• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2149-2151
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• 1999

This paper describes the impulse response characteristics of the grounding systems in power utility system. Several regulations regarding to electric power equipments, services and managements require that the groundings of class 1 ($E_1$) and class 2 ($E_2$) must be connected at the common point in grounding systems. In addition, the grounding for arrester ($E_{LA}$), which belongs to the grounding of class 1, should be connected at the same point. However, there is no method and position of common-connection at anywhere. In this work, when the impulse current was injected through the grounding conductor for arrester, the investigations measuring and analyzing potential rises induced at the common connection point and other grounding conductors were conducted. The experiments were carried out in the conditions of the grounding conductor of 25m long and the near or remote common connection from ground electrode. The lightning impulse current was applied so as to simulate the on-set of arrester due to lightning and/or switching surges.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.6
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• pp.605-612
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• 2011

In this paper, we designed detachable T-DMB receiver antenna on the windshield of the car. Designed antenna is composed of only copper and feeders. To escape completely from driver's sight, it exists edging of windshield. Proposed antenna by considering body of properties and characteristics of the antenna input impedance have T-DMB frequency band(174~216 MHz). Proposed flexible antenna with Common Mode Stub is satisfied characteristics less than -5 dB antenna input return loss regardless of installation position on windshield.

• Korean Journal of Plant Resources
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• v.25 no.3
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• pp.357-362
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• 2012

The potential cultivation of buckwheat species in Luang Prabang region, Lao PDR where the species has not been naturally grown and not traditionally utilized was studied to introduce buckwheat as a new agricultural material, especially for food and medicine. The growth of Tartary buckwheat species was higher than common buckwheat showing 2.3 fold of plant height compared to common buckwheat. Number of flower per plant in Tartary buckwheat (731) was three fold higher than common buckwheat (244). Dry weight per plant was respectively 1.7 g in Suwon No. 1, 2.6 g in Suwon No. 2, and 1.4 g in KW45. The rate average of seed setting was similar between common buckwheat (41 to 46 %) and Tartary buckwheat (44%). Total seed yield of Tartary buckwheat (184 kg/10 a) in 10a could be estimated to be higher than that of common buckwheat (108 kg/10 a).

• Nuclear Engineering and Technology
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• v.15 no.4
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• pp.229-235
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• 1983

Common Mode Failures (CMFs) have been a serious concern in the nuclear power plant. There is a broad category of the failure mechanisms that can cause common mode failures. This paper is a theoretical investigation of the CMFs on the unavailability of the redundant system. It is assumed that the total CMFs consist of the potential CMFs and the dependent human error CMFs. As the human error dependence is higher, the total CMFs are more effected by the dependent human error. If the human error dependence is lower, the system unavailability strongly depends on the potential CMFs, rather than the mechanical failure or the dependent human error. And it is shown that the total CMFs are dominant factor to the unavailability of the redundant system.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.9
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• pp.509-514
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• 2002

The aim of this research is to find out how the common earth network affects the level of the traction return current in the $2{\times}25 kV$ Power Supply System. The traction return current plays a significant role in the operation of the facilities near the rails. It is shown that the common earth network in the $2{\times}25 kV$ power supply system not only minimizes the level of the traction return current, but also increases the safety of the working crew on the railways. In order to determine the relationship between common earth network and the traction return current, we investigated the earth system of the Gyongbu High Speed Line that is constructed following the SNCF regulations. We carried out the field test in the Osong station. The results of the test show that the common earth network minimizes the effect of the traction return current. We also find that the simulated results are very similar to the test results. We concluded that the results of the test can be applied for the rest of the Gyongbu High Speed Line under construction.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.1023-1033
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• 2014

In this paper, performance improved hole-filling algorithm which includes the boundary noise removing pre-process that can be used for an arbitrary virtual view synthesis has been proposed. Boundary noise occurs due to the boundary mismatch between depth and texture images during the 3D warping process and it usually causes unusual defects in a generated virtual view. Common-hole is impossible to recover by using only a given original view as a reference and most of the conventional algorithms generate unnatural views that include constrained parts of the texture. To remove the boundary noise, we first find occlusion regions and expand these regions to the common-hole region in the synthesized view. Then, we fill the common-hole using the spiral weighted average algorithm and the gradient searching algorithm. The spiral weighted average algorithm keeps the boundary of each object well by using depth information and the gradient searching algorithm preserves the details. We tried to combine strong points of both the spiral weighted average algorithm and the gradient searching algorithm. We also tried to reduce the flickering defect that exists around the filled common-hole region by using a probability mask. The experimental results show that the proposed algorithm performs much better than the conventional algorithms.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1515-1517
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• 2005

In this paper, we represent both occurrence reason of Surge-voltage and Leakage-current of AC drive system which is operated by Voltage-type PWM Inverter. It generates a compensating voltage which has the same amplitude as, but the opposite phase to, the common-mode voltage produced by the PWM inverter. The compensating voltage is superimposed on the inverter output by a common-mode transformer. As a result, the common-mode voltage applied to the load is canceled completely. The design method of the active common-mode noise canceler is also presented in detail. Therefore, we try to describe the method controling both of them and all of the proprieties are proved by our experiment.

• Journal of Chest Surgery
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• v.5 no.2
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• pp.113-124
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• 1972

Clinical observations were performed on 150 cases of chest trauma, those were admitted and treated at the Department of Surgery, Korea University Woosok Hospital, during the past 8 years period from August 1965 to August 1972. 1. The ratio of male to female patient of chest trauma was 3.4:1 in male predominence and age from 20 to 50 occupied 62% of the total cases. 2. The most common cause of chest trauma was traffic accident in this series. Eighty-one cases[54%] were injured by traffic accident and total cases due to blunt trauma [non-penetrating injury] were 113 cases[75.4%]including the cases with traffic accident, and remaining 37 cases[24.6%] were due to penetrating injury including 25[16.6%] cases of stab wounds. 3. Hemopneumothorax were observed in 645/[96 cases] of the total cases, and etiologic distribution revealed 78.1% due to non-penetrating trauma and 20.8% due to penetrating injury. 4. Rib fracture was found in 50% of cases. Common injuries associated with rib fracture were lung, brain and liver. 5. Most common symptom was chest pain and respiratory difficulty, and common sign associated with chest injury was decreased respiratory sound and subcutaneous emphysema. 6. Conservative non-operative treatment was performed in 94 cases[62.6%] and 56 cases [37.4%] were treated with operative treatment including 31 cases[20.6%] with open thoracotomy. 7. Overall mortality was 9.3%[14 cases] and most common causes of death were due to brain edema,asphyxia and shock.

• Korean Journal of Organic Agriculture
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• v.26 no.4
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• pp.745-757
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• 2018

We analyzed the nuclear ribosomal internal transcribed spacer (ITS) sequence of common buckwheat, Fagopyrum esculentum and tartary buckwheat, F. tataricum. The diversity of the nucleotides and haplotypes, Tajima's D, and Fu's Fs was analyzed and compared among the varieties of common buckwheat and tartary buckwheat. The diversity of nucleotides and haplotypes indicated that the buckwheat populations had undergone rapid population expansion but D and Fs did not support their expansion statistically. The phylogenetic analysis of ITS sequences did not clearly establish the phylogenetic relationships between the varieties of common buckwheat. The In/Del sequence of ITS-1 region could, therefore, be used as a DNA marker to distinguish raw or manufactured products derived from common buckwheat and tartary buckwheat.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.3
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• pp.167-174
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• 2021

Computational Fluid Dynamics (CFD) was performed under low-speed wind tunnel test conditions using a 29.7% scale model of the NASA common research model. A wind tunnel test was conducted to measure the aerodynamic coefficient of the CRM with Belly sting model support configuration at a low Reynolds number of 0.3×106 and it was compared with the aerodynamic coefficient of CFD analysis. In order to verify the validation of the analysis, a computational analysis under the conditions of the advance research was performed and compared. The interference effect of the Belly sting model support affected not only the fuselage but also the main and tail wings.