• 한국안전학회지
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• 제24권4호
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• pp.1-10
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• 2009

The characteristics of smoke emissions from diesel heavy duty vehicles which weigh over 5.5 tons was investigated by driving the vehicles with both the Lugdown 3 modes in the chassis dynamometer and tree accelerating mode under no load. The vehicles include commercial vehicles such as bus, microbus, trucks and specialized vehicles, etc. The total numbers of the vehicles tested were 200. The light extinction method was used to measure the smoke emissions from the vehicles tail pipe. The values of the smoke emissions in the tree accelerating mode showed $0{\sim}20%$ band nearly independent of both the mileage and year of production of the tested vehicles, while those in the Lugdown 3 modes showed $0{\sim}99%$ of wide band. The correlation coefficients between the values of the smoke emissions with both the Lugdown 3 modes and the free acceleration mode were 0.12, 0.08, 0.12, respectively. The inspection with Lugdown 3 modes is better one than that with tree acceleration from the point of exact inspection of the diesel vehicles' smoke emission.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.334-335
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• 2006

Solid insulation exposed to voltage is degraded by electrical tree process. And the degradation of the insulation is accelerated by voltage application. For this experimental, specimen of electrical tree model is made by XLPE (cross-linked polyethylene). And the size of the specimen is 7*5*7 $mm^3$. Distance of needle and plane is 2 mm. Voltages applied for acceleration test are 12 kV to 15 kV. And distribution characteristic of degraded stage is studied too. As a PD detecting and data process, discharge data acquire from PD detecting system (Biddle instrument). The system presents statistical distribution as phase resolved. Moreover the processing time of electrical tree is recorded to know the speed of degradation according to voltage.

• 한국군사과학기술학회지
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• 제21권6호
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• pp.894-903
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• 2018

In the case of helicopters, the development of parts technology is rapidly changing, and the complexity is rapidly increasing. Particularly, the surge of various electric and electronic systems is recognized as a problem that is directly related to the safety of the helicopter. Due to these problems, there is a growing interest in reliability evaluation in the face of the problem of confirming and certifying the reliability of parts in the development stage. In this paper, the analysis of the failure mechanism of the wiper system was carried out, and the priority and importance of each failure mode were checked by using the results, and major stress factors were derived and the corresponding acceleration model was selected. Also, the accelerated lifetime test time was calculated according to the life test time, acceleration status and acceleration level of the steady state by using the selected acceleration model and characteristic values.

• Steel and Composite Structures
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• 제44권1호
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• pp.49-63
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• 2022

This study aims to develop ensemble machine learning (ML) models for estimating the peak floor acceleration and maximum top drift of steel moment frames. For this purpose, random forest, adaptive boosting, gradient boosting regression tree (GBRT), and extreme gradient boosting (XGBoost) models were considered. A total of 621 steel moment frames were analyzed under 240 ground motions using OpenSees software to generate the dataset for ML models. From the results, the GBRT and XGBoost models exhibited the highest performance for predicting peak floor acceleration and maximum top drift, respectively. The significance of each input variable on the prediction was examined using the best-performing models and Shapley additive explanations approach (SHAP). It turned out that the peak ground acceleration had the most significant impact on the peak floor acceleration prediction. Meanwhile, the spectral accelerations at 1 and 2 s had the most considerable influence on the maximum top drift prediction. Finally, a graphical user interface module was created that places a pioneering step for the application of ML to estimate the seismic demands of building structures in practical design.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.464-465
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• 2007

Solid insulation exposed to voltage is degraded by electrical tree process. And the degradation of the insulation is accelerated by voltage application. For this experimental, specimen of electrical tree model is made by XLPE (cross-linked polyethylene). And the size of the specimen is $7*5*7\;mm^3$. Distance of needle and plane is 2 mm. Voltages applied for acceleration test are 12 kV to 15 kV. And distribution characteristic of degraded stage is studied too. As a PD detecting and data process, discharge data acquire from PD detecting system (Biddle instrument). The system presents statistical distribution as phase resolved. Moreover the processing time of electrical tree is recorded to know the speed of degradation according to voltage.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2011년도 한국컴퓨터종합학술대회논문집 Vol.38 No.1(C)
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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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.215-216
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• 2006

Solid insulation exposed to voltage is degraded by electrical tree process. And the degradation of the insulation is accelerated by voltage application. For this experimental, specimen of e1ectrical tree model is made by XLPE (cross-linked polyethylene). And the size of the specimen is $7*5*7\;mm^3$. Distance of need1e and plane is 2 mm. Voltages applied for acceleration test are 12 kV to 15 kV. And distribution characteristic of degraded stage is studied too. As a PD detecting and data process, discharge data acquire from PD detecting system (Biddle instrument). The system presents statistical distribution as phase resolved. Moreover the processing time of electrical tree is recorded to know the speed of degradation according to voltage.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.467-467
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• 2007

Solid insulation exposed to voltage is degraded by electrical tree process. And the degradation of the insulation is accelerated by voltage application. For this experimental, specimen of electrical tree model is made by XLPE (cross-linked polyethylene). And the size of the specimen is $7^*5^*7mm^3$. Distance between needle and plane is 2 mm. Voltages applied to acceleration test are ranged 12 to 15 kV. And distribution characteristic of degraded stage is studied too. By PD detecting and data processing, discharge data was acquired from PD detecting system (Biddle instrument). The system presents statistical distribution of phase resolved. Moreover, the processing time of electrical tree is recorded to know the speed of degradation according to voltage. Finally, it's used PD classification by ANFIS method.

• 한국지구과학회지
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• 제37권1호
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• pp.52-61
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• 2016

본 연구의 목적은 한반도의 고유한 지진-지체구조 특성이 반영된 입력자료를 사용하여 한반도의 확률론적 지진위험지도를 제작하는 것이다. 지진입력자료들은 다수의 전문가에 의해 제공받았으며, 최대지반가속도(Peak Ground Acceleration: PGA)에 대한 지진위험도값은 USGS 지진재해도 프로그램(Harmsen, 2008)을 일부 수정하여 산출하였다. 전문가들로부터 제공된 지진입력자료들의 불확실성은 논리수목 방법을 적용하여 최종 지진재해도 계산에 반영하였다. PGA 분포 패턴은 각 전문가들이 제시한 면적지진원도 형상에 매우 민감하며, 그 형상과 유사한 모양을 보여준다. 지진위험지도는 5, 10, 20, 50, 100, 250, 500년 동안 초과확률 10%에 해당하는 최대지반가속도를 등치선 형태로 나타내었다. 모든 재현주기에서 황해도 일대를 제외한 북한지역이 남한지역보다 현저하게 낮은(약 50%) PGA 기댓값을 나타낸다. 전체적으로 남한의 동남부 일대와 북한의 황해도 일대가 약간 높은 값을 보이면서 북서-남동 방향으로 등치도 값의 분포가 신장되어 나타남을 보인다. 또한, 강원도 북부 일대가 타 지역에 비해 약간 낮아지는 경향을 보인다. 본 연구결과는 국내 주요 구조물의 내진성능 향상을 위한 기초자료로서 유용하게 활용될 수 있을 것으로 사료된다.

• 한국멀티미디어학회논문지
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• 제17권1호
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• pp.69-76
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• 2014

대용량 지형 데이터는 최신 그래픽 하드웨어를 사용해도 실시간으로 표현하기가 어렵다. 일반적으로 이런 대용량 지형 데이터를 실시간에 처리하기 위해 연속 상세 단계 기법 같은 메쉬 간략화 기법이 사용된다. 하지만 기하 분할(geometry splitting)과 같이 기존의 GPU기반 사진트리를 사용하는 기법은 트리의 깊이가 깊어질수록 많은 정점을 사용하고 이를 다시 재전송하기 때문에 성능이 저하되며 텍스처를 이용해 트리를 구성하기 때문에 트리의 용량이 커지는 단점이 있다. 이런 단점을 해결하기 위해 본 논문에서는 사진트리 기반의 묶음(chunk)으로 구성된 상세 단계 선별 기법을 GPU에서 처리하는 실시간 지형 렌더링 기법을 제안한다. 제안하는 방법은 기하 분할 기법의 단점을 해결하기 위해 트리 탐색을 제한하고 테셀레이터(tessellator)에서 묶음을 생성한 후 렌더링함으로써 트리 탐색을 줄이고 묶음을 GPU에서 바로 생성할 수 있어 효율적으로 지형을 렌더링할 수 있다.