현재 국내외적으로 다양한 강재 댐퍼의 형상에 대한 연구가 이뤄지고 있다. 강재 댐퍼는 제진장치 중 하나로 항복을 통해 지진에너지를 흡수 및 소산하여 본 구조물을 보호한다. 최근 적용되고 있는 면내 전단 변형에 의해 작동하는 댐퍼는 응력이 특정 부위에 집중되어 재료의 대부분이 본래의 역량을 발휘하지 못하는 한계가 있었다. 따라서, 본 연구에서는 이 한계를 극 복하고자 전역 최적화 기법 중 하나인 뻐꾸기 탐색을 적용해 최적 형상을 설계하였다. 탐색된 최적 형상을 토대로 수치해석과 실제 실험을 통한 성능검증을 수행했다. 최적 형상으로 설계된 댐퍼는 안정적인 이력거동을 보이고, 높은 에너지 소산능력을 확 보하는 것으로 나타났다. 본 연구에서는 전역 최적화 기법을 적용한 최적 설계 방법을 제시하고 그 결과를 검증함으로써, 다양한 형태의 공학적 문제 해결에 대한 적용 가능성을 제시하였다.

The multi-layered heat source model is a model that can cover most of existing studies and can be defined with a simple formula. Based on the methodology performed in previous studies, the welding heat source was found through experiments and FEM under the welding power conditions of three cases and the parameters of the welding heat source were analyzed according to the welding power. In this study, parameters of fiber laser welding heat source according to welding power were searched through optimization algorithm and finite element analysis, and the correlation was analyzed. It was confirmed that the concentration of the welding heat source in the 1st layer was high regardless of the welding power, and it was confirmed that the concentration of the welding heat source in the 5th layer (last layer) increased as the welding power increased. This reflects the shape of the weld bead that appears during actual fiber laser welding, and it was confirmed that this study represents the actual phenomenon.

In this study, a welding heat source model was presented and verified during fiber laser welding. The multi-layered heat source model is a model that can cover most of existing studies and can be defined with a simple formula. It consists of a total of 12 parameters, and an optimization algorithm was used to find them. As optimization algorithms, adaptive simulated annealing, multi island genetic algorithm, and Hooke-Jeeves technique were applied for comparative analysis. The parameters were found by comparing the temperature distribution when the STS304L was bead on plate welding and the temperature distribution derived through finite element analysis, and all three models were able to derive a model with similar trends. However, there was a deviation between parameters, which was attributed to the many variables. It is expected that a more clear welding heat source model can be derived in subsequent studies by giving a guide to the relational expression and range between variables and increasing the temperature measurement point, which is the target value.

Welding is the most widely used technology for manufacturing in the automobile, and shipbuilding industries. Fiber laser welding is rapidly introduced into the field to minimize welding distortion and fast welding speed. Although it is advantageous to use finite element analysis to predict welding distortion and find optimized welding conditions, there are various heat source model for fiber laser welding. In this study, a welding heat source was proposed using a multi-layered heat source model that encompasses most of the existing various welding heat source models: conical shape, curved model, exponential model, conical-cylindrical model, and conical-conical model. A case study was performed through finite element analysis using the radius of each layer and the ratio of heat energy of the layer as variables, and the variables were found by comparing them with the actual experimental results. For case study, by applying Adaptive simulated annealing, one of the global optimization algorithms, we were able to find the heat source model more efficiently.

The estimation of heat source model is very important for heat transfer analysis with finite element method. Part I of this study used adaptive simulated annealing which is one of the global optimization algorithm for anticipating the parameters of the Goldak model. Although the analysis with 3D model which depicted the real situation produced the correct answer, that took too much time with moving heat source model based on Fortran and Abaqus. This research suggests the procedure which can reduce time with maintaining quality of analysis. The lead time with 2D model is reduced by 90% comparing that of 3D model, the temperature distribution is similar to each other. That is based on the saturation of heat transfer among the direction of heat source movement. Adaptive simulated annealing with 2D model can be used to estimate more proper heat source model and which could enhance to reduce the resources and time for experiments.

Anticipation of welding deformation with finite element method is a very interested topic in the industries, adequate heat source model is essential for concluding reasonable results. This study is related to estimate the parameters of Goldak heat source model, and global optimization algorithm is applied to this research. The heat affected zone (HAZ) boundary line of bead on plate (BOP) welding is used as the target, parameters of heat sources are used as the variables. Adaptive simulated annealing is applied and the optimal result is obtained out of 1,000 candidates. The convergence of finite element method and the global optimization is meaningful for estimation of welding deformation, which could enhance to reduce the resources and time for experiments.

Introduction In the contemporary business environment, fashion companies ought to cope with fundamental changes marketing communication has conventionally been performed. In response to shifting socio-demographic, environmental and market-related conditions, gradually new forms of fashion promotion have evolved (Fill, 2006). Nowadays, the global fashion industry experiences a reduced dependence on mass media advertising and an enlarged reliance on dialogic, relationship-oriented and digitally grounded communication methods (Chitty, Barker, Valos & Shimp, 2012). Against this backdrop, it is irrefutable that social media technologies have been remarkably transforming the ways in which modern-day fashion communication is practiced (Brennan & Schafer, 2010; Funk et al., 2016; Dillon, 2012; Saarinen, Tinnilä & Tseng, 2006). The competitive and widely saturated apparel market is facing an era of intensive proliferation of brands, an epoche of awe bombardment of advertisements, which makes a well-though-out communicational strategy ever more imperative, particularly in a cross-cultural context (Dillon, 2012). Yet, studies that analyze the importance of social media in relation to traditional means of fashion communication are scarce. Even though, empirical introductions start being made to this explicit issue, considerable research deficiency subsists in the realm of cross-cultural fashion communication and social media optimization. Therefore, the rationale of this paper at hand is to contribute to balance out this research gap by providing evidence from four countries.

This paper is concerned with finding the global optimal solutions for the redundancy optimization problems in series-parallel systems related with system safety. This study transforms the difficult problem, which is classified as a nonlinear integer problem, into a 0/1 IP(Integer Programming) by using binary integer variables. And the global optimal solution to this problem can be easily obtained by applying GAMS (General Algebraic Modeling System) to the transformed 0/1 IP. From computational results, we notice that GA(Genetic Algorithm) to this problem, which is, to our knowledge, known as a best algorithm, is poor in many cases.

본 연구에서는 전체탐색기법 중 Simplex법의 원리를 이용한 SCE-UA법과 Annealing-Simplex (A-S)법을 일유출량 추정 수문모형인 탱크모형의 매개변수 보정에 적용하여 국부탐색기법인 Downhill Simplex법의 결과와 비교하여 탐색능력을 평가하였다. 오차가 없는 합성자료를 사용한 보정에서 A-S법이 목적함수에 관계없이 전역최적해를 탐색하는 결과를 나타냈으며, SCE-UA법은 ABSERR를 목적함수로 사용할 경우에 전역최적해를 탐색