• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.489-491
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• 1993

Many optimization problem or multiple attribute, multiple alternative decision making problem may have fuzzy evaluation factors. In this case, fuzzy number operation technique is needed to evaluate and compare object functions which become fuzzy sets. Generally, fuzzy number operations can be defined by extension principle of fuzzy set theory, but it is tedious to do fuzzy number operations by using extension principle when the membership functions are defined by complex functions. Many fast methods which approximate the membership functions such as triangle, trapezoidal, or L-R type functions are proposed. In this paper, a fast fuzzy number operation method is proposed which do not simplify the membership functions of fuzzy numbers.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.199-202
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• 2009

Scan design is currently the most widely used structured Design For Testability approach. In scan design, all storage elements are replaced with scan cells, which are then configured as one or more shift registers(also called scan chains) during the shift operation. As a result, all inputs to the combinational logic, including those driven by scan cells, can be controlled and all outputs from the combinational logic, including those driving scan cells, can be observed. The scan inserted design, called scan design, is operated in three modes: normal mode, shift mode, and capture mode. Circuit operations with associated clock cycles conducted in these three modes are referred to as normal operation, shift operation, and capture operation, respectively. In spite of these, scan design methodology has defects. They are power dissipation problem and test time during test application. We propose a new methodology about scan shift clock operation and present low power scan design and short test time.

• Journal of Korean Institute of Industrial Engineers
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• v.21 no.1
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• pp.85-101
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• 1995

Automated Guided Vehicles(AGVs) are widely used in computer integrated manufacturing(CIM) systems for material handling purposes. Although automated guided vehicles provide higher levels of flexibility and computer integrability, the installations are limited in number and one of the critical reasons lies in the complexity involved in the operation. The main objective of this research is to alleviate this problem by proposing efficient integrated operational control methods for AGV-based CIM systems. Particularly, this research is concerned with the mixed problem of dispatching automated guided vehicles and scheduling machines operation. The proposed dynamic heuristic algorithm uses various priority schemes and relevant information concerning the load of the system, the status of queues, and the position of AGVs in the scheduling process. The scheduling decision process is hierarchical in the sense that different decision criteria are applied sequentially to identify the most appropriate part to be served. This algorithm consists of two sections, the section of part selection by AGVs for the next service whenever an AGV completes the current assignment, and the section of part selection by machines for next service whenever a machine completes the current operation. The proposed algorithm has been compared with other scheduling schemes using the performance measure of mean flow-time and mean tardiness. Simulation results indicate that the proposed algorithm can reduce the mean flow-time and mean tardiness significantly.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1416-1418
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• 1999

This paper presents a restoration method by using Dijkstra algorithm for outage restoration problems in distribution system that considering load capacity constraints and operation constraints. Restoration problem in distribution system is difficult to solve problem in a short times, because of a distribution system that supplies power for customers combined with many tie-line switches and sectionalizing switches and have to satisfy plenty of operation conditions. Therefore, this paper applied Dijkstra algorithm which is satisfy radial operation conditions in distribution system. This proposed method used Kruskal algorithm include to Dijkstra algorithm Therefore, proposed method is restored to a outage sections in a short times and just then to satisfied with a operation conditions in distribution system. A 26-bus, 31-branch model system is used to demonstrate the effectiveness of the proposed method.

• The Journal of Korean Society for School & Community Health Education
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• v.17 no.1
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• pp.49-58
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• 2016

Objectives: This study was carried out to provide basic materials to draw up measures for courses operation and effective clinical practice operation for the cultivation of future effective problem solving ability by identifying the relationship between problem solving ability and clinical practice satisfaction of dental hygiene students. Methods: This study targeted 215 dental hygiene students from 3 universities located in Gyeonggi-do from November 30 to December 4, 2015. We analyzed the data with frequency analysis, descriptive statistics, t-test. One-way ANOVA, Pearson correlation coefficient, Regression analysis by using SPSS. Results: Clinical practice satisfaction between grades according to the general characteristics of the study subjects was analyzed and as a result, clinical practice satisfaction showed a significant difference depending on grade (t=-2.355, p=.019), major satisfaction(F=9.548, p=.000), health status(F=4.909, p=.008). The problem solving ability according to the general characteristics of the study subjects was compared and as a result, the problem solving ability score of students 'living apart from their family or living in lodgings' was found to be higher than that of students 'living with their family' (p=.023) and the problem solving ability of students who answered 'satisfied' with their major was higher than that of students who answered 'moderate' (p=.000). As the problem solving ability and major satisfaction are higher and health status is better, clinical practice satisfaction showed higher results (p<.01). Conclusions: The above results showed a correlation between the problem solving ability and clinical practice satisfaction of dental hygiene students and clinical practice satisfaction showed higher scores as the problem solving ability level was higher. Therefore, efforts to enhance dental hygiene students' clinical practice satisfaction are considered necessary by developing and providing a program to strengthen students' problem solving ability.

• Korean Management Science Review
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• v.26 no.1
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• pp.171-182
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• 2009

We consider the inventory replenishment problem and the vehicle routing problem simultaneously in the vending machine operation. This problem is known as the inventory routing problem. We design a memory cell in the clonal selection algorithm. The memory cell store the best solution of previous solved problem and use an initial solution for next problem. In general, the other clonal selection algorithm used memory cell for reserving the best solution in current problem. Experiments are performed for testing efficiency of the memory cell in demand uncertainty. Experiment result shows that the solution quality of our algorithm is similar to general clonal selection algorithm and the calculations time is reduced by 20% when the demand uncertainty is less than 30%.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.2
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• pp.191-200
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• 2004

DAF process has been designed considering raw water quality characteristics in Korea. Although direct filtration is usually operated, DAF is operated when the freshwater blooms occut or raw water turbidity become high. Pre-sedimentation iS prepared in case when raw water turbidity is very high by rainstorms. A main feature of this plant is that the operation mode can be changed (controlled) based on the characteristics of raw water to optimize the effluent quality and the operation costs. Treatment capacity (surface loading rate) and efficiency of DAF was found to be better than conventional sedimentation process. Moreover, low-density particles (algae and alum flocs) are easily separated while it is difficult to remove in sedimentation. One of the main concerns in adoption of DAF (Dissolved Air-Flotation) process is a high raw water turbidity problem. That is, DAF is not adequate for raw water, which is more turbid than 100NTU. In order to avoid this problem, pre-sedimentation basins are prepared in DAF plant to decrease the turbidity of DAF influent. For simulation of the actual operation, bench and full-scale tests were performed for highly turbid water conditions. Consequently, DAF process coupled with sedimentation is suggested that pre-sedimentation with optimum coagulation prior to DAF would be appropriate.

• Journal of Electrical Engineering and Technology
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• v.6 no.2
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• pp.284-292
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• 2011

This paper presents a load-shedding scheme using the Talmud rule in islanded microgrid operation based on a multiagent system. Load shedding is an intentional load reduction to meet a power balance between supply and demand when supply shortages occur. The Talmud rule originating from the Talmud literature has been used in bankruptcy problems of finance, economics, and communications. This paper approaches the load-shedding problem as a bankruptcy problem. A load-shedding scheme is mathematically expressed based on the Talmud rule. For experiment of this approach, a multiagent system is constructed to operate test islanded microgrids autonomously. The suggested load-shedding scheme is tested on the test islanded microgrids based on the multiagent system. Results of the tests are discussed.

• Journal of the Korean Operations Research and Management Science Society
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• v.19 no.1
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• pp.17-40
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• 1994

The objectives of this paper are to apply fuzzy cognitive map (FCM)- related techniques to (1) extract causal knowledge from a specific problem-domain and (2) perform a series of causal analysis in complicated decision making area. We propose a set operation-based augmentation (SOBA) algorithm to combine multiple FCMs developed by multiple experts. Based on the SOBA knowledge acquisition algorithm, we can obtain a causal knowledge base fairly representing multiple experts' knowledge about a problem domain. The causal knowledge base built by SOBA algorithm can be described as a matrix form, guaranteeing mathematically compact operation compared with a production (if-then) knowledge base. We applied out method to stock market analysis problem whichis a typical of highly unstructured problems in OR/MS fields.

• The Mathematical Education
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• v.49 no.3
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• pp.313-328
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• 2010

Mathematical modeling has been observed in the way of a possibility to contribute in improving students' problem solving abilities. One of the important views of real life problem context could be described such as a useful ways to interpret the real life leading to children's abstraction process. The problem contexts for the grade 6 with mathematical modeling perspectives were developed by reviewing the current 7th National Mathematics Curriculum of Korea. Those include the 5 content areas such as number & operation, geometry, measurement, probability & statistics, and pattern & problem solving. One of problem contexts, "Space", specially designed for pattern & problem solving area, was applied to the grade 6 students and analyzed in detail to understand student's mathematical modeling progress.