• Journal of the Korean Institute of Intelligent Systems
• /
• v.11 no.7
• /
• pp.603-610
• /
• 2001

Industrial processes are normally operated by skilled humans who have the cumulative and logical information about the system. Fuzzy control has been investigated for many application. Intelligent control approaches based on fuzzy logic have a chance to include human thinking. This paper represents modeling approach based upon operators knowledge without mathematical model of the system and optimize the controller. The experimented system is constructed for sending a ball to the goal position using wind of two DC motors in the predefined path. A vision camera to mimic human eyes detects the ball position. The system used in this experiment could be hardly modeled by mathematical methods and ould not be easily controlled by conventional manners. The controller is designed based on the input-output data and experimental knowledge obtained by trials, and optimized under the predefined performance criterion. And this paper shows the data adaptation for changeable operating condition. When the system is driven in the abnormal condition with unconsidered noise, the new optimal operating parameters could be defined by adjusting membership functions. Thus, this technique could be applied in industrial fields.

• Membrane Journal
• /
• v.13 no.4
• /
• pp.219-228
• /
• 2003

This study was carried to investigate the effect of humic acid and kaloin which cause the turbidity and organic substance component for optimization of drinking water treatment process using the membrane separation. Also we were ovserved the optimum operating condition which flux was stabilized, while specific resistance value in membrane was minimized. As the result, the membrane separation was operated at low specific resistance value with the increase of the pressure. And then, cake load decreased by high velocity with the increase of the linear velocity, and the tendency in which specific resistance value and flux increased. Therefore, we confirmed the optimum operating condition as pressure $2.0 kgf/cm^2,$ 0.92 m/sec linear velocity.

• Korean Chemical Engineering Research
• /
• v.46 no.4
• /
• pp.739-746
• /
• 2008

The aim of this study is finding the optimal design parameters and the optimal operation variables of a reactive distillation column. Different from steady state optimization, dynamic optimization makes it possible considering operation ability as well as design problems at process design step. For performing dynamic optimization, dynamic simulation should be done first. If dynamic simulation is already finished, dynamic optimization can be performed with less effort than that of dynamic simulation.Reactive distillation systems involving reaction and separation in a single unit have the potential to reduce capital and operating costs, particularly when reaction have conversion constraint or when azeotropes exist making conventional separation difficult and expensive. This study here present work on the continuous distillation process, the homogeneous catalyzed esterification of methanol and acetic acid, the synthesis of methyl acetate. Based on an equilibrium stage model of a reactive distillation column a dynamic optimization problem was formulated and solved. And the results were verified by performing dynamic simulation and showing the variation of conversion and purity as the variation of the operation variables. As the results of dynamic optimization, this study found optimal feed ratio, reflux ratio and reboiler duty of this system. And as this study applied it to dynamic simulations the dynamic characteristics of a reactive distillation column are showed under optimal operating condition.

• Journal of rehabilitation welfare engineering & assistive technology
• /
• v.7 no.2
• /
• pp.41-46
• /
• 2013

IIn this paper, active trasfemoral prosthesis leg is designed for the handicapped who lost their legs upon knee. It is important to design proper knee joint to mimic walking motion of hyman. 1 degree-of-freedom active trasfemoral prosthesis leg is designed with knee joint. Operating angle and torque have been calculated using kinematics of three linkages in prosthesis leg. Finite element analysis of major components is performed to evaluate the safety under operating condition and to reduce weights. Minimum volumes of components are obtained by optimization as satisfying safety requirements. The results show that about 35% of weight of components is reduced.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.18 no.5
• /
• pp.62-67
• /
• 2010

Exhausting fossil fuel and increasing concern of air pollution have brought on the change of the focus of developing new vehicles from performance to fuel economy and emission. The gasoline engines adopting the naturally aspirated way use the throttle-body for engine load control. Therefore, its pumping loss increases more than that of the diesel engine, and also mostly operating in a partial load condition has bad influence on fuel economy and emission. In these days, the continuous variable valve timing system and variable induction system are adopted in order to improve fuel consumption and emission. In this study, we optimize the runner length and operate region of variable induction system to simulataneously improve the performance, fuel economy, and emission of gasoline engine with employing GT-Power as a CAE tool for engine analysis and PIAnO as PIDO tool for process integration and design optimization.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.581-584
• /
• 2005

A district heating(DH) system supplies environmentally-friend heat and is appropriate for reduction of energy consumption and/or air pollutions. The objectives of this paper are to systematize data processing of transition temperature, investigate its effects on fatigue life of DH pipes and optimization for size of DH pipes. A relational database management system as well as reliable fatigue life evaluation procedures is established for Korean DH pipes. Also, since the prototypal evaluation results satisfied both cycle-based and stress-based fatigue criteria. Through the optimum design process, the cross section diminished 18.64% and the CUF diminished 23.35%. So, it can be used as useful information in the future for optimal design, operation and energy saving via setting of efficient condition and stabilization of water temperature.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.39 no.7
• /
• pp.653-667
• /
• 1990

Superconductor is consolidated, for required current capacity, with proper numbers of basic strands which are multifilamentary composites. Althouth superconductors are perfectly loss-free under DC conditions of current and field, AC losses occur under time-varying condition of the current and field. The AC losses are a controllable inherent characteristics of supercondectors. The AC losses dependent on the changing rate of current and field can be reduced by reducing the filament diameter. On the other hand, finer filament results in manufacturing cost increase. Therefore, in this paper optimization technique of superconductor for SMES is proposed from the viewpoint of AC loss reduction and manufacturing cost increase. The case study shows that the technique can be effectively used for the design of superconductor for SMES, appreciating the influence of various parameters related to superconductor itself and operating condition of SMES. As a result of the case study, it is confirmed that the technique is more effective for the design of superconductor for SMES for electric power power system stabilization rather then SMES for energy storage.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.50 no.8
• /
• pp.388-394
• /
• 2001

This paper presents how to determine the optimal operating points of Unified Power Flow controllers (UPFC) the line flow control of which can enhance system security level. In order to analyze the effect of these devices on the power system, the decoupled model has been employed as a mathematical model of UPFC for power flow analysis. The security index that indicates the level of congestion of transmission line has been proposed and minimized by iterative method. The sensitivity of objective function for control variables of and UPFC has been derived, and it represents the change in the security index for a given set of changes in real power outputs of UPFC. The proposed algorithm with sensitivity analysis gives the optimal set of operating points of multiple UPECs that reduces the index or increases the security margin and Marquart method has been adopted as an optimization method because of stable convergence. The algorithm is verified by the 10-unit 39-bus New England system that includes multiple FACTS devices. The simulation results show that the power flow congestion can be relieved in normal state and the security margin can be guaranteed even in a fault condition by the cooperative operation of multiple UPECs.

• Bulletin of the Korean Mathematical Society
• /
• v.48 no.3
• /
• pp.523-537
• /
• 2011

A receiver operating characteristic (ROC) curve plots the true positive rate of a classier against its false positive rate, both of which are accuracy measures of the classier. The ROC curve has several interesting geometrical properties, including concavity which is a necessary condition for a classier to be optimal. In this paper, we study the nonparametric maximum likelihood estimator (NPMLE) of a concave ROC curve and its modification to reduce bias. We characterize the NPMLE as a solution to a geometric programming, a special type of a mathematical optimization problem. We find that the NPMLE is close to the convex hull of the empirical ROC curve and, thus, has smaller variance but positive bias at a given false positive rate. To reduce the bias, we propose a modification of the NPMLE which minimizes the $L_1$ distance from the empirical ROC curve. We numerically compare the finite sample performance of three estimators, the empirical ROC curve, the NMPLE, and the modified NPMLE. Finally, we apply the estimators to estimating the optimal ROC curve of the variance-threshold classier to segment a low depth of field image and to finding a diagnostic tool with multiple tests for detection of hemophilia A carrier.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.20 no.4
• /
• pp.452-457
• /
• 2011

The internal temperature of an operating room had to keep within $20^{\circ}C$. However, the doctor who is wearing operating gown and mask caused to rise temperature because of the thermal occurrence of dental LED light source. At first, the surgery environment is getting worse. And then last, it would increase bleeding rate by the expansion of patient's exposured blood vessel. A surgical operator can distribute the patient's tissue through such surgery environment, exactly. It can do accurate surgery. So, it gave to effect that surgical operator's eye condition is getting better and it could keep a mutual assistance system. For this research, we develop the LED dental light source module of high color rendition. It performed simulation for replacing established the method of Halogen lamp and Plazma lamp of light source. We analyzed intensity of illumination and the change of viability by changing the height of light source module.