• 디지털융복합연구
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• 제14권5호
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• pp.341-348
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• 2016

VPN은 인터넷망을 이용하므로 데이터를 암호화하는 보안기술이 뒷받침되어야 하며 보안성에 대한 확신을 줄 수 있도록 표준에 기반을 둔 평가 기술이 뒷받침되어야 한다. 그러므로 연관된 표준을 기반으로 VPN의 보안성을 평가할 수 있는 방법을 체계화할 필요가 있다. 따라서 본 연구에서는 정보보호시스템의 인증을 위한 평가기준인 CC(Common Criteria)와 소프트웨어 품질평가 표준인 ISO의 보안성(기밀성, 무결성, 부인방지, 책임성, 인증성) 평가 부분을 접목하여 이를 통합한 보안성 평가 모델을 구축하고자 하였다. 이를 위해 VPN의 기반 기술과 보안성에 관한 품질 요구사항을 분석하여 두 국제표준의 품질특성과의 연관성을 고려한 평가모델을 개발하였다. 이를 통해 VPN의 보안성 품질수준을 평가하는 융합 모델을 구축할 수 있을 것으로 사료되며, 향후 VPN에 대한 평가사례의 축적을 통해 평가모델의 적합성과 타당성을 제고할 필요가 있다.

• 정보처리학회논문지C
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• 제8C권5호
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• pp.683-692
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• 2001

본 논문에서는 인터넷 망을 위한 SNMP(Simple Network Management Protocol)를 이용하는 망 관리 시스템과 OSI 망을 위한 CMIP (Common Management Information Protocol)을 사용하는 망 관리 시스템을 상호 연동할 수 있는 통합 망 관리 에이전트 (agent)를 설계, 구현하였다. 서로 다른 두 망 관리 시스템을 통합하기 위하여 본 연구에 앞서 수행한 MOVI(Managed Object View Interface) 개념을 이용하였다. 통합 망 관리 에이전트 설계를 위한 3가지 모델을 검토하고 이 모델들의 장단점을 비교하여 적합한 모델을 선택 하였다. 선택한 모델을 구체화할 수 있는 통합 망 관리 에이전트의 논리적 구조와 구체적인 구현방법 그리고 각 모듈별 작동에 대하여 언급하였다. 본 연구에서는 기존의 망 관리 시스템인 osimis와 ucd-snmp 시스템을 참조 모델로 이용하였다. 본 연구를 통하여 인터넷 망과 OSI 망을 망 관리적 측면에서 연동할 수 있을 뿐 아니라 앞으로 MOVI 개념에서 언급하고 있는 것과 같이 새롭게 정의될 수 있는 망 관리 시스템과의 연동에 대한 확장도 가능하다는 장점을 가진다.

• 한국인터넷방송통신학회논문지
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• 제8권4호
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• pp.59-65
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• 2008

본 논문은 휴대용 멀티미디어를 위한 저전력 H.264 디블록킹 필터를 제안하였다. H.264 디블록킹 필터는 총 8개의 입력 픽셀에 대한 각각의 필터링 연산 과정을 필요로 하며, 각 필터링 과정에서 p, q 픽셀에 대해 공통 구조를 가지고 있다. 이 때 쓰이는 공통의 필터계수와 레지스터를 공유함으로써, 적은 게이트로 구현하였다. 또한 많은 연산을 필요로 하는 필터링 연산을 특정한 조건을 이용하여, 조건에 만족하면 일부 또는 전체의 필터링을 수행하지 않음으로써 저전력의 효율적인 구조를 설계할 수 있다. 제안한 H.264 디블록킹 필터 구조는 기존 논문들의 핵심 필터링부분과 비교하여 각각 33.31%와 10.85%의 게이트 감소효과를 나타내었다. 또한 본 논문의 전체 블록은 삼성 0.35um 표준 셀 라이브러리 공정을 사용하여 구현하였으며, 최대 동작 주파수는 108MHz, 최대 처리능력은 CCIR601 형식에서 33.03 frame/s이다.

• 상하수도학회지
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• 제30권3호
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• pp.271-278
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• 2016

Recently, reverse osmosis (RO) is the most common process for seawater desalination. A common problem in both RO and thermal processes is the high energy requirements for seawater desalination. The one energy saving method when utilizing the osmotic power is utilizing pressure retarded osmosis (PRO) process. The PRO process can be used to operate hydro turbines for electrical power production or can be used directly to supplement the energy required for RO desalination system. This study was carried out to evaluate the performance of both single-stage PRO process and two-stage PRO process using RO concentrate for a draw solution and RO permeate for a feed solution. The major results, were found that increase of the draw and feed solution flowrate lead to increase of the production of power density and water permeate. Also, comparison between CDCF and CDDF configuration showed that the CDDF was better than CDCF for stable operation of PRO process. In addition, power density of two-stage PRO was lower than the one of single-stage. However, net power of two-stage PRO was higher than the one of single-stage PRO.

• Korean Journal of Geomatics
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• 제2권1호
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• pp.75-82
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• 2002

The information system fields of spatial applications have rapidly grown during the last decade in Korea. Spatial data has been produced for a variety of systems without common standards until national GIS Committee defined the data exchange formats among spatial databases in the middle of 1990's. It aimed at promoting data sharing between the different systems in similar application fields. However, a considerable number of databases built prior to the introduction of the standards are not yet standard compliant but still play the roles of the main producers/consumers in the data collection field such as early developed huge AM/FM systems maintained by governmental organizations. The strong autonomy of these databases keeps their own data models, formats and descriptions from being standardized, which leads the sharing to a more difficult stage. Sharing is another way of data acquisition with least efforts and time away from direct collection. A data clearinghouse is the core module which directs users to the relevant data resources. The contents of datasets should be described with predefined metadata standards for precise indexing. Moreover, a number of technical problems have to be resolved for the common use of data between heterogeneous spatial database systems. However, the technical issues can be covered by the present information technologies. The difficulties persist in the political/institutional issues. Institutional issues are derived from the diverse sources such as political background, governmental policies, related laws and/or regulations. The paper will firstly make an analysis of current situation in terms of Korean policies, laws and regulations, secondly abstract the institutional issues from the situation analysis, lastly present guidelines for promoting spatial data sharing in Korea.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2009-2014
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• 2007

Hydrogen is a fuel of fuel cell system, which has powerful explosion possibility. Hence, the fuel cell system needs safety evaluation to prevent risk of hydrogen leakage. We use a actual size chamber of a common fuel cell module to analyze hydrogen. Hydrogen injection holes are located in lower part of the chamber in order to simulated hydrogen leakage. The hydrogen sensor can detect range of 0${\sim}$4%. Since the hydrogen gas, of which leaked amount is controled by MFC, are injected at the bottom holes, the transient sensor signals are measured. At a condition of 10cc/s of hydrogen leakage, the sensor detects hydrogen leakage after 22sec and there is also several seconds of time delay depending on the position of the sensor. This experimental data can be applied for the design of the hydrogen detection system and ventilation system of a residential fuel cell system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.346-349
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• 2004

The teleoperation system applies all of the industrial fields due to the development of the network infrastructure. It is one of the indispensable elements for controlling the robot at a remote sight and monitoring the limit or unknown environment. The common teleoperation robot system is what has the visual module to supply the network system and realistic UI to the existed robot system. Therefore, remarked that the fusion between modules and transmission of visual data the remarked the important element to improve the robot application in the various environments. Delay of development time by robot platform and noneffective communication among developers are also problem to approach. In this paper we propose the independent teleoperation system. The main application language is JAVA in this system, which is applied JAVA API like JNI and JMF to construct the effective teleoperation system. The system has the both side communication system between sever and client as a basic structure. The visual data that is attached the robot at a remote sight is captured by JMF API and then is transmitted to the web browser called client by RTR protocol. JNI is used to connect between JAVA and the lower part application (sensor fusion, motion control.) of the robot programmed by various Native languages. The proposed system is the application that can perform the elements, for instance transmission of visual data, the fusion of various native application modules and the effective network communication, with any platform.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.131-134
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• 2005

Recently, RF systems have rapidly grown with the extension of the mobile communication service The mobile service companies are providing the satellite broadcasting and common usage are expected. Coinciding with current trend, the development of improved satellite DMB (Digital Multimedia Broadcasting) tuner is required. To improve the receiving sensitivity under the poor communication circumstance, It is necessary to design the LNA (Low Noise Amplifier) with outstanding low noise characteristic and the BPF (Bandpass Filter) to transmit only desired signal without distortion and loss. Besides high reliability, the miniaturization and lightweight are required for design of mobile terminals. In this study, we designed and fabricated DMB SIR-type BPF which operates at 2642 MHz and is embedded in the substrate using LTCC. As a result, we obtained the passband insertion loss of 2.4 dB and the passband ripple of 0.08 dB. So this DMB SIR-type BPF is applicable to RF module of a satellite DMB tuner.

• 한국게임학회 논문지
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• 제15권6호
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• pp.7-16
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• 2015

게임 플레이어와 게임 세계 아바타 사이의 일체감 향상을 위하여 게임 플레이어의 신체 정보를 측정하고 이를 사용하여 게임 캐릭터의 외양 및 행동을 표현하는 기법을 제안한다. 신체 정보 측정을 위해서 하드웨어 모듈을 제작하여 체온 측정이 가능하도록 하였다. 실제 적용 실험을 위해서 지하철 공간을 무대로 한 일상생활 주제의 공포 게임을 제작하였다. 일상생활에서 자주 접하는 공간을 선택하여 일반인에게 익숙한 환경에 더 쉽게 적응하고 몰입할 수 있게 하였다. 게임 플레이어로부터 측정된 센서 데이터를 게임 공간의 캐릭터에 적용한 결과 플레이어의 신체 측정 데이터를 반영한 게임 구성이 효과적으로 수행됨을 확인하였다.

• 한국유체기계학회 논문집
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• 제1권1호
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• pp.7-16
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• 1998

An interactive mode of grid generation system has been developed for a Navier-Stokes design procedure of axial flow compressors. The present grid generator adopts the multiblock H-grid structure, which simplifies the creation of computational grids about complex turbomachinery geometries and facilitate the manipulation of multiple grid blocks for multirow flow fields. The numerical algorithm adopts the combination of the algebraic and elliptic method to create the internal grids efficiently and quickly. The system consists of four separated modules, which are linked together with a common graphical user interface. The system input is made of the results of the preliminary design. The final grids generated from each module of the system are used as the preprocessor for the performance prediction of the two-or three-dimensional flow simulation inside the blade passage. Application to the blade design of the LP compressor was demonstrated to be very reliable and practical in support of design activities. This customized system are coupled strongly with the design procedure of the turbomachinery cascades using the Navier-Stokes technique.