• Proceedings of the KSME Conference
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• 2000.04a
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• pp.894-899
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• 2000

An automatic mesh generation system with unstructured quadrilateral elements on trimmed NURBS surfaces has been developed.. In this paper, NURBS surface geometries in the IGES format have been used to represent model shape. NURBS surface is represented as parametric surface. So each surface could be mapped to a 2D parametric plane through the parametric domain. And then meshes with quadrilateral elements are constructed in this plane. Finally, the constructed meshes are mapped back to the original 3D surface through the parametric domain. In this paper, projection plane, quasi-expanded plane and parametric Plane are used as 2D mesh generation plane. For mapping 3D surface to parametric domain, Newton-Rhapson Method is employed. For unstructured mesh generation with quadrilateral elements on 2D plane, a domain decomposition algorithm using loop operators has been employed. Sample meshes are represented to demonstrate the effectiveness of the proposed algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.4
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• pp.774-781
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• 2004

The HF band SSB communication of coast radio station had operated with principal axis of maritime communication until early in the 1990. But, that is changed with development of data communication and satellite technique, which have operated a few by rapidly decrement of user with accomplishment of the CMDSS. Recently, the radio system of HF band is expanded to globe maritime communication, which is support to maritime safety information and data traffic service by low charge with the SSB high speed modem. This study have proposed the digitalize method for maritime communication system using HF band in domestic.

• The Transactions of the Korea Information Processing Society
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• v.7 no.3
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• pp.1025-1031
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• 2000

Pre-existing pattern recognition techniques, in the case of character recognition, have limited on the application field. But CAI character learning system and writer's recognition system are very important parts. The application field of pre-existing system can be expanded in the content that the learning of characters and the recognition of writers in the proposed paper. In order to achieve these goals, the development contents are the following: Firstly, pre-processing method by understanding the image structure is proposed, secondly, recognition of characters are accomplished b the histogram distribution characteristics. Finally, similarity measure functions are defined from standard character pattern for matching of the input character pattern. Also the effectiveness of this system is demonstrated by experimenting the standard primitive image.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.2
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• pp.137-142
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• 2010

A plane wave expansion method (PWEM) was applied for photonic band structure calculation. We examined zero group velocity modes in photonic crystal. The zero group velocity modes were obtained at the second band along F-K direction. We expanded higher order Brillouin zone (BZ) to find the locations of zero group velocity modes and to investicate their properties. We found twelve locations, inside the first Brillouin zone, where the group velocities became zero. Also, we calculated band structure and group velocity in off-plane configuration.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.116-122
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• 2004

The HF band communication of roast radio station had operated with principal axis of maritime communication until early in the 1990. But, that is changed with development of data communication and satellite technique, which have operated a few by rapidly decrement of user with accomplishment of the GMDSS. Recently, the radio system of 11u band is expanded to globe maritime communication, which is support to maritime safety information and data traffic service by low charge with the SSB high speed modem. This study have proposed the digitalize method for maritime communication system using HF band in domestic.

• The KIPS Transactions:PartD
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• v.12D no.5 s.101
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• pp.773-780
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• 2005

If XML queries are expanded based on ontology, broader search may be possible. On the other hand, queries that are not adequate to target documents may also degrade the search efficiency. We try to improve query adequacy by expanding query based on a reduced ontology, which is the result of ontology and target DTD match. The match considers ontology concepts and DTD elements as well as ontology and DTD attributes. Since the reduced ontology can improve the hit ratio of queries and also be successively reusable for XML documents of a kind, the proposed method can improve XML search efficiency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.410-410
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• 2007

광섬유 내에 첨가되어 있는 $GeO_2$ 등의 물질을 얼 확산시켜서 만드는 열확산 코어 광섬유는 열확산 기술에 따른 광섬유의 MFD(Mode Field Diameter)를 국소적으로 확대하여 굴절률 분포를 변화시킨 광섬유로 혹의 비틀림 및 간격에 대한 허용범위가 넓어지게 하여 접속 손실을 감소시킬 수 있다. 본 연구에서는 열확산 코어 광섬유를 제조할 때 안정된 얼확산 문제를 해결하기 위한 방법으로 트윈 토치를 이용한 프레임 브러싱 기법의 안정화된 코어 확장형 광섬유 제조시스템을 제작하였다. 또한 제작된 열확산 코어 광섬유 제조시스템을 이용하여 단일모드 조건을 만족하는 다양한 종류의 열확산 코어 광섬유가 제작됨을 확인할 수 있었다.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.6
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• pp.837-848
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• 2006

This paper presents the test results of biological aerated filtration(BAF) process to replace activated sludge process by enhancing treated effluent quality and reducing the costs. In BAF process both BOD and SS compounds in wastewater are degraded and removed by biological reaction and filtration. Upflow BAF with expanded polypropylene media and downflow BAF with ceramic media were used to investigate the effects of hydraulic and organic loads on effluent quality. As a result, in BAF processes which has different media, upflow BAF reactor shows 5% higher efficiency than downflow BAF and this phenomena caused by backwashing methods and operational conditions. The results of influence factors analyzed by Factor Analysis Method in BOD and SS treatment efficiency are the size of media, hight of media bed and type of media. The quantitative effects of media size are 5.73% in TBOD, 5.78% in SBOD and 7.65% in TSS, so we confirmed the main factor is media size.

• Journal of the Korea Society for Simulation
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• v.11 no.4
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• pp.91-105
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• 2002

The attackers on Internet-connected systems we are seeing today are more serious and technically complex than those in the past. So it is beyond the scope of amy one system to deal with the intrusions. That the multiple IDSes (Intrusion Detection System) coordinate by sharing attacker's information for the effective detection of the intrusion is the effective method for improving the intrusion detection performance. The system which uses BBA (BlackBoard Architecture) for the information sharing can be easily expanded by adding new agents and increasing the number of BB (BlackBoard) levels. Moreover the subdivided levels of blackboard enhance the sensitivity of the intrusion detection. For the simulation, security models are constructed based on the DEVS (Discrete EVent system Specification) formalism. The intrusion detection agent uses the ES (Expert System). The intrusion detection system detects the intrusions using the blackboard and the firewall responses these detection information.

• Journal of Magnetics
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• v.12 no.2
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• pp.68-71
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• 2007

Even a pure bulk Fe has a complicated magnetic phase and its magnetism is still needed to be clarified. In this study we investigated the magnetism of bcc and fcc bulk Fe with total energy calculations as functions of atomic volume. The full-potential linearized augmented plane wave method was adopted within a generalized gradient approximation. The ground state of bulk Fe is confirmed to be of ferromagnetic (FM) bcc. For fcc structured Fe an antiferromagnetic (AFM) state is more stable compared to FM states which exist as low spin and high spin states. The stable AFM states were found to accompany a tetragonal distortion, while the FM states remained in a cubic symmetry. At an expanded lattice constant a high spin FM state was calculated to be able to be stabilized with significant enhanced magnetic moment compared to the value of the ground state, bcc FM.