• Journal of the Institute of Convergence Signal Processing
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• v.2 no.3
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• pp.73-78
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• 2001

BP neural network model and multiple-regression model were composed for forecasting the special-days load. Special-days load was forecasted using that neural network model made use of pattern conversion ratio and multiple-regression made use of weekday-change ratio. This methods identified the suitable as that special-days load of short and long term was forecasted with the weekly average percentage error of 1∼2[%] in the weekly peak load forecasting model using pattern conversion ratio. But this methods were hard with special-days load forecasting of summertime. therefore it was forecasted with the multiple-regression models. This models were used to the weekday-change ratio, and the temperature-humidity and discomfort-index as explanatory variable. This methods identified the suitable as that compared forecasting result of weekday load with forecasting result of special-days load because months average percentage error was alike. And, the fit of the presented forecast models using statistical tests had been proved. Big difficult problem of peak load forecasting had been solved that because identified the fit of the methods of special-days load forecasting in the paper presented.

• Geomechanics and Engineering
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• v.10 no.5
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• pp.599-615
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• 2016

The present research presents experimental and finite element studies to investigate the behavior of piled raft-tunnel system in a sandy soil. In the experimental work, a small scale model was tested in a sand box with load applied vertically to the raft through a hydraulic jack. Five configurations of piles were tested in the laboratory. The effects of pile length (L), number of piles in the group and the clearance distance between pile tip and top of tunnel surface (H) on the load carrying capacity of the piled raft-tunnel system are investigated. The load sharing percent between piles and rafts are included in the load-settlement presentation. The experimental work on piled raft-tunnel system yielded that all piles in the group carry the same fraction of load. The load carrying capacity of the piled raft-tunnel model was increased with increasing (L) for variable (H) distances and decreased with increasing (H) for constant pile lengths. The total load carrying capacity of the piled raft-tunnel model decreases with decreasing number of piles in the group. The total load carrying capacity of the piles relative to the total applied load (piles share) increases with increasing (L) and the number of piles in the group. The increase in (L/H) ratio for variable (H) distance and number of piles leads to an increase in piles share. ANSYS finite element program is used to model and analyze the piled raft-tunnel system. A three dimensional analysis with elastoplastic soil model is carried out. The obtained results revealed that the finite element method and the experimental modeling are rationally agreed.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.1
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• pp.63-66
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• 1995

PID controller is being used in many servo control system. However, when a control system has variable load, it is difficult to guarantee the accurate control of the system. In the way of solving this problem, in this paper, a auto-tuning method of PID controller parameter using fuzzy rule in variable load is presented. The parameter of PID controller are decided by fuzzy rule according to load variation. The accurate control function of fuzzy auto-tuning is demonstrated by simulation.

• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.41-43
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• 2008

This paper presents the characteristic analysis of Double-Sided Linear Synchronous Generator for wave power generation under different operating conditions. FEM is applied to analyze performance of generator at no-load and load with variable resistance. Moreover, the validity of characteristic analysis is confirmed through the experimental work.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.389-391
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• 1994

This paper proposes an approach to control the current amplitude and phase simultaneously. To do this, variable structure control and adaptive parameter estimation arc applied to the current control of a single-phase PWM inverter with unknown R-L series load. The load parameters, R and L, are estimated by using the recursive least square method and these parameters are used to adjust the feedback gains of control input. The inverter system is modelled in a 2nd-order system by treating load current variation caused by inductive component as a disturbance. Simulation and experiment based on the 2nd -order model are done and the results show good dynamic response and low THD.

• Structural Engineering and Mechanics
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• v.46 no.2
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• pp.269-294
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• 2013

This paper is concerned with the determination of exact buckling loads and vibration frequencies of variable thickness isotropic plates using well known finite difference technique. The plates are subjected to uni, biaxial compression and shear loadings and various combinations of boundary conditions are considered. The buckling load is found out as the in plane load that makes the determinant of the stiffness matrix equal to zero and the natural frequencies are found out by carrying out eigenvalue analysis of stiffness and mass matrices. New and exact results are given for many cases and the results are in close agreement with the published results. In this paper, like finite element method, finite difference method is applied in a very simple manner and the application of boundary conditions is also automatic.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.2
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• pp.137-143
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• 2003

In the forming of an integrated system of radiant floor cooling and dehumidifying, chilled coil can be used for cooling and dehumidification. Therefore, it is necessary to find the efficient control method which can eliminates latent load efficiently. This study has been conducted to find this method by dividing the dehumidification system into 3 types according to the control variables and analyzing characteristics of each system. To prevent the floor surface condensation, the amount of condensation can be manipulated by water temperatures, water flow rates in chilled coil, and air flow rates passing by it. So dehumidification system control can be divided into constant air flow control and variable air flow control. Regarding dehumidification control, variable air flow control, which eliminates latent load rather than sensible load, is preferable to constant flow control.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.10
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• pp.1-7
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• 1992

This paper proposes reservation-based multiple access with variable frame length (RMAV) which is a new multiple access scheme for indoor and outdoor wireless data communications. RMAV is based on the slot reservation scheme and adopts a frame structure with variable frame length. The frame length increases as the number of active terminals and/or the system load increases. As a result, RMAV is adapted to the changes in the traffic pattern, and it offers short delay in light load conditions and high throughput in heavy load conditions. The performance of RMAV is evaluated by simulations. In addition, it is compared with the performance of PRMA(packet reservation multiple access).

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.687-692
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• 1990

The purpose of this study is ID form the required force for measurements of the performances of the equipments or testpieces. For the generation of the required force, ft difference of pressures in each chamber of the hydraulic cylinder was controlled and Variable Structure Control theory was adopted to control it. Besides, observers -Luenberger Observer and nonlinear Variable Structure Observer - were designed to estimate the derivative of the load pressure which is necessary ID determine the sliding surface in VSC theory. As a consequence of the computer simulation, it was shown that VSC had better performance than classical control theory(P, PD control) and VSO performed better than the Luenberger Observer at the load pressure control.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.121-123
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• 2002

This paper presents the finite-element (FE) analysis results of a permanent-magnet (PM) generator for wind-power applications under different operating conditions. Finite-element method is applied to analyze generator performance at no-load and load with variable resistance and inductance. The results of FE analysis show that proposed PM generator is a useful solution for small-scale wind-turbine systems.