• Structural Engineering and Mechanics
• /
• v.41 no.2
• /
• pp.263-284
• /
• 2012

This paper aims to propose a computational technique for estimating the region of attraction (RoA) for autonomous nonlinear systems. To achieve this, the collocation method is applied to approximate the Lyapunov function by satisfying the modified Zubov's partial differential equation around asymptotically stable equilibrium points. This method is formulated for n-scalar differential equations with two classes of basis functions. In order to show the efficiency of the suggested approach, some numerical examples are solved. Moreover, the estimated regions of attraction are compared with two similar methods. In most cases, the proposed scheme can estimate the region of attraction more efficient than the other techniques.

• Journal of Korean Port Research
• /
• v.14 no.3
• /
• pp.279-290
• /
• 2000

The purpose of this study is to suggest the analytical framework for a spatial structure of a tourism destination master plan by the two types of the tourism development models: Tourist attraction System Model and Tourism Destination Region Design Model. The resort development plan is introduced as a planning tool for regenerating the eastern Pusan regions, but the economic and environmental impacts and the sociocultural dilemma accompanied by the development should be fully considered before launching the business. The development plan announced currently is traced and examined in comparison with the upper-leveled and related plans. The Tourist Attraction System Model based on the systems theory is applied to the designated regions. The Tourism Destination Region Design Model then is applied for analyzing the components of each region on the master plan. The results of the findings suggest that the tourism destination plan is basically different from a general master plan on the physical comprehensive plan, the destination is recognized as a subsystem of the whole tourism system, and thus tourism destination plan is considered as a spatial arrangement of tourism facilities and the inter- and intra-circulation.

• Journal of Korean Society on Water Environment
• /
• v.31 no.1
• /
• pp.1-11
• /
• 2015

In this study, the attraction efficiency of the by-pass fishway installed at Dalseong Weir in Nakdong River was assessed according to operation of the attraction waterway by using River2D which is a two-dimensional physical habitat simulation model. The model was calibrated and validated through the measured water elevation. The attraction efficiency of the fishway was evaluated at the low flow condition because the target fish, Zacco platypus (Z. platypus), have moved frequently up and downstream at the spawning season from April to June. From simulation results, it can be deduced that the attraction efficiency at situation of open attraction waterway is superior to that of close attraction waterway. Also it is shown that velocity field at inner region of the fishway is suitable for migration of the fish.

• Bulletin of the Korean Mathematical Society
• /
• v.46 no.6
• /
• pp.1237-1248
• /
• 2009

The domain of attraction of a nonlinear differential equations is the region of initial points of solution tending to the equilibrium points of the systems as the time going. Determining the domain of attraction is one of the most important problems to investigate nonlinear dynamical systems. In this article, we first present two algorithms to determine the domain of attraction by using the moment matrices. In addition, as an application we consider a class of SIRS infection model and discuss asymptotical stability by Lyapunov method, and also estimate the domain of attraction by using the algorithms.

• Korean Journal of Mathematics
• /
• v.9 no.1
• /
• pp.67-73
• /
• 2001

For some equation related with exponential function, we seek roots and find the properties of the roots. By using the relation of the roots and attractors, we find a region in the basin of attraction of the attractor at infinity for Newton's method for solving given equation.

• Journal of the Economic Geographical Society of Korea
• /
• v.13 no.4
• /
• pp.710-726
• /
• 2010

The main aim of this paper is to explore a strategy for the attraction of POSCO into Gangwon province through the collaborative network of industry-University institute-government. Although Gangwon province has abundant resources, the industrial development is stagnant owing to unfavorable conditions of industrial location. However, while attracting an magnesium smelting factory of POSCO into Gangneung city, the industrial development in the province faces a new phase for the industrialization in the region. Successful factors of the attraction are as follows; firstly, mutual collaborations of local government, research institutes, region-based firms; secondly, trust throughout rational proposals which are focused upon mutual regard of local government, POSCO and research institutes; thirdly, stategies for the attraction of POSCO which are based upon thorough analysis on such firm; finally, securing the demand market of forward industries.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.24 no.1 s.173
• /
• pp.240-249
• /
• 2000

An improved global optimization algorithm is developed by extending the domain elimination method. The concept of triangular patch consists of two or more trajectories of local minimizations is introduced to widen the attraction region of the domain elimination method. Using the an-]c between each of three vertices of the patch and a design point, we measure the proximity, between the design point and the patch. With the Gram-Schimidt orthonormalization, this method can be extended to general n-dimensional problems. We code the original domain elimination algorithm and a patch-based algorithm. Then we compare the performance of two algorithms. Through the well-known example problems. the algorithm using patch is shown to be superior to the original domain elimination algorithm in view of computational efficiency.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.30 no.10 s.253
• /
• pp.1202-1208
• /
• 2006

This paper presents an experimental characteristics of electro-hydraulic proportional pressure control valve. In this study, poppet and valve body which are assembled into the proportional solenoid were designed and manufactured. The constant force characteristics of proportional solenoid actuator in the control region should be independent of the plunger position in order to be used to control the valve position in the fluid flow control system. The stroke-force characteristics of the proportional solenoid actuator is determined by the shape (or parameters) of the control cone. In this paper, steady state and transient characteristics of the solenoid actuator for electro-hydraulic proportional valve are analyzed using finite element method and it is confirmed that the proportional solenoid actuator has a constant attraction force in the control region independently on the stroke position. The effects of the parameters such as control cone length, thickness and taper length are also discussed.

• Journal of Electrical Engineering and information Science
• /
• v.3 no.3
• /
• pp.322-329
• /
• 1998

Stability analysis of nonlinear systems is mostly based on the Lyapunov stability theory. The well-known Lyapunov function method provides precise and rigorous theoretical backgrounds. However, the conventional approach to direct stability analysis has been performed without taking account of damping effects, which is pointed as a minor but crucial drawback. For accurate has been performed without taking account of damping effects, which is pointed as a minor but crucial drawback. For accurate stability analysis of nonlinear systems, it is required to take the damping effects into account. This paper presents a new method to derive a group of Lyapunov functions to reflect the damping effects by considering the integral relationships of the system governing equations. A systematical approach is developed to convert a part of damping loss into some appropriate system energy terms. Examples show that the proposed method remarkably improves the estimation of the region of attraction compared considering damping effects. The proposed method can be utilized as a useful tol to determine the region of attraction.

• Journal of Digital Convergence
• /
• v.8 no.3
• /
• pp.63-77
• /
• 2010

The purpose of this study is to determine potential effects of region marketing activities on attraction of domestic or overseas business. In order to meet the goal, this study set a research model and hypotheses on the basis of preceding reference literatures and case studies. This study identifies management environment, life environment, marketability, investment supporting environment as the variables of investment decision and urban attitude. As a result, it was found that marketability and investment supporting environment had positive effects on urban attitudes and investment decision, and urban attitudes had positive effects on investment decision as well.