• Journal of Power Electronics
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• 제12권5호
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• pp.787-799
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• 2012

Real and reactive power flows on a transmission line interact inherently. This situation degrades power flow controller performance when independent real and reactive power flow regulation is required. In this study, a quasi multi-pulse interline power flow controller (IPFC), consisting of eight six-pulse voltage source converters (VSC) switched at the fundamental frequency is proposed to control real and reactive power flows dynamically on a transmission line in response to a sequence of set-point changes formed by unit-step reference values. It is shown that the proposed hybrid fuzzy-PI commanded IPFC shows better decoupling performance than the parameter optimized PI controllers with analytically calculated feed-forward gains for decoupling. Comparative simulation studies are carried out on a 4-machine 4-bus test power system through a number of case studies. While only the fuzzy inference of the proposed control scheme has been modeled in MATLAB, the power system, converter power circuit, control and calculation blocks have been simulated in PSCAD/EMTDC by interfacing these two packages on-line.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.176-181
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• 2011

A role of cost modeler is that of facilitating design process by the systematic application of cost factors so as to maintain sensible and economic relationships between cost, quantity, utility and appearance. These relationships help to achieve the client's requirements within an agreed budget. The purpose of this study is to develop a parametric cost estimating model for the early design stage by using the multi-dimensional system of OLAP (On-line Analytical Processing) based on the case of quantity data related to architectural design features. The parametric cost estimating models have been adopted to support decision making in the early design stage. These models typically use a similar instance or a pattern of historical case. In order to effectively use this type of data model, it is required to set data classification and prediction methods. One of the methods is to find the similar class in line with attribute selection measure in the multi-dimensional data model. Therefore, this research is to analyze the relevance attribute influenced by architectural design features with the subject of case-based quantity data used for the parametric cost estimating model. The relevance attributes can be analyzed by Analytical Characterization. It helps determine what attributes to be included in the OLAP multi-dimension.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.68-73
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• 2011

This study was performed numerical analysis in order to analyze liquid film flow of heat exchanger tube arrangement and configuration of evaporative multi effect distillation system using medium-temperature. Simulation was accomplished the two-dimensional calculations using commercial analyses program FLUENT based on the FVM(finite volume method). Fresh water generator of this study used Shell & Tubes heat exchanger with Cu_Ni tube, configuration of tube used bare tube and corrugated tube, and arrangement of tube used in-line array and staggered array. Performance of heat exchanger through the formation of liquid film was compared and analyzed. Liquid film flow occurred that falling on heat exchanger tube wall. Result of simulation showed that liquid film thickness of in-line arrangement was found 0.57mm with bare tube and 0.67mm with corrugated tube, respectively. And liquid film thickness of staggered arrangement was found 0.39mm with bare tubes and 0.62mm with corrugated tubes, respectively. Liquid film thickness of corrugated tube showed thicker than bare tube, but heat transfer rates of corrugated tube showed higher than bare tube. The reason was considered that surface area of corrugated tube was wider than bare tube. And liquid film thickness of staggered arrangement showed thinner than in-line arrangement, so thermal performance of staggered arrangement showed higher than in-line arrangement.

• 정보처리학회논문지C
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• 제11C권5호
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• pp.645-652
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• 2004

본 논문에서는 대역폭과 지연 파라미터를 참조하여 PG내의 토폴로지 정보를 하는 기법으로 라인 세그먼트를 이용하여 경계노드 사이의 다중 경로 정보를 하였다. 제안된 star 토폴로지 기법에서는 모든 경로를 찾는 대신 홉 카운트 기반의 깊이 우선 방식을 사용하여 효율적으로 다중 경로를 탐색할 수 있도록 하였다. 이를 위해 토폴로지 정보를 줄이고 다중링크 에 유연성을 부여하기 위하여 대역폭과 지연의 한 쌍으로 구성된 두 개의 라인 세그먼트를 이용하는 수정된 라인 세그먼트 기법을 제안하였다. 그리고, 이를 기존의 star 토폴로지에 적용한 효율적인 토폴로지 기법을 제안하였다. 제안된 기법의 성능을 평가하기 위해 기존의 star 기법과 호 성공율, 접근시간 및 크랭크 백율에 대하여 컴퓨터 시뮬레이션을 통해 비교 분석하였다. 시뮬레이션 분석결과 제안된 star TA 기법이 기존의 기법보다 성능이 향상됨을 알 수 있었다.

• 지적과 국토정보
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• 제49권2호
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• pp.39-56
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• 2019

단선 일방통행 방식을 지하철 노선으로 도입한 사례는 국외에도 흔치 않은 사례이다. 국내에서는 서울 지하철 6호선의 응암순환선이 대표적인 단선 일방통행 방식의 구간이다. 본 연구는 이러한 응암순환선과 연립다세대 매매가격의 관계를 역과의 인접성 및 특징에 따른 효과를 규명하고자 하였다. 본 연구에서는 2006년부터 2017년까지의 총 17,938건의 연립다세대 매매가격의 자료를 활용하여 헤도닉가격모형을 이용한 분석을 진행하였다. 주요 분석의 결과는 다음과 같다. 첫째, 응암순환선특성으로 지하철역과의 인접성이 매매가격에 중요한 영향을 미친다는 것을 확인할 수 있었다. 거리구간별로는 100-200m 구간의 가격수준이 가장 높았고, 노선의 구조적 특징과 관련해서는 주요 지역으로의 이동성과 연결성이 우수한 불광역을 보행권으로 하는 연립다세대의 매매가격이 높게 나타났다. 둘째, 입지특성으로 버스정류장, 마트, 학교와 인접할수록 매매가격에 긍정적 효과를 미치는 것으로 분석되었다. 셋째, 연립다세대의 토지특성으로 토지면적은 작을수록 매매가격이 높았고, 토지의 세부적 특성인 형상과 방위, 도로접면에 따라서 매매가격에 미치는 유의적인 차이를 확인하였다. 넷째, 건물 및 소재층특성과 관련하여 주택유형과 건물규모, 경과연수, 승강기유무, 소재층에 따라 매매가격에 미치는 영향의 정도가 다른 것으로 분석되었다. 본 연구는 지하철역과의 인접성 및 특징에 따라 연립다세대의 가격에 미치는 효과가 상이하다는 것을 보여줌으로써 비아파트 수요변화에 대응한 주택가격 분석을 위한 참고자료로 활용되고자 한다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.795-802
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• 2001

The commutation and control in matrix converters is more complicated as in voltage source converters. Natural freewheeling paths do not exist and the theoretic absent storage elements result in a direct coupled system of load and line currents as well as voltages. The paper offers an overview about staggered commutation and control policies in matrix converters. Based on the knowledge about load current direction and the signs of the line to line input voltages different multi-step commutation policies were derived. This paper examines the application of that policies in the case of space vector modulation and direct control methods with the focus on the resulting effects to the reference output voltage deviation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.310-313
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• 1996

In this paper, a neural control algorithm is proposed on the automation of adjustment process. The adjustment processes in camcoder production line are modelled, and the processes are adjusted automatically by means of off-line supervisory trained multi-layer neural network. We have made many experiments on the several adjustment processes by using the control algorithm. There are many unexpected troubles to achieve the desirable adjust time in the practical application. To overcome those, some auxiliary algorithms are demanded. As a result, our proposed algorithm has some advantages - simple architecture, easy extraction of the training data without expertises, adaptability to the varying systems, and wide application for the other resemble processes.

• Journal of applied mathematics & informatics
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• 제33권1_2호
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• pp.77-87
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• 2015

Parallel lines are often used to increase production rate in many manufacturing systems where the main line splits into several lines in parallel, and after some operations, they merge into a main line again. Queueing networks with finite buffers have been widely used for modeling and analyzing manufacturing systems. This paper provides an approximation technique for multi-server two-stage networks with merge configuration and blocking which will be a building block for analysis of general manufacturing systems with parallel lines and merge configuration. The main idea of the method is to decompose the original system into subsystems that have two service stations with multiple servers, two buffers and external arrivals to the second stage are allowed. The subsystems are modeled by level dependent quasi-birth-and-death (LDQBD) process.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1081-1085
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• 2015

In this paper a printed pair dipole antenna with double tapered microstrip balun for wireless communications is proposed. The proposed antenna consists of a pair arm of different sizes that is branched microstrip line and microstrip line with the ground plane on opposite side of the dielectric substrate plane. The proposed antenna is matched between the ground plane to the microstrip line by double tapered microstrip balun. This antenna obtains multi-band radiation frequency band. The impedance bandwidths for a reflection coefficient of VSWR ≤ 2 are about 1.01 GHz (2.35~3.336 GHz), 1.56 GHz (4.7~6.26 GHz) and 1.15GHz (6.85~8.0[GHz]). Additionally, the measurement peak gain is about 3.6 dBi. The proposed antenna is able to support wireless communication applications.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2016년도 추계학술발표대회
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• pp.681-682
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• 2016

In this study we propose a novel approach to segment a terrain in two parts: ground and none-ground. The terrain is gained by a multi-channel 3D laser range sensor. We process each vertical line in each frame data. The vertical line is bounded by the sensor's position and a point in the largest circle of the frame. We consider each pair of two consecutive points in each line to find begin-ground and end-ground points. All points placed between a begin-ground point and an end-ground point are ground ones. The other points are none-ground. After examining all vertical lines in the frame, we obtain the terrain segmentation result.