• Information Systems Review
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• v.1 no.1
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• pp.35-49
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• 1999

• Proceedings of the KIEE Conference
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• 2000.11d
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• pp.815-817
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• 2000

근래 Web Server의 안정된 운용의 중요성이 급증하는 Network Traffic과 더불어 점차 증대되고 있다. 기본적인 Network 구성망은 Ethernet으로 표준적인 프로토콜은 TCP/IP로 기반을 잡고 있다. 날로 증가하는 Network Traffic을 효과적으로 처리하기 위해서는 Network의 bandwidth 및 서버가 처리할 수 있는 데이터 양을 분석하여 병목현상을 줄이고 데이터의 흐름을 원활히 하기 위한 데이터 buffer들의 설치와 적절한 운영 방법에 관한 연구가 필요하다. 본 논문에서는 Web Server로부터 image 데이터를 전송 받아 이를 원활히 display하기 위한 Application Layer에서의 buffer 크기 및 제어방법에 관한 연구를 수행하고 특히 연속적인 이미지의 전송과 재생에 관한 buffer management에 관하여 고찰한다.

• Journal of the Korea Society of Computer and Information
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• v.21 no.10
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• pp.69-76
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• 2016

In this paper, we propose a real-time remote logging model for development of android applications using LBS(Location based Service). The model has two major parts: Mobile Log Management Service and Remote Log Server. Mobile Log Management Service consists of the log collector and the remote log manager. The log collector is an aspect of AOP which can collect logs from the target application without modifications of source codes. The remote log manager has a background service component so that it can receive logs whenever the log collector captures logs from the target application. Remote Log Server communicates with Mobile Log Management Service by socket interface. Therefore, Remote Log Server can show logs in real-time. To validate the efficiency of the proposed model, we show a case study, and compare the model with other models.

• Publications of The Korean Astronomical Society
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• v.26 no.4
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• pp.159-168
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• 2011

We constructed two test server systems for KMTNet data management. One is the photometry database server which is optimized for stable operation, and the other is the photometric data process server which is optimized for fast I/O between devices. The performances of servers and data storage units were tested using various methods. Database upload was also checked using five different methods. From tests, we concluded that the most efficient method to upload photometric data processing results to database is the use of three nodes with job scheduler under the InnoDB engine. In this study we provide the test results for prototype servers for KMTNet data management.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.3
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• pp.171-179
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• 2014

Among the P2P based multimedia streaming architecture, multiple chain architecture has advantage in adapting to dynamically changing network topology simply and rapidly, so this architecture is used for UCC broadcasting system. In UCC broadcasting system, general peer involved in DSLAM becomes UCC server rather than broadcasting system that transfers data from ISP servers. Therefore UCC data generated from UCC server peers is transmitted to peers through DSLAM, and this transmission uses uplink bandwidth of DSLAM. In this paper, I propose an efficient management method of DSLAM uplink bandwidths through negotiating tracker and UCC server peer or head peers of DSLAM. I propose the method that tracker restricts a bitrate of uplink stream of UCC servers when used uplink bandwidth of DSLAM exceeds a certain point of maximum uplink bandwidths. I will show the improved performance of proposed scheme rather than general method with respect to the uplink bandwidth of DSLAM by numerical analysis and simulation.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.651-652
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• 2009

온라인에서의 전자 거래가 활성화됨에 따라 생활의 편의성은 높아진 반면에 개인 정보 유출의 위험은 점점 증가하고 있다. OTP(One Time Password)는 고정된 패스워드 사용의 문제점을 보완한 강력한 보안 메커니즘이다. 웹 기반의 어플리케이션 탑재가 가능한 SCWS(Smart Card Web Server)에 OTP 기술의 적용은 보안관점에서 더욱 효과적인 결과를 유도할 수 있다. 본 논문은 차세대 스마트카드의 주요 기능 중 하나인 SCWS에 대해 연구하고 OTP 기술을 탑재하여 사용자 중심의 편의성 증진과 안전성을 강화하는 방법을 모색한다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.3
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• pp.469-476
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• 2016

Relational Database Management Systems have become de facto database model among most developers and users since the inception of Data Science. From IoT devices, sensors, social media and other sources, data is generated in structured, semi-structured and unstructured formats, in huge volumes, thereby the difficulty of data management greatly increases. Organizations that collect large amounts of data are increasingly turning to non relational databases - NoSQL databases. In this paper, through experiments with real field data, we demonstrate that MongoDB, a document-based NoSQL database, is a better alternative for building a Telco Subscriber Data Management System which hitherto is mainly built with Relational Database Management Systems. We compare the existing system in various phases of data flow with our proposed system powered by MongoDB. We show how various workloads at some phases of the existing system were either completely removed or significantly simplified on the new system. Based on experiment results, using MongoDB for managing telco subscriber data turned out to offer performance better than the existing system built with MSSQL Server.

• Journal of the Korea Convergence Society
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• v.9 no.10
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• pp.69-74
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• 2018

IP and SIP public broadcasting systems developed in Korea and abroad are developed in a Windows or Linux server environments and are installed in a server-rack structure, have high power consumption, and are difficult to remotely respond to system failures. In this paper, IoT platform is designed to connect IoT device and gateway to IoT service server by using internet service structure. We also designed a server based on embedded OS that can provide a variety of public safety management services according to the order of the server with built-in call processing and broadcasting function that can handle emergency calls and emergency broadcasts in public places using this structure. This server is interoperable with a variety of SIP-based call and broadcast devices that support the standard SIP and can be integrated with an in-house phone and on-premises system.

• Journal of KIISE:Information Networking
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• v.29 no.3
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• pp.265-275
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• 2002

A default server strategy is a very popular scheme for managing location and state information of mobile hosts in cellular networks. But the communication cost increases if the call requests are frequent and the distant between the default server and the client is long. Still more any connection to a mobile host cannot be established when the default server of the destination mobile host fails. These problems can be solved by replicating default server and by letting nearest replicated default server process the query request which is sent from a client. It is important to allocate replicated default servers efficiently in networks and determine the number of replicated default servers. In this paper, we suggest and evaluate a default server replication strategy to reduce communication costs and to improve service availabilities. Furthermore we propose and evaluate an optimized allocation algorithm and an optimal replication degree for replicating: dofault servers in nn grid networks and binary tree networks.

• The KIPS Transactions:PartD
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• v.8D no.5
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• pp.605-612
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• 2001

In order to solve the overload of academic affairs management system, we propose a method builds a distributed Replication server and uses this server with the present centralized system. Normal query transactions which are not required for data modification are composed of almost all DML sentences. So we construct the distributed replication servers according to the data characteristics and make them perform the query transaction without modification. In this way, we can simultaneously distribute users and data, and cut down processing time for every transaction. Also Replication server has the advantages of implemental efficiency and economical because it uses resources of present centralized system without and additional configurations. Usually, to distribute the overload of server, they can use way, Client-side overload distribution that user program get present overload status then can choose a less overloaded server, and the other way, Server-side overload distribution that make use of Application Layer Scheduling Technique and IP Layer Scheduling Technique. Our Replication server can reduce the overload of centralized system by eliminating or complementing those defects of overload distribution, referred to in the forehead.