• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1241-1244
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• 2009

인터넷을 기반의 멀티미디어 정보화 사회에서, 대용량 멀티미디어 데이터 서비스에 대한 요구가 확산되고 있다. 그러나 현재의 가입자 접속망으로는 데이터 전송 속도 및 거리 제약으로 인해 만족스러운 서비스를 사용자들에게 제공해 줄 수 없다. 가입자 접속망에서 현저하게 떨어지는 속도문제를 해결하고, QoS(Quality of Service)를 보장해 줄 수 있는 방안의 하나로 우선순위 큐를 고려한 가중치 기반의 차등 대역폭 할당 방식과 대역폭을 분할하여 파장에 배정하는 파장 분할 방식의 EPON(Ethernet Passive Optical Network)을 제안한다. OPNET 으로 구현한 시뮬레이션 모델을 이용하여 고순위 및 저순위 트래픽의 비율에 따라 각 트래픽의 최대 및 평균 지연시간, 제안한 알고리즘의 사용율, 분배율을 구하여 적합성을 검증한다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.3
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• pp.281-284
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• 1983

Interrelationship between. certain physicochemical properties of milled rice was investigated. Grain hardness and milling time were correlated with grain dimension. Equilibrium moisture content of rice upon soaking at room temperature showed a high negative correlation with the amylose content. The contents of protein, fat and ash had no relationship with hardness, milling time and equilibrium moisture content.

• Journal of Korean Port Research
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• v.8 no.2
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• pp.1-35
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• 1994

The main arterial which runs through the in City of Pusan, carries about 60% of downtown traffic or more, maintains about 20% yearly increase in traffic is severely suffering from the traffic congestion because of concentrated traffic volumes regardless of peak-time periods. The purpose of this study was to grasp the traffic, geometric, and signal conditions of the main arterial through the Videologging System Techniques, perform the transportation system analyses, and finally suggest the improvements which could increase the travel capacity, reduce the average delay and fuel consumption with the optimal conditions of signal system. The following conclusions were drawn : firstly the traffic system should be shifted for the travel distribution on the arterial during the peak time periods, secondly the roadway system of the arterial reviewed for left-turn traffic during the peak time periods, and thirdly the signal system of intersection reconstructed for signal optimization or progression within the range of cycle length suggested.

• Journal of Korean Port Research
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• v.8 no.2
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• pp.67-77
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• 1994

A time-domain numerical model is developed to examine the performance of a wave energy focusing structure in combined waves and a current. With the current assumed to be slow and the structure fully submerged, the wave-current interaction problem is reduced to a wave scattering problem in a uniform current. The diffraction of incident waves around a narrow berm is considered. The shape of the berm is defined by a parabola, imitating that of an optical reflector. The energy focus is achieved by reflecting the incident waves through a predetermined focal point. Through the numerical simulations, the numerical model is shown to be effective in modeling the wave-current interaction problem, and the current speed and direction are shown to affect significantly the location, amplitude and sharpness of the focus.

• Journal of Korean Port Research
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• v.6 no.1
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• pp.37-48
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• 1992

This paper deals with the problem of port administration and management of the port of Pusan. As the port of Pusan has been administrated by central government, several problems on port administration and management have occurred. These include the time-lagged port development, the inconsistent port planning with city planning, the insufficient long-term port development planning the various operation authorities the low productivity of port and the lack of port sales activities etc. In addition to solving the above mentioned problems to diversify the function of port the following measures are to be taken for the port of Pusan ; the transfer from port administration system to port management system, the introduction of Port Authority with a board, and the conversion of the management system from production-oriented to marketing-oriented.

• Journal of Korean Port Research
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• v.5 no.2
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• pp.65-75
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• 1991

Tidal current and water level change in coastal waters are formulated in terms of mathematical models. A systematic discussion of the derivation of a set of governing equations, expressing conservation of mass and momentum is presented. A simplification is introduced by integrating all variables and equations over the total water depth, the Solution of the formulated problem is achieved by using the finite difference method(FDM). The applied study area is taken from Mokpo harbor and its adjacent coastal water which have significant hydrographical changes due to the construction of the estuary barrage and land reclamation work of estuary barren. Some comparisons with the observed current and water level changes the numerical solutions are found to be considerably fit well for the recent coastal water motion.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.713-716
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• 2011

인터넷 유저가 증가하면서 DDoS 공격은 인터넷 안정성에 매우 중요한 위협을 가하고 있다. 서비스 거부 공격이란 서비스를 제공하는데 있어 필요한 컴퓨팅 및 통신 자원을 고갈시키는 공격으로 원천적으로 해결하기가 매우 힘든 것으로 알려져 있다. 인터넷과 같은 대규모 망을 대상으로 한 네트워크 공격은 효과적인 탐지 방법이 요구된다. 그러므로 대규모 망에서 침입 탐지 시스템은 효율적인 실시간 탐지가 필요하다. 본 논문에서는 DDoS 공격에 따른 비정상적인 트래픽 범람을 방지하고 합법적인 트래픽 전송을 보장하기 위하여 엔트로피기반의 DDoS 공격 대응 기법을 제안한다. OPNET을 이용해 구현한 결과 DDoS 공격중에 원활한 서비스를 제공할 수 있는 것을 확인하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.467-468
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• 2011

본 논문에서는 촉각전달장치를 기반으로 수식에 대한 그래프와 도형과 같은 시각교육정보들을 촉각 정보로 자동 변환하여 제공하는 프로그램을 구현하였다. 구현한 프로그램으로는 입력된 그래픽 정보를 촉각정보전달 장치의 해상도에 적합하게 다운샘플링(downsampling)을 수행한 후, 이진화(binarization)를 통해 촉각신호를 생성한다. 그리고 이를 촉각정보전달 장치에 전달하여 출력함으로써, 시각장애인들에게 그래픽 정보를 촉각정보로 변환하여 제공할 수 있다. 결과적으로 본 프로그램을 통해 수학 및 과학과 같은 이공계열의 교육정보를 편리하고 빠르게 촉각정보로 변환하여 시각장애인들에게 제공할 수 있었다.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.1
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• pp.219-229
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• 1994

This paper describes an expert system on the cylindrical grinding operations in order to establish the optimum grinding conditions, which satisfy the maximum removal rates, considering the several constraints of grinding power, workpiece burn, chatter vibration and surface roughness. Specialized knowledge of the grinding operations are acquired from the actual operation database. Coefficientis in the experimental equations are obtaines through the fuzzy regression model based on the fuzzy set theory, and are stored in the actual operation database. The developed system is capable of determining the optimum grinding conditions taking into account some problems, and practical examples of implementaion are described.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.2
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• pp.190-196
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• 1993

Internal high speed grinding under several high grinding wheel speed condition has been performed in this study for the effects have analyzed and compared with the grinding power, grinding tangential force and accuracy of surface with the carbon tool steel(SK3). The following results have been obtained: (1) Under the workpiece speed constant condition, increasing the grinding speed, the tangential force is decreased, and on the contrary, accuracy of surface is improved. (2) Under the speed ratio (V$_{w}$/V$_{s}$) contant condition it is possible to increase the high machining efficiency constraint to tangential grinding force constant.ant.