WorldWideScience

Sample records for supervised stability control

  1. Microprocessor supervised stability control system for the united power system of Middle Volga in fault conditions

    Energy Technology Data Exchange (ETDEWEB)

    Berdnikov, V I; Birgel, E R; Kovalev, V D; Kuznestov, A N

    1994-12-31

    The development of the 500 kV UPS of Middle Volga, the complication of its configuration and operating conditions particularly in connection with concentration of the generating power at Balakovo NPS have aggravated the problem of stability of the Middle Volga UPS when high power is transmitted along the 500 kV transient system. In this case the necessity for improving control actions` dosage accuracy has also appeared. This work discusses solution to the above mentioned issue. (author) 3 figs.

  2. SUPERVISION OF CREDIT INSTITUTIONS SIGNIFICANT RISKS TO FINANCIAL STABILITY

    Directory of Open Access Journals (Sweden)

    LUCIAN-ION MEDAR

    2014-12-01

    Full Text Available Financial stability of Romanian banking system is determined by the constant supervision of credit institutions significant risks. Accession of Romania to Union Banking requires the signing of a linked protocol between the central bank and European Central Bank regarding prudential supervision to ensure financial stability. This means that from the next year, the central bank will impose a new supervision of credit institutions in our country. And especially to those credit institutions that do not fall under European supervisors, according to the procedures of the ECB. Through this study we propose to specify the main elements of management of significant risks to ensure financial stability.

  3. State Radiation Protection Supervision and Control

    International Nuclear Information System (INIS)

    2003-01-01

    Radiation Protection Centre is carrying state supervision and control of radiation protection. The main objective of state supervision and control of radiation protection is assessing how licensees comply with requirements of the appropriate legislation and enforcement. Summary of inspections conducted in 2002 is presented

  4. State Radiation Protection Supervision and Control

    CERN Document Server

    2002-01-01

    Radiation Protection Centre is carrying state supervision and control of radiation protection. The main objective of state supervision and control of radiation protection is assessing how licensees comply with requirements of the appropriate legislation and enforcement. Summary of inspections conducted in 2002 is presented.

  5. State Supervision and Control of Radiation Protection

    CERN Document Server

    2001-01-01

    Radiation Protection Centre is carrying state supervision and control of radiation protection. The main objective of state supervision and control of radiation protection is assessing how licensees comply with requirements of the appropriate legislation and enforcement. Summary of inspections conducted in 1999-2001 is presented.

  6. Impact of regulation and supervision on European banks’ stability

    Directory of Open Access Journals (Sweden)

    Faten Ben Bouheni

    2014-03-01

    Full Text Available This article applies the Generalized Method of Moments technique for dynamic panels, using bank-level data for the selected European countries over the period 2005 to 2011, to investigate the impact of regulation and supervision on risk taking. Three conclusions are reached. First, in France, Germany and UK, restriction on bank activities boosts banking stability. However, supervisors’ power and capital adequacy encourage risk taking. Second, in Italy, Greece and Spain, we find that with more supervisors’ power, largest banks tend to take greater risks and strengthening regulation and supervision weakens the bank’s stability. However, the capital requirements decrease the risk taking. Third, strengthening regulatory and supervisory framework, and compliance with Basel principles enhance financial stability in Europe. These different results between European countries show that the application of regulation and supervision depends on the monitoring mode and the rhythm of application of regulatory policies

  7. Bank, Banking System, Macroprudential Supervision, Stability of Banking System

    Directory of Open Access Journals (Sweden)

    Tetiana Vasilyeva

    2016-10-01

    assets to short term liabilities ratio and cost to income ratio. Empirical results of the research found out that grate damage to the stability of banking system has some parameters of banking activity, that’s why the main purpose of the regulation by the National Bank of Ukraine should be strengthening of macroprudential supervision and intensification of adaptation of Basel II and Basel III requirements

  8. Intelligent supervision control for the VASPS separator

    Energy Technology Data Exchange (ETDEWEB)

    Melo, A.V.; Mendes, J.R.P. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil)], E-mail: jricardo@dep.fem.unicamp.br; Serapiao, A.B.S [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Rio Claro, SP (Brazil)

    2007-10-15

    The Vertical Annular Separation and Pumping System, VASPS, has been applied to low-pressure subsea wells with high gas production potential. In this system, the separation is carried out on the sea bed, thus allowing the monophase transmission through different pipelines. In the present work, an analysis has been established between two conceptually distinct models for the control system, which is under development and uses the Fuzzy Control technique for the Electrical Submersible Pump (ESP) speed selection. The contrast is held on the objective of each controller, placing the operational performance against the stability of the control signal, which leads to the exploration of many specific aspects of the system, its behavior and requirements. (author)

  9. THE IMPORTANCE OF BANKING SUPERVISION IN ENSURING FINANCIAL STABILITY

    Directory of Open Access Journals (Sweden)

    CĂRUNTU GENU ALEXANDRU

    2014-12-01

    Full Text Available Financial stability plays a vital role in terms of the financial system and the economy as a whole. Analysis and management of risks in the banking sector in order to achieve the financial stability of the whole banking system requires the use of established methods in modern management of risk. The financial crisis has demonstrated certain limits in terms of efficient management of risk. In this respect supervisory authorities have developed a number of methods and techniques to detect, monitor and amount of risk. In the present context, to enhance the stability of the banking system and prevent systemic risk, it is proposed to revise the Basel II Agreement. It was necessary to review the existing prudential regulations defining, embodied in Basel III. This new agreement brings more clarity in the financial and banking sector, addresses a wider range of risks, providing a better regulator

  10. Fuzzy Logic Supervised Teleoperation Control for Mobile Robot

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The supervised teleoperation control is presented for a mobile robot to implement the tasks by using fuzzy logic. The teleoperation control system includes joystick based user interaction mechanism, the high level instruction set and fuzzy logic behaviors integrated in a supervised autonomy teleoperation control system for indoor navigation. These behaviors include left wall following, right wall following, turn left, turn right, left obstacle avoidance, right obstacle avoidance and corridor following based on ultrasonic range finders data. The robot compares the instructive high level command from the operator and relays back a suggestive signal back to the operator in case of mismatch between environment and instructive command. This strategy relieves the operator's cognitive burden, handle unforeseen situations and uncertainties of environment autonomously. The effectiveness of the proposed method for navigation in an unstructured environment is verified by experiments conducted on a mobile robot equipped with only ultrasonic range finders for environment sensing.

  11. Supervision and atuomatic control of robotics systems in nuclear environments

    International Nuclear Information System (INIS)

    Benner, J.; Leinemann, K.

    1992-01-01

    The paper describes new developments in controlling remote handling systems for nuclear applications. The main emphasis is to use robotic equipment and methods for reaching a high degree of system autonomy. A remote handling workstation concept is described, supporting various stages of mission planning and supervision by means of suited geometrical, procedural and functional models. The presented control system enables easy switching between semi-autonomous and manual task execution and sensor data integration. Some experimental results of a prototypic implementation are also described

  12. Supervision and automatic control of robotic systems in nuclear environments

    International Nuclear Information System (INIS)

    Benner, J.; Leinemann, K.

    1992-01-01

    This paper describes new developments in controlling remote handling systems for nuclear applications. The main emphasis is to use robotic equipment and methods for reaching a high degree of system autonomy. A remote handling workstation concept is described, supporting various stages of mission planning and supervision by means of suited geometrical, procedural and functional models. The presented control system enables easy switching between semi-autonomous and manual task execution and sensor data integration. Some experimental results of a prototypic implementation are also described

  13. Development and implementation of full-automatic supervision and control programme for CEFR refueling control system

    International Nuclear Information System (INIS)

    Zhu Hao; Dong Shengguo; Ma Hongsheng; Zhao Lixia

    2011-01-01

    In order to make the process of CEFR refueling more convenient and reliable, the computer supervision and control system was designed according to the CEFR refueling technology. Meanwhile, the supervision and control function and database function were developed on the basis of KingView and SQL Server2000. The fuel of reactor core was fully loaded by the system, and full-automation of CEFR refueling process was implemented. (authors)

  14. Controlled study of child health supervision: behavioral results.

    Science.gov (United States)

    Guteilus, M F; Kirsch, A D; MacDonald, S; Brooks, M R; McErlean, T

    1977-09-01

    Extensive child health supervision, with emphasis on counseling and anticipatory guidance, was provided for the first three years of life to an experimental series of 47 normal first-born black infants from low-income families living in the environs of Children's Hospital in Washington, D.C. The mothers were unmarried schoolgirls in normal physical and mental health. A control series consisted of 48 similar mother-child dyads from the same area. Data were collected, in part by an outside evaluator, at yearly intervals on both experimental and control series in a form suitable for coding on computer cards. Comparison of differences in behavioral results between the two series showed statistically significant findings in favor of the experimental children, as well as numerous favorable trends during the first six years of life. Positive effects became evident in diet and eating, habits, in some developmental problems of growing up (such as toilet training), and in certain abstract qualities including self-confidence. Significant differences were also noted between the experimental and control mothers for various child rearing practices and personality characteristics. No significant difference or trend favored the control series. We believe that a causal relationship existed between the intervention and at least some of the significant findings.

  15. 28 CFR 570.43 - Inmates requiring a high degree of control and supervision.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Inmates requiring a high degree of control and supervision. 570.43 Section 570.43 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE COMMUNITY PROGRAMS AND RELEASE COMMUNITY PROGRAMS Escorted Trips § 570.43 Inmates requiring a high degree of control and supervision. Only the...

  16. The State Supervision (Control in the Sphere of Economic Activity: International Experience Relevant for Ukraine

    Directory of Open Access Journals (Sweden)

    Vdovychenko Larysa Yu.

    2018-01-01

    Full Text Available The attempts in the process of decentralization in Ukraine to implement the best international practices of the State supervision (control in the sphere of economic activity, in the process which depends on the status of deregulation and development of entrepreneurship, have caused the topicality of the problem set. The article is aimed at analyzing the international experience of application of the State supervision (control instruments in the sphere of economic activity and determination of the directions of their use in Ukraine. The stages of reforms of the control and supervision activity both in foreign countries and in Ukraine were considered. The directions and measures on creation of effective system of the State supervision (control in the sphere of economic activity, applied in the world countries, were systematized. Both the positive and the negative aspects of use of foreign instruments of the State supervision (control in the sphere of economic activity in Ukraine have been defined. Recommendations on formation of the national complex system of functioning of control-supervision activity have been given.

  17. Autonomous Supervision and Control of Parametric Roll Resonance

    DEFF Research Database (Denmark)

    Galeazzi, Roberto

    therefore two objectives. The first is to develop methods for detection of the inception of parametric roll resonance. The second is to develop control strategies to stabilize the motion after parametric roll has started. Stabilisation of parametric roll resonance points to two possible courses of action...... strategies are then combined to stabilise parametric roll resonance within few roll cycles. Limitations on the maximum stabilisable roll angle are analysed and linked to the ii slew rate saturation and hydrodynamic stall characteristics of the fin stabilisers. The study on maximum stabilisable roll angle...... leads to the requirements for early detection. Two novel detectors are proposed, which work within a shorttime prediction horizon, and issue early warnings of parametric roll inception within few roll cycles from its onset. The main idea behind these detection schemes is that of exploiting the link...

  18. Use of non-destructive controls for the supervision of operating apparatus

    International Nuclear Information System (INIS)

    Ducrot, Bernard.

    1978-01-01

    The scope of application of this paper, that is standard apparatus whether pressure or not, is presented. Then the particular problem of the use of non-destructive controls for the supervision of operating apparatus is outlined. The subject of how to exercise that supervision is developed by replying to four questions: why, when, how, who. A summary of the main advantages and disadvantages of the different control techniquess used is given in a tabular form. A last part deals with a series of practical applications, which show at the same time the interest and difficulties of that type of control [fr

  19. Control of locomotor stability in stabilizing and destabilizing environments.

    Science.gov (United States)

    Wu, Mengnan/Mary; Brown, Geoffrey; Gordon, Keith E

    2017-06-01

    To develop effective interventions targeting locomotor stability, it is crucial to understand how people control and modify gait in response to changes in stabilization requirements. Our purpose was to examine how individuals with and without incomplete spinal cord injury (iSCI) control lateral stability in haptic walking environments that increase or decrease stabilization demands. We hypothesized that people would adapt to walking in a predictable, stabilizing viscous force field and unpredictable destabilizing force field by increasing and decreasing feedforward control of lateral stability, respectively. Adaptations in feedforward control were measured using after-effects when fields were removed. Both groups significantly (pfeedforward adaptions to increase control of lateral stability. In contrast, in the destabilizing field, non-impaired subjects increased movement variability (p0.05). When the destabilizing field was removed, increases in movement variability persisted (pfeedforward decreases in resistance to perturbations. Published by Elsevier B.V.

  20. 17 CFR 240.17i-4 - Internal risk management control system requirements for supervised investment bank holding...

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Internal risk management... Supervised Investment Bank Holding Company Rules § 240.17i-4 Internal risk management control system...) As part of its internal risk management control system, a supervised investment bank holding company...

  1. Closely Supervised Reactive Control of an Uninhabited Aerial Vehicle

    National Research Council Canada - National Science Library

    Glassco, Roy

    2000-01-01

    ...) or by using the Global Positioning System (GPS). This thesis proposes an alternative control method that incorporates some of the beneficial aspect of both fully manual and fully autonomous operation...

  2. Fuzzy controller for real time supervision of nuclear power reactor

    International Nuclear Information System (INIS)

    Bala Subramanian, R.

    2012-01-01

    Generally nuclear energy provides about 60% of the whole electricity production. A modulation of the nuclear power plants must be able to respond to the demand on the network. The pressurized water nuclear reactor has to yield correctly a load set point. Fundamentally, two parameters are concerned in leading this task to a successful conclusion: the power axial-offset and the control rods position. The focus of this study is the automation of the control of the power axial-offset by adding soluble boron and by minimizing the volume flows through the water pump. It is also important to take into consideration the liquid waste volume. Water or boron is injected into the reactor primary circuit. At the present time this task is still performed manually by an operator, for all previous attempts to automate it failed. That device, sketchily described in the paper, gave rise to the development of a real-time fuzzy controller for the power axial-offset and the control rods insertion in a pressurized water reactor (PWR). The fuzzy controller, which is the main subject of the paper, expresses more naturally the human expertise, thus avoiding the previous issue of empirical tunings. It was implemented in simulation using Matlab-Simulink on a Sun workstation. Two realistic tests discussed show that the fuzzy controller runs as efficiently as an expert operator does

  3. Control and digital supervision of sub-stations

    International Nuclear Information System (INIS)

    Martin, O; Messie, M; Labrouche, G. de la

    1996-01-01

    The article is about the electromagnetic compatibility, security of the operation, requirements evolution and techniques among other aspects. It concludes that the dynamics of the progress associated with digital technologies should therefore, to control by means of a rational development that requires of tools and methods that are at the same time with the technological and economic jump, the jump should also be cultural concerning the coming of a new field of knowledge, the prosecution of data

  4. Remote Supervision and Control of Air Conditioning Systems in Different Modes

    Science.gov (United States)

    Rafeeq, Mohammed; Afzal, Asif; Rajendra, Sree

    2018-01-01

    In the era of automation, most of the application of engineering and science are interrelated with system for optimal operation. To get the efficient result of an operation and desired response, interconnected systems should be controlled by directing, regulating and commanding. Here, air conditioning (AC) system is considered for experimentation, to supervise and control its functioning in both, automated and manual mode. This paper reports the work intended to design and develop an automated and manual AC system working in remote and local mode, to increase the level of comfort, easy operation, reducing human intervention and faults occurring in the system. The Programmable Logical Controller (PLC) and Supervisory Control and Data Acquisition (SCADA) system were used for remote supervision and monitoring of AC systems using series ninety protocol and remote terminal unit modbus protocol as communication module to operate in remote mode. PLC was used as remote terminal for continuous supervision and control of AC system. SCADA software was used as a tool for designing user friendly graphical user interface. The proposed SCADA AC system successfully monitors and controls in accordance within the parameter limits like temperature, pressure, humidity and voltage. With all the features, this designed system is capable of efficient handling of the resources like the compressor, humidifier etc., with all the levels of safety and durability. This system also maintains the temperature and controls the humidity of the remote location and also looks after the health of the compressor.

  5. Parental supervision for their children's toothbrushing: Mediating effects of planning, self-efficacy, and action control.

    Science.gov (United States)

    Hamilton, Kyra; Cornish, Stephen; Kirkpatrick, Aaron; Kroon, Jeroen; Schwarzer, Ralf

    2018-05-01

    With 60-90% of children worldwide reportedly experiencing dental caries, poor oral health in the younger years is a major public health issue. As parents are important to children's oral hygiene practices, we examined the key self-regulatory behaviours of parents for supervising their children's toothbrushing using the health action process approach. Participants (N = 281, 197 mothers) comprised Australian parents of 2- to 5-year-olds. A longitudinal design was used to investigate the sequential mediation chain for the effect of intention (Time 1) on parental supervision for their youngest child's toothbrushing (Time 3), via self-efficacy and planning (Time 2), and action control (Time 3). A latent-variable structural equation model, controlling for baseline behaviour and habit, revealed significant indirect effects from intention via self-efficacy and action control and intention via planning and action control, on parental supervision behaviour. The model was a good fit to the data, explaining 74% of the variance in parents' supervising behaviour for their children's toothbrushing. While national recommendations are provided to guide parents in promoting good oral hygiene practices with their children, current results show the importance of going beyond simple knowledge transmission to support parents' intentions to supervise their children's toothbrushing actually materialize. Current findings make a significant contribution to the cumulative empirical evidence regarding self-regulatory components in health behaviour change and can inform intervention development to increase parents' participation in childhood oral hygiene practices, thus helping to curb rising oral health conditions and diseases. Statement of contribution What is already known on this subject? Self-regulatory skills are important to translate intentions into behaviour. Self-efficacy, planning, and action control are key self-regulatory skills for behaviour change. What does this study add

  6. Problems and solutions in the field of improving control and supervision activities in the construction sector

    Science.gov (United States)

    Dikareva, Varvara; Mostovaya, Anna

    2018-03-01

    The improvement of control and supervision activities in high-rise construction is an important goal of the state. In the paper, the author considered the initiatives of the state in terms of improving the control activity. He shows the main approaches that will be applied by the state. The application of information and communication technologies in control activities is described in detail. It was noted that the quality of the regulation of various procedures remains a serious issue. At the same time, modern innovations in the field of control should take into account the increasing volumes of data and information about various economic processes.

  7. Theoretical Considerations on the Organisation of Banking Supervision and Internal Banking Control

    Directory of Open Access Journals (Sweden)

    Loredana CIURLAU

    2016-09-01

    Full Text Available Prudential supervision of the entities wich make up the banking system from Romania constitute one of the main tasks of the National Bank of Romania which are characterized by a specificity that distinguishes it from its control activities in other areas of social and economic activity. This attribution becomes essential in the activity of the National Bank of Romania as long as the legislature authorizes this institution with an exclusive quality of national authority in this area.

  8. New stability and stabilization for switched neutral control systems

    International Nuclear Information System (INIS)

    Xiong Lianglin; Zhong Shouming; Ye Mao; Wu Shiliang

    2009-01-01

    This paper concerns stability and stabilization issues for switched neutral systems and presents new classes of piecewise Lyapunov functionals and multiple Lyapunov functionals, based on which, two new switching rules are introduced to stabilize the neutral systems. One switching rule is designed from the solution of the so-called Lyapunov-Metzler linear matrix inequalities. The other is based on the determination of average dwell time computed from a new class of linear matrix inequalities (LMIs). And then, state-feedback control is derived for the switched neutral control system mainly based on the state switching rules. Finally, three examples are given to demonstrate the effectiveness of the proposed method.

  9. Development of a web-based remote load supervision and control system

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Wei-Fu; Wu, Yu-Chi; Chiu, Chui-Wen [National United University, Miao-Li (Taiwan). Department of Electrical Engineering

    2006-07-15

    The ability to remotely acquire information and even to control appliances/devices at fingertips over the Internet is becoming desirable to the general public as well as professionals. In this paper, a web-based remote electric load supervision and control (WBRELSAC) system with automatic meter reading and demand control via programmable logic controllers (PLCs) is presented. For both utilities and industrial/commercial customers, the electric load supervision and control (ELSAC) system is a critical function to their load management. However, most high voltage customers do not have enough capital to build a regular-scale supervisory control and data acquisition system as the one for utilities. Therefore, we adopt the industrial-widely-used PLCs in WBRELSAC. In order to make a non-web-based PLC become web-controllable, we develop a graphical-control interface and utilize Internet techniques to implement our system. Based on the performance test conducted under the Laboratory environment, the proposed WBRELSAC architecture is cost-effective and suitable for industrial applications. (author)

  10. MATLAB Stability and Control Toolbox Trim and Static Stability Module

    Science.gov (United States)

    Kenny, Sean P.; Crespo, Luis

    2012-01-01

    MATLAB Stability and Control Toolbox (MASCOT) utilizes geometric, aerodynamic, and inertial inputs to calculate air vehicle stability in a variety of critical flight conditions. The code is based on fundamental, non-linear equations of motion and is able to translate results into a qualitative, graphical scale useful to the non-expert. MASCOT was created to provide the conceptual aircraft designer accurate predictions of air vehicle stability and control characteristics. The code takes as input mass property data in the form of an inertia tensor, aerodynamic loading data, and propulsion (i.e. thrust) loading data. Using fundamental nonlinear equations of motion, MASCOT then calculates vehicle trim and static stability data for the desired flight condition(s). Available flight conditions include six horizontal and six landing rotation conditions with varying options for engine out, crosswind, and sideslip, plus three take-off rotation conditions. Results are displayed through a unique graphical interface developed to provide the non-stability and control expert conceptual design engineer a qualitative scale indicating whether the vehicle has acceptable, marginal, or unacceptable static stability characteristics. If desired, the user can also examine the detailed, quantitative results.

  11. Performance analyses of the communication networks of a modern supervision and control system of research reactors

    International Nuclear Information System (INIS)

    El-Madbouly, E.I.; Shaat, M.K.; Shokr, A.M.; Elrefaei, G.H.

    2009-01-01

    The functions of the Instrumentation and Control (I and C) system in research reactors, the changes in its design according to the advances in the technology, and the internationally established safety requirements on the design and operational performance of this system are reviewed. The main features of the communication networks commonly used in the Supervision and Control systems (SCS) are presented. A methodology for the performance analysis of the communication networks of computer-based distributed SCS is developed and presented along with discussions. Application of this methodology to a modern SCS of a typical research reactor is illustrated. (orig.)

  12. Performance analyses of the communication networks of a modern supervision and control system of research reactors

    Energy Technology Data Exchange (ETDEWEB)

    El-Madbouly, E.I. [Menoufia Univ., Menouf (Egypt). Faculty of Electronics Engineering; Shaat, M.K.; Shokr, A.M.; Elrefaei, G.H. [Atomic Energy Authority, Abouzabal (Egypt). Egypt Second Research Reactor

    2009-04-15

    The functions of the Instrumentation and Control (I and C) system in research reactors, the changes in its design according to the advances in the technology, and the internationally established safety requirements on the design and operational performance of this system are reviewed. The main features of the communication networks commonly used in the Supervision and Control systems (SCS) are presented. A methodology for the performance analysis of the communication networks of computer-based distributed SCS is developed and presented along with discussions. Application of this methodology to a modern SCS of a typical research reactor is illustrated. (orig.)

  13. Matlab Stability and Control Toolbox: Trim and Static Stability Module

    Science.gov (United States)

    Crespo, Luis G.; Kenny, Sean P.

    2006-01-01

    This paper presents the technical background of the Trim and Static module of the Matlab Stability and Control Toolbox. This module performs a low-fidelity stability and control assessment of an aircraft model for a set of flight critical conditions. This is attained by determining if the control authority available for trim is sufficient and if the static stability characteristics are adequate. These conditions can be selected from a prescribed set or can be specified to meet particular requirements. The prescribed set of conditions includes horizontal flight, take-off rotation, landing flare, steady roll, steady turn and pull-up/ push-over flight, for which several operating conditions can be specified. A mathematical model was developed allowing for six-dimensional trim, adjustable inertial properties, asymmetric vehicle layouts, arbitrary number of engines, multi-axial thrust vectoring, engine(s)-out conditions, crosswind and gyroscopic effects.

  14. DC microgrid power flow optimization by multi-layer supervision control. Design and experimental validation

    International Nuclear Information System (INIS)

    Sechilariu, Manuela; Wang, Bao Chao; Locment, Fabrice; Jouglet, Antoine

    2014-01-01

    Highlights: • DC microgrid (PV array, storage, power grid connection, DC load) with multi-layer supervision control. • Power balancing following power flow optimization while providing interface for smart grid communication. • Optimization under constraints: storage capability, grid power limitations, grid time-of-use pricing. • Experimental validation of DC microgrid power flow optimization by multi-layer supervision control. • DC microgrid able to perform peak shaving, to avoid undesired injection, and to make full use of locally energy. - Abstract: Urban areas have great potential for photovoltaic (PV) generation, however, direct PV power injection has limitations for high level PV penetration. It induces additional regulations in grid power balancing because of lacking abilities of responding to grid issues such as reducing grid peak consumption or avoiding undesired injections. The smart grid implementation, which is designed to meet these requirements, is facilitated by microgrids development. This paper presents a DC microgrid (PV array, storage, power grid connection, DC load) with multi-layer supervision control which handles instantaneous power balancing following the power flow optimization while providing interface for smart grid communication. The optimization takes into account forecast of PV power production and load power demand, while satisfying constraints such as storage capability, grid power limitations, grid time-of-use pricing and grid peak hour. Optimization, whose efficiency is related to the prediction accuracy, is carried out by mixed integer linear programming. Experimental results show that the proposed microgrid structure is able to control the power flow at near optimum cost and ensures self-correcting capability. It can respond to issues of performing peak shaving, avoiding undesired injection, and making full use of locally produced energy with respect to rigid element constraints

  15. Preventing Urinary Incontinence With Supervised Prenatal Pelvic Floor Exercises: A Randomized Controlled Trial.

    Science.gov (United States)

    Fritel, Xavier; de Tayrac, Renaud; Bader, Georges; Savary, Denis; Gueye, Ameth; Deffieux, Xavier; Fernandez, Hervé; Richet, Claude; Guilhot, Joëlle; Fauconnier, Arnaud

    2015-08-01

    To compare, in an unselected population of nulliparous pregnant women, the postnatal effect of prenatal supervised pelvic floor muscle training with written instructions on postpartum urinary incontinence (UI). In a randomized controlled trial in two parallel groups, 282 women were recruited from five university teaching hospitals in France and randomized during the second trimester of pregnancy. The physiotherapy group received prenatal individually supervised exercises. Both groups received written instructions about how to perform exercises at home. Women were blindly assessed at baseline, end of pregnancy, and 2 and 12 months postpartum. The primary outcome measured was UI severity, assessed with an International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form score (range 0-21; 1-5 is slight UI) at 12 months postpartum; other outcomes were UI prevalence and pelvic floor troubles assessed using self-administered questionnaires. To give a 1-point difference in UI severity score, we needed 91 women in each group (standard deviation 2.4, α=0.05, β=0.20, and bilateral analysis). Between February 2008 and June 2010, 140 women were randomized in the physiotherapy group and 142 in the control group. No difference was observed between the two groups in UI severity, prevalence, or pelvic floor troubles at baseline, end of pregnancy, and at 2 and 12 months postpartum. At 12 months postpartum, the primary outcome was available for 190 women (67.4%); mean UI severity was 1.9 in the physiotherapy group compared with 2.1 in the control group (P=.38). Prenatal supervised pelvic floor training was not superior to written instructions in reducing postnatal UI. ClinicalTrials.gov; www.clinicaltrials.gov, NCT00551551. I.

  16. Supervising and Controlling Unmanned Systems: A Multi-Phase Study with Subject Matter Experts.

    Science.gov (United States)

    Porat, Talya; Oron-Gilad, Tal; Rottem-Hovev, Michal; Silbiger, Jacob

    2016-01-01

    Proliferation in the use of Unmanned Aerial Systems (UASs) in civil and military operations has presented a multitude of human factors challenges; from how to bridge the gap between demand and availability of trained operators, to how to organize and present data in meaningful ways. Utilizing the Design Research Methodology (DRM), a series of closely related studies with subject matter experts (SMEs) demonstrate how the focus of research gradually shifted from "how many systems can a single operator control" to "how to distribute missions among operators and systems in an efficient way". The first set of studies aimed to explore the modal number, i.e., how many systems can a single operator supervise and control. It was found that an experienced operator can supervise up to 15 UASs efficiently using moderate levels of automation, and control (mission and payload management) up to three systems. Once this limit was reached, a single operator's performance was compared to a team controlling the same number of systems. In general, teams led to better performances. Hence, shifting design efforts toward developing tools that support teamwork environments of multiple operators with multiple UASs (MOMU). In MOMU settings, when the tasks are similar or when areas of interest overlap, one operator seems to have an advantage over a team who needs to collaborate and coordinate. However, in all other cases, a team was advantageous over a single operator. Other findings and implications, as well as future directions for research are discussed.

  17. Hybrid Intelligent Control for Submarine Stabilization

    Directory of Open Access Journals (Sweden)

    Minghui Wang

    2013-05-01

    Full Text Available Abstract While sailing near the sea surface, submarines will often undergo rolling motion caused by wave disturbance. Fierce rolling motion seriously affects their normal operation and even threatens their security. We propose a new control method for roll stabilization. This paper studies hybrid intelligent control combining a fuzzy control, a neural network and extension control technology. Every control strategy can achieve the ideal control effect within the scope of its effective control. The neuro-fuzzy control strategy is used to improve the robustness of the controller. The speed control strategy and the course control strategy are conducted to extend the control range. The paper also proposes the design of the controller and carries out the simulation experiment in different sea conditions. The simulation results show that the control method proposed can indeed effectively improve the control performance of submarine stabilization.

  18. Supervising and Controlling Unmanned Systems: A Multi-Phase Study with Subject Matter Experts

    Science.gov (United States)

    Porat, Talya; Oron-Gilad, Tal; Rottem-Hovev, Michal; Silbiger, Jacob

    2016-01-01

    Proliferation in the use of Unmanned Aerial Systems (UASs) in civil and military operations has presented a multitude of human factors challenges; from how to bridge the gap between demand and availability of trained operators, to how to organize and present data in meaningful ways. Utilizing the Design Research Methodology (DRM), a series of closely related studies with subject matter experts (SMEs) demonstrate how the focus of research gradually shifted from “how many systems can a single operator control” to “how to distribute missions among operators and systems in an efficient way”. The first set of studies aimed to explore the modal number, i.e., how many systems can a single operator supervise and control. It was found that an experienced operator can supervise up to 15 UASs efficiently using moderate levels of automation, and control (mission and payload management) up to three systems. Once this limit was reached, a single operator's performance was compared to a team controlling the same number of systems. In general, teams led to better performances. Hence, shifting design efforts toward developing tools that support teamwork environments of multiple operators with multiple UASs (MOMU). In MOMU settings, when the tasks are similar or when areas of interest overlap, one operator seems to have an advantage over a team who needs to collaborate and coordinate. However, in all other cases, a team was advantageous over a single operator. Other findings and implications, as well as future directions for research are discussed. PMID:27252662

  19. Scada Systems – Control, Supervision and Data Acquisition for the Power Plants Settled on a Stream (Part 2

    Directory of Open Access Journals (Sweden)

    Cosmin Ursoniu

    2015-09-01

    Full Text Available Scada (supervisory control and data acquisition is a complex system that supervises and controls an industrial process and performs several functions. A human machine interface will also be presented and how the process in a power plant is controlled and supervised through it by the operator. The main screen will be described (which is a global view of the hydro unit and what the operator can see and what he can press to control the power plants process also a few more screens will be presented for auxiliary installations and it will be described what the operator can see and what he can do to control the installation.

  20. Scada Systems – Control, Supervision and Data Acquisition for the Power Plants Settled on a Stream (Part 1

    Directory of Open Access Journals (Sweden)

    Cosmin Ursoniu

    2015-09-01

    Full Text Available Scada (supervisory control and data acquisition is a complex system that supervises and control an industrial process and performs several functions. A human machine interface will also be presented and how the process in a power plant is controlled and supervised through it by the operator. The main screen will be described (which is a global view of the hydro unit and what the operator can see and what he can press to control the power plants process also a few more screens will be presented for auxiliary installations and it will be described what the operator can see and what he can do to control the installation.

  1. Power system stability modelling, analysis and control

    CERN Document Server

    Sallam, Abdelhay A

    2015-01-01

    This book provides a comprehensive treatment of the subject from both a physical and mathematical perspective and covers a range of topics including modelling, computation of load flow in the transmission grid, stability analysis under both steady-state and disturbed conditions, and appropriate controls to enhance stability.

  2. Prospects of supervising service development as the tool of input quality control

    Science.gov (United States)

    Sizov, A.; Tretyakov, K.; Boyarko, G.; Shenderova, I.; Ostranitsyn, I.

    2016-09-01

    Supervising provides a foothold in the Russian Federation domestic market of oilfield services. Despite the rapid growth of supervising services market, there is still a definite demand in developing this domain. The authors consider the implementation of supervising in Russian oil and gas industry sector, as well as the possible execution paths of its improvement and development.

  3. The Urine Marker Test: An Alternative Approach to Supervised Urine Collection for Doping Control.

    Science.gov (United States)

    Elbe, Anne-Marie; Jensen, Stine Nylansted; Elsborg, Peter; Wetzke, Monika; Woldemariam, Getachew A; Huppertz, Bernd; Keller, Ruprecht; Butch, Anthony W

    2016-01-01

    Urine sample collection for doping control tests is a key component of the World Anti-Doping Agency's fight against doping in sport. However, a substantial number of athletes experience difficulty when having to urinate under supervision. Furthermore, it cannot always be ensured that athletes are actually delivering their own urine. A method that can be used to alleviate the negative impact of a supervised urination procedure and which can also identify urine as coming from a specific athlete is the urine marker test. Monodisperse low molecular weight polyethylene glycols (PEGs) are given orally prior to urination. Urine samples can be traced to the donor by analysis of the PEGs previously given. The objective of this study was to investigate the use of the urine marker during urine doping control testing. Two studies investigated athletes' acceptance of this new method via two questionnaires (n = 253). Furthermore, a third study (n = 91) investigated whether ingestion of the marker can identify the urine as coming from a specific person and whether the marker interferes with the detection of prohibited substances. The results indicate that this new method finds wide acceptance both from athletes who have only heard about the procedure and those who have actually tested the new method. Furthermore, the marker, which can identify urine as coming from a specific person, does not interfere with the detection of prohibited substances.

  4. Supervised physical exercise during pregnancy improves health perception. Randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Mireia Peláez

    2013-07-01

    Full Text Available Aim: To investigate the influence of a moderate exercise program during pregnancy on the maternal health perception. Methods. A randomised controlled trial was performed. 101 primiparous women were allocated into the control group (CG, n=51 and the exercise group (EG, n=50, lost to follow-up 13, 11.4%. Women on the EC were asked to participate in a supervised exercise program during from 10-14 to 36 weeks of gestation (70-75 sessions, 55-60 min/session, three times per week. Women in the CG received usual care. All women were asked to fill in validated questionnaires about health perception and urinary incontinence before and after the intervention. Results. At the end of the intervention there were statistically significant differences between groups on health perception [very good: EG 35, 70% vs. CG 5, 9.8%; good: EG 15, 30% vs. CG 16, 31%; average EG 0, 0.0% vs. CG 26, 51%; poor EG 0, 0.0% vs. CG 3, 5.9%; very poor: EG 0, 0.0% vs. CG 1, 2% (p<.001]. What is more, women in the EG showed less urinary incontinence [ICIQ-SF Score EG 0.30 (SD1.3 vs. CG 3.1 (SD4.1, p<.001]. Conclusions. A supervised physical exercise program during pregnancy which includes pelvic floor muscle training, improves health perception and it is effective on primary prevention of urinary incontinence.

  5. Cerebellar supervised learning revisited: biophysical modeling and degrees-of-freedom control.

    Science.gov (United States)

    Kawato, Mitsuo; Kuroda, Shinya; Schweighofer, Nicolas

    2011-10-01

    The biophysical models of spike-timing-dependent plasticity have explored dynamics with molecular basis for such computational concepts as coincidence detection, synaptic eligibility trace, and Hebbian learning. They overall support different learning algorithms in different brain areas, especially supervised learning in the cerebellum. Because a single spine is physically very small, chemical reactions at it are essentially stochastic, and thus sensitivity-longevity dilemma exists in the synaptic memory. Here, the cascade of excitable and bistable dynamics is proposed to overcome this difficulty. All kinds of learning algorithms in different brain regions confront with difficult generalization problems. For resolution of this issue, the control of the degrees-of-freedom can be realized by changing synchronicity of neural firing. Especially, for cerebellar supervised learning, the triangle closed-loop circuit consisting of Purkinje cells, the inferior olive nucleus, and the cerebellar nucleus is proposed as a circuit to optimally control synchronous firing and degrees-of-freedom in learning. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. An Industrial Control System for the Supervision of the CERN Electrical Distribution Network

    CERN Document Server

    Poulsen, S

    1999-01-01

    CERN operates a large distribution network for the supply of electricity to the particle accelerators, experiments and the associated infrastructure. The distribution network operates on voltage levels from 400 V to 400 kV with a total yearly consumption of near to 1000 GWh. In the past, the laboratory has developed an in-house control system for this network, using the technologies applied to the accelerator control system. However, CERN is now working on a project to purchase, configure and install an industrial Electrical Network Supervisor (ENS). This is a state-of-the-art industrial control system completely developed and supported by an external contractor. The system - based on a scalable and distributed architecture - will allow the installation to be performed gradually, and will be tested while the existing system is fully operational. Ultimately, the complete electrical distribution network will be supervised with this new system, the maintenance and further development of which will be the complet...

  7. Kollegial supervision

    DEFF Research Database (Denmark)

    Andersen, Ole Dibbern; Petersson, Erling

    Publikationen belyser, hvordan kollegial supervision i en kan organiseres i en uddannelsesinstitution......Publikationen belyser, hvordan kollegial supervision i en kan organiseres i en uddannelsesinstitution...

  8. Stability Constraints for Robust Model Predictive Control

    Directory of Open Access Journals (Sweden)

    Amanda G. S. Ottoni

    2015-01-01

    Full Text Available This paper proposes an approach for the robust stabilization of systems controlled by MPC strategies. Uncertain SISO linear systems with box-bounded parametric uncertainties are considered. The proposed approach delivers some constraints on the control inputs which impose sufficient conditions for the convergence of the system output. These stability constraints can be included in the set of constraints dealt with by existing MPC design strategies, in this way leading to the “robustification” of the MPC.

  9. Can electronic stability control replace studded tyres?

    DEFF Research Database (Denmark)

    Elvik, Rune

    2015-01-01

    Highlights • Electronic stability control can substitute studded tyres. • This makes it easier to discourage the use of studded tyres. • A certain level of use of studded tyres makes roads less slippery.......Highlights • Electronic stability control can substitute studded tyres. • This makes it easier to discourage the use of studded tyres. • A certain level of use of studded tyres makes roads less slippery....

  10. Controllability and stabilization of parabolic equations

    CERN Document Server

    Barbu, Viorel

    2018-01-01

    This monograph presents controllability and stabilization methods in control theory that solve parabolic boundary value problems. Starting from foundational questions on Carleman inequalities for linear parabolic equations, the author addresses the controllability of parabolic equations on a variety of domains and the spectral decomposition technique for representing them. This method is, in fact, designed for use in a wider class of parabolic systems that include the heat and diffusion equations. Later chapters develop another process that employs stabilizing feedback controllers with a finite number of unstable modes, with special attention given to its use in the boundary stabilization of Navier–Stokes equations for the motion of viscous fluid. In turn, these applied methods are used to explore related topics like the exact controllability of stochastic parabolic equations with linear multiplicative noise. Intended for graduate students and researchers working on control problems involving nonlinear diff...

  11. OPTIMAL CONTROL FOR ELECTRIC VEHICLE STABILIZATION

    Directory of Open Access Journals (Sweden)

    MARIAN GAICEANU

    2016-01-01

    Full Text Available This main objective of the paper is to stabilize an electric vehicle in optimal manner to a step lane change maneuver. To define the mathematical model of the vehicle, the rigid body moving on a plane is taken into account. An optimal lane keeping controller delivers the adequate angles in order to stabilize the vehicle’s trajectory in an optimal way. Two degree of freedom linear bicycle model is adopted as vehicle model, consisting of lateral and yaw motion equations. The proposed control maintains the lateral stability by taking the feedback information from the vehicle transducers. In this way only the lateral vehicle’s dynamics are enough to considerate. Based on the obtained linear mathematical model the quadratic optimal control is designed in order to maintain the lateral stability of the electric vehicle. The numerical simulation results demonstrate the feasibility of the proposed solution.

  12. THE BANKING SUPERVISION: CAN IT REDUCE THE RISK-TAKING AND, CONSEQUENTLY, STRENGTHEN THE STABILITY OF THE BANKING SECTOR IN MOLDOVA?

    Directory of Open Access Journals (Sweden)

    Elena MARGARINT

    2015-12-01

    Full Text Available Actuality: The empirical studies on the impact of the supervision on the stability of the banking sector are mitigated, varying depending on the particular characteristics of the bank and, in addition, the country's policy in which banks operate. This is why this study is important for the banking sector in Moldova. Purpose: The objective of this article is to studies the effects of the banking supervision on the risk-taking of banks and, consequently, the stability of the banking sector in Moldova. Methods: To order to achieve its purpose, the author applied the method of static panel data with random effect. Results: This empirical analysis reported the following results: increased restrictions on the activities of banks increases the stability of the banking sector. On the other hand, the power and independence of the supervisory authority have a negative impact on the stability of Moldovan banks. The increase of the capital level strengthens the stability of Moldovan banks and, at the same time, reduces the risk. Thus, capital regulations are an important pillar of the policy of the regulation of the banking sector of Moldova.

  13. Virtual sensors for advanced vehicle stability control

    NARCIS (Netherlands)

    Leenen, R.; Schouten, H.

    2010-01-01

    Advanced vehicle control technologies provide a great potential to further improve vehicle handling, ride and safety. The goal of this research is to demonstrate the added value of the TNO Vehicle State Estimation module to integrated active safety. State-of-the-art Electronic Stability Control

  14. Stability of digital feedback control systems

    Directory of Open Access Journals (Sweden)

    Larkin Eugene

    2018-01-01

    Lag time characteristics are used for investigation of stability of linear systems. Digital PID controller is divided onto linear part, which is realized with a soft and pure lag unit, which is realized with both hardware and software. With use notions amplitude and phase margins, condition for stability of system functioning are obtained. Theoretical results are confirm with computer experiment carried out on the third-order system.

  15. Cost benefit analysis of instrumentation, supervision and control systems for nuclear power plants

    International Nuclear Information System (INIS)

    Hagen, P.

    1973-08-01

    A cost benefit analysis is carried out on a BWR type reactor power plant in which an on-line computer performs plant supervision, reporting, logging, calibration and control functions, using display devices and plotters, while an off-line computer is available for bigger jobs such as fuel management calculations. All on-line functions are briefly described and specified. Three types of computer system are considered, a simplex system, a dual computer system and a multi-processor system. These systems are analysed with respect to reliability, back-up instrumentation requirements and costs. While the multiprocessor system gave in all cases the lowest annual failure costs, the margin to the duplex system was so small that hardware, maintenance and software costs would play an important role in making a decision. (JIW)

  16. Observability and Decision Support for Supervision of Distributed Power System Control

    DEFF Research Database (Denmark)

    Pertl, Michael

    in NorthernCalifornia. Two possible applications of the model are presented: peak reduction compared to uncontrolled charging, and an energy arbitrage scenario. Overall, it is shown that a combination of classical and innovative approaches can contribute to improved situation awareness of control room...... operational information, relevant to the current grid condition, need to be developed. This dissertation covers three areas where specific challenges for improved observability and decision support in future control rooms are addressed: Classical large power system stability issues, innovative data......-network-based approach for real-time voltage estimation in active distribution grids, and a modeling approach to harness the flexibility of an aggregation of electric vehicles. For improved monitoring and maintaining power system stability, a decision support tool for transient stability preventive control, based...

  17. Balancing Inverted Pendulum by Angle Sensing Using Fuzzy Logic Supervised PID Controller Optimized by Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Ashutosh K. AGARWAL

    2011-10-01

    Full Text Available Genetic algorithms are robust search techniques based on the principles of evolution. A genetic algorithm maintains a population of encoded solutions and guides the population towards the optimum solution. This important property of genetic algorithm is used in this paper to stabilize the Inverted pendulum system. This paper highlights the application and stability of inverted pendulum using PID controller with fuzzy logic genetic algorithm supervisor . There are a large number of well established search techniques in use within the information technology industry. We propose a method to control inverted pendulum steady state error and overshoot using genetic algorithm technique.

  18. Effect of health education combining diet and exercise supervision in Chinese women with perimenopausal symptoms: a randomized controlled trial.

    Science.gov (United States)

    Xi, S; Mao, L; Chen, X; Bai, W

    2017-04-01

    This study aimed to evaluate the effect of health education combining diet and exercise supervision on menopausal symptoms and diet/exercise habits. The randomized controlled study enrolled 60 patients with perimenopausal syndrome (Kupperman Menopause Index (KMI) score ≥15). The participants were randomized into either an intervention group (n = 30) or a control group (n = 30). Women were interviewed with questionnaires about perimenopausal symptoms, diet pattern and exercise habit. Their height and weight were measured. Women in the intervention group received health education, diet supervision and exercise supervision twice a week while those in the control group continued as normal. The total KMI score, scores of individual symptoms, diet pattern and exercise habit were measured after intervention. The total KMI score, the individual KMI scores for paresthesia, irritability, depression/suspicious, fatigue, arthralgia/myalgia, and palpitations of the intervention group were significantly lower compared with the control group after intervention. The intake of cereal, meat, fats and oils of the intervention group were significantly lower at week 12 compared with baseline. The percentage of women with a regular exercise habit was significantly higher in the intervention group than in the control group after intervention. Twelve weeks intervention of health education combining diet and exercise supervision could improve perimenopausal symptoms and help the patients establish good living habits.

  19. MASCOT - MATLAB Stability and Control Toolbox

    Science.gov (United States)

    Kenny, Sean; Crespo, Luis

    2011-01-01

    MASCOT software was created to provide the conceptual aircraft designer accurate predictions of air vehicle stability and control characteristics. The code takes as input mass property data in the form of an inertia tensor, aerodynamic loading data, and propulsion (i.e. thrust) loading data. Using fundamental non-linear equations of motion, MASCOT then calculates vehicle trim and static stability data for any desired flight condition. Common predefined flight conditions are included. The predefined flight conditions include six horizontal and six landing rotation conditions with varying options for engine out, crosswind and sideslip, plus three takeoff rotation conditions. Results are displayed through a unique graphical interface developed to provide stability and control information to the conceptual design engineers using a qualitative scale indicating whether the vehicle has acceptable, marginal, or unacceptable static stability characteristics. This software allows the user to prescribe the vehicle s CG location, mass, and inertia tensor so that any loading configuration between empty weight and maximum take-off weight can be analyzed. The required geometric and aerodynamic data as well as mass and inertia properties may be entered directly, passed through data files, or come from external programs such as Vehicle Sketch Pad (VSP). The current version of MASCOT has been tested with VSP used to compute the required data, which is then passed directly into the program. In VSP, the vehicle geometry is created and manipulated. The aerodynamic coefficients, stability and control derivatives, are calculated using VorLax, which is now available directly within VSP. MASCOT has been written exclusively using the technical computing language MATLAB . This innovation is able to bridge the gap between low-fidelity conceptual design and higher-fidelity stability and control analysis. This new tool enables the conceptual design engineer to include detailed static stability

  20. Observability and Decision Support for Supervision of Distributed Power System Control

    DEFF Research Database (Denmark)

    Pertl, Michael

    approach for real-time voltage estimation in active distribution grids, and a modeling approach to harness the flexibility of an aggregation of electric vehicles. For improved monitoring and maintaining power system stability, a decision support tool for transient stability preventive control, based...... stability margin is presented. The approach delivers a near optimal solution in terms of cost minimization due to its sequential nature and shows to be robust when applied to larger power systems. The general problem of low distribution grid observability is addressed by proposing a data-driven approach...... results in additional demand for charging which will require large investments in power distribution, transmission, and generation. However, this demand is often also flexible in time and can be actively managed to reduce the required investments and to enhance power system operation. Harnessing...

  1. Spheromak tilting and its stability control

    International Nuclear Information System (INIS)

    Hayashi, T.; Sato, T.

    1983-01-01

    Spheromak tilting instability was studied. A numerical technique to create a rather arbitrarily-shaped spheromak like the one with a flux hole was investigated. The dynamics governing the tilting instability, namely, the influence of the magnetic index, the toroidal current (q-profile) and the resistivity upon the tilting growth rate, and the roles of magnetc reconnection upon the nonlinear development were studied. The best way to control the tilting instability was invented. The stabilizing effects of the vertical wall, the isolated conducting cylindrical belt, and the horizontal wall were studied. Central pole stabilization was also investigated. The influence of the wall condition, namely, whether the wall acted as a flux conserver in the spheromak creation stage or not is discussed. The present study has shown that the three- dimensional simulation is indeed useful and practical in not only studying the underlying physics but also finding a stabilization technique of spheromaks. (Kato, T.)

  2. Integrating supervision, control and data acquisition—The ITER Neutral Beam Test Facility experience

    Energy Technology Data Exchange (ETDEWEB)

    Luchetta, A., E-mail: adriano.luchetta@igi.cnr.it; Manduchi, G.; Taliercio, C.; Breda, M.; Capobianco, R.; Molon, F.; Moressa, M.; Simionato, P.; Zampiva, E.

    2016-11-15

    Highlights: • The paper describes the experience gained in the integration of different systems for the control and data acquisition system of the ITER Neutral Beam Test Facility. • It describes the way the different frameworks have been integrated. • It reports some lessons learnt during system integration. • It reports some authors’ considerations about the development the ITER CODAC. - Abstract: The ITER Neutral Beam (NBI) Test Facility, under construction in Padova, Italy consists in the ITER full scale ion source for the heating neutral beam injector, referred to as SPIDER, and the full size prototype injector, referred to as MITICA. The Control and Data Acquisition System (CODAS) for SPIDER has been developed and is going to be in operation in 2016. The system is composed of four main components: Supervision, Slow Control, Fast Control and Data Acquisition. These components interact with each other to carry out the system operation and, since they represent a common pattern in fusion experiments, software frameworks have been used for each (set of) component. In order to reuse as far as possible the architecture developed for SPIDER, it is important to clearly define the boundaries and the interfaces among the system components so that the implementation of any component can be replaced without affecting the overall architecture. This work reports the experience gained in the development of SPIDER components, highlighting the importance in the definition of generic interfaces among component, showing how the specific solutions have been adapted to such interfaces and suggesting possible approaches for the development of other ITER subsystems.

  3. Integrating supervision, control and data acquisition—The ITER Neutral Beam Test Facility experience

    International Nuclear Information System (INIS)

    Luchetta, A.; Manduchi, G.; Taliercio, C.; Breda, M.; Capobianco, R.; Molon, F.; Moressa, M.; Simionato, P.; Zampiva, E.

    2016-01-01

    Highlights: • The paper describes the experience gained in the integration of different systems for the control and data acquisition system of the ITER Neutral Beam Test Facility. • It describes the way the different frameworks have been integrated. • It reports some lessons learnt during system integration. • It reports some authors’ considerations about the development the ITER CODAC. - Abstract: The ITER Neutral Beam (NBI) Test Facility, under construction in Padova, Italy consists in the ITER full scale ion source for the heating neutral beam injector, referred to as SPIDER, and the full size prototype injector, referred to as MITICA. The Control and Data Acquisition System (CODAS) for SPIDER has been developed and is going to be in operation in 2016. The system is composed of four main components: Supervision, Slow Control, Fast Control and Data Acquisition. These components interact with each other to carry out the system operation and, since they represent a common pattern in fusion experiments, software frameworks have been used for each (set of) component. In order to reuse as far as possible the architecture developed for SPIDER, it is important to clearly define the boundaries and the interfaces among the system components so that the implementation of any component can be replaced without affecting the overall architecture. This work reports the experience gained in the development of SPIDER components, highlighting the importance in the definition of generic interfaces among component, showing how the specific solutions have been adapted to such interfaces and suggesting possible approaches for the development of other ITER subsystems.

  4. Thermal equilibrium, stability and burn control

    International Nuclear Information System (INIS)

    Cohn, D.

    1982-01-01

    A number of aspects of the thermal stability and equilibrium control of ignited tokamak plasma have been investigated. Examined approaches were passive control (the effect of radial motion, the effect of radial motion and small additional transport loss), active control (the compression and decompression of plasma, subignited operation with small amount of variable external heating, and density control), and thermal equilibrium control (additional power loss from impurity radiation and enhanced transport from increased ripple). One-D calculation has been made on thermal instability eigen-modes. It was found that for electron thermal induction loss given by Alcator scaling and for neoclassical ion transport, there was at most one unstable mode with a temperature profile which maintains the temperature profile at thermal equilibrium. The effect of the coupling of temperature fluctuation and the fluctuation in major radius was investigated. Temperature driven radial motion combined with a small amount of ripple transport loss was found to be a very effective mechanism for passive thermal stability control. (Kato, T.)

  5. Improvements in stabilizing control at Black Mountain

    International Nuclear Information System (INIS)

    Twidle, T.R.; Engelbrecht, P.C.; Koel, J.W.S.

    1986-01-01

    The process flows of the three flotation circuits at the concentrator of the Black Mountain Mineral Development Company (Pty) Ltd are described. Because of the complexity of the circuits and the associated reagent regime, the plant is equipped with a comprehensive range of control equipment. The different process-control strategies are discussed, and the modifications that have been necessary to the stabilizing control loops in the copper, lead, and zinc flotation circuits are shown in detail. It is concluded that the control strategies have continued to bring about benefits and improvements to the process. X-ray fluorescence analysis was employed in the control process. Data is also given on the accuracy of the technique

  6. Does training frequency and supervision affect compliance, performance and muscular health? A cluster randomized controlled trial.

    Science.gov (United States)

    Dalager, Tina; Bredahl, Thomas G V; Pedersen, Mogens T; Boyle, Eleanor; Andersen, Lars L; Sjøgaard, Gisela

    2015-10-01

    The aim was to determine the effect of one weekly hour of specific strength training within working hours, performed with the same total training volume but with different training frequencies and durations, or with different levels of supervision, on compliance, muscle health and performance, behavior and work performance. In total, 573 office workers were cluster-randomized to: 1 WS: one 60-min supervised session/week, 3 WS: three 20-min supervised sessions/week, 9 WS: nine 7-min supervised sessions/week, 3 MS: three 20-min sessions/week with minimal supervision, or REF: a reference group without training. Outcomes were diary-based compliance, total training volume, muscle performance and questionnaire-based health, behavior and work performance. Comparisons were made among the WS training groups and between 3 WS and 3 MS. If no difference, training groups were collapsed (TG) and compared with REF. Results demonstrated similar degrees of compliance, mean(range) of 39(33-44)%, and total training volume, 13.266(11.977-15.096)kg. Musculoskeletal pain in neck and shoulders were reduced with approx. 50% in TG, which was significant compared with REF. Only the training groups improved significantly their muscle strength 8(4-13)% and endurance 27(12-37)%, both being significant compared with REF. No change in workability, productivity or self-rated health was demonstrated. Secondary analysis showed exercise self-efficacy to be a significant predictor of compliance. Regardless of training schedule and supervision, similar degrees of compliance were shown together with reduced musculoskeletal pain and improved muscle performance. These findings provide evidence that a great degree of flexibility is legitimate for companies in planning future implementation of physical exercise programs at the workplace. ClinicalTrials.gov, number NCT01027390. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Fuzzy control. Fundamentals, stability and design of fuzzy controllers

    Energy Technology Data Exchange (ETDEWEB)

    Michels, K. [Fichtner GmbH und Co. KG, Stuttgart (Germany); Klawonn, F. [Fachhochschule Braunschweig/Wolfenbuettel (Germany). Fachbereich Informatik; Kruse, R. [Magdeburg Univ. (Germany). Fakultaet Informatik, Abt. Wiss.- und Sprachverarbeitung; Nuernberger, A. (eds.) [California Univ., Berkeley, CA (United States). Computer Science Division

    2006-07-01

    The book provides a critical discussion of fuzzy controllers from the perspective of classical control theory. Special emphases are placed on topics that are of importance for industrial applications, like (self-) tuning of fuzzy controllers, optimisation and stability analysis. The book is written as a textbook for graduate students as well as a comprehensive reference book about fuzzy control for researchers and application engineers. Starting with a detailed introduction to fuzzy systems and control theory the reader is guided to up-to-date research results. (orig.)

  8. Computerized supervision and control system for movement at the RP-10 reactor control rods bank

    International Nuclear Information System (INIS)

    Padilla M, C.E.

    1998-01-01

    The project involves the use of a compatible microcomputer, Labwindows/CVI software, as well as National Instruments data acquisition cards AT-MIO16-E10 and PC-DIO96 to modify the sequence of movement of the reactor's rods and control them from a graphic interface in a computer's monitor. This graphic presentation is set as console of virtual instruments from where rod movement can be conducted. Normal rod movement, bank rod movement, and rod calibration have been considered. These experiences involve different logic of rod movements, which will determine movement sequence. Control of the automatic range of a current amplifier module was also considered. This module is know as 'automatic pilot amplifier' and given the strategic location of its detector (compensated ionizing camera) at the reactor's core, it delivers neutron flux current considered as reference to superficial neutron flux distribution at the reactor's core. Lecture and monitoring of this signal allows taking the reactor to a certain power, current of this signal is proportional to the power we want the reactor to reach. Advantages obtained with this system include the update of the control console, more uniform distribution of neutron flux, with lower and uniform burnup of nuclear fuel. (author)

  9. Supervised Learning

    Science.gov (United States)

    Rokach, Lior; Maimon, Oded

    This chapter summarizes the fundamental aspects of supervised methods. The chapter provides an overview of concepts from various interrelated fields used in subsequent chapters. It presents basic definitions and arguments from the supervised machine learning literature and considers various issues, such as performance evaluation techniques and challenges for data mining tasks.

  10. Are qualitative and quantitative sleep problems associated with delinquency when controlling for psychopathic features and parental supervision?

    Science.gov (United States)

    Backman, Heidi; Laajasalo, Taina; Saukkonen, Suvi; Salmi, Venla; Kivivuori, Janne; Aronen, Eeva T

    2015-10-01

    The aim of this study was to explore the relationship between sleep, including both qualitative and quantitative aspects, and delinquent behaviour while controlling for psychopathic features of adolescents and parental supervision at bedtime. We analysed data from a nationally representative sample of 4855 Finnish adolescents (mean age 15.3 years, 51% females). Sleep problems, hours of sleep and delinquency were evaluated via self-report. Psychopathic features were measured with the Antisocial Process Screening Device - Self-Report. In negative binomial regressions, gender and sleep-related variables acted as predictors for both property and violent crime after controlling for psychopathic features and parental supervision at bedtime. The results suggest that both sleep problems (at least three times per week, at least for a year) and an insufficient amount of sleep (less than 7 h) are associated with property crime and violent behaviour, and the relationship is not explained by gender, degree of parental supervision at bedtime or co-occurring psychopathic features. These results suggest that sleep difficulties and insufficient amount of sleep are associated with delinquent behaviour in adolescents. The significance of addressing sleep-related problems, both qualitative and quantitative, among adolescents is thus highlighted. Implications for a prevention technique of delinquent behaviour are discussed. © 2015 European Sleep Research Society.

  11. Whither Supervision?

    OpenAIRE

    Duncan Waite

    2006-01-01

    This paper inquires if the school supervision is in decadence. Dr. Waite responds that the answer will depend on which perspective you look at it. Dr. Waite suggests taking in consideration three elements that are related: the field itself, the expert in the field (the professor, the theorist, the student and the administrator), and the context. When these three elements are revised, it emphasizes that there is not a consensus about the field of supervision, but there are coincidences related...

  12. Modernization of supervision and control central store of the Cabril RBMA; Modernizacion de la supervision y el control del almacen centralizado de RBMA El Cabril

    Energy Technology Data Exchange (ETDEWEB)

    Arribas de la Fuente, M.; Mena, V.; Navarro Santos, M.

    2012-07-01

    The modernization of the control room Cabril through the use of new technology has allowed the unification of control and monitoring of all systems of the center, giving the Cabril greater versatility and ease of development operations the plant, as well as enabling the expansion and continuous improvement is promoting the installation from the beginning of its activity.

  13. STUDY ABOUT THE STABILITY AND CONTROL OF A ROTOR AIRPLANE

    OpenAIRE

    Stafy, Victor; Neto, Aristeu Silveira

    2017-01-01

    On this paper is studied the stability and control of a Rotor Airplane, more specifically a MAV (Micro Air Vehicle) and how works the dynamics of flight of this unusual configuration of aircraft. It’s discussed the impact of the gyroscopic effect on stability (mainly lateral and directional stability) and was found the best feasible configuration of the stability surface, but the project of the stabilizers was limited to lifting surfaces that use airfoil sections, the possibility of a very un...

  14. Passivity-Based Control for Two-Wheeled Robot Stabilization

    Science.gov (United States)

    Uddin, Nur; Aryo Nugroho, Teguh; Agung Pramudito, Wahyu

    2018-04-01

    A passivity-based control system design for two-wheeled robot (TWR) stabilization is presented. A TWR is a statically-unstable non-linear system. A control system is applied to actively stabilize the TWR. Passivity-based control method is applied to design the control system. The design results in a state feedback control law that makes the TWR closed loop system globally asymptotically stable (GAS). The GAS is proven mathematically. The TWR stabilization is demonstrated through computer simulation. The simulation results show that the designed control system is able to stabilize the TWR.

  15. Automatic learning rate adjustment for self-supervising autonomous robot control

    Science.gov (United States)

    Arras, Michael K.; Protzel, Peter W.; Palumbo, Daniel L.

    1992-01-01

    Described is an application in which an Artificial Neural Network (ANN) controls the positioning of a robot arm with five degrees of freedom by using visual feedback provided by two cameras. This application and the specific ANN model, local liner maps, are based on the work of Ritter, Martinetz, and Schulten. We extended their approach by generating a filtered, average positioning error from the continuous camera feedback and by coupling the learning rate to this error. When the network learns to position the arm, the positioning error decreases and so does the learning rate until the system stabilizes at a minimum error and learning rate. This abolishes the need for a predetermined cooling schedule. The automatic cooling procedure results in a closed loop control with no distinction between a learning phase and a production phase. If the positioning error suddenly starts to increase due to an internal failure such as a broken joint, or an environmental change such as a camera moving, the learning rate increases accordingly. Thus, learning is automatically activated and the network adapts to the new condition after which the error decreases again and learning is 'shut off'. The automatic cooling is therefore a prerequisite for the autonomy and the fault tolerance of the system.

  16. Optimal control theory applied to fusion plasma thermal stabilization

    International Nuclear Information System (INIS)

    Sager, G.; Miley, G.; Maya, I.

    1985-01-01

    Many authors have investigated stability characteristics and performance of various burn control schemes. The work presented here represents the first application of optimal control theory to the problem of fusion plasma thermal stabilization. The objectives of this initial investigation were to develop analysis methods, demonstrate tractability, and present some preliminary results of optimal control theory in burn control research

  17. LHC beam stability and feedback control

    Energy Technology Data Exchange (ETDEWEB)

    Steinhagen, Ralph

    2007-07-20

    This report presents the stability and the control of the Large Hadron Collider's (LHC) two beam orbits and their particle momenta using beam-based feedback systems. The aim of this report is to contribute to a safe and reliable LHC commissioning and machine operation. The first part of the analysis gives an estimate of the expected sources of orbit and energy perturbations that can be grouped into environmental sources, machine-inherent sources and machine element failures: the slowest perturbation due to ground motion, tides, temperature fluctuations of the tunnel and other environmental influences are described in this report by a propagation model that is both qualitatively and quantitatively supported by geophone and beam motion measurements at LEP and other CERN accelerators. The second part of this analysis deals with the control of the two LHC beams' orbit and energy through automated feedback systems. Based on the reading of the more than 1056 beam position monitors (BPMs) that are distributed over the machine, a central global feedback controller calculates new deflection strengths for the more than 1060 orbit corrector magnets (CODs) that are suitable to correct the orbit and momentum around their references. this report provides an analysis of the BPMs and CODs involved in the orbit and energy feedback. The BPMs are based on a wide-band time normaliser circuit that converts the transverse beam position reading of each individual particle bunch into two laser pulses that are separated by a time delay and transmitted through optical fibres to an acquisition card that converts the delay signals into a digital position. A simple error model has been tested and compared to the measurement accuracy of LHC type BPMs, obtained through beam-based measurements in the SPS. The average beam position is controlled through 1060 superconducting and individually powered corrector dipole magnets. The proposed correction in 'time-domain' consists of a

  18. LHC beam stability and feedback control

    International Nuclear Information System (INIS)

    Steinhagen, Ralph

    2007-01-01

    This report presents the stability and the control of the Large Hadron Collider's (LHC) two beam orbits and their particle momenta using beam-based feedback systems. The aim of this report is to contribute to a safe and reliable LHC commissioning and machine operation. The first part of the analysis gives an estimate of the expected sources of orbit and energy perturbations that can be grouped into environmental sources, machine-inherent sources and machine element failures: the slowest perturbation due to ground motion, tides, temperature fluctuations of the tunnel and other environmental influences are described in this report by a propagation model that is both qualitatively and quantitatively supported by geophone and beam motion measurements at LEP and other CERN accelerators. The second part of this analysis deals with the control of the two LHC beams' orbit and energy through automated feedback systems. Based on the reading of the more than 1056 beam position monitors (BPMs) that are distributed over the machine, a central global feedback controller calculates new deflection strengths for the more than 1060 orbit corrector magnets (CODs) that are suitable to correct the orbit and momentum around their references. this report provides an analysis of the BPMs and CODs involved in the orbit and energy feedback. The BPMs are based on a wide-band time normaliser circuit that converts the transverse beam position reading of each individual particle bunch into two laser pulses that are separated by a time delay and transmitted through optical fibres to an acquisition card that converts the delay signals into a digital position. A simple error model has been tested and compared to the measurement accuracy of LHC type BPMs, obtained through beam-based measurements in the SPS. The average beam position is controlled through 1060 superconducting and individually powered corrector dipole magnets. The proposed correction in 'time-domain' consists of a proportional

  19. Supervised pelvic floor muscle training versus attention-control massage treatment in patients with faecal incontinence

    DEFF Research Database (Denmark)

    Ussing, Anja; Dahn, Inge; Due, Ulla

    2017-01-01

    supplements is recommended as first-line treatment for faecal incontinence. Despite this, the effect of pelvic floor muscle training for faecal incontinence is unclear. No previous trials have investigated the efficacy of supervised pelvic floor muscle training in combination with conservative treatment...... treatment and conservative treatment. The primary outcome is participants' rating of symptom changes after 16 weeks of treatment using the Patient Global Impression of Improvement Scale. Secondary outcomes are the Vaizey Incontinence Score, the Fecal Incontinence Severity Index, the Fecal Incontinence...

  20. Uganda; Financial System Stability Assessment, including Reports on the Observance of Standards and Codes on the following topics: Monetary and Financial Policy Transparency, Banking Supervision, Securities Regulation, and Payment Systems

    OpenAIRE

    International Monetary Fund

    2003-01-01

    This paper presents findings of Uganda’s Financial System Stability Assessment, including Reports on the Observance of Standards and Codes on Monetary and Financial Policy Transparency, Banking Supervision, Securities Regulation, Insurance Regulation, Corporate Governance, and Payment Systems. The banking system in Uganda, which dominates the financial system, is fundamentally sound, more resilient than in the past, and currently poses no threat to macroeconomic stability. A major disruption ...

  1. Efficacy of supervised exercise combined with transcutaneous electrical nerve stimulation in women with fibromyalgia: a prospective controlled study.

    Science.gov (United States)

    Mutlu, B; Paker, N; Bugdayci, D; Tekdos, D; Kesiktas, N

    2013-03-01

    The aim of this study was to investigate the results of a supervised exercise with transcutaneous electrical nerve stimulation (TENS) in an exercise controlled study in women with fibromyalgia. Sixty-six women with fibromyalgia who admitted to the outpatient clinic of our hospital were randomized into two treatment groups. The patients in both groups participated in a supervised combined exercise program for 12 weeks. The women in first group had additional TENS in the first 3 weeks of the study. All subjects were analyzed at the baseline, at the end of the 3rd and 12th weeks. Outcome measures were tender point count (TPC), myalgic pain score (MPS), Fibromyalgia Impact Questionnaire (FIQ) and Short Form-36 (SF-36) Health Survey. Sixty women with fibromyalgia completed the study. The patients in both groups showed improvement in terms of TPC, MPS, FIQ, physical and mental summary scores and total scores of SF-36 at the end of the 3rd and 12th weeks. The improvement in MPS at the third week was higher in the first group (p = 0.01). But there was no difference in terms of the improvement in MPS between the groups at the end of the 12th week control (p = 0.87). There was no significant difference between the improvement in the other outcome parameters of the two groups. As a result, supervised exercise program was successful to improve the myalgic pain, functional status and quality of life in women with fibromyalgia. Exercises combined with TENS might be useful due to quick myalgic pain relief in the treatment of fibromyalgia in everyday practice.

  2. Nonlinear stability control and λ-bifurcation

    International Nuclear Information System (INIS)

    Erneux, T.; Reiss, E.L.; Magnan, J.F.; Jayakumar, P.K.

    1987-01-01

    Passive techniques for nonlinear stability control are presented for a model of fluidelastic instability. They employ the phenomena of λ-bifurcation and a generalization of it. λ-bifurcation occurs when a branch of flutter solutions bifurcates supercritically from a basic solution and terminates with an infinite period orbit at a branch of divergence solutions which bifurcates subcritically from the basic solution. The shape of the bifurcation diagram then resembles the greek letter λ. When the system parameters are in the range where flutter occurs by λ-bifurcation, then as the flow velocity increase the flutter amplitude also increases, but the frequencies of the oscillations decrease to zero. This diminishes the damaging effects of structural fatigue by flutter, and permits the flow speed to exceed the critical flutter speed. If generalized λ-bifurcation occurs, then there is a jump transition from the flutter states to a divergence state with a substantially smaller amplitude, when the flow speed is sufficiently larger than the critical flutter speed

  3. Whither Supervision?

    Directory of Open Access Journals (Sweden)

    Duncan Waite

    2006-11-01

    Full Text Available This paper inquires if the school supervision is in decadence. Dr. Waite responds that the answer will depend on which perspective you look at it. Dr. Waite suggests taking in consideration three elements that are related: the field itself, the expert in the field (the professor, the theorist, the student and the administrator, and the context. When these three elements are revised, it emphasizes that there is not a consensus about the field of supervision, but there are coincidences related to its importance and that it is related to the improvement of the practice of the students in the school for their benefit. Dr. Waite suggests that the practice on this field is not always in harmony with what the theorists affirm. When referring to the supervisor or the skilled person, the author indicates that his or her perspective depends on his or her epistemological believes or in the way he or she conceives the learning; that is why supervision can be understood in different ways. About the context, Waite suggests that there have to be taken in consideration the social or external forces that influent the people and the society, because through them the education is affected. Dr. Waite concludes that the way to understand the supervision depends on the performer’s perspective. He responds to the initial question saying that the supervision authorities, the knowledge on this field, the performers, and its practice, are maybe spread but not extinct because the supervision will always be part of the great enterprise that we called education.

  4. Stabilization of model-based networked control systems

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, Francisco [CIDMA, Universidade de Aveiro, Aveiro (Portugal); Instituto Politécnico de Viana do Castelo, Viana do Castelo (Portugal); Abreu, Carlos [Instituto Politécnico de Viana do Castelo, Viana do Castelo (Portugal); CMEMS-UMINHO, Universidade do Minho, Braga (Portugal); Mendes, Paulo M. [CMEMS-UMINHO, Universidade do Minho, Braga (Portugal)

    2016-06-08

    A class of networked control systems called Model-Based Networked Control Systems (MB-NCSs) is considered. Stabilization of MB-NCSs is studied using feedback controls and simulation of stabilization for different feedbacks is made with the purpose to reduce the network trafic. The feedback control input is applied in a compensated model of the plant that approximates the plant dynamics and stabilizes the plant even under slow network conditions. Conditions for global exponential stabilizability and for the choosing of a feedback control input for a given constant time between the information moments of the network are derived. An optimal control problem to obtain an optimal feedback control is also presented.

  5. New tools for the stability control

    International Nuclear Information System (INIS)

    Melera, J.; Albendea, M.; Escriva, A.; Munoz-Cobos, L. L.; Montesinos

    2006-01-01

    IBERDROLA INGENIERIA y CONSTRUCCION, IBERDROLA GENERACION and the polytechnical Univisty of Valencia, are carrying out a project of R and D called DROP (Decay Ratio on-line Predictor) whose objective is to create a tool (predictor and monitor) for on-line monitoring of the thermal-hydraulic stability during the operation of BWR reactors. DROP is intended to be integrated in CAPRICOPE; the Core Monitoring System of Cofrentes NPP, to allow supervisors to known stability margins during the operation, simplifying reactor start-up and shutdown. In transient conditions, the knowledge of reactor stability will avoid reactor unplanned shutdowns. (Author) 11 refs

  6. Intelligent multivariate process supervision

    International Nuclear Information System (INIS)

    Visuri, Pertti.

    1986-01-01

    This thesis addresses the difficulties encountered in managing large amounts of data in supervisory control of complex systems. Some previous alarm and disturbance analysis concepts are reviewed and a method for improving the supervision of complex systems is presented. The method, called multivariate supervision, is based on adding low level intelligence to the process control system. By using several measured variables linked together by means of deductive logic, the system can take into account the overall state of the supervised system. Thus, it can present to the operators fewer messages with higher information content than the conventional control systems which are based on independent processing of each variable. In addition, the multivariate method contains a special information presentation concept for improving the man-machine interface. (author)

  7. Emissions Control in Swirl-Stabilized Combustors

    National Research Council Canada - National Science Library

    Hanson, Ronald K

    2006-01-01

    ...) fabricate a swirl-stabilized gas and liquid fuel burner with optical access to enable diagnostic development that mimics the atmospheric pressure performance of the University of Cincinnati facility, and 4...

  8. Computation of stabilizing PI and PID controllers using the stability boundary locus

    International Nuclear Information System (INIS)

    Tan, Nusret; Kaya, Ibrahim; Yeroglu, Celaleddin; Atherton, Derek P.

    2006-01-01

    In this paper, a new method for the calculation of all stabilizing PI controllers is given. The proposed method is based on plotting the stability boundary locus in the (k p , k i )-plane and then computing the stabilizing values of the parameters of a PI controller. The technique presented does not require sweeping over the parameters and also does not need linear programming to solve a set of inequalities. Thus it offers several important advantages over existing results obtained in this direction. Beyond stabilization, the method is used to shift all poles to a shifted half plane that guarantees a specified settling time of response. Computation of stabilizing PI controllers which achieve user specified gain and phase margins is studied. It is shown via an example that the stabilizing region in the (k p , k i )-plane is not always a convex set. The proposed method is also used to design PID controllers. The limiting values of a PID controller which stabilize a given system are obtained in the (k p , k i )-plane (k p , k d )-plane and (k i , k d )-plane. Furthermore, the proposed method is used to compute all the parameters of a PI controller which stabilize a control system with an interval plant family. Examples are given to show the benefits of the method presented

  9. Computation of robustly stabilizing PID controllers for interval systems.

    Science.gov (United States)

    Matušů, Radek; Prokop, Roman

    2016-01-01

    The paper is focused on the computation of all possible robustly stabilizing Proportional-Integral-Derivative (PID) controllers for plants with interval uncertainty. The main idea of the proposed method is based on Tan's (et al.) technique for calculation of (nominally) stabilizing PI and PID controllers or robustly stabilizing PI controllers by means of plotting the stability boundary locus in either P-I plane or P-I-D space. Refinement of the existing method by consideration of 16 segment plants instead of 16 Kharitonov plants provides an elegant and efficient tool for finding all robustly stabilizing PID controllers for an interval system. The validity and relatively effortless application of presented theoretical concepts are demonstrated through a computation and simulation example in which the uncertain mathematical model of an experimental oblique wing aircraft is robustly stabilized.

  10. Computerised training improves cognitive performance in chronic pain: a participant-blinded randomised active-controlled trial with remote supervision.

    Science.gov (United States)

    Baker, Katharine S; Georgiou-Karistianis, Nellie; Lampit, Amit; Valenzuela, Michael; Gibson, Stephen J; Giummarra, Melita J

    2018-04-01

    Chronic pain is associated with reduced efficiency of cognitive performance, and few studies have investigated methods of remediation. We trialled a computerised cognitive training protocol to determine whether it could attenuate cognitive difficulties in a chronic pain sample. Thirty-nine adults with chronic pain (mean age = 43.3, 61.5% females) were randomised to an 8-week online course (3 sessions/week from home) of game-like cognitive training exercises, or an active control involving watching documentary videos. Participants received weekly supervision by video call. Primary outcomes were a global neurocognitive composite (tests of attention, speed, and executive function) and self-reported cognition. Secondary outcomes were pain (intensity; interference), mood symptoms (depression; anxiety), and coping with pain (catastrophising; self-efficacy). Thirty participants (15 training and 15 control) completed the trial. Mixed model intention-to-treat analyses revealed significant effects of training on the global neurocognitive composite (net effect size [ES] = 0.43, P = 0.017), driven by improved executive function performance (attention switching and working memory). The control group reported improvement in pain intensity (net ES = 0.65, P = 0.022). Both groups reported subjective improvements in cognition (ES = 0.28, P = 0.033) and catastrophising (ES = 0.55, P = 0.006). Depression, anxiety, self-efficacy, and pain interference showed no change in either group. This study provides preliminary evidence that supervised cognitive training may be a viable method for enhancing cognitive skills in persons with chronic pain, but transfer to functional and clinical outcomes remains to be demonstrated. Active control results suggest that activities perceived as relaxing or enjoyable contribute to improved perception of well-being. Weekly contact was pivotal to successful program completion.

  11. Asymptotic stability of a genetic network under impulsive control

    International Nuclear Information System (INIS)

    Li Fangfei; Sun Jitao

    2010-01-01

    The study of the stability of genetic network is an important motif for the understanding of the living organism at both molecular and cellular levels. In this Letter, we provide a theoretical method for analyzing the asymptotic stability of a genetic network under impulsive control. And the sufficient conditions of its asymptotic stability under impulsive control are obtained. Finally, an example is given to illustrate the effectiveness of the obtained method.

  12. Power system stabilizers based on modern control techniques

    Energy Technology Data Exchange (ETDEWEB)

    Malik, O P; Chen, G P; Zhang, Y; El-Metwally, K [Calgary Univ., AB (Canada). Dept. of Electrical and Computer Engineering

    1994-12-31

    Developments in digital technology have made it feasible to develop and implement improved controllers based on sophisticated control techniques. Power system stabilizers based on adaptive control, fuzzy logic and artificial networks are being developed. Each of these control techniques possesses unique features and strengths. In this paper, the relative performance of power systems stabilizers based on adaptive control, fuzzy logic and neural network, both in simulation studies and real time tests on a physical model of a power system, is presented and compared to that of a fixed parameter conventional power system stabilizer. (author) 16 refs., 45 figs., 3 tabs.

  13. Stabilization of Networked Control Systems Under Feedback-based Communication

    National Research Council Canada - National Science Library

    Zhang, Lei; Hristu-Varsakelis, Dimitrios

    2004-01-01

    We study the stabilization of a networked control system (NSC) in which multiple sensors and actuators of a physical plant share a communication medium to exchange information with a remote controller...

  14. Supervision and control of grid connected PV-Storage systems with the five level diode clamped inverter

    International Nuclear Information System (INIS)

    Himour, Kamal; Ghedamsi, Kaci; Berkouk, El Madjid

    2014-01-01

    Highlights: • Use of battery bank in grid connection photovoltaic system to ensure the energetic autonomy of the system. • Improve the quality of energy by the use of five-level inverter in a grid connection PV generation system. • Control of inverter by fast and simplified space vector pulse width modulation. • Control and supervision of active and reactive power in the grid. - Abstract: This paper aimed to evaluate the use of photovoltaic-battery storage systems to supply electric power in the distribution grid through a multilevel inverter. The proposed system is composed by four PV generators with MPPT (P and O) control, four battery storage systems connected to each capacitor of the DC link and a five level diode clamped inverter connected to the grid by a traditional three phase transformer. The proposed control has a hierarchical structure with both a grid side control level to regulate the power and the current injected to the grid and four input side regulation units. The system operator controls the power production of the four PV generators by sending out reference power signals to each input side regulation unit, the input side regulation units regulate the voltage of each capacitor of the DC link, regulate the voltage and the state of charge of each battery storage system

  15. Supervised learning from human performance at the computationally hard problem of optimal traffic signal control on a network of junctions.

    Science.gov (United States)

    Box, Simon

    2014-12-01

    Optimal switching of traffic lights on a network of junctions is a computationally intractable problem. In this research, road traffic networks containing signallized junctions are simulated. A computer game interface is used to enable a human 'player' to control the traffic light settings on the junctions within the simulation. A supervised learning approach, based on simple neural network classifiers can be used to capture human player's strategies in the game and thus develop a human-trained machine control (HuTMaC) system that approaches human levels of performance. Experiments conducted within the simulation compare the performance of HuTMaC to two well-established traffic-responsive control systems that are widely deployed in the developed world and also to a temporal difference learning-based control method. In all experiments, HuTMaC outperforms the other control methods in terms of average delay and variance over delay. The conclusion is that these results add weight to the suggestion that HuTMaC may be a viable alternative, or supplemental method, to approximate optimization for some practical engineering control problems where the optimal strategy is computationally intractable.

  16. Authorization procedure for the construction and operation of nuclear installations within the EC Member States, including supervision and control

    International Nuclear Information System (INIS)

    Amaducci, Sandro; Didier, J.M.

    1978-01-01

    This report is an updating of the report EUR 5284, Authorization procedure for the construction and operation of nuclear installations within the EEC Member States, prepared in 1974 by J.M. Didier and Associates. Recent developments regarding the authorization procedure for the construction and operation of nuclear installations have taken place in Italy (introduction of a site approval procedure) and in Denmark (adoption of an overall legislation on the subject, however not yet in force). With respect to supervision and control of nuclear installations during construction and operation, competences of, as well as their exercise by, supervisory authorities in all EC Member States, with the exception of Ireland, are also analysed in the current study

  17. Statutory Instrument No 276 of 1994. European Communities (Supervision and control of certain shipments of radioactive waste) Regulations, 1994

    International Nuclear Information System (INIS)

    1994-09-01

    These Regulations provide for the implementation of Council Directive 92/3/EURATOM of 3 February, 1992 laying down conditions for the supervision and control of shipments of radioactive waste between Member States and into and out of the Community, whenever quantities and concentrations of such waste exceed certain levels. These conditions supplement the existing Council Directives on basic safety standards for the health protection of workers and the general public against the dangers of ionising radiation. The Radiological Protection Institute of Ireland has been deemed the Competent Authority for the purpose of implementation of these Regulations in this country and application should be made to that body for all authorisations required under the Regulations

  18. Coaxial jets stability and control possibility

    Czech Academy of Sciences Publication Activity Database

    Trávníček, Zdeněk; Hrubý, Jan; Vogel, Jiří

    2005-01-01

    Roč. 4, - (2005), s. 121-130. ISBN 83-89334-82-8 R&D Projects: GA AV ČR(CZ) IAA2076203 Institutional research plan: CEZ:AV0Z20760514 Keywords : jets * stability * visualization Subject RIV: BK - Fluid Dynamics

  19. Supervision and control system for greenhouses using wireless network sensors; Sistema de supervisao e controle para casas de vegetacao empregando rede 'wireless' de sensores

    Energy Technology Data Exchange (ETDEWEB)

    Fontes, Ivo Reis; Cagnon, Jose Angelo; Rodrigues, Ricardo Martini [Universidade Estadual Paulista (UNESP), Bauru, SP (Brazil). Fac. de Engenharia. Dept. de Engenharia Eletrica], e-mail: ivo@feb.unesp.br, e-mail: martini@feb.unesp.br, e-mail: jacagnon@feb.unesp.br

    2004-07-01

    The present work had as objective the configuration of a supervision and control system for greenhouses applications using a system of data collection of control parameters through a wireless communication network. In agreement with the adopted methodology, its development was accomplished in three different phases. Initially the hardware modules for a Sensors Unit, a Data Concentrator Unit and a capacitive type soil moisture sensor were developed. Soon afterwards an application was configured through a SCADA supervision and control program, the Ellipse PRO, dedicated to the supervision and control of a green house. In the final phase the necessary data were collected for the training of an artificial neural network that is integral part of the humidity sensor. The Sensors Unit and the Data Concentrator Unit were developed starting from microcontrollers of low consumption and high performance and presents excellent cost/benefit relationship. These units are used in the acquisition and data storage of in comings from several sensors applied in the installation. In order to eliminate the inconveniences of a system that uses nets of electric cables connections links of RF was used, with pattern of message of the protocol MODBUS/RTU, for the communication among these units. The application developed through the Ellipse FOR is composed of a group of screens that represents in a virtual way the complete green house environment. Through these screens the operator can alter the operation state of each one of the elements involved in the irrigation and climatization control process. According the cost characteristics, operation flexibility and existent functionality this system represents a solution economically viable in the automation green houses. It can be affirmed that this configuration represents an innovative solution and that can contribute in much for the improvement of cultivated species as well as to provide the necessary ways for the rational use of the

  20. A user-friendly, digital console for the control room parameters supervision in old-generation nuclear plants

    International Nuclear Information System (INIS)

    Memmi, Fabrizio; Falconi, Luca; Cappelli, Mauro; Palomba, Mario; Sepielli, Massimo

    2016-01-01

    Highlights: • We propose a user-friendly monitoring system for reactor supervision. • Statistics from data analysis can be used to optimize reactor management. • The tool has been designed in order to include a simulation tool for prediction. • The proposed system could help operators in training and continuous learning. - Abstract: In this work a user-friendly, digital monitoring system for supervision of process variables coming from a fission nuclear reactor of TRIGA type (1-MW TRIGA reactor RC-1) is presented. The system, developed on the basis of COTS tools, can easily interface the control room instrumentation and display the typical monitoring parameters (e.g. nuclear power, temperatures, flow rates, radiological variables) in an intuitive, user-adjustable way for plant operators. A front panel of a virtual instrument allows for a direct measure while the acquisition system, for signals coming from the reactor, can process the data and generate a detailed representation of the results, whose statistics can be interpreted to optimize the reactor management parameters. This system has been also designed so as to include a simulation tool able to predict specific performances and investigate critical phenomena, and to optimize overall plant performances. In particular, it allows to have a feedback control and to perform several predictive statistical surveys of all main process parameters. The proposed system could help operators in training and continuous learning activities, and serve as a basis for an advanced decision support system and for a remote training tool for students and trainees not authorized to work in a radiation environment.

  1. A user-friendly, digital console for the control room parameters supervision in old-generation nuclear plants

    Energy Technology Data Exchange (ETDEWEB)

    Memmi, Fabrizio; Falconi, Luca; Cappelli, Mauro, E-mail: mauro.cappelli@enea.it; Palomba, Mario; Sepielli, Massimo

    2016-06-15

    Highlights: • We propose a user-friendly monitoring system for reactor supervision. • Statistics from data analysis can be used to optimize reactor management. • The tool has been designed in order to include a simulation tool for prediction. • The proposed system could help operators in training and continuous learning. - Abstract: In this work a user-friendly, digital monitoring system for supervision of process variables coming from a fission nuclear reactor of TRIGA type (1-MW TRIGA reactor RC-1) is presented. The system, developed on the basis of COTS tools, can easily interface the control room instrumentation and display the typical monitoring parameters (e.g. nuclear power, temperatures, flow rates, radiological variables) in an intuitive, user-adjustable way for plant operators. A front panel of a virtual instrument allows for a direct measure while the acquisition system, for signals coming from the reactor, can process the data and generate a detailed representation of the results, whose statistics can be interpreted to optimize the reactor management parameters. This system has been also designed so as to include a simulation tool able to predict specific performances and investigate critical phenomena, and to optimize overall plant performances. In particular, it allows to have a feedback control and to perform several predictive statistical surveys of all main process parameters. The proposed system could help operators in training and continuous learning activities, and serve as a basis for an advanced decision support system and for a remote training tool for students and trainees not authorized to work in a radiation environment.

  2. Supervised pelvic floor muscle training versus attention-control massage treatment in patients with faecal incontinence: Statistical analysis plan for a randomised controlled trial.

    Science.gov (United States)

    Ussing, Anja; Dahn, Inge; Due, Ulla; Sørensen, Michael; Petersen, Janne; Bandholm, Thomas

    2017-12-01

    Faecal incontinence affects approximately 8-9% of the adult population. The condition is surrounded by taboo; it can have a devastating impact on quality of life and lead to major limitations in daily life. Pelvic floor muscle training in combination with information and fibre supplements is recommended as first-line treatment for faecal incontinence. Despite this, the effect of pelvic floor muscle training for faecal incontinence is unclear. No previous trials have investigated the efficacy of supervised pelvic floor muscle training in combination with conservative treatment and compared this to an attention-control massage treatment including conservative treatment. The aim of this trial is to investigate if 16 weeks of supervised pelvic floor muscle training in combination with conservative treatment is superior to attention-control massage treatment and conservative treatment in patients with faecal incontinence. Randomised, controlled, superiority trial with two parallel arms. 100 participants with faecal incontinence will be randomised to either (1) individually supervised pelvic floor muscle training and conservative treatment or (2) attention-control massage treatment and conservative treatment. The primary outcome is participants' rating of symptom changes after 16 weeks of treatment using the Patient Global Impression of Improvement Scale. Secondary outcomes are the Vaizey Incontinence Score, the Fecal Incontinence Severity Index, the Fecal Incontinence Quality of Life Scale, a 14-day bowel diary, anorectal manometry and rectal capacity measurements. Follow-up assessment at 36 months will be conducted. This paper describes and discusses the rationale, the methods and in particular the statistical analysis plan of this trial.

  3. Man-machine supervision

    International Nuclear Information System (INIS)

    Montmain, J.

    2005-01-01

    Today's complexity of systems where man is involved has led to the development of more and more sophisticated information processing systems where decision making has become more and more difficult. The operator task has moved from operation to supervision and the production tool has become indissociable from its numerical instrumentation and control system. The integration of more and more numerous and sophisticated control indicators in the control room does not necessary fulfill the expectations of the operation team. It is preferable to develop cooperative information systems which are real situation understanding aids. The stake is not the automation of operators' cognitive tasks but the supply of a reasoning help. One of the challenges of interactive information systems is the selection, organisation and dynamical display of information. The efficiency of the whole man-machine system depends on the communication interface efficiency. This article presents the principles and specificities of man-machine supervision systems: 1 - principle: operator's role in control room, operator and automation, monitoring and diagnosis, characteristics of useful models for supervision; 2 - qualitative reasoning: origin, trends, evolutions; 3 - causal reasoning: causality, causal graph representation, causal and diagnostic graph; 4 - multi-points of view reasoning: multi flow modeling method, Sagace method; 5 - approximate reasoning: the symbolic numerical interface, the multi-criteria decision; 6 - example of application: supervision in a spent-fuel reprocessing facility. (J.S.)

  4. The algebraic criteria for the stability of control systems

    Science.gov (United States)

    Cremer, H.; Effertz, F. H.

    1986-01-01

    This paper critically examines the standard algebraic criteria for the stability of linear control systems and their proofs, reveals important previously unnoticed connections, and presents new representations. Algebraic stability criteria have also acquired significance for stability studies of non-linear differential equation systems by the Krylov-Bogoljubov-Magnus Method, and allow realization conditions to be determined for classes of broken rational functions as frequency characteristics of electrical network.

  5. Angle Stability Analysis for Voltage-Controlled Converters

    DEFF Research Database (Denmark)

    Lin, Hengwei; Jia, Chenxi; Guerrero, Josep M.

    2017-01-01

    a criterion to analyze the quasi-steady angle stability and the direct current (DC) side stability for VSCs. The operating limit and the angle instability mechanism are revealed, which is generally applicable to the voltage-controlled converters. During the analysis, the influence of the parameters on angle...... stability is studied. Further, the difference on instability mechanism between power electronic converters and synchronous generators are explained in detail. Finally, experiment results with corrective actions verify the analysis....

  6. A robust nonlinear stabilizer as a controller for improving transient stability in micro-grids.

    Science.gov (United States)

    Azimi, Seyed Mohammad; Afsharnia, Saeed

    2017-01-01

    This paper proposes a parametric-Lyapunov approach to the design of a stabilizer aimed at improving the transient stability of micro-grids (MGs). This strategy is applied to electronically-interfaced distributed resources (EI-DRs) operating with a unified control configuration applicable to all operational modes (i.e. grid-connected mode, islanded mode, and mode transitions). The proposed approach employs a simple structure compared with other nonlinear controllers, allowing ready implementation of the stabilizer. A new parametric-Lyapunov function is proposed rendering the proposed stabilizer more effective in damping system transition transients. The robustness of the proposed stabilizer is also verified based on both time-domain simulations and mathematical proofs, and an ultimate bound has been derived for the frequency transition transients. The proposed stabilizer operates by deploying solely local information and there are no needs for communication links. The deteriorating effects of the primary resource delays on the transient stability are also treated analytically. Finally, the effectiveness of the proposed stabilizer is evaluated through time-domain simulations and compared with the recently-developed stabilizers performed on a multi-resource MG. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  7. Stabilization with guaranteed safety using Control Lyapunov–Barrier Function

    NARCIS (Netherlands)

    Romdlony, Muhammad Zakiyullah; Jayawardhana, Bayu

    2016-01-01

    We propose a novel nonlinear control method for solving the problem of stabilization with guaranteed safety for nonlinear systems. The design is based on the merging of the well-known Control Lyapunov Function (CLF) and the recent concept of Control Barrier Function (CBF). The proposed control

  8. BANKING SUPERVISION IN EUROPEAN UNION

    OpenAIRE

    Lavinia Mihaela GUȚU; Vasile ILIE

    2013-01-01

    The need for prudential supervision imposed to banks by law arises from the action that banking market’s basic factors have. Therefore, it is about banks’ role in economy. The normal functioning of banks in all their important duties maintains the stability of banking system. Further, the stability of the entire economy depends on the stability of the banking system. Under conditions of imbalance regarding treasury or liquidity, banks are faced with unmanageable crisis and the consequences ca...

  9. Effects of supervised exercise on lipid profiles and blood pressure control in people with type 2 diabetes mellitus: a meta-analysis of randomized controlled trials.

    Science.gov (United States)

    Hayashino, Yasuaki; Jackson, Jeffrey L; Fukumori, Norio; Nakamura, Fumiaki; Fukuhara, Shunichi

    2012-12-01

    Our study's purpose was to perform a systematic review to assess the effect of supervised exercise interventions on lipid profiles and blood pressure control. We searched electronic databases and selected studies that evaluated the effect of supervised exercise intervention on cardiovascular risk factors in adult people with type 2 diabetes. We used random effect models to derive weighted mean differences of exercise on lipid profiles and blood pressure control. Forty-two RCTs (2808 subjects) met inclusion criteria and are included in our meta-analysis. Structured exercise was associated with a change in systolic blood pressure (SBP) of -2.42 mmHg (95% CI, -4.39 to -0.45 mmHg), diastolic blood pressure (DBP) of -2.23 mmHg (95% CI, -3.21 to -1.25 mmHg), high-density lipoprotein cholesterol (HDL-C) of 0.04 mmol/L (95% CI, 0.02-0.07 mmol/L), and low-density lipoprotein cholesterol (LDL-C) of -0.16 mmol/L (95% CI, -0.30 to -0.01 mmol/L). Heterogeneity was partially explained by age, dietary co-intervention and the duration and intensity of the exercise. Supervised exercise is effective in improving blood pressure control, lowering LDL-C, and elevating HDL-C levels in people with diabetes. Physicians should recommend exercise for their adult patients with diabetes who can safely do so. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  10. Robust Stabilization of Nonlinear Systems with Uncertain Varying Control Coefficient

    Directory of Open Access Journals (Sweden)

    Zaiyue Yang

    2014-01-01

    Full Text Available This paper investigates the stabilization problem for a class of nonlinear systems, whose control coefficient is uncertain and varies continuously in value and sign. The study emphasizes the development of a robust control that consists of a modified Nussbaum function to tackle the uncertain varying control coefficient. By such a method, the finite-time escape phenomenon has been prevented when the control coefficient is crossing zero and varying its sign. The proposed control guarantees the asymptotic stabilization of the system and boundedness of all closed-loop signals. The control performance is illustrated by a numerical simulation.

  11. Stabilization and trajectory tracking control for underactuated

    Indian Academy of Sciences (India)

    The control of quadrotor helicopter has been a great challenge for control engineers and researchers since quadrotor is an underactuated and a highly unstable nonlinear system. In this paper, the dynamic model of quadrotor has been derived and a so-called robust optimal backstepping control (ROBC) is designed to ...

  12. Model predictive control of hybrid systems : stability and robustness

    NARCIS (Netherlands)

    Lazar, M.

    2006-01-01

    This thesis considers the stabilization and the robust stabilization of certain classes of hybrid systems using model predictive control. Hybrid systems represent a broad class of dynamical systems in which discrete behavior (usually described by a finite state machine) and continuous behavior

  13. Fault Tolerant Control: A Simultaneous Stabilization Result

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Blondel, V.D.

    2004-01-01

    This paper discusses the problem of designing fault tolerant compensators that stabilize a given system both in the nominal situation, as well as in the situation where one of the sensors or one of the actuators has failed. It is shown that such compensators always exist, provided that the system...... is detectable from each output and that it is stabilizable. The proof of this result is constructive, and a worked example shows how to design a fault tolerant compensator for a simple, yet challeging system. A family of second order systems is described that requires fault tolerant compensators of arbitrarily...

  14. The Moderating Role of Non-Controlling Supervision and Organizational Learning Culture on Employee Creativity: The Influences of Domain Expertise and Creative Personality

    Science.gov (United States)

    Jeong, Shinhee; McLean, Gary N.; McLean, Laird D.; Yoo, Sangok; Bartlett, Kenneth

    2017-01-01

    Purpose: By adopting a multilevel approach, this paper aims to examine the relationships among employee creativity and creative personality, domain expertise (i.e. individual-level factors), non-controlling supervision style and organizational learning culture (i.e. team-level factors). It also investigates the cross-level interactions between…

  15. Modernization of supervision and control central store of the Cabril RBMA

    International Nuclear Information System (INIS)

    Arribas de la Fuente, M.; Mena, V.; Navarro Santos, M.

    2012-01-01

    The modernization of the control room Cabril through the use of new technology has allowed the unification of control and monitoring of all systems of the center, giving the Cabril greater versatility and ease of development operations the plant, as well as enabling the expansion and continuous improvement is promoting the installation from the beginning of its activity.

  16. In-line instrumentation and computer-controlled process supervision in reprocessing

    International Nuclear Information System (INIS)

    Mache, H.R.; Groll, P.

    Measuring equipment is needed for continuous monitoring of concentration in radioactive process solutions. A review is given of existing in-line apparatus and of computer-controlled data processing. A process control system is described for TAMARA, a model extraction facility for the U/HNO 3 /TBP system

  17. Advances in power system modelling, control and stability analysis

    CERN Document Server

    Milano, Federico

    2016-01-01

    Advances in Power System Modelling, Control and Stability Analysis captures the variety of new methodologies and technologies that are changing the way modern electric power systems are modelled, simulated and operated.

  18. Knee joint stabilization therapy in patients with osteoarthritis of the knee: a randomized, controlled trial.

    Science.gov (United States)

    Knoop, J; Dekker, J; van der Leeden, M; van der Esch, M; Thorstensson, C A; Gerritsen, M; Voorneman, R E; Peter, W F; de Rooij, M; Romviel, S; Lems, W F; Roorda, L D; Steultjens, M P M

    2013-08-01

    To investigate whether an exercise program, initially focusing on knee stabilization and subsequently on muscle strength and performance of daily activities is more effective than an exercise program focusing on muscle strength and performance of daily activities only, in reducing activity limitations in patients with knee osteoarthritis (OA) and instability of the knee joint. A single-blind, randomized, controlled trial involving 159 knee OA patients with self-reported and/or biomechanically assessed knee instability, randomly assigned to two treatment groups. Both groups received a supervised exercise program for 12 weeks, consisting of muscle strengthening exercises and training of daily activities, but only in the experimental group specific knee joint stabilization training was provided. Outcome measures included activity limitations (Western Ontario and McMaster Universities Osteoarthritis Index - WOMAC physical function, primary outcome), pain, global perceived effect and knee stability. Both treatment groups demonstrated large (∼20-40%) and clinically relevant reductions in activity limitations, pain and knee instability, which were sustained 6 months post-treatment. No differences in effectiveness between experimental and control treatment were found on WOMAC physical function (B (95% confidence interval - CI) = -0.01 (-2.58 to 2.57)) or secondary outcome measures, except for a higher global perceived effect in the experimental group (P = 0.04). Both exercise programs were highly effective in reducing activity limitations and pain and restoring knee stability in knee OA patients with instability of the knee. In knee OA patients suffering from knee instability, specific knee joint stabilization training, in addition to muscle strengthening and functional exercises, does not seem to have any additional value. Dutch Trial Register (NTR) registration number: NTR1475. Copyright © 2013 Osteoarthritis Research Society International. Published by Elsevier

  19. Stability of position control system in JIPP T-II

    International Nuclear Information System (INIS)

    Sakurai, Keiichi; Tanahashi, Shygo

    1980-01-01

    Computations and experiments on the stability of a feedback control system for maintaining a plasma column in equilibrium are described. The time response of the displacement of the plasma to the desired position is examined by solving the equation of motion of the plasma column. We show that the stability of the feedback control system is improved by using an additional term which represents the shift velocity of the plasma column. (author)

  20. Microgrid Stability Controller Based on Adaptive Robust Total SMC

    OpenAIRE

    Su, Xiaoling; Han, Minxiao; Guerrero, Josep M.; Sun, Hai

    2015-01-01

    This paper presents a microgrid stability controller (MSC) in order to provide existing distributed generation units (DGs) the additional functionality of working in islanding mode without changing their control strategies in grid-connected mode and to enhance the stability of the microgrid. Microgrid operating characteristics and mathematical models of the MSC indicate that the system is inherently nonlinear and time-variable. Therefore, this paper proposes an adaptive robust total sliding...

  1. Contributions to fuzzy polynomial techniques for stability analysis and control

    OpenAIRE

    Pitarch Pérez, José Luis

    2014-01-01

    The present thesis employs fuzzy-polynomial control techniques in order to improve the stability analysis and control of nonlinear systems. Initially, it reviews the more extended techniques in the field of Takagi-Sugeno fuzzy systems, such as the more relevant results about polynomial and fuzzy polynomial systems. The basic framework uses fuzzy polynomial models by Taylor series and sum-of-squares techniques (semidefinite programming) in order to obtain stability guarantees...

  2. Solar Dynamic Power System Stability Analysis and Control

    Science.gov (United States)

    Momoh, James A.; Wang, Yanchun

    1996-01-01

    The objective of this research is to conduct dynamic analysis, control design, and control performance test of solar power system. Solar power system consists of generation system and distribution network system. A bench mark system is used in this research, which includes a generator with excitation system and governor, an ac/dc converter, six DDCU's and forty-eight loads. A detailed model is used for modeling generator. Excitation system is represented by a third order model. DDCU is represented by a seventh order system. The load is modeled by the combination of constant power and constant impedance. Eigen-analysis and eigen-sensitivity analysis are used for system dynamic analysis. The effects of excitation system, governor, ac/dc converter control, and the type of load on system stability are discussed. In order to improve system transient stability, nonlinear ac/dc converter control is introduced. The direct linearization method is used for control design. The dynamic analysis results show that these controls affect system stability in different ways. The parameter coordination of controllers are recommended based on the dynamic analysis. It is concluded from the present studies that system stability is improved by the coordination of control parameters and the nonlinear ac/dc converter control stabilize system oscillation caused by the load change and system fault efficiently.

  3. A VME-based accumulation, control and supervising system for neutron texture measurements

    International Nuclear Information System (INIS)

    Kirilov, A.S.; Heinitz, J.; Korobchenko, M.L.; Rezaev, V.E.; Sirotin, A.P.

    1997-01-01

    Nowadays VME-based systems to control neutron measurement instruments are forcing out those built with PC and CAMAC. One of several alternative solutions is presented here. Its main feature is the implementation of the entire system on the VME site. Both the hardware and the software parts are considered. The instrument can be controlled locally or remotely via local network (even from PCs) with a modern-styled graphical user interface

  4. Research on Design of MUH Attitude Stability Augmentation Control System

    Science.gov (United States)

    Fan, Shigang

    2017-09-01

    Attitude stability augmentation control system with a lower cost need to be designed so that MUH (Mini Unmanned Helicopter) can adapt to different types of geographic environment and fly steadily although the weather may be bad. Attitude feedback was calculated mainly by filtering estimation within attitude acquisition module in this system. Stability augmentation can be improved mainly by PI. This paper will depict running principle and designing process of MUH attitude stability augmentation control system and algorithm that is considered as an important part in this system.

  5. Optimal boundary control and boundary stabilization of hyperbolic systems

    CERN Document Server

    Gugat, Martin

    2015-01-01

    This brief considers recent results on optimal control and stabilization of systems governed by hyperbolic partial differential equations, specifically those in which the control action takes place at the boundary.  The wave equation is used as a typical example of a linear system, through which the author explores initial boundary value problems, concepts of exact controllability, optimal exact control, and boundary stabilization.  Nonlinear systems are also covered, with the Korteweg-de Vries and Burgers Equations serving as standard examples.  To keep the presentation as accessible as possible, the author uses the case of a system with a state that is defined on a finite space interval, so that there are only two boundary points where the system can be controlled.  Graduate and post-graduate students as well as researchers in the field will find this to be an accessible introduction to problems of optimal control and stabilization.

  6. Stability analysis of embedded nonlinear predictor neural generalized predictive controller

    Directory of Open Access Journals (Sweden)

    Hesham F. Abdel Ghaffar

    2014-03-01

    Full Text Available Nonlinear Predictor-Neural Generalized Predictive Controller (NGPC is one of the most advanced control techniques that are used with severe nonlinear processes. In this paper, a hybrid solution from NGPC and Internal Model Principle (IMP is implemented to stabilize nonlinear, non-minimum phase, variable dead time processes under high disturbance values over wide range of operation. Also, the superiority of NGPC over linear predictive controllers, like GPC, is proved for severe nonlinear processes over wide range of operation. The necessary conditions required to stabilize NGPC is derived using Lyapunov stability analysis for nonlinear processes. The NGPC stability conditions and improvement in disturbance suppression are verified by both simulation using Duffing’s nonlinear equation and real-time using continuous stirred tank reactor. Up to our knowledge, the paper offers the first hardware embedded Neural GPC which has been utilized to verify NGPC–IMP improvement in realtime.

  7. Stability of DC Voltage Droop Controllers in VSC HVDC Systems

    DEFF Research Database (Denmark)

    Thams, Florian; Suul, Jon Are; D’Arco, Salvatore

    2015-01-01

    Future multi-terminal HVDC systems are expected to utilize dc voltage droop controllers and several control implementations have been proposed in literature. This paper first classifies possible dc droop implementations in a simple framework. Then, the small-signal stability of a VSC-based conver......Future multi-terminal HVDC systems are expected to utilize dc voltage droop controllers and several control implementations have been proposed in literature. This paper first classifies possible dc droop implementations in a simple framework. Then, the small-signal stability of a VSC...

  8. The technical supervision interface

    CERN Document Server

    Sollander, P

    1998-01-01

    The Technical Control Room (TCR) is currently using 30 different applications for the remote supervision of the technical infrastructure at CERN. These applications have all been developed with the CERN made Uniform Man Machine Interface (UMMI) tools built in 1990. However, the visualization technology has evolved phenomenally since 1990, the Technical Data Server (TDS) has radically changed our control system architecture, and the standardization and the maintenance of the UMMI applications have become important issues as their number increases. The Technical Supervision Interface is intended to replace the UMMI and solve the above problems. Using a standard WWW-browser for the display, it will be inherently multi-platform and hence available for control room operators, equipment specialists and on-call personnel.

  9. Spherical gyroscopic moment stabilizer for attitude control of microsatellites

    Science.gov (United States)

    Keshtkar, Sajjad; Moreno, Jaime A.; Kojima, Hirohisa; Uchiyama, Kenji; Nohmi, Masahiro; Takaya, Keisuke

    2018-02-01

    This paper presents a new and improved concept of recently proposed two-degrees of freedom spherical stabilizer for triaxial orientation of microsatellites. The analytical analysis of the advantages of the proposed mechanism over the existing inertial attitude control devices are introduced. The extended equations of motion of the stabilizing satellite including the spherical gyroscope, for control law design and numerical simulations, are studied in detail. A new control algorithm based on continuous high-order sliding mode algorithms, for managing the torque produced by the stabilizer and therefore the attitude control of the satellite in the presence of perturbations/uncertainties, is presented. Some numerical simulations are carried out to prove the performance of the proposed mechanism and control laws.

  10. Stabilizing device for control rod tip

    International Nuclear Information System (INIS)

    Verdone, G.F.

    1982-01-01

    A control rod has a spring device on its lower end for eliminating oscillatory contact of the rod against its adjacent guide tube wall. The base of the device is connected to the lower tip of the rod. A plurality of elongated extensions are cantilevered downward from the base. Each extension has a shoulder for contacting the guide tube, and the plurality of shoulders as a group has a transverse dimension that is preset to be larger than the inner diameter of the guide tube such that an interference fit is obtained when the control rod is inserted in the tube. The elongated extensions form an open-ended, substantially hollow member through which most of the liquid coolant flows, and the spaces between adjacent extensions allow the flow to bypass the shoulders without experiencing a significant pressure drop

  11. Hummingbirds control hovering flight by stabilizing visual motion.

    Science.gov (United States)

    Goller, Benjamin; Altshuler, Douglas L

    2014-12-23

    Relatively little is known about how sensory information is used for controlling flight in birds. A powerful method is to immerse an animal in a dynamic virtual reality environment to examine behavioral responses. Here, we investigated the role of vision during free-flight hovering in hummingbirds to determine how optic flow--image movement across the retina--is used to control body position. We filmed hummingbirds hovering in front of a projection screen with the prediction that projecting moving patterns would disrupt hovering stability but stationary patterns would allow the hummingbird to stabilize position. When hovering in the presence of moving gratings and spirals, hummingbirds lost positional stability and responded to the specific orientation of the moving visual stimulus. There was no loss of stability with stationary versions of the same stimulus patterns. When exposed to a single stimulus many times or to a weakened stimulus that combined a moving spiral with a stationary checkerboard, the response to looming motion declined. However, even minimal visual motion was sufficient to cause a loss of positional stability despite prominent stationary features. Collectively, these experiments demonstrate that hummingbirds control hovering position by stabilizing motions in their visual field. The high sensitivity and persistence of this disruptive response is surprising, given that the hummingbird brain is highly specialized for sensory processing and spatial mapping, providing other potential mechanisms for controlling position.

  12. Methods of supervision in the uranium industry; Les methodes de controle dans l'industrie de l'uranium

    Energy Technology Data Exchange (ETDEWEB)

    Prugnard, J [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1961-07-01

    In its broad sense the supervision applied to uranium refining is not appreciably different from that found in ordinary industry. It should be noted however that the main preoccupation will be exceptional purity in the final product, and constant vigilance must be directed towards conforming with the accepted safety standards in such an organisation. The various problems at issue and the steps taken to solve them will be discussed successively. (author) [French] L'aspect general du controle dans le raffinage de l'uranium ne differe pas sensiblement de celui que l'on peut rencontrer dans les industries classiques. Il conviendra cependant de remarquer que le souci dominant visera plus a l'obtention d'un produit final de purete exceptionnelle et qu'une vigilance de tous les instants sera necessaire pour respecter les normes de securite dans une telle entreprise. On etudiera successivement les divers objectifs a atteindre et l'organisation mise en oeuvre pour les realiser. (auteur)

  13. A fuzzy controller for the real time supervision of nuclear power reactors

    International Nuclear Information System (INIS)

    Si Fodil, M.; Guly, F.; Siarry, P.; Tyran, J.L.

    2000-01-01

    We describe the development of a real time fuzzy controller aimed at an adequate core axial power distribution inside a pressurized water reactor (PWR). The system has been implemented in simulation using the EDF model on Matlab-Simulink on a Sun workstation. Some experiments tests at different power levels have been performed: several low levels modeling falls in the network consumption and test modeling falls in the consumption followed by a recovery of the consumption. The results of all these experiments will be discussed. (orig.)

  14. Control and supervision of a time projection chamber with GEM readout

    International Nuclear Information System (INIS)

    Kaiser, David

    2014-01-01

    To get a deeper understanding of the structure of nucleons and the strong interaction binding the constituents inside, the CBELSA/TAPS experiment investigates the resonance spectrum of baryons by meson photoproduction within the scope of the SFB/TRR 16 ''Subnuclear Structure of Matter''. In order to support and expand the physical program, the existing Inner Detector will be replaced by a Time Projection Chamber (TPC) within the next few years. This allows for the detection of charged reaction channels, which can't be measured with the CBELSA/TAPS experiment up to now, as well as for particle identification from the specific energy loss. A First prototype with GEM foils for charge amplification in front of the readout plane and suitable size for the CBELSA/TAPS experiment was built in collaboration with the TU Munich, the detector laboratory of the GSI in Darmstadt and the Stefan-Meyer-Institute of the University Vienna. The TPC has been commissioned successfully within the FOPI experiment at the GSI during several test beam campaigns. Additionally, systematic studies have been carried out with a smaller Test-TPC using a TestBench providing an accurate external track definition. As the electron drift velocity in the TPC volume is a crucial parameter for the exact track reconstruction, detailed simulations of the drift velocity and its dependency on external parameters, such as drift voltage, pressure, gas flow or temperature, have been carried out. The results of these simulations recommend a constant monitoring of all examined parameters to allow a reasonable use of the simulated drift velocities. For this purpose, and to ensure a safe and stable operation of the TPCs and the other detectors on the TestBench, the required hardware, the control software based on a data base and a graphical user interface were designed and constructed as the main part of this work. With this so-called SlowControl, it was possible to measure, control and store several parameters - e

  15. Optical fiber sensors technology for supervision, control and protection of high power systems

    Science.gov (United States)

    Nascimento, Ivo Maciel

    etching. In this case, an excimer laser was used. Extremely thin fiber tips were obtained, with an ultra-high sensitivity to strain. The other technique employed to fabricate the fiber Bragg gratings was the point-by-point femtosecond laser inscription. In this case, the sensing elements are very stable at high temperatures and can be used to measure strain in harsh conditions. The employment of optical fiber lasers as sensing elements was also considered in this Thesis. Two laser cavities were studied, one based on the ring configuration and the other based on a figure-of-eight configuration. From these works, the quality of the laser emission, namely the signal-to-noise ratio, the reduced full-width at half maximum and the stability should be highlighted. These characteristics allowed the measurement of different physical parameters, such as strain, temperature and torsion. Lastly, the possibility to use microspheres as sensing elements was considered. Using the electric arc of a fusion splicer, it is possible to create microspheres at the tip of an optical fiber. Furthermore, with this technique it is chains of microspheres can be obtained, constituting Mach-Zehnder-type interferometers which are sensitive to physical parameters like strain and temperature. The preliminary results obtained by introducing silica microspheres in a support structure are also presented. In this case, the sensors were subjected to temperature variations. All the experimental work was combined with the respective theoretical considerations. Many questions have been raised with the course of this PhD, and there are still some without a definite answer. Thus, new research paths can be followed, having their basis grounded in the configurations here presented.

  16. BANKING SUPERVISION IN EUROPEAN UNION

    Directory of Open Access Journals (Sweden)

    Lavinia Mihaela GUȚU

    2013-10-01

    Full Text Available The need for prudential supervision imposed to banks by law arises from the action that banking market’s basic factors have. Therefore, it is about banks’ role in economy. The normal functioning of banks in all their important duties maintains the stability of banking system. Further, the stability of the entire economy depends on the stability of the banking system. Under conditions of imbalance regarding treasury or liquidity, banks are faced with unmanageable crisis and the consequences can be fatal. To ensure long-term stability of the banking system, supervisory regulations were constituted in order to prevent banks focusing on achieving rapidly high profits and protect the interests of depositors. Starting from this point, this paper will carry out a study on existing models of supervision in the European Union’s Member States. A comparison between them will support identifying the advantages and disadvantages of each of them.

  17. Stabilization of rotational motion with application to spacecraft attitude control

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    2000-01-01

    for global stabilization of a rotary motion. Along with a model of the system formulated in the Hamilton's canonical from the algorithm uses information about a required potential energy and a dissipation term. The control action is the sum of the gradient of the potential energy and the dissipation force......The objective of this paper is to develop a control scheme for stabilization of a hamiltonian system. The method generalizes the results available in the literature on motion control in the Euclidean space to an arbitrary differrential manifol equipped with a metric. This modification is essencial...... on a Riemannian manifold. The Lyapnov stability theory is adapted and reformulated to fit to the new framework of Riemannian manifolds. Toillustrate the results a spacecraft attitude control problem is considered. Firstly, a global canonical representation for the spacecraft motion is found, then three spacecraft...

  18. Stabilization of rotational motion with application to spacecraft attitude control

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    2001-01-01

    for global stabilization of a rotary motion. Along with a model of the system formulated in the Hamilton's canonical from the algorithm uses information about a required potential energy and a dissipation term. The control action is the sum of the gradient of the potential energy and the dissipation force......The objective of this paper is to develop a control scheme for stabilization of a hamiltonian system. The method generalizes the results available in the literature on motion control in the Euclidean space to an arbitrary differrential manifol equipped with a metric. This modification is essencial...... on a Riemannian manifold. The Lyapnov stability theory is adapted and reformulated to fit to the new framework of Riemannian manifolds. Toillustrate the results a spacecraft attitude control problem is considered. Firstly, a global canonical representation for the spacecraft motion is found, then three spacecraft...

  19. A Decision Support Tool for Transient Stability Preventive Control

    DEFF Research Database (Denmark)

    Pertl, Michael; Weckesser, Johannes Tilman Gabriel; Rezkalla, Michel M.N.

    2017-01-01

    The paper presents a decision support tool for transient stability preventive control contributing to increased situation awareness of control room operators by providing additional information about the state of the power system in terms of transient stability. A time-domain approach is used...... a predefined minimum critical clearing time for faults at all buses is proposed, while costs are minimized. The results of the assessment are presented to the control room operator, who decides to accept the suggested dispatch or to repeat the assessment considering additional user-specific constraints...

  20. Power system small signal stability analysis and control

    CERN Document Server

    Mondal, Debasish; Sengupta, Aparajita

    2014-01-01

    Power System Small Signal Stability Analysis and Control presents a detailed analysis of the problem of severe outages due to the sustained growth of small signal oscillations in modern interconnected power systems. The ever-expanding nature of power systems and the rapid upgrade to smart grid technologies call for the implementation of robust and optimal controls. Power systems that are forced to operate close to their stability limit have resulted in the use of control devices by utility companies to improve the performance of the transmission system against commonly occurring power system

  1. Implementation of the Control and supervision of ALICE ZDC positioning Systems- TWEEP-08

    CERN Document Server

    Swoboda, Detlef

    2008-01-01

    The ALICE Zero Degree Calorimeters (ZDC) have been installed to either side of the LHC IP2 in the machine tunnel next to the dipole magnet D2. The calorimeter modules are mounted on a special table equipped with a mechanism to lower the modules away from the beam orbit during injection and acceleration. During stable operation the modules can be raised individually to be aligned with the beam orbit. The horizontal clearance between ZDC modules and beam pipe will be only about 3 mm. Anti-collision switches are therefore installed to protect the beam pipes against accidental damage. The movement of the calorimeter modules and the protection switches are remote controlled by the ALICE ZDC positioning system.

  2. An active interferometer-stabilization scheme with linear phase control

    DEFF Research Database (Denmark)

    Andresen, Esben Ravn; Krishnamachari, v v; Potma, E O

    2006-01-01

    We report a simple and robust computer-based active interferometer stabilization scheme which does not require modulation of the interfering beams and relies on an error signal which is linearly related to the optical path difference. In this setup, a non-collinearly propagating reference laser...... beam stabilizes the interference output of the laser light propagating collinearly through the interferometer. This stabilization scheme enables adjustable phase control with 20 ms switching times in the range from 0.02π radians to 6π radians at 632.8 nm....

  3. Biomass Combustion Control and Stabilization Using Low-Cost Sensors

    Directory of Open Access Journals (Sweden)

    Ján Piteľ

    2013-01-01

    Full Text Available The paper describes methods for biomass combustion process control and burning stabilization based on low-cost sensing of carbon monoxide emissions and oxygen concentration in the flue gas. The designed control system was tested on medium-scale biomass-fired boilers and some results are evaluated and presented in the paper.

  4. Stability Analysis for Car Following Model Based on Control Theory

    International Nuclear Information System (INIS)

    Meng Xiang-Pei; Li Zhi-Peng; Ge Hong-Xia

    2014-01-01

    Stability analysis is one of the key issues in car-following theory. The stability analysis with Lyapunov function for the two velocity difference car-following model (for short, TVDM) is conducted and the control method to suppress traffic congestion is introduced. Numerical simulations are given and results are consistent with the theoretical analysis. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  5. Production Supervision Incorporated With Network Technology-A Solution For Controlling In-Process Inventory

    Directory of Open Access Journals (Sweden)

    Suraj Yadav

    2013-06-01

    Full Text Available In context to the manufacturing management in medium scale production floor, work-in-process (WIP management or the inprocess inventory and control as the inevitable result of the production process has become a vital link of production plan. Due to the growing production requirements and the potential economic benefits of manufacturing process flow, enterprises have been pushed to integrate work-in-process management with their manufacturing process and the larger the company the larger the list of in-process inventory and this all are typically hard to manage so for the same respect the author in this paper has lighted on the integration of sophisticated electronics and networking technologies with the W.I.P with an native and low cost solution for managing the same, specially for the medium scaled company dealing with large number of product or with the customized product with reference to study of present scenario of a multinational company’s plant engineering department.

  6. Control Design of a Nonlinear Controller to Stabilize the Nonlinear ...

    African Journals Online (AJOL)

    inyangs

    is used to formularize the delay differential equation in equation. (13), which accounts for the delayed terms in the system. By applying the Leibniz integration rule, the derivative. •. V shows that the system is asymptotically stable with a negative definite solution in equation (14). The conditions for the stability are: •. The delay ...

  7. Supervision in Firms

    OpenAIRE

    Vafaï , Kouroche

    2012-01-01

    URL des Documents de travail : http://centredeconomiesorbonne.univ-paris1.fr/bandeau-haut/documents-de-travail/; Documents de travail du Centre d'Economie de la Sorbonne 2012.84 - ISSN : 1955-611X; To control, evaluate, and motivate their agents, firms employ supervisors. As shown by empirical investigations, biased evaluation by supervisors linked to collusion is a persistent feature of firms. This paper studies how deceptive supervision affects agency relationships. We consider a three-leve...

  8. Power system stability enhancement using facts controllers: a review

    International Nuclear Information System (INIS)

    Abido, M. A

    2009-01-01

    In recent years, power demand has increased substantially while the expansion of power generation and transmission has been severely limited due to limited resources and environmental restrictions. As a consequence, some transmission lines are heavily loaded and the system stability becomes a power transfer-limiting factor. Flexible AC transmission systems (FACTS) controllers have been mainly used for solving various power system steady state control problems. However, recent studies reveal that FACTS controllers could be employed to enhance power system stability in addition to their main function of power flow control. The literature shows an increasing interest in this subject for the last two decades, where the enhancement of system stability using FACTS controllers has been extensively investigated. This paper presents a comprehensive review on the research and developments in the power system stability enhancement using FACTS damping controllers. Several technical issues related to FACTS installations have been highlighted and performance comparison of different FACTS controllers has been discussed. In addition, some of the utility experience, real-world installations, and semiconductor technology development have been reviewed and summarized. Applications of FACTS to other power system studies have also been discussed. About two hundred twenty seven research publications have been classified and appended for a quick reference. (author)

  9. Eco-geomorphic controls on slope stability

    Science.gov (United States)

    Hales, T.; Ford, C.; Hwang, T.; Vose, J.; Band, L.

    2009-04-01

    Vegetation controls soil-mantled landscape evolution primarily through growth of roots into soil and rock. Root-soil interactions affect the spatial distribution and rate of shallow landsliding and other hillslope processes. Yet the distribution and tensile strength of roots depends on a number of geomorphically-influenced parameters, including soil moisture. Our field-based study investigated the effects of topography on root distributions, tensile strengths, and cohesion. Systematic differences in plant species distribution and soil properties are found in the hollow-nose topography of soil-mantled landscapes; with hollows containing thick colluvial soils and mesic tree species and noses containing thinner, more differentiated soils and more xeric species. We investigated whether these topographic variations in geomorphic and ecologic properties affected the spatial distribution of root cohesion by measuring the distribution and tensile strength of roots from soil pits dug downslope of fifteen individual trees in the Coweeta Hydrologic Laboratory, North Carolina. Our soil pits were located to capture variance in plant species (10 species total), topographic positions (nose, hollow), and sizes (a range of DBH between 5 cm and 60 cm). Root tensile strengths showed little variance with different species, but showed strong differences as a function of topography, with nose roots stronger than hollow roots. Similarly, within species, root cellulose content was systematically greater in trees on nose positions compared to those in hollows. For all species, roots were concentrated close to the soil surface (at least 70% of biomass occurred within 50 cm of the surface) and variations in this pattern were primarily a function of topographic position. Hollow roots were more evenly distributed in the soil column than those on noses, yet trees located on noses had higher mean root cohesion than those in hollows because of a higher root tensile force. These data provide an

  10. A walking programme and a supervised exercise class versus usual physiotherapy for chronic low back pain: a single-blinded randomised controlled trial. (The Supervised Walking In comparison to Fitness Training for Back Pain (SWIFT) Trial).

    LENUS (Irish Health Repository)

    Hurley, Deirdre A

    2009-01-01

    BACKGROUND: Chronic low back pain (CLBP) is a persistent disabling condition with rising significant healthcare, social and economic costs. Current research supports the use of exercise-based treatment approaches that encourage people with CLBP to assume a physically active role in their recovery. While international clinical guidelines and systematic reviews for CLBP support supervised group exercise as an attractive first-line option for treating large numbers of CLBP patients at low cost, barriers to their delivery include space and time restrictions in healthcare settings and poor patient attendance. The European Clinical Guidelines have identified the need for research in the use of brief\\/minimal contact self-activation interventions that encourage participation in physical activity for CLBP. Walking may be an ideally suited form of individualized exercise prescription as it is easy to do, requires no special skills or facilities, and is achievable by virtually all ages with little risk of injury, but its effectiveness for LBP is unproven. METHODS AND DESIGN: This study will be an assessor-blinded randomized controlled trial that will investigate the difference in clinical effectiveness and costs of an individualized walking programme and a supervised general exercise programme compared to usual physiotherapy, which will act as the control group, in people with chronic low back pain. A sample of 246 patients will be recruited in Dublin, Ireland through acute general hospital outpatient physiotherapy departments that provide treatment for people with CLBP. Patients will be randomly allocated to one of the three groups in a concealed manner. The main outcomes will be functional disability, pain, quality of life, fear avoidance, back beliefs, physical activity, satisfaction and costs, which will be evaluated at baseline, and 3, 6 and 12 months [follow-up by pre-paid postage]. Qualitative telephone interviews and focus groups will be embedded in the research

  11. Method for rudder roll stabilization control by maintaining ship speed

    Directory of Open Access Journals (Sweden)

    LIU Zhiquan

    2017-01-01

    Full Text Available A ship navigating on the surface of the water may experience greater resistance, adversely affect-ing its speed and leading to energy loss. The added resistance of surface ships in both still water and waves are investigated, and the computation method of total speed loss is presented. An autopilot system is intro-duced to constrain the speed loss, and course keeping and rudder roll stabilization sliding mode control laws are proposed according to a compact control strategy. The two working conditions of "heading" and "heading plus anti-roll" are discussed, including roll stabilization, heading error, speed maintenance and rudder abrasion. The results show that the speed can be effectively maintained using this method, and from a commercial point of view, the fin-rudder roll stabilization control is not recommended for vessels equipped with both fins and rudders.

  12. Adaptive Dynamic Programming for Control Algorithms and Stability

    CERN Document Server

    Zhang, Huaguang; Luo, Yanhong; Wang, Ding

    2013-01-01

    There are many methods of stable controller design for nonlinear systems. In seeking to go beyond the minimum requirement of stability, Adaptive Dynamic Programming for Control approaches the challenging topic of optimal control for nonlinear systems using the tools of  adaptive dynamic programming (ADP). The range of systems treated is extensive; affine, switched, singularly perturbed and time-delay nonlinear systems are discussed as are the uses of neural networks and techniques of value and policy iteration. The text features three main aspects of ADP in which the methods proposed for stabilization and for tracking and games benefit from the incorporation of optimal control methods: • infinite-horizon control for which the difficulty of solving partial differential Hamilton–Jacobi–Bellman equations directly is overcome, and  proof provided that the iterative value function updating sequence converges to the infimum of all the value functions obtained by admissible control law sequences; • finite-...

  13. Optimal Sliding Mode Controllers for Attitude Stabilization of Flexible Spacecraft

    Directory of Open Access Journals (Sweden)

    Chutiphon Pukdeboon

    2011-01-01

    Full Text Available The robust optimal attitude control problem for a flexible spacecraft is considered. Two optimal sliding mode control laws that ensure the exponential convergence of the attitude control system are developed. Integral sliding mode control (ISMC is applied to combine the first-order sliding mode with optimal control and is used to control quaternion-based spacecraft attitude manoeuvres with external disturbances and an uncertainty inertia matrix. For the optimal control part the state-dependent Riccati equation (SDRE and optimal Lyapunov techniques are employed to solve the infinite-time nonlinear optimal control problem. The second method of Lyapunov is used to guarantee the stability of the attitude control system under the action of the proposed control laws. An example of multiaxial attitude manoeuvres is presented and simulation results are included to verify the usefulness of the developed controllers.

  14. A study of offshore wind HVDC system stability and control

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hanchao; Sun, Jian [Rensselaer Polytechnic Institute, Troy, NY (United States). Dept. of Electrical, Computer and Systems Engineering

    2011-07-01

    This work is concerned with the stability and control of ac power collection buses in offshore wind farms with high-voltage dc (HVDC) transmission connection to onshore power grid. The focus of the work is high-frequency interactions among the wind turbines, the ac collection bus and the filters, as well as the HVDC rectifier. Both voltage-source converter and line-commutated converter based HVDC systems are considered. To study high-frequency stability, particularly harmonic resonance in the ac bus, small-signal impedance models are developed for the wind inverters and the HVDC rectifier by using harmonic linearization techniques. An impedance-based stability criterion is applied to assess system stability in both positive- and negative-sequence domain. Small-signal stability conditions and requirements are developed from analytical impedance models. Detailed system-level simulation is used to validated the small-signal analysis. The goal of the study is to develop system design and control techniques that minimize the cost of the offshore infrastructure while guaranteeing system stability and power quality. (orig.)

  15. Stabilization of third-order bilinear systems using constant controls

    Directory of Open Access Journals (Sweden)

    A. E. Golubev

    2014-01-01

    Full Text Available This paper deals with the zero equilibrium stabilization for dynamical systems that have control input singularities. A dynamical system with scalar control input is called nonregular if the coefficient of input becomes null on a subset of the phase space that contains the origin. One of the classes of nonregular dynamical systems is represented by bilinear systems. In case of second-order bilinear systems the necessary and sufficient conditions for the zero equilibrium stabilizability are known in the literature. However, in general case the stabilization problem in the presence of control input singularities has not been solved yet.In this note we solve the problem of the zero equilibrium stabilization for the third-order bilinear dynamical systems given in a canonical form. The solution is found in the class of constant controls. The necessary and sufficient conditions are obtained for the zero equilibrium stabilizability of the bilinear systems in question.The dependence of the zero equilibrium stabilizability on system parameter values is analyzed. The general criteria of stabilizability by means of constant controls are given for the bilinear systems in question. In case when all the system parameters have nonzero values the necessary and sufficient stabilizability conditions are proved. The case when some of the parameters are equal to zero is also considered.Further research can be focused on extending the obtained results to a higher-order case of bilinear and affine dynamical systems. The solution of the considered stabilization problem should also be found not only within constant controls but also in a class of state feedbacks, particularly, in the case when stabilizing constant control does not exist.One of the potential application areas for the obtained theoretical results is automatic control of technical plants like unmanned aerial vehicles and mobile robots.

  16. Effectiveness of the bucco-lingual technique within a school-based supervised toothbrushing program on preventing caries: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Frazão Paulo

    2011-03-01

    Full Text Available Abstract Background Supervised toothbrushing programs using fluoride dentifrice have reduced caries increment. However there is no information about the effectiveness of the professional cross-brushing technique within a community intervention. The aim was to assess if the bucco-lingual technique can increase the effectiveness of a school-based supervised toothbrushing program on preventing caries. Methods A randomized double-blinded controlled community intervention trial to be analyzed at an individual level was conducted in a Brazilian low-income fluoridated area. Six preschools were randomly assigned to the test and control groups and 284 five-year-old children presenting at least one permanent molar with emerged/sound occlusal surface participated. In control group, oral health education and dental plaque dying followed by toothbrushing with fluoride dentifrice supervised directly by a dental assistant, was developed four times per year. At the remaining school days the children brushed their teeth under indirect supervising of the teachers. In test group, children also underwent a professional cross-brushing on surfaces of first permanent molar rendered by a specially trained dental assistant five times per year. Enamel and dentin caries were recorded on buccal, occlusal and lingual surfaces of permanent molars during 18-month follow-up. Exposure time of surfaces was calculated and incidence density ratio was estimated using Poisson regression model. Results Difference of 21.6 lesions per 1,000 children between control and test groups was observed. Among boys whose caries risk was higher compared to girls, incidence density was 50% lower in test group (p = 0.016. Conclusion Modified program was effective among the boys. It is licit to project a relevant effect in a larger period suggesting in a broader population substantial reduction of dental care needs. Trial registration ISRCTN18548869.

  17. Strong stabilization servo controller with optimization of performance criteria.

    Science.gov (United States)

    Sarjaš, Andrej; Svečko, Rajko; Chowdhury, Amor

    2011-07-01

    Synthesis of a simple robust controller with a pole placement technique and a H(∞) metrics is the method used for control of a servo mechanism with BLDC and BDC electric motors. The method includes solving a polynomial equation on the basis of the chosen characteristic polynomial using the Manabe standard polynomial form and parametric solutions. Parametric solutions are introduced directly into the structure of the servo controller. On the basis of the chosen parametric solutions the robustness of a closed-loop system is assessed through uncertainty models and assessment of the norm ‖•‖(∞). The design procedure and the optimization are performed with a genetic algorithm differential evolution - DE. The DE optimization method determines a suboptimal solution throughout the optimization on the basis of a spectrally square polynomial and Šiljak's absolute stability test. The stability of the designed controller during the optimization is being checked with Lipatov's stability condition. Both utilized approaches: Šiljak's test and Lipatov's condition, check the robustness and stability characteristics on the basis of the polynomial's coefficients, and are very convenient for automated design of closed-loop control and for application in optimization algorithms such as DE. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

  18. Robust stability bounds for multi-delay networked control systems

    Science.gov (United States)

    Seitz, Timothy; Yedavalli, Rama K.; Behbahani, Alireza

    2018-04-01

    In this paper, the robust stability of a perturbed linear continuous-time system is examined when controlled using a sampled-data networked control system (NCS) framework. Three new robust stability bounds on the time-invariant perturbations to the original continuous-time plant matrix are presented guaranteeing stability for the corresponding discrete closed-loop augmented delay-free system (ADFS) with multiple time-varying sensor and actuator delays. The bounds are differentiated from previous work by accounting for the sampled-data nature of the NCS and for separate communication delays for each sensor and actuator, not a single delay. Therefore, this paper expands the knowledge base in multiple inputs multiple outputs (MIMO) sampled-data time delay systems. Bounds are presented for unstructured, semi-structured, and structured perturbations.

  19. Stability and servo-control of the crystal pulling process

    International Nuclear Information System (INIS)

    Johansen, T.H.

    1990-11-01

    The paper analyzes why the crystal pulling process needs servo-control, and how it can be implemented. Special emphasis is put on the fundamental question of inherent stability, and how to interpret the signal from a balance when the weighing method is used for cystal diameter detection. 15 refs., 13 figs

  20. 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...

  1. Robust stabilization of nonlinear systems by quantized and ternary control

    NARCIS (Netherlands)

    Persis, Claudio De

    2009-01-01

    Results on the problem of stabilizing a nonlinear continuous-time minimum-phase system by a finite number of control or measurement values are presented. The basic tool is a discontinuous version of the so-called semi-global backstepping lemma. We derive robust practical stabilizability results by

  2. Synthetic Jets Flow Control on a vertical stabilizer

    Science.gov (United States)

    Rathay, Nicholas; Boucher, Matthew; Amitay, Michael

    2011-11-01

    The vertical stabilizer on most commercial transport aircraft is much larger than required for stability and control. The tail is significantly oversized in order to maintain controllability in the event of asymmetric engine failure and meet flying qualities requirements related to dynamic motion. Using aerodynamic flow control techniques, it may be possible to reduce the size of the tail while maintaining similar control authority during inclement flight conditions. Reducing the size of the tail decreases the weight and the drag of the airplane, which results in considerable savings in fuel costs. In this work, it is shown that synthetic jet (zero-net-mass-flux) actuators are capable of reattaching the separated flow on the rudder and augmenting the performance of the stabilizer. Experiments were conducted in an open-return wind tunnel on a 1/25th scale model of a vertical stabilizer and a partial fuselage section. The surface pressure, aerodynamic loads and data acquired with a Stereo PIV system were used to investigate the effectiveness of this technology as well as provide a more detailed analysis of the flowfield and showed that the synthetic jets are capable of augmenting the side-force by up to 20%.

  3. Microgrid Stability Controller Based on Adaptive Robust Total SMC

    DEFF Research Database (Denmark)

    Su, Xiaoling; Han, Minxiao; Guerrero, Josep M.

    2015-01-01

    This paper presents a microgrid stability controller (MSC) in order to provide existing DGs the additional functionality of working in islanding mode without changing their control strategies in grid-connected mode and to enhance the stability of the microgrid. Microgrid operating characteristics....... The MSC provides fast dynamic response and robustness to the microgrid. When the system is operating in grid-connected mode, it is able to improve the controllability of the exchanged power between the microgrid and the utility grid, while smoothing DG’s output power. When the microgrid is operating...... and mathematical models of the MSC indicate that the system is inherently nonlinear and time-variable. Therefore, this paper proposes an adaptive robust total sliding-mode control (ARTSMC) system for the MSC. It is proved that the ARTSMC system is insensitive to parametric uncertainties and external disturbances...

  4. BRONCHIAL ASTHMA SUPERVISION AMONG TEENAGERS

    Directory of Open Access Journals (Sweden)

    N.M. Nenasheva

    2008-01-01

    Full Text Available The article highlights the results of the act test based bronchial asthma supervision evaluation among teenagers and defines the interrelation of the objective and subjective asthma supervision parameters. The researchers examined 214 male teenagers aged from 16 to 18, suffering from the bronchial asthma, who were sent to the allergy department to verify the diagnosis. Bronchial asthma supervision evaluation was assisted by the act test. The research has showed that over a half (56% of teenagers, suffering from mild bronchial asthma, mention its un control course, do not receive any adequate pharmacotherapy and are consequently a risk group in terms of the bronchial asthma exacerbation. Act test results correlate with the functional indices (fev1, as well as with the degree of the bronchial hyperresponsiveness, which is one of the markers of an allergic inflammation in the lower respiratory passages.Key words: bronchial asthma supervision, act test, teenagers.

  5. Doping control container for urine stabilization: a pilot study.

    Science.gov (United States)

    Tsivou, Maria; Giannadaki, Evangelia; Hooghe, Fiona; Roels, Kris; Van Gansbeke, Wim; Garribba, Flaminia; Lyris, Emmanouil; Deventer, Koen; Mazzarino, Monica; Donati, Francesco; Georgakopoulos, Dimitrios G; Van Eenoo, Peter; Georgakopoulos, Costas G; de la Torre, Xavier; Botrè, Francesco

    2017-05-01

    Urine collection containers used in the doping control collection procedure do not provide a protective environment for urine, against degradation by microorganisms and proteolytic enzymes. An in-house chemical stabilization mixture was developed to tackle urine degradation problems encountered in human sport samples, in cases of microbial contamination or proteolytic activity. The mixture consists of antimicrobial substances and protease inhibitors for the simultaneous inactivation of a wide range of proteolytic enzymes. It has already been tested in lab-scale, as part of World Anti-Doping Agency's (WADA) funded research project, in terms of efficiency against microbial and proteolytic activity. The present work, funded also by WADA, is a follow-up study on the improvement of chemical stabilization mixture composition, application mode and limitation of interferences, using pilot urine collection containers, spray-coated in their internal surface with the chemical stabilization mixture. Urine in plastic stabilized collection containers have been gone through various incubation cycles to test for stabilization efficiency and analytical matrix interferences by three WADA accredited Laboratories (Athens, Ghent, and Rome). The spray-coated chemical stabilization mixture was tested against microorganism elimination and steroid glucuronide degradation, as well as enzymatic breakdown of proteins, such as intact hCG, recombinant erythropoietin and small peptides (GHRPs, ipamorelin), induced by proteolytic enzymes. Potential analytical interferences, observed in the presence of spray-coated chemical stabilization mixture, were recorded using routine screening procedures. The results of the current study support the application of the spray-coated plastic urine container, in the doping control collection procedure. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  6. Security system signal supervision

    International Nuclear Information System (INIS)

    Chritton, M.R.; Matter, J.C.

    1991-09-01

    This purpose of this NUREG is to present technical information that should be useful to NRC licensees for understanding and applying line supervision techniques to security communication links. A review of security communication links is followed by detailed discussions of link physical protection and DC/AC static supervision and dynamic supervision techniques. Material is also presented on security for atmospheric transmission and video line supervision. A glossary of security communication line supervision terms is appended. 16 figs

  7. Stability Control of Vehicle Emergency Braking with Tire Blowout

    OpenAIRE

    Chen, Qingzhang; Liu, Youhua; Li, Xuezhi

    2014-01-01

    For the stability control and slowing down the vehicle to a safe speed after tire failure, an emergency automatic braking system with independent intellectual property is developed. After the system has received a signal of tire blowout, the automatic braking mode of the vehicle is determined according to the position of the failure tire and the motion state of vehicle, and a control strategy for resisting tire blowout additional yaw torque and deceleration is designed to slow down vehicle to...

  8. Fuzzy logic controller for stabilization of biped robot gait

    Directory of Open Access Journals (Sweden)

    Ryadchikov I.V.

    2018-01-01

    Full Text Available The article centers round the problem of stabilization of biped robot gait through smoothing out the jumps of first and second order derivatives of a biped robot control vector using the fuzzy logic approach. The structure of a composite Takagi-Sugeno fuzzy logic controller developed by the authors is presented. The simulation study of a robot gait with climbing an obstacle is carried out and the results provided in the article showed that the developed controller performed significantly better than the analytical formula model in terms of smoothing out the derivatives of the control vector.

  9. Supervision functions - Secure operation of sustainable power systems

    DEFF Research Database (Denmark)

    Morais, Hugo; Zhang, Xinxin; Lind, Morten

    2013-01-01

    of power systems operation control. The use of PMUs allows more penetration of DG mainly, with technologies based on renewable resources with intermittent and unpredictable operation such a wind power. This paper introduces the Secure Operation of Sustainable Power Systems (SOSPO) project. The SOSPO...... project tries to respond to the question "How to ensure a secure operation of the future power system where the operating point is heavily is fluctuating?" focusing in the Supervision module architecture and in the power system operation states. The main goal of Supervision module is to determine...... the power system operation state based on new stability and security parameters derived from PMUs measurement and coordinate the use of automatic and manual control actions. The coordination of the control action is based not only in the static indicators but also in the performance evaluation of control...

  10. The electric power engineering handbook power system stability and control

    CERN Document Server

    Grisby, Leonard L

    2012-01-01

    With contributions from worldwide leaders in the field, Power System Stability and Control, Third Edition (part of the five-volume set, The Electric Power Engineering Handbook) updates coverage of recent developments and rapid technological growth in essential aspects of power systems. Edited by L.L. Grigsby, a respected and accomplished authority in power engineering, and section editors Miroslav Begovic, Prabha Kundur, and Bruce Wollenberg, this reference presents substantially new and revised content. Topics covered include: * Power System Protection * Power System Dynamics and Stability *

  11. Stabilization and Synchronization of Memristive Chaotic Circuits by Impulsive Control

    Directory of Open Access Journals (Sweden)

    Limin Zou

    2017-01-01

    Full Text Available The purpose of this note is to study impulsive control and synchronization of memristor based chaotic circuits shown by Muthuswamy. We first establish a less conservative sufficient condition for the stability of memristor based chaotic circuits. After that, we discuss the effect of errors on stability. Meanwhile, we also discuss impulsive synchronization of two memristor based chaotic systems. Our results are more general and more applicable than the ones shown by Yang, Li, and Huang. Finally, several numerical examples are given to show the effectiveness of our methods.

  12. Robust stability in predictive control with soft constraints

    DEFF Research Database (Denmark)

    Thomsen, Sven Creutz; Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2010-01-01

    In this paper we take advantage of the primary and dual Youla parameterizations for setting up a soft constrained model predictive control (MPC) scheme for which stability is guaranteed in face of norm-bounded uncertainties. Under special conditions guarantees are also given for hard input...... constraints. In more detail, we parameterize the MPC predictions in terms of the primary Youla parameter and use this parameter as the online optimization variable. The uncertainty is parameterized in terms of the dual Youla parameter. Stability can then be guaranteed through small gain arguments on the loop...

  13. Robust stability in constrained predictive control through the Youla parameterisations

    DEFF Research Database (Denmark)

    Thomsen, Sven Creutz; Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2011-01-01

    In this article we take advantage of the primary and dual Youla parameterisations to set up a soft constrained model predictive control (MPC) scheme. In this framework it is possible to guarantee stability in face of norm-bounded uncertainties. Under special conditions guarantees are also given...... for hard input constraints. In more detail, we parameterise the MPC predictions in terms of the primary Youla parameter and use this parameter as the on-line optimisation variable. The uncertainty is parameterised in terms of the dual Youla parameter. Stability can then be guaranteed through small gain...

  14. Stability and Control of Human Trunk Movement During Walking.

    Science.gov (United States)

    Wu, Q.; Sepehri, N.; Thornton-Trump, A. B.; Alexander, M.

    1998-01-01

    A mathematical model has been developed to study the control mechanisms of human trunk movement during walking. The trunk is modeled as a base-excited inverted pendulum with two-degrees of rotational freedom. The base point, corresponding to the bony landmark of the sacrum, can move in three-dimensional space in a general way. Since the stability of upright posture is essential for human walking, a controller has been designed such that the stability of the pendulum about the upright position is guaranteed. The control laws are developed based on Lyapunov's stability theory and include feedforward and linear feedback components. It is found that the feedforward component plays a critical role in keeping postural stability, and the linear feedback component, (resulting from viscoelastic function of the musculoskeletal system) can effectively duplicate the pattern of trunk movement. The mathematical model is validated by comparing the simulation results with those based on gait measurements performed in the Biomechanics Laboratory at the University of Manitoba.

  15. Model reference adaptive control and adaptive stability augmentation

    DEFF Research Database (Denmark)

    Henningsen, Arne; Ravn, Ole

    1993-01-01

    A comparison of the standard concepts in MRAC design suggests that a combination of the implicit and the explicit design techniques may lead to an improvement of the overall system performance in the presence of unmodelled dynamics. Using the ideas of adaptive stability augmentation a combined...... stability augmented model reference design is proposed. By utilizing the closed-loop control error, a simple auxiliary controller is tuned, using a normalized MIT rule for the parameter adjustment. The MIT adjustment is protected against the effects of unmodelled dynamics by lowpass filtering...... of the gradient. The proposed method is verified through simulation results indicating that the method may lead to an improvement of the model reference controller in the presence of unmodelled dynamics...

  16. Output Feedback Stabilization with Nonlinear Predictive Control: Asymptotic properties

    Directory of Open Access Journals (Sweden)

    Lars Imsland

    2003-07-01

    Full Text Available State space based nonlinear model predictive control (NM PC needs the state for the prediction of the system behaviour. Unfortunately, for most applications, not all states are directly measurable. To recover the unmeasured states, typically a stable state observer is used. However, this implies that the stability of the closed-loop should be examined carefully, since no general nonlinear separation principle exists. Recently semi-global practical stability results for output feedback NMPC using a high-gain observer for state estimation have been established. One drawback of this result is that (in general the observer gain must be increased, if the desired set the state should converge to is made smaller. We show that under slightly stronger assumptions, not only practical stability, but also convergence of the system states and observer error to the origin for a sufficiently large but bounded observer gain can be achieved.

  17. Stability Boundaries for Offshore Wind Park Distributed Voltage Control

    DEFF Research Database (Denmark)

    Gryning, Mikkel P.S.; Wu, Qiuwei; Kocewiak, Lukasz

    2017-01-01

    pilot control. Using data from the actual wind power plant, all stabilizing subsystem voltage proportional-integral controller parameters are first characterized based on their Hurwitz signature. Inner loop current control is then designed using Internal Mode Control principles, and guidelines for feed......In order to identify mechanisms causing slow reactive power oscillations observed in an existing offshore wind power plant, and be able to avoid similar events in the future, voltage control is studied in this paper for a plant with a static synchronous compensator, type-4 wind turbines and a park...... forward filter design are given to obtain required disturbance rejection properties. The paper contributes by providing analytical relations between power plant control, droop, sampling time, electrical parameters and voltage control characteristics, and by assessing frequencies and damping of reactive...

  18. Transient stability improvement by nonlinear controllers based on tracking

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, Juan M. [Centro de Investigacion y Estudios Avanzados, Guadalajara, Mexico. Av. Cientifica 1145. Col. El Bajio. Zapopan, Jal. 45015 (Mexico); Arroyave, Felipe Valencia; Correa Gutierrez, Rosa Elvira [Universidad Nacional de Colombia, Sede Medellin. Facultad de Minas, Escuela de Mecatronica (Colombia)

    2011-02-15

    This paper deals with the control problem in multi-machine electric power systems, which represent complex great scale nonlinear systems. Thus, the controller design is a challenging problem. These systems are subjected to different perturbations, such as short circuits, connection and/or disconnection of loads, lines, or generators. Then, the utilization of controllers which guarantee good performance under those perturbations is required in order to provide electrical energy to the loads with admissible stability margins. The proposed controllers are based on a systematic strategy, which calculate nonlinear controllers for generating units in a power plant, both for voltage and velocity regulation. The formulation allows designing controllers in a multi-machine power system without intricate calculations. Results on a power system of the open research indicate the proposition's suitability. The problem is formulated as a tracking problem. The designed controllers may be implemented in any electric power system. (author)

  19. Discharge optimization and the control of edge stability

    International Nuclear Information System (INIS)

    Nave, M.F.F.; Lomas, P.J.; Huysmans, G.T.A.

    1999-01-01

    Discharge optimization for improving MHD stability of both core and edge was essential for the achievement of record fusion power discharges, in the ELM-free hot ion H mode regime, in the recent JET DT operation. The techniques used to increase edge stability are described. In particular the successful technique of current rampdown used to suppress the outer mode is reported. The increased stability of the outer mode by decreasing the edge current density confirms its identification as an n = 1 external kink. Decreasing the plasma current, however, decreases the ELM-free period, which is consistent with stability calculations that show an earlier onset of the ballooning limit. In order to increase external kink stability without causing a deterioration in the ELM-free period, a compromise was achieved by using plasma current rampdown, while working at the highest plasma current values possible. Results from a plasma current scan show that at the time of occurrence of the first giant ELM, the plasma stored energy, as well as the pressure measured at the top of the edge pedestal increase linearly with plasma current, for a given plasma configuration and power. This is consistent with models of the edge transport barrier, where the transport barrier width is proportional to the ion (or fast ion) poloidal Larmor radius. The MHD observations in DT and deuterium only discharges were found to be similar. Thus the experience gained on the control of MHD modes in deuterium plasmas could be fully exploited in the DT campaign. (author)

  20. Control Design of a Nonlinear Controller to Stabilize the Nonlinear ...

    African Journals Online (AJOL)

    inyangs

    protocol employed to combat the problem of proper queue utilization, busty packet drop and adaptable delay. TCP .... This case considers a delay on the control input only and the link capacity is made to be very large to ... We take the derivative of equation (13) with respect to t and apply the Leibniz integrator rule to obtain.

  1. Stability and synchronization control of stochastic neural networks

    CERN Document Server

    Zhou, Wuneng; Zhou, Liuwei; Tong, Dongbing

    2016-01-01

    This book reports on the latest findings in the study of Stochastic Neural Networks (SNN). The book collects the novel model of the disturbance driven by Levy process, the research method of M-matrix, and the adaptive control method of the SNN in the context of stability and synchronization control. The book will be of interest to university researchers, graduate students in control science and engineering and neural networks who wish to learn the core principles, methods, algorithms and applications of SNN.

  2. To evaluate if increased supervision and support of South African Government health workers' home visits improves maternal and child outcomes: study protocol for a randomized control trial.

    Science.gov (United States)

    Rotheram-Borus, Mary Jane; Le Roux, Karl; Le Roux, Ingrid M; Christodoulou, Joan; Laurenzi, Christina; Mbewu, Nokwanele; Tomlinson, Mark

    2017-08-07

    Concurrent epidemics of HIV, depression, alcohol abuse, and partner violence threaten maternal and child health (MCH) in South Africa. Although home visiting has been repeatedly demonstrated efficacious in research evaluations, efficacy disappears when programs are scaled broadly. In this cluster randomized controlled trial (RCT), we examine whether the benefits of ongoing accountability and supervision within an existing government funded and implemented community health workers (CHW) home visiting program ensure the effectiveness of home visiting. In the deeply rural, Eastern Cape of South Africa, CHW will be hired by the government and will be initially trained by the Philani Programme to conduct home visits with all pregnant mothers and their children until the children are 2 years old. Eight clinics will be randomized to receive either (1) the Accountable Care Condition in which additional monitoring and accountability systems that Philani routinely uses are implemented (4 clinics, 16 CHW, 450 households); or (2) a Standard Care Condition of initial Philani training, but with supervision and monitoring being delivered by local government structures and systems (4 clinics, 21 CHW, 450 households). In the Accountable Care Condition areas, the CHW's mobile phone reports, which are time-location stamped, will be monitored and data-informed supervision will be provided, as well as monitoring growth, medical adherence, mental health, and alcohol use outcomes. Interviewers will independently assess outcomes at pregnancy at 3, 6, 15, and 24 months post-birth. The primary outcome will be a composite score of documenting maternal HIV/TB testing, linkage to care, treatment adherence and retention, as well as child physical growth, cognitive functioning, and child behavior and developmental milestones. The proposed cluster RCT will evaluate whether routinely implementing supervision and accountability procedures and monitoring CHWs' over time will improve MCH outcomes

  3. Transient stability enhancement of modern power grid using predictive Wide-Area Monitoring and Control

    Science.gov (United States)

    Yousefian, Reza

    This dissertation presents a real-time Wide-Area Control (WAC) designed based on artificial intelligence for large scale modern power systems transient stability enhancement. The WAC using the measurements available from Phasor Measurement Units (PMUs) at generator buses, monitors the global oscillations in the system and optimally augments the local excitation system of the synchronous generators. The complexity of the power system stability problem along with uncertainties and nonlinearities makes the conventional modeling non-practical or inaccurate. In this work Reinforcement Learning (RL) algorithm on the benchmark of Neural Networks (NNs) is used to map the nonlinearities of the system in real-time. This method different from both the centralized and the decentralized control schemes, employs a number of semi-autonomous agents to collaborate with each other to perform optimal control theory well-suited for WAC applications. Also, to handle the delays in Wide-Area Monitoring (WAM) and adapt the RL toward the robust control design, Temporal Difference (TD) is proposed as a solver for RL problem or optimal cost function. However, the main drawback of such WAC design is that it is challenging to determine if an offline trained network is valid to assess the stability of the power system once the system is evolved to a different operating state or network topology. In order to address the generality issue of NNs, a value priority scheme is proposed in this work to design a hybrid linear and nonlinear controllers. The algorithm so-called supervised RL is based on mixture of experts, where it is initialized by linear controller and as the performance and identification of the RL controller improves in real-time switches to the other controller. This work also focuses on transient stability and develops Lyapunov energy functions for synchronous generators to monitor the stability stress of the system. Using such energies as a cost function guarantees the convergence

  4. Simulator protection, control and supervision systems: a tool for empowerment of operation and maintenance; Simulador de sistemas de protecao, controle e supervisao: uma ferramenta para capacitacao da operacao e manutencao

    Energy Technology Data Exchange (ETDEWEB)

    Moutinho, J.A.P. [Centrais Eletricas do Norte do Brasil S.A. (ELETRONORTE), Belem, PA (Brazil). Regional de Transmissao do Para. Div. de Engenharia de Automacao, Protecao e Medicao], E-mail: beck@eln.gov.br

    2009-07-01

    The use of digital technology in protection, control and supervision equipment has resulted in the electricity sector companies, new behavior in electrical management systems given his versatility in the implementation of protection system as well as cost reduction in traffic information of power equipment to the man-machine interfaces (MMI) to the system operator. With the capabilities of digital technology it is possible provide simulated systems to allow the training of operations teams of the system, providing resources for development for engineers and maintenance technicians, and above all offer platform for analysis of events in the electrical system. This paper presents the development of a simulator protective relays, control and supervision applied to ELETRONORTE substations. The simulator of protective relays, control and supervision consists of information reproduction in the operator's MMI of the electrical system originated in the units of protection, control and supervision. This information is developed from a software that has the same communication protocol with the original units.

  5. Human Supervision of Multiple Autonomous Vehicles

    Science.gov (United States)

    2013-03-22

    AFRL-RH-WP-TR-2013-0143 HUMAN SUPERVISION OF MULTIPLE AUTONOMOUS VEHICLES Heath A. Ruff Ball...REPORT TYPE Interim 3. DATES COVERED (From – To) 09-16-08 – 03-22-13 4. TITLE AND SUBTITLE HUMAN SUPERVISION OF MULTIPLE AUTONOMOUS VEHICLES 5a...Supervision of Multiple Autonomous Vehicles To support the vision of a system that enables a single operator to control multiple next-generation

  6. Stability control of a flexible maneuverable tethered space net robot

    Science.gov (United States)

    Zhang, Fan; Huang, Panfeng

    2018-04-01

    As a promising solution for active space debris capture and removal, a maneuverable Tethered Space Net Robot (TSNR) is proposed as an improved Space Tethered Net (TSN). In addition to the advantages inherit to the TSN, the TSNR's maneuverability expands the capture's potential. However, oscillations caused by the TSNR's flexibility and elasticity of make higher requests of the control scheme. Based on the dynamics model, a modified adaptive super-twisting sliding mode control scheme is proposed in this paper for TSNR stability control. The proposed continuous control force can effectively suppress oscillations. Theoretical verification and numerical simulations demonstrate that the desired trajectory can be tracked steadily and efficiently by employing the proposed control scheme.

  7. Mentoring, coaching and supervision

    OpenAIRE

    McMahon, Samantha; Dyer, Mary; Barker, Catherine

    2016-01-01

    This chapter considers the purpose of coaching, mentoring and supervision in early childhood eduaction and care. It examines a number of different approaches and considers the key skills required for effective coaching, mentoring and supervision.

  8. Effects of a Supervised versus an Unsupervised Combined Balance and Strength Training Program on Balance and Muscle Power in Healthy Older Adults: A Randomized Controlled Trial.

    Science.gov (United States)

    Lacroix, André; Kressig, Reto W; Muehlbauer, Thomas; Gschwind, Yves J; Pfenninger, Barbara; Bruegger, Othmar; Granacher, Urs

    2016-01-01

    Losses in lower extremity muscle strength/power, muscle mass and deficits in static and particularly dynamic balance due to aging are associated with impaired functional performance and an increased fall risk. It has been shown that the combination of balance and strength training (BST) mitigates these age-related deficits. However, it is unresolved whether supervised versus unsupervised BST is equally effective in improving muscle power and balance in older adults. This study examined the impact of a 12-week BST program followed by 12 weeks of detraining on measures of balance and muscle power in healthy older adults enrolled in supervised (SUP) or unsupervised (UNSUP) training. Sixty-six older adults (men: 25, women: 41; age 73 ± 4 years) were randomly assigned to a SUP group (2/week supervised training, 1/week unsupervised training; n = 22), an UNSUP group (3/week unsupervised training; n = 22) or a passive control group (CON; n = 22). Static (i.e., Romberg Test) and dynamic (i.e., 10-meter walk test) steady-state, proactive (i.e., Timed Up and Go Test, Functional Reach Test), and reactive balance (e.g., Push and Release Test), as well as lower extremity muscle power (i.e., Chair Stand Test; Stair Ascent and Descent Test) were tested before and after the active training phase as well as after detraining. Adherence rates to training were 92% for SUP and 97% for UNSUP. BST resulted in significant group × time interactions. Post hoc analyses showed, among others, significant training-related improvements for the Romberg Test, stride velocity, Timed Up and Go Test, and Chair Stand Test in favor of the SUP group. Following detraining, significantly enhanced performances (compared to baseline) were still present in 13 variables for the SUP group and in 10 variables for the UNSUP group. Twelve weeks of BST proved to be safe (no training-related injuries) and feasible (high attendance rates of >90%). Deficits of balance and lower extremity muscle power can be

  9. Optimal preventive bank supervision

    OpenAIRE

    Belhaj, Mohamed; Klimenko, Nataliya

    2012-01-01

    Early regulator interventions into problem banks is one of the key suggestions of Basel Committee on Banking Supervision. However, no guidance is given on their design. To fill this gap, we outline an incentive-based preventive supervision strategy that eliminates bad asset management in banks. Two supervision techniques are combined: temporary regulatory administration and random audits. Our design ensures good management without excessive supervision costs, through a gradual adjustment of...

  10. A Supervision of Solidarity

    Science.gov (United States)

    Reynolds, Vikki

    2010-01-01

    This article illustrates an approach to therapeutic supervision informed by a philosophy of solidarity and social justice activism. Called a "Supervision of Solidarity", this approach addresses the particular challenges in the supervision of therapists who work alongside clients who are subjected to social injustice and extreme marginalization. It…

  11. Legislation and supervision

    International Nuclear Information System (INIS)

    1998-01-01

    In this part next aspects are described: (1) Legislative and supervision-related framework (reviews of structure of supervisory bodies; legislation; state supervision in the nuclear safety area, and state supervision in the area of health protection against radiation are given); (2) Operator's responsibility

  12. Stability Concerns for Indirect Consumer Control in Smart Grids

    DEFF Research Database (Denmark)

    Juelsgaard, Morten; Andersen, Palle; Wisniewski, Rafal

    2013-01-01

    by an external third party, and indirect consumer control through incentives and price signals. In this work we present a simple formulation of indirect control, where the behavior of each consumer, is governed by local optimization of energy consumption. The local optimization accounts for both cost of energy...... and distribution losses, as well as any discomfort incurred by consumers from any shift in energy consumption. Our work will illustrate that in the simplest formulation of indirect control, the stability is greatly affected of both the behavior of consumers, and the number of consumers to include. We will show how......Demand side management will be an important tool for maintaining a balanced electrical grid in the future, when the penetration of volatile resources, such as wind and solar energy increases. Recent research focuses on two different management approaches, namely direct consumer control...

  13. Stability of Closed Loop Controlled Repetitive Periodic System applied to control of CD-Player

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle

    2005-01-01

    In this paper a criterion for stability of specific control scheme for handling linear dynamic control systems with repetitive periodic sensor faults is derived. The given system and control scheme are described and defined. By combining these with the lifting technique a necessary and sufficient...

  14. Hybrid AC-High Voltage DC Grid Stability and Controls

    Science.gov (United States)

    Yu, Jicheng

    The growth of energy demands in recent years has been increasing faster than the expansion of transmission facility construction. This tendency cooperating with the continuous investing on the renewable energy resources drives the research, development, and construction of HVDC projects to create a more reliable, affordable, and environmentally friendly power grid. Constructing the hybrid AC-HVDC grid is a significant move in the development of the HVDC techniques; the form of dc system is evolving from the point-to-point stand-alone dc links to the embedded HVDC system and the multi-terminal HVDC (MTDC) system. The MTDC is a solution for the renewable energy interconnections, and the MTDC grids can improve the power system reliability, flexibility in economic dispatches, and converter/cable utilizing efficiencies. The dissertation reviews the HVDC technologies, discusses the stability issues regarding the ac and HVDC connections, proposes a novel power oscillation control strategy to improve system stability, and develops a nonlinear voltage droop control strategy for the MTDC grid. To verify the effectiveness the proposed power oscillation control strategy, a long distance paralleled AC-HVDC transmission test system is employed. Based on the PSCAD/EMTDC platform simulation results, the proposed power oscillation control strategy can improve the system dynamic performance and attenuate the power oscillations effectively. To validate the nonlinear voltage droop control strategy, three droop controls schemes are designed according to the proposed nonlinear voltage droop control design procedures. These control schemes are tested in a hybrid AC-MTDC system. The hybrid AC-MTDC system, which is first proposed in this dissertation, consists of two ac grids, two wind farms and a five-terminal HVDC grid connecting them. Simulation studies are performed in the PSCAD/EMTDC platform. According to the simulation results, all the three design schemes have their unique salient

  15. Stability analysis of multiple-robot control systems

    Science.gov (United States)

    Wen, John T.; Kreutz, Kenneth

    1989-01-01

    In a space telerobotic service scenario, cooperative motion and force control of multiple robot arms are of fundamental importance. Three paradigms to study this problem are proposed. They are distinguished by the set of variables used for control design. They are joint torques, arm tip force vectors, and an accelerated generalized coordinate set. Control issues related to each case are discussed. The latter two choices require complete model information, which presents practical modeling, computational, and robustness problems. Therefore, focus is on the joint torque control case to develop relatively model independent motion and internal force control laws. The rigid body assumption allows the motion and force control problems to be independently addressed. By using an energy motivated Lyapunov function, a simple proportional derivative plus gravity compensation type of motion control law is always shown to be stabilizing. The asymptotic convergence of the tracing error to zero requires the use of a generalized coordinate with the contact constraints taken into account. If a non-generalized coordinate is used, only convergence to a steady state manifold can be concluded. For the force control, both feedforward and feedback schemes are analyzed. The feedback control, if proper care has been taken, exhibits better robustness and transient performance.

  16. A fuzzy logic pitch angle controller for power system stabilization

    Energy Technology Data Exchange (ETDEWEB)

    Jauch, Clemens; Cronin, Tom; Sorensen, Poul [Wind Energy Department, Riso National Laboratory, PO Box 49, DK-4000 Roskilde, (Denmark); Jensen, Birgitte Bak [Institute of Energy Technology, Aalborg University, Pontoppidanstraede 101, DK-9220 Aalborg East, (Denmark)

    2006-07-12

    In this article the design of a fuzzy logic pitch angle controller for a fixed speed, active-stall wind turbine, which is used for power system stabilization, is presented. The system to be controlled, which is the wind turbine and the power system to which the turbine is connected, is described. The advantages of fuzzy logic control when applied to large-signal control of active-stall wind turbines are outlined. The general steps of the design process for a fuzzy logic controller, including definition of the controller inputs, set-up of the fuzzy rules and the method of defuzzification, are described. The performance of the controller is assessed by simulation, where the wind turbine's task is to dampen power system oscillations. In the scenario simulated for this work, the wind turbine has to ride through a transient short-circuit fault and subsequently contribute to the damping of the grid frequency oscillations that are caused by the transient fault. It is concluded that the fuzzy logic controller enables the wind turbine to dampen power system oscillations. It is also concluded that, owing to the inherent non-linearities in a wind turbine and the unpredictability of the whole system, the fuzzy logic controller is very suitable for this application. (Author).

  17. LOFT pump speed controller stability and accuracy analysis

    International Nuclear Information System (INIS)

    Good, R.R.

    1978-01-01

    Two system modifications to the primary coolant pumps motor generators control systems have recently been completed. The range of pump speed operation has been extended and the scoop tube positioner motor replaced. This has necessitated a re-analysis of PSMG stability throughout its range of operation. System accuracy requirements of less than 4 Hz differential pump speed when operating at less than 35 Hz and 8.5 Hz differential pump speed when operating at greater than 35 Hz can be guaranteed by specifying the gain of the system. The installation of the new scoop tube positioner motor will increase the PSMG system's bandwidth and stability. Low speed pump trips should be carefully evaluated if the pump's operational range is to extend to 10 Hz

  18. Steam Turbine Control Valve Stiction Effect on Power System Stability

    International Nuclear Information System (INIS)

    Halimi, B.

    2010-01-01

    One of the most important problems in power system dynamic stability is low frequency oscillations. This kind of oscillation has significant effects on the stability and security of the power system. In some previous papers, a fact was introduced that a steam pressure continuous fluctuation in turbine steam inlet pipeline may lead to a kind of low frequency oscillation of power systems. Generally, in a power generation plant, steam turbine system composes of some main components, i.e. a boiler or steam generator, stop valves, control valves and turbines that are connected by piping. In the conventional system, the turbine system is composed with a lot of stop and control valves. The steam is provided by a boiler or steam generator. In an abnormal case, the stop valve shuts of the steal flow to the turbine. The steam flow to the turbine is regulated by controlling the control valves. The control valves are provided to regulate the flow of steam to the turbine for starting, increasing or decreasing the power, and also maintaining speed control with the turbine governor system. Unfortunately, the control valve has inherent static friction (stiction) nonlinearity characteristics. Industrial surveys indicated that about 20-30% of all control loops oscillate due to valve problem caused by this nonlinear characteristic. In this paper, steam turbine control valve stiction effect on power system oscillation is presented. To analyze the stiction characteristic effect, firstly a model of control valve and its stiction characteristic are derived by using Newton's laws. A complete tandem steam prime mover, including a speed governing system, a four-stage steam turbine, and a shaft with up to for masses is adopted to analyze the performance of the steam turbine. The governor system consists of some important parts, i.e. a proportional controller, speed relay, control valve with its stiction characteristic, and stem lift position of control valve controller. The steam turbine has

  19. Stability and Bifurcation in Magnetic Flux Feedback Maglev Control System

    Directory of Open Access Journals (Sweden)

    Wen-Qing Zhang

    2013-01-01

    Full Text Available Nonlinear properties of magnetic flux feedback control system have been investigated mainly in this paper. We analyzed the influence of magnetic flux feedback control system on control property by time delay and interfering signal of acceleration. First of all, we have established maglev nonlinear model based on magnetic flux feedback and then discussed hopf bifurcation’s condition caused by the acceleration’s time delay. The critical value of delayed time is obtained. It is proved that the period solution exists in maglev control system and the stable condition has been got. We obtained the characteristic values by employing center manifold reduction theory and normal form method, which represent separately the direction of hopf bifurcation, the stability of the period solution, and the period of the period motion. Subsequently, we discussed the influence maglev system on stability of by acceleration’s interfering signal and obtained the stable domain of interfering signal. Some experiments have been done on CMS04 maglev vehicle of National University of Defense Technology (NUDT in Tangshan city. The results of experiments demonstrate that viewpoints of this paper are correct and scientific. When time lag reaches the critical value, maglev system will produce a supercritical hopf bifurcation which may cause unstable period motion.

  20. Microgrid Stability Controller Based on Adaptive Robust Total SMC

    Directory of Open Access Journals (Sweden)

    Xiaoling Su

    2015-03-01

    Full Text Available This paper presents a microgrid stability controller (MSC in order to provide existing distributed generation units (DGs the additional functionality of working in islanding mode without changing their control strategies in grid-connected mode and to enhance the stability of the microgrid. Microgrid operating characteristics and mathematical models of the MSC indicate that the system is inherently nonlinear and time-variable. Therefore, this paper proposes an adaptive robust total sliding-mode control (ARTSMC system for the MSC. It is proved that the ARTSMC system is insensitive to parametric uncertainties and external disturbances. The MSC provides fast dynamic response and robustness to the microgrid. When the system is operating in grid-connected mode, it is able to improve the controllability of the exchanged power between the microgrid and the utility grid, while smoothing the DGs’ output power. When the microgrid is operating in islanded mode, it provides voltage and frequency support, while guaranteeing seamless transition between the two operation modes. Simulation and experimental results show the effectiveness of the proposed approach.

  1. Biological stability of drinking water: controlling factors, methods and challenges

    Directory of Open Access Journals (Sweden)

    Emmanuelle ePrest

    2016-02-01

    Full Text Available Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and can lead to hygienic (e.g. development of opportunistic pathogens, aesthetic (e.g. deterioration of taste, odour, colour or operational (e.g. fouling or biocorrosion of pipes problems. Drinking water contains diverse microorganisms competing for limited available nutrients for growth. Bacterial growth and interactions are regulated by factors such as (i type and concentration of available organic and inorganic nutrients, (ii type and concentration of residual disinfectant, (iii presence of predators such as protozoa and invertebrates, (iv environmental conditions such as water temperature, and (v spatial location of microorganisms (bulk water, sediment or biofilm. Water treatment and distribution conditions in water mains and premise plumbing affect each of these factors and shape bacterial community characteristics (abundance, composition, viability in distribution systems. Improved understanding of bacterial interactions in distribution systems and of environmental conditions impact is needed for better control of bacterial communities during drinking water production and distribution. This article reviews (i existing knowledge on biological stability controlling factors and (ii how these factors are affected by drinking water production and distribution conditions. In addition, (iii the concept of biological stability is discussed in light of experience with well-established and new analytical methods, enabling high throughput analysis and in-depth characterization of bacterial communities in drinking water. We discuss how knowledge gained from novel techniques will improve design and monitoring of water treatment and distribution systems in order to

  2. Biological Stability of Drinking Water: Controlling Factors, Methods, and Challenges

    Science.gov (United States)

    Prest, Emmanuelle I.; Hammes, Frederik; van Loosdrecht, Mark C. M.; Vrouwenvelder, Johannes S.

    2016-01-01

    Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and can lead to hygienic (e.g., development of opportunistic pathogens), aesthetic (e.g., deterioration of taste, odor, color) or operational (e.g., fouling or biocorrosion of pipes) problems. Drinking water contains diverse microorganisms competing for limited available nutrients for growth. Bacterial growth and interactions are regulated by factors, such as (i) type and concentration of available organic and inorganic nutrients, (ii) type and concentration of residual disinfectant, (iii) presence of predators, such as protozoa and invertebrates, (iv) environmental conditions, such as water temperature, and (v) spatial location of microorganisms (bulk water, sediment, or biofilm). Water treatment and distribution conditions in water mains and premise plumbing affect each of these factors and shape bacterial community characteristics (abundance, composition, viability) in distribution systems. Improved understanding of bacterial interactions in distribution systems and of environmental conditions impact is needed for better control of bacterial communities during drinking water production and distribution. This article reviews (i) existing knowledge on biological stability controlling factors and (ii) how these factors are affected by drinking water production and distribution conditions. In addition, (iii) the concept of biological stability is discussed in light of experience with well-established and new analytical methods, enabling high throughput analysis and in-depth characterization of bacterial communities in drinking water. We discussed, how knowledge gained from novel techniques will improve design and monitoring of water treatment and distribution systems in order

  3. Biological Stability of Drinking Water: Controlling Factors, Methods, and Challenges

    KAUST Repository

    Prest, Emmanuelle I.

    2016-02-01

    Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and can lead to hygienic (e.g., development of opportunistic pathogens), aesthetic (e.g., deterioration of taste, odor, color) or operational (e.g., fouling or biocorrosion of pipes) problems. Drinking water contains diverse microorganisms competing for limited available nutrients for growth. Bacterial growth and interactions are regulated by factors, such as (i) type and concentration of available organic and inorganic nutrients, (ii) type and concentration of residual disinfectant, (iii) presence of predators, such as protozoa and invertebrates, (iv) environmental conditions, such as water temperature, and (v) spatial location of microorganisms (bulk water, sediment, or biofilm). Water treatment and distribution conditions in water mains and premise plumbing affect each of these factors and shape bacterial community characteristics (abundance, composition, viability) in distribution systems. Improved understanding of bacterial interactions in distribution systems and of environmental conditions impact is needed for better control of bacterial communities during drinking water production and distribution. This article reviews (i) existing knowledge on biological stability controlling factors and (ii) how these factors are affected by drinking water production and distribution conditions. In addition, (iii) the concept of biological stability is discussed in light of experience with well-established and new analytical methods, enabling high throughput analysis and in-depth characterization of bacterial communities in drinking water. We discussed, how knowledge gained from novel techniques will improve design and monitoring of water treatment and distribution systems in order

  4. Preliminary Experimental Analysis of Soil Stabilizers for Contamination Control

    International Nuclear Information System (INIS)

    Lagos, L.; Varona, J.; Zidan, A.; Gudavalli, R.; Wu, Kuang-His

    2006-01-01

    A major focus of Department of Energy's (DOE's) environmental management mission at the Hanford site involves characterizing and remediating contaminated soil and groundwater; stabilizing contaminated soil; remediating disposal sites; decontaminating and decommissioning structures, and demolishing former plutonium production process buildings, nuclear reactors, and separation plants; maintaining inactive waste sites; transitioning facilities into the surveillance and maintenance program; and mitigating effects to biological and cultural resources from site development and environmental cleanup and restoration activities. For example, a total of 470,914 metric tons of contaminated soil from 100 Areas remediation activities were disposed at the Environmental Restoration Disposal Facility (ERDF) during 2004. The Applied Research Center (ARC) at Florida International University (FIU) is supporting the Hanford's site remediation program by analyzing the effectiveness of several soil stabilizers (fixatives) for contamination control during excavation activities. The study is focusing on determining the effects of varying soil conditions, temperature, humidity and wind velocity on the effectiveness of the candidate stabilizers. The test matrix consists of a soil penetration-depth study, wind tunnel experiments for determination of threshold velocity, and temperature and moisture-controlled drying/curing experiments. These three set of experiments are designed to verify performance metrics, as well as provide insight into what fundamental forces are altered by the use of the stabilizer. This paper only presents the preliminary results obtained during wind tunnel experiments using dry Hanford soil samples (with 2.7% moisture by weight). These dry soil samples were exposed to varying wind speeds from 2.22 m/sec to 8.88 m/sec. Furthermore, airborne particulate data was collected for the dry Hanford soil experiments using an aerosol analyzer instrument. (authors)

  5. Caries-preventive effectiveness of fluoride varnish as adjunct to oral health promotion and supervised tooth brushing in preschool children: a double-blind randomized controlled trial.

    Science.gov (United States)

    Agouropoulos, A; Twetman, S; Pandis, N; Kavvadia, K; Papagiannoulis, L

    2014-10-01

    To evaluate the effect of biannual fluoride varnish applications in preschool children as an adjunct to school-based oral health promotion and supervised tooth brushing with 1000ppm fluoride toothpaste. 424 preschool children, 2-5 year of age, from 10 different pre schools in Athens were invited to this double-blind randomized controlled trial and 328 children completed the 2-year programme. All children received oral health education with hygiene instructions twice yearly and attended supervised tooth brushing once daily. The test group was treated with fluoride varnish (0.9% diflurosilane) biannually while the control group had placebo applications. The primary endpoints were caries prevalence and increment; secondary outcomes were gingival health, mutans streptococci growth and salivary buffer capacity. The groups were balanced at baseline and no significant differences in caries prevalence or increment were displayed between the groups after 1 and 2 years, respectively. There was a reduced number of new pre-cavitated enamel lesions during the second year of the study (p=0.05) but the decrease was not statistically significant. The secondary endpoints were unaffected by the varnish treatments. Under the present conditions, biannual fluoride varnish applications in preschool children did not show significant caries-preventive benefits when provided as an adjunct to school-based supervised tooth brushing with 1000ppm fluoride toothpaste. In community based, caries prevention programmes, for high caries risk preschool children, a fluoride varnish may add little to caries prevention, when 1000ppm fluoride toothpaste is used daily. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Effects of a partially supervised conditioning programme in cystic fibrosis: an international multi-centre randomised controlled trial (ACTIVATE-CF): study protocol.

    Science.gov (United States)

    Hebestreit, Helge; Lands, Larry C; Alarie, Nancy; Schaeff, Jonathan; Karila, Chantal; Orenstein, David M; Urquhart, Don S; Hulzebos, Erik H J; Stein, Lothar; Schindler, Christian; Kriemler, Susi; Radtke, Thomas

    2018-02-08

    Physical activity (PA) and exercise have become an accepted and valued component of cystic fibrosis (CF) care. Regular PA and exercise can positively impact pulmonary function, improve physical fitness, and enhance health-related quality of life (HRQoL). However, motivating people to be more active is challenging. Supervised exercise programs are expensive and labour intensive, and adherence falls off significantly once supervision ends. Unsupervised or partially supervised programs are less costly and more flexible, but compliance can be more problematic. The primary objective of this study is to evaluate the effects of a partially supervised exercise intervention along with regular motivation on forced expiratory volume in 1 s (FEV 1 ) at 6 months in a large international group of CF patients. Secondary endpoints include patient reported HRQoL, as well as levels of anxiety and depression, and control of blood sugar. It is planned that a total of 292 patients with CF 12 years and older with a FEV 1  ≥ 35% predicted shall be randomised. Following baseline assessments (2 visits) patients are randomised into an intervention and a control group. Thereafter, they will be seen every 3 months for assessments in their centre for one year (4 follow-up visits). Along with individual counselling to increase vigorous PA by at least 3 h per week on each clinic visit, the intervention group documents daily PA and inactivity time and receives a step counter to record their progress within a web-based diary. They also receive monthly phone calls from the study staff during the first 6 months of the study. After 6 months, they continue with the step counter and web-based programme for a further 6 months. The control group receives standard care and keeps their PA level constant during the study period. Thereafter, they receive the intervention as well. This is the first large, international multi-centre study to investigate the effects of a PA intervention in CF with

  7. Good supervision and PBL

    DEFF Research Database (Denmark)

    Otrel-Cass, Kathrin

    This field study was conducted at the Faculty of Social Sciences at Aalborg University with the intention to investigate how students reflect on their experiences with supervision in a PBL environment. The overall aim of this study was to inform about the continued work in strengthening supervision...... at this faculty. This particular study invited Master level students to discuss: • How a typical supervision process proceeds • How they experienced and what they expected of PBL in the supervision process • What makes a good supervision process...

  8. Man-machine supervision; Supervision homme-machine

    Energy Technology Data Exchange (ETDEWEB)

    Montmain, J. [CEA Valrho, Dir. de l' Energie Nucleaire (DEN), 30 - Marcoule (France)

    2005-05-01

    Today's complexity of systems where man is involved has led to the development of more and more sophisticated information processing systems where decision making has become more and more difficult. The operator task has moved from operation to supervision and the production tool has become indissociable from its numerical instrumentation and control system. The integration of more and more numerous and sophisticated control indicators in the control room does not necessary fulfill the expectations of the operation team. It is preferable to develop cooperative information systems which are real situation understanding aids. The stake is not the automation of operators' cognitive tasks but the supply of a reasoning help. One of the challenges of interactive information systems is the selection, organisation and dynamical display of information. The efficiency of the whole man-machine system depends on the communication interface efficiency. This article presents the principles and specificities of man-machine supervision systems: 1 - principle: operator's role in control room, operator and automation, monitoring and diagnosis, characteristics of useful models for supervision; 2 - qualitative reasoning: origin, trends, evolutions; 3 - causal reasoning: causality, causal graph representation, causal and diagnostic graph; 4 - multi-points of view reasoning: multi flow modeling method, Sagace method; 5 - approximate reasoning: the symbolic numerical interface, the multi-criteria decision; 6 - example of application: supervision in a spent-fuel reprocessing facility. (J.S.)

  9. Duration on the exposure control, spectra storage and texture goniometer handling in the software complex for the accumulation, control and supervising systems at the NSHR and the SKAT spectrometers (Tofa and Goni tasks)

    International Nuclear Information System (INIS)

    Kirilov, A.S.; Korobchenko, M.L.; Sirotin, A.P.; Heinitz, J.

    1997-01-01

    The VME-based accumulation, control and supervising system has been maintained at the NSHR spectrometer since March 1995. Another copy of system has been in use at the newly created SKAT spectrometer since April 1997. This paper is devoted to a detailed description of the user interface for the Join and the Tofa tasks which are dedicated to controlling the duration of the exposure, the spectra storage and handling the texture goniometer at the spectrometers. (author)

  10. Sliding Mode Controller and Lyapunov Redesign Controller to Improve Microgrid Stability

    DEFF Research Database (Denmark)

    Hossain, Eklas; Perez, Ron; Padmanaban, Sanjeevikumar

    2017-01-01

    technique is used to enhance stability of microgrids. Besides adopting this technique here, Sliding Mode Controller (SMC) and Lyapunov Redesign Controller (LRC), two of the most prominent nonlinear control techniques, are individually implemented to control microgrid system stability with desired robustness....... CPL power is then varied to compare robustness of these two control techniques. This investigation revealed the better performance of the LRC system compared to SMC to retain stability in microgrid with dense CPL load. All the necessary results are simulated in Matlab/Simulink platform for authentic......To mitigate the microgrid instability despite the presence of dense Constant Power Load (CPL) loads in the system, a number of compensation techniques have already been gone through extensive research, proposed, and implemented around the world. In this paper, a storage based load side compensation...

  11. Effectiveness of electronic stability control on single-vehicle accidents

    DEFF Research Database (Denmark)

    Lyckegaard, Allan; Hels, Tove; Bernhoft, Inger Marie

    2015-01-01

    the injury severity categories (slight, severe, and fatal). Conclusions: In line with previous results, this study concludes that ESC reduces the risk for single-vehicle injury accidents by 31% when controlling for various confounding factors related to the driver, the car, and the accident surroundings......Objective: This study aims at evaluating the effectiveness of electronic stability control (ESC) on single-vehicle injury accidents while controlling for a number of confounders influencing the accident risk. Methods: Using police-registered injury accidents from 2004 to 2011 in Denmark with cars...... the following were significant. For the driver: Age, gender, driving experience, valid driving license, and seat belt use. For the vehicle: Year of registration, weight, and ESC. For the accident surroundings: Visibility, light, and location. Finally, for the road: Speed limit, surface, and section...

  12. Optimal Control of a Ballast-Stabilized Floating Wind Turbine

    DEFF Research Database (Denmark)

    Christiansen, Søren; Knudsen, Torben; Bak, Thomas

    2011-01-01

    Offshore wind energy capitalizes on the higher and less turbulent wind speeds at sea. The use of floating structures for deeper waters is being explored. The control objective is a tradeoff between power capture and fatigue, especially that produced by the oscillations caused by the reduced...... structural stiffness of a floating installation in combination with a coupling between the fore–aft motion of the tower and the blade pitch. To address this problem, the present paper models a ballast-stabilized floating wind turbine, and suggests a linear quadratic regulator (LQR) in combination with a wind...... estimator and a state observer. The results are simulated using aero elastic code and analysed in terms of damage equivalent loads. When compared to a baseline controller, this controller clearly demonstrates better generator speed and power tracking while reducing fatigue loads....

  13. 32 CFR 631.3 - Supervision.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Supervision. 631.3 Section 631.3 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) LAW ENFORCEMENT AND CRIMINAL INVESTIGATIONS ARMED FORCES DISCIPLINARY CONTROL BOARDS AND OFF-INSTALLATION LIAISON AND OPERATIONS General § 631.3 Supervision. The following will...

  14. 19 CFR 19.34 - Customs supervision.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Customs supervision. 19.34 Section 19.34 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY CUSTOMS WAREHOUSES, CONTAINER STATIONS AND CONTROL OF MERCHANDISE THEREIN Space Bonded for the Storage of Wheat § 19.34 Customs supervision. Port...

  15. Exercise combined with Acceptance and Commitment Therapy (ExACT) compared to a supervised exercise programme for adults with chronic pain: study protocol for a randomised controlled trial.

    Science.gov (United States)

    Casey, Máire-Bríd; Smart, Keith; Segurado, Ricardo; Hearty, Conor; Gopal, Hari; Lowry, Damien; Flanagan, Dearbhail; McCracken, Lance; Doody, Catherine

    2018-03-22

    Acceptance and Commitment Therapy (ACT) is a form of cognitive behavioural therapy, which may be beneficial for people with chronic pain. The approach aims to enhance daily functioning through increased psychological flexibility. Whilst the therapeutic model behind ACT appears well suited to chronic pain, there is a need for further research to test its effectiveness in clinical practice, particularly with regards to combining ACT with physical exercise. This prospective, two-armed, parallel-group, single-centre randomised controlled trial (RCT) will assess the effectiveness of a combined Exercise and ACT programme, in comparison to supervised exercise for chronic pain. One hundred and sixty patients, aged 18 years and over, who have been diagnosed with a chronic pain condition by a physician will be recruited to the trial. Participants will be individually randomised to one of two 8-week, group interventions. The combined group will take part in weekly psychology sessions based on the ACT approach, in addition to supervised exercise classes led by a physiotherapist. The control group will attend weekly supervised exercise classes but will not take part in an ACT programme. The primary outcome will be pain interference at 12-week follow-up, measured using the Brief Pain Inventory-Interference Scale. Secondary outcomes will include self-reported pain severity, self-perception of change, patient satisfaction, quality of life, depression, anxiety and healthcare utilisation. Treatment process measures will include self-efficacy, pain catastrophising, fear avoidance, pain acceptance and committed action. Physical activity will be measured using Fitbit Zip TM activity trackers. Both groups will be followed up post intervention and again after 12 weeks. Estimates of treatment effects at follow-up will be based on an intention-to-treat framework, implemented using a linear mixed-effects model. Individual and focus group qualitative interviews will be undertaken with a

  16. Movement augmentation to evaluate human control of locomotor stability.

    Science.gov (United States)

    Brown, Geoffrey; Wu, Mengnan Mary; Huang, Felix C; Gordon, Keith E

    2017-07-01

    Controlling center of mass (COM) position and velocity within a dynamic base of support is essential for gait stability. This skill is often compromised following neurologic injury, creating a need to develop effective interventions to enhance gait stability. A movement augmentation paradigm applied to walking could potentially be used to improve control of COM dynamics. We have developed a cable robot system, the Agility Trainer, to apply continuous frontal-plane forces to the pelvis during treadmill walking. This cable robot system uses a set of series elastic actuators powered by linear motors to create bilateral forces. Here we use the Agility Trainer to create a negative viscosity force field proportional to the subject's lateral velocity. Two healthy young subjects performed two 10-minute walking trials, Baseline and Negative Viscosity. During the first minute of walking in the Negative Viscosity field, participants' lateral COM motion became less controlled when compared to the rhythmic sinusoidal motion observed during Baseline walking. By the 10th minute of walking in the Negative Viscosity field the participants had adapted their gait patterns, decreasing their variation in peak lateral COM speed each stride. These results demonstrate that it is feasible to use the Agility Trainer to apply a movement augmentation paradigm to human walking.

  17. Stability and vibration control in synchrotron light source buildings

    Energy Technology Data Exchange (ETDEWEB)

    Godel, J.B.

    1991-01-01

    Synchrotron light sources have undergone three generations of development in the last two decades. The National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory has two second generation'' storage rings that currently provide the world's most intense sources of photons in the VUV and X-ray spectral ranges. There are almost 90 beam lines serving a community of 2600 scientists from 370 institutions. They are engaged in basic and applied research in physics, chemistry, biology, medicine, materials science and various technologies. When design of the NSLS began in 1977, emphasis was given to the stability of the concrete slab on which the storage rings and experimental beam lines were placed. Stability is the result of controlling: vibration from sources internal and external to the building, thermal effects of air and water temperature variations, foundation settlement and contact between the slab and underlying subsoil. With the advent of new research where highly focused beams of x-rays must be placed on increasingly smaller targets located 35 meters or more from the source, and the development of x-ray lithography with resolutions approaching 0.1 micron at chip exposure stations, even greater attention to stability is required in building designs. This paper will review the results of the successful NSLS experience and give an integrated design approach that includes elements which contribute to instabilities, and the means available to reduce them to acceptable levels.

  18. Stability and vibration control in synchrotron light source buildings

    Energy Technology Data Exchange (ETDEWEB)

    Godel, J.B.

    1991-12-31

    Synchrotron light sources have undergone three generations of development in the last two decades. The National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory has two ``second generation`` storage rings that currently provide the world`s most intense sources of photons in the VUV and X-ray spectral ranges. There are almost 90 beam lines serving a community of 2600 scientists from 370 institutions. They are engaged in basic and applied research in physics, chemistry, biology, medicine, materials science and various technologies. When design of the NSLS began in 1977, emphasis was given to the stability of the concrete slab on which the storage rings and experimental beam lines were placed. Stability is the result of controlling: vibration from sources internal and external to the building, thermal effects of air and water temperature variations, foundation settlement and contact between the slab and underlying subsoil. With the advent of new research where highly focused beams of x-rays must be placed on increasingly smaller targets located 35 meters or more from the source, and the development of x-ray lithography with resolutions approaching 0.1 micron at chip exposure stations, even greater attention to stability is required in building designs. This paper will review the results of the successful NSLS experience and give an integrated design approach that includes elements which contribute to instabilities, and the means available to reduce them to acceptable levels.

  19. Stability and vibration control in synchrotron light source buildings

    International Nuclear Information System (INIS)

    Godel, J.B.

    1991-01-01

    Synchrotron light sources have undergone three generations of development in the last two decades. The National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory has two ''second generation'' storage rings that currently provide the world's most intense sources of photons in the VUV and X-ray spectral ranges. There are almost 90 beam lines serving a community of 2600 scientists from 370 institutions. They are engaged in basic and applied research in physics, chemistry, biology, medicine, materials science and various technologies. When design of the NSLS began in 1977, emphasis was given to the stability of the concrete slab on which the storage rings and experimental beam lines were placed. Stability is the result of controlling: vibration from sources internal and external to the building, thermal effects of air and water temperature variations, foundation settlement and contact between the slab and underlying subsoil. With the advent of new research where highly focused beams of x-rays must be placed on increasingly smaller targets located 35 meters or more from the source, and the development of x-ray lithography with resolutions approaching 0.1 micron at chip exposure stations, even greater attention to stability is required in building designs. This paper will review the results of the successful NSLS experience and give an integrated design approach that includes elements which contribute to instabilities, and the means available to reduce them to acceptable levels

  20. The effects of Internet-based exercise compared with supervised group exercise in people with type 2 diabetes: a randomized controlled study.

    Science.gov (United States)

    Akinci, Buket; Yeldan, Ipek; Satman, Ilhan; Dirican, Ahmet; Ozdincler, Arzu Razak

    2018-06-01

    To compare the effects of Internet-based exercise on glycaemic control, blood lipids, body composition, physical activity level, functional capacity, and quality of life with supervised group exercise in patients with type 2 diabetes. Single-blind, randomized controlled study. A Faculty of Health Sciences. A total of 65 patients with type 2 diabetes (47 women, 18 men). Group A ( n = 22), control group - physical activity counselling once with a brochure. Group B ( n = 22), supervised group-based exercise, three days per week for eight weeks. Group C ( n = 21), Internet-based exercise following the same programme via a website. Primary outcomes - glycosylated haemoglobin, fasting blood glucose, high-density and low-density lipoprotein, triglyceride, and cholesterol. Secondary outcomes - waist and hip circumferences, body mass index, number of steps, six-minute walking test, and Euro-Quality of Life-5 Dimension. After treatment, glycaemic control (mean change for Group B; Group C; -0.80%, -0.91%, P = 0.003), waist circumference (-4.23 cm, 5.64 cm, P = 0.006), and quality of life (0.26, 0.15, P = 0.013) significantly improved in both training groups compared with the control group. Fasting blood glucose (-46.86 mg/dL, P = 0.009) and hip circumference (-2.7 cm, P = 0.011) were significantly decreased in Group B and total cholesterol (-16.4 mg/dL, P = 0.028), six-minute walking distance (30.5 m, P = 0.01), and number of steps (1258.05, P = 0.023) significantly improved in Group C compared with control group. Group B and Group C changed with equal magnitude. In type 2 diabetes, supervised group-based and Internet-based exercise can improve equally glycaemic control, waist circumference, and quality of life, and both are better than simply counselling.

  1. Plasma control system upgrade and increased plasma stability in NSTX

    Energy Technology Data Exchange (ETDEWEB)

    Mastrovito, D., E-mail: dmastrovito@pppl.go [Princeton Plasma Physics Laboratory, P.O. Box 451 Princeton, NJ 08543 (United States); Gates, D.; Gerhard, S.; Lawson, J.; Ludescher-Furth, C.; Marsala, R. [Princeton Plasma Physics Laboratory, P.O. Box 451 Princeton, NJ 08543 (United States)

    2010-07-15

    Plasma control on the National Spherical Torus Experiment (NSTX) was previously accomplished using eight 333 MHz G4 processors built by Sky computers. Several planned improvements and additional control algorithms required significant upgrades to our real-time control computers and real-time data acquisition infrastructure. Several in-house modules have been designed and implemented including: the digital time stamp module (DITS) and for digital/analog front panel data port (FPDP) output, the FPDP output module digital/analog (FOMD/A). Standard Linux based Intel computers perform the real-time control tasks and InfiniBand as been employed for communication between a user-accessible 'host' server and the real-time computer. In addition to several independent real-time processes the General Atomics developed PCS (Bell (2006) ) system infrastructure continues to be used on NSTX. While maintaining previous functionality, improvements in the control system software include: an RWM feedback algorithm, beta feedback NBI control, more comprehensive error logging and trapping, more user-friendly interface, more complete archiving and restoring functionality, and better status reporting and diagnostic tools. Once completed, we succeeded in increasing overall plasma stability and decreasing control system latency by several times.

  2. Handbook of electrical power system dynamics modeling, stability, and control

    CERN Document Server

    Eremia, Mircea

    2013-01-01

    Complete guidance for understanding electrical power system dynamics and blackouts This handbook offers a comprehensive and up-to-date treatment of power system dynamics. Addressing the full range of topics, from the fundamentals to the latest technologies in modeling, stability, and control, Handbook of Electrical Power System Dynamics provides engineers with hands-on guidance for understanding the phenomena leading to blackouts so they can design the most appropriate solutions for a cost-effective and reliable operation. Focusing on system dynamics, the book details

  3. Burn Control in Fusion Reactors via Nonlinear Stabilization Techniques

    International Nuclear Information System (INIS)

    Schuster, Eugenio; Krstic, Miroslav; Tynan, George

    2003-01-01

    Control of plasma density and temperature magnitudes, as well as their profiles, are among the most fundamental problems in fusion reactors. Existing efforts on model-based control use control techniques for linear models. In this work, a zero-dimensional nonlinear model involving approximate conservation equations for the energy and the densities of the species was used to synthesize a nonlinear feedback controller for stabilizing the burn condition of a fusion reactor. The subignition case, where the modulation of auxiliary power and fueling rate are considered as control forces, and the ignition case, where the controlled injection of impurities is considered as an additional actuator, are treated separately.The model addresses the issue of the lag due to the finite time for the fresh fuel to diffuse into the plasma center. In this way we make our control system independent of the fueling system and the reactor can be fed either by pellet injection or by puffing. This imposed lag is treated using nonlinear backstepping.The nonlinear controller proposed guarantees a much larger region of attraction than the previous linear controllers. In addition, it is capable of rejecting perturbations in initial conditions leading to both thermal excursion and quenching, and its effectiveness does not depend on whether the operating point is an ignition or a subignition point.The controller designed ensures setpoint regulation for the energy and plasma parameter β with robustness against uncertainties in the confinement times for different species. Hence, the controller can increase or decrease β, modify the power, the temperature or the density, and go from a subignition to an ignition point and vice versa

  4. Weakly Supervised Dictionary Learning

    Science.gov (United States)

    You, Zeyu; Raich, Raviv; Fern, Xiaoli Z.; Kim, Jinsub

    2018-05-01

    We present a probabilistic modeling and inference framework for discriminative analysis dictionary learning under a weak supervision setting. Dictionary learning approaches have been widely used for tasks such as low-level signal denoising and restoration as well as high-level classification tasks, which can be applied to audio and image analysis. Synthesis dictionary learning aims at jointly learning a dictionary and corresponding sparse coefficients to provide accurate data representation. This approach is useful for denoising and signal restoration, but may lead to sub-optimal classification performance. By contrast, analysis dictionary learning provides a transform that maps data to a sparse discriminative representation suitable for classification. We consider the problem of analysis dictionary learning for time-series data under a weak supervision setting in which signals are assigned with a global label instead of an instantaneous label signal. We propose a discriminative probabilistic model that incorporates both label information and sparsity constraints on the underlying latent instantaneous label signal using cardinality control. We present the expectation maximization (EM) procedure for maximum likelihood estimation (MLE) of the proposed model. To facilitate a computationally efficient E-step, we propose both a chain and a novel tree graph reformulation of the graphical model. The performance of the proposed model is demonstrated on both synthetic and real-world data.

  5. Co-simulation of heavy truck tire dynamics and electronic stability control systems (phase A).

    Science.gov (United States)

    2009-07-01

    Electronic stability control (ESC) systems have been proven to be an effective means of preventing instability and loss of control on both passenger vehicles and heavy trucks. In addition, roll stability algorithms are an effective means of reducing ...

  6. The problem of the driverless vehicle specified path stability control

    Science.gov (United States)

    Buznikov, S. E.; Endachev, D. V.; Elkin, D. S.; Strukov, V. O.

    2018-02-01

    Currently the effort of many leading foreign companies is focused on creation of driverless transport for transportation of cargo and passengers. Among many practical problems arising while creating driverless vehicles, the problem of the specified path stability control occupies a central place. The purpose of this paper is formalization of the problem in question in terms of the quadratic functional of the control quality, the comparative analysis of the possible solutions and justification of the choice of the optimum technical solution. As square value of the integral of the deviation from the specified path is proposed as the quadratic functional of the control quality. For generation of the set of software and hardware solution variants the Zwicky “morphological box” method is used within the hardware and software environments. The heading control algorithms use the wheel steering angle data and the deviation from the lane centerline (specified path) calculated based on the navigation data and the data from the video system. Where the video system does not detect the road marking, the control is carried out based on the wheel navigation system data and where recognizable road marking exits - based on to the video system data. The analysis of the test results allows making the conclusion that the application of the combined navigation system algorithms that provide quasi-optimum solution of the problem while meeting the strict functional limits for the technical and economic indicators of the driverless vehicle control system under development is effective.

  7. Exponential stability for formation control systems with generalized controllers: A unified approach

    NARCIS (Netherlands)

    Sun, Zhiyong; Mou, Shaoshuai; Anderson, Brian D.O.; Cao, Ming

    2016-01-01

    This paper discusses generalized controllers for distance-based rigid formation shape stabilization and aims to provide a unified approach for the convergence analysis. We consider two types of formation control systems according to different characterizations of target formations: minimally rigid

  8. 76 FR 49532 - Federal Motor Vehicle Safety Standards; Electronic Stability Control; Technical Report on the...

    Science.gov (United States)

    2011-08-10

    ...-0112] Federal Motor Vehicle Safety Standards; Electronic Stability Control; Technical Report on the Effectiveness of Electronic Stability Control Systems for Cars and LTVs AGENCY: National Highway Traffic Safety..., Electronic Stability Control Systems. The report's title is: Crash Prevention Effectiveness in Light-Vehicle...

  9. A comparative study of stabilizing control of a planer electromagnetic levitation using PID and LQR controllers

    Directory of Open Access Journals (Sweden)

    Mundher H.A. Yaseen

    Full Text Available Magnetic levitation is a technique to suspend an object without any mechanical support. The main objective of this study is to demonstrate stabilized closed loop control of 1-DOF Maglev experimentally using real-time control simulink feature of (SIMLAB microcontroller. Proportional Integral Derivative (PID and Linear Quadratic Regulator (LQR controllers are employed to examine the stability performance of the Maglev control system under effect of unbalanced change of load and wave signal on Maglev plane. The effect of unbalanced change of applied load on single point, line and plane are presented. Furthermore, in order to study the effect of sudden change in input signal, the input of wave signal has been applied on all points of the prototype maglev plate simultaneously. The results of pulse width modulation (PWM reveal that the control system using LQR controller provides faster response to adjust the levitated plane comparing to PID controller. Moreover, the air gap distance that controlled using PID controller is rather stable with little oscillation. Meanwhile, LQR controller provided more stability and homogeneous response. Keywords: Magnetic levitation (Maglev, Linear Quadratic Regulator (LQR, PID controller, SIMLAB Platform

  10. Information spread in networks: Games, optimal control, and stabilization

    Science.gov (United States)

    Khanafer, Ali

    This thesis focuses on designing efficient mechanisms for controlling information spread in networks. We consider two models for information spread. The first one is the well-known distributed averaging dynamics. The second model is a nonlinear one that describes virus spread in computer and biological networks. We seek to design optimal, robust, and stabilizing controllers under practical constraints. For distributed averaging networks, we study the interaction between a network designer and an adversary. We consider two types of attacks on the network. In Attack-I, the adversary strategically disconnects a set of links to prevent the nodes from reaching consensus. Meanwhile, the network designer assists the nodes in reaching consensus by changing the weights of a limited number of links in the network. We formulate two problems to describe this competition where the order in which the players act is reversed in the two problems. Although the canonical equations provided by the Pontryagin's Maximum Principle (MP) seem to be intractable, we provide an alternative characterization for the optimal strategies that makes connection to potential theory. Further, we provide a sufficient condition for the existence of a saddle-point equilibrium (SPE) for the underlying zero-sum game. In Attack-II, the designer and the adversary are both capable of altering the measurements of all nodes in the network by injecting global signals. We impose two constraints on both players: a power constraint and an energy constraint. We assume that the available energy to each player is not sufficient to operate at maximum power throughout the horizon of the game. We show the existence of an SPE and derive the optimal strategies in closed form for this attack scenario. As an alternative to the "network designer vs. adversary" framework, we investigate the possibility of stabilizing unknown network diffusion processes using a distributed mechanism, where the uncertainty is due to an attack

  11. Reflecting reflection in supervision

    DEFF Research Database (Denmark)

    Lystbæk, Christian Tang

    associated with reflection and an exploration of alternative conceptions that view reflection within the context of settings which have a more group- and team-based orientation. Drawing on an action research project on health care supervision, the paper questions whether we should reject earlier views...... of reflection, rehabilitate them in order to capture broader connotations or move to new ways of regarding reflection that are more in keeping with not only reflective but also emotive, normative and formative views on supervision. The paper presents a critical perspective on supervision that challenge...... the current reflective paradigm I supervision and relate this to emotive, normative and formative views supervision. The paper is relevant for Nordic educational research into the supervision and guidance...

  12. A comparative study of stabilizing control of a planer electromagnetic levitation using PID and LQR controllers

    Science.gov (United States)

    Yaseen, Mundher H. A.

    Magnetic levitation is a technique to suspend an object without any mechanical support. The main objective of this study is to demonstrate stabilized closed loop control of 1-DOF Maglev experimentally using real-time control simulink feature of (SIMLAB) microcontroller. Proportional Integral Derivative (PID) and Linear Quadratic Regulator (LQR) controllers are employed to examine the stability performance of the Maglev control system under effect of unbalanced change of load and wave signal on Maglev plane. The effect of unbalanced change of applied load on single point, line and plane are presented. Furthermore, in order to study the effect of sudden change in input signal, the input of wave signal has been applied on all points of the prototype maglev plate simultaneously. The results of pulse width modulation (PWM) reveal that the control system using LQR controller provides faster response to adjust the levitated plane comparing to PID controller. Moreover, the air gap distance that controlled using PID controller is rather stable with little oscillation. Meanwhile, LQR controller provided more stability and homogeneous response.

  13. Supervision in banking industry

    OpenAIRE

    Šmída, David

    2012-01-01

    The aim of submitted thesis Supervision in banking is to define the nature and the importance of banking supervision, to justify its existence and to analyze the applicable mechanisms while the system of banking regulation and supervision in this thesis is primarily examined in the European context, with a focus on the Czech Republic. The thesis is divided into five main chapters. The first chapter is devoted to the financial system and the importance of banks in this system, it defines the c...

  14. MULTIPERIOD BANKING SUPERVISION

    OpenAIRE

    KARL-THEODOR EISELE; PHILIPPE ARTZNER

    2013-01-01

    This paper is based on a general method for multiperiod prudential supervision of companies submitted to hedgeable and non-hedgeable risks. Having treated the case of insurance in an earlier paper, we now consider a quantitative approach to supervision of commercial banks. The various elements under supervision are the bank’s current amount of tradeable assets, the deposit amount, and four flow processes: future trading risk exposures, deposit flows, flows of loan repayments and of deposit re...

  15. Rethinking Educational Supervision

    OpenAIRE

    Burhanettin DÖNMEZ; Kadir BEYCİOĞLU

    2009-01-01

    The history of educational (school) supervision has been influenced by the history of the interaction of intellectual movements in politics, society, philosophy and industrial movements. The purpose of this conceptual and theoretical study is to have a brief look at the concept of educational supervision with related historical developments in the field. The paper also intends to see the terms and issues critically, and to conceptualize some issues associated with educational supervision in...

  16. Evaluering af kollegial supervision

    DEFF Research Database (Denmark)

    Petersen, Anne Line Bjerre Folsgaard; Bager, Lene Tortzen; Jørgensen, Mette Eg

    2015-01-01

    Videoen er en evaluering af arbejdet med en metodisk tilgang til kollegial supervision på VIA Ergoterapeutuddannelsen gennem et par år. Evalueringen sætter fokus på selve metoden, der er anvendt til kollegial supervision. Derudover er der fokus på erfaringer og udbytte af at arbejde systematisk med...... kollegial supervision blandt undervisere på VIA Ergoterapeutuddannelsen....

  17. Collective academic supervision

    DEFF Research Database (Denmark)

    Nordentoft, Helle Merete; Thomsen, Rie; Wichmann-Hansen, Gitte

    2013-01-01

    Supervision of students is a core activity in higher education. Previous research on student supervision in higher education focus on individual and relational aspects in the supervisory relationship rather than collective, pedagogical and methodical aspects of the planning of the supervision...... process. This article fills these gaps by discussing potentials and challenges in “Collective Academic Supervision”, a model for supervision at the Master of Education in Guidance at Aarhus University in Denmark. The pedagogical rationale behind the model is that students’ participation and learning...

  18. Australia; Financial System Stability Assessment, including Reports on the Observance of Standards and Codes on the following topics: Banking Supervision, Insurance Regulation, Securities Regulation, and Payment Systems

    OpenAIRE

    International Monetary Fund

    2006-01-01

    The Australian banking system, which holds approximately half of total financial systems assets, and is dominated by four major banks, is sound with high earnings, high asset growth, and low levels of problem assets. Stress tests did not reveal near-term stability concerns, suggesting the banking system is likely to be resilient to adverse shocks. Australia’s financial supervisory structure of prudential authority and market conduct authority is sound overall. The medium-term challenges facin...

  19. On a program manifold's stability of one contour automatic control systems

    Science.gov (United States)

    Zumatov, S. S.

    2017-12-01

    Methodology of analysis of stability is expounded to the one contour systems automatic control feedback in the presence of non-linearities. The methodology is based on the use of the simplest mathematical models of the nonlinear controllable systems. Stability of program manifolds of one contour automatic control systems is investigated. The sufficient conditions of program manifold's absolute stability of one contour automatic control systems are obtained. The Hurwitz's angle of absolute stability was determined. The sufficient conditions of program manifold's absolute stability of control systems by the course of plane in the mode of autopilot are obtained by means Lyapunov's second method.

  20. Stability and linearity control of spectrometric channels of the Cherenkov counters using controllable units

    International Nuclear Information System (INIS)

    Kollar, D.; Kollarova, L.; Khorvat, P.

    1976-01-01

    A system is elaborated to control stability and linearity of the Cherenkov counter spectrometric channels in an experiment on a magnetic monopole search. Linearity of a light characteristic of a photoelectric multiplier is checked with the help of the calibrated light-strikings of light emitting diodes with flare intensity adjusted by controlling generator voltage across the mercury body. A program algorithm is presented for checking stability and linearity of the Cherenkov counter spectrometric channels which helps to consider the fatigue effects of the photoelectric multiplier resulting from the considerable loads

  1. Distributed stability control using intelligent voltage-margin relay

    Energy Technology Data Exchange (ETDEWEB)

    Wiszniewski, A.; Rebizant, W. [Wroclaw Univ. of Technology (Poland); Klimek, A. [Powertech Labs Inc., Surrey, BC (Canada)

    2010-07-01

    This paper presented an intelligent relay that operates if the load to source impedance ratio decreases to a level that is dangerously close to the stability limit, which leads to power system blackouts. The intelligent voltage-margin/difference relay installed at receiving substations automatically initiates action if the voltage stability margin drops to a dangerously low level. The relay decides if the tap changing devices are to be blocked and if under-voltage load shedding should be initiated, thereby mitigating an evolving instability. The intelligent relay has two levels of operation. At the first stage, which corresponds to the higher load to source impedance ratio, the relay initiates blocking of the tap changer. At the second stage, corresponding to the lower source to load impedance ratio, load shedding is initiated. The relay operates when the load to source impedance ratio reaches a certain predetermined level, but it does not depend either on the level of the source voltage or on the difference of source and load impedance phase angles. The algorithm for the relay is relatively simple and uses only locally available signals. Consequently, the transformer is well controlled to eliminate the cases of voltage instability. 6 refs., 7 figs.

  2. Design and Stability of an On-Orbit Attitude Control System Using Reaction Control Thrusters

    Science.gov (United States)

    Hall, Robert A.; Hough, Steven; Orphee, Carolina; Clements, Keith

    2016-01-01

    Basic principles for the design and stability of a spacecraft on-orbit attitude control system employing on-off Reaction Control System (RCS) thrusters are presented. Both vehicle dynamics and the control system actuators are inherently nonlinear, hence traditional linear control system design approaches are not directly applicable. This paper has two main aspects: It summarizes key RCS design principles from earlier NASA vehicles, notably the Space Shuttle and Space Station programs, and introduces advances in the linear modelling and analyses of a phase plane control system derived in the initial development of the NASA's next upper stage vehicle, the Exploration Upper Stage (EUS). Topics include thruster hardware specifications, phase plane design and stability, jet selection approaches, filter design metrics, and RCS rotational maneuver logic.

  3. Stabilizing photoassociated Cs2 molecules by optimal control

    International Nuclear Information System (INIS)

    Zhang Wei; Xie Ting; Huang Yin; Wang Gao-Ren; Cong Shu-Lin

    2013-01-01

    We demonstrate theoretically that photoassociated molecules can be stabilized to deeply bound states. This process is achieved by transferring the population from the outer well to the inner well using the optimal control theory, the Cs 2 molecule is taken as an example. Numerical calculations show that weakly bound molecules formed in the outer well by a pump pulse can be compressed to the inner well via a vibrational level of the ground electronic state as an intermediary by an additionally optimized laser pulse. The positively chirped pulse can enhance the population of the target state. With a transform-limited dump pulse, nearly all the photoassociated molecules in the inner well of the excited electronic state can be transferred to the deeply vibrational level of the ground electronic state. (atomic and molecular physics)

  4. Stability investigation of an airfoil section with active flap control

    DEFF Research Database (Denmark)

    Bergami, Leonardo; Gaunaa, Mac

    2010-01-01

    function approximation. Stability of the full aeroservoelastic system is determined through eigenvalue analysis by state-space formulation of the indicial approximation. Validation is carried out against an implementation of the recursive method by Theodorsen and Garrick for flexure-torsion-aileron flutter...... for fatigue load alleviation. The structural model of the 2-D airfoil section contains three degrees of freedom: heave translation, pitch rotation and flap deflection. A potential flow model provides the aerodynamic forces and their distribution. The unsteady aerodynamics are described using an indicial...... on measurements of either heave displacement, local angle of attack or aerodynamic pressure difference measured over the airfoil. The purpose of the controlled deformable flap is to reduce fluctuations in the aerodynamic forces on the airfoil, which, according to recent studies, have a significant potential...

  5. Stabilizing photoassociated Cs2 molecules by optimal control

    Science.gov (United States)

    Zhang, Wei; Xie, Ting; Huang, Yin; Wang, Gao-Ren; Cong, Shu-Lin

    2013-01-01

    We demonstrate theoretically that photoassociated molecules can be stabilized to deeply bound states. This process is achieved by transferring the population from the outer well to the inner well using the optimal control theory, the Cs2 molecule is taken as an example. Numerical calculations show that weakly bound molecules formed in the outer well by a pump pulse can be compressed to the inner well via a vibrational level of the ground electronic state as an intermediary by an additionally optimized laser pulse. The positively chirped pulse can enhance the population of the target state. With a transform-limited dump pulse, nearly all the photoassociated molecules in the inner well of the excited electronic state can be transferred to the deeply vibrational level of the ground electronic state.

  6. Orbit stability and feedback control in synchrotron radiation rings

    International Nuclear Information System (INIS)

    Yu, L.H.

    1989-01-01

    Stability of the electron orbit is essential for the utilization of a low emittance storage ring as a high brightness radiation source. We discuss the development of the measurement and feedback control of the closed orbit, with emphasis on the activities as the National Synchrotron Light Source of BNL. We discuss the performance of the beam position detectors in use and under development: the PUE rf detector, split ion chamber detector, photo-emission detector, solid state detector, and the graphite detector. Depending on the specific experiments, different beamlines require different tolerances on the orbit motion. Corresponding to these different requirements, we discuss two approaches to closed orbit feedback: the global and local feedback systems. Then we describe a new scheme for the real time global feedback by implementing a feedback system based upon a harmonic analysis of both the orbit movements and the correction magnetic fields. 14 refs., 6 figs., 2 tabs

  7. High level model predictive control for plug-and-play process control with stability guaranty

    DEFF Research Database (Denmark)

    Michelsen, Axel Gottlieb; Stoustrup, Jakob

    2010-01-01

    In this paper a method for designing a stabilizing high level model predictive controller for a hierarchical plug- and-play process is presented. This is achieved by abstracting the lower layers of the controller structure as low order models with uncertainty and by using a robust model predictive...... controller for generating the references for these. A simulation example, in which the actuators in a process control system are changed, is reported to show the potential of this approach for plug and play process control....

  8. Vehicle rollover risk and electronic stability control systems.

    Science.gov (United States)

    MacLennan, P A; Marshall, T; Griffin, R; Purcell, M; McGwin, G; Rue, L W

    2008-06-01

    Electronic stability control (ESC) systems were developed to reduce motor vehicle collisions (MVCs) caused by loss of control. Introduced in Europe in 1995 and in the USA in 1996, ESC is designed to improve vehicle lateral stability by electronically detecting and automatically assisting drivers in unfavorable situations. To examine the relationship between vehicle rollover risk and presence of ESC using a large national database of MVCs. A retrospective cohort study for the period 1995 through 2006 was carried out using data obtained from the National Automotive Sampling System General Estimates System. All passenger cars and sport utility vehicles (SUVs)/vans of model year 1996 and later were eligible. Vehicle ESC (unavailable, optional, standard) was determined on the basis of make, model, and model year. Risk ratios (RRs) and 95% CIs were calculated to compare rollover risk by vehicle ESC group. For all crashes, vehicles equipped with standard ESC had decreased risk of rollover (RR = 0.62, 95% CI 0.50 to 0.77) compared with vehicles with ESC unavailable. The association was consistent for single-vehicle MVCs (RR = 0.61, 95% CI 0.46 to 0.82); passenger cars had decreased rollover risk (RR = 0.77, 95% CI 0.52 to 1.12), but SUVs/vans had a more dramatically decreased risk (RR = 0.40, 95% CI 0.26 to 0.61). This study supports previous results showing ESC to be effective in reducing the risk of rollover. ESC is more effective in SUVs/vans for rollovers related to single-vehicle MVCs.

  9. Landslide Geohazard Monitoring, Early Warning and Stabilization Control Methods

    Science.gov (United States)

    Bednarczyk, Zbigniew

    2014-03-01

    This paper is a presentation of landslide monitoring, early warning and remediation methods recommended for the Polish Carpathians. Instrumentation included standard and automatic on-line measurements with the real-time transfer of data to an Internet web server. The research was funded through EU Innovative Economy Programme and also by the SOPO Landslide Counteraction Project. The landslides investigated were characterized by relatively low rates of the displacements. These ranged from a few millimetres to several centimetres per year. Colluviums of clayey flysch deposits were of a soil-rock type with a very high plasticity and moisture content. The instrumentation consisted of 23 standard inclinometers set to depths of 5-21 m. The starting point of monitoring measurements was in January 2006. These were performed every 1-2 months over the period of 8 years. The measurements taken detected displacements from several millimetres to 40 cm set at a depth of 1-17 m. The modern, on-line monitoring and early warning system was installed in May 2010. The system is the first of its kind in Poland and only one of several such real-time systems in the world. The installation was working with the Local Road Authority in Gorlice. It contained three automatic field stations for investigation of landslide parameters to depths of 12-16 m and weather station. In-place tilt transducers and innovative 3D continuous inclinometer systems with sensors located every 0.5 m were used. It has the possibility of measuring a much greater range of movements compared to standard systems. The conventional and real-time data obtained provided a better recognition of the triggering parameters and the control of geohazard stabilizations. The monitoring methods chosen supplemented by numerical modelling could lead to more reliable forecasting of such landslides and could thus provide better control and landslide remediation possibilities also to stabilization works which prevent landslides.

  10. Landslide Geohazard Monitoring, Early Warning and Stabilization Control Methods

    Directory of Open Access Journals (Sweden)

    Bednarczyk Zbigniew

    2014-03-01

    Full Text Available This paper is a presentation of landslide monitoring, early warning and remediation methods recommended for the Polish Carpathians. Instrumentation included standard and automatic on-line measurements with the real-time transfer of data to an Internet web server. The research was funded through EU Innovative Economy Programme and also by the SOPO Landslide Counteraction Project. The landslides investigated were characterized by relatively low rates of the displacements. These ranged from a few millimetres to several centimetres per year. Colluviums of clayey flysch deposits were of a soil-rock type with a very high plasticity and moisture content. The instrumentation consisted of 23 standard inclinometers set to depths of 5-21 m. The starting point of monitoring measurements was in January 2006. These were performed every 1-2 months over the period of 8 years. The measurements taken detected displacements from several millimetres to 40 cm set at a depth of 1-17 m. The modern, on-line monitoring and early warning system was installed in May 2010. The system is the first of its kind in Poland and only one of several such real-time systems in the world. The installation was working with the Local Road Authority in Gorlice. It contained three automatic field stations for investigation of landslide parameters to depths of 12-16 m and weather station. In-place tilt transducers and innovative 3D continuous inclinometer systems with sensors located every 0.5 m were used. It has the possibility of measuring a much greater range of movements compared to standard systems. The conventional and real-time data obtained provided a better recognition of the triggering parameters and the control of geohazard stabilizations. The monitoring methods chosen supplemented by numerical modelling could lead to more reliable forecasting of such landslides and could thus provide better control and landslide remediation possibilities also to stabilization works which

  11. Stabilization of amorphous calcium carbonate by controlling its particle size

    NARCIS (Netherlands)

    Nudelman, F.; Sonmezler, E.; Bomans, P.H.H.; With, de G.; Sommerdijk, N.A.J.M.

    2010-01-01

    Amorphous calcium carbonate (ACC) nanoparticles of different size are prepared using a flow system. Post-synthesis stabilization with a layer of poly[(a,ß)-DL-aspartic acid] leads to stabilization of the ACC, but only for particles

  12. Fully Closed-Loop Multiple Model Probabilistic Predictive Controller Artificial Pancreas Performance in Adolescents and Adults in a Supervised Hotel Setting.

    Science.gov (United States)

    Forlenza, Gregory P; Cameron, Faye M; Ly, Trang T; Lam, David; Howsmon, Daniel P; Baysal, Nihat; Kulina, Georgia; Messer, Laurel; Clinton, Paula; Levister, Camilla; Patek, Stephen D; Levy, Carol J; Wadwa, R Paul; Maahs, David M; Bequette, B Wayne; Buckingham, Bruce A

    2018-05-01

    Initial Food and Drug Administration-approved artificial pancreas (AP) systems will be hybrid closed-loop systems that require prandial meal announcements and will not eliminate the burden of premeal insulin dosing. Multiple model probabilistic predictive control (MMPPC) is a fully closed-loop system that uses probabilistic estimation of meals to allow for automated meal detection. In this study, we describe the safety and performance of the MMPPC system with announced and unannounced meals in a supervised hotel setting. The Android phone-based AP system with remote monitoring was tested for 72 h in six adults and four adolescents across three clinical sites with daily exercise and meal challenges involving both three announced (manual bolus by patient) and six unannounced (no bolus by patient) meals. Safety criteria were predefined. Controller aggressiveness was adapted daily based on prior hypoglycemic events. Mean 24-h continuous glucose monitor (CGM) was 157.4 ± 14.4 mg/dL, with 63.6 ± 9.2% of readings between 70 and 180 mg/dL, 2.9 ± 2.3% of readings 250 mg/dL. Moderate hyperglycemia was relatively common with 24.6 ± 6.2% of readings between 180 and 250 mg/dL, primarily within 3 h after a meal. Overnight mean CGM was 139.6 ± 27.6 mg/dL, with 77.9 ± 16.4% between 70 and 180 mg/dL, 3.0 ± 4.5% 250 mg/dL. Postprandial hyperglycemia was more common for unannounced meals compared with announced meals (4-h postmeal CGM 197.8 ± 44.1 vs. 140.6 ± 35.0 mg/dL; P < 0.001). No participants met safety stopping criteria. MMPPC was safe in a supervised setting despite meal and exercise challenges. Further studies are needed in a less supervised environment.

  13. Effectiveness of electronic stability control on single-vehicle accidents.

    Science.gov (United States)

    Lyckegaard, Allan; Hels, Tove; Bernhoft, Inger Marie

    2015-01-01

    This study aims at evaluating the effectiveness of electronic stability control (ESC) on single-vehicle injury accidents while controlling for a number of confounders influencing the accident risk. Using police-registered injury accidents from 2004 to 2011 in Denmark with cars manufactured in the period 1998 to 2011 and the principle of induced exposure, 2 measures of the effectiveness of ESC were calculated: The crude odds ratio and the adjusted odds ratio, the latter by means of logistic regression. The logistic regression controlled for a number of confounding factors, of which the following were significant. For the driver: Age, gender, driving experience, valid driving license, and seat belt use. For the vehicle: Year of registration, weight, and ESC. For the accident surroundings: Visibility, light, and location. Finally, for the road: Speed limit, surface, and section characteristics. The present study calculated the crude odds ratio for ESC-equipped cars of getting in a single-vehicle injury accident as 0.40 (95% confidence interval [CI], 0.34-0.47) and the adjusted odds ratio as 0.69 (95% CI, 0.54-0.88). No difference was found in the effectiveness of ESC across the injury severity categories (slight, severe, and fatal). In line with previous results, this study concludes that ESC reduces the risk for single-vehicle injury accidents by 31% when controlling for various confounding factors related to the driver, the car, and the accident surroundings. Furthermore, it is concluded that it is important to control for human factors (at a minimum age and gender) in analyses where evaluations of this type are performed.

  14. An eHealth program versus a standard care supervised health program and associated health outcomes in individuals with mobility disability: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Berglind, Daniel; Nyberg, Gisela; Willmer, Mikaela; Persson, Margareta; Wells, Michael; Forsell, Yvonne

    2018-04-27

    Young adults with mobility disability (MD) are less likely to engage in regular physical activity (PA) compared with their able-bodied peers and inactive adults with a MD are more likely to report one or more chronic diseases compared to those who are physically active. Despite the vast amount of research published in the field of PA interventions over the past decades, little attention has been focused on interventions aiming to increase PA among individuals with MD. Thus, we propose to compare the effects of an eHealth program compared to a usual care supervised health program on levels of PA and other health behaviors. The current intervention will use a randomized controlled trial (RCT) design with two treatment groups (an eHealth program and a usual care supervised health program) in young adults with newly acquired MD. In total, 110 young adults (aged 18-40 years) with a MD, acquired within the past 3 years, will be recruited to participate in a 12-week intervention. The primary study outcome is accelerometer-measured time spent in moderate to vigorous PA. Secondary outcomes includes health-related quality of life, depression, stress, fitness, body composition, diet, musculoskeletal pain, motivation to exercise and work ability. There is a lack of RCTs investigating effective ways to increase levels of PA in young adults with MD. Increased levels of PA among this physically inactive population have the potential to substantially improve health-related outcomes, possibly more so than in the general population. The trial will put strong emphasis on optimizing exercise adherence and investigating feasibility in the two treatment programs. The Ethical Review Board (EPN) at Karolinska Institutet has approved the study (2017/1206-31/1). International Standard Randomised Controlled Trial Number (ISRCTN), reference number ISRCTN22387524 . Prospectively registered February 4, 2018.

  15. Researching online supervision

    DEFF Research Database (Denmark)

    Bengtsen, Søren S. E.; Mathiasen, Helle

    2014-01-01

    Online supervision and the use of digital media in supervisory dialogues is a fast increasing practice in higher education today. However, the concepts in our pedagogical repertoire often reflect the digital tools used for supervision purposes as either a prolongation of the face-to-face contact...

  16. Clinical Supervision in Denmark

    DEFF Research Database (Denmark)

    Jacobsen, Claus Haugaard

    2011-01-01

    Core Questionnaire (DPCCQ) has only few questions on supervision. To rectify this limitation, a recent Danish version of the DPCCQ included two new sections on supervision, one focusing on supervisees and another on supervisors and their supervisory training. This paper presents our initial findings...

  17. Evolution in banking supervision

    OpenAIRE

    Edward J. Stevens

    2000-01-01

    Banking supervision must keep pace with technical innovations in the banking industry. The international Basel Committee on Banking Supervision currently is reviewing public comments on its proposed new method for judging whether a bank maintains enough capital to absorb unexpected losses. This Economic Commentary explains how existing standards became obsolete and describes the new plan.

  18. Forskellighed i supervision

    DEFF Research Database (Denmark)

    Petersen, Birgitte; Beck, Emma

    2009-01-01

    Indtryk og tendenser fra den anden danske konference om supervision, som blev holdt på Københavns Universitet i oktober 2008......Indtryk og tendenser fra den anden danske konference om supervision, som blev holdt på Københavns Universitet i oktober 2008...

  19. Networks of Professional Supervision

    Science.gov (United States)

    Annan, Jean; Ryba, Ken

    2013-01-01

    An ecological analysis of the supervisory activity of 31 New Zealand school psychologists examined simultaneously the theories of school psychology, supervision practices, and the contextual qualities that mediated participants' supervisory actions. The findings indicated that the school psychologists worked to achieve the supervision goals of…

  20. Is it possible to strengthen psychiatric nursing staff's clinical supervision?

    DEFF Research Database (Denmark)

    Gonge, Henrik; Buus, Niels

    2015-01-01

    AIM: To test the effects of a meta-supervision intervention in terms of participation, effectiveness and benefits of clinical supervision of psychiatric nursing staff. BACKGROUND: Clinical supervision is regarded as a central component in developing mental health nursing practices, but the evidence...... an intervention group (n = 40) receiving the meta-supervision in addition to attending usual supervision or to a control group (n = 43) attending usual supervision. METHODS: Self-reported questionnaire measures of clinical supervision effectiveness and benefits were collected at base line in January 2012...... and at follow-up completed in February 2013. In addition, a prospective registration of clinical supervision participation was carried out over 3 months subsequent to the intervention. RESULTS: The main result was that it was possible to motivate staff in the intervention group to participate significantly more...

  1. The LHC string2 supervision system

    CERN Document Server

    Mayya, Y S; Sicard, Claude Henri

    2002-01-01

    This paper describes the implementation of the supervision system for the LHC Prototype Full-Cell also known as String 2. The supervision application is based on a commercial package targeted to industrial controls, but because of the complexity and the specifics of such a system, integration with custom components is necessary in order to merge the industrial requirements with the specificity of the accelerator controls.

  2. Fixed-Time Stability Analysis of Permanent Magnet Synchronous Motors with Novel Adaptive Control

    Directory of Open Access Journals (Sweden)

    Maoxing Liu

    2017-01-01

    Full Text Available We firstly investigate the fixed-time stability analysis of uncertain permanent magnet synchronous motors with novel control. Compared with finite-time stability where the convergence rate relies on the initial permanent magnet synchronous motors state, the settling time of fixed-time stability can be adjusted to desired values regardless of initial conditions. Novel adaptive stability control strategy for the permanent magnet synchronous motors is proposed, with which we can stabilize permanent magnet synchronous motors within fixed time based on the Lyapunov stability theory. Finally, some simulation and comparison results are given to illustrate the validity of the theoretical results.

  3. Electric Vehicle Longitudinal Stability Control Based on a New Multimachine Nonlinear Model Predictive Direct Torque Control

    Directory of Open Access Journals (Sweden)

    M’hamed Sekour

    2017-01-01

    Full Text Available In order to improve the driving performance and the stability of electric vehicles (EVs, a new multimachine robust control, which realizes the acceleration slip regulation (ASR and antilock braking system (ABS functions, based on nonlinear model predictive (NMP direct torque control (DTC, is proposed for four permanent magnet synchronous in-wheel motors. The in-wheel motor provides more possibilities of wheel control. One of its advantages is that it has low response time and almost instantaneous torque generation. Moreover, it can be independently controlled, enhancing the limits of vehicular control. For an EV equipped with four in-wheel electric motors, an advanced control may be envisaged. Taking advantage of the fast and accurate torque of in-wheel electric motors which is directly transmitted to the wheels, a new approach for longitudinal control realized by ASR and ABS is presented in this paper. In order to achieve a high-performance torque control for EVs, the NMP-DTC strategy is proposed. It uses the fuzzy logic control technique that determines online the accurate values of the weighting factors and generates the optimal switching states that optimize the EV drives’ decision. The simulation results built in Matlab/Simulink indicate that the EV can achieve high-performance vehicle longitudinal stability control.

  4. Evaluation of electronic stability control effectiveness in Australasia.

    Science.gov (United States)

    Scully, Jim; Newstead, Stuart

    2008-11-01

    Electronic stability control (ESC) is an in-vehicle technology aimed at improving primary safety by assisting the driver in avoiding loss of control of the vehicle. The aim of this study was to use available crash data from Australia and New Zealand to evaluate the effectiveness of ESC in reducing crash risk and to establish whether benefits estimated from overseas studies have translated to the Australian and New Zealand environments. The sample analysed included 7699 crashed vehicles fitted with ESC which comprised of 90 different models. Poisson regression was used to test whether the differences in the observed and expected crash counts for ESC fitted vehicles were significant, with exposure being induced from counts of rear end impacts. It was found that ESC reduced the risk of single vehicle crashes in which the driver was injured by 68% for 4WDs compared with 27% for passenger cars. The effect of ESC on multiple vehicle crashes in Australia and New Zealand was not clear. The long-term benefits of fitting ESC to all vehicles in Australia were also investigated based on the estimated single vehicle crash reductions.

  5. Car drivers' perceptions of electronic stability control (ESC) systems.

    Science.gov (United States)

    Vadeby, Anna; Wiklund, Mats; Forward, Sonja

    2011-05-01

    As a way to reduce the number of car crashes different in-car safety devices are being introduced. In this paper one such application is being investigated, namely the electronic stability control system (ESC). The study used a survey method, including 2000 private car drivers (1000 driving a car with ESC and 1000 driving a car without ESC). The main objective was to investigate the effect of ESC on driver behaviour. Results show that drivers report that they drive even more carelessly when they believe that they have ESC, than when they do not. Men are more risk prone than women and young drivers more than older drivers. Using the theory of planned behaviour the results show that attitude, subjective norm and perceived control explain between 62% and 67% of driver's variation of intentions to take risks. When descriptive norm was added to the model a small but statistically significant increase was found. The study also shows that more than 35% erroneously believe that their car is equipped with an ESC system. These findings may suggest that driver behaviour could reduce the positive effect ESC has on accidents. It also shows that drivers who purchase a new car are not well informed about what kind of safety devices the car is equipped with. These findings highlight the need for more targeted information to drivers. Copyright © 2010 Elsevier Ltd. All rights reserved.

  6. Supervision of execution of dismantling; Supervision de ejecucion de desmantelamiento

    Energy Technology Data Exchange (ETDEWEB)

    Canizares, J.

    2015-07-01

    Enresa create and organizational structure that covers various areas involved in effective control of Decommissioning Project. One area is the Technical Supervision of Works Decommissioning Project, as Execution Department dependent Technical Management. In the structure, Execution Department acts as liaison between the project, disciplines involved in developing and specialized companies contracted work to achieve your intended target. Equally important is to ensure that such activities are carried out correctly, according to the project documentation. (Author)

  7. Supervised physical exercise to improve the quality of life of cancer patients: the EFICANCER randomised controlled trial.

    Science.gov (United States)

    Sancho, Aintzane; Carrera, Sergio; Arietaleanizbeascoa, Marisol; Arce, Veronica; Gallastegui, Nere Mendizabal; Giné March, Anna; Sanz-Guinea, Aitor; Eskisabel, Araceli; Rodriguez, Ana Lopez; Martín, Rosa A; Lopez-Vivanco, Guillermo; Grandes, Gonzalo

    2015-02-06

    The optimal form of exercise for individuals with cancer has yet to be identified, but there is evidence that exercise improves their quality of life. The aim of this study is to assess the efficacy and efficiency of an innovative physical exercise programme, for individuals undergoing chemotherapy for breast, gastrointestinal or non-small cell lung tumours, for improving quality of life, reducing level of fatigue, and enhancing functional capacity over time. We will conduct a clinical trial in 66 patients with stage IV breast, gastrointestinal or non-small cell lung cancer, recruited by the Department of Oncology of the referral hospital from 4 primary care health centres of the Basque Health Service (Osakidetza). These patients will be randomised to one of two groups. The treatment common to both groups will be the usual care for cancer: optimized usual drug therapies and strengthening of self-care; in addition, patients in the intervention group will participate in a 2-month exercise programme, including both aerobic and strength exercises, supervised by nurses in their health centre. The principal outcome variable is health-related quality of life, measured blindly with the 30-item European Organization for the Research and Treatment of Cancer Core Quality of Life Questionnaire and Short Form-36 four times: at baseline, and 2, 6 and 12 months later. The secondary outcome variables are fatigue (Functional Assessment of Chronic Illness Therapy-Fatigue questionnaire), functional capacity (6-Minute Walk Test and cardiorespiratory test), muscle strength (hand-held dynamometry and sit-to-stand test), radiological response to treatment (Response Evaluation Criteria In Solid Tumors) and progression-free and overall survival. Age, sex, diagnosis, chemotherapy regimen, Eastern Cooperative Oncology Group performance status and smoking status will be considered as predictive variables. Data will be analysed on an intention-to-treat basis, comparing changes at each time

  8. EFFECT OF SUPERVISED MODERATE INTENSITY EXERCISE PROGRAM IN PHASE ONE CARDIAC REHABILITATION OF POST OPERATIVE CABG PATIENTS - A RANDOMIZED CONTROLLED TRAIL

    Directory of Open Access Journals (Sweden)

    Rajan Modi

    2014-10-01

    Full Text Available Background: With the increasing number of cases for CABG, the cardiac rehabilitation has gained importance. The trends in rehabilitation of a coronary artery disease patient are changing by incorporating a variety of aerobic exercises and resisted training in to their rehabilitation program. The outcome of any exercise chiefly depends on the training parameters like intensity, frequency and duration. Hence the present study focused to know the effects of supervised moderate intensity exercises on patients during hospital discharge following CABG. The objective of is to study the effectiveness of supervised moderate intensity exercise on distance walked and Quality of Life at hospital discharge following CABG. Methods: Study recruited randomly 46 patients between age group 40-65 years who were posted for non-emergency CABG for the first time. Pre-operative assessment was done thoroughly and was divided in to two groups, Group A conventional treatment and Group B Moderate intensity exercise group. The patients were treated using different protocols in terms of intensity for 8-10 days immediate post CABG. Then the outcome parameters of 6MWT and sf-36 were compared for analysis. Results: Both groups individually showed extremely significant results for two outcome measures. 6 MWD difference between two treatment groups showed significant results with unpaired t test (t = 8.5720,p<0.001. Quality of life score difference within group showed very significant results but there is no difference found between both groups. Conclusion: Moderate intensity exercises can also be included in the immediate post-operative phase of CABG, as they reduce the length of hospital stay and quicken the cardiac rehabilitation process. But there need to be a lot of randomized control trails to confirm the benefits of moderate intensity exercises in phase one rehabilitation program after CABG.

  9. Spa therapy together with supervised self-mobilisation improves pain, function and quality of life in patients with chronic shoulder pain: a single-blind randomised controlled trial

    Science.gov (United States)

    Chary-Valckenaere, Isabelle; Loeuille, Damien; Jay, Nicolas; Kohler, François; Tamisier, Jean-Noë; Roques, Christian-François; Boulange, Michel; Gay, Gérard

    2018-02-01

    To determine whether spa therapy has a beneficial effect on pain and disability in patients with chronic shoulder pain, this single-blind randomised controlled clinical trial included patients with chronic shoulder pain due to miscellaneous conditions attending one of four spa centres as outpatients. Patients were randomised into two groups: spa therapy (18 days of standardised treatment combining thermal therapy together with supervised mobilisation in a thermal pool) and controls (spa therapy delayed for 6 months: `immediate versus delayed treatment' paradigm). All patients continued usual treatments during the 6-month follow-up period. The main endpoint was the mean change in the French-Quick DASH (F-QD) score at 6 months. The effect size of spa therapy was calculated, and the proportion of patients reaching minimal clinically important improvement (MCII) was compared. Secondary endpoints were the mean change in SF-36, treatment use and tolerance. One hundred eighty-six patients were included (94 patients as controls, 92 in the spa group) and analysed by intention to treat. At 6 months, the mean change in the F-QD score was statistically significantly greater among spa therapy patients than controls (- 32.6 versus - 8.15%; p impact on SF-36 components but not on drug intake. Spa therapy provided a statistically significant benefit on pain, function and quality of life in patients with chronic shoulder pain after 6 months compared with usual care.

  10. Stability and control of wind farms in power systems

    Energy Technology Data Exchange (ETDEWEB)

    Jauch, C.

    2006-10-15

    The Ph.D. project 'Stability and Control of Wind Farms in Power Systems' deals with some selected problems related to wind power in power systems. With increasing wind power penetration, wind turbines substitute the power production of conventional power plants. Therefore, wind turbines also have to take over the power system stabilisation and control tasks, that were traditionally carried out by conventional power plants. Out of the many aspects related to this problem, this project focuses on transient fault ride-through and power system stabilisation. The selection of turbine types considered in this project is limited to active-stall turbines and variable speed, variable pitch turbines with gearboxes and full-scale converter-connected synchronous generators. As a basis for the project, a study into the state of the art is conducted at the beginning of the project. Grid connection requirements that were in force, or published as drafts, at the time, and scientific literature related to the topic, are studied. The project is based on simulations of wind turbines in a power system simulations tool. Some of the models used in this project were readily available prior to the project; the development of others is part of the project. The most extensive modelling work deals with the design of the electrical part of the variable speed turbine and its controls. To simulate realistic grid operation the wind turbine models are connected to an aggregated model of the Nordic power system. For that purpose the Nordic power system model, which was available prior to the project, is extended with a realistic feeder configuration. It is commonly demanded from modern wind turbines, that they must not disconnect in case of transient faults. Therefore, controllers are designed that enable the two turbine types to ride through transient faults. With these transient fault controllers the wind turbines can stay connected to the grid, such that their generation capacity is

  11. Supervision som undervisningsform i voksenspecialundervisningen

    DEFF Research Database (Denmark)

    Kristensen, René

    2000-01-01

    Supervision som undervisningsform i voksenspecialundervisningen. Procesarbejde i undervisning af voksne.......Supervision som undervisningsform i voksenspecialundervisningen. Procesarbejde i undervisning af voksne....

  12. Medical supervision of radiation workers

    International Nuclear Information System (INIS)

    1968-01-01

    The first part of this volume describes the effects of radiation on living organism, both at the overall and at the molecular level. Special attention is paid to the metabolism and toxicity of radioactivity substances. The second part deals with radiological exposure, natural, medical and occupational. The third part provides data on radiological protection standards, and the fourth part addresses the health supervision of workers exposed to ionizing radiation, covering both physical and medical control.

  13. Supervision of execution of dismantling

    International Nuclear Information System (INIS)

    Canizares, J.

    2015-01-01

    Enresa create and organizational structure that covers various areas involved in effective control of Decommissioning Project. One area is the Technical Supervision of Works Decommissioning Project, as Execution Department dependent Technical Management. In the structure, Execution Department acts as liaison between the project, disciplines involved in developing and specialized companies contracted work to achieve your intended target. Equally important is to ensure that such activities are carried out correctly, according to the project documentation. (Author)

  14. Supervised Convolutional Sparse Coding

    KAUST Repository

    Affara, Lama Ahmed

    2018-04-08

    Convolutional Sparse Coding (CSC) is a well-established image representation model especially suited for image restoration tasks. In this work, we extend the applicability of this model by proposing a supervised approach to convolutional sparse coding, which aims at learning discriminative dictionaries instead of purely reconstructive ones. We incorporate a supervised regularization term into the traditional unsupervised CSC objective to encourage the final dictionary elements to be discriminative. Experimental results show that using supervised convolutional learning results in two key advantages. First, we learn more semantically relevant filters in the dictionary and second, we achieve improved image reconstruction on unseen data.

  15. Rethinking Educational Supervision

    Directory of Open Access Journals (Sweden)

    Burhanettin DÖNMEZ

    2009-08-01

    Full Text Available The history of educational (school supervision has been influenced by the history of the interaction of intellectual movements in politics, society, philosophy and industrial movements. The purpose of this conceptual and theoretical study is to have a brief look at the concept of educational supervision with related historical developments in the field. The paper also intends to see the terms and issues critically, and to conceptualize some issues associated with educational supervision in practice. In the paper, the issues are discussed and a number of suggestions are addressed for debate.

  16. Stability Assessment and Tuning of an Adaptively Augmented Classical Controller for Launch Vehicle Flight Control

    Science.gov (United States)

    VanZwieten, Tannen; Zhu, J. Jim; Adami, Tony; Berry, Kyle; Grammar, Alex; Orr, Jeb S.; Best, Eric A.

    2014-01-01

    Recently, a robust and practical adaptive control scheme for launch vehicles [ [1] has been introduced. It augments a classical controller with a real-time loop-gain adaptation, and it is therefore called Adaptive Augmentation Control (AAC). The loop-gain will be increased from the nominal design when the tracking error between the (filtered) output and the (filtered) command trajectory is large; whereas it will be decreased when excitation of flex or sloshing modes are detected. There is a need to determine the range and rate of the loop-gain adaptation in order to retain (exponential) stability, which is critical in vehicle operation, and to develop some theoretically based heuristic tuning methods for the adaptive law gain parameters. The classical launch vehicle flight controller design technics are based on gain-scheduling, whereby the launch vehicle dynamics model is linearized at selected operating points along the nominal tracking command trajectory, and Linear Time-Invariant (LTI) controller design techniques are employed to ensure asymptotic stability of the tracking error dynamics, typically by meeting some prescribed Gain Margin (GM) and Phase Margin (PM) specifications. The controller gains at the design points are then scheduled, tuned and sometimes interpolated to achieve good performance and stability robustness under external disturbances (e.g. winds) and structural perturbations (e.g. vehicle modeling errors). While the GM does give a bound for loop-gain variation without losing stability, it is for constant dispersions of the loop-gain because the GM is based on frequency-domain analysis, which is applicable only for LTI systems. The real-time adaptive loop-gain variation of the AAC effectively renders the closed-loop system a time-varying system, for which it is well-known that the LTI system stability criterion is neither necessary nor sufficient when applying to a Linear Time-Varying (LTV) system in a frozen-time fashion. Therefore, a

  17. Evaluating the effect of innovative motivation and supervision approaches on community health worker performance and retention in Uganda and Mozambique: study protocol for a randomised controlled trial.

    Science.gov (United States)

    Källander, Karin; Strachan, Daniel; Soremekun, Seyi; Hill, Zelee; Lingam, Raghu; Tibenderana, James; Kasteng, Frida; Vassall, Anna; Meek, Sylvia; Kirkwood, Betty

    2015-04-12

    If trained, equipped and utilised, community health workers (CHWs) delivering integrated community case management for sick children can potentially reduce child deaths by 60%. However, it is essential to maintain CHW motivation and performance. The inSCALE project aims to evaluate, using a cluster randomised controlled trial, the effect of interventions to increase CHW supervision and performance on the coverage of appropriate treatment for children with diarrhoea, pneumonia and malaria. Participatory methods were used to identify best practices and innovative solutions. Quantitative community based baseline surveys were conducted to allow restricted randomisation of clusters into intervention and control arms. Individual informed consent was obtained from all respondents. Following formative research and stakeholder consultations, two intervention packages were developed in Uganda and one in Mozambique. In Uganda, approximately 3,500 CHWs in 39 clusters were randomised into a mobile health (mHealth) arm, a participatory community engagement arm and a control arm. In Mozambique, 275 CHWs in 12 clusters were randomised into a mHealth arm and a control arm. The mHealth interventions encompass three components: 1) free phone communication between users; 2) data submission using phones with automated feedback, messages to supervisors for targeted supervision, and online data access for district statisticians; and 3) motivational messages. The community engagement arm in Uganda established village health clubs seeking to 1) improve the status and standing of CHWs, 2) increase demand for health services and 3) communicate that CHWs' work is important. Process evaluation was conducted after 10 months and end-line surveys will establish impact after 12 months in Uganda and 18 months in Mozambique. Main outcomes include proportion of sick children appropriately treated, CHW performance and motivation, and cost effectiveness of interventions. Study strengths include a user

  18. Vehicle handling and stability control by the cooperative control of 4WS and DYC

    Science.gov (United States)

    Shen, Huan; Tan, Yun-Sheng

    2017-07-01

    This paper proposes an integrated control system that cooperates with the four-wheel steering (4WS) and direct yaw moment control (DYC) to improve the vehicle handling and stability. The design works of the four-wheel steering and DYC control are based on sliding mode control. The integration control system produces the suitable 4WS angle and corrective yaw moment so that the vehicle tracks the desired yaw rate and sideslip angle. Considering the change of the vehicle longitudinal velocity that means the comfort of driving conditions, both the driving torque and braking torque are used to generate the corrective yaw moment. Simulation results show the effectiveness of the proposed control algorithm.

  19. Power system stabilizer control for wind power to enhance power system stability

    OpenAIRE

    Domínguez García, José Luís; Gomis Bellmunt, Oriol; Bianchi, Fernando Daniel; Sumper, Andreas

    2011-01-01

    The paper presents a small signal stability analysis for power systems with wind farm interaction. Power systems have damping oscillation modes that can be excited by disturbance or fault in the grid. The power converters of the wind farms can be used to reduce these oscillations and make the system more stable. These ideas are explored to design a power system stabilized (PSS) for a network with conventional generators and a wind farm in order to increase the damping of the oscillation...

  20. Supervision in social work NGOs in Bihor County

    Directory of Open Access Journals (Sweden)

    Cristiana Marcela MARC

    2012-01-01

    Full Text Available This paper presents a qualitative research which aims at analyzing supervision in the social services provided by NGOs in Bihor County. We used the method of sociological investigation by means of interview and data collection was accomplished through the technique of individual semi-structured interview. The obtained responses demonstrate that individual supervision was mostly used and in most cases the professional supervisor was from outside the organization. The respondents considered that supervision reduces professional stress. The main problems encountered in the implementation of supervision are the lack of financial resources and the association of supervision with bureaucratic control.

  1. Aqueous clay suspensions stabilized by alginate fluid gels for coal spontaneous combustion prevention and control.

    Science.gov (United States)

    Qin, Botao; Ma, Dong; Li, Fanglei; Li, Yong

    2017-11-01

    We have developed aqueous clay suspensions stabilized by alginate fluid gels (AFG) for coal spontaneous combustion prevention and control. Specially, this study aimed to characterize the effect of AFG on the microstructure, static and dynamic stability, and coal fire inhibition performances of the prepared AFG-stabilized clay suspensions. Compared with aqueous clay suspensions, the AFG-stabilized clay suspensions manifest high static and dynamic stability, which can be ascribed to the formation of a robust three-dimensional gel network by AFG. The coal acceleration oxidation experimental results show that the prepared AFG-stabilized clay suspensions can improve the coal thermal stability and effectively inhibit the coal spontaneous oxidation process by increasing crossing point temperature (CPT) and reducing CO emission. The prepared low-cost and nontoxic AFG-stabilized clay suspensions, exhibiting excellent coal fire extinguishing performances, indicate great application potentials in coal spontaneous combustion prevention and control.

  2. Supervised Convolutional Sparse Coding

    KAUST Repository

    Affara, Lama Ahmed; Ghanem, Bernard; Wonka, Peter

    2018-01-01

    coding, which aims at learning discriminative dictionaries instead of purely reconstructive ones. We incorporate a supervised regularization term into the traditional unsupervised CSC objective to encourage the final dictionary elements

  3. Supervision and group dynamics

    DEFF Research Database (Denmark)

    Hansen, Søren; Jensen, Lars Peter

    2004-01-01

     An important aspect of the problem based and project organized study at Aalborg University is the supervision of the project groups. At the basic education (first year) it is stated in the curriculum that part of the supervisors' job is to deal with group dynamics. This is due to the experience...... that many students are having difficulties with practical issues such as collaboration, communication, and project management. Most supervisors either ignore this demand, because they do not find it important or they find it frustrating, because they do not know, how to supervise group dynamics...... as well as at Aalborg University. The first visible result has been participating supervisors telling us that the course has inspired them to try supervising group dynamics in the future. This paper will explore some aspects of supervising group dynamics as well as, how to develop the Aalborg model...

  4. Supervision af psykoterapi

    DEFF Research Database (Denmark)

    SUPERVISION AF PSYKOTERAPI indtager en central position i uddannelsen og udviklingen af psykoterapeuter. Trods flere lighedspunkter med psykoterapi, undervisning og konsultation er psykoterapisupervision et selvstændigt virksomhedsområde. Supervisor må foruden at være en trænet psykoterapeut kende...... supervisionens rammer og indplacering i forhold til organisation og samfund. En række kapitler drejer sig om supervisors opgaver, roller og kontrolfunktion, supervision set fra supervisandens perspektiv samt betragtninger over relationer og processer i supervision. Der drøftes fordele og ulemper ved de...... forskellige måder, hvorpå en sag kan fremlægges. Bogens første del afsluttes med refleksioner over de etiske aspekter ved psykoterapisupervision. Bogens anden del handler om de særlige forhold, der gør sig gældende ved supervision af en række specialiserede behandlingsformer eller af psykoterapi med bestemte...

  5. Psykoterapi og supervision

    DEFF Research Database (Denmark)

    Jacobsen, Claus Haugaard

    2014-01-01

    Kapitlet beskriver supervisionen funktioner i forhold til psykoterapi. Supervision af psykoterapi henviser i almindelighed til, at en psykoterapeut konsulterer en ofte mere erfaren kollega (supervisor) med henblik på drøftelse af et konkret igangværende psykoterapeutisk behandlingsforløb. Formålet...... er at fremme denne fagpersons (psykoterapeutens) faglige udvikling samt sikre kvaliteten af behandlingen.kan defineres som i. Der redegøres for, hvorfor supervision er vigtig del af psykoterapeutens profession samt vises, hvorledes supervision foruden den faglige udvikling også er vigtigt redskab i...... psykoterapiens kvalitetssikring. Efter at have drøftet nogle etiske forhold ved supervision, fremlægges endelig nogle få forskningsresultater vedr. psykoterapisupervision af danske psykologer....

  6. HPLC FOR CONTROL STABILITY OF QUERCETIN INJECTABLE DOSAGE FORM

    Directory of Open Access Journals (Sweden)

    Martynov AV

    2016-12-01

    retention time and spectral relations in the UV region from the database of DB-2003 spectrums. HPLC analysis results show that the quercetin is stable in ampouled form under autoclave and storage and freshly diluted quercetin concentrate for infusion are identical. Quercetin aqueous solution which was stored at room temperature for 14 days in the light, turned out to be unstable. It was found that aqueous solutions of polysorbate-80 was full hydrolyzed to the initial compounds. Conclusions In this work the ability of quercetin’s perspective concentrates to be stable were checked. The stability of concentrates was determined by HPLC chromatograph "Millichrome A - 02» (SiChrom, Knauer. It is shown that the HPLC methods can be used to establish the smallest difference in the samples. The quercetin’s non-aqueous concentrate is capable of withstanding retorting and remains in standard indestructible state in nonaqueous media (glycerol, ethanol, polysorbate 80. Quercetin is unstable in aqueous solutions and are destroyed during prolonged storage. HPLC- chromatogram is presented in the article and show that gradient HPLC with UV- detection can be used for quality control of quercetin.

  7. Nonlinear power flow feedback control for improved stability and performance of airfoil sections

    Science.gov (United States)

    Wilson, David G.; Robinett, III, Rush D.

    2013-09-03

    A computer-implemented method of determining the pitch stability of an airfoil system, comprising using a computer to numerically integrate a differential equation of motion that includes terms describing PID controller action. In one model, the differential equation characterizes the time-dependent response of the airfoil's pitch angle, .alpha.. The computer model calculates limit-cycles of the model, which represent the stability boundaries of the airfoil system. Once the stability boundary is known, feedback control can be implemented, by using, for example, a PID controller to control a feedback actuator. The method allows the PID controller gain constants, K.sub.I, K.sub.p, and K.sub.d, to be optimized. This permits operation closer to the stability boundaries, while preventing the physical apparatus from unintentionally crossing the stability boundaries. Operating closer to the stability boundaries permits greater power efficiencies to be extracted from the airfoil system.

  8. Declarative modeling for process supervision

    International Nuclear Information System (INIS)

    Leyval, L.

    1989-01-01

    Our work is a contribution to computer aided supervision of continuous processes. It is inspired by an area of Artificial Intelligence: qualitative physics. Here, supervision is based on a model which continuously provides operators with a synthetic view of the process; but this model is founded on general principles of control theory rather than on physics. It involves concepts such as high gain or small time response. It helps in linking temporally the evolution of various variables. Moreover, the model provides predictions of the future behaviour of the process, which allows action advice and alarm filtering. This should greatly reduce the famous cognitive overload associated to any complex and dangerous evolution of the process

  9. Finite-Time Stabilization and Adaptive Control of Memristor-Based Delayed Neural Networks.

    Science.gov (United States)

    Wang, Leimin; Shen, Yi; Zhang, Guodong

    Finite-time stability problem has been a hot topic in control and system engineering. This paper deals with the finite-time stabilization issue of memristor-based delayed neural networks (MDNNs) via two control approaches. First, in order to realize the stabilization of MDNNs in finite time, a delayed state feedback controller is proposed. Then, a novel adaptive strategy is applied to the delayed controller, and finite-time stabilization of MDNNs can also be achieved by using the adaptive control law. Some easily verified algebraic criteria are derived to ensure the stabilization of MDNNs in finite time, and the estimation of the settling time functional is given. Moreover, several finite-time stability results as our special cases for both memristor-based neural networks (MNNs) without delays and neural networks are given. Finally, three examples are provided for the illustration of the theoretical results.Finite-time stability problem has been a hot topic in control and system engineering. This paper deals with the finite-time stabilization issue of memristor-based delayed neural networks (MDNNs) via two control approaches. First, in order to realize the stabilization of MDNNs in finite time, a delayed state feedback controller is proposed. Then, a novel adaptive strategy is applied to the delayed controller, and finite-time stabilization of MDNNs can also be achieved by using the adaptive control law. Some easily verified algebraic criteria are derived to ensure the stabilization of MDNNs in finite time, and the estimation of the settling time functional is given. Moreover, several finite-time stability results as our special cases for both memristor-based neural networks (MNNs) without delays and neural networks are given. Finally, three examples are provided for the illustration of the theoretical results.

  10. Intensity and frequency stabilization of a laser diode by simultaneously controlling its temperature and current

    Science.gov (United States)

    Mu, Weiwei; Hu, Zhaohui; Wang, Jing; Zhou, Binquan

    2017-10-01

    Nuclear magnetic resonance gyroscope (NMRG) detects the angular velocity of the vehicle utilizing the interaction between the laser beam and the alkali metal atoms along with the noble gas atoms in the alkali vapor cell. In order to reach high precision inertial measurement target, semiconductor laser in NMRG should have good intensity and frequency stability. Generally, laser intensity and frequency are stabilized separately. In this paper, a new method to stabilize laser intensity and frequency simultaneously with double-loop feedback control is presented. Laser intensity is stabilized to the setpoint value by feedback control of laser diode's temperature. Laser frequency is stabilized to the Doppler absorption peak by feedback control of laser diode's current. The feedback control of current is a quick loop, hence the laser frequency stabilize quickly. The feedback control of temperature is a slow loop, hence the laser intensity stabilize slowly. With the feedback control of current and temperature, the laser intensity and frequency are stabilized finally. Additionally, the dependence of laser intensity and frequency on laser diode's current and temperature are analyzed, which contributes to choose suitable operating range for the laser diode. The advantage of our method is that the alkali vapor cell used for stabilizing laser frequency is the same one as the cell used for NMRG to operate, which helps to miniaturize the size of NMRG prototype. In an 8-hour continuous measurement, the long-term stability of laser intensity and frequency increased by two orders of magnitude and one order of magnitude respectively.

  11. Research on food sanitation supervision and risk control of catering industry%餐饮业食品卫生监督与风险控制研究

    Institute of Scientific and Technical Information of China (English)

    何庆国; 吕雪辉; 韩彩凤

    2011-01-01

    目的 应用HACCP原理对餐饮业危害因素进行分析,确定关键控制点,采取强化监督措施,以提高餐饮业卫生质量,保障饮食安全.方法 选择从事食品卫生监督工作1年以上的24名食品卫生监督员.以100家餐馆作为检查对象,对餐馆关键控制点落实情况进行监督,但不处罚,并设置处罚组进行对比.用统计学分析关键控制点的纠偏情况.结果 卫生监督员在日常监督工作中监督重点不明确,工作较粗糙.结论 对卫生监督员的强化培训至关重要;实施干预措施可有效降低餐饮业风险度,加大执法力度,其效果更明显.%Objective Applied HACCP pnnciple to analyze the risk factors of catering industry, determined the essential control point, strengthened surveillance measures, improved catering industry sanitary quality and safeguard diet security. Method To choose 24 food hygiene supervisors who worked more than 1 year and selected 100 restaurants as research objects, and supervised the restaurant essential control point and without punish, set up punishment group to carry on the contrast and used statistics method to analysia. Results Supervision keya were not explicit in daily work of hygienic supervisors, and the work was rough. Conclusions Strengthen training was very important to hygienic supervisors. Implementation intervention measures could effective reduced the catering. industry risk factors, and the effect was obvious when enforced the Laws.

  12. Pitch Motion Stabilization by Propeller Speed Control Using Statistical Controller Design

    DEFF Research Database (Denmark)

    Nakatani, Toshihiko; Blanke, Mogens; Galeazzi, Roberto

    2006-01-01

    This paper describes dynamics analysis of a small training boat and a possibility of ship pitch stabilization by control of propeller speed. After upgrading the navigational system of an actual small training boat, in order to identify the model of the ship, the real data collected by sea trials...... were used for statistical analysis and system identification. This analysis shows that the pitching motion is indeed influenced by engine speed and it is suggested that there exists a possibility of reducing the pitching motion by properly controlling the engine throttle. Based on this observation...

  13. Implementation of Instructional Supervision in Secondary School ...

    African Journals Online (AJOL)

    Science, Technology and Arts Research Journal ... Supervision is critical in the development of any educational program in both developed and ... Clinical Supervision, Collegial Supervision, Self-directive supervision, Informal Supervision etc.

  14. Indian primacy procedures handbook for the public water system supervision (PWSS) program and the underground injection control (UIC) program

    International Nuclear Information System (INIS)

    1993-03-01

    The handbook defines primacy, the responsibilities of primacy, primacy's advantages and limitations, and how to seek primacy. Primacy is a provision in the 1986 Amendments to the Safe Drinking Water Act (SDWA). It allows Indian Tribes the opportunity to assume principal responsibility in the enforcement of public drinking water and/or underground injection control (UIC) regulations within the Indian Tribe's jurisdiction. To attain primacy a Tribe must have drinking water and underground injection control regulations which are at least as strict as EPA regulations, and must have an independent agency or organization within the Tribal government that has the power to enforce its regulations

  15. ATMP-stabilized iron nanoparticles: chelator-controlled nanoparticle synthesis

    Science.gov (United States)

    Greenlee, Lauren F.; Rentz, Nikki S.

    2014-11-01

    In this study, we characterize iron nanoparticles synthesized in water in the presence of a phosphonate chelator, amino tris(methylene phosphonic acid) (ATMP) for a range of molar ratios of ATMP to iron. An increase in the molar ratio from 0.05 to 0.8 decreases nanoparticle size from approximately 150 nm to less than 10 nm. Zeta potential measurements were used to evaluate colloidal stability. Zeta potential values varied as a function of pH, and zeta potential values decreased with increasing pH. At lower molar ratios of ATMP to iron, the zeta potential varied between 15 and -40 mV, passing through an isoelectric point at pH 7.5. At higher ratios, the zeta potential was negative across the measured pH range of 2-12 and varied from -2 to -55 mV. Diffraction analysis indicates that ATMP-stabilized iron nanoparticles may have a nano-crystalline structure, potentially with regions of amorphous iron. Characterization results of ATMP-stabilized iron nanoparticles are compared to results obtained for carboxymethyl cellulose (CMC)-stabilized iron nanoparticles. CMC stabilization caused similar peak broadening in diffraction spectra as for ATMP, suggesting similar nano-crystalline/amorphous structure; however, an increase in the molar ratio of CMC to iron did not cause the same reduction in nanoparticle size as was observed for ATMP-stabilized iron nanoparticles.

  16. Design of Simulation Product for Stability of Electric Power System Using Power System Stabilizer and Optimal Control

    Science.gov (United States)

    Junaidi, Agus; Hamid, K. Abdul

    2018-03-01

    This paper will discuss the use of optimal control and Power System Stabilizer (PSS) in improving the oscillation of electric power system. Oscillations in the electric power system can occur due to the sudden release of the load (Switcing-Off). The oscillation of an unstable system for a long time causes the equipment to work in an interruption. To overcome this problem, a control device is required that can work effectively in repairing the oscillation. The power system is modeled from the Single Machine Infinite Bus Model (SMIB). The state space equation is used to mathematically model SMIB. SMIB system which is a plant will be formed togetherness state variables (State-Space), using riccati equation then determined the optimal gain as controller plant. Plant is also controlled by Power Stabilizer System using phase compensation method. Using Matlab Software based simulation will be observed response of rotor speed change and rotor angle change for each of the two controlling methods. Simulation results using the Simulink-MATLAB 6.1 software will compare the analysis of the plant state in Open loop state and use the controller. The simulation response shows that the optimal control and PSS can improve the stability of the power system in terms of acceleration to achieve settling-time and Over Shoot improvement. From the results of both methods are able to improve system performance.

  17. Stability of a neural predictive controller scheme on a neural model

    DEFF Research Database (Denmark)

    Luther, Jim Benjamin; Sørensen, Paul Haase

    2009-01-01

    In previous works presenting various forms of neural-network-based predictive controllers, the main emphasis has been on the implementation aspects, i.e. the development of a robust optimization algorithm for the controller, which will be able to perform in real time. However, the stability issue....... The resulting controller is tested on a nonlinear pneumatic servo system.......In previous works presenting various forms of neural-network-based predictive controllers, the main emphasis has been on the implementation aspects, i.e. the development of a robust optimization algorithm for the controller, which will be able to perform in real time. However, the stability issue...... has not been addressed specifically for these controllers. On the other hand a number of results concerning the stability of receding horizon controllers on a nonlinear system exist. In this paper we present a proof of stability for a predictive controller controlling a neural network model...

  18. Stabilization

    Directory of Open Access Journals (Sweden)

    Muhammad H. Al-Malack

    2016-07-01

    Full Text Available Fuel oil flyash (FFA produced in power and water desalination plants firing crude oils in the Kingdom of Saudi Arabia is being disposed in landfills, which increases the burden on the environment, therefore, FFA utilization must be encouraged. In the current research, the effect of adding FFA on the engineering properties of two indigenous soils, namely sand and marl, was investigated. FFA was added at concentrations of 5%, 10% and 15% to both soils with and without the addition of Portland cement. Mixtures of the stabilized soils were thoroughly evaluated using compaction, California Bearing Ratio (CBR, unconfined compressive strength (USC and durability tests. Results of these tests indicated that stabilized sand mixtures could not attain the ACI strength requirements. However, marl was found to satisfy the ACI strength requirement when only 5% of FFA was added together with 5% of cement. When the FFA was increased to 10% and 15%, the mixture’s strength was found to decrease to values below the ACI requirements. Results of the Toxicity Characteristics Leaching Procedure (TCLP, which was performed on samples that passed the ACI requirements, indicated that FFA must be cautiously used in soil stabilization.

  19. Stability and performance of propulsion control systems with distributed control architectures and failures

    Science.gov (United States)

    Belapurkar, Rohit K.

    Future aircraft engine control systems will be based on a distributed architecture, in which, the sensors and actuators will be connected to the Full Authority Digital Engine Control (FADEC) through an engine area network. Distributed engine control architecture will allow the implementation of advanced, active control techniques along with achieving weight reduction, improvement in performance and lower life cycle cost. The performance of a distributed engine control system is predominantly dependent on the performance of the communication network. Due to the serial data transmission policy, network-induced time delays and sampling jitter are introduced between the sensor/actuator nodes and the distributed FADEC. Communication network faults and transient node failures may result in data dropouts, which may not only degrade the control system performance but may even destabilize the engine control system. Three different architectures for a turbine engine control system based on a distributed framework are presented. A partially distributed control system for a turbo-shaft engine is designed based on ARINC 825 communication protocol. Stability conditions and control design methodology are developed for the proposed partially distributed turbo-shaft engine control system to guarantee the desired performance under the presence of network-induced time delay and random data loss due to transient sensor/actuator failures. A fault tolerant control design methodology is proposed to benefit from the availability of an additional system bandwidth and from the broadcast feature of the data network. It is shown that a reconfigurable fault tolerant control design can help to reduce the performance degradation in presence of node failures. A T-700 turbo-shaft engine model is used to validate the proposed control methodology based on both single input and multiple-input multiple-output control design techniques.

  20. The Cryogenic Supervision System in NSRRC

    CERN Document Server

    Li, Hsing-Chieh; Chiou, Wen-Song; Hsiao, Feng-Zone; Tsai, Zong-Da

    2005-01-01

    The helium cryogenic system in NSRRC is a fully automatic PLC system using the Siemens SIMATIC 300 controller. Modularization in both hardware and software makes it easy in the program reading, the system modification and the problem debug. Based on the Laview program we had developed a supervision system taking advantage of the Internet technology to get system's real-time information in any place. The functions of this supervision system include the real-time data accessing with more than 300 digital/analog signals, the data restore, the history trend display, and the human machine interface. The data is accessed via a Profibus line connecting the PLC system and the supervision system with a maximum baud rate 1.5 Mbit/s. Due to this supervision system, it is easy to master the status of the cryogenic system within a short time and diagnose the problem.

  1. The conditions for attaining the greatest degree of system stability with strict generator excitation control

    Energy Technology Data Exchange (ETDEWEB)

    Gruzdev, I.A.; Ekimova, M.M.; Truspekova, G.A.

    1982-01-01

    Expressions are derived for an idealized model of a complex electric power system; these expressions define the greatest level of stability of an electric power system and the optimum combination of stabilization factors with automatic excitation control in a single power system. The possibility of increasing the level of stability of an electric power system with simultaneous strict automatic excitation control of the synychronous generators in several power systems is analyzed.

  2. Involvement of trade unions to supervision and control of legislation on labor maintenance in the period of establishment in Ukraine in 1917–1921

    Directory of Open Access Journals (Sweden)

    Галина Василівна Терела

    2017-12-01

    Full Text Available In the article, on the basis of the conducted analysis of the resolutions, instructions, subtitles of the People's Commissariat of Labor of the UkrSSR, the memoranda of the local departments of labor as well-known and for the first time discovered in the archival funds, it was determined that the factory and plant committees and local service committees, being primary centers of All-Russian Central Council of Trade Unions, served as a low authority to legislation on labor legislation maintenance. For this purpose, under the factory committees and trade unions permanent commissions were established for labor protection. The order of the involvement of trade unions to the election of labor (legal, out of district and sanitary labor inspectors, controllers of the People's Committee of state control is analyzed. It was clarified that in practice the involvement of trade unions in the activity of supervision and control bodies in the field of labor was not as active as it was decreed, and was partially replaced by the party representation. It is confirmed that due to proclaimed at the tenth congress of the Russian Communist Party (Bolsheviks the necessity of full transfer of functions on labor protection from the People's Commissariat of Labor to the All-Russian Central Council of Trade Unions, the Labor inspectorate joined the board of trade unions with the preservation of all its state-compulsory functions, including control over the implementation of labor service, the fight against desertion. It is concluded that after the events of 1917, trade unions lost the role of antipodes of state power and began to play the role of its active ally, which stemmed from the class nature of the state of the proletariat, which was declared as a defender of the interests of workers.

  3. Spa therapy together with supervised self-mobilisation improves pain, function and quality of life in patients with chronic shoulder pain: a single-blind randomised controlled trial

    Science.gov (United States)

    Chary-Valckenaere, Isabelle; Loeuille, Damien; Jay, Nicolas; Kohler, François; Tamisier, Jean-Noë; Roques, Christian-François; Boulange, Michel; Gay, Gérard

    2018-06-01

    To determine whether spa therapy has a beneficial effect on pain and disability in patients with chronic shoulder pain, this single-blind randomised controlled clinical trial included patients with chronic shoulder pain due to miscellaneous conditions attending one of four spa centres as outpatients. Patients were randomised into two groups: spa therapy (18 days of standardised treatment combining thermal therapy together with supervised mobilisation in a thermal pool) and controls (spa therapy delayed for 6 months: `immediate versus delayed treatment' paradigm). All patients continued usual treatments during the 6-month follow-up period. The main endpoint was the mean change in the French-Quick DASH (F-QD) score at 6 months. The effect size of spa therapy was calculated, and the proportion of patients reaching minimal clinically important improvement (MCII) was compared. Secondary endpoints were the mean change in SF-36, treatment use and tolerance. One hundred eighty-six patients were included (94 patients as controls, 92 in the spa group) and analysed by intention to treat. At 6 months, the mean change in the F-QD score was statistically significantly greater among spa therapy patients than controls (- 32.6 versus - 8.15%; p < 0.001) with an effect size of 1.32 (95%CI: 0.97-1.68). A significantly greater proportion of spa therapy patients reached MCII (59.3 versus 17.9%). Spa therapy was well tolerated with a significant impact on SF-36 components but not on drug intake. Spa therapy provided a statistically significant benefit on pain, function and quality of life in patients with chronic shoulder pain after 6 months compared with usual care.

  4. Controllability and stability of primary frequency control from thermostatic loads with delays

    DEFF Research Database (Denmark)

    Ziras, Charalampos; Vrettos, Evangelos; You, Shi

    2017-01-01

    There is an increasing interest in exploiting the flexibility of loads to provide ancillary services to the grid. In this paper we study how response delays and lockout constraints affect the controllability of an aggregation of refrigerators offering primary frequency control (PFC). First we...... examine the effect of delays in PFC provision from an aggregation of refrigerators, using a two-area power system. We propose a framework to systematically address frequency measurement and response delays and we determine safe values for the total delays via simulations. We introduce a controllability...... index to evaluate PFC provision under lockout constraints of refrigerators compressors. We conduct extensive simulations to study the effects of measurement delay, ramping times, lockout durations and rotational inertia on the controllability of the aggregation and system stability. Finally, we discuss...

  5. PID self tuning control based on Mamdani fuzzy logic control for quadrotor stabilization

    Energy Technology Data Exchange (ETDEWEB)

    Priyambodo, Tri Kuntoro, E-mail: mastri@ugm.ac.id; Putra, Agfianto Eko [Aerospace and Aeronautics Electronics Research Group, Universitas Gadjah Mada, Yogyakarta (Indonesia); Department of Computer Science and Electronics, Universitas Gadjah Mada, Yogyakarta (Indonesia); Dharmawan, Andi, E-mail: andi-dharmawan@ugm.ac.id [Department of Computer Science and Electronics, Universitas Gadjah Mada, Yogyakarta (Indonesia)

    2016-02-01

    Quadrotor as one type of UAV have the ability to perform Vertical Take Off and Landing (VTOL). It allows the Quadrotor to be stationary hovering in the air. PID (Proportional Integral Derivative) control system is one of the control methods that are commonly used. It is usually used to optimize the Quadrotor stabilization at least based on the three Eulerian angles (roll, pitch, and yaw) as input parameters for the control system. The three constants of PID can be obtained in various methods. The simplest method is tuning manually. This method has several weaknesses. For example if the three constants are not exact, the resulting response will deviate from the desired result. By combining the methods of PID with fuzzy logic systems where human expertise is implemented into the machine language is expected to further optimize the control system.

  6. Strategies for Voltage Control and Transient Stability Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Hiskens, Ian A.

    2013-09-25

    As wind generation grows, its influence on power system performance will becoming increasingly noticeable. Wind generation di ffers from traditional forms of generation in numerous ways though, motivating the need to reconsider the usual approaches to power system assessment and performance enhancement. The project has investigated the impact of wind generation on transient stability and voltage control, identifying and addressing issues at three distinct levels of the power system: 1) at the device level, the physical characteristics of wind turbine generators (WTGs) are quite unlike those of synchronous machines, 2) at the wind-farm level, the provision of reactive support is achieved through coordination of numerous dissimilar devices, rather than straightforward generator control, and 3) from a systems perspective, the location of wind-farms on the sub-transmission network, coupled with the variability inherent in their power output, can cause complex voltage control issues. The project has sought to develop a thorough understanding of the dynamic behaviour of type-3 WTGs, and in particular the WECC generic model. The behaviour of such models is governed by interactions between the continuous dynamics of state variables and discrete events associated with limits. It was shown that these interactions can be quite complex, and may lead to switching deadlock that prevents continuation of the trajectory. Switching hysteresis was proposed for eliminating deadlock situations. Various type-3 WTG models include control blocks that duplicate integrators. It was shown that this leads to non-uniqueness in the conditions governing steady-state, and may result in pre- and post-disturbance equilibria not coinciding. It also gives rise to a zero eigenvalue in the linearized WTG model. In order to eliminate the anomalous behaviour revealed through this investigation, WECC has now released a new generic model for type-3 WTGs. Wind-farms typically incorporate a variety of

  7. Randomized controlled trial of supervised patient self-testing of warfarin therapy using an internet-based expert system.

    LENUS (Irish Health Repository)

    Ryan, F

    2009-08-01

    Increased frequency of prothrombin time testing, facilitated by patient self-testing (PST) of the International Normalized Ratio (INR) can improve the clinical outcomes of oral anticoagulation therapy (OAT). However, oversight of this type of management is often difficult and time-consuming for healthcare professionals. This study reports the first randomized controlled trial of an automated direct-to-patient expert system, enabling remote and effective management of patients on OAT.

  8. Control and supervision of a time projection chamber with GEM readout; Steuerung und Ueberwachung einer Zeitprojektionskammer mit GEM-Auslese

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, David

    2014-02-03

    To get a deeper understanding of the structure of nucleons and the strong interaction binding the constituents inside, the CBELSA/TAPS experiment investigates the resonance spectrum of baryons by meson photoproduction within the scope of the SFB/TRR 16 ''Subnuclear Structure of Matter''. In order to support and expand the physical program, the existing Inner Detector will be replaced by a Time Projection Chamber (TPC) within the next few years. This allows for the detection of charged reaction channels, which can't be measured with the CBELSA/TAPS experiment up to now, as well as for particle identification from the specific energy loss. A First prototype with GEM foils for charge amplification in front of the readout plane and suitable size for the CBELSA/TAPS experiment was built in collaboration with the TU Munich, the detector laboratory of the GSI in Darmstadt and the Stefan-Meyer-Institute of the University Vienna. The TPC has been commissioned successfully within the FOPI experiment at the GSI during several test beam campaigns. Additionally, systematic studies have been carried out with a smaller Test-TPC using a TestBench providing an accurate external track definition. As the electron drift velocity in the TPC volume is a crucial parameter for the exact track reconstruction, detailed simulations of the drift velocity and its dependency on external parameters, such as drift voltage, pressure, gas flow or temperature, have been carried out. The results of these simulations recommend a constant monitoring of all examined parameters to allow a reasonable use of the simulated drift velocities. For this purpose, and to ensure a safe and stable operation of the TPCs and the other detectors on the TestBench, the required hardware, the control software based on a data base and a graphical user interface were designed and constructed as the main part of this work. With this so-called SlowControl, it was possible to measure, control and

  9. STABILITY CONTROL OF ELEVATING-TRANSFER VEHICLES IN THE CONSTRUCTION

    Directory of Open Access Journals (Sweden)

    Zhadanovskiy Boris Vasil’evich

    2016-05-01

    Full Text Available The underground space is widely used in the construction in big cities of the Russian Federation. These works need the use of elevating-transfer vehicles. In this case the requirements of norms and regulations on operating safety should be strictly observed, because their breach often leads to emergency situations and injuries. The organizational and technological solutions when developing the design documentation and executing construction and assembly works should be primarily based on the stability of lifting facilities. The author states the requirements to installation of lifting tackles (cranes. The features of their installation in different operation conditions on construction sites are described. The crane stability depends on many different indicators, which are considered by the author. The calculation algorithms of crane stability are offered.

  10. Settlement Control of Soft Ground using Cement-Ricehusk Stabilization

    Directory of Open Access Journals (Sweden)

    Mokhtar M.

    2012-01-01

    Full Text Available Cement is widely used for improvement of soft soils, but financial and environmental concerns are causing genuine concerns to all parties, leading to the quest for alternative and effective stabilizers. Ricehusk is an agricultural waste in Malaysia, commonly disposed of by open burning or dumping in landfills. Considering that the ashes derived from ricehusk are pozzolanic in nature, there is a possibility that a cement-ricehusk mixture could effectively improve soft soils with reduced cement dosage. This study examines the mixture’s effectiveness by monitoring the settlement reduction in a clay soil. Standard oedometer tests were carried out on a soft marine clay sample admixed with cement-ricehusk. Test specimens contained 0-10% cement and 0-5% of ricehusk respectively, and were left to cure for either seven or 28 days. The stabilized specimens were observed to undergo significant reduction in compressibility, verifying the potential of cement-ricehusk as an alternative soft soil stabilizer.

  11. A preliminary user-friendly, digital console for the control room parameters supervision in old-generation Nuclear Plants

    Energy Technology Data Exchange (ETDEWEB)

    Memmi, F.; Falconi, L.; Cappelli, M.; Palomba, M.; Santoro, E.; Bove, R.; Sepielli, M. [UTFISST, ENEA Casaccia, via Anguillarese 301, Rome (Italy)

    2012-07-01

    Improvements in the awareness of a system status is an essential requirement to achieve safety in every kind of plant. In particular, in the case of Nuclear Power Plants (NPPs), a progress is crucial to enhance the Human Machine Interface (HMI) in order to optimize monitoring and analyzing processes of NPP operational states. Firstly, as old-fashioned plants are concerned, an upgrading of the whole console instrumentation is desirable in order to replace an analog visualization with a full-digital system. In this work, we present a novel instrument able to interface the control console of a nuclear reactor, developed by using CompactRio, a National Instruments embedded architecture and its dedicated programming language. This real-time industrial controller composed by a real-time processor and FPGA modules has been programmed to visualize the parameters coming from the reactor, and to storage and reproduce significant conditions anytime. This choice has been made on the basis of the FPGA properties: high reliability, determinism, true parallelism and re-configurability, achieved by a simple programming method, based on LabVIEW real-time environment. The system architecture exploits the FPGA capabilities of implementing custom timing and triggering, hardware-based analysis and co-processing, and highest performance control algorithms. Data stored during the supervisory phase can be reproduced by loading data from a measurement file, re-enacting worthwhile operations or conditions. The system has been thought to be used in three different modes, namely Log File Mode, Supervisory Mode and Simulation Mode. The proposed system can be considered as a first step to develop a more complete Decision Support System (DSS): indeed this work is part of a wider project that includes the elaboration of intelligent agents and meta-theory approaches. A synoptic has been created to monitor every kind of action on the plant through an intuitive sight. Furthermore, another important

  12. A preliminary user-friendly, digital console for the control room parameters supervision in old-generation Nuclear Plants

    International Nuclear Information System (INIS)

    Memmi, F.; Falconi, L.; Cappelli, M.; Palomba, M.; Santoro, E.; Bove, R.; Sepielli, M.

    2012-01-01

    Improvements in the awareness of a system status is an essential requirement to achieve safety in every kind of plant. In particular, in the case of Nuclear Power Plants (NPPs), a progress is crucial to enhance the Human Machine Interface (HMI) in order to optimize monitoring and analyzing processes of NPP operational states. Firstly, as old-fashioned plants are concerned, an upgrading of the whole console instrumentation is desirable in order to replace an analog visualization with a full-digital system. In this work, we present a novel instrument able to interface the control console of a nuclear reactor, developed by using CompactRio, a National Instruments embedded architecture and its dedicated programming language. This real-time industrial controller composed by a real-time processor and FPGA modules has been programmed to visualize the parameters coming from the reactor, and to storage and reproduce significant conditions anytime. This choice has been made on the basis of the FPGA properties: high reliability, determinism, true parallelism and re-configurability, achieved by a simple programming method, based on LabVIEW real-time environment. The system architecture exploits the FPGA capabilities of implementing custom timing and triggering, hardware-based analysis and co-processing, and highest performance control algorithms. Data stored during the supervisory phase can be reproduced by loading data from a measurement file, re-enacting worthwhile operations or conditions. The system has been thought to be used in three different modes, namely Log File Mode, Supervisory Mode and Simulation Mode. The proposed system can be considered as a first step to develop a more complete Decision Support System (DSS): indeed this work is part of a wider project that includes the elaboration of intelligent agents and meta-theory approaches. A synoptic has been created to monitor every kind of action on the plant through an intuitive sight. Furthermore, another important

  13. On a program manifold’s stability of one contour automatic control systems

    Directory of Open Access Journals (Sweden)

    Zumatov S. S.

    2017-12-01

    Full Text Available Methodology of analysis of stability is expounded to the one contour systems automatic control feedback in the presence of non-linearities. The methodology is based on the use of the simplest mathematical models of the nonlinear controllable systems. Stability of program manifolds of one contour automatic control systems is investigated. The sufficient conditions of program manifold’s absolute stability of one contour automatic control systems are obtained. The Hurwitz’s angle of absolute stability was determined. The sufficient conditions of program manifold’s absolute stability of control systems by the course of plane in the mode of autopilot are obtained by means Lyapunov’s second method.

  14. Optimal supplementary frequency controller design using the wind farm frequency model and controller parameters stability region.

    Science.gov (United States)

    Toulabi, Mohammadreza; Bahrami, Shahab; Ranjbar, Ali Mohammad

    2018-03-01

    In most of the existing studies, the frequency response in the variable speed wind turbines (VSWTs) is simply realized by changing the torque set-point via appropriate inputs such as frequency deviations signal. However, effective dynamics and systematic process design have not been comprehensively discussed yet. Accordingly, this paper proposes a proportional-derivative frequency controller and investigates its performance in a wind farm consisting of several VSWTs. A band-pass filter is deployed before the proposed controller to avoid responding to either steady state frequency deviations or high rate of change of frequency. To design the controller, the frequency model of the wind farm is first characterized. The proposed controller is then designed based on the obtained open loop system. The stability region associated with the controller parameters is analytically determined by decomposing the closed-loop system's characteristic polynomial into the odd and even parts. The performance of the proposed controller is evaluated through extensive simulations in MATLAB/Simulink environment in a power system comprising a high penetration of VSWTs equipped with the proposed controller. Finally, based on the obtained feasible area and appropriate objective function, the optimal values associated with the controller parameters are determined using the genetic algorithm (GA). Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

  15. A comprehensive gaze stabilization controller based on cerebellar internal models

    DEFF Research Database (Denmark)

    Vannucci, Lorenzo; Falotico, Egidio; Tolu, Silvia

    2017-01-01

    . The VOR works in conjunction with the opto-kinetic reflex (OKR), which is a visual feedback mechanism that allows to move the eye at the same speed as the observed scene. Together they keep the image stationary on the retina. In this work we implement on a humanoid robot a model of gaze stabilization...... based on the coordination of VCR and VOR and OKR. The model, inspired by neuroscientific cerebellar theories, is provided with learning and adaptation capabilities based on internal models. We present the results for the gaze stabilization model on three sets of experiments conducted on the SABIAN robot...

  16. Stabilization and tracking controller for a class of nonlinear discrete-time systems

    International Nuclear Information System (INIS)

    Sharma, B.B.; Kar, I.N.

    2011-01-01

    Highlights: → We present recursive design of stabilizing controller for nonlinear discrete-time systems. → Problem of stabilizing and tracking control of single link manipulator system is addressed. → We extend the proposed results to output tracking problems. → The proposed methodology is applied satisfactorily to discrete-time chaotic maps. - Abstract: In this paper, stabilization and tracking control problem for parametric strict feedback class of discrete time systems is addressed. Recursive design of control function based on contraction theory framework is proposed instead of traditional Lyapunov based method. Explicit structure of controller is derived for the addressed class of nonlinear discrete-time systems. Conditions for exponential stability of system states are derived in terms of controller parameters. At each stage of recursive procedure a specific structure of Jacobian matrix is ensured so as to satisfy conditions of stability. The closed loop dynamics in this case remains nonlinear in nature. The proposed algorithm establishes global stability results in quite a simple manner as it does not require formulation of error dynamics. Problem of stabilization and output tracking control in case of single link manipulator system with actuator dynamics is analyzed using the proposed strategy. The proposed results are further extended to stabilization of discrete time chaotic systems. Numerical simulations presented in the end show the effectiveness of the proposed approach.

  17. The beauty of simple adaptive control and new developments in nonlinear systems stability analysis

    Energy Technology Data Exchange (ETDEWEB)

    Barkana, Itzhak, E-mail: ibarkana@gmail.com [BARKANA Consulting, Ramat Hasharon (Israel)

    2014-12-10

    Although various adaptive control techniques have been around for a long time and in spite of successful proofs of stability and even successful demonstrations of performance, the eventual use of adaptive control methodologies in practical real world systems has met a rather strong resistance from practitioners and has remained limited. Apparently, it is difficult to guarantee or even understand the conditions that can guarantee stable operations of adaptive control systems under realistic operational environments. Besides, it is difficult to measure the robustness of adaptive control system stability and allow it to be compared with the common and widely used measure of phase margin and gain margin that is utilized by present, mainly LTI, controllers. Furthermore, customary stability analysis methods seem to imply that the mere stability of adaptive systems may be adversely affected by any tiny deviation from the pretty idealistic and assumably required stability conditions. This paper first revisits the fundamental qualities of customary direct adaptive control methodologies, in particular the classical Model Reference Adaptive Control, and shows that some of their basic drawbacks have been addressed and eliminated within the so-called Simple Adaptive Control methodology. Moreover, recent developments in the stability analysis methods of nonlinear systems show that prior conditions that were customarily assumed to be needed for stability are only apparent and can be eliminated. As a result, sufficient conditions that guarantee stability are clearly stated and lead to similarly clear proofs of stability. As many real-world applications show, once robust stability of the adaptive systems can be guaranteed, the added value of using Add-On Adaptive Control along with classical Control design techniques is pushing the desired performance beyond any previous limits.

  18. DC Microgrids–Part I: A Review of Control Strategies and Stabilization Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Dragicevic, Tomislav; Lu, Xiaonan; Vasquez, Juan; Guerrero, Josep

    2015-01-01

    This paper presents a review of control strategies, stability analysis, and stabilization techniques for dc microgrids (MGs). Overall control is systematically classified into local and coordinated control levels according to respective functionalities in each level. As opposed to local control, which relies only on local measurements, some line of communication between units needs to be made available in order to achieve the coordinated control. Depending on the communication method, three basic coordinated control strategies can be distinguished, i.e., decentralized, centralized, and distributed control. Decentralized control can be regarded as an extension of the local control since it is also based exclusively on local measurements. In contrast, centralized and distributed control strategies rely on digital communication technologies. A number of approaches using these three coordinated control strategies to achieve various control objectives are reviewed in this paper. Moreover, properties of dc MG dynamics and stability are discussed. This paper illustrates that tightly regulated point-of-load converters tend to reduce the stability margins of the system since they introduce negative impedances, which can potentially oscillate with lightly damped power supply input filters. It is also demonstrated that how the stability of the whole system is defined by the relationship of the source and load impedances, referred to as the minor loop gain. Several prominent specifications for the minor loop gain are reviewed. Finally, a number of active stabilization techniques are presented.

  19. Biological stability of drinking water : Controlling factors, methods, and challenges

    NARCIS (Netherlands)

    Prest, E.I.E.D.; Hammes, F.; Van Loosdrecht, M.C.M.; Vrouwenvelder, J.S.

    2016-01-01

    Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and

  20. State Labour Inspectorate – specialized authority exercising supervising and control tasks in the field of labour security and health

    Directory of Open Access Journals (Sweden)

    Nicolae ROMANDAŞ

    2016-06-01

    Full Text Available In present, State Labour Inspectorate is the main supervisory body in health and safety at the work, and has all the rights to exercise an efficient control in order to target the compliance of employers of legal regulations which aim mentioned sphere. Therefore, the mechanism which involves changes in work culture, the most important from of them which refers to security and healthy of work place, take place in our society for harmonization and labor market adjustment. It is obviously that more units start to realize that human resources are most important capital of an organization and is the decisive factor in the production process. That’s why employers should be conscious about the fact that security of an employee it’s not an expanse, but a necessary investment to avoid some costs, direct or indirect caused by work stoppages in the case of a serious and imminent danger or in cases the most unfortunate, the consequences of accidents at work and occupational diseases.

  1. NL(q) Theory: A Neural Control Framework with Global Asymptotic Stability Criteria.

    Science.gov (United States)

    Vandewalle, Joos; De Moor, Bart L.R.; Suykens, Johan A.K.

    1997-06-01

    In this paper a framework for model-based neural control design is presented, consisting of nonlinear state space models and controllers, parametrized by multilayer feedforward neural networks. The models and closed-loop systems are transformed into so-called NL(q) system form. NL(q) systems represent a large class of nonlinear dynamical systems consisting of q layers with alternating linear and static nonlinear operators that satisfy a sector condition. For such NL(q)s sufficient conditions for global asymptotic stability, input/output stability (dissipativity with finite L(2)-gain) and robust stability and performance are presented. The stability criteria are expressed as linear matrix inequalities. In the analysis problem it is shown how stability of a given controller can be checked. In the synthesis problem two methods for neural control design are discussed. In the first method Narendra's dynamic backpropagation for tracking on a set of specific reference inputs is modified with an NL(q) stability constraint in order to ensure, e.g., closed-loop stability. In a second method control design is done without tracking on specific reference inputs, but based on the input/output stability criteria itself, within a standard plant framework as this is done, for example, in H( infinity ) control theory and &mgr; theory. Copyright 1997 Elsevier Science Ltd.

  2. Design of rapid prototype of UAV line-of-sight stabilized control system

    Science.gov (United States)

    Huang, Gang; Zhao, Liting; Li, Yinlong; Yu, Fei; Lin, Zhe

    2018-01-01

    The line-of-sight (LOS) stable platform is the most important technology of UAV (unmanned aerial vehicle), which can reduce the effect to imaging quality from vibration and maneuvering of the aircraft. According to the requirement of LOS stability system (inertial and optical-mechanical combined method) and UAV's structure, a rapid prototype is designed using based on industrial computer using Peripheral Component Interconnect (PCI) and Windows RTX to exchange information. The paper shows the control structure, and circuit system including the inertial stability control circuit with gyro and voice coil motor driven circuit, the optical-mechanical stability control circuit with fast-steering-mirror (FSM) driven circuit and image-deviation-obtained system, outer frame rotary follower, and information-exchange system on PC. Test results show the stability accuracy reaches 5μrad, and prove the effectiveness of the combined line-of-sight stabilization control system, and the real-time rapid prototype runs stable.

  3. Method for supervising and controlling the charging and discharging operations of fuel in a nuclear reactor and apparatus for applying this method

    International Nuclear Information System (INIS)

    Plumier, M.

    1985-01-01

    Method is described for supervising and controlling the charging and discharging operations, in nuclear fuel element assemblies, of a core of a reactor, of a reactor pond and of a decontamination pond, by means of a charging machine equipped with a telescopic mast the end of which is provided with a gripping head with grippers, serving the reactor and the reactor pond in which there is arranged a buffer storage rack, a fixed depositing station and a mobile depositing station, and by means of a charging machine equipped with a telescopic mast the end of which is provided with a gripping head with grippers, serving the decontamination pond containing storage racks, and by means of a transfer device providing communication between the reactor pond and the decontamination pond, characterised in that the initial position in each assembly in the core of the reactor, in the storage racks and possibly in the buffer rack is recorded, in that the position of the charging machine and/or of the handling machine and/or of the transfer device and/or of the mobile depositing station is recorded, likewise the identification of the assembly at the time of each taking up of an assembly and/or at the time of each placing of an assembly in the core of the reactor, in the buffer rack in the transfer basket, in the storage rack, in the fixed depositing station and in the mobile depositing station, in that the command and control signals for each manipulation required of the charging machine, of the handling machine, of the transfer device and of any other mobile station are compared with the recorded signals of a preestablished charging sequence. 5 refs., 4 figs

  4. Prevention of diabetes in overweight/obese children through a family based intervention program including supervised exercise (PREDIKID project): study protocol for a randomized controlled trial.

    Science.gov (United States)

    Arenaza, Lide; Medrano, María; Amasene, María; Rodríguez-Vigil, Beatriz; Díez, Ignacio; Graña, Manuel; Tobalina, Ignacio; Maiz, Edurne; Arteche, Edurne; Larrarte, Eider; Huybrechts, Inge; Davis, Catherine L; Ruiz, Jonatan R; Ortega, Francisco B; Margareto, Javier; Labayen, Idoia

    2017-08-10

    The global pandemic of obesity has led to an increased risk for prediabetes and type-2 diabetes (T2D). The aims of the current project are: (1) to evaluate the effect of a 22-week family based intervention program, including supervised exercise, on insulin resistance syndrome (IRS) risk in children with a high risk of developing T2D and (2) to identify the profile of microRNA in circulating exosomes and in peripheral blood mononuclear cells in children with a high risk of developing T2D and its response to a multidisciplinary intervention program including exercise. A total of 84 children, aged 8-12 years, with a high risk of T2D will be included and randomly assigned to control (N = 42) or intervention (N = 42) groups. The control group will receive a family based lifestyle education and psycho-educational program (2 days/month), while the intervention group will attend the same lifestyle education and psycho-educational program plus the exercise program (3 days/week, 90 min per session including warm-up, moderate to vigorous aerobic activities, and strength exercises). The following measurements will be evaluated at baseline prior to randomization and after the intervention: fasting insulin, glucose and hemoglobin A1c; body composition (dual-energy X-ray absorptiometry); ectopic fat (magnetic resonance imaging); microRNA expression in circulating exosomes and in peripheral blood mononuclear cells (MiSeq; Illumina); cardiorespiratory fitness (cardiopulmonary exercise testing); dietary habits and physical activity (accelerometry). Prevention and identification of children with a high risk of developing T2D could help to improve their cardiovascular health and to reduce the comorbidities associated with obesity. ClinicalTrials.gov, ID: NCT03027726 . Registered on 16 January 2017.

  5. The efficacy of early initiated, supervised, progressive resistance training compared to unsupervised, home-based exercise after unicompartmental knee arthroplasty: a single-blinded randomized controlled trial.

    Science.gov (United States)

    Jørgensen, Peter B; Bogh, Søren B; Kierkegaard, Signe; Sørensen, Henrik; Odgaard, Anders; Søballe, Kjeld; Mechlenburg, Inger

    2017-01-01

    To examine if supervised progressive resistance training was superior to home-based exercise in rehabilitation after unicompartmental knee arthroplasty. Single blinded, randomized clinical trial. Surgery, progressive resistance training and testing was carried out at Aarhus University Hospital and home-based exercise was carried out in the home of the patient. Fifty five patients were randomized to either progressive resistance training or home-based exercise. Patients were randomized to either progressive resistance training (home based exercise five days/week and progressive resistance training two days/week) or control group (home based exercise seven days/week). Preoperative assessment, 10-week (primary endpoint) and one-year follow-up were performed for leg extension power, spatiotemporal gait parameters and knee injury and osteoarthritis outcome score (KOOS). Forty patients (73%) completed 1-year follow-up. Patients in the progressive resistance training group participated in average 11 of 16 training sessions. Leg extension power increased from baseline to 10-week follow-up in progressive resistance training group (progressive resistance training: 0.28 W/kg, P= 0.01, control group: 0.01 W/kg, P=0.93) with no between-group difference. Walking speed and KOOS scores increased from baseline to 10-week follow-up in both groups with no between-group difference (six minutes walk test P=0.63, KOOS P>0.29). Progressive resistance training two days/week combined with home based exercise five days/week was not superior to home based exercise seven days/week in improving leg extension power of the operated leg.

  6. Sync in Complex Dynamical Networks: Stability, Evolution, Control, and Application

    OpenAIRE

    Li, Xiang

    2005-01-01

    In the past few years, the discoveries of small-world and scale-free properties of many natural and artificial complex networks have stimulated significant advances in better understanding the relationship between the topology and the collective dynamics of complex networks. This paper reports recent progresses in the literature of synchronization of complex dynamical networks including stability criteria, network synchronizability and uniform synchronous criticality in different topologies, ...

  7. PI Stabilization for Congestion Control of AQM Routers with Tuning Parameter Optimization

    Directory of Open Access Journals (Sweden)

    S. Chebli

    2016-09-01

    Full Text Available In this paper, we consider the problem of stabilizing network using a new proportional- integral (PI based congestion controller in active queue management (AQM router; with appropriate model approximation in the first order delay systems, we seek a stability region of the controller by using the Hermite- Biehler theorem, which isapplicable to quasipolynomials. A Genetic Algorithm technique is employed to derive optimal or near optimal PI controller parameters.

  8. Bifurcation and stability of an improved time-delayed fluid flow model in internet congestion control

    International Nuclear Information System (INIS)

    Yu-Liang, Liu; Jie, Zhu; Xiao-Shu, Luo

    2009-01-01

    Based on the fluid flow time-delayed model proposed by Misra et al in internet congestion control, one modified time-delayed model is presented, where the influence of the communication delay on the router queue length is investigated in detail. The main advantage of the new model is that its stability domain is larger even without an extra controller. By linear stability analysis and numerical simulation, the effectiveness and feasibility of the novel model in internet congestion control are verified

  9. Bifurcation and stability of an improved time-delayed fluid flow model in internet congestion control

    Science.gov (United States)

    Liu, Yu-Liang; Zhu, Jie; Luo, Xiao-Shu

    2009-09-01

    Based on the fluid flow time-delayed model proposed by Misra et al in internet congestion control, one modified time-delayed model is presented, where the influence of the communication delay on the router queue length is investigated in detail. The main advantage of the new model is that its stability domain is larger even without an extra controller. By linear stability analysis and numerical simulation, the effectiveness and feasibility of the novel model in internet congestion control are verified.

  10. Stabilization and synchronization of Genesio-Tesi system via single variable feedback controller

    International Nuclear Information System (INIS)

    Wang Guangming

    2010-01-01

    This Letter investigates the stabilization and synchronization of Genesio-Tesi systems. Firstly, modifying the previous method, we stabilize the Genesio-Tesi system. Then, we synchronize two identical Genesio chaotic system by extending the obtained stabilization results. To the best of our knowledge, the above controllers obtained in this Letter are simpler than those obtained in the existing results. Finally, numerical simulations verify the effectiveness and the validity of the above theoretical results.

  11. Kontraktetablering i supervision

    DEFF Research Database (Denmark)

    Mortensen, Karen Vibeke; Jacobsen, Claus Haugaard

    2007-01-01

    Kapitlet behandler kontraktetablering i supervision, et element, der ofte er blevet negligeret eller endog helt forbigået ved indledningen af supervisionsforløb. Sikre aftaler om emner som tid, sted, procedurer for fremlæggelse, fortrolighed, ansvarsfordeling og evaluering skaber imidlertid trygh...

  12. Etiske betragtninger ved supervision

    DEFF Research Database (Denmark)

    Jacobsen, Claus Haugaard; Agerskov, Kirsten

    2007-01-01

    Kapitlet præsenterer nogle etiske betragtninger ved supervision. Mens der længe har eksisteret etiske retningslinjer for psykoterapeutisk arbejde, har der overraskende nok manglet tilsvarende vejledninger på supervisionsområdet. Det betyder imidlertid ikke, at de ikke er relevante. I kapitlet gøres...

  13. Effectiveness of Group Supervision versus Combined Group and Individual Supervision.

    Science.gov (United States)

    Ray, Dee; Altekruse, Michael

    2000-01-01

    Investigates the effectiveness of different types of supervision (large group, small group, combined group, individual supervision) with counseling students (N=64). Analyses revealed that all supervision formats resulted in similar progress in counselor effectiveness and counselor development. Participants voiced a preference for individual…

  14. Study of fuzzy adaptive PID controller on thermal frequency stabilizing laser with double longitudinal modes

    Science.gov (United States)

    Mo, Qingkai; Zhang, Tao; Yan, Yining

    2016-10-01

    There are contradictions among speediness, anti-disturbance performance, and steady-state accuracy caused by traditional PID controller in the existing light source systems of thermal frequency stabilizing laser with double longitudinal modes. In this paper, a new kind of fuzzy adaptive PID controller was designed by combining fuzzy PID control technology and expert system to make frequency stabilizing system obtain the optimal performance. The experiments show that the frequency stability of the designed PID controller is similar to the existing PID controller (the magnitude of frequency stability is less than 10-9 in constant temperature and 10-7 in open air). But the preheating time is shortened obviously (from 10 minutes to 5 minutes) and the anti-disturbance capability is improved significantly (the recovery time needed after strong interference is reduced from 1 minute to 10 seconds).

  15. Impacts of P-f & Q-V Droop Control on MicroGrids Transient Stability

    Science.gov (United States)

    Zhao-xia, Xiao; Hong-wei, Fang

    Impacts of P-f & Q-V droop control on MicroGrid transient stability was investigated with a wind unit of asynchronous generator in the MicroGrid. The system frequency stability was explored when the motor load starts and its load power changes, and faults of different types and different locations occurs. The simulations were done by PSCAD/EMTDC.

  16. The effectiveness of core stabilization exercise in adolescent idiopathic scoliosis: A randomized controlled trial.

    Science.gov (United States)

    Gür, Gözde; Ayhan, Cigdem; Yakut, Yavuz

    2017-06-01

    Core stabilization training is used to improve postural balance in musculoskeletal problems. The purpose of this study was to investigate the effectiveness of stabilization training in adolescent idiopathic scoliosis. A randomized controlled trial, pretest-posttest design. In total, 25 subjects with adolescent idiopathic scoliosis were randomly divided into two groups: stabilization group ( n = 12) and control group ( n = 13). The stabilization group received core stabilization in addition to traditional rehabilitation, and the control group received traditional rehabilitation for 10 weeks. Assessment included Cobb's angle on radiograph, apical vertebral rotation in Adam's test, trunk asymmetry (Posterior Trunk Symmetry Index), cosmetic trunk deformity (Trunk Appearance Perception Scale), and quality of life (Scoliosis Research Society-22 questionnaire). Inter-group comparisons showed significantly greater improvements in the mean change in lumbar apical vertebral rotation degree and the pain domain of Scoliosis Research Society-22 in the stabilization group than those in the control group ( p adolescent idiopathic scoliosis. Clinical relevance Stabilization exercises are more effective in reducing rotation deformity and pain than traditional exercises in the conservative rehabilitation of adolescent idiopathic scoliosis. These improvements suggest that stabilization training should be added to rehabilitation programs in adolescent idiopathic scoliosis.

  17. An analysis of the stability and monotonicity of a kind of control models

    Directory of Open Access Journals (Sweden)

    LU Yifa

    2013-06-01

    Full Text Available The stability and monotonicity of control systems with parameters are considered.By the iterative relationship of the coefficients of characteristic polynomials and the Mathematica software,some sufficient conditions for the monotonicity and stability of systems are given.

  18. The Absolute Stability Analysis in Fuzzy Control Systems with Parametric Uncertainties and Reference Inputs

    Science.gov (United States)

    Wu, Bing-Fei; Ma, Li-Shan; Perng, Jau-Woei

    This study analyzes the absolute stability in P and PD type fuzzy logic control systems with both certain and uncertain linear plants. Stability analysis includes the reference input, actuator gain and interval plant parameters. For certain linear plants, the stability (i.e. the stable equilibriums of error) in P and PD types is analyzed with the Popov or linearization methods under various reference inputs and actuator gains. The steady state errors of fuzzy control systems are also addressed in the parameter plane. The parametric robust Popov criterion for parametric absolute stability based on Lur'e systems is also applied to the stability analysis of P type fuzzy control systems with uncertain plants. The PD type fuzzy logic controller in our approach is a single-input fuzzy logic controller and is transformed into the P type for analysis. In our work, the absolute stability analysis of fuzzy control systems is given with respect to a non-zero reference input and an uncertain linear plant with the parametric robust Popov criterion unlike previous works. Moreover, a fuzzy current controlled RC circuit is designed with PSPICE models. Both numerical and PSPICE simulations are provided to verify the analytical results. Furthermore, the oscillation mechanism in fuzzy control systems is specified with various equilibrium points of view in the simulation example. Finally, the comparisons are also given to show the effectiveness of the analysis method.

  19. Brezzi-Pitkaranta stabilization and a priori error analysis for the Stokes Control

    Directory of Open Access Journals (Sweden)

    Aytekin Cibik

    2016-12-01

    Full Text Available In this study, we consider a Brezzi-Pitkaranta stabilization scheme for the optimal control problem governed by stationary Stokes equation, using a P1-P1 interpolation for velocity and pressure. We express the stabilization as extra terms added to the discrete variational form of the problem.  We first prove the stability of the finite element discretization of the problem. Then, we derive a priori error bounds for each variable and present a numerical example to show the effectiveness of the stabilization clearly.

  20. EFFECTS OF INDIVIDUAL CHARACTERISTICS AND ORGANIZATIONAL CONTEXT ON SUPERIORS' USE OF CONFLICT STYLES AND SUBORDINATES' SATISFACTION WITH SUPERVISION

    Directory of Open Access Journals (Sweden)

    Lee Kim Lian

    2008-01-01

    Full Text Available Data from 139 respondents from major industries showed that subordinates were more satisfied with their superiors' supervision through the exercise of integrating, compromising and obliging styles. On the contrary, subordinates who perceived their superiors as primarily using dominating and avoiding styles viewed them as incompetent in supervision and thus lowering their level of satisfaction with supervision. Among the conflict handling styles, integrating was most correlated with organic structure. The organic structure was found to be positively correlated with subordinates' satisfaction. These results implied that organic structure can be a potent force in maintaining organizational stability. The exercise of dominating style was found to be only marginally correlated with superior's age. Superior rank in lower hierarchy level was found to have a negative impact, albeit marginally on the exercise of dominating style. The present results also seemed to suggest that subordinates tend to be less satisfied with superiors with wider span of control.

  1. Effects of supervised exercise and dietary nitrate in older adults with controlled hypertension and/or heart failure with preserved ejection fraction.

    Science.gov (United States)

    Shaltout, Hossam A; Eggebeen, Joel; Marsh, Anthony P; Brubaker, Peter H; Laurienti, Paul J; Burdette, Jonathan H; Basu, Swati; Morgan, Ashley; Dos Santos, Patricia C; Norris, James L; Morgan, Timothy M; Miller, Gary D; Rejeski, W Jack; Hawfield, Amret T; Diz, Debra I; Becton, J Thomas; Kim-Shapiro, Daniel B; Kitzman, Dalane W

    2017-09-30

    Aerobic exercise training is an effective therapy to improve peak aerobic power (peak VO 2 ) in individuals with hypertension (HTN, AHA/ACC class A) and heart failure patients with preserved ejection fraction (HFpEF). High nitrate containing beetroot juice (BRJ) also improves sub-maximal endurance and decreases blood pressure in both HTN and HFpEF. We hypothesized that combining an aerobic exercise and dietary nitrate intervention would result in additive or even synergistic positive effects on exercise tolerance and blood pressure in HTN or HFpEF. We report results from two pilot studies examining the effects of supervised aerobic exercise combined with dietary nitrate in patients with controlled HTN (n = 26, average age 65 ± 5 years) and in patients with HFpEF (n = 20, average age 69 ± 7 years). All patients underwent an aerobic exercise training regimen; half were randomly assigned to consume a high nitrate-containing beet juice beverage (BRJ containing 6.1 mmol nitrate for the HFpEF study consumed three times a week and 8 mmol nitrate for the HTN study consumed daily) while the other half consumed a beet juice beverage with the nitrate removed (placebo). The main result was that there was no added benefit observed for any outcomes when comparing BRJ to placebo in either HTN or HFpEF patients undergoing exercise training (p ≥ 0.14). There were within-group benefits. In the pilot study in patients with HFpEF, aerobic endurance (primary outcome), defined as the exercise time to volitional exhaustion during submaximal cycling at 75% of maximal power output, improved during exercise training within each group from baseline to end of study, 369 ± 149 s vs 520 ± 257 s (p = 0.04) for the placebo group and 384 ± 129 s vs 483 ± 258 s for the BRJ group (p = 0.15). Resting systolic blood pressure in patients with HFpEF also improved during exercise training in both groups, 136 ± 16 mm Hg vs 122 ± 3 mm Hg for the placebo group (p

  2. Multimodal supervision programme to reduce catheter associated urinary tract infections and its analysis to enable focus on labour and cost effective infection control measures in a tertiary care hospital in India.

    Science.gov (United States)

    Jaggi, Namita; Sissodia, Pushpa

    2012-10-01

    Catheter Associated Urinary Tract Infections (CAUTI) contribute 30%-40% of all the nosocomial infections and they are associated with substantially increased institutional death rates. A multimodal supervision program which incorporates training of the staff with respect to infection control measures can be effective in reducing the CAUTIs in hospitals. To assess the impact of a multimodal UTI supervision program on the CAUTI rates over a year, from January 2009 to December 2009, in a tertiary care hospital in India. A 215 bedded tertiary care private hospital. The CAUTI rates were analyzed for the first 6 months (January 2009-June 2009). A UTI supervision program was instituted in the month of July 2009, which included training with respect to the standard protocols for the sample collection and diagnosis, the bundle components of the urinary catheter checklist and hand hygiene practices. The impact was assessed as per the CAUTI rates in the subsequent months. The average CAUTI rate was reduced by 47.1% (from 10.6 to 5.6) after the introduction of the supervision program. This study presented the mean age of the patients with CAUTIs as 54.5 years and it showed an approximately equal contribution of both the sexes (52.94% in males and 47.05% in females). The impact analysis of the supervision program showed a reduction of 8.7% (from 23 days to 21 days) during the average duration of the catheterization. The adherence to the components of the urinary catheter check list was increased by 44.4% (p=0.069) and the hand hygiene compliance was increased by 56.4% (p=0.004) respectively after the interventions. Components like bladder irrigation and practising perineal cleaning were found to show no effect on the CAUTI rates. The most common labour and cost effective infection control measures as revealed by the supervision programme were adherence to the urinary catheter checklist components (indication for catheter insertion and change, asepsis maintenance during and

  3. Attitude Stabilization Control of a Quadrotor UAV by Using Backstepping Approach

    Directory of Open Access Journals (Sweden)

    Xing Huo

    2014-01-01

    Full Text Available The modeling and attitude stabilization control problems of a four-rotor vertical takeoff and landing unmanned air vehicle (UAV known as the quadrotor are investigated. The quadrotor’s attitude is represented by the unit quaternion rather than Euler angles to avoid singularity problem. Taking dynamical behavior of motors into consideration and ignoring aerodynamic effect, a nonlinear controller is developed to stabilize the attitude. The control design is accomplished by using backstepping control technique. The proposed control law is based on the compensation for the Coriolis and gyroscope torques. Applying Lyapunov stability analysis proves that the closed-loop attitude system is asymptotic stable. Moreover, the controller can guarantee that all the states of the system are uniformly ultimately bounded in the presence of external disturbance torque. The effectiveness of the proposed control approach is analytically authenticated and also validated via simulation study.

  4. Wide area stability analysis and control of interconnected power systems with HVDC and FACTS devices

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yong

    2012-11-01

    In order to damp low-frequency oscillations and improve the overall stability of large-scale interconnected power systems, this book investigates the wide-area stability analysis and control methods from different perspectives. The flexible and fast control capability of high-voltage (FACTS) is investigated in detail to implement a wide-area measurement based damping control. A sequential and global mixed optimization method is proposed to simultaneously optimize local and wide area damping controllers. A wide-area robust coordination method is presented to coordinate multiple wide-area damping controllers (WADC). A delay-dependent robust design method is also proposed to handle time-varying delays commonly existing in wide-area signal communication. A closed-loop hardware experiment is used to validate the damping performance. The research activities of this book include power system stability analysis and control, wide-area damping control as well as HVDC and FACTS technologies.

  5. Positive polynomials and robust stabilization with fixed-order controllers

    Czech Academy of Sciences Publication Activity Database

    Henrion, Didier; Šebek, M.; Kučera, V.

    2003-01-01

    Roč. 48, č. 7 (2003), s. 1178-1186 ISSN 0018-9286 R&D Projects: GA ČR GA102/02/0709; GA MŠk ME 496 Institutional research plan: CEZ:AV0Z1075907 Keywords : fixed-order control lers * linear matrix inequality * polynomials, robust control Subject RIV: BC - Control Systems Theory Impact factor: 1.896, year: 2003

  6. Developing a manual for strengthening mental health nurses' clinical supervision

    DEFF Research Database (Denmark)

    Buus, Niels; Cassedy, Paul; Gonge, Henrik

    2013-01-01

    In this article, we report findings from a study aimed at developing the content and implementation of a manual for a research-based intervention on clinical supervision of mental health nursing staff. The intervention was designed to strengthen already existing supervision practices through...... educational preparation for supervision and systematic reflection on supervision. The intervention consists of three sessions and was implemented on two groups of mental health hospital staff. We present an outline of the manual and explain how the trial sessions made us adjust the preliminary manual....... The effects of implementing the manual will subsequently be analysed in an independent randomised controlled trial....

  7. Detecting altered postural control after cerebral concussion in athletes with normal postural stability

    OpenAIRE

    Cavanaugh, J; Guskiewicz, K; Giuliani, C; Marshall, S; Mercer, V; Stergiou, N

    2005-01-01

    Objective: To determine if approximate entropy (ApEn), a regularity statistic from non-linear dynamics, could detect changes in postural control during quiet standing in athletes with normal postural stability after cerebral concussion.

  8. Co-simulation of heavy truck tire dynamics and electronic stability control systems (phase B).

    Science.gov (United States)

    2010-07-01

    In the past decade, electronic stability controls (ESC) have become increasingly common on vehicles operating in the United States. The acceptance of this technology has progressed to the point where all new passenger vehicles sold in the US are requ...

  9. Stabilization of an Underactuated Surface Vessel Based on Adaptive Sliding Mode and Backstepping Control

    Directory of Open Access Journals (Sweden)

    Fuguang Ding

    2013-01-01

    Full Text Available The paper studied controlling problem of an underactuated surface vessel with unknown interferences. It proved that the control problem of underactuated surface vessel can be transformed into the stabilization analysis of two small subsystems. This controller was designed by backstepping method and adaptive sliding mode, was suitable for solving the problem of the control of higher systems, can keep the system global asymptotic stability, and can inhibit unknown interference, and boundary layer can weaken the buffeting generated by sliding mode. The unknown interference was estimated by adaptive function. Finally, the simulation results are given to demonstrate the effectiveness of the proposed control laws.

  10. DESCRIBING FUNCTION METHOD FOR PI-FUZZY CONTROLLED SYSTEMS STABILITY ANALYSIS

    Directory of Open Access Journals (Sweden)

    Stefan PREITL

    2004-12-01

    Full Text Available The paper proposes a global stability analysis method dedicated to fuzzy control systems containing Mamdani PI-fuzzy controllers with output integration to control SISO linear / linearized plants. The method is expressed in terms of relatively simple steps, and it is based on: the generalization of the describing function method for the considered fuzzy control systems to the MIMO case, the approximation of the describing functions by applying the least squares method. The method is applied to the stability analysis of a class of PI-fuzzy controlled servo-systems, and validated by considering a case study.

  11. Robust Stabilization of Fractional-Order Systems with Interval Uncertainties via Fractional-Order Controllers

    Directory of Open Access Journals (Sweden)

    Mohammadtaghi Hamidi Beheshti

    2010-01-01

    Full Text Available We propose a fractional-order controller to stabilize unstable fractional-order open-loop systems with interval uncertainty whereas one does not need to change the poles of the closed-loop system in the proposed method. For this, we will use the robust stability theory of Fractional-Order Linear Time Invariant (FO-LTI systems. To determine the control parameters, one needs only a little knowledge about the plant and therefore, the proposed controller is a suitable choice in the control of interval nonlinear systems and especially in fractional-order chaotic systems. Finally numerical simulations are presented to show the effectiveness of the proposed controller.

  12. Stabilization of prescribed values and periodic orbits with regular and pulse target oriented control

    International Nuclear Information System (INIS)

    Braverman, E.; Chan, B.

    2014-01-01

    Investigating a method of chaos control for one-dimensional maps, where the intervention is proportional to the difference between a fixed value and a current state, we demonstrate that stabilization is possible in one of the two following cases: (1) for small values, the map is increasing and the slope of the line connecting the points on the line with the origin is decreasing; (2) the chaotic map is locally Lipschitz. Moreover, in the latter case we prove that any point of the map can be stabilized. In addition, we study pulse stabilization when the intervention occurs each m-th step and illustrate that stabilization is possible for the first type of maps. In the context of population dynamics, we notice that control with a positive target, even if stabilization is not achieved, leads to persistent solutions and prevents extinction in models which experience the Allee effect

  13. Controllability and Stabilization of Bilinear and Semilinear Partial Differential Equations

    DEFF Research Database (Denmark)

    Krishnaswamy, Vijayaraghavan

    The topic of the thesis is the investigation of the question of controllability of weakly nonlinear partial differntial equations. The method is based on the Hilbert Uniqueness Method.......The topic of the thesis is the investigation of the question of controllability of weakly nonlinear partial differntial equations. The method is based on the Hilbert Uniqueness Method....

  14. The Stability Analysis and New Torque Control Strategy of Direct-Driven PMSG Wind Turbines

    OpenAIRE

    Jun Liu; Feihang Zhou; Gungyi Wang

    2016-01-01

    This paper expounds on the direct-driven PMSG wind power system control strategy, and analyses the stability conditions of the system. The direct-driven PMSG wind power system may generate the intense mechanical vibration, when wind speed changes dramatically. This paper proposes a new type of torque control strategy, which increases the system damping effectively, mitigates mechanical vibration of the system, and enhances the stability conditions of the system. The simulation results verify ...

  15. ANALYSIS OF PERTURBED MOTION STABILITY OF WHEELER VEHICLES BRAKES CONTROL SYSTEM

    Directory of Open Access Journals (Sweden)

    V. Verbytskiyi

    2011-01-01

    Full Text Available The analysis of the perturbed motion stability of the brake automatic control system on the basis of Lyapunov’s second method is carried out. Using transformations of Lurie there has been ob-tained the canonical form of the system of equations of automatic control. It allowed determining the necessary and sufficient conditions of the asymptotic stability of the system irrespective of its initial condition and a definite choice of the admissible characteristic of the regulator.

  16. The Effect of Financial Management Knowledge, Competence and Supervision Act of the Government’s Internal Control Officer on the Quality of Government’s Performance Accountability Report Evaluation

    Directory of Open Access Journals (Sweden)

    Mulia Saputra

    2016-06-01

    Full Text Available This study aims to determine effect of financial management knowledge, competence and supervision of the internal control official act of government (either simultaneously or partially on the quality evaluation of performance accountability reports of government agencies (BPKP Representative Studies in Aceh Province. This study is hypothesis testing research by testing using multiple linear regressions of the data collected through questionnaires. This population is 71 auditors Government Internal Supervisory Apparatus (APIP on BPKP Representative in Aceh province. Data analysis was performed using SPSS (Statistical Package for Social Science. The results showed that the financial management knowledge, competence and supervision of the actions of Government Internal Supervisory Apparatus take effect simultaneously and partially on the quality of evaluations Accountability Report Government Performance.

  17. Effects of supervised structured aerobic exercise training program on fasting blood glucose level, plasma insulin level, glycemic control, and insulin resistance in type 2 diabetes mellitus.

    Science.gov (United States)

    Shakil-Ur-Rehman, Syed; Karimi, Hossein; Gillani, Syed Amir

    2017-01-01

    To determine the effects of supervised structured aerobic exercise training (SSAET) program on fasting blood glucose level (FBGL), plasma insulin level (PIL), glycemic control (GC), and insulin resistance (IR) in type 2 diabetes mellitus (T2DM). Riphah Rehabilitation and Research Centre (RRRC) was the clinical setting for this randomized controlled trial, located at Pakistan Railways General Hospital (PRGH), Rawalpindi, Pakistan. Study duration was 18 months from January 1, 2015 to June 30, 2016. Patients of both genders ranging 40-70 years of age with at least one year of history of T2DM were considered eligible according to WHO criteria, while patients with other chronic diseases, history of smoking, regular exercise and diet plan were excluded. Cohorts of 195 patients were screened out of whom 120 fulfilled the inclusion criteria. Amongst them 102 agreed to participate and were assigned to experimental (n=51) and control (n=51) groups. Experimental group underwent SSAET program, routine medication and dietary plan, whereas the control group received routine medication and dietary plan, while both group received treatment for 25 weeks. The blood samples were taken at baseline and on the completion of 25 weeks. The investigation of fasting blood glucose level, plasma insulin level, and glycemic control was conducted to calculate IR. Patients with T2DM in experimental group (n=51) treated with SSAET program, routine medication and dietary plan significantly improved FBGL (pre-mean= 276.41±25.31, post-mean=250.07±28.23), PIL (pre-mean=13.66±5.31, post-mean=8.91±3.83), GC (pre-mean=8.31±1.79, post-mean 7.28±1.43), and IR (pre-mean=64.95±27.26, post-mean 37.97±15.58), as compared with patients in control group treated with routine medication and dietary plan in whom deteriorations were noted in FBGL (pre-mean=268.19±22.48, post-mean=281.41±31.30), PIL(pre-mean=14.14±5.48, post-mean=14.85±5.27) GC (pre-mean=8.15±1.74, post-mean=8.20±1.44, and IR (pre

  18. Comparison of model reference and map based control method for vehicle stability enhancement

    NARCIS (Netherlands)

    Baek, S.; Son, M.; Song, J.; Boo, K.; Kim, H.

    2012-01-01

    A map based controller method to improve a vehicle lateral stability is proposed in this study and compared with the conventional method, a model referenced controller. A model referenced controller to determine compensated yaw moment uses the sliding mode method, but the proposed map based

  19. Improving Banking Supervision

    OpenAIRE

    Mayes, David G.

    1998-01-01

    This paper explains how banking supervision within the EU, and in Finland in particular, can be improved by the implementation of greater market discipline and related changes. Although existing EU law, institutions, market structures and practices of corporate governance restrict the scope for change, substantial improvements can be introduced now while there is a window of opportunity for change. The economy is growing H5ly and the consequences of the banking crises of the early 1990s have ...

  20. A Combination of PD Controller and PIAFC for Stabilization of “x” Configuration Quadcopter

    Directory of Open Access Journals (Sweden)

    Ni’am Tamami

    2014-06-01

    Full Text Available This paper presents a stabilization control method for “x” configuration quadcopter. The control method used the combination of PD (Proportional Derivative controller and PIAFC (Proportional Integral Active Force Control. PD is used to stabilize quadcopter, and PIAFC is used to reject uncertainty disturbance (e.g. wind by estimating disturbance torque value of quadcopter. The PD with PIAFC provided better result where PIAFC could minimize uncertain disturbance effect. The simulation has successfully give comparation about controller performance (PD, PD-AFC, PD-PIAFC by calculate RMS (Root Mean Square value. PD with AFC gives better result than PD. AFC optimization using PI (PD-PIAFC give best result if compared with PD or PD-AFC. PD-PIAFC has lowest RMS value of result control signal, 0.0389 for constant disturbance and 0.1008 for fluctuated disturbance. Keywords:“x” configuration quadcopter, stability, PD, PIAFC.

  1. Robust stabilization control based on guardian maps theory for a longitudinal model of hypersonic vehicle.

    Science.gov (United States)

    Liu, Yanbin; Liu, Mengying; Sun, Peihua

    2014-01-01

    A typical model of hypersonic vehicle has the complicated dynamics such as the unstable states, the nonminimum phases, and the strong coupling input-output relations. As a result, designing a robust stabilization controller is essential to implement the anticipated tasks. This paper presents a robust stabilization controller based on the guardian maps theory for hypersonic vehicle. First, the guardian maps theories are provided to explain the constraint relations between the open subsets of complex plane and the eigenvalues of the state matrix of closed-loop control system. Then, a general control structure in relation to the guardian maps theories is proposed to achieve the respected design demands. Furthermore, the robust stabilization control law depending on the given general control structure is designed for the longitudinal model of hypersonic vehicle. Finally, a simulation example is provided to verify the effectiveness of the proposed methods.

  2. Assessing control of postural stability in community-living older adults using performance-based limits of stability

    Directory of Open Access Journals (Sweden)

    Boissy Patrick

    2008-03-01

    Full Text Available Abstract Background Balance disability measurements routinely used to identify fall risks in frail populations have limited value in the early detection of postural stability deficits in community-living older adults. The objectives of the study were to 1 measure performance-based limits of stability (LOS in community-living older adults and compare them to theoretical LOS computed from data proposed by the Balance Master® system, 2 explore the feasibility of a new measurement approach based on the assessment of postural stability during weight-shifting tasks at performance-based LOS, 3 quantify intra-session performance variability during multiple trials using the performance-based LOS paradigm. Methods Twenty-four healthy community-living older adults (10 men, 14 women aged between 62 to 85 (mean age ± sd, 71.5 ± 6 yrs participated in the study. Subjects' performance-based LOS were established by asking them to transfer their body weight as far as possible in three directions (forward, right and left without changing their base of support. LOS were computed as the maximal excursion of the COP in each direction among three trials. Participants then performed two experimental tasks that consisted in controlling, with the assistance of visual feedback, their centre of pressure (COP within two predefined targets set at 100% of their performance-based LOS. For each tasks 8 trials were performed. Ground reaction forces and torques during performance-based LOS evaluation and experimental tasks were recorded with a force plate. Sway area and medio-lateral mean COP displacement speed variables were extracted from force plate recordings. Results Significant differences between theoretical LOS computed from maximum leaning angles derived from anthropometric characteristics and performance-based LOS were observed. Results showed that a motor learning effect was present as the participants optimized their weight-shifting strategy through the first three

  3. Stabilization and Control Models of Systems With Hysteresis Nonlinearities

    Directory of Open Access Journals (Sweden)

    Mihail E. Semenov

    2012-05-01

    Full Text Available Mechanical and economic systems with hysteresis nonlinearities are studied in article. Dissipativity condition of inverted pendulum under the hysteresis control is obtained. The solution of the optimal production strategy problem was found where price has hysteresis behaviour.

  4. Controller synthesis for string stability of vehicle platoons

    NARCIS (Netherlands)

    Ploeg, J.; Shukla, D.P.; Wouw, N. van de; Nijmeijer, H.

    2014-01-01

    Cooperative adaptive cruise control (CACC) allows for short-distance automatic vehicle following using intervehicle wireless communication in addition to onboard sensors, thereby potentially improving road throughput. In order to fulfill performance, safety, and comfort requirements, a CACC-equipped

  5. Ethics in education supervision

    Directory of Open Access Journals (Sweden)

    Fatma ÖZMEN

    2008-06-01

    Full Text Available Supervision in education plays a crucial role in attaining educational goals. In addition to determining the present situation, it has a theoretical and practical function regarding the actions to be taken in general and the achievement of teacher development in particular to meet the educational goals in the most effective way. For the education supervisors to act ethically in their tasks while achieving this vital mission shall facilitate them to build up trust, to enhance the level of collaboration and sharing, thus it shall contribute to organizational effectiveness. Ethics is an essential component of educational supervision. Yet, it demonstrates rather vague quality due to the conditions, persons, and situations. Therefore, it is a difficult process to develop the ethical standards in institutions. This study aims to clarify the concept of ethics, to bring up its importance, and to make recommendations for more effective supervisions from the aspect of ethics, based on the literature review, some research results, and sample cases reported by teachers and supervisors.

  6. Self-Supervised Dynamical Systems

    Science.gov (United States)

    Zak, Michail

    2003-01-01

    metal aspects of a monad is implemented by feedback from mental to motor dynamics, as represented by the aforementioned fictitious forces. This feedback is what makes the evolution of probability densities nonlinear. The deviation from linear evolution can be characterized, in a sense, as an expression of free will. It has been demonstrated that probability densities can approach prescribed attractors while exhibiting such patterns as shock waves, solitons, and chaos in probability space. The concept of self-supervised dynamical systems has been considered for application to diverse phenomena, including information-based neural networks, cooperation, competition, deception, games, and control of chaos. In addition, a formal similarity between the mathematical structures of self-supervised dynamical systems and of quantum-mechanical systems has been investigated.

  7. Large Signal Stabilization of Hybrid AC/DC Micro-Grids Using Nonlinear Robust Controller

    Directory of Open Access Journals (Sweden)

    Reza Pejmanfar

    2017-12-01

    Full Text Available This paper presents a robust nonlinear integrated controller to improve stability of hybrid AC/DC micro-grids under islanding mode. The proposed controller includes two independent controllers where each one is responsible to control one part of the system. First controller will improve the stability of input DC/DC converter. Using this controller, the voltage of DC bus is fully stabilized such that when a large disturbance occurs, its voltage will become constant without any significant dynamic. The necessity of DC bus regulation which has not been considered in previous studies, is imminent as it not only improves voltage stability of the micro-grid but also protects consumers which are directly connected to the DC bus, against voltage variations. Frequency stability of the micro-grid is provided by the second proposed controller which is applied to output DC/AC converter of the micro-grid. Adaptive method is used to make the controllers proposed in this paper, robust. Duty cycle of converters switches are adjusted such that voltage and frequency of the micro-grid are set on the desired value in minimum possible time under transient disturbances and uncertainty of the loads as well as micro-sources characteristics.

  8. Group supervision for general practitioners

    DEFF Research Database (Denmark)

    Galina Nielsen, Helena; Sofie Davidsen, Annette; Dalsted, Rikke

    2013-01-01

    AIM: Group supervision is a sparsely researched method for professional development in general practice. The aim of this study was to explore general practitioners' (GPs') experiences of the benefits of group supervision for improving the treatment of mental disorders. METHODS: One long-establish......AIM: Group supervision is a sparsely researched method for professional development in general practice. The aim of this study was to explore general practitioners' (GPs') experiences of the benefits of group supervision for improving the treatment of mental disorders. METHODS: One long...... considered important prerequisites for disclosing and discussing professional problems. CONCLUSION: The results of this study indicate that participation in a supervision group can be beneficial for maintaining and developing GPs' skills in dealing with patients with mental health problems. Group supervision...... influenced other areas of GPs' professional lives as well. However, more studies are needed to assess the impact of supervision groups....

  9. Virtual Inertia Control-Based Model Predictive Control for Microgrid Frequency Stabilization Considering High Renewable Energy Integration

    Directory of Open Access Journals (Sweden)

    Thongchart Kerdphol

    2017-05-01

    Full Text Available Renewable energy sources (RESs, such as wind and solar generations, equip inverters to connect to the microgrids. These inverters do not have any rotating mass, thus lowering the overall system inertia. This low system inertia issue could affect the microgrid stability and resiliency in the situation of uncertainties. Today’s microgrids will become unstable if the capacity of RESs become larger and larger, leading to the weakening of microgrid stability and resilience. This paper addresses a new concept of a microgrid control incorporating a virtual inertia system based on the model predictive control (MPC to emulate virtual inertia into the microgrid control loop, thus stabilizing microgrid frequency during high penetration of RESs. The additional controller of virtual inertia is applied to the microgrid, employing MPC with virtual inertia response. System modeling and simulations are carried out using MATLAB/Simulink® software. The simulation results confirm the superior robustness and frequency stabilization effect of the proposed MPC-based virtual inertia control in comparison to the fuzzy logic system and conventional virtual inertia control in a system with high integration of RESs. The proposed MPC-based virtual inertia control is able to improve the robustness and frequency stabilization of the microgrid effectively.

  10. 19 CFR 19.38 - Supervision of exportation.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Supervision of exportation. 19.38 Section 19.38 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY CUSTOMS WAREHOUSES, CONTAINER STATIONS AND CONTROL OF MERCHANDISE THEREIN Duty-Free Stores § 19.38 Supervision of exportation. (a) Sales...

  11. Feedback-controlled NTM stabilization on ASDEX Upgrade

    Directory of Open Access Journals (Sweden)

    Stober J.

    2015-01-01

    Full Text Available On ASDEX Upgrade a concept for real-time stabilization of NTMs has been realized and successfully applied to (3,2- and (2,1-NTMs. Since most of the work has meanwhile been published elsewhere, a short summary with the appropriate references is given. Limitations, deficits and future extensions of the system are discussed. In a second part the recent work on using modulated ECCD for NTM stabilisation is described in some detail. In these experiments ECCD power is modulated according to a magnetic footprint of the rotating NTM. In agreement with earlier results it could be shown that O-point heating reduces the necessary average power for stabilisation whereas X-point heating hampers stabilisation. Although this modulated scheme is not relevant for routine NTM stabilisation on ASDEX Upgrade it may be mandatory for ITER or DEMO. On ASDEX Upgrade it has been re-developed to demonstrate the usage of a FAst DIrectional Switch to continously heat the O-point of the rotating island with only one gyrotron switching between two launchers which target the mode at locations separated in phase by 180 degrees as described in [1].

  12. Robust D-Stability Controller Design for a Ducted Fan Unmanned Aerial Vehicle

    Directory of Open Access Journals (Sweden)

    Xiao-lu Ren

    2014-01-01

    Full Text Available This paper deals with the aerodynamic modeling of a small ducted fan UAV and the problem of attitude stabilization when the parameter of the vehicle is varied. The main aerodynamic model of the hovering flight UAV is first presented. Then, an attitude control is designed from a linearization of the dynamic model around the hovering flight, which is based on the H∞ output feedback control theory with D-stability. Simulation results show that such method has good robustness to the attitude system. They can meet the requirements of attitude control and verify further the feasibility of such a control strategy.

  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. Stability and control of wind farms in power systems

    DEFF Research Database (Denmark)

    Jauch, Clemens

    is part of the project. The mostextensive modelling work deals with the design of the electrical part of the variable speed turbine and its controls. To simulate realistic grid operation the wind turbine models are connected to an aggregated model of the Nordic power system. For thatpurpose the Nordic...... through transient faults. With these transient fault controllers the wind turbines can stay connected to the grid, such that their generation capacity is sustained, and normal gridoperation can resume, after the fault is cleared. Transient faults in the transmission system often cause power system...... oscillations. To further support the grid, a situation is assumed, where in future, wind turbines will be required to contribute to thedamping of these power system oscillations. Power system oscillations are counteracted with a controlled injection of oscillating active power. With an active-stall turbine...

  15. Energy efficient refrigeration. Efficient control, supervision and system solutions. Project 1. Final report; Energieffektivare kyla - effektivare styrning, oevervakning och systemloesningar. Etapp 1. Slutrapport

    Energy Technology Data Exchange (ETDEWEB)

    Claesson, Joachim [Royal Inst. of Technology, Stockholm (Sweden). Dept. of Energy Technology

    2006-01-15

    The present report collects and summarizes phase 1 of the project Efficient Supermarket Refrigeration - Project 1: Efficient Control, Supervision, and System solutions. At the very beginning of the project a survey were carried out, in order to establish the current state of supermarket refrigeration, the industry representatives view of a typical Swedish supermarket, and what problems they felt important to solve. Mainly two specific points emerged; Defrost issues and Optimization of Refrigerant system and its component, either remotely and/or automatically. The typical Swedish supermarket solution obtained from the survey was then used in order to design and construct an experimental 'supermarket' mockup. This experimental facility was built in the laboratory of IUC in Katrineholm, Sweden. The test facility was constructed as to deviate as little as possible from a real installation in a supermarket. Some extra features were added in order to being able to evaluate different solutions on the the key issues identified in the survey. Available literature concerning defrost, methods for defrost, and the impact of climate on the defrost cycle; have been collected and reported in a separate report. The major part of that report is included also in the present report. It may be concluded that the climate has a significant impact on the energy consumption of the refrigeration system and defrost demand. It is shown in the literature that it is a good idea to decrease the water content of the air in the supermarket, using the air supply unit, rather than having the cabinets drying the air. It may be recommended to decrease the relative humidity in the store to the lowest allowable. The need for demand initiated defrost sequence is apparent in the literature, but no single acceptable technique have been identified. In addition, demand terminating defrost sequence is an important issue to resolve. In the literature survey, several defrost alternative is described

  16. Nonlinear Slewing Spacecraft Control Based on Exergy, Power Flow, and Static and Dynamic Stability

    Science.gov (United States)

    Robinett, Rush D.; Wilson, David G.

    2009-10-01

    This paper presents a new nonlinear control methodology for slewing spacecraft, which provides both necessary and sufficient conditions for stability by identifying the stability boundaries, rigid body modes, and limit cycles. Conservative Hamiltonian system concepts, which are equivalent to static stability of airplanes, are used to find and deal with the static stability boundaries: rigid body modes. The application of exergy and entropy thermodynamic concepts to the work-rate principle provides a natural partitioning through the second law of thermodynamics of power flows into exergy generator, dissipator, and storage for Hamiltonian systems that is employed to find the dynamic stability boundaries: limit cycles. This partitioning process enables the control system designer to directly evaluate and enhance the stability and performance of the system by balancing the power flowing into versus the power dissipated within the system subject to the Hamiltonian surface (power storage). Relationships are developed between exergy, power flow, static and dynamic stability, and Lyapunov analysis. The methodology is demonstrated with two illustrative examples: (1) a nonlinear oscillator with sinusoidal damping and (2) a multi-input-multi-output three-axis slewing spacecraft that employs proportional-integral-derivative tracking control with numerical simulation results.

  17. Single Stance Stability and Proprioceptive Control in Older Adults Living at Home: Gender and Age Differences

    Directory of Open Access Journals (Sweden)

    Dario Riva

    2013-01-01

    Full Text Available In developed countries, falls in older people represent a rising problem. As effective prevention should start before the risk becomes evident, an early predictor is needed. Single stance instability would appear as a major risk factor. Aims of the study were to describe single stance stability, its sensory components, and their correlation with age and gender. A random sample of 597 older adults (319 men, 278 women living at home, aged 65–84, was studied. Stability tests were performed with an electronic postural station. The single stance test showed the impairment of single stance stability in older individuals (75–84 yrs. The significant decline of stability in the older subjects may be explained by the impairment of proprioceptive control together with the decrease in compensatory visual stabilization and emergency responses. Younger subjects (65–74 yrs exhibited better, but still inadequate, proprioceptive control with compensatory visual stabilization. Gender differences appeared in older subjects: women were significantly less stable than men. The measurement of the sensory components of single stance stability could aid in the early detection of a decay in antigravity movements many years before the risk of falling becomes evident. Adequate proprioceptive control could mitigate the effects of all other risks of falling.

  18. Single Stance Stability and Proprioceptive Control in Older Adults Living at Home: Gender and Age Differences

    Science.gov (United States)

    Riva, Dario; Mamo, Carlo; Fanì, Mara; Saccavino, Patrizia; Rocca, Flavio; Momenté, Manuel; Fratta, Marianna

    2013-01-01

    In developed countries, falls in older people represent a rising problem. As effective prevention should start before the risk becomes evident, an early predictor is needed. Single stance instability would appear as a major risk factor. Aims of the study were to describe single stance stability, its sensory components, and their correlation with age and gender. A random sample of 597 older adults (319 men, 278 women) living at home, aged 65–84, was studied. Stability tests were performed with an electronic postural station. The single stance test showed the impairment of single stance stability in older individuals (75–84 yrs). The significant decline of stability in the older subjects may be explained by the impairment of proprioceptive control together with the decrease in compensatory visual stabilization and emergency responses. Younger subjects (65–74 yrs) exhibited better, but still inadequate, proprioceptive control with compensatory visual stabilization. Gender differences appeared in older subjects: women were significantly less stable than men. The measurement of the sensory components of single stance stability could aid in the early detection of a decay in antigravity movements many years before the risk of falling becomes evident. Adequate proprioceptive control could mitigate the effects of all other risks of falling. PMID:23984068

  19. Analysis and improvement of digital control stability for master-slave manipulator system

    International Nuclear Information System (INIS)

    Yoshida, Koichi; Yabuta, Tetsuro

    1992-01-01

    Some bilateral controls of master-slave system have been designed, which can realize high-fidelity telemanipulation as if the operator were manipulating the object directly. While usual robot systems are controlled by software-servo system using digital computer, little work has been published on design and analysis for digital control of these systems, which must consider time-delay of sensor signals and zero order hold effect of command signals on actuators. This paper presents a digital control analysis for single degree of freedom master-slave system including impedance models of both the human operator and the task object, which clarifies some index for the stability. The stability result shows a virtual master-slave system concepts, which improve the digital control stability. We first analyze a dynamic control method of master-slave system in discrete-time system for the stability problem, which can realize high-fidelity telemanipulation in the continuous-time. Secondly, using the results of the stability analysis, the robust control scheme for master-slave system is proposed, and the validity of this scheme is finally confirmed by the simulation. Consequently, it would be considered that any combination of master and slave modules with dynamic model of these manipulators is possible to construct the stable master-slave system. (author)

  20. Fault Tolerant Emergency Control to Preserve Power System Stability

    DEFF Research Database (Denmark)

    Pedersen, Andreas Søndergaard; Richter, Jan H.; Tabatabaeipour, Mojtaba

    2016-01-01

    This paper introduces a method for fault-masking and system reconfiguration in power transmission systems. The paper demonstrates how faults are handled by reconfiguring remaining controls through utilisation of wide-area measurement in real time. It is shown how reconfiguration can be obtained u...

  1. Maintaining genetic stability in a control flock of South African ...

    African Journals Online (AJOL)

    means of whole progeny and replacement groups for the measured characters ... The whole problem of the estimation of genetic change was ... that a genetic control flock is a segregating population in which ... 5,5 years, were divided into five equal groups by stratified ..... A note on tests of significance and optimal ex-.

  2. A cluster randomised controlled trial of a manualised cognitive behavioural anger management intervention delivered by supervised lay therapists to people with intellectual disabilities.

    Science.gov (United States)

    Willner, P; Rose, J; Jahoda, A; Stenfert Kroese, B; Felce, D; MacMahon, P; Stimpson, A; Rose, N; Gillespie, D; Shead, J; Lammie, C; Woodgate, C; Townson, J K; Nuttall, J; Cohen, D; Hood, K

    2013-05-01

    Anger is a frequent problem for many people with intellectual disabilities, and is often expressed as verbal and/or physical aggression. Cognitive-behaviour therapy (CBT) is the treatment of choice for common mental health problems, but CBT has only recently been adapted for people with intellectual disabilities. Anger is the main psychological presentation in which controlled trials have been used to evaluate CBT interventions for people with intellectual disabilities but these do not include rigorous randomised studies. To evaluate (1) the impact of a staff-delivered manualised CBT anger management intervention on (a) reported anger among people with mild to moderate intellectual disabilities, and (b) anger coping skills, aggression, mental health, quality of life and costs of health and social care; (2) factors that influence outcome; and (3) the experience of service users, lay therapists and service managers. A cluster randomised controlled trial based on 30 day centres (15 intervention and 15 control). Intention-to-treat comparisons of outcomes used a two-level linear regression model to allow for clustering within centres with baseline outcome levels as a covariate. Comparison of cost data used non-parametric bootstrapping. Qualitative analysis used interpretative phenomenological analysis and thematic analysis. Recruited day centres had four-plus service users with problem anger who were prepared to participate, two-plus staff willing to be lay therapists, a supportive manager and facilities for group work, and no current anger interventions. A total of 212 service users with problem anger were recruited. Thirty-three were deemed ineligible (30 could not complete assessments and three withdrew before randomisation). Retention at follow-up was 81%, with 17 withdrawals in each arm. Two to four staff per centre were recruited as lay therapists. Eleven service users, nine lay therapists and eight managers were interviewed. The manualised intervention comprised

  3. Control Path of Pesticide Residual Under the System of Agricultural Products Supervision:A Case Study of A Village in Zhejiang Province, China

    Directory of Open Access Journals (Sweden)

    HUANG Wen-fang

    2014-02-01

    Full Text Available There is relation between the pesticide application and quality of agricultural products. The paper explored the causes and ways to deal with it from the view of agricultural development on the case study of pesticide management and use in a village, Zhejiang Province on the basis of investigation of local government, agriculture technology service station and farmers. The paper pointed out that lack of supervi-sion in the pesticide use and result was only external; the true reasons were high supervise cost and limited service of agriculture technology service station. So the paper drew the conclusions that multifunction agriculture development, superior agriculture produce service system and the change of village committee's role and responsibility were the best answers to the agricultural products safety problem.

  4. Microcrystalline silicon deposition: Process stability and process control

    International Nuclear Information System (INIS)

    Donker, M.N. van den; Kilper, T.; Grunsky, D.; Rech, B.; Houben, L.; Kessels, W.M.M.; Sanden, M.C.M. van de

    2007-01-01

    Applying in situ process diagnostics, we identified several process drifts occurring in the parallel plate plasma deposition of microcrystalline silicon (μc-Si:H). These process drifts are powder formation (visible from diminishing dc-bias and changing spatial emission profile on a time scale of 10 0 s), transient SiH 4 depletion (visible from a decreasing SiH emission intensity on a time scale of 10 2 s), plasma heating (visible from an increasing substrate temperature on a time scale of 10 3 s) and a still puzzling long-term drift (visible from a decreasing SiH emission intensity on a time scale of 10 4 s). The effect of these drifts on the crystalline volume fraction in the deposited films is investigated by selected area electron diffraction and depth-profiled Raman spectroscopy. An example shows how the transient depletion and long-term drift can be prevented by suitable process control. Solar cells deposited using this process control show enhanced performance. Options for process control of plasma heating and powder formation are discussed

  5. Resistance to group clinical supervision

    DEFF Research Database (Denmark)

    Buus, Niels; Delgado, Cynthia; Traynor, Michael

    2018-01-01

    This present study is a report of an interview study exploring personal views on participating in group clinical supervision among mental health nursing staff members who do not participate in supervision. There is a paucity of empirical research on resistance to supervision, which has traditiona......This present study is a report of an interview study exploring personal views on participating in group clinical supervision among mental health nursing staff members who do not participate in supervision. There is a paucity of empirical research on resistance to supervision, which has...... traditionally been theorized as a supervisee's maladaptive coping with anxiety in the supervision process. The aim of the present study was to examine resistance to group clinical supervision by interviewing nurses who did not participate in supervision. In 2015, we conducted semistructured interviews with 24...... Danish mental health nursing staff members who had been observed not to participate in supervision in two periods of 3 months. Interviews were audio-recorded and subjected to discourse analysis. We constructed two discursive positions taken by the informants: (i) 'forced non-participation', where...

  6. Control and Stabilization of the Benjamin-Ono Equation in {L^2({{T})}}

    Science.gov (United States)

    Laurent, Camille; Linares, Felipe; Rosier, Lionel

    2015-12-01

    We study the control and stabilization of the Benjamin-Ono equation in {L^2({T})}, the lowest regularity where the initial value problem is well-posed. This problem was already initiated in Linares and Rosier (Trans Am Math Soc 367:4595-4626, 2015) where a stronger stabilization term was used (that makes the equation of parabolic type in the control zone). Here we employ a more natural stabilization term related to the L 2-norm. Moreover, by proving a theorem of controllability in L 2, we manage to prove the global controllability in large time. Our analysis relies strongly on the bilinear estimates proved in Molinet and Pilod (Anal PDE 5:365-395, 2012) and some new extension of these estimates established here.

  7. Decentralized Feedback Controllers for Exponential Stabilization of Hybrid Periodic Orbits: Application to Robotic Walking*

    Science.gov (United States)

    Hamed, Kaveh Akbari; Gregg, Robert D.

    2016-01-01

    This paper presents a systematic algorithm to design time-invariant decentralized feedback controllers to exponentially stabilize periodic orbits for a class of hybrid dynamical systems arising from bipedal walking. The algorithm assumes a class of parameterized and nonlinear decentralized feedback controllers which coordinate lower-dimensional hybrid subsystems based on a common phasing variable. The exponential stabilization problem is translated into an iterative sequence of optimization problems involving bilinear and linear matrix inequalities, which can be easily solved with available software packages. A set of sufficient conditions for the convergence of the iterative algorithm to a stabilizing decentralized feedback control solution is presented. The power of the algorithm is demonstrated by designing a set of local nonlinear controllers that cooperatively produce stable walking for a 3D autonomous biped with 9 degrees of freedom, 3 degrees of underactuation, and a decentralization scheme motivated by amputee locomotion with a transpelvic prosthetic leg. PMID:27990059

  8. Pseudodifferential Perturbations and Stabilization of Distributed Parameter Systems: Dirichlet Feedback Control Problems

    DEFF Research Database (Denmark)

    Pedersen, Michael

    1991-01-01

    The stabilization problems for parabolic and hyperbolic partial differential equations with Dirichlet boundary condition are considered. The systems are stabilized by a boundary feedback in(1) The operator equation,(2) The boundary condition,(3) Both the operator equation and the boundary condition...... turns out to be a shortcut to some of the stabilization results of Lasiecka and Triggiani in [J. Differential Equations, 47 (1983), pp. 245-272], [SIAM J. Control Optim., 21(1983), pp. 766-802], and [Appl. Math. Optim., 8(1981), pp. 1-37], and it illuminates to some extent how a change of boundary...

  9. Stability test and analysis of the Space Shuttle Primary Reaction Control Subsystem thruster

    Science.gov (United States)

    Applewhite, John; Hurlbert, Eric; Krohn, Douglas; Arndt, Scott; Clark, Robert

    1992-01-01

    The results are reported of a test program conducted on the Space Shuttle Primary Reaction Control Subsystem thruster in order to investigate the effects of trapped helium bubbles and saturated propellants on stability, determine if thruster-to-thruster stability variations are significant, and determine stability under STS-representative conditions. It is concluded that the thruster design is highly reliable in flight and that burn-through has not occurred. Significantly unstable thrusters are screened out, and wire wrap is found to protect against chamber burn-throughs and to provide a fail-safe thruster for this situation.

  10. Stabilizing model predictive control of a gantry crane based on flexible set-membership constraints

    NARCIS (Netherlands)

    Iles, Sandor; Lazar, M.; Kolonic, Fetah; Jadranko, Matusko

    2015-01-01

    This paper presents a stabilizing distributed model predictive control of a gantry crane taking into account the variation of cable length. The proposed algorithm is based on the off-line computation of a sequence of 1-step controllable sets and a condition that enables flexible convergence towards

  11. Proportional derivative based stabilizing control of paralleled grid converters with cables in renewable power plants

    DEFF Research Database (Denmark)

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

    2014-01-01

    consisting in LCL filters and cables. Both grid and converter current controls are analyzed. The frequency region, within which the system may be destabilized, is identified by means of the impedance-based stability analysis and frequency-domain passivity theory. A proportional derivative control strategy...

  12. Robust Stability Clearance of Flight Control Law Based on Global Sensitivity Analysis

    OpenAIRE

    Ou, Liuli; Liu, Lei; Dong, Shuai; Wang, Yongji

    2014-01-01

    To validate the robust stability of the flight control system of hypersonic flight vehicle, which suffers from a large number of parametrical uncertainties, a new clearance framework based on structural singular value ( $\\mu $ ) theory and global uncertainty sensitivity analysis (SA) is proposed. In this framework, SA serves as the preprocess of uncertain model to be analysed to help engineers to determine which uncertainties affect the stability of the closed loop system more slightly. By ig...

  13. Quality control and stability study of 100 mg/ml paracetamol oral drops

    International Nuclear Information System (INIS)

    Garcia Penna, Caridad M.; Montes de Oca Porto, Yanet; Salomon Izquierdo, Suslebys

    2013-01-01

    Paracetamol is an effective analgesic and antipyretic drug of the non-steroidal anti-inflammatory drug group. Paracetamol oral drops are indicated for use in infant population aged up to 5 years to relieve fever, headache, toothache and symptomatic relief of common cold. To validate two analytical methods for the quality control and the stability study and to study the stability of 100 mg/ml Paracetamol oral drops made in Cuba

  14. Electronic differential control of 2WD electric vehicle considering steering stability

    Science.gov (United States)

    Hua, Yiding; Jiang, Haobin; Geng, Guoqing

    2017-03-01

    Aiming at the steering wheel differential steering control technology of rear wheel independent driving electric wheel, considering the assisting effect of electronic differential control on vehicle steering, based on the high speed steering characteristic of electric wheel car, the electronic differential speed of auxiliary wheel steering is also studied. A yaw moment control strategy is applied to the vehicle at high speed. Based on the vehicle stability reference value, yaw rate is used to design the fuzzy controller to distribute the driving wheel torque. The simulation results show that the basic electronic differential speed function is realized based on the yaw moment control strategy, while the vehicle stability control is improved and the driving safety is enhanced. On the other hand, the torque control strategy can also assist steering of vehicle.

  15. Self-supervised dynamical systems

    International Nuclear Information System (INIS)

    Zak, Michail

    2004-01-01

    A new type of dynamical systems which capture the interactions via information flows typical for active multi-agent systems is introduced. The mathematical formalism is based upon coupling the classical dynamical system (with random components caused by uncertainties in initial conditions as well as by Langevin forces) with the corresponding Liouville or the Fokker-Planck equations describing evolution of these uncertainties in terms of probability density. The coupling is implemented by information-based supervising forces which fundamentally change the patterns of probability evolution. It is demonstrated that the probability density can approach prescribed attractors while exhibiting such patterns as shock waves, solitons and chaos in probability space. Applications of these phenomena to information-based neural nets, expectation-based cooperation, self-programmed systems, control chaos using terminal attractors as well as to games with incomplete information, are addressed. A formal similarity between the mathematical structure of the introduced dynamical systems and quantum mechanics is discussed

  16. Robust Frequency and Voltage Stability Control Strategy for Standalone AC/DC Hybrid Microgrid

    Directory of Open Access Journals (Sweden)

    Furqan Asghar

    2017-05-01

    Full Text Available The microgrid (MG concept is attracting considerable attention as a solution to energy deficiencies, especially in remote areas, but the intermittent nature of renewable sources and varying loads cause many control problems and thereby affect the quality of power within a microgrid operating in standalone mode. This might cause large frequency and voltage deviations in the system due to unpredictable output power fluctuations. Furthermore, without any main grid support, it is more complex to control and manage the system. In past, droop control and various other coordination control strategies have been presented to stabilize the microgrid frequency and voltages, but in order to utilize the available resources up to their maximum capacity in a positive way, new and robust control mechanisms are required. In this paper, a standalone microgrid is presented, which integrates renewable energy-based distributed generations and local loads. A fuzzy logic-based intelligent control technique is proposed to maintain the frequency and DC (direct current-link voltage stability for sudden changes in load or generation power. Also from a frequency control perspective, a battery energy storage system (BESS is suggested as a replacement for a synchronous generator to stabilize the nominal system frequency as a synchronous generator is unable to operate at its maximum efficiency while being controlled for stabilization purposes. Likewise, a super capacitor (SC and BESS is used to stabilize DC bus voltages even though maximum possible energy is being extracted from renewable generated sources using maximum power point tracking. This newly proposed control method proves to be effective by reducing transient time, minimizing the frequency deviations, maintaining voltages even though maximum power point tracking is working and preventing generators from exceeding their power ratings during disturbances. However, due to the BESS limited capacity, load switching

  17. Investigation of electrodynamic stabilization and control of long orbiting tethers

    Science.gov (United States)

    Colombo, G.; Arnold, D.

    1984-01-01

    The state-of-the-art in tether modelling among participants in the Tethered Satellite System (TSS) Program, the slack tether and its behavior, and certain advanced applications of the tether to problems in orbital mechanics are identified. The features and applications of the TSS software set are reviewed. Modelling the slack tether analytically with as many as 50 mass points and the application of this new model to a study of the behavior of a broken tether near the Shuttle are described. A reel control algorithm developed by SAO and examples of its use are described, including an example which also demonstrates the use of the tether in transferring a heavy payload from a low-orbiting Shuttle to a high circular orbit. Capture of a low-orbiting payload by a Space Station in high circular orbit is described. Energy transfer within a dumbbell-type spacecraft by cyclical reeling operations or gravitational effects on the natural elasticity of the connecting tether, it is shown, can circularize the orbit of the spacecraft.

  18. Adaptive Neural-Sliding Mode Control of Active Suspension System for Camera Stabilization

    Directory of Open Access Journals (Sweden)

    Feng Zhao

    2015-01-01

    Full Text Available The camera always suffers from image instability on the moving vehicle due to the unintentional vibrations caused by road roughness. This paper presents a novel adaptive neural network based on sliding mode control strategy to stabilize the image captured area of the camera. The purpose is to suppress vertical displacement of sprung mass with the application of active suspension system. Since the active suspension system has nonlinear and time varying characteristics, adaptive neural network (ANN is proposed to make the controller robustness against systematic uncertainties, which release the model-based requirement of the sliding model control, and the weighting matrix is adjusted online according to Lyapunov function. The control system consists of two loops. The outer loop is a position controller designed with sliding mode strategy, while the PID controller in the inner loop is to track the desired force. The closed loop stability and asymptotic convergence performance can be guaranteed on the basis of the Lyapunov stability theory. Finally, the simulation results show that the employed controller effectively suppresses the vibration of the camera and enhances the stabilization of the entire camera, where different excitations are considered to validate the system performance.

  19. Supervised Transfer Sparse Coding

    KAUST Repository

    Al-Shedivat, Maruan

    2014-07-27

    A combination of the sparse coding and transfer learn- ing techniques was shown to be accurate and robust in classification tasks where training and testing objects have a shared feature space but are sampled from differ- ent underlying distributions, i.e., belong to different do- mains. The key assumption in such case is that in spite of the domain disparity, samples from different domains share some common hidden factors. Previous methods often assumed that all the objects in the target domain are unlabeled, and thus the training set solely comprised objects from the source domain. However, in real world applications, the target domain often has some labeled objects, or one can always manually label a small num- ber of them. In this paper, we explore such possibil- ity and show how a small number of labeled data in the target domain can significantly leverage classifica- tion accuracy of the state-of-the-art transfer sparse cod- ing methods. We further propose a unified framework named supervised transfer sparse coding (STSC) which simultaneously optimizes sparse representation, domain transfer and classification. Experimental results on three applications demonstrate that a little manual labeling and then learning the model in a supervised fashion can significantly improve classification accuracy.

  20. Simple Model-Free Controller for the Stabilization of Planetary Inverted Pendulum

    Directory of Open Access Journals (Sweden)

    Huanhuan Mai

    2012-01-01

    Full Text Available A simple model-free controller is presented for solving the nonlinear dynamic control problems. As an example of the problem, a planetary gear-type inverted pendulum (PIP is discussed. To control the inherently unstable system which requires real-time control responses, the design of a smart and simple controller is made necessary. The model-free controller proposed includes a swing-up controller part and a stabilization controller part; neither controller has any information about the PIP. Since the input/output scaling parameters of the fuzzy controller are highly sensitive, we use genetic algorithm (GA to obtain the optimal control parameters. The experimental results show the effectiveness and robustness of the present controller.

  1. Advanced Music Therapy Supervision Training

    DEFF Research Database (Denmark)

    Pedersen, Inge Nygaard

    2009-01-01

    supervision training excerpts live in the workshop will be offered. The workshop will include demonstrating a variety of supervision methods and techniques used in A) post graduate music therapy training programs b) a variety of work contexts such as psychiatry and somatic music psychotherapy. The workshop......The presentation will illustrate training models in supervision for experienced music therapists where transference/counter transference issues are in focus. Musical, verbal and body related tools will be illustrated from supervision practice by the presenters. A possibility to experience small...

  2. Learning Dynamics in Doctoral Supervision

    DEFF Research Database (Denmark)

    Kobayashi, Sofie

    investigates learning opportunities in supervision with multiple supervisors. This was investigated through observations and recording of supervision, and subsequent analysis of transcripts. The analyses used different perspectives on learning; learning as participation, positioning theory and variation theory....... The research illuminates how learning opportunities are created in the interaction through the scientific discussions. It also shows how multiple supervisors can contribute to supervision by providing new perspectives and opinions that have a potential for creating new understandings. The combination...... of different theoretical frameworks from the perspectives of learning as individual acquisition and a sociocultural perspective on learning contributed to a nuanced illustration of the otherwise implicit practices of supervision....

  3. Feedback stabilization of controlled dynamical systems in honor of Laurent Praly

    CERN Document Server

    2017-01-01

    This book is a tribute to Professor Laurent Praly and follows on from a workshop celebrating the occasion of his 60th birthday. It presents new and unified visions of the numerous problems that Laurent Praly has worked on in his prolific career: adaptive control, output feedback and observers, stability and stabilization. His main contributions are the central topic of this book. The book collects contributions written by prominent international experts in the control community, addressing a rich variety of topics: emerging ideas, advanced applications, and theoretical concepts. Organized in three sections, the first section covers the field of adaptive control, where Laurent Praly started his career. The second section focuses on stabilization and output feedback, which is also the topic of the second half of his career. Lastly, the third section presents the emerging research that will form Laurent Praly’s scientific legacy.

  4. Thermodynamic stability of driven open systems and control of phase separation by electro-autocatalysis.

    Science.gov (United States)

    Bazant, Martin Z

    2017-07-01

    Motivated by the possibility of electrochemical control of phase separation, a variational theory of thermodynamic stability is developed for driven reactive mixtures, based on a nonlinear generalization of the Cahn-Hilliard and Allen-Cahn equations. The Glansdorff-Prigogine stability criterion is extended for driving chemical work, based on variations of nonequilibrium Gibbs free energy. Linear stability is generally determined by the competition of chemical diffusion and driven autocatalysis. Novel features arise for electrochemical systems, related to controlled total current (galvanostatic operation), concentration-dependent exchange current (Butler-Volmer kinetics), and negative differential reaction resistance (Marcus kinetics). The theory shows how spinodal decomposition can be controlled by solo-autocatalytic charge transfer, with only a single faradaic reaction. Experimental evidence is presented for intercalation and electrodeposition in rechargeable batteries, and further applications are discussed in solid state ionics, electrovariable optics, electrochemical precipitation, and biological pattern formation.

  5. Improved Polynomial Fuzzy Modeling and Controller with Stability Analysis for Nonlinear Dynamical Systems

    Directory of Open Access Journals (Sweden)

    Hamed Kharrati

    2012-01-01

    Full Text Available This study presents an improved model and controller for nonlinear plants using polynomial fuzzy model-based (FMB systems. To minimize mismatch between the polynomial fuzzy model and nonlinear plant, the suitable parameters of membership functions are determined in a systematic way. Defining an appropriate fitness function and utilizing Taylor series expansion, a genetic algorithm (GA is used to form the shape of membership functions in polynomial forms, which are afterwards used in fuzzy modeling. To validate the model, a controller based on proposed polynomial fuzzy systems is designed and then applied to both original nonlinear plant and fuzzy model for comparison. Additionally, stability analysis for the proposed polynomial FMB control system is investigated employing Lyapunov theory and a sum of squares (SOS approach. Moreover, the form of the membership functions is considered in stability analysis. The SOS-based stability conditions are attained using SOSTOOLS. Simulation results are also given to demonstrate the effectiveness of the proposed method.

  6. Advanced controls for stability assessment of solar dynamics space power generation

    Science.gov (United States)

    Momoh, James A.; Anwah, Nnamdi A.

    1995-01-01

    In support of the power requirements for the Space Station Alpha (SSA), a joint program by the U.S. and Russia for a permanently manned space station to be launched into orbit by 1998, a robust control scheme is needed to assure the stability of the rotating machines that will be integrated into the power subsystem. A framework design and systems studies for modeling and analysis is presented. It employs classical d-q axes machine model with voltage/frequency dependent loads. To guarantee that design requirements and necessary trade studies are done, a functional analysis tool CORE is used for the study. This provides us with different control options for stability assessment. Initial studies and recommendations using advanced simulation tools are also presented. The benefits of the stability/control scheme for evaluating future designs and power management are discussed.

  7. Stabilizing Planar Inverted Pendulum System Based on Fuzzy Nine-point Controller

    OpenAIRE

    Qi Qian; Liu Feng; Tang Yong-chuan; Yang Yang

    2013-01-01

    In order to stabilize planar inverted pendulum, after analyzing the physical characteristics of the planar inverted pendulum system, a pendulum nine-point controller and a car nine-point controller for X-axis and Y-axis were designed respectively. Then a fuzzy coordinator was designed using the fuzzy control theory based on the priority of those two controllers, and the priority level of the pendulum is higher than the car. Thus, the control tasks of each controller in each axis were harmoniz...

  8. Robust Stability Analysis of the Space Launch System Control Design: A Singular Value Approach

    Science.gov (United States)

    Pei, Jing; Newsome, Jerry R.

    2015-01-01

    Classical stability analysis consists of breaking the feedback loops one at a time and determining separately how much gain or phase variations would destabilize the stable nominal feedback system. For typical launch vehicle control design, classical control techniques are generally employed. In addition to stability margins, frequency domain Monte Carlo methods are used to evaluate the robustness of the design. However, such techniques were developed for Single-Input-Single-Output (SISO) systems and do not take into consideration the off-diagonal terms in the transfer function matrix of Multi-Input-Multi-Output (MIMO) systems. Robust stability analysis techniques such as H(sub infinity) and mu are applicable to MIMO systems but have not been adopted as standard practices within the launch vehicle controls community. This paper took advantage of a simple singular-value-based MIMO stability margin evaluation method based on work done by Mukhopadhyay and Newsom and applied it to the SLS high-fidelity dynamics model. The method computes a simultaneous multi-loop gain and phase margin that could be related back to classical margins. The results presented in this paper suggest that for the SLS system, traditional SISO stability margins are similar to the MIMO margins. This additional level of verification provides confidence in the robustness of the control design.

  9. Assessment of effect of SSSC stabilizer in different control channels on damping inter-area oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Shakarami, M.R., E-mail: shakarami@iust.ac.i [Centre of Excellence for Power System Automation and Operation, Department of Electrical Engineering, Iran University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of); Kazemi, A. [Centre of Excellence for Power System Automation and Operation, Department of Electrical Engineering, Iran University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of)

    2011-03-15

    A static synchronous series compensator (SSSC) is one of the series flexible ac transmission system (FACTS) devices that injects a balanced three-phase voltage in quadrature with the transmission line current. There are two channels for controlling of phase and magnitude of the voltage. When the SSSC is used for damping of inter-area oscillations, a SSSC-based stabilizer can be included in both channels. In this paper, the best location and suitable input control signal for SSSC in order to enhance the damping of inter-area oscillations are selected by residue analysis. A method by quadratic mathematic programming has been presented to the design of the stabilizer. By this method, the effect of the stabilizer in both control channels of the SSSC on damping of inter-area oscillations has been assessed. By considering the gain of stabilizer as a criterion, obtained results from studying on a small and a large multi-machine power system show that the stabilizer in the phase control channel is more effective for damping inter-are oscillations.

  10. Stability of the spreading in small-world network with predictive controller

    International Nuclear Information System (INIS)

    Bao, Z.J.; Jiang, Q.Y.; Yan, W.J.; Cao, Y.J.

    2010-01-01

    In this Letter, we apply the predictive control strategy to suppress the propagation of diseases or viruses in small-world network. The stability of small-world spreading model with predictive controller is investigated. The sufficient and necessary stability condition is given, which is closely related to the controller parameters and small-world rewiring probability p. Our simulations discover a phenomenon that, with the fixed predictive controller parameters, the spreading dynamics become more and more stable when p decreases from a larger value to a smaller one, and the suitable controller parameters can effectively suppress the spreading behaviors even when p varies within the whole spectrum, and the unsuitable controller parameters can lead to oscillation when p lies within a certain range.

  11. Nonlinear Feedback Control and Stability Analysis of a Proof-of-Work Blockchain

    Directory of Open Access Journals (Sweden)

    Geir Hovland

    2017-10-01

    Full Text Available In this paper a novel feedback controller and stability analysis of a blockchain implementation is developed by using a control engineering perspective. The controller output equals the difficulty adjustment in the mining process while the feedback variable is the average block time over a certain time period. The computational power (hash rate of the miners is considered a disturbance in the model. The developed controller is tested against a simulation model with constant disturbance, step and ramp responses as well as with a high-frequency sinusoidal disturbance. Stability and a fast response is demonstrated in all these cases with a controller which adjusts it's output at every new block. Finally the performance of the controller is implemented and demonstrated on a testnet with a constant hash rate as well as on the mainnet of a public open source blockchain project.

  12. A novel vehicle dynamics stability control algorithm based on the hierarchical strategy with constrain of nonlinear tyre forces

    Science.gov (United States)

    Li, Liang; Jia, Gang; Chen, Jie; Zhu, Hongjun; Cao, Dongpu; Song, Jian

    2015-08-01

    Direct yaw moment control (DYC), which differentially brakes the wheels to produce a yaw moment for the vehicle stability in a steering process, is an important part of electric stability control system. In this field, most control methods utilise the active brake pressure with a feedback controller to adjust the braked wheel. However, the method might lead to a control delay or overshoot because of the lack of a quantitative project relationship between target values from the upper stability controller to the lower pressure controller. Meanwhile, the stability controller usually ignores the implementing ability of the tyre forces, which might be restrained by the combined-slip dynamics of the tyre. Therefore, a novel control algorithm of DYC based on the hierarchical control strategy is brought forward in this paper. As for the upper controller, a correctional linear quadratic regulator, which not only contains feedback control but also contains feed forward control, is introduced to deduce the object of the stability yaw moment in order to guarantee the yaw rate and side-slip angle stability. As for the medium and lower controller, the quantitative relationship between the vehicle stability object and the target tyre forces of controlled wheels is proposed to achieve smooth control performance based on a combined-slip tyre model. The simulations with the hardware-in-the-loop platform validate that the proposed algorithm can improve the stability of the vehicle effectively.

  13. Controls on hillslope stability in a mountain river catchment

    Science.gov (United States)

    Golly, Antonius; Turowski, Jens; Hovius, Niels; Badoux, Alexandre

    2015-04-01

    Sediment transport in fluvial systems accounts for a large fraction of natural hazard damage costs in mountainous regions and is an important factor for risk mitigation, engineering and ecology. Although sediment transport in high-gradient channels gathered research interest over the last decades, sediment dynamics in steep streams are generally not well understood. For instance, the sourcing of the sediment and when and how it is actually mobilized is largely undescribed. In the Erlenbach, a mountain torrent in the Swiss Prealps, we study the mechanistic relations between in-channel hydrology, channel morphology, external climatic controls and the surrounding sediment sources to identify relevant process domains for sediment input and their characteristic scales. Here, we analyze the motion of a slow-moving landslide complex that was permanently monitored by time-lapse cameras over a period of 70 days at a 30 minutes interval. In addition, data sets for stream discharge, air temperature and precipitation rates are available. Apparent changes in the channel morphology, e.g. the destruction of channel-spanning bed forms, were manually determined from the time-lapse images and were treated as event marks in the time series. We identify five relevant types of sediment displacement processes emerging during the hillslope motion: concentrated mud flows, deep seated hillslope failure, catastrophic cavity failure, hillslope bank erosion and individual grain loss. Generally, sediment displacement occurs on a large range of temporal and spatial scales and sediment dynamics in steep streams not only depend on large floods with long recurrence intervals. We find that each type of displacement acts in a specific temporal and spatial domain with their characteristic scales. Different external climatic forcing (e.g. high-intensity vs. long-lasting precipitation events) promote different displacement processes. Stream morphology and the presence of boulders have a large effect on

  14. Public Supervision over Private Relationships : Towards European Supervision Private Law?

    NARCIS (Netherlands)

    Cherednychenko, O.O.

    2014-01-01

    The rise of public supervision over private relationships in many areas of private law has led to the development of what, in the author’s view, could be called ‘European supervision private law’. This emerging body of law forms part of European regulatory private law and is made up of

  15. On the internal stability of non-linear dynamic inversion: application to flight control

    Czech Academy of Sciences Publication Activity Database

    Alam, M.; Čelikovský, Sergej

    2017-01-01

    Roč. 11, č. 12 (2017), s. 1849-1861 ISSN 1751-8644 R&D Projects: GA ČR(CZ) GA17-04682S Institutional support: RVO:67985556 Keywords : flight control * non-linear dynamic inversion * stability Subject RIV: BC - Control Systems Theory OBOR OECD: Automation and control systems Impact factor: 2.536, year: 2016 http://library.utia.cas.cz/separaty/2017/TR/celikovsky-0476150.pdf

  16. Global stabilization of linear continuous time-varying systems with bounded controls

    International Nuclear Information System (INIS)

    Phat, V.N.

    2004-08-01

    This paper deals with the problem of global stabilization of a class of linear continuous time-varying systems with bounded controls. Based on the controllability of the nominal system, a sufficient condition for the global stabilizability is proposed without solving any Riccati differential equation. Moreover, we give sufficient conditions for the robust stabilizability of perturbation/uncertain linear time-varying systems with bounded controls. (author)

  17. Dynamic stability control in forward falls: postural corrections after muscle fatigue in young and older adults.

    Science.gov (United States)

    Mademli, Lida; Arampatzis, Adamantios; Karamanidis, Kiros

    2008-06-01

    Many studies report that muscle strength loss may alter the human system's capacity to generate rapid force for balance corrections after perturbations, leading to deficient recovery behaviours. Yet little is known regarding the effect of modifications in the neuromuscular system induced by fatigue on dynamic stability control during postural perturbations. This study investigates the effect of muscle strength decline induced by fatiguing contractions on the dynamic stability control of young and older adults during forward falls. Eleven young and eleven older male adults had to regain balance after sudden falls before and after submaximal fatiguing knee extension-flexion contractions. Young subjects had a higher margin of stability than older ones before and after the fatiguing task. This reflects their enhanced ability in using mechanisms for maintaining dynamic stability (i.e. a greater base of support). The margin of stability, the boundary of the base of support and the position of the extrapolated centre of mass, remained unaffected by the reduction in muscle strength induced by the fatiguing contractions, indicating an appropriate adjustment of the motor commands to compensate the deficit in muscle strength. Both young and older adults were able to counteract the decreased horizontal ground reaction forces after the fatiguing task by flexing their knee to a greater extent, leading to similar decreases in the horizontal velocity of centre of mass as in the pre fatigue condition. The results demonstrate the ability of the central nervous system to rapidly modify the execution of postural corrections including mechanisms for maintaining dynamic stability.

  18. Optimization of a pressure control valve for high power automatic transmission considering stability

    Science.gov (United States)

    Jian, Hongchao; Wei, Wei; Li, Hongcai; Yan, Qingdong

    2018-02-01

    The pilot-operated electrohydraulic clutch-actuator system is widely utilized by high power automatic transmission because of the demand of large flowrate and the excellent pressure regulating capability. However, a self-excited vibration induced by the inherent non-linear characteristics of valve spool motion coupled with the fluid dynamics can be generated during the working state of hydraulic systems due to inappropriate system parameters, which causes sustaining instability in the system and leads to unexpected performance deterioration and hardware damage. To ensure a stable and fast response performance of the clutch actuator system, an optimal design method for the pressure control valve considering stability is proposed in this paper. A non-linear dynamic model of the clutch actuator system is established based on the motion of the valve spool and coupling fluid dynamics in the system. The stability boundary in the parameter space is obtained by numerical stability analysis. Sensitivity of the stability boundary and output pressure response time corresponding to the valve parameters are identified using design of experiment (DOE) approach. The pressure control valve is optimized using particle swarm optimization (PSO) algorithm with the stability boundary as constraint. The simulation and experimental results reveal that the optimization method proposed in this paper helps in improving the response characteristics while ensuring the stability of the clutch actuator system during the entire gear shift process.

  19. Carrier-envelope phase stabilization and control using a transmission grating compressor and an AOPDF.

    Science.gov (United States)

    Canova, Lorenzo; Chen, Xiaowei; Trisorio, Alexandre; Jullien, Aurélie; Assion, Andreas; Tempea, Gabriel; Forget, Nicolas; Oksenhendler, Thomas; Lopez-Martens, Rodrigo

    2009-05-01

    Carrier-envelope phase (CEP) stabilization of a femtosecond chirped-pulse amplification system featuring a compact transmission grating compressor is demonstrated. The system includes two amplification stages and routinely generates phase-stable (approximately 250 mrad rms) 2 mJ, 25 fs pulses at 1 kHz. Minimizing the optical pathway in the compressor enables phase stabilization without feedback control of the grating separation or beam pointing. We also demonstrate for the first time to the best of our knowledge, out-of-loop control of the CEP using an acousto-optic programmable dispersive filter inside the laser chain.

  20. A new strategy for transient stability using augmented generator control and local dynamic braking

    Energy Technology Data Exchange (ETDEWEB)

    Dorsey, J; Jiang, H; Habetler, T [Georgia Inst. of Tech., Atlanta, GA (United States); Qu, Z [University of Central Florida, Orlando, FL (United States)

    1994-12-31

    A decentralized automatic control strategy for significantly improving the transient stability of a large power system is introduced. The strategy combines local dynamic braking and a straightforward augmentation of the existing turbine / governor control system that uses only local feedback. The brake resistor, which employs thick film, metal oxide technology, has no inductance and is of very low resistance, allowing its use during fault to show a generator`s acceleration. Simulation results using the 39 Bus New England system show that the strategy dramatically increases the global stability of a power system. (author) 15 refs., 7 figs., 1 tab.

  1. Automatic approach to stabilization and control for multi robot teams by multilayer network operator

    Directory of Open Access Journals (Sweden)

    Diveev Askhat

    2016-01-01

    Full Text Available The paper describes a novel methodology for synthesis a high-level control of autonomous multi robot teams. The approach is based on multilayer network operator method that belongs to a symbolic regression class. Synthesis is accomplished in three steps: stabilizing robots about some given position in a state space, finding optimal trajectories of robots’ motion as sets of stabilizing points and then approximating all the points of optimal trajectories by some multi-dimensional function of state variables. The feasibility and effectiveness of the proposed approach is verified on simulations of the task of control synthesis for three mobile robots parking in the constrained space.

  2. Sliding Mode Controller and Lyapunov Redesign Controller to Improve Microgrid Stability: A Comparative Analysis with CPL Power Variation

    Directory of Open Access Journals (Sweden)

    Eklas Hossain

    2017-11-01

    Full Text Available To mitigate the microgrid instability despite the presence of dense Constant Power Load (CPL loads in the system, a number of compensation techniques have already been gone through extensive research, proposed, and implemented around the world. In this paper, a storage based load side compensation technique is used to enhance stability of microgrids. Besides adopting this technique here, Sliding Mode Controller (SMC and Lyapunov Redesign Controller (LRC, two of the most prominent nonlinear control techniques, are individually implemented to control microgrid system stability with desired robustness. CPL power is then varied to compare robustness of these two control techniques. This investigation revealed the better performance of the LRC system compared to SMC to retain stability in microgrid with dense CPL load. All the necessary results are simulated in Matlab/Simulink platform for authentic verification. Reasons behind inferior SMC performance and ways to mitigate that are also discussed. Finally, the effectiveness of SMC and LRC systems to attain stability in real microgrids is verified by numerical analysis.

  3. Proportional Load Sharing and Stability of DC Microgrid with Distributed Architecture Using SM Controller

    Directory of Open Access Journals (Sweden)

    Muhammad Rashad

    2018-01-01

    Full Text Available DC microgrids look attractive in distribution systems due to their high reliability, high efficiency, and easy integration with renewable energy sources. The key objectives of the DC microgrid include proportional load sharing and precise voltage regulation. Droop controllers are based on decentralized control architectures which are not effective in achieving these objectives simultaneously due to the voltage error and load power variation. A centralized controller can achieve these objectives using a high speed communication link. However, it loses reliability due to the single point failure. Additionally, these controllers are realized through proportional integral (PI controllers which cannot ensure load sharing and stability in all operating conditions. To address limitations, a distributed architecture using sliding mode (SM controller utilizing low bandwidth communication is proposed for DC microgrids in this paper. The main advantages are high reliability, load power sharing, and precise voltage regulation. Further, the SM controller shows high robustness, fast dynamic response, and good stability for large load variations. To analyze the stability and dynamic performance, a system model is developed and its transversality, reachability, and equivalent control conditions are verified. Furthermore, the dynamic behavior of the modeled system is investigated for underdamped and critically damped responses. Detailed simulations are carried out to show the effectiveness of the proposed controller.

  4. Fuzzy-Based Hybrid Control Algorithm for the Stabilization of a Tri-Rotor UAV.

    Science.gov (United States)

    Ali, Zain Anwar; Wang, Daobo; Aamir, Muhammad

    2016-05-09

    In this paper, a new and novel mathematical fuzzy hybrid scheme is proposed for the stabilization of a tri-rotor unmanned aerial vehicle (UAV). The fuzzy hybrid scheme consists of a fuzzy logic controller, regulation pole-placement tracking (RST) controller with model reference adaptive control (MRAC), in which adaptive gains of the RST controller are being fine-tuned by a fuzzy logic controller. Brushless direct current (BLDC) motors are installed in the triangular frame of the tri-rotor UAV, which helps maintain control on its motion and different altitude and attitude changes, similar to rotorcrafts. MRAC-based MIT rule is proposed for system stability. Moreover, the proposed hybrid controller with nonlinear flight dynamics is shown in the presence of translational and rotational velocity components. The performance of the proposed algorithm is demonstrated via MATLAB simulations, in which the proposed fuzzy hybrid controller is compared with the existing adaptive RST controller. It shows that our proposed algorithm has better transient performance with zero steady-state error, and fast convergence towards stability.

  5. Intelligent Control of UPFC for Enhancing Transient Stability on Multi-Machine Power Systems

    Directory of Open Access Journals (Sweden)

    Hassan Barati

    2010-01-01

    Full Text Available One of the benefit of FACTS devices is increase of stability in power systems with control active and reactive power at during the fault in power system. Although, the power system stabilizers (PSSs have been one of the most common controls used to damp out oscillations, this device may not produce enough damping especially to inter-area mode and therefore, there is an increasing interest in using FACTS devices to aid in damping of these oscillations. In This paper, UPFC is used for damping oscillations and to enhance the transient stability performance of power systems. The controller parameters are designed using an efficient version of the Takagi-Sugeno fuzzy control scheme. The function based Takagi-Sugeno-Kang (TSK fuzzy controller uses. For optimization parameters of fuzzy PI controller, the GA, PSO and HGAPSO algorithms are used. The computer simulation results, the effect of UPFC with conventional PI controller, fuzzy PI controller and intelligent controllers (GA, PSO and HGAPSO for damping the local-mode and inter-area mode of under large and small disturbances in the four-machine two-area power system evaluated and compared.

  6. Fuzzy Logic Based Control of the Lateral Stability of Tractor Semitrailer Vehicle

    Directory of Open Access Journals (Sweden)

    Xiujian Yang

    2015-01-01

    Full Text Available A novel control scheme is proposed to improve the yaw stability of a tractor semitrailer vehicle in critical situations. The control scheme is a two-layer structure consisting of an upper yaw moment controller and a lower brake force distributor. The tractor and the trailer are, respectively, stabilized by two independent fuzzy logic based yaw moment controllers. The controllers for the tractor and the trailer are, respectively, designed to track the reference yaw rate of the tractor and the hitch angle between the tractor and the trailer while considering the variation of the hitch angular rate at the same time. The corrective yaw moments determined by the corresponding upper fuzzy yaw moment controllers are realized by active wheel braking. The performance of the proposed control scheme is evaluated by simulations on a nonlinear vehicle model. The results demonstrate that the proposed control scheme is robust and effective in stabilizing the severe instabilities such as jackknife and trailer oscillation in the chosen simulation scenarios. It is believed that this control scheme is robust to the variation of road adhesion conditions.

  7. Exponential Stability of Time-Switched Two-Subsystem Nonlinear Systems with Application to Intermittent Control

    Directory of Open Access Journals (Sweden)

    Huang Tingwen

    2009-01-01

    Full Text Available This paper studies the exponential stability of a class of periodically time-switched nonlinear systems. Three cases of such systems which are composed, respectively, of a pair of unstable subsystems, of both stable and unstable subsystems, and of a pair of stable systems, are considered. For the first case, the proposed result shows that there exists periodically switching rule guaranteeing the exponential stability of the whole system with (sufficient small switching period if there is a Hurwitz linear convex combination of two uncertain linear systems derived from two subsystems by certain linearization. For the second case, we present two general switching criteria by means of multiple and single Lyapunov function, respectively. We also investigate the stability issue of the third case, and the switching criteria of exponential stability are proposed. The present results for the second case are further applied to the periodically intermittent control. Several numerical examples are also given to show the effectiveness of theoretical results.

  8. Stability and dynamics of a controlled van der Pol-Duffing oscillator

    International Nuclear Information System (INIS)

    Ji, J.C.; Hansen, C.H.

    2006-01-01

    The trivial equilibrium of a van der Pol-Duffing oscillator under a linear-plus-nonlinear feedback control may change its stability either via a single or via a double Hopf bifurcation if the time delay involved in the feedback reaches certain values. It is found that the trivial equilibrium may lose its stability via a subcritical or supercritical Hopf bifurcation and regain its stability via a reverse subcritical or supercritical Hopf bifurcation as the time delay increases. A stable limit cycle appears after a supercritical Hopf bifurcation occurs and disappears through a reverse supercritical Hopf bifurcation. The interaction of the weakly periodic excitation and the stable bifurcating solution is investigated for the forced system under primary resonance conditions. It is shown that the forced periodic response may lose its stability via a Neimark-Sacker bifurcation. Analytical results are validated by a comparison with those of direct numerical integration

  9. Postural stability and ankle sprain history in athletes compared to uninjured controls.

    Science.gov (United States)

    Huurnink, Arnold; Fransz, Duncan P; Kingma, Idsart; Verhagen, Evert A L M; van Dieën, Jaap H

    2014-02-01

    Diminished postural stability is a risk factor for ankle sprain occurrence and ankle sprains result in impaired postural stability. To date, ankle sprain history has not been taken into account as a determinant of postural stability, while it could possibly specify subgroups of interest. Postural stability was compared between 18 field hockey athletes who had recovered from an ankle sprain (mean (SD); 3.6 (1.5) months post-injury), and 16 uninjured controls. Force plate and kinematics parameters were calculated during single-leg standing: mean center of pressure speed, mean absolute horizontal ground reaction force, mean absolute ankle angular velocity, and mean absolute hip angular velocity. Additionally, cluster analysis was applied to the 'injured' participants, and the cluster with diminished postural stability was compared to the other participants with respect to ankle sprain history. MANCOVA showed no significant difference between groups in postural stability (P = 0.68). A self-reported history of an (partial) ankle ligament rupture was typically present in the cluster with diminished postural stability. Subsequently, a 'preceding rupture' was added as a factor in the MANCOVA, which showed a significant association between diminished postural stability and a 'preceding rupture' (P = 0.01), for all four individual parameters (P: 0.001-0.029; Cohen's d: 0.96-2.23). Diminished postural stability is not apparent in all previously injured athletes. However, our analysis suggests that an (mild) ankle sprain with a preceding severe ankle sprain is associated with impaired balance ability. Therefore, sensorimotor training may be emphasized in this particular group and caution is warranted in return to play decisions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Enhancing the stabilization of aircraft pitch motion control via intelligent and classical method

    Science.gov (United States)

    Lukman, H.; Munawwarah, S.; Azizan, A.; Yakub, F.; Zaki, S. A.; Rasid, Z. A.

    2017-12-01

    The pitching movement of an aircraft is very important to ensure passengers are intrinsically safe and the aircraft achieve its maximum stability. The equations governing the motion of an aircraft are a complex set of six nonlinear coupled differential equations. Under certain assumptions, it can be decoupled and linearized into longitudinal and lateral equations. Pitch control is a longitudinal problem and thus, only the longitudinal dynamics equations are involved in this system. It is a third order nonlinear system, which is linearized about the operating point. The system is also inherently unstable due to the presence of a free integrator. Because of this, a feedback controller is added in order to solve this problem and enhance the system performance. This study uses two approaches in designing controller: a conventional controller and an intelligent controller. The pitch control scheme consists of proportional, integral and derivatives (PID) for conventional controller and fuzzy logic control (FLC) for intelligent controller. Throughout the paper, the performance of the presented controllers are investigated and compared based on the common criteria of step response. Simulation results have been obtained and analysed by using Matlab and Simulink software. The study shows that FLC controller has higher ability to control and stabilize the aircraft's pitch angle as compared to PID controller.

  11. Tracking performance and global stability guaranteed neural control of uncertain hypersonic flight vehicle

    Directory of Open Access Journals (Sweden)

    Tao Teng

    2016-02-01

    Full Text Available In this article, a global adaptive neural dynamic surface control with predefined tracking performance is developed for a class of hypersonic flight vehicles, whose accurate dynamics is hard to obtain. The control scheme developed in this paper overcomes the limitations of neural approximation region by employing a switching mechanism which incorporates an additional robust controller outside the neural approximation region to pull the transient state variables back when they overstep the neural approximation region, such that globally uniformly ultimately bounded stability can be guaranteed. Especially, the developed global adaptive neural control also improves the tracking performance by introducing an error transformation mechanism, such that both transient and steady-state performance can be shaped according to the predefined bounds. Simulation studies on the hypersonic flight vehicle validate that the designed controller has good velocity modulation and velocity stability performance.

  12. Design of Launch Vehicle Flight Control Systems Using Ascent Vehicle Stability Analysis Tool

    Science.gov (United States)

    Jang, Jiann-Woei; Alaniz, Abran; Hall, Robert; Bedossian, Nazareth; Hall, Charles; Jackson, Mark

    2011-01-01

    A launch vehicle represents a complicated flex-body structural environment for flight control system design. The Ascent-vehicle Stability Analysis Tool (ASAT) is developed to address the complicity in design and analysis of a launch vehicle. The design objective for the flight control system of a launch vehicle is to best follow guidance commands while robustly maintaining system stability. A constrained optimization approach takes the advantage of modern computational control techniques to simultaneously design multiple control systems in compliance with required design specs. "Tower Clearance" and "Load Relief" designs have been achieved for liftoff and max dynamic pressure flight regions, respectively, in the presence of large wind disturbances. The robustness of the flight control system designs has been verified in the frequency domain Monte Carlo analysis using ASAT.

  13. Offshore Wind Farms and HVDC Grids Modeling as a Feedback Control System for Stability Analysis

    DEFF Research Database (Denmark)

    Bidadfar, Ali; Saborío-Romano, Oscar; Altin, Müfit

    The low impedance characteristics of DC transmission lines cause the voltage source converter (VSC) in HVDC networks to become electrically closer together and increase the risk of severe interactions between the converters. Such interactions, in turn, intensify the implementation of the grid...... control schemes and may lead the entire system to instability. Assessing the stability and adopting complex coordinated control schemes in an HVDC grid and wind farm turbines are challenging and require a precise model of the HVDC grid, wind farm, and the controllers. In this paper, a linear multivariable...... feedback control system (FCS) model is proposed to represent the dynamic characteristics of HVDC grids and their controllers. The FCS model can be used for different dynamic analyses in time and frequency domains. Moreover, using the FCS model the system stability is analyzed in both open- and closed...

  14. Robust Stabilization of Fractional-Order Systems with Interval Uncertainties via Fractional-Order Controllers

    Directory of Open Access Journals (Sweden)

    Sayyad Delshad Saleh

    2010-01-01

    Full Text Available Abstract We propose a fractional-order controller to stabilize unstable fractional-order open-loop systems with interval uncertainty whereas one does not need to change the poles of the closed-loop system in the proposed method. For this, we will use the robust stability theory of Fractional-Order Linear Time Invariant (FO-LTI systems. To determine the control parameters, one needs only a little knowledge about the plant and therefore, the proposed controller is a suitable choice in the control of interval nonlinear systems and especially in fractional-order chaotic systems. Finally numerical simulations are presented to show the effectiveness of the proposed controller.

  15. Accreditation to supervise research

    International Nuclear Information System (INIS)

    Mauclaire, Laurent

    2003-01-01

    After a recall of his academic research works, an indication of all his publications and of his teaching and research supervising activities, and a summary of his scientific activity, the author proposes an overview of his research works which addressed the study of radio-tracers for nuclear medicine, and the study of the 2,6 dimethyl beta cyclodextrin. These both topics are then more precisely presented and discussed. For the first one, the author notably studied iodine radiochemistry, and the elaboration of new compounds for dopamine recapturing visualization (development of radio-pharmaceutical drug marked with technetium). For the second one, the author reports the use of modified cyclodextrins for the transport of lipophilic radio-tracers

  16. Stabilization of business cycles of finance agents using nonlinear optimal control

    Science.gov (United States)

    Rigatos, G.; Siano, P.; Ghosh, T.; Sarno, D.

    2017-11-01

    Stabilization of the business cycles of interconnected finance agents is performed with the use of a new nonlinear optimal control method. First, the dynamics of the interacting finance agents and of the associated business cycles is described by a modeled of coupled nonlinear oscillators. Next, this dynamic model undergoes approximate linearization round a temporary operating point which is defined by the present value of the system's state vector and the last value of the control inputs vector that was exerted on it. The linearization procedure is based on Taylor series expansion of the dynamic model and on the computation of Jacobian matrices. The modelling error, which is due to the truncation of higher-order terms in the Taylor series expansion is considered as a disturbance which is compensated by the robustness of the control loop. Next, for the linearized model of the interacting finance agents, an H-infinity feedback controller is designed. The computation of the feedback control gain requires the solution of an algebraic Riccati equation at each iteration of the control algorithm. Through Lyapunov stability analysis it is proven that the control scheme satisfies an H-infinity tracking performance criterion, which signifies elevated robustness against modelling uncertainty and external perturbations. Moreover, under moderate conditions the global asymptotic stability features of the control loop are proven.

  17. Observer enhanced control for spin-stabilized tethered formation in earth orbit

    Science.gov (United States)

    Guang, Zhai; Yuyang, Li; Liang, Bin

    2018-04-01

    This paper addresses the issues relevant to control of spin-stabilized tethered formation in circular orbit. Due to the dynamic complexities and nonlinear perturbations, it is challenging to promote the control precision for the formation deployment and maintenance. In this work, the formation dynamics are derived with considering the spinning rate of the central body, then major attention is dedicated to develop the nonlinear disturbance observer. To achieve better control performance, the observer-enhanced controller is designed by incorporating the disturbance observer into the control loop, benefits from the disturbance compensation are demonstrated, and also, the dependences of the disturbance observer performance on some important parameters are theoretically and numerically analyzed.

  18. Stabilization Using a Discrete Fuzzy PDC Control with PID Controllers and Pole Placement: Application to an Experimental Greenhouse

    Directory of Open Access Journals (Sweden)

    Amine Chouchaine

    2011-01-01

    Full Text Available This paper proposes a control strategy for complex and nonlinear systems, based on a parallel distributed compensation (PDC controller. A solution is presented to solve a stability problem that arises when dealing with a Takagi-Sugeno discrete system with great numbers of rules. The PDC controller will use a classical controller like a PI, PID, or RST in each rule with a pole placement strategy to avoid causing instability. The fuzzy controller presented combines the multicontrol approach and the performance of the classical controllers to obtain a robust nonlinear control action that can also deal with time-variant systems. The presented method was applied to a small greenhouse to control its inside temperature by variation in ventilation rate inside the process. The results obtained will show the efficiency of the adopted method to control the nonlinear and complex systems.

  19. Medical supervision of radiation workers

    International Nuclear Information System (INIS)

    Santani, S.B.; Nandakumar, A.N.; Subramanian, G.

    1982-01-01

    The basic elements of an occupational medical supervision programme for radiation workers are very much the same as those relevant to other professions with some additional special features. This paper cites examples from literature and recommends measures such as spot checks and continuance of medical supervision even after a radiation worker leaves this profession. (author)

  20. Tværfaglig supervision

    DEFF Research Database (Denmark)

    Tværfaglig supervision dækker over supervision af forskellige faggrupper. Det er en kompleks disciplin der stiller store krav tl supervisor. Bogens første del præsenterer fire faglige supervisionsmodeller: En almen, en psykodynamisk, en kognitiv adfærdsterapeutisk og en narrativ. Anden del...

  1. Assessment of Counselors' Supervision Processes

    Science.gov (United States)

    Ünal, Ali; Sürücü, Abdullah; Yavuz, Mustafa

    2013-01-01

    The aim of this study is to investigate elementary and high school counselors' supervision processes and efficiency of their supervision. The interview method was used as it was thought to be better for realizing the aim of the study. The study group was composed of ten counselors who were chosen through purposeful sampling method. Data were…

  2. Robust Stability and H∞ Control of Uncertain Piecewise Linear Switched Systems with Filippov Solutions

    DEFF Research Database (Denmark)

    Ahmadi, Mohamadreza; Mojallali, Hamed; Wisniewski, Rafal

    2012-01-01

    This paper addresses the robust stability and control problem of uncertain piecewise linear switched systems where, instead of the conventional Carathe ́odory solutions, we allow for Filippov solutions. In other words, in contrast to the previous studies, solutions with infinite switching in fini...... algorithm is proposed to surmount the aforementioned matrix inequality conditions....... time along the facets and on faces of arbitrary dimensions are also taken into account. Firstly, based on earlier results, the stability problem of piecewise linear systems with Filippov solutions is translated into a number of linear matrix inequality feasibility tests. Subsequently, a set of matrix...... inequalities are brought forward, which determines the asymptotic stability of the Filippov solutions of a given uncertain piecewise linear system. Afterwards, bilinear matrix inequality conditions for synthesizing a robust controller with a guaranteed H∞ per- formance are formulated. Finally, a V-K iteration...

  3. Asymptotic stability and disturbance attenuation properties for a class of networked control systems

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this paper, stability and disturbance attenuation issues for a class of Networked Control Systems (NCSs)under uncertain access delay and packet dropout effects are considered. Our aim is to find conditions on the delay and packet dropout rate, under which the system stability and H∞ disturbance attenuation properties are preserved to a desired level. The basic idea in this paper is to formulate such Networked Control System as a discrete-time switched system. Then the NCSs' stability and performance problems can be reduced to the corresponding problems for switched systems, which have been studied for decades and for which a number of results are available in the literature. The techniques in this paper are based on recent progress in the discrete-time switched systems and piecewise Lyapunov functions.

  4. Stability Control of Force-Reflected Nonlinear Multilateral Teleoperation System under Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    Da Sun

    2016-01-01

    Full Text Available A novel control algorithm based on the modified wave-variable controllers is proposed to achieve accurate position synchronization and reasonable force tracking of the nonlinear single-master-multiple-slave teleoperation system and simultaneously guarantee overall system’s stability in the presence of large time-varying delays. The system stability in different scenarios of human and environment situations has been analyzed. The proposed method is validated through experimental work based on the 3-DOF trilateral teleoperation system consisting of three different manipulators. The experimental results clearly demonstrate the feasibility of the proposed algorithm to achieve high transparency and robust stability in nonlinear single-master-multiple-slave teleoperation system in the presence of time-varying delays.

  5. A Study of Supervision of China's Commercial Banks from the Perspective of the Trinity-Characteristics of Bank Supervision System

    Institute of Scientific and Technical Information of China (English)

    LV Jianglin; HUANG Guang

    2015-01-01

    Based on the theoretical analysis,this paper applies the entropy method to establish a comprehensive index system for the evaluation of the overall level of risk control and comprehensive efficiency of the supervision of China's commercial banks.Considering the trinity-characteristics of bank supervision system consisting of the People's Bank of China(PBC),the CBRC and the financial offices of local governments,the following conclusions have been drawn:the amount of penalties on banking illegal transactions is not correlated with the supervision efficiency of China's commercial banks;the capital adequacy ratio,the loan to deposit ratio,the percentage point of the non-performing loan rate of urban commercial banks higher than that of the national joint-stock banks are negatively correlated with the supervision efficiency of China 's commercial banks;the total asset variation of the PBC and the different loan balance in local and foreign currency of the banks are positively correlated with the supervision efficiency of China's commercial banks,but the effect is minor.Therefore,China should give the capital adequacy ratio a full play in the bank supervision,accelerate the construction of supervision information system and improve the supervision function of the local governments.

  6. Polynomial fuzzy model-based control systems stability analysis and control synthesis using membership function dependent techniques

    CERN Document Server

    Lam, Hak-Keung

    2016-01-01

    This book presents recent research on the stability analysis of polynomial-fuzzy-model-based control systems where the concept of partially/imperfectly matched premises and membership-function dependent analysis are considered. The membership-function-dependent analysis offers a new research direction for fuzzy-model-based control systems by taking into account the characteristic and information of the membership functions in the stability analysis. The book presents on a research level the most recent and advanced research results, promotes the research of polynomial-fuzzy-model-based control systems, and provides theoretical support and point a research direction to postgraduate students and fellow researchers. Each chapter provides numerical examples to verify the analysis results, demonstrate the effectiveness of the proposed polynomial fuzzy control schemes, and explain the design procedure. The book is comprehensively written enclosing detailed derivation steps and mathematical derivations also for read...

  7. Supervision Duty of School Principals

    Directory of Open Access Journals (Sweden)

    Kürşat YILMAZ

    2009-04-01

    Full Text Available Supervision by school administrators is becoming more and more important. The change in the roles ofschool administrators has a great effect on that increase. At present, school administrators are consideredmore than as technical directors, but as instructional leaders. This increased the importance of schooladministrators’ expected supervision acts. In this respect, the aim of this study is to make a conceptualanalysis about school administrators’ supervision duties. For this reason, a literature review related withsupervision and contemporary supervision approaches was done, and the official documents concerningsupervision were examined. As a result, it can be said that school administrators’ supervision duties havebecome very important. And these duties must certainly be carried out by school administrators.

  8. Nursing supervision for care comprehensiveness

    Directory of Open Access Journals (Sweden)

    Lucieli Dias Pedreschi Chaves

    Full Text Available ABSTRACT Objective: To reflect on nursing supervision as a management tool for care comprehensiveness by nurses, considering its potential and limits in the current scenario. Method: A reflective study based on discourse about nursing supervision, presenting theoretical and practical concepts and approaches. Results: Limits on the exercise of supervision are related to the organization of healthcare services based on the functional and clinical model of care, in addition to possible gaps in the nurse training process and work overload. Regarding the potential, researchers emphasize that supervision is a tool for coordinating care and management actions, which may favor care comprehensiveness, and stimulate positive attitudes toward cooperation and contribution within teams, co-responsibility, and educational development at work. Final considerations: Nursing supervision may help enhance care comprehensiveness by implying continuous reflection on including the dynamics of the healthcare work process and user needs in care networks.

  9. Sliding Mode Controller and Lyapunov Redesign Controller to Improve Microgrid Stability:A Comparative Analysis with CPL Power Variation

    OpenAIRE

    Hossain, Eklas; Perez, Ron; Padmanaban, Sanjeevikumar; Mihet-Popa, Lucian; Blaabjerg, Frede; Ramachandaramurthy, Vigna K.

    2017-01-01

    To mitigate the microgrid instability despite the presence of dense Constant Power Load (CPL) loads in the system, a number of compensation techniques have already been gone through extensive research, proposed, and implemented around the world. In this paper, a storage based load side compensation technique is used to enhance stability of microgrids. Besides adopting this technique here, Sliding Mode Controller (SMC) and Lyapunov Redesign Controller (LRC), two of the most prominent nonlinear...

  10. Postural stability in patients with knee osteoarthritis: comparison with controls and evaluation of relationships between postural stability scores and International Classification of Functioning, Disability and Health components.

    Science.gov (United States)

    Hsieh, Ru-Lan; Lee, Wen-Chung; Lo, Min-Tzu; Liao, Wei-Cheng

    2013-02-01

    To assess the differences in postural stability between patients with knee osteoarthritis and controls without knee osteoarthritis, and to evaluate possible relations between postural stability scores and International Classification of Functioning, Disability and Health (ICF) components. An age-matched, case-controlled trial with a cross-sectional design. A teaching hospital. Patients with knee osteoarthritis (n=73) and age-matched controls (n=60). Data on patients' postural stability and additional health-related variables were collected using various instruments. These included the Hospital Anxiety and Depression Scale, the Multidimensional Fatigue Inventory, the World Health Organization Quality of Life Brief Version, the physical function test (chair-rising time), the Chinese version of the Western Ontario and McMaster Universities Osteoarthritis Index, the Chinese version of the Knee Injury and Osteoarthritis Outcome Score, and the Biodex Stability System. A comparison of postural stability in patients with knee osteoarthritis versus that of controls was performed. The relation between postural stability scores for patients with knee osteoarthritis and ICF components was evaluated. Pearson correlation tests were used to determine the variables that correlated with postural stability among these patients. Patients with knee osteoarthritis displayed lower overall postural stability than controls (scores of 0.7 vs. 0.5, P=.006) and scored lower on the environmental domain of the World Health Organization Quality of Life Brief Version (62.2 vs 66.8, P=.014). For patients with knee osteoarthritis, postural stability was weakly associated with the ICF components of body functions and structures, including pain (r=.33-.34, P=.004), physical fatigue (r=.28, P=.016), and reduced motivation (r=.30, P=.011). Weak to moderate associations between postural stability and the ICF components of activities and participation were found; the relevant ICF variables included

  11. Stability Enhancement of Multi machine AC Systems by Synchronverter HVDC control

    Directory of Open Access Journals (Sweden)

    Raouia Aouini

    2016-06-01

    Full Text Available This paper investigates the impact of the Synchronverter based HVDC control on power system stability. The study considers multi machine power systems, with realistic parameters. A specific tuning method of the parameters of the regulators is used. The proposed control scheme is based on the sensitivity of the poles of the HVDC neighbor zone to the control parameters, and next, on their placement using residues. The transient stability of the HVDC neighbor zone is a priori taken into account at the design stage. The new tuning method is evaluated in comparison with the standard vector control via simulation tests. Extensive tests are performed using Matlab/Simulink implementation of the IEEE 9 bus/3 machines test system. The results prove the superiority of the proposed control to the classic vector control. The synchronverter control allows to improve not only the local performances of the HVDC link, but also the overall transient stability of the AC zone in which the HVDC is inserted. (where

  12. Temporal stability and transferability of models of willingness to pay for flood control and wetland conservation

    NARCIS (Netherlands)

    Brouwer, R.; Bateman, I.J.

    2005-01-01

    This study investigates the temporal stability and transferability of dichotomous choice willingness to pay responses and their determinants from two large-scale contingent valuation surveys in the area of flood control and wetland conservation. The study considers a time period between surveys

  13. Study on transient stability of wind turbine with induction generator based on variable pitch control strategy

    DEFF Research Database (Denmark)

    Zhao, B.; Li, H.; Han, L.

    2011-01-01

    In order to enhance and improve the transient stability of a grid-connected wind turbine generator system under the power grid fault, based on typical pitch control strategy of wind turbine, considering the wind turbine system oscillation caused by the drive-train shaft flexibility, Based on Matl...

  14. IQC-based robust stability analysis for LPV control of doubly-fed induction generators

    NARCIS (Netherlands)

    Tien, H. N.; Scherer, C. W.; Scherpen, J. M. A.

    2008-01-01

    Parameters of electrical machines are usually varying with time in a smooth way due to changing operating conditions, such as variations in the machine temperature and/or the magnetic saturation. This paper is concerned with robust stability analysis of controlled Doubly-Fed Induction Generators

  15. Asymptotic Stabilization of Non-holonomic Port-controlled Hamiltonian Systems

    DEFF Research Database (Denmark)

    Sørensen, Mathias Jesper; Bendtsen, Jan Dimon; Andersen, Palle

    2004-01-01

    A novel method for asymptotic stabilization of a class of non-holonomic systems is presented. The method is based on the port-controlled Hamiltonian description of electro-mechanical systems. The general system is augmented with so-called kinematic inputs, thus representing a special class of mob...

  16. Stability and control of Lur'e-type measure differential inclusions

    NARCIS (Netherlands)

    Wouw, van de N.; Leine, R.I.; Leonov, G.; Nijmeijer, H.; Pogromsky, A.; Fradkov, A.

    2010-01-01

    In this paper we present results on, firstly, the stability analysis for perturbed Lur'e-type measure differential inclusions and, secondly, the tracking control problem for this class of systems. The framework of measure differential inclusions allows us to describe systems with discontinuities in

  17. High stability vector-based direct power control for DFIG-based wind turbine

    DEFF Research Database (Denmark)

    Zhu, Rongwu; Chen, Zhe; Wu, Xiaojie

    2015-01-01

    This paper proposes an improved vector-based direct power control (DPC) strategy for the doubly-fed induction generator (DFIG)-based wind energy conversion system. Based on the small signal model, the proposed DPC improves the stability of the DFIG, and avoids the DFIG operating in the marginal...

  18. Recent Advances in Heliogyro Solar Sail Structural Dynamics, Stability, and Control Research

    Science.gov (United States)

    Wilkie, W. Keats; Warren, Jerry E.; Horta, Lucas G.; Lyle, Karen H.; Juang, Jer-Nan; Gibbs, S. Chad; Dowell, Earl H.; Guerrant, Daniel V.; Lawrence, Dale

    2015-01-01

    Results from recent NASA sponsored research on the structural dynamics, stability, and control characteristics of heliogyro solar sails are summarized. Specific areas under investigation include coupled nonlinear finite element analysis of heliogyro membrane blade with solar radiation pressure effects, system identification of spinning membrane structures, and solarelastic stability analysis of heliogyro solar sails, including stability during blade deployment. Recent results from terrestrial 1-g blade dynamics and control experiments on "rope ladder" membrane blade analogs, and small-scale in vacuo system identification experiments with hanging and spinning high-aspect ratio membranes will also be presented. A low-cost, rideshare payload heliogyro technology demonstration mission concept is used as a mission context for these heliogyro structural dynamics and solarelasticity investigations, and is also described. Blade torsional dynamic response and control are also shown to be significantly improved through the use of edge stiffening structural features or inclusion of modest tip masses to increase centrifugal stiffening of the blade structure. An output-only system identification procedure suitable for on-orbit blade dynamics investigations is also developed and validated using ground tests of spinning sub-scale heliogyro blade models. Overall, analytical and experimental investigations to date indicate no intractable stability or control issues for the heliogyro solar sail concept.

  19. Stability analysis of DC microgrids with constant power load under distributed control methods

    DEFF Research Database (Denmark)

    Liu, Zhangjie; Su, Mei; Sun, Yao

    2018-01-01

    of distributed controller is investigated. The small-signal model is established to predict the system qualitative behavior around equilibrium. The stability conditions of the system with time delay are derived based on the equivalent linearized model. Additionally, eigenvalue analysis based on inertia theorem...

  20. A Control Strategy for Flywheel Energy Storage System for Frequency Stability Improvement in Islanded Microgrid

    Directory of Open Access Journals (Sweden)

    A. A. Khodadoost Arani

    2017-03-01

    Full Text Available The Micro-Grid (MG stability is a significant issue that must be maintained in all operational modes. Usually, two control strategies can be applied to MG; V/f control and PQ control strategies. MGs with V/f control strategy should have some Distributed Generators (DGs which have fast responses versus load changes. The Flywheel Energy Storage System (FESS has this characteristic. The FESS, which converts the mechanical energy to electrical form, can generate electrical power or absorb the additional power in power systems or MGs. In this paper, the FESS structure modeled in detail and two control strategies (V/f and PQ control are applied for this application. In addition, in order to improve the MG frequency and voltage stability, two complementary controllers are proposed for the V/f control strategy; conventional PI and Fuzzy Controllers. A typical low voltage network, including FESS is simulated for four distinct scenarios in the MATLAB/ Simulink environment. It is shown that fuzzy controller has better performance than conventional PI controller in islanded microgrid.

  1. Thermal stability analysis and auxiliary power feedback control for the tokamak engineering test breeder (TETB-II)

    International Nuclear Information System (INIS)

    Sheng Guangzhao

    1993-01-01

    The thermal stability of TETB-II is analyzed using different methods, viz., POPCON, linear stability analysis and the time evolution calculation of plasma parameters. A thermal instability of the TETB-II is predicted. Auxiliary power feedback control for thermal stability appears feasible and efficient

  2. Controlled high-fidelity navigation in the charge stability diagram of a double quantum dot

    International Nuclear Information System (INIS)

    Coden, Diego S Acosta; Romero, Rodolfo H; Räsänen, Esa

    2015-01-01

    We propose an efficient control protocol for charge transfer in a double quantum dot. We consider numerically a two-dimensional model system, where the quantum dots are subjected to time-dependent electric fields corresponding to experimental gate voltages. Our protocol enables navigation in the charge stability diagram from a state to another through controllable variation of the fields. We show that the well-known adiabatic Landau–Zener transition—when supplemented with a time-dependent field tailored with optimal control theory—can remarkably improve the transition speed. The results also lead to a simple control scheme obtained from the experimental charge stability diagram that requires only a single parameter. Eventually, we can achieve the ultrafast performance of the composite pulse protocol that allows the system to be driven at the quantum speed limit. (paper)

  3. Axial stability of VVER-1000 reactor with control with minimum standard deviation

    International Nuclear Information System (INIS)

    Afanas'ev, A.M.; Torlin, B.Z.

    1980-01-01

    Results are given of investigations on the stability of a reactor which has, in addition to an automatic controller, a height distribution regulator (HDR) based on an auxiliary control rod (CR) or a special shortened absorption rod (SAR). The HDR was controlled by using either a special ionization chamber (IC), generating an imbalance signal which sets the CR in motion, or two ionization chambers whose difference signal causes a displacement of the SAR. Since data from numerous pickups can be used to control the height field of the VVER-1000, it is of interest to analyze how this would affect the stability of the reactor. The analysis was carried out with the improved IRINA programs. 11 refs

  4. Rapid feedback control and stabilization of an optical tweezers with a budget microcontroller

    International Nuclear Information System (INIS)

    Nino, Daniel; Wang, Haowei; N Milstein, Joshua

    2014-01-01

    Laboratories ranging the scientific disciplines employ feedback control to regulate variables within their experiments, from the flow of liquids within a microfluidic device to the temperature within a cell incubator. We have built an inexpensive, yet fast and rapidly deployed, feedback control system that is straightforward and flexible to implement from a commercially available Arduino Due microcontroller. This is in comparison with the complex, time-consuming and often expensive electronics that are commonly implemented. As an example of its utility, we apply our feedback controller to the task of stabilizing the main trapping laser of an optical tweezers. The feedback controller, which is inexpensive yet fast and rapidly deployed, was implemented from hacking an open source Arduino Due microcontroller. Our microcontroller based feedback system can stabilize the laser intensity to a few tenths of a per cent at 200 kHz, which is an order of magnitude better than the laser's base specifications, illustrating the utility of these devices. (paper)

  5. Improvement of the directional stability of passenger car trailer couplings with actively controlled steering

    Science.gov (United States)

    Desens, Jens

    The stabilization of pendulum oscillations of passenger car trailer couplings, using active steering, was examined. A linear model of the couplings was presented. Each axle was provided with a controller. The controllers were optimized, with regard to necessary sensors, in order to minimize costs. The rear and the front axles were provided with a control unit in order to compute the potential prevailing in the active steering of several axles. It was shown that the passenger car rear axle was the most suitable for coupling stabilization. The experiment was simulated, using a complex coupling model. The developed controller allowed the passenger car trailer to be driven at a speed higher than 150 km per hour.

  6. Rapid feedback control and stabilization of an optical tweezers with a budget microcontroller

    Energy Technology Data Exchange (ETDEWEB)

    Nino, Daniel; Wang, Haowei; N Milstein, Joshua, E-mail: josh.milstein@utoronto.ca [Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, ON L5L 1C6 (Canada)

    2014-09-01

    Laboratories ranging the scientific disciplines employ feedback control to regulate variables within their experiments, from the flow of liquids within a microfluidic device to the temperature within a cell incubator. We have built an inexpensive, yet fast and rapidly deployed, feedback control system that is straightforward and flexible to implement from a commercially available Arduino Due microcontroller. This is in comparison with the complex, time-consuming and often expensive electronics that are commonly implemented. As an example of its utility, we apply our feedback controller to the task of stabilizing the main trapping laser of an optical tweezers. The feedback controller, which is inexpensive yet fast and rapidly deployed, was implemented from hacking an open source Arduino Due microcontroller. Our microcontroller based feedback system can stabilize the laser intensity to a few tenths of a per cent at 200 kHz, which is an order of magnitude better than the laser's base specifications, illustrating the utility of these devices. (paper)

  7. Stability and Control of Large-Scale Dynamical Systems A Vector Dissipative Systems Approach

    CERN Document Server

    Haddad, Wassim M

    2011-01-01

    Modern complex large-scale dynamical systems exist in virtually every aspect of science and engineering, and are associated with a wide variety of physical, technological, environmental, and social phenomena, including aerospace, power, communications, and network systems, to name just a few. This book develops a general stability analysis and control design framework for nonlinear large-scale interconnected dynamical systems, and presents the most complete treatment on vector Lyapunov function methods, vector dissipativity theory, and decentralized control architectures. Large-scale dynami

  8. Offshore Wind Farms and HVDC Grids Modeling as a Feedback Control System for Stability Analysis

    OpenAIRE

    Bidadfar, Ali; Saborío-Romano, Oscar; Altin, Müfit; Göksu, Ömer; Cutululis, Nicolaos Antonio; Sørensen, Poul Ejnar

    2017-01-01

    The low impedance characteristics of DC transmission lines cause the voltage source converter (VSC) in HVDC networks to become electrically closer together and increase the risk of severe interactions between the converters. Such interactions, in turn, intensify the implementation of the grid control schemes and may lead the entire system to instability. Assessing the stability and adopting complex coordinated control schemes in an HVDC grid and wind farm turbines are challenging and require ...

  9. A Good Turn Deserves Another: Political Stability, Corruption and Corruption-Control

    OpenAIRE

    Simplice A Asongu

    2015-01-01

    We build on existing literature and contemporary challenges to African development to assess the role of political stability in fighting corruption and boosting corruption-control in 53 African countries for the period 1996-2010. We postulate that on the one hand, an atmosphere of political instability should increase the confidence of impunity owing to less corruption-control. On the other hand, in the absence such impunity from corruption, political instability further fuels corruption. Our...

  10. Social construction : discursive perspective towards supervision

    OpenAIRE

    Naujanienė, Rasa

    2010-01-01

    The aim of publication is to discuss the development of supervision theory in relation with social and social work theory and practice. Main focus in the analysis is done to social constructionist ideas and its’ relevance to supervision practice. The development of supervision is related with supervision practice. Starting in 19th century supervision from giving practical advices supervision came to 21st century as dialog based on critical and philosophical reflection. Different theory and pr...

  11. Physical activity and return to work after fast-track total hip replacement with or without supervised rehabilitation. Results from a randomized controlled trial

    DEFF Research Database (Denmark)

    Mikkelsen, Lone Ramer; Mechlenburg, Inger; Søballe, Kjeld

    rehabilitation affects the activity level as well as return to work after THR. Purpose/Aim of Study To investigate whether supervised progressive resistance training during the first 10 weeks after THR affects the change in physical activity level from baseline to 6 months after THR and the timing of return...... activity was measured in metabolic equivalents (MET) by Physical Activity Scale (PAS) and days until return to work for the working population. Findings / Results Follow up was completed by 62 patients (85%). Changes in PAS scores from baseline to 6 months follow up were, mean [95% CI]: IG: 6.32 [3...... their self-reported physical activity level more than patients performing home-based exercise only, during 6 months after THR however, the difference was eliminated at 1 year follow up. No significant difference was found concerning return to work....

  12. Controlling chaos in permanent magnet synchronous motor based on finite-time stability theory

    International Nuclear Information System (INIS)

    Du-Qu, Wei; Bo, Zhang

    2009-01-01

    This paper reports that the performance of permanent magnet synchronous motor (PMSM) degrades due to chaos when its systemic parameters fall into a certain area. To control the undesirable chaos in PMSM, a nonlinear controller, which is simple and easy to be constructed, is presented to achieve finite-time chaos control based on the finite-time stability theory. Computer simulation results show that the proposed controller is very effective. The obtained results may help to maintain the industrial servo driven system's security operation. (general)

  13. Quadratic Stabilization of LPV System by an LTI Controller Based on ILMI Algorithm

    Directory of Open Access Journals (Sweden)

    Wei Xie

    2007-01-01

    Full Text Available A linear time-invariant (LTI output feedback controller is designed for a linear parameter-varying (LPV control system to achieve quadratic stability. The LPV system includes immeasurable dependent parameters that are assumed to vary in a polytopic space. To solve this control problem, a heuristic algorithm is proposed in the form of an iterative linear matrix inequality (ILMI formulation. Furthermore, an effective method of setting an initial value of the ILMI algorithm is also proposed to increase the probability of getting an admissible solution for the controller design problem.

  14. Stability Analysis of a Voltage-Based Controller for Robot Manipulators

    Directory of Open Access Journals (Sweden)

    Jorge Orrante-Sakanassi

    2013-01-01

    Full Text Available A voltage-based control scheme for robot manipulators has been presented in recent literature, where feedback linearization is applied in the electrical equations of the DC motors in order to cancel the electrical current terms. However, in this paper we show that this control technique generates a system of the form Ex = Ax + Bu, where E is a singular matrix, that is to say, a generalized state-space system or singular system. This paper introduces a formal stability analysis of the respective system by considering the state-space equation as a singular system. Furthermore, in order to avoid the singularity of the closed-loop system, modified voltage-based control schemes are proposed, whose Lyapunov stability analyses conclude semiglobal asymptotic stability for the set-point control case and uniform boundedness of the solutions and semiglobal convergence of the position, as well as velocity errors for the tracking control case. The proposed control systems are simulated for the tracking and set-point cases using the CICESE Pelican robot driven by DC motors.

  15. Nonlinear Synergetic Governor Controllers for Steam Turbine Generators to Enhance Power System Stability

    Directory of Open Access Journals (Sweden)

    Xingbao Ju

    2017-07-01

    Full Text Available This paper proposes a decentralized nonlinear synergetic governor controller (NSGC for turbine generators to enhance power system stability by using synergetic control theory and the feedback linearization technique. The precise feedback linearization model of a turbine-generator with a steam valve control is obtained, at first, by using a feedback linearization technique. Then based on this model, a manifold is defined as a linear combination of the deviation of the rotor angle, speed deviation, and speed derivative. The control law of the proposed NSGC is deduced and the stability condition of the whole closed-loop system is subsequently analyzed. According to the requirement of the primary frequency regulation, an additional proportional integral (PI controller is designed to dynamically track the steady-state value of the rotor angle. Case studies are undertaken based on a single-machine infinite-bus system and the New England system, respectively. Simulation results show that the proposed NSGC can suppress the power oscillations and improve transient stability more effectively in comparison with the conventional proportional-integral-derivative (PID governor controller. Moreover, the proposed NSGC is robust to the variations of the system operating conditions.

  16. WIND TUNNEL EVALUATION FOR CONTROL TRANSITION FROM ELEVATOR TO STABILATOR OF SMALL UAV

    Directory of Open Access Journals (Sweden)

    ZULHILMY SAHWEE

    2017-06-01

    Full Text Available Faulty control surface actuator in a small Unmanned Aerial Vehicles (sUAV could be overcome with a few techniques. Redundant actuators, analytical redundancy or combination of both are normally used as fault accommodation techniques. In this paper, the accommodation technique of faulty elevator actuator is presented. This technique uses a standby control surface as temporary control reallocation. Wind tunnel measurement facility is set up for the experimental validation and it is compared with FoilSim software. Flat plate airfoil which was used as horizontal stabilizer, is simulated using numerical model and it is validated using the wind tunnel test. Then, a flat airfoil is designed to be used as stabilator for the recovery of faulty elevator actuator. Results show the different deflection angle is needed when transferring from one control surface to another. From the analysis, the proposed method could be implemented without affecting the pitch stability during control surface transition. The alternate control surface accommodation technique proves to be promising for higher reliability sUAV in the case of a faulty on-board actuator.

  17. Stability Analysis of a Type of Takagi-Sugeno PI Fuzzy Control Systems Using Circle Criterion

    Directory of Open Access Journals (Sweden)

    Kairui Cao

    2011-04-01

    Full Text Available A type of Takagi-Sugeno (T-S Proportional-Integral (PI fuzzy controllers is studied. The T-S PI fuzzy controller is formed by a T-S Proportional-Derivative (PD fuzzy controller connected with an integrator. In this particular structure, the T-S PD fuzzy controller is a weighted sum of some linear PD sub-controllers. The mathematical properties of our T-S PI fuzzy controller are also investigated. Based on these properties, the global asymptotic stability of the fuzzy control systems, in which the T-S PI fuzzy controllers are employed, are analyzed by using the well-known circle criterion. A sufficient condition with an elegant graphical interpretation in the frequency domain is further derived to guarantee the global asymptotic stability of the above fuzzy control systems. Finally, two numerical examples are provided to demonstrate how to deploy this method in analyzing the T-S PI fuzzy control systems in the frequency domain with the aid of some simple graphs.

  18. Stability Constrained Efficiency Optimization for Droop Controlled DC-DC Conversion System

    DEFF Research Database (Denmark)

    Meng, Lexuan; Dragicevic, Tomislav; Guerrero, Josep M.

    2013-01-01

    implementing tertiary regulation. Moreover, system dynamic is affected when shifting VRs. Therefore, the stability is considered in optimization by constraining the eigenvalues arising from dynamic state space model of the system. Genetic algorithm is used in searching for global efficiency optimum while....... As the efficiency of each converter changes with output power, virtual resistances (VRs) are set as decision variables for adjusting power sharing proportion among converters. It is noteworthy that apart from restoring the voltage deviation, secondary control plays an important role to stabilize dc bus voltage when...

  19. Classical linear-control analysis applied to business-cycle dynamics and stability

    Science.gov (United States)

    Wingrove, R. C.

    1983-01-01

    Linear control analysis is applied as an aid in understanding the fluctuations of business cycles in the past, and to examine monetary policies that might improve stabilization. The analysis shows how different policies change the frequency and damping of the economic system dynamics, and how they modify the amplitude of the fluctuations that are caused by random disturbances. Examples are used to show how policy feedbacks and policy lags can be incorporated, and how different monetary strategies for stabilization can be analytically compared. Representative numerical results are used to illustrate the main points.

  20. Exponential stabilization and synchronization for fuzzy model of memristive neural networks by periodically intermittent control.

    Science.gov (United States)

    Yang, Shiju; Li, Chuandong; Huang, Tingwen

    2016-03-01

    The problem of exponential stabilization and synchronization for fuzzy model of memristive neural networks (MNNs) is investigated by using periodically intermittent control in this paper. Based on the knowledge of memristor and recurrent neural network, the model of MNNs is formulated. Some novel and useful stabilization criteria and synchronization conditions are then derived by using the Lyapunov functional and differential inequality techniques. It is worth noting that the methods used in this paper are also applied to fuzzy model for complex networks and general neural networks. Numerical simulations are also provided to verify the effectiveness of theoretical results. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. The effectiveness of Technology-assisted Cascade Training and Supervision of community health workers in delivering the Thinking Healthy Program for perinatal depression in a post-conflict area of Pakistan - study protocol for a randomized controlled trial.

    Science.gov (United States)

    Zafar, Shamsa; Sikander, Siham; Hamdani, Syed Usman; Atif, Najia; Akhtar, Parveen; Nazir, Huma; Maselko, Joanna; Rahman, Atif

    2016-04-06

    Rates of perinatal depression in low and middle income countries are reported to be very high. Perinatal depression not only has profound impact on women's health, disability and functioning, it is associated with poor child health outcomes such as pre-term birth, under-nutrition and stunting, which ultimately have an adverse trans-generational impact. There is strong evidence in the medical literature that perinatal depression can be effectively managed with psychological treatments delivered by non-specialists. Our previous research in Pakistan led to the development of a successful perinatal depression intervention, the Thinking Healthy Program (THP). The THP is a psychological treatment delivered by community health workers. The burden of perinatal depression can be reduced through scale-up of this proven intervention; however, training of health workers at scale is a major barrier. To enhance access to such interventions there is a need to look at technological solutions to training and supervision. This is a non-inferiority, single-blinded randomized controlled trial. Eighty community health workers called Lady Health Workers (LHWs) working in a post-conflict rural area in Pakistan (Swat) will be recruited through the LHW program. LHWs will be randomly allocated to Technology-assisted Cascade Training and Supervision (TACTS) or to specialist-delivered training (40 in each group). The TACTS group will receive training in THP through LHW supervisors using a tablet-based training package, whereas the comparison group will receive training directly from mental health specialists. Our hypothesis is that both groups will achieve equal competence. Primary outcome measure will be competence of health workers at delivering THP using a modified ENhancing Assessment of Common Therapeutic factors (ENACT) rating scale immediately post training and after 3 months of supervision. Independent assessors will be blinded to the LHW allocation status. Women living in post

  2. Stabilizing periodic orbits of chaotic systems using fuzzy adaptive sliding mode control

    Energy Technology Data Exchange (ETDEWEB)

    Layeghi, Hamed [Department of Mechanical Engineering, Sharif University of Technology, Center of Excellence in Design, Robotics and Automation, Azadi Avenue, Postal Code 11365-9567 Tehran (Iran, Islamic Republic of)], E-mail: layeghi@mech.sharif.edu; Arjmand, Mehdi Tabe [Department of Mechanical Engineering, Sharif University of Technology, Center of Excellence in Design, Robotics and Automation, Azadi Avenue, Postal Code 11365-9567 Tehran (Iran, Islamic Republic of)], E-mail: arjmand@mech.sharif.edu; Salarieh, Hassan [Department of Mechanical Engineering, Sharif University of Technology, Center of Excellence in Design, Robotics and Automation, Azadi Avenue, Postal Code 11365-9567 Tehran (Iran, Islamic Republic of)], E-mail: salarieh@mech.sharif.edu; Alasty, Aria [Department of Mechanical Engineering, Sharif University of Technology, Center of Excellence in Design, Robotics and Automation, Azadi Avenue, Postal Code 11365-9567 Tehran (Iran, Islamic Republic of)], E-mail: aalasti@sharif.edu

    2008-08-15

    In this paper by using a combination of fuzzy identification and the sliding mode control a fuzzy adaptive sliding mode scheme is designed to stabilize the unstable periodic orbits of chaotic systems. The chaotic system is assumed to have an affine form x{sup (n)} = f(X) + g(X)u where f and g are unknown functions. Using only the input-output data obtained from the underlying dynamical system, two fuzzy systems are constructed for identification of f and g. Two distinct methods are utilized for fuzzy modeling, the least squares and the gradient descent techniques. Based on the estimated fuzzy models, an adaptive controller, which works through the sliding mode control, is designed to make the system track the desired unstable periodic orbits. The stability analysis of the overall closed loop system is presented in the paper and the effectiveness of the proposed adaptive scheme is numerically investigated. As a case of study, modified Duffing system is selected for applying the proposed method to stabilize its 2{pi} and 4{pi} periodic orbits. Simulation results show the high performance of the method for stabilizing the unstable periodic orbits of unknown chaotic systems.

  3. Online supervision at the university

    DEFF Research Database (Denmark)

    Bengtsen, Søren Smedegaard; Jensen, Gry Sandholm

    2015-01-01

    supervision proves unhelpful when trying to understand how online supervision and feedback is a pedagogical phenomenon in its own right, and irreducible to the face-to-face context. Secondly we show that not enough attention has been given to the way different digital tools and platforms influence...... pedagogy we forge a new concept of “format supervision” that enables supervisors to understand and reflect their supervision practice, not as caught in the physical-virtual divide, but as a choice between face-to-face and online formats that each conditions the supervisory dialogue in their own particular...

  4. Local supervision of solariums

    International Nuclear Information System (INIS)

    2004-01-01

    In Norway, new regulations on radiation protection and application of radiation came into force on the first of January 2004. Local authorities may now perform the supervision of solariums. There are over 500 solar studios in Norway, with over 5000 solariums accessible to the public. An unknown number of solariums are in private homes, on workplaces, and in hotels and fitness studios. Norway currently has the highest frequency of skin cancer in Europe. The frequency of mole cancer has increased sixfold during the last 30 years, and 200 people die each year of this type of cancer. The Nordic cancer registers estimate that 95 per cent of the skin cancer incidences would have been avoided by limiting sunbathing. It is unknown how many cases are due to the use of solariums. But several studies indicate increased risk of mole cancer caused by solariums. It was found in previous inspection of 130 solariums that only 30 per cent had correct tubes and lamps. Only one solarium satisfied all the requirements of the regulations. But this has since improved. With the new regulations, all solarium businesses offering cosmetic solariums for sale, renting out or use have an obligation to submit reports to the Radiation Protection Authority

  5. Design of a Stability Augmentation System for an Unmanned Helicopter Based on Adaptive Control Techniques

    Directory of Open Access Journals (Sweden)

    Shouzhao Sheng

    2015-09-01

    Full Text Available The task of control of unmanned helicopters is rather complicated in the presence of parametric uncertainties and measurement noises. This paper presents an adaptive model feedback control algorithm for an unmanned helicopter stability augmentation system. The proposed algorithm can achieve a guaranteed model reference tracking performance and speed up the convergence rates of adjustable parameters, even when the plant parameters vary rapidly. Moreover, the model feedback strategy in the algorithm further contributes to the improvement in the control quality of the stability augmentation system in the case of low signal to noise ratios, mainly because the model feedback path is noise free. The effectiveness and superiority of the proposed algorithm are demonstrated through a series of tests.

  6. Implementation of model predictive control for resistive wall mode stabilization on EXTRAP T2R

    Science.gov (United States)

    Setiadi, A. C.; Brunsell, P. R.; Frassinetti, L.

    2015-10-01

    A model predictive control (MPC) method for stabilization of the resistive wall mode (RWM) in the EXTRAP T2R reversed-field pinch is presented. The system identification technique is used to obtain a linearized empirical model of EXTRAP T2R. MPC employs the model for prediction and computes optimal control inputs that satisfy performance criterion. The use of a linearized form of the model allows for compact formulation of MPC, implemented on a millisecond timescale, that can be used for real-time control. The design allows the user to arbitrarily suppress any selected Fourier mode. The experimental results from EXTRAP T2R show that the designed and implemented MPC successfully stabilizes the RWM.

  7. Implementation of model predictive control for resistive wall mode stabilization on EXTRAP T2R

    International Nuclear Information System (INIS)

    Setiadi, A C; Brunsell, P R; Frassinetti, L

    2015-01-01

    A model predictive control (MPC) method for stabilization of the resistive wall mode (RWM) in the EXTRAP T2R reversed-field pinch is presented. The system identification technique is used to obtain a linearized empirical model of EXTRAP T2R. MPC employs the model for prediction and computes optimal control inputs that satisfy performance criterion. The use of a linearized form of the model allows for compact formulation of MPC, implemented on a millisecond timescale, that can be used for real-time control. The design allows the user to arbitrarily suppress any selected Fourier mode. The experimental results from EXTRAP T2R show that the designed and implemented MPC successfully stabilizes the RWM. (paper)

  8. Inverse Doppler shift and control field as coherence generators for the stability in superluminal light

    Science.gov (United States)

    Ghafoor, Fazal; Bacha, Bakht Amin; Khan, Salman

    2015-05-01

    A gain-based four-level atomic medium for the stability in superluminal light propagation using control field and inverse Doppler shift as coherence generators is studied. In regimes of weak and strong control field, a broadband and multiple controllable transparency windows are, respectively, identified with significantly enhanced group indices. The observed Doppler effect for the class of high atomic velocity of the medium is counterintuitive in comparison to the effect of the class of low atomic velocity. The intensity of each of the two pump fields is kept less than the optimum limit reported in [M. D. Stenner and D. J. Gauthier, Phys. Rev. A 67, 063801 (2003), 10.1103/PhysRevA.67.063801] for stability in the superluminal light pulse. Consequently, superluminal stable domains with the generated coherence are explored.

  9. Stabilization of Continuous-Time Random Switching Systems via a Fault-Tolerant Controller

    Directory of Open Access Journals (Sweden)

    Guoliang Wang

    2017-01-01

    Full Text Available This paper focuses on the stabilization problem of continuous-time random switching systems via exploiting a fault-tolerant controller, where the dwell time of each subsystem consists of a fixed part and random part. It is known from the traditional design methods that the computational complexity of LMIs related to the quantity of fault combination is very large; particularly system dimension or amount of subsystems is large. In order to reduce the number of the used fault combinations, new sufficient LMI conditions for designing such a controller are established by a robust approach, which are fault-free and could be solved directly. Moreover, the fault-tolerant stabilization realized by a mode-independent controller is considered and suitably applied to a practical case without mode information. Finally, a numerical example is used to demonstrate the effectiveness and superiority of the proposed methods.

  10. Solving ill-posed control problems by stabilized finite element methods: an alternative to Tikhonov regularization

    Science.gov (United States)

    Burman, Erik; Hansbo, Peter; Larson, Mats G.

    2018-03-01

    Tikhonov regularization is one of the most commonly used methods for the regularization of ill-posed problems. In the setting of finite element solutions of elliptic partial differential control problems, Tikhonov regularization amounts to adding suitably weighted least squares terms of the control variable, or derivatives thereof, to the Lagrangian determining the optimality system. In this note we show that the stabilization methods for discretely ill-posed problems developed in the setting of convection-dominated convection-diffusion problems, can be highly suitable for stabilizing optimal control problems, and that Tikhonov regularization will lead to less accurate discrete solutions. We consider some inverse problems for Poisson’s equation as an illustration and derive new error estimates both for the reconstruction of the solution from the measured data and reconstruction of the source term from the measured data. These estimates include both the effect of the discretization error and error in the measurements.

  11. Virtual velocity loop based on MEMS accelerometers for optical stabilization control system

    Science.gov (United States)

    Ren, Wei; Deng, Chao; Mao, Yao; Ren, Ge

    2017-08-01

    In the optical stabilization control system (OSCS) control system based on a charge-coupled device (CCD), stabilization performance of the line-of-sight is severely limited by the mechanical resonance and the low sampling rate of the CCD. An approach to improve the stabilization performance of the OSCS control system with load restriction based on three loops, including an acceleration loop, a virtual velocity loop, and a position loop, by using MEMS accelerometers and a CCD is proposed. The velocity signal is obtained by accelerators instead of gyro sensors. Its advantages are low power, low cost, small size, and wide measuring range. A detailed analysis is provided to show how to design the virtual velocity loop and correct virtual velocity loop drift. Experimental results show that the proposed multiloop feedback control method with virtual velocity loop in which the disturbance suppression performance is better than that of the dual loop control with only an acceleration loop and a position loop at low frequency.

  12. Design of stability-guaranteed fuzzy logic controller for nuclear steam generators

    International Nuclear Information System (INIS)

    Cho, B.H.; No, H.C.

    1996-01-01

    A fuzzy logic controller (FLC) and a fuzzy logic filter (FLF), which have a special type of fuzzifier, inference engine, and defuzzifier, are applied to the water level control of a nuclear steam generator (S/G). It is shown that arbitrary two-input, single-output linear controllers can be adequately expressed by this FLC. A procedure to construct stability-guaranteed FLC rules is proposed. It contains the following steps: (1) the stable sector of linear feedback gains is obtained from the suboptimal concept based on LQR theory and the Lyapunov's stability criteria; (2) the stable sector of linear gains is mapped into two linear rule tables that are used as limits for the FLC rules; and (3) the construction of an FLC rule table is done by choosing certain rules that lie between these limits. This type of FLC guarantees asymptotic stability of the control system. The FLF generates a feedforward signal of S/G feedwater from the steam flow measurement using a fuzzy concept. Through computer simulation, it is found that the FLC with the FLF works better than a well-tuned PID controller with variable gains to reduce swell/shrink phenomena, especially for the water level deviation and abrupt steam flow disturbances that are typical in the existing power plants

  13. Dc microgrid stabilization through fuzzy control of interleaved, heterogeneous storage elements

    Science.gov (United States)

    Smith, Robert David

    As microgrid power systems gain prevalence and renewable energy comprises greater and greater portions of distributed generation, energy storage becomes important to offset the higher variance of renewable energy sources and maximize their usefulness. One of the emerging techniques is to utilize a combination of lead-acid batteries and ultracapacitors to provide both short and long-term stabilization to microgrid systems. The different energy and power characteristics of batteries and ultracapacitors imply that they ought to be utilized in different ways. Traditional linear controls can use these energy storage systems to stabilize a power grid, but cannot effect more complex interactions. This research explores a fuzzy logic approach to microgrid stabilization. The ability of a fuzzy logic controller to regulate a dc bus in the presence of source and load fluctuations, in a manner comparable to traditional linear control systems, is explored and demonstrated. Furthermore, the expanded capabilities (such as storage balancing, self-protection, and battery optimization) of a fuzzy logic system over a traditional linear control system are shown. System simulation results are presented and validated through hardware-based experiments. These experiments confirm the capabilities of the fuzzy logic control system to regulate bus voltage, balance storage elements, optimize battery usage, and effect self-protection.

  14. Extension and customization of self-stability control in compliant legged systems

    International Nuclear Information System (INIS)

    Ernst, M; Blickhan, R; Geyer, H

    2012-01-01

    Several recent studies on the control of legged locomotion in animal and robot running focus on the influence of different leg parameters on gait stability. In a preceding investigation self-stability controls showing deadbeat behavior could be obtained by studying the dynamics of the system in dependence of the leg orientation carefully adjusted during the flight phase. Such controls allow to accommodate disturbances of the ground level without having to detect them. Here we further this method in two ways. Besides the leg orientation, we allow changes in leg stiffness during flight and show that this extension substantially improves the rejection of ground disturbances. In a human like example the tolerance of random variation in ground level over many steps increased from 3.5% to 35% of leg length. In single steps changes of about 70% leg length (either up or down) could be negotiated. The variable leg stiffness not only allows to start with flat leg orientations maximizing step tolerances but also increase the control subspace. This allows to customize self-stability controls and to consider physical and technical limitations found in animals and robots. (paper)

  15. Fuzzy Logic Controller Stability Analysis Using a Satisfiability Modulo Theories Approach

    Science.gov (United States)

    Arnett, Timothy; Cook, Brandon; Clark, Matthew A.; Rattan, Kuldip

    2017-01-01

    While many widely accepted methods and techniques exist for validation and verification of traditional controllers, at this time no solutions have been accepted for Fuzzy Logic Controllers (FLCs). Due to the highly nonlinear nature of such systems, and the fact that developing a valid FLC does not require a mathematical model of the system, it is quite difficult to use conventional techniques to prove controller stability. Since safety-critical systems must be tested and verified to work as expected for all possible circumstances, the fact that FLC controllers cannot be tested to achieve such requirements poses limitations on the applications for such technology. Therefore, alternative methods for verification and validation of FLCs needs to be explored. In this study, a novel approach using formal verification methods to ensure the stability of a FLC is proposed. Main research challenges include specification of requirements for a complex system, conversion of a traditional FLC to a piecewise polynomial representation, and using a formal verification tool in a nonlinear solution space. Using the proposed architecture, the Fuzzy Logic Controller was found to always generate negative feedback, but inconclusive for Lyapunov stability.

  16. Improved Robust Stability Criterion of Networked Control Systems with Transmission Delays and Packet Loss

    Directory of Open Access Journals (Sweden)

    Shenping Xiao

    2014-01-01

    Full Text Available The problem of stability analysis for a class of networked control systems (NCSs with network-induced delay and packet dropout is investigated in this paper. Based on the working mechanism of zero-order holder, the closed-loop NCS is modeled as a continuous-time linear system with input delay. By introducing a novel Lyapunov-Krasovskii functional which splits both the lower and upper bounds of the delay into two subintervals, respectively, and utilizes reciprocally convex combination technique, a new stability criterion is derived in terms of linear matrix inequalities. Compared with previous results in the literature, the obtained stability criterion is less conservative. Numerical examples demonstrate the validity and feasibility of the proposed method.

  17. Partial stabilization and control of distributed parameter systems with elastic elements

    CERN Document Server

    Zuyev, Alexander L

    2015-01-01

     This monograph provides a rigorous treatment of problems related to partial asymptotic stability and controllability for models of flexible structures described by coupled nonlinear ordinary and partial differential equations or equations in abstract spaces. The text is self-contained, beginning with some basic results from the theory of continuous semigroups of operators in Banach spaces. The problem of partial asymptotic stability with respect to a continuous functional is then considered for a class of abstract multivalued systems on a metric space. Next, the results of this study are applied to the study of a rotating body with elastic attachments. Professor Zuyev demonstrates that the equilibrium cannot be made strongly asymptotically stable in the general case, motivating consideration of the problem of partial stabilization with respect to the functional that represents “averaged” oscillations. The book’s focus moves on to spillover analysis for infinite-dimensional systems with finite-dimensio...

  18. Frequency stabilization of a He-Ne gas laser by controlling refractive index of laser plasma

    International Nuclear Information System (INIS)

    Xie Yi; Wu Yizun

    1991-01-01

    A new way to stabilize the frequency of a Zeeman He-Ne gas laser is described. The laser frequency is stabilized by controlling the refractive index of the laser plasma. It does not need a gas laser tube with a piezoelectric ceramic (PZT) made by special technology. As the phase-locking technology is used in the laser servo system, the self-beat frequency is a constant and the frequency stability is better than 2.2 x 10 -11 (averaging time = 10 sec.). The long term frequency fluctuation never exceeded 2 x 10 -8 during two months. The frequency of the locked point can be adjusted continuously in the range of over 200 MHz

  19. Anfis Approach for Sssc Controller Design for the Improvement of Transient Stability Performance

    Science.gov (United States)

    Khuntia, Swasti R.; Panda, Sidhartha

    2011-06-01

    In this paper, Adaptive Neuro-Fuzzy Inference System (ANFIS) method based on the Artificial Neural Network (ANN) is applied to design a Static Synchronous Series Compensator (SSSC)-based controller for improvement of transient stability. The proposed ANFIS controller combines the advantages of fuzzy controller and quick response and adaptability nature of ANN. The ANFIS structures were trained using the generated database by fuzzy controller of SSSC. It is observed that the proposed SSSC controller improves greatly the voltage profile of the system under severe disturbances. The results prove that the proposed SSSC-based ANFIS controller is found to be robust to fault location and change in operating conditions. Further, the results obtained are compared with the conventional lead-lag controllers for SSSC.

  20. Stabilization and control of quad-rotor helicopter using a smartphone device

    Science.gov (United States)

    Desai, Alok; Lee, Dah-Jye; Moore, Jason; Chang, Yung-Ping

    2013-01-01

    In recent years, autonomous, micro-unmanned aerial vehicles (micro-UAVs), or more specifically hovering micro- UAVs, have proven suitable for many promising applications such as unknown environment exploration and search and rescue operations. The early versions of UAVs had no on-board control capabilities, and were difficult for manual control from a ground station. Many UAVs now are equipped with on-board control systems that reduce the amount of control required from the ground-station operator. However, the limitations on payload, power consumption and control without human interference remain the biggest challenges. This paper proposes to use a smartphone as the sole computational device to stabilize and control a quad-rotor. The goal is to use the readily available sensors in a smartphone such as the GPS, the accelerometer, the rate-gyros, and the camera to support vision-related tasks such as flight stabilization, estimation of the height above ground, target tracking, obstacle detection, and surveillance. We use a quad-rotor platform that has been built in the Robotic Vision Lab at Brigham Young University for our development and experiments. An Android smartphone is connected through the USB port to an external hardware that has a microprocessor and circuitries to generate pulse-width modulation signals to control the brushless servomotors on the quad-rotor. The high-resolution camera on the smartphone is used to detect and track features to maintain a desired altitude level. The vision algorithms implemented include template matching, Harris feature detector, RANSAC similarity-constrained homography, and color segmentation. Other sensors are used to control yaw, pitch, and roll of the quad-rotor. This smartphone-based system is able to stabilize and control micro-UAVs and is ideal for micro-UAVs that have size, weight, and power limitations.