• 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.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.59-64
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• 2008

In this paper, stability and transparency analysis for client/server haptic-based networked virtual environment (NVE) is introduced. From this analysis the appropriate communication structure for the more stable and transparent haptic interactions can be derived. Also, it is possible to expect and compensate the quality deterioration of haptic interactions according to certain network conditions In order to verify the usefulness of the analysis, simple haptic-based NVE application is implemented. For the stability verification, the vibration or strange movement of haptic interface and virtual object are measured under various network states. In addition, the usefulness of the proposed transparency analysis and network delay compensation scheme is verified by comparing distorted and compensated force feedbacks with real force feedback.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.2
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• pp.231-239
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• 2002

This paper gives a comprehensive overview of the SSO solution design on the intranet. SSO described in this paper is based on LDAP, PKI and CA. We designed the data structure to hold many various application services by changing the attribute and DN of LDAP DB. We built LDAP DB using the employee records stored in our organization database. LDAP DB is routinely updated from the database. CA Server that depends on PKI is used to issue the certificates. SHTTP based on SSL is used to protect the data between certificate server and the intranet users.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.6
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• pp.1111-1116
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• 2009

For expression of contour lines in mobile GIS environments, the client needs to receive the numerical data with the topographical map from a server. At this point, a client can't get the entire raw data because of the mobile characteristics. The approach to get representative points and to make isogram by interpolation methods, has some problems. The approach requires huge computing overhead at the client and doesn't guarantee the correctness of the isogram. In this paper, a data structure, algorithm and implementation results for efficient transmission of contour information to a client which is constructed from elevation information at a server, are proposed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.151-154
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• 2008

For expression of isogram in mobile GIS environments, the client needs to receive the value data with the topographical map from a server. At this point, a client can't get the entire raw data because of the mobile characteristics. The approach to get representative points and to make isogram by interpolation methods, has some problems. The approach requires huge computing overhead at the client and doesn't guarantee the correctness of the isogram. In this paper, a data structure, algorithm and implementation results for efficient transmission of contour information to a client which is constructed from a elevation information at a server, are proposed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.929-932
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• 2007

The integrated prevention of disaster management system is collected prevention of disaster data from prevention of disaster relation other systems and smart sensor in USN. This system manages fire fighting facility effectively. The relation equipment which is used in existing and network using "Open Protocols" about under using the support system which is integrated effectively as the destroyer. It connects CCTV, the sensitivity environmental sensor, automatic fire detection equipment and security equipment and air flow equipment system using Internet. The System Server was collected monitoring data at the each equipment and processing by operational scenario. It will verified the effectiveness of operational scenario and integrated prevention of disaster management system

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.2
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• pp.150-157
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• 2012

This paper presents CAN-based parallel-operation and load-sharing techniques for the communication server power supply. With the load information obtained through CAN communication, each modules performs its current control independently and the power unbalance caused by impedance differences of converter modules can be reduced. In conventional method, slave modules are controlled by master module. On the other hand, the proposed load share algorithm uses the Multi-Master method. Therefore, accurate load sharing can be accomplished by the reference structure of each module's average current. Each converter has two stages and it is separated into PFC, which is responsible for harmonic regulation, and LLC resonant converter, which controls output voltage. To verified the performance of the proposed method, two 2KW prototypes has been implemented and experimented.

• Journal of Internet Computing and Services
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• v.4 no.1
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• pp.67-74
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• 2003

According to change of software development technique as design pattern, component based development etc.., web server development part is applied activity to fit in various user requirement. Especially, EJB as sewer side component model much researches and introduce by easy and various development support. Also, component composing techniques is receiving many interests by easy and efficient application way that architecture based C2 style architecture with message handling. But, in case of EJB component that can not cail thread, C2 framework modification is unavoidable for component composition by C2 style architeccture. For this, we propose techniques to use Adapter pattern to be one of structure pattern among pattern. That is, did so that component composition by C2 style architecture may can consist changing to be able to call thread function in EJB by Adapter pattern.

• The Journal of Korean Association of Computer Education
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• v.3 no.1
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• pp.135-142
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• 2000

Recently the user of distance education system using Intemet-Web are increasing rapidly. This paper shows that Hierarchical WBI documents generator by using CGI is devised and applied to development of distance education system for group-level spoken english. This overcomes the problems of the ready-made programs, which took a lot of time and cost. To generate WBI documents, The key is established to each document saved in server by types of the hierarchical structure and is transmitted to client. By client transmitting this key to server when next documentary is required. Sever can know what documents the client needs. The WBI documentary generator tells the keys transmitted from the client, automatically generates a new documentary to send, and delivery it.

• Journal of Power Electronics
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• v.14 no.5
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• pp.1069-1078
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• 2014

This study presents the design and implementation of a web-based remote laboratory for a multi-mode single-leg power converter, which is a topic in advanced power electronics course. The proposed laboratory includes an experimental test rig with a multi-mode single-leg power converter and its driver circuits, a measurement board, a control platform, and a LabVIEW-based user interface program that is operated in the server computer. Given that the proposed web-based remote laboratory is based on client/server architecture, the experimental test rig can be controlled by a client computer with Internet connection and a standard web browser. Although the multi-mode single-leg power converter can work at four different modes (main boost, buck-boost, boost-boost, and battery boost modes), only the buck-boost mode is used in the experiment because of page limit. Users can choose the control structure, control parameters, and reference values, as well as obtain graphical results from the user interface software. Consequently, the feedbacks received from students who conducted remote laboratory studies indicate that the proposed laboratory is a useful tool for both remote and traditional education.