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Sample records for current control strategies

  1. Current Control Strategy of Chain Circuit STATCOM

    Institute of Scientific and Technical Information of China (English)

    WANG Xuan; FU Jian; TENG Letian; SUN Lijing; ZHAO Ruibin; WU Shouyuan; DENG Zhanfeng

    2012-01-01

    In order to study the current control strategy based on the chain circuit static synchronous compensator (STATCOM) dynamic model and the design control system with good stability and tracking accuracy, this paper applies the chain circuit STATCOM small signal AC model, and proposes the following assumptions:

  2. Instantaneous Current Feedback Control Strategy on Buck Mode Inverter

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Control strategies for Buck mode inverter have important effect on static and dynamic characteristics, reliability, load capacity, and short-circuit resistance. Instantaneous current feedback control strategies include instantaneous inductor current feedback control and instantaneous capacitor current feedback control, both of which have essential difference. When the Buck mode inverter respectively adopts instantaneous inductor current and capacitor current feedback control strategies, characteristics of stability, output voltage and power, short circuit, nonlinear load and dynamic are fully investigated in this paper.

  3. Malaria vector control: current and future strategies

    NARCIS (Netherlands)

    Takken, W.; Knols, B.G.J.

    2009-01-01

    The recently announced call for malaria eradication represents a new page in the history of this disease. This has been triggered by remarkable reductions in malaria resulting from combined application of effective drugs and vector control. However, this strategy is threatened by development of inse

  4. Discrete Current Control Strategy of Permanent Magnet Synchronous Motors

    Directory of Open Access Journals (Sweden)

    Yan Dong

    2013-01-01

    Full Text Available A control strategy of permanent magnet synchronous motors (PMSMs, which is different from the traditional vector control (VC and direct torque control (DTC, is proposed. Firstly, the circular rotating magnetic field is analyzed on the simplified model and discredited into stepping magnetic field. The stepping magnetomotive force will drive the rotor to run as the stepping motor. Secondly, the stator current orientation is used to build the control model instead of rotor flux orientation. Then, the discrete current control strategy is set and adopted in positioning control. Three methods of the strategy are simulated in computer and tested on the experiment platform of PMSM. The control precision is also verified through the experiment.

  5. Steam generator degradation: Current mitigation strategies for controlling corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Millett, P. [Electric Power Research Institute, Palo Alto, CA (United States)

    1997-02-01

    Steam Generator degradation has caused substantial losses of power generation, resulted in large repair and maintenance costs, and contributed to significant personnel radiation exposures in Pressurized Water Reactors (PWRs) operating throughout the world. EPRI has just published the revised Steam Generator Reference Book, which reviews all of the major forms of SG degradation. This paper discusses the types of SG degradation that have been experienced with emphasis on the mitigation strategies that have been developed and implemented in the field. SG degradation is presented from a world wide perspective as all countries operating PWRs have been effected to one degree or another. The paper is written from a US. perspective where the utility industry is currently undergoing tremendous change as a result of deregulation of the electricity marketplace. Competitive pressures are causing utilities to strive to reduce Operations and Maintenance (O&M) and capital costs. SG corrosion is a major contributor to the O&M costs of PWR plants, and therefore US utilities are evaluating and implementing the most cost effective solutions to their corrosion problems. Mitigation strategies developed over the past few years reflect a trend towards plant specific solutions to SG corrosion problems. Since SG degradation is in most cases an economic problem and not a safety problem, utilities can focus their mitigation strategies on their unique financial situation. Accordingly, the focus of R&D has shifted from the development of more expensive, prescriptive solutions (e.g. reduced impurity limits) to corrosion problems to providing the utilities with a number of cost effective mitigation options (e.g. molar ratio control, boric acid treatment).

  6. Power electronic converters PWM strategies and current control techniques

    CERN Document Server

    Monmasson, Eric

    2013-01-01

    A voltage converter changes the voltage of an electrical power source and is usually combined with other components to create a power supply. This title is devoted to the control of static converters, which deals with pulse-width modulation (PWM) techniques, and also discusses methods for current control. Various application cases are treated. The book is ideal for professionals in power engineering, power electronics, and electric drives industries, as well as practicing engineers, university professors, postdoctoral fellows, and graduate students.

  7. Improved control strategy for PI-R current of DFIG considering voltage and current harmonics compensation

    Science.gov (United States)

    Song, S. Y.; Liu, Q. H.; Zhao, Y. N.; Liu, S. Y.

    2016-08-01

    With the rapid development of wind power generation, the related research of wind power control and integration issues has attracted much attention, and the focus of the research are shifting away from the ideal power grid environment to the actual power grid environment. As the main stream wind turbine generator, a doubly-fed induction generator (DFIG) is connected to the power grid directly by its stator, so it is particularly sensitive to the power grid. This paper studies the improvement of DFIG control technology in the power grid harmonic environment. Based on the DFIG dynamic model considering the power grid harmonic environment, this paper introduces the shortcomings of the common control strategy of DFIG, and puts forward the enhanced method. The decoupling control of the system is realized by compensating the coupling between the rotor harmonic voltage and harmonic current, improving the control performance. In addition, the simulation experiments on PSCAD/EMTDC are carried out to verify the correctness and effectiveness of the improved scheme.

  8. Research on transient hysteresis current control strategy of DC-DC converter

    Science.gov (United States)

    Zhang, Ting; Wang, Zu-liang; Zhao, Yu-kai

    2017-01-01

    In order to improve the dynamic performance of DC-DC converter, transient hysteresis current control strategy is proposed which is based on parallel computing and combinational logic. By making a comparison between the real-time inductor current and the threshold inductor current, the switch is controlled more accurately. Under the Matlab/Simulink environment, the process of the Buck-Boost converter was simulated. The simulation results show that the transient hysteresis current control strategy can effectively overcome the disadvantages when load changes or input voltage disturbance occurs, it posses high load regulation and short dynamic response time, and it verifies the feasibility of the proposed strategy.

  9. Balanced Current Control Strategy for Current Source Rectifier Stage of Indirect Matrix Converter under Unbalanced Grid Voltage Conditions

    Directory of Open Access Journals (Sweden)

    Yeongsu Bak

    2016-12-01

    Full Text Available This paper proposes a balanced current control strategy for the current source rectifier (CSR stage of an indirect matrix converter (IMC under unbalanced grid voltage conditions. If the three-phase grid connected to the voltage source inverter (VSI of the IMC has unbalanced voltage conditions, it affects the currents of the CSR stage and VSI stage, and the currents are distorted. Above all, the distorted currents of the CSR stage cause instability in the overall system, which can affect the life span of the system. Therefore, in this paper, a control strategy for balanced currents in the CSR stage is proposed. To achieve balanced currents in the CSR stage, the VSI stage should receive DC power without ripple components from the CSR stage. This is implemented by controlling the currents in the VSI stage. Therefore, the proposed control strategy decouples the positive and negative phase-sequence components existing in the unbalanced voltages and currents of the VSI stage. Using the proposed control strategy under unbalanced grid voltage conditions, the stability and life span of the overall system can be improved. The effectiveness of the proposed control strategy is verified by simulation and experimental results.

  10. A Coordinate Control Strategy for Circulating Current Suppression in Multiparalleled Three-Phase Inverters

    DEFF Research Database (Denmark)

    Zhang, Xueguang; Wang, Tianyi; Wang, Xiongfei

    2017-01-01

    This paper addresses the zero-sequence circulating current control in the multiparalleled three-phase voltage-source inverters. The model of the zero-sequence circulating current in the N-paralleled (N ≥ 3) inverters is derived. It is shown that the circulating current is not only susceptible...... to the mismatches of circuit parameters, but it is also influenced by the interactions of circulating current controllers used by other paralleled inverters. To eliminate these adverse effects on the circulating current control loop, a coordinate control strategy for the N-paralleled inverter is proposed based...

  11. Analysis and design of over-current limit control strategies applied in aeronautical power supplies

    Institute of Scientific and Technical Information of China (English)

    WANG Lin-bing; HE Xiang-ning

    2007-01-01

    Some Over-Current Limit Control strategies are analyzed and designed to meet the demands of high reliability and rapid dynamic response in the aeronautical power supply applications. The control schemes are both effective in DC-DC converters and DC-AC converters. Controller models are set up, and the over-current limit operation principles of analogy and digital control are analyzed too. An 800VA aeronautical power supply has been constructed to verify the performance of the proposed control strategy in various cases such as the sudden load change and the constant load. The analysis and experiments confirm the advantages of the proposed over-current limit strategies as follows: simple,effective and reliable.

  12. A NOVEL CONTROL STRATEGY FOR SINUSIODAL WAVE INVERTER WITH PI REGULATORS AND CAPACITOR CURRENT FEEDBACK

    Institute of Scientific and Technical Information of China (English)

    姜桂宾; 裴云庆; 王兆安

    2003-01-01

    Objective For the inverters used in UPS, it is important to maintain the pure sinusoidal AC output voltage waveform over all loading conditions and transients. Methods A novel sinusoidal output voltage control strategy is pregented in this paper. The output voltage is controlled by introducing filtering eapacitor current feedback. Two simple PI regulators are used for the current and voltage control loops. Results With the new control strategy, the inverter achieves very low output voltage distortion, good output voltage regulation and strong perturbation rejection, fast dynamic response, and good performance under nonlinear loads. The THD under capacitance rectifying load is better than 0.2%, the output voltage regulation within 0 to full load is less than 0.1%. The resting time under load transient is within 200μs. Conclusion The merits of the new control strategy include rapid response and good steady state stiffness.

  13. An inductance Fourier decomposition-based current-hysteresis control strategy for switched reluctance motors

    Science.gov (United States)

    Hua, Wei; Qi, Ji; Jia, Meng

    2017-05-01

    Switched reluctance machines (SRMs) have attracted extensive attentions due to the inherent advantages, including simple and robust structure, low cost, excellent fault-tolerance and wide speed range, etc. However, one of the bottlenecks limiting the SRMs for further applications is its unfavorable torque ripple, and consequently noise and vibration due to the unique doubly-salient structure and pulse-current-based power supply method. In this paper, an inductance Fourier decomposition-based current-hysteresis-control (IFD-CHC) strategy is proposed to reduce torque ripple of SRMs. After obtaining a nonlinear inductance-current-position model based Fourier decomposition, reference currents can be calculated by reference torque and the derived inductance model. Both the simulations and experimental results confirm the effectiveness of the proposed strategy.

  14. Nutrition and Physical Activity Strategies for Cancer Prevention in Current National Comprehensive Cancer Control Program Plans.

    Science.gov (United States)

    Puckett, Mary; Neri, Antonio; Underwood, J Michael; Stewart, Sherri L

    2016-10-01

    Obesity, diet and physical inactivity are risk factors for some cancers. Grantees of the National Comprehensive Cancer Control Program (NCCCP) in US states, tribes, and territories develop plans to coordinate funding and activities for cancer prevention and control. Including information and goals related to nutrition and physical activity (NPA) is a key opportunity for primary cancer prevention, but it is currently unclear to what extent NCCCP plans address these issues. We reviewed 69 NCCCP plans and searched for terms related to NPA. Plans were coded as (1) knowledge of NPA and cancer link; (2) goals to improve NPA behaviors; and (3) strategies to increase healthy NPA activities, environments, or systems changes. NPA content was consistently included in all cancer plans examined across all years. Only 4 (6 %) outlined only the relationship between NPA and cancer without goals or strategies. Fifty-nine plans (89 %) contained goals or strategies related to NPA, with 53 (82 %) including both. However, numbers of goals, strategies, and detail provided varied widely. All programs recognized the importance of NPA in cancer prevention. Most plans included NPA goals and strategies. Increasing the presence of NPA strategies that can be modified or adapted appropriately locally could help with more widespread implementation and measurement of NPA interventions.

  15. A New Type Hi-Speed BLDC Control System Base on Indirect Current Control Strategy

    Science.gov (United States)

    Wang, D. P.; Wang, Y. C.; Zhang, F. G.; Jin, S.

    2017-05-01

    High speed BLDC has the characteristic as larger air gap smaller armature inductance, traditional PWM modulation will produce a great number of high frequency current harmonics which led problem like large torque ripple and serious motor heat. In the meantime traditional PWM modulation use the diode rectifier which cause harmonic pollution in electric power net. To solve the problem above, proposes a new motor controller topology. Using the IGBT device to replace the diode on frequency converter rectifier side, apply the power factor correction technology, reduce the pollution on the grid. Using busbar current modulation on the inverter, driving bridge-arm use 3-phase 6-state open as driving Mode, realize the control on a 10000r/min,10kw BLDC. The results of Simulation on matlab show the topological structure as proposed can effectively improve the network side power factor and reduce the motor armature winding harmonic and motor torque ripple.

  16. A cooperative control strategy of resistance spot welding process by combining the constant current control with the DRC method

    Institute of Scientific and Technical Information of China (English)

    Li Guizhong; Wang Changzheng; Kong Meng; Guo Caiguang

    2009-01-01

    The modeling control method based on the dynamic resistance characteristics of good nuggets, that is the DRC method, is an improvement on the dynamic resistance threshold method for the quality control of resistance spot welding. But there is still a control blind area in the initial four cycles. For this reason, the quality of every weld nugget could not be fully ensured. Thus a new fuzzy cooperative control method is put forward. It uses a multi-information time-control mechanism by combining the constant current control technology with the DRC method in a relay way. This whole-process control strategy has led to a good control effect and produced the dual-identicul results in the weld nugget quality and the welding time.

  17. A Harmonic Current Suppression Control Strategy for Droop-Controlled Inverter Connected to the Distorted Grid

    DEFF Research Database (Denmark)

    Wei, Feng; Sun, Kai; Guan, Yajuan;

    2015-01-01

    being adopted for abstracting the fundamental components of grid voltage. The injected fundamental power is controlled through droop controller, and a hybrid voltage controller of GF-VCI with PI and R regulators in rotary frame is adopted for improving of the tracking capability of the grid harmonic...

  18. Modelling of a Vector-current Controlled UPFC and Comprehensive Comparison with the Power-angle Control Strategy

    Science.gov (United States)

    Ren, Bixing; Du, Wenjuan; Cai, Hui; Wang, Haifeng; Wang, Xiangfeng; Zhang, Jianpeng

    2017-05-01

    This paper establishes the non-linear dynamic mathematical model of the vector-current controlled unified power flow controller (UPFC) and the linearized model of the UPFC is derived in detail afterwards for the analysis of dynamic performance stability. Then, the paper carries out deep investigations on the comparison and analysis for the above two control strategies applied to the UPFC in the aspects of dynamic interaction and auxiliary damping effect. The relative gain array (RGA) method is used to assess the dynamic interactions among the multiple control functions of the UPFC, and damping torque analysis (DTA) method is used to compare the damping performance of the UPFC auxiliary damping controller. The results of quantitative comparison by RGA and DTA analysis show that the vector-current controlled UPFC exhibits better decoupling characteristic among multiple control loops, while the power-angle controlled UPFC exhibits better auxiliary damping performance. Conclusions are further validated by the non-linear simulation results via a two-area four-machine system.

  19. Current status and strategies for the control of viral hepatitis A in Korea.

    Science.gov (United States)

    Yoon, Eileen L; Sinn, Dong Hyun; Lee, Hyun Woong; Kim, Ji Hoon

    2017-09-01

    Hepatitis A virus is one of the most frequent causes of foodborne infection, which is closely associated with sanitary conditions and hygienic practices. The clinical spectrum of acute hepatitis A is wide, ranging from mild case without any noticeable symptoms to severe case with acute liver failure leading to mortality. The severity and outcome are highly correlated with age at infection. In developing countries, most people are infected in early childhood without significant symptom. Ironically, in area where sanitary condition has improved rapidly, adults who do not have immunity for viral hepatitis A (VH-A) in early childhood is accumulating. Adults without immunity are exposed to risks of symptomatic disease and large outbreaks in society. In Korea, where hygiene has improved rapidly, acute hepatitis A is a significant health burden that needs to be managed with nationwide health policy. The incidence of symptomatic VH-A has increased since 2000 and peaked in 2009. Korea has designated hepatitis A as a group 1 nationally notifiable infectious disease in 2001. Since 2001, mandatory surveillance system has been established to detect every single case of acute hepatitis A. Universal, nationwide vaccination program for newborns was introduced in 2015. In this review, we will present the current epidemiologic status of viral hepatitis A, and evaluate the effectiveness of the current nationwide strategies for the control of viral hepatitis A in Korea. Furthermore, we presented some action proposals that can help eliminate viral hepatitis A, which is a significant health burden in Korea.

  20. Current Status of Air Toxics Management and Its Strategies for Controlling Emissions in Taiwan

    Directory of Open Access Journals (Sweden)

    Wen-Tien Tsai

    2016-04-01

    Full Text Available Since the 1970s, hazardous air pollutants (HAPs, so-called air toxics, have been of great concern because they can cause serious human health effects and have adverse effects on the environment. More noticeably, some of them are known to be human carcinogens. The objective of this paper is to investigate the regulatory systems and human health effects of air toxics which have been designated by the Taiwan government under the Air Pollution Control Act. These toxic air pollutants include acutely toxic gas (i.e., ammonia, chlorine, fluorides, hydrochloric acid, hydrogen cyanide, hydrogen sulfide, nitric acid, phosphoric acid and sulfuric acid, gas containing heavy metals, and carcinogenic chemicals (including formaldehyde, vinyl chloride, asbestos and matter containing asbestos, dioxins and furans, volatile organic compounds, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls. In line with international concern about the carcinogenic risk and environmental persistence of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs and heavy metals in recent years, the current status in monitoring and reducing the emissions of PCDDs/PCDFs from stationary sources was analyzed as a case study in the present study. Furthermore, the control strategies for reducing emissions of air toxics from stationary sources in Taiwan were also addressed.

  1. A ZVS PWM control strategy with balanced capacitor current for half-bridge three-level DC/DC converter

    DEFF Research Database (Denmark)

    Liu, Dong; Deng, Fujin; Chen, Zhe

    2017-01-01

    The capacitor current would be imbalanced under the conventional control strategy in the half-bridge three-level (HBTL) DC/DC converter due to the effect of the output inductance of the power supply and the input line inductance, which would affect the converter's reliability. This paper proposes...... a pulse-wide modulation (PWM) strategy composed of two operation modes for the HBTL DC/DC converter, which can realize the zero-voltage switching (ZVS) for the efficiency improvement. In addition, a capacitor current balancing control is proposed by alternating the two operation modes of the proposed ZVS...... PWM strategy, which can eliminate the current imbalance among the two input capacitors. Therefore, the proposed control strategy can improve the converter's performance and reliability in: 1) reducing the switching losses and noises of the power switches; 2) balancing the thermal stresses...

  2. Effects of Direct Torque Control Switching Strategies on Common Voltage and Bearing Current

    Directory of Open Access Journals (Sweden)

    Mohammad Taghi Sadeghzadeh

    2012-04-01

    Full Text Available Bearing current sininduction motorsare considered a sone of the most damaging factors. Induced shaft voltage through the parasitic capacitors cause this type of current. Inthispaper,given the increasing importance of direct torque control of induction motorin industry, various switching tables are assessed in order to ensure the lowest common voltage while maintaining the performance characteristics of the drive. Finally best switching table based on the minimum CMV, less torque rippleand better quality out put reference tracking is proposed.

  3. An Optimal PR Control Strategy with Load Current Observer for a Three-Phase Voltage Source Inverter

    Directory of Open Access Journals (Sweden)

    Xiaobo Dou

    2015-07-01

    Full Text Available Inverter voltage control is an important task in the operation of a DC/AC microgrid system. To improve the inverter voltage control dynamics, traditional approaches attempt to measure and feedforward the load current, which, however, needs remote measurement with communications in a microgrid system with distributed loads. In this paper, a load current observer (LCO based control strategy, which does not need remote measurement, is proposed for sinusoidal signals tracking control of a three-phase inverter of the microgrid. With LCO, the load current is estimated precisely, acting as the feedforward of the dual-loop control, which can effectively enlarge the stability margin of the control system and improve the dynamic response to load disturbance. Furthermore, multiple PR regulators are applied in this strategy conducted in a stationary  frame to suppress the transient fluctuations and the total harmonic distortion (THD of the output voltage and achieve faster transient performance compared with traditional dual-loop control in a rotating dq0 frame under instantaneous change of various types of load (i.e., balanced load, unbalanced load, and nonlinear load. The parameters of multiple PR regulators are analyzed and selected through the root locus method and the stability of the whole control system is evaluated and analyzed. Finally, the validity of the proposed approach is verified through simulations and a three-phase prototype test system with a TMS320F28335 DSP.

  4. Fault Characteristics and Control Strategies of Multiterminal High Voltage Direct Current Transmission Based on Modular Multilevel Converter

    Directory of Open Access Journals (Sweden)

    Fei Chang

    2015-01-01

    Full Text Available The modular multilevel converter (MMC is an emerging voltage source converter topology suitable for multiterminal high voltage direct current transmission based on modular multilevel converter (MMC-MTDC. This paper presents fault characteristics of MMC-MTDC including submodule fault, DC line fault, and fault ride-through of wind farm integration. Meanwhile, the corresponding protection strategies are proposed. The correctness and effectiveness of the control strategies are verified by establishing a three-terminal MMC-MTDC system under the PSCAD/EMTDC electromagnetic transient simulation environment.

  5. A review of current strategy for rabies prevention and control in the developing world

    Directory of Open Access Journals (Sweden)

    Suneela Garg

    2017-03-01

    Full Text Available The control of Rabies, a zoonotic viral disease is a major public challenge in several developing countries. Current approaches for rabies control are overwhelmingly directed towards provision of effective post exposure prophylaxis (PEP to animal bite victims. The enormous costs involved in rabies prophylaxis is an important factor precluding its universal application in all animal bite victims especially in those residing in resource constrained settings. The intradermal route of administration has been shown to be cost effective except in peripheral regions with fewer animal bite cases. Nevertheless, rabies control program with their expected emphasis on human rabies prophylaxis have neglected canine vaccination. The feasibility of canine rabies vaccination depends primarily upon allocation of resources through political commitment and effective public private partnerships. However, in large parts of the world including India formal dog ownership constitutes a small minority of the overall canine population while state funded canine vaccination drives often fail to impress policy makers who struggle to maintain budgets for adequate coverage of rabies PEP for animal bite victims. The key to rabies control may therefore rest upon a one health approach with development of newer vaccine technology which is cost effective for vaccination in both, man and animal.

  6. An Embedded Voltage Harmonic Compensation Strategy for Current Controlled DG Interfacing Converters

    DEFF Research Database (Denmark)

    Zhao, Xin; Meng, Lexuan; Guerrero, Josep M.

    2016-01-01

    Harmonics have been considered as one of the major issues in future power grids. With the increasing demand in advanced control functions, power electronic converter interfaced Distributed Generators (DGs) are expected to perform harmonic compensation when necessary. It has been demonstrated in a...... voltage detection; 3) compared with conventional voltage detection based method, it offers better performance because of direct harmonic voltage regulation. Experimental results are presented to demonstrate the effectiveness of the method....... in a number of studies that DG converters operating in Voltage-Controlled Mode (VCM) can be easily configured to realize voltage harmonic suppression utilizing naturally embedded voltage control loop. While for DG converters operating in Current-Controlled Mode (CCM), such function was rarely studied....... Considering that CCM is commonly used in renewable energy based generators and energy storage systems, it has certain significance to achieve the same function with CCM operated converters. Aiming at such objective, this paper proposes a voltage detection based embedded Harmonic Compensator (HC) for CCM...

  7. Epidemiology of dengue in Nepal: History of incidence, current prevalence and strategies for future control.

    Science.gov (United States)

    Subedi, Dinesh; Taylor-Robinson, Andrew W

    2016-03-01

    Dengue is now established as one of the most important arboviral infections. As the epidemic continues unabated globally, this Aedes mosquito-transmitted pathogen is considered a major re-emerging tropical disease and significant public health concern. Four well-established distinct serotypes of dengue virus, with a fifth one recently proposed, are responsible for causing a spectrum of clinical symptoms in humans ranging from mild fever to severe haemorrhagic manifestations. Indigenous cases of dengue were first recognised in Nepal, a Himalayan country bordered by India and China, just a decade ago in a cluster of tropical and subtropical areas. Subsequently, the range of infection has extended all over the country and now comprises not only low lying regions, but also hilly locations including the capital city Kathmandu. The two major epidemics to date, in 2010 and 2013, have demonstrated the capacity of infection outbreaks to be explosive and challenging to currently available disease control measures. There is a pressing need to undertake effective vector surveillance studies supported by provision of well-equipped diagnostic virology laboratories. However, sincere efforts are being made to map the nationwide prevalence and understand the epidemiology of dengue infection. Yet, the precise burden of dengue in Nepal remains unknown, since most reports are confined to economically affluent areas and do not account for regions of relative social deprivation in which disease is more likely to occur. This review presents a current overview of dengue in Nepal and discusses future prospects for control of this debilitating disease in the country.

  8. Control Strategies for Islanded Microgrid using Enhanced Hierarchical Control Structure with Multiple Current-Loop Damping Schemes

    DEFF Research Database (Denmark)

    Han, Yang; Shen, Pan; Zhao, Xin

    2017-01-01

    In this paper, the modeling, controller design, and stability analysis of the islanded microgrid (MG) using enhanced hierarchical control structure with multiple current loop damping schemes is proposed. The islanded MG is consisted of the parallel-connected voltage source inverters using LCL...

  9. Current Status of HIV/AIDS in Cameroon: How Effective are Control Strategies?

    Directory of Open Access Journals (Sweden)

    Dora Mbanya

    2008-12-01

    Full Text Available Nearly three decades after its discovery, HIV infection remains the number one killer disease in Sub-Saharan Africa where up to 67% of the world’s 33 million infected people live. In Cameroon, based on a Demographic Health Survey carried out in 2004, the national HIV prevalence is estimated at 5.5% with women and youths being predominantly infected. Orphans and vulnerable children (OVC from the HIV and AIDS pandemic have increased steadily over the years; hospital occupancy is estimated at about 30%, hence stretching the health system; co-infections like HIV/tuberculosis have been reported to reach 40-50% of infected cases and 95% of teachers are said not to be productive on several counts. Thus, the impact is multi-sectorial. Furthermore, the HIV epidemic in Cameroon is peculiar because of the wide HIV-1 genetic diversity of HIV-1 Group M observed with several subtypes reported (A, B, C, D, F, G, H, J, K, predominantly subtype A. There are also circulating recombinant forms, mainly CRF02_AG. In addition, HIV-1 Groups O and N have all been noted in Cameroon. These findings have great implications not only for HIV diagnosis, but also for responsiveness to therapy as well as for vaccine development. In 1986, the initial response of the Cameroon government to the increasing trends in the HIV/AIDS infection was to create a National AIDS Control Committee to coordinate a national AIDS programme. By 2000, the first National Strategic Plan was drawn for 2000-2005. The second National Strategic Plan for 2006-2010 is currently being implemented and covers various axes. Some results obtained show that there has been significantly positive outcomes noted in the various arms of intervention by the Cameroon government.

  10. Current status of HIV/AIDS in Cameroon: how effective are control strategies?

    Science.gov (United States)

    Mbanya, Dora; Sama, Martyn; Tchounwou, Paul

    2008-12-01

    Nearly three decades after its discovery, HIV infection remains the number one killer disease in Sub- Saharan Africa where up to 67% of the world's 33 million infected people live. In Cameroon, based on a Demographic Health Survey carried out in 2004, the national HIV prevalence is estimated at 5.5% with women and youths being predominantly infected. Orphans and vulnerable children (OVC) from the HIV and AIDS pandemic have increased steadily over the years; hospital occupancy is estimated at about 30%, hence stretching the health system; co-infections like HIV/tuberculosis have been reported to reach 40-50% of infected cases and 95% of teachers are said not to be productive on several counts. Thus, the impact is multi-sectorial. Furthermore, the HIV epidemic in Cameroon is peculiar because of the wide HIV-1 genetic diversity of HIV-1 Group M observed with several subtypes reported (A, B, C, D, F, G, H, J, K), predominantly subtype A. There are also circulating recombinant forms, mainly CRF02_AG. In addition, HIV-1 Groups O and N have all been noted in Cameroon. These findings have great implications not only for HIV diagnosis, but also for responsiveness to therapy as well as for vaccine development. In 1986, the initial response of the Cameroon government to the increasing trends in the HIV/AIDS infection was to create a National AIDS Control Committee to coordinate a national AIDS programme. By 2000, the first National Strategic Plan was drawn for 2000-2005. The second National Strategic Plan for 2006-2010 is currently being implemented and covers various axes. Some results obtained show that there has been significantly positive outcomes noted in the various arms of intervention by the Cameroon government.

  11. [Whooping cough in Spain. Current epidemiology, prevention and control strategies. Recommendations by the Pertussis Working Group].

    Science.gov (United States)

    Campins, Magda; Moreno-Pérez, David; Gil-de Miguel, Angel; González-Romo, Fernando; Moraga-Llop, Fernando A; Arístegui-Fernández, Javier; Goncé-Mellgren, Anna; Bayas, José M; Salleras-Sanmartí, Lluís

    2013-04-01

    A large increase of pertussis incidence has been observed in recent years in countries with high vaccination coverage. Outbreaks of pertussis are increasingly being reported. The age presentation has a bipolar distribution: infants younger 6months that have not initiated or completed a vaccination schedule, and adolescents and adults, due to the lost of natural or vaccine immunity over time. These epidemiological changes justify the need to adopt new vaccination strategies in order to protect young infants and to reduce pertussis incidence in all age groups. Adolescents and adults immunization must be a priority. In the first group, strategy is easy to implement, and with a very low additional cost (to replace dT vaccine by dTap one). Adult vaccination may be more difficult to implement; dT vaccine decennial booster should be replaced by dTap. The immunization of household contacts of newborn infants (cocooning) is the strategy that has a most important impact on infant pertussis. Recently, pregnant women vaccination (after 20weeks of gestation) has been recommended in some countries as the most effective way to protect the newborn.

  12. Sustainability of vector control strategies in the Gran Chaco Region: current challenges and possible approaches

    Directory of Open Access Journals (Sweden)

    Ricardo E Gürtler

    2009-07-01

    Full Text Available Sustainability has become a focal point of the international agenda. At the heart of its range of distribution in the Gran Chaco Region, the elimination of Triatoma infestans has failed, even in areas subject to intensive professional vector control efforts. Chagas disease control programs traditionally have been composed of two divorced entities: a vector control program in charge of routine field operations (bug detection and insecticide spraying and a disease control program in charge of screening blood donors, diagnosis, etiologic treatment and providing medical care to chronic patients. The challenge of sustainable suppression of bug infestation and Trypanosoma cruzi transmission can be met through integrated disease management, in which vector control is combined with active case detection and treatment to increase impact, cost-effectiveness and public acceptance in resource-limited settings. Multi-stakeholder involvement may add sustainability and resilience to the surveillance system. Chagas vector control and disease management must remain a regional effort within the frame of sustainable development rather than being viewed exclusively as a matter of health pertinent to the health sector. Sustained and continuous coordination between governments, agencies, control programs, academia and the affected communities is critical.

  13. Current situation and challenges in implementing Malaria control strategies in Pakistan.

    Science.gov (United States)

    Ghanchi, N K; Shakoor, S; Thaver, A M; Khan, M S; Janjua, A; Beg, M A

    2016-08-01

    Malaria transmission is unstable in Pakistan with the highest number of cases reported during the monsoon season. Despite its high incidence, malaria is still a poorly resourced, poorly funded and an uncontrolled disease especially in far-flung areas. Pakistan's National Malaria Control Program (NMCP), although operational since its inception in 1947, has suffered due to the unstable political, socioeconomic and financial situation prevalent in the country. In Pakistan, more than 300 000 cases of malaria are reported every year with 68% of the cases caused by Plasmodium vivax. It is estimated that about 70-80% of the population accesses the private sector for treatment. As the private sector does not routinely report data to the government, the actual malaria burden could be 4-5 times higher than reported. P. vivax now accounts for more than 85% of all cases requiring hospital admission compared to 54% in 2000. In this review, we have described the saga of poor control of malaria in Pakistan over several years in context of restructuring of the Malaria Control Program, challenges to improvement, and way forward.

  14. Mixed methods research in tobacco control with youth and young adults: A methodological review of current strategies.

    Science.gov (United States)

    Fryer, Craig S; Seaman, Elizabeth L; Clark, Rachael S; Plano Clark, Vicki L

    2017-01-01

    Tobacco use among young people is a complex and serious global dilemma that demands innovative and diverse research approaches. The purpose of this methodological review was to examine the current use of mixed methods research in tobacco control with youth and young adult populations and to develop practical recommendations for tobacco control researchers interested in this methodology. Using PubMed, we searched five peer-reviewed journals that publish tobacco control empirical literature for the use of mixed methods research to study young populations, age 12-25 years. Our team analyzed the features of each article in terms of tobacco control topic, population, youth engagement strategies, and several essential elements of mixed methods research. We identified 23 mixed methods studies published by authors from five different countries reported between 2004 and 2015. These 23 articles examined various topics that included tobacco use behavior, tobacco marketing and branding, and cessation among youth and young adults. The most common mixed methods approach was variations of the concurrent design in which the qualitative and quantitative strands were administered at the same time and given equal priority. This review documented several innovative applications of mixed methods research as well as challenges in the reporting of the complex research designs. The use of mixed methods research in tobacco control has great potential for advancing the understanding of complex behavioral and sociocultural issues for all groups, especially youth and young adults.

  15. Mixed methods research in tobacco control with youth and young adults: A methodological review of current strategies

    Science.gov (United States)

    Seaman, Elizabeth L.; Clark, Rachael S.; Plano Clark, Vicki L.

    2017-01-01

    Introduction Tobacco use among young people is a complex and serious global dilemma that demands innovative and diverse research approaches. The purpose of this methodological review was to examine the current use of mixed methods research in tobacco control with youth and young adult populations and to develop practical recommendations for tobacco control researchers interested in this methodology. Methods Using PubMed, we searched five peer-reviewed journals that publish tobacco control empirical literature for the use of mixed methods research to study young populations, age 12–25 years. Our team analyzed the features of each article in terms of tobacco control topic, population, youth engagement strategies, and several essential elements of mixed methods research. Results We identified 23 mixed methods studies published by authors from five different countries reported between 2004 and 2015. These 23 articles examined various topics that included tobacco use behavior, tobacco marketing and branding, and cessation among youth and young adults. The most common mixed methods approach was variations of the concurrent design in which the qualitative and quantitative strands were administered at the same time and given equal priority. This review documented several innovative applications of mixed methods research as well as challenges in the reporting of the complex research designs. Conclusions The use of mixed methods research in tobacco control has great potential for advancing the understanding of complex behavioral and sociocultural issues for all groups, especially youth and young adults. PMID:28841689

  16. Zero-Voltage Switching PWM Strategy Based Capacitor Current-Balancing Control for Half-Bridge Three-Level DC/DC Converter

    DEFF Research Database (Denmark)

    Liu, Dong; Deng, Fujin; Zhang, Qi

    2017-01-01

    The current imbalance among the two input capacitors is one of the important issues of the half-bridge threelevel (HBTL) DC/DC converter, which would affect system performance and reliability. In this paper, a zero-voltage switching (ZVS) pulse-wide modulation (PWM) strategy including two operation...... modes is proposed. Based on the proposed ZVS PWM strategy, a capacitor current-balancing control is proposed for the HBTL DC/DC converter, where the currents on the two input capacitors can be kept balanced by alternating the two operation modes of the proposed ZVS PWM strategy. Therefore, the proposed...... control strategy can improve the performance and reliability of the converter in the aspect of balancing the thermal stresses and lifetimes among the two input capacitors. Finally, simulation and experimental studies are conducted and results verify the proposed control strategy....

  17. Adaptive Fuzzy PID Based Control Strategy For 3Phase 4Wire Shunt Active Filter To Mitigate Current Harmonics Of Grid Interconnection Of Renewable Energy Based Distribution System

    Directory of Open Access Journals (Sweden)

    Kaleemullah

    2016-06-01

    Full Text Available This paper presents a new control strategy for controlling the shunt active power filter to compensate reactive power and to reduce the unwanted harmonics in the grid current. Shunt active filter act as a current source which is connected in parallel with a non-linear load and controlled to produce the required compensating current. The proposed control strategy is based on the fuzzy PID controller which is used for determining the reference compensating currents of the three-phase shunt active power filters. Simulations are carried out using MATLAB/SIMULINK to verify the performance of the proposed controller. The output shows the controller has fast dynamic response high accuracy of tracking DC voltage reference and robust to load parameters variations.

  18. A Simple Autonomous Current-Sharing Control Strategy for Fast Dynamic Response of Parallel Inverters in Islanded Microgrids

    DEFF Research Database (Denmark)

    Guan, Yajuan; Vasquez, Juan Carlos; Guerrero, Josep M.

    2014-01-01

    This paper proposed a novel control strategy based on a virtual resistance and a phase locked loop for parallel three-phase inverters. The proposed controller can overcome the drawbacks of the conventional droop control such as slow transient response, complex design, and limited stability margin...

  19. Input-Parallel Output-Parallel (IPOP) Three-Level (TL) DC/DC Converters with Interleaving Control Strategy for Minimizing and Balancing Capacitor Ripple Currents

    DEFF Research Database (Denmark)

    Liu, Dong; Deng, Fujin; Gong, Zheng

    2017-01-01

    In this paper, the input-parallel output-parallel (IPOP) three-level (TL) DC/DC converters associated with the interleaving control strategy are proposed for minimizing and balancing the capacitor ripple currents. The proposed converters consist of two four-switch half-bridge three-level (HBTL) DC....../DC converters featuring with simple and compact circuit structures, which can reduce the current stresses of the components and increase the power rating of the converter. The combination of the proposed IPOP TL circuit structure and the interleaving control strategy can greatly reduce the ripple currents...... on the two input capacitor not only by doubling the frequencies of these ripple currents as the universal benefit of utilizing the interleaving control strategy but also by counteracting part of these ripple currents due to the operation principle of the proposed IPOP TL circuit structure. More importantly...

  20. The epidemiology of dengue infection: Harnessing past experience and current knowledge to support implementation of future control strategies

    Directory of Open Access Journals (Sweden)

    Narayan Gyawali

    2016-01-01

    Full Text Available Dengue is the most important mosquito-borne viral infection of humans. Although outbreaks of disease which are now recognized as clinically consistent with dengue have been reported for centuries, it was not until half a century ago that laboratory identification of dengue viruses as the etiological agent of febrile illness was achieved. This debilitating and sometimes fatal disease is widely distributed in >125 countries in tropical and subtropical zones of the world. Asia, South America and the Pacific Islands are hyper-epidemic regions while currently there is less prevalence in Europe, North America and Australia. The estimated global incidence ranges between 200 and 400 million clinical cases per year. While some areas of past epidemics are now considered to be under control, recent decades have witnessed an epidemic rise in dengue worldwide. Major factors facilitating expansion include climate change and increase in urbanization and international travel. Concurrently, the non-availability of an efficacious antiviral drug or vaccine and a lack of effective vector control strategies collectively make dengue a serious public health concern. Thus, it is of paramount importance to analyze the history of the spread of infection and to gain a deeper understanding of patterns of transmission in order to anticipate epidemiological trends more accurately, thereby enabling better preparedness for future outbreaks.

  1. Abc-frame complex-coefficient filter and controller based current harmonic elimination strategy for three-phase grid connected inverter

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Guerrero, Josep M.

    2016-01-01

    inverter. Different from the traditional method, our proposal utilizes the unique abc-frame complex-coefficient filter and controller to achieve the balanced, sinusoidal grid current. The main feature of the proposed method is simple and easy to implement without any frame transformation. The theoretical...... analysis and experimental test are presented. The experimental results verify the effectiveness of the proposed control strategy....

  2. Inrush Current Control Circuit

    Science.gov (United States)

    Cole, Steven W. (Inventor)

    2002-01-01

    An inrush current control circuit having an input terminal connected to a DC power supply and an output terminal connected to a load capacitor limits the inrush current that charges up the load capacitor during power up of a system. When the DC power supply applies a DC voltage to the input terminal, the inrush current control circuit produces a voltage ramp at the load capacitor instead of an abrupt DC voltage. The voltage ramp results in a constant low level current to charge up the load capacitor, greatly reducing the current drain on the DC power supply.

  3. An improved synchronous reference frame current control strategy for a photovoltaic grid-connected inverter under unbalanced and nonlinear load conditions

    DEFF Research Database (Denmark)

    Naderipour, Amirreza; Asuhaimi Mohd Zin, Abdullah; Bin Habibuddin, Mohd Hafiz

    2017-01-01

    In recent years, renewable energy sources have been considered the most encouraging resources for grid and off-grid power generation. This paper presents an improved current control strategy for a three-phase photovoltaic grid-connected inverter (GCI) under unbalanced and nonlinear load conditions...

  4. Development of Digital Hysteresis Current Control with PLL Loop Gain Compensation Strategy for PWM Inverters with Constant Switching Frequency

    Directory of Open Access Journals (Sweden)

    N. Belhaouchet

    2008-03-01

    Full Text Available Hysteresis current control is one of the simplest techniques used to control the magnitude and phase angle of motor current for motor drives systems. However, this technique presents several disadvantages such as operation at variable switching frequency which can reveal problems of filtering, interference between the phases in the case of the three-phase systems with insulated neutral connection or delta connection, and irregularity of the modulation pulses which especially causes an acoustic noise on the level of the machine for the high power drive. In this paper, a new technique is proposed for a variable-hysteresis-band controller based on dead beat control applied to three phase voltage source PWM inverters feeding AC motors. Its main aim is firstly ensure a constant switching frequency and secondly the synchronization of modulation pulses using the phase-locked-loop with loop gain compensation in order to ensure a better stability. The behavior of the proposed technique is verified by simulation.

  5. An improved synchronous reference frame current control strategy for a photovoltaic grid-connected inverter under unbalanced and nonlinear load conditions

    Science.gov (United States)

    Naderipour, Amirreza; Asuhaimi Mohd Zin, Abdullah; Bin Habibuddin, Mohd Hafiz; Miveh, Mohammad Reza; Guerrero, Josep M.

    2017-01-01

    In recent years, renewable energy sources have been considered the most encouraging resources for grid and off-grid power generation. This paper presents an improved current control strategy for a three-phase photovoltaic grid-connected inverter (GCI) under unbalanced and nonlinear load conditions. It is challenging to suppress the harmonic content in the output current below a pre-set value in the GCI. It is also difficult to compensate for unbalanced loads even when the grid is under disruption due to total harmonic distortion (THD) and unbalanced loads. The primary advantage and objective of this method is to effectively compensate for the harmonic current content of the grid current and microgrid without the use of any compensation devices, such as active and passive filters. This method leads to a very low THD in both the GCI currents and the current exchanged with the grid. The control approach is designed to control the active and reactive power and harmonic current compensation, and it also corrects the system unbalance. The proposed control method features the synchronous reference frame (SRF) method. Simulation results are presented to demonstrate the effective performance of the proposed method. PMID:28192436

  6. An improved synchronous reference frame current control strategy for a photovoltaic grid-connected inverter under unbalanced and nonlinear load conditions.

    Science.gov (United States)

    Naderipour, Amirreza; Asuhaimi Mohd Zin, Abdullah; Bin Habibuddin, Mohd Hafiz; Miveh, Mohammad Reza; Guerrero, Josep M

    2017-01-01

    In recent years, renewable energy sources have been considered the most encouraging resources for grid and off-grid power generation. This paper presents an improved current control strategy for a three-phase photovoltaic grid-connected inverter (GCI) under unbalanced and nonlinear load conditions. It is challenging to suppress the harmonic content in the output current below a pre-set value in the GCI. It is also difficult to compensate for unbalanced loads even when the grid is under disruption due to total harmonic distortion (THD) and unbalanced loads. The primary advantage and objective of this method is to effectively compensate for the harmonic current content of the grid current and microgrid without the use of any compensation devices, such as active and passive filters. This method leads to a very low THD in both the GCI currents and the current exchanged with the grid. The control approach is designed to control the active and reactive power and harmonic current compensation, and it also corrects the system unbalance. The proposed control method features the synchronous reference frame (SRF) method. Simulation results are presented to demonstrate the effective performance of the proposed method.

  7. Current state of concussion prevention strategies: a systematic review and meta-analysis of prospective, controlled studies.

    Science.gov (United States)

    Schneider, Daniel K; Grandhi, Ravi K; Bansal, Purnima; Kuntz, George E; Webster, Kate E; Logan, Kelsey; Barber Foss, Kim D; Myer, Gregory D

    2017-10-01

    The aim of the current review was to systematically identify, evaluate and synthesise trials that examine concussion prevention via equipment, educational programmes and training programmes. PubMed and EBSCO host (CINAHL, MEDLINE, SPORTDiscus). The electronic databases PubMed and EBSCO were searched using the phrases: concussion prevention equipment, concussion prevention training and concussion prevention education. Included studies utilised a prospective study design to evaluate the preventative effect of: (1) equipment, (2) training or (3) educational programmes on the incidence of concussions in comparison to a control group. Demographic data and intervention methods were recorded. Intervention and control group concussion rates and superficial head injury rates were extracted and combined using random-effects relative risk meta-analysis. 14 studies evaluated interventions of novel protective equipment. One prospective investigation evaluated an educational programme. The relative risk of concussion for participants enrolled in the interventional arms of trials was not significantly different from that in standard practice arms (RR=0.78, 95% CI 0.55 to 1.11, χ(2)=1.8, p=0.17; I(2)=85.3%, 95% CI 71.5% to 90.8%). The relative risk of concussion for participants wearing protective equipment (ie, headgear, full face shields) relative to their counterparts wearing standard or no equipment, calculated from seven available reports, showed no effect of intervention (RR=0.82, 95% CI 0.56 to 1.20, χ(2)=1.06, p=0.30; I(2)=86.7%, 95% CI 73.3% to 91.8%). The relative risk of superficial head injury for participants wearing protective equipment relative to their counterparts, calculated from three reports, showed a significant risk reduction (RR=0.41, 95% CI 0.31 to 0.56, χ(2)=34.13, p<0.0001; I(2)=53.1%, 95% CI 0% to 85.2%). Prospective controlled studies indicate that certain protective equipment may prevent superficial head injury, but these items are suboptimal for

  8. Avian influenza control strategies

    Science.gov (United States)

    Control strategies for avian influenza in poultry vary depending on whether the goal is prevention, management, or eradication. Components used in control programs include: 1) education which includes communication, public awareness, and behavioral change, 2) changes to production and marketing sys...

  9. DFIG Harmonic Current Controlling with the Grid Low Harmonic Voltage

    Directory of Open Access Journals (Sweden)

    Huan Wang

    2014-01-01

    Full Text Available This study presents a vector control strategy based on stator harmonic current closed-loop, it adds individually the control loop about of each stator harmonic current to restrain the stator harmonic current, in order to meet the THD criteria. The control strategy of restraining the harmonic current presents the design of the stator harmonic current restrains the current controller. It influences the rotor voltage of the stator harmonic current restraining strategies.

  10. Controlled current inductors

    Science.gov (United States)

    Thaler, S.

    1970-01-01

    Magnetic permeability and shape of special core inserts are varied to produce desired changes in saturation characteristics of current dependent inductor, thus improving its inductance-to-current properties. Materials and saturation levels of the core pieces are selected to permit a wide variety of relationships between inductance and current.

  11. Amoeba-related health risk in drinking water systems: could monitoring of amoebae be a complementary approach to current quality control strategies?

    Science.gov (United States)

    Codony, Francesc; Pérez, Leonardo Martín; Adrados, Bárbara; Agustí, Gemma; Fittipaldi, Mariana; Morató, Jordi

    2012-01-01

    Culture-based methods for fecal indicator microorganisms are the standard protocol to assess potential health risk from drinking water systems. However, these traditional fecal indicators are inappropriate surrogates for disinfection-resistant fecal pathogens and the indigenous pathogens that grow in drinking water systems. There is now a range of molecular-based methods, such as quantitative PCR, which allow detection of a variety of pathogens and alternative indicators. Hence, in addition to targeting total Escherichia coli (i.e., dead and alive) for the detection of fecal pollution, various amoebae may be suitable to indicate the potential presence of pathogenic amoeba-resisting microorganisms, such as Legionellae. Therefore, monitoring amoeba levels by quantitative PCR could be a useful tool for directly and indirectly evaluating health risk and could also be a complementary approach to current microbial quality control strategies for drinking water systems.

  12. Current Strategies in Cardiovascular Biomaterial Functionalization

    Directory of Open Access Journals (Sweden)

    Karla Lehle

    2010-01-01

    Full Text Available Prevention of the coagulation cascade and platelet activation is the foremost demand for biomaterials in contact with blood. In this review we describe the underlying mechanisms of these processes and offer the current state of antithrombotic strategies. We give an overview of methods to prevent protein and platelet adhesion, as well as techniques to immobilize biochemically active molecules on biomaterial surfaces. Finally, recent strategies in biofunctionalization by endothelial cell seeding as well as their possible clinical applications are discussed.

  13. Tax Strategy Control

    DEFF Research Database (Denmark)

    Rossing, Christian Plesner

    2013-01-01

    This paper examines how a functional tax strategy impacts the management control system (MCS) in a multinational enterprise (MNE) facing transfer pricing tax risks. Based on case study findings it is argued that the MCS in a multinational setting is contingent upon the MNE's response to its tax...... environment. Moreover, the paper extends existing contingency-based theory on MCS by illustrating the role of inter-organisational network collaboration across MNE transfer pricing tax experts. This collaboration, caused by a widely dispersed tax knowledge base, fuels the formal interactive control system...... and reduces tax uncertainty. The paper adopts an interdisciplinary approach for explaining findings, using contingency-based theory and network theory at the inter-organisational level....

  14. A Novel Sensorless Control Strategy for Brushless Direct Current Motor Based on the Estimation of Line Back Electro-Motive Force

    Directory of Open Access Journals (Sweden)

    Chengde Tong

    2017-09-01

    Full Text Available In this paper, a novel sensorless control strategy based on the estimation of line back electro-motive force (BEMF is proposed. According to the phase relationship between the ideal commutation points of the brushless direct current motor (BLDCM and the zero-crossing points (ZCPs of the line BEMF, the calculation formula of line BEMF is simplified properly and the commutation rule for different positions of the rotor is presented. The estimation error of line BEMF caused by the freewheeling current of silent phase is analyzed, and the solution is given. With the phase shift of the low-pass filter considered, a compensation method using “60°-α” and “120°-α” is studied in this paper to eliminate the error. Finally, the simulation and experimental results show that the rotor-position-detection error is reduced effectively and the motor driven by the accurate commutation signal can work well at low and high speed.

  15. Control strategy minimizing the converter-alternating current motor losses: application to electric traction; Strategies de commande minimisant les pertes d'un ensemble convertisseur - machine alternative: application a la traction electrique

    Energy Technology Data Exchange (ETDEWEB)

    Bastiani, Ph.

    2001-02-01

    Improving the efficiency of the converter-alternating current motor system is a major task in electric traction. Global energy optimisation implies a specific approach at system scale. To reach this goal, we have chosen an algebraic method using sub-system models. To start with, a synchronous machine Park model is developed to take account magnetic saturation and iron losses. Then, an averaged model of the voltage inverter is used in order to obtain a simplified model of the losses to be implemented in our optimisation method. This is how the global model is built including losses in the synchronous machine along with the losses of the power converter. Experimental results are there to validate our approach. This study proposes a method based on algebraic formulation of the general laws to control torque. Algorithms take into account magnetic circuits saturation and power losses in both the machine and its converter. Here again, experimental results validate the algorithm on several test benches. Achieved efficiency improvement is important compared to existing usual control strategies. The proposed method can be generalised to other machine-converter systems. As a matter of fact we have extended our study to the induction machine. As a complement ti this study we have looked at the effects natural limitations of voltages and currents in the torque-speed plane. Therefore algebraic formulation of the torque-speed plane and optimisation strategies are proposed including those constraints. (author)

  16. A randomised controlled trial evaluating IGF1 titration in contrast to current GH dosing strategies in children born small for gestational age

    DEFF Research Database (Denmark)

    Jensen, Rikke Beck; Thankamony, Ajay; O'Connell, Susan M

    2014-01-01

    BACKGROUND: Short children born small for gestational age (SGA) are treated with a GH dose based on body size, but treatment may lead to high levels of IGF1. The objective was to evaluate IGF1 titration of GH dose in contrast to current dosing strategies. METHODS: In the North European Small-for-...

  17. Current conservation strategies for European crayfish

    Directory of Open Access Journals (Sweden)

    Kozák P.

    2011-05-01

    Full Text Available A round table discussion involving 25 researchers from 11 European countries was organized during the congress “European Crayfish: food, flagships and ecosystem services” (held in Poitiers, France, 26–29th October 2010 to consider current activities dealing with management of indigenous crayfish species (ICS with special regards to their culture, restocking and conservation strategy. In the following opinion paper, we attempt to summarize best practice of current conservation strategy as well as advantages and disadvantages of applied tools and approaches for listed species or species complexes. The development of conceptual models for the protection of ICS in Europe seems to be necessary; however, currently recommended approaches of conservation strategy of ICS differ according to countries and species. The different approaches to conservation of Astacus astacus and species in the genus Austropotamobius, such as genetic diversity, captive breeding, origin and characteristics of stocking material and establishment, as well as long-term objectives of sanctuary or “ark” sites, were highlighted during the round table discussion.

  18. Strategies for Industrial Multivariable Control

    DEFF Research Database (Denmark)

    Hangstrup, M.

    Multivariable control strategies well-suited for industrial applications are suggested. The strategies combine the practical advantages of conventional SISO control schemes and -technology with the potential of multivariable controllers. Special emphasis is put on parameter-varying systems whose...... dynamics and gains strongly depend upon one or more physical parameters characterizing the operating point. This class covers many industrial systems such as airplanes, ships, robots and process control systems. Power plant boilers are representatives for process control systems in general. The dynamics...

  19. Current data and strategy in glioblastoma multiforme

    Science.gov (United States)

    Dinca, EB

    2009-01-01

    Glioblastoma multiforme (GBM) or astrocytoma grade Ⅳ on WHO classification is the most aggressive and the most frequent of all primary brain tumors. Glioblastoma is multiforme , resistant to therapeutic interventions illustrating the heterogeneity exhibited by this tumor in its every aspect, including clinical presentation, pathology, genetic signature. Current data and treatment strategy in GBM are presented focusing on basic science data and key clinical aspects like surgery, including personal experience; adjuvant modalities: radiotherapy, chemotherapy, but also for experimental approaches. Therapeutic attitude in recurrent GBM is also widely discussed. PMID:20108752

  20. Disturbance observer based current controller for vector controlled IM drives

    DEFF Research Database (Denmark)

    Teodorescu, Remus; Dal, Mehmet

    2008-01-01

    In order to increase the accuracy of the current control loop, usually, well known parameter compensation and/or cross decoupling techniques are employed for advanced ac drives. In this paper, instead of using these techniques an observer-based current controller is proposed for vector controlled...... coupling effects and increase robustness against parameters change without requiring any other compensation strategies. The experimental implementation results are provided to demonstrate validity and performance of the proposed control scheme.......In order to increase the accuracy of the current control loop, usually, well known parameter compensation and/or cross decoupling techniques are employed for advanced ac drives. In this paper, instead of using these techniques an observer-based current controller is proposed for vector controlled...

  1. National Drug Control Strategy, 2011

    Science.gov (United States)

    Office of National Drug Control Policy, 2011

    2011-01-01

    In May of 2010, President Obama released the Administration's inaugural "National Drug Control Strategy". Based on the premise that drug use and its consequences pose a threat not just to public safety, but also to public health, the 2010 "Strategy" represented the first comprehensive rebalancing of Federal drug control policy in the nearly 40…

  2. 新疆麻疹流行现状和控制策略%Analysis of current epidemiological situation of measles and strategies for controlling measles in Xinjiang

    Institute of Scientific and Technical Information of China (English)

    袁玉莲; 戴述齐

    2001-01-01

    Objective To analyze the current epidemiological situation of measles and to put forward strategies for controlling measles in Xinjiang. Methods A descriptive epidemiology was performed to survey incidence of measles in Xinjiang from 1953~1999. Results  The highest incidence rate of 1 155.14 per 100 000 was reported in 1964. Since 1 965, the measles incidence had dramatically decreased with using measles vaccine in Xinjiang, particularly the action of launching EPI program since 1984. The l owest incidence rate of 7.85 per 100 000 was achieved in 1990. From 1990~1 999 cases mostly concentrated on preschool and school children. Seasonal distri b ution of measles was in April and May. Conclusions It is urgent to improve efficacy of measles vaccine, to establish measles epidemiological an d laboratory surveillance system, and to strengthen immunization for measles and controlling of the outbreak.%目的 分析新疆麻疹流行的现状并提出控制策略 。方法 用描述流行病学方法对1953~1999年新疆麻疹发病情况分析。 结果 1964年报告发病率为1 155.14/10万。 自1965年开始使用麻疹疫苗(MV)以来,特别是1984年开展计划免疫活动以后,我区麻疹 的发病率大幅度下降,流行强度明显降低,到1990年发病率已降至历史最低水平7.85/10万 。1990~1999年麻疹主要在学龄前儿童和小学生中发病,冬春高发,其中4、5月份发病数 最多。结论 应建立监测系统,开展麻疹强化免疫活动,控制麻疹爆发。

  3. Molecular imaging: current status and emerging strategies

    Energy Technology Data Exchange (ETDEWEB)

    Pysz, M.A. [Department of Radiology, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, CA (United States); Gambhir, S.S. [Department of Radiology, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, CA (United States); Departments of Bioengineering and Materials Science and Engineering, Stanford University, Stanford, CA (United States); Willmann, J.K., E-mail: willmann@stanford.ed [Department of Radiology, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, CA (United States)

    2010-07-15

    In vivo molecular imaging has a great potential to impact medicine by detecting diseases in early stages (screening), identifying extent of disease, selecting disease- and patient-specific treatment (personalized medicine), applying a directed or targeted therapy, and measuring molecular-specific effects of treatment. Current clinical molecular imaging approaches primarily use positron-emission tomography (PET) or single photon-emission computed tomography (SPECT)-based techniques. In ongoing preclinical research, novel molecular targets of different diseases are identified and, sophisticated and multifunctional contrast agents for imaging these molecular targets are developed along with new technologies and instrumentation for multi-modality molecular imaging. Contrast-enhanced molecular ultrasound (US) with molecularly-targeted contrast microbubbles is explored as a clinically translatable molecular imaging strategy for screening, diagnosing, and monitoring diseases at the molecular level. Optical imaging with fluorescent molecular probes and US imaging with molecularly-targeted microbubbles are attractive strategies as they provide real-time imaging, are relatively inexpensive, produce images with high spatial resolution, and do not involve exposure to ionizing irradiation. Raman spectroscopy/microscopy has emerged as a molecular optical imaging strategy for ultrasensitive detection of multiple biomolecules/biochemicals with both in vivo and ex vivo versatility. Photoacoustic imaging is a hybrid of optical and US techniques involving optically-excitable molecularly-targeted contrast agents and quantitative detection of resulting oscillatory contrast agent movement with US. Current preclinical findings and advances in instrumentation, such as endoscopes and microcatheters, suggest that these molecular imaging methods have numerous potential clinical applications and will be translated into clinical use in the near future.

  4. 三相电压型PWM整流器无电流传感器控制策略研究%Study on the Sensorless Current Control Strategy of Three- Phase Voltage- Source PWM Rectifier

    Institute of Scientific and Technical Information of China (English)

    毛鸿; 吴兆麟; 王毅; 刘树林

    2001-01-01

    三相电压型PWM整流器有间接电流控制和直接电流控制两种方式,两种控制方式各有优点。根据三相电压型PWM整流器的高频动态数学模型,提出了基于开关函数检测的无电流传感器控制策略。该控制策略兼有间接电流控制结构简单,成本低和直接电流控制动态响应速度快、限流容易、控制精度高等优点。实验结果验证了控制策略的可行性。%There are two basic control schemes for three-phase voltage-source PWM rectifier: the direct current control and indirect current control. The direct current control scheme achieves better dynamic and steady state performance, but its control cost is much higher than the indirect current control. Based on the dynamic high frequency mathematical model of three-phase voltage-source PWM rectifier, a novel sensorless current control strategy is presented for the first time, which is implemented by estimating the variables of the three-phase input current via other variables. The control strategy has super characters such as simple structure, low cost, good dynamic and steady state performance and ability to limit the input currents. A simple hardware implementation is proposed and the good experimental results are reported to confirm the quality of the presented strategy.

  5. Inductor Current Sampled Feedback Control of Chaos in Current-Mode Boost Converter

    Institute of Scientific and Technical Information of China (English)

    Bo-Cheng Bao; Jian-Ping Xu; Yan Liang

    2008-01-01

    A chaos control strategy for chaotic current-mode boost converter is presented by using inductor current sampled feedback control technique. The quantitative analysis of control mechanism is performed by establishing a discrete alterative map of the controlled system. The stability criterion, feedback gain, and corresponding critical duty ratio are obtained from the eigenvalue of the map. The simulation results verify the theoretical analysis results of the control strategy.

  6. Capacitor Current Feedback-Based Active Resonance Damping Strategies for Digitally-Controlled Inductive-Capacitive-Inductive-Filtered Grid-Connected Inverters

    Directory of Open Access Journals (Sweden)

    Iman Lorzadeh

    2016-08-01

    Full Text Available Inductive-capacitive-inductive (LCL-type line filters are widely used in grid-connected voltage source inverters (VSIs, since they can provide substantially improved attenuation of switching harmonics in currents injected into the grid with lower cost, weight and power losses than their L-type counterparts. However, the inclusion of third order LCL network complicates the current control design regarding the system stability issues because of an inherent resonance peak which appears in the open-loop transfer function of the inverter control system near the control stability boundary. To avoid passive (resistive resonance damping solutions, due to their additional power losses, active damping (AD techniques are often applied with proper control algorithms in order to damp the LCL filter resonance and stabilize the system. Among these techniques, the capacitor current feedback (CCF AD has attracted considerable attention due to its effective damping performance and simple implementation. This paper thus presents a state-of-the-art review of resonance and stability characteristics of CCF-based AD approaches for a digitally-controlled LCL filter-based grid-connected inverter taking into account the effect of computation and pulse width modulation (PWM delays along with a detailed analysis on proper design and implementation.

  7. Magnetoelectric control of spin currents

    Science.gov (United States)

    Gómez, J. E.; Vargas, J. M.; Avilés-Félix, L.; Butera, A.

    2016-06-01

    The ability to control the spin current injection has been explored on a hybrid magnetoelectric system consisting of a (011)-cut ferroelectric lead magnesium niobate-lead titanate (PMNT) single crystal, a ferromagnetic FePt alloy, and a metallic Pt. With this PMNT/FePt/Pt structure we have been able to control the magnetic field position or the microwave excitation frequency at which the spin pumping phenomenon between FePt and Pt occurs. We demonstrate that the magnetoelectric heterostructure operating in the L-T (longitudinal magnetized-transverse polarized) mode couples the PMNT crystal to the magnetostrictive FePt/Pt bilayer, displaying a strong magnetoelectric coefficient of ˜140 Oe cm kV-1. Our results show that this mechanism can be effectively exploited as a tunable spin current intensity emitter and open the possibility to create an oscillating or a bistable switch to effectively manipulate spin currents.

  8. The effect of applied control strategy on the current-voltage correlation of a solid oxide fuel cell stack during dynamic operation

    Directory of Open Access Journals (Sweden)

    Szmyd Janusz S.

    2014-09-01

    Full Text Available This paper discusses the transient characteristics of the planar type SOFC cell stack, of which the standard output is 300 W. The transient response of the voltage to the manipulation of an electric current was investigated. The effects of the response and of the operating condition determined by the operating temperature of the stack were studied by mapping a current-voltage (I-V correlation. The current-based fuel control (CBFC was adopted for keeping the fuel utilization factor at constant while the value of the electric current was ramped at the constant rate. The present experimental study shows that the transient characteristics of the cell voltage are determined by primarily the operating temperature caused by the manipulation of the current. Particularly, the slope of the I-V curve and the overshoot found on the voltage was remarkably influenced by the operating temperature. The different values of the fuel utilization factor influence the height of the settled voltages. The CBFC has significance in determining the slope of the I-V characteristic, but the different values ofthe fuel utilization factor does not affect the slope as the operating temperature does. The CBFC essentially does not alter the amplitude of the overshoot on the voltage response, since this is dominated by the operating temperature and its change is caused by manipulating the current.

  9. Current guidelines in defining therapeutic strategies.

    Science.gov (United States)

    Ferrajoli, Alessandra; Keating, Michael J

    2004-08-01

    The past three decades have brought major changes in the approach toward chronic lymphocytic leukemia (CLL). This disease was considered a simple form of leukemia for which the only goal of treatment was control of the leukocytosis and of the symptoms related to disease expansion. Many biologic discoveries have increased our understanding of the disease process. New prognostic markers have been identified and are being incorporated into clinical practice. Now, CLL is considered a complex and challenging leukemia for which multiple treatment options are emerging, from chemotherapy to monoclonal antibodies, from vaccines to immunomodulatory strategies. The evaluation of treatment results also has been revolutionized: clones carrying genetic aberrations are monitored, and patients who have had a response are assessed for the presence of minimal residual disease.

  10. Predictive Current Control Strategy Based on ADALINE for Active Power Filter%基于ADALINE的有源电力滤波器预测电流控制策略

    Institute of Scientific and Technical Information of China (English)

    章兢; 于晶荣

    2009-01-01

    为有效补偿有源电力滤波器(APF)的控制延时, 提出一种基于自适应线性神经元(ADALINE)的APF预测电流控制策略.该策略通过ADALINE预测下一控制周期的参考电流, 根据两相静止坐标系下APF系统模型确定参考电压, 利用空间矢量脉宽调制(SVPWM)方法, 使APF输出电流快速、准确地跟踪参考电流.仿真与APF样机上的实际运行结果表明, 和采用传统无预测算法的SVPWM方法相比, 采用本文提出的预测电流控制策略, APF的稳态补偿精度和动态跟踪性能均明显提高.%In order to compensate control delay of active power filter (APF), a predictive current control strategy based on ADAptive LInear NEuron (ADALINE) for three-phase APF is proposed. Reference compensation current for next control cycle is calculated by current predictive algorithm based on ADALINE, and reference voltage is determined according to APF mathematical model in two-phase static coordinate system. The output current of APF can track to reference current quickly and exactly by space vector pulse width modulation (SVPWM) method. Simulation and experimental results on APF prototype demonstrate that, compared with APF of SVPWM control without predictive algorithm, APF with predictive current control strategy based on ADALINE has higher steady state compensation accuracy and better dynamic performance.

  11. [Discussion of HIV control and prevention strategies].

    Science.gov (United States)

    Lyu, P

    2016-10-06

    Expansion of HIV testing and ART treatment are core strategies for achieving the ambitious global goal of ending the HIV epidemic by the end of 2030, and achieving the "90-90-90" target by 2020. In China, great progress in HIV control and prevention has been made; however, there is room to enhance the effectiveness of HIV-related strategies. In addition, some implemented strategies have not achieved their expected output. To confront the challenge of sexual transmission of HIV, which is the main route of transmission in China, more targeted HIV prevention strategies that lead to their expected outcomes are essential. It is important to strengthen existing strategies that have been proved effective. However, it is also critical to create innovative strategies, and there are five approaches to achieve this. First, a holistic perspective should be adopted, to better understand the current situation and problems. This means intervention strategies should give serious consideration of how to meet the sociocultural needs of target populations rather than merely carry out behavioral interventions. Second, community-based HIV prevention settings should have more important roles in providing HIV-related health care services. Moreover, to improve the effectiveness of these strategies, a problem-led working style should be integrated into HIV prevention measures overall. Third, thoroughly analyzing characteristics of the current HIV epidemic using more evidence-based considerations must be undertaken, to better control HIV sexual transmission. Fourth, continued improvement of AIDS prevention and control mechanisms is needed, to ensure their sustainable development. Last, it is necessary to involve more NGOs in HIV prevention work by strengthening their management and working capacities to provide HIV-related services. Also needed is further improvement in both technical and management capacities, so as to build a stable basis for effective response.

  12. 伤寒的现状分析及预防控制%Analysis on current situation and strategies of prevention and control for typhoid fever

    Institute of Scientific and Technical Information of China (English)

    何莓; 王惟信; 华羚; 张宏; 许震生

    2012-01-01

    伤寒是由伤寒杆菌引起的严重急性传染病,主要发生在亚洲、非洲和拉丁美洲地区,严重威胁人类健康.伤寒杆菌经粪一口途径传播,人类是唯一的传染源,因此伤寒与环境和食品卫生状况密切相关.近年来多重耐药菌株的出现,使伤寒的抗生素治疗日益复杂,因此严格遵守饮食和饮水卫生及接种伤寒疫苗仍是预防控制该病的主要手段.本文就伤寒的疾病特征、流行分布、多重耐药情况、预防控制及疫苗应用等情况进行了综述.%Typhoid fever is an acute, life-threatening infectious illness caused by salmonella typhosa, which occurs mainly in Asia, Africa and Latin America. Transmission of typhoid fever occurs via the fecal-oral route. Humans are the only source. Personal hygiene and appropriate sanitation are thought to be closely related to typhoid infection. In recent years, the emergence of multidrug resistance in S. typhi has complicated the treatment, food and water precautions and vaccination against typhoid fever remain the essential preventive strategies. The article reviews the feature of typhoid fever, epidemic distribution, multidrug resistance, prevention and control and vaccine application, etc.

  13. Start-stop Control Strategy for UPFC with Fault Current Limiting%限流式统一潮流控制器的启停控制策略

    Institute of Scientific and Technical Information of China (English)

    沈忱; 江道灼; 吕文韬; 王玉芬

    2013-01-01

    限流式统一潮流控制器(UPFC)可以有效避免串联变换器因系统短路电流冲击而损毁。针对限流式UPFC已有功率控制策略的不足,建立了含限流式 UPFC 的系统模型,提出了基于线路电流控制的功率控制策略。分析了限流式UPFC的启停过程,给出了完整的启停控制方案。启动阶段接入限流电阻以防止直流电容充电电流过大而导致过电压和过电流损坏。停机时通过并联变换器释放直流电容的一部分能量从而降低放电电阻的设计要求。PSCAD/EMTDC软件的建模与仿真结果证明了基于线路电流控制的限流式UPFC功率控制策略具有良好的动态和稳态性能,同时也验证了启停控制方案的合理性和有效性。%The unified power flow controller with fault current limiting (UPFC-FCL) can effectively protect series converter from being damaged by short circuit current.In view of the inadequacy of existing power control strategies for UPFC-FCL,a power system model with UPFC-FCL is developed,and a power control strategy based on line current control is proposed.The start-stop process of UPFC-FCL is analyzed,then a complete start-stop control scheme is proposed.In the start process,the charging rate of DC capacitor is limited by current-limiting resistance,which prevents overvoltage or overcurrent of the equipment.In the stop process,the design requirements of discharge resistance can be reduced as the energy of DC capacitance is partly released through the shunt converter.PSCAD/EMTDC simulation results demonstrate that the UPFC-FCL power control strategy based on line current control has good dynamic and steady performance,and the start-stop control scheme is rational and effective.

  14. SPARTINA CONTROL STRATEGY OF CHINA

    Institute of Scientific and Technical Information of China (English)

    TAN Fang-Lin

    2007-01-01

    Spartina is a kind of very important and invasive grass. In its native range, it is very important for erosion control, fish, wildlife, and estuary reclamation. Therefore, it was introduced to many countries. Since 1963, it was introduced to China. Up to now, it was intentionally or accidentally planted nearly all estuaries in the east coast of China and the area was estimated over 0.1 × 106 hm2. As other introduced plants, Spartina grows very vigorously in China,and this caused many environmental and economical problems. So, it is an emergency to develop a Spartina control strategy of China. In the paper, the history of Spartina introduction in China was reviewed, and several methods which were probably feasible for China to control Spartina were introduced, including physical/mechanical (such as mowing, digging, and dredging), chemical, and biological methods. Before taking any measurments to control Spartina, 2 things should be done. The first was to develop a plan and make an inventory; the second was to select a feasible method according to local climatic, economic, social, and ecological conditions. It was suggested that it would be very important to assess the possible effect of control methods on the environment in order to prevent from causing other environmental problems.KEY WORDS :Spartina; control method; control strategy; environmental assessment

  15. Stability analysis of direct current control in current source rectifier

    DEFF Research Database (Denmark)

    Lu, Dapeng; Wang, Xiongfei; Blaabjerg, Frede

    2017-01-01

    Current source rectifier with high switching frequency has a great potential for improving the power efficiency and power density in ac-dc power conversion. This paper analyzes the stability of direct current control based on the time delay effect. Small signal model including dynamic behaviors...... of dc link is developed to identify the control plants of grid ac current control and dc current control. Analysis on the poles and zeros under dq frame is carried out. Base on this model, it turns out that the phase lag caused by the time delay can stabilized the grid ac current control while reduces...... the stable region for dc current control. Simulation and experimental results are presented to validate the theoretical analysis....

  16. A New One-cycle Control Strategy of Capacitor Current on Grid-connected Inverter%一种并网逆变器的电容电流单周期控制技术

    Institute of Scientific and Technical Information of China (English)

    吴静; 刘晓东; 方炜; 刘宿城

    2016-01-01

    On the basis of double-loops control structure of capacitive current being inner loop and net current being outer loop, a new current control strategy is proposed combining one-cycle digital control strategy with QPR controller. One-cycle controller is applied in the system inner loop in αβ stationary reference frame, and then, the duty function of one-cycle control bipolar algorithm of capacitor current is obtained to improve the anti-jamming performance of the system and to simplify the tuning process. The quasi proportional resonant(QPR) controller of the outer loop is adopted to control the grid-connected currents directly without complicated coordinates transform. Finally, Experimental results indicate that the proposed control scheme allows three-phase gird-tied inverter to meet the grid-connected demands, and the system has a good dynamic performance.%在LCL型并网逆变器传统双环结构(电容电流内环、并网电流外环)基础上,提出一种结合数字单周期控制和准比例谐振控制的新型电流控制策略。在αβ静止坐标系下,将单周期控制应用于系统内环,推导出了电容电流单周期数字控制占空比函数,提高了系统抗干扰能力并简化调节过程;外环采用准比例谐振控制器直接控制并网电流,省去了复杂的坐标变换,计算简单。最后,实验结果表明所提出控制策略能够实现逆变器有效并网,且动态性能良好。

  17. Control strategy of shortcut nitrification

    Institute of Scientific and Technical Information of China (English)

    LU Gang; ZHENG Ping; JIN Ren-cun; QAISAR Mahmood

    2006-01-01

    Shortcut nitrification for ammonium-rich wastewater is energy-saving and cost-effective procedure that has become one of the hotspots in the field of biological denitrogenation. An orthogonal experiment was performed to study the combined effects of operational parameters on the performance of internal-loop airlift bioreactor for shortcut nitrification. The optimum operational parameters for the shortcut nitrification were found as temperature 35 ℃, pH 8.0, dissolved oxygen concentration 1.0 mg/L, ammonium concentration 4 mmol/L and HRT 16 h, which have different influence on the performance of shortcut nitrification reactor. The pH, temperature and dissolved oxygen concentration have significant bearing on the process. The results showed that the shortcut nitrification reactor could be successfully started up within 42 d, and the reactor performance is steady with minimum NO2-/NOx- of 85.2% , maximum 93.4% and average value of 91.4% in effluent. Based on the analysis of experimental data, a new control strategy named "priority + combination" for shortcut nitrification was suggested. Through this strategy, the startup and operation of shortcut nitrification for ammonium-rich sludge digester liquids were optimized. The control strategy works well to keep the reactor operation in steady state and in achieving high-efficiency for shortcut nitrification.

  18. [Current strategy in PCI for CTO].

    Science.gov (United States)

    Asakura, Yasushi

    2011-02-01

    Recently, CTO PCI has come into wide use all over the world and it has been standardized. The 1st step is an antegrade approach using single wire. The 2nd strategy would be parallel wire technique. And the next would be a retrograde approach. In this method, retrograde wiring with Corsair is done at first. If it is successful, externalization is established using 300 cm wire, and this system is able to provide strong back-up support. If it fails, reverse CART technique is the next step. IVUS guided wiring is a last resort. The 2nd wire is manipulated with IVUS guidance. Now, initial success rate is more than 90% with these methods.

  19. Current management strategy of hepatocellular carcinoma

    Institute of Scientific and Technical Information of China (English)

    Bernardino Rampone; Beniamino Schiavone; Antonio Martino; Carmine Viviano; Giuseppe Confuorto

    2009-01-01

    Hepatocellular carcinoma (HCC) still remains a considerable challenge for surgeons. Surgery, including liver transplantation, is the most important therapeutic approach for patients with this disease. HCC is frequently diagnosed at advanced stages and has a poor prognosis with a high mortality rate even when surgical resection has been considered potentially curative. This brief report summarizes the current status of the management of this malignancy and includes a short description of new pharmacological approaches in HCC treatment.

  20. [Current treatment strategies for paediatric burns].

    Science.gov (United States)

    Küntscher, M V; Hartmann, B

    2006-06-01

    Paediatric burns occupy the third place in the severe accident statistics in Germany after traffic injuries and drowning. The paper reviews current treatment concepts of pre-hospital management, fluid resuscitation and surgical therapy in paediatric burned patients. Specific features in the approximation of the total body surface area burn and indications for transfer of paediatric burn victims to specialized units are discussed. The therapy of severe paediatric burns requires an interdisciplinary team consisting of especially skilled plastic or paediatric surgeons,anaesthetists, psychiatrists or psychologists, specifically trained nurses, physiotherapists and social workers. The rehabilitation process starts basically with admission to the burn unit. A tight cooperation between therapists and the relatives of the paediatric burn victim is needed for psychological recovery and reintegration into society.'The adaptation to the suffered trauma resulting in life-long disability and disfigurement is the main task of psychotherapy.

  1. Current drug discovery strategies against arenavirus infections.

    Science.gov (United States)

    Pasquato, Antonella; Burri, Dominique J; Kunz, Stefan

    2012-11-01

    Arenaviruses are a large group of emerging viruses including several causative agents of severe hemorrhagic fevers with high mortality in man. Considering the number of people affected and the currently limited therapeutic options, novel efficacious therapeutics against arenaviruses are urgently needed. Over the past decade, significant advances in knowledge about the basic virology of arenaviruses have been accompanied by the development of novel therapeutics targeting different steps of the arenaviral life cycle. High-throughput, small-molecule screens identified potent and broadly active inhibitors of arenavirus entry that were instrumental for the dissection of unique features of arenavirus fusion. Novel inhibitors of arenavirus replication have been successfully tested in animal models and hold promise for application in humans. Late in the arenavirus life cycle, the proteolytic processing of the arenavirus envelope glycoprotein precursor and cellular factors critically involved virion assembly and budding provide further promising 'druggable' targets for novel therapeutics to combat human arenavirus infection.

  2. Neurocysticercosis: Diagnostic problems & current therapeutic strategies

    Science.gov (United States)

    Rajshekhar, Vedantam

    2016-01-01

    Neurocysticercosis (NCC) is the most common single cause of seizures/epilepsy in India and several other endemic countries throughout the world. It is also the most common parasitic disease of the brain caused by the cestode Taenia solium or pork tapeworm. The diagnosis of NCC and the tapeworm carrier (taeniasis) can be relatively inaccessible and expensive for most of the patients. In spite of the introduction of several new immunological tests, neuroimaging remains the main diagnostic test for NCC. The treatment of NCC is also mired in controversy although, there is emerging evidence that albendazole (a cysticidal drug) may be beneficial for patients by reducing the number of seizures and hastening the resolution of live cysts. Currently, there are several diagnostic and management issues which remain unresolved. This review will highlight some of these issues. PMID:28139530

  3. Neurocysticercosis: Diagnostic problems & current therapeutic strategies

    Directory of Open Access Journals (Sweden)

    Vedantam Rajshekhar

    2016-01-01

    Full Text Available Neurocysticercosis (NCC is the most common single cause of seizures/epilepsy in India and several other endemic countries throughout the world. It is also the most common parasitic disease of the brain caused by the cestode Taenia solium or pork tapeworm. The diagnosis of NCC and the tapeworm carrier (taeniasis can be relatively inaccessible and expensive for most of the patients. In spite of the introduction of several new immunological tests, neuroimaging remains the main diagnostic test for NCC. The treatment of NCC is also mired in controversy although, there is emerging evidence that albendazole (a cysticidal drug may be beneficial for patients by reducing the number of seizures and hastening the resolution of live cysts. Currently, there are several diagnostic and management issues which remain unresolved. This review will highlight some of these issues.

  4. A dual mode operated boost inverter and its control strategy for ripple current reduction in single-phase uninterruptible power supplies

    DEFF Research Database (Denmark)

    Tang, Y.; Yao, W.; Blaabjerg, Frede

    2015-01-01

    In single-phase uninterruptible power supply (UPS) applications, it is well known that the AC side instantaneous power is not constant by nature. The resulting input current from the DC source side will inevitably contain low frequency ripple components that may largely deteriorate the system...

  5. 车载超级电容储能系统间接电流控制策略%Indirect Current Control Strategy of On-Board Supercapacitor Energy Storage System of Railway Vehicle

    Institute of Scientific and Technical Information of China (English)

    赵坤; 王椹榕; 王德伟; 杨奇平; 游小杰

    2011-01-01

    This paper discusses the control strategy of energy management in single railway vehicle with a on-board supercapacitor energy storage system.First,the structure of the energy storage system is introduced.Second,the model of energy storage system is built and a method to design the current loop for bi-directional DC-DC converter for energy storage is proposed.Finally,an indirect current control strategy is established to ensure an optimal power flow of single railway vehicle.The simulation and the experimental results verify that the new control strategy can avoid the voltage fluctuation and regeneration failure.%主要探讨了单列车车载超级电容能量管理系统的控制方法。首先对车载超级电容储能系统进行介绍;然后建立超级电容储能系统的数学模型,给出了超级电容储能系统充放电电流控制环的设计方法,提出了一种车载超级电容储能系统间接电流能量管理控制策略;最后通过仿真和实验结果证明该控制策略可以有效地抑制受电弓处电压波动,防止再生失效。

  6. Antibiotic resistance: current issues and future strategies

    Directory of Open Access Journals (Sweden)

    Giancarlo Scarafile

    2016-09-01

    Full Text Available The antibiotic resistance (antimicrobial resistance – AMR and the particular emergence of multi-resistant bacterial strains, is a problem of clinical relevance involving serious threats to public health worldwide. From early this decade, a lot of studies have demonstrated a significant increase in the rates of antibiotic resistance by bacterial pathogens responsible for nosocomial and community infections all over the world. The AMR leads to a reduced drug efficacy in the treatment options available and therefore, to an increase in mortality rates. The original causes of the phenomenon are: environmental factors which favor a mutation of the genetic bacterial inheritance, thereby inhibiting the active ingredient of the antibiotics; unsuitable administering of antibiotics in veterinary, incorrect taking both in hospitals and at home and, lately, lack of investments in the development of new drugs. The alarming epidemiological data prompted the World Health Organization (WHO in 2011 to coin the slogan "No action today, no cure tomorrow" in order to immediately implement a new strategy to improve the use of available drugs and to accelerate the introduction of new ones through a new phase of research involving private and public institutions. The European Union has stressed that the surveillance is considered an essential factor for an effective response to this problem but it has also highlighted that the results produced have been lower than expectations because of serious shortcomings such as lack of methodological standards, insufficient data sharing and no coordination among European countries. In Italy the situation is much more troubling; in fact, according to the Ministry of Health, 5000-7000 yearly deaths are deemed due to nosocomial infections, with an annual cost of more than 100 million €.These figures explain how the fight against infections is far from being won. The purpose of this review is to analyze the basic causes of the

  7. 级联式光伏电站直流并网拓扑及其控制策略%Topology of direct-current connecting cascaded photo-voltaic power station to power grid and its control strategy

    Institute of Scientific and Technical Information of China (English)

    罗宇强; 谭建成; 董国庆

    2016-01-01

    In order to solve long-distance integration of photovoltaic (PV) power station to power grid, and improve the system stability of grid-connected PV power station, the PV power stationis integrated with voltage source converter high voltage direct current (VSC-HVDC) system, a topology of direct-current connecting cascaded photovoltaic power station to power grid via VSC-HVDC systemis proposed. The voltage characteristics of PV module and the control strategy for PV module and DC voltage control strategy for VSC stationare analyzed, thus, an improved control strategy of DC voltage margin & droopis put forward. The system and proposed control strategyare simulated under PSCAD/EMDTC electromagnetic transient software by different irradiation conditions.Simulation results show the feasibility of thesystem, indicating that the proposed control strategy caneffectively maintain the system voltage stability of PV power station.%为解决光伏电站远距离输送并网问题,同时提高光伏电站并网系统稳定性,将光伏电站与电压源型高压直流(Voltage Source Converter-High Voltage Direct Current,VSC-HVDC)输电系统相结合,设计了一种光伏电站通过级联直流变换器经 VSC-HVDC 输电线路并网拓扑方案。研究了光伏发电模块均压特性,分析了光伏发电模块控制策略和VSC换流站直流电压控制策略,提出了改进的直流电压-功率偏差斜率控制策略。在PSCAD/EMDTC电磁暂态软件下进行了不同光照强度仿真分析。仿真结果验证了系统可行性,表明了所提出控制策略有效保持光伏电站系统电压稳定性。

  8. Capacitor Current Feedback-Based Active Resonance Damping Strategies for Digitally-Controlled Inductive-Capacitive-Inductive-Filtered Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Lorzadeh, Iman; Askarian Abyaneh, Hossein; Savaghebi, Mehdi

    2016-01-01

    attracted considerable attention due to its effective damping performance and simple implementation. This paper thus presents a state-of-the-art review of resonance and stability characteristics of CCF-based AD approaches for a digitally-controlled LCL filter-based grid-connected inverter taking...

  9. 40 CFR 52.07 - Control strategies.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategies. 52.07 Section 52.07... PROMULGATION OF IMPLEMENTATION PLANS General Provisions § 52.07 Control strategies. (a) Each subpart specifies in what respects the control strategies are approved or disapproved. Where emission limitations...

  10. [Control strategies against Varroa mites].

    Science.gov (United States)

    Lodesani, M

    2004-06-01

    In many cases, the easiest way to control a pest or a pathogen is to resort to chemical treatments. In the short period this option is often the most convenient economically and usually does not require refined knowledge of the biology of the pest. Many efforts have been directed to develop chemical treatments against Varroa destructor Anderson & Trueman. Nowadays, product based on organic acids, essential oils, pyrethroids, organophosphate, and formamidine are available. Resistance is serious problem in the chemotherapy of parasites and pathogens of the honeybee. High-level resistance to several active substances (the pyrethroids acrinathrin, flumethrin, fluvalinate; the organophosphate coumaphos; the formamidine amitraz) was detected with laboratory assays in different varroa populations and caused failure of the control in the field. At the end of the '80s, products based on pyrethroids, very effective against the mite, but without any appreciable side effect on bees, became available. Resistance to fluvalinate in Italy and later in other countries caused serious damage to beekeeping; early detection was crucial to reduce losses. The problem of developing suitable treatments was difficult in the case of the varroa mite because most substances active against V. destructor have unacceptable side effects on bees. The idea that the mite could be controlled indefinitely with these strategies began to gain ground.

  11. Physical mechanism of beam halo-chaos formation for high-current proton beam in a periodic-focusing channels and a nonlinear control strategy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The physical mechanism of the halo-chaos formation for a high intensity proton beam in a periodic-fo cusing channel is analyzed using the transfer mahix theory and a qualiative analysis method.Particles-in-cell simula tims are further used to explore the mechanism of the beam halo-chaos fomation, which concerns not only with thc non linear effect of the beam space charge but also with the lransverse energy exchange belween the particles and the particle core. as well as the chaos generated by the nonlinear resonance ovcrlap. A nonlinear control method is proposed for con trolling tie haho-chaos. Simulation results show lhal the melhod is efhclivc. Somc potemlial applications of the halo chaos conlrol in experimenls are discussed.

  12. Finding current evidence: search strategies and common databases.

    Science.gov (United States)

    Gillespie, Lesley Diane; Gillespie, William John

    2003-08-01

    With more than 100 orthopaedic, sports medicine, or hand surgery journals indexed in MEDLINE, it is no longer possible to keep abreast of developments in orthopaedic surgery by reading a few journals each month. Electronic resources are easier to search and more current than most print sources. We provide a practical approach to finding useful information to guide orthopaedic practice. We focus first on where to find the information by providing details about many useful databases and web links. Sources for identifying guidelines, systematic reviews, and randomized controlled trials are identified. The second section discusses how to find the information, from the first stage of formulating a question and identifying the concepts of interest, through to writing a simple strategy. Sources for additional self-directed learning are provided.

  13. 苏州市麦田草害现状及防除对策%Current Status and Control Strategies of Weeds in Wheat Field of Suzhou City

    Institute of Scientific and Technical Information of China (English)

    张国彪; 沈晴

    2014-01-01

    加重江苏省苏州市麦田杂草发生的原因包括免耕栽培的推广、稻草全量还田、草相变化、除草剂使用不科学等。要实现控草目标,必须坚持综合治理,立足“一封一杀”的化除策略并科学把好麦田化除技术关。%Weed problems in wheat field of Suzhou City have become more serious in association with changes in the cul -tural practices , including the promotion of no -tillage cultivation , leaving all the straw in the field from rotational rice crop, weed population shifts , and improper use of herbicides .For effective weed control , farmers should adhere to inte-grated practices based on prevention and management , including the judicious use of chemical methods available in wheat .

  14. Steady Fault Current Calculation Model of Doubly-fed Induction Generator Considering Grid-side Converter Current and Different Control Strategies%计及 GSC 电流和控制策略的 DFIG 稳态故障电流计算模型

    Institute of Scientific and Technical Information of China (English)

    陈鹏; 张哲; 尹项根; 肖繁; 杨增力; 王力军

    2016-01-01

    The fault current of doubly‐fed induction generator ( DFIG ) is highly complicated when a symmetrical or asymmetrical fault occurs in the grid . Especially , when DFIG s crowbar is not input under nonsevere fault conditions , the fault current of DFIG fed into the grid is rated to its control strategies , the grid s reactive power demand , converters capacity , etc . In order to meet the demand of fault analysis and relaying protection setting for the grid with DFIGs , according to different control strategies of DFIG during the fault , this paper puts forward a novel steady fault current calculation model of DFIG considering grid side converter current and different control strategies . Then , the grid‐side converter current influence on DFIG s fault current is analyzed . Finally , the correctness of the model proposed is verified by digital simulation .%电网故障情况下,双馈风电机组(DFIG )的故障电流特性非常复杂,特别是 DFIG 的撬棒保护未动作时,其馈入电网的故障电流与其所采用的低电压穿越控制策略以及网侧变流器(GSC)特性等因素有关。为满足含 DFIG 的电网故障分析和保护整定计算的需求,针对 DFIG 的几种典型低电压穿越控制策略,分别建立了计及 GSC 电流影响的 DFIG 统一稳态故障电流计算模型,并通过数字仿真验证了所提出的故障电流计算模型的正确性。

  15. A Comparative Study between Two Control Strategies for Matrix Converter

    OpenAIRE

    BENDIABDELLAH, A.; BACHIR, G.

    2009-01-01

    The authors compare two control strategies for direct AC-AC matrix converters; namely the Venturini method and the scalar strategy control method. The performance comparison of the two strategies is made under unbalanced distorted torque, rotor speed and stator current operation. The simulation of the three-phase matrix converter feeding an induction motor was accomplished by means of the Matlab/Simulink software. This package makes it possible to simulate the dynamic systems in a simple wa...

  16. Adaptive Current Control with PI-Fuzzy Compound Controller for Shunt Active Power Filter

    Directory of Open Access Journals (Sweden)

    Juntao Fei

    2013-01-01

    Full Text Available An adaptive control technology and PI-fuzzy compound control technology are proposed to control an active power filter (APF. AC side current compensation and DC capacitor voltage tracking control strategy are discussed and analyzed. Model reference adaptive controller for the AC side current compensation is derived and established based on Lyapunov stability theory; proportional and integral (PI fuzzy compound controller is designed for the DC side capacitor voltage control. The adaptive current controller based on PI-fuzzy compound system is compared with the conventional PI controller for active power filter. Simulation results demonstrate the feasibility and satisfactory performance of the proposed control strategies. It is shown that the proposed control method has an excellent dynamic performance such as small current tracking error, reduced total harmonic distortion (THD, and strong robustness in the presence of parameters variation and nonlinear load.

  17. Control strategies for demand controlled ventilation in dwellings

    DEFF Research Database (Denmark)

    Nielsen, Toke Rammer; Drivsholm, Christian

    2011-01-01

    . In the studied house two control strategies were tested. A simple strategy where all sensors and controls were located in the air handling unit and only the speed of the fans can be controlled, and a complex strategy where sensors were placed in each room and where individual control of air flow in each room...

  18. The Research of A Novel Control Strategy on Torque Ripple for Brushless Direct Current Motor%无刷直流电机转矩波动的新型控制策略研究

    Institute of Scientific and Technical Information of China (English)

    杨晓武; 李干蓉; 李劲松

    2012-01-01

    The advantage and application area of Brushless Direct Current Motor(BLDCM) was described, the relative mathematic model was built and the effect of electromagnetic torque ripple on the performance of BLDCM was elaborat- ed. The paper discussed factors that affected the torque ripple from the case of the ideal back-EMF and non-ideal back-EMF for BLDCM, then the relevant control strategy are put forward to minimize the torque ripple. The strategy com- bines the advanced commutation with the current control to minimize the torque ripple caused by non-ideal back-EMF. Finally, the paper built simulation model for BLDCM by using software MATLAB according to the proposed control strat- egy targeted at torque ripple, the experimental simulation results show that the proposed control strategy for reducing torque ripple is correct and reasonable.%在介绍无刷直流电机的优点及其应用领域的基础上,建立了电机的基本数学模型,并且阐述了其电磁转矩波动对电机运行中性能的影响,重点从理想反电动势无刷直流电机和非理想反电动势无刷直流电机两种情况下分析电磁转矩波动的因素,并采用相对的控制策略来控制电磁转矩波动;提前角开通换相法与电流控制相结合的控制策略,最后,利用MATLAB仿真软件组建了无刷直流电机的仿真模型,仿真实验结果验证了所提出的转矩波动控制策略的合理性和正确性。

  19. Control Strategy for Cascaded Medium - High Voltage STATCOM

    Directory of Open Access Journals (Sweden)

    Libing Chen

    2013-12-01

    Full Text Available Control strategy is researched for cascaded medium high static synchronous compensator to provide synthetic compensation ability of reactive power, harmonics and asymmetric currents. Basing on selective harmonic compensation strategy, a reference current detection method utilizing the combination of synchronous reference frame transformation and discrete Fourier transformation is proposed. The tracking control of instruction current is implemented by multi-carrier pulse width modulation (PWM. In allusion to the multi-carrier PWM, the capacitor voltage balancing control at the dc side is realized by a type of software based on the energy balance principle of the inverter bridge. The proposed control strategy is convenient for engineering implementation given its low calculation burden and simplicity. The effectiveness of the proposed control strategy is proven by both simulation and experimental results.

  20. Signal Processing Strategies for Cochlear Implants Using Current Steering

    Directory of Open Access Journals (Sweden)

    Waldo Nogueira

    2009-01-01

    Full Text Available In contemporary cochlear implant systems, the audio signal is decomposed into different frequency bands, each assigned to one electrode. Thus, pitch perception is limited by the number of physical electrodes implanted into the cochlea and by the wide bandwidth assigned to each electrode. The Harmony HiResolution bionic ear (Advanced Bionics LLC, Valencia, CA, USA has the capability of creating virtual spectral channels through simultaneous delivery of current to pairs of adjacent electrodes. By steering the locus of stimulation to sites between the electrodes, additional pitch percepts can be generated. Two new sound processing strategies based on current steering have been designed, SpecRes and SineEx. In a chronic trial, speech intelligibility, pitch perception, and subjective appreciation of sound were compared between the two current steering strategies and standard HiRes strategy in 9 adult Harmony users. There was considerable variability in benefit, and the mean results show similar performance with all three strategies.

  1. A Synthesis of Language Learning Strategies: Current Issues, Problems and Claims Made in Learner Strategy Research

    Science.gov (United States)

    Barjesteh, Hamed; Mukundan, Jayakaran; Vaseghi, Reza

    2014-01-01

    The current paper presented theoretical assumptions behind language learning strategies (LLS) and an overview of methods used to identify learners' strategies, first, and then summarized what have been reported from large number of descriptive studies of strategies by language learners. Moreover, the paper tried to present the variety of…

  2. Study of the Current Compensation Control Strategy for EPS in High-speed and Large Steering Angle Operation%高速大转角工况下EPS电流补偿控制策略研究

    Institute of Scientific and Technical Information of China (English)

    吴星男; 江浩斌; 唐斌; 王志忠

    2013-01-01

    为提高车辆在高速大转角工况下的横向稳定性,以装备管柱式EPS的某微型乘用车为研究对象,建立其非线性3自由度整车模型,对车辆转向特性和转向行驶稳定性进行理论分析;在没有电子稳定程序或车辆动态稳定性控制装置的情况下,引入可控的补偿电流对EPS控制策略进行改进,并在matlab/simulink中进行仿真分析。结果表明,所研究的EPS电流补偿控制策略有效提高了高速大转角时车辆转向系统阻尼,增强了车辆的横向稳定性和驾驶员“路感”,使车辆的横摆运动得到良好控制。%In order to improve the vehicle's lateral stability in high-speed and large steering angle operation, the researchers established a 3-DOF model of the whole vehicle using a mini passenger car equipped with column-type EPS as research object, and analyzed vehicle steering characteristic and steering stability theoretically. A controllable compensation current has been introduced to improve the control strategy for EPS with the absence of electronic stability program (ESP) or vehicle dynamic control (VDC) system. The simulation was made in Matlab/Simulink. The results show that the EPS current compensation control strategy has effectively increased the steering system damping in high-speed and large steering angle operation, it has also enhanced the lateral stability and the road feel. The vehicle's yaw motion is well controlled.

  3. Occupant satisfaction with two blind control strategies

    DEFF Research Database (Denmark)

    Karlsen, Line Røseth; Heiselberg, Per Kvols; Bryn, Ida

    2015-01-01

    Highlights •Occupant satisfaction with two blind control strategies has been studied. •Control based on cut-off position of slats was more popular than closed slats. •Results from the study are helpful in development of control strategies for blinds. •The results give indications of how blinds...

  4. Persistent organic pollutants control strategy in China

    Institute of Scientific and Technical Information of China (English)

    SHI Ya-juan; LU Yong-long; ZHANG Hong; WANG Tie-yu; XING Ying

    2005-01-01

    The development of Persistent Organic Pollutants(POPs) control policy in China in the context of international concerns on POPs was reviewed. The aspects of the Chinese POPs control strategies were analyzed, and compared with those of developed counterparts (e.g. US, EU, Japan). Currently, while the legal framework on POPs management, which complies with international guidelines has been established, it should be improved in the areas of special POPs management, risk assessment, the precautionary principle, lifecycle management and technical support capacity. The analysis of Chinese POPs policy and suggestions for strengthening the sciencebased decision making capacity are not only useful for Chinese decision-makers, but also a case study for developing world and make a great contribution for the global elimination of POPs to make a toxic-free future.

  5. Control Strategy for Microgrid Inverter under Unbalanced Grid Voltage Conditions

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Liu, Wenzhao; Zhang, X.

    2014-01-01

    This paper presents the theoretical analysis of the inherent reason of current harmonic and power oscillation phenomena in case of operating the microgrid inverter under unbalanced grid voltage conditions. In order to flexibly control the current harmonic and power oscillation, a new stationary...... frame control strategy is proposed. It has a simple control structure due to no need of a phase-locked loop and voltage/current positive/negative sequence extraction calculation. The coordinate control of power and current quality is achieved, which enhances the operation performance of microgrid...

  6. THE CURRENT STATE OF RISK-CONTROLLING

    Directory of Open Access Journals (Sweden)

    Orlov A. I.

    2014-04-01

    Full Text Available The concept of risk-controlling is based on the general theory of risk. The current state of risk-management in our country is reviewed. We also discuss the research on risk-controlling made in the BMSTU Laboratory of economic-mathematical methods in controlling

  7. A computer simulation approach to measurement of human control strategy

    Science.gov (United States)

    Green, J.; Davenport, E. L.; Engler, H. F.; Sears, W. E., III

    1982-01-01

    Human control strategy is measured through use of a psychologically-based computer simulation which reflects a broader theory of control behavior. The simulation is called the human operator performance emulator, or HOPE. HOPE was designed to emulate control learning in a one-dimensional preview tracking task and to measure control strategy in that setting. When given a numerical representation of a track and information about current position in relation to that track, HOPE generates positions for a stick controlling the cursor to be moved along the track. In other words, HOPE generates control stick behavior corresponding to that which might be used by a person learning preview tracking.

  8. Control Strategy Tool (CoST)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The EPA Control Strategy Tool (CoST) is a software tool for projecting potential future control scenarios, their effects on emissions and estimated costs. This tool...

  9. Current Models and Innovative Strategies in Management Education in China.

    Science.gov (United States)

    Wang, Zhong-Ming

    1999-01-01

    Current models of management education in China include national training, on-the-job technical training, and the national master's of business administration supervisory committee. Effective strategies being used include teamwork, process skills, action learning, cross-cultural management learning, and competency-based management development. (SK)

  10. Robust missile feedback control strategies

    NARCIS (Netherlands)

    Trottemant, E.J.; Scherer, C.W.; Weiss, M.; Vermeulen, A.

    2010-01-01

    The nature of the missile interception problem with two noncooperative players leads to the field of differential games. Introducing nonlinear uncertain models can potentially lead to nonexistence of game theoretic equilibrium strategies, computationally intractable problems, and/or highly reduced p

  11. Public authority control strategy for opinion evolution in social networks

    Science.gov (United States)

    Chen, Xi; Xiong, Xi; Zhang, Minghong; Li, Wei

    2016-08-01

    This paper addresses the need to deal with and control public opinion and rumors. Existing strategies to control public opinion include degree, random, and adaptive bridge control strategies. In this paper, we use the HK model to present a public opinion control strategy based on public authority (PA). This means utilizing the influence of expert or high authority individuals whose opinions we control to obtain the optimum effect in the shortest time possible and thus reach a consensus of public opinion. Public authority (PA) is only influenced by individuals' attributes (age, economic status, and education level) and not their degree distribution; hence, in this paper, we assume that PA complies with two types of public authority distribution (normal and power-law). According to the proposed control strategy, our experiment is based on random, degree, and public authority control strategies in three different social networks (small-world, scale-free, and random) and we compare and analyze the strategies in terms of convergence time (T), final number of controlled agents (C), and comprehensive efficiency (E). We find that different network topologies and the distribution of the PA in the network can influence the final controlling effect. While the effect of PA strategy differs in different network topology structures, all structures achieve comprehensive efficiency with any kind of public authority distribution in any network. Our findings are consistent with several current sociological phenomena and show that in the process of public opinion/rumor control, considerable attention should be paid to high authority individuals.

  12. Optimal control of anthracnose using mixed strategies.

    Science.gov (United States)

    Fotsa Mbogne, David Jaures; Thron, Christopher

    2015-11-01

    In this paper we propose and study a spatial diffusion model for the control of anthracnose disease in a bounded domain. The model is a generalization of the one previously developed in [15]. We use the model to simulate two different types of control strategies against anthracnose disease. Strategies that employ chemical fungicides are modeled using a continuous control function; while strategies that rely on cultivational practices (such as pruning and removal of mummified fruits) are modeled with a control function which is discrete in time (though not in space). For comparative purposes, we perform our analyses for a spatially-averaged model as well as the space-dependent diffusion model. Under weak smoothness conditions on parameters we demonstrate the well-posedness of both models by verifying existence and uniqueness of the solution for the growth inhibition rate for given initial conditions. We also show that the set [0, 1] is positively invariant. We first study control by impulsive strategies, then analyze the simultaneous use of mixed continuous and pulse strategies. In each case we specify a cost functional to be minimized, and we demonstrate the existence of optimal control strategies. In the case of pulse-only strategies, we provide explicit algorithms for finding the optimal control strategies for both the spatially-averaged model and the space-dependent model. We verify the algorithms for both models via simulation, and discuss properties of the optimal solutions. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Decoupling Control Strategy for Single Phase SPWM Parallel Inverters

    Institute of Scientific and Technical Information of China (English)

    Shun-Gang Xu; Jian-Ping Xu; Tai-Qiang Cao

    2009-01-01

    A decoupling control strategy of inverter parallel system is proposed based on the equivalent output impedance of single phase voltage source SPWM (sinusoidal pulse width modulation) inverter. The active power and reactive power are calculated in terms of output voltage and current of the inverter, and sent to the other inverters in the parallel system via controller area network (CAN) bus. By calculating and decoupling the circumfluence of the active power and reactive power, the inverters can share load current via the regulation of the reference-signal phase and amplitude. Experimental results of an 110V/2kVA inverter parallel system show the feasibility of the decoupling control strategy.

  14. An optimal current observer for predictive current controlled buck DC-DC converters.

    Science.gov (United States)

    Min, Run; Chen, Chen; Zhang, Xiaodong; Zou, Xuecheng; Tong, Qiaoling; Zhang, Qiao

    2014-05-19

    In digital current mode controlled DC-DC converters, conventional current sensors might not provide isolation at a minimized price, power loss and size. Therefore, a current observer which can be realized based on the digital circuit itself, is a possible substitute. However, the observed current may diverge due to the parasitic resistors and the forward conduction voltage of the diode. Moreover, the divergence of the observed current will cause steady state errors in the output voltage. In this paper, an optimal current observer is proposed. It achieves the highest observation accuracy by compensating for all the known parasitic parameters. By employing the optimal current observer-based predictive current controller, a buck converter is implemented. The converter has a convergently and accurately observed inductor current, and shows preferable transient response than the conventional voltage mode controlled converter. Besides, costs, power loss and size are minimized since the strategy requires no additional hardware for current sensing. The effectiveness of the proposed optimal current observer is demonstrated experimentally.

  15. Optimal control of stochastic magnetization dynamics by spin current

    Science.gov (United States)

    Wang, Yong; Zhang, Fu-Chun

    2013-05-01

    Fluctuation-induced stochastic magnetization dynamics plays an important role in spintronics devices. Here we propose that it can be optimally controlled by spin currents to minimize or maximize the Freidlin-Wentzell action functional of the system hence to increase or decrease the probability of the large fluctuations. We apply this method to study the thermally activated magnetization switching problem and to demonstrate the merits of the optimal control strategy.

  16. Current and emergent strategies for disinfection of hospital environments.

    Science.gov (United States)

    Abreu, Ana C; Tavares, Rafaela R; Borges, Anabela; Mergulhão, Filipe; Simões, Manuel

    2013-12-01

    A significant number of hospital-acquired infections occur due to inefficient disinfection of hospital surfaces, instruments and rooms. The emergence and wide spread of multiresistant forms of several microorganisms has led to a situation where few compounds are able to inhibit or kill the infectious agents. Several strategies to disinfect both clinical equipment and the environment are available, often involving the use of antimicrobial chemicals. More recently, investigations into gas plasma, antimicrobial surfaces and vapour systems have gained interest as promising alternatives to conventional disinfectants. This review provides updated information on the current and emergent disinfection strategies for clinical environments.

  17. ORGANIZATIONAL CHANGE STRATEGIES IN THE CURRENT ECONOMIC AND SOCIAL CONTEXT

    Directory of Open Access Journals (Sweden)

    Iuliana, TALMACIU

    2014-11-01

    Full Text Available The purpose of this paper is to analyze the main strategies for implementing organizational changes in the current social and economic context, characterized by an unprecedented dynamism. As a result, the paper presents the results of the research that have led to the identification of the factors determining the application of a particular strategy or even the usage of their mix. To achieve the established objectives set we have used as a research method the content analysis of various Romanian and foreign authors' work.

  18. PERFUSION SYSTEM CONTROLLER STRATEGIES DURING AN ECMO SUPPORT

    OpenAIRE

    2014-01-01

    In this work modelling and control of Perfusion system is presented. The Perfusion system simultaneously controls the partial pressures during Extra Corporeal Membrane Oxygenation (ECMO) support. The main Problem in ECMO system is exchange of Blood Gases in the Artificial Lung (Oxygenator).It is a highly Nonlinear Process comprising time-varying parameters, and varying time delays, it is currently being controlled manually by trained Perfusionist. The new control strategy implemen...

  19. Human Operator Control Strategy Model.

    Science.gov (United States)

    1980-04-01

    fashion. HOPE reflects the two-store theory of memory current in the psycho- logical literature ( Atkinson & Shiffrin , 1968; Broadbent, 1971). Two...uncertainty. In P.M.A. Rabbit & S. Dornic (Eds.), Attention and performance V. New York: Academic Press, 1975. Atkinson , R. C., & Shiffrin , R. M. Human...48 2. The Perception Process ... ............... 50 3. The Command Memory and Command Selection Process

  20. Soil Contamination and Remediation Strategies. Current research and future challenge

    Science.gov (United States)

    Petruzzelli, G.

    2012-04-01

    eliminating the source of pollution, but also on blocking the pathways from contaminants to receptors or reducing the exposure to contaminants,. Future challenge integration of sustainability into remediation decision-making. Soil is not a waste! There is a growing interest in the clean up approaches that maintain soil quality after remediation treatments. This issue is of great importance in the U.S.A. where the EPA from 2009 is promoting innovative clean-up strategies (Green Remediation). Green remediation is defined as the practice of considering all environmental effects of remedy and incorporating options to maximize environmental benefit of cleanup actions . These remediation strategies restore contaminated sites to productive use with a great attention to the global environmental quality, including the preservation of soil functionality according to the following principles: use minimally invasive technologies; use passive energy technologies such as bioremediation and phytoremediation as primary remedies or finishing steps where possible and effective; minimize soil and habitat disturbance; minimize bioavailability of contaminants trough adequate contaminant source and plume control If we move from the current definition of remedial targets based on total concentrations, technologies with low impact on the environment can be utilized reducing the wrong choice to disposal soil in landfill destroying quickly a not renewable essential resource.

  1. Chemical Biology Strategies for Biofilm Control.

    Science.gov (United States)

    Yang, Liang; Givskov, Michael

    2015-08-01

    Microbes live as densely populated multicellular surface-attached biofilm communities embedded in self-generated, extracellular polymeric substances (EPSs). EPSs serve as a scaffold for cross-linking biofilm cells and support development of biofilm architecture and functions. Biofilms can have a clear negative impact on humans, where biofilms are a common denominator in many chronic diseases in which they prime development of destructive inflammatory conditions and the failure of our immune system to efficiently cope with them. Our current assortment of antimicrobial agents cannot efficiently eradicate biofilms. For industrial applications, the removal of biofilms within production machinery in the paper and hygienic food packaging industry, cooling water circuits, and drinking water manufacturing systems can be critical for the safety and efficacy of those processes. Biofilm formation is a dynamic process that involves microbial cell migration, cell-to-cell signaling and interactions, EPS synthesis, and cell-EPS interactions. Recent progress of fundamental biofilm research has shed light on novel chemical biology strategies for biofilm control. In this article, chemical biology strategies targeting the bacterial intercellular and intracellular signaling pathways will be discussed.

  2. A Global Space Control Strategy

    Science.gov (United States)

    2014-12-01

    Russia have sur- passed the post–Cold War taboos of talking about the development of space control activity with the announcement of the fielding of... searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send...and commercial entities seeking a benign environment. It is politically taboo to discuss space control events. Do- ing so runs the risk of creating

  3. Designing a sustainable strategy for malaria control?

    Directory of Open Access Journals (Sweden)

    Mharakurwa Sungano

    2011-08-01

    Full Text Available Abstract Malaria in the 21st century is showing signs of declining over much of its distribution, including several countries in Africa where previously this was not thought to be feasible. Yet for the most part the strategies to attack the infection are similar to those of the 1950s. Three major Journals have recently drawn attention to the situation, stressing the importance of research, describing the successes and defining semantics related to control. But there is a need to stress the importance of local sustainability, and consider somewhat urgently how individual endemic countries can plan and implement the programmes that are currently financed, for the most part, by donor institutions. On an immediate basis research should be more focused on a data driven approach to control. This will entail new thinking on the role of local infrastructure and in training of local scientists in local universities in epidemiology and field malariology so that expanded control programmes can become operational. Donor agencies should encourage and facilitate development of career opportunities for such personnel so that local expertise is available to contribute appropriately.

  4. Comparison of control strategies for DFIG under symmetrical grid voltage dips

    DEFF Research Database (Denmark)

    Chen, Wenjie; Xu, Dehong; Chen, Min;

    2013-01-01

    This paper presents a series of current control strategies for the DFIG under symmetrical grid voltage dips. The controllable range, the damping time constant of the stator natural flux and the torque fluctuations of six control strategies are analyzed and compared. The control strategies which...

  5. Part 2 -- current program integrating strategies and lubrication technology

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, B.

    1996-12-01

    This paper is the second of two that describe the Predictive Maintenance Program for rotating machinery at the Palo Verde Nuclear Generating Station. The Predictive Maintenance program has been enhanced through organizational changes and improved interdisciplinary usage of technology. This paper will discuss current program strategies that have improved the interaction between the Vibration and Lube Oil programs. The {open_quotes}Lube Oil{close_quotes} view of the combined program along with case studies will then be presented.

  6. Current and new strategies for the delivery of antiseptic agents.

    Science.gov (United States)

    Constant, Hélène; Falson, Françoise; Pirot, Fabrice

    2006-07-01

    The present mini-review explores the current methods used for the delivery of antiseptics and topical antimicrobials. Relevance of hand scrub with antiseptic liquid soap (e.g. chlorhexidine, PVP-iodine, triclosan) and alcohol-based hand rub is discussed and compared in terms of bactericidal activity, skin tolerance, and medical staff observance. New strategies for antibacterial delivery focus on the challenge of colloidal drug carrier such as liposomes, micro- and nanoparticles enabling sustained bactericidal effect and effective bacterial targeting.

  7. A Comparative Study between Two Control Strategies for Matrix Converter

    Directory of Open Access Journals (Sweden)

    BENDIABDELLAH, A.

    2009-06-01

    Full Text Available The authors compare two control strategies for direct AC-AC matrix converters; namely the Venturini method and the scalar strategy control method. The performance comparison of the two strategies is made under unbalanced distorted torque, rotor speed and stator current operation. The simulation of the three-phase matrix converter feeding an induction motor was accomplished by means of the Matlab/Simulink software. This package makes it possible to simulate the dynamic systems in a simple way and in graphic environment.

  8. A Current Limiting Strategy to Improve Fault Ride-Through of Inverter Interfaced Autonomous Microgrids

    DEFF Research Database (Denmark)

    Sadeghkhani, Iman; Esmail Hamedani Golshan, Mohamad; Guerrero, Josep M.

    2017-01-01

    With high penetration of distributed energy resources (DER), fault management strategy is of great importance for the distribution network operation. The objective of this paper is to propose a current and voltage limiting strategy to enhance fault ride-through (FRT) capability of inverter......-based islanded microgrids (MGs) in which the effects of inverter control system and inverter topology (four/three-wire) are considered. A threephase voltage-sourced inverter (VSI) with multi-loop control system implemented in synchronous, stationary, and natural reference frames is employed in this study...... for both four- and three-wire configurations. The proposed strategy provides high voltage and current quality during overcurrent conditions, which is necessary for sensitive loads. Several time-domain simulation studies are conducted to investigate the FRT capability of the proposed strategy against both...

  9. Circle Points Discharge Tube Current Controller

    Institute of Scientific and Technical Information of China (English)

    Meng Jinjia; Meng Lisheng

    2005-01-01

    Circle points discharge tube current controller is a new type device to limit theoutput of high voltage discharge current. Circle points uniform corona discharge to form airionization current in the discharge tube. On the outside, even if the discharge electrode is sparkdischarging or the two discharge electrodes are short circuited, the air ionization current in the tuberemains within a stable range, and there is no spark discharge. In this case, when the dischargecurrent only increases slightly, the requirement to limited current is obtained. By installing thecontroller at a discharge pole with a small power but high voltage supply, we can realize the shiftbetween the continuous spark line discharge and corona discharge. This provides a new simpledevice for spark discharge research and is a supplement to the Townsend discharge experiment.

  10. Novel deadbeat power control strategy for grid connected systems

    Directory of Open Access Journals (Sweden)

    Yousry Atia

    2015-09-01

    Full Text Available This paper introduces a novel approach for power control of three phase voltage source inverter (VSI in grid connected distribution generation system. In this approach, the control of active and reactive power is based on deadbeat control strategy. First, the difference between the reference and actual currents are introduced in different approach. Then current to power substitutions are carried out to obtain direct relationship between the required inverter voltage and instantaneous power errors. There is no need for coordinate transformation or PLL, where the required inverter voltage vector calculations carried out in α–β stationary reference frame. The proposed technique introduces two cross coupling components in the control function. Including these two components, the controller can achieve nearly zero steady-state tracking error of the controlled variables. To obtain fixed switching frequency operations, space vector modulation (SVM is used to synthesize the required inverter voltage vector and to generate the switching pulses for the VSI. The proposed strategy has the simplicity of the direct power control (DPC technique and doesn’t require any current control loops. The proposed strategy is experimentally implemented using fixed-point microcontroller. Simulation and experimental results are presented to confirm the superiority of the proposed strategy.

  11. Strategies For Malaria Control In Mangalore City

    OpenAIRE

    Kiran Udaya .N

    1999-01-01

    Research questions: What different strategies should be used to effectively control problem of malaria? Objectives: 1) To study the problem of malaria. 2) To study different strategies for effective control of malaria. Study design: Observational and record based. The problem of malaria was studied for three years from 1996-1998 Participants: Individuals having fever. Setting: Community based in Mangalore City. Study variables: Fever cases, blood slides prepared, slides found positive, agency...

  12. ROBUST INTERNAL MODEL CONTROL STRATEGY BASED PID CONTROLLER FOR BLDCM

    Directory of Open Access Journals (Sweden)

    A.PURNA CHANDRA RAO

    2010-11-01

    Full Text Available All the closed loop control system requires the controller for improvement of transient response of the error signal. Though the tuning of PID controller in real time is bit difficult and moreover it lacks the disturbance rejection capability. This paper presents a tuning of PID parameters based on internal model strategy. The advantageous of the proposed control strategy is well described in the paper. To test the validity of the proposed control, it is implemented in brushless dc motor drive. The mathematical model of brushless dc motor (BLDC is presented for control design. In addition the robustness of the control strategy is discussed. The proposed control strategy possesses good transient responses and good load disturbance response. In addition, the proposed control strategy possesses good tracking ability. To test the effectiveness of the proposed strategy, the BLDC is represented in transfer function model and later implemented in test system. The results are presented to validate the proposed control strategy for BLDC drive.

  13. Hysteresis Current Control of Switched Reluctance Motor in Aircraft Applications

    Directory of Open Access Journals (Sweden)

    Maged N. F. Nashed

    2014-05-01

    Full Text Available The switched reluctance motor (SRM drives have been widely used in aircraft applications due to the motor advantages like high speed operation, simple construction, no windings on rotor. But high torque ripples and acoustic noise are main disadvantages. The current hysteresis chopping control is one of the important control methods for SRM drives. These disadvantages can be limited using the hysteresis or chopping current control. This control strategy makes the torque of SRM maintained within a set of hysteresis bands by applying suitable source voltage. This paper introduces two hysteresis control modes; hard chopping and soft chopping mode. The SRM drive system is modeled in Simulink model using MATLAB/SIMULINK software package.

  14. HTGR Resilient Control System Strategy

    Energy Technology Data Exchange (ETDEWEB)

    Lynne M. Stevens

    2010-09-01

    A preeminent objective for corporate and government organizations is the protection of major investments, which is attained by achieving state awareness, a comprehensive understanding of security and safety, for critical infrastructures. Given the dependence of critical infrastructure on control systems for automation, the integrity of these systems and their ability to provide owner/operators a high degree of state awareness is essential in attaining a high degree of investment protection and public acceptance. Operators as well as government are therefore burdened to ensure they have a timely understanding of the status of their plant or all plants, respectively, to ensure efficient operations and investment and public protection. “This characterization is a significant objective that must consider many aspects of instrumentation, control, and intelligent systems in order to achieve the required result. These aspects include sensory, communication, analysis, decision, and human system interfaces necessary to achieve fusion of data and presentation of results that will provide an understanding of what issues are important and why.

  15. Current strategies for endoscopic management of acute cholangitis.

    Science.gov (United States)

    Isayama, Hiroyuki; Yasuda, Ichiro; Tan, Damien

    2017-04-01

    At the pancreatobiliary session of Endoscopic Forum Japan (EFJ) 2016, current strategies for the endoscopic management of acute cholangitis were discussed. The topics consisted of two major parts, namely endoscopic management of acute cholangitis caused by common bile duct stones (CBDS) and biliary stent occlusion. Endoscopists from nine Japanese high-volume centers along with two overseas centers participated in the questionnaires and discussion. Strategies for management of cholangitis due to CBDS were agreed upon, and the clinical guideline of acute cholangitis (Tokyo guidelines 2013) was accepted. The best timing for drainage in Grade 2 (moderate) cholangitis urgent or early (strategies differed according to the stricture location (distal or hilar) and stent type initially placed (Covered or uncovered metal stent). Strategies for management of cholangitis caused by CBD stones are well established according to the TG13. More evidence is required before further recommendations can be made with regards to cholangitis due to stent occlusion. We aim to clarify this in the near future with questionnaires and consensus from experts. © 2017 The Authors. Digestive Endoscopy © 2017 Japan Gastroenterological Endoscopy Society.

  16. Implementing two DC motor speed control strategies

    Directory of Open Access Journals (Sweden)

    José Danilo Rairán Antolines

    2010-05-01

    Full Text Available While linear control techniques for dynamic systems have been widely tested, systems are not linear in practice. This means that controllers must be re-tuned to make them useful in an experimental setup. This article presents the tuning and re-tuning process for two control strategies: a PID and an algorithm based on the choice of overall transfer function controlling a DC permanent magnet motor. The algorithms’ performance is evaluated and some recommendations are made.

  17. Current control of light by nonreciprocal magnetoplasmonics

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Yongkang, E-mail: yongkang.gong@southwales.ac.uk; Li, Kang; Carver, Sara; Martinez, Juan Jose; Huang, Jungang; Copner, Nigel [Wireless and Optoelectronics Research and Innovation Centre (WORIC), Faculty of Computing, Engineering and Science, University of South Wales, Cardiff CF37 1DL (United Kingdom); Thueux, Yoann; Avlonitis, Nick [Airbus Group Innovations, Quadrant House, Celtic Springs, Coedkernew, NP10 8FZ Newport (United Kingdom)

    2015-05-11

    The ability to actively control light has long been a major scientific and technological goal. We proposed a scheme that allows for active control of light by utilizing the nonreciprocal magnetoplasmonic effect. As a proof of concept, we applied current signal through an ultrathin metallic film in a magneto-plasmonic multilayer and found that dynamic photonic nonreciprocity appears in magnetic-optical material layer due to the magnetic field being induced from current signal and modulates surface plasmon polaritons trapped in the metal surface and the light reflected. The proposed concept provides a possible way for the active control of light and could find potential applications such as ultrafast optoelectronic signal processing for plasmonic nanocircuit technology and ultrafast/large-aperture free-space electro-optic modulation platform for wireless laser communication technology.

  18. Safe current injection strategies for a STATCOM under asymmetrical grid faults

    DEFF Research Database (Denmark)

    Rodriguez, Pedro; Medeiros, Gustavo; Luna, Alvaro;

    2010-01-01

    presents a comprehensive derivation of the proposed STATCOM control strategies to set the reactive current reference under unbalanced grid faults, together with an extensive evaluation using simulation and experimental results from a low-scale laboratory setup in order to verify and validate the dynamic...

  19. THROTTLE CONTROL STRATEGIES IN THE PROCESS OF INTEGRATED POWERTRAIN CONTROL

    Institute of Scientific and Technical Information of China (English)

    Lei Yulong; Gao Bingzhao; Tian Hua; Ge Anlin; Yan Su

    2005-01-01

    Combining with the development of automated manual transmission (AMT), the various throttle control demands are analyzed under different working conditions of AMT such as tracking acceleration pedal, start, shift and so on. Based on simulation, the responding throttle control strategies are proposed, and a simple but effective throttle control method is presented. The testing results have proved that the strategies are effective for improving the pedal tracking precision and the qualities of start and shift.

  20. Current limiting remote power control module

    Science.gov (United States)

    Hopkins, Douglas C.

    1990-01-01

    The power source for the Space Station Freedom will be fully utilized nearly all of the time. As such, any loads on the system will need to operate within expected limits. Should any load draw an inordinate amount of power, the bus voltage for the system may sag and disrupt the operation of other loads. To protect the bus and loads some type of power interface between the bus and each load must be provided. This interface is most crucial when load faults occur. A possible system configuration is presented. The proposed interface is the Current Limiting Remote Power Controller (CL-RPC). Such an interface should provide the following power functions: limit overloading and resulting undervoltage; prevent catastrophic failure and still provide for redundancy management within the load; minimize cable heating; and provide accurate current measurement. A functional block diagram of the power processing stage of a CL-RPC is included. There are four functions that drive the circuit design: rate control of current; current sensing; the variable conductance switch (VCS) technology; and the algorithm used for current limiting. Each function is discussed separately.

  1. Wind farm models and control strategies

    DEFF Research Database (Denmark)

    Sørensen, Poul Ejnar; Hansen, Anca Daniela; Iov, F.;

    2005-01-01

    models for a fixed speed wind turbine with active stall control and a variable speed wind turbine with doubly-fed induction generator. After that, the 3 wind farm concepts and control strategies are described.The 3 concepts are AC connected doubly fed turbines, AC connected active stall turbines and DC......This report describes models and control strategies for 3 different concepts of wind farms. Initially, the potential in improvement of grid integration, structural loads and energy production is investigated in a survey of opportunities. Then simulationmodels are described, including wind turbine...

  2. An adaptive strategy for controlling chaotic system

    Institute of Scientific and Technical Information of China (English)

    曹一家; 张红先

    2003-01-01

    This paper presents an adaptive strategy for controlling chaotic systems. By employing the phase space reconstruction technique in nonlinear dynamical systems theory, the proposed strategy transforms the nonlinear system into canonical form, and employs a nonlinear observer to estimate the uncertainties and disturbances of the nonlinear system, and then establishes a state-error-like feedback law. The developed control scheme allows chaos control in spite of modeling errors and parametric variations. The effectiveness of the proposed approach has been demonstrated through its applications to two well-known chaotic systems : Duffing oscillator and Rǒssler chaos.

  3. Wind farm models and control strategies

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, Poul; Hansen, Anca D.; Iov, F.; Blaabjerg, F.; Donovan, M.H.

    2005-08-01

    This report describes models and control strategies for 3 different concepts of wind farms. Initially, the potential in improvement of grid integration, structural loads and energy production is investigated in a survey of opportunities. Then simulation models are described, including wind turbine models for a fixed speed wind turbine with active stall control and a variable speed wind turbine with doubly-fed induction generator. After that, the 3 wind farm concepts and control strategies are described. The 3 concepts are AC connected doubly fed turbines, AC connected active stall turbines and DC connected active stall turbines. Finally, some simulation examples and conclusions are presented. (au)

  4. An adaptive strategy for controlling chaotic system.

    Science.gov (United States)

    Cao, Yi-Jia; Hang, Hong-Xian

    2003-01-01

    This paper presents an adaptive strategy for controlling chaotic systems. By employing the phase space reconstruction technique in nonlinear dynamical systems theory, the proposed strategy transforms the nonlinear system into canonical form, and employs a nonlinear observer to estimate the uncertainties and disturbances of the nonlinear system, and then establishes a state-error-like feedback law. The developed control scheme allows chaos control in spite of modeling errors and parametric variations. The effectiveness of the proposed approach has been demonstrated through its applications to two well-known chaotic systems: Duffing oscillator and Rössler chaos.

  5. An adaptive strategy for controlling chaotic system

    Institute of Scientific and Technical Information of China (English)

    曹一家; 张红先

    2003-01-01

    This paper presents an adaptive strategy for controlling chaotic systems. By employing the phase space reconstruction technique in nonlinear dynamical systems theory, the proposed strategy transforms the nonlinear system into canonical form, and employs a nonlinear observer to estimate the uncertainties and disturbances of the nonlinear system, and then establishes a state-error-like feedback law. The developed control scheme allows chaos control in spite of modeling errors and parametric variations. The effectiveness of the proposed approach has been demonstrated through its applications to two well-known chaotic systems: Duffing oscillator and Rossler chaos.

  6. 2013 update on current vaccination strategies in puppies and kittens.

    Science.gov (United States)

    Davis-Wurzler, Gina M

    2014-03-01

    Vaccines remain one of the practitioner's greatest tools in preventing disease and maintaining individual and population health. This article is an update to "Current Vaccination Strategies in Puppies and Kittens" published in Veterinary Clinics of North America, Small Animal Practitioner, in May 2006. There are now comprehensive guidelines readily available for small animal practitioners regarding canine and feline pediatric (and adult) vaccination recommendations. Perhaps more importantly, there is an increased dialogue regarding all aspects of preventive medicine, of which vaccination is only a small, yet significant portion; and an increased drive to provide scientific evidence for developing vaccination recommendations.

  7. Digitally Controllable Current Amplifier and Current Conveyors in Practical Application of Controllable Frequency Filter

    Science.gov (United States)

    Polak, Josef; Jerabek, Jan; Langhammer, Lukas; Sotner, Roman; Dvorak, Jan; Panek, David

    2016-07-01

    This paper presents the simulations results in comparison with the measured results of the practical realization of the multifunctional second order frequency filter with a Digitally Adjustable Current Amplifier (DACA) and two Dual-Output Controllable Current Conveyors (CCCII +/-). This filter is designed for use in current mode. The filter was designed of the single input multiple outputs (SIMO) type, therefore it has only one input and three outputs with individual filtering functions. DACA element used in a newly proposed circuit is present in form of an integrated chip and the current conveyors are implemented using the Universal Current Conveyor (UCC) chip with designation UCC-N1B. Proposed frequency filter enables independent control of the pole frequency using parameters of two current conveyors and also independent control of the quality factor by change of a current gain of DACA.

  8. Wolbachia: A biological control strategy against arboviral diseases.

    Science.gov (United States)

    Mohanty, Ipsita; Rath, Animesha; Mahapatra, Namita; Hazra, Rupenangshu K

    2016-01-01

    Vector-borne diseases particularly those transmitted by mosquitoes like Dengue are among the leading causes of mortality and morbidity in human population. There are no effective vaccines or treatment against dengue fever till date and the control methods are limited. So, new approaches are urgently in need to reverse these trends. Vector control is currently the primary intervention tool. Strategies that reduce or block pathogen transmission by mosquitoes have been proposed as a means of augmenting current control measures to reduce the growing burden of vector-borne diseases. Wolbachia an endosymbiont of arthropod vectors is being explored as a novel ecofriendly control strategy. Studies in Drosophila have shown that Wolbachia can confer resistance to diverse RNA viruses and protect flies from virus-induced mortality. This review was focused on biology of the Wolbachia and its implication as a control measure for arboviral diseases mainly Dengue and Chikungunya.

  9. Therapeutic strategies for Leber's hereditary optic neuropathy: A current update.

    Science.gov (United States)

    Gueven, Nuri; Faldu, Dharmesh

    2013-11-01

    Leber's hereditary optic neuropathy (LHON) is a rare mitochondrial retinopathy, caused by mutations in subunits of complex I of the respiratory chain, which leads to elevated levels of oxidative stress and an insufficient energy supply. This molecular pathology is thought to be responsible for the dysfunction and eventual apoptotic loss of retinal ganglion cells in the eye, which ultimately results in blindness. Many strategies, ranging from neuroprotectants, antioxidants, anti-apoptotic- and anti-inflammatory compounds have been tested with mixed results. Currently, the most promising compounds are short-chain quinones that have been shown to protect the vision of LHON patients during the early stages of the disease. This commentary gives a brief overview on the current status of tested therapeutics and also addresses future developments such as the use of gene therapy that hopefully will provide safe and efficient therapy options for all LHON patients.

  10. Managing Work and Family: Do Control Strategies Help?

    Science.gov (United States)

    Versey, H. Shellae

    2015-01-01

    How can we effectively manage competing obligations from work and family without becoming overwhelmed? This question inspires the current study by examining control strategies that may facilitate better work-life balance, with a specific focus on the role of lowered aspirations and positive reappraisals, attitudes that underlie adaptive coping…

  11. Managing Work and Family: Do Control Strategies Help?

    Science.gov (United States)

    Versey, H. Shellae

    2015-01-01

    How can we effectively manage competing obligations from work and family without becoming overwhelmed? This question inspires the current study by examining control strategies that may facilitate better work-life balance, with a specific focus on the role of lowered aspirations and positive reappraisals, attitudes that underlie adaptive coping…

  12. Robust Two Degrees-of-freedom Single-current Control Strategy for LCL-type Grid-Connected DG System under Grid-Frequency Fluctuation and Grid-impedance Variation

    DEFF Research Database (Denmark)

    Zhou, Leming; Chen, Yandong; Luo, An

    2016-01-01

    For LCL-type grid-connected distributed generation(DG) system, the grid-frequency fluctuation and grid-impedance variation affect the active/reactive power control accuracy and resonance peak suppression respectively, which would reduce the system robustness. In this paper, a robust two degrees-of-freedom......-state performances. The stability margin and dynamic response of the overall system are analyzed in detail, and the proper parameters are selected without complicated trial. Finally, Simulation and experimental results verify the proposed control and design strategies....

  13. PERFUSION SYSTEM CONTROLLER STRATEGIES DURING AN ECMO SUPPORT

    Directory of Open Access Journals (Sweden)

    M.Dhinakaran

    2014-12-01

    Full Text Available In this work modelling and control of Perfusion system is presented. The Perfusion system simultaneously controls the partial pressures during Extra Corporeal Membrane Oxygenation (ECMO support. The main Problem in ECMO system is exchange of Blood Gases in the Artificial Lung (Oxygenator.It is a highly Nonlinear Process comprising time-varying parameters, and varying time delays, it is currently being controlled manually by trained Perfusionist. The new control strategy implemented here has a feedback linearization routine with time-delay compensation for the Partial pressuresof Oxygen and Carbon dioxide. The controllers were tuned robustly and tested in simulations with a detailed artificial Lung (Oxygenator model in Cardiopulmonary bypass conditions. This Automatic control strategy is proposed to improve the patient’s safety by fast control reference tracking and good disturbance rejection under varying conditions.

  14. Low Activity Waste Feed Process Control Strategy

    Energy Technology Data Exchange (ETDEWEB)

    STAEHR, T.W.

    2000-06-14

    The primary purpose of this document is to describe the overall process control strategy for monitoring and controlling the functions associated with the Phase 1B high-level waste feed delivery. This document provides the basis for process monitoring and control functions and requirements needed throughput the double-shell tank system during Phase 1 high-level waste feed delivery. This document is intended to be used by (1) the developers of the future Process Control Plan and (2) the developers of the monitoring and control system.

  15. Real-time control for long ohmic alternate current discharges

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Ivo S., E-mail: ivoc@ipfn.ist.utl.pt; Duarte, Paulo; Fernandes, Horácio; Valcárcel, Daniel F.; Carvalho, Pedro J.; Silva, Carlos; Duarte, André S.; Neto, André; Sousa, Jorge; Batista, António J.N.; Hekkert, Tiago; Carvalho, Bernardo B.; Gomes, Rui B.

    2014-05-15

    Highlights: • 40 Alternate plasma current (AC) semi-cycles without loss of ionization, more than 1 s of operation. • AC discharges automatic control: feedback loops, time-windows control strategy, goal oriented time-windows and exception handling. • Energy deposition and Carbon radiation evolution during the AC discharges. - Abstract: The ISTTOK tokamak has a long tradition on alternate plasma current (AC) discharges, but the old control system was limiting and lacked full system integration. In order to improve the AC discharges performance the ISTTOK fast control system was updated. This control system developed on site based on the Advanced Telecommunications Computing Architecture (ATCA) standard now integrates the information gathered by all the tokamak real-time diagnostics to produce an accurate observation of the plasma parameters. The real-time actuators were also integrated, allowing a Multiple Input Multiple Output (MIMO) control environment with several synchronization strategies available. The control system software was developed in C++ on top of a Linux system with the Multi-threaded Application Real-Time executor (MARTe) Framework to synchronize the real-time code execution under a 100μs control cycle. In addition, to simplify the discharge programming, a visual Human–Machine Interface (HMI) was also developed using the BaseLib2 libraries included in the MARTe Framework. This paper presents the ISTTOK control system and the optimizations that extended the AC current discharges duration to more than 1 s, corresponding to 40 semi-cycles without apparent degradation of the plasma parameters. This upgrade allows ISTTOK to be used as a low-cost material testing facility with long time exposures to nuclear fusion relevant plasmas, comparable (in duration) with medium size tokamaks.

  16. Driving and control strategies in alternative current machines of permanent magnet with non-sinusoidal flux; Estrategias de acionamento e controle em maquinas CA de ima permanente com fluxo nao senoidal

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, Jose Roberto Boffino de Almeida

    1997-07-01

    The aim of this work is to study and analyze the torque performance of brush less machines with non-sinusoidal distributed magnetic fluxes. The machine type considered is a surface mount permanent magnet brush less machine. Three mathematical models for the machine are considered: the per stator phase, the vectorial and the linear second order speed-voltage models. Machines with different stator windings are compared including the permanent magnet synchronous machines with sinusoidal distributed stator windings. The torque outputs of these machines are obtained considering two kinds of open loop driving systems: one with a six-pulse waveform and other with a sinusoidal waveform. Finally, a vectorial control is proposed for the non-sinusoidal machines. The torque ripple as well the overall performance of non-sinusoidal machines with vectorial control is compared to that of sinusoidal machines. (author)

  17. Consensus on Current Injectable Treatment Strategies in the Asian Face.

    Science.gov (United States)

    Wu, Woffles T L; Liew, Steven; Chan, Henry H; Ho, Wilson W S; Supapannachart, Nantapat; Lee, Hong-Ki; Prasetyo, Adri; Yu, Jonathan Nevin; Rogers, John D

    2016-04-01

    The desire for and use of nonsurgical injectable esthetic facial treatments are increasing in Asia. The structural and anatomical features specific to the Asian face, and differences from Western populations in facial aging, necessitate unique esthetic treatment strategies, but published recommendations and clinical evidence for injectable treatments in Asians are scarce. The Asian Facial Aesthetics Expert Consensus Group met to discuss current practices and consensus opinions on the cosmetic use of botulinum toxin and hyaluronic acid (HA) fillers, alone and in combination, for facial applications in Southeastern and Eastern Asians. Consensus opinions and statements on treatment aims and current practice were developed following discussions regarding pre-meeting and meeting survey outcomes, peer-reviewed literature, and the experts' clinical experience. The indications and patterns of use of injectable treatments vary among patients of different ages, and among Asian countries. The combination use of botulinum toxin and fillers increases as patients age. Treatment aims in Asians and current practice regarding the use of botulinum toxin and HA fillers in the upper, middle, and lower face of patients aged 18 to >55 years are presented. In younger Asian patients, addressing proportion and structural features and deficiencies are important to achieve desired esthetic outcomes. In older patients, maintaining facial structure and volume and addressing lines and folds are essential to reduce the appearance of aging. This paper provides guidance on treatment strategies to address the complex esthetic requirements in Asian patients of all ages. This journal requires that the authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

  18. Nine-Phase Induction Motor Vector Control System Based on the Harmonic Current Closed-Loop Control Strategy%基于谐波电流闭环控制的九相感应电机矢量控制系统

    Institute of Scientific and Technical Information of China (English)

    梅柏杉; 冯江波; 吴迪

    2014-01-01

    采用转子磁链定向矢量控制方法,对九相感应电机矢量控制系统的转矩动静态响应进行了研究。针对应用传统的谐波电流开环控制策略时定子电流谐波含量较大的问题,使用了谐波电流闭环控制策略以抵制各高次谐波对定子电流的影响。以一台九相集中整距绕组感应电机为例,在MATLAB的Simulink工具箱中搭建了完整的九相感应电机矢量控制系统模型。仿真结果表明,系统可以有效抑制定子的谐波电流,且具有较好的动态性能。%Based on the rotor field oriented control method, the dynamic and static torque response of a nine-phase induction motor vector control system was studied. To solve the problem of high harmonic content in the stator current in the conventional harmonic currents open-loops control strategy,the harmonic currents closed-loops control method was used to resist the higher harmonic currents’ s effect on the stator currents . Taking a nine phase concen-trated winding induction motor for example,a complete nine-phase induction motor vector control system model was built in MATLAB/Simulink toolbox. The simulation results show that the system can effectively restrain the stator har-monic current, and has good dynamic performance.

  19. Control Strategy of a Two-Lap Connection Converter

    Institute of Scientific and Technical Information of China (English)

    QUAN Ji-nan; WANG Cong

    2007-01-01

    Two-lap sequential control converters are usually adopted to supply and improve the power factor of input side. The line harmonic damage generated by a sequential control thyristor converter can be serious. To solve this problem and seek an optimum control strategy, we derived the changeable regular of the line-input-current, the fundamental-frequency-current, the harmonic-current-content and the harmonic total distortion ratio of the converter at different firing angles. We obtained relevant data from experiments with a sequential control system of a DC 2.2kW/220V motor. With the example of the operating condition of a DC mine elevator, the harmonic current is two times approximately in sequential control compared to synchronous control when the firing angle of the two converters differs in 30°. At different operating states of a two-lap connection converter, the ideal strategy is an exchange between sequential control and synchronous control, by which we can achieve the complementary goal of improving the power factor and harmonic effect. All analytical conclusions are supported by simulation and experimental results.

  20. 静止坐标系下电流型PWM整流器电流环控制策略研究及其参数设计%A Novel Control Strategy and Its Parameter Design of the Current-loop in a Stationary Frame for Current-source PWM Rectifiers

    Institute of Scientific and Technical Information of China (English)

    郭强; 刘和平; 彭东林; 刘平; 张毅

    2014-01-01

    By analyzing the mathematical model of the three-phase pulse width modulation (PWM) current-source rectifier (CSR) in a stationary reference frame based on the instantaneous power theory, a voltage-oriented CSR power control strategy was proposed. As an alternative approach for active damping, the proportional capacitor-voltage feedback was used to damp the inductor-capacitor filter (LC) resonance. The system transfer function of the inner-current loop was analyzed using the frequency response method. In order to improve the limitations on dynamic response and stability of the controller,a new cascaded lag compensation method for inner-current loop was presented. The impacts of proportional resonant (PR) controller and its parameters in the inner-current loop were analyzed. Then, the parameter values of the controller were chosen according to the performance indicators. Stability against the filter inductance variation was studied by means of the root locus analysis, the correlation between active damping feedback gain and system robustness had been established. Finally, the controllers were discretized with the Tustin transformation. Simulations of a 60 kVA laboratory prototype shows that the proposed control method is able to generate excellent dynamic and steady-state performances, improve power factor, and reduce the input-current distortion.%通过分析三相脉宽调制电流型整流器(current source rectifier,CSR)在两相静止坐标系中的数学模型,利用瞬时功率理论建立电压定向的CSR功率控制策略。为了有效抑制整流器输入侧LC滤波器产生的并联谐振,文中引入电容电压反馈有源阻尼控制环路。采用频域法对电流内环开环传递函数进行研究,针对静置坐标系下电流内环在动态响应和稳定性方面的限制,提出电流内环级联滞后补偿控制方法。详细研究电流内环比例谐振控制器及各参数对其性能的影响,并根据性能指标要求确

  1. Longitudinal Control Strategy for Vehicle Adaptive Cruise Control Systems

    Institute of Scientific and Technical Information of China (English)

    WU Li-jun; LIU Zhao-du; MA Yue-feng

    2007-01-01

    A new longitudinal control strategy for vehicle adaptive cruise control (ACC) systems is presented.The running relationship between the ACC vehicle and the detected target vehicle is described by the relative velocity and the deviation between the actual headway distance and the prescribed safety distance.Based on this,two state space models are built and the linear quadratic optimal control theory is used to yield desired velocity for the ACC-equipped vehicle when with the target vehicle detected.By switching among four control modes,the desired velocity profile is designed to deal with different running situations.A velocity controller,which includes a PID controller for throttle openness and a neural network controller for brake application,is developed to achieve the desired velocity profile.The proposed control strategy is applied to a non-linear vehicle model in a simulation environment and is shown to provide the ACC vehicle comfortable ride and satisfying safety.

  2. [Current operative techniques and strategies in endocrine surgery].

    Science.gov (United States)

    Gürtler, Thomas; Weber, Markus

    2011-06-01

    Technical advances and focusing on subsets modified endocrine surgery in the last ten years tremendously. There is on one side a clear trend towards minimal invasive approaches, first of all in the surgery of the adrenal glands, where the transperitoneal or retroperitoneal laparoscopic adrenalectomy has become the gold standard for tumors up to a size of 10 cm in diameter. But also in pancreatic endocrine surgery for small tumors localized in the pancreas tail and up to a certain extend in thyroid and parathyroid surgery, laparoscopic or video assisted techniques are used. On the other side more precise techniques allow a more complete and radical removal of endocrine tissue, especially in thyroid surgery. This article presents a summary of current operative techniques and strategies in endocrine surgery.

  3. On Control Strategies for Responsive Architectural Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Parigi, Dario

    2012-01-01

    The present paper considers control of responsive architectural structures for improvement of structural performance by recognizing changes in their environments and loads, adapting to meet goals, and using past events to improve future performance or maintain serviceability. The general scope...... of the paper is to discuss control strategies for responsive architectural structures, particularly reconfigurable architectural structures which can transform body shape, i.e. a transformation into more than one or two different shape alternatives....

  4. Shopping for acid rain control strategies

    Energy Technology Data Exchange (ETDEWEB)

    Greenberger, L.S.

    1992-01-15

    A utility manager trying to pick a compliance strategy today probably feels a lot like a child in a toy store: So many from which to choose - and so little time. This article examines the technologies available and which technologies utilities are likely to use to control SO[sub 2] emissions.

  5. Main Strategies for Autonomous Robotic Controller Design

    OpenAIRE

    Paterega, I.

    2011-01-01

    This review gives an overall introduction to the artificial evolution mechanism. It presents the main strategies for robotic controller design. It gives a review of the pertinent literature, focusing on approaches that use neural networks, evolutionary computing, and fuzzy logic. Various applications of artificial evolution in robotics are surveyed and classified.

  6. Reimbursed Price of Orphan Drugs: Current Strategies and Potential Improvements.

    Science.gov (United States)

    Mincarone, Pierpaolo; Leo, Carlo Giacomo; Sabina, Saverio; Sarriá-Santamera, Antonio; Taruscio, Domenica; Serrano-Aguilar, Pedro Guillermo; Kanavos, Panos

    2017-01-01

    The pricing and reimbursement policies for pharmaceuticals are relevant to balance timely and equitable access for all patients, financial sustainability, and reward for valuable innovation. The proliferation of high-cost specialty medicines is particularly true in rare diseases (RDs) where the pricing mechanism is characterised by a lack of transparency. This work provides an overall picture of current strategies for the definition of the reimbursed prices of orphan drugs (ODs) and highlights some potential improvements. Current strategies and suggestions are presented along 4 dimensions: (1) comprehensive value assessment, (2) early dialogs among relevant stakeholders, (3) innovative reimbursement approaches, and (4) societal participation in producing ODs. Comprehensive value assessment could be achieved by clarifying the approach of distributive justice to adopt, ensuring a representative participation of stakeholders, and with a broad consideration of value-bearing factors. With respect to early dialogs, cross-border cooperation can be determinant to companies and agencies. The cost-benefit ratio of early dialogs needs to be demonstrated and the "regulatory capture" effect should be monitored. Innovative reimbursement approaches were developed to balance the need for evidence-based decisions with the timely access to innovative drugs. The societal participation in producing ODs needs to be recognised in a collaborating framework where adaptive agreements can be developed with mutual satisfaction. Such agreements could also impact on coverage and reimbursement decisions as additional elements for the determination of a comprehensive societal value of ODs. Further research is needed to investigate the highlighted open challenges so that RDs will not remain, in practical terms, orphan diseases. © 2017 S. Karger AG, Basel.

  7. Enhanced Power Quality and Minimized Peak Current Control in An Inverter based Microgrid under Unbalanced Grid Faults

    DEFF Research Database (Denmark)

    Liu, Wenzhao; Guo, Xiaoqiang; Sulligoi, Giorgio

    2016-01-01

    ride through control. In order to solve this problem, a novel control strategy is proposed to enhance the output current quality while mitigating the active and reactive output power oscillations. Moreover, a simple current-limited control strategy can be achieved without the necessity of the voltage....../current positive/negative sequence extraction. Finally, the simulation tests of the conventional and proposed control solutions are carried out. The results verify the effectiveness of the proposed strategy....

  8. Oligometastatic non-small-cell lung cancer: current treatment strategies

    Directory of Open Access Journals (Sweden)

    Richard PJ

    2016-11-01

    Full Text Available Patrick J Richard, Ramesh Rengan Department of Radiation Oncology, University of Washington, Seattle, WA, USA Abstract: The oligometastatic disease theory was initially described in 1995 by Hellman and Weichselbaum. Since then, much work has been performed to investigate its existence in many solid tumors. This has led to subclassifications of stage IV cancer, which could redefine our treatment approaches and the therapeutic outcomes for this historically “incurable” entity. With a high incidence of stage IV disease, non-small-cell lung cancer (NSCLC remains a difficult cancer to treat and cure. Recent work has proven the existence of an oligometastatic state in NSCLC in terms of properly selecting patients who may benefit from aggressive therapy and experience long-term overall survival. This review discusses the current treatment approaches used in oligometastatic NSCLC and provides the evidence and rationale for each approach. The prognostic factors of many trials are discussed, which can be used to properly select patients for aggressive treatment regimens. Future advances in both molecular profiling of NSCLC to find targetable mutations and investigating patient selection may increase the number of patients diagnosed with oligometastatic NSCLC. As this disease entity increases, it is of utmost importance for oncologists treating NSCLC to be aware of the current treatment strategies that exist and the potential advantages/disadvantages of each. Keywords: oligometastatic, non-small-cell lung cancer, oligoprogressive, treatment

  9. Managing Air Quality - Control Strategies to Achieve Air Pollution Reduction

    Science.gov (United States)

    Considerations in designing an effective control strategy related to air quality, controlling pollution sources, need for regional or national controls, steps to developing a control strategy, and additional EPA resources.

  10. Novel strategies for control of fermentation processes

    DEFF Research Database (Denmark)

    Mears, Lisa

    There is increasing interest in applying more advanced control strategies to biological processes in order to optimise the operation of these complex systems. In the past years, the major increases in product titre have been achieved mainly by genetic engineering approaches, which has lead......? In order to develop control strategies a significant effort must be invested into developing process models and establishing process understanding. Both data-driven modelling and mechanistic modelling approaches are considered in this work. Firstly, multivariate analysis is applied to production scale data...... (2012). This model describes the fungal processes operated in the fermentation pilot plant at Novozymes A/S. This model is investigated using uncertainty analysis methods in order to as-sess the applicability to control applications. A mechanistic model approach is desirable, as it is a predictive...

  11. New pheromones and insect control strategies.

    Science.gov (United States)

    Reddy, Gadi V P; Guerrero, Angel

    2010-01-01

    A survey of the new environmentally safe strategies used for insect control is presented. The survey includes mating disruption, pheromone antagonists as chemical communication inhibitors, pheromones and plant-based volatiles, attractant-and-kill, and push-pull strategies. Important successes have been obtained, particularly in mating disruption with significant reduction in pesticide use in low to moderate pest infestations. One important factor of concern is the high cost of semiochemicals and formulations containing them in comparison to the conventional insecticide treatments, and a combined effort by scientists, producers, and farmers should be made to reduce the cost of application of these semiochemicals. Copyright © 2010 Elsevier Inc. All rights reserved.

  12. Sliding Mode Control of Induction Motor Phase Currents

    DEFF Research Database (Denmark)

    Hansen, R.B.; Hattel, T.; Bork, J

    1995-01-01

    Sliding mode control of induction motor phase currents are investigated through development of two control concepts.......Sliding mode control of induction motor phase currents are investigated through development of two control concepts....

  13. Sliding Mode Control of Induction Motor Phase Currents

    DEFF Research Database (Denmark)

    Hansen, R.B.; Hattel, T.; Bork, J

    1995-01-01

    Sliding mode control of induction motor phase currents are investigated through development of two control concepts.......Sliding mode control of induction motor phase currents are investigated through development of two control concepts....

  14. 苏州市东山镇池塘养蟹面源污染现状及控制%Current status and control strategies of non-point source pollution from pond aquaculture in Dongshan town of Suzhou

    Institute of Scientific and Technical Information of China (English)

    宋学宏; 郭培红; 孙丽萍; 朱江

    2011-01-01

    结合全国污染源普查活动,以苏州市养殖老区东山镇养殖池塘为典型,调查其现行养殖模式、经济效益、养殖污染状况.调查结果显示,东山镇现有养殖面积为2253.33hm2,主养品种为河蟹.1个养殖周期中,养殖池塘通过沟渠排入外界的TN、TP含量分别平均为21.25kg/hm2、2.34kg/hm2;密度为9000只/hm2的低密度养殖池外排的TN含量为16.79kg/hm2,而无TP排出.分析苏州地区池塘养殖产生水环境污染的主要原因,从池塘管理体制改革、科学生态养殖技术及养殖尾水处理等方面探讨池塘养殖污水零排放技术,为苏州市养殖业面源污染的控制提供对策和措施.%Combining with national census of pollution sources and using large-scale pond aquaculture in Dongshan town in Suzhou as a case study, the current cultural modes, economic benefits, and aquaculture pollution were surveyed. The results showed that there were 2 253.33 hm2 of aquaculture in Dongshan town, and the Chinese mitten crab was the main specie. In a single aquaculture period, the discharged total nitrogen (TN) and total phosphorus (TP) from pounds to outside through canals and ditches were on average 21.25 kg/hm2 and 2.34 kg/hm2 respectively. However, in a lowdensity crab raising pond of 9000 ind/hm2, the discharged TN was 16.79 kg/hm2, and no TP was found to be discharged.Based on the case study, the main reasons for the water environment pollution by pond aquaculture were analyzed, and the zero discharge technologies for the waste water of pond aquaculture were discussed from aspects of the management system reform for pond, the scientific and ecological raising technique, and the aquaculture wastewater treatment. The possible strategies and countermeasures for controlling the aquacultural non-point source pollution in Suzhou were also provided.

  15. The push-pull strategy for citrus psyllid control.

    Science.gov (United States)

    Yan, Huaxue; Zeng, Jiwu; Zhong, Guangyan

    2015-07-01

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the only natural vector of Candidatus Liberibacter asiaticus that causes citrus huanglongbing (HLB), a most destructive disease of citrus. Currently, no remedial therapy exists for the disease, and so effective control of ACP is very important in curbing the transmission of the disease. The push-pull strategy should be thoroughly explored as an approach to ACP management. This mini-review summarises the current progress towards more effective repellent and attractant chemicals through investigating known repellent and attractive plants. Interactions between ACP and its host plants are also addressed, with emphasis on the possible involvement of the host biochemicals in attracting the insect. Potential ways to increase the effectiveness of the pull-push strategy are briefly discussed. It is expected that the pull-push strategy will be gradually developed following more extensive research.

  16. Environmental Process Control: Strategies and Implementation

    Directory of Open Access Journals (Sweden)

    Jurgis Staniskis

    2006-04-01

    Full Text Available The structure and mathematical presentation of the optimal strategy for environmental process control is presented. This approach covers a wide variety of control systems, which have been constructed and analysed at the Institute of Environmental Engineering during the last fifteen years. Special attention is paid to the preventive environmental control and its tools: pollution prevention, life cycle assessment. The implementation results of preventive environmental control from more than 150 companies are presented in the paper.The investigations on water quality control issues are evaluated from the point of view of the interface between physico-ecological and socio-economical systems and decision support system based on river water quality model is suggested.

  17. Night ventilation control strategies in office buildings

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhaojun; Yi, Lingli; Gao, Fusheng [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China)

    2009-10-15

    In moderate climates night ventilation is an effective and energy-efficient approach to improve the indoor thermal environment for office buildings during the summer months, especially for heavyweight construction. However, is night ventilation a suitable strategy for office buildings with lightweight construction located in cold climates? In order to answer this question, the whole energy-consumption analysis software EnergyPlus was used to simulate the indoor thermal environment and energy consumption in typical office buildings with night mechanical ventilation in three cities in northern China. The summer outdoor climate data was analyzed, and three typical design days were chosen. The most important factors influencing night ventilation performance such as ventilation rates, ventilation duration, building mass and climatic conditions were evaluated. When night ventilation operation time is closer to active cooling time, the efficiency of night ventilation is higher. With night ventilation rate of 10 ach, the mean radiant temperature of the indoor surface decreased by up to 3.9 C. The longer the duration of operation, the more efficient the night ventilation strategy becomes. The control strategies for three locations are given in the paper. Based on the optimized strategies, the operation consumption and fees are calculated. The results show that more energy is saved in office buildings cooled by a night ventilation system in northern China than ones that do not employ this strategy. (author)

  18. 磁悬浮风力发电机零偏置电流控制策略研究%Control strategy with zero-bias current for magnetic levitation wind power generator

    Institute of Scientific and Technical Information of China (English)

    王晓; 谢振宇; 周红凯

    2014-01-01

    建立了5自由度磁悬浮轴承支撑的垂直轴风力发电机转子试验系统,研制了零偏置电流模拟控制器,通过试验方法研究了该控制器对系统动态性能的影响。结果表明,零偏置电流控制方式在显著降低磁悬浮轴承电能损耗的同时仍然能够保证垂直轴风力发电机转子系统稳定运行。%The setup of a vertical axis wind power generator rotor system with 5-DOF supported with active magnetic bearings was built.A zero-bias current analog controller was also developed.The influence of the controller on the dynamic performance of the system was investigated with the test method.The results showed that the zero-bias current analog controller can be used to reduce power loss of active magnetic bearings obviously,and also to guarantee safe and stable operation of the system at the same time.

  19. Sports-related concussions: diagnosis, complications, and current management strategies.

    Science.gov (United States)

    Hobbs, Jonathan G; Young, Jacob S; Bailes, Julian E

    2016-04-01

    Sports-related concussions (SRCs) are traumatic events that affect up to 3.8 million athletes per year. The initial diagnosis and management is often instituted on the field of play by coaches, athletic trainers, and team physicians. SRCs are usually transient episodes of neurological dysfunction following a traumatic impact, with most symptoms resolving in 7-10 days; however, a small percentage of patients will suffer protracted symptoms for years after the event and may develop chronic neurodegenerative disease. Rarely, SRCs are associated with complications, such as skull fractures, epidural or subdural hematomas, and edema requiring neurosurgical evaluation. Current standards of care are based on a paradigm of rest and gradual return to play, with decisions driven by subjective and objective information gleaned from a detailed history and physical examination. Advanced imaging techniques such as functional MRI, and detailed understanding of the complex pathophysiological process underlying SRCs and how they affect the athletes acutely and long-term, may change the way physicians treat athletes who suffer a concussion. It is hoped that these advances will allow a more accurate assessment of when an athlete is truly safe to return to play, decreasing the risk of secondary impact injuries, and provide avenues for therapeutic strategies targeting the complex biochemical cascade that results from a traumatic injury to the brain.

  20. Current Research Therapeutic Strategies for Alzheimer's Disease Treatment

    Science.gov (United States)

    Folch, Jaume; Petrov, Dmitry; Ettcheto, Miren; Abad, Sonia; Sánchez-López, Elena; García, M. Luisa; Olloquequi, Jordi; Beas-Zarate, Carlos; Auladell, Carme; Camins, Antoni

    2016-01-01

    Alzheimer's disease (AD) currently presents one of the biggest healthcare issues in the developed countries. There is no effective treatment capable of slowing down disease progression. In recent years the main focus of research on novel pharmacotherapies was based on the amyloidogenic hypothesis of AD, which posits that the beta amyloid (Aβ) peptide is chiefly responsible for cognitive impairment and neuronal death. The goal of such treatments is (a) to reduce Aβ production through the inhibition of β and γ secretase enzymes and (b) to promote dissolution of existing cerebral Aβ plaques. However, this approach has proven to be only modestly effective. Recent studies suggest an alternative strategy centred on the inhibition of the downstream Aβ signalling, particularly at the synapse. Aβ oligomers may cause aberrant N-methyl-D-aspartate receptor (NMDAR) activation postsynaptically by forming complexes with the cell-surface prion protein (PrPC). PrPC is enriched at the neuronal postsynaptic density, where it interacts with Fyn tyrosine kinase. Fyn activation occurs when Aβ is bound to PrPC-Fyn complex. Fyn causes tyrosine phosphorylation of the NR2B subunit of metabotropic glutamate receptor 5 (mGluR5). Fyn kinase blockers masitinib and saracatinib have proven to be efficacious in treating AD symptoms in experimental mouse models of the disease. PMID:26881137

  1. Current Research Therapeutic Strategies for Alzheimer’s Disease Treatment

    Directory of Open Access Journals (Sweden)

    Jaume Folch

    2016-01-01

    Full Text Available Alzheimer’s disease (AD currently presents one of the biggest healthcare issues in the developed countries. There is no effective treatment capable of slowing down disease progression. In recent years the main focus of research on novel pharmacotherapies was based on the amyloidogenic hypothesis of AD, which posits that the beta amyloid (Aβ peptide is chiefly responsible for cognitive impairment and neuronal death. The goal of such treatments is (a to reduce Aβ production through the inhibition of β and γ secretase enzymes and (b to promote dissolution of existing cerebral Aβ plaques. However, this approach has proven to be only modestly effective. Recent studies suggest an alternative strategy centred on the inhibition of the downstream Aβ signalling, particularly at the synapse. Aβ oligomers may cause aberrant N-methyl-D-aspartate receptor (NMDAR activation postsynaptically by forming complexes with the cell-surface prion protein (PrPC. PrPC is enriched at the neuronal postsynaptic density, where it interacts with Fyn tyrosine kinase. Fyn activation occurs when Aβ is bound to PrPC-Fyn complex. Fyn causes tyrosine phosphorylation of the NR2B subunit of metabotropic glutamate receptor 5 (mGluR5. Fyn kinase blockers masitinib and saracatinib have proven to be efficacious in treating AD symptoms in experimental mouse models of the disease.

  2. Traumatic Brain Injury: Current Treatment Strategies and Future Endeavors.

    Science.gov (United States)

    Galgano, Michael; Toshkezi, Gentian; Qiu, Xuecheng; Russell, Thomas; Chin, Lawrence; Zhao, Li-Ru

    2016-11-22

    Traumatic brain injury presents in various forms ranging from mild alterations of consciousness to an unrelenting comatose state and death. In the most severe form of traumatic brain injury, the entirety of the brain is affected by a diffuse type of injury and swelling. Treatment modalities vary extensively based on the severity of the injury and range from daily cognitive therapy sessions to radical surgery such as bilateral decompressive craniectomies. Guidelines have been set forth regarding the optimal management of traumatic brain injury, but they must be taken in context of the situation and cannot be used in every individual circumstance. In this review article, we have summarized the current status of treatment for traumatic brain injury in both clinical practice and basic research. We have put forth a brief overview of the various subtypes of traumatic injuries, optimal medical management, as well as both the non-invasive and invasive monitoring modalities, in addition to the surgical interventions necessary in particular instances. We have overviewed the main achievements in searching for therapeutic strategies of traumatic brain injury in basic science. We have also discussed the future direction for developing traumatic brain injury treatment from an experimental perspective.

  3. Soil contamination in China: current status and mitigation strategies.

    Science.gov (United States)

    Zhao, Fang-Jie; Ma, Yibing; Zhu, Yong-Guan; Tang, Zhong; McGrath, Steve P

    2015-01-20

    China faces great challenges in protecting its soil from contamination caused by rapid industrialization and urbanization over the last three decades. Recent nationwide surveys show that 16% of the soil samples, 19% for the agricultural soils, are contaminated based on China’s soil environmental quality limits, mainly with heavy metals and metalloids. Comparisons with other regions of the world show that the current status of soil contamination, based on the total contaminant concentrations, is not worse in China. However, the concentrations of some heavy metals in Chinese soils appear to be increasing at much greater rates. Exceedance of the contaminant limits in food crops is widespread in some areas, especially southern China, due to elevated inputs of contaminants, acidic nature of the soil and crop species or cultivars prone to heavy metal accumulation. Minimizing the transfer of contaminants from soil to the food chain is a top priority. A number of options are proposed, including identification of the sources of contaminants to agricultural systems, minimization of contaminant inputs, reduction of heavy metal phytoavailability in soil with liming or other immobilizing materials, selection and breeding of low accumulating crop cultivars, adoption of appropriate water and fertilizer management, bioremediation, and change of land use to grow nonfood crops. Implementation of these strategies requires not only technological advances, but also social-economic evaluation and effective enforcement of environmental protection law.

  4. Prostate biopsy strategies: current state of the art.

    Science.gov (United States)

    Mian, Badar M

    2004-05-01

    Prostate-specific antigen testing and prostate biopsy have revolutionized our ability to detect prostate cancer at an early stage. The transrectal ultrasound-guided biopsy procedure has undergone a number of modifications over the past 10 years to meet our goal of early detection of cancer at a curable stage. Biopsy schemes have evolved from lesion-directed biopsies to systematic mapping of the peripheral zone of the prostate, which harbors almost all of the significant tumor foci. An increase in the number of biopsy cores from 6 to 10 (or 12) has resulted in a significant improvement in the detection of clinically localized cancer, without any appreciable increase in the number of indolent cancers. Current biopsy schemes also have enhanced our ability to determine the true prognostic value of pathologic lesions such as high-grade prostatic intraepithelial neoplasia and atypical small acinar proliferation which have been associated with cancer detection in repeat biopsies. I discuss the rationale behind, and the outcomes of, various biopsy strategies. More than 15 years after PSA testing was popularized for early detection, a number of men are presenting for evaluation regarding repeat prostate biopsy for various clinical indications. The indications, biopsy scheme, and cancer detection rates for repeat prostate biopsy are discussed in detail.

  5. Current intervention strategies for the microbial safety of sprouts.

    Science.gov (United States)

    Sikin, Adi Md; Zoellner, Claire; Rizvi, Syed S H

    2013-12-01

    Sprouts have gained popularity worldwide due to their nutritional values and health benefits. The fact that their consumption has been associated with numerous outbreaks of foodborne illness threatens the $250 million market that this industry has established in the United States. Therefore, sprout manufacturers have utilized the U.S. Food and Drug Administration recommended application of 20,000 ppm of calcium hypochlorite solution to seeds before germination as a preventative method. Concentrations of up to 200 ppm of chlorine wash are also commonly used on sprouts. However, chlorine-based treatment achieves on average only 1- to 3-log reductions in bacteria and is associated with negative health and environmental issues. The search for alternative strategies has been widespread, involving chemical, biological, physical, and hurdle processes that can achieve up to 7-log reductions in bacteria in some cases. The compilation here of the current scientific data related to these techniques is used to compare their efficacy for ensuring the microbial safety of sprouts and their practicality for commercial producers. Of specific importance for alternative seed and sprout treatments is maintaining the industry-accepted germination rate of 95% and the sensorial attributes of the final product. This review provides an evaluation of suggested decontamination technologies for seeds and sprouts before, during, and after germination and concludes that thermal inactivation of seeds and irradiation of sprouts are the most practical stand-alone microbial safety interventions for sprout production.

  6. A Computationally Efficient Aggregation Optimization Strategy of Model Predictive Control

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Model Predictive Control (MPC) is a popular technique and has been successfully used in various industrial applications. However, the big drawback of MPC involved in the formidable on-line computational effort limits its applicability to relatively slow and/or small processes with a moderate number of inputs. This paper develops an aggregation optimization strategy for MPC that can improve the computational efficiency of MPC. For the regulation problem, an input decaying aggregation optimization algorithm is presented by aggregating all the original optimized variables on control horizon with the decaying sequence in respect of the current control action.

  7. Decentralized Coordinated Control Strategy of Islanded Microgrids

    DEFF Research Database (Denmark)

    Wu, Dan

    as grid voltage/frequency regulation. In order to enhance the reliability of overall islanded Microgrid operation, basic functions of coordinated control which taking into account the state of charge (SoC) limitation and power availability of renewable energy sources is implemented in a distributed level...... control strategies in this thesis, in order to promote the decentralization of the overall system. Especially the consensus algorithm based secondary level is investigated in the thesis in order to simplify the communication configuration which only flood information through the neighboring units...

  8. Modelling and Control Design of Unified Power Flow Controller for Various Control Strategies

    Directory of Open Access Journals (Sweden)

    T. Nireekshana

    2010-11-01

    Full Text Available Unified Power Flow Controller (UPFC is used to control the power flow in the transmission systems by controlling the impedance, voltage magnitude and phase angle. This controller offers advantages in terms of static and dynamic operation of the power system. It also brings in new challenges in power electronics and power system design. The basic structure of the UPFC consists of two voltage source inverter (VSI; where one converter is connected in parallel to the transmission line while the other is in series with the transmission line. The aim of the paper is to develop a control strategy for UPFC, modeling UPFC using MATLAB/SIMULINK and to analyze the control strategy to use the series voltage injection and shunt current injection for UPFC control. To simplify the design procedure we carry out the design for the series and shunt branches separately.In each case, a simple equivalent circuit represents the external system. The design has to be validated when the various subsystems are integrated.

  9. Some thoughts on separation control strategies

    Indian Academy of Sciences (India)

    P R Viswanath

    2007-02-01

    Separation control has received considerable emphasis in literature both owing to fundamental flow physics and technological applications. Flow separation generally leads to increased energy losses, instability and so on, and its control is essential to improve aerodynamic performance. Here a brief review is presented of three broad strategies for separation control: these include methods that involve energization of the boundary layer upstream of separation, those that involve altering the bubble flow or dead air zone, and those that may influence the shear layer reattachment directly. Examples from recent research in our laboratories are reviewed and it is suggested that direct manipulation of the reattachment process could lead to effective control/management.

  10. Predictive current control of permanent magnet synchronous motor based on linear active disturbance rejection control

    Science.gov (United States)

    Li, Kunpeng

    2017-01-01

    The compatibility problem between rapidity and overshooting in the traditional predictive current control structure is inevitable and difficult to solve by reason of using PI controller. A novel predictive current control (PCC) algorithm for permanent magnet synchronous motor (PMSM) based on linear active disturbance rejection control (LADRC) is presented in this paper. In order to displace PI controller, the LADRC strategy which consisted of linear state error feedback (LSEF) control algorithm and linear extended state observer (LESO), is designed based on the mathematic model of PMSM. The purpose of LSEF is to make sure fast response to load mutation and system uncertainties, and LESO is designed to estimate the uncertain disturbances. The principal structures of the proposed system are speed outer loop based on LADRC and current inner loop based on predictive current control. Especially, the instruction value of qaxis current in inner loop is derived from the control quantity which is designed in speed outer loop. The simulation is carried out in Matlab/Simulink software, and the results illustrate that the dynamic and static performances of proposed system are satisfied. Moreover the robust against model parameters mismatch is enhanced obviously.

  11. Old Disease and New Challenges: Major Obstacles of Current Strategies in the Prevention of Pertussis

    Directory of Open Access Journals (Sweden)

    Iraj Sedighi

    2016-06-01

    Full Text Available Context Universal immunization against Bordetella pertussis has partially controlled the burden of the disease and its transmission. However, according to recent data, the epidemiology of this vaccine-preventable disease has changed. Now, younger infants, adolescents, and adults are at greater risk of infection. This article has studied the interaction between the various factors involved in the changing epidemiology of pertussis and the major obstacles faced by the current strategies in its prevention. Evidence Acquisition In this narrative review, the most recently published sources of information on pertussis control measures, consisting of textbooks and articles, have been reviewed. We focused on the more recent data about the changing epidemiology or pertussis in Scopus through the use of the MeSH-term words [pertussis] or [whooping cough] and [epidemiology] or [outbreak] or [resurgence], but our search was not restricted to this particular strategy; we also tried to find all of the most recent available data in the general field through other means. Results Primary and booster doses of the pertussis vaccine seem to partially control transmission of the disease, but despite the different preventive strategies available, pertussis continues to cause mortality and morbidity among high-risk groups. Conclusions Adding booster doses of acellular pertussis vaccine to the current national immunization practices with whole-cell vaccines for young adults and pregnant women seems to be a good option for controlling mortality and morbidity among high-risk groups such as very young infants.

  12. Old Disease and New Challenges: Major Obstacles of Current Strategies in the Prevention of Pertussis

    Science.gov (United States)

    Sedighi, Iraj; Karimi, Abdollah; Amanati, Ali

    2016-01-01

    Context Universal immunization against Bordetella pertussis has partially controlled the burden of the disease and its transmission. However, according to recent data, the epidemiology of this vaccine-preventable disease has changed. Now, younger infants, adolescents, and adults are at greater risk of infection. This article has studied the interaction between the various factors involved in the changing epidemiology of pertussis and the major obstacles faced by the current strategies in its prevention. Evidence Acquisition In this narrative review, the most recently published sources of information on pertussis control measures, consisting of textbooks and articles, have been reviewed. We focused on the more recent data about the changing epidemiology or pertussis in Scopus through the use of the MeSH-term words [pertussis] or [whooping cough] and [epidemiology] or [outbreak] or [resurgence], but our search was not restricted to this particular strategy; we also tried to find all of the most recent available data in the general field through other means. Results Primary and booster doses of the pertussis vaccine seem to partially control transmission of the disease, but despite the different preventive strategies available, pertussis continues to cause mortality and morbidity among high-risk groups. Conclusions Adding booster doses of acellular pertussis vaccine to the current national immunization practices with whole-cell vaccines for young adults and pregnant women seems to be a good option for controlling mortality and morbidity among high-risk groups such as very young infants. PMID:27729960

  13. Current strategies for the prevention of breast cancer

    Directory of Open Access Journals (Sweden)

    Advani P

    2014-05-01

    Full Text Available Pooja Advani, Alvaro Moreno-AspitiaDepartment of Hematology and Oncology, Mayo Clinic, Jacksonville, FL, USAAbstract: Due to the high incidence of breast cancer in the United States, optimal strategies for its prevention are imperative. This entails identification of women who are at an increased risk for breast cancer and an integrative approach that includes effective screening methods as well as nutritional, pharmacologic, and surgical management. Several breast cancer risk-assessment tools, such as the Gail and Claus models, can help clinicians determine the quantitative risk of breast cancer. The role of selective estrogen receptor modulators, such as tamoxifen and raloxifene, for the prevention of breast cancer has been well established. Several other agents, such as aromatase inhibitors, are currently being investigated. The potential adverse effects of these chemopreventive agents, which include an impact on the quality of life, must be discussed with the patient before deciding on this approach. Additionally, breast cancer risk factors have been identified over the years; some of them are modifiable, but others are not. Although there is no conclusive evidence to suggest the protective role of specific dietary components, alcohol consumption and obesity are associated with an increased breast cancer risk; thus lifestyle changes can lead to a lower risk of developing breast cancer. Surgical approaches, including bilateral risk-reduction mastectomy and salpingo-oophorectomy, are usually limited to women with a hereditary predisposition to development of breast cancer. The objective of this review is to summarize the various approaches directed at reducing the incidence of breast cancer.Keywords: chemoprevention, tamoxifen, raloxifene, prophylactic surgery

  14. Circuit Controls Turn-On Current

    Science.gov (United States)

    Holmes, K. G.

    1972-01-01

    Single choke used in primary circuit with diode arrangement, maintaining dc current flow through choke and setting up a unidirectional magnetic field, limits turn-on current of transformer-rectifier power supply. Technique reduces number and weight of components and minimizes effect of initial inrush surge current on source.

  15. Controlling strategy of dormant Mycobacterium tuberculosis

    Institute of Scientific and Technical Information of China (English)

    Gan Yiling; Guo Shuliang

    2014-01-01

    Objective This study aimed to review the available literatures on control of latent tuberculosis (TB) infection and propose a new control strategy to shorten the course of TB chemotherapy.Data sources The data used in this review were mainly obtained from articles listed in PubMed.The search terms were "therapy (treatment) of tuberculosis," "therapy (treatment) of latent TB infection," and "vaccine of TB."Study selection Articles regarding treatment and vaccine of TB were selected and reviewed.Results The most crucial reason causing the prolonged course of TB chemotherapy is the dormant state of Mycobacterium tuberculosis (M.tuberculosis).Nevertheless,there are,to date,no effective drugs that can directly kill the dormant cells of M.tuberculosis in clinical therapy.In accordance with the growth cycle of dormant M.tuberculosis in the body,the methods for controlling dormant M.tuberculosis include direct killing with drugs,prevention of dormant M.tuberculosis resuscitation with vaccines,and resuscitating dormant M.tuberculosis with preparations or drugs and then thoroughly killing these resuscitated M.tuberculosis by using anti-TB therapy.Conclusions The comprehensive analysis of the above three methods suggests that the drugs directly killing dormant cells are in clinical trials,TMC207 is the most beneficial for controlling TB.Because the side effect of vaccines is less and their action period is long,prevention of dormant cells resuscitation with vaccines is promising.The last control method makes it probable that when a huge number of active cells of M.tuberculosis have been killed and eradicated after 1-month short chemotherapy,only a strong short-term subsequent chemotherapy can completely kill and eradicate the remaining M.tuberculosis.This control strategy is expected to significantly shorten the course of TB chemotherapy and bring a new change and breakthrough in TB treatment.

  16. Drug Control: Observations on Elements of the Federal Drug Control Strategy. Report to Congressional Requesters.

    Science.gov (United States)

    General Accounting Office, Washington, DC. General Government Div.

    Although the United States government invests vast sums of money in the war on drugs, the availability of drugs and the number of persons using illegal drugs are still serious problems. Information that Congress can use in improving drug control strategies is provided here. Some of the report's highlights include current research on promising…

  17. Active steering control strategy for articulated vehicles

    Institute of Scientific and Technical Information of China (English)

    Kyong-il KIM; Hsin GUAN; Bo WANG; Rui GUO; Fan LIANG

    2016-01-01

    To improve maneuverability and stability of articulated vehicles, we design an active steering controller, including tractor and trailer controllers, based on linear quadratic regulator (LQR) theory. First, a three-degree-of-freedom (3-DOF) model of the tractor-trailer with steered trailer axles is built. The simulated annealing particle swarm optimization (SAPSO) algorithm is applied to identify the key parameters of the model under specified vehicle speed and steering wheel angle. Thus, the key pa-rameters of the simplified model can be obtained according to the vehicle conditions using an online look-up table and interpola-tion. Simulation results show that vehicle parameter outputs of the simplified model and TruckSim agree well, thus providing the ideal reference yaw rate for the controller. Then the active steering controller of the tractor and trailer based on LQR is designed to follow the desired yaw rate and minimize their side-slip angle of the center of gravity (CG) at the same time. Finally, simulation tests at both low speed and high speed are conducted based on the TruckSim-Simulink program. The results show significant effects on the active steering controller on improving maneuverability at low speed and lateral stability at high speed for the articulated vehicle. The control strategy is applicable for steering not only along gentle curves but also along sharp curves.

  18. Control strategies for aircraft airframe noise reduction

    Institute of Scientific and Technical Information of China (English)

    Li Yong; Wang Xunnian; Zhang Dejiu

    2013-01-01

    With the development of low-noise aircraft engine,airframe noise now represents a major noise source during the commercial aircraft's approach to landing phase.Noise control efforts have therefore been extensively focused on the airframe noise problems in order to further reduce aircraft overall noise.In this review,various control methods explored in the last decades for noise reduction on airframe components including high-lift devices and landing gears are summarized.We introduce recent major achievements in airframe noise reduction with passive control methods such as fairings,deceleration plates,splitter plates,acoustic liners,slat cove cover and side-edge replacements,and then discuss the potential and control mechanism of some promising active flow control strategies for airframe noise reduction,such as plasma technique and air blowing/suction devices.Based on the knowledge gained throughout the extensively noise control testing,a few design concepts on the landing gear,high-lift devices and whole aircraft are provided for advanced aircraft low-noise design.Finally,discussions and suggestions are given for future research on airframe noise reduction.

  19. Improved Droop Control Strategy for Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Abusara, Mohammad; Sharkh, Suleiman; Guerrero, Josep M.

    2015-01-01

    An improved control strategy for grid-connected inverters within microgrids is presented in this paper. The strategy is based on the classical P-ω and Q-V droop method. The improvement in the proposed control strategy is twofold: Firstly, the transient response of the droop controller is improved...... are presented to validate the model and demonstrate the controller capabilities....

  20. Regenerative Braking Control Strategy of Electric-Hydraulic Hybrid (EHH Vehicle

    Directory of Open Access Journals (Sweden)

    Yang Yang

    2017-07-01

    Full Text Available A novel electric-hydraulic hybrid drivetrain incorporating a set of hydraulic systems is proposed for application in a pure electric vehicle. Models of the electric and hydraulic components are constructed. Two control strategies, which are based on two separate rules, are developed; the maximum energy recovery rate strategy adheres to the rule of the maximization of the braking energy recovery rate, while the minimum current impact strategy adheres to the rule of the minimization of the charge current to the battery. The simulation models were established to verify the effects of these two control strategies. An ABS (Anti-lock Braking System fuzzy control strategy is also developed and simulated. The simulation results demonstrate that the developed control strategy can effectively absorb the braking energy, suppress the current impact, and assure braking safety.

  1. Genetic control of mosquitoes: population suppression strategies.

    Science.gov (United States)

    Wilke, André Barretto Bruno; Marrelli, Mauro Toledo

    2012-01-01

    Over the last two decades, morbidity and mortality from malaria and dengue fever among other pathogens are an increasing Public Health problem. The increase in the geographic distribution of vectors is accompanied by the emergence of viruses and diseases in new areas. There are insufficient specific therapeutic drugs available and there are no reliable vaccines for malaria or dengue, although some progress has been achieved, there is still a long way between its development and actual field use. Most mosquito control measures have failed to achieve their goals, mostly because of the mosquito's great reproductive capacity and genomic flexibility. Chemical control is increasingly restricted due to potential human toxicity, mortality in no target organisms, insecticide resistance, and other environmental impacts. Other strategies for mosquito control are desperately needed. The Sterile Insect Technique (SIT) is a species-specific and environmentally benign method for insect population suppression, it is based on mass rearing, radiation mediated sterilization, and release of a large number of male insects. Releasing of Insects carrying a dominant lethal gene (RIDL) offers a solution to many of the drawbacks of traditional SIT that have limited its application in mosquitoes while maintaining its environmentally friendly and species-specific utility. The self-limiting nature of sterile mosquitoes tends to make the issues related to field use of these somewhat less challenging than for self-spreading systems characteristic of population replacement strategies. They also are closer to field use, so might be appropriate to consider first. The prospect of genetic control methods against mosquito vectored human diseases is rapidly becoming a reality, many decisions will need to be made on a national, regional and international level regarding the biosafety, social, cultural and ethical aspects of the use and deployment of these vector control methods.

  2. Genetic Control of Mosquitoes: population suppression strategies

    Directory of Open Access Journals (Sweden)

    André Barretto Bruno Wilke

    2012-10-01

    Full Text Available Over the last two decades, morbidity and mortality from malaria and dengue fever among other pathogens are an increasing Public Health problem. The increase in the geographic distribution of vectors is accompanied by the emergence of viruses and diseases in new areas. There are insufficient specific therapeutic drugs available and there are no reliable vaccines for malaria or dengue, although some progress has been achieved, there is still a long way between its development and actual field use. Most mosquito control measures have failed to achieve their goals, mostly because of the mosquito's great reproductive capacity and genomic flexibility. Chemical control is increasingly restricted due to potential human toxicity, mortality in no target organisms, insecticide resistance, and other environmental impacts. Other strategies for mosquito control are desperately needed. The Sterile Insect Technique (SIT is a species-specific and environmentally benign method for insect population suppression, it is based on mass rearing, radiation mediated sterilization, and release of a large number of male insects. Releasing of Insects carrying a dominant lethal gene (RIDL offers a solution to many of the drawbacks of traditional SIT that have limited its application in mosquitoes while maintaining its environmentally friendly and species-specific utility. The self-limiting nature of sterile mosquitoes tends to make the issues related to field use of these somewhat less challenging than for self-spreading systems characteristic of population replacement strategies. They also are closer to field use, so might be appropriate to consider first. The prospect of genetic control methods against mosquito vectored human diseases is rapidly becoming a reality, many decisions will need to be made on a national, regional and international level regarding the biosafety, social, cultural and ethical aspects of the use and deployment of these vector control methods.

  3. Controlling local currents in molecular junctions

    CERN Document Server

    Yadalam, Hari Kumar

    2016-01-01

    The effect of non-equilibrium constraints and dephasing on the circulating currents in molecular junctions are analyzed. Circulating currents are manifestations of quantum effects and can be induced either by externally applied bias or an external magnetic field through the molecular system. In symmetric Aharonov-Bohm ring, bond currents have two contributions, bias driven and magnetic field driven. We analyze the competition between these two contributions and show that, as a consequence, current through one of the branches can be completely suppressed. We then study the effect of asymmetry (as a result of chemical substitution) on the current pathways inside the molecule and study asymmetry induced circulating currents (without magnetic field) by tuning the coupling strength of the substituent (at finite bias).

  4. Evaluating paratransgenesis as a potential control strategy for African trypanosomiasis.

    Science.gov (United States)

    Medlock, Jan; Atkins, Katherine E; Thomas, David N; Aksoy, Serap; Galvani, Alison P

    2013-01-01

    Genetic-modification strategies are currently being developed to reduce the transmission of vector-borne diseases, including African trypanosomiasis. For tsetse, the vector of African trypanosomiasis, a paratransgenic strategy is being considered: this approach involves modification of the commensal symbiotic bacteria Sodalis to express trypanosome-resistance-conferring products. Modified Sodalis can then be driven into the tsetse population by cytoplasmic incompatibility (CI) from Wolbachia bacteria. To evaluate the effectiveness of this paratransgenic strategy in controlling African trypanosomiasis, we developed a three-species mathematical model of trypanosomiasis transmission among tsetse, humans, and animal reservoir hosts. Using empirical estimates of CI parameters, we found that paratransgenic tsetse have the potential to eliminate trypanosomiasis, provided that any extra mortality caused by Wolbachia colonization is low, that the paratransgene is effective at protecting against trypanosome transmission, and that the target tsetse species comprises a large majority of the tsetse population in the release location.

  5. Current and emerging treatment strategies for Duchenne muscular dystrophy

    Directory of Open Access Journals (Sweden)

    Mah JK

    2016-07-01

    Full Text Available Jean K Mah Department of Pediatrics and Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada Abstract: Duchenne muscular dystrophy (DMD is the most common form of muscular dystrophy in childhood. It is caused by mutations of the DMD gene, leading to progressive muscle weakness, loss of independent ambulation by early teens, and premature death due to cardiorespiratory complications. The diagnosis can usually be made after careful review of the history and examination of affected boys presenting with developmental delay, proximal weakness, and elevated serum creatine kinase, plus confirmation by muscle biopsy or genetic testing. Precise characterization of the DMD mutation is important for genetic counseling and individualized treatment. Current standard of care includes the use of corticosteroids to prolong ambulation and to delay the onset of secondary complications. Early use of cardioprotective agents, noninvasive positive pressure ventilation, and other supportive strategies has improved the life expectancy and health-related quality of life for many young adults with DMD. New emerging treatment includes viral-mediated microdystrophin gene replacement, exon skipping to restore the reading frame, and nonsense suppression therapy to allow translation and production of a modified dystrophin protein. Other potential therapeutic targets involve upregulation of compensatory proteins, reduction of the inflammatory cascade, and enhancement of muscle regeneration. So far, data from DMD clinical trials have shown limited success in delaying disease progression; unforeseen obstacles included immune response against the generated mini-dystrophin, inconsistent evidence of dystrophin production in muscle biopsies, and failure to demonstrate a significant improvement in the primary outcome measure, as defined by the 6-minute walk test in some studies. The long-term safety and efficacy of emerging treatments

  6. Bariatric emergencies: current evidence and strategies of management

    Science.gov (United States)

    2013-01-01

    Background The demand for bariatric surgery is increasing and the postoperative complications are seen more frequently. The aim of this paper is to review the current outcomes of bariatric surgery emergencies and to formulate a pathway of safe management. Methods The PubMed and Google search for English literatures relevant to emergencies of bariatric surgery was made, 6358 articles were found and 90 papers were selected based on relevance, power of the study, recent papers and laparoscopic workload. The pooled data was collected from these articles that were addressing the complications and emergency treatment of bariatric patients. 830,998 patients were included in this review. Results Bariatric emergencies were increasingly seen in the Accident and Emergency departments, the serious outcomes were reported following complex operations like gastric bypass but also after gastric band and the causes were technical errors, suboptimal evaluation, failure of effective communication with bariatric teams who performed the initial operation, patients factors, and delay in the presentation. The mortality ranged from 0.14%-2.2% and increased for revisional surgery to 6.5% (p = 0.002). Inspite of this, mortality following bariatric surgery is still less than that of control group of obese patients (p = value 0.01). Conclusions Most mortality and catastrophic outcomes following bariatric surgery are preventable. The awareness of bariatric emergencies and its effective management are the gold standards for best outcomes. An algorithm is suggested and needs further evaluation. PMID:24373182

  7. Neural PID Control Strategy for Networked Process Control

    Directory of Open Access Journals (Sweden)

    Jianhua Zhang

    2013-01-01

    Full Text Available A new method with a two-layer hierarchy is presented based on a neural proportional-integral-derivative (PID iterative learning method over the communication network for the closed-loop automatic tuning of a PID controller. It can enhance the performance of the well-known simple PID feedback control loop in the local field when real networked process control applied to systems with uncertain factors, such as external disturbance or randomly delayed measurements. The proposed PID iterative learning method is implemented by backpropagation neural networks whose weights are updated via minimizing tracking error entropy of closed-loop systems. The convergence in the mean square sense is analysed for closed-loop networked control systems. To demonstrate the potential applications of the proposed strategies, a pressure-tank experiment is provided to show the usefulness and effectiveness of the proposed design method in network process control systems.

  8. Novel strategies for control of fermentation processes

    DEFF Research Database (Denmark)

    Mears, Lisa

    to highly optimised industrial host strains. The focus of this project is instead on en-gineering of the process. The question to be answered in this thesis is, given a highly optimised industrial host strain, how can we operate the fermentation process in order to maximise the productivity of the system...... (2012). This model describes the fungal processes operated in the fermentation pilot plant at Novozymes A/S. This model is investigated using uncertainty analysis methods in order to as-sess the applicability to control applications. A mechanistic model approach is desirable, as it is a predictive....... This provides a prediction of the future trajectory of the process, so that it is possible to guide the system to the desired target mass. The control strategy is applied on-line at 550L scale in the Novozymes A/S fermentation pilot plant, and the method is challenged with four different sets of process...

  9. Nonlinear Control Strategies for Bioprocesses: Sliding Mode Control versus Vibrational Control

    OpenAIRE

    Selisteanu, Dan; Petre, Emil; Popescu, Dorin; Bobasu, Eugen

    2008-01-01

    In this work, two nonlinear high-frequency control strategies for bioprocesses are proposed: a feedback sliding mode control law and a vibrational control strategy. In order to implement these strategies, a prototype bioprocess that is carried out in a Continuous Stirred Tank Bioreactor was considered. First, a discontinuous feedback law was designed using the exact linearization and by imposing a SMC that stabilizes the output of the bioprocess. When some state variables used in the control ...

  10. Strategies For Malaria Control In Mangalore City

    Directory of Open Access Journals (Sweden)

    Kiran Udaya .N

    1999-01-01

    Full Text Available Research questions: What different strategies should be used to effectively control problem of malaria? Objectives: 1 To study the problem of malaria. 2 To study different strategies for effective control of malaria. Study design: Observational and record based. The problem of malaria was studied for three years from 1996-1998 Participants: Individuals having fever. Setting: Community based in Mangalore City. Study variables: Fever cases, blood slides prepared, slides found positive, agency-wise, species-wise and year-wise positivity. Statistical methods: Simple proportions. Results: The yield of cases has been shown to highest in passive surveillance, as reflected in high slide positivity rates. A total of 95,898 slides were prepared, out of which 19,169 were positive for malaria parasite. Thus, the overall side positivity was 20%. The SPR in passive surveillance was 34.5%. Month-wise distribution of positive cases showed high SPR and low Pv/Pf ratios during non-malaria seasons. It is suggested to improve passive surveillance to achieve high SPR thereby leading to substantial saving on slides, laboratory services and transport expenditure.

  11. Improved Control Strategy for Active Bouncers used in Klystron Modulators

    CERN Document Server

    Aguglia, D; Benedetti, M; Garcia Retegui, R; Maestri, S; Nisbet, D

    2012-01-01

    This paper introduces a closed-loop control system for klystron modulators. The system is based on the discharge of a capacitor into a step-up voltage transformer and an active bouncer implemented with a multiphase buck converter. In order to obtain a constant Klystron voltage at the at-top, the active bouncer must compensate both the capacitor discharge and the pulse transformer characteristic. The proposed control includes an inner voltage regulation loop that controls the active bouncer output voltage and an outer one that controls the klystron voltage. The primary side current and main capacitor voltage are included in the regulation loops to simplify the controllers. Simulations demonstrate that the strategy adopted allows to obtain a precision better than 0:1% on a 110 kV klystron. Experimental tests have shown that the multiphase converter is able to track a high dynamics reference even under variable output voltage conditions.

  12. Economic Effects of Introducing Alternative Salmonella Control Strategies in Sweden

    Science.gov (United States)

    Sundström, Kristian; Wahlström, Helene; Ivarsson, Sofie; Sternberg Lewerin, Susanna

    2014-01-01

    The objective of the study was to analyse the economic effects of introducing alternative Salmonella control strategies in Sweden. Current control strategies in Denmark and the Netherlands were used as benchmarks. The true number of human Salmonella cases was estimated by reconstructing the reporting pyramids for the various scenarios. Costs were calculated for expected changes in human morbidity (Salmonella and two of its sequelae), for differences in the control programmes and for changes in cattle morbidity. The net effects (benefits minus costs) were negative in all scenarios (€ −5 to −105 million), implying that it would not be cost-effective to introduce alternative control strategies in Sweden. This result was mainly due to an expected increase in the incidence of Salmonella in humans (6035–57108 reported and unreported new cases/year), with expected additional costs of € 5–55 million. Other increased costs were due to expected higher incidences of sequelae (€ 3–49 million) and a higher cattle morbidity (€ 4–8 million). Benefits in terms of lower control costs amounted to € 4–7 million. PMID:24831797

  13. Hysteresis Current Control technique based on Space Vector Modulation for Active Power Filter

    Directory of Open Access Journals (Sweden)

    Wang Yun-liang

    2011-09-01

    Full Text Available In this paper, the hysteresis current control (HCC technique based on space vector modulation (SVM for shunt active power filter (APF is proposed. The switching control algorithms of the HCC based SVM manage to generate compensated current according to the reference current. Harmonics extraction is based on the instantaneous active and reactive power theorem in time domain by calculating the power compensation. A closed loop control system is carried out and the error current is the difference between the reference current which is obtained from the power compensation and the actual current needs to be injected back into the power grid. By implementing this control strategy, the APF manages to generate better compensated harmonics currents to the power grid. Keywords: active power filter, hysteresis current control, space vector modulation ,matlab/simulink

  14. Nosocomial infections and their control strategies

    Directory of Open Access Journals (Sweden)

    Hassan Ahmed Khan

    2015-07-01

    Full Text Available Nosocomial infections are also known as hospital-acquired/associated infections. National Healthcare Safety Network along with Centers for Disease Control for surveillance has classified nosocomial infection sites into 13 types with 50 infection sites, which are specific on the basis of biological and clinical criteria. The agents that are usually involved in hospital-acquired infections include Streptococcus spp., Acinetobacter spp., enterococci, Pseudomonas aeruginosa, coagulase-negative staphylococci, Staphylococcus aureus, Bacillus cereus, Legionella and Enterobacteriaceae family members, namely, Proteus mirablis, Klebsiella pneumonia, Escherichia coli, Serratia marcescens. Nosocomial pathogens can be transmitted through person to person, environment or contaminated water and food, infected individuals, contaminated healthcare personnel's skin or contact via shared items and surfaces. Mainly, multi-drug-resistant nosocomial organisms include methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, Pseudomonas aeruginosa and Klebsiella pneumonia, whereas Clostridium difficile shows natural resistance. Excessive and improper use of broad-spectrum antibiotics, especially in healthcare settings, is elevating nosocomial infections, which not only becomes a big health care problem but also causes great economic and production loss in the community. Nosocomial infections can be controlled by measuring and comparing the infection rates within healthcare settings and sticking to the best healthcare practices. Centers for Disease Control and Prevention provides the methodology for surveillance of nosocomial infections along with investigation of major outbreaks. By means of this surveillance, hospitals can devise a strategy comprising of infection control practices.

  15. Nosocomial infections and their control strategies

    Institute of Scientific and Technical Information of China (English)

    Hassan Ahmed Khan; Aftab Ahmad; Riffat Mehboob

    2015-01-01

    Nosocomial infections are also known as hospital-acquired/associated infections. National Healthcare Safety Network along with Centers for Disease Control for surveillance has classified nosocomial infection sites into 13 types with 50 infection sites, which are specific on the basis of biological and clinical criteria. The agents that are usually involved in hospital-acquired infections include Streptococcus spp., Acinetobacter spp., enterococci, Pseudomonas aeruginosa, coagulase-negative staphylococci, Staphylococcus aureus, Bacillus cereus, Legionella and Enterobacteriaceae family members, namely, Proteus mirablis, Klebsiella pneumonia, Escherichia coli, Serratia marcescens. Nosocomial pathogens can be transmitted through person to person, environment or contaminated water and food, infected individuals, contaminated healthcare personnel’s skin or contact via shared items and surfaces. Mainly, multi-drug-resistant nosocomial organisms include methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, Pseudomonas aeruginosa and Klebsiella pneumonia, whereas Clostridium dififcile shows natural resistance. Excessive and improper use of broad-spectrum antibiotics, especially in healthcare settings, is elevating nosocomial infections, which not only becomes a big health care problem but also causes great economic and production loss in the community. Nosocomial infections can be controlled by measuring and comparing the infection rates within healthcare settings and sticking to the best healthcare practices. Centers for Disease Control and Prevention provides the methodology for surveillance of nosocomial infections along with investigation of major outbreaks. By means of this surveillance, hospitals can devise a strategy comprising of infection control practices.

  16. Nosocomial infections and their control strategies

    Institute of Scientific and Technical Information of China (English)

    Hassan; Ahmed; Khan; Aftab; Ahmad; Riffat; Mehboob

    2015-01-01

    Nosocomial infections are also known as hospital-acquired/associated infections. National Healthcare Safety Network along with Centers for Disease Control for surveillance has classified nosocomial infection sites into 13 types with 50 infection sites, which are specific on the basis of biological and clinical criteria. The agents that are usually involved in hospitalacquired infections include Streptococcus spp., Acinetobacter spp., enterococci, Pseudomonas aeruginosa, coagulase-negative staphylococci, Staphylococcus aureus, Bacillus cereus, Legionella and Enterobacteriaceae family members, namely, Proteus mirablis, Klebsiella pneumonia, Escherichia coli, Serratia marcescens. Nosocomial pathogens can be transmitted through person to person, environment or contaminated water and food, infected individuals, contaminated healthcare personnel’s skin or contact via shared items and surfaces. Mainly, multi-drug-resistant nosocomial organisms include methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, Pseudomonas aeruginosa and Klebsiella pneumonia, whereas Clostridium difficile shows natural resistance. Excessive and improper use of broadspectrum antibiotics, especially in healthcare settings, is elevating nosocomial infections, which not only becomes a big health care problem but also causes great economic and production loss in the community. Nosocomial infections can be controlled by measuring and comparing the infection rates within healthcare settings and sticking to the best healthcare practices. Centers for Disease Control and Prevention provides the methodology for surveillance of nosocomial infections along with investigation of major outbreaks. By means of this surveillance, hospitals can devise a strategy comprising of infection control practices.

  17. Companies on Facebook and Twitter. Current situation and communication strategies

    Directory of Open Access Journals (Sweden)

    JÁ Pérez Dasilva

    2013-10-01

    Full Text Available Introduction. Given their influence, companies are being forced to integrate social networks in their communication strategies. Objectives. This article aims to provide an overview of the use of Facebook and Twitter by the main commercial brands in Spain and to analyse the communication strategies of the companies that tend to receive more complaints from the public. Method. The study is based on the examination of the social network accounts of the three brands with the highest advertising investment in each of the 15 industry sectors. A total of 5,433 tweets and 3,000 posts were analysed. Conclusions. The study confirmed the massive presence of these companies is the social networks and demonstrated the extreme variability of the number of followers, the traffic and the nature of the information published. However, it was also demonstrated that the use made of the different social networks and the communication strategies required by the different companies are distinguishable and identifiable.

  18. Current Management Strategy for Active Surveillance in Prostate Cancer.

    Science.gov (United States)

    Syed, Jamil S; Javier-Desloges, Juan; Tatzel, Stephanie; Bhagat, Ansh; Nguyen, Kevin A; Hwang, Kevin; Kim, Sarah; Sprenkle, Preston C

    2017-02-01

    Active surveillance has been increasingly utilized as a strategy for the management of favorable-risk, localized prostate cancer. In this review, we describe contemporary management strategies of active surveillance, with a focus on traditional stratification schemes, new prognostic tools, and patient outcomes. Patient selection, follow-up strategy, and indication for delayed intervention for active surveillance remain centered around PSA, digital rectal exam, and biopsy findings. Novel tools which include imaging, biomarkers, and genetic assays have been investigated as potential prognostic adjuncts; however, their role in active surveillance remains institutionally dependent. Although 30-50% of patients on active surveillance ultimately undergo delayed treatment, the vast majority will remain free of metastasis with a low risk of dying from prostate cancer. The optimal method for patient selection into active surveillance is unknown; however, cancer-specific mortality rates remain excellent. New prognostication tools are promising, and long-term prospective, randomized data regarding their use in active surveillance will be beneficial.

  19. Intelligent Control Strategy for Dynamic Zero-Energy-Facades

    DEFF Research Database (Denmark)

    Winther, Frederik Vildbrad; Heiselberg, Per; Jensen, Rasmus Lund

    2016-01-01

    control strategies and their potential when applied in different climatic locations. The control strategies are furthermore tested in full scale at a test facility at Aalborg University in order to test the performance of the control strategies in relation to the thermal indoor climate through use...

  20. 40 CFR 123.46 - Individual control strategies.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 21 2010-07-01 2010-07-01 false Individual control strategies. 123.46... PROGRAM REQUIREMENTS Transfer of Information and Permit Review § 123.46 Individual control strategies. (a..., approval, and implementation an individual control strategy for each point source identified by the...

  1. Cost Effectiveness Analysis of Optimal Malaria Control Strategies in Kenya

    Directory of Open Access Journals (Sweden)

    Gabriel Otieno

    2016-03-01

    Full Text Available Malaria remains a leading cause of mortality and morbidity among the children under five and pregnant women in sub-Saharan Africa, but it is preventable and controllable provided current recommended interventions are properly implemented. Better utilization of malaria intervention strategies will ensure the gain for the value for money and producing health improvements in the most cost effective way. The purpose of the value for money drive is to develop a better understanding (and better articulation of costs and results so that more informed, evidence-based choices could be made. Cost effectiveness analysis is carried out to inform decision makers on how to determine where to allocate resources for malaria interventions. This study carries out cost effective analysis of one or all possible combinations of the optimal malaria control strategies (Insecticide Treated Bednets—ITNs, Treatment, Indoor Residual Spray—IRS and Intermittent Preventive Treatment for Pregnant Women—IPTp for the four different transmission settings in order to assess the extent to which the intervention strategies are beneficial and cost effective. For the four different transmission settings in Kenya the optimal solution for the 15 strategies and their associated effectiveness are computed. Cost-effective analysis using Incremental Cost Effectiveness Ratio (ICER was done after ranking the strategies in order of the increasing effectiveness (total infections averted. The findings shows that for the endemic regions the combination of ITNs, IRS, and IPTp was the most cost-effective of all the combined strategies developed in this study for malaria disease control and prevention; for the epidemic prone areas is the combination of the treatment and IRS; for seasonal areas is the use of ITNs plus treatment; and for the low risk areas is the use of treatment only. Malaria transmission in Kenya can be minimized through tailor-made intervention strategies for malaria control

  2. Modeling Responses of Leafy Spurge Dispersal to Control Strategies

    Institute of Scientific and Technical Information of China (English)

    Zewei Miao

    2007-01-01

    Leafy spurge (Euphorbia esula L.) has substantial negative effects on grassland biodiversity, productivity, and economic benefit in North America.To predict these negative impacts, we need an appropriate plant-spread model which can simulate the response of an invading population to different control strategies.In this study, using a stochastic map lattice approach we generated a spatially explicitly stochastic process-based model to simulate dispersal trajectories of leafy spurge under various control scenarios.The model integrated dispersal curve, propagule pressure, and population growth of leafy spurge at local and short-temporal scales to capture spread features of leafy spurge at large spatial and long-temporal scales.Our results suggested that narrow-, medium-, and fat-tailed kernels did not differ In their ability to predict spread, in contrast to previous works.For all kernels, Allee effects were significantly present and could explain the lag phase (three decades)before leafy spurge spread accelerated.When simulating from the initial stage of introduction, Allee effects were critical in predicting spread rate of leafy spurge, because the prediction could be seriously affected by the low density period of leafy spurge community.No Allee effects models were not able to simulate spread rate well in this circumstance.When applying control strategies to the current diatribution, Allee effects could stop the spread of leafy spurge; no Allee effects models, however, were able to slow but not stop the spread.The presence of Allee effects had significant ramifications on the efficiencies of control strategies.For both Allee and no Allee effects models, the later that control strategies were implemented, the more effort had to be input to achieve similar control results.

  3. Multi-frequency proportional-resonant (MFPR) current controller for PWM VSC under unbalanced supply conditions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This letter presents a multi-frequency proportional-resonant (MFPR) current controller developed for PWM voltage source converter (VSC) under the unbalanced supply voltage conditions. The delta operator is used in place of the shift operator for the implementation of MFPR by using a low-cost fixed-point DSP. The experimental results with an alternative control strategy validated the feasibility of the proposed MFPR current controller for the PWM VSC during voltage unbalance.

  4. Improved control strategy for the three-phase grid-connected inverter

    DEFF Research Database (Denmark)

    Yao, Zhilei; Xiao, Lan; Guerrero, Josep M.

    2015-01-01

    An improved control strategy for the three-phase grid-connected inverter with space vector pulse width modulation (SVPWM) is proposed. When the grid current contains harmonics, the d- and q-axis grid currents will be interacted, and then the waveform quality of the grid current will be poorer...... strategy, the grid-connected inverter with the improved control strategy has high waveform quality of the grid current, small ripple power, and fast dynamic response........ As the reference output voltage cannot directly reflect the change of the reference grid current, the dynamic response of the grid-connected inverter is slow. In order to solve the aforementioned problems, the d- and q-axis grid currents in the decoupled components of the grid current controller can be substituted...

  5. [Harm reduction strategy in tobacco control].

    Science.gov (United States)

    Gorini, Giuseppe

    2011-01-01

    .Thus, California Department of Health Services prohibits promotion of snus and medicinal nicotine as a harm reduction strategy. However, the US Federal Family Smoking Prevention and Tobacco Control Act, signed by President Obama in 2009, places tobacco products under FDA jurisdiction: FDA must define criteria for lowering carcinogens and toxicants in tobacco products, making more available medicinal nicotine, evaluating PREPs, creating a federal Tobacco Control Agency.Which approaches is Italy going to follow?

  6. Current strategies for drug delivery to the inner ear

    Directory of Open Access Journals (Sweden)

    Hongzhuo Liu

    2013-04-01

    Full Text Available For many years, drug delivery to the inner ear has been a challenge to physicians in the treatment of inner ear disorders. In the past decade, the field of inner ear drug delivery has emerged with the development of new biomaterials and drug delivery technologies to improve the effectiveness of inner ear drug therapy. This paper reviews a number of inner ear drug delivery strategies including systemic, intratympanic, and intracochlear delivery. A focus of this review is the recent advances in intratympanic delivery of medications; approaches utilizing novel biomaterials as well as other recent developments are also discussed. Biotechnology-based approaches, such as gene and stem cell therapy methods are also reviewed. Among the various strategies, local drug delivery approaches including intratympanic and intracochlear drug delivery methods that limit systemic exposure are particularly promising. These inner ear drug delivery systems provide a new opportunity to improve the treatment of inner ear disorders.

  7. Current Strategies to Improve the Bioactivity of PEEK

    Directory of Open Access Journals (Sweden)

    Rui Ma

    2014-03-01

    Full Text Available The synthetic thermoplastic polymer polyetheretherketone (PEEK is becoming a popular component of clinical orthopedic and spinal applications, but its practical use suffers from several limitations. Although PEEK is biocompatible, chemically stable, radiolucent and has an elastic modulus similar to that of normal human bone, it is biologically inert, preventing good integration with adjacent bone tissues upon implantation. Recent efforts have focused on increasing the bioactivity of PEEK to improve the bone-implant interface. Two main strategies have been used to overcome the inert character of PEEK. One approach is surface modification to activate PEEK through surface treatment alone or in combination with a surface coating. Another strategy is to prepare bioactive PEEK composites by impregnating bioactive materials into PEEK substrate. Researchers believe that modified bioactive PEEK will have a wide range of orthopedic applications.

  8. Prevention of OHSS: Current strategies and new insights

    Directory of Open Access Journals (Sweden)

    Cristiano E. Busso

    2010-10-01

    Full Text Available Ovarian hyperstimulation syndrome (OHSS is an iatrogenic and potentially life threatening condition that affects young healthy patients. Many strategies have been proposed to prevent this syndrome. However, to avoid OHSS without compromising on IVF outcome is still a challenge. The most important action is to identify patients at risk even before ovarian stimulation is initiated and to give them special attention. Coasting is the most popular method to avoid/minimize OHSS. Cycle cancellation, cryopreservation, GnRH antagonists, GnRH agonists, i.v. albumin are other strategies that can provide some kind of benefit but do not completely avoid both early and late forms of OHSS and/or cannot be applied to every patient. Recent studies demonstrate that dopamine agonists can prevent or minimize OHSS without affecting IVF outcome but clinical protocols are not well established yet.

  9. MicroRNA Detection: Current Technology and Research Strategies

    Science.gov (United States)

    Hunt, Eric A.; Broyles, David; Head, Trajen; Deo, Sapna K.

    2015-07-01

    The relatively new field of microRNA (miR) has experienced rapid growth in methodology associated with its detection and bioanalysis as well as with its role in -omics research, clinical diagnostics, and new therapeutic strategies. The breadth of this area of research and the seemingly exponential increase in number of publications on the subject can present scientists new to the field with a daunting amount of information to evaluate. This review aims to provide a collective overview of miR detection methods by relating conventional, established techniques [such as quantitative reverse transcription polymerase chain reaction (RT-qPCR), microarray, and Northern blotting (NB)] and relatively recent advancements [such as next-generation sequencing (NGS), highly sensitive biosensors, and computational prediction of microRNA/targets] to common miR research strategies. This should guide interested readers toward a more focused study of miR research and the surrounding technology.

  10. 我国海产品中副溶血性弧菌的污染现状与控制策略分析%Analysis on current pollution of Vibrio parahemolyticus in seafood in China and its controlling strategy

    Institute of Scientific and Technical Information of China (English)

    韩小龙; 张海燕; 曹明秀; 沈晓盛

    2015-01-01

    副溶血性弧菌是一种典型的海洋性食源性致病菌,是近年来我国特别是沿海地区引起细菌性食物中毒的首要致病菌.据估计,我国每年因副溶血性弧菌感染而导致的食源性疾病发病高达495.1万人次.为了进一步掌握副溶血性弧菌在我国的污染现状和发展趋势,文中分析了副溶血性弧菌近十年的流行病学概况,同时选取了我国24个大中型海产品主要消费城市作为分析对象,分别从副溶血性弧菌的整体检出率、时空变化以及品种间差异3个方面逐一分析了2006年~2013年期间各城市的污染调查数据.并对该菌在污染源头、流通、销售和消费过程中的现有控制措施进行了比较和分析.以期为更好地控制副溶血性弧菌引发食源性疾病的发生提供参考依据,从而进一步降低我国因食用海产品而导致食源性疾病发生的风险.%Vibrio parahemolyticus is a kind of typical oceanic foodborne pathogenic bacteria,which is also a primary food poisoning pathogen in China in recent years,especially in coastal areas.It is considered that the number of foodborne disease caused by Vibrio parahemolyticus is as high as 4.951 million in China each year.In order to investigate the pollution situation of Vibrio parahemolyticus and its development tendency in China,the epidemiological survey of Vibrio parahemolyticus for the last decade was analyzed in this paper.24 cities with large seafood consumption in China were chosen as the analysis object.The pollution data of each city during 2006-2013 were analyzed from 3 aspects including overall detection rate,time and space change,and difference between varieties.The existing strategy to control Vibrio parahemolyticus were respectively compared and analyzed from 4 aspects including pollution source,transportation,sales and consumption,so as to provide a reference to control foodborne diseases caused by Vibrio parahemolyticus and reduce the risk of

  11. Current strategies for the prevention of breast cancer

    OpenAIRE

    Advani P; Moreno-Aspitia A

    2014-01-01

    Pooja Advani, Alvaro Moreno-AspitiaDepartment of Hematology and Oncology, Mayo Clinic, Jacksonville, FL, USAAbstract: Due to the high incidence of breast cancer in the United States, optimal strategies for its prevention are imperative. This entails identification of women who are at an increased risk for breast cancer and an integrative approach that includes effective screening methods as well as nutritional, pharmacologic, and surgical management. Several breast cancer risk-assessment tool...

  12. Modelling strategies for controlling SARS outbreaks.

    Science.gov (United States)

    Gumel, Abba B.; Ruan, Shigui; Day, Troy; Watmough, James; Brauer, Fred; van den Driessche, P.; Gabrielson, Dave; Bowman, Chris; Alexander, Murray E.; Ardal, Sten; Wu, Jianhong; Sahai, Beni M.

    2004-01-01

    Severe acute respiratory syndrome (SARS), a new, highly contagious, viral disease, emerged in China late in 2002 and quickly spread to 32 countries and regions causing in excess of 774 deaths and 8098 infections worldwide. In the absence of a rapid diagnostic test, therapy or vaccine, isolation of individuals diagnosed with SARS and quarantine of individuals feared exposed to SARS virus were used to control the spread of infection. We examine mathematically the impact of isolation and quarantine on the control of SARS during the outbreaks in Toronto, Hong Kong, Singapore and Beijing using a deterministic model that closely mimics the data for cumulative infected cases and SARS-related deaths in the first three regions but not in Beijing until mid-April, when China started to report data more accurately. The results reveal that achieving a reduction in the contact rate between susceptible and diseased individuals by isolating the latter is a critically important strategy that can control SARS outbreaks with or without quarantine. An optimal isolation programme entails timely implementation under stringent hygienic precautions defined by a critical threshold value. Values below this threshold lead to control, but those above are associated with the incidence of new community outbreaks or nosocomial infections, a known cause for the spread of SARS in each region. Allocation of resources to implement optimal isolation is more effective than to implement sub-optimal isolation and quarantine together. A community-wide eradication of SARS is feasible if optimal isolation is combined with a highly effective screening programme at the points of entry. PMID:15539347

  13. Global elimination of mother-to-child transmission of hepatitis B: revisiting the current strategy.

    Science.gov (United States)

    Thio, Chloe L; Guo, Nan; Xie, Chan; Nelson, Kenrad E; Ehrhardt, Stephan

    2015-08-01

    Mother-to-child transmission (MTCT) of hepatitis B virus (HBV) is a major route of HBV transmission worldwide despite an existing immunoprophylaxis regimen. The implementation of immunoprophylaxis has been challenging, especially in low-income and middle-income countries, where MTCT is common, because of difficulty obtaining and delivering the monovalent HBV vaccine and the HBV immunoglobulin. Global control of the HBV epidemic will need improved prevention of MTCT. We discuss research gaps that hinder development of new options for the elimination of MTCT as well as policy changes that may help the current vaccine-based strategy to live up to its full potential. We propose that decreasing hepatitis B viral concentrations before delivery, along with HBV vaccine use, could provide an alternative strategy that would decrease MTCT of HBV.

  14. Coordination Control Strategy for Compound Fault of MMC-HVDC

    Directory of Open Access Journals (Sweden)

    Zhang Ming Guang

    2016-01-01

    Full Text Available Single-line to ground fault of DC side and sub-module fault are typical faults of MMC-HVDC. When each of the above faults occurs, the system will give a signal for circuit-breaker releasing, this will result in interruption of power delivery, the stability of the system is greatly reduced. When these two faults occur simultaneously, research on control strategy for compound fault will help to improve the reliability of the system. While single-line to ground fault of DC side happens, only the electric potential auxiliary point of DC side is changed, system’s power transport normally. When sub-module is fault, redundancy fault-tolerated control strategy is presented, which replace the failed sub-modules with equal number of redundant sub-modules, it can restrain the fluctuation of direct current. A double terminals and 21 voltage-level MMC-HVDC system simulation model is set up in PSCAD/EMTDC. From the computation and simulation results, it is concluded that the proposed control strategy is correct for above compound fault, it can achieve rapid recovery after faults, effectively improve fault tolerance of the system, develop the stability and reliability of the system.

  15. Indoor radon and decay products: Concentrations, causes, and control strategies

    Energy Technology Data Exchange (ETDEWEB)

    Nero, A.V.; Gadgil, A.J.; Nazaroff, W.W.; Revzan, K.L.

    1990-11-01

    This report is another in the on going technical report series that addresses various aspects of the DOE Radon Research Program. It provides an overview of what is known about the behavior of radon and its decay products in the indoor environment and examines the manner in which several important classes of factors -- structural, geological, and meteorological -- affect indoor radon concentrations. Information on US indoor radon concentrations, currently available monitoring methods and novel radon control strategies are also explored. 238 refs., 22 figs., 9 tabs.

  16. Current Therapeutic Strategies and Novel Approaches in Osteosarcoma

    Science.gov (United States)

    Ando, Kosei; Heymann, Marie-Françoise; Stresing, Verena; Mori, Kanji; Rédini, Françoise; Heymann, Dominique

    2013-01-01

    Osteosarcoma is the most frequent malignant primary bone tumor and a main cause of cancer-related death in children and adolescents. Although long-term survival in localized osteosarcoma has improved to about 60% during the 1960s and 1970s, long-term survival in both localized and metastatic osteosarcoma has stagnated in the past several decades. Thus, current conventional therapy consists of multi-agent chemotherapy, surgery and radiation, which is not fully adequate for osteosarcoma treatment. Innovative drugs and approaches are needed to further improve outcome in osteosarcoma patients. This review describes the current management of osteosarcoma as well as potential new therapies. PMID:24216993

  17. Current Therapeutic Strategies and Novel Approaches in Osteosarcoma

    Energy Technology Data Exchange (ETDEWEB)

    Ando, Kosei, E-mail: andokercgv@gmail.com [INSERM, UMR 957, 1 Rue Gaston Veil, 44035 Nantes (France); Physiopathologie de la Résorption Osseuse et Therapie des Tumeurs Osseuses Primitives, Université de Nantes, Nantes Atlantique Universités, 1 Rue Gaston Veil, 44035 Nantes (France); Equipe Labellisee Ligue 2012, Nantes, 44035 (France); Heymann, Marie-Françoise [INSERM, UMR 957, 1 Rue Gaston Veil, 44035 Nantes (France); Physiopathologie de la Résorption Osseuse et Therapie des Tumeurs Osseuses Primitives, Université de Nantes, Nantes Atlantique Universités, 1 Rue Gaston Veil, 44035 Nantes (France); Equipe Labellisee Ligue 2012, Nantes, 44035 (France); Nantes University Hospital, Nantes 44035 (France); Stresing, Verena [INSERM, UMR 957, 1 Rue Gaston Veil, 44035 Nantes (France); Physiopathologie de la Résorption Osseuse et Therapie des Tumeurs Osseuses Primitives, Université de Nantes, Nantes Atlantique Universités, 1 Rue Gaston Veil, 44035 Nantes (France); Nantes University Hospital, Nantes 44035 (France); Mori, Kanji [Department of Orthopaedic Surgery, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga 520-2192 (Japan); Rédini, Françoise; Heymann, Dominique [INSERM, UMR 957, 1 Rue Gaston Veil, 44035 Nantes (France); Physiopathologie de la Résorption Osseuse et Therapie des Tumeurs Osseuses Primitives, Université de Nantes, Nantes Atlantique Universités, 1 Rue Gaston Veil, 44035 Nantes (France); Equipe Labellisee Ligue 2012, Nantes, 44035 (France); Nantes University Hospital, Nantes 44035 (France)

    2013-05-24

    Osteosarcoma is the most frequent malignant primary bone tumor and a main cause of cancer-related death in children and adolescents. Although long-term survival in localized osteosarcoma has improved to about 60% during the 1960s and 1970s, long-term survival in both localized and metastatic osteosarcoma has stagnated in the past several decades. Thus, current conventional therapy consists of multi-agent chemotherapy, surgery and radiation, which is not fully adequate for osteosarcoma treatment. Innovative drugs and approaches are needed to further improve outcome in osteosarcoma patients. This review describes the current management of osteosarcoma as well as potential new therapies.

  18. Optimization of wind farm power production using innovative control strategies

    DEFF Research Database (Denmark)

    Duc, Thomas

    Wind energy has experienced a very significant growth and cost reduction over the past decade, and is now able to compete with conventional power generation sources. New concepts are currently investigated to decrease costs of production of electricity even further. Wind farm coordinated control...... is one of them; it is aimed at increasing the efficiency of a wind farm and decreasing the fatigue loads faced by wind turbines by reducing aerodynamic interactions between them. These objectives are achieved considering two different strategies: curtailing an upwind turbine to reduce the wind speed...... conditions. It is therefore not known to what extent these gains can be reproduced in a real wind farm where wind conditions are very fluctuating. The French national project SMARTEOLE constitutes one of the first attempts of implementing these strategies on a full scale wind farm. A ten month measurement...

  19. Autism Spectrum Disorder: Examining Current Diagnosis Strategies and Assessment Tools

    Science.gov (United States)

    Wormald, Amy Marie

    2011-01-01

    Recent literature notes a significant increase in students being diagnosed with Autism Spectrum Disorder (ASD). Yet, no uniform testing protocol exists. It is vital for students and educators that a unified testing process be created and established. This study investigated which ASD testing instruments were currently used in Southern California…

  20. Book Review: Current Issues in International Human Resource Management and Strategy Research

    DEFF Research Database (Denmark)

    Gretzinger, Susanne

    2009-01-01

    The article reviews the book "Current Issues in International Human Resource Management and Strategy Research," edited by Marion Festing and Susanne Royer.......The article reviews the book "Current Issues in International Human Resource Management and Strategy Research," edited by Marion Festing and Susanne Royer....

  1. Book Review: Current Issues in International Human Resource Management and Strategy Research

    DEFF Research Database (Denmark)

    Gretzinger, Susanne

    2009-01-01

    The article reviews the book "Current Issues in International Human Resource Management and Strategy Research," edited by Marion Festing and Susanne Royer.......The article reviews the book "Current Issues in International Human Resource Management and Strategy Research," edited by Marion Festing and Susanne Royer....

  2. A control strategy for stand-alone wound rotor induction machine

    Energy Technology Data Exchange (ETDEWEB)

    Forchetti, D.G.; Garcia, G.O. [Grupo de Electronica Aplicada (GEA), Universidad Nacional de Rio Cuarto, X5804 BYA Rio Cuarto (Argentina); Solsona, J.A. [Instituto de Investigaciones en Ingenieria Electrica?Alfredo Desages?, Departamento de Ingenieria Electrica y de Computadoras, Universidad Nacional del Sur, Bahia Blanca (Argentina); Valla, M.I. [Laboratorio de Electronica Industrial, Control e Instrumentacion (LEICI), Facultad de Ingenieria, Universidad Nacional de La Plata, 1900 La Plata (Argentina)

    2007-02-15

    A control strategy to regulate the frequency and voltage of a stand-alone wound rotor induction machine is presented. This strategy allows the machine to work as a generator in stand-alone systems (without grid connection) with variable rotor speed. A stator flux-oriented control is proposed using the rotor voltages as actuation variables. Two cascade control loops are used to regulate the stator flux and the rotor currents. A closed loop observer is designed to estimate the machine flux which is necessary to implement these control loops. The proposed control strategy is validated through simulations with satisfactory results. (author)

  3. Advanced Control Strategy of DFIG Wind Turbines for Power System Fault Ride Through

    DEFF Research Database (Denmark)

    Yang, Lihui; Xu, Zhao; Ostergaard, Jacob;

    2012-01-01

    This paper presents an advanced control strategy for the rotor and grid side converters of the doubly fed induction generator (DFIG) based wind turbine (WT) to enhance the low-voltage ride-through (LVRT) capability according to the grid connection requirement. Within the new control strategy...... the oscillations in the stator and rotor currents and the DC bus voltage. The effectiveness of the proposed control strategy has been demonstrated through various simulation cases. Compared with conventional crowbar protection, the proposed control method can not only improve the LVRT capability of the DFIG WT......, but also help maintaining continuous active and reactive power control of the DFIG during the grid faults....

  4. Impedance Based Analysis of DFIG Stator Current Unbalance and Distortion Suppression Strategies

    DEFF Research Database (Denmark)

    Song, Yipeng; Zhou, Dao; Blaabjerg, Frede

    2016-01-01

    The control strategies of Doubly Fed Induction Generator (DFIG) system output current unbalance and distortion suppression have been well investigated in detail, with the implementation of two kinds of resonant regulators, i.e., conventional Resonance (R) regulator or Vector Proportional Integral...... regulator (equivalent to the combination of virtual positive resistor and virtual negative inductor), i.e., better high order harmonic distortion suppression. The theoretical analysis and MATLAB simulation results have validated the correctness of this conclusion....... reshaping though the introduction of R and VPI regulator. It is pointed out that, when implemented in the DFIG system output current unbalance and distortion suppression, the VPI regulator (equivalent to the combination of virtual positive inductor and virtual positive resistor) has two advantages over R...

  5. An improved PID switching control strategy for type 1 diabetes.

    Science.gov (United States)

    Marchetti, Gianni; Barolo, Massimiliano; Jovanovic, Lois; Zisser, Howard; Seborg, Dale E

    2008-03-01

    In order for an "artificial pancreas" to become a reality for ambulatory use, a practical closed-loop control strategy must be developed and validated. In this paper, an improved PID control strategy for blood glucose control is proposed and critically evaluated in silico using a physiologic model of Hovorka et al. [1]. The key features of the proposed control strategy are: 1) a switching strategy for initiating PID control after a meal and insulin bolus; 2) a novel time-varying setpoint trajectory; 3) noise and derivative filters to reduce sensitivity to sensor noise; and 4) a practical controller tuning strategy. Simulation results demonstrate that proposed control strategy compares favorably to alternatives for realistic conditions that include meal challenges, incorrect carbohydrate meal estimates, changes in insulin sensitivity, and measurement noise.

  6. Mesh refinement strategy for optimal control problems

    Science.gov (United States)

    Paiva, L. T.; Fontes, F. A. C. C.

    2013-10-01

    Direct methods are becoming the most used technique to solve nonlinear optimal control problems. Regular time meshes having equidistant spacing are frequently used. However, in some cases these meshes cannot cope accurately with nonlinear behavior. One way to improve the solution is to select a new mesh with a greater number of nodes. Another way, involves adaptive mesh refinement. In this case, the mesh nodes have non equidistant spacing which allow a non uniform nodes collocation. In the method presented in this paper, a time mesh refinement strategy based on the local error is developed. After computing a solution in a coarse mesh, the local error is evaluated, which gives information about the subintervals of time domain where refinement is needed. This procedure is repeated until the local error reaches a user-specified threshold. The technique is applied to solve the car-like vehicle problem aiming minimum consumption. The approach developed in this paper leads to results with greater accuracy and yet with lower overall computational time as compared to using a time meshes having equidistant spacing.

  7. Adaptive slope compensation for high bandwidth digital current mode controller

    DEFF Research Database (Denmark)

    Taeed, Fazel; Nymand, Morten

    2015-01-01

    An adaptive slope compensation method for digital current mode control of dc-dc converters is proposed in this paper. The compensation slope is used for stabilizing the inner current loop in peak current mode control. In this method, the compensation slope is adapted with the variations...... in converter duty cycle. The adaptive slope compensation provides optimum controller operation in term of bandwidth over wide range of operating points. In this paper operation principle of the controller is discussed. The proposed controller is implemented in an FPGA to control a 100 W buck converter...

  8. Solar shading control strategy for office buildings in cold climate

    DEFF Research Database (Denmark)

    Karlsen, Line Røseth; Heiselberg, Per Kvols; Bryn, Ida;

    2016-01-01

    Highlights •Solar shading control strategy for office buildings in cold climate is developed. •Satisfying energy and indoor environmental performance is confirmed. •Importance of integrated evaluations when selecting shading strategy is illustrated.......Highlights •Solar shading control strategy for office buildings in cold climate is developed. •Satisfying energy and indoor environmental performance is confirmed. •Importance of integrated evaluations when selecting shading strategy is illustrated....

  9. Force Control Strategies in Hydraulically Actuated Legged Robots

    Directory of Open Access Journals (Sweden)

    Hector Montes

    2016-03-01

    Full Text Available In this contribution, several strategies of force control have been proposed to be implemented and evaluated in ROBOCLIMBER, a quadruped robot of large dimensions. A first group of strategies proposed in this paper is based on impedance control, which is intended to adapt the foot-ground contact forces according to the experimentally specified damping ratio and the undamped natural frequency. A second control strategy of interest for many practical cases is called the parallel force/position control, which has one inner loop position control and two external control loops, one of force and another of position. A third group of control strategies is the posture stabilization for ROBOCLIMBER using the feedback of the ZMP calculation and the position of its legs. Finally, a control strategy for the control of a quasi-static gait using ZMP feedback is proposed and tested by simulation.

  10. Improved Control Strategy for Microgrid Ultracapacitor Energy Storage Systems

    Directory of Open Access Journals (Sweden)

    Xiaobo Dou

    2014-12-01

    Full Text Available Ultracapacitors (UCs, with their features of high power density and high current charge-discharge, have become the best choice for dynamic power compensation to improve the stability of microgrids and are increasingly being applied in microgrids. This paper presents the control of an energy storage system (ESS based on ultracapacitors in the context of grid-connected microgrids. The ESS is composed of DC/AC and DC/DC converters tied by a dc link. An improved dynamic model for the ESS is proposed. Based on the proposed model a Proportional-Integral-Resonant (PIR DC link voltage controller is proposed to maintain the DC link voltage through the charging-discharging control of ultracapacitors, capable of working properly under all operating conditions. An extra double frequency component is injected into the UC current by a R controller to dynamically compensate for DC instantaneous power and double frequency AC instantaneous power due to unbalanced grid conditions and disturbances. This feature maintains the DC link voltage constant under unbalanced conditions and increases the degrees of freedom of the DC/AC converter and thus facilitates the application of UCs in microgrids. Simulation and experimental results verify the effectiveness of the proposed control strategy.

  11. Compound control strategy used in Electro-Mechanical Actuator (EMA)

    Science.gov (United States)

    Fu, Yongling; Yan, Meng

    2017-01-01

    This article briefly describes the overall structure of the loading test rig; establish mathematical model of loading EMA, analyze its stability, surplus force and other properties in MATLAB; propose a compound control strategy combined speed feedback, PID and feed-forward compensation based on structure invariance principle. To verify the effectiveness of the control strategy, do a co-simulation by designing a controller based on the control strategy above in MATLAB and building the EMA model in AMESim. The results show that the compound control strategy can significantly improve dynamic tracking accuracy and reduce surplus force.

  12. Energy Optimal Control Strategy of PHEV Based on PMP Algorithm

    Directory of Open Access Journals (Sweden)

    Tiezhou Wu

    2017-01-01

    Full Text Available Under the global voice of “energy saving” and the current boom in the development of energy storage technology at home and abroad, energy optimal control of the whole hybrid electric vehicle power system, as one of the core technologies of electric vehicles, is bound to become a hot target of “clean energy” vehicle development and research. This paper considers the constraints to the performance of energy storage system in Parallel Hybrid Electric Vehicle (PHEV, from which lithium-ion battery frequently charges/discharges, PHEV largely consumes energy of fuel, and their are difficulty in energy recovery and other issues in a single cycle; the research uses lithium-ion battery combined with super-capacitor (SC, which is hybrid energy storage system (Li-SC HESS, working together with internal combustion engine (ICE to drive PHEV. Combined with PSO-PI controller and Li-SC HESS internal power limited management approach, the research proposes the PHEV energy optimal control strategy. It is based on revised Pontryagin’s minimum principle (PMP algorithm, which establishes the PHEV vehicle simulation model through ADVISOR software and verifies the effectiveness and feasibility. Finally, the results show that the energy optimization control strategy can improve the instantaneity of tracking PHEV minimum fuel consumption track, implement energy saving, and prolong the life of lithium-ion batteries and thereby can improve hybrid energy storage system performance.

  13. Strategies to control odours in livestock facilities: a critical review

    Directory of Open Access Journals (Sweden)

    Y. Ubeda

    2013-11-01

    Full Text Available Odours generated in livestock buildings constitute one of the most relevant air quality issues of intensive livestock production. Reducing nuisance episodes related to odour exposure is therefore essential for a sustainable livestock production. In this study, the state-of-the-art on odour mitigation techniques in livestock housing is critically reviewed. Scientific advances in the last decade are revised and research needs are also identified. The complex nature of livestock odours is firstly reviewed and examined. Then, the most relevant odour control strategies are analyzed in terms of present knowledge and future needs. The strategies considered are: nutritional strategies, manure additives, building design, air filtration, manure covers, manure treatment systems and windbreaks. Finally, future research needs and priorities when establishing mitigation techniques are identified. Despite important recent advances, there are still some challenges for scientists, producers and regulators, particularly related to field evaluation of odours. Therefore, to control livestock odours effectively, using standardized field assessment techniques will be required. Also, investigating measurement and model errors may be useful to better understand the limitations of the current methods, as well as to identify research priorities.

  14. Current Treatment Strategies for Recurrent Urinary Tract Infections

    Directory of Open Access Journals (Sweden)

    Murat Zor

    2014-04-01

    Full Text Available Urinary tract infections (UTIs are the most common bacterial infections among all age groups. Three UTI episodes with positive culture results in a one year period are called recurrent UTIs. Recurrent UTIs are common health problems threatening physical and mental health of the individuals in all age groups. Unconscious antibiotic usages lead multi-antibiotic resistant agents. In a multidisciplinary manner the patient must be evaluated if he/she has a genetic, physiological or anatomical disorder. Several current approaches such herbal products and vaccines are increasingly used to avoid antibiotic overuse [TAF Prev Med Bull 2014; 13(2.000: 161-168

  15. Evaluation of gastrointestinal bleeding: Update of current radiologic strategies

    Institute of Scientific and Technical Information of China (English)

    Parth; J; Parekh; Ross; C; Buerlein; Rouzbeh; Shams; Harlan; Vingan; David; A; Johnson

    2014-01-01

    Gastrointestinal bleeding(GIB) is a common presenta-tion with significant associated morbidity and mortality, the prevalence of which continues to rise with the ever-increasing aging population. Initial evaluation includes an esophagoduodeonscopy and/or colonoscopy, which may fail to reveal a source. Such cases prove to be a dilemma and require collaboration between gastroen-terology and radiology in deciding the most appropriate approach. Recently, there have been a number of ra-diologic advances in the approach to GIB. The purpose of this review is to provide an evidence-based update on the most current radiologic modalities available and an algorithmic approach to GIB.

  16. Control strategies for 2-quadrant converter used in grid power flow control

    CERN Document Server

    Maestri, Sebastian; Uicich, Gustavo; Benedetti, Mario; Papastergiou, Konstantinos; Le Godec, Gilles

    2015-01-01

    This work presents the analysis of a two-quadrant regulator connected to the DC-link of a 4-quadrant magnet supply. The key objective is to present some regulation strategies for controlling the peak power required from the power network as well as to recover the magnet energy into capacitor banks. A comparative study that highlights the trade off between the size of reactive elements, and the peak current drawn from the electrical network is presented.

  17. Building Visual Artists’ Resilience Capabilities: Current Educator Strategies and Methods

    Directory of Open Access Journals (Sweden)

    Eileen Maree Siddins

    2016-07-01

    Full Text Available Enrolments in higher education programs in the creative and performing arts are increasing in many countries. Yet graduates of these degrees, who enter the broad sector known as the creative industries, face particular challenges in terms of securing long-term and sustainable employment. In addition, creative and performing artists face a range of mental challenges, caused by such factors as: the solitary nature of much creative practice, critical feedback by audiences and gatekeepers, or the general pressures associated with maintaining artistic relevance or integrity. The concepts of resilience and professional wellbeing are therefore highly relevant to those who pursue a career in creative industries, and while there has been an emerging body of work in this area, to date it has focussed on the performing arts area (e.g. music, theatre. Hence, in order to expand knowledge relevant to resilience and artists, this paper sets out to explore the extent to which current educators in the Australian context specifically address these issues within higher visual arts curricula; specifically the areas of illustration, design, film and photography. This was achieved via interviews with seventeen current academics working in these areas. The findings propose that higher education providers of programs in the visual arts consider placing a stronger emphasis on the embedded development of resilience and professional wellbeing capacities.

  18. [Electronic health strategies in The Americas: current situation and perspectives].

    Science.gov (United States)

    D Agostino, Marcelo

    2015-01-01

    The main objective of the Strategy and Plan of Action on eHealth (2012-2017) is to contribute to sustainable development of health systems of member states. Its adoption aims to improve quality and access to health services through the use of information and communication technologies (ICT), the implementation of digital literacy programs and access to quality information to advance towards more informed, equitable, competitive and democratic societies. PAHO/WHO considers that in society, free and equal access to health information should be a fundamental right of individuals. Access to information, knowledge sharing and use of information and communication technology in the health sector continues to grow and is driving significant changes in the way people interact with health services and among themselves in social networks and through the use of mobile devices (mHealth). This hyper-connected society, or information society, brings new challenges and opportunities related to the use of massive data (Big Data) that forces us to rethink our relationship with reality and the traditional ways of managing health information.

  19. Current and novel therapeutic strategies in celiac disease.

    Science.gov (United States)

    Kurada, Satya; Yadav, Abhijeet; Leffler, Daniel A

    2016-09-01

    A gluten free diet (GFD) is the only available treatment for celiac disease (CD). However many patients fail to respond fully clinically or histologically. Several surveys highlight the psychosocial implications of adherence to a GFD. Hence, efforts are ongoing to develop therapeutic strategies beyond a GFD. We conducted a search of PubMed and clinicaltrials.gov to extract articles on CD using keywords including 'celiac disease' and 'refractory celiac disease' (RCD) and focused on articles conducting pathophysiologic and therapeutic research in/ex-vivo models and human trials. We highlight novel therapeutics that manipulate these mechanisms including tight junction regulators, glutenases, gluten sequestrants and immunotherapy using vaccines, nanoparticles that may serve as adjuncts to a GFD or more ambitiously to allow for gluten consumption. We also highlight the role of anti-inflammatories, immunosuppressants and monoclonal antibodies in RCD. Expert commentary: Therapeutics including tight junction regulators, glutenases have the potential to be approved for non-responsive CD or as gluten adjuncts. We expect results of various phase 1/2 trials using AMG 714, BL 7010, IgY antibodies to be published. In the interim, off-label use of 5 amino-salicylates, budesonide, nucleoside analogues and newer biologics developed for other inflammatory diseases will be used in RCD.

  20. Osteochondral tissue engineering with biphasic scaffold: current strategies and techniques.

    Science.gov (United States)

    Shimomura, Kazunori; Moriguchi, Yu; Murawski, Christopher D; Yoshikawa, Hideki; Nakamura, Norimasa

    2014-10-01

    The management of osteoarthritis (OA) remains challenging and controversial. Although several clinical options exist for the treatment of OA, regeneration of the damaged articular cartilage has proved difficult due to the limited healing capacity. With the advancements in tissue engineering and cell-based technologies over the past decade, new therapeutic options for patients with osteochondral lesions potentially exist. This review will focus on the feasibility of tissue-engineered biphasic scaffolds, which can mimic the native osteochondral complex, for osteochondral repair and highlight the recent development of these techniques toward tissue regeneration. Moreover, basic anatomy, strategy for osteochondral repair, the design and fabrication methods of scaffolds, as well as the choice of cells, growth factor, and materials will be discussed. Specifically, we focus on the latest preclinical animal studies using large animals and clinical trials with high clinical relevance. In turn, this will facilitate an understanding of the latest trends in osteochondral repair and contribute to the future application of such clinical therapies in patients with OA.

  1. Current Strategies in Anesthesia and Analgesia for Total Knee Arthroplasty.

    Science.gov (United States)

    Moucha, Calin Stefan; Weiser, Mitchell C; Levin, Emily J

    2016-02-01

    Total knee arthroplasty is associated with substantial postoperative pain that may impair mobility, reduce the ability to participate in rehabilitation, lead to chronic pain, and reduce patient satisfaction. Traditional general anesthesia with postoperative epidural and patient-controlled opioid analgesia is associated with an undesirable adverse-effect profile, including postoperative nausea and vomiting, hypotension, urinary retention, respiratory depression, delirium, and an increased infection rate. Multimodal anesthesia--incorporating elements of preemptive analgesia, neuraxial perioperative anesthesia, peripheral nerve blockade, periarticular injections, and multimodal oral opioid and nonopioid medications during the perioperative and postoperative periods--can provide superior pain control while minimizing opioid-related adverse effects, improving patient satisfaction, and reducing the risk of postoperative complications.

  2. Control strategy of maglev vehicles based on particle swarm algorithm

    Institute of Scientific and Technical Information of China (English)

    Hui Wang; Gang Shen; Jinsong Zhou

    2014-01-01

    Taking a single magnet levitation system as the object, a nonlinear numerical model of the vehicle-guide-way coupling system was established to study the levitation control strategies. According to the similarity in dynamics, the single magnet-guideway coupling system was simpli-fied into a magnet-suspended track system, and the corre-sponding hardware-in-loop test rig was set up using dSPACE. A full-state-feedback controller was developed using the levitation gap signal and the current signal, and controller parameters were optimized by particle swarm algorithm. The results from the simulation and the test rig show that, the proposed control method can keep the sys-tem stable by calculating the controller output with the full-state information of the coupling system, Step responses from the test rig show that the controller can stabilize the system within 0.15 s with a 2% overshot, and performs well even in the condition of violent external disturbances. Unlike the linear quadratic optimal method, the particle swarm algorithm carries out the optimization with the nonlinear controlled object included, and its optimized results make the system responses much better.

  3. [Current and future diagnostic strategies in venous thromboembolic disease].

    Science.gov (United States)

    Gabriel Botella, F; Labiós Gómez, M; Brasó Aznar, J V; Llavador Ros, G; Bort Martí, J

    1999-08-01

    Thromboembolic disease (TD), which includes deep venous thrombosis (DVT) and pulmonary embolism (PE), is the most common acute cardiovascular condition after ischemic cardiopathy and stroke. It is often difficult to diagnose, as it is well-known that half of PE episodes appear are recognized while the patient is still alive and which appear in 30-40% of symptomatic patients. Nonetheless, there are two well-differentiated phases in the diagnosis of TD: the suspicion, and the diagnosis. The first is very important, and is within the competence of any physician. The second can be ratified when carrying out specific tests. We have developed successive steps in the two phases of diagnosis, we critically review the distinct parts currently implicated in the strategic diagnosis of TD. Finally, we analyze the new diagnostic techniques to substitute, possibly, angiography in many cases, and perhaps to include ventilation/perfusion (V/Q) pulmonary gammagraphy, once become generally available.

  4. Primary prevention of diabetes mellitus: current strategies and future trends

    Directory of Open Access Journals (Sweden)

    Prasanta K. Bhattacharya

    2016-04-01

    Full Text Available Aim of this paper is to find evidence for primary prevention of type-2 diabetes mellitus (T2DM from epidemiological studies and clinical trials, and the feasibility of applying these interventions in resource limited countries. T2DM, which accounts for more than nine-tenths of all diabetics, results from inadequate insulin secretion or underlying insulin resistance. The prevalence of diabetes, mainly T2DM, has increased rapidly during the last few decades worldwide. Since the genetic background is unlikely to change during this short time period, the growing epidemic of T2DM is more likely due to changes in environmental or lifestyle risk factors including obesity, physical inactivity, smoking, alcohol and stress. The scope and feasibility for primary prevention of T2DM is based on elimination of these risk factors. This evidence that T2DM is preventable comes from epidemiologic studies and clinical trials of effect of lifestyle changes and drugs in development of T2DM. The positive effects are more profound and safer with lifestyle modifications (LSM compared to medications. This is shown to be effective globally, across various ethnicities and races and sustainable on long-term follow-up. However, there is a major challenge in translating this evidence into economically viable and sustained community programs, as these LSM interventions are expensive, even from western standards point of view. Future plan should focus on health education of the public, improving the national capacity to detect and manage the environmental risks including strategies to reduce stress, and development of innovative, cost effective, and scalable methodologies.

  5. Current strategies to treat tuberculosis [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Anthony T. Podany

    2016-10-01

    Full Text Available Tuberculosis (TB has been a leading cause of death for more than a century. While effective therapies exist, treatment is long and cumbersome. TB control is complicated by the overlapping problems created by global inadequacy of public health infrastructures, the interaction of the TB and human immunodeficiency virus (HIV epidemics, and the emergence of drug-resistant TB. After a long period of neglect, there is now significant progress in the development of novel treatment regimens for TB. Focusing on treatment for active disease, we review pathways to TB regimen development and the new and repurposed anti-TB agents in clinical development.

  6. Few-View Prereconstruction Guided Tube Current Modulation Strategy Based on the Signal-to-Noise Ratio of the Sinogram

    Directory of Open Access Journals (Sweden)

    Ming Chang

    2015-01-01

    Full Text Available The radiation dose reduction without sacrificing the image quality as an important issue has raised the attention of CT manufacturers and different automatic exposure control (AEC strategies have been adopted in their products. In this paper, we focus on the strategy of tube current modulation. It is deduced based on the signal-to-noise (SNR of the sinogram. The main idea behind the proposed modulation strategy is to keep the SNR of the sinogram proximately invariable using the few-view reconstruction as a good reference because it directly affects the noise level of the reconstructions. The numerical experiment results demonstrate that, compared with constant tube current, the noise distribution is more uniform and the SNR and CNR of the reconstruction are better when the proposed strategy is applied. Furthermore it has the potential to distinguish the low-contrast target and to reduce the radiation dose.

  7. Research on Full-Digital Hysteresis Current Controlled Controllable Current Source%全数字滞环电流控制可控电流源研究

    Institute of Scientific and Technical Information of China (English)

    单任仲; 沈沉; 陈来军; 刘锋; 黄秀琼

    2012-01-01

    Based on field-programmable gate array (FPGA), a full-digital hysteresis current controlled controllable current disturbance source, in which the single-phase full-bridge topology is chosen as the main circuit of the controllable current source, is proposed. Simulation analysis of bi-level and tri-level hysteresis current control is performed and simulation results are compared. Utilizing self-defined module in PSCAD software two different control strategies are programmed by Fortran language, and simulation results of the two control strategies show that the bi-level hysteresis current control is more suitable to controllable current source. Finally, a principle prototype is designed and made, and then the control of current source is implemented by FPGA controller and the hysteresis current control is implemented by VHDL programming. Experimental results show that the hysteresis current control technique is effective for the implementation of controllable current source.%提出了一种基于现场可编程门阵列(field-programm-able gate array,FPGA)控制的全数字滞环电流控制型可控电流扰动源,选取单相全桥拓扑作为可控电流源的主电路结构.对两态滞环和三态滞环电流控制进行了仿真分析和对比,利用PSCAD软件中的自定义模块,采用Fortran语言对2种不同控制策略进行编程实现,仿真结果表明两态滞环电流控制策略更加适合于可控电流源.最后设计制作了一台原理样机,利用FPGA控制器实现了对电流源的控制,采用VHDL语言实现滞环电流控制,实验结果表明滞环电流控制技术对可控电流源的实现是有效的.

  8. Pwm Control Strategy For Controlling Of Parallel Rectifiers In Single Phase To Three Phase Drive System

    Directory of Open Access Journals (Sweden)

    Ramakrishna Manohar Anaparthi

    2014-12-01

    Full Text Available This paper explains that how to develop and design, control of single phase to three phase drive system. The proposed topology of drive system consisting of two parallel connected rectifiers, inverter and induction motor, connected through inductor and capacitor, where used to produce balanced output to the motor drive. The main objective of this proposed method is to reduce the circulating currents and harmonic distortions at the converter input side, here the control strategy of drive system is PWM (pulse width modulations techniques control strategy, the proposed topology also provides fault compensation in the case of short circuit faults and failure of switches for uninterrupted Power supplies. We also develop and simulate the MATLAB models for proposed drive system, by using MATLAB/ Simulink the output results simulate and observed.

  9. Current imaging strategies for the evaluation of uterine cervical cancer.

    Science.gov (United States)

    Bourgioti, Charis; Chatoupis, Konstantinos; Moulopoulos, Lia Angela

    2016-04-28

    Uterine cervical cancer still remains an important socioeconomic issue because it largely affects women of reproductive age. Prognosis is highly depended on extent of the disease at diagnosis and, therefore, accurate staging is crucial for optimal management. Cervical cancer is clinically staged, according to International Federation of Gynecology and Obstetrics guidelines, but, currently, there is increased use of cross sectional imaging modalities [computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography-CT (PET-CT)] for the study of important prognostic factors like tumor size, parametrial invasion, endocervical extension, pelvic side wall or adjacent/distal organs involvement and lymph node status. Imaging indications also include cervical cancer follow-up, evaluation of tumor response to treatment and selection of suitable candidates for less radical surgeries like radical trachelectomy for fertility preservation. The preferred imaging method for local cervical cancer evaluation is MRI; CT is equally effective for evaluation of extrauterine spread of the disease. PET-CT shows high diagnostic performance for the detection of tumor relapse and metastatic lymph nodes. The aim of this review is to familiarize radiologists with the MRI appearance of cervical carcinoma and to discuss the indications of cross sectional imaging during the course of the disease in patients with cervical carcinoma.

  10. The presentation, pathology, and current management strategies of cutaneous metastasis

    Directory of Open Access Journals (Sweden)

    Christina Yin Bin Wong

    2013-01-01

    Full Text Available Skin metastases are rare in the routine clinical practice of dermatology, but are of major clinical significance because they usually indicate advanced disease. We reviewed the literature on skin metastasis regarding recent trends in clinical presentation and diagnosis of the most common cutaneous lesions. An extensive literature review was conducted using PubMed from May 26, 2011 to July 16, 2013 relating cutaneous metastases. Articles chosen for reference were queried with the following prompts: "Cutaneous metastases", "clinical presentation", "histological features", and "immunohistochemistry". Further searches included "treatment" and "management" options for "metastatic breast", "metastatic colorectal", "metastatic melanoma", "metastatic lung", and "hematologic cancers." We also reviewed the literature on the current management of melanoma as a model for all cutaneous metastatic disease. Our own clinical findings are presented and compared to the literature. Additionally, we highlight the most useful immunohistochemical studies that aid in diagnoses. Several novel therapies and combination therapies such as electrochemotherapy, vemurafenib, and imiquimod will be discussed for palliative treatment of cancers that have been found to improve cutaneous lesions. We review these notable findings and developments regarding skin metastases for the general dermatologist.

  11. Current imaging strategies for the evaluation of uterine cervical cancer

    Institute of Scientific and Technical Information of China (English)

    Charis Bourgioti; Konstantinos Chatoupis; Lia Angela Moulopoulos

    2016-01-01

    Uterine cervical cancer still remains an important socioeconomic issue because it largely affects women of reproductive age.Prognosis is highly depended on extent of the disease at diagnosis and,therefore,accurate staging is crucial for optimal management.Cervical cancer is clinically staged,according to International Federation of Gynecology and Obstetrics guidelines,but,currently,there is increased use of cross sectional imaging modalities [computed tomography(CT),magnetic resonance imaging(MRI),positron emission tomography-CT(PET-CT)] for the study of important prognostic factors like tumor size,parametrial invasion,endocervical extension,pelvic side wall or adjacent/distal organs involvement and lymph node status.Imaging indications also include cervical cancer follow-up,evaluation of tumor response to treatment and selection of suitable candidates for less radical surgeries like radical trachelectomy for fertility preservation.The preferred imaging method for local cervical cancer evaluation is MRI;CT is equally effective for evaluation of extrauterine spread of the disease.PETCT shows high diagnostic performance for the detection of tumor relapse and metastatic lymph nodes.The aim of this review is to familiarize radiologists with the MRI appearance of cervical carcinoma and to discuss the indications of cross sectional imaging during the course of the disease in patients with cervical carcinoma.

  12. Paratransgenesis: a promising new strategy for mosquito vector control.

    Science.gov (United States)

    Wilke, André Barretto Bruno; Marrelli, Mauro Toledo

    2015-06-24

    The three main mosquito genera, Anopheles, Aedes and Culex, transmit respectively malaria, dengue and lymphatic filariasis. Current mosquito control strategies have proved unsuccessful, and there still is a substantial number of morbidity and mortality from these diseases. Genetic control methods have now arisen as promising alternative strategies, based on two approaches: the replacement of a vector population by disease-refractory mosquitoes and the release of mosquitoes carrying a lethal gene to suppress target populations. However, substantial hurdles and limitations need to be overcome if these methods are to be used successfully, the most significant being that a transgenic mosquito strain is required for every target species, making genetically modified mosquito strategies inviable when there are multiple vector mosquitoes in the same area. Genetically modified bacteria capable of colonizing a wide range of mosquito species may be a solution to this problem and another option for the control of these diseases. In the paratransgenic approach, symbiotic bacteria are genetically modified and reintroduced in mosquitoes, where they express effector molecules. For this approach to be used in practice, however, requires a better understanding of mosquito microbiota and that symbiotic bacteria and effector molecules be identified. Paratransgenesis could prove very useful in mosquito species that are inherently difficult to transform or in sibling species complexes. In this approach, a genetic modified bacteria can act by: (a) causing pathogenic effects in the host; (b) interfering with the host's reproduction; (c) reducing the vector's competence; and (d) interfering with oogenesis and embryogenesis. It is a much more flexible and adaptable approach than the use of genetically modified mosquitoes because effector molecules and symbiotic bacteria can be replaced if they do not achieve the desired result. Paratransgenesis may therefore become an important integrated

  13. Fuzzy Control Strategies in Human Operator and Sport Modeling

    CERN Document Server

    Ivancevic, Tijana T; Markovic, Sasa

    2009-01-01

    The motivation behind mathematically modeling the human operator is to help explain the response characteristics of the complex dynamical system including the human manual controller. In this paper, we present two different fuzzy logic strategies for human operator and sport modeling: fixed fuzzy-logic inference control and adaptive fuzzy-logic control, including neuro-fuzzy-fractal control. As an application of the presented fuzzy strategies, we present a fuzzy-control based tennis simulator.

  14. Improving epidemic control strategies by extended detection

    Science.gov (United States)

    Karp, Paweł; Dybiec, Bartłomiej; Kleczkowski, Adam

    2014-11-01

    Majority of epidemics eradication programs work in preventive responsive way. The lack of exact information about epidemiological status of individuals makes responsive actions less efficient. Here, we demonstrate that additional tests can significantly increase the efficiency of "blind" treatment (vaccination or culling). Eradication strategy consisting of "blind" treatment in very limited local neighborhood supplemented by extra tests in a little bit larger neighborhood is able to prevent invasion of even highly infectious diseases and to achieve this at a cost lower than for the "blind" strategy. The effectiveness of the extended strategy depends on such parameters as the test efficiency and test cost.

  15. Current and emerging treatment strategies for vertebral compression fractures

    Directory of Open Access Journals (Sweden)

    Hacein-Bey L

    2012-05-01

    Full Text Available Lotfi Hacein-BeyRadiological Associates of Sacramento Medical Group Inc, Sacramento, CA, USABackground: Vertebral compression fractures are most commonly related to osteoporosis or cancer, both of which are on the rise throughout the world. Once a vertebra is fractured, gradual deterioration of quality of life due to crippling pain and spinal instability usually follows. Although a number of traditional management options have been available to promote pain relief and to allow for increased activities, such as bed rest, bracing, pain medications, and light exercise programs, these have limited effectiveness in the majority of patients. Over 20 years ago, percutaneous vertebroplasty, which is a minimally invasive procedure consisting of the injection of polymethylmethacrylate directly into the fractured vertebra, emerged as an effective treatment. Various vertebral augmentation procedures were subsequently designed, all of which aim at eliminating pain, limiting or reversing vertebral collapse, and providing stability to the affected segment of the spine.Objective: This article discusses clinical aspects of vertebral compression fractures, current indications and contraindications and summarizes technical aspects of vertebroplasty, kyphoplasty, lordoplasty, and device-implanting vertebral augmentation procedures. Treatment effectiveness, which is significant despite recent criticism of vertebroplasty and other vertebral augmentation procedures, is also discussed. As economic pressures on health care systems are increasing in all countries, it is expected that the appropriateness, clinical effectiveness, and cost-effectiveness of vertebral augmentation procedures will be increasingly established by outcome analyses.Conclusion: It is important that physicians are familiar with vertebroplasty and other procedures designed to treat vertebral fractures in patients with advanced osteoporosis or cancer. These fractures, which are common and often

  16. Engine control strategy for a series hybrid electric vehicle incorporating load-leveling and computer controlled energy management

    Energy Technology Data Exchange (ETDEWEB)

    Hochgraf, C.G.; Ryan, M.J.; Wiegman, H.L. [Univ. of Wisconsin, Madison, WI (United States)

    1996-09-01

    This paper identifies important engine, alternator and battery characteristics needed for determining an appropriate engine control strategy for a series hybrid electric vehicle. Examination of these characteristics indicates that a load-leveling strategy applied to the small engine will provide better fuel economy than a power-tracking scheme. An automatic energy management strategy is devised whereby a computer controller determines the engine-alternator turn-on and turn-off conditions and controls the engine-alternator autonomously. Battery state of charge is determined from battery voltage and current measurements. Experimental results of the system`s performance in a test vehicle during city driving are presented.

  17. Hysteretic Current Controlled Zvs Dc/Dc Converter For Automobile

    DEFF Research Database (Denmark)

    Cernat, M.; Scortarul, P.; Tanase, A.

    2007-01-01

    A novel bi-directional dc-dc converter with ZVS and interleaving for dual voltage systems in automobiles is presented. A variable frequency extended band hysteretic current control method is proposed. In comparison with classical fixed frequency current control PWM, the reverse polarity peak curr...

  18. Improved Control Strategy for DFIG Wind Turbines for Low Voltage Ride Through

    Directory of Open Access Journals (Sweden)

    Chanxia Zhu

    2013-02-01

    Full Text Available This paper presents an improved control strategy for both the rotor side converter (RSC and grid side converter (GSC of a doubly fed induction generator (DFIG-based wind turbine (WT system to enhance the low voltage ride through (LVRT capability. Within the proposed control strategy, the RSC control introduces transient feed-forward compensation terms to mitigate the high frequency harmonic components and reduce the surge in the rotor currents. The proposed GSC control scheme also introduces a compensation term reflecting the instantaneous variation of the output power of the rotor side converter with consideration of the instantaneous power of grid filter impendence to keep the dc-link voltage nearly constant during the grid faults. To provide precise control, non-ideal proportional resonant (PR controllers for both the RSC and GSC current regulation are employed to further improve dynamic performance. Simulations performed in Matlab/Simulink verify the effectiveness of the proposed control strategy.

  19. A Control Strategy for Single-phase Grid-Connected Inverter with Power Quality Regulatory Function

    Directory of Open Access Journals (Sweden)

    Luo Ling

    2013-07-01

    Full Text Available A single-phase grid-connected inverter system based on LCL filter is established,which combines the features of inverter and active power filter. A composite control strategy for grid-connected inverter with the function of implementing reactive power compensation and harmonic compensation in the grid-connected power generation is proposed. Firstly, grid-connected inverter system structure and model is analyzed. A quasi-Proportional Resonant control method to gain the control of grid-connected fundamental wave current containing reactive power compensation current as well as the control of harmonic compensation currents is put forward; then the calculation methods of  composite control command current based on both second order generalized integrator-quadrature signal generator (SOGI-QSG and instantaneous reactive power theory are given. Finally, the effectiveness of the control strategy proposed in this paper is verified by simulation.

  20. Application of a controllable degron strategy for metabolic engineering

    DEFF Research Database (Denmark)

    Knuf, Christoph; Maury, Jerome; Jacobsen, Simo Abdessamad;

    2014-01-01

    , as the existing enzyme will still be active. We present a strategy for down-regulation that acts on the protein level and which can therefore be controlled in a more precise manner than the hitherto reported strategies. As a case study we show the action of the degron strategy for controlling the pools...... terpenoids, can be produced from intermediates of this pathway. Different strategies have been applied in order to down-regulate the expression of enzymes involved in the mevalonate pathway. All these strategies work on the transcriptional level. This leads to a delay of the actual regulation...

  1. Pain coping strategies predict perceived control over pain.

    Science.gov (United States)

    Haythornthwaite, J A; Menefee, L A; Heinberg, L J; Clark, M R

    1998-07-01

    Perceptions of control over pain and specific pain coping strategies are associated with a number of positive outcomes in patients with chronic pain conditions. Transactional models of stress have emphasized coping as a process that is both determined by, and influences appraisals of control. While perceptions of control and coping efforts are associated with better adjustment, little is known about the specific coping strategies that contribute to perceptions that pain is controllable. One hundred and ninety-five (65% female) individuals with chronic pain conditions admitted to an inpatient unit completed the Multidimensional Pain Inventory, the Survey of Pain Attitudes and the Coping Strategies Questionnaire. Stepwise multiple regression analyses were used to predict perceived pain control from measures of pain severity and coping. After controlling for pain severity and education, coping self-statements and reinterpreting pain sensations predicted greater perceptions of control over pain, whereas ignoring pain sensations predicted lower perceptions of control over pain. The coping strategies did not interact with pain severity in predicting perceptions of control. Coping flexibility, or the number of pain coping strategies reported at a high frequency, also predicted perceptions of control over pain and did not interact with pain severity. The present findings suggest that, regardless of pain severity, the use of specific cognitive pain coping strategies may increase perceptions of control over pain. Since the existing coping literature largely identifies maladaptive pain coping strategies, it is especially critical to establish which pain coping strategies are adaptive. Specific cognitive strategies, particularly coping self statements, are important components for cognitive-behavioral interventions for chronic pain management. Future research will need to determine whether other adaptive cognitive strategies such as reinterpreting pain sensations can be

  2. Measles: Current Status and Outbreak Control on Campus.

    Science.gov (United States)

    Amler, Robert W.; Orenstein, Walter A.

    1984-01-01

    The current effort to eliminate measles in the United States has caused record low levels of the disease. This strategy must continue to be applied in order to break the transmission of measles on college campuses through high immunization levels, promotion of rapid reporting of cases, and quick responses to outbreaks. (Author/DF)

  3. A control strategy for PV stand-alone applications

    Science.gov (United States)

    Slouma, S.; Baccar, H.

    2015-04-01

    This paper proposes a stand-alone photovoltaic (PV) system study in domestic applications. Because of the decrease in power of photovoltaic module as a consequence of changes in solar radiation and temperature which affect the photovoltaic module performance, the design and control of DC-DC buck converter was proposed for providing power to the load from a photovoltaic source.In fact, the control of this converter is carried out with integrated MPPT (Maximum Power Point Tracking) algorithm which ensures a maximum energy generated by the PV arrays. Moreover, the output stage is composed by a battery energy storage system, dc-ac inverter, LCL filter which enables higher efficiency, low distortion ac waveforms and low leakage currents. The control strategy adopted is cascade control composed by two regulation loops.Simulations performed with PSIM software were able to validate the control system.The realization and testing of the photovoltaic system were achieved in the Photovoltaic laboratory of the Centre for Research and Energy Technologies at the Technopark Borj Cedria. Experimental results verify the effeciency of the proposed system.

  4. Control strategies for afterload reduction with an artificial vasculature device.

    Science.gov (United States)

    Giridharan, Guruprasad A; Cheng, Rolando Chip; Glower, Jacob S; Ewert, Daniel L; Sobieski, Michael A; Slaughter, Mark S; Koenig, Steven C

    2012-01-01

    Ventricular assist devices (VADs) have been used successfully as a bridge to transplant in heart failure patients by unloading ventricular volume and restoring the circulation. An artificial vasculature device (AVD) is being developed that may better facilitate myocardial recovery than VAD by controlling the afterload experienced by the native heart and controlling the pulsatile energy entering into the arterial system from the device, potentially reconditioning the arterial system properties. The AVD is a valveless, 80 ml blood chamber with a servo-controlled pusher plate connected to the ascending aorta by a vascular graft. Control algorithms for the AVD were developed to maintain any user-defined systemic input impedance (IM) including resistance, elastance, and inertial components. Computer simulation and mock circulation models of the cardiovascular system were used to test the efficacy of two control strategies for the AVD: 1) average impedance position control (AIPC)-to maintain an average value of resistance during left ventricular (LV) systole and 2) instantaneous impedance force feedback (IIFF) and position control (IIPC)-to maintain a desired value or profile of resistance and compliance. Computer simulations and mock loop tests were performed to predict resulting cardiovascular pressures, volumes, flows, and the resistance and compliance experienced by the native LV during ejection for simulated normal, failing, and recovering LV. These results indicate that the LV volume and pressure decreased, and the LV stroke volume increased with decreasing IM, resulting in an increased ejection fraction. Although the AIPC algorithm is more stable and can tolerate higher levels of sensor errors and noise, the IIFF and IIPC control algorithms are better suited to maintain any instantaneous IM or an IM profile. The developed AVD impedance control algorithms may be implemented with current VADs to promote myocardial recovery and facilitate weaning.

  5. Model Predictive Current Control for High-Power Grid-Connected Converters with Output LCL Filter

    DEFF Research Database (Denmark)

    Delpino, Hernan Anres Miranda; Teodorescu, Remus; Rodriguez, Pedro

    2009-01-01

    A model predictive control strategy for a highpower, grid connected 3-level neutral clamped point converter is presented. Power losses constraints set a limit on commutation losses so reduced switching frequency is required, thus producing low frequency current harmonics. To reduce these harmonics...... an LCL filter is used. The proposed control strategy allows control of the active and reactive power fed into the grid, reduce the switching frequency within acceptable operational margins and keep balance of the DC-link capacitor voltages while avoiding excitation of the filter resonance frequencies....

  6. Agent-based Cyber Control Strategy Design for Resilient Control Systems: Concepts, Architecture and Methodologies

    Energy Technology Data Exchange (ETDEWEB)

    Craig Rieger; Milos Manic; Miles McQueen

    2012-08-01

    The implementation of automated regulatory control has been around since the middle of the last century through analog means. It has allowed engineers to operate the plant more consistently by focusing on overall operations and settings instead of individual monitoring of local instruments (inside and outside of a control room). A similar approach is proposed for cyber security, where current border-protection designs have been inherited from information technology developments that lack consideration of the high-reliability, high consequence nature of industrial control systems. Instead of an independent development, however, an integrated approach is taken to develop a holistic understanding of performance. This performance takes shape inside a multiagent design, which provides a notional context to model highly decentralized and complex industrial process control systems, the nervous system of critical infrastructure. The resulting strategy will provide a framework for researching solutions to security and unrecognized interdependency concerns with industrial control systems.

  7. Steady-State Analysis and Comparison of Control Strategies for PMSM

    Directory of Open Access Journals (Sweden)

    Jyoti Agrawal

    2015-01-01

    Full Text Available Permanent Magnet Synchronous Motor (PMSM has been considered as the best choice for numerous applications. To make PMSM a high performance drive, effective control system is required. Vector control is accepted widely due to its decoupling effect but it is not the only performance requirement. Additional control methods such as constant torque angle control (CTAC, optimum torque per ampere control (OTPAC, unity power factor control (UPFC, constant mutual flux linkages control (CMFLC, and angle control of air gap flux and current phasor (ACAGF can also be implemented. This paper therefore presents some important control strategies for PMSM along with merits and limitations which provide a wide variety of control choices in many applications. The performance characteristics for each strategy under steady state are modelled and simulated in MATLAB environment. Based on the simulation results, a conclusion is drawn that OTPAC is superior in normalized torque per unit normalized stator current (Ten/isn ratio whereas UPFC yields very low Ten/isn ratio. In addition, performances of these control strategies are compared, which is a key to select optimum strategy depending on requirements. Based on the comparative study, it can be concluded that CMFLC is superior to CTAC, ACAGF, OTPAC, and UPFC. Hence, it can be a good control strategy to consider.

  8. 40 CFR 52.573 - Control strategy: General.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: General. 52.573... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Georgia> § 52.573 Control strategy: General. The generic rules and procedures for emission trades (bubbles), submitted on October 27, 1982, by...

  9. 40 CFR 52.1582 - Control strategy and regulations: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy and regulations: Ozone... Control strategy and regulations: Ozone. (a) Subchapter 16 of the New Jersey Administrative Code, entitled... of the 1990 Clean Air Act. (d)(1) The base year ozone precursor emission inventory requirement...

  10. 40 CFR 52.350 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.350 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.350 Control strategy: Ozone. (a) Revisions to the Colorado State Implementation Plan, 1-hour ozone NAAQS Redesignation Request and...

  11. 40 CFR 52.377 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.377 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Connecticut § 52.377 Control strategy: Ozone. (a... requirements of sections 172(c)(9) and 182(c)(9) of the Clean Air Act, for the Greater Hartford serious...

  12. 40 CFR 52.930 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.930 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Kentucky § 52.930 Control strategy: Ozone. (a) The VOC..., Campbell and Kenton Counties) ozone nonattainment area. The demonstration of attainment of the...

  13. 40 CFR 52.66 - Control Strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control Strategy: Ozone. 52.66 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Alabama § 52.66 Control Strategy: Ozone. (a) The redesignation request submitted by the State of Alabama, on March 16, 1995 for the Birmingham marginal...

  14. 40 CFR 52.476 - Control strategy: ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: ozone. 52.476 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS District of Columbia § 52.476 Control strategy: ozone. (a... of Progress Plan for the District of Columbia's portion of the Metropolitan Washington, D.C....

  15. 40 CFR 52.582 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.582 Section 52.582 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Georgia> § 52.582 Control strategy: Ozone. (a)...

  16. 40 CFR 52.1375 - Control strategy: Lead.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Lead. 52.1375 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Montana § 52.1375 Control strategy: Lead. Determination—EPA has determined that the East Helena Lead nonattainment area has attained the lead national...

  17. 40 CFR 52.2236 - Control strategy; lead.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy; lead. 52.2236 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Tennessee § 52.2236 Control strategy; lead... on October 6, 1994. These revisions address the requirements necessary to change a lead nonattainment...

  18. 40 CFR 52.58 - Control strategy: Lead.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: Lead. 52.58 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Alabama § 52.58 Control strategy: Lead. The lead plan... the lead standard throughout Alabama. The lead plan submitted by the State on October 7, 1985, and...

  19. 40 CFR 52.1681 - Control strategy: Lead.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Lead. 52.1681 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) New York § 52.1681 Control strategy: Lead. As part of the attainment demonstration for lead, the State of New York has committed to rate all sources...

  20. 40 CFR 52.378 - Control strategy: PM10

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: PM10 52.378 Section 52.378 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Connecticut § 52.378 Control strategy: PM10 (a)...

  1. Controlling ultrafast currents by the non-linear photogalvanic effect

    CERN Document Server

    Wachter, Georg; Lemell, Christoph; Tong, Xiao-Min; Yabana, Kazuhiro; Burgdörfer, Joachim

    2015-01-01

    We theoretically investigate the effect of broken inversion symmetry on the generation and control of ultrafast currents in a transparent dielectric (SiO2) by strong femto-second optical laser pulses. Ab-initio simulations based on time-dependent density functional theory predict ultrafast DC currents that can be viewed as a non-linear photogalvanic effect. Most surprisingly, the direction of the current undergoes a sudden reversal above a critical threshold value of laser intensity I_c ~ 3.8*10^13 W/cm2. We trace this switching to the transition from non-linear polarization currents to the tunneling excitation regime. We demonstrate control of the ultrafast currents by the time delay between two laser pulses. We find the ultrafast current control by the non-linear photogalvanic effect to be remarkably robust and insensitive to laser-pulse shape and carrier-envelope phase.

  2. SIMULATION AND IMPLEMENTATION OF CURRENT CONTROL OF BRUSHLESS DC MOTOR BASED ON A COMMON DC SIGNAL

    Directory of Open Access Journals (Sweden)

    J.Karthikeyan

    2010-06-01

    Full Text Available The objective of this project is to build a simple current controlled modulation technique for brushless dc motors. In electric traction and most other applications, a wide range of speed and torque control of the electric motor is required. The dc machine fulfills these requirements, but the dc machine requires constant maintenance. But the brushless permanent magnet motors do not have brushes and so they require less maintenance only. Brushless dc motors are widely used in applications which require wide range of speed and torque control because of its low inertia, fast response, high reliability and maintenance free. This current controlled technique is based on the generation of quasi- square wave currents using only one controller for the three phases. The current control strategy uses a triangular carrier for the power transistors which is simpler and more accuratethan any other options. The advantages of this technique are: a The stator currents are completely characterized by their maximum amplitude , b The three phases are controlled with the same dc component , and then the phase currents are kept at exactly the same magnitude I max, c The dc link current measurement is not required .d phase currents are kept balanced and phase over currents are eliminated.

  3. The blunt liver trauma: Review of current diagnostic and management strategies

    Directory of Open Access Journals (Sweden)

    Doklestic Krstina

    2013-12-01

    Full Text Available The liver is one of the most commonly injured organs in blunt abdominal trauma. Major liver trauma in polytraumatic patients accounts for significant morbidity and mortality. Therapeutic options for blunt hepatic trauma include both non-operative and operative management. Hemodynamic status, not the grade of the injury, should dictate the management. CT scan of the abdomen and pelvis is a standard diagnostic modality in hemodynamically stable trauma patients. Recent advancements in imaging studies and enhanced critical care strategies have shifted the paradigm for the management of liver injuries. Nonoperative management of both low- and high-grade injuries can be successful in hemodynamically stable patients. Direct suture of bleeding vessels, vascular isolation of the liver, and damage control surgery have improved outcomes in the hemodynamically unstable patients. We have reviewed current position in the treatment of blunt hepatic trau

  4. Building an information security strategy for EHR: guidelines for assessing the current situation.

    Science.gov (United States)

    Mohammad, Yara; Stergioulas, Lampros

    2010-01-01

    This paper is looking at electronic health record (EHR) systems and their information security strategy. It focuses on the first step of building an information security strategy which is analysing the current situation of an EHR system. This research is based on different research methods applied to different EHR systems. In this paper we define eight elements that can be used as guidelines for how best to assess the current situation of any EHR system.

  5. Complex state variable- and disturbance observer-based current controllers for AC drives

    DEFF Research Database (Denmark)

    Dal, Mehmet; Teodorescu, Remus; Blaabjerg, Frede

    2013-01-01

    , extracted by a disturbance observer and then injected into the current controller. In this study, a revised version of a disturbance observer-based controller and a well known complex variable model-based design with a single set of complex pole are compared in terms of design aspects and performance...... of the parameter and the cross-coupling effect. Moreover, it provides a better performance, smooth and low noisy operation with respect to the complex variable controller....... of the stator current. In order to improve the current control performance an alternative current control strategy was proposed previously aiming to avoid the undesired cross-coupling and non-linearities between the state variables. These effects are assumed as disturbances arisen in the closed-loop path...

  6. A PAC Based Current Feedforward Control for Three-Phase PWM Voltage-Type Converter

    Institute of Scientific and Technical Information of China (English)

    屈克庆; 陈国呈; 孙承波

    2004-01-01

    This paper presents a novel current feedforward control strategy for a three-phase pulse-width modulation (PWM) DC voltage-type converter based on phase and amplitude control (PAC). With right-angle triangle relation of phasors and principle of conservation of energy, a phasor adjustment method and the relevant low-frequency mathematical model of the system are analyzed in detail, both in rectification and regeneration modes for the converter, are discussed. For improving the traditional PAC dynamic performance, variable load current is detected indirectly by the change of the DC voltage, which is fed to the control system as an additional control variable to generate modulation index and phase angle. Also, the algorithm is derived and the system principle is introduced. Experimental results from a 3 kw laboratory device are included to demonstrate the effectiveness of the proposed control strategy.

  7. Discrete-Time LPV Current Control of an Induction Motor

    DEFF Research Database (Denmark)

    Bendtsen, Jan Dimon; Trangbæk, Klaus

    2003-01-01

    further complications. The synthesis method is applied to the model, yielding an LPV discrete-time controller. Finally, the efficiency of the control scheme is validated via simulations as well as on the actual induction motor, both in open-loop current control and when an outer speed control loop......In this paper we apply a new method for gain-scheduled output feedback control of nonlinear systems to current control of an induction motor. The method relies on recently developed controller synthesis results for linear parameter-varying (LPV) systems, where the controller synthesis is formulated...... as a set of linear matrix inequalities with full-block multipliers. A standard nonlinear model of the motor is constructed and written on LPV form. We then show that, although originally developed in continuous time, the controller synthesis results can be applied to a discrete-time model as well without...

  8. Discrete-Time LPV Current Control of an Induction Motor

    DEFF Research Database (Denmark)

    Bendtsen, Jan Dimon; Trangbæk, Klaus

    2003-01-01

    In this paper we apply a new method for gain-scheduled output feedback control of nonlinear systems to current control of an induction motor. The method relies on recently developed controller synthesis results for linear parameter-varying (LPV) systems, where the controller synthesis is formulated...... as a set of linear matrix inequalities with full-block multipliers. A standard nonlinear model of the motor is constructed and written on LPV form. We then show that, although originally developed in continuous time, the controller synthesis results can be applied to a discrete-time model as well without...... further complications. The synthesis method is applied to the model, yielding an LPV discrete-time controller. Finally, the efficiency of the control scheme is validated via simulations as well as on the actual induction motor, both in open-loop current control and when an outer speed control loop...

  9. Adaptive Current Control Method for Hybrid Active Power Filter

    Science.gov (United States)

    Chau, Minh Thuyen

    2016-09-01

    This paper proposes an adaptive current control method for Hybrid Active Power Filter (HAPF). It consists of a fuzzy-neural controller, identification and prediction model and cost function. The fuzzy-neural controller parameters are adjusted according to the cost function minimum criteria. For this reason, the proposed control method has a capability on-line control clings to variation of the load harmonic currents. Compared to the single fuzzy logic control method, the proposed control method shows the advantages of better dynamic response, compensation error in steady-state is smaller, able to online control is better and harmonics cancelling is more effective. Simulation and experimental results have demonstrated the effectiveness of the proposed control method.

  10. Extending satisficing control strategy to slowly varying nonlinear systems

    Science.gov (United States)

    Binazadeh, T.; Shafiei, M. H.

    2013-04-01

    Based on the satisficing control strategy, a novel approach to design a stabilizing control law for nonlinear time varying systems with slowly varying parameters (slowly varying systems) is presented. The satisficing control strategy has been originally introduced for time-invariant systems; however, this technique does not have any stability proof for time varying systems. In this paper, first, a parametric version of the satisficing control strategy is developed. Then, by considering the time as a frozen parameter, the parametric satisficing control strategy is utilized. Finally, a theorem is presented which suggested a stabilizing satisficing control law for the slowly varying control systems. Moreover, in this theorem, the maximum admissible rate of change of the system dynamics is evaluated. The efficiency of the proposed approach is demonstrated by a computer simulation.

  11. Current strategies for preventing the recurrence of hepatocellular carcinoma after liver transplantation

    Institute of Scientific and Technical Information of China (English)

    Zhuo-Yi Wang; Lei Geng; Shu-Sen Zheng

    2015-01-01

    BACKGROUND:Liver transplantation is the optimal treat-ment for a selected group of patients with moderate to severe cirrhosis and hepatocellular carcinoma (HCC). Despite the strict selection of candidates, post-transplant recurrence often occurs and markedly reduces the long-term survival of patients with HCC. The present review focuses on the current strategies on preventing the recurrence of HCC after liver transplantation. DATA SOURCES:Relevant articles were identiifed by exten-sive searching of PubMed using the keywords "hepatocellular carcinoma", "recurrence" and "liver transplantation" between January 1996 and January 2014. Additional papers were searched manually from the references in key articles. RESULTS:The current theories of HCC recurrence after liver transplantation are: (i) the growth of pre-transplant occult metastases; (ii) the engraftment of circulating tumor cells re-leased at the time of transplantation. Pre-transplant treatment aims to control local tumor by radiofrequency ablation, tran-sarterial embolization and transarterial chemoembolization. The main objective during the operation is to prevent tumor cell dissemination. Post-transplant treatment includes sys-temic anticancer therapy, antiviral therapy, and most recently, immunotherapy. These strategies concentrate on the control of the tumor when the patients are waiting for transplant, to reduce the release of HCC cells during surgical procedures and to clear the occult HCC cells after transplantation. CONCLUSIONS:Much can be done to prevent HCC recurrence after liver transplantation. In future, effort is likely to be di-rected towards combining multidisciplinary approaches and various treatment modalities.

  12. Control Strategies for Guided Collective Motion

    Science.gov (United States)

    2015-01-30

    Proceedings of the American Control Conference , Washington...of multiple robots using a modified Kuramoto model. Proceedings of the American Control Conference , Washington, DC, USA, pages 6138– 6144. 2014 ACODS...L.B. Arranz, A. Seuret, and C.C. de Wit, “Contraction control of a fleet circular formation of AUVs under limited communication range,” Proceedings of the American Control

  13. Improved Four-Switch BLDCM Direct Current Control

    Directory of Open Access Journals (Sweden)

    Pan Lei

    2013-08-01

    Full Text Available The main purpose of this study is to describe a low cost four-switch brushless dc motor (BLDCM drive. An improved direct current controlled scheme is designed and implemented to produce the desired dynamic and static current and speed characteristics. Eight voltage vectors are summarized, which are selected to control BLDCM in SVPWM pattern. This method avoids the undesired current distortion which is caused by uncontrollable phase. The operational principle of the four-switch BLDC motor drive and the developed control scheme are theoretically analyzed and the performance is demonstrated by both simulation and experimental results.

  14. Eddy current quality control of soldered current-carrying busbar splices of superconducting magnets

    CERN Document Server

    Kogan, L; Savary, F; Principe, R; Datskov, V; Rozenfel'd, E; Khudjakov, B

    2015-01-01

    The eddy current technique associated with a U-shaped transducer is studied for the quality control of soldered joints between superconducting busbars ('splices'). Two other quality control techniques, based on X-rays and direct measurement of the electrical resistance, are also studied for comparison. A comparative analysis of the advantages and disadvantages of these three methods in relation to the quality control of soldered superconducting busbar cables enclosed in copper shells is used for benchmarking. The results of inspections with the U-shaped eddy current transducer carried out on several sample joints presenting different types of soldering defects show the potential of this type of nondestructive (ND) quality control technique.

  15. Active power filter for medium voltage networks with predictive current control

    Energy Technology Data Exchange (ETDEWEB)

    Verne, Santiago A.; Valla, Maria I. [Laboratorio de Electronica Industrial, Control e Instrumentacion (LEICI), Facultad de Ingenieria, Universidad Nacional de La Plata and CONICET, La Plata (Argentina)

    2010-12-15

    A transformer less Shunt Active Power Filter (SAPF) for medium voltage distribution networks based on Multilevel Diode Clamped Inverter is presented in this paper. Converter current control is based on a Model Predictive strategy, which gives very fast current response. Also, the algorithm includes voltage balancing capability which is essential for proper converter operation. The presented current control algorithm is naturally applicable to converters with an arbitrary number of levels with reduced computational effort by virtue of the incorporation of switching restrictions which are necessary for reliable converter operation. The performance of the proposed algorithm is evaluated by means of computer simulations. (author)

  16. Current situation of endoscopic biliary cannulation and salvage techniques for difficult cases: Current strategies in Japan.

    Science.gov (United States)

    Yasuda, Ichiro; Isayama, Hiroyuki; Bhatia, Vikram

    2016-04-01

    In the pancreatobiliary session at Endoscopic Forum Japan (EFJ) 2015, current trends of routine biliary cannulation techniques and salvage techniques for difficult biliary cannulation cases were discussed. Endoscopists from nine Japanese high-volume centers along with two overseas centers participated in the questionnaires and discussion. It was concluded that, currently, in Western countries, the wire-guided cannulation (WGC) technique is favored during initial cannulation attempts. However, the conventional technique using an endoscopic retrograde cholangiopancreatography catheter with contrast medium injection is still used as first choice at most Japanese high-volume centers. The WGC technique is used as the second choice at some institutions only. After failed biliary cannulation attempts, the initial salvage option preferred in most centers includes pancreatic guidewire placement, followed by precut techniques as the second salvage choice. Among several precut techniques, the free-hand needle knife sphincterotomy with cutting upwards from the pancreatic duct is most popular. Endoscopic ultrasonography-guided rendezvous technique is also carried out as a final salvage option at select institutions.

  17. Discrete-Time LPV Current Control of an Induction Motor

    DEFF Research Database (Denmark)

    Bendtsen, Jan Dimon; Trangbæk, Klaus

    2001-01-01

    In this paper we apply a new method for gain-scheduled output feedback control of nonlinear systems to current control of an induction motor. The method relies on recently developed controller synthesis results for linear parameter-varying (LPV) systems, where the controller synthesis is formulated...... as a set of linear matrix inequalities with full-block multipliers. A standard nonlinear model of the motor is then constructed and written on LPV form. We then show that, although originally developed in continuous time, the controller synthesis results can be applied to a discrete-time model as well...... without further complications. The synthesis method is applied to the model, yielding an LPV discrete-time controller. Finally, the efficiency of the control scheme is validated via simulations as well as experimentally on the actual induction motor, both in open-loop current control and when an outer...

  18. Control Plane Strategies for Elastic Optical Networks

    DEFF Research Database (Denmark)

    Turus, Ioan

    The goal of this Ph.d. project is to present and address selected challenges related to the increasing traffic demand and limited available capacity in core optical fiber infrastructure in parallel with tighter requirements of reducing energy consumption and operational costs. Elastic Optical...... consumption. EONs offer the opportunity of deploying energy efficiency strategies, which benefit from the flexible nature of elastic optoelectronic devices. This thesis proposes and investigates different approaches for reducing power consumption based on EONs in realistic dynamic traffic scenarios....

  19. A fault tolerant superheat control strategy for supermarket refrigeration systems

    DEFF Research Database (Denmark)

    Vinther, Kasper; Izadi-Zamanabadi, Roozbeh; Rasmussen, Henrik

    2013-01-01

    In this paper, a fault tolerant control (FTC) strategy is proposed for evaporator superheat control in supermarket refrigeration systems. Conventional control uses a pressure and temperature sensor for this purpose, however, the pressure sensor can fail to function. A contingency control strategy......, based on a maximum slope-seeking control method and only a single temperature sensor, is developed to drive the evaporator outlet temperature to a level that gives a suitable superheat of the refrigerant. The FTC strategy requires no a priori system knowledge or additional hardware and functions...... in a plug & play fashion. The strategy is outlined by means of procedural steps as well as a flow chart that also illustrates the process of automatic tuning of the maximum slope-seeking controller. Test results are furthermore presented for a display case in a full scale CO2 supermarket refrigeration...

  20. Short Horizon Control Strategies for an Alternating Activated Sludge Process

    DEFF Research Database (Denmark)

    Isaacs, Steven Howard

    1996-01-01

    determined. The effects of the strategies on short term nitrogen dynamics are explained in terms of the potential and capacity of denitrification. The relative effectiveness of the strategies are compared and where the strategies would be located in a hierarchical control structure is discussed. Copyright (C......Three control strategies allowing improved operational flexibility of an alternating type activated sludge process are presented in a unified model based framework. The control handles employed are the addition rate of an external carbon source to denitrification, the cycle length......, and the dissolved oxygen level during aerobic periods. All three strategies attempt to satisfy a common control criterion representing optimal performance over the time length of one process cycle (typically I to 3 hours) and are based on models developed from simple mass balances or which have been experimentally...

  1. Evaluation of Current Controllers for Distributed Power Generation Systems

    DEFF Research Database (Denmark)

    Timbus, Adrian; Liserre, Marco; Teodorescu, Remus

    2009-01-01

    This paper discusses the evaluation of different current controllers employed for grid-connected distributed power generation systems having variable input power, such as wind turbines and photovoltaic systems. The focus is mainly set on linear controllers such as proportional....... First, in steady-state conditions, the contribution of controllers to the total harmonic distortion of the grid current is pursued. Further on, the behavior of controllers in the case of transient conditions like input power variations and grid voltage faults is also examined. Experimental results...

  2. Control Strategies of an Inverted Pendulum.

    Science.gov (United States)

    1981-09-01

    AND PENDULUM --------- 12 2 FULL STATE VARIABLE FEEDBACK CONTROL SYSTEM - 31 3 CART QUARTER VIEW --------------------------- 34 4 CART TOP VIEW...system by moving the closed-loop poles to proper locations in the left-half plane. A feedback control system is one which attempts to main- tain a...pendulum angle oscillates on either side of zero. 30 x x x3 x 3 Figure 2. FULL STATE VARIABLE FEEDBACK CONTROL SYSTEM 31- IV. CONSTRUCTION OF INVERTED

  3. Backstepping Strategy for Induction Motor Control

    DEFF Research Database (Denmark)

    Rasmussen, Henrik; Vadstrup, P.; Børsting, H.

    2000-01-01

    Using backstepping, which is a recursive nonlinear design method, a novel approach to control of induction motors is developed. The resulting scheme leads to a nonlinear controller for the torque and the amplitude of the field. A combination of nonlinear damping and observer backstepping with a s...... with a simple flux observer is used in the design. Assuming known motor parameters the design achieves stability with guaranteed region of attraction. It is also shown how a conventional field oriented controller may be obtained by omitting parts of the nonlinear controller....

  4. Backstepping Strategy for Induction Motor Control

    DEFF Research Database (Denmark)

    Rasmussen, Henrik; Vadstrup, P.; Børsting, H.

    2000-01-01

    Using backstepping, which is a recursive nonlinear design method, a novel approach to control of induction motors is developed. The resulting scheme leads to a nonlinear controller for the torque and the amplitude of the field. A combination of nonlinear damping and observer backstepping with a s......Using backstepping, which is a recursive nonlinear design method, a novel approach to control of induction motors is developed. The resulting scheme leads to a nonlinear controller for the torque and the amplitude of the field. A combination of nonlinear damping and observer backstepping...

  5. Backstepping Strategy for Induction Motor Control

    DEFF Research Database (Denmark)

    Rasmussen, Henrik; Vadstrup, P.; Børsting, H.

    2000-01-01

    Using backstepping, which is a recursive nonlinear design method, a novel approach to control of induction motors is developed. The resulting scheme leads to a nonlinear controller for the torque and the amplitude of the field. A combination of nonlinear damping and observer backstepping...... with a simple flux observer is used in the design. Assuming known motor parameters the design achieves stability with guaranteed region of attraction. It is also shown how a conventional field oriented controller may be obtained by omitting parts of the nonlinear controller....

  6. Nitrate control strategies in an activated sludge wastewater treatment process

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Wenhao; Tao, Erpan; Chen, Xiaoquan; Liu, Dawei [South China University of Technology, Guangzhou (China); Liu, Hongbin [Kyung Hee University, Yongin (Korea, Republic of)

    2014-03-15

    We studied nitrate control strategies in an activated sludge wastewater treatment process (WWTP) based on the activated sludge model. Two control strategies, back propagation for proportional-integral-derivative (BP-PID) and adaptive-network based fuzzy inference systems (ANFIS), are applied in the WWTP. The simulation results show that the simple local constant setpoint control has poor control effects on the nitrate concentration control. However, the ANFIS (4*1) controller, which considers not only the local constant setpoint control of the nitrate concentration, but also three important indices in the effluent--ammonia concentration, total suspended sludge concentration and total nitrogen concentration--demonstrates good control performance. The results also prove that ANFIS (4*1) controller has better control performance than that of the controllers PI, BP-PID and ANFIS (2*1), and that the ANFIS (4*1) controller is effective in improving the effluent quality and maintaining the stability of the effluent quality.

  7. Improving Push Belt CVT Efficiency by Control Strategies Based on New Variator Wear Insight

    NARCIS (Netherlands)

    van der Laan, Maaike; van Drogen, Mark; Brandsma, Arjen

    2004-01-01

    Developments in clamping force control for the push belt Continuously Variable Transmission (CVT) aim at increased efficiency in combination with improved robustness. Current control strategies attempt to prevent macro slip between elements and pulleys at all times for maximum robustness. In order

  8. Linguistic Gender Sensitivity Strategies in Current South African Intermediate Phase English Workbooks: Feminisation or Degenderisation?

    Science.gov (United States)

    Sibanda, Jabulani; Sibanda, Lucy

    2016-01-01

    This study extends research on manifestations of gender insensitivity in learners' reading materials by shifting attention to the linguistic strategies that authors of current texts employ for the realisation of gender sensitivity. We analysed the content of 12 current (2014) English workbooks (Grade 4-6) used in South African government and…

  9. Linguistic Gender Sensitivity Strategies in Current South African Intermediate Phase English Workbooks: Feminisation or Degenderisation?

    Science.gov (United States)

    Sibanda, Jabulani; Sibanda, Lucy

    2016-01-01

    This study extends research on manifestations of gender insensitivity in learners' reading materials by shifting attention to the linguistic strategies that authors of current texts employ for the realisation of gender sensitivity. We analysed the content of 12 current (2014) English workbooks (Grade 4-6) used in South African government and…

  10. Backstepping Strategy for Induction Motor Control

    DEFF Research Database (Denmark)

    Rasmussen, Henrik; Vadstrup, P.; Børsting, H.

    2000-01-01

    Using backstepping, which is a recursive nonlinear design method, a novel approach to control of induction motors is developed. The resulting scheme leads to a nonlinear controller for the torque and the amplitude of the field. A combination of nonlinear damping and observer backstepping with a s...

  11. Strategy optimization for controlled Markov process with descriptive complexity constraint

    Institute of Scientific and Technical Information of China (English)

    JIA QingShan; ZHAO QianChuan

    2009-01-01

    Due to various advantages in storage and Implementation,simple strategies are usually preferred than complex strategies when the performances are close.Strategy optimization for controlled Markov process with descriptive complexity constraint provides a general framework for many such problems.In this paper,we first show by examples that the descriptive complexity and the performance of a strategy could be Independent,and use the F-matrix in the No-Free-Lunch Theorem to show the risk that approximating complex strategies may lead to simple strategies that are unboundedly worse in cardinal performance than the original complex strategies.We then develop a method that handles the descriptive complexity constraint directly,which describes simple strategies exactly and only approximates complex strategies during the optimization.The ordinal performance difference between the resulting strategies of this selective approximation method and the global optimum is quantified.Numerical examples on an engine maintenance problem show how this method Improves the solution quality.We hope this work sheds some insights to solving general strategy optimization for controlled Markov procase with descriptive complexity constraint.

  12. Health benefit modelling and optimization of vehicular pollution control strategies

    Science.gov (United States)

    Sonawane, Nayan V.; Patil, Rashmi S.; Sethi, Virendra

    2012-12-01

    This study asserts that the evaluation of pollution reduction strategies should be approached on the basis of health benefits. The framework presented could be used for decision making on the basis of cost effectiveness when the strategies are applied concurrently. Several vehicular pollution control strategies have been proposed in literature for effective management of urban air pollution. The effectiveness of these strategies has been mostly studied as a one at a time approach on the basis of change in pollution concentration. The adequacy and practicality of such an approach is studied in the present work. Also, the assessment of respective benefits of these strategies has been carried out when they are implemented simultaneously. An integrated model has been developed which can be used as a tool for optimal prioritization of various pollution management strategies. The model estimates health benefits associated with specific control strategies. ISC-AERMOD View has been used to provide the cause-effect relation between control options and change in ambient air quality. BenMAP, developed by U.S. EPA, has been applied for estimation of health and economic benefits associated with various management strategies. Valuation of health benefits has been done for impact indicators of premature mortality, hospital admissions and respiratory syndrome. An optimization model has been developed to maximize overall social benefits with determination of optimized percentage implementations for multiple strategies. The model has been applied for sub-urban region of Mumbai city for vehicular sector. Several control scenarios have been considered like revised emission standards, electric, CNG, LPG and hybrid vehicles. Reduction in concentration and resultant health benefits for the pollutants CO, NOx and particulate matter are estimated for different control scenarios. Finally, an optimization model has been applied to determine optimized percentage implementation of specific

  13. A GPS-Based Control Framework for Accurate Current Sharing and Power Quality Improvement in Microgrids

    DEFF Research Database (Denmark)

    Golsorkhi, Mohammad; Savaghebi, Mehdi; Lu, Dylan;

    2016-01-01

    consensus protocol to ensure proportional sharing of average power. The voltage conditioning scheme produces compensation signals at fundamental and dominant harmonics to improve the voltage quality at a sensitive load bus. Experimental results are presented to validate the efficacy of the proposed method.......This paper proposes a novel hierarchical control strategy for improvement of load sharing and power quality in ac microgrids. This control framework is composed of a droop based controller at the primary level, and a combination of distributed power sharing and voltage conditioning schemes...... dynamic response. The droop coefficient, which acts as a virtual resistance is adaptively changed as a function of the peak current. This strategy not only simplifies the control design but also improves the current sharing accuracy at high loading conditions. The distributed power sharing scheme uses...

  14. Control of microbial fuel cell voltage using a gain scheduling control strategy

    Science.gov (United States)

    Boghani, Hitesh C.; Michie, Iain; Dinsdale, Richard M.; Guwy, Alan J.; Premier, Giuliano C.

    2016-08-01

    Recent microbial fuel cell (MFC) research frequently addresses matters associated with scale and deployability. Modularisation is often needed to reduce ohmic losses with increasing volume. Series/parallel is then often an obvious strategy to enhance power quality during operation, to make best use of generated electricity. Hence, voltage reversal resulting from power and voltage mismatch between cells become virtually unavoidable. Control MFC voltages could be used to stabilise MFC stacks. Here, nonlinear MFCs are controlled using simple gain scheduled Proportional + Integral actions. Parsimonious control may be necessary for implementation in MFC arrays, so minimising costs. Controller parameterisation used several linearised models over the dynamic operating range of the MFCs. Controller gains were then scheduled according to the operating conditions. A digital potentiometer was used to actuate the control, varying the current sourced from the MFC. The results show that the controller was able to control MFC voltages, rejecting the disturbances. It was shown that the controller was transferable between MFCs with different power performances. This study demonstrates that the control of MFCs can be achieved with relatively simple digital approaches, plausibly implementable using low cost microcontrollers, and likely to be useful in the effective deployment of MFCs in large scale arrays.

  15. Control strategies for friction dampers: numerical assessment and experimental investigations.

    Directory of Open Access Journals (Sweden)

    Coelho H.T.

    2014-01-01

    Full Text Available The use of friction dampers has been proposed in a wide variety of mechanical systems for which it is not possible to apply viscoelastic materials, fluid based dampers or others viscous dampers. An important example is the application of friction dampers in aircraft engines to reduce the blades vibration amplitudes. In most cases, friction dampers have been studied in a passive way, however, a significant improvement can be achieved by controlling the normal force in the dampers. The aim of this paper is to study three control strategies for friction dampers based on the hysteresis cycle. The first control strategy maximizes the energy removal in each harmonic oscillation cycle, by calculating the optimum normal force based on the last displacement peak. The second control strategy combines the first one with the maximum energy removal strategy used in the smart spring devices. Finally, is presented the strategy which homogenously modulates the friction force. Numerical studies were performed with these three strategies defining the performance metrics. The best control strategy was applied experimentally. The experimental test rig was fully identified and its parameters were used for the numerical simulations. The obtained results show the good performance for the friction damper and the selected strategy.

  16. Efficient community-based control strategies in adaptive networks

    CERN Document Server

    Yang, Hui; Zhang, Hai-Feng

    2012-01-01

    Most researches on adaptive networks mainly concentrate on the properties of steady state, but neglect transient dynamics. In this study, we pay attention to the emergence of community structures in transient process and the effects of community-based control strategies on epidemic spreading. First, by normalizing modularity $Q$, we investigate the evolution of community structures during the transient process, and find that very strong community structures are induced by rewiring mechanism in the early stage of epidemic spreading, which remarkably delays the outbreaks of epidemic. Then we study the effects of control strategies started from different stages on the prevalence. Both immunization and quarantine strategies indicate that it is not "the earlier, the better" for the implementing of control measures. And the optimal control effect is obtained if control measures can be efficiently implemented in the period of strong community structure. For immunization strategy, immunizing the S nodes on SI links a...

  17. A STRATEGY IN WASTE MANAGEMENT AND CONTROL

    African Journals Online (AJOL)

    This paper examines the current trend in recycling as a ..... which was claimed to reduce wear problems in existing machines and which canuse up to 7% of the .... sorting the waste from homes, factories and establishment or at collectionpoints ...

  18. Energy storage system control strategies for power distribution systems

    Directory of Open Access Journals (Sweden)

    Areewan Kajorndech

    2015-03-01

    Full Text Available Energy storage systems have been widely employed to attain several benefits, such as reliability improvement, stabilization of power systems connected with renewable energy resources, economic benefits and etc. To achieve the above objectives, the appropriate and effective control strategies for energy storage systems are needed to be developed. This research proposes energy storage system control strategies for power distribution systems equipped with a limited size of energy storage system in order to improve reliability and save energy costs by determining an optimal charging schedule of the energy storage system. Simulation results demonstrate the benefits of energy storage system applications under the different control strategies.

  19. Porcine Rotaviruses: Epidemiology, Immune Responses and Control Strategies

    Science.gov (United States)

    Vlasova, Anastasia N.; Amimo, Joshua O.; Saif, Linda J.

    2017-01-01

    Rotaviruses (RVs) are a major cause of acute viral gastroenteritis in young animals and children worldwide. Immunocompetent adults of different species become resistant to clinical disease due to post-infection immunity, immune system maturation and gut physiological changes. Of the 9 RV genogroups (A–I), RV A, B, and C (RVA, RVB, and RVC, respectively) are associated with diarrhea in piglets. Although discovered decades ago, porcine genogroup E RVs (RVE) are uncommon and their pathogenesis is not studied well. The presence of porcine RV H (RVH), a newly defined distinct genogroup, was recently confirmed in diarrheic pigs in Japan, Brazil, and the US. The complex epidemiology, pathogenicity and high genetic diversity of porcine RVAs are widely recognized and well-studied. More recent data show a significant genetic diversity based on the VP7 gene analysis of RVB and C strains in pigs. In this review, we will summarize previous and recent research to provide insights on historic and current prevalence and genetic diversity of porcine RVs in different geographic regions and production systems. We will also provide a brief overview of immune responses to porcine RVs, available control strategies and zoonotic potential of different RV genotypes. An improved understanding of the above parameters may lead to the development of more optimal strategies to manage RV diarrheal disease in swine and humans. PMID:28335454

  20. A Versatile Control Scheme For Dynamic Voltage Restorer To Limit Downstream Fault Currents

    Directory of Open Access Journals (Sweden)

    A.Nagendra

    2014-12-01

    Full Text Available The Dynamic Voltage Restorer (DVR is a custom power device utilized to counteract voltage sags. It injects controlled three-phase ac voltages in series with the supply voltage, subsequent to voltage sag, to enhance voltage quality by adjusting the voltage magnitude, wave shape, and phase angle. The DVR is conventionally bypassed during a downstream fault to prevent potential adverse impacts on the fault and to protect the DVR components against the fault current. This paper proposes an augmented control strategy for the DVR that provides:1 voltage-sag compensation under balanced and unbalanced conditions and 2 a fault current interruption (FCI function. This paper introduces and evaluates an auxiliary control strategy for downstream fault current interruption in a radial distribution line by means of a dynamic voltage restorer (DVR. The proposed controller supplements the voltage-sag compensation control of the DVR. It does not require phaselocked loop and independently controls the magnitude and phase angle of the injected voltage for each phase. Fast least error squares digital filters are used to estimate the magnitude and phase of the measured voltages and effectively reduce the impacts of noise, harmonics, and disturbances on the estimated phasor parameters, and this enables effective fault current interrupting even under arcing fault conditions. The performance of the DVR for fault current interruption is analyzed by using MATLAB/SIMULINK software.

  1. An optimal control strategy for standalone PV system with Battery-Supercapacitor Hybrid Energy Storage System

    Science.gov (United States)

    Chong, Lee Wai; Wong, Yee Wan; Rajkumar, Rajprasad Kumar; Isa, Dino

    2016-11-01

    This paper proposes an optimal control strategy for a standalone PV system with Battery-Supercapacitor Hybrid Energy Storage System to prolong battery lifespan by reducing the dynamic stress and peak current demand of the battery. Unlike the conventional methods which only use either filtration based controller (FBC) or fuzzy logic controller (FLC), the proposed control strategy comprises of a low-pass filter (LPF) and FLC. Firstly, LPF removes the high dynamic components from the battery demand. FLC minimizes the battery peak current demand while constantly considering the state-of-charge of the supercapacitor. Particle swarm optimization (PSO) algorithm optimizes the membership functions of the FLC to achieve optimal battery peak current reduction. The proposed system is compared to the conventional system with battery-only storage and the systems with conventional control strategies (Rule Based Controller and FBC). The proposed system reduces the battery peak current, battery peak power, maximum absolute value of the rate of change of power and average absolute value of the rate of change of power by 16.05%, 15.19%, 77.01%, and 95.59%, respectively as compared to the conventional system with battery-only storage. Moreover, he proposed system increases the level of supercapacitor utilization up to 687.122% in comparison to the conventional control strategies.

  2. Preschool Power Play: Resource Control Strategies Associated with Health

    Directory of Open Access Journals (Sweden)

    Amber R. Massey

    2014-01-01

    Full Text Available Background. This exploratory study uses a multimethod approach to examine the relationship between social strategy usage and overall health in preschool children. Methods. Children's temperament, social strategies, and health assessments were obtained via reported behavior from parents and teachers. In addition, children's use of prosocial and coercive strategies was observed and recorded via one-way windows in the preschool facility. Results. Results revealed that the temperament characteristic of effortful control was related to the observed use of coercive strategies and that coercive strategies were not observed by teachers, who viewed these children as primarily prosocial. The reported use of both coercive and prosocial strategies was also related to decrease in illness. Conclusion. These findings in relation to previous work suggest that using both prosocial and coercive strategies can elevate status as well as maintain health even in young children.

  3. The Modeling Strategies for Open Software Architecture of Robot Controller

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Although the modeling technologies for open robot controllers have been discussed widely, not much literature is devoted to the actual general modeling principles and strategies. The reason is that many researches focus on specific application fields. This paper accommodates for this lacuna and provides some general modeling principles and strategies. At last, the actual new modeling method -Hierarchical Object-Oriented Petri net (HOONet) which has been proved to be an effective modeling methodology, is used to illustrate the modeling strategies.

  4. Design and Implementation of a Control Strategy for Microgrid Containing Renewable Energy Generations and Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Mingchao Xia

    2013-01-01

    Full Text Available Large amount of such renewable energy generations as wind/photovoltaic generations directly connected to grid acting as distributed generations will cause control, protection, security, and safety problems. Microgrid, which has advantages in usage and control of distributed generations, is a promising approach to coordinate the conflict between distributed generations and the grid. Regarded as mobile power storages, batteries of electric vehicles can depress the fluctuation of power through the point of common coupling of microgrid. This paper presents a control strategy for microgrid containing renewable energy generations and electric vehicles. The control strategy uses current control for renewable energy generations under parallel-to-grid mode, and uses master-slave control under islanding mode. Simulations and laboratory experiments prove that the control strategy works well for microgrid containing renewable energy generations and electric vehicles and provides maximum power output of renewable energy and a stable and sustainable running under islanding mode.

  5. MODEL STUDY OF THE DOUBLE FED MACHINE WITH CURRENT CONTROL

    Directory of Open Access Journals (Sweden)

    A. S. Lyapin

    2016-07-01

    Full Text Available The paper deals with modeling results of the double fed induction machine with current control in the rotor circuit. We show the most promising applications of electric drives on the basis of the double fed induction machine and their advantages. We present and consider functional scheme of the electric drive on the basis of the double fed induction machine with current control. Equations are obtained for creation of such machine mathematical model. Expressions for vector projections of rotor current are given. According to the obtained results, the change of the vector projections of rotor current ensures operation of the double fed induction machine with the specified values of active and reactive stator power throughout the variation range of sliding motion. We consider static characteristics of double fed machine with current control. Energy processes proceeding in the machine are analyzed. We confirm the operationpossibility of double fed induction machine with current controlin the rotor circuit with given values of active and reactive stator power. The presented results can be used for creation of mathematical models and static characteristics of double fed machines with current control of various capacities.

  6. A systematic review of current and emergent manipulator control approaches

    Science.gov (United States)

    Ajwad, Syed Ali; Iqbal, Jamshed; Ullah, Muhammad Imran; Mehmood, Adeel

    2015-06-01

    Pressing demands of productivity and accuracy in today's robotic applications have highlighted an urge to replace classical control strategies with their modern control counterparts. This recent trend is further justified by the fact that the robotic manipulators have complex nonlinear dynamic structure with uncertain parameters. Highlighting the authors' research achievements in the domain of manipulator design and control, this paper presents a systematic and comprehensive review of the state-of-the-art control techniques that find enormous potential in controlling manipulators to execute cuttingedge applications. In particular, three kinds of strategies, i.e., intelligent proportional-integral-derivative (PID) scheme, robust control and adaptation based approaches, are reviewed. Future trend in the subject area is commented. Open-source simulators to facilitate controller design are also tabulated. With a comprehensive list of references, it is anticipated that the review will act as a firsthand reference for researchers, engineers and industrialinterns to realize the control laws for multi-degree of freedom (DOF) manipulators.

  7. Controlling ultrafast currents by the nonlinear photogalvanic effect

    Science.gov (United States)

    Wachter, Georg; Sato, Shunsuke A.; Floss, Isabella; Lemell, Christoph; Tong, Xiao-Min; Yabana, Kazuhiro; Burgdörfer, Joachim

    2015-12-01

    We investigate the effect of broken inversion symmetry on the generation and control of ultrafast currents in a transparent dielectric (SiO2) by strong femtosecond optical laser pulses. Ab initio simulations based on time-dependent density functional theory predict ultrafast direct currents that can be viewed as a nonlinear photogalvanic effect. Most surprisingly, the direction of the current undergoes a sudden reversal above a critical threshold value of laser intensity of about {I}{{c}}˜ 3× {10}13 W cm-2. We trace this switching to the transition from nonlinear polarisation currents to the tunnelling excitation regime. The latter is found to be sensitive to the relative orientation between laser polarisation and chemical bonds. We demonstrate control of the ultrafast currents by the time delay between two laser pulses. While two temporally separated laser pulses lead to currents along one direction their temporal overlap can reverse the current. We find the ultrafast current control by the nonlinear photogalvanic effect to be remarkably robust and insensitive to the laser-pulse shape and the carrier-envelope phase.

  8. Element Tracking Strategies for Hot Strip Laminar Cooling Control

    Institute of Scientific and Technical Information of China (English)

    HAN Bin; ZHANG Zhong-ping; LIU Xiang-hua; WANG Guo-dong

    2005-01-01

    Feedforward control is the core to control function in the cooling process of hot strip. One of the most important tasks in feedforward control is to determine the arrival time of the strip at various locations on the runout table for effective control. Based on the principles of element tracking and tracking strategies for variable rolling speed and constant rolling speed, a simple diagonal tracking method for an existing hot strip mill was proposed and tested. The test results show that the proposed strategies are effective for improving tracking control.

  9. Optimal Control Strategies in Delayed Sharing Information Structures

    CERN Document Server

    Nayyar, Ashutosh; Teneketzis, Demosthenis

    2010-01-01

    The $n$-step delayed sharing information structure is investigated. This information structure comprises of $K$ controllers that share their information with a delay of $n$ time steps. This information structure is a link between the classical information structure, where information is shared perfectly between the controllers, and a non-classical information structure, where there is no "lateral" sharing of information among the controllers. Structural results for optimal control strategies for systems with such information structures are presented. A sequential methodology for finding the optimal strategies is also derived. The solution approach provides an insight for identifying structural results and sequential decomposition for general decentralized stochastic control problems.

  10. Power Management Based Current Control Technique for Photovoltaic-Battery Assisted Wind-Hydro Hybrid System

    Science.gov (United States)

    Ram Prabhakar, J.; Ragavan, K.

    2013-07-01

    This article proposes new power management based current control strategy for integrated wind-solar-hydro system equipped with battery storage mechanism. In this control technique, an indirect estimation of load current is done, through energy balance model, DC-link voltage control and droop control. This system features simpler energy management strategy and necessitates few power electronic converters, thereby minimizing the cost of the system. The generation-demand (G-D) management diagram is formulated based on the stochastic weather conditions and demand, which would likely moderate the gap between both. The features of management strategy deploying energy balance model include (1) regulating DC-link voltage within specified tolerances, (2) isolated operation without relying on external electric power transmission network, (3) indirect current control of hydro turbine driven induction generator and (4) seamless transition between grid-connected and off-grid operation modes. Furthermore, structuring of the hybrid system with appropriate selection of control variables enables power sharing among each energy conversion systems and battery storage mechanism. By addressing these intricacies, it is viable to regulate the frequency and voltage of the remote network at load end. The performance of the proposed composite scheme is demonstrated through time-domain simulation in MATLAB/Simulink environment.

  11. Designed patterns: flexible control of precipitation through electric currents.

    Science.gov (United States)

    Bena, I; Droz, M; Lagzi, I; Martens, K; Rácz, Z; Volford, A

    2008-08-15

    Understanding and controlling precipitation patterns formed in reaction-diffusion processes is of fundamental importance with high potential for technical applications. Here we present a theory showing that precipitation resulting from reactions among charged agents can be controlled by an appropriately designed, time-dependent electric current. Examples of current dynamics yielding periodic bands of prescribed wavelength, as well as more complicated structures are given. The pattern control is demonstrated experimentally using the reaction-diffusion process 2AgNO3 + K2Cr2O7-->under Ag2Cr2O7 + 2KNO3.

  12. A Tool for the Development of Robot Control Strategies

    Directory of Open Access Journals (Sweden)

    Luiz Carlos Figueiredo

    2007-12-01

    Full Text Available In this paper we report as the development of a tool in to develop and set control strategies as a fast and easy way. Additionally, a tricycle robot with two traction motors was built to test the strategies produced with the tool. Experimental tests have shown an advantage in the use of such tool.

  13. 40 CFR 52.2585 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.2585... strategy: Ozone. (a) Disapproval—On November 6, 1986, the Wisconsin Department of Natural Resources... necessary to offset growth in emissions. (h) Approval—On November 15, 1993, the Wisconsin Department of...

  14. 40 CFR 52.2235 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.2235... strategy: Ozone. (a) Determination—EPA is determining that, as of August 8, 1995, the Nashville ozone nonattainment area has attained the ozone standard and that the reasonable further progress and...

  15. 40 CFR 52.2088 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.2088... strategy: Ozone. (a) Revisions to the State Implementation Plan submitted by the Rhode Island Department of...) of the Clean Air Act, for the Providence serious ozone nonattainment area. (b) Approval—Revisions...

  16. 40 CFR 52.1129 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.1129... strategy: Ozone. (a) Revisions to the State Implementation Plan submitted by the Massachusetts Department...) and 182(c)(2)(B) of the Clean Air Act for the Springfield, Massachusetts serious ozone...

  17. 40 CFR 52.1534 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.1534... strategy: Ozone. (a) Revisions to the State Implementation Plan submitted by the New Hampshire Department... revisions are for the purpose of satisfying the one-hour ozone attainment demonstration requirements...

  18. 40 CFR 52.1486 - Control strategy: Hydrocarbons and ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Hydrocarbons and ozone. 52.1486 Section 52.1486 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... strategy: Hydrocarbons and ozone. (a) The requirements of subpart G of this chapter are not met since...

  19. FACTS device control strategy using PMU

    Directory of Open Access Journals (Sweden)

    Mohd Tauseef Khan

    2016-09-01

    Full Text Available The laying and commissioning of new transmission line is very difficult due to socio-economic problems, like environmental clearances, right of way, etc. Therefore, there is an emphasis on better utilization of available transmission infrastructure. FACTS devices can provide reactive power compensation, transmission capability enhancement, and voltage and stability improvement. FACTS devices operate under the command of system operator who analyses its demand by the data acquired through traditional SCADA system, state estimation algorithms and PMUs. SCADA together with PMU give accurate information about the operational state of power system. This paper proposes a scheme to automate the FACTS devices in collaboration with PMUs in a more efficient way. Highly precised data from PMUs can be fed to intelligent controllers for effective analyzing and automating the FACTS device through control command. Thus, this combination can provide real time control of reactive power, together with enhancement of power handling capability and stability improvement.

  20. Discrete-Time LPV Current Control of an Induction Motor

    DEFF Research Database (Denmark)

    Bendtsen, Jan Dimon; Trangbæk, Klaus

    2003-01-01

    In this paper we apply a new method for gain-scheduled output feedback control of nonlinear systems to current control of an induction motor. The method relies on recently developed controller synthesis results for linear parameter-varying (LPV) systems, where the controller synthesis is formulated...... as a set of linear matrix inequalities with full-block multipliers. A standard nonlinear model of the motor is constructed and written on LPV form. We then show that, although originally developed in continuous time, the controller synthesis results can be applied to a discrete-time model as well without...

  1. The Myriad Strategies for Seeking Control in the Dying Process

    Science.gov (United States)

    Schroepfer, Tracy A.; Noh, Hyunjin; Kavanaugh, Melinda

    2009-01-01

    Purpose: This study explored the role control plays in the dying process of terminally ill elders by investigating the aspects of the dying process over which they seek to exercise control, the strategies they use, and whether they desire to exercise more control. Design and Methods: In-depth face-to-face interviews were conducted with 84…

  2. Strategies for glucose control in people with type 1 diabetes

    DEFF Research Database (Denmark)

    Boiroux, Dimitri; Finan, Daniel Aaron; Jørgensen, John Bagterp

    2011-01-01

    In this paper we apply a robust feedforward-feedback control strategy to people with type 1 diabetes. The feedforward controller consists of a bolus calculator which compensates the disturbance coming from meals. The feedback controller is based on a linearized description of the model describing...

  3. A Novel Hybrid Safety-control Strategy for a Manipulator

    Directory of Open Access Journals (Sweden)

    Jing Xia

    2014-04-01

    Full Text Available As robots tend to work cooperatively with humans in shared workplaces, safety as regards robot- human interactions has caused a great deal of concern in the robot community, and control strategies have become a hot topic in robotics research. In order to guarantee the robot’s safety and continuous motions, this paper proposes a novel safety-control strategy, which is strictly conservative and which consists of a pre-contact and post-contact safety strategy. We adopt an optimal motion trajectory-planning method, by use of which the jerk, acceleration and velocity of the robot’s motion can be limited and a time-optimal motion can be obtained as a post-contact safety strategy for a position-controlled manipulator. The optimal motion trajectory planning not only reduces the impact forces during the collision period, but also maintains the efficiency of the manipulator and preserves continuous motions. Next, we describe a novel collision detection method as a pre-contact safety strategy to avoid collisions. The method proposed here can compute security warning region to handle the effect of robot motion on collision detection and detect collisions between non-convex polygon soups. Finally, the control strategy is implemented for a 7-DOF humanoid manipulator and the experimental results demonstrate the validity of this novel hybrid safety-control strategy.

  4. An integrated pest management program as a pests control strategy ...

    African Journals Online (AJOL)

    Phukubje, Justice

    identify high risk areas within collection and the surrounding ... that integrated pest management strategies should be augmented ... Library Associations and Institutions (IFLA) publication .... of pests control, financial challenges, lack of policies ...

  5. Energy control strategy for parallel hydrostatic transmission hybrid vehicles

    Institute of Scientific and Technical Information of China (English)

    SUN Hui; JIANG Ji-hai; WANG Xin

    2009-01-01

    Aimed at the relatively lower energy density and complicated coordinating operation between two power sources, a special energy control strategy is required to maximize the fuel saving potential. Then a new type of configuration for hydrostatic transmission hybrid vehicles (PHHV) and the selection criterion for impor-tant components are proposed. Based on the optimization of planet gear transmission ratio and the analysis of op-timal energy distribution for the proposed PHHV on a representative urban driving cycle, a fuzzy torque control strategy and a braking energy regeneration strategy are designed and developed to realize the real-time control of energy for the proposed PHHV. Simulation results demonstrate that the energy control strategy effectively im-proves the fuel economy of PHHV.

  6. 40 CFR 52.1877 - Control strategy: Photochemical oxidants (hydrocarbons).

    Science.gov (United States)

    2010-07-01

    ... oxidants (hydrocarbons). 52.1877 Section 52.1877 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY....1877 Control strategy: Photochemical oxidants (hydrocarbons). (a) The requirements of Subpart G of this... national standard for photochemical oxidants (hydrocarbons) in the Metropolitan Cincinnati...

  7. A novel control strategy for load converter of DC isolated distribution system under unbalanced loading conditions

    Institute of Scientific and Technical Information of China (English)

    R. NOROOZIAN; M. ABEDI; G.B. GHAREHPETIAN; S. H. HOSSEINI

    2009-01-01

    A novel control strategy for the load converter supplying the unbalanced AC load in a DC isolated distribution system is presented. The control algorithm results in balanced and sinusoidal load voltages under unbalanced AC loading. The unbalanced load is characterized in the d-q-0 rotating coordinate based on symmetrical sequence components. Also, the mathematical model of the load converter in both a-b-c and d-q-0 coordinates is derived by using the average large signal model. Then, two control strategies for the load converter are presented. The first one uses the conventional d-q-0 controller to ensure the voltage and current regulation. The second one is a newly proposed control strategy based on the decomposition of the voltage and current into instantaneous positive, negative, and zero sequences. These three sequences are controlled independently in their own reference frames as DC signals. The performance of the load converter using these two control strategies is compared. Simulation results show the validity and capability of the newly proposed control strategy.

  8. Plant-based strategies for mosquito control

    Science.gov (United States)

    Mosquitoes transmit some of the most devastating emerging infectious diseases of humans, domestic animals, and wildlife. Although vector control by use of chemical insecticides has played an important role in prevention and management of these diseases, their sustained use remains questionable due t...

  9. Control of an extending nonlinear elastic cable with an active vibration control strategy

    Science.gov (United States)

    Dai, L.; Sun, L.; Chen, C.

    2014-10-01

    An active control strategy based on the fuzzy sliding mode control (FSMC) is developed in this research for controlling the large-amplitude vibrations of an extending nonlinear elastic cable. The geometric nonlinearity of the cable and the fixed-fixed boundary of the cable are considered. For effectively and accurately control the motion of the cable with the active control strategy developed, the governing equation of the elastic cable is established and transformed into a multi-dimensional dynamic system with the 3rd order Galerkin method. The active control strategy is developed on the basis of the dynamic system, and the control strategy is applicable to multi-dimensional dynamic systems. In the numerical simulation, large-amplitude vibrations of the cable are effectively controlled with the control strategy. The results of the research demonstrate significances for controlling the cable vibrations of an elevator in practice.

  10. Energy storage system control strategies for power distribution systems

    OpenAIRE

    Areewan Kajorndech; Dulpichet Rerkpreedapong

    2015-01-01

    Energy storage systems have been widely employed to attain several benefits, such as reliability improvement, stabilization of power systems connected with renewable energy resources, economic benefits and etc. To achieve the above objectives, the appropriate and effective control strategies for energy storage systems are needed to be developed. This research proposes energy storage system control strategies for power distribution systems equipped with a limited size of energy storage system ...

  11. Integrated Control Strategies Supporting Autonomous Functionalities in Mobile Robots

    Science.gov (United States)

    2005-01-01

    Integrated Control Strategies Supporting Autonomous Functionalities in Mobile Robots B. Sightsa, H.R. Everetta, E. Biagtan Pacisa, G. Koguta M...TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Integrated Control Strategies Supporting Autonomous Functionalities in Mobile Robots 5a...calculation methods using encoder counts, wheel radius, and the robot’s wheelbase, as described in Sensors For Mobile Robots [5]. On top of this

  12. Sliding Mode Robustness Control Strategy for Shearer Height Adjusting System

    Directory of Open Access Journals (Sweden)

    Xiuping Su

    2013-09-01

    Full Text Available This paper firstly established mathematical model of height adjusting hydro cylinder of the shearer, as well as the state space equation of the shearer height adjusting system. Secondly we designed a shearer automatic height adjusting controller adopting the sliding mode robustness control strategy. The height adjusting controller includes the sliding mode surface switching function based on Ackermann formula, as well as sliding mode control function with the improved butterworth filter. Then simulation of the height adjustment controller shows that the sliding mode robustness control solves buffeting of typical controller, and achieves automatic control for the rolling drum of the shearer.

  13. Fissura por crack: comportamentos e estratégias de controle de usuários e ex-usuários Ansia de consumo por crack: conductas y estrategias de control de usuarios y ex-usuarios Crack cocaine craving: behaviors and coping strategies among current and former users

    Directory of Open Access Journals (Sweden)

    Tharcila V Chaves

    2011-12-01

    ser herramienta importante para perfeccionar el tratamiento.OBJECTIVE: To understand crack cocaine craving among users and describe craving behaviors and coping strategies. METHODOLOGICAL PROCEDURES: Qualitative study with a non-random criterion sample consisting of 40 current and former crack cocaine users conducted in São Paulo, southeast Brazil, in 2007 and 2008. Respondents were selected using snowball sampling technique. In-depth semi-structured interviews were conducted until theoretical saturation was attained. All interviews were transcribed and content analysis was performed to construct inferences and hypotheses based on the narratives. ANALYSIS OF RESULTS: The respondents showed a similar gender distribution, were 18 to 50 years of age, and had different levels of education. Most were from low-income background. In addition to craving resulting from crack cocaine withdrawal and environmental and emotional cue effects, it was found that crack cocaine itself triggers craving. The latter appeared to be a strong trigger of binge episodes. Binge episodes made them lose their moral values, and act dangerously to get more drug. The most common ways reported to get crack cocaine or money to buy it were: prostitution, manipulation of other people, go into debt, sell personal belongings to buy drug and theft. The respondents reported strategies to overcome their cravings as well as pharmacological and behavioral approaches to prevent cravings such as eating, having sex, playing soccer, working, avoiding social situations of crack use and taking depressants. CONCLUSIONS: Crack cocaine binges are caused by a craving induced by the effects of crack cocaine itself. Users develop self-control strategies to cope with their cravings that may help improve their drug use and treatment effectiveness.

  14. Unified power flow controller: Modeling, stability analysis, control strategy and control system design

    Science.gov (United States)

    Sreenivasachar, Kannan

    2001-07-01

    Unified power flow controller (UPFC) has been the most versatile Flexible AC Transmission System (FACTS) device due to its ability to control real and reactive power flow on transmission lines while controlling the voltage of the bus to which it is connected. UPFC being a multi-variable power system controller it is necessary to analyze its effect on power system operation. To study the performance of the UPFC in damping power oscillations using PSCAD-EMTDC software, a de-coupled control system has been designed for the shunt inverter to control the UPFC bus voltage and the DC link capacitor voltage. The series inverter of a UPFC controls the real power flow in the transmission line. One problem associated with using a high gain PI controller (used to achieve fast control of transmission line real power flow) for the series inverter of a UPFC to control the real power flow in a transmission line is the presence of low damping. This problem is solved in this research by using a fuzzy controller. A method to model a fuzzy controller in PSCAD-EMTDC software has also been described. Further, in order to facilitate proper operation between the series and the shunt inverter control system, a new real power coordination controller has been developed and its performance was evaluated. The other problem concerning the operation of a UPFC is with respect to transmission line reactive power flow control. Step changes to transmission line reactive power references have significant impact on the UPFC bus voltage. To reduce the adverse effect of step changes in transmission line reactive power references on the UPFC bus voltage, a new reactive power coordination controller has been designed. Transient response studies have been conducted using PSCAD-EMTDC software to show the improvement in power oscillation damping with UPFC. These simulations include the real and reactive power coordination controllers. Finally, a new control strategy has been proposed for UPFC. In this

  15. Planning strategies for nosocomial infection control.

    Science.gov (United States)

    Lacanna, Giuseppe

    2014-01-01

    According to the American Centers for Disease Control and Prevention, 99,000 deaths per year in the United States are caused or impacted on by multiple hospital-acquired infections (HAIs), which are roughly estimated to be around 1.7 million cases. In Europe, there are 25,000 deaths per year from the same cause, 17.000 of which are linked to nosocomial infections. Patient safety is a core issue in today's health care settings. There is a growing consensus, supported by scientific investigation, that the role of the built environment is central towards minimizing and controlling the level of such infections. The contribution of architectural solutions and planning choices becomes crucial at this stage. This paper outlines the most common measures to adopt at the architectural and planning level, to combat HAI, focusing on the most critical areas of the hospital: wards, intensive care units and operating theatres.

  16. Mesh refinement strategy for optimal control problems

    OpenAIRE

    Paiva, Luis Tiago; Fontes, Fernando,

    2013-01-01

    International audience; Direct methods are becoming the most used technique to solve nonlinear optimal control problems. Regular time meshes having equidistant spacing are frequently used. However, in some cases these meshes cannot cope accurately with nonlinear behavior. One way to improve the solution is to select a new mesh with a greater number of nodes. Another way, involves adaptive mesh refinement. In this case, the mesh nodes have non equidistant spacing which allow a non uniform node...

  17. Modelling the transport system in China and evaluating the current strategies towards the sustainable transport development

    DEFF Research Database (Denmark)

    Liu, W.; Lund, H.; Mathiesen, B.V.

    2013-01-01

    in China. With this purpose in mind, a Chinese transport model has been created and three current transport strategies which are high speed railway (HSR), urban rail transit (URT) and electric vehicle (EV) were evaluated together with a reference transport system in 2020. As conservative results, 13......Transport is one of the most challenge sectors when addressing energy security and climate change due to its high reliance on oil products and lack of the alternative fuels. This paper explores the ability of three transport strategies to contribute to the development of a sustainable transport......% of the energy saving and 12% of the CO2 emission reduction can be attained by accomplishing three strategies compared with the reference transport system. However, the energy demand of transport in 2020 with the implementation of three strategies will be about 1.7 times as much as today. The three strategies...

  18. Evaluation of control strategies in forming processes

    Directory of Open Access Journals (Sweden)

    Calmano Stefan

    2015-01-01

    Full Text Available Products of forming processes are subject to quality fluctuations due to uncertainty in semi-finished part properties as well as process conditions and environment. An approach to cope with these uncertainties is the implementation of a closed-loop control taking into account the actual product properties measured by sensors or estimated by a mathematical process model. Both methods of uncertainty control trade off with a financial effort. In case of sensor integration the effort is the cost of the sensor including signal processing as well as the design and manufacturing effort for integration. In case of an estimation model the effort is mainly determined by the time and knowledge needed to derive the model, identify the parameters and implement the model into the PLC. The risk of mismatch between model and reality as well as the risk of wrong parameter identification can be assumed as additional uncertainty (model uncertainty. This paper evaluates controlled and additional uncertainty by taking into account process boundary conditions like the degree of fluctuations in semi-finished part properties. The proposed evaluation is demonstrated by the analysis of exemplary processes.

  19. Multiple sclerosis: current and emerging disease-modifying therapies and treatment strategies.

    Science.gov (United States)

    Wingerchuk, Dean M; Carter, Jonathan L

    2014-02-01

    Multiple sclerosis (MS) is a chronic inflammatory demyelinating central nervous system disease that typically strikes young adults, especially women. The pathobiology of MS includes inflammatory and neurodegenerative mechanisms that affect both white and gray matter. These mechanisms underlie the relapsing, and often eventually progressive, course of MS, which is heterogeneous; confident prediction of long-term individual prognosis is not yet possible. However, because revised MS diagnostic criteria that incorporate neuroimaging data facilitate early diagnosis, most patients are faced with making important long-term treatment decisions, most notably the use and selection of disease-modifying therapy (DMT). Currently, there are 10 approved MS DMTs with varying degrees of efficacy for reducing relapse risk and preserving neurological function, but their long-term benefits remain unclear. Moreover, available DMTs differ with respect to the route and frequency of administration, tolerability and likelihood of treatment adherence, common adverse effects, risk of major toxicity, and pregnancy-related risks. Thorough understanding of the benefit-risk profiles of these therapies is necessary to establish logical and safe treatment plans for individuals with MS. We review the available evidence supporting risk-benefit profiles for available and emerging DMTs. We also assess the place of individual DMTs within the context of several different MS management strategies, including those currently in use (sequential monotherapy, escalation therapy, and induction and maintenance therapy) and others that may soon become feasible (combination approaches and "personalized medicine"). We conducted this review using a comprehensive search of MEDLINE, PubMed, EMBASE, Cochrane Database of Systematic Reviews, and Cochrane Central Register of Controlled Trials, from January 1, 1990, to August 31, 2013. The following search terms were used: multiple sclerosis, randomized controlled trials

  20. Comparison of different control strategies on FMD in Denmark

    DEFF Research Database (Denmark)

    Boklund, Anette; Hisham Beshara Halasa, Tariq; Christiansen, Lasse Engbo

    2012-01-01

    of epidemics vary much with the type of index herd (starting points). Furthermore, not only economy, but also ethical and political issues will also play an important role in decision making. Therefore, it is important to keep in mind that this work will not give the answer as to which strategy to use during......The purpose of this study was to compare different control strategies that could be used in Denmark during an outbreak of FMD, based on epidemiological, ethical and economic parameters. Nearly a hundred different control strategies and more than 30 sensitivity analyses were run, changing between...... an epidemic, but can be used as a decision support tool. Sometimes, even though one strategy will be predicted to be cheaper, the second cheapest strategy might reduce the number of killed animals so much that it will become a better option....

  1. Control and Protection Cooperation Strategy for Voltage Instability

    DEFF Research Database (Denmark)

    Liu, Zhou; Chen, Zhe; Sun, Haishun;

    2012-01-01

    Most cascaded blackouts are caused by unexpected backup relay operations due to low voltage or overload state caused by post fault load restoration dynamics. If such state can be sensed and adjusted appropriately prior to those relay actions, system stability might be sustained. This paper proposed...... a control and protection cooperation strategy to prevent post fault voltage instability. The multi-agent technology is applied for the strategy implementation; the criteria based on wide area measured apparent impedances are defined to choose the control strategy, such as tap changer adjusting or load...

  2. Model Predictive Control with Integral Action for Current Density Profile Tracking in NSTX-U

    Science.gov (United States)

    Ilhan, Z. O.; Wehner, W. P.; Schuster, E.; Boyer, M. D.

    2016-10-01

    Active control of the toroidal current density profile may play a critical role in non-inductively sustained long-pulse, high-beta scenarios in a spherical torus (ST) configuration, which is among the missions of the NSTX-U facility. In this work, a previously developed physics-based control-oriented model is embedded in a feedback control scheme based on a model predictive control (MPC) strategy to track a desired current density profile evolution specified indirectly by a desired rotational transform profile. An integrator is embedded into the standard MPC formulation to reject various modeling uncertainties and external disturbances. Neutral beam powers, electron density, and total plasma current are used as actuators. The proposed MPC strategy incorporates various state and actuator constraints directly into the control design process by solving a constrained optimization problem in real-time to determine the optimal actuator requests. The effectiveness of the proposed controller in regulating the current density profile in NSTX-U is demonstrated in closed-loop nonlinear simulations. Supported by the US DOE under DE-AC02-09CH11466.

  3. MPPT control of Photovoltaic using SEPIC converter to reduce the input current ripples

    Directory of Open Access Journals (Sweden)

    M. R. Banaei

    2014-01-01

    Full Text Available This paper presents P&O control method for maximum power point tracking(MPPT of PV system under varying irradiation and temperature conditions. This algorithm will identify the suitable duty ratio in which the DC/DC SEPIC converter should be operated to maximize the power output. In this paper, the SEPIC converter has been compared with conventional boost converter about reducing the input current ripple. Also, both converters and their control strategies have been analyzed and simulated using Simulink/Matlab software. Simulation results show that the SEPIC converter reduces input current better than conventional boost converter.

  4. Novel strategies for control of fermentation processes

    DEFF Research Database (Denmark)

    Mears, Lisa; Stocks, Stuart; Sin, Gürkan

    Bioprocesses are inherently sensitive to fluctuations in processing conditions and must be tightly regulated to maintain cellular productivity. Industrial fermentations are often difficult to replicate across production sites or between facilities as the small operating differences in the equipment...... of a fermentation. Industrial fermentation processes are typically operated in fed batch mode, which also poses specific challenges for process monitoring and control. This is due to many reasons including non-linear behaviour, and a relatively poor understanding of the system dynamics. It is therefore challenging...

  5. The density matrix picture of laser coherent control current

    Institute of Scientific and Technical Information of China (English)

    SHOU Qian; ZHANG Haichao; LIU Luning; LIN Weizhu

    2004-01-01

    The physical substance of the coherent control current and the optical rectification have been analyzed based on density matrix perturbation theory. The analytical results demonstrate that they arise from the real and virtual manifestations of the same nonlinear process associated with diagonal and non-diagonal density matrix.And in terms of polarization, they respectively arise from the intraband and interband polarizations. Both the evolution of the coherent control current exited by ultrafast laser pulse and its dependence on frequency have been studied in time and frequency domains. In order to get an explicit knowledge of intraband polarization and the origination of the coherent control current, we have investigated the initial photo-carriers momentum distribution. The ultrafast decay of the polar momentum population in order of tens of femtosends is given to illustrate its instantaneous optical response.

  6. Design of a Novel Current Balanced Voltage Controlled Delay Element

    Directory of Open Access Journals (Sweden)

    Pooja Saxena

    2014-04-01

    Full Text Available This paper presents a design of fast voltage controlled delay element based on modified version of low noise Current Balanced Logic (CBL. This delay element provides identical rising and falling edge delays controlled by the single control voltage. The post layout tunable delay range is from 140 ps to 800 ps over control voltage range of 0 to 2.1 V. An analysis for the delay element is also presented, which is in agreement with the simulated delays. A Delay Lock Loop (DLL is designed using this delay element to verify its performance.

  7. Generalized space vector control for current source inverters and rectifiers

    Directory of Open Access Journals (Sweden)

    Roseline J. Anitha

    2016-06-01

    Full Text Available Current source inverters (CSI is one of the widely used converter topology in medium voltage drive applications due to its simplicity, motor friendly waveforms and reliable short circuit protection. The current source inverters are usually fed by controlled current source rectifiers (CSR with a large inductor to provide a constant supply current. A generalized control applicable for both CSI and CSR and their extension namely current source multilevel inverters (CSMLI are dealt in this paper. As space vector pulse width modulation (SVPWM features the advantages of flexible control, faster dynamic response, better DC utilization and easy digital implementation it is considered for this work. This paper generalizes SVPWM that could be applied for CSI, CSR and CSMLI. The intense computation involved in framing a generalized space vector control are discussed in detail. The algorithm includes determination of band, region, subregions and vectors. The algorithm is validated by simulation using MATLAB /SIMULINK for CSR 5, 7, 13 level CSMLI and for CSR fed CSI.

  8. Fault Ride Though Control of Photovoltaic Grid-connected Inverter with Current-limited Capability under Offshore Unbalanced Voltage Conditions

    DEFF Research Database (Denmark)

    Liu, Wenzhao; Guo, Xiaoqiang; Savaghebi, Mehdi;

    2016-01-01

    of the excessive current phenomenon with the conventional fault ride through control is discussed. The quantitative analysis of the current peak value is conducted and a new current-limiting control strategy is proposed to achieve the flexible power control and successful fault ride through in a safe current......The photovoltaic (PV) inverter installed on board experiences the excessive current stress in case of the offshore unbalanced voltage fault ride through (FRT), which significantly affects the operation reliability of the power supply system. In order to solve the problem, the inherent mechanism...

  9. Controllability of driven current profile in ECCD on ITER

    Energy Technology Data Exchange (ETDEWEB)

    Hamamatsu, K.; Fukuyama, A

    2001-01-01

    The controllability of current profile driven by the fundamental resonance of the O-mode wave is examined for the parameters of the Intermediate Aspect ratio Machine option of the International Thermonuclear Experimental Reactor (ITER). The driven current is numerically evaluated by using the full relativistic adjoint method which we have extended from the non-relativistic one. By changing both the toroidal and poloidal injection angles, the optimum direction to drive a current with maximum current density at the aimed position is obtained. The position of wave launching affects the optimum injection angles and the driven current profile. The dependence of driven current profile on beam divergence is also examined. When the beam is injected from the equatorial plane, the maximum current density is reduced and the width of current profile becomes wide in the outer region of r{>=}0.5a. The localized current profile is kept well within the region of r{>=}0.4a by injection from a location away from the equatorial plane.

  10. Suppression as a stereotype control strategy.

    Science.gov (United States)

    Monteith, M J; Sherman, J W; Devine, P G

    1998-01-01

    Recent research reveals that efforts to suppress stereotypic thoughts can backfire and produce a rebound effect, such that stereotypic thinking increases to a level that is even greater than if no attempt at stereotype control was initially exercised (e.g., Macrae, Bodenhausen, Milne, & Jetten, 1994). The primary goal of this article is to present an in-depth theoretical analysis of stereotype suppression that identifies numerous potential moderators of the effect of stereotype suppression on the likelihood of subsequent rebound. Our analysis of stereotype suppression focuses on two broad issues: the influence of level of prejudice and the influence of processing goals on the activation versus application of stereotypes. Although stereotype rebound occurs under some circumstances, we suggest that a complete understanding of this phenomenon requires consideration of the full array of possible moderating influences.

  11. Control Strategy for Three Phase Voltage Source PWM Rectifier Based on the Space Vector Modulation

    Directory of Open Access Journals (Sweden)

    MILOUD, Y.

    2010-08-01

    Full Text Available This paper proposes the space vector pulse width modulation (SVPWM control scheme for three-phase voltage source PWM rectifier. The control system based on SVPWM includes two PI controllers which are used to regulate the AC currents and DC-link voltage. The proposed control can stabilize the minimum of the systems storage function at the desired equilibrium point determined by unity power factor and sinusoidal current on the AC side, and constant output voltage on the DC side. So the stable state performance and robustness against the load�s disturbance of PWM rectifiers are both improved. The simulation result shows feasibility of this strategy.

  12. Controlling chemical dosing for sulfide mitigation in sewer networks using a hybrid automata control strategy.

    Science.gov (United States)

    Liu, Yiqi; Ganigué, Ramon; Sharma, Keshab; Yuan, Zhiguo

    2013-01-01

    Chemicals such as magnesium hydroxide (Mg(OH)2) and iron salts are widely used to control sulfide-induced corrosion in sewer networks composed of interconnected sewer pipe lines and pumping stations. Chemical dosing control is usually non-automatic and based on experience, thus often resulting in sewage reaching the discharge point receiving inadequate or even no chemical dosing. Moreover, intermittent operation of pumping stations makes traditional control theory inadequate. A hybrid automata-based (HA-based) control method is proposed in this paper to coordinate sewage pumping station operations by considering their states, thereby ensuring suitable chemical concentrations in the network discharge. The performance of the proposed control method was validated through a simulation study of a real sewer network using real sewage flow data. The physical, chemical and biological processes were simulated using the well-established SeweX model. The results suggested that the HA-based control strategy significantly improved chemical dosing control performance and sulfide mitigation in sewer networks, compared to the current common practice.

  13. Job monitoring on the WLCG scope: Current status and new strategy

    CERN Document Server

    Andreeva, J; Belov, S; Casey, J; Dvorak, F; Gaidioz, B; Karavakis, E; Kodolova, O; Kokoszkiewicz, L; Krenek, A; Lanciotti, E; Maier, J; Mulac, M; Rocha Da Cunha Rodrigues, D F; Rocha, R; Saiz, P; Sidorova, I; Sitera, J; Tikhonenko, E; Vaibhav, K; Vocu, M

    2010-01-01

    Job processing and data transfer are the main computing activities on the WLCG infrastructure. Reliable monitoring of the job processing on the WLCG scope is a complicated task due to the complexity of the infrastructure itself and the diversity of the currently used job submission methods. The paper will describe current status and the new strategy for the job monitoring on the WLCG scope, covering primary information sources, job status changes publishing, transport mechanism and visualization.

  14. Dynamics and stabilization of peak current-mode controlled buck converter with constant current load

    Institute of Scientific and Technical Information of China (English)

    冷敏瑞; 周国华; 张凯暾; 李振华

    2015-01-01

    The discrete iterative map model of peak current-mode controlled buck converter with constant current load (CCL), containing the output voltage feedback and ramp compensation, is established in this paper. Based on this model the com-plex dynamics of this converter is investigated by analyzing bifurcation diagrams and the Lyapunov exponent spectrum. The effects of ramp compensation and output voltage feedback on the stability of the converter are investigated. Experimental results verify the simulation and theoretical analysis. The stability boundary and chaos boundary are obtained under the theoretical conditions of period-doubling bifurcation and border collision. It is found that there are four operation regions in the peak current-mode controlled buck converter with CCL due to period-doubling bifurcation and border-collision bifur-cation. Research results indicate that ramp compensation can extend the stable operation range and transfer the operating mode, and output voltage feedback can eventually eliminate the coexisting fast-slow scale instability.

  15. Large Antenna Control Methods: Current Status and Future Trends

    Science.gov (United States)

    Rodriguez, G.; Lin, Y. H.; Milman, M. H.

    1985-01-01

    Current methods for control of large antennas, as well as future trends required for improved performance are addressed. Some of the target missions in which these methods would be used are: the Land Mobile Satellite System (LMSS) for communications; the Satellite Surveillance (SSS) for aircraft traffic control; the orbiting Very Long Baseline Interferometer (VLBI), or QUASAT, for radio astronomy; and the Large Deployable Reflector (LDR) for IR and submillimeter astronomy.

  16. A Critical Appraisal of Control Strategies for Soil-Transmitted Helminths.

    Science.gov (United States)

    Campbell, Suzy J; Nery, Susana V; McCarthy, James S; Gray, Darren J; Soares Magalhães, Ricardo J; Clements, Archie C A

    2016-02-01

    Interventions that lead to reductions in soil-transmitted helminths (STHs) include chemotherapy with anthelmintic drugs and improvements in water, sanitation, and hygiene (WASH). In this opinion article we aim to determine the evidence for optimal approaches for STH control. First we explore the evidence for the above interventions. We then appraise two integration strategies: current chemotherapy-oriented integrated neglected tropical disease (NTD) control and expanded 'multicomponent integration', which includes integrated chemotherapy, WASH, and other intervention strategies. While multicomponent integrated control may be an effective approach to sustainably reduce STH transmission, there is a need for evidence to prove the feasibility of this approach.

  17. UAV Robust Strategy Control Based on MAS

    Directory of Open Access Journals (Sweden)

    Jian Han

    2014-01-01

    Full Text Available A novel multiagent system (MAS has been proposed to integrate individual UAV (unmanned aerial vehicle to form a UAV team which can accomplish complex missions with better efficiency and effect. The MAS based UAV team control is more able to conquer dynamic situations and enhance the performance of any single UAV. In this paper, the MAS proposed and established combines the reacting and thinking abilities to be an initiative and autonomous hybrid system which can solve missions involving coordinated flight and cooperative operation. The MAS uses BDI model to support its logical perception and to classify the different missions; then the missions will be allocated by utilizing auction mechanism after analyzing dynamic parameters. Prim potential algorithm, particle swarm algorithm, and reallocation mechanism are proposed to realize the rational decomposing and optimal allocation in order to reach the maximum profit. After simulation, the MAS has been proved to be able to promote the success ratio and raise the robustness, while realizing feasibility of coordinated flight and optimality of cooperative mission.

  18. Brushless DC motor Drive during Speed regulation with Current Controller

    Directory of Open Access Journals (Sweden)

    Bhikshalu Manchala

    2015-04-01

    Full Text Available Brushless DC Motor (BLDC is one of the best electrical drives that have increasing popularity, due to their high efficiency, reliability, good dynamic response and very low maintenance. Due to the increasing demand for compact & reliable motors and the evolution of low cost power semiconductor switches and permanent magnet (PM materials, brushless DC motors become popular in every application from home appliances to aerospace industry. The conventional techniques for controlling the stator phase current in a brushless DC drive are practically effective in low speed and cannot reduce the commutation torque ripple in high speed range. This paper presents the PI controller for speed control of BLDC motor. The output of the PI controllers is summed and is given as the input to the current controller. The BLDC motor is fed from the inverter where the rotor position and current controller is the input. The complete model of the proposed drive system is developed and simulated using MATLAB/Simulink software. The operation principle of using component is analysed and the simulation results are presented in this to verify the theoretical analysis.

  19. Multi-Objective Predictive Balancing Control of Battery Packs Based on Predictive Current

    Directory of Open Access Journals (Sweden)

    Wenbiao Li

    2016-04-01

    Full Text Available Various balancing topology and control methods have been proposed for the inconsistency problem of battery packs. However, these strategies only focus on a single objective, ignore the mutual interaction among various factors and are only based on the external performance of the battery pack inconsistency, such as voltage balancing and state of charge (SOC balancing. To solve these problems, multi-objective predictive balancing control (MOPBC based on predictive current is proposed in this paper, namely, in the driving process of an electric vehicle, using predictive control to predict the battery pack output current the next time. Based on this information, the impact of the battery pack temperature caused by the output current can be obtained. Then, the influence is added to the battery pack balancing control, which makes the present degradation, temperature, and SOC imbalance achieve balance automatically due to the change of the output current the next moment. According to MOPBC, the simulation model of the balancing circuit is built with four cells in Matlab/Simulink. The simulation results show that MOPBC is not only better than the other traditional balancing control strategies but also reduces the energy loss in the balancing process.

  20. A Lyapunov Stability Theory-Based Control Strategy for Three-Level Shunt Active Power Filter

    Directory of Open Access Journals (Sweden)

    Yijia Cao

    2017-01-01

    Full Text Available The three-phase three-wire neutral-point-clamped shunt active power filter (NPC-SAPF, which most adopts classical closed-loop feedback control methods such as proportional-integral (PI, proportional-resonant (PR and repetitive control, can only output 1st–25th harmonic currents with 10–20 kHz switching frequency. The reason for this is that the controller design must make a compromise between system stability and harmonic current compensation ability under the condition of less than 20 kHz switching frequency. To broaden the bandwidth of the compensation current, a Lyapunov stability theory-based control strategy is presented in this paper for NPC-SAPF. The proposed control law is obtained by constructing the switching function on the basis of the mathematical model and the Lyapunov candidate function, which can avoid introducing closed-loop feedback control and keep the system globally asymptotically stable. By means of the proposed method, the NPC-SAPF has compensation ability for the 1st–50th harmonic currents, the total harmonic distortion (THD and each harmonic content of grid currents satisfy the requirements of IEEE Standard 519-2014. In order to verify the superiority of the proposed control strategy, stability conditions of the proposed strategy and the representative PR controllers are compared. The simulation results in MATLAB/Simulink (MathWorks, Natick, MA, USA and the experimental results obtained on a 6.6 kVA NPC-SAPF laboratory prototype validate the proposed control strategy.

  1. Control Mechanism Strategies for Spin-Stabilized Projectiles

    Science.gov (United States)

    2008-09-01

    from more traditional smart weapons, thus warranting basic research into guidance and control strategies. Conventional methods include canards, fins...moment arms. AACC XNXN  . (1) 14 CG CP Nose Base Figure 13. Relationship between maneuver footprint and control axial location. XC CG MC

  2. Research on Hybrid-excited Flux-switching Machine and the Current Vector Control Strategy%并列式混合励磁磁通切换型电机及其电流矢量控制策略研究

    Institute of Scientific and Technical Information of China (English)

    朱婷婷; 邓智泉; 王宇

    2012-01-01

    As a solution to the magnetic field regulation problem in flux-switching permanent magnet motors, this paper presents a novel parallel hybrid excited flux-switching machine, which takes on high power density, intrinsic sinusoidal back EMF, and good field regulation ability. Based on field simulation, this paper made detailed analysis on the inductance characteristics and the field-weakening performance established the mathematical model and brought out a new current vector control strategy. The results show that the strategy achieved good static characteristics as well as maximum torque/copper loss ratio. A principle prototype was built to validate its excellent field regulation performance as well as the effectiveness of the presented control strategy.%为解决永磁磁通切换式电机磁场调节困难的问题,研究了一种新型并列式混合励磁磁通切换型(parallelhybridexcitedflux.switching,PHEFSl电机,该电机继承了永磁磁通切换电机功率密度高、反电势正弦等优势,且具有较强的对称调磁能力。结合磁路仿真对该电机电感特性和弱磁性能进行了理论分析,建立了PHEFS电机的数学模型,提出了id=0最大转矩铜耗比电流矢量控制策略,通过对励磁电流和电枢电流的合理分配,在保证静态特性的同时,达到最大转矩铜耗比,以提高电机的运行效率。原理样机的实验结果证明了该电机良好的调磁性能及所提算法的合理性与有效性。

  3. A semi-decentralized control strategy for urban traffic

    OpenAIRE

    Farhi, Nadir; Nguyen Van Phu, Cyril; AMIR, Mouna; Haj Salem, Habib; LEBACQUE, Jean Patrick

    2015-01-01

    EWGT - Euro Working Group on Transportation, Delft, PAYS-BAS, 14-/07/2015 - 16/07/2015; We present in this article a semi-decentralized approach for urban traffic control, based on the TUC (Traffic responsive Urban Control) strategy. We assume that the control is centralized as in the TUC strategy, but we introduce a contention time window inside the cycle time, where antagonistic stages alternate a priority rule. The priority rule is set by applying green colours for given stages and yellow ...

  4. Control of bootstrap current in the pedestal region of tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Shaing, K. C. [Institute for Space and Plasma Sciences, National Cheng Kung University, Tainan City 70101, Taiwan (China); Department of Engineering Physics, University of Wisconsin, Madison, Wisconsin 53796 (United States); Lai, A. L. [Institute for Space and Plasma Sciences, National Cheng Kung University, Tainan City 70101, Taiwan (China)

    2013-12-15

    The high confinement mode (H-mode) plasmas in the pedestal region of tokamaks are characterized by steep gradient of the radial electric field, and sonic poloidal U{sub p,m} flow that consists of poloidal components of the E×B flow and the plasma flow velocity that is parallel to the magnetic field B. Here, E is the electric field. The bootstrap current that is important for the equilibrium, and stability of the pedestal of H-mode plasmas is shown to have an expression different from that in the conventional theory. In the limit where ‖U{sub p,m}‖≫ 1, the bootstrap current is driven by the electron temperature gradient and inductive electric field fundamentally different from that in the conventional theory. The bootstrap current in the pedestal region can be controlled through manipulating U{sub p,m} and the gradient of the radial electric. This, in turn, can control plasma stability such as edge-localized modes. Quantitative evaluations of various coefficients are shown to illustrate that the bootstrap current remains finite when ‖U{sub p,m}‖ approaches infinite and to provide indications how to control the bootstrap current. Approximate analytic expressions for viscous coefficients that join results in the banana and plateau-Pfirsch-Schluter regimes are presented to facilitate bootstrap and neoclassical transport simulations in the pedestal region.

  5. Parent Retrospective Recollections of Bullying and Current Views, Concerns, and Strategies to Cope with Children's Bullying

    Science.gov (United States)

    Cooper, Leigh A.; Nickerson, Amanda B.

    2013-01-01

    In this study, parent history of bullying was examined in terms of general involvement with bullying, specific types of bullying experienced, level of hurtfulness associated with the experience, and when bullying occurred. Parent current views, levels of concern, and strategies used to cope with bullying were also evaluated. Finally, the…

  6. Adaptive Landing Gear: Optimum Control Strategy and Potential for Improvement

    Directory of Open Access Journals (Sweden)

    Grzegorz Mikułowski

    2009-01-01

    Full Text Available An adaptive landing gear is a landing gear (LG capable of active adaptation to particular landing conditions by means of controlled hydraulic force. The objective of the adaptive control is to mitigate the peak force transferred to the aircraft structure during touch-down, and thus to limit the structural fatigue factor. This paper investigates the ultimate limits for improvement due to various strategies of active control. Five strategies are proposed and investigated numerically using a~validated model of a real, passive landing gear as a reference. Potential for improvement is estimated statistically in terms of the mean and median (significant peak strut forces as well as in terms of the extended safe sinking velocity range. Three control strategies are verified experimentally using a laboratory test stand.

  7. Distributed-dispersed renewable energy systems and novel control strategies

    Science.gov (United States)

    Aljankawey, Abdualah S.

    Renewable green-energy systems are re-emerging as viable economic alternative sources of environmentally safe power generation in place of conventional fossil fuels. In terms of power quality and safety, this research investigates a number of renewable green-energy (wind, photovoltaic and fuel cells) interface schemes and control strategies that ensure maximum energy utilization, voltage and frequency stabilization and minimum impact on the host electric grid systems. The research key objectives are to study efficient and robust renewable energy converter schemes with associated control strategies and validate their operations for both stand-alone and electric utility grid interfacing. The research work investigates both stand-alone and grid connected renewable green-energy utilization schemes with a number of power electronic converter topologies and robust control schemes for both dispersed and hybrid renewable energy systems. Different sample study systems and control strategies are digitally simulated and fully validated using the MATLAB-Simulink-SimPower environment.

  8. A Distributed Control Strategy for an Isolated Residential DC Microgrid

    Directory of Open Access Journals (Sweden)

    Guiting Xue

    2012-09-01

    Full Text Available A low-voltage unipolar type dc microgrid , which includes photovoltaic (PV arrays, Fuel Cells (FCs, batteries and power electronic interfaces, is presented in this study. In order to provide the plug-and-play feature, a distributed control strategy based on Dc Bus Signaling (DBS is studied. According to the proposed control strategy, the operations of the dc microgrid are categorized into three modes: batteries charging/discharging, Constant Voltage (CV generation and FCs discharging. These three kinds of modes can be automatically switched by using DBS. Control methods of converters for different microsources are also addressed. Simulation results are provided to verify the effectiveness of the proposed control strategy.

  9. Study of a control strategy for grid side converter in doubly- fed wind power system

    Science.gov (United States)

    Zhu, D. J.; Tan, Z. L.; Yuan, F.; Wang, Q. Y.; Ding, M.

    2016-08-01

    The grid side converter is an important part of the excitation system of doubly-fed asynchronous generator used in wind power system. As a three-phase voltage source PWM converter, it can not only transfer slip power in the form of active power, but also adjust the reactive power of the grid. This paper proposed a control approach for improving its performance. In this control approach, the dc voltage is regulated by a sliding mode variable structure control scheme and current by a variable structure controller based on the input output linearization. The theoretical bases of the sliding mode variable structure control were introduced, and the stability proof was presented. Switching function of the system has been deduced, sliding mode voltage controller model has been established, and the output of the outer voltage loop is the instruction of the inner current loop. Affine nonlinear model of two input two output equations on d-q axis for current has been established its meeting conditions of exact linearization were proved. In order to improve the anti-jamming capability of the system, a variable structure control was added in the current controller, the control law was deduced. The dual-loop control with sliding mode control in outer voltage loop and linearization variable structure control in inner current loop was proposed. Simulation results demonstrate the effectiveness of the proposed control strategy even during the dc reference voltage and system load variation.

  10. Current Control of Grid Converters Connected with Series AC Capacitor

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang

    2015-01-01

    The series ac capacitor has recently been used with the transformerless grid-connected converters in the distribution power grids. The capacitive characteristic of the resulting series LC filter restricts the use of conventional synchronous integral or stationary resonant current controllers. Thus...

  11. High performance current controller for particle accelerator magnets supply

    DEFF Research Database (Denmark)

    Maheshwari, Ram Krishan; Bidoggia, Benoit; Munk-Nielsen, Stig;

    2013-01-01

    The electromagnets in modern particle accelerators require high performance power supply whose output is required to track the current reference with a very high accuracy (down to 50 ppm). This demands very high bandwidth controller design. A converter based on buck converter topology is used in ...

  12. Procoagulant control strategies for the human blood clotting process.

    Science.gov (United States)

    Laurino, Marco; Menara, Tommaso; Stella, Alessandro; Betta, Monica; Landi, Alberto

    2015-08-01

    This paper describes the comparison between two drug control strategies to hemophilia A. To emulate blood clotting and the pathological condition of hemophilia, a mathematical model composed by 14 ordinary differential equations is considered. We adopt a variable structure non-linear PID approach and a Model Predictive Control in order to control the dosage of procoagulant factor used in the treatment of hemophiliac patient. The two control actions are sampled for a practical application. Finally, we discuss and compare the results of the two control approaches, introducing a suited control index (eINR).

  13. Structure and Control Strategies of Fuel Cell Vehicle

    Institute of Scientific and Technical Information of China (English)

    宋建国; 张承宁; 孙逢春; 钟秋海

    2004-01-01

    The structure and kinds of the fuel cell vehicle (FCV) and the mathematical model of the fuel cell processor are discussed in detail. FCV includes many parts: the fuel cell thermal and water management, fuel supply, air supply and distribution, AC motor drive, main and auxiliary power management, and overall vehicle control system. So it requires different kinds of control strategies, such as the PID method, zero-pole method, optimal control method, fuzzy control and neural network control. Along with the progress of control method, the fuel cell vehicle's stability and reliability is up-and-up. Experiment results show FCV has high energy efficiency.

  14. Current available strategies to mitigate greenhouse gas emissions in livestock systems: an animal welfare perspective.

    Science.gov (United States)

    Llonch, P; Haskell, M J; Dewhurst, R J; Turner, S P

    2017-02-01

    Livestock production is a major contributor to greenhouse gas (GHG) emissions, so will play a significant role in the mitigation effort. Recent literature highlights different strategies to mitigate GHG emissions in the livestock sector. Animal welfare is a criterion of sustainability and any strategy designed to reduce the carbon footprint of livestock production should consider animal welfare amongst other sustainability metrics. We discuss and tabulate the likely relationships and trade-offs between the GHG mitigation potential of mitigation strategies and their welfare consequences, focusing on ruminant species and on cattle in particular. The major livestock GHG mitigation strategies were classified according to their mitigation approach as reducing total emissions (inhibiting methane production in the rumen), or reducing emissions intensity (Ei; reducing CH4 per output unit without directly targeting methanogenesis). Strategies classified as antimethanogenic included chemical inhibitors, electron acceptors (i.e. nitrates), ionophores (i.e. Monensin) and dietary lipids. Increasing diet digestibility, intensive housing, improving health and welfare, increasing reproductive efficiency and breeding for higher productivity were categorized as strategies that reduce Ei. Strategies that increase productivity are very promising ways to reduce the livestock carbon footprint, though in intensive systems this is likely to be achieved at the cost of welfare. Other strategies can effectively reduce GHG emissions whilst simultaneously improving animal welfare (e.g. feed supplementation or improving health). These win-win strategies should be strongly supported as they address both environmental and ethical sustainability. In order to identify the most cost-effective measures for improving environmental sustainability of livestock production, the consequences of current and future strategies for animal welfare must be scrutinized and contrasted against their effectiveness

  15. Dynamic Feedback Controlling Chaos in Current-Mode Boost Converter

    Institute of Scientific and Technical Information of China (English)

    LU Wei-Guo; ZHOU Luo-Wei; LUO Quan-Ming

    2007-01-01

    A method for the control of chaos in the current-mode boost converter is presented by using the first-order dynamic feedback control. The feedback part consists of a resistance and a capacitance in series. The system to be controlled is treated as a third-order model, and then the discrete mapping model is obtained by using the data-sampling method. By analysing the position of the maximum norm eigenvalue, the stable range of feedback gain is ascertained out and its optimization is also carried out. Finally, the results of simulation and experiment confirm the correctness of the theoretical analysis and the validity of the proposed means.

  16. Novel Control Strategy for VSI and CSI Active Filters and Comparing These Two Types of Filters

    Directory of Open Access Journals (Sweden)

    Gholam Reza Arab

    2014-10-01

    Full Text Available Recently to eliminate the harmonics and improve the power factor of the power networks, much attention has been attracted to active filters. The advantages of these filters are lower volume and their better compensating characteristics than the passive filters. In conventional sliding mode controllers, the source current waveform is fluctuated in near to zero values. In this paper, using a new sliding technique, lower Total Harmonic Distortion (THD in source current is obtained and the current waveform is improved. As well as, two novel control strategies for two types of active filters, VSI and CSI is proposed and then these two types of filters are compared to reduce THD value of source current.The proposed controlled strategies are simulated by MATLAB/Simulink. The Simulation results confirm that the proposed strategies reduce the THD of source current more than other strategies, and active filter based on CSI has a better performance than active filter based on VSI with a dead time area (for avoiding short circuit of the source in high powers.

  17. Indirect thermal control for improved reliability of Modular Multilevel Converter by utilizing circulating current

    DEFF Research Database (Denmark)

    Dowlatabadi, Mohammadkazem Bakhshizadeh; Ma, Ke; Loh, Poh Chiang;

    2015-01-01

    Modular Multilevel Converter (MMC) has recently become a popular multilevel topology for high-power applications, where the reliability performance is a crucial design consideration. In this paper the impacts of the circulating current in the MMC to the loss and thermal loading of power...... loading of the power devices, and by proper controlling the amount of circulating current, the temperature fluctuation or thermal cycling in the power device can be relieved, and thereby contributing to improved reliability performance according to many lifetime models/testing results for power devices....... semiconductor devices are comprehensively investigated. Also a novel control strategy by utilizing the circulating current is proposed to enhance the reliability performance of MMC in order to limit the amplitude of thermal cycles. It is concluded that the circulating current may change the losses and thermal...

  18. Virtual-Impedance-Based Control for Voltage-Source and Current-Source Converters

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Li, YunWei; Blaabjerg, Frede;

    2015-01-01

    The virtual impedance concept is increasingly used for the control of power electronic systems. Generally, the virtual impedance loop can either be embedded as an additional degree of freedom for active stabilization and disturbance rejection, or be employed as a command reference generator...... for the converters to provide ancillary services. This paper presents an overview of the virtual-impedance-based control strategies for voltage-source and current-source converters. The control output impedance shaping attained by the virtual impedances is generalized first using the impedance-based models...

  19. Reading comprehension metacognitive strategies as a means for controlling behavior

    Directory of Open Access Journals (Sweden)

    Dinorah Aladina Caballero López

    2014-07-01

    Full Text Available Textual comprehension implies the use of various metacognitive strategies by the students when they have to face a text to be competent readers. That is why the objective of this article is to illustrate the application of metacognitive strategies in order to achieve an efficient textual comprehension, taking into account the self – regulation the student exerts over his own learning process. It is applied as the main method historical-logical studies based on a professional-researching systematic practice; at the same time observation is largely used. The main result is the introduction of metacognitive strategies in reading comprehension, which subsequently favor the self-control of personal behavior. The article is the result of a research project sponsored by the department of Special Education. Key words: reading comprehension, metacognitive strategies, behavior self-control.

  20. Evaluation of alternative management strategies of muskrat Ondatra zibethicus population control using a population model

    NARCIS (Netherlands)

    Bos, Daan; Ydenberg, Ron

    2011-01-01

    Muskrats Ondatra zibethicus are considered a pest species in the Netherlands, and a year-round control programme is in effect. Currently, the agency responsible for the management of muskrat populations in the Netherlands (the LCCM) is preparing for field studies to compare alternative strategies of

  1. Development of a vehicle load control strategy for Malawi for the period 2016 to 2020

    CSIR Research Space (South Africa)

    Roux, MP

    2016-07-01

    Full Text Available Strategy and development of a five-year implementation plan for significantly improving the Directorate’s current capacity to effectively manage and enforce axle load control. Specific objectives were to: a) Assist the DRTSS to undertake an extensive...

  2. Development of a current-controlled defibrillator for clinical tests.

    Science.gov (United States)

    Fischer, M; Schönegg, M; Schöchlin, J; Bolz, A

    2002-01-01

    The work presented here is only a part of the development for a new current-controlled defibrillator. In the diploma thesis "Development and construction of a current-controlled defibrillator for clinical tests" the most important part was the control and safety of the defibrillator. To ensure a safe circuit design, a risk-analysis and a Failure Mode and Effects Analysis (FMEA) were necessary. Another major part was the programming of a microcontroller in embedded C and a programmable logic device in Very High Speed Integrated Circuit Description Language (VHDL). The circuit had to be constructed, and the defibrillator was optically decoupled from the laptop for safety reasons. The waveform-data can be transmitted to the microcontroller from the laptop, and the logged data is then transmitted back.

  3. A NEW STOCHASTIC OPTIMAL CONTROL STRATEGY FOR HYSTERETIC MR DAMPERS

    Institute of Scientific and Technical Information of China (English)

    YingZuguang; NiYiqing; KoJanming

    2004-01-01

    A new stochastic optimal control strategy for randomly excited quasi-integrable Hamiltonian systems using magneto-theological (MR) dampers is proposed. The dynamic behavior of an MR damper is characterized by the Bouc-Wen hysteretic model. The control force produced by the MR damper is separated into a passive part incorporated in the uncontrolled system and a semi-active part to be determined. The system combining the Bouc-Wen hysteretic force is converted into an equivalent non-hysteretic nonlinear stochastic control system. Then Ito stochastic differential equations are derived from the equivalent system by using the stochastic averaging method. A dynamical programming equation for the controlled diffusion processes is established based on the stochastic dynamical programming principle. The non-clipping nonlinear optimal control law is obtained for a certain performance index by minimizing the dynamical programming equation. Finally, an example is given to illustrate the application and effectiveness of the proposed control strategy.

  4. Invasive mechanism and control strategy of Ageratina adenophora (Sprengel)

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In order to ascertain the invasive mechanism and control strategy of the invasive Crofton weed, Ageratina adenophora, its ecological adaptability and population differentiation,the formation of single dominant population, displacement of native plants and sustainable management strategies were investigated. The present results helped to clarify and explain such issues as the adaptability post invasion,interaction and competition between inter-and intra-species and community resistance, thereby providing important references to researches on other invasive alien species.

  5. Alternating Current All-electrical Gun Control System in Tanks

    Directory of Open Access Journals (Sweden)

    Zang Kemao

    2004-07-01

    Full Text Available The ac all-electrical gun control system is composed of permanent magnetic synchronous machine-drive control systems and the ball-screw by replacing the complicated electrohydraulic systems. At the same time, the variable-structure system with sliding modes makes the gun control systems to have higher performances using the only rate flexure gyroscope. Thereby, vehicle hull gyroscope and angular gyroscope are left out.The new ac all-electrical gun control systems developed are reduced by 40 per cent in weight, decreased by 30 per cent in volume, increased by 35 per cent in efficiency, and enhanced by three times in service life as compared to the current gun control systems.

  6. Control Strategies for the DAB Based PV Interface System.

    Science.gov (United States)

    El-Helw, Hadi M; Al-Hasheem, Mohamed; Marei, Mostafa I

    2016-01-01

    This paper presents an interface system based on the Dual Active Bridge (DAB) converter for Photovoltaic (PV) arrays. Two control strategies are proposed for the DAB converter to harvest the maximum power from the PV array. The first strategy is based on a simple PI controller to regulate the terminal PV voltage through the phase shift angle of the DAB converter. The Perturb and Observe (P&O) Maximum Power Point Tracking (MPPT) technique is utilized to set the reference of the PV terminal voltage. The second strategy presented in this paper employs the Artificial Neural Network (ANN) to directly set the phase shift angle of the DAB converter that results in harvesting maximum power. This feed-forward strategy overcomes the stability issues of the feedback strategy. The proposed PV interface systems are modeled and simulated using MATLAB/SIMULINK and the EMTDC/PSCAD software packages. The simulation results reveal accurate and fast response of the proposed systems. The dynamic performance of the proposed feed-forward strategy outdoes that of the feedback strategy in terms of accuracy and response time. Moreover, an experimental prototype is built to test and validate the proposed PV interface system.

  7. Control Strategies for the DAB Based PV Interface System

    Science.gov (United States)

    El-Helw, Hadi M.; Al-Hasheem, Mohamed; Marei, Mostafa I.

    2016-01-01

    This paper presents an interface system based on the Dual Active Bridge (DAB) converter for Photovoltaic (PV) arrays. Two control strategies are proposed for the DAB converter to harvest the maximum power from the PV array. The first strategy is based on a simple PI controller to regulate the terminal PV voltage through the phase shift angle of the DAB converter. The Perturb and Observe (P&O) Maximum Power Point Tracking (MPPT) technique is utilized to set the reference of the PV terminal voltage. The second strategy presented in this paper employs the Artificial Neural Network (ANN) to directly set the phase shift angle of the DAB converter that results in harvesting maximum power. This feed-forward strategy overcomes the stability issues of the feedback strategy. The proposed PV interface systems are modeled and simulated using MATLAB/SIMULINK and the EMTDC/PSCAD software packages. The simulation results reveal accurate and fast response of the proposed systems. The dynamic performance of the proposed feed-forward strategy outdoes that of the feedback strategy in terms of accuracy and response time. Moreover, an experimental prototype is built to test and validate the proposed PV interface system. PMID:27560138

  8. Enhanced Predictive Current Control of Three-Phase Grid-Tied Reversible Converters with Improved Switching Patterns

    Directory of Open Access Journals (Sweden)

    Zhanfeng Song

    2016-01-01

    Full Text Available A predictive current control strategy can realize flexible regulation of three-phase grid-tied converters based on system behaviour prediction and cost function minimization. However, when the predictive current control strategy with conventional switching patterns is adopted, the predicted duration time for voltage vectors turns out to be negative in some cases, especially under the conditions of bidirectional power flows and transient situations, leading to system performance deteriorations. This paper aims to clarify the real reason for this phenomenon under bidirectional power flows, i.e., rectifier mode and inverter mode, and, furthermore, seeks to propose effective solutions. A detailed analysis of instantaneous current variations under different conditions was conducted. An enhanced predictive current control strategy with improved switching patterns was then proposed. An experimental platform was built based on a commercial converter produced by Danfoss, and moreover, relative experiments were carried out, confirming the superiority of the proposed scheme.

  9. Tsetse Control and Gambian Sleeping Sickness; Implications for Control Strategy.

    Directory of Open Access Journals (Sweden)

    Inaki Tirados

    Full Text Available Gambian sleeping sickness (human African trypanosomiasis, HAT outbreaks are brought under control by case detection and treatment although it is recognised that this typically only reaches about 75% of the population. Vector control is capable of completely interrupting HAT transmission but is not used because it is considered too expensive and difficult to organise in resource-poor settings. We conducted a full scale field trial of a refined vector control technology to determine its utility in control of Gambian HAT.The major vector of Gambian HAT is the tsetse fly Glossina fuscipes which lives in the humid zone immediately adjacent to water bodies. From a series of preliminary trials we determined the number of tiny targets required to reduce G. fuscipes populations by more than 90%. Using these data for model calibration we predicted we needed a target density of 20 per linear km of river in riverine savannah to achieve >90% tsetse control. We then carried out a full scale, 500 km2 field trial covering two HAT foci in Northern Uganda to determine the efficacy of tiny targets (overall target density 5.7/km2. In 12 months, tsetse populations declined by more than 90%. As a guide we used a published HAT transmission model and calculated that a 72% reduction in tsetse population is required to stop transmission in those settings.The Ugandan census suggests population density in the HAT foci is approximately 500 per km2. The estimated cost for a single round of active case detection (excluding treatment, covering 80% of the population, is US$433,333 (WHO figures. One year of vector control organised within the country, which can completely stop HAT transmission, would cost US$42,700. The case for adding this method of vector control to case detection and treatment is strong. We outline how such a component could be organised.

  10. The bridge-type fault current controller--a new facts controller

    Energy Technology Data Exchange (ETDEWEB)

    Boenig, Heinrich J.; Mielke, C. H. (Charles H.); Burley, B. L. (Burt L.); Chen, Hong; Waynert, J. A. (Joseph A.); Willis, J. O. (Jeffrey O.)

    2002-01-01

    The operation of a novel current controller, which can also function as a fault current limiter and as a solid-state ac circuit breaker, is presented. The controller, which consists of a thyristor bridge, an inductor, and an optional bias power supply, is installed in series with the voltage source and the load, For load current values smaller than a preset value, the inductor of the current controller presents no impedance to the ac current flow. For values higher than the preset current value, the inductor is switched automatically into the ac circuit and limits the amount of current flow. Theoretical results in the form of circuit simulations and experimental results with a single-phase unit, operating on a 13.7 kV three-phase system with peak short-circuit currents of 3140 Arms, are presented.

  11. Low Voltage Ride-through in DFIG Wind Generators by Controlling the Rotor Current without Crowbars

    Directory of Open Access Journals (Sweden)

    Jaime Rodríguez Arribas

    2014-01-01

    Full Text Available Among all the different types of electric wind generators, those that are based on doubly fed induction generators, or DFIG technology, are the most vulnerable to grid faults such as voltage sags. This paper proposes a new control strategy for this type of wind generator, that allows these devices to withstand the effects of a voltage sag while following the new requirements imposed by grid operators. This new control strategy makes the use of complementary devices such as crowbars unnecessary, as it greatly reduces the value of currents originated by the fault. This ensures less costly designs for the rotor systems as well as a more economic sizing of the necessary power electronics. The strategy described here uses an electric generator model based on space-phasor theory that provides a direct control over the position of the rotor magnetic flux. Controlling the rotor magnetic flux has a direct influence on the rest of the electrical variables enabling the machine to evolve to a desired work point during the transient imposed by the grid disturbance. Simulation studies have been carried out, as well as test bench trials, in order to prove the viability and functionality of the proposed control strategy.

  12. Innovative current mode voltage mode control for distributed energy generation static systems; Controle inovador modo corrente modo tensao para sistemas estaticos de geracao distribuida de energia

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira Junior, Azauri Albano de; Maciel, Carlos Dias; Cichy, Elineri Cassia C.; Gongora, Vicente de Lima [Universidade de Sao Paulo (EESC/USP), Sao Carlos, SP (Brazil). Escola de Engenharia], Emails: azaurijr@sel.eesc.usp.br, maciel@sel.eesc.usp.br, elineri@uol.com.br, vicente@ldapalm.com.br; Barbosa, Lucio dos Reis [Universidade Estadual de Londrina (UEL), PR (Brazil)], Email: lbarbosa@uel.br; Pereira, Adriano Alves [Universidade Federal de Uberlandia (UFU), MG (Brazil)], Email: aapereira@ufu.br

    2006-07-01

    This work focuses on control of power inverter technologies for connecting any possible Dc energy system to a single-phase using a Current Mode Voltage Mode Control-CMVMC. In this way a CMVMC can control only one power inverter in two operation modes. In current mode the control inject the active power in the utility and voltage control keeping loads always on with energy from the alternative DC sources. When installed near big centers the control will choose the correctly operation or current mode or voltage mode depend on if the utility is present or no. This advanced, robust control strategies can determine the maximum on-line limit current from the DC energy, without DC current component and also free of island operation. The feasibility of this new control was digitally simulated and implemented in analogic way. (author)

  13. Stator Current Harmonic Control with Resonant Controller for Doubly Fed Induction Generator

    DEFF Research Database (Denmark)

    Liu, Changjin; Blaabjerg, Frede; Chen, Wenjie;

    2012-01-01

    Voltage harmonics in the grid can introduce stator current harmonics in a doubly fed induction generator (DFIG) wind turbine system, which may potentially impact the generated power quality. Therefore, wind turbine current controllers need to be designed to eliminate the impact of grid voltage...... rotor current control loop for harmonic suppression. The overall control scheme is implemented in dq frame. Based on a mathematical model of the DFIG control system, the effects on system stability using the resonant controller, an analysis of the steady-state error, and the dynamic performance...

  14. Mothers' teaching strategies and children's effortful control: a longitudinal study.

    Science.gov (United States)

    Eisenberg, Nancy; Vidmar, Masa; Spinrad, Tracy L; Eggum, Natalie D; Edwards, Alison; Gaertner, Bridget; Kupfer, Anne

    2010-09-01

    Findings on the relation of maternal verbal teaching strategies to children's effortful control (EC; i.e., self-regulation) are limited in quantity and somewhat inconsistent. In this study, children's EC was assessed at 18, 30, and 42 months (ns = 255, 229, and 209, respectively) with adults' reports and a behavioral measure. Mothers' verbal teaching strategies were assessed while the mother and child worked on a task together. Children's general vocabulary also was measured. In a structural panel model taking into account prior levels of constructs and correlations within time, as well as the relations of EC and teaching strategies to children's vocabulary, socioeconomic status, age, and sex of the child, 18-month EC positively predicted mothers' 30-month cognitive assistance and questioning strategies and negatively predicted 30-month maternal directive strategies. In addition, high 30-month EC predicted greater 42-month maternal cognitive assistance and fewer directive strategies. Thus, mothers' teaching strategies were predicted by individual differences in self-regulatory skills, supporting potential evocative child effects on mothers' teaching strategies.

  15. Advanced induction motor drive control with single current sensor

    Directory of Open Access Journals (Sweden)

    Adžić Evgenije M.

    2016-01-01

    Full Text Available This paper proposes induction motor drive control method which uses minimal number of sensors, providing only DC-link current as a feedback signal. Improved DC-link current sampling scheme and modified asymmetrical switching pattern cancels characteristic waveform errors which exist in all three reconstructed motor line-currents. Motor linecurrent harmonic content is reduced to an acceptable level, eliminating torque and speed oscillations which were inherent for conventional single sensor drives. Consequently, use of single current sensor and line-current reconstruction technique is no longer acceptable only for low and medium performance drives, but also for drives where priority is obtaining a highly accurate, stable and fast response. Proposed control algorithm is validated using induction motor drive hardware prototype based on TMS320F2812 digital signal processor. [Projekat Ministarstva nauke Republike Srbije, br. III 042004 and by the Provincial Secretariat for Science and Technological Development of AP Vojvodina under contract No. 114-451-3508/2013-04

  16. Control of optically induced currents in semiconductor crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kohli, Kapil Kumar

    2010-06-01

    The generation and control of optically induced currents has the potential to become an important building block for optical computers. Here, shift and rectification currents are investigated that emerge from a divergence of the optical susceptibility. It is known that these currents react to the shape of the impinging laser pulse, and especially to the shape of the pulse envelope. The main goal is the systematic manipulation of the pulse envelope with an optical pulse shaper that is integrated into a standard THz emission setup. The initial approach, the chirping of the laser pulse only has a weak influence on the envelope and the currents. Instead, a second approach is suggested that uses the combined envelope of a phase-stable pulse-pair as a parameter. In a laser pulse, the position of the maxima of the electrical field and the pulse envelope are shifted relative to each other. This shift is known as the Carrier-Envelope Phase (CEP). It is a new degree of freedom that is usually only accessible in specially stabilized systems. It is shown, that in a phase-stable pulse-pair, at least the relative CEP is usable as a new degree of freedom. It has a great influence on the shape of the pulse envelope and thus on the current density. It is shown that this approach enables the coherent control of the current density. The experiments are corroborated by a theoretical model of the system. The potential of this approach is demonstrated in an application. A framework is presented that uses an iterative genetic algorithm to create arbitrarily shaped THz traces. The algorithm controls the optical pulse shaper, and varies the phase of the impinging laser pulses until the desired target trace is found. (orig.)

  17. Turbine Control Strategies for Wind Farm Power Optimization

    DEFF Research Database (Denmark)

    Mirzaei, Mahmood; Göçmen Bozkurt, Tuhfe; Giebel, Gregor

    2015-01-01

    In recent decades there has been increasing interest in green energies, of which wind energy is the most important one. In order to improve the competitiveness of the wind power plants, there are ongoing researches to decrease cost per energy unit and increase the efficiency of wind turbines...... and wind farms. One way of achieving these goals is to optimize the power generated by a wind farm. One optimization method is to choose appropriate operating points for the individual wind turbines in the farm. We have made three models of a wind farm based on three difference control strategies....... Basically, the control strategies determine the steady state operating points of the wind turbines. Except the control strategies of the individual wind turbines, the wind farm models are similar. Each model consists of a row of 5MW reference wind turbines. In the models we are able to optimize...

  18. [Integrated prevention and control strategy for dengue in Mesoamerica].

    Science.gov (United States)

    Gómez-Dantés, Héctor; San Martín, José Luis; Danis-Lozano, Rogelio; Manrique-Saide, Pablo

    2011-01-01

    Dengue in the Americas is a public health problem in ascent. The control strategies have not been effective when sustained in the intensive use of insecticides and poor community participation. The Mesoamerican Initiative for the Prevention and the Integrated Control of Dengue synthesizes the works generated by the Integrated Strategy of the Pan-American Health Organization (PAHO) and the risks stratification strategy designed by the countries of the Mesoamerican region. The objective is to progressively reduce the incidence of dengue cases until a 50% reduction is reached over a five years period. This document describes the elements for the risk stratification, the activities for prevention and control organized by levels of intensity and frequency and the indicators used to pursuit the objectives. To face the dispersion of the problem a concentration of efforts for control in the areas of greater risk is presented; the opportunity in the detection of cases is highlighted to tackle the fast dissemination of the infection; focus on the most productive breeding sites is proposed to battle against the vast dissemination of the breeding sites; and the severity of the infection must be addressed by capable clinical human resources. This strategy was designed along with the national representatives of the control programs to create master plans that provided the basis for the integrated prevention and control of dengue in the Mesoamerican region.

  19. High Level Waste (HLW) Feed Process Control Strategy

    Energy Technology Data Exchange (ETDEWEB)

    STAEHR, T.W.

    2000-06-14

    The primary purpose of this document is to describe the overall process control strategy for monitoring and controlling the functions associated with the Phase 1B high-level waste feed delivery. This document provides the basis for process monitoring and control functions and requirements needed throughput the double-shell tank system during Phase 1 high-level waste feed delivery. This document is intended to be used by (1) the developers of the future Process Control Plan and (2) the developers of the monitoring and control system.

  20. Innovation in Active Vibration Control Strategy of Intelligent Structures

    Directory of Open Access Journals (Sweden)

    A. Moutsopoulou

    2014-01-01

    Full Text Available Large amplitudes and attenuating vibration periods result in fatigue, instability, and poor structural performance. In light of past approaches in this field, this paper intends to discuss some innovative approaches in vibration control of intelligent structures, particularly in the case of structures with embedded piezoelectric materials. Control strategies are presented, such as the linear quadratic control theory, as well as more advanced theories, such as robust control theory. The paper presents sufficiently a recognizable advance in knowledge of active vibration control in intelligent structures.

  1. Active current control in wind power plants during grid faults

    DEFF Research Database (Denmark)

    Martinez, Jorge; Kjær, Phillip C.; Rodriguez, Pedro

    2010-01-01

    , wind turbines usually have solutions that enable the turbines to control the generation of reactive power during faults. This paper addresses the importance of using an optimal injection of active current during faults in order to fulfil these grid codes. This is of relevant importance for severe......Modern wind power plants are required and designed to ride through faults in electrical networks, subject to fault clearing. Wind turbine fault current contribution is required from most countries with a high amount of wind power penetration. In order to comply with such grid code requirements...

  2. Rotor Current Control of DFIG for Improving Fault Ride - Through Using a Novel Sliding Mode Control Approach

    Science.gov (United States)

    Cai, Guowei; Liu, Cheng; Yang, Deyou

    2013-11-01

    The doubly fed induction generators (DFIG) have been recognized as the dominant technology used in wind power generation systems with the rapid development of wind power. However, continuous operation of DFIG may cause a serious wind turbine generators tripping accident, due to destructive over-current in the rotor winding which is caused by the power system fault or inefficient fault ride-through (FRT) strategy. A new rotor current control scheme in the rotor-side converter (RSC) ispresented to enhance FRT capacities of grid-connected DFIG. Due to the strongly nonlinear nature of DFIG and insensitive to DFIG parameter's variations, a novel sliding mode controller was designed. The controller combines extended state observer (ESO) with sliding model variable structure control theory. The simulation is carried out to verify the effectiveness of the proposed control approach under various types of grid disturbances. It is shown that the proposed controller provides enhanced transient features than the classic proportional-integral control. The proposed control method can effectively reduce over-current in the RSC, and the transient pulse value of electromagnetic torque is too large under power grid fault.

  3. Matching business-level strategic controls to strategy: Impact on control system effectiveness

    National Research Council Canada - National Science Library

    Fiegener, Mark K

    1994-01-01

    ... if they are to lead their organizations toward long-term strategic objectives. The contingent relationships between strategic control, business-level strategy, and the perceived effectiveness of the strategic control system are explored...

  4. Solution-based Chemical Strategies to Purposely Control the Microstructure of Functional Materials

    Institute of Scientific and Technical Information of China (English)

    Fei LIU; Congting SUN; Chenglin YAN; Dongfeng XUE

    2008-01-01

    Micro/nanostructured crystals with controlled architectures are desirable for many applications in optics, electronics, biology, medicine, and energy conversions. Low-temperature, aqueous chemical routes have been widely investigated for the synthesis of particles, and arrays of oriented nanorods and nanotubes. In this paper, based on the ideal crystal shapes predicted by the chemical bonding theory, we have developed some potential chemical strategies to tune the microstructure of functional materials, ZnS and Nb2O5 nanotube arrays, MgO wiskers and nestlike spheres, and cubic phase Cu2O microcrystals were synthesized here to elucidate these strategies. We describe their controlled crystallization processes and illustrate the detailed key factors controlling their growth by examining various reaction parameters. Current results demonstrate that our designed chemical strategies for tuning microstructure of functional materials are applicable to several technologically important materials, and therefore may be used as a versatile and effective route to the controllable synthesis of other inorganic functional materials.

  5. Control Systems Cyber Security:Defense in Depth Strategies

    Energy Technology Data Exchange (ETDEWEB)

    David Kuipers; Mark Fabro

    2006-05-01

    Information infrastructures across many public and private domains share several common attributes regarding IT deployments and data communications. This is particularly true in the control systems domain. A majority of the systems use robust architectures to enhance business and reduce costs by increasing the integration of external, business, and control system networks. However, multi-network integration strategies often lead to vulnerabilities that greatly reduce the security of an organization, and can expose mission-critical control systems to cyber threats. This document provides guidance and direction for developing ‘defense-in-depth’ strategies for organizations that use control system networks while maintaining a multi-tier information architecture that requires: Maintenance of various field devices, telemetry collection, and/or industrial-level process systems Access to facilities via remote data link or modem Public facing services for customer or corporate operations A robust business environment that requires connections among the control system domain, the external Internet, and other peer organizations.

  6. Control Systems Cyber Security:Defense in Depth Strategies

    Energy Technology Data Exchange (ETDEWEB)

    David Kuipers; Mark Fabro

    2006-05-01

    Information infrastructures across many public and private domains share several common attributes regarding IT deployments and data communications. This is particularly true in the control systems domain. A majority of the systems use robust architectures to enhance business and reduce costs by increasing the integration of external, business, and control system networks. However, multi-network integration strategies often lead to vulnerabilities that greatly reduce the security of an organization, and can expose mission-critical control systems to cyber threats. This document provides guidance and direction for developing ‘defense-in-depth’ strategies for organizations that use control system networks while maintaining a multi-tier information architecture that requires: Maintenance of various field devices, telemetry collection, and/or industrial-level process systems Access to facilities via remote data link or modem Public facing services for customer or corporate operations A robust business environment that requires connections among the control system domain, the external Internet, and other peer organizations.

  7. Improved Control Strategy for Subsynchronous Resonance Mitigation with Fractional-order PI Controller

    Science.gov (United States)

    Raju, D. Koteswara; Umre, Bhimrao S.; Junghare, A. S.; Chitti Babu, B.

    2016-12-01

    This paper explores a robust Fractional-order PI (FOPI) controller to diminish Subsynchronous Resonance (SSR) using Static Synchronous series compensator (SSSC). The diminution of SSR is accomplished by increasing the network damping with the injection of voltage of subsynchronous component into the line at those frequencies which are proximate to the torsional mode frequency of the turbine-generator shaft. The voltage of subsynchronous frequency component is extracted from the transmission line and further the similar quantity of series voltage is injected by SSSC into the line to make the current of subsynchronous frequency component to zero which is the major source of oscillations in the turbine-generator shaft. The insertion and fine tuning of Fractional-order PI controller in the control scheme of SSSC the subsynchronous oscillations are reduced to 4 % as compared to conventional PI controller. The studied system is modelled and simulated using MATLAB-Simulink and the results are analysed to show the precision and robustness of the proposed control strategy.

  8. Investigation and Comparison of Separate Meter-In Separate Meter-Out Control Strategies

    DEFF Research Database (Denmark)

    Pedersen, Henrik C.; Andersen, Torben Ole; Skoubo, Tobias

    2014-01-01

    . The possibility to independently control the meter-in and meter-out side not only increase the functionality of the system, but also opens up for better performance and/or lowered energy consumption. The focus of the current paper is therefore on investigation and comparison of what may be obtained using......, the control strategies are discussed and severalH¥ controllers are designed, for which both simulation and experimental results are presented. The controllers are evaluated with regard to performance and robustness and compared to a simple SISO control. Based on the findings, the possibilities and limitations...

  9. A current-mode buck DC-DC controller with adaptive on-time control

    Energy Technology Data Exchange (ETDEWEB)

    Li Yanming; Lai Xinquan; Ye Qiang; Yuan Bing; Chen Fuji [Institute of Electronic CAD, Xidian University, Xi' an 710071 (China); Jia Xinzhang, E-mail: ymli2004@126.co, E-mail: xqlai@mail.xidian.edu.c [Microelectronics Institute, Xidian University, Xi' an 710071 (China)

    2009-02-15

    A current-mode buck DC-DC controller based on adaptive on-time (AOT) control is presented. The on-time is obtained by the techniques of input feedforward and output feedback, and the adaptive control is achieved by a sample-hold and time-ahead circuit. The AOT current-mode control scheme not only obtains excellent transient response speed, but also achieves the independence of loop stability on output capacitor ESR. In addition, the AOT current-mode control does not have subharmonic oscillation phenomenon seen in fixed frequency peak current-mode control, so there is no need of the slope compensation circuit. The auto-skip pulse frequency modulation (PFM) mode improves the conversion efficiency of light load effectively. The controller has been fabricated with UMC 0.6-mum BCD process successfully and the detailed experimental results are shown.

  10. Myoelectric hand prosthesis force control through servo motor current feedback.

    Science.gov (United States)

    Sono, Tálita Saemi Payossim; Menegaldo, Luciano Luporini

    2009-10-01

    This paper presents the prehension force closed-loop control design of a mechanical finger commanded by electromyographic signal (EMG) from a patient's arm. The control scheme was implemented and tested in a mechanical finger prototype with three degrees of freedom and one actuator, driven by arm muscles EMG of normal volunteers. Real-time indirect estimation of prehension force was assessed by measuring the DC servo motor actuator current. A model of the plant comprising finger, motor, and grasped object was proposed. Model parameters were identified experimentally and a classical feedback phase-lead compensator was designed. The controlled mechanical finger was able to provide a more accurate prehension force modulation of a compliant object when compared to open-loop control.

  11. A Simple Control Strategy Using Speedy Transient Response for Multiphase Buck Converter

    Science.gov (United States)

    Sasikala, K.; Ravikumar, D.; Rubini, B.

    2017-03-01

    The high performance of recent originating digital processors requires power supply for transient output, firm voltage regulation and high current. Industry has taken up interleaved multiphase synchronous buck converters for meeting such demands. Application of the voltage mode (ripple) hysteretic strategy to multiphase Voltage Regulator Units (VRU) would help satisfying many of the upcoming digital processors and IC’s powering demands. This arises from the use of the various advantages that can be obtained from this technique. This current division method is known for several benefits it provides: easy accessibility in application to all control methods, with freedom from the prime control technique in voltage regulation loop, absence of any necessity for current reference, better accuracy in current division of equal magnitude at almost every load conditions in standstill and transients. As against this, there are several challenges that involve distribution of multiple control signals, current sharing and sensitivity to noise, high speed comparators, hysteretic band accuracy and stable at large load transients. In addition, application of the current division technique presented was made to a multiphase voltage mode ripple controlled Buck Converter that produced a novel and easy control strategy having minimum output voltage ripples and speedy transient output.

  12. Study on Control Strategies for the Multilevel Cascaded Converters

    Directory of Open Access Journals (Sweden)

    Lin Xu

    2013-11-01

    Full Text Available The multilevel cascaded converters are extensively applied for high-voltage and high-power applications, which are considered as the most favorable topologies for the high power ac-drives and the high-voltage DC transmission (HVDC systems using the voltage source converters (VSCs. This paper presents the dc capacitor balancing and effective current regulation methodologies for the multilevel cascaded converters. The dc-link voltage balancing and capacitor energy evolving mechanism of the MMCC is analyzed, and an effective control scheme is devised by utilizing two dc capacitor voltage control loops, including the total capacitor voltage controller (TCVC, the capacitor voltage balancing controller (CVBC. The predictive current controller is proposed to enhance the tracking accuracy of current control loop. The proportional-resonant controller (PRC is used as circulating current damping controller of the modular multilevel converter, which is found to be highly effective to minimize the circulating current. The Electromagnetic Transient Program (EMTP is utilized for digital simulation of the single-phase five-level modular multilevel converter. The effectiveness of the control scheme is validated by the simulation results.

  13. Electric Machine with Boosted Inductance to Stabilize Current Control

    Science.gov (United States)

    Abel, Steve

    2013-01-01

    High-powered motors typically have very low resistance and inductance (R and L) in their windings. This makes the pulse-width modulated (PWM) control of the current very difficult, especially when the bus voltage (V) is high. These R and L values are dictated by the motor size, torque (Kt), and back-emf (Kb) constants. These constants are in turn set by the voltage and the actuation torque-speed requirements. This problem is often addressed by placing inductive chokes within the controller. This approach is undesirable in that space is taken and heat is added to the controller. By keeping the same motor frame, reducing the wire size, and placing a correspondingly larger number of turns in each slot, the resistance, inductance, torque constant, and back-emf constant are all increased. The increased inductance aids the current control but ruins the Kt and Kb selections. If, however, a fraction of the turns is moved from their "correct slot" to an "incorrect slot," the increased R and L values are retained, but the Kt and Kb values are restored to the desired values. This approach assumes that increased resistance is acceptable to a degree. In effect, the heat allocated to the added inductance has been moved from the controller to the motor body, which in some cases is preferred.

  14. Analysis of Control Strategies for Aircraft Flight Upset Recovery

    Science.gov (United States)

    Crespo, Luis G.; Kenny, Sean P.; Cox, David E.; Muri, Daniel G.

    2012-01-01

    This paper proposes a framework for studying the ability of a control strategy, consisting of a control law and a command law, to recover an aircraft from ight conditions that may extend beyond the normal ight envelope. This study was carried out (i) by evaluating time responses of particular ight upsets, (ii) by evaluating local stability over an equilibrium manifold that included stall, and (iii) by bounding the set in the state space from where the vehicle can be safely own to wings-level ight. These states comprise what will be called the safely recoverable ight envelope (SRFE), which is a set containing the aircraft states from where a control strategy can safely stabilize the aircraft. By safe recovery it is implied that the tran- sient response stays between prescribed limits before converging to a steady horizontal ight. The calculation of the SRFE bounds yields the worst-case initial state corresponding to each control strategy. This information is used to compare alternative recovery strategies, determine their strengths and limitations, and identify the most e ective strategy. In regard to the control law, the authors developed feedback feedforward laws based on the gain scheduling of multivariable controllers. In regard to the command law, which is the mechanism governing the exogenous signals driving the feed- forward component of the controller, we developed laws with a feedback structure that combines local stability and transient response considera- tions. The upset recovery of the Generic Transport Model, a sub-scale twin-engine jet vehicle developed by NASA Langley Research Center, is used as a case study.

  15. Simple Augmented Current Controller with OHC Technique for grid current compensation in the Distribution System

    Directory of Open Access Journals (Sweden)

    S. Rajalingam

    2014-05-01

    Full Text Available This paper presents a novel control technique on four leg inverter with which the distribution grid is interconnected with the domestic houses. Most of the houses in the distribution side possess inverter for the usage of Electricity. With the advancement in Solar & wind, it will become easy to see houses, often with solar & a small Wind power system. The excess power generated can be exchanged with the Electricity Board for providing uninterruptible power supply. During this exchange there may be a deterioration in the quality of power, most often the grid current gets affected with a large harmonic distortion, and also there exists unbalanced grid currents. Thus, it is necessary to provide uninterruptible power supply with good quality of power. In spite of several controllers, the proposed augmented controller has its own reliability & quick response with Overall Harmonic Compensation (OHC technique which relies on DSP based filter. This Augmented based control technique with OHC is demonstrated extensively with MATLAB/Simulink simulation.

  16. Current Situation of International Nuclear Arms Control and Nuclear Disarmament

    Institute of Scientific and Technical Information of China (English)

    Gong; Xianfu

    2014-01-01

    <正>Currently,international nuclear arms control and nuclear disarmament process is showing both encouraging and frustrating signs,with a stress on the latter.The following is a general picture:First,the new U.S.-Russian nuclear disarmament process faces challenges and prospect of a new round of nuclear disarmament negotiation is grim.As a result of implementing the New START signed in February 2011,as of March 1,2014,the United States has 1585

  17. A new cascaded control strategy for paralleled line-interactive UPS with LCL filter

    Science.gov (United States)

    Zhang, X. Y.; Zhang, X. H.; Li, L.; Luo, F.; Zhang, Y. S.

    2016-08-01

    Traditional uninterrupted power supply (UPS) is difficult to meet the output voltage quality and grid-side power quality requirements at the same time, and usually has some disadvantage, such as multi-stage conversion, complex structure, or harmonic current pollution to the utility grid and so on. A three-phase three-level paralleled line-interactive UPS with LCL filter is presented in this paper. It can achieve the output voltage quality and grid-side power quality control simultaneously with only single-conversion power stage, but the multi-objective control strategy design is difficult. Based on the detailed analysis of the circuit structure and operation mechanism, a new cascaded control strategy for the power, voltage, and current is proposed. An outer current control loop based on the resonant control theory is designed to ensure the grid-side power quality. An inner voltage control loop based on the capacitance voltage and capacitance current feedback is designed to ensure the output voltage quality and avoid the resonance peak of the LCL filter. Improved repetitive controller is added to reduce the distortion of the output voltage. The setting of the controller parameters is detailed discussed. A 100kVA UPS prototype is built and experiments under the unbalanced resistive load and nonlinear load are carried out. Theoretical analysis and experimental results show the effectiveness of the control strategy. The paralleled line-interactive UPS can not only remain constant three-phase balanced output voltage, but also has the comprehensive power quality management functions with three-phase balanced grid active power input, low THD of output voltage and grid current, and reactive power compensation. The UPS is a green friendly load to the utility.

  18. An Efficient Modal Control Strategy for the Active Vibration Control of a Truss Structure

    Directory of Open Access Journals (Sweden)

    Ricardo Carvalhal

    2007-01-01

    Full Text Available In this paper an efficient modal control strategy is described for the active vibration control of a truss structure. In this approach, a feedback force is applied to each mode to be controlled according to a weighting factor that is determined by assessing how much each mode is excited by the primary source. The strategy is effective provided that the primary source is at a fixed position on the structure, and that the source is stationary in the statistical sense. To test the effectiveness of the control strategy it is compared with an alternative, established approach namely, Independent Modal Space Control (IMSC. Numerical simulations show that with the new strategy it is possible to significantly reduce the control effort required, with a minimal reduction in control performance.

  19. Active control strategy on a catenary-pantograph validated model

    Science.gov (United States)

    Sanchez-Rebollo, C.; Jimenez-Octavio, J. R.; Carnicero, A.

    2013-04-01

    Dynamic simulation methods have become essential in the design process and control of the catenary-pantograph system, overall since high-speed trains and interoperability criteria are getting very trendy. This paper presents an original hardware-in-the-loop (HIL) strategy aimed at integrating a multicriteria active control within the catenary-pantograph dynamic interaction. The relevance of HIL control systems applied in the frame of the pantograph is undoubtedly increasing due to the recent and more demanding requirements for high-speed railway systems. Since the loss of contact between the catenary and the pantograph leads to arcing and electrical wear, and too high contact forces cause mechanical wear of both the catenary wires and the strips of the pantograph, not only prescribed but also economic and performance criteria ratify such a relevance. Different configurations of the proportional-integral-derivative (PID) controller are proposed and applied to two different plant systems. Since this paper is mainly focused on the control strategy, both plant systems are simulation models though the methodology is suitable for a laboratory bench. The strategy of control involves a multicriteria optimisation of the contact force and the consumption of the energy supplied by the control force, a genetic algorithm has been applied for this purpose. Thus, the PID controller is fitted according to these conflicting objectives and tested within a nonlinear lumped model and a nonlinear finite element model, being the last one validated against the European Standard EN 50318. Finally, certain tests have been accomplished in order to analyse the robustness of the control strategy. Particularly, the relevance or the plant simulation, the running speed and the instrumentation time delay are studied in this paper.

  20. Temperature control strategy for a seal fatigue tester

    Directory of Open Access Journals (Sweden)

    M. Związek

    2008-08-01

    Full Text Available Purpose: The aim of the paper is optimization of a control strategy used in a seal fatigue tester.Design/methodology/approach: Analytical approach has been applied to get an understanding of a heat exchange process. It is required to optimize the control process algorithm.Findings: The initial control algorithm has been improved regarding numerous tests under different operating conditions. The final version of the control program allows to maintain the temperature according to the on-off strategy minimizing the temperature oscillations and potential overshoots.Research limitations/implications: It should be considered a new control strategy based on PID controller.Practical implications: The major component of the tester is the heat exchanger. It consists of a tube and embedded pipe circuit feeding with the external heating or cooling medium. The tube is a cylindrical housing where the seals are assembled at both sides. Two main pumps circulate the medium at a specified flow rate and pressure. The temperature is maintained to hold it almost constant during heating and cooling phases. Two thermocouples are placed close to the seals, and the one in the middle of the heat exchanger tube. The tester is equipped with a control system consisting of a PLC controller and LabView data acquisition application. It is possible to control the device remotely through LAN/WAN networks. The LabView application communicates with the controller via software with the use of PPI (Point-To-Point Interface protocol. A new control algorithm has allowed to perform tests according to testing specification without significant overshoots.Originality/value: On-off control algorithm has been proposed for a combined heating-cooling installation rarely using in the industrial solutions.

  1. Enhancing the Frequency Adaptability of Periodic Current Controllers with a Fixed Sampling Rate for Grid-Connected Power Converters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

    2016-01-01

    the instantaneous grid information (e.g., frequency and phase of the grid voltage) for the current control, which is commonly performed by a Phase-Locked-Loop (PLL) system. Hence, harmonics and deviations in the estimated frequency by the PLL could lead to current tracking performance degradation, especially...... for the periodic signal controllers (e.g., PR and RC) with a fixed sampling rate. In this paper, the impacts of frequency deviations induced by the PLL and/or the grid disturbances on the selected current controllers are investigated by analyzing the frequency adaptability of these current controllers....... Subsequently, strategies to enhance the frequency adaptability of the current controllers are proposed for the power converters to produce high quality feed-in currents even in the presence of grid frequency deviations. Specifically, by feeding back the PLL estimated frequency to update the center frequencies...

  2. Control strategies used in the control software for the Heavy Ion Research Facility in Lanzhou

    Science.gov (United States)

    Zhou, Wen-Xiong; Wang, Yan-Yu; Pan, Liang-Ming; Tu, Sheng-Pan

    2016-07-01

    Automation control systems are important for the operation of an accelerator. To ensure the reliable, stable and flexible operation of the Heavy Ion Research Facility in Lanzhou (HIRFL), several control systems are developed. The developed control systems are the SECRAL control system, the LECR3 control system, the LAPECR1 control system and the Electro-Static septum control system. The corresponding control software systems are developed using Visual C++. To ensure the accuracy, stability and flexibility of the control systems, some special control strategies are developed in the control software systems. This paper provides a detailed description of the main control strategies used in the control software systems. The main control strategies are composed of a reliable communication mechanism, a correct data/command transmission mechanism, an efficient data storage mechanism and an interlock protection mechanism. To guarantee a reliable communication between the devices for the commercially purchased devices and the built in-house ones, a modified heartbeat method is developed. To provide flexible reconstitution function for the control systems, the command queue and the state machine are combined. The message mechanism and the multiple windows mechanism are also used for the module mechanism. The relevant control systems are introduced as examples of these control strategies. These systems have been running stably for several years.

  3. Chaos Control on a Duopoly Game with Homogeneous Strategy

    Directory of Open Access Journals (Sweden)

    Manying Bai

    2016-01-01

    Full Text Available We study the dynamics of a nonlinear discrete-time duopoly game, where the players have homogenous knowledge on the market demand and decide their outputs based on adaptive expectation. The Nash equilibrium and its local stability are investigated. The numerical simulation results show that the model may exhibit chaotic phenomena. Quasiperiodicity is also found by setting the parameters at specific values. The system can be stabilized to a stable state by using delayed feedback control method. The discussion of control strategy shows that the effect of both firms taking control method is better than that of single firm taking control method.

  4. Development of Low-Cost Current Controlled Stimulator for Paraplegics

    Directory of Open Access Journals (Sweden)

    Aizan Masdar

    2012-12-01

    Full Text Available A spinal cord injury (SCI has a severe impact on human life in general as well as on the physical status and condition. The use of electrical signals to restore the function of paralyzed muscles is called functional electrical stimulation (FES. FES is a promising way to restore mobility to SCI by applying low-level electrical current to the paralyzed muscles so as to enhance that person’s ability to function and live independently. However, due to the limited number of commercially available FES assisted exerciser systems and their rather high cost, the conventional devices are unaffordable for most peoples. It is also inconvenient because of wired based system that creates a limitation in performing exercise. Thus, this project is concerned with the development of low-cost current controlled stimulator mainly for the paraplegic subjects. The developed device is based on a microcontroller, wireless based system using Zigbee module, voltage-to-current converter circuit and should produce proper monopolar and bipolar current pulses, pulse trains, arbitrary current waveforms, and a trigger output for FES applications. This device has been developed as in the new technique of the stimulator development with low cost and one of the contributing factors in Rehabilitation Engineering for patients with SCI.

  5. Optimized Control Strategy For Over Loaded Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Knudsen, Torben; Wisniewski, Rafal

    2015-01-01

    Abstract Optimized control strategy for overloaded offshore wind turbines Introduction Operation and maintenance cost are an important part of cost of energy especially for offshore wind farms. Typically unplanned service is called for due to detection off excessive loads on components, e...... controller tuning for a given wind turbine. It also enables a very safe and robust comparison between a new control strategy and the present one. Main body of abstract Is it true that power de-rating indeed the best way to reduce loads? The power de-rating approach has the drawback of only indirectly...... and service at offshore location, where accessibility can be problematic. The controller objectives are focused directly on the actual objective like lowering of fore aft fatigue loads, instead of using an indirect objective of de-rating the power production of the wind turbine. This means what the wind...

  6. Comparison of Power Control Strategies for DFIG Wind Turbines

    DEFF Research Database (Denmark)

    Teodorescu, Remus; Luna, A.; Rodríguez, P.

    2008-01-01

    The classical control techniques for regulating the active and reactive power delivery in doubly fed induction generators (DFIG), for wind power applications, are normally based on voltage oriented control (VOC) strategies. Among these algorithms, those that work in a synchronous reference frame...... VOC strategy able to control the operation of a DFIG in the αβ reference frame, with no need of flux position estimation, something that conducts to a more simple and robust algorithm. In order to evaluate the advantages of this new control proposal, namely VOC-RRF, their performance will be compared......, attached to the magnetic flux vector, became very popular. In spite of the good behaviour of such algorithms their performance depends highly on an accurate detection of the stator flux position, something that can be critical under unbalanced or distorted grid voltage conditions. This paper presents a new...

  7. Control Strategies for DFIG Wind Turbines Under Grid Fault

    DEFF Research Database (Denmark)

    Luna, Alvara; Rolan, A.; Medeiros, G.

    2009-01-01

    The classical control techniques for regulating the active and reactive power delivery in doubly fed induction generators (DFIG), for wind power applications, are normally based on voltage oriented control (VOC) strategies. Among these algorithms, those that work in a synchronous reference frame...... VOC strategy able to control the operation of a DFIG in the αβ reference frame, with no need of flux position estimation, something that conducts to a more simple and robust algorithm. In order to evaluate the advantages of this new control proposal, namely VOC-RRF, their performance will be compared......, attached to the magnetic flux vector, became very popular. In spite of the good behaviour of such algorithms their performance depends highly on an accurate detection of the stator flux position, something that can be critical under unbalanced or distorted grid voltage conditions. This paper presents a new...

  8. Effective variable switching point predictive current control for ac low-voltage drives

    Science.gov (United States)

    Stolze, Peter; Karamanakos, Petros; Kennel, Ralph; Manias, Stefanos; Endisch, Christian

    2015-07-01

    This paper presents an effective model predictive current control scheme for induction machines driven by a three-level neutral point clamped inverter, called variable switching point predictive current control. Despite the fact that direct, enumeration-based model predictive control (MPC) strategies are very popular in the field of power electronics due to their numerous advantages such as design simplicity and straightforward implementation procedure, they carry two major drawbacks. These are the increased computational effort and the high ripples on the controlled variables, resulting in a limited applicability of such methods. The high ripples occur because in direct MPC algorithms the actuating variable can only be changed at the beginning of a sampling interval. A possible remedy for this would be to change the applied control input within the sampling interval, and thus to apply it for a shorter time than one sample. However, since such a solution would lead to an additional overhead which is crucial especially for multilevel inverters, a heuristic preselection of the optimal control action is adopted to keep the computational complexity at bay. Experimental results are provided to verify the potential advantages of the proposed strategy.

  9. Strategies of bringing drug product marketing applications to meet current regulatory standards.

    Science.gov (United States)

    Wu, Yan; Freed, Anita; Lavrich, David; Raghavachari, Ramesh; Huynh-Ba, Kim; Shah, Ketan; Alasandro, Mark

    2015-08-01

    In the past decade, many guidance documents have been issued through collaboration of global organizations and regulatory authorities. Most of these are applicable to new products, but there is a risk that currently marketed products will not meet the new compliance standards during audits and inspections while companies continue to make changes through the product life cycle for continuous improvement or market demands. This discussion presents different strategies to bringing drug product marketing applications to meet current and emerging standards. It also discusses stability and method designs to meet process validation and global development efforts.

  10. Dynamics and stabilization of peak current-mode controlled buck converter with constant current load

    Science.gov (United States)

    Leng, Min-Rui; Zhou, Guo-Hua; Zhang, Kai-Tun; Li, Zhen-Hua

    2015-10-01

    The discrete iterative map model of peak current-mode controlled buck converter with constant current load (CCL), containing the output voltage feedback and ramp compensation, is established in this paper. Based on this model the complex dynamics of this converter is investigated by analyzing bifurcation diagrams and the Lyapunov exponent spectrum. The effects of ramp compensation and output voltage feedback on the stability of the converter are investigated. Experimental results verify the simulation and theoretical analysis. The stability boundary and chaos boundary are obtained under the theoretical conditions of period-doubling bifurcation and border collision. It is found that there are four operation regions in the peak current-mode controlled buck converter with CCL due to period-doubling bifurcation and border-collision bifurcation. Research results indicate that ramp compensation can extend the stable operation range and transfer the operating mode, and output voltage feedback can eventually eliminate the coexisting fast-slow scale instability. Project supported by the National Natural Science Foundation of China (Grant No. 61371033), the Fok Ying-Tung Education Foundation for Young Teachers in the Higher Education Institutions of China (Grant No. 142027), the Sichuan Provincial Youth Science and Technology Fund, China (Grant Nos. 2014JQ0015 and 2013JQ0033), and the Fundamental Research Funds for the Central Universities, China (Grant No. SWJTU11CX029).

  11. Current Status and Prevention Strategy for Coal-arsenic Poisoning in Guizhou, China

    OpenAIRE

    Li, Dasheng; An, Dong; Zhou, Yunsu; Liu, Jie; Waalkes, Michael P.

    2006-01-01

    Arsenic exposure from burning coal with high arsenic contents occurs in southwest Guizhou, China. Coal in this region contains extremely high concentrations of inorganic arsenic. Arsenic exposure from coal-burning is much higher than exposure from arsenic-contaminated water in other areas of China. The current status and prevention strategies for arsenic poisoning from burning high-arsenic coal in southwest Guizhou, China, is reported here. Over 3,000 arsenic-intoxicated patients were diagnos...

  12. Current situation of Chinese forestry tactics and strategy of sustainable development

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on the analysis of the current situation of Chinese forestry and aseries of ecological, environmental, economic, and social problems, this paper emphasized on the importance of forests in social and economic development in China The author pointed out that sustainable development, particularly the sustainable development of forestry, is the inevitable choice to solve the problems of ecological environment and social economics. The objectives, criteria, and strategies of sustaining forestry were also demonstrated and expounded, from the viewpoints of ecology, economics, and sociology.

  13. Current Status and Future Strategies for Development of Transgenic Plants in China

    Institute of Scientific and Technical Information of China (English)

    De-Ping Wang

    2007-01-01

    In this review, the author summarized the current status, challenges, and strategies in China in the development of transgenic plants and its commercialization. Based on sets of successful examples and data achieved from execution of the National Special Project for Transgenic Plant Research and Commercialization in the last five years, the priorities and key directions were put forward for the future development of transgenic plants in China.

  14. Back to basics: The current competitive strategy of HSBC Bank Canada

    OpenAIRE

    Sheppard, Christopher Patrick

    2007-01-01

    This paper analyzes HSBC Bank Canada’s current strategy for competing within the Canadian banking industry. HSBC Bank Canada has enjoyed considerable financial success over the past couple of decades. However, the overall direction of the industry is towards lower, interest-rate spreads and intensified competition. Many of the bank’s primary competitors are reducing costs through a variety of means, such as centralization and automation of processes. In order for HSBC Bank Canada to succeed i...

  15. Co-ordinated Control Strategy for Hybrid Wind Farms with PMSG and FSIG under Unbalanced Grid Voltage Condition

    DEFF Research Database (Denmark)

    Zeng, Xin; Yao, Jun; Chen, Zhiqian

    2016-01-01

    This paper investigates a control strategy for a wind farm with the direct-driven permanent-magnet synchronous generators (PMSG)-based wind turbines and the fixed speed induction generators (FSIG)-based wind turbines under unbalanced grid voltage condition. By controlling the PMSG-based wind farm...... of the negative-sequence current provided by the PMSG-based wind farm under different average active power output and different VUF conditions is deduced, and the impacts of its phase angle on the VUF mitigation control effect are further studied. The improved control strategy of injecting negative......-sequence current from the PMSG-based wind farm by the modified negative-sequence voltage and current double closed-loop control system is then developed. Finally, the correctness of theoretical analysis and the effectiveness of the proposed control strategy are validated by the experimental results....

  16. Mothers' Teaching Strategies and Children's Effortful Control: A Longitudinal Study

    Science.gov (United States)

    Eisenberg, Nancy; Vidmar, Masa; Spinrad, Tracy L.; Eggum, Natalie D.; Edwards, Alison; Gaertner, Bridget; Kupfer, Anne

    2010-01-01

    Findings on the relation of maternal verbal teaching strategies to children's effortful control (EC; i.e., self-regulation) are limited in quantity and somewhat inconsistent. In this study, children's EC was assessed at 18, 30, and 42 months (ns = 255, 229, and 209, respectively) with adults' reports and a behavioral measure. Mothers' verbal…

  17. 40 CFR 52.282 - Control strategy and regulations: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy and regulations: Ozone... and regulations: Ozone. (a) Attainment determination. EPA has determined that the Ventura County severe 1-hour ozone nonattainment area attained the 1-hour ozone NAAQS by the applicable attainment...

  18. 40 CFR 52.1683 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.1683...: Ozone. (a) The State of New York has certified to the satisfaction of the EPA that no sources are... Polystyrene Resins. (b)-(e) (f) Attainment Determination. (1) EPA is determining that the 1-hour...

  19. 40 CFR 52.977 - Control strategy and regulations: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy and regulations: Ozone... and regulations: Ozone. Determination of Attainment. Effective March 12, 2010 EPA has determined the Baton Rouge 1-hour ozone nonattainment area has attained the 1-hour ozone National Ambient Air...

  20. 40 CFR 52.1023 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.1023...: Ozone. (a) Determination. EPA is determining that, as of July 21, 1995, the Lewiston-Auburn ozone nonattainment area has attained the ozone standard and that the reasonable further progress and...

  1. 40 CFR 52.1885 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.1885...: Ozone. (a) Part D—Approval. The following portions of the Ohio plan are approved: (1) The ozone portions...: Akron, Canton, Cincinnati, Cleveland, Columbus, Dayton, Toledo and Youngstown. (4) The...

  2. 40 CFR 52.1982 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.1982 Section 52.1982 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...: Ozone. (a) Part D—Approval. (1) The Salem/ Portland and Medford/Ashland area attainment plans...

  3. 40 CFR 52.2332 - Control Strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control Strategy: Ozone. 52.2332...: Ozone. Determinations—EPA is determining that, as of July 18, 1995, the Salt Lake and Davis Counties ozone nonattainment area has attained the ozone standard based on air quality monitoring data from...

  4. 40 CFR 52.1174 - Control strategy: Ozone.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.1174...: Ozone. (a) Part D—Conditional Approval—Michigan Rules 336.1603 and 336.1606 are approved provided that... Resources submitted a revision to the ozone State Implementation Plan (SIP) for the 1990 base year...

  5. Control strategies for brushless doubly fed reluctance machines

    OpenAIRE

    Jovanovic, Milutin; Betz, Robert

    2001-01-01

    Paper presents the development and results of comprehensive comparative analysis of different vector control strategies for performance optimisation of the BDFRM being considered as a viable cost-effective brushless alternative to traditional brush and less reliable solutions in applications with limited variable speed ranges (such as wind turbines). Australian Research Council and EPSRC projects.

  6. Mothers' Teaching Strategies and Children's Effortful Control: A Longitudinal Study

    Science.gov (United States)

    Eisenberg, Nancy; Vidmar, Masa; Spinrad, Tracy L.; Eggum, Natalie D.; Edwards, Alison; Gaertner, Bridget; Kupfer, Anne

    2010-01-01

    Findings on the relation of maternal verbal teaching strategies to children's effortful control (EC; i.e., self-regulation) are limited in quantity and somewhat inconsistent. In this study, children's EC was assessed at 18, 30, and 42 months (ns = 255, 229, and 209, respectively) with adults' reports and a behavioral measure. Mothers' verbal…

  7. 40 CFR 52.1680 - Control strategy: Monitoring and reporting.

    Science.gov (United States)

    2010-07-01

    ... Control strategy: Monitoring and reporting. (a) Section 227.6 (a) and (f) are disapproved because they are not consistent with the continuous monitoring and reporting requirements of 40 CFR 51.214. ... reporting. 52.1680 Section 52.1680 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR...

  8. RIVM Centre for Infectious Disease Control : Strategy 2016-2021

    NARCIS (Netherlands)

    Riesmeijer RM; van Dissel JT; I&V

    2017-01-01

    This strategy describes the ambitions of the Centre for Infectious Disease Control (CIb) for the coming years. It concerns the changes that the CIb considers to be necessary, rather than a summary of activities.

    Thanks to the efforts made by prevention and vaccination programmes, in the

  9. Research on Improved Control Strategy for STATCOM Based on Virtual Matrix Method

    Directory of Open Access Journals (Sweden)

    Wang Xudong

    2016-01-01

    Full Text Available Fast and accurate detection of reactive current is the precondition for the realization of static synchronous compensator (STATCOM reactive power compensation and harmonic suppression. Aiming at deviation and delay of the traditional reactive current detection algorithm with phase-locked loop (PLL and low-pass filter (LPF of STATCOM, a novel improved reactive current detection algorithm without PLL is proposed, in which the virtual matrix (VM is built to replace the original PLL, and improved current average value filter is used to realize the function of LPF, so as to improve the real-time performance and robustness of reactive current detection. The realization process of VM detection method is derived in this paper, and improved control strategy for STATCOM is designed based on the VM detection method. Simulation analysis of the proposed detection algorithm and control strategy is conducted in Matlab platform so as to verify the correctness and effectiveness of the control strategy. The VM detection has the advantages of simple structure, fast response and easy for digital realization, which provides reference for the improvement of reactive power compensation precision for STATCOM.

  10. Emerging trends in vibration control of wind turbines: a focus on a dual control strategy.

    Science.gov (United States)

    Staino, Andrea; Basu, Biswajit

    2015-02-28

    The paper discusses some of the recent developments in vibration control strategies for wind turbines, and in this context proposes a new dual control strategy based on the combination and modification of two recently proposed control schemes. Emerging trends in the vibration control of both onshore and offshore wind turbines are presented. Passive, active and semi-active structural vibration control algorithms have been reviewed. Of the existing controllers, two control schemes, active pitch control and active tendon control, have been discussed in detail. The proposed new control scheme is a merger of active tendon control with passive pitch control, and is designed using a Pareto-optimal problem formulation. This combination of controllers is the cornerstone of a dual strategy with the feature of decoupling vibration control from optimal power control as one of its main advantages, in addition to reducing the burden on the pitch demand. This dual control strategy will bring in major benefits to the design of modern wind turbines and is expected to play a significant role in the advancement of offshore wind turbine technologies. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  11. Robust antisynchronization of chaos using sliding mode control strategy

    Indian Academy of Sciences (India)

    Amit Mondal; Mitul Islam; Nurul Islam

    2015-01-01

    The paper proposes a sliding mode control strategy-based scheme for achieving anti-synchronization between two coupled non-linear chaotic systems. The method works irrespective of whether the systems under consideration possess or lack inverse symmetry. Using a linear sliding surface, a sliding mode control input and a non-linear coupling function are designed that synchronizes the systems antiphase. Finite-time convergence of the method is established. The controller is also robust to all forms of bounded perturbations and this robustness can be easily achieved by tuning of a single controller parameter and introduction of a control vector. The controller is also made chattering-free by producing a continuous analogue of the discontinuous control input. The effectiveness of the method is established by implementing it to antisynchronize chaotic Sprott systems and Rossler systems. The results are also verified through numerical simulation work.

  12. Balancing Control Strategy for Li-Ion Batteries String Based on Dynamic Balanced Point

    Directory of Open Access Journals (Sweden)

    Dong-Hua Zhang

    2015-03-01

    Full Text Available The Li-ion battery is becoming the optimal choice for the Electric Vehicle’s (EV power supply. In order to protect the Li-ion battery from charging damage and to prolong the battery’s life, a special control strategy based on the dynamic balanced point along with a non-dissipative equalizer is presented. The main focus of the proposed control strategy is to insure that the individual cell of a battery pack will be rapidly, efficiently and simultaneously balanced, by adjusting equalizing current of each cell dynamically. In this paper, a model of a four series connected Li-ion batteries pack has been established to evaluate the proposed control strategy. Superior performance is demonstrated by the simulation and experiment.

  13. High-Speed Current dq PI Controller for Vector Controlled PMSM Drive

    Directory of Open Access Journals (Sweden)

    Mohammad Marufuzzaman

    2014-01-01

    Full Text Available High-speed current controller for vector controlled permanent magnet synchronous motor (PMSM is presented. The controller is developed based on modular design for faster calculation and uses fixed-point proportional-integral (PI method for improved accuracy. Current dq controller is usually implemented in digital signal processor (DSP based computer. However, DSP based solutions are reaching their physical limits, which are few microseconds. Besides, digital solutions suffer from high implementation cost. In this research, the overall controller is realizing in field programmable gate array (FPGA. FPGA implementation of the overall controlling algorithm will certainly trim down the execution time significantly to guarantee the steadiness of the motor. Agilent 16821A Logic Analyzer is employed to validate the result of the implemented design in FPGA. Experimental results indicate that the proposed current dq PI controller needs only 50 ns of execution time in 40 MHz clock, which is the lowest computational cycle for the era.

  14. Current-Loop Control for the Pitching Axis of Aerial Cameras via an Improved ADRC

    Directory of Open Access Journals (Sweden)

    BingYou Liu

    2017-01-01

    Full Text Available An improved active disturbance rejection controller (ADRC is designed to eliminate the influences of the current-loop for the pitching axis control system of an aerial camera. The improved ADRC is composed of a tracking differentiator (TD, an improved extended state observer (ESO, an improved nonlinear state error feedback (NLSEF, and a disturbance compensation device (DCD. The TD is used to arrange transient process. The improved ESO is utilized to observe the state extended by nonlinear dynamics, model uncertainty, and external disturbances. Overtime variation of the current-loop can be predicted by the improved ESO. The improved NLSEF is adopted to restrain the residual errors of the current-loop. The DCD is used to compensate the overtime variation of the current-loop in real time. The improved ADRC is designed based on a new nonlinear function newfal(·. This function exhibits enhanced continuity and smoothness compared to previously available nonlinear functions. Thus, the new nonlinear function can effectively decrease the high-frequency flutter phenomenon. The improved ADRC exhibits improved control performance, and disturbances of the current-loop can be eliminated by the improved ADRC. Finally, simulation experiments are performed. Results show that the improved ADRC displayed better performance than the proportional integral (PI control strategy and traditional ADRC.

  15. Simulation and experimental results of hybrid electric machine with a novel flux control strategy

    Directory of Open Access Journals (Sweden)

    Paplicki Piotr

    2015-03-01

    Full Text Available The paper presents selected simulation and experimental results of a hybrid ECPMS-machine (Electric Controlled Permanent Magnet Synchronous Machine. This permanent magnets (PMs excited machine offers an extended magnetic field control capability which makes it suitable for battery electric vehicle (BEV drives. Rotor, stator and the additional direct current control coil of the machine are analyzed in detail. The control system and strategy, the diagram of power supply system and an equivalent circuit model of the ECPMS-machine are presented. Influence of the additional excitation on the performance parameters of the machine, such as: torque, efficiency, speed limits and back-EMF have also been discussed.

  16. Combined variable speed/variable pitch controlled 3-bladed wind turbine: Control strategies; Dobbelt styrbar 3-bladet vindmoelle: Reguleringsstrategier

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, A.; Bindner, H.

    1998-12-01

    This report is a part of the project `Combined variable speed/variable pitch controlled 3-bladed wind turbine`. The purpose of the project is to investigate a variable speed/variable pitch controlled wind turbine. The total reporting work of the projects is divided in 2 reports: Control Strategies (R-1071) (the current report); Comparison between pitch controlled wind turbine and pitch controlled wind turbine with variable speed (R-1072). The current report presents two control strategies, which can be used in a variable speed/variable pitch wind turbine. These control strategies are investigated regarding power production, structural loads and power quality. A static model is developed in order to establish the control strategy and a dynamic model is used to analyse the loads and the performance of the control. First the reports presents the background/motivation for combining variable speed with variable pitch wind turbine, after which an investigation of the power production for different control strategies it presented. The report further contains a nonlinear simulation model for a wind turbine, including control systems and frequency converter. The model, developed for control purposes, includes a model for tower and flapwise blade bending, a model for the pitch system, nonlinear aerodynamic, frequency converter, turbulens and drive train. The model is validated through comparisons with measurements performed on a test facility, which consists of a Vestas V27-225 kW wind turbine with a SAMI-STAR 400 kVA frequency converter from ABB. The model is used both to establish the parameters of the controller and afterwards to investigate the performance of a variable speed wind turbine. In report R-1072 a comparison between pitch controlled wind turbine and pitch controlled wind turbine with variable speed is presented based on measurements from the test facility. The project participants were Vestas Wind Systems A/S, ABB Energy and Industry A/S and Risoe National

  17. Precision electronic speed controller for an alternating-current motor

    Science.gov (United States)

    Bolie, V.W.

    A high precision controller for an alternating-current multi-phase electrical motor that is subject to a large inertial load. The controller was developed for controlling, in a neutron chopper system, a heavy spinning rotor that must be rotated in phase-locked synchronism with a reference pulse train that is representative of an ac power supply signal having a meandering line frequency. The controller includes a shaft revolution sensor which provides a feedback pulse train representative of the actual speed of the motor. An internal digital timing signal generator provides a reference signal which is compared with the feedback signal in a computing unit to provide a motor control signal. The motor control signal is a weighted linear sum of a speed error voltage, a phase error voltage, and a drift error voltage, each of which is computed anew with each revolution of the motor shaft. The speed error signal is generated by a novel vernier-logic circuit which is drift-free and highly sensitive to small speed changes. The phase error is also computed by digital logic, with adjustable sensitivity around a 0 mid-scale value. The drift error signal, generated by long-term counting of the phase error, is used to compensate for any slow changes in the average friction drag on the motor. An auxillary drift-byte status sensor prevents any disruptive overflow or underflow of the drift-error counter. An adjustable clocked-delay unit is inserted between the controller and the source of the reference pulse train to permit phase alignment of the rotor to any desired offset angle. The stator windings of the motor are driven by two amplifiers which are provided with input signals having the proper quadrature relationship by an exciter unit consisting of a voltage controlled oscillator, a binary counter, a pair of read-only memories, and a pair of digital-to-analog converters.

  18. Current control in inertial Brownian motors by noise recycling

    Science.gov (United States)

    Jia, Zheng-Lin; Li, Kai-Yi; Li, Chun; Yang, Chun-Yan; Mei, Dong-Cheng

    2015-03-01

    The transport properties of an inertial Brownian motor were numerically studied in the presence of recycled noise, which is obtained by re-injecting a fraction of the primary white noise after a processing time, being introduced into the system in a multiplicative way. The simulation results indicate that various parameters such as the external driving force, the friction coefficient, the mass of the particle, the recycling strength, and the delay time can induce the current reversal phenomenon when the sign of the recycling strength is in agreement with the sign of the external bias force, otherwise the current reversal cannot be observed. Additionally, the asymptotic mean velocity as a function of the delay time of the recycled noise always shows a resonance-like behavior with the presence of a maximum current. These results demonstrate that the delay time and the recycling strength of the recycled noise can be used as the feasible and flexible control parameters for the amplitude and direction of the current.

  19. [Strategies aiming to control hyperphosphatemia in chronic kidney disease].

    Science.gov (United States)

    Ureña Torres, Pablo Antonio

    2017-04-01

    Chronic kidney disease is known to be associated with phosphate retention. The mechanisms are complex and the early increase in serum phosphate levels in chronic kidney disease is not strictly related to the dietary phosphate load or to the degree of phosphate retention. It also implicates the activity of intestinal sodium-phosphate cotransporters, the degree of bone turnover and the retention and/or phosphate release from the skeleton, and the feedback mechanisms regulating the phosphaturia. Indeed, the increase in serum phosphate levels is only a reflection of underlying complex mechanisms, and many important factors play a role including parathyroid hormone, vitamin D, fibroblast growth factor 23 (FGF23), and others. Hyperphosphatemia increases the risk of cardiovascular morbidity and mortality in chronic kidney disease as well as in subjects with normal renal function. Oral phosphate binders are prescribed in patients with chronic kidney disease and in those treated by dialysis, to prevent intestinal absorption of dietary phosphate and reduce serum phosphate. In prospective observational studies, they have been shown to decrease all-cause and cardiovascular mortality risk. However, different problems have been associated with currently available phosphate binders including the induction of a positive calcium balance and impaired outcomes with calcium-based phosphate binders or increased costs with non-calcium-based phosphate binders. Iron-based phosphate binders represent a new class of phosphate binders. The aim of this article is to provide an update review of the pathophysiological mechanisms leading and maintaining elevated serum phosphate levels in patients with chronic kidney disease and patients in dialysis, and the educational, nutritional, and therapeutic strategies that can be undertaken to control the hyperphosphatemia. Copyright © 2017 Association Société de néphrologie. Published by Elsevier Masson SAS. All rights reserved.

  20. Control strategies for crane systems: A comprehensive review

    Science.gov (United States)

    Ramli, Liyana; Mohamed, Z.; Abdullahi, Auwalu M.; Jaafar, H. I.; Lazim, Izzuddin M.

    2017-10-01

    Crane systems are tremendously utilised in numerous heavy load transportation industries, and therefore, the control of crane systems is a well-established research field. As the last review paper was published more than a decade ago, there is a lack of collected and organised information regarding the latest and the newest updates on control strategies for crane control systems. Hence, this paper presents a comprehensive review of crane control strategies discussing the latest research works during the years from 2000 to 2016. Various crane types and control issues are highlighted, followed by the main focus of this paper, an extensive review of the control schemes for diverse types of crane systems that have been carried out in the 21st century. A brief review on modelling of single-pendulum and double-pendulum crane systems is also given. In addition, anti-sway control systems for industrial cranes that are available on the market is described. This paper summarises most of the related work and also pays a special focus on research trends regarding the control of crane systems that have been previously published in the literature. It is envisaged that this review paper will be helpful to new researchers when identifying research directions for this particular area of interest.