• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.49-52
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• 2001

In this paper, the design and implementation of the Geographic Information Retrieval System for the ArcView is described. The environments for the system configurations include a PC server under Linux Operating System, Apache Web-server, and Oracle as database engine. In addition, JSP(Java Server page) and Servlet is used to view database and Map-Image.

• The Journal of Information Systems
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• v.4
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• pp.85-104
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• 1995

In a loosely-coupled distributed database server system, a server failure and/or a communication failure can be masked by a resiliency mechanism. Recognizing that a distributed transaction executes at several servers during its lifetime, we propose a resiliency mechanism which allows continuous transaction processing in distributed database server systems in the presence of a server failure. The resiliency mechanism for transaction processing is achieved by keeping redundant information using a primary/backup approach. The purpose of this paper is to analyze the performance improvement opportunities with the resiliency mechanism and to present the design of the proposed system.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.751-753
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• 2004

PDA에서 사용하는 대부분의 CPU는 실수 연산 구성요소(float computation component)가 없는 정수(integer) CPU를 사용한다. 인공 신경망(neural network)과 같은 실수 연산이 많은 알고리즘은 PDA에서 많은 수행시간을 가진다. 본 논문에서는 이런 단점을 해결하기 위해 무선 랜(LAN)으로 연결된 Client(PDA)/Server(PC) 구조를 이용한 효과적인 문자 추출 시스템을 제안한다. Client(PDA)는 대략적인 문자 추출 결과를 JPEG으로 압축하여 전송속도를 최소화한다. Server(PC)는 Client(PDA)의 결과를 바탕으로 정밀한 문자 영역 추출을 위해, 텍스춰 분류 방법과 연결 성분 분석 방법을 이용한다. 실험에서 제안한 방법은 속도뿐만 아니라 문자 추출에서도 효과적이었다.

• The KIPS Transactions:PartC
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• v.9C no.4
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• pp.605-614
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• 2002

Amount of the web traffic web server handles are explosively increasing, which requires that the performance of the web server should be improved for the various web services. Although the analysis for the HTTP traffic with the proper tuning for the web server is essential, the research relevant to the subject are insignificant. In particular, although most of applications are implemented over HTTP 1.1 protocol, the researches mostly deal with the performance evaluation of the HTTP 1.0 protocol. Consequently, the modeling approach and the performance evaluation over HTTP 1.1 protocol have not been well formed. Therefore, basing on the HTTP 1.1 protocol supporting persistent connection, we present an analytical end-to-end tandem queueing model for web server to consider the specific hardware configuration inside web server beginning at accepting the user request until completing the service. we compare various performances between HTTP 1.0 and HTTP 1.1 under the overloading condition, and then analyze the characteristics of the HTTP traffic that include file size requested to web server, the OFF time between file transfers, the frequency of requests, and the temporal locality of requests. Presented model is verified through the comparing the server throughput according to varying requests rate with the real web server. Thereafter, we analyze the performance evaluation of the web server, according to the interrelation between TCP Listen queue size, the number of HTTP threads and the size of the network buffers.

• Journal of the Korean Society of Systems Engineering
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• v.15 no.2
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• pp.66-71
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• 2019

In digital pathology, an electronic system in the biomedical domain storage of the files is a big constrain and because all the analysis and annotation takes place at every user-end manually, it becomes even harder to manage the data that is being shared inside an enterprise. Therefore, we need such a storage system which is not only big enough to store all the data but also manage it and making communication of that data much easier without losing its true from. A virtual server setup is one of those techniques which can solve this issue. We set a main server which is the main storage for all the virtual machines(that are being used at user-end) and that main server is controlled through a hypervisor so that if we want to make changes in storage overall or the main server in itself, it could be reached remotely from anywhere by just using the server's IP address. The server in our case includes XML-RPC based API which are transmitted between computers using HTTP protocol. JAVA API connects to HTTP/HTTPS protocol through JAVA Runtime Environment and exists on top of other SDK web services for the productivity boost of the running application. To manage the server easily, we use Tkinter library to develop the GUI and pmw magawidgets library which is also utilized through Tkinter. For managing, monitoring and performing operations on virtual machines, we use Python binding to XML-RPC based API. After all these settings, we approach to make the system user friendly by making GUI of the main server. Using that GUI, user can perform administrative functions like restart, suspend or resume a virtual machine. They can also logon to the slave host of the pool in case of emergency and if needed, they can also filter virtual machine by the host. Network monitoring can be performed on multiple virtual machines at same time in order to detect any loss of network connectivity.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.4
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• pp.25-40
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• 2012

This paper suggests the way to build the integration of internal server by using link server with virtualization method. With the development of on-line games, game communities began to be formed by users, players get fun from playing games, sharing online space with friends, clans, and parties. However, the limit of physical server restrict the allows under average a hundred users to play at same time and place, and three thousand to ten thousand people to access to game community with chat, message, friends functions. By following the explanation of the method from this paper, this limit can be overcome. It will give the function to share information of all connected users in one displayed server. This paper demonstrates the key quality requirements of the server built by this way such as scalable architecture, consistency, and latency is fulfilled.

• Journal of Information Technology Services
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• v.10 no.4
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• pp.281-293
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• 2011

Server consolidation and virtualization have become an integral part of IT planning to reduce TCO cost and ensure the high availability for customer, enlarge the flexibility to computing resource in today' enterprise data centers. In spite of having the variety advantages of server consolidation and virtualization, they cause many problems such as the software licensing issues, virtual server sprawl, network complexity issues, hardware start-up costs, and failover costs. In particular, software licensing problem brings about the serious results in operating of data center and also presents a significant challenge to virtualization because many vendors have realized that licensing policies applicable to physical systems are not compatible with virtual machines. So, the IT planers must be considering this problem before they conducts the server consolidation and virtualization. In this paper, we proposed the efficiency strategy of SW licensing for server consolidation and virtualization analyzing the N-Datacenter case in Korea. As a result, we suggest the two strategies as technical and management/contract aspect. First, as the technical aspect, we propose i) the adaptation of suitable licensing for virtualization, ii) differentiation of license according to the characteristics of server, iii) the core distribution of licenses to minimizing. Second, as the management/contract aspect, we suggest following three things. i) The existing license agreement is changed to the right licensing for virtualization. ii) The license agreement is contracts the active focused. iii) When a new contract should be added to virtualization provisions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.9
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• pp.2105-2112
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• 2013

In this paper we implemented a web-based performance monitoring system for web mail server. For this system we derived performance monitoring items and fixed its threshold values for each measuring items. We used the SCOM 2007 server monitoring tool for collecting the performance data of web mail server and Exchange server management pack and server monitoring rules of SCOM 2007 to set the performance analysis parameters. We implemented this performance monitoring system using C# programming based on the ASP.NET framework. This system supports web-based performance report, failure report and resource availability report from the performance analysis results. Therefore the manager can easily detect the failures of web mail server in advance and decrease the number of failure over 60%. Also this system helps manager to minimize the recovery time when the failure occurs.

• Journal of the Korea Computer Industry Society
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• v.5 no.3
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• pp.345-354
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• 2004

In these days, such services are popularized as E-commerce, E-government, multimedia services, and home networking applications. Most web traffics generated contemporarily basically use the Hyper Text Transfer Protocol(HTTP). Unfortunately, the HTTP is improper for these applications that comprise significant components of the web traffics. In this paper, we introduce a real-time contents compression architecture that maximizes the web service performance as well as reduces the response time. This architecture is built into the linux kernel-based web accelerating module. It guarantees not only the freshness of compressed contents but also the minimum time delay using an server-state adaptive algorithm, which can determine whether the server sends the compressed message considering the consumption of server resources when heavy requests reach the web server Also, We minimize the CPU overhead of the web server by exclusively implementing the compression kernel-thread. The testing results validates that this architecture saves the bandwidth of the web server and that elapsed time improvement is dramatic.

• Journal of Advanced Navigation Technology
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• v.17 no.4
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• pp.421-428
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• 2013

Voice over IP refers to technology that enables routing of voice conversations over the Internet or a TCP/IP network. VoIP communication costs cheaper than traditional analog phone. Phone calls can be made to anywhere / anyone: Both to VoIP numbers as well as people with normal phone numbers. VoIP protocol equipment available today follows the SIP standard. Older VoIP equipment though would follow H 323, MGCP, Megaco/H.248. A SIP server is the main component of an IP PBX, dealing with the setup of all SIP calls in the TCP/IP network. A SIP server is also referred to a Asterisk IP-PBX. A VoIP telephone, also known as a SIP phone or a softphone, allows the user to make phone calls to any softphone, mobile or PC by using App store. A VoIP telephone can be a simple software-based softphone. However, the SIP Server and the program is vulnerable to VoIP attacks. In this paper, eavesdropping attacks tested by using the Asterisk SIP server. Eavesdropping attacks and TLS security methods apply to VoIP system. TLS can be applied to determine whether the eavesdropping available for VoIP Environments.