• The Korean Journal of Air & Space Law and Policy
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• v.9
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• pp.183-197
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• 1997

• Nuclear Engineering and Technology
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• v.11 no.3
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• pp.219-229
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• 1979

The current status of the computational methods and computer codes for the analysis of reactor kinetics is reviewed. Computational methods which have been developed for space-dependent transient analyses are presented and recent progress in the development of methods is discussed.

• KIEAE Journal
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• v.5 no.2
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• pp.43-49
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• 2005

The purpose of this study is to analyze the form and space of superstructure and to present the characteristics of design innovation and space planning in cruise ships. The exterior design styling and interior space design are induced on the important design concept in cruise ships. The scale and structural daring of the past mega ship and next generation concept is being injected into the current cruise ship design.

• Publications of The Korean Astronomical Society
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• v.15 no.spc2
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• pp.1-13
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• 2000

Through the coupling between the near-earth space environment and the polar ionosphere via geomagnetic field lines, the variations occurred in the magnetosphere are transferred to the polar region. According to recent studies, however, the polar ionosphere reacts not only passively to such variations, but also plays active roles in modifying the near-earth space environment. So the study of the polar ionosphere in terms of geomagnetic disturbance becomes one of the major elements in space weather research. Although it is an indirect method, ground magnetic disturbance data can be used in estimating the ionospheric current distribution. By employing a realistic ionospheric conductivity model, it is further possible to obtain the distributions of electric potential, field-aligned current, Joule heating rate and energy injection rate associated with precipitating auroral particles and their energy spectra in a global scale with a high time resolution. Considering that the ground magnetic disturbances are recorded simultaneously over the entire polar region wherever magnetic station is located, we are able to separate temporal disturbances from spatial ones. On the other hand, satellite measurements are indispensible in the space weather research, since they provide us with in situ measurements. Unfortunately it is not easy to separate temporal variations from spatial ones specifically measured by a single satellite. To demonstrate the usefulness of ground magnetic disturbance data in space weather research, various ionospheric quantities are calculated through the KRM method, one of the magneto gram inversion methods. In particular, we attempt to show how these quantities depend on the ionospheric conductivity model employed.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.11a
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• pp.235-239
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• 2009

The purpose of this study is to apply the basic data of the color plan to satisfy the internal desire of residents by considering residents's special in housing space. So we analyzed and surveyed the current condition of color plan in housing space where age units of 30~40 are living. The results of this study are as followed. when the current place of color distribution was observed, ceiling and general wall showed that N(white) systems and YR of bright tone was mostly distributed. On other hand the bottom showed that the calm tone YR was mostly distributed. we could know that residents wanted to show the special of rooms by using point wall. This tendency more presented in privacy room than public room. Through this study, we could evaluate that the special of residents is not presented in color plan of the housing space where age units of 30~40 are living. So we could think that it is needed methods of color plan considered the special of residents for discriminative characteristic of the design in housing space.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1438-1440
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• 1998

In this work, simultaneous measur of space charge and conduction current was c out in LDPE with air gap by Pulsed-Electro-Aco Method. Also, effect of long time charging at con electric field on the formation of space charge conduction was investigated. From the experim results. we knew that the homo space charge formed near the dielectric surfaces and moving the bulk of dielectric as the electric field elevated. This was related with the deep traps b carriers and de trapping by Poole-field lowering conduction current was coincident with the Pool emission. From the long time charging experimen obtained the results that the negative space was moving into the dielectric bulk as the cha continued and the positive space charge accumulated at upper surface of LDPE.

• Korean Institute of Interior Design Journal
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• v.17 no.4
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• pp.42-49
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• 2008

Design concepts of light can be divided into two respects, visual plastic and metaphysical meaning. The current research focuses on the second respect. The meaning of light is abstract characteristics(for example, divinity, spirituality, or image) ultimately expressed by visual plastic. Because it makes architectural space abundant, it have been expressed frequently in architectural space until now. The purpose of this paper is to conceptualize and explain and arrange the meanings of light in the category that have been expressed in architectural space from ancient to current. The method of this study is content analysis and case study, and this is supplement by theoretical consideration on the meaning of light(relationship between perception and meaning, elements to form meaning etc.). This study consists of three steps. Firstly, through the content analysis of existing literature and documents, 17 meanings of light are confirmed. Secondly, these 17 meanings are defined and explained in 3 categories(symbolic, esthetic, and experiential character). Thirdly, they are additionally explained and articulated by case study. In the result, various meanings of light that have been fragmentarily expressed in architectural space until now is clearly arranged at a glance. Those suggested design concepts will be basic conferential material, available to the interior designers and students who want to utilize the organised study concepts.

• Journal of Power Electronics
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• v.10 no.3
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• pp.285-292
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• 2010

This paper presents a current mode integrated control technique (CM-ICT) using a modified voltage space vector modulation (MSVM) for Z-source inverter (ZSI) fed induction motor drives. MSVM provides a better DC voltage boost in the dc-link, a wide range of AC output voltage controllability and a better line harmonic profile. In a voltage mode ICT (VM-ICT), the outer voltage feedback loop alone is designed and it enforces the desired line voltage to the motor drive. An integrated control technique (ICT), with an inner current feedback loop is proposed in this paper for the purpose of line current limiting and soft operation of the drive. The current command generated by the PI controller and limiter in the outer voltage feedback loop, is compared with the actual line current, and the error is processed through the PI controller and a limiter. This limiter ensures that, the voltage control signal to the Z-source inverter is constrained to a safe level. The rise and fall of the control signal voltage are made to be gradual, so as to protect the induction motor drive and the Z-source inverter from transients. The single stage controller arrangement of the proposed CM-ICT offers easier compensation. Analysis, Matlab/Simulink simulations, and experimental results have been presented to validate the proposed technique.

• Journal of Power Electronics
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• v.17 no.6
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• pp.1563-1576
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• 2017

This paper presents a novel switching pattern current control (SP-CC) scheme, which is applied in three-phase voltage-source converters (VSCs). This scheme can select the optimal output switching pattern (SP) by referring the basic principle of space vector modulation (SVM). Moreover, SP-CC is a method without a carrier wave. Thus, the implementation process is concise and easy. When compared with the conventional hysteresis current control (C-HCC) and the space vector-based hysteresis current control (SV-HCC), the SP-CC has the performances of faster dynamic response of C-HCC and less switching number (SN) of SV-HCC. In addition, it has less harmonic contents in the three-phase current, along with a lower switching loss and a higher efficiency. Moreover, the hysteresis bandwidth and Clarke conversion are not required in the SP-CC. The effectiveness of the presented SP-CC is verified by simulation and experimental test results. In addition, the advantages of the SP-CC, when compared with the C-HCC and SV-HCC, are verified as well.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.7
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• pp.127-133
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• 2001

The effects of triangular and rectangular discharge current waveforms on anode erosion in wire electric discharge machining is investigated based on heat transfer analysis of half-space subject to time and space-dependent heat flux. The thermal load on the anode is simulated by a hear flux that is calculated from time-dependent discharge channel radius and energy. Evolution of the melting front during discharge, the molten volume at the experimental result for qualitative verification of the analysis. It is demonstrated that the triangular current waveform is more efficient in eroding the anode than the rectangular one.