• Journal of Communications and Networks
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• 제8권1호
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• pp.49-58
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• 2006

One of the first decisions that a radio network designer must take is the location of base stations and the distance between them in order to give the best coverage to a region and, possibly, to reduce deployment costs. In this paper, the authors give an insight to this matter by presenting a possible solution to a real problem: Planning the base stations layout for a universal mobile telecommunications system (UMTS) in the city of Barcelona. At the basis of this problem, there is the interdependence between coverage and capacity in a wideband-code division multiple access (W-CDMA) system, which is a new element in the planning of BS layout for mobile communications. This aspect has been first treated with an analytical study of the cell coverage range for a specific environment and service. The achieved results have been checked with the help of snapshot simulations together with a geographical information system (GIS) tool incorporated in the simulator that allows to perform analysis and to visualize results in a useful way. By using the simulator, it is also possible to study a more complex environment, that of a set of base stations providing multiple services to a large number of users.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.78-80
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• 2006

High speed electric trains have nonlinear loads including converters and inverters for the control synchronous motors. Harmonic field measurements have shown that the harmonic contents of a waveform varies with time. Direct application of the harmonic assessment to the snapshot measurements would result in ambiguous conclusions depending on which instant is sampled. A cumulative probabilistic approach is the most commonly used method to solve time varying harmonics. This paper provides an in depth analysis on harmonics field measurement of the high speed electric train loads, harmonics assessment by the international harmonic standards IEC 61000-3-6 and IEEE Std. 519-1992, and harmonics simulation using EDSA program for the case study.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 D
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• pp.1811-1812
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• 2006

본 논문은 공간상에서 움직이는 다중신호원의 신호 도달 방향 추정과 신호원이 보낸 신호를 다중 센서 어레이를 이용하여 판별하는 문제를 다룬다. 일반적으로 정지하고 있는 신호원의 방향 추정은 어레이에서의 출력 방정식의 방향 벡터들이 시불변인 상수이기 때문에 잡음환경 하에서도 샘플링된 벡터(Snapshot) 수가 늘어날수록 훨씬 정확하게 방향 추정이 가능하지만 신호원이 움직이는 경우에는 신호원의 방향이 변하게 되어 결국 어레이 방정식의 방향 벡터들이 시변이므로 추정값의 분산(variance)이 커지게 되어 정확한 추정이 어렵게 된다. 이러한 경우에 대한 정량적인 분석 예는 드물어 실제 여러 가지 추정 기법들의 특성이 어떻게 나타나는지 가늠하기가 어렵다. 따라서 본 논문에서는 이러한 경우에 대한 시나리오 예를 설정한 후 이 시나리오에 따른 랜덤 가우시안 잡음 하에서의 수치 데이터 모델을 생성하여 수신기에서는 미지의 값인 이 데이터에 대해 기존의 DOA 추정 기법을 이용하여 추정을 수행하여 그 정량적인 결과들을 계산해 봄으로써 시변인 경우에서의 그 성능을 판단해 보기로 한다.

• 한국콘텐츠학회논문지
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• 제11권9호
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• pp.9-16
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• 2011

웹 자원은 아직 수집, 보존, 활용에 대한 방안이 없어서 일정 기간의 서비스가 끝나면 사라져 버리는 문제점이 있다. 이런 웹 자원들은 중요성에 관계없이 주기적 또는 비주기적으로 갱신되거나 소멸된다. 따라서 웹 자원을 수집하고 보존하기위한 웹 아카이빙 시스템이 요구되고 있다. 이러한 웹 자원들을 주기적으로 수집하기 위해서는 웹 아카이빙 전용 크롤러의 개발이 필요하다. 따라서 본 연구에서는 웹 자원의 아카이빙 수집을 위해서 사용되는 기존의 웹 크롤러의 장단점을 분석하고 이것을 이용하여 웹 정보자원을 수집하기 위한 가장 적합한 수집 도구 시스템을 연구하고 개발하였다.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2002년도 추계공동학술대회 정보환경 변화에 따른 신정보기술 패러다임
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• pp.350-362
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• 2002

높은 가용성 확장성, 시스템 성능의 요구를 만족시키기 위해 SAN(Storage Area Network)이 등장했다. SAN을 보다 효과적으로 활용할 수 있도록, 대부분의 SAN 운영체제들은 SAN에 부착된 물리적 저장장치들을 가상적으로 하나의 커다란 볼륨으로 보이게 하는 저장장치 가상화 개념을 지원한다. 저장장치 가상화의 핵심적인 역할을 하는 것이 바로 논리볼륨 관리자이다. 논리볼륨 관리자는 논리 주소를 물리 주소로 매핑시킴으로서 저장장치 가상화를 실현한다. 이 논문에서는 논리볼륨 관리자를 위한 효율적이고 유연한 매핑 기법을 설계하고 구현한다. 이 논문의 매핑 기법은 특정 시점의 볼륨이미지를 유지할 수 있는 스냅샷과 시스템을 정지시키지 않고 SAN에 디스크를 추가 또는 삭제할 수 있는 온라인 재구성 기능을 지원한다.

• 한국의류학회지
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• 제28권11호
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• pp.1415-1425
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• 2004

The purpose of this study was to analyze a theoretical frame of expressional area, the characteristics and the effects which is applied to fashion illustration by metonymic theory. The theoretical frame of expressional area was analyzed by category analysis and 150 fashion illustrations from 1900 to 1999 were analyzed by contents analysis. The results of this study were as follows: The expressions of metonymy were categorized by close-up, realistic expression, omission, borrowing of past style, simplification and deconstruction. First, close-up was presented as emphasis of small part of fashion by cutting the scenes, snapshot, emphasis, etc. Second, realistic expression was presented as description of related circumstance with fashion message through perspective and realistic description of circumstance related to figures. Third, omission was presented as seeking of essential core by removing color, pattern, texture or by omitting body and as emphasis of communication about dominant fashion message. Fourth, borrowing of past style was presented as reminding us of background of the past. Fifth, simplification was presented as using of form or color to alleviate tension of object and to restore the essential reality. Sixth, deconstruction was presented as fragmenting of image, flattening of body and clothing, weakness of form, and strength of color. In conclusion, metonymy made by experience system of thinking based on the reality, have extended expressional territory in pre-existing fashion illustration. And these ways not only will provide fashion image as illustrator's subjective intention and theoretical system of expression of message, but also will be useful way to strengthen communication for easier interpretation of fashion illustration.

• 기술경영경제학회:학술대회논문집
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• 기술경영경제학회 1998년도 제13회 하계학술발표회 논문집
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• pp.208-215
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• 1998

Since the advent of conceptual prototype and seminal application, the notion of national systems of innovation(NSI) has drawn an increasing recognition. Although the morphological entanglement is still ubiquitous and the theoretical underpinning is fragile, NSI seems to be the last step toward an increasingly complex and encompassing concept of innovation research. Inevitably, NSI necessitates the comparative analysis in that it normatively attempts to draw best practices. Unfortunately, national profiles are too complex and diverse to derive a unified, concrete representation of the system, posing the problem of defining and modelling NSI for international comparison. This paper aims at providing an inductive taxonomy of NSI based on R&D structure of OECD member economies. Based on the similarity among national profiles, clustering method was applied to identify seven clusters such as (1) enterprise-government funding and enterprise-education performing group, (2) enterprise-government funding and balanced performing group, (3) balanced funding and enterprise-education performing group, (4) balanced funding and performing group, (5) enterprise-dominating group, (6) government-education dominating group and (7) government-education funding and education performing group. This paper by nature is descriptive and exploratory. R&D structure represents a static snapshot of innovative performance since it accounts for only the input side of NSI and thus may not offer convincing explanations of the holistic innovation system. A more detailed and extensive analysis on the economic/technological performance across clusters will shed light on the promising avenue to future research.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.173-176
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• 2008

Lake studies play an important role in water management, ecology, and other environmental issues. Typically, monitoring lake levels is the first step on the lake studies. However, for the Prairie Pothole Region (PPR) of North America having millions of small lakes and potholes, on-site measurement for lake levels is almost impossible with the conventional gage stations. Therefore, we employed Geographic Information System (GIS) and remote sensing approach with the Shuttle Radar Topography Mission data to extract lake levels. Several image processing techniques were used to extract lake levels for January, 2000 as a one-time snapshot which will be useful in historic lake level reconstruction. This study is associated with other remote sensing datasets such as Landsat imagery and Digital Orthophoto Quadrangle (DOQ). In this research, firstly, image processing techniques like FFT filtering, Lee-sigma, masking with Canny Edge Detector, and contouring were tested for lake level estimation. The semi-automated contouring technique was developed to accomplish the bulk processing for large amount of lakes in this region. Also, effectiveness of each method for bulk processing was evaluated.

• 한국정보시스템학회지:정보시스템연구
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• 제17권4호
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• pp.281-299
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• 2008

An online game is popular topic due to the increased total online game market volume nowadays. Even though many studies on an online game are released, most studies have used survey method that reveal only section of the situation like a snapshot. For this reason, previous studies have a little limitation that does not show dynamically changing issues like a product life cycle and change in customer's satisfaction. Because of this, we researched on an online game with the system dynamic model which can show dynamic simulation to analysis time series data. We chose MMORPG (Massively Multi-play Online Role Playing Game) in sort of an online game because it has many absorbing factors and enthusiastic users. We assumed that the game developer is ready for updated version game and release that periodically and focused on dormant users who used to be enthusiastic about MMORPG and designed simulation model which analyze how to influence of update and CRM strategy on users. The simulation results showed that the update has positive influences to gather new users and hold established users and CRM strategies help to prevent dormant users from transferring to rivals to offer them re-absorbing factors. Through this study, we confirmed importance of update on a online game and suggested the necessity to introduce CRM strategy in an online game market.

• 한국정보처리학회논문지
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• 제5권5호
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• pp.1083-1097
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• 1998

기존의 GIS(Geographic Information System)는 실세계에 존재하는 지형객체의 속성정보와 공간정보를 취급하는 소프트웨어이다. 이 시스템은 고정된 데이터를 다루기 때문에 시간변이 정보를 저장 관리하여 사용자에게 제공할 수 없으며 제공한다 하더라도 제한적이며 질의 표현과 처리에 많은 어려움을 갖는다. 따라서 이 논문에서는 시간지원 지리정보 시스템을 계층적 접근 방법을 기반으로 기존의 지리정보 시스템이 제공하는 공간에 시간 개념을 확장하여 시간에 따라 변화하는 공간객체의 이력을 지원하는 시공간 통합 데이터 모델을 연구하였다. 즉, 시공간 데이터베이스 구조의 변화에 대한 데이터 구조를 설계하고, 시간변이 공간연산과 이에 따른 시간지원 공간연산자를 제안한다.