• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1991년도 춘계공동학술대회 발표논문 및 초록집; 전북대학교, 전주; 26-27 Apr. 1991
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• pp.464-464
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• 1991

We address the problem of designing a physical CATV network with switched-star topology in which the broadband interactive service is provided. There are two types of decision variables: One is where to place conduit paths, and the other is how many cable units to be installed on each link traversed by an established conduit path. Due to the serious drawback of the conventional approach partitioning the problem into two subproblems, the unified approach handled in one setting is used here to attack the whole problem without dividing into two ones. In this paper, we present a mathematical design model and propose an efficient solution method exploiting the nice structure of it. In addition to this physical design, some results on logical network configuration have also been made. Finally, computaional experiments are conducted to illustrate the efficiency of our design approach.

• Journal of Power Electronics
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• 제16권1호
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• pp.133-141
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• 2016

This paper focuses on the development of a Five-Level Flying-Capacitor Dual Buck Inverter (FLFCDBI) based on the main circuit of dual buck inverters. This topology has been described as not having any shoot-through problems, no body-diode reverse recovery problems and the half-cycle work mode found in the traditional Multi-Level Flying-Capacitor Inverter (MLFCI). It has been shown that the flying-capacitor voltages of this inverter can be regulated by the redundant state selection within one pole. The voltage balance of the flying-capacitors can be achieved by charging or discharging in the positive (negative) half cycles by choosing the proper logical algorithms. This system has a simple structure but demonstrates improved performance and reliability. The validity of this inverter is conformed through computer-aided simulation and experimental investigations.

• 전기학회논문지
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• 제66권1호
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• pp.137-143
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• 2017

In this paper, we investigate static control of Boolean networks described in the framework of semi-tensor product (STP) operation. The control objective is to determine control input nodes and their logical values so as to stabilize the considered Boolean network to a desired fixed point or cycle. Using topology of Boolean networks such as incidence matrix and hub nodes, a set of appropriate control input nodes is selected, and based on STP operations, we assign constant control inputs so that the controlled network can converge to a prescribed fixed point or cycle. To validate applicability of the proposed scheme, we conduct a numerical study on the problem of determining control input nodes for a Boolean network representing hierarchical differentiation of myeloid progenitors.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권1호
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• pp.52-68
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• 2019

Aiming at the optimal placement of communication relay nodes (OPCRN) problem in manned/unmanned aerial vehicle cooperative engagement system, this paper designed a kind of fully connected broadband backbone communication topology. Firstly, problem description of OPCRN was given. Secondly, based on problem analysis, the element attributes and decision variables were defined, and a bi-level programming model including physical layer and logical layer was established. Thirdly, a hierarchical artificial bee colony (HABC) algorithm was adopted to solve the model. Finally, multiple sets of simulation experiments were carried out to prove the effectiveness and superiority of the algorithm.

• 한국패션뷰티학회지
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• 제4권1호
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• pp.28-34
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• 2006

The purpose of this study is to historically examine the thoughts and ideas of geometry and to analyze the expression style of design applied to the mass communication such as magazines and world wide webs, by giving definitions on the ideas of geometry and the pattern of cognition. Geometry was evolved to Descartes's analytical geometry, projective geometry, non-Euclidean geometry and Topology at the end of 19th century. When geometry applies to design styles, it is devided into two field, plane geometry and solid geometry. The development of geometry was completed from the Pythagoras symbolic theory of number to Platonic spiritual geometry and Euclidean geometry. It can be studied that those have what kind of symbolic meanings and transformations on each hair design plan. It can also analized how those symbolic forms are appeared on the design form. This tendency means that there is always a try for the use of geometry as reasonable device for hair design. If the hair design and geometry have logical and artistical relation, we can make buildings which have a order, balance and harmony.

• Spatial Information Research
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• 제8권1호
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• pp.31-50
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• 2000

국가 GIS 구축사업의 일환으로 지형도를 비롯한 여러 가지 주제들이 수치지도로 구축되어왔다. 이렇게 구축된 수치지도는 사용하고자 하는 목적에 맞게 올바르게 구축되어 그 정확도를 신뢰할 수 있을 경우에만 효율적으로 사용될 수 있다. 본 연구의 목적은 양질의 수치지도를 구축하는데 필요한 합리적인 검수방안을 제시하는데 있다. 이를 위해 국내·외에서 요구되는 수치지도의 품질요소와 검수현황을 살펴보았고, 수치지도에서 발생하는 오류유형을 분석했다. 이러한 오류유형을 바탕으로 데이터생성연혁, 데이트포맷, 위치정확성, 속성정확성, 기하구조의 적합성, 논리적 일관성, 경계인접, 완전성, 도곽선 범위의 9가지 기존을 마련한 뒤 작업계획, 오류유형 정의, 납품내역검수, 육안중첩검수, 현지조사검수, 전산정밀검수, 자동검수, 검수결과판정, 검수결과해석으로 이어지는 9단계의 체계적인 다단계 검수절차를 제안하였다.

• 한국인터넷방송통신학회논문지
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• 제12권5호
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• pp.197-203
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• 2012

본 논문에서는 광파장다중화(WDM) 기반 광인터넷 환경에서 논리적인 다중 링 구조에 의한 통신망 복구 기법의 대역폭 효율성을 연구한다. 이 방법은 링 토폴로지의 특성을 이용해 빠르고 간단한 복구 동작을 제공하며, 지역적인 복구를 수행한다. 동시에 다중 링 구성을 통하여 대체 경로의 분산과 공유 정도를 높이고 단위 링크당 예약되어야 하는 예비 광파장의 수를 줄임으로써 전체 통신망 자원 이용의 효율성을 높일 수 있다. 본 논문에서는 위험공유링크그룹(SRLG) 개념을 이용하여 링크 손실을 복구하는데 필요한 예비대역폭 비율을 토폴로지상의 Cut-Set을 이용해 계산하고 이를 실험을 통해 비교 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권4호
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• pp.1630-1642
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• 2016

Inter-domain routing is the most critical function of the Internet. The routing system is a logical network relying on the physical infrastructure with geographical characteristics. Nature disasters or disruptive accidents such as earthquakes, cable cuts and power outages could cause regional failures which fail down geographically co-located network nodes and links, therefore, affect the resilience of inter-domain routing system. This paper presents a model for regional failures in inter-domain routing system called REFER for the first time. Based on REFER, the resilience of the inter-domain routing system could be evaluated on a finer level of the Internet, considering different routing policies of intra-domain and inter-domain routing systems. Under this model, we perform simulations on an empirical topology of the Internet with geographical characteristics to simulate a regional failure locating at a city with important IXP (Internet eXchange Point). Results indicate that the Internet is robust under a city-level regional failure. The reachability is almost the same after the failure, and the reroutings occur at the edge of the Internet, hardly affecting the core of inter-domain routing system.

• Journal of Power Electronics
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• 제14권3호
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• pp.507-518
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• 2014

This paper presents a new cascaded asymmetrical single phase multilevel converter with a lower number of power semiconductor switches and isolated DC sources. Therefore, the number of power electronic devices, converter losses, size, and cost are reduced. The proposed multilevel converter topology consists of two H-bridges connected in cascaded configuration. One H-bridge operates at a high frequency (high frequency inverter) and is capable of developing a two level output while the other H-bridge operates at the fundamental frequency (low frequency inverter) and is capable of developing a multilevel output. The addition of each power electronic switch to the low frequency inverter increases the number of levels by four. This paper also introduces a hybrid switching algorithm which uses very simple arithmetic and logical operations. The simplified hybrid switching algorithm is generalized for any number of levels. The proposed simplified switching algorithm is developed using a TMS320F2812 DSP board. The operation and performance of the proposed multilevel converter are verified by simulations using MATLAB/SIMULINK and experimental results.

• 전자공학회논문지CI
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• 제45권3호
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• pp.1-6
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• 2008

데이터 그리드는 지리적으로 분산된 대용량의 데이터 자원을 광대역 통신망을 통해 공유한다. 이러한 그리드 환경은 물리적 네트워크인 인터넷 상에서 구현되기 때문에 대용량의 데이터를 전송하는데 많은 시간이 소요된다. 이러한 문제를 극복하기 위해서 여러 가지 복제 정책들이 제안되었는데, 기존의 데이터 그리드 복제 정책은 실제 인터넷의 구조를 고려하지 않고 논리적인 토폴로지를 바탕으로 제안되었기 때문에 실제 구축된 데이터 그리드에서 최적의 성능을 기대할 수 없다. 그리드에서 데이터 접근시간은 물리적 네트워크인 인터넷의 구조에 의해 가장 큰 영향을 받기 때문이다. 본 논문에서는 인터넷 구조 기반의 새로운 데이터 그리드 복제 정책으로 RSIA(Replication Strategy based on Internet Architecture) 복제 정책을 제안한다. 이 정책은 인터넷의 각 요소들 사이에 존재하는 구조적인 계층성을 고려하여 데이터 복사본을 배치하고, 데이터 전송 시 대역폭의 병목 구간을 피함으로써 시스템의 성능 저하를 줄인다. 본 논문에서는 시뮬레이션을 통하여 제안하는 RSIA가 기존의 복제 정책에 비해 데이터 그리드의 성능 향상 면에서 우수함을 보인다.