• Nuclear Engineering and Technology
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• 제51권3호
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• pp.692-701
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• 2019

Recently, instrumentation and control (I&C) systems in nuclear power plants have undergone digitalization. Owing to the unique characteristics of digital I&C systems, the reliability analysis of digital systems has become an important element of probabilistic safety assessment (PSA). In a reliability analysis of digital systems, fault-tolerant techniques and their effectiveness must be considered. A fault injection experiment was performed on a safety-critical digital I&C system developed for nuclear power plants to evaluate the effectiveness of fault-tolerant techniques implemented in the target system. A software-implemented fault injection in which faults were injected into the memory area was used based on the assumption that all faults in the target system will be reflected in the faults in the memory. To reduce the number of required fault injection experiments, the memory assigned to the target software was analyzed. In addition, to observe the effect of the fault detection coverage of fault-tolerant techniques, a PSA model was developed. The analysis of the experimental result also can be used to identify weak points of fault-tolerant techniques for capability improvement of fault-tolerant techniques

• 한국IT서비스학회지
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• 제8권4호
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• pp.103-113
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• 2009

The industry of cultural digital contents has been regarded as the main next generation industry. Recently techniques for restoring cultural assets and the multiple usage of those have been developed in our country. Using computer graphics and image processing techniques, many cultural assets have been restored. If the focus for researches and supports to cultural assets restoration grows rapidly, we will create cultural and economical added-values and get the benefit of that technology. In this paper, we introduce the techniques for restoring cultural assets focused on computer graphics and image processing techniques.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
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• pp.576-578
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• 2006

The wide use of digital media during the past few years, has led to an increase of digital piracy and tampering. To deal with these problems, the concept of digital fingerprinting has been introduced. Digital fingerprinting is an effective method to identify users who might try to redistribute multimedia content. In this paper, we propose new digital image fingerprinting techniques using watermark shifting scheme and concept of domain.

• 복식
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• 제61권5호
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• pp.48-63
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• 2011

Digital makeup(DM), depending upon computer graphic softwares, is applied to various fields, e.g. character works in movie and game industries and visual printouts in printing works. Focused on makeup field, DM is extremely conducive to developing, scientizing and informationalizing makeup patterns. Despite of unlimited potential of DM of which market size has been growing day by day, its practical use by domestic makeup experts and educators is much less active than expected as far, due to the lack of knowledge accumulation. The purpose of this study is to suggest some theoretical frameworks to generalize DM techniques and analyze two cases using the frames therefore support academicians' recent efforts to theorize DM techniques. The study 1) defines and categorizes the concepts of DM and DFX(digital special effect); 2) reviews the literature relevant to DM and generalizes the types and methods of DM techniques; 3) applies general frames to analyzing two movie cases, famous for their DM effects; 4) then suggests, based upon analytical results, some efficient ways for makeup experts to use DM techniques in practice. This study contributes to providing the theoretical grounds to conceptualize DM thus broadening makeup artists' interests in DM and awakening the scholarly concerns in cultural technology including DM.

• 한국도서관정보학회지
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• 제35권3호
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• pp.119-138
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• 2004

디지털보존은 디지털정보를 장기적으로 보유하여 이용자로 하여금 지속적으로 접근이 가능하도록 하는 일련의 행위를 말한다. 이를 위해서는 기술적인 문제를 포함하여 정책적인 문제, 기관의 역할, 법적 및 저작권 문제, 메타데이터 전략 등 여러 가지 복잡한 세부 과제들을 해결하여야 한다. 본 논문은 이 중에서 디지털보존과 관련된 기술적인 문제를 2가지로 구분하여 정리하고 있다. 먼저, 디지털보존의 기본적인 개념을 형성하는 요소인 디지털객체, 디지털객체의 수명주기, 아카이빙 워크플로우를 시스템의 입장에서 정의하였다. 둘째, 기술보존, 에물레이션, 파일재생, 포맷전환, 캡슐화 등 디지털보존에 사용되는 주요한 보존처리 기술을 비교 분석하였다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2006년도 춘계종합학술대회
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• pp.721-724
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• 2006

본 논문에서는 분할기법을 이용하여 디지털논리스위칭함수를 구성하는 한가지 방법을 제안하였다. 먼저, 디지털논리시스템에 대한 분할기법의 개념을 서술하였고, 본 논문에서 사용되는 각종 정의에 대해 논의하였다. 또한, 제안한 방법으로 구한 디지털논리스위칭함수를 회로설계하기 위해 먼저, 각각의 분할함수에 기초를 둔 Building Block(BB)을 구성에 대해 서술하였다. 그리고 이들 BB를 근간으로 회로설계하는 방법에 대해 논의하였다. 그리고 제안한 방법을 적용 예를 들어 그 결과를 기존의 방법과 비교 및 검토하였다. 그 결과 기존의 방법에 비해 효과적인 cost를 얻을 수 있었다.

• Journal of Communications and Networks
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• 제11권2호
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• pp.196-206
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• 2009

Over the last five years, relaying or multihop techniques have been intensively researched as means for potentially improving link performance of wireless networks. However, the data rates of relays are often limited because they cannot transmit and receive on the same frequency simultaneously. This limitation has come to the attention of researchers, and recently a number of relay techniques have been proposed specifically to improve the data efficiency of relaying protocols. This paper surveys transmission protocols that employ first single relays, then multiple relays and finally multiple antenna relays. A common feature of these techniques is that novel signal processing techniques are required in the relay network to support increased data rates. This paper presents results and discussion that highlight the advantages of these approaches.

• 융합신호처리학회논문지
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• 제12권3호
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• pp.176-180
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• 2011

Even though algorithms for watermark embedding and extraction step are important issue for digital watermarking, watermark selection and post-processing can give us an opportunity to improve our algorithms and achieve higher performance. For this reason, we summarized the possibilities of improvements for digital watermarking by referring to the watermark merging techniques rather than embedding and extraction algorithms in this paper. We chose Cox's function as main embedding and extraction algorithm, and multiple barcode watermarks as a watermark. Each bit of the multiple copies of barcode watermark was embedded into a gray-scale image with Cox's embedding function. After extracting the numbers of watermark, we applied the watermark merging techniques; including the simple merging, N-step iterated merging, recover merging and combination of iterated-recover merging. Main consequence of our paper was the fact of finding out how multiple barcode watermarks and merging techniques can give us opportunities to improve the performance of algorithm.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 춘계종합학술대회
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• pp.629-632
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• 2001

본 논문은 최근 급격히 대두되어지고 있는 디지털 영상에 대한 워터마킹(Watermarking) 기법들중에서 웨이블릿 기반의 여러 가지 기법들에 대한 장/단점을 비교하였다. 워터마킹은 소유권을 주장하기 위하여 '워터마크'라는 디지털 신호를 영상에 첨가하는 것이다. 본 연구에서는 다양한 워터마킹 기법들 중에서 웨이블릿 기법을 이용한 워터마킹에 대해서 국 내/외에서 주장되어진 여러 가지 예들을 가지고 비교함으로써, 보다 실용적인 워터마킹 기법을 제시하고자 한다. 실험 결과 제안된 여러 가지 기법들 중에서 보다 우수한 화질과 강인한 특성을 가지는 워터마킹 기법에 대해서 알 수 있었다.

• Nuclear Engineering and Technology
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• 제44권4호
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• pp.421-428
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• 2012

Analog instrument and control systems in nuclear power plants have recently been replaced with digital systems for safer and more efficient operation. Digital instrument and control systems have adopted various fault-tolerant techniques that help the system correctly and safely perform the specific required functions regardless of the presence of faults. Each fault-tolerant technique has a different inspection period, from real-time monitoring to monthly testing. The range covered by each faulttolerant technique is also different. The digital instrument and control system, therefore, adopts multiple barriers consisting of various fault-tolerant techniques to increase the total fault detection coverage. Even though these fault-tolerant techniques are adopted to ensure and improve the safety of a system, their effects on the system safety have not yet been properly considered in most probabilistic safety analysis models. Therefore, it is necessary to develop an evaluation method that can describe these features of digital instrument and control systems. Several issues must be considered in the fault coverage estimation of a digital instrument and control system, and two of these are addressed in this work. The first is to quantify the fault coverage of each fault-tolerant technique implemented in the system, and the second is to exclude the duplicated effect of fault-tolerant techniques implemented simultaneously at each level of the system's hierarchy, as a fault occurring in a system might be detected by one or more fault-tolerant techniques. For this work, a fault injection experiment was used to obtain the exact relations between faults and multiple barriers of faulttolerant techniques. This experiment was applied to a bistable processor of a reactor protection system.