• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 1999년도 봄 학술발표회 논문집
• /
• pp.137-144
• /
• 1999

The finite element method was adopted to find out the natural frequencies of a sinusoidally tapered beam with simply supported boundary conditions. The parameters considered in the numerical analysis are the taper parameter, $\alpha$ ($\alpha$=0.0, 0.1, ~ , 2.0) and the sectional property parameters, m and n [(m, n):(0, 2), (1, 3), (2, 4)]. It is generally known that the results of the numerical analysis corresponding to each pair of sectional property parameters, (m, n) are represented by second order polynominals of $\alpha$ . The coefficients of a in the polynominals are determined by using the regression technique, which reveals small m in most cases of given sectional property parameters (m, n).

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2006년도 추계학술대회 논문집
• /
• pp.555-556
• /
• 2006

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2001년도 봄 학술발표회 논문집
• /
• pp.34-41
• /
• 2001

Most of the eigenvalue analysis methods for the undamped or proportionally damped systems use the well-known Sturm sequence property to check the missed eigenvalues when only a set of the lowest modes is to be used for large structures. However, in the case of the non-proportionally damped systems such as the soil-structure interaction system, the structural control system and the composite structures, no counterpart of the Sturm sequence property for undamped systems has been developed yet. Hence, when some important modes are missed for those systems, it may leads to poor results in dynamic analysis. In this paper, a technique for calculating the number of eigenvalues inside the open disk of arbitrary radius for the eigenproblem with the damping matrix is proposed by applying Chen's algorithm and Gleyse's theorem. To verify the applicability of the proposed method, two numerical examples are considered.

• International Journal of Automotive Technology
• /
• 제7권1호
• /
• pp.101-107
• /
• 2006

The force and moment simulation of a steady-state rolling tire taking the effect of tread pattern into account is described using a steady-state transport method with ABAQUS. Tread meshes can not fully consider a tread pattern because detailed tread meshes are not allowed in the steady-state transport method. Therefore, the tread elements are modeled to have orthotropic property instead of isotropic property. The force and moment simulation has been carried out for the cases of both isotropic and orthotropic properties of tread elements. Both cases of simulation results are then compared with the experimental results. It is verified that the orthotropic case is in a better agreement with the experimental result than the isotropic case. Angle effects of tread pattern have been studied by changing the orientation angle of orthotropic property of tread. It is shown that the groove angle in the tread shoulder region has a more effect on force and moment of a tire than that in the tread center region.

• 대한산업공학회지
• /
• 제40권1호
• /
• pp.1-7
• /
• 2014

We consider a human contact social network that has connections through cellphone addresses. To construct such a social network, we use real call records provided by a large carrier, and connect to each other if there exists a call record between any two cellphone users. Due to its huge amount of data, we down-sample it in a way that the smallest-degree nodes are removed, in turn, from the network. For a moderate size of the networks we show that the degree distribution of the network follows a power-law distribution via linear regression analysis, implying the so-called scale-free property. We finally suggest some alternative measures to analyze a social network.

• EDISON SW 활용 경진대회 논문집
• /
• 제5회(2016년)
• /
• pp.228-233
• /
• 2016

Auxetic material is a material which has negative Poisson's ratio(NPR). Auxetic material shows some distinctive property like high energy absorbing property and high shear modulus. Among these, synclastic curvature is very interesting characteristic. When synclastic-curvature-material bends, it changes its shape like dome, contrary to non-auxetic material which changes its shape like saddle(anticlastic). This distinctive property could make it easy to manufacture curved structure like nose cone or wing panel in aerospace engineering. In this study, we studied a quantitative analysis about synclastic curvature of re-entrant panel with finite element model. We suggested a concept 'Degree of Synclasticity(DOS)', which means a ratio of curvature of load-direction and load-orthogonal direction. We studied the variation of DOS with two factor, unit cell inner angle(${\theta}$) and load position angle(${\phi}$). DOS decreases as ${\theta}$ increases because the unit cell goes out of auxetic-shape. As ${\phi}$ varies, DOS changes in a large range. So proper optimization of ${\phi}$ would be needed for application.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
• /
• pp.84-87
• /
• 1996

This paper presents a energy function to reflect the control effect of speed governor which has a cut-off property which means position and rate limit The proposed energy function satisfies the semi-negativeness of its time derivative and well reflects the parameters of speed governor to the energy function. The transient stability analysis by the direct method for the single machine infinite bus system has been conducted with the use of the proposed energy function, which shows that the results by the direct method well agree with that by the conventional time simulation method. This thesis shows a possibility of more accurate stability analysis by taking into account the cut-off property of speed governor's output.

• 한국정보전자통신기술학회논문지
• /
• 제10권1호
• /
• pp.117-124
• /
• 2017

본 논문에서는 미용기기 분야에 대한 특허 동향 분석을 통해 주요 경쟁자별 기술경쟁력 등의 분석을 실시하고, 지식재산권 중심의 기술 동향 분석 등을 바탕으로 과제기술의 특허 포트폴리오 및 특허 확보 전략을 도출하였다. 전략적인 IP(Intellectual Property) 기반 연구개발 계획 수립에 활용할 수 있도록 특허 포트폴리오를 분석하여 특허 장벽 및 공백분야를 제시함으로써, 연구개발의 방향을 설정하기 위한 기초정보로 활용하여 중복연구를 방지하고 연구개발과제 수행의 타당성에 대한 객관적인 특허정보를 제공하고자 한다.

• Communications for Statistical Applications and Methods
• /
• 제25권5호
• /
• pp.489-499
• /
• 2018

Jeonse is a unique property rental system in Korea in which a tenant pays a part of the price of a leased property as a fixed amount security deposit and gets back the entire deposit when the tenant moves out at the end of the tenancy. Jeonse deposit is very important in the Korean real estate market since it is directly related to the residential property sales price and it is a key indicator to predict future real estate market trend. Jeonse deposit data shows a skewed and heteroscedastic distribution and the commonly used mean regression model may be inappropriate for the analysis of Jeonse deposit data. In this paper, we apply a Bayesian quantile regression model to analyze Jeonse deposit data, which is non-parametric and does not require any distributional assumptions. Analysis results show that the quantile regression coefficients of most explanatory variables change dramatically for different quantiles. The regression coefficients of some variables have different signs for different quantiles, implying that even the same variable may affect the Jeonse deposit in the opposite direction depending on the amount of deposit.

• 한국연초학회지
• /
• 제29권2호
• /
• pp.80-84
• /
• 2007

This study was conducted to evaluate the prediction of sensory property of smoke from the leaf chemical property and characterize leaf chemical components for the best tobacco taste's leaves in burley tobacco. For analytical and sensory evaluations, sixteen grades were used. The major leaf chemical components to predict the sensory property of smoke were ether extract for tobacco-like, chloride for impact and total nitrogen/nicotine for irritation. Within ${\pm}20\;%$ range of difference, the predictable probabilities of sensory property of smoke from the leaf chemical properties were 100 % for tobacco-like, impact and irritation. As a result of K-means cluster analysis on the basis of tobacco taste, the desirable leaf chemical component contents were $6.5{\sim}6.8\;%$ in ether extract, $0.25{\sim}0.30\;%$ in chloride and $1.26{\sim}1.54$ in total nitrogen/nicotine ratio. This study suggest that the some regression equations may be useful to predict the sensory components of tobacco smoke from a few selected leaf chemical properties in burley tobacco and to select the burley tobacco leaves for enhance the tobacco taste of cigarette.