Research on frequency control strategy of interconnected region based on fuzzy PID

NASA Astrophysics Data System (ADS)

Zhang, Yan; Li, Chunlan

2018-05-01

In order to improve the frequency control performance of the interconnected power grid, overcome the problems of poor robustness and slow adjustment of traditional regulation, the paper puts forward a frequency control method based on fuzzy PID. The method takes the frequency deviation and tie-line deviation of each area as the control objective, takes the regional frequency deviation and its deviation as input, and uses fuzzy mathematics theory, adjusts PID control parameters online. By establishing the regional frequency control model of water-fire complementary power generation in MATLAB, the regional frequency control strategy is given, and three control modes (TBC-FTC, FTC-FTC, FFC-FTC) are simulated and analyzed. The simulation and experimental results show that, this method has better control performance compared with the traditional regional frequency regulation.

A Review of Control Strategy of the Large-scale of Electric Vehicles Charging and Discharging Behavior

NASA Astrophysics Data System (ADS)

Kong, Lingyu; Han, Jiming; Xiong, Wenting; Wang, Hao; Shen, Yaqi; Li, Ying

2017-05-01

Large scale access of electric vehicles will bring huge challenges to the safe operation of the power grid, and it’s important to control the charging and discharging of the electric vehicle. First of all, from the electric quality and network loss, this paper points out the influence on the grid caused by electric vehicle charging behaviour. Besides, control strategy of electric vehicle charging and discharging has carried on the induction and the summary from the direct and indirect control. Direct control strategy means control the electric charging behaviour by controlling its electric vehicle charging and discharging power while the indirect control strategy by means of controlling the price of charging and discharging. Finally, for the convenience of the reader, this paper also proposed a complete idea of the research methods about how to study the control strategy, taking the adaptability and possibility of failure of electric vehicle control strategy into consideration. Finally, suggestions on the key areas for future research are put up.

Simple adaptive control system design for a quadrotor with an internal PFC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mizumoto, Ikuro; Nakamura, Takuto; Kumon, Makoto

2014-12-10

The paper deals with an adaptive control system design problem for a four rotor helicopter or quadrotor. A simple adaptive control design scheme with a parallel feedforward compensator (PFC) in the internal loop of the considered quadrotor will be proposed based on the backstepping strategy. As is well known, the backstepping control strategy is one of the advanced control strategy for nonlinear systems. However, the control algorithm will become complex if the system has higher order relative degrees. We will show that one can skip some design steps of the backstepping method by introducing a PFC in the inner loopmore » of the considered quadrotor, so that the structure of the obtained controller will be simplified and a high gain based adaptive feedback control system will be designed. The effectiveness of the proposed method will be confirmed through numerical simulations.« less

Reynolds number dependence of large-scale friction control in turbulent channel flow

NASA Astrophysics Data System (ADS)

Canton, Jacopo; Örlü, Ramis; Chin, Cheng; Schlatter, Philipp

2016-12-01

The present work investigates the effectiveness of the control strategy introduced by Schoppa and Hussain [Phys. Fluids 10, 1049 (1998), 10.1063/1.869789] as a function of Reynolds number (Re). The skin-friction drag reduction method proposed by these authors, consisting of streamwise-invariant, counter-rotating vortices, was analyzed by Canton et al. [Flow, Turbul. Combust. 97, 811 (2016), 10.1007/s10494-016-9723-8] in turbulent channel flows for friction Reynolds numbers (Reτ) corresponding to the value of the original study (i.e., 104) and 180. For these Re, a slightly modified version of the method proved to be successful and was capable of providing a drag reduction of up to 18%. The present study analyzes the Reynolds number dependence of this drag-reducing strategy by performing two sets of direct numerical simulations (DNS) for Reτ=360 and 550. A detailed analysis of the method as a function of the control parameters (amplitude and wavelength) and Re confirms, on the one hand, the effectiveness of the large-scale vortices at low Re and, on the other hand, the decreasing and finally vanishing effectiveness of this method for higher Re. In particular, no drag reduction can be achieved for Reτ=550 for any combination of the parameters controlling the vortices. For low Reynolds numbers, the large-scale vortices are able to affect the near-wall cycle and alter the wall-shear-stress distribution to cause an overall drag reduction effect, in accordance with most control strategies. For higher Re, instead, the present method fails to penetrate the near-wall region and cannot induce the spanwise velocity variation observed in other more established control strategies, which focus on the near-wall cycle. Despite the negative outcome, the present results demonstrate the shortcomings of the control strategy and show that future focus should be on methods that directly target the near-wall region or other suitable alternatives.

A nonlinear strategy for sensor based vehicle path control

NASA Technical Reports Server (NTRS)

Mayr, R.

1994-01-01

A method of transverse control which makes use of nonlinear formulations is presented. The strategy is utilized to stabilize a vehicle. The vehicle is autonomously guided and takes its control inputs from an optical sensing system. Additionally, the velocity of the vehicle is dictated by a longitudinal controller, which is also discussed.

Distributed Evaluation Functions for Fault Tolerant Multi-Rover Systems

NASA Technical Reports Server (NTRS)

Agogino, Adrian; Turner, Kagan

2005-01-01

The ability to evolve fault tolerant control strategies for large collections of agents is critical to the successful application of evolutionary strategies to domains where failures are common. Furthermore, while evolutionary algorithms have been highly successful in discovering single-agent control strategies, extending such algorithms to multiagent domains has proven to be difficult. In this paper we present a method for shaping evaluation functions for agents that provide control strategies that both are tolerant to different types of failures and lead to coordinated behavior in a multi-agent setting. This method neither relies of a centralized strategy (susceptible to single point of failures) nor a distributed strategy where each agent uses a system wide evaluation function (severe credit assignment problem). In a multi-rover problem, we show that agents using our agent-specific evaluation perform up to 500% better than agents using the system evaluation. In addition we show that agents are still able to maintain a high level of performance when up to 60% of the agents fail due to actuator, communication or controller faults.

An optimal control strategy for hybrid actuator systems: Application to an artificial muscle with electric motor assist.

PubMed

Ishihara, Koji; Morimoto, Jun

2018-03-01

Humans use multiple muscles to generate such joint movements as an elbow motion. With multiple lightweight and compliant actuators, joint movements can also be efficiently generated. Similarly, robots can use multiple actuators to efficiently generate a one degree of freedom movement. For this movement, the desired joint torque must be properly distributed to each actuator. One approach to cope with this torque distribution problem is an optimal control method. However, solving the optimal control problem at each control time step has not been deemed a practical approach due to its large computational burden. In this paper, we propose a computationally efficient method to derive an optimal control strategy for a hybrid actuation system composed of multiple actuators, where each actuator has different dynamical properties. We investigated a singularly perturbed system of the hybrid actuator model that subdivided the original large-scale control problem into smaller subproblems so that the optimal control outputs for each actuator can be derived at each control time step and applied our proposed method to our pneumatic-electric hybrid actuator system. Our method derived a torque distribution strategy for the hybrid actuator by dealing with the difficulty of solving real-time optimal control problems. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Model-based control strategies for systems with constraints of the program type

NASA Astrophysics Data System (ADS)

Jarzębowska, Elżbieta

2006-08-01

The paper presents a model-based tracking control strategy for constrained mechanical systems. Constraints we consider can be material and non-material ones referred to as program constraints. The program constraint equations represent tasks put upon system motions and they can be differential equations of orders higher than one or two, and be non-integrable. The tracking control strategy relies upon two dynamic models: a reference model, which is a dynamic model of a system with arbitrary order differential constraints and a dynamic control model. The reference model serves as a motion planner, which generates inputs to the dynamic control model. It is based upon a generalized program motion equations (GPME) method. The method enables to combine material and program constraints and merge them both into the motion equations. Lagrange's equations with multipliers are the peculiar case of the GPME, since they can be applied to systems with constraints of first orders. Our tracking strategy referred to as a model reference program motion tracking control strategy enables tracking of any program motion predefined by the program constraints. It extends the "trajectory tracking" to the "program motion tracking". We also demonstrate that our tracking strategy can be extended to a hybrid program motion/force tracking.

Compound Velocity Synchronizing Control Strategy for Electro-Hydraulic Load Simulator and Its Engineering Application.

PubMed

Han, Songshan; Jiao, Zongxia; Yao, Jianyong; Shang, Yaoxing

2014-09-01

An electro-hydraulic load simulator (EHLS) is a typical case of torque systems with strong external disturbances from hydraulic motion systems. A new velocity synchronizing compensation strategy is proposed in this paper to eliminate motion disturbances, based on theoretical and experimental analysis of a structure invariance method and traditional velocity synchronizing compensation controller (TVSM). This strategy only uses the servo-valve's control signal of motion system and torque feedback of torque system, which could avoid the requirement on the velocity and acceleration signal in the structure invariance method, and effectively achieve a more accurate velocity synchronizing compensation in large loading conditions than a TVSM. In order to facilitate the implementation of this strategy in engineering cases, the selection rules for compensation parameters are proposed. It does not rely on any accurate information of structure parameters. This paper presents the comparison data of an EHLS with various typical operating conditions using three controllers, i.e., closed loop proportional integral derivative (PID) controller, TVSM, and the proposed improved velocity synchronizing controller. Experiments are conducted to confirm that the new strategy performs well against motion disturbances. It is more effective to improve the tracking accuracy and is a more appropriate choice for engineering applications.

The Myriad Strategies for Seeking Control in the Dying Process

ERIC Educational Resources Information Center

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

2009-01-01

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

Simulation of traffic control signal systems

NASA Technical Reports Server (NTRS)

Connolly, P. J.; Concannon, P. A.; Ricci, R. C.

1974-01-01

In recent years there has been considerable interest in the development and testing of control strategies for networks of urban traffic signal systems by simulation. Simulation is an inexpensive and timely method for evaluating the effect of these traffic control strategies since traffic phenomena are too complex to be defined by analytical models and since a controlled experiment may be hazardous, expensive, and slow in producing meaningful results. This paper describes the application of an urban traffic corridor program, to evaluate the effectiveness of different traffic control strategies for the Massachusetts Avenue TOPICS Project.

Aerodynamic load control strategy of wind turbine in microgrid

NASA Astrophysics Data System (ADS)

Wang, Xiangming; Liu, Heshun; Chen, Yanfei

2017-12-01

A control strategy is proposed in the paper to optimize the aerodynamic load of the wind turbine in micro-grid. In grid-connection mode, the wind turbine adopts a new individual variable pitch control strategy. The pitch angle of the blade is rapidly given by the controller, and the pitch angle of each blade is fine tuned by the weight coefficient distributor. In islanding mode, according to the requirements of energy storage system, a given power tracking control method based on fuzzy PID control is proposed. Simulation result shows that this control strategy can effectively improve the axial aerodynamic load of the blade under rated wind speed in grid-connection mode, and ensure the smooth operation of the micro-grid in islanding mode.

Formation Control for Water-Jet USV Based on Bio-Inspired Method

NASA Astrophysics Data System (ADS)

Fu, Ming-yu; Wang, Duan-song; Wang, Cheng-long

2018-03-01

The formation control problem for underactuated unmanned surface vehicles (USVs) is addressed by a distributed strategy based on virtual leader strategy. The control system takes account of disturbance induced by external environment. With the coordinate transformation, the advantage of the proposed scheme is that the control point can be any point of the ship instead of the center of gravity. By introducing bio-inspired model, the formation control problem is addressed with backstepping method. This avoids complicated computation, simplifies the control law, and smoothes the input signals. The system uniform ultimate boundness is proven by Lyapunov stability theory with Young inequality. Simulation results are presented to verify the effectiveness and robust of the proposed controller.

Capacity value of energy storage considering control strategies.

PubMed

Shi, Nian; Luo, Yi

2017-01-01

In power systems, energy storage effectively improves the reliability of the system and smooths out the fluctuations of intermittent energy. However, the installed capacity value of energy storage cannot effectively measure the contribution of energy storage to the generator adequacy of power systems. To achieve a variety of purposes, several control strategies may be utilized in energy storage systems. The purpose of this paper is to study the influence of different energy storage control strategies on the generation adequacy. This paper presents the capacity value of energy storage to quantitatively estimate the contribution of energy storage on the generation adequacy. Four different control strategies are considered in the experimental method to study the capacity value of energy storage. Finally, the analysis of the influence factors on the capacity value under different control strategies is given.

Implementation of Push Recovery Strategy Using Triple Linear Inverted Pendulum Model in “T-FloW” Humanoid Robot

NASA Astrophysics Data System (ADS)

Dimas Pristovani, R.; Raden Sanggar, D.; Dadet, Pramadihanto.

2018-04-01

Push recovery is one of humanbehaviorwhich is a strategy to defend the body from anexternal force in any environment. This paper describes push recovery strategy which usesMIMO decoupled control system method. The dynamics system uses aquasi-dynamic system based on triple linear inverted pendulum model (TLIPM). The analysis of TLIPMuses zero moment point (ZMP) calculation from ZMP simplification in last research. By using this simplification of dynamics system, the control design can be simplified into 3 serial SISOwith known and uncertain disturbance models in each inverted pendulum. Each pendulum has different plan to damp the external force effect. In this experiment, PID controller (closed- loop)is used to arrange the damp characteristic.The experiment result shows thatwhen using push recovery control strategy (closed-loop control) is about 85.71% whilewithout using push recovery control strategy (open-loop control) it is about 28.57%.

On-Line Control of Glucose Concentration in High-Yielding Mammalian Cell Cultures Enabled Through Oxygen Transfer Rate Measurements.

PubMed

Goldrick, Stephen; Lee, Kenneth; Spencer, Christopher; Holmes, William; Kuiper, Marcel; Turner, Richard; Farid, Suzanne S

2018-04-01

Glucose control is vital to ensure consistent growth and protein production in mammalian cell cultures. The typical fed-batch glucose control strategy involving bolus glucose additions based on infrequent off-line daily samples results in cells experiencing significant glucose concentration fluctuations that can influence product quality and growth. This study proposes an on-line method to control and manipulate glucose utilizing readily available process measurements. The method generates a correlation between the cumulative oxygen transfer rate and the cumulative glucose consumed. This correlation generates an on-line prediction of glucose that has been successfully incorporated into a control algorithm manipulating the glucose feed-rate. This advanced process control (APC) strategy enables the glucose concentration to be maintained at an adjustable set-point and has been found to significantly reduce the deviation in glucose concentration in comparison to conventional operation. This method has been validated to produce various therapeutic proteins across cell lines with different glucose consumption demands and is successfully demonstrated on micro (15 mL), laboratory (7 L), and pilot (50 L) scale systems. This novel APC strategy is simple to implement and offers the potential to significantly enhance the glucose control strategy for scales spanning micro-scale systems through to full scale industrial bioreactors. © 2018 The Authors. Biotechnology Journal Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Atrial Fibrillation Management Strategies in Routine Clinical Practice: Insights from the International RealiseAF Survey

PubMed Central

Chiang, Chern-En; Naditch-Brûlé, Lisa; Brette, Sandrine; Silva-Cardoso, José; Gamra, Habib; Murin, Jan; Zharinov, Oleg J.; Steg, Philippe Gabriel

2016-01-01

Background Atrial fibrillation (AF) can be managed with rhythm- or rate-control strategies. There are few data from routine clinical practice on the frequency with which each strategy is used and their correlates in terms of patients’ clinical characteristics, AF control, and symptom burden. Methods RealiseAF was an international, cross-sectional, observational survey of 11,198 patients with AF. The aim of this analysis was to describe patient profiles and symptoms according to the AF management strategy used. A multivariate logistic regression identified factors associated with AF management strategy at the end of the visit. Results Among 10,497 eligible patients, 53.7% used a rate-control strategy, compared with 34.5% who used a rhythm-control strategy. In 11.8% of patients, no clear strategy was stated. The proportion of patients with AF-related symptoms (EHRA Class > = II) was 78.1% (n = 4396/5630) for those using a rate-control strategy vs. 67.8% for those using a rhythm-control strategy (p<0.001). Multivariate logistic regression analysis revealed that age <75 years or the paroxysmal or persistent form of AF favored the choice of a rhythm-control strategy. A change in strategy was infrequent, even in patients with European Heart Rhythm Association (EHRA) Class > = II. Conclusions In the RealiseAF routine clinical practice survey, rate control was more commonly used than rhythm control, and a change in strategy was uncommon, even in symptomatic patients. In almost 12% of patients, no clear strategy was stated. Physician awareness regarding optimal management strategies for AF may be improved. PMID:26800084

Children's Acquisition and Use of the Control-of-Variables Strategy: Effects of Explicit and Implicit Instructional Guidance

ERIC Educational Resources Information Center

Lazonder, Ard W.; Egberink, Angelique

2014-01-01

Direct instruction is a proven effective method to strengthen children's ability to design unconfounded experiments using the control-of-variables strategy (CVS). Recent research suggests that task segmentation can also promote children's use of this strategy. The present study investigated this assumption by comparing the relative…

Cognitive emotion regulation strategies in patients with functional dyspepsia and healthy controls - A comparative study

PubMed Central

Mazaheri, Mina; Afshar, Hamid; Nikneshan, Shekoufeh; Adibi, Peyman

2016-01-01

Background: Patients with functional dyspepsia (FD) may use specific coping strategies. Hence, the aim of the present study was to compare cognitive emotion regulation strategies in FD patients and healthy controls. Materials and Methods: This was a descriptive observational study. The sample consisted of 86 individuals, 43 of whom were patients diagnosed with FD. The patients referred to the psychosomatic disorders clinic, Isfahan, Iran. The comparative sample included 43 healthy controls (without digestive diagnoses) matched with the patients by age and gender. Subjects completed data on demographic factors and cognitive emotion regulation questionnaire. Results: The results indicated that there are significant differences between patients with FD and healthy controls according to using cognitive strategies. Scores of healthy controls in positive reappraisal and acceptance were significantly more than FD patients, and inversely, scores of FD patients in rumination and other-blame were meaningfully more than healthy controls. Conclusion: FD patients apply less adaptive strategies and more maladaptive strategies. It is seemed psychological interventions that focus on reducing maladaptive strategies and increasing adaptive strategies could be effective for FD patients. PMID:28217634

On the magnetic attitude control for spacecraft via the ɛ-strategies method

NASA Astrophysics Data System (ADS)

Smirnov, Georgi V.; Ovchinnikov, Mikhail; Miranda, Francisco

2008-09-01

We develop a new approach to stabilization problems based on a combination of the Lyapunov functions method with local controllability properties. The stabilizability is understood in the sense of ɛ-strategies introduced by Pontryagin in the frame of differential games theory. To illustrate the possibilities of our approach we consider a satellite with two magnetic coils directed along its principal inertia axes. Its circular orbit is neither polar nor equatorial. We show that there exists an ɛ-strategy stabilizing an Earth pointing satellite, whenever the deviations from the equilibrium position are small enough.

Effects of iterative learning based signal control strategies on macroscopic fundamental diagrams of urban road networks

NASA Astrophysics Data System (ADS)

Yan, Fei; Tian, Fuli; Shi, Zhongke

2016-10-01

Urban traffic flows are inherently repeated on a daily or weekly basis. This repeatability can help improve the traffic conditions if it is used properly by the control system. In this paper, we propose a novel iterative learning control (ILC) strategy for traffic signals of urban road networks using the repeatability feature of traffic flow. To improve the control robustness, the ILC strategy is further integrated with an error feedback control law in a complementary manner. Theoretical analysis indicates that the ILC-based traffic signal control methods can guarantee the asymptotic learning convergence, despite the presence of modeling uncertainties and exogenous disturbances. Finally, the impacts of the ILC-based signal control strategies on the network macroscopic fundamental diagram (MFD) are examined. The results show that the proposed ILC-based control strategies can homogenously distribute the network accumulation by controlling the vehicle numbers in each link to the desired levels under different traffic demands, which can result in the network with high capacity and mobility.

[Effect of schistosomiasis control strategy based on infection source control of Poyang Lake region in Yongxiu County promotion zone].

PubMed

Chen, Zhe; Rao, Xian-long; Li, Yi-feng; Gu, Xiao-nan; Xu, Mei-xin; Lin, Dan-dan

2015-12-01

To evaluate the effect of schistosomiasis control strategy with emphasis on infection source control in the Yongxiu County promotion zone of Poyang Lake region. The Wucheng Township of Yongxiu County was selected as the observation site, and the effect of the comprehensive control strategy was evaluated by using the method of field surveys combined with retrospective investigations. In 2010, there were 17 persons whose stool tests for schistosome infection were positive, and the number of calculated schistosomiasis patients was 2,331. The infection rate of cattle was 4.5%, and the area with infected Oncomelania hupensis snails was 10.00 hm². In 2011, the comprehensive control strategy was carried out, and in 2012, there were no cattle in the promotion zone. In 2013 and 2014, there were no schistosomiasis patients with positive stool tests. In 2014, no schistosome infected snails were found. The control strategy with emphasis on infection source control effectively controls the transmission of schistosomiasis in Yongxiu County promotion zone.

RNAi-based strategy for Asian citrus psyllid (Diaphorina citri) Control: A method to reduce the spread of citrus greening disease

USDA-ARS?s Scientific Manuscript database

Citrus greening disease is a serious bacterial disease of citrus worldwide and is vectored by the Asian citrus pysllid (Diaphorina Citri). The only effective control strategy includes vigorous control of the psyllid, primarily through heavy reliance on pesticides. As a more sustainable and environm...

WWC Review of the Report "Learning the Control of Variables Strategy in Higher and Lower Achieving Classrooms: Contributions of Explicit Instruction and Experimentation"

ERIC Educational Resources Information Center

What Works Clearinghouse, 2012

2012-01-01

The study reviewed in this paper examined three separate methods for teaching the "control of variables strategy" ("CVS"), a procedure for conducting a science experiment so that only one variable is tested and all others are held constant, or "controlled." The study analyzed data from a randomized controlled trial of…

Connection adaption for control of networked mobile chaotic agents.

PubMed

Zhou, Jie; Zou, Yong; Guan, Shuguang; Liu, Zonghua; Xiao, Gaoxi; Boccaletti, S

2017-11-22

In this paper, we propose a strategy for the control of mobile chaotic oscillators by adaptively rewiring connections between nearby agents with local information. In contrast to the dominant adaptive control schemes where coupling strength is adjusted continuously according to the states of the oscillators, our method does not request adaption of coupling strength. As the resulting interaction structure generated by this proposed strategy is strongly related to unidirectional chains, by investigating synchronization property of unidirectional chains, we reveal that there exists a certain coupling range in which the agents could be controlled regardless of the length of the chain. This feature enables the adaptive strategy to control the mobile oscillators regardless of their moving speed. Compared with existing adaptive control strategies for networked mobile agents, our proposed strategy is simpler for implementation where the resulting interaction networks are kept unweighted at all time.

Capacity value of energy storage considering control strategies

PubMed Central

Luo, Yi

2017-01-01

In power systems, energy storage effectively improves the reliability of the system and smooths out the fluctuations of intermittent energy. However, the installed capacity value of energy storage cannot effectively measure the contribution of energy storage to the generator adequacy of power systems. To achieve a variety of purposes, several control strategies may be utilized in energy storage systems. The purpose of this paper is to study the influence of different energy storage control strategies on the generation adequacy. This paper presents the capacity value of energy storage to quantitatively estimate the contribution of energy storage on the generation adequacy. Four different control strategies are considered in the experimental method to study the capacity value of energy storage. Finally, the analysis of the influence factors on the capacity value under different control strategies is given. PMID:28558027

Application of capability indices and control charts in the analytical method control strategy.

PubMed

Oliva, Alexis; Llabres Martinez, Matías

2017-08-01

In this study, we assessed the usefulness of control charts in combination with the process capability indices, C pm and C pk , in the control strategy of an analytical method. The traditional X-chart and moving range chart were used to monitor the analytical method over a 2-year period. The results confirmed that the analytical method is in-control and stable. Different criteria were used to establish the specifications limits (i.e. analyst requirements) for fixed method performance (i.e. method requirements). If the specification limits and control limits are equal in breadth, the method can be considered "capable" (C pm  = 1), but it does not satisfy the minimum method capability requirements proposed by Pearn and Shu (2003). Similar results were obtained using the C pk index. The method capability was also assessed as a function of method performance for fixed analyst requirements. The results indicate that the method does not meet the requirements of the analytical target approach. A real-example data of a SEC with light-scattering detection method was used as a model whereas previously published data were used to illustrate the applicability of the proposed approach. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

How do Air Traffic Controllers Use Automation and Tools Differently During High Demand Situations?

NASA Technical Reports Server (NTRS)

Kraut, Joshua M.; Mercer, Joey; Morey, Susan; Homola, Jeffrey; Gomez, Ashley; Prevot, Thomas

2013-01-01

In a human-in-the-loop simulation, two air traffic controllers managed identical airspace while burdened with higher than average workload, and while using advanced tools and automation designed to assist with scheduling aircraft on multiple arrival flows to a single meter fix. This paper compares the strategies employed by each controller, and investigates how the controllers' strategies change while managing their airspace under more normal workload conditions and a higher workload condition. Each controller engaged in different methods of maneuvering aircraft to arrive on schedule, and adapted their strategies to cope with the increased workload in different ways. Based on the conclusions three suggestions are made: that quickly providing air traffic controllers with recommendations and information to assist with maneuvering and scheduling aircraft when burdened with increased workload will improve the air traffic controller's effectiveness, that the tools should adapt to the strategy currently employed by a controller, and that training should emphasize which traffic management strategies are most effective given specific airspace demands.

[Aedes aegypti control strategies: a review].

PubMed

Zara, Ana Laura de Sene Amâncio; Santos, Sandra Maria Dos; Fernandes-Oliveira, Ellen Synthia; Carvalho, Roberta Gomes; Coelho, Giovanini Evelim

2016-01-01

to describe the main strategies to control Aedes aegypti, with emphasis on promising technological innovations for use in Brazil. this study is a non-systematic review of the literature. several technologies have been developed as alternatives in the control of Ae. aegypti, using different mechanisms of action, such as selective monitoring of the infestation, social interventions, dispersing insecticides, new biological control agents and molecular techniques for population control of mosquitoes, also considering the combination between them. Evolving technologies require evaluation of the effectiveness, feasibility and costs of implementation strategies as complementary to the actions already recommended by the National Program for Dengue Control. the integration of different compatible and effective vector control strategies, considering the available technologies and regional characteristics, appears to be a viable method to try to reduce the infestation of mosquitoes and the incidence of arbovirus transmitted by them.

Controller Strategies for Automation Tool Use under Varying Levels of Trajectory Prediction Uncertainty

NASA Technical Reports Server (NTRS)

Morey, Susan; Prevot, Thomas; Mercer, Joey; Martin, Lynne; Bienert, Nancy; Cabrall, Christopher; Hunt, Sarah; Homola, Jeffrey; Kraut, Joshua

2013-01-01

A human-in-the-loop simulation was conducted to examine the effects of varying levels of trajectory prediction uncertainty on air traffic controller workload and performance, as well as how strategies and the use of decision support tools change in response. This paper focuses on the strategies employed by two controllers from separate teams who worked in parallel but independently under identical conditions (airspace, arrival traffic, tools) with the goal of ensuring schedule conformance and safe separation for a dense arrival flow in en route airspace. Despite differences in strategy and methods, both controllers achieved high levels of schedule conformance and safe separation. Overall, results show that trajectory uncertainties introduced by wind and aircraft performance prediction errors do not affect the controllers' ability to manage traffic. Controller strategies were fairly robust to changes in error, though strategies were affected by the amount of delay to absorb (scheduled time of arrival minus estimated time of arrival). Using the results and observations, this paper proposes an ability to dynamically customize the display of information including delay time based on observed error to better accommodate different strategies and objectives.

40 CFR 52.1230 - Control strategy and rules: Particulates.

Code of Federal Regulations, 2013 CFR

2013-07-01

... PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Minnesota § 52.1230 Control strategy and rules: Particulates. (a) Part D—(1) Approval. The State of Minnesota has satisfied... alternative test method provision of Rule 7005.2910. (b) Approval—On May 31, 1988, the State of Minnesota...

40 CFR 52.1230 - Control strategy and rules: Particulates.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Minnesota § 52.1230 Control strategy and rules: Particulates. (a) Part D—(1) Approval. The State of Minnesota has satisfied... alternative test method provision of Rule 7005.2910. (b) Approval—On May 31, 1988, the State of Minnesota...

40 CFR 52.1230 - Control strategy and rules: Particulates.

Code of Federal Regulations, 2012 CFR

2012-07-01

... PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Minnesota § 52.1230 Control strategy and rules: Particulates. (a) Part D—(1) Approval. The State of Minnesota has satisfied... alternative test method provision of Rule 7005.2910. (b) Approval—On May 31, 1988, the State of Minnesota...

40 CFR 52.1230 - Control strategy and rules: Particulates.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Minnesota § 52.1230 Control strategy and rules: Particulates. (a) Part D—(1) Approval. The State of Minnesota has satisfied... alternative test method provision of Rule 7005.2910. (b) Approval—On May 31, 1988, the State of Minnesota...

OZONE AMBIENT AIR QUALITY STANDARD HAS BENEFICIAL EFFECT ON PONDEROSA PINE IN CALIFORNIA

EPA Science Inventory

Ambient air quality standards and control strategies are implemented to protect humans and vegetation from adverse effects. However, to date there has not been a simple and objective method to determine if the standards and resultant control strategies have reduced O3 impacts on ...

Decentralised control of continuous Petri nets

NASA Astrophysics Data System (ADS)

Wang, Liewei; Wang, Xu

2017-05-01

This paper focuses on decentralised control of systems modelled by continuous Petri nets, in which a target marking control problem is discussed. In some previous works, an efficient ON/OFF strategy-based minimum-time controller was developed. Nevertheless, the convergence is only proved for subclasses like Choice-Free nets. For a general net, the pre-conditions of applying the ON/OFF strategy are not given; therefore, the application scope of the method is unclear. In this work, we provide two sufficient conditions of applying the ON/OFF strategy-based controller to general nets. Furthermore, an extended algorithm for general nets is proposed, in which control laws are computed based on some limited information, without knowing the detailed structure of subsystems.

A new model predictive control algorithm by reducing the computing time of cost function minimization for NPC inverter in three-phase power grids.

PubMed

Taheri, Asghar; Zhalebaghi, Mohammad Hadi

2017-11-01

This paper presents a new control strategy based on finite-control-set model-predictive control (FCS-MPC) for Neutral-point-clamped (NPC) three-level converters. Containing some advantages like fast dynamic response, easy inclusion of constraints and simple control loop, makes the FCS-MPC method attractive to use as a switching strategy for converters. However, the large amount of required calculations is a problem in the widespread of this method. In this way, to resolve this problem this paper presents a modified method that effectively reduces the computation load compare with conventional FCS-MPC method and at the same time does not affect on control performance. The proposed method can be used for exchanging power between electrical grid and DC resources by providing active and reactive power compensations. Experiments on three-level converter for three Power Factor Correction (PFC), inductive and capacitive compensation modes verify the good and comparable performance. The results have been simulated using MATLAB/SIMULINK software. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Control method for turbocharged diesel engines having exhaust gas recirculation

DOEpatents

Kolmanovsky, Ilya V.; Jankovic, Mrdjan J; Jankovic, Miroslava

2000-03-14

A method of controlling the airflow into a compression ignition engine having an EGR and a VGT. The control strategy includes the steps of generating desired EGR and VGT turbine mass flow rates as a function of the desired and measured compressor mass airflow values and exhaust manifold pressure values. The desired compressor mass airflow and exhaust manifold pressure values are generated as a function of the operator-requested fueling rate and engine speed. The EGR and VGT turbine mass flow rates are then inverted to corresponding EGR and VGT actuator positions to achieve the desired compressor mass airflow rate and exhaust manifold pressure. The control strategy also includes a method of estimating the intake manifold pressure used in generating the EGR valve and VGT turbine positions.

Optimal intervention strategies for cholera outbreak by education and chlorination

NASA Astrophysics Data System (ADS)

Bakhtiar, Toni

2016-01-01

This paper discusses the control of infectious diseases in the framework of optimal control approach. A case study on cholera control was studied by considering two control strategies, namely education and chlorination. We distinct the former control into one regarding person-to-person behaviour and another one concerning person-to-environment conduct. Model are divided into two interacted populations: human population which follows an SIR model and pathogen population. Pontryagin maximum principle was applied in deriving a set of differential equations which consists of dynamical and adjoin systems as optimality conditions. Then, the fourth order Runge-Kutta method was exploited to numerically solve the equation system. An illustrative example was provided to assess the effectiveness of the control strategies toward a set of control scenarios.

Meta-analysis of studies on chemical, physical and biological agents in the control of Aedes aegypti.

PubMed

Lima, Estelita Pereira; Goulart, Marília Oliveira Fonseca; Rolim Neto, Modesto Leite

2015-09-04

Aedes aegypti is a vector of international concern because it can transmit to humans three important arboviral diseases: yellow fever, dengue and chikungunya. Epidemics that are repeated year after year in a variety of urban centers indicate that there are control failures, allowing the vector to continue expanding. To identify the most effective vector control strategies and the factors that contributed to the success or failure of each strategy, we carried out a systematic review with meta-analysis of articles published in 12 databases, from 1974 to the month of December 2013. We evaluated the association between the use of whatever chemical substance, mechanical agent, biological or integrated actions against A. aegypti and the control of the vector, as measured by 10 indicators. We found 2,791 articles, but after careful selection, only 26 studies remained for analysis related to control interventions implemented in 15 countries, with 5 biological, 5 chemical, 3 mechanical and 13 integrated strategies. The comparison among all of them, indicated that the control of A. aegypti is significantly associated with the type of strategy used, and that integrated interventions consist of the most effective method for controlling A. aegypti. The most effective control method was the integrated approach, considering the influence of eco-bio-social determinants in the virus-vector-man epidemiological chain, and community involvement, starting with community empowerment as active agents of vector control.

Strategies to diagnose and control microbial souring in natural gas storage reservoirs and produced water systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morris, E.A.; Derr, R.M.; Pope, D.H.

1995-12-31

Hydrogen sulfide production (souring) in natural gas storage reservoirs and produced water systems is a safety and environmental problem that can lead to operational shutdown when local hydrogen sulfide standards are exceeded. Systems affected by microbial souring have historically been treated using biocides that target the general microbial community. However, requirements for more environmentally friendly solutions have led to treatment strategies in which sulfide production can be controlled with minimal impact to the system and environment. Some of these strategies are based on microbial and/or nutritional augmentation of the sour environment. Through research sponsored by the Gas Research Institute (GRI)more » in Chicago, Illinois, methods have been developed for early detection of microbial souring in natural gas storage reservoirs, and a variety of mitigation strategies have been evaluated. The effectiveness of traditional biocide treatment in gas storage reservoirs was shown to depend heavily on the methods by which the chemical is applied. An innovative strategy using nitrate was tested and proved ideal for produced water and wastewater systems. Another strategy using elemental iodine was effective for sulfide control in evaporation ponds and is currently being tested in microbially sour natural gas storage wells.« less

Optimal robust control strategy of a solid oxide fuel cell system

NASA Astrophysics Data System (ADS)

Wu, Xiaojuan; Gao, Danhui

2018-01-01

Optimal control can ensure system safe operation with a high efficiency. However, only a few papers discuss optimal control strategies for solid oxide fuel cell (SOFC) systems. Moreover, the existed methods ignore the impact of parameter uncertainty on system instantaneous performance. In real SOFC systems, several parameters may vary with the variation of operation conditions and can not be identified exactly, such as load current. Therefore, a robust optimal control strategy is proposed, which involves three parts: a SOFC model with parameter uncertainty, a robust optimizer and robust controllers. During the model building process, boundaries of the uncertain parameter are extracted based on Monte Carlo algorithm. To achieve the maximum efficiency, a two-space particle swarm optimization approach is employed to obtain optimal operating points, which are used as the set points of the controllers. To ensure the SOFC safe operation, two feed-forward controllers and a higher-order robust sliding mode controller are presented to control fuel utilization ratio, air excess ratio and stack temperature afterwards. The results show the proposed optimal robust control method can maintain the SOFC system safe operation with a maximum efficiency under load and uncertainty variations.

Reactive power and voltage control strategy based on dynamic and adaptive segment for DG inverter

NASA Astrophysics Data System (ADS)

Zhai, Jianwei; Lin, Xiaoming; Zhang, Yongjun

2018-03-01

The inverter of distributed generation (DG) can support reactive power to help solve the problem of out-of-limit voltage in active distribution network (ADN). Therefore, a reactive voltage control strategy based on dynamic and adaptive segment for DG inverter is put forward to actively control voltage in this paper. The proposed strategy adjusts the segmented voltage threshold of Q(U) droop curve dynamically and adaptively according to the voltage of grid-connected point and the power direction of adjacent downstream line. And then the reactive power reference of DG inverter can be got through modified Q(U) control strategy. The reactive power of inverter is controlled to trace the reference value. The proposed control strategy can not only control the local voltage of grid-connected point but also help to maintain voltage within qualified range considering the terminal voltage of distribution feeder and the reactive support for adjacent downstream DG. The scheme using the proposed strategy is compared with the scheme without the reactive support of DG inverter and the scheme using the Q(U) control strategy with constant segmented voltage threshold. The simulation results suggest that the proposed method has a significant improvement on solving the problem of out-of-limit voltage, restraining voltage variation and improving voltage quality.

Robust backstepping control of an interlink converter in a hybrid AC/DC microgrid based on feedback linearisation method

NASA Astrophysics Data System (ADS)

Dehkordi, N. Mahdian; Sadati, N.; Hamzeh, M.

2017-09-01

This paper presents a robust dc-link voltage as well as a current control strategy for a bidirectional interlink converter (BIC) in a hybrid ac/dc microgrid. To enhance the dc-bus voltage control, conventional methods strive to measure and feedforward the load or source power in the dc-bus control scheme. However, the conventional feedforward-based approaches require remote measurement with communications. Moreover, conventional methods suffer from stability and performance issues, mainly due to the use of the small-signal-based control design method. To overcome these issues, in this paper, the power from DG units of the dc subgrid imposed on the BIC is considered an unmeasurable disturbance signal. In the proposed method, in contrast to existing methods, using the nonlinear model of BIC, a robust controller that does not need the remote measurement with communications effectively rejects the impact of the disturbance signal imposed on the BIC's dc-link voltage. To avoid communication links, the robust controller has a plug-and-play feature that makes it possible to add a DG/load to or remove it from the dc subgrid without distorting the hybrid microgrid stability. Finally, Monte Carlo simulations are conducted to confirm the effectiveness of the proposed control strategy in MATLAB/SimPowerSystems software environment.

A novel strategy with standardized reference extract qualification and single compound quantitative evaluation for quality control of Panax notoginseng used as a functional food.

PubMed

Li, S P; Qiao, C F; Chen, Y W; Zhao, J; Cui, X M; Zhang, Q W; Liu, X M; Hu, D J

2013-10-25

Root of Panax notoginseng (Burk.) F.H. Chen (Sanqi in Chinese) is one of traditional Chinese medicines (TCMs) based functional food. Saponins are the major bioactive components. The shortage of reference compounds or chemical standards is one of the main bottlenecks for quality control of TCMs. A novel strategy, i.e. standardized reference extract based qualification and single calibrated components directly quantitative estimation of multiple analytes, was proposed to easily and effectively control the quality of natural functional foods such as Sanqi. The feasibility and credibility of this methodology were also assessed with a developed fast HPLC method. Five saponins, including ginsenoside Rg1, Re, Rb1, Rd and notoginsenoside R1 were rapidly separated using a conventional HPLC in 20 min. The quantification method was also compared with individual calibration curve method. The strategy is feasible and credible, which is easily and effectively adapted for improving the quality control of natural functional foods such as Sanqi. Copyright © 2013 Elsevier B.V. All rights reserved.

A Course in... Multivariable Control Methods.

ERIC Educational Resources Information Center

Deshpande, Pradeep B.

1988-01-01

Describes an engineering course for graduate study in process control. Lists four major topics: interaction analysis, multiloop controller design, decoupling, and multivariable control strategies. Suggests a course outline and gives information about each topic. (MVL)

Neural networks for feedback feedforward nonlinear control systems.

PubMed

Parisini, T; Zoppoli, R

1994-01-01

This paper deals with the problem of designing feedback feedforward control strategies to drive the state of a dynamic system (in general, nonlinear) so as to track any desired trajectory joining the points of given compact sets, while minimizing a certain cost function (in general, nonquadratic). Due to the generality of the problem, conventional methods are difficult to apply. Thus, an approximate solution is sought by constraining control strategies to take on the structure of multilayer feedforward neural networks. After discussing the approximation properties of neural control strategies, a particular neural architecture is presented, which is based on what has been called the "linear-structure preserving principle". The original functional problem is then reduced to a nonlinear programming one, and backpropagation is applied to derive the optimal values of the synaptic weights. Recursive equations to compute the gradient components are presented, which generalize the classical adjoint system equations of N-stage optimal control theory. Simulation results related to nonlinear nonquadratic problems show the effectiveness of the proposed method.

The Linear Quadratic Gaussian Multistage Game with Nonclassical Information Pattern Using a Direct Solution Method

NASA Astrophysics Data System (ADS)

Clemens, Joshua William

Game theory has application across multiple fields, spanning from economic strategy to optimal control of an aircraft and missile on an intercept trajectory. The idea of game theory is fascinating in that we can actually mathematically model real-world scenarios and determine optimal decision making. It may not always be easy to mathematically model certain real-world scenarios, nonetheless, game theory gives us an appreciation for the complexity involved in decision making. This complexity is especially apparent when the players involved have access to different information upon which to base their decision making (a nonclassical information pattern). Here we will focus on the class of adversarial two-player games (sometimes referred to as pursuit-evasion games) with nonclassical information pattern. We present a two-sided (simultaneous) optimization solution method for the two-player linear quadratic Gaussian (LQG) multistage game. This direct solution method allows for further interpretation of each player's decision making (strategy) as compared to previously used formal solution methods. In addition to the optimal control strategies, we present a saddle point proof and we derive an expression for the optimal performance index value. We provide some numerical results in order to further interpret the optimal control strategies and to highlight real-world application of this game-theoretic optimal solution.

Adaptive backstepping sliding mode control with fuzzy monitoring strategy for a kind of mechanical system.

PubMed

Song, Zhankui; Sun, Kaibiao

2014-01-01

A novel adaptive backstepping sliding mode control (ABSMC) law with fuzzy monitoring strategy is proposed for the tracking-control of a kind of nonlinear mechanical system. The proposed ABSMC scheme combining the sliding mode control and backstepping technique ensure that the occurrence of the sliding motion in finite-time and the trajectory of tracking-error converge to equilibrium point. To obtain a better perturbation rejection property, an adaptive control law is employed to compensate the lumped perturbation. Furthermore, we introduce fuzzy monitoring strategy to improve adaptive capacity and soften the control signal. The convergence and stability of the proposed control scheme are proved by using Lyaponov's method. Finally, numerical simulations demonstrate the effectiveness of the proposed control scheme. © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

A three-level support method for smooth switching of the micro-grid operation model

NASA Astrophysics Data System (ADS)

Zong, Yuanyang; Gong, Dongliang; Zhang, Jianzhou; Liu, Bin; Wang, Yun

2018-01-01

Smooth switching of micro-grid between the grid-connected operation mode and off-grid operation mode is one of the key technologies to ensure it runs flexible and efficiently. The basic control strategy and the switching principle of micro-grid are analyzed in this paper. The reasons for the fluctuations of the voltage and the frequency in the switching process are analyzed from views of power balance and control strategy, and the operation mode switching strategy has been improved targeted. From the three aspects of controller’s current inner loop reference signal, voltage outer loop control strategy optimization and micro-grid energy balance management, a three-level security strategy for smooth switching of micro-grid operation mode is proposed. From the three aspects of controller’s current inner loop reference signal tracking, voltage outer loop control strategy optimization and micro-grid energy balance management, a three-level strategy for smooth switching of micro-grid operation mode is proposed. At last, it is proved by simulation that the proposed control strategy can make the switching process smooth and stable, the fluctuation problem of the voltage and frequency has been effectively improved.

Availability Control for Means of Transport in Decisive Semi-Markov Models of Exploitation Process

NASA Astrophysics Data System (ADS)

Migawa, Klaudiusz

2012-12-01

The issues presented in this research paper refer to problems connected with the control process for exploitation implemented in the complex systems of exploitation for technical objects. The article presents the description of the method concerning the control availability for technical objects (means of transport) on the basis of the mathematical model of the exploitation process with the implementation of the decisive processes by semi-Markov. The presented method means focused on the preparing the decisive for the exploitation process for technical objects (semi-Markov model) and after that specifying the best control strategy (optimal strategy) from among possible decisive variants in accordance with the approved criterion (criteria) of the activity evaluation of the system of exploitation for technical objects. In the presented method specifying the optimal strategy for control availability in the technical objects means a choice of a sequence of control decisions made in individual states of modelled exploitation process for which the function being a criterion of evaluation reaches the extreme value. In order to choose the optimal control strategy the implementation of the genetic algorithm was chosen. The opinions were presented on the example of the exploitation process of the means of transport implemented in the real system of the bus municipal transport. The model of the exploitation process for the means of transports was prepared on the basis of the results implemented in the real transport system. The mathematical model of the exploitation process was built taking into consideration the fact that the model of the process constitutes the homogenous semi-Markov process.

Analysis of a predator-prey model with Holling II functional response concerning impulsive control strategy

NASA Astrophysics Data System (ADS)

Liu, Bing; Teng, Zhidong; Chen, Lansun

2006-08-01

According to biological and chemical control strategy for pest control, we investigate the dynamic behavior of a Holling II functional response predator-prey system concerning impulsive control strategy-periodic releasing natural enemies and spraying pesticide at different fixed times. By using Floquet theorem and small amplitude perturbation method, we prove that there exists a stable pest-eradication periodic solution when the impulsive period is less than some critical value. Further, the condition for the permanence of the system is also given. Numerical results show that the system we consider can take on various kinds of periodic fluctuations and several types of attractor coexistence and is dominated by periodic, quasiperiodic and chaotic solutions, which implies that the presence of pulses makes the dynamic behavior more complex. Finally, we conclude that our impulsive control strategy is more effective than the classical one if we take chemical control efficiently.

Brain limbic system-based intelligent controller application to lane change manoeuvre

NASA Astrophysics Data System (ADS)

Kim, Changwon; Langari, Reza

2011-12-01

This paper presents the application of a novel neuromorphic control strategy for lane change manoeuvres in the highway environment. The lateral dynamics of a vehicle with and without wind disturbance are derived and utilised to implement a control strategy based on the brain limbic system. To show the robustness of the proposed controller, several disturbance conditions including wind, uncertainty in the cornering stiffness, and changes in the vehicle mass are investigated. To demonstrate the performance of the suggested strategy, simulation results of the proposed method are compared with the human driver model-based control scheme, which has been discussed in the literature. The simulation results demonstrate the superiority of the proposed controller in energy efficiency, driving comfort, and robustness.

Method and apparatus for adaptive force and position control of manipulators

NASA Technical Reports Server (NTRS)

Seraji, Homayoun (Inventor)

1995-01-01

The described and improved multi-arm invention of this application presents three strategies for adaptive control of cooperative multi-arm robots which coordinate control over a common load. In the position-position control strategy, the adaptive controllers ensure that the end-effector positions of both arms track desired trajectories in Cartesian space despite unknown time-varying interaction forces exerted through a load. In the position-hybrid control strategy, the adaptive controller of one arm controls end-effector motions in the free directions and applied forces in the constraint directions; while the adaptive controller of the other arm ensures that the end-effector tracks desired position trajectories. In the hybrid-hybrid control strategy, the adaptive controllers ensure that both end-effectors track reference position trajectories while simultaneously applying desired forces on the load. In all three control strategies, the cross-coupling effects between the arms are treated as disturbances which are compensated for by the adaptive controllers while following desired commands in a common frame of reference. The adaptive controllers do not require the complex mathematical model of the arm dynamics or any knowledge of the arm dynamic parameters or the load parameters such as mass and stiffness. Circuits in the adaptive feedback and feedforward controllers are varied by novel adaptation laws.

Biological Control of Mosquito Vectors: Past, Present, and Future

PubMed Central

Benelli, Giovanni; Jeffries, Claire L.; Walker, Thomas

2016-01-01

Mosquitoes represent the major arthropod vectors of human disease worldwide transmitting malaria, lymphatic filariasis, and arboviruses such as dengue virus and Zika virus. Unfortunately, no treatment (in the form of vaccines or drugs) is available for most of these diseases and vector control is still the main form of prevention. The limitations of traditional insecticide-based strategies, particularly the development of insecticide resistance, have resulted in significant efforts to develop alternative eco-friendly methods. Biocontrol strategies aim to be sustainable and target a range of different mosquito species to reduce the current reliance on insecticide-based mosquito control. In this review, we outline non-insecticide based strategies that have been implemented or are currently being tested. We also highlight the use of mosquito behavioural knowledge that can be exploited for control strategies. PMID:27706105

An Interactive Computer-Aided Instructional Strategy and Assessment Methods for System Identification and Adaptive Control Laboratory

ERIC Educational Resources Information Center

Özbek, Necdet Sinan; Eker, Ilyas

2015-01-01

This study describes a set of real-time interactive experiments that address system identification and model reference adaptive control (MRAC) techniques. In constructing laboratory experiments that contribute to efficient teaching, experimental design and instructional strategy are crucial, but a process for doing this has yet to be defined. This…

A Lyapunov based approach to energy maximization in renewable energy technologies

NASA Astrophysics Data System (ADS)

Iyasere, Erhun

This dissertation describes the design and implementation of Lyapunov-based control strategies for the maximization of the power captured by renewable energy harnessing technologies such as (i) a variable speed, variable pitch wind turbine, (ii) a variable speed wind turbine coupled to a doubly fed induction generator, and (iii) a solar power generating system charging a constant voltage battery. First, a torque control strategy is presented to maximize wind energy captured in variable speed, variable pitch wind turbines at low to medium wind speeds. The proposed strategy applies control torque to the wind turbine pitch and rotor subsystems to simultaneously control the blade pitch and tip speed ratio, via the rotor angular speed, to an optimum point at which the capture efficiency is maximum. The control method allows for aerodynamic rotor power maximization without exact knowledge of the wind turbine model. A series of numerical results show that the wind turbine can be controlled to achieve maximum energy capture. Next, a control strategy is proposed to maximize the wind energy captured in a variable speed wind turbine, with an internal induction generator, at low to medium wind speeds. The proposed strategy controls the tip speed ratio, via the rotor angular speed, to an optimum point at which the efficiency constant (or power coefficient) is maximal for a particular blade pitch angle and wind speed by using the generator rotor voltage as a control input. This control method allows for aerodynamic rotor power maximization without exact wind turbine model knowledge. Representative numerical results demonstrate that the wind turbine can be controlled to achieve near maximum energy capture. Finally, a power system consisting of a photovoltaic (PV) array panel, dc-to-dc switching converter, charging a battery is considered wherein the environmental conditions are time-varying. A backstepping PWM controller is developed to maximize the power of the solar generating system. The controller tracks a desired array voltage, designed online using an incremental conductance extremum-seeking algorithm, by varying the duty cycle of the switching converter. The stability of the control algorithm is demonstrated by means of Lyapunov analysis. Representative numerical results demonstrate that the grid power system can be controlled to track the maximum power point of the photovoltaic array panel in varying atmospheric conditions. Additionally, the performance of the proposed strategy is compared to the typical maximum power point tracking (MPPT) method of perturb and observe (P&O), where the converter dynamics are ignored, and is shown to yield better results.

System training and assessment in simultaneous proportional myoelectric prosthesis control

PubMed Central

2014-01-01

Background Pattern recognition control of prosthetic hands take inputs from one or more myoelectric sensors and controls one or more degrees of freedom. However, most systems created allow only sequential control of one motion class at a time. Additionally, only recently have researchers demonstrated proportional myoelectric control in such systems, an option that is believed to make fine control easier for the user. Recent developments suggest improved reliability if the user follows a so-called prosthesis guided training (PGT) scheme. Methods In this study, a system for simultaneous proportional myoelectric control has been developed for a hand prosthesis with two motor functions (hand open/close, and wrist pro-/supination). The prosthesis has been used with a prosthesis socket equivalent designed for normally-limbed subjects. An extended version of PGT was developed for use with proportional control. The control system’s performance was tested for two subjects in the Clothespin Relocation Task and the Southampton Hand Assessment Procedure (SHAP). Simultaneous proportional control was compared with three other control strategies implemented on the same prosthesis: mutex proportional control (the same system but with simultaneous control disabled), mutex on-off control, and a more traditional, sequential proportional control system with co-contractions for state switching. Results The practical tests indicate that the simultaneous proportional control strategy and the two mutex-based pattern recognition strategies performed equally well, and superiorly to the more traditional sequential strategy according to the chosen outcome measures. Conclusions This is the first simultaneous proportional myoelectric control system demonstrated on a prosthesis affixed to the forearm of a subject. The study illustrates that PGT is a promising system training method for proportional control. Due to the limited number of subjects in this study, no definite conclusions can be drawn. PMID:24775602

Analysis and decoupling control of a permanent magnet spherical actuator.

PubMed

Zhang, Liang; Chen, Weihai; Liu, Jingmeng; Wu, Xingming

2013-12-01

This paper presents the analysis and decoupling control of a spherical actuator, which is capable of performing three degree-of-freedom motion in one joint. The proposed actuator consists of a rotor with multiple PM (Permanent Magnet) poles in a circle and a stator with circumferential coils in three layers. Based on this actuator design, a decoupling control approach is developed. Unlike existing control methods that each coil is responsible for both the spinning and tilting motion, the proposed control strategy specifies the function of each coil. Specifically, the spinning motion is governed by the middle layer coils with a step control approach; while the tilting motion is regulated by upper and lower coils with a computed torque control method. Experiments have been conducted on the prototype to verify the validity of the design procedure, and the experimental results demonstrate the effectiveness of the analysis and control strategy.

[Fundamental strategies to address the problem of public health service delivery insufficiency of disease prevention and control system of China].

PubMed

Shao, Jing-jing; Yu, Jing-jin; Yu, Ming-zhu; Duan, Yong; Gong, Xiangguang; Chen, Zheng; Wang, Hua; Shi, Peiwu; Liang, Zhankai; Yang, Feng; Wang, Dunzhi; Yue, Jianning; Luo, Shi; Luo, Li; Wang, Weicheng; Wang, Ying; Sun, Mei; Su, Zhongxin; Ma, Ning; Xie, Hongbin; Hao, Mo

2005-03-01

To develop and demonstrate the strategies to solve the problem of public health service delivery insufficiency of disease prevention and control system of China. 205 literatures in 8 national academic journals concerning health service management have been reviewed. The method of boundary analysis has been employed to conclude the various reform strategies. Based on the causes and mechanism of public health service delivery insufficiency of disease prevention and control system, the logic analysis has been employed to develop fundamental strategies, which has been demonstrated by 154 CDC using intention questionnaires. There are fundamental strategies to which the agreeing rate for sampling CDC was over 95%: to make sure government should afford the financing function of disease prevention and control and secure the feasible investment for centers of disease prevention and control. Meanwhile, the working efficiency of CDC should be improved through strengthening management and reforming government investing manner.

Periodic-Zone Model Predictive Control for Diurnal Closed-Loop Operation of an Artificial Pancreas

PubMed Central

Gondhalekar, Ravi; Dassau, Eyal; Zisser, Howard C.; Doyle, Francis J.

2013-01-01

Background The objective of this research is an artificial pancreas (AP) that performs automatic regulation of blood glucose levels in people with type 1 diabetes mellitus. This article describes a control strategy that performs algorithmic insulin dosing for maintaining safe blood glucose levels over prolonged, overnight periods of time and furthermore was designed with outpatient, multiday deployment in mind. Of particular concern is the prevention of nocturnal hypoglycemia, because during sleep, subjects cannot monitor themselves and may not respond to alarms. An AP intended for prolonged and unsupervised outpatient deployment must strategically reduce the risk of hypoglycemia during times of sleep, without requiring user interaction. Methods A diurnal insulin delivery strategy based on predictive control methods is proposed. The so-called “periodic-zone model predictive control” (PZMPC) strategy employs periodically time-dependent blood glucose output target zones and furthermore enforces periodically time-dependent insulin input constraints to modulate its behavior based on the time of day. Results The proposed strategy was evaluated through an extensive simulation-based study and a preliminary clinical trial. Results indicate that the proposed method delivers insulin more conservatively during nighttime than during daytime while maintaining safe blood glucose levels at all times. In clinical trials, the proposed strategy delivered 77% of the amount of insulin delivered by a time-invariant control strategy; specifically, it delivered on average 1.23 U below, compared with 0.31 U above, the nominal basal rate overnight while maintaining comparable, and safe, blood glucose values. Conclusions The proposed PZMPC algorithm strategically prevents nocturnal hypoglycemia and is considered a significant step toward deploying APs into outpatient environments for extended periods of time in full closed-loop operation. PMID:24351171

Determining Students' Attitude towards Physics through Problem-Solving Strategy

ERIC Educational Resources Information Center

Erdemir, Naki

2009-01-01

In this study, the effects of teacher-directed and self-directed problem-solving strategies on students' attitudes toward physics were explored. Problem-solving strategies were used with the experimental group, while the control group was instructed using traditional teaching methods. The study was conducted with 270 students at various high…

Adult Professional Development: Can Brain-Based Teaching Strategies Increase Learning Effectiveness?

ERIC Educational Resources Information Center

Tilton, Wendy

2011-01-01

Brain-based teaching strategies, compared to facilitative student-centered teaching strategies, were employed with 62 real estate professionals in a quasi-mixed-methods study. Participants attended a 2-day proprietary real estate continuing education course. Both the experimental and control groups received the same facilitative instruction, as…

Control strategies for robots in contact

NASA Astrophysics Data System (ADS)

Park, Jaeheung

In the field of robotics, there is a growing need to provide robots with the ability to interact with complex and unstructured environments. Operations in such environments pose significant challenges in terms of sensing, planning, and control. In particular, it is critical to design control algorithms that account for the dynamics of the robot and environment at multiple contacts. The work in this thesis focuses on the development of a control framework that addresses these issues. The approaches are based on the operational space control framework and estimation methods. By accounting for the dynamics of the robot and environment, modular and systematic methods are developed for robots interacting with the environment at multiple locations. The proposed force control approach demonstrates high performance in the presence of uncertainties. Building on this basic capability, new control algorithms have been developed for haptic teleoperation, multi-contact interaction with the environment, and whole body motion of non-fixed based robots. These control strategies have been experimentally validated through simulations and implementations on physical robots. The results demonstrate the effectiveness of the new control structure and its robustness to uncertainties. The contact control strategies presented in this thesis are expected to contribute to the needs in advanced controller design for humanoid and other complex robots interacting with their environments.

Control strategies for systems with limited actuators

NASA Technical Reports Server (NTRS)

Marcopoli, Vincent R.; Phillips, Stephen M.

1994-01-01

This work investigates the effects of actuator saturation in multi-input, multi-output (MIMO) control systems. The adverse system behavior introduced by the saturation nonlinearity is viewed here as resulting from two mechanisms: controller windup - a problem caused by the discrepancy between the limited actuator commands and the corresponding control signals, and directionality - the problem of how to use nonlimited actuators when a limited condition exists. The tracking mode and Hanus methods are two common strategies for dealing with the windup problem. It is seen that while these methods alleviate windup, performance problems remain due to plant directionality. Though high gain conventional antiwindup as well as more general linear methods have the potential to address both windup and directionality, no systematic design method for these schemes has emerged; most approaches used in practice are application driven. An alternative method of addressing the directionality problem is presented which involves the introduction of a control direction preserving nonlinearity to the Hanus antiwindup system. A nonlinearity is subsequently proposed which reduces the conservation inherent in the former direction-preserving approach, improving performance. The concept of multivariable sensitivity is seen to play a key role in the success of the new method.

An Examination of Strategy Implementation During Abstract Nonlinguistic Category Learning in Aphasia

PubMed Central

Kiran, Swathi

2015-01-01

Purpose Our purpose was to study strategy use during nonlinguistic category learning in aphasia. Method Twelve control participants without aphasia and 53 participants with aphasia (PWA) completed a computerized feedback-based category learning task consisting of training and testing phases. Accuracy rates of categorization in testing phases were calculated. To evaluate strategy use, strategy analyses were conducted over training and testing phases. Participant data were compared with model data that simulated complex multi-cue, single feature, and random pattern strategies. Learning success and strategy use were evaluated within the context of standardized cognitive–linguistic assessments. Results Categorization accuracy was higher among control participants than among PWA. The majority of control participants implemented suboptimal or optimal multi-cue and single-feature strategies by testing phases of the experiment. In contrast, a large subgroup of PWA implemented random patterns, or no strategy, during both training and testing phases of the experiment. Conclusions Person-to-person variability arises not only in category learning ability but also in the strategies implemented to complete category learning tasks. PWA less frequently developed effective strategies during category learning tasks than control participants. Certain PWA may have impairments of strategy development or feedback processing not captured by language and currently probed cognitive abilities. PMID:25908438

Mathematical Critical Thinking and Curiosity Attitude in Problem Based Learning and Cognitive Conflict Strategy: A Study in Number Theory Course

ERIC Educational Resources Information Center

Zetriuslita; Wahyudin; Jarnawi

2017-01-01

This research aims to describe and analyze result of applying Problem-Based Learning and Cognitive Conflict Strategy (PBLCCS) in increasing students' Mathematical Critical Thinking (MCT) ability and Mathematical Curiosity Attitude (MCA). Adopting a quasi-experimental method with pretest-posttest control group design and using mixed method with…

Dynamic performance analysis of permanent magnet contactor with a flux-weakening control strategy

NASA Astrophysics Data System (ADS)

Wang, Xianbing; Lin, Heyun; Fang, Shuhua; Jin, Ping; Wang, Junhua; Ho, S. L.

2011-04-01

A new flux-weakening control strategy for permanent magnet contactors is proposed. By matching the dynamic attraction force and the antiforce, the terminal velocity and collision energy of the movable iron in the closing process are significantly reduced. The movable iron displacement is estimated by detecting the closing voltage and current with the proposed control. A dynamic mathematical model is also established under four kinds of excitation scenarios. The attraction force and flux linkage are predicted by finite element method and the dynamics of the closing process is simulated using the 4th-order Runge-Kutta algorithm. Experiments are carried out on a 250A prototype with an intelligent control unit to verify the proposed control strategy.

Attention Deficit Hyperactivity Disorder: Strategies for the Classroom.

ERIC Educational Resources Information Center

Purvis, Johnny R.; And Others

1992-01-01

This article discusses classroom strategies used with students with attention deficit hyperactivity disorder (ADHD), methods for controlling the ADHD child's behavior, and the need for consistency and collaboration between the school and home. (Author/JDD)

A community-based health education analysis of an infectous disease control program in Nigeria.

PubMed

Adeyanju, O M

1987-01-01

This descriptive study utilized the strategy of primary health care in program development-especially a community-based health education intervention approach-in the control of guinea-worm in rural communities of Nigeria. Two closely related rural communities in two states served as target groups. Committee system approach, nominal group process, interview methods, audio-visual aids, and health care volunteer trainingship were the educational strategies employed in a control and experimental set up. The PRECEDE model was applied in the analysis. Results show a significant control action on guinea-worm infestation in the experimental community and a tremendous achievement in preventive health education interventions through organized community participation/involvement and ultimate self-reliance and individual responsibility. A positive increase in health knowledge and attitude examined through interview method, and observable changes in health behavior were noticed. Wells were provided, drinking water treated, while personal and community health promotion strategies were encouraged by all. The study has shown the effectiveness/efficacy of a community-based effort facilitated by a health educator.

USER'S GUIDE: EMISSION CONTROL TECHNOLOGIES AND EMISSION FACTORS FOR UNPAVED ROAD FUGITIVE EMISSIONS

EPA Science Inventory

This document assists control agency personnel in evaluating unpaved road fugitive emissions control plans and helps industry personnel develop effective control strategies for unpaved roads. he brochure describes control techniques for reducing unpaved road emissions and methods...

Student-Generated Visualization as a Study Strategy for Science Concept Learning

ERIC Educational Resources Information Center

Hsieh, Yi-Chuan Jane; Cifuentes, Lauren

2006-01-01

Mixed methods were adopted to explore the effects of student-generated visualization on paper and on computers as a study strategy for middle school science concept learning. In a post-test-only-control-group design, scores were compared among a control-group (n=28), a group that was trained to visualize on paper (n=30), and a group that was…

Proactive control of proactive interference using the method of loci.

PubMed

Bass, Willa S; Oswald, Karl M

2014-01-01

Proactive interferencebuilds up with exposure to multiple lists of similar items with a resulting reduction in recall. This study examined the effectiveness of using a proactive strategy of the method of loci to reduce proactive interference in a list recall paradigm of categorically similar words. While all participants reported using some form of strategy to recall list words, this study demonstrated that young adults were able to proactively use the method of loci after 25 min of instruction to reduce proactive interference as compared with other personal spontaneous strategies. The implications of this study are that top-down proactive strategies such as the method of loci can significantly reduce proactive interference, and that the use of image and sequence or location are especially useful in this regard.

Proactive control of proactive interference using the method of loci

PubMed Central

Bass, Willa S.; Oswald, Karl M.

2014-01-01

Proactive interferencebuilds up with exposure to multiple lists of similar items with a resulting reduction in recall. This study examined the effectiveness of using a proactive strategy of the method of loci to reduce proactive interference in a list recall paradigm of categorically similar words. While all participants reported using some form of strategy to recall list words, this study demonstrated that young adults were able to proactively use the method of loci after 25 min of instruction to reduce proactive interference as compared with other personal spontaneous strategies. The implications of this study are that top-down proactive strategies such as the method of loci can significantly reduce proactive interference, and that the use of image and sequence or location are especially useful in this regard. PMID:25157300

Self-organizing control strategy for asteroid intelligent detection swarm based on attraction and repulsion

NASA Astrophysics Data System (ADS)

An, Meiyan; Wang, Zhaokui; Zhang, Yulin

2017-01-01

The self-organizing control strategy for asteroid intelligent detection swarm, which is considered as a space application instance of intelligent swarm, is developed. The leader-follower model for the asteroid intelligent detection swarm is established, and the further analysis is conducted for massive asteroid and small asteroid. For a massive asteroid, the leader spacecraft flies under the gravity field of the asteroid. For a small asteroid, the asteroid gravity is negligible, and a trajectory planning method is proposed based on elliptic cavity virtual potential field. The self-organizing control strategy for the follower spacecraft is developed based on a mechanism of velocity planning and velocity tracking. The simulation results show that the self-organizing control strategy is valid for both massive asteroid and small asteroid, and the exploration swarm forms a stable configuration.

The role of strategies in motor learning

PubMed Central

Taylor, Jordan A.; Ivry, Richard B.

2015-01-01

There has been renewed interest in the role of strategies in sensorimotor learning. The combination of new behavioral methods and computational methods has begun to unravel the interaction between processes related to strategic control and processes related to motor adaptation. These processes may operate on very different error signals. Strategy learning is sensitive to goal-based performance error. In contrast, adaptation is sensitive to prediction errors between the desired and actual consequences of a planned movement. The former guides what the desired movement should be, whereas the latter guides how to implement the desired movement. Whereas traditional approaches have favored serial models in which an initial strategy-based phase gives way to more automatized forms of control, it now seems that strategic and adaptive processes operate with considerable independence throughout learning, although the relative weight given the two processes will shift with changes in performance. As such, skill acquisition involves the synergistic engagement of strategic and adaptive processes. PMID:22329960

Online gaming for learning optimal team strategies in real time

NASA Astrophysics Data System (ADS)

Hudas, Gregory; Lewis, F. L.; Vamvoudakis, K. G.

2010-04-01

This paper first presents an overall view for dynamical decision-making in teams, both cooperative and competitive. Strategies for team decision problems, including optimal control, zero-sum 2-player games (H-infinity control) and so on are normally solved for off-line by solving associated matrix equations such as the Riccati equation. However, using that approach, players cannot change their objectives online in real time without calling for a completely new off-line solution for the new strategies. Therefore, in this paper we give a method for learning optimal team strategies online in real time as team dynamical play unfolds. In the linear quadratic regulator case, for instance, the method learns the Riccati equation solution online without ever solving the Riccati equation. This allows for truly dynamical team decisions where objective functions can change in real time and the system dynamics can be time-varying.

A novel optimal coordinated control strategy for the updated robot system for single port surgery.

PubMed

Bai, Weibang; Cao, Qixin; Leng, Chuntao; Cao, Yang; Fujie, Masakatsu G; Pan, Tiewen

2017-09-01

Research into robotic systems for single port surgery (SPS) has become widespread around the world in recent years. A new robot arm system for SPS was developed, but its positioning platform and other hardware components were not efficient. Special features of the developed surgical robot system make good teleoperation with safety and efficiency difficult. A robot arm is combined and used as new positioning platform, and the remote center motion is realized by a new method using active motion control. A new mapping strategy based on kinematics computation and a novel optimal coordinated control strategy based on real-time approaching to a defined anthropopathic criterion configuration that is referred to the customary ease state of human arms and especially the configuration of boxers' habitual preparation posture are developed. The hardware components, control architecture, control system, and mapping strategy of the robotic system has been updated. A novel optimal coordinated control strategy is proposed and tested. The new robot system can be more dexterous, intelligent, convenient and safer for preoperative positioning and intraoperative adjustment. The mapping strategy can achieve good following and representation for the slave manipulator arms. And the proposed novel control strategy can enable them to complete tasks with higher maneuverability, lower possibility of self-interference and singularity free while teleoperating. Copyright © 2017 John Wiley & Sons, Ltd.

The Effectiveness of Tutorial Strategies: An Experimental Evaluation.

ERIC Educational Resources Information Center

Swanson, Judy H.

The effectiveness of three tutorial strategies was evaluated by experimentally manipulating the strategies used in a 2 X 3 factorial design. Two tutors taught 48 college undergraduates a basic optics lesson about "how lenses work," using three instructional methods which varied the amount of tutor control. In the lecture condition, tutors assumed…

Assessment of combating-desertification strategies using the linear assignment method

NASA Astrophysics Data System (ADS)

Hassan Sadeghravesh, Mohammad; Khosravi, Hassan; Ghasemian, Soudeh

2016-04-01

Nowadays desertification, as a global problem, affects many countries in the world, especially developing countries like Iran. With respect to increasing importance of desertification and its complexity, the necessity of attention to the optimal combating-desertification alternatives is essential. Selecting appropriate strategies according to all effective criteria to combat the desertification process can be useful in rehabilitating degraded lands and avoiding degradation in vulnerable fields. This study provides systematic and optimal strategies of combating desertification by use of a group decision-making model. To this end, the preferences of indexes were obtained through using the Delphi model, within the framework of multi-attribute decision making (MADM). Then, priorities of strategies were evaluated by using linear assignment (LA) method. According to the results, the strategies to prevent improper change of land use (A18), development and reclamation of plant cover (A23), and control overcharging of groundwater resources (A31) were identified as the most important strategies for combating desertification in this study area. Therefore, it is suggested that the aforementioned ranking results be considered in projects which control and reduce the effects of desertification and rehabilitate degraded lands.

Semi Active Control of Civil Structures, Analytical and Numerical Studies

NASA Astrophysics Data System (ADS)

Kerboua, M.; Benguediab, M.; Megnounif, A.; Benrahou, K. H.; Kaoulala, F.

Structural control for civil structures was born out of a need to provide safer and more efficient designs with the reality of limited resources. The purpose of structural control is to absorb and to reflect the energy introduced by dynamic loads such as winds, waves, earthquakes, and traffic. Today, the protection of civil structures from severe dynamic loading is typically achieved by allowing the structures to be damaged. Semi-active control devices, also called "smart" control devices, assume the positive aspects of both the passive and active control devices. A semi-active control strategy is similar to the active control strategy. Only here, the control actuator does not directly apply force to the structure, but instead it is used to control the properties of a passive energy device, a controllable passive damper. Semi-active control strategies can be used in many of the same civil applications as passive and active control. One method of operating smart cable dampers is in a purely passive capacity, supplying the dampers with constant optimal voltage. The advantages to this strategy are the relative simplicity of implementing the control strategy as compared to a smart or active control strategy and that the dampers are more easily optimally tuned in- place, eliminating the need to have passive dampers with unique optimal damping coefficients. This research investigated semi-active control of civil structures for natural hazard mitigation. The research has two components, the seismic protection of buildings and the mitigation of wind-induced vibration in structures. An ideal semi-active motion equation of a composite beam that consists of a cantilever beam bonded with a PZT patch using Hamilton's principle and Galerkin's method was treated. A series R-L and a parallel R-L shunt circuits are coupled into the motion equation respectively by means of the constitutive relation of piezoelectric material and Kirchhoff's law to control the beam vibration. A numerical example of the parallel R-L piezoelectric vibration shunt control simulated with MATLAB® is presented. An analytical study of the resistor-inductor (R-L) passive piezoelectric vibration shunt control of a cantilever beam was undertaken. The modal and strain analyses were performed by varying the material properties and geometric configurations of the piezoelectric transducer in relation to the structure in order to maximize the mechanical strain produced in the piezoelectric transducer.

FAMACHA(©) method as an auxiliary strategy in the control of gastrointestinal helminthiasis of dairy goats under semiarid conditions of Northeastern Brazil.

PubMed

Vilela, Vinícius Longo Ribeiro; Feitosa, Thais Ferreira; Linhares, Emanuel Figueiredo; Athayde, Ana Célia Rodrigues; Molento, Marcelo Beltrão; Azevedo, Sérgio Santos

2012-11-23

This study aimed to evaluate the utilization of FAMACHA(©) method as an auxiliary strategy to use the individual identification for the selective control of gastrointestinal helminthiasis in naturally infected dairy goats. The experiment was conducted on 63 farms in the towns of Passagem, Quixabá and Cacimba de Areia, semiarid region of the Paraíba state, Brazil. Fifty animals were used on each farm, being visited tree farms per month, totaling 1800 animals, between May 2009 and April 2010. The animals received no anthelmintic treatment for at least four months prior to the farm visits. All animals were subjected to parasitological faecal collection, blood sampling for packed cell volume and the visual/selective exam of the eye colour through the FAMACHA(©) method. Larvae culture was performed in every assessment on each farm. Haemonchus sp. was the most prevalent helminth (80.1%) on larval cultures. The use of this method allowed a reduction of 79.2% on anthelmintic application in dairy goats. The FAMACHA(©) method proved to be a viable auxiliary strategy to control gastrointestinal helminthiasis of dairy goats from a resource-poor area in the semiarid region of the Paraíba state, Northeastern Brazil. Copyright © 2012 Elsevier B.V. All rights reserved.

Open-loop-feedback control of serum drug concentrations: pharmacokinetic approaches to drug therapy.

PubMed

Jelliffe, R W

1983-01-01

Recent developments to optimize open-loop-feedback control of drug dosage regimens, generally applicable to pharmacokinetically oriented therapy with many drugs, involve computation of patient-individualized strategies for obtaining desired serum drug concentrations. Analyses of past therapy are performed by least squares, extended least squares, and maximum a posteriori probability Bayesian methods of fitting pharmacokinetic models to serum level data. Future possibilities for truly optimal open-loop-feedback therapy with full Bayesian methods, and conceivably for optimal closed-loop therapy in such data-poor clinical situations, are also discussed. Implementation of these various therapeutic strategies, using automated, locally controlled infusion devices, has also been achieved in prototype form.

The Effect of Given Homework upon the Instruction of Self-Regulation Strategies That Were Directed to Develop Self-Regulation Strategies

ERIC Educational Resources Information Center

Eker, Cevat

2013-01-01

The aim of this study is to specify the effect of self-regulation strategies upon the instruction of secondary school 5th grade students, whom were given homework to do. In this research, pretest - posttest control group design of experimental method was used. Self-Regulation Learning Strategies Scale (SRLSS), the sub-dimension of the Motivated…

Opinion control in complex networks

NASA Astrophysics Data System (ADS)

Masuda, Naoki

2015-03-01

In many political elections, the electorate appears to be a composite of partisan and independent voters. Given that partisans are not likely to convert to a different party, an important goal for a political party could be to mobilize independent voters toward the party with the help of strong leadership, mass media, partisans, and the effects of peer-to-peer influence. Based on the exact solution of classical voter model dynamics in the presence of perfectly partisan voters (i.e., zealots), we propose a computational method that uses pinning control strategy to maximize the share of a party in a social network of independent voters. The party, corresponding to the controller or zealots, optimizes the nodes to be controlled given the information about the connectivity of independent voters and the set of nodes that the opposing party controls. We show that controlling hubs is generally a good strategy, but the optimized strategy is even better. The superiority of the optimized strategy is particularly eminent when the independent voters are connected as directed (rather than undirected) networks.

Nonlinear Adaptive PID Control for Greenhouse Environment Based on RBF Network

PubMed Central

Zeng, Songwei; Hu, Haigen; Xu, Lihong; Li, Guanghui

2012-01-01

This paper presents a hybrid control strategy, combining Radial Basis Function (RBF) network with conventional proportional, integral, and derivative (PID) controllers, for the greenhouse climate control. A model of nonlinear conservation laws of enthalpy and matter between numerous system variables affecting the greenhouse climate is formulated. RBF network is used to tune and identify all PID gain parameters online and adaptively. The presented Neuro-PID control scheme is validated through simulations of set-point tracking and disturbance rejection. We compare the proposed adaptive online tuning method with the offline tuning scheme that employs Genetic Algorithm (GA) to search the optimal gain parameters. The results show that the proposed strategy has good adaptability, strong robustness and real-time performance while achieving satisfactory control performance for the complex and nonlinear greenhouse climate control system, and it may provide a valuable reference to formulate environmental control strategies for actual application in greenhouse production. PMID:22778587

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

PubMed

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

2017-01-01

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

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

PubMed Central

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

2017-01-01

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

Design issues in a randomized controlled trial of a pre-emptive versus empiric antifungal strategy for invasive aspergillosis in patients with high-risk hematologic malignancies.

PubMed

Morrissey, C Orla; Chen, Sharon C-A; Sorrell, Tania C; Bradstock, Kenneth F; Szer, Jeffrey; Halliday, Catriona L; Gilroy, Nicole M; Schwarer, Anthony P; Slavin, Monica A

2011-02-01

Invasive aspergillosis (IA) is a major cause of mortality in patients with hematological malignancies, due largely to the inability of traditional culture and biopsy methods to make an early or accurate diagnosis. Diagnostic accuracy studies suggest that Aspergillus galactomannan (GM) enzyme immunoassay (ELISA) and Aspergillus PCR-based methods may overcome these limitations, but their impact on patient outcomes should be evaluated in a diagnostic randomized controlled trial (D-RCT). This article describes the methodology of a D-RCT which compares a new pre-emptive strategy (GM-ELISA- and Aspergillus PCR-driven antifungal therapy) with the standard fever-driven empiric antifungal treatment strategy. Issues including primary end-point and patient selection, duration of screening, choice of tests for the pre-emptive strategy, antifungal prophylaxis and bias control, which were considered in the design of the trial, are discussed. We suggest that the template presented herein is considered by researchers when evaluating the utility of new diagnostic tests (ClinicalTrials.gov number, NCT00163722).

MTPA control of mechanical sensorless IPMSM based on adaptive nonlinear control.

PubMed

Najjar-Khodabakhsh, Abbas; Soltani, Jafar

2016-03-01

In this paper, an adaptive nonlinear control scheme has been proposed for implementing maximum torque per ampere (MTPA) control strategy corresponding to interior permanent magnet synchronous motor (IPMSM) drive. This control scheme is developed in the rotor d-q axis reference frame using adaptive input-output state feedback linearization (AIOFL) method. The drive system control stability is supported by Lyapunov theory. The motor inductances are online estimated by an estimation law obtained by AIOFL. The estimation errors of these parameters are proved to be asymptotically converged to zero. Based on minimizing the motor current amplitude, the MTPA control strategy is performed by using the nonlinear optimization technique while considering the online reference torque. The motor reference torque is generated by a conventional rotor speed PI controller. By performing MTPA control strategy, the generated online motor d-q reference currents were used in AIOFL controller to obtain the SV-PWM reference voltages and the online estimation of the motor d-q inductances. In addition, the stator resistance is online estimated using a conventional PI controller. Moreover, the rotor position is detected using the online estimation of the stator flux and online estimation of the motor q-axis inductance. Simulation and experimental results obtained prove the effectiveness and the capability of the proposed control method. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Research on Precision Tracking on Fast Steering Mirror and Control Strategy

NASA Astrophysics Data System (ADS)

Di, Lin; Yi-ming, Wu; Fan, Zhu

2018-01-01

Fast steering mirror is a device used for controlling the beam direction precisely. Due to the short travel of the push-pull FSM, a compound fast steering mirror system driven by both limited-angle voice coil motor and push-pull FSM together is proposed. In the compound FSM system, limited-angle voice coil motor quickly swings at wide angle, while the push-pull FSM do high frequency movement in a small range, which provides the system with the high bandwidth and long travel. In the control strategy, the method of combining feed-forward control in Kalman filtering with auto-disturbance rejection control is used to improve trajectory tracking accuracy. The simulation result shows that tracking accuracy measured by the compound method can be improved by more than 5 times than that of the conventional PID.

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

PubMed Central

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

2017-01-01

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

Control strategy of grid-connected photovoltaic generation system based on GMPPT method

NASA Astrophysics Data System (ADS)

Wang, Zhongfeng; Zhang, Xuyang; Hu, Bo; Liu, Jun; Li, Ligang; Gu, Yongqiang; Zhou, Bowen

2018-02-01

There are multiple local maximum power points when photovoltaic (PV) array runs under partial shading condition (PSC).However, the traditional maximum power point tracking (MPPT) algorithm might be easily trapped in local maximum power points (MPPs) and cannot find the global maximum power point (GMPP). To solve such problem, a global maximum power point tracking method (GMPPT) is improved, combined with traditional MPPT method and particle swarm optimization (PSO) algorithm. Under different operating conditions of PV cells, different tracking algorithms are used. When the environment changes, the improved PSO algorithm is adopted to realize the global optimal search, and the variable step incremental conductance (INC) method is adopted to achieve MPPT in optimal local location. Based on the simulation model of the PV grid system built in Matlab/Simulink, comparative analysis of the tracking effect of MPPT by the proposed control algorithm and the traditional MPPT method under the uniform solar condition and PSC, validate the correctness, feasibility and effectiveness of the proposed control strategy.

Altered strategy in short-term memory for pictures in children with attention-deficit/hyperactivity disorder: a near-infrared spectroscopy study.

PubMed

Sanefuji, Masafumi; Yamashita, Hiroshi; Torisu, Hiroyuki; Takada, Yui; Imanaga, Hisako; Matsunaga, Mayumi; Ishizaki, Yoshito; Sakai, Yasunari; Yoshida, Keiko; Hara, Toshiro

2014-07-30

Strategy in short-term memory for serially presented pictures shifts gradually from a non-phonological to a phonological method as memory ability increases during typical childhood development. However, little is known about the development of this strategic change in children with attention-deficit/hyperactivity disorder (ADHD). To understand the neural basis of ADHD, we investigated short-term memory strategies using near-infrared spectroscopy. ADHD children aged from 6 to 12 years and age- and sex-matched control children were assessed in this study. Regional activity was monitored in the left ventrolateral prefrontal cortex to assess strategies used during short-term memory for visual or phonological objects. We examined the hypothesis that the strategic methods used would be correlated with memory ability. Higher memory ability and the phonological strategy were significantly correlated in the control group but not in the ADHD group. Intriguingly, ADHD children receiving methylphenidate treatment exhibited increased use of phonological strategy compared with those without. In conclusion, we found evidence of an altered strategy in short-term memory in ADHD children. The modulatory effect of methylphenidate indicates its therapeutic efficacy. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

New charging strategy for lithium-ion batteries based on the integration of Taguchi method and state of charge estimation

NASA Astrophysics Data System (ADS)

Vo, Thanh Tu; Chen, Xiaopeng; Shen, Weixiang; Kapoor, Ajay

2015-01-01

In this paper, a new charging strategy of lithium-polymer batteries (LiPBs) has been proposed based on the integration of Taguchi method (TM) and state of charge estimation. The TM is applied to search an optimal charging current pattern. An adaptive switching gain sliding mode observer (ASGSMO) is adopted to estimate the SOC which controls and terminates the charging process. The experimental results demonstrate that the proposed charging strategy can successfully charge the same types of LiPBs with different capacities and cycle life. The proposed charging strategy also provides much shorter charging time, narrower temperature variation and slightly higher energy efficiency than the equivalent constant current constant voltage charging method.

[Bibliometric analysis of literature regarding integrated schistosomiasis control strategy with emphasis on infectious source control].

PubMed

Qian, Yi-Li; Wang, Wei; Hong, Qing-Biao; Liang, You-Sheng

2014-12-01

To evaluate the outcomes of implementation of integrated schistosomiasis control strategy with emphasis on infectious source control using a bibliometric method. The literature pertaining to integrated schistosomiasis control strategy with emphasis on infectious source control was retrieved from CNKI, Wanfangdata, VIP, PubMed, Web of Science, BIOSIS and Google Scholar, and a bibliometric analysis of literature captured was performed. During the period from January 1, 2004 through September 30, 2014, a total of 94 publications regarding integrated schistosomiasis control strategy with emphasis on infectious source control were captured, including 78 Chinese articles (82.98%) and 16 English papers (17.02%). The Chinese literature was published in 21 national journals, and Chinese Journal of Schistosomiasis Control had the largest number of publications, consisting of 37.23% of total publications; 16 English papers were published in 12 international journals, and PLoS Neglected Tropical Diseases had the largest number of publications (3 publications). There were 37 affiliations publishing these 94 articles, and National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (16 publications), Anhui Institute of Schistosomiasis Control (12 publications) and Hunan Institute of Schistosomiasis Control (9 publications) ranked top three affiliations in number of publications. A total of 157 persons were co-authored in these 94 publications, and Wang, Zhou and Zhang ranked top 3 authors in number of publications. The integrated schistosomiasis control strategy with emphasis on infectious source control has been widely implemented in China, and the achievements obtained from the implementation of this strategy should be summarized and transmitted internationally.

Intelligent voltage control strategy for three-phase UPS inverters with output LC filter

NASA Astrophysics Data System (ADS)

Jung, J. W.; Leu, V. Q.; Dang, D. Q.; Do, T. D.; Mwasilu, F.; Choi, H. H.

2015-08-01

This paper presents a supervisory fuzzy neural network control (SFNNC) method for a three-phase inverter of uninterruptible power supplies (UPSs). The proposed voltage controller is comprised of a fuzzy neural network control (FNNC) term and a supervisory control term. The FNNC term is deliberately employed to estimate the uncertain terms, and the supervisory control term is designed based on the sliding mode technique to stabilise the system dynamic errors. To improve the learning capability, the FNNC term incorporates an online parameter training methodology, using the gradient descent method and Lyapunov stability theory. Besides, a linear load current observer that estimates the load currents is used to exclude the load current sensors. The proposed SFNN controller and the observer are robust to the filter inductance variations, and their stability analyses are described in detail. The experimental results obtained on a prototype UPS test bed with a TMS320F28335 DSP are presented to validate the feasibility of the proposed scheme. Verification results demonstrate that the proposed control strategy can achieve smaller steady-state error and lower total harmonic distortion when subjected to nonlinear or unbalanced loads compared to the conventional sliding mode control method.

Effectiveness and practicality of control strategies for African swine fever: what do we really know?

PubMed Central

Guinat, C.; Vergne, T.; Jurado-Diaz, C.; Sánchez-Vizcaíno, J. M.; Dixon, L.; Pfeiffer, D. U.

2017-01-01

African swine fever (ASF) is a major pig health problem, and the causative virus is moving closer to Western European regions where pig density is high. Stopping or slowing down the spread of ASF requires mitigation strategies that are both effective and practical. Based on the elicitation of ASF expert opinion, this study identified surveillance and intervention strategies for ASF that are perceived as the most effective by providing the best combination between effectiveness and practicality. Among the 20 surveillance strategies that were identified, passive surveillance of wild boar and syndromic surveillance of pig mortality were considered to be the most effective surveillance strategies for controlling ASF virus spread. Among the 22 intervention strategies that were identified, culling of all infected herds and movement bans for neighbouring herds were regarded as the most effective intervention strategies. Active surveillance and carcase removal in wild boar populations were rated as the most effective surveillance and intervention strategies, but were also considered to be the least practical, suggesting that more research is needed to develop more effective methods for controlling ASF in wild boar populations. PMID:27852963

A novel asynchronous access method with binary interfaces

PubMed Central

2008-01-01

Background Traditionally synchronous access strategies require users to comply with one or more time constraints in order to communicate intent with a binary human-machine interface (e.g., mechanical, gestural or neural switches). Asynchronous access methods are preferable, but have not been used with binary interfaces in the control of devices that require more than two commands to be successfully operated. Methods We present the mathematical development and evaluation of a novel asynchronous access method that may be used to translate sporadic activations of binary interfaces into distinct outcomes for the control of devices requiring an arbitrary number of commands to be controlled. With this method, users are required to activate their interfaces only when the device under control behaves erroneously. Then, a recursive algorithm, incorporating contextual assumptions relevant to all possible outcomes, is used to obtain an informed estimate of user intention. We evaluate this method by simulating a control task requiring a series of target commands to be tracked by a model user. Results When compared to a random selection, the proposed asynchronous access method offers a significant reduction in the number of interface activations required from the user. Conclusion This novel access method offers a variety of advantages over traditionally synchronous access strategies and may be adapted to a wide variety of contexts, with primary relevance to applications involving direct object manipulation. PMID:18959797

Optimal charge control strategies for stationary photovoltaic battery systems

NASA Astrophysics Data System (ADS)

Li, Jiahao; Danzer, Michael A.

2014-07-01

Battery systems coupled to photovoltaic (PV) modules for example fulfill one major function: they locally decouple PV generation and consumption of electrical power leading to two major effects. First, they reduce the grid load, especially at peak times and therewith reduce the necessity of a network expansion. And second, they increase the self-consumption in households and therewith help to reduce energy expenses. For the management of PV batteries charge control strategies need to be developed to reach the goals of both the distribution system operators and the local power producer. In this work optimal control strategies regarding various optimization goals are developed on the basis of the predicted household loads and PV generation profiles using the method of dynamic programming. The resulting charge curves are compared and essential differences discussed. Finally, a multi-objective optimization shows that charge control strategies can be derived that take all optimization goals into account.

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

PubMed

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

2017-01-01

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

Teacher Strategies and Interventions for Maltreated Children.

ERIC Educational Resources Information Center

Lowenthal, Barbara

2001-01-01

Suggests that teachers use classroom strategies (structure and routine, reasonable rules and limits, using appropriate methods of discipline, other positive behavior management techniques) and socio-emotional interventions (development of friendships, appropriate expressions of emotions, anger control, conflict management, and internal sense of…

A new compound control method for sine-on-random mixed vibration test

NASA Astrophysics Data System (ADS)

Zhang, Buyun; Wang, Ruochen; Zeng, Falin

2017-09-01

Vibration environmental test (VET) is one of the important and effective methods to provide supports for the strength design, reliability and durability test of mechanical products. A new separation control strategy was proposed to apply in multiple-input multiple-output (MIMO) sine on random (SOR) mixed mode vibration test, which is the advanced and intensive test type of VET. As the key problem of the strategy, correlation integral method was applied to separate the mixed signals which included random and sinusoidal components. The feedback control formula of MIMO linear random vibration system was systematically deduced in frequency domain, and Jacobi control algorithm was proposed in view of the elements, such as self-spectrum, coherence, and phase of power spectral density (PSD) matrix. Based on the excessive correction of excitation in sine vibration test, compression factor was introduced to reduce the excitation correction, avoiding the destruction to vibration table or other devices. The two methods were synthesized to be applied in MIMO SOR vibration test system. In the final, verification test system with the vibration of a cantilever beam as the control object was established to verify the reliability and effectiveness of the methods proposed in the paper. The test results show that the exceeding values can be controlled in the tolerance range of references accurately, and the method can supply theory and application supports for mechanical engineering.

Predictors of Nurses’ Intention and Behavior in Using Health Literacy Strategies in Patient Education Based on the Theory of Planned Behavior

PubMed Central

Sharifirad, Gholamreza; Mostafavi, Firoozeh; Reisi, Mahnouush; Mahaki, Behzad; Javadzade, Homamodin; Heydarabadi, Akbar Babaei; Esfahani, Mahmoud Nasr

2015-01-01

Background: Health literacy is one of the most important priorities for improving health care quality through enhancing patient-provider communication. Implementing health literacy strategies enable nurses to provide information and instructions for patients in a manner that is more commensurate and understandable. The purpose of this study was to investigate the factors affecting nurses’ intention to implement health literacy strategies in patient education based on theory of planned behavior. Methods: A cross-sectional study was done on 148 nurse practitioners of AL-Zahra educational hospital in Isfahan, Iran, using a descriptive-analytic method. Data collected via a standardized questionnaire based on theory of planned behavior constructed and analyzed by SPSS v.17 using ANOVA, Independent T-test, Pearson correlation and linear regression. Results: There was statistically significant correlation between using health literacy strategies and marriage status, attending in retraining courses, employment type, job history, and job status. Perceived behavioral control was the most powerful predictor of intention (β=0.417) and use health literacy strategies in patient education and behavior of nurses (β=0.33). Conclusion: According to the findings of this study, perceived behavioral control is a powerful determinant of nurses’ intention and behavior of using health literacy strategies in patient education. Hence we recommend nurse educators to pay special attention to the constructs of this theory mainly perceived behavioral control in retrain courses about patient education and health literacy strategies. PMID:25945078

The physicochemical process of bacterial attachment to abiotic surfaces: Challenges for mechanistic studies, predictability and the development of control strategies.

PubMed

Wang, Yi; Lee, Sui Mae; Dykes, Gary

2015-01-01

Bacterial attachment to abiotic surfaces can be explained as a physicochemical process. Mechanisms of the process have been widely studied but are not yet well understood due to their complexity. Physicochemical processes can be influenced by various interactions and factors in attachment systems, including, but not limited to, hydrophobic interactions, electrostatic interactions and substratum surface roughness. Mechanistic models and control strategies for bacterial attachment to abiotic surfaces have been established based on the current understanding of the attachment process and the interactions involved. Due to a lack of process control and standardization in the methodologies used to study the mechanisms of bacterial attachment, however, various challenges are apparent in the development of models and control strategies. In this review, the physicochemical mechanisms, interactions and factors affecting the process of bacterial attachment to abiotic surfaces are described. Mechanistic models established based on these parameters are discussed in terms of their limitations. Currently employed methods to study these parameters and bacterial attachment are critically compared. The roles of these parameters in the development of control strategies for bacterial attachment are reviewed, and the challenges that arise in developing mechanistic models and control strategies are assessed.

A Comparative Study of Thought Fusion Beliefs and Thought Control Strategies in Patient With Obsessive-Compulsive Disorder, Major Depressive Disorder and Normal People

PubMed Central

Amiri Pichakolaei, Ahmad; Fahimi, Samad; Bakhshipour Roudsari, Abbas; Fakhari, Ali; Akbari, Ebrahim; Rahimkhanli, Masoumeh

2014-01-01

Objective: The present study aimed to investigate the metacognitive model of obsessive-compulsive disorder (OCD), through a comparative study of thought fusion beliefs and thought control strategies between patients with OCD, depression, and normal people. Methods: This is a causal-comparative study. About 20 patients were selected with OCD, and 20 patients with major depression disorder (MDD), and 20 normal individuals. Participants completed a thought fusion instrument and thought control questionnaire. Data were analyzed using multivariate analysis of variance. Results: Results indicated that patients with OCD obtained higher scores than two other groups. Also, there was a statistical significant difference between the three groups in thought control strategies and punishment, worry, and distraction subscales. Conclusion: Therefore, the results of the present study supported the metacognitive model of obsessive and showed thought fusion beliefs and thought control strategies can be effective in onset and continuity of OCD. PMID:25780373

The study on the control strategy of micro grid considering the economy of energy storage operation

NASA Astrophysics Data System (ADS)

Ma, Zhiwei; Liu, Yiqun; Wang, Xin; Li, Bei; Zeng, Ming

2017-08-01

To optimize the running of micro grid to guarantee the supply and demand balance of electricity, and to promote the utilization of renewable energy. The control strategy of micro grid energy storage system is studied. Firstly, the mixed integer linear programming model is established based on the receding horizon control. Secondly, the modified cuckoo search algorithm is proposed to calculate the model. Finally, a case study is carried out to study the signal characteristic of micro grid and batteries under the optimal control strategy, and the convergence of the modified cuckoo search algorithm is compared with others to verify the validity of the proposed model and method. The results show that, different micro grid running targets can affect the control strategy of energy storage system, which further affect the signal characteristics of the micro grid. Meanwhile, the convergent speed, computing time and the economy of the modified cuckoo search algorithm are improved compared with the traditional cuckoo search algorithm and differential evolution algorithm.

[Feedforward control strategy and its application in quality improvement of ethanol precipitation process of danhong injection].

PubMed

Yan, Bin-Jun; Guo, Zheng-Tai; Qu, Hai-Bin; Zhao, Bu-Chang; Zhao, Tao

2013-06-01

In this work, a feedforward control strategy basing on the concept of quality by design was established for the manufacturing process of traditional Chinese medicine to reduce the impact of the quality variation of raw materials on drug. In the research, the ethanol precipitation process of Danhong injection was taken as an application case of the method established. Box-Behnken design of experiments was conducted. Mathematical models relating the attributes of the concentrate, the process parameters and the quality of the supernatants produced were established. Then an optimization model for calculating the best process parameters basing on the attributes of the concentrate was built. The quality of the supernatants produced by ethanol precipitation with optimized and non-optimized process parameters were compared. The results showed that using the feedforward control strategy for process parameters optimization can control the quality of the supernatants effectively. The feedforward control strategy proposed can enhance the batch-to-batch consistency of the supernatants produced by ethanol precipitation.

Medication management strategies used by older adults with heart failure: A systems-based analysis.

PubMed

Mickelson, Robin S; Holden, Richard J

2017-09-01

Older adults with heart failure use strategies to cope with the constraining barriers impeding medication management. Strategies are behavioral adaptations that allow goal achievement despite these constraining conditions. When strategies do not exist, are ineffective or maladaptive, medication performance and health outcomes are at risk. While constraints to medication adherence are described in literature, strategies used by patients to manage medications are less well-described or understood. Guided by cognitive engineering concepts, the aim of this study was to describe and analyze the strategies used by older adults with heart failure to achieve their medication management goals. This mixed methods study employed an empirical strategies analysis method to elicit medication management strategies used by older adults with heart failure. Observation and interview data collected from 61 older adults with heart failure and 31 caregivers were analyzed using qualitative content analysis to derive categories, patterns and themes within and across cases. Data derived thematic sub-categories described planned and ad hoc methods of strategic adaptations. Stable strategies proactively adjusted the medication management process, environment, or the patients themselves. Patients applied situational strategies (planned or ad hoc) to irregular or unexpected situations. Medication non-adherence was a strategy employed when life goals conflicted with medication adherence. The health system was a source of constraints without providing commensurate strategies. Patients strived to control their medication system and achieve goals using adaptive strategies. Future patient self-mangement research can benefit from methods and theories used to study professional work, such as strategies analysis.

Multi-criteria decision making approaches for quality control of genome-wide association studies.

PubMed

Malovini, Alberto; Rognoni, Carla; Puca, Annibale; Bellazzi, Riccardo

2009-03-01

Experimental errors in the genotyping phases of a Genome-Wide Association Study (GWAS) can lead to false positive findings and to spurious associations. An appropriate quality control phase could minimize the effects of this kind of errors. Several filtering criteria can be used to perform quality control. Currently, no formal methods have been proposed for taking into account at the same time these criteria and the experimenter's preferences. In this paper we propose two strategies for setting appropriate genotyping rate thresholds for GWAS quality control. These two approaches are based on the Multi-Criteria Decision Making theory. We have applied our method on a real dataset composed by 734 individuals affected by Arterial Hypertension (AH) and 486 nonagenarians without history of AH. The proposed strategies appear to deal with GWAS quality control in a sound way, as they lead to rationalize and make explicit the experimenter's choices thus providing more reproducible results.

A decision tree-based on-line preventive control strategy for power system transient instability prevention

NASA Astrophysics Data System (ADS)

Xu, Yan; Dong, Zhao Yang; Zhang, Rui; Wong, Kit Po

2014-02-01

Maintaining transient stability is a basic requirement for secure power system operations. Preventive control deals with modifying the system operating point to withstand probable contingencies. In this article, a decision tree (DT)-based on-line preventive control strategy is proposed for transient instability prevention of power systems. Given a stability database, a distance-based feature estimation algorithm is first applied to identify the critical generators, which are then used as features to develop a DT. By interpreting the splitting rules of DT, preventive control is realised by formulating the rules in a standard optimal power flow model and solving it. The proposed method is transparent in control mechanism, on-line computation compatible and convenient to deal with multi-contingency. The effectiveness and efficiency of the method has been verified on New England 10-machine 39-bus test system.

Trainer Interventions as Instructional Strategies in Air Traffic Control Training

ERIC Educational Resources Information Center

Koskela, Inka; Palukka, Hannele

2011-01-01

Purpose: This paper aims to identify methods of guidance and supervision used in air traffic control training. It also aims to show how these methods facilitate trainee participation in core work activities. Design/methodology/approach: The paper applies the tools of conversation analysis and ethnomethodology to explore the ways in which trainers…

Biological Control of Mosquito Vectors: Past, Present, and Future.

PubMed

Benelli, Giovanni; Jeffries, Claire L; Walker, Thomas

2016-10-03

Mosquitoes represent the major arthropod vectors of human disease worldwide transmitting malaria, lymphatic filariasis, and arboviruses such as dengue virus and Zika virus. Unfortunately, no treatment (in the form of vaccines or drugs) is available for most of these diseases andvectorcontrolisstillthemainformofprevention. Thelimitationsoftraditionalinsecticide-based strategies, particularly the development of insecticide resistance, have resulted in significant efforts to develop alternative eco-friendly methods. Biocontrol strategies aim to be sustainable and target a range of different mosquito species to reduce the current reliance on insecticide-based mosquito control. In thisreview, weoutline non-insecticide basedstrategiesthat havebeenimplemented orare currently being tested. We also highlight the use of mosquito behavioural knowledge that can be exploited for control strategies.

Neural network-based sliding mode control for atmospheric-actuated spacecraft formation using switching strategy

NASA Astrophysics Data System (ADS)

Sun, Ran; Wang, Jihe; Zhang, Dexin; Shao, Xiaowei

2018-02-01

This paper presents an adaptive neural networks-based control method for spacecraft formation with coupled translational and rotational dynamics using only aerodynamic forces. It is assumed that each spacecraft is equipped with several large flat plates. A coupled orbit-attitude dynamic model is considered based on the specific configuration of atmospheric-based actuators. For this model, a neural network-based adaptive sliding mode controller is implemented, accounting for system uncertainties and external perturbations. To avoid invalidation of the neural networks destroying stability of the system, a switching control strategy is proposed which combines an adaptive neural networks controller dominating in its active region and an adaptive sliding mode controller outside the neural active region. An optimal process is developed to determine the control commands for the plates system. The stability of the closed-loop system is proved by a Lyapunov-based method. Comparative results through numerical simulations illustrate the effectiveness of executing attitude control while maintaining the relative motion, and higher control accuracy can be achieved by using the proposed neural-based switching control scheme than using only adaptive sliding mode controller.

On The Behavior of Subgradient Projections Methods for Convex Feasibility Problems in Euclidean Spaces

PubMed Central

Butnariu, Dan; Censor, Yair; Gurfil, Pini; Hadar, Ethan

2010-01-01

We study some methods of subgradient projections for solving a convex feasibility problem with general (not necessarily hyperplanes or half-spaces) convex sets in the inconsistent case and propose a strategy that controls the relaxation parameters in a specific self-adapting manner. This strategy leaves enough user-flexibility but gives a mathematical guarantee for the algorithm’s behavior in the inconsistent case. We present numerical results of computational experiments that illustrate the computational advantage of the new method. PMID:20182556

On The Behavior of Subgradient Projections Methods for Convex Feasibility Problems in Euclidean Spaces.

PubMed

Butnariu, Dan; Censor, Yair; Gurfil, Pini; Hadar, Ethan

2008-07-03

We study some methods of subgradient projections for solving a convex feasibility problem with general (not necessarily hyperplanes or half-spaces) convex sets in the inconsistent case and propose a strategy that controls the relaxation parameters in a specific self-adapting manner. This strategy leaves enough user-flexibility but gives a mathematical guarantee for the algorithm's behavior in the inconsistent case. We present numerical results of computational experiments that illustrate the computational advantage of the new method.

Real-time discrete suboptimal control for systems with input and state delays: Experimental tests on a dehydration process.

PubMed

Rodríguez-Guerrero, Liliam; Santos-Sánchez, Omar-Jacobo; Cervantes-Escorcia, Nicolás; Romero, Hugo

2017-11-01

This article presents a suboptimal control strategy with finite horizon for affine nonlinear discrete systems with both state and input delays. The Dynamic Programming Approach is used to obtain the suboptimal control sequence, but in order to avoid the computation of the Bellman functional, a numerical approximation of this function is proposed in every step. The feasibility of our proposal is demonstrated via an experimental test on a dehydration process and the obtained results show a good performance and behavior of this process. Then in order to demonstrate the benefits of using this kind of control strategy, the results are compared with a non optimal control strategy, particularly with respect to results produced by an industrial Proportional Integral Derivative (PID) Honeywell controller, which is tuned using the Ziegler-Nichols method. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Wolbachia: A biological control strategy against arboviral diseases.

PubMed

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

2016-01-01

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

Variable speed limit strategies analysis with link transmission model on urban expressway

NASA Astrophysics Data System (ADS)

Li, Shubin; Cao, Danni

2018-02-01

The variable speed limit (VSL) is a kind of active traffic management method. Most of the strategies are used in the expressway traffic flow control in order to ensure traffic safety. However, the urban expressway system is the main artery, carrying most traffic pressure. It has similar traffic characteristics with the expressways between cities. In this paper, the improved link transmission model (LTM) combined with VSL strategies is proposed, based on the urban expressway network. The model can simulate the movement of the vehicles and the shock wave, and well balance the relationship between the amount of calculation and accuracy. Furthermore, the optimal VSL strategy can be proposed based on the simulation method. It can provide management strategies for managers. Finally, a simple example is given to illustrate the model and method. The selected indexes are the average density, the average speed and the average flow on the traffic network in the simulation. The simulation results show that the proposed model and method are feasible. The VSL strategy can effectively alleviate traffic congestion in some cases, and greatly promote the efficiency of the transportation system.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dragicevic, Tomislav; Lu, Xiaonan; Vasquez, Juan

2015-01-01

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

Accuracy Improvement of Multi-Axis Systems Based on Laser Correction of Volumetric Geometric Errors

NASA Astrophysics Data System (ADS)

Teleshevsky, V. I.; Sokolov, V. A.; Pimushkin, Ya I.

2018-04-01

The article describes a volumetric geometric errors correction method for CNC- controlled multi-axis systems (machine-tools, CMMs etc.). The Kalman’s concept of “Control and Observation” is used. A versatile multi-function laser interferometer is used as Observer in order to measure machine’s error functions. A systematic error map of machine’s workspace is produced based on error functions measurements. The error map results into error correction strategy. The article proposes a new method of error correction strategy forming. The method is based on error distribution within machine’s workspace and a CNC-program postprocessor. The postprocessor provides minimal error values within maximal workspace zone. The results are confirmed by error correction of precision CNC machine-tools.

A satellite digital controller or 'play that PID tune again, Sam'. [Position, Integral, Derivative feedback control algorithm for design strategy

NASA Technical Reports Server (NTRS)

Seltzer, S. M.

1976-01-01

The problem discussed is to design a digital controller for a typical satellite. The controlled plant is considered to be a rigid body acting in a plane. The controller is assumed to be a digital computer which, when combined with the proposed control algorithm, can be represented as a sampled-data system. The objective is to present a design strategy and technique for selecting numerical values for the control gains (assuming position, integral, and derivative feedback) and the sample rate. The technique is based on the parameter plane method and requires that the system be amenable to z-transform analysis.

A study of the impact of collaborative learning on student learning of major concepts in a microbiology laboratory exercise

NASA Astrophysics Data System (ADS)

Baumgarten, Kristyne A.

This study investigated the possible relationship between collaborative learning strategies and the learning of core concepts. This study examined the differences between two groups of nursing students enrolled in an introductory microbiology laboratory course. The control group consisted of students enrolled in sections taught in the traditional method. The experimental group consisted of those students enrolled in the sections using collaborative learning strategies. The groups were assessed on their degrees of learning core concepts using a pre-test/post-test method. Scores from the groups' laboratory reports were also analyzed. There was no difference in the two group's pre-test scores. The post-test scores of the experimental group averaged 11 points higher than the scores of the control group. The lab report scores of the experimental group averaged 15 points higher than those scores of the control group. The data generated from this study demonstrated that collaborative learning strategies can be used to increase students learning of core concepts in microbiology labs.

Cost-Effectiveness of Chagas Disease Vector Control Strategies in Northwestern Argentina

PubMed Central

Vazquez-Prokopec, Gonzalo M.; Spillmann, Cynthia; Zaidenberg, Mario; Kitron, Uriel; Gürtler, Ricardo E.

2009-01-01

Background Control and prevention of Chagas disease rely mostly on residual spraying of insecticides. In Argentina, vector control shifted from a vertical to a fully horizontal strategy based on community participation between 1992 and 2004. The effects of such strategy on Triatoma infestans, the main domestic vector, and on disease transmission have not been assessed. Methods and Findings Based on retrospective (1993–2004) records from the Argentinean Ministry of Health for the Moreno Department, Northwestern Argentina, we performed a cost-effectiveness (CE) analysis and compared the observed CE of the fully horizontal vector control strategy with the expected CE for a vertical or a mixed (i.e., vertical attack phase followed by horizontal surveillance) strategy. Total direct costs (in 2004 US$) of the horizontal and mixed strategies were, respectively, 3.3 and 1.7 times lower than the costs of the vertical strategy, due to reductions in personnel costs. The estimated CE ratios for the vertical, mixed and horizontal strategies were US$132, US$82 and US$45 per averted human case, respectively. When per diems were excluded from the costs (i.e., simulating the decentralization of control activities), the CE of vertical, mixed and horizontal strategies was reduced to US$60, US$42 and US$32 per averted case, respectively. Conclusions and Significance The mixed strategy would have averted between 1.6 and 4.0 times more human cases than the fully horizontal strategy, and would have been the most cost-effective option to interrupt parasite transmission in the Department. In rural and dispersed areas where waning vertical vector programs cannot accomplish full insecticide coverage, alternative strategies need to be developed. If properly implemented, community participation represents not only the most appealing but also the most cost-effective alternative to accomplish such objectives. PMID:19156190

Epidemiology and control of east coast fever in Zambia. A field trial with traditionally managed Sanga cattle.

PubMed

Minjauw, B; Otte, M J; James, A D

1998-06-29

The main objective of the reported field trial was to compare different East Coast Fever (ECF) control strategies for their efficacy, effect on cattle productivity and cost-effectiveness. Five strategies were tested in groups of traditionally managed Sanga cattle over a period of 2.5 years. Two groups were under intensive tick control, one group immunized by the infection and treatment method and the other non-immunized. Two groups were under no tick control, one group immunized and the other non-immunized (the control group). The fifth group was under strategic tick control and was immunized against ECF. All ECF control methods tested significantly reduced mortality, but no marked differences to the control group were seen in other production parameters. No difference in mortality was observed between animals protected from ECF by immunization or by tick control. The most cost-effective method of controlling the disease was by immunization. A financial analysis showed that under the prevailing conditions the break-even price for immunization ranged from US$21.5 to US$25.7 depending of the proportion of reactors. The carrier state induced by immunization did not lead to a persistent high incidence of ECF in non-immunized animals using the same grazing area.

Malaria vector control: from past to future.

PubMed

Raghavendra, Kamaraju; Barik, Tapan K; Reddy, B P Niranjan; Sharma, Poonam; Dash, Aditya P

2011-04-01

Malaria is one of the most common vector-borne diseases widespread in the tropical and subtropical regions. Despite considerable success of malaria control programs in the past, malaria still continues as a major public health problem in several countries. Vector control is an essential part for reducing malaria transmission and became less effective in recent years, due to many technical and administrative reasons, including poor or no adoption of alternative tools. Of the different strategies available for vector control, the most successful are indoor residual spraying and insecticide-treated nets (ITNs), including long-lasting ITNs and materials. Earlier DDT spray has shown spectacular success in decimating disease vectors but resulted in development of insecticide resistance, and to control the resistant mosquitoes, organophosphates, carbamates, and synthetic pyrethroids were introduced in indoor residual spraying with needed success but subsequently resulted in the development of widespread multiple insecticide resistance in vectors. Vector control in many countries still use insecticides in the absence of viable alternatives. Few developments for vector control, using ovitraps, space spray, biological control agents, etc., were encouraging when used in limited scale. Likewise, recent introduction of safer vector control agents, such as insect growth regulators, biocontrol agents, and natural plant products have yet to gain the needed scale of utility for vector control. Bacterial pesticides are promising and are effective in many countries. Environmental management has shown sufficient promise for vector control and disease management but still needs advocacy for inter-sectoral coordination and sometimes are very work-intensive. The more recent genetic manipulation and sterile insect techniques are under development and consideration for use in routine vector control and for these, standardized procedures and methods are available but need thorough understanding of biology, ethical considerations, and sufficiently trained manpower for implementation being technically intensive methods. All the methods mentioned in the review that are being implemented or proposed for implementation needs effective inter-sectoral coordination and community participation. The latest strategy is evolution-proof insecticides that include fungal biopesticides, Wolbachia, and Denso virus that essentially manipulate the life cycle of the mosquitoes were found effective but needs more research. However, for effective vector control, integrated vector management methods, involving use of combination of effective tools, is needed and is also suggested by Global Malaria Control Strategy. This review article raises issues associated with the present-day vector control strategies and state opportunities with a focus on ongoing research and recent advances to enable to sustain the gains achieved so far.

Model-based rational feedback controller design for closed-loop deep brain stimulation of Parkinson's disease

NASA Astrophysics Data System (ADS)

Gorzelic, P.; Schiff, S. J.; Sinha, A.

2013-04-01

Objective. To explore the use of classical feedback control methods to achieve an improved deep brain stimulation (DBS) algorithm for application to Parkinson's disease (PD). Approach. A computational model of PD dynamics was employed to develop model-based rational feedback controller design. The restoration of thalamocortical relay capabilities to patients suffering from PD is formulated as a feedback control problem with the DBS waveform serving as the control input. Two high-level control strategies are tested: one that is driven by an online estimate of thalamic reliability, and another that acts to eliminate substantial decreases in the inhibition from the globus pallidus interna (GPi) to the thalamus. Control laws inspired by traditional proportional-integral-derivative (PID) methodology are prescribed for each strategy and simulated on this computational model of the basal ganglia network. Main Results. For control based upon thalamic reliability, a strategy of frequency proportional control with proportional bias delivered the optimal control achieved for a given energy expenditure. In comparison, control based upon synaptic inhibitory output from the GPi performed very well in comparison with those of reliability-based control, with considerable further reduction in energy expenditure relative to that of open-loop DBS. The best controller performance was amplitude proportional with derivative control and integral bias, which is full PID control. We demonstrated how optimizing the three components of PID control is feasible in this setting, although the complexity of these optimization functions argues for adaptive methods in implementation. Significance. Our findings point to the potential value of model-based rational design of feedback controllers for Parkinson's disease.

Model-based rational feedback controller design for closed-loop deep brain stimulation of Parkinson's disease.

PubMed

Gorzelic, P; Schiff, S J; Sinha, A

2013-04-01

To explore the use of classical feedback control methods to achieve an improved deep brain stimulation (DBS) algorithm for application to Parkinson's disease (PD). A computational model of PD dynamics was employed to develop model-based rational feedback controller design. The restoration of thalamocortical relay capabilities to patients suffering from PD is formulated as a feedback control problem with the DBS waveform serving as the control input. Two high-level control strategies are tested: one that is driven by an online estimate of thalamic reliability, and another that acts to eliminate substantial decreases in the inhibition from the globus pallidus interna (GPi) to the thalamus. Control laws inspired by traditional proportional-integral-derivative (PID) methodology are prescribed for each strategy and simulated on this computational model of the basal ganglia network. For control based upon thalamic reliability, a strategy of frequency proportional control with proportional bias delivered the optimal control achieved for a given energy expenditure. In comparison, control based upon synaptic inhibitory output from the GPi performed very well in comparison with those of reliability-based control, with considerable further reduction in energy expenditure relative to that of open-loop DBS. The best controller performance was amplitude proportional with derivative control and integral bias, which is full PID control. We demonstrated how optimizing the three components of PID control is feasible in this setting, although the complexity of these optimization functions argues for adaptive methods in implementation. Our findings point to the potential value of model-based rational design of feedback controllers for Parkinson's disease.

A simple approach to optimal control of invasive species.

PubMed

Hastings, Alan; Hall, Richard J; Taylor, Caz M

2006-12-01

The problem of invasive species and their control is one of the most pressing applied issues in ecology today. We developed simple approaches based on linear programming for determining the optimal removal strategies of different stage or age classes for control of invasive species that are still in a density-independent phase of growth. We illustrate the application of this method to the specific example of invasive Spartina alterniflora in Willapa Bay, WA. For all such systems, linear programming shows in general that the optimal strategy in any time step is to prioritize removal of a single age or stage class. The optimal strategy adjusts which class is the focus of control through time and can be much more cost effective than prioritizing removal of the same stage class each year.

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

PubMed Central

Box, Simon

2014-01-01

Optimal switching of traffic lights on a network of junctions is a computationally intractable problem. In this research, road traffic networks containing signallized junctions are simulated. A computer game interface is used to enable a human ‘player’ to control the traffic light settings on the junctions within the simulation. A supervised learning approach, based on simple neural network classifiers can be used to capture human player's strategies in the game and thus develop a human-trained machine control (HuTMaC) system that approaches human levels of performance. Experiments conducted within the simulation compare the performance of HuTMaC to two well-established traffic-responsive control systems that are widely deployed in the developed world and also to a temporal difference learning-based control method. In all experiments, HuTMaC outperforms the other control methods in terms of average delay and variance over delay. The conclusion is that these results add weight to the suggestion that HuTMaC may be a viable alternative, or supplemental method, to approximate optimization for some practical engineering control problems where the optimal strategy is computationally intractable. PMID:26064570

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

PubMed

Box, Simon

2014-12-01

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

A flight-phase terrain following control strategy for stable and robust hopping of a one-legged robot under large terrain variations.

PubMed

Shemer, Natan; Degani, Amir

2017-08-04

This work demonstrates a simple, once per step, flight-control method for robots running on a planar unknown rough-terrain environment. The robot used to exemplify these control strategies is the ParkourBot, a spring loaded inverted pendulum (SLIP)-based robot. The SLIP model is widely used for the description of humans and animals running motion and has been the basis for many robots. A known control scheme for increasing robustness of the conservative, SLIP model is the swing leg retraction (SLR) method. Despite of the SLR's popularity, it is not intended to be used on the more realistic, non-conservative damped SLIP model. On the damped SLIP model, the SLR controller failed to provide adequate results, therefore, we have derived a new simple, flight-phase control method called polynomial energy insertion (PEI). The new PEI method is based on the dead-beat solution of the damped simplified instantaneous SLIP (iSLIP) model, which assumes an infinitely stiff spring. Unlike the SLR which, starting from apex, changes the leg angle monotonically during flight, the PEI requires the leg length (hence, energy insertion) to change monotonically throughout the flight phase. Interestingly, the leg angle remains nearly constant. In simulations and experiments, we have compared the newly developed PEI to the previous SLR method. We have found that since the SLR does not control the horizontal velocity, it looses its stability under rough terrain. The PEI method was able to control the horizontal velocity and height from ground and hence showed great improvement in robustness to rough terrain. Moreover, in both simulations and experiments the PEI methods showed an increase in the mean jumps to failure of more than 30% compared to SLR-based controllers.

METHODS FOR OPTIMIZING URBAN WET-WEATHER CONTROL SYSTEM

EPA Science Inventory

To minimize impacts of urban nonpoint source pollution and associated costs of control (storage and treatment) associated with wet-weather flows (WWFs), stormwater runoff volumes and pollutant loads must be reduced. A number of control strategies, so-called “best management pract...

Possible application of a nematophagous fungus as a biological control agent of parasitic nematodes on commercial sheep farms in South Africa.

PubMed

Faedo, M; Krecek, R C

2002-03-01

Biological control of parasitic nematodes of livestock is currently under development and represents another tool that may be integrated into helminth parasite control strategies. This paper presents a brief introduction to commercial sheep farming in South Africa and currently available nematode parasite control methods. These include the FAMACHA clinical assay, strategies of pasture management, dilution of resistant worm species by introduction of susceptible worms, breed resistant sheep and nutritional supplementation. The purpose of this paper is to outline the principles of biological control using nematophagous fungi and how it may be applied on sheep farms in South Africa.

Family Food Providers’ Perceptions of the Causes of Obesity and Effectiveness of Weight Control Strategies in Five Countries in the Asia Pacific Region: A Cross-Sectional Survey

PubMed Central

Worsley, Anthony; Wang, Wei; Sarmugam, Rani; Pham, Quynh; Februhartanty, Judhiastuty; Ridley, Stacey

2017-01-01

The rise of the middle classes in developing countries and the associated epidemiological transition raises the importance of assessing this population group’s awareness of the causes of obesity and effective weight control strategies in order to develop effective health promotion strategies. The study aimed to examine the perceptions of the causes of obesity and weight control strategies held by middle class household food providers in Melbourne, Singapore, Shanghai, Indonesia and Vietnam. An online survey was conducted in late 2013, early 2014 among 3945 respondents. Information about body weight concerns, perceived causes of obesity, effectiveness of weight control methods, demographics, self-reported height and weight, and personal values was elicited. Confirmatory factor analyses (CFA) derived nine reliable factors which were used in structural equation modelling (SEM). Two thirds of respondents were trying to change their body weight, of them, 71% were trying to lose weight. The CFA and SEM showed that demographics, region of residence, personal values and perceptions of the causes of obesity (Unhealthy food behaviours, influences Beyond personal control and Environmental influences) had direct and indirect associations with three weight control methods factors, named: Healthy habits, Eat less, sit less, and Dieting. Middle class food providers in the study regions share public health views of obesity causation and personal weight control. These findings could inform public health and food policies, and the design of public health interventions and communications. Further research is required among lower socio economic status (SES) populations. PMID:28106781

Energy saving control strategies for Haliscomenobacter hydrossis filamentous sludge bulking in the A/O process treating real low carbon/nitrogen domestic wastewater.

PubMed

Jiao, Erlong; Gao, Chundi; Li, Renfei; Tian, Ye; Peng, Yongzhen

2017-07-16

The control strategies of energy saving for filamentous sludge bulking were investigated in the A/O process under low dissolved oxygen (DO) with low carbon/nitrogen (C/N) ratio, and the dominant filamentous bacteria were identified by using fluorescent in situ hybridization. Initially, the sludge volume index reached nearly 500 mL/g and serious bulking occurred when the DO value was 0.5 mg/L, with Haliscomenobacter hydrossis as the major filamentous bacteria in the bulking sludge. Later on, the compartment number increased in the aerobic zone, increasing by this way DO, to control serious bulking. Increasing DO to 1 mg/L based on the increase of compartment number in the aerobic zone was the favorable controlling method, which solved the sludge loss, improved the effluent quality to the national discharge standard and allowed for energy costs saving. As a result, the effective control method for H. hydrossis filamentous sludge bulking provided the economical, convenient and longstanding method for most municipal wastewater treatment plants treating real low C/N domestic wastewater.

Improved direct torque control of an induction generator used in a wind conversion system connected to the grid.

PubMed

Abdelli, Radia; Rekioua, Djamila; Rekioua, Toufik; Tounzi, Abdelmounaïm

2013-07-01

This paper presents a modulated hysteresis direct torque control (MHDTC) applied to an induction generator (IG) used in wind energy conversion systems (WECs) connected to the electrical grid through a back-to-back converter. The principle of this strategy consists in superposing to the torque reference a triangular signal, as in the PWM strategy, with the desired switching frequency. This new modulated reference is compared to the estimated torque by using a hysteresis controller as in the classical direct torque control (DTC). The aim of this new approach is to lead to a constant frequency and low THD in grid current with a unit power factor and a minimum voltage variation despite the wind variation. To highlight the effectiveness of the proposed method, a comparison was made with classical DTC and field oriented control method (FOC). The obtained simulation results, with a variable wind profile, show an adequate dynamic of the conversion system using the proposed method compared to the classical approaches. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

Eliminating Plasmodium falciparum in Hainan, China: a study on the use of behavioural change communication intervention to promote malaria prevention in mountain worker populations.

PubMed

He, Chang-hua; Hu, Xi-min; Wang, Guang-ze; Zhao, Wei; Sun, Ding-wei; Li, Yu-chun; Chen, Chun-xiang; Du, Jian-wei; Wang, Shan-qing

2014-07-13

In the island of Hainan, the great majority of malaria cases occur in mountain worker populations. Using the behavioral change communication (BCC) strategy, an interventional study was conducted to promote mountain worker malaria prevention at a test site. This study found the methods and measures that are suitable for malaria prevention among mountain worker populations. During the Plasmodium falciparum elimination stage in Hainan, a representative sampling method was used to establish testing and control sites in areas of Hainan that were both affected by malaria and had a relatively high density of mountain workers. Two different methods were used: a BCC strategy and a conventional strategy as a control. Before and after the intervention, house visits, core group discussions, and structural surveys were utilized to collect qualitative and quantitative data regarding mountain worker populations (including knowledge, attitudes, and practices [KAPs]; infection status; and serological data), and these data from the testing and control areas were compared to evaluate the effectiveness of BCC strategies in the prevention of malaria. In the BCC malaria prevention strategy testing areas, the accuracy rates of malaria-related KAP were significantly improved among mountain worker populations. The accuracy rates in the 3 aspects of malaria-related KAP increased from 37.73%, 37.00%, and 43.04% to 89.01%, 91.53%, and 92.25%, respectively. The changes in all 3 aspects of KAP were statistically significant (p < 0.01). In the control sites, the changes in the indices were not as marked as in the testing areas, and the change was not statistically significant (p > 0.05). Furthermore, in the testing areas, both the percentage testing positive in the serum malaria indirect fluorescent antibody test (IFAT) and the number of people inflicted decreased more significantly than in the control sites (p < 0.01). The use of the BCC strategy significantly improved the ability of mountain workers in Hainan to avoid malarial infection. Educational and promotional materials and measures were developed and selected in the process, and hands-on experience was gained that will help achieve the goal of total malaria elimination in Hainan.

Fault-tolerant nonlinear adaptive flight control using sliding mode online learning.

PubMed

Krüger, Thomas; Schnetter, Philipp; Placzek, Robin; Vörsmann, Peter

2012-08-01

An expanded nonlinear model inversion flight control strategy using sliding mode online learning for neural networks is presented. The proposed control strategy is implemented for a small unmanned aircraft system (UAS). This class of aircraft is very susceptible towards nonlinearities like atmospheric turbulence, model uncertainties and of course system failures. Therefore, these systems mark a sensible testbed to evaluate fault-tolerant, adaptive flight control strategies. Within this work the concept of feedback linearization is combined with feed forward neural networks to compensate for inversion errors and other nonlinear effects. Backpropagation-based adaption laws of the network weights are used for online training. Within these adaption laws the standard gradient descent backpropagation algorithm is augmented with the concept of sliding mode control (SMC). Implemented as a learning algorithm, this nonlinear control strategy treats the neural network as a controlled system and allows a stable, dynamic calculation of the learning rates. While considering the system's stability, this robust online learning method therefore offers a higher speed of convergence, especially in the presence of external disturbances. The SMC-based flight controller is tested and compared with the standard gradient descent backpropagation algorithm in the presence of system failures. Copyright © 2012 Elsevier Ltd. All rights reserved.

Closed-Loop Control of Chemical Injection Rate for a Direct Nozzle Injection System.

PubMed

Cai, Xiang; Walgenbach, Martin; Doerpmond, Malte; Schulze Lammers, Peter; Sun, Yurui

2016-01-20

To realize site-specific and variable-rate application of agricultural pesticides, accurately metering and controlling the chemical injection rate is necessary. This study presents a prototype of a direct nozzle injection system (DNIS) by which chemical concentration transport lag was greatly reduced. In this system, a rapid-reacting solenoid valve (RRV) was utilized for injecting chemicals, driven by a pulse-width modulation (PWM) signal at 100 Hz, so with varying pulse width the chemical injection rate could be adjusted. Meanwhile, a closed-loop control strategy, proportional-integral-derivative (PID) method, was applied for metering and stabilizing the chemical injection rate. In order to measure chemical flow rates and input them into the controller as a feedback in real-time, a thermodynamic flowmeter that was independent of chemical viscosity was used. Laboratory tests were conducted to assess the performance of DNIS and PID control strategy. Due to the nonlinear input-output characteristics of the RRV, a two-phase PID control process obtained better effects as compared with single PID control strategy. Test results also indicated that the set-point chemical flow rate could be achieved within less than 4 s, and the output stability was improved compared to the case without control strategy.

Heat engine and electric motor torque distribution strategy for a hybrid electric vehicle

DOEpatents

Boberg, Evan S.; Gebby, Brian P.

1999-09-28

A method is provided for controlling a power train system for a hybrid electric vehicle. The method includes a torque distribution strategy for controlling the engine and the electric motor. The engine and motor commands are determined based upon the accelerator position, the battery state of charge and the amount of engine and motor torque available. The amount of torque requested for the engine is restricted by a limited rate of rise in order to reduce the emissions from the engine. The limited engine torque is supplemented by motor torque in order to meet a torque request determined based upon the accelerator position.

Managing motherhood: strategies used by new mothers to maintain perceptions of wellness.

PubMed

Currie, Janet

2009-07-01

The first year or so of motherhood can represent a transitional lifestyle change; however, experiences are not well understood from the mother's own perspective. In a series of interviews, nine mothers related their beliefs and ideas about strategies utilized to maintain a perceived sense of wellness. The mothers used three main strategies: (a) obtaining help, (b) having a plan, and (c) taking time-out. Discovery of a successful strategy lead to a mother feeling greater confidence in the efficacy of her selected method, calmer, and in greater control. In order to achieve a true sense of increasing control over her own health, however, it is recommended a mother prioritize strategies to meet her own personal needs in addition to meeting the needs of others.

New Modulation Method and Control Strategies for Power Electronics Inverters

NASA Astrophysics Data System (ADS)

Aleenejad, Mohsen

The DC to AC power Converters (so-called Inverters) are widely used in industrial applications. The MLIs are becoming increasingly popular in industrial apparatus aimed at medium to high power conversion applications. In comparison to the conventional inverters, they feature superior characteristics such as lower total harmonic distortion (THD), higher efficiency, and lower switching voltage stress. Nevertheless, the superior characteristics come at the price of a more complex topology with an increased number of power electronic switches. The increased number of power electronics switches results in more complicated control strategies for the inverter. Moreover, as the number of power electronic switches increases, the chances of fault occurrence of the switches increases, and thus the inverter's reliability decreases. Due to the extreme monetary ramifications of the interruption of operation in commercial and industrial applications, high reliability for power inverters utilized in these sectors is critical. As a result, developing simple control strategies for normal and fault-tolerant operation of MLIs has always been an interesting topic for researchers in related areas. The purpose of this dissertation is to develop new control and fault-tolerant strategies for the multilevel power inverter. For the normal operation of the inverter, a new high switching frequency technique is developed. The proposed method extends the utilization of the dc link voltage while minimizing the dv/dt of the switches. In the event of a fault, the line voltages of the faulty inverters are unbalanced and cannot be applied to the 3-phase loads. For the faulty condition of the inverter, three novel fault-tolerant techniques are developed. The proposed fault-tolerant strategies generate balanced line voltages without bypassing any healthy and operative inverter element, makes better use of the inverter capacity and generates higher output voltage. These strategies exploit the advantages of the Selective Harmonic Elimination (SHE) and Space Vector Modulation (SVM) methods in conjunction with a slightly modified Fundamental Phase Shift Compensation (FPSC) technique to generate balanced voltages and manipulate voltage harmonics at the same time. The proposed strategies are applicable to several classes of MLIs with three or more voltage levels.

Planner-Based Control of Advanced Life Support Systems

NASA Technical Reports Server (NTRS)

Muscettola, Nicola; Kortenkamp, David; Fry, Chuck; Bell, Scott

2005-01-01

The paper describes an approach to the integration of qualitative and quantitative modeling techniques for advanced life support (ALS) systems. Developing reliable control strategies that scale up to fully integrated life support systems requires augmenting quantitative models and control algorithms with the abstractions provided by qualitative, symbolic models and their associated high-level control strategies. This will allow for effective management of the combinatorics due to the integration of a large number of ALS subsystems. By focusing control actions at different levels of detail and reactivity we can use faster: simpler responses at the lowest level and predictive but complex responses at the higher levels of abstraction. In particular, methods from model-based planning and scheduling can provide effective resource management over long time periods. We describe reference implementation of an advanced control system using the IDEA control architecture developed at NASA Ames Research Center. IDEA uses planning/scheduling as the sole reasoning method for predictive and reactive closed loop control. We describe preliminary experiments in planner-based control of ALS carried out on an integrated ALS simulation developed at NASA Johnson Space Center.

Migratory bird hunter opinions regarding potential management strategies for controlling light goose populations

USGS Publications Warehouse

Dinges, Andrew J.; Webb, Elisabeth B.; Vrtiska, Mark P.; Nilon, Charles H.; Wilhelm Stanis, Sonja A.

2014-01-01

We expanded the Nebraska Light Goose Conservation Order (LGCO) harvest survey (NE, USA) in spring 2012 to assess migratory bird hunter opinions regarding future management strategies for controlling light goose populations. Although hunters strongly agreed that population control of light geese was an important wildlife management issue, they were generally unsupportive of wildlife officials using forms of direct control methods to control light goose populations. Respondents who indicated participation in the 2012 LGCO were also less supportive of any form of direct control compared with migratory bird hunters who did not participate in the LGCO. When presented with alternative methods by wildlife officials for future light goose population control, respondents were most supportive of wildlife agencies selectively shooting light geese on migration and wintering areas and least supportive of wildlife officials using bait with approved chemicals to euthanize light geese. A clear understanding of public perception of various potential direct-control options will likely assist wildlife biologists in making informed decisions on how to proceed with population control of light geese.

Assessment of semi-active friction dampers

NASA Astrophysics Data System (ADS)

dos Santos, Marcelo Braga; Coelho, Humberto Tronconi; Lepore Neto, Francisco Paulo; Mafhoud, Jarir

2017-09-01

The use of friction dampers has been widely proposed for a variety of mechanical systems for which applying viscoelastic materials, fluid based dampers or other viscous dampers is impossible. An important example is the application of friction dampers in aircraft engines to reduce the blades' vibration amplitudes. In most cases, friction dampers have been studied in a passive manner, but significant improvements can be achieved by controlling the normal force in the contact region. The aim of this paper is to present and study five control strategies for friction dampers based on three different hysteresis cycles by using the Harmonic Balance Method (HBM), a numerical and experimental analysis. The first control strategy uses the friction force as a resistance when the system is deviating from its equilibrium position. The second control strategy maximizes the energy removal in each harmonic oscillation cycle by calculating the optimal normal force based on the last displacement peak. The third control strategy combines the first strategy with the homogenous modulation of the friction force. Finally, the last two strategies attempt to predict the system's movement based on its velocity and acceleration and our knowledge of its physical properties. Numerical and experimental studies are performed with these five strategies, which define the performance metrics. The experimental testing rig is fully identified and its parameters are used for numerical simulations. The obtained results show the satisfactory performance of the friction damper and selected strategy and the suitable agreement between the numerical and experimental results.

Postural strategies assessed with inertial sensors in healthy and parkinsonian subjects

PubMed Central

Baston, Chiara; Mancini, Martina; Schoneburg, Bernadette; Horak, Fay; Rocchi, Laura

2015-01-01

The present study introduces a novel instrumented method to characterize postural movement strategies to maintain balance during stance (ankle and hip strategy), by means of inertial sensors, positioned on the legs and on the trunk. We evaluated postural strategies in subjects with2 types of parkinsonism: idiopathic Parkinson's disease (PD) and Progressive Supranuclear Palsy (PSP),and inage-matched control subjects standing under perturbed conditions implementedby the Sensory Organization Test (SOT).Coordination between the upper and lower segments of the body during postural sway was measured using a covariance index over time, by a sliding-window algorithm. Afterwards, a postural strategy index was computed. We also measuredthe amount of postural sway, as adjunctive information to characterize balance, by the root mean square of the horizontal trunk acceleration signal (RMS). Results showed that control subjects were able to change their postural strategy, whilst PSP and PD subjects persisted in use of an ankle strategy in all conditions.PD subjects had RMS values similar to control subjects even without changing postural strategy appropriately, whereas PSP subjects showed much larger RMS values than controls, resulting in several falls during the most challenging SOT conditions (5 and 6). Results are in accordance with the corresponding clinical literature describing postural behavior in the same kind of subjects. The proposed strategy index, based on the use ofinertial sensors on the upper and lower body segments, isa promising and unobtrusive toolto characterize postural strategies performed to attain balance. PMID:24656713

Intelligent automated control of life support systems using proportional representations.

PubMed

Wu, Annie S; Garibay, Ivan I

2004-06-01

Effective automatic control of Advanced Life Support Systems (ALSS) is a crucial component of space exploration. An ALSS is a coupled dynamical system which can be extremely sensitive and difficult to predict. As a result, such systems can be difficult to control using deliberative and deterministic methods. We investigate the performance of two machine learning algorithms, a genetic algorithm (GA) and a stochastic hill-climber (SH), on the problem of learning how to control an ALSS, and compare the impact of two different types of problem representations on the performance of both algorithms. We perform experiments on three ALSS optimization problems using five strategies with multiple variations of a proportional representation for a total of 120 experiments. Results indicate that although a proportional representation can effectively boost GA performance, it does not necessarily have the same effect on other algorithms such as SH. Results also support previous conclusions that multivector control strategies are an effective method for control of coupled dynamical systems.

Coordinated Control of Cross-Flow Turbines

NASA Astrophysics Data System (ADS)

Strom, Benjamin; Brunton, Steven; Polagye, Brian

2016-11-01

Cross-flow turbines, also known as vertical-axis turbines, have several advantages over axial-flow turbines for a number of applications including urban wind power, high-density arrays, and marine or fluvial currents. By controlling the angular velocity applied to the turbine as a function of angular blade position, we have demonstrated a 79 percent increase in cross-flow turbine efficiency over constant-velocity control. This strategy uses the downhill simplex method to optimize control parameter profiles during operation of a model turbine in a recirculating water flume. This optimization method is extended to a set of two turbines, where the blade motions and position of the downstream turbine are optimized to beneficially interact with the coherent structures in the wake of the upstream turbine. This control scheme has the potential to enable high-density arrays of cross-flow turbines to operate at cost-effective efficiency. Turbine wake and force measurements are analyzed for insight into the effect of a coordinated control strategy.

Nonlinear analysis of switched semi-active controlled systems

NASA Astrophysics Data System (ADS)

Eslaminasab, Nima; Vahid A., Orang; Golnaraghi, Farid

2011-02-01

Semi-active systems improve suspension performance of the vehicles more effectively than conventional passive systems by simultaneously improving ride comfort and road handling. Also, because of size, weight, price and performance advantages, they have gained more interest over the active as well as passive systems. Probably the most neglected aspect of the semi-active on-off control systems and strategies is the effects of the added nonlinearities of those systems, which are introduced and analysed in this paper. To do so, numerical techniques, analytical method of averaging and experimental analysis are deployed. In this paper, a new method to analyse, calculate and compare the performances of the semi-active controlled systems is proposed; further, a new controller based on the observations of actual test data is proposed to eliminate the adverse effects of added nonlinearities. The significance of the proposed new system is the simplicity of the algorithm and ease of implementation. In fact, this new semi-active control strategy could be easily adopted and used with most of the existing semi-active control systems.

Sliding Mode Control of Fractional-Order Delayed Memristive Chaotic System with Uncertainty and Disturbance

NASA Astrophysics Data System (ADS)

Ding, Da-Wei; Liu, Fang-Fang; Chen, Hui; Wang, Nian; Liang, Dong

2017-12-01

In this paper, a simplest fractional-order delayed memristive chaotic system is proposed in order to control the chaos behaviors via sliding mode control strategy. Firstly, we design a sliding mode control strategy for the fractional-order system with time delay to make the states of the system asymptotically stable. Then, we obtain theoretical analysis results of the control method using Lyapunov stability theorem which guarantees the asymptotic stability of the non-commensurate order and commensurate order system with and without uncertainty and an external disturbance. Finally, numerical simulations are given to verify that the proposed sliding mode control method can eliminate chaos and stabilize the fractional-order delayed memristive system in a finite time. Supported by the National Nature Science Foundation of China under Grant No. 61201227, Funding of China Scholarship Council, the Natural Science Foundation of Anhui Province under Grant No. 1208085M F93, 211 Innovation Team of Anhui University under Grant Nos. KJTD007A and KJTD001B

A general solution strategy of modified power method for higher mode solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Peng; Lee, Hyunsuk; Lee, Deokjung, E-mail: deokjung@unist.ac.kr

2016-01-15

A general solution strategy of the modified power iteration method for calculating higher eigenmodes has been developed and applied in continuous energy Monte Carlo simulation. The new approach adopts four features: 1) the eigen decomposition of transfer matrix, 2) weight cancellation for higher modes, 3) population control with higher mode weights, and 4) stabilization technique of statistical fluctuations using multi-cycle accumulations. The numerical tests of neutron transport eigenvalue problems successfully demonstrate that the new strategy can significantly accelerate the fission source convergence with stable convergence behavior while obtaining multiple higher eigenmodes at the same time. The advantages of the newmore » strategy can be summarized as 1) the replacement of the cumbersome solution step of high order polynomial equations required by Booth's original method with the simple matrix eigen decomposition, 2) faster fission source convergence in inactive cycles, 3) more stable behaviors in both inactive and active cycles, and 4) smaller variances in active cycles. Advantages 3 and 4 can be attributed to the lower sensitivity of the new strategy to statistical fluctuations due to the multi-cycle accumulations. The application of the modified power method to continuous energy Monte Carlo simulation and the higher eigenmodes up to 4th order are reported for the first time in this paper. -- Graphical abstract: -- Highlights: •Modified power method is applied to continuous energy Monte Carlo simulation. •Transfer matrix is introduced to generalize the modified power method. •All mode based population control is applied to get the higher eigenmodes. •Statistic fluctuation can be greatly reduced using accumulated tally results. •Fission source convergence is accelerated with higher mode solutions.« less

Feedback control methods for drug dosage optimisation. Concepts, classification and clinical application.

PubMed

Vozeh, S; Steimer, J L

1985-01-01

The concept of feedback control methods for drug dosage optimisation is described from the viewpoint of control theory. The control system consists of 5 parts: (a) patient (the controlled process); (b) response (the measured feedback); (c) model (the mathematical description of the process); (d) adaptor (to update the parameters); and (e) controller (to determine optimum dosing strategy). In addition to the conventional distinction between open-loop and closed-loop control systems, a classification is proposed for dosage optimisation techniques which distinguishes between tight-loop and loose-loop methods depending on whether physician's interaction is absent or included as part of the control step. Unlike engineering problems where the process can usually be controlled by fully automated devices, therapeutic situations often require that the physician be included in the decision-making process to determine the 'optimal' dosing strategy. Tight-loop and loose-loop methods can be further divided into adaptive and non-adaptive, depending on the presence of the adaptor. The main application areas of tight-loop feedback control methods are general anaesthesia, control of blood pressure, and insulin delivery devices. Loose-loop feedback methods have been used for oral anticoagulation and in therapeutic drug monitoring. The methodology, advantages and limitations of the different approaches are reviewed. A general feature common to all application areas could be observed: to perform well under routine clinical conditions, which are characterised by large interpatient variability and sometimes also intrapatient changes, control systems should be adaptive. Apart from application in routine drug treatment, feedback control methods represent an important research tool. They can be applied for the investigation of pathophysiological and pharmacodynamic processes. A most promising application is the evaluation of the relationship between an intermediate response (e.g. drug level), which is often used as feedback for dosage adjustment, and the final therapeutic goal.

Development of a fuel cell plug-in hybrid electric vehicle and vehicle simulator for energy management assessment

NASA Astrophysics Data System (ADS)

Meintz, Andrew Lee

This dissertation offers a description of the development of a fuel cell plug-in hybrid electric vehicle focusing on the propulsion architecture selection, propulsion system control, and high-level energy management. Two energy management techniques have been developed and implemented for real-time control of the vehicle. The first method is a heuristic method that relies on a short-term moving average of the vehicle power requirements. The second method utilizes an affine function of the short-term and long-term moving average vehicle power requirements. The development process of these methods has required the creation of a vehicle simulator capable of estimating the effect of changes to the energy management control techniques on the overall vehicle energy efficiency. Furthermore, the simulator has allowed for the refinement of the energy management methods and for the stability of the method to be analyzed prior to on-road testing. This simulator has been verified through on-road testing of a constructed prototype vehicle under both highway and city driving schedules for each energy management method. The results of the finalized vehicle control strategies are compared with the simulator predictions and an assessment of the effectiveness of both strategies is discussed. The methods have been evaluated for energy consumption in the form of both hydrogen fuel and stored electricity from grid charging.

Investigating bang for your training buck: a randomized controlled trial comparing three methods of training clinicians in two core strategies of dialectical behavior therapy.

PubMed

Dimeff, Linda A; Harned, Melanie S; Woodcock, Eric A; Skutch, Julie M; Koerner, Kelly; Linehan, Marsha M

2015-05-01

The present study examined the efficacy of online training (OLT), instructor-led training (ILT), and a treatment manual (TM) in training mental health clinicians in two core strategies of Dialectical Behavior Therapy (DBT): chain analysis and validation. A randomized controlled trial compared OLT, ILT, and TM among clinicians naïve to DBT (N=172) who were assessed at baseline, post-training, and 30, 60, and 90 days following training. Primary outcomes included satisfaction, self-efficacy, motivation, knowledge, clinical proficiency, and clinical use. Overall, ILT outperformed OLT and TM in satisfaction, self-efficacy, and motivation, whereas OLT was the most effective method for increasing knowledge. The conditions did not differ in observer-rated clinical proficiency or self-reported clinical use, which both increased to moderate levels after training. In addition, ILT was particularly effective at improving motivation to use chain analysis, whereas OLT was particularly effective at increasing knowledge of validation strategies. These findings suggest that these types of brief, didactic trainings may be effective methods of increasing knowledge of new treatment strategies, but may not be sufficient to enable clinicians to achieve a high level of clinical use or proficiency. Additional research examining the possible advantages of matching training methods to types of treatment strategies may help to determine a tailored, more effective approach to training clinicians in empirically supported treatments. Copyright © 2015. Published by Elsevier Ltd.

Organizational Culture in Community Colleges: Connecting Market Orientation, Quality, and Student Engagement

ERIC Educational Resources Information Center

McManimon, Debra J.

2012-01-01

To enhance their competitive advantage in the marketplace, many business leaders develop market orientation strategies designed to increase customer engagement. These market orientation strategies include improvement in service delivery, relationship management, customer satisfaction, and quality control methods. There is a lack of understanding…

On Restructurable Control System Theory

NASA Technical Reports Server (NTRS)

Athans, M.

1983-01-01

The state of stochastic system and control theory as it impacts restructurable control issues is addressed. The multivariable characteristics of the control problem are addressed. The failure detection/identification problem is discussed as a multi-hypothesis testing problem. Control strategy reconfiguration, static multivariable controls, static failure hypothesis testing, dynamic multivariable controls, fault-tolerant control theory, dynamic hypothesis testing, generalized likelihood ratio (GLR) methods, and adaptive control are discussed.

Real-time obstacle avoidance using harmonic potential functions

NASA Technical Reports Server (NTRS)

Kim, Jin-Oh; Khosla, Pradeep K.

1992-01-01

This paper presents a new formulation of the artificial potential approach to the obstacle avoidance problem for a mobile robot or a manipulator in a known environment. Previous formulations of artificial potentials for obstacle avoidance have exhibited local minima in a cluttered environment. To build an artificial potential field, harmonic functions that completely eliminate local minima even for a cluttered environment are used. The panel method is employed to represent arbitrarily shaped obstacles and to derive the potential over the whole space. Based on this potential function, an elegant control strategy is proposed for the real-time control of a robot. The harmonic potential, the panel method, and the control strategy are tested with a bar-shaped mobile robot and a three-degree-of-freedom planar redundant manipulator.

Towards a Semantically-Enabled Control Strategy for Building Simulations: Integration of Semantic Technologies and Model Predictive Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delgoshaei, Parastoo; Austin, Mark A.; Pertzborn, Amanda J.

State-of-the-art building simulation control methods incorporate physical constraints into their mathematical models, but omit implicit constraints associated with policies of operation and dependency relationships among rules representing those constraints. To overcome these shortcomings, there is a recent trend in enabling the control strategies with inference-based rule checking capabilities. One solution is to exploit semantic web technologies in building simulation control. Such approaches provide the tools for semantic modeling of domains, and the ability to deduce new information based on the models through use of Description Logic (DL). In a step toward enabling this capability, this paper presents a cross-disciplinary data-drivenmore » control strategy for building energy management simulation that integrates semantic modeling and formal rule checking mechanisms into a Model Predictive Control (MPC) formulation. The results show that MPC provides superior levels of performance when initial conditions and inputs are derived from inference-based rules.« less

Prevention and Control Strategies to Counter Dengue Virus Infection

PubMed Central

Rather, Irfan A.; Parray, Hilal A.; Lone, Jameel B.; Paek, Woon K.; Lim, Jeongheui; Bajpai, Vivek K.; Park, Yong-Ha

2017-01-01

Dengue is currently the highest and rapidly spreading vector-borne viral disease, which can lead to mortality in its severe form. The globally endemic dengue poses as a public health and economic challenge that has been attempted to suppress though application of various prevention and control techniques. Therefore, broad spectrum techniques, that are efficient, cost-effective, and environmentally sustainable, are proposed and practiced in dengue-endemic regions. The development of vaccines and immunotherapies have introduced a new dimension for effective dengue control and prevention. Thus, the present study focuses on the preventive and control strategies that are currently employed to counter dengue. While traditional control strategies bring temporary sustainability alone, implementation of novel biotechnological interventions, such as sterile insect technique, paratransgenesis, and production of genetically modified vectors, has improved the efficacy of the traditional strategies. Although a large-scale vector control strategy can be limited, innovative vaccine candidates have provided evidence for promising dengue prevention measures. The use of tetravalent dengue vaccine (CYD-TDV) has been the most effective so far in treating dengue infections. Nonetheless, challenges and limitation hinder the progress of developing integrated intervention methods and vaccines; while the improvement in the latest techniques and vaccine formulation continues, one can hope for a future without the threat of dengue virus. PMID:28791258

Prevention and Control Strategies to Counter Dengue Virus Infection.

PubMed

Rather, Irfan A; Parray, Hilal A; Lone, Jameel B; Paek, Woon K; Lim, Jeongheui; Bajpai, Vivek K; Park, Yong-Ha

2017-01-01

Dengue is currently the highest and rapidly spreading vector-borne viral disease, which can lead to mortality in its severe form. The globally endemic dengue poses as a public health and economic challenge that has been attempted to suppress though application of various prevention and control techniques. Therefore, broad spectrum techniques, that are efficient, cost-effective, and environmentally sustainable, are proposed and practiced in dengue-endemic regions. The development of vaccines and immunotherapies have introduced a new dimension for effective dengue control and prevention. Thus, the present study focuses on the preventive and control strategies that are currently employed to counter dengue. While traditional control strategies bring temporary sustainability alone, implementation of novel biotechnological interventions, such as sterile insect technique, paratransgenesis, and production of genetically modified vectors, has improved the efficacy of the traditional strategies. Although a large-scale vector control strategy can be limited, innovative vaccine candidates have provided evidence for promising dengue prevention measures. The use of tetravalent dengue vaccine (CYD-TDV) has been the most effective so far in treating dengue infections. Nonetheless, challenges and limitation hinder the progress of developing integrated intervention methods and vaccines; while the improvement in the latest techniques and vaccine formulation continues, one can hope for a future without the threat of dengue virus.

Recent advances in detection and control of infectious hematopoietic necrosis virus in aquaculture

USGS Publications Warehouse

Winton, James R.

1991-01-01

Infectious hematopoietic necrosis (IHN) is one of the most important viral diseases of salmon and trout reared in culture. The disease remains untreatable with avoidance being the only control measure. Much has been learned about the chemical, physical, and serological characteristics of the rhabdovirus causing IHN, but critical gaps exist in our understanding of the biology of the virus in nature. The tools of molecular biology have provided improved methods for detection of pathogens and new strategies for control of viral diseases. This paper reviews several recent improvements in methods for detecting infectious hematopoietic necrosis virus including the application of enzyme-linked immunosorbent assays, development of monoclonal antibodies and DNA probes, and use of the polymerase chain reaction. New strategies for control of IHN through the use of better water treatment, more resistant fish, antiviral drugs or chemicals, and new generation vaccines are discussed.

Tire-road friction estimation and traction control strategy for motorized electric vehicle.

PubMed

Jin, Li-Qiang; Ling, Mingze; Yue, Weiqiang

2017-01-01

In this paper, an optimal longitudinal slip ratio system for real-time identification of electric vehicle (EV) with motored wheels is proposed based on the adhesion between tire and road surface. First and foremost, the optimal longitudinal slip rate torque control can be identified in real time by calculating the derivative and slip rate of the adhesion coefficient. Secondly, the vehicle speed estimation method is also brought. Thirdly, an ideal vehicle simulation model is proposed to verify the algorithm with simulation, and we find that the slip ratio corresponds to the detection of the adhesion limit in real time. Finally, the proposed strategy is applied to traction control system (TCS). The results showed that the method can effectively identify the state of wheel and calculate the optimal slip ratio without wheel speed sensor; in the meantime, it can improve the accelerated stability of electric vehicle with traction control system (TCS).

Tire-road friction estimation and traction control strategy for motorized electric vehicle

PubMed Central

Jin, Li-Qiang; Yue, Weiqiang

2017-01-01

In this paper, an optimal longitudinal slip ratio system for real-time identification of electric vehicle (EV) with motored wheels is proposed based on the adhesion between tire and road surface. First and foremost, the optimal longitudinal slip rate torque control can be identified in real time by calculating the derivative and slip rate of the adhesion coefficient. Secondly, the vehicle speed estimation method is also brought. Thirdly, an ideal vehicle simulation model is proposed to verify the algorithm with simulation, and we find that the slip ratio corresponds to the detection of the adhesion limit in real time. Finally, the proposed strategy is applied to traction control system (TCS). The results showed that the method can effectively identify the state of wheel and calculate the optimal slip ratio without wheel speed sensor; in the meantime, it can improve the accelerated stability of electric vehicle with traction control system (TCS). PMID:28662053

Barrier Function-Based Neural Adaptive Control With Locally Weighted Learning and Finite Neuron Self-Growing Strategy.

PubMed

Jia, Zi-Jun; Song, Yong-Duan

2017-06-01

This paper presents a new approach to construct neural adaptive control for uncertain nonaffine systems. By integrating locally weighted learning with barrier Lyapunov function (BLF), a novel control design method is presented to systematically address the two critical issues in neural network (NN) control field: one is how to fulfill the compact set precondition for NN approximation, and the other is how to use varying rather than a fixed NN structure to improve the functionality of NN control. A BLF is exploited to ensure the NN inputs to remain bounded during the entire system operation. To account for system nonlinearities, a neuron self-growing strategy is proposed to guide the process for adding new neurons to the system, resulting in a self-adjustable NN structure for better learning capabilities. It is shown that the number of neurons needed to accomplish the control task is finite, and better performance can be obtained with less number of neurons as compared with traditional methods. The salient feature of the proposed method also lies in the continuity of the control action everywhere. Furthermore, the resulting control action is smooth almost everywhere except for a few time instants at which new neurons are added. Numerical example illustrates the effectiveness of the proposed approach.

A dual-loop adaptive control for minimizing time response delay in real-time structural vibration control with magnetorheological (MR) devices

NASA Astrophysics Data System (ADS)

Chen, Xi; Li, Yancheng; Li, Jianchun; Gu, Xiaoyu

2018-01-01

Time delay is a challenge issue faced by the real-time control application of the magnetorheological (MR) devices. Not to deal with it properly may jeopardize the effectiveness of the control, even lead to instability of the control system or catastrophic failure. This paper proposes a dual-loop adaptive control to address the response time delay associated with MR devices. In the proposed dual-loop control, the inner loop is designed to compensate the time delay of MR device induced by the PWM current driver. While the outer loop control can be any structural control algorithm with aims to reducing structural responses of a building during extreme loadings. Here an adaptive control strategy is adopted. To verify the proposed dual-loop control, a smart base isolation system employing magnetorheological elastomer base isolators is used as an example to illustrate the control effect. Numerical study is then conducted using a 5 -storey shear building model equipped with smart base isolation system. The result shows that with the implementation of the inner loop, the control current can instantly follow the control command which reduce the possibility of instability caused by the time delay. Comparative studies are conducted between three control strategies, i.e. dual-loop control, Lyapunov’s direct method based control and optimal passive base isolation control. The results of the study have demonstrated that the proposed dual-loop control strategy can achieve much better performance than the other two control strategies.

Reliability of unstable periodic orbit based control strategies in biological systems.

PubMed

Mishra, Nagender; Hasse, Maria; Biswal, B; Singh, Harinder P

2015-04-01

Presence of recurrent and statistically significant unstable periodic orbits (UPOs) in time series obtained from biological systems is now routinely used as evidence for low dimensional chaos. Extracting accurate dynamical information from the detected UPO trajectories is vital for successful control strategies that either aim to stabilize the system near the fixed point or steer the system away from the periodic orbits. A hybrid UPO detection method from return maps that combines topological recurrence criterion, matrix fit algorithm, and stringent criterion for fixed point location gives accurate and statistically significant UPOs even in the presence of significant noise. Geometry of the return map, frequency of UPOs visiting the same trajectory, length of the data set, strength of the noise, and degree of nonstationarity affect the efficacy of the proposed method. Results suggest that establishing determinism from unambiguous UPO detection is often possible in short data sets with significant noise, but derived dynamical properties are rarely accurate and adequate for controlling the dynamics around these UPOs. A repeat chaos control experiment on epileptic hippocampal slices through more stringent control strategy and adaptive UPO tracking is reinterpreted in this context through simulation of similar control experiments on an analogous but stochastic computer model of epileptic brain slices. Reproduction of equivalent results suggests that far more stringent criteria are needed for linking apparent success of control in such experiments with possible determinism in the underlying dynamics.

Discussion and Practical Aspects on Control Allocation for a Multi-Rotor Helicopter

NASA Astrophysics Data System (ADS)

Ducard, G. J. J.; Hua, M.-D.

2011-09-01

This paper presents practical methods to improve the flight performance of an unmanned multi-rotor helicopter by using an efficient control allocation strategy. The flying vehicle considered is an hexacopter. It is indeed particularly suited for long missions and for carrying a significant payload such as all the sensors needed in the context of cartography, photogrammetry, inspection, surveillance and transportation. Moreover, a stable flight is often required for precise data recording during the mission. Therefore, a high performance flight control system is required to operate the UAV. However, the flight performance of a multi-rotor vehicle is tightly dependent on the control allocation strategy that is used to map the virtual control vector v = [T, L, M, N ]T composed of the thrust and the torques in roll, pitch and yaw, respectively, to the propellers' speed. This paper shows that a control allocation strategy based on the classical approach of pseudo-inverse matrix only exploits a limited range of the vehicle capabilities to generate thrust and moments. Thus, in this paper, a novel approach is presented, which is based on a weighted pseudo-inverse matrix method capable of exploiting a much larger domain in v. The proposed control allocation algorithm is designed with explicit laws for fast operation and low computational load, suitable for a small microcontroller with limited floating-point operation capability.

Coordinated Control Strategy of a Battery Energy Storage System to Support a Wind Power Plant Providing Multi-Timescale Frequency Ancillary Services

DOE PAGES

Tan, Jin; Zhang, Yingchen

2017-02-02

With increasing penetrations of wind generation on electric grids, wind power plants (WPPs) are encouraged to provide frequency ancillary services (FAS); however, it is a challenge to ensure that variable wind generation can reliably provide these ancillary services. This paper proposes using a battery energy storage system (BESS) to ensure the WPPs' commitment to FAS. This method also focuses on reducing the BESS's size and extending its lifetime. In this paper, a state-machine-based coordinated control strategy is developed to utilize a BESS to support the obliged FAS of a WPP (including both primary and secondary frequency control). This method takesmore » into account the operational constraints of the WPP (e.g., real-time reserve) and the BESS (e.g., state of charge [SOC], charge and discharge rate) to provide reliable FAS. Meanwhile, an adaptive SOC-feedback control is designed to maintain SOC at the optimal value as much as possible and thus reduce the size and extend the lifetime of the BESS. In conclusion, the effectiveness of the control strategy is validated with an innovative, multi-area, interconnected power system simulation platform that can mimic realistic power systems operation and control by simulating real-time economic dispatch, regulating reserve scheduling, multi-area automatic generation control, and generators' dynamic response.« less

Coordinated Control Strategy of a Battery Energy Storage System to Support a Wind Power Plant Providing Multi-Timescale Frequency Ancillary Services

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Jin; Zhang, Yingchen

With increasing penetrations of wind generation on electric grids, wind power plants (WPPs) are encouraged to provide frequency ancillary services (FAS); however, it is a challenge to ensure that variable wind generation can reliably provide these ancillary services. This paper proposes using a battery energy storage system (BESS) to ensure the WPPs' commitment to FAS. This method also focuses on reducing the BESS's size and extending its lifetime. In this paper, a state-machine-based coordinated control strategy is developed to utilize a BESS to support the obliged FAS of a WPP (including both primary and secondary frequency control). This method takesmore » into account the operational constraints of the WPP (e.g., real-time reserve) and the BESS (e.g., state of charge [SOC], charge and discharge rate) to provide reliable FAS. Meanwhile, an adaptive SOC-feedback control is designed to maintain SOC at the optimal value as much as possible and thus reduce the size and extend the lifetime of the BESS. In conclusion, the effectiveness of the control strategy is validated with an innovative, multi-area, interconnected power system simulation platform that can mimic realistic power systems operation and control by simulating real-time economic dispatch, regulating reserve scheduling, multi-area automatic generation control, and generators' dynamic response.« less

Reliability of unstable periodic orbit based control strategies in biological systems

NASA Astrophysics Data System (ADS)

Mishra, Nagender; Hasse, Maria; Biswal, B.; Singh, Harinder P.

2015-04-01

Presence of recurrent and statistically significant unstable periodic orbits (UPOs) in time series obtained from biological systems is now routinely used as evidence for low dimensional chaos. Extracting accurate dynamical information from the detected UPO trajectories is vital for successful control strategies that either aim to stabilize the system near the fixed point or steer the system away from the periodic orbits. A hybrid UPO detection method from return maps that combines topological recurrence criterion, matrix fit algorithm, and stringent criterion for fixed point location gives accurate and statistically significant UPOs even in the presence of significant noise. Geometry of the return map, frequency of UPOs visiting the same trajectory, length of the data set, strength of the noise, and degree of nonstationarity affect the efficacy of the proposed method. Results suggest that establishing determinism from unambiguous UPO detection is often possible in short data sets with significant noise, but derived dynamical properties are rarely accurate and adequate for controlling the dynamics around these UPOs. A repeat chaos control experiment on epileptic hippocampal slices through more stringent control strategy and adaptive UPO tracking is reinterpreted in this context through simulation of similar control experiments on an analogous but stochastic computer model of epileptic brain slices. Reproduction of equivalent results suggests that far more stringent criteria are needed for linking apparent success of control in such experiments with possible determinism in the underlying dynamics.

Modeling strategies for pharmaceutical blend monitoring and end-point determination by near-infrared spectroscopy.

PubMed

Igne, Benoît; de Juan, Anna; Jaumot, Joaquim; Lallemand, Jordane; Preys, Sébastien; Drennen, James K; Anderson, Carl A

2014-10-01

The implementation of a blend monitoring and control method based on a process analytical technology such as near infrared spectroscopy requires the selection and optimization of numerous criteria that will affect the monitoring outputs and expected blend end-point. Using a five component formulation, the present article contrasts the modeling strategies and end-point determination of a traditional quantitative method based on the prediction of the blend parameters employing partial least-squares regression with a qualitative strategy based on principal component analysis and Hotelling's T(2) and residual distance to the model, called Prototype. The possibility to monitor and control blend homogeneity with multivariate curve resolution was also assessed. The implementation of the above methods in the presence of designed experiments (with variation of the amount of active ingredient and excipients) and with normal operating condition samples (nominal concentrations of the active ingredient and excipients) was tested. The impact of criteria used to stop the blends (related to precision and/or accuracy) was assessed. Results demonstrated that while all methods showed similarities in their outputs, some approaches were preferred for decision making. The selectivity of regression based methods was also contrasted with the capacity of qualitative methods to determine the homogeneity of the entire formulation. Copyright © 2014. Published by Elsevier B.V.

Analysis of pilot control strategy

NASA Technical Reports Server (NTRS)

Heffley, R. K.; Hanson, G. D.; Jewell, W. F.; Clement, W. F.

1983-01-01

Methods for nonintrusive identification of pilot control strategy and task execution dynamics are presented along with examples based on flight data. The specific analysis technique is Nonintrusive Parameter Identification Procedure (NIPIP), which is described in a companion user's guide (NASA CR-170398). Quantification of pilot control strategy and task execution dynamics is discussed in general terms followed by a more detailed description of how NIPIP can be applied. The examples are based on flight data obtained from the NASA F-8 digital fly by wire airplane. These examples involve various piloting tasks and control axes as well as a demonstration of how the dynamics of the aircraft itself are identified using NIPIP. Application of NIPIP to the AFTI/F-16 flight test program is discussed. Recommendations are made for flight test applications in general and refinement of NIPIP to include interactive computer graphics.

An Examination of Strategy Implementation during Abstract Nonlinguistic Category Learning in Aphasia

ERIC Educational Resources Information Center

Vallila-Rohter, Sofia; Kiran, Swathi

2015-01-01

Purpose: Our purpose was to study strategy use during nonlinguistic category learning in aphasia. Method: Twelve control participants without aphasia and 53 participants with aphasia (PWA) completed a computerized feedback-based category learning task consisting of training and testing phases. Accuracy rates of categorization in testing phases…

Affective Cues and Processing Strategy: Color-Coded Examination Forms Influence Performance.

ERIC Educational Resources Information Center

Sinclair, Robert C.; Soldat, Alexander S.; Mark, Melvin M.

1998-01-01

Argues that external cues provide affective information that influence processing strategy and, therefore, examination performance. Notes the differences in performance for two midterm examinations, identical, except that they were printed on blue and red paper. Discusses a method for appropriately adjusting scores to control for form effects.…

A method to simulate motor control strategies to recover from perturbations: application to a stumble recovery during gait.

PubMed

Forner-Cordero, Arturo; Ackermann, Marko; de Lima Freitas, Mateus

2011-01-01

Perturbations during human gait such as a trip or a slip can result in a fall, especially among frail populations such as the elderly. In order to recover from a trip or a stumble during gait, humans perform different types of recovery strategies. It is very useful to uncover the mechanisms of the recovery to improve training methods for populations at risk of falling. Moreover, human recovery strategies could be applied to implement controllers for bipedal robot walker, as an application of biomimetic design. A biomechanical model of the response to a trip during gait might uncover the control mechanisms underlying the different recovery strategies and the adaptation of the responses found during the execution of successive perturbation trials. This paper introduces a model of stumble in the multibody system framework. This model is used to assess different feedforward strategies to recover from a trip. First of all, normal gait patterns for the musculoskeletal system model are obtained by solving an optimal control problem. Secondly, the reference gait is perturbed by the application of forces on the swinging foot in different ways: as an instantaneous inelastic collision of the foot with an obstacle, as an impulsive horizontal force or using a force curve measured experimentally during gait perturbation experiments. The influence of the type of perturbation, the timing of the collision with respect to the gait cycle, as well as of the coefficient of restitution was investigated previously. Finally, in order to test the effects of different muscle excitation levels on the initial phases of the recovery response, several muscle excitations were added to selected muscles of the legs, thus providing a simulation of the recovery reactions. These results pave the way for future analysis and modeling of the control mechanisms of gait.

Combustion Control System Design of Diesel Engine via ASPR based Output Feedback Control Strategy with a PFC

NASA Astrophysics Data System (ADS)

Mizumoto, Ikuro; Tsunematsu, Junpei; Fujii, Seiya

2016-09-01

In this paper, a design method of an output feedback control system with a simple feedforward input for a combustion model of diesel engine will be proposed based on the almost strictly positive real-ness (ASPR-ness) of the controlled system for a combustion control of diesel engines. A parallel feedforward compensator (PFC) design scheme which renders the resulting augmented controlled system ASPR will also be proposed in order to design a stable output feedback control system for the considered combustion model. The effectiveness of our proposed method will be confirmed through numerical simulations.

A switching formation strategy for obstacle avoidance of a multi-robot system based on robot priority model.

PubMed

Dai, Yanyan; Kim, YoonGu; Wee, SungGil; Lee, DongHa; Lee, SukGyu

2015-05-01

This paper describes a switching formation strategy for multi-robots with velocity constraints to avoid and cross obstacles. In the strategy, a leader robot plans a safe path using the geometric obstacle avoidance control method (GOACM). By calculating new desired distances and bearing angles with the leader robot, the follower robots switch into a safe formation. With considering collision avoidance, a novel robot priority model, based on the desired distance and bearing angle between the leader and follower robots, is designed during the obstacle avoidance process. The adaptive tracking control algorithm guarantees that the trajectory and velocity tracking errors converge to zero. To demonstrate the validity of the proposed methods, simulation and experiment results present that multi-robots effectively form and switch formation avoiding obstacles without collisions. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Optimal subhourly electricity resource dispatch under multiple price signals with high renewable generation availability

DOE PAGES

Chassin, David P.; Behboodi, Sahand; Djilali, Ned

2018-01-28

This article proposes a system-wide optimal resource dispatch strategy that enables a shift from a primarily energy cost-based approach, to a strategy using simultaneous price signals for energy, power and ramping behavior. A formal method to compute the optimal sub-hourly power trajectory is derived for a system when the price of energy and ramping are both significant. Optimal control functions are obtained in both time and frequency domains, and a discrete-time solution suitable for periodic feedback control systems is presented. The method is applied to North America Western Interconnection for the planning year 2024, and it is shown that anmore » optimal dispatch strategy that simultaneously considers both the cost of energy and the cost of ramping leads to significant cost savings in systems with high levels of renewable generation: the savings exceed 25% of the total system operating cost for a 50% renewables scenario.« less

Efficient estimation of the maximum metabolic productivity of batch systems

DOE PAGES

St. John, Peter C.; Crowley, Michael F.; Bomble, Yannick J.

2017-01-31

Production of chemicals from engineered organisms in a batch culture involves an inherent trade-off between productivity, yield, and titer. Existing strategies for strain design typically focus on designing mutations that achieve the highest yield possible while maintaining growth viability. While these methods are computationally tractable, an optimum productivity could be achieved by a dynamic strategy in which the intracellular division of resources is permitted to change with time. New methods for the design and implementation of dynamic microbial processes, both computational and experimental, have therefore been explored to maximize productivity. However, solving for the optimal metabolic behavior under the assumptionmore » that all fluxes in the cell are free to vary is a challenging numerical task. Here, previous studies have therefore typically focused on simpler strategies that are more feasible to implement in practice, such as the time-dependent control of a single flux or control variable.« less

Optimal subhourly electricity resource dispatch under multiple price signals with high renewable generation availability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chassin, David P.; Behboodi, Sahand; Djilali, Ned

This article proposes a system-wide optimal resource dispatch strategy that enables a shift from a primarily energy cost-based approach, to a strategy using simultaneous price signals for energy, power and ramping behavior. A formal method to compute the optimal sub-hourly power trajectory is derived for a system when the price of energy and ramping are both significant. Optimal control functions are obtained in both time and frequency domains, and a discrete-time solution suitable for periodic feedback control systems is presented. The method is applied to North America Western Interconnection for the planning year 2024, and it is shown that anmore » optimal dispatch strategy that simultaneously considers both the cost of energy and the cost of ramping leads to significant cost savings in systems with high levels of renewable generation: the savings exceed 25% of the total system operating cost for a 50% renewables scenario.« less

Escherichia coli O157:H7 in beef cattle: on farm contamination and pre-slaughter control methods.

PubMed

Soon, J M; Chadd, S A; Baines, R N

2011-12-01

This paper addresses food safety in beef cattle production, with particular emphasis on factors that affect the prevalence of Escherichia coli O157:H7 in beef cattle and on control methods that have been investigated. Product recalls and foodborne diseases due to this organism continue to occur even though control measures have been under investigation for over 20 years. Most meatborne outbreaks are due to improper food handling practices and consumption of undercooked meat. However, the majority of pathogenic bacteria that can spread at slaughter by cross-contamination can be traced back to the farm rather than originating from the slaughter plant. This would ideally require the adoption of rigorous on-farm intervention strategies to mitigate risks at the farm level. On-farm strategies to control and reduce E. coli O157:H7 at the farm level will reduce the risk of carcass contamination at slaughter and processing facilities although they will not eliminate E. coli O157:H7. The most successful strategy for reducing the risk of contamination of beef and beef products will involve the implementation of both pre- and post-harvest measures.

A mixed methods multiple case study of implementation as usual in children’s social service organizations: study protocol

PubMed Central

2013-01-01

Background Improving quality in children’s mental health and social service settings will require implementation strategies capable of moving effective treatments and other innovations (e.g., assessment tools) into routine care. It is likely that efforts to identify, develop, and refine implementation strategies will be more successful if they are informed by relevant stakeholders and are responsive to the strengths and limitations of the contexts and implementation processes identified in usual care settings. This study will describe: the types of implementation strategies used; how organizational leaders make decisions about what to implement and how to approach the implementation process; organizational stakeholders’ perceptions of different implementation strategies; and the potential influence of organizational culture and climate on implementation strategy selection, implementation decision-making, and stakeholders’ perceptions of implementation strategies. Methods/design This study is a mixed methods multiple case study of seven children’s social service organizations in one Midwestern city in the United States that compose the control group of a larger randomized controlled trial. Qualitative data will include semi-structured interviews with organizational leaders (e.g., CEOs/directors, clinical directors, program managers) and a review of documents (e.g., implementation and quality improvement plans, program manuals, etc.) that will shed light on implementation decision-making and specific implementation strategies that are used to implement new programs and practices. Additionally, focus groups with clinicians will explore their perceptions of a range of implementation strategies. This qualitative work will inform the development of a Web-based survey that will assess the perceived effectiveness, relative importance, acceptability, feasibility, and appropriateness of implementation strategies from the perspective of both clinicians and organizational leaders. Finally, the Organizational Social Context measure will be used to assess organizational culture and climate. Qualitative, quantitative, and mixed methods data will be analyzed and interpreted at the case level as well as across cases in order to highlight meaningful similarities, differences, and site-specific experiences. Discussion This study is designed to inform efforts to develop more effective implementation strategies by fully describing the implementation experiences of a sample of community-based organizations that provide mental health services to youth in one Midwestern city. PMID:23961701

OMICS-strategies and methods in the fight against doping.

PubMed

Reichel, Christian

2011-12-10

During the past decade OMICS-methods not only continued to have their impact on research strategies in life sciences and in particular molecular biology, but also started to be used for anti-doping control purposes. Research activities were mainly reasoned by the fact that several substances and methods, which were prohibited by the World Anti-Doping Agency (WADA), were or still are difficult to detect by direct methods. Transcriptomics, proteomics, and metabolomics in theory offer ideal platforms for the discovery of biomarkers for the indirect detection of the abuse of these substances and methods. Traditionally, the main focus of transcriptomics and proteomics projects has been on the prolonged detection of the misuse of human growth hormone (hGH), recombinant erythropoietin (rhEpo), and autologous blood transfusion. An additional benefit of the indirect or marker approach would also be that similarly acting substances might then be detected by a single method, without being forced to develop new direct detection methods for new but comparable prohibited substances (as has been the case, e.g. for the various forms of Epo analogs and biosimilars). While several non-OMICS-derived parameters for the indirect detection of doping are currently in use, for example the blood parameters of the hematological module of the athlete's biological passport, the outcome of most non-targeted OMICS-projects led to no direct application in routine doping control so far. The main reason is the inherent complexity of human transcriptomes, proteomes, and metabolomes and their inter-individual variability. The article reviews previous and recent research projects and their results and discusses future strategies for a more efficient application of OMICS-methods in doping control. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Optimal control of an invasive species using a reaction-diffusion model and linear programming

USGS Publications Warehouse

Bonneau, Mathieu; Johnson, Fred A.; Smith, Brian J.; Romagosa, Christina M.; Martin, Julien; Mazzotti, Frank J.

2017-01-01

Managing an invasive species is particularly challenging as little is generally known about the species’ biological characteristics in its new habitat. In practice, removal of individuals often starts before the species is studied to provide the information that will later improve control. Therefore, the locations and the amount of control have to be determined in the face of great uncertainty about the species characteristics and with a limited amount of resources. We propose framing spatial control as a linear programming optimization problem. This formulation, paired with a discrete reaction-diffusion model, permits calculation of an optimal control strategy that minimizes the remaining number of invaders for a fixed cost or that minimizes the control cost for containment or protecting specific areas from invasion. We propose computing the optimal strategy for a range of possible model parameters, representing current uncertainty on the possible invasion scenarios. Then, a best strategy can be identified depending on the risk attitude of the decision-maker. We use this framework to study the spatial control of the Argentine black and white tegus (Salvator merianae) in South Florida. There is uncertainty about tegu demography and we considered several combinations of model parameters, exhibiting various dynamics of invasion. For a fixed one-year budget, we show that the risk-averse strategy, which optimizes the worst-case scenario of tegus’ dynamics, and the risk-neutral strategy, which optimizes the expected scenario, both concentrated control close to the point of introduction. A risk-seeking strategy, which optimizes the best-case scenario, focuses more on models where eradication of the species in a cell is possible and consists of spreading control as much as possible. For the establishment of a containment area, assuming an exponential growth we show that with current control methods it might not be possible to implement such a strategy for some of the models that we considered. Including different possible models allows an examination of how the strategy is expected to perform in different scenarios. Then, a strategy that accounts for the risk attitude of the decision-maker can be designed.

Dynamics and control of DNA sequence amplification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marimuthu, Karthikeyan; Chakrabarti, Raj, E-mail: raj@pmc-group.com, E-mail: rajc@andrew.cmu.edu; Division of Fundamental Research, PMC Advanced Technology, Mount Laurel, New Jersey 08054

2014-10-28

DNA amplification is the process of replication of a specified DNA sequence in vitro through time-dependent manipulation of its external environment. A theoretical framework for determination of the optimal dynamic operating conditions of DNA amplification reactions, for any specified amplification objective, is presented based on first-principles biophysical modeling and control theory. Amplification of DNA is formulated as a problem in control theory with optimal solutions that can differ considerably from strategies typically used in practice. Using the Polymerase Chain Reaction as an example, sequence-dependent biophysical models for DNA amplification are cast as control systems, wherein the dynamics of the reactionmore » are controlled by a manipulated input variable. Using these control systems, we demonstrate that there exists an optimal temperature cycling strategy for geometric amplification of any DNA sequence and formulate optimal control problems that can be used to derive the optimal temperature profile. Strategies for the optimal synthesis of the DNA amplification control trajectory are proposed. Analogous methods can be used to formulate control problems for more advanced amplification objectives corresponding to the design of new types of DNA amplification reactions.« less

A compatible control algorithm for greenhouse environment control based on MOCC strategy.

PubMed

Hu, Haigen; Xu, Lihong; Zhu, Bingkun; Wei, Ruihua

2011-01-01

Conventional methods used for solving greenhouse environment multi-objective conflict control problems lay excessive emphasis on control performance and have inadequate consideration for both energy consumption and special requirements for plant growth. The resulting solution will cause higher energy cost. However, during the long period of work and practice, we find that it may be more reasonable to adopt interval or region control objectives instead of point control objectives. In this paper, we propose a modified compatible control algorithm, and employ Multi-Objective Compatible Control (MOCC) strategy and an extant greenhouse model to achieve greenhouse climate control based on feedback control architecture. A series of simulation experiments through various comparative studies are presented to validate the feasibility of the proposed algorithm. The results are encouraging and suggest the energy-saving application to real-world engineering problems in greenhouse production. It may be valuable and helpful to formulate environmental control strategies, and to achieve high control precision and low energy cost for real-world engineering application in greenhouse production. Moreover, the proposed approach has also potential to be useful for other practical control optimization problems with the features like the greenhouse environment control system.

A Compatible Control Algorithm for Greenhouse Environment Control Based on MOCC Strategy

PubMed Central

Hu, Haigen; Xu, Lihong; Zhu, Bingkun; Wei, Ruihua

2011-01-01

Conventional methods used for solving greenhouse environment multi-objective conflict control problems lay excessive emphasis on control performance and have inadequate consideration for both energy consumption and special requirements for plant growth. The resulting solution will cause higher energy cost. However, during the long period of work and practice, we find that it may be more reasonable to adopt interval or region control objectives instead of point control objectives. In this paper, we propose a modified compatible control algorithm, and employ Multi-Objective Compatible Control (MOCC) strategy and an extant greenhouse model to achieve greenhouse climate control based on feedback control architecture. A series of simulation experiments through various comparative studies are presented to validate the feasibility of the proposed algorithm. The results are encouraging and suggest the energy-saving application to real-world engineering problems in greenhouse production. It may be valuable and helpful to formulate environmental control strategies, and to achieve high control precision and low energy cost for real-world engineering application in greenhouse production. Moreover, the proposed approach has also potential to be useful for other practical control optimization problems with the features like the greenhouse environment control system. PMID:22163799

One shot methods for optimal control of distributed parameter systems 1: Finite dimensional control

NASA Technical Reports Server (NTRS)

Taasan, Shlomo

1991-01-01

The efficient numerical treatment of optimal control problems governed by elliptic partial differential equations (PDEs) and systems of elliptic PDEs, where the control is finite dimensional is discussed. Distributed control as well as boundary control cases are discussed. The main characteristic of the new methods is that they are designed to solve the full optimization problem directly, rather than accelerating a descent method by an efficient multigrid solver for the equations involved. The methods use the adjoint state in order to achieve efficient smoother and a robust coarsening strategy. The main idea is the treatment of the control variables on appropriate scales, i.e., control variables that correspond to smooth functions are solved for on coarse grids depending on the smoothness of these functions. Solution of the control problems is achieved with the cost of solving the constraint equations about two to three times (by a multigrid solver). Numerical examples demonstrate the effectiveness of the method proposed in distributed control case, pointwise control and boundary control problems.

Rationale for classical biological control of cattle fever ticks and proposed methods for field collection of natural enemies

USDA-ARS?s Scientific Manuscript database

Classical biological control using specialist parasitoids, predators and/or nematodes from the native ranges of cattle fever ticks Rhipicephalus microplus and Rhipicephalus annulatus could complement existing control strategies for this livestock pest in the transboundary region between Mexico and T...

Constrained tracking control for nonlinear systems.

PubMed

Khani, Fatemeh; Haeri, Mohammad

2017-09-01

This paper proposes a tracking control strategy for nonlinear systems without needing a prior knowledge of the reference trajectory. The proposed method consists of a set of local controllers with appropriate overlaps in their stability regions and an on-line switching strategy which implements these controllers and uses some augmented intermediate controllers to ensure steering the system states to the desired set points without needing to redesign the controller for each value of set point changes. The proposed approach provides smooth transient responses despite switching among the local controllers. It should be mentioned that the stability regions of the proposed controllers could be estimated off-line for a range of set-point changes. The efficiencies of the proposed algorithm are illustrated via two example simulations. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Model-free adaptive sliding mode controller design for generalized projective synchronization of the fractional-order chaotic system via radial basis function neural networks

NASA Astrophysics Data System (ADS)

Wang, L. M.

2017-09-01

A novel model-free adaptive sliding mode strategy is proposed for a generalized projective synchronization (GPS) between two entirely unknown fractional-order chaotic systems subject to the external disturbances. To solve the difficulties from the little knowledge about the master-slave system and to overcome the bad effects of the external disturbances on the generalized projective synchronization, the radial basis function neural networks are used to approach the packaged unknown master system and the packaged unknown slave system (including the external disturbances). Consequently, based on the slide mode technology and the neural network theory, a model-free adaptive sliding mode controller is designed to guarantee asymptotic stability of the generalized projective synchronization error. The main contribution of this paper is that a control strategy is provided for the generalized projective synchronization between two entirely unknown fractional-order chaotic systems subject to the unknown external disturbances, and the proposed control strategy only requires that the master system has the same fractional orders as the slave system. Moreover, the proposed method allows us to achieve all kinds of generalized projective chaos synchronizations by turning the user-defined parameters onto the desired values. Simulation results show the effectiveness of the proposed method and the robustness of the controlled system.

Likelihood of achieving air quality targets under model uncertainties.

PubMed

Digar, Antara; Cohan, Daniel S; Cox, Dennis D; Kim, Byeong-Uk; Boylan, James W

2011-01-01

Regulatory attainment demonstrations in the United States typically apply a bright-line test to predict whether a control strategy is sufficient to attain an air quality standard. Photochemical models are the best tools available to project future pollutant levels and are a critical part of regulatory attainment demonstrations. However, because photochemical models are uncertain and future meteorology is unknowable, future pollutant levels cannot be predicted perfectly and attainment cannot be guaranteed. This paper introduces a computationally efficient methodology for estimating the likelihood that an emission control strategy will achieve an air quality objective in light of uncertainties in photochemical model input parameters (e.g., uncertain emission and reaction rates, deposition velocities, and boundary conditions). The method incorporates Monte Carlo simulations of a reduced form model representing pollutant-precursor response under parametric uncertainty to probabilistically predict the improvement in air quality due to emission control. The method is applied to recent 8-h ozone attainment modeling for Atlanta, Georgia, to assess the likelihood that additional controls would achieve fixed (well-defined) or flexible (due to meteorological variability and uncertain emission trends) targets of air pollution reduction. The results show that in certain instances ranking of the predicted effectiveness of control strategies may differ between probabilistic and deterministic analyses.

Multi-Criteria Decision Making Approaches for Quality Control of Genome-Wide Association Studies

PubMed Central

Malovini, Alberto; Rognoni, Carla; Puca, Annibale; Bellazzi, Riccardo

2009-01-01

Experimental errors in the genotyping phases of a Genome-Wide Association Study (GWAS) can lead to false positive findings and to spurious associations. An appropriate quality control phase could minimize the effects of this kind of errors. Several filtering criteria can be used to perform quality control. Currently, no formal methods have been proposed for taking into account at the same time these criteria and the experimenter’s preferences. In this paper we propose two strategies for setting appropriate genotyping rate thresholds for GWAS quality control. These two approaches are based on the Multi-Criteria Decision Making theory. We have applied our method on a real dataset composed by 734 individuals affected by Arterial Hypertension (AH) and 486 nonagenarians without history of AH. The proposed strategies appear to deal with GWAS quality control in a sound way, as they lead to rationalize and make explicit the experimenter’s choices thus providing more reproducible results. PMID:21347174

Modelling malaria control by introduction of larvivorous fish.

PubMed

Lou, Yijun; Zhao, Xiao-Qiang

2011-10-01

Malaria creates serious health and economic problems which call for integrated management strategies to disrupt interactions among mosquitoes, the parasite and humans. In order to reduce the intensity of malaria transmission, malaria vector control may be implemented to protect individuals against infective mosquito bites. As a sustainable larval control method, the use of larvivorous fish is promoted in some circumstances. To evaluate the potential impacts of this biological control measure on malaria transmission, we propose and investigate a mathematical model describing the linked dynamics between the host-vector interaction and the predator-prey interaction. The model, which consists of five ordinary differential equations, is rigorously analysed via theories and methods of dynamical systems. We derive four biologically plausible and insightful quantities (reproduction numbers) that completely determine the community composition. Our results suggest that the introduction of larvivorous fish can, in principle, have important consequences for malaria dynamics, but also indicate that this would require strong predators on larval mosquitoes. Integrated strategies of malaria control are analysed to demonstrate the biological application of our developed theory.

Vibration control in smart coupled beams subjected to pulse excitations

NASA Astrophysics Data System (ADS)

Pisarski, Dominik; Bajer, Czesław I.; Dyniewicz, Bartłomiej; Bajkowski, Jacek M.

2016-10-01

In this paper, a control method to stabilize the vibration of adjacent structures is presented. The control is realized by changes of the stiffness parameters of the structure's couplers. A pulse excitation applied to the coupled adjacent beams is imposed as the kinematic excitation. For such a representation, the designed control law provides the best rate of energy dissipation. By means of a stability analysis, the performance in different structural settings is studied. The efficiency of the proposed strategy is examined via numerical simulations. In terms of the assumed energy metric, the controlled structure outperforms its passively damped equivalent by over 50 percent. The functionality of the proposed control strategy should attract the attention of practising engineers who seek solutions to upgrade existing damping systems.

Detumbling control for kinematically redundant space manipulator post-grasping a rotational satellite

NASA Astrophysics Data System (ADS)

Wang, Mingming; Luo, Jianjun; Yuan, Jianping; Walter, Ulrich

2017-12-01

The objective of this paper is to establish a detumbling strategy and a coordination control scheme for a kinematically redundant space manipulator post-grasping a rotational satellite. First, the dynamics of the kinematically redundant space robot after grasping the target is presented, which lays the foundation for the coordination controller design. Subsequently, optimal detumbling and motion planning strategy for the post-capture phase is proposed based on the quartic Bézier curves and adaptive differential evolution (DE) algorithm subject to the specific constraints. Both detumbling time and control torques are taken into account for the generation of the optimal detumbling strategy. Furthermore, a coordination control scheme is presented to track the designed reference path while regulating the attitude of the chaser to a desired value, which successfully dumps the initial angular velocity of the rotational satellite and controls the base attitude synchronously. Simulation results are presented for detumbling a target with rotational motion using a 7 degree-of-freedom (DOF) redundant space manipulator, which demonstrates the effectiveness of the proposed method.

Malaria in Sucre State, Venezuela.

PubMed

Zimmerman, R H

2000-01-01

The author reviews the malaria research program in Sucre State, Venezuela, taking an ecosystem approach. The goal was to determine which methods could have been introduced at the onset that would have made the study more ecological and interdisciplinary. Neither an ecosystem approach nor integrated disease control were in place at the time of the study. This study began to introduce an ecosystem approach when two contrasting ecosystems in Sucre State were selected for study and vector control methods were implemented based on research results. The need to have a health policy in place with an eco-health approach is crucial to the success of research and control. The review suggests that sustainability is low when not all the stakeholders are involved in the design and implementation of the research and control strategy development. The lack of community involvement makes sustainability doubtful. The author concludes that there were two interdependent challenges for malaria control: development of an ecosystem approach for malaria research and control, and the implementation of an integrated disease control strategy, with malaria as one of the important health issues.

Enhancing students’ mathematical problem posing skill through writing in performance tasks strategy

NASA Astrophysics Data System (ADS)

Kadir; Adelina, R.; Fatma, M.

2018-01-01

Many researchers have studied the Writing in Performance Task (WiPT) strategy in learning, but only a few paid attention on its relation to the problem-posing skill in mathematics. The problem-posing skill in mathematics covers problem reformulation, reconstruction, and imitation. The purpose of the present study was to examine the effect of WiPT strategy on students’ mathematical problem-posing skill. The research was conducted at a Public Junior Secondary School in Tangerang Selatan. It used a quasi-experimental method with randomized control group post-test. The samples were 64 students consists of 32 students of the experiment group and 32 students of the control. A cluster random sampling technique was used for sampling. The research data were obtained by testing. The research shows that the problem-posing skill of students taught by WiPT strategy is higher than students taught by a conventional strategy. The research concludes that the WiPT strategy is more effective in enhancing the students’ mathematical problem-posing skill compared to the conventional strategy.

Drying based on temperature-detection-assisted control in microwave-assisted pulse-spouted vacuum drying.

PubMed

Cao, Xiaohuang; Zhang, Min; Qian, He; Mujumdar, Arun S

2017-06-01

An online temperature-detection-assisted control system of microwave-assisted pulse-spouted vacuum drying was newly developed. By using this system, temperature control can be automatically and continuously adjusted based on the detection of drying temperature and preset temperature. Various strategies for constant temperature control, linear temperature control and three-step temperature control were applied to drying carrot cubes. Drying kinetics and the quality of various temperature-controlled strategies online are evaluated for the new drying technology as well as its suitability as an alternative drying method. Drying time in 70 °C mode 1 had the shortest drying time and lowest energy consumption in all modes. A suitable colour, highest re-hydration ratio and fracture-hardness, and longest drying time occurred in 30-40-50 °C mode 3. The number of hot spots was reduced in 40-50-60 °C mode 3. Acceptable carrot snacks were obtained in 50-60-70 °C mode 3 and 70 °C mode 2. All temperature curves showed that the actual temperatures followed the preset temperatures appropriately. With this system, a linear temperature-controlled strategy and a three-step temperature-controlled strategy can improve product quality and heating non-uniformity compared to constant temperature control, but need greater energy consumption and longer drying time. A temperature-detection-assisted control system was developed for providing various drying strategies as a suitable alternative in making a snack product. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

The effects of rhythm control strategies versus rate control strategies for atrial fibrillation and atrial flutter: A systematic review with meta-analysis and Trial Sequential Analysis

PubMed Central

Gluud, Christian; Jakobsen, Janus C.

2017-01-01

Background Atrial fibrillation and atrial flutter may be managed by either a rhythm control strategy or a rate control strategy but the evidence on the clinical effects of these two intervention strategies is unclear. Our objective was to assess the beneficial and harmful effects of rhythm control strategies versus rate control strategies for atrial fibrillation and atrial flutter. Methods We searched CENTRAL, MEDLINE, Embase, LILACS, Web of Science, BIOSIS, Google Scholar, clinicaltrials.gov, TRIP, EU-CTR, Chi-CTR, and ICTRP for eligible trials comparing any rhythm control strategy with any rate control strategy in patients with atrial fibrillation or atrial flutter published before November 2016. Our primary outcomes were all-cause mortality, serious adverse events, and quality of life. Our secondary outcomes were stroke and ejection fraction. We performed both random-effects and fixed-effect meta-analysis and chose the most conservative result as our primary result. We used Trial Sequential Analysis (TSA) to control for random errors. Statistical heterogeneity was assessed by visual inspection of forest plots and by calculating inconsistency (I2) for traditional meta-analyses and diversity (D2) for TSA. Sensitivity analyses and subgroup analyses were conducted to explore the reasons for substantial statistical heterogeneity. We assessed the risk of publication bias in meta-analyses consisting of 10 trials or more with tests for funnel plot asymmetry. We used GRADE to assess the quality of the body of evidence. Results 25 randomized clinical trials (n = 9354 participants) were included, all of which were at high risk of bias. Meta-analysis showed that rhythm control strategies versus rate control strategies significantly increased the risk of a serious adverse event (risk ratio (RR), 1.10; 95% confidence interval (CI), 1.02 to 1.18; P = 0.02; I2 = 12% (95% CI 0.00 to 0.32); 21 trials), but TSA did not confirm this result (TSA-adjusted CI 0.99 to 1.22). The increased risk of a serious adverse event did not seem to be caused by any single component of the composite outcome. Meta-analysis showed that rhythm control strategies versus rate control strategies were associated with better SF-36 physical component score (mean difference (MD), 6.93 points; 95% CI, 2.25 to 11.61; P = 0.004; I2 = 95% (95% CI 0.94 to 0.96); 8 trials) and ejection fraction (MD, 4.20%; 95% CI, 0.54 to 7.87; P = 0.02; I2 = 79% (95% CI 0.69 to 0.85); 7 trials), but TSA did not confirm these results. Both meta-analysis and TSA showed no significant differences on all-cause mortality, SF-36 mental component score, Minnesota Living with Heart Failure Questionnaire, and stroke. Conclusions Rhythm control strategies compared with rate control strategies seem to significantly increase the risk of a serious adverse event in patients with atrial fibrillation. Based on current evidence, it seems that most patients with atrial fibrillation should be treated with a rate control strategy unless there are specific reasons (e.g., patients with unbearable symptoms due to atrial fibrillation or patients who are hemodynamically unstable due to atrial fibrillation) justifying a rhythm control strategy. More randomized trials at low risk of bias and low risk of random errors are needed. Trial registration PROSPERO CRD42016051433 PMID:29073191

Closed-Loop Control of Chemical Injection Rate for a Direct Nozzle Injection System

PubMed Central

Cai, Xiang; Walgenbach, Martin; Doerpmond, Malte; Schulze Lammers, Peter; Sun, Yurui

2016-01-01

To realize site-specific and variable-rate application of agricultural pesticides, accurately metering and controlling the chemical injection rate is necessary. This study presents a prototype of a direct nozzle injection system (DNIS) by which chemical concentration transport lag was greatly reduced. In this system, a rapid-reacting solenoid valve (RRV) was utilized for injecting chemicals, driven by a pulse-width modulation (PWM) signal at 100 Hz, so with varying pulse width the chemical injection rate could be adjusted. Meanwhile, a closed-loop control strategy, proportional-integral-derivative (PID) method, was applied for metering and stabilizing the chemical injection rate. In order to measure chemical flow rates and input them into the controller as a feedback in real-time, a thermodynamic flowmeter that was independent of chemical viscosity was used. Laboratory tests were conducted to assess the performance of DNIS and PID control strategy. Due to the nonlinear input–output characteristics of the RRV, a two-phase PID control process obtained better effects as compared with single PID control strategy. Test results also indicated that the set-point chemical flow rate could be achieved within less than 4 s, and the output stability was improved compared to the case without control strategy. PMID:26805833

40 CFR 52.126 - Control strategy and regulations: Particulate matter.

Code of Federal Regulations, 2010 CFR

2010-07-01

... be determined by using method 2 and traversing according to method 1. Gas analysis shall be performed using the integrated sample technique of method 3, and moisture content shall be determined by the condenser technique of method 4. (iii) All tests shall be conducted while the source is operating at the...

Adaptive Control for Buck Power Converter Using Fixed Point Inducting Control and Zero Average Dynamics Strategies

NASA Astrophysics Data System (ADS)

Hoyos Velasco, Fredy Edimer; García, Nicolás Toro; Garcés Gómez, Yeison Alberto

In this paper, the output voltage of a buck power converter is controlled by means of a quasi-sliding scheme. The Fixed Point Inducting Control (FPIC) technique is used for the control design, based on the Zero Average Dynamics (ZAD) strategy, including load estimation by means of the Least Mean Squares (LMS) method. The control scheme is tested in a Rapid Control Prototyping (RCP) system based on Digital Signal Processing (DSP) for dSPACE platform. The closed loop system shows adequate performance. The experimental and simulation results match. The main contribution of this paper is to introduce the load estimator by means of LMS, to make ZAD and FPIC control feasible in load variation conditions. In addition, comparison results for controlled buck converter with SMC, PID and ZAD-FPIC control techniques are shown.

Postural strategies assessed with inertial sensors in healthy and parkinsonian subjects.

PubMed

Baston, Chiara; Mancini, Martina; Schoneburg, Bernadette; Horak, Fay; Rocchi, Laura

2014-01-01

The present study introduces a novel instrumented method to characterize postural movement strategies to maintain balance during stance (ankle and hip strategy), by means of inertial sensors, positioned on the legs and on the trunk. We evaluated postural strategies in subjects with 2 types of Parkinsonism: idiopathic Parkinson's disease (PD) and Progressive Supranuclear Palsy (PSP), and in age-matched control subjects standing under perturbed conditions implemented by the Sensory Organization Test (SOT). Coordination between the upper and lower segments of the body during postural sway was measured using a covariance index over time, by a sliding-window algorithm. Afterwards, a postural strategy index was computed. We also measured the amount of postural sway, as adjunctive information to characterize balance, by the root mean square of the horizontal trunk acceleration signal (RMS). showed that control subjects were able to change their postural strategy, whilst PSP and PD subjects persisted in use of an ankle strategy in all conditions. PD subjects had RMS values similar to control subjects even without changing postural strategy appropriately, whereas PSP subjects showed much larger RMS values than controls, resulting in several falls during the most challenging SOT conditions (5 and 6). Results are in accordance with the corresponding clinical literature describing postural behavior in the same kind of subjects. The proposed strategy index, based on the use of inertial sensors on the upper and lower body segments, is a promising and unobtrusive tool to characterize postural strategies performed to attain balance. Copyright © 2014 Elsevier B.V. All rights reserved.

A quantum dynamics study of the benzopyran ring opening guided by laser pulses

NASA Astrophysics Data System (ADS)

Saab, Mohamad; Doriol, Loïc Joubert; Lasorne, Benjamin; Guérin, Stéphane; Gatti, Fabien

2014-10-01

The ring-opening photoisomerization of benzopyran, which occurs via a photochemical route involving a conical intersection, has been studied with quantum dynamics calculations using the multi-configuration time-dependent Hartree method (MCTDH). We introduce a mechanistic strategy to control the conversion of benzopyran to merocyanine with laser pulses. We use a six-dimensional model developed in a previous work for the potential energy surfaces (PES) based on an extension of the vibronic-coupling Hamiltonian model (diabatization method by ansatz), which depends on the most active degrees of freedom. The main objective of these quantum dynamics simulations is to provide a set of strategies that could help experimentalists to control the photoreactivity vs. photostability ratio (selectivity). In this work we present: (i) a pump-dump technique used to control the photostability, (ii) a two-step strategy to enhance the reactivity of the system: first, a pure vibrational excitation in the electronic ground state that prepares the system and, second, an ultraviolet excitation that brings the system to the first adiabatic electronic state; (iii) finally the effect of a non-resonant pulse (Stark effect) on the dynamics.

Randomized Controlled Trial Comparing Tailoring Methods of Multimedia-Based Fall Prevention Education for Community-Dwelling Older Adults

PubMed Central

Schepens, Stacey L.; Panzer, Victoria; Goldberg, Allon

2012-01-01

OBJECTIVE We attempted to determine whether multimedia fall prevention education using different instructional strategies increases older adults’ knowledge of fall threats and their fall prevention behaviors. METHOD Fifty-three community-dwelling older adults were randomized to two educational groups or a control group. Multimedia-based educational interventions to increase fall threats knowledge and encourage fall prevention behaviors had two tailoring strategies: (1) improve content realism for individual learners (authenticity group) and (2) highlight program goals and benefits while using participants’ content selections (motivation group). Knowledge was measured at baseline and 1-mo follow-up. Participants recorded prevention behaviors for 1 mo. RESULTS Intervention group participants showed greater knowledge gains and posttest knowledge than did control group participants. The motivation group engaged in more prevention behaviors over 1 mo than did the other groups. CONCLUSION Tailoring fall prevention education by addressing authenticity and motivation successfully improved fall threats knowledge. Combining motivational strategies with multimedia education increased the effectiveness of the intervention in encouraging fall prevention behaviors. PMID:22214115

Direct torque control method applied to the WECS based on the PMSG and controlled with backstepping approach

NASA Astrophysics Data System (ADS)

Errami, Youssef; Obbadi, Abdellatif; Sahnoun, Smail; Ouassaid, Mohammed; Maaroufi, Mohamed

2018-05-01

This paper proposes a Direct Torque Control (DTC) method for Wind Power System (WPS) based Permanent Magnet Synchronous Generator (PMSG) and Backstepping approach. In this work, generator side and grid-side converter with filter are used as the interface between the wind turbine and grid. Backstepping approach demonstrates great performance in complicated nonlinear systems control such as WPS. So, the control method combines the DTC to achieve Maximum Power Point Tracking (MPPT) and Backstepping approach to sustain the DC-bus voltage and to regulate the grid-side power factor. In addition, control strategy is developed in the sense of Lyapunov stability theorem for the WPS. Simulation results using MATLAB/Simulink validate the effectiveness of the proposed controllers.

Photochemical internalisation, a minimally invasive strategy for light-controlled endosomal escape of cancer stem cell-targeting therapeutics.

PubMed

Selbo, Pål Kristian; Bostad, Monica; Olsen, Cathrine Elisabeth; Edwards, Victoria Tudor; Høgset, Anders; Weyergang, Anette; Berg, Kristian

2015-08-01

Despite progress in radio-, chemo- and photodynamic-therapy (PDT) of cancer, treatment resistance still remains a major problem for patients with aggressive tumours. Cancer stem cells (CSCs) or tumour-initiating cells are intrinsically and notoriously resistant to conventional cancer therapies and are proposed to be responsible for the recurrence of tumours after therapy. According to the CSC hypothesis, it is imperative to develop novel anticancer agents or therapeutic strategies that take into account the biology and role of CSCs. The present review outlines our recent study on photochemical internalisation (PCI) using the clinically relevant photosensitiser TPCS2a/Amphinex® as a rational, non-invasive strategy for the light-controlled endosomal escape of CSC-targeting drugs. PCI is an intracellular drug delivery method based on light-induced ROS-generation and a subsequent membrane-disruption of endocytic vesicles, leading to cytosolic release of the entrapped drugs of interest. In different proof-of-concept studies we have demonstrated that PCI of CSC-directed immunotoxins targeting CD133, CD44, CSPG4 and EpCAM is a highly specific and effective strategy for killing cancer cells and CSCs. CSCs overexpressing CD133 are PDT-resistant; however, this is circumvented by PCI of CD133-targeting immunotoxins. In view of the fact that TPCS2a is not a substrate of the efflux pumps ABCG2 and P-glycoprotein (ABCB1), the PCI-method is a promising anti-CSC therapeutic strategy. Due to a laser-controlled exposure, PCI of CSC-targeting drugs will be confined exclusively to the tumour tissue, suggesting that this drug delivery method has the potential to spare distant normal stem cells.

Strategies for global optimization in photonics design.

PubMed

Vukovic, Ana; Sewell, Phillip; Benson, Trevor M

2010-10-01

This paper reports on two important issues that arise in the context of the global optimization of photonic components where large problem spaces must be investigated. The first is the implementation of a fast simulation method and associated matrix solver for assessing particular designs and the second, the strategies that a designer can adopt to control the size of the problem design space to reduce runtimes without compromising the convergence of the global optimization tool. For this study an analytical simulation method based on Mie scattering and a fast matrix solver exploiting the fast multipole method are combined with genetic algorithms (GAs). The impact of the approximations of the simulation method on the accuracy and runtime of individual design assessments and the consequent effects on the GA are also examined. An investigation of optimization strategies for controlling the design space size is conducted on two illustrative examples, namely, 60° and 90° waveguide bends based on photonic microstructures, and their effectiveness is analyzed in terms of a GA's ability to converge to the best solution within an acceptable timeframe. Finally, the paper describes some particular optimized solutions found in the course of this work.

A novel disturbance-observer based friction compensation scheme for ball and plate system.

PubMed

Wang, Yongkun; Sun, Mingwei; Wang, Zenghui; Liu, Zhongxin; Chen, Zengqiang

2014-03-01

Friction is often ignored when designing a controller for the ball and plate system, which can lead to steady-error and stick-slip phenomena, especially for the small amplitude command. It is difficult to achieve high-precision control performance for the ball and plate system because of its friction. A novel reference compensation strategy is presented to attenuate the aftereffects caused by the friction. To realize this strategy, a linear control law is proposed based on a reduced-order observer. Neither the accurate friction model nor the estimation of specific characteristic parameters is needed in this design. Moreover, the describing function method illustrates that the limit cycle can be avoided. Finally, the comparative mathematical simulations and the practical experiments are used to validate the effectiveness of the proposed method. © 2013 ISA Published by ISA All rights reserved.

A nonlinear control method based on ANFIS and multiple models for a class of SISO nonlinear systems and its application.

PubMed

Zhang, Yajun; Chai, Tianyou; Wang, Hong

2011-11-01

This paper presents a novel nonlinear control strategy for a class of uncertain single-input and single-output discrete-time nonlinear systems with unstable zero-dynamics. The proposed method combines adaptive-network-based fuzzy inference system (ANFIS) with multiple models, where a linear robust controller, an ANFIS-based nonlinear controller and a switching mechanism are integrated using multiple models technique. It has been shown that the linear controller can ensure the boundedness of the input and output signals and the nonlinear controller can improve the dynamic performance of the closed loop system. Moreover, it has also been shown that the use of the switching mechanism can simultaneously guarantee the closed loop stability and improve its performance. As a result, the controller has the following three outstanding features compared with existing control strategies. First, this method relaxes the assumption of commonly-used uniform boundedness on the unmodeled dynamics and thus enhances its applicability. Second, since ANFIS is used to estimate and compensate the effect caused by the unmodeled dynamics, the convergence rate of neural network learning has been increased. Third, a "one-to-one mapping" technique is adapted to guarantee the universal approximation property of ANFIS. The proposed controller is applied to a numerical example and a pulverizing process of an alumina sintering system, respectively, where its effectiveness has been justified.

Analysis of Q fever in Dutch dairy goat herds and assessment of control measures by means of a transmission model.

PubMed

Bontje, D M; Backer, J A; Hogerwerf, L; Roest, H I J; van Roermund, H J W

2016-01-01

Between 2006 and 2009 the largest human Q fever epidemic ever described occurred in the Netherlands. The source of infection was traced back to dairy goat herds with abortion problems due to Q fever. The first aim of control measures taken in these herds was the reduction of human exposure. To analyze Q fever dynamics in goat herds and to study the effect of control measures, a within-herd model of Coxiella burnetii transmission in dairy goat herds was developed. With this individual-based stochastic model we evaluated six control strategies and three herd management styles and studied which strategy leads to a lower Q fever prevalence and/or to disease extinction in a goat herd. Parameter values were based on literature and on experimental work. The model could not be validated with independent data. The results of the epidemiological model were: (1) Vaccination is effective in quickly reducing the prevalence in a dairy goat herd. (2) When taking into account the average time to extinction of the infection and the infection pressure in a goat herd, the most effective control strategy is preventive yearly vaccination, followed by the reactive strategies to vaccinate after an abortion storm or after testing BTM (bulk tank milk) positive. (3) As C. burnetii in dried dust may affect public health, an alternative ranking method is based on the cumulative amount of C. burnetii emitted into the environment (from disease introduction until extinction). Using this criterion, the same control strategies are effective as when based on time to extinction and infection pressure (see 2). (4) As the bulk of pathogen excretion occurs during partus and abortion, culling of pregnant animals during an abortion storm leads to a fast reduction of the amount of C. burnetii emitted into the environment. However, emission is not entirely prevented and Q fever will not be eradicated in the herd by this measure. (5) A search & destroy (i.e. test and cull) method by PCR of individual milk samples with a detection probability of 50% of detecting and culling infected goats - that excrete C. burnetii intermittently - will not result in eradication of Q fever in the herd. This control strategy was the least effective of the six evaluated strategies. Subject to model limitations, our results indicate that only vaccination is capable of preventing and controlling Q fever outbreaks in dairy goat farms. Thus, preventive vaccination should be considered as an ongoing control measure. Copyright © 2015 Elsevier B.V. All rights reserved.

The use of modelling to evaluate and adapt strategies for animal disease control.

PubMed

Saegerman, C; Porter, S R; Humblet, M F

2011-08-01

Disease is often associated with debilitating clinical signs, disorders or production losses in animals and/or humans, leading to severe socio-economic repercussions. This explains the high priority that national health authorities and international organisations give to selecting control strategies for and the eradication of specific diseases. When a control strategy is selected and implemented, an effective method of evaluating its efficacy is through modelling. To illustrate the usefulness of models in evaluating control strategies, the authors describe several examples in detail, including three examples of classification and regression tree modelling to evaluate and improve the early detection of disease: West Nile fever in equids, bovine spongiform encephalopathy (BSE) and multifactorial diseases, such as colony collapse disorder (CCD) in the United States. Also examined are regression modelling to evaluate skin test practices and the efficacy of an awareness campaign for bovine tuberculosis (bTB); mechanistic modelling to monitor the progress of a control strategy for BSE; and statistical nationwide modelling to analyse the spatio-temporal dynamics of bTB and search for potential risk factors that could be used to target surveillance measures more effectively. In the accurate application of models, an interdisciplinary rather than a multidisciplinary approach is required, with the fewest assumptions possible.

Helicopter Control Energy Reduction Using Moving Horizontal Tail

PubMed Central

Oktay, Tugrul; Sal, Firat

2015-01-01

Helicopter moving horizontal tail (i.e., MHT) strategy is applied in order to save helicopter flight control system (i.e., FCS) energy. For this intention complex, physics-based, control-oriented nonlinear helicopter models are used. Equations of MHT are integrated into these models and they are together linearized around straight level flight condition. A specific variance constrained control strategy, namely, output variance constrained Control (i.e., OVC) is utilized for helicopter FCS. Control energy savings due to this MHT idea with respect to a conventional helicopter are calculated. Parameters of helicopter FCS and dimensions of MHT are simultaneously optimized using a stochastic optimization method, namely, simultaneous perturbation stochastic approximation (i.e., SPSA). In order to observe improvement in behaviors of classical controls closed loop analyses are done. PMID:26180841

Communications strategies for on-ship CDPC systems.

PubMed

Jerome, Carlos

2012-01-01

Individual countries and international organisations have worked on standardising methods for on-ship prevention and control of communicable disease (CDPC). A number of voices have called for integrating the various aspects of maritime CDPC. The purpose of this article is to further conceptualise the totality of on-ship CDPC activity as an integrated system and to suggest a few strategies for communications in such systems. The methods used to summarise standardisation and integration of ship-board CDPC procedures included a scientific literature review and a web search. The fields of the review were maritime, health, and technology sources. Special attention was paid to material dealing with communications methods and issues related to ship-board systems and methods to manage communicable diseases. Effective communications strategies are vital for the success of CDPC systems. I suggest some specific viewpoints and strategies to improve communications: (i) It is sometimes helpful to view the Constituent Relations Management (CRM) team as a system component. This view highlights the fact that an on-ship CDPC system will be well designed and maintained only if constituent relations are well designed and maintained. (ii) For rapid communications with appropriate groups of constituents, it is important to structure groups of constituents, with the ability to rapidly apply set-theoretic operations to those groups. (iii) Optimistic concurrency control is generally the appropriate general strategy for synchronisation of on-ship CDPC data locations and data storage types. This may be modified in special situations, in particular with a latest-update-wins policy for disease contraction data in an epidemic. (iv) To encourage traveller cooperation with CDPC efforts, cultural activities may be helpful.

Implementation strategies for guidelines at ICUs: a systematic review.

PubMed

Jordan, Portia; Mpasa, Ferestas; Ten Ham-Baloyi, Wilma; Bowers, Candice

2017-05-08

Purpose The purpose of this paper is to critically analyze empirical studies related to the implementation strategies for clinical practice guidelines (CPGs) in intensive care units (ICUs). Design/methodology/approach A systematic review with a narrative synthesis adapted from Popay et al.'s method for a narrative synthesis was conducted. A search using CINAHL, Google Scholar, Academic search complete, Cochrane Register for Randomized Controlled Trials, MEDLINE via PUBMED and grey literature was conducted in 2014 and updated in 2016 (August). After reading the abstracts, titles and full-text articles, 11 ( n=11) research studies met the inclusion criteria. Findings After critical appraisal, using the Joanna Briggs Critical Appraisal Tools, eight randomized controlled trials conducted in adult and neonatal ICUs using implementation strategies remained. Popay et al.'s method for narrative synthesis was adapted and used to analyze and synthesize the data and formulate concluding statements. Included studies found that multi-faceted strategies appear to be more effective than single strategies. Strategies mostly used were printed educational materials, information/ sessions, audit, feedback, use of champion leaders, educational outreach visits, and computer or internet usage. Practical training, monitoring visits and grand rounds were less used. Practical implications Findings can be used by clinicians to implement the best combination of multi-faceted implementation strategies in the ICUs in order to enhance the optimal use of CPGs. Originality/value No systematic review was previously done on the implementation strategies that should be used best for optimal CPG implementation in the ICU.

Gene Delivery Strategies to Promote Spinal Cord Repair

PubMed Central

Walthers, Christopher M; Seidlits, Stephanie K

2015-01-01

Gene therapies hold great promise for the treatment of many neurodegenerative disorders and traumatic injuries in the central nervous system. However, development of effective methods to deliver such therapies in a controlled manner to the spinal cord is a necessity for their translation to the clinic. Although essential progress has been made to improve efficiency of transgene delivery and reduce the immunogenicity of genetic vectors, there is still much work to be done to achieve clinical strategies capable of reversing neurodegeneration and mediating tissue regeneration. In particular, strategies to achieve localized, robust expression of therapeutic transgenes by target cell types, at controlled levels over defined time periods, will be necessary to fully regenerate functional spinal cord tissues. This review summarizes the progress over the last decade toward the development of effective gene therapies in the spinal cord, including identification of appropriate target genes, improvements to design of genetic vectors, advances in delivery methods, and strategies for delivery of multiple transgenes with synergistic actions. The potential of biomaterials to mediate gene delivery while simultaneously providing inductive scaffolding to facilitate tissue regeneration is also discussed. PMID:25922572

Multidimensional optimal droop control for wind resources in DC microgrids

NASA Astrophysics Data System (ADS)

Bunker, Kaitlyn J.

Two important and upcoming technologies, microgrids and electricity generation from wind resources, are increasingly being combined. Various control strategies can be implemented, and droop control provides a simple option without requiring communication between microgrid components. Eliminating the single source of potential failure around the communication system is especially important in remote, islanded microgrids, which are considered in this work. However, traditional droop control does not allow the microgrid to utilize much of the power available from the wind. This dissertation presents a novel droop control strategy, which implements a droop surface in higher dimension than the traditional strategy. The droop control relationship then depends on two variables: the dc microgrid bus voltage, and the wind speed at the current time. An approach for optimizing this droop control surface in order to meet a given objective, for example utilizing all of the power available from a wind resource, is proposed and demonstrated. Various cases are used to test the proposed optimal high dimension droop control method, and demonstrate its function. First, the use of linear multidimensional droop control without optimization is demonstrated through simulation. Next, an optimal high dimension droop control surface is implemented with a simple dc microgrid containing two sources and one load. Various cases for changing load and wind speed are investigated using simulation and hardware-in-the-loop techniques. Optimal multidimensional droop control is demonstrated with a wind resource in a full dc microgrid example, containing an energy storage device as well as multiple sources and loads. Finally, the optimal high dimension droop control method is applied with a solar resource, and using a load model developed for a military patrol base application. The operation of the proposed control is again investigated using simulation and hardware-in-the-loop techniques.

Interface-Assisted Synthesis of 2D Materials: Trend and Challenges.

PubMed

Dong, Renhao; Zhang, Tao; Feng, Xinliang

2018-06-18

The discovery of graphene one decade ago has triggered enormous interest in developing two-dimensional materials (2DMs)-that is 2D allotropes of various elements or compounds (consisting of two or more covalently bonded elements) or molecular frameworks with periodic structures. At present, various synthesis strategies have been exploited to produce 2DMs, such as top-down exfoliation and bottom-up chemical vapor deposition and solution synthesis methods. In this review article, we will highlight the interfacial roles toward the controlled synthesis of inorganic and organic 2DMs with varied structural features. We will summarize the state-of-the-art progress on interfacial synthesis strategies and address their advancements in the structural, morphological, and crystalline control by the direction of the arrangement of the molecules or precursors at a confined 2D space. First, we will provide an overview of the interfaces and introduce their advantages and uniqueness for the synthesis of 2DMs, followed by a brief classification of inorganic and organic 2DMs achieved by interfacial synthesis. Next, the currently developed interfacial synthesis strategies combined with representative inorganic and organic 2DMs are summarized, including the description of method details, the corresponding structural features, and the insights into the advantages and limitations of the synthesis methods, along with some recommendable characterization methods for understanding the interfacial assembly of the precursors and crystal growth of 2DMs. After that, we will discuss several classes of emerging organic 2DMs with particular emphasis on the structural control by the interfacial synthesis strategies. Note that, inorganic 2DMs will not be categorized separately due to the fact that a number of review articles have covered the synthesis, structure, processing, and applications. Finally, the challenges and perspectives are provided regarding the future development of interface-assisted synthesis of 2DMs with diverse structural and functional control.

Candidate proof mass actuator control laws for the vibration suppression of a frame

NASA Technical Reports Server (NTRS)

Umland, Jeffrey W.; Inman, Daniel J.

1991-01-01

The vibration of an experimental flexible space truss is controlled with internal control forces produced by several proof mass actuators. Four candidate control law strategies are evaluated in terms of performance and robustness. These control laws are experimentally implemented on a quasi free-free planar truss. Sensor and actuator dynamics are included in the model such that the final closed loop is self-equilibrated. The first two control laws considered are based on direct output feedback and consist of tuning the actuator feedback gains to the lowest mode intended to receive damping. The first method feeds back only the position and velocity of the proof mass relative to the structure; this results in a traditional vibration absorber. The second method includes the same feedback paths as the first plus feedback of the local structural velocity. The third law is designed with robust H infinity control theory. The fourth strategy is an active implementation of a viscous damper, where the actuator is configured to provide a bending moment at two points on the structure. The vibration control system is then evaluated in terms of how it would benefit the space structure's position control system.

Quality of life, coping strategies, social support and self-efficacy in women after acute myocardial infarction: a mixed methods approach.

PubMed

Fuochi, G; Foà, C

2018-03-01

Quality of life, coping strategies, social support and self-efficacy are important psychosocial variables strongly affecting the experience of acute myocardial infarction (AMI) in women. To gain a more in-depth understanding of how coping strategies, self-efficacy, quality of life and social support shape women's adjustment to AMI. Mixed methods study. Quantitative data were collected through a standardised questionnaire on coping strategies, self-efficacy, quality of life and social support. Qualitative data stemmed from 57 semistructured interviews conducted with post-AMI female patients on related topics. Quantitative data were analysed with unpaired two-sample t-tests on the means, comparing women who experienced AMI (N = 77) with a control group of women who did not have AMI (N = 173), and pairwise correlations on the AMI sample. Qualitative data were grouped into coding families and analysed through thematic content analysis. Qualitative and quantitative results were then integrated, for different age groups. Quantitative results indicated statistically significant differences between women who experienced AMI and the control group: the former showed lower self-perceived health, perceived social support and social support coping, but greater self-efficacy, use of acceptance, avoidance and religious coping. Pairwise correlations showed that avoidance coping strategy was negatively correlated with quality of life, while the opposite was true for problem-oriented coping, perceived social support and self-efficacy. Qualitative results extended and confirmed quantitative results, except for coping strategies: avoidance coping seemed more present than reported in the standardised measures. Mixed methods provide understanding of the importance of social support, self-efficacy and less avoidant coping strategies to women's adjustment to AMI. Women need support from health professionals with knowledge of these topics, to facilitate their adaptation to AMI. © 2017 Nordic College of Caring Science.

Strategies of performance self-monitoring in automotive production.

PubMed

Faye, Hélène; Falzon, Pierre

2009-09-01

Production in the automotive industry, based on assembly line work, is now characterized by lean manufacturing and customization. This results in greater flexibility and increased quality demands, including worker performance self-monitoring. The objectives of this study are to refine the concept of performance self-monitoring and to characterize the strategies developed by operators to achieve it. Data were collected based on the method of individual auto-confrontation, consisting of two steps: eleven assembly-line operators of a French automotive company were individually observed and video-taped while they were working; an interview then allowed each operator to discuss his/her activity based on the video-tape. This study expands the concept of performance self-monitoring by highlighting three types of strategies directly oriented toward quality: prevention, feedback control and control action strategies.

Canine-Based Strategies for Prevention and Control of Visceral Leishmaniasis in Brazil

PubMed Central

Ovallos, Fredy G.; Amaku, Marcus; Carrillo, Eugenia; Moreno, Javier; Galati, Eunice A. B.; Lopes, Estela G.; Soares, Rodrigo M.; Ferreira, Fernando

2016-01-01

Visceral leishmaniasis (VL) is a zoonosis found worldwide. Its incidence has increased in Brazil in recent years, representing a serious public and animal health problem. The strategies applied in Brazil are questionable and are not sufficient to control the disease. Thus, we have compared the efficacy of some of the currently available strategies focused on dogs to prevent and control zoonotic VL in endemic areas by optimizing a mathematical model. The simulations showed that the elimination of seropositive dogs, the use of insecticide-impregnated dog collars, and the vaccination of dogs significantly contribute to reducing the prevalence of infection in both canines and humans. The use of insecticide-impregnated collars presented the highest level of efficacy mainly because it directly affected the force of infection and vector-dog contact. In addition, when used at a coverage rate of 90%, insecticide-impregnated collar was able to decrease the prevalence of seropositive dogs and humans to zero; moreover, because of the easy application and acceptance by the targeted population, these collars may be considered the most feasible for inclusion in public policies among the three simulated measures. Vaccination and euthanasia were efficacious, but the latter method is strongly criticized on ethical grounds, and both methods present difficulties for inclusion in public policies. When we compared the use of euthanasia and vaccination at coverages of 70 and 90%, respectively, the proportion of infected populations were similar. However, on evaluating the implications of both of these methods, particularly the negative aspects of culling dogs and the proportion of animals protected by vaccination, the latter measure appears to be the better option if the total cost is not significantly higher. The comparison of complications and advantages of different control strategies allows us to analyze the optimal measure and offer strategies to veterinary and public health authorities for making decisions to prevent and control zoonotic VL. Hence, improvements in both public and animal health can be achieved in regions with scenarios similar to that considered in the present study; such scenarios are characteristically found in some areas of Brazil and other countries. PMID:27471852

Breeding for resistance to gastrointestinal nematodes - the potential in low-input/output small ruminant production systems.

PubMed

Zvinorova, P I; Halimani, T E; Muchadeyi, F C; Matika, O; Riggio, V; Dzama, K

2016-07-30

The control of gastrointestinal nematodes (GIN) is mainly based on the use of drugs, grazing management, use of copper oxide wire particles and bioactive forages. Resistance to anthelmintic drugs in small ruminants is documented worldwide. Host genetic resistance to parasites, has been increasingly used as a complementary control strategy, along with the conventional intervention methods mentioned above. Genetic diversity in resistance to GIN has been well studied in experimental and commercial flocks in temperate climates and more developed economies. However, there are very few report outputs from the more extensive low-input/output smallholder systems in developing and emerging countries. Furthermore, results on quantitative trait loci (QTL) associated with nematode resistance from various studies have not always been consistent, mainly due to the different nematodes studied, different host breeds, ages, climates, natural infections versus artificial challenges, infection level at sampling periods, among others. The increasing use of genetic markers (Single Nucleotide Polymorphisms, SNPs) in GWAS or the use of whole genome sequence data and a plethora of analytic methods offer the potential to identify loci or regions associated nematode resistance. Genomic selection as a genome-wide level method overcomes the need to identify candidate genes. Benefits in genomic selection are now being realised in dairy cattle and sheep under commercial settings in the more advanced countries. However, despite the commercial benefits of using these tools, there are practical problems associated with incorporating the use of marker-assisted selection or genomic selection in low-input/output smallholder farming systems breeding schemes. Unlike anthelmintic resistance, there is no empirical evidence suggesting that nematodes will evolve rapidly in response to resistant hosts. The strategy of nematode control has evolved to a more practical manipulation of host-parasite equilibrium in grazing systems by implementation of various strategies, in which improvement of genetic resistance of small ruminant should be included. Therefore, selection for resistant hosts can be considered as one of the sustainable control strategy, although it will be most effective when used to complement other control strategies such as grazing management and improving efficiency of anthelmintics currently. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Canine-Based Strategies for Prevention and Control of Visceral Leishmaniasis in Brazil.

PubMed

Sevá, Anaiá P; Ovallos, Fredy G; Amaku, Marcus; Carrillo, Eugenia; Moreno, Javier; Galati, Eunice A B; Lopes, Estela G; Soares, Rodrigo M; Ferreira, Fernando

2016-01-01

Visceral leishmaniasis (VL) is a zoonosis found worldwide. Its incidence has increased in Brazil in recent years, representing a serious public and animal health problem. The strategies applied in Brazil are questionable and are not sufficient to control the disease. Thus, we have compared the efficacy of some of the currently available strategies focused on dogs to prevent and control zoonotic VL in endemic areas by optimizing a mathematical model. The simulations showed that the elimination of seropositive dogs, the use of insecticide-impregnated dog collars, and the vaccination of dogs significantly contribute to reducing the prevalence of infection in both canines and humans. The use of insecticide-impregnated collars presented the highest level of efficacy mainly because it directly affected the force of infection and vector-dog contact. In addition, when used at a coverage rate of 90%, insecticide-impregnated collar was able to decrease the prevalence of seropositive dogs and humans to zero; moreover, because of the easy application and acceptance by the targeted population, these collars may be considered the most feasible for inclusion in public policies among the three simulated measures. Vaccination and euthanasia were efficacious, but the latter method is strongly criticized on ethical grounds, and both methods present difficulties for inclusion in public policies. When we compared the use of euthanasia and vaccination at coverages of 70 and 90%, respectively, the proportion of infected populations were similar. However, on evaluating the implications of both of these methods, particularly the negative aspects of culling dogs and the proportion of animals protected by vaccination, the latter measure appears to be the better option if the total cost is not significantly higher. The comparison of complications and advantages of different control strategies allows us to analyze the optimal measure and offer strategies to veterinary and public health authorities for making decisions to prevent and control zoonotic VL. Hence, improvements in both public and animal health can be achieved in regions with scenarios similar to that considered in the present study; such scenarios are characteristically found in some areas of Brazil and other countries.

The Research on Integrated Strategy of Supply Chain Information Systems in the Automobile Industry Based on Order-To-Delivery Mode

NASA Astrophysics Data System (ADS)

Li, Ming; Gan, Lianzhen; He, Xuefeng

The automotive industry there are different degrees of impairment of many companies supply chain IT strategy. In this paper, in which the automotive industry supply chain management business cooperation between enterprises loose, poor exchange of information leading to the presence or delays in product customization, supply of raw materials, material control, production planning and control, sales and service and a fast response propose a series of typical problems of scientific and rational supply chain information integration strategy. The strategy through the development system integration platform, improve internal ERP system, implementation of supply chain management and other methods. Put some protection principles in the information process, to ensure the correct implementation of supply chain IT strategy, and ultimately achieve collaborative business development concept and enhance the automotive industry as a whole level of information.

A Review of Transformer Aging and Control Strategies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gourisetti, Sri Nikhil Gup; Kirkham, Harold; Sivaraman, Deepak

Transformer aging is an important challenge in power system. Distribution transformers themselves are minimally controllable, but smart meters provide excellent, new insights into electrical loads, which insights can be used to understand and mitigate transformer aging. The nature of transformer loads is changing with the integration of distributed energy resources (DERs) and electric vehicles (EVs). This paper first reviews factors that influence the aging of distribution transformers, including root causes of transformer failure. Existing and proposed load control methods are then discussed. A distribution model is introduced to help evaluate potential control methods.

Guidelines for Controlling Indoor Air Quality Problems Associated with Kilns, Copiers, and Welding in Schools. Technical Bulletin.

ERIC Educational Resources Information Center

Turner, Ronald W.; And Others

Guidelines for controlling indoor air quality problems associated with kilns, copiers, and welding in schools are provided in this document. Individual sections on kilns, duplicating equipment, and welding operations contain information on the following: sources of contaminants; health effects; methods of control; ventilation strategies; and…

Chemical control of ticks on cattle and the resistance of these parasites to acaricides.

PubMed

George, J E; Pound, J M; Davey, R B

2004-01-01

Toward the end of the nineteenth century a complex of problems related to ticks and tick-borne diseases of cattle created a demand for methods to control ticks and reduce losses of cattle. The discovery and use of arsenical solutions in dipping vats for treating cattle to protect them against ticks revolutionized tick and tick-borne disease control programmes. Arsenic dips for cattle were used for about 40 years before the evolution of resistance of ticks to the chemical, and the development and marketing of synthetic organic acaricides after World War II provided superior alternative products. Most of the major groups of organic pesticides are represented on the list of chemicals used to control ticks on cattle. Unfortunately, the successive evolution of resistance of ticks to acaricides in each chemical group with the concomitant reduction in the usefulness of a group of acaricides is a major reason for the diversity of acaricides. Whether a producer chooses a traditional method for treating cattle with an acaricide or uses a new method, he must recognize the benefits, limitations and potential problems with each application method and product. Simulation models and research were the basis of recommendations for tick control strategies advocating approaches that reduced reliance on acaricides. These recommendations for controlling ticks on cattle are in harmony with recommendations for reducing the rate of selection for acaricide resistance. There is a need to transfer knowledge about tick control and resistance mitigation strategies to cattle producers.

Reliability of unstable periodic orbit based control strategies in biological systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mishra, Nagender; Singh, Harinder P.; Hasse, Maria

2015-04-15

Presence of recurrent and statistically significant unstable periodic orbits (UPOs) in time series obtained from biological systems is now routinely used as evidence for low dimensional chaos. Extracting accurate dynamical information from the detected UPO trajectories is vital for successful control strategies that either aim to stabilize the system near the fixed point or steer the system away from the periodic orbits. A hybrid UPO detection method from return maps that combines topological recurrence criterion, matrix fit algorithm, and stringent criterion for fixed point location gives accurate and statistically significant UPOs even in the presence of significant noise. Geometry ofmore » the return map, frequency of UPOs visiting the same trajectory, length of the data set, strength of the noise, and degree of nonstationarity affect the efficacy of the proposed method. Results suggest that establishing determinism from unambiguous UPO detection is often possible in short data sets with significant noise, but derived dynamical properties are rarely accurate and adequate for controlling the dynamics around these UPOs. A repeat chaos control experiment on epileptic hippocampal slices through more stringent control strategy and adaptive UPO tracking is reinterpreted in this context through simulation of similar control experiments on an analogous but stochastic computer model of epileptic brain slices. Reproduction of equivalent results suggests that far more stringent criteria are needed for linking apparent success of control in such experiments with possible determinism in the underlying dynamics.« less

EXPERIMENTAL AND THEORETICAL EVALUATIONS OF OBSERVATIONAL-BASED TECHNIQUES

EPA Science Inventory

Observational Based Methods (OBMs) can be used by EPA and the States to develop reliable ozone controls approaches. OBMs use actual measured concentrations of ozone, its precursors, and other indicators to determine the most appropriate strategy for ozone control. The usual app...

CHOOSING THE OPTIMUM FINANCIAL STRATEGY FOR POLLUTION CONTROL INVESTMENTS

EPA Science Inventory

This publication was designed to alert industry to qualifications for and availability of financial assistance from federal, state and local governments, and will illustrate that it is well worth the time to analyze the special methods of financing pollution control expenditures ...

Decentralized Interleaving of Paralleled Dc-Dc Buck Converters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Brian B; Rodriguez, Miguel; Sinha, Mohit

We present a decentralized control strategy that yields switch interleaving among parallel-connected dc-dc buck converters. The proposed method is based on the digital implementation of the dynamics of a nonlinear oscillator circuit as the controller. Each controller is fully decentralized, i.e., it only requires the locally measured output current to synthesize the pulse width modulation (PWM) carrier waveform and no communication between different controllers is needed. By virtue of the intrinsic electrical coupling between converters, the nonlinear oscillator-based controllers converge to an interleaved state with uniform phase-spacing across PWM carriers. To the knowledge of the authors, this work presents themore » first fully decentralized strategy for switch interleaving in paralleled dc-dc buck converters.« less

Decentralized Interleaving of Paralleled Dc-Dc Buck Converters: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Brian B; Rodriguez, Miguel; Sinha, Mohit

We present a decentralized control strategy that yields switch interleaving among parallel connected dc-dc buck converters without communication. The proposed method is based on the digital implementation of the dynamics of a nonlinear oscillator circuit as the controller. Each controller is fully decentralized, i.e., it only requires the locally measured output current to synthesize the pulse width modulation (PWM) carrier waveform. By virtue of the intrinsic electrical coupling between converters, the nonlinear oscillator-based controllers converge to an interleaved state with uniform phase-spacing across PWM carriers. To the knowledge of the authors, this work represents the first fully decentralized strategy formore » switch interleaving of paralleled dc-dc buck converters.« less

Design and Development of a High Speed Sorting System Based on Machine Vision Guiding

NASA Astrophysics Data System (ADS)

Zhang, Wenchang; Mei, Jiangping; Ding, Yabin

In this paper, a vision-based control strategy to perform high speed pick-and-place tasks on automation product line is proposed, and relevant control software is develop. Using Delta robot to control a sucker to grasp disordered objects from one moving conveyer and then place them on the other in order. CCD camera gets one picture every time the conveyer moves a distance of ds. Objects position and shape are got after image processing. Target tracking method based on "Servo motor + synchronous conveyer" is used to fulfill the high speed porting operation real time. Experiments conducted on Delta robot sorting system demonstrate the efficiency and validity of the proposed vision-control strategy.

Human-tracking strategies for a six-legged rescue robot based on distance and view

NASA Astrophysics Data System (ADS)

Pan, Yang; Gao, Feng; Qi, Chenkun; Chai, Xun

2016-03-01

Human tracking is an important issue for intelligent robotic control and can be used in many scenarios, such as robotic services and human-robot cooperation. Most of current human-tracking methods are targeted for mobile/tracked robots, but few of them can be used for legged robots. Two novel human-tracking strategies, view priority strategy and distance priority strategy, are proposed specially for legged robots, which enable them to track humans in various complex terrains. View priority strategy focuses on keeping humans in its view angle arrange with priority, while its counterpart, distance priority strategy, focuses on keeping human at a reasonable distance with priority. To evaluate these strategies, two indexes(average and minimum tracking capability) are defined. With the help of these indexes, the view priority strategy shows advantages compared with distance priority strategy. The optimization is done in terms of these indexes, which let the robot has maximum tracking capability. The simulation results show that the robot can track humans with different curves like square, circular, sine and screw paths. Two novel control strategies are proposed which specially concerning legged robot characteristics to solve human tracking problems more efficiently in rescue circumstances.

Strategy for increasing the participation of masyarakat peduli api in forest fire control

NASA Astrophysics Data System (ADS)

Ni’mah, N. L. K.; Herdiansyah, H.; Soesilo, T. E. B.; Mutia, E. F.

2018-03-01

Forest fires have negative impact on ecology, health, and damage economic activities. One of conservation areas facing the threat of forest fire is Gunung Ciremai National Park. This research aims to formulate a strategy to increase the participation of Masyarakat Peduli Api in the effort of forest fire control. This research use quantitative method with SWOT analysis. Expert consisting of representatives from the national park, Ministry of Environment and Forestry, and BPBD Kuningan Regency. An alternative strategy based on SWOT analysis is in quadrant 1 with coordinate point (0,39; 1,23). The position shows that sustainability of national park management through forest fire control can be done with an aggressive strategy. That is maximizing the strength that is owned with its potential as an ecotourism area to increase community motivation to engage in forest fire control activities. Provision of tourism management licenses will create employment opportunities and increase income for the community so it is expected to increase community participation to prevent the occurrence of forest fires rather than forest fire prevention.

Internal quality control: planning and implementation strategies.

PubMed

Westgard, James O

2003-11-01

The first essential in setting up internal quality control (IQC) of a test procedure in the clinical laboratory is to select the proper IQC procedure to implement, i.e. choosing the statistical criteria or control rules, and the number of control measurements, according to the quality required for the test and the observed performance of the method. Then the right IQC procedure must be properly implemented. This review focuses on strategies for planning and implementing IQC procedures in order to improve the quality of the IQC. A quantitative planning process is described that can be implemented with graphical tools such as power function or critical-error graphs and charts of operating specifications. Finally, a total QC strategy is formulated to minimize cost and maximize quality. A general strategy for IQC implementation is recommended that employs a three-stage design in which the first stage provides high error detection, the second stage low false rejection and the third stage prescribes the length of the analytical run, making use of an algorithm involving the average of normal patients' data.

Integrated Pest Management of Coffee Berry Borer: Strategies from Latin America that Could Be Useful for Coffee Farmers in Hawaii.

PubMed

Aristizábal, Luis F; Bustillo, Alex E; Arthurs, Steven P

2016-02-03

The coffee berry borer (CBB), Hypothenemus hampei Ferrari (Coleoptera: Curculionidae: Scolytinae) is the primary arthropod pest of coffee plantations worldwide. Since its detection in Hawaii (September 2010), coffee growers are facing financial losses due to reduced quality of coffee yields. Several control strategies that include cultural practices, biological control agents (parasitoids), chemical and microbial insecticides (entomopathogenic fungi), and a range of post-harvest sanitation practices have been conducted to manage CBB around the world. In addition, sampling methods including the use of alcohol based traps for monitoring CBB populations have been implemented in some coffee producing countries in Latin America. It is currently unclear which combination of CBB control strategies is optimal under economical, environmental, and sociocultural conditions of Hawaii. This review discusses components of an integrated pest management program for CBB. We focus on practical approaches to provide guidance to coffee farmers in Hawaii. Experiences of integrated pest management (IPM) of CBB learned from Latin America over the past 25 years may be relevant for establishing strategies of control that may fit under Hawaiian coffee farmers' conditions.

Uncertainty and sensitivity analysis of control strategies using the benchmark simulation model No1 (BSM1).

PubMed

Flores-Alsina, Xavier; Rodriguez-Roda, Ignasi; Sin, Gürkan; Gernaey, Krist V

2009-01-01

The objective of this paper is to perform an uncertainty and sensitivity analysis of the predictions of the Benchmark Simulation Model (BSM) No. 1, when comparing four activated sludge control strategies. The Monte Carlo simulation technique is used to evaluate the uncertainty in the BSM1 predictions, considering the ASM1 bio-kinetic parameters and influent fractions as input uncertainties while the Effluent Quality Index (EQI) and the Operating Cost Index (OCI) are focused on as model outputs. The resulting Monte Carlo simulations are presented using descriptive statistics indicating the degree of uncertainty in the predicted EQI and OCI. Next, the Standard Regression Coefficients (SRC) method is used for sensitivity analysis to identify which input parameters influence the uncertainty in the EQI predictions the most. The results show that control strategies including an ammonium (S(NH)) controller reduce uncertainty in both overall pollution removal and effluent total Kjeldahl nitrogen. Also, control strategies with an external carbon source reduce the effluent nitrate (S(NO)) uncertainty increasing both their economical cost and variability as a trade-off. Finally, the maximum specific autotrophic growth rate (micro(A)) causes most of the variance in the effluent for all the evaluated control strategies. The influence of denitrification related parameters, e.g. eta(g) (anoxic growth rate correction factor) and eta(h) (anoxic hydrolysis rate correction factor), becomes less important when a S(NO) controller manipulating an external carbon source addition is implemented.

Evaluation of stormwater micropollutant source control and end-of-pipe control strategies using an uncertainty-calibrated integrated dynamic simulation model.

PubMed

Vezzaro, L; Sharma, A K; Ledin, A; Mikkelsen, P S

2015-03-15

The estimation of micropollutant (MP) fluxes in stormwater systems is a fundamental prerequisite when preparing strategies to reduce stormwater MP discharges to natural waters. Dynamic integrated models can be important tools in this step, as they can be used to integrate the limited data provided by monitoring campaigns and to evaluate the performance of different strategies based on model simulation results. This study presents an example where six different control strategies, including both source-control and end-of-pipe treatment, were compared. The comparison focused on fluxes of heavy metals (copper, zinc) and organic compounds (fluoranthene). MP fluxes were estimated by using an integrated dynamic model, in combination with stormwater quality measurements. MP sources were identified by using GIS land usage data, runoff quality was simulated by using a conceptual accumulation/washoff model, and a stormwater retention pond was simulated by using a dynamic treatment model based on MP inherent properties. Uncertainty in the results was estimated with a pseudo-Bayesian method. Despite the great uncertainty in the MP fluxes estimated by the runoff quality model, it was possible to compare the six scenarios in terms of discharged MP fluxes, compliance with water quality criteria, and sediment accumulation. Source-control strategies obtained better results in terms of reduction of MP emissions, but all the simulated strategies failed in fulfilling the criteria based on emission limit values. The results presented in this study shows how the efficiency of MP pollution control strategies can be quantified by combining advanced modeling tools (integrated stormwater quality model, uncertainty calibration). Copyright © 2014 Elsevier Ltd. All rights reserved.

Mnemonic strategy training improves memory for object location associations in both healthy elderly and patients with amnestic mild cognitive impairment: a randomized, single-blind study

PubMed Central

Hampstead, Benjamin M.; Sathian, K.; Phillips, Pamela A.; Amaraneni, Akshay; Delaune, William R.; Stringer, Anthony Y.

2012-01-01

Objectives To evaluate the efficacy of mnemonic strategy training versus a matched-exposure control condition and also to examine the relationship between training-related gains, neuropsychological abilities, and medial temporal lobe volumetrics in patients with amnestic mild cognitive impairment (aMCI) and age-matched healthy controls. Methods Twenty-three of 45 screened healthy controls and 29 of 42 screened aMCI were randomized to mnemonic strategy or matched-exposure groups. Groups were run in parallel, with participants blind to the other intervention. All participants completed five sessions within two weeks. Memory testing for object-location associations was performed during sessions one and five and at a one-month follow-up. During sessions 2–4, participants received either mnemonic strategy training or a matched number of exposures with corrective feedback for a total of 45 object-location associations. Structural MRI was performed in most participants and medial temporal lobe volumetrics were acquired. Results Twenty-one healthy controls and 28 aMCI patients were included in data analysis. Mnemonic strategy training was significantly more beneficial than matched-exposure immediately after training, p =.006, pη2 = .16, and at one month, p<.001, pη2 = .35, regardless of diagnostic group (healthy controls or aMCI). Although aMCI patients demonstrated gains comparable to the healthy control groups, their overall performance generally remained reduced. Mnemonic strategy-related improvement was positively correlated with baseline memory and executive functioning and negatively with inferior lateral ventricle volume in aMCI patients; no significant relationships were evident in matched-exposure patients. Conclusions Mnemonic strategies effectively improve memory for specific content for at least one month in aMCI. PMID:22409311

Large-scale self-assembly of uniform submicron silver sulfide material driven by precise pressure control

NASA Astrophysics Data System (ADS)

Qi, Juanjuan; Chen, Ke; Zhang, Shuhao; Yang, Yun; Guo, Lin; Yang, Shihe

2017-03-01

The controllable self-assembly of nanosized building blocks into larger specific structures can provide an efficient method of synthesizing novel materials with excellent properties. The self-assembly of nanocrystals by assisted means is becoming an extremely active area of research, because it provides a method of producing large-scale advanced functional materials with potential applications in the areas of energy, electronics, optics, and biologics. In this study, we applied an efficient strategy, namely, the use of ‘pressure control’ to the assembly of silver sulfide (Ag2S) nanospheres with a diameter of approximately 33 nm into large-scale, uniform Ag2S sub-microspheres with a size of about 0.33 μm. More importantly, this strategy realizes the online control of the overall reaction system, including the pressure, reaction time, and temperature, and could also be used to easily fabricate other functional materials on an industrial scale. Moreover, the thermodynamics and kinetics parameters for the thermal decomposition of silver diethyldithiocarbamate (Ag(DDTC)) are also investigated to explore the formation mechanism of the Ag2S nanosized building blocks which can be assembled into uniform sub-micron scale architecture. As a method of producing sub-micron Ag2S particles by means of the pressure-controlled self-assembly of nanoparticles, we foresee this strategy being an efficient and universally applicable option for constructing other new building blocks and assembling novel and large functional micromaterials on an industrial scale.

Resources Management Strategy For Mud Crabs (Scylla spp.) In Pemalang Regency

NASA Astrophysics Data System (ADS)

Purnama Fitri, Aristi Dian; Boesono, Herry; Sabdono, Agus; Adlina, Nadia

2017-02-01

The aim of this research is to develop resources management strategies of mud crab (Scylla spp.) in Pemalang Regency. The method used is descriptive survey in a case study. This research used primary data and secondary data. Primary data were collected through field observations and in-depth interviews with key stakeholders. Secondary data were collected from related publications and documents issued by the competent institutions. SWOT Analysis was used to inventory the strengths, weaknesses, opportunities and threats. TOWS matrix was used to develop an alternative of resources management strategies. SWOT analysis was obtained by 6 alternative strategies that can be applied for optimization of fisheries development in Pemalang Regency. The strategies is the control of mud crab fishing gear, restricted size allowable in mud crab, control of mud crab fishing season, catch monitoring of mud crab, needs a management institutions which ensure the implementation of the regulation, and implementation for mud crab aquaculture. Each alternative strategy can be synergized to optimize the resources development in Pemalang Regency.

Active structural control of a floating wind turbine with a stroke-limited hybrid mass damper

NASA Astrophysics Data System (ADS)

Hu, Yaqi; He, Erming

2017-12-01

Floating wind turbines are subjected to more severe structural loads than fixed-bottom wind turbines due to additional degrees of freedom (DOFs) of their floating foundations. It's a promising way of using active structural control method to improve the structural responses of floating wind turbines. This paper investigates an active vibration control strategy for a barge-type floating wind turbine by setting a stroke-limited hybrid mass damper (HMD) in the turbine's nacelle. Firstly, a contact nonlinear modeling method for the floating wind turbine with clearance between the HMD and the stroke limiters is presented based on Euler-Lagrange's equations and an active control model of the whole system is established. The structural parameters are validated for the active control model and an equivalent load coefficient method is presented for identifying the wind and wave disturbances. Then, a state-feedback linear quadratic regulator (LQR) controller is designed to reduce vibration and loads of the wind turbine, and two optimization methods are combined to optimize the weighting coefficients when considering the stroke of the HMD and the active control power consumption as constraints. Finally, the designed controllers are implemented in high fidelity simulations under five typical wind and wave conditions. The results show that active HMD control strategy is shown to be achievable and the designed controllers could further reduce more vibration and loads of the wind turbine under the constraints of stroke limitation and power consumption. "V"-shaped distribution of the TMD suppression effect is inconsistent with the Weibull distribution in practical offshore floating wind farms, and the active HMD control could overcome this shortcoming of the passive TMD.

Frequency-Specific Fractal Analysis of Postural Control Accounts for Control Strategies

PubMed Central

Gilfriche, Pierre; Deschodt-Arsac, Véronique; Blons, Estelle; Arsac, Laurent M.

2018-01-01

Diverse indicators of postural control in Humans have been explored for decades, mostly based on the trajectory of the center-of-pressure. Classical approaches focus on variability, based on the notion that if a posture is too variable, the subject is not stable. Going deeper, an improved understanding of underlying physiology has been gained from studying variability in different frequency ranges, pointing to specific short-loops (proprioception), and long-loops (visuo-vestibular) in neural control. More recently, fractal analyses have proliferated and become useful additional metrics of postural control. They allowed identifying two scaling phenomena, respectively in short and long timescales. Here, we show that one of the most widely used methods for fractal analysis, Detrended Fluctuation Analysis, could be enhanced to account for scalings on specific frequency ranges. By computing and filtering a bank of synthetic fractal signals, we established how scaling analysis can be focused on specific frequency components. We called the obtained method Frequency-specific Fractal Analysis (FsFA) and used it to associate the two scaling phenomena of postural control to proprioceptive-based control loop and visuo-vestibular based control loop. After that, convincing arguments of method validity came from an application on the study of unaltered vs. altered postural control in athletes. Overall, the analysis suggests that at least two timescales contribute to postural control: a velocity-based control in short timescales relying on proprioceptive sensors, and a position-based control in longer timescales with visuo-vestibular sensors, which is a brand-new vision of postural control. Frequency-specific scaling exponents are promising markers of control strategies in Humans. PMID:29643816

The Systematic Development of an Internet-Based Smoking Cessation Intervention for Adults.

PubMed

Dalum, Peter; Brandt, Caroline Lyng; Skov-Ettrup, Lise; Tolstrup, Janne; Kok, Gerjo

2016-07-01

Objectives The objective of this project was to determine whether intervention mapping is a suitable strategy for developing an Internet- and text message-based smoking cessation intervention. Method We used the Intervention Mapping framework for planning health promotion programs. After a needs assessment, we identified important changeable determinants of cessation behavior, specified objectives for the intervention, selected theoretical methods for meeting our objectives, and operationalized change methods into practical intervention strategies. Results We found that "social cognitive theory," the "transtheoretical model/stages of change," "self-regulation theory," and "appreciative inquiry" were relevant theories for smoking cessation interventions. From these theories, we selected modeling/behavioral journalism, feedback, planning coping responses/if-then statements, gain frame/positive imaging, consciousness-raising, helping relationships, stimulus control, and goal-setting as suitable methods for an Internet- and text-based adult smoking cessation program. Furthermore, we identified computer tailoring as a useful strategy for adapting the intervention to individual users. Conclusion The Intervention Mapping method, with a clear link between behavioral goals, theoretical methods, and practical strategies and materials, proved useful for systematic development of a digital smoking cessation intervention for adults. © 2016 Society for Public Health Education.

An approach to the preliminary evaluation of Closed Ecological Life Support System (CELSS) scenarios and control strategies

NASA Technical Reports Server (NTRS)

Stahr, J. D.; Auslander, D. M.; Spear, R. C.; Young, G. E.

1982-01-01

Life support systems for manned space missions are discussed. A scenario analysis method was proposed for the initial step of comparing possible partial or total recycle scenarios. The method is discussed in detail.

Use of Recommended Search Strategies in Systematic Reviews and the Impact of Librarian Involvement: A Cross-Sectional Survey of Recent Authors

PubMed Central

Koffel, Jonathan B.

2015-01-01

Background Previous research looking at published systematic reviews has shown that their search strategies are often suboptimal and that librarian involvement, though recommended, is low. Confidence in the results, however, is limited due to poor reporting of search strategies the published articles. Objectives To more accurately measure the use of recommended search methods in systematic reviews, the levels of librarian involvement, and whether librarian involvement predicts the use of recommended methods. Methods A survey was sent to all authors of English-language systematic reviews indexed in the Database of Abstracts of Reviews of Effects (DARE) from January 2012 through January 2014. The survey asked about their use of search methods recommended by the Institute of Medicine, Cochrane Collaboration, and the Agency for Healthcare Research and Quality and if and how a librarian was involved in the systematic review. Rates of use of recommended methods and librarian involvement were summarized. The impact of librarian involvement on use of recommended methods was examined using a multivariate logistic regression. Results 1560 authors completed the survey. Use of recommended search methods ranged widely from 98% for use of keywords to 9% for registration in PROSPERO and were generally higher than in previous studies. 51% of studies involved a librarian, but only 64% acknowledge their assistance. Librarian involvement was significantly associated with the use of 65% of recommended search methods after controlling for other potential predictors. Odds ratios ranged from 1.36 (95% CI 1.06 to 1.75) for including multiple languages to 3.07 (95% CI 2.06 to 4.58) for using controlled vocabulary. Conclusions Use of recommended search strategies is higher than previously reported, but many methods are still under-utilized. Librarian involvement predicts the use of most methods, but their involvement is under-reported within the published article. PMID:25938454

The Effect of Using Metacognitive Strategies for Solving Geometry Problems on Students' Achievement and Attitude

ERIC Educational Resources Information Center

Mandaci Sahin, Seher; Kendir, Fatma

2013-01-01

The purpose of this study is to identify the effect of using metacognitive strategies for problem solving in "geometry" on fifth grade students' achievement, metacognitive skills and attitude. Experimental method was used with a pretest/posttest control group design. Firstly, both groups were subject to a pretest that was comprised of…

Reading Time Allocation Strategies and Working Memory Using Rapid Serial Visual Presentation

ERIC Educational Resources Information Center

Busler, Jessica N.; Lazarte, Alejandro A.

2017-01-01

Rapid serial visual presentation (RSVP) is a useful method for controlling the timing of text presentations and studying how readers' characteristics, such as working memory (WM) and reading strategies for time allocation, influence text recall. In the current study, a modified version of RSVP (Moving Window RSVP [MW-RSVP]) was used to induce…

Improving everyday prospective memory performance in older adults: comparing cognitive process and strategy training.

PubMed

Brom, Sarah Susanne; Kliegel, Matthias

2014-09-01

Considering the importance of prospective memory for independence in old age recently, research has started to examine interventions to reduce prospective memory errors. Two general approaches can be proposed: (a) process training of executive control associated with prospective memory functioning, and/or (b) strategy training to reduce executive task demands. The present study was the first to combine and compare both training methods in a sample of 62 community-dwelling older adults (60-86 years) and to explore their effects on an ecologically valid everyday life prospective memory task (here: regular blood pressure monitoring). Even though the training of executive control was successful in enhancing the trained ability, clear transfer effects on prospective memory performance could only be found for the strategy training. However, participants with low executive abilities benefited particularly from the implementation intention strategy. Conceptually, this supports models suggesting interactions between task demands and individual differences in executive control in explaining individual differences in prospective memory performance. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Implementation of real-time energy management strategy based on reinforcement learning for hybrid electric vehicles and simulation validation

PubMed Central

Kong, Zehui; Liu, Teng

2017-01-01

To further improve the fuel economy of series hybrid electric tracked vehicles, a reinforcement learning (RL)-based real-time energy management strategy is developed in this paper. In order to utilize the statistical characteristics of online driving schedule effectively, a recursive algorithm for the transition probability matrix (TPM) of power-request is derived. The reinforcement learning (RL) is applied to calculate and update the control policy at regular time, adapting to the varying driving conditions. A facing-forward powertrain model is built in detail, including the engine-generator model, battery model and vehicle dynamical model. The robustness and adaptability of real-time energy management strategy are validated through the comparison with the stationary control strategy based on initial transition probability matrix (TPM) generated from a long naturalistic driving cycle in the simulation. Results indicate that proposed method has better fuel economy than stationary one and is more effective in real-time control. PMID:28671967

Implementation of real-time energy management strategy based on reinforcement learning for hybrid electric vehicles and simulation validation.

PubMed

Kong, Zehui; Zou, Yuan; Liu, Teng

2017-01-01

To further improve the fuel economy of series hybrid electric tracked vehicles, a reinforcement learning (RL)-based real-time energy management strategy is developed in this paper. In order to utilize the statistical characteristics of online driving schedule effectively, a recursive algorithm for the transition probability matrix (TPM) of power-request is derived. The reinforcement learning (RL) is applied to calculate and update the control policy at regular time, adapting to the varying driving conditions. A facing-forward powertrain model is built in detail, including the engine-generator model, battery model and vehicle dynamical model. The robustness and adaptability of real-time energy management strategy are validated through the comparison with the stationary control strategy based on initial transition probability matrix (TPM) generated from a long naturalistic driving cycle in the simulation. Results indicate that proposed method has better fuel economy than stationary one and is more effective in real-time control.

Seaweed Bioactive Compounds against Pathogens and Microalgae: Potential Uses on Pharmacology and Harmful Algae Bloom Control.

PubMed

Zerrifi, Soukaina El Amrani; El Khalloufi, Fatima; Oudra, Brahim; Vasconcelos, Vitor

2018-02-09

Cyanobacteria are found globally due to their adaptation to various environments. The occurrence of cyanobacterial blooms is not a new phenomenon. The bloom-forming and toxin-producing species have been a persistent nuisance all over the world over the last decades. Evidence suggests that this trend might be attributed to a complex interplay of direct and indirect anthropogenic influences. To control cyanobacterial blooms, various strategies, including physical, chemical, and biological methods have been proposed. Nevertheless, the use of those strategies is usually not effective. The isolation of natural compounds from many aquatic and terrestrial plants and seaweeds has become an alternative approach for controlling harmful algae in aquatic systems. Seaweeds have received attention from scientists because of their bioactive compounds with antibacterial, antifungal, anti-microalgae, and antioxidant properties. The undesirable effects of cyanobacteria proliferations and potential control methods are here reviewed, focusing on the use of potent bioactive compounds, isolated from seaweeds, against microalgae and cyanobacteria growth.

Seaweed Bioactive Compounds against Pathogens and Microalgae: Potential Uses on Pharmacology and Harmful Algae Bloom Control

PubMed Central

Zerrifi, Soukaina El Amrani; El Khalloufi, Fatima; Oudra, Brahim; Vasconcelos, Vitor

2018-01-01

Cyanobacteria are found globally due to their adaptation to various environments. The occurrence of cyanobacterial blooms is not a new phenomenon. The bloom-forming and toxin-producing species have been a persistent nuisance all over the world over the last decades. Evidence suggests that this trend might be attributed to a complex interplay of direct and indirect anthropogenic influences. To control cyanobacterial blooms, various strategies, including physical, chemical, and biological methods have been proposed. Nevertheless, the use of those strategies is usually not effective. The isolation of natural compounds from many aquatic and terrestrial plants and seaweeds has become an alternative approach for controlling harmful algae in aquatic systems. Seaweeds have received attention from scientists because of their bioactive compounds with antibacterial, antifungal, anti-microalgae, and antioxidant properties. The undesirable effects of cyanobacteria proliferations and potential control methods are here reviewed, focusing on the use of potent bioactive compounds, isolated from seaweeds, against microalgae and cyanobacteria growth. PMID:29425153

A fuzzy gear shifting strategy for manual transmissions

NASA Astrophysics Data System (ADS)

Mashadi, B.; Kazemkhani, A.

2005-12-01

Governing parameters in decision making for gear changing of an automated manual transmission are discussed based on two different criteria, namely engine working conditions and driver's intention. By taking into consideration the effects of these parameters, gear shifting strategy is designed with the application of Fuzzy control method. The controller structure is formed in two layers. In the first layer two fuzzy inference modules are used to determine necessary outputs. In second layer a fuzzy inference module makes the decision of shifting by up-shift, downshift or maintain commands. The quality of Fuzzy controller behavior is examined by making use of ADVISOR software. It is shown that at different driving conditions the controller makes correct decisions for gear shifting accounting for dynamical requirements of vehicle. It is also shown that the controller based on both engine state and driver's intention eliminates unnecessary shiftings that are present when the intention is ignored. A micro-trip is designed in which a required speed in the form of a step function is demanded for the vehicle. Starting from rest both strategies change the gear to reach maximum speed more or less in a similar fashion. In deceleration phase, however, large differences are observed between the two strategies. The engine-state strategy is less sensitive to downshift, taking even unnecessary up shift decisions. The state-intention strategy, however, correctly interprets the driver's intention for decreasing speed and utilizes engine brake torque to reduce vehicle speed in a shorter time.

Light-inducible genetic engineering and control of non-homologous end-joining in industrial eukaryotic microorganisms: LML 3.0 and OFN 1.0.

PubMed

Zhang, Lei; Zhao, Xihua; Zhang, Guoxiu; Zhang, Jiajia; Wang, Xuedong; Zhang, Suping; Wang, Wei; Wei, Dongzhi

2016-02-09

Filamentous fungi play important roles in the production of plant cell-wall degrading enzymes. In recent years, homologous recombinant technologies have contributed significantly to improved enzymes production and system design of genetically manipulated strains. When introducing multiple gene deletions, we need a robust and convenient way to control selectable marker genes, especially when only a limited number of markers are available in filamentous fungi. Integration after transformation is predominantly nonhomologous in most fungi other than yeast. Fungal strains deficient in the non-homologous end-joining (NHEJ) pathway have limitations associated with gene function analyses despite they are excellent recipient strains for gene targets. We describe strategies and methods to address these challenges above and leverage the power of resilient NHEJ deficiency strains. We have established a foolproof light-inducible platform for one-step unmarked genetic modification in industrial eukaryotic microorganisms designated as 'LML 3.0', and an on-off control protocol of NHEJ pathway called 'OFN 1.0', using a synthetic light-switchable transactivation to control Cre recombinase-based excision and inversion. The methods provide a one-step strategy to sequentially modify genes without introducing selectable markers and NHEJ-deficiency. The strategies can be used to manipulate many biological processes in a wide range of eukaryotic cells.

Systems and methods for providing power to a load based upon a control strategy

DOEpatents

Perisic, Milun; Kajouke, Lateef A; Ransom, Ray M

2013-12-24

Systems and methods are provided for an electrical system. The electrical system includes a load, an interface configured to receive a voltage from a voltage source, and a controller configured to receive the voltage from the voltage source through the interface and to provide a voltage and current to the load. Wherein, when the controller is in a constant voltage mode, the controller provides a constant voltage to the load, when the controller is in a constant current mode, the controller provides a constant current to the load, and when the controller is in a constant power mode, the controller provides a constant power to the load.

A real-time comparison between direct control, sequential pattern recognition control and simultaneous pattern recognition control using a Fitts’ law style assessment procedure

PubMed Central

2014-01-01

Background Pattern recognition (PR) based strategies for the control of myoelectric upper limb prostheses are generally evaluated through offline classification accuracy, which is an admittedly useful metric, but insufficient to discuss functional performance in real time. Existing functional tests are extensive to set up and most fail to provide a challenging, objective framework to assess the strategy performance in real time. Methods Nine able-bodied and two amputee subjects gave informed consent and participated in the local Institutional Review Board approved study. We designed a two-dimensional target acquisition task, based on the principles of Fitts’ law for human motor control. Subjects were prompted to steer a cursor from the screen center of into a series of subsequently appearing targets of different difficulties. Three cursor control systems were tested, corresponding to three electromyography-based prosthetic control strategies: 1) amplitude-based direct control (the clinical standard of care), 2) sequential PR control, and 3) simultaneous PR control, allowing for a concurrent activation of two degrees of freedom (DOF). We computed throughput (bits/second), path efficiency (%), reaction time (second), and overshoot (%)) and used general linear models to assess significant differences between the strategies for each metric. Results We validated the proposed methodology by achieving very high coefficients of determination for Fitts’ law. Both PR strategies significantly outperformed direct control in two-DOF targets and were more intuitive to operate. In one-DOF targets, the simultaneous approach was the least precise. The direct control was efficient in one-DOF targets but cumbersome to operate in two-DOF targets through a switch-depended sequential cursor control. Conclusions We designed a test, capable of comprehensively describing prosthetic control strategies in real time. When implemented on control subjects, the test was able to capture statistically significant differences (p < 0.05) in control strategies when considering throughputs, path efficiencies and reaction times. Of particular note, we found statistically significant (p < 0.01) improvements in throughputs and path efficiencies with simultaneous PR when compared to direct control or sequential PR. Amputees could readily achieve the task; however a limited number of subjects was tested and a statistical analysis was not performed with that population. PMID:24886664

Identification of animal behavioral strategies by inverse reinforcement learning.

PubMed

Yamaguchi, Shoichiro; Naoki, Honda; Ikeda, Muneki; Tsukada, Yuki; Nakano, Shunji; Mori, Ikue; Ishii, Shin

2018-05-01

Animals are able to reach a desired state in an environment by controlling various behavioral patterns. Identification of the behavioral strategy used for this control is important for understanding animals' decision-making and is fundamental to dissect information processing done by the nervous system. However, methods for quantifying such behavioral strategies have not been fully established. In this study, we developed an inverse reinforcement-learning (IRL) framework to identify an animal's behavioral strategy from behavioral time-series data. We applied this framework to C. elegans thermotactic behavior; after cultivation at a constant temperature with or without food, fed worms prefer, while starved worms avoid the cultivation temperature on a thermal gradient. Our IRL approach revealed that the fed worms used both the absolute temperature and its temporal derivative and that their behavior involved two strategies: directed migration (DM) and isothermal migration (IM). With DM, worms efficiently reached specific temperatures, which explains their thermotactic behavior when fed. With IM, worms moved along a constant temperature, which reflects isothermal tracking, well-observed in previous studies. In contrast to fed animals, starved worms escaped the cultivation temperature using only the absolute, but not the temporal derivative of temperature. We also investigated the neural basis underlying these strategies, by applying our method to thermosensory neuron-deficient worms. Thus, our IRL-based approach is useful in identifying animal strategies from behavioral time-series data and could be applied to a wide range of behavioral studies, including decision-making, in other organisms.

Barriers to Participation in a Community-Based Program to Control Transmission of Taenia solium in Peru.

PubMed

Beam, Michelle; Spencer, Angela; Fernandez, Lauralee; Atto, Ruth; Muro, Claudio; Vilchez, Percy; Gamboa, Ricardo; Olaya, Sandra; Ayvar, Viterbo; Gonzalez, Armando E; Garcia, Hector H; O'Neal, Seth E; For The Cysticercosis Working Group In Peru

2018-04-16

Infection of the brain with Taenia solium larvae (neurocysticercosis) is a leading cause of preventable epilepsy worldwide. Effective and sustainable strategies to control parasite transmission in rural endemic communities are needed to prevent the disease. Surveillance and targeted intervention around infected pigs (ring control strategy) have been shown to be effective when carried out by research teams. However, this strategy has not been implemented or tested as a community-based program. In this small trial in northern Peru, eight villages were randomly assigned to community-led surveillance and treatment (five villages, 997 residents) or control (three villages, 1,192 residents). In intervention villages, community-led surveillance and reporting were promoted by community health workers, radio advertisement, and school and household education. Each suspected pig infection was verified, with confirmed cases resulting in treatment with niclosamide for taeniasis and oxfendazole for pigs in clusters of homes nearby. No incentives beyond human and pig treatment were offered. Control villages received basic disease education but no treatment intervention in response to reports. Despite 14 case reports, community-based replication of ring control strategy did not replicate prior results. After 12 months, there was no change in seroincidence in intervention villages between the baseline and study end, and no difference compared with control villages. There was no difference in prevalence of taeniasis or porcine cysticercosis at study end. Community members described lack of knowledge as the main reason for not reporting infected pigs. Further exploration of methods to transfer ring strategy and other control interventions for cysticercosis to the community is needed.

Enhancing evidence-based diabetes and chronic disease control among local health departments: a multi-phase dissemination study with a stepped-wedge cluster randomized trial component.

PubMed

Parks, Renee G; Tabak, Rachel G; Allen, Peg; Baker, Elizabeth A; Stamatakis, Katherine A; Poehler, Allison R; Yan, Yan; Chin, Marshall H; Harris, Jenine K; Dobbins, Maureen; Brownson, Ross C

2017-10-18

The rates of diabetes and prediabetes in the USA are growing, significantly impacting the quality and length of life of those diagnosed and financially burdening society. Premature death and disability can be prevented through implementation of evidence-based programs and policies (EBPPs). Local health departments (LHDs) are uniquely positioned to implement diabetes control EBPPs because of their knowledge of, and focus on, community-level needs, contexts, and resources. There is a significant gap, however, between known diabetes control EBPPs and actual diabetes control activities conducted by LHDs. The purpose of this study is to determine how best to support the use of evidence-based public health for diabetes (and related chronic diseases) control among local-level public health practitioners. This paper describes the methods for a two-phase study with a stepped-wedge cluster randomized trial that will evaluate dissemination strategies to increase the uptake of public health knowledge and EBPPs for diabetes control among LHDs. Phase 1 includes development of measures to assess practitioner views on and organizational supports for evidence-based public health, data collection using a national online survey of LHD chronic disease practitioners, and a needs assessment of factors influencing the uptake of diabetes control EBPPs among LHDs within one state in the USA. Phase 2 involves conducting a stepped-wedge cluster randomized trial to assess effectiveness of dissemination strategies with local-level practitioners at LHDs to enhance capacity and organizational support for evidence-based diabetes prevention and control. Twelve LHDs will be selected and randomly assigned to one of the three groups that cross over from usual practice to receive the intervention (dissemination) strategies at 8-month intervals; the intervention duration for groups ranges from 8 to 24 months. Intervention (dissemination) strategies may include multi-day in-person workshops, electronic information exchange methods, technical assistance through a knowledge broker, and organizational changes to support evidence-based public health approaches. Evaluation methods comprise surveys at baseline and the three crossover time points, abstraction of local-level diabetes and chronic disease control program plans and progress reports, and social network analysis to understand the relationships and contextual issues that influence EBPP adoption. ClinicalTrial.gov, NCT03211832.

Further developments in the controlled growth approach for optimal structural synthesis

NASA Technical Reports Server (NTRS)

Hajela, P.

1982-01-01

It is pointed out that the use of nonlinear programming methods in conjunction with finite element and other discrete analysis techniques have provided a powerful tool in the domain of optimal structural synthesis. The present investigation is concerned with new strategies which comprise an extension to the controlled growth method considered by Hajela and Sobieski-Sobieszczanski (1981). This method proposed an approach wherein the standard nonlinear programming (NLP) methodology of working with a very large number of design variables was replaced by a sequence of smaller optimization cycles, each involving a single 'dominant' variable. The current investigation outlines some new features. Attention is given to a modified cumulative constraint representation which is defined in both the feasible and infeasible domain of the design space. Other new features are related to the evaluation of the 'effectiveness measure' on which the choice of the dominant variable and the linking strategy is based.

A rule-based phase control methodology for a slider-crank wave energy converter power take-off system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sang, Yuanrui; Karayaka, H. Bora; Yan, Yanjun

The slider crank is a proven mechanical linkage system with a long history of successful applications, and the slider-crank ocean wave energy converter (WEC) is a type of WEC that converts linear motion into rotation. This paper presents a control algorithm for a slider-crank WEC. In this study, a time-domain hydrodynamic analysis is adopted, and an AC synchronous machine is used in the power take-off system to achieve relatively high system performance. Also, a rule-based phase control strategy is applied to maximize energy extraction, making the system suitable for not only regular sinusoidal waves but also irregular waves. Simulations aremore » carried out under regular sinusoidal wave and synthetically produced irregular wave conditions; performance validations are also presented with high-precision, real ocean wave surface elevation data. The influences of significant wave height, and peak period upon energy extraction of the system are studied. Energy extraction results using the proposed method are compared to those of the passive loading and complex conjugate control strategies; results show that the level of energy extraction is between those of the passive loading and complex conjugate control strategies, and the suboptimal nature of this control strategy is verified.« less

Operational efficiency and sustainability of vector control of malaria and dengue: descriptive case studies from the Philippines

PubMed Central

2012-01-01

Background Analysis is lacking on the management of vector control systems in disease-endemic countries with respect to the efficiency and sustainability of operations. Methods Three locations were selected, at the scale of province, municipality and barangay (i.e. village). Data on disease incidence, programme activities, and programme management were collected on-site through meetings and focus group discussions. Results Adaptation of disease control strategies to the epidemiological situation per barangay, through micro-stratification, brings gains in efficiency, but should be accompanied by further capacity building on local situational analysis for better selection and targeting of vector control interventions within the barangay. An integrated approach to vector control, aiming to improve the rational use of resources, was evident with a multi-disease strategy for detection and response, and by the use of combinations of vector control methods. Collaboration within the health sector was apparent from the involvement of barangay health workers, re-orientation of job descriptions and the creation of a disease surveillance unit. The engagement of barangay leaders and use of existing community structures helped mobilize local resources and voluntary services for vector control. In one location, local authorities and the community were involved in the planning, implementation and evaluation of malaria control, which triggered local programme ownership. Conclusions Strategies that contributed to an improved efficiency and sustainability of vector control operations were: micro-stratification, integration of vector control within the health sector, a multi-disease approach, involvement of local authorities, and empowerment of communities. Capacity building on situational analysis and vector surveillance should be addressed through national policy and guidelines. PMID:22873707

Assessing the impact of breeding strategies on inherited disorders and genetic diversity in dogs.

PubMed

Leroy, Grégoire; Rognon, Xavier

2012-12-01

In the context of management of genetic diversity and control of genetic disorders within dog breeds, a method is proposed for assessing the impact of different breeding strategies that takes into account the genealogical information specific to a given breed. Two types of strategies were investigated: (1) eradication of an identified monogenic recessive disorder, taking into account three different mating limitations and various initial allele frequencies; and (2) control of the population sire effect by limiting the number of offspring per reproducer. The method was tested on four dog breeds: Braque Saint Germain, Berger des Pyrénées, Coton de Tulear and Epagneul Breton. Breeding policies, such as the removal of all carriers from the reproduction pool, may have a range of effects on genetic diversity, depending on the breed and the frequency of deleterious alleles. Limiting the number of offspring per reproducer may also have a positive impact on genetic diversity. Copyright © 2012 Elsevier Ltd. All rights reserved.

A time domain inverse dynamic method for the end point tracking control of a flexible manipulator

NASA Technical Reports Server (NTRS)

Kwon, Dong-Soo; Book, Wayne J.

1991-01-01

The inverse dynamic equation of a flexible manipulator was solved in the time domain. By dividing the inverse system equation into the causal part and the anticausal part, we calculated the torque and the trajectories of all state variables for a given end point trajectory. The interpretation of this method in the frequency domain was explained in detail using the two-sided Laplace transform and the convolution integral. The open loop control of the inverse dynamic method shows an excellent result in simulation. For real applications, a practical control strategy is proposed by adding a feedback tracking control loop to the inverse dynamic feedforward control, and its good experimental performance is presented.

An Optimal Control Strategy for DC Bus Voltage Regulation in Photovoltaic System with Battery Energy Storage

PubMed Central

Daud, Muhamad Zalani; Mohamed, Azah; Hannan, M. A.

2014-01-01

This paper presents an evaluation of an optimal DC bus voltage regulation strategy for grid-connected photovoltaic (PV) system with battery energy storage (BES). The BES is connected to the PV system DC bus using a DC/DC buck-boost converter. The converter facilitates the BES power charge/discharge to compensate for the DC bus voltage deviation during severe disturbance conditions. In this way, the regulation of DC bus voltage of the PV/BES system can be enhanced as compared to the conventional regulation that is solely based on the voltage-sourced converter (VSC). For the grid side VSC (G-VSC), two control methods, namely, the voltage-mode and current-mode controls, are applied. For control parameter optimization, the simplex optimization technique is applied for the G-VSC voltage- and current-mode controls, including the BES DC/DC buck-boost converter controllers. A new set of optimized parameters are obtained for each of the power converters for comparison purposes. The PSCAD/EMTDC-based simulation case studies are presented to evaluate the performance of the proposed optimized control scheme in comparison to the conventional methods. PMID:24883374

An optimal control strategy for DC bus voltage regulation in photovoltaic system with battery energy storage.

PubMed

Daud, Muhamad Zalani; Mohamed, Azah; Hannan, M A

2014-01-01

This paper presents an evaluation of an optimal DC bus voltage regulation strategy for grid-connected photovoltaic (PV) system with battery energy storage (BES). The BES is connected to the PV system DC bus using a DC/DC buck-boost converter. The converter facilitates the BES power charge/discharge to compensate for the DC bus voltage deviation during severe disturbance conditions. In this way, the regulation of DC bus voltage of the PV/BES system can be enhanced as compared to the conventional regulation that is solely based on the voltage-sourced converter (VSC). For the grid side VSC (G-VSC), two control methods, namely, the voltage-mode and current-mode controls, are applied. For control parameter optimization, the simplex optimization technique is applied for the G-VSC voltage- and current-mode controls, including the BES DC/DC buck-boost converter controllers. A new set of optimized parameters are obtained for each of the power converters for comparison purposes. The PSCAD/EMTDC-based simulation case studies are presented to evaluate the performance of the proposed optimized control scheme in comparison to the conventional methods.

Numerical solution of a conspicuous consumption model with constant control delay☆

PubMed Central

Huschto, Tony; Feichtinger, Gustav; Hartl, Richard F.; Kort, Peter M.; Sager, Sebastian; Seidl, Andrea

2011-01-01

We derive optimal pricing strategies for conspicuous consumption products in periods of recession. To that end, we formulate and investigate a two-stage economic optimal control problem that takes uncertainty of the recession period length and delay effects of the pricing strategy into account. This non-standard optimal control problem is difficult to solve analytically, and solutions depend on the variable model parameters. Therefore, we use a numerical result-driven approach. We propose a structure-exploiting direct method for optimal control to solve this challenging optimization problem. In particular, we discretize the uncertainties in the model formulation by using scenario trees and target the control delays by introduction of slack control functions. Numerical results illustrate the validity of our approach and show the impact of uncertainties and delay effects on optimal economic strategies. During the recession, delayed optimal prices are higher than the non-delayed ones. In the normal economic period, however, this effect is reversed and optimal prices with a delayed impact are smaller compared to the non-delayed case. PMID:22267871

Two nonlinear control schemes contrasted on a hydrodynamiclike model

NASA Technical Reports Server (NTRS)

Keefe, Laurence R.

1993-01-01

The principles of two flow control strategies, those of Huebler (Luescher and Huebler, 1989) and of Ott et al. (1990) are discussed, and the two schemes are compared for their ability to control shear flow, using fully developed and transitional solutions of the Ginzburg-Landau equation as models for such flows. It was found that the effectiveness of both methods in obtaining control of fully developed flows depended strongly on the 'distance' in state space between the uncontrolled flow and goal dynamics. There were conceptual difficulties in applying the Ott et al. method to transitional convectively unstable flows. On the other hand, the Huebler method worked well, within certain limitations, although at a large cost in energy terms.

Use of recommended search strategies in systematic reviews and the impact of librarian involvement: a cross-sectional survey of recent authors.

PubMed

Koffel, Jonathan B

2015-01-01

Previous research looking at published systematic reviews has shown that their search strategies are often suboptimal and that librarian involvement, though recommended, is low. Confidence in the results, however, is limited due to poor reporting of search strategies the published articles. To more accurately measure the use of recommended search methods in systematic reviews, the levels of librarian involvement, and whether librarian involvement predicts the use of recommended methods. A survey was sent to all authors of English-language systematic reviews indexed in the Database of Abstracts of Reviews of Effects (DARE) from January 2012 through January 2014. The survey asked about their use of search methods recommended by the Institute of Medicine, Cochrane Collaboration, and the Agency for Healthcare Research and Quality and if and how a librarian was involved in the systematic review. Rates of use of recommended methods and librarian involvement were summarized. The impact of librarian involvement on use of recommended methods was examined using a multivariate logistic regression. 1560 authors completed the survey. Use of recommended search methods ranged widely from 98% for use of keywords to 9% for registration in PROSPERO and were generally higher than in previous studies. 51% of studies involved a librarian, but only 64% acknowledge their assistance. Librarian involvement was significantly associated with the use of 65% of recommended search methods after controlling for other potential predictors. Odds ratios ranged from 1.36 (95% CI 1.06 to 1.75) for including multiple languages to 3.07 (95% CI 2.06 to 4.58) for using controlled vocabulary. Use of recommended search strategies is higher than previously reported, but many methods are still under-utilized. Librarian involvement predicts the use of most methods, but their involvement is under-reported within the published article.

Content and strategy in syllogistic reasoning.

PubMed

Marrero, Hipólito; Elena, Gámez

2004-09-01

Syllogistic reasoning has been investigated as a general deductive process (Johnson-Laird & Byrne, 1991; Revlis, 1975; Rips, 1994). However, several studies have demonstrated the role of cognitive strategies in this type of reasoning. These strategies focus on the method used by the participants (Ford, 1995; Gilhooly, Logie, Wetherick, & Wynn, 1993) and strategies related to different interpretations of the quantified premises (Roberts, Newstead, & Griggs, 2001). In this paper, we propose that content (as well as individual cognitive differences) is an important factor in inducing a certain strategy or method for syllogistic resolution. Specifically, we suggest that syllogisms with a causal conditional premise that can be extended by an agency premise induce the use of a conditional method. To demonstrate this, we carried out two experiments. Experiment 1 provided evidence that this type of syllogism leads participants to draw the predicted conditional conclusions, in contrast with control content syllogisms. In Experiment 2, we demonstrated that the drawing of conditional conclusions is based on a causal conditional to an agent representation of the syllogism premises. These results support the role of content as inducing a particular strategy for syllogistic resolution. The implications of these results are discussed.

A New Unified Analysis of Estimate Errors by Model-Matching Phase-Estimation Methods for Sensorless Drive of Permanent-Magnet Synchronous Motors and New Trajectory-Oriented Vector Control, Part II

NASA Astrophysics Data System (ADS)

Shinnaka, Shinji

This paper presents a new unified analysis of estimate errors by model-matching extended-back-EMF estimation methods for sensorless drive of permanent-magnet synchronous motors. Analytical solutions about estimate errors, whose validity is confirmed by numerical experiments, are rich in universality and applicability. As an example of universality and applicability, a new trajectory-oriented vector control method is proposed, which can realize directly quasi-optimal strategy minimizing total losses with no additional computational loads by simply orienting one of vector-control coordinates to the associated quasi-optimal trajectory. The coordinate orientation rule, which is analytically derived, is surprisingly simple. Consequently the trajectory-oriented vector control method can be applied to a number of conventional vector control systems using model-matching extended-back-EMF estimation methods.

Managing population health to prevent and detect cancer and non-communicable diseases.

PubMed

Bryant, Heather; Shin, Hai Rim; Forman, David; Stevanovic, Vladimir; Park, Sohee; Burton, Robert; Varghese, Cherian; Ullrich, Andreas; Sutcliffe, Catherine; Sutcliffe, Simon

2012-01-01

The goals of cancer control strategies are generally uniform across all constituencies and are to reduce cancer incidence, reduce cancer mortality, and improve quality of life for those affected by cancer. A well-constructed strategy will ensure that all of its elements can ultimately be connected to one of these goals. When a cancer control strategy is being implemented, it is essential to map progress towards these goals; without mapping progress, it is impossible to assess which components of the strategy require more attention or resources and which are not having the desired effect and need to be re-evaluated. In order to monitor and evaluate these strategies, systems need to be put in place to collect data and the appropriate indicators of performance need to be identified. Session 2 of the 4th International Cancer Control Congress (ICCC-4) focused on how to manage population health to prevent and detect cancers and non-communicable diseases through two plenary presentations and four interactive workshop discussions: 1) registries, measurement, and management in cancer control; 2) use of information for planning and evaluating screening and early detection programs; 3) alternative models for promoting community health, integrated care and illness management; and 4) control of non-communicable diseases. Workshop discussions highlighted that population based cancer registries are fundamental to understanding the cancer burden within a country. However, many countries in Africa, Asia, and South/ Central America do not have them in place. A new global initiative is underway, which brings together several international agencies, and aims to establish six IARC regional registration resource centres over the next five years. These will provide training, support, infrastructure and advocacy to local networks of cancer registries, and, it is hoped, improve the host countries' ability to assess and act on cancer issues within their jurisdictions. Multiple methods of programme evaluation were presented across workshops, but all were attuned to both the resource base and the specific questions to be addressed. Where innovative strategies were being tested, customized evaluation strategies should be undertaken. Where programmes are well-developed and data is being collected for evaluation, there is the opportunity for sophisticated analytical methods to be used to pinpoint specific areas or delivery sites for future quality improvement. Finally, unique opportunities now exist to integrate the strategies developed in cancer control and evaluation with those under development for other non-communicable diseases. This area will likely be one for future development.

An accurate reactive power control study in virtual flux droop control

NASA Astrophysics Data System (ADS)

Wang, Aimeng; Zhang, Jia

2017-12-01

This paper investigates the problem of reactive power sharing based on virtual flux droop method. Firstly, flux droop control method is derived, where complicated multiple feedback loops and parameter regulation are avoided. Then, the reasons for inaccurate reactive power sharing are theoretically analyzed. Further, a novel reactive power control scheme is proposed which consists of three parts: compensation control, voltage recovery control and flux droop control. Finally, the proposed reactive power control strategy is verified in a simplified microgrid model with two parallel DGs. The simulation results show that the proposed control scheme can achieve accurate reactive power sharing and zero deviation of voltage. Meanwhile, it has some advantages of simple control and excellent dynamic and static performance.

A system framework of inter-enterprise machining quality control based on fractal theory

NASA Astrophysics Data System (ADS)

Zhao, Liping; Qin, Yongtao; Yao, Yiyong; Yan, Peng

2014-03-01

In order to meet the quality control requirement of dynamic and complicated product machining processes among enterprises, a system framework of inter-enterprise machining quality control based on fractal was proposed. In this system framework, the fractal-specific characteristic of inter-enterprise machining quality control function was analysed, and the model of inter-enterprise machining quality control was constructed by the nature of fractal structures. Furthermore, the goal-driven strategy of inter-enterprise quality control and the dynamic organisation strategy of inter-enterprise quality improvement were constructed by the characteristic analysis on this model. In addition, the architecture of inter-enterprise machining quality control based on fractal was established by means of Web service. Finally, a case study for application was presented. The result showed that the proposed method was available, and could provide guidance for quality control and support for product reliability in inter-enterprise machining processes.

Model-free adaptive speed control on travelling wave ultrasonic motor

NASA Astrophysics Data System (ADS)

Di, Sisi; Li, Huafeng

2018-01-01

This paper introduced a new data-driven control (DDC) method for the speed control of ultrasonic motor (USM). The model-free adaptive control (MFAC) strategy was presented in terms of its principles, algorithms, and parameter selection. To verify the efficiency of the proposed method, a speed-frequency-time model, which contained all the measurable nonlinearity and uncertainties based on experimental data was established for simulation to mimic the USM operation system. Furthermore, the model was identified using particle swarm optimization (PSO) method. Then, the control of the simulated system using MFAC was evaluated under different expectations in terms of overshoot, rise time and steady-state error. Finally, the MFAC results were compared with that of proportion iteration differentiation (PID) to demonstrate its advantages in controlling general random system.

Chemosterilants for Control of Insects and Insect Vectors of Disease.

PubMed

Baxter, Richard H G

2016-10-01

Both historically and at present, vector control is the most generally effective means of controlling malaria transmission. Insecticides are the predominant method of vector control, but the sterile insect technique (SIT) is a complementary strategy with a successful track record in both agricultural and public health sectors. Strategies of genetic and radiation-induced sterilization of Anopheles have to date been limited by logistical and/or regulatory hurdles. A safe and effective mosquito chemosterilant would therefore be of major utility to future deployment of SIT for malaria control. Here we review the prior and current use of chemosterilants in SIT, and assess the potential for future research. Recent genomic and proteomic studies reveal opportunities for specific targeting of seminal fluid proteins, and the capacity to interfere with sperm motility and storage in the female.

On the use of musculoskeletal models to interpret motor control strategies from performance data

NASA Astrophysics Data System (ADS)

Cheng, Ernest J.; Loeb, Gerald E.

2008-06-01

The intrinsic viscoelastic properties of muscle are central to many theories of motor control. Much of the debate over these theories hinges on varying interpretations of these muscle properties. In the present study, we describe methods whereby a comprehensive musculoskeletal model can be used to make inferences about motor control strategies that would account for behavioral data. Muscle activity and kinematic data from a monkey were recorded while the animal performed a single degree-of-freedom pointing task in the presence of pseudo-random torque perturbations. The monkey's movements were simulated by a musculoskeletal model with accurate representations of musculotendon morphometry and contractile properties. The model was used to quantify the impedance of the limb while moving rapidly, the differential action of synergistic muscles, the relative contribution of reflexes to task performance and the completeness of recorded EMG signals. Current methods to address these issues in the absence of musculoskeletal models were compared with the methods used in the present study. We conclude that musculoskeletal models and kinetic analysis can improve the interpretation of kinematic and electrophysiological data, in some cases by illuminating shortcomings of the experimental methods or underlying assumptions that may otherwise escape notice.

Hierarchical Shared Control of Cane-Type Walking-Aid Robot

PubMed Central

Tao, Chunjing

2017-01-01

A hierarchical shared-control method of the walking-aid robot for both human motion intention recognition and the obstacle emergency-avoidance method based on artificial potential field (APF) is proposed in this paper. The human motion intention is obtained from the interaction force measurements of the sensory system composed of 4 force-sensing registers (FSR) and a torque sensor. Meanwhile, a laser-range finder (LRF) forward is applied to detect the obstacles and try to guide the operator based on the repulsion force calculated by artificial potential field. An obstacle emergency-avoidance method which comprises different control strategies is also assumed according to the different states of obstacles or emergency cases. To ensure the user's safety, the hierarchical shared-control method combines the intention recognition method with the obstacle emergency-avoidance method based on the distance between the walking-aid robot and the obstacles. At last, experiments validate the effectiveness of the proposed hierarchical shared-control method. PMID:29093805

Experimental comparisons of hypothesis test and moving average based combustion phase controllers.

PubMed

Gao, Jinwu; Wu, Yuhu; Shen, Tielong

2016-11-01

For engine control, combustion phase is the most effective and direct parameter to improve fuel efficiency. In this paper, the statistical control strategy based on hypothesis test criterion is discussed. Taking location of peak pressure (LPP) as combustion phase indicator, the statistical model of LPP is first proposed, and then the controller design method is discussed on the basis of both Z and T tests. For comparison, moving average based control strategy is also presented and implemented in this study. The experiments on a spark ignition gasoline engine at various operating conditions show that the hypothesis test based controller is able to regulate LPP close to set point while maintaining the rapid transient response, and the variance of LPP is also well constrained. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Identification of control targets in Boolean molecular network models via computational algebra.

PubMed

Murrugarra, David; Veliz-Cuba, Alan; Aguilar, Boris; Laubenbacher, Reinhard

2016-09-23

Many problems in biomedicine and other areas of the life sciences can be characterized as control problems, with the goal of finding strategies to change a disease or otherwise undesirable state of a biological system into another, more desirable, state through an intervention, such as a drug or other therapeutic treatment. The identification of such strategies is typically based on a mathematical model of the process to be altered through targeted control inputs. This paper focuses on processes at the molecular level that determine the state of an individual cell, involving signaling or gene regulation. The mathematical model type considered is that of Boolean networks. The potential control targets can be represented by a set of nodes and edges that can be manipulated to produce a desired effect on the system. This paper presents a method for the identification of potential intervention targets in Boolean molecular network models using algebraic techniques. The approach exploits an algebraic representation of Boolean networks to encode the control candidates in the network wiring diagram as the solutions of a system of polynomials equations, and then uses computational algebra techniques to find such controllers. The control methods in this paper are validated through the identification of combinatorial interventions in the signaling pathways of previously reported control targets in two well studied systems, a p53-mdm2 network and a blood T cell lymphocyte granular leukemia survival signaling network. Supplementary data is available online and our code in Macaulay2 and Matlab are available via http://www.ms.uky.edu/~dmu228/ControlAlg . This paper presents a novel method for the identification of intervention targets in Boolean network models. The results in this paper show that the proposed methods are useful and efficient for moderately large networks.

Design and analysis of multiple diseases genome-wide association studies without controls.

PubMed

Chen, Zhongxue; Huang, Hanwen; Ng, Hon Keung Tony

2012-11-15

In genome-wide association studies (GWAS), multiple diseases with shared controls is one of the case-control study designs. If data obtained from these studies are appropriately analyzed, this design can have several advantages such as improving statistical power in detecting associations and reducing the time and cost in the data collection process. In this paper, we propose a study design for GWAS which involves multiple diseases but without controls. We also propose corresponding statistical data analysis strategy for GWAS with multiple diseases but no controls. Through a simulation study, we show that the statistical association test with the proposed study design is more powerful than the test with single disease sharing common controls, and it has comparable power to the overall test based on the whole dataset including the controls. We also apply the proposed method to a real GWAS dataset to illustrate the methodologies and the advantages of the proposed design. Some possible limitations of this study design and testing method and their solutions are also discussed. Our findings indicate that the proposed study design and statistical analysis strategy could be more efficient than the usual case-control GWAS as well as those with shared controls. Copyright © 2012 Elsevier B.V. All rights reserved.

Predictive control strategy of a gas turbine for improvement of combined cycle power plant dynamic performance and efficiency.

PubMed

Mohamed, Omar; Wang, Jihong; Khalil, Ashraf; Limhabrash, Marwan

2016-01-01

This paper presents a novel strategy for implementing model predictive control (MPC) to a large gas turbine power plant as a part of our research progress in order to improve plant thermal efficiency and load-frequency control performance. A generalized state space model for a large gas turbine covering the whole steady operational range is designed according to subspace identification method with closed loop data as input to the identification algorithm. Then the model is used in developing a MPC and integrated into the plant existing control strategy. The strategy principle is based on feeding the reference signals of the pilot valve, natural gas valve, and the compressor pressure ratio controller with the optimized decisions given by the MPC instead of direct application of the control signals. If the set points for the compressor controller and turbine valves are sent in a timely manner, there will be more kinetic energy in the plant to release faster responses on the output and the overall system efficiency is improved. Simulation results have illustrated the feasibility of the proposed application that has achieved significant improvement in the frequency variations and load following capability which are also translated to be improvements in the overall combined cycle thermal efficiency of around 1.1 % compared to the existing one.

Frequency control of wind turbine in power system

NASA Astrophysics Data System (ADS)

Xu, Huawei

2018-06-01

In order to improve the stability of the overall frequency of the power system, automatic power generation control and secondary frequency adjustment were applied. Automatic power generation control was introduced into power generation planning. A dual-fed wind generator power regulation model suitable for secondary frequency regulation was established. The results showed that this method satisfied the basic requirements of frequency regulation control of large-scale wind power access power systems and improved the stability and reliability of power system operation. Therefore, this system frequency control method and strategy is relatively simple. The effect is significant. The system frequency can quickly reach a steady state. It is worth applying and promoting.

On stochastic control and optimal measurement strategies. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Kramer, L. C.

1971-01-01

The control of stochastic dynamic systems is studied with particular emphasis on those which influence the quality or nature of the measurements which are made to effect control. Four main areas are discussed: (1) the meaning of stochastic optimality and the means by which dynamic programming may be applied to solve a combined control/measurement problem; (2) a technique by which it is possible to apply deterministic methods, specifically the minimum principle, to the study of stochastic problems; (3) the methods described are applied to linear systems with Gaussian disturbances to study the structure of the resulting control system; and (4) several applications are considered.

Evaluation of strategies to control Fab light chain dimer during mammalian expression and purification: A universal one-step process for purification of correctly assembled Fab.

PubMed

Spooner, Jennifer; Keen, Jenny; Nayyar, Kalpana; Birkett, Neil; Bond, Nicholas; Bannister, David; Tigue, Natalie; Higazi, Daniel; Kemp, Benjamin; Vaughan, Tristan; Kippen, Alistair; Buchanan, Andrew

2015-07-01

Fabs are an important class of antibody fragment as both research reagents and therapeutic agents. There are a plethora of methods described for their recombinant expression and purification. However, these do not address the issue of excessive light chain production that forms light chain dimers nor do they describe a universal purification strategy. Light chain dimer impurities and the absence of a universal Fab purification strategy present persistent challenges for biotechnology applications using Fabs, particularly around the need for bespoke purification strategies. This study describes methods to address light chain dimer formation during Fab expression and identifies a novel CH 1 affinity resin as a simple and efficient one-step purification for correctly assembled Fab. © 2015 Wiley Periodicals, Inc.

Simulation based optimized beam velocity in additive manufacturing

NASA Astrophysics Data System (ADS)

Vignat, Frédéric; Béraud, Nicolas; Villeneuve, François

2017-08-01

Manufacturing good parts with additive technologies rely on melt pool dimension and temperature and are controlled by manufacturing strategies often decided on machine side. Strategies are built on beam path and variable energy input. Beam path are often a mix of contour and hatching strategies filling the contours at each slice. Energy input depend on beam intensity and speed and is determined from simple thermal models to control melt pool dimensions and temperature and ensure porosity free material. These models take into account variation in thermal environment such as overhanging surfaces or back and forth hatching path. However not all the situations are correctly handled and precision is limited. This paper proposes new method to determine energy input from full built chamber 3D thermal simulation. Using the results of the simulation, energy is modified to keep melt pool temperature in a predetermined range. The paper present first an experimental method to determine the optimal range of temperature. In a second part the method to optimize the beam speed from the simulation results is presented. Finally, the optimized beam path is tested in the EBM machine and built part are compared with part built with ordinary beam path.

Nanobiotechnology-based strategies for crossing the blood-brain barrier.

PubMed

Jain, Kewal K

2012-08-01

The blood-brain barrier (BBB) is meant to protect the brain from noxious agents; however, it also significantly hinders the delivery of therapeutics to the brain. Several strategies have been employed to deliver drugs across this barrier and some of these may do structural damage to the BBB by forcibly opening it to allow the uncontrolled passage of drugs. The ideal method for transporting drugs across the BBB should be controlled and should not damage the barrier. Among the various approaches that are available, nanobiotechnology-based delivery methods provide the best prospects for achieving this ideal. This review describes various nanoparticle (NP)-based methods used for drug delivery to the brain and the known underlying mechanisms. Some strategies require multifunctional NPs combining controlled passage across the BBB with targeted delivery of the therapeutic cargo to the intended site of action in the brain. An important application of nanobiotechnology is to facilitate the delivery of drugs and biological therapeutics for brain tumors across the BBB. Although there are currently some limitations and concerns for the potential neurotoxicity of NPs, the future prospects for NP-based therapeutic delivery to the brain are excellent.

A Simple Microsoft Excel Method to Predict Antibiotic Outbreaks and Underutilization.

PubMed

Miglis, Cristina; Rhodes, Nathaniel J; Avedissian, Sean N; Zembower, Teresa R; Postelnick, Michael; Wunderink, Richard G; Sutton, Sarah H; Scheetz, Marc H

2017-07-01

Benchmarking strategies are needed to promote the appropriate use of antibiotics. We have adapted a simple regressive method in Microsoft Excel that is easily implementable and creates predictive indices. This method trends consumption over time and can identify periods of over- and underuse at the hospital level. Infect Control Hosp Epidemiol 2017;38:860-862.

Controlled laboratory challenge demonstrates substantial additive genetic variation in resistance to Streptococcus iniae in Nile tilapia

USDA-ARS?s Scientific Manuscript database

Streptococcus iniae is an etiologic agent of streptococcal disease in tilapia and is one of several Streptococcus spp. that negatively impact worldwide tilapia production. Methods for the prevention and control of S. iniae include vaccines, management strategies, and antibiotics. An alternative and ...

School Securitization and Latina/o Educational Progress

ERIC Educational Resources Information Center

Peguero, Anthony A.; Portillos, Edwardo L.; González, Juan Carlos

2015-01-01

Increasing control and security has become a common strategy to address school violence. Some argue, however, that increasing social control has detrimental consequences for racial and ethnic minorities, especially Latinas/os. This study utilizes mixed methods to research the influence of school justice, fairness, order, and discipline may have on…

Vector control programs in Saint Johns County, Florida and Guayas, Ecuador: successes and barriers to integrated vector management

PubMed Central

2014-01-01

Background Vector-borne diseases (VBDs) and mosquito control programs (MCPs) diverge in settings and countries, and lead control specialists need to be aware of the most effective control strategies. Integrated Vector Management (IVM) strategies, once implemented in MCPs, aim to reduce cost and optimize protection of the populations against VBDs. This study presents a strengths, weaknesses, opportunities, and threats (SWOT) analysis to compare IVM strategies used by MCPs in Saint Johns County, Florida and Guayas, Ecuador. This research evaluates MCPs strategies to improve vector control activities. Methods Methods included descriptive findings of the MCP operations. Information was obtained from vector control specialists, directors, and residents through field trips, surveys, and questionnaires. Evaluations of the strategies and assets of the control programs where obtained through SWOT analysis and within an IVM approach. Results Organizationally, the Floridian MCP is a tax-based District able to make decisions independently from county government officials, with the oversight of an elected board of commissioners. The Guayas program is directed by the country government and assessed by non-governmental organizations like the World health Organization. Operationally, the Floridian MCP conducts entomological surveillance and the Ecuadorian MCP focuses on epidemiological monitoring of human disease cases. Strengths of both MCPs were their community participation and educational programs. Weaknesses for both MCPs included limitations in budgets and technical capabilities. Opportunities, for both MCPs, are additional funding and partnerships with private, non-governmental, and governmental organizations. Threats experienced by both MCPs included political constraints and changes in the social and ecological environment that affect mosquito densities and control efforts. IVM pillars for policy making were used to compare the information among the programs. Differences included how the Ecuadorian MCP relies heavily on the community for vector control while the American MCP relies on technologies and research. Conclusion IVM based recommendations direct health policy leaders toward improving surveillance systems both entomologically and epidemiologically, improving community risk perceptions by integrating components of community participation, maximizing resources though the use of applied research, and protecting the environment by selecting low-risk pesticides. Outcomes of the research revealed that inter-sectorial and multidisciplinary interventions are critical to improve public health. PMID:24990155

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

NASA Astrophysics Data System (ADS)

Hua, Wei; Qi, Ji; Jia, Meng

2017-05-01

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

Delivering Faster Congestion Feedback with the Mark-Front Strategy

NASA Technical Reports Server (NTRS)

Liu, Chunlei; Jain, Raj

2001-01-01

Computer networks use congestion feedback from the routers and destinations to control the transmission load. Delivering timely congestion feedback is essential to the performance of networks. Reaction to the congestion can be more effective if faster feedback is provided. Current TCP/IP networks use timeout, duplicate Acknowledgement Packets (ACKs) and explicit congestion notification (ECN) to deliver the congestion feedback, each provides a faster feedback than the previous method. In this paper, we propose a markfront strategy that delivers an even faster congestion feedback. With analytical and simulation results, we show that mark-front strategy reduces buffer size requirement, improves link efficiency and provides better fairness among users. Keywords: Explicit Congestion Notification, mark-front, congestion control, buffer size requirement, fairness.

Expanding integrated vector management to promote healthy environments

PubMed Central

Lizzi, Karina M.; Qualls, Whitney A.; Brown, Scott C.; Beier, John C.

2014-01-01

Integrated Vector Management (IVM) strategies are intended to protect communities from pathogen transmission by arthropods. These strategies target multiple vectors and different ecological and socioeconomic settings, but the aggregate benefits of IVM are limited by the narrow focus of its approach; IVM strategies only aim to control arthropod vectors. We argue that IVM should encompass environmental modifications at early stages, for instance, infrastructural development and sanitation services, to regulate not only vectors but also nuisance-biting arthropods. An additional focus on nuisance-biting arthropods will improve public health, quality of life, and minimize social disparity issues fostered by pests. Optimally, IVM could incorporate environmental awareness and promotion of control methods in order to proactively reduce threats of serious pest situations. PMID:25028090

The active control strategy on the output power for photovoltaic-storage systems based on extended PQ-QV-PV Node

NASA Astrophysics Data System (ADS)

Xu, Chen; Zhou, Bao-Rong; Zhai, Jian-Wei; Zhang, Yong-Jun; Yi, Ying-Qi

2017-05-01

In order to solve the problem of voltage exceeding specified limits and improve the penetration of photovoltaic in distribution network, we can make full use of the active power regulation ability of energy storage(ES) and the reactive power regulation ability of grid-connected photovoltaic inverter to provide support of active power and reactive power for distribution network. A strategy of actively controlling the output power for photovoltaic-storage system based on extended PQ-QV-PV node by analyzing the voltage regulating mechanism of point of commom coupling(PCC) of photovoltaic with energy storage(PVES) by controlling photovoltaic inverter and energy storage. The strategy set a small wave range of voltage to every photovoltaic by making the type of PCC convert among PQ, PV and QV. The simulation results indicate that the active control method can provide a better solution to the problem of voltage exceeding specified limits when photovoltaic is connectted to electric distribution network.

A cross-sectional survey of experts’ opinions about the relative effectiveness of tobacco control strategies for the general population versus disadvantaged groups: what do we choose in the absence of evidence?

PubMed Central

2013-01-01

Background There is a clear disparity in smoking rates according to social disadvantage. In the absence of sufficiently robust data regarding effective strategies for reducing smoking prevalence in disadvantaged populations, understanding the views of tobacco control experts can assist with funding decisions and research agendas. Methods A web-based cross-sectional survey was conducted with 192 respondents (response rate 65%) sampled from the Australian and New Zealand Tobacco Control Contacts list and a literature search. Respondents were asked to indicate whether a number of tobacco control strategies were perceived to be effective for each of: the general population; Aboriginal and Torres Strait Islander people; those with a low income; and people with a mental illness. Results A high proportion of respondents indicated that mass media and increased tobacco taxation (84% and 89% respectively) were effective for the general population. Significantly lower proportions reported these two strategies were effective for sub-populations, particularly Aboriginal and Torres Strait Islanders (58% and 63% respectively, p’s < .0001). Subsidised medication was the only strategy associated with a greater proportion of respondents perceiving it to be effective in disadvantaged sub-populations compared to the general population. Tailored quit programs and culturally relevant programs were nominated as additional effective strategies for disadvantaged populations. Conclusions Views about subsidised medications in particular, suggest the need for robust cost-effectiveness data relevant to disadvantaged groups to avoid wastage of scarce tobacco control resources. Strategies perceived to be effective for disadvantaged populations such as tailored or culturally relevant programs require rigorous evaluation so that potential adoption of these approaches is evidence-based. PMID:24314097

Assessing Strategies Against Gambiense Sleeping Sickness Through Mathematical Modeling

PubMed Central

Rock, Kat S; Ndeffo-Mbah, Martial L; Castaño, Soledad; Palmer, Cody; Pandey, Abhishek; Atkins, Katherine E; Ndung’u, Joseph M; Hollingsworth, T Déirdre; Galvani, Alison; Bever, Caitlin; Chitnis, Nakul; Keeling, Matt J

2018-01-01

Abstract Background Control of gambiense sleeping sickness relies predominantly on passive and active screening of people, followed by treatment. Methods Mathematical modeling explores the potential of 3 complementary interventions in high- and low-transmission settings. Results Intervention strategies that included vector control are predicted to halt transmission most quickly. Targeted active screening, with better and more focused coverage, and enhanced passive surveillance, with improved access to diagnosis and treatment, are both estimated to avert many new infections but, when used alone, are unlikely to halt transmission before 2030 in high-risk settings. Conclusions There was general model consensus in the ranking of the 3 complementary interventions studied, although with discrepancies between the quantitative predictions due to differing epidemiological assumptions within the models. While these predictions provide generic insights into improving control, the most effective strategy in any situation depends on the specific epidemiology in the region and the associated costs. PMID:29860287

Promoting the Purchase of Low-Calorie Foods from School Vending Machines: A Cluster-Randomized Controlled Study

ERIC Educational Resources Information Center

Kocken, Paul L.; Eeuwijk, Jennifer; van Kesteren, Nicole M.C.; Dusseldorp, Elise; Buijs, Goof; Bassa-Dafesh, Zeina; Snel, Jeltje

2012-01-01

Background: Vending machines account for food sales and revenue in schools. We examined 3 strategies for promoting the sale of lower-calorie food products from vending machines in high schools in the Netherlands. Methods: A school-based randomized controlled trial was conducted in 13 experimental schools and 15 control schools. Three strategies…

Near-Optimal Tracking Control of Mobile Robots Via Receding-Horizon Dual Heuristic Programming.

PubMed

Lian, Chuanqiang; Xu, Xin; Chen, Hong; He, Haibo

2016-11-01

Trajectory tracking control of wheeled mobile robots (WMRs) has been an important research topic in control theory and robotics. Although various tracking control methods with stability have been developed for WMRs, it is still difficult to design optimal or near-optimal tracking controller under uncertainties and disturbances. In this paper, a near-optimal tracking control method is presented for WMRs based on receding-horizon dual heuristic programming (RHDHP). In the proposed method, a backstepping kinematic controller is designed to generate desired velocity profiles and the receding horizon strategy is used to decompose the infinite-horizon optimal control problem into a series of finite-horizon optimal control problems. In each horizon, a closed-loop tracking control policy is successively updated using a class of approximate dynamic programming algorithms called finite-horizon dual heuristic programming (DHP). The convergence property of the proposed method is analyzed and it is shown that the tracking control system based on RHDHP is asymptotically stable by using the Lyapunov approach. Simulation results on three tracking control problems demonstrate that the proposed method has improved control performance when compared with conventional model predictive control (MPC) and DHP. It is also illustrated that the proposed method has lower computational burden than conventional MPC, which is very beneficial for real-time tracking control.

Experimental implementation of acoustic impedance control by a 2D network of distributed smart cells

NASA Astrophysics Data System (ADS)

David, P.; Collet, M.; Cote, J.-M.

2010-03-01

New miniaturization and integration capabilities available from emerging microelectromechanical system (MEMS) technology will allow silicon-based artificial skins involving thousands of elementary actuators to be developed in the near future. Smart structures combining large arrays of elementary motion pixels are thus being studied so that fundamental properties could be dynamically adjusted. This paper investigates the acoustical capabilities of a network of distributed transducers connected with a suitable controlling strategy. The research aims at designing an integrated active interface for sound attenuation by using suitable changes of acoustical impedance. The control strategy is based on partial differential equations (PDE) and the multiscaled physics of electromechanical elements. Specific techniques based on PDE control theory have provided a simple boundary control equation able to annihilate the reflections of acoustic waves. To experimentally implement the method, the control strategy is discretized as a first order time-space operator. The obtained quasi-collocated architecture, composed of a large number of sensors and actuators, provides high robustness and stability. The experimental results demonstrate how a well controlled active skin can substantially modify sound reflectivity of the acoustical interface and reduce the propagation of acoustic waves.

Experimental Study of Flexible Plate Vibration Control by Using Two-Loop Sliding Mode Control Strategy

NASA Astrophysics Data System (ADS)

Yang, Jingyu; Lin, Jiahui; Liu, Yuejun; Yang, Kang; Zhou, Lanwei; Chen, Guoping

2017-08-01

It is well known that intelligent control theory has been used in many research fields, novel modeling method (DROMM) is used for flexible rectangular active vibration control, and then the validity of new model is confirmed by comparing finite element model with new model. In this paper, taking advantage of the dynamics of flexible rectangular plate, a two-loop sliding mode (TSM) MIMO approach is introduced for designing multiple-input multiple-output continuous vibration control system, which can overcome uncertainties, disturbances or unstable dynamics. An illustrative example is given in order to show the feasibility of the method. Numerical simulations and experiment confirm the effectiveness of the proposed TSM MIMO controller.

A modelling methodology to assess the effect of insect pest control on agro-ecosystems.

PubMed

Wan, Nian-Feng; Ji, Xiang-Yun; Jiang, Jie-Xian; Li, Bo

2015-04-23

The extensive use of chemical pesticides for pest management in agricultural systems can entail risks to the complex ecosystems consisting of economic, ecological and social subsystems. To analyze the negative and positive effects of external or internal disturbances on complex ecosystems, we proposed an ecological two-sidedness approach which has been applied to the design of pest-controlling strategies for pesticide pollution management. However, catastrophe theory has not been initially applied to this approach. Thus, we used an approach of integrating ecological two-sidedness with a multi-criterion evaluation method of catastrophe theory to analyze the complexity of agro-ecosystems disturbed by the insecticides and screen out the best insect pest-controlling strategy in cabbage production. The results showed that the order of the values of evaluation index (RCC/CP) for three strategies in cabbage production was "applying frequency vibration lamps and environment-friendly insecticides 8 times" (0.80) < "applying trap devices and environment-friendly insecticides 9 times" (0.83) < "applying common insecticides 14 times" (1.08). The treatment "applying frequency vibration lamps and environment-friendly insecticides 8 times" was considered as the best insect pest-controlling strategy in cabbage production in Shanghai, China.

A modelling methodology to assess the effect of insect pest control on agro-ecosystems

PubMed Central

Wan, Nian-Feng; Ji, Xiang-Yun; Jiang, Jie-Xian; Li, Bo

2015-01-01

The extensive use of chemical pesticides for pest management in agricultural systems can entail risks to the complex ecosystems consisting of economic, ecological and social subsystems. To analyze the negative and positive effects of external or internal disturbances on complex ecosystems, we proposed an ecological two-sidedness approach which has been applied to the design of pest-controlling strategies for pesticide pollution management. However, catastrophe theory has not been initially applied to this approach. Thus, we used an approach of integrating ecological two-sidedness with a multi-criterion evaluation method of catastrophe theory to analyze the complexity of agro-ecosystems disturbed by the insecticides and screen out the best insect pest-controlling strategy in cabbage production. The results showed that the order of the values of evaluation index (RCC/CP) for three strategies in cabbage production was “applying frequency vibration lamps and environment-friendly insecticides 8 times” (0.80) < “applying trap devices and environment-friendly insecticides 9 times” (0.83) < “applying common insecticides 14 times” (1.08). The treatment “applying frequency vibration lamps and environment-friendly insecticides 8 times” was considered as the best insect pest-controlling strategy in cabbage production in Shanghai, China. PMID:25906199

Integrated Pest Management of Coffee Berry Borer: Strategies from Latin America that Could Be Useful for Coffee Farmers in Hawaii

PubMed Central

Aristizábal, Luis F.; Bustillo, Alex E.; Arthurs, Steven P.

2016-01-01

The coffee berry borer (CBB), Hypothenemus hampei Ferrari (Coleoptera: Curculionidae: Scolytinae) is the primary arthropod pest of coffee plantations worldwide. Since its detection in Hawaii (September 2010), coffee growers are facing financial losses due to reduced quality of coffee yields. Several control strategies that include cultural practices, biological control agents (parasitoids), chemical and microbial insecticides (entomopathogenic fungi), and a range of post-harvest sanitation practices have been conducted to manage CBB around the world. In addition, sampling methods including the use of alcohol based traps for monitoring CBB populations have been implemented in some coffee producing countries in Latin America. It is currently unclear which combination of CBB control strategies is optimal under economical, environmental, and sociocultural conditions of Hawaii. This review discusses components of an integrated pest management program for CBB. We focus on practical approaches to provide guidance to coffee farmers in Hawaii. Experiences of integrated pest management (IPM) of CBB learned from Latin America over the past 25 years may be relevant for establishing strategies of control that may fit under Hawaiian coffee farmers’ conditions. PMID:26848690

A novel vehicle dynamics stability control algorithm based on the hierarchical strategy with constrain of nonlinear tyre forces

NASA Astrophysics Data System (ADS)

Li, Liang; Jia, Gang; Chen, Jie; Zhu, Hongjun; Cao, Dongpu; Song, Jian

2015-08-01

Direct yaw moment control (DYC), which differentially brakes the wheels to produce a yaw moment for the vehicle stability in a steering process, is an important part of electric stability control system. In this field, most control methods utilise the active brake pressure with a feedback controller to adjust the braked wheel. However, the method might lead to a control delay or overshoot because of the lack of a quantitative project relationship between target values from the upper stability controller to the lower pressure controller. Meanwhile, the stability controller usually ignores the implementing ability of the tyre forces, which might be restrained by the combined-slip dynamics of the tyre. Therefore, a novel control algorithm of DYC based on the hierarchical control strategy is brought forward in this paper. As for the upper controller, a correctional linear quadratic regulator, which not only contains feedback control but also contains feed forward control, is introduced to deduce the object of the stability yaw moment in order to guarantee the yaw rate and side-slip angle stability. As for the medium and lower controller, the quantitative relationship between the vehicle stability object and the target tyre forces of controlled wheels is proposed to achieve smooth control performance based on a combined-slip tyre model. The simulations with the hardware-in-the-loop platform validate that the proposed algorithm can improve the stability of the vehicle effectively.

Weight-control behaviors and subsequent weight change among adolescents and young adult females123

PubMed Central

Haines, Jess; Rosner, Bernard; Willett, Walter C

2010-01-01

Background: Little is known about the effectiveness of behavioral strategies to prevent long-term weight gain among adolescents and young adults. Objective: The objective was to assess the relation of dietary and physical activity weight-control strategies, alone and together, with subsequent weight change. Design: This was a prospective study of 4456 female adolescents and young adults aged 14–22 y in the ongoing Growing Up Today Study. Weight-control behaviors, including dietary approaches and physical activity, were self-reported in 2001 and were used to predict weight change from 2001 to 2005. Results: In 2001–2002, 23.7% of female adolescents and young adults were trying to maintain their weight and another 54.4% were trying to lose weight. Approximately 25% used each of the following weight-control strategies: not eating snacks, following low-calorie or low-fat diets, and limiting portion sizes. In addition, 47.7% reported exercising at least occasionally for weight control. During 4 y of follow-up, participants gained an average of 3.3 kg. None of the dietary approaches to weight control predicted less weight change; however, females who exercised ≥5 d/wk gained significantly less weight than did their peers (−0.9 kg; 95% CI: −1.4, −0.4). The most successful strategy for weight-gain prevention among the females was to limit portion sizes (−1.9 kg; 95% CI: −2.6, −1.1) combined with frequent exercise. Conclusions: Our results suggest that physical activity is a necessary strategy for long-term weight control among adolescents and young adult females. Combining dietary weight-control approaches with physical activity is the most effective method for reducing weight gain. PMID:19889827

Stabilization strategies of a general nonlinear car-following model with varying reaction-time delay of the drivers.

PubMed

Li, Shukai; Yang, Lixing; Gao, Ziyou; Li, Keping

2014-11-01

In this paper, the stabilization strategies of a general nonlinear car-following model with reaction-time delay of the drivers are investigated. The reaction-time delay of the driver is time varying and bounded. By using the Lyapunov stability theory, the sufficient condition for the existence of the state feedback control strategy for the stability of the car-following model is given in the form of linear matrix inequality, under which the traffic jam can be well suppressed with respect to the varying reaction-time delay. Moreover, by considering the external disturbance for the running cars, the robust state feedback control strategy is designed, which ensures robust stability and a smaller prescribed H∞ disturbance attenuation level for the traffic flow. Numerical examples are given to illustrate the effectiveness of the proposed methods. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

A systematic review on improving cognition in schizophrenia: which is the more commonly used type of training, practice or strategy learning?

PubMed Central

2014-01-01

Background The purpose of this article was to conduct a review of the types of training offered to people with schizophrenia in order to help them develop strategies to cope with or compensate for neurocognitive or sociocognitive deficits. Methods We conducted a search of the literature using keywords such as “schizophrenia”, “training”, and “cognition” with the most popular databases of peer-reviewed journals. Results We reviewed 99 controlled studies in total (though nine did not have a control condition). We found that drill and practice training is used more often to retrain neurocognitive deficits while drill and strategy training is used more frequently in the context of sociocognitive remediation. Conclusions Hypotheses are suggested to better understand those results and future research is recommended to compare drill and strategy with drill and practice training for both social and neurocognitive deficits in schizophrenia. PMID:24885300

Fully automatic control of paraplegic FES pedaling using higher-order sliding mode and fuzzy logic control.

PubMed

Farhoud, Aidin; Erfanian, Abbas

2014-05-01

In this paper, a fully automatic robust control strategy is proposed for control of paraplegic pedaling using functional electrical stimulation (FES). The method is based on higher-order sliding mode (HOSM) control and fuzzy logic control. In FES, the strength of muscle contraction can be altered either by varying the pulse width (PW) or by the pulse amplitude (PA) of the stimulation signal. The proposed control strategy regulates simultaneously both PA and PW (i.e., PA/PW modulation). A HOSM controller is designed for regulating the PW and a fuzzy logic controller for the PA. The proposed control scheme is free-model and does not require any offline training phase and subject-specific information. Simulation studies on a virtual patient and experiments on three paraplegic subjects demonstrate good tracking performance and robustness of the proposed control strategy against muscle fatigue and external disturbances during FES-induced pedaling. The results of simulation studies show that the power and cadence tracking errors are 5.4% and 4.8%, respectively. The experimental results indicate that the proposed controller can improve pedaling system efficacy and increase the endurance of FES pedaling. The average of power tracking error over three paraplegic subjects is 7.4±1.4% using PA/PW modulation, while the tracking error is 10.2±1.2% when PW modulation is used. The subjects could pedal for 15 min with about 4.1% power loss at the end of experiment using proposed control strategy, while the power loss is 14.3% using PW modulation. The controller could adjust the stimulation intensity to compensate the muscle fatigue during long period of FES pedaling.

Patient and Practice Perspectives on Strategies for Controlling Blood Pressure, North Carolina, 2010–2012

PubMed Central

Vu, Maihan B.; Halladay, Jacqueline R.; Miller, Cassandra; Garcia, Beverly A.; Cummings, Doyle M.; Cene, Crystal W.; Hinderliter, Alan; Little, Edwin; Rachide, Marjorie; DeWalt, Darren

2014-01-01

Introduction Patient and practice perspectives can inform development of team-based approaches to improving blood pressure control in primary care. We used a community-based participatory research approach to assess patient and practice perceptions regarding the value of team-based strategies for controlling blood pressure in a rural North Carolina population from 2010 through 2012. Methods In-depth interviews were conducted with 41 adults with hypertension, purposely sampled to include diversity of sex, race, literacy, and blood pressure control, and with key office staff at 5 rural primary care practices in the southeastern US “stroke belt.” Interviews explored barriers to controlling blood pressure, the practice’s role in controlling blood pressure, and opinions on the use of team care delivery. Results Patients reported that provider strategies to optimize blood pressure control should include regular visits, medication adjustment, side-effect discussion, and behavioral counseling. When discussing team-based approaches to hypertension care, patients valued verbal encouragement, calls from the doctor’s office, and the opportunity to ask questions. However, they voiced concerns about the effect of having too many people involved in their care. Practice staff focused on multiple, broad methods to control blood pressure including counseling, regular office visits, media to improve awareness, and support groups. An explicit focus of delivering care as teams was a newer concept. Conclusion When developing a team approach to hypertension treatment, patients value high-quality communication and not losing their primary relationship with their provider. Practice staff members were open to a team-based approach but had limited knowledge of what such an approach would entail. PMID:24762533

Comparative analysis of fabrication methods for achieving rounded microchannels in PDMS

NASA Astrophysics Data System (ADS)

Bartlett, Nicholas W.; Wood, Robert J.

2016-11-01

Many microfluidic applications demand control over channel cross-sectional geometry. In particular, rounded microchannels are essential to the function of microfluidic valves, which have played an integral part in the success of microfluidics over the past fifteen years. Here we investigate the relative strengths and weaknesses of different strategies for fabricating rounded microchannels in PDMS, systematically examining five common strategies. We consider the appropriateness of the fabrication strategies for microchannels of differing sizes and aspect ratios, and evaluate these various strategies on a number of metrics ranging from microchannel resolution to fabrication difficulty. We discuss the merits of the different strategies for a range of applications, and make recommendations on which strategy to use based on the driving constraints of the device.

Stance Postural Strategies in Patients with Chronic Inflammatory Demyelinating Polyradiculoneuropathy

PubMed Central

Missori, Paolo; Trompetto, Carlo; Fattapposta, Francesco

2016-01-01

Introduction Polyneuropathy leads to postural instability and an increased risk of falling. We investigated how impaired motor impairment and proprioceptive input due to neuropathy influences postural strategies. Methods Platformless bisegmental posturography data were recorded in healthy subjects and patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Each subject stood on the floor, wore a head and a hip electromagnetic tracker. Sway amplitude and velocity were recorded and the mean direction difference (MDD) in the velocity vector between trackers was calculated as a flexibility index. Results Head and hip postural sway increased more in patients with CIDP than in healthy controls. MDD values reflecting hip strategies also increased more in patients than in controls. In the eyes closed condition MDD values in healthy subjects decreased but in patients remained unchanged. Discussion Sensori-motor impairment changes the balance between postural strategies that patients adopt to maintain upright quiet stance. Motor impairment leads to hip postural strategy overweight (eyes open), and prevents strategy re-balancing when the sensory context predominantly relies on proprioceptive input (eyes closed). PMID:26977594

Investigation to identify a resource-efficient case-control methodology for determining antibiotics associated with Clostridium difficile infection.

PubMed

Chung, Philip; Currie, Brian; Guo, Yi; Talansky, Moshe; Brown, Shakara; Ostrowsky, Belinda

2014-10-01

Antimicrobial exposure remains an important risk factor for developing Clostridium difficile infection (CDI). Efficient method to identify antibiotics associated with CDI is important for formulating strategies to curtail their use. As a prelude to a more extensive Agency for Healthcare Research and Quality-funded project (Evaluation & Research on Antimicrobial Stewardship's Effect on Clostridium difficile), we undertook an exploratory evaluation to determine a resource-efficient method for identifying antibiotic targets for antimicrobial stewardship interventions. The study compared a series of 6 focused case-control studies. Cases consisted of patients with laboratory-confirmed CDI admitted from July-October 2009. Controls were selected from patients without CDI hospitalized during the same period. Five groups of controls were matched to cases (2:1 ratio) using group-specific matching criteria, including admission date, age, type of admission, length of stay (LOS) to discharge, and/or LOS to CDI diagnosis. The final control group was selected from patients who received antibiotics during hospitalization. Data, including demographics and antibiotic usage, were compared between case and control groups. A total of 126 cases were matched to 6 groups of 252 controls. For control groups 1-5, the use of piperacillin and tazobactam, ceftriaxone or cefepime, ciprofloxacin or moxifloxacin, intravenous vancomycin, azithromycin, and antibiotics of last resort were significantly more frequent in case than control patients. For the final control group, the associations between ceftriaxone or cefepime, and ciprofloxacin or moxifloxacin use and CDI no longer persisted. This could in part be explained by differences in comorbidities between case and control patients even with stringent matching criteria. Use of a simple matching strategy to conduct case-control studies is an efficient and feasible compromise strategy, especially in resource-limited settings, to identify high-risk antibiotics associated with CDI. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Coupled attitude-orbit dynamics and control for an electric sail in a heliocentric transfer mission.

PubMed

Huo, Mingying; Zhao, Jun; Xie, Shaobiao; Qi, Naiming

2015-01-01

The paper discusses the coupled attitude-orbit dynamics and control of an electric-sail-based spacecraft in a heliocentric transfer mission. The mathematical model characterizing the propulsive thrust is first described as a function of the orbital radius and the sail angle. Since the solar wind dynamic pressure acceleration is induced by the sail attitude, the orbital and attitude dynamics of electric sails are coupled, and are discussed together. Based on the coupled equations, the flight control is investigated, wherein the orbital control is studied in an optimal framework via a hybrid optimization method and the attitude controller is designed based on feedback linearization control. To verify the effectiveness of the proposed control strategy, a transfer problem from Earth to Mars is considered. The numerical results show that the proposed strategy can control the coupled system very well, and a small control torque can control both the attitude and orbit. The study in this paper will contribute to the theory study and application of electric sail.

Coupled Attitude-Orbit Dynamics and Control for an Electric Sail in a Heliocentric Transfer Mission

PubMed Central

Huo, Mingying; Zhao, Jun; Xie, Shaobiao; Qi, Naiming

2015-01-01

The paper discusses the coupled attitude-orbit dynamics and control of an electric-sail-based spacecraft in a heliocentric transfer mission. The mathematical model characterizing the propulsive thrust is first described as a function of the orbital radius and the sail angle. Since the solar wind dynamic pressure acceleration is induced by the sail attitude, the orbital and attitude dynamics of electric sails are coupled, and are discussed together. Based on the coupled equations, the flight control is investigated, wherein the orbital control is studied in an optimal framework via a hybrid optimization method and the attitude controller is designed based on feedback linearization control. To verify the effectiveness of the proposed control strategy, a transfer problem from Earth to Mars is considered. The numerical results show that the proposed strategy can control the coupled system very well, and a small control torque can control both the attitude and orbit. The study in this paper will contribute to the theory study and application of electric sail. PMID:25950179

Dynamic modeling of parallel robots for computed-torque control implementation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Codourey, A.

1998-12-01

In recent years, increased interest in parallel robots has been observed. Their control with modern theory, such as the computed-torque method, has, however, been restrained, essentially due to the difficulty in establishing a simple dynamic model that can be calculated in real time. In this paper, a simple method based on the virtual work principle is proposed for modeling parallel robots. The mass matrix of the robot, needed for decoupling control strategies, does not explicitly appear in the formulation; however, it can be computed separately, based on kinetic energy considerations. The method is applied to the DELTA parallel robot, leadingmore » to a very efficient model that has been implemented in a real-time computed-torque control algorithm.« less

Change in coping strategies following intensive intervention for special-service military personnel as civil emergency responders.

PubMed

Bian, Yongqiao; Xiong, Hongyan; Zhang, Lu; Tang, Tian; Liu, Zhen; Xu, Rufu; Lin, Hui; Xu, Bing

2011-01-01

To evaluate the effectiveness of a coping training program for the Chinese Special-Service Military Personnel (SSMP) as civil emergency responders. A parallel control trial was carried out in four special-service units (camps) stationed in Chongqing, China from Feb. 14th to May 30th, 2009. A total of 396 subjects were recruited and were randomly divided into an intervention group (n=201) and a control group (n=195) by clustering. Over the trial, participants in the intervention group received an additional coping-training program with 14 weekly two-hour sessions while the control group continued their normal work. Of all 396 participants, 343 attended all the sessions and completed the given measures. In comparison to their own scores in coping strategies at pre-intervention, significant and positive changes were observed in the intervention group (n=176) at post-intervention. Except for the strategy of self-blaming, the coping strategies including problem-solving, help-seeking, avoidance, fantasy and rationalization were improved. The descending order of the absolute change values over the trial in 5 coping strategies was fantasy, help-seeking, avoidance, problem-solving and rationalization. In addition, most subscales of social support and self-consistency, as powerful predictors of coping strategies, changed significantly over the intervention, while these changes were not observed in the control group (n=167). With the combined use of modular contents and procedural methods, our intervention not only led to fewer choices of immature coping strategies like fantasy, escape and rationalization, but also raised the use of mature coping strategies such as problem-solving and help-seeking. Accordingly, the intervention will be very helpful for regular coping training of Special-Service Units, something which can be verified and generalized for the whole SSMP in a future study.

Closed-loop and robust control of quantum systems.

PubMed

Chen, Chunlin; Wang, Lin-Cheng; Wang, Yuanlong

2013-01-01

For most practical quantum control systems, it is important and difficult to attain robustness and reliability due to unavoidable uncertainties in the system dynamics or models. Three kinds of typical approaches (e.g., closed-loop learning control, feedback control, and robust control) have been proved to be effective to solve these problems. This work presents a self-contained survey on the closed-loop and robust control of quantum systems, as well as a brief introduction to a selection of basic theories and methods in this research area, to provide interested readers with a general idea for further studies. In the area of closed-loop learning control of quantum systems, we survey and introduce such learning control methods as gradient-based methods, genetic algorithms (GA), and reinforcement learning (RL) methods from a unified point of view of exploring the quantum control landscapes. For the feedback control approach, the paper surveys three control strategies including Lyapunov control, measurement-based control, and coherent-feedback control. Then such topics in the field of quantum robust control as H(∞) control, sliding mode control, quantum risk-sensitive control, and quantum ensemble control are reviewed. The paper concludes with a perspective of future research directions that are likely to attract more attention.

RNA interference: a new strategy in the evolutionary arms race between human control strategies and insect pests.

PubMed

Machado, Vilmar; Rodríguez-García, María Juliana; Sánchez-García, Francisco Javier; Galan, Jose

2014-01-01

The relationship between humans and the insect pests of cultivated plants may be considered to be an indirect coevolutionary process, i.e., an arms race. Over time, humans have developed several strategies to minimize the negative impacts of insects on agricultural production. However, insects have made adaptive responses via the evolution of resistance to insecticides, and more recently against Bacillus thuriengiensis. Thus, we need to continuously invest resources in the development of new strategies for crop protection. Recent advances in genomics have demonstrated the possibility of a new weapon or strategy in this war, i.e., gene silencing, which involves blocking the expression of specific genes via mRNA inactivation. In the last decade, several studies have demonstrated the effectiveness of this strategy in the control of different species of insects. However, several technical difficulties need to be overcome to transform this potential into reality, such as the selection of target genes, the concentration of dsRNA, the nucleotide sequence of the dsRNA, the length of dsRNA, persistence in the insect body, and the life stage of the target species where gene silencing is most efficient. This study analyzes several aspects related to the use of gene silencing in pest control and it includes an overview of the inactivation process, as well as the problems that need to be resolved to transform gene silencing into an effective pest control method.

Light-inducible genetic engineering and control of non-homologous end-joining in industrial eukaryotic microorganisms: LML 3.0 and OFN 1.0

PubMed Central

Zhang, Lei; Zhao, Xihua; Zhang, Guoxiu; Zhang, Jiajia; Wang, Xuedong; Zhang, Suping; Wang, Wei; Wei, Dongzhi

2016-01-01

Filamentous fungi play important roles in the production of plant cell-wall degrading enzymes. In recent years, homologous recombinant technologies have contributed significantly to improved enzymes production and system design of genetically manipulated strains. When introducing multiple gene deletions, we need a robust and convenient way to control selectable marker genes, especially when only a limited number of markers are available in filamentous fungi. Integration after transformation is predominantly nonhomologous in most fungi other than yeast. Fungal strains deficient in the non-homologous end-joining (NHEJ) pathway have limitations associated with gene function analyses despite they are excellent recipient strains for gene targets. We describe strategies and methods to address these challenges above and leverage the power of resilient NHEJ deficiency strains. We have established a foolproof light-inducible platform for one-step unmarked genetic modification in industrial eukaryotic microorganisms designated as ‘LML 3.0’, and an on-off control protocol of NHEJ pathway called ‘OFN 1.0’, using a synthetic light-switchable transactivation to control Cre recombinase-based excision and inversion. The methods provide a one-step strategy to sequentially modify genes without introducing selectable markers and NHEJ-deficiency. The strategies can be used to manipulate many biological processes in a wide range of eukaryotic cells. PMID:26857594

Effectiveness of Using Flipped Classroom Strategy in Academic Achievement and Self-Efficacy among Education Students of Princess Nourah Bint Abdulrahman University

ERIC Educational Resources Information Center

AlJaser, Afaf Mohammed

2017-01-01

The present study is an attempt to measure the effectiveness of using flipped classroom strategy in academic achievement and self-efficacy among female students of College of Education, Princess Nourah bint Abdulrahman University (PNU), Saudi Arabia. The study adopted the experimental method based on the two experimental and control groups, where…

[Haptic tracking control for minimally invasive robotic surgery].

PubMed

Xu, Zhaohong; Song, Chengli; Wu, Wenwu

2012-06-01

Haptic feedback plays a significant role in minimally invasive robotic surgery (MIRS). A major deficiency of the current MIRS is the lack of haptic perception for the surgeon, including the commercially available robot da Vinci surgical system. In this paper, a dynamics model of a haptic robot is established based on Newton-Euler method. Because it took some period of time in exact dynamics solution, we used a digital PID arithmetic dependent on robot dynamics to ensure real-time bilateral control, and it could improve tracking precision and real-time control efficiency. To prove the proposed method, an experimental system in which two Novint Falcon haptic devices acting as master-slave system has been developed. Simulations and experiments showed proposed methods could give instrument force feedbacks to operator, and bilateral control strategy is an effective method to master-slave MIRS. The proposed methods could be used to tele-robotic system.

Data quality assurance and control in cognitive research: Lessons learned from the PREDICT-HD study.

PubMed

Westervelt, Holly James; Bernier, Rachel A; Faust, Melanie; Gover, Mary; Bockholt, H Jeremy; Zschiegner, Roland; Long, Jeffrey D; Paulsen, Jane S

2017-09-01

We discuss the strategies employed in data quality control and quality assurance for the cognitive core of Neurobiological Predictors of Huntington's Disease (PREDICT-HD), a long-term observational study of over 1,000 participants with prodromal Huntington disease. In particular, we provide details regarding the training and continual evaluation of cognitive examiners, methods for error corrections, and strategies to minimize errors in the data. We present five important lessons learned to help other researchers avoid certain assumptions that could potentially lead to inaccuracies in their cognitive data. Copyright © 2017 John Wiley & Sons, Ltd.

Operating wind turbines in strong wind conditions by using feedforward-feedback control

NASA Astrophysics Data System (ADS)

Feng, Ju; Sheng, Wen Zhong

2014-12-01

Due to the increasing penetration of wind energy into power systems, it becomes critical to reduce the impact of wind energy on the stability and reliability of the overall power system. In precedent works, Shen and his co-workers developed a re-designed operation schema to run wind turbines in strong wind conditions based on optimization method and standard PI feedback control, which can prevent the typical shutdowns of wind turbines when reaching the cut-out wind speed. In this paper, a new control strategy combing the standard PI feedback control with feedforward controls using the optimization results is investigated for the operation of variable-speed pitch-regulated wind turbines in strong wind conditions. It is shown that the developed control strategy is capable of smoothening the power output of wind turbine and avoiding its sudden showdown at high wind speeds without worsening the loads on rotor and blades.

Application of fuzzy adaptive control to a MIMO nonlinear time-delay pump-valve system.

PubMed

Lai, Zhounian; Wu, Peng; Wu, Dazhuan

2015-07-01

In this paper, a control strategy to balance the reliability against efficiency is introduced to overcome the common off-design operation problem in pump-valve systems. The pump-valve system is a nonlinear multi-input-multi-output (MIMO) system with time delays which cannot be accurately measured but can be approximately modeled using Bernoulli Principle. A fuzzy adaptive controller is applied to approximate system parameters and achieve the control of delay-free model since the system model is inaccurate and the direct feedback linearization method cannot be applied. An extended Smith predictor is introduced to compensate time delays of the system using the inaccurate system model. The experiment is carried out to verify the effectiveness of the control strategy whose results show that the control performance is well achieved. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Strategies for Managing Nursing Students’ Incivility as Experienced by Nursing Educators: a Qualitative Study

PubMed Central

Rad, Mostafa; Karimi Moonaghi, Hossein

2016-01-01

Introduction: Students’ incivility is an impolite and disturbing behavior in education and if ignored could lead to behavioral complexities and eventually violence and aggression in classrooms. This study aimed to reveal the experiences of Iranian educators regarding the management of such behaviors. Methods: In this qualitative study, qualitative content analysis method was used to evaluate the experiences and perceptions of nursing educators and students. A total of 22 persons (14 educators and 8 students) were selected through purposive sampling and individually interviewed. Results: Categories of unification of educators regarding behavioral management, teaching-learning strategy, friendship strategy and training through role playing, authority, appropriative decision-making and freedom, stronger relationships between students, reflection, and interactive educational environment were some strategies used by teachers for management of incivility. Conclusion: Educators suggested some strategies which could be used depending on uniqueness of behaviors and given situation. Educators and managers of medical fields can use these approaches in their classrooms to control uncivil behaviors. PMID:26989663

Lawn and Garden

EPA Pesticide Factsheets

The most effective strategy for controlling pests in your lawn and garden may be to combine methods in an approach known as Integrated Pest Management. See videos and find tips for implementing IPM at your residence.

Real time control of a combined sewer system using radar-measured precipitation--results of the pilot study.

PubMed

Petruck, A; Holtmeier, E; Redder, A; Teichgräber, B

2003-01-01

Emschergenossenschaft and Lippeverband have developed a method to use radar-measured precipitation as an input for a real-time control of a combined sewer system containing several overflow structures. Two real-time control strategies have been developed and tested, one is solely volume-based, the other is volume and pollution-based. The system has been implemented in a pilot study in Gelsenkirchen, Germany. During the project the system was optimised and is now in constant operation. It was found, that the volume of combined sewage overflow could be reduced by 5 per cent per year. This was also found in simulations carried out in similar catchment areas. Most of the potential of improvement can already be achieved by local pollution-based control strategies.

Controlled challenge experiment demonstrates substantial additive genetic variation in resistance of Nile tilapia (Oreochromis niloticus) to Streptococcus iniae

USDA-ARS?s Scientific Manuscript database

Streptococcus iniae is an etiologic agent of streptococcal disease in tilapia and is one of several Streptococcus spp. that negatively impact worldwide tilapia production. Methods for the prevention and control of S. iniae include vaccines, management strategies, and antibiotics. A complimentary pre...

Diagnosis before treatment: Identifying dairy farmers' determinants for the adoption of sustainable practices in gastrointestinal nematode control.

PubMed

Vande Velde, F; Claerebout, E; Cauberghe, V; Hudders, L; Van Loo, H; Vercruysse, J; Charlier, J

2015-09-15

Anthelmintic resistance is emerging in dairy cattle and this can result in a lack of effective control and production losses. Therefore, sustainable control strategies, such as targeted treatments (TT) and targeted selected treatments (TST), should be adopted by the industry. TT and TST approaches require the use of diagnostic methods to take informed treatment decisions. To understand the factors affecting the farmers' intention to adopt diagnostic methods before implementing anthelmintic drugs ('adoption intention'), a cross-sectional survey was carried out in dairy farms in Belgium (Flanders). A framework was constructed to predict adoption intentions based on two fundamental theories in the field of behavioural psychology and health psychology: the Theory of Planned Behaviour and the Health Belief Model. In the tested model, adoption intentions were predicted based on attitudes towards anthelminthics, attitudes towards diagnostic methods, subjective norms, behavioural control and perceived risk. Structural equation modelling was used for analyses. The model fitted the data well and explained 46% of the variance in adoption intention of diagnostics. The factors 'attitude towards diagnostic methods' and 'subjective norm'; i.e. the influence of significant others, had the strongest, positive influence on adoption intention of diagnostic methods. 'Perceived behavioural control' had a weak, positive effect on intention. Further, 'attitude towards the use of anthelmintic drugs' had a negative effect on adoption intention of the diagnostic methods. This implicates an effect of current behaviour on future adoption, which should be considered in future research. Factors measuring risk perception of anthelmintic resistance; perceived severity and perceived susceptibility, had no effect on the adoption intention of diagnostic methods. The threat of anthelmintic resistance is perceived to be low for dairy herds. The study further did not find any differences in the effects of the predictors for young stock and adult dairy cows. The results of this study can be used to develop communication strategies to advertise sustainable nematode control on dairy farms. Copyright © 2015 Elsevier B.V. All rights reserved.

Data analytics and optimization of an ice-based energy storage system for commercial buildings

DOE PAGES

Luo, Na; Hong, Tianzhen; Li, Hui; ...

2017-07-25

Ice-based thermal energy storage (TES) systems can shift peak cooling demand and reduce operational energy costs (with time-of-use rates) in commercial buildings. The accurate prediction of the cooling load, and the optimal control strategy for managing the charging and discharging of a TES system, are two critical elements to improving system performance and achieving energy cost savings. This study utilizes data-driven analytics and modeling to holistically understand the operation of an ice–based TES system in a shopping mall, calculating the system’s performance using actual measured data from installed meters and sensors. Results show that there is significant savings potential whenmore » the current operating strategy is improved by appropriately scheduling the operation of each piece of equipment of the TES system, as well as by determining the amount of charging and discharging for each day. A novel optimal control strategy, determined by an optimization algorithm of Sequential Quadratic Programming, was developed to minimize the TES system’s operating costs. Three heuristic strategies were also investigated for comparison with our proposed strategy, and the results demonstrate the superiority of our method to the heuristic strategies in terms of total energy cost savings. Specifically, the optimal strategy yields energy costs of up to 11.3% per day and 9.3% per month compared with current operational strategies. A one-day-ahead hourly load prediction was also developed using machine learning algorithms, which facilitates the adoption of the developed data analytics and optimization of the control strategy in a real TES system operation.« less

Data analytics and optimization of an ice-based energy storage system for commercial buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luo, Na; Hong, Tianzhen; Li, Hui

Ice-based thermal energy storage (TES) systems can shift peak cooling demand and reduce operational energy costs (with time-of-use rates) in commercial buildings. The accurate prediction of the cooling load, and the optimal control strategy for managing the charging and discharging of a TES system, are two critical elements to improving system performance and achieving energy cost savings. This study utilizes data-driven analytics and modeling to holistically understand the operation of an ice–based TES system in a shopping mall, calculating the system’s performance using actual measured data from installed meters and sensors. Results show that there is significant savings potential whenmore » the current operating strategy is improved by appropriately scheduling the operation of each piece of equipment of the TES system, as well as by determining the amount of charging and discharging for each day. A novel optimal control strategy, determined by an optimization algorithm of Sequential Quadratic Programming, was developed to minimize the TES system’s operating costs. Three heuristic strategies were also investigated for comparison with our proposed strategy, and the results demonstrate the superiority of our method to the heuristic strategies in terms of total energy cost savings. Specifically, the optimal strategy yields energy costs of up to 11.3% per day and 9.3% per month compared with current operational strategies. A one-day-ahead hourly load prediction was also developed using machine learning algorithms, which facilitates the adoption of the developed data analytics and optimization of the control strategy in a real TES system operation.« less

Visual analytics of geo-social interaction patterns for epidemic control.

PubMed

Luo, Wei

2016-08-10

Human interaction and population mobility determine the spatio-temporal course of the spread of an airborne disease. This research views such spreads as geo-social interaction problems, because population mobility connects different groups of people over geographical locations via which the viruses transmit. Previous research argued that geo-social interaction patterns identified from population movement data can provide great potential in designing effective pandemic mitigation. However, little work has been done to examine the effectiveness of designing control strategies taking into account geo-social interaction patterns. To address this gap, this research proposes a new framework for effective disease control; specifically this framework proposes that disease control strategies should start from identifying geo-social interaction patterns, designing effective control measures accordingly, and evaluating the efficacy of different control measures. This framework is used to structure design of a new visual analytic tool that consists of three components: a reorderable matrix for geo-social mixing patterns, agent-based epidemic models, and combined visualization methods. With real world human interaction data in a French primary school as a proof of concept, this research compares the efficacy of vaccination strategies between the spatial-social interaction patterns and the whole areas. The simulation results show that locally targeted vaccination has the potential to keep infection to a small number and prevent spread to other regions. At some small probability, the local control strategies will fail; in these cases other control strategies will be needed. This research further explores the impact of varying spatial-social scales on the success of local vaccination strategies. The results show that a proper spatial-social scale can help achieve the best control efficacy with a limited number of vaccines. The case study shows how GS-EpiViz does support the design and testing of advanced control scenarios in airborne disease (e.g., influenza). The geo-social patterns identified through exploring human interaction data can help target critical individuals, locations, and clusters of locations for disease control purposes. The varying spatial-social scales can help geographically and socially prioritize limited resources (e.g., vaccines).

Synchronization of coupled stochastic complex-valued dynamical networks with time-varying delays via aperiodically intermittent adaptive control

NASA Astrophysics Data System (ADS)

Wang, Pengfei; Jin, Wei; Su, Huan

2018-04-01

This paper deals with the synchronization problem of a class of coupled stochastic complex-valued drive-response networks with time-varying delays via aperiodically intermittent adaptive control. Different from the previous works, the intermittent control is aperiodic and adaptive, and the restrictions on the control width and time delay are removed, which lead to a larger application scope for this control strategy. Then, based on the Lyapunov method and Kirchhoff's Matrix Tree Theorem as well as differential inequality techniques, several novel synchronization conditions are derived for the considered model. Specially, impulsive control is also considered, which can be seen as a special case of the aperiodically intermittent control when the control width tends to zero. And the corresponding synchronization criteria are given as well. As an application of the theoretical results, a class of stochastic complex-valued coupled oscillators with time-varying delays is studied, and the numerical simulations are also given to demonstrate the effectiveness of the control strategies.

Systematic review of management strategies to control chronic wasting disease in wild deer populations in North America.

PubMed

Uehlinger, F D; Johnston, A C; Bollinger, T K; Waldner, C L

2016-08-22

Chronic wasting disease (CWD) is a contagious, fatal prion disease affecting cervids in a growing number of regions across North America. Projected deer population declines and concern about potential spread of CWD to other species warrant strategies to manage this disease. Control efforts to date have been largely unsuccessful, resulting in continuing spread and increasing prevalence. This systematic review summarizes peer-reviewed published reports describing field-applicable CWD control strategies in wild deer populations in North America using systematic review methods. Ten databases were searched for peer-reviewed literature. Following deduplication, relevance screening, full-text appraisal, subject matter expert review and qualitative data extraction, nine references were included describing four distinct management strategies. Six of the nine studies used predictive modeling to evaluate control strategies. All six demonstrated one or more interventions to be effective but results were dependant on parameters and assumptions used in the model. Three found preferential removal of CWD infected deer to be effective in reducing CWD prevalence; one model evaluated a test and slaughter strategy, the other selective removal of infected deer by predators and the third evaluated increased harvest of the sex with highest prevalence (males). Three models evaluated non-selective harvest of deer. There were only three reports that examined primary data collected as part of observational studies. Two of these studies supported the effectiveness of intensive non-selective culling; the third study did not find a difference between areas that were subjected to culling and those that were not. Seven of the nine studies were conducted in the United States. This review highlights the paucity of evaluated, field-applicable control strategies for CWD in wild deer populations. Knowledge gaps in the complex epidemiology of CWD and the intricacies inherent to prion diseases currently pose significant challenges to effective control of this disease in wild deer in North America.

Development of tools to study personal weight control strategies: OxFAB taxonomy

PubMed Central

Aveyard, Paul; Koshiaris, Constantinos; Jebb, Susan A.

2016-01-01

Objective To describe the development of the Oxford Food and Activity Behaviors (OxFAB) taxonomy and questionnaire to explore the cognitive and behavioral strategies used by individuals during weight management attempts. Methods The taxonomy was constructed through a qualitative analysis of existing resources and a review of existing behavior change taxonomies and theories. The taxonomy was translated into a questionnaire to identify strategies used by individuals. Think‐aloud interviews were conducted to test the face/concept validity of the questionnaire, and test–retest reliability was assessed in a sample of 138 participants. Results The OxFAB taxonomy consists of 117 strategies grouped into 23 domains. Compared to taxonomies used to describe interventions, around half of the domains and strategies identified are unique to the OxFAB taxonomy. The OxFAB questionnaire consists of 117 questions, one for each strategy from the taxonomy. Test–retest resulted in a mean PABAK score of 0.61 (SD 0.15). Questions were revised where appropriate. Conclusions The OxFAB taxonomy and questionnaire provide a conceptual framework to identify the cognitive and behavioral strategies used by individuals during attempts at weight control. PMID:26748902

Protecting the brain during neurosurgical procedures: strategies that can work.

PubMed

El Beheiry, Hossam

2012-10-01

The quest for neuroprotection strategies during periods of neuronal vulnerability persists despite decades of basic and clinical research. This review will focus on the latest developments in the area of clinical brain protection with the major emphasis on strategies that can be beneficial during neurosurgical procedures. Brain protection in neurosurgical patients may be achieved by nonpharmacological and pharmacological strategies. Pharmacological neuroprotection including anaesthetic administration have not been recently shown to be successful. Alternatively, nonpharmacological strategies including maintenance of cerebral perfusion by adequate control of mean arterial pressure (≥80 mmHg), liberal normoglycaemia (7.8-10 mmol/l), adequate haemoglobin levels (preoperative ≥120 g/l and intraoperative ≥90 g/l) and induction of hypertension (20-40% of preoperative values) in certain neurosurgical situations can be beneficial as neuroprotectants during neurosurgery. Mild hypothermia (32-35°C) failed to achieve neuroprotective effects in several situations of brain injury. The findings of this review suggest that the anaesthesiologist is compelled to use nonpharmacological strategies sometimes based on empiric evidence to protect the brain during neurosurgical procedures. These strategies are simple, have high benefit/risk ratios and are inexpensive. Rigorous controlled clinical studies are needed to investigate the neuroprotective efficacy of these commonly used nonpharmacological methods.

Adopting an Evidence-Based Lifestyle Physical Activity Program: Dissemination Study Design and Methods.

PubMed

Dunn, Andrea L; Buller, David B; Dearing, James W; Cutter, Gary; Guerra, Michele; Wilcox, Sara; Bettinghaus, Erwin P

2012-06-01

BACKGROUND: There is a scarcity of research studies that have examined academic-commercial partnerships to disseminate evidence-based physical activity programs. Understanding this approach to dissemination is essential because academic-commercial partnerships are increasingly common. Private companies have used dissemination channels and strategies to a degree that academicians have not, and declining resources require academicians to explore these partnerships. PURPOSE: This paper describes a retrospective case-control study design including the methods, demographics, organizational decision-making, implementation rates, and marketing strategy for Active Living Every Day (ALED), an evidence-based lifestyle physical activity program that has been commercially available since 2001. Evidence-based public health promotion programs rely on organizations and targeted sectors to disseminate these programs although relatively little is known about organizational-level and sector-level influences that lead to their adoption and implementation. METHODS: Cases (n=154) were eligible if they had signed an ALED license agreement with Human Kinetics (HK), publisher of the program's textbooks and facilitator manuals, between 2001 and 2008. Two types of controls were matched (2:2:1) and stratified by sector and region. Active controls (Control 1; n=319) were organizations that contacted HK to consider adopting ALED. Passive controls (Control 2; n=328) were organizations that received unsolicited marketing materials and did not initiate contact with HK. We used Diffusion of Innovations Theory (DIT) constructs as the basis for developing the survey of cases and controls. RESULTS: Using the multi-method strategy recommended by Dillman, a total of n=801 cases and controls were surveyed. Most organizations were from the fitness sector followed by medical, nongovernmental, governmental, educational, worksite and other sectors with significantly higher response rates from government, educational and medical sectors compared with fitness and other sectors, (p=0.02). More cases reported being involved in the decision to adopt ALED (p<0.0001). Data indicate that a low percentage of controls had ever heard of ALED despite repeated marketing and offering other types of physical activity programs and services. Finally, slightly over half of the adopters reported they had actually implemented the ALED program. CONCLUSION: Dissemination research requires new perspectives and designs to produce valid insights about the results of dissemination efforts. This study design, survey methods and theoretically-based questions can serve as a useful model for other evidence-based public health interventions that are marketed by commercial publishers to better understand key issues related to adoption and implementation of evidence-based programs.

Preventing malaria in the Peruvian Amazon: a qualitative study in Iquitos, Peru.

PubMed

Newell, Ian; Wiskin, Connie; Anthoney, James; Meza, Graciela; de Wildt, Gilles

2018-01-16

In Peru, despite decades of concerted control efforts, malaria remains a significant public health burden. Peru has recently exhibited a dramatic rise in malaria incidence, impeding South America's progress towards malaria elimination. The Amazon basin, in particular the Loreto region of Peru, has been identified as a target for the implementation of intensified control strategies, aiming for elimination. No research has addressed why vector control strategies in Loreto have had limited impact in the past, despite vector control elsewhere being highly effective in reducing malaria transmission. This study employed qualitative methods to explore factors limiting the success of vector control strategies in the region. Twenty semi-structured interviews were conducted among adults attending a primary care centre in Iquitos, Peru, together with 3 interviews with key informants (health care professionals). The interviews focussed on how local knowledge, together with social and cultural attitudes, determined the use of vector control methods. Five themes emerged. (a) Participants believed malaria to be embedded within their culture, and commonly blamed this for a lack of regard for prevention. (b) They perceived a shift in mosquito biting times to early evening, rendering night-time use of bed nets less effective. (c) Poor preventive practices were compounded by a consensus that malaria prevention was the government's responsibility, and that this reduced motivation for personal prevention. (d) Participants confused the purpose of space-spraying. (e) Participants' responses also exposed persisting misconceptions, mainly concerning the cause of malaria and best practices for its prevention. To eliminate malaria from the Americas, region-specific strategies need to be developed that take into account the local social and cultural contexts. In Loreto, further research is needed to explore the potential shift in biting behaviour of Anopheles darlingi, and how this interacts with the population's social behaviours and current use of preventive measures. Attitudes concerning personal responsibility for malaria prevention and long-standing misconceptions as to the cause of malaria and best preventive practices also need to be addressed.

The influence of parametric and external noise in act-and-wait control with delayed feedback.

PubMed

Wang, Jiaxing; Kuske, Rachel

2017-11-01

We apply several novel semi-analytic approaches for characterizing and calculating the effects of noise in a system with act-and-wait control. For concrete illustration, we apply these to a canonical balance model for an inverted pendulum to study the combined effect of delay and noise within the act-and-wait setting. While the act-and-wait control facilitates strong stabilization through deadbeat control, a comparison of different models with continuous vs. discrete updating of the control strategy in the active period illustrates how delays combined with the imprecise application of the control can seriously degrade the performance. We give several novel analyses of a generalized act-and-wait control strategy, allowing flexibility in the updating of the control strategy, in order to understand the sensitivities to delays and random fluctuations. In both the deterministic and stochastic settings, we give analytical and semi-analytical results that characterize and quantify the dynamics of the system. These results include the size and shape of stability regions, densities for the critical eigenvalues that capture the rate of reaching the desired stable equilibrium, and amplification factors for sustained fluctuations in the context of external noise. They also provide the dependence of these quantities on the length of the delay and the active period. In particular, we see that the combined influence of delay, parametric error, or external noise and on-off control can qualitatively change the dynamics, thus reducing the robustness of the control strategy. We also capture the dependence on how frequently the control is updated, allowing an interpolation between continuous and frequent updating. In addition to providing insights for these specific models, the methods we propose are generalizable to other settings with noise, delay, and on-off control, where analytical techniques are otherwise severely scarce.

Parasite control in the age of drug resistance and changing agricultural practices.

PubMed

Molento, Marcelo Beltrão

2009-08-07

The benefits of using antiparasitic drugs in farm animals are unquestionable. However, despite anthelmintic use as the predominant control strategy, extreme parasite infection cases are appearing in sheep and goat production; these impact productivity and have show mortality rates reaching pre-drug use levels. This was a predictable situation resulting from the loss of efficacy by all available products, particularly when some products were used as the sole intervention. The concepts of agroecology and holistic agriculture, which advocate the use of integrated management strategies, such as target selected treatment, herbal medicine, and the application of other parasite control alternatives, are not completely new, but are undergoing a resurgence because of their more sustainable appeal. The objective of this review article is to examine the problem of parasite control in the face of parasite drug resistance and to outline some strategies that may be used in parasite control programmes. Before they are accepted and recommended by the WAAVP, agroecological methods such as those listed above and described in detail herein should be validated based on scientific evidence of their efficacy for parasite control and should be tested for both host and environmental safety.

A simple multi-scale Gaussian smoothing-based strategy for automatic chromatographic peak extraction.

PubMed

Fu, Hai-Yan; Guo, Jun-Wei; Yu, Yong-Jie; Li, He-Dong; Cui, Hua-Peng; Liu, Ping-Ping; Wang, Bing; Wang, Sheng; Lu, Peng

2016-06-24

Peak detection is a critical step in chromatographic data analysis. In the present work, we developed a multi-scale Gaussian smoothing-based strategy for accurate peak extraction. The strategy consisted of three stages: background drift correction, peak detection, and peak filtration. Background drift correction was implemented using a moving window strategy. The new peak detection method is a variant of the system used by the well-known MassSpecWavelet, i.e., chromatographic peaks are found at local maximum values under various smoothing window scales. Therefore, peaks can be detected through the ridge lines of maximum values under these window scales, and signals that are monotonously increased/decreased around the peak position could be treated as part of the peak. Instrumental noise was estimated after peak elimination, and a peak filtration strategy was performed to remove peaks with signal-to-noise ratios smaller than 3. The performance of our method was evaluated using two complex datasets. These datasets include essential oil samples for quality control obtained from gas chromatography and tobacco plant samples for metabolic profiling analysis obtained from gas chromatography coupled with mass spectrometry. Results confirmed the reasonability of the developed method. Copyright © 2016 Elsevier B.V. All rights reserved.

Missing value imputation strategies for metabolomics data.

PubMed

Armitage, Emily Grace; Godzien, Joanna; Alonso-Herranz, Vanesa; López-Gonzálvez, Ángeles; Barbas, Coral

2015-12-01

The origin of missing values can be caused by different reasons and depending on these origins missing values should be considered differently and dealt with in different ways. In this research, four methods of imputation have been compared with respect to revealing their effects on the normality and variance of data, on statistical significance and on the approximation of a suitable threshold to accept missing data as truly missing. Additionally, the effects of different strategies for controlling familywise error rate or false discovery and how they work with the different strategies for missing value imputation have been evaluated. Missing values were found to affect normality and variance of data and k-means nearest neighbour imputation was the best method tested for restoring this. Bonferroni correction was the best method for maximizing true positives and minimizing false positives and it was observed that as low as 40% missing data could be truly missing. The range between 40 and 70% missing values was defined as a "gray area" and therefore a strategy has been proposed that provides a balance between the optimal imputation strategy that was k-means nearest neighbor and the best approximation of positioning real zeros. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

TU-AB-BRC-11: Moving a GPU-OpenCL-Based Monte Carlo (MC) Dose Engine Towards Routine Clinical Use: Automatic Beam Commissioning and Efficient Source Sampling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tian, Z; Folkerts, M; Jiang, S

Purpose: We have previously developed a GPU-OpenCL-based MC dose engine named goMC with built-in analytical linac beam model. To move goMC towards routine clinical use, we have developed an automatic beam-commissioning method, and an efficient source sampling strategy to facilitate dose calculations for real treatment plans. Methods: Our commissioning method is to automatically adjust the relative weights among the sub-sources, through an optimization process minimizing the discrepancies between calculated dose and measurements. Six models built for Varian Truebeam linac photon beams (6MV, 10MV, 15MV, 18MV, 6MVFFF, 10MVFFF) were commissioned using measurement data acquired at our institution. To facilitate dose calculationsmore » for real treatment plans, we employed inverse sampling method to efficiently incorporate MLC leaf-sequencing into source sampling. Specifically, instead of sampling source particles control-point by control-point and rejecting the particles blocked by MLC, we assigned a control-point index to each sampled source particle, according to MLC leaf-open duration of each control-point at the pixel where the particle intersects the iso-center plane. Results: Our auto-commissioning method decreased distance-to-agreement (DTA) of depth dose at build-up regions by 36.2% averagely, making it within 1mm. Lateral profiles were better matched for all beams, with biggest improvement found at 15MV for which root-mean-square difference was reduced from 1.44% to 0.50%. Maximum differences of output factors were reduced to less than 0.7% for all beams, with largest decrease being from1.70% to 0.37% found at 10FFF. Our new sampling strategy was tested on a Head&Neck VMAT patient case. Achieving clinically acceptable accuracy, the new strategy could reduce the required history number by a factor of ∼2.8 given a statistical uncertainty level and hence achieve a similar speed-up factor. Conclusion: Our studies have demonstrated the feasibility and effectiveness of our auto-commissioning approach and new efficient source sampling strategy, implying the potential of our GPU-based MC dose engine goMC for routine clinical use.« less

Software development environments: Status and trends

NASA Technical Reports Server (NTRS)

Duffel, Larry E.

1988-01-01

Currently software engineers are the essential integrating factors tying several components together. The components consist of process, methods, computers, tools, support environments, and software engineers. The engineers today empower the tools versus the tools empowering the engineers. Some of the issues in software engineering are quality, managing the software engineering process, and productivity. A strategy to accomplish this is to promote the evolution of software engineering from an ad hoc, labor intensive activity to a managed, technology supported discipline. This strategy may be implemented by putting the process under management control, adopting appropriate methods, inserting the technology that provides automated support for the process and methods, collecting automated tools into an integrated environment and educating the personnel.

Control of a 2 DoF robot using a brain-machine interface.

PubMed

Hortal, Enrique; Ubeda, Andrés; Iáñez, Eduardo; Azorín, José M

2014-09-01

In this paper, a non-invasive spontaneous Brain-Machine Interface (BMI) is used to control the movement of a planar robot. To that end, two mental tasks are used to manage the visual interface that controls the robot. The robot used is a PupArm, a force-controlled planar robot designed by the nBio research group at the Miguel Hernández University of Elche (Spain). Two control strategies are compared: hierarchical and directional control. The experimental test (performed by four users) consists of reaching four targets. The errors and time used during the performance of the tests are compared in both control strategies (hierarchical and directional control). The advantages and disadvantages of each method are shown after the analysis of the results. The hierarchical control allows an accurate approaching to the goals but it is slower than using the directional control which, on the contrary, is less precise. The results show both strategies are useful to control this planar robot. In the future, by adding an extra device like a gripper, this BMI could be used in assistive applications such as grasping daily objects in a realistic environment. In order to compare the behavior of the system taking into account the opinion of the users, a NASA Tasks Load Index (TLX) questionnaire is filled out after two sessions are completed. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Reentry trajectory optimization based on a multistage pseudospectral method.

PubMed

Zhao, Jiang; Zhou, Rui; Jin, Xuelian

2014-01-01

Of the many direct numerical methods, the pseudospectral method serves as an effective tool to solve the reentry trajectory optimization for hypersonic vehicles. However, the traditional pseudospectral method is time-consuming due to large number of discretization points. For the purpose of autonomous and adaptive reentry guidance, the research herein presents a multistage trajectory control strategy based on the pseudospectral method, capable of dealing with the unexpected situations in reentry flight. The strategy typically includes two subproblems: the trajectory estimation and trajectory refining. In each processing stage, the proposed method generates a specified range of trajectory with the transition of the flight state. The full glide trajectory consists of several optimal trajectory sequences. The newly focused geographic constraints in actual flight are discussed thereafter. Numerical examples of free-space flight, target transition flight, and threat avoidance flight are used to show the feasible application of multistage pseudospectral method in reentry trajectory optimization.

Reentry Trajectory Optimization Based on a Multistage Pseudospectral Method

PubMed Central

Zhou, Rui; Jin, Xuelian

2014-01-01

Of the many direct numerical methods, the pseudospectral method serves as an effective tool to solve the reentry trajectory optimization for hypersonic vehicles. However, the traditional pseudospectral method is time-consuming due to large number of discretization points. For the purpose of autonomous and adaptive reentry guidance, the research herein presents a multistage trajectory control strategy based on the pseudospectral method, capable of dealing with the unexpected situations in reentry flight. The strategy typically includes two subproblems: the trajectory estimation and trajectory refining. In each processing stage, the proposed method generates a specified range of trajectory with the transition of the flight state. The full glide trajectory consists of several optimal trajectory sequences. The newly focused geographic constraints in actual flight are discussed thereafter. Numerical examples of free-space flight, target transition flight, and threat avoidance flight are used to show the feasible application of multistage pseudospectral method in reentry trajectory optimization. PMID:24574929

Choosing the Optimal Number of B-spline Control Points (Part 1: Methodology and Approximation of Curves)

NASA Astrophysics Data System (ADS)

Harmening, Corinna; Neuner, Hans

2016-09-01

Due to the establishment of terrestrial laser scanner, the analysis strategies in engineering geodesy change from pointwise approaches to areal ones. These areal analysis strategies are commonly built on the modelling of the acquired point clouds. Freeform curves and surfaces like B-spline curves/surfaces are one possible approach to obtain space continuous information. A variety of parameters determines the B-spline's appearance; the B-spline's complexity is mostly determined by the number of control points. Usually, this number of control points is chosen quite arbitrarily by intuitive trial-and-error-procedures. In this paper, the Akaike Information Criterion and the Bayesian Information Criterion are investigated with regard to a justified and reproducible choice of the optimal number of control points of B-spline curves. Additionally, we develop a method which is based on the structural risk minimization of the statistical learning theory. Unlike the Akaike and the Bayesian Information Criteria this method doesn't use the number of parameters as complexity measure of the approximating functions but their Vapnik-Chervonenkis-dimension. Furthermore, it is also valid for non-linear models. Thus, the three methods differ in their target function to be minimized and consequently in their definition of optimality. The present paper will be continued by a second paper dealing with the choice of the optimal number of control points of B-spline surfaces.

A Method for Suppressing Line Overload Phenomena Using NAS Battery Systems

NASA Astrophysics Data System (ADS)

Ohtaka, Toshiya; Iwamoto, Shinichi

In this paper, we pay attention to the superior operating control function and instantaneous discharging characteristics of NAS battery systems, and propose a method for determining installation planning and operating control schemes of NAS battery systems for suppressing line overload phenomena. In the stage of planning, a target contingency is identified, and an optimal allocation and capacity of NAS battery systems and an amount of generation changes are determined for the contingency. In the stage of operation, the control strategy of NAS battery system is determined. Simulations are carried out for verifying the validity of the proposed method using the IEEJ 1 machine V system model and an example 2 machine 16 bus system model.

Research on Acceleration Compensation Strategy of Electric Vehicle Based on Fuzzy Control Theory

NASA Astrophysics Data System (ADS)

Zhu, Tianjun; Li, Bin; Zong, Changfu; Wei, Zhicheng

2017-09-01

Nowadays, the driving technology of electric vehicle is developing rapidly. There are many kinds of methods in driving performance control technology. The paper studies the acceleration performance of electric vehicle. Under the premise of energy management, an acceleration power compensation method by fuzzy control theory based on driver intention recognition is proposed, which can meet the driver’s subjective feelings better. It avoids the problem that the pedal opening and power output are single correspondence when the traditional vehicle accelerates. Through the simulation test, this method can significantly improve the performance of acceleration and output torque smoothly in non-emergency acceleration to ensure vehicle comfortable and stable.

A New Unified Analysis of Estimate Errors by Model-Matching Phase-Estimation Methods for Sensorless Drive of Permanent-Magnet Synchronous Motors and New Trajectory-Oriented Vector Control, Part I

NASA Astrophysics Data System (ADS)

Shinnaka, Shinji; Sano, Kousuke

This paper presents a new unified analysis of estimate errors by model-matching phase-estimation methods such as rotor-flux state-observers, back EMF state-observers, and back EMF disturbance-observers, for sensorless drive of permanent-magnet synchronous motors. Analytical solutions about estimate errors, whose validity is confirmed by numerical experiments, are rich in universality and applicability. As an example of universality and applicability, a new trajectory-oriented vector control method is proposed, which can realize directly quasi-optimal strategy minimizing total losses with no additional computational loads by simply orienting one of vector-control coordinates to the associated quasi-optimal trajectory. The coordinate orientation rule, which is analytically derived, is surprisingly simple. Consequently the trajectory-oriented vector control method can be applied to a number of conventional vector control systems using one of the model-matching phase-estimation methods.

Fouling on ion-exchange membranes: Classification, characterization and strategies of prevention and control.

PubMed

Mikhaylin, Sergey; Bazinet, Laurent

2016-03-01

The environmentally friendly ion-exchange membrane (IEM) processes find more and more applications in the modern industries in order to demineralize, concentrate and modify products. Moreover, these processes may be applied for the energy conversion and storage. However, the main drawback of the IEM processes is a formation of fouling, which significantly decreases the process efficiency and increases the process cost. The present review is dedicated to the problematic of IEM fouling phenomena. Firstly, the major types of IEM fouling such as colloidal fouling, organic fouling, scaling and biofouling are discussed along with consideration of the main factors affecting fouling formation and development. Secondly, the review of the possible methods of IEM fouling characterization is provided. This section includes the methods of fouling visualization and characterization as well as methods allowing investigations of characteristics of the fouled IEMs. Eventually, the reader will find the conventional and modern strategies of prevention and control of different fouling types. Copyright © 2015 Elsevier B.V. All rights reserved.

On Motion Planning and Control of Multi-Link Lightweight Robotic Manipulators

NASA Technical Reports Server (NTRS)

Cetinkunt, Sabri

1987-01-01

A general gross and fine motion planning and control strategy is needed for lightweight robotic manipulator applications such as painting, welding, material handling, surface finishing, and spacecraft servicing. The control problem of lightweight manipulators is to perform fast, accurate, and robust motions despite the payload variations, structural flexibility, and other environmental disturbances. Performance of the rigid manipulator model based computed torque and decoupled joint control methods are determined and simulated for the counterpart flexible manipulators. A counterpart flexible manipulator is defined as a manipulator which has structural flexibility, in addition to having the same inertial, geometric, and actuation properties of a given rigid manipulator. An adaptive model following control (AMFC) algorithm is developed to improve the performance in speed, accuracy, and robustness. It is found that the AMFC improves the speed performance by a factor of two over the conventional non-adaptive control methods for given accuracy requirements while proving to be more robust with respect to payload variations. Yet there are clear limitations on the performance of AMFC alone as well, which are imposed by the arm flexibility. In the search to further improve speed performance while providing a desired accuracy and robustness, a combined control strategy is developed. Furthermore, the problem of switching from one control structure to another during the motion and implementation aspects of combined control are discussed.

An Hypothesis on Thinking

ERIC Educational Resources Information Center

Maclennan, Ian

1977-01-01

Suggests that there exists a "finite" number of elementary concepts and distinguishable modes of thinking, that all human beings tend to acquire the same set of elements of thinking and the same strategies with which to understand and control their physical environment, and that the method of analysis used here is a standard scientific method.…

WWTP dynamic disturbance modelling--an essential module for long-term benchmarking development.

PubMed

Gernaey, K V; Rosen, C; Jeppsson, U

2006-01-01

Intensive use of the benchmark simulation model No. 1 (BSM1), a protocol for objective comparison of the effectiveness of control strategies in biological nitrogen removal activated sludge plants, has also revealed a number of limitations. Preliminary definitions of the long-term benchmark simulation model No. 1 (BSM1_LT) and the benchmark simulation model No. 2 (BSM2) have been made to extend BSM1 for evaluation of process monitoring methods and plant-wide control strategies, respectively. Influent-related disturbances for BSM1_LT/BSM2 are to be generated with a model, and this paper provides a general overview of the modelling methods used. Typical influent dynamic phenomena generated with the BSM1_LT/BSM2 influent disturbance model, including diurnal, weekend, seasonal and holiday effects, as well as rainfall, are illustrated with simulation results. As a result of the work described in this paper, a proposed influent model/file has been released to the benchmark developers for evaluation purposes. Pending this evaluation, a final BSM1_LT/BSM2 influent disturbance model definition is foreseen. Preliminary simulations with dynamic influent data generated by the influent disturbance model indicate that default BSM1 activated sludge plant control strategies will need extensions for BSM1_LT/BSM2 to efficiently handle 1 year of influent dynamics.

Nonlinear model predictive control of a wave energy converter based on differential flatness parameterisation

NASA Astrophysics Data System (ADS)

Li, Guang

2017-01-01

This paper presents a fast constrained optimization approach, which is tailored for nonlinear model predictive control of wave energy converters (WEC). The advantage of this approach relies on its exploitation of the differential flatness of the WEC model. This can reduce the dimension of the resulting nonlinear programming problem (NLP) derived from the continuous constrained optimal control of WEC using pseudospectral method. The alleviation of computational burden using this approach helps to promote an economic implementation of nonlinear model predictive control strategy for WEC control problems. The method is applicable to nonlinear WEC models, nonconvex objective functions and nonlinear constraints, which are commonly encountered in WEC control problems. Numerical simulations demonstrate the efficacy of this approach.

Two-strain Tuberculosis Transmission Model under Three Control Strategies

NASA Astrophysics Data System (ADS)

Rayhan, S. N.; Bakhtiar, T.; Jaharuddin

2017-03-01

In 1997, Castillo-Chavez and Feng developed a two-strain tuberculosis (TB) model, which is typical TB and resistant TB. Castillo-Chavez and Feng’s model was then subsequently developed by Jung et al. (2002) by adding two control variables. In this work, Jung et al.’s model was modified by introducing a new control variable so that there are three controls, namely chemoprophylaxis and two treatment strategies, with the application of three different scenarios related to the objective functional form and control application. Pontryagin maximum principle was applied to derive the differential equations system as a condition that must be satisfied by the optimal control variables. Furthermore, the fourth-order Runge-Kutta method was exploited to determine the numerical solution of the optimal control problem. In this numerical solution, it is shown that the controls treated on TB transmission model provide a good effect because latent and infected individuals are decreasing, and the number of individuals that is treated effectively is increasing.

H∞ control for switched fuzzy systems via dynamic output feedback: Hybrid and switched approaches

NASA Astrophysics Data System (ADS)

Xiang, Weiming; Xiao, Jian; Iqbal, Muhammad Naveed

2013-06-01

Fuzzy T-S model has been proven to be a practical and effective way to deal with the analysis and synthesis problems for complex nonlinear systems. As for switched nonlinear system, describing its subsystems as fuzzy T-S models, namely switched fuzzy system, naturally is an alternative method to conventional control approaches. In this paper, the H∞ control problem for a class of switched fuzzy systems is addressed. Hybrid and switched design approaches are proposed with different availability of switching signal information at switching instant. The hybrid control strategy includes two parts: fuzzy controllers for subsystems and state updating controller at switching instant, and the switched control strategy contains the controllers for subsystems. It is demonstrated that the conservativeness is reduced by introducing the state updating behavior but its cost is an online prediction of switching signal. Numerical examples are given to illustrate the effectiveness of proposed approaches and compare the conservativeness of two approaches.

Three different methods for the derivation of control laws for multi-degree-of-freedom systems containing electrorheological dampers

NASA Astrophysics Data System (ADS)

Moosheimer, Johannes; Waller, Heinz

1999-06-01

The minimization of unwanted vibrations is an important technical challenge. Purely passive systems often do not achieve the postulated results. Purely active systems are costly because of the required additional power and the necessary maintenance. Currently it seems that semi-active methods of vibration reduction are as competitive as any other methods. Semi-active damping control can be realized with electro- or magnetorheological fluids. These change their characteristic in the presence of an electric or magnetic field or by bypasses combined with magnetic valves. The methods known in linear control theory cannot be used for the controller design because no explicit external forces can be generated whenever they are needed. Forces can only be generated when relative velocities between the endpoints of the damper exist. It is important to investigate control methods which will reduce vibration with controlled damping. In this paper three different methods for establishing control laws are presented. The first is based on the consideration of power flow in the system. It is discussed in detail. The second method uses Bellmans dynamic optimization. The last transforms a multi degree of freedom system by modal analysis into uncoupled single degree of freedom systems. The control methods developed by these three methods all lead to the same vibration reduction strategy. The control laws are verified with simulation results.

A feedback control strategy for the airfoil system under non-Gaussian colored noise excitation.

PubMed

Huang, Yong; Tao, Gang

2014-09-01

The stability of a binary airfoil with feedback control under stochastic disturbances, a non-Gaussian colored noise, is studied in this paper. First, based on some approximated theories and methods the non-Gaussian colored noise is simplified to an Ornstein-Uhlenbeck process. Furthermore, via the stochastic averaging method and the logarithmic polar transformation, one dimensional diffusion process can be obtained. At last by applying the boundary conditions, the largest Lyapunov exponent which can determine the almost-sure stability of the system and the effective region of control parameters is calculated.

A feedback control strategy for the airfoil system under non-Gaussian colored noise excitation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Yong, E-mail: hy@njust.edu.cn, E-mail: taogang@njust.edu.cn; Tao, Gang, E-mail: hy@njust.edu.cn, E-mail: taogang@njust.edu.cn

2014-09-01

The stability of a binary airfoil with feedback control under stochastic disturbances, a non-Gaussian colored noise, is studied in this paper. First, based on some approximated theories and methods the non-Gaussian colored noise is simplified to an Ornstein-Uhlenbeck process. Furthermore, via the stochastic averaging method and the logarithmic polar transformation, one dimensional diffusion process can be obtained. At last by applying the boundary conditions, the largest Lyapunov exponent which can determine the almost-sure stability of the system and the effective region of control parameters is calculated.

The incorporation of activities to control dengue by community health agents

PubMed Central

Cazola, Luiza Helena de Oliveira; Tamaki, Edson Mamoru; Pontes, Elenir Rose Jardim Cury; de Andrade, Sonia Maria Oliveira

2014-01-01

OBJECTIVE To evaluate the performance of Community Health Agents when dengue control activities were added to their tasks. METHODS Performance was measured comparing the evolution of selected indicators from the Brazilian National Dengue Control Program and the Family Health Strategy for 2002 to 2008 in the municipality of Sao Gabriel do Oeste, MS, Central Western Brazil, with those of Rio Verde de Mato Grosso, neighboring municipality with demographic, socioeconomic and health services similarities. Data were collected from municipal databases of the Information System for Yellow Fever and Dengue and the Information System for Primary Healthcare of the Mato Grosso do Sul State Health Office. The variables selected for the family health strategy activities were: monthly home visits, pregnant women whose antenatal care began in the first trimester, children under one with up-to-date vaccinations and hypertensive patients. Those selected for the Brazilian National Dengue Control Program were: properties inspected with Aedes aegypti and properties not inspected. RESULTS The two municipalities maintained a similar trend in dengue control indicators in the period studied. With regard to the Family Health Strategy, in 2002 Sao Gabriel do Oeste was better off in three of the four indicators studied, however, this situation was reversed at the end of the period when the county was overtaken by Rio Verde de Mato Grosso in three of the four indicators analyzed, including, the monthly average community health worker visits per registered family, the main activity of a Family Health Strategy agent. CONCLUSIONS: Incorporating the National Dengue Control Program into the Family Health Strategy is viable and developed without prejudice to dengue control activities, however, the same did not occur with the activities of family health in Sao Gabriel do Oeste. The additional workload of the community health workers is the most likely hypothesis for the declining performance of these agents in the Family Health Strategy activities. PMID:24789644

Time-varying sliding-coefficient-based decoupled terminal sliding-mode control for a class of fourth-order systems.

PubMed

Bayramoglu, Husnu; Komurcugil, Hasan

2014-07-01

A time-varying sliding-coefficient-based decoupled terminal sliding mode control strategy is presented for a class of fourth-order systems. First, the fourth-order system is decoupled into two second-order subsystems. The sliding surface of each subsystem was designed by utilizing time-varying coefficients. Then, the control target of one subsystem to another subsystem was embedded. Thereafter, a terminal sliding mode control method was utilized to make both subsystems converge to their equilibrium points in finite time. The simulation results on the inverted pendulum system demonstrate that the proposed method exhibits a considerable improvement in terms of a faster dynamic response and lower IAE and ITAE values as compared with the existing decoupled control methods. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Benchmarking Strategies for Measuring the Quality of Healthcare: Problems and Prospects

PubMed Central

Lovaglio, Pietro Giorgio

2012-01-01

Over the last few years, increasing attention has been directed toward the problems inherent to measuring the quality of healthcare and implementing benchmarking strategies. Besides offering accreditation and certification processes, recent approaches measure the performance of healthcare institutions in order to evaluate their effectiveness, defined as the capacity to provide treatment that modifies and improves the patient's state of health. This paper, dealing with hospital effectiveness, focuses on research methods for effectiveness analyses within a strategy comparing different healthcare institutions. The paper, after having introduced readers to the principle debates on benchmarking strategies, which depend on the perspective and type of indicators used, focuses on the methodological problems related to performing consistent benchmarking analyses. Particularly, statistical methods suitable for controlling case-mix, analyzing aggregate data, rare events, and continuous outcomes measured with error are examined. Specific challenges of benchmarking strategies, such as the risk of risk adjustment (case-mix fallacy, underreporting, risk of comparing noncomparable hospitals), selection bias, and possible strategies for the development of consistent benchmarking analyses, are discussed. Finally, to demonstrate the feasibility of the illustrated benchmarking strategies, an application focused on determining regional benchmarks for patient satisfaction (using 2009 Lombardy Region Patient Satisfaction Questionnaire) is proposed. PMID:22666140

Benchmarking strategies for measuring the quality of healthcare: problems and prospects.

PubMed

Lovaglio, Pietro Giorgio

2012-01-01

Over the last few years, increasing attention has been directed toward the problems inherent to measuring the quality of healthcare and implementing benchmarking strategies. Besides offering accreditation and certification processes, recent approaches measure the performance of healthcare institutions in order to evaluate their effectiveness, defined as the capacity to provide treatment that modifies and improves the patient's state of health. This paper, dealing with hospital effectiveness, focuses on research methods for effectiveness analyses within a strategy comparing different healthcare institutions. The paper, after having introduced readers to the principle debates on benchmarking strategies, which depend on the perspective and type of indicators used, focuses on the methodological problems related to performing consistent benchmarking analyses. Particularly, statistical methods suitable for controlling case-mix, analyzing aggregate data, rare events, and continuous outcomes measured with error are examined. Specific challenges of benchmarking strategies, such as the risk of risk adjustment (case-mix fallacy, underreporting, risk of comparing noncomparable hospitals), selection bias, and possible strategies for the development of consistent benchmarking analyses, are discussed. Finally, to demonstrate the feasibility of the illustrated benchmarking strategies, an application focused on determining regional benchmarks for patient satisfaction (using 2009 Lombardy Region Patient Satisfaction Questionnaire) is proposed.

Strategic Studies Quarterly. Volume 6, Number 4, Winter 2012

DTIC Science & Technology

2012-01-01

surfaced in Australia, where a disgruntled employee rigged a computerized control system at a water treatment plant and...strategy" refers to a multilinear whole-of-government method geared to overcome the resistance and effects of a rival’s A2/AD strategy. r * Anti-Access...counterspace tech- nologies, and long-range surface -to-air missiles. To a force that intends to [44] STRATEGIC STUDIES QUARTERLY ♦ WINTER 2012

A vehicle stability control strategy with adaptive neural network sliding mode theory based on system uncertainty approximation

NASA Astrophysics Data System (ADS)

Ji, Xuewu; He, Xiangkun; Lv, Chen; Liu, Yahui; Wu, Jian

2018-06-01

Modelling uncertainty, parameter variation and unknown external disturbance are the major concerns in the development of an advanced controller for vehicle stability at the limits of handling. Sliding mode control (SMC) method has proved to be robust against parameter variation and unknown external disturbance with satisfactory tracking performance. But modelling uncertainty, such as errors caused in model simplification, is inevitable in model-based controller design, resulting in lowered control quality. The adaptive radial basis function network (ARBFN) can effectively improve the control performance against large system uncertainty by learning to approximate arbitrary nonlinear functions and ensure the global asymptotic stability of the closed-loop system. In this paper, a novel vehicle dynamics stability control strategy is proposed using the adaptive radial basis function network sliding mode control (ARBFN-SMC) to learn system uncertainty and eliminate its adverse effects. This strategy adopts a hierarchical control structure which consists of reference model layer, yaw moment control layer, braking torque allocation layer and executive layer. Co-simulation using MATLAB/Simulink and AMESim is conducted on a verified 15-DOF nonlinear vehicle system model with the integrated-electro-hydraulic brake system (I-EHB) actuator in a Sine With Dwell manoeuvre. The simulation results show that ARBFN-SMC scheme exhibits superior stability and tracking performance in different running conditions compared with SMC scheme.

A public health approach to cervical cancer control: considerations of screening and vaccination strategies.

PubMed

Goldie, Sue

2006-11-01

Cervical cancer remains a leading cause of cancer death among women living in low-resource settings. In the last 3 decades, cytologic screening has -in theory -been available and yet more than 6 million women have died of this preventable disease. The necessary resources, infrastructure, and technological expertise, together with the need for repeated screenings at regular intervals, make cytologic screening difficult to implement in poor countries. As noncytologic approaches for the detection of HPV, simple visual screening methods for anogenital lesions caused by HPV, and the availability of an HPV-16/18 vaccine will enhance the linkage between screening and treatment, multiple factors will need to be considered when designing new, or modifying existing prevention strategies. Countryspecific decisions regarding the best strategy for cervical cancer control will need to rely on data from many sources and take into account complex epidemiologic, economic, social, political, and cultural factors, and be made despite uncertainty and incomplete information. A rigorous decision analytic approach using computerbased modeling methods enables linkage of the knowledge gained from empirical studies to real-world situations. This chapter provides an introduction to these methods, reviews lessons learned from cost-effectiveness analyses of cervical cancer screening in developed and developing countries, and emphasizes important qualitative themes to consider in designing cervical cancer prevention policies.

Chemical copatterning strategies using azlactone-based block copolymers

DOE PAGES

Masigol, Mohammadali; Barua, Niloy; Retterer, Scott T.; ...

2017-09-01

Interfaces can be modified with azlactone-functional polymers in order to manipulate the chemical surface reactivity. Azlactone groups are highly reactive toward amine, thiol, and alcohol nucleophiles, providing a versatile coupling chemistry for secondary surface modification. Azlactone-based surface polymers have been explored in numerous applications, including chemical and biological capture, sensing, and cell culture. These applications often require that the polymer is copatterned within a chemically or biologically inert background; however, common fabrication methods degrade azlactone groups during processing steps or result in polymer films with poorly controlled thicknesses. Here, the authors develop fabrication strategies using parylene lift-off and interface-directed assemblymore » methods to generate microscale patterns of azlactone-based block copolymer in chemically or biologically inert backgrounds. The functionality of azlactone groups was preserved during fabrication, and patterned films appeared as uniform, 80–120nm brushlike films. The authors also develop a patterning approach that uses a novel microcontact stamping method to generate cross-linked, three-dimensional structures of azlactone-based polymers with controllable, microscale thicknesses. The authors identify the benefits of each approach and expect these polymers and patterning strategies to provide a versatile toolbox for developing synthetic interfaces with tuned chemical and physical features for sensing, cell culture, or material capture applications.« less

Chemical copatterning strategies using azlactone-based block copolymers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Masigol, Mohammadali; Barua, Niloy; Retterer, Scott T.

Interfaces can be modified with azlactone-functional polymers in order to manipulate the chemical surface reactivity. Azlactone groups are highly reactive toward amine, thiol, and alcohol nucleophiles, providing a versatile coupling chemistry for secondary surface modification. Azlactone-based surface polymers have been explored in numerous applications, including chemical and biological capture, sensing, and cell culture. These applications often require that the polymer is copatterned within a chemically or biologically inert background; however, common fabrication methods degrade azlactone groups during processing steps or result in polymer films with poorly controlled thicknesses. Here, the authors develop fabrication strategies using parylene lift-off and interface-directed assemblymore » methods to generate microscale patterns of azlactone-based block copolymer in chemically or biologically inert backgrounds. The functionality of azlactone groups was preserved during fabrication, and patterned films appeared as uniform, 80–120nm brushlike films. The authors also develop a patterning approach that uses a novel microcontact stamping method to generate cross-linked, three-dimensional structures of azlactone-based polymers with controllable, microscale thicknesses. The authors identify the benefits of each approach and expect these polymers and patterning strategies to provide a versatile toolbox for developing synthetic interfaces with tuned chemical and physical features for sensing, cell culture, or material capture applications.« less

A mathematical model of Clostridium difficile transmission in medical wards and a cost-effectiveness analysis comparing different strategies for laboratory diagnosis and patient isolation

PubMed Central

Carmeli, Yehuda; Leshno, Moshe

2017-01-01

Background Clostridium difficile infection (CDI) is a common and potentially fatal healthcare-associated infection. Improving diagnostic tests and infection control measures may prevent transmission. We aimed to determine, in resource-limited settings, whether it is more effective and cost-effective to allocate resources to isolation or to diagnostics. Methods We constructed a mathematical model of CDI transmission based on hospital data (9 medical wards, 350 beds) between March 2010 and February 2013. The model consisted of three compartments: susceptible patients, asymptomatic carriers and CDI patients. We used our model results to perform a cost-effectiveness analysis, comparing four strategies that were different combinations of 2 test methods (the two-step test and uniform PCR) and 2 infection control measures (contact isolation in multiple-bed rooms or single-bed rooms/cohorting). For each strategy, we calculated the annual cost (of CDI diagnosis and isolation) for a decrease of 1 in the average daily number of CDI patients; the strategy of the two-step test and contact isolation in multiple-bed rooms was the reference strategy. Results Our model showed that the average number of CDI patients increased exponentially as the transmission rate increased. Improving diagnosis by adopting uniform PCR assay reduced the average number of CDI cases per day per 350 beds from 9.4 to 8.5, while improving isolation by using single-bed rooms reduced the number to about 1; the latter was cost saving. Conclusions CDI can be decreased by better isolation and more sensitive laboratory methods. From the hospital perspective, improving isolation is more cost-effective than improving diagnostics. PMID:28187144

Controlling the cell adhesion property of silk films by graft polymerization.

PubMed

Dhyani, Vartika; Singh, Neetu

2014-04-09

We report here a graft polymerization method to improve the cell adhesion property of Bombyx mori silk fibroin films. B. mori silk has evolved as a promising material for tissue engineering because of its biocompatibility and biodegradability. However, silk's hydrophobic character makes cell adhesion and proliferation difficult. Also, the lack of sufficient reactive amino acid residues makes biofunctionalization via chemical modification challenging. Our study describes a simple method that provides increased chemical handles for tuning of the surface chemistry of regenerated silk films (SFs), thus allowing manipulation of their bioactivity. By grafting pAAc and pHEMA via plasma etching, we have increased carboxylic acid and hydroxyl groups on silk, respectively. These modifications allowed us to tune the hydrophilicity of SFs and provide functional groups for bioconjugation. Our strategy also allowed us to develop silk-based surface coatings, where spatial control over cell adhesion can be achieved. This control over cell adhesion in a particular region of the SFs is difficult to obtain via existing methods of modifying the silk fibroin instead of the SF surface. Thus, our strategy will be a valuable addition to the toolkit of biofunctionalization for enhancing SFs' tissue engineering applications.

Computational methods in metabolic engineering for strain design.

PubMed

Long, Matthew R; Ong, Wai Kit; Reed, Jennifer L

2015-08-01

Metabolic engineering uses genetic approaches to control microbial metabolism to produce desired compounds. Computational tools can identify new biological routes to chemicals and the changes needed in host metabolism to improve chemical production. Recent computational efforts have focused on exploring what compounds can be made biologically using native, heterologous, and/or enzymes with broad specificity. Additionally, computational methods have been developed to suggest different types of genetic modifications (e.g. gene deletion/addition or up/down regulation), as well as suggest strategies meeting different criteria (e.g. high yield, high productivity, or substrate co-utilization). Strategies to improve the runtime performances have also been developed, which allow for more complex metabolic engineering strategies to be identified. Future incorporation of kinetic considerations will further improve strain design algorithms. Copyright © 2015 Elsevier Ltd. All rights reserved.

Freeze-drying of “pearl milk tea”: A general strategy for controllable synthesis of porous materials

PubMed Central

Zhou, Yingke; Tian, Xiaohui; Wang, Pengcheng; Hu, Min; Du, Guodong

2016-01-01

Porous materials have been widely used in many fields, but the large-scale synthesis of materials with controlled pore sizes, pore volumes, and wall thicknesses remains a considerable challenge. Thus, the controllable synthesis of porous materials is of key general importance. Herein, we demonstrate the “pearl milk tea” freeze-drying method to form porous materials with controllable pore characteristics, which is realized by rapidly freezing the uniformly distributed template-containing precursor solution, followed by freeze-drying and suitable calcination. This general and convenient method has been successfully applied to synthesize various porous phosphate and oxide materials using different templates. The method is promising for the development of tunable porous materials for numerous applications of energy, environment, and catalysis, etc. PMID:27193866

Discovering successful strategies for diabetic self-management: a qualitative comparative study

PubMed Central

Baer, Roberta; Nash, Anita; Perez, Noe

2017-01-01

Objective This project explored lifestyles of patients in good and poor control to identify naturally occurring practices and strategies that result in successful diabetes management. Research design and methods Semistructured interviews with adult patients with type 2 diabetes explored diet, food preparation, physical activity, medication use and glucose monitoring. Patients (n=56) were classified into good (A1C <7.0%), fair (7.0%8.0%) control groups and matched across groups on diabetes duration (±5 years) and medication modality (none, oral, insulin±oral) to control for non-lifestyle factors. A qualitative comparative analysis identified practices that distinguished glycemic groups. Results Good control patients were more likely to test their glucose two or more times a day and reduce their sodium intake, as well as increase fruits and vegetables and limit portion sizes, some attaining good control without exercise. Fair control patients discussed several dietary strategies including limiting sweets, drinking non-caloric beverages, reducing carbs, ‘cheating’ (eating only a few sweets/limiting carbs in one meal to have more in another meal) and tested their glucose once a day. Poor control patients were more likely to skip antidiabetic medications and not test their glucose. Conclusions Although clinical trials indicate most self-management practices have limited effectiveness over time, increased glucose monitoring is a valuable component in daily management. Research is needed on effectiveness of dietary strategies that emphasize sodium monitoring and allow some degree of cheating. Reoffering diabetes education classes and providing pill boxes as memory aids may help improve poor control. PMID:28761649

ESMPE: A combined strategy for school tuberculosis prevention and control proposed by Dalian, China.

PubMed

Wang, Xichen; Jiang, Hongbo; Wang, Xuemei; Liu, Hongyu; Zhou, Ling; Lu, Xiwei

2017-01-01

Although China has paid more attention on the prevention and control of tuberculosis (TB) in schools, several unsolved questions in this field still threaten the progress of TB control. Therefore, there is an urgent need to develop a systematic and practical strategy for Chinese school TB prevention and control system. In this study, we aimed to assess the feasibility of a combined strategy named ESMPE (examination, screening, monitoring, prevention and education) that adhere to the basic principles of Chinese schools TB control strategy. The ESMPE strategy included five sections, namely TB screening during physical examination for the school freshmen entrances, screening of close contacts, monitoring of high-risk schools, preventive treatment and TB education. The effectiveness of ESMPE strategy was evaluated from 2011 to 2016. The original data were provided by the Dalian Tuberculosis Hospital. Descriptive analysis and nonparametric tests were used for comparing statistical differences of results between different years. The detection rate of active pulmonary TB in school freshmen was decreased from 2011 to 2016 (χ2 = 41.941, P = 6.0551E-8). 97.22% (17,043/17,530) of close contacts experienced close contacts screening, and the secondary attack rate (SAR) of TB in schools fell by 146.35/105 from 2011 to 2012, and finally reduced to 85.57/105 in 2016. There was a significant correlation between SAR of student TB and the rate of screened close contacts (r = -0.924, P = 0.009). TB incidence of five monitored schools had a substantial decline after receiving monitoring, and this declining trend continued in 2016. Due to the TB education and advanced screening methods, the mean of diagnostic delay time in students with TB was shortened (15.71 days), while still fewer latent TB infection students received preventive treatment (30.38%). The ESMPE strategy has shown a favorable effect on TB prevention and control in Dalian schools. More systematic evidence is needed on the effect of this strategy in reducing the incidence of TB in schools from other settings prior to its further scaling-up in China.

Simulation Comparison of Wake Mitigation Control Strategies for a Two-Turbine Case

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fleming, Paul; Gebraad, Pieter M. O.; Lee, Sang

2015-12-01

Wind turbines arranged in a wind plant impact each other through their wakes. Wind plant control is an active research field that attempts to improve wind plant performance by coordinating control of individual turbines to take into account these turbine–wake interactions. High-fidelity simulations of a two-turbine fully waked scenario are used to investigate several wake mitigation strategies, in this paper, including modification of yaw and tilt angles of an upstream turbine to induce wake skew, as well as repositioning of the downstream turbine. The simulation results are compared through change relative to a baseline operation in terms of overall powermore » capture and loading on the upstream and downstream turbine. Results demonstrated improved power production for all methods. Moreover, analysis of control options, including individual pitch control, shows potential to minimize the increase of, or even reduce, turbine loads.« less

An integrated control scheme for space robot after capturing non-cooperative target

NASA Astrophysics Data System (ADS)

Wang, Mingming; Luo, Jianjun; Yuan, Jianping; Walter, Ulrich

2018-06-01

How to identify the mass properties and eliminate the unknown angular momentum of space robotic system after capturing a non-cooperative target is of great challenge. This paper focuses on designing an integrated control framework which includes detumbling strategy, coordination control and parameter identification. Firstly, inverted and forward chain approaches are synthesized for space robot to obtain dynamic equation in operational space. Secondly, a detumbling strategy is introduced using elementary functions with normalized time, while the imposed end-effector constraints are considered. Next, a coordination control scheme for stabilizing both base and end-effector based on impedance control is implemented with the target's parameter uncertainty. With the measurements of the forces and torques exerted on the target, its mass properties are estimated during the detumbling process accordingly. Simulation results are presented using a 7 degree-of-freedom kinematically redundant space manipulator, which verifies the performance and effectiveness of the proposed method.

The interplay between mosquitoes, entomopathogens and symbiotic microbes: A niche for the development of novel microbial-derived vector control strategies

USDA-ARS?s Scientific Manuscript database

The current outbreak of Zika virus in the Americas has highlighted the need for improved methods of control. This concern is exacerbated if we consider that all three major arboviruses (Zika, dengue, and chikungunya virus) are transmitted efficiently by two wide spread mosquito vectors: Aedes aegypt...

Method of operating an oil shale kiln

DOEpatents

Reeves, Adam A.

1978-05-23

Continuously determining the bulk density of raw and retorted oil shale, the specific gravity of the raw oil shale and the richness of the raw oil shale provides accurate means to control process variables of the retorting of oil shale, predicting oil production, determining mining strategy, and aids in controlling shale placement in the kiln for the retorting.

Maximum power extraction under different vector-control schemes and grid-synchronization strategy of a wind-driven Brushless Doubly-Fed Reluctance Generator.

PubMed

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.

Can Land Managers Control Japanese Knotweed? Lessons from Control Tests in Belgium

NASA Astrophysics Data System (ADS)

Delbart, Emmanuel; Mahy, Grégory; Weickmans, Bernard; Henriet, François; Crémer, Sébastien; Pieret, Nora; Vanderhoeven, Sonia; Monty, Arnaud

2012-12-01

Japanese knotweed Fallopia japonica is an extremely abundant invasive plant in Belgium and surrounding countries. To date, no eradication method is available for land managers facing the invasion of this rhizomatous plant. We tested different chemical herbicides with two application methods (spraying and stem injection), as well as mechanical treatments, on knotweed clones throughout southern Belgium. The tested control methods were selected to be potentially usable by managers, e.g., using legally accepted rates for herbicides. Stem volume, height and density reduction were assessed after one or two years, depending on the control method. Labor estimations were made for each control method. No tested control method completely eradicated the clones. Stem injection with glyphosate-based herbicide (3.6 kg ha-1 of acid equivalent glyphosate) caused the most damage, i.e., no sprouting shoots were observed the year following the injection. The following year, though, stunted shoots appeared. Among the mechanical control methods, repeated cuts combined with native tree transplanting most appreciably reduced knotweed development. The most efficient methods we tested could curb knotweed invasion, but are not likely to be effective in eradicating the species. As such, they should be included in a more integrated restoration strategy, together with prevention and public awareness campaigns.

Development and beyond: Strategy for long-term maintenance of an online laser diffraction particle size method in a spray drying manufacturing process.

PubMed

Medendorp, Joseph; Bric, John; Connelly, Greg; Tolton, Kelly; Warman, Martin

2015-08-10

The purpose of this manuscript is to present the intended use and long-term maintenance strategy of an online laser diffraction particle size method used for process control in a spray drying process. A Malvern Insitec was used for online particle size measurements and a Malvern Mastersizer was used for offline particle size measurements. The two methods were developed in parallel with the Mastersizer serving as the reference method. Despite extensive method development across a range of particle sizes, the two instruments demonstrated different sensitivities to material and process changes over the product lifecycle. This paper will describe the procedure used to ensure consistent alignment of the two methods, thus allowing for continued use of online real-time laser diffraction as a surrogate for the offline system over the product lifecycle. Copyright © 2015 Elsevier B.V. All rights reserved.

Objective Model Selection for Identifying the Human Feedforward Response in Manual Control.

PubMed

Drop, Frank M; Pool, Daan M; van Paassen, Marinus Rene M; Mulder, Max; Bulthoff, Heinrich H

2018-01-01

Realistic manual control tasks typically involve predictable target signals and random disturbances. The human controller (HC) is hypothesized to use a feedforward control strategy for target-following, in addition to feedback control for disturbance-rejection. Little is known about human feedforward control, partly because common system identification methods have difficulty in identifying whether, and (if so) how, the HC applies a feedforward strategy. In this paper, an identification procedure is presented that aims at an objective model selection for identifying the human feedforward response, using linear time-invariant autoregressive with exogenous input models. A new model selection criterion is proposed to decide on the model order (number of parameters) and the presence of feedforward in addition to feedback. For a range of typical control tasks, it is shown by means of Monte Carlo computer simulations that the classical Bayesian information criterion (BIC) leads to selecting models that contain a feedforward path from data generated by a pure feedback model: "false-positive" feedforward detection. To eliminate these false-positives, the modified BIC includes an additional penalty on model complexity. The appropriate weighting is found through computer simulations with a hypothesized HC model prior to performing a tracking experiment. Experimental human-in-the-loop data will be considered in future work. With appropriate weighting, the method correctly identifies the HC dynamics in a wide range of control tasks, without false-positive results.

Aeration control strategies to stimulate simultaneous nitrification-denitrification via nitrite during the formation of aerobic granular sludge.

PubMed

Dobbeleers, Thomas; D'aes, Jolien; Miele, Solange; Caluwé, Michel; Akkermans, Veerle; Daens, Dominique; Geuens, Luc; Dries, Jan

2017-09-01

In this study, a sequencing batch reactor (SBR), treating synthetic wastewater (COD/N = 5), was operated in two stages. During stage I, an aeration control strategy based on oxygen uptake rate (OUR) was applied, to accomplish nitrogen removal via nitrite >80%. In stage II, the development of aerobic granular sludge (AGS) was examined while two aeration control strategies (OUR and pH slope) maintained the nitrite pathway and optimized the simultaneous nitrification-denitrification (SND) performance. Stimulation of slow-growing organisms, (denitrifying) polyphosphate-accumulating organisms (D)PAO and (denitrifying) glycogen-accumulating organisms (D)GAO leads to full granulation (at day 200, SVI 10  = 47.0 mL/g and SVI 30  = 43.1 mL/g). The average biological nutrient removal efficiencies, for nitrogen and phosphorus, were 94.6 and 83.7%, respectively. Furthermore, the benefits of an increased dissolved oxygen concentration (1.0-2.0 mg O 2 /L) were shown as biomass concentrations increased with approximately 2 g/L, and specific ammonium removal rate and phosphorus uptake rate increased with 33 and 44%, respectively. It was shown that the combination of both aeration phase-length control strategies provided an innovative method to achieve SND via nitrite in AGS.

Structural sensing of interior sound for active control of noise in structural-acoustic cavities.

PubMed

Bagha, Ashok K; Modak, S V

2015-07-01

This paper proposes a method for structural sensing of acoustic potential energy for active control of noise in a structural-acoustic cavity. The sensing strategy aims at global control and works with a fewer number of sensors. It is based on the established concept of radiation modes and hence does not add too many states to the order of the system. Acoustic potential energy is sensed using a combination of a Kalman filter and a frequency weighting filter with the structural response measurements as the inputs. The use of Kalman filter also makes the system robust against measurement noise. The formulation of the strategy is presented using finite element models of the system including that of sensors and actuators so that it can be easily applied to practical systems. The sensing strategy is numerically evaluated in the framework of Linear Quadratic Gaussian based feedback control of interior noise in a rectangular box cavity with a flexible plate with single and multiple pairs of piezoelectric sensor-actuator patches when broadband disturbances act on the plate. The performance is compared with an "acoustic filter" that models the complete transfer function from the structure to the acoustic domain. The sensing performance is also compared with a direct estimation strategy.

Control method for physical systems and devices

DOEpatents

Guckenheimer, John

1997-01-01

A control method for stabilizing systems or devices that are outside the control domain of a linear controller is provided. When applied to nonlinear systems, the effectiveness of this method depends upon the size of the domain of stability that is produced for the stabilized equilibrium. If this domain is small compared to the accuracy of measurements or the size of disturbances within the system, then the linear controller is likely to fail within a short period. Failure of the system or device can be catastrophic: the system or device can wander far from the desired equilibrium. The method of the invention presents a general procedure to recapture the stability of a linear controller, when the trajectory of a system or device leaves its region of stability. By using a hybrid strategy based upon discrete switching events within the state space of the system or device, the system or device will return from a much larger domain to the region of stability utilized by the linear controller. The control procedure is robust and remains effective under large classes of perturbations of a given underlying system or device.

Dengue knowledge, attitudes and practices and their impact on community-based vector control in rural Cambodia

PubMed Central

Doum, Dyna; Keo, Vanney; Sokha, Ly; Sam, BunLeng; Chan, Vibol; Alexander, Neal; Bradley, John; Liverani, Marco; Prasetyo, Didot Budi; Rachmat, Agus; Lopes, Sergio; Hii, Jeffrey; Rithea, Leang; Shafique, Muhammad; Hustedt, John

2018-01-01

Background Globally there are an estimated 390 million dengue infections per year, of which 96 million are clinically apparent. In Cambodia, estimates suggest as many as 185,850 cases annually. The World Health Organization global strategy for dengue prevention aims to reduce mortality rates by 50% and morbidity by 25% by 2020. The adoption of integrated vector management approach using community-based methods tailored to the local context is one of the recommended strategies to achieve these objectives. Understanding local knowledge, attitudes and practices is therefore essential to designing suitable strategies to fit each local context. Methods and findings A Knowledge, Attitudes and Practices survey in 600 randomly chosen households was administered in 30 villages in Kampong Cham which is one of the most populated provinces of Cambodia. KAP surveys were administered to a sub-sample of households where an entomology survey was conducted (1200 households), during which Aedes larval/pupae and adult female Aedes mosquito densities were recorded. Participants had high levels of knowledge regarding the transmission of dengue, Aedes breeding, and biting prevention methods; the majority of participants believed they were at risk and that dengue transmission is preventable. However, self-reported vector control practices did not match observed practices recorded in our surveys. No correlation was found between knowledge and observed practices either. Conclusion An education campaign regarding dengue prevention in this setting with high knowledge levels is unlikely to have any significant effect on practices unless it is incorporated in a more comprehensive strategy for behavioural change, such a COMBI method, which includes behavioural models as well as communication and marketing theory and practice. Trial registration ISRCTN85307778. PMID:29451879

Effect of Group Mindfulness-Based Stress-Reduction Program and Conscious Yoga on Lifestyle, Coping Strategies, and Systolic and Diastolic Blood Pressures in Patients with Hypertension

PubMed Central

Nejati, Somayeh; Zahiroddin, Alireza; Afrookhteh, Gita; Rahmani, Soheila; Hoveida, Shahrzad

2015-01-01

Background: Healthy lifestyle and ineffective coping strategies are deemed significant variables among patients with hypertension. This study attempted to determine the status of these variables following intervention via the mindfulness-based stress-reduction program (MBSRP) in patients with hypertension. Method: This study was a randomized clinical trial. The study sample, consisting of 30 patients referring to the Hypertension Clinic of Imam Hossein Hospital in 2013, was assigned either to the intervention (recipient of the MBSRP and conscious yoga) or to the control group (recipient of yoga training). The intervention group had 8 training sessions over 8 weeks. Lifestyle and coping strategies as well as blood pressure were measured in the intervention group before intervention and then immediately thereafter and at 2 months' follow-up and were compared to those in the control group at the same time points. Result: The mean age of the patients in the intervention (40% women) and control (53% women) groups was 43.66 ± 5.14 and 43.13 ± 5.04 years, respectively. The results showed that the mean scores of lifestyle (p value < 0.05), emotion-focused coping strategies (p value < 0.001), problem-focused coping strategies (p value < 0.001), diastolic blood pressure (p value < 0.001), and systolic blood pressure (p value < 0.001) were significantly different between the intervention and control groups after the intervention. Conclusion: Applying an intervention based on the MBSRP may further improve the lifestyle and coping strategies of patients with hypertension. PMID:26697087

Productivity Savings from Colorectal Cancer Prevention and Control Strategies

PubMed Central

Bradley, Cathy J.; Lansdorp-Vogelaar, Iris; Yabroff, K. Robin; Dahman, Bassam; Mariotto, Angela; Feuer, Eric J.; Brown, Martin L.

2011-01-01

Background Lost productivity represents a considerable portion of the total economic burden of colorectal cancer (CRC), but cost-effectiveness studies of CRC prevention and control have not included these costs and therefore underestimate potential savings from CRC prevention and control. Purpose To use microsimulation modeling study to estimate and project productivity costs of CRC and to model the savings from four approaches to reducing CRC incidence and mortality: risk factor reduction, improved screening, improved treatment, and a simultaneous approach where all three strategies are implemented. Methods A model was developed to project productivity losses from CRC using the U.S. population with CRC incidence and mortality projected through the year 2020. Outcome measures were CRC mortality, morbidity, and productivity savings. Results With 2005 levels in risk factors, screening, and treatment, 48,748 CRC deaths occurred in 2010, amounting to $21 billion of lost productivity. Using prevention and treatment strategies simultaneously, 3586 deaths could have been avoided in 2010, leading to a savings of $1.4 billion. Cumulatively, by 2020, simultaneous strategies that reduce risk factors and increase screening and treatment could result in 101,353 deaths avoided and $33.9 billion in savings in reduced productivity loss. Improved screening rates alone led to nearly $14.7 billion in savings between 2005 and 2020, followed by risk factor reduction ($12.4 billion) and improved treatment ($8.4 billion). Conclusions The savings in productivity loss from strategies to reduce CRC incidence and mortality are substantial, providing evidence that CRC prevention and control strategies are likely to be cost-saving. PMID:21767717

Optimization of fuel-cell tram operation based on two dimension dynamic programming

NASA Astrophysics Data System (ADS)

Zhang, Wenbin; Lu, Xuecheng; Zhao, Jingsong; Li, Jianqiu

2018-02-01

This paper proposes an optimal control strategy based on the two-dimension dynamic programming (2DDP) algorithm targeting at minimizing operation energy consumption for a fuel-cell tram. The energy consumption model with the tram dynamics is firstly deduced. Optimal control problem are analyzed and the 2DDP strategy is applied to solve the problem. The optimal tram speed profiles are obtained for each interstation which consist of three stages: accelerate to the set speed with the maximum traction power, dynamically adjust to maintain a uniform speed and decelerate to zero speed with the maximum braking power at a suitable timing. The optimal control curves of all the interstations are connected with the parking time to form the optimal control method of the whole line. The optimized speed profiles are also simplified for drivers to follow.

Fuzzy control for nonlinear structure with semi-active friction damper

NASA Astrophysics Data System (ADS)

Zhao, Da-Hai; Li, Hong-Nan

2007-04-01

The implementation of semi-active friction damper for vibration mitigation of seismic structure generally requires an efficient control strategy. In this paper, the fuzzy logic based on Takagi-Sugeno model is proposed for controlling a semi-active friction damper that is installed on a nonlinear building subjected to strong earthquakes. The continuous Bouc-Wen hysteretic model for the stiffness is used to describe nonlinear characteristic of the building. The optimal sliding force with friction damper is determined by nonlinear time history analysis under normal earthquakes. The Takagi-Sugeno fuzzy logic model is employed to adjust the clamping force acted on the friction damper according to the semi-active control strategy. Numerical simulation results demonstrate that the proposed method is very efficient in reducing the peak inter-story drift and acceleration of the nonlinear building structure under earthquake excitations.

Wavelet Transform Analysis of the Power Spectrum of Centre of Pressure Signals to Detect the Critical Point Interval of Postural Control

NASA Astrophysics Data System (ADS)

Singh, Neeraj Kumar; Snoussi, Hichem; Hewson, David; Duchêne, Jacques

The aim of this study was to develop a method to detecting the critical point interval (CPI) when sensory feedback is used as part of a closed-loop postural control strategy. Postural balance was evaluated using centre of pressure (COP) displacements from a force plate for 17 control and 10 elderly subjects under eyes open, eyes closed, and vibration conditions. A modified local-maximum-modulus wavelet transform analysis using the power spectrum of COP signals was used to calculate CPI. Lower CPI values indicate increased closed-loop postural control with a quicker response to sensory input. Such a strategy requires greater energy expenditure due to the repeated muscular interventions to remain stable. The CPI for elderly occurred significantly quicker than for controls, indicating tighter control of posture. Similar results were observed for eyes closed and vibration conditions. The CPI parameter can be used to detect differences in postural control due to ageing.

Synchronization of multiple 3-DOF helicopters under actuator faults and saturations with prescribed performance.

PubMed

Yang, Huiliao; Jiang, Bin; Yang, Hao; Liu, Hugh H T

2018-04-01

The distributed cooperative control strategy is proposed to make the networked nonlinear 3-DOF helicopters achieve the attitude synchronization in the presence of actuator faults and saturations. Based on robust adaptive control, the proposed control method can both compensate the uncertain partial loss of control effectiveness and deal with the system uncertainties. To address actuator saturation problem, the control scheme is designed to ensure that the saturation constraint on the actuation will not be violated during the operation in spite of the actuator faults. It is shown that with the proposed control strategy, both the tracking errors of the leading helicopter and the attitude synchronization errors of each following helicopter are bounded in the existence of faulty actuators and actuator saturations. Moreover, the state responses of the entire group would not exceed the predesigned performance functions which are totally independent from the underlaying interaction topology. Simulation results illustrate the effectiveness of the proposed control scheme. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Electroencephalography(EEG)-based instinctive brain-control of a quadruped locomotion robot.

PubMed

Jia, Wenchuan; Huang, Dandan; Luo, Xin; Pu, Huayan; Chen, Xuedong; Bai, Ou

2012-01-01

Artificial intelligence and bionic control have been applied in electroencephalography (EEG)-based robot system, to execute complex brain-control task. Nevertheless, due to technical limitations of the EEG decoding, the brain-computer interface (BCI) protocol is often complex, and the mapping between the EEG signal and the practical instructions lack of logic associated, which restrict the user's actual use. This paper presents a strategy that can be used to control a quadruped locomotion robot by user's instinctive action, based on five kinds of movement related neurophysiological signal. In actual use, the user drives or imagines the limbs/wrists action to generate EEG signal to adjust the real movement of the robot according to his/her own motor reflex of the robot locomotion. This method is easy for real use, as the user generates the brain-control signal through the instinctive reaction. By adopting the behavioral control of learning and evolution based on the proposed strategy, complex movement task may be realized by instinctive brain-control.

Robust Power Management Control for Stand-Alone Hybrid Power Generation System

NASA Astrophysics Data System (ADS)

Kamal, Elkhatib; Adouane, Lounis; Aitouche, Abdel; Mohammed, Walaa

2017-01-01

This paper presents a new robust fuzzy control of energy management strategy for the stand-alone hybrid power systems. It consists of two levels named centralized fuzzy supervisory control which generates the power references for each decentralized robust fuzzy control. Hybrid power systems comprises: a photovoltaic panel and wind turbine as renewable sources, a micro turbine generator and a battery storage system. The proposed control strategy is able to satisfy the load requirements based on a fuzzy supervisor controller and manage power flows between the different energy sources and the storage unit by respecting the state of charge and the variation of wind speed and irradiance. Centralized controller is designed based on If-Then fuzzy rules to manage and optimize the hybrid power system production by generating the reference power for photovoltaic panel and wind turbine. Decentralized controller is based on the Takagi-Sugeno fuzzy model and permits us to stabilize each photovoltaic panel and wind turbine in presence of disturbances and parametric uncertainties and to optimize the tracking reference which is given by the centralized controller level. The sufficient conditions stability are formulated in the format of linear matrix inequalities using the Lyapunov stability theory. The effectiveness of the proposed Strategy is finally demonstrated through a SAHPS (stand-alone hybrid power systems) to illustrate the effectiveness of the overall proposed method.

Closed-Loop and Robust Control of Quantum Systems

PubMed Central

Wang, Lin-Cheng

2013-01-01

For most practical quantum control systems, it is important and difficult to attain robustness and reliability due to unavoidable uncertainties in the system dynamics or models. Three kinds of typical approaches (e.g., closed-loop learning control, feedback control, and robust control) have been proved to be effective to solve these problems. This work presents a self-contained survey on the closed-loop and robust control of quantum systems, as well as a brief introduction to a selection of basic theories and methods in this research area, to provide interested readers with a general idea for further studies. In the area of closed-loop learning control of quantum systems, we survey and introduce such learning control methods as gradient-based methods, genetic algorithms (GA), and reinforcement learning (RL) methods from a unified point of view of exploring the quantum control landscapes. For the feedback control approach, the paper surveys three control strategies including Lyapunov control, measurement-based control, and coherent-feedback control. Then such topics in the field of quantum robust control as H ∞ control, sliding mode control, quantum risk-sensitive control, and quantum ensemble control are reviewed. The paper concludes with a perspective of future research directions that are likely to attract more attention. PMID:23997680

Analysis of Decentralized Variable Structure Control for Collective Search by Mobile Robots

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feddema, J.; Goldsmith, S.; Robinett, R.

1998-11-04

This paper presents an analysis of a decentralized coordination strategy for organizing and controlling a team of mobile robots performing collective search. The alpha-beta coordination strategy is a family of collective search algorithms that allow teams of communicating robots to implicitly coordinate their search activities through a division of labor based on self-selected roIes. In an alpha-beta team. alpha agents are motivated to improve their status by exploring new regions of the search space. Beta a~ents are conservative, and reiy on the alpha agents to provide advanced information on favorable regions of the search space. An agent selects its currentmore » role dynamically based on its current status value relative to the current status values of the other team members. Status is determined by some function of the agent's sensor readings, and is generally a measurement of source intensity at the agent's current location. Variations on the decision rules determining alpha and beta behavior produce different versions of the algorithm that lead to different global properties. The alpha-beta strategy is based on a simple finite-state machine that implements a form of Variable Structure Control (VSC). The VSC system changes the dynamics of the collective system by abruptly switching at defined states to alternative control laws . In VSC, Lyapunov's direct method is often used to design control surfaces which guide the system to a given goal. We introduce the alpha-beta aIgorithm and present an analysis of the equilibrium point and the global stability of the alpha-beta algorithm based on Lyapunov's method.« less

Analysis of decentralized variable structure control for collective search by mobile robots

NASA Astrophysics Data System (ADS)

Goldsmith, Steven Y.; Feddema, John T.; Robinett, Rush D., III

1998-10-01

This paper presents an analysis of a decentralized coordination strategy for organizing and controlling a team of mobile robots performing collective search. The alpha- beta coordination strategy is a family of collective search algorithms that allow teams of communicating robots to implicitly coordinate their search activities through a division of labor based on self-selected roles. In an alpha- beta team, alpha agents are motivated to improve their status by exploring new regions of the search space. Beta agents are conservative, and rely on the alpha agents to provide advanced information on favorable regions of the search space. An agent selects its current role dynamically based on its current status value relative to the current status values of the other team members. Status is determined by some function of the agent's sensor readings, and is generally a measurement of source intensity at the agent's current location. Variations on the decision rules determining alpha and beta behavior produce different versions of the algorithm that lead to different global properties. The alpha-beta strategy is based on a simple finite-state machine that implements a form of Variable Structure Control (VSC). The VSC system changes the dynamics of the collective system by abruptly switching at defined states to alternative control laws. In VSC, Lyapunov's direct method is often used to design control surfaces which guide the system to a given goal. We introduce the alpha- beta algorithm and present an analysis of the equilibrium point and the global stability of the alpha-beta algorithm based on Lyapunov's method.

National plan to enhance aviation safety through human factors improvements

NASA Technical Reports Server (NTRS)

Foushee, Clay

1990-01-01

The purpose of this section of the plan is to establish a development and implementation strategy plan for improving safety and efficiency in the Air Traffic Control (ATC) system. These improvements will be achieved through the proper applications of human factors considerations to the present and future systems. The program will have four basic goals: (1) prepare for the future system through proper hiring and training; (2) develop a controller work station team concept (managing human errors); (3) understand and address the human factors implications of negative system results; and (4) define the proper division of responsibilities and interactions between the human and the machine in ATC systems. This plan addresses six program elements which together address the overall purpose. The six program elements are: (1) determine principles of human-centered automation that will enhance aviation safety and the efficiency of the air traffic controller; (2) provide new and/or enhanced methods and techniques to measure, assess, and improve human performance in the ATC environment; (3) determine system needs and methods for information transfer between and within controller teams and between controller teams and the cockpit; (4) determine how new controller work station technology can optimally be applied and integrated to enhance safety and efficiency; (5) assess training needs and develop improved techniques and strategies for selection, training, and evaluation of controllers; and (6) develop standards, methods, and procedures for the certification and validation of human engineering in the design, testing, and implementation of any hardware or software system element which affects information flow to or from the human.

Randomized controlled trial comparing tailoring methods of multimedia-based fall prevention education for community-dwelling older adults.

PubMed

Schepens, Stacey L; Panzer, Victoria; Goldberg, Allon

2011-01-01

We attempted to determine whether multimedia fall prevention education using different instructional strategies increases older adults' knowledge of fall threats and their fall prevention behaviors. Fifty-three community-dwelling older adults were randomized to iwo educational groups or a control group. Multimedia-based educational interventions to increase fall threats knowledge and encourage fall prevention behaviors had two tailoring strategies: (1) improve content realism for individual learners (authenticity group) and (2) highlight program goals and benefits while using participants' content selections (motivation group). Knowledge was measured at baseline and 1-mo follow-up. Participants recorded prevention behaviors for 1 mo. Intervention group participants showed greater knowledge gains and posttest knowledge than did control group participants. The motivation group engaged in more prevention behaviors over 1 mo than did the other groups. Tailoring fall prevention education by addressing authenticity and motivation successfully improved fall threats knowledge. Combining motivational strategies with multimedia education increased the effectiveness of the intervention in encouraging fall prevention behaviors.

A molecular insight into papaya leaf curl-a severe viral disease.

PubMed

Varun, Priyanka; Ranade, S A; Saxena, Sangeeta

2017-11-01

Papaya leaf curl disease (PaLCuD) caused by papaya leaf curl virus (PaLCuV) not only affects yield but also plant growth and fruit size and quality of papaya and is one of the most damaging and economically important disease. Management of PaLCuV is a challenging task due to diversity of viral strains, the alternate hosts, and the genomic complexities of the viruses. Several management strategies currently used by plant virologists to broadly control or eliminate the viruses have been discussed. In the absence of such strategies in the case of PaLCuV at present, the few available options to control the disease include methods like removal of affected plants from the field, insecticide treatments against the insect vector (Bemisia tabaci), and gene-specific control through transgenic constructs. This review presents the current understanding of papaya leaf curl disease, genomic components including satellite DNA associated with the virus, wide host and vector range, and management of the disease and suggests possible generic resistance strategies.

Perspectives on Strategies Using Swellable Polymers in Solid Dispersions for Controlled Drug Release.

PubMed

Tran, Thao T D; Tran, Phuong H L

2017-01-01

Poorly water-soluble drugs, which commonly face the issue of poor absorption and low bioavailability, have been under ongoing research of many formulation scientists for the past few decades. Solid dispersion is one of the most effective strategies in concerns for improving bioavailability of poorly water-soluble drugs. Either application of solid dispersions in dissolution enhancement of poorly water-soluble drugs or the use of swellable polymers in controlled drug release has been reported in pharmaceutical designs widely. However, a review of strategies of using swellable polymers in solid dispersion to take a full advantage of these polymers as a current perspective in facilitating drug bioavailability enhancement is still missing. In this review, we aim to provide a summary of techniques used to formulate a swellable polymer in solid dispersion especially a description of a suitable fabrication method in design of a controlled release solid dispersion. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Engineering live cell surfaces with functional polymers via cytocompatible controlled radical polymerization

NASA Astrophysics Data System (ADS)

Niu, Jia; Lunn, David J.; Pusuluri, Anusha; Yoo, Justin I.; O'Malley, Michelle A.; Mitragotri, Samir; Soh, H. Tom; Hawker, Craig J.

2017-06-01

The capability to graft synthetic polymers onto the surfaces of live cells offers the potential to manipulate and control their phenotype and underlying cellular processes. Conventional grafting-to strategies for conjugating preformed polymers to cell surfaces are limited by low polymer grafting efficiency. Here we report an alternative grafting-from strategy for directly engineering the surfaces of live yeast and mammalian cells through cell surface-initiated controlled radical polymerization. By developing cytocompatible PET-RAFT (photoinduced electron transfer-reversible addition-fragmentation chain-transfer polymerization), synthetic polymers with narrow polydispersity (Mw/Mn < 1.3) could be obtained at room temperature in 5 minutes. This polymerization strategy enables chain growth to be initiated directly from chain-transfer agents anchored on the surface of live cells using either covalent attachment or non-covalent insertion, while maintaining high cell viability. Compared with conventional grafting-to approaches, these methods significantly improve the efficiency of grafting polymer chains and enable the active manipulation of cellular phenotypes.

Reduction Patterns of Acute Schistosomiasis in the People's Republic of China

PubMed Central

Abe, Eniola Michael; Yang, Kun; Bergquist, Robert; Qian, Ying-Jun; Zhang, Li-Juan; Xu, Zhi-Min; Xu, Jing; Guo, Jia-Gang; Xiao, Ning; Zhou, Xiao-Nong

2014-01-01

Background Despite significant, steady progress in schistosomiasis control in the People's Republic of China over the past 50 years, available data suggest that the disease has re-emerged with several outbreaks of acute infections in the early new century. In response, a new integrated strategy was introduced. Methods This retrospective study was conducted between Jan 2005 and Dec 2012, to explore the effectiveness of a new integrated control strategy that was implemented by the national control program since 2004. Results A total of 1,047 acute cases were recorded between 2005 and 2012, with an annual reduction in prevalence of 97.7%. The proportion of imported cases of schistosomiasis was higher in 2011 and 2012. Nine clusters of acute infections were detected by spatio-temporal analysis between June and November, indicating that the high risk areas located in the lake and marshland regions. Conclusion This study shows that the new integrated strategy has played a key role in reducing the morbidity of schistosomiasis in the People's Republic of China. PMID:24810958

Framing Progress In Global Tobacco Control To Inform Action On Noncommunicable Diseases.

PubMed

Wipfli, Heather L; Samet, Jonathan

2015-09-01

Much has been learned about the tobacco epidemic, including its consequences, effective measures to control it, and the actors involved. This article identifies lessons learned that are applicable to the other principal external causes of noncommunicable diseases: alcohol abuse, poor nutrition, and physical inactivity. Among these lessons are the development of evidence-based strategies such as proven cessation methods, tax increases, and smoke-free policies; the role of multinational corporations in maintaining markets and undermining control measures; and the need for strategies that reach across the life course and that begin with individuals and extend to higher levels of societal organization. Differences are also clear. Tobacco products are relatively homogeneous and have no direct benefit to consumers, whereas food and alcohol consumed in moderation are not inherently dangerous. Some tobacco-related diseases have the singular predominant cause of smoking, while many noncommunicable diseases have multiple interlocking causes such as poor diet, excess alcohol consumption, insufficient physical activity, and smoking, along with genetics. Thus, the tobacco control model of comprehensive multilevel strategies is applicable to the control of noncommunicable diseases, but the focus must be on multiple risk factors. Project HOPE—The People-to-People Health Foundation, Inc.

Shiftwork in the Norwegian petroleum industry: overcoming difficulties with family and social life – a cross sectional study

PubMed Central

Ljoså, Cathrine Haugene; Lau, Bjørn

2009-01-01

Background Continuous shift schedules are required in the petroleum industry because of its dependency on uninterrupted production. Although shiftwork affects health, less is known about its effects on social and domestic life. Methods Consequently, we studied these relationships in a sample of 1697 (response rate 55.9%) petroleum workers who worked onshore and offshore for a Norwegian oil and gas company. We also examined the roles of coping strategies and locus of control for handling self-reported problems with social and domestic life. A questionnaire containing scales from the Standard Shiftwork Index and Shiftwork Locus of Control was answered electronically. Results In general, only a few participants reported that their shift schedule affected their social and domestic/family life, and several participants had enough time to spend by themselves and with their partner, close family, friends, and children. Despite this general positive trend, differences were found for shift type and individual factors such as locus of control and coping strategies. Internal locus of control was associated positively with all the dependent variables. However, engaging problem-focused coping strategies were associated only slightly with the dependent variables, while disengaging emotion-focused coping strategies were negatively associated with the dependent variables. Conclusion Since most participants reported few problems with social and domestic/family life, the availability of more leisure time may be a positive feature of shiftwork in the Norwegian petroleum industry. Locus of control and the use of coping strategies were important for shiftworkers' social and domestic/family life. PMID:19650903

The immune strategies of mosquito Aedes aegypti against microbial infection.

PubMed

Wang, Yan-Hong; Chang, Meng-Meng; Wang, Xue-Li; Zheng, Ai-Hua; Zou, Zhen

2018-06-01

Yellow fever mosquito Aedes aegypti transmits many devastating arthropod-borne viruses (arboviruses), such as dengue virus, yellow fever virus, Chikungunya virus, and Zika virus, which cause great concern to human health. Mosquito control is an effective method to block the spread of infectious diseases. Ae. aegypti uses its innate immune system to fight against arboviruses, parasites, and fungi. In this review, we briefly summarize the recent findings in the immune response of Ae. aegypti against arboviral and entomopathogenic infections. This review enriches our understanding of the mosquito immune system and provides evidence to support the development of novel mosquito control strategies. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nonlinear fractional order proportion-integral-derivative active disturbance rejection control method design for hypersonic vehicle attitude control

NASA Astrophysics Data System (ADS)

Song, Jia; Wang, Lun; Cai, Guobiao; Qi, Xiaoqiang

2015-06-01

Near space hypersonic vehicle model is nonlinear, multivariable and couples in the reentry process, which are challenging for the controller design. In this paper, a nonlinear fractional order proportion integral derivative (NFOPIλDμ) active disturbance rejection control (ADRC) strategy based on a natural selection particle swarm (NSPSO) algorithm is proposed for the hypersonic vehicle flight control. The NFOPIλDμ ADRC method consists of a tracking-differentiator (TD), an NFOPIλDμ controller and an extended state observer (ESO). The NFOPIλDμ controller designed by combining an FOPIλDμ method and a nonlinear states error feedback control law (NLSEF) is to overcome concussion caused by the NLSEF and conversely compensate the insufficiency for relatively simple and rough signal processing caused by the FOPIλDμ method. The TD is applied to coordinate the contradiction between rapidity and overshoot. By attributing all uncertain factors to unknown disturbances, the ESO can achieve dynamic feedback compensation for these disturbances and thus reduce their effects. Simulation results show that the NFOPIλDμ ADRC method can make the hypersonic vehicle six-degree-of-freedom nonlinear model track desired nominal signals accurately and fast, has good stability, dynamic properties and strong robustness against external environmental disturbances.

A method to identify protein antigens of Dermanyssus gallinae for the protection of birds from poultry mites.

PubMed

Makert, Gustavo R; Vorbrüggen, Susanne; Krautwald-Junghanns, Maria-Elisabeth; Voss, Matthias; Sohn, Kai; Buschmann, Tilo; Ulbert, Sebastian

2016-07-01

The poultry red mite (PRM) Dermanyssus gallinae causes high economic losses and is among the most important parasites in poultry farming worldwide. Different chemical, physical, and biological strategies try to control the expansion of PRM. However, effective solutions to this problem still have to be found. Here, we present a method for the development of an immunological control strategy, based on the identification of mite protein antigens which elicit antibodies with anti-mite activity in the immunized chicken. Hens were immunized with different PRM protein extracts formulated with two different adjuvants, and IgY-antibodies were isolated from the eggs. A PRM in vitro feeding assay which used chicken blood spiked with these IgY-preparations was used to detect antibodies which caused PRM mortality. In vitro feeding of mites with IgY isolated from hens immunized with PRM extract formulated with one of the adjuvants showed a statistically significant increase in the mortality as compared to control mites. After the separation of total PRM extracts in two-dimensional gels, several protein spots were recognized by such IgY preparations. Ten protein spots were subjected to mass spectrometry (MS/MS) for the identification of the corresponding proteins. Complete protein sequences were deduced from genomic and transcriptomic assemblies derived from high throughput sequencing of total PRM DNA and RNA. The results may contribute to the development of an immunological control strategy of D. gallinae.

Damping torque analysis of VSC-based system utilizing power synchronization control

NASA Astrophysics Data System (ADS)

Fu, Q.; Du, W. J.; Zheng, K. Y.; Wang, H. F.

2017-05-01

Power synchronization control is a new control strategy of VSC-HVDC for connecting a weak power system. Different from the vector control method, this control method utilizes the internal synchronization mechanism in ac systems, in principle, similar to the operation of a synchronous machine. So that the parameters of controllers in power synchronization control will change the electromechanical oscillation modes and make an impact on the transient stability of power system. This paper present a mathematical model for small-signal stability analysis of VSC station used power synchronization control and analyse the impact of the dynamic interactions by calculating the contribution of the damping torque from the power synchronization control, besides, the parameters of controllers which correspond to damping torque and synchronous torque in the power synchronization control is defined respectively. At the end of the paper, an example power system is presented to demonstrate and validate the theoretical analysis and associated conclusions are made.

Reconnecting with urban youth enrolled in a randomized controlled trial and overdue for a 12-month follow-up survey

PubMed Central

Ezell, Jerel M.; Saltzgaber, Jacquelyn; Peterson, Edward; Joseph, Christine LM

2013-01-01

Background Retention of study participants in randomized controlled trials (RCTs) is crucial to study validity. Purpose We analyzed the result of four retention strategies used to reconnect with urban teens enrolled in a school-based randomized controlled trial (RCT) and overdue for a 12-month follow-up survey. Methods Traditional retention strategies used to reconnect with teens categorized as “unable to contact” were weekly re-dials of non-working telephone numbers and mailings to the student’s home. Non-traditional retention strategies were obtaining assistance from school administration and communication through Facebook. Results Of the 422 students enrolled, 125 (29.5%) were overdue for a 12-month follow-up survey, but had no working telephone number (unable to contact). We made 196 attempts to contact these 125 students, of which 82 attempts (41.8%) were successful in “reconnecting,” defined as (1) a student contacting research staff as a result of a mailed notice; (2) a research staff member leaving a voicemail at a previously disconnected telephone number; (3) a student responding to Facebook outreach; or (4) research staff obtaining a new telephone number and talking to a person at the new telephone number. We used “ mailed reminder letters” as the referent category, in our analysis. Odds ratios (95% confidence intervals) for the association between the strategy used and success (“reconnecting”) for telephone number re-dials, Facebook, and school administration assistance were 4.60 (1.8–11.8), 1.94 (1.01–3.73), and 2.91 (0.58–14.50), respectively. Limitations Retention strategies were not applied hierarchically or systematically across students, and we were unable to ascertain student preference for a particular strategy. In addition, our findings may be applicable only to study populations with characteristics similar to those of students included in this study. Conclusion Overall, of the 422 students who enrolled in the study, 380 (90%), ultimately completed the 12-month follow-up survey. A mix of traditional retention strategies, such as telephone number re-dials, and more contemporary methods, such as use of Facebook, were effective in reconnecting with urban teenagers enrolled in a school-based RCT, and controlling attrition during the 12-month follow-up survey period. PMID:23983157

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

Code of Federal Regulations, 2012 CFR

2012-07-01

... ranges in the additional two months that the State permits the use of cutback asphalts, and a lack of... test of only the vapor recovery lines and associated equipment. Compliance test method Section H is...

Signal timing under saturated conditions

DOT National Transportation Integrated Search

2008-11-01

This report provides guidance to practitioners for strategies and tactics that will help mitigate the effects of congestion at traffic signals. The focus was on methods that made use of settings wtihin the local intersection controller rather than on...

MERCURY MEASUREMENTS USING DIRECT-ANALYZER METHODOLOGY

EPA Science Inventory

Under EPA's Water Quality Research Program, exposure studies are needed to determine how well control strategies and guidance are working. Consequently, reliable and convenient techniques that minimize waste production are of special interest. While traditional methods for determ...

Effects of Mathematics Integration in a Teaching Methods Course on Mathematics Ability of Preservice Agricultural Education Teachers

ERIC Educational Resources Information Center

Stripling, Christopher T.; Roberts, T. Grady

2014-01-01

The purpose of this study was to determine the effects of incorporating mathematics teaching and integration strategies (MTIS) in a teaching methods course on preservice agricultural teachers' mathematics ability. The research design was quasi-experimental and utilized a nonequivalent control group. The MTIS treatment had a positive effect on the…

Feedback control for manipulating magnetization in spin-exchange optical pumping system

NASA Astrophysics Data System (ADS)

Zhang, Ke; Li, Jun; Jiang, Min; Zhao, Nan; Peng, XinHua

2018-08-01

Control of magnetization plays an important role in the scientific and technological field of manipulating spin systems. In this work, we study the problem of manipulating nuclear magnetization in the spin-exchange optical pumping system, including accelerating the recovery of nuclear polarization and fixing it on a specific desired state. A real-time feedback control strategy is exploited here. We have also done some numerical simulations, with the results clearly demonstrating the effectiveness of our method, that the nuclear magnetization is able to be driven towards the equilibrium state at a much faster speed and also can be stabilized to a target state. We expect that our feedback control method can find applications in gyro experiments.

Adaptive Fuzzy Control for Nonstrict Feedback Systems With Unmodeled Dynamics and Fuzzy Dead Zone via Output Feedback.

PubMed

Wang, Lijie; Li, Hongyi; Zhou, Qi; Lu, Renquan

2017-09-01

This paper investigates the problem of observer-based adaptive fuzzy control for a category of nonstrict feedback systems subject to both unmodeled dynamics and fuzzy dead zone. Through constructing a fuzzy state observer and introducing a center of gravity method, unmeasurable states are estimated and the fuzzy dead zone is defuzzified, respectively. By employing fuzzy logic systems to identify the unknown functions. And combining small-gain approach with adaptive backstepping control technique, a novel adaptive fuzzy output feedback control strategy is developed, which ensures that all signals involved are semi-globally uniformly bounded. Simulation results are given to demonstrate the effectiveness of the presented method.

Intelligent on-line fault tolerant control for unanticipated catastrophic failures.

PubMed

Yen, Gary G; Ho, Liang-Wei

2004-10-01

As dynamic systems become increasingly complex, experience rapidly changing environments, and encounter a greater variety of unexpected component failures, solving the control problems of such systems is a grand challenge for control engineers. Traditional control design techniques are not adequate to cope with these systems, which may suffer from unanticipated dynamic failures. In this research work, we investigate the on-line fault tolerant control problem and propose an intelligent on-line control strategy to handle the desired trajectories tracking problem for systems suffering from various unanticipated catastrophic faults. Through theoretical analysis, the sufficient condition of system stability has been derived and two different on-line control laws have been developed. The approach of the proposed intelligent control strategy is to continuously monitor the system performance and identify what the system's current state is by using a fault detection method based upon our best knowledge of the nominal system and nominal controller. Once a fault is detected, the proposed intelligent controller will adjust its control signal to compensate for the unknown system failure dynamics by using an artificial neural network as an on-line estimator to approximate the unexpected and unknown failure dynamics. The first control law is derived directly from the Lyapunov stability theory, while the second control law is derived based upon the discrete-time sliding mode control technique. Both control laws have been implemented in a variety of failure scenarios to validate the proposed intelligent control scheme. The simulation results, including a three-tank benchmark problem, comply with theoretical analysis and demonstrate a significant improvement in trajectory following performance based upon the proposed intelligent control strategy.

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

PubMed

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

2012-01-01

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

Pathway analysis from lists of microRNAs: common pitfalls and alternative strategy

PubMed Central

Godard, Patrice; van Eyll, Jonathan

2015-01-01

MicroRNAs (miRNAs) are involved in the regulation of gene expression at a post-transcriptional level. As such, monitoring miRNA expression has been increasingly used to assess their role in regulatory mechanisms of biological processes. In large scale studies, once miRNAs of interest have been identified, the target genes they regulate are often inferred using algorithms or databases. A pathway analysis is then often performed in order to generate hypotheses about the relevant biological functions controlled by the miRNA signature. Here we show that the method widely used in scientific literature to identify these pathways is biased and leads to inaccurate results. In addition to describing the bias and its origin we present an alternative strategy to identify potential biological functions specifically impacted by a miRNA signature. More generally, our study exemplifies the crucial need of relevant negative controls when developing, and using, bioinformatics methods. PMID:25800743

Applying the min-projection strategy to improve the transient performance of the three-phase grid-connected inverter.

PubMed

Baygi, Mahdi Oloumi; Ghazi, Reza; Monfared, Mohammad

2014-07-01

Applying the min-projection strategy (MPS) to a three-phase grid-connected inverter to improve its transient performance is the main objective of this paper. For this purpose, the inverter is first modeled as a switched linear system. Then, the feasibility of the MPS technique is investigated and the stability criterion is derived. Hereafter, the fundamental equations of the MPS for the control of the inverter are obtained. The proposed scheme is simulated in PSCAD/EMTDC environment. The validity of the MPS approach is confirmed by comparing the obtained results with those of VOC method. The results demonstrate that the proposed method despite its simplicity provides an excellent transient performance, fully decoupled control of active and reactive powers, acceptable THD level and a reasonable switching frequency. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Assessment of arsenic surface contamination in a museum anthropology department.

PubMed

Gribovich, Andrey; Lacey, Steven; Franke, John; Hinkamp, David

2013-02-01

To assess potential arsenic (As) contamination of work surfaces to improve upon the control strategy at an anthropology department in a large natural history museum. Work practices were observed and control strategy reviewed to inform an occupational hygiene assessment strategy utilizing surface wipe sampling. A total of 35 sampling targets were identified, focusing on surfaces that receive high touch traffic, including workstations, artifact transport carts, and elevator buttons. Arsenic sampling and analysis were performed using reference method Occupational Safety and Health Administration ID-125G. Four of the sampling areas returned detectable levels of As, ranging from 0.052 to 0.350 μg/100 cm. Workplace observations and wipe sampling data enabled the development of recommendations to help to further reduce potential occupational exposure to As. Continuous reduction of surface contamination is prudent for known human carcinogens.

Quality of life of coronary artery disease patients after the implementation of planning strategies for medication adherence 1

PubMed Central

Lourenço, Laura Bacelar de Araujo; Rodrigues, Roberta Cunha Matheus; São-João, Thaís Moreira; Gallani, Maria Cecilia; Cornélio, Marilia Estevam

2015-01-01

OBJECTIVE: to compare the general and specific health-related quality of life (HRQoL) between the Intervention (IG) and Control (CG) groups of coronary artery disease patients after the implementation of Action Planning and Coping Planning strategies for medication adherence and to verify the relationship between adherence and HRQoL. METHOD: this was a controlled and randomized study. RESULTS: the sample (n=115) was randomized into two groups, IG (n=59) and CG (n=56). Measures of medication adherence and general and specific HRQoL were obtained in the baseline and after two months of monitoring. CONCLUSION: the findings showed that the combination of intervention strategies - Action Planning and Coping Planning for medication adherence did not affect the HRQoL of coronary artery disease patients in outpatient monitoring. PMID:25806626

A modal H∞-norm-based performance requirement for damage-tolerant active controller design

NASA Astrophysics Data System (ADS)

Genari, Helói F. G.; Mechbal, Nazih; Coffignal, Gérard; Nóbrega, Eurípedes G. O.

2017-04-01

Damage-tolerant active control (DTAC) is a recent research area that encompasses control design methodologies resulting from the application of fault-tolerant control methods to vibration control of structures subject to damage. The possibility of damage occurrence is not usually considered in the active vibration control design requirements. Damage changes the structure dynamics, which may produce unexpected modal behavior of the closed-loop system, usually not anticipated by the controller design approaches. A modal H∞ norm and a respective robust controller design framework were recently introduced, and this method is here extended to face a new DTAC strategy implementation. Considering that damage affects each vibration mode differently, this paper adopts the modal H∞ norm to include damage as a design requirement. The basic idea is to create an appropriate energy distribution over the frequency range of interest and respective vibration modes, guaranteeing robustness, damage tolerance, and adequate overall performance, taking into account that it is common to have previous knowledge of the structure regions where damage may occur during its operational life. For this purpose, a structural health monitoring technique is applied to evaluate modal modifications caused by damage. This information is used to create modal weighing matrices, conducting to the modal H∞ controller design. Finite element models are adopted for a case study structure, including different damage severities, in order to validate the proposed control strategy. Results show the effectiveness of the proposed methodology with respect to damage tolerance.

Increasing community capacity to reduce tobacco-related health disparities in African American communities.

PubMed

Jones, Pamela R; Waters, Catherine M; Oka, Roberta K; McGhee, Eva M

2010-01-01

The purpose of this study was to understand the processes and interactions that African American tobacco control organizations use to engage African American communities in tobacco control efforts. The study used grounded theory methods to interpret participant's perspectives on tobacco control. The study sample consisted of African American tobacco control program directors from African American tobacco control organizations throughout the United States. Data collection involved 1 interview per participant using a semistructured interview at a location selected by the participant. Each interview lasted approximately 30-90 min. The results showed that organizations used specific strategies to involve African Americans in tobacco control. The tobacco control organizations built community capacity using 3 processes: developing relationships and partnerships, raising awareness, and creating collective power. Contextual, cultural processes, and historical references used by African American tobacco control organizations provide insight into how to engage African American communities in tobacco control efforts and achieve tobacco-related health parity. Public health professionals and nurses should be aware of these and other strategies that may increase the involvement of African American communities in tobacco control. © 2010 Wiley Periodicals, Inc.

Decentralized stabilization of semi-active vibrating structures

NASA Astrophysics Data System (ADS)

Pisarski, Dominik

2018-02-01

A novel method of decentralized structural vibration control is presented. The control is assumed to be realized by a semi-active device. The objective is to stabilize a vibrating system with the optimal rates of decrease of the energy. The controller relies on an easily implemented decentralized switched state-feedback control law. It uses a set of communication channels to exchange the state information between the neighboring subcontrollers. The performance of the designed method is validated by means of numerical experiments performed for a double cantilever system equipped with a set of elastomers with controlled viscoelastic properties. In terms of the assumed objectives, the proposed control strategy significantly outperforms the passive damping cases and is competitive with a standard centralized control. The presented methodology can be applied to a class of bilinear control systems concerned with smart structural elements.

Cleaning and Cleanliness Measurement of Additive Manufactured Parts

NASA Technical Reports Server (NTRS)

Mitchell, Mark A.; Raley, Randy

2016-01-01

The successful acquisition and utilization of piece parts and assemblies for contamination sensitive applications requires application of cleanliness acceptance criteria. Contamination can be classified using many different schemes. One common scheme is classification as organic, ionic and particulate contaminants. These may be present in and on the surface of solid components and assemblies or may be dispersed in various gaseous or liquid media. This discussion will focus on insoluble particle contamination on the surfaces of piece parts and assemblies. Cleanliness of parts can be controlled using two strategies, referred to as gross cleanliness and precision cleanliness. Under a gross cleanliness strategy acceptance is based on visual cleanliness. This approach introduces a number of concerns that render it unsuitable for controlling cleanliness of high technology products. Under the precision cleanliness strategy, subjective, visual assessment of cleanliness is replaced by objective measurement of cleanliness. When a precision cleanliness strategy is adopted there naturally arises the question: How clean is clean enough? The methods for establishing objective cleanliness acceptance limits will be discussed.

An integrated control strategy for the composite braking system of an electric vehicle with independently driven axles

NASA Astrophysics Data System (ADS)

Sun, Fengchun; Liu, Wei; He, Hongwen; Guo, Hongqiang

2016-08-01

For an electric vehicle with independently driven axles, an integrated braking control strategy was proposed to coordinate the regenerative braking and the hydraulic braking. The integrated strategy includes three modes, namely the hybrid composite mode, the parallel composite mode and the pure hydraulic mode. For the hybrid composite mode and the parallel composite mode, the coefficients of distributing the braking force between the hydraulic braking and the two motors' regenerative braking were optimised offline, and the response surfaces related to the driving state parameters were established. Meanwhile, the six-sigma method was applied to deal with the uncertainty problems for reliability. Additionally, the pure hydraulic mode is activated to ensure the braking safety and stability when the predictive failure of the response surfaces occurs. Experimental results under given braking conditions showed that the braking requirements could be well met with high braking stability and energy regeneration rate, and the reliability of the braking strategy was guaranteed on general braking conditions.

Behavior learning in differential games and reorientation maneuvers

NASA Astrophysics Data System (ADS)

Satak, Neha

The purpose of this dissertation is to apply behavior learning concepts to incomplete- information continuous time games. Realistic game scenarios are often incomplete-information games in which the players withhold information. A player may not know its opponent's objectives and strategies prior to the start of the game. This lack of information can limit the player's ability to play optimally. If the player can observe the opponent's actions, it can better optimize its achievements by taking corrective actions. In this research, a framework to learn an opponent's behavior and take corrective actions is developed. The framework will allow a player to observe the opponent's actions and formulate behavior models. The developed behavior model can then be utilized to find the best actions for the player that optimizes the player's objective function. In addition, the framework proposes that the player plays a safe strategy at the beginning of the game. A safe strategy is defined in this research as a strategy that guarantees a minimum pay-off to the player independent of the other player's actions. During the initial part of the game, the player will play the safe strategy until it learns the opponent's behavior. Two methods to develop behavior models that differ in the formulation of the behavior model are proposed. The first method is the Cost-Strategy Recognition (CSR) method in which the player formulates an objective function and a strategy for the opponent. The opponent is presumed to be rational and therefore will play to optimize its objective function. The strategy of the opponent is dependent on the information available to the opponent about other players in the game. A strategy formulation presumes a certain level of information available to the opponent. The previous observations of the opponent's actions are used to estimate the parameters of the formulated behavior model. The estimated behavior model predicts the opponent's future actions. The second method is the Direct Approximation of Value Function (DAVF) method. In this method, unlike the CSR method, the player formulates an objective function for the opponent but does not formulates a strategy directly; rather, indirectly the player assumes that the opponent is playing optimally. Thus, a value function satisfying the HJB equation corresponding to the opponent's cost function exists. The DAVF method finds an approximate solution for the value function based on previous observations of the opponent's control. The approximate solution to the value function is then used to predict the opponent's future behavior. Game examples in which only a single player is learning its opponent's behavior are simulated. Subsequently, examples in which both players in a two-player game are learning each other's behavior are simulated. In the second part of this research, a reorientation control maneuver for a spinning spacecraft will be developed. This will aid the application of behavior learning and differential games concepts to the specific scenario involving multiple spinning spacecraft. An impulsive reorientation maneuver with coasting will be analytically designed to reorient the spin axis of the spacecraft using a single body fixed thruster. Cooperative maneuvers of multiple spacecraft optimizing fuel and relative orientation will be designed. Pareto optimality concepts will be used to arrive at mutually agreeable reorientation maneuvers for the cooperating spinning spacecraft.

Unique strategies to control reproduction in camels.

PubMed

Skidmore, J A; Morton, K M; Billah, M

2010-01-01

The reproductive efficiency of camels is low under natural pastural conditions and so the use of artifical insemination and embryo transfer are becoming increasingly important to improve their breeding potential. Methods to control their reproductive cycle are therefore essential. This review describes characteristics of the ovarian follicular wave pattern in camels and exogenous hormonal control of ovulation. It also summarizes the difficulties involved with artifical insemination and analyzing the highly gelatinous semen, and reports on the latest methods used to try and reduce the viscosity and liquefy camel semen. In addition an account is given of different hormonal and physical methods used to synchronise follicular waves, and various hormone treatments used to broaden the availability of ovulated, asynchronous and non-ovulated recipients are discussed.

‘I’m not a smoker…yet’: a qualitative study on perceptions of tobacco control in Chinese high schools

PubMed Central

2018-01-01

Objective Chinese adolescents’ perceptions about tobacco control at schools are rarely researched. We explored how current antismoking strategies work in middle school environments, as well as the attitudes towards these strategies held by students and teaching staff members. Methods Four focus groups (24 eleventh graders; M age=16 years) and five indepth interviews (teaching staff members with tobacco control experience in schools) were conducted in Kunming, Yunnan Province, China. We used thematic analysis combining inductive and deductive processes, along with field observations and research group discussions, for data analysis. Results With educational approaches and practical strategies, antismoking education reported in the middle schools had limited effectiveness. Although smoking is banned in schools, students can circumvent schools’ controls easily. Notably salient is the pessimistic attitude towards school-based antismoking strategies at school. Detrimental influences within (teachers’ smoking) and beyond schools (high societal smoking prevalence) largely challenged the efforts to manage students’ smoking. Conclusions Current antismoking approaches in schools fail to curb smoking among Chinese high school students. Their effectiveness is undermined by both within-campus and off-campus influences. Students’ perceptions of smoking should be valued as their knowledge of smoking is actively constructed. Future antismoking education at school should incorporate interactive sessions rather than merely didactic approaches about the harms of smoking. Although stricter rules for teachers’ smoking are needed, complementary strategies such as population-level interventions and policy measures in wider society will assist in efforts within schools. PMID:29678968

Aggressive active case detection: a malaria control strategy based on the Brazilian model.

PubMed

Macauley, Cameron

2005-02-01

Since 1996, the Brazilian Ministry of Health has adopted a malaria control strategy known as aggressive active case detection (AACD) in which most or all members of every community are tested and treated for malaria on a monthly basis. The strategy attempts to identify and treat cases of asymptomatic malaria, which, if untreated, continue to transmit the infection. Malaria remains uncontrolled because almost all health care systems in the world rely on passive case detection: the treatment of only symptomatic cases of malaria. Research has shown conclusively that asymptomatic cases exist in any population where malaria transmission is stable and incidence is high: therefore passive case detection simply will not succeed in breaking the cycle of transmission. Numerous case studies show that malaria has been successfully controlled on a regional or national level by mass blood surveys. AACD is an effective malaria control strategy if used in conjunction with other methods, especially when (1) an effective treatment exists, (2) influx of potential carriers of the infection can be monitored, and (3) people are inclined to cooperate with monthly blood testing. AACD requires access to rapid diagnostic tests (RDTs), microscopy supplies, extensive human resources, and prompt, affordable, and effective treatment. AACD is compared to PCD in terms of clinical efficacy and cost effectiveness in a case study of malaria in the Brazilian Yanomami Indians. Where it is feasible, AACD could drastically reduce the incidence of malaria and should be an integral part of the World Health Organization's Roll Back Malaria strategy.

Hybrid Adaptive Flight Control with Model Inversion Adaptation

NASA Technical Reports Server (NTRS)

Nguyen, Nhan

2011-01-01

This study investigates a hybrid adaptive flight control method as a design possibility for a flight control system that can enable an effective adaptation strategy to deal with off-nominal flight conditions. The hybrid adaptive control blends both direct and indirect adaptive control in a model inversion flight control architecture. The blending of both direct and indirect adaptive control provides a much more flexible and effective adaptive flight control architecture than that with either direct or indirect adaptive control alone. The indirect adaptive control is used to update the model inversion controller by an on-line parameter estimation of uncertain plant dynamics based on two methods. The first parameter estimation method is an indirect adaptive law based on the Lyapunov theory, and the second method is a recursive least-squares indirect adaptive law. The model inversion controller is therefore made to adapt to changes in the plant dynamics due to uncertainty. As a result, the modeling error is reduced that directly leads to a decrease in the tracking error. In conjunction with the indirect adaptive control that updates the model inversion controller, a direct adaptive control is implemented as an augmented command to further reduce any residual tracking error that is not entirely eliminated by the indirect adaptive control.

Individual strategy ratings improve the control for task difficulty effects in arithmetic problem solving paradigms.

PubMed

Tschentscher, Nadja; Hauk, Olaf

2015-01-01

Mental arithmetic is a powerful paradigm to study problem solving using neuroimaging methods. However, the evaluation of task complexity varies significantly across neuroimaging studies. Most studies have parameterized task complexity by objective features such as the number size. Only a few studies used subjective rating procedures. In fMRI, we provided evidence that strategy self-reports control better for task complexity across arithmetic conditions than objective features (Tschentscher and Hauk, 2014). Here, we analyzed the relative predictive value of self-reported strategies and objective features for performance in addition and multiplication tasks, by using a paradigm designed for neuroimaging research. We found a superiority of strategy ratings as predictor of performance above objective features. In a Principal Component Analysis on reaction times, the first component explained over 90 percent of variance and factor loadings reflected percentages of self-reported strategies well. In multiple regression analyses on reaction times, self-reported strategies performed equally well or better than objective features, depending on the operation type. A Receiver Operating Characteristic (ROC) analysis confirmed this result. Reaction times classified task complexity better when defined by individual ratings. This suggests that participants' strategy ratings are reliable predictors of arithmetic complexity and should be taken into account in neuroimaging research.

Individual strategy ratings improve the control for task difficulty effects in arithmetic problem solving paradigms

PubMed Central

Tschentscher, Nadja; Hauk, Olaf

2015-01-01

Mental arithmetic is a powerful paradigm to study problem solving using neuroimaging methods. However, the evaluation of task complexity varies significantly across neuroimaging studies. Most studies have parameterized task complexity by objective features such as the number size. Only a few studies used subjective rating procedures. In fMRI, we provided evidence that strategy self-reports control better for task complexity across arithmetic conditions than objective features (Tschentscher and Hauk, 2014). Here, we analyzed the relative predictive value of self-reported strategies and objective features for performance in addition and multiplication tasks, by using a paradigm designed for neuroimaging research. We found a superiority of strategy ratings as predictor of performance above objective features. In a Principal Component Analysis on reaction times, the first component explained over 90 percent of variance and factor loadings reflected percentages of self-reported strategies well. In multiple regression analyses on reaction times, self-reported strategies performed equally well or better than objective features, depending on the operation type. A Receiver Operating Characteristic (ROC) analysis confirmed this result. Reaction times classified task complexity better when defined by individual ratings. This suggests that participants’ strategy ratings are reliable predictors of arithmetic complexity and should be taken into account in neuroimaging research. PMID:26321997

Variable Structure Control of a Hand-Launched Glider

NASA Technical Reports Server (NTRS)

Anderson, Mark R.; Waszak, Martin R.

2005-01-01

Variable structure control system design methods are applied to the problem of aircraft spin recovery. A variable structure control law typically has two phases of operation. The reaching mode phase uses a nonlinear relay control strategy to drive the system trajectory to a pre-defined switching surface within the motion state space. The sliding mode phase involves motion along the surface as the system moves toward an equilibrium or critical point. Analysis results presented in this paper reveal that the conventional method for spin recovery can be interpreted as a variable structure controller with a switching surface defined at zero yaw rate. Application of Lyapunov stability methods show that deflecting the ailerons in the direction of the spin helps to insure that this switching surface is stable. Flight test results, obtained using an instrumented hand-launched glider, are used to verify stability of the reaching mode dynamics.

Verifying detailed fluctuation relations for discrete feedback-controlled quantum dynamics

NASA Astrophysics Data System (ADS)

Camati, Patrice A.; Serra, Roberto M.

2018-04-01

Discrete quantum feedback control consists of a managed dynamics according to the information acquired by a previous measurement. Energy fluctuations along such dynamics satisfy generalized fluctuation relations, which are useful tools to study the thermodynamics of systems far away from equilibrium. Due to the practical challenge to assess energy fluctuations in the quantum scenario, the experimental verification of detailed fluctuation relations in the presence of feedback control remains elusive. We present a feasible method to experimentally verify detailed fluctuation relations for discrete feedback control quantum dynamics. Two detailed fluctuation relations are developed and employed. The method is based on a quantum interferometric strategy that allows the verification of fluctuation relations in the presence of feedback control. An analytical example to illustrate the applicability of the method is discussed. The comprehensive technique introduced here can be experimentally implemented at a microscale with the current technology in a variety of experimental platforms.

Has the DOTS Strategy Improved Case Finding or Treatment Success? An Empirical Assessment

PubMed Central

Obermeyer, Ziad; Abbott-Klafter, Jesse; Murray, Christopher J. L.

2008-01-01

Background Nearly fifteen years after the start of WHO's DOTS strategy, tuberculosis remains a major global health problem. Given the lack of empirical evidence that DOTS reduces tuberculosis burden, considerable debate has arisen about its place in the future of global tuberculosis control efforts. An independent evaluation of DOTS, one of the most widely-implemented and longest-running interventions in global health, is a prerequisite for meaningful improvements to tuberculosis control efforts, including WHO's new Stop TB Strategy. We investigate the impact of the expansion of the DOTS strategy on tuberculosis case finding and treatment success, using only empirical data. Methods and Findings We study the effect of DOTS using time-series cross-sectional methods. We first estimate the impact of DOTS expansion on case detection, using reported case notification data and controlling for other determinants of change in notifications, including HIV prevalence, GDP, and country-specific effects. We then estimate the effect of DOTS expansion on treatment success. DOTS programme variables had no statistically significant impact on case detection in a wide range of models and specifications. DOTS population coverage had a significant effect on overall treatment success rates, such that countries with full DOTS coverage benefit from at least an 18% increase in treatment success (95% CI: 5–31%). Conclusions The DOTS technical package improved overall treatment success. By contrast, DOTS expansion had no effect on case detection. This finding is less optimistic than previous analyses. Better epidemiological and programme data would facilitate future monitoring and evaluation efforts. PMID:18320042

Prevention and control of blood stream infection using the balanced scorecard approach.

PubMed

Rohsiswatmo, Rinawati; Rafika, Sarah; Marsubrin, Putri M T

2014-07-01

to obtain formulation of an effective and efficient strategy to overcome blood stream infection (BSI). operational research design with qualitative and quantitative approach. The study was divided into two stages. Stage I was an operational research with problem solving approach using qualitative and quantitative method. Stage II was performed using quantitative method, a form of an interventional study on strategy implementation, which was previously established in stage I. The effective and efficient strategy for the prevention and control of infection in neonatal unit Cipto Mangunkusumo (CM) Hospital was established using Balanced Scorecard (BSC) approach, which involved several related processes. the BSC strategy was proven to be effective and efficient in substantially reducing BSI from 52.31°/oo to 1.36°/oo in neonates with birth weight (BW) 1000-1499 g (p=0.025), and from 29.96°/oo to 1.66°/oo in BW 1500-1999 g (p=0.05). Gram-negative bacteria still predominated as the main cause of BSI in CMH Neonatal Unit. So far, the sources of the microorganisms were thought to be from the environment of treatment unit (tap water filter and humidifying water in the incubator). Significant reduction was also found in neonatal mortality rate weighing 1000-1499 g at birth, length of stay, hospitalization costs, and improved customer satisfaction. effective and efficient infection prevention and control using BSC approach could significantly reduce the rate of BSI. This approach may be applied for adult patients in intensive care unit with a wide range of adjustment.

Computational design of treatment strategies for proactive therapy on atopic dermatitis using optimal control theory

PubMed Central

Christodoulides, Panayiotis; Hirata, Yoshito; Domínguez-Hüttinger, Elisa; Danby, Simon G.; Cork, Michael J.; Williams, Hywel C.; Aihara, Kazuyuki

2017-01-01

Atopic dermatitis (AD) is a common chronic skin disease characterized by recurrent skin inflammation and a weak skin barrier, and is known to be a precursor to other allergic diseases such as asthma. AD affects up to 25% of children worldwide and the incidence continues to rise. There is still uncertainty about the optimal treatment strategy in terms of choice of treatment, potency, duration and frequency. This study aims to develop a computational method to design optimal treatment strategies for the clinically recommended ‘proactive therapy’ for AD. Proactive therapy aims to prevent recurrent flares once the disease has been brought under initial control. Typically, this is done by using an anti-inflammatory treatment such as a potent topical corticosteroid intensively for a few weeks to ‘get control’, followed by intermittent weekly treatment to suppress subclinical inflammation to ‘keep control’. Using a hybrid mathematical model of AD pathogenesis that we recently proposed, we computationally derived the optimal treatment strategies for individual virtual patient cohorts, by recursively solving optimal control problems using a differential evolution algorithm. Our simulation results suggest that such an approach can inform the design of optimal individualized treatment schedules that include application of topical corticosteroids and emollients, based on the disease status of patients observed on their weekly hospital visits. We demonstrate the potential and the gaps of our approach to be applied to clinical settings. This article is part of the themed issue ‘Mathematical methods in medicine: neuroscience, cardiology and pathology’. PMID:28507230

Emotion Risk-Factor in Patients With Cardiac Diseases: The Role of Cognitive Emotion Regulation Strategies, Positive Affect and Negative Affect (A Case-Control Study)

PubMed Central

Bahremand, Mostafa; Alikhani, Mostafa; Zakiei, Ali; Janjani, Parisa; Aghaei, Abbas

2016-01-01

Application of psychological interventions is essential in classic treatments for patient with cardiac diseases. The present study compared cognitive emotion regulation strategies, positive affect, and negative affect for cardiac patients with healthy subjects. This study was a case-control study. Fifty subjects were selected using convenient sampling method from cardiac (coronary artery disease) patients presenting in Imam Ali medical center of Kermanshah, Iran in the spring 2013. Fifty subjects accompanied the patients to the medical center, selected as control group, did not have any history of cardiac diseases. For collecting data, the cognitive emotion regulation questionnaire and positive and negative affect scales were used. For data analysis, multivariate analysis of variance (MANOVA) was applied using the SPSS statistical software (ver. 19.0). In all cognitive emotion regulation strategies, there was a significant difference between the two groups. A significant difference was also detected regarding positive affect between the two groups, but no significant difference was found regarding negative affect. We found as a result that, having poor emotion regulation strategies is a risk factor for developing heart diseases. PMID:26234976

Memory training interventions for older adults: a meta-analysis.

PubMed

Gross, Alden L; Parisi, Jeanine M; Spira, Adam P; Kueider, Alexandra M; Ko, Jean Y; Saczynski, Jane S; Samus, Quincy M; Rebok, George W

2012-01-01

A systematic review and meta-analysis of memory training research was conducted to characterize the effect of memory strategies on memory performance among cognitively intact, community-dwelling older adults, and to identify characteristics of individuals and of programs associated with improved memory. The review identified 402 publications, of which 35 studies met criteria for inclusion. The overall effect size estimate, representing the mean standardized difference in pre-post change between memory-trained and control groups, was 0.31 standard deviations (SD; 95% confidence interval (CI): 0.22, 0.39). The pre-post training effect for memory-trained interventions was 0.43 SD (95% CI: 0.29, 0.57) and the practice effect for control groups was 0.06 SD (95% CI: 0.05, 0.16). Among 10 distinct memory strategies identified in studies, meta-analytic methods revealed that training multiple strategies was associated with larger training gains (p=0.04), although this association did not reach statistical significance after adjusting for multiple comparisons. Treatment gains among memory-trained individuals were not better after training in any particular strategy, or by the average age of participants, session length, or type of control condition. These findings can inform the design of future memory training programs for older adults.

Emotion Risk-Factor in Patients with Cardiac Diseases: The Role of Cognitive Emotion Regulation Strategies, Positive Affect and Negative Affect (A Case-Control Study).

PubMed

Bahremand, Mostafa; Alikhani, Mostafa; Zakiei, Ali; Janjani, Parisa; Aghei, Abbas

2015-05-17

Application of psychological interventions is essential in classic treatments for patient with cardiac diseases. The present study compared cognitive emotion regulation strategies, positive affect, and negative affect for cardiac patients with healthy subjects. This study was a case-control study. Fifty subjects were selected using convenient sampling method from cardiac (coronary artery disease) patients presenting in Imam Ali medical center of Kermanshah, Iran in the spring 2013. Fifty subjects accompanied the patients to the medical center, selected as control group, did not have any history of cardiac diseases. For collecting data, the cognitive emotion regulation questionnaire and positive and negative affect scales were used. For data analysis, multivariate analysis of variance (MANOVA) Was applied using the SPSS statistical software (ver. 19.0). In all cognitive emotion regulation strategies, there was a significant difference between the two groups. A significant difference was also detected regarding positive affect between the two groups, but no significant difference was found regarding negative affect. We found as a result that, having poor emotion regulation strategies is a risk factor for developing heart diseases.

The impact of cognitive remediation on cerebral activity in schizophrenia: Systematic review of the literature.

PubMed

Bon, Laura; Franck, Nicolas

2018-03-01

cognitive remediation involves either intensive training of impaired functions or implementing strategies to compensate for these impairments. In cases of schizophrenia, both methods have demonstrated benefits in terms of behavior and cerebral activity. However, despite the major differences between these two approaches, their impact has not yet been compared. We searched the PsychInfo, Pubmed, and ScienceDirect databases using the key words "cognitive remediation," "schizophrenia," "cerebral activity," and "magnetic resonance imaging," in order to select studies investigating the effects of cognitive remediation on patients with schizophrenia. The studies selected had to present their approach in detail and measure its impact in terms of both cerebral activity and cognitive function, both before and after therapy. We divided the studies into two groups, those using the strategy method and those using the training method. Eight studies were included in the review, four for the strategy method (88 patients, 44 of whom underwent remediation) and 4 for the training method (87 patients, 43 of whom underwent remediation). The analysis of the results of this study indicates that the training method is capable of activating more the targeted brain areas than the strategy method. However, the latter appears to encourage more extensive activation of the cerebral networks. The studies used for this review vary widely in terms of the imaging methods and protocol. However, differences were found between the two methods and lead us to suggest that further studies, with proper bias control, should be conducted to systematically compare the two approaches.

Process identification of the SCR system of coal-fired power plant for de-NOx based on historical operation data.

PubMed

Li, Jian; Shi, Raoqiao; Xu, Chuanlong; Wang, Shimin

2018-05-08

The selective catalytic reduction (SCR) system, as one principal flue gas treatment method employed for the NO x emission control of the coal-fired power plant, is nonlinear and time-varying with great inertia and large time delay. It is difficult for the present SCR control system to achieve satisfactory performance with the traditional feedback and feedforward control strategies. Although some improved control strategies, such as the Smith predictor control and the model predictive control, have been proposed for this issue, a well-matched identification model is essentially required to realize a superior control of the SCR system. Industrial field experiment is an alternative way to identify the SCR system model in the coal-fired power plant. But it undesirably disturbs the operation system and is costly in time and manpower. In this paper, a process identification model of the SCR system is proposed and developed by applying the asymptotic method to the sufficiently excited data, selected from the original historical operation database of a 350 MW coal-fired power plant according to the condition number of the Fisher information matrix. Numerical simulations are carried out based on the practical historical operation data to evaluate the performance of the proposed model. Results show that the proposed model can efficiently achieve the process identification of the SCR system.

Coping Strategies Associated With Suicidal Behaviour in Adolescent Inpatients With Borderline Personality Disorder

PubMed Central

Knafo, Alexandra; Guilé, Jean-Marc; Breton, Jean-Jacques; Labelle, Réal; Belloncle, Vincent; Bodeau, Nicolas; Boudailliez, Bernard; de la Rivière, Sébastien Garny; Kharij, Brahim; Mille, Christian; Mirkovic, Bojan; Pripis, Cornelia; Renaud, Johanne; Vervel, Christine; Cohen, David; Gérardin, Priscille

2015-01-01

Objectives: To compare the coping strategies of adolescents with borderline personality disorder (BPD) to the coping strategies of adolescents without BPD, and to explore the association of coping with suicidal ideation and attempts among adolescents with BPD. Method: Adolescent inpatients (n = 167) aged 13 to 17 years were admitted after suicide attempts and evaluated within 10 days, using the abbreviated version of the Diagnostic Interview for Borderlines–Revised, the Schedule for Affective Disorders and Schizophrenia for School-Age Children–Present and Lifetime Version supported by a team consensus best estimate method for the primary diagnosis, the Adolescent Coping Scale, and the Columbia-Suicide Severity Rating Scale. Results: Firstly, compared with adolescents without BPD, adolescents with BPD relied more on nonproductive coping strategies, mostly avoidant strategies, and less on productive coping strategies. Secondly, coping appeared as a factor associated with suicidal ideation in adolescents with BPD. While while controlling for age, sex, and depression, multivariate analyses showed a significant positive association between the coping strategy to focusing on solving the problem and suicidal ideation. Conclusion: The use of avoidant strategies by adolescents with BPD could be viewed as attempts to increase emotional regulation. Problem-solving strategies in the immediate aftermath of a suicide attempt may prevent adolescents with BPD from overcoming a crisis and may increase suicidal ideation. PMID:25886671

Improving Strategies via SMT Solving

NASA Astrophysics Data System (ADS)

Gawlitza, Thomas Martin; Monniaux, David

We consider the problem of computing numerical invariants of programs by abstract interpretation. Our method eschews two traditional sources of imprecision: (i) the use of widening operators for enforcing convergence within a finite number of iterations (ii) the use of merge operations (often, convex hulls) at the merge points of the control flow graph. It instead computes the least inductive invariant expressible in the domain at a restricted set of program points, and analyzes the rest of the code en bloc. We emphasize that we compute this inductive invariant precisely. For that we extend the strategy improvement algorithm of Gawlitza and Seidl [17]. If we applied their method directly, we would have to solve an exponentially sized system of abstract semantic equations, resulting in memory exhaustion. Instead, we keep the system implicit and discover strategy improvements using SAT modulo real linear arithmetic (SMT). For evaluating strategies we use linear programming. Our algorithm has low polynomial space complexity and performs for contrived examples in the worst case exponentially many strategy improvement steps; this is unsurprising, since we show that the associated abstract reachability problem is Π2 P -complete.

Optimal strategies for the control of autonomous vehicles in data assimilation

NASA Astrophysics Data System (ADS)

McDougall, D.; Moore, R. O.

2017-08-01

We propose a method to compute optimal control paths for autonomous vehicles deployed for the purpose of inferring a velocity field. In addition to being advected by the flow, the vehicles are able to effect a fixed relative speed with arbitrary control over direction. It is this direction that is used as the basis for the locally optimal control algorithm presented here, with objective formed from the variance trace of the expected posterior distribution. We present results for linear flows near hyperbolic fixed points.

Rogue athletes and recombinant DNA technology: challenges for doping control.

PubMed

Azzazy, Hassan M E; Mansour, Mai M H

2007-10-01

The quest for athletic excellence holds no limit for some athletes, and the advances in recombinant DNA technology have handed these athletes the ultimate doping weapons: recombinant proteins and gene doping. Some detection methods are now available for several recombinant proteins that are commercially available as pharmaceuticals and being abused by dopers. However, researchers are struggling to come up with efficient detection methods in preparation for the imminent threat of gene doping, expected in the 2008 Olympics. This Forum article presents the main detection strategies for recombinant proteins and the forthcoming detection strategies for gene doping as well as the prime analytical challenges facing them.

Strategy of Water Pollution Control Base On Social Economic Activitiy, in Karang Mumus River, Samarinda East Kalimantan, Indonesia

NASA Astrophysics Data System (ADS)

Pramaningsih, Vita; Suprayogi, Slamet; Purnama, Setyawan

2018-02-01

Water Pollution in Karang Mumus River caused society behavior along the river. Daily activity such as bath, washing and defecate at the river. Garbage, sediment, domestic waste and flood are river problems should be solved. Purpose this research is make strategy of water pollution control in the Karang Mumus River. Method used observation in the field, interview to the society, industry, public activity along the river and government of environment department. Further create data using tool of Analysis Hierarchy Process (AHP) to get the strategy to control water pollution in the river. Actors have contribute pollution control are government, industry and society. Criteria to pollution control are society participation, low, human resources and sustainable. Alternative of pollution control are unit garbage storage; license loyalty for industry and waste; communal waste water installation; monitoring of water quality. Result for actor priority are government (0.4); Industry (0.4); Society (0.2). Result for priority criteria are society participation (0.338), low (0.288), human resources (0.205) and sustainable (0.169). Result for priority alternative are unit garbage storage (0.433); license loyalty for industry and waste (0.238); communal waste water installation (0.169); monitoring of water quality (0.161).

[Strategies to prevent the transmission of multidrug-resistant pathogens and their practical implementation in oupatient care].

PubMed

Adler, A C; Spegel, H; Wilke, J; Höller, C; Herr, C

2012-10-01

Multidrugresistant pathogens which are highly relevant for infection control in hospitals and other health-care facilities are a serious public health problem and a big challenge for all players in the health sector. In order to prevent the spread of multi-resistant pathogens the Commission for Hospital Hygiene of the Robert Koch-Institute (RKI) has published guidelines. These recommendations refer to the consequent implementation of an infection control management in all health care settings, including outpatient care. In Germany there are only few data available concerning infection control management and the implementation of preventive strategies in outpatient care. To what extent are national guidelines concerning infection control of multidrugresistant pathogens (i.e. methicillin-resistant Staphylococcus aureus, MRSA) feasible and practicable in outpatient care? And what are the reasons not to practice these strategies. In outpatient care the status of the infection control management and the implementation of prevention strategies was surveyed and assessed. Data were collected by structured interviews - a face to face method. Guidelines concerning infection control management are not always sufficiently implemented in outpatient care. There are multiple reasons for this, such as, e.g., lack of compliance with the recommendations as well as structural problems in the health-care system, and special challenges of outpatient care. Implementation of an infection control management concerning multidrug-resistant pathogens in outpatient care is problematic. Prevention strategies are commonly not known or not adequately implemented into daily practice. Actions to improve the situation should focus at the individual level (e.g., trainings in the context of the initiative "clean hands" ), the institutional level (improving networking, bonus schemes) and the social level (financial and legal support for outpatient care centres to bear the expenses of infection control management, "search and destroy"). © Georg Thieme Verlag KG Stuttgart · New York.

Simultaneous Treatment with Subcutaneous Injection of Golimumab and Intra-articular Injection of Triamcinolone Acetonide (K-Method) in Patients with Rheumatoid Arthritis Undergoing Switching of Biologics: Retrospective Case–Control Study

PubMed Central

Kanbe, Katsuaki; Chiba, Junji; Inoue, Yasuo; Taguchi, Masashi; Yabuki, Akiko; Deguchi, Tomohiko

2016-01-01

BACKGROUND Tight control of severe rheumatoid arthritis (RA) in patients with high disease activity, even when using biologics, is sometimes difficult using a treat-to-target strategy. Switching from one biologic to another is associated with lower efficacy than that in treatment-naive cases. We developed the K-method that involves simultaneous treatment with golimumab and intra-articular joint injection of triamcinolone acetonide (TA) in patients undergoing switching of biologics. We performed this retrospective case–control study to investigate the efficacy of achieving an immediate treatment response using the K-method. METHODS This study involved 20 patients with RA (control group, 10 patients; K-method group, 10 patients). Patients in the control group were switched to golimumab from other biologics without intra-articular injection of TA. The K-method involved injection of 1 mL of TA (40 mg/mL) and 2 mL of 1% lidocaine hydrochloride into swollen or painful joints on the same day as golimumab treatment. A quick response one day after treatment was compared between the two groups according to the disease activity score 28 based on C-reactive protein (DAS28 CRP), clinical disease activity index (CDAI), simplified disease activity index (SDAI), European League Against Rheumatism (EULAR) response, and remission rate. These parameters were investigated for 24 weeks. RESULTS The K-method group showed significant improvements in DAS28 CRP, CDAI, and SDAI at one day, 12 weeks, and 24 weeks compared with the control group. The number of swollen and tender joints and the patient and doctor global visual analog scale scores were also significantly different between the two groups. The remission rates based on DAS28 CRP were 30% at one day, 50% at 12 weeks, and 60% at 24 weeks in the K-method group. The EULAR good/moderate response rates were 80% at one day, 90% at 12 weeks, and 90% at 24 weeks in the K-method group; however, these rates were only 10%, 40%, and 40%, respectively, in the control group. No adverse events occurred in either group. CONCLUSION Simultaneous treatment with biologics and intra-articular injection of TA is useful for cases involving switching of biologics for RA. This strategy is safe and practical for RA treatment. PMID:27081319

Linear quadratic servo control of a reusable rocket engine

NASA Technical Reports Server (NTRS)

Musgrave, Jeffrey L.

1991-01-01

A design method for a servo compensator is developed in the frequency domain using singular values. The method is applied to a reusable rocket engine. An intelligent control system for reusable rocket engines was proposed which includes a diagnostic system, a control system, and an intelligent coordinator which determines engine control strategies based on the identified failure modes. The method provides a means of generating various linear multivariable controllers capable of meeting performance and robustness specifications and accommodating failure modes identified by the diagnostic system. Command following with set point control is necessary for engine operation. A Kalman filter reconstructs the state while loop transfer recovery recovers the required degree of robustness while maintaining satisfactory rejection of sensor noise from the command error. The approach is applied to the design of a controller for a rocket engine satisfying performance constraints in the frequency domain. Simulation results demonstrate the performance of the linear design on a nonlinear engine model over all power levels during mainstage operation.

Effect of edge pruning on structural controllability and observability of complex networks

PubMed Central

Mengiste, Simachew Abebe; Aertsen, Ad; Kumar, Arvind

2015-01-01

Controllability and observability of complex systems are vital concepts in many fields of science. The network structure of the system plays a crucial role in determining its controllability and observability. Because most naturally occurring complex systems show dynamic changes in their network connectivity, it is important to understand how perturbations in the connectivity affect the controllability of the system. To this end, we studied the control structure of different types of artificial, social and biological neuronal networks (BNN) as their connections were progressively pruned using four different pruning strategies. We show that the BNNs are more similar to scale-free networks than to small-world networks, when comparing the robustness of their control structure to structural perturbations. We introduce a new graph descriptor, ‘the cardinality curve’, to quantify the robustness of the control structure of a network to progressive edge pruning. Knowing the susceptibility of control structures to different pruning methods could help design strategies to destroy the control structures of dangerous networks such as epidemic networks. On the other hand, it could help make useful networks more resistant to edge attacks. PMID:26674854

Development of behaviour change communication strategy for a vaccination-linked malaria control tool in southern Tanzania.

PubMed

Mushi, Adiel K; Schellenberg, Joanna; Mrisho, Mwifadhi; Manzi, Fatuma; Mbuya, Conrad; Mponda, Haji; Mshinda, Hassan; Tanner, Marcel; Alonso, Pedro; Pool, Robert; Schellenberg, David

2008-09-29

Intermittent preventive treatment of malaria in infants (IPTi) using sulphadoxine-pyrimethamine and linked to the expanded programme on immunization (EPI) is a promising strategy for malaria control in young children. As evidence grows on the efficacy of IPTi as public health strategy, information is needed so that this novel control tool can be put into practice promptly, once a policy recommendation is made to implement it. This paper describes the development of a behaviour change communication strategy to support implementation of IPTi by the routine health services in southern Tanzania, in the context of a five-year research programme evaluating the community effectiveness of IPTi. Mixed methods including a rapid qualitative assessment and quantitative health facility survey were used to investigate communities' and providers' knowledge and practices relating to malaria, EPI, sulphadoxine-pyrimethamine and existing health posters. Results were applied to develop an appropriate behaviour change communication strategy for IPTi involving personal communication between mothers and health staff, supported by a brand name and two posters. Malaria in young children was considered to be a nuisance because it causes sleepless nights. Vaccination services were well accepted and their use was considered the mother's responsibility. Babies were generally taken for vaccination despite complaints about fevers and swellings after the injections. Sulphadoxine-pyrimethamine was widely used for malaria treatment and intermittent preventive treatment of malaria in pregnancy, despite widespread rumours of adverse reactions based on hearsay and newspaper reports. Almost all health providers said that they or their spouse were ready to take SP in pregnancy (96%, 223/242). A brand name, key messages and images were developed and pre-tested as behaviour change communication materials. The posters contained public health messages, which explained the intervention itself, how and when children receive it and safety issues. Implementation of IPTi started in January 2005 and evaluation is ongoing. Behaviour Change Communication (BCC) strategies for health interventions must be both culturally appropriate and technically sound. A mixed methods approach can facilitate an interactive process among relevant actors to develop a BCC strategy.

Flight path control strategies and preliminary deltaV requirements for the 2007 Mars Phoenix (PHX) mission

NASA Technical Reports Server (NTRS)

Raofi, Behzad

2005-01-01

This paper describes the methods used to estimate the statistical deltaV requirements for the propulsive maneuvers that will deliver the spacecraft to its target landing site while satisfying planetary protection requirements. the paper presents flight path control analysis results for three different trajectories, open, middle, and close of launch period for the mission.

Observer-Based Adaptive Fault-Tolerant Tracking Control of Nonlinear Nonstrict-Feedback Systems.

PubMed

Wu, Chengwei; Liu, Jianxing; Xiong, Yongyang; Wu, Ligang

2017-06-28

This paper studies an output-based adaptive fault-tolerant control problem for nonlinear systems with nonstrict-feedback form. Neural networks are utilized to identify the unknown nonlinear characteristics in the system. An observer and a general fault model are constructed to estimate the unavailable states and describe the fault, respectively. Adaptive parameters are constructed to overcome the difficulties in the design process for nonstrict-feedback systems. Meanwhile, dynamic surface control technique is introduced to avoid the problem of ''explosion of complexity''. Furthermore, based on adaptive backstepping control method, an output-based adaptive neural tracking control strategy is developed for the considered system against actuator fault, which can ensure that all the signals in the resulting closed-loop system are bounded, and the system output signal can be regulated to follow the response of the given reference signal with a small error. Finally, the simulation results are provided to validate the effectiveness of the control strategy proposed in this paper.

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

NASA Astrophysics Data System (ADS)

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

2016-08-01

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

Malaria among gold miners in southern Pará, Brazil: estimates of determinants and individual costs.

PubMed

Vosti, S A

1990-01-01

As malaria grows more prevalent in the Amazon frontier despite increased expenditures by disease control authorities, national and regional tropical disease control strategies are being called into question. The current crisis involving traditional control/eradication methods has broadened the search for feasible and effective malaria control strategies--a search that necessarily includes an investigation of the roles of a series of individual and community-level socioeconomic characteristics in determining malaria prevalence rates, and the proper methods of estimating these links. In addition, social scientists and policy makers alike know very little about the economic costs associated with malarial infections. In this paper, I use survey data from several Brazilian gold mining areas to (a) test the general reliability of malaria-related questionnaire response data, and suggest categorization methods to minimize the statistical influence of exaggerated responses, (b) estimate three statistical models aimed at detecting the socioeconomic determinants of individual malaria prevalence rates, and (c) calculate estimates of the average cost of a single bout of malaria. The results support the general reliability of survey response data gathered in conjunction with malaria research. Once the effects of vector exposure were controlled for, individual socioeconomic characteristics were only weakly linked to malaria prevalence rates in these very special miners' communities. Moreover, the socioeconomic and exposure links that were significant did not depend on the measure of malaria adopted. Finally, individual costs associated with malarial infections were found to be a significant portion of miners' incomes.

Adaptive-randomised self-calibration of electro-mechanical shutters for space imaging

NASA Astrophysics Data System (ADS)

De Cecco, Mariolino; Debei, Stefano; Zaccariotto, Mirco; Pertile, Marco

2006-11-01

This work describes the self-calibration of a high-precision open-loop mechanism. The self-calibration method is applied to a mechanical shutter for space applications, which was launched onboard the ESA-ROSETTA mission (launch: 2 March 2004). It is based on an adaptive 'model reference' and a 'randomised' search method which may be generalised to applications in which high performance and functionality are strongly interconnected. The method makes use of an adaptive 'model-reference' control approach [K.J. Astrom, B. Wittenmark, On self-tuning regulators Automatica 9 (1973) 185-199 [16]; K.J. Astrom, Theory and application of adaptive control, in: Proceedings of the Eighth IFAC World Conference, Kyoto, Japan, 1981 [17]; D.E. Seborg, S.L. Shah, T.F. Edgar, Adaptive control strategies for process control, AIChE Journal 6(32) (1986) 881-895 [18

Event-triggered synchronization for reaction-diffusion complex networks via random sampling

NASA Astrophysics Data System (ADS)

Dong, Tao; Wang, Aijuan; Zhu, Huiyun; Liao, Xiaofeng

2018-04-01

In this paper, the synchronization problem of the reaction-diffusion complex networks (RDCNs) with Dirichlet boundary conditions is considered, where the data is sampled randomly. An event-triggered controller based on the sampled data is proposed, which can reduce the number of controller and the communication load. Under this strategy, the synchronization problem of the diffusion complex network is equivalently converted to the stability of a of reaction-diffusion complex dynamical systems with time delay. By using the matrix inequality technique and Lyapunov method, the synchronization conditions of the RDCNs are derived, which are dependent on the diffusion term. Moreover, it is found the proposed control strategy can get rid of the Zeno behavior naturally. Finally, a numerical example is given to verify the obtained results.

Controlled Self-Assembly of Low-Dimensional Alq3 Nanostructures from 1D Nanowires to 2D Plates via Intermolecular Interactions

NASA Astrophysics Data System (ADS)

Gu, Jianmin; Yin, Baipeng; Fu, Shaoyan; Jin, Cuihong; Liu, Xin; Bian, Zhenpan; Li, Jianjun; Wang, Lu; Li, Xiaoyu

2018-03-01

Due to the intense influence of the shape and size of the photon building blocks on the limitation and guidance of optical waves, an important strategy is the fabrication of different structures. Herein, organic semiconductor tris-(8-hydroxyquinoline)aluminium (Alq3) nanostructures with controllable morphology, ranging from one-dimensional nanowires to two-dimensional plates, have been prepared through altering intermolecular interactions with employing the anti-solvent diffusion cooperate with solvent-volatilization induced self-assembly method. The morphologies of the formed nanostructures, which are closely related to the stacking modes of the molecules, can be exactly controlled by altering the polarity of anti-solvents that can influence various intermolecular interactions. The synthesis strategy reported here can potentially be extended to other functional organic nanomaterials.

Global stability and optimal control of epidemic spreading on multiplex networks with nonlinear mutual interaction

NASA Astrophysics Data System (ADS)

Jia, Nan; Ding, Li; Liu, Yu-Jing; Hu, Ping

2018-07-01

In this paper, we consider two interacting pathogens spreading on multiplex networks. Each pathogen spreads only on its single layer, and different layers have the same individuals but different network topology. A state-dependent infectious rate is proposed to describe the nonlinear mutual interaction during the propagation of two pathogens. Then a novel epidemic spreading model incorporating treatment control strategy is established. We investigate the global asymptotic stability of the equilibrium points by using Dulac's criterion, Poincaré-Bendixson theorem and Lyapunov method. Furthermore, we discuss an optimal strategy to minimize the total number of the infected individuals and the cost associated with treatment control for both spreading of two pathogens. Finally, numerical simulations are presented to show the validity and efficiency of our results.

Estimation of Time-Varying Pilot Model Parameters

NASA Technical Reports Server (NTRS)

Zaal, Peter M. T.; Sweet, Barbara T.

2011-01-01

Human control behavior is rarely completely stationary over time due to fatigue or loss of attention. In addition, there are many control tasks for which human operators need to adapt their control strategy to vehicle dynamics that vary in time. In previous studies on the identification of time-varying pilot control behavior wavelets were used to estimate the time-varying frequency response functions. However, the estimation of time-varying pilot model parameters was not considered. Estimating these parameters can be a valuable tool for the quantification of different aspects of human time-varying manual control. This paper presents two methods for the estimation of time-varying pilot model parameters, a two-step method using wavelets and a windowed maximum likelihood estimation method. The methods are evaluated using simulations of a closed-loop control task with time-varying pilot equalization and vehicle dynamics. Simulations are performed with and without remnant. Both methods give accurate results when no pilot remnant is present. The wavelet transform is very sensitive to measurement noise, resulting in inaccurate parameter estimates when considerable pilot remnant is present. Maximum likelihood estimation is less sensitive to pilot remnant, but cannot detect fast changes in pilot control behavior.

Current vector control challenges in the fight against malaria.

PubMed

Benelli, Giovanni; Beier, John C

2017-10-01

The effective and eco-friendly control of Anopheles vectors plays a key role in any malaria management program. Integrated Vector Management (IVM) suggests making use of the full range of vector control tools available. The strategies for IVM require novel technologies to control outdoor transmission of malaria. Despite the wide number of promising control tools tested against mosquitoes, current strategies for malaria vector control used in most African countries are not sufficient to achieve successful malaria control. The majority of National Malaria Control Programs in Africa still rely on indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs). These methods reduce malaria incidence but generally have little impact on malaria prevalence. In addition to outdoor transmission, growing levels of insecticide resistance in targeted vectors threaten the efficacy of LLINs and IRS. Larvicidal treatments can be useful, but are not recommended for rural areas. The research needed to improve the quality and delivery of mosquito vector control should focus on (i) optimization of processes and methods for vector control delivery; (ii) monitoring of vector populations and biting activity with reliable techniques; (iii) the development of effective and eco-friendly tools to reduce the burden or locally eliminate malaria and other mosquito-borne diseases; (iv) the careful evaluation of field suitability and efficacy of new mosquito control tools to prove their epidemiological impact; (v) the continuous monitoring of environmental changes which potentially affect malaria vector populations; (vi) the cooperation among different disciplines, with main emphasis on parasitology, tropical medicine, ecology, entomology, and ecotoxicology. A better understanding of behavioral ecology of malaria vectors is required. Key ecological obstacles that limit the effectiveness of vector control include the variation in mosquito behavior, development of insecticide resistance, presence of behavioral avoidance, high vector biodiversity, competitive and food web interactions, lack of insights on mosquito dispersal and mating behavior, and the impact of environmental changes on mosquito ecological traits. Overall, the trans-disciplinary cooperation among parasitologists and entomologists is crucial to ensure proper evaluation of the epidemiological impact triggered by novel mosquito vector control strategies. Copyright © 2017 Elsevier B.V. All rights reserved.

Tripartite equilibrium strategy for a carbon tax setting problem in air passenger transport.

PubMed

Xu, Jiuping; Qiu, Rui; Tao, Zhimiao; Xie, Heping

2018-03-01

Carbon emissions in air passenger transport have become increasing serious with the rapidly development of aviation industry. Combined with a tripartite equilibrium strategy, this paper proposes a multi-level multi-objective model for an air passenger transport carbon tax setting problem (CTSP) among an international organization, an airline and passengers with the fuzzy uncertainty. The proposed model is simplified to an equivalent crisp model by a weighted sum procedure and a Karush-Kuhn-Tucker (KKT) transformation method. To solve the equivalent crisp model, a fuzzy logic controlled genetic algorithm with entropy-Bolitzmann selection (FLC-GA with EBS) is designed as an integrated solution method. Then, a numerical example is provided to demonstrate the practicality and efficiency of the optimization method. Results show that the cap tax mechanism is an important part of air passenger trans'port carbon emission mitigation and thus, it should be effectively applied to air passenger transport. These results also indicate that the proposed method can provide efficient ways of mitigating carbon emissions for air passenger transport, and therefore assist decision makers in formulating relevant strategies under multiple scenarios.

Adaptive fuzzy sliding control of single-phase PV grid-connected inverter.

PubMed

Fei, Juntao; Zhu, Yunkai

2017-01-01

In this paper, an adaptive fuzzy sliding mode controller is proposed to control a two-stage single-phase photovoltaic (PV) grid-connected inverter. Two key technologies are discussed in the presented PV system. An incremental conductance method with adaptive step is adopted to track the maximum power point (MPP) by controlling the duty cycle of the controllable power switch of the boost DC-DC converter. An adaptive fuzzy sliding mode controller with an integral sliding surface is developed for the grid-connected inverter where a fuzzy system is used to approach the upper bound of the system nonlinearities. The proposed strategy has strong robustness for the sliding mode control can be designed independently and disturbances can be adaptively compensated. Simulation results of a PV grid-connected system verify the effectiveness of the proposed method, demonstrating the satisfactory robustness and performance.

The effectiveness of strategies to change organisational culture to improve healthcare performance

PubMed Central

Parmelli, Elena; Flodgren, Gerd; Schaafsma, Mary Ellen; Baillie, Nick; Beyer, Fiona R; Eccles, Martin P

2014-01-01

Background Organisational culture is an anthropological metaphor used to inform research and consultancy and to explain organisational environments. Great emphasis has been placed during the last years on the need to change organisational culture in order to pursue effective improvement of healthcare performance. However, the precise nature of organisational culture in healthcare policy often remains underspecified and the desirability and feasibility of strategies to be adopted has been called into question. Objectives To determine the effectiveness of strategies to change organisational culture in order to improve healthcare performance. To examine the effectiveness of these strategies according to different patterns of organisational culture. Search methods We searched the following electronic databases for primary studies: The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, CINAHL, Sociological Abstracts, Web of Knowledge, PsycINFO, Business and Management, EThOS, Index to Theses, Intute, HMIC, SIGLE, and Scopus until October 2009. The Database of Abstracts of Reviews of Effectiveness (DARE) was searched for related reviews. We also searched the reference lists of all papers and relevant reviews identified, and we contacted experts in the field for advice on further potential studies. Selection criteria We considered randomised controlled trials (RCTs) or well designed quasi-experimental studies, controlled clinical trials (CCTs), controlled before and after studies (CBAs) and interrupted time series analyses (ITS) meeting the quality criteria used by the Cochrane Effective Practice and Organisation of Care Group (EPOC). Studies should be set in any type of healthcare organisation in which strategies to change organisational culture in order to improve healthcare performance were applied. Our main outcomes were objective measures of professional performance and patient outcome. Data collection and analysis At least two review authors independently applied the criteria for inclusion and exclusion criteria to scan titles and abstracts and then to screen the full reports of selected citations. At each stage results were compared and discrepancies solved through discussion. Main results The search strategy yielded 4239 records. After the full text assessment, no studies met the quality criteria used by the EPOC Group and evaluated the effectiveness of strategies to change organisational culture to improve healthcare performance. Authors’ conclusions It is not possible to draw any conclusions about the effectiveness of strategies to change organisational culture because we found no studies that fulfilled the methodological criteria for this review. Research efforts should focus on strengthening the evidence about the effectiveness of methods to change organisational culture to improve health care performance. PMID:21249706

The SOBANE strategy for the management of risk, as applied to whole-body or hand-arm vibration.

PubMed

Malchaire, J; Piette, A

2006-06-01

The objective was to develop a coherent set of methods to be used effectively in industry to prevent and manage the risks associated with exposure to vibration, by coordinating the progressive intervention of the workers, their management, the occupational health and safety (OHS) professionals and the experts. The methods were developed separately for the exposure to whole-body and hand-arm vibration. The SOBANE strategy of risk prevention includes four levels of intervention: level 1, Screening; level 2, Observation; level 3, Analysis and; level 4, Expertise. The methods making it possible to apply this strategy were developed for 14 types of risk factors. The article presents the methods specific to the prevention of the risks associated with the exposure to vibration. The strategy is similar to those published for the risks associated with exposure to noise, heat and musculoskeletal disorders. It explicitly recognizes the qualifications of the workers and their management with regard to the work situation and shares the principle that measuring the exposure of the workers is not necessarily the first step in order to improve these situations. It attempts to optimize the recourse to the competences of the OHS professionals and the experts, in order to come more rapidly, effectively and economically to practical control measures.

Adding Qualitative and Mixed Methods Research to Health Intervention Studies: Interacting With Differences.

PubMed

Johnson, R Burke; Schoonenboom, Judith

2016-04-01

The purpose of this article is to explain how to improve intervention designs, such as randomized controlled trials (RCTs), in health science research using a process philosophy and theory known as dialectical pluralism (DP). DP views reality as plural and uses dialectical, dialogical, and hermeneutical approaches to knowledge construction. Using DP and its "both/and" logic, and its attempt to produce new creative syntheses, researchers on heterogeneous teams can better dialogue with qualitative and mixed methods approaches, concepts, paradigms, methodologies, and methods to improve their intervention research studies. The concept of reflexivity is utilized but is expanded when it is a component of DP. Examples of strategies for identifying, inviting, and creating divergence and integrative strategies for producing strong mixed methods intervention studies are provided and illustrated using real-life examples. © The Author(s) 2015.

Multiplexed MRM-Based Protein Quantitation Using Two Different Stable Isotope-Labeled Peptide Isotopologues for Calibration.

PubMed

LeBlanc, André; Michaud, Sarah A; Percy, Andrew J; Hardie, Darryl B; Yang, Juncong; Sinclair, Nicholas J; Proudfoot, Jillaine I; Pistawka, Adam; Smith, Derek S; Borchers, Christoph H

2017-07-07

When quantifying endogenous plasma proteins for fundamental and biomedical research - as well as for clinical applications - precise, reproducible, and robust assays are required. Targeted detection of peptides in a bottom-up strategy is the most common and precise mass spectrometry-based quantitation approach when combined with the use of stable isotope-labeled peptides. However, when measuring protein in plasma, the unknown endogenous levels prevent the implementation of the best calibration strategies, since no blank matrix is available. Consequently, several alternative calibration strategies are employed by different laboratories. In this study, these methods were compared to a new approach using two different stable isotope-labeled standard (SIS) peptide isotopologues for each endogenous peptide to be quantified, enabling an external calibration curve as well as the quality control samples to be prepared in pooled human plasma without interference from endogenous peptides. This strategy improves the analytical performance of the assay and enables the accuracy of the assay to be monitored, which can also facilitate method development and validation.

JRC GMO-Matrix: a web application to support Genetically Modified Organisms detection strategies.

PubMed

Angers-Loustau, Alexandre; Petrillo, Mauro; Bonfini, Laura; Gatto, Francesco; Rosa, Sabrina; Patak, Alexandre; Kreysa, Joachim

2014-12-30

The polymerase chain reaction (PCR) is the current state of the art technique for DNA-based detection of Genetically Modified Organisms (GMOs). A typical control strategy starts by analyzing a sample for the presence of target sequences (GM-elements) known to be present in many GMOs. Positive findings from this "screening" are then confirmed with GM (event) specific test methods. A reliable knowledge of which GMOs are detected by combinations of GM-detection methods is thus crucial to minimize the verification efforts. In this article, we describe a novel platform that links the information of two unique databases built and maintained by the European Union Reference Laboratory for Genetically Modified Food and Feed (EU-RL GMFF) at the Joint Research Centre (JRC) of the European Commission, one containing the sequence information of known GM-events and the other validated PCR-based detection and identification methods. The new platform compiles in silico determinations of the detection of a wide range of GMOs by the available detection methods using existing scripts that simulate PCR amplification and, when present, probe binding. The correctness of the information has been verified by comparing the in silico conclusions to experimental results for a subset of forty-nine GM events and six methods. The JRC GMO-Matrix is unique for its reliance on DNA sequence data and its flexibility in integrating novel GMOs and new detection methods. Users can mine the database using a set of web interfaces that thus provide a valuable support to GMO control laboratories in planning and evaluating their GMO screening strategies. The platform is accessible at http://gmo-crl.jrc.ec.europa.eu/jrcgmomatrix/ .

A Stability Enhancement Method for Centrifugal Compressors using Active Control Casing Treatment System

NASA Astrophysics Data System (ADS)

Zhao, Yuanyang; Xiao, Jun; Li, Liansheng; Yang, Qichao; Liu, Guangbin; Wang, Le

2015-08-01

The centrifugal compressors are widely used in many fields. When the centrifugal compressors operate at the edge of the surge line, the compressor will be unstable. In addition, if the centrifugal compressor runs at this situation long time, the damage will be occurred on compressor. There are some kinds of method to improve and enlarge the range of the centrifugal compressors, such as inlet guide vane, and casing treatment. For casing treatment method, some structures have been researched, such as holed recirculation, basic slot casing treatment and groove casing treatment. All these researches are the passive methods. This paper present a new stability enhancement method based Active Control Casing Treatment (ACCT). All parts of this new method are introduced in detail. The control strategy of the system is mentioned in the paper. As a research sample, a centrifugal compressor having this system is researched using CFD method. The study focuses on the effect of the active control system on the impeller flow. The vortex in impeller is changed by the active control system. And this leads to the suppression of the extension of vortex blockage in impeller and to contribute to the enhancement of the compressor operating range.