• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1084-1085
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• 2007

This paper presents a vector control implementation for SPMSM(Surface-mounted Permanent Magnet Synchronous Motor) using dSPACE 1104 system and MATLAB/SIMULINK. SPMSM can be treated as a DC motor provided that currents of flux and torque component are controlled independently using vector control. Therefore various control algorithms for conventional DC motor control can be adopted to SPMSM. The system is designed to improve set-point tracking capability, fast response, and accuracy. In This paper, d-q equivalent modeling of PMSM is derived based on vector control theory. The PI controller is used for speed control and state feedback PI current control method is used for current control. For the implementation of high performance vector control system, dSPACE 1104 system is used. Simulations and experiments were carried out to examine validity of the proposed vector control implementation.

• Journal of Astronomy and Space Sciences
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• 제21권4호
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• pp.303-314
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• 2004

In this paper we report some properties of inner magnetospheric structure inferred from the T01_s code, one of the latest magnetospheric models by Tsyganenko. We have constructed three average storms representing moderate, strong, and severe intensity storms using 95 actual storms. The three storms are then modelled by the T01_s code to examine differences in magnetic structure among them. We find that the magnetic structure of intense storms is strikingly different from the normal structure. First, when the storm intensity is large, the field lines anchored at dayside longitudinal sectors become warped tailward to align to the solar wind direction. This is particularly so for the field lines anchored at the longitudinal sectors from postnoon through dusk. Also while for the moderate storm the equatorial magnetic field near geosynchronous altitude is found to be weakest near midnight sector, this depression region expands into even late afternoon sector during the severe storm. Accordingly the field line curvature radius at the equator in the premidnight geosynchronous region becomes unusually small, reaching down to a value less than 500 km. We attribute this strong depression and the dawn-dusk asymmetry to the combined effect from the enhanced tail current and the westward expansion/rotation of the partial ring current.

• 한국산학기술학회논문지
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• 제8권2호
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• pp.212-218
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• 2007

본 논문에서는 MATLAB/SIMULINK와 dSPACE DS1104를 이용하여 유도 전동기의 속도 센서리스 벡터제어를 구현하였다. 유도 전동기의 속도 센서리스 벡터제어의 운전특성을 개선하기 위하여 전압 모델 자속 추정방식과 전류 모델 자속 추정방식을 혼합한 자속 추정기 알고리즘을 도입하여 정밀도가 높은 개선된 자속 추정방식을 사용하였다. 또한 추정된 자속을 이용하여 회전자 속도를 추정하고 이를 유도전동기의 속도 제어에 사용하였다. 전체 시스템은 직접벡터제어 방식을 기반으로 일반적인 PI 제어기를 사용한 속도 제어기, 전류 제어기, 자속 제어기로 구성하였다. MATLAB/SIMULINK를 이용하여 블록다이어그램 방식으로 속도 센서리스 벡터제어 알고리즘을 구현하였고, dSPACE DS1104의 제어보드와 Real-Time-Interface(RTI)를 이용하여 실시간 제어를 수행하였다.

• 한국환경과학회지
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• 제31권7호
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• pp.543-553
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• 2022

The latest aerospace technology is important for the stable flight of a launch vehicle, but weather conditions on the day of launch are also one of the essential factors for successful launch campaign. If a launch vehicle is directly struck while preparing to take off from the launch pad on the day of launch or the electronic device are damaged by induced current during flight of the launch vehicle, this means launch failure and can lead to enormous national loss. Therefore, for a successful launch campaign, it is necessary to analyze the lightning detection characteristics of the Naro Space Center. In this study, the seasonal factors of the lightning that occurred over the Naro Space Center from 2003 to 2017, the influence of the polarity, and the correlation with the lightning intensity was confirmed. As a result, there was a high probability of intensive occurrence of multiple lightning strikes in summer, and a high proportion of positive (+) lightning strikes in winter. Lastly, in the distribution of the number of lightning strikes, an average of 2.0 to 2.5 negative (-) lightning strikes occurs in the coastal regions of the South and West Seas when one flash happens.

• 호남수학학술지
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• 제42권2호
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• pp.391-409
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• 2020

In the current paper, the intuitionistic fuzzy normed space version of Hyers-Ulam stability for multi-additive, multi-cubic and multi-additive-cubic mappings by using a fixed point method are studied. Moreover, a few corollaries corresponding to some known stability and hyperstability outcomes in intuitionistic fuzzy normed space are presented.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.207-210
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• 1998

Electrical properties such as space charge distribution and electrical conduction of XLPE/VLDPE blends were studied. When the VLDPE is blended, residual charge inside XLPE increases. In case of electrical conduction characteristics, there were no changes in electrical conduction mechanism, space charge limited conduction. XLPE/VLDPE blend including crosslinking coagent showed relatively small current density. It might be due to the carbonyl group in crosslinking coagent.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2007년도 한국우주과학회보 제16권1호
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• pp.73-73
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• 2007

• 교육시설 논문지
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• 제20권2호
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• pp.33-42
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• 2013

Due to the lack of available site in urban setting outdoor space in elementary schools are getting smaller and tend to be replaced by indoor spaces. Focusing on courtyard, piloti space and roof space, this study analyzed the current condition and usage of the outdoor spaces in the urban mini-schools based on the analysis of architectural drawing, interview, survey, and observation. Following issues are found for appropriate planning for outdoor spaces in the urban mini-schools. Firstly, roof space needs to be coordinated with the physical education and outdoor class curriculum and should be planned separately for quiet activities. Secondly, the piloti space should be planned as an independent space rather than a connection between classroom and outdoor space, with appropriate surveillance from teacher's space for the lower graders. Thirdly, courtyard space, typical space in urban mini school surrounded by densely arranged buildings, should be thermally controlled for outdoor class or resting with appropriate screen from noise to keep quiet atmosphere.

• 아동학회지
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• 제3권
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• pp.35-48
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• 1982

The purpose of this study is to investigate the Piaget's theory of the child's conception of space, which explains the stage of child's congnitive development. This thesis consists of 4 Chapters, including introduction, which examines the concept of space perception, and the development of arithmetic conception, and suggests the outline of this study. In the Chapter II, the brief history of topological Psychology, and the current situation of this theory has been explained. According to Piaget's theory of the conception of space, the child's development of the conception of space develops orderly three stages, that is to say, the stage of conception of space by the topological relations, the stage of projective conception of space, and finally the stage of the Euclidian, conception of space. Children's development of the conception of space continuously, and orderly has been made by these stages. Also, in this Chapter, Piaget's experiment about the development of child's conception of space has been explained. In the Chapter III, the children's conception of geometry has been examined. Here explains the development of space representation, and of seriation or classification. In the Chapter IV, some theories of the conception of space has been examined, and some points of view has been made as a conclusion.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.1035-1037
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• 2001

This paper presents an improved hys- teresis current control method for three-phase PWM power inverters using 3-level comparator. Hysteresis current controller using 3-level comparator has an advantage of constant switching frequency compared with conventional hysteresis current controller. However, this method has disadvantage that the longer sampling period, the larger current error because the switching is performed without considering current error magnitude of each phase. The proposed method improves the control performance by selecting the optimum switching pattern in which the magnitudes of current errors are considered introducing space vector concept. Simulation results using Matlab/Simulink show that the proposed control method reduces current error keeping the merit of previous hysteresis current control method.