• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.123_124
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• 2009

현재, 제주계통의 풍력설비 한계용량은 120MW로 2007년 12월 이후 풍력발전 사업허가가 중지된 상황이다. 2011년 12월 제2연계선 준공과 함께 풍력설비 한계용량이 대폭 상향될 전망이지만, 정부의 강력한 녹색성장 추진의지로 국산풍력발전기가 개발되면서, 풍력발전기 성능 실증시험지로서의 최적지인 제주지역에 이를 수용하기 위한 당장의 방안마련이 시급한 실정이다. 본 논문에서는 현재 운영 중인 풍력발전설비와 건설 중인 풍력발전설비의 용량을 알아보고, 제2연계선 준공이전인 2010년, 2011년의 추가 풍력발전기의 건설허가 수용가능성을 수요 전망과 운영발전계획을 통하여 검토해보고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.3013-3022
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• 2013

Satisfying the large car impact condition of the high level SB5-B for "SMART Highway" longitudinal barriers, the possibility of increase of the small car impact velocity from 120km/h to 130km/h was investigated. Through computer simulation using input parameters calibrated to full-scale crash test results, various longitudinal semi-rigid barrier models were improved such that for the small car impact speed of 120km/h the change of longitudinal and transverse velocities of the impact vehicle can satisfy the THIV limit. The barrier model determined through this process satisfied the performance assessment criteria for SB5-B impact conditions. Varying the wing angle of slip block-outs of the passed barrier model, the possibility of increase of the small car impact velocity was investigated by FEA and a full-scale crash test was conducted. It has been shown that the possibility to increase the small car impact speed to 130km/h is high if the test facility condition for 130km/h impact velocity is better equipped.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.3
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• pp.1001-1010
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• 1991

본 연구에서는 천이유동의 존재를 밝히고 천이영역과 경사각의 관계, 유동 및 열전달특성을 구명하고자 한다.이를 위해 유한차분방법(FDM)으로 수치해석하고 실 험결과와 비교, 검토하였다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.3
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• pp.175-181
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• 2003

In this reseach, a seepage test is carried out for three kinds of soil using a upward seepage equipment. Reliability about the existing method of pipining investigation were verified making an estimate of the critical velocity, the critical hydraulic gradient, and hydraulic conductivity and so on. Also, sensitive analyses were carried out using Plaxis that is FEM Program about design factors of scour. The height of core had a big infulence on the hydraulic gradient of the embankment's lower part in the result of sensitive anaylsis. Also, second only to the height of core, and the slope of embankment, the width of crest had influence on scour. However, the change of hydraulic gradient in the effluent gateway had a little influence on the crest width of core. Using these results of sensitive analysis on designing, hydraulic gradient in the effluence gateway turned out to be reducing by altering design factors that change of sensitiveness is big, in case of the hydraulic gradient bigger than the standard hydraulic gradient.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.4
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• pp.101-109
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• 2008

Automated rainfall warning system is a facility to prevent casualties who were recreating in the down stream region with operating lead broadcasting or signaling warning automatically when torrential rainfall occurs in mountainous area. But standard of conventional warning does not consider the characteristics of basin, and warning signal. Evacuation signal 1 and evacuation signal 2 are uniformly signaled when the 10minute moving total of observed rainfall is higher than 4 mm, 6 mm, and 8 mm respectively. therefore, local governments and relative agencies had re-established the standard of warning by analyzing the risk water level, critical discharge and reference rainfall, which are considering the characteristics of basin. In this study the standard of conventional and re-established warning of weolseong basin, which is available to acquire a real rainfall. There are analyzed by considering the risk water level, critcal discharge and reference rainfall. Also this study compares rainfall of conventional and re-established warning standard and indentifies problems by analyzing adequacy of rainfall estimation for warning and proposes alternative. The standard of conventional warning which investigates with the converted rainfall(unit of a minute) issued too many alarm. The re-established standard upward has the necessity which will be regulated about the alarm announcement number of times. Considers the safety, upward regulation of alarm standard rainfall is a necessity which will be prudent.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.5 no.2
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• pp.66-75
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• 1993

Hydraulic experiments were performed in order to gain an insight into the quantitative differences between the perforated wall caisson and its solid wall counterpart in the local pressure distribution and caisson stability. The results showed that the wave forces acting on local walls were smaller in the perforated wall caisson than in the solid wall caisson. For the caisson stability, the critical weights of the perforated wall caisson also turned out to be smaller than those of the solid wall caisson. The Phenomenon was attributed to the dual effects inherent to the perforated wall caisson, which are the decrease of total horizontal force and the phase difference between the total horizontal and vertical forces.

• The Journal of Information Technology
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• v.3 no.2
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• pp.87-95
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• 2000

This paper studies on method about construction and design of two-way message system to overcome limit of one-way pager system. Method of two-way system construction is studied on using the present one-way pager system and configure system. Forward-link of proposed method is using the present one-way pager system. And Reverse-link of proposed method is used TRS and Beacon on pager. CTI(Computer Telephony Integration) is used to Call processing

• Proceedings of the Korean Information Science Society Conference
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• 2011.06c
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• pp.37-40
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• 2011

계층적 색인 구조는 대용량의 다차원 데이터에 대한 범위질의를 가장 효율적으로 처리하는 색인 구조이다. 계층적 색인 구조에서 범위질의의 속도를 향상시키기 위해서 색인 구조의 구성 시 발생하는 인접노드간의 겹치는 영역을 줄이는 기법들과 다량의 데이터를 한 번에 읽어 상향식 방식으로 색인 구조의 공간 활용도를 증가시키는 벌크 로딩 기법들이 제안되었다. 하지만 CPU기반에서 개별의 노드들을 순차적으로 질의처리 하는 계층적 색인 구조는 공간 활용도의 증가와 노드 간의 중첩 영역을 줄이는 것만으로는 질의 처리 성능 향상에 한계가 있다. 따라서 본 논문에서는 기존의 CPU기반 계층적 색인 구조 중의 대표적인 예인 R-tree의 저장 구조를 GPU 메모리에 적합하도록 변경을 하였다. 또한 기존 CPU기반 계층적 색인 구조의 순차적인 노드 검색을 GPU를 이용해 병렬적으로 노드를 검사하여 성능을 향상시켰다. 이와 같은 방식으로 질의 영역의 크기에 따라서 성능 향상정도가 다르지만 최대 100배 이상의 성능을 향상시켰다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.5
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• pp.435-448
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• 2024

Liquefaction of the ground caused by earthquakes results in significant damage to underground structures such as tunnels, pipelines, manholes, and underground tanks. The uplift of underground structures due to liquefaction has been identified as a major cause of this damage. However, current design practices have not adequately considered the upward displacement of underground structures. This paper proposes an analytical solution based on the limit equilibrium method for cut-and-cover tunnels. Using this solution, a sensitivity analysis was performed on soil cover height, liquefaction depth, ground improvement, and ledge. It was confirmed that the contribution of each factor to the safety factor can be reasonably derived through changes in the safety factor. Although there are still many assumptions and uncertainties that need to be reviewed for their appropriateness, a conservative approach appears to mitigate a significant portion of these uncertainties. This study is meaningful as a stability evaluation method considering the uplift behavior characteristics of underground structures.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.9A
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• pp.749-754
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• 2005

It is well-known that mobile communication systems are usually limited in their performance and capacity by three major impairments, which are multipath fading, delay spread and co-channel interference (CCI). OFDMA (OFDM-FDMA) system can cope with the multipath fading and delay spread easily due to the beneficial properties of OmM technology. Though OFDMA scheme avoids intra-cell interference using the orthogonality among subcarriers, the scheme contains difficulty of reducing co-channel interference. Therefore, in this paper, adaptive antenna techniques are deployed into OFDMA/TDD system to minimize the co-channel interference induced by adjacent cells and to enhance the uplink performance. For the improvement of downlink performance, we apply TxAA (Transmit Adaptive Array), a kind of transmit diversity technique, utilizing preamble symbols for training antenna may into OFDMA/TDD transmitter side. Simulation results show that the uplink and downlink performance under multipath Rayleigh fading channel improved 9dB and 7dB each compared with the case of single antenna system at target BER $10^{-3}$ .