• ETRI Journal
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• 제17권3호
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• pp.45-63
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• 1995

This paper proposes an algorithm to improve the correlation between giga-hertz transverse electromagnetic (GTEM) cell and open area test site (OATS). It is based on the dipole modeling process of an unknown source object in a GTEM cell and on the evaluation of the approximate far field equations correlated with measured GTEM powers at output port of the GTEM cell. In this algorithm, the relative phase differences between dipole moments play an important part in modeling the test object as a set of dipoles and offer stable calculation of emission values. The radiated emission test using this algorithm requires fifteen orientations of equipment under test, but the increased orientations as compared with the previous method have little effect on the time needed for testing. Radiation from a notebook computer has been tested for statistical analysis of the correlation between GTEM data and OATS data. The emission test results of the notebook computer show that the mean, the standard deviation, and the correlation coefficient are -0.62, 1.99, and +0.85, respectively. These figures indicate that this algorithm provides improved accuracy in the measurement of electromagnetic emissions over the previous method.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2001년도 유체기계 연구개발 발표회 논문집
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• pp.419-424
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• 2001

TCV(Temperature control valve by pressure compensation) controls temperature constantly, when it is sending steam or high temperature water to heating device of heat exchanger. For designing TCV, the ratio of piston and hole diameters is one of the important design parameters. Numerical analysis is carried out to elucidate the flow characteristics in the TCV with different port areas of cold and hot waters, using the k-$\epsilon$ turbulence model and Cartesian cut-cell method. Numerical results show that the exit flow rate is mainly affected by pressure distribution in the piston.

• 한국항해학회지
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• 제20권3호
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• pp.107-115
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• 1996

With the rapid advance of electronic equipments and the frequent, use of them, the electromagnetic environments including EMC or EMI problems are very complicated. The radiation of electromagnetic waves from electronic equipments has strictly been controlled by the authorities concerned from many years ago. Though it is the most proper to test EMI or EMC in the open area test site, we have used the anechoic chamber in place of the test site because of its various restrictions. To achieve the purpose, in this paper, the performances of a few anechoic chambers according to absorbing materials are analyzed for horizontal and vertical polarizations respectively. Furthermore, the calculated and the measured site attenuations in semi-anechoic chamber made with ferrite grid are compared. The obtained results are to be valuable for designing an anechoic chamber.

• 한국항해학회지
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• 제14권1호
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• pp.39-55
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• 1990

Numerical model simulations are conducted for the evaluation of the water level variation in and out of the harbor due to the development and improvement of a harbor. The method used for the numerical analysis is the hybrid element method which includes energy dissipation due to imperfect reflection at the shore boundary and friction at the bottom. The model also includes the radiation condition on the open boundary by the analytic formulation and is applied to a real harbor, Guryongpo Harbor at the east coast of Korea. The result of experiment within the selected wave frequency band shows that the amplification factor out of the harbor is more than 2.0 at 32 sec period and strong responses near 20 sec, 25 sec, 54 sec periods in the harbor. Moreover, simulation results indicate that other longer wave periods affect to the variation of water level and horizontal water particle velocity exist. Thus, it seems to be necessary to modify the planform and the design of the harbor structures for the coming development.

• 한국항해학회지
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• 제21권4호
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• pp.29-38
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• 1997

Because of the result of a large use of electronic equipments, the occupation density of microwave frequency band is highly increased, and electromagnetic environment is getting more seriously bad. It is sometimes reported that electronic machines are not normally operated on account of the influence of undesired electromagnetic wave, which often gives fatal blow to even human life and thus becomes serious social problems. OATS(Open Area Test Site) is principally used to measure EMI or examine elelctromagnetic emission. Because of various restrictions we often build semi-anechoic chamber which has the function of OATS to measure EMI or EMS other than OATS. If the difference of the site attenuation between semi-anechoic chamber and OATS is within ${\pm}3dB$, the semi-anechoic chamber is recognized as adequate facility to measure EMI or EMS. Accordingly authors evaluate and analyze site attenuation due to absorbent materials, polarization, mutual coupling effects, etc. The calculated and the measured site attenuation in semi-anechoic chamber are compared. As a result good agreement is obtained.

• 한국항해학회지
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• 제19권1호
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• pp.9-16
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• 1995

We are confronted with the serious EMI(electromagnetic interference) problems in company with the development of electronic equipments. Accordingly it is also required to construct some anechoic chambers for EMI measurement. Furthermore it is very important to evaluate the chamber characteristics in advance of its construction. For that purpose we have analyzed the characteristics by computer simulation in base on the image method, and compared the results with the measured ones. In case of 3-meter method as a result, the curved line of height pattern of open site varies similarly as that of height pattern of anechoic chamber. When we measure the electromagnetic strength and can get the height pattern curves by frequencies, we utilized it effectively because we can protect instrumental errors in measurement. On the other hand, there is a little difference in site attenuation above 700MHz. When the ferrite grid was used however, the calculated values agree well with the measured values up to 1000MHz with the exception of 30-40 MHz range. The reason is that we don't consider the antenna coupling in the low frequencies of 30-100MHz range.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.82.6-82
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• 2001

This paper presents the control X-Y table being the precise movement by point-to-point in the x-y plane. The dual modulus technique is used for our system to control the frequency of pulse supplied to the motors. Such technique is used to stop motor of both axes accurately as the desired target point in the same period. Both motors are stepping motor. To Improve steps per revolution, we employ ministep form to drive motors. In system, personal computer, using parallel port, is used for computing algorithm in open-loop form to control motors. In experiment, our system applies on the X-Y table for drawing to test system performance.

• 대한건축학회논문집:계획계
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• 제35권11호
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• pp.3-12
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• 2019

This study is concerning on the Space Modification and Facilities Characteristics of the Busan Exported-cow Quarantine Service Station(1909) before and afrter on the limits of 1945. For on this purpose, National Archives & Records Service(DJB0002115), field survey, documents records and modern aged map were analysised by each period phases, 1909, 1924, 1946, 1951 and now so on. At results on this study is the discovery on the meaning of this placeness, Space Modification and Facilities Characteristics till now before the 120 years ago. And this place has been comprehenive meaning unique dwelling form and almost rarely existing refuge village of Korea War in Korea.

• 도시과학
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• 제11권1호
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• pp.59-68
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• 2022

This study, the meaning of historical and cultural content utilization in urban regeneration was examined and in the process, the causal relationship between each variable was verified through path analysis among physical, cultural, social, and economic factors. The purpose of this study is to find the main variables of historical and cultural content urban regeneration projects in which the moderating effect of economic factors and demographic characteristics, which are mediating effects, have a significant effect on resident participation and life satisfaction of local residents. Furthermore, by presenting a more integrated and effective urban regeneration policy plan, it is intended to ultimately contribute to the vitalization and direction of urban regeneration.

• 반도체디스플레이기술학회지
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• 제22권2호
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• pp.11-16
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• 2023

EtherCAT is an Ethernet-based fieldbus system standardized in IEC 61158 and SEMI, and widely used in the fields of factory automation, semiconductor equipment and robotics. In this paper, without operating system, we have implemented an EtherCAT master with an open source EtherCAT master stack SOEM on STM32 Nucleo-144 board with an STM32F767 microcontroller. And its jitter performance has been evaluated at the output of the network port to include all the effects of the entire system in the results. The results show that the implemented EtherCAT master has precise control performance for control frequencies from 1KHz to 8KHz and relatively superior jitter performance compared to the EtherCAT masters with real-time patched Linux operating system.