• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.77-80
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• 2003

We design the local oscillator system of the 100 GHz band radio receiving system for a cosmic radio observation. We use the YIG oscillator with digital driver which is the main oscillator. This oscillator has a good frequency and phase stability at some temperature variation, and the easy computer aided control characteristics. This total system designed to two subsystem, first is the oscillator system include YIG oscillator, tripler, harmonic mixer and triplexer etc., second is the PLL system to supply the precise and stable local oscillator frequency to mixer. The proposed local oscillator system in this paper can be use a single or multi pixel receiver because this system can be lock the local oscillator frequency automatically using PC.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.28 no.3
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• pp.58-64
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• 2005

Customer sensibility based recommendation agent system was developed to tailor to the customer the suggestion of goods and the description of store catalog in on-line shopping mall. The recommendation agent system composed of five modules and seven services including specialized algorithm. This study was to investigate the effectiveness of the customer sensibility based recommendation agent system in on-line shopping mall. This study asked 30 male and female students to perform the task in on-line shopping mall and facilitated them questionnaires. The questionnaires were administered to subjects to measure quality precision, ease of use, support of buying, purchasing power, future intention of the system. The study revealed that good part of the subjects positively evaluated the customer sensibility based recommendation system except for ease of use. The study on usability of the recommendation agent system has need to be performed in next. This paper shows that the satisfaction and the buying power of customers may be improved by presenting customer sensibility based recommendation in on-line shopping mall.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.9
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• pp.506-512
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• 2003

In this paper, a communication module between Relay agents in a multi-agent system based power distribution network protection system is realized using DNP3.0(Distributed Network Protocol), which is the standard communication protocol of distribution automation system in KEPCO. The key words for agent communication in the multi-agent based protection system are defined and represented by use of DNP application function code. The communication module developed based on the proposed communication scheme is tested by use of the Communication Test Harness, a test tool for DNP protocol, then used to the multi-agent system based power distribution net work protection system.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.4
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• pp.530-534
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• 1996

A novel phase error predictor is proposed for servo system in home-use VCRs. The multirate system in VCRs is converted into a single period sampling system with faster sampling time by using the proposed novel phase error predictor. And the disturbances can be measured much faster. From the experimental results, we can see that the perfomance of the control system is improved greatly. The phase lock time of the proposed servo system is ten times faster than that of the conventional system.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1556-1558
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• 2005

As a result of the advancement of radio communications technologies, some investigations are in progress to apply this technologies to a train control system. Most of these investigations are focused on the train safety distance control between a preceding train and a succeeding train, an interlocking system uses train circuits to control the railway path. To make the best use of advantages and improve the safety of radio communications based train control systems, the interlocking system must use radio communications technologies. And the safety level of this system must be equal to track circuit based interlocking systems. This paper describes the train location detection method, the system configuration and the system safety of the new system.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.4
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• pp.388-396
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• 2011

Sun tracking system is the most important subsystem in parabolic dish type solar thermal power plant, since it determines the amount of thermal energy to be collected, thus affects the efficiency of solar thermal power plant most significantly. Various types of sun tracking systems are currently used. Among them, use of photo sensors to located the sun(which is called sensor type) and use of astronomical algorithm to compute the sun position(which is called program type) are two of the mostly used methods. Recently some uses CCD sensor, like CCD camera, which is called image processing type sun tracking system. This work is concerned with the analysis of sun tracking performance of various types of sun tracking systems currently used in the parabolic dish type solar thermal power plant. We first developed a sun tracking error measurement system. Then, we evaluate the performance of five different types of sun tracking systems, sensor type, program type, hybrid type(use of sensor and computed sun position simultaneously), tracking error compensated program type and image processing type. Experimentally obtained data shows that the tracking error compensated program type sun tracking system is very effective and could provide a good sun tracking performance. Also the data obtained shows that the performance of sensor type sun tracking system is being affected by the cloud significantly, while the performance of a program type sun tracking system is being affected by the sun tracking system's mechanical and installation errors very much. Finally image processing type sun tracking system can provide accurate sun tracking performance, but costs more and requires more computational time.

• Journal of the Korean Professional Engineers Association
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• v.16 no.1
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• pp.20-34
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• 1983

A phenomenon in the unplanned urban sprawl of Cheong-ju city has to be rest-rained from disposing and to develop, though progress in urbanization inevitably decreases rural area. So, this thesis aims at reviewing, revising and guiding toward the more effective land use planning practice and zoning mechanism and system of Cheong-ju city. I proposed that land use planning should be had several factors and thereupon that Korean zoning mechanism and system including Building Code should be amended because of inducing human activities in buildings and facilities not to demarcate and plan every one of them. First, the factors of urban planning are a rather diversified approach to it than a unified, supplementation of the applicable difference in time between preparing and appling it, a solid controlling system, a micro and macro planning theory and giving serious consideration for the inertia from the existing land use. Second, the applicable amendments for our zoning mechanism including Eluding Code are as follows; a need of reorganization for Zoning Ordinance appricated to different regulation concerning a scale and peculiarity of a oily, a decision of the different earmarked confinement in area to different zone ana from Zoning Ordinance in City Planning Law, a demarcated facilities and the more detailed land use concerning human activies than the exsisting and entrusting decision on the ways and processes of it to every rural city planning committee, a settlement of zone ana area considering for block-unit and Planned Unit Development(P. U. D.), and a need of security jurisprudence in order to solve the zoning regulation rather in City Planning Law than in Building Code that our zoning regulation and controlling system are depended on. According to these applicable amendments to Cheong-ju city, I proposed the conceptions of Cheong-ju city land use planning are as follows; a reinforcement with one cored pattern of urban land use, a selection of gradual urban sprawl by way of city development and renewal, a strengthening accessibility to the core of the city with Plurizing the system of arterial roads, a choice of priority to conservation at the core of tile city and security of open spaces and parking area at the area of the city, a harmonization between development and conservation at the inner ring area that is situated between the core and periphery reserved area in order to develop in the future, a buffered open space situated at the congested area with heterogenous functions, and a completion of urban open space system. The proposal made here so far is for the hope of the better structure of Cheong-ju city that should be granted to the peculiarity developed with educational, cultural, conservative and self-sufficient city functions.

• The Korean Journal of Emergency Medical Services
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• v.11 no.1
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• pp.53-64
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• 2007

Purpose: Ths study aims to examine characteristics of patients using emergency room after execution of five-day workweek system by government and provide basic materials for operation of efficient emergency room. Methods: Data were collected tbrough medical records of patients visiting emergency room from July of 2004 to October of 2006 and they were analyzed with SPSSlPC 10.0. Conclusion : 1. The number of patients visiting emergency room was average 16.7 persons a day in 2004, 17.5 in 2005 and 18.6 in 2006 and it was found that it was increasing every year since the execution of five-day workweek system 2. Gender distribution of subjects using emergency room was higher in male than in female every year. 3. Means of transport to emergency room were mostly private car and others(public transport or on foot), but use of ambulance was increasing. 4. Residential areas of subjects were mostly 'Myeon area' in 2004~2005, but it was changed to residents at 'Eup area' in 2006. 5. Distribution of patients by medical departments was highest in internal medicine and surgery in 2004~2006 and rate of visiting pediatrics was increasing every year. 6. Time to stay at emergency room was most at 'below 30 min'. in 2004~2006, but cases of stay for 'more than 2 hours' were increasing every year. 7. On presence or absence of trauma in patients visiting emergency room, rate of visit to emergency room with 'no trauma' was higher and this result was increasing every year. 8. As a result of classifying severity of patients visiting emergency room, use rate of emergency room by 'non-emergency' patients was over 90% in 2004~2006 and such a phenomenon was deepened in 2006 compared to that in 2004. 9. Measures after emergency care of patients were most in case of 'discharge' in 2004~2006, but cases of admission to hospital after emergency care were increased every year. 10. According to use of emergency room by a day of the week, use on Sunday was most frequent in 2004~2006, but use on Friday the day before holiday was increasing. 11. According to distribution by age, use by those between '40~49' was most in 2004~2005, but use by those 'below 10' was most in 2006. 12. According to time to visit emergency room, using emergency room at "15:31~23:30 was most in 2004~2006, cases of visiting emergency room at day working hour were decreased every year and those at evening and night working hours were increased. Conclusion: In sum, it was found that characteristics of patients visiting emergency room and their actual status were changed after the execution of five-day workweek system and efforts to rearrange emergency medical system are required.

• The Journal of Korean Association of Computer Education
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• v.11 no.1
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• pp.47-55
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• 2008

The purpose of this study is finding factors affecting the teachers' use of Edunet and exploring the developmental direction of Edunet which is a web based comprehensive educational information service system. Based on the technology acceptance model and the results of the previous studies, five external and three internal factors influencing the use of Edunet were extracted. The participants were 100, the group of field-assistants who were expected core users in Edunet, and the response of questionnaire was gathered by online survey system. To analyze the collected data and the hypothesis, multiple regression was employed. The result indicated that "usefulness" and "trust" affected statically to both (a) the use and (b) the future-intention use of Edunet. "Fitness of instruction" and "ease of use" affected to (c) the usefulness of Edunet. (d) The ease of use of Edunet was affected by "self-efficiency", "contents quality" and "the system-performance" of Edunet.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.4
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• pp.803-810
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• 2017

Recently, social security problems have been caused by the development of the software industry, and a variety of automation techniques have been used to verify software stability. In this paper, we propose a method of automatically detecting a use-after-free vulnerability on Windows system calls using dynamic symbolic execution, one of the software testing methods. First, a static analysis based pattern search is performed to select a target point. Based on the detected pattern points, we apply an induced path search technique that blocks branching to areas outside of interest. Through this, we overcome limitations of existing dynamic symbolic performance technology and verify whether vulnerability exists at actual target point. As a result of applying the proposed method to the Windows system call, it is confirmed that the use-after-free vulnerability, which had previously to be manually analyzed, can be detected by the proposed automation technique.