• 한국도서관정보학회지
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• 제41권1호
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• pp.5-28
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• 2010

이 연구의 목적은 차세대 도서관 목록의 주요한 기능적 특성을 살펴보는 것이다. 이를 위해 최근 OCLC의 WorldCat Local 기반으로 구축된 University of California 도서관의 '차세대 멜빌 파일로트'와 오픈소스 소프트웨어 Blacklight 기반으로 구축된 Stanford University 도서관의 'SearchWorks'의 사례를 분석하였다. 이들은 차세대 도서관 목록의 전형적 기능인 확장된 콘텐츠, 패싯 네비게이션, 키워드 검색, 검색결과의 적합성 순위화, 이용자 참여 기능을 모두 제공하지만, 그 범위와 내용은 다소 차이점을 보이며, 아직은 완성형이기보다 계속 수정 보완하며 발전해가는 과정에 있다고 할 수 있다.

• 전력전자학회논문지
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• 제6권1호
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• pp.43-48
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• 2001

기존의 풍력발전시스템은 풍속이 감소되면 블레이드가 저속으로 회전하기 때문에 보조발전의 도움이 없이는 자가 발전이 어려워서 한정된 풍속 조건에서만 작동이 가능하며, 풍속의 특성 때문에 풍력에너지의 이용효율이 대부 분 매우 낮다는 문제점이 있다 이와 같은 종래의 문제점을 해결하고 지역이나 지형에 크게 구애됨이 없이 풍속에 의해 발전이 이루어지다가 풍속의 저하로 출력된 전력이 적어지면 태엽에 저장된 회전에너지로 소형발전기를 운전 하여 축전지에 전력을 저장하여 부하에 전력을 연속적으로 공급하게 한다. 본 논문에서는 동력저장장치와 풍력발전기로 구성된 시스템을 설계 제작하여 풍력발전의 보상을 위한 동력저장 장치 시스템의 동작 특성을 분석하였다.

• 대한인간공학회지
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• 제31권4호
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• pp.557-565
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• 2012

Objective: This paper focuses on the new trend of applying NUI(natural user interface) such as gesture interaction into television and investigates on the design improvement needed in application. The intention is to find better design direction of NUI on television context, which will contribute to making new features and behavioral changes occurring in next-generation television more practically usable and meaningful use experience elements. Background: Traditional television is rapidly evolving into next-generation television thanks to the influence of "smartness" from mobile domain. A number of new features and behavioral changes occurred from such evolution are on their way to be characterized as the new experience elements of next-generation television. Method: A series of expert review by television UX professionals based on AHP (Analytic Hierarchy Process) was conducted to check on the "relative appropriateness" of applying gesture interaction to a number of selected television user experience scenarios. Conclusion: It is critical not to indiscriminately apply new interaction techniques like gesture into television. It may be effective in demonstrating new technology but generally results in poor user experience. It is imperative to conduct consistent validation of its practical appropriateness in real context. Application: The research will be helpful in applying gesture interaction in next-generation television to bring optimal user experience in.

• International Journal of CAD/CAM
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• 제4권1호
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• pp.47-53
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• 2004

The subdivision surface is the limit of recursively refined polyhedral mesh. It is quite intuitive that the multi-resolution feature can be utilized to simplify generation of NC (Numerical Control) tool paths for rough machining. In this paper, a new method of parallel NC tool path generation for subdivision surfaces is presented. The basic idea of the method includes two steps: first, extending G-Buffer to a strip buffer (called S-Buffer) by dividing the working area into strips to generate NC tool paths for objects of large size; second, generating NC tool paths by parallel implementation of S-Buffer based on MPI (Message Passing Interface). Moreover, the recursion depth of the surface can be estimated for a user-specified error tolerance, so we substitute the polyhedral mesh for the limit surface during rough machining. Furthermore, we exploit the locality of S-Buffer and develop a dynamic division and load-balanced strategy to effectively parallelize S-Buffer.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3365-3370
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• 2007

We developed micro power generation system using piezoelectric materials. In our system, the ambient vibrating energy is converting to electric energy by deflection of piezoelectric beams. The system consists of energy generating parts, converting enhancement parts, electric regulation and charging parts, and interface with small-energy-consuming mobile devices. The geometry of piezoelectric beams, the source of vibrating energy, and the electric load of target application determine the characteristics of generating electric power, such as impedance, voltage, current and power density. Therefore, we made a model for analysis of generating power with given information such as piezoelectric materials, geometry, vibration type, and mass. With this model, we can calculate capacitance of piezoelectric beams, generating voltage, current, and power. To obtain maximum energy transfer efficiency, we approached this study in the view of material, electrical, and mechanical engineering

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.127-131
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• 2005

The paper addresses modeling and analysis of a grid-connected photovoltaic generation system (PV system). PSCAD/EMIDC. an industry standard simulation tool for studying the transient behavior of electric power system and apparatus. is used to conduct all aspects of model implementation and to carry out extensive simulation study. An equivalent circuit model of a solar cell has been used for modeling solar array. A PWM voltage source inverter (VSI) and its current control scheme have been implemented. A maximum power point tracking (MPPT) technique is employed for drawing the maximum available energy from the PV array. Comprehensive simulation results are presented to examine PV array behaviors and PV system control performance in response to irradiation changes. In addition, dynamic responses of PV array and system to network fault conditions are simulated and analysed

• 전기학회논문지
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• 제59권1호
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• pp.16-18
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• 2010

This paper presents monitoring system based on IEC61400-25 for 750kW-class DFIG wind power generation system. It consists of wind turbine PLC, Local and Remote I/O Server, human machine interface, and Web-server. Proposed System has been demonstrated in Daegi-ri, Kangwon-do, which aims to test IEC61400-25 communication capability of monitoring system and evaluate the performance of 750kW-class WTS.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 추계학술대회 논문집
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• pp.63-66
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• 2001

This paper aims at developing remote control system to control and monitor distributed various devices such as photovoltaic Inverter system through internet. TCP/IP (Transmission Control Protocol/Internet Protocol) and photovoltaic inverter system operated in a row are adopted for network management protocol and applied device, respectively. For controlling and monitoring distributed devices in real-time, java-environment software is constructed. Also, HelloDevice, general-use interface controller between network device and applied device is proposed. Finally, serial communication such as RS-232C is used between controller and applied device.

• Journal of Power Electronics
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• 제14권2호
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• pp.324-340
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• 2014

Recent developments in power electronics technology have spurred interest in the use of renewable energy sources as distributed generation (DG) generators. The key component in DG generators is a grid-connected inverter that serves as an effective interface between the renewable energy source and the utility grid. The multifunctional inverter (MFI) is special type of grid-connected inverter that has elicited much attention in recent years. MFIs not only generate power for DGs but also provide increased functionality through improved power quality and voltage and reactive power support; thus, the capability of the auxiliary service for the utility grid is improved. This paper presents a comprehensive review of the various MFI system configurations for single-phase (two-wire) and three-phase (three- or four-wire) systems and control strategies for the compensation of different power quality problems. The advances in practical applications and recent research on MFIs are presented through a review of nearly 200 papers.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.494_495
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• 2009

This paper presents a study of DFIG wind power generation system for real-time simulation. For real-time simulation, the real-time digital simulator (RTDS) and its user friendly interface simulation software (RSCAD) are used. 2.2MW grid-connected variable speed DFIG wind power generation system is modeled and analyzed in this study. Stator-flux oriented vector control scheme is applied to stator, rotor side converter control, and back-to-back PWM converters are implemented for the decoupled control. The real-wind speed signal extracted by an anemometer is used for realistic and accurate simulation analysis. Block diagrams for DFIG and control scheme of stator, rotor-side are introduced. Real-time simulation cases are carried out and analyzed for the validity of this work.