• Information Systems Review
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• v.11 no.1
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• pp.161-179
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• 2009

Nowadays an increasing number of Internet users are running individual websites as Blog or Cyworld. As this type of personal media has a great influence on communication among people, business comes to care about Network Effect, Network Software, and Social Network. For instance, Cyworld created the web service called 'Minihompy' for individual web-logs, and acquired 2.4milion users in 2007. Although many people assumed that the popularity of Minihompy, or Blog would be a passing fad, Cyworld has improved its service, and expanded its Network with various contents. This kind of expansion reflects survival efforts from infinite competitions among ISPs (Internet Service Provider) with focus on enhancing usability to users. However, Cyworld's Network Effect is gradually diminished in these days. Both of low production cost of service vendors and the low searching/conversing costs of users combine to make ISPs hard to keep their market share sustainable. To overcome this lackluster trend, Cyworld has adopted new strategies and try to lock their users in their service. Various efforts to improve the continuance and expansion of Network effect remain unclear and uncertain. If we understand beforehand how a service would improve Network effect, and which service could bring more effect, ISPs can get substantial help in launching their new business strategy. Regardless many diverse ideas to increase their user's duration online ISPs cannot guarantee 'how the new service strategies will end up in profitability. Therefore, this research studies about Network effect of Cyworld's 'Minihompy' using System-Dynamics method which could analyze dynamic relation between users and ISPs. Furthermore, the research aims to predict changes of Network Effect based on the strategy of new service. 'Page View' and 'Duration Time' can be enhanced for the short tenn because they enhance the service functionality. However, these services cannot increase the Network in the long-run. Limitations of this research include that we predict the future merely based on the limited data. We also limit the independent variables over Network Effect only to the following two issues: Increasing the number of users and increasing the Service Functionality. Despite of some limitations, this study perhaps gives some insights to the policy makers or others facing the stiff competition in the network business.

• Journal of KIISE:Information Networking
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• v.34 no.4
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• pp.296-304
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• 2007

This paper deals with essentially secure group management and key transfer methods in a wireless sensor network environment. To provide an efficient security service to a widespread network with a large number of sensor nodes, the network has to be made up by several security groups, and Group Key distribution and group management are needed. In this paper we propose a mechanism for efficiently constructing and managing a security node by constructing a group using an algorithm to construct a logical group. Previous Group Key Transport method has special condition. When Base Station transports Group Key, all sensor nodes must share Secret Key with Base Station before it is intended to be deployed. Hence, we also propose a Key transport mechanism without sharing Secret Key between Base Station and sensor node.

• Journal of Advanced Navigation Technology
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• v.15 no.4
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• pp.664-671
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• 2011

The development of IT technology and breakthrough of the network and the wired network, wireless network boundaries disappear and wired and wireless integrated service environment is the advent in online game environment. However, the wired and wireless integrated service environment appropriate security technology is still inactive, wired and wireless integration environment due to the characteristic as well as security threats wired network and security threats in wireless networks should be considered. Therefore, This wired and wireless integrated environment has been considering studied various, Among them wired and wireless environment considering the lightweight of ID-based authentication and key management has been in progress. In recent, Moon et al. pervasive environment in authentication and ID-based key management protocol is proposed. However, Moon et al.'s scheme is use the ID-based public-key approach to decreased the amount of computation. However, pairing by using a technique similar to the existing public key scheme can represent the amount of computation. Therefore, In this paper the way of Moon etc in security vulnerability analysis.

• Journal of the Korean Society for information Management
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• v.27 no.2
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• pp.61-74
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• 2010

The knowledge sharing in a knowledge management process is much affecting generation and distribution of knowledge. Especially, the knowledge distribution is being revitalized with the center of social media service like twitter and library service 2.0 in the knowledge-based IT (Information Technology) environment. The present research analyzed the structure and characteristics of a social network inside an organization that is growing like an organism through self-organization through tools for SNA (Social Network Analysis) and multiple regression analysis of independent variables such as 1) a relationship between social network's structure and knowledge sharing, 2) a relationship between structural holes and knowledge sharing influence of centrality, 3) a relationship between individual ability and knowledge sharing of information technology and work recognition.

• Electronics and Telecommunications Trends
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• v.16 no.5 s.71
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• pp.33-45
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• 2001

원활한 인터넷 서비스를 제공하기 위해서는 인터넷 트래픽을 효율적으로 관리할 수 있어야 하며, 이를 위해 가장 먼저 해야 할 것은 인터넷 트래픽을 측정하는 것이다. 인터넷 트래픽의 측정은 수동적인 측정과 능동적인 측정으로 분류된다. 수동적인 측정은 라우터나 ATM 스위치를 통해 흘러 다니는 트래픽 종류와 트래픽 양을 측정하여 측정네트워크의 트래픽 특성을 파악하는 것이고, 능동적인 측정은 측정네트워크 종단에 위치한 두 호스트 사이에 측정패킷을 투입하여 측정네트워크의 상태를 파악하는 것이다. 본 고는 현재 알려진 인터넷 트래픽 측정 방법과 현재 구현된 측정 시스템을 소개한다.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.3
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• pp.303-308
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• 2016

Recently, as the rapid development of network technology and the increase of services required high bandwidth such as multimedia service, the network traffic dramatically increases. This massive increase of network traffic causes some problems such as the degradation of QoS and the lack of network resources and, to solve these problems, various research to guarantee QoS have been performing. Currently, The most representative method to guarantee the QoS is the DiffServ(: Differentiated Service). The DiffServ defines the AF(: Assured Forwarding) PHB(: Per Hop Behavior) and statistically ensures the throughput over the certain level of data rate. However, the TCP congestion control method that make up the majority of the Internet traffic is not fundamentally suitable to the DiffServ that guarantees the throughput without managing the individual flow. Therefore, in this paper, we present this mismatch through the simulation as an example and propose the solution by controlling the TCP of the terminal in the network. The proposed scheme utilizes the information of the reception window size included in the ACK frame and does not require any modification of the TCP algorithms currently in use.

• Journal of Korean Society of Transportation
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• v.27 no.1
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• pp.191-200
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• 2009

This study develops composite indicators that is capable of estimating QOS (Quality of Service) of pedestrians by enhancing estimation for Level of Service in present transporting spaces for pedestrians that merely concerns quantitative indicators such as pedestrian flow rate, pedestrian stoppage. This paper conducts survey questionnaire to collect data. It utilizes AHP(Analytic Hierarchy Process) and ANP(Analytic Network Process). The main results show that: first, ANP is better analytic methods than AHP due to the fact that pedestrians feel repetition when they judge level of service. Second, qualitative factors such as pedestrian behaviors, maintenance, scenary for pedestrians and environments should be considered. Importance of qualitative factors is higher in residential area than other areas. I expect that using qualitative indicators and quantitative indicators is appropriate in order to estimate pedestrians' QOS.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.26 no.1
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• pp.279-302
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• 2015

The purpose of this study is to analyze researchers' information use behaviors in the field of business administration in order to provide library services based on user information needs. The methods of this study targeted the members of K Society in the business administration field, and employed user survey using a web-based questionnaire. A total of 202 users answered the questionnaire. The questionnaire focused on items such as by age and status, general information use, electronic resources use, SNS and mobile services information use, library and information center use, and specialized business administration library use. The results of this study suggested improving several library services.

• Annual Conference of KIPS
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• 2002.11a
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• pp.131-134
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• 2002

초고속 네트워크에 연동된 고성능 컴퓨터 자원들을 효과적으로 활용하려는 그리드 컴퓨팅 연구는 네트워크를 통한 기존의 단순한 정보 공유보다 정보 및 자원의 공유를 더욱 더 밀접하게 결합시키는 것을 가능하게 한다. 이상적인 그리드 컴퓨팅 환경을 구축하기 위해서는 무엇보다도 그리드 환경에 속한 자원들의 정보를 통합적으로 관리 및 서비스하는 것이 무엇보다도 그리드 정보 서비스가 중요하다. 그리드 정보서비스의 역할은 그리드 사용자가 필요한 자원 및 그에 대한 정보를 쉽게 찾을 수 있도록 다양한 검색 기능을 제공하는 것 이외에도, 전세계에 분산된 자원들의 최신 정보를 빠르게 서비스하도록 하여야 한다. 이를 위해서는 그리드 환경의 특성을 고려하여 효율적인 그리드 정보 서비스 아키텍쳐를 구성하는 것이 필요하다. 본 논문에서는 그리드 미들웨어인 글로버스 툴킷(Globus $Toolkit^{TM}$)내에 포함된 그리드 정보 서비스를 기반으로 자원 정보의 적응형 캐슁 기법을 이용하여 그리드 정보 서비스 아키텍쳐를 재구성한다. 이를 통해 자원 정보의 일관성을 향상시키면서 기존의 그리드 정보 서비스의 빠른 응답 속도를 제공할 수 있다.

• 한국공간정보시스템학회:학술대회논문집
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• 2005.11a
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• pp.47-54
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• 2005

정보 사회가 발전하고 정보의 활용이 늘어남에 따라 공간 데이타가 다양한 분야에서 활용되고 있다. 그리고, 공간 데이타가 널리 활용됨에 따라 ESRI와 같은 다양한 지리 정보 시스템(Geography Information System)이 발전하게 되었다. 그러나, 기존의 지리 정보 시스템은 다양한 분야에서의 활용을 위해 많은 기능을 제공함으로 인해 일반적으로 대용량 공간 데이타에 대한 검색이 비효율적이다. 특히, 네트워크 환경이 발전하고 컴퓨팅 파워가 증가함에 따라 점차 대용량의 지도 서비스를 제공하는 분야에서 기존의 지리 정보 시스템 적용 시공간 데이타 검색 속도가 저하되는 문제가 발생한다. 따라서, 본 논문에서는 안정적인 상용 DBMS인 Oracle을 기반으로 대용량 공간 데이터를 효율적으로 검색할 수 있는 Oracle 기반의 대용량 지도 서비스를 위한 XServer를 설계 및 개발하였다. XServer는 다양한 클라이언트의 질의를 효율적으로 처리하기 위한 질의 처리 관리자, 대용량의 공간 데이타를 빠르게 검색하기 위한 공간 인덱스 관리자 및 데이타 버퍼 관리자, 대용량의 공간 데이타를 안정적으로 저장하기 위해서 Shape 화일에서 추출한 공간 데이타를 Oracle에 저장 및 관리하기 위한 수입/수출 관리자와 DB 관리자로 구성되어있다. 마지막으로, 본 연구에서 개발한 Oracle 기반의 대용량 지도 서비스를 위한 XServer와 Oracle Spatial을 비교함으로써 기능을 검증하고 성능의 우수함을 입증하였다.