• Journal of Institute of Control, Robotics and Systems
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• v.6 no.12
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• pp.1070-1078
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• 2000

A nonlinear adaptive flight control system is proposed using a backstepping controller with neural network controller. The backstepping controller is used to stabilize all state variables simultaneously without the two-timescale assumption that separates the fast dynamics, involving the angular rates of the aircraft, from the slow dynamics which includes angle of attack, sideslip angle, and bank angle. It is assumed that the aerodynamic coefficients include uncertainty, and an adaptive controller based on neural networks is used to compensate for the effect of the aerodynamic modeling error. It is shown by the Lyapunov stability theorem that the tracking errors and the weights of neural networks exponentially converge to a compact set. Finally, nonlinear six-degree-of-freedom simulation results for an F-16 aircraft model are presented to demonstrate the effectiveness of the proposed control law.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.3
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• pp.267-274
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• 1999

This paper proposes an adaptive sliding mode control scheme for an autopilot design of Skid-to-Turn (STT) missiles. The feedback linearization controller eliminates nonlinear terms in STT dynamics and makes the entire system linear. But the modeling errors in dynamics and the external disturbances exert bad influence on the performance of the feedback linearization controller. To handle these uncertainties, an adaptive control scheme is developed, where a bound of the uncertainties is estimated by an adaptive law based on a sliding surface. The asymptotic output tracking is proved by using the Lyapunov stability theory. Simulations for STT missiles illustrate the validity of the proposed scheme.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.5
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• pp.305-308
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• 2004

The 7-dial inductive voltage divider(IVD) for application at low frequency range which can precisely divide the in put voltage up to resolution of $10^{-7}$ was fabricated by using the toroidal cores made by super-mumetal strips of 0.025 mm thick and special decade switches. The cores have the initial permeability of 200.000 and magnetic flux density of 0.5 T. The inphase and quadrature ratio errors for a fabricated 7-dial IVD are found to be less than $\pm$4${\times}$$10^{-7}$ and $\pm$5${\times}$$10^{-6}$ rad(k=2), respectively. by calibration using the IVD calibration system of KRISS. The fabrication techniques used and uncertainty evaluation are discussed in this paper.

• Korean Management Science Review
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• v.15 no.2
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• pp.211-227
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• 1998

The process of implementing risk management systems for the organizations in financial service industry can be viewed as a diffusion of innovation since the introduction of the risk management systems changes the decision making process on risks faced by the organizations. The purpose of the reported research is to examine the factors that affect the successful implementation of ALM(asset & liability management) systems, the risk management systems managing interest rate risk. Specifically, this paper presents an investigation of three factors from the diffusion of innovation studies; internal factors, external factors, and time. A field survey was conducted for Korean banks that have implemented ALM systems. The results suggest that the perceived uncertainty of market, system supports, and management supports be most significantly related to the successful implementation of the risk management systems. The findings of the current study also suggest a certain amount of time should be passed to diffuse the risk management systems in organizations.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.319-324
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• 2003

There is much more possibilities of encounter of critical problems and uncertain factors in construction project it is very important to analyze various risk factors of the project in its first stage. Because of the uncertainty, we need to study about the construction insurance scheme for risk-transfer within construction management method. This research methodology has been devised through analysis of characteristic of classified domestic construction insurance as well as some related foreign insurance system.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.1
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• pp.155-169
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• 2001

In this paper, dynamic pressure is mainly generated in the closed chamber of gun when the propellant is fired and has exponential pressure motion. Dynamic pressure calibrator with positive step pressure was designed and manufactured to meet the calibration of piezoelectric high pressure transducers which are mainly used to measure dynamic pressure motion in the test of weapon systems. In addition, the results of Performance test and analysis of system uncertainty are provided.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.3
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• pp.233-240
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• 2006

This paper presents the robust control method using a self recurrent wavelet neural network (SRWNN) via adaptive backstepping design technique for stable walking of biped robots with unknown model uncertainties. The SRWNN, which has the properties such as fast convergence and simple structure, is used as the uncertainty observer of the biped robots. The adaptation laws for weights of the SRWNN and reconstruction error compensator are induced from the Lyapunov stability theorem, which are used for on-line controlling biped robots. Computer simulations of a five-link biped robot with unknown model uncertainties verify the validity of the proposed control system.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.6
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• pp.425-434
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• 2003

The disturbance observer(DOB) has been widely used in high speed and high precision motion control applications and the characteristics of DOB have been investigated in depth. Though most of DOB's have been implemented as the discrete-time form in digital devices, we are still short of the researches on discrete-time DOB (DDOB) in spite of rich references on continuous-time DOB. In this paper, we discuss about the disturbance rejection property and measurement noise effect of discrete-time DOB. Especially, we will focus on revealing the role of sampling time in designing the discrete-time DOB and show the validity of analysis through simulations and experiments for optical disk drive systems.

• Korean Institute of Interior Design Journal
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• v.15 no.5 s.58
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• pp.289-297
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• 2006

This study was begun on the premise that architecture which has the definite disposition for survival even in the urban, social structure of that uncertainty and constructs specialty is biomorphic architecture. This study was made with the following four specific purposes largely. First, through the theoretical investigation of biomorphic architecture that appears in the tendency that mordern architecture develops into the architecture of do-stereotype and new form, its meaning and definition are examined. Second, the analysis of biomorphic architecture is investigated and the generation causes are applied architecturally and generate biomorphic architecture is made. Third, by analyzing the material expression characteristics of biomorphic architecture, the meaning and possibility of architecture, which expresses the vitality of organism, as the material expression characteristics of biomorphic architecture, are investigated. The material expression characteristics was deduced through the generation background of biomorphic architecture. The material expression characteristics of biomorphic architecture is the various modeling by smart-network and the response system of sensitivity poly-logue.

• Journal of Korean Institute of Industrial Engineers
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• v.17 no.1
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• pp.51-58
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• 1991

This paper presents a single-echelon, single item, stochastic lead time and static demand inventory model for situations in which, during the stockout period, a fraction ${\beta}$ of the demand is backordered and the remaining fraction $(1-{\beta})$ is lost. In this situations, an objective function representing the average annual cost of inventory system is obtained by defining a time-proportional backorder cost and a fixed penalty cost per unit lost. The optimal operating policy variables minimizing the average annual cost are calculated iteratively. At the extremet ${\beta}=1$, the model presented reduces to the usual backorder case. A numerical example is solved to illustrate the algorithm developed.