• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.10C
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• pp.1033-1044
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• 2003

In this paper, we propose security management architecture that manages efficiently security systems that are produced by different companies and programmable middleware that can reduce the load of management traffic. The proposed architecture applies programmable networks technology to policy based network management (PBNM). The proposed architecture manages and cooperates various security systems using security policy. Also, the programmable middleware provides convenience of management and reduces the overhead of a policy server by translating security policy into execution command. In addition, using programmable middleware, an administrator can manage various security systems that are produced by different companies. We showed that the programmable middleware could reduce the load of management traffic by comparing processing time for enforcing and transferring of policies/messages between the proposed architecture and PBNM architecture.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2B
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• pp.192-202
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• 2004

In this paper we have proposed policy-based network management system architecture for Internet QoS support Mobile IP networks that is divided into four layers(application layer, information management layer, policy control layer, device layer), then we propose an implementation strategy of policy-based network management system to enforce various control and network management operations and a model of policy server using SCOPS(Simple Common Open Policy Service) protocol that is developed in this research. For policy-based mobile IP network management system implementation, we have derived four policy classes(access control, mobile IP operation, QoS control, and network monitoring) and we showed operation procedures for each policy scenarios. Finally we have implemented Internet QoS support policy-based mobile IP network testbed and management system and verified out DiffServ policy enforcement behaviors for a target class service that is arranged a specific bandwidth on network congestion conditions.

• Journal of Digital Convergence
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• v.12 no.8
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• pp.265-270
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• 2014

This study in coping with the current trend is to propose the environment for training 3-Tier App development being focused on the system to develop mobile applications where its related developers are scarce. Design and implementation of training system for the development of 3-Tier App in this paper is to realize the environment for software development for colleges as same as that in IT companies. For 3-Tier App development training system, 3 students with 3 computers work as a group. The above-mentioned 3 computers include a computer for development, Gateway server, and DB server together with legacy system. Also, each of the 3 students shall be given roles of the foregoing sections. We have educated 3-Tier App training system as a practical class for 64 students in junior students of computer information major. Through training session, it was confirmed that we can foster the students as custom-made talents who understand company's development environment. Also, the Comparison of 3-Tier and Stand-alone App Development Training System for 10 distinct description, we know that 3-Tier app development training system was very superior to stand-alone app development training system in the educational effects.

• Journal of Korea Spatial Information System Society
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• v.1 no.2 s.2
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• pp.5-20
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• 1999

Recently, the new software paradigm in information technology (IT) is the component-based development (CBD) technology that has brought as a result of the distributed computing environment (DCE). The CBD has reduced a program developing time and has been designed to make a distributed computing environment easier in the Internet and Intranet environments. These changes of software technology have influence on the geographic information system (GIS) and the CBD technology is highly needed as a point of view of the technique and policy of the geographic information system. In this paper, we designed and implemented an Enterprise Server for the efficient development and management of GIS components. Especially, the Enterprise Server was developed with the Enterprise JavaBeans Specification 1.1 that had been proposed as an industry standard by the Sun Microsystems. The Enterprise Server can allows users to manage the Unified Modeling Language (UML) and Design Patterns for the development of GIS components, develop a GIS component container which obeyed the Open Geodata Interoperability Specification (OpenGlS), manage spatial metadata through a spatial XML (eXtensible Markup Language) engine, and implement a TESTBED server for testing and verification of developed GIS components.

• Journal of KIISE:Computer Systems and Theory
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• v.37 no.4
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• pp.195-204
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• 2010

Due to improved wireless communication technologies, it is possible to provide multimedia streaming service for mobile device clients like PDAs and cellphones. Wireless networks are serviced on low bandwidth channels and mobile devices work on limited hardware specifications. In these conditions, transcoding technologies are needed to adapt the media for streaming services to given mobile environments. To transcode from the source media to the target media for corresponding grades, transcoding servers perform transcoding jobs as exhausting their resources. Since various transcoding loads occur according to the target transconding grades, an effective transcoding load balancing policy is required among transcoding servers. In addition to transcoding process, servers should maintain QoS streams for mobile clients for total serviced times. It requires real-time requirements to support QoS for various mobile clients. In this paper, a new transcoding load distribution method is proposed. The proposed method can be driven for fair load balance between distributed transcoding servers. Based on estimated transcoding time, movie information and target transcoding bit-rate, it provides fair transcoding load distribution and also performs admission control to support QoS streams for mobile clients.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.9_10
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• pp.466-475
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• 2008

Owing to the improved wireless communication technologies, it is possible to provide streaming service of multimedia with PDAs and mobile phones in addition to desktop PCs. Since mobile client devices have low computing power and low network bandwidth due to wireless network, the transcoding technology to adapt media for mobile client devices considering their characteristics is necessary. Transcoding servers transcode the source media to the target media within corresponding grades and provide QoS in real-time. In particular, an effective load balancing policy for transcoding servers is inevitable to support QoS for large scale mobile users. In this paper, the transcoding load estimation algorithm is proposed for load balance on the distributed transcoding environments. The proposed algorithm estimates transcoding time from transcoding server information, movie information and target transcoding bit-rate. The estimated transcoding time is proved based on experiments.

• Journal of Digital Convergence
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• v.15 no.10
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• pp.253-260
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• 2017

Authenticated key agreement in multi-server environments is one of very important security issues because only authorized user needs to access their data and services. To support this issue, numerous schemes have been proposed over recent years. Recently, Shin showed the security weaknesses in the previous scheme and proposed an improved scheme called SIAKAS to solve them. Unfortunately, this paper shows that SIAKAS is still weak against application server impersonation attack and could be traceable to attackers. To solve the problems in SIAKAS, we propose an untraceable authenticated key agreement scheme, denoted by UAKAS. UAKAS efficiently solves security and privacy issues in SIAKAS and the related schemes and could reduce the operation overhead at least 12% compared to them.

• Journal of Digital Convergence
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• v.13 no.9
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• pp.287-295
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• 2015

The IPTV service has to be converted into an unified media format that fits for a variety of terminal equipments in terms of the bulk high-capacity media contents, and is spending a lot of time in the conversion time of contents including the process of collecting the media contents and extracting the information for conversion. In order to solve the problem, this paper designed the database in accordance with the automatic collection of time, and proposed a system that could increase the productivity of the contents through the automation process of the entire process using the media server and the transcoder. The media server collected contents and extracted information automatically with respect to the contents servers placed in specific locations and the media files of the storage whereas the transcoder conducted the automatic upload of the converted results to a specific server through the process of automatic conversion. As a result, the various convergence through compared to existing conversion method could minimized unnecessary waste of time.

• Journal of Digital Convergence
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• v.13 no.9
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• pp.235-242
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• 2015

Social network technology has been increasing interest in the big data service and development. However, the data stored in the distributed server and not on the central server technology is easy enough to find and extract. In this paper, we propose a big data management techniques to minimize the processing time of information you want from the content server and the management server that provides big data services. The proposed method is to link the in-group data, classified data and groups according to the type, feature, characteristic of big data and the attribute information applied to a hash chain. Further, the data generated to extract the stored data in the distributed server to record time for improving the data index information processing speed of the data classification of the multi-attribute information imparted to the data. As experimental result, The average seek time of the data through the number of cluster groups was increased an average of 14.6% and the data processing time through the number of keywords was reduced an average of 13%.

• Journal of Digital Convergence
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• v.17 no.2
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• pp.155-161
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• 2019

Electroencephalography (EEG), a representative method of identifying temporal and spatial changes in brain activity, is a voluntary electrical activity measurable in the human scalp. Various interface technologies have been provided to control EEG activity, and it is possible to operate a machine such as a wheelchair or a robot through brainwaves. The characteristics of EEG data are collected in various types of channels in real time, and a server system for analyzing them is required to have an independent and lightweight system for the platform. In these days, the Spring platform is used as a large business server as an independent, lightweight server system. In this paper, we propose an EEG analysis system using the Spring server system. Using the proposed system, the reliability of EEG control can be enhanced, and analysis and control interface expansion can be provided in various aspects such as game and medical areas.