• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.126-129
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• 1997

This paper propose a new hybrid genetic algorithm for auto-tunig auzzy controller improving the performance. In general, fuzzy controller used pre-determine d moderate membership functions, fuzzy rules, and scaling factors, by trial and error. The presented algorithm estimates automatically the optimal values of membership functions, fuzzy rules, and scaling factors for fuzzy controller, using hybrid genetic algorithms. The object of the proposed algorithm is to promote search efficiency by overcoming a premature convergence of genetic algorithms. Hybrid genetic algorithm is based on genetic algorithm and modified gradient method. Simulation results verify the validity of the presented method.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.287-294
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• 2002

An automatic design method of steel frames using nonlinear analysis is developed. The geometric nonlinearity is considered by the use of stability functions. A direct search method is used as an automatic design technique. The unit value of each member is evaluated by using LRFD Interaction equation. The member with the largest unit value Is replaced one by one with an adjacent larger member selected in the database. The weight of the steel frame is taken as an objective function. Load-carrying capacities, deflections, interstory drifts, and ductility requirement are used as constraint functions. Case study of a three-dimensional two story frame are presented.

• The Journal of the Korea institute of electronic communication sciences
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• v.2 no.2
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• pp.136-141
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• 2007

To produce eco marine products which is taking interests recently, the necessity of aquafarm tracing system is being emphasized. Considering the particularity of aquafarm, wireless communication environment is essential in order to manage aquafarm efficiently. The terminal which automatically collecting the environmental information and transferring it to server needs specified functions; input-output the information conveniently and search it visually. In this paper, we design specified terminal and its functions to monitor the environmental information at aquafarm.

• IE interfaces
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• v.14 no.2
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• pp.190-197
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• 2001

Growth curves including Logistic and Gompertz functions are widely used in forecasting the market demand. To estimated the parameters of those functions, we use the non-linear least square method. However, it is difficult to set up the starting points for each parameter. If a wrong starting point is selected, the result reveals the local optimum or does not converge to a certain value. The purpose of this paper is to resolve the problem of selecting a starting point. Especially, rescaling the market data using the national economic index make it possible to figure out the range of parameters and to utilize the grid search method. Applications to some real data are also included.

• Journal of the Korean Institute of Intelligent Systems
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• v.12 no.3
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• pp.261-268
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• 2002

This paper represents that auto tunings of membership functions and weights in the fuzzy neural networks are effectively performed by immune algorithm. A number of hybrid methods in fuzzy-neural networks are considered in the context of tuning of learning method, a general view is provided that they are the special cases of either the membership functions or the gain modification in the neural networks by genetic algorithms. On the other hand, since the immune network system possesses a self organizing and distributed memory, it is thus adaptive to its external environment and allows a PDP (parallel distributed processing) network to complete patterns against the environmental situation. Also, it can provide optimal solution. Simulation results reveal that immune algorithms are effective approaches to search for optimal or near optimal fuzzy rules and weights.

• ETRI Journal
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• v.15 no.3
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• pp.47-59
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• 1994

A capacity expansion planning problem with buy-or-lease decisions is considered. Demands for capacity are deterministic and are given period-dependently at each period. Capacity additions occur by buying or leasing a capacity, and leased capacity at any period is reconverted to original source after a fixed length of periods, say, lease period. All cost functions (buying, leasing and idle costs) are assumed to be concave. And shortages of capacity and disposals are not considered. The properties of an optimal solution are characterized. This is then used in a tree search algorithm for the optimal solution and other two algorithms for a near-optimal solution are added. And these algorithms are illustrated with numerical examples.

• Korean Management Science Review
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• v.17 no.1
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• pp.65-86
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• 2000

Recently many organizations have attempted to build hypermedia systems to expand their working areas to internet-based virtual work places. It is thus important to manage corporate hypermedia documents effectively. Metadata play a critical role for managing these documents. This paper identifies metadata roles and components to build its schema. Furthermore a meta-information system HyDoMiS(Hyperdocument Meta-information System) is proposed by the use of this metadata schema. HyDoMiS performs three functions; metadata management search and reporting The metadata management function is concerned with workflow document and database. The system is more likely to help implement and maintsain hypermedia information system effectively.

• Journal of Korea Technology Innovation Society
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• v.6 no.3
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• pp.306-327
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• 2003

The importance of technology assessment(TA) is increasingly emphasized, however, the question of what is TA is ambiguous yet. This article traces the concept of TA, and tries to identify the its meaning and current issues. It argues that the ambiguity of TA concept is not tragedy, but blessing in its growth. We came to know that one should consider for a successful TA some issues : institutional conditions, methodology, functions and timeliness. And they should also be considered in the TA-building process of Korea which is now on.

• Proceedings of the Korean Society for Information Management Conference
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• 1998.08a
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• pp.15-18
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• 1998

본 연구의 목적은 4개의 인터넷 특허정보 데이터베이스의 탐색기능을 비교분석 함으로서 각 데이터베이스의 활용도를 제시하고 더 나아가 인터넷 상의 특허정보 데이터베이스의 이용자 우호적인 인터페이스 설계를 위한 기초 자료로 사용하려고 한다. 연구방법으로는 비교적 인지도가 높은 국내의 Patrom과 국외의 USPTO, QPAT-US, IBM을 선택하여 데이터베이스의 수록항목, 주요항목, 검색방법, 멀티미디어 검색기능, 웹으로 지원 가능한 정보자원의 형태를 중심으로 비교 분석한다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.04a
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• pp.133-136
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• 2004

This paper proposes a stability condition in affine Takagi-Sugeno (T-S) fuzzy systems with parametric uncertainties and then, introduces the design method of a fuzzy-model-based controller which guarantees the stability. The analysis is based on Lyapunov functions that are continuous and piecewise quadratic. The search for a piecewise quadratic Lyapunov function can be represented in terms of linear matrix inequalities (LMIs).