• Journal of the Korea Society of Computer and Information
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• v.3 no.1
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• pp.125-148
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• 1998

The use of shaping mechanism, realized by means of a leaky bucket based algorithm on input traffic of an ATM network allows to achieve higher utilization of network resources, and to guarantee the quality of service requested by the users. The functionalities of the shaping mechanism based on leaky bucket, are characterized by the token pool sire and by input queue size. In this paper we have analyzed, using simulations, the effect on the quality of service in ATM network of leaky bucket algorithm when shaper parameters described above are changed.

• International Commerce and Information Review
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• v.10 no.4
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• pp.125-151
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• 2008

Website service quality is widely accepted as one of the key determinants of online business success. Several studies identified key factors that determine the website service quality factors appropriate for online business environments. A convention and visitors bureau (CVB) website is a service portal that delivers information online about a destination so users can develop an overall image of the location. CVBs struggle to deliver positive destination images because the competition among destinations to host conventions is intense. In spite of the important role of CVBs and the beneficial spillover effect of CVBs, there are few studies available reporting on the unique service qualities of a CVB website. The primary purpose of this study was to examine the determining factors that are appropriate for CVB websites from the meeting planners' perspective. The research questions arc: What are the determining factors of service quality of a CVB website? Do the determining factors of CVB website service quality positively influence meeting planners' satisfaction? The new conceptual framework was developed from a variety of destination marketing and Internet marketing concepts: e-servicescape management, web community network, Internet service encounter management, and online system quality. Empirical results indicate that three of the four factors, that is, e-servicescape, web community network, and online system quality are important determinants in evaluating CVB website service quality. The findings also show that three determinants have significant and positive influence on meeting planners' satisfaction. The findings from this study will provide meaningful advice for CVB website quality management. To enhance the CVB website service quality and satisfaction level of meeting planners, these three determinants' should be considered of the utmost strategic importance and priority.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.8
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• pp.2783-2804
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• 2021

In the network function virtualization environment, dynamic changes in network traffic will lead to the dynamic changes of service function chain resource demand, which entails timely dynamic adjustment of service function chain resource configuration. At present, most researches solve this problem through virtual network function migration and link rerouting, and there exist some problems such as long service interruption time, excessive network operation cost and high penalty. This paper proposes a dynamic adjustment method of service function chain resource configuration for the dynamic changes of network traffic. First, a dynamic adjustment request of service function chain is generated according to the prediction of network traffic. Second, a dynamic adjustment strategy of service function chain resource configuration is determined according to substrate network resources. Finally, the resource configuration of a service function chain is pre-adjusted according to the dynamic adjustment strategy. Virtual network functions combination and virtual machine reusing are fully considered in this process. The experimental results show that this method can reduce the influence of service function chain resource configuration dynamic adjustment on quality of service, reduce network operation cost and improve the revenue of service providers.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.10
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• pp.40-46
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• 2009

Recently CAN (Controller Area Network) is widely used as an in-vehicle networking protocol for intelligent vehicle. The identifier field (ID) of CAN is used not only to differentiate the messages but also to give different priorities to access the bus. This paper presents a dynamic 10 allocation algorithm in order to enhance the real-time quality-of-service (QoS) performance. When the network traffic is increased, this algorithm can allocate a network resource to lower priority message without degradation of the real-time QoS performance of higher priority message. In order to demonstrate the algorithm's feasibility, message transmission delays have been measured with and without the algorithm on an experimental network test bed.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.8
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• pp.59-66
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• 2009

Recently, as the expectation about the IPTV (Internet Protocol TV) service quality is rapidly increased by the development of the national high-speed internet and TPS (the Triple Play Service : data + image + audio) service Therefore, the enactment of the national quality standards about the IPTV service quality guaranteeing the real time video quality of a subscriber and the international standards are hastily needed. This paper built a test bed with the network domain and the subscriber set-top box domain including the headend area and commercial network characteristic in order to test in the environment which is similar to the characteristic of the service business network. And by using the constructed environment, the characteristics required for SLA(service Level Agreement) of the IPTV service are presented as the quality test according to the service environment change.

• The KIPS Transactions:PartC
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• v.16C no.6
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• pp.717-724
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• 2009

The most important issue for successful deployment of IPTV service is the service quality. In this paper, we first choose critical quality metrics belonging to each layer of IPTV service transmission architecture and then analyze the relation between the quality parameters. For this purpose, we implement a test network that emulates the most practical environment in which IPTV service is provided and repeat measurements on the test network for the chosen metrics. Based on the analysis result, it is shown that packet losses have greater effect on the video quality of IPTV service comparing to delay and jitter.

• The Journal of the Korea Contents Association
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• v.13 no.8
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• pp.371-385
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• 2013

Library and information service (LIS) of academic libraries plays an important role in the education and research activities of universities. Such importance of LIS facilitated much research that defines the quality factors constituting LIS and identifies the importance of them. The previous literature, however, has some limitations. The limitations arise from the interrelationship among the quality factors and the perception gap between users and providers on LIS quality factors. Despite the understanding of the interrelationship and the perception gap, LIS studies to deal with both dimesions synthetically are sparse. Therefore, this paper defines the interrelationship among LIS quality factors as a network model, then identifies the perception gap on LIS quality factors by exploiting the analytic network process. As an early stage study, this paper contributes to helping the quality improvement of acedemic LIS by considering the interrelationship among LIS quality factors and the perception gap on the LIS quality factors between LIS users and providers.

• Journal of Information Processing Systems
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• v.13 no.3
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• pp.546-558
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• 2017

The amount of multimedia traffic over the Internet has been increasing because of the development of networks and mobile devices. Accordingly, studies on multicast, which is used to provide efficient multimedia and video services, have been conducted. In particular, studies on centralized multicast tree construction have attracted attention with the advent of software-defined networking. Among the centralized multicast tree construction algorithms, the group Takahashi and Matsuyama (GTM) algorithm is the most commonly used in multiple multicast tree construction. However, the GTM algorithm considers only the network-cost overhead when constructing multicast trees; it does not consider the temporary service disruption that arises from a link change for users receiving an existing service. Therefore, in this study, we propose a multiple multicast tree construction algorithm that can reduce network cost while avoiding considerable degradation of service quality to users. This is accomplished by considering both network-cost and link-change overhead of users. Experimental results reveal that, compared to the GTM algorithm, the proposed algorithm significantly improves the user-experienced quality of service by substantially reducing the number of linkchanged users while only slightly adding to the network-cost overhead.

• Journal of Communications and Networks
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• v.17 no.2
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• pp.110-117
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• 2015

In mobile social network, it is a critical challenge to select an optimal set of devices to supply high quality service constantly under dynamic network topology and the limit of device capacity in mobile ad-hoc network (MANET). In this paper, a multi-devices composition and maintenance problem is proposed with ubiquitous service model and network model. In addition, a multi-devices composition and maintenance approach with dynamic planning is proposed to deal with this problem, consisting of service discovery, service composition, service monitor and service recover. At last, the simulation is implemented with OPNET and MATLAB and the result shows this mechanism is better applied to support complex ubiquitous service.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3B
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• pp.225-234
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• 2009

Recently IPTV service is penetrating to the ordinary home users very swiftly. One of the first phase of IPTV service is considered to be VoD, and a nationwide availability of the VoD service imposes tremendous pressure to the network resource due to its requirements for the broad bandwidth, the inherent nature of unicast technology, and the large scalability, etc. This work suggests a novel and practical method to the design of network resource for the VoD service. Especially, we explore the distributed content storage problem that takes into account the popularity of the video contents and its corresponding link dimensioning problem that takes into account the grade of service for the flow level quality of service about the VoD service. By assuming a realistic topology for the nationwide IP backbone network of Korea, which is a typical tree topology, we suggest an analytic method for the design of VoD service.