• Proceedings of the KAIS Fall Conference
• /
• 2009.12a
• /
• pp.633-635
• /
• 2009

It is a quite quality concerning to control temperature of single crystalline growth as it does when you get most of heat treating products. It is also important factor to control temperature when you make the $Al_2O_3$(single crystalline) used to artificial jewels, glass of watches, heat resistant transparent glasses. Thus, it is a major interest to get the proper temperature in accordance with the time process while you are making mixture of oxygen and hydrogen to have the right temperature. In this paper, we will study of electrical valve positioning system for the gas mixture to improve the quality of products.

• Proceedings of the KIEE Conference
• /
• 2000.07a
• /
• pp.110-112
• /
• 2000

A new robust digital fuzzy controller design methodology is proposed for load frequency of nonlinear power system with valve position limits of governor in the presence of parametric uncertainties. The Takagi-Sugeno (TS) fuzzy model is adopted for fuzzy modeling of the nonlinear power system. A sufficient condition of robust stability for robust fuzzy control with parametric uncertainties is presented in the sense of Lyapunov. The controller that designed by preposed robust fuzzy controller design method is based compounding condition between continues system and discrete system. The effectiveness of controller that designed by the proposed robust fuzzy controller design method is demonstrated through simulation example.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2000.05a
• /
• pp.142-145
• /
• 2000

A new robust load-frequency control (LFC) methodology is proposed for nonlinear power systems with the valve position limits of the governor in the presence of parametric uncertainties. The Takagi-Sugeno (TS) fuzzy model is adopted for fuzzy modeling of the nonlinear power system. A sufficient condition of the robust stability is presented in the sense of Lyapunov for the TS fuzzy model with parametric uncertainties. The intelligent digital redesign technique for the uncertain nonlinear power system is also studied. The effectiveness of the proposed robust fuzzy LFC controller design method is demonstrated through a numerical simulation.

• Proceedings of the KIEE Conference
• /
• 2007.10a
• /
• pp.277-278
• /
• 2007

본 논문은 HVAC(heating, ventilating, and air conditioning) 시스템에 대해 Particle Swarm Optimization(PSO) 알고리즘을 이용하여 최적화된 Multi-Fuzzy 제어기 설계를 제안한다. HVAC 시스템의 효율과 안정도에 결정적인 영향을 미치는 과열도와 저압(증발기의 압력)을 제어하기 위해, 3대의 Expansion Valve 와 1대의 Compressor 에서 동시에 제어하는 Multi-Fuzzy 제어기를 설계한다. 그리고 최적화 알고리즘 중 하나인 사회적인 행동양식을 기반한 PSO 알고리즘을 이용하여 설계된 Multi-Fuzzy 제어기를 최적화한다. 시뮬레이션의 결과 비교를 통해, 대표적인 최적화 알고리즘인 유전자 알고리즘을 사용한 최적화된 제어기와 제안한 PSO 알고리즘을 이용한 최적화된 제어기의 성능을 평가한다.

• Journal of Veterinary Clinics
• /
• v.38 no.5
• /
• pp.215-220
• /
• 2021

The purpose of this study was to investigate the correlation between vertebral left atrial size (VLAS) and NT-proBNP levels. Sixty-three dogs with myxomatous mitral valve disease (MMVD) were recruited for this study. The MMVD group was classified according to the ACVIM stage based on medical history, clinical signs, and thoracic radiography and echocardiography findings. The N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels were measured using fluorescent immunoassay. VLAS and VHS values were measured using a digital caliper in the right lateral view. There were significant differences in VLAS for each American college of veterinary internal medicine (ACVIM) stage (p < 0.01). As the ACVIM stage increased, it tended to increase. Vertebral heart score (VHS) also showed a tendency to increase with the ACVIM stage (p < 0.01). VLAS was divided into three groups: VLAS <2.6, 2.6≤ VLAS <3.1, and VLAS ≥3.1. NT-proBNP values were significantly different between the three groups (p < 0.01), and VLAS and NT-proBNP values showed a strong positive correlation (r = 0.756, p < 0.01). In conclusion, there were significant differences among ACVIM stages B1 and B2, B1 and C-D, and B2 and C-D groups regarding VLAS. Furthermore, NT-proBNP increased proportionally as VLAS increased. Measurements of VLAS may be helpful in the diagnosis of MMVD in addition to the existing radiological and echocardiographic methods.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.10 no.4
• /
• pp.357-367
• /
• 2000

A new robust load-frequency control methodology is proposed for nonlinear power systems with valve position limits of the governor in the presence of parametric uncertaines. The TSK fuzzy model is adopted and formulated for fuzzy modeling of the nonlinear power system. A sufficient condition of the robust stabilitry is presented in the sense of lyapunov for the TSK model with parametric uncertainties. The intekkigent digital redesign technique for the uncertain power systems is also studied. The effectiveness of the robust digital fuzzy controller disign mothod is demonstrated through a numerical simulation.

• Journal of Hydrogen and New Energy
• /
• v.17 no.2
• /
• pp.193-203
• /
• 2006

A high-speed and initial helium jet flow has been analyzed by a developed four-dimensional digital speckle tomography. Multiple high-speed cameras have been used to capture movements of speckles in multiple angles of view simultaneously because a shape of a nozzle for the jet flow is asymmetric and the initial jet flow is fast and unsteady. The speckle movements between no flow and helium jet flow from the asymmetric nozzle controlled by a solenoid valve have been obtained by a cross-correlation tracking method so that those distances can be transferred to deflection angles of laser rays for density gradients. The four-dimensional density fields for the high-speed helium jet flow have been reconstructed from the deflection angles by a developed real-time tomography method.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.15 no.6
• /
• pp.454-460
• /
• 2003

In order to investigate the cooling and heating characteristics of a variable-capacity system A/C applying a digital scroll compressor, the cooling and heating capacities and COP are measured by the psychrometric calorimeter. The capacity of the system is controlled by the digital scroll compressor, which is operated by controling PWM valve and the loading vs. unloading time. In the case of unloading compared that of loading, the consumption power of the compressor is about 11% and the capacity variation of the system A/C is within about 1%. When the system A/C is operated under the cooling and heating standard conditions, COP is nearly uniform but cooling capacity and heating capacity increase at minimum, rated and maximum modes. The system A/C applying the digital scroll compressor is effective for the range with high load or the width of large load variation. When the auxiliary heater is on, at the cold region, the system A/C produces the excellent heating capacity.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.16 no.6
• /
• pp.1036-1055
• /
• 1992

In this paper the feedback linearization of the valve-controlled nonlinear hydraulic velocity control system and the implementation of the digital state feedback controller is studied. The $C^{\infty}$ nonlinear transfomation to the electro-hydraulic velocity control system, which transforms nonlinear system to linear equivalent one, is obtained. It is shown that this transformation is global one. The digital controller to this linearized model is obtained by using the one-step ahead state estimator and implemented to real plant. The proposed implementation method is easier than the other proposed methods and it is possible to control in real time. The experiment and simulation study show that the implementation of the digital state feedback controller based on the feedback linearized model is successful..

• Industrial Engineering and Management Systems
• /
• v.10 no.2
• /
• pp.161-169
• /
• 2011

In seeking further efficiency in production preparation, it is common to examine assembly sequences using digital manufacturing. The assembly sequences affect the product evaluation, so it is necessary to test several assembly sequences before actual production. However, because selection and testing of assembly sequences depends on the operator's personal experience and intuition, only a small number of assembly sequences are actually tested. Nevertheless, there is a systematic method for generating assembly sequences using a contact-related figure. However, the larger the number of parts, the larger the number of assembly sequences geometric becomes. The purpose of this study is to establish a systematic method of generating efficient assembly sequences regardless of the number of parts. To generate such assembly sequences selectively, a "Tournament Tree," which shows the structure of an assembly sequence, is formulated. Applying the method to assembly sequences of a water valve, good assembly sequences with the same structure as the Tournament Tree are identified. The structure of such a Tournament Tree tends to have fewer steps than the others. As a test, the structure is then applied for a drum cartridge with 38 parts. In all the assembly sequences generated from the contact-related figures, the best assembly sequence is generated by using the Tournament Tree.