• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.12
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• pp.1179-1185
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• 2013

Trend of next generation satellite communication network is distribution and enlargement of network structure with increased network terminals, and traffic which use satellite communication is increasing and frequently occurring. Under specific satellite communication environment that various communication device dynamically forms a network domain and frequently exchanges the data, data-centric publish/subscribe data exchange is more suitable than server/client data exchange. So, this paper analyze DDS performance for application of DDS standard to distribution network management system which aims to efficiently manage limited satellite resource, and also this paper covers comparative study on DDS and SNMP(server/client data exchange). Study compares DDS and SNMP using OPNET, and result of study is analyzed from a network layer performance perspective.

• Journal of Korea Multimedia Society
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• v.10 no.12
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• pp.1632-1644
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• 2007

Wireless Mesh Networks aim to attain large connectivity with minimum performance degradation, as network size is increase. As such, scalability is one of the main characteristics of Wireless Mesh Networks that differentiates it from other wireless networks. This characteristic creates the need for bandwidth efficiency strategies to ensure that network performance does not degrade as the size of the network increase. Several researches have been done to realize mesh networks. However, the researches conducted were mostly focused on a per TCP/IP layer basis. Also, the studies on bandwidth efficiency and bandwidth improvement are usually dealt with as separate issues. This paper aims to simultaneously study bandwidth efficiency and improvement. Aside from optimizing the bandwidth given a fixed capacity, the capacity is also increased using results of physical layer studies. In this paper, the capacity is improved by using the concept of non-overlapping channels for wireless communication. A channel allocation scheme is conceptualized to choose the transmission channel that would optimize the network performance parameters with consideration of chosen Quality of Service (QoS) parameters. Network utility maximization is used to optimize the bandwidth after channel selection. Furthermore, a routing scheme is proposed using the results of the network utilization method and the channel allocation scheme to find the optimal path that would maximize the network gain.

• The Journal of Information Systems
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• v.18 no.3
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• pp.47-70
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• 2009

Social network is one of the representative analytical method of the complexity theory and this research analyzed various and unique strategic alliance model of e-business domain using social network technique. A lot of small and medium firms of e-business field had developed many useful type of strategic alliances for the firms tried to maximize the effect of advertisement, marketing and to make up for their weak points and to compete with huge company with capital strength long before. But it is too rare to analyze the structure of the firm networks and to study the evolution and extension of business model considered the role of each company in the network. Social network analysis helps each firm's network easily visualized and completely modelized. Additionally, this paper cries to analyze the relationship between the role of hub and broke in the firm networks for strategic alliance, and financial performance. We demonstrate the firm with finer business model to the business environment can make higher financial performance. This implies that the firm that can create new finer business model, will lead the network of e-business firms and evolve the industry of e-business.

• The Journal of Korean Association of Computer Education
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• v.10 no.2
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• pp.77-87
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• 2007

The purpose of the study was to investigate the effects of social network centrality variables on students' performance in blended learning environment in a higher educational institution. Using data from 36-student course on Learning Theories and Their Implications on Instructional Design Practices, the researcher empirically tested how social network centrality variables - such as friendship network centrality, advice network centrality, and adversary network centrality - are correlated with academic achievement measures. Results indicate, as hypothesized, the friendship and advice centrality positively correlate with, whereas the adversary centrality being negatively correlate with application performance measures and test scores. The size and quality of posted online discussions are positively and strongly correlated with the advice network centrality.

• Journal of the Korea Society of Computer and Information
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• v.12 no.2 s.46
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• pp.93-102
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• 2007

Firewall system is a security system for protect the network and is needed for constructing the trusted network. However, these firewall systems deteriorate the performance of whole network in about 60% because of Inefficiency policy establishment and unnecessary traffic occurrence. Therefore, there is a strong needs to establish the network performance elevation, efficient operation and reassignment of the firewall system. In this dissertation, we will analyze how each functionalities of the firewall system affect to the network performance via using a simulation result according to functionality of the firewall system and propose a exclusive firewall system for the efficient network operation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.4A
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• pp.579-585
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• 2000

This paper analyzes and compares the blocking performance of all-optical wavelength-routed networks providing circuit switching among users. A connection between two nodes along a particular path must use a single wavelength on all hops, or links, within the path. We then calculate the blocking probability along a lightpath with wavelength conversion in a network with an arbitrary topology and show the network performance improvement offered by node with limited translation technology. We also propose a new schematic method for the performance analysis of different types of network architecture which is composed of nodes with or without wavelength conversion(NC, FC or LC).

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.10
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• pp.2548-2566
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• 2012

This paper derives two main end-to-end performance metrics, namely the spatial capacity density and the average end-to-end delay of the multi-hop wireless ad hoc networks with multi-antenna communications. Based on the closed-form expressions of these performance metrics, three hopping strategies, i.e., the closest neighbor, the furthest neighbor and the randomly selected neighbor hopping strategies have been investigated. This formulation provides insights into the relations among node density, diversity gains, number of hops and some other network design parameters which jointly determine network performances, and a method of choosing the best hopping strategy which can be formulated from a network design perspective.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.11
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• pp.1119-1127
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• 2007

This paper is concerned with a performance analysis using a wired/wireless hybrid network based on Common Industrial Protocol(CIP). For the performance analysis, the data transmission time, average end-to-end delay and throughput between DeviceNet and the wireless devices are investigated. The experimental results show the performance in terms of the polling/COS service time of CIP based hybrid network.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.5
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• pp.218-225
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• 2001

This paper analyses the performance of network system using the CAN(Controller Area Network) protocol. Given messages are assumed to be scheduled by the DMS(Deadline Monotonic Scheduling) algorithm. The mathematical models for time-delay that can be occurred between CAN nodes are defined. The effectiveness of modeling is shown by comparing the difference of time-delay between simulations and practical experiments. We analyse the results according to the variation of factors, such as the number of nodes, the transmission speed, the message size and the number of aperiodic messages through simulation and confirm the real-time performance of lower priority messages. We also investigate the real-time performance of periodic messages when aperiodic message generates.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.473-475
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• 2006

FieldBus communication systems in industrial wired and wireless network may cause the degradation of the TCP performance due to the racket loss. TCP is particularly targeted at the wired networks, a packet loss is assumed to be caused by the network congestion. As a result, the performance of TCP decreases significantly when used over networks that exhibit a high bit error rate. In order to solve this problem, this paper designs and implements the WFSnoop mechanism which offers a fast local retransmission. The proposed mechanism does not require any changes in customer premises. Base on the simulation in the wired and wireless network environment, we analyzed the performance of the WFSnoop mechanism.