• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.4
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• pp.73-78
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• 2018

In this paper, we consider a system where multiple sources are encrypted in separated nodes and sent through their respective public communication channels into a joint sink node. We are interested at the problem on protecting the security of an already existing system such above, which is found out to have correlated encryption keys. In particular, we focus on finding a solution without introducing additional secret keys and with minimal modification to minimize the cost and the risk of bringing down an already running system. We propose a solution under a security model where an eavesdropper obtains all ciphertexts, i.e., encrypted sources, by accessing available public communication channels. Our main technique is to use encoders of universal function to encode the ciphertexts before sending them to public communication channels.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1388-1397
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• 2015

Recently, an application business model was proposed to implement an M-coupon system using the NFC-based mobile devices. In this paper, the security requirements were surveyed for a secure M-coupon system and to analyze the threats on the existing NFC-based M-coupon protocols. After considering the implementation efficiency and security, this paper presents a novel M-coupon protocol based on the Diffie-Hellman key agreement scheme. This protocol can be an alternative to solve the security problems related to the PKI (Public Key Infrastructure) and secret key distribution. Furthermore, this M-coupon protocol is designed to provide user authentication and counteract the relay attack.

• Parasites, Hosts and Diseases
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• v.53 no.4
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• pp.493-496
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• 2015

Toxoplasmosis, caused by Toxoplasma gondii, is a parasitic zoonosis with worldwide distribution. The present study investigated the prevalence of T. gondii in dogs in Zhanjiang city, southern China, using both serological and molecular detection. A total of 364 serum samples and 432 liver tissue samples were collected from the slaughter house between December 2012 and January 2013 and were examined for T. gondii IgG antibody by ELISA and T. gondii DNA by semi-nested PCR based on B1 gene, respectively. The overall seroprevalence of T. gondii IgG antibody was 51.9%, and T. gondii DNA was detected in 37 of 432 (8.6%) liver tissue samples. These positive DNA samples were analyzed by PCR-RFLP at 3'- and 5'-SAG2. Only 8 samples gave the PCR-RFLP data, and they were all classified as type I, which may suggest that the T. gondii isolates from dogs in Zhanjiang city may represent type I or type I variant. This study revealed the high prevalence of T. gondii infection in dogs in Zhanjiang city, southern China. Integrated measures should be taken to prevent and control toxoplasmosis in dogs in this area for public health concern.

• Journal of Internet Computing and Services
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• v.23 no.3
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• pp.21-33
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• 2022

This paper is to suggest the secure secret sharing system in order to outstandingly reduce the damage caused by the leakage of the corporate secret. This research system is suggested as efficient P2P distributed system kept from the centrally controlled server scheme. Even the bitcoin circulation system is also based on P2P distribution scheme recenly. This research has designed the secure circulation of the secret shares produced by Threshold Shamir Secret Sharing scheme instead of the shares specified in the torrent file using the simple, highly scalable and fast transferring torrent P2P distribution structure and its protocol. In addition, this research has studied to apply both Shamir Threshold Secret Sharing scheme and the securely strong multiple user authentication based on Collaborative Threshold Autentication scheme. The secure transmission of secret data is protected as using the efficient symmetric encryption with the session secret key which is safely exchanged by the public key encryption. Also it is safer against the leakage because the secret key is effectively alive only for short lifetime like a session. Especially the characteristics of this proposed system is effectively to apply the threshold secret sharing scheme into efficient torrent P2P distributed system without modifying its architecture of the torrent system. In addition, this system guaranttes the confidentiality in distributing the secret file using the efficient symmetric encryption scheme, which the session key is securely exchanged using the public key encryption scheme. In this system, the devices to be taken out can be dynamically registered as an user. This scalability allows to apply the confidentiality and the authentication even to dynamically registerred users.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2001.11a
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• pp.318-321
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• 2001

We have designed an Internet voting system applicable for worldwide voting which is based on Ohkubo et. al,'s scheme[9] combined with Public Key Infrastructure (PKI). To the best of our knowledge, this is the first trial to serve secure Internet voting system to the world. In our system, voter's privacy is guaranteed by using blind signature and mix-net, and robustness is provided through the threshold encryption scheme. By employing Java technology, we propose a way of typical implementation for internet voting system. Furthermore, PKI permits worldwide key distribution and achieve “one certificate/one vote” policy. Therefore, anyone can participate in the voting if he gets a certificate from Certificate Authority (CA). By the joint work between Korean and Japanese teams, the implementation aims to select MVPs in 2002 FIFA World Cup Korea-Japan$\^$TM/ in easy and friendly manner for any Internet user to participate and enjoy Internet voting.

• The Journal of Asian Finance, Economics and Business
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• v.5 no.3
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• pp.185-193
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• 2018

This paper aims to explore the risk governance framework and socially viable solutions, attempting to provide guidance for the decision making process. The key idea of this study start with overcoming the limitations of IRGC risk governance framework, which mainly focuses on a comprehensive framework for risk governance. This article has employed SWOT analysis as a methodology, which is a strategic planning technique used to help identifying the strengths, weaknesses, opportunities, and threats related to business competition or risk management. In this paper, socially viable solutions as an alternative plan place emphasis on the adoption of concern assessment through a concerns table. It is also proposed that scoping has to get introduced, with SWOT analysis in the process. The results of this paper support that multiple stakeholders have to participate in the process of identifying and framing risk and communicating with each other, considering the context. It should be noted that communities can become involved and take important parts in decision making process in various ways. It is recommended that engaging stakeholders to both risk assessment and risk management is material to dealing with risk in a socially viable way. It also implies that the community-based disaster management should be better prepared for the decision making process in socially viable solutions.

• The Journal of Industrial Distribution & Business
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• v.11 no.6
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• pp.7-17
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• 2020

Purpose: The purpose of this study is to examine the factors affecting the academic achievement of international students in degree programs in global education environment. Based on exploratory research, this study proposed four factors and examined effects of academic factors on academic satisfaction, effects of social factors on social adjustment, effects of cultural factors on cultural adaption, effects of economic factors on financial stability, and effects of four factors on academic achievement of international students. Research design, data, and methodology: This study conducted online survey to collect the data and results provide importance to increase interactivity between international students and teachers and between international students and hosting country's students. Results: The results of this study found what variables affect four proposed factors, while academic satisfaction significantly affects academic achievement rather than other factors. Conclusions: The results show how to improve academic related variables is key for the success of academic achievement. Results of this study provide implications which aspects should be considered to increase overall academic achievement by managing and improving the quality of higher education in global setting. This study provides managerial and policy implications for enhanced academic achievement of international students in global context.

• The Journal of Fisheries Business Administration
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• v.35 no.1
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• pp.117-132
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• 2004

This study attempts to suggest a new approach of the estimation of range and degree of fisheries damages caused by a large scale of reclamation undertaken in coastal area using the central limit theorem(CLT) in statistics. The key result of the study is the introduction of the new concept of critical variation of environmental factor($d_{c}$). The study defines $d_{c}$ as a standard deviation of the sample mean($\bar{X}$) of environmental factor(X), in other words, $\frac{\sigma}{ \sqrt{n}}$. The inner bound of $d_{c}$ could be the area of fisheries damages caused by public coastal undertaking. The study also defines the decreasing rate of fisheries production$\delta_{\varepsilon}$, in other words, degree of fisheries damages, as the rate of change in the distribution of sample mean(($\bar{X}$), caused by the continuous and constant variation of environmental factor. Therefore $\delta_{\varepsilon}$ can be easily calculated by the use of table of the standardized normal distribution.

• Journal of Digital Convergence
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• v.12 no.10
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• pp.253-258
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• 2014

Recently, the development of cloud computing technology is developed as soon as smartphones is increases, and increased that users want to receive big data service. Hadoop framework of the big data service is provided to hadoop file system and hadoop mapreduce supported by data-intensive distributed applications. But, smpartphone service using hadoop system is a very vulnerable state to data authentication. In this paper, we propose a initial authentication protocol of hadoop system assisted by smartphone service. Proposed protocol is combine symmetric key cryptography techniques with ECC algorithm in order to support the secure multiple data processing systems. In particular, the proposed protocol to access the system by the user Hadoop when processing data, the initial authentication key and the symmetric key instead of the elliptic curve by using the public key-based security is improved.

• Journal of Web Engineering
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• v.21 no.5
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• pp.1377-1418
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• 2022

As it has been recently proven that the public key-based RSA algorithms that are currently used in encryption can be unlocked by Shor's algorithm of quantum computers in a short time, conventional security systems are facing new threats, and accordingly, studies have been actively conducted on new security systems. They are classified into two typical methods: Post Quantum Cryptography (PQC) and Quantum Key Distribution (QKD). PQC aims to design conventional cryptography systems in a more robust way so that they will not be decrypted by a quantum computer in a short time whereas QKD aims to make data tapping and interception physically impossible by using quantum mechanical characteristics. In this paper, we design a quantum key management system, which is most crucial for constructing a QKD network and analyze the design requirements to apply them to Korea Research Environment Open NETwork (KREONET). The quantum key management system not only manages the lifecycle, such as storage, management, derivation, allocation, and deletion of the symmetric key generated in QKD but also enables many-to-many communication in QKD communication based on the key relay function and P2P communication to overcome the limitation of distance, which is a disadvantage of QKD. We have validated the designed quantum key management system through simulations to supplement the parts that were not considered during the initial design.