• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.10
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• pp.1327-1333
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• 2018

Numerical analysis has the advantage that no actual flow pathways need to be formulated, making this technique especially useful for simulation analysis such as pathway design. However, it does require that the complete physical parameters of the fluid and the complete boundary conditions be known. If any of them are unknown, either the calculation will become impossible, or even if the calculation does converge, the reliability of the result will be low. Therefore, a means of more accurate acquisition of flow information is required. In this paper, we present techniques for estimating flow field from a constraint equation for image information and velocity field, based on the image intensity changes accompanying the motion of dye in waterway. In the equation, we entered a stabilizing term to suppress estimation error. We show the effectiveness of our method through experiments with generated and real images of a Karman vortex.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.69-69
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• 2020

수자원 확보 및 홍수 대응을 위해서는 정확한 강우정보를 바탕으로 한 효율적인 댐 운영이 필요하다. 그러나 댐이 위치한 지역은 산지지역으로 강우관측소 밀도의 지역적인 편차로 인해 지상 관측 강우자료 활용 시 강우 정보의 정확도 확보에 한계가 있다. 또한, 강우의 시·공간적 변동성 심화로 기존의 강우계만으로는 정확한 강우량 추정이 어려워 이를 홍수기 댐 운영의 기초정보로 활용 시 합리적 댐 운영에 한계가 있다. 댐 운영 시 강우 관측정보는 댐 유입량 산정을 위한 강우-유출해석 모형의 입력 자료로 활용되기 때문에 강우량 자료의 정확도 확보가 무엇보다 중요하나, 현재 댐 운영에 필요한 강우 관측정보로는 지상우량계 자료가 주로 활용되고 있어 이를 보완하고자 일반적으로 강우의 공간분포를 관측할 수 있는 고해상도 레이더 강우 정보가 활용되고 있다. 본 연구에서는 전력생산(발전) 및 용수공급, 홍수조절 기능을 고려하여 운영되고 있는 한국수력원자력(주)의 수력발전용댐(팔당, 의암, 춘천, 화천, 청평, 도암, 괴산, 섬진강, 보성강댐)에 활용할 수 있도록 환경부 합성레이더 자료를 바탕으로 레이더 강우정보를 산출하고, 레이더 강우의 정확도 향상을 위해 고도영향을 고려한 레이더 강우 보정기술을 개발하고자 한다. 적용한 기법은 강우장의 공간적 구조는 레이더 자료로 획득하고, 강우량은 강우계 관측정보를 합성하는 조건부합성기법을 기본으로 하며, 고도 영향을 고려할 수 있도록 강우분포장 생성 시 주변수를 강우로, 이차변수를 고도로 정의한 표준화된 정규공동크리깅을 활용한 기법이다. 본 연구를 통해 산출된 레이더 강우를 댐 유입 측면에서 기존의 보정기법과 비교하여 정확도를 검토하고, 댐 운영에 활용할 수 있도록 유역평균강우량 정보를 산출하고자 한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.2
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• pp.157-168
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• 2013

The social network service is the bidirectional media that all of the users are be able to directly produce, process, and distribute the information without distinction of the producer and consumer. Over increasing the users rapidly, the users are be able to obtain and share the various information, but the problems occur due to the spread of unreliable information on the service. Moreover, it is spreading the problems violating the privacy and decreasing the reliability of the users by exploiting the open environment. Therefore, sensitive information can be delivered only to users which information producer can trust, and the users should get the information from the trustworthy users. Due to this necessity, it needs the efficient method can evaluates the reliability of the users. In this paper, we define the reliability in the service, make the trust parameter by using the function of the service, and propose the dynamic user reliability evaluation scheme evaluating the reliability of users. We draw the trust range on the reliability of users by analyzing the proposed reliability evaluation scheme.

• Journal of KIISE:Software and Applications
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• v.28 no.11
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• pp.864-873
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• 2001

In this paper, a new approach to building a registration authority for issuing PKI-based certificates is presented to make the process of identifying an individual more secure and reliable by utilizing human iris recognition technology. The tasks of the proposed system associated with the manipulation of irises except for the general functions of registration authorities can be categorized into three modules, the acquisition of iris images, the registration of iris information, and the verification of users by means of iris patterns. The information among the three modules is safely exchanged through encryption and decryption with a symmetric cryptographic method. As a feature extraction method for a given iris image, a wavelet transform is applied to represent a feature vector with a small dimension of information obtained by subsampling an image corresponding to lower frequency bands successively without loss of information. Through the experiments on human iris recognition technology we proposed and applied to the registration authority, the potential of biometric technology in various applications is confirmed.

• The Transactions of the Korea Information Processing Society
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• v.4 no.2
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• pp.409-429
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• 1997

Problems encountered during software development or pteration nay result from defects in the software,ghrdware,or their oterations.Because of their diversity,the determination of the sources of a problem and its corrective adtion requires a centrally controlled system for monitoring provlems and detemining systematiccauses. In the paper,the SPR/SCR management system was developed and applied for the collection and analysis of the error data,process data and product data delected by each phasd in SDLC.There are four objectibes in the SPR/SCR management system.The first is to assure that software errors are documented,corrected,and vot forgottem. The second is to assure that SPR.are assessed for their validity.The third is to provide feedback on SPR status to the developer and the user.The fourth is ot prvide data for measuring and prediciting sofware quality and reliability.These goals could be satisfied by the application of the SPR/SCR mangement system.Also,the accomplishment rate of software reliability,criterion of test completion,estimation of release time, efficient development and management can be reflected by applying the SPR/SCR management system.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.2
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• pp.255-266
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• 2022

Messenger applications applied end-to-end encryption on their own to prevent message exposure to servers. Standardization of a group messaging protocol called Message Layer Security (MLS) with end-to-end encryption is being discussed for secure and efficient message communication. This paper performs safety checks based on the operation process and security requirements of MLS. Confidentiality to a middleman server, which is an essential security requirement in messenger communication, can be easily violated by a server administrator. We define a server administrator who is curious about the group's communication content as a curious admin and present an attack in which the admin obtains a group key from MLS. Reminds messenger application users that the server can view your communication content at any time. We discuss ways to authenticate between users without going through the server to prevent curious admin attacks.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.4 s.22
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• pp.69-76
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• 2002

Nowadays information is very important for Civil Engineering. This information is acquiredmostly via Surveying & Geo-spatial Information System. Also this information is close to the ITS(Intelligent Transformation System), Navigation, Facility Management, and Digital Mapping, etc and applicable to versatile fields from now on. And in surveying fields, GPS satellites are introduced newly and play a great rules. In this study, RTK(Real-Time Kinematic GPS), one of the positioning technology with GPS satellites, is used for the production of Plane Figure of Campus. The results shows that it is possible to extract the information for some part of a flowerbed and road, but not so for the buildings surrounded. Therefore this give occasion to the a lowering of work effectiveness over the total work-flow. So at such a time, it will be expected that the supplementary systems such TS(Total Station), Plane-table, and theodolite, etc have to be used.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.4
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• pp.97-110
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• 2007

A laser scanning technique has been attracting much attention as a new technology to acquire location information. This technique might be applicable to a wide range of areas, most notably in geomatics, due to its high accuracy of location and automation of high-density data acquisition. A alignment information extraction system on highway has been developed in this study by utilizing the advantages of the laser scanning technique. The system can accurately interpret the alignment information of highway and can be applied to actual works. To develop the alignment information extraction system on highway, an algorithm that can automatically separate a horizontal alignment into a straight line, a transition curve, and a circular curve was developed. It can increase its efficiency compared to the conventional methods. In addition, an algorithm that can automatically extract design elements of horizontal and vertical alignments of highway was developed and applied to an object highway. This yielded higher practicality with more accurate values compared to those from previous studies on the extraction of design elements of highway alignment. Furthermore, the extracted design elements were used to perform a virtual driving simulation on the object highway. Through this, data were provided for a visual judgment for judging visually whether the topography and structures were harmonized in a three-dimensional manner or not. The study also presents data that can serve as a basis to determine highway surface freezing sections and to analyze three-dimensional sight distance models. Through the establishment of a systematic database for diverse data on highway and the development of web-based operating programs, an efficient highway maintenance can be ensured and also they can provide important information to be used when estimating a highway safety in the future.

• Journal of Advanced Navigation Technology
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• v.16 no.6
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• pp.988-996
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• 2012

Assuming perfect channel state information (CSI), the conventional interference alignment (IA) algorithm in the uplink cellular system suppresses inter-cell interference (ICI) by aligning ICI to a randomly selected reference vector. However, IA in practice relies on limited feedback between base stations and users, resulting in residual ICI. In this paper, we propose the optimization of the reference vector that minimizes the upper-bound of residual ICI power. Secondly, the iterative IA that designs the direction of transmit and receive filter is proposed to minimize the residual ICI as well as maximize the desired signals. Moreover, we propose the user scheduling method combined with proposed IA schemes which provides the multiuser diversity gain in multi-cell environments. Finally, the performance gain of the proposed IA algorithms compared with the existing IA are analyzed and demonstrated by simulation results.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.999-1004
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• 2006

본 연구에서는 다양한 개념 패싯과 관계 패싯들을 수용한 범용 과학기술 시소러스 구축용 웹 기반 워크벤치 개발에 대해 기술한다. 기존 국내 시소러스 구축용 워크벤치들이 제공하는 기본적인 용어 관계구축 기능을 확장하여 개념 패싯, 범주 관계 패싯, 의미역 관계 패싯, 속성 관계 패싯 및 속성 키워드 처리 기능을 원활히 제공할 수 있는 사용자 중심적 워크벤치를 개발함으로써 시소러스 상의 개념들에 대한 효율적인 구축이 가능하도록 한다. 또한 시멘틱 웹 상의 온톨로지 영역에 보다 근접한 고도화되니 시소러스 구축을 위해 용어들을 개념화시키고, 개념간의 다양한 관계를 설정하는 프로세스 중심적 설계로 분야 적합성이 높은 정보 처리 기반을 갖춘다. 궁극적으로 여러 마이크로 시소러스들을 통합하여 운용할 수 있는 복합 모델을 구축하는 것을 목표로 하고 있다. 이러한 목적에 부합하는 시스템 구현을 위해 CBD(Component Based Development) 개발 방법론으로 MSF/CD를 이용하였으며, 분산 환경에서 이기종간의 데이터 교환을 용이하게 하기 위하여 웹 서비스 (XML Web Services)를 이용하였다. 또한 시멘틱 웹 기반 연구자 간 협업 지원 서비스 구현을 위한 확장 검색용으로서도 활용할 수 있도록 하였다. 시소러스 반출은 CSV, XML 및 RDF를 모두 지원할 수 있도록 함으로써 다양한 사용자 요구 사항에 부합할 수 있도록 하였다. 시소러스 브라우징을 시각화 기반의 3단계 구조를 가진 플래시로 구현하여 사용자가 쉽게 시소러스를 탐색하고 분석할 수 있는 기반을 제공하였다. 또한 다양한 검색 요구를 만족시키고자 기본 검색, 고급 검색, 메타 검색을 선택할 수 있도록 하며, 개념 편집 및 시소러스 브라우징과 연동시켜 효율적인 시소러스 구축이 가능하도록 하였다. 본 연구의 워크벤치를 이용하여 구축된 시소러스는 기존 시소러스들에 비해 사용자가 보다 폭넓은 의미 기반 검색을 수행할 수 있도록 함으로써 다각적인 정보를 쉽게 획득할 수 있는 기반을 마련하고 있다는 데 의의가 있으며, 다국어 시소러스 및 다중 시소러스를 수용할 수 있는 방향으로 발전시킬 계획이다.