• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1494-1498
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• 2007

Impulsive shooting noise is basically complex phenomenon which contains the linear and non-linear characteristics. For those reasons, numerical analysis of impulsive shooting noise has the difficulties in control of the numerical stability and accuracy on the simulation. In this research, Wave-number Extended Finite Volume Scheme (WEFVS) is applied to the numerical analysis of impulsive shooting noise. In the muzzle blast flow simulation, the generation of the precursor wave and the induced vortex ring are observed. Consequently, blast wave. vortex ring interaction and vortex ring. bow shock wave interaction are evaluated on the shooting process using the accurate and stable scheme. The sound generation in the interactions can be explained by the vorticity transport theorem. The shear layer is evolved behind the projectiles due to the jet flow. In these computations, the impulsive shooting noise is generated by the complex interaction with shooting process and is propagated to the far-field boundary. The impulsive shooting noise generation can be observed by the applications of WEFVS and analyzed by the physical phenomena.

• 한국전자통신학회논문지
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• 제6권3호
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• pp.417-423
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• 2011

일반적으로 기존 연구와의 중복성을 피하고 독창적인 연구를 진행하기 위해서는 연구자들은 사전에 특허정보를 분석하여야 한다. 본 논문에서는 풍력 발전에 대한 현재의 동향을 이용한 등급 기준 개발을 주요국의 기술 위치, 국가별 피인용비와 시장력 확보지수, 특허 포트폴리오 분석, 특허 출원인 국적 분석을 통하여 수행하였다. 이러한 특허 정보 분석은 앞으로 풍력발전의 연구 개발의 방향을 결정하는데 활용할 수 있을 것으로 기대한다.

• Current Photovoltaic Research
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• 제7권2호
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• pp.38-45
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• 2019

In this paper, we analyzed the present status of the safety manager and safety assurance aspects through a complex analysis on the operational aspects, marketability and electrical safety aspects of photovoltaic power generation facilities. In the analysis of the equipment status, we analyzed the status and operated status of the installed PV system in Korea and the correlation between the safety manager and the accident. In addition, we analyzed the direction of the ESS through the analysis of the installation status of the ESS, and applied it to the interpretation part of the ESS associated with the solar power generation. The status of the electric safety manager can be used to analyze the data for selecting the electric safety manager by capacity by analyzing the accident status, the electric safety manager operation status, the safety management time by capacity, and the electric safety manager market.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2005년도 춘계학술대회 학술발표 논문집 제15권 제1호
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• pp.139-142
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• 2005

This paper describes an automatic finite element (FE) mesh generation for three-dimensional structures consisting of free-form surfaces. This mesh generation process consists of three subprocesses: (a) definition of geometric model, i.e. analysis model, (b) generation of nodes, and (c) generation of elements. One of commercial sol id modelers is employed for three-dimensional sol id structures. Node is generated if its distance from existing node points is similar to the node spacing function at the point. The node spacing function is well control led by the fuzzy knowledge processing. The Delaunay method is introduced as a basic tool for element generation. Automatic generation of FE meshes for three-dimensional sol id structures holds great benefits for analyses. Practical performances of the present system are demonstrated through several mesh generations for three-dimensional complex geometry.

• 한국멀티미디어학회논문지
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• 제25권11호
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• pp.1572-1581
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• 2022

Energy conversion to renewable energy is being promoted to solve the recently serious environmental pollution problem. Solar energy is one of the promising natural renewable energy sources. Compared to other energy sources, it is receiving great attention because it has less ecological impact and is sustainable. It is important to predict power generation at a future time in order to maximize the output of solar energy and ensure the stability and variability of power. In this paper, solar power generation data and sensor data were used. Using the PCC(Pearson Correlation Coefficient) analysis method, factors with a large correlation with power generation were derived and applied to the GAM(Generalized Additive Model). And the prediction accuracy of the power generation prediction model was judged. It aims to derive efficient solar power generation in the future and improve power generation performance.

• International Journal of Korean Welding Society
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• 제1권1호
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• pp.71-77
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• 2001

The characteristics of the fume generation in a flux cored arc welding were investigated using the fume collection chamber developed. The Korean Standard concerning the method for the evaluation of the fume generation rate(FGR) was updated by the evaluation method obtained through this study. It was found that the effect of humidity in the test environment should be considered and the automatic welding method had to be employed for the purpose of the exact evaluation of the fume generation rate. The results showed that the fume generation rate was influenced by the welding parameters. The important factors were the welding current arc voltage, travel speed, and contact tip to work distance(CTWD) that affected the heat input as well as the torch angle and the shielding gas flow rate that influenced the shielding effect. The fume generation rate increased as the heat input increased and the shielding effect decreased. It was also observed that the effect of the welding current is much grater than the other welding parameters.

• 대한기계학회논문집A
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• 제28권6호
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• pp.717-725
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• 2004

A power generation systems are proposed to convert ambient mechanical vibration into electrical energy using cantilever-type piezoelectric materials. The vibration-based power device can be used for self-powered systems without batteries. This paper presents the theoretical analysis for the coupled equations of piezoelectric and structural motions and investigates the dynamic characteristics of the self-power system using transfer function method. The theoretical model is verified by the finite element analysis of the resonance frequency, the dynamic response of the structure and the sensor sensibility. Experimental results measured using a prototype system agree with the theoretical predictions. The system is shown to produce 34.5 ㎼ in average. Finally, we perform the optimal design for system variables to maximize output power.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제6권2호
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• pp.144-149
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• 2006

This paper describes a novel automated analysis system for bellows of piping system. An automatic finite element (FE) mesh generation technique, which is based on the fuzzy theory and computational geometry technique, is incorporated into the system, together with one of commercial FE analysis codes and one of commercial solid modelers. In this system, a geometric model, i.e. an analysis model, is first defined using a commercial solid modelers for 3-D shell structures. Node is generated if its distance from existing node points is similar to the node spacing function at the point. The node spacing function is well controlled by the fuzzy knowledge processing. The Delaunay triangulation technique is introduced as a basic tool for element generation. The triangular elements are converted to quadrilateral elements. Practical performances of the present system are demonstrated through several analysis for bellows of piping system.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제6권1호
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• pp.58-63
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• 2006

This paper describes a novel automated analysis system for bellows of piping system. An automatic finite element (FE) mesh generation technique, which is based on the fuzzy theory and computational geometry technique, is incorporated into the system, together with one of commercial FE analysis codes and one of commercial solid modelers. In this system, a geometric model, i.e. an analysis model, is first defined using a commercial solid modelers for 3-D shell structures. Node is generated if its distance from existing node points is similar to the node spacing function at the point. The node spacing function is well controlled by the fuzzy knowledge processing. The Delaunay triangulation technique is introduced as a basic tool for element generation. The triangular elements are converted to quadrilateral elements. Practical performances of the present system are demonstrated through several analysis for bellows of piping system.

• 한국유체기계학회 논문집
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• 제14권3호
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• pp.18-22
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• 2011

This paper presents the transient performance analysis of a micro-hydro Pelton turbine for the osmotic power generation using the commercially available computational fluid dynamics (CFD) code, ANSYS CFX. The detailed flow field in the micro Pelton turbine with a single-jet is investigated by the CFD code adopted in the present study. Predicted characteristic curves agree fairly well with measured data for a prototype Pelton turbine over the normal operating conditions. The computational analysis method presented herein can be effectively applied to the hydraulic design optimization process of general purpose Pelton turbine runners.