• Nuclear Engineering and Technology
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• v.40 no.5
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• pp.365-374
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• 2008

Dependability-critical systems, such as digital instrumentation and control systems in nuclear power plants, necessitate engineering techniques and tools to provide assurances of their safety and reliability. Determining system reliability at the architectural design phase is important since it may guide design decisions and provide crucial information for trade-off analysis and estimating system cost. Despite this, reliability and system engineering remain separate disciplines and engineering processes by which the dependability analysis results may not represent the designed system. In this article we provide an overview and application of our approach to build architecture-based, dynamic system models for dependability-critical systems and then automatically generate dynamic fault trees (DFT) for comprehensive, tool-supported reliability analysis. Specifically, we use the Architectural Analysis and Design Language (AADL) to model the structural, behavioral and failure aspects of the system in a composite architecture model. From the AADL model, we seek to derive the DFT(s) and use Galileo's automated reliability analyses to estimate system reliability. This approach alleviates the dependability engineering - systems engineering knowledge expertise gap, integrates the dependability and system engineering design and development processes and enables a more formal, automated and consistent DFT construction. We illustrate this work using an example based on a dynamic digital feed-water control system for a nuclear reactor.

• Journal of the Semiconductor & Display Technology
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• v.14 no.4
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• pp.61-66
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• 2015

With the start of digital broadcasting, TV screen, there is provided a new broadcast service is called EPG (Electronic Program Guide) that can be retrieved directly to a channel or program. However, a study considering the EPG of the user interface on the viewer position is so far insufficient. TV is because everyone watching the media, rather than a specific layer is necessary in order to find easy, intuitive user interface for the program to the viewer. That is, it is possible to quickly find the program to select the attributes that the TV viewer can be easily understood by using the EPG. To this end, this paper first genres which are representative of the properties that distinguish a TV program, time, rating, etc. were systematically classified. So viewers the values of the properties but to specify organized by the EPG, the order of attributes that specify the value we design a user interface that can be selected as having easy. And compare the superiority of the function evaluation of the two through the EPG in the EPG Usability Test proposed by the EPG with the existing commercial paper.

• The KIPS Transactions:PartC
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• v.18C no.4
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• pp.255-264
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• 2011

TV-Anytime is an XML-based standard for description of PVR and digital broadcast services. It is referenced by many standards of digital broadcast service for their schemas and delivery protocols of contents guide. Although its readability and extensibility, TV-Anytime has a big problem which generates massive documents due to its text-based description method. Therefore, various encoding algorithms have been proposed to reduce the size of XML documents. This paper proposes efficient metadata encapsulation architecture based on the optimization information generated at server-side to minimize XML documents. Advanced indexing method is also proposed to reduce resources needed to encapsulate indices and to receive metadata with fast and explicit mechanism.

• Nuclear Engineering and Technology
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• v.49 no.3
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• pp.517-524
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• 2017

Cyber security is an important issue in the field of nuclear engineering because nuclear facilities use digital equipment and digital systems that can lead to serious hazards in the event of an accident. Regulatory agencies worldwide have announced guidelines for cyber security related to nuclear issues, including U.S. NRC Regulatory Guide 5.71. It is important to evaluate cyber security risk in accordance with these regulatory guides. In this study, we propose a cyber security risk evaluation model for nuclear instrumentation and control systems using a Bayesian network and event trees. As it is difficult to perform penetration tests on the systems, the evaluation model can inform research on cyber threats to cyber security systems for nuclear facilities through the use of prior and posterior information and backpropagation calculations. Furthermore, we suggest a methodology for the application of analytical results from the Bayesian network model to an event tree model, which is a probabilistic safety assessment method. The proposed method will provide insight into safety and cyber security risks.

• Journal of Information Technology Services
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• v.21 no.4
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• pp.105-122
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• 2022

NFTs, which guarantee ownership of digital files using blockchain technology, are the new field for the content industry. The NFT provided new opportunities for content creators to trade digital contents without going through mediation freely. Additionally, collectors and investors can safely and easily own their works without the threat of illegal copies. However, since only a limited number of content creators are participating in the NFT market, there needs to be an influx of various content creators and a process of popularization for this market to grow and develop into the main stage. Furthermore, research on NFT has been limited, and understanding the drivers of creators choosing to participate in NFT is insufficient. Thus, this study aims to identify the factors affecting content creators participating in NFT by applying a mixed-methods approach and presenting practical implications. Using topic modeling and in-depth interviews, this study derives the positive and negative factors and suggests strategies to activate content creators' participation in the NFT market. Through this, we can guide that management implication to reduce the risks and costs of participating in NFTs is needed to encourage the participation of creators. It will also provide insight into ways to develop the NFT content market.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.2
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• pp.412-434
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• 2023

This study discusses the high-order diffusion method in the wavelet domain. It aims to improve the edge protection capability of the high-order diffusion method using wavelet coefficients that can reflect image information. During the first step of the proposed diffusion method, the wavelet packet decomposition is a more refined decomposition method that can extract the texture and structure information of the image at different resolution levels. The high-frequency wavelet coefficients are then used to construct the edge detection function. Subsequently, because accurate wavelet coefficients can more accurately reflect the edges and details of the image information, by introducing the idea of state weight, a scheme for recovering wavelet coefficients is proposed. Finally, the edge detection function is constructed by the module of the wavelet coefficients to guide high-order diffusion, the denoised image is obtained. The experimental results showed that the method presented in this study improves the denoising ability of the high-order diffusion model, and the edge protection index (SSIM) outperforms the main methods, including the block matching and 3D collaborative filtering (BM3D) and the deep learning-based image processing methods. For images with rich textural details, the present method improves the clarity of the obtained images and the completeness of the edges, demonstrating its advantages in denoising and edge protection.

• Journal of Korea Society of Digital Industry and Information Management
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• v.19 no.1
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• pp.129-138
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• 2023

The purpose of this study is to explore factors that directly affect the employment of college graduates. To this end, employment data of graduates of private four-year university in Daegu metropolitan area and Gyeongsangbuk-do province were collected from 2019 to 2021, filtered data using a RapidMiner, and analyzed by applying a decision tree model. As a result of the study, long-term internship for more than 12 weeks, TOEIC score of 787.5 or higher was advantageous for employment, and if there was no TOEIC score, the graduation average score was 3.67 or higher, so the possibility of employment was high. Even if the TOEIC score was low, it was advantageous for employment if participating in the contest and continuous professor counseling, and even if the average graduation score was low, the possibility of employment was high if actively participating in the comparison program. This study can present a job education guide based on actual data to university management and use it to establish policies to support employment of college students.

• The Journal of Advanced Prosthodontics
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• v.16 no.1
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• pp.38-47
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• 2024

PURPOSE. This study aims to evaluate the accuracy of different shade selection techniques and determine the matching success of crown restorations fabricated using digital shade selection techniques. MATERIALS AND METHODS. Teeth numbers 11 and 21 were prepared on a typodont model. For the #11 tooth, six different crowns were fabricated with randomly selected colors and set as the target crowns. The following four test groups were established: Group C, where the visual shade selection was performed using the Vita 3D Master Shade Guide and the group served as the control; Group Ph, where the shade selection was performed under the guidance of dental photography; Group S, where the shade selection was performed by measuring the target tooth color using a spectrophotometer; and Group I, where the shade selection was performed by scanning the test specimens and target crowns using an intraoral scanner. Based on the test groups, 24 crowns were fabricated using different shade selection techniques. The ΔE values were calculated according to the CIEDE2000 (2:1:1) formula. The collected data were analyzed by means of a one-way analysis of variance. RESULTS. For the four test groups (Groups C, Ph, S, and I), the following mean ΔE values were obtained: 2.74, 3.62, 2.13, and 3.5, respectively. No significant differences were found among the test groups. CONCLUSION. Although there was no statistically significant difference among the shade selection techniques, Group S had relatively lower ΔE values. Moreover, according to the test results, the spectrophotometer shade selection technique may provide more successful clinical results.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.4
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• pp.316-327
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• 2023

In the case of fully edentulous patients with severe alveolar bone resorption, the consideration of 'All-on-X' implant-supported fixed prosthesis after placing four or more implants in the anterior maxilla is possible. Recent advancements in digital dentistry have enabled systematic and predictable treatment in all phases, including diagnosis, surgery, and prosthesis fabrication. By incorporating digital dentistry techniques such as digital complete denture, implant surgical guides, facial scanning into the conventional restoration process, it is possible to reduce the complexity of the prosthesis fabrication and effectively achieve the transition from provisional prosthesis to definitive prosthesis in terms of both aesthetics and function.

• The Journal of Korean Academy of Prosthodontics
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• v.62 no.2
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• pp.157-164
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• 2024

A variety of digital technologies are being used throughout the entire implant treatment process of diagnosis, surgery, impression, design, and fabrication of prostheses. In this case, using a digital surgical guide, sinus floor elevation was performed without complications, and the implants were placed in the planned position. After the healing period for osseointegration, CAD-CAM (Computer-aided design-Computer-aided manufacturing) customized abutments and provisional prostheses were delivered. While using the provisional prosthesis, occlusal change was observed. To transfer the intermaxillary relationship and abutment position that reflect occlusal change and axial displacement, double scanning and abutment-level digital impressions were taken. Abutment superimposition was used to capture the subgingival margin without gingival retraction. Then, the definitive prosthesis was designed and fabricated with digital system. We report a case applying digital system, to achieve the predictable result as well as the efficient treatment process from implant surgery to fabricating prosthesis in the posterior area.