• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.39
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• pp.87-103
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• 2008

Two kinds of security devices such as independent guarantees and standby letters of credit have been widely used in the international transactions. These devices design to protect one of the parties from a breach by its counter-party. Main uses of these guarantees and standby letters of credit are as follows : bid guarantee, performance guarantee, advance payment guarantee, payment guarantee, retention guarantee, etc. The standby letters of credit were first invented in the U.S.A. and have been widely used in the international and domestic contracts in the U.S.A. But the practical use of these credits is very unsatisfactory in Korea. The purpose of this study is to serve the increase of practical use of the standby letters of credit in Korea through the comparison study on the practical use of the credits between Korea and the U.S.A. Both devices are very similar in function, but they are very different in forms. The one has the form of letter of credits but the other has the form of guarantee. The letter of credit has the stability of governing rule, the legal certainty, and the preference in the field of the trade community comparing to the guarantee. I recommend to use standby letter of credit instead of bank guarantee in international transactions because of the merits of the credit aforesaid.

• Journal of KIISE:Information Networking
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• v.33 no.3
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• pp.218-230
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• 2006

The enterprise service network is composed of internet, intranet and DMZ. The design rationale of Mobile IP is providing of seamless mobility transparency without regarding to the type of network topology and services. However, Mobile IP specification does not include the mobility support in case of using VPN environment and define the access scenarios to get into the VPN intranet without disturbing existing security policy. In this paper, we propose an authentication method using AAA infrastructure and keying material exchange to enable an user in internet to be able to access the intranet through the VPN gateway. Finally, performance analysis for the proposed scheme is provided.

• Fashion & Textile Research Journal
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• v.6 no.1
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• pp.93-101
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• 2004

The purpose of this study is to examine consumers' risk perception in internet clothing shopping and its relation with technology readiness and the frequency of purchase. Thereafter, this study examines how consumers' risk perception affect service quality and satisfaction at the apparel shopping sites. An on-line survey was made to collect data, and the replies from 785 people, who had an experience of apparel shopping on line, were used in data analysis. From factor analyses, risk perception comprised 3 factors of product related risk, delivery related risk, and security related risk, and technology readiness comprised 4 factors of optimism, innovativeness, discomfort, and insecurity. Based on cluster analysis, consumers were classified into 3 types in terms of the internet risk perception: low risk group, medium risk group, and high risk group. From path analysis, risk perception was decreased with high frequency of purchase and low discomfort and insecurity of technology readiness, and risk perception and service quality had an influence on consumers' satisfaction with the shopping sites.

• Journal of the Korea society of information convergence
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• v.5 no.2
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• pp.67-76
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• 2012

XML-based open protocol, XMPP users to pass messages to other users, which means that a decentralized communication network is the network infrastructure and enable it. In addition, XMPP servers using a professional server-to-server protocol to communicate with each other and decentralized social networks and collaboration framework provides an important possibility. In this paper, the features of XMPP messaging protocol is applicable to automotive telematics terminals XMPP-based platform design, and presence of two-way communication point for the problem, point-to-point session setup issues, security issues, compatibility issues, and to solve the scalability problem XMPP-based messaging system was implemented.

• ETRI Journal
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• v.35 no.3
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• pp.448-458
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• 2013

This paper presents a generalized post-processing technique for enhancing the pseudorandomness of digital chaotic oscillators through a nonlinear XOR-based operation with rotation and feedback. The technique allows full utilization of the chaotic output as pseudorandom number generators and improves throughput without a significant area penalty. Digital design of a third-order chaotic system with maximum function nonlinearity is presented with verified chaotic dynamics. The proposed post-processing technique eliminates statistical degradation in all output bits, thus maximizing throughput compared to other processing techniques. Furthermore, the technique is applied to several fully digital chaotic oscillators with performance surpassing previously reported systems in the literature. The enhancement in the randomness is further examined in a simple image encryption application resulting in a better security performance. The system is verified through experiment on a Xilinx Virtex 4 FPGA with throughput up to 15.44 Gbit/s and logic utilization less than 0.84% for 32-bit implementations.

• ETRI Journal
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• v.42 no.4
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• pp.619-632
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• 2020

Highly dispersive S-boxes are desirable in cryptosystems as nonlinear confusion sublayers for resisting modern attacks. For a near optimal cryptosystem resistant to modern cryptanalysis, a highly nonlinear and low differential probability (DP) value is required. We propose a method based on a piecewise linear chaotic map (PWLCM) with optimization conditions. Thus, the linear propagation of information in a cryptosystem appearing as a high DP during differential cryptanalysis of an S-box is minimized. While mapping from the chaotic trajectory to integer domain, a randomness test is performed that justifies the nonlinear behavior of the highly dispersive and nonlinear chaotic S-box. The proposed scheme is vetted using well-established cryptographic performance criteria. The proposed S-box meets the cryptographic performance criteria and further minimizes the differential propagation justified by the low DP value. The suitability of the proposed S-box is also tested using an image encryption algorithm. Results show that the proposed S-box as a confusion component entails a high level of security and improves resistance against all known attacks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.8
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• pp.3701-3727
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• 2016

Recently Service Function Chaining (SFC) is promising to innovate the network service mode in modern networks. However, a feasible implementation of SFC is still difficult due to the need to achieve functional equivalence with traditional modes without sacrificing performance or increasing network complexity. In this paper, we present a configurable network service chaining (CNSC) mechanism to provide services for network traffics in a flexible and optimal way. Firstly, we formulate the problem of network service chaining and design an effective service chain construction framework based on integrating software-defined networking (SDN) with network functions virtualization (NFV). Then, we model the service path computation problem as an integer liner optimization problem and propose an algorithm named SPCM to cooperatively combine service function instances with a network utility maximum policy. In the procedure of SPCM, we achieve the service node mapping by defining a service capacity matrix for substrate nodes, and work out the optimal link mapping policies with segment routing. Finally, the simulation results indicate that the average request acceptance ratio and resources utilization ratio can reach above 85% and 75% by our SPCM algorithm, respectively. Upon the prototype system, it is demonstrated that CNSC outperforms other approaches and can provide flexible and scalable network services.

• Journal of Sasang Constitutional Medicine
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• v.29 no.3
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• pp.224-231
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• 2017

Objectives Several researches have been done to develop instruments or questionnaire for diagnosis of sasang constitution. In this study, we developed a user-friendly web system to enhance the utilization of KS-15. Methods The KS-15 Web application was constructed by considering the responsive web design and easy survey answer. This system is designed only to authorized users for security purposes, and provides two modes, simple mode and expert mode, depending on the purpose of using the system. A simple mode do not keep user information and survey answer in the database. An expert mode support management of patients, diagnosis of sasang constitution and statistical functions. Results & Conclusions The developed KS-15 system can be operated from any smart device's web browser. In order to use information in clinic field, it was developed so that it can be accessed only by authorized users. It can be divided into an account which can use only simple mode and an account which can use expert mode by using a difference in access authority. These functions can enhance the applicability of sasang constitution in real life such as clinical or education.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.2
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• pp.811-829
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• 2015

One-way authenticated key agreement protocols, aiming at solving the problems to establish secure communications over public insecure networks, can achieve one-way authentication of communicating entities for giving a specific user strong anonymity and confidentiality of transmitted data. Public Key Infrastructure can design one-way authenticated key agreement protocols, but it will consume a large amount of computation. Because one-way authenticated key agreement protocols mainly concern on authentication and key agreement, we adopt multi-server architecture to realize these goals. About multi-server architecture, which allow the user to register at the registration center (RC) once and can access all the permitted services provided by the eligible servers. The combination of above-mentioned ideas can lead to a high-practical scheme in the universal client/server architecture. Based on these motivations, the paper firstly proposed a new one-way authenticated key agreement scheme based on multi-server architecture. Compared with the related literatures recently, our proposed scheme can not only own high efficiency and unique functionality, but is also robust to various attacks and achieves perfect forward secrecy. Finally, we give the security proof and the efficiency analysis of our proposed scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1329-1340
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• 2016

Recently, Zhang proposed a scheme to hide information in encrypted images using synchronous stream ciphers. After the receiver decrypts the encrypted image and extracts data by calculating the spatial correlation property value using the fluctuation function which is designed to calculate spacial correlation between adjacent pixels in a decrypted image. Then, Hong improved the Zhang's data hiding scheme by introducing the side match technique. In this paper, a novel fluctuation function is proposed to reduce the recovery errors which arise during extracting hidden data. Then, we also demonstrated that the proposed fluctuation function outperforms the previous functions through computer simulations for sample images.