• Journal of Power Electronics
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• v.13 no.3
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• pp.390-399
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• 2013

As a result of the depletion of fossil fuels and environmental contamination, it has become important to use renewable energy. For the stable utilization of renewable energy sources, energy storage devices must be used. In addition, renewable and distributed power sources with energy storage devices must operate stably under grid-connected mode. This paper proposed dynamic response modeling for renewable power generation systems including a charger/discharger with an energy storage device in order to derive a method to guarantee stable operation while fully utilizing the energy from the energy storage device. In this paper, the principle operation and design guidelines of the proposed scheme are presented, along with a performance analysis and simulation results using MATLAB and PSIM. Finally, a hardware prototype of a 1kW power conditioning system with an energy storage device has been implemented for experimental verification of the proposed converter system.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.559-563
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• 2015

Identification of energy use patterns in buildings has a great opportunity for energy saving. To find what energy use patterns exist, clustering analysis has been commonly used such as K-means and hierarchical clustering method. In case of high dimensional data such as energy use time-series, data reduction should be considered to avoid the curse of dimensionality. Principle Component Analysis, Autocorrelation Function, Discrete Fourier Transform and Discrete Wavelet Transform have been widely used to map the original data into the lower dimensional spaces. However, there still remains an ongoing issue since the performance of clustering analysis is dependent on data type, purpose and application. Therefore, we need to understand which data reduction techniques are suitable for energy use management. This research aims find the best clustering method using energy use data obtained from Seoul National University campus. The results of this research show that most experiments with data reduction techniques have a better performance. Also, the results obtained helps facility managers optimally control energy systems such as HVAC to reduce energy use in buildings.

• Journal of the Korean Solar Energy Society
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• v.30 no.4
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• pp.1-8
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• 2010

The mechanical parts of small windp ower generator less than 10kW are manufactured in the form of removing most of the accelerators. The braking system to protect blade from damages caused by high wind speed is manufactured in a manner having apparatus system(furling), manual brake or no brake. This study is on braking system in small size wind power generator, and carried out survey as following steps by applying electric braking system which uses armature reaction. We explained the principle of electric braking system and the principle of existing braking system. Also, this paper interpreted short circuit current through open circuit and short circuit, as well as checking brake system's action using armature reaction with real construction of control device.

• The Journal of Internal Korean Medicine
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• v.19 no.1
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• pp.73-81
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• 1998

This study was performed on the basis of clinical consideration about patient who has hepatoma, cholangiocarcinoma and pancreatic cancer. Cancer has gradually increased morbidity and mortality all over the world including Korea. Western medicine has treated with surgical therapy, chemotherapy, radiotherapy and immunotherapy, but has not obtained outstanding results and has a difficulty due to side effects by those therapies. In this study, we recognized that symptom including pain by cancer are rapidly decreased with oriental medicine treatment. Oriental medicine treatment is applied throughly on the basis of the oriental medicine principle and the prescrptions were used Bulwhankumjunggisan(不換金正氣散), Sojukbaekchulsan(消積白朮散) Banhabackchulchunmatang(半夏白朮天麻湯). The communitial effect of those prescriptions are invigorating the spreen and benefiting vital energy(健脾益氣), supporting healthy energy to eliminate evils(扶正祛邪) and those treatments are corresponed with traditional oriental treatment principle. Also we can know this patient has a little improvement in the general test including biochemistry, blood test, urine analysis and etc. in spite of outstanding improvement of patient's symptom on administration of oriental medicine. According to the above results, though we has not got satisfaction in getting rid of cancer completely on administration of oriental medicine, it is helpful in decreasing symptoms including pain by cancer and in improving quality of life of patient and in improving quality of patient life.

• Korean Journal of Child Studies
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• v.35 no.5
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• pp.63-82
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• 2014

The purpose of this study is to elucidate how two young children understand force in rough-and-tumble play. For this purpose, a form of microanalysis(Forman, 2006) was used. They regarded black as the strongest color due to their daily experiences. They assumed that a structure made of black Lego-color-bricks would be strongest and made an experiment of beating it against blocks of other colors. Such repetitive behavior ultimately led them to realize that color had no correlation with strength. They also understood mechanical energy by which a boy's pushing power moves against an object. They tried to strike a bigger or protruding structure and understood that parts might be broken more easily by striking. This experience enabled the boys to realize the principle of resistance. That is to say, in the process of rough-and-tumble play, their misconceptions were gradually removed and they obtained scientific knowledge, including understanding of mechanical energy and the principle of resistance. This study found that two young children constructed knowledge together through the process of tool making and in contending for victory in rough-and-tumble play.

• Journal of the Daesoon Academy of Sciences
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• v.26
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• pp.77-110
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• 2016

The purpose of this article is to study on the Correlative linkage between the cosmic principle of birth-growth and contraction-recess and the Non action Tao. The split time between birth-growth and contraction-recess is the conflict between the Prior Time and Posterior Time as the Great Renewal. The cycle of this Chaotic Renewals is the cycle of a cosmic circulation as 129,600 years. In relation to the correlative linkage of function, Jeong-san Sangje governs all the beings of the universe by means of the cosmic principle birth-growth and contraction-recess. Also Jeong-san Sangje, using the Non action Tao governing all the beings of the universe and let them exist as the original selves. Thus, the two necessities are mutual interdependent and mutual complementary. In relation to the correlative linkage of substance, Jeong-san Sangje is included in the cosmic life which forms of all the existences. That is personal God of Jeong-san Sangje that is a part of the cosmic life. So that Jeong-san Sangje is included in the cosmic life, the basis of all the cosmic affairs. He is also subordinate to the cosmic principle but he simultaneously governs it. Jeong-san Sangje is trans-versal mediator between the cosmic principle and the cosmic life of Non action Tao, since it is the origin of his mind. To understand the nature of Jeong-san Sangje who becomes one with the cosmic life, the old causal way of thinking which inquires the timely order and seeks for causes and effects should be abandoned. The new way of thinking is thus different from the old one. The core of cosmic life is abstracted as the essence-energy and god-blood. This structure is similar to the cosmic principle of birth-growth and contraction-recess. The death is a kind of event caused by the depletion of the essence, and all beings could altered into the god. It also would be returned to the natural birth place of the cosmos, as it were, that can be called the 'Return to the Origin'. As the cosmos goes to the new epoch, humans have been living together with the cosmic principle. Now we can expect the Posterior Time to open to humans as cosmic life of Non action Tao.

• Journal of the Korean Institute of Gas
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• v.10 no.4 s.33
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• pp.17-22
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• 2006

Both of district heating(DH) system and natural gas(NG) supply system have benefits in clean energy supply and having energy efficiency and savings. The issue of duplicate investment and supply requirement of only for cook occur several conflicts such as destruction of the Beneficiary Pays Principle and Cross Subsidization, etc. Under the circumstance, the purposes of this research are to consider several issues of cross subsidization in NG and DH industries and to present the following alternatives for resolving related problems. First of all, a charging mechanism in the energy cost must be improved so as to maintain the positive relation between cost and benefit. That is, the beneficiary-pay principle must be strictly applied. Secondly, the extended supply of DH through HOB(Heat Only Boiler) must be strictly limited. Finally, we need to improve efficiency for the benefit of market participants.

• Journal of the Korean Chemical Society
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• v.40 no.7
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• pp.483-491
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• 1996

Dieis-Alder reaction between cyclopentadiene and 5-membered ring compounds which have exo-cyclic double bond has been studied using the PM3 method. Transition states do not show large geometrical change with the variation of dienophiles. Two isomers are possible due to the rotation of the exo-cyclic double bond of a dienophile. The reactivity for the formation of different products are explained using the FMO energy gap. The exo and endo selectivity of the reaction has been also studied from the correlation between the deformation energy and the activation barrier. Minimum energy reaction path is discussed using the Curtin-Hammett principle.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.2
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• pp.14-26
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• 2002

A new model for degenerate semiconductor quantum well devices was developed. In this model, the multi-subband Boltzmann transport equation was formulated by applying the Pauli exclusion principle and coupled to the Schrodinger and Poisson equations. For the solution of the resulted nonlinear system, the finite difference method and the Newton-Raphson method was used and carrier energy distribution function was obtained for each subband. The model was applied to a Si MOSFET inversion layer. The results of the simulation showed the changes of the distribution function from Boltzmann like to Fermi-Dirac like depending on the electron density in the quantum well, which presents the appropriateness of this modeling, the effectiveness of the solution method, and the importance of the Pauli -exclusion principle according to the reduced size of semiconductor devices.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.696-698
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• 2001

This paper considers the research of the hybrid interrupter which adopts both rotating arc and thermal expansion technology. The operating principle of this device depends on rapid arc rotation due to the magnetic field created by the fault current through a coil which is mounted on contacts and also relies on the principle of thermal expansion created by arc energy in extinguishing chamber and finally causes pressure rise in expansion volume. To develope this type of interrupter, we introduced analytical analysis including electromagnetic and arc fluid simulation and experimental analysis including construction of current source generation facility and arc behavior measurements. In this research, the principle of the interrupting techniques are given and analytical and experimental results of hybrid interrupter which is developed by new technology is introduced.