• Journal of KIISE:Information Networking
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• v.32 no.1
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• pp.60-67
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• 2005

A cluster consists of a collection of interconnected stand-alone computers working together and provides a high-availability solution in application area such as web services or information systems. Content-based load distribution for web server clusters uses the detailed data found in the application layer to intelligently route user requests among web servers. In this paper, we propose a content-based load distribution algorithm that considers cache hit and load information of the web servers under the web server clusters. In addition, we expand this algorithm in order to manage user requests for dynamic file. Specially, our algorithm does not keep track of any frequency of access information or try to model the contents of the caches of the web servers.

• The KIPS Transactions:PartA
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• v.8A no.1
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• pp.70-74
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• 2001

A general web-based remote lecture system uses video data and audio data to provide synchronize between teacher and students. This system requires high bandwidth, high speed networking, television, compression and computing technologies between server and client for remote lecture over Internet. As a result, this system can decrease an efficiency for lecturing over current Internet. So, this paper proposes a new mechanism calling as ‘Synchronization of WWW browsers between server and client’to cope with above problems and finally pursues low cost needed for real-time remote lecture over Internet. The mechanism means that every browser of teacher and students displays the same page and the action of teacher is transferred to the browser of student. And, this can be implemented by Windows hooking APIs, Memory Mapping, and DLL (Dynamic Link Library) programming technology. This paper points to the design and implementation of LAS (Lecture Assistant Server) and LAC (Lecture Assistant Client) to perform the synchronization between server and client.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5669-5684
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• 2018

The new mobile edge network architecture has been required for an increasing amount of traffic, quality requirements, advanced driver assistance system for autonomous driving and new cloud computing demands on highway. This article proposes a hierarchical cloud computing architecture to enhance performance by using adaptive data load distribution for buses that play the role of edge computing server. A vehicular dynamic cloud is based on wireless architecture including Wireless Local Area Network and Long Term Evolution Advanced communication is used for data transmission between moving buses and cars. The main advantages of the proposed architecture include both a reduction of data loading for top layer cloud server and effective data distribution on traffic jam highway where moving vehicles require video on demand (VOD) services from server. Through the description of real environment based on NS-2 network simulation, we conducted experiments to validate the proposed new architecture. Moreover, we show the feasibility and effectiveness for the connected car media service on highway.

• The Transactions of the Korea Information Processing Society
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• v.6 no.1
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• pp.57-65
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• 1999

The simulation which is larger scale, complex and interactive with clients treat a lot of messages. It can be thinking more efficient distributed simulation than sequential one. The training simulation with multi-users is geographically distributed, and required high cost to operate and maintain system as increasing user requirements. The adaptation of web technology to the simulation can be a way to solves it without cost added. But dynamic web environment can causes causality error of events. This paper is concerned with client-server model, which supports interaction between distributed simulation server and web browser, and it is implemented by Java distributed object model. the result have shown that the distributed simulation is performed correctly on dynamic environment.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.3
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• pp.61-72
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• 2009

To guarantee security between the tag and back-end server and implementation efficiency in low power tag, we propose two typed mutual authentication protocols in RFID system. One is static-ID authentication scheme which is well suitable in distributed server environments. The other is dynamic-ID scheme which is additively satisfied forward security. In proposed scheme, it does not need any random number generator in tag and requires only one(maximally three) hash operation(s) in tag or server to authenticate each other. Furthermore, we implement the proposed schemes in RFID smart card system and verify its normal operations.

• The KIPS Transactions:PartA
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• v.10A no.6
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• pp.677-684
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• 2003

Most policies of VOD services are mainly studied about server system, and make no touch on clients buffer stabilization which is the basis of guaranteeing playback quality and playing without cut off. In this paper, we proposed a skipping frame transfer policy that can sending dynamic buffer control signal to server in accordance with clients buffer state of starvation or overrun, and server transfers a skipped frame to client after receive the control signal. And through a simulation, we show the suggested policy is more efficiency on playback quality by buffer stabilization which is by preventing loss and miss for receiving frame due to grow worse client buffer state.

• Journal of Internet Computing and Services
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• v.7 no.6
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• pp.11-20
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• 2006

One of the most important factor while developing web application is to separate presentation and business logic lowering the maintenance cost. There are various web application development tools mainly categorized as script based such as Servlet, JSP, ASP.NET techniques and dynamic server page development frameworks such as Struts, JSF (Java Server Faces), Spring MVC etc. These tools provide web tier processing solution but not the complete separation of presentation and business logic. In this paper, we developed custom tog component that separate presentation and business logic, to process them we also developed container. In addition, DOM tree is applied to the developed container to manage the presentation effectively.

• Journal of KIISE:Computing Practices and Letters
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• v.12 no.4
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• pp.264-274
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• 2006

Recently, a variety of organizations including enterprises tend to try to use reporting tools as a data analysis tool for decision making support because reporting tools are capable of formatting data flexibly. Traditional reporting tools have thin-client structure in which all of dynamic documents are generated in the server side. This structure enables reporting tools to avoid repetitive process to generate dynamic documents, when many clients intend to access the same dynamic document. However, generating dynamic documents for data analysis doesn't consider a number of potential readers and increases requests to the server by making clients input various parameters at short intervals. In the structure of the traditional reporting tools, the increase of these requests leads to the increase of processing load in the server side. Thus, we present the reporting tool that can generate dynamic documents at the client side. This reporting tool has a processing mechanism to deal with a number of data despite the limited memory capacity of the client side.

• Journal of the Korean Data and Information Science Society
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• v.25 no.1
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• pp.27-36
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• 2014

Statistical analysis provides information that can be applied to draw final decisions in many fields. However, statistical analysis program for PC (personal computer) is yet restricted by time and space. To minimize this issue, a server based PC statistic analysis program using internet in addition to web based system allowing statistical analysis have been continually developed. However, the current web based analysis system is limited to the data that is saved on the server. Data that is modified or newly inserted must go through a server administrator before its use in analysis. In order to solve this problem, we have developed a web based system using HTML, java, JSP scripts to incorporate dynamic data without much restriction.

• Journal of the Korea Society of Computer and Information
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• v.3 no.3
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• pp.23-30
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• 1998

The ODBC(Open Database Connectivity) is particularly efficient in the dynamic client/server environment. Besides, the ODBC provides the functions that can handle multimedia data. Due to this feature, we are able to use the DBMS that supports the ODBC as a multimedia server. In this thesis, we describe the development of the ODBC driver for Relational DBMS. The Relational DBMS ODBC Driver consists of the client module and the server module. The client module is called the SRM(Server Request Module) and the server module is CSM(Client Service Module). These two modules are connected through the network module called the NSM(Network Service Module). We have conducted both the functional and the interoperability test of our ODBC Driver It turned out that the ODBC driver operated with these client DBMS tools successfully. In all, due to our development of the Relational DBMS ODBC Driver, DBMS is now capable of processing multimedia data and supporting the client applications including the DBMS tools.