• 대한전기학회논문지:전력기술부문A
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• 제49권9호
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• pp.451-458
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• 2000

This paper addresses the issues of the parameter error detection and identification in electric power systems. In this paper, the parameter error identification and estimation is carried out as part of the state estimation. A two stage estimation procedure is used to detect and identify the parameter errors. The suspected parameters are identified by the WLAV state estimator as the first stage. A new WLAV state estimator adding the suspected system parameters in the state vector is used to estimate the exact value of parameter errors. Supporting examples are given by using IEEE 14 bus system.

• 한국정밀공학회지
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• 제20권10호
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• pp.218-225
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• 2003

A diagnostic system has been developed which reports modeling errors generated when exchanging CAD data using IGES (Initial Graphics Exchange Specification) format. The system determines whether the CAD data contains errors. It also helps to define the criteria for determining the integrity and interoperability of CAD data with downstream applications of another CAD/CAM/CAE/PDM systems. The methodology of our algorithms is to analyze IGES model data by identifying errors and anomalies with respect to the diagnosis of geometry and topology. The GUI (Graphic User Interface) of the developed system helps users to input values and to visualize diagnostic results at real time.

• 한국조경학회지
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• 제27권4호
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• pp.137-142
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• 1999

The purpose of this study is to develope a CAD-based tool for rasterization of polygonal vector map in AutoCAD. To identity the layer property of polygonal entity with user-defined coordinates as topology, algorithm in processing entity data of selection set that intersected with scan line was used, and the layers were extracted sequentially by sorted intersecting points in data-list. In addition to the functions for querying and modifying topology, two options for mapping were set up to construct plan projection type and to change meshes' properties in existing DTM data. In case of plan projection type, user-defined cell size of 3DFACE mesh is available for more detailed edge, and topological draping on landform can be executed in case of referring DTM data as an AutoCAD's drawing. The concept of algorithm was simple and clear, but some unexpectable errors were found in detecting intersected coordinates that were AutoCAD's error, not the utility's. Also, the routines to check these errors were included in algorithmic processing. Developed utility named MESHMAP was written in entity data control functions of AutoLISP language and dialog control language(DCL) for the purpose of user-oriented interactive usage. MESHMAP was proved to be more effective in data handling and time comparing with GRIDMAP module in LANDCADD which has similar function.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권4호
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• pp.511-519
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• 2016

This paper proposes a CMOS 6-bit phase shifter with low RMS phase and amplitude errors for an X-band phased array antenna. The phase shifter combines a switched-path topology for coarse phase states and a switch-filter topology for fine phase states. The coarse phase shifter is composed of phase shifting elements, single-pole double-throw (SPDT), and double-pole double-throw (DPDT) switches. The fine phase shifter uses a switched LC filter. The phase coverage is $354.35^{\circ}$ with an LSB of $5.625^{\circ}$. The RMS phase error is < $6^{\circ}$ and the RMS amplitude error is < 0.45 dB at 8-12 GHz. The measured insertion loss is < 15 dB, and the return losses for input and output are > 13 dB at 8-12 GHz. The input P1dB of the phase shifter achieves > 11 dBm at 8-12 GHz. The current consumption is zero with a 1.2-V supply voltage. The chip size is $1.46{\times}0.83mm^2$, including pads.

• 대한공간정보학회지
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• 제1권2호
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• pp.167-175
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• 1993

본 연구에서는 교통모형의 기술적인 단점을 보완하기 위하여 교통모형과 지리정보시스템을 결합하는데 있어서 교통모형의 입력자료를 지리정보시스템의 위상구조에서 추출하여 교통모형의 단점을 극복해 보는데 있다. 또한, 그래픽 기능을 이용하여 교통모형의 결과치를 화면상에서 직접 보여줌으로서 의사결정과정에 효율적으로 대처할 수 있을 것으로 보인다. 이 시스템은 특정도시나 지역에 쓰여질 수 있고, 하드웨어 발달에 따른 컴퓨터 사용시간 및 자료 입력시의 오류의 절감과 지리정보시스템의 교통에로의 응용을 가능케 할 것이며, 여행자 정보시스템(ATIS: Advanced Traveler Information Systems)에 활용할 수 있는 주행안내시스템(Route Guidence System) 또는 차량항법시스템(Vehicle Navigation System)의 기초적 자료 및 시스템 개발에 기여할 것이다.

• Structural Engineering and Mechanics
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• 제45권4호
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• pp.439-454
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• 2013

Hollow cylindrical tubes with a prismatic sandwich lining designed to replace the solid cross-sections are studied in this paper. The sections are divided by a number of revolving periodic unit cells and three topologies of unit cells (Square, Triangle and Kagome) are proposed. Some types of multiple-topology designed materials are also studied. The feasibility and accuracy of a homogenization method for obtaining the equivalent parameters are investigated. As the curved elements of a unit cell are represented by straight elements in the method and the ratios of the lengths of the curved elements to the lengths of the straight elements vary with the changing number of unit cells, some errors may be introduced. The frequencies of the first five modes and responses of the complete and equivalent models under an internal static pressure and an internal step pressure are compared for investigating the scope of applications of the method. The lower bounds and upper bounds of the number of Square, Triangular and Kagome cells in the sections are obtained. It is shown that treating the multiple-topology designed materials as a separate-layer structure is more accurate than treating the structure as a whole.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.343-347
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• 2008

Design of shape for visco-elastic vibration isolation elements, which are very cost-effective and so popular in many applications is frequently based on experiences, intuitions, or trial and errors. Such traditions in shape design make it difficult for drastic changes or new concepts to come out. In this paper, both topological method and shape optimization method are combined together to find out a most desirable isolator shape efficiently by using two commercial engineering programs. ABAQUS and MATLAB. The procedure is divided into two steps. At the first step, a topology optimization method is employed to find an initial shape. where density of either 0 or 1 for finite elements is used for physical realizability. At the second step, based on the initial shape, finer tuning of the shape is done by boundary movement method. An illustration of the procedure will be presented for a mount of an air-conditioner compressor system and the effectiveness will be discussed.

• 한국소음진동공학회논문집
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• 제18권12호
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• pp.1250-1255
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• 2008

Design of shape fur visco-elastic vibration isolation elements, which are very cost-effective and so popular in many applications is fi?equently based on experiences, intuitions, or trial and errors. Such traditions in shape design make it difficult for drastic changes or new concepts to come out. In this paper, both topological method and shape optimization method are combined together to find out a most desirable isolator shape efficiently by using two commercial engineering programs, ABAQUS and MATLAB. The procedure is divided into two steps. At the first step, a topology optimization method is employed to find an initial shape, where density of either 0 or 1 for finite elements is used fur physical realizability. At the second step, based on the initial shape, finer tuning of the shape is done by boundary movement method. An illustration of the procedure is presented fur a mount of an air-conditioner compressor system and the effectiveness is discussed.

• 한국자동차공학회논문집
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• 제10권3호
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• pp.151-158
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• 2002

Automotive engineers involved in a new car project use various CAD systems that are chosen based on work requirements. For example, engineers in Hyundai Motors are using Pro/Designer and Alias fur the style design, but they use CATIA to design parts and assemblies, ANSYS for FEM analysis, and Pro/Engineer to design engines. Because they use different CAD systems, they have difficulties in collaborative design. Data, which contains errors, is transferred between CAD systems. It is difficult to find out such errors in a large CAD model. An evaluation method for CAD models has been developed in this study. This diagnosis tool analyses a STEP or an IGES file generated from a CAD system, and produces a quantitative error report. The tool has been tested with actual data sets. This paper proposes an algorithm that produces mathematical error values of entities of IGES models that have geometrical data, and entities of STEP models that have topological data, and inspects every part off model. To develop this system, we have used the OpenCASCADE kernel, which is an open source kernel developed by Matra Datavision of France.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전력기술부문
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• pp.30-34
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• 2005

Due to old Toshiba EMS's database size limit and hardware old aging, KPX(Korea Power Exchange) had introduced New EMS from AREVA(old ALSTOM) in July 2002. After then KPX had committed many man power and time to normalize EMS NA(Network Analysis) functions for using real power system. At initial stage, to normalize State Estimator which is the backbone of all other NA functions and DTS(Dispatcher Training Simulator}, KPX had corrected numerous topology errors, network model errors, non-scanned and wrongly scanned SCADA measured errors. After SE function study, running test and tuning, State Estimator could finally have been run properly and stably from June 2003. Based on SE running, KPX had normalized real time Contingency Analysis, and study mode Power Flow, STNET and DTS. From early 2004, dispatchers have been trained to use NA and DTS for the purpose of stable SE running, NA operation & results reading and urgent equipment outage reviewing. EMS NA have been greatly contributed to operate real time power system stably. Above NA normal operation by KPX own efforts under the no experience of NA running, KPX made a good precedent. This paper is intended to introduce EMS NA normalization process, operation status, and etc in Korea power system operation.