• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.55 no.1
• /
• pp.1-6
• /
• 2006

The emergence of competitive power market makes dispatch algorithm with transient stability constraints increasingly important for the transparent power system operation. Heuristic and off-line evaluation for the operation point can produce a discrimination among market players in the deregulated power system. In this paper, a dispatch algorithm with transient stability constraints is proposed. Energy margin under the TEF(Transient Energy Function) structure is adopted as a measure for the stability index. Implementation issues and simulation results are discussed in the context of a 10-bus system

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2018.11a
• /
• pp.553-554
• /
• 2018

• Proceedings of the KIEE Conference
• /
• 2005.10b
• /
• pp.20-22
• /
• 2005

In this paper, we propose a novel stability criterion for switched linear systems. The proposed method employs the results on the upper bound of the solution of LME(Lyapunov Matrix Equation) and on the stability of hybrid system. The former guarantees the existence of Lyapunov-like energy functions and the latter shows that the stability of switched linear systems by using these energy functions. The proposed criterion releases the restriction on the stability of switched linear systems comparing with the existing methods and provides us with easy implementation way for pole assignment.

• Transactions of the Korean hydrogen and new energy society
• /
• v.34 no.5
• /
• pp.389-397
• /
• 2023

This study compares domestic and foreign research on renewable energy-based water electrolysis clean hydrogen. Domestic studies from 2010 to 2023 focused on technological efficiency, energy efficiency, and system efficiency, with few analyzing infrastructure and technology trends. Overseas research initially focused on technological efficiency and stability, but has since shifted to economic and environmental impact, policy effectiveness, industry-university-research cooperation, and sustainability. To improve water electrolysis technology production, this study suggests prioritizing technology stability over efficiency, resolving government regulations and resident acceptance issues, promoting industry-university-institute cooperation for rapid commercialization of research results, and developing a strategy for sustainable development of renewable energy-based water electrolysis technology.

• 한국HCI학회:학술대회논문집
• /
• 2009.02a
• /
• pp.2068-2071
• /
• 2009

This paper presents a multiple degree-of-freedom (dof) energy bounding approach (EBA) to enhance directional transparency while guaranteeing stability for multiple-dof haptic interaction. It was observed that the passivity condition for multiple ports may lead to some oscillatory limit cycle behaviors in some coordinate directions even though the total sum of energy flow-in is positive, meaning that the system is passive. The passivity condition, therefore, needs to be applied to each coordinate in order to avoid oscillatory behavior by keeping each energy flow-in always positive. For guaranteeing passivity, which in turn, stability in each coordinates, the EBA is applied. For multiple-dof haptic interaction, however, the EBA in each coordinate may distort the direction of the force vector to be rendered since the EBA may cut down the magnitude of the force and torque vectors to be rendered in order to ensure the passivity. For avoiding this problem, a simple projection method is presented. The validity of the proposed algorithm is shown by several experiments.

• Wind and Structures
• /
• v.30 no.5
• /
• pp.511-524
• /
• 2020

Advancements in materialistic life styles and increasing awareness about adverse climatic changes and its negative effects on human life have been the driving force of finding new and clean sources of energy. Wind power has become technologically mature and commercially acceptable on global scale. However, fossil fuels have been the major sources of energy in most countries, renewable energy (particularly wind) is now booming worldwide. To cope with this wind energy technology, various related aspects have to be understood by the scientific, engineering, utility, and contracting communities. This study is an effort towards the understanding of the (i) wind turbine blade and tower structural stability issues, (ii) turbine blade and tower failures and remedial measures, (iii) weather and seismic effects on turbine blade and tower failures, (iv) gear box failures, and (v) turbine blade and tower failure analysis tools.

• Journal of Electrical Engineering and Technology
• /
• v.3 no.4
• /
• pp.468-475
• /
• 2008

This paper presents a method for estimating the transient stability status of the power system using radial basis function(RBF) neural network with a fast hybrid training approach. A normalized transient energy margin(${\Delta}V_n$) has been obtained by the potential energy boundary surface(PEBS) method along with a time-domain simulation technique, and is used as an output of the RBF neural network. The RBF neural network is then trained to map the operating conditions of the power system to the ${\Delta}V_n$, which provides a measure of the transient stability of the power system. The proposed approach has been successfully applied to the 10-machine 39-bus New England test system, and the results are given.

• Journal of Korean Association for Spatial Structures
• /
• v.15 no.4
• /
• pp.49-56
• /
• 2015

The roof grid of single-layer space frame structure, for Energy Core of Incheon Airport Second Terminal, is very simple and aesthetic, but it is apt to buckle under external force because of mild curvature and complex shape. The object of this study is to estimate the stability of single-layer space frame structures for Energy Core of Incheon Airport Second Terminal with the analytical conditions of structural design. The results show that the buckling load of model(pin-pin, uniform load, rigid joint), that is, the most similar model to the analytical conditions of structural design. was $10.7kN/m^2$.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.11 no.4
• /
• pp.5-8
• /
• 1974

In this paper, several criterias of Lyapunov, Malkin, Popov, etc. about stability of nonlinear systems are compared, and study on methods, through several examples, of judging the stability of nonlinear systems by considering the energy input into the system and the one put out of the system is concentrated.

• Bulletin of the Korean Mathematical Society
• /
• v.54 no.1
• /
• pp.145-158
• /
• 2017

We present a finite difference method for solving the Ohta-Kawasaki model, representing a model of mesoscopic phase separation for the block copolymer. The numerical methods for solving the Ohta-Kawasaki model need to inherit the mass conservation and energy dissipation properties. We prove these characteristic properties and solvability and unconditionally gradient stability of the scheme by using Hessian matrices of a discrete functional. We present numerical results that validate the mass conservation, and energy dissipation, and unconditional stability of the method.