• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1001-1006
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• 2004

Railroad disasters are frequently occurred by man-made causes or natural causes. In general, man-made causes are illegal construction practices, deterioration with the lapse of time and railroad crossing accidents, and natural causes are rainfall. snow, wind, earthquake, etc. Of cause, railroad disasters by man-made causes are prevented from keeping the safety principle, constructing multi-level crossing, securing enough men of ability and financial resources and making a thorough check using equipments with high capacity. And railroad disasters by natural causes are also minimized by construction of disaster prevention facilities, introduction and operation of general disaster prevention system and reasonable train passage control. Therefore, to setup the criterion of train passage control for train safety at railroad bridge under heavy rainfall, risky factors, national and oversea criteria under such circumstances are reviewed and a scheme to setup the criterion is suggested.

• Journal of the Korean Solar Energy Society
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• v.38 no.4
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• pp.67-76
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• 2018

Cooling the building by natural ventilation is one of the passive methods widely used from ancient times. It can be effectively applied especially in case of cooling load during the intermediate season of the year. In this study, the effect of 4 cases of window ventilation control mode which are 'Always Close', 'Temperature', 'Enthalpy' and 'Always Open' is simulated by Energyplus program and analyzed to improve the comfort of occupants and reduce energy consumption of the school classroom.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1999.11a
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• pp.126-129
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• 1999

Natural ventilation is achieved by air exchanges through multiple openings due to natural pressure variations inside and outside the greenhouse. Wind is the primary driving force making natural ventilation systems very difficult to design properly because of variations in wind velocity and direction. The optimization of these systems for acceptable climate control requires a thorough knowledge of the airflow rates and patterns as related to weather conditions and greenhouse structural details. (omitted)

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.39 no.6
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• pp.9-19
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• 2002

An NAC(Natural Admittance Control) system design is presented for interaction controller that achieves high-performance and guarantees stability. The NAC can be classified as a particular flavor of impedance control similar to control schemes that have velocity compensator and force compensator. The NAC significantly improves the response characteristics when Coulomb friction is presented in One-link Robot System and guarantees stability when robot contacts with environment. Pragmatic rules for NAC synthesis are derived. It shows method to choose a target impedance for realizable force compensator. Important parameters are found experimentally. It is demonstrated, by the experimental result, that NAC algorithm is successful in rejecting Coulomb friction through velocity compensator and guarantees stability through force compensator. We implement an experimental set-up consisting of environment-generated one-link robot system and DSP system for controller development. We apply the natural admittance controller to the One-link robot system, and show the good performance on desired force control in case of contacting with arbitrary environment.

• Women's Health Nursing
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• v.9 no.3
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• pp.299-308
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• 2003

Purpose: This study was designed to identify nurses' perceptions and educational intentions regarding natural childbirth control (NCC) methods. Method: The participants were 313 nurses working at three general hospitals in Seoul. They were asked to complete a questionnaire composed of scales measuring knowledge and perceptions childbirth control methods, awareness of bodily changes in ovulation phase, perceptions of fetal life, which were developed by the author. Also, Chang's (2002) Sexual Autonomy Inventory was utilized. The data were analyzed by the SAS program. Results : Methods of condom and rhythm were considered to be more useful for childbirth control than other methods. Only 34-54% of them knew exactly about the NCC methods using menstrual cycle, body temperature, and mucus. The mean scores of sexual autonomy and awareness of bodily changes in ovulation phase were 3.8 and 3.4 out of 5, in respect. Educational intention was different statistically by the age, marital status, future intention to use NCC methods, and perception of educational need for NCC methods. Conclusion : Nurses' perceptions and educational intentions regarding NCC were low, especially in nurses who were married. It is recommended to encourage nurses to learn NCC methods for clients education.

• Journal of the Korean Institute of Landscape Architecture
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• v.17 no.1
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• pp.1-16
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• 1989

^x As mentioned above, I consider the change of role that is related with Japanese thought of Natural Environmental Conservation, and I divide each part of periods into forest, farmland, open space, urban planning, environmental conservation etc. To summary the content of each period of Natural Environmental Conservation thought is as follows. 1) Previous period before formation(before 1919) In the previous period of Meiji, it could be said that the consciousness of the Natural Environmental Conservation was coming to existence. In this, so called, Natural Environmental Conservation, the thought of Forest Preservation was the main current and it was the thought of territorial integrity for the security of resource, the forestry conservancy and flood control in the forestry farmland. Since the age of Meiji, the theory of Natural Conservation appears from the theory of Japanese landscaping and systematic management about public parks was enforced, but the regular theory of Natural Environmental Conservation did not attain full growth. 2) The period of formation(1919~ 1954) In the period of formation, the base of Natural Environmental Conservation had been established. Parks and Open spaces were admitted as a public facilities in each city, and legislations which supported it had been continuously enacted and so on. In this period, the afforestation counter plan was emphasized on the side of territorial integrity. In the mountainous district. tree planting was emphasized to recover the forest which had been destroied by war. 3) The period of development(1955~ 1974) In the period of development, varied policies was institutionalized for the Natural Environmental Conservation. However, all sorts of development policy had performed simultaneously, thus development had complicated relation with preservation. But after 1970's the framework of system of Natural Environmental Conservation improvement was constituted to control the many kinds of development, and the spontaneous campaign of nature preservation by private lead was being taken root. This is the more progressive period. 4) The pried of root(after 1975) After the latter of 1970's, the role of Natural Environmental Conservation began to take root not in the direction of control but inducement, and, getting out of development - oriented policy, aimed at relation between human being and natural environment and the side of amenity of human environment. Besides, the current of Natural Environmental Conservation had been seperately progressed in the cities and forests. Since this period, it was the character that cities and forests began to be unified as 'amenity'space of man.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.111.4-111
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• 2001

In this paper, an adaptively tuned dynamic absorber is proposed. The adaptively tuned dynamic absorber is a dynamic absorber whose stiffness is tuned so that the natural frequency of the absorber coincides with the operating or natural frequency estimated by an adaptive algorithm. The feature of this absorber is as follows. It has an electrodynamic device for the stiffness control. Using Lorenz´s force, it changes the stiffness by changing the applied current. The change of stiffness results in the natural frequency shift, because its mass and damping coefficient are fixed. We may reduce the vibration of the overall system by tuning the natural frequency of the dynamic absorber to the resonant frequency of the structure, when the dominant single tone oscilation occurs in the system ...

• Journal of Korean Society for Quality Management
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• v.34 no.1
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• pp.73-77
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• 2006

In this paper, the Bayesian procedure for the multiple test of fraction nonconforming, p, is proposed. It is the procedure for checking whether the process is out of control, in control, or under the permissible level for p. The procedure is as follows: first, setting up three types of models, $M_1:p=p_0,\;M_2:pp_0$, second, computing the posterior probability of each model. and then choosing the model with the largest posterior probability as a model most fitted for the observed sample among three competitive models. Finally, the simulation study is performed to examine the proposed method.

• Proceedings of the Korean Society for Quality Management Conference
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• 2006.04a
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• pp.325-329
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• 2006

In this paper, the Bayesian procedure for the multiple test of fraction nonconforming, p, is proposed. It is the procedure for checking whether the process is out of control, in control, or under the permissible level for p. The procedure is as follows: first, setting up three types of models, $M_1:p=p_0,\;M_2:pp_0$, second, computing the posterior probability of each model. and then choosing the model with the largest posterior probability as a model most fitted for the observed sample among three competitive models. Finally, the simulation study is performed to examine the proposed method.

• Journal of Wind Energy
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• v.4 no.2
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• pp.17-24
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• 2013

Idealized PID-controlled rotor-speed error for blade pitch control of wind turbines responds as a second-order system with natural frequency and damping ratio for closed-loop system. RISO National Laboratory has recommended specific natural frequency(=0.6 rad/s) and damping ratio(=0.7) for 2 MW wind turbine. The baseline controller for 5 MW wind turbine of NREL(National Renewable Energy Laboratory) is designed based on the same values of RISO recommendation. This study investigates the effect of the natural frequency and damping ratio of the controller for NREL 5 MW wind turbine. It is confirmed that RISO recommendation shall be tuned for each wind turbine.