to its consecutively eligible set of machines. For this problem, a 2-approximation algorithm, MFFH, is developed. In addition, an example is presented to show the tightness of the algorithm.
The Influences of Reading Type, Line Length, and Interlinear Spacing on the Legibility of Korean Web Documents
Shin, Jong-Hyun ; Park, Min-Yong ;
Journal of Korean Institute of Industrial Engineers, volume 29, issue 3, 2003, Pages 197~205
Many people get plenty of information from World Wide Web, and the study of the factors that affect on reading task on web browser is presenting important issue. But domestic studies on legibility of Korean on web environment were relatively poor and the study about suitable text layout for skimming wasn't carried out also. At this point, this study was performed to investigate the effects of two types of reading, three levels of line length, and three levels of interlinear spacing on comprehension and reading rate when subjects read the materials on web browser. Reading speed, error rate, subjective preference and SACL(Stress and Arousal Checklist) evaluation were measured to evaluate the effects. Eighteen volunteer subjects participated in eighteen web document sessions with two different reading types, three different line lengths, and three different interlinear spacings. Statistical results from objective and subjective evaluations indicate that 50 characters per line of line length and 100 percents of interlinear spacing improved reading rate, overall error rates were reduced when reading normally, and SACL measures were increased at fast reading type. Consequently, in order to design text layout to retrieve information in WWW environment effectively, just applying guidelines of traditional printed material is not proper. Therefore, it is effective to consider reading type, line length, and interlinear spacing. Implications of these results and suggestions for the further study are also addressed.
An Optimal Distribution Model under Consideration of Delivery Unit and Backlogging Costs
Lee, Yang Ho ; An, Joon-Hong ; Choi, Gyunghyun ;
Journal of Korean Institute of Industrial Engineers, volume 29, issue 3, 2003, Pages 206~212
In this paper, we propose a mathematical optimization model with a suitable algorithm to determine delivery and backlogging quantities by minimizing the total cost including the penalty costs for delay. The system has fixed transshipment costs and demands are fulfilled by some delivery units that represent the volume of delivery amount to be shipped in a single time period. Since, backlogging is allowed, demands could be delivered later at the expense of some penalty costs. The model provides the optimal decisions on when and how much to he delivered while minimizing the total costs. To solve the problem, we propose an algorithm that uses the Lagrangian dual in conjunction with some primal heuristic techniques that exploit the special structure of the problem. Finally, we present some computational test results along with comments on the further study.
A Part-Machine Grouping Algorithm Considering Alternative Part Routings and Operation Sequences
Baek, Jun-Geol ; Baek, Jong-Kwan ; Kim, Chang Ouk ;
Journal of Korean Institute of Industrial Engineers, volume 29, issue 3, 2003, Pages 213~221
In this paper, we consider a multi-objective part-machine grouping problem, in which part types have several alternative part routings and each part routing has a machining sequence. This problem is characterized as optimally determining part type sets and its corresponding machine cells such that the sum of inter-cell part movements and the sum of machine workload imbalances are simultaneously minimized. Due to the complexity of the problem, a two-stage heuristic algorithm is proposed, and experiments are shown to verify the effectiveness of the algorithm.
Analysis and Optimization of a 2-Class-based Dedicated Storage System
Yang, Moonhee ;
Journal of Korean Institute of Industrial Engineers, volume 29, issue 3, 2003, Pages 222~229
In this paper, we address a layout design problem, PTN, for determining an appropriate 2-class-based dedicated storage layout in a class of unit load storage systems. Our strong conjecture is that PTNI2] is NP-hard. Restricting PTN, we provide three solvable cases of PTN in which an optimal solution to the solvable cases is one of the partitions based on the PAI(product activity index)-nonincreasing ordering. However, we show with a counterexample that a solution based on the PAI-non increasing ordering does not always give an optimal solution to PTN. Utilizing the derived properties, we construct an effective heuristic algorithm for solving PTN based on a PAI-non increasing ordering with performance ratio bound. Our algorithm with O(
) is effective in the sense that it guarantees a better class-based storage layout than a randomized storage layout in terms of the expected single command travel time.
Configuration Design of a Train Bogie using Functional Decomposition and TRIZ Theory
Lee, Jangyong ; Han, Soonhung ;
Journal of Korean Institute of Industrial Engineers, volume 29, issue 3, 2003, Pages 230~238
The configuration design of a mechanical product can be efficiently performed when it is based on the functional modeling. There are methodologies, which decompose function from the abstract level to the concrete level and match the functions to physical parts. But it is difficult to carry out an innovative design when the function is matched only to a pre-detined part. This paper describes the configuration design process of a mechanical product with a design expert system, which uses function taxonomy and TRIZ theory. The expert system can propose a functional modeling of a new part. which is not in the existing parts list. The abstraction levels of design knowledge are introduced, which describe the operation of mechanical product in the levels of abstraction. This is the theoretical background of using knowledge of function and TRIZ for configuration design. The expert system is adequate to control this design knowledge. which expresses knowledge of functional modeling, mapping rules between functions and parts, selection of parts, and TRIZ theory. The hierarchy of functions and machine parts are properly expressed by classes and objects in the expert system. A design expert system has been implemented for the configuration design of a train bogie, and a new brake system of the bogie is introduced with the aid of TRIZ's 30 function groups.
Determination of Optimal Mean Value and Screening Limit for a Production Process with Logistic Function
Hong, Sung Hoon ;
Journal of Korean Institute of Industrial Engineers, volume 29, issue 3, 2003, Pages 239~246
Individual items are produced continuously from an industrial process. Each item is checked to determine whether it satisfies a lower screening limit for the quality characteristic which is the weight of an expensive ingredient. If it does, it is sold at a regular price; if it does not, it is reprocessed or sold at a reduced price. The process mean may be adjusted to a higher value in order to reduce the proportion of the nonconforming items. Using a higher process mean, however, may result in a higher production cost. In this paper, the optimal process mean and lower screening limit are determined in situations where the probability that an item functions well is given by a logistic function of the quality characteristic. Profit models are constructed which involve four price/cost components; selling prices, cost from an accepted nonconforming item, and reprocessing and inspection costs. Methods of finding the optimal process mean and lower screening limit are presented and numerical examples are given.
An Approximation of the M/G/1 System with Finite Workload Capacity
Lee, Hyung Joong ; Hur, Sun ;
Journal of Korean Institute of Industrial Engineers, volume 29, issue 3, 2003, Pages 247~252
We propose an approximation of the M/G/1 system with finite workload capacity, where those customers whose admission to the system would increase the workload beyond a prespecified finite capacity limit are not accepted. Our approximation method is based on the idea that the service time of a customer in the M/G/1 system can be approximated as the sum of service times of a batch of customers in the
system where the deterministic service time d is small enough. That is, the original service time is discretized and approximated by the batch size. We exemplified our method by obtaining the average workload of the M/M/1 system by means of the
system, where the batch size is geometric. In addition, the approximate blocking probabilities of the M/M/1 and
system with finite workload capacities are sought. The proposed method turns out to give a good approximation, which is compared with a simulation.