• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.188.1-188.1
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• 2010

This paper describes the effort for the development of an actual wind simulation method on the wind turbine performance evaluation. It should be emphasized that the deep knowledge on real wind field is a key factor for both the design of a wind turbine and the performance evaluation. With this reason, there had been several simulation attempts to accurately match with the actual wind data. With an existing wind generation algorithm is under consideration, this study introduces several more new concepts including Van der Hoven spectrum being implemented in different methodology. Also this paper will compare the result from the wind simulations by using the basic formula with that by using MATLAB and SIMULINK previously developed. In addition, like the existing wind generation algorithm, random process for actual wind field simulation and white noise are incorporated to closely produce the actual wind field models.

• Interaction and multiscale mechanics
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• 제1권4호
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• pp.423-435
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• 2008

This paper employs the reproducing kernel (RK) approximation for evaluation of field theory-based incompatibility tensor in a polycrystalline plasticity simulation. The modulation patterns, which is interpreted as mimicking geometrical-type dislocation substructures, are obtained based on the proposed method. Comparisons are made using FEM and RK based approximation methods among different support sizes and other evaluation conditions of the strain gradients. It is demonstrated that the evolution of the modulation patterns needs to be accurately calculated at each time step to yield a correct physical interpretation. The effect of the higher order strain derivative processing zone on the predicted modulation patterns is also discussed.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2004년도 춘계 학술발표대회 개요집
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• pp.327-329
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• 2004

Reliability evaluation of the welded structure for industrial structures/facilities such as power plant and petro-chemical refinery facilities is very important, and especially the reliability diagnosis of the structure is based on the exact evaluation of materials properties. But, the conventional Pre-Qualification test had the difficulty of evaluating the real material properties in the field because the test was made on the specimen with the simulated welding for the in-field welding condition. Therefore, a continuous indentation technique was proposed for simple and non-destructive testing of in-field structures and for selective testing of local range such as heat affected zone and weldment.

• 한국터널지하공간학회 논문집
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• 제6권2호
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• pp.151-160
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• 2004

본 연구는 국내 재래식 철도 터널에서 발생한 아치부 종방향 균열 부위에 대하여 각종 현장조사를 실시하여 터널의 변상상태를 파악한 것이다. 현장 외관조사 및 각종 비파괴 조사를 통하여 균열 부위에 대한 상세한 조사를 실시하였으며 현장조사 결과를 토대로 균열의 발생 원인을 추정하였다. 아울러 현장여건을 고려한 안전성 해석을 실시하여 터널 구조물의 균열 발생 가능성을 검토하였다.

• 한국초전도ㆍ저온공학회논문지
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• 제13권4호
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• pp.14-17
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• 2011

The evaluation of the electromechanical properties of HTS CC tapes is one of the foremost procedures to be done to ensure the applicability of superconducting wires to electric devices. A precise measurement of the stress and strain is important in deriving the mechanical properties under operating environment. Up to now, there is no standard test method yet for the electromechanical property evaluation of HTS tapes under self field and external magnetic field although there are already reports on the different devices used to evaluate these properties. Strain can be measured by adopting a strain gauge or a high resolution double extensometer. In this study, strain effect on $I_c$ in HTS CC tapes under magnetic fields was evaluated. Comparison of advantages and setback of strain measuring devices were discussed. In addition, a dual strain measurement system using both the SG and extensometer may be practical to lessen the burden in case one of the measuring devices does not work well.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.451-456
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• 2004

In this study, evaluation was carried out for reduction method of floor impact noise through field test and the effective methods for heavy impact noise were proposed. As a field test, impact noise reduction materials such as EPP, EEPS, EVA, PE and so on, did not satisfied the recommandation value at the condition of 150mm thickness concrete slab. The evaluation results for those materials by 'inverse A curve' showed $53\sim55dB$ at heavy impact noise and $53\sim58dB$ at light impact noise. But, two methods proposed by authors were evaluated $47\sim50dB$ at heavy Impact noise and $54\sim58dB$ at light Impact noise on the similar concrete slab thickness.

• Smart Structures and Systems
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• 제32권2호
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• pp.111-121
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• 2023

This study proposes an automated assembly performance evaluation method for prefabricated steel structures (PSSs) using machine learning methods. Assembly component images were segmented using a modified version of the receptive field pyramid. By factorizing channel modulation and the receptive field exploration layers of the convolution pyramid, highly accurate segmentation results were obtained. After completing segmentation, the positions of the bolt holes were calculated using various image processing techniques, such as fuzzy-based edge detection, Hough's line detection, and image perspective transformation. By calculating the distance ratio between bolt holes, the assembly performance of the PSS was estimated using the k-nearest neighbors (kNN) algorithm. The effectiveness of the proposed framework was validated using a 3D PSS printing model and a field test. The results indicated that this approach could recognize assembly components with an intersection over union (IoU) of 95% and evaluate assembly performance with an error of less than 5%.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.509-522
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• 2010

There is a increasing trend in disaster occurrence due to steep-slope failures in urban area during typhoon and torrential rain season in Korea. The underlying hazards that cause slope failure are mainly linked with urbanization and industrialization. To minimize the disaster damages by slope failure, objective and unified evaluation approached are desired. Since currently available evaluation checklists are developed for specific purposed, there is a limitation to adapt those checklists for stability evaluation in natural terrain. This study proposes an improved evaluation checklist based on the comparison of previous checklists and applicability and feasibility are analyzed implementing field application.

• 지질공학
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• 제19권1호
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• pp.99-108
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• 2009

기존의 급경사지재해 평가방법은 현장조사를 기반으로 하여 일정 과정의 실내분석이 실시된 후 그 결과를 도출하기 때문에, 현장에서 즉각적인 평가결과를 도출하기 어려운 점이 있었다. 이러한 문제점과 기존의 주관적 평가방법에서 발생하는 평가결과의 오차를 줄이기 위해 본 연구에서는 현장에서 직접 관련요소를 조사하고 이를 토대로 급경사지재해 취약성을 객관적으로 평가할 수 있는 방법을 개발하고자 노력하였다. 이를 위해 응용통계기법의 하나인 AHP 분석을 이용하여 급경사지재해 취약성 평가표를 개발하였는데, 이는 전문가 설문을 통한 AHP분석 방법의 결과를 이용해 수행한 것으로서, 각 평가항목과 평가항목별 세부등급에 대한 가중치를 각각 설정하였다. 평가항목들의 가중치를 100점으로 환산하여 점수화 한 결과 사면경사가 가장 높은 중요도를 보이고, 투수계수, 함수비, 공극율, 암질, 그리고 고도의 순서로 결정되었다. 이렇게 결정된 평가항목별 점수를 기준으로 평가항목 각각의 세부등급에 대한 점수를 할당하여 급경사지재해 취약성 평가표를 개발하였다. 급경사지재해 취약성 평가표를 이용하여 평가자는 평가대상 지점에 대해 각 평가항목별 해당 속성, 즉 세부등급을 선택하고, 선택된 각 속성별 평가점수를 더하면 급경사지재해 취약성을 점수로 파악할 수 있다.

• Structural Engineering and Mechanics
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• 제31권5호
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• pp.507-526
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• 2009

Based on numerical and experimental methods, a systematic structural evaluation of a steel natatorium in service was carried out in detail in this paper. Planning of inspection tasks was proposed firstly according to some national codes in China in order to obtain the economic and reliable results. The field visual inspections and static computation were conducted in turn under in-service environmental conditions. Further a three-dimensional finite element model was developed according to its factual geometry properties obtained from the field inspection. An analytical modal analysis was performed to provide the analytical modal properties. The field vibration tests on the natatorium were conducted and then two different system identification methods were used to obtain the dynamic characteristics of the natatorium. A good correlation was achieved in results obtained from the two system identification methods and the finite element method (FEM). The numerical and experimental results demonstrated that the main structure of the natatorium in its present status is safe and it still satisfies the demand of the national codes in China. But the roof system such as purlines and skeletons must be removed and rebuilt completely. Moreover the system identification results showed that field vibration test is sufficient to identify the reliable dynamic properties of the natatorium. The constructive suggestion on structural evaluation of the natatorium is that periodic assessment work must be maintained to ensure the natatorium's safety in the future.