• Journal of the Korea Society of Computer and Information
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• v.22 no.8
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• pp.55-61
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• 2017

Cloud computing is cost-effective in terms of system configuration and maintenance and does not require special IT skills for management. Also, cloud computing provides an access control setting where SSO is adopted to secure user convenience and availability. As the SSO user authentication structure of cloud computing is exposed to quite a few external security threats in wire/wireless network integrated service environment, researchers explore technologies drawing on distributed SSO agents. Yet, although the cloud computing access control using the distributed SSO agents enhances security, it impacts on the availability of services. That is, if any single agent responsible for providing the authentication information fails to offer normal services, the cloud computing services become unavailable. To rectify the environment compromising the availability of cloud computing services, and to protect resources, the current paper proposes a security policy that controls the authority to access the resources for cloud computing services by applying the authentication policy of user authentication agents. The proposed system with its policy of the authority to access the resources ensures seamless and secure cloud computing services for users.

• Convergence Security Journal
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• v.8 no.4
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• pp.51-56
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• 2008

A combination of VPNs and dial-up access, such as DSL and Cable, usually provides the cost-effective solution as the substitution of private networks on high-cost leased line. The business demand for high availability has increased with VPN spreading. This paper presents the schemes for a high availability of network access and a load balancing of network traffic in VPN gateways by using multiple links or multihoming capability based on active-active approach. The high availability and load balancing of network links can be achieved by duplicating external network access into multiple independent links. This can provide a continuous network connection to internal users even if one of the links is failed. Moreover, it can provide twice network bandwidth by distributing the traffic into the links. Static and dynamic algorithms are proposed as the load balancing algorithms.

• International Journal of Knowledge Content Development & Technology
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• v.2 no.1
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• pp.5-16
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• 2012

This study analyzes the availability of access features in children's non-fiction as compared to their prevalence in adult non-fiction because such features are an important part of the research process increasingly demanded of younger and younger students in schools. Access features studied include: table of contents, index, bibliography, endnotes/footnotes, glossary, and suggestions for further reading list. This study found that children's non-fiction books were less likely to include bibliographies or endnotes, but more likely to include glossaries or suggested reading lists. Tables of contents and indexes were the two most popular access features in each section. Results are divided by Dewey Decimal Classification classes.

• Proceedings of the KSRS Conference
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• v.1
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• pp.212-215
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• 2006

This paper describes several reliability models to estimate COMS ground segment availability and shows assessed availability according to GS function. Due to a back-up concept among three ground center, SOC will have all H/W and S/W module to be installed in MSC and KOSC site. Therefore, all configurations and availability parameters for H/W and S/W modules in MSC and KOSC are assumed as equal with those in SOC, if related modules have same function. Prior to access availability over COMS GS function, Availability related to fundamental configuration such as series, parallel, partial operation, and module combined H/W and S/W is described. Consequently, all functions are expected to operate with more than 99% of availability.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.10
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• pp.481-489
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• 2020

The study examines the role of facilitating conditions and user habits in the use of technology in Online Learning Platform (OLP) in Indonesia. The adoption of online learning, persistence, and learning results in online platforms is essential for ensuring that education technology is implemented and gets as much value as possible. People who use technology and systems will embrace new technologies even more. This quantitative study is based on a survey of 254 respondents, who were active users of the technology, and considers the facilitating conditions and user habits variables. Two research hypotheses were tested using the Partial Least Square-Structural Equation Modeling method. Cronbach's Alpha, path coefficient, AVE, R-square, T-test were applied. The results showed that the factors significantly influence the Online Learning Platform technology behavioral intention. This impact is primarily associated with the availability of the resources required to use OLP technology. The availability of these resources includes supporting infrastructures such as widespread Internet access, easy access to mobile devices, and file sizes that affect access speed. The findings of this study suggest that it is necessary to introduce and increase the availability of resources for using OLP technology, and familiarize people with the technology features.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.8
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• pp.3455-3473
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• 2016

Cloud computing is a paradigm in which information is permanently stored in servers on the Internet and cached temporarily on clients. Virtual private network (VPN) is the most widely used technology for secure cloud access. Unfortunately, VPN-based cloud services become unavailable when a VPN failure occurs. In this paper, we propose a new scheme to improve the availability of VPN connections against such failures, called high-availability virtual communication (HAVC). Unlike most of the multipath transmission schemes in the literature, the proposed scheme is implemented by using a virtualization technique, and its protocol functions are independent of existing networks - potential clients are not required to modify their applications or operating systems. Simulation results show that the HAVC can not only tolerate VPN failures but also achieve high transmission performance.

• Journal of Information Processing Systems
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• v.8 no.2
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• pp.263-278
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• 2012

The data grid provides geographically distributed resources for large-scale applications. It generates a large set of data. The replication of this data in several sites of the grid is an effective solution for achieving good performance. In this paper we propose an approach of dynamic replication in a hierarchical grid that takes into account crash failures in the system. The replication decision is taken based on two parameters: the availability and popularity of the data. The administrator requires a minimum rate of availability for each piece of data according to its access history in previous periods, but this availability may increase if the demand is high on this data. We also proposed a strategy to keep the desired availability respected even in case of a failure or rarity (no-popularity) of the data. The simulation results show the effectiveness of our replication strategy in terms of response time, the unavailability of requests, and availability.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.3
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• pp.579-588
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• 2019

Industrial control systems consist of various physical devices such as sensors, actuators. Security Infringement such as waterworks facilities Remote Access Infringement and power control systems Infection have been occured by vulnerability of Access Control. Access control to physical devices must be fulfilled with a reliable system. However, Having a single access control system inside company can not guarantee reliability. In addition, when single access control is struggled with error or infringement, access control system is totally unavailable. so system requires a additional access control method or system. In this paper, we proposed access control mechanism for reliable and stable operation using blockchain and smart contract. Proposed Mechanism using trust score to consider resources to be consumed depending on each industrial environment in consideration of the industrial control system where availability is more important than integrity and confidentiality. Unlike other blockchain-based access control system, proposed system is designed for the currently operating industrial control system.

• Journal of information and communication convergence engineering
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• v.8 no.1
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• pp.40-44
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• 2010

opportunistic spectrum access (OSA) allows unlicensed users to share licensed spectrum in space and time with no or little interference to primary users, with bring new research challenges in MAC design. We propose a cognitive MAC protocol using statistical channel information and selecting appropriate idle channel for transmission. The protocol based on the CSMA/CA, exploits statistics of spectrum usage for decision making on channel access. Idle channel availability, spectrum hole sufficiency and available channel condition will be included in algorithm statistical information. The model include the control channel and data channel, the transmitter negotiates with receiver on transmission parameters through control channel, statistical decision results (successful rate of transmission) from exchanged transmission parameters of control channel should pass the threshold and decide the data transmission with spectrum hole on data channel. A dynamical sensing range as a important parameter introduced to maintain the our protocol performance. The proposed protocol's simulation will show that proposed protocol does improve the throughput performance via traditional opportunistic spectrum access MAC protocol.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.9
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• pp.2082-2090
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• 2013

As rehabilitation psychology analysis system which manages examination information becoming more popular, interoperability, portability and security are becoming major concerns of modern computing. We propose a security model on the type information based access control system for rehabilitation psychology analysis that can enhance both security and availability by separating the functions delivered from object-oriented databases to solve these problems. We apply the access control model specifically to enhancement of security system and also perform a test to verify the security and availability of our model.