• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1770-1771
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• 2011

In mission planning of UAV applications, especially for the missions requiring height transitions, it is required to generate reference flight trajectories considering the performances of the engine installed in the UAV. Even though the vertical line following guidance based height transition trajectory generation method has been developed to build reference height transition trajectories easily, it is not adequate for considering engine performances effectively since many engine characteristics and performances have conventionally been described in the V-H(speed-height) plane which is not the very space where the UAVs are actually flying. In this paper, we derive the trajectories in V-H plane for the vertical line following flights. And based on the results, a new algorithm to design the reference height transition trajectories for UAV applicaions. Simulation results demonstrate that the proposed algorithm is very effective and easily applicable.

• Proceedings of the KIEE Conference
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• summer
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• pp.342-344
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• 2004

In conventional small signal stability analysis, system is assumed to be invariant and the state space equations are used to calculate the eigenvalues of state matrix. However, when a system contains switching elements such as FACTS devices, it becomes non-continuous system. In this case, a mathematically rigorous approach to system small signal stability analysis is by means of eigenvalue analysis of the system periodic transition matrix based on discrete system analysis method. In this research, RCF(Resistive Companion Form) method is used to analyse small signal stability of a non-continuous system including switching elements'. Applying the RCF method to the differential and integral equations of power system, generator, controllers and FACTS devices including switching elements should be modeled in the form of state transition matrix. From this state transition matrix eigenvalues which are mapped to unit circle can be calculated.

• Korean Institute of Interior Design Journal
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• v.15 no.4 s.57
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• pp.37-45
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• 2006

The purpose of this study is to stand assembly the meaning and function of entry space with analysing their social and cultural characteristic. The entry space is the linkable place between inner space and out space, and that is the transition place to be experienced two opposing characteristic. Till now the entry space has not taken effect as symbol needed to the resident and observer, and that has been a tendency to shrink as the minimal sign of entrance. So thus, it is in need of studying the entry space's specific and characterizing structurally as expanded function. For the purpose, this study define newly the meaning, function and composition of entry space in an apartment building, and try to find how to reinforce a resident identity. This study propose justification that the entry space isn't boxing space minimally but enforcing symbol presented clearness of composition and vital character.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.3
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• pp.210-216
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• 2013

Rotor blades experience mechanical loads caused by the turbulent wind shear and an impulse-like wind due to the tower shadow effect. These mechanical loads shorten the life of wind turbine. As the size of wind turbine gets bigger, a control system design for mitigating mechanical loads becomes more important. In this paper, individual pitch control(IPC) for the mechanical loads reduction of rotor blades in a transition wind speed region is introduced, and simulation results verifying IPC performance are discussed.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.2
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• pp.69-79
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• 1999

This study identifies the features of landscape elements on the fifteen districts with the idea of land use area and visual quantity of pictures by analyzing the air photo. Therefore, the sensibility of observer is comprehended through simulating the landscape evaluation and the landscape preference with using slide film. The study is divided into three periods to understand the transition of rural landscape as the social and cultural environments have been changed. The first period is the New Community Movement which affected the rapid change of social and cultural environments. The second and third periods are the prior and post time at the rearrangement of administration district in the Tae-Jeon Broad City. The result of this study is explained below part; 1. The transition of rural landscape has been occurred as the land use pattern has been altered. The change of pattern has affected an increase of the natural space and the structure change of agricultural productive space. 2. In the regression analysis, the regression model of landscape preference and land use ratio show; Landscape preference = 3.632 - 11.618 (Residential Area) - 4.227 (Equipped Farm). The explanation variables defined as Residential Area and Equipped Farm, and the relationship of those factors shows negative. Therefore, the increase of other building will make the rural landscape lower and worse.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.3
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• pp.347-359
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• 2015

A method of describing the rovibrational energy transitions and coupled chemical reactions in the direct simulation Monte Carlo (DSMC) calculations is constructed for $H(^2S)+H_2(X^1{\Sigma}_g)$ and $He(^1S)+H_2(X^1{\Sigma}_g)$. First, the state-specific total cross sections for each rovibrational states are proposed to describe the state-resolved elastic collisions. The state-resolved method is constructed to describe the rotational-vibrational-translational (RVT) energy transitions and coupled chemical reactions by these state-specific total cross sections and the rovibrational state-to-state transition cross sections of bound-bound and bound-free transitions. The RVT energy transitions and coupled chemical reactions are calculated by the state-resolved method in various heat bath conditions without relying on a macroscopic properties and phenomenological models of the DSMC. In nonequilibrium heat bath calculations, the state-resolved method are validated with those of the master equation calculations and the existing shock-tube experimental data. In bound-free transitions, the parameters of the existing chemical reaction models of the DSMC are proposed through the calibrations in the thermochemical nonequilibrium conditions. When the bound-free transition component of the state-resolved method is replaced by the existing chemical reaction models, the same agreement can be obtained except total collision energy model.

• Korean Institute of Interior Design Journal
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• v.15 no.6 s.59
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• pp.111-119
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• 2006

The spatial property of contemporary library is now rapidly changing through the spatial expansion of knowledge and information, the reduction of information storing facility, the variation of approaching methods by digital shift and the transition of social recognition as a cultural facility. Also the spatial characteristics with referring characters have developed such as, decentralization, de-construction, de-boundary, individual space, erasing of boundary, flow of space which extends infinitely. The main process of library origination, the systematic classification, and the storage system concluding with the demand and value of the information by changing social demands and the role of the widest ranged facility. And 5 themes, such as, hierarchy, center, storage, boundary, and symbol, as a changed spatial concept and analyzed in the case of library plans and libraries which are actually built. The significant purpose of this research is to propose that rhizomatous intellectuality and hypertext could be a theoretical background of the contemporary architecture and could be a viewpoint of the transition of spatial structure in libraries. A future library should have spatial property embracing various social changes and needs and for this respect, it is necessary to approach and analyze through the architectural explication from diverging points of view.

• Journal of the Korean Ceramic Society
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• v.32 no.5
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• pp.582-586
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• 1995

The crystal structures of (Na0.3Sr0.7)(Ti0.7M0.3)O3 (M=Ta, Nb) compounds were determined using the Rietveld method. Due to the tilting of a oxygen octahedron, (Na0.3Sr0.7)(Ti0.7Nb0.3)O3 had a superlattice of doubled a, b and c of simple perovskite. The crystal structure of (Na0.3Sr0.7)(Ti0.7M0.3)O3 was tetragonal with a space group 14/mmm. The crystal structure of (Na0.3Sr0.7)(Ti0.7M0.3)O3 was a cubic with space group Pm3m, in which no tilting of oxygen octahedron was observed. The difference in the oxygen tilting of these two materials was due to the larger covalency of Nb-O bond than that of Ta-O bond, which induced a strong $\pi$Nb0 bonding in (Na0.3Sr0.7)(Ti0.7M0.3)O3. Therefore, the higher transition temperature of (Na0.3Sr0.7)(Ti0.7M0.3)O3 could be related to the larger tilting of oxygen octahedron.

• Journal of the Economic Geographical Society of Korea
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• v.24 no.4
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• pp.386-399
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• 2021

This study targets the rapidly growing electric vehicle industry. Currently, China is the world's largest electric vehicle producer, and several global and local companies are adapting to the transition environment of the electric vehicle industry and carrying out various activities. To analyze the causes and environmental characteristics of this transition, we analyzed the activities of the Chinese government, automobile companies, and companies in forward and backward linked industries, which are major actors in the production network. As a result, with full support from the Chinese government, functional changes of existing actors and an increase in the entry of new actors resulted in a transition to an electric vehicle industry space accompanied by new values.

• The Journal of Sustainable Design and Educational Environment Research
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• v.12 no.3
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• pp.11-25
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• 2013

This study aims on finding a direction of desirable space organization of future elementary school in Korea by analyzing current status of space organization of elementary school in Japan. In this study comparison and analysis of curriculum of Korea and Japan, facility standards on national level and standards of national subsidy, current status of number of schools and students, transition of changes in facility area of elementary school for last 10 years are included. In Korea and Japan each 7 elementary schools which were constructed after 2007 and are good in space organization and school planning are selected. The comparison and analysis of satisfaction level on physical educational conditions and facilities such as current status of space organization and how to use them are conducted in this study. The contents of analyzing space organization are 'entry and placement, outdoor space', 'space program' and 'phase structure and organization of unit space'.