• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.3
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• pp.241-247
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• 2011

Marine casualties of vessel are said to be in most case caused by human error, but it would be valid for the assumption that the ship is built with high quality and then should be acceptable to the safety standards. It means that the inherent characteristics of a ship should be the first consideration on the safety of ship. Therefore it is basically necessary for navigator to grasp the inherent stability of his ship and ensure that the ship complies with the minimum statutory standards of stability. This study is to realize the stability of the Korean offshore large purseiner varying with loading conditions by the inclining data and some calculations. The author compared the stability of the ship with IMO criteria and domestic rule, and proposed some improvement for the safety of the ship. The results are summarized as follows ; The values of GM of the ship according to the loading condition in navigation satisfy both of the IMO criteria and the domestic rule, but in case of the area under the GZ curves between the heel angles of $30^{\circ}$ and $40^{\circ}$, and the heel angle occuring the maximum righting lever not satisfy the IMO rule at the fishing ground departure and arrival conditions in the haul in net situation. The initial metacentric height of the ship is very large, but the range of stability and the occurring angle of the maximum GZ are very small, so even small inclining can bring about the beam end. The best method of improvement for that is to increase the freeboard of the model among the variables.

• The KIPS Transactions:PartB
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• v.9B no.6
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• pp.783-790
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• 2002

This paper proposes a fuzzy Pr/T net representation of interval-valued fuzzy set reasoning, where fuzzy production rules are used for knowledge representation, and the belief of fuzzy production rules are represented by interval-valued fuzzy sets. The presented interval-valued fuzzy reasoning algorithm is much closer to human intuition and reasoning than other methods because this algorithm uses the proper belief evaluation functions according to fuzzy concepts in fuzzy production rules.

• Journal of Mechanical Science and Technology
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• v.14 no.6
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• pp.655-665
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• 2000

We propose an efficient algorithm for the purpose of satisfying a wide range of design constraints represented with equality and inequality equations as well as production rules. The algorithm employs simulated-annealing and a production rule inference engine and works on design constraints represented with networks. The algorithm fulfills equality constraints through constraint satisfaction processes like variable elimination while taking into account inequality constraints and inferring production rules. It can also reduce the load of the optimization procedure if necessary. We demonstrate the implementation of the algorithm with the result on machine tool design.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.280-287
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• 2001

There have been some studies about hybrid production system, which integrate push system and pull system. Most of them are based on the simple production system considering one product line. Though there are many studies about hybrid production system, it\`s not practical to implement them for real factory, because most of them did not consider various factors about real factory. On this study we designed hybrid production system considering some factor - one is automatic kanban generation, the other is dispatching rule for Multi-tasking worker, and the last one is the priority of kanban. At last, We give simulation results fur a real company, which produce various cameras in Korea.

• Speech Sciences
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• v.13 no.2
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• pp.107-120
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• 2006

The main purpose of this study is to investigate whether Korean learners can use the vowel duration cue to distinguish voicing contrasts in word-final consonants in English. Given that the Korean group's performance on the auditory task was much better than their performance on the identification task or on the production task, we conclude that the AX discrimination task makes contact with a different layer of perception. In particular, the AX discrimination task can be done at the auditory or phonetic level, where differences in vowel length are still encoded in the representation. In contrast, the identification and production tasks are probing the mental representation of vowel length and voicing. It was also founded that Korean speakers stored neither vowel length nor voicing in memorized representations and did not internalize the lengthening of the preceding vowel as a rule to differentiate the voicing contrasts of final consonants, even though they were able to detect the acoustic differences in vowel duration provided that they were tested in an appropriate task.

• Transactions of Materials Processing
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• v.8 no.6
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• pp.591-603
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• 1999

A computer-aided process planning system for rotationally symmetric deep drawing products has been developed. The application for non-axisymmetric components, however, has been reported yet. Therefore, this study investigates process sequence design in deep drawing process and constructs a computer-aided process planning system for non-axisymmetric motor frame products with elliptical shape. The system developed consists of three modules. The first one os a 3-dimensional modeling module to calculate surface area for non-axisymmetric products. The second one is a blank design module that creates an oval-shaped blank with the identical surface area. The third one is a process planning module based on production rules that play the best important roles in an expert system for manufacturing. The production rules are generated and upgraded by interviewing with field engineers. Especially, drawing coefficient, punch and die radii are considered as main design parameters. The constructed system for elliptical deep drawing products would be very useful to reduce lead time and improve accuracy for production.

• IE interfaces
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• v.22 no.2
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• pp.144-152
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• 2009

Assembly line has been recognized as an efficient production system in mass production. However, the recent production environment characterized as mass customization urges production managers to transform a long assembly line to a number of short assembly cells. To maximize the utilization of resources in an assembly cell, it is important to have the line balanced. This paper presents a bucket brigade-based assembly cell. Bucket brigade is a way of coordinating workers who progressively perform a set of assembly operations on a flow line. Each worker follows a simple rule: perform assembly operations on a product until the next worker downstream takes it over; then go back to the previous worker upstream to take over a new assembly job. In this way, the line balances itself. The bucket brigade assembly cell is analyzed and compared with traditional assembly lines and general assembly cells. The paper also discusses some prerequisite requirements and limitations when the bucket brigade assembly cells are employed.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.27 no.3
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• pp.37-44
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• 2004

국내 반도체 산업은 불과 20년도 안 되는 짧은 기간동안에 괄목할만한 성장을 하여 전세계 반도체 생산 규모 면에서 3위 국가로 부상하였으며, 기술 경쟁력 면에서도 한국인의 자존심을 그나마 지켜왔다. 하지만, 반도체 제조는 가장 복잡한 제조공정의 하나로 분류되며, 이러한 복잡한 시스템을 통제하기 위해서는, 다양한 시스템 조건 하에서 적절한 생산전략을 마련하는 것이 필요하다. 그러나, 반도체 제조 시스템에 대한 다양한 상황과 관련한 연구는 많지 않다. 반도체 제조공정 시스템에 대한 스케줄은 생산공정의 재진입, 공정의 높은 불확실성, 급속하게 변하는 제품과 기술과 같은 특성 때문에 반도체 제조공정 시스템에 대한 스케줄은 복잡하고 어려운 작업이며, 사이클타임의 절감 및 단위시간당 생산량의 증대와 같은 시스템 목적을 달성하기 위하여, 반도체 제조 시스템에 대한 좋은 방법을 발견하기 위한 많은 연구가 있었다. 반도체 산업의 생산 흐름은 가장 독특한 특징을 가지고 있으며 생산계획과 반도체 제조의 스케줄링과 계획을 어렵게 하고 있다. 현재 반도체 조립공정에서 수행되고 있는 일정계획은 단순 FCFS (First Come First Serve)에 의한 할당규칙에 따른다. 또한 Backlog(예비재고)를 1일 생산량을 기준으로 Buffer로 운영하고 있다. 따라서 본 연구에서는 효율적인 재고관리와 정확한 스케줄링이 생산의 경쟁력 확보 우위임을 가정하여 다양한 할당규칙(dispatching rule)을 실시간 적용하여 정확한 일정계획 수립의 효과와 결과를 시뮬레이션을 통해 검증하고자 한다. 제시된 방법론을 위하여 시뮬레이션 접근방법이 사용되었다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.5
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• pp.94-102
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• 2003

This paper presents active management of feeder automation systems using active database. DAS(Distribution Automation System) has been managed for feeder automation in passive manner. Therefore, feeder automation system has to be managed by operator when feeder overloadings is detected. It may be possible for propagating the feeder overloadings area by operator's mistake. To overcome this defect, the author proposed the feeder automation technique with active manner to obtain feasible feeder reconfiguration. Active database can manage feeder automation system by data driven monitoring of events and by corresponding actions without operator's intervening. To manage feeder automation system with active manner, production rule, active rule manager are designed. And active database system architecture for feeder automation system is proposed. Test results on the KEPCO's 108 bus distribution system show that the performance is efficient and robust.

• International Journal of Control, Automation, and Systems
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• v.4 no.3
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• pp.372-381
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• 2006

The purpose of this study was to develop a process management system to manage ingot fabrication and improve ingot quality. The ingot is the first manufactured material of wafers. Trace parameters were collected on-line but measurement parameters were measured by sampling inspection. The quality parameters were applied to evaluate the quality. Therefore, preprocessing was necessary to extract useful information from the quality data. First, statistical methods were used for data generation. Then, modeling was performed, using the generated data, to improve the performance of the models. The function of the models is to predict the quality corresponding to control parameters. Secondly, rule extraction was performed to find the relation between the production quality and control conditions. The extracted rules can give important information concerning how to handle the process correctly. The dynamic polynomial neural network (DPNN) and decision tree were applied for data modeling and rule extraction, respectively, from the ingot fabrication data.