• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.843-848
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• 2011

Planning and construction of railway for high speed trains up to 400 km/h are recently driven in Korea. High speed train is one of the environment-friendly fastest mass transportation means but its noise generated by rolling, traction and aerodynamic mechanism can cause public complaints of residents nearby railways. To cost-effectively prevent the troublesome noise in a railway planning stage, the rational railway noise prediction method considering the characteristics of trains as well as railway structures should be required but it is difficult to find authentic methods for Korean high speed trains such as KTX and KTX-II. In this study, we propose a framework of our own railway noise prediction model emitted by Korean high speed trains over 250 km/h based on the recent research results carried out in EU countries. The model considers railway sound power level using several point sources distributed in heights as well as tracks, whose detail speed- and frequency-dependent emission characteristics of Korean high speed trains should be determined in near future by measurement or numerical analysis. The attenuation during propagation outdoors is calculated by the well-known ISO 9613-2 and auxiliary methods to consider undulated terrain and wind effect.

• 지구물리
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• 제8권3호
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• pp.131-135
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• 2005

독도 주변 해역에는 최대 3 km 두께의 퇴적층이 화산활동에 의해 변형된 기반암 위에 집적되어 있다. 지질구조로는 기반암에 분지 형성 시기에 생성된 정단층이 우세하게 나타나는 반면, 퇴적층 내에는 화산활동에 의한 정단층, 화산돔 및 화산수평맥 등이 우세하게 관찰된다. 이들의 각 시대별 분포로부터 울릉분지에서는 북동쪽(독도 방향)으로 가면서 화산활동이 활발했음을 알 수 있다. 퇴적층이 집적되기 전인 초․중기 마이오세 이전에 조사지역은 확장성 지각변형이 우세했으며, 후기 마이오세 말기 이후에는 지하내부의 화산체 활동 및 분지의 침강 등의 지구조 운동에 의해 변형되어 현재와 같은 복잡한 구조의 분지를 형성하였다.

• 한국항공우주학회지
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• 제45권5호
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• pp.386-392
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• 2017

본 논문에서는 700 km 고도의 태양동기궤도 진입을 목표로 하는 3단형 위성발사체에 있어서, 여러 오차 요인들로 인한 성능 오차를 보상하면서 목표 궤도에 정확히 투입시키는데 필요한 비행성능여유에 대해서 살펴보았다. 우선 궤도 투입 오차에 영향을 끼치는 다양한 오차 요인들과 각 오차 요인의 분산을 정의하였다. 이를 토대로 각 오차 요인의 영향을 독립적으로 고려할 수 있는 장점이 있는 민감도 분석을 ${\pm}3{\sigma}$ 분산 조건에 대해서 수행하였다. 여기에 여러 오차 요인에 의한 영향을 종합적으로 고려할 수 있는 Monte Carlo 분석 방법을 적용해서도 요구 추진제를 계산하였다. 결과적으로 두 방법을 통해 얻어진 비행성능여유를 비교했으며, 유사한 수치가 도출됨을 확인하였다.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2005년도 공동학술대회 논문집
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• pp.145-150
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• 2005

독도 주변 해역에는 최대 3 km 두께의 퇴적층이 화산활동에 의해 변형된 기반암 위에 집적되어 있다. 지질구조로는 기반암에 분지 형성 시기에 생성된 정단층이 우세하게 나타나는 반면, 퇴적층 내에는 화산활동에 의한 정단층, 화산돔 및 화산수평맥 등이 우세하게 관찰된다. 이들의 각 시대별 분포로부터 울릉분지에서는 북동쪽(독도 방향)으로 가면서 화산활동이 활발했음을 알 수 있다. 퇴적층이 집적되기 전인 초${\cdot}$중기 마이오세 이전에 조사지역은 확장성 지각변형이 우세했으며, 후기 마이오세 말기 이후에는 지하내부의 화산체 활동 및 분지의 침강 등의 지구조 운동에 의해 변형되어 현재와 같은 복잡한 구조의 분지를 형성하였다.

• 자원환경지질
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• 제43권5호
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• pp.429-441
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• 2010

호주 Yilgarn Craton의 동부 Laverton Tectonic Zone에 위치하는 Sunrise Dam 금광은 서호주에서 지난 10년간 두번째로 가장 많은 금을 생산한 광산이다. 광상 주변의 지질은 화산암류와 이들의 상부에 산출하는 저탁 퇴적암류 그리고 이들을 관입하여 산출하는 시생대 및 원생대 석영섬록암 및 암맥류 등으로 구성된다. 이들 암석들은 북북동 방향의 비대칭 Spartan 배사를 이루고 있으며, 광상은 본 배사의 서쪽 날개부에 발달된 북동-남서 방향의 전단대를 따라 배태된 20여개의 광체로 구성되어 있다. 본 광상은 광물조합 등에 의하여 확실하게 구분되는 5개의 열수광화시기 ($D_1$, $D_2$, $D_3$, $D_4a$, $D_4b$)로 구분된다. 이들 열수광화시기 중 금 광화작용이 가장 우세하게 진행된 시기는 $D_4a$열수광화기이며, $D_4b$열수광화기에 그 다음으로 우세한 금 광화작용이 야기되었다. 이들 열수광화시기의 금 광화작용은 주로 황철석 및 사면동석의 침전과 밀접하게 관련되어 있다.

• 한국농공학회논문집
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• 제60권5호
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• pp.135-147
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• 2018

The objective of this study was to analyze the characteristics of combined 1D/2D inundation simulation of riverside farmland using the Hydrologic Engineering Center - River Analysis System (HEC-RAS). We compared and analyzed inundation simulation results between 1D and combined 1D/2D hydraulic simulation using HEC-RAS. Calibration and validation of stream stage were performed using three rainfall events. The coefficient of determination ($R^2$) and root mean square error (RMSE) between simulated and observed stream stage were 0.935 - 0.957 and 0.250 m - 0.283 m in calibration and validation, respectively. The inundation area showed no significant difference in 1D and combined 1D/2D simulation ($8.48km^2$ in 1D simulation, $8.75km^2$ in combined 1D/2D simulation). The average inundation depth by 1D simulation was 1.4 m deeper than combined 1D/2D simulation. In the lower inundation depth, the inundation area by combined 1D/2D simulation was larger than inundation area by 1D simulation. As the inundation depth increased, the inundation area by 1D simulation became wider. In the case of the 1D/2D combined simulation, low elevation areas along the river bank were inundated widely. Compared to 1D/2D combined simulation, the flood radius in some sections was longer in 1D simulation. In the 1D analysis, because the low altitude riverside farmlands are also assumed to stream, it is calculated that riverside farmlands have the same stage as the mainstream when the stream is overflowed. Therefore, the inundation area seems to be overestimated in those sections. In other regions, the inundation areas tend to be broken depending on overflow by each stream cross-section. In the case of river flooding, the overflow is expected to flow to the lower area depending on the terrain, such as the results of the combined 1D/2D simulation. It is concluded that the results of combined 1D/2D inundation simulation reflected the topographical characteristics of low-lying farmland.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2007년도 특별 심포지엄 논문집
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• pp.53-62
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• 2007

Preliminary gas hydrate surveys were carried out From 2000 to 2004 in the East Sea. Research results showed the geophysical evidence of gas hydrate existence. In 2005, Gas Hydrate R&D Organization was established and 10 year gas hydrate development program was initiated. In the $1^{st}$ stage of the program from 2005 to 2007, 6,600 L-km 2-D seismic survey was conducted in the $1^{st}$ year 2005, and $400\;km^2$ 3D survey was conducted in the $2^{nd}$ year 2006. Acquired seismic data were processed and seismic section and 3D cube were produced. By geophysical interpretation and velocity analysis, prospective areas were mapped and candidate drilling sites were recommended. For the precise interpretation, velocity was analyzed using AVO method, and BSR signal was analyzed using deconvolution method. For the prospective area, OBS and high-resolution seismic surveys were conducted. This presentation shows the introduction and examples of the research results of the geophysical methods applied for the gas hydrate exploration in the East Sea.

• 대기
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• 제22권3호
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• pp.345-356
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• 2012

The UK Met Office Unified Model at the KMA has been operationally utilized as the next generation numerical prediction system since 2010 after it was first introduced in May, 2008. Researches need to be carried out regarding various physical processes inside the model in order to improve the predictability of the newly introduced Unified Model. We first performed a preliminary experiment for the domain ($170{\times}170$, 10 km, 38 layers) smaller than that of the operating system using the version 7.4 of the UM local model to optimize its physical processes. The result showed that about 7~8% of the improvement ratio was found at each stage by integrating four factors (u, v, th, q), and the final improvement ratio was 25%. Verification was carried out for one month of August, 2008 by applying the optimized combination to the domain identical to the operating system, and the result showed that the precipitation verification score (ETS, equitable threat score) was improved by 9%, approximately.

• International Journal of Railway
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• 제4권3호
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• pp.70-73
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• 2011

Controlling the exterior and interior noise emission has become an important issue in the research and development of high speed trains. As the operating speed of the train increases, the noise emission characteristics are expected to deviate from that of the existing trains due to several changes in the basic train layout. For train speed in excess of 350 km/h in particular, the aerodynamic noise component starts to exceed the structure-borne noise component, and even an incremental speed increase is accompanied by a rapid elevation in the noise level. The present study presents an engineering approach for predicting the aerodynamic noise level at the design stage for high speed trains. The experimental noise measurements from test run of Korean high speed train under development are presented as a partial validation of the proposed approach. While the overall aerodynamic noise can be cast in a single power law relationship against the train speed, different parts of the train show power law relationships unique to each component.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1615-1617
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• 2009

The water resources project of 320 Ha second stage reclamation, in which including an University City, out of 800 Ha Ndata Farm, Malawa, had been under studied in this research. The challenge of C value of runoff coefficient was obtained as 0.8, by introducing the attenuation factors method, proposed by second author, an IDF dimensionless method customary used in Taiwan, proposed by the third author, is translated further to solve the project design rainfall; Rational Method, thus, obtains 11.5 CMS as the 5 year recurrence storage. The final job, completed by the third author's on-site performance, includs field alignments and discussions with the trustee, Malawa President H. E. Dr. Bingu Wa Mutharika, when a special concern of anti-theft. In order to provide sufficient supply up to an amount of 44,000 M3 during April to November, the sketch package includes 6 measurements: one water barrage, one sluice gate, one intake, one sediment reservoir, one water reservoir, and 3199 Km long gravity-driving hydraulic pipe.