• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.8
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• pp.2096-2105
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• 1998

As there can be coincident bursts which may result in congetsion in a node of ATM network, reactive flow control schemes are required to guarantee user's Quality of Service. But, the high speed characteristics of ATM networks make it difficult to control source transmission rate in reacting to congestions in intermediate nodes. Therefore, flow control in Customer Premise Network may be more efficient than end-to-end flow control. In this paper, we propose a management model for flow ontrol in CPN and new Network Access Flow/Congestsion control scheme to utilize efficiently Virtual Path Connection.

• Journal of Communications and Networks
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• v.13 no.1
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• pp.70-76
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• 2011

This paper presents the unified user equipment (UE) baseband modulation and demodulation (modem) hardware platform architecture to support multiple radio access technologies. In particular, this platform selectively supports two systems; one is HEDGE system, which is the combination of third generation partnership project (3GPP) Release 7 high speed packet access evolution (HSPA+) and global system for mobile communication (GSM)/general packet radio service (GPRS)/enhanced data rates for GSM evolution (EDGE), while the other is LEDGE system, which is the combination of 3GPP Release 8 long term evolution (LTE) and GSM/GPRS/EDGE. This is done by applying the flexible pin multiplexing scheme to a hardwired pin mapping process. On the other hand, to provide stable connection, high portability, and high debugging ability, the stacking structure is employed. Here, a layered board architecture grouped by functional classifications is applied instead of the conventional one flatten board. Based on this proposed configuration, we provide a framework for the verification step in wireless cellular communications. Also, modem function/scenario test and inter-operability test with various base station equipments are verified by system requirements and scenarios.

• Journal of Digital Contents Society
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• v.18 no.5
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• pp.983-987
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• 2017

Multi-homing mobile router separates network for user connection and network for internet access using various interfaces for internet access. This paper proposes a load balancing metric in order that multi-network mobile router distributes its traffic to one of several heterogeneous network interfaces. To evaluate the performance of the load balancing metric, experiments on traffic balancing is performed on real commercial networks were used in Korea and Hong Kong.

• Journal of the Korea Society of Computer and Information
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• v.10 no.4 s.36
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• pp.305-313
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• 2005

Spyware is any software which employs a user's Internet connection in the background without their knowledge or explicit permission. The installation of spywares is generally done in a sneaky, misleading or unannounced manner. It does not only compromise the security and privacy of affected users but also be an obstruction to the digital convergence and ubiquitous computing environments. This paper provides a summary of the definition, status, risk analysis, and security controls of the spywares. Furthermore, this paper suggests additional controls which should be considered at an individual, organizational and national perspective.

• Journal of Digital Contents Society
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• v.15 no.1
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• pp.77-85
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• 2014

The Service Oriented Architecture has been adopted to be able to handle various types of user requirement flexibly. This concept supports to identify service units, organize that units and integrate them to make a software system. In this paper, we introduce SOA to improve legacy system for reducing duplicated functions and relax the difficulties of maintenance. We try to analyze function flow of warehouse management system and reorganize it to reduce duplicated implementation. Also the system architecture is tried to improve considering connection with other ERP systems.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.781-786
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• 2007

According to increase in supply of public rental housing, in connection with support plan of housing welfare from government, necessity of maintenance management is coming to be important. By analyzing characteristics of public rental housing and maintenance management system, this study grasped developmental possibility of a web based maintenance management system as well as a critical point for improvement of problem and elevation of efficiency about maintenance management process. As we present not only useful possibility of ubiquitous equipments utilizing IT like PDA but effectiveness by using, based on this result, we represent course of improvement to systematic development for user that complement the existing maintenance management system which is currently developed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.1A
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• pp.7-16
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• 2003

Handover is very important to support the mobility of user because wireless ATM networks have smaller cell size such as micro/pico cell for broadband mobile multimedia service In this paper, we propose dynamic path reservation handover scheme for fast inter-MSC (Mobile Switching Center) handovers To reduce the handover delay for connection re-routing, the proposed scheme reserves virtual channels from nearest common node to neighbor MSC in advance Especially, our handover scheme predicts the number of inter-MSC handover calls at each period by the prediction algorithm and reserve virtual channels The simulation and analysis results show that our scheme reduce handover complexity and has higher reservation channel utilization, compared with DVCT scheme.

• Journal of the Korean Institute of Educational Facilities
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• v.11 no.5
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• pp.35-43
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• 2004

The purpose of this study is to produce the architectural basic data for the planning of Kindergarten attached to the elementary school. For this study, 19 Kindergartens in Taegu city was selected and investigated as the sample of the survey. The results of this study are as follows. 1) 'The Independent-type' can be general application of the kindergarten's layout type. And it must be considered about connection with some public facilities in the elementary school. 2) The architectural guidelines for each rooms can be suggest as follow. Classrooms and the Playroom should be existed independently and be located about suitable area. The Location of the Playground should be considered about kindergartener's approach, distance from elementary school and noise. And the Playground needs washstands and shade resting places. In the Classrooms and the Playroom, the designer should consider about suitable area and storage. 3) The flexible space-program is necessary for each management type.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.3
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• pp.103-109
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• 2003

The validity of measured data is fundamental factor for the power system automation Measured values could have errors that are caused by the communication errors and malfunctioning measuring devices. The accuracy and reliability of measured values at a substation is an important condition for robust and fault tolerant automata. Errors can be reduced by state estimation, however, global reliability of state estimation goes down in case of the existence of some bad data In this paper, a least square state estimation and bad sensor detection algorithm based on chi-square theory, ale proposed and it is applied to a domestic 154kV distribution substations. A simulator together with user friendly graphic users interface is developed using C language and Visual Basic. TCP/IP is equipped for future connection with other operation systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.8
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• pp.1726-1731
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• 2003

The firewall is generally used to protect the internal information system from intruders and hackers who attack through the Internet. However, it is very difficult for a user to verify the performance of the firewall as well as the difference of the performance for the operating mode such as Bridge Mode and Gateway Mode. In this paper, the performance of a firewall on the operating systems or windows 2000, Linux, and FreeBSD is compared. Finally, The performance of a firewall on the FreeBSD is compared at different operating modes and the effect of the number of rules by testing throughput of a firewall is analyzed.