• The KIPS Transactions:PartC
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• v.15C no.5
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• pp.343-350
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• 2008

In ubiquitous environment, a user has been provided with service and mobility using various devices. The users' network can be divided into a home network (a user belongs to the network through an authentication server) and an external network (when a user moves or external authentication server is). Users can use a mobile device or a device at an external network. In this paper, when a user has access to a service in an external network with a mobile device, there is a skim that a service is securely provided by roaming private information (encryption key etc${\cdots}$) and a skim which gives access to a home network using a device in an external network. If you use these skims, roaming is provided in order that you can use a secure service in an external network.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.405-409
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• 2008

우리나라의 도시는 리우선언이후 지속가능한 개발 원칙아래 친수와 생태를 모티브로 하여 급격히 변화되어 개발되어 가고 있다. 파주운정신도시는 국내최초 물순환시스템, 광교신도시는 2개의 기존 저류지를 활용한 물순환시스템, 인천청라지구는 녹지공간에 운하를 만드는 운하도시, 김포신도시는 대수로를 활용한 운하도시, 강서지구는 한강과 연결되는 친수도시로 진행중이다. 이러한 개발에는 지속가능한 수량확보와 수질보전이 선결되어야 하므로 다양한 방안들이 제시되고 있으며, 이에 따라 물을 다스릴 수 있는 도시로 변화함에 따라 치수적으로 안전할 뿐 만 아니라, 각종 재난으로 부터도 안전한 U-city로 진행되고 있다. 국외의 경우 미국의 샌안토니오 등이 도시내 운하를 건설하여 관광객을 유치하고 있고, 독일의 크론스베르크가 지구 전체에 우수저류 및 침투시설을 도입하였으며, 일본 동경이 새로운 운하프로젝트를 수행중이다. 또한 홍콩이 세계최대의 습지공원을 신도시와 병행하여 건설하였고, 싱가폴에서는 아시아 최대의 담수화 공장을 건설중이며, 뉴워터(Newater) 프로젝트로 물을 재사용하고 있다. 이러한 국내 외 사례가 물순환시스템을 체제를 구축하기 위한 기초자료를 제공할 수 있으리라 판단된다. 본 연구에서는 이러한 물순환시스템의 전체적인 개념을 다양한 선진사례 등을 토대로 검토하고, 현재 진행중인 국내 도시들을 토대로 정리하여, 물순환시스템의 체제를 구축하는 방안을 제시하고자 한다. 본연구를 통해 향후 국내 지자체들의 도시재개발과 신도시개발, 국외 도시개발시 물순환시스템을 구축하는 경우 물순환과 관련된 기초자료로 활용할 수 있으리라 판단된다.

• Journal of Korean Society for Geospatial Information Science
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• v.25 no.2
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• pp.39-47
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• 2017

Although motorcycle safety studies to date have identified the causes of motorcycle accidents in general, very few have investigated postal motorcycle accidents by studying the delivery postmen's specific work environment. To better understand postal motorcyclists' driving behavior associated with their delivery workload, we developed a system using V-World platform which visualizes driving behavior in real time along the driver's delivery route throughout an entire work day. We conducted a field test to examine the feasibility of our system by involving six delivery postmen currently working in Songpa, Seocheongju, and Gangseo, respectively. To show the potential of our system for nationwide comparison of postal motorcyclists' driving behavior and their workloads, we present several sample analyses using the collected field data. Although ideally, postmen's workloads should be standardized nationwide, we found large variation depending on regional characteristics of work area which affects postmen's driving behavior.

• Journal of Korea Multimedia Society
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• v.7 no.11
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• pp.1610-1619
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• 2004

While researches and studies on short distance wireless communications have been actively carried out, studies on many applications of short distance wireless communications focusing on user-oriented Mobile device are also in progress. Since Bluetooth has several advantages that existing short distance communication does not have, studies on standardization have been carried out focusing on SIG, and IEEE has also jointly studied on this. Bluetooth is a short distance wireless communication technology that can be usefully applied to various kinds of applications. In this regard, this thesis presents payment system using Bluetooth, out of several application technologies of Bluetooth. This payment system is based on the scenario in which secure piconet is formed focusing on the user, the user gets in the car, fill up the gas at the gas station using his own Mobile device and pay The secure payment system presented in this thesis is designed to complement the weakness of existing Bluetooth in terms of security and to secure several requirements of security required for payment using short distance wireless communication.

• Korean Journal of Soil Science and Fertilizer
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• v.15 no.2
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• pp.95-100
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• 1982

The residual effect of silicate fertilizer (crushed slag from the steel industry) on rice yield was evaluated through 4-year field experiments. Applications of the silicate fertilizer at rate of 2500 kg/ha to Gangseo sandy loam soil (Fluvaquentic Eutrochrepts) very low in available silica increased the grain yield by 7 to 12% depending on the mesh size of the fertilizer in the first year. The yield in the fourth year showed no residual effect. Seventeen to eighteen months after the application, available silica content of the soil (1N-sodium acetate extractable) decreased down to 130 ppm which is a, base level for the silicate fertilizer application. Decreasing tendency of available silica concentration of the soil with time differed according to the mesh size of the silicate fertilizer applied. In 36 to 48 months after the application, the extractable silica content of the soil converged to 90 to 100 ppm.

• Journal of the Korea Society of Computer and Information
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• v.13 no.4
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• pp.59-69
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• 2008

The purpose of this study was to investigate children's Perception of parenting attitude parent and learned helplessness on addictive use of computer game. The data was collected through paper-pencils surveys with 745 students who are attending the 4, 5, and 6 grade of three elementary schools. The instrument used to see how they looked at the parenting attitude of their was Ji-hyun Hwang(2006)'s Perceived Parenting Attitude Inventory, Chang-woo Song(1997)'s Learned Helplessness, and Internet Game Addiction Test by developed Korean Agency Digital Apportunity & Promotion. Statistics and methods used for the data analysis were Cronbach'a alpha, freuency, percentage, Two-Way ANOVA, Pearson's Correlation, and Regression by using SPSS WIN 12.0. The results of this study is described as follows. In this study, prevalence of computer addiction tendency and addiction is 14.3%. Male students showed highest computer addiction game than female students.

• The KIPS Transactions:PartC
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• v.13C no.3 s.106
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• pp.359-368
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• 2006

AAA(Authentication, Authorization, Accounting) is the service that offers authentication, authorization, and accounting method, and every terminal that accesses the network requires this AAA service. The authentication process of a mobile terminal is as follows: a mobile phone accesses an authentication server in a home network via the authentication service in an external network, which receives the authentication result. And, for the home authentication server to offer secure service, a unique key is distributed for the secure communication between the external agent and the user, the external agent and the home authentication server, and the user and the home authentication server. This paper discusses and proposes the key distribution for secure communication among external authentication servers when a mobile terminal travels to an external network. As the proposed method does not require the home authentication server to reissue another authentication when a user travels to other external networks, it reduces the overload in the home authentication server. It can also distribute a PIN-driven key.

• Journal of IKEEE
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• v.7 no.2 s.13
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• pp.223-229
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• 2003

In this thesis, the characteristics of an inverted-F antenna for the 2.4GHz and 5.8GHz zwirless local area network(WLAN) have been analysed in terms of the variation of design parameters. The antenna can be integrated on WLAN for notebook printed circuit board, and the characteristics in terms of the variation of the gap between feed line and shorting stub, gap between antenna's leg and ground plane, antenna leg's width, substrate's height and dielectric constant are analysed. By using these characterization plot of design parameter, the tuning techniques are proposed to design optimum antenna. The designed antenna has 170MHz, 500MHz frequency bandwidth ,VSWR is 1.6, 1.14 and 3.5dBi gain.

• Applied Biological Chemistry
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• v.23 no.4
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• pp.246-250
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• 1980

The effects of two Cytozyme complexes, Crop Plus and Seed Plus, applied to rice (variety: Jinheung) were evaluated during the 1980 rice growing season. Primary objectives were directed to determine the effects of rates, timing and method of application of the products on the yield of rice. For the Seed Plus test, seed was soaked in the diluted Seed Plus solution(1 : 100) for 24 hours just prior to sowing. The Crop Plus was diluted to 1 : 12 for seedling treatment. Seedling roots were immersed in the diluted solution for 3 hours before transplanting. Crop Plus spray applied at the rates of 450ml/ha or 900ml/ha when rice plants were in the panicle initiation, heading or tillering stage respectively to compare the effects of rates and timing of application. The weather was not favorable for rice growth during the growing season except the tillering stage. The foliar spray at the tillering stage was more effective than the spray at the panicle initiation, and the rates of 900ml/ha showed better results than 450ml/ha. Combination of seed treatment and foliar spray increased grain yield by 16% over untreated control plots.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.2
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• pp.92-97
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• 2001

Soil characteristics and crop productivity was compared between 5 soil physical treatment plots: check, reversion, subsoiling, explosive subsoiling and drainage in salt accumulated Gangseo Fine sandy loam soil from 1999 to 2000. Physical treatments of subsoil improved soil physical properties in the following order, reversion > drainage > explosive subsoiling > subsoiling > check. The effectiveness of physical treatment was sustained to the 2nd year after treatment. Soil moisture content of subsoil was highest in the reversion treatments and decreased in the order of drainage, subsoiling, and check. However there was little difference between treatments. The physical treatments increased fluctuation of soil moisture content. However the crop yield in the physical treatment plots were increased. It was considered that the increase of crop yield was caused by improvement of soil physical properties rather than soil water holding in the soil. An average increase rate of crop yield by physical treatments was 10 to 20 percent.