• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2064-2067
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• 2000

In our country, most region is composed of mountains and people have recently been displeased with the construction of the substations in their vicinity so the substations newly built are mainly constructed with GIS system in the small area that has high soil resistivity near mountain. Therefore, nowadays the design of substation grounding system has been difficult, and the additional considerations are needed. UC substation was also difficult to design the grounding system because of so small substation area and high soil resistivity. This paper shows the examples of reducing the grounding system resistance reasonably by using several ways. Designing the ground grid electrode in the access road, deep electric earth probe, changing the substation soil with the law level resistivity soil. This report deals with the computer simulation of the grounding system resistance about the ways illustrated above.

• Journal of Korean Society of Rural Planning
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• v.21 no.4
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• pp.177-186
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• 2015

The main objective of this study was to assess the applicability of IoT (Internet of Things)-based flood management under climate change by developing intelligent water level monitoring platform based on IoT. In this study, Arduino Uno was selected as the development board, which is an open-source electronic platform. Arduino Uno was designed to connect the ultrasonic sensor, temperature sensor, and data logger shield for implementing IoT. Arduino IDE (Integrated Development Environment) was selected as the Arduino software and used to develop the intelligent algorithm to measure and calibrate the real-time water level automatically. The intelligent water level monitoring platform consists of water level measurement, temperature calibration, data calibration, stage-discharge relationship, and data logger algorithms. Water level measurement and temperature calibration algorithm corrected the bias inherent in the ultrasonic sensor. Data calibration algorithm analyzed and corrected the outliers during the measurement process. The verification of the intelligent water level measurement algorithm was performed by comparing water levels using the tape and ultrasonic sensor, which was generated by measuring water levels at regular intervals up to the maximum level. The statistics of the slope of the regression line and $R^2$ were 1.00 and 0.99, respectively which were considered acceptable. The error was 0.0575 cm. The verification of data calibration algorithm was performed by analyzing water levels containing all error codes in a time series graph. The intelligent platform developed in this study may contribute to the public IoT service, which is applicable to intelligent flood management under climate change.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.10
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• pp.533-543
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• 2003

With the increase of interests in cluster, there have been a number of research efforts to address the high availability issues on cluster. However, there are no kernel-level group communication systems to support the development of kernel-level application programs and it is not easy to use traditional user-level group communication systems for the kernel-level applications. This paper presents the design and implementation issues of KCGCS(Kernel-level Cluster Group Communication System), which is a kernel-level group communication module for linux cluster. Unlike traditional user-level group communication systems, the KCGCS uses light-weight heartbeat messages and a ring-based heartbeat mechanism, which allows users to implement scalable failure detection mechanisms. Moreover, the KCGCS improves the reliability by using distributed coordinators to maintain membership information.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.9
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• pp.952-960
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• 2008

Fan noise prediction method is presented for air conditioning, automobile and electronic cooling system applications where fan acts as an internal equipment having very complicated flow interaction with other various system components. The internal flow paths and distribution in the fan-applied systems such as computer or air conditioner are analyzed by using the FNM(flow network modeling). Fan noise prediction method comprises two models for the discrete frequency noise due to rotating steady aerodynamic lift and blade interaction and for the broadband noise due to turbulent boundary layer and wake vortex shedding. Based on the fan operation point predicted from the FNM analysis results and fan design parameters, the present far noise model predicts overall sound pressure level and spectrum. The predictions for the flow distribution, the fan operation and the noise level in air cooling system by the present method are well agreed with 3-D CFD and actual noise test results.

• Journal of Advanced Navigation Technology
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• v.15 no.5
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• pp.857-864
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• 2011

Today's education make an effort to be done on self-directed learning away from teaching students through a passive learning. In this paper, we implemented leveled incorrect analysis system based on SCORM which targets elementary students in mathematics. This system can analyze learner's weak points of problem scope and problem ability. Also, This led to higher academic achievement in the low level group by compensatory learning of incorrect analysis system according to individual level.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.04a
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• pp.236-239
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• 2009

Since 1990s, we have achieved a certain level of success in standardization of design, construction, and material on housing and public buildings with the national-level promotion. A practical connecting device that can synthesize all the serial processes is required to maximize the effect of construction material standardization. However, desired outcome of the standardization is not achieved yet because these serial standards and notification practices are decided by each part of the process and some are congested. In this study, we aim to improve a general organizational system of Korean Industrial Standard (KS) which is the most fundamental tool for the standardization of construction materials moving from a conventional idea that the standard is only for the material and components producers to a concept that can also be shared by the designers and construction workers. To achieve this, we propose an improvement plan for the Korean Industrial Standard in the perspective of three-tier classification system.

• Journal of the Korean housing association
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• v.20 no.3
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• pp.59-67
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• 2009

Since 1990s, we have achieved a certain level of success in standardization of design, construction, and material on housing and public buildings with the national-level promotion. A practical connecting device that can synthesize all the serial processes is required to maximize the effect of construction material standardization. However, desired outcome of the standardization is not achieved yet because these serial standards and notification practices are decided by each part of the process and some are congested. In this study, we aim to improve a general organizational system of Korean Industrial Standard (KS) which is the most fundamental tool for the standardization of construction materials moving from a conventional idea that the standard is only for the material and components producers to a concept that can also be shared by the designers and construction workers. To achieve this, we propose an improvement plan for the Korean Industrial Standard in the perspective of three-tier classification system.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.5
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• pp.8-14
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• 2015

Heat treatment for car body molds is mainly a manual process performed by a worker. The performance of this process is affected by workers' skill level, and has limitation in maintaining uniform product quality. In this study, we developed a diode laser heat treatment robot system that implements an OLP type simulator to overcome the limitation of manual process, and to improve and stabilize the quality level. In addition, we verified the efficiency of the robot system and mechanism stability from the early stage through design verification and simulated analysis in the development stage. In addition, we carried out a field test to study the way to establish optimized D/B for diode laser heat treatment criteria for car body molds, such as heat treatment speed, interval, etc. via site experiment.

• Journal of Industrial Technology
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• v.15
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• pp.113-122
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• 1995

By integrating WDM to OPS unit which plays an important role for the reliability of CPN, we made it possible to provide CATV, VOD, and high-speed data services simultaneously and to meet the requirements for new services in the future. For the design of optimal system, the link analysis of power budget has been performed. Also, the prototyped system has been tested with STM-1 level signals to confirm functions such as transmission, distribution, and protection. The results proved that when occurred out-of-order or recovery of ONU, the system did the pertinent switching with minimum loss for high-speed data services. Also for video distribution services, the system has distributed STM-1 level signals successfully.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.5
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• pp.550-556
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• 2014

In this study, for the control of a single water tank system, a fuzzy-PID controller design technique based on a fuzzy model is investigated. For this purpose, a water tank system is linearized as a number of submodels depending on the operating point, and a fuzzy model is obtained by fuzzy combining. Each submodel is approximated as a first order time delay model, and a PID controller is designed using several existing tuning techniques. Then, through the fuzzy combination of this controller using the same method as that of the fuzzy model, a fuzzy-PID controller is designed. For the proposed technique, a simulation is performed using the fuzzy model of a water tank system, and the validity is examined by comparing its performance with that of a PID controller.