• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.960-965
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• 2014

Transmission loss of specimen is calculated by measuring energy of incident and transmission and using reverberant room of large size. But normal measurement of transmission loss has trouble because it is actually demanded that large area and specimen of certain size is satisfied with condition of diffused sound field. Especially, in case of mechanical component, interested frequency band is mid-frequency band between 500 ~ 2k Hz, and it is used to be available to minimize a reverberation chamber under conditions satisfying acoustic one because production of specimen for transmission loss measurement has limit. But, as in semi-reverberation room, it is difficult to satisfy condition of diffuse sound field and modification factor is applied to complement that. Correction factor when measuring transmission loss using semi-reverberation chamber is required accuracy because it works as main factor determining reliability of reuslts on transmission loss. In this study, it is analyzed that an effect on correction factor based on varying materials and sizes of specimens in order to deduction of it. Also It is confirmed that applied by elicited correction factor with actual railway vehicle's floor has reliability.

• Applied Microscopy
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• 제22권1호
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• pp.55-69
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• 1992

Viral disease incidence in the peanut fields at Iri, Kochang, Iksan and Puan in Chonbuk province was 0.93% on July and 8.46% on August in 1991. The causal pathogen was identified as peanut stripe virus (PStV) by the results of host plant reaction, immunological assay and observation of virus particles. Seed transmission rates of collected seeds from diseased plants ranged from 12.9 to 14.8% at peanut fields. PStV transmission was higher in small than in large seeds. Seed transmission of PStV was correlated with the age of the plant when inoculated; infection of young plants resulted in more seed transmission than did infection of old plants. Seed transmission of PStV was correlated with pod formation stages when inoculated at the 45th day after sowing; formed seeds for 2 weeks after inoculation resulted in more seed transmission than did formed seeds after 4 weeks. In seed transmission, this causal virus was moved to embryo and cotyledon through gynophore, pod, and funicle from leaves.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.107-108
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• 2007

Overhead transmission lines are completely exposed to the environment. This causes faults in transmission lines due to natural environmental conditions. In some cases, transmission towers are damaged by typhoons and snow, as well as sleet on the transmission lines. It takes a lot of time to repair the damaged towers. For emergency restoration purposes, steel poles are installed to temporarily supply power. Before 2003, emergency restoration steel poles were made of angled steel, which required a large number of beams, bolts, etc. In addition, the foundation of the steel pole and ground wire was constructed using excavation and burial methods, therefore it required a lot of manpower and time to construct temporary transmission lines. In September 2003, typhoon Maemi, whose maximum wind speed was 60m/s, hit Korea. 'Maemi' destroyed transmission lines in the Busan and Geojea area, causing long blackouts. To reduce the recovery time to the damaged transmission lines, self-build based emergency towers were developed. self-build based emergency towers reduced recovery time from 24 hours to 4 hours or less. However, the self-build based emergency tower had no arms, so the temporary transmission lines could only be constructed without curves in line routes. In this paper, solving these self-build based emergency tower limitations, using insulated arms(designed for use with the self-build based emergency tower), shall be explained.

• 한국측량학회지
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• 제37권2호
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• pp.63-70
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• 2019

Electric transmission towers are facilities to transport electrical power from a plant to an electrical substation. The towers are connected using wires considering the wire tension and the clearance from the ground or nearby objects. The wires are installed on a rights-of-way that is a strip of land used by electrical utilities to maintain the transmission line facilities. Trees and plants around transmission lines must be managed to keep the operation of these lines safe and reliable. This study proposed the use of a low-cost drone photogrammetry for the transmission line rights-of-way mapping. Aerial photogrammetry is carried out to generate a dense point cloud around the transmission lines from which a DSM (Digital Surface Model) and DTM (Digital Terrain Model) are created. The lines and nearby objects are separated using nDSM (normalized Digital Surface Model) and the noises are suppressed in the multiple image space for the geospatial analysis. The experimental result with drone images over two spans of transmission lines on a mountain area showed that the proposed method successfully generate the rights-of-way map with hazard nearby objects.

• 전기전자학회논문지
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• 제11권4호
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• pp.239-246
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• 2007

한국 전력 계통의 가장 큰 문제점은 수도권의 부하 집중으로서, 서울과 경기도를 비롯한 수도권의 부하량은 전체 전력 소비량의 약 40%를 차지하는 반면 이들 지역의 발전량은 전체 전력 발전량의 약 16%에 불과하다. 이러한 수도권의 전력 수급에서의 불균형은 수도권이 아닌 다른 지역에서의 전력 전송을 필요로 한다. 이러한 장거리 전력 전송은 유효 전력에서의 손실 증대, 국지적인 무효 전력 불균형으로 인한 송전 용량 제한, 고장 용량의 증대 등을 일으키게 된다. 이를 해결하기 위해 고려할 수 있는 가장 간단한 방법은 수도권 내의 발전소 신설 또는 대용량 송전 선로의 추가 설치이다. 그러나 수도권은 과도한 인적 물적 자원의 밀집으로 인하여 대규모 발전소 및 송변전 설비의 건설을 위한 토지 조달 등에 어려움이 있고 또한 인구 밀집 지역에서는 공해와 같은 환경적 문제와 혐오 시설 기피 등의 사회적 문제로 인하여 현실적으로 발전소 또는 송 변전 설비의 건설은 불가능한 실정이다. 따라서 대규모 설비의 건설에 의한 문제 해결 보다는 기존 설비의 활용도를 증대시키는 방향으로의 접근법이 요구된다. 본 연구에서는 기존 송전 선로의 활용도 증대를 고려한 HVDC의 적용 방안을 개발하고자 하며, 이를 위한 시뮬레이션 모델의 개발 및 해석을 다루고 있다.

• 한국멀티미디어학회논문지
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• 제11권7호
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• pp.1025-1034
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• 2008

본 논문은 모바일 디바이스에 GML을 효율적으로 공급하고 가시화하기 위한 맵 분할 및 캐싱 기법을 제안하고, 이를 적용한 GridGML을 구현한다. GridGML은 GML의 가장 큰 단점인 가중성을 극복하기 위해 GML 속성들 중 맵 가시화 핵심 부분만을 추출 및 클래스 객체로 경량화 한다. GridGML은 모바일 디바이스에 실시간으로 맵을 공급하고 가시화하기 위해 모바일 디바이스 가시영역을 기준으로 분할 관리하며, 분할 영역은 전송상의 이점을 위해 바이트화 하여 전송한다. 그리고 모바일 디바이스에서는 수신된 분할영역을 조합한 후 모바일 디바이스에서 표현하는 영역에 따라 4개의 가시영역으로 재분할 및 가시화를 한다. 또한, 자원의 효율적 운영을 위해 이전에 전송받은 맵의 중복성을 고려한 캐싱 알고리즘을 적용하여 관리한다. 맵의 객체 밀집 지역에 대해서는 전송시간의 지연을 방지하기 위해 적응적 맵 분할 메커니즘을 제안하여 전송시간을 일정함을 유지한다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.97-100
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• 2007

This study deals with the sound insulation performance of the damping sheet, which is widely used in a train. The wall of train is assumed to be a plate made of steel and two damping sheets. In case of damping sheet only, the sound transmission loss follows the mass law. If a steel plate is attached to damping sheet, the transmission loss is found to be higher than single of only steel plate, as we can anticipated, about $3{\sim}5$ dB. This is very well known consequence that is because the density of area increases. However, the increase of the transmission loss is not higher than what we can expect by the mass law. That's because the steel is perfectly blocked from the transmission of the air ; There is no defect in that material.

• 전기학회논문지P
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• 제64권4호
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• pp.291-296
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• 2015

Transmission line is exposed to a large area, and then faults are likely to occur than the other component of power system. When a fault occurs on a transmission line, fault locator helps fast recovery of power supply on power system. This paper deals with the design of a digital fault locator for improvement accuracy of the fault distance estimation and a fault occurrence position for transmission line. The algorithm of a fault locator uses a DC offset removal filter and DFT filter. The algorithm utilizes a fault data of GPS time synchronized. The computed fault information is transmitted to the other side substation through communication. The digital fault locator includes MPU module, ADPU module, SIU module, and a power module. The MMI firmware and software of the fault locator was implemented.

• 한국전자거래학회지
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• 제4권2호
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• pp.41-58
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• 1999

This paper is a study on a model of economic value of transmission speed of Internet Commerce. For this research, this paper searches the factors that influence the transmission speed of Internet and suggests the model for measurement of economic value. The model adopted in this research is CVM(contingent valuation method) using in environment economics and the research area in this paper is concentrated on Internet-based Electronic Commerce. For this purpose, this paper suggests econometrics model that measures customer's payment intention for transmission speed of Internet. This model can be used as the basic tool of feasibility of investment analysis and reasonable pricing on Internet service. For the more, it will be followed empirical study and more careful comprehension for objective validity of this study.

• 한국군사과학기술학회지
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• 제11권5호
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• pp.42-48
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• 2008

In this paper, we have introduced a Code Division Multiplexing transmission method which is similar to OFDM and analyze ECCM performances. We have verified CDM transmission method has a good LPI performance and a feasible ECCM performance. This capability could be useful for reduction of RF interference which occurs when many equipments operate densely in small area. The equipment that uses CDM transmission method supports variable transmission rate and order-wire effectively and conveniently to user. This CDM method has similar ECCM performance comparing to serial DS method. CDM method has good multi-path signal processing capability and could be useful for mobile communication environment.