• International Journal of Fuzzy Logic and Intelligent Systems
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• v.1 no.1
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• pp.6-12
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• 2001

Evolutionary algorithms(EAs) have been successfully applied to many combinatorial optimization problems of various engineering fields. Recently, some comparative studies of EAs with other stochastic search algorithms have, however, shown that they are similar to, or even are not comparable to other heuristic search. In this paper, a new hybrid evolutionary algorithm utilizing a new local heuristic search, for combinatorial optimization problems, is presented. The new intelligent local heuristic search is described, and the behavior of the hybrid search algorithm is investigated on two well-known problems: traveling salesman problems (TSPs), and quadratic assignment problems(QAPs). The results indicate that the proposed hybrid is able to produce solutions of high quality compared with some of evolutionary and simulated annealing.

• Journal of Korean Institute of Industrial Engineers
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• v.39 no.2
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• pp.119-128
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• 2013

Most internet users utilize internet portal search engines, such as Naver, Daum and Google nowadays. But since the results of internet portal search engines are based on universal criteria (e.g. search frequency by region or country), they do not consider personal interests. Namely, current search engines do not provide exact search results for homonym or polysemy because they try to serve universal users. In order to solve this problem, this research determines keyword importance and weight value for each individual search characteristics by collecting and analyzing customized keyword at external database. The customized keyword weight values are integrated with search engine results (e.g. PageRank), and the search ranks are rearranged. Using 50 web pages of Goolge search results for experiment and 6 web pages for customized keyword collection, the new customized search results are proved to be 90% match. Our personalization approach is not the way that users enter preference directly, but the way that system automatically collects and analyzes personal information and then reflects them for customized search results.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.95-98
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• 1996

Universal Learning Network(U.L.N.), which can model and control the large scale complicated systems naturally, consists of nonlinearly operated nodes and multi-branches that may have arbitrary time delays including zero or minus ones. Therefore, U.L.N. can be applied to many kinds of systems which are difficult to be expressed by ordinary first order difference equations with one sampling time delay. It has been already reported that learning algorithm of parameter variables in U.L.N. by forward and backward propagation is useful for modeling, managing and controlling of the large scale complicated systems such as industrial plants, economic, social and life phenomena. But, in the previous learning algorithm of U.L.N., time delays between the nodes were fixed, in other words, criterion function of U.L.N. was improved by adjusting only parameter variables. In this paper, a new learning algorithm is proposed, where not only parameter variables but also time delays between the nodes can be adjusted. Because time delays are integral numbers, adjustment of time delays can be carried out by a kind of random search procedure which executes intensified and diversified search in a single framework.

• Journal of the Korean Society for Library and Information Science
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• v.44 no.2
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• pp.241-262
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• 2010

This study aims to perform an evaluation of classification systems provided by major Korean search portals, Naver, Nate, Daum, and Yahoo-Korea. These classification systems are evaluated in terms of the consistency of classification system, logicality of classification system, ease of interface, clarity of category names, order of category and site listing, and hierarchical structure. The results of this study show that each search portal provides separate classification systems for their services. These results imply that it is crucial for search portals to implement a common classification system and a common interface for their services. This study could contribute to the development and improvement of portals' classification systems.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.2
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• pp.156-161
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• 1997

In this thesis, based on Genetic Algorithm, a new route search algorithm is presented to search an optimal route between the origin and the destination in intelligent route guidance systems in order to minimize the route traveling time. The proposed algorithm is effectively employed to complex road networks which have diverse turn constrains, time-delay constraints due to cross signals, and stochastic traffic volume. The algorithm is also shown to significantly promote search efficiency by changing the population size of path individuals that exist in each generation through the concept of age and lifetime to each path individual. A virtual road-traffic network with various turn constraints and traffic volume is simulated, where the suggested algorithm promptly produces not only an optimal route to minimize the route cost but also the estimated travel time for any pair of the origin and the destination, while effectively avoiding turn constraints and traffic jam.

• IE interfaces
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• v.17 no.spc
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• pp.97-102
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• 2004

AGV flowpath layout design is one of the most important steps for efficient AGV systems design. Since it was formulated by Gaskins & Tanchoco (1987), a unidirectional AGV flowpath layout design problem has been tackled by many researchers. However, the solution methods were traded off between the solution quality and the computational time. In this paper, a tabu search technique is applied to obtain a good solution for a relatively large problem in reasonable computational time. Specifically, fast construction algorithm for feasible initial solutions, long-term memory structure and neighbor solutions generation are adapted to the problem characteristics and embedded in the tabu search algorithm. Also, sets of computational experiments show that the proposed tabu search algorithm outperforms to the Ko and Egbelu's algorithm (2003).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.3
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• pp.684-691
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• 1996

Since the period of a spreading code in DS/SS communication systems is generally long, it is necessary to make the code acquisition as fast as possible. The code acquisition time can be sued as a measure to evaluate the performance of code acquisition systems. The search rate of serial search codee acquisition system used in the coventional CDMA cellular system is lower than that of the matched filter technique. In order to reduce the code acquisition time, this paper proposes hybrid code acquisition system composed filters combined with serial search blocks. In the proposed system, the matched filter sweeps possible code phases fast and the acquired phase information is verified by the serial search block. The mean and the variance of its acquisition time are calculated and compared with those of double dwell serial search system. The results indicate better performance of the proposed system by yielding its small vaues of the mean and the variance of code acquisition time.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.9
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• pp.1667-1673
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• 2009

This paper presents a application of new algorithm for feeder reconfiguration problem in distribution systems. Harmony Search (HS) algorithm, which is motivated from the musical performance, is used to reconfigure distribution systems so that active power losses are globally minimized with turning on/off the sectionalizing and the tie-line switches. In optimization processing, the HS algorithm has searching ability for the global optimal solution, simple coding of the iteration procedure, and fast convergence to get the solution. The HS algorithm is tested on 15 buses and 69 buses distribution systems, and the results prove its effectiveness to determine appropriate switching options without the occurrence of any misdetermination in switching and get the minimum power loss.

• Journal of the Korean Society for information Management
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• v.20 no.2
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• pp.27-41
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• 2003

Query logs are online records that capture user interactions with information retrieval systems and all the search processes. Query log analysis offers ad advantage of providing reasonable and unobtrusive means of collecting search information from a large number of users. In this paper, query logs of NAVER, a major Korean Internet search service, were analyzed to investigate the information seeking behabior of NAVER users. The query logs were collected over one week from various collecions such as comprehensive search, directory search and web ducument searc. It is expected that this study could contribute to the development and implementation of more effective web search systems and services.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2005.05a
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• pp.316-320
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• 2005

We developed Intelligent Product Search Agent based on SWRL, and this agent can search product information with knowledge(facts and rules) on the web, implement price comparison for searched products considering delivery rates. Existing keyword based product search engines is poor at searching intent products though a user has already prefect knowledge about intent produces. Furthermore if a user has insufficient knowledge, it is impossible to implement search. Also, existing price comparison shopping mall gives users comparison service considering total price(product prices, taxes, delivery rates), this service is valid to single product and has limitations of system expansion and up-dating because of not rule base but programming base. If there is appropriate knowledge on the Semantic web and this makes product information retrieval possible, above problems can be solved clearly. In this research, we developed Intelligent Product Search Agent based on SWRL that can search product information efficiently by making agent to handle facts and rules by itself.