• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.04a
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• pp.35-36
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• 1999

• Journal of the Korea Computer Industry Society
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• v.2 no.2
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• pp.141-150
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• 2001

Within a context of rapid technological change and shifting market conditions, the education environment requires new paradigm of education delivery. In accordance of such a technological progress, distance education system, which makes the learning take place at anytime anywhere, overcoming barriers of time, or distance, is emerging as a mainstream of education delivery replacing the convectional one way delivery system from instructor to learners. This paper aims to introduce the development principle and algorithm about Instructional System Desgin(ISD) module, a part of a total solution for distance education services. It was developed on Linux, a free Unix-type operating system. Linux supports so various network protocols, sharing the network resources in a smooth way, that it is able to integrate with other operating system very easily, especially with Windows NT or Windows 2000 servers. In terms of quality, it never falls behind the windows products which are commercially available only. It is a right operating system for the such a school environment that is usually limited in budgets. The development environment of the distance education solution to which ISD module belongs is composing of Apache server for web server, lava bean based on components for ISD module, PHP, server-side scripting language, for HTML documents and MySQL for DBMS.

• The KIPS Transactions:PartC
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• v.12C no.7 s.103
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• pp.999-1006
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• 2005

The Secure OS is an operating system which adds security functions to the existing operating system, in order to secure a system from sorority problems originated from inherent frailty of applications or operating systems. With the existing Secure Oses for it is difficult to set an effective security policy securing personal resources in a multi-user environment system. To solve this problem in this paper we present two Techniques to secure user data efficiently in the RBAC-based Secure OS for a multi-user environment. Firstly we utilizes object's owner information in addition to object's filename. Secondly we make use of meta symbol('$\ast$'), which is able to describe multiple access targets. In addition this paper gives some examples to show advantages from these techniques. And these features are implemented in an solaris-based Secure OS called Secusys.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.5
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• pp.477-486
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• 2005

In this study, indoor thermal environment, resident behavior of operating cooling device, and thermal comfort vote are investigated at the living room of apartment during summertime in Seoul. Based on the results of the investigation, indoor air temperatures that residents turn air conditioners (especially for cooling load in this research) on and off were found out. The relationships between outdoor weather condition and the number of days using air conditioner, and whether operating patterns of the devices were also found out. The acceptable thermal comfort zone is figured out from these results, and this research is expected to contribute to the development of household air conditioner. The results can be summarized as the followings; Residents turned the air conditioner on at $29.76^{\circ}C$ of indoor air temperature, and $28.89^{\circ}C$ of $SET^\ast$. And turned the air conditioner off at $27.31^{\circ}C$ of indoor air temperature, and $23.70^{\circ}C$ $SET^\ast$. Therefore, acceptable thermal comfort zone could be lied between these temperatures. If comfortable indoor thermal environment can be obtained with various architectural passive cooling techniques based on the results, energy consumption of cooling devices will be reduced.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2000.11a
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• pp.635-645
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• 2000

Within a context of rapid technological change and shifting market conditions, the education environment requires new paradigm of education delivery In accordance of such a technological progress, distance education system, which makes the loaming take place at anytime anywhere, overcoming barriers of time, or distance, is emerging as a mainstream of education delivery replacing the convectional one way delivery system from instructor to learners. This Paper aims to introduce the development principle and algorithm about Instructional System Design(ISD) module, a part of a total solution for distance education services. It was developed on Linux, a free Unix-type operating system. Linux supports so various network protocols, sharing the network resources in a smooth way, that it is able to integrate with other operating system very easily, especially with Windows NT or Windows 2000 servers. In terms of quality, it never falls behind the windows products which are commercially available only, It is a right operating system for the such a school environment that is usually limited in budgets. The development environment of the distance education solution to which ISD module belongs is composing of Apache server for web server, Java bean based on components for ISD module, PHP, server-side scripting language, for HTML documents and MySQL for DBMS.

• Journal of Korean Society on Water Environment
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• v.40 no.2
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• pp.89-100
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• 2024

Climate change has a broad impact on the entire water environment, and this impact is growing. Climate adaptation in water supply systems often involves quantity and quality control, but there has been a lack of research examining the impacts of climatic factors on water supply productivity and operation conditions. Therefore, the present study focused on, first, building a database of climatic factors and water purification operating conditions, and then identifying the correlations between factors to reveal their impacts. News big data was analyzed with keywords of climatic factors and water supply systems in either nationwide or region-wide analyses. Metropolitan area exhibited more issues with cold waves whereas there were more issues with drought in the Southern Chungcheong area. A survey was conducted to seek experts' opinions on the climatic impacts leading to these effects. Pre-chlorination due to drought, high-turbidity of intake water due to rainfall, an increase of toxins in intake water due to heat waves, and low water temperature due to cold waves were expected. Pearson correlation analysis was conducted based on meteorological data and the operating data of a water purification plant. Heavy rain resulted in 13 days of high turbidity, and the subsequent low turbidity conditions required 3 days of high coagulant dosage. This insight is expected to help inform the design of operation manuals for waterworks in response to climate change.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.213-218
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• 2001

VR (Virtual reality) technologies have given engineers the ability to design, test, and evaluate engineering systems in a virtual environment. The virtual plant is the highlight of the application of the VR technology to plant engineering. Plant design, maintenance, control, management, operation are integrated in the virtual plant. The VR monitoring system including the concept of the virtual plant is developed to replace a current control room that has number of gages and warning lamps in two-dimensional panels which shows the operating status of a plant. The operating status of the plant is displayed in the VR monitoring system through the realistic computer graphics. Sophisticated, realistic and prompt control becomes possible. The VR monitoring system consists of advanced visualization, walk-through simulation and navigation. In the virtual environment, a user can navigate and interact with each component of a plant. In addition, the user can access the information by just clicking interesting component. The VR monitoring system is operated with various modules, such as (1) virtual plant constructed with Graphic Management System (GMS), (2) Touch & Tell System, and (3) Equipment DB System of Part. In order to confirm the usefulness of the VR monitoring system, a pilot gas plant which is currently being used for plant operator training is taken as application. The end of the paper gives an outlook on the future work and a brief conclusion.

• Korean Journal of Organic Agriculture
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• v.18 no.3
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• pp.331-345
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• 2010

The objective of this paper is to analyze management performance of organic farming management organizations in the large-scale environment-friendly agricultural districts, focusing on cases of organic farming organizations in Chungnam Asan city and Gyeongnam Sancheong-gun which are leading regions in Korean organic agriculture. The management performance in Asan Organic Farming Organization showed that ratio of operating gain to revenue in 2008~2009 increased by 1.2% point compared to in 2006~2007. The management performance in Sancheong Organic Farming Organization showed revenue gain by KRW 2 million in 2009 whereas it suffered a loss by KRW 24 million in 2008. The management performances implied that the amount of financial performance was not yet large and would be a symbol for soundly developing organic farming organization. This paper suggested that network system, recycling agriculture, and the enlargement of processing industry would be very useful to maximize synergy effect in organic farming organizations in a large-scale environment-friendly agricultural districts.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.2
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• pp.679-687
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• 2019

This paper presents the autonomous swimming technology developed for an Autonomous Underwater Vehicle (AUV) operating in the underwater jacket structure environment. To prevent the position divergence of the inertial navigation system constructed for the primary navigation solution for the vehicle, we've developed kinds of marker-recognition based underwater localization methods using both of optical and acoustic cameras. However, these two methods all require the artificial markers to be located near to the cameras mounted on the vehicle. Therefore, in the case of the vehicle far away from the structure where the markers are usually mounted on, we may need alternative position-aiding solution to guarantee the navigation accuracy. For this purpose, we develop a sonar image processing based underwater localization method using a Forward Looking Sonar (FLS) mounted in front of the vehicle. The primary purpose of this FLS is to detect the obstacles in front of the vehicle. According to the detected obstacle(s), we apply an Occupancy Grid Map (OGM) based path planning algorithm to derive an obstacle collision-free reference path. Experimental studies are carried out in the water tank and also in the Pohang Yeongilman port sea environment to demonstrate the effectiveness of the proposed autonomous swimming technology.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.149-150
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• 2006

In this paper, design, simulation, fabrication method, and measured results of a digital frequency discriminator(DFD) operating in E, F, and G band are introduced. We describe the direct conversion scheme(DCS) with microwave integrated-circuit(MIC) developed for the small-area and high-speed system. When the input signal is the pulse with a pulse width of 100 ns, accuracy of frequencies measured by the DFD has 1.335 MHz RMS at no noise and 2.64 MHz RMS at signal-to-noise(S/N) ratio within 3 dB in E, F, and G band, which nearly satisfy the specification of 2.5 MHz RMS.