• 대한전자공학회논문지SD
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• 제43권10호
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• pp.54-60
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• 2006

IEEE 1149.1 바운더리 스캔 칩들로 구성된 보드를 테스트하기 위한 패턴은 반드시 비트 스트림으로 구성되어야 한다. 그러나 이러한 비트 스트림을 생성하는 일은 IEEE 1149.1 표준에 대한 완벽한 지식이 필요하므로, 전문지식이 없는 SoC 설계자에게는 상당히 어려운 일이다. 본 논문에서는 Test Ready PCI 와 Test Ready USB로 정의한 PCI와 USB 장치를 통해 편리하게 테스트를 수행할 수 있게 도와주는 테스트 인터페이스 컨트롤러를 제안한다. 이 제어기는 TI사와 Lucent사에서 명령어 단위의 수준에서 테스트 비트 스트림을 생성하기위해 개발한 테스트 버스 컨트롤러를 기반으로 하여 테스트 전문 지식이 없는 설계자도 쉽게 테스트 패턴을 생성하여 테스트를 수행할 수 있는 장점이 있다.

• 대한산업공학회지
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• 제12권1호
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• pp.13-18
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• 1986

This paper is concerned with flow-shop permutation scheduling problem. This paper presents an algorithm for the minimum makespan sequence. The efficiency of proposed algorithm is demonstrated by comparisons with the existing algorithms: Johnson's, branch & bound method, and heuristic algorithms. The proposed algorithm is more effective than the other algorithms. A numerical example is given to illustrate the procedure.

• 산업경영시스템학회지
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• 제18권34호
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• pp.99-106
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• 1995

Recently, neural network is recognized as a new approach to solve jobshop scheduling problems in manufacturing system. Scheduling problem is known to be a difficult combinational explosive problem with domain-dependence variations in general. In addition, the needs to achieve a good performance in flexible manufacturing system increase the dimensions of decision complexity. Therefore, mathematical approach to solve realistic problems could be failed to find optimal or optimal-trending. In this paper a technique with neural network for jobs grouping by job-attributes and Gaussian machine network for generating to near-optimal sequence is presented.

• 산업융합연구
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• 제5권2호
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• pp.21-32
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• 2007

This paper deals with the sequencing problem in the operation of the manufacturing systems with the constraint of buffer capacity. Some of studies for this theme have been progressed for several years. And then most of them considered only one objective, such as maximum lateness, machine utilization, makespan, mean flowtime and so on. This study deal with two objectives of the delivery for customers and the idle time of machines for producers. For the decision of sequence, the utility function is used. The developed heuristic algorithm presents a good solution. Through a numerical example, the procedures of the job sequencing is explained.

• Progress in Superconductivity
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• 제4권1호
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• pp.42-47
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• 2002

Measuring magnetic fields with a SQUID sensor always requires preliminary adjustments such as optimum bas current determination and flux-locking point search. A conventional magnetoencephalography (MEG) system consists of several dozens of sensors and we should condition each sensor one by one for an experiment. This timeconsuming job is not only cumbersome but also impractical for the common use in hospital. We had developed a serial port communication protocol between SQUID sensor controllers and a personal computer in order to control the sensors. However, theserial-bus-based control is too slow for adjusting all the sensors with a sufficient accuracy in a reasonable time. In this work, we introduce programmatic control sequence that saves the number of the control pulse arrays. The sequence separates into two stages. The first stage is a function for searching flux-locking points of the sensors and the other stage is for determining the optimum bias current that operates a sensor in a minimum noise level Generally, the optimum bias current for a SQUID sensor depends on the manufactured structure, so that it will not easily change about. Therefore, we can reduce the time for the optimum bias current determination by using the saved values that have been measured once by the second stage sequence. Applying the first stage sequence to a practical use, it has taken about 2-3 minutes to perform the flux-locking for our 37-channel SQUID magnetometer system.

• 패션비즈니스
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• 제3권4호
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• pp.83-91
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• 1999

The purpose of this study is to provide some useful references to the educational field in terms of providing on analysis of job characteristics of fashion designers working in the women's wear industries. The data were collected from 102 fashion designers working in women's wear industries through the questionnaire and were analyzed by SPSS packages of frequencies and percentiles for comparative study, and the results are as follows: 1. The demographic characteristics of the fashion designers are; unmarried (80.4%), working less than 2 years (20.2%), completion of junior college(68.6%), majority ages between 20-24 yrs(43.1%). An average length of working in one company war less than 6 months. 2. The ratio computer usage of the design room was approx. 52.0% especially in the management of sales (52.9%) and the ratio in fashion design was approx. 17.6% in merchandising planning. 3. 76.4% of respondents was working 10 hours a day, and 50% of them was dissatisfied on the job caused by excessive working hour (31.4%) and job over load (35.3%). In the developing fashion design with the relation of actual job, insufficient knowledges of the concerned technical and production fields (68.6%) were indicated as the most difficult area. In addition, fashion magazines were considered as the most helpful resource(94.1%). 4. It was noted that the target age groups for the brand were clearly divided into two groups, notably the early and middle of twenties and the early and middle forties. Among the produced items, formal wears were accounted for 52.9%. 5. As far as the contents of job are concerned, the fashion designers are mostly engaged in purchasing textile, collecting informations of fashion, quality control, whereas their actual job is apparel design. 6. The training that the fashion designer received beside formal education includes attendance of private institutes(62.7%), OJT(7.8%), seminars(4.9%). Regarding formal education, the respond indicated that they had least opportunity to received computer training. 7. The necessary subjects in the schools for the fashion designers in relation to the current job were fashion information, merchandising planning, pattern making, cutting, fashion marketing, knowledges of clothing material in sequence. Subjects which are necessary for the further development include pattern making(21.6%), fashion marketing(14.7%), and designing with computer(7.8%).

• 대한조선학회논문집
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• 제60권3호
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• pp.202-211
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• 2023

The profile shops in shipyards produce section steels required for block production of ships. Due to the limitations of shipyard's production capacity, a considerable amount of work is already outsourced. In addition, the need to improve the productivity of the profile shops is growing because the production volume is expected to increase due to the recent boom in the shipbuilding industry. In this study, a scheduling optimization was conducted for a parallel welding line of the profile process, with the aim of minimizing tardiness and the number of set-up changes as objective functions to achieve productivity improvements. In particular, this study applied a dynamic scheduling method to determine the job sequence considering variability of processing time. A Markov decision process model was proposed for the job sequence problem, considering the trade-off relationship between two objective functions. Deep reinforcement learning was also used to learn the optimal scheduling policy. The developed algorithm was evaluated by comparing its performance with priority rules (SSPT, ATCS, MDD, COVERT rule) in test scenarios constructed by the sampling data. As a result, the proposed scheduling algorithms outperformed than the priority rules in terms of set-up ratio, tardiness, and makespan.

• 한국정보시스템학회지:정보시스템연구
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• 제25권4호
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• pp.105-119
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• 2016

Purpose 생산 일정계획 문제의 해법들은 일반적으로 총처리시간이 짧은 active 스케줄에 초점을 맞추어 해를 탐색하는 경우가 많다. 그러나 active 스케줄은 semi active 스케줄에 비해 생성하는 것이 까다롭기 때문에, 일정계획을 생성하는데 소요되는 계산 비용을 감안하면 semi active 스케줄을 적절히 활용하는 것이 도움이 될 수 있다. 이에, 본 논문에서는 동일한 생산 일정계획 문제에 active 스케줄기반 탐색 방법과 semi active 스케줄 기반 탐색 방법을 적용함으로써 이들의 성능을 비교해보고자 하였다. Design/methodology/approach 각 공정들의 작업장 할당 순서를 의미하는 permutation encoding 기반 유전 알고리즘을 고전적인 job shop 일정계획 문제에 적용하기 위해 본 논문에서는 active 스케줄 복호화 및 semi active 스케줄 복호화의 두 가지 복호화 방법을 소개하였으며, 이들은 공정들의 순열로부터 실행가능한 스케줄을 얻는데 사용되었다. Findings semi active 스케줄 기반 유전 알고리즘은 active 스케줄 기반 유전 알고리즘에 비해 최적해를 탐색하는데 소요되는 반복 횟수가 좀 더 많은 경향이 있었으나, 알고리즘 실행 시간을 훨씬 짧았다. 나아가, semi active 스케줄 복호화는 그 절차가 단순하여 이해하고 구현하기 용이하다는 장점이 있었다. 따라서, 효과적인 해 탐색 전략이 주어지는 경우에는 semi active 스케줄에 기반한 해법이 일정계획 문제 풀이에 도움이 될 수도 있을 것으로 보여진다.

• 한국경영과학회지
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• 제23권4호
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• pp.87-96
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• 1998

Using the concept of cellular manufacturing systems(CMS) in job shop manufacturing system is one of the most innovative approaches to improving plant productivity. However. several constraints in machine duplication cost, machining capability, cell space capacity, intercell moves and exceptional elements(EEs) are main problems that prevent achieving the goal of maintaining an ideal CMS environment. Minimizing intercell part traffics and EEs are the main objective of the cell formation problem because it is a critical point that improving production efficiency. Because the intercell moves could be changed according to the sequence of operation, it should be considered in assigning parts and machines to machine ceil. This paper presents a method that eliminates EEs under the constraints of machine duplication cost and ceil space capacity attaining two goals of minimizing machine duplications and minimizing intercell moves simultaneously. Developing an algorithm that calculates the machine duplications by cell-machine incidence matrix and part-machine Incidence matrix, and calculates the exact intercell moves considering the sequence of operation. Based on the number of machine duplications and exact intercell moves, the goal programming model which satisfying minimum machine duplications and minimum intercell moves is developed. A linear programming model is suggested that could calculates more effectively without damaging optimal solution. A numerical example is provided to illustrate these methods.

• 제어로봇시스템학회논문지
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• 제21권8호
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• pp.788-793
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• 2015

This paper proposes a path planning algorithm to reduce the inspection time of AOI (Automatic Optical Inspection) machines for SMT (Surface Mount Technology) in-line system. Since the field-of-view of the camera attached at the machine is much less than the entire inspection region of board, the inspection region should be clustered to many groups. The image acquisition time depends on the number of groups, and camera moving time depends on the sequence of visiting the groups. The acquired image is processed while the camera moves to the next position, but it may be delayed if the group includes many components to be inspected. The inspection delay has influence on the overall job time of the machine. In this paper, we newly considers the inspection delay time for path planning of the inspection machine. The unified approach using genetic algorithm is applied to generates the groups and visiting sequence simultaneously. The chromosome, crossover operator, and mutation operator is proposed to develop the genetic algorithm. The experimental results are presented to verify the usefulness of the proposed method.