• Journal of the Korea Society of Computer and Information
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• v.6 no.4
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• pp.138-145
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• 2001

In this paper, we propose fuzzy closed BCMP queueing network model for the performance evaluation of distributed processing system. Which has the ambiguous service requirements of job to servers and service rates of server according to network environments. This model can derive the measures for system Performances using fuzzy mean value analysis which can process the fuzzy factors. Computer simulation has been performed for verifying the effectiveness of derived equations of performance evaluation according to service requirements of job and the numbers of clients.

• IEMEK Journal of Embedded Systems and Applications
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• v.18 no.2
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• pp.67-73
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• 2023

Tree routing is one of appropriate routing schemes in wireless sensor network because the complexity of this approach is relatively low. But, congestion at a specific node may happen because a parent node toward a sink node is usually selected in one hop way, specially where large number of node are deployed. As feasible solution for this problem, multiple paths and sinks schemes can be applied. However, the performance of these schemes are not proved and analyzed yet. In this paper, we conduct diverse simulaton scenarios performance evaluation for these cases to identify the improvement and analyze the impact of schemes. The performance is measured in the aspects of packet transmission rate, throughput, and end-to-end delay as a function of amount of network traffic.

• Korean Journal of Social Welfare
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• v.63 no.1
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• pp.57-84
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• 2011

This study aims to analyze a whole network effectiveness by expanding the unit of analysis beyond individual organizations in a network into network-level collaborative relations. Data for the analysis were drawn from the evaluation reports and surveys of leaders, mid-level managers, and staff members of the organizations participating in 'Community Network Building' project which was funded by Community Chest of Korea and carried out by the Academy of Korean Social Welfare Administration from November 2006 to November 2009. For the analysis, three out of the 10 networks established in diverse local communities were selected. Based on the survey conducted on the participating organizations and the center organization of each network, we analyzed the structural characteristics of interorganizational network at a network-level. Second, to analyze effectiveness of the whole network, we employed a multiple stakeholders perspective and examined the relations between the whole network's structure and its effectiveness. The findings showed that the whole network effectiveness is higher when the network is more centralized around the hub organization and more stable. The significance of this study is that it is provided and tested a new framework for network effectiveness evaluation by combining the two network effectiveness evaluation framework of Provan and Milward's with evolutionary organizational theory.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.3
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• pp.1113-1135
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• 2018

Existing trust evaluation models for wireless sensor networks can accurately and objectively evaluate trust value of nodes, but the nodes' energy saving problem was ignored. Especially when there are a few malicious nodes in a network, the overall trust value calculation for all nodes would waste lots of energy. Beside that, the network failure caused by nodes death was also not considered. In this paper, we proposed a method for avoiding energy hole which applied trust evaluation models and a trust evaluation method based on information entropy, so as to achieve the purpose of improving nodes utilization. Simulation results show that the proposed method can effectively improve nodes utilization, and it has reasonable detection rate and lower false alert rate compared to other classical methods.

• International Journal of Computer Science & Network Security
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• v.21 no.1
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• pp.55-63
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• 2021

The design functionality put forward by mapping the interactiveness of information. The presentation of such information with the user interface model indicates that the guidelines, concepts, and workflows form the deliverables and milestones for achieving a visualized design, therefore forming the right trend is significant to ensure compliance in terms of changing consideration and applying evaluation in the early stages. It is evidenced that prototype design is guided by improvement specifications, includes modes, and variables that increase improvements. The study presents five user interface testing methods. The testing methods are heuristic evaluation, perspective-based user interface testing, cognitive walkthrough, pluralistic walkthrough, and formal usability inspection. It appears that the five testing methods can be combined and matched to produce reasonable results. At last, the study presents different mobile application designs for student projects besides the evaluation of mobile application designs to consider the user needs and usability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.2
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• pp.192-201
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• 1993

According to technical advances of telecommunication, communication network has changed to digital transmission from analog transmission network. In the long run, current network will be altered into ISDN which makes end-to-end digital communication. This transition of communication network brings about an important questions for networking plan, administration, and speech quality in order to achieve the effective and advanced telecommunication. Speech quality criterions and degradation factors of digital communication system differ from those of existing analog system because of other characteristics like single echo. It is, therefore, necessary to design new criterions and specifications for digital communication network. This Paper describes the relation between speech communication and speech transmission quality and describes the implementation of model system for quality evaluation of digital speech communication network. In addition, some applications of model system implemented are proposed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.11
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• pp.3935-3949
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• 2021

With the rapid development of Internet and big data technology, various online social network platforms have been established, producing massive information every day. Hot topic discovery aims to dig out meaningful content that users commonly concern about from the massive information on the Internet. Most of the existing hot topic discovery methods focus on a single network data source, and can hardly grasp hot spots as a whole, nor meet the challenges of text sparsity and topic hotness evaluation in cross-network scenarios. This paper proposes a novel hot topic discovery method across social network based on an im-proved LDA model, which first integrates the text information from multiple social network platforms into a unified data set, then obtains the potential topic distribution in the text through the improved LDA model. Finally, it adopts a heat evaluation method based on the word frequency of topic label words to take the latent topic with the highest heat value as a hot topic. This paper obtains data from the online social networks and constructs a cross-network topic discovery data set. The experimental results demonstrate the superiority of the proposed method compared to baseline methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.6B
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• pp.921-929
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• 2010

Group communication that involves the setup of a list of users has been a topic of interest in mobile industry. Push to Talk over Cellular (PoC), a group communication service for cellular phone network, is a type of half duplex communications that allows a single person to reach an active talk group without making several calls, but a single button press. Based on this service, we build a new protocol called Push to Talk over Mobile Wimax that uses group communication service in 802.16e network. Also, weper formed simulation to verify and evaluate performance of the designed service in Mobile Wimax network. From the results of performance evaluation, network administrators can evaluate the stability of network and make a better of network's shortcoming and have decision to build the robust network.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.2
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• pp.373-384
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• 2014

The social network service is the bidirectional media that many users can build relations not only friends but also other people. However, a process to approach in the social network is so simple that untrustable information, which malignant users make, is spreaded rapidly in many the social network uses. This causes many users to suffer material or psychological damages. Because of openness in the social network, there will be higher risk of the privacy invasion. Therefore, sensitive information should be transferred or provided only to reliable users. In general, because many users exchange among one hops, many researches have focused on one hop's trust evaluation. However, exchanges between users happen not only one joint bridege but also far nodes more than two nodes on account of dense network and openness. In this paper we propose the efficient scheme combining transitivity and composability for remote users.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.4
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• pp.1817-1836
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• 2020

Network convergence is considered as one of the key solutions to the problem of achieving future high-capacity and reliable communications. This approach overcomes the limitations of separate wireless technologies. Efficient interface selection is one of the most important issues in convergence networks. This paper solves the problem faced by users of selecting the most appropriate interface in the heterogeneous radio-access network (RAN) environment. Our proposed scheme combines a hierarchical evaluation of networks and game theory to solve the network-selection problem. Instead, of considering a fixed weight system while ranking the networks, the proposed scheme considers the service requirements, as well as static and dynamic network attributes. The best network is selected for a particular service request. To establish a hierarchy among the network-evaluation criteria for service requests, an analytical hierarchy process (AHP) is used. To determine the optimum network selection, the network hierarchy is combined with game theory. AHP attains the network hierarchy. The weights of different access networks for a service are calculated. It is performed by combining AHP scores considering user's experienced static network attributes and dynamic radio parameters. This paper provides a strategic game. In this game, the network scores of service requests for various RANs and the user's willingness to pay for these services are used to model a network-versus-user game. The Nash equilibria signify those access networks that are chosen by individual user and result maximum payoff. The examples for the interface selection illustrate the effectiveness of the proposed scheme.