• Journal of the Korean Operations Research and Management Science Society
• /
• v.36 no.1
• /
• pp.69-84
• /
• 2011

In this study, based on the principal-agent paradigm, we investigate a joint cost reduction activity in a buyer-supplier supply chain where a buyer motivates its operations department and a supplier to reduce the supply chain's production cost. We construct a benefit-sharing model based on the target cost scheme, a basic philosophy in practice which has not been explored in previous studies. The model also incorporates various supply chain issues such as the cooperation of multiple agents, the opportunity loss, and the degree of strategic relationship between the buyer and the supplier. Based on the analysis of the principal-agent model, we investigate the benefit-sharing rule to control agents' actions, and we also provide important managerial implications into supply chain practices via extensive comparative static analyses.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.36 no.6
• /
• pp.381-389
• /
• 1987

This paper presents a method for optimal load shedding in preserving a system security following abnormal condition as well as a sudden major supply outage. The method takes account of static characteristic of generators control and voltage and system frequency characteristic of loads. The optimization problem is solved by a gradient technique to get the maximal effect by the least quantity of load shedding considering line overloads as well as voltage disturbances and system frequency. The method is illustrated on a 8-bus system. It has been found that the use of the proposed algorithm for model systems alleviate the line overload more efficiently than the former method. It is believed that this method will be useful in security studies and operational planning.

• Nuclear Engineering and Technology
• /
• v.19 no.4
• /
• pp.279-291
• /
• 1987

The event tree/fault tree techniques used in the current probabilistic risk assessment (PRA) of nuclear power plants are based on the binary and static description of the components and the system. While these techniques Bay be adequate in most of the safety studies, more advanced techniques, e.g., the Markov reliability analysis, are required to accurately study such problems as the plant availability assessments and technical specifications evaluations that are becoming increasingly important. This paper describes a Markov model for the Reactor Protection System of a pressurized water reactor and presents results of model evaluations for two testing policies in technical specifications.

• International Journal of Control, Automation, and Systems
• /
• v.4 no.4
• /
• pp.466-479
• /
• 2006

This paper addresses a formation navigation issue for a group of mobile robots passing through an environment with either static or moving obstacles meanwhile keeping a fixed formation shape. Based on Lyapunov function and graph theory, a NN formation control is proposed, which guarantees to maintain a formation if the formation pattern is $C^k,\;k\geq1$. In the process of navigation, the leader can generate a proper trajectory to lead formation and avoid moving obstacles according to the obtained information. An evolutionary computational technique using particle swarm optimization (PSO) is proposed for motion planning so that the formation is kept as $C^1$ function. The simulation results demonstrate that this algorithm is effective and the experimental studies validate the formation ability of the multiple mobile robots system.

• Journal of Institute of Control, Robotics and Systems
• /
• v.13 no.4
• /
• pp.377-384
• /
• 2007

This paper studies on the relation between linearization methods and controller gains in the looper ILQ(lnverse Linear Quadratic optimal control) system for hot strip finishing mills. Firstly, two linear models arc respectively derived by a linearization method using Taylor's series expansion and a static state feedback linearization method, respectively, and the linear models are compared with the nonlinear model. Secondly, the looper servo controllers are respectively designed on the basis of two linearization models. Finally, the relation between the performances of two ILQ servo controllers and the linearization methods, and the structures and control gains of two controllers are evaluated by a computer simulation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.05a
• /
• pp.215-218
• /
• 2009

A design of a subscale solid propellant rocket motor was conducted to do the similitude experiments for the large scale rocket motor. One of the main factor to subscale was the mach number of the solid propellant flume through a nozzle exit The analysis of the flume flow was done to obtain the mach number for the large and subscale rocket motor. The flume shapes on the non dimensional axises by the nozzle exit diameter was matched each other. The propellant grain of a subscale solid rocket motor was designed by the profile of pressure vs time obtained by the mach number of the flume shape. Some analyses of the theoretical solution were compared with the results of the ground static test.

• Wind and Structures
• /
• v.8 no.2
• /
• pp.135-146
• /
• 2005

Divergent galloping-like motion of a dry inclined cable has been observed in a limited number of experimental studies, which, due to the uncertainties in its onset conditions, has induced serious concerns in the bridge stay cable design. A series of dynamic and static model wind tunnel tests have been carried out to confirm the existence of the phenomenon and clarify its excitation mechanism. The present paper focuses on exploring the spatial flow structure around an inclined cable. The pattern of resultant aerodynamic forces acting at different longitudinal locations of the model and the spatial correlation of the forces are examined. The results lead one step closer in revealing the physical nature of the phenomenon.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2009.05a
• /
• pp.189-190
• /
• 2009

This paper studies the lateral response of reinforced concrete columns strengthened with carbon fiber reinforced polymer sheet (CFRP) subjected to static loading analytically by comparing with experimental results. For interface behavior between RC columns and CFRP, and interface element in FEM was applied and verified its performance by analyzing lateral behavior of RC columns strengthened with CFRP. The comparison shows that the proposed analytical method is effective for nonlinear analysis of RC columns strengthened CFRP.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.04a
• /
• pp.177-184
• /
• 2008

Vehicle body frame stiffness affects the dynamic and static characteristics. Vehicle frame structure performance is greatly affected by crossmember and joint design. While the structural characteristic of these joint vary widely, there is no known tool currently in use that quickly predicts joint stiffness early in design cycle. This paper present the joint design factors affecting on low frequency vibration. The joint factors are joint panel thickness, flange width and weld point space. To study the effect on vehicle low frequency vibration, case studies for these factors are performed. The result can present design guide for high-stiffness vehicle.

• Proceedings of the KIEE Conference
• /
• 1999.07c
• /
• pp.1401-1403
• /
• 1999

This paper presents a distance relaying algorithm for transmission line compensated with Static Synchronous Series Compensator (SSSC). The compensation voltage driven by SSSC is calculated from the line current measured at a relaying point Then the compensation voltage is subtracted from the voltage measured by the relay. We can apply conventional distance relaying algorithm with this subtracted voltage to locate a fault. The results of case studies using EMTP (Electro-Magnetic Transient Program) show the proposed algorithm has higher precision.