• ETRI Journal
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• v.33 no.4
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• pp.621-628
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• 2011

The redactable signature scheme was introduced by Johnson and others in 2002 as a mechanism to support disclosing verifiable subdocuments of a signed document. In their paper, a redactable signature based on RSA was presented. In 2009, Nojima and others presented a redactable signature scheme based on RSA. Both schemes are very efficient in terms of storage. However, the schemes need mechanisms to share random prime numbers, which causes huge time consuming computation. Moreover, the public key in the scheme of Johnson and others is designed to be used only once. In this paper, we improve the computational efficiency of these schemes by eliminating the use of a random prime sharing mechanism while sustaining the storage efficiency of them. The size of our signature scheme is the same as that of the standard RSA signature scheme plus the size of the security parameter. In our scheme, the public key can be used multiple times, and more efficient key management than the scheme of Johnson and others is possible. We also prove that the security of our scheme is reduced to the security of the full domain RSA signature scheme.

• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1060-1068
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• 2018

Droop control schemes have been widely employed in the control strategies for Multi-Terminal Direct Current (MTDC) system for its high reliability. Under the conventional DC voltage-active power droop control, the droop slope applies a proportional relationship between DC voltage error and active power error for power sharing. Due to the existence of DC network impedance and renewable resource fluctuation, there is inevitably a DC voltage deviation from the droop characteristic, which in turn results in inaccurate control of converter's power. To tackle this issue, a piecewise droop control with DC voltage dead band or active power dead band is implemented into controller design. Besides, an advanced droop control scheme with versatile function is proposed, which enables the converter to regulate DC voltage and AC voltage, control active and reactive power, get participated into frequency control, and feed passive network. The effectiveness of the proposed control method has been verified by simulation results.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.14-20
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• 2013

Substantial research has been performed on the data standards and exchanges in the AEC/FM industry over the past several years. The growing popularity of BIM technology is based heavily upon a perception that the technology can facilitate the sharing and reuse of information during a project life-cycle. Although many researchers and practitioners are in agreement about the potential applicability and benefit of BIM in construction, it is still unclear why BIM is adopted, and what factors enhance implementation of BIM. Thus, BIM acceptance and use remains a central concern of BIM research and practice. Therefore, we propose the key factors affecting the acceptance of BIM in construction organizations using factor analysis. The key factors for BIM acceptance are identified through a literature review in TAM (Davis 1989) and related theories, and consolidated by interviews and pilot studies with professionals in construction industry. Based on the factors, a questionnaire was designed and sent out to construction organizations such as contractors, architects, and engineers in Korea. Total 148 completed questionnaires were retrieved. Using factor analysis, key factors were grouped into six dimensions. These findings will clarify what the highly prioritized factors are, and can also be used in an assessment tool for the performance of BIM utilization.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.3
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• pp.1-6
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• 2015

The IoT(Internet of things) technology enable objects around user to be connected with each other for sharing information. To support security is the mandatory requirement in IoT because it is related to the disclosure of private information but also directly related to the human safety. However, it is difficult to apply traditional security mechanism into lightweight devices. This is owing to the fact that many IoT devices are generally resource constrained and powered by battery. PSK(Pre-Shared Key) based approach, which share secret key in advance between communication entities thereafter operate security functions, is suitable for light-weight device. That is because PSK is costly efficient than a session key establishment approach based on public key algorithm. However, how to safely set a PSK of the lightweight device in advance is a difficult issue because input/output interfaces such as keyboard or display are constrained in general lightweight devices. To solve the problem, we propose and develop a secure PSK configuration scheme for resource constrained devices in IoT.

• The Journal of Information Systems
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• v.17 no.2
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• pp.1-26
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• 2008

SCM is one of the important key issues in Internet-based business environment. This study intends to suggest a research model to measure the influence of environmental, organizational, information technology factors on organizational performance using the four perspectives of balanced scorecard (BSC). 9 independent variables and 4 dependent variables were adopted from existing literature review. 103 companies data were collected by survey. Four hypotheses in this study were generated to analyze the positive relationship of environmental, organizational, information systems on organizational performance with 4 perspectives of BSC. The results of hypothesis testing show as follows. First, organizational performance of learning and growth perspective has a positive influence of IS maturity, process innovation, top management support, use of SCM package, IS interoperability, and objectives sharing. Second organizational performance of infernal process perspective has a positive influence of process innovation, IS interoperability, objectives sharing, top management support, use of SCM package, competitiveness, and IS maturity. Third, organizational performance of customer perspective has a positive influence of IS interoperability, objectives sharing, process innovation, IS maturity, competitiveness, and use of SCM package. Finally, organizational performance of financial perspective has a positive influence of process in innovation, use of SCM package, IS maturity, objectives sharing, IS interoperability, and top management support. The contribution of this study is that it provides a conceptual framework and empirical evidences of the causal relationship between environmental, organizational, IS factor and organizational performance with 4 perspectives of BSC.

• Journal of the Economic Geographical Society of Korea
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• v.15 no.4
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• pp.515-533
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• 2012

Industrial cluster is adopted as a key policy for the development of regional and national economies in many developed or under-developing countries. The industrial cluster is basically concerned with knowledge sharing and exchanges among diverse functions such as firms, research institutions, and universities in a regional or innovation-network context. Therefore, activities to promote knowledge sharing and exchanges in an industrial cluster become very important activities to reach to the original purpose of an industrial cluster. In this study, factors affecting performance of those activities to promote knowledge sharing and exchanges in an industrial cluster are defined and the effects are examined through empirical study. For this research, surveys on enterprisers and employees in industrial cluster were conducted and statistical analysis methods such as correlation analysis, multiple regression analysis, and canonical correlation analysis were adopted for analyses.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.430-432
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• 2022

With the recent increase in interest in the open science movement in science and technology fields such as open access, open data, and open source, the movement to share and utilize publicly funded research products is materializing and revitalizing. In line with this trend, many efforts are being made to establish and revitalize a system for sharing and utilizing research data, which is a key resource for research in Korea. These efforts are mainly focused on collecting research data by field and institution, and linking it with DataON, a national research data platform, to search and utilize it. However, developed countries are building a system that can share and utilize not only such research data but also various types of R&D-related computing resources such as IaaS, PaaS, SaaS, and MLaaS. EOSC (European Open Science Cloud), ARDC (Australian Research Data Commons), and CSTCloud (China S&T Cloud) are representative examples. In Korea, the Korea Research Data Commons (KRDC) is designed and a core framework is being developed to facilitate the sharing of these computing resources. In this study, the necessity, concept, composition, and future plans of KRDC are introduced.

• Journal of Digital Convergence
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• v.18 no.12
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• pp.231-242
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• 2020

Due to fierce market competition and COVID-19, it becomes increasingly important for sharing economic platform companies to develop a long-term relationship with customers. In this regard, this study explores the mechanism of customer's repurchase decision making in the context of Airbnb. This study posits customer satisfaction and brand image as the key factors in forming customer's repurchase intention toward Airbnb. It also investigates the effects of price fairness, authentic experience, enjoyment, Airbnb trust and host trust on customer's repurchase intention. This study validated the research hypothesis with 154 customers using Airbnb. The analysis results showed that both customer satisfaction and brand image have a significant impact on repurchase intention and explain 62.0% of its variance. Enjoyment, true experience, and Airbnb trust had significant effects on customer satisfaction, while price fairness and host trust had no significant impact on it. The results revealed that price fairness, authentic experience, enjoyment, and Airbnb trust are significantly associated with brand image, while host trust is not significantly related to it. The results of this study are expected to provide academic and practical implications by enhancing the understanding of customer's repurchasing decision in the context of sharing economic platform.

• Journal of The Korean Association For Science Education
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• v.43 no.2
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• pp.125-137
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• 2023

This study analyzed the types of knowledge building discourse and knowledge building processes in small group learning using augmented reality. Eight 8th grade students took classes using augmented reality in solubility, boiling and melting points. These classes were carried out twice and all the classes were videotaped and recorded. Every student participated in a semi-structured interview. In the types of knowledge building discourse, the proportion of knowledge sharing and knowledge construction was similar. Beneath the knowledge sharing, the proportion of introductory level discussion was higher than identifying key elements of augmented reality. Recalling existing knowledge rarely appeared. Under the knowledge construction, the proportion of advanced level discussion was the highest and the proportion of sharing and critiquing ideas at a different level and efforts to rise above current levels of explanation was similar. The introductory level discussion and identifying key elements of augmented reality were developed into efforts to rise above current levels of explanation and sharing and critiquing ideas at a different level. Visualized results of knowledge building processes showed all the students' graph drew an upward curve, though cumulative number of impact value was different by each student. As a result of the study, effective ways of improving small group learning using augmented reality are discussed.

• The KIPS Transactions:PartC
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• v.12C no.7 s.103
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• pp.949-958
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• 2005

In the paper we study key agreement schemes when a party needs to establish a session key with each of several parties, thus having multiple session keys. This situation can be represented by a graph, tailed a key graph, where a vertex represents a party and an edge represents a relation between two parties sharing a session key. graphs to establish all session keys corresponding to all edges in a key graph simultaneously in a single session. A key agreement protocol of a key graph is a natural extension of a two-party key agreement protocol. We propose a new key exchange model for key graphs which is an extension of a two-party key exchange model. using the so-called randomness re-use technique which re-uses random values to make session keys for different sessions, we suggest two efficient key agreement protocols for key graphs based on the decisional Diffie-Hellman assumption, and prove their securities in the key exchange model of key graphs. Our first scheme requires only a single round and provides key independence. Our second scheme requires two rounds and provides forward secrecy. Both are proven secure In the standard model. The suggested protocols are the first pairwise key agreement protocols and more efficient than a simple scheme which uses a two-party key exchange for each necessary key. Suppose that a user makes a session key with n other users, respectively. The simple scheme's computational cost and the length of the transmitted messages are increased by a factor of n. The suggested protocols's computational cost also depends on n, but the length of the transmitted messages are constant.