• Nuclear Engineering and Technology
• /
• v.51 no.3
• /
• pp.692-701
• /
• 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

• Journal of Information Technology Services
• /
• v.8 no.4
• /
• pp.103-113
• /
• 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.

• Proceedings of the KIEE Conference
• /
• 2006.10c
• /
• pp.576-578
• /
• 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.

• Journal of the Korean Society of Costume
• /
• v.61 no.5
• /
• pp.48-63
• /
• 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.

• Journal of Korean Library and Information Science Society
• /
• v.35 no.3
• /
• pp.119-138
• /
• 2004

The objective of digital preservation is to ensure that digital information survives in usable form for as long as it is wanted That is to ensure long-term access to digitally stored information. The preservation of digital objects involves a variety of challenges, including policy questions, institutional roles, legal and rights issues, metadata, and technical strategies. In this paper, I introduce the definition of digital object life-cycle of digital object and related archiving workflow which are basic concepts of digital archiving. Also I focus on the aspects of current techniques used in digital information preservation including technology preservation, emulation, refreshing, migration, encapsulation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2006.05a
• /
• pp.721-724
• /
• 2006

This paper presents a method of the constructing the digital logic switching functions and realizing the circuit design using partition techniques. First of all, we introduce the necessity, background and concepts of the partition design techniques for the digital logic systems. Next, we discuss the definitions that are used in this paper. For the purpose of the circuit design for the digital logic switching functions, we discuss the extraction of the partition functions. Also we describe the construction method of the building block, that is called the building block, based on each partition functions. And we apply the proposed method to the example, and we compare the results with the results of the earlier methods. In result, we describe the control functions, it means that we obtain the effective cost in the digital logic design for any other earlier methods.

• Journal of Communications and Networks
• /
• v.11 no.2
• /
• pp.196-206
• /
• 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.

• Journal of the Institute of Convergence Signal Processing
• /
• v.12 no.3
• /
• pp.176-180
• /
• 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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2001.05a
• /
• pp.629-632
• /
• 2001

In this paper, We compared with advantage and disadvantage about several wavelet-basis watermarking techniques for digital image. Watermarking is embedding a digital signal called as 'watermark' into images to claim the ownership. In this study, simulation performed using wavelet based method among the various watermarking techniques proposed on domestic and foreign country. The experimental results show that the efficiency watermarking techniques among the proposed various techniques with good quality and robustness property.

• Nuclear Engineering and Technology
• /
• v.44 no.4
• /
• pp.421-428
• /
• 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.