• Journal of Electrical Engineering and Technology
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• v.5 no.4
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• pp.511-521
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• 2010

This paper presents a new algorithm to determine accurate bus-wise transmission loss allocation utilizing path-integrals dictated by the transaction strategy. For any transaction strategy, the total sum of the allocated transmission losses of all buses is equal to the actual loss given by the AC power-flow calculation considering the distributed slack. In this paper, the bus-wise allocation of the transmission loss is calculated by integrating the differential loss along a path determined by the transaction strategy. The proposed algorithm is also compared with Galiana's method, which is the well-known transmission loss allocation algorithm based on integration. The performance of the proposed algorithm is evaluated by case studies carried out on the WSCC 9-bus, IEEE 14-bus, New England 39-bus, and IEEE 118-bus systems. The simulation results show that the proposed algorithm is fast and accurate with a large step size.

• Annual Conference of KIPS
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• 2000.10a
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• pp.829-832
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• 2000

스팸 전자우편과 전자우편 폭탄을 차단하기 위한 제품들은 많이 나와 있지만, 이러한 차단 제품들의 성능에 대한 신뢰성 있는 검증 자료는 많지 않으며. 검증 결과도 벤더(vendor)들의 주관이 개입될 수 있기 때문에 객관성과 공정성 면에서 부족하다고 하겠다. 이것은 차단 제품들의 성능과 잠재된 취약성을 분석하는 분석 방식의 부족과 기존의 분석 방식들의 한계성에 기인한다고 하겠다. 본 논문에서는 기존의 분석 방식들이 가지고 있는 한계점을 개선하고, 제품의 취약성 분석 과정을 자동화하여 소요되는 시간과 인력 낭비를 줄이고, 반복적으로 분석이 용이하며, 분석 결과와 관련된 취약성 정보를 제공하여 비전문가라도 취약성 분석이 용이한 SMTP 서버 보호를 위한 취약성 분석 자동화 도구를 제안한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06b
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• pp.23-28
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• 1996

Model-based coding is one of several approaches to very low bit rate image coding and it can be used in many applications such as image creation and virtual reality. However, its analysis and synthesis processes remain difficult, especially in the sense that the resulting synthesized image reveals some degradation in detailed facial components such as furrows around eyes and mouth. To solve the problem, a large number of methods have been proposed and the texture update method is one of them. In this paper, we investigate texture synthesis for model-based coding. In the update process of the proposed texture synthesis algorithm, texture information is stored in a memory and the decoder reuses it. With this method, the transmission bit rate for texture data can be reduced compared with the conventional method updating texture periodically.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.540-540
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• 2000

This paper explores design and control methods of a surgical robot for total hip replacement surgery which can be easily maneuvered by a surgeon Like an advanced surgical tool. The 3-DOF in-parallel surgical robot is fixed directly onto patient's femur by the bone clamp during surgery. With the master/slave combined surgical robot, the surgeon can directly control the motion of the surgical robot with surgeon's experience and judgment during operation. For the easiness of operation, the master/slave combined robot is controlled using admittance control paradigm. And for the precise operation, the robot motion is restricted at the surgical boundary using virtual hard wall display.

• The Journal of Korea Robotics Society
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• v.4 no.3
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• pp.218-224
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• 2009

We propose a formation-keeping and changing methods for outdoor multiple mobile robots in chained form. Our proposed method is designed to maintain the follower to its desired distance and orientation with respect to the pole using the concept of virtual force such as potential field. The client robots use a behavior-based control to perform kinematic control to keep formation under the centralized system in our software framework. The relationship of each poles that is expressed by set of distance and angle is the description of the formation type and the type converting is performed using this set. In addition, we also examine the stability and capability in the simulation and experiments with real robots.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.842-847
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• 2002

One of the challenging problems with bicycle simulators is to deal with the inherent unstable bicycle dynamics that is coupled with rider's motion. For the bicycle dynamics calculation and the real time simulation, it is necessary to identify the control inputs from the rider as well as the virtual environments. The six control forces of the Stewart platform-based motion system are used for estimation of the rider's action force, which is one of the important control inputs, but of which the direct measurement is impractical. For the effective estimation of the rider's action force, the dynamics model of the motion system is derived incorporated with both analytical and experimental methods and the sliding mode controller with perturbation estimation is developed.

• Transactions of Materials Processing
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• v.8 no.2
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• pp.127-134
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• 1999

This study suggests the practical method which can reduce the lead time of the field trial and design of the dies. The virtual manufacturing, with which the die design is evaluated by computer analysis, reveals the impropriety of a design before die makings. Three methods for reducing the die making process occupying over 60% of the automotive development are like follows: First, the crack and wrinkle occurrence can be prevented by virtually adjusting the blank holding force and drawbead force with a computer simulation. Second, the parts which can not remove the forming defects in spite of the adjustment of forming parameters need to modify the part geometry or punch temporary shape. Third, the simulation before field trial, and field trial simulation can be effectively used in die design.

• Journal of Korea Society of Digital Industry and Information Management
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• v.7 no.2
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• pp.19-27
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• 2011

Recent development of information technologies produces a lot of community services. Social Network Service is one of the community services on the world wide webs. In the Social Network Service, a user can register other users as friends and enjoy communication through a virtual message. Previous researches show a few social service methods using manually generated tagging. However, the manual social tagging is not widely used in many social network services. Moreover, they do not consider ubiquitous computing environment. We propose a recommendation method for social service using contexts in ubiquitous environment. Our method scores documents based on context tags and social network services. Our social scoring model is computed by both a tagging score of a document and a tagging score of a document that was tagged by a user's friends.

• Journal of Communications and Networks
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• v.14 no.6
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• pp.672-681
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• 2012

A potential breakthrough of the electrification of the vehicle fleet will incur a steep rise in the load on the electrical power grid. To avoid huge grid investments, coordinated charging of those vehicles is a must. In this paper, we assess algorithms to schedule charging of plug-in (hybrid) electric vehicles as to minimize the additional peak load they might cause. We first introduce two approaches, one based on a classical optimization approach using quadratic programming, and a second one, market based coordination, which is a multi-agent system that uses bidding on a virtual market to reach an equilibrium price that matches demand and supply. We benchmark these two methods against each other, as well as to a baseline scenario of uncontrolled charging. Our simulation results covering a residential area with 63 households show that controlled charging reduces peak load, load variability, and deviations from the nominal grid voltage.

• Ocean Systems Engineering
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• v.1 no.1
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• pp.1-15
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• 2011

Offshore structures are subjected to wind loads, wind generated wave excitations, and current forces. In this paper we focus on the wind generated wave excitations as the main source for the external forces on the structure. The main objective of the paper is to provide a tool for using deck acceleration measurements to predict the value of the force and moment acting on the offshore structure foundation. A change in these values can be used as an indicator of the health of the foundation. Two methods of analysis are used to determine the relationship between the force and moment acting on the foundation and deck acceleration. The first approach uses neural networks while the other uses a Fokker-Planck formulation. The Fokker-Plank approach was used to relate the variance of the excitation to the variance of the deck acceleration. The total virtual mass of the equivalent SDOF of the structure was also determined at different deck masses.