WorldWideScience

Sample records for control scheme study

  1. Study on noise prediction model and control schemes for substation.

    Science.gov (United States)

    Chen, Chuanmin; Gao, Yang; Liu, Songtao

    2014-01-01

    With the government's emphasis on environmental issues of power transmission and transformation project, noise pollution has become a prominent problem now. The noise from the working transformer, reactor, and other electrical equipment in the substation will bring negative effect to the ambient environment. This paper focuses on using acoustic software for the simulation and calculation method to control substation noise. According to the characteristics of the substation noise and the techniques of noise reduction, a substation's acoustic field model was established with the SoundPLAN software to predict the scope of substation noise. On this basis, 4 reasonable noise control schemes were advanced to provide some helpful references for noise control during the new substation's design and construction process. And the feasibility and application effect of these control schemes can be verified by using the method of simulation modeling. The simulation results show that the substation always has the problem of excessive noise at boundary under the conventional measures. The excess noise can be efficiently reduced by taking the corresponding noise reduction methods.

  2. Experimental Study on Intelligent Control Scheme for Fan Coil Air-Conditioning System

    Directory of Open Access Journals (Sweden)

    Yanfeng Li

    2013-01-01

    Full Text Available An intelligent control scheme for fan coil air-conditioning systems has been put forward in order to overcome the shortcomings of the traditional proportion-integral-derivative (PID control scheme. These shortcomings include the inability of anti-interference and large inertia. An intelligent control test rig of fan coil air-conditioning system has been built, and MATLAB/Simulink dynamics simulation software has been adopted to implement the intelligent control scheme. A software for data exchange has been developed to combine the intelligence control system and the building automation (BA system. Experimental tests have been conducted to investigate the effectiveness of different control schemes including the traditional PID control, fuzzy control, and fuzzy-PID control for fan coil air-conditioning system. The effects of control schemes have been compared and analyzed in robustness, static and dynamic character, and economy. The results have shown that the developed data exchange interface software can induce the intelligent control scheme of the BA system more effectively. Among the proposed control strategies, fuzzy-PID control scheme which has the advantages of both traditional PID and fuzzy schemes is the optimal control scheme for the fan coil air-conditioning system.

  3. Study on Control Scheme for the Inverters in Low Voltage Microgrid with Nonlinear Loads

    Science.gov (United States)

    Xu, Jiqiang; Lu, Wenzhou; Wu, Lei

    2017-05-01

    There are a lot of nonlinear loads in real low voltage microgrid system. It will cause serious output voltage and grid current harmonic distortions problems in island and grid-connected modes, respectively. To solve this problem, this paper proposes a droop control scheme with quasi-proportion and resonant (quasi-PR) controller based on αβ stationary reference frame to make microgrid smoothly switch between grid-connected and island modes without changing control method. Moreover, in island mode, not only stable output voltage and frequency, but also reduced output voltage harmonics with added nonlinear loads can be achieved; In grid-connected mode, not only constant power, but also reduced grid current harmonics can be achieved. Simulation results verify the effectiveness of the proposed control scheme.

  4. A study of temperature sensor location based on fractal analysis for cascade control schemes in tubular reactors

    DEFF Research Database (Denmark)

    Eduardo Ramirez-Castelan, Carlos; Moguel-Castañeda, Jazael; Puebla, Hector

    2016-01-01

    Temperature sensor location for cascade control schemes in tubular reactors is still an open research problem. Several studies have pointed out that most temperature sensitive zones along the length of the reactor are suitable to this end. In this work, we have studied the problem of sensor...... location in a cascade control configuration using fractal analysis of time series obtained by random forcing of the jacket rector. A benchmark dispersion axial model displaying different temperature profiles is used to illustrate our findings....

  5. Mask roughness induced LER control and mitigation: aberrations sensitivity study and alternate illumination scheme

    Science.gov (United States)

    McClinton, Brittany M.; Naulleau, Patrick P.

    2011-04-01

    Here we conduct a mask-roughness-induced line-edge-roughness (LER) aberrations sensitivity study both as a random distribution amongst the first 16 Fringe Zernikes (for overall aberration levels of 0.25, 0.50, and 0.75nm rms) as well as an individual aberrations sensitivity matrix over the first 37 Fringe Zernikes. Full 2D aerial image modeling for an imaging system with NA = 0.32 was done for both the 22-nm and 16-nm half-pitch nodes on a rough mask with a replicated surface roughness (RSR) of 100 pm and a correlation length of 32 nm at the nominal extreme-ultraviolet lithography (EUVL) wavelength of 13.5nm. As the ideal RSR value for commercialization of EUVL is 50 pm and under, and furthermore as has been shown elsewhere, a correlation length of 32 nm of roughness on the mask sits on the peak LER value for an NA = 0.32 imaging optic, these mask roughness values and consequently the aberration sensitivity study presented here, represent a worst-case scenario. The illumination conditions were chosen based on the possible candidates for the 22-nm and 16-nm half-pitch nodes, respectively. In the 22-nm case, a disk illumination setting of σ = 0.50 was used, and for the 16-nm case, crosspole illumination with σ = 0.10 at an optimum offset of dx = 0 and dy = .67 in sigma space. In examining how to mitigate mask roughness induced LER, we considered an alternate illumination scheme whereby a traditional dipole's angular spectrum is extended in the direction parallel to the line-and-space mask absorber pattern to represent a "strip". While this illumination surprisingly provides minimal improvement to the LER as compared to several alternate illumination schemes, the overall imaging quality in terms of image-log-slope (ILS) and contrast is improved.

  6. Study of Direct Torque Controlled 3-phase SCIM with Two and Three-level Inverters using ST-DTC and FR-DTC scheme

    Directory of Open Access Journals (Sweden)

    P. R. Tripathy

    2015-02-01

    Full Text Available DTC control strategy helps to obtain fast and smooth control in 3–phase induction motors. It does not depend upon the machine parameters and transformation of reference frames. Various control strategies on the Direct Torque Control (DTC scheme have been carried out in the present study. The suggested scheme is meant for designing the low cost control circuit for DTC implementation on 3-phase SCIM. Three schemes with two types of inverters have been simulated in MATLAB (Simulink environment and the THD ratio in each case has been studied along with Fast Fourier Transform (FFT tools to compare the advantages.

  7. Effectiveness of a behavioral incentive scheme linked to goal achievement: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Redfern, Julie; Enright, Gemma; Raadsma, Simon; Allman-Farinelli, Margaret; Innes-Hughes, Christine; Khanal, Santosh; Khanal, Santash; Lukeis, Sarah; Rissel, Chris; Gyani, Alex

    2016-01-16

    Childhood obesity is a concern in Australia and across the world. Community-based weight management programs are an important response to address childhood obesity. However, the scientific literature suggests that their effectiveness could potentially be enhanced by providing a structured incentive scheme. This proposal aims to determine the effectiveness of enhanced goal setting linked to a structured incentive scheme designed to improve the sustained health and wellbeing of overweight/obese children within the context of an existing community-based program. This study is a cluster randomized controlled trial delivered within the context of the existing NSW "Go4Fun" program with a 10-week and 6- and 12-month follow-up (n = 40 sites, 570 participants) that compares the effectiveness of small changes to the program in which children were asked to set goals (supported by text messages) and were given rewards for achieving them (intervention). This will be compared to the standard/existing program (control), which did not have the same structured incentive program. Data will be collected for all participants at baseline, end of program, and at 6 and 12 months. The primary outcome is a mean change in body mass index (BMI) z score at the 12-month follow-up. Secondary outcomes include anthropometric measures (body weight, height, and waist circumference) and behavioral measures collected via validated questionnaires. A process evaluation (comprising surveys and focus groups) to determine acceptability and sustainability and to inform downstream translation will also be conducted. This study will inform policy and program delivery as well as the broader evidence base regarding goal achievement and incentive schemes directed at children's health-related behaviors and will provide evidence that is likely to be transferrable across a range of health conditions. ACTRN12615000558527 registered on 29 May 2015.

  8. Cerberus, an Access Control Scheme for Enforcing Least Privilege in Patient Cohort Study Platforms : A Comprehensive Access Control Scheme Applied to the GENIDA Project - Study of Genetic Forms of Intellectual Disabilities and Autism Spectrum Disorders.

    Science.gov (United States)

    Parrend, Pierre; Mazzucotelli, Timothée; Colin, Florent; Collet, Pierre; Mandel, Jean-Louis

    2017-11-16

    Cohort Study Platforms (CSP) are emerging as a key tool for collecting patient information, providing new research data, and supporting family and patient associations. However they pose new ethics and regulatory challenges since they cross the gap between patients and medical practitioners. One of the critical issues for CSP is to enforce a strict control on access privileges whilst allowing the users to take advantage of the breadth of the available data. We propose Cerberus, a new access control scheme spanning the whole life-cycle of access right management: design, implementation, deployment and maintenance, operations. Cerberus enables switching from a dual world, where CSP data can be accessed either from the users who entered it or fully de-identified, to an access-when-required world, where patients, practitioners and researchers can access focused medical data through explicit authorisation by the data owner. Efficient access control requires application-specific access rights, as well as the ability to restrict these rights when they are not used. Cerberus is implemented and evaluated in the context of the GENIDA project, an international CSP for Genetically determined Intellectual Disabilities and Autism Spectrum Disorders. As a result of this study, the software is made available for the community, and validated specifications for CSPs are given.

  9. Importance Sampling Based Decision Trees for Security Assessment and the Corresponding Preventive Control Schemes: the Danish Case Study

    DEFF Research Database (Denmark)

    Liu, Leo; Rather, Zakir Hussain; Chen, Zhe

    2013-01-01

    Decision Trees (DT) based security assessment helps Power System Operators (PSO) by providing them with the most significant system attributes and guiding them in implementing the corresponding emergency control actions to prevent system insecurity and blackouts. DT is obtained offline from time......-domain simulation and the process of data mining, which is then implemented online as guidelines for preventive control schemes. An algorithm named Classification and Regression Trees (CART) is used to train the DT and key to this approach lies on the accuracy of DT. This paper proposes contingency oriented DT...

  10. Study on control schemes of flexible steering system of a multi-axle all-wheel-steering robot

    Directory of Open Access Journals (Sweden)

    Pingxia Zhang

    2016-05-01

    Full Text Available It is well known that a multi-axle wheeled robot possesses larger load capability and also higher drive performance. However, its steering flexibility is degraded due to the large number of wheels. In order to solve this problem, in this article, we proposed three control schemes based on the center of rotation or the steering angles of both the first- and last-axle wheels. To release these control schemes, steering mode selection and also the left wheel’s steering angle in a specific axle are added approaching a practical application. Thereafter, the remaining wheels’ steering angles can be calculated with the Ackerman steering theorem. In order to verify the control effects, a five-axle all-wheel-steering wheeled robot has been developed with the Bluetooth wireless monitor system. Based on the newly designed robot, validation experiments are carried out, such as lateral movement, situ rotation, and multi-mode steering within a narrow space. The results indicate that the proposed design in this article can ensure a more flexible and faster movement within a narrow space. It shows large potential in obstacle avoidance compared with the conventional partial-wheel steering mode.

  11. Robust Model Predictive Control Schemes for Tracking Setpoints

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    Vu Trieu Minh

    2010-01-01

    Full Text Available This paper briefly reviews the development of nontracking robust model predictive control (RMPC schemes for uncertain systems using linear matrix inequalities (LMIs subject to input saturated and softened state constraints. Then we develop two new tracking setpoint RMPC schemes with common Lyapunov function and with zero terminal equality subject to input saturated and softened state constraints. The novel tracking setpoint RMPC schemes are able to stabilize uncertain systems once the output setpoints lead to the violation of the state constraints. The state violation can be regulated by changing the value of the weighting factor. A brief comparative simulation study of the two tracking setpoint RMPC schemes is done via simple examples to demonstrate the ability of the softened state constraint schemes. Finally, some features of future research from this study are discussed.

  12. Time-division-multiplex control scheme for voltage multiplier rectifiers

    Directory of Open Access Journals (Sweden)

    Bin-Han Liu

    2017-03-01

    Full Text Available A voltage multiplier rectifier with a novel time-division-multiplexing (TDM control scheme for high step-up converters is proposed in this study. In the proposed TDM control scheme, two full-wave voltage doubler rectifiers can be combined to realise a voltage quadrupler rectifier. The proposed voltage quadrupler rectifier can reduce transformer turn ratio and transformer size for high step-up converters and also reduce voltage stress for the output capacitors and rectifier diodes. An N-times voltage rectifier can be straightforwardly produced by extending the concepts from the proposed TDM control scheme. A phase-shift full-bridge (PSFB converter is adopted in the primary side of the proposed voltage quadrupler rectifier to construct a PSFB quadrupler converter. Experimental results for the PSFB quadrupler converter demonstrate the performance of the proposed TDM control scheme for voltage quadrupler rectifiers. An 8-times voltage rectifier is simulated to determine the validity of extending the proposed TDM control scheme to realise an N-times voltage rectifier. Experimental and simulation results show that the proposed TDM control scheme has great potential to be used in high step-up converters.

  13. Combined Control Scheme for Monitoring Quality Characteristics

    Directory of Open Access Journals (Sweden)

    Adekeye K.S.

    2014-07-01

    Full Text Available In the literature, the Exponentially Weighted Moving Average (EWMA and Exponentially Weighted Moving Variance (EMWV control schemes have been used separately to monitor the process average and process variability respectively. Here the two are combined and applied on simulated process with different level of variation. The control limit interval (CLI and the average run length (ARL were evaluated for the combined chart. The combined chart performed better than the two independently. Furthermore, an algorithm was developed for the two control charts and implemented on visual basic VB6.0. The obtained results show that the combined EWMA and EWMV control chart is very sensitive in detecting shift in production process and every shift in the process mean is always preceded by shift in the process variability.

  14. An improved auto-tuning scheme for PID controllers.

    Science.gov (United States)

    Dey, Chanchal; Mudi, Rajani K

    2009-10-01

    An improved auto-tuning scheme is proposed for Ziegler-Nichols (ZN) tuned PID controllers (ZNPIDs), which usually provide excessively large overshoots, not tolerable in most of the situations, for high-order and nonlinear processes. To overcome this limitation ZNPIDs are upgraded by some easily interpretable heuristic rules through an online gain modifying factor defined on the instantaneous process states. This study is an extension of our earlier work [Mudi RK., Dey C. Lee TT. An improved auto-tuning scheme for PI controllers. ISA Trans 2008; 47: 45-52] to ZNPIDs, thereby making the scheme suitable for a wide range of processes and more generalized too. The proposed augmented ZNPID (AZNPID) is tested on various high-order linear and nonlinear dead-time processes with improved performance over ZNPID, refined ZNPID (RZNPID), and other schemes reported in the literature. Stability issues are addressed for linear processes. Robust performance of AZNPID is observed while changing its tunable parameters as well as the process dead-time. The proposed scheme is also implemented on a real time servo-based position control system.

  15. Synchronization and Desynchronizing Control Schemes for Supermarket Refrigeration Systems

    DEFF Research Database (Denmark)

    Larsen, Lars Finn Sloth; Thybo, Claus Thybo; Izadi-Zamanabadi, Roozbeh

    2007-01-01

    A supermarket refrigeration system is a hybrid system with switched nonlinear dynamics and discrete-valued input variables such as opening/closing of valves and start/stop of compressors. Practical and simulation studies have shown that the use of distributed hysteresis controllers to operate...... the valves leads to synchronization, meaning that the opening and closing actions of the valves coincide. Consequently, the compressor periodically has to work hard resulting in low efficiency, inferior control performance and a high wear on the compressor. In this paper we propose two control schemes of low...... complexity for desynchronizing the valve operations while improving performance. Simulation results indicate the potential increase in efficiency and reduction in wear comparing with traditional control schemes....

  16. An optimal performance control scheme for a 3D crane

    Science.gov (United States)

    Maghsoudi, Mohammad Javad; Mohamed, Z.; Husain, A. R.; Tokhi, M. O.

    2016-01-01

    This paper presents an optimal performance control scheme for control of a three dimensional (3D) crane system including a Zero Vibration shaper which considers two control objectives concurrently. The control objectives are fast and accurate positioning of a trolley and minimum sway of a payload. A complete mathematical model of a lab-scaled 3D crane is simulated in Simulink. With a specific cost function the proposed controller is designed to cater both control objectives similar to a skilled operator. Simulation and experimental studies on a 3D crane show that the proposed controller has better performance as compared to a sequentially tuned PID-PID anti swing controller. The controller provides better position response with satisfactory payload sway in both rail and trolley responses. Experiments with different payloads and cable lengths show that the proposed controller is robust to changes in payload with satisfactory responses.

  17. Secure Dynamic access control scheme of PHR in cloud computing.

    Science.gov (United States)

    Chen, Tzer-Shyong; Liu, Chia-Hui; Chen, Tzer-Long; Chen, Chin-Sheng; Bau, Jian-Guo; Lin, Tzu-Ching

    2012-12-01

    With the development of information technology and medical technology, medical information has been developed from traditional paper records into electronic medical records, which have now been widely applied. The new-style medical information exchange system "personal health records (PHR)" is gradually developed. PHR is a kind of health records maintained and recorded by individuals. An ideal personal health record could integrate personal medical information from different sources and provide complete and correct personal health and medical summary through the Internet or portable media under the requirements of security and privacy. A lot of personal health records are being utilized. The patient-centered PHR information exchange system allows the public autonomously maintain and manage personal health records. Such management is convenient for storing, accessing, and sharing personal medical records. With the emergence of Cloud computing, PHR service has been transferred to storing data into Cloud servers that the resources could be flexibly utilized and the operation cost can be reduced. Nevertheless, patients would face privacy problem when storing PHR data into Cloud. Besides, it requires a secure protection scheme to encrypt the medical records of each patient for storing PHR into Cloud server. In the encryption process, it would be a challenge to achieve accurately accessing to medical records and corresponding to flexibility and efficiency. A new PHR access control scheme under Cloud computing environments is proposed in this study. With Lagrange interpolation polynomial to establish a secure and effective PHR information access scheme, it allows to accurately access to PHR with security and is suitable for enormous multi-users. Moreover, this scheme also dynamically supports multi-users in Cloud computing environments with personal privacy and offers legal authorities to access to PHR. From security and effectiveness analyses, the proposed PHR access

  18. Intelligent control schemes applied to Automatic Generation Control

    Directory of Open Access Journals (Sweden)

    Dingguo Chen

    2016-04-01

    Full Text Available Integrating ever increasing amount of renewable generating resources to interconnected power systems has created new challenges to the safety and reliability of today‟s power grids and posed new questions to be answered in the power system modeling, analysis and control. Automatic Generation Control (AGC must be extended to be able to accommodate the control of renewable generating assets. In addition, AGC is mandated to operate in accordance with the NERC‟s Control Performance Standard (CPS criteria, which represent a greater flexibility in relaxing the control of generating resources and yet assuring the stability and reliability of interconnected power systems when each balancing authority operates in full compliance. Enhancements in several aspects to the traditional AGC must be made in order to meet the aforementioned challenges. It is the intention of this paper to provide a systematic, mathematical formulation for AGC as a first attempt in the context of meeting the NERC CPS requirements and integrating renewable generating assets, which has not been seen reported in the literature to the best knowledge of the authors. Furthermore, this paper proposes neural network based predictive control schemes for AGC. The proposed controller is capable of handling complicated nonlinear dynamics in comparison with the conventional Proportional Integral (PI controller which is typically most effective to handle linear dynamics. The neural controller is designed in such a way that it has the capability of controlling the system generation in the relaxed manner so the ACE is controlled to a desired range instead of driving it to zero which would otherwise increase the control effort and cost; and most importantly the resulting system control performance meets the NERC CPS requirements and/or the NERC Balancing Authority’s ACE Limit (BAAL compliance requirements whichever are applicable.

  19. Adaptive Tracking Control for Robots With an Interneural Computing Scheme.

    Science.gov (United States)

    Tsai, Feng-Sheng; Hsu, Sheng-Yi; Shih, Mau-Hsiang

    2017-01-24

    Adaptive tracking control of mobile robots requires the ability to follow a trajectory generated by a moving target. The conventional analysis of adaptive tracking uses energy minimization to study the convergence and robustness of the tracking error when the mobile robot follows a desired trajectory. However, in the case that the moving target generates trajectories with uncertainties, a common Lyapunov-like function for energy minimization may be extremely difficult to determine. Here, to solve the adaptive tracking problem with uncertainties, we wish to implement an interneural computing scheme in the design of a mobile robot for behavior-based navigation. The behavior-based navigation adopts an adaptive plan of behavior patterns learning from the uncertainties of the environment. The characteristic feature of the interneural computing scheme is the use of neural path pruning with rewards and punishment interacting with the environment. On this basis, the mobile robot can be exploited to change its coupling weights in paths of neural connections systematically, which can then inhibit or enhance the effect of flow elimination in the dynamics of the evolutionary neural network. Such dynamical flow translation ultimately leads to robust sensory-to-motor transformations adapting to the uncertainties of the environment. A simulation result shows that the mobile robot with the interneural computing scheme can perform fault-tolerant behavior of tracking by maintaining suitable behavior patterns at high frequency levels.

  20. A Microprocessor Control Scheme For Switched Reluctance Motor Drives

    Science.gov (United States)

    Oza, A. R.; Krishnan, R.; Adkar, S.

    1987-10-01

    A microprocessor control scheme for a switched reluctance motor(SRM) drive is discussed. A SRM is inherently a variable speed machine since it requires a converter even for constant speed running. Starting with a conceptual development, a particular hardware scheme is discussed for controller implementation. Hardware-software tradeoffs incorporated in the design are discussed. Some results of an actual system are evaluated. It is shown that a microprocessor controller has many advantages over conventional controllers. The controller design uses rotor position and speed feedbacks. Self-starting is incorporated into the design. Use of off-the-shelf components makes the controller simple, reliable, and economical.

  1. An Industrial Model Based Disturbance Feedback Control Scheme

    DEFF Research Database (Denmark)

    Kawai, Fukiko; Nakazawa, Chikashi; Vinther, Kasper

    2014-01-01

    This paper presents a model based disturbance feedback control scheme. Industrial process systems have been traditionally controlled by using relay and PID controller. However these controllers are affected by disturbances and model errors and these effects degrade control performance. The authors...... propose a new control method that can decrease the negative impact of disturbance and model errors. The control method is motivated by industrial practice by Fuji Electric. Simulation tests are examined with a conventional PID controller and the disturbance feedback control. The simulation results...... demonstrate the effectiveness of the proposed method comparing with the conventional PID controller...

  2. Robust Fallback Scheme for the Danish Automatic Voltage Control System

    DEFF Research Database (Denmark)

    Qin, Nan; Dmitrova, Evgenia; Lund, Torsten

    2015-01-01

    This paper proposes a fallback scheme for the Danish automatic voltage control system. It will be activated in case of the local station loses telecommunication to the control center and/or the local station voltage violates the acceptable operational limits. It cuts in/out switchable and tap...

  3. Novel coupling scheme to control dynamics of coupled discrete systems

    Science.gov (United States)

    Shekatkar, Snehal M.; Ambika, G.

    2015-08-01

    We present a new coupling scheme to control spatio-temporal patterns and chimeras on 1-d and 2-d lattices and random networks of discrete dynamical systems. The scheme involves coupling with an external lattice or network of damped systems. When the system network and external network are set in a feedback loop, the system network can be controlled to a homogeneous steady state or synchronized periodic state with suppression of the chaotic dynamics of the individual units. The control scheme has the advantage that its design does not require any prior information about the system dynamics or its parameters and works effectively for a range of parameters of the control network. We analyze the stability of the controlled steady state or amplitude death state of lattices using the theory of circulant matrices and Routh-Hurwitz criterion for discrete systems and this helps to isolate regions of effective control in the relevant parameter planes. The conditions thus obtained are found to agree well with those obtained from direct numerical simulations in the specific context of lattices with logistic map and Henon map as on-site system dynamics. We show how chimera states developed in an experimentally realizable 2-d lattice can be controlled using this scheme. We propose this mechanism can provide a phenomenological model for the control of spatio-temporal patterns in coupled neurons due to non-synaptic coupling with the extra cellular medium. We extend the control scheme to regulate dynamics on random networks and adapt the master stability function method to analyze the stability of the controlled state for various topologies and coupling strengths.

  4. Hierarchical Control Scheme for Voltage Unbalance Compensation in Islanded Microgrids

    DEFF Research Database (Denmark)

    Savaghebi, Mehdi; Guerrero, Josep M.; Jalilian, Alireza

    2011-01-01

    The concept of microgrid hierarchical control is presented, recently. In this paper, a hierarchical scheme which includes primary and secondary control levels is proposed for islanded microgrids. The primary control level consists of DG local controllers. Local controller of each DG comprises...... active and reactive power controllers, virtual impedance loop and voltage and current controllers. The secondary level is designed to compensate the voltage unbalance at the load bus (LB) of the islanded microgrid. Also, restoration of LB voltage amplitude and microgrid frequency to the rated values...

  5. Fault tolerant control schemes using integral sliding modes

    CERN Document Server

    Hamayun, Mirza Tariq; Alwi, Halim

    2016-01-01

    The key attribute of a Fault Tolerant Control (FTC) system is its ability to maintain overall system stability and acceptable performance in the face of faults and failures within the feedback system. In this book Integral Sliding Mode (ISM) Control Allocation (CA) schemes for FTC are described, which have the potential to maintain close to nominal fault-free performance (for the entire system response), in the face of actuator faults and even complete failures of certain actuators. Broadly an ISM controller based around a model of the plant with the aim of creating a nonlinear fault tolerant feedback controller whose closed-loop performance is established during the design process. The second approach involves retro-fitting an ISM scheme to an existing feedback controller to introduce fault tolerance. This may be advantageous from an industrial perspective, because fault tolerance can be introduced without changing the existing control loops. A high fidelity benchmark model of a large transport aircraft is u...

  6. A hybrid iterative scheme for optimal control problems governed by ...

    African Journals Online (AJOL)

    This paper presents an iterative approach based on hybrid of perturbation and parametrization methods for obtaining approximate solutions of optimal control problems governed by some Fredholm integral equations. By some numerical examples, it is emphasized that this scheme is very effective and it produces ...

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

    DEFF Research Database (Denmark)

    Vardhan Krishnamachari, Vishnu; Andresen, Esben Ravn; Potma, Eric Olaf

    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 b...... 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....

  8. a comparative study of prioritized handoff schemes with guard

    African Journals Online (AJOL)

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    A COMPARATIVE STUDY OF PRIORITIZED HANDOFF SCHEMES WITH GUARD CHANNELS IN WIRELESS NETWORKS. D. U. Onyishi. D. U. Onyishi, et al. Nigerian Journal of Technology. Vol. 34, No. 3, July 2015 600 application of resource allocation schemes.This gives precedence to handoff calls. Such schemes ...

  9. Knowledge-Based Trajectory Error Pattern Method Applied to an Active Force Control Scheme

    Directory of Open Access Journals (Sweden)

    Endra Pitowarno, Musa Mailah, Hishamuddin Jamaluddin

    2012-08-01

    Full Text Available The active force control (AFC method is known as a robust control scheme that dramatically enhances the performance of a robot arm particularly in compensating the disturbance effects. The main task of the AFC method is to estimate the inertia matrix in the feedback loop to provide the correct (motor torque required to cancel out these disturbances. Several intelligent control schemes have already been introduced to enhance the estimation methods of acquiring the inertia matrix such as those using neural network, iterative learning and fuzzy logic. In this paper, we propose an alternative scheme called Knowledge-Based Trajectory Error Pattern Method (KBTEPM to suppress the trajectory track error of the AFC scheme. The knowledge is developed from the trajectory track error characteristic based on the previous experimental results of the crude approximation method. It produces a unique, new and desirable error pattern when a trajectory command is forced. An experimental study was performed using simulation work on the AFC scheme with KBTEPM applied to a two-planar manipulator in which a set of rule-based algorithm is derived. A number of previous AFC schemes are also reviewed as benchmark. The simulation results show that the AFC-KBTEPM scheme successfully reduces the trajectory track error significantly even in the presence of the introduced disturbances.Key Words:  Active force control, estimated inertia matrix, robot arm, trajectory error pattern, knowledge-based.

  10. Anti-Windup Scheme for Practical Control of Positioning Systems

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    Wahyudi Tarig Faisal and Abdulgani Albagul

    2012-10-01

    Full Text Available Positioning systems generally need a good controller to achieve high accuracy, fast response and robustness. In addition, ease of controller design and simplicity of controller structure are very important for practical application.  For satisfying these requirements, nominal characteristic trajectory following controller (NCTF has been proposed as a practical point-to-point (PTP positioning control. However, the effect of actuator saturation can not be completely compensated for due to the integrator windup as the plant parameters vary. This paper presents a method to improve the NCTF controller for overcoming the problem of integrator windup using simple and classical tracking anti-windup scheme. The improved NCTF controller is evaluated through simulation using a rotary positioning system. The results show that the improved NCTF controller is adequate to compensate for the effect of integrator windup. Keywords: Positioning, point-to-point, integrator windup, compensation, controller, robustness.

  11. Turbulent boundary layer under the control of different schemes

    Science.gov (United States)

    Qiao, Z. X.; Zhou, Y.; Wu, Z.

    2017-06-01

    This work explores experimentally the control of a turbulent boundary layer over a flat plate based on wall perturbation generated by piezo-ceramic actuators. Different schemes are investigated, including the feed-forward, the feedback, and the combined feed-forward and feedback strategies, with a view to suppressing the near-wall high-speed events and hence reducing skin friction drag. While the strategies may achieve a local maximum drag reduction slightly less than their counterpart of the open-loop control, the corresponding duty cycles are substantially reduced when compared with that of the open-loop control. The results suggest a good potential to cut down the input energy under these control strategies. The fluctuating velocity, spectra, Taylor microscale and mean energy dissipation are measured across the boundary layer with and without control and, based on the measurements, the flow mechanism behind the control is proposed.

  12. Turbulent boundary layer under the control of different schemes.

    Science.gov (United States)

    Qiao, Z X; Zhou, Y; Wu, Z

    2017-06-01

    This work explores experimentally the control of a turbulent boundary layer over a flat plate based on wall perturbation generated by piezo-ceramic actuators. Different schemes are investigated, including the feed-forward, the feedback, and the combined feed-forward and feedback strategies, with a view to suppressing the near-wall high-speed events and hence reducing skin friction drag. While the strategies may achieve a local maximum drag reduction slightly less than their counterpart of the open-loop control, the corresponding duty cycles are substantially reduced when compared with that of the open-loop control. The results suggest a good potential to cut down the input energy under these control strategies. The fluctuating velocity, spectra, Taylor microscale and mean energy dissipation are measured across the boundary layer with and without control and, based on the measurements, the flow mechanism behind the control is proposed.

  13. Advanced Energy Harvesting Control Schemes for Marine Renewable Energy Devices

    Energy Technology Data Exchange (ETDEWEB)

    McEntee, Jarlath [Ocean Renewable Power Company, Portland, ME (United States); Polagye, Brian [Ocean Renewable Power Company, Portland, ME (United States); Fabien, Brian [Ocean Renewable Power Company, Portland, ME (United States); Thomson, Jim [Ocean Renewable Power Company, Portland, ME (United States); Kilcher, Levi [Ocean Renewable Power Company, Portland, ME (United States); Marnagh, Cian [Ocean Renewable Power Company, Portland, ME (United States); Donegan, James [Ocean Renewable Power Company, Portland, ME (United States)

    2016-03-31

    The Advanced Energy Harvesting Control Schemes for Marine Renewable Energy Devices (Project) investigated, analyzed and modeled advanced turbine control schemes with the objective of increasing the energy harvested by hydrokinetic turbines in turbulent flow. Ocean Renewable Power Company (ORPC) implemented and validated a feedforward controller to increase power capture; and applied and tested the controls on ORPC’s RivGen® Power Systems in Igiugig, Alaska. Assessments of performance improvements were made for the RivGen® in the Igiugig environment and for ORPC’s TidGen® Power System in a reference tidal environment. Annualized Energy Production (AEP) and Levelized Cost of Energy (LCOE) improvements associated with implementation of the recommended control methodology were made for the TidGen® Power System in the DOE reference tidal environment. System Performance Advancement (SPA) goals were selected for the project. SPA targets were to improve Power to Weight Ratio (PWR) and system Availability, with the intention of reducing Levelized Cost of Electricity (LCOE). This project focused primarily reducing in PWR. Reductions in PWR of 25.5% were achieved. Reductions of 20.3% in LCOE were achieved. This project evaluated four types of controllers which were tested in simulation, emulation, a laboratory flume, and the field. The adaptive Kω2 controller performs similarly to the non-adaptive version of the same controller and may be useful in tidal channels where the mean velocity is continually evolving. Trends in simulation were largely verified through experiments, which also provided the opportunity to test assumptions about turbine responsiveness and control resilience to varying scales of turbulence. Laboratory experiments provided an essential stepping stone between simulation and implementation on a field-scale turbine. Experiments also demonstrated that using “energy loss” as a metric to differentiate between well-designed controllers operating at

  14. A Global Sliding-Mode Control Scheme with Adjustable Robustness for A Linear Variable Reluctance Motor

    Science.gov (United States)

    Lin, Jin-Yuan; Lu, Yu-Sheng; Chen, Jian-Shiang

    A novel global sliding-mode control (GSMC) scheme with adjustable robustness is presented in this article. The proposed scheme offers a switching function together with unperturbed system dynamics to weigh the contribution from SMC such that all of the closed-loop poles can be located within predefined regions to provide design flexibility, and the robustness of system can thus be adjusted. By this scheme, the maximal control effort and chattering level can be reduced according to designer's specifications directly. Since the switching function can initially be made to equal to zero, the adjustable performance during the entire response can be guaranteed, and the reaching condition is thus lifted. The efficacy of this scheme is demonstrated via successful implementation on a linear variable reluctance motor (LVRM) servo system. Both simulation and experimental studies further demonstrate its feasibility and effectiveness.

  15. Planning Framework for Mesolevel Optimization of Urban Runoff Control Schemes

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Qianqian; Blohm, Andrew; Liu, Bo

    2017-04-01

    A planning framework is developed to optimize runoff control schemes at scales relevant for regional planning at an early stage. The framework employs less sophisticated modeling approaches to allow a practical application in developing regions with limited data sources and computing capability. The methodology contains three interrelated modules: (1)the geographic information system (GIS)-based hydrological module, which aims at assessing local hydrological constraints and potential for runoff control according to regional land-use descriptions; (2)the grading module, which is built upon the method of fuzzy comprehensive evaluation. It is used to establish a priority ranking system to assist the allocation of runoff control targets at the subdivision level; and (3)the genetic algorithm-based optimization module, which is included to derive Pareto-based optimal solutions for mesolevel allocation with multiple competing objectives. The optimization approach describes the trade-off between different allocation plans and simultaneously ensures that all allocation schemes satisfy the minimum requirement on runoff control. Our results highlight the importance of considering the mesolevel allocation strategy in addition to measures at macrolevels and microlevels in urban runoff management. (C) 2016 American Society of Civil Engineers.

  16. Observerless Scheme for Sensorless Speed Control of PMSM Using Direct Torque Control Method With LP Filter

    Directory of Open Access Journals (Sweden)

    BEKIROGLU, N.

    2010-08-01

    Full Text Available In this study, direct torque control (DTC of a permanent magnet synchronous motor is realized with a sensorless speed control technique without using an observer. Space vector pulse width modulation (SVPWM technique is applied in order to determine the switching sequence of the voltage source inverter. Torque and flux, the main variables of the DTC, are estimated by using the mathematical model of the motor. Estimated torque and flux values are compared with their references in every control cycle. Then, according to the torque and flux demand, the voltage vector is constituted. In the proposed control scheme, speed is estimated by using flux calculations and a PI controller is used to process the torque and flux errors. Furthermore, a low-pass (LP filter is implemented within the proposed system for voltage and current harmonics suppression. The results proved that proposed scheme for the DTC provides the speed control under various torque demands without employing a sensor. The proposed system performs very well for a sensorless operation and effectively eliminates the harmonics due to the LP filter.

  17. Performance Comparison of Grid-Faulty Control Schemes for Inverter-Based Industrial Microgrids

    Directory of Open Access Journals (Sweden)

    Antonio Camacho

    2017-12-01

    Full Text Available Several control schemes specifically designed to operate inverter-based industrial microgrids during voltage sags have been recently proposed. This paper first classifies these control schemes in three categories and then performs a comparative analysis of them. Representative control schemes of each category are selected, described and used to identify the main features and performance of the considered category. The comparison is based on the evaluation of several indexes, which measure the power quality of the installation and utility grid during voltage sags, including voltage regulation, reactive current injection and transient response. The paper includes selected simulation results from a 500 kVA industrial microgrid to validate the expected features of the considered control schemes. Finally, in view of the obtained results, the paper proposes an alternative solution to cope with voltage sags, which includes the use of a static compensator in parallel with the microgrid. The novelty of this proposal is the suitable selection of the control schemes for both the microgrid and the static compensator. The superior performance of the proposal is confirmed by the analysis of the quality indexes. Its practical limitations are also revealed, showing that the topic studied in this paper is still open for further research.

  18. Improving the Authentication Scheme and Access Control Protocol for VANETs

    Directory of Open Access Journals (Sweden)

    Wei-Chen Wu

    2014-11-01

    Full Text Available Privacy and security are very important in vehicular ad hoc networks (VANETs. VANETs are negatively affected by any malicious user’s behaviors, such as bogus information and replay attacks on the disseminated messages. Among various security threats, privacy preservation is one of the new challenges of protecting users’ private information. Existing authentication protocols to secure VANETs raise challenges, such as certificate distribution and reduction of the strong reliance on tamper-proof devices. In 2011, Yeh et al. proposed a PAACP: a portable privacy-preserving authentication and access control protocol in vehicular ad hoc networks. However, PAACP in the authorization phase is breakable and cannot maintain privacy in VANETs. In this paper, we present a cryptanalysis of an attachable blind signature and demonstrate that the PAACP’s authorized credential (AC is not secure and private, even if the AC is secretly stored in a tamper-proof device. An eavesdropper can construct an AC from an intercepted blind document. Any eavesdropper can determine who has which access privileges to access which service. For this reason, this paper copes with these challenges and proposes an efficient scheme. We conclude that an improving authentication scheme and access control protocol for VANETs not only resolves the problems that have appeared, but also is more secure and efficient.

  19. Bearingless Flywheel Systems, Winding and Control Schemes, and Sensorless Control

    Science.gov (United States)

    Jansen, Ralph H (Inventor); Trase, Larry M (Inventor); Dever, Timothy P (Inventor); Kascak, Peter E (Inventor); Kraft, Thomas G (Inventor)

    2016-01-01

    Flywheel systems are disclosed that provide increased energy density and operational effectiveness. A first bearingless motor and a second bearingless motor may be configured to simultaneously suspend the central rotor in a radial direction and to rotate the central rotor. However, certain implementations may have one motor or more than two motors, depending on the design. A plurality of the flywheel systems may be collectively controlled to perform community energy storage with higher storage capacities than individual flywheel systems.

  20. Efficient rate control scheme using modified inter-layer dependency ...

    Indian Academy of Sciences (India)

    In this paper, a spatial-resolutionratio-based MB mode decision scheme is proposed for spatially enhanced layers. The scheme uses the motion estimated at the base layer, to encode the respective MBs in the enhancement layers. The spatial–temporalsearch schemes at the enhancement layers are used to derive motion ...

  1. Farmer Attitudes and Livestock Disease: Exploring Citizenship Behaviour and Peer Monitoring across Two BVD Control Schemes in the UK.

    Directory of Open Access Journals (Sweden)

    Claire Heffernan

    Full Text Available The eradication of BVD in the UK is technically possible but appears to be socially untenable. The following study explored farmer attitudes to BVD control schemes in relation to advice networks and information sharing, shared aims and goals, motivation and benefits of membership, notions of BVD as a priority disease and attitudes toward regulation. Two concepts from the organisational management literature framed the study: citizenship behaviour where actions of individuals support the collective good (but are not explicitly recognised as such and peer to peer monitoring (where individuals evaluate other's behaviour. Farmers from two BVD control schemes in the UK participated in the study: Orkney Livestock Association BVD Eradication Scheme and Norfolk and Suffolk Cattle Breeders Association BVD Eradication Scheme. In total 162 farmers participated in the research (109 in-scheme and 53 out of scheme. The findings revealed that group helping and information sharing among scheme members was low with a positive BVD status subject to social censure. Peer monitoring in the form of gossip with regard to the animal health status of other farms was high. Interestingly, farmers across both schemes supported greater regulation with regard to animal health, largely due to the mistrust of fellow farmers following voluntary disease control measures. While group cohesiveness varied across the two schemes, without continued financial inducements, longer-term sustainability is questionable.

  2. Farmer Attitudes and Livestock Disease: Exploring Citizenship Behaviour and Peer Monitoring across Two BVD Control Schemes in the UK.

    Science.gov (United States)

    Heffernan, Claire; Azbel-Jackson, Lena; Brownlie, Joe; Gunn, George

    2016-01-01

    The eradication of BVD in the UK is technically possible but appears to be socially untenable. The following study explored farmer attitudes to BVD control schemes in relation to advice networks and information sharing, shared aims and goals, motivation and benefits of membership, notions of BVD as a priority disease and attitudes toward regulation. Two concepts from the organisational management literature framed the study: citizenship behaviour where actions of individuals support the collective good (but are not explicitly recognised as such) and peer to peer monitoring (where individuals evaluate other's behaviour). Farmers from two BVD control schemes in the UK participated in the study: Orkney Livestock Association BVD Eradication Scheme and Norfolk and Suffolk Cattle Breeders Association BVD Eradication Scheme. In total 162 farmers participated in the research (109 in-scheme and 53 out of scheme). The findings revealed that group helping and information sharing among scheme members was low with a positive BVD status subject to social censure. Peer monitoring in the form of gossip with regard to the animal health status of other farms was high. Interestingly, farmers across both schemes supported greater regulation with regard to animal health, largely due to the mistrust of fellow farmers following voluntary disease control measures. While group cohesiveness varied across the two schemes, without continued financial inducements, longer-term sustainability is questionable.

  3. Research on cooperative vehicle intersection control scheme without using traffic lights under the connected vehicles environment

    National Research Council Canada - National Science Library

    Zheng, Yi; Jin, Lisheng; Jiang, Yuying; Wang, Fangrong; Guan, Xin; Ji, Shengyuan; Xu, Jun

    2017-01-01

    To improve traffic congestion of urban intersections, this article presents a cooperative vehicle intersection control scheme without using any traffic lights, based on model predictive control theory...

  4. NEURAL CASCADED WITH FUZZY SCHEME FOR CONTROL OF A HYDROELECTRIC POWER PLANT

    OpenAIRE

    A. Selwin Mich Priyadharson; T. Ramesh Kumar; M. S. Saravanan; C. ThilipKumar; D. Dileepan

    2014-01-01

    A novel design for flow and level control in a hydroelectric power plant using Programmable Logic Controller (PLC)-Human Machine Interface (HMI) and neural cascaded with fuzzy scheme is proposed. This project will focus on design and development of flow and level controller for small scale hydro generating units by implementing gate control based on PLC-HMI with the proposed scheme. The existing control schemes have so many difficulties to manage intrinsic time delay, nonlinearity due to unce...

  5. On a switching control scheme for nonlinear systems with ill-defined relative degree

    OpenAIRE

    Chen, W-H; Ballance, D.J.

    2002-01-01

    This paper discusses the applicability of a switching control scheme for a nonlinear system with ill-defined relative degree. The control scheme switches between exact and approximate input-output linearisation control laws. Unlike a linear system under a switching control scheme, the equilibria of a nonlinear system may change with the switching. It is pointed out that this is not sufficient to cause instability. When the region of the approximate linearisation control law is attractive to t...

  6. Controllability of Boolean networks via input controls under Harvey's update scheme

    Science.gov (United States)

    Luo, Chao; Zhang, Xiaolin; Shao, Rui; Zheng, YuanJie

    2016-02-01

    In this article, the controllability of Boolean networks via input controls under Harvey's update scheme is investigated. First, the model of Boolean control networks under Harvey's stochastic update is proposed, by means of semi-tensor product approach, which is converted into discrete-time linear representation. And, a general formula of control-depending network transition matrix is provided. Second, based on discrete-time dynamics, controllability of the proposed model is analytically discussed by revealing the necessary and sufficient conditions of the reachable sets, respectively, for three kinds of controls, i.e., free Boolean control sequence, input control networks, and close-loop control. Examples are showed to demonstrate the effectiveness and feasibility of the proposed scheme.

  7. Sensor scheme design for active structural acoustic control

    NARCIS (Netherlands)

    Berkhoff, Arthur P.

    Efficient sensing schemes for the active reduction of sound radiation from plates are presented based on error signals derived from spatially weighted plate velocity or near-field pressure. The schemes result in near-optimal reductions as compared to weighting procedures derived from eigenvector or

  8. 31 CFR 592.301 - Controlled through the Kimberley Process Certification Scheme.

    Science.gov (United States)

    2010-07-01

    ... Process Certification Scheme. 592.301 Section 592.301 Money and Finance: Treasury Regulations Relating to... Certification Scheme. (a) Except as otherwise provided in paragraph (b) of this section, the term controlled through the Kimberley Process Certification Scheme refers to the following requirements that apply, as...

  9. Community-applied research of a traditional Chinese medicine rehabilitation scheme on Broca's aphasia after stroke: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Tao, Jing; Fang, Yunhua; Wu, Zhenkai; Rao, Ting; Su, Yusheng; Lin, Lili; Liu, Wei; Wu, Jinsong; Yang, Shanli; Zheng, Guohua; Chen, Lidian

    2014-07-21

    Aphasia is a common and severely disabling complication in stroke patients. It usually brings about lower rates of functional recovery, longer rehabilitation length of stay (LOS), and significantly poorer LOS efficiency (LOS-Eff), resulting in higher rehabilitation costs compared to patients without aphasia. It also decreases the quality of life and increases the mortality of stroke patients. The evidence currently available suggests that the effect of acupuncture combined with language training for apoplectic aphasia is statistically better than speech and language therapy (SLT) alone, but there remains a lack of high-quality randomized controlled trials. Acupuncture combined with language training is relatively low-cost and especially suitable for community-based rehabilitation for aphasia patients after stroke, taking its medical and health facilities which are always deficient in manpower and material resources into account. The aim of the present study is to develop an effective standard therapeutic program for apoplectic aphasia in communities. In a randomized controlled clinical trial with blinded assessment, 290 eligible patients with aphasia due to stroke will be randomly allocated into a control group or an experimental group. The course of this trial will comprise a 4-week intervention and a 12-week follow-up period. Five assessment points, including baseline, 2 and 4 weeks after treatment, 6 and 12 weeks after follow-up, are set to dynamically observe the changes of curative effects. Primary outcome measures are the differences in the score on both the China rehabilitation research center aphasia examination (CRRCAE) and Boston diagnostic aphasia examination - Chinese version (BDAE-C) after intervention and follow-up. The Modified Barthel Index (MBI), 36-Item Short Form Health Survey (SF-36), and results of blood oxygen level dependent-functional magnetic resonance imaging (BOLD-fMRI) examination are considered as the secondary outcome measures. Other

  10. Controllable and Anonymous Authentication Scheme for Space Networks

    Directory of Open Access Journals (Sweden)

    Hu Zhi-Yan

    2017-01-01

    Full Text Available This paper analyzed the existing anonymous authentication schemes which have the weakness of high calculation and communication cost and weak security. So we designed a secure and efficient anonymous authentication scheme to meet the need of the space network, which has the characteristic of resource limited, high exposure and intermittent connectivity. At first we proposed a signature algorithm based on certificateless public key cryptosystem and one-off public key, and then presented an anonymous authentication scheme according to the proposed signature algorithm, it needs two message interaction to complete the mutual authentication and key agreement. When the user has the illegal behavior, the service provider can reveal the illegal user’s real identity through cooperation with the trusted center. Compared with the similar literature, the proposed scheme achieves high security with low computation and communication cost. (Abstract

  11. Adaptive control schemes for mobile robot formations with triangularised structures

    NARCIS (Netherlands)

    Guo, J.; Lin, Z.; Cao, M.; Yan, G.

    The study investigates the leader-follower formation control problem, for which the objective is to control a group of robots such that they move as a rigid formation with a prescribed constant velocity. It is assumed in the study that there are two leader robots, who are the only robots in the

  12. A control scheme for filament stretching rheometers with application to polymer melts

    DEFF Research Database (Denmark)

    Román Marín, José Manuel; Huusom, Jakob Kjøbsted; Javier Alvarez, Nicolas

    2013-01-01

    We propose a new control scheme to maintain a constant strain rate of the mid-filament diameter in a filament stretching rheometer for polymer melts. The scheme is cast as a velocity algorithm and consists of a feed-back and a feed-forward contribution. The performance of the controller is demons......We propose a new control scheme to maintain a constant strain rate of the mid-filament diameter in a filament stretching rheometer for polymer melts. The scheme is cast as a velocity algorithm and consists of a feed-back and a feed-forward contribution. The performance of the controller...

  13. Simulation and stability analysis of neural network based control scheme for switched linear systems.

    Science.gov (United States)

    Singh, H P; Sukavanam, N

    2012-01-01

    This paper proposes a new adaptive neural network based control scheme for switched linear systems with parametric uncertainty and external disturbance. A key feature of this scheme is that the prior information of the possible upper bound of the uncertainty is not required. A feedforward neural network is employed to learn this upper bound. The adaptive learning algorithm is derived from Lyapunov stability analysis so that the system response under arbitrary switching laws is guaranteed uniformly ultimately bounded. A comparative simulation study with robust controller given in [Zhang L, Lu Y, Chen Y, Mastorakis NE. Robust uniformly ultimate boundedness control for uncertain switched linear systems. Computers and Mathematics with Applications 2008; 56: 1709-14] is presented. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

  14. Hierarchical Control Scheme for Voltage Harmonics Compensation in an Islanded Droop-Controlled Microgrid

    DEFF Research Database (Denmark)

    Savaghebi, Mehdi; Guerrero, Josep M.; Jalilian, Alireza

    2011-01-01

    controllers, and virtual impedance loop. A novel virtual impedance structure is proposed to achieve proper sharing of non-fundamental power among the microgrid DGs. The secondary level is designed to manage compensation of voltage harmonics at the microgrid load bus (LB) to which the sensitive loads may......In this paper, a microgrid hierarchical control scheme is proposed which includes primary and secondary control levels. The primary level comprises distributed generators (DGs) local controllers. The local controller mainly consists of active and reactive power controllers, voltage and current...

  15. Classmate Peer-Coaching: "A Study Buddy Support Scheme"

    Science.gov (United States)

    Thalluri, Jyothi; O'Flaherty, Jackie A.; Shepherd, Paul L.

    2014-01-01

    This study had two aims: firstly, to determine whether participation in a peer support scheme called Study Buddy Support (SBS) improves pass rates of "at risk" students, and secondly, to examine the advantages of this model over hierarchical models where senior students tutor junior years. Bachelor of Nursing and Midwifery students in a…

  16. Tegotae-based decentralised control scheme for autonomous gait transition of snake-like robots.

    Science.gov (United States)

    Kano, Takeshi; Yoshizawa, Ryo; Ishiguro, Akio

    2017-08-04

    Snakes change their locomotion patterns in response to the environment. This ability is a motivation for developing snake-like robots with highly adaptive functionality. In this study, a decentralised control scheme of snake-like robots that exhibited autonomous gait transition (i.e. the transition between concertina locomotion in narrow aisles and scaffold-based locomotion on unstructured terrains) was developed. Additionally, the control scheme was validated via simulations. A key insight revealed is that these locomotion patterns were not preprogrammed but emerged by exploiting Tegotae, a concept that describes the extent to which a perceived reaction matches a generated action. Unlike local reflexive mechanisms proposed previously, the Tegotae-based feedback mechanism enabled the robot to 'selectively' exploit environments beneficial for propulsion, and generated reasonable locomotion patterns. It is expected that the results of this study can form the basis to design robots that can work under unpredictable and unstructured environments.

  17. Indian Kisan Credit Card Scheme: An Analytical Study

    Directory of Open Access Journals (Sweden)

    Dharmendra Mehta

    2016-03-01

    Full Text Available Kisan Credit Card (KCC has now been regarded as the only medium of short-term credit for agriculture. The Kisan Credit Card (KCC scheme was introduced by the Finance Minister in his budget speech in the year 1998-99. From the year 1998-99, the scheme was implemented by public sector commercial banks, RRBs (Regional Rural Banks and cooperative banks in the country. It has emerged as an innovative credit distribution system to meet the production credit requirements of the farmers in a timely and easy manner. The present paper is aimed to study role of Kisan Credit Card in the rural credit facilitation in India.

  18. Controlling a pH Process Using Feedback & Double Controller Scheme

    Directory of Open Access Journals (Sweden)

    S. Shobana

    2009-09-01

    Full Text Available Control of pH, particularly, in industrial application, is difficult and challenging due to its time-varying and nonlinear nature of the chemical or biological process. This non-linearity does however suggest that pH control would be a suitable application area for a model based double-control system, whose ability to handle non-linearity is well known. The mathematical model of pH for a weak acid-strong base is used to design IMC based PID double-controller scheme which provides outstanding setpoint tracking and disturbances rejection simultaneously to control pH processes.

  19. Performance evaluation of time-delay control schemes for uninterruptible power supplies

    DEFF Research Database (Denmark)

    Loh, P.C; Tang, Y.; Blaabjerg, Frede

    2008-01-01

    transitions. Even more favorable is that the above-described performance features are attained under all load-operating conditions and at the same level of implementation easiness as for the traditional double-loop control scheme. Lastly, for verifying the practicality of the control schemes, an experimental...

  20. PI controller scheme for charge balance in implantable electrical ...

    Indian Academy of Sciences (India)

    Electrical stimulation has been used in a wide variety of medical implant applications. In all of these applications, due to safety concerns, maintaining charge balance becomes a critically important issue that needs to be addressed at the design stage. It is important that charge balancing schemes be robust to circuit ...

  1. A simple output voltage control scheme for single phase wavelet ...

    African Journals Online (AJOL)

    DR OKE

    Wavelet based techniques have been extensively used in various power engineering applications. Recently, wavelet has also been proposed to generate switching signal for single-phase pulse-width-modulated (PWM) dc-ac inverter. The main advantage of the wavelet modulated (WM) scheme is that a single synthesis ...

  2. Controlling a pH Process Using Feedback & Double Controller Scheme

    OpenAIRE

    S.Shobana; Srinivasan, A.; Rames C.Panda

    2009-01-01

    Control of pH, particularly, in industrial application, is difficult and challenging due to its time-varying and nonlinear nature of the chemical or biological process. This non-linearity does however suggest that pH control would be a suitable application area for a model based double-control system, whose ability to handle non-linearity is well known. The mathematical model of pH for a weak acid-strong base is used to design IMC based PID double-controller scheme which provides outstanding ...

  3. Universal block diagram based modeling and simulation schemes for fractional-order control systems.

    Science.gov (United States)

    Bai, Lu; Xue, Dingyü

    2017-05-08

    Universal block diagram based schemes are proposed for modeling and simulating the fractional-order control systems in this paper. A fractional operator block in Simulink is designed to evaluate the fractional-order derivative and integral. Based on the block, the fractional-order control systems with zero initial conditions can be modeled conveniently. For modeling the system with nonzero initial conditions, the auxiliary signal is constructed in the compensation scheme. Since the compensation scheme is very complicated, therefore the integrator chain scheme is further proposed to simplify the modeling procedures. The accuracy and effectiveness of the schemes are assessed in the examples, the computation results testify the block diagram scheme is efficient for all Caputo fractional-order ordinary differential equations (FODEs) of any complexity, including the implicit Caputo FODEs. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  4. Wide-Area H∞ Control for Damping Interarea Oscillations with Event-Triggered Scheme

    Directory of Open Access Journals (Sweden)

    Yunning Zhang

    2013-01-01

    Full Text Available An event-triggered scheme is adopted and applied to the design of a centralized wide-area H∞ damping controller (WAHDC of interconnected power systems with external disturbance. Firstly, based on the linearized multimachine system model, the centralized WAHDC with event-triggered scheme design problem is described as time-delay feedback control problem. Then by using Lyapunov functional method and Jensen inequality technique, criteria for stability with an H∞ norm bound and for design of the feedback controller are derived. The linear matrix inequality (LMI is employed to solve the feedback gain. Finally, case studies are carried out based on two-area four-machine power system. Simulations indicate that the proposed WAHDC with event-triggered scheme can damp the interarea oscillation effectively when the external disturbance is bounded and significantly reduce the number of measured states released to WAHDC. Relationships between event trigger parameter σ and dynamic performance, σ and network utilization, σ and time delay, and σ and disturbance rejection level are investigated and results obtained can be used to choose an appropriate event trigger parameter.

  5. A Quantum Proxy Weak Blind Signature Scheme Based on Controlled Quantum Teleportation

    Science.gov (United States)

    Cao, Hai-Jing; Yu, Yao-Feng; Song, Qin; Gao, Lan-Xiang

    2015-04-01

    Proxy blind signature is applied to the electronic paying system, electronic voting system, mobile agent system, security of internet, etc. A quantum proxy weak blind signature scheme is proposed in this paper. It is based on controlled quantum teleportation. Five-qubit entangled state functions as quantum channel. The scheme uses the physical characteristics of quantum mechanics to implement message blinding, so it could guarantee not only the unconditional security of the scheme but also the anonymity of the messages owner.

  6. An Effective Method on Applying Feedback Error Learning Scheme to Functional Electrical Stimulation Controller

    Science.gov (United States)

    Watanabe, Takashi; Kurosawa, Kenji; Yoshizawa, Makoto

    A Feedback Error Learning (FEL) scheme was found to be applicable to joint angle control by Functional Electrical Stimulation (FES) in our previous study. However, the FEL-FES controller had a problem in learning of the inverse dynamics model (IDM) in some cases. In this paper, methods of applying the FEL to FES control were examined in controlling 1-DOF movement of the wrist joint stimulating 2 muscles through computer simulation under several control conditions with several subject models. The problems in applying FEL to FES controller were suggested to be in restricting stimulation intensity to positive values between the minimum and the maximum intensities and in the case of very small output values of the IDM. Learning of the IDM was greatly improved by considering the IDM output range with setting the minimum ANN output value in calculating ANN connection weight change.

  7. Evolutional Optimization on Material Ordering and Inventory Control of Supply Chain through Incentive Scheme

    Science.gov (United States)

    Prasertwattana, Kanit; Shimizu, Yoshiaki; Chiadamrong, Navee

    This paper studied the material ordering and inventory control of supply chain systems. The effect of controlling policies is analyzed under three different configurations of the supply chain systems, and the formulated problem has been solved by using an evolutional optimization method known as Differential Evolution (DE). The numerical results show that the coordinating policy with the incentive scheme outperforms the other policies and can improve the performance of the overall system as well as all members under the concept of supply chain management.

  8. Two hybrid ARQ error control schemes for near Earth satellite communications

    Science.gov (United States)

    Lin, S.

    1986-01-01

    Two hybrid Automatic Repeat Request (ARQ) error control schemes are proposed for NASA near Earth satellite communications. Both schemes are adaptive in nature, and employ cascaded codes to achieve both high reliability and throughput efficiency for high data rate file transfer.

  9. Design and Simulation of a Distributed Control Scheme for Inter-Destination Media Synchronization

    NARCIS (Netherlands)

    Montagud, M.; Boronat, F.; Stokking, H.M.

    2013-01-01

    Inter-Destination Multimedia Synchronization (IDMS) is a key requirement to enable satisfying group shared media experiences. This paper presents the design and simulation of a Distributed Control Scheme (DCS) for IDMS. In this scheme, geographically dispersed receivers exchange (multicast) RTCP

  10. Integration of Fault Detection and Isolation with Control Using Neuro-fuzzy Scheme

    Directory of Open Access Journals (Sweden)

    A. Asokan

    2009-10-01

    Full Text Available In this paper an algorithms is developed for fault diagnosis and fault tolerant control strategy for nonlinear systems subjected to an unknown time-varying fault. At first, the design of fault diagnosis scheme is performed using model based fault detection technique. The neuro-fuzzy chi-square scheme is applied for fault detection and isolation. The fault magnitude and time of occurrence of fault is obtained through neuro-fuzzy chi-square scheme. The estimated magnitude of the fault magnitude is normalized and used by the feed-forward control algorithm to make appropriate changes in the manipulated variable to keep the controlled variable near its set value. The feed-forward controller acts along with feed-back controller to control the multivariable system. The performance of the proposed scheme is applied to a three- tank process for various types of fault inputs to show the effectiveness of the proposed approach.

  11. Regulation control and energy management scheme for wireless power transfer

    Science.gov (United States)

    Miller, John M.

    2015-12-29

    Power transfer rate at a charging facility can be maximized by employing a feedback scheme. The state of charge (SOC) and temperature of the regenerative energy storage system (RESS) pack of a vehicle is monitored to determine the load due to the RESS pack. An optimal frequency that cancels the imaginary component of the input impedance for the output signal from a grid converter is calculated from the load of the RESS pack, and a frequency offset f* is made to the nominal frequency f.sub.0 of the grid converter output based on the resonance frequency of a magnetically coupled circuit. The optimal frequency can maximize the efficiency of the power transfer. Further, an optimal grid converter duty ratio d* can be derived from the charge rate of the RESS pack. The grid converter duty ratio d* regulates wireless power transfer (WPT) power level.

  12. Hopf Bifurcation Control in a FAST TCP and RED Model via Multiple Control Schemes

    Directory of Open Access Journals (Sweden)

    Dawei Ding

    2016-01-01

    Full Text Available We focus on the Hopf bifurcation control problem of a FAST TCP model with RED gateway. The system gain parameter is chosen as the bifurcation parameter, and the stable region and stability condition of the congestion control model are given by use of the linear stability analysis. When the system gain passes through a critical value, the system loses the stability and Hopf bifurcation occurs. Considering the negative influence caused by Hopf bifurcation, we apply state feedback controller, hybrid controller, and time-delay feedback controller to postpone the onset of undesirable Hopf bifurcation. Numerical simulations show that the hybrid controller is the most sensitive method to delay the Hopf bifurcation with identical parameter conditions. However, nonlinear state feedback control and time-delay feedback control schemes have larger control parameter range in the Internet congestion control system with FAST TCP and RED gateway. Therefore, we can choose proper control method based on practical situation including unknown conditions or parameter requirements. This paper plays an important role in setting guiding system parameters for controlling the FAST TCP and RED model.

  13. Adaptive Test Schemes for Control of Paratuberculosis in Dairy Cows.

    Directory of Open Access Journals (Sweden)

    Carsten Kirkeby

    Full Text Available Paratuberculosis is a chronic infection that in dairy cattle causes reduced milk yield, weight loss, and ultimately fatal diarrhea. Subclinical animals can excrete bacteria (Mycobacterium avium ssp. paratuberculosis, MAP in feces and infect other animals. Farmers identify the infectious animals through a variety of test-strategies, but are challenged by the lack of perfect tests. Frequent testing increases the sensitivity but the costs of testing are a cause of concern for farmers. Here, we used a herd simulation model using milk ELISA tests to evaluate the epidemiological and economic consequences of continuously adapting the sampling interval in response to the estimated true prevalence in the herd. The key results were that the true prevalence was greatly affected by the hygiene level and to some extent by the test-frequency. Furthermore, the choice of prevalence that will be tolerated in a control scenario had a major impact on the true prevalence in the normal hygiene setting, but less so when the hygiene was poor. The net revenue is not greatly affected by the test-strategy, because of the general variation in net revenues between farms. An exception to this is the low hygiene herd, where frequent testing results in lower revenue. When we look at the probability of eradication, then it is correlated with the testing frequency and the target prevalence during the control phase. The probability of eradication is low in the low hygiene herd, and a test-and-cull strategy should probably not be the primary strategy in this herd. Based on this study we suggest that, in order to control MAP, the standard Danish dairy farm should use an adaptive strategy where a short sampling interval of three months is used when the estimated true prevalence is above 1%, and otherwise use a long sampling interval of one year.

  14. Adaptive Test Schemes for Control of Paratuberculosis in Dairy Cows.

    Science.gov (United States)

    Kirkeby, Carsten; Græsbøll, Kaare; Nielsen, Søren Saxmose; Christiansen, Lasse Engbo; Toft, Nils; Halasa, Tariq

    2016-01-01

    Paratuberculosis is a chronic infection that in dairy cattle causes reduced milk yield, weight loss, and ultimately fatal diarrhea. Subclinical animals can excrete bacteria (Mycobacterium avium ssp. paratuberculosis, MAP) in feces and infect other animals. Farmers identify the infectious animals through a variety of test-strategies, but are challenged by the lack of perfect tests. Frequent testing increases the sensitivity but the costs of testing are a cause of concern for farmers. Here, we used a herd simulation model using milk ELISA tests to evaluate the epidemiological and economic consequences of continuously adapting the sampling interval in response to the estimated true prevalence in the herd. The key results were that the true prevalence was greatly affected by the hygiene level and to some extent by the test-frequency. Furthermore, the choice of prevalence that will be tolerated in a control scenario had a major impact on the true prevalence in the normal hygiene setting, but less so when the hygiene was poor. The net revenue is not greatly affected by the test-strategy, because of the general variation in net revenues between farms. An exception to this is the low hygiene herd, where frequent testing results in lower revenue. When we look at the probability of eradication, then it is correlated with the testing frequency and the target prevalence during the control phase. The probability of eradication is low in the low hygiene herd, and a test-and-cull strategy should probably not be the primary strategy in this herd. Based on this study we suggest that, in order to control MAP, the standard Danish dairy farm should use an adaptive strategy where a short sampling interval of three months is used when the estimated true prevalence is above 1%, and otherwise use a long sampling interval of one year.

  15. A Comparison between Voltage and Reactive Power Feedback Schemes of DFIGs for Inter-Area Oscillation Damping Control

    Directory of Open Access Journals (Sweden)

    Kai Liao

    2017-08-01

    Full Text Available Reactive power modulation of wind power plants is an effective way to damp inter-area oscillation in wind power penetrated power systems. For doubly fed induction generator (DFIG based wind farms, there are two different ways to achieve reactive power modulation: one is via reactive power feedback control, and the other method is via voltage feedback control. While both of the control schemes are feasible, their effectiveness may differ, and there has not been a systematic comparison between them. This paper investigates the differences between these two feedback schemes for inter-area oscillation damping control. The principles of utilizing DFIG for damping control is introduced at first. Then, analytical techniques including the frequency domain analysis, μ -analysis and time domain analysis are used to systematically study the performance of the two control schemes against inter-area oscillation. The robustness of the control schemes with respect to the variety of system operation points is also studied. The results from this paper can provide an insight into the understatement of DFIG reactive modulation against oscillation and guidance for controller design.

  16. Control charts for location based on different sampling schemes

    NARCIS (Netherlands)

    Mehmood, R.; Riaz, M.; Does, R.J.M.M.

    2013-01-01

    Control charts are the most important statistical process control tool for monitoring variations in a process. A number of articles are available in the literature for the X̄ control chart based on simple random sampling, ranked set sampling, median-ranked set sampling (MRSS), extreme-ranked set

  17. A fuzzy robust control scheme for vibration suppression of a nonlinear electromagnetic-actuated flexible system

    Science.gov (United States)

    Tavakolpour-Saleh, A. R.; Haddad, M. A.

    2017-03-01

    In this paper, a novel robust vibration control scheme, namely, one degree-of-freedom fuzzy active force control (1DOF-FAFC) is applied to a nonlinear electromagnetic-actuated flexible plate system. First, the flexible plate with clamped-free-clamped-free (CFCF) boundary conditions is modeled and simulated. Then, the validity of the simulation platform is evaluated through experiment. A nonlinear electromagnetic actuator is developed and experimentally modeled through a parametric system identification scheme. Next, the obtained nonlinear model of the actuator is applied to the simulation platform and performance of the proposed control technique in suppressing unwanted vibrations is investigated via simulation. A fuzzy controller is applied to the robust 1DOF control scheme to tune the controller gain using acceleration feedback. Consequently, an intelligent self-tuning vibration control strategy based on an inexpensive acceleration sensor is proposed in the paper. Furthermore, it is demonstrated that the proposed acceleration-based control technique owns the benefits of the conventional velocity feedback controllers. Finally, an experimental rig is developed to investigate the effectiveness of the 1DOF-FAFC scheme. It is found that the first, second, and third resonant modes of the flexible system are attenuated up to 74%, 81%, and 90% respectively through which the effectiveness of the proposed control scheme is affirmed.

  18. A Robust Control Scheme for Medium-Voltage-Level DVR Implementation

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Loh, Poh Chiang; Li, Yun Wei

    2007-01-01

    of Hinfin controller weighting function selection, inner current loop tuning, and system disturbance rejection capability is presented. Finally, the designed control scheme is extensively tested on a laboratory 10-kV MV-level DVR system with varying voltage sag (balanced and unbalanced) and loading (linear......In this paper, a robust control scheme with an outer Hinfin voltage control loop and an inner current control loop is designed and implemented on a medium-voltage (MV)-level dynamic voltage restorer (DVR) system. Through a simple selection of weighting functions, the synthesized Hinfin controller....../nonlinear load and induction motor load) conditions. It is shown that the proposed control scheme is effective in both balanced and unbalanced sag compensation and load disturbance rejection, as its robustness is explicitly specified....

  19. Implementation of a Cross-Layer Sensing Medium-Access Control Scheme.

    Science.gov (United States)

    Su, Yishan; Fu, Xiaomei; Han, Guangyao; Xu, Naishen; Jin, Zhigang

    2017-04-10

    In this paper, compressed sensing (CS) theory is utilized in a medium-access control (MAC) scheme for wireless sensor networks (WSNs). We propose a new, cross-layer compressed sensing medium-access control (CL CS-MAC) scheme, combining the physical layer and data link layer, where the wireless transmission in physical layer is considered as a compress process of requested packets in a data link layer according to compressed sensing (CS) theory. We first introduced using compressive complex requests to identify the exact active sensor nodes, which makes the scheme more efficient. Moreover, because the reconstruction process is executed in a complex field of a physical layer, where no bit and frame synchronizations are needed, the asynchronous and random requests scheme can be implemented without synchronization payload. We set up a testbed based on software-defined radio (SDR) to implement the proposed CL CS-MAC scheme practically and to demonstrate the validation. For large-scale WSNs, the simulation results show that the proposed CL CS-MAC scheme provides higher throughput and robustness than the carrier sense multiple access (CSMA) and compressed sensing medium-access control (CS-MAC) schemes.

  20. A new control scheme for PID load frequency controller of single-area and multi-area power systems.

    Science.gov (United States)

    Padhan, Dola Gobinda; Majhi, Somanath

    2013-03-01

    A new control structure with a tuning method to design a PID load frequency controller for power systems is presented. Initially, the controller is designed for single area power system, then it is extended to multi-area case. The controller parameters are obtained by expanding controller transfer function using Laurent series. Relay based identification technique is adopted to estimate power system dynamics. Robustness studies on stability and performance are provided, with respect to uncertainties in the plant parameters. The proposed scheme ensures that overall system remains asymptotically stable for all bounded uncertainties and for system oscillations. Simulation results show the feasibility of the approach and the proposed method improves the load disturbance rejection performance significantly even in the presence of the uncertainties in plant parameters. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

  1. An Optimal Control Scheme to Minimize Loads in Wind Farms

    DEFF Research Database (Denmark)

    Soleimanzadeh, Maryam; Wisniewski, Rafal

    2012-01-01

    This work presents a control algorithm for wind farms that optimizes the power production of the farm and helps to increase the lifetime of wind turbines components. The control algorithm is a centralized approach, and it determines the power reference signals for individual wind turbines...... such that the structural loads of the wind turbines in low frequencies are reduced. The controller is relatively easy to implement on a wind farm, and in here the results of simulating the controller on a small wind farm is presented....

  2. A hybrid iterative scheme for optimal control problems governed by ...

    African Journals Online (AJOL)

    MRT

    obtaining approximate solutions of optimal control problems governed by some Fredholm integral equations. By some numerical ... Trace of numerical approaches in optimal control problems can be found in many applications and academic literatures. ...... Progress In Electromagnetics Research 78: 361–376. Ghasemi, M.

  3. Analysis of Contracting Processes, Internal Controls, and Procurement Fraud Schemes

    Science.gov (United States)

    2013-06-01

    of the Treadway Commission ( COSO ). (1992). Internal control-integrated framework . Retrieved from http://www.coso.org Competition in Contracting...United States COR Contracting Officer Representative COSO Committee of Sponsoring Organizations DAU Defense Acquisition University DAWIA Defense...adopted from the Committee of Sponsoring Organizations of the Treadway Commission ( COSO ) (1992). There are five components: control environment, risk

  4. Algorithms for Optimal Model Distributions in Adaptive Switching Control Schemes

    NARCIS (Netherlands)

    Ghosh, D.; Baldi, S.

    2016-01-01

    Several multiple model adaptive control architectures have been proposed in the literature. Despite many advances in theory, the crucial question of how to synthesize the pairs model/controller in a structurally optimal way is to a large extent not addressed. In particular, it is not clear how to

  5. Reliable, Efficient, and Power Optimized Control-Channel Selection Scheme for Cognitive Radio Networks

    Directory of Open Access Journals (Sweden)

    Saleem Aslam

    2013-01-01

    Full Text Available This paper presents a centralized control-channel selection scheme for cognitive radio networks (CRNs by exploiting the variation in the spectrum across capacity, occupancy, and error rate. We address the fundamental challenges in the design of the control-channel for CRNs: (1 random licensed users (LUs activity and (2 the economical and vulnerability concerns for a dedicated control-channel. We develop a knapsack problem (KP based reliable, efficient, and power optimized (REPO control-channel selection scheme with an optimal data rate, bit error rate (BER, and idle time. Moreover, we introduce the concept of the backup channels in the context of control-channel selection, which assists the CRs to quickly move on to the next stable channel in order to cater for the sudden appearance of LUs. Based on the KP and its dynamic programming solution, simulation results show that the proposed scheme is highly adaptable and resilient to random LU activity. The REPO scheme reduces collisions with the LUs, minimizes the alternate channel selection time, and reduces the bit error rate (BER. Moreover, it reduces the power consumed during channel switching and provides a performance, that is, competitive with those schemes that are using a static control-channel for the management of control traffic in CRNs.

  6. The Ponzi Scheme: An exploratory study of the victim.

    Directory of Open Access Journals (Sweden)

    Irene Parejo-Pizarro

    2017-02-01

    Full Text Available Objective: The general aim of this study was to explore the victimization process of the so-called “pyramid scheme fraud”. Specifically the causal agents of this fraud and the consequent damage were analyzed as well as the victims’ different responses. Method: The sample comprised 14 victims of the fraud (12 direct victims and 2 indirect victims aged 47-87 years old. Semi-structured interviews were conducted in depth, comprising a total of 36 questions. Results: The factors involved in the fraud appear simultaneously, these factors being economic and trust elements. Considering the reactions to this type of scam, the bipolar factor of earning vs. losing money seems to play a basic role in those victims who decide to invest. This way two different behaviors may emerge: on the one hand, the legitimation of this “business” and, on the other hand, the rejection of it. Conclusions: There were no significant differences between the factors that influence people to invest and maintain their investment in the pyramid scheme fraud. However, some differences have been observed with respect to the reactions against the scam. Future studies should be based on bigger samples, which could lead to the acquisition of a personality profile of the victims. In addition, two subgroups might be considered: Those who make money and those who lose money.

  7. Pre-Allocation Based Flow Control Scheme for Networks-On-Chip

    Science.gov (United States)

    Lin, Shijun; Su, Li; Su, Haibo; Jin, Depeng; Zeng, Lieguang

    Based on the traffic predictability characteristic of Networks-on-Chip (NoC), we propose a pre-allocation based flow control scheme to improve the performance of NoC. In this scheme, routes are pre-allocated and the injection rates of all routes are regulated at the traffic sources according to the average available bandwidths in the links. Then, the number of packets in the network is decreased and thus, the congestion probability is reduced and the communication performance is improved. Simulation results show that this scheme greatly increases the throughput and cuts down the average latency with little area and energy overhead, compared with the switch-to-switch flow control scheme.

  8. Research on a New Control Scheme of Photovoltaic Grid Power Generation System

    Directory of Open Access Journals (Sweden)

    Dong-Hui Li

    2014-01-01

    Full Text Available A new type of photovoltaic grid power generation system control scheme to solve the problems of the conventional photovoltaic grid power generation systems is presented. To aim at the oscillation and misjudgment of traditional perturbation observation method, an improved perturbation observation method comparing to the next moment power is proposed, combining with BOOST step-up circuit to realize the maximum power tracking. To counter the harmonic pollution problem in photovoltaic grid power generation system, the deadbeat control scheme in fundamental wave synchronous frequency rotating coordinate system of power grid is presented. A parameter optimization scheme based on positive feedback of active frequency shift island detection to solve the problems like the nondetection zone due to the import of disturbance in traditional island detection method is proposed. Finally, the results in simulation environment by MATLAB/Simulink simulation and experiment environment verify the validity and superiority of the proposed scheme.

  9. Performance analysis of joint diversity combining, adaptive modulation, and power control schemes

    KAUST Repository

    Qaraqe, Khalid A.

    2011-01-01

    Adaptive modulation and diversity combining represent very important adaptive solutions for future generations of wireless communication systems. Indeed, in order to improve the performance and the efficiency of these systems, these two techniques have been recently used jointly in new schemes named joint adaptive modulation and diversity combining (JAMDC) schemes. Considering the problem of finding low hardware complexity, bandwidth-efficient, and processing-power efficient transmission schemes for a downlink scenario and capitalizing on some of these recently proposed JAMDC schemes, we propose and analyze in this paper three joint adaptive modulation, diversity combining, and power control (JAMDCPC) schemes where a constant-power variable-rate adaptive modulation technique is used with an adaptive diversity combining scheme and a common power control process. More specifically, the modulation constellation size, the number of combined diversity paths, and the needed power level are jointly determined to achieve the highest spectral efficiency with the lowest possible processing power consumption quantified in terms of the average number of combined paths, given the fading channel conditions and the required bit error rate (BER) performance. In this paper, the performance of these three JAMDCPC schemes is analyzed in terms of their spectral efficiency, processing power consumption, and error-rate performance. Selected numerical examples show that these schemes considerably increase the spectral efficiency of the existing JAMDC schemes with a slight increase in the average number of combined paths for the low signal-to-noise ratio range while maintaining compliance with the BER performance and a low radiated power which yields to a substantial decrease in interference to co-existing users and systems. © 2011 IEEE.

  10. A low order adaptive control scheme for hydraulic servo systems

    DEFF Research Database (Denmark)

    Andersen, Torben Ole; Pedersen, Henrik Clemmensen; Bech, Michael Møller

    2015-01-01

    This paper deals with high-performance position control of hydraulics servo systems in general. The hydraulic servo system used is a two link robotic manipulator actuated by two hydraulic servo cylinders. A non-linear model of the hydraulic system and a Newton-Euler based model of the mechanical...

  11. Control and management scheme in a DWDM EPON

    NARCIS (Netherlands)

    Roy, R.; Manhoudt, Gert; Roeloffzen, C.G.H.; van Etten, Wim

    2006-01-01

    Passive Optical Networks (PONs) are a preferred architecture for distribution of bandwidth in the access network. The BSIK Freeband Broadband Photonics Project(BBP) looks at the design of a flexible DWDM PON which can be used to increase the bandwidth provided to the user. We present a control and

  12. A novel and efficient user access control scheme for wireless body area sensor networks

    Directory of Open Access Journals (Sweden)

    Santanu Chatterjee

    2014-07-01

    Full Text Available Wireless body area networks (WBANs can be applied to provide healthcare and patient monitoring. However, patient privacy can be vulnerable in a WBAN unless security is considered. Access to authorized users for the correct information and resources for different services can be provided with the help of efficient user access control mechanisms. This paper proposes a new user access control scheme for a WBAN. The proposed scheme makes use of a group-based user access ID, an access privilege mask, and a password. An elliptic curve cryptography-based public key cryptosystem is used to ensure that a particular legitimate user can only access the information for which he/she is authorized. We show that our scheme performs better than previously existing user access control schemes. Through a security analysis, we show that our scheme is secure against possible known attacks. Furthermore, through a formal security verification using the AVISPA (Automated Validation of Internet Security Protocols and Applications tool, we show that our scheme is also secure against passive and active attacks.

  13. Parameter Identification and Control Scheme for Monitoring Automatic Thickness Control System with Measurement Delay

    Directory of Open Access Journals (Sweden)

    Xu Yang

    2017-01-01

    Full Text Available The thickness of the steel strip is an important indicator of the overall strip quality. Deviations in thickness are primarily controlled using the automatic gauge control (AGC system of each rolling stand. At the last stand, the monitoring AGC system is usually used, where the deviations in thickness can be directly measured by the X-ray thickness gauge device and used as the input to the AGC system. However, due to the physical distance between the thickness detection device and the rolling stand, time delay is unavoidably present in the thickness control loop, which can affect control performance and lead to system oscillations. Furthermore, the parameters of the system can change due to perturbations from external disturbances. Therefore, this paper proposes an identification and control scheme for monitoring AGC system that can handle time delay and parameter uncertainty. The cross-correlation function is used to estimate the time delay of the system, while the system parameters are identified using a recursive least squares method. The time delay and parameter estimates are then further refined using the Levenberg-Marquardt algorithm, so as to provide the most accurate parameter estimates for the complete system. Simulation results show that, compared with the standard Proportion Integration Differentiation (PID controller approach, the proposed approach is not affected by changes in the time delay and parameter uncertainties.

  14. Study on optimized upwind schemes for computational areoacoustics and extension of a fully conservative Chimera to finite difference schemes

    Science.gov (United States)

    Chen, Rangfu

    A computational methodology has been developed in the first part of the thesis for the simulations of acoustic radiation, propagation and reflection. The developed methodology is high order accurate, uses less grid points per wave length comparing to standard high order accurate numerical methods, and automatically damps out spurious short waves. Furthermore, the methodology can be applied to acoustic problems in the presence of objects with curved geometries. To achieve these results, high order accurate optimized upwind schemes, which are applied to discretize spatial derivatives on interior grid points, have been developed. High order accurate optimized one- side biased schemes, which are only applied to discretize the spatial derivatives on grid points near computational boundaries, have also been constructed. The developed schemes are combined with a time difference scheme to fully discretize acoustic field equations in multi- dimension in arbitrary curvilinear coordinates. Numerical boundary conditions are investigated and intuitively illustrated. Applications of the developed methodology to a sequence of one-dimensional and multi-dimensional acoustic problems are performed. The numerical results have validated the developed methodology and demonstrated advantages of the methodology over central-difference Dispersion-Relation-Preserving method. Numerical results have also shown that the optimized upwind schemes minimize not only the dissipation error but also the dissipation error, while retaining the numerical stability. The second part of the thesis deals with a fully conservative Chimera methodology. The fully conservative Chimera was originally developed based on a finite volume approach. A finite difference scheme is shown to be identical to a finite volume scheme with proper definition of control volumes and metrics. The fully conservative Chimera has been successfully extended to finite difference schemes for viscous flows including turbulence models

  15. A unified numerical scheme for linear-quadratic optimal control problems with joint control and state constraints

    NARCIS (Netherlands)

    Han, Lanshan; Camlibel, M. Kanat; Pang, Jong-Shi; Heemels, W. P. Maurice H.

    2012-01-01

    This paper presents a numerical scheme for solving the continuous-time convex linear-quadratic (LQ) optimal control problem with mixed polyhedral state and control constraints. Unifying a discretization of this optimal control problem as often employed in model predictive control and that obtained

  16. PLS-based memory control scheme for enhanced process monitoring

    KAUST Repository

    Harrou, Fouzi

    2017-01-20

    Fault detection is important for safe operation of various modern engineering systems. Partial least square (PLS) has been widely used in monitoring highly correlated process variables. Conventional PLS-based methods, nevertheless, often fail to detect incipient faults. In this paper, we develop new PLS-based monitoring chart, combining PLS with multivariate memory control chart, the multivariate exponentially weighted moving average (MEWMA) monitoring chart. The MEWMA are sensitive to incipient faults in the process mean, which significantly improves the performance of PLS methods and widen their applicability in practice. Using simulated distillation column data, we demonstrate that the proposed PLS-based MEWMA control chart is more effective in detecting incipient fault in the mean of the multivariate process variables, and outperform the conventional PLS-based monitoring charts.

  17. Integrated Backstepping Design of Missile Guidance andControl with Time delay Adaptive Scheme

    Science.gov (United States)

    2016-03-30

    Guidance and Control with Time-delay Adaptive Scheme Seong-Min Hong 1 , Min-Guk Seo 1 , Chang-Hun Lee 2 and Min-Jea Tahk 1 1 Department...engagement kinematics are merged. Control input for the overall system is derived by backstepping approach. The stability of control logic is proved...estimated by using a time-delay adaptive control law. The performance of designed controller is investigated by numerical simulation. Keywords

  18. New scheme of variable optical buffer for IP packets used in access control of HORNET

    Science.gov (United States)

    Fang, Nian; Wang, Lutang; Huang, Zhaoming

    2002-09-01

    A new scheme of variable optical buffer for IP packets is reported. It may be used in access control of HORNET (Hybrid Optoelectronic Ring NETwork), to avoid collision of added packet and the packet already on the ring and improve the loss ratio of the packets. In this scheme, a new multi-wavelength fiber loop memory technique is employed. This architecture uses the wavelength converter (WC) to specify the packets delay and wavelength conversion is accomplished by the technique of four-wave-mixing (FWM) with a semiconductor optical amplifier (SOA). The range of delay is 10 to 9990 bytes periods. First, architecture, operation principle, characteristics and applications of this scheme of variable optical buffer are introduced. Next, a new unslotted CSMA/CA MAC scheme based on the variable optical buffer is briefly introduced too. Finally, the simulation results are presented.

  19. A Novel, Automatic Quality Control Scheme for Real Time Image Transmission

    Directory of Open Access Journals (Sweden)

    S. Ramachandran

    2002-01-01

    Full Text Available A novel scheme to compute energy on-the-fly and thereby control the quality of the image frames dynamically is presented along with its FPGA implementation. This scheme is suitable for incorporation in image compression systems such as video encoders. In this new scheme, processing is automatically stopped when the desired quality is achieved for the image being processed by using a concept called pruning. Pruning also increases the processing speed by a factor of more than two when compared to the conventional method of processing without pruning. An MPEG-2 encoder implemented using this scheme is capable of processing good quality monochrome and color images of sizes up to 1024 × 768 pixels at the rate of 42 and 28 frames per second, respectively, with a compression ratio of over 17:1. The encoder is also capable of working in the fixed pruning level mode with user programmable features.

  20. A circuit scheme to control current surge for RFID-NVM pumps

    Energy Technology Data Exchange (ETDEWEB)

    Li Ming; Kang Jinfeng; Wang Yangyuan [Institute of Microelectronics, Peking University, Beijing 100871 (China); Yang Liwu, E-mail: prettynecess@163.co [Semiconductor Manufacturing International Corporation, Shanghai 201203 (China)

    2010-02-15

    This paper presents a new circuit scheme to control the current surge in the boosting phase of an radio frequency idenfication-nonvolative memory pump. By introducing a circuit block consisting of a current reference and a current mirror, the new circuit scheme can keep the period-average current of the pump constantly below the desired level, for example, 2.5 {mu}A. Therefore, it can prevent the rectified supply of the RFID tag IC from collapsing in the boosting phase of the pump. The presented scheme could effectively reduce the voltage drop on the rectified supply from more than 50% to even zero, but could cost less area. Moreover, an analytical expression to calculate the boosting time of a pump in the new scheme is developed. (semiconductor integrated circuits)

  1. Experimental bifurcation analysis of an impact oscillator - Tuning a non-invasive control scheme

    DEFF Research Database (Denmark)

    Bureau, Emil; Schilder, Frank; Santos, Ilmar

    2013-01-01

    We investigate a non-invasive, locally stabilizing control scheme necessary for an experimental bifurcation analysis. Our test-rig comprises a harmonically forced impact oscillator with hardening spring nonlinearity controlled by electromagnetic actuators, and serves as a prototype for electromag...

  2. Lyapunov-Based Control Scheme for Single-Phase Grid-Connected PV Central Inverters

    NARCIS (Netherlands)

    Meza, C.; Biel, D.; Jeltsema, D.; Scherpen, J. M. A.

    A Lyapunov-based control scheme for single-phase single-stage grid-connected photovoltaic central inverters is presented. Besides rendering the closed-loop system globally stable, the designed controller is able to deal with the system uncertainty that depends on the solar irradiance. A laboratory

  3. Study on livestock management scheme considering national environmental capacity

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jee Yong; Shin, Eun Seong [Korea Environment Institute, Seoul (Korea)

    1999-12-01

    In 'Our Common Future' reported in WCED (World Commission on Environment and Development) in 1983, a sustainable development is defined as 'development that meets the needs of the present without compromising the ability of future generations to meet their own needs'. The environmental problem since the 1992 Rio Summit has focused on sustainability. Furthermore agriculture industry also promotes a sustainable agriculture in worldwide. The most focused one among sustainable agriculture is an environmental friendly agriculture including organic agriculture since soil has been acidified due to the abuse of chemical fertilizer for mass production. In this study, it represents an appropriate management scheme for livestock suitable to Korean land by assessing admitted capacity and water quality pollution. 32 refs., 11 figs., 77 tabs.

  4. Optimization of a Traffic Control Scheme for a Post-Disaster Urban Road Network

    Directory of Open Access Journals (Sweden)

    Zengzhen Shao

    2017-12-01

    Full Text Available Traffic control of urban road networks during emergency rescues is conducive to rapid rescue in the affected areas. However, excessive control will lead to negative impacts on the normal traffic order. We propose a novel model to optimize the traffic control scheme during the post-disaster emergency rescue period named PD-TCM (post-disaster traffic control model. In this model, the vertex and edge betweenness indexes of urban road networks are introduced to evaluate the controllability of the road sections. The gravity field model is also used to adjust the travel time function of different road sections in the control and diverging domains. Experimental results demonstrate that the proposed model can obtain the optimal traffic control scheme efficiently, which gives it the ability to meet the demand of emergency rescues as well as reducing the disturbances caused by controls.

  5. Voltage Control Scheme with Distributed Generation and Grid Connected Converter in a DC Microgrid

    Directory of Open Access Journals (Sweden)

    Jong-Chan Choi

    2014-10-01

    Full Text Available Direct Current (DC microgrids are expected to become larger due to the rapid growth of DC energy sources and power loads. As the scale of the system expends, the importance of voltage control will be increased to operate power systems stably. Many studies have been performed on voltage control methods in a DC microgrid, but most of them focused only on a small scale microgrid, such as a building microgrid. Therefore, a new control method is needed for a middle or large scale DC microgrid. This paper analyzes voltage drop problems in a large DC microgrid and proposes a cooperative voltage control scheme with a distributed generator (DG and a grid connected converter (GCC. For the voltage control with DGs, their location and capacity should be considered for economic operation in the systems. Accordingly, an optimal DG allocation algorithm is proposed to minimize the capacity of a DG for voltage control in DC microgrids. The proposed methods are verified with typical load types by a simulation using MATLAB and PSCAD/EMTDC.

  6. Autonomous Distributed Congestion Control Scheme in WCDMA Network

    Science.gov (United States)

    Ahmad, Hafiz Farooq; Suguri, Hiroki; Choudhary, Muhammad Qaisar; Hassan, Ammar; Liaqat, Ali; Khan, Muhammad Umer

    Wireless technology has become widely popular and an important means of communication. A key issue in delivering wireless services is the problem of congestion which has an adverse impact on the Quality of Service (QoS), especially timeliness. Although a lot of work has been done in the context of RRM (Radio Resource Management), the deliverance of quality service to the end user still remains a challenge. Therefore there is need for a system that provides real-time services to the users through high assurance. We propose an intelligent agent-based approach to guarantee a predefined Service Level Agreement (SLA) with heterogeneous user requirements for appropriate bandwidth allocation in QoS sensitive cellular networks. The proposed system architecture exploits Case Based Reasoning (CBR) technique to handle RRM process of congestion management. The system accomplishes predefined SLA through the use of Retrieval and Adaptation Algorithm based on CBR case library. The proposed intelligent agent architecture gives autonomy to Radio Network Controller (RNC) or Base Station (BS) in accepting, rejecting or buffering a connection request to manage system bandwidth. Instead of simply blocking the connection request as congestion hits the system, different buffering durations are allocated to diverse classes of users based on their SLA. This increases the opportunity of connection establishment and reduces the call blocking rate extensively in changing environment. We carry out simulation of the proposed system that verifies efficient performance for congestion handling. The results also show built-in dynamism of our system to cater for variety of SLA requirements.

  7. HYBRID SYSTEM BASED FUZZY-PID CONTROL SCHEMES FOR UNPREDICTABLE PROCESS

    Directory of Open Access Journals (Sweden)

    M.K. Tan

    2011-07-01

    Full Text Available In general, the primary aim of polymerization industry is to enhance the process operation in order to obtain high quality and purity product. However, a sudden and large amount of heat will be released rapidly during the mixing process of two reactants, i.e. phenol and formalin due to its exothermic behavior. The unpredictable heat will cause deviation of process temperature and hence affect the quality of the product. Therefore, it is vital to control the process temperature during the polymerization. In the modern industry, fuzzy logic is commonly used to auto-tune PID controller to control the process temperature. However, this method needs an experienced operator to fine tune the fuzzy membership function and universe of discourse via trial and error approach. Hence, the setting of fuzzy inference system might not be accurate due to the human errors. Besides that, control of the process can be challenging due to the rapid changes in the plant parameters which will increase the process complexity. This paper proposes an optimization scheme using hybrid of Q-learning (QL and genetic algorithm (GA to optimize the fuzzy membership function in order to allow the conventional fuzzy-PID controller to control the process temperature more effectively. The performances of the proposed optimization scheme are compared with the existing fuzzy-PID scheme. The results show that the proposed optimization scheme is able to control the process temperature more effectively even if disturbance is introduced.

  8. A novel walking speed estimation scheme and its application to treadmill control for gait rehabilitation

    Directory of Open Access Journals (Sweden)

    Yoon Jungwon

    2012-08-01

    Full Text Available Abstract Background Virtual reality (VR technology along with treadmill training (TT can effectively provide goal-oriented practice and promote improved motor learning in patients with neurological disorders. Moreover, the VR + TT scheme may enhance cognitive engagement for more effective gait rehabilitation and greater transfer to over ground walking. For this purpose, we developed an individualized treadmill controller with a novel speed estimation scheme using swing foot velocity, which can enable user-driven treadmill walking (UDW to more closely simulate over ground walking (OGW during treadmill training. OGW involves a cyclic acceleration-deceleration profile of pelvic velocity that contrasts with typical treadmill-driven walking (TDW, which constrains a person to walk at a preset constant speed. In this study, we investigated the effects of the proposed speed adaptation controller by analyzing the gait kinematics of UDW and TDW, which were compared to those of OGW at three pre-determined velocities. Methods Ten healthy subjects were asked to walk in each mode (TDW, UDW, and OGW at three pre-determined speeds (0.5 m/s, 1.0 m/s, and 1.5 m/s with real time feedback provided through visual displays. Temporal-spatial gait data and 3D pelvic kinematics were analyzed and comparisons were made between UDW on a treadmill, TDW, and OGW. Results The observed step length, cadence, and walk ratio defined as the ratio of stride length to cadence were not significantly different between UDW and TDW. Additionally, the average magnitude of pelvic acceleration peak values along the anterior-posterior direction for each step and the associated standard deviations (variability were not significantly different between the two modalities. The differences between OGW and UDW and TDW were mainly in swing time and cadence, as have been reported previously. Also, step lengths between OGW and TDW were different for 0.5 m/s and 1.5 m/s gait velocities

  9. Physical control oriented model of large scale refrigerators to synthesize advanced control schemes. Design, validation, and first control results

    Science.gov (United States)

    Bonne, François; Alamir, Mazen; Bonnay, Patrick

    2014-01-01

    In this paper, a physical method to obtain control-oriented dynamical models of large scale cryogenic refrigerators is proposed, in order to synthesize model-based advanced control schemes. These schemes aim to replace classical user experience designed approaches usually based on many independent PI controllers. This is particularly useful in the case where cryoplants are submitted to large pulsed thermal loads, expected to take place in the cryogenic cooling systems of future fusion reactors such as the International Thermonuclear Experimental Reactor (ITER) or the Japan Torus-60 Super Advanced Fusion Experiment (JT-60SA). Advanced control schemes lead to a better perturbation immunity and rejection, to offer a safer utilization of cryoplants. The paper gives details on how basic components used in the field of large scale helium refrigeration (especially those present on the 400W @1.8K helium test facility at CEA-Grenoble) are modeled and assembled to obtain the complete dynamic description of controllable subsystems of the refrigerator (controllable subsystems are namely the Joule-Thompson Cycle, the Brayton Cycle, the Liquid Nitrogen Precooling Unit and the Warm Compression Station). The complete 400W @1.8K (in the 400W @4.4K configuration) helium test facility model is then validated against experimental data and the optimal control of both the Joule-Thompson valve and the turbine valve is proposed, to stabilize the plant under highly variable thermals loads. This work is partially supported through the European Fusion Development Agreement (EFDA) Goal Oriented Training Program, task agreement WP10-GOT-GIRO.

  10. An improved current control scheme for grid-connected DG unit based distribution system harmonic compensation

    DEFF Research Database (Denmark)

    He, Jinwei; Wei Li, Yun; Wang, Xiongfei

    2013-01-01

    In order to utilize DG unit interfacing converters to actively compensate distribution system harmonics, this paper proposes an enhanced current control approach. It seamlessly integrates system harmonic mitigation capabilities with the primary DG power generation function. As the proposed current...... controller has two well decoupled control branches to independently control fundamental and harmonic DG currents, phase-locked loops (PLL) and system harmonic component extractions can be avoided during system harmonic compensation. Moreover, a closed-loop power control scheme is also employed to derive...... the fundamental current reference. The proposed power control scheme effectively eliminates the impacts of steady-state fundamental current tracking errors in the DG units. Thus, an accurate power control is realized even when the harmonic compensation functions are activated. Experimental results from a single...

  11. The best prostate biopsy scheme is dictated by the gland volume: a monocentric study.

    Science.gov (United States)

    Dell'Atti, L

    2015-08-01

    Accuracy of biopsy scheme depends on different parameters. Prostate-specific antigen (PSA) level and digital rectal examination (DRE) influenced the detection rate and suggested the biopsy scheme to approach each patient. Another parameter is the prostate volume. Sampling accuracy tends to decrease progressively with an increasing prostate volume. We prospectively observed detection cancer rate in suspicious prostate cancer (PCa) and improved by applying a protocol biopsy according to prostate volume (PV). Clinical data and pathological features of these 1356 patients were analysed and included in this study. This protocol is a combined scheme that includes transrectal (TR) 12-core PBx (TR12PBx) for PV ≤ 30 cc, TR 14-core PBx (TR14PBx) for PV > 30 cc but scheme, in 198 (14.6%) through TR14PBx scheme and in 253 (18.6%) through TR18PBx scheme. The PCa detection rate was increased by 44% by adding two TZ cores (TR14PBx scheme). The TR18PBx scheme increased this rate by 21.7% vs. TR14PBx scheme. The diagnostic yield offered by TR18PBx was statistically significant compared to the detection rate offered by the TR14PBx scheme (p scheme diagnostic yield and those detected by the TR18PBx scheme (p = 0.362). The only PV parameter, in our opinion, can be significant in choosing the best biopsy scheme to approach in a first setting of biopsies increasing PCa detection rate.

  12. A New Pricing Scheme for Controlling Energy Storage Devices in Future Smart Grid

    Directory of Open Access Journals (Sweden)

    Jingwei Zhu

    2014-01-01

    Full Text Available Improvement of the overall efficiency of energy infrastructure is one of the main anticipated benefits of the deployment of smart grid technology. Advancement in energy storage technology and two-way communication in the electric network are indispensable components to achieve such a vision, while efficient pricing schemes and appropriate storage management are also essential. In this paper, we propose a universal pricing scheme which permits one to indirectly control the energy storage devices in the grid to achieve a more desirable aggregate demand profile that meets a particular target of the grid operator such as energy generation cost minimization and carbon emission reduction. Such a pricing scheme can potentially be applied to control the behavior of energy storage devices installed for integration of intermittent renewable energy sources that have permission to grid connection and will have broader applications as an increasing number of novel and low-cost energy storage technologies emerge.

  13. Nonlinear H∞ Optimal Control Scheme for an Underwater Vehicle with Regional Function Formulation

    Directory of Open Access Journals (Sweden)

    Zool H. Ismail

    2013-01-01

    Full Text Available A conventional region control technique cannot meet the demands for an accurate tracking performance in view of its inability to accommodate highly nonlinear system dynamics, imprecise hydrodynamic coefficients, and external disturbances. In this paper, a robust technique is presented for an Autonomous Underwater Vehicle (AUV with region tracking function. Within this control scheme, nonlinear H∞ and region based control schemes are used. A Lyapunov-like function is presented for stability analysis of the proposed control law. Numerical simulations are presented to demonstrate the performance of the proposed tracking control of the AUV. It is shown that the proposed control law is robust against parameter uncertainties, external disturbances, and nonlinearities and it leads to uniform ultimate boundedness of the region tracking error.

  14. An effective and secure key-management scheme for hierarchical access control in E-medicine system.

    Science.gov (United States)

    Odelu, Vanga; Das, Ashok Kumar; Goswami, Adrijit

    2013-04-01

    Recently several hierarchical access control schemes are proposed in the literature to provide security of e-medicine systems. However, most of them are either insecure against 'man-in-the-middle attack' or they require high storage and computational overheads. Wu and Chen proposed a key management method to solve dynamic access control problems in a user hierarchy based on hybrid cryptosystem. Though their scheme improves computational efficiency over Nikooghadam et al.'s approach, it suffers from large storage space for public parameters in public domain and computational inefficiency due to costly elliptic curve point multiplication. Recently, Nikooghadam and Zakerolhosseini showed that Wu-Chen's scheme is vulnerable to man-in-the-middle attack. In order to remedy this security weakness in Wu-Chen's scheme, they proposed a secure scheme which is again based on ECC (elliptic curve cryptography) and efficient one-way hash function. However, their scheme incurs huge computational cost for providing verification of public information in the public domain as their scheme uses ECC digital signature which is costly when compared to symmetric-key cryptosystem. In this paper, we propose an effective access control scheme in user hierarchy which is only based on symmetric-key cryptosystem and efficient one-way hash function. We show that our scheme reduces significantly the storage space for both public and private domains, and computational complexity when compared to Wu-Chen's scheme, Nikooghadam-Zakerolhosseini's scheme, and other related schemes. Through the informal and formal security analysis, we further show that our scheme is secure against different attacks and also man-in-the-middle attack. Moreover, dynamic access control problems in our scheme are also solved efficiently compared to other related schemes, making our scheme is much suitable for practical applications of e-medicine systems.

  15. Smart Salinity Management in Low-lying Deltaic Areas: A Model Predictive Control Scheme Applied to a Test Canal

    Science.gov (United States)

    Ekin Aydin, Boran; Rutten, Martine; Oude Essink, Gualbert H. P.; Delsman, Joost; Abraham, Edo

    2017-04-01

    Saline groundwater exfiltration to surface water increases surface water salinization and degrades the water quality in low-lying deltaic areas. As the use of surface water is less appropriate for agricultural, industrial and drinking water production due to salinization, freshwater diverted from a river is often utilised for flushing canals and ditches in these areas. Current water management strategies for flushing control in low-lying deltaic areas have to be revised to mitigate expected negative effects of climate change, sea level increase and decreasing fresh water availability. Model predictive control (MPC) is a powerful control method that is increasingly used for managing water systems. The explicit consideration of constraints and multi-objective management are important features of MPC. In this study, an MPC scheme is developed and tested for combined salinity and water level control of a ditch/water course. Saline groundwater exfiltration fluxes and salinities are modelled by applying the Rapid Saline Groundwater Exfiltration Model (RSGEM) and used as known disturbances for the MPC scheme. The developed control scheme is applied to a test canal using real data from a Dutch polder (Polders are low lying and artificially drained areas surrounded by dikes, with a controlled surface water level below M.S.L) which is affected by high saline groundwater exfiltration. This test demonstrates the performance of the controller for a real scenario. Simulation results show that MPC can increase the operational efficiency of flushing operations.

  16. OPTIMIZATION OF THE TEMPERATURE CONTROL SCHEME FOR ROLLER COMPACTED CONCRETE DAMS BASED ON FINITE ELEMENT AND SENSITIVITY ANALYSIS METHODS

    Directory of Open Access Journals (Sweden)

    Huawei Zhou

    2016-10-01

    Full Text Available Achieving an effective combination of various temperature control measures is critical for temperature control and crack prevention of concrete dams. This paper presents a procedure for optimizing the temperature control scheme of roller compacted concrete (RCC dams that couples the finite element method (FEM with a sensitivity analysis method. In this study, seven temperature control schemes are defined according to variations in three temperature control measures: concrete placement temperature, water-pipe cooling time, and thermal insulation layer thickness. FEM is employed to simulate the equivalent temperature field and temperature stress field obtained under each of the seven designed temperature control schemes for a typical overflow dam monolith based on the actual characteristics of a RCC dam located in southwestern China. A sensitivity analysis is subsequently conducted to investigate the degree of influence each of the three temperature control measures has on the temperature field and temperature tensile stress field of the dam. Results show that the placement temperature has a substantial influence on the maximum temperature and tensile stress of the dam, and that the placement temperature cannot exceed 15 °C. The water-pipe cooling time and thermal insulation layer thickness have little influence on the maximum temperature, but both demonstrate a substantial influence on the maximum tensile stress of the dam. The thermal insulation thickness is significant for reducing the probability of cracking as a result of high thermal stress, and the maximum tensile stress can be controlled under the specification limit with a thermal insulation layer thickness of 10 cm. Finally, an optimized temperature control scheme for crack prevention is obtained based on the analysis results.

  17. Design, implementation and testing of a fuzzy control scheme for laser welding

    NARCIS (Netherlands)

    Jauregui Becker, Juan Manuel; Aalderink, B.J.; Aalderink, Benno; Aarts, Ronald G.K.M.; Olde Benneker, Jeroen; Meijer, J.

    2008-01-01

    A fuzzy logic controller (FLC) scheme has been developed for laser welding. Process light emissions are measured and combined to determine the current status of the welding process. If the process is not in a desired welding state, the FLC will adapt the laser power. The FLC has been demonstrated

  18. Design and implementation of a topology control scheme for wireless mesh networks

    CSIR Research Space (South Africa)

    Mudali, P

    2009-09-01

    Full Text Available investigate the feasibility of power control in a popular WMN backbone device and design and evaluate an autonomous, light-weight TC scheme called PlainTC. An indoor test-bed evaluation shows that PlainTC is able to maintain network connectivity, achieve...

  19. A Reconfiguration Control Scheme for a Quadrotor Helicopter via Combined Multiple Models

    Directory of Open Access Journals (Sweden)

    Fuyang Chen

    2014-08-01

    Full Text Available In this paper, an optimal reconfiguration control scheme is proposed for a quadrotor helicopter with actuator faults via adaptive control and combined multiple models. The combined models set contains several fixed models, an adaptive model and a reinitialized adaptive model. The fixed models and the adaptive model can describe the failure system under different fault conditions. Moreover, the proposed reinitialized adaptive model refers to the closest model of the current system and can improve the speed of convergence effectively. In addition, the reference model is designed in consideration of an optimal control performance index and the principle of the minimum cost to achieve perfect tracking performance. Finally, some simulation results demonstrate the effectiveness of the proposed reconfiguration control scheme for faulty cases.

  20. A Power System Emergency Control Scheme in the Presence of High Wind Power Penetration

    DEFF Research Database (Denmark)

    Hoseinzadeh, Bakhtyar

    . Utilization of all of locally measurable variables, e.g. frequency, its rate of change, voltage drop, power flow direction under an integrated decentralized plan is done in this project, in order to improve the grid reliability. The proposed scheme benefits from a decentralized strategy, which reduces....... The load-frequency control as an ancillary service provided by renewable energy sources and load shedding as an emergency control should be localized. It means that the active power deficit should be compensated locally at vicinity of event location in order to avoid transferring the demanded active power...... from distant units to the incidence place. In this thesis, localization of both load-frequency control an load shedding are fulfilled using locally measured voltage drop data in the decentralized control strategy. The proposed load shedding scheme is coordinated with existing plant protection relays...

  1. Identity driven Capability based Access Control (ICAC) Scheme for the Internet of Things

    DEFF Research Database (Denmark)

    Mahalle, Parikshit N.; Anggorojati, Bayu; Prasad, Neeli R.

    2012-01-01

    Internet of Things (IoT) becomes discretionary part of everyday life. Scalability and manageability is daunting due to unbounded number of devices and services. Access control and authorization in IoT with least privilege is equally important to establish secure communication between multiple...... devices and services. In this paper, the concept of capability for access control is introduced where the identities of the involved devices are entrenched in the access capabilities. Identity driven capability based access control (ICAC) scheme presented in this paper helps to alleviate issues related...... to complexity and dynamics of device identities. ICAC is implemented for 802.11 and results shows that ICAC has less scalability issues and better performance analysis compared with other access control schemes. The ICAC evaluation by using security protocol verification tool shows that ICAC is secure against...

  2. Hierarchical Control Scheme for Improving Transient Voltage Recovery of a DFIG-Based WPP

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jinho; Muljadi, Eduard; Kang, Yong Cheol

    2015-06-05

    Modern grid codes require that wind power plants (WPPs) inject reactive power according to the voltage dip at a point of interconnection (POI). This requirement helps to support a POI voltage during a fault. However, if a fault is cleared, the POI and wind turbine generator (WTG) voltages are likely to exceed acceptable levels unless the WPP reduces the injected reactive power quickly. This might deteriorate the stability of a grid by allowing the disconnection of WTGs to avoid any damage. This paper proposes a hierarchical control scheme of a doubly-fed induction generator (DFIG)-based WPP. The proposed scheme aims to improve the reactive power injecting capability during the fault and suppress the overvoltage after the fault clearance. To achieve the former, an adaptive reactive power-to-voltage scheme is implemented in each DFIG controller so that a DFIG with a larger reactive power capability will inject more reactive power. To achieve the latter, a washout filter is used to capture a high frequency component contained in the WPP voltage, which is used to remove the accumulated values in the proportional-integral controllers. Test results indicate that the scheme successfully supports the grid voltage during the fault, and recovers WPP voltages without exceeding the limit after the fault clearance.

  3. STUDY ON SAFETY TECHNOLOGY SCHEME OF THE UNMANNED HELICOPTER

    Directory of Open Access Journals (Sweden)

    Z. Lin

    2013-08-01

    Full Text Available Nowadays the unmanned helicopter is widely used for its' unique strongpoint, however, the high failure rate of unmanned helicopter seriously limits its further application and development. For solving the above problems, in this paper, the reasons for the high failure rate of unmanned helicopter is analyzed and the corresponding solution schemes are proposed. The main problem of the failure cause of the unmanned helicopter is the aircraft engine fault, and the failure cause of the unmanned helicopter is analyzed particularly. In order to improving the safety performance of unmanned helicopter system, the scheme of adding the safety parachute system to the unmanned helicopter system is proposed and introduced. These schemes provide the safety redundancy of the unmanned helicopter system and lay on basis for the unmanned helicopter applying into residential areas.

  4. [Study on optimal model of hypothetical work injury insurance scheme].

    Science.gov (United States)

    Ye, Chi-yu; Dong, Heng-jin; Wu, Yuan; Duan, Sheng-nan; Liu, Xiao-fang; You, Hua; Hu, Hui-mei; Wang, Lin-hao; Zhang, Xing; Wang, Jing

    2013-12-01

    To explore an optimal model of hypothetical work injury insurance scheme, which is in line with the wishes of workers, based on the problems in the implementation of work injury insurance in China and to provide useful information for relevant policy makers. Multistage cluster sampling was used to select subjects: first, 9 small, medium, and large enterprises were selected from three cities (counties) in Zhejiang Province, China according to the economic development, transportation, and cooperation; then, 31 workshops were randomly selected from the 9 enterprises. Face-to-face interviews were conducted by trained interviewers using a pre-designed questionnaire among all workers in the 31 workshops. After optimization of hypothetical work injury insurance scheme, the willingness to participate in the scheme increased from 73.87%to 80.96%; the average willingness to pay for the scheme increased from 2.21% (51.77 yuan) to 2.38% of monthly wage (54.93 Yuan); the median willingness to pay for the scheme increased from 1% to 1.2% of monthly wage, but decreased from 35 yuan to 30 yuan. The optimal model of hypothetical work injury insurance scheme covers all national and provincial statutory occupational diseases and work accidents, as well as consultations about occupational diseases. The scheme is supposed to be implemented worldwide by the National Social Security Department, without regional differences. The premium is borne by the state, enterprises, and individuals, and an independent insurance fund is kept in the lifetime personal account for each of insured individuals. The premium is not refunded in any event. Compensation for occupational diseases or work accidents is unrelated to the enterprises of the insured workers but related to the length of insurance. The insurance becomes effective one year after enrollment, while it is put into effect immediately after the occupational disease or accident occurs. The optimal model of hypothetical work injury insurance

  5. a comparative study of prioritized handoff schemes with guard

    African Journals Online (AJOL)

    eobe

    duction in cell sizes, handoffs occur more frequently, and thereby result in increased volume of handoff related signaling. Therefore, a handoff scheme that can handle the increased signaling load while sustaining the standard QoS parameters is required.This work presents a comparative analysis of f. This work presents a ...

  6. Advanced Entry Adult Apprenticeship Training Scheme: A Case Study

    Science.gov (United States)

    Sparks, Alan; Ingram, Hadyn; Phillips, Sunny

    2009-01-01

    Purpose: The purpose of this paper is to evaluate an innovative way to train adult apprentices for the construction industry. Design/methodology/approach: The paper emphasizes that, in order to address skills shortages for international construction, training methods must be improved. It looks at the example of an adult apprenticeship scheme in…

  7. A Novel Rate Control Scheme for Constant Bit Rate Video Streaming

    Directory of Open Access Journals (Sweden)

    Venkata Phani Kumar M

    2015-08-01

    Full Text Available In this paper, a novel rate control mechanism is proposed for constant bit rate video streaming. The initial quantization parameter used for encoding a video sequence is determined using the average spatio-temporal complexity of the sequence, its resolution and the target bit rate. Simple linear estimation models are then used to predict the number of bits that would be necessary to encode a frame for a given complexity and quantization parameter. The experimental results demonstrate that our proposed rate control mechanism significantly outperforms the existing rate control scheme in the Joint Model (JM reference software in terms of Peak Signal to Noise Ratio (PSNR and consistent perceptual visual quality while achieving the target bit rate. Furthermore, the proposed scheme is validated through implementation on a miniature test-bed.

  8. Baseline scheme for polarization preservation and control in the MEIC ion complex

    Energy Technology Data Exchange (ETDEWEB)

    Derbenev, Yaroslav S. [Jefferson Lab, Newport News, VA (United States); Lin, Fanglei [Jefferson Lab, Newport News, VA (United States); Morozov, Vasiliy [Jefferson Lab, Newport News, VA (United States); Zhang, Yuhong [Jefferson Lab, Newport News, VA (United States); Kondratenko, Anatoliy [Science and Technique Laboratory Zaryad, Novosibirsk (Russian Federation); Kondratenko, M. A. [Science and Technique Laboratory Zaryad, Novosibirsk (Russian Federation); Filatov, Yury [MIPT, Dolgoprudny, Moscow (Russian Federation)

    2015-09-01

    The scheme for preservation and control of the ion polarization in the Medium-energy Electron-Ion Collider (MEIC) has been under active development in recent years. The figure-8 configuration of the ion rings provides a unique capability to control the polarization of any ion species including deuterons by means of "weak" solenoids rotating the particle spins by small angles. Insertion of "weak" solenoids into the magnetic lattices of the booster and collider rings solves the problem of polarization preservation during acceleration of the ion beam. Universal 3D spin rotators designed on the basis of "weak" solenoids allow one to obtain any polarization orientation at an interaction point of MEIC. This paper presents the baseline scheme for polarization preservation and control in the MEIC ion complex.

  9. A distributed model predictive control based load frequency control scheme for multi-area interconnected power system using discrete-time Laguerre functions.

    Science.gov (United States)

    Zheng, Yang; Zhou, Jianzhong; Xu, Yanhe; Zhang, Yuncheng; Qian, Zhongdong

    2017-05-01

    This paper proposes a distributed model predictive control based load frequency control (MPC-LFC) scheme to improve control performances in the frequency regulation of power system. In order to reduce the computational burden in the rolling optimization with a sufficiently large prediction horizon, the orthonormal Laguerre functions are utilized to approximate the predicted control trajectory. The closed-loop stability of the proposed MPC scheme is achieved by adding a terminal equality constraint to the online quadratic optimization and taking the cost function as the Lyapunov function. Furthermore, the treatments of some typical constraints in load frequency control have been studied based on the specific Laguerre-based formulations. Simulations have been conducted in two different interconnected power systems to validate the effectiveness of the proposed distributed MPC-LFC as well as its superiority over the comparative methods. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  10. Development of an Optimal Power Control Scheme for Wave-Offshore Hybrid Generation Systems

    Directory of Open Access Journals (Sweden)

    Seungmin Jung

    2015-08-01

    Full Text Available Integration technology of various distribution systems for improving renewable energy utilization has been receiving attention in the power system industry. The wave-offshore hybrid generation system (HGS, which has a capacity of over 10 MW, was recently developed by adopting several voltage source converters (VSC, while a control method for adopted power conversion systems has not yet been configured in spite of the unique system characteristics of the designated structure. This paper deals with a reactive power assignment method for the developed hybrid system to improve the power transfer efficiency of the entire system. Through the development and application processes for an optimization algorithm utilizing the real-time active power profiles of each generator, a feasibility confirmation of power transmission loss reduction was implemented. To find the practical effect of the proposed control scheme, the real system information regarding the demonstration process was applied from case studies. Also, an evaluation for the loss of the improvement rate was calculated.

  11. Self-Tuning Control Scheme Based on the Robustness σ-Modification Approach

    Directory of Open Access Journals (Sweden)

    Nabiha Touijer

    2017-01-01

    Full Text Available This paper deals with the self-tuning control problem of linear systems described by autoregressive exogenous (ARX mathematical models in the presence of unmodelled dynamics. An explicit scheme of control is described, which we use a recursive algorithm on the basis of the robustness σ-modification approach to estimate the parameters of the system, to solve the problem of regulation tracking of the system. This approach was designed with the assumptions that the norm of the vector of the parameters is well-known. A new quadratic criterion is proposed to develop a modified recursive least squares (M-RLS algorithm with σ-modification. The stability condition of the proposed estimation scheme is proved using the concepts of the small gain theorem. The effectiveness and reliability of the proposed M-RLS algorithm are shown by an illustrative simulation example. The effectiveness of the described explicit self-tuning control scheme is demonstrated by simulation results of the cruise control system for a vehicle.

  12. A comparative study of SAR data compression schemes

    Science.gov (United States)

    Lambert-Nebout, C.; Besson, O.; Massonnet, D.; Rogron, B.

    1994-01-01

    The amount of data collected from spaceborne remote sensing has substantially increased in the last years. During same time period, the ability to store or transmit data has not increased as quickly. At this time, there is a growing interest in developing compression schemes that could provide both higher compression ratios and lower encoding/decoding errors. In the case of the spaceborne Synthetic Aperture Radar (SAR) earth observation system developed by the French Space Agency (CNES), the volume of data to be processed will exceed both the on-board storage capacities and the telecommunication link. The objective of this paper is twofold: to present various compression schemes adapted to SAR data; and to define a set of evaluation criteria and compare the algorithms on SAR data. In this paper, we review two classical methods of SAR data compression and propose novel approaches based on Fourier Transforms and spectrum coding.

  13. A 24-Week, Randomized, Controlled Study to Evaluate the Tolerability, Safety and Efficacy of 2 Different Titration Schemes of the Rivastigmine Patch in Japanese Patients with Mild to Moderate Alzheimer's Disease.

    Science.gov (United States)

    Nakamura, Yu; Strohmaier, Christine; Tamura, Kaoru; Kataoka, Naoko; Nakano, Masayuki; Oda, Shoichiro; Nishimura, Kazuma; Homma, Akira

    2015-01-01

    To investigate whether 1-step titration of the rivastigmine patch (initiated at 5 cm(2) and titrated to 10 cm(2) after 4 weeks) is well tolerated in Japanese patients with Alzheimer's disease (AD) as compared to 3-step titration (initiated at 2.5 cm(2) and titrated by 2.5 cm(2) every 4 weeks to 10 cm(2)). A 24-week, multicenter, randomized, double-blind study was conducted in Japan between July 2012 and May 2014. Patients with mild to moderate AD aged 50-85 years were randomized 1:1 to 1-step or 3-step titration of the rivastigmine once-daily patch. The primary endpoint was the proportion of patients with adverse events leading to discontinuation. Of 216 patients randomized, 215 (1-step, n = 107; 3-step, n = 108) were included in the safety analysis. The primary endpoint outcome was 15.0% in the 1-step group and 18.5% in the 3-step group. The observed treatment difference was -3.6% (95% confidence interval: -17.0, 9.6), falling within the prespecified acceptance range. The tolerability of two different titration schemes was similar in Japanese patients with AD.

  14. A 24-Week, Randomized, Controlled Study to Evaluate the Tolerability, Safety and Efficacy of 2 Different Titration Schemes of the Rivastigmine Patch in Japanese Patients with Mild to Moderate Alzheimer's Disease

    Directory of Open Access Journals (Sweden)

    Yu Nakamura

    2015-09-01

    Full Text Available Aim: To investigate whether 1-step titration of the rivastigmine patch (initiated at 5 cm2 and titrated to 10 cm2 after 4 weeks is well tolerated in Japanese patients with Alzheimer's disease (AD as compared to 3-step titration (initiated at 2.5 cm2 and titrated by 2.5 cm2 every 4 weeks to 10 cm2. Methods: A 24-week, multicenter, randomized, double-blind study was conducted in Japan between July 2012 and May 2014. Patients with mild to moderate AD aged 50-85 years were randomized 1:1 to 1-step or 3-step titration of the rivastigmine once-daily patch. The primary endpoint was the proportion of patients with adverse events leading to discontinuation. Results: Of 216 patients randomized, 215 (1-step, n = 107; 3-step, n = 108 were included in the safety analysis. The primary endpoint outcome was 15.0% in the 1-step group and 18.5% in the 3-step group. The observed treatment difference was −3.6% (95% confidence interval: −17.0, 9.6, falling within the prespecified acceptance range. Conclusion: The tolerability of two different titration schemes was similar in Japanese patients with AD.

  15. A Secure and Verifiable Outsourced Access Control Scheme in Fog-Cloud Computing.

    Science.gov (United States)

    Fan, Kai; Wang, Junxiong; Wang, Xin; Li, Hui; Yang, Yintang

    2017-07-24

    With the rapid development of big data and Internet of things (IOT), the number of networking devices and data volume are increasing dramatically. Fog computing, which extends cloud computing to the edge of the network can effectively solve the bottleneck problems of data transmission and data storage. However, security and privacy challenges are also arising in the fog-cloud computing environment. Ciphertext-policy attribute-based encryption (CP-ABE) can be adopted to realize data access control in fog-cloud computing systems. In this paper, we propose a verifiable outsourced multi-authority access control scheme, named VO-MAACS. In our construction, most encryption and decryption computations are outsourced to fog devices and the computation results can be verified by using our verification method. Meanwhile, to address the revocation issue, we design an efficient user and attribute revocation method for it. Finally, analysis and simulation results show that our scheme is both secure and highly efficient.

  16. A Fairness-Based Access Control Scheme to Optimize IPTV Fast Channel Changing

    Directory of Open Access Journals (Sweden)

    Junyu Lai

    2014-01-01

    Full Text Available IPTV services are typically featured with a longer channel changing delay compared to the conventional TV systems. The major contributor to this lies in the time spent on intraframe (I-frame acquisition during channel changing. Currently, most widely adopted fast channel changing (FCC methods rely on promptly transmitting to the client (conducting the channel changing a retained I-frame of the targeted channel as a separate unicasting stream. However, this I-frame acceleration mechanism has an inherent scalability problem due to the explosions of channel changing requests during commercial breaks. In this paper, we propose a fairness-based admission control (FAC scheme for the original I-frame acceleration mechanism to enhance its scalability by decreasing the bandwidth demands. Based on the channel changing history of every client, the FAC scheme can intelligently decide whether or not to conduct the I-frame acceleration for each channel change request. Comprehensive simulation experiments demonstrate the potential of our proposed FAC scheme to effectively optimize the scalability of the I-frame acceleration mechanism, particularly in commercial breaks. Meanwhile, the FAC scheme only slightly increases the average channel changing delay by temporarily disabling FCC (i.e., I-frame acceleration for the clients who are addicted to frequent channel zapping.

  17. Dynamic Evaluation of LCL-type Grid-Connected Inverters with Different Current Feedback Control Schemes

    DEFF Research Database (Denmark)

    Han, Yang; Li, Zipeng; Guerrero, Josep M.

    2015-01-01

    typical current feedback control schemes in LCL grid-connected system are analyzed and compared systematically. Analysis in s-domain take the effect of the digital computation and modulation delay into account. The stability analysis is presented by root locus in the discrete domain, the optimal values...... of the controller and filter with different feedback configurations are provided. The impacts of digital delay, PR parameters and LCL parameters on different control strategies are also investigated. Finally, the theoretical analysis are validated by simulation results....

  18. Improved FRT Control Scheme for DFIG Wind Turbine Connected to a Weak Grid

    DEFF Research Database (Denmark)

    Abulanwar, Elsayed; Chen, Zhe; Iov, Florin

    2013-01-01

    This paper presents an improved coordinated fault ridethrough (FRT) control strategy for a doubly fed induction generator (DFIG) based wind turbine, (WT), in a weak grid. A technique for grid synchronization against voltage excursions, i.e., a Dual Second Order Generalized Integrator – Frequency......), controller to counteract current ripples and tackle the DC link voltage fluctuations. Also, a reactive power support scheme to manage the DFIG reactive power during contingencies and fulfill the grid codes obligations is presented. Moreover, additional control terms are employed with the DFIG converters...

  19. A Virtual Synchronous Generator Based Hierarchical Control Scheme of Distributed Generation Systems

    Directory of Open Access Journals (Sweden)

    Gang Yao

    2017-12-01

    Full Text Available Sustainable energy-based generation systems, such as photovoltaic and wind turbine generation systems, normally adopt inverters to connect to the grid. These power electronic interfaces possess the characteristics of small inertia and small output impedance, which create difficulties to stabilize the voltage and frequency of a distributed power source. To deal with this problem, a Virtual Synchronous Generator (VSG-based inverter control method is presented in this paper by introducing virtual inertia and damping coefficient into the control loop to emulate the dynamic behavior of a traditional synchronous generator. Based on this VSG control method, a three-layer hierarchical control scheme is further proposed to increase the control accuracy of the voltage and frequency in a VSG-based distributed generation system with parallel inverters. The principle of the VSG control method, the system stability analysis, the design process of the hierarchical control structure, and the frequency/voltage secondary regulation processes are all specified in this paper. Finally, some numerical simulations are carried out and the effectiveness of proposed control scheme is verified by the simulation results analysis.

  20. Effect of different lateral occlusion schemes on peri-implant strain: A laboratory study

    OpenAIRE

    Lo, Jennifer; ABDUO, Jaafar; Palamara, Joseph

    2017-01-01

    PURPOSE This study aims to investigate the effects of four different lateral occlusion schemes and different excursions on peri-implant strains of a maxillary canine implant. MATERIALS AND METHODS Four metal crowns with different occlusion schemes were attached to an implant in the maxillary canine region of a resin model. The included schemes were canine-guided (CG) occlusion, group function (GF) occlusion, long centric (LC) occlusion, and implant-protected (IP) occlusion. Each crown was loa...

  1. Segmentation Scheme for Safety Enhancement of Engineered Safety Features Component Control System

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sangseok; Sohn, Kwangyoung [Korea Reliability Technology and System, Daejeon (Korea, Republic of); Lee, Junku; Park, Geunok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    Common Caused Failure (CCF) or undetectable failure would adversely impact safety functions of ESF-CCS in the existing nuclear power plants. We propose the segmentation scheme to solve these problems. Main function assignment to segments in the proposed segmentation scheme is based on functional dependency and critical function success path by using the dependency depth matrix. The segment has functional independence and physical isolation. The segmentation structure is that prohibit failure propagation to others from undetectable failures. Therefore, the segmentation system structure has robustness to undetectable failures. The segmentation system structure has functional diversity. The specific function in the segment defected by CCF, the specific function could be maintained by diverse control function that assigned to other segments. Device level control signals and system level control signals are separated and also control signal and status signals are separated due to signal transmission paths are allocated independently based on signal type. In this kind of design, single device failure or failures on signal path in the channel couldn't result in the loss of all segmented functions simultaneously. Thus the proposed segmentation function is the design scheme that improves availability of safety functions. In conventional ESF-CCS, the single controller generates the signal to control the multiple safety functions, and the reliability is achieved by multiplication within the channel. This design has a drawback causing the loss of multiple functions due to the CCF (Common Cause Failure) and single failure Heterogeneous controller guarantees the diversity ensuring the execution of safety functions against the CCF and single failure, but requiring a lot of resources like manpower and cost. The segmentation technology based on the compartmentalization and functional diversification decreases the CCF and single failure nonetheless the identical types of

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

    DEFF Research Database (Denmark)

    Han, Yang; Shen, Pan; Zhao, Xin

    2017-01-01

    In this paper, the modeling, controller design, and stability analysis of the islanded microgrid (MG) using enhanced hierarchical control structure with multiple current loop damping schemes is proposed. The islanded MG is consisted of the parallel-connected voltage source inverters using LCL...... of the state matrix. The moving average filter-based sequence decomposition method is proposed to extract the fundamental positive and negative sequences, and harmonic components. The multiple inner current loop damping scheme is presented, including the virtual positive, virtual negative and variable harmonic...... frequency, and virtual variable harmonic impedance loop at harmonic frequencies, and the inner voltage and current loop controllers. A small-signal model for the primary and secondary controls with additional phase-shift loop is presented, which shows an over-damped feature from eigenvalue analysis...

  3. A self-learning call admission control scheme for CDMA cellular networks.

    Science.gov (United States)

    Liu, Derong; Zhang, Yi; Zhang, Huaguang

    2005-09-01

    In the present paper, a call admission control scheme that can learn from the network environment and user behavior is developed for code division multiple access (CDMA) cellular networks that handle both voice and data services. The idea is built upon a novel learning control architecture with only a single module instead of two or three modules in adaptive critic designs (ACDs). The use of adaptive critic approach for call admission control in wireless cellular networks is new. The call admission controller can perform learning in real-time as well as in offline environments and the controller improves its performance as it gains more experience. Another important contribution in the present work is the choice of utility function for the present self-learning control approach which makes the present learning process much more efficient than existing learning control methods. The performance of our algorithm will be shown through computer simulation and compared with existing algorithms.

  4. A Fuzzy Predictive PID Control Scheme for the Excitation System of Synchronous Generator

    Directory of Open Access Journals (Sweden)

    Zheng Yang

    2016-01-01

    Full Text Available With the rapid development of the process control theories in the electrical engineering, new control strategies which lead to better performances are urgently demanded for the excitation control of synchronous generators. For the sake of improving the convergence rate of the terminal voltage and covering the weakness in the adaptability of operational conditions of conventional controls in disturbances, a fuzzy predictive PID excitation control method is proposed in this paper. This control scheme can be divided into three steps in every sample interval: PID parameter adaptation, rolling state prediction and real-time control movement integration. Numerical simulations have been conducted under different operational conditions with the proposed method as well as the conventional ones, respectively. Experimental comparisons indicate the superiority in voltage regulation performance of the proposed method.

  5. Homography-based control scheme for mobile robots with nonholonomic and field-of-view constraints.

    Science.gov (United States)

    López-Nicolás, Gonzalo; Gans, Nicholas R; Bhattacharya, Sourabh; Sagüés, Carlos; Guerrero, Josechu J; Hutchinson, Seth

    2010-08-01

    In this paper, we present a visual servo controller that effects optimal paths for a nonholonomic differential drive robot with field-of-view constraints imposed by the vision system. The control scheme relies on the computation of homographies between current and goal images, but unlike previous homography-based methods, it does not use the homography to compute estimates of pose parameters. Instead, the control laws are directly expressed in terms of individual entries in the homography matrix. In particular, we develop individual control laws for the three path classes that define the language of optimal paths: rotations, straight-line segments, and logarithmic spirals. These control laws, as well as the switching conditions that define how to sequence path segments, are defined in terms of the entries of homography matrices. The selection of the corresponding control law requires the homography decomposition before starting the navigation. We provide a controllability and stability analysis for our system and give experimental results.

  6. Institutional analysis of incentive schemes for ecosystem service provision - a comparative study across four European countries

    DEFF Research Database (Denmark)

    Prokofieva, Irina; Górriz, Elena; Boon, Tove Enggrob

    2014-01-01

    Incentive schemes and payments for ecosystem services attract increasing attention as a means for aligning the interests of landowners and society by remunerating forest owners for the goods and services their forests produce. As incentive schemes expand around the world, questions related...... and Italy. The analysed schemes are predominantly aimed at enhancing biodiversity and improving recreation. One of the schemes is also related to preserving a variety of forest ecosystem services from forest fires. The incentive schemes are studied following a framework for the institutional analysis of PES...... developed by Prokofieva and Gorriz (Prokofieva, I. and Gorriz, E. 2013: Institutional analysis of incentives for the provision of forest goods and services: an assessment of incentive schemes in Catalonia (North-East Spain), Forest Policy and Economics, 37, 104-114.). We focus on actor and institutional...

  7. Observerless Scheme for Sensorless Speed Control of PMSM Using Direct Torque Control Method With LP Filter

    OpenAIRE

    BEKIROGLU, N.; OZCIRA, S.

    2010-01-01

    In this study, direct torque control (DTC) of a permanent magnet synchronous motor is realized with a sensorless speed control technique without using an observer. Space vector pulse width modulation (SVPWM) technique is applied in order to determine the switching sequence of the voltage source inverter. Torque and flux, the main variables of the DTC, are estimated by using the mathematical model of the motor. Estimated torque and flux values are compared with their references in every con...

  8. Experiences of an exercise referral scheme from the perspective of people with chronic stroke: a qualitative study.

    Science.gov (United States)

    Sharma, Helen; Bulley, Cathy; van Wijck, Frederike M J

    2012-12-01

    To explore stroke survivors' experiences of undertaking exercise in the context of an exercise referral scheme for people with chronic stroke. A qualitative design, using semi-structured interviews within a constructivist framework to explore the experiences of individual participants. Verbatim transcripts were thematically analysed. Rigour mechanisms included respondent validation, peer checking, and reflexivity. An exercise referral scheme, based at a leisure centre in South London. Nine community-dwelling stroke survivors took part; 5 male and 4 female, mean age 51 years (range 37-61 years); time post stroke 1-4 years, with mixed ethnic backgrounds. Participants described greater physical and psychological well-being following participation in the exercise referral scheme. Categories that emerged were: improved exercise engagement and confidence, more internalised perceptions of control and enhanced lifestyle, work and social roles. Categories linked to form a master theme, labelled: 'Exercise Referral Scheme as a catalyst for regaining independence.' This study supports the value of exercise referral schemes in enabling people with stroke to engage in exercise. For participants in this study, the scheme seemed influential in the process of regaining independence. Copyright © 2011 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

  9. Multi-Agent System Based Special Protection and Emergency Control Scheme against Cascading Events in Power System

    DEFF Research Database (Denmark)

    Liu, Zhou

    the proposed protection strategy in this thesis, a real time simulation platform based on Real Time Digital Simulator (RTDS) and LabVIEW is built. In this platform, the cases of cascaded blackouts are simulated on the test system simplified from the East Denmark power system. For the MAS based control system......, the distributed power system agents are set up in RTDS, while the agents in higher level are designed by LabVIEW toolkits. The case studies and simulation results demonstrate the effectiveness of real time application of the proposed MAS based special protection and emergency control scheme against the cascaded...

  10. An Overview of Demand Side Management Control Schemes for Buildings in Smart Grids

    DEFF Research Database (Denmark)

    Kosek, Anna Magdalena; Costanzo, Giuseppe Tommaso; Bindner, Henrik W.

    2013-01-01

    demand is needed. The research area of demand side management is still very much in flux and several options are being presented which can all be used to manage loads in order to achieve a flexible and more responsive demand. These different control schemes are developed with different organization...... of the power sector in mind and thus can differ significantly in their architecture, their integration into the various markets, their integration into distribution network operation and several other aspects. This paper proposes a classification of load control policies for demand side management in smart...

  11. Analysis of various control schemes for minimal Total Harmonic Distortion in cascaded H-bridge multilevel inverter

    Directory of Open Access Journals (Sweden)

    Janardhan Kavali

    2016-12-01

    Full Text Available Multilevel inverters are becoming more popular in the power conversion systems for high power and power quality demanding applications. The MATLAB based simulation on SIMULINK platform is presented for the Single Phase five level cascaded H-bridge Multilevel Inverter (CHB-MLI topology with less number of switches and with different control schemes and Sinusoidal Pulse Width Modulation (SPWM schemes. A detailed comparison of various control schemes is presented in this paper with reference to Total Harmonic Distortion (THD in the output voltage and utilization factor of the power devices. It is observed that among all the control schemes, the THD is minimum in the Sinusoidal Pulse Width Modulation-Phase Disposition (SPWM-PD scheme with variable carrier wave magnitude.

  12. A Case Study: Reading Strategies Training Scheme in a Hong Kong Primary School

    Science.gov (United States)

    Lee, Ho Cheung

    2017-01-01

    This article describes a case study on a reading programme, named Reading Strategies Training Scheme (RSTS), for second language learning in a Hong Kong primary (elementary) school. The scheme, serving learners of English as a second language from Primary One to Six (ages 6--12), was developed by the school's English teaching team. As it was being…

  13. A DC-Link Modulation Scheme with Phase-Shifted Current Control for Harmonic Cancellations in Multidrive Applications

    DEFF Research Database (Denmark)

    Yang, Yongheng; Davari, Pooya; Zare, Firuz

    2016-01-01

    of a new DC link modulation scheme with a phase-shifted current control enabled by the SCR. The DC-link current modulation scheme is implemented by adding and subtracting specific modulation levels, which makes the total currents drawn from the grid “multi-level”, resulting in an improved current quality...

  14. PSO-tuned PID controller for coupled tank system via priority-based fitness scheme

    Science.gov (United States)

    Jaafar, Hazriq Izzuan; Hussien, Sharifah Yuslinda Syed; Selamat, Nur Asmiza; Abidin, Amar Faiz Zainal; Aras, Mohd Shahrieel Mohd; Nasir, Mohamad Na'im Mohd; Bohari, Zul Hasrizal

    2015-05-01

    The industrial applications of Coupled Tank System (CTS) are widely used especially in chemical process industries. The overall process is require liquids to be pumped, stored in the tank and pumped again to another tank. Nevertheless, the level of liquid in tank need to be controlled and flow between two tanks must be regulated. This paper presents development of an optimal PID controller for controlling the desired liquid level of the CTS. Two method of Particle Swarm Optimization (PSO) algorithm will be tested in optimizing the PID controller parameters. These two methods of PSO are standard Particle Swarm Optimization (PSO) and Priority-based Fitness Scheme in Particle Swarm Optimization (PFPSO). Simulation is conducted within Matlab environment to verify the performance of the system in terms of settling time (Ts), steady state error (SSE) and overshoot (OS). It has been demonstrated that implementation of PSO via Priority-based Fitness Scheme (PFPSO) for this system is potential technique to control the desired liquid level and improve the system performances compared with standard PSO.

  15. Influences of Different Land Use Spatial Control Schemes on Farmland Conversion and Urban Development

    Science.gov (United States)

    Zhou, Min; Tan, Shukui; Zhang, Lu

    2015-01-01

    Land use planning is always officially implemented as an effective tool to control urban development and protect farmland. However, its impact on land use change remains untested in China. Using a case study of Hang-Jia-Hu region, the main objective of this paper was to investigate the influence of different land use spatial control schemes on farmland conversion and urban development. Comparisons of farmland conversion and urban development patterns between the urban planning area and the non-urban planning area were characterized by using remote sensing, geographical information systems, and landscape metrics. Results indicated that farmland conversion in the non-urban planning area was more intensive than that in the urban planning area, and that farmland patterns was more fragmented in the non-urban planning area. Built-up land patterns in the non-urban planning area showed a trend of aggregation, while those in the urban planning area had a dual trend of fragmentation and aggregation. Existing built-up areas had less influence on built-up land sprawl in the non-urban planning area than that in the urban planning area. Built-up land sprawl in the form of continuous development in the urban planning area led to farmland conversion; and in the non-urban planning area, built-up land sprawl in the form of leapfrogging development resulted in farmland areal declines and fragmentation. We argued that it is a basic requirement to integrate land use plans in urban and non-urban planning areas for land use planning and management. PMID:25915897

  16. A Fault-tolerable Control Scheme for an Open-frame Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    Huang Hai

    2014-05-01

    Full Text Available Open-frame is one of the major types of structures of Remote Operated Vehicles (ROV because it is easy to place sensors and operations equipment onboard. Firstly, this paper designed a petri-based recurrent neural network (PRFNN to improve the robustness with response to nonlinear characteristics and strong disturbance of an open-frame underwater vehicle. A threshold has been set in the third layer to reduce the amount of calculations and regulate the training process. The whole network convergence is guaranteed with the selection of learning rate parameters. Secondly, a fault tolerance control (FTC scheme is established with the optimal allocation of thrust. Infinity-norm optimization has been combined with 2-norm optimization to construct a bi-criteria primal-dual neural network FTC scheme. In the experiments and simulation, PRFNN outperformed fuzzy neural networks in motion control, while bi-criteria optimization outperformed 2-norm optimization in FTC, which demonstrates that the FTC controller can improve computational efficiency, reduce control errors, and implement fault tolerable thrust allocation.

  17. Model-Based Predictive Control Scheme for Cost Optimization and Balancing Services for Supermarket Refrigeration Systems

    DEFF Research Database (Denmark)

    Weerts, Hermanus H. M.; Shafiei, Seyed Ehsan; Stoustrup, Jakob

    2014-01-01

    A new formulation of model predictive control for supermarket refrigeration systems is proposed to facilitate the regulatory power services as well as energy cost optimization of such systems in the smart grid. Nonlinear dynamics existed in large-scale refrigeration plants challenges the predictive...... control design. It is however shown that taking into account the knowledge of different time scales in the dynamical subsystems makes possible a linear formulation of a centralized predictive controller. A realistic scenario of regulatory power services in the smart grid is considered and formulated...... in the same objective as of cost optimization one. A simulation benchmark validated against real data and including significant dynamics of the system are employed to show the effectiveness of the proposed control scheme....

  18. A Polar Fuzzy Control Scheme for Hybrid Power System Using Vehicle-To-Grid Technique

    Directory of Open Access Journals (Sweden)

    Mohammed Elsayed Lotfy

    2017-07-01

    Full Text Available A novel polar fuzzy (PF control approach for a hybrid power system is proposed in this research. The proposed control scheme remedies the issues of system frequency and the continuity of demand supply caused by renewable sources’ uncertainties. The hybrid power system consists of a wind turbine generator (WTG, solar photovoltaics (PV, a solar thermal power generator (STPG, a diesel engine generator (DEG, an aqua-electrolyzer (AE, an ultra-capacitor (UC, a fuel-cell (FC, and a flywheel (FW. Furthermore, due to the high cost of the battery energy storage system (BESS, a new idea of vehicle-to-grid (V2G control is applied to use the battery of the electric vehicle (EV as equivalent to large-scale energy storage units instead of small batteries to improve the frequency stability of the system. In addition, EV customers’ convenience is taken into account. A minimal-order observer is used to estimate the supply error. Then, the area control error (ACE signal is calculated in terms of the estimated supply error and the frequency deviation. ACE is considered in the frequency domain. Two PF approaches are utilized in the intended system. The mission of each controller is to mitigate one frequency component of ACE. The responsibility for ACE compensation is shared among all parts of the system according to their speed of response. The performance of the proposed control scheme is compared to the conventional fuzzy logic control (FLC. The effectiveness and robustness of the proposed control technique are verified by numerical simulations under various scenarios.

  19. Robust fuzzy neural network sliding mode control scheme for IPMSM drives

    Science.gov (United States)

    Leu, V. Q.; Mwasilu, F.; Choi, H. H.; Lee, J.; Jung, J. W.

    2014-07-01

    This article proposes a robust fuzzy neural network sliding mode control (FNNSMC) law for interior permanent magnet synchronous motor (IPMSM) drives. The proposed control strategy not only guarantees accurate and fast command speed tracking but also it ensures the robustness to system uncertainties and sudden speed and load changes. The proposed speed controller encompasses three control terms: a decoupling control term which compensates for nonlinear coupling factors using nominal parameters, a fuzzy neural network (FNN) control term which approximates the ideal control components and a sliding mode control (SMC) term which is proposed to compensate for the errors of that approximation. Next, an online FNN training methodology, which is developed using the Lyapunov stability theorem and the gradient descent method, is proposed to enhance the learning capability of the FNN. Moreover, the maximum torque per ampere (MTPA) control is incorporated to maximise the torque generation in the constant torque region and increase the efficiency of the IPMSM drives. To verify the effectiveness of the proposed robust FNNSMC, simulations and experiments are performed by using MATLAB/Simulink platform and a TI TMS320F28335 DSP on a prototype IPMSM drive setup, respectively. Finally, the simulated and experimental results indicate that the proposed design scheme can achieve much better control performances (e.g. more rapid transient response and smaller steady-state error) when compared to the conventional SMC method, especially in the case that there exist system uncertainties.

  20. Multiagent System-Based Wide-Area Protection and Control Scheme against Cascading Events

    DEFF Research Database (Denmark)

    Liu, Zhou; Chen, Zhe; Sun, Haishun

    2015-01-01

    In this paper, a multi agent system (MAS) based wide area protection and control scheme is proposed to deal with the long term voltage instability induced cascading trips. Based on sensitivity analysis between the relay operation margin and power system state variables, an optimal emergency contr...... strategy. A hybrid simulation platform based on LabVIEW and real time digital simulator (RTDS) is set up to simulate a blackout case in the power system of Eastern Denmark and to demonstrate the effectiveness of the proposed MAS based protection strategy....

  1. Development of a Blood Pressure Measurement Instrument with Active Cuff Pressure Control Schemes

    Directory of Open Access Journals (Sweden)

    Chung-Hsien Kuo

    2017-01-01

    Full Text Available This paper presents an oscillometric blood pressure (BP measurement approach based on the active control schemes of cuff pressure. Compared with conventional electronic BP instruments, the novelty of the proposed BP measurement approach is to utilize a variable volume chamber which actively and stably alters the cuff pressure during inflating or deflating cycles. The variable volume chamber is operated with a closed-loop pressure control scheme, and it is activated by controlling the piston position of a single-acting cylinder driven by a screw motor. Therefore, the variable volume chamber could significantly eliminate the air turbulence disturbance during the air injection stage when compared to an air pump mechanism. Furthermore, the proposed active BP measurement approach is capable of measuring BP characteristics, including systolic blood pressure (SBP and diastolic blood pressure (DBP, during the inflating cycle. Two modes of air injection measurement (AIM and accurate dual-way measurement (ADM were proposed. According to the healthy subject experiment results, AIM reduced 34.21% and ADM reduced 15.78% of the measurement time when compared to a commercial BP monitor. Furthermore, the ADM performed much consistently (i.e., less standard deviation in the measurements when compared to a commercial BP monitor.

  2. An adaptive control scheme for hyperbolic partial differential equation system (drilling system with unknown coefficient

    Directory of Open Access Journals (Sweden)

    Farahani Hamed Shirinabadi

    2017-03-01

    Full Text Available The adaptive boundary stabilization is investigated for a class of systems described by second-order hyperbolic PDEs with unknown coefficient. The proposed control scheme only utilizes measurement on top boundary and assume anti-damping dynamics on the opposite boundary which is the main feature of our work. To cope with the lack of full state measurements, we introduce Riemann variables which allow us reformulate the second-order in time hyperbolic PDE as a system with linear input-delay dynamics. Then, the infinite-dimensional time-delay tools are employed to design the controller. Simulation results which applied on mathematical model of drilling system are given to demonstrate the effectiveness of the proposed control approach.

  3. Visual Control for Unicycle-Like Mobile Robots Formation Under the Leader-Follower Scheme

    Directory of Open Access Journals (Sweden)

    Bugarin-Carlos Eusebio

    2014-10-01

    Full Text Available This paper describes a visual control proposal for the formation of unicycle-like mobile robots under the leader-follower scheme. It is considered a single fixed camera observing the robots workspace that, in terms of the processed information, can be shared by both the leader robot and the follower robot. This would enable the implementation of this proposal to be performed by centralized or decentralized control strategies. For the purpose of simplifying the analysis, it is also considered that the image plane is parallel to the robots motion plane. The formation objective is established directly in image space and the proposed visual controller does not depend explicitly on the vision system parameters (extrinsic or intrinsic; which together represents the main contribution of this paper. Finally, also as an important part of this work, to validate the proposed theory satisfactory experiments using a real-time and high-speed vision system are detailed.

  4. A Modified Control Scheme of Droop-Based Converters for Power Stability Analysis in Microgrids

    Directory of Open Access Journals (Sweden)

    Igor Usunariz

    2015-01-01

    Full Text Available Microgrid is principally an active distribution network since it aggregates numerous DG systems through their interface converters and different loads at distribution level. This paper discusses the power sharing in autonomous AC-microgrid infrastructure by common P-f and Q-V˙ droop control schemes on parallel-connected converters. Moreover, this research work proposes a frequency and voltage restoration mechanism through the utilization of secondary control. Experimental results are presented for a two-50 kVA parallel-connected converter-based system, demonstrating the necessity for the proper operation of the secondary control in order to monitor the system’s capability to withstand any perturbations that may occur and to ensure the system’s security.

  5. 'Just another incentive scheme': a qualitative interview study of a local pay-for-performance scheme for primary care.

    Science.gov (United States)

    Hackett, Julia; Glidewell, Liz; West, Robert; Carder, Paul; Doran, Tim; Foy, Robbie

    2014-10-25

    A range of policy initiatives have addressed inequalities in healthcare and health outcomes. Local pay-for-performance schemes for primary care have been advocated as means of enhancing clinical ownership of the quality agenda and better targeting local need compared with national schemes such as the UK Quality and Outcomes Framework (QOF). We investigated whether professionals' experience of a local scheme in one English National Health Service (NHS) former primary care trust (PCT) differed from that of the national QOF in relation to the goal of reducing inequalities. We conducted retrospective semi-structured interviews with primary care professionals implementing the scheme and those involved in its development. We purposively sampled practices with varying levels of population socio-economic deprivation and achievement. Interviews explored perceptions of the scheme and indicators, likely mechanisms of influence on practice, perceived benefits and harms, and how future schemes could be improved. We used a framework approach to analysis. Thirty-eight professionals from 16 general practices and six professionals involved in developing local indicators participated. Our findings cover four themes: ownership, credibility of the indicators, influences on behaviour, and exacerbated tensions. We found little evidence that the scheme engendered any distinctive sense of ownership or experiences different from the national scheme. Although the indicators and their evidence base were seldom actively questioned, doubts were expressed about their focus on health promotion given that eventual benefits relied upon patient action and availability of local resources. Whilst practices serving more affluent populations reported status and patient benefit as motivators for participating in the scheme, those serving more deprived populations highlighted financial reward. The scheme exacerbated tensions between patient and professional consultation agendas, general practitioners

  6. Coordinated single-phase control scheme for voltage unbalance reduction in low voltage network.

    Science.gov (United States)

    Pullaguram, Deepak; Mishra, Sukumar; Senroy, Nilanjan

    2017-08-13

    Low voltage (LV) distribution systems are typically unbalanced in nature due to unbalanced loading and unsymmetrical line configuration. This situation is further aggravated by single-phase power injections. A coordinated control scheme is proposed for single-phase sources, to reduce voltage unbalance. A consensus-based coordination is achieved using a multi-agent system, where each agent estimates the averaged global voltage and current magnitudes of individual phases in the LV network. These estimated values are used to modify the reference power of individual single-phase sources, to ensure system-wide balanced voltages and proper power sharing among sources connected to the same phase. Further, the high X / R ratio of the filter, used in the inverter of the single-phase source, enables control of reactive power, to minimize voltage unbalance locally. The proposed scheme is validated by simulating a LV distribution network with multiple single-phase sources subjected to various perturbations.This article is part of the themed issue 'Energy management: flexibility, risk and optimization'. © 2017 The Author(s).

  7. [Modeling and simulation activities to design sampling scheme for population pharmacokinetic study on amlodipine].

    Science.gov (United States)

    Zuo, Xiao-Cong; Yuan, Hong; Zhang, Bi-Kui; Ng, Chee M; Barrett, Jeff S; Yang, Guo-Ping; Huang, Zhi-Jun; Pei, Qi; Guo, Ren; Zhou, Ya-Nan; Jing, Ning-Ning; Di, Wu

    2012-07-01

    Reasonable sampling scheme is the important basis for establishing reliable population pharmacokinetic model. It is an effective method for estimation of population pharmacokinetic parameters with sparse data to perform population pharmacokinetic analysis using the nonlinear mixed-effects models. We designed the sampling scheme for amlodipine based on D-optimal sampling strategy and Bayesian estimation method. First, optimized sample scenarios were designed using WinPOPT software according to the aim, dosage regimen and visit schedule of the clinical study protocol, and the amlodipine population model reported by Rohatagi et al. Second, we created a NONMEM-formatted dataset (n = 400) for each sample scenario via Monte Carlo simulation. Third, the estimation of amlodipine pharmacokinetic parameters (clearance (CL/F), volume (V/F) and Ka) was based on the simulation results. All modeling and simulation exercises were conducted with NONMEM version 7.2. Finally, the accuracy and precision of the estimated parameters were evaluated using the mean prediction error (MPE) and the mean absolute error (MAPE), respectively. Among the 6 schemes, schemes 6 and 3 have good accuracy and precision. MPE is 0.1% for scheme 6 and -0.6% for scheme 3, respectively. MAPE is 0.7% for both schemes. There is no significant difference in MPE and MAPE of volume among them. Therefore, we select scheme 3 as the final sample scenario because it has good accuracy and precision and less sample points. This research aims to provide scientific and effective sampling scheme for population pharmacokinetic (PK) study of amlodipine in patients with renal impairment and hypertension, provide a scientific method for an optimum design in clinical population PK/PD (pharmacodynamics) research.

  8. A novel decentralized hierarchical access control scheme for the medical scenario

    DEFF Research Database (Denmark)

    Eskeland, Sigurd; Prasad, Neeli R.

    2006-01-01

    Electronic patient records contains highly personal and confidential information that it is essential to keep private. Thus, only the medical professionals providing care to a patient should access the patient record of the concerning patient. As personal medical data can be considered...... to be the property of the corresponding patient, it is justified that patients should have the opportunity to exert control over their own data. In this paper, we propose a cryptographic access control scheme allowing patients to grant medical teams authorizations to access their medical data. Moreover......, the hierarchical aspects of teams are taken into account so that the modules of the patient record are to be accessed according to the individual privileges of the medical professionals of the team. Thus, more privileged users obtain larger portions of the data than less privileged users....

  9. Description and first results of a BVDV control scheme in Brittany (western France).

    Science.gov (United States)

    Joly, Alain; Fourichon, Christine; Beaudeau, François

    2005-11-15

    A collective zoo-sanitary control scheme for BVDV has been implemented in Brittany in successive steps since 1998. Prior evaluation of prevalence and dynamics of infection through bulk-milk ELISA showed that 40% of the dairy herds were likely to be free of BVDV but that, in the long term, no improvement was to be expected without control of new infections. The next step was a test-and-cull programme for PI animals in ELISA positive herds. Ten percentage of the herds were found to have at least one PI animal. The incidence decreased during this step. To lower costs of testing traded animals, a database was developed to collect all the available information to trace animals already known to be non-PI.

  10. Optimal placement of FACTS controller scheme for enhancement of power system security in Indian scenario

    Directory of Open Access Journals (Sweden)

    Imran Khan

    2015-09-01

    Full Text Available This paper presents a FACTS operation scheme to enhance the power system security. Three main generic types of FACTS devices are introduced. Line overloads are solved by controlling active power of series compensators and low voltages are solved by controlling reactive power of shunt compensators, respectively. Especially, the combined series-shunt compensators such as UPFC are applied to solve both line congestions and low voltages simultaneously. Two kinds of indices that indicate the security level related to line flow and bus voltage is utilized in this paper. They are iteratively minimized to determine operating points of the devices for security enhancement. The sensitivity vectors of the indices are derived to determine the direction of minimum. The proposed algorithm is verified on the IEEE 14-bus system with FACTS devices in a normal condition and in a line-faulted contingency.

  11. A novel decentralized hierarchical access control scheme for the medical scenario

    DEFF Research Database (Denmark)

    Eskeland, Sigurd; Prasad, Neeli R.

    2006-01-01

    Electronic patient records contains highly personal and confidential information that it is essential to keep private. Thus, only the medical professionals providing care to a patient should access the patient record of the concerning patient. As personal medical data can be considered......, the hierarchical aspects of teams are taken into account so that the modules of the patient record are to be accessed according to the individual privileges of the medical professionals of the team. Thus, more privileged users obtain larger portions of the data than less privileged users....... to be the property of the corresponding patient, it is justified that patients should have the opportunity to exert control over their own data. In this paper, we propose a cryptographic access control scheme allowing patients to grant medical teams authorizations to access their medical data. Moreover...

  12. Structure of a scheme of emergency control to avoid blackout due to interconnection lines loss

    Energy Technology Data Exchange (ETDEWEB)

    Luz, L.T. da; Werberich, L.C.; Herve, H.M. [Companhia Estadual de Energia Eletrica do Estado do Rio Grande do Sul (CEEE), Porto Alegre, RS (Brazil)

    1994-12-31

    This work presents the structure of Gravatai Emergency Control Scheme (ECS) with short about its development and operation. This ECS was made to avoid two kinds of problems for the systems of Companhia Estadual de Energia Eletrica (CEEE). The first one is the voltage collapse that happens after the opening of one of the 525 kv LTs of the interconnection with the Brazilian Interconnected System (BIS). The second one is the CEEE isolating after the 525 kV network loss. We show the ECS existence reason and we describe its functional structure, the substations, the circuits and the amount of load shedding involved by the system. Finally, we present the project of a control structure based on microcomputer which is being developed for this ECS. (author) 3 refs., 11 figs.

  13. Randomised controlled trial of effectiveness of Leicester hospital at home scheme compared with hospital care.

    Science.gov (United States)

    Wilson, A; Parker, H; Wynn, A; Jagger, C; Spiers, N; Jones, J; Parker, G

    1999-12-11

    To compare effectiveness of patient care in hospital at home scheme with hospital care. Pragmatic randomised controlled trial. Leicester hospital at home scheme and the city's three acute hospitals. 199 consecutive patients referred to hospital at home by their general practitioner and assessed as being suitable for admission. Six of 102 patients randomised to hospital at home refused admission, as did 23 of 97 allocated to hospital. Hospital at home or hospital inpatient care. Mortality and change in health status (Barthel index, sickness impact profile 68, EuroQol, Philadelphia geriatric morale scale) assessed at 2 weeks and 3 months after randomisation. The main process measures were service inputs, discharge destination, readmission rates, length of initial stay, and total days of care. Hospital at home group and hospital group showed no significant differences in health status (median scores on sickness impact profile 68 were 29 and 30 respectively at 2 weeks, and 24 and 26 at 3 months) or in dependency (Barthel scores 15 and 14 at 2 weeks and 16 for both groups at 3 months). At 3 months' follow up, 26 (25%) of hospital at home group had died compared with 30 (31%) of hospital group (relative risk 0. 82 (95% confidence interval 0.52 to 1.28)). Hospital at home group required fewer days of treatment than hospital group, both in terms of initial stay (median 8 days v 14.5 days, P=0.026) and total days of care at 3 months (median 9 days v 16 days, P=0.031). Hospital at home scheme delivered care as effectively as hospital, with no clinically important differences in health status. Hospital at home resulted in significantly shorter lengths of stay, which did not lead to a higher rate of subsequent admission.

  14. An intelligent control scheme for precise tip-motion control in atomic force microscopy.

    Science.gov (United States)

    Wang, Yanyan; Hu, Xiaodong; Xu, Linyan

    2016-01-01

    The paper proposes a new intelligent control method to precisely control the tip motion of the atomic force microscopy (AFM). The tip moves up and down at a high rate along the z direction during scanning, requiring the utilization of a rapid feedback controller. The standard proportional-integral (PI) feedback controller is commonly used in commercial AFMs to enable topography measurements. The controller's response performance is determined by the set of the proportional (P) parameter and the integral (I) parameter. However, the two parameters cannot be automatically altered simultaneously according to the scanning speed and the surface topography during continuors scanning, leading to an inaccurate measurement. Thus a new intelligent controller combining the fuzzy controller and the PI controller is put forward in the paper. The new controller automatically selects the most appropriate PI parameters to achieve a fast response rate on basis of the tracking errors. In the experimental setup, the new controller is realized with a digital signal process (DSP) system, implemented in a conventional AFM system. Experiments are carried out by comparing the new method with the standard PI controller. The results demonstrate that the new method is more robust and effective for the precise tip motion control, corresponding to the achievement of a highly qualified image by shortening the response time of the controller. © Wiley Periodicals, Inc.

  15. High-order scheme for determination of a control parameter in an inverse problem from the over-specified data

    Science.gov (United States)

    Mohebbi, Akbar; Dehghan, Mehdi

    2010-12-01

    The problem of finding the solution of partial differential equations with source control parameter has appeared increasingly in physical phenomena, for example, in the study of heat conduction process, thermo-elasticity, chemical diffusion and control theory. In this paper we present a high order scheme for determining unknown control parameter and unknown solution of parabolic inverse problem with both integral overspecialization and overspecialization at a point in the spatial domain. In these equations, we first approximate the spatial derivative with a fourth order compact scheme and reduce the problem to a system of ordinary differential equations (ODEs). Then we apply a fourth order boundary value method for the solution of resulting system of ODEs. So the proposed method has fourth order accuracy in both space and time components and is unconditionally stable due to the favorable stability property of boundary value methods. Several numerical examples and also some comparisons with other methods in the literature will be investigated to confirm the efficiency of the new procedure.

  16. Dynamic output feedback control synthesis for continuous-time T-S fuzzy systems via a switched fuzzy control scheme.

    Science.gov (United States)

    Dong, Jiuxiang; Yang, Guang-Hong

    2008-08-01

    This correspondence paper is concerned with the problem of designing switched dynamic output feedback H(infinity) controllers for continuous-time Takagi-Sugeno (T-S) fuzzy systems. A new type of dynamic output feedback controllers, namely, switched dynamic parallel distributed compensation (SDPDC) controllers, is proposed, which are switched by basing on the values of membership functions. A new method for designing SDPDC controllers for guaranteeing stabilities and H(infinity) performances of closed-loop nonlinear systems is presented, where the design conditions are given in terms of the solvability of a set of linear matrix inequalities. It is shown that the new method provides better or at least the same results of the existing design methods via a pure DPDC scheme. A numerical example is given to illustrate the effectiveness of the proposed method.

  17. Study on the design schemes of the air-conditioning system in a gymnasium

    Science.gov (United States)

    Zhang, Yujin; Wu, Xinwei; Zhang, Jing; Pan, Zhixin

    2017-08-01

    In view of designing the air conditioning project for a gymnasium successfully, the cooling and heating source schemes are fully studied by analyzing the surrounding environment and energy conditions of the project, as well as the analysis of the initial investment and operating costs, which indicates the air source heat pump air conditioning system is the best choice for the project. The indoor air conditioning schemes are also studied systematically and the optimization of air conditioning schemes is carried out in each area. The principle of operating conditions for the whole year is followed and the quality of indoor air and energy-saving are ensured by the optimized design schemes, which provide references for the air conditioning system design in the same kinds of building.

  18. A practical fast acting control scheme for fuzzy logic-based voltage stabilization control

    Directory of Open Access Journals (Sweden)

    El-Kholy E.E.

    2005-01-01

    Full Text Available This paper presents a simplified control model for stabilizing a load voltage using a switched reactor in parallel with a fixed capacitor of static VAR compensator. Two IGBT’s are used to control the reactance of the switched reactor. A uniform pulse width modulation is used for controlling the two switches. The compensator has a simple control circuit and structure. A complete modeling and numerical simulation for the proposed systems are presented. A high speed Digital Signal Processor is used for implementing proportional integral (PI and fuzzy load voltage controllers. Experimental results indicate the superiority of fuzzy logic control over the conventional proportional-integral control method. Simulation results are reported and proved to be in good agreement with the relevant experimental results.

  19. A Practical Fast Acting Control Scheme For Fuzzy Logic-Based Voltage Stabilization Control

    Directory of Open Access Journals (Sweden)

    E. E. EL-Kholy

    2005-03-01

    Full Text Available This paper presents a simplified control model for stabilizing a load voltage using a switched reactor in parallel with a fixed capacitor of static VAR compensator. Two IGBT’s are used to control the reactance of the switched reactor. A uniform pulse width modulation is used for controlling the two switches. The compensator has a simple control circuit and structure. A complete modeling and numerical simulation for the proposed systems is presented. A high speed Digital Signal Processor is used for implementing proportional-integral (PI and fuzzy load voltage controllers. Experimental results indicate the superiority of fuzzy logic control over the conventional proportional-integral control method. Simulation results are reported and proved to be in good agreement with the relevant experimental results.

  20. An Improved Call Admission Control Mechanism with Prioritized Handoff Queuing Scheme for BWA Networks

    Science.gov (United States)

    Chowdhury, Prasun; Saha Misra, Iti

    2014-10-01

    Nowadays, due to increased demand for using the Broadband Wireless Access (BWA) networks in a satisfactory manner a promised Quality of Service (QoS) is required to manage the seamless transmission of the heterogeneous handoff calls. To this end, this paper proposes an improved Call Admission Control (CAC) mechanism with prioritized handoff queuing scheme that aims to reduce dropping probability of handoff calls. Handoff calls are queued when no bandwidth is available even after the allowable bandwidth degradation of the ongoing calls and get admitted into the network when an ongoing call is terminated with a higher priority than the newly originated call. An analytical Markov model for the proposed CAC mechanism is developed to analyze various performance parameters. Analytical results show that our proposed CAC with handoff queuing scheme prioritizes the handoff calls effectively and reduces dropping probability of the system by 78.57% for real-time traffic without degrading the number of failed new call attempts. This results in the increased bandwidth utilization of the network.

  1. A high-resolution gas-kinetic scheme with minimized dispersion and controllable dissipation reconstruction

    Science.gov (United States)

    Tan, Shuang; Li, QiBing

    2017-11-01

    In order to simulate multiscale problems such as turbulent flows effectively, the high-order accurate reconstruction based on mini- mized dispersion and controllable dissipation (MDCD) is implemented in the second-order accurate gas-kinetic scheme (GKS) to improve the accuracy and resolution. MDCD is firstly extended to non-uniform grids through the modification of dissipation and dispersion coefficients for uniform grids based on the local stretch ratio. Remarkable improvements in accuracy and resolution are achieved on general grids. Then a new scheme, MDCD-GKS is constructed, with the help of MDCD reconstruction, not only for conservative variables, but also for their gradients. MDCD-GKS shows good accuracy and efficiency in typical numerical tests. MDCD-GKS is also coupled with the improved delayed detached-eddy simulation (IDDES) hybrid model and applied in the fine simulation of turbulent flow around a cylinder, and the prediction is in good agreement with experiments when using the relatively coarse grid. The high accuracy and resolution of the developed GKS guarantee its high efficiency in practical applications.

  2. Speed Tracking Control of a Vehicle Robot Driver System Using Multiple Sliding Surface Control Schemes

    Directory of Open Access Journals (Sweden)

    Gang Chen

    2013-02-01

    Full Text Available To overcome the drawbacks of using a traditional proportional-integral-derivative (PID control method for a robot driver system, such as requiring preliminary offline learning, big overshoot and large speed fluctuation, a new method for speed tracking of a robot driver system based on sliding mode control is proposed in this paper. Firstly, the coordinated control model of multiple manipulators for the robot driver is built, which achieved coordinated control of the throttle mechanical leg, clutch mechanical leg, brake mechanical leg and shift mechanical arm for the robot driver. On the basis of this, a speed tracking sliding mode controller for a vehicle robot driver is designed using the method of multiple sliding surfaces design, and the variable structure control laws of throttle and brake are designed respectively, which realize the speed tracking of the given driving test cycle. Experimental results demonstrate that compared with the PID control method, the proposed method can obviously reduce the overshoot of vehicle speed tracking control and greatly improve the accuracy of vehicle speed tracking. The vehicle speed tracking accuracy stays within a tolerance band of ±2 km/h, which meets the requirements of national vehicle test standards. Furthermore, the action of the speed tracking control in the same driving test cycle using the proposed method is consistent, so that the robot driver has good repeatability. Therefore, it can ensure the effectiveness of the vehicle emission test.

  3. Definition of a Robust Supervisory Control Scheme for Sodium-Cooled Fast Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Ponciroli, R.; Passerini, S.; Vilim, R. B.

    2016-04-17

    In this work, an innovative control approach for metal-fueled Sodium-cooled Fast Reactors is proposed. With respect to the classical approach adopted for base-load Nuclear Power Plants, an alternative control strategy for operating the reactor at different power levels by respecting the system physical constraints is presented. In order to achieve a higher operational flexibility along with ensuring that the implemented control loops do not influence the system inherent passive safety features, a dedicated supervisory control scheme for the dynamic definition of the corresponding set-points to be supplied to the PID controllers is designed. In particular, the traditional approach based on the adoption of tabulated lookup tables for the set-point definition is found not to be robust enough when failures of the implemented SISO (Single Input Single Output) actuators occur. Therefore, a feedback algorithm based on the Reference Governor approach, which allows for the optimization of reference signals according to the system operating conditions, is proposed.

  4. Robust Networked Control Scheme for Distributed Secondary Control of Islanded MicroGrids

    DEFF Research Database (Denmark)

    Shafiee, Qobad; Stefanovic, Cedomir; Dragicevic, Tomislav

    2014-01-01

    couples the communication and the control functionality, such that the transmission errors are absorbed through an averaging operation performed in each local controller, resulting in a very high reliability. Furthermore, transmissions from each DG are periodic and prescheduled broadcasts, and in this way...

  5. ESTIMATION OF ACCURATE DETERMINATION FOR COORDINATES OF GRAVITY ENERGY CENTER IN COLLIMATOR TEST-OBJECT IN RESPECT OF CONTROL SCHEMES FOR OPTOELECTRONIC DEVICES WITH MATRIX PHOTODETECTORS

    Directory of Open Access Journals (Sweden)

    M. A. Starasotnikau

    2015-01-01

    Full Text Available The paper considers a control scheme of such optoelectronic devices with matrix photo-detectors as  autocollimators, microscopes, star trackers and other film equipment an d the control is carried out with the help of a collimator. A number of factors (structure discreteness, photo-detector noise, consistency in collimator test-object size, photo-detector pixel size and point scattering function of optical components exert an influence on control accuracy.In the context of control problems and alignment of optoelectronic devices the paper studies a scheme which includes two components: controlling component that is a collimator and a component to be controlled that is a tele-centric system. A mathematical model for control schemes has been proposed with the purpose to determine an effect of the above-mentioned factors and its mathematical implementation has been described in the paper.Due to simulation an optimal ratio has been selected for component parameters of the optical control scheme: point scattering function for a collimator objective and a telecentric system,  collimator test-object size, photo-detector pixel size.  A collimator test-object size has been determined in the paper. Using the considered scheme the size will give the smallest measurement error caused by photo-detector discreteness of a controlled device. A standard deviation of the gravity energy center for a collimator test-object caused by photo-detector noise has been determined in the paper. In order to reduce the effect of photo-detector noise the paper proposes to take as zero values of a signal such values which are smaller than a doubled discretization interval of an analog-to-digital converter.

  6. On the Need of Novel Medium Access Control Schemes for Network Coding enabled Wireless Mesh Networks

    DEFF Research Database (Denmark)

    Paramanathan, Achuthan; Pahlevani, Peyman; Roetter, Daniel Enrique Lucani

    2013-01-01

    This paper advocates for a new Medium Access Control (MAC) strategy for wireless meshed networks by identifying overload scenarios in order to provide additional channel access priority to the relay. The key behind our MAC protocol is that the relay will adjust its back off window size according...... that network coding will improve the throughput in such systems, but our novel medium access scheme improves the performance in the cross topology by another 66 % for network coding and 150 % for classical forwarding in theory. These gains translate in a theoretical gain of 33 % of network coding over...... classical forwarding when both systems implement the improved MAC. However, our measurement results show an even larger gain for network coding, namely, up to 65 % over forwarding, as it copes better with channel losses under high load scenarios....

  7. Performance Analysis of Savonius Rotor Based Hydropower Generation Scheme with Electronic Load Controller

    Directory of Open Access Journals (Sweden)

    Rajen Pudur

    2016-01-01

    Full Text Available This paper describes the performance of electronic load controller (ELC of asynchronous generator (AG coupled to an uncontrolled Savonius turbine and variable water velocity. An AC-DC-AC converter with a dc link capacitor is employed to maintain the required frequency. The ELC which is feeding a resistive dump load is connected in parallel with the generating system and the power consumption is varied through the duty cycle of the chopper. Gate triggering of ELC is accomplished through sinusoidal pulse width modulation (SPWM by sensing the load current. A MATLAB/Simulink model of Savonius rotor, asynchronous generator, ELC, and three-phase load is presented. The proposed scheme is tested under various load conditions under varying water velocities and the performances are observed to be satisfactory.

  8. Semiactive balancing control scheme in a rotor - bearing system supported on Mr. Dampers: design and experiments

    Energy Technology Data Exchange (ETDEWEB)

    Silva Navarro, Gerardo; Cabrera Amado, Alvaro [Cinvestav, IPN, Mexico, D.F. (Mexico)

    2007-11-15

    This paper deals with the problem of semiactive balancing control of a rotor-bearing system, where one journal bearings is supported on two radial Magneto-Rheological (MR) dampers. The mathematical model of the rotor-bearing system results from an orthotropic Jeffcott-like model and the dynamics associated to the MR dampers, whose rheological properties depend on the current inputs. For control purposes we use the Choi-Lee-Park polynomial for the MR dampers, which is quite consistent with the tpical nonlinear and complex hysteresis behavior and also simplifies the physical implementation on an experimental setup. The semiactive control scheme for the unbalance reponse of the rotor-bearing system is synthesized using sliding-mode control techniques. Some numerical and experimental results are included to illustrate the dynamic performance and robustness of the overall system. [Spanish] En este trabajo se abora el problema de control semiactivo del desbalance en un sistema rotor-chumacera, donde una de las chumaceras convencionales se monta sobre una suspension con dos amortiguadores Magneto-Reologicos (MR) radiales. El modelo matematico del sistema rotorchumacera se obtiene de un modelo tipo Jefcott ortotropico y la dinamica de los amortiguadores MR, cuyas propiedades reologicas dependen de las corrientes electricas de alimentacion. Para propositos de control se emplea el modelo polinomial de Choi-Lee-Park para los dos amortiguadores MR, el cual es consistente con el tipico comportamiento no-lineal y de histeresis, permitiendo simplificar su implementacion fisica en una plataforma experimental. El esquema de control semiactivo de la respuesta al desbalance, en el sistema rotor-chumacera, se basa en las tecnicas de control por modos deslizantes. Se presentan algunos resultados de simulacion numerica y experimentos que utilizan el funcionamiento y robustez del sistema completo.

  9. Selection with inbreeding control in simulated young bull schemes for local dairy cattle breeds.

    Science.gov (United States)

    Gandini, G; Stella, A; Del Corvo, M; Jansen, G B

    2014-03-01

    Local breeds are rarely subject to modern selection techniques; however, selection programs will be required if local breeds are to remain a viable livelihood option for farmers. Selection in small populations needs to take into account accurate inbreeding control. Optimum contribution selection (OCS) is efficient in controlling inbreeding and maximizes genetic gain. The current paper investigates genetic progress in simulated dairy cattle populations from 500 to 6,000 cows undergoing young bull selection schemes with OCS compared with truncation selection (TS) at an annual inbreeding rate of 0.003. Selection is carried out for a dairy trait with a base heritability of 0.3. A young bull selection scheme was used because of its simplicity in implementation. With TS, annual genetic gain from 0.111 standard deviation units with 500 cows increases rapidly to 0.145 standard deviation units with 4,000 cows. Then, genetic gain increases more slowly up to 6,000 cows. At the same inbreeding rate, OCS produces higher genetic progress than TS. Differences in genetic gain between OCS and TS vary from to 2 to 6.3%. Genetic gain is also improved by increasing the number of years that males can be used as sires of sires. When comparing OCS versus TS at different heritabilities, we observe an advantage of OCS only at high heritability, up to 8% with heritability of 0.9. By increasing the constraint on inbreeding, the difference of genetic gain between the 2 selection methods increases in favor of OCS, and the advantage at the inbreeding rate of 0.001 per generation is 6 times more than at the inbreeding rate of 0.003. Opportunities exist for selection even in dairy cattle populations of a few hundred females. In any case, selection in local breeds will most often require specific investments in infrastructure and manpower, including systems for accurate data recording and selection skills and the presence of artificial insemination and breeders organizations. A cost

  10. Design and implementation of adaptive PI control schemes for web tension control in roll-to-roll (R2R) manufacturing.

    Science.gov (United States)

    Raul, Pramod R; Pagilla, Prabhakar R

    2015-05-01

    In this paper, two adaptive Proportional-Integral (PI) control schemes are designed and discussed for control of web tension in Roll-to-Roll (R2R) manufacturing systems. R2R systems are used to transport continuous materials (called webs) on rollers from the unwind roll to the rewind roll. Maintaining web tension at the desired value is critical to many R2R processes such as printing, coating, lamination, etc. Existing fixed gain PI tension control schemes currently used in industrial practice require extensive tuning and do not provide the desired performance for changing operating conditions and material properties. The first adaptive PI scheme utilizes the model reference approach where the controller gains are estimated based on matching of the actual closed-loop tension control systems with an appropriately chosen reference model. The second adaptive PI scheme utilizes the indirect adaptive control approach together with relay feedback technique to automatically initialize the adaptive PI gains. These adaptive tension control schemes can be implemented on any R2R manufacturing system. The key features of the two adaptive schemes is that their designs are simple for practicing engineers, easy to implement in real-time, and automate the tuning process. Extensive experiments are conducted on a large experimental R2R machine which mimics many features of an industrial R2R machine. These experiments include trials with two different polymer webs and a variety of operating conditions. Implementation guidelines are provided for both adaptive schemes. Experimental results comparing the two adaptive schemes and a fixed gain PI tension control scheme used in industrial practice are provided and discussed. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  11. Design of a Control Scheme for Distribution Static Synchronous Compensators with Power-Quality Improvement Capability

    Directory of Open Access Journals (Sweden)

    Pedro Roncero-Sànchez

    2014-04-01

    Full Text Available Electric power systems are among the greatest achievements of the last century. Today, important issues, such as an ever-increasing demand, the flexible and reliable integration of distributed generation or a growth in disturbing loads, must be borne in mind. In this context, smart grids play a key role, allowing better efficiency of power systems. Power electronics provides solutions to the aforementioned matters, since it allows various energy sources to be integrated into smart grids. Nevertheless, the design of the various control schemes that are necessary for the correct operation of the power-electronic interface is a very important issue that must always be taken into consideration. This paper deals with the design of the control system of a distribution static synchronous compensator (DSTATCOM based on flying-capacitor multilevel converters. The control system is tailored to compensate for both voltage sags by means of reactive-power injection and voltage imbalances caused by unbalanced loads. The design of the overall control is carried out by using the root-locus and frequency-response techniques, improving both the transient response and the steady-state error of the closed-loop system. Simulation results obtained using PSCADTM/EMTDCTM (Manitoba Hydro International Ltd., Commerce Drive, Winnipeg, MB, Canada show the resultant voltage regulation.

  12. Control Scheme Formulation for the Production of Hydrogen on Demand to Feed an Internal Combustion Engine

    Directory of Open Access Journals (Sweden)

    Jarniel García Morales

    2016-12-01

    Full Text Available In this work, a control strategy is presented to produce hydrogen on demand to feed an internal combustion (IC engine. For this purpose, the modeling of the IC engine fueled by gasoline blended with 10 % v/v of anhydrous ethanol (E10 and hydrogen as an additive is developed. It is considered that the hydrogen gas is produced according to the IC engine demand, and that the hydrogen gas is obtained by an alkaline electrolyzer. The gasoline–ethanol blend added into the combustion chamber is determined according to the stoichiometric ratio and the production of hydrogen gas is regulated by a proportional and integral controller (P.I.. The controller reference is varying according to the mass flow air induced into the cylinder, in order to ensure an adequate production of hydrogen gas for any operating condition of the IC engine. The main contribution of this work is the control scheme developed, through simulation, in order to produce hydrogen on demand for any operating point of an internal combustion engine fueled by an E10 blend. The simulation results showed that the use of hydrogen gas as an additive in an E10 blend decreases the E10 fuel consumption 23 % on average, and the thermal efficiency is increased approximately 2.13 % , without brake power loss in the IC engine.

  13. The Benefits of Partnership Schemes to Schools and Research Students: A Case Study of the Researchers in Residence Scheme

    Science.gov (United States)

    Barley, Helen; Karim, Muhammed; Gilchrist, Myra; Gillies, Andrew

    2013-01-01

    To meet the needs of a modern Scottish society, a "Curriculum for Excellence" enables teachers to deliver a more coherent and skills-based curriculum, involving partnerships with external agencies. This article analyses the work of one host school/researcher team through the Researchers in Residence scheme in an Edinburgh secondary…

  14. Application of Genetic Control with Adaptive Scaling Scheme to Signal Acquisition in Global Navigation Satellite System Receiver

    Directory of Open Access Journals (Sweden)

    Ho-Nien Shou

    2012-02-01

    Full Text Available This paper presents a genetic-based control scheme that not only utilizes evolutionary characteristics to find the signal acquisition parameters, but also employs an adaptive scheme to control the search space and avoid the genetic control converging to local optimal value so as to acquire the desired signal precisely and rapidly. Simulations and experiment results show that the proposed method can improve the precision of signal parameters and take less signal acquisition time than traditional serial search methods for global navigation satellite system (GNSS signals.

  15. A Novel Rotor and Stator Magnetic Fields Direct-Orthogonalized Vector Control Scheme for the PMSM Servo System

    Directory of Open Access Journals (Sweden)

    Shi-Xiong Zhang

    2014-02-01

    Full Text Available Permanent Magnet Synchronous motor (PMSM has received widespread acceptance in recent years. In this paper, a new rotor and stator Magnetic Fields Direct-Orthogonalized Vector Control (MFDOVC scheme is proposed for PMSM servo system. This method simplified the complex calculation of traditional vector control, a part of the system resource is economized. At the same time, through the simulation illustration validation, the performance of PMSM servo system with the proposed MFDOVC scheme can achieve the same with the complex traditional vector control method, but much simpler calculation is implemented using the proposed method.

  16. A Self-Oscillating Control Scheme for a Boost Converter Providing a Controlled Output Current

    DEFF Research Database (Denmark)

    Knott, Arnold; Pfaffinger, Gerhard R.; Andersen, Michael A. E.

    2011-01-01

    Most switched mode power supplies provide a regulated voltage at their output. However, there are applications requiring a controlled current. Among others are battery chargers, test equipment for converters driven by solar cells, and LED drivers. This paper describes a dc–dc power converter real...

  17. Vector Field Driven Design for Lightweight Signal Processing and Control Schemes for Autonomous Robotic Navigation

    Directory of Open Access Journals (Sweden)

    Nebu John Mathai

    2009-01-01

    Full Text Available We address the problem of realizing lightweight signal processing and control architectures for agents in multirobot systems. Motivated by the promising results of neuromorphic engineering which suggest the efficacy of analog as an implementation substrate for computation, we present the design of an analog-amenable signal processing scheme. We use control and dynamical systems theory both as a description language and as a synthesis toolset to rigorously develop our computational machinery; these mechanisms are mated with structural insights from behavior-based robotics to compose overall algorithmic architectures. Our perspective is that robotic behaviors consist of actions taken by an agent to cause its sensory perception of the environment to evolve in a desired manner. To provide an intuitive aid for designing these behavioral primitives we present a novel visual tool, inspired vector field design, that helps the designer to exploit the dynamics of the environment. We present simulation results and animation videos to demonstrate the signal processing and control architecture in action.

  18. Vector Field Driven Design for Lightweight Signal Processing and Control Schemes for Autonomous Robotic Navigation

    Science.gov (United States)

    Mathai, Nebu John; Zourntos, Takis; Kundur, Deepa

    2009-12-01

    We address the problem of realizing lightweight signal processing and control architectures for agents in multirobot systems. Motivated by the promising results of neuromorphic engineering which suggest the efficacy of analog as an implementation substrate for computation, we present the design of an analog-amenable signal processing scheme. We use control and dynamical systems theory both as a description language and as a synthesis toolset to rigorously develop our computational machinery; these mechanisms are mated with structural insights from behavior-based robotics to compose overall algorithmic architectures. Our perspective is that robotic behaviors consist of actions taken by an agent to cause its sensory perception of the environment to evolve in a desired manner. To provide an intuitive aid for designing these behavioral primitives we present a novel visual tool, inspired vector field design, that helps the designer to exploit the dynamics of the environment. We present simulation results and animation videos to demonstrate the signal processing and control architecture in action.

  19. Formation-Based Control Scheme for Cooperative Transportation by Multiple Mobile Robots

    Directory of Open Access Journals (Sweden)

    Alpaslan Yufka

    2015-09-01

    Full Text Available This paper presents a motion-planning and control scheme for a cooperative transportation system comprising a single rigid object and multiple autonomous non-holonomic mobile robots. A leader-follower formation control strategy is used for the transportation system in which the object is assumed to be the virtual leader; the robots carrying the object are considered to be followers. A smooth trajectory between the current and desired locations of the object is generated considering the constraints of the virtual leader. In the leader-follower approach, the origin of the coordinate system attached to the centre of gravity of the object, which is known as the virtual leader, moves along the generated trajectory while the real robots, which are known as followers, maintain a desired distance and orientation in relation to the leader. An asymptotically stable tracking controller is used for trajectory tracking. The proposed approach is verified by simulations and real applications using Pioneer P3-DX mobile robots.

  20. Suitable scheme study of Chinese Building Energy Efficiency CDM Projects

    Science.gov (United States)

    Huang, Beijia; Yang, Haizhen; Wang, Shaoping; Wang, Feng

    2010-11-01

    China has great potential to develop Building Energy Efficiency Clean Development Mechanism (BEE CDM) projects, although have many challenges. Our results show that large-scale public buildings and urban residential buildings have relatively high BEE CDM potential, when comparing their characteristics to the CDM project requirements. The building enclosure, illumination energy conservation, air condition energy saving, solar thermal, and solar photovoltaic technology have relatively high application potential while considering the energy saving potential and marginal emission reduction cost. Case study of large-scale buildings shows that technology integration of building enclosure, illumination energy conservation, air condition energy saving, solar thermal can reduce required building number to 130 in order to meet the 1×105 tCO2 e/a reduction criteria. Some suggestions are also given in this paper.

  1. An Enhanced Three-Level Voltage Switching State Scheme for Direct Torque Controlled Open End Winding Induction Motor

    Science.gov (United States)

    Kunisetti, V. Praveen Kumar; Thippiripati, Vinay Kumar

    2018-01-01

    Open End Winding Induction Motors (OEWIM) are popular for electric vehicles, ship propulsion applications due to less DC link voltage. Electric vehicles, ship propulsions require ripple free torque. In this article, an enhanced three-level voltage switching state scheme for direct torque controlled OEWIM drive is implemented to reduce torque and flux ripples. The limitations of conventional Direct Torque Control (DTC) are: possible problems during low speeds and starting, it operates with variable switching frequency due to hysteresis controllers and produces higher torque and flux ripple. The proposed DTC scheme can abate the problems of conventional DTC with an enhanced voltage switching state scheme. The three-level inversion was obtained by operating inverters with equal DC-link voltages and it produces 18 voltage space vectors. These 18 vectors are divided into low and high frequencies of operation based on rotor speed. The hardware results prove the validity of proposed DTC scheme during steady-state and transients. From simulation and experimental results, proposed DTC scheme gives less torque and flux ripples on comparison to two-level DTC. The proposed DTC is implemented using dSPACE DS-1104 control board interface with MATLAB/SIMULINK-RTI model.

  2. Demand Controlled Economizer Cycles: A Direct Digital Control Scheme for Heating, Ventilating, and Air Conditioning Systems,

    Science.gov (United States)

    1984-05-01

    includes a heating coil and thermostatic control to maintain the air in this path at an elevated temperature, typically around 80 degrees Farenheit (80 F...1238 Aug 1 1236 1237 52 1074 1126 50 1033 1083 Sep 8 8 5W 862 7T 600 678 75 603 7r Oct 51 400 451 119 204 323 115 207 322 ov 64 123 287 187 71 258

  3. Optimal control, investment and utilization schemes for energy storage under uncertainty

    Science.gov (United States)

    Mirhosseini, Niloufar Sadat

    Energy storage has the potential to offer new means for added flexibility on the electricity systems. This flexibility can be used in a number of ways, including adding value towards asset management, power quality and reliability, integration of renewable resources and energy bill savings for the end users. However, uncertainty about system states and volatility in system dynamics can complicate the question of when to invest in energy storage and how best to manage and utilize it. This work proposes models to address different problems associated with energy storage within a microgrid, including optimal control, investment, and utilization. Electric load, renewable resources output, storage technology cost and electricity day-ahead and spot prices are the factors that bring uncertainty to the problem. A number of analytical methodologies have been adopted to develop the aforementioned models. Model Predictive Control and discretized dynamic programming, along with a new decomposition algorithm are used to develop optimal control schemes for energy storage for two different levels of renewable penetration. Real option theory and Monte Carlo simulation, coupled with an optimal control approach, are used to obtain optimal incremental investment decisions, considering multiple sources of uncertainty. Two stage stochastic programming is used to develop a novel and holistic methodology, including utilization of energy storage within a microgrid, in order to optimally interact with energy market. Energy storage can contribute in terms of value generation and risk reduction for the microgrid. The integration of the models developed here are the basis for a framework which extends from long term investments in storage capacity to short term operational control (charge/discharge) of storage within a microgrid. In particular, the following practical goals are achieved: (i) optimal investment on storage capacity over time to maximize savings during normal and emergency

  4. Effect of different lateral occlusion schemes on peri-implant strain: A laboratory study

    Science.gov (United States)

    Lo, Jennifer; Palamara, Joseph

    2017-01-01

    PURPOSE This study aims to investigate the effects of four different lateral occlusion schemes and different excursions on peri-implant strains of a maxillary canine implant. MATERIALS AND METHODS Four metal crowns with different occlusion schemes were attached to an implant in the maxillary canine region of a resin model. The included schemes were canine-guided (CG) occlusion, group function (GF) occlusion, long centric (LC) occlusion, and implant-protected (IP) occlusion. Each crown was loaded in three sites that correspond to maximal intercuspation (MI), 1 mm excursion, and 2 mm excursion. A load of 140 N was applied on each site and was repeated 10 times. The peri-implant strain was recorded by a rosette strain gauge that was attached on the resin model buccal to the implant. For each loading condition, the maximum shear strain value was calculated. RESULTS The different schemes and excursive positions had impact on the peri-implant strains. At MI and 1 mm positions, the GF had the least strains, followed by IP, CG, and LC. At 2 mm, the least strains were associated with GF, followed by CG, LC, and IP. However, regardless of the occlusion scheme, as the excursion increases, a linear increase of peri-implant strains was detected. CONCLUSION The peri-implant strain is susceptible to occlusal factors. The eccentric location appears to be more influential on peri-implant strains than the occlusion scheme. Therefore, adopting an occlusion scheme that can reduce the occurrence of occlusal contacts laterally may be beneficial in reducing peri-implant strains. PMID:28243391

  5. Effect of different lateral occlusion schemes on peri-implant strain: A laboratory study.

    Science.gov (United States)

    Lo, Jennifer; Abduo, Jaafar; Palamara, Joseph

    2017-02-01

    This study aims to investigate the effects of four different lateral occlusion schemes and different excursions on peri-implant strains of a maxillary canine implant. Four metal crowns with different occlusion schemes were attached to an implant in the maxillary canine region of a resin model. The included schemes were canine-guided (CG) occlusion, group function (GF) occlusion, long centric (LC) occlusion, and implant-protected (IP) occlusion. Each crown was loaded in three sites that correspond to maximal intercuspation (MI), 1 mm excursion, and 2 mm excursion. A load of 140 N was applied on each site and was repeated 10 times. The peri-implant strain was recorded by a rosette strain gauge that was attached on the resin model buccal to the implant. For each loading condition, the maximum shear strain value was calculated. The different schemes and excursive positions had impact on the peri-implant strains. At MI and 1 mm positions, the GF had the least strains, followed by IP, CG, and LC. At 2 mm, the least strains were associated with GF, followed by CG, LC, and IP. However, regardless of the occlusion scheme, as the excursion increases, a linear increase of peri-implant strains was detected. The peri-implant strain is susceptible to occlusal factors. The eccentric location appears to be more influential on peri-implant strains than the occlusion scheme. Therefore, adopting an occlusion scheme that can reduce the occurrence of occlusal contacts laterally may be beneficial in reducing peri-implant strains.

  6. A comparative study of numerical schemes and turbulence models for wind turbine aerodynamic modelling

    Energy Technology Data Exchange (ETDEWEB)

    Baxevanou, Catherine A.; Vlachos, Nicolas S.

    2004-07-01

    This paper is a comparative study of combining turbulence models and interpolation schemes to calculate turbulent flow around a NACA0012 airfoil before and after separation. The calculations were carried out using the code CAFFA of Peric, which was appropriately modified to include more numerical schemes and turbulence models. This code solves the Navier-Stokes equations for 2D incompressible flow, using finite volumes and structured, collocated, curvilinear, body fitted grids. Seven differencing schemes were investigated: central, upwind, hybrid, QUICK, Harten-Yee upwind TVD with five limiters, Roe-Sweby upwind TVD with three limiters, and Davis-Yee symmetric TVD with three limiters. Turbulence effects were incorporated using four turbulence models: standard {kappa}-{epsilon}, {kappa}-{omega} high Re with wall functions, {kappa}-{omega} high Re with integration up to the wall, and the {kappa}-{omega} low Re model. A parametric study showed that best results are obtained: a) for the {kappa}-{epsilon} model, when using the Harten-Yee upwind TVD scheme for the velocities and the upwind interpolation for the turbulence properties {kappa} and {epsilon}, and b) for the {kappa}-{omega} models, when using the Harten-Yee upwind TVD scheme with different limiters for the velocities and the turbulence quantities {kappa} and {omega}. The turbulence models that integrate up to the wall are more accurate when separation appears, while those using wall functions converge much faster. (Author)

  7. A comparative study of numerical schemes and turbulence models for wind turbine aerodynamics modelling

    Energy Technology Data Exchange (ETDEWEB)

    Baxevanou, C.A.; Vlachos, N.S.

    2004-07-01

    This paper is a comparative study of combining turbulence models and interpolation schemes to calculate turbulent flow around a NACA0012 airfoil before and after separation. The calculations were carried out using the code CAFFA of Peric, which was appropriately modified to include more numerical schemes and turbulence models. This code solves the Navier-Stokes equations for 2D incompressible flow, using finite volumes and structured, collocated, curvilinear, body fitted grids. Seven differencing schemes were investigated: central, upwind, hybrid, QUICK, Harten-Yee upwind TVD with five limiters, Roe-Sweby upwind TVD with three limiters, and Davis-Yee symmetric TVD with three limiters. Turbulence effects were incorporated using four turbulence models: standard k-{epsilon}, k-{omega} high Re with wall functions, k-{omega} high Re with integration up to the wall, and the k-{omega} low Re model. A parametric study showed that best results are obtained: a) for the k-{epsilon} model, when using the Harten-Yee upwind TVD scheme for the velocities and the upwind interpolation for the turbulence properties k and {epsilon}, and b) for the k-{omega}, models, when using the Harten-Yee upwind TVD scheme with different limiters for the velocities and the turbulence quantities k and {omega}. The turbulence models that integrate up to the wall are more accurate when separation appears, while those using wall functions converge much faster. (author)

  8. Stability of multiple access network control schemes with carrier sensing and exponential backoff

    Science.gov (United States)

    Barany, Ernest; Krupa, Maciej

    2006-05-01

    A new approach to determine the stability of multiple access network control schemes is presented. A “busy” network (the precise meaning of the term “busy” will be presented in the text) is modelled as a switched single-server hybrid dynamical system whose switching laws are stochastic and are based on typical multiple access network control protocols such as ALOHA and ethernet. The techniques are used to compute the critical ratio of traffic production per network node to total available bandwidth that ensures that data packets will not accumulate unboundedly in waiting queues at each node. This is a measure of stability of the network and is an emergent, global, property determined by decentralized, autonomous behavior of each node. The behavior of each individual node is regarded as “microscopic” and the collective behavior of the network as a whole are emergent consequences of such microscopic laws. The results follow from the stationary distribution property of ergodic Markov chains.

  9. A generalised PID-type control scheme with simple tuning for the global regulation of robot manipulators with constrained inputs

    Science.gov (United States)

    Mendoza, Marco; Zavala-Río, Arturo; Santibáñez, Víctor; Reyes, Fernando

    2015-10-01

    In this paper, a globally stabilising PID-type control scheme with a generalised saturating structure for robot manipulators under input constraints is proposed. It gives rise to various families of bounded PID-type controllers whose implementation is released from the exact knowledge of the system parameters and model structure. Compared to previous approaches of the kind, the proposed scheme is not only characterised by its generalised structure but also by its very simple tuning criterion, the simplest hitherto obtained in the considered analytical framework. Experimental results on a 3-degree-of-freedom direct-drive manipulator corroborate the efficiency of the proposed approach.

  10. Conditional selectivity performance of Indian mutual fund schemes: An empirical study

    Directory of Open Access Journals (Sweden)

    Subrata Roy

    2015-06-01

    Full Text Available The present study seeks to examine the stock-selection performance of the sample open-ended equity mutual fund schemes of Birla Sun Life Mutual Fund Company based on traditional and conditional performance measures. It is generally expected that inclusion of some relevant predetermined public information variables in the conditional CAPM provides better performance estimates as compared to the traditional measures. The study reports that after inclusion of conditioning public information variables, the selectivity performances of the schemes have dramatically improved relative to the traditional measure and also found that conditional measure is superior to traditional measure in statistical test.

  11. Study of stability of the difference scheme for the model problem of the gaslift process

    Science.gov (United States)

    Temirbekov, Nurlan; Turarov, Amankeldy

    2017-09-01

    The paper studies a model of the gaslift process where the motion in a gas-lift well is described by partial differential equations. The system describing the studied process consists of equations of motion, continuity, equations of thermodynamic state, and hydraulic resistance. A two-layer finite-difference Lax-Vendroff scheme is constructed for the numerical solution of the problem. The stability of the difference scheme for the model problem is investigated using the method of a priori estimates, the order of approximation is investigated, the algorithm for numerical implementation of the gaslift process model is given, and the graphs are presented. The development and investigation of difference schemes for the numerical solution of systems of equations of gas dynamics makes it possible to obtain simultaneously exact and monotonic solutions.

  12. A study on agent-based secure scheme for electronic medical record system.

    Science.gov (United States)

    Chen, Tzer-Long; Chung, Yu-Fang; Lin, Frank Y S

    2012-06-01

    automatically disperse arithmetic processes, and moves from one host to another in heterogeneous network systems with the characteristics of autonomy and mobility, decreasing network traffic, reducing transfer lag, encapsulating protocol, availability on heterogeneous platforms, fault-tolerance, high flexibility, and personalization. However, since a Mobile Agent contacts and exchanges information with other hosts or agents on the Internet for rapid exchange and access to medical information, the security is threatened. In order to solve the problem, this study proposes a key management scheme based on Lagrange interpolation formulas and hierarchical management structure to make Mobile Agents a more secure and efficient access control scheme for electronic patient record systems when applied to the access of patients' personal electronic patient records cross hospitals. Meanwhile, with the comparison of security and efficacy analyses being the feasibility of validation scheme and the basis of better efficiency, the security of Mobile Agents in the process of operation can be guaranteed, key management efficacy can be advanced, and the security of the Mobile Agent system can be protected.

  13. Modeling and Analysis of Resonance in LCL-Type Grid-Connected Inverters under Different Control Schemes

    Directory of Open Access Journals (Sweden)

    Yanxue Yu

    2017-01-01

    Full Text Available As a basic building block in power systems, the three-phase voltage-source inverter (VSI connects the distributed energy to the grid. For the inductor-capacitor-inductor (LCL-filter three-phase VSI, according to different current sampling position and different reference frame, there mainly exist four control schemes. Different control schemes present different impedance characteristics in their corresponding determined frequency range. To analyze the existing resonance phenomena due to the variation of grid impedances, the sequence impedance models of LCL-type grid-connected three-phase inverters under different control schemes are presented using the harmonic linearization method. The impedance-based stability analysis approach is then applied to compare the relative stability issues due to the impedance differences at some frequencies and to choose the best control scheme and the better controller parameters regulating method for the LCL-type three-phase VSI. The simulation and experiments both validate the resonance analysis results.

  14. A New Coordinated Voltage Control Scheme for Offshore AC Grid of HVDC Connected Offshore Wind Power Plants

    DEFF Research Database (Denmark)

    Sakamuri, Jayachandra N.; Cutululis, Nicolaos Antonio; Rather, Zakir Hussain

    2015-01-01

    This paper proposes a coordinated voltage control scheme (CVCS) which enhances the voltage ride through (VRT) capability of an offshore AC grid comprised of a cluster of offshore wind power plants (WPP) connected through AC cables to the offshore voltage source converter based high voltage DC (VS......V with active power balance (hence DC voltage) control assigned to the onshore converter, while frequency and AC voltage control at the offshore substation assigned to the offshore converter....

  15. VLSI IMPLEMENTATION OF NOVEL ROUND KEYS GENERATION SCHEME FOR CRYPTOGRAPHY APPLICATIONS BY ERROR CONTROL ALGORITHM

    Directory of Open Access Journals (Sweden)

    B. SENTHILKUMAR

    2015-05-01

    Full Text Available A novel implementation of code based cryptography (Cryptocoding technique for multi-layer key distribution scheme is presented. VLSI chip is designed for storing information on generation of round keys. New algorithm is developed for reduced key size with optimal performance. Error Control Algorithm is employed for both generation of round keys and diffusion of non-linearity among them. Two new functions for bit inversion and its reversal are developed for cryptocoding. Probability of retrieving original key from any other round keys is reduced by diffusing nonlinear selective bit inversions on round keys. Randomized selective bit inversions are done on equal length of key bits by Round Constant Feedback Shift Register within the error correction limits of chosen code. Complexity of retrieving the original key from any other round keys is increased by optimal hardware usage. Proposed design is simulated and synthesized using VHDL coding for Spartan3E FPGA and results are shown. Comparative analysis is done between 128 bit Advanced Encryption Standard round keys and proposed round keys for showing security strength of proposed algorithm. This paper concludes that chip based multi-layer key distribution of proposed algorithm is an enhanced solution to the existing threats on cryptography algorithms.

  16. Performance Analysis and Optimization of an Adaptive Admission Control Scheme in Cognitive Radio Networks

    Directory of Open Access Journals (Sweden)

    Shunfu Jin

    2013-01-01

    Full Text Available In cognitive radio networks, if all the secondary user (SU packets join the system without any restrictions, the average latency of the SU packets will be greater, especially when the traffic load of the system is higher. For this, we propose an adaptive admission control scheme with a system access probability for the SU packets in this paper. We suppose the system access probability is inversely proportional to the total number of packets in the system and introduce an Adaptive Factor to adjust the system access probability. Accordingly, we build a discrete-time preemptive queueing model with adjustable joining rate. In order to obtain the steady-state distribution of the queueing model exactly, we construct a two-dimensional Markov chain. Moreover, we derive the formulas for the blocking rate, the throughput, and the average latency of the SU packets. Afterwards, we provide numerical results to investigate the influence of the Adaptive Factor on different performance measures. We also give the individually optimal strategy and the socially optimal strategy from the standpoints of the SU packets. Finally, we provide a pricing mechanism to coordinate the two optimal strategies.

  17. Developing a Tool Point Control Scheme for a Hydraulic Crane Using Interactive Real-time Dynamic Simulation

    DEFF Research Database (Denmark)

    Pedersen, Mikkel Melters; Hansen, Michael Rygaard; Ballebye, Morten

    2010-01-01

    This paper describes the implementation of an interactive real-time dynamic simulation model of a hydraulic crane. The user input to the model is given continuously via joystick and output is presented continuously in a 3D animation. Using this simulation model, a tool point control scheme...... is developed for the specific crane, considering the saturation phenomena of the system and practical implementation....

  18. Acupuncture for Symptom Relief in Palliative Care—Study Protocol and Semistandardized Treatment Schemes

    Directory of Open Access Journals (Sweden)

    Sybille Kramer

    2017-08-01

    Full Text Available The use of complementary and alternative medicine methods such as acupuncture in palliative care has increased over the past years. Well-planned trials are warranted to show its effectiveness in relieving distressing symptoms. The development of treatment schemes to be used in the trial for both acupuncture and medical symptom control is challenging, as both acupuncture and palliative care are highly individualized. Thus, standardized care plans of a randomized controlled trial will have difficulties in producing treatment results that compare to the clinical practice. As an alternative, treatment protocols for both acupuncture and medical symptom control of dyspnea, pruritus, hypersalivation, depression, anxiety, and xerostomia were designed with the input of experts. They are designed to provide sufficient symptom control and comparability for a three-arm, randomized controlled trial. Medical symptom control will be provided to all groups. The two control groups will be medical treatment and sham-laser acupuncture.

  19. Acupuncture for Symptom Relief in Palliative Care-Study Protocol and Semistandardized Treatment Schemes.

    Science.gov (United States)

    Kramer, Sybille; Irnich, Dominik; Lorenzl, Stefan

    2017-08-01

    The use of complementary and alternative medicine methods such as acupuncture in palliative care has increased over the past years. Well-planned trials are warranted to show its effectiveness in relieving distressing symptoms. The development of treatment schemes to be used in the trial for both acupuncture and medical symptom control is challenging, as both acupuncture and palliative care are highly individualized. Thus, standardized care plans of a randomized controlled trial will have difficulties in producing treatment results that compare to the clinical practice. As an alternative, treatment protocols for both acupuncture and medical symptom control of dyspnea, pruritus, hypersalivation, depression, anxiety, and xerostomia were designed with the input of experts. They are designed to provide sufficient symptom control and comparability for a three-arm, randomized controlled trial. Medical symptom control will be provided to all groups. The two control groups will be medical treatment and sham-laser acupuncture. Copyright © 2017. Published by Elsevier B.V.

  20. Self-centering seismic retrofit scheme for reinforced concrete frame structures: SDOF system study

    Science.gov (United States)

    Zhang, Yunfeng; Hu, Xiaobin

    2010-06-01

    This paper presents the results of a parametric study of self-centering seismic retrofit schemes for reinforced concrete (RC) frame buildings. The self-centering retrofit system features flag-shaped hysteresis and minimal residual deformation. For comparison purpose, an alternate seismic retrofit scheme that uses a bilinear-hysteresis retrofit system such as buckling-restrained braces (BRB) is also considered in this paper. The parametric study was carried out in a single-degree-of-freedom (SDOF) system framework since a multi-story building structure may be idealized as an equivalent SDOF system and investigation of the performance of this equivalent SDOF system can provide insight into the seismic response of the multi-story building. A peak-oriented hysteresis model which can consider the strength and stiffness degradation is used to describe the hysteretic behavior of RC structures. The parametric study involves two key parameters — the strength ratio and elastic stiffness ratio between the seismic retrofit system and the original RC frame. An ensemble of 172 earthquake ground motion records scaled to the design basis earthquake in California with a probability of exceedance of 10% in 50 years was constructed for the simulation-based parametric study. The effectiveness of the two seismic retrofit schemes considered in this study is evaluated in terms of peak displacement ratio, peak acceleration ratio, energy dissipation demand ratio and residual displacement ratio between the SDOF systems with and without retrofit. It is found from this parametric study that RC structures retrofitted with the self-centering retrofit scheme (SCRS) can achieve a seismic performance level comparable to the bilinear-hysteresis retrofit scheme (BHRS) in terms of peak displacement and energy dissipation demand ratio while having negligible residual displacement after earthquake.

  1. A Multiagent System-Based Protection and Control Scheme for Distribution System With Distributed-Generation Integration

    DEFF Research Database (Denmark)

    Liu, Z.; Su, Chi; Hoidalen, Hans

    2017-01-01

    In this paper, a multi agent system (MAS) based protection and control scheme is proposed to deal with diverse operation conditions in distribution system due to distributed generation (DG) integration. Based on cooperation between DG controller and relays, an adaptive protection and control...... of system topology and DG status. The proposed scheme is tested and validated on a test distribution system in a hardware-in-the-loop real time testing platform....... algorithm is designed on converter based wind turbine DG to limit the influence of infeed fault current. With the consideration of DG control modes, an adaptive relay setting strategy is developed to help protective relays adapt suitable settings to different operation conditions caused by the variations...

  2. Satisfaction rates with the current Special Type Consultation (STC) reimbursement scheme among General Practitioners - A Mixed Methods Study.

    Science.gov (United States)

    Kiely, A; O'Meara, S; Fitzgerald, N; Regan, A M; Durcan, P; McGuire, G; Kelly, M E

    2017-03-10

    The Special Type Consultation (STC) scheme is a fee-for-service reimbursement scheme for General Practitioners (GPs) in Ireland. Introduced in 1989, the scheme includes specified patient services involving the application of a learned skill, e.g. suturing. This study aims to establish the extent to which GPs believe this scheme is appropriate for current General Practice. This is an embedded mixed-methods study combining quantitative data on GPs working experience of and qualitative data on GPs attitudes towards the scheme. Data were collected by means of an anonymous postal questionnaire. The response rate was 60.4% (n=159.) Twenty-nine percent (n=46) disagreed and 65% (n=104) strongly disagreed that the current list of special items is satisfactory. Two overriding themes were identified: economics and advancement of the STC process. This study demonstrates an overwhelming consensus among GPs that the current STC scheme is outdated and in urgent need of revision to reflect modern General Practice.

  3. Satisfaction rates with the current Special Type Consultation (STC) reimbursement scheme among General Practitioners – A Mixed Methods Study.

    LENUS (Irish Health Repository)

    Kiely, A

    2017-03-01

    The Special Type Consultation (STC) scheme is a fee-for-service reimbursement scheme for General Practitioners (GPs) in Ireland. Introduced in 1989, the scheme includes specified patient services involving the application of a learned skill, e.g. suturing. This study aims to establish the extent to which GPs believe this scheme is appropriate for current General Practice. This is an embedded mixed-methods study combining quantitative data on GPs working experience of and qualitative data on GPs attitudes towards the scheme. Data were collected by means of an anonymous postal questionnaire. The response rate was 60.4% (n=159.) Twenty-nine percent (n=46) disagreed and 65% (n=104) strongly disagreed that the current list of special items is satisfactory. Two overriding themes were identified: economics and advancement of the STC process. This study demonstrates an overwhelming consensus among GPs that the current STC scheme is outdated and in urgent need of revision to reflect modern General Practice.

  4. A study of the spreading scheme for viral marketing based on a complex network model

    Science.gov (United States)

    Yang, Jianmei; Yao, Canzhong; Ma, Weicheng; Chen, Guanrong

    2010-02-01

    Buzzword-based viral marketing, known also as digital word-of-mouth marketing, is a marketing mode attached to some carriers on the Internet, which can rapidly copy marketing information at a low cost. Viral marketing actually uses a pre-existing social network where, however, the scale of the pre-existing network is believed to be so large and so random, so that its theoretical analysis is intractable and unmanageable. There are very few reports in the literature on how to design a spreading scheme for viral marketing on real social networks according to the traditional marketing theory or the relatively new network marketing theory. Complex network theory provides a new model for the study of large-scale complex systems, using the latest developments of graph theory and computing techniques. From this perspective, the present paper extends the complex network theory and modeling into the research of general viral marketing and develops a specific spreading scheme for viral marking and an approach to design the scheme based on a real complex network on the QQ instant messaging system. This approach is shown to be rather universal and can be further extended to the design of various spreading schemes for viral marketing based on different instant messaging systems.

  5. Stabilization and analytical tuning rule of double-loop control scheme for unstable dead-time process

    Science.gov (United States)

    Ugon, B.; Nandong, J.; Zang, Z.

    2017-06-01

    The presence of unstable dead-time systems in process plants often leads to a daunting challenge in the design of standard PID controllers, which are not only intended to provide close-loop stability but also to give good performance-robustness overall. In this paper, we conduct stability analysis on a double-loop control scheme based on the Routh-Hurwitz stability criteria. We propose to use this unstable double-loop control scheme which employs two P/PID controllers to control first-order or second-order unstable dead-time processes typically found in process industries. Based on the Routh-Hurwitz stability necessary and sufficient criteria, we establish several stability regions which enclose within them the P/PID parameter values that guarantee close-loop stability of the double-loop control scheme. A systematic tuning rule is developed for the purpose of obtaining the optimal P/PID parameter values within the established regions. The effectiveness of the proposed tuning rule is demonstrated using several numerical examples and the result are compared with some well-established tuning methods reported in the literature.

  6. Adaptive Training of Manual Control: 1. Comparison of Three Adaptive Variables and Two Logic Schemes.

    Science.gov (United States)

    Norman, D. A.; And Others

    "Machine controlled adaptive training is a promising concept. In adaptive training the task presented to the trainee varies as a function of how well he performs. In machine controlled training, adaptive logic performs a function analogous to that performed by a skilled operator." This study looks at the ways in which gain-effective time…

  7. Impact of various emission control schemes on air quality using WRF-Chem during APEC China 2014

    Science.gov (United States)

    Guo, Jianping; He, Jing; Liu, Hongli; Miao, Yucong; Liu, Huan; Zhai, Panmao

    2016-09-01

    Emission control measures have been implemented to make air quality good enough for Asia-Pacific Economic Cooperation (APEC) China 2014, which provides us with an ideal test-bed to determine how these measures affect air quality in Beijing and surrounding areas. Based on hourly observations at eight monitoring sites of Beijing, the concentrations of other primary atmospheric pollutants during APEC were found to have significantly lower magnitudes than those before APEC, with the exception of a higher O3 concentration. Overall, WRF/Chem reproduced the observed time series of PM2.5, PM10, NO2, CO, and O3 notably well. To investigate the impact of emission control measures on air quality on both local and regional scales, four emission control schemes were developed according to the locations where emission reduction had taken place; the corresponding simulations were subsequently run separately. Scheme S2 (emission control implemented in Beijing) resulted in reductions of 22%, 24%, 10% and 22% for the concentrations of PM2.5, PM10, NO2 and CO, respectively, compared with 14%, 14%, 8%, and 13% for scheme S3 (emission controls implemented from outside of Beijing). This finding indicates that the local emission reduction in Beijing contributes more to the improved air quality in Beijing during APEC China 2014 than does the emission reduction from outside of Beijing. In terms of the impact on the regional scale, the real emission control scheme led to significant reduction of PM2.5 throughout the whole domain. Although the regional impact cannot be completely ignored, both emission reduction measures implemented in Beijing and those implemented outside of Beijing favor greater reduction in PM2.5 in the domains where measurements are presumably taken, as compared with other domains. Therefore, to improve the air quality in Beijing, more coordinated efforts should be made, particularly in the aspect of more stringent reduction and control strategies on pollutant emission

  8. An Enhanced Droop Control Scheme for Resilient Active Power Sharing in Paralleled Two-Stage PV Inverter Systems

    DEFF Research Database (Denmark)

    Liu, Hongpeng; Yang, Yongheng; Wang, Xiongfei

    2016-01-01

    generation) due to the intermittency. In that case, unbalance in active power generation may occur among the paralleled systems. Additionally, most droop-controlled systems have been assumed to be a single dc-ac inverter with a fixed dc input source. The dc-dc converter as the front-end of a two-stage...... photovoltaic (PV) system has not been considered. In this paper, an enhanced droop scheme is thus proposed to address those issues, and the proposed scheme can enable resilient active power sharing in parallel two-stage PV inverter systems. Furthermore, a small-signal analysis for the proposed droop control......Traditional droop-controlled systems assume that the generators are able to provide sufficient power as required. This is however not always true, especially in renewable systems, where the energy sources (e.g., photovoltaic source) may not be able to provide enough power (or even loss of power...

  9. Active defense scheme against DDoS based on mobile agent and network control in network confrontation

    Science.gov (United States)

    Luo, Rong; Li, Junshan; Ye, Xia; Wang, Rui

    2013-03-01

    In order to effective defend DDoS attacks in network confrontation, an active defense scheme against DDoS is built based on Mobile Agent and network control. A distributed collaborative active defense model is constructed by using mobile agent technology and encapsulating a variety of DDoS defense techniques. Meanwhile the network control theory is applied to establish a network confrontation's control model for DDoS to control the active defense process. It provides a new idea to solve the DDoS problem.

  10. Coordinated Control Scheme of Battery Energy Storage System (BESS) and Distributed Generations (DGs) for Electric Distribution Grid Operation

    DEFF Research Database (Denmark)

    Cha, Seung-Tae; Zhao, Haoran; Wu, Qiuwei

    2012-01-01

    This paper describes a coordinated control scheme of battery energy storage system (BESS) and distributed generations (DGs) for electric distribution grid operation. The BESS is designed to stabilize frequency and voltages as a primary control after the electric distribution system enters...... into the islanding operation mode, while the centralized joint load frequency control (CJLFC) utilizing DGs handles the secondary frequency regulation. The BESS with the associated controllers has been modelled in Real-time digital simulator (RTDS) in order to identify the improvement of the frequency and voltage...

  11. The Multiple Sclerosis Risk Sharing Scheme Monitoring Study – early results and lessons for the future

    Directory of Open Access Journals (Sweden)

    Chilcott James B

    2009-01-01

    Full Text Available Abstract Background Risk sharing schemes represent an innovative and important approach to the problems of rationing and achieving cost-effectiveness in high cost or controversial health interventions. This study aimed to assess the feasibility of risk sharing schemes, looking at long term clinical outcomes, to determine the price at which high cost treatments would be acceptable to the NHS. Methods This case study of the first NHS risk sharing scheme, a long term prospective cohort study of beta interferon and glatiramer acetate in multiple sclerosis (MS patients in 71 specialist MS centres in UK NHS hospitals, recruited adults with relapsing forms of MS, meeting Association of British Neurologists (ABN criteria for disease modifying therapy. Outcome measures were: success of recruitment and follow up over the first three years, analysis of baseline and initial follow up data and the prospect of estimating the long term cost-effectiveness of these treatments. Results Centres consented 5560 patients. Of the 4240 patients who had been in the study for a least one year, annual review data were available for 3730 (88.0%. Of the patients who had been in the study for at least two years and three years, subsequent annual review data were available for 2055 (78.5% and 265 (71.8% patients respectively. Baseline characteristics and a small but statistically significant progression of disease were similar to those reported in previous pivotal studies. Conclusion Successful recruitment, follow up and early data analysis suggest that risk sharing schemes should be able to deliver their objectives. However, important issues of analysis, and political and commercial conflicts of interest still need to be addressed.

  12. Voltage Control Scheme with Distributed Generation and Grid Connected Converter in a DC Microgrid

    OpenAIRE

    Jong-Chan Choi; Ho-Yong Jeong; Jin-Young Choi; Dong-Jun Won; Seon-Ju Ahn; Seung-il Moon

    2014-01-01

    Direct Current (DC) microgrids are expected to become larger due to the rapid growth of DC energy sources and power loads. As the scale of the system expends, the importance of voltage control will be increased to operate power systems stably. Many studies have been performed on voltage control methods in a DC microgrid, but most of them focused only on a small scale microgrid, such as a building microgrid. Therefore, a new control method is needed for a middle or large scale DC microgrid. T...

  13. Cap and trade schemes on waste management: A case study of the Landfill Allowance Trading Scheme (LATS) in England

    Energy Technology Data Exchange (ETDEWEB)

    Calaf-Forn, Maria, E-mail: mcalaf@ent.cat [Institut de Ciència i Tecnologia Ambientals (ICTA), Universitat Autònoma de Barcelona (UAB), E-08193 Bellaterra, Barcelona (Spain); ENT Environment and Management, Carrer Sant Joan 39, First Floor, E-08800 Vilanova i la Geltrú, Barcelona (Spain); Roca, Jordi [Departament de Teoria Econòmica, Universitat de Barcelona (UB), Diagonal, 696, E-08034 Barcelona (Spain); Puig-Ventosa, Ignasi [ENT Environment and Management, Carrer Sant Joan 39, First Floor, E-08800 Vilanova i la Geltrú, Barcelona (Spain)

    2014-05-01

    Highlights: • LATS has been effective to achieve a reduction of the amount of landfilled waste. • LATS has been one of the few environmental instruments for waste management with a cap and trade methodology. • LATS has achieved to increase recycling of the biodegradable and other waste fractions. - Abstract: The Landfill Allowance Trading Scheme (LATS) is one of the main instruments used in England to enforce the landfill diversion targets established in the Directive 1999/31/EC of the European Parliament and of the Council of 26 April 1999 on the landfill of waste (Landfill Directive). Through the LATS, biodegradable municipal waste (BMW) allowances for landfilling are allocated to each local authority, otherwise known as waste disposal authorities (WDAs). The quantity of landfill allowances received is expected to decrease continuously from 2005/06 to 2019/20 so as to meet the objectives of the Landfill Directive. To achieve their commitments, WDAs can exchange, buy, sell or transfer allowances among each other, or may re-profile their own allocation through banking and/or borrowing. Despite the goals for the first seven years – which included two target years (2005/06 and 2009/10) – being widely achieved (the average allocation of allowances per WDA was 22.9% higher than those finally used), market activity among WDAs was high and prices were not very stable. Results in terms of waste reduction and recycling levels have been satisfactory. The reduction of BMW landfilled (in percentage) was higher during the first seven years of the LATS period (2005/06–2011/12) (around 7% annually) than during the previous period (2001/02–2004/05) (4.2% annually). Since 2008, the significance of the LATS diminished because of an increase in the rate of the UK Landfill Tax. The LATS was suppressed after the 2012/13 target year, before what it was initially scheduled. The purpose of this paper is to describe the particularities of the LATS, analyse its performance as

  14. Developing Efficient Coordination Schemes to Control Over-Pumping in the Heihe River Basin, China

    Science.gov (United States)

    Pedrazzini, G.

    2015-12-01

    Many wicked water resources problems are approached in a social planner perspective. This not always matches the real institutional and policy-making context, where, rather, multiple decision-makers (DMs) can act independently, or weakly cooperate, ultimately producing system-wide inefficient trade-offs. The idea in this work is to adopt a more realistic approach, where the multi-DMs nature of the problem is preserved and the uncoordinated DMs are driven, thorough coordination mechanisms, towards a more system-wide efficient solution. An agent-based modelling framework linked to a surface and groundwater model is used to design these coordination mechanisms as constraints to the independent agents (i.e., DMs) behaviour. In the Heihe Basin the ongoing introduction of smart meter IC-card systems on farmers' pumping wells will soon allow monitoring and control of abstractions with the goal of preventing further depletion of the resource. The major interest of policy makers in the region concerns the development of new and the improvement of existing legislation on pricing schemes and/or groundwater quotas. The model outcome where agents act rationally but selfishly is compared to the optimal solution at system-level assuming perfect coordination and cooperation. The optimal solutions with respect to the given utility functions are computed using nonlinear optimization with a rolling out time horizon. The Pareto-Frontier is synthesized through an exhaustive sampling of the weight coefficient space and related to the current and to the historical management of the last 4 decades. The best parameter values for the proposed coordination mechanisms are determined and the alternatives are compared with respect to their efficiency and acceptability. Preliminary results suggest that a regulatory tax on groundwater of about a factor 10 of the current resource fee is required to increase the elasticity of the groundwater demand curve such that reducing consumption becomes

  15. Controlled retransmission scheme for prioritized burst segmentation to support quality-of-service in optical burst switching networks

    Science.gov (United States)

    Hou, Rui; He, Tingting; Mao, Tengyue

    2012-10-01

    In optical burst switching (OBS) networks, burst contentions in OBS core nodes may cause data loss. To reduce this data loss, a retransmission scheme has been applied. However, uncontrolled retransmission may significantly increase network load and data loss probability, thus defeating the retransmission purpose. In addition, in a priority traffic existing OBS network, OBS nodes may apply different retransmission mechanisms to priority bursts for quality-of-service (QoS) support. We present a controlled retransmission scheme for prioritized burst segmentation to support QoS in OBS networks. Different from previous work in the literature, we set a different value to retransmission probability at each contention and propose a retransmission analytical model for a burst segmentation contention resolution scheme. In addition, we apply the proposed retransmission scheme to the prioritized burst segmentation for QoS support. We take into account the load at each link due to both the fresh and the retransmitted traffic and calculate the path-blocking probability and the byte loss probability for high-priority and low-priority bursts to evaluate the network performance. An extensive simulation is proposed to validate our analytical model.

  16. SCHEME (Soft Control Human error Evaluation MEthod) for advanced MCR HRA

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Inseok; Jung, Wondea [KAERI, Daejeon (Korea, Republic of); Seong, Poong Hyun [KAIST, Daejeon (Korea, Republic of)

    2015-05-15

    The Technique for Human Error Rate Prediction (THERP), Korean Human Reliability Analysis (K-HRA), Human Error Assessment and Reduction Technique (HEART), A Technique for Human Event Analysis (ATHEANA), Cognitive Reliability and Error Analysis Method (CREAM), and Simplified Plant Analysis Risk Human Reliability Assessment (SPAR-H) in relation to NPP maintenance and operation. Most of these methods were developed considering the conventional type of Main Control Rooms (MCRs). They are still used for HRA in advanced MCRs even though the operating environment of advanced MCRs in NPPs has been considerably changed by the adoption of new human-system interfaces such as computer-based soft controls. Among the many features in advanced MCRs, soft controls are an important feature because the operation action in NPP advanced MCRs is performed by soft controls. Consequently, those conventional methods may not sufficiently consider the features of soft control execution human errors. To this end, a new framework of a HRA method for evaluating soft control execution human error is suggested by performing the soft control task analysis and the literature reviews regarding widely accepted human error taxonomies. In this study, the framework of a HRA method for evaluating soft control execution human error in advanced MCRs is developed. First, the factors which HRA method in advanced MCRs should encompass are derived based on the literature review, and soft control task analysis. Based on the derived factors, execution HRA framework in advanced MCRs is developed mainly focusing on the features of soft control. Moreover, since most current HRA database deal with operation in conventional type of MCRs and are not explicitly designed to deal with digital HSI, HRA database are developed under lab scale simulation.

  17. An Optimal Integrated Control Scheme for Permanent Magnet Synchronous Generator-Based Wind Turbines under Asymmetrical Grid Fault Conditions

    Directory of Open Access Journals (Sweden)

    Dan Wang

    2016-04-01

    Full Text Available In recent years, the increasing penetration level of wind energy into power systems has brought new issues and challenges. One of the main concerns is the issue of dynamic response capability during outer disturbance conditions, especially the fault-tolerance capability during asymmetrical faults. In order to improve the fault-tolerance and dynamic response capability under asymmetrical grid fault conditions, an optimal integrated control scheme for the grid-side voltage-source converter (VSC of direct-driven permanent magnet synchronous generator (PMSG-based wind turbine systems is proposed in this paper. The optimal control strategy includes a main controller and an additional controller. In the main controller, a double-loop controller based on differential flatness-based theory is designed for grid-side VSC. Two parts are involved in the design process of the flatness-based controller: the reference trajectories generation of flatness output and the implementation of the controller. In the additional control aspect, an auxiliary second harmonic compensation control loop based on an improved calculation method for grid-side instantaneous transmission power is designed by the quasi proportional resonant (Quasi-PR control principle, which is able to simultaneously restrain the second harmonic components in active power and reactive power injected into the grid without the respective calculation for current control references. Moreover, to reduce the DC-link overvoltage during grid faults, the mathematical model of DC-link voltage is analyzed and a feedforward modified control factor is added to the traditional DC voltage control loop in grid-side VSC. The effectiveness of the optimal control scheme is verified in PSCAD/EMTDC simulation software.

  18. Public vs private administration of rural health insurance schemes: a comparative study in Zhejiang of China.

    Science.gov (United States)

    Zhou, Xiaoyuan; Mao, Zhengzhong; Rechel, Bernd; Liu, Chaojie; Jiang, Jialin; Zhang, Yinying

    2013-07-01

    Since 2003, China has experimented in some of the country's counties with the private administration of the New Cooperative Medical Scheme (NCMS), a publicly subsidized health insurance scheme for rural populations. Our study compared the effectiveness and efficiency of private vs public administration in four counties in one of China's most affluent provinces in the initial stage of the NCMS's implementation. The study was undertaken in Ningbo city of Zhejiang province. Out of 10 counties in Ningbo, two counties with private administration for the NCMS (Beilun and Ninghai) were compared with two others counties with public administration (Zhenhai and Fenghua), using the following indicators: (1) proportion of enrollees who were compensated for inpatient care; (2) average reimbursement-expense ratio per episode of inpatient care; (3) overall administration cost; (4) enrollee satisfaction. Data from 2004 to 2006 were collected from the local health authorities, hospitals and the contracted insurance companies, supplemented by a randomized household questionnaire survey covering 176 households and 479 household members. In our sample counties, private administration of the NCMS neither reduced transaction costs, nor improved the benefits of enrollees. Enrollees covered by the publicly administered NCMS were more likely to be satisfied with the insurance scheme than those covered by the privately administered NCMS. Experience in the selected counties suggests that private administration of the NCMS did not deliver the hoped-for results. We conclude that caution needs to be exercised in extending private administration of the NCMS.

  19. A comparative study of European insurance schemes for extreme weather risks and incentives for risk reduction

    Science.gov (United States)

    de Ruiter, Marleen; Hudson, Paul; de Ruig, Lars; Kuik, Onno; Botzen, Wouter

    2017-04-01

    This paper provides an analysis of the insurance schemes that cover extreme weather events in twelve different EU countries and the risk reduction incentives offered by these schemes. Economic impacts of extreme weather events in many regions in Europe and elsewhere are on the rise due to climate change and increasing exposure as driven by urban development. In an attempt to manage impacts from extreme weather events, natural disaster insurance schemes can provide incentives for taking measures that limit weather-related risks. Insurance companies can influence public risk management policies and risk-reducing behaviour of policyholders by "rewarding behaviour that reduces risks and potential damages" (Botzen and Van den Bergh, 2008, p. 417). Examples of insurance market systems that directly or indirectly aim to incentivize risk reduction with varying degrees of success are: the U.S. National Flood Insurance Programme; the French Catastrophes Naturelles system; and the U.K. Flood Re program which requires certain levels of protection standards for properties to be insurable. In our analysis, we distinguish between four different disaster types (i.e. coastal and fluvial floods, droughts and storms) and three different sectors (i.e. residential, commercial and agriculture). The selected case studies also provide a wide coverage of different insurance market structures, including public, private and public-private insurance provision, and different methods of coping with extreme loss events, such as re-insurance, governmental aid and catastrophe bonds. The analysis of existing mechanisms for risk reduction incentives provides recommendations about incentivizing adaptive behaviour, in order to assist policy makers and other stakeholders in designing more effective insurance schemes for extreme weather risks.

  20. A quantitative study on factors influencing enrolment of dairy farmers in a community health insurance scheme.

    Science.gov (United States)

    Greef, Tineke de Groot-de; Monareng, Lydia V; Roos, Janetta H

    2016-12-09

    Access to affordable and effective health care is a challenge in low- and middle- income countries. Out-of-pocket expenditure for health care is a major cause of impoverishment. One way to facilitate access and overcome catastrophic expenditure is through a health insurance mechanism, whereby risks are shared and financial inputs pooled by way of contributions. This study examined factors that influenced the enrolment status of dairy farmers in Western Kenya to a community health insurance (CHI) scheme. Quantitative, cross-sectional research was used to describe factors influencing the enrolment in the CHI scheme. Quota and convenience sampling was used, recruiting a sample of 135 farmers who supply milk to a dairy cooperation. Data were collected using a structured interview schedule and analysed using Stata SE, Data Analysis and Statistical Software, Version 12. Factors influencing non-enrolment were identified as affordability (40%; n = 47), unfamiliarity with the management of the scheme (37%; n = 44) and a lack of understanding about the scheme (41%; n = 48). An exploratory factor analysis was used to reduce the variables to two factors: information provision and understanding community health insurance (CHI). Logistic regression identified factors associated with enrolment in the Tanykina Community Healthcare Plan (TCHP). Supplies of less than six litres of milk per day (OR: 0.22; 95% CI: 0.06-0.84) and information provision (OR: 8.77; 95% CI: 2.25-34.16) were significantly associated with enrolment in the TCHP. Nearly 30% (29.6%; n = 40) of the respondents remarked that TCHP is expensive and 17% (n = 23) asked for more education on CHI and TCHP in an open-ended question. Recommendations related to marketing strategies, financial approach, information provision and further research were outlined to be made to the management of the TCHP as well as to those involved in public health.

  1. An Empirical Study on User-oriented Association Analysis of Library Classification Schemes

    Directory of Open Access Journals (Sweden)

    Hsiao-Tieh Pu

    2002-12-01

    Full Text Available Library classification schemes are mostly organized based on disciplines with a hierarchical structure. From the user point of view, some highly related yet non-hierarchical classes may not be easy to perceive in these schemes. This paper is to discover hidden associations between classes by analyzing users’ usage of library collections. The proposed approach employs collaborative filtering techniques to discover associated classes based on the circulation patterns of similar users. Many associated classes scattered across different subject hierarchies could be discovered from the circulation patterns of similar users. The obtained association norms between classes were found to be useful in understanding users' subject preferences for a given class. Classification schemes can, therefore, be made more adaptable to changes of users and the uses of different library collections. There are implications for applications in information organization and retrieval as well. For example, catalogers could refer to the ranked associated classes when they perform multi-classification, and users could also browse the associated classes for related subjects in an enhanced OPAC system. In future research, more empirical studies will be needed to validate the findings, and methods for obtaining user-oriented associations can still be improved.[Article content in Chinese

  2. APC-PC Combined Scheme in Gilbert Two State Model: Proposal and Study

    Science.gov (United States)

    Bulo, Yaka; Saring, Yang; Bhunia, Chandan Tilak

    2017-04-01

    In an automatic repeat request (ARQ) scheme, a packet is retransmitted if it gets corrupted due to transmission errors caused by the channel. However, an erroneous packet may contain both erroneous bits and correct bits and hence it may still contain useful information. The receiver may be able to combine this information from multiple erroneous copies to recover the correct packet. Packet combining (PC) is a simple and elegant scheme of error correction in transmitted packet, in which two received copies are XORed to obtain the bit location of erroneous bits. Thereafter, the packet is corrected by bit inversion of bit located as erroneous. Aggressive packet combining (APC) is a logic extension of PC primarily designed for wireless communication with objective of correcting error with low latency. PC offers higher throughput than APC, but PC does not correct double bit errors if occur in same bit location of erroneous copies of the packet. A hybrid technique is proposed to utilize the advantages of both APC and PC while attempting to remove the limitation of both. In the proposed technique, applications of APC-PC on Gilbert two state model has been studied. The simulation results show that the proposed technique offers better throughput than the conventional APC and lesser packet error rate than PC scheme.

  3. Shamir secret sharing scheme with dynamic access structure (SSSDAS). Case study on nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Thiyagarajan, P.; Thandra, Prasanth Kumar; Rajan, J.; Satyamurthy, S.A.V. [Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam (India). Computer Div.; Aghila, G. [National Institute of Technology, Karaikal (India). Dept. of Computer Science and Engineering

    2015-05-15

    In recent years, due to the sophistication offered by the Internet, strategic organizations like nuclear power plants are linked to the outside world communication through the Internet. The entry of outside world communication into strategic organization (nuclear power plant) increases the hacker's attempts to crack its security and to trace any information which is being sent among the top level officials. Information security system in nuclear power plant is very crucial as even small loophole in the security system will lead to a major disaster. Recent cyber attacks in nuclear power plant provoked information security professionals to look deeply into the information security aspects of strategic organizations (nuclear power plant). In these lines, Shamir secret sharing scheme with dynamic access structure (SSSDAS) is proposed in the paper which provides enhanced security by providing dynamic access structure for each node in different hierarchies. The SSSDAS algorithm can be applied to any strategic organizations with hierarchical structures. In this paper the possible scenarios where SSSDAS algorithm can be applied to nuclear power plant is explained as a case study. The proposed SSSDAS scheme identifies the wrong shares, if any, used for reconstruction of the secret. The SSSDAS scheme also address the three major security parameters namely confidentiality, authentication and integrity.

  4. Comparative Study between Two Market Clearing Schemes in Wind Dominant Electricity Markets

    DEFF Research Database (Denmark)

    Farashbashi-Astaneh, Seyed-Mostafa; Hu, Weihao; Chen, Zhe

    2015-01-01

    . According to the proposed agent-based approach, electricity market agents (here generation units) learn from their previous bidding experience to obtain maximum financial. A comparative study is then conducted to investigate the impact of mentioned pricing schemes on price volatility and average price level......High price volatility and excessive price reduction are introduced as two emerging problems in wind dominant electricity markets. In this study, an agent-based simulation methodology is employed to investigate the impact of two pricing mechanisms, uniform and pay-as-bid, on the mentioned problems...

  5. F2AC: A Lightweight, Fine-Grained, and Flexible Access Control Scheme for File Storage in Mobile Cloud Computing

    Directory of Open Access Journals (Sweden)

    Wei Ren

    2016-01-01

    Full Text Available Current file storage service models for cloud servers assume that users either belong to single layer with different privileges or cannot authorize privileges iteratively. Thus, the access control is not fine-grained and flexible. Besides, most access control methods at cloud servers mainly rely on computationally intensive cryptographic algorithms and, especially, may not be able to support highly dynamic ad hoc groups with addition and removal of group members. In this paper, we propose a scheme called F2AC, which is a lightweight, fine-grained, and flexible access control scheme for file storage in mobile cloud computing. F2AC can not only achieve iterative authorization, authentication with tailored policies, and access control for dynamically changing accessing groups, but also provide access privilege transition and revocation. A new access control model called directed tree with linked leaf model is proposed for further implementations in data structures and algorithms. The extensive analysis is given for justifying the soundness and completeness of F2AC.

  6. The FODA-TDMA satellite access scheme - Presentation, study of the system, and results

    Science.gov (United States)

    Celandroni, Nedo; Ferro, Erina

    1991-12-01

    A description is given of FODA-TDMA, a satellite access scheme designed for mixed traffic. The study of the system is presented and the choice of some parameters is justified. A simplified analytic solution is found, describing the steady-state behavior of the system. Some results of the simulation tests for an already existing hardware environment are also presented for the channel speeds of 2 and 8 Mb/s, considering both the stationary and the transient cases. The results of the experimentation at 2 Mb/s on the satellite Eutelsat-F2 are also presented and compared with the results of the simulation.

  7. Hybrid ARQ Error-Controlling Scheme for Robust and Efficient Transmission of UWB Body Area Networks

    Science.gov (United States)

    Suzuki, Haruka; Hernandez, Marco; Kohno, Ryuji

    This paper presents hybrid type-II automatic repeat request (H-ARQ) for wireless wearable body area networks (BANs) based on ultra wideband (UWB) technology. The proposed model is based on three schemes, namely, high rate optimized rate compatible punctured convolutional codes (HRO-RCPC), Reed Solomon (RS) invertible codes and their concatenation. Forward error correction (FEC) coding is combined with simple cyclic redundancy check (CRC) error detection. The performance is investigated for two channels: CM3 (on-body to on-body) and CM4 (on-body to a gateway) scenarios of the IEEE802.15.6 BAN channel models for BANs. It is shown that the improvement in performance in terms of throughput and error protection robustness is very significant. Thus, the proposed H-ARQ schemes can be employed and optimized to suit medical and non-medical applications. In particular we propose the use of FEC coding for non-medical applications as those require less stringent quality of service (QoS), while the incremental redundancy and ARQ configuration is utilized only for medical applications. Thus, higher QoS is guaranteed for medical application of BANs while allowing coexistence with non-medical applications.

  8. The CATFISH study protocol: an evaluation of a water fluoridation scheme.

    Science.gov (United States)

    Goodwin, Michaela; Emsley, Richard; Kelly, Michael; Rooney, Eric; Sutton, Matthew; Tickle, Martin; Wagstaff, Rebecca; Walsh, Tanya; Whittaker, William; Pretty, Iain A

    2016-02-01

    Tooth decay is the commonest disease of childhood. We have known for over 90 years that fluoride can prevent tooth decay; it is present in nearly all toothpastes and can be provided in mouthwashes, gels and varnishes. The oldest method of applying fluoride is via the water supply at a concentration of 1 part per million. The two most important reviews of water fluoridation in the United Kingdom (the York Review and MRC Report on water fluoridation and health) concluded that whilst there was evidence to suggest water fluoridation provided a benefit in caries reduction, there was a need to improve the evidence base in several areas. This study will use a natural experiment to assess the incidence of caries in two geographical areas, one in which the water supply is returned to being fluoridated following a discontinuation of fluoridation and one that continues to have a non-fluoridated water supply. The oral health of two discrete study populations will be evaluated - those born 9 months after the water fluoridation was introduced, and those who were in their 1st year of school after the introduction of fluoridated water. Both populations will be followed prospectively for 5 years using a census approach in the exposed group along with matched numbers recruitment in a non-exposed control. Parents of the younger cohort will complete questionnaires every 6 months with child clinical examination at ages 3 and 5, whilst the older cohort will have clinical examinations only, at approximately 5, 7 and 11 years old. This project provides a unique opportunity to conduct a high quality evaluation of the reintroduction of a water fluoridation scheme, which satisfies the inclusion criteria stipulated by the York systematic review and can address the design issues identified in the MRC report. The research will make a major contribution to the understanding of the costs and effects of water fluoridation in the UK in the 21st Century. Its findings will help inform UK policy on

  9. A Model Reference Adaptive Control/PID Compound Scheme on Disturbance Rejection for an Aerial Inertially Stabilized Platform

    Directory of Open Access Journals (Sweden)

    Xiangyang Zhou

    2016-01-01

    Full Text Available This paper describes a method to suppress the effect of nonlinear and time-varying mass unbalance torque disturbance on the dynamic performances of an aerial inertially stabilized platform (ISP. To improve the tracking accuracy and robustness of the ISP, a compound control scheme based on both of model reference adaptive control (MRAC and PID control methods is proposed. The dynamic model is first developed which reveals the unbalance torque disturbance with the characteristic of being nonlinear and time-varying. Then, the MRAC/PID compound controller is designed, in which the PID parameters are adaptively adjusted based on the output errors between the reference model and the actual system. In this way, the position errors derived from the prominent unbalance torque disturbance are corrected in real time so that the tracking accuracy is improved. To verify the method, the simulations and experiments are, respectively, carried out. The results show that the compound scheme has good ability in mass unbalance disturbance rejection, by which the system obtains higher stability accuracy compared with the PID method.

  10. Impact of invitation schemes on breast cancer screening coverage: A cohort study from Copenhagen, Denmark.

    Science.gov (United States)

    Jacobsen, Katja Kemp; von Euler Chelpin, My; Vejborg, Ilse; Lynge, Elsebeth

    2017-03-01

    Background The purpose of mammography screening is to decrease breast cancer mortality. To achieve this a high coverage by examination is needed. Within an organized screening programme, we examined the impact of changes in the invitation schedule on the interplay between coverage and participation. Method We studied nine cohorts aged 50-51 when first targeted by mammography screening in Copenhagen, Denmark. Population data were retrieved from the Danish Civil Registration System; invitation and attendance data from the screening programme database. Data were linked using unique personal identification numbers. Coverage by invitation was defined as (number of invited women/number of targeted women), coverage by examination as (number of screened women/number of targeted women), and participation rate as (number of screened women/number of invited women). Results Coverage by invitation was close to or above 95% for all newly recruited cohorts. In subsequent invitation rounds, both technical errors and changes in the invitation scheme affected the coverage by invitation. Coverage by examination at first invitation was 72.5% for the first cohort, but dropped to 64.2% for the latest cohort. Furthermore, coverage by examination dropped by increasing invitation number and with omission of re-invitation of previous non-attenders. Participation rate closely reflected changes in the invitation scheme. Conclusion Changes in the invitation schemes influenced coverage by invitation, coverage by examination, and participation rate. We observed a considerable gap between coverage by examination and participation rate, strongly indicating that the latter cannot without reservations, be taken as an indicator of the first.

  11. Water management for controlling the breeding of Anopheles mosquitoes in rice irrigation schemes in Kenya

    DEFF Research Database (Denmark)

    Mutero, C M; Blank, H; Konradsen, F

    2000-01-01

    between the 4th and 1st instar larvae in the subplots was only 0.08, indicating very low survival rates. In contrast, the 4th/1st instar ratio for subplots with other water management regimes ranged between 0.27 and 0.68, suggesting a correspondingly higher survival than observed with intermittent...... differences among subplots with different water regimes. The average yield per hectare ranged from 4.8-5.3 metric tonnes. The average daily water percolation/seepage rate was 3.6 mm and did not significantly differ among different water management regimes. Further research is necessary to, among other things......An experiment to assess the impact of intermittent irrigation on Anopheles larval populations, rice yields and water use was conducted in the Mwea rice irrigation scheme in Kenya. Four water regimes including intermittent irrigation were tested in a complete randomized block experimental design...

  12. A Control Chart for Gamma Distributed Variables Using Repetitive Sampling Scheme

    OpenAIRE

    Nasrullah Khan; Muhammad Aslam; Liaquat Ahmad; Chi-Hyuck Jun

    2017-01-01

    In this manuscript, a control chart is designed when the quality characteristic of interest follows a gamma distribution using repetitive sampling. The Wilson-Hilferty approximation is used to transform the gamma distributed characteristic to a normal random variable. Two pairs of control limits are established and their control constants are determined by considering the specified in-control average run length (ARL). The out-of-control ARL is derived when the process is shifted in terms of t...

  13. Effectiveness and cost-effectiveness of a physical activity loyalty scheme for behaviour change maintenance: a cluster randomised controlled trial.

    Science.gov (United States)

    Hunter, Ruth F; Brennan, Sarah F; Tang, Jianjun; Smith, Oliver J; Murray, Jennifer; Tully, Mark A; Patterson, Chris; Longo, Alberto; Hutchinson, George; Prior, Lindsay; French, David P; Adams, Jean; McIntosh, Emma; Kee, Frank

    2016-07-22

    Increasing physical activity in the workplace can provide employee physical and mental health benefits, and employer economic benefits through reduced absenteeism and increased productivity. The workplace is an opportune setting to encourage habitual activity. However, there is limited evidence on effective behaviour change interventions that lead to maintained physical activity. This study aims to address this gap and help build the necessary evidence base for effective, and cost-effective, workplace interventions. This cluster randomised control trial will recruit 776 office-based employees from public sector organisations in Belfast and Lisburn city centres, Northern Ireland. Participants will be randomly allocated by cluster to either the Intervention Group or Control Group (waiting list control). The 6-month intervention consists of rewards (retail vouchers, based on similar principles to high street loyalty cards), feedback and other evidence-based behaviour change techniques. Sensors situated in the vicinity of participating workplaces will promote and monitor minutes of physical activity undertaken by participants. Both groups will complete all outcome measures. The primary outcome is steps per day recorded using a pedometer (Yamax Digiwalker CW-701) for 7 consecutive days at baseline, 6, 12 and 18 months. Secondary outcomes include health, mental wellbeing, quality of life, work absenteeism and presenteeism, and use of healthcare resources. Process measures will assess intervention "dose", website usage, and intervention fidelity. An economic evaluation will be conducted from the National Health Service, employer and retailer perspective using both a cost-utility and cost-effectiveness framework. The inclusion of a discrete choice experiment will further generate values for a cost-benefit analysis. Participant focus groups will explore who the intervention worked for and why, and interviews with retailers will elucidate their views on the sustainability

  14. Effectiveness and cost-effectiveness of a physical activity loyalty scheme for behaviour change maintenance: a cluster randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Ruth F. Hunter

    2016-07-01

    Full Text Available Abstract Background Increasing physical activity in the workplace can provide employee physical and mental health benefits, and employer economic benefits through reduced absenteeism and increased productivity. The workplace is an opportune setting to encourage habitual activity. However, there is limited evidence on effective behaviour change interventions that lead to maintained physical activity. This study aims to address this gap and help build the necessary evidence base for effective, and cost-effective, workplace interventions. Methods/design This cluster randomised control trial will recruit 776 office-based employees from public sector organisations in Belfast and Lisburn city centres, Northern Ireland. Participants will be randomly allocated by cluster to either the Intervention Group or Control Group (waiting list control. The 6-month intervention consists of rewards (retail vouchers, based on similar principles to high street loyalty cards, feedback and other evidence-based behaviour change techniques. Sensors situated in the vicinity of participating workplaces will promote and monitor minutes of physical activity undertaken by participants. Both groups will complete all outcome measures. The primary outcome is steps per day recorded using a pedometer (Yamax Digiwalker CW-701 for 7 consecutive days at baseline, 6, 12 and 18 months. Secondary outcomes include health, mental wellbeing, quality of life, work absenteeism and presenteeism, and use of healthcare resources. Process measures will assess intervention “dose”, website usage, and intervention fidelity. An economic evaluation will be conducted from the National Health Service, employer and retailer perspective using both a cost-utility and cost-effectiveness framework. The inclusion of a discrete choice experiment will further generate values for a cost-benefit analysis. Participant focus groups will explore who the intervention worked for and why, and interviews with

  15. A Muscle Synergy-inspired Adaptive Control Scheme for a Hybrid Walking Neuroprosthesis

    Directory of Open Access Journals (Sweden)

    Naji A Alibeji

    2015-12-01

    Full Text Available Abstract--- Abstract--- A hybrid neuroprosthesis that uses an electric motor-based wearable exoskeleton and functional electrical stimulation (FES has a promising potential to restore walking in persons with paraplegia. A hybrid actuation structure introduces effector redundancy, making its automatic control a challenging task because multiple muscles and additional electric motor need to be coordinated. Inspired by the muscle synergy principle, we designed a low dimensional controller to control multiple effectors: FES of multiple muscles and electric motors. The resulting control system may be less complex and easier to control. To obtain the muscle synergy-inspired low dimensional control, a subject-specific gait model was optimized to compute optimal control signals for the multiple effectors. The optimal control signals were then dimensionally reduced by using principal component analysis to extract synergies. Then, an adaptive feedforward controller with an update law for the synergy activation was designed. In addition, feedback control was used to provide stability and robustness to the control design. The adaptive-feedforward and feedback control structure makes the low dimensional controller more robust to disturbances and variations in the model parameters and may help to compensate for other time-varying phenomena (e.g., muscle fatigue. This is proven by using a Lyapunov stability analysis, which yielded semi-global uniformly ultimately bounded tracking. Computer simulations were performed to test the new controller on a 4 degree of freedom gait model.

  16. A Muscle Synergy-Inspired Adaptive Control Scheme for a Hybrid Walking Neuroprosthesis.

    Science.gov (United States)

    Alibeji, Naji A; Kirsch, Nicholas Andrew; Sharma, Nitin

    2015-01-01

    A hybrid neuroprosthesis that uses an electric motor-based wearable exoskeleton and functional electrical stimulation (FES) has a promising potential to restore walking in persons with paraplegia. A hybrid actuation structure introduces effector redundancy, making its automatic control a challenging task because multiple muscles and additional electric motor need to be coordinated. Inspired by the muscle synergy principle, we designed a low dimensional controller to control multiple effectors: FES of multiple muscles and electric motors. The resulting control system may be less complex and easier to control. To obtain the muscle synergy-inspired low dimensional control, a subject-specific gait model was optimized to compute optimal control signals for the multiple effectors. The optimal control signals were then dimensionally reduced by using principal component analysis to extract synergies. Then, an adaptive feedforward controller with an update law for the synergy activation was designed. In addition, feedback control was used to provide stability and robustness to the control design. The adaptive-feedforward and feedback control structure makes the low dimensional controller more robust to disturbances and variations in the model parameters and may help to compensate for other time-varying phenomena (e.g., muscle fatigue). This is proven by using a Lyapunov stability analysis, which yielded semi-global uniformly ultimately bounded tracking. Computer simulations were performed to test the new controller on a 4-degree of freedom gait model.

  17. Direct aerosol chemical composition measurements to evaluate the physicochemical differences between controlled sea spray aerosol generation schemes

    Science.gov (United States)

    Collins, D. B.; Zhao, D. F.; Ruppel, M. J.; Laskina, O.; Grandquist, J. R.; Modini, R. L.; Stokes, M. D.; Russell, L. M.; Bertram, T. H.; Grassian, V. H.; Deane, G. B.; Prather, K. A.

    2014-11-01

    Controlled laboratory studies of the physical and chemical properties of sea spray aerosol (SSA) must be under-pinned by a physically and chemically accurate representation of the bubble-mediated production of nascent SSA particles. Bubble bursting is sensitive to the physico-chemical properties of seawater. For a sample of seawater, any important differences in the SSA production mechanism are projected into the composition of the aerosol particles produced. Using direct chemical measurements of SSA at the single-particle level, this study presents an intercomparison of three laboratory-based, bubble-mediated SSA production schemes: gas forced through submerged sintered glass filters ("frits"), a pulsed plunging-waterfall apparatus, and breaking waves in a wave channel filled with natural seawater. The size-resolved chemical composition of SSA particles produced by breaking waves is more similar to particles produced by the plunging waterfall than those produced by sintered glass filters. Aerosol generated by disintegrating foam produced by sintered glass filters contained a larger fraction of organic-enriched particles and a different size-resolved elemental composition, especially in the 0.8-2 μm dry diameter range. Interestingly, chemical differences between the methods only emerged when the particles were chemically analyzed at the single-particle level as a function of size; averaging the elemental composition of all particles across all sizes masked the differences between the SSA samples. When dried, SSA generated by the sintered glass filters had the highest fraction of particles with spherical morphology compared to the more cubic structure expected for pure NaCl particles produced when the particle contains relatively little organic carbon. In addition to an intercomparison of three SSA production methods, the role of the episodic or "pulsed" nature of the waterfall method on SSA composition was under-taken. In organic-enriched seawater, the continuous

  18. Multi-agent system-based event-triggered hybrid control scheme for energy internet

    DEFF Research Database (Denmark)

    Dou, Chunxia; Yue, Dong; Han, Qing Long

    2017-01-01

    This paper is concerned with an event-triggered hybrid control for the energy Internet based on a multi-agent system approach with which renewable energy resources can be fully utilized to meet load demand with high security and well dynamical quality. In the design of control, a multi-agent system...... of event-triggered hybrid control strategies whereby the multi-agent system implements the hierarchical hybrid control to achieve multiple control objectives. Finally, the effectiveness of the proposed control is validated by means of simulation results....

  19. A Comparative Study of Different Reconstruction Schemes for a Reconstructed Discontinuous Galerkin Method on Arbitrary Grids

    Energy Technology Data Exchange (ETDEWEB)

    Hong Luo; Hanping Xiao; Robert Nourgaliev; Chunpei Cai

    2011-06-01

    A comparative study of different reconstruction schemes for a reconstruction-based discontinuous Galerkin, termed RDG(P1P2) method is performed for compressible flow problems on arbitrary grids. The RDG method is designed to enhance the accuracy of the discontinuous Galerkin method by increasing the order of the underlying polynomial solution via a reconstruction scheme commonly used in the finite volume method. Both Green-Gauss and least-squares reconstruction methods and a least-squares recovery method are implemented to obtain a quadratic polynomial representation of the underlying discontinuous Galerkin linear polynomial solution on each cell. These three reconstruction/recovery methods are compared for a variety of compressible flow problems on arbitrary meshes to access their accuracy and robustness. The numerical results demonstrate that all three reconstruction methods can significantly improve the accuracy of the underlying second-order DG method, although the least-squares reconstruction method provides the best performance in terms of both accuracy and robustness.

  20. Study on the structure optimization scheme design of a double-tube once-through steam

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Xinyu; Wu, Shifa; Wang, Pengfei; Zhao, Fuyu [Dept. of Nuclear Science and Technology, Xi' an Jiaotong University, Xi' an (China)

    2016-08-15

    A double-tube once-through steam generator (DOTSG) consisting of an outer straight tube and an inner helical tube is studied in this work. First, the structure of the DOTSG is optimized by considering two different objective functions. The tube length and the total pressure drop are considered as the first and second objective functions, respectively. Because the DOTSG is divided into the subcooled, boiling, and superheated sections according to the different secondary fluid states, the pitches in the three sections are defined as the optimization variables. A multi-objective optimization model is established and solved by particle swarm optimization. The optimization pitch is small in the subcooled region and superheated region, and large in the boiling region. Considering the availability of the optimum structure at power levels below 100% full power, we propose a new operating scheme that can fix the boundaries between the three heat-transfer sections. The operation scheme is proposed on the basis of data for full power, and the operation parameters are calculated at low power level. The primary inlet and outlet temperatures, as well as flow rate and secondary outlet temperature are changed according to the operation procedure.

  1. Visceral Leishmaniasis on the Indian Subcontinent: Modelling the Dynamic Relationship between Vector Control Schemes and Vector Life Cycles.

    Directory of Open Access Journals (Sweden)

    David M Poché

    2016-08-01

    Full Text Available Visceral leishmaniasis (VL is a disease caused by two known vector-borne parasite species (Leishmania donovani, L. infantum, transmitted to man by phlebotomine sand flies (species: Phlebotomus and Lutzomyia, resulting in ≈50,000 human fatalities annually, ≈67% occurring on the Indian subcontinent. Indoor residual spraying is the current method of sand fly control in India, but alternative means of vector control, such as the treatment of livestock with systemic insecticide-based drugs, are being evaluated. We describe an individual-based, stochastic, life-stage-structured model that represents a sand fly vector population within a village in India and simulates the effects of vector control via fipronil-based drugs orally administered to cattle, which target both blood-feeding adults and larvae that feed on host feces.Simulation results indicated efficacy of fipronil-based control schemes in reducing sand fly abundance depended on timing of drug applications relative to seasonality of the sand fly life cycle. Taking into account cost-effectiveness and logistical feasibility, two of the most efficacious treatment schemes reduced population peaks occurring from April through August by ≈90% (applications 3 times per year at 2-month intervals initiated in March and >95% (applications 6 times per year at 2-month intervals initiated in January relative to no control, with the cumulative number of sand fly days occurring April-August reduced by ≈83% and ≈97%, respectively, and more specifically during the summer months of peak human exposure (June-August by ≈85% and ≈97%, respectively.Our model should prove useful in a priori evaluation of the efficacy of fipronil-based drugs in controlling leishmaniasis on the Indian subcontinent and beyond.

  2. [Study on optimizing the reimbursement scheme under the New Rural Cooperative Medical System, based on Monte Carlo simulation].

    Science.gov (United States)

    Meng, Xuehui; Huang, Yixiang; Wu, Shaolong; Liu, Qing

    2014-06-01

    To explore the application of Monte Carlo simulation in optimizing and adjusting the reimbursement scheme with regard to the New Rural Cooperative Medical System (NCMS) to scientific steering practice. Optimization of the reimbursement scheme in rural areas of China was also studied. A multi-stage sampling household survey was conducted in Sihui county, with 4 433 rural residents from 1 179 households from 13 towns in Guangdong province surveyed by self-designed questionnaire. Probit Regression Model was applied in fitting data and then estimating the own-price elasticity and cross elasticity of healthcare demand for both outpatients and inpatients. Monte Carlo simulation model was constructed to estimate the reimbursement effects of various alternative reimbursement schemes, by replicated simulation for one thousand times and each sampling on five hundred households. In this way, optimization of the implemented reimbursement scheme in Sihui county was conducted. Own-priced elasticity of demands for outpatient visit, inpatient visit in the township hospital center, secondary hospital and tertiary hospital were -0.174, -0.264, -0.675 and -0.429, respectively. Outpatient demand was affected by the per-visit price of township hospital center and secondary hospital. The cross-priced elasticity of demands for outpatient visit appeared to be 0.125 and 0.150. The reimbursement effects of Scheme B7 showed that the efficiency of NCMS fund was 17.85% , the reimbursement ratio for healthcare was 25.63%, and the decreased percentages of poverty caused by illness was 18.25%, more than 9.37%, from the implemented scheme A. So the implemented scheme was in need for optimization. Monte Carlo simulation technique was applicable to simulate the effects of the optimized alternative reimbursement scheme of NCMS and it provided a new idea and method to optimize and adjust the reimbursement scheme.

  3. Sensitivity study of the wet deposition schemes in the modelling of the Fukushima accident.

    Science.gov (United States)

    Quérel, Arnaud; Quélo, Denis; Roustan, Yelva; Mathieu, Anne; Kajino, Mizuo; Sekiyama, Thomas; Adachi, Kouji; Didier, Damien; Igarashi, Yasuhito

    2016-04-01

    The Fukushima-Daiichi release of radioactivity is a relevant event to study the atmospheric dispersion modelling of radionuclides. Actually, the atmospheric deposition onto the ground may be studied through the map of measured Cs-137 established consecutively to the accident. The limits of detection were low enough to make the measurements possible as far as 250km from the nuclear power plant. This large scale deposition has been modelled with the Eulerian model ldX. However, several weeks of emissions in multiple weather conditions make it a real challenge. Besides, these measurements are accumulated deposition of Cs-137 over the whole period and do not inform of deposition mechanisms involved: in-cloud, below-cloud, dry deposition. A comprehensive sensitivity analysis is performed in order to understand wet deposition mechanisms. It has been shown in a previous study (Quérel et al, 2016) that the choice of the wet deposition scheme has a strong impact on the assessment of the deposition patterns. Nevertheless, a "best" scheme could not be highlighted as it depends on the selected criteria: the ranking differs according to the statistical indicators considered (correlation, figure of merit in space and factor 2). A possibility to explain the difficulty to discriminate between several schemes was the uncertainties in the modelling, resulting from the meteorological data for instance. Since the move of the plume is not properly modelled, the deposition processes are applied with an inaccurate activity in the air. In the framework of the SAKURA project, an MRI-IRSN collaboration, new meteorological fields at higher resolution (Sekiyama et al., 2013) were provided and allows to reconsider the previous study. An updated study including these new meteorology data is presented. In addition, a focus on several releases causing deposition in located areas during known period was done. This helps to better understand the mechanisms of deposition involved following the

  4. Time-Varying Scheme for Non-Centralized Model Predictive Control of Large-scale Systems

    NARCIS (Netherlands)

    Nunez Vicencio, A.A.; Ocampo-Martinez, C.; Maestre, J.M.; De Schutter, B.H.K.

    2015-01-01

    The Non-Centralized Model Predictive Control (NC-MPC) framework refers in this paper to any distributed, hierarchical, or decentralized model predictive controller (or a combination of them) the structure of which can change over time and the control actions of which are not obtained based on a

  5. 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....

  6. Factors affecting participation in group agri-environment schemes: a case study of the Dartmoor Commons

    OpenAIRE

    Willcocks, Ann

    2017-01-01

    Environmental stewardship schemes are an important driver of biodiversity and habitat improvement throughout England, with the provision of funding to land managers to deliver effective land management that will benefit wildlife, habitats, natural resources and the population. Participation in agri-environment schemes is voluntary and much is done to encourage scheme participation. Dartmoor is a designated landscape, a National Park, and a Special Area of Conservation and encompasses areas...

  7. The influence of wearing schemes and supportive telephone calls on adherence in accelerometry measurement: results of a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    van den Berg N

    2017-03-01

    Full Text Available Neeltje van den Berg,1,2 Sabina Ulbricht,2,3 Thea Schwaneberg,1,2 Kerstin Weitmann,1,2 Franziska Weymar,1–3 Stefan Groß,2,4 Marcus Dörr,2,4 Wolfgang Hoffmann1,2 1Institute for Community Medicine, University Medicine Greifswald, 2German Centre for Cardiovascular Research (DZHK, Partner Site Greifswald, 3Institute of Social Medicine and Prevention, University Medicine Greifswald, 4Department of Internal Medicine B, University Medicine Greifswald, Greifswald, Germany Background: Physical activity (PA can be assessed by accelerometer monitors. However, a high adherence to wearing this device is essential to obtain valid data. In this study, the influence of different wearing schemes and additional supportive phone calls (SPCs on adherence was examined. Methods: A randomized study with four groups was conducted in the context of a health examination program among participants aged 40–75 years without a history of cardiovascular diseases. Participants were recruited in different settings (general medical practices, job center, and health insurance. The participants were asked to wear an accelerometer for 7 consecutive days according to the wearing scheme “day and night” or “day only” and received or did not receive SPCs. Full adherence was defined as a total wearing time of 98 hours (between 8 am and 10 pm during 7 days. A generalized linear model was used to calculate the difference between the maximum possible and the observed adherence. Results: Adherence could be assessed for 249 participants (mean age: 56.40 years; standard deviation [SD] 9.83, 40% males. The mean wearing time was 84.04 hours (SD 20.75. Participants with the wearing scheme day and night were significantly more adherent than participants with the wearing scheme day only (incidence rate ratio [IRR] 0.63; P=0.005. SPCs had no additional effect on adherence (IRR 0.80; P=0.168. Conclusion: To assess PA, the wearing scheme day and night provides the best possible

  8. An Effective Massive Sensor Network Data Access Scheme Based on Topology Control for the Internet of Things.

    Science.gov (United States)

    Yi, Meng; Chen, Qingkui; Xiong, Neal N

    2016-11-03

    This paper considers the distributed access and control problem of massive wireless sensor networks' data access center for the Internet of Things, which is an extension of wireless sensor networks and an element of its topology structure. In the context of the arrival of massive service access requests at a virtual data center, this paper designs a massive sensing data access and control mechanism to improve the access efficiency of service requests and makes full use of the available resources at the data access center for the Internet of things. Firstly, this paper proposes a synergistically distributed buffer access model, which separates the information of resource and location. Secondly, the paper divides the service access requests into multiple virtual groups based on their characteristics and locations using an optimized self-organizing feature map neural network. Furthermore, this paper designs an optimal scheduling algorithm of group migration based on the combination scheme between the artificial bee colony algorithm and chaos searching theory. Finally, the experimental results demonstrate that this mechanism outperforms the existing schemes in terms of enhancing the accessibility of service requests effectively, reducing network delay, and has higher load balancing capacity and higher resource utility rate.

  9. An Effective Massive Sensor Network Data Access Scheme Based on Topology Control for the Internet of Things

    Directory of Open Access Journals (Sweden)

    Meng Yi

    2016-11-01

    Full Text Available This paper considers the distributed access and control problem of massive wireless sensor networks’ data access center for the Internet of Things, which is an extension of wireless sensor networks and an element of its topology structure. In the context of the arrival of massive service access requests at a virtual data center, this paper designs a massive sensing data access and control mechanism to improve the access efficiency of service requests and makes full use of the available resources at the data access center for the Internet of things. Firstly, this paper proposes a synergistically distributed buffer access model, which separates the information of resource and location. Secondly, the paper divides the service access requests into multiple virtual groups based on their characteristics and locations using an optimized self-organizing feature map neural network. Furthermore, this paper designs an optimal scheduling algorithm of group migration based on the combination scheme between the artificial bee colony algorithm and chaos searching theory. Finally, the experimental results demonstrate that this mechanism outperforms the existing schemes in terms of enhancing the accessibility of service requests effectively, reducing network delay, and has higher load balancing capacity and higher resource utility rate.

  10. Players and processes behind the national health insurance scheme: a case study of Uganda.

    Science.gov (United States)

    Basaza, Robert K; O'Connell, Thomas S; Chapčáková, Ivana

    2013-09-22

    Uganda is the last East African country to adopt a National Health Insurance Scheme (NHIS). To lessen the inequitable burden of healthcare spending, health financing reform has focused on the establishment of national health insurance. The objective of this research is to depict how stakeholders and their power and interests have shaped the process of agenda setting and policy formulation for Uganda's proposed NHIS. The study provides a contextual analysis of the development of NHIS policy within the context of national policies and processes. The methodology is a single case study of agenda setting and policy formulation related to the proposed NHIS in Uganda. It involves an analysis of the real-life context, the content of proposals, the process, and a retrospective stakeholder analysis in terms of policy development. Data collection comprised a literature review of published documents, technical reports, policy briefs, and memos obtained from Uganda's Ministry of Health and other unpublished sources. Formal discussions were held with ministry staff involved in the design of the scheme and some members of the task force to obtain clarification, verify events, and gain additional information. The process of developing the NHIS has been an incremental one, characterised by small-scale, gradual changes and repeated adjustments through various stakeholder engagements during the three phases of development: from 1995 to 1999; 2000 to 2005; and 2006 to 2011. Despite political will in the government, progress with the NHIS has been slow, and it has yet to be implemented. Stakeholders, notably the private sector, played an important role in influencing the pace of the development process and the currently proposed design of the scheme. This study underscores the importance of stakeholder analysis in major health reforms. Early use of stakeholder analysis combined with an ongoing review and revision of NHIS policy proposals during stakeholder discussions would be an

  11. A Control Chart for Gamma Distributed Variables Using Repetitive Sampling Scheme

    Directory of Open Access Journals (Sweden)

    Nasrullah Khan

    2017-03-01

    Full Text Available In this manuscript, a control chart is designed when the quality characteristic of interest follows a gamma distribution using repetitive sampling. The Wilson-Hilferty approximation is used to transform the gamma distributed characteristic to a normal random variable. Two pairs of control limits are established and their control constants are determined by considering the specified in-control average run length (ARL. The out-of-control ARL is derived when the process is shifted in terms of the scale parameter of the Gamma distribution. The ARLs are presented for various values of the shape parameter according to process shift parameters. A simulated example is given to illustrate the proposed control chart.

  12. A self-coordinating adaptive control scheme for HVDC transmission systems

    Energy Technology Data Exchange (ETDEWEB)

    Meah, Kala [Electrical and Computer Engineering, York College of Pennsylvania, York, PA (United States); Sadrul Ula, A.H.M. [Electrical and Computer Engineering, University of Wyoming, Laramie, WY (United States)

    2009-11-15

    The transients in a HVDC system can temporarily change line currents, voltages, and power substantially from the reference steady state values and the behavior of the system depends greatly upon the parameters of the converter controller. The DC system performances are affected by the AC system characteristics such as the short circuit ratio, and the AC system inertia. A controller which has good performance for a particular operating condition may not have sufficiently good performance under another operating condition or vice versa. Performance of the controller also depends on the impedance at the rectifier and the inverter bus, which may vary according to the operating conditions of the AC network. A controller with self-coordinating adaptive capability can perform better in various situations. The proposed controller is tested at a very low SCR, the most critical value for system performance evaluation, and at the low inertia of the AC system. Simulation results are compared between proposed controller, fuzzy tuned controller, gain scheduling controller, and fixed-parameter controller. All simulations are conducted using MATLAB/SIMULINK software package. (author)

  13. A Rate Control Scheme of the Even Low Bit-Rate Video Encoder

    OpenAIRE

    Bing Zhou; Shi-Mei Su; Xingjin Zhang; Xiaoqiang Li

    2009-01-01

    Rate control plays an important role in transmitting low-delay and high-quality images over the channel of very low bandwidth. The rate control algorithm in MPEG-4 or H.26X only defined the rate control model of P-frame, and did not introduce the rate control model of I-frame as it supposed that only the first frame is an I-frame, the others are all P-frames. However, in practical applications, a certain number of I-frames have to be inserted to meet the demand for fault-tolerant transmission...

  14. Chaos suppression via observer based active control scheme: Application to Duffing's oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar-Lopez, Ricardo [Departamento de Energia, Universidad Autonoma Metropolita-Azcapotzalco, Av. San Pablo No. 180, Reynosa-Tamaulipas, Azcapotzalco 02200, Mexico DF (Mexico)]. E-mail: raguilar@correo.azc.uam.mx; Martinez-Guerra, Rafael [Departamento de Control Automatico, CINVESTAV-IPN, C.P. 07360 Mexico DF (Mexico)

    2007-06-15

    The aim of this paper is the synthesis of a robust control law for chaos suppression of a class of non-linear oscillator with affine control input. A robust state observer based active controller, which provides robustness against model uncertainties and noisy output measurements is proposed. The closed-loop stability for the underlying closed-loop system is done via the regulation and estimation errors dynamics. The performance of the proposed control law is illustrated with numerical simulations. The method is general and can be applied to various non-linear systems which satisfy the conditions required.

  15. Second Order Sliding Mode Control Scheme for an Autonomous Underwater Vehicle with Dynamic Region Concept

    Directory of Open Access Journals (Sweden)

    Zool H. Ismail

    2015-01-01

    Full Text Available The main goal in developing closed loop control system for an Autonomous Underwater Vehicle (AUV is to make a robust vehicle from natural and exogenous perturbations such as wind, wave, and ocean currents. However a well-known robust control, for instance, Sliding Mode Controller (SMC, gives a chattering effect and it influences the stability of an AUV. Furthermore, some researchers combined other controls to get better result but it tends to present long computational time and causes large energy consumption. Thus, this paper proposed a Super Twisting Sliding Mode Controller (STSMC with dynamic region concept for an AUV. STSMC or a second order SMC is adopted as a robust controller which is free from chattering effect. Meanwhile, the implementation of dynamic region is useful to reduce the energy usage. As a result, the proposed controller obtains global asymptotic stability which is validated by using Lyapunov-like function. Moreover, some simulations present the efficiency of proposed controller. In conclusion, STSMC with region based control is effective to be applied for the robust tracking of an AUV. It contributes to give a fast response when handling the perturbations, short computational time, and low energy demand.

  16. An on-line equivalent system identification scheme for adaptive control. Ph.D. Thesis - Stanford Univ.

    Science.gov (United States)

    Sliwa, S. M.

    1984-01-01

    A prime obstacle to the widespread use of adaptive control is the degradation of performance and possible instability resulting from the presence of unmodeled dynamics. The approach taken is to explicitly include the unstructured model uncertainty in the output error identification algorithm. The order of the compensator is successively increased by including identified modes. During this model building stage, heuristic rules are used to test for convergence prior to designing compensators. Additionally, the recursive identification algorithm as extended to multi-input, multi-output systems. Enhancements were also made to reduce the computational burden of an algorithm for obtaining minimal state space realizations from the inexact, multivariate transfer functions which result from the identification process. A number of potential adaptive control applications for this approach are illustrated using computer simulations. Results indicated that when speed of adaptation and plant stability are not critical, the proposed schemes converge to enhance system performance.

  17. Phonon impact on optical control schemes of quantum dots: Role of quantum dot geometry and symmetry

    Science.gov (United States)

    Lüker, S.; Kuhn, T.; Reiter, D. E.

    2017-12-01

    Phonons strongly influence the optical control of semiconductor quantum dots. When modeling the electron-phonon interaction in several theoretical approaches, the quantum dot geometry is approximated by a spherical structure, though typical self-assembled quantum dots are strongly lens-shaped. By explicitly comparing simulations of a spherical and a lens-shaped dot using a well-established correlation expansion approach, we show that, indeed, lens-shaped dots can be exactly mapped to a spherical geometry when studying the phonon influence on the electronic system. We also give a recipe to reproduce spectral densities from more involved dots by rather simple spherical models. On the other hand, breaking the spherical symmetry has a pronounced impact on the spatiotemporal properties of the phonon dynamics. As an example we show that for a lens-shaped quantum dot, the phonon emission is strongly concentrated along the direction of the smallest axis of the dot, which is important for the use of phonons for the communication between different dots.

  18. Multi-agent system-based event-triggered hybrid control scheme for energy internet

    DEFF Research Database (Denmark)

    Dou, Chunxia; Yue, Dong; Han, Qing Long

    2017-01-01

    This paper is concerned with an event-triggered hybrid control for the energy Internet based on a multi-agent system approach with which renewable energy resources can be fully utilized to meet load demand with high security and well dynamical quality. In the design of control, a multi-agent system...

  19. Evaluation of Linear and Non-Linear Control Schemes Applied to a Hydraulic Servo System

    DEFF Research Database (Denmark)

    Andersen, Torben Ole; Hansen, Michael Rygaard; Pedersen, Henrik Clemmensen

    2005-01-01

    Due to the innovation of low-cost electronics such as sensors, microcontrollers etc., the focus on highperformance motion control is increasing. This work focuses on position control of single-input single-output hydraulic servo-systems in general. A hydraulically actuated robotic manipulator...

  20. A Microprocessor-Based Control, Scheme for a PWM Voltage-Fed ...

    African Journals Online (AJOL)

    In this paper, the flexibility of programmed control logic is exploited in the close loop control of a PWM thyristor voltage fed inverter supplying an induction heating tank load. The microprocessor ... the microprocessor unit. Illustrative steady state and transient circuit of an experimental model of the induction heater are given.

  1. Inner-Learning Mechanism Based Control Scheme for Manipulator with Multitasking and Changing Load

    Directory of Open Access Journals (Sweden)

    Fangzheng Xue

    2014-05-01

    Full Text Available With the rapid development of robot technology and its application, manipulators may face complex tasks and dynamic environments in the coming future, which leads to two challenges of control: multitasking and changing load. In this paper, a novel multicontroller strategy is presented to meet such challenges. The presented controller is composed of three parts: subcontrollers, inner-learning mechanism, and switching rules. Each subcontroller is designed with self-learning skills to fit the changing load under a special task. When a new task comes, switching rule reselects the most suitable subcontroller as the working controller to handle current task instead of the older one. Inner-learning mechanism makes the subcontrollers learn from the working controller when load changes so that the switching action causes smaller tracking error than the traditional switch controller. The results of the simulation experiments on two-degree manipulator show the proposed method effect.

  2. Feasibility tests of a new all-digital beam control scheme for LEIR

    CERN Document Server

    Angoletta, Maria Elena; Findlay, A; Pedersen, F; CERN. Geneva. AB Department

    2004-01-01

    The new Low Energy Ion Ring (LEIR), to be commissioned at CERN in early 2005, will be a very important element of the LHC lead ions injection chain and will require a new beam control and cavity servoing system. Current plans call for a new all-digital beam control system based on the same technology deployed at Brookhaven National Laboratory (BNL) for the to control the AGS Booster beam. That beam control system, now under development, relies on VME modules and daughter boards based on Digital Signal Processors (DSPs) and Field Programmable Gate Arrays (FPGAs). The DSP provides high throughput processing capabilities and ease of connection with the software layer immediately above, while the daughter boards implement master clock, digital receiver and modulator capabilities. The resulting system is very flexible because is configurable via software and offers multi-processing capabilities and high bandwidth data paths, features that make it very attractive for a beam control implementation. For application t...

  3. Fuzzy logic scheme for tip-sample distance control for a low cost near field optical microscope

    Directory of Open Access Journals (Sweden)

    J.A. Márquez

    2013-12-01

    Full Text Available The control of the distance between the surface and the tip-sample of a Scanning Near Field Optical Microscope (SNOM is essential for a reliable surface mapping. The control algorithm should be able to maintain the system in a constant distance between the tip and the surface. In this system, nanometric adjustments should be made in order to sense topographies at the same scale with an appropriate resolution. These kinds of devices varies its properties through short periods of time, and it is required a control algorithm capable of handle these changes. In this work a fuzzy logic control scheme is proposed in order to manage the changes the device might have through the time, and to counter the effects of the non-linearity as well. Two inputs are used to program the rules inside the fuzzy logic controller, the difference between the reference signal and the sample signal (error, and the speed in which it decreases or increases. A lock-in amplifier is used as data acquisition hardware to sample the high frequency signals used to produce the tuning fork oscillations. Once these variables are read the control algorithm calculate a voltage output to move the piezoelectric device, approaching or removing the tip-probe from the sample analyzed.

  4. A pragmatic randomised controlled trial of the Welsh National Exercise Referral Scheme: protocol for trial and integrated economic and process evaluation

    Directory of Open Access Journals (Sweden)

    Hale Janine

    2010-06-01

    Full Text Available Abstract Background The benefits to health of a physically active lifestyle are well established and there is evidence that a sedentary lifestyle plays a significant role in the onset and progression of chronic disease. Despite a recognised need for effective public health interventions encouraging sedentary people with a medical condition to become more active, there are few rigorous evaluations of their effectiveness. Following NICE guidance, the Welsh national exercise referral scheme was implemented within the context of a pragmatic randomised controlled trial. Methods/Design The randomised controlled trial, with nested economic and process evaluations, recruited 2,104 inactive men and women aged 16+ with coronary heart disease (CHD risk factors and/or mild to moderate depression, anxiety or stress. Participants were recruited from 12 local health boards in Wales and referred directly by health professionals working in a range of health care settings. Consenting participants were randomised to either a 16 week tailored exercise programme run by qualified exercise professionals at community sports centres (intervention, or received an information booklet on physical activity (control. A range of validated measures assessing physical activity, mental health, psycho-social processes and health economics were administered at 6 and 12 months, with the primary 12 month outcome measure being 7 day Physical Activity Recall. The process evaluation explored factors determining the effectiveness or otherwise of the scheme, whilst the economic evaluation determined the relative cost-effectiveness of the scheme in terms of public spending. Discussion Evaluation of such a large scale national public health intervention presents methodological challenges in terms of trial design and implementation. This study was facilitated by early collaboration with social research and policy colleagues to develop a rigorous design which included an innovative approach

  5. Modelling of an irrigation scheme with sediment-laden water for improved water management: a case study of Sunsari Morang Irrigation Scheme, Nepal

    NARCIS (Netherlands)

    Paudel, K.; Schultz, E.; Depeweg, H.

    2013-01-01

    Irrigation schemes with sediment-laden water are generally performing significantly below expectation and potential. Managing such irrigation schemes is challenging as in most cases the management aspects of sediment transport were not included in the design process and in some cases the proposed

  6. Identity Establishment and Capability Based Access Control (IECAC) Scheme for Internet of Things

    DEFF Research Database (Denmark)

    Mahalle, Parikshit N.; Anggorojati, Bayu; Prasad, Neeli R.

    2012-01-01

    Internet of Things (IoT) become discretionary part of everyday life and could befall a threat if security is not considered before deployment. Authentication and access control in IoT is equally important to establish secure communication between devices. To protect IoT from man in middle, replay...... and denial of service attacks, the concept of capability for access control is introduced. This paper presents Identity establishment and capability based access control (IECAC) protocol using ECC (Elliptical Curve Cryptography) for IoT along with protocol evaluation, which protect against the aforementioned...

  7. Coordinated Voltage Control Scheme for SEIG-Based Wind Park Utilizing Substation STATCOM and ULTC Transformer

    DEFF Research Database (Denmark)

    S. El Moursi, Mohamed; Bak-Jensen, Birgitte; Abdel-Rahman, Mansour Hassan

    2011-01-01

    and optimal tracking secondary voltage control for wind parks based on self-excited induction generators which comprise STATCOM and under-load tap changer (ULTC) substation transformers. The voltage controllers for the STATCOM and ULTC transformer are coordinated and ensure the voltage support. In steady...... of the short circuit ratio of the interconnection and the inherent communication delay between the wind park and the remote bus on the performance of the controllers and the maximum critical clearing time of fault are considered. Simulation results are presented to demonstrate the performance...

  8. Compensation methods applied in current control schemes for large AC drive systems

    DEFF Research Database (Denmark)

    Rus, D. C.; Preda, N. S.; Teodorescu, Remus

    2012-01-01

    The paper deals with modified PI current control structures for large AC drive systems which use surface mounted permanent magnet synchronous machines or squirrel-cage induction motors supplied with voltage source inverters. In order to reduce the power losses caused by high frequency switching...... of the semiconductor devices, various compensation methods are used and a modified structure for a PI current controller is proposed, to reduce the switching frequency of the inverter for the same operating frequency of the drive. Simulation, experimental development and test results are presented in order...... to demonstrate the capabilities of the control procedure....

  9. An Islanding Microgrid Power Sharing Approach Using Enhanced Virtual Impedance Control Scheme

    DEFF Research Database (Denmark)

    He, Jinwei; Li, Yun Wei; Guerrero, Josep M.

    2013-01-01

    feed-forward terms, respectively. With this modification, the impacts of mismatched physical feeder impedances are compensated. Thus, better reactive and harmonic power sharing can be realized. Additionally, this paper also demonstrates that PCC harmonic voltages can be mitigated by reducing...... the magnitude of DG unit equivalent harmonic impedance. Finally, in order to alleviate the computing load at DG unit local controller, this paper further exploits the band-pass capability of conventionally resonant controllers. With the implementation of proposed resonant controller, accurate power sharing......In order to address the load sharing problem in islanding microgrids, this paper proposes an enhanced distributed generation (DG) unit virtual impedance control approach. The proposed method can realize accurate regulation of DG unit equivalent impedance at both fundamental and selected harmonic...

  10. A direct torque control scheme for permanent magnet synchronous motors based on space vector modulation

    Science.gov (United States)

    Su, Xiao-hui; Xu, Shu-Ping

    2013-03-01

    In order to solve the problem of direct torque control (DTC) for permanent magnet synchronous motor (PMSM) related to the flux and the torque ripple and the uncertainty of switching frequency, A novel direct torque control system based on space vector modulation(SVM-DTC) for permanent magnet synchronous motor was proposed. In this method flux and torque are controlled through stator voltage components in stator flux linkage coordinate axes and space vector modulation is used to control inverters. Therefore, the errors of torque and flux linkage could be compensated accurately. The whole system has only one easily adjustable PI adjuster and needs no high for hardware and easy for realize. The simulation results verify the feasibility of this method, reduction of the flux and the torque ripple, and the good performance of DTC.

  11. The Onset of a Novel Environmental Offset: A case study for diverse pollutant scheme in Australia.

    Science.gov (United States)

    Sengupta, A.; Arora, M.; Delbridge, N.; Pettigrove, V.; Feldman, D.

    2014-12-01

    enrichment downstream could occur. This study demonstrates an innovative case for evaluating net environmental benefits, and might hold important lessons for the design of offset schemes in comparable environments elsewhere.

  12. Derivation and Analysis of a Low-Cost, High-performance Analogue BPCM Control Scheme for Class-D Audio Power Amplifiers

    DEFF Research Database (Denmark)

    Høyerby, Mikkel Christian Wendelboe; Andersen, Michael A. E.

    2005-01-01

    This paper presents a low-cost analogue control scheme for class-D audio power amplifiers. The scheme is based around bandpass current-mode (BPCM) control, and provides ample stability margins and low distortion over a wide range of operating conditions. Implementation is very simple and does...... not require the use of operational amplifiers. Small-signal behavior of the controller is accurately predicted, and design is carried out using standard transfer function based linear control methodology. Effectiveness of the approach is demonstrated via a 60W/8Ω single-ended switching amplifier with THD...

  13. Clinical radiobiology of glioblastoma multiforme. Estimation of tumor control probability from various radiotherapy fractionation schemes

    Energy Technology Data Exchange (ETDEWEB)

    Pedicini, Piernicola [I.R.C.C.S.-Regional-Cancer-Hospital-C.R.O.B, Unit of Nuclear Medicine, Department of Radiation and Metabolic Therapies, Rionero-in-Vulture (Italy); Department of Radiation and Metabolic Therapies, I.R.C.C.S.-Regional-Cancer-Hospital-C.R.O.B, Unit of Radiotherapy, Rionero-in-Vulture (Italy); Fiorentino, Alba [Sacro Cuore - Don Calabria Hospital, Radiation Oncology Department, Negrar, Verona (Italy); Simeon, Vittorio [I.R.C.C.S.-Regional-Cancer-Hospital-C.R.O.B, Laboratory of Preclinical and Translational Research, Rionero-in-Vulture (Italy); Tini, Paolo; Pirtoli, Luigi [University of Siena and Tuscany Tumor Institute, Unit of Radiation Oncology, Department of Medicine Surgery and Neurological Sciences, Siena (Italy); Chiumento, Costanza [Department of Radiation and Metabolic Therapies, I.R.C.C.S.-Regional-Cancer-Hospital-C.R.O.B, Unit of Radiotherapy, Rionero-in-Vulture (Italy); Salvatore, Marco [I.R.C.C.S. SDN Foundation, Unit of Nuclear Medicine, Napoli (Italy); Storto, Giovanni [I.R.C.C.S.-Regional-Cancer-Hospital-C.R.O.B, Unit of Nuclear Medicine, Department of Radiation and Metabolic Therapies, Rionero-in-Vulture (Italy)

    2014-10-15

    The aim of this study was to estimate a radiobiological set of parameters from the available clinical data on glioblastoma (GB). A number of clinical trial outcomes from patients affected by GB and treated with surgery and adjuvant radiochemotherapy were analyzed to estimate a set of radiobiological parameters for a tumor control probability (TCP) model. The analytical/graphical method employed to fit the clinical data allowed us to estimate the intrinsic tumor radiosensitivity (α), repair capability (b), and repopulation doubling time (T{sub d}) in a first phase, and subsequently the number of clonogens (N) and kick-off time for accelerated proliferation (T{sub k}). The results were used to formulate a hypothesis for a scheduleexpected to significantly improve local control. The 95 % confidence intervals (CI{sub 95} {sub %}) of all parameters are also discussed. The pooled analysis employed to estimate the parameters summarizes the data of 559 patients, while the studies selected to verify the results summarize data of 104 patients. The best estimates and the CI{sub 95} {sub %} are α = 0.12 Gy{sup -1} (0.10-0.14), b = 0.015 Gy{sup -2} (0.013-0.020), α/b = 8 Gy (5.0-10.8), T{sub d} = 15.4 days (13.2-19.5), N = 1 . 10{sup 4} (1.2 . 10{sup 3} - 1 . 10{sup 5}), and T{sub k} = 37 days (29-46). The dose required to offset the repopulation occurring after 1 day (D{sub prolif}) and starting after T{sub k} was estimated as 0.30 Gy/day (0.22-0.39). The analysis confirms a high value for the α/b ratio. Moreover, a high intrinsic radiosensitivity together with a long kick-off time for accelerated repopulation and moderate repopulation kinetics were found. The results indicate a substantial independence of the duration of the overall treatment and an improvement in the treatment effectiveness by increasing the total dose without increasing the dose fraction. (orig.) [German] Schaetzung eines strahlenbiologischen Parametersatzes auf der Grundlage klinischer Daten bei

  14. Novel Observer Scheme of Fuzzy-MRAS Sensorless Speed Control of Induction Motor Drive

    Science.gov (United States)

    Chekroun, S.; Zerikat, M.; Mechernene, A.; Benharir, N.

    2017-01-01

    This paper presents a novel approach Fuzzy-MRAS conception for robust accurate tracking of induction motor drive operating in a high-performance drives environment. Of the different methods for sensorless control of induction motor drive the model reference adaptive system (MRAS) finds lot of attention due to its good performance. The analysis of the sensorless vector control system using MRAS is presented and the resistance parameters variations and speed observer using new Fuzzy Self-Tuning adaptive IP Controller is proposed. In fact, fuzzy logic is reminiscent of human thinking processes and natural language enabling decisions to be made based on vague information. The present approach helps to achieve a good dynamic response, disturbance rejection and low to plant parameter variations of the induction motor. In order to verify the performances of the proposed observer and control algorithms and to test behaviour of the controlled system, numerical simulation is achieved. Simulation results are presented and discussed to shown the validity and the performance of the proposed observer.

  15. Stability Properties and Cross Coupling Performance of the Control Allocation Scheme CAPIO

    Science.gov (United States)

    Yildiz, Yildiray; Kolmanovsky, Ilya V.

    2010-01-01

    This paper presents a stability analysis and an application of a recently developed Control Allocator for recovery from Pilot Induced Oscillations (CAPIO). When actuators are rate-saturated due to either aggressive pilot commands, high gain ight control systems or some anomaly in the system, the effective delay in the control loop may increase. This effective delay increase manifests itself as a phase shift between the commanded and actual system signals and can instigate Pilot induced Oscillations (PIO). CAPIO reduces the e ective time delay by minimizing the phase shift between the commanded and the actual attitude accelerations. We present a stability analysis of CAPIO for a scalar system. In addition, we present simulation results for aircraft with cross-coupling which demonstrates the potential of CAPIO serving as an effective PIO handler in adverse conditions.

  16. Smart Control Scheme Planned for an Evaporator Based on Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Reza Yazdanpanah

    2017-09-01

    Full Text Available In this paper, Particle Swarm Optimization (PSO is utilized to optimize the coefficients of a level controller and 2×2 decentralized PI controller and a lead compensator for a forced circulation evaporator. The mathematical model of the evaporator system is approximated at the operating point for PSO algorithm to adjust the evaporator control system parameters for minimizing the summation of desired characteristics, such as overshoot, rise time, settling time, steady state error and the performance index such as integral of time-weighted absolute error (ITAE. The forced circulation evaporator is modelled in SIMULINK and PSO algorithm is implemented in MATLAB. Compared with Genetic Algorithm (GA, the simulation results verify the superiority of PSO over GA.

  17. An Evaluation of Fault Tolerant Wind Turbine Control Schemes applied to a Benchmark Model

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob

    2014-01-01

    an international competition on wind turbine fault tolerant control has been proposed. In this article the top three solutions from this wind fault tolerant control competition are introduced and evaluated. The evaluation presented in this paper shows that the winner of the competition performs very well...... on this benchmark and is especially good accommodating sensors faults. The two other evaluated solutions do also well accommodating sensors faults, but have some issues which should be worked on, before they can be considered as a full solution to the benchmark problem....

  18. Performance Assessment of the VSC Using Two Model Predictive Control Schemes

    DEFF Research Database (Denmark)

    Al hasheem, Mohamed; Abdelhakim, Ahmed; Dragicevic, Tomislav

    2018-01-01

    and 2L-VSC efficiency. The results also demonstrate the performance of the system using carrier based pulse width modulation (CB-PWM). These findings have been validated for both linear and non-linear loads through experimental verification on 4 kW 2L-VSC prototype. It can be concluded that a comparable......Finite control set model predictive control (FCS-MPC) methods in different power electronics application are gaining high attention due to their simplicity and fast dynamics. This paper introduces an experimental assessment of the two-level three-phase voltage source converter (2L-VSC) using two...

  19. An Islanding Microgrid Power Sharing Approach Using Enhanced Virtual Impedance Control Scheme

    DEFF Research Database (Denmark)

    He, Jinwei; Li, Yun Wei; Guerrero, Josep M.

    2013-01-01

    In order to address the load sharing problem in islanding microgrids, this paper proposes an enhanced distributed generation (DG) unit virtual impedance control approach. The proposed method can realize accurate regulation of DG unit equivalent impedance at both fundamental and selected harmonic ...... and PCC harmonic voltage compensation are achieved without using any fundamental and harmonic components extractions. Experimental results from a scaled single-phase microgrid prototype are provided to validate the feasibility of the proposed virtual impedance control approach.......In order to address the load sharing problem in islanding microgrids, this paper proposes an enhanced distributed generation (DG) unit virtual impedance control approach. The proposed method can realize accurate regulation of DG unit equivalent impedance at both fundamental and selected harmonic...... frequencies. In contrast to conventional virtual impedance control methods, where only a line current feed-forward term is added to the DG voltage reference, the proposed virtual impedance at fundamental and harmonic frequencies is regulated using DG line current and point of common coupling (PCC) voltage...

  20. Robust and fast schemes in broadband active noise and vibration control

    NARCIS (Netherlands)

    Fraanje, P.R.

    2004-01-01

    This thesis presents robust and fast active control algorithms for the suppression of broadband noise and vibration disturbances. Noise disturbances, e.g., generated by engines in airplanes and cars or by air ow, can be reduced by means of passive or active methods.

  1. Application of an H-infinity based FDI and control scheme for the three tank system

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, H.

    2000-01-01

    The three tank benchmark system is considered in this paper in connection with combined feedback control and fault detection and identification (FDI). The combined design problem is formulated as an H-infinity design problem by using a standard system setup...

  2. Automated adaptive sliding mode control scheme for a class of real ...

    Indian Academy of Sciences (India)

    Complicated systems; efficient automated adaptive sliding mode controlscheme; non-identical hyper-chaotic master/slave systems; synchronization error; numerical ... Department of Electrical Engineering, Birjand Branch, Islamic Azad University (IAU), Birjand, Iran; Department of Control Engineering, Faculty of Electrical ...

  3. Joint Optimized CPU and Networking Control Scheme for Improved Energy Efficiency in Video Streaming on Mobile Devices

    Directory of Open Access Journals (Sweden)

    Sung-Woong Jo

    2017-01-01

    Full Text Available Video streaming service is one of the most popular applications for mobile users. However, mobile video streaming services consume a lot of energy, resulting in a reduced battery life. This is a critical problem that results in a degraded user’s quality of experience (QoE. Therefore, in this paper, a joint optimization scheme that controls both the central processing unit (CPU and wireless networking of the video streaming process for improved energy efficiency on mobile devices is proposed. For this purpose, the energy consumption of the network interface and CPU is analyzed, and based on the energy consumption profile a joint optimization problem is formulated to maximize the energy efficiency of the mobile device. The proposed algorithm adaptively adjusts the number of chunks to be downloaded and decoded in each packet. Simulation results show that the proposed algorithm can effectively improve the energy efficiency when compared with the existing algorithms.

  4. A hybrid cascade control scheme for the VFA and COD regulation in two-stage anaerobic digestion processes.

    Science.gov (United States)

    Méndez-Acosta, H O; Campos-Rodríguez, A; González-Álvarez, V; García-Sandoval, J P; Snell-Castro, R; Latrille, E

    2016-10-01

    A hybrid (continuous-discrete) cascade control is proposed to regulate both, volatile fatty acids (VFA) and chemical oxygen demand (COD) concentrations in two-stage (acidogenic-methanogenic) anaerobic digestion (TSAD) processes. The outer loop is a discrete controller that regulates the COD concentration of the methanogenic bioreactor by using a daily off-line measurement and that modifies the set-point tracked by inner loop, which manipulates the dilution rate to regulate the VFA concentration of the acidogenic bioreactor, estimated by continuous on-line conductivity measurements, avoiding acidification. The experimental validation was conducted in a TSAD process for the treatment of tequila vinasses during 110days. Results showed that the proposed cascade control scheme was able to achieve the VFA and COD regulation by using conventional measurements under different set-point values in spite of adverse common scenarios in full-scale anaerobic digestion processes. Microbial composition analysis showed that the controller also favors the abundance and diversity toward methane production. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Effective Pneumatic Scheme and Control Strategy of a Climbing Robot for Class Wall Cleaning on High-rise Buildings

    Directory of Open Access Journals (Sweden)

    Houxiang Zhang

    2006-06-01

    Full Text Available A new kind of pneumatic climbing robot is presented to meet the requirements of glass-wall cleaning for high-rise buildings, which is totally actuated by pneumatic cylinders and attached to the glass wall with vacuum suckers. Using the pneumatic actuators the climbing robot can be made lightweight and dexterous. At the same time the movement driven by pneumatic actuators has the characteristic of passive compliance. In order to solve the problems of high speed movement for the Y cylinder and precise position control of the X cylinder, the applied pneumatic schemes of X and Y cylinders are employed to drive the high-speed on-off solenoid valves and an ordinary valve to adjust the air-flow and pressure to the cylinders. Furthermore a method of segment and variable bang-bang controller is proposed to implement the accurate control of the position servo system for the X cylinder during the sideways movement. Testing results show that the novel approach can effectively improve the control quality. This cleaning robot can meet the requirements of realization.

  6. Effective Pneumatic Scheme and Control Strategy of a Climbing Robot for Class Wall Cleaning on High-rise Buildings

    Directory of Open Access Journals (Sweden)

    Guanghua Zong

    2008-11-01

    Full Text Available A new kind of pneumatic climbing robot is presented to meet the requirements of glass-wall cleaning for high-rise buildings, which is totally actuated by pneumatic cylinders and attached to the glass wall with vacuum suckers. Using the pneumatic actuators the climbing robot can be made lightweight and dexterous. At the same time the movement driven by pneumatic actuators has the characteristic of passive compliance. In order to solve the problems of high speed movement for the Y cylinder and precise position control of the X cylinder, the applied pneumatic schemes of X and Y cylinders are employed to drive the high-speed on-off solenoid valves and an ordinary valve to adjust the air-flow and pressure to the cylinders. Furthermore a method of segment and variable bang-bang controller is proposed to implement the accurate control of the position servo system for the X cylinder during the sideways movement. Testing results show that the novel approach can effectively improve the control quality. This cleaning robot can meet the requirements of realization.

  7. Hybrid control scheme for distributed energy resource management in a market context

    DEFF Research Database (Denmark)

    Han, Xue; Bindner, Henrik W.; Mehmedalic, Jasmin

    2015-01-01

    flexibility to meet regular demand from the distribution system operator (DSO). By considering both their physical constraints and the economical system operation, this paper proposes a realtime hybrid management system for DER units in a market environment, which considers both the request from the DSO...... and their local conditions. Voltage regulation service is formulated and implemented in the control frame. The performance is evaluated through simulation on an existing Danish MV and LV distribution grid and is compared with a local control method and the passive operation condition.......In modernizing the electricity grid, distributed energy resources (DERs) can play an important role in accommodating intermittent energy sources, assisting system operation and the transition to a smart grid. Proper aggregation and coordination of the available DER units is required to provide...

  8. Improved FRT Control Scheme for DFIG Wind Turbine Connected to a Weak Grid

    OpenAIRE

    Abulanwar, Elsayed; Chen, Zhe; Iov, Florin

    2013-01-01

    This paper presents an improved coordinated fault ridethrough (FRT) control strategy for a doubly fed induction generator (DFIG) based wind turbine, (WT), in a weak grid. A technique for grid synchronization against voltage excursions, i.e., a Dual Second Order Generalized Integrator – Frequency Locked Loop (DSOGIFLL) is utilized to extract a robust grid voltage synchronizationsignal irrespective of the mains condition to enhance the overall system performance. Besides, a decoupled double syn...

  9. An Adaptive Fuzzy Control Scheme for Dyebath pH in Exhaust Dyeing

    African Journals Online (AJOL)

    Nafiisah

    The corresponding pH and ISE responses are shown in Figures 9 and 10, respectively. In this case the dyebath pH is characterized by high overshoots at the start of the process, and a steady-state error 0.7 pH at 2400 s, with a corresponding ISE exceeding 1400 pH2s. Table 2 Process and Controller parameters. Parameter.

  10. Numerical study of read scheme in one-selector one-resistor crossbar array

    Science.gov (United States)

    Kim, Sungho; Kim, Hee-Dong; Choi, Sung-Jin

    2015-12-01

    A comprehensive numerical circuit analysis of read schemes of a one selector-one resistance change memory (1S1R) crossbar array is carried out. Three schemes-the ground, V/2, and V/3 schemes-are compared with each other in terms of sensing margin and power consumption. Without the aid of a complex analytical approach or SPICE-based simulation, a simple numerical iteration method is developed to simulate entire current flows and node voltages within a crossbar array. Understanding such phenomena is essential in successfully evaluating the electrical specifications of selectors for suppressing intrinsic drawbacks of crossbar arrays, such as sneaky current paths and series line resistance problems. This method provides a quantitative tool for the accurate analysis of crossbar arrays and provides guidelines for developing an optimal read scheme, array configuration, and selector device specifications.

  11. Continuous quality control of the blood sampling procedure using a structured observation scheme

    DEFF Research Database (Denmark)

    Seemann, Tine Lindberg; Nybo, Mads

    2016-01-01

    blood drawings by 39 phlebotomists were observed in the pilot study, while 84 blood drawings by 34 phlebotomists were observed in the follow-up study. In the pilot study, the three major error items were hand hygiene (42% error), mixing of samples (22%), and order of draw (21%). Minor significant...

  12. An online re-linearization scheme suited for Model Predictive and Linear Quadratic Control

    DEFF Research Database (Denmark)

    Henriksen, Lars Christian; Poulsen, Niels Kjølstad

    This technical note documents the equations for primal-dual interior-point quadratic programming problem solver used for MPC. The algorithm exploits the special structure of the MPC problem and is able to reduce the computational burden such that the computational burden scales with prediction...... horizon length in a linear way rather than cubic, which would be the case if the structure was not exploited. It is also shown how models used for design of model-based controllers, e.g. linear quadratic and model predictive, can be linearized both at equilibrium and non-equilibrium points, making...

  13. Colour schemes

    DEFF Research Database (Denmark)

    van Leeuwen, Theo

    2013-01-01

    This chapter presents a framework for analysing colour schemes based on a parametric approach that includes not only hue, value and saturation, but also purity, transparency, luminosity, luminescence, lustre, modulation and differentiation.......This chapter presents a framework for analysing colour schemes based on a parametric approach that includes not only hue, value and saturation, but also purity, transparency, luminosity, luminescence, lustre, modulation and differentiation....

  14. Design of a Distributed Personal Information Access Control Scheme for Secure Integrated Payment in NFC

    Directory of Open Access Journals (Sweden)

    Jungho Kang

    2015-06-01

    Full Text Available At the center of core technologies for a future cyber world, such as Internet of Things (IoT or big data, is a context-rich system that offers services by using situational information. The field where context-rich systems were first introduced is near-field communication (NFC-based electronic payments. Near-field Communication (NFC integrated payment services collect the payment information of the credit card and the location information to generate patterns in the user’s consumption or movement through big data technology. Based on such pattern information, tailored services, such as advertisement, are offered to users. However, there is difficulty in controlling access to personal information, as there is a collaborative relationship focused on the trusted service manager (TSM that is close knit to shared personal information. Moreover, in the case of Hadoop, among the many big data analytical technologies, it offers access control functions, but not a way to authorize the processing of personal information, making it impossible to grant authority between service providers to process information. As such, this paper proposes a key generation and distribution method, as well as a secure communication protocol. The analysis has shown that the efficiency was greater for security and performance compared to relation works.

  15. A Hybrid Scheme Motion Controller by Sliding Mode and Two-Degree-of-Freedom Controls to Minimize the Chattering

    Directory of Open Access Journals (Sweden)

    Chiu-Keng Lai

    2014-01-01

    Full Text Available Sliding mode control (SMC is rapped for the chattering due to high gain control. However, high gain control causes the system robust. For developing a system with robustness of SMC, a servo motor motion controller combining the two-degree-of-freedom (2DOF system and SMC is proposed. The discussed motion type is point-to-point control with the constraint of trapezoid velocity profile. SMC is designed to guide the motor motion to follow a predefined trail, and the inner 2DOF system is used to compensate the deterioration due to the adoption of load observer. The proposed hybrid system is realized on a PC-based motion controller, and the validness is verified by simulation and experimental results.

  16. Master-slave control scheme in electric vehicle smart charging infrastructure.

    Science.gov (United States)

    Chung, Ching-Yen; Chynoweth, Joshua; Chu, Chi-Cheng; Gadh, Rajit

    2014-01-01

    WINSmartEV is a software based plug-in electric vehicle (PEV) monitoring, control, and management system. It not only incorporates intelligence at every level so that charge scheduling can avoid grid bottlenecks, but it also multiplies the number of PEVs that can be plugged into a single circuit. This paper proposes, designs, and executes many upgrades to WINSmartEV. These upgrades include new hardware that makes the level 1 and level 2 chargers faster, more robust, and more scalable. It includes algorithms that provide a more optimal charge scheduling for the level 2 (EVSE) and an enhanced vehicle monitoring/identification module (VMM) system that can automatically identify PEVs and authorize charging.

  17. a Cumulus Parameterization Study with Special Attention to the Arakawa-Schubert Scheme

    Science.gov (United States)

    Kao, Chih-Yue Jim

    Arakawa and Schubert (1974) developed a cumulus parameterization scheme in a framework that conceptually divides the mutual interaction of the cumulus convection and large-scale disturbance into the categories of large -scale budget requirements and the quasi-equilibrium assumption of cloud work function. We have applied the A-S scheme through a semi-prognostic approach to two different data sets: one is for an intense tropical cloud band event; the other is for tropical composite easterly wave disturbances. Both were observed in GATE. The cloud heating and drying effects predicted by the Arakawa-Schubert scheme are found to agree rather well with the observations. However, it is also found that the Arakawa-Schubert scheme underestimates both condensation and evaporation rates substantially when compared with the cumulus ensemble model results (Soong and Tao, 1980; Tao, 1983). An inclusion of the downdraft effects, as formulated by Johnson (1976), appears to alleviate this deficiency. In order to examine how the Arakawa-Schubert scheme works in a fully prognostic problem, a simulation of the evolution and structure of the tropical cloud band, mentioned above, under the influence of an imposed large-scale low -level forcing has been made, using a two-dimensional hydrostatic model with the inclusion of the Arakawa-Schubert scheme. Basically, the model result indicates that the meso-scale convective system is driven by the excess of the convective heating derived from the Arakawa-Schubert scheme over the adiabatic cooling due to the imposed large-scale lifting and induced meso-scale upward motion. However, as the convective system develops, the adiabatic warming due to the subsidence outside the cloud cluster gradually accumulates into a secondary temperature anomaly which subsequently reduces the original temperature contrast and inhibits the further development of the convective system. A 24 hour integration shows that the model is capable of simulating many

  18. Simulation studies of a novel electromagnetic actuation scheme for focusing magnetic micro/nano-carriers into a deep target region

    Directory of Open Access Journals (Sweden)

    Tuan-Anh Le

    2017-05-01

    Full Text Available The ability to focus spherical particles (SPPs to a deep tumor region remains one of the major challenges in magnetic drug targeting (MDT. A number of studies have attempted to overcome this problem using fast magnetic pulses and ferromagnetic rods. However, focusing of the SPPs in the deep body organs remains unsolved using existing schemes. In this paper, we propose a novel electro-magnetic actuation scheme for pushing and focusing SPPs. The simulation results demonstrate that the newly proposed actuation scheme can focus SPPs to a target surface region, inside of a block filled with an environment that has the characteristics of blood. We then investigated the effects of the proposed focusing scheme in realistic blood vessels with a maximum length of about 10–12 cm. The results show that SPPs of 500 nm can be concentrated onto a target tumor region with up to 97.9% efficiency. The proposed electromagnetic actuation scheme can maximize the efficiency of MDT, while minimizing the side effects of drugs in other tissues.

  19. Simulation studies of a novel electromagnetic actuation scheme for focusing magnetic micro/nano-carriers into a deep target region

    Science.gov (United States)

    Le, Tuan-Anh; Zhang, Xingming; Hoshiar, Ali Kafash; Kim, Myeong Ok; Yoon, Jungwon

    2017-05-01

    The ability to focus spherical particles (SPPs) to a deep tumor region remains one of the major challenges in magnetic drug targeting (MDT). A number of studies have attempted to overcome this problem using fast magnetic pulses and ferromagnetic rods. However, focusing of the SPPs in the deep body organs remains unsolved using existing schemes. In this paper, we propose a novel electro-magnetic actuation scheme for pushing and focusing SPPs. The simulation results demonstrate that the newly proposed actuation scheme can focus SPPs to a target surface region, inside of a block filled with an environment that has the characteristics of blood. We then investigated the effects of the proposed focusing scheme in realistic blood vessels with a maximum length of about 10-12 cm. The results show that SPPs of 500 nm can be concentrated onto a target tumor region with up to 97.9% efficiency. The proposed electromagnetic actuation scheme can maximize the efficiency of MDT, while minimizing the side effects of drugs in other tissues.

  20. Tunneling dynamics in open ultracold bosonic systems. Numerically exact dynamics - Analytical models - Control schemes

    Energy Technology Data Exchange (ETDEWEB)

    Lode, Axel U.J.

    2013-06-03

    This thesis explores the quantum many-body tunneling dynamics of open ultracold bosonic systems with the recently developed multiconfigurational time-dependent Hartree for bosons (MCTDHB) method. The capabilities of MCTDHB to provide solutions to the full time-dependent many-body problem are assessed in a benchmark using the analytically solvable harmonic interaction Hamiltonian and a generalization of it with time-dependent both one- and two-body potentials. In a comparison with numerically exact MCTDHB results, it is shown that e.g. lattice methods fail qualitatively to describe the tunneling dynamics. A model assembling the many-body physics of the process from basic simultaneously happening single-particle processes is derived and verified with a numerically exact MCTDHB description. The generality of the model is demonstrated even for strong interactions and large particle numbers. The ejection of the bosons from the source occurs with characteristic velocities. These velocities are defined by the chemical potentials of systems with different particle numbers which are converted to kinetic energy. The tunneling process is accompanied by fragmentation: the ejected bosons lose their coherence with the source and among each other. It is shown that the various aspects of the tunneling dynamics' can be controlled well with the interaction and the potential threshold.

  1. Study of Back Biasing Schemes for ULV Logic from the Gate Level to the IP Level

    Directory of Open Access Journals (Sweden)

    Guerric de Streel

    2014-07-01

    Full Text Available Minimum energy per operation is typically achieved in the subthreshold region where low speed and low robustness are two challenging problems. This paper studies the impact of back biasing (BB schemes on these features for 28 nm FDSOI technology at three levels of abstraction: gate, library and IP. We show that forward BB (FBB can help cover a wider design space in terms of the optimal frequency of operation while keeping minimum energy. Asymmetric BB between NMOS and PMOS can mitigate the effect of systematic mismatch on the minimum energy point (MEP and robustness. With optimal asymmetric BB, we achieve either a MEP reduction up to 18% or a 36× speedup at the MEP. At the IP level, we confirm the MEP configurability with BB with synthesis results of microcontrollers at 0.35 V.We show that the use of a mix of overdrive FBB voltages further improves the energy efficiency. Compared to bulk 65 nm CMOS, we were able 28 nm FDSOI to reduce the energy per cycle by 64% or to increase the frequency of operation by 7×, while maintaining energy per operation below 3 µW/MHz over a wide frequency range.

  2. Biostratigraphical study around the Jurassic/Cretaceous boundary in Central Tunisia zonal schemes and correlation

    Science.gov (United States)

    Maalaoui, Kamel; Zargouni, Fouad

    2017-01-01

    The fossil data from Central Tunisia has led to the recognition of ten calpionellid and ammonite zones and subzones in the Upper Tithonian-Middle Berriasian interval. The results of this revision are congruent with local interval zones and they were tested with the Mediterranean zonal schemes. Six subzones of calpionellids constitute the basis of our investigations in this study. We recognized the A2+A3, B1, B2, B3, C1 and C2 Subzones. These subzones are calibrated with the ammonite biozones: Berriasella jacobi and Subthurmannia occitanica Zones. Integration of the biostratigraphy of ammonites and calpionellids has allowed us to define the J/K boundary interval and the Middle/Upper Berriasian boundary. Biostratigraphic data provided by the two sections in Central Tunisia allowed the revision of the biostratigraphic attribution of Sidi Kralif Formation. These faunas suggest a late Tithonian to mid Berriasian age for the Jebel Rheouis section, and early Berriasian to mid Berriasian age for Jebel Meloussi section; correlating with their equivalents in other regions of the Tethyan Realm.

  3. A Study on the Security Levels of Spread-Spectrum Embedding Schemes in the WOA Framework.

    Science.gov (United States)

    Wang, Yuan-Gen; Zhu, Guopu; Kwong, Sam; Shi, Yun-Qing

    2017-08-23

    Security analysis is a very important issue for digital watermarking. Several years ago, according to Kerckhoffs' principle, the famous four security levels, namely insecurity, key security, subspace security, and stego-security, were defined for spread-spectrum (SS) embedding schemes in the framework of watermarked-only attack. However, up to now there has been little application of the definition of these security levels to the theoretical analysis of the security of SS embedding schemes, due to the difficulty of the theoretical analysis. In this paper, based on the security definition, we present a theoretical analysis to evaluate the security levels of five typical SS embedding schemes, which are the classical SS, the improved SS (ISS), the circular extension of ISS, the nonrobust and robust natural watermarking, respectively. The theoretical analysis of these typical SS schemes are successfully performed by taking advantage of the convolution of probability distributions to derive the probabilistic models of watermarked signals. Moreover, simulations are conducted to illustrate and validate our theoretical analysis. We believe that the theoretical and practical analysis presented in this paper can bridge the gap between the definition of the four security levels and its application to the theoretical analysis of SS embedding schemes.

  4. Attracting doctors to rural areas: A case study of the post-graduate seat reservation scheme in Andhra Pradesh

    Directory of Open Access Journals (Sweden)

    Zubin C Shroff

    2013-01-01

    Full Text Available Background: Attracting doctors to rural posts is an ongoing challenge for health departments across different states in India. One strategy adopted by several states to make rural service attractive for medical graduates is to reserve post-graduate (PG seats in medical colleges for doctors serving in the public sector. Objective: This study examines the PG reservation scheme in Andhra Pradesh to understand its role in improving rural recruitment of doctors and specialists, the challenges faced by the scheme and how it can be strengthened. Materials and Methods: Qualitative case study methodology was adopted in which a variety of stakeholders such as government officials, health systems managers and serving Medical Officers were interviewed. This was supplemented with quantitative data on the scheme obtained from the Health, Medical and Family Welfare Department in Andhra Pradesh. Results: The PG reservation scheme appears to have been one of the factors responsible in attracting doctors to the public sector and to rural posts, with a reduction in vacancies at both the Primary Health Centre and Community Health Centre levels. Expectedly, in-service candidates have a better chance of getting a PG seat than general candidates. However, problems such as the mismatch of the demand and supply of certain types of specialist doctors, poor academic performance of in-service candidates as well as quality of services and enforcement of the post-PG bond need to be resolved. Conclusion: The PG reservation scheme is a powerful incentive to attract doctors to rural areas. However, better monitoring of service quality, strategically aligning PG training through the scheme with the demand for specialists as well as stricter enforcement of the financial bond are required to improve the scheme′s effectiveness.

  5. Studying and comparing spectrum efficiency and error probability in GMSK and DBPSK modulation schemes

    Directory of Open Access Journals (Sweden)

    Juan Mario Torres Nova

    2008-09-01

    Full Text Available Gaussian minimum shift keying (GMSK and differential binary phase shift keying (DBPSK are two digital modulation schemes which are -frequently used in radio communication systems; however, there is interdependence in the use of its benefits (spectral efficiency, low bit error rate, low inter symbol interference, etc. Optimising one parameter creates problems for another; for example, the GMSK scheme succeeds in reducing bandwidth when introducing a Gaussian filter into an MSK (minimum shift ke-ying modulator in exchange for increasing inter-symbol interference in the system. The DBPSK scheme leads to lower error pro-bability, occupying more bandwidth; it likewise facilitates synchronous data transmission due to the receiver’s bit delay when re-covering a signal.

  6. Studying and comparing spectrum efficiency and error probability in GMSK and DBPSK modulation schemes

    Directory of Open Access Journals (Sweden)

    Juan Mario Torres Nova

    2010-05-01

    Full Text Available Gaussian minimum shift keying (GMSK and differential binary phase shift keying (DBPSK are two digital modulation schemes which are -frequently used in radio communication systems; however, there is interdependence in the use of its benefits (spectral efficiency, low bit error rate, low inter symbol interference, etc. Optimising one parameter creates problems for another; for example, the GMSK scheme succeeds in reducing bandwidth when introducing a Gaussian filter into an MSK (minimum shift ke-ying modulator in exchange for increasing inter-symbol interference in the system. The DBPSK scheme leads to lower error pro-bability, occupying more bandwidth; it likewise facilitates synchronous data transmission due to the receiver’s bit delay when re-covering a signal.

  7. Government-Leading Student Loan Schemes A Comparative Study of Hong Kong and Mainland China

    Directory of Open Access Journals (Sweden)

    Antonia Jiewei Lu

    2014-02-01

    Full Text Available Having a careful examination of government-leading student loan schemes in China and Hong Kong, we can find a lot of differences and learn something from these two counterparts which are very typical country or area faced by challenges in financing higher education in the context of transition from elitism to mass higher education. This research attempts to make a comparison of government-leading student loan schemes between Hong Kong and China in the new century. Then emphasis is put on the principles or core values namely efficiency, equity and adequacy, and determining their implications presented in student loan schemes in these two counterparts. Finally, the paper arrives at some recommendations for improvements in them.

  8. Psychosocial mediators of change in physical activity in the Welsh national exercise referral scheme: secondary analysis of a randomised controlled trial.

    Science.gov (United States)

    Littlecott, Hannah J; Moore, Graham F; Moore, Laurence; Murphy, Simon

    2014-08-27

    While an increasing number of randomised controlled trials report impacts of exercise referral schemes (ERS) on physical activity, few have investigated the mechanisms through which increases in physical activity are produced. This study examines whether a National Exercise Referral Scheme (NERS) in Wales is associated with improvements in autonomous motivation, self-efficacy and social support, and whether change in physical activity is mediated by change in these psychosocial processes. A pragmatic randomised controlled trial of NERS across 12 LHBs in Wales. Questionnaires measured demographic data and physical activity at baseline. Participants (N = 2160) with depression, anxiety or CHD risk factors were referred by health professionals and randomly assigned to control or intervention. At six months psychological process measures were collected by questionnaire. At 12 months physical activity was assessed by 7 Day PAR telephone interview. Regressions tested intervention effects on psychosocial variables, physical activity before and after adjusting for mediators and socio demographic patterning. Significant intervention effects were found for autonomous motivation and social support for exercise at 6 months. No intervention effect was observed for self-efficacy. The data are consistent with a hypothesis of partial mediation of the intervention effect by autonomous motivation. Analysis of moderators showed significant improvements in relative autonomy in all subgroups. The greatest improvements in autonomous motivation were observed among patients who were least active at baseline. The present study offered key insights into psychosocial processes of change in an exercise referral scheme, with effects on physical activity mediated by autonomous motivation. Findings support the use of self-determination theory as a framework for ERS. Further research is required to explain socio-demographic patterning in responses to ERS, with changes in motivation occurring among

  9. A finite element scheme to study the nonlinear optical response of a finite grating without and with defect

    NARCIS (Netherlands)

    Suryanto, A.; van Groesen, Embrecht W.C.; Hammer, Manfred; Hoekstra, Hugo

    We present a simple numerical scheme based on the finite element method (FEM) using transparent-influx boundary conditions to study the nonlinear optical response of a finite one-dimensional grating with Kerr medium. Restricting first to the linear case, we improve the standard FEM to get a fourth

  10. Advocacy planning in resettlement schemes: A study of old and new ...

    African Journals Online (AJOL)

    The paper also contended that resettlement schemes without sound economic base and public participation is a mere human environmental distortion. And that advocacy planning is not anti-public planning but a complementary effort toward the attainment of rational comprehensive planning paradigm. Keywords: Advocacy ...

  11. A Comparative Study on Metadata Scheme of Chinese and American Open Data Platforms

    Directory of Open Access Journals (Sweden)

    Yang Sinan

    2018-01-01

    Full Text Available [Purpose/significance] Open government data is conducive to the rational development and utilization of data resources. It can encourage social innovation and promote economic development. Besides, in order to ensure effective utilization and social increment of open government data, high-quality metadata schemes is necessary. [Method/process] Firstly, this paper analyzed the related research of open government data at home and abroad. Then, it investigated the open metadata schemes of some Chinese main local governments’ data platforms, and made a comparison with the metadata standard of American open government data. [Result/conclusion] This paper reveals that there are some disadvantages about Chinese local government open data affect the use effect of open data, which including that different governments use different data metadata schemes, the description of data set is too simple for further utilization and usually presented in HTML Web page format with lower machine-readable. Therefore, our government should come up with a standardized metadata schemes by drawing on the international mature and effective metadata standard, to ensure the social needs of high quality and high value data.

  12. A Survey and Comparative Study of Broadcast Warning Message Dissemination Schemes for VANETs

    Directory of Open Access Journals (Sweden)

    Julio A. Sanguesa

    2016-01-01

    Full Text Available Vehicle-to-vehicle (V2V communications also known as vehicular ad hoc networks (VANETs allow vehicles to cooperate to increase driving efficiency and safety on the roads. In particular, they are forecasted as one of the key technologies to increase traffic safety by providing useful traffic services. In this scope, vehicle-to-vehicle dissemination of warning messages to alert nearby vehicles is one of the most significant and representative solutions. The main goal of the different dissemination strategies available is to reduce the message delivery latency of such information while ensuring the correct reception of warning messages in the vehicle’s neighborhood as soon as a dangerous situation occurs. Despite the fact that several dissemination schemes have been proposed so far, their evaluation has been done under different conditions, using different simulators, making it difficult to determine the optimal dissemination scheme for each particular scenario. In this paper, besides reviewing the most relevant broadcast dissemination schemes available in the recent literature, we also provide a fair comparative analysis by evaluating them under the same environmental conditions, focusing on the same metrics, and using the same simulation platform. Overall, we provide researchers with a clear guideline of the benefits and drawbacks associated with each scheme.

  13. On the Study of a Quadrature DCSK Modulation Scheme for Cognitive Radio

    Science.gov (United States)

    Quyen, Nguyen Xuan

    The past decade has witnessed a boom of wireless communications which necessitate an increasing improvement of data rate, error-rate performance, bandwidth efficiency, and information security. In this work, we propose a quadrature (IQ) differential chaos-shift keying (DCSK) modulation scheme for the application in cognitive radio (CR), named CR-IQ-DCSK, which offers the above improvement. Chaotic signal is generated in frequency domain and then converted into time domain via an inverse Fourier transform. The real and imaginary components of the frequency-based chaotic signal are simultaneously used in in-phase and quadrature branches of an IQ modulator, where each branch conveys two bits by means of a DCSK-based modulation. Schemes and operating principle of the modulator and demodulator are proposed and described. Analytical BER performance for the proposed schemes over a typical multipath Rayleigh fading channel is derived and verified by numerical simulations. Results show that the proposed scheme outperforms DCSK, CDSK and performs better with the increment of the number of channel paths.

  14. Adaptive protection scheme

    Directory of Open Access Journals (Sweden)

    R. Sitharthan

    2016-09-01

    Full Text Available This paper aims at modelling an electronically coupled distributed energy resource with an adaptive protection scheme. The electronically coupled distributed energy resource is a microgrid framework formed by coupling the renewable energy source electronically. Further, the proposed adaptive protection scheme provides a suitable protection to the microgrid for various fault conditions irrespective of the operating mode of the microgrid: namely, grid connected mode and islanded mode. The outstanding aspect of the developed adaptive protection scheme is that it monitors the microgrid and instantly updates relay fault current according to the variations that occur in the system. The proposed adaptive protection scheme also employs auto reclosures, through which the proposed adaptive protection scheme recovers faster from the fault and thereby increases the consistency of the microgrid. The effectiveness of the proposed adaptive protection is studied through the time domain simulations carried out in the PSCAD⧹EMTDC software environment.

  15. A qualitative study of DRG coding practice in hospitals under the Thai Universal Coverage Scheme

    Directory of Open Access Journals (Sweden)

    Winch Peter J

    2011-04-01

    Full Text Available Abstract Background In the Thai Universal Coverage health insurance scheme, hospital providers are paid for their inpatient care using Diagnosis Related Group-based retrospective payment, for which quality of the diagnosis and procedure codes is crucial. However, there has been limited understandings on which health care professions are involved and how the diagnosis and procedure coding is actually done within hospital settings. The objective of this study is to detail hospital coding structure and process, and to describe the roles of key hospital staff, and other related internal dynamics in Thai hospitals that affect quality of data submitted for inpatient care reimbursement. Methods Research involved qualitative semi-structured interview with 43 participants at 10 hospitals chosen to represent a range of hospital sizes (small/medium/large, location (urban/rural, and type (public/private. Results Hospital Coding Practice has structural and process components. While the structural component includes human resources, hospital committee, and information technology infrastructure, the process component comprises all activities from patient discharge to submission of the diagnosis and procedure codes. At least eight health care professional disciplines are involved in the coding process which comprises seven major steps, each of which involves different hospital staff: 1 Discharge Summarization, 2 Completeness Checking, 3 Diagnosis and Procedure Coding, 4 Code Checking, 5 Relative Weight Challenging, 6 Coding Report, and 7 Internal Audit. The hospital coding practice can be affected by at least five main factors: 1 Internal Dynamics, 2 Management Context, 3 Financial Dependency, 4 Resource and Capacity, and 5 External Factors. Conclusions Hospital coding practice comprises both structural and process components, involves many health care professional disciplines, and is greatly varied across hospitals as a result of five main factors.

  16. Adapting Parcellation Schemes to Study Fetal Brain Connectivity in Serial Imaging Studies

    DEFF Research Database (Denmark)

    Cheng, Xi; Wilm, Jakob; Seshamani, Sharmishtaa

    2013-01-01

    A crucial step in studying brain connectivity is the definition of the Regions Of Interest (ROI's) which are considered as nodes of a network graph. These ROI's identified in structural imaging reflect consistent functional regions in the anatomies being compared. However in serial studies...... demonstrate that the fetal brain network exhibits small-world characteristics and a pattern of increased cluster coefficients and decreased global efficiency. These findings may provide a route to creating a new biomarker for healthy fetal brain development....

  17. Recent Trends in Lower-Limb Robotic Rehabilitation Orthosis: Control Scheme and Strategy for Pneumatic Muscle Actuated Gait Trainers

    Directory of Open Access Journals (Sweden)

    Mohd Azuwan Mat Dzahir

    2014-04-01

    Full Text Available It is a general assumption that pneumatic muscle-type actuators will play an important role in the development of an assistive rehabilitation robotics system. In the last decade, the development of a pneumatic muscle actuated lower-limb leg orthosis has been rather slow compared to other types of actuated leg orthoses that use AC motors, DC motors, pneumatic cylinders, linear actuators, series elastic actuators (SEA and brushless servomotors. However, recent years have shown that the interest in this field has grown exponentially, mainly due to the demand for a more compliant and interactive human-robotics system. This paper presents a survey of existing lower-limb leg orthoses for rehabilitation, which implement pneumatic muscle-type actuators, such as McKibben artificial muscles, rubbertuators, air muscles, pneumatic artificial muscles (PAM or pneumatic muscle actuators (PMA. It reviews all the currently existing lower-limb rehabilitation orthosis systems in terms of comparison and evaluation of the design, as well as the control scheme and strategy, with the aim of clarifying the current and on-going research in the lower-limb robotic rehabilitation field.

  18. Access-Control Schemes for Real-Time and Store-and-Forward Multiple-Access Communication Channels

    Science.gov (United States)

    1980-01-01

    Demand-Assignment TDHA Schemes If the message traffic arriving at the sources is steady, then we can employ a Fixed-Assignment TDMA scheme by dedicating...messages are assumed to be independent and identically 19 1b-- distributed with mean U-1 (seconds). 2.3 The Performance of Demand-Assignment TDHA ...a Type j request, j = 1, 2, is Nj L j =P (K J) ( K ) . (3.8) 3.4 Optimal Allocation of Slots Under a Demand-Assignment TDHA scheme, the channel frame

  19. Corrigendum to ;Numerical dissipation control in high order shock-capturing schemes for LES of low speed flows; [J. Comput. Phys. 307 (2016) 189-202

    Science.gov (United States)

    Kotov, D. V.; Yee, H. C.; Wray, A. A.; Sjögreen, Björn; Kritsuk, A. G.

    2018-01-01

    The authors regret for the typographic errors that were made in equation (4) and missing phrase after equation (4) in the article ;Numerical dissipation control in high order shock-capturing schemes for LES of low speed flows; [J. Comput. Phys. 307 (2016) 189-202].

  20. Effectiveness of two ultrasound-guided transrectal biopsy schemes in the diagnosis of prostate cancer. A randomized study.

    Science.gov (United States)

    Herranz Amo, Felipe; Jara Rascón, José; Cancho Gil, María José; Tabares Jiménez, Juan; Molina Escudero, Roberto; Hernández Fernández, Carlos

    2010-03-01

    To determine whether a 10-core prostate biopsy scheme is superior to the sextant scheme in diagnosing prostate cancer in patients programmed for a first biopsy, with negative rectal digital examination and PSA between 3.5-20 ng/ml. A randomized prospective study was performed comparing two prostate biopsy schemes, with randomization stratification according to prostate volume ( 50 ml). Sample size predetermination yielded a minimum of 304 patients in order to achieve the primary objective. Statistical analysis was carried out on an intent-to-treat basis, using the chi-squared test and uni- and multivariate analysis via logistic regression. Cancer was detected in 27.3% of the cases. A significant association was observed between cancer diagnosis and age (p=0.03), prostate volume (p=0.0001) and ultrasound nodule identification (p=0.0001). No correlation was observed with the total number of cores in the series (p=0.37) or with prostate volume 50 ml (p=0.09). In the multivariate analysis, age > 70 years (p=0.005), prostate volume sextant scheme may prove to be insufficient.

  1. Future efficiency of run of the river hydropower schemes based on climate change scenarios: case study in UK catchments

    Science.gov (United States)

    Pasten Zapata, Ernesto; Moggridge, Helen; Jones, Julie; Widmann, Martin

    2017-04-01

    Run-of-the-River (ROR) hydropower schemes are expected to be importantly affected by climate change as they rely in the availability of river flow to generate energy. As temperature and precipitation are expected to vary in the future, the hydrological cycle will also undergo changes. Therefore, climate models based on complex physical atmospheric interactions have been developed to simulate future climate scenarios considering the atmosphere's greenhouse gas concentrations. These scenarios are classified according to the Representative Concentration Pathways (RCP) that are generated according to the concentration of greenhouse gases. This study evaluates possible scenarios for selected ROR hydropower schemes within the UK, considering three different RCPs: 2.6, 4.5 and 8.5 W/m2 for 2100 relative to pre-industrial values. The study sites cover different climate, land cover, topographic and hydropower scheme characteristics representative of the UK's heterogeneity. Precipitation and temperature outputs from state-of-the-art Regional Climate Models (RCMs) from the Euro-CORDEX project are used as input for a HEC-HMS hydrological model to simulate the future river flow available. Both uncorrected and bias-corrected RCM simulations are analyzed. The results of this project provide an insight of the possible effects of climate change towards the generation of power from the ROR hydropower schemes according to the different RCP scenarios and contrasts the results obtained from uncorrected and bias-corrected RCMs. This analysis can aid on the adaptation to climate change as well as the planning of future ROR schemes in the region.

  2. Iterative Computational Scheme of Studying Electromagnetic Wave Propagation through Dielectric Thin Film Medium

    Directory of Open Access Journals (Sweden)

    E Ugwu

    2016-09-01

    Full Text Available We present an approach to the computation of electromagnetic wave propagation through a dielectric thin film medium using iterative scheme. We used the Green's function technique involving some necessary boundary condition to solve the scalar wave equation. Non-vectorial aspects of the propagating wave through the thin film resulting from the film orientation were considered. The iterative numerical scheme based on the parallel use of Lippmann-Schwinger and Dyson's equations is demonstrated and used judiciously in the computation. The influence of the numerical parameters such as Green's function, thickness of the thin film, dielectric perturbation, Δεp(z and mesh size, Np on the propagating wave for three region of electromagnetic wave were clearly assessed.

  3. A Study on Architecture of Malicious Code Blocking Scheme with White List in Smartphone Environment

    Science.gov (United States)

    Lee, Kijeong; Tolentino, Randy S.; Park, Gil-Cheol; Kim, Yong-Tae

    Recently, the interest and demands for mobile communications are growing so fast because of the increasing prevalence of smartphones around the world. In addition, the existing feature phones were replaced by smartphones and it has widely improved while using the explosive growth of Internet users using smartphones, e-commerce enabled Internet banking transactions and the importance of protecting personal information. Therefore, the development of smartphones antivirus products was developed and launched in order to prevent malicious code or virus infection. In this paper, we proposed a new scheme to protect the smartphone from malicious codes and malicious applications that are element of security threats in mobile environment and to prevent information leakage from malicious code infection. The proposed scheme is based on the white list smartphone application which only allows installing authorized applications and to prevent the installation of malicious and untrusted mobile applications which can possibly infect the applications and programs of smartphones.

  4. Optimum wireless sensor deployment scheme for structural health monitoring: a simulation study

    Science.gov (United States)

    Liu, Chengyin; Fang, Kun; Teng, Jun

    2015-11-01

    With the rapid advancements in smart sensing technology and wireless communication technology, the wireless sensor network (WSN) offers an alternative solution to structural health monitoring (SHM). In WSNs, dense deployment of wireless nodes aids the identification of structural dynamic characteristics, while data transmission is a significant issue since wireless channels typically have a lower bandwidth and a limited power supply. This paper provides a wireless sensor deployment optimization scheme for SHM, in terms of both energy consumption and modal identification accuracy. A spherical energy model is established to formulate the energy consumption within a WSN. The optimal number of sensors and their locations are obtained through solving a multi-objective function with weighting factors on energy consumption and modal identification accuracy using a genetic algorithm (GA). Simulation and comparison results with traditional sensor deployment methods demonstrate the efficiency of the proposed optimization scheme.

  5. Scanning probe microscopy and field emission schemes for studying electron emission from polycrystalline diamond

    OpenAIRE

    Chubenko, Oksana; Baturin, Stanislav S.; Baryshev, Sergey V.

    2016-01-01

    The letter introduces a diagram that rationalizes tunneling atomic force microscopy (TUNA) observations of electron emission from polycrystalline diamonds as described in recent publications. The direct observations of electron emission from grain boundary sites by TUNA could indeed be evidence of electrons originating from grain boundaries under external electric fields. At the same time, from the diagram it follows that TUNA and field emission schemes are complimentary rather than equivalen...

  6. A Study on Efficient Mobile IPv6 Fast Handover Scheme Using Reverse Binding Mechanism

    Science.gov (United States)

    Tolentino, Randy S.; Lee, Kijeong; Kim, Sung-Gyu; Kim, Miso; Park, Byungjoo

    This paper proposes a solution for solving the packet handover issues of MIPv6. We propose an efficient scheme that can support fast handover effectively in standard Mobile IPv6 (MIPv6) by optimizing the associated data and the flow of signal during handover. A new signaling message Reverse Packet Binding Mechanism is defined and utilized to hasten the handover procedure by adding a buffer in access point (AP) and home agent (HA).

  7. Comparative Study on Feature Selection and Fusion Schemes for Emotion Recognition from Speech

    Directory of Open Access Journals (Sweden)

    Santiago Planet

    2012-09-01

    Full Text Available The automatic analysis of speech to detect affective states may improve the way users interact with electronic devices. However, the analysis only at the acoustic level could be not enough to determine the emotion of a user in a realistic scenario. In this paper we analyzed the spontaneous speech recordings of the FAU Aibo Corpus at the acoustic and linguistic levels to extract two sets of features. The acoustic set was reduced by a greedy procedure selecting the most relevant features to optimize the learning stage. We compared two versions of this greedy selection algorithm by performing the search of the relevant features forwards and backwards. We experimented with three classification approaches: Naïve-Bayes, a support vector machine and a logistic model tree, and two fusion schemes: decision-level fusion, merging the hard-decisions of the acoustic and linguistic classifiers by means of a decision tree; and feature-level fusion, concatenating both sets of features before the learning stage. Despite the low performance achieved by the linguistic data, a dramatic improvement was achieved after its combination with the acoustic information, improving the results achieved by this second modality on its own. The results achieved by the classifiers using the parameters merged at feature level outperformed the classification results of the decision-level fusion scheme, despite the simplicity of the scheme. Moreover, the extremely reduced set of acoustic features obtained by the greedy forward search selection algorithm improved the results provided by the full set.

  8. Study on electromagnetic plasma propulsion using rotating magnetic field acceleration scheme

    Science.gov (United States)

    Furukawa, T.; Takizawa, K.; Kuwahara, D.; Shinohara, S.

    2017-04-01

    As one of the electromagnetic plasma acceleration systems, we have proposed a rotating magnetic field (RMF) acceleration scheme to overcome the present problem of direct plasma-electrode interactions, leading to a short lifetime with a poor plasma performance due to contamination. In this scheme, we generate a plasma by a helicon wave excited by a radio frequency (rf) antenna which has no direct-contact with a plasma. Then, the produced plasma is accelerated by the axial Lorentz force fz = jθ × Br (jθ is an azimuthal current induced by RMF, and Br is an external radial magnetic field). Erosion of electrodes and contamination are not expected in this total system since RMF coils and an rf antenna do not have contact with the plasma directly. Here, we have measured the plasma parameters (electron density ne and axial ion velocity vi) to demonstrate this RMF acceleration scheme by the use of AC currents in two sets of opposing coils to generate a RMF. The maximum increasing rate Δvi /vi was ˜28% (maximum vi of ˜3 km/s), while the density increasing rate of Δne/ne is ˜ 70% in the case of a RMF current frequency fRMF of 3 MHz, which showed a better plasma performance than that with fRMF = 5 MHz. Moreover, thrust characteristics such as a specific impulse and a thrust efficiency were discussed, although a target plasma was not optimized.

  9. Is MGNREG Scheme complementary to fishing activities? A study on some selected states of India

    Directory of Open Access Journals (Sweden)

    Chiranjib Neogi

    2016-01-01

    Full Text Available Freshwater fish output is taken as a proxy variable for empirical assessment of indirect benefits in terms of enhanced quantity of freshwater fish (output cultivation. It is not unlikely to assess empirically the productivity of subsidized public scheme when rural development or rural asset generations are underlined in the said scheme, MGNREG Act, 2005. Rainwater harvesting is a major component part of the scheme since about 49.5 per cent of the total fund is already utilized on water conservation and obviously it has an impact on the cultivation of freshwater fish output. Time series data on annual expenditure on MGNREG and corresponding freshwater fish output at the state level are taken during the period 2006-07 to 2013-14 for 16 major Indian states. Fixed effect model and random effect models are being applied and the Hausman specification test suggests that fixed effect model is more appropriate than random effect model. Significant differences among the intercepts of the selected states are revealed as per F test. The results of fixed effect panel regression establish that fish output is enhanced by 0.000257 thousand tones or 0.26 tones if MGNREG expenditure rises by one crore or 10 million rupees.

  10. A Study of an Iterative Channel Estimation Scheme of FS-FBMC System

    Directory of Open Access Journals (Sweden)

    YongJu Won

    2017-01-01

    Full Text Available A filter bank multicarrier on offset-quadrature amplitude modulation (FBMC/OQAM system is an alternative multicarrier modulation scheme that does not need cyclic prefix (CP even in the presence of a multipath fading channel by the properties of prototype filter. The FBMC/OQAM system can be implemented either by using the poly-phase network with fast fourier transform (PPN-FFT or by using the extended FFT on a frequency-spreading (FS domain. In this paper, we propose an iterative channel estimation scheme for each sub channel of a FBMC/OQAM system over a frequency-spreading domain. The proposed scheme first estimates the channel using the received pilot signal in the subchannel domain and interpolates the estimated channel to fine frequency-spreading domain. Then the channel compensated FS domain pilot is despread again to modify the channel state information (CSI estimation. Computer simulation shows that the proposed method outperforms the conventional FBMC/OQAM channel estimator in a frequency selective channel.

  11. Audit study of the new hospitalization for assessment scheme for forensic mental health in Japan.

    Science.gov (United States)

    Shiina, Akihiro; Iyo, Masaomi; Hirata, Toyoaki; Igarashi, Yoshito

    2015-06-22

    To clarify the components of hospitalization for assessment (HfA) and the management changes from the beginning of the scheme to the present. This study is composed of two surveys. In 2013 survey, we created two paper questionnaires (facility and case questionnaires) for psychiatrists working in psychiatric hospitals accepting HfA patients. Questionnaires were sent to 205 hospitals that were identified as accepting the HfA cases, and responses were requested via mail. The facility questionnaire was designed to clarify the following specifications and characteristics of each facility: the facility organizer (public sector or private hospital), and the number of beds, psychiatrists, psychiatric nurses, occupational therapists, psychiatric social workers, psychotherapists, public health nurses, and patients treated through HfA during the survey period. The case questionnaire was then used to collect data of the patients under HfA based on the Medical Treatment and Supervision (MTS) Act who were discharged between July 1, 2012 and June 30, 2013. Gathered information included: legal information of each case, demographic data, past history of the offenders, issued offense and the relationship to the victim, information regarding past psychiatric testimonies, psychiatric diagnoses, contents of the treatment during HfA, information regarding seclusion and restraint during the HfA, the verdict of the District Court panel, and so forth. Next, we compared those results with relevant data obtained in 2007. The 2007 survey comprised data of HfA patients from July 15, 2005 (the date the MTS Act was enforced) to January 15, 2007. We obtained 171 cases, approximately a half of whole contemporary cases of HfA, from 134 facilities, of which 46 were national, prefectural, or semi-official hospitals, and 88 were private hospitals, in 2013 survey. The majority of subjects were male, schizophrenic, and experienced previous psychiatric treatment. The most frequent type of the offense was

  12. Ghana's National Health insurance scheme and maternal and child health: a mixed methods study.

    Science.gov (United States)

    Singh, Kavita; Osei-Akoto, Isaac; Otchere, Frank; Sodzi-Tettey, Sodzi; Barrington, Clare; Huang, Carolyn; Fordham, Corinne; Speizer, Ilene

    2015-03-17

    Ghana is attracting global attention for efforts to provide health insurance to all citizens through the National Health Insurance Scheme (NHIS). With the program's strong emphasis on maternal and child health, an expectation of the program is that members will have increased use of relevant services. This paper uses qualitative and quantitative data from a baseline assessment for the Maternal and Newborn errals Evaluation from the Northern and Central Regions to describe women's experiences with the NHIS and to study associations between insurance and skilled facility delivery, antenatal care and early care-seeking for sick children. The assessment included a quantitative household survey (n = 1267 women), a quantitative community leader survey (n = 62), qualitative birth narratives with mothers (n = 20) and fathers (n = 18), key informant interviews with health care workers (n = 5) and focus groups (n = 3) with community leaders and stakeholders. The key independent variables for the quantitative analyses were health insurance coverage during the past three years (categorized as all three years, 1-2 years or no coverage) and health insurance during the exact time of pregnancy. Quantitative findings indicate that insurance coverage during the past three years and insurance during pregnancy were associated with greater use of facility delivery but not ANC. Respondents with insurance were also significantly more likely to indicate that an illness need not be severe for them to take a sick child for care. The NHIS does appear to enable pregnant women to access services and allow caregivers to seek care early for sick children, but both the quantitative and qualitative assessments also indicated that the poor and least educated were less likely to have insurance than their wealthier and more educated counterparts. Findings from the qualitative interviews uncovered specific challenges women faced regarding registration for the NHIS and other

  13. A comparative study of field-oriented control and direct-torque control of induction motors using an adaptive flux observer

    Directory of Open Access Journals (Sweden)

    Chikhi Abdesselam

    2010-01-01

    Full Text Available This paper presents a comparative study of field-oriented control (IFOC and direct-torque control (DTC of induction motors using an adaptive flux observer. The main characteristics of field-oriented control and direct torque control schemes are studied by simulation, emphasizing their advantages and disadvantages. The performances of the two control schemes are evaluated in terms of torque, current ripples and transient responses to load toque variations. We can nevertheless observe a slight advance of DTC scheme compared to FOC scheme regarding the dynamic flux control performance and the implementation complexity. Consequently, the choice of one or the other scheme will depend mainly on specific requirements of the application.

  14. Design of a Three-Phase Statcom-Based Inductive Static VAR Compensator Using DC Capacitor Voltage Control Scheme

    OpenAIRE

    Abdulkareem Mokif Obais; Jagadeesh Pasupuleti

    2013-01-01

    In this study, a three-phase continuously controlled harmonic-free inductive static VAR compensator is presented. The compensator is built of a three-phase voltage source inverter based statcom. The phase currents of this compensator are linearly and continuously controlled by the statcom DC capacitor voltage. The control strategy is outlined by a process of forcing the capacitor voltage to follow a certain reference voltage which can be varied linearly from its maximum to its minimum values ...

  15. Bonus Schemes and Trading Activity

    NARCIS (Netherlands)

    Pikulina, E.S.; Renneboog, L.D.R.; Ter Horst, J.R.; Tobler, P.N.

    2013-01-01

    Abstract: Little is known about how different bonus schemes affect traders’ propensity to trade and which bonus schemes improve traders’ performance. We study the effects of linear versus threshold (convex) bonus schemes on traders’ behavior. Traders purchase and sell shares in an experimental stock

  16. Bonus schemes and trading activity

    NARCIS (Netherlands)

    Pikulina, E.S.; Renneboog, L.D.R.; ter Horst, J.R.; Tobler, P.N.

    2014-01-01

    Little is known about how different bonus schemes affect traders' propensity to trade and which bonus schemes improve traders' performance. We study the effects of linear versus threshold bonus schemes on traders' behavior. Traders buy and sell shares in an experimental stock market on the basis of

  17. A measure for the efficiency of water use and its determinants, a case study of small-scale irrigation schemes in North-West Province, South Africa

    NARCIS (Netherlands)

    Speelman, S.; Haese, D' M.F.C.; Buysse, J.; Haese, D' L.

    2008-01-01

    This paper analyses the efficiency with which water is used in small-scale irrigation schemes in North-West Province in South Africa and studies its determinants. In the study area, small-scale irrigation schemes play an important role in rural development, but the increasing pressure on water

  18. Persons with Multiple Disabilities Exercise Adaptive Response Schemes with the Help of Technology-Based Programs: Three Single-Case Studies

    Science.gov (United States)

    Lancioni, Giulio E.; Singh, Nirbhay N.; O'Reilly, Mark F.; Sigafoos, Jeff; Oliva, Doretta; Campodonico, Francesca; Lang, Russell

    2012-01-01

    The present three single-case studies assessed the effectiveness of technology-based programs to help three persons with multiple disabilities exercise adaptive response schemes independently. The response schemes included (a) left and right head movements for a man who kept his head increasingly static on his wheelchair's headrest (Study I), (b)…

  19. Evaluation of rock mass classification schemes: a case study from the Bowen Basin, Australia

    Science.gov (United States)

    Brook, Martin; Hebblewhite, Bruce; Mitra, Rudrajit

    2016-04-01

    The development of an accurate engineering geological model and adequate knowledge of spatial variation in rock mass conditions are important prerequisites for slope stability analyses, tunnel design, mine planning and risk management. Rock mass classification schemes such as Rock Mass Rating (RMR), Coal Mine Roof Rating (CMRR), Q-system and Roof Strength Index (RSI) have been used for a range of engineering geological applications, including transport tunnels, "hard rock" mining and underground and open-cut coal mines. Often, rock mass classification schemes have been evaluated on subaerial exposures, where weathering has affected joint characteristics and intact strength. In contrast, the focus of this evaluation of the above classification schemes is an underground coal mine in the Bowen Basin, central Queensland, Australia, 15 km east of the town of Moranbah. Rock mass classification was undertaken at 68 sites across the mine. Both the target coal seam and overlying rock show marked spatial variability in terms of RMR, CMRR and Q, but RSI showed limited sensitivity to changes in rock mass condition. Relationships were developed between different parameters with varying degrees of success. A mine-wide analysis of faulting was undertaken, and compared with in situ stress field and local-scale measurements of joint and cleat. While there are no unequivocal relationships between rock mass classification parameters and faulting, a central graben zone shows heterogeneous rock mass properties. The corollary is that if geological features can be accurately defined by remote sensing technologies, then this can assist in predicting rock mass conditions and risk management ahead of development and construction.

  20. Mixed-frame and stationary-frame repetitive control schemes for compensating typical load and grid harmonics

    DEFF Research Database (Denmark)

    Loh, P.; Tang, Y.; Blaabjerg, Frede

    2011-01-01

    In this study, repetitive current controllers operating in either the mixed or stationary frame are proposed for high-precision reference tracking and disturbance rejection of power converters. Both controllers use a proportional-resonant regulator in the stationary frame for regulating...... the positive- and negative-sequence fundamental currents, which are known to directly influence the flow of active and reactive power in most energy conversion systems. Moreover, for the tracking or compensation of harmonics, the controllers include a repetitive control path in either the synchronous...... or stationary frame, whose inherent feedback and feedforward structure is proven to resemble a bank of resonant filters in either reference frames. Unlike other existing controllers, the proposed repetitive controllers function by introducing multiple resonant peaks at only those harmonic frequencies typically...

  1. APPLICATION OF QUALITY INDEX METHOD (QIM SCHEME IN SHELFLIFE STUDY OF ANGLERFISH (Lophius piscatorius

    Directory of Open Access Journals (Sweden)

    L. Pennisi

    2011-01-01

    Full Text Available The aim was to evaluate a Quality Index Method (QIM scheme for fresh Anglerfish (Lophius piscatorius. Anglerfish were stored at 0±2 °C on ice up to 9 days. Total Mesophilic Counts (TMC, Total Psychrophilic Counts (TPC and counts of Specific Spoilage Organisms (SSOs were done. An high correlation between the Quality Index (QI and storage time on ice and between the Quality Index (QI and H2S-producing bacteria counts was found. The remaining storage time could be estimated with accuracy of ±1.5 days when the Anglerfish were evaluated with QIM.

  2. The scheme machine: A case study in progress in design derivation at system levels

    Science.gov (United States)

    Johnson, Steven D.

    1995-01-01

    The Scheme Machine is one of several design projects of the Digital Design Derivation group at Indiana University. It differs from the other projects in its focus on issues of system design and its connection to surrounding research in programming language semantics, compiler construction, and programming methodology underway at Indiana and elsewhere. The genesis of the project dates to the early 1980's, when digital design derivation research branched from the surrounding research effort in programming languages. Both branches have continued to develop in parallel, with this particular project serving as a bridge. However, by 1990 there remained little real interaction between the branches and recently we have undertaken to reintegrate them. On the software side, researchers have refined a mathematically rigorous (but not mechanized) treatment starting with the fully abstract semantic definition of Scheme and resulting in an efficient implementation consisting of a compiler and virtual machine model, the latter typically realized with a general purpose microprocessor. The derivation includes a number of sophisticated factorizations and representations and is also deep example of the underlying engineering methodology. The hardware research has created a mechanized algebra supporting the tedious and massive transformations often seen at lower levels of design. This work has progressed to the point that large scale devices, such as processors, can be derived from first-order finite state machine specifications. This is roughly where the language oriented research stops; thus, together, the two efforts establish a thread from the highest levels of abstract specification to detailed digital implementation. The Scheme Machine project challenges hardware derivation research in several ways, although the individual components of the system are of a similar scale to those we have worked with before. The machine has a custom dual-ported memory to support garbage collection

  3. Study on development of Grid code and operation scheme of Jeju Island with high wind penetration

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Seung-Il; Pyo, Gi-Chan; Park, Jin-Woo

    2010-09-15

    Lots of large-scale wind generation are currently being commissioned, with more planned for the near future in Jeju Island of Korea. The large-scale wind generation, however, could have adverse impacts on stable operation of power system. Accordingly for the stable operation of Jeju power system, the necessity to limit the wind installation is brought up recently and new wind power projects are restricted for now. To increase the wind penetration in Jeju Island, solutions in two respects is presented in this paper; Establishment of grid code for wind generation and development of coordinated operation schemes of Jeju power system.

  4. A Comparative Study of Mindfulness Efficiency Based on Islamic-Spiritual Schemes and Group Cognitive Behavioral Therapy on Reduction of Anxiety and Depression in Pregnant Women.

    Science.gov (United States)

    Aslami, Elahe; Alipour, Ahmad; Najib, Fatemeh Sadat; Aghayosefi, Alireza

    2017-04-01

    Anxiety and depression during the pregnancy period are among the factors affecting the pregnancy undesirable outcomes and delivery. One way of controlling anxiety and depression is mindfulness and cognitive behavioral therapy. The purpose of this study was to compare the efficiency of mindfulness based on the Islamic-spiritual schemas and group cognitive behavioral therapy on reduction of anxiety and depression in pregnant women. The research design was semi-experimental in the form of pretest-posttest using a control group. Among the pregnant women in the 16th to 32nd weeks of pregnancy who referred to the health center, 30 pregnant women with high anxiety level and 30 pregnant women with high depression participated in the research. Randomly 15 participants with high depression and 15 participants with high anxiety were considered in the intervention group under the treatment of mindfulness based on Islamic-spiritual schemes. In addition, 15 participants with high scores regarding depression and 15 with high scores in anxiety were considered in the other group. .The control group consisted of 15 pregnant women with high anxiety and depression. Beck anxiety-depression questionnaire was used in two steps of pre-test and post-test. Data were analyzed using SPSS, version 20, and P≤0.05 was considered as significant. The results of multivariate analysis of variance test and tracking Tokey test showed that there was a significant difference between the mean scores of anxiety and depression in the two groups of mindfulness based on spiritual- Islamic scheme (Pcognitive behavioral therapy with each other (Ptherapy methods were effective in reduction of anxiety and depression of pregnant women, but the effect of mindfulness based on spiritual- Islamic schemes was more.

  5. A study of design approach of spreading schemes for viral marketing based on human dynamics

    Science.gov (United States)

    Yang, Jianmei; Zhuang, Dong; Xie, Weicong; Chen, Guangrong

    2013-12-01

    Before launching a real viral marketing campaign, it is needed to design a spreading scheme by simulations. Based on a categorization of spreading patterns in real world and models, we point out that the existing research (especially Yang et al. (2010) Ref. [16]) implicitly assume that if a user decides to post a received message (is activated), he/she will take the reposting action promptly (Prompt Action After Activation, or PAAA). After a careful analysis on a real dataset however, it is found that the observed time differences between action and activation exhibit a heavy-tailed distribution. A simulation model for heavy-tailed pattern is then proposed and performed. Similarities and differences of spreading processes between the heavy-tailed and PAAA patterns are analyzed. Consequently, a more practical design approach of spreading scheme for viral marketing on QQ platform is proposed. The design approach can be extended and applied to the contexts of non-heavy-tailed pattern, and viral marketing on other instant messaging platforms.

  6. Study of different reaction schemes for the enzymatic synthesis of polyglycerol polyricinoleate.

    Science.gov (United States)

    Ortega-Requena, Salvadora; Gómez, José L; Bastida, Josefa; Máximo, Fuensanta; Montiel, María C; Murcia, María D

    2014-08-01

    Different strategies for the solvent-free enzymatic production of polyglycerol polyricinoleate (PGPR) were explored in an attempt to simplify and improve the process. Besides the conventional procedure (obtaining polyricinoleic acid, followed by its esterification with polyglycerol), two alternative methods are proposed: (1) reversing the synthesis order, i.e. esterification of polyglycerol with ricinoleic acid and then the condensation of ricinoleic acid with the previously obtained polyglycerol ester; and (2) the enzymatic synthesis of PGPR in a single-step process. The reaction sequences were carried out in an open-air reactor with free and immobilised lipases (triacylglycerol acylhydrolases, E.C. 3.1.1.3): Candida rugosa lipase to obtain polyricinoleic acid and Rhizopus oryzae lipase for the esterification of polyglycerol with the carboxyl group of ricinoleic or polyricinoleic acid. A co-immobilised derivative containing both lipases was used to catalyse the single-stage scheme. The three processes were carried out in a vacuum reactor, obtaining in every case PGPR that complied with the legal specifications of the European Community and recommendations provided in the Food Chemical Codex. The results demonstrate that all three protocols are viable for the enzymatic synthesis of PGPR and require similar reaction times. The single-stage scheme is easier to carry out. © 2014 Society of Chemical Industry.

  7. Succesful labelling schemes

    DEFF Research Database (Denmark)

    Juhl, Hans Jørn; Stacey, Julia

    2001-01-01

    It is usual practice to evaluate the success of a labelling scheme by looking at the awareness percentage, but in many cases this is not sufficient. The awareness percentage gives no indication of which of the consumer segments that are aware of and use labelling schemes and which do not....... In the spring of 2001 MAPP carried out an extensive consumer study with special emphasis on the Nordic environmentally friendly label 'the swan'. The purpose was to find out how much consumers actually know and use various labelling schemes. 869 households were contacted and asked to fill in a questionnaire....... 664 households returned a completed questionnaire. There were five answering categories for each label in the questionnaire: * have not seen the label before. * I have seen the label before but I do not know the precise contents of the labelling scheme. * I have seen the label before, I do not know...

  8. Maximum power extraction under different vector-control schemes and grid-synchronization strategy of a wind-driven Brushless Doubly-Fed Reluctance Generator.

    Science.gov (United States)

    Mousa, Mohamed G; Allam, S M; Rashad, Essam M

    2018-01-01

    This paper proposes an advanced strategy to synchronize the wind-driven Brushless Doubly-Fed Reluctance Generator (BDFRG) to the grid-side terminals. The proposed strategy depends mainly upon determining the electrical angle of the grid voltage, θ v and using the same transformation matrix of both the power winding and grid sides to ensure that the generated power-winding voltage has the same phase-sequence of the grid-side voltage. On the other hand, the paper proposes a vector-control (power-winding flux orientation) technique for maximum wind-power extraction under two schemes summarized as; unity power-factor operation and minimum converter-current. Moreover, a soft-starting method is suggested to avoid the employed converter over-current. The first control scheme is achieved by adjusting the command power-winding reactive power at zero for a unity power-factor operation. However, the second scheme depends on setting the command d-axis control-winding current at zero to maximize the ratio of the generator electromagnetic-torque per the converter current. This enables the system to get a certain command torque under minimum converter current. A sample of the obtained simulation and experimental results is presented to check the effectiveness of the proposed control strategies. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  9. Design and Performance Evaluation of Cooperative Retransmission Scheme for Reliable Multicast Services in Cellular Controlled P2P Networks

    DEFF Research Database (Denmark)

    Zhang, Qi; Fitzek, F.H.P.; Iversen, Villy Bæk

    2007-01-01

    Reliable multicast applications such as software distribution, data distribution and replication and mailing list delivery, etc. [1] are getting more and more interests from network and service providers. The conventional error/loss recovery schemes are not efficient when they are applied to mult...

  10. The importance of temporal and spatial vegetation structure information in biotope mapping schemes: a case study in Helsingborg, Sweden.

    Science.gov (United States)

    Gao, Tian; Qiu, Ling; Hammer, Mårten; Gunnarsson, Allan

    2012-02-01

    Temporal and spatial vegetation structure has impact on biodiversity qualities. Yet, current schemes of biotope mapping do only to a limited extend incorporate these factors in the mapping. The purpose of this study is to evaluate the application of a modified biotope mapping scheme that includes temporal and spatial vegetation structure. A refined scheme was developed based on a biotope classification, and applied to a green structure system in Helsingborg city in southern Sweden. It includes four parameters of vegetation structure: continuity of forest cover, age of dominant trees, horizontal structure, and vertical structure. The major green structure sites were determined by interpretation of panchromatic aerial photographs assisted with a field survey. A set of biotope maps was constructed on the basis of each level of modified classification. An evaluation of the scheme included two aspects in particular: comparison of species richness between long-continuity and short-continuity forests based on identification of woodland continuity using ancient woodland indicators (AWI) species and related historical documents, and spatial distribution of animals in the green space in relation to vegetation structure. The results indicate that (1) the relationship between forest continuity: according to verification of historical documents, the richness of AWI species was higher in long-continuity forests; Simpson's diversity was significantly different between long- and short-continuity forests; the total species richness and Shannon's diversity were much higher in long-continuity forests shown a very significant difference. (2) The spatial vegetation structure and age of stands influence the richness and abundance of the avian fauna and rabbits, and distance to the nearest tree and shrub was a strong determinant of presence for these animal groups. It is concluded that continuity of forest cover, age of dominant trees, horizontal and vertical structures of vegetation

  11. Assessing ocean vertical mixing schemes for the study of climate change

    Science.gov (United States)

    Howard, A. M.; Lindo, F.; Fells, J.; Tulsee, V.; Cheng, Y.; Canuto, V.

    2014-12-01

    Climate change is a burning issue of our time. It is critical to know the consequences of choosing "business as usual" vs. mitigating our emissions for impacts e.g. ecosystem disruption, sea-level rise, floods and droughts. To make predictions we must model realistically each component of the climate system. The ocean must be modeled carefully as it plays a critical role, including transporting heat and storing heat and dissolved carbon dioxide. Modeling the ocean realistically in turn requires physically based parameterizations of key processes in it that cannot be explicitly represented in a global climate model. One such process is vertical mixing. The turbulence group at NASA-GISS has developed a comprehensive new vertical mixing scheme (GISSVM) based on turbulence theory, including surface convection and wind shear, interior waves and double-diffusion, and bottom tides. The GISSVM is tested in stand-alone ocean simulations before being used in coupled climate models. It is also being upgraded to more faithfully represent the physical processes. To help assess mixing schemes, students use data from NASA-GISS to create visualizations and calculate statistics including mean bias and rms differences and correlations of fields. These are created and programmed with MATLAB. Results with the commonly used KPP mixing scheme and the present GISSVM and candidate improved variants of GISSVM will be compared between stand-alone ocean models and coupled models and observations. This project introduces students to modeling of a complex system, an important theme in contemporary science and helps them gain a better appreciation of climate science and a new perspective on it. They also gain familiarity with MATLAB, a widely used tool, and develop skills in writing and understanding programs. Moreover they contribute to the advancement of science by providing information that will help guide the improvement of the GISSVM and hence of ocean and climate models and ultimately our

  12. A study of practical proxy reencryption with a keyword search scheme considering cloud storage structure.

    Science.gov (United States)

    Lee, Sun-Ho; Lee, Im-Yeong

    2014-01-01

    Data outsourcing services have emerged with the increasing use of digital information. They can be used to store data from various devices via networks that are easy to access. Unlike existing removable storage systems, storage outsourcing is available to many users because it has no storage limit and does not require a local storage medium. However, the reliability of storage outsourcing has become an important topic because many users employ it to store large volumes of data. To protect against unethical administrators and attackers, a variety of cryptography systems are used, such as searchable encryption and proxy reencryption. However, existing searchable encryption technology is inconvenient for use in storage outsourcing environments where users upload their data to be shared with others as necessary. In addition, some existing schemes are vulnerable to collusion attacks and have computing cost inefficiencies. In this paper, we analyze existing proxy re-encryption with keyword search.

  13. A comparative study of scalable video coding schemes utilizing wavelet technology

    Science.gov (United States)

    Schelkens, Peter; Andreopoulos, Yiannis; Barbarien, Joeri; Clerckx, Tom; Verdicchio, Fabio; Munteanu, Adrian; van der Schaar, Mihaela

    2004-02-01

    Video transmission over variable-bandwidth networks requires instantaneous bit-rate adaptation at the server site to provide an acceptable decoding quality. For this purpose, recent developments in video coding aim at providing a fully embedded bit-stream with seamless adaptation capabilities in bit-rate, frame-rate and resolution. A new promising technology in this context is wavelet-based video coding. Wavelets have already demonstrated their potential for quality and resolution scalability in still-image coding. This led to the investigation of various schemes for the compression of video, exploiting similar principles to generate embedded bit-streams. In this paper we present scalable wavelet-based video-coding technology with competitive rate-distortion behavior compared to standardized non-scalable technology.

  14. A Fuzzy Logic Study of Weighting Scheme for Satellite-Laser-Ranging Global Tracking Network

    Science.gov (United States)

    VIGO, I. M.; SOTO, J.; FLORES, A.; FERRANDIZ, J. M.

    2001-12-01

    In satellite-laser-ranging (SLR) data processing, oftentimes the weighting scheme of station observations is subjective or even quasi-arbitrary, and a somewhat arbitrary cutoff of say, 1m is applied prior to the data processing. This practice leaves something to be decided in terms of making optimal use of the available data. We intend to improve the situation by applying fuzzy-logic techniques in the editing and weighting of the data in an objective way. Many authors (e.g., Katja Heine (2001) and others in the Proceedings of the First International Symposium on Robust Statistics and Fuzzy Techniques in Geodesy an GIS ) have demonstrated the potential utility of the fuzzy logic methods in geodetic problems. The aim of this work is to test a fuzzy logic method as a tool to provide a reliable criteria for weighting scheme for satellite-laser-ranging (SLR) station observations, seeking to optimize their contribution to the precise orbit determination (POD) problem. The data regarding the stations were provided by the International Laser Ranging Service, NASA/CDDIS provided the satellite data for testing the method. The software for processing the data is GEODYN II provided by NASA/GSFC. Factors to be considered in the fuzzy-logic clustering are: the total number of LAGEOS passes during the past 12 months, the stability measure of short and long term biases, the percentage of LAGEOS normal points that were accepted in CSR weekly LAGEOS analysis, and the RMS uncertainty of the station coordinates. Fuzzy logic statistical method allows classifying the stations through a clear membership degree to each station group. This membership degree translates into a suitable weight to be assigned to observations from each station in the global solution. The first tests carried out show improvements in the RMS of the global POD solution as well as individual stations, to within a few millimeters. We expect further work would lead to further improvements.

  15. Implementation of an insecticide-treated net subsidy scheme under a public-private partnership for malaria control in Tanzania – challenges in implementation

    Directory of Open Access Journals (Sweden)

    Gilson Lucy

    2009-08-01

    Full Text Available Abstract Background In the past decade there has been increasing visibility of malaria control efforts at the national and international levels. The factors that have enhanced this scenario are the availability of proven interventions such as artemisinin-based combination therapy, the wide scale use of insecticide-treated nets (ITNs and a renewed emphasis in indoor residual house-spraying. Concurrently, there has been a window of opportunity of financial commitments from organizations such as the Global Fund for HIV/AIDS, Tuberculosis and Malaria (GFATM, the President's Malaria Initiative and the World Bank Booster programme. Methods The case study uses the health policy analysis framework to analyse the implementation of a public-private partnership approach embarked upon by the government of Tanzania in malaria control – 'The Tanzania National Voucher Scheme'- and in this synthesis, emphasis is on the challenges faced by the scheme during the pre-implementation (2001 – 2004 and implementation phases (2004 – 2005. Qualitative research tools used include: document review, interview with key informants, stakeholder's analysis, force-field analysis, time line of events, policy characteristic analysis and focus group discussions. The study is also complemented by a cross-sectional survey, which was conducted at the Rufiji Health Demographic Surveillance Site, where a cohort of women of child-bearing age were followed up regarding access and use of ITNs. Results The major challenges observed include: the re-introduction of taxes on mosquito nets and related products, procurement and tendering procedures in the implementation of the GFATM, and organizational arrangements and free delivery of mosquito nets through a Presidential initiative. Conclusion The lessons gleaned from this synthesis include: (a the consistency of the stakeholders with a common vision, was an important strength in overcoming obstacles, (b senior politicians often steered

  16. Implementation of an insecticide-treated net subsidy scheme under a public-private partnership for malaria control in Tanzania--challenges in implementation.

    Science.gov (United States)

    Njau, Ritha J A; de Savigny, Don; Gilson, Lucy; Mwageni, Eleuther; Mosha, Franklin W

    2009-08-21

    In the past decade there has been increasing visibility of malaria control efforts at the national and international levels. The factors that have enhanced this scenario are the availability of proven interventions such as artemisinin-based combination therapy, the wide scale use of insecticide-treated nets (ITNs) and a renewed emphasis in indoor residual house-spraying. Concurrently, there has been a window of opportunity of financial commitments from organizations such as the Global Fund for HIV/AIDS, Tuberculosis and Malaria (GFATM), the President's Malaria Initiative and the World Bank Booster programme. The case study uses the health policy analysis framework to analyse the implementation of a public-private partnership approach embarked upon by the government of Tanzania in malaria control - 'The Tanzania National Voucher Scheme'- and in this synthesis, emphasis is on the challenges faced by the scheme during the pre-implementation (2001 - 2004) and implementation phases (2004 - 2005). Qualitative research tools used include: document review, interview with key informants, stakeholder's analysis, force-field analysis, time line of events, policy characteristic analysis and focus group discussions. The study is also complemented by a cross-sectional survey, which was conducted at the Rufiji Health Demographic Surveillance Site, where a cohort of women of child-bearing age were followed up regarding access and use of ITNs. The major challenges observed include: the re-introduction of taxes on mosquito nets and related products, procurement and tendering procedures in the implementation of the GFATM, and organizational arrangements and free delivery of mosquito nets through a Presidential initiative. The lessons gleaned from this synthesis include: (a) the consistency of the stakeholders with a common vision, was an important strength in overcoming obstacles, (b) senior politicians often steered the policy agenda when the policy in question was a 'crisis event

  17. control study from India

    Directory of Open Access Journals (Sweden)

    Amitesh Aggarwal

    2014-03-01

    Full Text Available Introduction: The role of the conventional risk factors in premature coronary artery disease (CAD after eliminating the confounding variability of smoking has not been evaluated. This study was conducted to identify role of traditional risk factors in smokers with premature CAD.Methods: The case records of patients presenting acutely with premature CAD during the period 2007-2010 were analyzed retrospectively. Age, sex and smoking matched controls were selected from same time period. Data records were obtained for family history, alcohol, waist size, blood pressure, hypertension, blood sugar, lipid profile and presence of cutaneous markers for both groups and analyzed using statistical software.Results: 234 smokers with CAD and 122 smokers without CAD were included in groups 1 and 2, respectively. The patients in group 1 had significantly increased prevalence of hypertension, diabetes mellitus, metabolic syndrome, dyslipidemia and central obesity. There was no difference in prevalence of family history of CAD, arcus juvenilis and baldness. We found statistically significant association of hypertension, DM and metabolic syndrome in young smokers with premature acute CAD in Indian population as compared to young smokers without CAD.Conclusion: In young smokers, presence of hypertension, central obesity, diabetes mellitus and metabolic syndrome identifies a subset at increased risk for future acute CAD requiring more rigorous follow up and treatment.

  18. The extrapolated explicit midpoint scheme for variable order and step size controlled integration of the Landau-Lifschitz-Gilbert equation

    Science.gov (United States)

    Exl, Lukas; Mauser, Norbert J.; Schrefl, Thomas; Suess, Dieter

    2017-10-01

    A practical and efficient scheme for the higher order integration of the Landau-Lifschitz-Gilbert (LLG) equation is presented. The method is based on extrapolation of the two-step explicit midpoint rule and incorporates adaptive time step and order selection. We make use of a piecewise time-linear stray field approximation to reduce the necessary work per time step. The approximation to the interpolated operator is embedded into the extrapolation process to keep in step with the hierarchic order structure of the scheme. We verify the approach by means of numerical experiments on a standardized NIST problem and compare with a higher order embedded Runge-Kutta formula. The efficiency of the presented approach increases when the stray field computation takes a larger portion of the costs for the effective field evaluation.

  19. Transferability Of DEMETER. A Case Study Of The Irrigation Scheme Of Veiga De Chaves

    Science.gov (United States)

    Baptista, A.; Sousa, V.

    2006-08-01

    DEMETER is a research and demonstration project, designed to assess and demonstrate how the integration of Earth Observation techniques in routine Irrigation Advisory Services can improve efficiency in the use of irrigation water. The objectives of this paper are: (1) to analyze the interest in the feasibility of transferring the DEMETER technology to the irrigation scheme of Chaves: (2) to identify the factors that, in general, favour the usefulness of this technology. The irrigation infrastructure and methods, the size and number of irrigation parcels and the main crops grown at the irrigation scheme of Chaves have been recorded. Also a socio-economic description has been done. Field visits, interviews with the staff of water association, and an inquiry to a sample of 107 farmers were made. The main results are: each farmer pays an area based annual fee, independent of the amount of water used for irrigation; most of the irrigated parcels are of very small size, 0.3 ha in average, mostly irrigated by surface methods; the most representative crops grown are potato, forage maize, and several different horticultural crops; an important part of the production is for self-consumption. The farmers are aging and the new generations prefer other jobs than agriculture. A considerable number of farmers have another job in the nearby cities. The small size of the irrigated parcels limits the use of earth observation technologies to expensive high space resolution images. For the time being, farmers do not feel the need for an irrigation advisory service, manly because there is plenty of water which is not bought proportionally to its use. However, circumstances are changing rapidly and, relatively new for the region, environmental concerns related with irrigation, manly nitrate leaching by excess watering of crops prompts the need for an irrigation advisory service in order to maintain crop production with a more rational use of water. The DEMETER technology could be a

  20. Controllable steep dispersion with gain in a four-level N-scheme with four-wave mixing

    Science.gov (United States)

    Phillips, Nathaniel B.; Novikova, Irina; Mikhailov, Eugeniy E.; Budker, Dmitry; Rochester, Simon

    2013-01-01

    We present a theoretical analysis of the propagation of light pulses through a medium of four-level atoms, with two strong pump fields and a weak probe field in an N-scheme arrangement. We show that four-wave mixing has a profound effect on the probe-field group velocity and absorption, allowing the probe-field propagation to be tuned from superluminal to slow-light regimes with amplification.

  1. The sensitivity to the microphysical schemes on the skill of ...

    Indian Academy of Sciences (India)

    . The performance of the Goddard, Thompson, LIN and NSSL schemes are evaluated and compared with observations and a CONTROL forecast. This study is aimed to investigate the sensitivity to microphysics on the track and intensity with ...

  2. Simulation study on the efficiencies of MOET nucleus breeding schemes applying marker assisted selection in dairy cattle.

    Science.gov (United States)

    Luo, WeiZhen; Wang, YaChun; Zhang, Yuan

    2009-03-01

    Advantages of breeding schemes using genetic marker information and/or multiple ovulation and embryo transfer (MOET) technology over the traditional approach were extensively evaluated through simulation. Milk yield was the trait of interest and QTL was the genetic marker utilized. Eight dairy cattle breeding scenarios were considered, i.e., traditional progeny testing breeding scheme (denoted as STANPT), GASPT scheme including a pre-selection of young bulls entering progeny testing based on their own QTL information, MOETPT scheme using MOET technology to generate young bulls and a selection of young bulls limited within the full-sib family, GAMOPT scheme adopting both QTL pre-selection and MOET technology, COMBPT scheme using a mixed linear model which considered QTL genotype instead of the BLUP model in GAMOPT, and three non-progeny testing schemes, i.e. the MOET, GAMO and COMB schemes, corresponding to MOETPT, GAMOPT and COMBPT with progeny testing being part of the system. Animals were selected based on their breeding value which was estimated under an animal model framework. Sequential selection over 17 years was performed in the simulations and 30 replicates were designed for each scenario. The influences of using QTL information and MOET technology on favorable QTL allele frequency, true breeding values, polygenetic breeding values and the accumulated genetic superiority were extensively evaluated, for five different populations including active sires, lactating cows, bull dams, bull sires, and young bulls. The results showed that the combined schemes significantly outperformed other approaches wherein accumulated true breeding value progressed. The difference between schemes exclusively using QTL information or MOET technology was not significant. The STANPT scheme was the least efficient among the 8 schemes. The schemes using MOET technology had a higher polygenetic response than others in the 17th year. The increases of frequency of the favorable QTL

  3. A Study of Hadronic Calibration Schemes for Pion Test Beam Data in the ATLAS Forward Calorimeter

    CERN Document Server

    McCarthy, Thomas G

    The ATLAS forward calorimeters constitute a small though important fraction of the detector's calorimeter system, designed in part to accurately and precisely measure the energy of particles and jets of particles originating from the collisions of high-energy protons at the detector's centre. The application of hadronic weights, a practice common in high-energy calorimetry, provides a means of compensation for the fraction of energy which is deposited by particles in the detector, but which is invisible to the detector due to the nature of hadronic showers. Explored here are various schemes of extracting hadronic weights, as well as the application of such weights, based on pion data from the 2003 ATLAS forward calorimeter test beam. During the collection of test beam data, beams of both pions and electrons of known energy, ranging from 10 to 200 GeV, were fired at specific points of an isolated detector in order to understand its response. The improvement in noise-subtracted energy resolution with respect to...

  4. Additive operator-difference schemes splitting schemes

    CERN Document Server

    Vabishchevich, Petr N

    2013-01-01

    Applied mathematical modeling isconcerned with solving unsteady problems. This bookshows how toconstruct additive difference schemes to solve approximately unsteady multi-dimensional problems for PDEs. Two classes of schemes are highlighted: methods of splitting with respect to spatial variables (alternating direction methods) and schemes of splitting into physical processes. Also regionally additive schemes (domain decomposition methods)and unconditionally stable additive schemes of multi-component splitting are considered for evolutionary equations of first and second order as well as for sy

  5. a case control study

    African Journals Online (AJOL)

    Abrham

    2011-07-02

    Jul 2, 2011 ... with HIV/AIDS who developed active pulmonary tuberculosis and controls were people living with. HIV/AIDS without active tuberculosis. ... the infectious agent such as crowding and that impair the host immune system(1). ..... substance use such as cigarette smoking and alcohol consumption. In conclusion ...

  6. A Comparative Study of Mindfulness Efficiency Based on Islamic-Spiritual Schemes and Group Cognitive Behavioral Therapy on Reduction of Anxiety and Depression in Pregnant Women

    Directory of Open Access Journals (Sweden)

    Elahe Aslami

    2017-04-01

    Full Text Available Background: Anxiety and depression during the pregnancy period are among the factors affecting the pregnancy undesirable outcomes and delivery. One way of controlling anxiety and depression is mindfulness and cognitive behavioral therapy. The purpose of this study was to compare the efficiency of mindfulness based on the Islamic-spiritual schemas and group cognitive behavioral therapy on reduction of anxiety and depression in pregnant women. Methods: The research design was semi-experimental in the form of pretest-posttest using a control group. Among the pregnant women in the 16th to 32nd weeks of pregnancy who referred to the health center, 30 pregnant women with high anxiety level and 30 pregnant women with high depression participated in the research. Randomly 15 participants with high depression and 15 participants with high anxiety were considered in the intervention group under the treatment of mindfulness based on Islamic-spiritual schemes. In addition, 15 participants with high scores regarding depression and 15 with high scores in anxiety were considered in the other group. .The control group consisted of 15 pregnant women with high anxiety and depression. Beck anxiety-depression questionnaire was used in two steps of pre-test and post-test. Data were analyzed using SPSS, version 20, and P≤0.05 was considered as significant. Results: The results of multivariate analysis of variance test and tracking Tokey test showed that there was a significant difference between the mean scores of anxiety and depression in the two groups of mindfulness based on spiritual- Islamic scheme (P<0.001 and the group of cognitive behavioral therapy with each other (P<0.001 and with the control group(P<0.001. The mean of anxiety and depression scores decreased in the intervention group, but it increased in the control group. Conclusion: Both therapy methods were effective in reduction of anxiety and depression of pregnant women, but the effect of

  7. A Novel Type of Series Load Resonant High Frequency Soft Switching Inverter with Phase Shift Control Scheme

    Science.gov (United States)

    Kifune, Hiroyasu; Yamaguchi, Takumi; Hatanaka, Yoshihiro; Nakaoka, Mutsuo

    The voltage source full bridge series load resonant high frequency soft switching inverter using pulse phaseshift modulation (PSM) strategy is proposed, which can operate ZVS in the left hand side bridge leg and ZCS in the right side bridge leg. This inverter using IGBTs employs two passive components and does not need any additional auxiliary circuit for the active power switch to achieve soft switching commutation, and it has wide soft switching operation region from full power to 3% light power. Furthermore, constant frequency power regulation that is required for induction-heating power applications is introduced on the basis of PSM. In this paper, steady state switching modes of the inverter treated here and its power regulation scheme by PSM are described under a soft switching scheme. Because the proposed inverter can operate at series resonant frequency of series resonant circuit under soft switching condition, it is easy to design the value of series resonant capacitor. The design methods of loss-less snubbing circuit components for soft switching are described to reduce switching losses effectively. The feasible experiment of the proposed inverter is implemented to demonstrate the power regulation performance of proposed high frequency inverter, high efficiency 97.6% at full power condition is obtained.

  8. Small-scale classification schemes

    DEFF Research Database (Denmark)

    Hertzum, Morten

    2004-01-01

    Small-scale classification schemes are used extensively in the coordination of cooperative work. This study investigates the creation and use of a classification scheme for handling the system requirements during the redevelopment of a nation-wide information system. This requirements classificat....... This difference between the written requirements specification and the oral discussions at the meetings may help explain software engineers’ general preference for people, rather than documents, as their information sources.......Small-scale classification schemes are used extensively in the coordination of cooperative work. This study investigates the creation and use of a classification scheme for handling the system requirements during the redevelopment of a nation-wide information system. This requirements....... While coordination mechanisms focus on how classification schemes enable cooperation among people pursuing a common goal, boundary objects embrace the implicit consequences of classification schemes in situations involving conflicting goals. Moreover, the requirements specification focused on functional...

  9. New Ideas on Labeling Schemes

    DEFF Research Database (Denmark)

    Rotbart, Noy Galil

    times, effectively eliminating the second penalty mentioned. We continue this theoretical study in several ways. First, we dedicate a large part of the thesis to the graph family of trees, for which we provide an overview of labeling schemes supporting several important functions such as ancestry......, routing and especially adjacency. The survey is complemented by novel contributions to this study, among which are the first asymptotically optimal adjacency labeling scheme for bounded degree trees, improved bounds on ancestry labeling schemes, dynamic multifunctional labeling schemes and an experimental...

  10. IWHS Elevator Controller Study.

    Science.gov (United States)

    1978-11-24

    resetting, elapsed time meter. 5.7.3.5 The LDU design shall provide sufficient design margins to compensa te for norma l produc tion spread tolerances...AND INDLCAT ZNG ~~~ SW ITCHNOARDb P’OM ~.NIPS CONtROL . INDICA TING AND PROPULSION SYSTEMS FOR NORMA l , , EM E R G E N C Y AND C A S U A L T Y C O N...Progr eem ’ible Logic Array IA IA-by- P -b i t pregr.~ nlb Ie log ic arra y , 005. UP I 091 APA 3ecoder IN Three 1-of -I dec o ders , 15111 . lID • 292

  11. A comparative study of the energy certification schemes implemented in the UK and ASHRAE building energy labelling programme

    OpenAIRE

    Burman, E.; Mumovic, D.; Kimpian, J.

    2014-01-01

    Following inception of the Energy Performance of Buildings Directive (EPBD) in the EU, energy certification schemes have gained prominence in the UK in recent years. Introduction of building Energy Quotient (bEQ), ASHRAE’s new building energy labelling programme, provides an opportunity to compare these schemes and explore improvement opportunities. ASHRAE’s bEQ broadly follows the same principles that underpin the energy certification schemes implemented in the UK. However, greater consisten...

  12. Emergency control scheme reevaluation and proposal of a new project to prevent voltage collapse in the metropolitan system; Reevaluacion del esquema de control de emergencia y propuesta de um nuevo esquema para evitar colapso de tension en el sistema metropolitano

    Energy Technology Data Exchange (ETDEWEB)

    Escudero Scavone, Francisco [ANDE - Administracion Nacional de Electricidad, Asuncion (Paraguay)]. E-mail: OS_EE03@ande.gov.py

    2001-07-01

    This article presents emergence control schemes implemented in the subsystem 1 (SS1) which makes part of the ANDE system. These schemes seek to maintain the system in operation when simple contingencies take place in one among the five circuits which compose the main transmission trunk. The reasons for their implementation are linked to the end of the transmission capacity and problem of reactive losses which support the system voltage, therefore producing a general voltage drop which can take to the undesirable phenomenon of system voltage collapse. The scheme replies to the overloads in emergency regimen, through the necessary load disconnections to reestablish the balance between the load and reduced transmission capacity using an automatic, quick and efficient way.

  13. An approach for estimating measurement uncertainty in medical laboratories using data from long-term quality control and external quality assessment schemes.

    Science.gov (United States)

    Padoan, Andrea; Antonelli, Giorgia; Aita, Ada; Sciacovelli, Laura; Plebani, Mario

    2017-10-26

    The present study was prompted by the ISO 15189 requirements that medical laboratories should estimate measurement uncertainty (MU). The method used to estimate MU included the: a) identification of quantitative tests, b) classification of tests in relation to their clinical purpose, and c) identification of criteria to estimate the different MU components. Imprecision was estimated using long-term internal quality control (IQC) results of the year 2016, while external quality assessment schemes (EQAs) results obtained in the period 2015-2016 were used to estimate bias and bias uncertainty. A total of 263 measurement procedures (MPs) were analyzed. On the basis of test purpose, in 51 MPs imprecision only was used to estimate MU; in the remaining MPs, the bias component was not estimable for 22 MPs because EQAs results did not provide reliable statistics. For a total of 28 MPs, two or more MU values were calculated on the basis of analyte concentration levels. Overall, results showed that uncertainty of bias is a minor factor contributing to MU, the bias component being the most relevant contributor to all the studied sample matrices. The model chosen for MU estimation allowed us to derive a standardized approach for bias calculation, with respect to the fitness-for-purpose of test results. Measurement uncertainty estimation could readily be implemented in medical laboratories as a useful tool in monitoring the analytical quality of test results since they are calculated using a combination of both the long-term imprecision IQC results and bias, on the basis of EQAs results.

  14. Scheme Program Documentation Tools

    DEFF Research Database (Denmark)

    Nørmark, Kurt

    2004-01-01

    This paper describes and discusses two different Scheme documentation tools. The first is SchemeDoc, which is intended for documentation of the interfaces of Scheme libraries (APIs). The second is the Scheme Elucidator, which is for internal documentation of Scheme programs. Although the tools...

  15. Remarks on quantum duopoly schemes

    Science.gov (United States)

    Fraçkiewicz, Piotr

    2016-01-01

    The aim of this paper is to discuss in some detail the two different quantum schemes for duopoly problems. We investigate under what conditions one of the schemes is more reasonable than the other one. Using the Cournot's duopoly example, we show that the current quantum schemes require a slight refinement so that they output the classical game in a particular case. Then, we show how the amendment changes the way of studying the quantum games with respect to Nash equilibria. Finally, we define another scheme for the Cournot's duopoly in terms of quantum computation.

  16. Challenges of medicines management in the public and private sector under Ghana's National Health Insurance Scheme - A qualitative study.

    Science.gov (United States)

    Ashigbie, Paul G; Azameti, Devine; Wirtz, Veronika J

    2016-01-01

    Ghana established its National Health Insurance Scheme (NHIS) in 2003 with the goal of ensuring more equitable financing of health care to improve access to health services. This qualitative study examines the challenges and consequences of medicines management policies and practices under the NHIS as perceived by public and private service providers. This study was conducted in health facilities in the Eastern, Greater Accra and Volta regions of Ghana between July and August 2014. We interviewed 26 Key Informants (KIs) from a purposively selected sample of public and private sector providers (government and mission hospitals, private hospitals and private standalone pharmacies), pharmaceutical suppliers and NHIS district offices. Data was collected using semi-structured interview guides which covered facility accreditation, reimbursement practices, medicines selection, purchasing and pricing of medicines, and utilization of medicines. Codes for data analysis were developed based on the study questions and also in response to themes that emerged from the transcripts and notes. Most KIs agreed that the introduction of the NHIS has increased access to and utilization of medicines by removing cost barriers for patients; however, some pointed out the increased utilization could also be corollary to moral hazard. Common concerns across all facilities were the delays in receiving NHIS reimbursements, and low reimbursement rates for medicines which result in providers asking patients to pay supplementary fees. KIs reported important differences between private and public sectors including weak separation of prescribing and dispensing and limited use of drugs and therapeutic committees in the private sector, the disproportionate effects of unfavorable reimbursement prices for medicines, and inadequate participation of the private sector providers (especially pharmacies and licensed chemical sellers) in the NHIS. Health providers generally perceive the NHIS to have had a

  17. Comparative study of state-of-the-art myoelectric controllers for multigrasp prosthetic hands.

    Science.gov (United States)

    Segil, Jacob L; Controzzi, Marco; Weir, Richard F ff; Cipriani, Christian

    2014-01-01

    A myoelectric controller should provide an intuitive and effective human-machine interface that deciphers user intent in real-time and is robust enough to operate in daily life. Many myoelectric control architectures have been developed, including pattern recognition systems, finite state machines, and more recently, postural control schemes. Here, we present a comparative study of two types of finite state machines and a postural control scheme using both virtual and physical assessment procedures with seven nondisabled subjects. The Southampton Hand Assessment Procedure (SHAP) was used in order to compare the effectiveness of the controllers during activities of daily living using a multigrasp artificial hand. Also, a virtual hand posture matching task was used to compare the controllers when reproducing six target postures. The performance when using the postural control scheme was significantly better (p < 0.05) than the finite state machines during the physical assessment when comparing within-subject averages using the SHAP percent difference metric. The virtual assessment results described significantly greater completion rates (97% and 99%) for the finite state machines, but the movement time tended to be faster (2.7 s) for the postural control scheme. Our results substantiate that postural control schemes rival other state-of-the-art myoelectric controllers.

  18. CoCo trial: Color-coded blood pressure Control, a randomized controlled study

    OpenAIRE

    Chmiel C; Senn O; Rosemann T; Del Prete V; Steurer-Stey C

    2014-01-01

    Corinne Chmiel, Oliver Senn, Thomas Rosemann, Valerio Del Prete, Claudia Steurer-Stey Institute of General Practice and Health Services Research, University of Zurich, Zurich, Switzerland Background: Inadequate blood pressure (BP) control is a frequent challenge in general practice. The objective of this study was to determine whether a color-coded BP booklet using a traffic light scheme (red, >180 mmHg systolic BP and/or >110 mmHg diastolic BP; yellow, &g...

  19. Updated level scheme of 172Yb from 171Yb(nth, γ) reaction studied via gamma-gamma coincidence spectrometer

    Science.gov (United States)

    Nguyen, Ngoc Anh; Nguyen, Xuan Hai; Pham, Dinh Khang; Nguyen, Quang Hung; Ho, Huu Thang

    2017-08-01

    This paper provides the updated information on the level scheme of 172Yb nucleus studied via 171Yb(nth, γ) reaction using the gamma-gamma coincidence spectrometer at Dalat Nuclear Research Institute (Viet Nam). The latter is used because of its advantages in achieving the low Compton background as well as in identifying the correlated gamma transitions. We have detected in total the energies and intensities of 128 two-step gamma cascades corresponding to 79 primary transitions. By comparing the measured data with those extracted from the ENSDF library, 61 primary gamma transitions and corresponding energy levels together with 20 secondary gamma transitions are found to be the same as the ENSDF data. Beside that, 18 additional primary gamma transitions and corresponding energy levels plus 108 secondary ones are not found to currently exist in this library and they are therefore considered as the new data.

  20. Evaluation of urologic morbidity after radiotherapy for cervical carcinoma by urodynamic examinations and patient voiding schemes: a prospective study

    DEFF Research Database (Denmark)

    Lajer, Henrik; Thranov, Ingrid R; Bagi, Per

    2002-01-01

    To assess urologic morbidity in a 5-year period by urodynamic examinations and patient voiding schemes after radiotherapy and brachytherapy for cervical carcinoma.......To assess urologic morbidity in a 5-year period by urodynamic examinations and patient voiding schemes after radiotherapy and brachytherapy for cervical carcinoma....

  1. Hybrid advection scheme for 3-dimensional atmospheric models. Testing and application for a study of NO{sub x} transport

    Energy Technology Data Exchange (ETDEWEB)

    Zubov, V.A.; Rozanov, E.V. [Main Geophysical Observatory, St.Petersburg (Russian Federation); Schlesinger, M.E.; Andronova, N.G. [Illinois Univ., Urbana-Champaign, IL (United States). Dept. of Atmospheric Sciences

    1997-12-31

    The problems of ozone depletion, climate change and atmospheric pollution strongly depend on the processes of production, destruction and transport of chemical species. A hybrid transport scheme was developed, consisting of the semi-Lagrangian scheme for horizontal advection and the Prather scheme for vertical transport, which have been used for the Atmospheric Chemical Transport model to calculate the distributions of different chemical species. The performance of the new hybrid scheme has been evaluated in comparison with other transport schemes on the basis of specially designed tests. The seasonal cycle of the distribution of N{sub 2}O simulated by the model, as well as the dispersion of NO{sub x} exhausted from subsonic aircraft, are in a good agreement with published data. (author) 8 refs.

  2. Evaluation of selective control information detection scheme in orthogonal frequency division multiplexing-based radio-over-fiber and visible light communication links

    Science.gov (United States)

    Dalarmelina, Carlos A.; Adegbite, Saheed A.; Pereira, Esequiel da V.; Nunes, Reginaldo B.; Rocha, Helder R. O.; Segatto, Marcelo E. V.; Silva, Jair A. L.

    2017-05-01

    Block-level detection is required to decode what may be classified as selective control information (SCI) such as control format indicator in 4G-long-term evolution systems. Using optical orthogonal frequency division multiplexing over radio-over-fiber (RoF) links, we report the experimental evaluation of an SCI detection scheme based on a time-domain correlation (TDC) technique in comparison with the conventional maximum likelihood (ML) approach. When compared with the ML method, it is shown that the TDC method improves detection performance over both 20 and 40 km of standard single mode fiber (SSMF) links. We also report a performance analysis of the TDC scheme in noisy visible light communication channel models after propagation through 40 km of SSMF. Experimental and simulation results confirm that the TDC method is attractive for practical orthogonal frequency division multiplexing-based RoF and fiber-wireless systems. Unlike the ML method, another key benefit of the TDC is that it requires no channel estimation.

  3. NSGA-II based optimal control scheme of wind thermal power system for improvement of frequency regulation characteristics

    Directory of Open Access Journals (Sweden)

    S. Chaine

    2015-09-01

    Full Text Available This work presents a methodology to optimize the controller parameters of doubly fed induction generator modeled for frequency regulation in interconnected two-area wind power integrated thermal power system. The gains of integral controller of automatic generation control loop and the proportional and derivative controllers of doubly fed induction generator inertial control loop are optimized in a coordinated manner by employing the multi-objective non-dominated sorting genetic algorithm-II. To reduce the numbers of optimization parameters, a sensitivity analysis is done to determine that the above mentioned three controller parameters are the most sensitive among the rest others. Non-dominated sorting genetic algorithm-II has depicted better efficiency of optimization compared to the linear programming, genetic algorithm, particle swarm optimization, and cuckoo search algorithm. The performance of the designed optimal controller exhibits robust performance even with the variation in penetration levels of wind energy, disturbances, parameter and operating conditions in the system.

  4. Automatic lung nodule detection in thick slice CT: a comparative study of different gating schemes in CAD

    Science.gov (United States)

    Devarakota, Pandu; Dinesh, M. S.; Maduskar, Pragnya; Vikal, Siddharth; Raghupathi, Laks; Salganicoff, Marcos

    2011-03-01

    Common chest CT clinical workflows for detecting lung nodules use a large slice thickness protocol (typically 5 mm). However, most existing CAD studies are performed on a thin slice data (0.3-2 mm) available on state-of-the art scanners. A major challenge for the widespread clinical use of Lung CAD is the concurrent availability of both thick and thin resolutions for use by radiologist and CAD respectively. Having both slice thickness reconstructions is not always possible based on the availability of scanner technologies, acquisition parameters chosen at remote site, and transmission and archiving constraints that may make transmission and storage of large data impracticable. However, applying current thin-slice CAD algorithms on thick slice cases outside their designed acquisition parameters may result in degradation of sensitivity and high false-positive rate making them clinically unacceptable. Therefore a CAD system that can handle thicker slice acquisitions is desirable to address those situations. In this paper, we propose a CAD system which works directly on thick slice scans. We first propose a multi-stage classifier based CAD system for detecting lung nodules in such data. Furthermore, we propose different gating systems adapted for thick slice scans. The proposed gating schemes are based on: 1. wall-attached and non wall-attached. 2. central and non-central region. These gating schemes can be used independently or combined as well. Finally, we present prototype1 results showing significant improvement of CAD sensitivity at much better false positive rate on thick-slice CT images are presented.

  5. Design study on the efficiency of the thermal scheme of power unit of thermal power plants in hot climates

    Science.gov (United States)

    Sedlov, A.; Dorokhov, Y.; Rybakov, B.; Nenashev, A.

    2017-11-01

    At the stage of pre-proposals unit of the thermal power plants for regions with a hot climate requires a design study on the efficiency of possible options for the structure of the thermal circuit and a set of key parameters. In this paper, the thermal circuit of the condensing unit powerfully 350 MW. The main feature of the external conditions of thermal power plants in hot climates is the elevated temperature of cooling water of the turbine condensers. For example, in the Persian Gulf region as the cooling water is sea water. In the hot season of the year weighted average sea water temperature of 30.9 °C and during the cold season to 22.8 °C. From the turbine part of the steam is supplied to the distillation-desalination plant. In the hot season of the year heat scheme with pressure fresh pair of 23.54 MPa, temperature 570/560 °C and feed pump with electric drive (EDP) is characterized by a efficiency net of 0.25% higher than thermal schem with feed turbine pump (TDP). However, the supplied power unit with PED is less by 11.6 MW. Calculations of thermal schemes in all seasons of the year allowed us to determine the difference in the profit margin of units of the TDP and EDP. During the year the unit with the TDP provides the ability to obtain the profit margin by 1.55 million dollars more than the unit EDP. When using on the market subsidized price of electricity (Iran) marginal profit of a unit with TDP more at 7.25 million dollars.

  6. Numerical Study on Turbulent Airfoil Noise with High-Order Schemes

    DEFF Research Database (Denmark)

    Zhu, Wei Jun; Shen, Wen Zhong; Sørensen, Jens Nørkær

    2009-01-01

    step, the incompressible pressure and velocity form input to the acoustic equations. In this paper, sound generation from a NACA 0012 airfoil in turbulent flow condition is studied. The noise source regions are found at the trailing edge and the strength of the sources is depended on the Reynolds...

  7. Graphing calculator supported instrumentation schemes for the concept of derivative : a case study

    NARCIS (Netherlands)

    Roorda, G.; Vos, P.; Drijvers, Paul|info:eu-repo/dai/nl/074302922; Goedhart, M.

    2014-01-01

    This paper reports on the role of the graphing calculator (GC) in the learning of derivatives and instantaneous rate of change. In a longitudinal study, we administered task based interviews before and after the introduction of calculus. We analyzed students’ use of the GC in these interviews. This

  8. Graphing calculator supported instrumentation schemes for the concept of derivative: a case study

    NARCIS (Netherlands)

    Roorda, Gerrit; Vos, Pauline; Drijvers, P.H.M. (Paul); Goedhart, Maarten; Nicol, C.; Oesterle, S.; Liljedahl, P.; Allan, D.

    2014-01-01

    This paper reports on the role of the graphing calculator (GC) in the learning of derivatives and instantaneous rate of change. In a longitudinal study, we administered task based interviews before and after the introduction of calculus. We analyzed students’ use of the GC in these interviews. This

  9. Study on the Planar Undulator Scheme with Focusing Properties for PKU-FEL

    CERN Document Server

    Ding, Yuantao; Huang, Senlin; Wang, Yugang; Zhao, Kui; Zhuang, Jiejia

    2004-01-01

    An IR range SASE FEL test facility will be built at Peking University. The project is designed to get the SASE FEL at 7 micron driven by a superconducting accelerator. A hybrid planar Nd-Fe-B undulator is employed and the optimization of the external focus system for the undulator is studied. In the PKU-FEL facility, the electron energy is about 30-40 MeV. The combined function undulator with FODO lattice imposes quite stringent tolerances on the strength of the quads. To solve this problem, the weak natural focusing of the undulator in the vertical plane together with horizontally focusing quads, is proposed to supply the focusing in the facility. The combined function undulator of FOFO lattice and FF lattice in the horizontal plane are studied. Compared with the FODO lattice, the FOFO and FF lattice make the saturation a bit longer and the requirements of the field accuracy for the focusing system are much reduced.

  10. “Gestaltomics”: Systems Biology Schemes for the Study of Neuropsychiatric Diseases

    Directory of Open Access Journals (Sweden)

    Nora A. Gutierrez Najera

    2017-05-01

    Full Text Available The integration of different sources of biological information about what defines a behavioral phenotype is difficult to unify in an entity that reflects the arithmetic sum of its individual parts. In this sense, the challenge of Systems Biology for understanding the “psychiatric phenotype” is to provide an improved vision of the shape of the phenotype as it is visualized by “Gestalt” psychology, whose fundamental axiom is that the observed phenotype (behavior or mental disorder will be the result of the integrative composition of every part. Therefore, we propose the term “Gestaltomics” as a term from Systems Biology to integrate data coming from different sources of information (such as the genome, transcriptome, proteome, epigenome, metabolome, phenome, and microbiome. In addition to this biological complexity, the mind is integrated through multiple brain functions that receive and process complex information through channels and perception networks (i.e., sight, ear, smell, memory, and attention that in turn are programmed by genes and influenced by environmental processes (epigenetic. Today, the approach of medical research in human diseases is to isolate one disease for study; however, the presence of an additional disease (co-morbidity or more than one disease (multimorbidity adds complexity to the study of these conditions. This review will present the challenge of integrating psychiatric disorders at different levels of information (Gestaltomics. The implications of increasing the level of complexity, for example, studying the co-morbidity with another disease such as cancer, will also be discussed.

  11. Female Gender Scheme is Disturbed by Polycystic Ovary Syndrome: A Qualitative Study From Iran.

    Science.gov (United States)

    Nasiri Amiri, Fatemeh; Ramezani Tehrani, Fahimeh; Simbar, Masoumeh; Mohammadpour Thamtan, Reza Ali; Shiva, Niloofar

    2014-02-01

    Polycystic ovary syndrome (PCOS) is the most common endocrinopathy affecting up to one in every five women of reproductive age. The majority of researches on PCOS focus on its biomedical aspects, often overlooking and neglecting women's own perceptions and experiences. This study aimed to explore women's perception and experiences that influence their personal gender role. This research is a qualitative study by conventional content analysis. Semi-structured interviews were conducted with 23 reproductive aged women with PCOS, recruited from the reproductive endocrinology research center. , in-depth interviews were continued to reach data saturation. The study was carried out at the reproductive endocrinology research center of Shahid Beheshti University in Tehran All the interviews were recorded and transcribed, and qualitative content analysis of the data was conducted manually. Four themes were identified. Content analysis of the interviews revealed these women mainly perceived themselves with lack of physical attractiveness, loss of womanhood, interruption of sexual role and disruption of fertility potential, feelings were related to symptoms e.g. 'excess' hair; absent or disrupted menstrual cycle, obesity and infertility commonly experienced by women with PCOS. Women with PCOS are challenged in their perceptions of themselves as "feminine" because of their hairy appearance, irregular menses and lack of fertility and this influences their gender roles. Medical practitioners must understand how PCOS precisely affects women's roles and initiate management aimed at reconstructing their "womanhood", along with their medical treatment.

  12. A Control Scheme to Improve the Power Quality with the Absence of Dedicated Compensation Devices in Microgrid

    DEFF Research Database (Denmark)

    Naderipour, A.; Mohd Zin, A. A.; Habibuddin, M.H.

    2015-01-01

    devices, such as Active Power Filters (APFs). The proposed control method is composed of the Adjustable Synchronous Reference Frame (ASRF) and the Synchronous Reference Frame (SRF) methods. The ASRF and SRF are proposed to control the power injection and harmonic current compensation, respectively...

  13. A theoretical bilevel control scheme for power networks with large-scale penetration of distributed renewable resources

    DEFF Research Database (Denmark)

    Boroojeni, Kianoosh; Amini, M. Hadi; Nejadpak, Arash

    2016-01-01

    the residential demand and DRRs, we use the Gaussian white noise added to some periodic signals, formulated as a stochastic process. In the second level of the proposed control framework, we take the advantage of bulk generation units to improve the reliability by a global flow controller. In other words, we get...

  14. A Repetitive Control Scheme Aimed at Compensating the 6k + 1 Harmonics for a Three-Phase Hybrid Active Filter

    DEFF Research Database (Denmark)

    Luo, Zhaoxu; Su, Mei; Yang, Jian

    2016-01-01

    in stationary reference frame, which only compensates the 6k+1 harmonics (e.g. -5, +7, -11, +13) in three-phase systems and reduces the time delay to T0/6 . So compared with the earlier reduced delay time repetitive controllers, the robustness and transient performance is further improved, the waste of control...

  15. Nonlinear Correction Schemes for the Phase 1 LHC Insertion Region Upgrade and Dynamic Aperture Studies

    CERN Document Server

    de Maria, R; Tomás, R

    2009-01-01

    The Phase 1 LHC Interaction Region (IR) upgrade aims at increasing the machine luminosity essentially by reducing the beam size at the Interaction Point (IP). This requires a total redesign of the full IR. A large set of options has been proposed with conceptually different designs. This paper reports on a general approach for the compensation of the multipolar errors of the IR magnets in the design phase. The goal is to use the same correction approach for the different designs. The correction algorithm is based on the minimization of the differences between the IR transfer map with errors and the design IR transfer map. Its performance is tested using the dynamic aperture as figure of merit. The relation between map coefficients and resonance terms is also given as a way to target particular resonances by selecting the right map coefficients. The dynamic aperture is studied versus magnet aperture using recently established relations between magnetic errors and magnet aperture.

  16. An advanced current control compensation scheme to improve the microgrid power quality without using dedicated compensation devices

    DEFF Research Database (Denmark)

    Naderipour, A.; Zin, A. A.Mohd; Habibuddin, M. H.

    2016-01-01

    of the harmonics in Microgrid (MG) and between MG and Power Common Coupling (PCC). The current harmonics in the grid and MG are compensated without using dedicated compensation devices, such as active power filters (APFs), by the proposed current controller which is contain an advanced synchronous reference frame......For grid-connected inverters (GCI), switching harmonics can be effectively attenuated through some methods. This paper present an advanced current control method for GCI of distributed generators (DGs), which responsible for the DG to controlling the power injection to the grid and the cancellation...... (ASRF) controllers. The merged control methods are proposed for the interface inverter to perform the comprehensive activity of compensating for the harmonics, such as a correction of the system imbalance and the removal of the harmonics. The simulation results are presented to demonstrate the effective...

  17. Study of Intelligent Photovoltaic System Fault Diagnostic Scheme Based on Chaotic Signal Synchronization

    Directory of Open Access Journals (Sweden)

    Chin-Tsung Hsieh

    2013-01-01

    Full Text Available As the photovoltaic system consists of many equipment components, manual inspection will be very costly. This study proposes the photovoltaic system fault diagnosis based on chaotic signal synchronization. First, MATLAB was used to simulate the fault conditions of solar system, and the maximum power point tracking (MPPT was used to ensure the system's stable power and capture and record the system fault feature signals. The dynamic errors of various fault signals were extracted by chaotic signal synchronization, and the dynamic error data of various fault signals were recorded completely. In the photovoltaic system, the captured output voltage signal was used as the characteristic values for fault recognition, and the extension theory was used to create the joint domain and classical domain of various fault conditions according to the collected feature data. The matter-element model of extension engineering was constructed. Finally, the whole fault diagnosis system is only needed to capture the voltage signal of the solar photovoltaic system, so as to know the exact fault condition effectively and rapidly. The proposed fault diagnostor can be implemented by embedded system and be combined with ZigBee wireless network module in the future, thus reducing labor cost and building a complete portable renewable energy system fault diagnostor.

  18. A Systematic Approach for Dynamic Security Assessment and the Corresponding Preventive Control Scheme Based on Decision Trees

    DEFF Research Database (Denmark)

    Liu, Leo; Sun, Kai; Rather, Zakir Hussain

    2014-01-01

    This paper proposes a decision tree (DT)-based systematic approach for cooperative online power system dynamic security assessment (DSA) and preventive control. This approach adopts a new methodology that trains two contingency-oriented DTs on a daily basis by the databases generated from power...... system simulations. Fed with real-time wide-area measurements, one DT of measurable variables is employed for online DSA to identify potential security issues, and the other DT of controllable variables provides online decision support on preventive control strategies against those issues. A cost...

  19. A Study on an Energy Conservation and Interconnection Scheme between WSN and Internet Based on the 6LoWPAN

    Directory of Open Access Journals (Sweden)

    Runtong Zhang

    2015-01-01

    Full Text Available Wireless sensor network (WSN, which has broad application prospects, consists of small nodes with sensing, computation, and communications capabilities. IPv6 is used over low power WPAN (wireless personal area network which is run by 6LoWPAN technology on the LoWPAN devices. In order to establish seamless connection of two heterogeneous networks, that is, WSN and IPv6 network, this paper proposes an improved energy conservation and interconnection scheme (ECIS based on the analysis of the current schemes. Detailed design of each functional component in the new scheme is proposed, and an expansion of the SSCS module in NS2 802.15.4 simulator is examined. Comprehensive experiments on the simulation platform show that the newly proposed scheme is advantageous over existing results.

  20. Nested case-control studies.

    Science.gov (United States)

    Ernster, V L

    1994-09-01

    The nested case-control study design (or the case-control in a cohort study) is described here and compared with other designs, including the classic case-control and cohort studies and the case-cohort study. In the nested case-control study, cases of a disease that occur in a defined cohort are identified and, for each, a specified number of matched controls is selected from among those in the cohort who have not developed the disease by the time of disease occurrence in the case. For many research questions, the nested case-control design potentially offers impressive reductions in costs and efforts of data collection and analysis compared with the full cohort approach, with relatively minor loss in statistical efficiency. The nested case-control design is particularly advantageous for studies of biologic precursors of disease. To advance its prevention research agenda, NIH might be encouraged to maintain a registry of new and existing cohorts, with an inventory of data collected for each; to foster the development of specimen banks; and to serve as a clearinghouse for information about optimal storage conditions for various types of specimens.

  1. Thrust Removal Scheme for the FAST-MAC Circulation Control Model Tested in the National Transonic Facility

    Science.gov (United States)

    Chan, David T.; Milholen, William E., II; Jones, Gregory S.; Goodliff, Scott L.

    2014-01-01

    A second wind tunnel test of the FAST-MAC circulation control semi-span model was recently completed in the National Transonic Facility at the NASA Langley Research Center. The model allowed independent control of four circulation control plenums producing a high momentum jet from a blowing slot near the wing trailing edge that was directed over a 15% chord simple-hinged flap. The model was configured for transonic testing of the cruise configuration with 0deg flap deflection to determine the potential for drag reduction with the circulation control blowing. Encouraging results from analysis of wing surface pressures suggested that the circulation control blowing was effective in reducing the transonic drag on the configuration, however this could not be quantified until the thrust generated by the blowing slot was correctly removed from the force and moment balance data. This paper will present the thrust removal methodology used for the FAST-MAC circulation control model and describe the experimental measurements and techniques used to develop the methodology. A discussion on the impact to the force and moment data as a result of removing the thrust from the blowing slot will also be presented for the cruise configuration, where at some Mach and Reynolds number conditions, the thrust-removed corrected data showed that a drag reduction was realized as a consequence of the blowing.

  2. In Situ Test Study on Freezing Scheme of Freeze-Sealing Pipe Roof Applied to the Gongbei Tunnel in the Hong Kong-Zhuhai-Macau Bridge

    Directory of Open Access Journals (Sweden)

    Xiangdong Hu

    2016-12-01

    Full Text Available In order to solve the water sealing problem of soil between pipes of long distance curved pipe-jacked technology, Freeze-Sealing Pipe Roof (FSPR as an innovative pre-supporting method in tunnel engineering is being applied to the Gongbei Tunnel in the Hong Kong-Zhuhai-Macau Bridge. The definition of FSPR is that large diameter steel pipes are laid out in a circle around the cross section of tunnel in advance, then the artificial ground freezing method is adopted to freeze soil between steel pipes to form water-sealing curtain. An effective freeze control system, which contains master freezing tubes, enhancing freezing tubes and limiting freezing tubes, is established for building up the frozen soil curtain, maintaining its stability during excavation and controlling the volume of frozen soil to limit frost heave dynamically. An in-situ test was carried out to explore the optimal freezing scheme and control mode. The results of the test show that the principal freezing scheme of the solid pipe with hollow pipe as a complement is the most optimal scheme in active freezing phase of the real construction. Meanwhile, cold control mode is suggested to control frost heave in maintained freezing phase. The conclusions have important guiding significance for this kind of engineering construction.

  3. A Highly Robust Single-Loop Current Control Scheme for Grid-Connected Inverter with an Improved LCCL Filter Configuration

    DEFF Research Database (Denmark)

    Pan, Donghua; Ruan, Xinbo; Wang, Xiongfei

    2018-01-01

    . The weighted average current control, which splits the filter capacitor into two parts (in form of an LCCL filter) and commands the current flowing between these two parts, is independent of the resonance frequency, but on the other hand, it is limited by the poor sensitivity to the grid impedance variation...... and weak stability in the grid current. These limitations are comprehensively explained in this paper and then addressed by identifying that the single-loop weighted average current control is equivalent to the dual-loop grid current control with an inherent capacitor current active damping. By tuning...... the capacitor split proportion as a second degree of freedom, an optimal damping performance that is robust to the grid impedance variation can be naturally achieved using only the inherent damping. Thus, no extra damping is required, and the single-loop structure with only one current sensing turns...

  4. Numerical study of MHD supersonic flow control

    Science.gov (United States)

    Ryakhovskiy, A. I.; Schmidt, A. A.

    2017-11-01

    Supersonic MHD flow around a blunted body with a constant external magnetic field has been simulated for a number of geometries as well as a range of the flow parameters. Solvers based on Balbas-Tadmor MHD schemes and HLLC-Roe Godunov-type method have been developed within the OpenFOAM framework. The stability of the solution varies depending on the intensity of magnetic interaction The obtained solutions show the potential of MHD flow control and provide insights into for the development of the flow control system. The analysis of the results proves the applicability of numerical schemes, that are being used in the solvers. A number of ways to improve both the mathematical model of the process and the developed solvers are proposed.

  5. Control scheme of three-level H-bridge converter for interfacing between renewable energy resources and AC grid

    DEFF Research Database (Denmark)

    Pouresmaeil, Edris; Montesinos-Miracle, Daniel; Gomis-Bellmunt, Oriol

    2011-01-01

    This paper presents a control strategy of multilevel converters for integration of renewable energy resources into power grid. The proposed technique provides compensation for active, reactive, and harmonic current components of grid-connected loads. A three-level H-bridge converter is proposed a...

  6. Single conversion audio amplifier and DC-AC converters with high performance and low complexity control scheme

    DEFF Research Database (Denmark)

    Poulsen, Søren; Andersen, Michael Andreas E.

    2004-01-01

    This paper proposes a novel control topology for a mains isolated single conversion audio amplifier and DC-AC converters. The topology is made for use in audio applications, and differs from prior art in terms of significantly reduced distortion as well as lower system complexity. The topology can...

  7. Comprehensive Study of All-Solid-State Z-Scheme Photocatalytic Systems of ZnO/Pt/CdZnS

    KAUST Repository

    Isimjan, Tayirjan Taylor

    2017-08-22

    We have investigated a Z-scheme based on a ZnO/Pt/CdZnS photocatalyst, active in the presence of a complex medium composed of acetic acid and benzyl alcohol, the effects of which on the catalyst stability and performance are studied. Transmission electron microscopy images showed uniformly dispersed sub-nanometer Pt particles. Inductively coupled plasma and X-ray photoelectron spectroscopy analyses suggested that Pt is sandwiched between ZnO and CdZnS. An apparent quantum yield (AQY) of 34% was obtained over the [ZnO]4/1 wt %Pt/CdZnS system at 360 nm, 2.5-fold higher than that of 1%Pt/CdZnS (14%). Furthermore, an AQY of 16% was observed using [ZnO]4/1 wt %Pt/CdZnS, which was comparable to that of 1 wt %Pt/CdZnS (10%) at 460 nm. On the basis of these results, we proposed a charge transfer mechanism, which was confirmed through femtosecond transient absorption spectroscopy. Finally, we identified the two main factors that affected the stability of the catalyst, which were the sacrificial reagent and the acidic pH.

  8. Numerical study of silica-water based nanofluid nucleate pool boiling by two-phase Eulerian scheme

    Science.gov (United States)

    Salehi, H.; Hormozi, F.

    2017-10-01

    In this research, numerical simulation of nucleate pool boiling of water and water-silica nanofluid was investigated using Eulerian multiphase approach. At first, nucleate pool boiling of pure water was simulated. Classic heat flux partitioning (HFP) model was used for the prediction of bubble parameters. To validate proposed approach, numerical results were compared with experimental data. In the next step, this scheme has been used for water-silica nanofluid. Due to dilute nanofluid (0.1% volume) concentration, it was assumed as a homogenous liquid and therefore, a two-phase approach was applied to simulate its boiling. Meanwhile, various correlations were compared to determine nucleation site density and bubble departure frequency and the best equation was found. Results demonstrated nanoparticle deposition on the heater surface was a key factor that could change the heat transfer performance in boiling nanofluid. Therefore, accurate investigation of bubble behavior in nucleate boiling of nanofluids is a necessary concern to be focused in future modeling studies.

  9. A study of clinical assessment of frailty in patients on maintenance hemodialysis supported by cashless government scheme

    Directory of Open Access Journals (Sweden)

    Manjusha Yadla

    2017-01-01

    Full Text Available This is a prospective cohort study to assess the prevalence of frailty in patients undergoing maintenance hemodialysis (HD under the government-funded scheme at our center and to assess the relationship between frailty and falls, hospitalizations, and mortality. This was done at our center which is completely supported by the government, which provides HD to all the patients under poverty line. Epidemiological data, anthropometric measurements, comorbidities assessment, frailty assessment using Fried criteria, subsequent hospitalizations, falls, and mortality were recorded in our prevalent dialysis population at our center between October 2014 and October 2015. Two hundred and twenty-six patients were enrolled during this period. Twenty-one patients were excluded as they did not satisfy the inclusion criteria. Two hundred and five prospective patients were studied for the predictors of frailty. Frailty was present in 82% of the study population. Mean age of our study population was 44.95 ± 13.27 years. On univariate analysis, diabetes mellitus, hypertension (HTN, cerebrovascular accident (CVA, left ventricular dysfunction (LVD, peripheral vascular disease (PVD, smoking, hepatitis C, inadequate dialysis, intradialytic hypotension (IDH, interdialytic weight gain, low serum creatinine <4 mg/dL, and anemia (Hb <10 g/dL were found to be statistically significantly different between frail and nonfrail groups On multivariate regression analysis, only HTN, PVD, CVA, anemia, smoking, and IDH were found to be significant. Frailty is highly prevalent among dialysis population. Factors predicting frailty include HTN, smoking, LVD, PVD, CVA, smoking, anemia, and IDH. Frailty is a significant risk factor for falls and hospitalizations.

  10. Tip-tilt disturbance model identification for Kalman-based control scheme: application to XAO and ELT systems.

    Science.gov (United States)

    Meimon, Serge; Petit, Cyril; Fusco, Thierry; Kulcsar, Caroline

    2010-11-01

    Adaptive optics (AO) systems have to correct tip-tilt (TT) disturbances down to a fraction of the diffraction-limited spot. This becomes a key issue for very or extremely large telescopes affected by mechanical vibration peaks or wind shake effects. Linear quadratic Gaussian (LQG) control achieves optimal TT correction when provided with the temporal model of the disturbance. We propose a nonsupervised identification procedure that does not require any auxiliary system or loop opening and validate it on synthetic profile as well as on experimental data.

  11. A Study on the Enhancement of Positioning Accuracy Performance Using Interrogator Selection Schemes over Indoor Wireless Channels

    Science.gov (United States)

    Park, Seungkeun; Kang, Byeong Gwon

    In this paper, two kinds of interrogator selection schemes named as random interrogator selection and hybrid interrogator selection methods are considered to enhance the positioning accuracy under indoor wireless LAN environments and the performances are compared with those of the conventional methods called as normal and reference interrogator selection schemes. These interrogator selection schemes are based on received signal strength(RSS) levels and trilateration method. A testbed was set up to measure and compare the positioning estimation error of the considered methods and previous conventional ones. The experiments results showed that the accuracy of location estimation was enormously improved with the hybrid method as much as 3m especially in a hostile environment with some obstacles. Meanwhile, the differences of estimation errors are not so much (< 0.2m) without obstacle conditions among the four kinds of interrogator selection methods.

  12. Comparison of the Poisoning Severity Score and National Poison Data System schemes for the severity assessment of animal poisonings: a pilot study.

    Science.gov (United States)

    McFarland, Sarah E; Bronstein, Alvin C; Banerji, Shireen; LeBlond, Jane; Mischke, Reinhard H; Begemann, Kathrin; Desel, Herbert; Greiner, Matthias

    2017-08-01

    To date, there are no publicly available schemes designed and evaluated specifically for severity assessment of animal poisonings. This poses challenges for the evaluation and comparison of animal poisoning exposure data. Our objective for this pilot study was to evaluate agreement between raters using the Poisoning Severity Score (PSS) and National Poison Data System (NPDS) medical outcome scheme for severity assessment of canine exposures reported to a multistate poison center (PC) and to identify issues regarding their use for severity assessment of animal poisonings. Agreement between both schemes was also assessed. The first 196 canine exposures reported to a multistate PC between 1 January and 31 August 2016 were selected and initial inquiry data from exposures was scored by four independent raters. Interrater agreement and agreement between the severity systems was calculated using weighted kappa (Κ) (Light's kappa). Reported clinical effects were also described. Interrater agreement for both the PSS (Κ 0.31; 95% CI 0.19, 0.43) and NPDS schemes (Κ 0.34; 95% CI 0.22, 0.44) was low. Agreement between the schemes was slight (Κ 0.05; 95% CI -0.08, 0.16) for pooled results from all four raters. For the PSS, 71.7% (n = 281) of ratings were minor, 23.0% (n = 90) moderate, and 5.4% (n = 21) severe. For the NPDS, 69.6% (n = 273) of ratings were minor, 27.0% (n = 106) moderate, and 3.3% (n = 13) severe. The top three reported clinical effects included vomiting (n = 86, 29.9%) drowsiness/lethargy (n = 38, 13.2%), and diarrhea (n = 24, 8.3%). This study shows considerable variability between raters using either the PSS or NPDS schemes for canine exposures severity assessment. The subjective nature of the schemes, the influence of intra- and interrater variation, and predominance of minor cases on the study findings should be taken into account when interpreting this data. Further evaluation of these schemes is warranted and could

  13. A novel transient rotor current control scheme of a doubly-fed induction generator equipped with superconducting magnetic energy storage for voltage and frequency support

    Science.gov (United States)

    Shen, Yang-Wu; Ke, De-Ping; Sun, Yuan-Zhang; Daniel, Kirschen; Wang, Yi-Shen; Hu, Yuan-Chao

    2015-07-01

    A novel transient rotor current control scheme is proposed in this paper for a doubly-fed induction generator (DFIG) equipped with a superconducting magnetic energy storage (SMES) device to enhance its transient voltage and frequency support capacity during grid faults. The SMES connected to the DC-link capacitor of the DFIG is controlled to regulate the transient dc-link voltage so that the whole capacity of the grid side converter (GSC) is dedicated to injecting reactive power to the grid for the transient voltage support. However, the rotor-side converter (RSC) has different control tasks for different periods of the grid fault. Firstly, for Period I, the RSC injects the demagnetizing current to ensure the controllability of the rotor voltage. Then, since the dc stator flux degenerates rapidly in Period II, the required demagnetizing current is low in Period II and the RSC uses the spare capacity to additionally generate the reactive (priority) and active current so that the transient voltage capability is corroborated and the DFIG also positively responds to the system frequency dynamic at the earliest time. Finally, a small amount of demagnetizing current is provided after the fault clearance. Most of the RSC capacity is used to inject the active current to further support the frequency recovery of the system. Simulations are carried out on a simple power system with a wind farm. Comparisons with other commonly used control methods are performed to validate the proposed control method. Project supported by the National Natural Science Foundation of China (Grant No. 51307124) and the Major Program of the National Natural Science Foundation of China (Grant No. 51190105).

  14. Assessment of motivational interviewing: a qualitative study of response process validity, content validity and feasibility of the motivational interviewing target scheme (MITS) in general practice

    NARCIS (Netherlands)

    Oberink, Riëtta; Boom, Saskia M.; van Dijk, Nynke; Visser, Mechteld R. M.

    2017-01-01

    Background: The Motivational Interviewing target Scheme (MITS) is an instrument to assess competency in Motivational Interviewing (MI) and can be used to assess MI in long and brief consultations. In this qualitative study we examined two sources of the Unified Model of Validity, the current

  15. CP-ABE Access Control Scheme for Sensitive Data Set Constraint with Hidden Access Policy and Constraint Policy

    National Research Council Canada - National Science Library

    Nurmamat Helil; Kaysar Rahman

    2017-01-01

    .... However, a mechanism to prevent users from achieving successive access to a data owner’s certain number of data objects, which present a conflict of interest or whose combination thereof is sensitive, has yet to be studied...

  16. A design scheme of energy management,control,optimisation system for hybrid solar-wind and battery energy storages system

    OpenAIRE

    Sarban Singh, Ranjit Singh

    2016-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University London. Hybrid renewable energy system was introduced to improve the individual renewable energy power system’s productivity and operation-ability. This circumstance has led towards an extensive technological study and analysis on the hybrid renewable energy system. The extensive technological study is conducted using many different approaches, but in this research the linear programming, arti...

  17. A PWM Buck Converter With Load-Adaptive Power Transistor Scaling Scheme Using Analog-Digital Hybrid Control for High Energy Efficiency in Implantable Biomedical Systems.

    Science.gov (United States)

    Park, Sung-Yun; Cho, Jihyun; Lee, Kyuseok; Yoon, Euisik

    2015-12-01

    We report a pulse width modulation (PWM) buck converter that is able to achieve a power conversion efficiency (PCE) of > 80% in light loads 100 μA) for implantable biomedical systems. In order to achieve a high PCE for the given light loads, the buck converter adaptively reconfigures the size of power PMOS and NMOS transistors and their gate drivers in accordance with load currents, while operating at a fixed frequency of 1 MHz. The buck converter employs the analog-digital hybrid control scheme for coarse/fine adjustment of power transistors. The coarse digital control generates an approximate duty cycle necessary for driving a given load and selects an appropriate width of power transistors to minimize redundant power dissipation. The fine analog control provides the final tuning of the duty cycle to compensate for the error from the coarse digital control. The mode switching between the analog and digital controls is accomplished by a mode arbiter which estimates the average of duty cycles for the given load condition from limit cycle oscillations (LCO) induced by coarse adjustment. The fabricated buck converter achieved a peak efficiency of 86.3% at 1.4 mA and > 80% efficiency for a wide range of load conditions from 45 μA to 4.1 mA, while generating 1 V output from 2.5-3.3 V supply. The converter occupies 0.375 mm(2) in 0.18 μm CMOS processes and requires two external components: 1.2 μF capacitor and 6.8 μH inductor.

  18. Developing Assessment Policy and Evaluating Practice: A Case Study of the Introduction of A New Marking Scheme

    Science.gov (United States)

    Handley, Fiona J. L.; Read, Ann

    2017-01-01

    In 2011, Southampton Solent University, a post-1992 university in southern England, introduced a new marking scheme with the aims of changing marking practice to achieve greater transparency and consistency in marking, and to ensure that the full range of marks was being awarded to students. This paper discusses the strategic background to the…

  19. Optimizing School-Based Health-Promotion Programmes: Lessons from a Qualitative Study of Fluoridated Milk Schemes in the UK

    Science.gov (United States)

    Foster, Geraldine R. K.; Tickle, Martin

    2013-01-01

    Background and objective: Some districts in the United Kingdom (UK), where the level of child dental caries is high and water fluoridation has not been possible, implement school-based fluoridated milk (FM) schemes. However, process variables, such as consent to drink FM and loss of children as they mature, impede the effectiveness of these…

  20. Determinants of farmers’ willingness to participate in subsidy schemes for pesticide-free buffer zones - a choice experiment study

    DEFF Research Database (Denmark)

    Christensen, Tove; Pedersen, Anders Branth; Nielsen, Helle Oersted

    2011-01-01

    to participate in AES. While the trade off's that farmers are willing to make between subsidy size and individual scheme requirements are case specific, our results concerning increased use of farm advisors, farmers ability of valuing different types of flexibility, and our attempt to place a monetary value...

  1. Observer-based scheme for tuning the control of variable speed wind turbines operating in hostile environments

    DEFF Research Database (Denmark)

    Caruana, Cedric; Al-Durra, Ahmed; Blaabjerg, Frede

    2016-01-01

    The rapid growth rate of wind energy coupled with the increasing sizes of individual wind turbines strengthens the need for optimised wind energy capture. This study utilises the unknown input observer to track the variation of the maximal value of wind turbines' power coefficient to tune...

  2. [Comparative study of the conventional scheme and prolonged treatment with steroids on primary steroid-sensitive nephrotic syndrome in children].

    Science.gov (United States)

    Liern, Miguel; Codianni, Paola; Vallejo, Graciela

    In the steroid-sensitive nephrotic syndrome (SSNS) the prolonged treatment with steroids could decrease the frequency of relapses. We conducted a comparative study of prolonged steroid scheme and the usual treatment of primary SSNS to assess: the number of patients with relapses, mean time to treatment initiation, to remission and to first relapse, total number of relapses, total cumulative dose of steroids, and the steroid toxicity. Patients were divided into two groups: group A (27 patients) received 16-β-methylprednisolone for 12 weeks, reducing the steroid until week 24. Group B (29 patients) received 16-β-methylprednisolone for 12 weeks and placebo until week 24. Cumulative incidence rate of relapse (person/years) for group A was of 36/100 and 66/100 for group B (p=0.04). Average elapsed time to first relapse was of 114 days for group A and of 75 days to for group B (p=0.01). The difference in time for initial response to treatment and up to achieve remission between both groups was not significant. Total cumulative relapses were 9 for group A and 17 for group B (p=0.04). Total patients with relapses were 3 for group A and 7 for group B (p=0.17). Cumulative average dose per patient was 5,243mg/m2 for group A and 4,306mg/m2 for group B (p=0.3), and serum cortisol was 14μg/dl for group A and 16μg/dl for group B (p=0.4). There were no steroid toxicity differences between groups. The duration of the treatment had an impact on the number of relapses without increasing steroid toxicity. Copyright © 2016 Hospital Infantil de México Federico Gómez. Publicado por Masson Doyma México S.A. All rights reserved.

  3. Perry's Intellectual Scheme.

    Science.gov (United States)

    Love, Patrick G.; Guthrie, Victoria L.

    1999-01-01

    Summarizes William Perry's intellectual scheme and places it in the context of the 1990's. Perry's scheme of cognitive development, though more than thirty years old, is still being used by practitioners today to enhance practice in and out of the classroom. It laid a foundation for new research to extend, challenge, and build onto the scheme.…

  4. Finite Boltzmann schemes

    NARCIS (Netherlands)

    Sman, van der R.G.M.

    2006-01-01

    In the special case of relaxation parameter = 1 lattice Boltzmann schemes for (convection) diffusion and fluid flow are equivalent to finite difference/volume (FD) schemes, and are thus coined finite Boltzmann (FB) schemes. We show that the equivalence is inherent to the homology of the

  5. Experimental Validation of a Compound Control Scheme for a Two-Axis Inertially Stabilized Platform with Multi-Sensors in an Unmanned Helicopter-Based Airborne Power Line Inspection System.

    Science.gov (United States)

    Zhou, Xiangyang; Jia, Yuan; Zhao, Qiang; Yu, Ruixia

    2016-03-11

    A compound control scheme is proposed to achieve high control performance for a two-axis inertially stabilized platform (ISP) with multi-sensors applied to an unmanned helicopter (UH)-based airborne power line inspection (APLI) system. Compared with the traditional two closed-loop control scheme that is composed of a high-bandwidth rate loop and a lower bandwidth position loop, a new current loop inside rate loop is particularly designed to suppress the influences of voltage fluctuation from power supply and motor back electromotive force (BEMF) on control precision. In this way, the stabilization accuracy of the ISP is greatly improved. The rate loop, which is the middle one, is used to improve sensor's stability precision through compensating for various disturbances. To ensure the pointing accuracy of the line of sight (LOS) of multi-sensors, the position loop is designed to be the outer one and acts as the main feedback path, by which the accurate pointing angular position is achieved. To validate the scheme, a series of experiments were carried out. The results show that the proposed compound control scheme can achieve reliable control precision and satisfy the requirements of real APLI tasks.

  6. Experimental Validation of a Compound Control Scheme for a Two-Axis Inertially Stabilized Platform with Multi-Sensors in an Unmanned Helicopter-Based Airborne Power Line Inspection System

    Directory of Open Access Journals (Sweden)

    Xiangyang Zhou

    2016-03-01

    Full Text Available A compound control scheme is proposed to achieve high control performance for a two-axis inertially stabilized platform (ISP with multi-sensors applied to an unmanned helicopter (UH-based airborne power line inspection (APLI system. Compared with the traditional two closed-loop control scheme that is composed of a high-bandwidth rate loop and a lower bandwidth position loop, a new current loop inside rate loop is particularly designed to suppress the influences of voltage fluctuation from power supply and motor back electromotive force (BEMF on control precision. In this way, the stabilization accuracy of the ISP is greatly improved. The rate loop, which is the middle one, is used to improve sensor’s stability precision through compensating for various disturbances. To ensure the pointing accuracy of the line of sight (LOS of multi-sensors, the position loop is designed to be the outer one and acts as the main feedback path, by which the accurate pointing angular position is achieved. To validate the scheme, a series of experiments were carried out. The results show that the proposed compound control scheme can achieve reliable control precision and satisfy the requirements of real APLI tasks.

  7. Impact of startup scheme on Francis runner life expectancy

    Energy Technology Data Exchange (ETDEWEB)

    Gagnon, M; Tahan, S A; Bocher, P [Department of Mechanical Engineering, Ecole de technologie superieure (ETS) 1100, rue Notre-Dame Ouest, Montreal (Canada); Thibault, D, E-mail: martin.gagnon.8@ens.etsmtl.c [Institut de recherche d' Hydro-Quebec (IREQ), 1800, boul. Lionel-Boulet, Varennes, J3X 1S1 (Canada)

    2010-08-15

    Francis runners are subject to complex dynamic forces which might lead to eventual blade cracking and the need for corrective measure. Damage due to cracks in runner blades are usually not a safety issues but might generate unexpected down time and high repair cost. Avoiding the main damaging operating conditions is often the only option left to plant operators to maximize the life expectancy of their runner. The startup scheme is one of the available parameter which is controlled by the end user and could be used to minimize the damage induced to the runner. In this study, two startup schemes have been used to investigate life expectancy of Francis runner using in situ measurements. The results obtained show that the induced damage during the startup event could be significantly reduced with change to the startup scheme. In our opinion, an optimization of the startup scheme with regard to fatigue damage could extend significantly the life expectancy and the reliability of Francis runner.

  8. Studies and Proposals for an Automatic Crystal Control System

    CERN Document Server

    Drobychev, Gleb; Khruschinsky, A A; Korzhik, Mikhail; Missevitch, Oleg; Oriboni, André; Peigneux, Jean-Pierre; Schneegans, Marc

    1997-01-01

    This document presents the status of the studies for an Automatic Crystal Control System ( ACCOS) performed since autumn 1995 for the CMS collaboration. Evaluation of a startstop method for light yield, light uniformity and decay time measurements of PbWO4 crystals is presented, as well as the first results obtained with a compact double-beam spectrophotometer for transverse transmission. Various overall schemes are proposed for an integrated set-up including crystal dimension measurement. The initial financial evaluationperformed is also given.

  9. Precise control of a four degree-of-freedom permanent magnet biased active magnetic bearing system in a magnetically suspended direct-driven spindle using neural network inverse scheme

    Science.gov (United States)

    Sun, Xiaodong; Su, Bokai; Chen, Long; Yang, Zebin; Xu, Xing; Shi, Zhou

    2017-05-01

    The capacity of improving the control accuracy and dynamic performance of a four degree-of-freedom (DOF) permanent magnet biased active magnetic bearing (PMBAMB) system is critical to developing and maintaining a high precision application in a magnetically suspended direct-driven spindle system. The 4-DOF PMBAMB system, however, is a multivariable, strong coupled and nonlinear system with unavoidable and unmeasured external disturbances, in addition to having parameter variations. The satisfactory control performance cannot be obtained by using traditional strategies. Therefore, it is important to present a novel control scheme to construct a robust controller with good closed-loop capability. This paper proposes a new decoupling control scheme for a 4-DOF PMBAMB in a direct-driven spindle system based on the neural network inverse (NNI) and 2- degree-of-freedom (DOF) internal model control method. By combining the inversion of the 4-DOF PMBAMB system with its original system, a new pseudolinear system can be developed. In addition, by introducing the 2-DOF internal model controller into the pseudolinear system to design extra closed-loop controllers, we can effectively eliminate the influence of the unmodeled dynamics to the decoupling control accuracy, as well as adjust the properties of tracking and disturbance rejection independently. The experimental results demonstrate the effectiveness of the proposed control scheme.

  10. Lessons learnt during the process of setup and implementation of the voucher scheme in Eastern Uganda: a mixed methods study.

    Science.gov (United States)

    Bua, John; Paina, Ligia; Kiracho, Elizabeth Ekirapa

    2015-08-06

    In spite of the investments made by the Ugandan Government, the utilisation of maternal health services has remained low, resulting in a high maternal mortality (438 maternal deaths per 100,000 live births). Aiming to reduce poor women's constraints to the utilisation of services, an intervention consisting of a voucher scheme and health system strengthening was implemented. This paper presents the lessons learnt during the setup and implementation of the intervention in Eastern Uganda, in order to inform the design and scale up of similar future interventions. The key lessons were synthesised from a variety of project reports, as well as qualitative data drawn from six focus group discussions and four in-depth interviews conducted in the Buyende and Pallisa districts during the implementation phase of the voucher scheme. To promote the successful implementation of interventions with demand and supply side initiatives, such as voucher schemes, the health system should be able to respond to the demand created by providing the additional required resources such as health workers, essential supplies and equipment. Involving a diverse, multi-sectoral group of stakeholders is important for addressing the different barriers experienced by women when seeking maternal health services. Voucher schemes should have a mechanism of detecting unintended consequences and mitigating them. Sustainability plans should be built into such interventions to maintain the gains achieved. Lastly, health policy planners can use this information to develop follow-up programmes to test modified versions that are more sustainable. Such programmes could use locally existing community structures for management and resource mobilisation for self-sustainment.

  11. Which missing value imputation method to use in expression profiles: a comparative study and two selection schemes

    Directory of Open Access Journals (Sweden)

    Lotz Meredith J

    2008-01-01

    Full Text Available Abstract Background Gene expression data frequently contain missing values, however, most down-stream analyses for microarray experiments require complete data. In the literature many methods have been proposed to estimate missing values via information of the correlation patterns within the gene expression matrix. Each method has its own advantages, but the specific conditions for which each method is preferred remains largely unclear. In this report we describe an extensive evaluation of eight current imputation methods on multiple types of microarray experiments, including time series, multiple exposures, and multiple exposures × time series data. We then introduce two complementary selection schemes for determining the most appropriate imputation method for any given data set. Results We found that the optimal imputation algorithms (LSA, LLS, and BPCA are all highly competitive with each other, and that no method is uniformly superior in all the data sets we examined. The success of each method can also depend on the underlying "complexity" of the expression data, where we take complexity to indicate the difficulty in mapping the gene expression matrix to a lower-dimensional subspace. We developed an entropy measure to quantify the complexity of expression matrixes and found that, by incorporating this information, the entropy-based selection (EBS scheme is useful for selecting an appropriate imputation algorithm. We further propose a simulation-based self-training selection (STS scheme. This technique has been used previously for microarray data imputation, but for different purposes. The scheme selects the optimal or near-optimal method with high accuracy but at an increased computational cost. Conclusion Our findings provide insight into the problem of which imputation method is optimal for a given data set. Three top-performing methods (LSA, LLS and BPCA are competitive with each other. Global-based imputation methods (PLS, SVD, BPCA

  12. Alternative fabrication scheme to study effects of rework of nonconforming products and delayed differentiation on a multiproduct supply-chain system

    Directory of Open Access Journals (Sweden)

    Yuan-Shyi Peter Chiu

    2017-07-01

    Full Text Available This study uses an alternative fabrication scheme to study the effect of rework of nonconforming items and delayed differentiation on a multiproduct supply-chain system. Traditional economic production quantity model focuses on a single-product inventory system where all products made are assumed to be perfect quality and finished products are issued continuously. To increase machine utilization, lower quality costs in production, and reflect the real-world vendor-buyer integrated systems Chiu et al. (2016a [Chiu, Y-S.P., Kuo, J-S., Chiu, S. W., Hsieh, Y-T. (2016a. Effect of delayed differentiation on a multiproduct vendor–buyer integrated inventory system with rework. Advances in Production Engineering & Management, 11(4, 333-344.] employed a single-machine two-stage production scheme to study the effects of rework and delayed differentiation on a multi-product supply-chain system. With the intention of further reducing fabrication cycle time, this study considers an alternative two-machine two-stage fabrication scheme to re-explore the problem in Chiu et al. (2016a. Machine one solely produces all common parts for multiple end products. Then, machine two fabricates the customized multiproduct using a common cycle time strategy. Through the use of mathematical modeling and analyses, the optimal production cycle length and distribution policy are derived. Numerical examples are provided to demonstrate practical usage of the research results, and show its significant benefit in reducing fabrication cycle time compared to that obtained from prior studies that used different schemes.

  13. An Approximate Optimal Maximum Range Guidance Scheme for Subsonic Unpowered Gliding Vehicles

    Directory of Open Access Journals (Sweden)

    Dao-Chi Zhang

    2015-01-01

    Full Text Available This study investigates the maximum gliding range problems of subsonic unpowered gliding vehicles and proposes an approximate optimal maximum range guidance scheme. First, the gliding flight path angle corresponding to constant dynamic pressure is derived. A lift-to-drag ratio (L/D inversely proportional to the dynamic pressure is then proven. On this basis, the calculation method of an optimal dynamic pressure (ODP profile with a maximum L/D throughout the flight is presented. A guidance scheme for tracking the ODP profile, which uses the flight path angle as control variable, is then designed. The maximum ranges of the unpowered gliding vehicle obtained by the proposed guidance scheme and pseudospectral method are compared. Results show that the guidance scheme provides an accurate approximation of the optimal results, and the errors are less than 2%. The proposed guidance scheme is easy to implement and is not influenced by wind compared with numerical schemes.

  14. An evaluation of the effectiveness and cost effectiveness of the National Exercise Referral Scheme in Wales, UK: a randomised controlled trial of a public health policy initiative.

    Science.gov (United States)

    Murphy, Simon Mark; Edwards, Rhiannon Tudor; Williams, Nefyn; Raisanen, Larry; Moore, Graham; Linck, Pat; Hounsome, Natalia; Din, Nafees Ud; Moore, Laurence

    2012-08-01

    The Wales National Exercise Referral Scheme (NERS) is a 16-week programme including motivational interviewing, goal setting and relapse prevention. A pragmatic randomised controlled trial with nested economic evaluation of 2160 inactive participants with coronary heart disease risk (CHD, 1559, 72%), mild to moderate depression, anxiety or stress (79, 4%) or both (522, 24%) randomised to receive (1) NERS or (2) normal care and brief written information. Outcome measures at 12 months included the 7-day physical activity recall, the hospital anxiety and depression scale. Ordinal regression identified increased physical activity among those randomised to NERS compared with those receiving normal care in all participants (OR 1.19, 95% CI 0.99 to 1.43), and among those referred for CHD only (OR 1.29, 95% CI 1.04 to 1.60). For those referred for mental health reason alone, or in combination with CHD, there were significantly lower levels of anxiety (-1.56, [corrected] 95% CI -2.75 to -0.38) and depression (-1.39, [corrected] 95% CI -2.60 to -0.18), but no effect on physical activity. The base-case incremental cost-effectiveness ratio was £12,111 per quality adjusted life year, falling to £9741 if participants were to contribute £2 per session. NERS was effective in increasing physical activity among those referred for CHD risk only. Among mental health referrals, NERS did not influence physical activity but was associated with reduced anxiety and depression. Effects were dependent on adherence. NERS is likely to be cost effective with respect to prevailing payer thresholds. Trial registration Current Controlled Trials ISRCTN47680448.

  15. a randomized, placebo- controlled study

    OpenAIRE

    Hall, Franziska van

    2012-01-01

    Introduction: Repetitive transcranial magnetic stimulation (rTMS) is a well-tolerated non-invasive method, which has also been proved to have mild antidepressant effects and is used as “add-on“-therapy in treating pharmaco-resistant major depression. Objective: The efficacy of an escitalopram plus rTMS-combination-treatment was evaluated and compared to escitalopram plus sham rTMS. Methods: We designed a four week-, randomized, rater-blinded, and controlled add-on study with two trea...

  16. The Mawala irrigation scheme

    OpenAIRE

    de Bont, Chris

    2018-01-01

    This booklet was written to share research results with farmers and practitioners in Tanzania. It gives a summary of the empirical material collected during three months of field work in the Mawala irrigation scheme (Kilimanjaro Region), and includes maps, tables and photos. It describes the history of the irrigation scheme, as well current irrigation and farming practices. It especially focuses on the different kinds of infrastructural improvement in the scheme (by farmers and the government...

  17. A Study of Flow Separation in Transonic Flow Using Inviscid and Viscous Computational Fluid Dynamics (CFD) Schemes

    Science.gov (United States)

    Rhodes, J. A.; Tiwari, S. N.; Vonlavante, E.

    1988-01-01

    A comparison of flow separation in transonic flows is made using various computational schemes which solve the Euler and the Navier-Stokes equations of fluid mechanics. The flows examined are computed using several simple two-dimensional configurations including a backward facing step and a bump in a channel. Comparison of the results obtained using shock fitting and flux vector splitting methods are presented and the results obtained using the Euler codes are compared to results on the same configurations using a code which solves the Navier-Stokes equations.

  18. Awareness and utilization of social security scheme and other government benefits by the elderly – A study in rural area of district Dehradun

    Directory of Open Access Journals (Sweden)

    Ashok Kumar Srivastava

    2014-12-01

    Full Text Available Background: The rapid ageing of India’s population, has highlighted the need for better economic security arrangements for the elderly. Increased longevity is making care of the elderly more expensive and traditional family ties are beginning to fray, and The Government of India have initiated an array of schemes and benefits for providing some level of social security to the elderly. Objectives:  To study the background characteristic of the elderly and extent of awareness and utilization of social security and other government benefits. Methodology: Study Design: Descriptive, observational cross sectional field based study. Statistical analysis: Percentages and proportions. Results: Three out of every five houses was headed by an elderly. No formal education was received by 35.4% of the elderly. Widowhood was as high as 49.5% among elderly women. Awareness of social security scheme (Indira Gandhi National Old Age Pension Scheme was observed in 74.6% of the elderly but only 45.4% utilized it. The proportion of elderly who were aware of concession in railway ticket and higher interest rates on deposits in Bank/Post office respectively was 34.9% and 32.9%. The utilization rate was however abysmally low with 27.8% utilizing railway ticket concession and 10.1% depositing money to get higher interest in Bank/Post office. Less than 1% elderly utilized income tax benefits. Conclusion: There is an urgent need to review the existing policy guidelines and amend them to suit and benefit the elderly. The schemes and benefits meant for the elderly needs to be more relevant and effectively implemented at the community level.

  19. Experimental Study on Active Control of Surge in a Centrifugal Compression System

    Directory of Open Access Journals (Sweden)

    Nie Chaoqun

    2000-01-01

    Full Text Available An experimental study has been carried out on the active control of surge in a centrifugal compression system. With a computerized on-line control scheme, the surge phenomenon is suppressed and the stable operating range of the system is extended. In order to design the active control scheme and choose the desired parameters of the control system inputs, special emphases have been placed on the development of surge inception and the nonlinear interaction between the system and the actuator. By use of the method designed in the present work, the results of active control onsurge have been demonstrated for the different B parameters, different prescribed criteria and different control frequencies.

  20. Retrofitting of the small hydro electric scheme 'Moulin de Bavois' - Feasibility study; Rehabilitation du Moulin de Bavois. Etude d'avant-projet

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-15

    This illustrated final report for the Swiss Federal Office of Energy (SFOE) is a feasibility study of the retrofitting of the small hydro electric scheme 'Moulin de Bavois' located in Bavois on the Talent river, Switzerland. The existing scheme uses a 12 m water fall and its power amounts to about 10 kW. After retrofitting, based on a future new water-use concession, the maximum electric power produced should be 172 kW, generating 531 MWh/y, 65% of which in the wintertime. New weir and penstock are foreseen as is an axial Kaplan turbine and a reliable water cleaning device. The Talent river flows in the woods. Electricity production cost is estimated to be 0.214 CHF/kWh.

  1. Feasibility Studies on the Use of Higher Frequency Bands and Beamforming Selection Scheme for High Speed Train Communication

    Directory of Open Access Journals (Sweden)

    Ayotunde O. Laiyemo

    2017-01-01

    Full Text Available With increasing popularity of high speed trains and traffic forecast for future cellular networks, the need to provide improved data rates using higher frequency bands (HFBs for train passengers is becoming crucial. In this paper, we modify the OFDM frame structure for HST, taking into account the increasing sensitivity to speed at HFBs. A lower bound on the SNR/SINR for a given rate for reliable communication was derived considering the physical layer parameters from the OFDM frame. We also analyze different pathloss models in the context of examining the required gain needed to achieve the same performance as with microwave bands. Finally, we present a time-based analogue beamforming selection approach for HST. We observed that, irrespective of the pathloss models used, the required gains are within the same range. For the same SNR/SINR at different frequency bands, the achievable data rate varies with respect to the frequency bands. Our results show the potential of the use of HFBs. However, due to the increased sensitivity of some channel parameters, a maximum frequency band of 38 GHz is suggested. Evaluation of our proposed beamforming scheme indicates a close performance to the optimal SVD scheme with a marginal rate gap of less than 2 b/s/Hz.

  2. REFERQUAL: a pilot study of a new service quality assessment instrument in the GP exercise referral scheme setting

    Science.gov (United States)

    Cock, Don; Adams, Iain C; Ibbetson, Adrian B; Baugh, Phil

    2006-01-01

    Background The development of an instrument accurately assessing service quality in the GP Exercise Referral Scheme (ERS) industry could potentially inform scheme organisers of the factors that affect adherence rates leading to the implementation of strategic interventions aimed at reducing client drop-out. Methods A modified version of the SERVQUAL instrument was designed for use in the ERS setting and subsequently piloted amongst 27 ERS clients. Results Test re-test correlations were calculated via Pearson's 'r' or Spearman's 'rho', depending on whether the variables were Normally Distributed, to show a significant (mean r = 0.957, SD = 0.02, p < 0.05; mean rho = 0.934, SD = 0.03, p < 0.05) relationship between all items within the questionnaire. In addition, satisfactory internal consistency was demonstrated via Cronbach's 'α'. Furthermore, clients responded favourably towards the usability, wording and applicability of the instrument's items. Conclusion REFERQUAL is considered to represent promise as a suitable tool for future evaluation of service quality within the ERS community. Future research should further assess the validity and reliability of this instrument through the use of a confirmatory factor analysis to scrutinise the proposed dimensional structure. PMID:16725021

  3. Development of a Model for a Cordon Pricing Scheme Considering Environmental Equity: A Case Study of Tehran

    Directory of Open Access Journals (Sweden)

    Shahriar Afandizadeh

    2016-02-01

    Full Text Available Congestion pricing strategy has been recognized as an effective countermeasure in the practical field of urban traffic congestion mitigation. Despite the positive effects of congestion pricing, its implementation has faced problems. This paper investigates the issue of environmental equity in cordon pricing and a park-and-ride scheme. Although pollution decreases inside the cordon by implementation of cordon pricing, air pollutants emission may increase in some links and in the whole network. Therefore, an increase in air emissions in the network means more emission outside the cordon. In fact, due to the implementation of this policy, air pollutants emission may transfer from inside to outside the cordon, creating a type of environmental inequity. To reduce this inequity, a bi-level optimization model with an equity constraint is developed. The proposed solution algorithm based on the second version of the strength Pareto evolutionary algorithm (SPEA2 is applied to the city network in Tehran. The results revealed that it seems reasonable to consider environmental equity as an objective function in cordon pricing. In addition, we can create a sustainable situation for the transportation system by improving environmental inequity with a relatively low reduction in social welfare. Moreover, there are environmental inequity impacts in real networks, which should be considered in the cordon pricing scheme.

  4. Study of Streptococcus thermophilus population on a world-wide and historical collection by a new MLST scheme.

    Science.gov (United States)

    Delorme, Christine; Legravet, Nicolas; Jamet, Emmanuel; Hoarau, Caroline; Alexandre, Bolotin; El-Sharoud, Walid M; Darwish, Mohamed S; Renault, Pierre

    2017-02-02

    We analyzed 178 Streptococcus thermophilus strains isolated from diverse products, from around the world, over a 60-year period with a new multilocus sequence typing (MLST) scheme. This collection included isolates from two traditional cheese-making sites with different starter-use practices, in sampling campaigns carried out over a three years period. The nucleotide diversity of the S. thermophilus population was limited, but 116 sequence types (ST) were identified. Phylogenetic analysis of the concatenated sequences of the six housekeeping genes revealed the existence of groups confirmed by eBURST analysis. Deeper analyses performed on 25 strains by CRISPR and whole-genome analysis showed that phylogenies obtained by MLST and whole-genome analysis were in agreement but differed from that inferred by CRISPR analysis. Strains isolated from traditional products could cluster in specific groups indicating their origin, but also be mixed in groups containing industrial starter strains. In the traditional cheese-making sites, we found that S. thermophilus persisted on dairy equipment, but that occasionally added starter strains may become dominant. It underlined the impact of starter use that may reshape S. thermophilus populations including in traditional products. This new MLST scheme thus provides a framework for analyses of S. thermophilus populations and the management of its biodiversity. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. NATURAL RESOURCE MANAGEMENT IN THE SIERRA OF SONORA UNDER THE SCHEME UMAFOR. CASE STUDY: SIERRA ALTA AND SIERRA LA MADERA

    Directory of Open Access Journals (Sweden)

    Hugo Silva-Kurumiya

    2011-05-01

    Full Text Available This paper shows the use and value of natural resources from a social, sustainable and legal perspective, under the scheme of Sustainable Forest Management Units (UMAFOR by its Spanish acronym. Two participatory workshops were carried out in March 2010, one in UMAFOR Sierra La Madera and another in UMAFOR Sierra Alta, belonging to the Sierra de Sonora. An adaptation of “Problems, Causes and Consequences” of Ramírez-García (2004 methodology was used to discuss issues such as conservation, productive activities, society, laws, research and support programs. The objective was to analyze challenges and opportunities in the Sierra de Sonora under this management scheme. The ratting of natural resource for inhabitant and producers was documented based in ecosystems type and its value for use. Economic value was the most important for productive and non productive use; however, there are opportunities to transit from traditional to sustainable activities. Local producers are interested in linking whit research centers and consultants to get support for diversification of productive activities. It is possible to have changes according to sustainable development; UMAFOR is an alternative to achieve those changes.

  6. Robust synchronization control scheme of a population of nonlinear stochastic synthetic genetic oscillators under intrinsic and extrinsic molecular noise via quorum sensing

    Science.gov (United States)

    2012-01-01

    the help of LMI toolbox in MATLAB easily. Conclusion If the synchronization robustness criterion, i.e. the synchronization robustness ≥ intrinsic robustness + extrinsic robustness, then the stochastic coupled synthetic oscillators can be robustly synchronized in spite of intrinsic parameter fluctuation and extrinsic noise. If the synchronization robustness criterion is violated, external control scheme by adding inducer can be designed to improve synchronization robustness of coupled synthetic genetic oscillators. The investigated robust synchronization criteria and proposed external control method are useful for a population of coupled synthetic networks with emergent synchronization behavior, especially for multi-cellular, engineered networks. PMID:23101662

  7. Robust synchronization control scheme of a population of nonlinear stochastic synthetic genetic oscillators under intrinsic and extrinsic molecular noise via quorum sensing.

    Science.gov (United States)

    Chen, Bor-Sen; Hsu, Chih-Yuan

    2012-10-26

    toolbox in MATLAB easily. If the synchronization robustness criterion, i.e. the synchronization robustness ≥ intrinsic robustness + extrinsic robustness, then the stochastic coupled synthetic oscillators can be robustly synchronized in spite of intrinsic parameter fluctuation and extrinsic noise. If the synchronization robustness criterion is violated, external control scheme by adding inducer can be designed to improve synchronization robustness of coupled synthetic genetic oscillators. The investigated robust synchronization criteria and proposed external control method are useful for a population of coupled synthetic networks with emergent synchronization behavior, especially for multi-cellular, engineered networks.

  8. Robust synchronization control scheme of a population of nonlinear stochastic synthetic genetic oscillators under intrinsic and extrinsic molecular noise via quorum sensing

    Directory of Open Access Journals (Sweden)

    Chen Bor-Sen

    2012-10-01

    , which could be solved with the help of LMI toolbox in MATLAB easily. Conclusion If the synchronization robustness criterion, i.e. the synchronization robustness ≥ intrinsic robustness + extrinsic robustness, then the stochastic coupled synthetic oscillators can be robustly synchronized in spite of intrinsic parameter fluctuation and extrinsic noise. If the synchronization robustness criterion is violated, external control scheme by adding inducer can be designed to improve synchronization robustness of coupled synthetic genetic oscillators. The investigated robust synchronization criteria and proposed external control method are useful for a population of coupled synthetic networks with emergent synchronization behavior, especially for multi-cellular, engineered networks.

  9. Microbial Performance of Food Safety Control and Assurance Activities in a Fresh Produce Processing Sector Measured Using a Microbial Assessment Scheme and Statistical Modeling.

    Science.gov (United States)

    Njage, Patrick Murigu Kamau; Sawe, Chemutai Tonui; Onyango, Cecilia Moraa; Habib, I; Njagi, Edmund Njeru; Aerts, Marc; Molenberghs, Geert

    2017-01-01

    Current approaches such as inspections, audits, and end product testing cannot detect the distribution and dynamics of microbial contamination. Despite the implementation of current food safety management systems, foodborne outbreaks linked to fresh produce continue to be reported. A microbial assessment scheme and statistical modeling were used to systematically assess the microbial performance of core control and assurance activities in five Kenyan fresh produce processing and export companies. Generalized linear mixed models and correlated random-effects joint models for multivariate clustered data followed by empirical Bayes estimates enabled the analysis of the probability of contamination across critical sampling locations (CSLs) and factories as a random effect. Salmonella spp. and Listeria monocytogenes were not detected in the final products. However, none of the processors attained the maximum safety level for environmental samples. Escherichia coli was detected in five of the six CSLs, including the final product. Among the processing-environment samples, the hand or glove swabs of personnel revealed a higher level of predicted contamination with E. coli , and 80% of the factories were E. coli positive at this CSL. End products showed higher predicted probabilities of having the lowest level of food safety compared with raw materials. The final products were E. coli positive despite the raw materials being E. coli negative for 60% of the processors. There was a higher probability of contamination with coliforms in water at the inlet than in the final rinse water. Four (80%) of the five assessed processors had poor to unacceptable counts of Enterobacteriaceae on processing surfaces. Personnel-, equipment-, and product-related hygiene measures to improve the performance of preventive and intervention measures are recommended.

  10. Towards Symbolic Encryption Schemes

    DEFF Research Database (Denmark)

    Ahmed, Naveed; Jensen, Christian D.; Zenner, Erik

    2012-01-01

    , namely an authenticated encryption scheme that is secure under chosen ciphertext attack. Therefore, many reasonable encryption schemes, such as AES in the CBC or CFB mode, are not among the implementation options. In this paper, we report new attacks on CBC and CFB based implementations of the well...

  11. Multiresolution signal decomposition schemes

    NARCIS (Netherlands)

    J. Goutsias (John); H.J.A.M. Heijmans (Henk)

    1998-01-01

    textabstract[PNA-R9810] Interest in multiresolution techniques for signal processing and analysis is increasing steadily. An important instance of such a technique is the so-called pyramid decomposition scheme. This report proposes a general axiomatic pyramid decomposition scheme for signal analysis

  12. A Review of Two Payment Schemes for Watershed Services from China and Vietnam: the Interface of Government Control and PES Theory

    Directory of Open Access Journals (Sweden)

    Vijay K. Kolinjivadi

    2012-12-01

    Full Text Available China and Vietnam have developed some of the most ambitious payments for ecosystem services (PES initiatives for watershed conservation and forest management. These include the Sloping Land Conversion Programme in China and pilot projects designed to implement Decision 380 and the subsequent national PES law in Vietnam. This study reviews how these two government-driven initiatives are achieving their environment and development objectives in terms of their institutional arrangements, implementation in practice, and sustainability prospects. Although it remains too soon to determine the effects of these programs on watershed services, early evidence indicates that they are resulting in vulnerable land being retired from cultivation supported, in some cases, by considerable contributions to household income. A review of these initiatives has revealed two emerging questions that are relevant within the wider discussion on PES theory: (1 What is the ideal role for government in an evolving socio-cultural and political context? (2 What are the implications of a lack of voluntary participation in government administered PES schemes? Future prospects for harnessing the substantial political commitment for watershed protection toward more strategic, flexible, and long-term sustainable outcomes hinge on the ongoing responsiveness of these governments to stakeholder needs and objectives.

  13. Impulse Based Scheme for Crystal-less ULP Radios

    NARCIS (Netherlands)

    Drago, S.; Sebastiano, Fabio; Breems, Lucien J.; Leenaerts, Domine M.W.; Makinwa, Kofi A.A.; Nauta, Bram

    2009-01-01

    Abstract—This study describes a method of implementing a fully integrated ultra-low-power (ULP) radio for wireless sensor networks (WSNs). This is achieved using an ad hoc modulation scheme (impulse radio), with a bandwidth of 17.7 MHz in the 2.4 GHz—ISM band and a specific medium access control

  14. Evaluation of the subsidy scheme for heat pumps, pellet-fuelled fireplaces and control systems; Evaluering av tilskuddsordningen til varmepumper, pelletskaminer og styringssystemer

    Energy Technology Data Exchange (ETDEWEB)

    Bjoernstad, Even; Grande, Jorunn; Sand, Roar; Wendelborg, Christian

    2005-07-01

    Enova's subsidy scheme for energy economising in households was carried out in 2003. Subsidies were given to investments in heat pumps, pellet-fuelled fireplaces and electric energy management systems. The primary objective for this evaluation is to build knowledge about the effect of such subsidy schemes, and determine if they contribute to the reduction of electricity consumption in households. Questions that are addressed include Enova's administration of the subsidy scheme, the effects on households, the effects on the energy market, prices and technology. It is concluded that the scheme had a varied effect for the three technologies entitled to subsidies, and heat pump applications got 92,5 percent of the total sum. The households that received subsidies are in general positive, and the households that did not are in general not so satisfied with the service. It is concluded Enova has administered the subsidy scheme well, especially considering the time-frame and the changed economical conditions given (ml)

  15. Case studies on design, simulation and visualization of control and measurement applications using REX control system

    Science.gov (United States)

    Ozana, Stepan; Pies, Martin; Docekal, Tomas

    2016-06-01

    REX Control System is a professional advanced tool for design and implementation of complex control systems that belongs to softPLC category. It covers the entire process starting from simulation of functionality of the application before deployment, through implementation on real-time target, towards analysis, diagnostics and visualization. Basically it consists of two parts: the development tools and the runtime system. It is also compatible with Simulink environment, and the way of implementation of control algorithm is very similar. The control scheme is finally compiled (using RexDraw utility) and uploaded into a chosen real-time target (using RexView utility). There is a wide variety of hardware platforms and real-time operating systems supported by REX Control System such as for example Windows Embedded, Linux, Linux/Xenomai deployed on SBC, IPC, PAC, Raspberry Pi and others with many I/O interfaces. It is modern system designed both for measurement and control applications, offering a lot of additional functions concerning data archiving, visualization based on HTML5, and communication standards. The paper will sum up possibilities of its use in educational process, focused on control of case studies of physical models with classical and advanced control algorithms.

  16. Case studies on design, simulation and visualization of control and measurement applications using REX control system

    Energy Technology Data Exchange (ETDEWEB)

    Ozana, Stepan, E-mail: stepan.ozana@vsb.cz; Pies, Martin, E-mail: martin.pies@vsb.cz; Docekal, Tomas, E-mail: docekalt@email.cz [VSB-Technical University of Ostrava, Faculty of Electrical Engineering and Computer Science, Department of Cybernetics and Biomedical Engineering, 17. listopadu 15/2172, Ostrava-Poruba, 700 30 (Czech Republic)

    2016-06-08

    REX Control System is a professional advanced tool for design and implementation of complex control systems that belongs to softPLC category. It covers the entire process starting from simulation of functionality of the application before deployment, through implementation on real-time target, towards analysis, diagnostics and visualization. Basically it consists of two parts: the development tools and the runtime system. It is also compatible with Simulink environment, and the way of implementation of control algorithm is very similar. The control scheme is finally compiled (using RexDraw utility) and uploaded into a chosen real-time target (using RexView utility). There is a wide variety of hardware platforms and real-time operating systems supported by REX Control System such as for example Windows Embedded, Linux, Linux/Xenomai deployed on SBC, IPC, PAC, Raspberry Pi and others with many I/O interfaces. It is modern system designed both for measurement and control applications, offering a lot of additional functions concerning data archiving, visualization based on HTML5, and communication standards. The paper will sum up possibilities of its use in educational process, focused on control of case studies of physical models with classical and advanced control algorithms.

  17. Impact of alternative reimbursement strategies in the new cooperative medical scheme on caesarean delivery rates: a mixed-method study in rural China.

    Science.gov (United States)

    Huang, Kun; Tao, Fangbiao; Bogg, Lennart; Tang, Shenglan

    2012-07-24

    The rate of caesarean delivery (CD) in rural China has been rapidly increasing in recent decades. Due to the exorbitant costs associated with CD, paying for this expensive procedure is often a great challenge for the majority of rural families. Since 2003, the Chinese government has re-established the New Cooperative Medical Scheme (NCMS), aimed to improve the access of essential healthcare to rural residents and reduce financial burden owing to high out of pocket payments. This paper seeks to test the hypothesis that NCMS may provide service users and providers with financial incentives to select CD. It also assesses the effect of different health insurance reimbursement strategies of NCMS on CD rates in rural China. Mixed quantitative and qualitative methods were adopted for data collection. Two cross-sectional household surveys were conducted with women having babies delivered in 2006 and 2009; 2326 and 1515 women, respectively, from the study sites were interviewed using structured questionnaires, to collect demographic and socio-economic data, maternal and child care characteristics and health-related expenditures. Focus group discussions (FGDs) and in-depth key informant interviews (KIIs) were undertaken with policy makers, health managers, providers and mothers to understand their perceptions of the influence of NCMS on the choices of delivery mode. The CD rates in the two study counties were 46.0 percent and 64.7 percent in 2006, increasing to 63.6 percent and 82.1 percent, respectively, in 2009. The study found that decisions on the selection of CD largely came from the pregnant women. Logistic regression analysis, after adjusting for socio-economic, maternal and fetal characteristics, did not indicate a significant effect of either proportional reimbursement or fixed amount reimbursement on the choice of CD for both study years. Interviews with stakeholders reflected that different reimbursable rates for CD and vaginal deliveries did not have a

  18. Impact of alternative reimbursement strategies in the new cooperative medical scheme on caesarean delivery rates: a mixed-method study in rural China

    Directory of Open Access Journals (Sweden)

    Huang Kun

    2012-07-01

    Full Text Available Abstract Background The rate of caesarean delivery (CD in rural China has been rapidly increasing in recent decades. Due to the exorbitant costs associated with CD, paying for this expensive procedure is often a great challenge for the majority of rural families. Since 2003, the Chinese government has re-established the New Cooperative Medical Scheme (NCMS, aimed to improve the access of essential healthcare to rural residents and reduce financial burden owing to high out of pocket payments. This paper seeks to test the hypothesis that NCMS may provide service users and providers with financial incentives to select CD. It also assesses the effect of different health insurance reimbursement strategies of NCMS on CD rates in rural China. Methods Mixed quantitative and qualitative methods were adopted for data collection. Two cross-sectional household surveys were conducted with women having babies delivered in 2006 and 2009; 2326 and 1515 women, respectively, from the study sites were interviewed using structured questionnaires, to collect demographic and socio-economic data, maternal and child care characteristics and health-related expenditures. Focus group discussions (FGDs and in-depth key informant interviews (KIIs were undertaken with policy makers, health managers, providers and mothers to understand their perceptions of the influence of NCMS on the choices of delivery mode. Results The CD rates in the two study counties were 46.0 percent and 64.7 percent in 2006, increasing to 63.6 percent and 82.1 percent, respectively, in 2009. The study found that decisions on the selection of CD largely came from the pregnant women. Logistic regression analysis, after adjusting for socio-economic, maternal and fetal characteristics, did not indicate a significant effect of either proportional reimbursement or fixed amount reimbursement on the choice of CD for both study years. Interviews with stakeholders reflected that different reimbursable rates for

  19. Optics design for CEPC double ring scheme

    Science.gov (United States)

    Wang, Yiwei; Su, Feng; Bai, Sha; Yu, Chenghui; Gao, Jie

    2017-12-01

    The CEPC is a future Circular Electron and Positron Collider proposed by China to mainly study the Higgs boson. Its baseline design is a double ring scheme and an alternative design is a partial double ring scheme. This paper will present the optics design for the main ring of the double ring scheme. The CEPC will also work as a W and Z factory. Compatible optics designs for a W and a Z modes will be presented as well.

  20. Considerations of private sector obstetricians on participation in the state led "Chiranjeevi Yojana" scheme to promote institutional delivery in Gujarat, India: a qualitative study.

    Science.gov (United States)

    Ganguly, Parthasarathi; Jehan, Kate; de Costa, Ayesha; Mavalankar, Dileep; Smith, Helen

    2014-11-05

    In India a lack of access to emergency obstetric care contributes to maternal deaths. In 2005 Gujarat state launched a public-private partnership (PPP) programme, Chiranjeevi Yojana (CY), under which the state pays accredited private obstetricians a fixed fee for providing free intrapartum care to poor and tribal women. A million women have delivered under CY so far. The participation of private obstetricians in the partnership is central to the programme's effectiveness. We explored with private obstetricians the reasons and experiences that influenced their decisions to participate in the CY programme. In this qualitative study we interviewed 24 purposefully selected private obstetricians in Gujarat. We explored their views on the scheme, the reasons and experiences leading up to decisions to participate, not participate or withdraw from the CY, as well as their opinions about the scheme's impact. We analysed data using the Framework approach. Participants expressed a tension between doing public good and making a profit. Bureaucratic procedures and perceptions of programme misuse seemed to influence providers to withdraw from the programme or not participate at all. Providers feared that participating in CY would lower the status of their practices and some were deterred by the likelihood of more clinically difficult cases among eligible CY beneficiaries. Some providers resented taking on what they saw as a state responsibility to provide safe maternity services to poor women. Younger obstetricians in the process of establishing private practices, and those in more remote, 'less competitive' areas, were more willing to participate in CY. Some doctors had reservations over the quality of care that doctors could provide given the financial constraints of the scheme. While some private obstetricians willingly participate in CY and are satisfied with its functioning, a larger number shared concerns about participation. Operational difficulties and a trust deficit

  1. High order boron transport scheme in TRAC-BF1

    Energy Technology Data Exchange (ETDEWEB)

    Barrachina, Teresa; Jambrina, Ana; Miro, Rafael; Verdu, Gumersindo, E-mail: tbarrachina@iqn.upv.es, E-mail: rmiro@iqn.upv.es, E-mail: gverdu@iqn.upv.es [Universidade Politecnica de Valencia (UPV), Valencia, (Spain). Institute for the Industrial, Radiophysical and Environmental Safety; Soler, Amparo, E-mail: asoler@iberdrola.es [SEA Propulsion S.L., Madrid (Spain); Concejal, Alberto, E-mail: acbe@iberdrola.es [Iberdrola Ingenieria y Construcion S.A.U, Madrid (Spain)

    2013-07-01

    In boiling water reactors (BWR), unlike pressurized water reactors (PWR) in which the reactivity control is accomplished through movement of the control rods and boron dilution, the importance of boron transport lies in maintaining the core integrity during ATWS-kind severe accidents in which under certain circumstances a boron injection is required. This is the reason for implementing boron transport models thermal-hydraulic codes as TRAC-BF1, RELAP5 and TRACE, bringing an improvement in the accuracy of the simulations. TRAC-BF1 code provides a best estimate analysis capability for the analysis of the full range of postulated accidents in boiling water reactors systems and related facilities. The boron transport model implemented in TRAC-BF1 code is based on a calculation according to a first order accurate upwind difference scheme. There is a need in reviewing and improving this model. Four numerical schemes that solve the boron transport model have been analyzed and compared with the analytical solution that provides the Burgers equation. The studied numerical schemes are: first order Upwind, second order Godunov, second-order modified Godunov adding physical diffusion term and a third-order QUICKEST using the ULTIMATE universal limiter (UL). The modified Godunov scheme has been implemented in TRAC-BF1 source code. The results using these new schemes are presented in this paper. (author)

  2. New concept of direct torque neuro-fuzzy control for induction motor drives. Simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Grabowski, P.Z. [Institute of Control and Industrial Electronics, Warsaw University of Technology, Warsaw (Poland)

    1997-12-31

    This paper presents a new control strategy in the discrete Direct Torque Control (DTC) based on neuro-fuzzy structure. Two schemes are proposed: neuro-fuzzy switching times calculator and neuro-fuzzy incremental controller with space vector modulator. These control strategies guarantee very good dynamic and steady-states characteristics, with very low sampling time and constant switching frequency. The proposed techniques are verified by simulation study of the whole drive system and results are compared with conventional discrete Direct Torque Control method. (orig.) 18 refs.

  3. Tabled Execution in Scheme

    Energy Technology Data Exchange (ETDEWEB)

    Willcock, J J; Lumsdaine, A; Quinlan, D J

    2008-08-19

    Tabled execution is a generalization of memorization developed by the logic programming community. It not only saves results from tabled predicates, but also stores the set of currently active calls to them; tabled execution can thus provide meaningful semantics for programs that seemingly contain infinite recursions with the same arguments. In logic programming, tabled execution is used for many purposes, both for improving the efficiency of programs, and making tasks simpler and more direct to express than with normal logic programs. However, tabled execution is only infrequently applied in mainstream functional languages such as Scheme. We demonstrate an elegant implementation of tabled execution in Scheme, using a mix of continuation-passing style and mutable data. We also show the use of tabled execution in Scheme for a problem in formal language and automata theory, demonstrating that tabled execution can be a valuable tool for Scheme users.

  4. Construction of Low Dissipative High Order Well-Balanced Filter Schemes for Non-Equilibrium Flows

    Science.gov (United States)

    Wang, Wei; Yee, H. C.; Sjogreen, Bjorn; Magin, Thierry; Shu, Chi-Wang

    2009-01-01

    The goal of this paper is to generalize the well-balanced approach for non-equilibrium flow studied by Wang et al. [26] to a class of low dissipative high order shock-capturing filter schemes and to explore more advantages of well-balanced schemes in reacting flows. The class of filter schemes developed by Yee et al. [30], Sjoegreen & Yee [24] and Yee & Sjoegreen [35] consist of two steps, a full time step of spatially high order non-dissipative base scheme and an adaptive nonlinear filter containing shock-capturing dissipation. A good property of the filter scheme is that the base scheme and the filter are stand alone modules in designing. Therefore, the idea of designing a well-balanced filter scheme is straightforward, i.e., choosing a well-balanced base scheme with a well-balanced filter (both with high order). A typical class of these schemes shown in this paper is the high order central difference schemes/predictor-corrector (PC) schemes with a high order well-balanced WENO filter. The new filter scheme with the well-balanced property will gather the features of both filter methods and well-balanced properties: it can preserve certain steady state solutions exactly; it is able to capture small perturbations, e.g., turbulence fluctuations; it adaptively controls numerical dissipation. Thus it shows high accuracy, efficiency and stability in shock/turbulence interactions. Numerical examples containing 1D and 2D smooth problems, 1D stationary contact discontinuity problem and 1D turbulence/shock interactions are included to verify the improved accuracy, in addition to the well-balanced behavior.

  5. 6. Analisis Implementasi Cyber Security Di Uni Eropa: Studi Kasus Carbon Credits Hacking Dalam European Union Emission Trading Scheme (EU ETS) Tahun 2010-2013

    OpenAIRE

    Aisya, Naila Sukma; Putranti, Ika Riswanti; Wahyudi, Fendy Eko

    2017-01-01

    Since the last two decades in the 20th century, the European Union (EU) has presented itself as a leader in climate change issues. The leadership manifested in the formation of the European Union Emission Trading Scheme (EU ETS) as an effort to fulfill the commitments of the Kyoto Protocol to reduce emissions in the region. But the existence of the EU ETS has been challenged by the emergence of carbon credits hacking case in some national registration systems in the EU ETS. This study discuss...

  6. A Performance Study on Synchronous and Asynchronous Update Rules for A Plug-In Direct Particle Swarm Repetitive Controller

    Directory of Open Access Journals (Sweden)

    Ufnalski Bartlomiej

    2014-12-01

    Full Text Available In this paper two different update schemes for the recently developed plug-in direct particle swarm repetitive controller (PDPSRC are investigated and compared. The proposed approach employs the particle swarm optimizer (PSO to solve in on-line mode a dynamic optimization problem (DOP related to the control task in the constant-amplitude constant-frequency voltage-source inverter (CACF VSI with an LC output filter. The effectiveness of synchronous and asynchronous update rules, both commonly used in static optimization problems (SOPs, is assessed and compared in the case of PDPSRC. The performance of the controller, when synthesized using each of the update schemes, is studied numerically.

  7. Surrogate Model Application to the Identification of Optimal Groundwater Exploitation Scheme Based on Regression Kriging Method-A Case Study of Western Jilin Province.

    Science.gov (United States)

    An, Yongkai; Lu, Wenxi; Cheng, Weiguo

    2015-07-30

    This paper introduces a surrogate model to identify an optimal exploitation scheme, while the western Jilin province was selected as the study area. A numerical simulation model of groundwater flow was established first, and four exploitation wells were set in the Tongyu county and Qian Gorlos county respectively so as to supply water to Daan county. Second, the Latin Hypercube Sampling (LHS) method was used to collect data in the feasible region for input variables. A surrogate model of the numerical simulation model of groundwater flow was developed using the regression kriging method. An optimization model was established to search an optimal groundwater exploitation scheme using the minimum average drawdown of groundwater table and the minimum cost of groundwater exploitation as multi-objective functions. Finally, the surrogate model was invoked by the optimization model in the process of solving the optimization problem. Results show that the relative error and root mean square error of the groundwater table drawdown between the simulation model and the surrogate model for 10 validation samples are both lower than 5%, which is a high approximation accuracy. The contrast between the surrogate-based simulation optimization model and the conventional simulation optimization model for solving the same optimization problem, shows the former only needs 5.5 hours, and the latter needs 25 days. The above results indicate that the surrogate model developed in this study could not only considerably reduce the computational burden of the simulation optimization process, but also maintain high computational accuracy. This can thus provide an effective method for identifying an optimal groundwater exploitation scheme quickly and accurately.

  8. A case-study of landfill minimization and material recovery via waste co-gasification in a new waste management scheme.

    Science.gov (United States)

    Tanigaki, Nobuhiro; Ishida, Yoshihiro; Osada, Morihiro

    2015-03-01

    This study evaluates municipal solid waste co-gasification technology and a new solid waste management scheme, which can minimize final landfill amounts and maximize material recycled from waste. This new scheme is considered for a region where bottom ash and incombustibles are landfilled or not allowed to be recycled due to their toxic heavy metal concentration. Waste is processed with incombustible residues and an incineration bottom ash discharged from existent conventional incinerators, using a gasification and melting technology (the Direct Melting System). The inert materials, contained in municipal solid waste, incombustibles and bottom ash, are recycled as slag and metal in this process as well as energy recovery. Based on this new waste management scheme with a co-gasification system, a case study of municipal solid waste co-gasification was evaluated and compared with other technical solutions, such as conventional incineration, incineration with an ash melting facility under certain boundary conditions. From a technical point of view, co-gasification produced high quality slag with few harmful heavy metals, which was recycled completely without requiring any further post-treatment such as aging. As a consequence, the co-gasification system had an economical advantage over other systems because of its material recovery and minimization of the final landfill amount. Sensitivity analyses of landfill cost, power price and inert materials in waste were also conducted. The higher the landfill costs, the greater the advantage of the co-gasification system has. The co-gasification was beneficial for landfill cost in the range of 80 Euro per ton or more. Higher power prices led to lower operation cost in each case. The inert contents in processed waste had a significant influence on the operating cost. These results indicate that co-gasification of bottom ash and incombustibles with municipal solid waste contributes to minimizing the final landfill amount and has

  9. Alternating irrigation water quality as a method to control solute concentrations and mass fluxes below irrigated fields: A numerical study

    Science.gov (United States)

    Russo, David

    2016-05-01

    The aim of the present numerical study was to extend the data-driven protocol for the control of soil salinity, to control chloride and nitrate concentrations and mass fluxes below agricultural fields irrigated with treated waste water (TWW). The protocol is based on alternating irrigation water quality between TWW and desalinized water (DSW), guided by solute concentrations at soil depth, zs. Two different schemes, the first requires measurements of soil solution concentrations of chloride and nitrate at zs, while, the second scheme requires only measurements of soil solution EC at zs, were investigated. For this purpose, 3-D numerical simulations of flow and transport were performed for variably saturated, spatially heterogeneous, flow domains located at two different field sites. The sites differ in crop type, irrigation method, and in their lithology; these differences, in turn, considerably affect the performance of the proposed schemes, expressed in terms of their ability to reduce solute concentrations that drained below the root zone. Results of the analyses suggest that the proposed data-driven schemes allow the use of low-quality water for irrigation, while minimizing the consumption of high-quality water to a level, which, for given climate, soil, crop, irrigation method, and water quality, may be determined by the allowable nitrate and chloride concentrations in the groundwater. The results of the present study indicate that with respect to the diminution of groundwater contamination by chloride and nitrate, the more data demanding, first scheme is superior the second scheme.

  10. Control of a Robotic Hand Using a Tongue Control System-A Prosthesis Application.

    Science.gov (United States)

    Johansen, Daniel; Cipriani, Christian; Popovic, Dejan B; Struijk, Lotte N S A

    2016-07-01

    The aim of this study was to investigate the feasibility of using an inductive tongue control system (ITCS) for controlling robotic/prosthetic hands and arms. This study presents a novel dual modal control scheme for multigrasp robotic hands combining standard electromyogram (EMG) with the ITCS. The performance of the ITCS control scheme was evaluated in a comparative study. Ten healthy subjects used both the ITCS control scheme and a conventional EMG control scheme to complete grasping exercises with the IH1 Azzurra robotic hand implementing five grasps. Time to activate a desired function or grasp was used as the performance metric. Statistically significant differences were found when comparing the performance of the two control schemes. On average, the ITCS control scheme was 1.15 s faster than the EMG control scheme, corresponding to a 35.4% reduction in the activation time. The largest difference was for grasp 5 with a mean AT reduction of 45.3% (2.38 s). The findings indicate that using the ITCS control scheme could allow for faster activation of specific grasps or functions compared with a conventional EMG control scheme. For transhumeral and especially bilateral amputees, the ITCS control scheme could have a significant impact on the prosthesis control. In addition, the ITCS would provide bilateral amputees with the additional advantage of environmental and computer control for which the ITCS was originally developed.

  11. A Temporal Credential-Based Mutual Authentication with Multiple-Password Scheme for Wireless Sensor Networks.

    Science.gov (United States)

    Liu, Xin; Zhang, Ruisheng; Liu, Qidong

    2017-01-01

    Wireless sensor networks (WSNs), which consist of a large number of sensor nodes, have become among the most important technologies in numerous fields, such as environmental monitoring, military surveillance, control systems in nuclear reactors, vehicle safety systems, and medical monitoring. The most serious drawback for the widespread application of WSNs is the lack of security. Given the resource limitation of WSNs, traditional security schemes are unsuitable. Approaches toward withstanding related attacks with small overhead have thus recently been studied by many researchers. Numerous studies have focused on the authentication scheme for WSNs, but most of these works cannot achieve the security performance and overhead perfectly. Nam et al. proposed a two-factor authentication scheme with lightweight sensor computation for WSNs. In this paper, we review this scheme, emphasize its drawbacks, and propose a temporal credential-based mutual authentication with a multiple-password scheme for WSNs. Our scheme uses multiple passwords to achieve three-factor security performance and generate a session key between user and sensor nodes. The security analysis phase shows that our scheme can withstand related attacks, including a lost password threat, and the comparison phase shows that our scheme involves a relatively small overhead. In the comparison of the overhead phase, the result indicates that more than 95% of the overhead is composed of communication and not computation overhead. Therefore, the result motivates us to pay further attention to communication overhead than computation overhead in future research.

  12. Passive fault tolerant control of a double inverted pendulum - a case study

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, Jakob

    2005-01-01

    A passive fault tolerant control scheme is suggested, in which a nominal controller is augmented with an additional block, which guarantees stability and performance after the occurrence of a fault. The method is based on the YJBK parameterization, which requires the nominal controller to be impl...... to be implemented in observer based form. The proposed method is applied to a double inverted pendulum system, for which an H_inf controller has been designed and verified in a lab setup. In this case study, the fault is a degradation of the tacho loop....

  13. Voluntary agreements, implementation and efficiency. European relevance of case study results. Reflections on transferability to voluntary agreement schemes at the European level

    Energy Technology Data Exchange (ETDEWEB)

    Helby, Peter

    2000-04-01

    As a policy instrument, voluntary agreements often fascinate policy-makers.This is fuelled by a number of assumed advantages, such as the opportunity for co-operation rather than confrontation, speed and flexibility and the cost-effectiveness. Some advantages might even be accentuated at the European level: Co-operation has added advantage at the European level where the culture of consensus decision is strong. Flexibility is extra attractive for policy makers dealing with an economy less homogeneous than the average national economy. Speed is certainly welcomed by policy-makers otherwise faced with the slow-winding European legislative process. Cost-effectiveness is eagerly sought by European policy makers facing tight administrative budgets and staff limits. This report examines lessons from the VAIE case studies that may be useful to policy makers engaged in the development of voluntary approaches at the European level. These case studies are about voluntary agreement schemes for industrial energy efficiency deployed in Denmark, France, Germany, Netherlands, and Sweden. For a summary of these case studies, please refer to the the VAIE final report. More detailed information is available in the VAIE national reports. It needs to be emphasised that the empirical base is very narrow. The 'lessons' presented can only be hypotheses, based on an inductive leap from a very narrow experience. The reader will need to check these hypotheses against her own broader experience and personal judgement. According to the principle of subsidiarity, voluntary agreements should be implemented at the European level only if that would have significant advantage over national action. Action at the European level, rather than the national level, would have these potential advantages: Being more consistent with the development of the single market; Allowing higher demands on energy efficiency without negative effect on competitiveness and employment; Stimulating company

  14. Evaluation of the MPATH-Dx Classification Scheme for Diagnosis of Cutaneous Melanocytic Neoplasms: Results from the International Melanoma Pathology Study Group

    Science.gov (United States)

    Lott, Jason P.; Elmore, Joann; Zhao, Ge A.; Knezevich, Stevan R.; Frederick, Paul D.; Reisch, Lisa M.; Chu, Emily Y.; Cook, Martin G.; Duncan, Lyn M.; Elenitsas, Rosalie; Gerami, Pedram; Landman, Gilles; Lowe, Lori; Messina, Jane L.; Mihm, Martin C.; van den Oord, Joost J.; Rabkin, Michael S.; Schmidt, Birgitta; Shea, Christopher R.; Yun, Sook Jung; Xu, George X.; Piepkorn, Michael W.; Elder, David E.; Barnhill, Raymond L.

    2016-01-01

    Background Pathologists use diverse terminology when interpreting melanocytic neoplasms, potentially compromising quality of care. Objective To evaluate the Melanoma Pathology Assessment and Treatment Hierarchy (MPATH-Dx) scheme, a five-category classification system for melanocytic lesions. Methods Participants (n=16) of the 2013 International Melanoma Pathology Study Group Workshop provided independent case-level diagnoses and treatment suggestions for 48 melanocytic lesions. Individual diagnoses (including, when provided, least and most severe diagnoses) were mapped to corresponding MPATH-Dx classes. Inter-rater agreement [95% CI] and correlation between MPATH-Dx categorization and treatment suggestions were evaluated. Results Most participants were dermatopathologists (n=12), age ≥50 years (n=12), male (n=9), US-based (n=11), and primary academic faculty (n=14). Overall, participants generated 634 case-level diagnoses with treatment suggestions. Mean weighted kappa coefficients for diagnostic agreement following MPATH-Dx mapping (assuming least and most severe diagnoses, when necessary) were 0.70 [0.68, 0.71] and 0.72 [0.71, 0.73], respectively, while correlation between MPATH-Dx categorization and treatment suggestions was 0.91. Limitations Small sample size of experienced pathologists in a testing situation. Conclusion Varying diagnostic nomenclature can be consistently classified into a concise hierarchy using the MPATH-Dx scheme. Further research is needed to determine whether this classification system can facilitate diagnostic concordance in general pathology practice and improve patient care. PMID:27189823

  15. Compact Spreader Schemes

    Energy Technology Data Exchange (ETDEWEB)

    Placidi, M.; Jung, J. -Y.; Ratti, A.; Sun, C.

    2014-07-25

    This paper describes beam distribution schemes adopting a novel implementation based on low amplitude vertical deflections combined with horizontal ones generated by Lambertson-type septum magnets. This scheme offers substantial compactness in the longitudinal layouts of the beam lines and increased flexibility for beam delivery of multiple beam lines on a shot-to-shot basis. Fast kickers (FK) or transverse electric field RF Deflectors (RFD) provide the low amplitude deflections. Initially proposed at the Stanford Linear Accelerator Center (SLAC) as tools for beam diagnostics and more recently adopted for multiline beam pattern schemes, RFDs offer repetition capabilities and a likely better amplitude reproducibility when compared to FKs, which, in turn, offer more modest financial involvements both in construction and operation. Both solutions represent an ideal approach for the design of compact beam distribution systems resulting in space and cost savings while preserving flexibility and beam quality.

  16. Nonlinear Control of Induction Motors: A Performance Study

    DEFF Research Database (Denmark)

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

    1998-01-01

    A novel approach to control of induction motors based on nonlinear state feedback has previously been presented by the authors. The resulting scheme gives a linearized input-output decoupling of the torque and the amplitude of the field. The proposed approach is used to design controllers...... for the field amplitude and the motor torque. The method is compared with the traditional Rotor Field Oriented Control method as regards variations in rotor resistance an magnetizing inductance...

  17. Controlled study of ISA effects

    DEFF Research Database (Denmark)

    Harms, Lisbeth; Klarborg, Brith; Lahrmann, Harry

    2007-01-01

    The present study is a part of the ISA PAYD project being conducted in the County of North Jutland, Denmark. The first part of the study compared background data and attitudes between young ISA-volunteers and non-volunteers. Volunteers and nonvolunteers differed only with respect to their judgeme...

  18. Coordinated voltage control scheme for distribution grid with on-load tap-changer and distributed energy resources in a market context

    DEFF Research Database (Denmark)

    Han, Xue; Bindner, Henrik W.; Mehmedalic, Jasmin

    2015-01-01

    The evolutionary changes in the electricity system are reshaping the system operation and control to achieve a more sustainable environment. In this transition, distributed energy resources (DERs) may introduce some problems, such as intermittent features, but could also play an important role on...... for case study. The necessity of the coordination between DER units and the grid facilities, e.g., on-load tap-changer (OLTC), is addressed....

  19. Impact of China's essential medicines scheme and zero-mark-up policy on antibiotic prescriptions in county hospitals: a mixed methods study.

    Science.gov (United States)

    Wei, Xiaolin; Yin, Jia; Walley, John D; Zhang, Zhitong; Hicks, Joseph P; Zhou, Yu; Sun, Qiang; Zeng, Jun; Lin, Mei

    2017-09-01

    To evaluate the impact of the national essential medicines scheme and zero-mark-up policy on antibiotic prescribing behaviour. In rural Guangxi, a natural experiment compared one county hospital which implemented the policy with a comparison hospital which did not. All outpatient and inpatient records in 2011 and 2014 were extracted from the two hospitals. Primary outcome indicator was antibiotic prescribing rate (APR) among children aged 2-14 presenting in outpatients with a primary diagnosis of upper respiratory tract infection (URTI). We organised independent physician reviews to determine inappropriate prescribing for inpatients. Difference-in-difference analyses based on multivariate regressions were used to compare APR over time after adjusting potential confounders. We conducted 12 in-depth interviews with paediatricians, hospital directors and health officials. A total of 8219 and 4142 outpatient prescriptions of childhood URTIs were included in the intervention and comparison hospitals, respectively. In 2011, APR was 30% in the intervention and 88% in the comparison hospital. In 2014, the intervention hospital significantly reduced outpatient APR by 21% (95% CI:-23%, -18%), intravenous infusion by 58% (95% CI: -64%, -52%) and prescription cost by 31 USD (95% CI: -35, -28), compared with the controls. We collected 251 inpatient records, but did not find reductions in inappropriate antibiotic use. Interviews revealed that the intervention hospital implemented a thorough antibiotics stewardship programme containing training, peer review of prescriptions and restrictions for overprescribing. The national essential medicines scheme and zero-mark-up policy, when implemented with an antimicrobial stewardship programme, may be associated with reductions in outpatient antibiotic prescribing and intravenous infusions. © 2017 John Wiley & Sons Ltd.

  20. Effects of a structured physical-activity counseling and referral scheme in long-term unemployed individuals: a pilot accelerometer study.

    Science.gov (United States)

    Gabrys, Lars; Michallik, Lisa; Thiel, Christian; Vogt, Lutz; Banzer, Winfried

    2013-01-01

    Unemployment is associated with health risks. Physical activity produces health benefits. This study examined the effects of a physical activity counseling and exercise referral scheme on physical-activity behavior in long-term unemployed individuals. In this study, 51 long-term unemployed persons received physical-activity counseling and exercise referral. Further, 21 unemployed and 17 employed persons with no intervention were included. Physical activity was measured over 7 consecutive days prior to and 12 weeks after counseling by accelerometer. Participants who started exercising increased their amount of moderate physical activity from 26 ± 14 to 35 ± 25 minutes/day and total physical activity from 207 ± 86 to 288 ± 126 counts/minute. Generally, unemployed persons were less active and less healthy compared to employed persons. Persons who are willing and motivated benefit from structured physical activity counseling and exercise referral and increase physical activity to a health promoting level. Physical activity inequalities could be reduced.