Processing math: 100%
  • Title/Summary/Keyword: Optimal Operation

Search Result 2,845, Processing Time 0.031 seconds

Maximum Torque Operation of SRM by using a Self-tuning Control Method (SRM의 최대 토크 운전을 위한 자기동조 제어)

  • 서종윤;김광헌;장도현
    • The Transactions of the Korean Institute of Power Electronics
    • /
    • v.9 no.3
    • /
    • pp.240-245
    • /
    • 2004
  • This paper presents a Switched Reluctance Motor(SRM) drive using the self-tuning control method to achieve the maximum torque. SRM has the difficulty to research it by an analytic method and to control the speed End torque because of the high nonlinearity. So, in this paper, the self-tuning control method is applied to relevantly controlling turn-on/off angle to operate at the maximum torque. Also, the feedback signals to control the turn-on/off angle are the encoder pulse and the increment of phase current. At first, n adequate turn-off angle is searched by itself and then a turn-on angle is done. As the relationship between turn-on and him-off angle is mutual dependent, the turn-on/off angle is controlled by a real time self-tuning control method in order to maintain the maximum torque. The proposed self-tuning Algorithm is verified by experiments.

Optimal Capacitor Placement and Operation for Loss Minimzation and Improvement of Voltage Profile in Distribution System (배전계통의 손실감소 및 전압 보상을 위한 커패시터 최적 배치 및 운용)

  • 송현선
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.13 no.3
    • /
    • pp.48-55
    • /
    • 1999
  • Ths paper presents an optimization method which determines locations and size of capacitors simultaneously while minimizing power losses and improving voltage profile in radial distribution systems. Especially, the cost function associated with capacitor pla.cerrent is considered as step function due to banks of standard discrete capacities. Genetic algorithms(GA) are used to obtain efficiently the solution of the cost function associated with capacitors which is non-continuous and non-differentiable function. The strings in GA consist of the node nwnber index and size of capacitors to be installed. The length mutation operator, which is able to change the length of strings in each generation, is used. The proposed Jrethod which determines locations and size of capacitors simultaneously can reduce power losses and improve voltage proftle with capacitors of minimum size. Its efficiency is proved through the arolication in radial distribution systems.ystems.

  • PDF

Analysis of Distribution Properties on Astringent Persimmons(Diospyros Kaki L.) (떫은감의 유통특성 분석)

  • 노영균;장성호;박석희;변효숙;성전중
    • Food Science and Preservation
    • /
    • v.6 no.2
    • /
    • pp.184-187
    • /
    • 1999
  • This study was conducted to analyze distribution properties on astringent Persimmons(Diosyros Kaki L). We selected one hundred farms in Sangju and Cheongdo regions, which ale major region of astringent persimmon production in Kyungpook province, and surveyed the selling type and the optimal farm scale. As a result of economic analysis, between manufacturing and selling of dried persimmon and producing and selling of fresh persimmon, the former made the higher gross receipts, income and net income recorded by 187, 136 and 162 respectively, comparing with the latter 100. So, manufacturing and selling of dried persimmon from astringent persimmon is a way of raising operation outcome.

  • PDF

Circadian variation of IV PCA use in patients after orthognathic surgery - a retrospective comparative study

  • Park, Sookyung;Chi, Seong In;Seo, Kwang-Suk;Kim, Hyun Jeong
    • Journal of Dental Anesthesia and Pain Medicine
    • /
    • v.15 no.3
    • /
    • pp.141-146
    • /
    • 2015
  • Background: An understanding of the features of postoperative pain is essential for optimal analgesic dosing strategies. Using a visual analogue scale (VAS) score and patient controlled analgesia (PCA) infusion pattern analysis, an anesthesiologist can estimate when and how severely patients suffer from pain. Several reports have been published about circadian changes in the pain threshold. Postoperative pain was analyzed retrospectively in 250 patients who underwent orthognathic surgery. Methods: A total of 250 patients were allocated into two groups according to the time of recovery from anesthesia. Patients in the early group (group E) recovered from anesthesia before 06:00 p.m. Patients in the late group (group L) recovered from anesthesia after 06:00 p.m. All patients received intravenous patient controlled analgesia (IV PCA) at the end of the operation. The VAS score of pain intensity was measured. Self-administration of bolus analgesic from the IV PCA device was also analyzed according to actual time and elapsed time. Results: VAS scores showed no difference between the two groups except 36 hours after recovery from anesthesia. On POD1, there were two peaks for self-administration of bolus analgesics in group L and one peak in the morning for group E. Two peaks each in the morning and in the afternoon were shown in both groups on POD2. Conclusions: Diurnal variance in pain should be considered for effective dosing strategies.

A Spread Spectrum System Using Adaptive Modulation and Switched Diversity (적응변조와 안테나 교환 다이버시티 기술을 사용한 대역 확산 시스템)

  • Park, Jin-Kyu;Lim, Chang-Heon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.18 no.4 s.119
    • /
    • pp.440-447
    • /
    • 2007
  • The switched diversity, although its performance is a little inferior to the selection diversity, is widely used due to its advantage that only one RF circuit is required for its operation without respect to the number of antennas in use. In this paper, we propose an application of the antenna switched diversity to a spread spectrum system with adaptive modulation and derived the optimal antenna switching threshold to maximize the average transmission bit rate. We also compared the performances of the proposed system with those of the two cases using a single antenna and the selection diversity with two antennas in terms of the average number of bits per symbol(BPS), the probability of no transmission, and the average BER. The performance analysis shows that, if the number of paths in a multipath channel environment increases, the performance of the proposed scheme becomes closer to that of the selection diversity based system in terms of the average BPS. Furthermore, the proposed scheme produces as almost high the probability of no transmission as the selection diversity based system for the case of low average SNR, although the former yields a little higher probability of no transmission than the latter fer the case of high average SNR.

Biological Treatment of Dyeing Wastewater Using Jet Loop Reactor with Activated Carton Supports (활성탄 담체가 포함된 Jet-Loop Reactor를 이용한 종합염색폐수처리)

  • 조무환;박종탁;이길호;류원률
    • KSBB Journal
    • /
    • v.17 no.3
    • /
    • pp.241-246
    • /
    • 2002
  • Today, many problems of dye-processing wastewaters were raised due to industry of dyeing and textiles. It is difficult to treat them perfectly because they contain many poorly degradable matters, such as surfactants, ethylene glycol, polyvinyl alcohol, and so on. To improve the performances of conventional physicochemical treatment and activated sludge process, new systems of combining jet-loop reactor (JLR) with physicochemical treatment were developed. Volumetric oxygen transfer coefficient (kLa) of JLR was significantly larger than that of air-lift reactor. Also, for the effective treatment of dye-processing wastewater, JLR with active carbon supports (JLRAS) were investigated. Removal efficiency of BOD, CODMn, $COD_{Cr} and color were found as 99, 86, 84, 83%, respectively, when HRT was 8 hrs. And performance of JLRAS was rapidly restored after step change of CODMn loading late. The optimal coagulant and dosage of second physicochemical treatment after JLRAS were polyferric sulfate and 130 mg/L, respectively, when removal efficiencies of $COD_{Mn} and color were 85 and 73%, respectively. In conclusion, this system enables the reduction of operation cost, and the effective removal of many organics.

Continuous Production of Fructooligosaccharides from Sucrose by a Dual Immobilized Enzyme System of Fructosyltransferase and Glucose Isomerase (과당전이효소와 포도당 이성화 효소의 고정화 혼합효소계에 의한 설탕으로부터 프락토올리고당의 연속생산)

  • 윤종원;서근학송승구
    • KSBB Journal
    • /
    • v.10 no.1
    • /
    • pp.9-14
    • /
    • 1995
  • Continuous production of fructooligosaccharides from sucrose by a dual immobilized enzyme system of fructosyltransferase and glucose isomerase was studied in a column reactor. The optimal temperature and pH of the immobilized fructosyltransferase were 65C and 5.5, respectively. The activity of glucose isomerase was favorable as temperature and pH were increased within the ranges examined. However, both the immobilized enzymes were thermally unstable over 5C, suggesting that long-term operation of the dual immobilized enzyme column should be carried out below 50C. The optimum packing ratio of fructosyltransferase to glucose isomerase was found to be around 5/3. Under the optimized reaction conditions, the dual enzyme column was successfully operated for 40 days without any loss of initial enzyme activities, yielding 66% of fructooligosaccharides. Furthermore, the relative sweetness of fructooligosaccharides produced by a dual emzyme system was enhanced by 6% compared with that of fructosyltransferase alone.

  • PDF

Improvement of NIMBY Facilities Route Planning Considering Social Conflict (사회적 갈등을 고려한 비선호시설 노선 선정 개선 연구)

  • Choi, Younguk;Lee, Changjun;Han, Seung Heon
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.38 no.3
    • /
    • pp.487-496
    • /
    • 2018
  • In route selection process of NIMBY facilities, many conflicts occur due to route selection procedure and NIMBY syndrome. Especially, the social conflicts surrounding the site selection and operation are frequent enough to account for 70% of the total conflict cases, causing significant losses. To resolve the conflict in route selection, social conflicts are considered. Therefore, this study proposes an improved process of selecting route considering social conflicts in the power transmission line. First, the analysis of previous research trends and interviews with experts revealed the improved exclusion zone criteria, the factors and priorities of NIMBY facilities. After selecting the candidate routes, the optimal route is selected by using Fuzzy-TOPSIS. Hence, 83.3% of six experts have verified that this model minimizes conflicts and has sufficient applicability. The proposed model is expected to be used as a tool to minimize social conflict in the selection process of the power transmission line in the early stage of the project.

Development of a Object Oriented Framework for System Design Optimization (최적설계 지원 객체지향 프레임 웍 개발)

  • Chu, Min-Sic;Choi, Dong-Hoon;Lee, Se-Jung
    • Proceedings of the KSME Conference
    • /
    • 2001.06c
    • /
    • pp.369-375
    • /
    • 2001
  • For Optimization technology Was Developed in 1960, the Optimization Technology have grown into a full-featured, robust, highly rated and highly used. And Optimization techniques, having reached a degree of maturity over the past several years, are being used in a wide spectrum of industries, including aerospace, automotive, chemical, electrical, and manufacturing industries. With rapidly advancing computer technology, computers are becoming more powerful, and correspondingly, the size and the complexity of the problems being solved using Optimization techniques are also increasing. But Optimization techniques with analysis solver have many problems. For instance, the difficulties that a particular interface must be coded for each design problem and that the designer should be familiar with the optimization program as well as the analysis program. The purpose of this paper is Optimal Design Framework for Mechanical systems design. This Design Framework has two Optimizers, ADS (local optimizer) and RSM(Response Surface Method), and graphic user interfaces for formulation and optimum design problem and controlling the design process. Current Design Framework tested by two analysis solver, ADAMS and ANSYS. First this paper focused on the core Framework and their conception. In the second of the paper, I cover subjects such as Design Framework Operation. Next, The validity and effectiveness of Design Framework are shown by applying it to many practical design problems and obtaining satisfactory results. Finally, if you are an advanced Operator, you might want to use Response Surface Method, so that cover the result applied by RSM. here.

  • PDF

A Numerical Method & Experiments for the Aerodynamic Design of High Performance 2-Stage Axial Flow Fans (고성능 2단 축류송풍기의 공력설계를 위한 수치해석 및 실험에 관한 연구)

  • Cho, Jinsoo;Han, Cheolhui;Cho, Leesang
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.23 no.8
    • /
    • pp.1048-1062
    • /
    • 1999
  • A numerical method and experiments for the aerodynamic design of high performance two-stage axial flow fans was carried out. A vortex ring element method used for the aerodynamic analysis of the propellers was extended to the fan-duct system. Fan Performance and velocity profiles at the fan inlet and outlet are compared with experimental data for the validations of numerical method. Performance test was done based on KS B 6311(testing methods for turbo-fans and blowers). The velocity profile was obtained using a 5-hole pitot tube by the non-nulling method. The two stage axial flow fan configurations for the optimal operation conditions were set by using the experimental results for the single rotating axial flow fan and the single stage axial flow fan. The single rotating axial flow fan showed relatively low efficiency due to the swirl velocities behind rotor exit which produced pressure losses. In contrast, the single stage and the two-stage axial flow fans showed performance improvements due to the swirl velocity reduction by the stator. The peak efficiency of the two stage axial flow fan was improved by 21% and 6%, compared to the single rotating axial flow fan and the single stage axial flow fan, respectively.