• Proceedings of the KIEE Conference
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.55-56
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• 2015

A smart meter is a kind of electronic meters that measures and records consumption of electric energy in intervals of an hour or less and transmits that information to the remote places. AMI provides two-way communication path between utilities and consumers and should be able to support smart grid's new functionalities such as demand-response actions and real time pricing. The main objective of this paper is to provide a new diagnosis method and system for testing of smart meters in AMI neighborhood area network.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• 제24권1호
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• pp.103-109
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• 2015

This paper introduces a multi-purpose smart fusion sensor. Normally, this type of sensor can contribute to energy savings specifically related to lighting and heating/air conditioning systems by detecting individuals in an office building. If a fire occurs, the sensor can provide information regarding the presence and location of residents in the building to a management center. The system consists of four sensors: a thermopile sensor for detecting heat energy, an ultrasonic sensor for measuring the distance of objects from the sensor, a fire detection sensor, and a passive infrared sensor for detecting temperature change. The system has a wireless communication module to provide the management center with control information for lighting and heating/air conditioning systems. We have also demonstrated the usefulness of the proposed system by applying it to a real environment.

• Proceedings of the Korean Information Science Society Conference
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• 한국정보과학회 2006년도 한국컴퓨터종합학술대회 논문집 Vol.33 No.1 (A)
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• pp.307-309
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• 2006

요즘 들어 그리드 컴퓨팅 환경에서 실시간으로 지역적으로 분산된 기기, 실험 장비, 데이터 베이스, 인적 자원에 접근해야 되는 필요성이 강조되고 있다. 그러나 현실에서 제어되지 않는 분산환경에 실시간 모델을 구현하는 것과 실시간 시스템으로부터 외부시스템으로 통신하는 인터페이스를 정의하기 매우 힘들다. 아래 논문에서 그리드 환경 위에 쉽게 사용할 수 있는 TMO 기반의 실시간 제어를 할 수 있는 모델을 제안하고자 한다. 이 제안된 모델을 사용해서 이런 TMO 기반의 원경제어 시스템을 설계하고 개발함으로써 공학 기계 장비나 우주항공 실험 등 실제적인 장비에 사용하려고 한다.

• Transactions of the Korean Society of Machine Tool Engineers
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• 제14권5호
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• pp.55-61
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• 2005

In this paper, we propose the visual simulation system for virtual reality motion rider system. The visual simulation system can apply verity virtual reality system. This paper deals with programs on 3D automatic creation of terrain, road design, and a realtime rendering program for the virtual reality system. For the 3D automatic creation of terrain, DEM data and rectangular grid method are applied. We can make two different road object with the road design program. One of them includes road definition, and the other is obtained by using 'NURBS curve.' Visual simulation is consisted by additional modeling and real-time rendering. We can apply the programs made in this way to visual system of driving simulator.

• Journal of the Korean Society of Visualization
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• 제5권2호
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• pp.20-25
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• 2007

The geometry of a commercial passenger airplane is realized based on a Boeing 747-400 model through the photographic scanning and reverse engineering. The each element consisting of the plane such as fuselage, wing, vertical fin, stabilizer and engines, is individually generated and then the whole body is assembled by the photomodeler. The maximum error in the realized airplane is about 1.4% comparing with the real one. The three-dimensional inviscid steady compressible governing equations are solved in the unstructured tetrahedron grid system, and in a finite volume method using STAR-CD when the airplane flies at the cruise condition. The pressure distribution on the surface and the wing-tip vortices are visualized, and in addition to the aerodynamics coefficients, lift and drag are estimated.

• Journal of Internet Computing and Services
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• 제9권1호
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• pp.79-90
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• 2008

In the ubiquitous environment sensor network technologies have advanced for collecting information of the environment. With the rapid growth of sensor network technology, it is necessary and important to share the collected sensor data with a large base of diverse users. In order to provide dissemination of sensor data, we design an information dissemination system using an independent disseminator between provider and consumer. This paper describes how we designed the information dissemination system using one of the possible dissemination patterns for sensor networks, and an efficient matching algorithm called CGIM (Classed Grouping Index Matching) which employs a dynamic re-grouping scheme.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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• pp.719-724
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• 2007

Many engineering problems often require the large amount of computing resources for iterative simulations of problems treating many parameters and input files. In order to overcome the situation, this paper proposes an e-Science based computational system. The system exploits the Grid computing technology to establish an integrated web service environment which supports distributed high throughput computational simulations and remote executions. The proposed system provides an easy-to-use parametric study service where a computational service includes real time monitoring. To verify usability of the proposed system, two kinds of applications were introduced. The first application is an Aerospace Integrated Research System (e-AIRS). The e-AIRS adapts the proposed computational system to solve CFD problems. The second one is design and optimization of protein 3-dimensional structures.

• Journal of the Korean Solar Energy Society
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• 제26권1호
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• pp.91-98
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• 2006

Islanding phenomenon of utility-connected photovoltaic power conditioning systems(PV PCS) can cause a variety of problems and must be prevented. If the real and reactive power supplied by PV PCS are closely matched to those of load, islanding detection by passive methods becomes difficult. The active frequency drift(AFD) method, called the frequency bias method, enables islanding detection by forcing the frequency of the voltage in the islanding to drift up or down. In this paper, non-detection zone(NDZ) of AFD is analyzed for the islanding detection method of utility-connected PV PCS by the simulation software tool PSIM.

• Journal of Korean Society for Atmospheric Environment
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• 제9권E호
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• pp.347-357
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• 1993

The Lagrangian grid-free numerical method, the discrete vortex method, was applied to solve the Navier-Stokes euqations. This method avoids the introduction of numerical viscosity swamping the real physical viscosity at high Reynolds number, unlike Eulerian method, e.g. finite difference and element methods. The boundary integral equation method for the potential flow solution was included to make the discrete vortex method more feasible for complex geometries. The fast adaptive multipole expansion method was incorporated to reduce the computational time from $O(N^2)$ to O(N) for the computations of vortex-vortex interactions. The test problems were air flow around one circular cylinder and two circular cylinders in tandem with various gaps. The numerical results were in excellent gareement with the experimental and other computational results. The applicabilty of the method was discussed with the indoor and the outdoor air pollution problems, especially the contaminant transport in the recirculation regions.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제61권12호
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• pp.1944-1947
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• 2012

In this work, we investigated quench characteristics of matrix-type superconducting fault current limiters (MFCLs) according to the turn number of reactors. The reactors used in MFCLs apply magnetic field to superconducting elements within reactors when fault currents surge into MFCL systems. It makes the fast and simultaneous quenches between superconducting elements. Also reactors decrease the fault power burden of superconducting elements by bypassing the partial fault currents to itself, when quench occurs. These structure proposed in this work can be expected to achieve much more current limiting capacity even though it uses less superconductors compared with other type SFCLs. Three reactors were made by Bakelite. These reactors with the turn number of 190, 380 and 570, had the length of 270 mm and diameter of 80 mm. We reported experimental results, including fault currents, fault voltages and resistance in superconducting elements according to the turn number of reactors. We confirmed that experimental results will be useful in next future plan for the real power grid.