• Journal of Energy Engineering
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• v.21 no.1
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• pp.68-74
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• 2012

Sub-bituminous coals have been used increasingly in coal-fired power plants with a proportion of over 50% in the blend with bituminous coals. As a result, the unburned material in fly ash has increased and is causing problems in utilizing the fly ash as an additive for concrete production. In this study, analysis of fly ash obtained from a 500 MWe power plant was carried out and unburned material in the fly ash found to be soot. The coals used in the plant were analyzed with CPD model to investigate the sooting potential depending on the coal type and blending ratio.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.11
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• pp.2497-2506
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• 2010

Smart power grid is targeting to improve grid operation by integrating existing power IT technologies in the jeju smart grid field test. Real-time two-way communication and interoperability in power grid are essential to smart power grid. Adopting smart grid will increase security vulnerabilities in power grid by increasing the number of wireless sensors and the chances of the external exposure of communication networks. In addition, hackers can cause chaos in the power grid system with eavesdropping and forgery attacks in communication networks. Smart power grid is one of the most important systems in deploying smart grid, and it is important to design security system systematically since smart grid can be seriously damaged when problem occurs. In this paper, local and global smart grid security standard and security vulnerabilities in power grid are reviewed, and 2 level smart grid service model is proposed.

• Economic and Environmental Geology
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• v.17 no.1
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• pp.49-55
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• 1984

This paper describes three-dimensional (3-D) standard curves for conductive dipping buried bodies in induced polarization (IP) method. Dipole-dipole IP responses for the dipping bodies are calculated by the numerical modeling technique using an integral equation solution. Dip angles of the bodies are 0, 20, 45, 70 and 90 degrees, respectively. The horizontal (0-degree dip) and vertical (90-degree dip) bodies produce symmetrical patterns of IP responses. The dipping bodies of 20, 45 and 70 degrees, however, produce asymmertical patterns, with the highest IP contours dipping in the direction opposite to the bodies in pseudo-sections. The most remarkable asymmetrical pattern appears in the model of 20-degree dip. It is difficult to distinguish the body of 70-degree dip from that of 90-degree dip on the basis of dipole-dipole IP data. The IP pattern in pseudo-sections varies when the line moves away from the center of the body along strike, with the anomaly deeper and smaller in amplitude. IP maps seem to be more useful than IP pseudo-sections in predicting the location of target.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06c
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• pp.127-129
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• 2006

최근 대부분 기업들 환경에서의 정보 시스템들은 지역적으로 분산되어 있으며 다양한 형태로 구성되어 있으므로, 사용자 의사 결정을 지원하는데 필요한 통합된 정보를 얻는 것은 어려운 일이다. 따라서 이러한 문제를 효율적으로 정보 검색에 적용하기위해 사용자에게 단일 인터페이스를 제공하고, 이기종 시스템들 간에 구축된 데이터베이스 시스템들은 각각 독립성을 유지하면서 하나의 인터페이스처럼 투명성을 제공할 필요성이 있다. 이를 위해 ISO/IEC 11179에서 연구 중인 XMDR의 개념을 이용하여 정보검색에서 발생하는 "의미적 상호운용성(semantic interoperability)"이라는 문제점을 해결하고 이 XMDR에 지식 인스턴스 계층을 통한 지식공유를 가능하게 함으로써 단순 검색의 한계점을 극복할 수 있도록 한다. 본 논문에서는 데이터 표현에 사용되는 명칭, 속성, 관계성에 대한 이질적인 문제를 해결하기 위한 표준 온톨로지, 각 레거시 시스템을 연결하는 중간자(mediation)역할을 수행하는 로케이션 온톨로지, 지식공유가 가능하도록 하는 지식 인스턴스 계층으로 구성하는 방법을 제안한다. 또한 지식 인스턴스 계층은 협업적인 검색 환경하에서 각각의 정보시스템에서 다양한 형태의 지식을 공유 및 통합에 있어 구조화 되지 않은 지식들을 어떻게 공유할 것인가에 대한 개념적인 모델을 제시한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.7
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• pp.1425-1431
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• 2005

In this paper, we consider the ISR(Intelligence, Surveillance, and Reconnaissance) system which collects the imagery intelligence from an airplane and CDL(common data link) communication system which transports the information obtained by the ISR system. The IMINT(imagery intelligence) consists of MPEG-2 transport stream packets and they transmit through CDL. We have some simulations for communication performances of CDL and show performance improvements using convolutional coding. We have compared BER performances under AWGN channel and fading channel which is caused by the velocity of an airplane.

• The Journal of Society for e-Business Studies
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• v.17 no.4
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• pp.209-219
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• 2012

Objects such as products, product reviews, and user profiles are important in e-commerce domain. Vector is one of the most widely used object representation scheme. Information of e-commerce objects may be modeled by vectors in which the featured values are assigned to various dimensions. E-commerce objects are in general quantitatively large while some are similar or even same in reality. It Plays, therefore, an important role to measure the similarity between objects. In this paper, we survey the state-of-the -art vector similarity measures. Similarity measures are analyzed to feature the algebraic characteristics and relationship of those, and upon which we classify the related measures accordingly. We then present such features that standard vector similarity measures should convey.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.3
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• pp.107-122
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• 2006

The main objective of this study is to develop a web-based Geographic Information System (GIS) application, IGIS(Integrated Groundwater Information Service System), for efficient management of groundwater data. This integrated system includes various groundwater measurements, monitoring data, well data, hydrogeochemical data, hydrogeological maps and diversely analyzed results including time series analysis data for water levels and quality. It will be used efficiently for local government officers to manage groundwater within their districts and also for drillers and investigators to develop wells and assess groundwater conditions. This web-based GIS system was implemented firstly for Cheonan and Daegu city. As a result, the system makes the efficient management, distribution and utilization of groundwater data possible by web-based GIS technology.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.5
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• pp.114-124
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• 2014

HEVC is a state-of-the-art video coding standard developed by JCT-VC. HEVC provides about 2 times higher subjective coding efficiency than H.264/AVC. One of the main goal of HEVC development is to efficiently coding UHD resolution video so that HEVC is expected to be widely used for coding UHD resolution video. Decoding such high resolution video generates a large number of memory accesses, so a decoding system needs high-bandwidth for memory system and/or internal communication architecture. In order to determine such requirements, this paper presents an analysis of the memory access complexity for HEVC decoder. we first estimate the amount of memory access performed by software HEVC decoder on an embedded system and a desktop computer. Then, we present the memory bandwidth models for HEVC decoder by analyzing the data flow of HEVC decoding tools. Experimental results show the software decoder produce 6.9-40.5 GB/s of DRAM accesses. also, the analysis reveals the hardware decoder requires 2.4 GB/s of DRAM bandwidth.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.3
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• pp.55-61
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• 2000

This paper presents an efficient hardware architecture of frame memory interface in MPEG-2 video encoder. To reduce the size of memory buffers between SDRAM and the frame memory module, the number of clocks needed for each memory access is minimized with dual bank operation and burst length change. By allocating the remaining cycles not used by SDRAM access, to the random access cycle, the internal buffer size, the data bus width, and the size of the control logic can be minimized. The proposed architecture is operated with 54MHz clock and designed with the VT $I^{тм}$ 0.5 ${\mu}{\textrm}{m}$ CMOS TLM standard cell library. It is verified by comparing the test vectors generated by the c-code model with the simulation results of the synthesized circuit. The buffer area of the proposed architecture is reduced to 40 % of the existing architecture.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10B
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• pp.660-668
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• 2005

Recently, the Internet-based communication method has been adopted as an open networking solution in the field of remote control and data acquisition. In the current Internet, most networking applications are developed according to the client-server approach. In this paper, we propose an innovative Device Configuration Protocol (DCP) that exchanges the traditional role between client and server to provide a uniform device interface over the Internet for various field devices. The proposed protocol is implemented as an application-level protocol running on top of the standard TCP/IP protocols. Also, the DCP protocol is extended with real-time processing to work with the FlowLabel of IPv6 for QoS (Quality of Service) support. The simulation results show that the real-time packets can be processed prior to the given deadline regardless of throughput, as compared to the normal packets.