Spelling: A Visual Skill.

ERIC Educational Resources Information Center

Hendrickson, Homer

1988-01-01

Spelling problems arise due to problems with form discrimination and inadequate visualization. A child's sequence of visual development involves learning motor control and coordination, with vision directing and monitoring the movements; learning visual comparison of size, shape, directionality, and solidity; developing visual memory or recall;…

Moisture Control Guidance for Commercial and Public ...

EPA Pesticide Factsheets

This document provides guidance to designers, construction mangers, and building operation/maintenance managers to improve IEQ and reduce risks of encountering IEQ problems due to insufficient moisture control. EPA will be producing a document entitled

Early retirement and the financial assets of individuals with back problems.

PubMed

Schofield, Deborah J; Shrestha, Rupendra N; Percival, Richard; Callander, Emily J; Kelly, Simon J; Passey, Megan E

2011-05-01

This paper quantifies the relationship between early retirement due to back problems and wealth, and contributes to a more complete picture of the full costs associated with back problems. The output data set of the microsimulation model Health&WealthMOD was analysed. Health&WealthMOD was specifically designed to measure the economic impacts of ill health on Australian workers aged 45-64 years. People aged 45-64 years who are out of the labour force due to back problems have significantly less chance of having any accumulated wealth. While almost all individuals who are in full-time employment with no chronic health condition have some wealth accumulated, a significantly smaller proportion (89%) of those who have retired early due to back problems do. Of those who have retired early due to back problems who do have some wealth, on average the total value of this wealth is 87% less (95% CI: -90 to -84%) than the total value of wealth accumulated by those who have remained in full-time employment with no health condition controlling for age, sex and education. The financial burden placed on those retiring early due to back problems is likely to cause financial stress in the future, as not only have retired individuals lost an income stream from paid employment, but they also have little or no wealth to draw upon. Preventing early retirement due to back problems will increase the time individuals will have to amass savings to finance their retirement and to protect against financial shocks.

Water Pollution Control Industry

ERIC Educational Resources Information Center

Environmental Science and Technology, 1974

1974-01-01

A special report on the state of the water pollution control industry reveals that due to forthcoming federal requirements, sales and the backlogs should increase; problems may ensue because of shortages of materials and inflation. Included are reports from various individual companies. (MLB)

Application of Pesticide Phytoremediation in Irrigated Rice Fields System Using Eceng Gondok (Eichhornia crassipes) Plants

NASA Astrophysics Data System (ADS)

Febriani, Ika Kartika; Hadiyanto

2018-02-01

The problem of environmental pollution especially urban water pollution becomes major issue in Indonesia. The cause of water pollution is not only from industrial factory waste disposal but also other causes which become pollution factor. One cause of water pollution is the existence of agricultural activities with the use of the amount of pesticides that exceed the threshold. As regulated in Government Regulation No. 82/2001 on Water Quality Management and Water Pollution Control, it is necessary to manage water quality and control water pollution wisely by taking into account the interests of current and future generations as well as the ecological balance. To overcome the problem of water pollution due to agricultural activities, it is necessary to conduct research on phytoremediation technique by utilizing eceng gondok plant. It is excepted that using this phytoremediation technique can reduce the problem of water pollution due to the use of pesticides on agricultural activities.

Robust Feedback Control of Flow Induced Structural Radiation of Sound

NASA Technical Reports Server (NTRS)

Heatwole, Craig M.; Bernhard, Robert J.; Franchek, Matthew A.

1997-01-01

A significant component of the interior noise of aircraft and automobiles is a result of turbulent boundary layer excitation of the vehicular structure. In this work, active robust feedback control of the noise due to this non-predictable excitation is investigated. Both an analytical model and experimental investigations are used to determine the characteristics of the flow induced structural sound radiation problem. The problem is shown to be broadband in nature with large system uncertainties associated with the various operating conditions. Furthermore the delay associated with sound propagation is shown to restrict the use of microphone feedback. The state of the art control methodologies, IL synthesis and adaptive feedback control, are evaluated and shown to have limited success for solving this problem. A robust frequency domain controller design methodology is developed for the problem of sound radiated from turbulent flow driven plates. The control design methodology uses frequency domain sequential loop shaping techniques. System uncertainty, sound pressure level reduction performance, and actuator constraints are included in the design process. Using this design method, phase lag was added using non-minimum phase zeros such that the beneficial plant dynamics could be used. This general control approach has application to lightly damped vibration and sound radiation problems where there are high bandwidth control objectives requiring a low controller DC gain and controller order.

Design and Research of the Sewage Treatment Control System

NASA Astrophysics Data System (ADS)

Chu, J.; Hu, W. W.

Due to the rapid development of China's economy, the water pollution has become a problem that we have to face. In particular, how to deal with industrial wastewater has become a top priority. In wastewater treatment, the control system based on PLC has met the design requirement in real-time, reliability, precision and so on. The integration of sequence control and process control in PLC, has the characteristics of high reliability, simple network, convenient and flexible use. PLC is a powerful tool for small and medium-sized industrial automation. Therefore, the sewage treatment control system take PLC as the core of control system, can nicely solve the problem of industrial wastewater in a certain extent.

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.

Known TCP Implementation Problems

NASA Technical Reports Server (NTRS)

Paxson, Vern (Editor); Allman, Mark; Dawson, Scott; Fenner, William; Griner, Jim; Heavens, Ian; Lahey, K.; Semke, J.; Volz, B.

1999-01-01

This memo catalogs a number of known TCP implementation problems. The goal in doing so is to improve conditions in the existing Internet by enhancing the quality of current TCP/IP implementations. It is hoped that both performance and correctness issues can be resolved by making implementors aware of the problems and their solutions. In the long term, it is hoped that this will provide a reduction in unnecessary traffic on the network, the rate of connection failures due to protocol errors, and load on network servers due to time spent processing both unsuccessful connections and retransmitted data. This will help to ensure the stability of the global Internet. Each problem is defined as follows: Name of Problem The name associated with the problem. In this memo, the name is given as a subsection heading. Classification one or more problem categories for which the problem is classified: "congestion control", "performance", "reliability", "resource management". Description A definition of the problem, succinct but including necessary background material. Significance A brief summary of the sorts of environments for which the problem is significant.

Differentiating impacts of land use changes from pasture management in a CEAP watershed using the SWAT model

USDA-ARS?s Scientific Manuscript database

Due to intensive farm practices, nonpoint-source (NPS) pollution has become one of the most challenging environmental problems in agricultural and mixed land use watersheds. Usually, various conservation practices are implemented in the watershed to control the NPS pollution problem. However, land u...

Control and structural optimization for maneuvering large spacecraft

NASA Technical Reports Server (NTRS)

Chun, H. M.; Turner, J. D.; Yu, C. C.

1990-01-01

Presented here are the results of an advanced control design as well as a discussion of the requirements for automating both the structures and control design efforts for maneuvering a large spacecraft. The advanced control application addresses a general three dimensional slewing problem, and is applied to a large geostationary platform. The platform consists of two flexible antennas attached to the ends of a flexible truss. The control strategy involves an open-loop rigid body control profile which is derived from a nonlinear optimal control problem and provides the main control effort. A perturbation feedback control reduces the response due to the flexibility of the structure. Results are shown which demonstrate the usefulness of the approach. Software issues are considered for developing an integrated structures and control design environment.

A reinforcement sensitivity model of affective and behavioral dysregulation in marijuana use and associated problems.

PubMed

Emery, Noah N; Simons, Jeffrey S

2017-08-01

This study tested a model linking sensitivity to punishment (SP) and reward (SR) to marijuana use and problems via affect lability and poor control. A 6-month prospective design was used in a sample of 2,270 young-adults (64% female). The hypothesized SP × SR interaction did not predict affect lability or poor control, but did predict use likelihood at baseline. At low levels of SR, SP was associated with an increased likelihood of abstaining, which was attenuated as SR increased. SP and SR displayed positive main effects on both affect lability and poor control. Affect lability and poor control, in turn, mediated effects on the marijuana outcomes. Poor control predicted both increased marijuana use and, controlling for use level, greater intensity of problems. Affect lability predicted greater intensity of problems, but was not associated with use level. There were few prospective effects. SR consistently predicted greater marijuana use and problems. SP however, exhibited both risk and protective pathways. Results indicate that SP is associated with a decreased likelihood of marijuana use. However, once use is initiated SP is associated with increased risk of problems, in part, due to its effects on both affect and behavioral dysregulation. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Urea formaldehyde foam: a dangerous insulation

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

Keough, C.

1980-12-01

Insulating a home with urea formaldehyde foam can lead to severe health problems due to poisoning from formaldehyde gas. Respiratory problems, allergies, memory loss, and mental problems can result from exposure to foam insulation fumes. Research is now under way at the Chemical Industry Inst., Univ. of Washington, and other institutions to learn more about the health effects of formaldehyde foam and to develop possible remedies to these problems. Several states are either banning or controlling the use of this type of home insulation.

On Complete Control and Synchronization of Zhang Chaotic System with Uncertain Parameters using Adaptive Control Method

NASA Astrophysics Data System (ADS)

Tirandaz, Hamed

2018-03-01

Chaos control and synchronization of chaotic systems is seemingly a challenging problem and has got a lot of attention in recent years due to its numerous applications in science and industry. This paper concentrates on the control and synchronization problem of the three-dimensional (3D) Zhang chaotic system. At first, an adaptive control law and a parameter estimation law are achieved for controlling the behavior of the Zhang chaotic system. Then, non-identical synchronization of Zhang chaotic system is provided with considering the Lü chaotic system as the follower system. The synchronization problem and parameters identification are achieved by introducing an adaptive control law and a parameters estimation law. Stability analysis of the proposed method is proved by the Lyapanov stability theorem. In addition, the convergence of the estimated parameters to their truly unknown values are evaluated. Finally, some numerical simulations are carried out to illustrate and to validate the effectiveness of the suggested method.

Ascent control studies of the 049 and ATP parallel burn solid rocket motor shuttle configurations

NASA Technical Reports Server (NTRS)

Ryan, R. S.; Mowery, D. K.; Hammer, M.; Weisler, A. C.

1972-01-01

The control authority approach is discussed as a major problem of the parallel burn soil shuttle configuration due to the many resulting system impacts regardless of the approach. The major trade studies and their results, which led to the recommendation of an SRB TVC control authority approach are presented.

A method of measuring increase in soil depth and water-storage capacity due to forest management

Treesearch

George R., Jr. Trimble

1952-01-01

Conservationists, engineers, and others who deal with water problems have become more and more concerned in recent years with increasing the storage of water in the ground. Their concern has centered around problems of flood control and storage of water for later use by plants or animals, including man.

Rotordynamic Instability Problems in High-Performance Turbomachinery

NASA Technical Reports Server (NTRS)

1980-01-01

Diagnostic and remedial methods concerning rotordynamic instability problems in high performance turbomachinery are discussed. Instabilities due to seal forces and work-fluid forces are identified along with those induced by rotor bearing systems. Several methods of rotordynamic control are described including active feedback methods, the use of elastometric elements, and the use of hydrodynamic journal bearings and supports.

Offspring ADHD as a risk factor for parental marital problems: controls for genetic and environmental confounds.

PubMed

Schermerhorn, Alice C; D'Onofrio, Brian M; Slutske, Wendy S; Emery, Robert E; Turkheimer, Eric; Harden, K Paige; Heath, Andrew C; Martin, Nicholas G

2012-12-01

Previous studies have found that child attention-deficit/hyperactivity disorder (ADHD) is associated with more parental marital problems. However, the reasons for this association are unclear. The association might be due to genetic or environmental confounds that contribute to both marital problems and ADHD. Data were drawn from the Australian Twin Registry, including 1,296 individual twins, their spouses, and offspring. We studied adult twins who were discordant for offspring ADHD.Using a discordant twin pairs design, we examined the extent to which genetic and environmental confounds,as well as measured parental and offspring characteristics, explain the ADHD-marital problems association. Offspring ADHD predicted parental divorce and marital conflict. The associations were also robust when comparing differentially exposed identical twins to control for unmeasured genetic and environmental factors, when controlling for measured maternal and paternal psychopathology,when restricting the sample based on timing of parental divorce and ADHD onset, and when controlling for other forms of offspring psychopathology. Each of these controls rules out alternative explanations for the association. The results of the current study converge with those of prior research in suggesting that factors directly associated with offspring ADHD increase parental marital problems.

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.

Offspring ADHD as a Risk Factor for Parental Marital Problems: Controls for Genetic and Environmental Confounds

PubMed Central

Schermerhorn, Alice C.; D’Onofrio, Brian M.; Slutske, Wendy S.; Emery, Robert E.; Turkheimer, Eric; Harden, K. Paige; Heath, Andrew C.; Martin, Nicholas G.

2013-01-01

Background Previous studies have found that child attention-deficit/hyperactivity disorder (ADHD) is associated with more parental marital problems. The reasons for this association are unclear, however. The association might be due to genetic or environmental confounds that contribute to both marital problems and ADHD. Method Data were drawn from the Australian Twin Registry, including 1296 individual twins, their spouses, and offspring. We studied adult twins who were discordant for offspring ADHD. Using a discordant twin pairs design, we examined the extent to which genetic and environmental confounds, as well as measured parental and offspring characteristics, explain the ADHD-marital problems association. Results Offspring ADHD predicted parental divorce and marital conflict. The associations were also robust when comparing differentially exposed identical twins to control for unmeasured genetic and environmental factors, when controlling for measured maternal and paternal psychopathology, when restricting the sample based on timing of parental divorce and ADHD onset, and when controlling for other forms of offspring psychopathology. Each of these controls rules out alternative explanations for the association. Conclusion The results of the current study converge with those of prior research in suggesting that factors directly associated with offspring ADHD increase parental marital problems. PMID:22958575

Application of oil spill model to marine pollution and risk control problems

NASA Astrophysics Data System (ADS)

Aseev, Nikita; Agoshkov, Valery; Sheloput, Tatyana

2017-04-01

Oil transportation by sea induces challenging problems of environmental control. Millions of tonnes of oil are yearly released during routine ship operations, not to mention vast spills due to different accidents (e.g. tanker collisions, grounding, etc.). Oil pollution is dangerous to marine organisms such as plants, fish and mammals, leading to widespread damage to our planet. In turn, fishery and travel agencies can lose money and clients, and ship operators are obliged to pay huge penalties for environmental pollution. In this work we present the method of accessing oil pollution of marine environment using recently developed oil spill model. The model describes basic processes of the oil slick evolution: oil transport due to currents, drift under the action of wind, spreading on the surface, evaporation, emulsification and dispersion. Such parameters as slick location, mass, density of oil, water content, viscosity and density of "water-in-oil" emulsion can be calculated. We demonstrate how to apply the model to damage calculation problems using a concept of average damage to particular marine area. We also formulate the problem of oil spill risk control, when some accident parameters are not known, but their probability distribution is given. We propose a new algorithm to solve such problems and show results of our model simulations. The work can be interesting to broad environmental, physics and mathematics community. The work is supported by Russian Foundation for Basic Research grant 16-31-00510.

Behaviour planning and problem solving deficiencies in children with symptoms of attention deficit hyperactivity disorder from the Balobedu culture, Limpopo province, South Africa.

PubMed

Pila-Nemutandani, Refilwe Gloria; Meyer, Anneke

2016-07-01

To compare planning behaviour (frontal lobe functioning) in children with and without symptoms of attention deficit hyperactivity disorder (ADHD). A total of 90 children (45 with symptoms of ADHD and 45 matched controls without ADHD symptoms) of both genders, who were medication naïve, from the Balobedu culture (Limpopo province, South Africa), aged 7-13 years, participated in the study. The performance of the two groups was compared on a test of planning and problem solving, the Tower of London (ToL) task. The results were analysed as a function of gender and ADHD subtype. The Finger Tapping test (testing fine motor skills) was used as a control test to verify that the expected differences were not due to poor motor skills. The children with ADHD symptoms scored significantly lower than the non-ADHD comparison group which indicated deficiency in frontal lobe functioning (p = 0.00). The difference in performance was not due to poor motor control (p = 0.70). Children with ADHD symptoms show deficits in behavioural planning which indicates impairment of functions of the frontal areas supplied by the mesocortical dopamine branch. More so than others, the ADHD Inattentive and Combined subtypes showed poor performance in the Tower of London task, indicating poor organisational and planning skills in these groups. The results also did show that the difference was not due to problems with motor control and that the ToL task is a culture-fair instrument for testing planning behaviour.

Optimal Control of Distributed Energy Resources using Model Predictive Control

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

Mayhorn, Ebony T.; Kalsi, Karanjit; Elizondo, Marcelo A.

2012-07-22

In an isolated power system (rural microgrid), Distributed Energy Resources (DERs) such as renewable energy resources (wind, solar), energy storage and demand response can be used to complement fossil fueled generators. The uncertainty and variability due to high penetration of wind makes reliable system operations and controls challenging. In this paper, an optimal control strategy is proposed to coordinate energy storage and diesel generators to maximize wind penetration while maintaining system economics and normal operation. The problem is formulated as a multi-objective optimization problem with the goals of minimizing fuel costs and changes in power output of diesel generators, minimizingmore » costs associated with low battery life of energy storage and maintaining system frequency at the nominal operating value. Two control modes are considered for controlling the energy storage to compensate either net load variability or wind variability. Model predictive control (MPC) is used to solve the aforementioned problem and the performance is compared to an open-loop look-ahead dispatch problem. Simulation studies using high and low wind profiles, as well as, different MPC prediction horizons demonstrate the efficacy of the closed-loop MPC in compensating for uncertainties in wind and demand.« less

Nonlinear Dynamic Model-Based Multiobjective Sensor Network Design Algorithm for a Plant with an Estimator-Based Control System

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

Paul, Prokash; Bhattacharyya, Debangsu; Turton, Richard

Here, a novel sensor network design (SND) algorithm is developed for maximizing process efficiency while minimizing sensor network cost for a nonlinear dynamic process with an estimator-based control system. The multiobjective optimization problem is solved following a lexicographic approach where the process efficiency is maximized first followed by minimization of the sensor network cost. The partial net present value, which combines the capital cost due to the sensor network and the operating cost due to deviation from the optimal efficiency, is proposed as an alternative objective. The unscented Kalman filter is considered as the nonlinear estimator. The large-scale combinatorial optimizationmore » problem is solved using a genetic algorithm. The developed SND algorithm is applied to an acid gas removal (AGR) unit as part of an integrated gasification combined cycle (IGCC) power plant with CO 2 capture. Due to the computational expense, a reduced order nonlinear model of the AGR process is identified and parallel computation is performed during implementation.« less

Nonlinear Dynamic Model-Based Multiobjective Sensor Network Design Algorithm for a Plant with an Estimator-Based Control System

DOE PAGES

Paul, Prokash; Bhattacharyya, Debangsu; Turton, Richard; ...

2017-06-06

Here, a novel sensor network design (SND) algorithm is developed for maximizing process efficiency while minimizing sensor network cost for a nonlinear dynamic process with an estimator-based control system. The multiobjective optimization problem is solved following a lexicographic approach where the process efficiency is maximized first followed by minimization of the sensor network cost. The partial net present value, which combines the capital cost due to the sensor network and the operating cost due to deviation from the optimal efficiency, is proposed as an alternative objective. The unscented Kalman filter is considered as the nonlinear estimator. The large-scale combinatorial optimizationmore » problem is solved using a genetic algorithm. The developed SND algorithm is applied to an acid gas removal (AGR) unit as part of an integrated gasification combined cycle (IGCC) power plant with CO 2 capture. Due to the computational expense, a reduced order nonlinear model of the AGR process is identified and parallel computation is performed during implementation.« less

Factors associated with adult poisoning in northern Malaysia: a case-control study.

PubMed

Fathelrahman, A I; Ab Rahman, A F; Zain, Z Mohd; Tengku, M A

2006-04-01

Data on adult risk factors associated with drug or chemical poisonings in Malaysia are scarce. The objective of the study was to identify possible risk factors associated with adult admissions to the Penang General Hospital (PGH) due to chemical poisoning and/or drug overdose. The present study was a case-control study, conducted over 18 weeks. One hundred acutely poisoned adult patients admitted to PGH during the period from September 2003 to February 2004 were considered as cases. Two hundred patients admitted to the same medical wards for other illnesses, during the same period, were matched for age and gender with the poisoned cases and thus selected as controls. McNemar test and binary logistic were used for univariate analysis and logistic regression analysis for multivariate analyses. The odds ratio (OR) and its 95% confidence interval (95% CI) were calculated for each predictor variable. Positive histories of psychiatric illness and previous poisoning, problems in boy/girl friend relationships, family problems, marital problems, Indian ethnicity, Chinese ethnicity, living in rented houses and living in a household with less than five people were significant risk factors associated with adult admissions due to poisoning.

Nonlinear robust control of hypersonic aircrafts with interactions between flight dynamics and propulsion systems.

PubMed

Li, Zhaoying; Zhou, Wenjie; Liu, Hao

2016-09-01

This paper addresses the nonlinear robust tracking controller design problem for hypersonic vehicles. This problem is challenging due to strong coupling between the aerodynamics and the propulsion system, and the uncertainties involved in the vehicle dynamics including parametric uncertainties, unmodeled model uncertainties, and external disturbances. By utilizing the feedback linearization technique, a linear tracking error system is established with prescribed references. For the linear model, a robust controller is proposed based on the signal compensation theory to guarantee that the tracking error dynamics is robustly stable. Numerical simulation results are given to show the advantages of the proposed nonlinear robust control method, compared to the robust loop-shaping control approach. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Robust energy-absorbing compensators for the ACTEX II test article

NASA Astrophysics Data System (ADS)

Blaurock, Carl A.; Miller, David W.; Nye, Ted

1995-05-01

The paper addresses the problem of satellite solar panel vibration. A multi-layer vibration control scheme is investigated using a flight test article. Key issues in the active control portion are presented in the paper. The paper discusses the primary control design drivers, which are the time variations in modal frequencies due to configuration and thermal changes. A local control design approach is investigated, but found to be unworkable due to sensor/actuator non-collocation. An alternate design process uses linear robust control techniques, by describing the modal shifts as uncertainties. Multiple modal design, alpha- shifted multiple model, and a feedthrough compensation scheme are examined. Ground and simulation tests demonstrate that the resulting controllers provide significant vibration reduction in the presence of expected system variations.

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.

Control and instanton trajectories for random transitions in turbulent flows

NASA Astrophysics Data System (ADS)

Bouchet, Freddy; Laurie, Jason; Zaboronski, Oleg

2011-12-01

Many turbulent systems exhibit random switches between qualitatively different attractors. The transition between these bistable states is often an extremely rare event, that can not be computed through DNS, due to complexity limitations. We present results for the calculation of instanton trajectories (a control problem) between non-equilibrium stationary states (attractors) in the 2D stochastic Navier-Stokes equations. By representing the transition probability between two states using a path integral formulation, we can compute the most probable trajectory (instanton) joining two non-equilibrium stationary states. Technically, this is equivalent to the minimization of an action, which can be related to a fluid mechanics control problem.

Motion and force control of multiple robotic manipulators

NASA Technical Reports Server (NTRS)

Wen, John T.; Kreutz-Delgado, Kenneth

1992-01-01

This paper addresses the motion and force control problem of multiple robot arms manipulating a cooperatively held object. A general control paradigm is introduced which decouples the motion and force control problems. For motion control, different control strategies are constructed based on the variables used as the control input in the controller design. There are three natural choices; acceleration of a generalized coordinate, arm tip force vectors, and the joint torques. The first two choices require full model information but produce simple models for the control design problem. The last choice results in a class of relatively model independent control laws by exploiting the Hamiltonian structure of the open loop system. The motion control only determines the joint torque to within a manifold, due to the multiple-arm kinematic constraint. To resolve the nonuniqueness of the joint torques, two methods are introduced. If the arm and object models are available, an optimization can be performed to best allocate the desired and effector control force to the joint actuators. The other possibility is to control the internal force about some set point. It is shown that effective force regulation can be achieved even if little model information is available.

A novel robust speed controller scheme for PMBLDC motor.

PubMed

Thirusakthimurugan, P; Dananjayan, P

2007-10-01

The design of speed and position controllers for permanent magnet brushless DC motor (PMBLDC) drive remains as an open problem in the field of motor drives. A precise speed control of PMBLDC motor is complex due to nonlinear coupling between winding currents and rotor speed. In addition, the nonlinearity present in the developed torque due to magnetic saturation of the rotor further complicates this issue. This paper presents a novel control scheme to the conventional PMBLDC motor drive, which aims at improving the robustness by complete decoupling of the design besides minimizing the mutual influence among the speed and current control loops. The interesting feature of this robust control scheme is its suitability for both static and dynamic aspects. The effectiveness of the proposed robust speed control scheme is verified through simulations.

Air Traffic Control: Economics of Flight

NASA Technical Reports Server (NTRS)

Murphy, James R.

2004-01-01

Contents include the following: 1. Commercial flight is a partnership. Airlines. Pilots. Air traffic control. 2. Airline schedules and weather problems can cause delays at the airport. Delays are inevitable in de-regulated industry due to simple economics. 3.Delays can be mitigated. Build more runways/technology. Increase airspace supply. 4. Cost/benefit analysis determine justification.

Frequency Domain Design of Robust Controllers for Space Structures

DTIC Science & Technology

1989-08-01

A natural assumption for structural problems [1] is that A0 is self -adjoint with compact resolvent and discrete (real) spectrum which is bounded from...the same controller using only 256 points. The curves are very similiar, but in both cases, the low frequency end of the respose is under-sampled due

Design And Implementation Of PID Controller Using Relay Feedback On TRMS (Twin Rotor MIMO System)

NASA Astrophysics Data System (ADS)

Shah, Dipesh H.

2011-12-01

Today, many process control problems can be adequately and routinely solved by conventional PID control strategies. The overriding reason that the PID controller is so widely accepted is its simple structure which has proved to be very robust with regard to many commonly met process control problems as for instance disturbances and nonlinearities. Relay feedback methods have been widely used in tuning proportional-integral-derivative controllers due to its closed loop nature. In this work, Relay based PID controller is designed and successfully implemented on TRMS (Twin Rotor MIMO System) in SISO and MIMO configurations. The performance of a Relay based PID controller for control of TRMS is investigated and performed satisfactorily. The system shares some features with a helicopter, such as important interactions between the vertical and horizontal motions. The RTWT toolbox in the MATLAB environment is used to perform real-time experiments.

Spillover, nonlinearity, and flexible structures

NASA Technical Reports Server (NTRS)

Bass, Robert W.; Zes, Dean

1991-01-01

Many systems whose evolution in time is governed by Partial Differential Equations (PDEs) are linearized around a known equilibrium before Computer Aided Control Engineering (CACE) is considered. In this case, there are infinitely many independent vibrational modes, and it is intuitively evident on physical grounds that infinitely many actuators would be needed in order to control all modes. A more precise, general formulation of this grave difficulty (spillover problem) is due to A.V. Balakrishnan. A possible route to circumvention of this difficulty lies in leaving the PDE in its original nonlinear form, and adding the essentially finite dimensional control action prior to linearization. One possibly applicable technique is the Liapunov Schmidt rigorous reduction of singular infinite dimensional implicit function problems to finite dimensional implicit function problems. Omitting details of Banach space rigor, the formalities of this approach are given.

Suspended Education in Massachusetts: Using Days of Lost Instruction Due to Suspension to Evaluate Our Schools

ERIC Educational Resources Information Center

Losen, Daniel J.; Sun, Wei-Ling; Keith, Michael A., II

2017-01-01

Missed instruction can have a devastating impact on educational outcomes. Some reasons for missed instruction are beyond the control of schools and districts: some students miss school due to mental or physical illness or injury, and transportation problems sometimes are to blame. One major reason for missed instruction that schools can directly…

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

NASA Astrophysics Data System (ADS)

Kunisetti, V. Praveen Kumar; Thippiripati, Vinay Kumar

2018-01-01

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

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

NASA Astrophysics Data System (ADS)

Kunisetti, V. Praveen Kumar; Thippiripati, Vinay Kumar

2018-06-01

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

Dynamic characteristics of triaxial active control magnetic bearing with asymmetric structure

NASA Astrophysics Data System (ADS)

Nakajima, Atsushi; Hirata, Katsuhiro; Niguchi, Noboru; Kato, Masayuki

2018-03-01

Supporting forces of magnetic bearings are lower than those of mechanical bearings. In order to solve these problems, this paper proposes a new three-axis active control magnetic bearing (3-axis AMB) with an asymmetric structure where its rotor is attracted only in one axial direction due to a negative pressure of fluid. Our proposed 3-axis AMB can generate a large suspension force in one axial direction due to the asymmetric structure. The performances of our proposed 3-axis AMB are computed through 3-D finite element analysis.

The Right to Regulate

NASA Technical Reports Server (NTRS)

Vittek, J. F.

1972-01-01

An introduction to the historical and constitutional framework of industry regulation by local and Federal Governments is presented. Problems of the confiscation of private property without due process, government control and the rights and duties of the regulated industry are discussed.

Elimination of Mental Defect Due to Iodine Deficiency by the Year 2000.

ERIC Educational Resources Information Center

Hetzel, Basil S.

1993-01-01

This paper reviews the effects of iodine deficiency across the lifespan, with special reference to mental defect; discusses the magnitude of the problem; describes available iodine technology to control iodine deficiency disorders (IDD); and notes the status of national IDD control programs, to assess the likelihood of eliminating IDD by the year…

A receding horizon sliding control approach for electric powertrains with backlash and flexible half-shafts

NASA Astrophysics Data System (ADS)

Li, Yutong; Hansen, Andreas; Karl Hedrick, J.; Zhang, Junzhi

2017-12-01

Active control of electric powertrains is challenging, due to the fact that backlash and structural flexibility in transmission components can cause severe performance degradation or even instability of the control system. Furthermore, high impact forces in transmissions reduce driving comfort and possibly lead to damage of the mechanical elements in contact. In this paper, a nonlinear electric powertrain is modelled as a piecewise affine (PWA) system. The novel receding horizon sliding control (RHSC) idea is extended to constrained PWA systems and utilised to systematically address the active control problem for electric powertrains. Simulations are conducted in Matlab/Simulink in conjunction with the high fidelity Carsim software. RHSC shows superior jerk suppression and target wheel speed tracking performance as well as reduced computational cost over classical model predictive control (MPC). This indicates the newly proposed RHSC is an effective method to address the active control problem for electric powertrains.

Sleep Problems, Comorbid Mental Disorders, and Role Functioning in the National Comorbidity Survey Replication (NCS-R)

PubMed Central

Roth, Thomas; Jaeger, Savina; Jin, Robert; Kalsekar, Anupama; Stang, Paul E.; Kessler, Ronald C.

2007-01-01

Background Little is known about the population prevalence of sleep problems or whether the associations of sleep problems with role impairment are due to comorbid mental disorders. Methods The associations of four 12-month sleep problems (difficulty initiating or maintaining sleep, early morning awakening, nonrestorative sleep) with role impairment were analyzed in the National Comorbidity Survey Replication controlling 12-month DSM-IV anxiety, mood, impulse-control, and substance disorders. The WHO Composite International Diagnostic Interview was used to assess sleep problems and DSM-IV disorders. The WHO Disability Schedule-II (WHO-DAS) was used to assess role impairment. Results Prevalence estimates of the separate sleep problems were in the range 16.4-25.0%, with 36.3% reporting at least one of the four. Mean 12-month duration was 24.4 weeks. All four problems were significantly comorbid with all the 12-month DMS-IV disorders assessed in the survey (median OR: 3.4; 25th-75th percentile: 2.8-3.9) and significantly related to role impairment. Relationships with role impairment generally remained significant after controlling comorbid mental disorders. Nonrestorative sleep was more strongly and consistently related to role impairment than were the other sleep problems. Conclusions The four sleep problems considered here are of public health significance because of their high prevalence and significant associations with role impairment. PMID:16952333

A comparison of the effects of exercises plus connective tissue massage to exercises alone in women with fibromyalgia syndrome: a randomized controlled trial.

PubMed

Toprak Celenay, Seyda; Anaforoglu Kulunkoglu, Bahar; Yasa, Mustafa Ertugrul; Sahbaz Pirincci, Cansu; Un Yildirim, Necmiye; Kucuksahin, Orhan; Ugurlu, Fatma Gulcin; Akkus, Selami

2017-11-01

This study aimed to compare the effectiveness of a 6-week combined exercise program with and without connective tissue massage (CTM) on pain, fatigue, sleep problem, health status, and quality of life in patients with fibromyalgia syndrome (FMS). Patients were randomly allocated into Exercise (n = 20) and Exercise + CTM (n = 20) groups. The exercise program with and without CTM was carried out 2 days a week for 6 weeks. Pain, fatigue, sleep problem with Visual Analog Scales, health status with Fibromyalgia Impact Questionnaire (FIQ), and quality of life with Short Form-36 were evaluated. After the program, pain, fatigue and sleep problem reduced, health status (except of the scores of FIQ-1 and FIQ-10), physical functioning, role limitations due to physical health, bodily pain, role limitations due to emotional health, vitality, and general health perceptions parameters related to quality of life improved in the Exercise group, (P < 0.05). In the Exercise + CTM group, pain, fatigue and sleep problem decreased, health status and quality of life improved (P < 0.05). Pain, fatigue, sleep problem, and role limitations due to physical health improved in the Exercise + CTM group in comparison to the Exercise group (P < 0.05). The study suggested that exercises with and without CTM might be effective for decreasing pain, fatigue and sleep problem whereas increasing health status and quality of life in patients with FMS. However, exercises with CTM might be superior in improving pain, fatigue, sleep problem, and role limitations due to physical health compared to exercise alone.

Numerical Analysis on Seepage in the deep overburden CFRD

NASA Astrophysics Data System (ADS)

Zeyu, GUO; Junrui, CHAI; Yuan, QIN

2017-12-01

There are many problems in the construction of hydraulic structures on deep overburden because of its complex foundation structure and poor geological condition. Seepage failure is one of the main problems. The Combination of the seepage control system of the face rockfill dam and the deep overburden can effectively control the seepage of construction of the concrete face rockfill dam on the deep overburden. Widely used anti-seepage measures are horizontal blanket, waterproof wall, curtain grouting and so on, but the method, technique and its effect of seepage control still have many problems thus need further study. Due to the above considerations, Three-dimensional seepage field numerical analysis based on practical engineering case is conducted to study the seepage prevention effect under different seepage prevention methods, which is of great significance to the development of dam technology and the development of hydropower resources in China.

Model Predictive Control-based Optimal Coordination of Distributed Energy Resources

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

Mayhorn, Ebony T.; Kalsi, Karanjit; Lian, Jianming

2013-01-07

Distributed energy resources, such as renewable energy resources (wind, solar), energy storage and demand response, can be used to complement conventional generators. The uncertainty and variability due to high penetration of wind makes reliable system operations and controls challenging, especially in isolated systems. In this paper, an optimal control strategy is proposed to coordinate energy storage and diesel generators to maximize wind penetration while maintaining system economics and normal operation performance. The goals of the optimization problem are to minimize fuel costs and maximize the utilization of wind while considering equipment life of generators and energy storage. Model predictive controlmore » (MPC) is used to solve a look-ahead dispatch optimization problem and the performance is compared to an open loop look-ahead dispatch problem. Simulation studies are performed to demonstrate the efficacy of the closed loop MPC in compensating for uncertainties and variability caused in the system.« less

Model Predictive Control-based Optimal Coordination of Distributed Energy Resources

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

Mayhorn, Ebony T.; Kalsi, Karanjit; Lian, Jianming

2013-04-03

Distributed energy resources, such as renewable energy resources (wind, solar), energy storage and demand response, can be used to complement conventional generators. The uncertainty and variability due to high penetration of wind makes reliable system operations and controls challenging, especially in isolated systems. In this paper, an optimal control strategy is proposed to coordinate energy storage and diesel generators to maximize wind penetration while maintaining system economics and normal operation performance. The goals of the optimization problem are to minimize fuel costs and maximize the utilization of wind while considering equipment life of generators and energy storage. Model predictive controlmore » (MPC) is used to solve a look-ahead dispatch optimization problem and the performance is compared to an open loop look-ahead dispatch problem. Simulation studies are performed to demonstrate the efficacy of the closed loop MPC in compensating for uncertainties and variability caused in the system.« less

Vaccination and treatment as control interventions in an infectious disease model with their cost optimization

NASA Astrophysics Data System (ADS)

Kumar, Anuj; Srivastava, Prashant K.

2017-03-01

In this work, an optimal control problem with vaccination and treatment as control policies is proposed and analysed for an SVIR model. We choose vaccination and treatment as control policies because both these interventions have their own practical advantage and ease in implementation. Also, they are widely applied to control or curtail a disease. The corresponding total cost incurred is considered as weighted combination of costs because of opportunity loss due to infected individuals and costs incurred in providing vaccination and treatment. The existence of optimal control paths for the problem is established and guaranteed. Further, these optimal paths are obtained analytically using Pontryagin's Maximum Principle. We analyse our results numerically to compare three important strategies of proposed controls, viz.: vaccination only; with both treatment and vaccination; and treatment only. We note that first strategy (vaccination only) is less effective as well as expensive. Though, for a highly effective vaccine, vaccination alone may also work well in comparison with treatment only strategy. Among all the strategies, we observe that implementation of both treatment and vaccination is most effective and less expensive. Moreover, in this case the infective population is found to be relatively very low. Thus, we conclude that the comprehensive effect of vaccination and treatment not only minimizes cost burden due to opportunity loss and applied control policies but also keeps a tab on infective population.

A Fundamental Mathematical Model of a Microbial Predenitrification System

NASA Technical Reports Server (NTRS)

Hoo, Karlene A.

2005-01-01

Space flight beyond Low Earth Orbit requires sophisticated systems to support all aspects of the mission (life support, real-time communications, etc.). A common concern that cuts across all these systems is the selection of information technology (IT) methodology, software and hardware architectures to provide robust monitoring, diagnosis, and control support. Another dimension of the problem space is that different systems must be integrated seamlessly so that communication speed and data handling appear as a continuum (un-interrupted). One such team investigating this problem is the Advanced Integration Matrix (AIM) team whose role is to define the critical requirements expected of software and hardware to support an integrated approach to the command and control of Advanced Life Support (ALS) for future long-duration human space missions, including permanent human presence on the Moon and Mars. A goal of the AIM team is to set the foundation for testing criteria that will assist in specifying tasks, control schemes and test scenarios to validate and verify systems capabilities. This project is to contribute to the goals of the AIM team by assisting with controls planning for ALS. Control for ALS is an enormous problem it involves air revitalization, water recovery, food production, solids processing and crew. In more general terms, these systems can be characterized as involving both continuous and discrete processes, dynamic interactions among the sub-systems, nonlinear behavior due to the complex operations, and a large number of multivariable interactions due to the dimension of the state space. It is imperative that a baseline approach from which to measure performance is established especially when the expectation for the control system is complete autonomous control.

Neural networks for continuous online learning and control.

PubMed

Choy, Min Chee; Srinivasan, Dipti; Cheu, Ruey Long

2006-11-01

This paper proposes a new hybrid neural network (NN) model that employs a multistage online learning process to solve the distributed control problem with an infinite horizon. Various techniques such as reinforcement learning and evolutionary algorithm are used to design the multistage online learning process. For this paper, the infinite horizon distributed control problem is implemented in the form of real-time distributed traffic signal control for intersections in a large-scale traffic network. The hybrid neural network model is used to design each of the local traffic signal controllers at the respective intersections. As the state of the traffic network changes due to random fluctuation of traffic volumes, the NN-based local controllers will need to adapt to the changing dynamics in order to provide effective traffic signal control and to prevent the traffic network from becoming overcongested. Such a problem is especially challenging if the local controllers are used for an infinite horizon problem where online learning has to take place continuously once the controllers are implemented into the traffic network. A comprehensive simulation model of a section of the Central Business District (CBD) of Singapore has been developed using PARAMICS microscopic simulation program. As the complexity of the simulation increases, results show that the hybrid NN model provides significant improvement in traffic conditions when evaluated against an existing traffic signal control algorithm as well as a new, continuously updated simultaneous perturbation stochastic approximation-based neural network (SPSA-NN). Using the hybrid NN model, the total mean delay of each vehicle has been reduced by 78% and the total mean stoppage time of each vehicle has been reduced by 84% compared to the existing traffic signal control algorithm. This shows the efficacy of the hybrid NN model in solving large-scale traffic signal control problem in a distributed manner. Also, it indicates the possibility of using the hybrid NN model for other applications that are similar in nature as the infinite horizon distributed control problem.

Field evaluation of hydromulches for water quality and vegetation establishment.

DOT National Transportation Integrated Search

2013-03-01

Soil erosion and sediment pollution can be major problems in and around construction sites due to land disturbing activities that leave areas of : unprotected soil during active construction. Establishing vegetation to control erosion can be difficul...

Target Capturing Control for Space Robots with Unknown Mass Properties: A Self-Tuning Method Based on Gyros and Cameras.

PubMed

Li, Zhenyu; Wang, Bin; Liu, Hong

2016-08-30

Satellite capturing with free-floating space robots is still a challenging task due to the non-fixed base and unknown mass property issues. In this paper gyro and eye-in-hand camera data are adopted as an alternative choice for solving this problem. For this improved system, a new modeling approach that reduces the complexity of system control and identification is proposed. With the newly developed model, the space robot is equivalent to a ground-fixed manipulator system. Accordingly, a self-tuning control scheme is applied to handle such a control problem including unknown parameters. To determine the controller parameters, an estimator is designed based on the least-squares technique for identifying the unknown mass properties in real time. The proposed method is tested with a credible 3-dimensional ground verification experimental system, and the experimental results confirm the effectiveness of the proposed control scheme.

Target Capturing Control for Space Robots with Unknown Mass Properties: A Self-Tuning Method Based on Gyros and Cameras

PubMed Central

Li, Zhenyu; Wang, Bin; Liu, Hong

2016-01-01

Satellite capturing with free-floating space robots is still a challenging task due to the non-fixed base and unknown mass property issues. In this paper gyro and eye-in-hand camera data are adopted as an alternative choice for solving this problem. For this improved system, a new modeling approach that reduces the complexity of system control and identification is proposed. With the newly developed model, the space robot is equivalent to a ground-fixed manipulator system. Accordingly, a self-tuning control scheme is applied to handle such a control problem including unknown parameters. To determine the controller parameters, an estimator is designed based on the least-squares technique for identifying the unknown mass properties in real time. The proposed method is tested with a credible 3-dimensional ground verification experimental system, and the experimental results confirm the effectiveness of the proposed control scheme. PMID:27589748

Association Study of HLA-DQB1*0602 Allele in Iranian Patients with Narcolepsy.

PubMed

Geremew, Demeke; Rahimi-Golkhandan, Ania; Sadeghniiat-Haghighi, Khosro; Shakiba, Yadollah; Khajeh-Mehrizi, Ahmad; Ansaripour, Bita; Izad, Maryam

2017-10-01

Narcolepsy is a rare, disabling disorder characterized by excessive daytime sleepiness, cataplexy, hypnagogic hallucinations and sleep paralysis. Several studies demonstrated its association with HLA-DQB1*0602 in various ethnic groups. Our study aimed to determine the prevalence of HLA-DQB1*0602 allele in Iranian patients with narcolepsy and assess its predictive parameters for diagnosing narcolepsy. In addition, car accidents and job problems were assessed among narcoleptic patients. We studied 44 narcoleptic patients, 30 patients with other types of excessive daytime sleepiness (EDS)  and 50 healthy age and sex matched individuals in this case-control study. Patients and controls filled out a questionnaire including items about car accidents due to sleepiness and job problems. International classification of sleep disorders-2 criteria was used as the gold standard for diagnosis of narcolepsy. The DNAs isolated from whole blood samples were collected from the patients and controls to assess the presence of HLA-DQB1*0602. The results showed that HLA DQB1*0602 was present in 4 (8%) individual of controls and 20 (45.5%) patients with higher prevalence in patients with cataplexy (78.9%) than patients without cataplexy (p<0.001). The sensitivities of the DQB1*0602 for diagnosing narcolepsy with cataplexy and narcolepsy without cataplexy were 78.9 and 20; specificities were 88 and 72.4, respectively. 18.2% of patients had car accidents due to sleepiness and 68.2% suffered from job problems. Our study shows that evaluation of DQB1*0602 in patients suspected to narcolepsy could be helpful especially in complex cases with atypical cataplexy and indistinguishable multiple sleep latency test MSLT results. Moreover, high rates of car accidents and job problems are found among narcoleptic patients.

DUII control system performance measures for Oregon counties 1991-2001

DOT National Transportation Integrated Search

2002-06-01

Driving Under the Influence of Intoxicants (DUII) is a complex social problem that has origins in both internal and external system factors. Due to its complexity, Oregon communities and involved agencies must concentrate on addressing the negative r...

The Shock and Vibration Digest, Volume 18, Number 3

DTIC Science & Technology

1986-03-01

Linear Distributed Parameter Des., Proc. Intl. Symp., 11th ONR Naval Struc. Systems by Shifted Legendre Polynomial Func- Mech. Symp., Tucson, AZ, pp...University, Atlanta, Georgia nonlinear problems with elementary algebra . It J. Sound Vib., 102 (2), pp 247-257 (Sept 22, uses i = -1, the Pascal’s...eigenvalues specified. The optimal avoid failure due to resonance under the action control problem of a linear distributed parameter 0School of Mechanical

Deterministic methods for multi-control fuel loading optimization

NASA Astrophysics Data System (ADS)

Rahman, Fariz B. Abdul

We have developed a multi-control fuel loading optimization code for pressurized water reactors based on deterministic methods. The objective is to flatten the fuel burnup profile, which maximizes overall energy production. The optimal control problem is formulated using the method of Lagrange multipliers and the direct adjoining approach for treatment of the inequality power peaking constraint. The optimality conditions are derived for a multi-dimensional multi-group optimal control problem via calculus of variations. Due to the Hamiltonian having a linear control, our optimal control problem is solved using the gradient method to minimize the Hamiltonian and a Newton step formulation to obtain the optimal control. We are able to satisfy the power peaking constraint during depletion with the control at beginning of cycle (BOC) by building the proper burnup path forward in time and utilizing the adjoint burnup to propagate the information back to the BOC. Our test results show that we are able to achieve our objective and satisfy the power peaking constraint during depletion using either the fissile enrichment or burnable poison as the control. Our fuel loading designs show an increase of 7.8 equivalent full power days (EFPDs) in cycle length compared with 517.4 EFPDs for the AP600 first cycle.

Reliability of Fault Tolerant Control Systems. Part 2

NASA Technical Reports Server (NTRS)

Wu, N. Eva

2000-01-01

This paper reports Part II of a two part effort that is intended to delineate the relationship between reliability and fault tolerant control in a quantitative manner. Reliability properties peculiar to fault-tolerant control systems are emphasized, such as the presence of analytic redundancy in high proportion, the dependence of failures on control performance, and high risks associated with decisions in redundancy management due to multiple sources of uncertainties and sometimes large processing requirements. As a consequence, coverage of failures through redundancy management can be severely limited. The paper proposes to formulate the fault tolerant control problem as an optimization problem that maximizes coverage of failures through redundancy management. Coverage modeling is attempted in a way that captures its dependence on the control performance and on the diagnostic resolution. Under the proposed redundancy management policy, it is shown that an enhanced overall system reliability can be achieved with a control law of a superior robustness, with an estimator of a higher resolution, and with a control performance requirement of a lesser stringency.

Contrasting Perspectives Of Junior versus Senior NASA ISS Flight Controllers On Leadership And Cultural Issues

NASA Technical Reports Server (NTRS)

Clement, James L.; Boyd, J. E.; Saylor, S.; Kanas, N.

2007-01-01

NASA flight controllers have always worked in a very demanding environment, but the International Space Station (ISS) poses even more challenges than prior missions. A recent NASA/Ames survey by Parke and Orasanu of NASA/Johnson flight controllers uncovered concerns about communications problems between American personnel and their international counterparts. To better understand these problems, we interviewed 14 senior and 12 junior ISS flight controllers at NASA/Johnson about leadership and cultural challenges they face and strategies for addressing these challenges. The qualitative interview data were coded and tabulated. Here we present quantitative analyses testing for differences between junior and senior controllers. Based on nonparametric statistical tests comparing responses across groups, the senior controllers were significantly more aware of the impact of working in dispersed teams, the context of constant change, and the upcoming multilateral challenges, while junior controllers were more aware of language and cultural issues. We consider our findings in light of other studies of controllers and other known differences between senior and junior controllers. For example, the fact that senior controllers had their formative early experience controlling pre-ISS short-duration Shuttle missions seems to have both positive and negative aspects, which are supported by our data. Our findings may also reflect gender differences, but we cannot unconfound this effect in our data because all the senior respondents were males. Many of the junior-senior differences are not only due to elapsed time on the job, but also due to a cohort effect. The findings of this study should be used for training curricula tailored differently for junior and senior controllers.

A dynamic method to forecast the wheel slip for antilock braking system and its experimental evaluation.

PubMed

Oniz, Yesim; Kayacan, Erdal; Kaynak, Okyay

2009-04-01

The control of an antilock braking system (ABS) is a difficult problem due to its strongly nonlinear and uncertain characteristics. To overcome this difficulty, the integration of gray-system theory and sliding-mode control is proposed in this paper. This way, the prediction capabilities of the former and the robustness of the latter are combined to regulate optimal wheel slip depending on the vehicle forward velocity. The design approach described is novel, considering that a point, rather than a line, is used as the sliding control surface. The control algorithm is derived and subsequently tested on a quarter vehicle model. Encouraged by the simulation results indicating the ability to overcome the stated difficulties with fast convergence, experimental results are carried out on a laboratory setup. The results presented indicate the potential of the approach in handling difficult real-time control problems.

The EMIR experience in the use of software control simulators to speed up the time to telescope

NASA Astrophysics Data System (ADS)

Lopez Ramos, Pablo; López-Ruiz, J. C.; Moreno Arce, Heidy; Rosich, Josefina; Perez Menor, José Maria

2012-09-01

One of the main problems facing development teams working on instrument control systems consists on the need to access mechanisms which are not available until well into the integration phase. The need to work with real hardware creates additional problems like, among others: certain faults cannot be tested due to the possibility of hardware damage, taking the system to the limit may shorten its operational lifespan and the full system may not be available during some periods due to maintenance and/or testing of individual components. These problems can be treated with the use of simulators and by applying software/hardware standards. Since information on the construction and performance of electro-mechanical systems is available at relatively early stages of the project, simulators are developed in advance (before the existence of the mechanism) or, if conventions and standards have been correctly followed, a previously developed simulator might be used. This article describes our experience in building software simulators and the main advantages we have identified, which are: the control software can be developed even in the absence of real hardware, critical tests can be prepared using the simulated systems, test system behavior for hardware failure situations that represent a risk of the real system, and the speed up of in house integration of the entire instrument. The use of simulators allows us to reduce development, testing and integration time.

Healthcare-associated infections in intensive care units: epidemiology and infection control in low-to-middle income countries.

PubMed

Alp, Emine; Damani, Nizam

2015-10-29

Healthcare-associated infections (HAIs) are major patient safety problems in hospitals, especially in intensive care units (ICUs). Patients in ICUs are prone to HAIs due to reduced host defense mechanisms, low compliance with infection prevention and control (IPC) measures due to lack of education and training, and heavy workload and low staffing levels, leading to cross-transmission of microorganisms from patient to patient. Patients with HAIs have prolonged hospital stays, and have high morbidity and mortality, thus adding economic burden on the healthcare system. For various reasons, in low-to-middle income countries (LMICs), the scale of the problem is huge; each year, many people die from HAIs. In this review, epidemiology of HAIs and infection prevention and control measures in ICUs is discussed, with especial emphasis on LMICs. High rates of HAIs caused by multidrug-resistant organisms (MDROs) are serious problems in ICUs in LMICs. In view of increasing prevalence of MDROs, LMICs should establish effective IPC infrastructure, appoint IPC teams, and provide adequate training and resources. These resources to establish and appoint IPC teams can be released by avoiding ritualistic, wasteful, and unsafe IPC practices, and by diverting resources to implement basic IPC measures, including early detection of infection, isolation of patients, application of appropriate IPC precautions, adherence to hand hygiene, and implementation of HAIs care bundles and basic evidence-based practices.

Treatment of Posttraumatic Stress Disorder by Trained Lay Counselors in an African Refugee Settlement: A Randomized Controlled Trial

ERIC Educational Resources Information Center

Neuner, Frank; Onyut, Patience Lamaro; Ertl, Verena; Odenwald, Michael; Schauer, Elisabeth; Elbert, Thomas

2008-01-01

Traumatic stress due to conflict and war causes major mental health problems in many resource-poor countries. The objective of this study was to examine whether trained lay counselors can carry out effective treatment of posttraumatic stress disorder (PTSD) in a refugee settlement. In a randomized controlled dissemination trial in Uganda with 277…

Displacement control of an antagonistic-type twisted and coiled polymer actuator

NASA Astrophysics Data System (ADS)

Suzuki, Motoya; Kamamichi, Norihiro

2018-03-01

A novel artificial muscle actuator referred to as a twisted and coiled polymer actuator can be easily fabricated by commercially available nylon fibers. It can be thermally activated and has remarkable properties such as large deformation and flexibility. The actuator uses conductive nylon fibers and can be activated by Joule heating and is easily controlled electrically. However, asymmetric response characteristics due to a speed difference in heating-cooling are a problem. In the case of actuation in air, the cooling speed depends on the external temperature, and is slower than the heating speed. To solve these problems, we apply an antagonistic structure. The validity of the applied method is investigated through numerical simulations and experiments. The response characteristics of the PID feedback control and the 2-DOF control of the displacement are investigated.

Active Control of Generalized Complex Modal Structures in a Stochastic Environment

DTIC Science & Technology

1992-05-15

began with the design of a baseline controller. The system of interest was a MIMO, heavily damped structure with complex modes, and the control objective...feed-through term in our system that was due to the use of accelerometers as sensors. This provided an acceptable baseline solution to our I problem...to which we could compare our ideas for improvement. One area in which the baseline design was deficient was robust stability to unstructured

Applications of Sharp Interface Method for Flow Dynamics, Scattering and Control Problems

DTIC Science & Technology

2012-07-30

Reynolds number, Advances in Applied Mathematics and Mechanics, to appear. 17. K. Ito and K. Kunisch, Optimal Control of Parabolic Variational ...provides more precise and detailed sensitivity of the solution and describes the dynamical change due to the variation in the Reynolds number. The immersed... Inequalities , Journal de Math. Pures et Appl, 93 (2010), no. 4, 329-360. 18. K. Ito and K. Kunisch, Semi-smooth Newton Methods for Time-Optimal Control for a

Localized Tissue Surrogate Deformation due to Controlled Single Bubble Cavitation

DTIC Science & Technology

2014-08-27

calculate liquid jet formation with collapse of an empty spherical bubble due to the high surrounding fluid pressure 18. Experimental evidence of...maximum collapse pressures over a wide range between 8 MPa 13 to 2.5 GPa 11 have also been calculated . 5 A fundamental problem in the study of...and a digital image correlation (DIC) technique was used to calculate strain fields during bubble growth and collapse. The subsequent response of the

Using mobile probes to inform and measure the effectiveness of traffic control strategies on urban networks.

DOT National Transportation Integrated Search

2015-07-01

Urban traffic congestion is a problem that plagues many cities in the United States. Testing strategies to alleviate this : congestion is especially challenging due to the difficulty of modeling complex urban traffic networks. However, recent work ha...

The effect of negative performance stereotypes on learning.

PubMed

Rydell, Robert J; Rydell, Michael T; Boucher, Kathryn L

2010-12-01

Stereotype threat (ST) research has focused exclusively on how negative group stereotypes reduce performance. The present work examines if pejorative stereotypes about women in math inhibit their ability to learn the mathematical rules and operations necessary to solve math problems. In Experiment 1, women experiencing ST had difficulty encoding math-related information into memory and, therefore, learned fewer mathematical rules and showed poorer math performance than did controls. In Experiment 2, women experiencing ST while learning modular arithmetic (MA) performed more poorly than did controls on easy MA problems; this effect was due to reduced learning of the mathematical operations underlying MA. In Experiment 3, ST reduced women's, but not men's, ability to learn abstract mathematical rules and to transfer these rules to a second, isomorphic task. This work provides the first evidence that negative stereotypes about women in math reduce their level of mathematical learning and demonstrates that reduced learning due to stereotype threat can lead to poorer performance in negatively stereotyped domains. PsycINFO Database Record (c) 2010 APA, all rights reserved.

Active Control of Panel Vibrations Induced by a Boundary Layer Flow

NASA Technical Reports Server (NTRS)

Chow, Pao-Liu

1998-01-01

In recent years, active and passive control of sound and vibration in aeroelastic structures have received a great deal of attention due to many potential applications to aerospace and other industries. There exists a great deal of research work done in this area. Recent advances in the control of sound and vibration can be found in the several conference proceedings. In this report we will summarize our research findings supported by the NASA grant NAG-1-1175. The problems of active and passive control of sound and vibration has been investigated by many researchers for a number of years. However, few of the articles are concerned with the sound and vibration with flow-structure interaction. Experimental and numerical studies on the coupling between panel vibration and acoustic radiation due to flow excitation have been done by Maestrello and his associates at NASA/Langley Research Center. Since the coupled system of nonlinear partial differential equations is formidable, an analytical solution to the full problem seems impossible. For this reason, we have to simplify the problem to that of the nonlinear panel vibration induced by a uniform flow or a boundary-layer flow with a given wall pressure distribution. Based on this simplified model, we have been able to study the control and stabilization of the nonlinear panel vibration, which have not been treated satisfactorily by other authors. The vibration suppression will clearly reduce the sound radiation power from the panel. The major research findings will be presented in the next three sections. In Section II we shall describe our results on the boundary control of nonlinear panel vibration, with or without flow excitation. Section III is concerned with active control of the vibration and sound radiation from a nonlinear elastic panel. A detailed description of our work on the parametric vibrational control of nonlinear elastic panel will be presented in Section IV. This paper will be submitted to the Journal of Acoustic Society of America for publication.

Automatic Quality Inspection of Percussion Cap Mass Production by Means of 3D Machine Vision and Machine Learning Techniques

NASA Astrophysics Data System (ADS)

Tellaeche, A.; Arana, R.; Ibarguren, A.; Martínez-Otzeta, J. M.

The exhaustive quality control is becoming very important in the world's globalized market. One of these examples where quality control becomes critical is the percussion cap mass production. These elements must achieve a minimum tolerance deviation in their fabrication. This paper outlines a machine vision development using a 3D camera for the inspection of the whole production of percussion caps. This system presents multiple problems, such as metallic reflections in the percussion caps, high speed movement of the system and mechanical errors and irregularities in percussion cap placement. Due to these problems, it is impossible to solve the problem by traditional image processing methods, and hence, machine learning algorithms have been tested to provide a feasible classification of the possible errors present in the percussion caps.

A review of supersonic cruise flight path control experience with the YF-12 aircraft

NASA Technical Reports Server (NTRS)

Berry, D. T.; Gilyard, G. B.

1976-01-01

Flight research with the YF-12 aircraft indicates that solutions to many handling qualities problems of supersonic cruise are at hand. Airframe/propulsion system interactions in the Dutch roll mode can be alleviated by the use of passive filters or additional feedback loops in the propulsion and flight control systems. Mach and altitude excursions due to atmospheric temperature fluctuations can be minimized by the use of a cruise autothrottle. Autopilot instabilities in the altitude hold mode have been traced to angle of attack-sensitive static ports on the compensated nose boom. For the YF-12, the feedback of high-passed pitch rate to the autopilot resolves this problem. Manual flight path control is significantly improved by the use of an inertial rate of climb display in the cockpit.

Multirate control with incomplete information over Profibus-DP network

NASA Astrophysics Data System (ADS)

Salt, J.; Casanova, V.; Cuenca, A.; Pizá, R.

2014-07-01

When a process field bus-decentralized peripherals (Profibus-DP) network is used in an industrial environment, a deterministic behaviour is usually claimed. However, due to some concerns such as bandwidth limitations, lack of synchronisation among different clocks and existence of time-varying delays, a more complex problem must be faced. This problem implies the transmission of irregular and, even, random sequences of incomplete information. The main consequence of this issue is the appearance of different sampling periods at different network devices. In this paper, this aspect is checked by means of a detailed Profibus-DP timescale study. In addition, in order to deal with the different periods, a delay-dependent dual-rate proportional-integral-derivative control is introduced. Stability for the proposed control system is analysed in terms of linear matrix inequalities.

A Control Allocation System for Automatic Detection and Compensation of Phase Shift Due to Actuator Rate Limiting

NASA Technical Reports Server (NTRS)

Yildiz, Yidiray; Kolmanovsky, Ilya V.; Acosta, Diana

2011-01-01

This paper proposes a control allocation system that can detect and compensate the phase shift between the desired and the actual total control effort due to rate limiting of the actuators. Phase shifting is an important problem in control system applications since it effectively introduces a time delay which may destabilize the closed loop dynamics. A relevant example comes from flight control where aggressive pilot commands, high gain of the flight control system or some anomaly in the system may cause actuator rate limiting and effective time delay introduction. This time delay can instigate Pilot Induced Oscillations (PIO), which is an abnormal coupling between the pilot and the aircraft resulting in unintentional and undesired oscillations. The proposed control allocation system reduces the effective time delay by first detecting the phase shift and then minimizing it using constrained optimization techniques. Flight control simulation results for an unstable aircraft with inertial cross coupling are reported, which demonstrate phase shift minimization and recovery from a PIO event.

Coordinated control of active and reactive power of distribution network with distributed PV cluster via model predictive control

NASA Astrophysics Data System (ADS)

Ji, Yu; Sheng, Wanxing; Jin, Wei; Wu, Ming; Liu, Haitao; Chen, Feng

2018-02-01

A coordinated optimal control method of active and reactive power of distribution network with distributed PV cluster based on model predictive control is proposed in this paper. The method divides the control process into long-time scale optimal control and short-time scale optimal control with multi-step optimization. The models are transformed into a second-order cone programming problem due to the non-convex and nonlinear of the optimal models which are hard to be solved. An improved IEEE 33-bus distribution network system is used to analyse the feasibility and the effectiveness of the proposed control method

A wavefront compensation approach to segmented mirror figure control

NASA Technical Reports Server (NTRS)

Redding, David; Breckenridge, Bill; Sevaston, George; Lau, Ken

1991-01-01

We consider the 'figure-control' problem for a spaceborn sub-millimeter wave telescope, the Precision Segmented Reflector Project Focus Mission Telescope. We show that performance of any figure control system is subject to limits on the controllability and observability of the quality of the wavefront. We present a wavefront-compensation method for the Focus Mission Telescope which uses mirror-figure sensors and three-axis segment actuator to directly minimize wavefront errors due to segment position errors. This approach shows significantly better performance when compared with a panel-state-compensation approach.

E-16211

NASA Image and Video Library

1966-12-22

The HL-10 Lifting Body completes its first research flight with a landing on Rogers Dry Lake. Due to control problems, pilot Bruce Peterson had to land at a higher speed than originally planned in order to keep the vehicle under control. The actual touchdown speed was about 280 knots. This was 30 knots above the speed called for in the flight plan. The HL-10's first flight had lasted 3 minutes and 9 seconds.

Challenges in Addressing Variability Of Lead in Domestic Plumbing

EPA Science Inventory

Current data indicate that lead exposure is of concern even at low concentrations. Corrosion is an important problem in drinking water because it can affect public health due to leaching of lead or other metals into the drinking water. For this reason, a corrosion control program...

Using mobile probes to inform and measure the effectiveness of macroscopic traffic control strategies on urban networks.

DOT National Transportation Integrated Search

2015-06-01

Urban traffic congestion is a problem that plagues many cities in the United States. Testing strategies to alleviate this : congestion is especially challenging due to the difficulty of modeling complex urban traffic networks. However, recent work ha...

Concerns about losing control when breaking bad news to terminally ill patients with cancer: physicians' perspective.

PubMed

Friedrichsen, Maria; Milberg, Anna

2006-06-01

To study and explore problems perceived by physicians when breaking bad news to advanced cancer patients about discontinuing or not offering tumor-specific treatment due to incurable cancer. A qualitative phenomenographic interview study. The county of Ostergötland in Sweden. Thirty physicians with different demographic characteristics. According to the physicians' answers breaking bad news was perceived as involving a risk of losing control in different ways, regarding emotions, oneself, confidence, professionalism and patient trust. Four different main categories described as problems were identified; perceptions focusing on existential thoughts, relationships, knowledge, and perceptions related to time and environmental disturbances. Physicians perceived that breaking bad news to dying patients with cancer involved a risk of losing control. Existential thoughts and a lack of knowledge contribute to this risk. Theoretical education in existentiality/spirituality and clinical practice in a palliative context may help maintaining control.

Caregiving-Related Sleep Problems and Their Relationship to Mental Health and Daytime Function in Female Veterans.

PubMed

Song, Yeonsu; Washington, Donna L; Yano, Elizabeth M; McCurry, Susan M; Fung, Constance H; Dzierzewski, Joseph M; Rodriguez, Juan Carlos; Jouldjian, Stella; Mitchell, Michael N; Alessi, Cathy A; Martin, Jennifer L

2018-01-01

To identify caregiving-related sleep problems and their relationship to mental health and daytime function in female Veterans. Female Veterans (N = 1,477) from cross-sectional, nationwide, postal survey data. The survey respondent characteristics included demographics, comorbidity, physical activity, health, use of sleep medications, and history of sleep apnea. They self-identified caregiving- related sleep problems (i.e., those who had trouble sleeping because of caring for a sick adult, an infant/child, or other respondents). Patient Health Questionnaire (PHQ-4) was used to assess mental health, and daytime function was measured using 11 items of International Classification of Sleep Disorders-2 (ICSD-2). Female Veterans with self-identified sleep problems due to caring for a sick adult (n = 59) experienced significantly more symptoms of depression and anxiety (p < 0.001) and impairment in daytime function (e.g., fatigue, daytime sleepiness, loss of concentration, p < 0.001) than those with self-identified sleep problems due to caring for an infant or child (n = 95) or all other respondents (n = 1,323) after controlling for the respondent characteristics. Healthcare providers should pay attention to assessing sleep characteristics of female Veterans with caregiving responsibilities, particularly those caregiving for a sick adult.

System analysis of vehicle active safety problem

NASA Astrophysics Data System (ADS)

Buznikov, S. E.

2018-02-01

The problem of the road transport safety affects the vital interests of the most of the population and is characterized by a global level of significance. The system analysis of problem of creation of competitive active vehicle safety systems is presented as an interrelated complex of tasks of multi-criterion optimization and dynamic stabilization of the state variables of a controlled object. Solving them requires generation of all possible variants of technical solutions within the software and hardware domains and synthesis of the control, which is close to optimum. For implementing the task of the system analysis the Zwicky “morphological box” method is used. Creation of comprehensive active safety systems involves solution of the problem of preventing typical collisions. For solving it, a structured set of collisions is introduced with its elements being generated also using the Zwicky “morphological box” method. The obstacle speed, the longitudinal acceleration of the controlled object and the unpredictable changes in its movement direction due to certain faults, the road surface condition and the control errors are taken as structure variables that characterize the conditions of collisions. The conditions for preventing typical collisions are presented as inequalities for physical variables that define the state vector of the object and its dynamic limits.

Hypersensitivity to reward in problem gamblers.

PubMed

Hewig, Johannes; Kretschmer, Nora; Trippe, Ralf H; Hecht, Holger; Coles, Michael G H; Holroyd, Clay B; Miltner, Wolfgang H R

2010-04-15

Recent research has begun to examine the neurophysiologic basis of pathological gambling. However, direct evidence of a behavioral deficit and an accompanying neurofunctional deviation in a realistic gambling context such as Black Jack has not yet been reported. Electroencephalogram was recorded while 20 problem gamblers and 21 control participants played a computerized version of Black Jack. Participants were asked to decide at point scores between 11 and 21 whether they wanted to take another card ("hit") to arrive closer to 21 than the opponent (simulated by computer) or not to take another card ("sit") to avoid going over 21 ("bust"). At a critical point score of 16, problem gamblers decided more often to hit despite losses due to a bust on the preceding trial, whereas control participants decided more often to sit under these conditions. Furthermore, problem gamblers showed more reward-related positive amplitudes in the event-related brain potential than control participants after successful hit decisions at 16. Here we provide experimental evidence for high-risk taking behavior in gamblers and its correlate in event-related brain potentials. Our results suggest that high-risk-taking behavior in problem gamblers is associated with an increased reward-related neural response to infrequent successes of this behavior. Copyright 2010 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

The effect of problem solving and decision making skills on tendency to depression and anxiety in patients with type 2 diabetes.

PubMed

Abazarian, Elaheh; Baboli, M Teimourzadeh; Abazarian, Elham; Ghashghaei, F Esteki

2015-01-01

Diabetes is the most prevalent disease that has involved 177 million people all over the world and, due to this, these patients suffer from depression and anxiety and they should use special methods for controlling the same. The aim of this research is the study of the effect of problem solving and decision making skill on the rate of the tendency to depression and anxiety. This research is a quasi-experimental (case-control) study. Statistically, the population of the present study was all diabetic patients of Qaemshahr who were controlled by physicians in 2011-2012. Thirty files were selected randomly from them and divided into two 15 patients' groups (control and subject group) randomly. The measurement tools were Back depression inventory (21 items) and Zank anxiety questionnaire that were distributed among two groups. Then, the subject group participated in eight sessions of teaching problem solving and decision making courses separately, and the second group (control group) did not receive any instruction. Finally, both groups had passed post-test and the data obtained from the questionnaires were studied by variance analysis statistical methods. The results showed that teaching problem solving and decision making skills was very effective in reducing diabetic patients' depression and anxiety and resulted in reducing their depression and anxiety.

The effect of problem solving and decision making skills on tendency to depression and anxiety in patients with type 2 diabetes

PubMed Central

Abazarian, Elaheh; Baboli, M Teimourzadeh; Abazarian, Elham; Ghashghaei, F Esteki

2015-01-01

Background: Diabetes is the most prevalent disease that has involved 177 million people all over the world and, due to this, these patients suffer from depression and anxiety and they should use special methods for controlling the same. The aim of this research is the study of the effect of problem solving and decision making skill on the rate of the tendency to depression and anxiety. Materials and Methods: This research is a quasi-experimental (case-control) study. Statistically, the population of the present study was all diabetic patients of Qaemshahr who were controlled by physicians in 2011-2012. Thirty files were selected randomly from them and divided into two 15 patients’ groups (control and subject group) randomly. The measurement tools were Back depression inventory (21 items) and Zank anxiety questionnaire that were distributed among two groups. Then, the subject group participated in eight sessions of teaching problem solving and decision making courses separately, and the second group (control group) did not receive any instruction. Results: Finally, both groups had passed post-test and the data obtained from the questionnaires were studied by variance analysis statistical methods. Conclusion: The results showed that teaching problem solving and decision making skills was very effective in reducing diabetic patients’ depression and anxiety and resulted in reducing their depression and anxiety. PMID:26261814

Early Workplace Communication and Problem Solving to Prevent Back Disability: Results of a Randomized Controlled Trial Among High-Risk Workers and Their Supervisors.

PubMed

Linton, Steven J; Boersma, Katja; Traczyk, Michal; Shaw, William; Nicholas, Michael

2016-06-01

Purpose There is a clear need for interventions that successfully prevent the development of disability due to back pain. We hypothesized that an intervention aimed at both the worker and the workplace could be effective. Hence, we tested the effects of a new early intervention, based on the misdirected problem solving model, aimed at both workers at risk of long-term impairments and their workplace. Methods Supervisors of volunteers with back pain, no red flags, and a high score on a screen (Örebro Musculoskeletal Screening Questionnaire) were randomized to either an evidence based treatment as usual (TAU) or to a worker and workplace package (WWP). The WWP intervention included communication and problem solving skills for the patient and their immediate supervisor. The key outcome variables of work absence due to pain, health-care utilization, perceived health, and pain intensity were collected before, after and at a 6 month follow up. Results The WWP showed significantly larger improvements relative to the TAU for work absence due to pain, perceived health, and health-care utilization. Both groups improved on pain ratings but there was no significant difference between the groups. The WWP not only had significantly fewer participants utilizing health care and work absence due to pain, but the number of health care visits and days absent were also significantly lower than the TAU. Conclusions The WWP with problem solving and communication skills resulted in fewer days off work, fewer health care visits and better perceived health. This supports the misdirected problem solving model and indicates that screening combined with an active intervention to enhance skills is quite successful and likely cost-effective. Future research should replicate and extend these findings with health-economic analyses.

Odor and odorous chemical emissions from animal buildings: part 1 - project overview, collection methods, and quality control

USDA-ARS?s Scientific Manuscript database

Livestock facilities have historically generated public concerns due to their emissions of odorous air and various chemical pollutants. Odor emission factors and identification of principal odorous chemicals are needed to better understand the problem. Applications of odor emission factors include i...

Watershed Restoration in the Northern Sierra Nevada: A Biotechnical Approach

Treesearch

Donna S. Lindquist; Linton Y. Bowie

1989-01-01

A cooperative erosion control project was initiated in 1985 for the North Fork Feather River watershed in California's northern Sierra Nevada due to widespread accelerated erosion. Resulting sedimentation problems have impacted fish, wildlife and livestock resources, and have created operational concerns for hydroelectric facilities located downstream. In response...

Impact of lightning strikes on hospital functions.

PubMed

Mortelmans, Luc J M; Van Springel, Gert L J; Van Boxstael, Sam; Herrijgers, Jan; Hoflacks, Stefaan

2009-01-01

Two regional hospitals were struck by lightning during a one-month period. The first hospital, which had 236 beds, suffered a direct strike to the building. This resulted in a direct spread of the power peak and temporary failure of the standard power supply. The principle problems, after restoring standard power supply, were with the fire alarm system and peripheral network connections in the digital radiology systems. No direct impact on the hardware could be found. Restarting the servers resolved all problems. The second hospital, which had 436 beds, had a lightning strike on the premises and mainly experienced problems due to induction. All affected installations had a cable connection from outside in one way or another. The power supplies never were endangered. The main problem was the failure of different communication systems (telephone, radio, intercom, fire alarm system). Also, the electronic entrance control went out. During the days after the lightening strike, multiple software problems became apparent, as well as failures of the network connections controlling the technical support systems. There are very few ways to prepare for induction problems. The use of fiber-optic networks can limit damage. To the knowledge of the authors, these are the first cases of lightning striking hospitals in medical literature.

Digitalizing historical high resolution water level data: Challenges and opportunities

NASA Astrophysics Data System (ADS)

Holinde, Lars; Hein, Hartmut; Barjenbruch, Ulrich

2017-04-01

Historical tide-gauge data offer the opportunities for determining variations in key characteristics for water level data and the analyses of past extreme events (storm surges). These information are important for calculating future trends and scenarios. But there are challenges involved due to the extensive effort needed to digitalize gauge sheets and quality control the resulting historical data. Based on these conditions, two main sources for inaccuracies in historical time series can be identified. First are several challenges due to the digitalization of the historical data, e.g. general quality of the sheets, multiple crossing lines of the observed water levels and additional comments on the sheet describing problems or additional information during the measurements. Second are problems during the measurements themselves. These can include the incorrect positioning of the sheets, trouble with the tide-gauge and maintenance. Errors resulting from these problems can be e.g. flat lines, discontinuities and outlier. Especially, the characterization of outliers has to be conducted carefully, to distinguish between real outliers and the appearance of extreme events. Methods for the quality control process involve the use of statistics, machine learning and neural networks. These will be described and applied to three different time series from tide gauge stations at the cost of Lower Saxony, Germany. Resulting difficulties and outcomes of the quality control process will be presented and explained. Furthermore, we will present a first glance at analyses for these time series.

Distributed Optimization of Multi-Agent Systems: Framework, Local Optimizer, and Applications

NASA Astrophysics Data System (ADS)

Zu, Yue

Convex optimization problem can be solved in a centralized or distributed manner. Compared with centralized methods based on single-agent system, distributed algorithms rely on multi-agent systems with information exchanging among connected neighbors, which leads to great improvement on the system fault tolerance. Thus, a task within multi-agent system can be completed with presence of partial agent failures. By problem decomposition, a large-scale problem can be divided into a set of small-scale sub-problems that can be solved in sequence/parallel. Hence, the computational complexity is greatly reduced by distributed algorithm in multi-agent system. Moreover, distributed algorithm allows data collected and stored in a distributed fashion, which successfully overcomes the drawbacks of using multicast due to the bandwidth limitation. Distributed algorithm has been applied in solving a variety of real-world problems. Our research focuses on the framework and local optimizer design in practical engineering applications. In the first one, we propose a multi-sensor and multi-agent scheme for spatial motion estimation of a rigid body. Estimation performance is improved in terms of accuracy and convergence speed. Second, we develop a cyber-physical system and implement distributed computation devices to optimize the in-building evacuation path when hazard occurs. The proposed Bellman-Ford Dual-Subgradient path planning method relieves the congestion in corridor and the exit areas. At last, highway traffic flow is managed by adjusting speed limits to minimize the fuel consumption and travel time in the third project. Optimal control strategy is designed through both centralized and distributed algorithm based on convex problem formulation. Moreover, a hybrid control scheme is presented for highway network travel time minimization. Compared with no controlled case or conventional highway traffic control strategy, the proposed hybrid control strategy greatly reduces total travel time on test highway network.

Dynamic optimization case studies in DYNOPT tool

NASA Astrophysics Data System (ADS)

Ozana, Stepan; Pies, Martin; Docekal, Tomas

2016-06-01

Dynamic programming is typically applied to optimization problems. As the analytical solutions are generally very difficult, chosen software tools are used widely. These software packages are often third-party products bound for standard simulation software tools on the market. As typical examples of such tools, TOMLAB and DYNOPT could be effectively applied for solution of problems of dynamic programming. DYNOPT will be presented in this paper due to its licensing policy (free product under GPL) and simplicity of use. DYNOPT is a set of MATLAB functions for determination of optimal control trajectory by given description of the process, the cost to be minimized, subject to equality and inequality constraints, using orthogonal collocation on finite elements method. The actual optimal control problem is solved by complete parameterization both the control and the state profile vector. It is assumed, that the optimized dynamic model may be described by a set of ordinary differential equations (ODEs) or differential-algebraic equations (DAEs). This collection of functions extends the capability of the MATLAB Optimization Tool-box. The paper will introduce use of DYNOPT in the field of dynamic optimization problems by means of case studies regarding chosen laboratory physical educational models.

Results of an integrated structure/control law design sensitivity analysis

NASA Technical Reports Server (NTRS)

Gilbert, Michael G.

1989-01-01

A design sensitivity analysis method for Linear Quadratic Cost, Gaussian (LQG) optimal control laws, which predicts change in the optimal control law due to changes in fixed problem parameters using analytical sensitivity equations is discussed. Numerical results of a design sensitivity analysis for a realistic aeroservoelastic aircraft example are presented. In this example, the sensitivity of the optimally controlled aircraft's response to various problem formulation and physical aircraft parameters is determined. These results are used to predict the aircraft's new optimally controlled response if the parameter was to have some other nominal value during the control law design process. The sensitivity results are validated by recomputing the optimal control law for discrete variations in parameters, computing the new actual aircraft response, and comparing with the predicted response. These results show an improvement in sensitivity accuracy for integrated design purposes over methods which do not include changes in the optimal control law. Use of the analytical LQG sensitivity expressions is also shown to be more efficient than finite difference methods for the computation of the equivalent sensitivity information.

Vibration attenuation of the NASA Langley evolutionary structure experiment using H(sub infinity) and structured singular value (micron) robust multivariable control techniques

NASA Technical Reports Server (NTRS)

Balas, Gary J.

1992-01-01

The use is studied of active control to attenuate structural vibrations of the NASA Langley Phase Zero Evolutionary Structure due to external disturbance excitations. H sub infinity and structured singular value (mu) based control techniques are used to analyze and synthesize control laws for the NASA Langley Controls Structures Interaction (CSI) Evolutionary Model (CEM). The CEM structure experiment provides an excellent test bed to address control design issues for large space structures. Specifically, control design for structures with numerous lightly damped, coupled flexible modes, collocated and noncollocated sensors and actuators and stringent performance specifications. The performance objectives are to attenuate the vibration of the structure due to external disturbances, and minimize the actuator control force. The control design problem formulation for the CEM Structure uses a mathematical model developed with finite element techniques. A reduced order state space model for the control design is formulated from the finite element model. It is noted that there are significant variations between the design model and the experimentally derived transfer function data.

Gyrodampers for large space structures

NASA Technical Reports Server (NTRS)

Aubrun, J. N.; Margulies, G.

1979-01-01

The problem of controlling the vibrations of a large space structures by the use of actively augmented damping devices distributed throughout the structure is addressed. The gyrodamper which consists of a set of single gimbal control moment gyros which are actively controlled to extract the structural vibratory energy through the local rotational deformations of the structure, is described and analyzed. Various linear and nonlinear dynamic simulations of gyrodamped beams are shown, including results on self-induced vibrations due to sensor noise and rotor imbalance. The complete nonlinear dynamic equations are included. The problem of designing and sizing a system of gyrodampers for a given structure, or extrapolating results for one gyrodamped structure to another is solved in terms of scaling laws. Novel scaling laws for gyro systems are derived, based upon fundamental physical principles, and various examples are given.

Automatic Generation Control Study in Two Area Reheat Thermal Power System

NASA Astrophysics Data System (ADS)

Pritam, Anita; Sahu, Sibakanta; Rout, Sushil Dev; Ganthia, Sibani; Prasad Ganthia, Bibhu

2017-08-01

Due to industrial pollution our living environment destroyed. An electric grid system has may vital equipment like generator, motor, transformers and loads. There is always be an imbalance between sending end and receiving end system which cause system unstable. So this error and fault causing problem should be solved and corrected as soon as possible else it creates faults and system error and fall of efficiency of the whole power system. The main problem developed from this fault is deviation of frequency cause instability to the power system and may cause permanent damage to the system. Therefore this mechanism studied in this paper make the system stable and balance by regulating frequency at both sending and receiving end power system using automatic generation control using various controllers taking a two area reheat thermal power system into account.

A Combined Adaptive Neural Network and Nonlinear Model Predictive Control for Multirate Networked Industrial Process Control.

PubMed

Wang, Tong; Gao, Huijun; Qiu, Jianbin

2016-02-01

This paper investigates the multirate networked industrial process control problem in double-layer architecture. First, the output tracking problem for sampled-data nonlinear plant at device layer with sampling period T(d) is investigated using adaptive neural network (NN) control, and it is shown that the outputs of subsystems at device layer can track the decomposed setpoints. Then, the outputs and inputs of the device layer subsystems are sampled with sampling period T(u) at operation layer to form the index prediction, which is used to predict the overall performance index at lower frequency. Radial basis function NN is utilized as the prediction function due to its approximation ability. Then, considering the dynamics of the overall closed-loop system, nonlinear model predictive control method is proposed to guarantee the system stability and compensate the network-induced delays and packet dropouts. Finally, a continuous stirred tank reactor system is given in the simulation part to demonstrate the effectiveness of the proposed method.

Practical solution for control of the pre-analytical phase in decentralized clinical laboratories for meeting the requirements of the medical laboratory accreditation standard DIN EN ISO 15189.

PubMed

Vacata, Vladimir; Jahns-Streubel, Gerlinde; Baldus, Mirjana; Wood, William Graham

2007-01-01

This report was written in response to the article by Wood published recently in this journal. It describes a practical solution to the problems of controlling the pre-analytical phase in the clinical diagnostic laboratory. As an indicator of quality in the pre-analytical phase of sample processing, a target analyte was chosen which is sensitive to delay in centrifugation and/or analysis. The results of analyses of the samples sent by satellite medical practitioners were compared with those from an on-site hospital laboratory with a controllable optimized pre-analytical phase. The aim of the comparison was: (a) to identify those medical practices whose mean/median sample values significantly deviate from those of the control situation in the hospital laboratory due to the possible problems in the pre-analytical phase; (b) to aid these laboratories in the process of rectifying these problems. A Microsoft Excel-based Pre-Analytical Survey tool (PAS tool) has been developed which addresses the above mentioned problems. It has been tested on serum potassium which is known to be sensitive to delay and/or irregularities in sample treatment. The PAS tool has been shown to be one possibility for improving the quality of the analyses by identifying the sources of problems within the pre-analytical phase, thus allowing them to be rectified. Additionally, the PAS tool has an educational value and can also be adopted for use in other decentralized laboratories.

Automatic control of NASA Langley's 0.3-meter cryogenic test facility

NASA Technical Reports Server (NTRS)

Thibodeaux, J. J.; Balakrishna, S.

1980-01-01

Experience during the past 6 years of operation of the 0.3-meter transonic cryogenic tunnel at the NASA Langley Research Center has shown that there are problems associated with efficient operation and control of cryogenic tunnels using manual control schemes. This is due to the high degree of process crosscoupling between the independent control variables (temperature, pressure, and fan drive speed) and the desired test condition (Mach number and Reynolds number). One problem has been the inability to maintain long-term accurate control of the test parameters. Additionally, the time required to change from one test condition to another has proven to be excessively long and much less efficient than desirable in terms of liquid nitrogen and electrical power usage. For these reasons, studies have been undertaken to: (1) develop and validate a mathematical model of the 0.3-meter cryogenic tunnel process, (2) utilize this model in a hybrid computer simulation to design temperature and pressure feedback control laws, and (3) evaluate the adequacy of these control schemes by analysis of closed-loop experimental data. This paper will present the results of these studies.

A new type of magnetic gimballed momentum wheel and its application to attitude control in space

NASA Astrophysics Data System (ADS)

Murakami, C.; Ohkami, Y.; Okamoto, O.; Nakajima, A.; Inoue, M.; Tsuchiya, J.; Yabu-uchi, K.; Akishita, S.; Kida, T.

A new type of magnetically suspended gimbal momentum wheel utilizing permanent magnets is described. The bearing was composed of four independent thrust actuators which control the rotor thrust position and gimbal angles cooperatively, so that the bearing comes to have a simple mechanism with high reliability and light weight. The high speed instability problem due to the internal damping was easily overcome by introducing anisotropic radial stiffness. A momentum flywheel with the 3-axis controlled magnetic bearing displays good performance for attitude control of satellite with biased momentum.

Sleeping with technology: cognitive, affective, and technology usage predictors of sleep problems among college students.

PubMed

Rosen, Larry; Carrier, Louis M; Miller, Aimee; Rokkum, Jeffrey; Ruiz, Abraham

2016-03-01

Sleep problems related to technology affect college students through several potential mechanisms including displacement of sleep due to technology use, executive functioning abilities, and the impact of emotional states related to stress and anxiety about technology availability. In the present study, cognitive and affective factors that influence technology usage were examined for their impact upon sleep problems. More than 700 US college students completed an online questionnaire addressing technology usage, anxiety/dependence, executive functioning, nighttime phone usage, bedtime phone location, and sleep problems. A path model controlling for background variables was tested using the data. The results showed that executive dysfunction directly predicted sleep problems as well as affected sleep problems through nighttime awakenings. In addition, anxiety/dependence increased daily smartphone usage and also increased nighttime awakenings, which, in turn, affected sleep problems. Thus, both the affective and cognitive factors that influence technology usage affected sleep problems. Copyright © 2016 National Sleep Foundation. Published by Elsevier Inc. All rights reserved.

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

Pin, F.G.; Bender, S.R.

Most fuzzy logic-based reasoning schemes developed for robot control are fully reactive, i.e., the reasoning modules consist of fuzzy rule bases that represent direct mappings from the stimuli provided by the perception systems to the responses implemented by the motion controllers. Due to their totally reactive nature, such reasoning systems can encounter problems such as infinite loops and limit cycles. In this paper, we proposed an approach to remedy these problems by adding a memory and memory-related behaviors to basic reactive systems. Three major types of memory behaviors are addressed: memory creation, memory management, and memory utilization. These are firstmore » presented, and examples of their implementation for the recognition of limit cycles during the navigation of an autonomous robot in a priori unknown environments are then discussed.« less

Artificial Epigenetic Networks: Automatic Decomposition of Dynamical Control Tasks Using Topological Self-Modification.

PubMed

Turner, Alexander P; Caves, Leo S D; Stepney, Susan; Tyrrell, Andy M; Lones, Michael A

2017-01-01

This paper describes the artificial epigenetic network, a recurrent connectionist architecture that is able to dynamically modify its topology in order to automatically decompose and solve dynamical problems. The approach is motivated by the behavior of gene regulatory networks, particularly the epigenetic process of chromatin remodeling that leads to topological change and which underlies the differentiation of cells within complex biological organisms. We expected this approach to be useful in situations where there is a need to switch between different dynamical behaviors, and do so in a sensitive and robust manner in the absence of a priori information about problem structure. This hypothesis was tested using a series of dynamical control tasks, each requiring solutions that could express different dynamical behaviors at different stages within the task. In each case, the addition of topological self-modification was shown to improve the performance and robustness of controllers. We believe this is due to the ability of topological changes to stabilize attractors, promoting stability within a dynamical regime while allowing rapid switching between different regimes. Post hoc analysis of the controllers also demonstrated how the partitioning of the networks could provide new insights into problem structure.

Grain dormancy and light quality effects on germination in the model grass Brachypodium distachyon

USDA-ARS?s Scientific Manuscript database

Lack of seed dormancy in cereal crops such as barley and wheat is a common problem affecting farming areas around the world, causing losses in yield and quality due to pre-harvest sprouting. Control of seed dormancy has been investigated extensively using various approaches in different species incl...

Gait Trainer for Children with Spastic Cerebral Palsy

DTIC Science & Technology

2001-10-25

same person. Spastic CP is the most common type of Cerebral Palsy. It can be subdivided into 5 types : Quadriplegia : A type of CP when occurs in...all four of their limbs-both arms and both legs it is called quadriplegia . Due to the problems of controlling the muscles in their face and upper

Protective effects of Aloe vera-based diets in Eimeria maxima-infected broiler chickens

USDA-ARS?s Scientific Manuscript database

Aloes have been widely used for a broad range of pharmacological activities, including parasitic problems. Avian coccidiosis is the most costly and wide-spread parasitic disease in the poultry industry, and has been mainly controlled by the use of chemotherapeutic agents. Due to the emergence of dru...

Culture, Identity, and Structure in Social Exchange: A Web-Based Trust Experiment in the United States and Japan

ERIC Educational Resources Information Center

Kuwabara, Ko; Willer, Robb; Macy, Michael W.; Mashima, Rie; Terai, Shigeru; Yamagishi, Toshio

2007-01-01

Cross-cultural trust and cooperation are important concerns for international markets, political cooperation, and cultural exchange. Until recently, this problem was difficult to study under controlled conditions due to the inability to conduct experiments involving interaction between participants located in physically distant locations. We…

Modern European monographs for quality control of Chinese herbs.

PubMed

Bauer, Rudolf; Franz, Gerhard

2010-12-01

The actual concern about the safety and efficacy of herbal drugs originating from traditional Chinese medicine (TCM) is based on observations that these medicinal plants may have a high risk potential due to insufficient definitions, problems with identity, purity and falsifications. No uniform legal status for these groups of herbal drugs currently exists in the European Union. For quality control, monographs for TCM herbs can mainly be found in the Pharmacopoeia of the Peoples Republic of China. Based on these facts the Commission of the European Pharmacopoeia decided in 2005 to establish TCM-herbal drug monographs for the most important medicinal plants imported from Far East. These new monographs had to be established and evaluated on the basis of existing monographs in the Chinese Pharmacopoeia (ChP), English edition 2005. Due to important differences in the overall features of EP and ChP, a simple adapt/adopt procedure was not feasible. Therefore, specialist groups were mandated with a corresponding working programme. Some results and actual problems related to this working programme will be presented and discussed. © Georg Thieme Verlag KG Stuttgart · New York.

Nitrogen conservation and acidity control during food wastes composting through struvite formation.

PubMed

Wang, Xuan; Selvam, Ammaiyappan; Chan, Manting; Wong, Jonathan W C

2013-11-01

One of the main problems of food waste composting is the intensive acidification due to initial rapid fermentation that retards decomposition efficiency. Lime addition overcame this problem, but resulted in significant loss of nitrogen as ammonia that reduces the nutrient contents of composts. Therefore, this study investigated the feasibility of struvite formation as a strategy to control pH and reduce nitrogen loss during food waste composting. MgO and K2HPO4 were added to food waste in different molar ratios (P1, 1:1; P2, 1:2), and composted in 20-L composters. Results indicate that K2HPO4 buffered the pH in treatment P2 besides supplementing phosphate into the compost. In P2, organic decomposition reached 64% while the formation of struvite effectively reduced the nitrogen loss from 40.8% to 23.3% during composting. However, electrical conductivity of the compost increased due to the addition of Mg and P salts that requires further investigation to improve this technology. Copyright © 2013 Elsevier Ltd. All rights reserved.

Automatic weight determination in nonlinear model predictive control of wind turbines using swarm optimization technique

NASA Astrophysics Data System (ADS)

Tofighi, Elham; Mahdizadeh, Amin

2016-09-01

This paper addresses the problem of automatic tuning of weighting coefficients for the nonlinear model predictive control (NMPC) of wind turbines. The choice of weighting coefficients in NMPC is critical due to their explicit impact on efficiency of the wind turbine control. Classically, these weights are selected based on intuitive understanding of the system dynamics and control objectives. The empirical methods, however, may not yield optimal solutions especially when the number of parameters to be tuned and the nonlinearity of the system increase. In this paper, the problem of determining weighting coefficients for the cost function of the NMPC controller is formulated as a two-level optimization process in which the upper- level PSO-based optimization computes the weighting coefficients for the lower-level NMPC controller which generates control signals for the wind turbine. The proposed method is implemented to tune the weighting coefficients of a NMPC controller which drives the NREL 5-MW wind turbine. The results are compared with similar simulations for a manually tuned NMPC controller. Comparison verify the improved performance of the controller for weights computed with the PSO-based technique.

A Reliable Data Transmission Model for IEEE 802.15.4e Enabled Wireless Sensor Network under WiFi Interference.

PubMed

Sahoo, Prasan Kumar; Pattanaik, Sudhir Ranjan; Wu, Shih-Lin

2017-06-07

The IEEE 802.15.4e standard proposes Medium Access Control (MAC) to support collision-free wireless channel access mechanisms for industrial, commercial and healthcare applications. However, unnecessary wastage of energy and bandwidth consumption occur due to inefficient backoff management and collisions. In this paper, a new channel access mechanism is designed for the buffer constraint sensor devices to reduce the packet drop rate, energy consumption and collisions. In order to avoid collision due to the hidden terminal problem, a new frame structure is designed for the data transmission. A new superframe structure is proposed to mitigate the problems due to WiFi and ZigBee interference. A modified superframe structure with a new retransmission opportunity for failure devices is proposed to reduce the collisions and retransmission delay with high reliability. Performance evaluation and validation of our scheme indicate that the packet drop rate, throughput, reliability, energy consumption and average delay of the nodes can be improved significantly.

[Aerophagia due to noninvasive mechanical ventilation: a first manifestation of silent gastric carcinoma].

PubMed

Mayoralas Alises, S; Gómez Mendieta, M A; Díaz Lobato, S

2003-07-01

Noninvasive mechanical ventilation (NIV) techniques have proven useful in treating patients with respiratory insufficiency of various etiologies. The problems most frequently associated with this ventilatory technique are the appearance of nasal and oropharyngeal dryness, pressure sores where the nasal mask touches the skin, ocular irritation due to air leakage and epistaxis. Aerophagia appears in up to half the patients with NIV and may lead to discontinuing treatment. Drugs that accelerate gastrointestinal transit, changes in the respirator settings or changing the ventilatory modality may help to ameliorate the problem. When the symptoms arising from abdominal distension due to NIV are intense and persistent, the coexistence of an underlying abdominal pathology must be ruled out. We report the cases of two patients with these characteristics in whom gastroscopy revealed gastric carcinoma. We think that patients with persistent symptoms of aerophagia that cannot be controlled by the usual measures should undergo endoscopic exploration to rule out silent gastric disease.

A Reliable Data Transmission Model for IEEE 802.15.4e Enabled Wireless Sensor Network under WiFi Interference

PubMed Central

Sahoo, Prasan Kumar; Pattanaik, Sudhir Ranjan; Wu, Shih-Lin

2017-01-01

The IEEE 802.15.4e standard proposes Medium Access Control (MAC) to support collision-free wireless channel access mechanisms for industrial, commercial and healthcare applications. However, unnecessary wastage of energy and bandwidth consumption occur due to inefficient backoff management and collisions. In this paper, a new channel access mechanism is designed for the buffer constraint sensor devices to reduce the packet drop rate, energy consumption and collisions. In order to avoid collision due to the hidden terminal problem, a new frame structure is designed for the data transmission. A new superframe structure is proposed to mitigate the problems due to WiFi and ZigBee interference. A modified superframe structure with a new retransmission opportunity for failure devices is proposed to reduce the collisions and retransmission delay with high reliability. Performance evaluation and validation of our scheme indicate that the packet drop rate, throughput, reliability, energy consumption and average delay of the nodes can be improved significantly. PMID:28590434

Density control in ITER: an iterative learning control and robust control approach

NASA Astrophysics Data System (ADS)

Ravensbergen, T.; de Vries, P. C.; Felici, F.; Blanken, T. C.; Nouailletas, R.; Zabeo, L.

2018-01-01

Plasma density control for next generation tokamaks, such as ITER, is challenging because of multiple reasons. The response of the usual gas valve actuators in future, larger fusion devices, might be too slow for feedback control. Both pellet fuelling and the use of feedforward-based control may help to solve this problem. Also, tight density limits arise during ramp-up, due to operational limits related to divertor detachment and radiative collapses. As the number of shots available for controller tuning will be limited in ITER, in this paper, iterative learning control (ILC) is proposed to determine optimal feedforward actuator inputs based on tracking errors, obtained in previous shots. This control method can take the actuator and density limits into account and can deal with large actuator delays. However, a purely feedforward-based density control may not be sufficient due to the presence of disturbances and shot-to-shot differences. Therefore, robust control synthesis is used to construct a robustly stabilizing feedback controller. In simulations, it is shown that this combined controller strategy is able to achieve good tracking performance in the presence of shot-to-shot differences, tight constraints, and model mismatches.

Results of an integrated structure-control law design sensitivity analysis

NASA Technical Reports Server (NTRS)

Gilbert, Michael G.

1988-01-01

Next generation air and space vehicle designs are driven by increased performance requirements, demanding a high level of design integration between traditionally separate design disciplines. Interdisciplinary analysis capabilities have been developed, for aeroservoelastic aircraft and large flexible spacecraft control for instance, but the requisite integrated design methods are only beginning to be developed. One integrated design method which has received attention is based on hierarchal problem decompositions, optimization, and design sensitivity analyses. This paper highlights a design sensitivity analysis method for Linear Quadratic Cost, Gaussian (LQG) optimal control laws, which predicts change in the optimal control law due to changes in fixed problem parameters using analytical sensitivity equations. Numerical results of a design sensitivity analysis for a realistic aeroservoelastic aircraft example are presented. In this example, the sensitivity of the optimally controlled aircraft's response to various problem formulation and physical aircraft parameters is determined. These results are used to predict the aircraft's new optimally controlled response if the parameter was to have some other nominal value during the control law design process. The sensitivity results are validated by recomputing the optimal control law for discrete variations in parameters, computing the new actual aircraft response, and comparing with the predicted response. These results show an improvement in sensitivity accuracy for integrated design purposes over methods which do not include changess in the optimal control law. Use of the analytical LQG sensitivity expressions is also shown to be more efficient that finite difference methods for the computation of the equivalent sensitivity information.

An overview of the tobacco problem in India

PubMed Central

Mishra, Gauravi A.; Pimple, Sharmila A.; Shastri, Surendra S.

2012-01-01

This is a review paper comprehensively encompassing the different aspects of tobacco control with particular reference to the Indian scenario. The information on prevalent tobacco habits in India, health hazards and environmental hazards due to tobacco use, passive smoking and its impact, economics of tobacco, legislation to control tobacco in India, the tobacco cessation services and the way ahead for effective tobacco control are discussed. Tobacco is a leading preventable cause of death, killing nearly six million people worldwide each year. Reversing this entirely preventable manmade epidemic should be our top priority. This global tobacco epidemic kills more people than tuberculosis, HIV/AIDS and malaria combined. This epidemic can be resolved by becoming aware of the devastating effects of tobacco, learning about the proven effective tobacco control measures, national programmes and legislation prevailing in the home country and then engaging completely to halt the epidemic to move toward a tobacco-free world. India is the second largest consumer of tobacco globally, and accounts for approximately one-sixth of the world's tobacco-related deaths. The tobacco problem in India is peculiar, with consumption of variety of smokeless and smoking forms. Understanding the tobacco problem in India, focusing more efforts on what works and investigating the impact of sociocultural diversity and cost-effectiveness of various modalities of tobacco control should be our priority. PMID:23248419

An overview of the tobacco problem in India.

PubMed

Mishra, Gauravi A; Pimple, Sharmila A; Shastri, Surendra S

2012-07-01

This is a review paper comprehensively encompassing the different aspects of tobacco control with particular reference to the Indian scenario. The information on prevalent tobacco habits in India, health hazards and environmental hazards due to tobacco use, passive smoking and its impact, economics of tobacco, legislation to control tobacco in India, the tobacco cessation services and the way ahead for effective tobacco control are discussed. Tobacco is a leading preventable cause of death, killing nearly six million people worldwide each year. Reversing this entirely preventable manmade epidemic should be our top priority. This global tobacco epidemic kills more people than tuberculosis, HIV/AIDS and malaria combined. This epidemic can be resolved by becoming aware of the devastating effects of tobacco, learning about the proven effective tobacco control measures, national programmes and legislation prevailing in the home country and then engaging completely to halt the epidemic to move toward a tobacco-free world. India is the second largest consumer of tobacco globally, and accounts for approximately one-sixth of the world's tobacco-related deaths. The tobacco problem in India is peculiar, with consumption of variety of smokeless and smoking forms. Understanding the tobacco problem in India, focusing more efforts on what works and investigating the impact of sociocultural diversity and cost-effectiveness of various modalities of tobacco control should be our priority.

Tackling the malaria problem in the South-East Asia Region: need for a change in policy?

PubMed

Bharati, Kaushik; Ganguly, N K

2013-01-01

Malaria is largely neglected in the South-East Asia Region (SEAR), although it has the highest number of people susceptible to the disease. Malaria in the SEAR exhibits special epidemiological characteristics such as "forest malaria" and malaria due to migration across international borders. The Greater Mekong Subregion (GMS) has been a focal-point for the emergence of drug resistant malaria. With the recent emergence of artemisinin resistance, coupled with the limited availability of insecticides, malaria control efforts in the SEAR face a steep challenge. Indirect man-made factors such as climate change, as well as direct man-made factors such as the circulation of counterfeit drugs have added to the problem. Increased monitoring, surveillance, pharmacovigilance as well as cross-border collaboration are required to address these problems. Regional networking and data-sharing will keep all stakeholders updated about the status of various malaria control programmes in the SEAR. Cutting-edge technologies such as GIS/GPS (geographical information system/global positioning system) systems and mobile phones can provide information in "real-time". A holistic and sustained approach to malaria control by integrated vector management (IVM) is suggested, in which all the stakeholder countries work collaboratively as a consortium. This approach will address the malaria problem in a collective manner so that malaria control can be sustained over time.

Tackling the malaria problem in the South-East Asia Region: Need for a change in policy?

PubMed Central

Bharati, Kaushik; Ganguly, N. K.

2013-01-01

Malaria is largely neglected in the South-East Asia Region (SEAR), although it has the highest number of people susceptible to the disease. Malaria in the SEAR exhibits special epidemiological characteristics such as “forest malaria” and malaria due to migration across international borders. The Greater Mekong Subregion (GMS) has been a focal-point for the emergence of drug resistant malaria. With the recent emergence of artemisinin resistance, coupled with the limited availability of insecticides, malaria control efforts in the SEAR face a steep challenge. Indirect man-made factors such as climate change, as well as direct man-made factors such as the circulation of counterfeit drugs have added to the problem. Increased monitoring, surveillance, pharmacovigilance as well as cross-border collaboration are required to address these problems. Regional networking and data-sharing will keep all stakeholders updated about the status of various malaria control programmes in the SEAR. Cutting-edge technologies such as GIS/GPS (geographical information system/global positioning system) systems and mobile phones can provide information in “real-time”. A holistic and sustained approach to malaria control by integrated vector management (IVM) is suggested, in which all the stakeholder countries work collaboratively as a consortium. This approach will address the malaria problem in a collective manner so that malaria control can be sustained over time. PMID:23481050

Space Shuttle stability and control flight test techniques

NASA Technical Reports Server (NTRS)

Cooke, D. R.

1980-01-01

A unique approach for obtaining vehicle aerodynamic characteristics during entry has been developed for the Space Shuttle. This is due to the high cost of Shuttle testing, the need to open constraints for operational flights, and the fact that all flight regimes are flown starting with the first flight. Because of uncertainties associated with predicted aerodynamic coefficients, nine flight conditions have been identified at which control problems could occur. A detailed test plan has been developed for testing at these conditions and is presented. Due to limited testing, precise computer initiated maneuvers are implemented. These maneuvers are designed to optimize the vehicle motion for determining aerodynamic coefficients. Special sensors and atmospheric measurements are required to provide stability and control flight data during an entire entry. The techniques employed in data reduction are proven programs developed and used at NASA/DFRC.

Research on Walking Wheel Slippage Control of Live Inspection Robot

NASA Astrophysics Data System (ADS)

Yan, Yu; Liu, Xiaqing; Guo, Hao; Li, Jinliang; Liu, Lanlan

2017-07-01

To solve the problem of walking wheel slippage of a live inspection robot during walking or climbing, this paper analyzes the climbing capacity of the robot with a statics method, designs a pressing wheel mechanism, and presents a method of indirectly identifying walking wheel slippage by reading speed of the pressing wheel due to the fact that the linear speed of the pressing wheel and the walking wheel at the contract point is the same; and finds that the slippage state can not be controlled through accurate mathematical models after identifying the slippage state, whereas slippage can be controlled with fuzzy control. The experiment results indicate that due to design of the pressing wheel mechanism, friction force of the walking wheel is increased, and the climbing capability of the robot is improved. Within the range of climbing capability of the robot, gradient is the key factor that has influence on slippage of robot, and slippage can be effectively eliminated through the fuzzy control method proposed in this paper.

Pilot study of the Korean Parent Training Program using a partial group randomized experimental study

PubMed Central

Kim, Eunjung; Cain, Kevin; Boutain, Doris; Chun, Jin-Joo; Kim, Sangho; Im, Hyesang

2017-01-01

Problems Korean American (KA) children experience mental health problems due to difficulties in parenting dysfunction complicated by living in two cultures. Methods Korean Parent Training Program (KPTP) was pilot tested with 48 KA mothers of children (ages 3–8) using partial group randomized controlled experimental study design. Self-report survey and observation data were gathered. Findings Analyses using generalized estimating equation indicated the intervention group mothers increased effective parenting and their children decreased behavior problems and reported less acculturation conflict with mothers. Conclusions The KPTP is a promising way to promote effective parenting and increase positive child mental health in KA families. PMID:24645901

Community Violence Exposure and Conduct Problems in Children and Adolescents with Conduct Disorder and Healthy Controls.

PubMed

Kersten, Linda; Vriends, Noortje; Steppan, Martin; Raschle, Nora M; Praetzlich, Martin; Oldenhof, Helena; Vermeiren, Robert; Jansen, Lucres; Ackermann, Katharina; Bernhard, Anka; Martinelli, Anne; Gonzalez-Madruga, Karen; Puzzo, Ignazio; Wells, Amy; Rogers, Jack C; Clanton, Roberta; Baker, Rosalind H; Grisley, Liam; Baumann, Sarah; Gundlach, Malou; Kohls, Gregor; Gonzalez-Torres, Miguel A; Sesma-Pardo, Eva; Dochnal, Roberta; Lazaratou, Helen; Kalogerakis, Zacharias; Bigorra Gualba, Aitana; Smaragdi, Areti; Siklósi, Réka; Dikeos, Dimitris; Hervás, Amaia; Fernández-Rivas, Aranzazu; De Brito, Stephane A; Konrad, Kerstin; Herpertz-Dahlmann, Beate; Fairchild, Graeme; Freitag, Christine M; Popma, Arne; Kieser, Meinhard; Stadler, Christina

2017-01-01

Exposure to community violence through witnessing or being directly victimized has been associated with conduct problems in a range of studies. However, the relationship between community violence exposure (CVE) and conduct problems has never been studied separately in healthy individuals and individuals with conduct disorder (CD). Therefore, it is not clear whether the association between CVE and conduct problems is due to confounding factors, because those with high conduct problems also tend to live in more violent neighborhoods, i.e., an ecological fallacy. Hence, the aim of the present study was: (1) to investigate whether the association between recent CVE and current conduct problems holds true for healthy controls as well as adolescents with a diagnosis of CD; (2) to examine whether the association is stable in both groups when including effects of aggression subtypes (proactive/reactive aggression), age, gender, site and socioeconomic status (SES); and (3) to test whether proactive or reactive aggression mediate the link between CVE and conduct problems. Data from 1178 children and adolescents (62% female; 44% CD) aged between 9 years and 18 years from seven European countries were analyzed. Conduct problems were assessed using the Kiddie-Schedule of Affective Disorders and Schizophrenia diagnostic interview. Information about CVE and aggression subtypes was obtained using self-report questionnaires (Social and Health Assessment and Reactive-Proactive aggression Questionnaire (RPQ), respectively). The association between witnessing community violence and conduct problems was significant in both groups (adolescents with CD and healthy controls). The association was also stable after examining the mediating effects of aggression subtypes while including moderating effects of age, gender and SES and controlling for effects of site in both groups. There were no clear differences between the groups in the strength of the association between witnessing violence and conduct problems. However, we found evidence for a ceiling effect, i.e., individuals with very high levels of conduct problems could not show a further increase if exposed to CVE and vice versa. Results indicate that there was no evidence for an ecological fallacy being the primary cause of the association, i.e., CVE must be considered a valid risk factor in the etiology of CD.

An LMI approach for the Integral Sliding Mode and H∞ State Feedback Control Problem

NASA Astrophysics Data System (ADS)

Bezzaoucha, Souad; Henry, David

2015-11-01

This paper deals with the state feedback control problem for linear uncertain systems subject to both matched and unmatched perturbations. The proposed control law is based on an the Integral Sliding Mode Control (ISMC) approach to tackle matched perturbations as well as the H∞ paradigm for robustness against unmatched perturbations. The proposed method also parallels the work presented in [1] which addressed the same problem and proposed a solution involving an Algebraic Riccati Equation (ARE)-based formulation. The contribution of this paper is concerned by the establishment of a Linear Matrix Inequality (LMI)-based solution which offers the possibility to consider other types of constraints such as 𝓓-stability constraints (pole assignment-like constraints). The proposed methodology is applied to a pilot three-tank system and experiment results illustrate the feasibility. Note that only a few real experiments have been rarely considered using SMC in the past. This is due to the high energetic behaviour of the control signal. It is important to outline that the paper does not aim at proposing a LMI formulation of an ARE. This is done since 1971 [2] and further discussed in [3] where the link between AREs and ARIs (algebraic Riccati inequality) is established for the H∞ control problem. The main contribution of this paper is to establish the adequate LMI-based methodology (changes of matrix variables) so that the ARE that corresponds to the particular structure of the mixed ISMC/H∞ structure proposed by [1] can be re-formulated within the LMI paradigm.

Ayahuasca in adolescence: a preliminary psychiatric assessment.

PubMed

Da Silveira, Dartiu Xavier; Grob, Charles S; de Rios, Marlene Dobkin; Lopez, Enrique; Alonso, Luisa K; Tacla, Cristiane; Doering-Silveira, Evelyn

2005-06-01

Ayahuasca is believed to be harmless for those (including adolescents) drinking it within a religious setting. Nevertheless controlled studies on the mental/ psychiatric status of ritual hallucinogenic ayahuasca concoction consumers are still lacking. In this study, 40 adolescents from a Brazilian ayahuasca sect were compared with 40 controls matched on sex, age, and educational background for psychiatric symptomatology. Screening scales for depression, anxiety, alcohol consumption patterns (abuse), attentional problems, and body dysmorphic disorders were used. It was found that, compared to controls, considerable lower frequencies of positive scoring for anxiety, body dismorphism, and attentional problems were detected among ayahuasca-using adolescents despite overall similar psychopathological profiles displayed by both study groups. Low frequencies of psychiatric symptoms detected among adolescents consuming ayahuasca within a religious context may reflect a protective effect due to their religious affiliation. However further studies on the possible interference of other variables in the outcome are necessary.

A Functional Subnetwork Approach to Designing Synthetic Nervous Systems That Control Legged Robot Locomotion

PubMed Central

Szczecinski, Nicholas S.; Hunt, Alexander J.; Quinn, Roger D.

2017-01-01

A dynamical model of an animal’s nervous system, or synthetic nervous system (SNS), is a potentially transformational control method. Due to increasingly detailed data on the connectivity and dynamics of both mammalian and insect nervous systems, controlling a legged robot with an SNS is largely a problem of parameter tuning. Our approach to this problem is to design functional subnetworks that perform specific operations, and then assemble them into larger models of the nervous system. In this paper, we present networks that perform addition, subtraction, multiplication, division, differentiation, and integration of incoming signals. Parameters are set within each subnetwork to produce the desired output by utilizing the operating range of neural activity, R, the gain of the operation, k, and bounds based on biological values. The assembly of large networks from functional subnetworks underpins our recent results with MantisBot. PMID:28848419

Enhancing the stabilization of aircraft pitch motion control via intelligent and classical method

NASA Astrophysics Data System (ADS)

Lukman, H.; Munawwarah, S.; Azizan, A.; Yakub, F.; Zaki, S. A.; Rasid, Z. A.

2017-12-01

The pitching movement of an aircraft is very important to ensure passengers are intrinsically safe and the aircraft achieve its maximum stability. The equations governing the motion of an aircraft are a complex set of six nonlinear coupled differential equations. Under certain assumptions, it can be decoupled and linearized into longitudinal and lateral equations. Pitch control is a longitudinal problem and thus, only the longitudinal dynamics equations are involved in this system. It is a third order nonlinear system, which is linearized about the operating point. The system is also inherently unstable due to the presence of a free integrator. Because of this, a feedback controller is added in order to solve this problem and enhance the system performance. This study uses two approaches in designing controller: a conventional controller and an intelligent controller. The pitch control scheme consists of proportional, integral and derivatives (PID) for conventional controller and fuzzy logic control (FLC) for intelligent controller. Throughout the paper, the performance of the presented controllers are investigated and compared based on the common criteria of step response. Simulation results have been obtained and analysed by using Matlab and Simulink software. The study shows that FLC controller has higher ability to control and stabilize the aircraft's pitch angle as compared to PID controller.

Effectiveness of a coordinated and tailored return-to-work intervention for sickness absence beneficiaries with mental health problems.

PubMed

Martin, Marie H T; Nielsen, Maj Britt D; Madsen, Ida E H; Petersen, Signe M A; Lange, Theis; Rugulies, Reiner

2013-12-01

Sickness absence and exclusion from the labour market due to mental health problems (MHPs) is a growing concern in many countries. Knowledge about effective return-to-work (RTW) intervention models is still limited, but a multidisciplinary, coordinated and tailored approach has shown promising results in the context of musculoskeletal disorders. The purpose of this study was to assess the effectiveness of this approach as implemented among sickness absence beneficiaries with MHPs. In a quasi-randomised, controlled trial, we assessed the intervention's effect in terms of time to RTW and labour market status after 1 year. We used two different analytical strategies to compare time to RTW between participants receiving the intervention (n = 88) and those receiving conventional case management (n = 80): (1) a traditional multivariable regression analysis controlling for measured confounding, and (2) an instrumental variable (IV) analysis controlling for unmeasured confounding. The two analytical approaches provided similar results in terms of a longer time to RTW among recipients of the intervention (HR = 0.50; 95 % CI 0.34-0.75), although the estimate provided by the IV-analysis was non-significant (HR = 0.70; 95 % CI 0.23-2.12). After 1 year, more recipients of the intervention than of conventional case management were receiving sickness absence benefits (p = 0.031). The intervention delayed RTW compared to conventional case management, after accounting for measured confounding. The delayed RTW may be due to either implementation or program failure, or both. It may also reflect the complexity of retaining employees with mental health problems in the workplace.

Adaptive control strategies for flexible robotic arm

NASA Technical Reports Server (NTRS)

Bialasiewicz, Jan T.

1993-01-01

The motivation of this research came about when a neural network direct adaptive control scheme was applied to control the tip position of a flexible robotic arm. Satisfactory control performance was not attainable due to the inherent non-minimum phase characteristics of the flexible robotic arm tip. Most of the existing neural network control algorithms are based on the direct method and exhibit very high sensitivity if not unstable closed-loop behavior. Therefore a neural self-tuning control (NSTC) algorithm is developed and applied to this problem and showed promising results. Simulation results of the NSTC scheme and the conventional self-tuning (STR) control scheme are used to examine performance factors such as control tracking mean square error, estimation mean square error, transient response, and steady state response.

Attention problems, inhibitory control, and intelligence index overlapping genetic factors: a study in 9-, 12-, and 18-year-old twins.

PubMed

Polderman, Tinca J C; de Geus, Eco J C; Hoekstra, Rosa A; Bartels, Meike; van Leeuwen, Marieke; Verhulst, Frank C; Posthuma, Danielle; Boomsma, Dorret I

2009-05-01

It is assumed that attention problems (AP) are related to impaired executive functioning. We investigated the association between AP and inhibitory control and tested to what extent the association was due to genetic factors shared with IQ. Data were available from 3 independent samples of 9-, 12-, and 18-year-old twins and their siblings (1,209 participants). AP were assessed with checklists completed by multiple informants. Inhibitory control was measured with the Stroop Color Word Task (Stroop, 1935), and IQ with the Wechsler Intelligence Scale for Children (Wechsler et al., 2002) or Wechsler Adult Intelligence Scale (Wechsler, 1997). AP and inhibitory control were only correlated in the 12-year-old cohort (r = .18), but appeared non-significant after controlling for IQ. Significant correlations existed between AP and IQ in 9- and 12-year olds (r = -.26/-.34). Inhibitory control and IQ were correlated in all cohorts (r = -.16, -.24 and -.35, respectively). Genetic factors that influenced IQ also influenced inhibitory control. We conclude that the association between AP and inhibitory control as reported in the literature may largely derive from genetic factors that are shared with IQ.

Solution-focused intervention for sick listed employees with psychological problems or muscle skeletal pain: a randomised controlled trial [ISRCTN39140363

PubMed Central

Nystuen, Pal; Hagen, Kare B

2006-01-01

Background Long-term sick leave has been of concern to politicians and decision-makers in Norway for several years. In the current study we assess the efficacy of a solution-focused follow-up for sick-listed employees. Methods Employees on long-term sick leave due to psychological problems or muscle skeletal pain (n = 703) were invited to participate in the project. Following self-recruitment, 103 were randomly allocated to receive solution-focused follow-up (n = 53) or "treatment as usual" (n = 50). The intervention was integrated within the regular follow up of six social security offices and organised as eight weekly solution focused work sessions. Effectiveness was measured by rate of return to work and health related quality of life (SF-36). Results Intention to treat analysis showed no significant differences between the two groups for any of the outcome measures. Secondary analysis, comparing those who attended at least 50% of the sessions with the control group revealed a significant difference in favour of the active intervention group in the SF-36 subscale of mental health (Effect Size 0.56, p = 0.05). When comparing the subgroup of participants with psychological problems there was a significant difference in mental health in favour of the intervention group (Effect Size 0.71, p = 0.041). Conclusion A voluntary solution-focused intervention offered by social-security offices is no more effective than regular follow up for employees on long-term sick leave due to psychological problems or muscle skeletal pain. PMID:16542443

Modeling human response errors in synthetic flight simulator domain

NASA Technical Reports Server (NTRS)

Ntuen, Celestine A.

1992-01-01

This paper presents a control theoretic approach to modeling human response errors (HRE) in the flight simulation domain. The human pilot is modeled as a supervisor of a highly automated system. The synthesis uses the theory of optimal control pilot modeling for integrating the pilot's observation error and the error due to the simulation model (experimental error). Methods for solving the HRE problem are suggested. Experimental verification of the models will be tested in a flight quality handling simulation.

[Secretion of growth hormone in hyperthyroidism].

PubMed

Hervás, F; Morreale de Escobar, G; Escobar Del Rey, F; Pozuelo, V

1976-01-01

The authors studied growth hormone (GH) secretion in a group of adult controls and another group of hyperthyroid patients after stimulation with intravenous insulin-induced (0,1 IU/kg) hypoglycemia, aiming to clear out the problem of discrepancies in literature concerning GH secretion in hyperthyroidism. They concluded that in this syndrome, GH levels are significantly higher than those of controls. The GH releasing response is normal, though it could be expected to be decreased due to decreased pituitary GH contents as a result of permanent somatotrophic cell stimulation.

Accuracy of self-reported medical problems in patients with alcohol dependence and co-occurring schizophrenia or schizoaffective disorder.

PubMed

Meszaros, Zsuzsa Szombathyne; Dimmock, Jacqueline A; Ploutz-Snyder, Robert; Chauhan, Sumerendra Vir Singh; Abdul-Malak, Ynesse; Middleton, Frank A; Batki, Steven L

2011-11-01

Schizophrenia and alcohol dependence (AD) are both major risk factors for a variety of medical problems, yet little is known about the medical status of patients in whom both conditions coexist. The objectives of this study are to assess accuracy of self-reported medical problems and to compare the accuracy reports in patients with schizophrenia or schizoaffective disorder and co-occurring AD compared to patients with AD only and to controls. Our hypothesis was that medical problems are under-reported in patients with co-occurring disorders, possibly due to the combination of alcohol use and symptoms of schizophrenia. Self-reported medical diagnoses were recorded and compared to medical records obtained from all area hospitals in 42 patients with schizophrenia and AD, 44 patients with schizoaffective disorder and AD, 41 patients with AD only, and 15 control subjects. Patients underwent medical history, physical examination, and review of medical records. Patients with schizophrenia or schizoaffective disorder and co-occurring AD underreported their medical problems significantly more than patients with AD only and controls. Accuracy of self report was significantly lower in patients with schizophrenia-spectrum disorders plus co-occurring alcohol dependence than in AD alone or in controls. The most commonly underreported diagnoses included coronary artery disease, chronic renal failure, seizure disorder, hyperlipidemia, asthma and hypertension. In order to detect potentially unreported medical conditions in patients with co-occurring schizophrenia/schizoaffective disorder and alcohol dependence, the use of targeted screening questionnaires is recommended in addition to physical examination and thorough review of medical records. Copyright © 2011 Elsevier B.V. All rights reserved.

Save Me from Myself: College Students' Fears of Losing Control and Acting Violently

ERIC Educational Resources Information Center

Hayes, Jeffrey A.; Crane, Amy L.; Locke, Benjamin D.

2010-01-01

Violent behavior on college campuses has been a long-standing problem that has received increased attention due to recent shootings. At present, the factors that predict college students' violent behavior are not well understood. To increase knowledge in this area, two studies were conducted that examined the prevalence and predictors of college…

The Real Cutting Edge in Education: Changing Misbehaving Students in the Classroom and School.

ERIC Educational Resources Information Center

Rancifer, Jesse L.

This paper examines techniques for dealing with behavior problems in students. The Bill of Rights and the 14th Amendment protect individuals' rights and must be considered in developing effective punitive consequences to control misbehaving students. Due process must be practiced in handling disciplinary sanctions. Principals and teachers can use…

Dynamic analysis of space-related linear and non-linear structures

NASA Technical Reports Server (NTRS)

Bosela, Paul A.; Shaker, Francis J.; Fertis, Demeter G.

1990-01-01

In order to be cost effective, space structures must be extremely light weight, and subsequently, very flexible structures. The power system for Space Station Freedom is such a structure. Each array consists of a deployable truss mast and a split blanket of photo-voltaic solar collectors. The solar arrays are deployed in orbit, and the blanket is stretched into position as the mast is extended. Geometric stiffness due to the preload make this an interesting non-linear problem. The space station will be subjected to various dynamic loads, during shuttle docking, solar tracking, attitude adjustment, etc. Accurate prediction of the natural frequencies and mode shapes of the space station components, including the solar arrays, is critical for determining the structural adequacy of the components, and for designing a dynamic control system. The process used in developing and verifying the finite element dynamic model of the photo-voltaic arrays is documented. Various problems were identified, such as grounding effects due to geometric stiffness, large displacement effects, and pseudo-stiffness (grounding) due to lack of required rigid body modes. Analysis techniques, such as development of rigorous solutions using continuum mechanics, finite element solution sequence altering, equivalent systems using a curvature basis, Craig-Bampton superelement approach, and modal ordering schemes were utilized. The grounding problems associated with the geometric stiffness are emphasized.

Dynamic analysis of space-related linear and non-linear structures

NASA Technical Reports Server (NTRS)

Bosela, Paul A.; Shaker, Francis J.; Fertis, Demeter G.

1990-01-01

In order to be cost effective, space structures must be extremely light weight, and subsequently, very flexible structures. The power system for Space Station Freedom is such a structure. Each array consists of a deployable truss mast and a split blanket of photovoltaic solar collectors. The solar arrays are deployed in orbit, and the blanket is stretched into position as the mast is extended. Geometric stiffness due to the preload make this an interesting non-linear problem. The space station will be subjected to various dynamic loads, during shuttle docking, solar tracking, attitude adjustment, etc. Accurate prediction of the natural frequencies and mode shapes of the space station components, including the solar arrays, is critical for determining the structural adequacy of the components, and for designing a dynamic controls system. The process used in developing and verifying the finite element dynamic model of the photo-voltaic arrays is documented. Various problems were identified, such as grounding effects due to geometric stiffness, large displacement effects, and pseudo-stiffness (grounding) due to lack of required rigid body modes. Analysis techniques, such as development of rigorous solutions using continuum mechanics, finite element solution sequence altering, equivalent systems using a curvature basis, Craig-Bampton superelement approach, and modal ordering schemes were utilized. The grounding problems associated with the geometric stiffness are emphasized.

Energy dissipation in a friction-controlled slide of a body excited by random motions of the foundation

NASA Astrophysics Data System (ADS)

Berezin, Sergey; Zayats, Oleg

2018-01-01

We study a friction-controlled slide of a body excited by random motions of the foundation it is placed on. Specifically, we are interested in such quantities as displacement, traveled distance, and energy loss due to friction. We assume that the random excitation is switched off at some time (possibly infinite) and show that the problem can be treated in an analytic, explicit, manner. Particularly, we derive formulas for the moments of the displacement and distance, and also for the average energy loss. To accomplish that we use the Pugachev-Sveshnikov equation for the characteristic function of a continuous random process given by a system of SDEs. This equation is solved by reduction to a parametric Riemann boundary value problem of complex analysis.

[Quality control in anesthesiology].

PubMed

Muñoz-Ramón, J M

1995-03-01

The process of quality control and auditing of anesthesiology allows us to evaluate care given by a service and solve problems that are detected. Quality control is a basic element of care giving and is only secondarily an area of academic research; it is therefore a meaningless effort if the information does not serve to improve departmental procedures. Quality assurance procedures assume certain infrastructural requirements and an initial period of implementation and adjustment. The main objectives of quality control are the reduction of morbidity and mortality due to anesthesia, assurance of the availability and proper management of resources and, finally, the well-being and safety of the patient.

Spectral and non-spectral interferences in the determination of thallium in environmental materials using electrothermal atomization and vaporization techniques—a case study

NASA Astrophysics Data System (ADS)

Vale, Maria Goreti R.; Welz, Bernhard

2002-12-01

The literature on the determination of Tl in environmental samples using electrothermal atomization (ETA) and vaporization (ETV) techniques has been reviewed with special attention devoted to potential interferences and their control. Chloride interference, which is due to the formation of the volatile monochloride in the condensed phase, is the most frequently observed problem. Due to its high dissociation energy (88 kcal/mol), TlCl is difficult to dissociate in the gas phase and is easily lost. The best means of controlling this interference in ETA is atomization under isothermal conditions according to the stabilized temperature platform furnace concept, and the use of reduced palladium as a modifier. An alternative approach appears to be the 'fast furnace' concept, wherein both the use of a modifier and the pyrolysis stage are omitted. This concept requires an efficient background correction system, and high-resolution continuum-source atomic absorption spectrometry (HR-CS AAS) appears to offer the best results. This chloride interference can also cause significant problems when ETV techniques are used. Among the spectral interferences found in the determination of thallium are those due to Pd, the most efficient modifier, and Fe, which is frequently found at high concentrations in environmental samples. Both interferences are due to nearby atomic lines, and are observed only when deuterium background correction and relatively high atomization temperatures are used. A more serious spectral interference is that due to the molecular absorption spectrum of SO 2, which has a maximum around the Tl line and exhibits a pronounced rotational fine structure. HR-CS AAS again showed the best performance in coping with this interference.

Design of sewage treatment system by applying fuzzy adaptive PID controller

NASA Astrophysics Data System (ADS)

Jin, Liang-Ping; Li, Hong-Chan

2013-03-01

In the sewage treatment system, the dissolved oxygen concentration control, due to its nonlinear, time-varying, large time delay and uncertainty, is difficult to establish the exact mathematical model. While the conventional PID controller only works with good linear not far from its operating point, it is difficult to realize the system control when the operating point far off. In order to solve the above problems, the paper proposed a method which combine fuzzy control with PID methods and designed a fuzzy adaptive PID controller based on S7-300 PLC .It employs fuzzy inference method to achieve the online tuning for PID parameters. The control algorithm by simulation and practical application show that the system has stronger robustness and better adaptability.

Fractional Order PIλDμ Control for Maglev Guiding System

NASA Astrophysics Data System (ADS)

Hu, Qing; Hu, Yuwei

To effectively suppress the external disturbances and parameter perturbation problem of the maglev guiding system, and improve speed and robustness, the electromagnetic guiding system is exactly linearized using state feedback method, Fractional calculus theory is introduced, the order of integer order PID control was extended to the field of fractional, then fractional order PIλDμ Controller was presented, Due to the extra two adjustable parameters compared with traditional PID controller, fractional order PIλDμ controllers were expected to show better control performance. The results of the computer simulation show that the proposed controller suppresses the external disturbances and parameter perturbation of the system effectively; the system response speed was increased; at the same time, it had flexible structure and stronger robustness.

Anti-windup adaptive PID control design for a class of uncertain chaotic systems with input saturation.

PubMed

Tahoun, A H

2017-01-01

In this paper, the stabilization problem of actuators saturation in uncertain chaotic systems is investigated via an adaptive PID control method. The PID control parameters are auto-tuned adaptively via adaptive control laws. A multi-level augmented error is designed to account for the extra terms appearing due to the use of PID and saturation. The proposed control technique uses both the state-feedback and the output-feedback methodologies. Based on Lyapunov׳s stability theory, new anti-windup adaptive controllers are proposed. Demonstrative examples with MATLAB simulations are studied. The simulation results show the efficiency of the proposed adaptive PID controllers. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Subsonic stability and control flight test results of the Space Shuttle /tail cone off/

NASA Technical Reports Server (NTRS)

Cooke, D. R.

1980-01-01

The subsonic stability and control testing of the Space Shuttle Orbiter in its two test flights in the tailcone-off configuration is discussed, and test results are presented. Flight test maneuvers were designed to maximize the quality and quantity of stability and control data in the minimal time allotted using the Space Shuttle Functional Simulator and the Modified Maximum Likelihood Estimator (MMLE) programs, and coefficients were determined from standard sensor data sets using the MMLE, despite problems encountered in timing due to the different measurement systems used. Results are included for lateral directional and longitudinal maneuvers as well as the Space Shuttle aerodynamic data base obtained using the results of wind tunnel tests. The flight test data are found to permit greater confidence in the data base since the differences found are well within control system capability. It is suggested that the areas of major differences, including lateral directional data with open speedbrake, roll due to rudder and normal force due to elevon, be investigated in any further subsonic flight testing. Improvements in sensor data and data handling techniques for future orbital test flights are indicated.

Robust intelligent flight control for hypersonic vehicles. Ph.D. Thesis - Massachusetts Inst. of Technology

NASA Technical Reports Server (NTRS)

Chamitoff, Gregory Errol

1992-01-01

Intelligent optimization methods are applied to the problem of real-time flight control for a class of airbreathing hypersonic vehicles (AHSV). The extreme flight conditions that will be encountered by single-stage-to-orbit vehicles, such as the National Aerospace Plane, present a tremendous challenge to the entire spectrum of aerospace technologies. Flight control for these vehicles is particularly difficult due to the combination of nonlinear dynamics, complex constraints, and parametric uncertainty. An approach that utilizes all available a priori and in-flight information to perform robust, real time, short-term trajectory planning is presented.

"Exercise dependence"--a problem or natural result of high activity?

PubMed

Phelan, Suzanne; Bond, Dale S; Lang, Wei; Jordan, Dustin; Wing, Rena R

2011-11-01

To compare physical activity (PA) and exercise dependence (ED) in 267 weight-loss maintainers (WLM) and 213 normal-weight (NW) controls. PA and ED assessed via accelerometery and the Exercise Dependence Questionnaire. WLM had higher PA levels and ED scores than those of NW (P< 0.0001). WLM status (P=.006) and higher PA (P=.0001) were independently related to higher ED, although effect sizes were larger for PA. Exercising for weight control was the ED domain that most discriminated WLM from NW. WLM have higher ED scores than do NW, but this is mostly due to exercising for weight control.

Factors influencing post abortion outcomes among high-risk patients in Zimbabwe.

PubMed

Mudokwenuy-Rawdon, C; Ehlers, V J; Bezuidenhout, M C

2005-11-01

Post abortion complications remain one of the major causes of mortality among women of child bearing age in Zimbabwe. Based on this problem, factors associated with mortalities due to abortion were investigated with the aim of improving post abortion outcomes for Zimbabwe's women, and possibly also for women of other African countries. Cases and controls were selected from 4895 post abortion records to conduct a retrospective case-control study. Significant risk factors identified for reducing mortalities due to post abortion complications included the administration of oxytocic drugs and evacuation of the uterus whilst anaemia and sepsis apparently reduced these women's chances of survival. Women who died (cases) from post abortion complications apparently received better reported quantitative care than controls. Recommendations based on this research report include improved education of health care workers and enhanced in-service training, regular audits of patients' records and changed policies for managing these conditions more effectively in Zimbabwe.

Self-control of traffic lights and vehicle flows in urban road networks

NASA Astrophysics Data System (ADS)

Lämmer, Stefan; Helbing, Dirk

2008-04-01

Based on fluid-dynamic and many-particle (car-following) simulations of traffic flows in (urban) networks, we study the problem of coordinating incompatible traffic flows at intersections. Inspired by the observation of self-organized oscillations of pedestrian flows at bottlenecks, we propose a self-organization approach to traffic light control. The problem can be treated as a multi-agent problem with interactions between vehicles and traffic lights. Specifically, our approach assumes a priority-based control of traffic lights by the vehicle flows themselves, taking into account short-sighted anticipation of vehicle flows and platoons. The considered local interactions lead to emergent coordination patterns such as 'green waves' and achieve an efficient, decentralized traffic light control. While the proposed self-control adapts flexibly to local flow conditions and often leads to non-cyclical switching patterns with changing service sequences of different traffic flows, an almost periodic service may evolve under certain conditions and suggests the existence of a spontaneous synchronization of traffic lights despite the varying delays due to variable vehicle queues and travel times. The self-organized traffic light control is based on an optimization and a stabilization rule, each of which performs poorly at high utilizations of the road network, while their proper combination reaches a superior performance. The result is a considerable reduction not only in the average travel times, but also of their variation. Similar control approaches could be applied to the coordination of logistic and production processes.

Neural Approximation-Based Adaptive Control for a Class of Nonlinear Nonstrict Feedback Discrete-Time Systems.

PubMed

Yan-Jun Liu; Shu Li; Shaocheng Tong; Chen, C L Philip

2017-07-01

In this paper, an adaptive control approach-based neural approximation is developed for a class of uncertain nonlinear discrete-time (DT) systems. The main characteristic of the considered systems is that they can be viewed as a class of multi-input multioutput systems in the nonstrict feedback structure. The similar control problem of this class of systems has been addressed in the past, but it focused on the continuous-time systems. Due to the complicacies of the system structure, it will become more difficult for the controller design and the stability analysis. To stabilize this class of systems, a new recursive procedure is developed, and the effect caused by the noncausal problem in the nonstrict feedback DT structure can be solved using a semirecurrent neural approximation. Based on the Lyapunov difference approach, it is proved that all the signals of the closed-loop system are semiglobal, ultimately uniformly bounded, and a good tracking performance can be guaranteed. The feasibility of the proposed controllers can be validated by setting a simulation example.

Optimal Control of Hybrid Systems in Air Traffic Applications

NASA Astrophysics Data System (ADS)

Kamgarpour, Maryam

Growing concerns over the scalability of air traffic operations, air transportation fuel emissions and prices, as well as the advent of communication and sensing technologies motivate improvements to the air traffic management system. To address such improvements, in this thesis a hybrid dynamical model as an abstraction of the air traffic system is considered. Wind and hazardous weather impacts are included using a stochastic model. This thesis focuses on the design of algorithms for verification and control of hybrid and stochastic dynamical systems and the application of these algorithms to air traffic management problems. In the deterministic setting, a numerically efficient algorithm for optimal control of hybrid systems is proposed based on extensions of classical optimal control techniques. This algorithm is applied to optimize the trajectory of an Airbus 320 aircraft in the presence of wind and storms. In the stochastic setting, the verification problem of reaching a target set while avoiding obstacles (reach-avoid) is formulated as a two-player game to account for external agents' influence on system dynamics. The solution approach is applied to air traffic conflict prediction in the presence of stochastic wind. Due to the uncertainty in forecasts of the hazardous weather, and hence the unsafe regions of airspace for aircraft flight, the reach-avoid framework is extended to account for stochastic target and safe sets. This methodology is used to maximize the probability of the safety of aircraft paths through hazardous weather. Finally, the problem of modeling and optimization of arrival air traffic and runway configuration in dense airspace subject to stochastic weather data is addressed. This problem is formulated as a hybrid optimal control problem and is solved with a hierarchical approach that decouples safety and performance. As illustrated with this problem, the large scale of air traffic operations motivates future work on the efficient implementation of the proposed algorithms.

Family environment and psychopathology in offspring of parents with bipolar disorder.

PubMed

Lau, Phoebe; Hawes, David J; Hunt, Caroline; Frankland, Andrew; Roberts, Gloria; Wright, Adam; Costa, Daniel S J; Mitchell, Philip B

2018-01-15

The aim of this study was to examine the relationship between family environment (cohesion and parental bonding), high-risk status, and psychopathology (internalizing and externalizing problems) among offspring of parents with bipolar disorder (BD), from the perspective of both offspring and their parents. We further tested if family environment mediated the relationship between bipolar risk status and internalizing and externalizing problems. High-risk (n = 90) BD offspring and control (n = 56) offspring aged 12-21 years old, and their parents, completed questionnaires on family cohesion and offspring internalizing and externalizing problems. Offspring also completed a parental bonding questionnaire. Group differences were examined, followed by multi-level mediation analysis with maximum likelihood and robust standard errors. Both offspring and parents in the high-risk group reported higher levels of internalizing and externalizing problems than controls. According to offspring reports, high-risk status, lower maternal and paternal care in parental bonding, was independently associated with internalizing problems. Lower maternal care alone predicted externalizing problems. Family environment did not mediate the relationship between bipolar risk status, and offspring problems. Due to rates of missing data from parent reports of offspring psychopathology, mediation analysis was completed using offspring reports. The offspring-report data presented indicate that low parental warmth and connection were associated with internalizing and externalizing problems as an independent risk factor, in addition to bipolar risk status. The parent-child relationship therefore warrants attention as a potential target for prevention strategies with such families. Copyright © 2017 Elsevier B.V. All rights reserved.

Orbiting space debris: Dangers, measurement and mitigation

NASA Astrophysics Data System (ADS)

McNutt, Ross T.

1992-06-01

Space debris is a growing environmental problem. Accumulation of objects in earth orbit threatens space systems through the possibility of collisions and runaway debris multiplication. The amount of debris in orbit is uncertain due to the lack of information on the population of debris between 1 and 10 centimeters diameter. Collisions with debris even smaller than 1 cm can be catastrophic due to the high orbital velocities involved. Research efforts are under way at NASA, United States Space Command and the Air Force Phillips Laboratory to detect and catalog the debris population in near-earth space. Current international and national laws are inadequate to control the proliferation of space debris. Space debris is a serious problem with large economic, military, technical and diplomatic components. Actions need to be taken now to: determine the full extent of the orbital debris problem; accurately predict the future evolution of the debris population; decide the extent of the debris mitigation procedures required; implement these policies on a global basis via an international treaty. Action must be initiated now, before the loss of critical space systems such as the space shuttle or the space station.

Organic and Nonorganic Feeding Disorders.

PubMed

Rybak, Anna

2015-01-01

Feeding is one of the most important interactions between caregiver and child in the first few years of life and even later on in handicapped children. Feeding disorders can present as food refusal or low quantity of food intake due to behavioral issues or underlying organic conditions. This situation concerns mostly infants and children below 6 years of age; however, feeding problems can appear also later on in life. Feeding disorders are a concern for over 10-25% of parents of otherwise healthy children below 3 years of age, but only 1-5% of infants and toddlers suffer from severe feeding problems resulting in failure to thrive. In case of premature infants or neurologically disabled children, this rate is much higher. Feeding disorders may appear as an isolated problem, mainly due to negative behaviors during feeding, or as a concomitant disorder with an underlying organic disease or structural anomaly. The newest classification also includes the feeding style presented by the caregiver (responsive, controlling, indulgent or neglectful) as a separate cause of feeding disorders. © 2015 S. Karger AG, Basel.

Information needs related to extension service and community outreach.

PubMed

Bottcher, Robert W

2003-06-01

Air quality affects everyone. Some people are affected by air quality impacts, regulations, and technological developments in several ways. Stakeholders include the medical community, ecologists, government regulators, industries, technology providers, academic professionals, concerned citizens, the news media, and elected officials. Each of these groups may perceive problems and opportunities differently, but all need access to information as it is developed. The diversity and complexity of air quality problems contribute to the challenges faced by extension and outreach professionals who must communicate with stakeholders having diverse backgrounds. Gases, particulates, biological aerosols, pathogens, and odors all require expensive and relatively complex technology to measure and control. Economic constraints affect the ability of regulators and others to measure air quality, and industry and others to control it. To address these challenges, while communicating air quality research results and concepts to stakeholders, three areas of information needs are evident. (1) A basic understanding of the fundamental concepts regarding air pollutants and their measurement and control is needed by all stakeholders; the Extension Specialist, to be effective, must help people move some distance up the learning curve. (2) Each problem or set of problems must be reasonably well defined since comprehensive solution of all problems simultaneously may not be feasible; for instance, the solution of an odor problem associated with animal production may not address atmospheric effects due to ammonia emissions. (3) The integrity of the communication process must be preserved by avoiding prejudice and protectionism; although stakeholders may seek to modify information to enhance their interests, extension and outreach professionals must be willing to present unwelcome information or admit to a lack of information. A solid grounding in fundamental concepts, careful and fair problem definition, and a resolute commitment to integrity and credibility will enable effective communication of air quality information to and among diverse stakeholders.

Executive Function and Internalizing Symptoms in Adolescents and Young Adults With Congenital Heart Disease: The Role of Coping.

PubMed

Jackson, Jamie L; Gerardo, Gina M; Monti, Jennifer D; Schofield, Kyle A; Vannatta, Kathryn

2018-01-10

Executive functioning deficits have been documented among congenital heart disease (CHD) survivors and may contribute to emotional distress. Little research has investigated the role of coping in this association. This study examined the role of coping in accounting for the association between self-reported executive function problems and internalizing symptoms among adolescents and emerging adults (AEAs), as well as young adults (YAs) with CHD. Participants included 74 AEA ( M age  = 19.32  ±  3.47 years, range 15-25 years) and 98 YA CHD survivors ( M age  = 32.00  ±  3.69 years, range 26-39 years), recruited from pediatric and adult outpatient cardiology clinics. Participants completed self-report measures of executive function problems, coping (primary control, secondary control, and disengagement coping), and internalizing symptoms. Lesion severity classification and functional impairment due to symptoms of heart failure were determined from medical chart review. Significant problems in executive function were reported by 5% of AEA and 13% of YA. Coping was not associated with executive function problems or internalizing symptoms for AEA. However, among YA, less use of adaptive coping strategies and more maladaptive coping responses was associated with both more executive function problems and internalizing symptoms. An indirect effect of executive function problems on internalizing symptoms via secondary control coping emerged for YA. Executive function problems may disrupt the ability to use important adaptive coping skills, such as cognitive reappraisal, positive thinking, and acceptance, thereby resulting in greater emotional distress among YA CHD survivors. © The Author(s) 2018. Published by Oxford University Press on behalf of the Society of Pediatric Psychology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Flow microreactor synthesis in organo-fluorine chemistry

PubMed Central

Nagaki, Aiichiro

2013-01-01

Summary Organo-fluorine compounds are the substances of considerable interest in various industrial fields due to their unique physical and chemical properties. Despite increased demand in wide fields of science, synthesis of fluoro-organic compounds is still often faced with problems such as the difficulties in handling of fluorinating reagents and in controlling of chemical reactions. Recently, flow microreactor synthesis has emerged as a new methodology for producing chemical substances with high efficiency. This review outlines the successful examples of synthesis and reactions of fluorine-containing molecules by the use of flow microreactor systems to overcome long-standing problems in fluorine chemistry. PMID:24367443

Flow microreactor synthesis in organo-fluorine chemistry.

PubMed

Amii, Hideki; Nagaki, Aiichiro; Yoshida, Jun-Ichi

2013-12-05

Organo-fluorine compounds are the substances of considerable interest in various industrial fields due to their unique physical and chemical properties. Despite increased demand in wide fields of science, synthesis of fluoro-organic compounds is still often faced with problems such as the difficulties in handling of fluorinating reagents and in controlling of chemical reactions. Recently, flow microreactor synthesis has emerged as a new methodology for producing chemical substances with high efficiency. This review outlines the successful examples of synthesis and reactions of fluorine-containing molecules by the use of flow microreactor systems to overcome long-standing problems in fluorine chemistry.

A study of volatile contaminants in recovered water

NASA Technical Reports Server (NTRS)

Mckee, H. C.; Marek, R., Jr.

1972-01-01

The recovery and reuse of water during long term space flight is discussed. Particular attention was given to obtaining basic information on the volatile impurities in urine samples and in water recovered from urine by distillation. Data also cover laboratory distillation tests to determine the nature and extent of volatile constituents in the distillate and an evaluation of possible problems in distillation due to iodine used for control of microbial contamination. Efforts made to develop design criteria for distillation equipment to minimize the problems of volatile contaminants various methods which might be used for purification subsequent to recovery are included.

Massively parallel algorithms for real-time wavefront control of a dense adaptive optics system

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

Fijany, A.; Milman, M.; Redding, D.

1994-12-31

In this paper massively parallel algorithms and architectures for real-time wavefront control of a dense adaptive optic system (SELENE) are presented. The authors have already shown that the computation of a near optimal control algorithm for SELENE can be reduced to the solution of a discrete Poisson equation on a regular domain. Although, this represents an optimal computation, due the large size of the system and the high sampling rate requirement, the implementation of this control algorithm poses a computationally challenging problem since it demands a sustained computational throughput of the order of 10 GFlops. They develop a novel algorithm,more » designated as Fast Invariant Imbedding algorithm, which offers a massive degree of parallelism with simple communication and synchronization requirements. Due to these features, this algorithm is significantly more efficient than other Fast Poisson Solvers for implementation on massively parallel architectures. The authors also discuss two massively parallel, algorithmically specialized, architectures for low-cost and optimal implementation of the Fast Invariant Imbedding algorithm.« less

A multimodal interface to resolve the Midas-Touch problem in gaze controlled wheelchair.

PubMed

Meena, Yogesh Kumar; Cecotti, Hubert; Wong-Lin, KongFatt; Prasad, Girijesh

2017-07-01

Human-computer interaction (HCI) research has been playing an essential role in the field of rehabilitation. The usability of the gaze controlled powered wheelchair is limited due to Midas-Touch problem. In this work, we propose a multimodal graphical user interface (GUI) to control a powered wheelchair that aims to help upper-limb mobility impaired people in daily living activities. The GUI was designed to include a portable and low-cost eye-tracker and a soft-switch wherein the wheelchair can be controlled in three different ways: 1) with a touchpad 2) with an eye-tracker only, and 3) eye-tracker with soft-switch. The interface includes nine different commands (eight directions and stop) and integrated within a powered wheelchair system. We evaluated the performance of the multimodal interface in terms of lap-completion time, the number of commands, and the information transfer rate (ITR) with eight healthy participants. The analysis of the results showed that the eye-tracker with soft-switch provides superior performance with an ITR of 37.77 bits/min among the three different conditions (p<;0.05). Thus, the proposed system provides an effective and economical solution to the Midas-Touch problem and extended usability for the large population of disabled users.

Robust H∞ control of active vehicle suspension under non-stationary running

NASA Astrophysics Data System (ADS)

Guo, Li-Xin; Zhang, Li-Ping

2012-12-01

Due to complexity of the controlled objects, the selection of control strategies and algorithms in vehicle control system designs is an important task. Moreover, the control problem of automobile active suspensions has been become one of the important relevant investigations due to the constrained peculiarity and parameter uncertainty of mathematical models. In this study, after establishing the non-stationary road surface excitation model, a study on the active suspension control for non-stationary running condition was conducted using robust H∞ control and linear matrix inequality optimization. The dynamic equation of a two-degree-of-freedom quarter car model with parameter uncertainty was derived. The H∞ state feedback control strategy with time-domain hard constraints was proposed, and then was used to design the active suspension control system of the quarter car model. Time-domain analysis and parameter robustness analysis were carried out to evaluate the proposed controller stability. Simulation results show that the proposed control strategy has high systemic stability on the condition of non-stationary running and parameter uncertainty (including suspension mass, suspension stiffness and tire stiffness). The proposed control strategy can achieve a promising improvement on ride comfort and satisfy the requirements of dynamic suspension deflection, dynamic tire loads and required control forces within given constraints, as well as non-stationary running condition.

Discrete and continuum links to a nonlinear coupled transport problem of interacting populations

NASA Astrophysics Data System (ADS)

Duong, M. H.; Muntean, A.; Richardson, O. M.

2017-07-01

We are interested in exploring interacting particle systems that can be seen as microscopic models for a particular structure of coupled transport flux arising when different populations are jointly evolving. The scenarios we have in mind are inspired by the dynamics of pedestrian flows in open spaces and are intimately connected to cross-diffusion and thermo-diffusion problems holding a variational structure. The tools we use include a suitable structure of the relative entropy controlling TV-norms, the construction of Lyapunov functionals and particular closed-form solutions to nonlinear transport equations, a hydrodynamics limiting procedure due to Philipowski, as well as the construction of numerical approximates to both the continuum limit problem in 2D and to the original interacting particle systems.

Sexual functioning of people with rheumatoid arthritis: a multicenter study.

PubMed

van Berlo, Willy T M; van de Wiel, Harry B M; Taal, Erik; Rasker, Johannes J; Weijmar Schultz, Willibrord C M; van Rijswijk, Martin H

2007-01-01

The objective of this study is to compare men and women with rheumatoid arthritis (RA) to controls regarding sexual motivation, activity, satisfaction, and specific sexual problems, and to determine the correlation of physical aspects of the disease with sexual functioning. Questionnaire for screening sexual dysfunctions (QSD), self-constructed questionnaire on experienced distress with joints during sexual activities, arthritis impact measurements scales 2 (AIMS2), and the modified disease activity score 28 (DAS 28) were the methods used. RA patients were recruited from a registration base in three Dutch hospitals. Controls were age and sex matched healthy volunteers. A completed questionnaire was sent back by 271 patients (response 23%). Forty-seven men and 93 women were clinically examined to obtain the DAS 28. Male patients felt less sexual desire, and female patients masturbated and fantasized less than controls. Differences in satisfaction were not found. Male and female patients did not experience more sexual problems than controls. Among the women, correlations were predominantly found between age and sexual motivation and activities, among the men between physical health and sexual problems. Up to 41% of the men (4-41 depending on the joints), and up to 51% of the women (10-51 depending on the joints) have troubles with several joints during sexual activities. Medications influencing ejaculation in men correlated with distress with orgasm. Conclusions are that patients are less sexually active than controls and a considerable number of both male and female patients have trouble with their joints during sexual activities. However, patients do not differ from controls regarding sexual satisfaction. Physiological changes due to RA are apparently independent from those on psychological level. It is argued that sexual satisfaction also depends on personal and social factors. In men, physical health and disease activity are more related with sexual problems than in women.

The research of automatic speed control algorithm based on Green CBTC

NASA Astrophysics Data System (ADS)

Lin, Ying; Xiong, Hui; Wang, Xiaoliang; Wu, Youyou; Zhang, Chuanqi

2017-06-01

Automatic speed control algorithm is one of the core technologies of train operation control system. It’s a typical multi-objective optimization control algorithm, which achieve the train speed control for timing, comfort, energy-saving and precise parking. At present, the train speed automatic control technology is widely used in metro and inter-city railways. It has been found that the automatic speed control technology can effectively reduce the driver’s intensity, and improve the operation quality. However, the current used algorithm is poor at energy-saving, even not as good as manual driving. In order to solve the problem of energy-saving, this paper proposes an automatic speed control algorithm based on Green CBTC system. Based on the Green CBTC system, the algorithm can adjust the operation status of the train to improve the efficient using rate of regenerative braking feedback energy while ensuring the timing, comfort and precise parking targets. Due to the reason, the energy-using of Green CBTC system is lower than traditional CBTC system. The simulation results show that the algorithm based on Green CBTC system can effectively reduce the energy-using due to the improvement of the using rate of regenerative braking feedback energy.

Microgravity vibration isolation: Optimal preview and feedback control

NASA Technical Reports Server (NTRS)

Hampton, R. D.; Knospe, C. R.; Grodsinsky, C. M.; Allaire, P. E.; Lewis, D. W.

1992-01-01

In order to achieve adequate low-frequency vibration isolation for certain space experiments an active control is needed, due to inherent passive-isolator limitations. Proposed here are five possible state-space models for a one-dimensional vibration isolation system with a quadratic performance index. The five models are subsets of a general set of nonhomogeneous state space equations which includes disturbance terms. An optimal control is determined, using a differential equations approach, for this class of problems. This control is expressed in terms of constant, Linear Quadratic Regulator (LQR) feedback gains and constant feedforward (preview) gains. The gains can be easily determined numerically. They result in a robust controller and offers substantial improvements over a control that uses standard LQR feedback alone.

Prosthodontic management of segmental mandibulectomy patient with guidance appliance and overlay denture.

PubMed

Aruna, U; Thulasingam, C

2013-12-01

Patients who undergo segmental or hemi-mandibulectomy suffer from various postoperative problems in esthetics and function. The solution to such problem is providing a mandibular guidance appliance to correct mandibular deviation to resected side due to loss of muscle action on the affected side. This article describes the treatment of a female patient who underwent segmental mandibulectomy on right side secondary to adenoid cystic carcinoma of the base of tongue. An acrylic guidance appliance was constructed to help control the mandibular deviation and co-ordinate masticatory movements. The prosthesis was worn continuously by the patient for 1 month which corrected the occlusion on the left side. To compensate for the open-bite caused due to rotation of mandible following partial mandibulectomy, an overlay removable partial denture was given. The patient was satisfied with the improvement in esthetics and mastication.

Silicon solar cell process development, fabrication, and analysis

NASA Technical Reports Server (NTRS)

Yoo, H. I.; Iles, P. A.; Leung, D. C.

1981-01-01

Work has progressed in fabrication and characterization of solar cells from ubiquitous crystallization process (UCP) wafers and LASS ribbons. Gettering tests applied to UCP wafers made little change on their performance compared with corresponding baseline data. Advanced processes such as shallow junction (SJ), back surface field (BSF), and multilayer antireflection (MLAR) were also applied. While BSF by Al paste had shunting problems, cells with SJ and BSF by evaporated Al, and MLAR did achieve 14.1% AMI on UCP silicon. The study of LASS material was very preliminary. Only a few cells with SJ, BSR, (no BSF) and MLAR were completed due to mechanical yield problems after lapping the material. Average efficiency was 10.7% AMI with 13.4% AMI for CZ controls. Relatively high minority carrier diffusion lengths were obtained. The lower than expected Jsc could be partially explained by low active area due to irregular sizes.

Production loss among employees perceiving work environment problems.

PubMed

Lohela-Karlsson, Malin; Hagberg, Jan; Bergström, Gunnar

2015-08-01

The overall aim of this explorative study was to investigate the relationship between factors in the psychosocial work environment and work environment-related production loss. Employees at a Swedish university were invited to answer a workplace questionnaire and were selected for this study if they reported having experienced work environment-related problems in the past 7 days (n = 302). A stepwise logistic regression and a modified Poisson regression were used to identify psychosocial work factors associated with work environment-related production loss as well as to identify at what level those factors are associated with production loss. Employees who reported having experienced work environment problems but also fair leadership, good social climate, role clarity and control of decision had significantly lower levels of production loss, whereas employees who reported inequality and high decision demands reported significantly higher levels of production loss. Never or seldom experiencing fair leadership, role clarity, equality, decision demands and good social climate increase the risk of production loss due to work environment problems, compared to those who experience these circumstances frequently, always or most of the time. Several psychosocial work factors are identified as factors associated with a reduced risk of production losses among employees despite the nature of the work environment problem. Knowledge of these factors may be important not only to reduce employee ill-health and the corresponding health-related production loss, but also reduce immediate production loss due to work environment-related problems.

Neural self-tuning adaptive control of non-minimum phase system

NASA Technical Reports Server (NTRS)

Ho, Long T.; Bialasiewicz, Jan T.; Ho, Hai T.

1993-01-01

The motivation of this research came about when a neural network direct adaptive control scheme was applied to control the tip position of a flexible robotic arm. Satisfactory control performance was not attainable due to the inherent non-minimum phase characteristics of the flexible robotic arm tip. Most of the existing neural network control algorithms are based on the direct method and exhibit very high sensitivity, if not unstable, closed-loop behavior. Therefore, a neural self-tuning control (NSTC) algorithm is developed and applied to this problem and showed promising results. Simulation results of the NSTC scheme and the conventional self-tuning (STR) control scheme are used to examine performance factors such as control tracking mean square error, estimation mean square error, transient response, and steady state response.

Microgravity Vibration Control and Civil Applications

NASA Technical Reports Server (NTRS)

Whorton, Mark Stephen; Alhorn, Dean Carl

1998-01-01

Controlling vibration of structures is essential for both space structures as well as terrestrial structures. Due to the ambient acceleration levels anticipated for the International Space Station, active vibration isolation is required to provide a quiescent acceleration environment for many science experiments. An overview is given of systems developed and flight tested in orbit for microgravity vibration isolation. Technology developed for vibration control of flexible space structures may also be applied to control of terrestrial structures such as buildings and bridges subject to wind loading or earthquake excitation. Recent developments in modern robust control for flexible space structures are shown to provide good structural vibration control while maintaining robustness to model uncertainties. Results of a mixed H-2/H-infinity control design are provided for a benchmark problem in structural control for earthquake resistant buildings.

Mother and Child Behaviour in Very Preterm and Term Dyads at 6 and 8 Years

ERIC Educational Resources Information Center

Jaekel, Julia; Wolke, Dieter; Chernova, Julia

2012-01-01

Aim: Mothers of very preterm children have been reported to behave less sensitively and to be more controlling. It is unknown whether this is the result of maternal factors or due to maternal adaptation to children's cognitive problems. Method: We investigated a geographically defined prospective whole-population sample of very low birthweight (…

HACCP-based quality risk management approach to udder health problems on dairy farms

PubMed Central

2009-01-01

Against the background of prevailing udder health problems on dairy farms, this paper discusses a new approach to mastitis control. Current udder health control programmes, such as the 'five-point plan', are highlighted and their drawbacks indicated. The concept and principles of hazard analysis critical control points (HACCP) are introduced. The eight core elements of this concept are dealt with by using the example of a dairy herd with a mastitis problem due to Staphylococcus aureus. The various steps to be taken in the development of a HACCP-based quality risk management programme are illustrated through the application of core elements. Finally, it is shown that the HACCP key words, structure, organisation, planning, communication and formalisation; which do not frequently appear in conventional herd health and production management programmes can contribute to better udder health. The role of the veterinarian can be paramount and of added value, if he/she is willing to invest in new knowledge and skills, such as the HACCP concept, farm economics, animal nutrition, and particularly the role of coach to the dairy farmer in the implementation of preventative measures in relation to udder health. PMID:22082372

HACCP-based quality risk management approach to udder health problems on dairy farms.

PubMed

Noordhuizen, Jptm; Cannas da Silva, J

2009-04-01

Against the background of prevailing udder health problems on dairy farms, this paper discusses a new approach to mastitis control. Current udder health control programmes, such as the 'five-point plan', are highlighted and their drawbacks indicated. The concept and principles of hazard analysis critical control points (HACCP) are introduced. The eight core elements of this concept are dealt with by using the example of a dairy herd with a mastitis problem due to Staphylococcus aureus. The various steps to be taken in the development of a HACCP-based quality risk management programme are illustrated through the application of core elements. Finally, it is shown that the HACCP key words, structure, organisation, planning, communication and formalisation; which do not frequently appear in conventional herd health and production management programmes can contribute to better udder health. The role of the veterinarian can be paramount and of added value, if he/she is willing to invest in new knowledge and skills, such as the HACCP concept, farm economics, animal nutrition, and particularly the role of coach to the dairy farmer in the implementation of preventative measures in relation to udder health.

Integrated control of Chagas disease for its elimination as public health problem - A Review

PubMed Central

Sosa-Estani, Sergio; Segura, Elsa Leonor

2015-01-01

Chagas disease or American trypanosomiasis is, together with geohelminths, the neglected disease that causes more loss of years of healthy life due to disability in Latin America. Chagas disease, as determined by the factors and determinants, shows that different contexts require different actions, preventing new cases or reducing the burden of disease. Control strategies must combine two general courses of action including prevention of transmission to prevent the occurrence of new cases (these measures are cost effective), as well as opportune diagnosis and treatment of infected individuals in order to prevent the clinical evolution of the disease and to allow them to recuperate their health. All actions should be implemented as fully as possible and with an integrated way, to maximise the impact. Chagas disease cannot be eradicated due because of the demonstrated existence of infected wild triatomines in permanent contact with domestic cycles and it contributes to the occurrence of at least few new cases. However, it is possible to interrupt the transmission of Trypanosoma cruzi in a large territory and to eliminate Chagas disease as a public health problem with a dramatic reduction of burden of the disease. PMID:25993503

The artificial object detection and current velocity measurement using SAR ocean surface images

NASA Astrophysics Data System (ADS)

Alpatov, Boris; Strotov, Valery; Ershov, Maksim; Muraviev, Vadim; Feldman, Alexander; Smirnov, Sergey

2017-10-01

Due to the fact that water surface covers wide areas, remote sensing is the most appropriate way of getting information about ocean environment for vessel tracking, security purposes, ecological studies and others. Processing of synthetic aperture radar (SAR) images is extensively used for control and monitoring of the ocean surface. Image data can be acquired from Earth observation satellites, such as TerraSAR-X, ERS, and COSMO-SkyMed. Thus, SAR image processing can be used to solve many problems arising in this field of research. This paper discusses some of them including ship detection, oil pollution control and ocean currents mapping. Due to complexity of the problem several specialized algorithm are necessary to develop. The oil spill detection algorithm consists of the following main steps: image preprocessing, detection of dark areas, parameter extraction and classification. The ship detection algorithm consists of the following main steps: prescreening, land masking, image segmentation combined with parameter measurement, ship orientation estimation and object discrimination. The proposed approach to ocean currents mapping is based on Doppler's law. The results of computer modeling on real SAR images are presented. Based on these results it is concluded that the proposed approaches can be used in maritime applications.

Integrated control of Chagas disease for its elimination as public health problem--a review.

PubMed

Sosa-Estani, Sergio; Segura, Elsa Leonor

2015-05-01

Chagas disease or American trypanosomiasis is, together with geohelminths, the neglected disease that causes more loss of years of healthy life due to disability in Latin America. Chagas disease, as determined by the factors and determinants, shows that different contexts require different actions, preventing new cases or reducing the burden of disease. Control strategies must combine two general courses of action including prevention of transmission to prevent the occurrence of new cases (these measures are cost effective), as well as opportune diagnosis and treatment of infected individuals in order to prevent the clinical evolution of the disease and to allow them to recuperate their health. All actions should be implemented as fully as possible and with an integrated way, to maximise the impact. Chagas disease cannot be eradicated due because of the demonstrated existence of infected wild triatomines in permanent contact with domestic cycles and it contributes to the occurrence of at least few new cases. However, it is possible to interrupt the transmission of Trypanosoma cruzi in a large territory and to eliminate Chagas disease as a public health problem with a dramatic reduction of burden of the disease.

Self-help cognitive behavior therapy for working women with problematic hot flushes and night sweats (MENOS@Work): a multicenter randomized controlled trial.

PubMed

Hardy, Claire; Griffiths, Amanda; Norton, Sam; Hunter, Myra S

2018-05-01

The aim of the study was to examine the efficacy of an unguided, self-help cognitive behavior therapy (SH-CBT) booklet on hot flush and night sweat (HFNS) problem rating, delivered in a work setting. Women aged 45 to 60 years, having 10 or more problematic HFNS a week, were recruited to a multicenter randomized controlled trial, via the occupational health/human resources departments of eight organizations. Participants were 1:1 randomized to SH-CBT or no treatment waitlist control (NTWC). The primary outcome was HFNS problem rating; secondary outcomes included HFNS frequency, work and social adjustment, sleep, mood, beliefs and behaviors, and work-related variables (absence, performance, turnover intention, and work impairment due to presenteeism). Intention-to-treat analysis was used, and between-group differences estimated using linear mixed models. A total of 124 women were randomly allocated to SH-CBT (n = 60) and NTWC (n = 64). 104 (84%) were assessed for primary outcome at 6 weeks and 102 (82%) at 20 weeks. SH-CBT significantly reduced HFNS problem rating at 6 weeks (SH-CBT vs NTWC adjusted mean difference, -1.49; 95% CI, -2.11 to -0.86; P < 0.001) and at 20 weeks (-1.09; 95% CI, -1.87 to -0.31; P < 0.01). SH-CBT also significantly reduced HFNS frequency, improved work and social adjustment; sleep, menopause beliefs, HFNS beliefs/behaviors at 6 and 20 weeks; improved wellbeing and somatic symptoms and reduced work impairment due to menopause-related presenteeism at 20 weeks, compared with the NTWC. There was no difference between groups in other work-related outcomes. A brief, unguided SH-CBT booklet is a potentially effective management option for working women experiencing problematic HFNS.

Biological control of invasive plant species: a reassessment for the Anthropocene.

PubMed

Seastedt, Timothy R

2015-01-01

The science of finding, testing and releasing herbivores and pathogens to control invasive plant species has achieved a level of maturity and success that argues for continued and expanded use of this program. The practice, however, remains unpopular with some conservationists, invasion biologists, and stakeholders. The ecological and economic benefits of controlling densities of problematic plant species using biological control agents can be quantified, but the risks and net benefits of biological control programs are often derived from social or cultural rather than scientific criteria. Management of invasive plants is a 'wicked problem', and local outcomes to wicked problems have both positive and negative consequences differentially affecting various groups of stakeholders. The program has inherent uncertainties; inserting species into communities that are experiencing directional or even transformational changes can produce multiple outcomes due to context-specific factors that are further confounded by environmental change drivers. Despite these uncertainties, biological control could play a larger role in mitigation and adaptation strategies used to maintain biological diversity as well as contribute to human well-being by protecting food and fiber resources. © 2014 The Author New Phytologist © 2014 New Phytologist Trust.

Single-machine common/slack due window assignment problems with linear decreasing processing times

NASA Astrophysics Data System (ADS)

Zhang, Xingong; Lin, Win-Chin; Wu, Wen-Hsiang; Wu, Chin-Chia

2017-08-01

This paper studies linear non-increasing processing times and the common/slack due window assignment problems on a single machine, where the actual processing time of a job is a linear non-increasing function of its starting time. The aim is to minimize the sum of the earliness cost, tardiness cost, due window location and due window size. Some optimality results are discussed for the common/slack due window assignment problems and two O(n log n) time algorithms are presented to solve the two problems. Finally, two examples are provided to illustrate the correctness of the corresponding algorithms.

Living with faecal incontinence: trying to control the daily life that is out of control.

PubMed

Olsson, Frida; Berterö, Carina

2015-01-01

To identify and describe the lived experience of persons living with faecal incontinence and show how it affects daily life. Faecal incontinence is a relatively common condition, with a prevalence ranging from 3-24%, not differing between men and women. There is an under-reporting due to patients' reluctance to talk about their symptoms and consult healthcare professionals about their problems, which means that problems related to faecal incontinence are often underestimated. Living with faecal incontinence affects the quality of life negatively and has a negative impact on family situations, social interaction, etc. A qualitative interpretative study based on interviews. In-depth interviews were conducted with five informants, all women, living with faecal incontinence. The interviews were transcribed verbatim and analysed using interpretive phenomenological analysis. The analysis identified four themes: self-affirmation, guilt and shame, limitations in life and personal approach. The themes differ from each other, but are related and have similarities. The results show different aspects of living with faecal incontinence and how they affected daily life. Living with faecal incontinence is a complex problem affecting everyday life in a number of different ways. It is a highly distressing and socially incapacitating problem. Living with faecal incontinence is about trying to control the daily life which is out of control. Living with faecal incontinence cannot be generalised as individuals experience the situation in unique ways. By gaining insight into the experience of living with faecal incontinence, healthcare professionals can deepen their understanding of this complex problem and thereby better address it and provide more individually based care. © 2014 John Wiley & Sons Ltd.

Almost output regulation of LFT systems via gain-scheduling control

NASA Astrophysics Data System (ADS)

Yuan, Chengzhi; Duan, Chang; Wu, Fen

2018-05-01

Output regulation of general uncertain systems is a meaningful yet challenging problem. In spite of the rich literature in the field, the problem has not yet been addressed adequately due to the lack of an effective design mechanism. In this paper, we propose a new design framework for almost output regulation of uncertain systems described in the general form of linear fractional transformation (LFT) with time-varying parametric uncertainties and unknown external perturbations. A novel semi-LFT gain-scheduling output regulator structure is proposed, such that the associated control synthesis conditions guaranteeing both output regulation and ? disturbance attenuation performance are formulated as a set of linear matrix inequalities (LMIs) plus parameter-dependent linear matrix equations, which can be solved separately. A numerical example has been used to demonstrate the effectiveness of the proposed approach.

Robust Flight Path Determination for Mars Precision Landing Using Genetic Algorithms

NASA Technical Reports Server (NTRS)

Bayard, David S.; Kohen, Hamid

1997-01-01

This paper documents the application of genetic algorithms (GAs) to the problem of robust flight path determination for Mars precision landing. The robust flight path problem is defined here as the determination of the flight path which delivers a low-lift open-loop controlled vehicle to its desired final landing location while minimizing the effect of perturbations due to uncertainty in the atmospheric model and entry conditions. The genetic algorithm was capable of finding solutions which reduced the landing error from 111 km RMS radial (open-loop optimal) to 43 km RMS radial (optimized with respect to perturbations) using 200 hours of computation on an Ultra-SPARC workstation. Further reduction in the landing error is possible by going to closed-loop control which can utilize the GA optimized paths as nominal trajectories for linearization.

[The problem of small "n" and big "P" in neuropsycho-pharmacology, or how to keep the rate of false discoveries under control].

PubMed

Petschner, Péter; Bagdy, György; Tóthfalusi, Laszló

2015-03-01

One of the characteristics of many methods used in neuropsychopharmacology is that a large number of parameters (P) are measured in relatively few subjects (n). Functional magnetic resonance imaging, electroencephalography (EEG) and genomic studies are typical examples. For example one microarray chip can contain thousands of probes. Therefore, in studies using microarray chips, P may be several thousand-fold larger than n. Statistical analysis of such studies is a challenging task and they are refereed to in the statistical literature such as the small "n" big "P" problem. The problem has many facets including the controversies associated with multiple hypothesis testing. A typical scenario in this context is, when two or more groups are compared by the individual attributes. If the increased classification error due to the multiple testing is neglected, then several highly significant differences will be discovered. But in reality, some of these significant differences are coincidental, not reproducible findings. Several methods were proposed to solve this problem. In this review we discuss two of the proposed solutions, algorithms to compare sets and statistical hypothesis tests controlling the false discovery rate.

Community Violence Exposure and Conduct Problems in Children and Adolescents with Conduct Disorder and Healthy Controls

PubMed Central

Kersten, Linda; Vriends, Noortje; Steppan, Martin; Raschle, Nora M.; Praetzlich, Martin; Oldenhof, Helena; Vermeiren, Robert; Jansen, Lucres; Ackermann, Katharina; Bernhard, Anka; Martinelli, Anne; Gonzalez-Madruga, Karen; Puzzo, Ignazio; Wells, Amy; Rogers, Jack C.; Clanton, Roberta; Baker, Rosalind H.; Grisley, Liam; Baumann, Sarah; Gundlach, Malou; Kohls, Gregor; Gonzalez-Torres, Miguel A.; Sesma-Pardo, Eva; Dochnal, Roberta; Lazaratou, Helen; Kalogerakis, Zacharias; Bigorra Gualba, Aitana; Smaragdi, Areti; Siklósi, Réka; Dikeos, Dimitris; Hervás, Amaia; Fernández-Rivas, Aranzazu; De Brito, Stephane A.; Konrad, Kerstin; Herpertz-Dahlmann, Beate; Fairchild, Graeme; Freitag, Christine M.; Popma, Arne; Kieser, Meinhard; Stadler, Christina

2017-01-01

Exposure to community violence through witnessing or being directly victimized has been associated with conduct problems in a range of studies. However, the relationship between community violence exposure (CVE) and conduct problems has never been studied separately in healthy individuals and individuals with conduct disorder (CD). Therefore, it is not clear whether the association between CVE and conduct problems is due to confounding factors, because those with high conduct problems also tend to live in more violent neighborhoods, i.e., an ecological fallacy. Hence, the aim of the present study was: (1) to investigate whether the association between recent CVE and current conduct problems holds true for healthy controls as well as adolescents with a diagnosis of CD; (2) to examine whether the association is stable in both groups when including effects of aggression subtypes (proactive/reactive aggression), age, gender, site and socioeconomic status (SES); and (3) to test whether proactive or reactive aggression mediate the link between CVE and conduct problems. Data from 1178 children and adolescents (62% female; 44% CD) aged between 9 years and 18 years from seven European countries were analyzed. Conduct problems were assessed using the Kiddie-Schedule of Affective Disorders and Schizophrenia diagnostic interview. Information about CVE and aggression subtypes was obtained using self-report questionnaires (Social and Health Assessment and Reactive-Proactive aggression Questionnaire (RPQ), respectively). The association between witnessing community violence and conduct problems was significant in both groups (adolescents with CD and healthy controls). The association was also stable after examining the mediating effects of aggression subtypes while including moderating effects of age, gender and SES and controlling for effects of site in both groups. There were no clear differences between the groups in the strength of the association between witnessing violence and conduct problems. However, we found evidence for a ceiling effect, i.e., individuals with very high levels of conduct problems could not show a further increase if exposed to CVE and vice versa. Results indicate that there was no evidence for an ecological fallacy being the primary cause of the association, i.e., CVE must be considered a valid risk factor in the etiology of CD. PMID:29163090

Cognitive process modelling of controllers in en route air traffic control.

PubMed

Inoue, Satoru; Furuta, Kazuo; Nakata, Keiichi; Kanno, Taro; Aoyama, Hisae; Brown, Mark

2012-01-01

In recent years, various efforts have been made in air traffic control (ATC) to maintain traffic safety and efficiency in the face of increasing air traffic demands. ATC is a complex process that depends to a large degree on human capabilities, and so understanding how controllers carry out their tasks is an important issue in the design and development of ATC systems. In particular, the human factor is considered to be a serious problem in ATC safety and has been identified as a causal factor in both major and minor incidents. There is, therefore, a need to analyse the mechanisms by which errors occur due to complex factors and to develop systems that can deal with these errors. From the cognitive process perspective, it is essential that system developers have an understanding of the more complex working processes that involve the cooperative work of multiple controllers. Distributed cognition is a methodological framework for analysing cognitive processes that span multiple actors mediated by technology. In this research, we attempt to analyse and model interactions that take place in en route ATC systems based on distributed cognition. We examine the functional problems in an ATC system from a human factors perspective, and conclude by identifying certain measures by which to address these problems. This research focuses on the analysis of air traffic controllers' tasks for en route ATC and modelling controllers' cognitive processes. This research focuses on an experimental study to gain a better understanding of controllers' cognitive processes in air traffic control. We conducted ethnographic observations and then analysed the data to develop a model of controllers' cognitive process. This analysis revealed that strategic routines are applicable to decision making.

Occupational health and safety in the least developed countries--a simple case of neglect.

PubMed

Ahasan, M R; Partanen, T

2001-03-01

In many of the least developed countries, working people are significantly exposed to a number of occupational problems that may result in a deterioration of their health, safety and well being. These work-related problems are untenable, not only because of the occupational problems itself but also because of the simultaneous exposure to heat, dusts, noise, organo-chemicals, and biological and environmental pollution. This situation has existed for a long time due to various socio economic,geographical, cultural and local factors. The deteriorating situation of health and safety in the workplace may perhaps exist due to the inadequate resource facilities, economic constraints and lack of opportunity to conduct research and studies on the assessment of exposure-diseases associations. Officials, who are employed by the state, are not able to implement work regulations and labour legislation easily. Generally, they are not professionally trained and expert in the occupational health, industrial hygiene and/or safety fields, and thus, successful application and implementation of control measures are lacking. Steps to control work exposure limits have been ineffective, since national policies have been rare, owing to the multiple obstacles in preventing occupational problems. However, the major focus is on practical solutions to differing workers' needs, consideration of which is very important, depending on the what the industrial entrepreneurs could reasonably to be expected to afford. Why there is a lack of motivation and effort regarding the development of health and safety-this paper explores some important issues, aiming to focus public attention on the legacy of national and international efforts. Examples are likewise given to show the real situation of health and safety in the least developed countries.

Boundary control of bidomain equations with state-dependent switching source functions in the ionic model

NASA Astrophysics Data System (ADS)

Chamakuri, Nagaiah; Engwer, Christian; Kunisch, Karl

2014-09-01

Optimal control for cardiac electrophysiology based on the bidomain equations in conjunction with the Fenton-Karma ionic model is considered. This generic ventricular model approximates well the restitution properties and spiral wave behavior of more complex ionic models of cardiac action potentials. However, it is challenging due to the appearance of state-dependent discontinuities in the source terms. A computational framework for the numerical realization of optimal control problems is presented. Essential ingredients are a shape calculus based treatment of the sensitivities of the discontinuous source terms and a marching cubes algorithm to track iso-surface of excitation wavefronts. Numerical results exhibit successful defibrillation by applying an optimally controlled extracellular stimulus.

Steady-state bumpless transfer under controller uncertainty using the state/output feedback topology

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

Zheng, K.; Lee, A.H.; Bentsman, J.

2006-01-15

Linear quadratic (LQ) bumpless transfer design introduced recently by Turner and Walker gives a very convenient and straightforward computational procedure for the steady-state bumpless transfer operator synthesis. It is, however, found to be incapable of providing convergence of the output of the offline controller to that of the online controller in several industrial applications, producing bumps in the plant output in the wake of controller transfer. An examination of this phenomenon reveals that the applications in question are characterized by a significant mismatch, further referred to as controller uncertainty, between the dynamics of the implemented controllers and their models usedmore » in the transfer operator computation. To address this problem, while retaining the convenience of the Turner and Walker design, a novel state/output feedback bumpless transfer topology is introduced that employs the nominal state of the offline controller and, through the use of an additional controller/model mismatch compensator, also the offline controller output. A corresponding steady-state bumpless transfer design procedure along with the supporting theory is developed for a large class of systems. Due to these features, it is demonstrated to solve a long-standing problem of high-quality steady-state bumpless transfer from the industry standard low-order nonlinear multiloop PID-based controllers to the modern multiinput-multioutput (MIMO) robust controllers in the megawatt/throttle pressure control of a typical coal-fired boiler/turbine unit.« less

Performance analysis and simulation of the SPS reference phase control system

NASA Technical Reports Server (NTRS)

Lindsey, W. C.; Chie, C. M.

1980-01-01

The major elements required in the operation of an SPS which employs retrodirectivity as a means of pointing the beam to Earth include the spacetenna, the rectenna, and the pilot signal transmitter. The phase control system is faced with several problems: (1) path delay variations due to imperfect SPS circular orbits; (2) ionospheric effects; (3) initial phase beam forming; (4) beam pointing; (5) beam safing; (6) high power phase noise effects; and (7) interference. The use of SOLARISM, a computer program to select pilot signal parameters and evaluate SPS performance is described.

A voice coil actuator driven active vibration isolation system with the consideration of flexible modes.

PubMed

Park, Kyihwan; Choi, Dongyoub; Ozer, Abdullah; Kim, Sangyoo; Lee, Yongkwan; Joo, Dongik

2008-06-01

We develop a four-mount active vibration isolation system (AVIS) using voice coil actuators. The flexible body modes in the upper plate of the AVIS can cause an instability problem due to control signal whose frequency is close to the resonant frequency of the flexible modes. The loop shaping technique is applied to reduce the amplitude of the control signal. We investigate the performances of the active vibration isolation system proposed in the word in the time domain and frequency domain by comparing to the passive isolation system.

Identity management and privacy languages technologies: Improving user control of data privacy

NASA Astrophysics Data System (ADS)

García, José Enrique López; García, Carlos Alberto Gil; Pacheco, Álvaro Armenteros; Organero, Pedro Luis Muñoz

The identity management solutions have the capability to bring confidence to internet services, but this confidence could be improved if user has more control over the privacy policy of its attributes. Privacy languages could help to this task due to its capability to define privacy policies for data in a very flexible way. So, an integration problem arises: making work together both identity management and privacy languages. Despite several proposals for accomplishing this have already been defined, this paper suggests some topics and improvements that could be considered.

Autonomous Control Modes and Optimized Path Guidance for Shipboard Landing in High Sea States

DTIC Science & Technology

2017-01-09

due to the inherent nose up attitude of the helicopter. Once the tail gear makes contact (almost always with low relative velocity), the control...n V Z ( ft /s ) Front Gear 2 -10 -8 -6 -4 -2 0 2 4 6 8 10 0 2 4 6 8 10 Touchdown V Y (ft/s) Tail Gear This problem is a consequence of attitude ...mismatch at touchdown; where the aircraft attitude does not comply with the deck orientation. Attitude mismatch is a common for helicopter; even a land

A Sarsa(λ)-based control model for real-time traffic light coordination.

PubMed

Zhou, Xiaoke; Zhu, Fei; Liu, Quan; Fu, Yuchen; Huang, Wei

2014-01-01

Traffic problems often occur due to the traffic demands by the outnumbered vehicles on road. Maximizing traffic flow and minimizing the average waiting time are the goals of intelligent traffic control. Each junction wants to get larger traffic flow. During the course, junctions form a policy of coordination as well as constraints for adjacent junctions to maximize their own interests. A good traffic signal timing policy is helpful to solve the problem. However, as there are so many factors that can affect the traffic control model, it is difficult to find the optimal solution. The disability of traffic light controllers to learn from past experiences caused them to be unable to adaptively fit dynamic changes of traffic flow. Considering dynamic characteristics of the actual traffic environment, reinforcement learning algorithm based traffic control approach can be applied to get optimal scheduling policy. The proposed Sarsa(λ)-based real-time traffic control optimization model can maintain the traffic signal timing policy more effectively. The Sarsa(λ)-based model gains traffic cost of the vehicle, which considers delay time, the number of waiting vehicles, and the integrated saturation from its experiences to learn and determine the optimal actions. The experiment results show an inspiring improvement in traffic control, indicating the proposed model is capable of facilitating real-time dynamic traffic control.

Optimal speech motor control and token-to-token variability: a Bayesian modeling approach.

PubMed

Patri, Jean-François; Diard, Julien; Perrier, Pascal

2015-12-01

The remarkable capacity of the speech motor system to adapt to various speech conditions is due to an excess of degrees of freedom, which enables producing similar acoustical properties with different sets of control strategies. To explain how the central nervous system selects one of the possible strategies, a common approach, in line with optimal motor control theories, is to model speech motor planning as the solution of an optimality problem based on cost functions. Despite the success of this approach, one of its drawbacks is the intrinsic contradiction between the concept of optimality and the observed experimental intra-speaker token-to-token variability. The present paper proposes an alternative approach by formulating feedforward optimal control in a probabilistic Bayesian modeling framework. This is illustrated by controlling a biomechanical model of the vocal tract for speech production and by comparing it with an existing optimal control model (GEPPETO). The essential elements of this optimal control model are presented first. From them the Bayesian model is constructed in a progressive way. Performance of the Bayesian model is evaluated based on computer simulations and compared to the optimal control model. This approach is shown to be appropriate for solving the speech planning problem while accounting for variability in a principled way.

Commercialization of the power factor controller

NASA Technical Reports Server (NTRS)

1981-01-01

The purpose of the Motor Power Controller, also known as the Power Factor Controller, is to improve power factor and reduce power dissipation in induction motors operating below full load. These purposes were studied and tested in detail. The Motor Power Controller is capable of raising power factors from 0.2 to 0.8 and results in energy savings. It was found that many motors, in their present operating applications, are classified as unstable. The electronic nature of the controller vs. the electrical nature of the motor, compound this problem due to the differences in response time of the two devices. Many tests were successfully completed, the most indicating greater savings than anticipated. Also, there was an effect on efficiency which was not included in the calculations.

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.

Collaborative Access Control For Critical Infrastructures

NASA Astrophysics Data System (ADS)

Baina, Amine; El Kalam, Anas Abou; Deswarte, Yves; Kaaniche, Mohamed

A critical infrastructure (CI) can fail with various degrees of severity due to physical and logical vulnerabilities. Since many interdependencies exist between CIs, failures can have dramatic consequences on the entire infrastructure. This paper focuses on threats that affect information and communication systems that constitute the critical information infrastructure (CII). A new collaborative access control framework called PolyOrBAC is proposed to address security problems that are specific to CIIs. The framework offers each organization participating in a CII the ability to collaborate with other organizations while maintaining control of its resources and internal security policy. The approach is demonstrated on a practical scenario involving the electrical power grid.

Pointing control for LDR

NASA Technical Reports Server (NTRS)

Yam, Y.; Briggs, C.

1988-01-01

One important aspect of the LDR control problem is the possible excitations of structural modes due to random disturbances, mirror chopping, and slewing maneuvers. An analysis was performed to yield a first order estimate of the effects of such dynamic excitations. The analysis involved a study of slewing jitters, chopping jitters, disturbance responses, and pointing errors, making use of a simplified planar LDR model which describes the LDR dynamics on a plane perpendicular to the primary reflector. Briefly, the results indicate that the command slewing profile plays an important role in minimizing the resultant jitter, even to a level acceptable without any control action. An optimal profile should therefore be studied.

Multidrug-resistant tuberculosis: The problem and some priorities in controlling it.

PubMed

Hoffner, Sven

2016-12-01

Multidrug-resistant tuberculosis (MDR-TB), and even more severe forms of drug resistance, cause significant problems and costs for national TB control programs and constitutes an increasing public health concern globally. In parts of the former Soviet Union, the prevalence of MDR-TB is as high as 50% and one third of all newly detected TB patients are infected with MDR strains. Such strains transmit and certain MDR-TB clones constitute an important part of the problem, especially in high MDR-TB burden areas. There are several actions that should be given priority to control this situation. A first important step is timely detection of all patients infected with resistant strains, which makes possible prompt change of standard TB chemotherapy to more effective combinations of drugs. This is important both from the public health and clinical perspectives, since it renders the individual patient noninfectious and subsequently cured. Early detection of MDR-TB also allows infection control to be focused where it is most needed. Strengthened infection control measures are crucial for limiting the ongoing spread of resistant TB in hospitals and elsewhere. In addition, a sustainable drug supply must be ensured to guarantee that all patients are initiated on effective treatment and can avoid interruptions due to drug shortages. An extra focus should be put on vulnerable cases, such as immunosuppressed individuals, prisoners, drug addicts, and migrants, in whom TB is generally more frequent and difficult to control than in the normal population. Finally, political support is needed to ensure necessary infrastructures, human and financial resources to effectively control drug resistant TB. Copyright © 2016.

Autonomous spacecraft attitude control using magnetic torquing only

NASA Technical Reports Server (NTRS)

Musser, Keith L.; Ebert, Ward L.

1989-01-01

Magnetic torquing of spacecraft has been an important mechanism for attitude control since the earliest satellites were launched. Typically a magnetic control system has been used for precession/nutation damping for gravity-gradient stabilized satellites, momentum dumping for systems equipped with reaction wheels, or momentum-axis pointing for spinning and momentum-biased spacecraft. Although within the small satellite community there has always been interest in expensive, light-weight, and low-power attitude control systems, completely magnetic control systems have not been used for autonomous three-axis stabilized spacecraft due to the large computational requirements involved. As increasingly more powerful microprocessors have become available, this has become less of an impediment. These facts have motivated consideration of the all-magnetic attitude control system presented here. The problem of controlling spacecraft attitude using only magnetic torquing is cast into the form of the Linear Quadratic Regulator (LQR), resulting in a linear feedback control law. Since the geomagnetic field along a satellite trajectory is not constant, the system equations are time varying. As a result, the optimal feedback gains are time-varying. Orbit geometry is exploited to treat feedback gains as a function of position rather than time, making feasible the onboard solution of the optimal control problem. In simulations performed to date, the control laws have shown themselves to be fairly robust and a good candidate for an onboard attitude control system.

Affective personality as cognitive-emotional presymptom profiles regulatory for self-reported health predispositions.

PubMed

Archer, T; Adolfsson, B; Karlsson, E

2008-08-01

Three studies that examined the links between affective personality, as constructed from responses to the Positive Affect (PA) and Negative Affect (NA) Scale (PANAS), and individuals' self-report of self-esteem, intrinsic motivation and Beck's Depression Inventory (BDI) depression in high school students and persons in working occupations are described. Self-report estimations of several other neuropsychiatric and psychosocial variables including, the Uppsala Sleep Inventory (USI), the Hospital Anxiety and Depression (HAD) test, Dispositional optimism, Locus of control, the Subjective Stress Experience test (SSE) and the Stress-Energy (SE) test, were also derived. Marked effects due to affective personality type upon somatic and psychological stress, anxiety and depression, self-esteem, internal and external locus of control, optimism, stress and energy, intrinsic motivation, external regulation, identified regulation, major sleep problems, problems falling asleep, and psychophysiological problems were observed; levels of self-esteem, self-motivation and BDI-depression all produced substantial effects on health and well-being. Regression analyses indicated PA was predicted by dispositional optimism (thrice), energy (thrice), and intrinsic motivation, and counter predicted by depression (twice) and stress (twice); and NA by anxiety (twice), stress (twice), psychological stress, identified regulation, BDI depression and psychophysiological problems, and counter predicted by internal locus of control and self-esteem. BDI-depression was predicted by negative affect, major sleep problems and psychophysiological problems (Study III), self-esteem by dispositional optimism and energy, and counter predicted by anxiety, depression and stress (Study I), and intrinsic motivation by dispositional optimism, energy, PA and self-esteem (Study II). These convergent findings are interpreted from a perspective of the cognitive-emotional expressions underlying behavioural or presymptomatic profiles presenting predispositions for health or ill health.

Improving the outcomes of children affected by parental substance abuse: a review of randomized controlled trials

PubMed Central

Calhoun, Stacy; Conner, Emma; Miller, Melodi; Messina, Nena

2015-01-01

Substance abuse is a major public health concern that impacts not just the user but also the user’s family. The effect that parental substance abuse has on children has been given substantial attention over the years. Findings from the literature suggest that children of substance-abusing parents have a high risk of developing physical and mental health and behavioral problems. A number of intervention programs have been developed for parents who have a substance abuse problem. There have also been a number of interventions that have been developed for children who have at least one parent with a substance abuse problem. However, it remains unclear how we can best mitigate the negative effects that parental substance abuse has on children due to the scarcity of evaluations that utilize rigorous methodologies such as experimental designs. The purpose of this study is to review randomized controlled trials of intervention programs targeting parents with substance abuse problems and/or children with at least one parent with a substance abuse problem in order to identify programs that show some promise in improving the behavioral and mental health outcomes of children affected by parental substance abuse. Four randomized controlled trials that met our eligibility criteria were identified using major literature search engines. The findings from this review suggest that interventions that focus on improving parenting practices and family functioning may be effective in reducing problems in children affected by parental substance abuse. However, further research utilizing rigorous methodologies are needed in order to identify other successful interventions that can improve the outcomes of these children long after the intervention has ended. PMID:25670915

Morphology of the Middle Rio Grande from Cochiti Dam to Bernalillo Bridge, New Mexico

Treesearch

Claudia Leon Salazar

1998-01-01

The continuous geomorphologic changes in the Middle Rio Grande in New Mexico have been of interest for many governmental agencies involved with the management and operation of this river system. Due to sedimentation problems along this river, highly developed plans for sediment detention and flood control have been carried out. Cochiti Dam was built as a part of these...

Murphy's law-if anything can go wrong, it will: Problems in phage electron microscopy.

PubMed

Ackermann, Hans-W; Tiekotter, Kenneth L

2012-04-01

The quality of bacteriophage electron microscopy appears to be on a downward course since the 1980s. This coincides with the introduction of digital electron microscopes and a general lowering of standards, possibly due to the disappearance of several world-class electron microscopists The most important problem seems to be poor contrast. Positive staining is frequently not recognized as an undesirable artifact. Phage parts, bacterial debris, and aberrant or damaged phage particles may be misdiagnosed as bacterial viruses. Digital electron microscopes often seem to be operated without magnification control because this is difficult and inconvenient. In summary, most phage electron microscopy problems may be attributed to human failure. Journals are a last-ditch defense and have a heavy responsibility in selecting competent reviewers and rejecting, or not, unsatisfactory articles.

Memory and comprehension deficits in spatial descriptions of children with non-verbal and reading disabilities.

PubMed

Mammarella, Irene C; Meneghetti, Chiara; Pazzaglia, Francesca; Cornoldi, Cesare

2014-01-01

The present study investigated the difficulties encountered by children with non-verbal learning disability (NLD) and reading disability (RD) when processing spatial information derived from descriptions, based on the assumption that both groups should find it more difficult than matched controls, but for different reasons, i.e., due to a memory encoding difficulty in cases of RD and to spatial information comprehension problems in cases of NLD. Spatial descriptions from both survey and route perspectives were presented to 9-12-year-old children divided into three groups: NLD (N = 12); RD (N = 12), and typically developing controls (TD; N = 15); then participants completed a sentence verification task and a memory for locations task. The sentence verification task was presented in two conditions: in one the children could refer to the text while answering the questions (i.e., text present condition), and in the other the text was withdrawn (i.e., text absent condition). Results showed that the RD group benefited from the text present condition, but was impaired to the same extent as the NLD group in the text absent condition, suggesting that the NLD children's difficulty is due mainly to their poor comprehension of spatial descriptions, while the RD children's difficulty is due more to a memory encoding problem. These results are discussed in terms of their implications in the neuropsychological profiles of children with NLD or RD, and the processes involved in spatial descriptions.

A qualitative difference. Patients' views of hospital food service in Iran.

PubMed

Jessri, Mahsa; Mirmiran, Parvin; Jessri, Maryam; Johns, Nick; Rashidkhani, Bahram; Amiri, Parisa; Barfmal, Nasrin; Azizi, Fereidoun

2011-10-01

Undernutrition and food acceptability in hospitals form a worldwide problem, but existing studies offer a predominantly Western perspective. This research investigated inpatients' satisfaction with meals in five Iranian hospitals, using focus group discussions, interviews and meal observations. The main problem areas included food quality and quantity, nutritional control, meal arrangements and staff attitudes. Iran's hospitals follow a Western model, which may be appropriate for medical systems, but is less so for patient feeding, due to budgetary constraints and cultural factors. Understanding patients' experience makes it possible to improve feeding arrangements, with a positive impact upon patients' nutrition. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effect of damping on excitability of high-order normal modes. [for a large space telescope spacecraft

NASA Technical Reports Server (NTRS)

Merchant, D. H.; Gates, R. M.; Straayer, J. W.

1975-01-01

The effect of localized structural damping on the excitability of higher-order large space telescope spacecraft modes is investigated. A preprocessor computer program is developed to incorporate Voigt structural joint damping models in a finite-element dynamic model. A postprocessor computer program is developed to select critical modes for low-frequency attitude control problems and for higher-frequency fine-stabilization problems. The selection is accomplished by ranking the flexible modes based on coefficients for rate gyro, position gyro, and optical sensor, and on image-plane motions due to sinusoidal or random PSD force and torque inputs.

Developing a PLC-friendly state machine model: lessons learned

NASA Astrophysics Data System (ADS)

Pessemier, Wim; Deconinck, Geert; Raskin, Gert; Saey, Philippe; Van Winckel, Hans

2014-07-01

Modern Programmable Logic Controllers (PLCs) have become an attractive platform for controlling real-time aspects of astronomical telescopes and instruments due to their increased versatility, performance and standardization. Likewise, vendor-neutral middleware technologies such as OPC Unified Architecture (OPC UA) have recently demonstrated that they can greatly facilitate the integration of these industrial platforms into the overall control system. Many practical questions arise, however, when building multi-tiered control systems that consist of PLCs for low level control, and conventional software and platforms for higher level control. How should the PLC software be structured, so that it can rely on well-known programming paradigms on the one hand, and be mapped to a well-organized OPC UA interface on the other hand? Which programming languages of the IEC 61131-3 standard closely match the problem domains of the abstraction levels within this structure? How can the recent additions to the standard (such as the support for namespaces and object-oriented extensions) facilitate a model based development approach? To what degree can our applications already take advantage of the more advanced parts of the OPC UA standard, such as the high expressiveness of the semantic modeling language that it defines, or the support for events, aggregation of data, automatic discovery, ... ? What are the timing and concurrency problems to be expected for the higher level tiers of the control system due to the cyclic execution of control and communication tasks by the PLCs? We try to answer these questions by demonstrating a semantic state machine model that can readily be implemented using IEC 61131 and OPC UA. One that does not aim to capture all possible states of a system, but rather one that attempts to organize the course-grained structure and behaviour of a system. In this paper we focus on the intricacies of this seemingly simple task, and on the lessons that we've learned during the development process of such a "PLC-friendly" state machine model.

Effect of job maintenance training program for employees with chronic disease - a randomized controlled trial on self-efficacy, job satisfaction, and fatigue.

PubMed

Varekamp, Inge; Verbeek, Jos H; de Boer, Angela; van Dijk, Frank J H

2011-07-01

Employees with a chronic physical condition may be hampered in job performance due to physical or cognitive limitations, pain, fatigue, psychosocial barriers, or because medical treatment interferes with work. This study investigates the effect of a group-training program aimed at job maintenance. Essential elements of the program are exploration of work-related problems, communication at the workplace, and the development and implementation of solutions. Participants with chronic physical diseases were randomly assigned to the intervention (N=64) or the control group (N=58). Participants were eligible for the study if they had a chronic physical disease, paid employment, experienced work-related problems, and were not on long-term 100% sick leave. Primary outcome measures were self-efficacy in solving work- and disease-related problems (14-70), job dissatisfaction (0-100), fatigue (20-140) and job maintenance measured at 4-, 8-, 12- and 24-month follow-up. We used GLM repeated measures for the analysis. After 24 months, loss to follow-up was 5.7% (7/122). Self-efficacy increased and fatigue decreased significantly more in the experimental than the control group [10 versus 4 points (P=0.000) and 19 versus 8 points (P=0.032), respectively]. Job satisfaction increased more in the experimental group but not significantly [6 versus 0 points (P=0.698)]. Job maintenance was 87% in the experimental and 91% in the control group, which was not a significant difference. Many participants in the control group also undertook actions to solve work-related problems. Empowerment training increases self-efficacy and helps to reduce fatigue complaints, which in the long term could lead to more job maintenance. Better understanding of ways to deal with work-related problems is needed to develop more efficient support for employees with a chronic disease.

A Unified Approach to Adaptive Neural Control for Nonlinear Discrete-Time Systems With Nonlinear Dead-Zone Input.

PubMed

Liu, Yan-Jun; Gao, Ying; Tong, Shaocheng; Chen, C L Philip

2016-01-01

In this paper, an effective adaptive control approach is constructed to stabilize a class of nonlinear discrete-time systems, which contain unknown functions, unknown dead-zone input, and unknown control direction. Different from linear dead zone, the dead zone, in this paper, is a kind of nonlinear dead zone. To overcome the noncausal problem, which leads to the control scheme infeasible, the systems can be transformed into a m -step-ahead predictor. Due to nonlinear dead-zone appearance, the transformed predictor still contains the nonaffine function. In addition, it is assumed that the gain function of dead-zone input and the control direction are unknown. These conditions bring about the difficulties and the complicacy in the controller design. Thus, the implicit function theorem is applied to deal with nonaffine dead-zone appearance, the problem caused by the unknown control direction can be resolved through applying the discrete Nussbaum gain, and the neural networks are used to approximate the unknown function. Based on the Lyapunov theory, all the signals of the resulting closed-loop system are proved to be semiglobal uniformly ultimately bounded. Moreover, the tracking error is proved to be regulated to a small neighborhood around zero. The feasibility of the proposed approach is demonstrated by a simulation example.

Reducing Energy Degradation Due to Back-bombardment Effect with Modulated RF Input in S-band Thermionic RF Gun

NASA Astrophysics Data System (ADS)

Kii, Toshiteru; Nakai, Yoko; Fukui, Toshio; Zen, Heishun; Kusukame, Kohichi; Okawachi, Norihito; Nakano, Masatsugu; Masuda, Kai; Ohgaki, Hideaki; Yoshikawa, Kiyoshi; Yamazaki, Tetsuo

2007-01-01

Energy degradation due to back-bombardment effect is quite serious to produce high-brightness electron beam with long macro-pulse with thermionic rf gun. To avoid the back-bombardment problem, a laser photo cathode is used at many FEL facilities, but usually it costs high and not easy to operate. Thus we have studied long pulse operation of the rf gun with thermionic cathode, which is inexpensive and easy to operate compared to the photocathode rf gun. In this work, to reduce the energy degradation, we controlled input rf power amplitude by controlling pulse forming network of the power modulator for klystron. We have successfully increased the pulse duration up to 4 μs by increasing the rf power from 7.8 MW to 8.5 MW during the macro pulse.

Boundary-layer receptivity due to a wall suction and control of Tollmien-Schlichting waves

NASA Technical Reports Server (NTRS)

Bodonyi, R. J.; Duck, P. W.

1992-01-01

A numerical study of the generation of Tollmien-Schlichting (T-S) waves due to the interaction between a small free-stream disturbance and a small localized suction slot on an otherwise flat surface was carried out using finite difference methods. The nonlinear steady flow is of the viscous-inviscid interactive type while the unsteady disturbed flow is assumed to be governed by the Navier-Stokes equations linearized about this flow. Numerical solutions illustrate the growth or decay of T-S waves generated by the interaction between the free-stream disturbance and the suction slot, depending on the value of the scaled Strouhal number. An important result of this receptivity problem is the numerical determination of the amplitude of the T-S waves and the demonstration of the possible active control of the growth of T-S waves.

Boundary-layer receptivity due to a wall suction and control of Tollmien-Schlichting waves

NASA Technical Reports Server (NTRS)

Bodonyi, R. J.; Duck, P. W.

1990-01-01

A numerical study of the generation of Tollmien-Schlichting (T-S) waves due to the interaction between a small free-stream disturbance and a small localized suction slot on an otherwise flat surface was carried out using finite difference methods. The nonlinear steady flow is of the viscous-inviscid interactive type while the unsteady disturbed flow is assumed to be governed by the Navier-Stokes equations linearized about this flow. Numerical solutions illustrate the growth or decay of T-S waves generated by the interaction between the free-stream disturbance and the suction slot, depending on the value of the scaled Strouhal number. An important result of this receptivity problem is the numerical determination of the amplitude of the T-S waves and the demonstration of the possible active control of the growth of T-S waves.

Plug-and-play measurement-device-independent quantum key distribution

NASA Astrophysics Data System (ADS)

Choi, Yujun; Kwon, Osung; Woo, Minki; Oh, Kyunghwan; Han, Sang-Wook; Kim, Yong-Su; Moon, Sung

2016-03-01

Quantum key distribution (QKD) guarantees unconditional communication security based on the laws of quantum physics. However, practical QKD suffers from a number of quantum hackings due to the device imperfections. From the security standpoint, measurement-device-independent quantum key distribution (MDI-QKD) is in the limelight since it eliminates all the possible loopholes in detection. Due to active control units for mode matching between the photons from remote parties, however, the implementation of MDI-QKD is highly impractical. In this paper, we propose a method to resolve the mode matching problem while minimizing the use of active control units. By introducing the plug-and-play (P&P) concept into MDI-QKD, the indistinguishability in spectral and polarization modes between photons can naturally be guaranteed. We show the feasibility of P&P MDI-QKD with a proof-of-principle experiment.

Extended state observer-based motion synchronisation control for hybrid actuation system of large civil aircraft

NASA Astrophysics Data System (ADS)

Wang, Xingjian; Shi, Cun; Wang, Shaoping

2017-07-01

Hybrid actuation system with dissimilar redundant actuators, which is composed of a hydraulic actuator (HA) and an electro-hydrostatic actuator (EHA), has been applied on modern civil aircraft to improve the reliability. However, the force fighting problem arises due to different dynamic performances between HA and EHA. This paper proposes an extended state observer (ESO)-based motion synchronisation control method. To cope with the problem of unavailability of the state signals, the well-designed ESO is utilised to observe the HA and EHA state variables which are unmeasured. In particular, the extended state of ESO can estimate the lumped effect of the unknown external disturbances acting on the control surface, the nonlinear dynamics, uncertainties, and the coupling term between HA and EHA. Based on the observed states of ESO, motion synchronisation controllers are presented to make HA and EHA to simultaneously track the desired motion trajectories, which are generated by a trajectory generator. Additionally, the unknown disturbances and the coupling terms can be compensated by using the extended state of the proposed ESO. Finally, comparative simulation results indicate that the proposed ESO-based motion synchronisation controller can achieve great force fighting reduction between HA and EHA.

Adaptive NN controller design for a class of nonlinear MIMO discrete-time systems.

PubMed

Liu, Yan-Jun; Tang, Li; Tong, Shaocheng; Chen, C L Philip

2015-05-01

An adaptive neural network tracking control is studied for a class of multiple-input multiple-output (MIMO) nonlinear systems. The studied systems are in discrete-time form and the discretized dead-zone inputs are considered. In addition, the studied MIMO systems are composed of N subsystems, and each subsystem contains unknown functions and external disturbance. Due to the complicated framework of the discrete-time systems, the existence of the dead zone and the noncausal problem in discrete-time, it brings about difficulties for controlling such a class of systems. To overcome the noncausal problem, by defining the coordinate transformations, the studied systems are transformed into a special form, which is suitable for the backstepping design. The radial basis functions NNs are utilized to approximate the unknown functions of the systems. The adaptation laws and the controllers are designed based on the transformed systems. By using the Lyapunov method, it is proved that the closed-loop system is stable in the sense that the semiglobally uniformly ultimately bounded of all the signals and the tracking errors converge to a bounded compact set. The simulation examples and the comparisons with previous approaches are provided to illustrate the effectiveness of the proposed control algorithm.

Existence and characterization of optimal control in mathematics model of diabetics population

NASA Astrophysics Data System (ADS)

Permatasari, A. H.; Tjahjana, R. H.; Udjiani, T.

2018-03-01

Diabetes is a chronic disease with a huge burden affecting individuals and the whole society. In this paper, we constructed the optimal control mathematical model by applying a strategy to control the development of diabetic population. The constructed mathematical model considers the dynamics of disabled people due to diabetes. Moreover, an optimal control approach is proposed in order to reduce the burden of pre-diabetes. Implementation of control is done by preventing the pre-diabetes develop into diabetics with and without complications. The existence of optimal control and characterization of optimal control is discussed in this paper. Optimal control is characterized by applying the Pontryagin minimum principle. The results indicate that there is an optimal control in optimization problem in mathematics model of diabetic population. The effect of the optimal control variable (prevention) is strongly affected by the number of healthy people.

Active control of panel vibrations induced by a boundary layer flow

NASA Technical Reports Server (NTRS)

Chow, Pao-Liu

1995-01-01

The problems of active and passive control of sound and vibration has been investigated by many researchers for a number of years. However, few of the articles are concerned with the sound and vibration with flow-structure interaction. Experimental and numerical studies on the coupling between panel vibration and acoustic radiation due to flow excitation have been done by Maestrello and his associates at NASA/Langley Research Center. Since the coupled system of nonlinear partial differential equations is formidable, an analytical solution to the full problem seems impossible. For this reason, we have to simplify the problem to that of the nonlinear panel vibration induced by a uniform flow or a boundary-layer flow with a given wall pressure distribution. Based on this simplified model, we have been able to consider the control and stabilization of the nonlinear panel vibration, which have not been treated satisfactorily by other authors. Although the sound radiation has not been included, the vibration suppression will clearly reduce the sound radiation power from the panel. The major research findings are presented in three sections. In section two we describe results on the boundary control of nonlinear panel vibration, with or without flow excitation. Sections three and four are concerned with some analytical and numerical results in the optimal control of the linear and nonlinear panel vibrations, respectively, excited by the flow pressure fluctuations. Finally, in section five, we draw some conclusions from research findings.

The Scatter Search Based Algorithm to Revenue Management Problem in Broadcasting Companies

NASA Astrophysics Data System (ADS)

Pishdad, Arezoo; Sharifyazdi, Mehdi; Karimpour, Reza

2009-09-01

The problem under question in this paper which is faced by broadcasting companies is how to benefit from a limited advertising space. This problem is due to the stochastic behavior of customers (advertiser) in different fare classes. To address this issue we propose a mathematical constrained nonlinear multi period model which incorporates cancellation and overbooking. The objective function is to maximize the total expected revenue and our numerical method performs it by determining the sales limits for each class of customer to present the revenue management control policy. Scheduling the advertising spots in breaks is another area of concern and we consider it as a constraint in our model. In this paper an algorithm based on Scatter search is developed to acquire a good feasible solution. This method uses simulation over customer arrival and in a continuous finite time horizon [0, T]. Several sensitivity analyses are conducted in computational result for depicting the effectiveness of proposed method. It also provides insight into better results of considering revenue management (control policy) compared to "no sales limit" policy in which sooner demand will served first.

Exact and Heuristic Algorithms for Runway Scheduling

NASA Technical Reports Server (NTRS)

Malik, Waqar A.; Jung, Yoon C.

2016-01-01

This paper explores the Single Runway Scheduling (SRS) problem with arrivals, departures, and crossing aircraft on the airport surface. Constraints for wake vortex separations, departure area navigation separations and departure time window restrictions are explicitly considered. The main objective of this research is to develop exact and heuristic based algorithms that can be used in real-time decision support tools for Air Traffic Control Tower (ATCT) controllers. The paper provides a multi-objective dynamic programming (DP) based algorithm that finds the exact solution to the SRS problem, but may prove unusable for application in real-time environment due to large computation times for moderate sized problems. We next propose a second algorithm that uses heuristics to restrict the search space for the DP based algorithm. A third algorithm based on a combination of insertion and local search (ILS) heuristics is then presented. Simulation conducted for the east side of Dallas/Fort Worth International Airport allows comparison of the three proposed algorithms and indicates that the ILS algorithm performs favorably in its ability to find efficient solutions and its computation times.

Flow/Soot-Formation Interactions in Nonbuoyant Laminar Diffusion Flames

NASA Technical Reports Server (NTRS)

Dai, Z.; Faeth, G. M.

1999-01-01

Nonpremixed (diffusion) flames are attractive for practical applications because they avoid the stability, autoignition, flashback, etc. problems of premixed flames. Unfortunately, soot formation in practical hydrocarbon-fueled diffusion flames reduces their attractiveness due to widely-recognized public health and combustor durability problems of soot emissions. For example, more deaths are attributed to the emission of soot (15,000-60,000 deaths annually in the U.S. alone) than any other combustion-generated pollutant. In addition, continuum radiation from soot-containing flames is the principle heat load to combustor components and is mainly responsible for engine durability problems of aircraft and gas turbine engines. As a result, there is considerable interest in controlling both soot concentrations within flames and soot emissions from flames. Thus, the objective of the present investigation is to study ways to control soot formation in diffusion flames by manipulating the mixing process between the fuel and oxidant streams. In order to prevent the intrusion of gravity from masking flow properties that reduce soot formation in practical flames (where effects of gravity are small), methods developed during past work will be exploited to minimize effects of buoyant motion.

From mother to child: orbitofrontal cortex gyrification and changes of drinking behaviour during adolescence.

PubMed

Kühn, Simone; Witt, Charlotte; Banaschewski, Tobias; Barbot, Alexis; Barker, Gareth J; Büchel, Christian; Conrod, Patricia J; Flor, Herta; Garavan, Hugh; Ittermann, Bernd; Mann, Karl; Martinot, Jean-Luc; Paus, Tomas; Rietschel, Marcella; Smolka, Michael N; Ströhle, Andreas; Brühl, Rüdiger; Schumann, Gunter; Heinz, Andreas; Gallinat, Jürgen

2016-05-01

Adolescence is a common time for initiation of alcohol use and alcohol use disorders. Importantly, the neuro-anatomical foundation for later alcohol-related problems may already manifest pre-natally, particularly due to smoking and alcohol consumption during pregnancy. In this context, cortical gyrification is an interesting marker of neuronal development but has not been investigated as a risk factor for adolescent alcohol use. On magnetic resonance imaging scans of 595 14-year-old adolescents from the IMAGEN sample, we computed whole-brain mean curvature indices to predict change in alcohol-related problems over the following 2 years. Change of alcohol use-related problems was significantly predicted from mean curvature in left orbitofrontal cortex (OFC). Less gyrification of OFC was associated with an increase in alcohol use-related problems over the next 2 years. Moreover, lower gyrification in left OFC was related to pre-natal alcohol exposure, whereas maternal smoking during pregnancy had no effect. Current alcohol use-related problems of the biological mother had no effect on offsprings' OFC gyrification or drinking behaviour. The data support the idea that alcohol consumption during pregnancy mediates the development of neuro-anatomical phenotypes, which in turn constitute a risk factor for increasing problems due to alcohol consumption in a vulnerable stage of life. Maternal smoking during pregnancy or current maternal alcohol/nicotine consumption had no significant effect. The OFC mediates behaviours known to be disturbed in addiction, namely impulse control and reward processing. The results stress the importance of pre-natal alcohol exposure for later increases in alcohol use-related problems, mediated by structural brain characteristics. © 2015 Society for the Study of Addiction.

Political economy of tobacco control policy on public health in Japan.

PubMed

Desapriya, E B R; Iwase, Nobutada; Shimizu, Shinji

2003-02-01

Tobacco use, particularly smoking, remains the number one cause of preventable disease and mortality in Japan. This review of the tobacco control policy and public health is the first to offer a composite review of the subject within Japan. This review attempts to evaluate the most important aspects of the current political economy of the tobacco control policy, and concludes that more effective control policies must be employed to minimize the impact of smoking on the public's health in Japan. Further the article attempts to place the approaches in the larger context of tobacco control, providing a vision for the future of tobacco prevention and control based on current knowledge. Tobacco use will remain the leading cause of preventable illness and death in Japan, until tobacco prevention and control efforts are commensurate with the harm caused by tobacco. Taken together, the results of various studies have clearly shown that control measures can influence tobacco smoking patterns, and in turn, the rate of tobacco-related problems. Government tobacco taxes have not kept pace with inflation for years. Availability of tobacco is virtually unlimited with easy access and the prices being very low due to the strong currency of Japan. Thus Japan must be one of the most tobacco accessible countries. It is important to ensure that people are not conditioned to smoke tobacco by an unduly favourable economic and commercial environment. For that reason, prevention advocates have called for substantial regulation of tobacco products and appeal for both tobacco tax increases and tobacco taxes to be indexed to inflation. In this review, present tobacco related public health policies in Japan are discussed with implication for prevention of tobacco related problems. Continued research in this area will be necessary to determine the most effective policies of reducing tobacco related problems in Japan.

Evaluation of the Effects of Hidden Node Problems in IEEE 802.15.7 Uplink Performance

PubMed Central

Ley-Bosch, Carlos; Alonso-González, Itziar; Sánchez-Rodríguez, David; Ramírez-Casañas, Carlos

2016-01-01

In the last few years, the increasing use of LEDs in illumination systems has been conducted due to the emergence of Visible Light Communication (VLC) technologies, in which data communication is performed by transmitting through the visible band of the electromagnetic spectrum. In 2011, the Institute of Electrical and Electronics Engineers (IEEE) published the IEEE 802.15.7 standard for Wireless Personal Area Networks based on VLC. Due to limitations in the coverage of the transmitted signal, wireless networks can suffer from the hidden node problems, when there are nodes in the network whose transmissions are not detected by other nodes. This problem can cause an important degradation in communications when they are made by means of the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) access control method, which is used in IEEE 802.15.7 This research work evaluates the effects of the hidden node problem in the performance of the IEEE 802.15.7 standard We implement a simulator and analyze VLC performance in terms of parameters like end-to-end goodput and message loss rate. As part of this research work, a solution to the hidden node problem is proposed, based on the use of idle patterns defined in the standard. Idle patterns are sent by the network coordinator node to communicate to the other nodes that there is an ongoing transmission. The validity of the proposed solution is demonstrated with simulation results. PMID:26861352

Evaluation of the Effects of Hidden Node Problems in IEEE 802.15.7 Uplink Performance.

PubMed

Ley-Bosch, Carlos; Alonso-González, Itziar; Sánchez-Rodríguez, David; Ramírez-Casañas, Carlos

2016-02-06

In the last few years, the increasing use of LEDs in illumination systems has been conducted due to the emergence of Visible Light Communication (VLC) technologies, in which data communication is performed by transmitting through the visible band of the electromagnetic spectrum. In 2011, the Institute of Electrical and Electronics Engineers (IEEE) published the IEEE 802.15.7 standard for Wireless Personal Area Networks based on VLC. Due to limitations in the coverage of the transmitted signal, wireless networks can suffer from the hidden node problems, when there are nodes in the network whose transmissions are not detected by other nodes. This problem can cause an important degradation in communications when they are made by means of the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) access control method, which is used in IEEE 802.15.7 This research work evaluates the effects of the hidden node problem in the performance of the IEEE 802.15.7 standard We implement a simulator and analyze VLC performance in terms of parameters like end-to-end goodput and message loss rate. As part of this research work, a solution to the hidden node problem is proposed, based on the use of idle patterns defined in the standard. Idle patterns are sent by the network coordinator node to communicate to the other nodes that there is an ongoing transmission. The validity of the proposed solution is demonstrated with simulation results.

Efficient control-channel multifailure management mechanism in GMPLS-based optical networks

NASA Astrophysics Data System (ADS)

Muñoz, Raül; Martínez, Ricardo; Junyent, Gabriel

2006-12-01

In generalized multiprotocol label switching (GMPLS) architecture, the control channels between each pair of optical nodes are not forced to use the same physical link as the data/transport channels. The problem arises when, due to the fact of allowing the control channels to be physically diverse from the associated data links, there may not be any active control channels available while data channels are still in use. Control-channel faults should not have a service impact on the existing connections; that is, a link that is carrying data traffic must not be torn down because the control channel is no longer available. But, due to the lack of the control channel, the active traffic that is using the data link may no longer be guaranteed with the same level of recovery service (protection or restoration). Under these circumstances the link must be considered to be in a degraded state. This means that routing and signaling should be notified that new connections are not accepted and the link is advertised with no unreserved resources. For this purpose, here we propose a control-channel multifailure management mechanism involving routing, signaling, and link management with extended GMPLS-based protocol extensions to keep the same level of service (in terms of provisioning and recovery) when a link is in the degraded state.

Adjoint Method and Predictive Control for 1-D Flow in NASA Ames 11-Foot Transonic Wind Tunnel

NASA Technical Reports Server (NTRS)

Nguyen, Nhan; Ardema, Mark

2006-01-01

This paper describes a modeling method and a new optimal control approach to investigate a Mach number control problem for the NASA Ames 11-Foot Transonic Wind Tunnel. The flow in the wind tunnel is modeled by the 1-D unsteady Euler equations whose boundary conditions prescribe a controlling action by a compressor. The boundary control inputs to the compressor are in turn controlled by a drive motor system and an inlet guide vane system whose dynamics are modeled by ordinary differential equations. The resulting Euler equations are thus coupled to the ordinary differential equations via the boundary conditions. Optimality conditions are established by an adjoint method and are used to develop a model predictive linear-quadratic optimal control for regulating the Mach number due to a test model disturbance during a continuous pitch

An air-coupled actuator array for active modal control of timpani

NASA Astrophysics Data System (ADS)

Rollow, Douglas; Sparrow, Victor W.; Swanson, David C.

2005-09-01

The timbral characteristics of kettledrums can be described by a modal formulation of the vibration of a thin, air-loaded membrane. Modification of the modal time history can be brought about with the use of a control system which has independent influence on each structural mode. By replacing the usual kettle with a shallow chamber and a planar array of piston sources, a modal controller is created when driving the sources in appropriate linear combinations. A theoretical formulation of active control of structural vibration by means of fluid-coupled actuators is expressed, and a Boundary Element simulation provides insight to the coupled modes, independence of control, and constraints due to the geometry of the chamber. Advantages and limitations of this type of control source to general problems in actively controlled musical instruments are explored.

Orbiting space debris: Dangers, measurement, and mitigation

NASA Astrophysics Data System (ADS)

McNutt, Ross T.

1992-01-01

Space debris is a growing environmental problem. Accumulation of objects in Earth orbit threatens space systems through the possibility of collisions and runaway debris multiplication. The amount of debris in orbit is uncertain due to the lack of information on the population of debris between 1 and 10 centimeters diameter. Collisions with debris even smaller than 1 cm can be catastrophic due to the high orbital velocities involved. Research efforts are under way at NASA, Unites States Space Command and the Air Force Phillips Laboratory to detect and catalog the debris population in near-Earth space. Current international and national laws are inadequate to control the proliferation of space debris. Space debris is a serious problem with large economic, military, technical, and diplomatic components. Actions need to be taken now for the following reasons: determine the full extent of the orbital debris problem; accurately predict the future evolution of the debris population; decide the extent of the debris mitigation procedures required; implement these policies on a global basis via an international treaty. Action must be initiated now, before the the loss of critical space systems such as the Space Shuttle or the Space Station.

Development of a Pneumatic Robot for MRI-guided Transperineal Prostate Biopsy and Brachytherapy: New Approaches

PubMed Central

Song, Sang-Eun; Cho, Nathan B.; Fischer, Gregory; Hata, Nobuhito; Tempany, Clare; Fichtinger, Gabor; Iordachita, Iulian

2011-01-01

Magnetic Resonance Imaging (MRI) guided prostate biopsy and brachytherapy has been introduced in order to enhance the cancer detection and treatment. For the accurate needle positioning, a number of robotic assistants have been developed. However, problems exist due to the strong magnetic field and limited workspace. Pneumatically actuated robots have shown the minimum distraction in the environment but the confined workspace limits optimal robot design and thus controllability is often poor. To overcome the problem, a simple external damping mechanism using timing belts was sought and a 1-DOF mechanism test result indicated sufficient positioning accuracy. Based on the damping mechanism and modular system design approach, a new workspace-optimized 4-DOF parallel robot was developed for the MRI-guided prostate biopsy and brachytherapy. A preliminary evaluation of the robot was conducted using previously developed pneumatic controller and satisfying results were obtained. PMID:21399734

Incorporating uncertainty in watershed management decision-making: A mercury TMDL case study

USGS Publications Warehouse

Labiosa, W.; Leckie, J.; Shachter, R.; Freyberg, D.; Rytuba, J.; ,

2005-01-01

Water quality impairment due to high mercury fish tissue concentrations and high mercury aqueous concentrations is a widespread problem in several sub-watersheds that are major sources of mercury to the San Francisco Bay. Several mercury Total Maximum Daily Load regulations are currently being developed to address this problem. Decisions about control strategies are being made despite very large uncertainties about current mercury loading behavior, relationships between total mercury loading and methyl mercury formation, and relationships between potential controls and mercury fish tissue levels. To deal with the issues of very large uncertainties, data limitations, knowledge gaps, and very limited State agency resources, this work proposes a decision analytical alternative for mercury TMDL decision support. The proposed probabilistic decision model is Bayesian in nature and is fully compatible with a "learning while doing" adaptive management approach. Strategy evaluation, sensitivity analysis, and information collection prioritization are examples of analyses that can be performed using this approach.

Inherited haemoglobin disorders: an increasing global health problem.

PubMed Central

Weatherall, D. J.; Clegg, J. B.

2001-01-01

Despite major advances in our understanding of the molecular pathology, pathophysiology, and control and management of the inherited disorders of haemoglobin, thousands of infants and children with these diseases are dying through lack of appropriate medical care. This problem will undoubtedly increase over the next 20 years because, as the result of a reduction in childhood mortality due to infection and malnutrition, more babies with haemoglobin disorders will survive to present for treatment. Although WHO and various voluntary agencies have tried to disseminate information about these diseases, they are rarely mentioned as being sufficiently important to be included in setting health care priorities for the future. It takes considerable time to establish expertise in developing programmes for the control and management of these conditions, and the lessons learned in developed countries will need to be transmitted to those countries in which they occur at a high frequency. PMID:11545326

Crystal growth of device quality GaAs in space

NASA Technical Reports Server (NTRS)

Gatos, H. C.; Lagowski, J.

1986-01-01

It was established that the findings on elemental semiconductors Ge and Si regarding crystal growth, segregation, chemical composition, defect interactions, and materials properties-electronic properties relationships are not necessarily applicable to GaAs (and to other semiconductor compounds). In many instances totally unexpected relationships were found to prevail. It was further established that in compound semiconductors with a volatile constituent, control of stoichiometry is far more critical than any other crystal growth parameter. It was also shown that, due to suppression of nonstoichiometric fluctuations, the advantages of space for growth of semiconductor compounds extend far beyond those observed in elemental semiconductors. A novel configuration was discovered for partial confinement of GaAs melt in space which overcomes the two major problems associated with growth of semiconductors in total confinement. They are volume expansion during solidification and control of pressure of the volatile constituent. These problems are discussed in detail.

Effective management of low back pain: it’s time to accept the evidence

PubMed Central

Manga, Pran; Angus, Douglas E; Swan, William R

1993-01-01

Low back pain is a ubiquitous and economically costly problem. Unfortunately, the clinical management of low back pain is not yet well understood. Chiropractic management of back pain, long the black sheep of back care, has undergone a transition and is now a more respected and understood alternative to conservative medical care, itself under increased scrutiny due to unsatisfactory outcomes and unacceptable iatrogenic side effects. The substantial amount of clinical and related research on the effectiveness of manipulation for low back pain is summarized here from a larger study, divided into randomized control trials, case-control trials, meta-analyses and descriptive studies. The chiropractic management of low back pain is found to be a more effective way of dealing with this medical, social and economic problem. It is suggested that greater utilization of chiropractors be encouraged such that the “right people are doing the right things at the right time”.

The establishment and application of direct coupled electrostatic-structural field model in electrostatically controlled deployable membrane antenna

NASA Astrophysics Data System (ADS)

Gu, Yongzhen; Duan, Baoyan; Du, Jingli

2018-05-01

The electrostatically controlled deployable membrane antenna (ECDMA) is a promising space structure due to its low weight, large aperture and high precision characteristics. However, it is an extreme challenge to describe the coupled field between electrostatic and membrane structure accurately. A direct coupled method is applied to solve the coupled problem in this paper. Firstly, the membrane structure and electrostatic field are uniformly described by energy, considering the coupled problem is an energy conservation phenomenon. Then the direct coupled electrostatic-structural field governing equilibrium equations are obtained by energy variation approach. Numerical results show that the direct coupled method improves the computing efficiency by 36% compared with the traditional indirect coupled method with the same level accuracy. Finally, the prototype has been manufactured and tested and the ECDMA finite element simulations show good agreement with the experiment results as the maximum surface error difference is 6%.

Dynamic programming methods for concurrent design and dynamic allocation of vehicles embedded in a system-of-systems

NASA Astrophysics Data System (ADS)

Nusawardhana

2007-12-01

Recent developments indicate a changing perspective on how systems or vehicles should be designed. Such transition comes from the way decision makers in defense related agencies address complex problems. Complex problems are now often posed in terms of the capabilities desired, rather than in terms of requirements for a single systems. As a result, the way to provide a set of capabilities is through a collection of several individual, independent systems. This collection of individual independent systems is often referred to as a "System of Systems'' (SoS). Because of the independent nature of the constituent systems in an SoS, approaches to design an SoS, and more specifically, approaches to design a new system as a member of an SoS, will likely be different than the traditional design approaches for complex, monolithic (meaning the constituent parts have no ability for independent operation) systems. Because a system of system evolves over time, this simultaneous system design and resource allocation problem should be investigated in a dynamic context. Such dynamic optimization problems are similar to conventional control problems. However, this research considers problems which not only seek optimizing policies but also seek the proper system or vehicle to operate under these policies. This thesis presents a framework and a set of analytical tools to solve a class of SoS problems that involves the simultaneous design of a new system and allocation of the new system along with existing systems. Such a class of problems belongs to the problems of concurrent design and control of a new systems with solutions consisting of both optimal system design and optimal control strategy. Rigorous mathematical arguments show that the proposed framework solves the concurrent design and control problems. Many results exist for dynamic optimization problems of linear systems. In contrary, results on optimal nonlinear dynamic optimization problems are rare. The proposed framework is equipped with the set of analytical tools to solve several cases of nonlinear optimal control problems: continuous- and discrete-time nonlinear problems with applications on both optimal regulation and tracking. These tools are useful when mathematical descriptions of dynamic systems are available. In the absence of such a mathematical model, it is often necessary to derive a solution based on computer simulation. For this case, a set of parameterized decision may constitute a solution. This thesis presents a method to adjust these parameters based on the principle of stochastic approximation simultaneous perturbation using continuous measurements. The set of tools developed here mostly employs the methods of exact dynamic programming. However, due to the complexity of SoS problems, this research also develops suboptimal solution approaches, collectively recognized as approximate dynamic programming solutions, for large scale problems. The thesis presents, explores, and solves problems from an airline industry, in which a new aircraft is to be designed and allocated along with an existing fleet of aircraft. Because the life cycle of an aircraft is on the order of 10 to 20 years, this problem is to be addressed dynamically so that the new aircraft design is the best design for the fleet over a given time horizon.

Travel-related health risks in moderately and severely immunocompromised patients: a case-control study.

PubMed

Dekkiche, Souad; de Vallière, Serge; D'Acremont, Valérie; Genton, Blaise

2016-03-01

The number of immunocompromised persons travelling to tropical countries is increasing. The hypothesis is that this population is at increased risk of travel-related health problems but there are few data to support it. The objective was to assess the risk of travel-related health problems in immunocompromised persons when compared with the general population of travellers. A retrospective matched case-control study was performed. Cases were moderately or severely immunocompromised persons travelling to tropical countries and controls were non-immunocompromised persons, matched for demographic and travel characteristics. All participants responded to a phone questionnaire, asking them about any health problem they may have encountered while travelling or during the month following their return. The primary outcome was the incidence of a significant clinical event defined as repatriation, hospitalization during the travel or during the month following the return if due to a travel-related health problem and medical consultations during the trip. One hundred and sixteen moderately or severely immunocompromised cases [HIV infection (15), active cancer (25), splenectomized (20), solid organ transplant recipients (4) and use of systemic immunosuppressive medication (52)] and 116 controls were included. Incidence rates of significant clinical events were higher in immunocompromised travellers (9/116, 7.8%) than in controls (2/116, 1.7%) [OR = 4.8 , 95% CI 1.01-22.70; P = 0.048]. Most cases were related to infectious diseases (5/9, 55.5%), others were pulmonary embolism (2/9, 22%), inflammatory disease and trauma (1/9, 11.1% each). There was no significant difference between the two groups regarding common health problems. Moderately and severely immunocompromised travellers are at increased risk of developing a serious health problem during or after a trip in a tropical country. They should be well informed about the specific risks they are particularly prone to. Travel medicine health professionals should favour effective preventive measures for immunocompromised travellers and envisage stand-by antibiotic treatment. © International Society of Travel Medicine, 2016. All rights reserved. Published by Oxford University Press. For permissions, please e-mail: journals.permissions@oup.com.

Study of twenty preparations of human albumin solution which failed in quality control testing due to elevated sodium content, a poor internal quality control at manufacturing unit.

PubMed

Prasad, J P; Madhu, Y; Singh, Surinder; Soni, G R; Agnihotri, N; Singh, Varsha; Kumar, Pradeep; Jain, Nidhi; Prakash, Anu; Singh, Varun

2016-11-01

Current study is conducted in our laboratory due to failure in quality control testing of twenty batches of Human Albumin solution in which sodium content is higher than the prescribed limit. These batches are received in short duration from indigenous manufacturer and is the first incident of failure of Human albumin preparation in sodium content of manufacturer. On request of manufacturer, study is conducted to rule out the cause. Repeat testing of each out of specification batch is conducted and a trend analysis is drawn between our findings and manufacturer's results, also study of trend analysis of manufacturer for the last one year. Trend analysis data indicated towards poor consistency of batches with major shift at various time intervals in sodium content of human albumin preparation. Further analysis rule out that non-traceable quality of standard used in the internal quality control testing by manufacturer is the root cause of the problem. Copyright © 2016 International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.

A Children of Twins Study of parental divorce and offspring psychopathology.

PubMed

D'Onofrio, Brian M; Turkheimer, Eric; Emery, Robert E; Maes, Hermine H; Silberg, Judy; Eaves, Lindon J

2007-07-01

Although parental divorce is associated with increased substance use and internalizing problems, experiencing the separation of one's parents may not cause these outcomes. The relations may be due to genetic or environmental selection factors, characteristics that lead to both marital separation and offspring functioning. We used the Children of Twins (CoT) Design to explore whether unmeasured genetic or environmental factors related to the twin parent, and measured characteristics of both parents, account for the association between parental divorce and offspring substance use and internalizing problems. The association between parental divorce and offspring substance use problems remained robust when controlling for genetic and environmental risk from the twin parent associated with parental divorce, and measured characteristics of both parents. The results do not prove, but are consistent with, a causal connection. In contrast, the analyses suggest that shared genetic liability in parents and their offspring accounts for the increased risk of internalizing problems in adult offspring from divorced families. The study illustrates that unmeasured genetic and environmental selection factors must be considered when studying parental divorce. In explaining associations between parental divorce and young-adult adjustment, our evidence suggests that selection versus causal mechanisms may operate differently for substance abuse (a causal relation) and internalizing problems (an artifact of selection). The CoT design only controls for the genetic and environmental characteristics of one parent; thus, additional genetically informed analyses are needed.

Magnetic Control of Hypersonic Flow

NASA Astrophysics Data System (ADS)

Poggie, Jonathan; Gaitonde, Datta

2000-11-01

Electromagnetic control is an appealing possibility for mitigating the thermal loads that occur in hypersonic flight, in particular for the case of atmospheric entry. There was extensive research on this problem between about 1955 and 1970,(M. F. Romig, ``The Influence of Electric and Magnetic Fields on Heat Transfer to Electrically Conducting Fluids,'' \\underlineAdvances In Heat Transfer), Vol. 1, Academic Press, NY, 1964. and renewed interest has arisen due to developments in the technology of super-conducting magnets and the understanding of the physics of weakly-ionized, non-equilibrium plasmas. In order to examine the physics of this problem, and to evaluate the practicality of electromagnetic control in hypersonic flight, we have developed a computer code to solve the three-dimensional, non-ideal magnetogasdynamics equations. We have applied the code to the problem of magnetically-decelerated hypersonic flow over a sphere, and observed a reduction, with an applied dipole field, in heat flux and skin friction near the nose of the body, as well as an increase in shock standoff distance. The computational results compare favorably with the analytical predictions of Bush.(W. B. Bush, ``Magnetohydrodynamic-Hypersonic Flow Past a Blunt Body'', Journal of the Aero/Space Sciences, Vol. 25, No. 11, 1958; ``The Stagnation-Point Boundary Layer in the Presence of an Applied Magnetic Field'', Vol. 28, No. 8, 1961.)

Influence of Hall Effect on Magnetic Control of Stagnation Point Heat Transfer

NASA Astrophysics Data System (ADS)

Poggie, Jonathan; Gaitonde, Datta

2001-11-01

Electromagnetic control is an appealing possibility for mitigating the thermal loads that occur in hypersonic flight. There was extensive research on this technique in the past (up to about 1970), but enthusiasm waned because of problems of system cost and weight. Renewed interest has arisen recently due to developments in the technology of super-conducting magnets and the understanding of the physics of weakly-ionized, non-equilibrium plasmas. A problem of particular interest is the reduction of stagnation point heating during atmospheric entry by magnetic deceleration of the flow in the shock layer. For the case of hypersonic flow over a sphere, a reduction in heat flux has been observed with the application of a dipole magnetic field (Poggie and Gaitonde, AIAA Paper 2001-0196). The Hall effect has a detrimental influence on this control scheme, tending to rotate the current vector out of the circumferential direction and to reduce the impact of the applied magnetic field on the fluid. In the present work we re-examine this problem by using modern computational methods to simulate flow past a hemispherical-nosed vehicle in which a axially-oriented magnetic dipole has been placed. The deleterious effects of the Hall current are characterized, and are observed to diminish when the surface of the vehicle is conducting.

Flight data analysis and further development of variable-conductance heat pipes. [for aircraft control

NASA Technical Reports Server (NTRS)

Enginer, J. E.; Luedke, E. E.; Wanous, D. J.

1976-01-01

Continuing efforts in large gains in heat-pipe performance are reported. It was found that gas-controlled variable-conductance heat pipes can perform reliably for long periods in space and effectively provide temperature stabilization for spacecraft electronics. A solution was formulated that allows the control gas to vent through arterial heat-pipe walls, thus eliminating the problem of arterial failure under load, due to trace impurities of noncondensable gas trapped in an arterial bubble during priming. This solution functions well in zero gravity. Another solution was found that allows priming at a much lower fluid charge. A heat pipe with high capacity, with close temperature control of the heat source and independent of large variations in sink temperature was fabricated.

Development of a Laboratory for Improving Communication between Air Traffic Controllers and Pilots

NASA Technical Reports Server (NTRS)

Brammer, Anthony

2003-01-01

Runway incursions and other surface incidents are known to be significant threats to aviation safety and efficiency. Though the number of near mid-air collisions in U.S. air space has remained unchanged during the last five years, the number of runway incursions has increased and they are almost all due to human error. The three most common factors contributing to air traffic controller and pilot error in airport operations include two that involve failed auditory communication. This project addressed the problems of auditory communication in air traffic control from an acoustical standpoint, by establishing an acoustics laboratory designed for this purpose and initiating research into selected topics that show promise for improving voice communications between air traffic controllers and pilots.

Effects of wingtip modifications on handling qualities of agricultural aircraft

NASA Technical Reports Server (NTRS)

Van Dam, C. P.

1981-01-01

The effect of wingtip modifications on the stability and control characteristics of an agricultural airplane has been studied by means of a nonplanar quasi-vortex-lattice method. The method is used to compute the changes in steady state and perturbed state lateral-directional stability and control derivatives produced by wingtip mounted winglets, vortex diffuser vanes, and tip extensions. The study shows that the combination of the excessive positive dihedral effect produced by the winglets and adverse yaw due to aileron deflection can have a detrimental effect on the roll control characteristics of the airplane. Introduction of an aileron-rudder-interconnect, and reduction of the effective dihedral by canting-in of the winglets, or addition of a lower winglet can eliminate the roll control problems.

Efficient Control Law Simulation for Multiple Mobile Robots

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

Driessen, B.J.; Feddema, J.T.; Kotulski, J.D.

1998-10-06

In this paper we consider the problem of simulating simple control laws involving large numbers of mobile robots. Such simulation can be computationally prohibitive if the number of robots is large enough, say 1 million, due to the 0(N2 ) cost of each time step. This work therefore uses hierarchical tree-based methods for calculating the control law. These tree-based approaches have O(NlogN) cost per time step, thus allowing for efficient simulation involving a large number of robots. For concreteness, a decentralized control law which involves only the distance and bearing to the closest neighbor robot will be considered. The timemore » to calculate the control law for each robot at each time step is demonstrated to be O(logN).« less

[Online gaming. Potential risk and prevention programs].

PubMed

Malischnig, Doris

2014-12-01

Online gaming is more and more common and increasingly accessible. Due to a lack of social control the participation could be a potential risk for certain customers. The given article focuses on prevention measures that are provided by the Austrian online gaming operator, the Austrian Lotteries, provider of the online gaming platform win2day, in the light of the specifics of Internet gaming in order to avoid problems with gaming.

Further Evidence for Nonspecificity of Theory of Mind in Preschoolers: Training and Transferability in the Understanding of False Beliefs and False Signs

ERIC Educational Resources Information Center

Iao, Lai-Sang; Leekam, Susan; Perner, Josef; McConachie, Helen

2011-01-01

In a training study, the authors addressed whether or not preschoolers' difficulty with false belief is due to a domain-specific problem with mental states. Following Slaughter's (1998) design, 57 children who failed a false-belief (FB) pretest received two sessions of training on either an FB, false sign (FS), or control task. All children were…

Generation of Aerodynamics Via Physics-Based Virtual Flight Simulations

DTIC Science & Technology

2008-12-01

problems associated with projectile and missile aerodynamics. For maneuvering munitions, the effect of many new weapon control mechanisms being...dynamic simulation. The terms containing YPAC constitute the Magnus air load acting at the Magnus center of pressure while the terms containing 0 2...an unsteady aerodynamic moment along with terms due to the fact that the center of pressure and center of Magnus are not located at the mass

Liquid propellant gas generators

NASA Technical Reports Server (NTRS)

1972-01-01

The design of gas generators intended to provide hot gases for turbine drive is discussed. Emphasis is placed on the design and operation of bipropellant gas generators because of their wider use. Problems and limitations involved in turbine operation due to temperature effects are analyzed. Methods of temperature control of gas turbines and combustion products are examined. Drawings of critical sections of gas turbines to show their operation and areas of stress are included.

Thrombophilia and Pregnancy Complications

PubMed Central

Simcox, Louise E.; Ormesher, Laura; Tower, Clare; Greer, Ian A.

2015-01-01

There is a paucity of strong evidence associated with adverse pregnancy outcomes and thrombophilia in pregnancy. These problems include both early (recurrent miscarriage) and late placental vascular-mediated problems (fetal loss, pre-eclampsia, placental abruption and intra-uterine growth restriction). Due to poor quality case-control and cohort study designs, there is often an increase in the relative risk of these complications associated with thrombophilia, particularly recurrent early pregnancy loss, late fetal loss and pre-eclampsia, but the absolute risk remains very small. It appears that low-molecular weight heparin has other benefits on the placental vascular system besides its anticoagulant properties. Its use is in the context of antiphospholipid syndrome and recurrent pregnancy loss and also in women with implantation failure to improve live birth rates. There is currently no role for low-molecular weight heparin to prevent late placental-mediated complications in patients with inherited thrombophilia and this may be due to small patient numbers in the studies involved in summarising the evidence. There is potential for low-molecular weight heparin to improve pregnancy outcomes in women with prior severe vascular complications of pregnancy such as early-onset intra-uterine growth restriction and pre-eclampsia but further high quality randomised controlled trials are required to answer this question. PMID:26633369

Bias due to differential participation in case-control studies and review of available approaches for adjustment.

PubMed

Aigner, Annette; Grittner, Ulrike; Becher, Heiko

2018-01-01

Low response rates in epidemiologic research potentially lead to the recruitment of a non-representative sample of controls in case-control studies. Problems in the unbiased estimation of odds ratios arise when characteristics causing the probability of participation are associated with exposure and outcome. This is a specific setting of selection bias and a realistic hazard in many case-control studies. This paper formally describes the problem and shows its potential extent, reviews existing approaches for bias adjustment applicable under certain conditions, compares and applies them. We focus on two scenarios: a characteristic C causing differential participation of controls is linked to the outcome through its association with risk factor E (scenario I), and C is additionally a genuine risk factor itself (scenario II). We further assume external data sources are available which provide an unbiased estimate of C in the underlying population. Given these scenarios, we (i) review available approaches and their performance in the setting of bias due to differential participation; (ii) describe two existing approaches to correct for the bias in both scenarios in more detail; (iii) present the magnitude of the resulting bias by simulation if the selection of a non-representative sample is ignored; and (iv) demonstrate the approaches' application via data from a case-control study on stroke. The bias of the effect measure for variable E in scenario I and C in scenario II can be large and should therefore be adjusted for in any analysis. It is positively associated with the difference in response rates between groups of the characteristic causing differential participation, and inversely associated with the total response rate in the controls. Adjustment in a standard logistic regression framework is possible in both scenarios if the population distribution of the characteristic causing differential participation is known or can be approximated well.

The Efficacy of Cognitive Behavioral Therapy: A Review of Meta-analyses

PubMed Central

Hofmann, Stefan G.; Asnaani, Anu; Vonk, Imke J.J.; Sawyer, Alice T.; Fang, Angela

2012-01-01

Cognitive behavioral therapy (CBT) refers to a popular therapeutic approach that has been applied to a variety of problems. The goal of this review was to provide a comprehensive survey of meta-analyses examining the efficacy of CBT. We identified 269 meta-analytic studies and reviewed of those a representative sample of 106 meta-analyses examining CBT for the following problems: substance use disorder, schizophrenia and other psychotic disorders, depression and dysthymia, bipolar disorder, anxiety disorders, somatoform disorders, eating disorders, insomnia, personality disorders, anger and aggression, criminal behaviors, general stress, distress due to general medical conditions, chronic pain and fatigue, distress related to pregnancy complications and female hormonal conditions. Additional meta-analytic reviews examined the efficacy of CBT for various problems in children and elderly adults. The strongest support exists for CBT of anxiety disorders, somatoform disorders, bulimia, anger control problems, and general stress. Eleven studies compared response rates between CBT and other treatments or control conditions. CBT showed higher response rates than the comparison conditions in 7 of these reviews and only one review reported that CBT had lower response rates than comparison treatments. In general, the evidence-base of CBT is very strong. However, additional research is needed to examine the efficacy of CBT for randomized-controlled studies. Moreover, except for children and elderly populations, no meta-analytic studies of CBT have been reported on specific subgroups, such as ethnic minorities and low income samples. PMID:23459093

Constrained model predictive control, state estimation and coordination

NASA Astrophysics Data System (ADS)

Yan, Jun

In this dissertation, we study the interaction between the control performance and the quality of the state estimation in a constrained Model Predictive Control (MPC) framework for systems with stochastic disturbances. This consists of three parts: (i) the development of a constrained MPC formulation that adapts to the quality of the state estimation via constraints; (ii) the application of such a control law in a multi-vehicle formation coordinated control problem in which each vehicle operates subject to a no-collision constraint posed by others' imperfect prediction computed from finite bit-rate, communicated data; (iii) the design of the predictors and the communication resource assignment problem that satisfy the performance requirement from Part (ii). Model Predictive Control (MPC) is of interest because it is one of the few control design methods which preserves standard design variables and yet handles constraints. MPC is normally posed as a full-state feedback control and is implemented in a certainty-equivalence fashion with best estimates of the states being used in place of the exact state. However, if the state constraints were handled in the same certainty-equivalence fashion, the resulting control law could drive the real state to violate the constraints frequently. Part (i) focuses on exploring the inclusion of state estimates into the constraints. It does this by applying constrained MPC to a system with stochastic disturbances. The stochastic nature of the problem requires re-posing the constraints in a probabilistic form. In Part (ii), we consider applying constrained MPC as a local control law in a coordinated control problem of a group of distributed autonomous systems. Interactions between the systems are captured via constraints. First, we inspect the application of constrained MPC to a completely deterministic case. Formation stability theorems are derived for the subsystems and conditions on the local constraint set are derived in order to guarantee local stability or convergence to a target state. If these conditions are met for all subsystems, then this stability is inherited by the overall system. For the case when each subsystem suffers from disturbances in the dynamics, own self-measurement noises, and quantization errors on neighbors' information due to the finite-bit-rate channels, the constrained MPC strategy developed in Part (i) is appropriate to apply. In Part (iii), we discuss the local predictor design and bandwidth assignment problem in a coordinated vehicle formation context. The MPC controller used in Part (ii) relates the formation control performance and the information quality in the way that large standoff implies conservative performance. We first develop an LMI (Linear Matrix Inequality) formulation for cross-estimator design in a simple two-vehicle scenario with non-standard information: one vehicle does not have access to the other's exact control value applied at each sampling time, but to its known, pre-computed, coupling linear feedback control law. Then a similar LMI problem is formulated for the bandwidth assignment problem that minimizes the total number of bits by adjusting the prediction gain matrices and the number of bits assigned to each variable. (Abstract shortened by UMI.)

Solvothermal method as a green chemistry solution for micro-encapsulation of phase change materials for high temperature thermal energy storage

NASA Astrophysics Data System (ADS)

Tudor, Albert Ioan; Motoc, Adrian Mihail; Ciobota, Cristina Florentina; Ciobota, Dan. Nastase; Piticescu, Radu Robert; Romero-Sanchez, Maria Dolores

2018-05-01

Thermal energy storage systems using phase change materials (PCMs) as latent heat storage are one of the main challenges at European level in improving the performances and efficiency of concentrated solar power energy generation due to their high energy density. PCM with high working temperatures in the temperature range 300-500 °C are required for these purposes. However their use is still limited due to the problems raised by the corrosion of the majority of high temperature PCMs and lower thermal transfer properties. Micro-encapsulation was proposed as one method to overcome these problems. Different micro-encapsulation methods proposed in the literature are presented and discussed. An original process for the micro-encapsulation of potassium nitrate as PCM in inorganic zinc oxide shells based on a solvothermal method followed by spray drying to produce microcapsules with controlled phase composition and distribution is proposed and their transformation temperatures and enthalpies measured by differential scanning calorimetry are presented.

Exposure to diesel and gasoline engine emissions and the risk of lung cancer.

PubMed

Parent, Marie-Elise; Rousseau, Marie-Claude; Boffetta, Paolo; Cohen, Aaron; Siemiatycki, Jack

2007-01-01

Pollution from motor vehicles constitutes a major environmental health problem. The present paper describes associations between diesel and gasoline engine emissions and lung cancer, as evidenced in a 1979-1985 population-based case-control study in Montreal, Canada. Cases were 857 male lung cancer patients. Controls were 533 population controls and 1,349 patients with other cancer types. Subjects were interviewed to obtain a detailed lifetime job history and relevant data on potential confounders. Industrial hygienists translated each job description into indices of exposure to several agents, including engine emissions. There was no evidence of excess risks of lung cancer with exposure to gasoline exhaust. For diesel engine emissions, results differed by control group. When cancer controls were considered, there was no excess risk. When population controls were studied, the odds ratios, after adjustments for potential confounders, were 1.2 (95% confidence interval: 0.8, 1.8) for any exposure and 1.6 (95% confidence interval: 0.9, 2.8) for substantial exposure. Confidence intervals between risk estimates derived from the two control groups overlapped considerably. These results provide some limited support for the hypothesis of an excess lung cancer risk due to diesel exhaust but no support for an increase in risk due to gasoline exhaust.

NASA's aviation safety research and technology program

NASA Technical Reports Server (NTRS)

Fichtl, G. H.

1977-01-01

Aviation safety is challenged by the practical necessity of compromising inherent factors of design, environment, and operation. If accidents are to be avoided these factors must be controlled to a degree not often required by other transport modes. The operational problems which challenge safety seem to occur most often in the interfaces within and between the design, the environment, and operations where mismatches occur due to ignorance or lack of sufficient understanding of these interactions. Under this report the following topics are summarized: (1) The nature of operating problems, (2) NASA aviation safety research, (3) clear air turbulence characterization and prediction, (4) CAT detection, (5) Measurement of Atmospheric Turbulence (MAT) Program, (6) Lightning, (7) Thunderstorm gust fronts, (8) Aircraft ground operating problems, (9) Aircraft fire technology, (10) Crashworthiness research, (11) Aircraft wake vortex hazard research, and (12) Aviation safety reporting system.

Classical and modern control strategies for the deployment, reconfiguration, and station-keeping of the National Aeronautics and Space Administration (NASA) Benchmark Tetrahedron Constellation

NASA Astrophysics Data System (ADS)

Capo-Lugo, Pedro A.

Formation flying consists of multiple spacecraft orbiting in a required configuration about a planet or through Space. The National Aeronautics and Space Administration (NASA) Benchmark Tetrahedron Constellation is one of the proposed constellations to be launched in the year 2009 and provides the motivation for this investigation. The problem that will be researched here consists of three stages. The first stage contains the deployment of the satellites; the second stage is the reconfiguration process to transfer the satellites through different specific sizes of the NASA benchmark problem; and, the third stage is the station-keeping procedure for the tetrahedron constellation. Every stage contains different control schemes and transfer procedures to obtain/maintain the proposed tetrahedron constellation. In the first stage, the deployment procedure will depend on a combination of two techniques in which impulsive maneuvers and a digital controller are used to deploy the satellites and to maintain the tetrahedron constellation at the following apogee point. The second stage that corresponds to the reconfiguration procedure shows a different control scheme in which the intelligent control systems are implemented to perform this procedure. In this research work, intelligent systems will eliminate the use of complex mathematical models and will reduce the computational time to perform different maneuvers. Finally, the station-keeping process, which is the third stage of this research problem, will be implemented with a two-level hierarchical control scheme to maintain the separation distance constraints of the NASA Benchmark Tetrahedron Constellation. For this station-keeping procedure, the system of equations defining the dynamics of a pair of satellites is transformed to take in account the perturbation due to the oblateness of the Earth and the disturbances due to solar pressure. The control procedures used in this research will be transformed from a continuous control system to a digital control system which will simplify the implementation into the computer onboard the satellite. In addition, this research will show an introductory chapter on attitude dynamics that can be used to maintain the orientation of the satellites, and an adaptive intelligent control scheme will be proposed to maintain the desired orientation of the spacecraft. In conclusion, a solution for the dynamics of the NASA Benchmark Tetrahedron Constellation will be presented in this research work. The main contribution of this work is the use of discrete control schemes, impulsive maneuvers, and intelligent control schemes that can be used to reduce the computational time in which these control schemes can be easily implemented in the computer onboard the satellite. These contributions are explained through the deployment, reconfiguration, and station-keeping process of the proposed NASA Benchmark Tetrahedron Constellation.

A Sarsa(λ)-Based Control Model for Real-Time Traffic Light Coordination

PubMed Central

Zhu, Fei; Liu, Quan; Fu, Yuchen; Huang, Wei

2014-01-01

Traffic problems often occur due to the traffic demands by the outnumbered vehicles on road. Maximizing traffic flow and minimizing the average waiting time are the goals of intelligent traffic control. Each junction wants to get larger traffic flow. During the course, junctions form a policy of coordination as well as constraints for adjacent junctions to maximize their own interests. A good traffic signal timing policy is helpful to solve the problem. However, as there are so many factors that can affect the traffic control model, it is difficult to find the optimal solution. The disability of traffic light controllers to learn from past experiences caused them to be unable to adaptively fit dynamic changes of traffic flow. Considering dynamic characteristics of the actual traffic environment, reinforcement learning algorithm based traffic control approach can be applied to get optimal scheduling policy. The proposed Sarsa(λ)-based real-time traffic control optimization model can maintain the traffic signal timing policy more effectively. The Sarsa(λ)-based model gains traffic cost of the vehicle, which considers delay time, the number of waiting vehicles, and the integrated saturation from its experiences to learn and determine the optimal actions. The experiment results show an inspiring improvement in traffic control, indicating the proposed model is capable of facilitating real-time dynamic traffic control. PMID:24592183

Interpreting large-scale experiments on effects of trawling on benthic fauna: an empirical test of the potential effects of spatial confounding in experiments without replicated control and trawled areas.

PubMed

Lindegarth; Valentinsson; Hansson; Ulmestrand

2000-03-15

Disturbances due to trawling and dredging is a serious threat to assemblages of benthic marine animals. We tested hypotheses about effects of trawling on benthic assemblages in a manipulative field experiment, using gear and intensities relevant to future management of trawling in a Swedish fjord. Three trawled and three control sites were sampled at several times before and after trawling was initiated. This paper describes how conclusions about effects of trawling might differ between experiments involving replicate sites and experiments using only one trawled and one control site, as in several recent studies. Analyses of selected taxa showed that abundances of many species changed differently among control sites. Differences in temporal change between pairs of single trawled and control sites were also frequent. Neither the quantitative nor the qualitative nature of differences between treatments could, however, be coherently interpreted among the different combinations of trawled and control sites. This is consistent with results obtained from analyses using all sites, which showed no consistent effects of trawling on any of these taxa. These results provide empirical evidence that spatial confounding may cause serious problems to formal interpretation of experiments, which use only one control and one trawled area. Such potential problems can best be solved by ensuring that the study incorporates more than one control site.

Limited variance control in statistical low thrust guidance analysis. [stochastic algorithm for SEP comet Encke flyby mission

NASA Technical Reports Server (NTRS)

Jacobson, R. A.

1975-01-01

Difficulties arise in guiding a solar electric propulsion spacecraft due to nongravitational accelerations caused by random fluctuations in the magnitude and direction of the thrust vector. These difficulties may be handled by using a low thrust guidance law based on the linear-quadratic-Gaussian problem of stochastic control theory with a minimum terminal miss performance criterion. Explicit constraints are imposed on the variances of the control parameters, and an algorithm based on the Hilbert space extension of a parameter optimization method is presented for calculation of gains in the guidance law. The terminal navigation of a 1980 flyby mission to the comet Encke is used as an example.

Real-Time Load-Side Control of Electric Power Systems

NASA Astrophysics Data System (ADS)

Zhao, Changhong

Two trends are emerging from modern electric power systems: the growth of renewable (e.g., solar and wind) generation, and the integration of information technologies and advanced power electronics. The former introduces large, rapid, and random fluctuations in power supply, demand, frequency, and voltage, which become a major challenge for real-time operation of power systems. The latter creates a tremendous number of controllable intelligent endpoints such as smart buildings and appliances, electric vehicles, energy storage devices, and power electronic devices that can sense, compute, communicate, and actuate. Most of these endpoints are distributed on the load side of power systems, in contrast to traditional control resources such as centralized bulk generators. This thesis focuses on controlling power systems in real time, using these load side resources. Specifically, it studies two problems. (1) Distributed load-side frequency control: We establish a mathematical framework to design distributed frequency control algorithms for flexible electric loads. In this framework, we formulate a category of optimization problems, called optimal load control (OLC), to incorporate the goals of frequency control, such as balancing power supply and demand, restoring frequency to its nominal value, restoring inter-area power flows, etc., in a way that minimizes total disutility for the loads to participate in frequency control by deviating from their nominal power usage. By exploiting distributed algorithms to solve OLC and analyzing convergence of these algorithms, we design distributed load-side controllers and prove stability of closed-loop power systems governed by these controllers. This general framework is adapted and applied to different types of power systems described by different models, or to achieve different levels of control goals under different operation scenarios. We first consider a dynamically coherent power system which can be equivalently modeled with a single synchronous machine. We then extend our framework to a multi-machine power network, where we consider primary and secondary frequency controls, linear and nonlinear power flow models, and the interactions between generator dynamics and load control. (2) Two-timescale voltage control: The voltage of a power distribution system must be maintained closely around its nominal value in real time, even in the presence of highly volatile power supply or demand. For this purpose, we jointly control two types of reactive power sources: a capacitor operating at a slow timescale, and a power electronic device, such as a smart inverter or a D-STATCOM, operating at a fast timescale. Their control actions are solved from optimal power flow problems at two timescales. Specifically, the slow-timescale problem is a chance-constrained optimization, which minimizes power loss and regulates the voltage at the current time instant while limiting the probability of future voltage violations due to stochastic changes in power supply or demand. This control framework forms the basis of an optimal sizing problem, which determines the installation capacities of the control devices by minimizing the sum of power loss and capital cost. We develop computationally efficient heuristics to solve the optimal sizing problem and implement real-time control. Numerical experiments show that the proposed sizing and control schemes significantly improve the reliability of voltage control with a moderate increase in cost.

Levey-Jennings Analysis Uncovers Unsuspected Causes of Immunohistochemistry Stain Variability.

PubMed

Vani, Kodela; Sompuram, Seshi R; Naber, Stephen P; Goldsmith, Jeffrey D; Fulton, Regan; Bogen, Steven A

Almost all clinical laboratory tests use objective, quantitative measures of quality control (QC), incorporating Levey-Jennings analysis and Westgard rules. Clinical immunohistochemistry (IHC) testing, in contrast, relies on subjective, qualitative QC review. The consequences of using Levey-Jennings analysis for QC assessment in clinical IHC testing are not known. To investigate this question, we conducted a 1- to 2-month pilot test wherein the QC for either human epidermal growth factor receptor 2 (HER-2) or progesterone receptor (PR) in 3 clinical IHC laboratories was quantified and analyzed with Levey-Jennings graphs. Moreover, conventional tissue controls were supplemented with a new QC comprised of HER-2 or PR peptide antigens coupled onto 8 μm glass beads. At institution 1, this more stringent analysis identified a decrease in the HER-2 tissue control that had escaped notice by subjective evaluation. The decrement was due to heterogeneity in the tissue control itself. At institution 2, we identified a 1-day sudden drop in the PR tissue control, also undetected by subjective evaluation, due to counterstain variability. At institution 3, a QC shift was identified, but only with 1 of 2 controls mounted on each slide. The QC shift was due to use of the instrument's selective reagent drop zones dispense feature. None of these events affected patient diagnoses. These case examples illustrate that subjective QC evaluation of tissue controls can detect gross assay failure but not subtle changes. The fact that QC issues arose from each site, and in only a pilot study, suggests that immunohistochemical stain variability may be an underappreciated problem.

Assessment of morbidity due to Schistosoma japonicum infection in China

PubMed Central

2014-01-01

This paper presents a historical assessment of morbidity due to the Schistosoma japonicum infection in China. Due to the socio-economic situation, which did not allow for a control program to be implemented until the early 1950s, morbidity was serious and mortality was high before this. Based on a few investigations and published papers, it can be said that the disease caused millions of deaths, and destroyed numerous families and villages. Since the 1950s, there has been a national control program, intensive control and prevention work has been carried out, and consequently the disease is being controlled. At present, both the prevalence and the morbidity of the disease have been decreasing substantially. The morbidity of the three phases of the disease is outlined in this paper. Comparatively higher morbidity is seen in the acute and advanced phases of the disease. The four major forms of advanced schistosomiasis i.e., ascites, megalosplenia, dwarfism, and colonic tumoroid proliferation, are outlined with their characteristic clinical presentations; their proportions are different during various periods of the national control program. Ectopic schistosomiasis and the relationship between the S. japonicum infection and colorectal cancer are also discussed. Post-transmission schistosomiasis is briefly discussed (which can happen even if the disease reaches the criteria of elimination, and the infection and transmission have stopped, but yet it still develops). The problem of mammalian reservoir hosts of S. japonicum makes the epidemiology and control of schistosomiasis in China even more complicated and arduous, and the control progress in animal reservoirs is briefly presented. PMID:24529186

Influence of beliefs about health and illness on self-care and care-seeking in foreign-born people with diabetic foot ulcers: dissimilarities related to origin.

PubMed

Hjelm, K; Apelqvist, J

2016-11-02

To describe beliefs about health and illness among foreign-born people with diabetic foot ulcers that might affect self-reported self-care and health-care seeking and to study whether there are dissimilarities related to origin. Qualitative descriptive study. Semi-structured interviews with people aged 38-86 years; 13 born in European and 13 in non-European countries (all except one in the Middle East). All resident in Sweden for 7-60 years (median: 18.5 years). Most believed foot ulcers were unavoidable and difficult to detect. Foot problems were mainly believed to be due to internal factors (diabetes), sometimes combined with external factors (inappropriate footwear, hot water, or barefoot walking). Health was described as freedom from illness and health professionals were seen as important sources of information. Perceived health deteriorated after the onset of the foot problems due to immobility and pain. People from the Middle East differed from other respondents as they discussed the importance of adapting to the will of Allah, leading to even poorer quality of life and a more negative view of future health. They also described more foot problems and perceived religion (Islam) with ritual washing of the feet to be important for health. However, they were regularly monitored to a lesser extent than European migrants. Economy affected health, more so in Europeans, due to expenses for medications and shoes. Many described limited activity in self-care, few had sought help for their problems and then solely among professionals, and had limited knowledge about the influence of glycaemic control on diabetes and foot status. Foreign-born people felt unable to prevent the incidence of foot ulcers, experienced problems with detection, and had limited knowledge of self-care. Dissimilarities in beliefs related to origin negatively influenced self-care of the feet, so it is important to assess individual beliefs and plan care and education accordingly.

Registratiom of TM data to digital elevation models

NASA Technical Reports Server (NTRS)

1984-01-01

Several problems arise when attempting to register LANDSAT thematic mapper data to U.S. B Geological Survey digital elevation models (DEMs). The TM data are currently available only in a rotated variant of the Space Oblique Mercator (SOM) map projection. Geometric transforms are thus; required to access TM data in the geodetic coordinates used by the DEMs. Due to positional errors in the TM data, these transforms require some sort of external control. The spatial resolution of TM data exceeds that of the most commonly DEM data. Oversampling DEM data to TM resolution introduces systematic noise. Common terrain processing algorithms (e.g., close computation) compound this problem by acting as high-pass filters.

[Problems of safety regulation under radioactive waste management in Russia].

PubMed

Monastyrskaia, S G; Kochetkov, O A; Barchukov, V G; Kuznetsova, L I

2012-01-01

Analysis of the requirements of Federal Law N 190 "About radioactive waste management and incorporation of changes into some legislative acts of the Russian Federation", as well as normative-legislative documents actual and planned to be published related to provision of radiation protection of the workers and the public have been done. Problems of safety regulation raised due to different approaches of Rospotrebnadzor, FMBA of Russia, Rostekhnadzor and Minprirody with respect to classification and categorization of the radioactive wastes, disposal, exemption from regulatory control, etc. have been discussed in the paper. Proposals regarding improvement of the system of safety regulation under radioactive waste management and of cooperation of various regulatory bodies have been formulated.

Optical systems engineering - A tutorial

NASA Technical Reports Server (NTRS)

Wyman, C. L.

1979-01-01

The paper examines the use of the systems engineering approach in the design of optical systems, noting that the use of such an approach which involves an integrated interdisciplinary approach to the development of systems is most appropriate for optics. It is shown that the high precision character of optics leads to complex and subtle effects on optical system performance, resulting from structural, thermal dynamical, control system, and manufacturing and assembly considerations. Attention is given to communication problems that often occur among users and optical engineers due to the unique factors of optical systems. It is concluded that it is essential that the optics community provide leadership to resolve communication problems and fully formalize the field of optical systems engineering.

Transition from Legacy to Connectivity Solution for Infrastructure Control of Smart Municipal Systems

NASA Astrophysics Data System (ADS)

Zabasta, A.; Kunicina, N.; Kondratjevs, K.

2017-06-01

Collaboration between heterogeneous systems and architectures is not an easy problem in the automation domain. By now, utilities and suppliers encounter real problems due to underestimated costs of technical solutions, frustration in selecting technical solutions relevant for local needs, and incompatibilities between a plenty of protocols and appropriate solutions. The paper presents research on creation of architecture of smart municipal systems in a local cloud of services that apply SOA and IoT approaches. The authors of the paper have developed a broker that applies orchestration services and resides on a gateway, which provides adapter and protocol translation functions, as well as applies a tool for wiring together hardware devices, APIs and online services.

Gene Kranz Visits Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

2006-01-01

On October 19, 2006, former NASA director of Mission Operations Gene Kranz was a keynote speaker at the Marshall Space Flight Center's (MSFC's) 2006 Annual Safety Day program. The best selling author of 'Failure Is Not An Option' and past Apollo flight director was featured during a morning session called 'Coffee and Kranz'. Marshall employees hung on his every word as he told the fascinating story of Apollo 13. Kranz was the acting flight director during the Apollo 13 mission, a mission that seemed doomed to fail due to an onboard explosion. Kranz and his flight control team worked around the clock relentlessly, solving problem after problem, until the crew was returned safely to Earth.

Around Marshall

NASA Image and Video Library

2006-10-19

On October 19, 2006, former NASA director of Mission Operations Gene Kranz was a keynote speaker at the Marshall Space Flight Center’s (MSFC’s) 2006 Annual Safety Day program. The best selling author of “Failure Is Not An Option” and past Apollo flight director was featured during a morning session called “Coffee and Kranz”. Marshall employees hung on his every word as he told the fascinating story of Apollo 13. Kranz was the acting flight director during the Apollo 13 mission, a mission that seemed doomed to fail due to an onboard explosion. Kranz and his flight control team worked around the clock relentlessly, solving problem after problem, until the crew was returned safely to Earth.

[Strategies to control vitamin A deficiency].

PubMed

Traoré, L; Banou, A A; Sacko, D; Malvy, D; Schémann, J F

1998-01-01

Vitamin A deficiency is a major public health problem in the countries of the Sahel. It causes xerophthalmia and high rates of child mortality and it occurs mostly in underdeveloped regions. People of all ages may suffer from vitamin A deficiency but it is a particular problem in pre-school-age children. Each year, about 250,000 children throughout the world become blind due to vitamin A deficiency. Measles, pneumonia and diarrhea reduce the child's reserves of retinol and increase the dietary requirement for vitamin A. Improvement of social conditions is a radical approach to preventing vitamin A deficiency. Three strategies are currently in use: horticultural activities and health education; fortification of food products; distribution of high-dose vitamin A capsules.

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

GTI

Manure management is an ever-increasing environmental impact problem within the U.S. livestock industry due to the trends in growing scale of operation of individual animal raising facilities. Anaerobic digestion, the fermentation of organic matter into a mixture of methane and carbon dioxide called biogas, offers the livestock industry a viable solution to this problem. When anaerobic digestion is combined with by-product recovery and biogas utilization, the integrated system can potentially solve manure handling issues while creating significant energy, environmental and economic opportunities. The overall objective of this project was to conduct a laboratory proof-of-concept evaluation to determine the potential energymore » generation and pathogen control benefits of applying anaerobic digestion for the management of swine manure.« less

Single machine scheduling with slack due dates assignment

NASA Astrophysics Data System (ADS)

Liu, Weiguo; Hu, Xiangpei; Wang, Xuyin

2017-04-01

This paper considers a single machine scheduling problem in which each job is assigned an individual due date based on a common flow allowance (i.e. all jobs have slack due date). The goal is to find a sequence for jobs, together with a due date assignment, that minimizes a non-regular criterion comprising the total weighted absolute lateness value and common flow allowance cost, where the weight is a position-dependent weight. In order to solve this problem, an ? time algorithm is proposed. Some extensions of the problem are also shown.

Inverse optimal self-tuning PID control design for an autonomous underwater vehicle

NASA Astrophysics Data System (ADS)

Rout, Raja; Subudhi, Bidyadhar

2017-01-01

This paper presents a new approach to path following control design for an autonomous underwater vehicle (AUV). A NARMAX model of the AUV is derived first and then its parameters are adapted online using the recursive extended least square algorithm. An adaptive Propotional-Integral-Derivative (PID) controller is developed using the derived parameters to accomplish the path following task of an AUV. The gain parameters of the PID controller are tuned using an inverse optimal control technique, which alleviates the problem of solving Hamilton-Jacobian equation and also satisfies an error cost function. Simulation studies were pursued to verify the efficacy of the proposed control algorithm. From the obtained results, it is envisaged that the proposed NARMAX model-based self-tuning adaptive PID control provides good path following performance even in the presence of uncertainty arising due to ocean current or hydrodynamic parameter.

Decorticate posture

MedlinePlus

Abnormal posturing - decorticate posture; Traumatic brain injury - decorticate posture ... Brain problem due to drugs, poisoning, or infection Traumatic brain injury Brain problem due to liver failure Increased pressure ...

Active model-based balancing strategy for self-reconfigurable batteries

NASA Astrophysics Data System (ADS)

Bouchhima, Nejmeddine; Schnierle, Marc; Schulte, Sascha; Birke, Kai Peter

2016-08-01

This paper describes a novel balancing strategy for self-reconfigurable batteries where the discharge and charge rates of each cell can be controlled. While much effort has been focused on improving the hardware architecture of self-reconfigurable batteries, energy equalization algorithms have not been systematically optimized in terms of maximizing the efficiency of the balancing system. Our approach includes aspects of such optimization theory. We develop a balancing strategy for optimal control of the discharge rate of battery cells. We first formulate the cell balancing as a nonlinear optimal control problem, which is modeled afterward as a network program. Using dynamic programming techniques and MATLAB's vectorization feature, we solve the optimal control problem by generating the optimal battery operation policy for a given drive cycle. The simulation results show that the proposed strategy efficiently balances the cells over the life of the battery, an obvious advantage that is absent in the other conventional approaches. Our algorithm is shown to be robust when tested against different influencing parameters varying over wide spectrum on different drive cycles. Furthermore, due to the little computation time and the proved low sensitivity to the inaccurate power predictions, our strategy can be integrated in a real-time system.

Adjoint-Baed Optimal Control on the Pitch Angle of a Single-Bladed Vertical-Axis Wind Turbine

NASA Astrophysics Data System (ADS)

Tsai, Hsieh-Chen; Colonius, Tim

2017-11-01

Optimal control on the pitch angle of a NACA0018 single-bladed vertical-axis wind turbine (VAWT) is numerically investigated at a low Reynolds number of 1500. With fixed tip-speed ratio, the input power is minimized and mean tangential force is maximized over a specific time horizon. The immersed boundary method is used to simulate the two-dimensional, incompressible flow around a horizontal cross section of the VAWT. The problem is formulated as a PDE constrained optimization problem and an iterative solution is obtained using adjoint-based conjugate gradient methods. By the end of the longest control horizon examined, two controls end up with time-invariant pitch angles of about the same magnitude but with the opposite signs. The results show that both cases lead to a reduction in the input power but not necessarily an enhancement in the mean tangential force. These reductions in input power are due to the removal of a power-damaging phenomenon that occurs when a vortex pair is captured by the blade in the upwind-half region of a cycle. This project was supported by Caltech FLOWE center/Gordon and Betty Moore Foundation.

A randomised controlled trial of empowerment training for Chinese abused pregnant women in Hong Kong.

PubMed

Tiwari, A; Leung, W C; Leung, T W; Humphreys, J; Parker, B; Ho, P C

2005-09-01

To evaluate the effectiveness of an empowerment intervention in reducing intimate partner violence (IPV) and improving health status. Randomised controlled trial. Antenatal clinic in a public hospital in Hong Kong. One hundred and ten Chinese pregnant women with a history of abuse by their intimate partners. Women were randomised to the experimental or control group. Experimental group women received empowerment training specially designed for Chinese abused pregnant women while the control group women received standard care for abused women. Data were collected at study entry and six weeks postnatal. IPV [on the Conflict Tactics Scale (CTS)], health-related quality of life (SF-36) and postnatal depression [Edinburgh Postnatal Depression Scale (EPDS)]. Following the training, the experimental group had significantly higher physical functioning and had significantly improved role limitation due to physical problems and emotional problems. They also reported less psychological (but not sexual) abuse, minor (but not severe) physical violence and had significantly lower postnatal depression scores. However, they reported more bodily pain. An empowerment intervention specially designed for Chinese abused pregnant women was effective in reducing IPV and improving the health status of the women.

The control algorithm of the system ‘frequency converter - asynchronous motor’ of the batcher

NASA Astrophysics Data System (ADS)

Lyapushkin, S. V.; Martyushev, N. V.; Shiryaev, S. Y.

2017-01-01

The paper is devoted to the solution of the problem of optimum batching of bulk mixtures according to the criterion of accuracy and maximally possible performance. This problem is solved for applied utilization when running the system ‘frequency converter - asynchronous motor’ having pulse-width modulation of a screw batcher of agricultural equipment. The developed control algorithm allows batching small components of a bulk mixture with the prescribed accuracy due to the weight consideration of the falling column of the material being in the air after the screw stoppage. The paper also shows that in order to reduce the influence of the mass of the ‘falling column’ on the accuracy of batching, it is necessary to specify the sequence of batching of components inside of the recipe beginning from the largest component ending with the least one. To exclude the variable error of batching, which arises owing to the mass of the material column, falling into the batcher-bunker, the algorithm of dynamic correction of the task is used in the control system.

Orbital Disturbance Analysis due to the Lunar Gravitational Potential and Deviation Minimization through the Trajectory Control in Closed Loop

NASA Astrophysics Data System (ADS)

Gonçalves, L. D.; Rocco, E. M.; de Moraes, R. V.

2013-10-01

A study evaluating the influence due to the lunar gravitational potential, modeled by spherical harmonics, on the gravity acceleration is accomplished according to the model presented in Konopliv (2001). This model provides the components x, y and z for the gravity acceleration at each moment of time along the artificial satellite orbit and it enables to consider the spherical harmonic degree and order up to100. Through a comparison between the gravity acceleration from a central field and the gravity acceleration provided by Konopliv's model, it is obtained the disturbing velocity increment applied to the vehicle. Then, through the inverse problem, the Keplerian elements of perturbed orbit of the satellite are calculated allowing the orbital motion analysis. Transfer maneuvers and orbital correction of lunar satellites are simulated considering the disturbance due to non-uniform gravitational potential of the Moon, utilizing continuous thrust and trajectory control in closed loop. The simulations are performed using the Spacecraft Trajectory Simulator-STRS, Rocco (2008), which evaluate the behavior of the orbital elements, fuel consumption and thrust applied to the satellite over the time.

Controlling state explosion during automatic verification of delay-insensitive and delay-constrained VLSI systems using the POM verifier

NASA Technical Reports Server (NTRS)

Probst, D.; Jensen, L.

1991-01-01

Delay-insensitive VLSI systems have a certain appeal on the ground due to difficulties with clocks; they are even more attractive in space. We answer the question, is it possible to control state explosion arising from various sources during automatic verification (model checking) of delay-insensitive systems? State explosion due to concurrency is handled by introducing a partial-order representation for systems, and defining system correctness as a simple relation between two partial orders on the same set of system events (a graph problem). State explosion due to nondeterminism (chiefly arbitration) is handled when the system to be verified has a clean, finite recurrence structure. Backwards branching is a further optimization. The heart of this approach is the ability, during model checking, to discover a compact finite presentation of the verified system without prior composition of system components. The fully-implemented POM verification system has polynomial space and time performance on traditional asynchronous-circuit benchmarks that are exponential in space and time for other verification systems. We also sketch the generalization of this approach to handle delay-constrained VLSI systems.

The expectancy-value muddle in the theory of planned behaviour - and some proposed solutions.

PubMed

French, David P; Hankins, Matthew

2003-02-01

The authors of the Theories of Reasoned Action and Planned Behaviour recommended a method for statistically analysing the relationships between beliefs and the Attitude, Subjective Norm, and Perceived Behavioural Control constructs. This method has been used in the overwhelming majority of studies using these theories. However, there is a growing awareness that this method yields statistically uninterpretable results (Evans, 1991). Despite this, the use of this method is continuing, as is uninformed interpretation of this problematic research literature. This is probably due to the lack of a simple account of where the problem lies, and the large number of alternatives available. This paper therefore summarizes the problem as simply as possible, gives consideration to the conclusions that can be validly drawn from studies that contain this problem, and critically reviews the many alternatives that have been proposed to address this problem. Different techniques are identified as being suitable, according to the purpose of the specific research project.

Investigation and appreciation of optimal output feedback. Volume 1: A convergent algorithm for the stochastic infinite-time discrete optimal output feedback problem

NASA Technical Reports Server (NTRS)

Halyo, N.; Broussard, J. R.

1984-01-01

The stochastic, infinite time, discrete output feedback problem for time invariant linear systems is examined. Two sets of sufficient conditions for the existence of a stable, globally optimal solution are presented. An expression for the total change in the cost function due to a change in the feedback gain is obtained. This expression is used to show that a sequence of gains can be obtained by an algorithm, so that the corresponding cost sequence is monotonically decreasing and the corresponding sequence of the cost gradient converges to zero. The algorithm is guaranteed to obtain a critical point of the cost function. The computational steps necessary to implement the algorithm on a computer are presented. The results are applied to a digital outer loop flight control problem. The numerical results for this 13th order problem indicate a rate of convergence considerably faster than two other algorithms used for comparison.

Optimization of Airport Surface Traffic: A Case-Study of Incheon International Airport

NASA Technical Reports Server (NTRS)

Eun, Yeonju; Jeon, Daekeun; Lee, Hanbong; Jung, Yoon C.; Zhu, Zhifan; Jeong, Myeongsook; Kim, Hyounkong; Oh, Eunmi; Hong, Sungkwon

2017-01-01

This study aims to develop a controllers decision support tool for departure and surface management of ICN. Airport surface traffic optimization for Incheon International Airport (ICN) in South Korea was studied based on the operational characteristics of ICN and airspace of Korea. For surface traffic optimization, a multiple runway scheduling problem and a taxi scheduling problem were formulated into two Mixed Integer Linear Programming (MILP) optimization models. The Miles-In-Trail (MIT) separation constraint at the departure fix shared by the departure flights from multiple runways and the runway crossing constraints due to the taxi route configuration specific to ICN were incorporated into the runway scheduling and taxiway scheduling problems, respectively. Since the MILP-based optimization model for the multiple runway scheduling problem may be computationally intensive, computation times and delay costs of different solving methods were compared for a practical implementation. This research was a collaboration between Korea Aerospace Research Institute (KARI) and National Aeronautics and Space Administration (NASA).

Optimization of Airport Surface Traffic: A Case-Study of Incheon International Airport

NASA Technical Reports Server (NTRS)

Eun, Yeonju; Jeon, Daekeun; Lee, Hanbong; Jung, Yoon Chul; Zhu, Zhifan; Jeong, Myeong-Sook; Kim, Hyoun Kyoung; Oh, Eunmi; Hong, Sungkwon

2017-01-01

This study aims to develop a controllers' decision support tool for departure and surface management of ICN. Airport surface traffic optimization for Incheon International Airport (ICN) in South Korea was studied based on the operational characteristics of ICN and airspace of Korea. For surface traffic optimization, a multiple runway scheduling problem and a taxi scheduling problem were formulated into two Mixed Integer Linear Programming (MILP) optimization models. The Miles-In-Trail (MIT) separation constraint at the departure fix shared by the departure flights from multiple runways and the runway crossing constraints due to the taxi route configuration specific to ICN were incorporated into the runway scheduling and taxiway scheduling problems, respectively. Since the MILP-based optimization model for the multiple runway scheduling problem may be computationally intensive, computation times and delay costs of different solving methods were compared for a practical implementation. This research was a collaboration between Korea Aerospace Research Institute (KARI) and National Aeronautics and Space Administration (NASA).

Theoretical study of network design methodologies for the aerial relay system. [energy consumption and air traffic control

NASA Technical Reports Server (NTRS)

Rivera, J. M.; Simpson, R. W.

1980-01-01

The aerial relay system network design problem is discussed. A generalized branch and bound based algorithm is developed which can consider a variety of optimization criteria, such as minimum passenger travel time and minimum liner and feeder operating costs. The algorithm, although efficient, is basically useful for small size networks, due to its nature of exponentially increasing computation time with the number of variables.

Mathematical Modeling of Physical and Cognitive Performance Decrement from Mechanical and Inhalation Insults

DTIC Science & Technology

2006-12-01

on specific short term problems. 1.1.1 Dynamic Physiological Modeling The oxygenation of the blood by the lung through respiration is a critical...tests as apnea , reduced arterial saturation, and may even be linked to long term CNS deficits. Inhalation of toxic gases can dramatically affect the...of TGAS model the respiration , circulation, and metabolic processes and include models of the ventilation and cardiac output control due to 3

Long-term follow-up of mental health, health-related quality of life and associations with motor skills in young adults born preterm with very low birth weight.

PubMed

Husby, Ingrid Marie; Stray, Kaia Mølbach-Thellefsen; Olsen, Alexander; Lydersen, Stian; Indredavik, Marit Sæbø; Brubakk, Ann-Mari; Skranes, Jon; Evensen, Kari Anne I

2016-04-07

Being born with very low birth weight (VLBW: ≤ 1,500 g) is related to long-term disability and neurodevelopmental problems, possibly affecting mental health and health-related quality of life (HRQoL). However, studies in young adulthood yield mixed findings. The aim of this study was to examine mental health and HRQoL at 23 years, including changes from 20 to 23 years and associations with motor skills in VLBW young adults compared with controls. In a geographically based follow-up study, 35 VLBW and 37 term-born young adults were assessed at 23 years by using Achenbach Adult Self-Report (ASR), Short Form 36 Health Survey (SF-36), Beck Depression Inventory (BDI) and various motor tests. The ASR and SF-36 were also used at 20 years. Longitudinal changes in ASR and SF-36 from 20 to 23 years were analysed by linear mixed models and associations with motor skills at 23 years by linear regression. At 23 years, total ASR score was 38.6 (SD: 21.7) in the VLBW group compared with 29.0 (SD: 18.6) in the control group (p = 0.048). VLBW participants had higher scores for attention problems, internalizing problems and critical items, and they reported to drink less alcohol than controls. BDI total score did not differ between groups. On SF-36, VLBW participants reported significantly poorer physical and social functioning, more role-limitations due to physical and emotional problems, more bodily pain and lower physical and mental component summaries than controls. In the VLBW group, total ASR score increased by 9.0 (95 % CI: 3.3 to 14.7) points from 20 to 23 years (p = 0.009 vs controls), physical and mental component summaries of SF-36 decreased by 2.9 (95 % CI: -4.8 to -1.1) and 4.4 (95 % CI: -7.1 to -1.7) points, respectively (p = 0.012 and p = 0.022 vs controls). Among VLBW participants, more mental health problems and lower physical and mental HRQoL were associated with poorer motor skills at 23 years. VLBW young adults reported poorer and declining mental health and HRQoL in the transitional phase into adulthood. They seemed to have a cautious lifestyle with more internalizing problems and less alcohol use. The associations of mental health problems and HRQoL with motor skills are likely to reflect a shared aetiology.

An optimal control method for fluid structure interaction systems via adjoint boundary pressure

NASA Astrophysics Data System (ADS)

Chirco, L.; Da Vià, R.; Manservisi, S.

2017-11-01

In recent year, in spite of the computational complexity, Fluid-structure interaction (FSI) problems have been widely studied due to their applicability in science and engineering. Fluid-structure interaction systems consist of one or more solid structures that deform by interacting with a surrounding fluid flow. FSI simulations evaluate the tensional state of the mechanical component and take into account the effects of the solid deformations on the motion of the interior fluids. The inverse FSI problem can be described as the achievement of a certain objective by changing some design parameters such as forces, boundary conditions and geometrical domain shapes. In this paper we would like to study the inverse FSI problem by using an optimal control approach. In particular we propose a pressure boundary optimal control method based on Lagrangian multipliers and adjoint variables. The objective is the minimization of a solid domain displacement matching functional obtained by finding the optimal pressure on the inlet boundary. The optimality system is derived from the first order necessary conditions by taking the Fréchet derivatives of the Lagrangian with respect to all the variables involved. The optimal solution is then obtained through a standard steepest descent algorithm applied to the optimality system. The approach presented in this work is general and could be used to assess other objective functionals and controls. In order to support the proposed approach we perform a few numerical tests where the fluid pressure on the domain inlet controls the displacement that occurs in a well defined region of the solid domain.

Reentry trajectory optimization with waypoint and no-fly zone constraints using multiphase convex programming

NASA Astrophysics Data System (ADS)

Zhao, Dang-Jun; Song, Zheng-Yu

2017-08-01

This study proposes a multiphase convex programming approach for rapid reentry trajectory generation that satisfies path, waypoint and no-fly zone (NFZ) constraints on Common Aerial Vehicles (CAVs). Because the time when the vehicle reaches the waypoint is unknown, the trajectory of the vehicle is divided into several phases according to the prescribed waypoints, rendering a multiphase optimization problem with free final time. Due to the requirement of rapidity, the minimum flight time of each phase index is preferred over other indices in this research. The sequential linearization is used to approximate the nonlinear dynamics of the vehicle as well as the nonlinear concave path constraints on the heat rate, dynamic pressure, and normal load; meanwhile, the convexification techniques are proposed to relax the concave constraints on control variables. Next, the original multiphase optimization problem is reformulated as a standard second-order convex programming problem. Theoretical analysis is conducted to show that the original problem and the converted problem have the same solution. Numerical results are presented to demonstrate that the proposed approach is efficient and effective.

Reproductive health problems loom in LDCs.

PubMed

1995-01-01

According to reports from the Program for Appropriate Technology in Health (PATH) and the World Bank, women in less developed countries (LDCs) suffer the greatest risk due to reproductive health problems. At any given time, a woman in a LDC is more likely than not to have at least 1 reproductive health problem that could be treated by a primary care provider or counseling and referral ("Women's Reproductive Health: The Role of Family Planning Programs," a PATH report). Among diseases for which cost-effective interventions exist (treatments or preventive measures), reproductive health problems account for the majority of the disease burden (a measure of healthy years lost due to disability or premature death) among women aged 15-44. A study of 650 women in India found that more than 50% reported specific gynecological problems; clinical examination found more than 90% had 1 or more such problems. In a study of 509 nonpregnant women in rural Egypt, it was discovered that more than 52% had a reproductive tract infection, 56% had some form of uterine prolapse, 14% had a urinary tract infection, and 11% had an abnormal Pap smear. Major reproductive health problems continue into menopause; cervical cancer, which is linked to reproductive tract infections and early and frequent childbearing, strikes 400,000 women in LDCs each year. Sexually transmitted disease (STD) and human immunodeficiency virus (HIV) infections are also problems; women are twice as likely as men to contact gonorrhea from an infected sex partner, and 14 million women will have been infected with HIV by the year 2000 (WHO estimate). Treatment is often unsought by women because they do not understand the risk, are unaware of the symptoms, or fear the stigma of attending a clinic. If all the women who wanted to control their fertility had access to family planning services, maternal mortality would decrease by nearly 50%. Reproductive health services (routine gynecological care, perinatal care, family planning services, cancer screening, STD/HIV services, nutritional supplementation, and other services appropriate to age) are needed.

Selection bias in population-based cancer case-control studies due to incomplete sampling frame coverage.

PubMed

Walsh, Matthew C; Trentham-Dietz, Amy; Gangnon, Ronald E; Nieto, F Javier; Newcomb, Polly A; Palta, Mari

2012-06-01

Increasing numbers of individuals are choosing to opt out of population-based sampling frames due to privacy concerns. This is especially a problem in the selection of controls for case-control studies, as the cases often arise from relatively complete population-based registries, whereas control selection requires a sampling frame. If opt out is also related to risk factors, bias can arise. We linked breast cancer cases who reported having a valid driver's license from the 2004-2008 Wisconsin women's health study (N = 2,988) with a master list of licensed drivers from the Wisconsin Department of Transportation (WDOT). This master list excludes Wisconsin drivers that requested their information not be sold by the state. Multivariate-adjusted selection probability ratios (SPR) were calculated to estimate potential bias when using this driver's license sampling frame to select controls. A total of 962 cases (32%) had opted out of the WDOT sampling frame. Cases age <40 (SPR = 0.90), income either unreported (SPR = 0.89) or greater than $50,000 (SPR = 0.94), lower parity (SPR = 0.96 per one-child decrease), and hormone use (SPR = 0.93) were significantly less likely to be covered by the WDOT sampling frame (α = 0.05 level). Our results indicate the potential for selection bias due to differential opt out between various demographic and behavioral subgroups of controls. As selection bias may differ by exposure and study base, the assessment of potential bias needs to be ongoing. SPRs can be used to predict the direction of bias when cases and controls stem from different sampling frames in population-based case-control studies.

Hybrid Metaheuristics for Solving a Fuzzy Single Batch-Processing Machine Scheduling Problem

PubMed Central

Molla-Alizadeh-Zavardehi, S.; Tavakkoli-Moghaddam, R.; Lotfi, F. Hosseinzadeh

2014-01-01

This paper deals with a problem of minimizing total weighted tardiness of jobs in a real-world single batch-processing machine (SBPM) scheduling in the presence of fuzzy due date. In this paper, first a fuzzy mixed integer linear programming model is developed. Then, due to the complexity of the problem, which is NP-hard, we design two hybrid metaheuristics called GA-VNS and VNS-SA applying the advantages of genetic algorithm (GA), variable neighborhood search (VNS), and simulated annealing (SA) frameworks. Besides, we propose three fuzzy earliest due date heuristics to solve the given problem. Through computational experiments with several random test problems, a robust calibration is applied on the parameters. Finally, computational results on different-scale test problems are presented to compare the proposed algorithms. PMID:24883359

Single Machine Scheduling and Due Date Assignment with Past-Sequence-Dependent Setup Time and Position-Dependent Processing Time

PubMed Central

Zhao, Chuan-Li; Hsu, Hua-Feng

2014-01-01

This paper considers single machine scheduling and due date assignment with setup time. The setup time is proportional to the length of the already processed jobs; that is, the setup time is past-sequence-dependent (p-s-d). It is assumed that a job's processing time depends on its position in a sequence. The objective functions include total earliness, the weighted number of tardy jobs, and the cost of due date assignment. We analyze these problems with two different due date assignment methods. We first consider the model with job-dependent position effects. For each case, by converting the problem to a series of assignment problems, we proved that the problems can be solved in O(n 4) time. For the model with job-independent position effects, we proved that the problems can be solved in O(n 3) time by providing a dynamic programming algorithm. PMID:25258727

Single machine scheduling and due date assignment with past-sequence-dependent setup time and position-dependent processing time.

PubMed

Zhao, Chuan-Li; Hsu, Chou-Jung; Hsu, Hua-Feng

2014-01-01

This paper considers single machine scheduling and due date assignment with setup time. The setup time is proportional to the length of the already processed jobs; that is, the setup time is past-sequence-dependent (p-s-d). It is assumed that a job's processing time depends on its position in a sequence. The objective functions include total earliness, the weighted number of tardy jobs, and the cost of due date assignment. We analyze these problems with two different due date assignment methods. We first consider the model with job-dependent position effects. For each case, by converting the problem to a series of assignment problems, we proved that the problems can be solved in O(n(4)) time. For the model with job-independent position effects, we proved that the problems can be solved in O(n(3)) time by providing a dynamic programming algorithm.

Targeting a global health problem: Vaccine design and challenges for the control of tick-borne diseases.

PubMed

de la Fuente, José; Contreras, Marinela; Estrada-Peña, Agustín; Cabezas-Cruz, Alejandro

2017-09-12

It has been over twenty years since the first vaccines for the control of tick infestations became commercially available. These vaccines proved their efficacy and the potential of this approach for the control of tick-borne diseases (TBDs), which represent a growing burden for human and animal health worldwide. In all these years, research in this area has produced new tick-derived and pathogen-derived candidate protective antigens. However, the potential of vaccines for the control of TBDs has been underestimated due to major challenges to reduce tick infestations, pathogen infection, multiplication and transmission, tick attachment and feeding time and/or host pathogen infection. Nevertheless, vaccines constitute the most safe and effective intervention for the control of TBDs in humans, domestic and wild animals. Copyright © 2017 Elsevier Ltd. All rights reserved.

Structured Kernel Subspace Learning for Autonomous Robot Navigation.

PubMed

Kim, Eunwoo; Choi, Sungjoon; Oh, Songhwai

2018-02-14

This paper considers two important problems for autonomous robot navigation in a dynamic environment, where the goal is to predict pedestrian motion and control a robot with the prediction for safe navigation. While there are several methods for predicting the motion of a pedestrian and controlling a robot to avoid incoming pedestrians, it is still difficult to safely navigate in a dynamic environment due to challenges, such as the varying quality and complexity of training data with unwanted noises. This paper addresses these challenges simultaneously by proposing a robust kernel subspace learning algorithm based on the recent advances in nuclear-norm and l 1 -norm minimization. We model the motion of a pedestrian and the robot controller using Gaussian processes. The proposed method efficiently approximates a kernel matrix used in Gaussian process regression by learning low-rank structured matrix (with symmetric positive semi-definiteness) to find an orthogonal basis, which eliminates the effects of erroneous and inconsistent data. Based on structured kernel subspace learning, we propose a robust motion model and motion controller for safe navigation in dynamic environments. We evaluate the proposed robust kernel learning in various tasks, including regression, motion prediction, and motion control problems, and demonstrate that the proposed learning-based systems are robust against outliers and outperform existing regression and navigation methods.

Unification theory of optimal life histories and linear demographic models in internal stochasticity.

PubMed

Oizumi, Ryo

2014-01-01

Life history of organisms is exposed to uncertainty generated by internal and external stochasticities. Internal stochasticity is generated by the randomness in each individual life history, such as randomness in food intake, genetic character and size growth rate, whereas external stochasticity is due to the environment. For instance, it is known that the external stochasticity tends to affect population growth rate negatively. It has been shown in a recent theoretical study using path-integral formulation in structured linear demographic models that internal stochasticity can affect population growth rate positively or negatively. However, internal stochasticity has not been the main subject of researches. Taking account of effect of internal stochasticity on the population growth rate, the fittest organism has the optimal control of life history affected by the stochasticity in the habitat. The study of this control is known as the optimal life schedule problems. In order to analyze the optimal control under internal stochasticity, we need to make use of "Stochastic Control Theory" in the optimal life schedule problem. There is, however, no such kind of theory unifying optimal life history and internal stochasticity. This study focuses on an extension of optimal life schedule problems to unify control theory of internal stochasticity into linear demographic models. First, we show the relationship between the general age-states linear demographic models and the stochastic control theory via several mathematical formulations, such as path-integral, integral equation, and transition matrix. Secondly, we apply our theory to a two-resource utilization model for two different breeding systems: semelparity and iteroparity. Finally, we show that the diversity of resources is important for species in a case. Our study shows that this unification theory can address risk hedges of life history in general age-states linear demographic models.

Unification Theory of Optimal Life Histories and Linear Demographic Models in Internal Stochasticity

PubMed Central

Oizumi, Ryo

2014-01-01

Life history of organisms is exposed to uncertainty generated by internal and external stochasticities. Internal stochasticity is generated by the randomness in each individual life history, such as randomness in food intake, genetic character and size growth rate, whereas external stochasticity is due to the environment. For instance, it is known that the external stochasticity tends to affect population growth rate negatively. It has been shown in a recent theoretical study using path-integral formulation in structured linear demographic models that internal stochasticity can affect population growth rate positively or negatively. However, internal stochasticity has not been the main subject of researches. Taking account of effect of internal stochasticity on the population growth rate, the fittest organism has the optimal control of life history affected by the stochasticity in the habitat. The study of this control is known as the optimal life schedule problems. In order to analyze the optimal control under internal stochasticity, we need to make use of “Stochastic Control Theory” in the optimal life schedule problem. There is, however, no such kind of theory unifying optimal life history and internal stochasticity. This study focuses on an extension of optimal life schedule problems to unify control theory of internal stochasticity into linear demographic models. First, we show the relationship between the general age-states linear demographic models and the stochastic control theory via several mathematical formulations, such as path–integral, integral equation, and transition matrix. Secondly, we apply our theory to a two-resource utilization model for two different breeding systems: semelparity and iteroparity. Finally, we show that the diversity of resources is important for species in a case. Our study shows that this unification theory can address risk hedges of life history in general age-states linear demographic models. PMID:24945258

Long-Term Quality of Life in Adult Survivors of Pediatric Differentiated Thyroid Carcinoma.

PubMed

Nies, Marloes; Klein Hesselink, Mariëlle S; Huizinga, Gea A; Sulkers, Esther; Brouwers, Adrienne H; Burgerhof, Johannes G M; van Dam, Eveline W C M; Havekes, Bas; van den Heuvel-Eibrink, Marry M; Corssmit, Eleonora P M; Kremer, Leontien C M; Netea-Maier, Romana T; van der Pal, Heleen J H; Peeters, Robin P; Plukker, John T M; Ronckers, Cécile M; van Santen, Hanneke M; Tissing, Wim J E; Links, Thera P; Bocca, Gianni

2017-04-01

Little is known about long-term quality of life (QoL) of survivors of pediatric differentiated thyroid carcinoma. Therefore, this study aimed to evaluate generic health-related QoL (HRQoL), fatigue, anxiety, and depression in these survivors compared with matched controls, and to evaluate thyroid cancer-specific HRQoL in survivors only. Survivors diagnosed between 1970 and 2013 at age ≤18 years, were included. Exclusion criteria were a follow-up <5 years, attained age <18 years, or diagnosis of DTC as a second malignant neoplasm (SMN). Controls were matched by age, sex, and socioeconomic status. Survivors and controls were asked to complete 3 questionnaires [Short-Form 36 (HRQoL), Multidimensional Fatigue Inventory 20 (fatigue), and Hospital Anxiety and Depression Scale (anxiety/depression)]. Survivors completed a thyroid cancer-specific HRQoL questionnaire. Sixty-seven survivors and 56 controls. Median age of survivors at evaluation was 34.2 years (range, 18.8 to 61.7). Median follow-up was 17.8 years (range, 5.0 to 44.7). On most QoL subscales, scores of survivors and controls did not differ significantly. However, survivors had more physical problems (P = 0.031), role limitations due to physical problems (P = 0.021), and mental fatigue (P = 0.016) than controls. Some thyroid cancer-specific complaints (e.g., sensory complaints and chilliness) were present in survivors. Unemployment and more extensive disease or treatment characteristics were most frequently associated with worse QoL. Overall, long-term QoL in survivors of pediatric DTC was normal. Survivors experienced mild impairment of QoL in some domains (physical problems, mental fatigue, and various thyroid cancer-specific complaints). Factors possibly affecting QoL need further exploration. Copyright © 2017 Endocrine Society

Application of simple adaptive control to water hydraulic servo cylinder system

NASA Astrophysics Data System (ADS)

Ito, Kazuhisa; Yamada, Tsuyoshi; Ikeo, Shigeru; Takahashi, Koji

2012-09-01

Although conventional model reference adaptive control (MRAC) achieves good tracking performance for cylinder control, the controller structure is much more complicated and has less robustness to disturbance in real applications. This paper discusses the use of simple adaptive control (SAC) for positioning a water hydraulic servo cylinder system. Compared with MRAC, SAC has a simpler and lower order structure, i.e., higher feasibility. The control performance of SAC is examined and evaluated on a water hydraulic servo cylinder system. With the recent increased concerns over global environmental problems, the water hydraulic technique using pure tap water as a pressure medium has become a new drive source comparable to electric, oil hydraulic, and pneumatic drive systems. This technique is also preferred because of its high power density, high safety against fire hazards in production plants, and easy availability. However, the main problems for precise control in a water hydraulic system are steady state errors and overshoot due to its large friction torque and considerable leakage flow. MRAC has been already applied to compensate for these effects, and better control performances have been obtained. However, there have been no reports on the application of SAC for water hydraulics. To make clear the merits of SAC, the tracking control performance and robustness are discussed based on experimental results. SAC is confirmed to give better tracking performance compared with PI control, and a control precision comparable to MRAC (within 10 μm of the reference position) and higher robustness to parameter change, despite the simple controller. The research results ensure a wider application of simple adaptive control in real mechanical systems.

Poverty, population and environmental degradation in China.

PubMed

Rozelle, S; Huang, J; Zhang, L

1997-06-01

This article examines the relationship between poverty, population, and environmental degradation in China. Environmental conditions include water pollution, deforestation, destruction of grasslands, soil erosion, and salinization. The authors review China's success in controlling environmental degradation through leadership, environmental policies, and institutional capacity. Findings suggest that environmental progress is best achieved indirectly by poverty alleviation, market integration, and population control. Government policies were not very effective. Degradation occurs due to limited financial resources, poorly trained personnel, and political factors. Control of water pollution was instituted since the 1980s. The levels of pollutants have been reduced, but the type of pollutant determines the seriousness of impact. Water pollution is due to industrial wastes, agricultural run-off, and soil erosion. Since the 1970s, reforestation targets have not been met. Technical extension and monitoring of planting is not available in most areas, and private, profit seeking interests control acreage. Grassland destruction is due to deforestation, agricultural expansion, and overgrazing. Independent regional authorities have successfully managed pasture programs. Erosion is the most serious in Loess Plateau, the Red Soils area, the Northeast China Plain, and the Northwest Grasslands, which comprise 70% of total land area. In 1990, erosion control was practiced in 39% of eroded land area. Salinization has remained fairly constant. Environmental controls (direct regulation, planned recovery, and state-mandated technological improvements) are uneven. The main tool for environmental management is the State Environmental Protection Commission and its executive unit, SEPA. Problems stem from vague laws, lack of means of enforcement, lack of coordination of laws, and lack of standards, schedules, and other provisions in ordinances.

Pattern analysis of patients with temporomandibular disorders resulting from unilateral mastication due to chronic periodontitis

PubMed Central

2017-01-01

Purpose The purpose of the present study was to perform a pattern analysis in patients with temporomandibular disorder (TMD) resulting from unilateral mastication due to chronic periodontitis. Methods Thirty participants with signs or symptoms of TMD who engaged in unilateral mastication due to periodontitis-related discomfort (test group) were selected. Another 30 subjects exhibiting signs or symptoms of TMD resulting from unilateral mastication not due to chronic periodontitis (control group) were also recruited. An interview-based questionnaire was administered, and an examination of the temporomandibular joint (TMJ) with determination of periodontal status was performed. Results The duration of unilateral mastication was significantly longer in the control group than in the test group. There was a significant negative correlation between the duration of unilateral mastication and the Community Periodontal Index score. Using the Research Diagnostic Criteria for TMD (RDC/TMD) axis I algorithms, all the subjects were assigned to 3 main groups. The test group exhibited significantly a higher diagnostic distribution of group III (arthralgia, osteoarthritis, or osteoarthrosis), and in both the test and control groups, the number of diagnoses was larger for the non-chewing side. The control group showed a significantly higher diagnostic distribution of group I (myofacial pain), and in both the test and control groups, the number of diagnoses was larger for the chewing side. Conclusions The results of the present study indicate that unilateral mastication due to chronic periodontitis could induce not only pain but also structural TMJ changes if adequate treatment is not administered and supported within a short time from the onset of the condition. Therefore, immediate treatment of chronic periodontitis is recommended to prevent not only the primary progress of periodontal disease, but also secondary TMJ-related problems. Furthermore, subjects who have suffered chronic long-term periodontitis without treatment should be urged to undergo a TMJ examination. PMID:28861285

Working conditions as risk factors for disability retirement: a longitudinal register linkage study

PubMed Central

2012-01-01

Background Early retirement due to disability is a public health and work environment problem that shortens working careers. Transition to disability retirement is based on ill-health, but working conditions are also of relevance. We examined the contributions of work arrangements, physical working conditions and psychosocial working conditions to subsequent disability retirement. Methods The data were derived from the Helsinki Health Study cohort on employees of the City of Helsinki, Finland. Information on working conditions was obtained from the baseline surveys conducted in 2000, 2001 and 2002. These data were linked with register data on disability retirement and their main diagnoses obtained from the Finnish Centre for Pensions. Follow up by the end of 2008 yielded 525 disability retirement events. The analysed data included 6525 participants and 525 disability retirement events. Hazard ratios (HR) and 95% confidence intervals (95% CI) were calculated from Cox regression analysis. Results Several working conditions showed own associations with disability retirement before adjustment. After adjustment for all working conditions, the primary risk factors for all-cause disability retirement were physical workload among women (HR 2.02, 95% CI 1.57-2.59) and men (HR 2.00, 95% CI 1.18-3.38), and low job control among women (HR 1.60, 95% CI 1.29-1.99). In addition, for disability retirement due to musculoskeletal causes, the risk factors were physical workload and low job control. For disability retirement due to mental causes the risk factors were computer work and low job control. Furthermore, occupational class was a risk factor for disability retirement due to all causes and musculoskeletal diseases. Conclusions Among various working conditions, those that are physically demanding and those that imply low job control are potential risk factors for disability retirement. Improving the physical working environment and enhancing control over one’s job is likely to help prevent early retirement due to disability. PMID:22537302

Adapting Experiential Learning to Develop Problem-Solving Skills in Deaf and Hard-of-Hearing Engineering Students.

PubMed

Marshall, Matthew M; Carrano, Andres L; Dannels, Wendy A

2016-10-01

Individuals who are deaf and hard-of-hearing (DHH) are underrepresented in science, technology, engineering, and mathematics (STEM) professions, and this may be due in part to their level of preparation in the development and retention of mathematical and problem-solving skills. An approach was developed that incorporates experiential learning and best practices of STEM instruction to give first-year DHH students enrolled in a postsecondary STEM program the opportunity to develop problem-solving skills in real-world scenarios. Using an industrial engineering laboratory that provides manufacturing and warehousing environments, students were immersed in real-world scenarios in which they worked on teams to address prescribed problems encountered during the activities. The highly structured, Plan-Do-Check-Act approach commonly used in industry was adapted for the DHH student participants to document and communicate the problem-solving steps. Students who experienced the intervention realized a 14.6% improvement in problem-solving proficiency compared with a control group, and this gain was retained at 6 and 12 months, post-intervention. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The inverse problems of wing panel manufacture processes

NASA Astrophysics Data System (ADS)

Oleinikov, A. I.; Bormotin, K. S.

2013-12-01

It is shown that inverse problems of steady-state creep bending of plates in both the geometrically linear and nonlinear formulations can be represented in a variational formulation. Steady-state values of the obtained functionals corresponding to the solutions of the problems of inelastic deformation and springback are determined by applying a finite element procedure to the functionals. Optimal laws of creep deformation are formulated using the criterion of minimizing damage in the functionals of the inverse problems. The formulated problems are reduced to the problems solved by the finite element method using MSC.Marc software. Currently, forming of light metals poses tremendous challenges due to their low ductility at room temperature and their unusual deformation characteristics at hot-cold work: strong asymmetry between tensile and compressive behavior, and a very pronounced anisotropy. We used the constitutive models of steady-state creep of initially transverse isotropy structural materials the kind of the stress state has influence. The paper gives basics of the developed computer-aided system of design, modeling, and electronic simulation targeting the processes of manufacture of wing integral panels. The modeling results can be used to calculate the die tooling, determine the panel processibility, and control panel rejection in the course of forming.

Enhancements on the Convex Programming Based Powered Descent Guidance Algorithm for Mars Landing

NASA Technical Reports Server (NTRS)

Acikmese, Behcet; Blackmore, Lars; Scharf, Daniel P.; Wolf, Aron

2008-01-01

In this paper, we present enhancements on the powered descent guidance algorithm developed for Mars pinpoint landing. The guidance algorithm solves the powered descent minimum fuel trajectory optimization problem via a direct numerical method. Our main contribution is to formulate the trajectory optimization problem, which has nonconvex control constraints, as a finite dimensional convex optimization problem, specifically as a finite dimensional second order cone programming (SOCP) problem. SOCP is a subclass of convex programming, and there are efficient SOCP solvers with deterministic convergence properties. Hence, the resulting guidance algorithm can potentially be implemented onboard a spacecraft for real-time applications. Particularly, this paper discusses the algorithmic improvements obtained by: (i) Using an efficient approach to choose the optimal time-of-flight; (ii) Using a computationally inexpensive way to detect the feasibility/ infeasibility of the problem due to the thrust-to-weight constraint; (iii) Incorporating the rotation rate of the planet into the problem formulation; (iv) Developing additional constraints on the position and velocity to guarantee no-subsurface flight between the time samples of the temporal discretization; (v) Developing a fuel-limited targeting algorithm; (vi) Initial result on developing an onboard table lookup method to obtain almost fuel optimal solutions in real-time.

Density Control of Multi-Agent Systems with Safety Constraints: A Markov Chain Approach

NASA Astrophysics Data System (ADS)

Demirer, Nazli

The control of systems with autonomous mobile agents has been a point of interest recently, with many applications like surveillance, coverage, searching over an area with probabilistic target locations or exploring an area. In all of these applications, the main goal of the swarm is to distribute itself over an operational space to achieve mission objectives specified by the density of swarm. This research focuses on the problem of controlling the distribution of multi-agent systems considering a hierarchical control structure where the whole swarm coordination is achieved at the high-level and individual vehicle/agent control is managed at the low-level. High-level coordination algorithms uses macroscopic models that describes the collective behavior of the whole swarm and specify the agent motion commands, whose execution will lead to the desired swarm behavior. The low-level control laws execute the motion to follow these commands at the agent level. The main objective of this research is to develop high-level decision control policies and algorithms to achieve physically realizable commanding of the agents by imposing mission constraints on the distribution. We also make some connections with decentralized low-level motion control. This dissertation proposes a Markov chain based method to control the density distribution of the whole system where the implementation can be achieved in a decentralized manner with no communication between agents since establishing communication with large number of agents is highly challenging. The ultimate goal is to guide the overall density distribution of the system to a prescribed steady-state desired distribution while satisfying desired transition and safety constraints. Here, the desired distribution is determined based on the mission requirements, for example in the application of area search, the desired distribution should match closely with the probabilistic target locations. The proposed method is applicable for both systems with a single agent and systems with large number of agents due to the probabilistic nature, where the probability distribution of each agent's state evolves according to a finite-state and discrete-time Markov chain (MC). Hence, designing proper decision control policies requires numerically tractable solution methods for the synthesis of Markov chains. The synthesis problem has the form of a Linear Matrix Inequality Problem (LMI), with LMI formulation of the constraints. To this end, we propose convex necessary and sufficient conditions for safety constraints in Markov chains, which is a novel result in the Markov chain literature. In addition to LMI-based, offline, Markov matrix synthesis method, we also propose a QP-based, online, method to compute a time-varying Markov matrix based on the real-time density feedback. Both problems are convex optimization problems that can be solved in a reliable and tractable way, utilizing existing tools in the literature. A Low Earth Orbit (LEO) swarm simulations are presented to validate the effectiveness of the proposed algorithms. Another problem tackled as a part of this research is the generalization of the density control problem to autonomous mobile agents with two control modes: ON and OFF. Here, each mode consists of a (possibly overlapping) finite set of actions, that is, there exist a set of actions for the ON mode and another set for the OFF mode. We give formulation for a new Markov chain synthesis problem, with additional measurements for the state transitions, where a policy is designed to ensure desired safety and convergence properties for the underlying Markov chain.

A Children of Twins Study of parental divorce and offspring psychopathology

PubMed Central

D'Onofrio, Brian M.; Turkheimer, Eric; Emery, Robert E.; Maes, Hermine H.; Silberg, Judy; Eaves, Lindon J.

2010-01-01

Background Although parental divorce is associated with increased substance use and internalizing problems, experiencing the separation of one's parents may not cause these outcomes. The relations may be due to genetic or environmental selection factors, characteristics that lead to both marital separation and offspring functioning. Method We used the Children of Twins (CoT) Design to explore whether unmeasured genetic or environmental factors related to the twin parent, and measured characteristics of both parents, account for the association between parental divorce and offspring substance use and internalizing problems. Results The association between parental divorce and offspring substance use problems remained robust when controlling for genetic and environmental risk from the twin parent associated with parental divorce, and measured characteristics of both parents. The results do not prove, but are consistent with, a causal connection. In contrast, the analyses suggest that shared genetic liability in parents and their offspring accounts for the increased risk of internalizing problems in adult offspring from divorced families. Conclusions The study illustrates that unmeasured genetic and environmental selection factors must be considered when studying parental divorce. In explaining associations between parental divorce and young-adult adjustment, our evidence suggests that selection versus causal mechanisms may operate differently for substance abuse (a causal relation) and internalizing problems (an artifact of selection). The CoT design only controls for the genetic and environmental characteristics of one parent; thus, additional genetically informed analyses are needed. PMID:17593147

Nonlinear frequency response based adaptive vibration controller design for a class of nonlinear systems

NASA Astrophysics Data System (ADS)

Thenozhi, Suresh; Tang, Yu

2018-01-01

Frequency response functions (FRF) are often used in the vibration controller design problems of mechanical systems. Unlike linear systems, the FRF derivation for nonlinear systems is not trivial due to their complex behaviors. To address this issue, the convergence property of nonlinear systems can be studied using convergence analysis. For a class of time-invariant nonlinear systems termed as convergent systems, the nonlinear FRF can be obtained. The present paper proposes a nonlinear FRF based adaptive vibration controller design for a mechanical system with cubic damping nonlinearity and a satellite system. Here the controller gains are tuned such that a desired closed-loop frequency response for a band of harmonic excitations is achieved. Unlike the system with cubic damping, the satellite system is not convergent, therefore an additional controller is utilized to achieve the convergence property. Finally, numerical examples are provided to illustrate the effectiveness of the proposed controller.

Switching LPV Control with Double-Layer LPV Model for Aero-Engines

NASA Astrophysics Data System (ADS)

Tang, Lili; Huang, Jinquan; Pan, Muxuan

2017-11-01

To cover the whole range of operating conditions of aero-engine, a double-layer LPV model is built so as to take into account of the variability due to the flight altitude, Mach number and the rotational speed. With this framework, the problem of designing LPV state-feedback robust controller that guarantees desired bounds on both H_∞ and H_2 performances is considered. Besides this, to reduce the conservativeness caused by a single LPV controller of the whole flight envelope and the common Lyapunov function method, a new method is proposed to design a family of LPV switching controllers. The switching LPV controllers can ensure that the closed-loop system remains stable in the sense of Lyapunov under arbitrary switching logic. Meanwhile, the switching LPV controllers can ensure the parameters change smoothly. The validity and performance of the theoretical results are demonstrated through a numerical example.

Simulation and Development of Internal Model Control Applications in the Bayer Process

NASA Astrophysics Data System (ADS)

Colombé, Ph.; Dablainville, R.; Vacarisas, J.

Traditional PID feedback control system is limited in its use in the Bayer cycle due to the important and omnipresent time delays which can lead to stability problems and sluggish response. Advanced modern control techniques are available, but suffer in an industrial environment from a lack of simplicity and robustness. In this respect the Internal Model Control (IMC) method may be considered as an exception. After a brief review of the basic theoretical principles behind IMC, an IMC scheme is developed to work with single-input, single-output, discrete-time, nonlinear systems. Two applications of IMC in the Bayer process, both in simulations and on industrial plants, are then described: control of the caustic soda concentration of the aluminate liquor and control of the A12O3/Na20 caust. ratio of the digested slurry, Finally, the results obtained make this technique quite attractive for the alumina industry.

Research on output feedback control

NASA Technical Reports Server (NTRS)

Calise, A. J.; Kramer, F. S.

1985-01-01

In designing fixed order compensators, an output feedback formulation has been adopted by suitably augmenting the system description to include the compensator states. However, the minimization of the performance index over the range of possible compensator descriptions was impeded due to the nonuniqueness of the compensator transfer function. A controller canonical form of the compensator was chosen to reduce the number of free parameters to its minimal number in the optimization. In the MIMO case, the controller form requires a prespecified set of ascending controllability indices. This constraint on the compensator structure is rather innocuous in relation to the increase in convergence rate of the optimization. Moreover, the controller form is easily relatable to a unique controller transfer function description. This structure of the compensator does not require penalizing the compensator states for a nonzero or coupled solution, a problem that occurs when following a standard output feedback synthesis formulation.

Tracked robot controllers for climbing obstacles autonomously

NASA Astrophysics Data System (ADS)

Vincent, Isabelle

2009-05-01

Research in mobile robot navigation has demonstrated some success in navigating flat indoor environments while avoiding obstacles. However, the challenge of analyzing complex environments to climb obstacles autonomously has had very little success due to the complexity of the task. Unmanned ground vehicles currently exhibit simple autonomous behaviours compared to the human ability to move in the world. This paper presents the control algorithms designed for a tracked mobile robot to autonomously climb obstacles by varying its tracks configuration. Two control algorithms are proposed to solve the autonomous locomotion problem for climbing obstacles. First, a reactive controller evaluates the appropriate geometric configuration based on terrain and vehicle geometric considerations. Then, a reinforcement learning algorithm finds alternative solutions when the reactive controller gets stuck while climbing an obstacle. The methodology combines reactivity to learning. The controllers have been demonstrated in box and stair climbing simulations. The experiments illustrate the effectiveness of the proposed approach for crossing obstacles.

Problems in diagnosis and treatment of tuberculosis infection.

PubMed

Tsara, V; Serasli, E; Christaki, P

2009-01-01

Tuberculosis is still a major health problem in industrialized countries due to specific socioeconomic factors and there is the growing need of new rapid and accurate diagnostic methods, in order to achieve higher sensitivity and specificity compared to traditional methods of microscopic sputum examination and culture. Such methods, recently introduced, are nucleic acid amplification (NAA) tests, used directly on clinical specimens and blood tests (QuantiFERON-TB, T-SPOT.TB test), measuring the IFN-gamma released by stimulated T cells. Furthermore, new drugs for the disease need to be developed, aiming to better treatment results and to prevention of Multiple Drug Resistance (MDR) cases. Critical aspects in the management of drug resistance cases should be the careful choices of drugs combination, the close follow up of the patients alongside with the patients adherence to therapy. The role of national and international tuberculosis programs is invaluable in TB control and therapy, as well as the collaboration of all the health system departments. However, most of the clinical problems that may arise are addressed by the International Standards for Tuberculosis Care-ISTC and these guidelines should be taken into consideration, at least until future research provides more promising diagnostic and therapeutic modalities for control of the disease.

Simulation and optimization of an experimental membrane wastewater treatment plant using computational intelligence methods.

PubMed

Ludwig, T; Kern, P; Bongards, M; Wolf, C

2011-01-01

The optimization of relaxation and filtration times of submerged microfiltration flat modules in membrane bioreactors used for municipal wastewater treatment is essential for efficient plant operation. However, the optimization and control of such plants and their filtration processes is a challenging problem due to the underlying highly nonlinear and complex processes. This paper presents the use of genetic algorithms for this optimization problem in conjunction with a fully calibrated simulation model, as computational intelligence methods are perfectly suited to the nonconvex multi-objective nature of the optimization problems posed by these complex systems. The simulation model is developed and calibrated using membrane modules from the wastewater simulation software GPS-X based on the Activated Sludge Model No.1 (ASM1). Simulation results have been validated at a technical reference plant. They clearly show that filtration process costs for cleaning and energy can be reduced significantly by intelligent process optimization.

Uncertainty management by relaxation of conflicting constraints in production process scheduling

NASA Technical Reports Server (NTRS)

Dorn, Juergen; Slany, Wolfgang; Stary, Christian

1992-01-01

Mathematical-analytical methods as used in Operations Research approaches are often insufficient for scheduling problems. This is due to three reasons: the combinatorial complexity of the search space, conflicting objectives for production optimization, and the uncertainty in the production process. Knowledge-based techniques, especially approximate reasoning and constraint relaxation, are promising ways to overcome these problems. A case study from an industrial CIM environment, namely high-grade steel production, is presented to demonstrate how knowledge-based scheduling with the desired capabilities could work. By using fuzzy set theory, the applied knowledge representation technique covers the uncertainty inherent in the problem domain. Based on this knowledge representation, a classification of jobs according to their importance is defined which is then used for the straightforward generation of a schedule. A control strategy which comprises organizational, spatial, temporal, and chemical constraints is introduced. The strategy supports the dynamic relaxation of conflicting constraints in order to improve tentative schedules.

The Role of Functional Foods, Nutraceuticals, and Food Supplements in Intestinal Health

PubMed Central

Cencic, Avrelija; Chingwaru, Walter

2010-01-01

New eating habits, actual trends in production and consumption have a health, environmental and social impact. The European Union is fighting diseases characteristic of a modern age, such as obesity, osteoporosis, cancer, diabetes, allergies and dental problems. Developed countries are also faced with problems relating to aging populations, high energy foods, and unbalanced diets. The potential of nutraceuticals/functional foods/food supplements in mitigating health problems, especially in the gastrointestinal (GI) tract, is discussed. Certain members of gut microflora (e.g., probiotic/protective strains) play a role in the host health due to its involvement in nutritional, immunologic and physiological functions. The potential mechanisms by which nutraceuticals/functional foods/food supplements may alter a host’s health are also highlighted in this paper. The establishment of novel functional cell models of the GI and analytical tools that allow tests in controlled experiments are highly desired for gut research. PMID:22254045

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

Moore, Thomas W.; Quach, Tu-Thach; Detry, Richard Joseph

Complex Adaptive Systems of Systems, or CASoS, are vastly complex ecological, sociological, economic and/or technical systems which we must understand to design a secure future for the nation and the world. Perturbations/disruptions in CASoS have the potential for far-reaching effects due to pervasive interdependencies and attendant vulnerabilities to cascades in associated systems. Phoenix was initiated to address this high-impact problem space as engineers. Our overarching goals are maximizing security, maximizing health, and minimizing risk. We design interventions, or problem solutions, that influence CASoS to achieve specific aspirations. Through application to real-world problems, Phoenix is evolving the principles and discipline ofmore » CASoS Engineering while growing a community of practice and the CASoS engineers to populate it. Both grounded in reality and working to extend our understanding and control of that reality, Phoenix is at the same time a solution within a CASoS and a CASoS itself.« less

Design and application of discrete wavelet packet transform based multiresolution controller for liquid level system.

PubMed

Paul, Rimi; Sengupta, Anindita

2017-11-01

A new controller based on discrete wavelet packet transform (DWPT) for liquid level system (LLS) has been presented here. This controller generates control signal using node coefficients of the error signal which interprets many implicit phenomena such as process dynamics, measurement noise and effect of external disturbances. Through simulation results on LLS problem, this controller is shown to perform faster than both the discrete wavelet transform based controller and conventional proportional integral controller. Also, it is more efficient in terms of its ability to provide better noise rejection. To overcome the wind up phenomenon by considering the saturation due to presence of actuator, anti-wind up technique is applied to the conventional PI controller and compared to the wavelet packet transform based controller. In this case also, packet controller is found better than the other ones. This similar work has been extended for analogous first order RC plant as well as second order plant also. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Collection of Light From an Optical Fiber With a Numerical Aperture Greater Than One

NASA Technical Reports Server (NTRS)

Egalon, Claudio O. (Inventor); Rogowski, Robert S. (Inventor)

1996-01-01

In an optical fiber having NA greater than 1, light may be internally reflected when it strikes the fiber end at a fiber-air interface. This problem may be overcome by modification of the fiber by reverse tapering the core. Light is redirected by the taper to strike the interface at an angle closer to normal. This allows light to exit the fiber end that would by internally reflected in an untapered fiber of NA greater than 1. The novelty of the present invention lies in the tapering of the fiber core for increased through transmission of light. Prior art devices have made use of fiber tapers to achieve mode control or fiber coupling. The problem of internal reflection has not been addressed as it is one that is not as important in fibers having NA less than 1, which are more common. In chemical sensing it is advantageous to make use of fibers having higher NA due to an increased sensitivity. However the advantages in sensitivity are diminished due to the loss of signal at the fiber-air interface. The present invention overcomes the problem of loss at the interface, thus facilitating the use of high NA fibers for chemical sensing.

Problem behaviour and traumatic dental injuries in adolescents.

PubMed

Ramchandani, Damini; Marcenes, Wagner; Stansfeld, Stephen A; Bernabé, Eduardo

2016-02-01

To explore the relationship between problem behaviour and traumatic dental injuries (TDI) among 15- to 16-year-old schoolchildren from East London. This cross-sectional study used data from 794 adolescents who participated in phase III of the Research with East London Adolescents Community Health Survey (RELACHS), a school-based prospective study of a representative sample of adolescents. Participants completed a questionnaire and were clinically examined for TDI, overjet and lip coverage. The Strength and Difficulties Questionnaire (SDQ) was used to assess problem behaviour, which provided a total score and five domain scores (emotional symptoms, conduct problems, hyperactivity, peer problems and pro-social behaviour). The association between problem behaviour and TDI was assessed in unadjusted and adjusted logistic regression models. Adjusted models controlled for demographic (sex, age and ethnicity), socio-economic (parental employment) and clinical factors (overjet and lip coverage). The prevalence of TDI was 17% and the prevalence of problem behaviour, according to the SDQ, was 10%. In the adjusted model, adolescents with problem behaviour were 1.87 (95% confidence interval: 1.03-3.37) times more likely to have TDI than those without problem behaviour. In subsequent analysis by SDQ domains, it was found that only peer problems were associated with TDI (OR = 1.78, 95% CI: 1.01-3.14), even after adjustment for confounders. This study found evidence for a relationship between problem behaviour and TDI among adolescents, which was mainly due to peer relationship problems. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

An extended smart utilization medium access control (ESU-MAC) protocol for ad hoc wireless systems

NASA Astrophysics Data System (ADS)

Vashishtha, Jyoti; Sinha, Aakash

2006-05-01

The demand for spontaneous setup of a wireless communication system has increased in recent years for areas like battlefield, disaster relief operations etc., where a pre-deployment of network infrastructure is difficult or unavailable. A mobile ad-hoc network (MANET) is a promising solution, but poses a lot of challenges for all the design layers, specifically medium access control (MAC) layer. Recent existing works have used the concepts of multi-channel and power control in designing MAC layer protocols. SU-MAC developed by the same authors, efficiently uses the 'available' data and control bandwidth to send control information and results in increased throughput via decreasing contention on the control channel. However, SU-MAC protocol was limited for static ad-hoc network and also faced the busy-receiver node problem. We present the Extended SU-MAC (ESU-MAC) protocol which works mobile nodes. Also, we significantly improve the scheme of control information exchange in ESU-MAC to overcome the busy-receiver node problem and thus, further avoid the blockage of control channel for longer periods of time. A power control scheme is used as before to reduce interference and to effectively re-use the available bandwidth. Simulation results show that ESU-MAC protocol is promising for mobile, ad-hoc network in terms of reduced contention at the control channel and improved throughput because of channel re-use. Results show a considerable increase in throughput compared to SU-MAC which could be attributed to increased accessibility of control channel and improved utilization of data channels due to superior control information exchange scheme.

Locust bean gum: processing, properties and food applications--a review.

PubMed

Barak, Sheweta; Mudgil, Deepak

2014-05-01

Locust bean gum or carob gum is a galactomannan obtained from seed endosperm of carob tree i.e. Ceratonia siliqua. It is widely utilized as an additive in various industries such as food, pharmaceuticals, paper, textile, oil well drilling and cosmetics. Industrial applications of locust bean gum are due to its ability to form hydrogen bonding with water molecule. It is also beneficial in the control of many health problems like diabetes, bowel movements, heart disease and colon cancer due to its dietary fiber action. This article focuses on production, processing, composition, properties, food applications and health benefits of locust bean gum. Copyright © 2014 Elsevier B.V. All rights reserved.

[Pathophysiological aspects of wound healing in normal and diabetic foot].

PubMed

Maksimova, N V; Lyundup, A V; Lubimov, R O; Melnichenko, G A; Nikolenko, V N

2014-01-01

The main cause of long-term healing of ulcers in patients with diabetic foot is considered to be direct mechanical damage when walking due to reduced sensitivity to due to neuropathy, hyperglycemia, infection and peripheral artery disease. These factors determine the standard approaches to the treatment of diabeticfoot, which include: offloading, glycemic control, debridement of ulcers, antibiotic therapy and revascularization. Recently, however, disturbances in the healing process of the skin in diabetes recognized an additional factor affecting the timing of healing patients with diabetic foot. Improved understanding and correction of cellular, molecular and biochemical abnormalities in chronic wound in combination with standard of care for affords new ground for solving the problem of ulcer healing in diabetes.

Identifying and attributing common data quality problems: temperature and precipitation observations in Bolivia and Peru

NASA Astrophysics Data System (ADS)

Hunziker, Stefan; Gubler, Stefanie; Calle, Juan; Moreno, Isabel; Andrade, Marcos; Velarde, Fernando; Ticona, Laura; Carrasco, Gualberto; Castellón, Yaruska; Oria Rojas, Clara; Brönnimann, Stefan; Croci-Maspoli, Mischa; Konzelmann, Thomas; Rohrer, Mario

2016-04-01

Assessing climatological trends and extreme events requires high-quality data. However, for many regions of the world, observational data of the desired quality is not available. In order to eliminate errors in the data, quality control (QC) should be applied before data analysis. If the data still contains undetected errors and quality problems after QC, a consequence may be misleading and erroneous results. A region which is seriously affected by observational data quality problems is the Central Andes. At the same time, climatological information on ongoing climate change and climate risks are of utmost importance in this area due to its vulnerability to meteorological extreme events and climatic changes. Beside data quality issues, the lack of metadata and the low station network density complicate quality control and assessment, and hence, appropriate application of the data. Errors and data problems may occur at any point of the data generation chain, e.g. due to unsuitable station configuration or siting, poor station maintenance, erroneous instrument reading, or inaccurate data digitalization and post processing. Different measurement conditions in the predominantly conventional station networks in Bolivia and Peru compared to the mostly automated networks e.g. in Europe or Northern America may cause different types of errors. Hence, applying QC methods used on state of the art networks to Bolivian and Peruvian climate observations may not be suitable or sufficient. A comprehensive amount of Bolivian and Peruvian maximum and minimum temperature and precipitation in-situ measurements were analyzed to detect and describe common data quality problems. Furthermore, station visits and reviews of the original documents were done. Some of the errors could be attributed to a specific source. Such information is of great importance for data users, since it allows them to decide for what applications the data still can be used. In ideal cases, it may even allow to correct the error. Strategies on how to deal with data from the Central Andes will be suggested. However, the approach may be applicable to networks from other countries where conditions of climate observations are comparable.

MIDSHIPS: multicentre intervention designed for self-harm using interpersonal problem-solving: protocol for a randomised controlled feasibility study.

PubMed

Collinson, Michelle; Owens, David; Blenkiron, Paul; Burton, Kayleigh; Graham, Liz; Hatcher, Simon; House, Allan; Martin, Katie; Pembroke, Louise; Protheroe, David; Tubeuf, Sandy; Farrin, Amanda

2014-05-10

Around 150,000 people each year attend hospitals in England due to self-harm, many of them more than once. Over 5,000 people die by suicide each year in the UK, a quarter of them having attended hospital in the previous year because of self-harm. Self-harm is a major identifiable risk factor for suicide. People receive variable care at hospital; many are not assessed for their psychological needs and little psychological therapy is offered. Despite its frequent occurrence, we have no clear research evidence about how to reduce the repetition of self-harm. Some people who have self-harmed show less active ways of solving problems, and brief problem-solving therapies are considered the most promising psychological treatments. This is a pragmatic, individually randomised, controlled, feasibility study comparing interpersonal problem-solving therapy plus treatment-as-usual with treatment-as-usual alone, for adults attending a general hospital following self-harm. A total of 60 participants will be randomised equally between the treatment arms, which will be balanced with respect to the type of most recent self-harm event, number of previous self-harm events, gender and age. Feasibility objectives are as follows: a) To establish and field test procedures for implementing the problem-solving intervention; b) To determine the feasibility and best method of participant recruitment and follow up; c) To assess therapeutic delivery; d) To assess the feasibility of obtaining the definitive trial's primary and secondary outcomes; e) To assess the perceived burden and acceptability of obtaining the trial's self-reported outcome data; f) To inform the sample size calculation for the definitive trial. The results of this feasibility study will be used to determine the appropriateness of proceeding to a definitive trial and will allow us to design an achievable trial of interpersonal problem-solving therapy for adults who self-harm. Current Controlled Trials (ISRCTN54036115).

MIDSHIPS: Multicentre Intervention Designed for Self-Harm using Interpersonal Problem-Solving: protocol for a randomised controlled feasibility study

PubMed Central

2014-01-01

Background Around 150,000 people each year attend hospitals in England due to self-harm, many of them more than once. Over 5,000 people die by suicide each year in the UK, a quarter of them having attended hospital in the previous year because of self-harm. Self-harm is a major identifiable risk factor for suicide. People receive variable care at hospital; many are not assessed for their psychological needs and little psychological therapy is offered. Despite its frequent occurrence, we have no clear research evidence about how to reduce the repetition of self-harm. Some people who have self-harmed show less active ways of solving problems, and brief problem-solving therapies are considered the most promising psychological treatments. Methods/Design This is a pragmatic, individually randomised, controlled, feasibility study comparing interpersonal problem-solving therapy plus treatment-as-usual with treatment-as-usual alone, for adults attending a general hospital following self-harm. A total of 60 participants will be randomised equally between the treatment arms, which will be balanced with respect to the type of most recent self-harm event, number of previous self-harm events, gender and age. Feasibility objectives are as follows: a) To establish and field test procedures for implementing the problem-solving intervention; b) To determine the feasibility and best method of participant recruitment and follow up; c) To assess therapeutic delivery; d) To assess the feasibility of obtaining the definitive trial’s primary and secondary outcomes; e) To assess the perceived burden and acceptability of obtaining the trial’s self-reported outcome data; f) To inform the sample size calculation for the definitive trial. Discussion The results of this feasibility study will be used to determine the appropriateness of proceeding to a definitive trial and will allow us to design an achievable trial of interpersonal problem-solving therapy for adults who self-harm. Trial registration Current Controlled Trials (ISRCTN54036115) PMID:24886683

Feed Forward Neural Network and Optimal Control Problem with Control and State Constraints

NASA Astrophysics Data System (ADS)

Kmet', Tibor; Kmet'ová, Mária

2009-09-01

A feed forward neural network based optimal control synthesis is presented for solving optimal control problems with control and state constraints. The paper extends adaptive critic neural network architecture proposed by [5] to the optimal control problems with control and state constraints. The optimal control problem is transcribed into a nonlinear programming problem which is implemented with adaptive critic neural network. The proposed simulation method is illustrated by the optimal control problem of nitrogen transformation cycle model. Results show that adaptive critic based systematic approach holds promise for obtaining the optimal control with control and state constraints.

A fish-like robot: Mechanics of swimming due to constraints

NASA Astrophysics Data System (ADS)

Tallapragada, Phanindra; Malla, Rijan

2014-11-01

It is well known that due to reasons of symmetry, a body with one degree of actuation cannot swim in an ideal fluid. However certain velocity constraints arising in fluid-body interactions, such as the Kutta condition classically applied at the trailing cusp of a Joukowski hydrofoil break this symmetry through vortex shedding. Thus Joukowski foils that vary shape periodically can be shown to be able to swim through vortex shedding. In general it can be shown that vortex shedding due to the Kutta condition is equivalent to nonintegrable constraints arising in the mechanics of finite-dimensional mechanical systems. This equivalence allows hydrodynamic problems involving vortex shedding, especially those pertaining to swimming and related phenomena to be framed in the context of geometric mechanics on manifolds. This formal equivalence also allows the design of bio inspired robots that swim not due to shape change but due to internal moving masses and rotors. Such robots lacking articulated joints are easy to design, build and control. We present such a fish-like robot that swims due to the rotation of internal rotors.

An original traffic additional emission model and numerical simulation on a signalized road

NASA Astrophysics Data System (ADS)

Zhu, Wen-Xing; Zhang, Jing-Yu

2017-02-01

Based on VSP (Vehicle Specific Power) model traffic real emissions were theoretically classified into two parts: basic emission and additional emission. An original additional emission model was presented to calculate the vehicle's emission due to the signal control effects. Car-following model was developed and used to describe the traffic behavior including cruising, accelerating, decelerating and idling at a signalized intersection. Simulations were conducted under two situations: single intersection and two adjacent intersections with their respective control policy. Results are in good agreement with the theoretical analysis. It is also proved that additional emission model may be used to design the signal control policy in our modern traffic system to solve the serious environmental problems.

Optimized cross-resonance gate for coupled transmon systems

NASA Astrophysics Data System (ADS)

Kirchhoff, Susanna; Keßler, Torsten; Liebermann, Per J.; Assémat, Elie; Machnes, Shai; Motzoi, Felix; Wilhelm, Frank K.

2018-04-01

The cross-resonance (CR) gate is an entangling gate for fixed-frequency superconducting qubits. While being simple and extensible, it is comparatively slow, at 160 ns, and thus of limited fidelity due to on-going incoherent processes. Using two different optimal control algorithms, we estimate the quantum speed limit for a controlled-not cnot gate in this system to be 10 ns, indicating a potential for great improvements. We show that the ability to approach this limit depends strongly on the choice of ansatz used to describe optimized control pulses and limitations placed on their complexity. Using a piecewise-constant ansatz, with a single carrier and bandwidth constraints, we identify an experimentally feasible 70-ns pulse shape. Further, an ansatz based on the two dominant frequencies involved in the optimal control problem allows for an optimal solution more than twice as fast again, at under 30 ns, with smooth features and limited complexity. This is twice as fast as gate realizations using tunable-frequency, resonantly coupled qubits. Compared to current CR-gate implementations, we project our scheme will provide a sixfold speed-up and thus a sixfold reduction in fidelity loss due to incoherent effects.

Acceleration and torque feedback for robotic control - Experimental results

NASA Technical Reports Server (NTRS)

Mclnroy, John E.; Saridis, George N.

1990-01-01

Gross motion control of robotic manipulators typically requires significant on-line computations to compensate for nonlinear dynamics due to gravity, Coriolis, centripetal, and friction nonlinearities. One controller proposed by Luo and Saridis avoids these computations by feeding back joint acceleration and torque. This study implements the controller on a Puma 600 robotic manipulator. Joint acceleration measurement is obtained by measuring linear accelerations of each joint, and deriving a computationally efficient transformation from the linear measurements to the angular accelerations. Torque feedback is obtained by using the previous torque sent to the joints. The implementation has stability problems on the Puma 600 due to the extremely high gains inherent in the feedback structure. Since these high gains excite frequency modes in the Puma 600, the algorithm is modified to decrease the gain inherent in the feedback structure. The resulting compensator is stable and insensitive to high frequency unmodeled dynamics. Moreover, a second compensator is proposed which uses acceleration and torque feedback, but still allows nonlinear terms to be fed forward. Thus, by feeding the increment in the easily calculated gravity terms forward, improved responses are obtained. Both proposed compensators are implemented, and the real time results are compared to those obtained with the computed torque algorithm.

Using insights from behavioral economics and social psychology to help patients manage chronic diseases.

PubMed

Mogler, Braden K; Shu, Suzanne B; Fox, Craig R; Goldstein, Noah J; Victor, Ronald G; Escarce, José J; Shapiro, Martin F

2013-05-01

Despite a revolution in therapeutics, the ability to control chronic diseases remains elusive. We present here a conceptual model of the potential role of behavioral tools in chronic disease control. Clinicians implicitly accept the assumption that patients will act rationally to maximize their self-interest. However, patients may not always be the rational actors that we imagine. Major behavioral barriers to optimal health behavior include patients' fear of threats to health, unwillingness to think about problems when risks are known or data are ambiguous, the discounting of risks that are far in the future, failure to act due to lack of motivation, insufficient confidence in the ability to overcome a health problem, and inattention due to pressures of everyday life. Financial incentives can stimulate initiation of health-promoting behaviors by reducing or eliminating financial barriers, but may not produce long-term behavior change without additional interventions. Strategies have been developed by behavioral economists and social psychologists to address each of these barriers to better decision-making. These include: labeling positive behaviors in ways consistent with patient life goals and priorities; greater focus on more immediate risks of chronic diseases; intermediate subgoals as steps to a large health goal; and implementation of specific plans as to when, where, and how an action will be taken. Such strategies hold promise for improving health behaviors and disease control, but most have not been studied in medical settings. The effectiveness of these approaches should be evaluated for their potential as tools for the clinician.

The Ulysses spacecraft control and monitoring concepts and realities

NASA Technical Reports Server (NTRS)

Hamer, Paul; Angold, Nigel

1993-01-01

Ulysses is a joint ESA-NASA mission, the primary purpose of the mission is to make scientific measurements of the Sun outside the plane of the ecliptic. The delay in launching Ulysses, due to the Challenger disaster, meant that the hardware on which the Spacecraft Control and Monitoring System (SCMS) resides was becoming obsolete, and it was decided to convert SCMS to run on a DEC/VAX machine under VMS. The paper will cover the spacecraft, the conversion, the converted SCMS, problems found, and the upgrades implemented for solutions. It will also discuss the future for and enhancements already made to the converted SCMS.

Guaranteed cost control with poles assignment for a flexible air-breathing hypersonic vehicle

NASA Astrophysics Data System (ADS)

Li, Hongyi; Si, Yulin; Wu, Ligang; Hu, Xiaoxiang; Gao, Huijun

2011-05-01

This article investigates the problem of guaranteed cost control for a flexible air-breathing hypersonic vehicle (FAHV). The FAHV includes intricate coupling between the engine and flight dynamics as well as complex interplay between flexible and rigid modes, which results in an intractable system for the control design. A longitudinal model is adopted for control design due to the complexity of the vehicle. First, for a highly nonlinear and coupled FAHV, a linearised model is established around the trim condition, which includes the state of altitude, velocity, angle of attack, pitch angle and pitch rate, etc. Secondly, by using the Lyapunov approach, performance analysis is carried out for the resulting closed-loop FAHV system, whose criterion with respect to guaranteed performance cost and poles assignment is expressed in the framework of linear matrix inequalities (LMIs). The established criterion exhibits a kind of decoupling between the Lyapunov positive-definite matrices to be determined and the FAHV system matrices, which is enabled by the introduction of additional slack matrix variables. Thirdly, a convex optimisation problem with LMI constraints is formulated for designing an admissible controller, which guarantees a prescribed performance cost with the simultaneous consideration of poles assignment for the resulting closed-loop system. Finally, some simulation results are provided to show that the guaranteed cost controller could assign the poles into the desired regional and achieve excellent reference altitude and velocity tracking performance.

IIR filtering based adaptive active vibration control methodology with online secondary path modeling using PZT actuators

NASA Astrophysics Data System (ADS)

Boz, Utku; Basdogan, Ipek

2015-12-01

Structural vibrations is a major cause for noise problems, discomfort and mechanical failures in aerospace, automotive and marine systems, which are mainly composed of plate-like structures. In order to reduce structural vibrations on these structures, active vibration control (AVC) is an effective approach. Adaptive filtering methodologies are preferred in AVC due to their ability to adjust themselves for varying dynamics of the structure during the operation. The filtered-X LMS (FXLMS) algorithm is a simple adaptive filtering algorithm widely implemented in active control applications. Proper implementation of FXLMS requires availability of a reference signal to mimic the disturbance and model of the dynamics between the control actuator and the error sensor, namely the secondary path. However, the controller output could interfere with the reference signal and the secondary path dynamics may change during the operation. This interference problem can be resolved by using an infinite impulse response (IIR) filter which considers feedback of the one or more previous control signals to the controller output and the changing secondary path dynamics can be updated using an online modeling technique. In this paper, IIR filtering based filtered-U LMS (FULMS) controller is combined with online secondary path modeling algorithm to suppress the vibrations of a plate-like structure. The results are validated through numerical and experimental studies. The results show that the FULMS with online secondary path modeling approach has more vibration rejection capabilities with higher convergence rate than the FXLMS counterpart.

Optimal control of build height utilizing optical profilometry in cold spray deposits

NASA Astrophysics Data System (ADS)

Chakraborty, Abhijit; Shishkin, Sergey; Birnkrant, Michael J.

2017-04-01

Part-to-part variability and poor part quality due to failure to maintain geometric specifications pose a challenge for adopting Additive Manufacturing (AM) as a viable manufacturing process. In recent years, In-process Monitoring and Control (InPMC) has received a lot of attention as an approach to overcome these obstacles. The ability to sense geometry of the deposited layers accurately enables effective process monitoring and control of AM application. This paper demonstrates an application of geometry sensing technique for the coating deposition Cold Spray process, where solid powders are accelerated through a nozzle, collides with the substrate and adheres to it. Often the deposited surface has shape irregularities. This paper proposes an approach to suppress the iregularities by controlling the deposition height. An analytical control-oriented model is developed that expresses the resulting height of deposit as an integral function of nozzle velocity and angle. In order to obtain height information at each layer, a Micro-Epsilon laser line scanner was used for surface profiling after each deposition. This surface profile information, specifically the layer height, was then fed back to an optimal control algorithm which manipulated the nozzle speed to control the layer height to a pre specified height. While the problem is heavily nonlinear, we were able to transform it into equivalent Optimal Control problem linear w.r.t. input. That enabled development of two solution methods: one is fast and approximate, while another is more accurate but still efficient.

Model predictive control of attitude maneuver of a geostationary flexible satellite based on genetic algorithm

NASA Astrophysics Data System (ADS)

TayyebTaher, M.; Esmaeilzadeh, S. Majid

2017-07-01

This article presents an application of Model Predictive Controller (MPC) to the attitude control of a geostationary flexible satellite. SIMO model has been used for the geostationary satellite, using the Lagrange equations. Flexibility is also included in the modelling equations. The state space equations are expressed in order to simplify the controller. Naturally there is no specific tuning rule to find the best parameters of an MPC controller which fits the desired controller. Being an intelligence method for optimizing problem, Genetic Algorithm has been used for optimizing the performance of MPC controller by tuning the controller parameter due to minimum rise time, settling time, overshoot of the target point of the flexible structure and its mode shape amplitudes to make large attitude maneuvers possible. The model included geosynchronous orbit environment and geostationary satellite parameters. The simulation results of the flexible satellite with attitude maneuver shows the efficiency of proposed optimization method in comparison with LQR optimal controller.

The Subject Matter of Process Improvement: A Topic and Reference Source for Software Engineering Educators and Trainers.

DTIC Science & Technology

1995-05-01

Random House Business Division, 1986. Ishikawa , Kaoru . What is Total Quality Control?: The Japanese Way. En- glewood Cliffs, NJ: Prentice-Hall...by drawing attention to the vital few truly important problems. Cause-and-effect diagrams. Also called fishbone and Ishikawa diagrams due to their...February 1994. 5.2 The Seeds [Aguayo 91] [Crosby 79] [Crosby 92] [Deming 86] [Fellers 92] [Gitlow 87] [Gluckman 93] [Imai 86] [ Ishikawa 85] [Juran

Enhanced Tools and Techniques to Support Debris Management in Disaster Response Missions (Flood and Coastal Storm Damage Reduction Research and Development Program)

DTIC Science & Technology

2009-05-01

debris removal without restoration is deployed.  Conduct a controlled field study of restoration activity, for example, along the Wabash ...hazardous metals including chromium, cadmium , lead and mercury (MDEQ 2008; Thibodeau 2002). 3. Batteries in electronics and computers may contain lead...mercury, nickel and cadmium . Appliances Appliances are a problem mainly due to their large size, creating issues with loading, hauling, and

Does hospital at home for palliative care facilitate death at home? Randomised controlled trial

PubMed Central

Grande, Gunn E; Todd, Chris J; Barclay, Stephen I G; Farquhar, Morag C

1999-01-01

Objective To evaluate the impact on place of death of a hospital at home service for palliative care. Design Pragmatic randomised controlled trial. Setting Former Cambridge health district. Participants 229 patients referred to the hospital at home service; 43 randomised to control group (standard care), 186 randomised to hospital at home. Intervention Hospital at home versus standard care. Main outcome measures Place of death. Results Twenty five (58%) control patients died at home compared with 124 (67%) patients allocated to hospital at home. This difference was not significant; intention to treat analysis did not show that hospital at home increased the number of deaths at home. Seventy three patients randomised to hospital at home were not admitted to the service. Patients admitted to hospital at home were significantly more likely to die at home (88/113; 78%) than control patients. It is not possible to determine whether this was due to hospital at home itself or other characteristics of the patients admitted to the service. The study attained less statistical power than initially planned. Conclusion In a locality with good provision of standard community care we could not show that hospital at home allowed more patients to die at home, although neither does the study refute this. Problems relating to recruitment, attrition, and the vulnerability of the patient group make randomised controlled trials in palliative care difficult. While these difficulties have to be recognised they are not insurmountable with the appropriate resourcing and setting. Key messagesTerminally ill patients allocated to hospital at home were no more likely to die at home than patients receiving standard careAlthough the subsample of patients actually admitted to hospital at home did show a significant increase in likelihood of dying at home, whether this was due to the service itself or the characteristics of patients admitted to hospital at home could not be determinedThe need to balance ideal research design against the realities of evaluation of palliative care had the effect that the trial achieved less statistical power than originally plannedParticular problems were that many patients failed to receive the allocated intervention because of the unpredictable nature of terminal illness, inclusion of other service input alongside hospital at home, and the wide range of standard care availableThe trial illustrated problems associated with randomised controlled trials in palliative care, none of which are insurmountable but which require careful consideration and resourcing before future trials are planned PMID:10582932

Three-Axis Time-Optimal Attitude Maneuvers of a Rigid-Body

NASA Astrophysics Data System (ADS)

Wang, Xijing; Li, Jisheng

With the development trends for modern satellites towards macro-scale and micro-scale, new demands are requested for its attitude adjustment. Precise pointing control and rapid maneuvering capabilities have long been part of many space missions. While the development of computer technology enables new optimal algorithms being used continuously, a powerful tool for solving problem is provided. Many papers about attitude adjustment have been published, the configurations of the spacecraft are considered rigid body with flexible parts or gyrostate-type systems. The object function always include minimum time or minimum fuel. During earlier satellite missions, the attitude acquisition was achieved by using the momentum ex change devices, performed by a sequential single-axis slewing strategy. Recently, the simultaneous three-axis minimum-time maneuver(reorientation) problems have been studied by many researchers. It is important to research the minimum-time maneuver of a rigid spacecraft within onboard power limits, because of potential space application such as surveying multiple targets in space and academic value. The minimum-time maneuver of a rigid spacecraft is a basic problem because the solutions for maneuvering flexible spacecraft are based on the solution to the rigid body slew problem. A new method for the open-loop solution for a rigid spacecraft maneuver is presented. Having neglected all perturbation torque, the necessary conditions of spacecraft from one state to another state can be determined. There is difference between single-axis with multi-axis. For single- axis analytical solution is possible and the switching line passing through the state-space origin belongs to parabolic. For multi-axis, it is impossible to get analytical solution due to the dynamic coupling between the axes and must be solved numerically. Proved by modern research, Euler axis rotations are quasi-time-optimal in general. On the basis of minimum value principles, a research for reorienting an inertial syrnmetric spacecraft with time cost function from an initial state of rest to a final state of rest is deduced. And the solution to it is stated below: Firstly, the essential condition for solving the problem is deduced with the minimum value principle. The necessary conditions for optimality yield a two point boundary-value problem (TPBVP), which, when solved, produces the control history that minimize time performance index. In the nonsingular control, the solution is the' bang-bang maneuver. The control profile is characterized by Saturated controls for the entire maneuver. The singular control maybe existed. It is only singular in mathematics. According to physical principle, the bigger the mode of the control torque is, the shorter the time is. So saturated controls are used in singular control. Secondly, the control parameters are always in maximum, so the key problem is to determine switch point thus original problem is changed to find the changing time. By the use of adjusting the switch on/off time, the genetic algorithm, which is a new robust method is optimized to determine the switch features without the gyroscopic coupling. There is improvement upon the traditional GA in this research. The homotopy method to find the nonlinear algebra is based on rigorous topology continuum theory. Based on the idea of the homotopy, the relaxation parameters are introduced, and the switch point is figured out with simulated annealing. Computer simulation results using a rigid body show that the new method is feasible and efficient. A practical method of computing approximate solutions to the time-optimal control- switch times for rigid body reorientation has been developed.

Vibration control of uncertain multiple launch rocket system using radial basis function neural network

NASA Astrophysics Data System (ADS)

Li, Bo; Rui, Xiaoting

2018-01-01

Poor dispersion characteristics of rockets due to the vibration of Multiple Launch Rocket System (MLRS) have always restricted the MLRS development for several decades. Vibration control is a key technique to improve the dispersion characteristics of rockets. For a mechanical system such as MLRS, the major difficulty in designing an appropriate control strategy that can achieve the desired vibration control performance is to guarantee the robustness and stability of the control system under the occurrence of uncertainties and nonlinearities. To approach this problem, a computed torque controller integrated with a radial basis function neural network is proposed to achieve the high-precision vibration control for MLRS. In this paper, the vibration response of a computed torque controlled MLRS is described. The azimuth and elevation mechanisms of the MLRS are driven by permanent magnet synchronous motors and supposed to be rigid. First, the dynamic model of motor-mechanism coupling system is established using Lagrange method and field-oriented control theory. Then, in order to deal with the nonlinearities, a computed torque controller is designed to control the vibration of the MLRS when it is firing a salvo of rockets. Furthermore, to compensate for the lumped uncertainty due to parametric variations and un-modeled dynamics in the design of the computed torque controller, a radial basis function neural network estimator is developed to adapt the uncertainty based on Lyapunov stability theory. Finally, the simulated results demonstrate the effectiveness of the proposed control system and show that the proposed controller is robust with regard to the uncertainty.

Medical-Grade Channel Access and Admission Control in 802.11e EDCA for Healthcare Applications

PubMed Central

Son, Sunghwa; Park, Kyung-Joon; Park, Eun-Chan

2016-01-01

In this paper, we deal with the problem of assuring medical-grade quality of service (QoS) for real-time medical applications in wireless healthcare systems based on IEEE 802.11e. Firstly, we show that the differentiated channel access of IEEE 802.11e cannot effectively assure medical-grade QoS because of priority inversion. To resolve this problem, we propose an efficient channel access algorithm. The proposed algorithm adjusts arbitrary inter-frame space (AIFS) in the IEEE 802.11e protocol depending on the QoS measurement of medical traffic, to provide differentiated near-absolute priority for medical traffic. In addition, based on rigorous capacity analysis, we propose an admission control scheme that can avoid performance degradation due to network overload. Via extensive simulations, we show that the proposed mechanism strictly assures the medical-grade QoS and improves the throughput of low-priority traffic by more than several times compared to the conventional IEEE 802.11e. PMID:27490666

Multi-Agent Cooperative Target Search

PubMed Central

Hu, Jinwen; Xie, Lihua; Xu, Jun; Xu, Zhao

2014-01-01

This paper addresses a vision-based cooperative search for multiple mobile ground targets by a group of unmanned aerial vehicles (UAVs) with limited sensing and communication capabilities. The airborne camera on each UAV has a limited field of view and its target discriminability varies as a function of altitude. First, by dividing the whole surveillance region into cells, a probability map can be formed for each UAV indicating the probability of target existence within each cell. Then, we propose a distributed probability map updating model which includes the fusion of measurement information, information sharing among neighboring agents, information decay and transmission due to environmental changes such as the target movement. Furthermore, we formulate the target search problem as a multi-agent cooperative coverage control problem by optimizing the collective coverage area and the detection performance. The proposed map updating model and the cooperative control scheme are distributed, i.e., assuming that each agent only communicates with its neighbors within its communication range. Finally, the effectiveness of the proposed algorithms is illustrated by simulation. PMID:24865884

Vortex/Flame Interactions in Microgravity Pulsed Jet Diffusion Flames

NASA Technical Reports Server (NTRS)

Bahadori, M. Y.; Hegde, U.; Stocker, D. P.

1999-01-01

The problem of vortex/flame interaction is of fundamental importance to turbulent combustion. These interactions have been studied in normal gravity. It was found that due to the interactions between the imposed disturbances and buoyancy induced instabilities, several overall length scales dominated the flame. The problem of multiple scales does not exist in microgravity for a pulsed laminar flame, since there are no buoyancy induced instabilities. The absence of buoyant convection therefore provides an environment to study the role of vortices interacting with flames in a controlled manner. There are strong similarities between imposed and naturally occurring perturbations, since both can be described by the same spatial instability theory. Hence, imposing a harmonic disturbance on a microgravity laminar flame creates effects similar to those occurring naturally in transitional/turbulent diffusion flames observed in microgravity. In this study, controlled, large-scale, axisymmetric vortices are imposed on a microgravity laminar diffusion flame. The experimental results and predictions from a numerical model of transient jet diffusion flames are presented and the characteristics of pulsed flame are described.

Adaptive Filter Design Using Type-2 Fuzzy Cerebellar Model Articulation Controller.

PubMed

Lin, Chih-Min; Yang, Ming-Shu; Chao, Fei; Hu, Xiao-Min; Zhang, Jun

2016-10-01

This paper aims to propose an efficient network and applies it as an adaptive filter for the signal processing problems. An adaptive filter is proposed using a novel interval type-2 fuzzy cerebellar model articulation controller (T2FCMAC). The T2FCMAC realizes an interval type-2 fuzzy logic system based on the structure of the CMAC. Due to the better ability of handling uncertainties, type-2 fuzzy sets can solve some complicated problems with outstanding effectiveness than type-1 fuzzy sets. In addition, the Lyapunov function is utilized to derive the conditions of the adaptive learning rates, so that the convergence of the filtering error can be guaranteed. In order to demonstrate the performance of the proposed adaptive T2FCMAC filter, it is tested in signal processing applications, including a nonlinear channel equalization system, a time-varying channel equalization system, and an adaptive noise cancellation system. The advantages of the proposed filter over the other adaptive filters are verified through simulations.

Remote Operations of the Deep Space Network Radio Science Subsystem

NASA Astrophysics Data System (ADS)

Caetta, J.; Asmar, S.; Abbate, S.; Connally, M.; Goltz, G.

1998-04-01

The capability for scientists to remotely control systems located at the Deep Space Network facilities only recently has been incorporated in the design and implementation of new equipment. However, time lines for the implementation, distribution, and operational readiness of such systems can extend much farther into the future than the users can wait. The Radio Science Systems Group was faced with just that circumstance; new hardware was not scheduled to become operational for several years, but the increasing number of experiments and configurations for Cassini, Galileo, Mars missions, and other flight projects made that time frame impractical because of the associated increasing risk of not acquiring critical data. Therefore, a method of interfacing with the current radio science subsystem has been developed and used with a high degree of success, although with occasional problems due to this capability not having been originally designed into the system. This article discusses both the method and the problems involved in integrating this new (remote) method of control with a legacy system.

Report on Project to Characterize Multi-Junction Solar Cells in the Stratosphere using Low-Cost Balloon and Communication Technologies

NASA Technical Reports Server (NTRS)

Mirza, Ali; Sant, David; Woodyard, James R.; Johnston, Richard R.; Brown, William J.

2002-01-01

Balloon, control and communication technologies are under development in our laboratory for testing multi-junction solar cells in the stratosphere to achieve near AM0 conditions. One flight, Suntracker I, has been carried out reported earlier. We report on our efforts in preparation for a second flight, Suntracker II, that was aborted due to hardware problems. The package for Suntracker I system has been modified to include separate electronics and battery packs for the 70 centimeter and 2 meter systems. The collimator control system and motor gearboxes have been redesigned to address problems with the virtual stops and backlash. Surface mount technology on a printed circuit board was used in place of the through-hole prototype circuit in efforts to reduce weight and size, and improve reliability. A mobile base station has been constructed that includes a 35' tower with a two axis rotator and multi-element yagi antennas. Modifications in Suntracker I and the factors that lead to aborting Suntracker II are discussed.

Optimal placement of FACTS devices using optimization techniques: A review

NASA Astrophysics Data System (ADS)

Gaur, Dipesh; Mathew, Lini

2018-03-01

Modern power system is dealt with overloading problem especially transmission network which works on their maximum limit. Today’s power system network tends to become unstable and prone to collapse due to disturbances. Flexible AC Transmission system (FACTS) provides solution to problems like line overloading, voltage stability, losses, power flow etc. FACTS can play important role in improving static and dynamic performance of power system. FACTS devices need high initial investment. Therefore, FACTS location, type and their rating are vital and should be optimized to place in the network for maximum benefit. In this paper, different optimization methods like Particle Swarm Optimization (PSO), Genetic Algorithm (GA) etc. are discussed and compared for optimal location, type and rating of devices. FACTS devices such as Thyristor Controlled Series Compensator (TCSC), Static Var Compensator (SVC) and Static Synchronous Compensator (STATCOM) are considered here. Mentioned FACTS controllers effects on different IEEE bus network parameters like generation cost, active power loss, voltage stability etc. have been analyzed and compared among the devices.

Modeling of Lunar Dust Contamination Due to Plume Impingement

NASA Technical Reports Server (NTRS)

Woronowicz, Michael

2009-01-01

During the Apollo missions it became apparent that lunar dust was a significant hazard. Problems included: surface obscuration during landing sequence; abrasion damage to gouge faces and helmet visors; mechanism clogging; development of space suit pressurization leaks; loss of radiator heat rejection capabilities to the point where vulnerable equipment exceeded maximum survival temperature ratings; temporary vision and respiratory problems within the Apollo Lunar Module (LM). NASA Constellation Program features many system-level components, including the Altair Lunar Lander. Altair to endure longer periods at lunar surface conditions: Apollo LM, about three days; Altair, over seven months. Program managers interested in plume-generated dust transport onto thermal control surface radiators of the first Altair created by its own landing operations.

Generalization of Water Pricing Model in Agriculture and Domestic Groundwater for Water Sustainability and Conservation

NASA Astrophysics Data System (ADS)

Hek, Tan Kim; Fadzli Ramli, Mohammad; Iryanto; Rohana Goh, Siti; Zaki, Mohd Faiz M.

2018-03-01

The water requirement greatly increased due to population growth, increased agricultural areas and industrial development, thus causing high water demand. The complex problems facing by country is water pricing is not designed optimally as a staple of human needs and on the other hand also cannot guarantee the maintenance and distribution of water effectively. The cheap water pricing caused increase of water use and unmanageable water resource. Therefore, the more optimal water pricing as an effective control of water policy is needed for the sake of ensuring water resources conservation and sustainability. This paper presents the review on problems, issues and mathematical modelling of water pricing based on agriculture and domestic groundwater for water sustainability and conservation.

Imagining intergroup contact can combat mental health stigma by reducing anxiety, avoidance and negative stereotyping.

PubMed

Stathi, Sofia; Tsantila, Katerina; Crisp, Richard J

2012-01-01

Research has demonstrated widespread negative attitudes held toward people with mental health problems. Our study investigated whether a new prejudice reduction technique, imagined intergroup contact (Crisp & Turner, 2009), could combat stigma against people with mental illness, and the mediating processes through which it may exert this beneficial effect. We found that compared to a control condition, participants who imagined a positive encounter with a schizophrenic person reported weakened stereotypes and formed stronger intentions to engage in future social interactions with schizophrenic people in general. Importantly, these intentions were formed due to reduced feelings of anxiety about future interactions. We discuss the implications of these findings for improving the social inclusion of people with mental health problems.

Injury prevention and other international public health initiatives.

PubMed

Razzak, Junaid A; Sasser, Scott M; Kellermann, Arthur L

2005-02-01

Injuries, whether caused by unintentional or intentional events, area significant public health problem. The burden of injury is greatest in low-and middle-income countries and among individuals of low socioeconomic status living in high-income countries. Most of these injuries are prevent-able. Emergency physicians can play an important role in reducing the global burden of injuries by providing expert care and by identifying, implementing, and evaluating population-based countermeasures to prevent and control injuries. The strategy used in a particular country depends in large part on the nature of the local problem, the concerns of the population, the availability of resources, and competing demands. Even simple countermeasures may have a big impact in reducing the global burden of death and disability due to injury.

Work-focused cognitive behavioral intervention for psychological complaints in patients on sick leave due to work-related stress: Results from a randomized controlled trial.

PubMed

Dalgaard, Vita Ligaya; Andersen, Lars Peter Sønderbo; Andersen, Johan Hviid; Willert, Morten Vejs; Carstensen, Ole; Glasscock, David John

2017-08-22

Work-related stress is a global problem with negative implications for individuals and society. The purpose of the current study was to evaluate a stress management intervention for patients on sick leave due to work-related stress complaints using a three-armed randomized controlled design. Participants were patients referred from three municipalities to the regional Department of Occupational Medicine. Inclusion criteria were: 1) sick leave due to work-related stress complaints, 2) a diagnosis of adjustment disorder or reactions to severe stress (ICD 10 code: F43,2 - F 43,9 not PTSD) or mild depressive episode (F 32.0). Through a double randomization procedure patients (n = 163) were randomized to either an intervention group (n = 58), a 'control group A' receiving a clinical examination (n = 56), or 'control group B' (n = 49) receiving no offers at the department. The intervention comprised six sessions of individual cognitive behavioral therapy and the offer of a small workplace intervention. Questionnaire data were analyzed with multivariate repeated measurements analysis. Primary outcomes assessed were perceived stress and general mental health. Secondary outcomes were sleep quality and cognitive failures. Follow-up was at four and 10 months after baseline. Complaints were significantly reduced in all groups over time. No group effects were observed between the intervention group and control group A that was clinically assessed. Significant group effects were found for perceived stress and memory when comparing the intervention group to group B, but most likely not due to an intervention effect. Psychological complaints improved substantially over time in all groups, but there was no significant treatment effect on any outcomes when the intervention group was compared to control group A that received a clinical assessment. ISRCTN ISRCTN91404229. Registered 03 August 2012 (retrospectively registered).

Robot formation control in stealth mode with scalable team size

NASA Astrophysics Data System (ADS)

Yu, Hongjun; Shi, Peng; Lim, Cheng-Chew

2016-11-01

In situations where robots need to keep electromagnetic silent in a formation, communication channels become unavailable. Moreover, as passive displacement sensors are used, limited sensing ranges are inevitable due to power insufficiency and limited noise reduction. To address the formation control problem for a scalable team of robots subject to the above restrictions, a flexible strategy is necessary. In this paper, under the assumption that the data transmission among the robots is not available, a novel controller and a protocol are designed that do not rely on communication. As the controller only drives the robots to a partially desired formation, a distributed coordination protocol is proposed to resolve the imperfections. It is shown that the effectiveness of the controller and the protocol rely on the formation connectivity, and a condition is given on the sensing range. Simulations are conducted to illustrate the feasibility and advantages of the new design scheme developed.

Optical fiber sensors and signal processing for intelligent structure monitoring

NASA Technical Reports Server (NTRS)

Rogowski, Robert; Claus, R. O.; Lindner, D. K.; Thomas, Daniel; Cox, Dave

1988-01-01

The analytic and experimental performance of optical fiber sensors for the control of vibration of large aerospace and other structures are investigated. In particular, model domain optical fiber sensor systems, are being studied due to their apparent potential as distributed, low mass sensors of vibration over appropriate ranges of both low frequency and low amplitude displacements. Progress during the past three months is outlined. Progress since September is divided into work in the areas of experimental hardware development, analytical analysis, control design and sensor development. During the next six months, tests of a prototype closed-loop control system for a beam are planned which will demonstrate the solution of several optical fiber instrumentation device problems, the performance of the control system theory which incorporates the model of the modal domain sensor, and the potential for distributed control which this sensor approach offers.

Jerk Minimization Method for Vibration Control in Buildings

NASA Technical Reports Server (NTRS)

Abatan, Ayo O.; Yao, Leummim

1997-01-01

In many vibration minimization control problems for high rise buildings subject to strong earthquake loads, the emphasis has been on a combination of minimizing the displacement, the velocity and the acceleration of the motion of the building. In most cases, the accelerations that are involved are not necessarily large but the change in them (jerk) are abrupt. These changes in magnitude or direction are responsible for most building damage and also create discomfort like motion sickness for inhabitants of these structures because of the element of surprise. We propose a method of minimizing also the jerk which is the sudden change in acceleration or the derivative of the acceleration using classical linear quadratic optimal controls. This was done through the introduction of a quadratic performance index involving the cost due to the jerk; a special change of variable; and using the jerk as a control variable. The values of the optimal control are obtained using the Riccati equation.

A Direct Adaptive Control Approach in the Presence of Model Mismatch

NASA Technical Reports Server (NTRS)

Joshi, Suresh M.; Tao, Gang; Khong, Thuan

2009-01-01

This paper considers the problem of direct model reference adaptive control when the plant-model matching conditions are violated due to abnormal changes in the plant or incorrect knowledge of the plant's mathematical structure. The approach consists of direct adaptation of state feedback gains for state tracking, and simultaneous estimation of the plant-model mismatch. Because of the mismatch, the plant can no longer track the state of the original reference model, but may be able to track a new reference model that still provides satisfactory performance. The reference model is updated if the estimated plant-model mismatch exceeds a bound that is determined via robust stability and/or performance criteria. The resulting controller is a hybrid direct-indirect adaptive controller that offers asymptotic state tracking in the presence of plant-model mismatch as well as parameter deviations.

SORPTION OF ARSENATE AND ARSENITE ON RUO2·XH2O: ANALYSIS OF SORBED PHASE OXIDATION STATE BY XANES

EPA Science Inventory

Arsenic contamination in water, soil and sediment is a global problem. Awareness of the problems created by As contamination have increased in recent years due to reports from Asia describing immense health problems due to As in drinking water [1, 2]. Changes in the U.S. regulati...

Manufacturing DTaP-based combination vaccines: industrial challenges around essential public health tools.

PubMed

Vidor, Emmanuel; Soubeyrand, Benoit

2016-12-01

The manufacture of DTP-backboned combination vaccines is complex, and vaccine quality is evaluated by both batch composition and conformance of manufacturing history. Since their first availability, both the manufacturing regulations for DTP combination vaccines and their demand have evolved significantly. This has resulted in a constant need to modify manufacturing and quality control processes. Areas covered: Regulations that govern the manufacture of complex vaccines can be inconsistent between countries and need to be aligned with the regulatory requirements that apply in all countries of distribution. Changes in product mix and quantities can lead to uncertainty in vaccine supply maintenance. These problems are discussed in the context of the importance of these products as essential public health tools. Expert commentary: Increasing demand for complex vaccines globally has led to problems in supply due to intrinsically complex manufacturing and regulatory procedures. Vaccine manufacturers are fully engaged in the resolution of these challenges, but currently changes in demand need ideally to be anticipated approximately 3 years in advance due to long production cycle times.

Cause and effect: the linkage between the health information seeking behavior and the online environment--a review.

PubMed

Bratucu, R; Gheorghe, I R; Purcarea, R M; Gheorghe, C M; Popa Velea, O; Purcarea, V L

2014-09-15

Today, health care consumers are taking more control over their health care problems, investing more time in finding and getting information as well as looking for proper methods in order to investigate more closely the health care information received from their physicians. Unfortunately, in health care consumers' views, the trustworthiness of health authorities and institutions has declined in the last years. So, consumers have found a new solution to their health problems, that is, the Internet. Recently, studies revealed that consumers seeking for health information have more options to look for data in comparison to the methods used a few years ago. Therefore, due to the available technology, consumers have more outlets to search for information. For instance, the Internet is a source that has revolutionized the way consumers seek data due its customized methods of assessing both quantitative and qualitative information which may be achieved with minimal effort and low costs, offering at the same time, several advantages such as making the decision process more efficient.

Effects of game-based virtual reality on health-related quality of life in chronic stroke patients: A randomized, controlled study.

PubMed

Shin, Joon-Ho; Bog Park, Si; Ho Jang, Seong

2015-08-01

In the present study, we aimed to determine whether game-based virtual reality (VR) rehabilitation, combined with occupational therapy (OT), could improve health-related quality of life, depression, and upper extremity function. We recruited 35 patients with chronic hemiparetic stroke, and these participants were randomized into groups that underwent VR rehabilitation plus conventional OT, or the same amount of conventional OT alone, for 20 sessions over 4 weeks. Compared to baseline, the VR rehabilitation plus OT group exhibited significantly improved role limitation due to emotional problems (p=0.047). Compared to baseline, both groups also exhibited significantly improved depression (p=0.017) and upper extremity function (p=0.001), although the inter-group differences were not significant. However, a significant inter-group difference was observed for role limitation due to physical problems (p=0.031). Our results indicate that game-based VR rehabilitation has specific effects on health-related quality of life, depression, and upper extremity function among patients with chronic hemiparetic stroke. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cause and effect: the linkage between the health information seeking behavior and the online environment- a review

PubMed Central

Bratucu, R; Gheorghe, IR; Purcarea, RM; Gheorghe, CM; Popa Velea, O; Purcarea, VL

2014-01-01

Abstract Today, health care consumers are taking more control over their health care problems, investing more time in finding and getting information as well as looking for proper methods in order to investigate more closely the health care information received from their physicians. Unfortunately, in health care consumers’ views, the trustworthiness of health authorities and institutions has declined in the last years. So, consumers have found a new solution to their health problems, that is, the Internet. Recently, studies revealed that consumers seeking for health information have more options to look for data in comparison to the methods used a few years ago. Therefore, due to the available technology, consumers have more outlets to search for information. For instance, the Internet is a source that has revolutionized the way consumers seek data due its customized methods of assessing both quantitative and qualitative information which may be achieved with minimal effort and low costs, offering at the same time, several advantages such as making the decision process more efficient. PMID:25408746

Previously undiagnosed attention-deficit/hyperactivity disorder associated with poor metabolic control in adolescents with type 1 diabetes.

PubMed

Nylander, C; Lindström, K; Khalifa, N; Fernell, E

2018-06-01

Managing modern diabetes treatment requires efficient executive functions. Patients with attention-deficit/hyperactivity disorder (ADHD) and type 1 diabetes have poor metabolic control and present with ketoacidosis more often than patients without ADHD. To assess whether patients with type 1 diabetes and with indications of executive problems met criteria for ADHD, and to investigate whether these patients had difficulties achieving metabolic control. In a hospital-based study, including 3 pediatric departments at hospitals in Stockholm and Uppsala, Sweden, questionnaires regarding executive problems had been filled out by 12- to 18-year-old patients with type 1 diabetes and their parents. Out of 166 patients with completed questionnaires, 49 were selected for a clinical study due to reported executive problems/ADHD symptoms. However, 7 already had a diagnosis of ADHD, 21 denied follow-up, 8 did not respond, leaving 13 adolescents for the clinical assessment. Of the clinically assessed adolescents, 9 (6 girls) met criteria for ADHD. Patients who did not respond to the follow-up and patients who were diagnosed with ADHD within the study, showed to a larger extent than the other study groups high HbA1c levels (>70 mmol/mol, 8,6%). HbA1c >70 mmol/mol (8.6%) was associated with diagnosed ADHD (prior to or within the study), odds ratio 2.96 (95% confidence interval 1.02-8.60). Patients with type 1 diabetes and poor metabolic control should be assessed with regard to ADHD. There is a need for paying special attention to girls with poor metabolic control. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Attachment and family functioning in patients with internet addiction.

PubMed

Şenormancı, Ömer; Şenormancı, Güliz; Güçlü, Oya; Konkan, Ramazan

2014-01-01

Although the Internet is used effectively in many areas of life, some users experience problems because of over-use due to a lack of control. The diagnostic criteria for Internet addiction include disruptions in family relationships, but adequate data on the attachment styles and family functioning associated with this condition are limited. This study aimed to investigate the attachment styles and family functioning of patients with Internet addiction. The sample included 30 male patients consecutively admitted to the Bakırköy Mental Health and Research Hospital Internet Addiction Outpatient Clinic, who were diagnosed in clinical interviews as having Internet addiction according to Young's (1998) criteria. Thirty healthy males who were matched with the experimental group in terms of sociodemographic characteristics were included as control subjects. Both groups provided sociodemographic data and completed the Beck Depression Inventory (BDI), the Experiences in Close Relationships Questionnaire-r (ECR-r) and the Family Assessment Device (FAD). Patients with Internet addiction had higher BDI scores (P<.001) and higher attachment anxiety subscores on ECR-r (P<.001) compared with those in the control group. Patients with Internet addiction evaluated their family functioning as more negative and reported problems in every aspect addressed by the FAD. Scores on the FAD behaviour control, affective responsiveness, and problem-solving subscales (P<.05) and on the FAD communication, roles, and general functioning subscales (P<.001) were significantly higher in the patient compared with the control group. Patients with Internet addiction have more anxious attachment styles as well as prominent disruptions in family functioning. Thus, it may be important to evaluate the attachment styles and family functioning of patients with Internet addiction. Indeed, comprehensive treatment approaches including other family members may make important contributions to treatment success. Copyright © 2014 Elsevier Inc. All rights reserved.

Optimization and Control of Agent-Based Models in Biology: A Perspective.

PubMed

An, G; Fitzpatrick, B G; Christley, S; Federico, P; Kanarek, A; Neilan, R Miller; Oremland, M; Salinas, R; Laubenbacher, R; Lenhart, S

2017-01-01

Agent-based models (ABMs) have become an increasingly important mode of inquiry for the life sciences. They are particularly valuable for systems that are not understood well enough to build an equation-based model. These advantages, however, are counterbalanced by the difficulty of analyzing and using ABMs, due to the lack of the type of mathematical tools available for more traditional models, which leaves simulation as the primary approach. As models become large, simulation becomes challenging. This paper proposes a novel approach to two mathematical aspects of ABMs, optimization and control, and it presents a few first steps outlining how one might carry out this approach. Rather than viewing the ABM as a model, it is to be viewed as a surrogate for the actual system. For a given optimization or control problem (which may change over time), the surrogate system is modeled instead, using data from the ABM and a modeling framework for which ready-made mathematical tools exist, such as differential equations, or for which control strategies can explored more easily. Once the optimization problem is solved for the model of the surrogate, it is then lifted to the surrogate and tested. The final step is to lift the optimization solution from the surrogate system to the actual system. This program is illustrated with published work, using two relatively simple ABMs as a demonstration, Sugarscape and a consumer-resource ABM. Specific techniques discussed include dimension reduction and approximation of an ABM by difference equations as well systems of PDEs, related to certain specific control objectives. This demonstration illustrates the very challenging mathematical problems that need to be solved before this approach can be realistically applied to complex and large ABMs, current and future. The paper outlines a research program to address them.

Establishment and evaluation of a theater influenza monitoring platform.

PubMed

Wang, Jian; Yang, Hui-Suo; Deng, Bing; Shi, Meng-Jing; Li, Xiang-Da; Nian, Qing-Gong; Song, Wen-Jing; Bing, Feng; Li, Qing-Feng

2017-11-20

Influenza is an acute respiratory infectious disease with a high incidence rate in the Chinese army, which directly disturbs military training and affects soldiers' health. Influenza surveillance systems are widely used around the world and play an important role in influenza epidemic prevention and control. As a theater centers for disease prevention and control, we established an influenza monitoring platform (IMP) in 2014 to strengthen the monitoring of influenza-like illness and influenza virus infection. In this study, we introduced the constitution, influenza virus detection, and quality control for an IMP. The monitoring effect was also evaluated by comparing the monitoring data with data from national influenza surveillance systems. The experiences and problems associated with the platform also were summarized. A theater IMP was established based on 3 levels of medical units, including monitoring sites, testing laboratories and a checking laboratory. A series of measures were taken to guarantee the quality of monitoring, such as technical training, a unified process, sufficient supervision and timely communication. The platform has run smoothly for 3 monitoring years to date. In the 2014-2015 and 2016-2017 monitoring years, sample amount coincided with that obtained from the National Influenza Surveillance program. In the 2015-2016 monitoring year, due to the strict prevention and control measures, an influenza epidemic peak was avoided in monitoring units, and the monitoring data did not coincide with that of the National Influenza Surveillance program. Several problems, including insufficient attention, unreasonable administrative intervention or subordination relationships, and the necessity of detection in monitoring sites were still observed. A theater IMP was established rationally and played a deserved role in the prevention and control of influenza. However, several problems remain to be solved.

Using ‘appreciative inquiry’ in India to improve infection control practices in maternity care: a qualitative study

PubMed Central

Sharma, Bharati; Ramani, K.V.; Mavalankar, Dileep; Kanguru, Lovney; Hussein, Julia

2015-01-01

Background Infections acquired during childbirth are a common cause of maternal and perinatal mortality and morbidity. Changing provider behaviour and organisational settings within the health system is key to reducing the spread of infection. Objective To explore the opinions of health personnel on health system factors related to infection control and their perceptions of change in a sample of hospital maternity units. Design An organisational change process called ‘appreciative inquiry’ (AI) was introduced in three maternity units of hospitals in Gujarat, India. AI is a change process that builds on recognition of positive actions, behaviours, and attitudes. In-depth interviews were conducted with health personnel to elicit information on the environment within which they work, including physical and organisational factors, motivation, awareness, practices, perceptions of their role, and other health system factors related to infection control activities. Data were obtained from three hospitals which implemented AI and another three not involved in the intervention. Results Challenges which emerged included management processes (e.g. decision-making and problem-solving modalities), human resource shortages, and physical infrastructure (e.g. space, water, and electricity supplies). AI was perceived as having a positive influence on infection control practices. Respondents also said that management processes improved although some hospitals had already undergone an accreditation process which could have influenced the changes described. Participants reported that team relationships had been strengthened due to AI. Conclusion Technical knowledge is often emphasised in health care settings and less attention is paid to factors such as team relationships, leadership, and problem solving. AI can contribute to improving infection control by catalysing and creating forums for team building, shared decision making and problem solving in an enabling environment. PMID:26119249

Using 'appreciative inquiry' in India to improve infection control practices in maternity care: a qualitative study.

PubMed

Sharma, Bharati; Ramani, K V; Mavalankar, Dileep; Kanguru, Lovney; Hussein, Julia

2015-01-01

Infections acquired during childbirth are a common cause of maternal and perinatal mortality and morbidity. Changing provider behaviour and organisational settings within the health system is key to reducing the spread of infection. To explore the opinions of health personnel on health system factors related to infection control and their perceptions of change in a sample of hospital maternity units. An organisational change process called 'appreciative inquiry' (AI) was introduced in three maternity units of hospitals in Gujarat, India. AI is a change process that builds on recognition of positive actions, behaviours, and attitudes. In-depth interviews were conducted with health personnel to elicit information on the environment within which they work, including physical and organisational factors, motivation, awareness, practices, perceptions of their role, and other health system factors related to infection control activities. Data were obtained from three hospitals which implemented AI and another three not involved in the intervention. Challenges which emerged included management processes (e.g. decision-making and problem-solving modalities), human resource shortages, and physical infrastructure (e.g. space, water, and electricity supplies). AI was perceived as having a positive influence on infection control practices. Respondents also said that management processes improved although some hospitals had already undergone an accreditation process which could have influenced the changes described. Participants reported that team relationships had been strengthened due to AI. Technical knowledge is often emphasised in health care settings and less attention is paid to factors such as team relationships, leadership, and problem solving. AI can contribute to improving infection control by catalysing and creating forums for team building, shared decision making and problem solving in an enabling environment.

Optimal lunar soft landing trajectories using taboo evolutionary programming

NASA Astrophysics Data System (ADS)

Mutyalarao, M.; Raj, M. Xavier James

A safe lunar landing is a key factor to undertake an effective lunar exploration. Lunar lander consists of four phases such as launch phase, the earth-moon transfer phase, circumlunar phase and landing phase. The landing phase can be either hard landing or soft landing. Hard landing means the vehicle lands under the influence of gravity without any deceleration measures. However, soft landing reduces the vertical velocity of the vehicle before landing. Therefore, for the safety of the astronauts as well as the vehicle lunar soft landing with an acceptable velocity is very much essential. So it is important to design the optimal lunar soft landing trajectory with minimum fuel consumption. Optimization of Lunar Soft landing is a complex optimal control problem. In this paper, an analysis related to lunar soft landing from a parking orbit around Moon has been carried out. A two-dimensional trajectory optimization problem is attempted. The problem is complex due to the presence of system constraints. To solve the time-history of control parameters, the problem is converted into two point boundary value problem by using the maximum principle of Pontrygen. Taboo Evolutionary Programming (TEP) technique is a stochastic method developed in recent years and successfully implemented in several fields of research. It combines the features of taboo search and single-point mutation evolutionary programming. Identifying the best unknown parameters of the problem under consideration is the central idea for many space trajectory optimization problems. The TEP technique is used in the present methodology for the best estimation of initial unknown parameters by minimizing objective function interms of fuel requirements. The optimal estimation subsequently results into an optimal trajectory design of a module for soft landing on the Moon from a lunar parking orbit. Numerical simulations demonstrate that the proposed approach is highly efficient and it reduces the minimum fuel consumption. The results are compared with the available results in literature shows that the solution of present algorithm is better than some of the existing algorithms. Keywords: soft landing, trajectory optimization, evolutionary programming, control parameters, Pontrygen principle.

Load Frequency Control by use of a Number of Both Heat Pump Water Heaters and Electric Vehicles in Power System with a Large Integration of Renewable Energy Sources

NASA Astrophysics Data System (ADS)

Masuta, Taisuke; Shimizu, Koichiro; Yokoyama, Akihiko

In Japan, from the viewpoints of global warming countermeasures and energy security, it is expected to establish a smart grid as a power system into which a large amount of generation from renewable energy sources such as wind power generation and photovoltaic generation can be installed. Measures for the power system stability and reliability are necessary because a large integration of these renewable energy sources causes some problems in power systems, e.g. frequency fluctuation and distribution voltage rise, and Battery Energy Storage System (BESS) is one of effective solutions to these problems. Due to a high cost of the BESS, our research group has studied an application of controllable loads such as Heat Pump Water Heater (HPWH) and Electric Vehicle (EV) to the power system control for reduction of the required capacity of BESS. This paper proposes a new coordinated Load Frequency Control (LFC) method for the conventional power plants, the BESS, the HPWHs, and the EVs. The performance of the proposed LFC method is evaluated by the numerical simulations conducted on a power system model with a large integration of wind power generation and photovoltaic generation.

Fusing terrain and goals: agent control in urban environments

NASA Astrophysics Data System (ADS)

Kaptan, Varol; Gelenbe, Erol

2006-04-01

The changing face of contemporary military conflicts has forced a major shift of focus in tactical planning and evaluation from the classical Cold War battlefield to an asymmetric guerrilla-type warfare in densely populated urban areas. The new arena of conflict presents unique operational difficulties due to factors like complex mobility restrictions and the necessity to preserve civilian lives and infrastructure. In this paper we present a novel method for autonomous agent control in an urban environment. Our approach is based on fusing terrain information and agent goals for the purpose of transforming the problem of navigation in a complex environment with many obstacles into the easier problem of navigation in a virtual obstacle-free space. The main advantage of our approach is its ability to act as an adapter layer for a number of efficient agent control techniques which normally show poor performance when applied to an environment with many complex obstacles. Because of the very low computational and space complexity at runtime, our method is also particularly well suited for simulation or control of a huge number of agents (military as well as civilian) in a complex urban environment where traditional path-planning may be too expensive or where a just-in-time decision with hard real-time constraints is required.

Comparison of Feature Selection Techniques in Machine Learning for Anatomical Brain MRI in Dementia.

PubMed

Tohka, Jussi; Moradi, Elaheh; Huttunen, Heikki

2016-07-01

We present a comparative split-half resampling analysis of various data driven feature selection and classification methods for the whole brain voxel-based classification analysis of anatomical magnetic resonance images. We compared support vector machines (SVMs), with or without filter based feature selection, several embedded feature selection methods and stability selection. While comparisons of the accuracy of various classification methods have been reported previously, the variability of the out-of-training sample classification accuracy and the set of selected features due to independent training and test sets have not been previously addressed in a brain imaging context. We studied two classification problems: 1) Alzheimer's disease (AD) vs. normal control (NC) and 2) mild cognitive impairment (MCI) vs. NC classification. In AD vs. NC classification, the variability in the test accuracy due to the subject sample did not vary between different methods and exceeded the variability due to different classifiers. In MCI vs. NC classification, particularly with a large training set, embedded feature selection methods outperformed SVM-based ones with the difference in the test accuracy exceeding the test accuracy variability due to the subject sample. The filter and embedded methods produced divergent feature patterns for MCI vs. NC classification that suggests the utility of the embedded feature selection for this problem when linked with the good generalization performance. The stability of the feature sets was strongly correlated with the number of features selected, weakly correlated with the stability of classification accuracy, and uncorrelated with the average classification accuracy.

Optimization-based power management of hybrid power systems with applications in advanced hybrid electric vehicles and wind farms with battery storage

NASA Astrophysics Data System (ADS)

Borhan, Hoseinali

Modern hybrid electric vehicles and many stationary renewable power generation systems combine multiple power generating and energy storage devices to achieve an overall system-level efficiency and flexibility which is higher than their individual components. The power or energy management control, "brain" of these "hybrid" systems, determines adaptively and based on the power demand the power split between multiple subsystems and plays a critical role in overall system-level efficiency. This dissertation proposes that a receding horizon optimal control (aka Model Predictive Control) approach can be a natural and systematic framework for formulating this type of power management controls. More importantly the dissertation develops new results based on the classical theory of optimal control that allow solving the resulting optimal control problem in real-time, in spite of the complexities that arise due to several system nonlinearities and constraints. The dissertation focus is on two classes of hybrid systems: hybrid electric vehicles in the first part and wind farms with battery storage in the second part. The first part of the dissertation proposes and fully develops a real-time optimization-based power management strategy for hybrid electric vehicles. Current industry practice uses rule-based control techniques with "else-then-if" logic and look-up maps and tables in the power management of production hybrid vehicles. These algorithms are not guaranteed to result in the best possible fuel economy and there exists a gap between their performance and a minimum possible fuel economy benchmark. Furthermore, considerable time and effort are spent calibrating the control system in the vehicle development phase, and there is little flexibility in real-time handling of constraints and re-optimization of the system operation in the event of changing operating conditions and varying parameters. In addition, a proliferation of different powertrain configurations may result in the need for repeated control system redesign. To address these shortcomings, we formulate the power management problem as a nonlinear and constrained optimal control problem. Solution of this optimal control problem in real-time on chronometric- and memory-constrained automotive microcontrollers is quite challenging; this computational complexity is due to the highly nonlinear dynamics of the powertrain subsystems, mixed-integer switching modes of their operation, and time-varying and nonlinear hard constraints that system variables should satisfy. The main contribution of the first part of the dissertation is that it establishes methods for systematic and step-by step improvements in fuel economy while maintaining the algorithmic computational requirements in a real-time implementable framework. More specifically a linear time-varying model predictive control approach is employed first which uses sequential quadratic programming to find sub-optimal solutions to the power management problem. Next the objective function is further refined and broken into a short and a long horizon segments; the latter approximated as a function of the state using the connection between the Pontryagin minimum principle and Hamilton-Jacobi-Bellman equations. The power management problem is then solved using a nonlinear MPC framework with a dynamic programming solver and the fuel economy is further improved. Typical simplifying academic assumptions are minimal throughout this work, thanks to close collaboration with research scientists at Ford research labs and their stringent requirement that the proposed solutions be tested on high-fidelity production models. Simulation results on a high-fidelity model of a hybrid electric vehicle over multiple standard driving cycles reveal the potential for substantial fuel economy gains. To address the control calibration challenges, we also present a novel and fast calibration technique utilizing parallel computing techniques. ^ The second part of this dissertation presents an optimization-based control strategy for the power management of a wind farm with battery storage. The strategy seeks to minimize the error between the power delivered by the wind farm with battery storage and the power demand from an operator. In addition, the strategy attempts to maximize battery life. The control strategy has two main stages. The first stage produces a family of control solutions that minimize the power error subject to the battery constraints over an optimization horizon. These solutions are parameterized by a given value for the state of charge at the end of the optimization horizon. The second stage screens the family of control solutions to select one attaining an optimal balance between power error and battery life. The battery life model used in this stage is a weighted Amp-hour (Ah) throughput model. The control strategy is modular, allowing for more sophisticated optimization models in the first stage, or more elaborate battery life models in the second stage. The strategy is implemented in real-time in the framework of Model Predictive Control (MPC).

Due-Window Assignment Scheduling with Variable Job Processing Times

PubMed Central

Wu, Yu-Bin

2015-01-01

We consider a common due-window assignment scheduling problem jobs with variable job processing times on a single machine, where the processing time of a job is a function of its position in a sequence (i.e., learning effect) or its starting time (i.e., deteriorating effect). The problem is to determine the optimal due-windows, and the processing sequence simultaneously to minimize a cost function includes earliness, tardiness, the window location, window size, and weighted number of tardy jobs. We prove that the problem can be solved in polynomial time. PMID:25918745

An Investigation of the Effects of the Time Lag due to Long Transmission Distances Upon Remote Control. Phase 1; Tracking Experiments

NASA Technical Reports Server (NTRS)

Adams, James L.

1961-01-01

A series of pursuit tracking tasks were performed incorporating a transport lag in the control loop. The target was a mixture of four sine waves, the fastest having a frequency of 16 cycles per minute at full speed. An attempt was made to design the experiments so that they would provide data applicable to remote control of a ground vehicle over long transmission distances. Three programs were run. In each the time lag was placed between the control and the display. In the first program a velocity control was used and the operator was told that his knob controlled a vehicle, the problem represented a road 9 and he was to drive his vehicle along the road 9 using the delayed vehicle position as feedback for whatever means he desired. The objective was not to match the display traces. In the second program a velocity control was used, and the operator was told that the problem trace represented a road and the delayed trace represented a vehicle and he was to keep them together. The objective was to match display traces. The third program was identical with the first, except that an acceleration control was used rather than a velocity control. Target speeds used were full speed, 1/2 speed, 1/4 speed, 1/8 speed, and 1/16 speed. Time lags were 1/4 second, l/2 second, 1 second, 1-1/2 second, 2 second, 3 second, and 6 seconds. The experimental results are presented in the last section of this report.

Lac Qui Parle Flood Control Project Master Plan for Public Use Development and Resource Management.

DTIC Science & Technology

1980-08-01

the project area is the disposal of dead carp. Minnesota fishing regulations prohibit fishermen from returning rough fish to lakes or rivers after...in trash cans. Unless the dead fish are removed virtually daily, they begin to decompose and smell. Due to current work- force constraints, the Corps...is unable to remove the dead fish as often as it would like. No easy solution to this problem is apparent. 6.25 Potential for Future Development The

Recognition and treatment of neuropsychiatric disturbances in Parkinson's disease.

PubMed

Akbar, Umer; Friedman, Joseph H

2015-01-01

The non-motor symptoms of Parkinson's disease (PD) have been attracting increasing attention due to their ubiquitous nature and their often devastating effects on the quality of life. Behavioral problems in PD include dementia, depression, apathy, fatigue, anxiety, psychosis, akathisia, personality change, sleep disorders and impulse control disorders. Some of these are intrinsic to the neuropathology while others occur as an interplay between pathology, psychology and pharmacology. While few data exist for guiding therapy, enough is known to guide therapy in a rational manner.

Optimal control problem for linear fractional-order systems, described by equations with Hadamard-type derivative

NASA Astrophysics Data System (ADS)

Postnov, Sergey

2017-11-01

Two kinds of optimal control problem are investigated for linear time-invariant fractional-order systems with lumped parameters which dynamics described by equations with Hadamard-type derivative: the problem of control with minimal norm and the problem of control with minimal time at given restriction on control norm. The problem setting with nonlocal initial conditions studied. Admissible controls allowed to be the p-integrable functions (p > 1) at half-interval. The optimal control problem studied by moment method. The correctness and solvability conditions for the corresponding moment problem are derived. For several special cases the optimal control problems stated are solved analytically. Some analogies pointed for results obtained with the results which are known for integer-order systems and fractional-order systems describing by equations with Caputo- and Riemann-Liouville-type derivatives.

Optimal Control of Induction Machines to Minimize Transient Energy Losses

NASA Astrophysics Data System (ADS)

Plathottam, Siby Jose

Induction machines are electromechanical energy conversion devices comprised of a stator and a rotor. Torque is generated due to the interaction between the rotating magnetic field from the stator, and the current induced in the rotor conductors. Their speed and torque output can be precisely controlled by manipulating the magnitude, frequency, and phase of the three input sinusoidal voltage waveforms. Their ruggedness, low cost, and high efficiency have made them ubiquitous component of nearly every industrial application. Thus, even a small improvement in their energy efficient tend to give a large amount of electrical energy savings over the lifetime of the machine. Hence, increasing energy efficiency (reducing energy losses) in induction machines is a constrained optimization problem that has attracted attention from researchers. The energy conversion efficiency of induction machines depends on both the speed-torque operating point, as well as the input voltage waveform. It also depends on whether the machine is in the transient or steady state. Maximizing energy efficiency during steady state is a Static Optimization problem, that has been extensively studied, with commercial solutions available. On the other hand, improving energy efficiency during transients is a Dynamic Optimization problem that is sparsely studied. This dissertation exclusively focuses on improving energy efficiency during transients. This dissertation treats the transient energy loss minimization problem as an optimal control problem which consists of a dynamic model of the machine, and a cost functional. The rotor field oriented current fed model of the induction machine is selected as the dynamic model. The rotor speed and rotor d-axis flux are the state variables in the dynamic model. The stator currents referred to as d-and q-axis currents are the control inputs. A cost functional is proposed that assigns a cost to both the energy losses in the induction machine, as well as the deviations from desired speed-torque-magnetic flux setpoints. Using Pontryagin's minimum principle, a set of necessary conditions that must be satisfied by the optimal control trajectories are derived. The conditions are in the form a two-point boundary value problem, that can be solved numerically. The conjugate gradient method that was modified using the Hestenes-Stiefel formula was used to obtain the numerical solution of both the control and state trajectories. Using the distinctive shape of the numerical trajectories as inspiration, analytical expressions were derived for the state, and control trajectories. It was shown that the trajectory could be fully described by finding the solution of a one-dimensional optimization problem. The sensitivity of both the optimal trajectory and the optimal energy efficiency to different induction machine parameters were analyzed. A non-iterative solution that can use feedback for generating optimal control trajectories in real time was explored. It was found that an artificial neural network could be trained using the numerical solutions and made to emulate the optimal control trajectories with a high degree of accuracy. Hence a neural network along with a supervisory logic was implemented and used in a real-time simulation to control the Finite Element Method model of the induction machine. The results were compared with three other control regimes and the optimal control system was found to have the highest energy efficiency for the same drive cycle.

Respiratory tract infections in the immunocompromised.

PubMed

Godbole, Gauri; Gant, Vanya

2013-05-01

Pulmonary infections are particularly common in the immunosuppressed host. This review discusses emerging threats, newer modalities of diagnostic tests and emerging treatment options, and also highlights the increasing problem of antimicrobial resistance. Nosocomial pneumonia is increasingly due to multidrug-resistant Gram-negative organisms in immunosuppressed patients. Viral pneumonias remain a very significant threat, present atypically and carry a high mortality. Aspergillosis remains the most common fungal infection, and infections due to Mucorales are increasing. Multidrug-resistant tuberculosis is on the increase throughout the world. Mixed infections are common and early bronchoscopy with appropriate microbiological tests, including molecular diagnostics, optimise management and reduce mortality. Pulmonary infection remains the most frequent infectious complication in the immunocompromised host. These complex infections are often mixed, have atypical presentations and can be due to multidrug-resistant organisms. Multidisciplinary involvement in specialist centres with appropriate diagnostics, treatment and infection control improves outcome. There is a desperate need for new antimicrobial agents active against Gram-negative pathogens.

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

Oleinikov, A. I., E-mail: a.i.oleinikov@mail.ru; Bormotin, K. S., E-mail: cvmi@knastu.ru

It is shown that inverse problems of steady-state creep bending of plates in both the geometrically linear and nonlinear formulations can be represented in a variational formulation. Steady-state values of the obtained functionals corresponding to the solutions of the problems of inelastic deformation and springback are determined by applying a finite element procedure to the functionals. Optimal laws of creep deformation are formulated using the criterion of minimizing damage in the functionals of the inverse problems. The formulated problems are reduced to the problems solved by the finite element method using MSC.Marc software. Currently, forming of light metals poses tremendousmore » challenges due to their low ductility at room temperature and their unusual deformation characteristics at hot-cold work: strong asymmetry between tensile and compressive behavior, and a very pronounced anisotropy. We used the constitutive models of steady-state creep of initially transverse isotropy structural materials the kind of the stress state has influence. The paper gives basics of the developed computer-aided system of design, modeling, and electronic simulation targeting the processes of manufacture of wing integral panels. The modeling results can be used to calculate the die tooling, determine the panel processibility, and control panel rejection in the course of forming.« less

Development of Six Sigma methodology for CNC milling process improvements

NASA Astrophysics Data System (ADS)

Ismail, M. N.; Rose, A. N. M.; Mohammed, N. Z.; Rashid, M. F. F. Ab

2017-10-01

Quality and productivity have been identified as an important role in any organization, especially for manufacturing sectors to gain more profit that leads to success of a company. This paper reports a work improvement project in Kolej Kemahiran Tinggi MARA Kuantan. It involves problem identification in production of “Khufi” product and proposing an effective framework to improve the current situation effectively. Based on the observation and data collection on the work in progress (WIP) product, the major problem has been identified related to function of the product which is the parts can’t assemble properly due to dimension of the product is out of specification. The six sigma has been used as a methodology to study and improve of the problems identified. Six Sigma is a highly statistical and data driven approach to solving complex business problems. It uses a methodical five phase approach define, measure, analysis, improve and control (DMAIC) to help understand the process and the variables that affect it so that can be optimized the processes. Finally, the root cause and solution for the production of “Khufi” problem has been identified and implemented then the result for this product was successfully followed the specification of fitting.

Oxygen Generation System Laptop Bus Controller Flight Software

NASA Technical Reports Server (NTRS)

Rowe, Chad; Panter, Donna

2009-01-01

The Oxygen Generation System Laptop Bus Controller Flight Software was developed to allow the International Space Station (ISS) program to activate specific components of the Oxygen Generation System (OGS) to perform a checkout of key hardware operation in a microgravity environment, as well as to perform preventative maintenance operations of system valves during a long period of what would otherwise be hardware dormancy. The software provides direct connectivity to the OGS Firmware Controller with pre-programmed tasks operated by on-orbit astronauts to exercise OGS valves and motors. The software is used to manipulate the pump, separator, and valves to alleviate the concerns of hardware problems due to long-term inactivity and to allow for operational verification of microgravity-sensitive components early enough so that, if problems are found, they can be addressed before the hardware is required for operation on-orbit. The decision was made to use existing on-orbit IBM ThinkPad A31p laptops and MIL-STD-1553B interface cards as the hardware configuration. The software at the time of this reporting was developed and tested for use under the Windows 2000 Professional operating system to ensure compatibility with the existing on-orbit computer systems.

Optimized method for manufacturing large aspheric surfaces

NASA Astrophysics Data System (ADS)

Zhou, Xusheng; Li, Shengyi; Dai, Yifan; Xie, Xuhui

2007-12-01

Aspheric optics are being used more and more widely in modern optical systems, due to their ability of correcting aberrations, enhancing image quality, enlarging the field of view and extending the range of effect, while reducing the weight and volume of the system. With optical technology development, we have more pressing requirement to large-aperture and high-precision aspheric surfaces. The original computer controlled optical surfacing (CCOS) technique cannot meet the challenge of precision and machining efficiency. This problem has been thought highly of by researchers. Aiming at the problem of original polishing process, an optimized method for manufacturing large aspheric surfaces is put forward. Subsurface damage (SSD), full aperture errors and full band of frequency errors are all in control of this method. Lesser SSD depth can be gained by using little hardness tool and small abrasive grains in grinding process. For full aperture errors control, edge effects can be controlled by using smaller tools and amendment model with material removal function. For full band of frequency errors control, low frequency errors can be corrected with the optimized material removal function, while medium-high frequency errors by using uniform removing principle. With this optimized method, the accuracy of a K9 glass paraboloid mirror can reach rms 0.055 waves (where a wave is 0.6328μm) in a short time. The results show that the optimized method can guide large aspheric surface manufacturing effectively.

A comprehensive Network Security Risk Model for process control networks.

PubMed

Henry, Matthew H; Haimes, Yacov Y

2009-02-01

The risk of cyber attacks on process control networks (PCN) is receiving significant attention due to the potentially catastrophic extent to which PCN failures can damage the infrastructures and commodity flows that they support. Risk management addresses the coupled problems of (1) reducing the likelihood that cyber attacks would succeed in disrupting PCN operation and (2) reducing the severity of consequences in the event of PCN failure or manipulation. The Network Security Risk Model (NSRM) developed in this article provides a means of evaluating the efficacy of candidate risk management policies by modeling the baseline risk and assessing expectations of risk after the implementation of candidate measures. Where existing risk models fall short of providing adequate insight into the efficacy of candidate risk management policies due to shortcomings in their structure or formulation, the NSRM provides model structure and an associated modeling methodology that captures the relevant dynamics of cyber attacks on PCN for risk analysis. This article develops the NSRM in detail in the context of an illustrative example.

Optically-controlled long-term storage and release of thermal energy in phase-change materials.

PubMed

Han, Grace G D; Li, Huashan; Grossman, Jeffrey C

2017-11-13

Thermal energy storage offers enormous potential for a wide range of energy technologies. Phase-change materials offer state-of-the-art thermal storage due to high latent heat. However, spontaneous heat loss from thermally charged phase-change materials to cooler surroundings occurs due to the absence of a significant energy barrier for the liquid-solid transition. This prevents control over the thermal storage, and developing effective methods to address this problem has remained an elusive goal. Herein, we report a combination of photo-switching dopants and organic phase-change materials as a way to introduce an activation energy barrier for phase-change materials solidification and to conserve thermal energy in the materials, allowing them to be triggered optically to release their stored latent heat. This approach enables the retention of thermal energy (about 200 J g -1 ) in the materials for at least 10 h at temperatures lower than the original crystallization point, unlocking opportunities for portable thermal energy storage systems.

A Review of Recent Advances in Research on PM2.5 in China

PubMed Central

Zou, Jiale; Yang, Wei; Li, Chun-Qing

2018-01-01

PM2.5 pollution has become a severe problem in China due to rapid industrialization and high energy consumption. It can cause increases in the incidence of various respiratory diseases and resident mortality rates, as well as increase in the energy consumption in heating, ventilation, and air conditioning (HVAC) systems due to the need for air purification. This paper reviews and studies the sources of indoor and outdoor PM2.5, the impact of PM2.5 pollution on atmospheric visibility, occupational health, and occupants’ behaviors. This paper also presents current pollution status in China, the relationship between indoor and outdoor PM2.5, and control of indoor PM2.5, and finally presents analysis and suggestions for future research. PMID:29498704

Normal Untreated Jurkat Cells

NASA Technical Reports Server (NTRS)

2004-01-01

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. The objective of the research was to define a way to differentiate between effects due to microgravity and those due to possible stress from non-optimal spaceflight conditions. These Jurkat cells, a human acute T-cell leukemia was obtained to evaluate three types of potential experimental stressors: a) Temperature elevation; b) Serum starvation; and c) Centrifugal force. The data from previous spaceflight experiments showed that actin filaments and cell shape are significantly different for the control. These normal cells serve as the baseline for future spaceflight experiments.

Microgravity

NASA Image and Video Library

2004-04-15

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. The objective of the research was to define a way to differentiate between effects due to microgravity and those due to possible stress from non-optimal spaceflight conditions. These Jurkat cells, a human acute T-cell leukemia was obtained to evaluate three types of potential experimental stressors: a) Temperature elevation; b) Serum starvation; and c) Centrifugal force. The data from previous spaceflight experiments showed that actin filaments and cell shape are significantly different for the control. These normal cells serve as the baseline for future spaceflight experiments.

A Review of Recent Advances in Research on PM2.5 in China.

PubMed

Lin, Yaolin; Zou, Jiale; Yang, Wei; Li, Chun-Qing

2018-03-02

PM 2.5 pollution has become a severe problem in China due to rapid industrialization and high energy consumption. It can cause increases in the incidence of various respiratory diseases and resident mortality rates, as well as increase in the energy consumption in heating, ventilation, and air conditioning (HVAC) systems due to the need for air purification. This paper reviews and studies the sources of indoor and outdoor PM 2.5 , the impact of PM 2.5 pollution on atmospheric visibility, occupational health, and occupants' behaviors. This paper also presents current pollution status in China, the relationship between indoor and outdoor PM 2.5 , and control of indoor PM 2.5 , and finally presents analysis and suggestions for future research.

A network flow model for load balancing in circuit-switched multicomputers

NASA Technical Reports Server (NTRS)

Bokhari, Shahid H.

1990-01-01

In multicomputers that utilize circuit switching or wormhole routing, communication overhead depends largely on link contention - the variation due to distance between nodes is negligible. This has a major impact on the load balancing problem. In this case, there are some nodes with excess load (sources) and others with deficit load (sinks) and it is required to find a matching of sources to sinks that avoids contention. The problem is made complex by the hardwired routing on currently available machines: the user can control only which nodes communicate but not how the messages are routed. Network flow models of message flow in the mesh and the hypercube were developed to solve this problem. The crucial property of these models is the correspondence between minimum cost flows and correctly routed messages. To solve a given load balancing problem, a minimum cost flow algorithm is applied to the network. This permits one to determine efficiently a maximum contention free matching of sources to sinks which, in turn, tells one how much of the given imbalance can be eliminated without contention.

Auditory Deprivation Does Not Impair Executive Function, But Language Deprivation Might: Evidence From a Parent-Report Measure in Deaf Native Signing Children

PubMed Central

Hall, Matthew L.; Eigsti, Inge-Marie; Bortfeld, Heather; Lillo-Martin, Diane

2017-01-01

Deaf children are often described as having difficulty with executive function (EF), often manifesting in behavioral problems. Some researchers view these problems as a consequence of auditory deprivation; however, the behavioral problems observed in previous studies may not be due to deafness but to some other factor, such as lack of early language exposure. Here, we distinguish these accounts by using the BRIEF EF parent report questionnaire to test for behavioral problems in a group of Deaf children from Deaf families, who have a history of auditory but not language deprivation. For these children, the auditory deprivation hypothesis predicts behavioral impairments; the language deprivation hypothesis predicts no group differences in behavioral control. Results indicated that scores among the Deaf native signers (n = 42) were age-appropriate and similar to scores among the typically developing hearing sample (n = 45). These findings are most consistent with the language deprivation hypothesis, and provide a foundation for continued research on outcomes of children with early exposure to sign language. PMID:27624307

Pigeon interaction mode switch-based UAV distributed flocking control under obstacle environments.

PubMed

Qiu, Huaxin; Duan, Haibin

2017-11-01

Unmanned aerial vehicle (UAV) flocking control is a serious and challenging problem due to local interactions and changing environments. In this paper, a pigeon flocking model and a pigeon coordinated obstacle-avoiding model are proposed based on a behavior that pigeon flocks will switch between hierarchical and egalitarian interaction mode at different flight phases. Owning to the similarity between bird flocks and UAV swarms in essence, a distributed flocking control algorithm based on the proposed pigeon flocking and coordinated obstacle-avoiding models is designed to coordinate a heterogeneous UAV swarm to fly though obstacle environments with few informed individuals. The comparative simulation results are elaborated to show the feasibility, validity and superiority of our proposed algorithm. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Autocorrelated process control: Geometric Brownian Motion approach versus Box-Jenkins approach

NASA Astrophysics Data System (ADS)

Salleh, R. M.; Zawawi, N. I.; Gan, Z. F.; Nor, M. E.

2018-04-01

Existing of autocorrelation will bring a significant effect on the performance and accuracy of process control if the problem does not handle carefully. When dealing with autocorrelated process, Box-Jenkins method will be preferred because of the popularity. However, the computation of Box-Jenkins method is too complicated and challenging which cause of time-consuming. Therefore, an alternative method which known as Geometric Brownian Motion (GBM) is introduced to monitor the autocorrelated process. One real case of furnace temperature data is conducted to compare the performance of Box-Jenkins and GBM methods in monitoring autocorrelation process. Both methods give the same results in terms of model accuracy and monitoring process control. Yet, GBM is superior compared to Box-Jenkins method due to its simplicity and practically with shorter computational time.

Patients with mental problems - the most defenseless travellers.

PubMed

Felkai, Peter; Kurimay, Tamas

2017-09-01

Severe mental illness occurring abroad is a difficult situation for patients, their families, and for the local medical community. Patients with mental problem are doublely stigmatized due to their mental illness and because they are foreigners in an unfamiliar country. The appropriate treatment is often delayed, while patients are often dealt with in a manner that violates their human rights. Moreover, repatriation - which is vital in this case - is often delayed due to the lack of international protocols for the transportation and treatment of mentally ill travelers. Authors analyzed several factors related to acute mental health problems during travel: the etiology of symptoms, the appropriate treatment possibilities abroad, and medical evacuation and repatriation of the psychotic patient. The article presents a brief review of travel-related mental disorders, the epidemiology of mental health issues faced by travelers, and the significance of pre-travel advice for these patients. The first problem is to recognize (and redress) the particular challenges faced by a psychotic patient in a strange country. The second challenge is to prepare the patients, often in a poor psychiatric state, for medical evacuation by commercial aircraft. Another important question is the best way to take the patient through customs and security control. All of these, as yet unresolved, issues can make the mental patient virtually defenseless. Although timely repatriation of a mentally ill patient is vital and urgent, most travel insurance policies exclude treatment and repatriation costs incurred due to acute mental illness. The high cost of treatment and repatriation must be paid by the patient or their family, which could lead to severe financial strain or insolvency. Changing the approaches taken by the local mental health care community, police, airport security, and insurance companies remain a challenge for psychiatrists. © International Society of Travel Medicine, 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

Control problem for a system of linear loaded differential equations

NASA Astrophysics Data System (ADS)

Barseghyan, V. R.; Barseghyan, T. V.

2018-04-01

The problem of control and optimal control for a system of linear loaded differential equations is considered. Necessary and sufficient conditions for complete controllability and conditions for the existence of a program control and the corresponding motion are formulated. The explicit form of control action for the control problem is constructed and a method for solving the problem of optimal control is proposed.

Interpersonal Distress is Associated with Sleep and Arousal in Insomnia and Good Sleepers

PubMed Central

Gunn, Heather E.; Troxel, Wendy M.; Hall, Martica; Buysse, Daniel J.

2014-01-01

Objective The interpersonal environment is strongly linked to sleep. However, little is known about interpersonal distress and its association with sleep. We examined the associations among interpersonal distress, objective and subjective sleep in people with and without insomnia. Methods Participants in this cross-sectional observational study included men and women with insomnia (n = 28) and good sleeper controls (n = 38). Interpersonal distress was measured with the Inventory of Interpersonal Problems. Sleep parameters included insomnia severity, self-reported presleep arousal, and sleep quality; and polysomnographically-assessed sleep latency (SL), total sleep time (TST), wake after sleep onset (WASO), percent delta (stage 3+4 NREM), percent REM, and EEG beta power. Hierarchical Linear Regression was used to assess the relationship between distress from interpersonal problems and sleep and the extent to which relationships differed among insomnia patients and controls. Results More interpersonal distress was associated with more self-reported arousal and higher percentage of REM. More interpersonal distress was associated with greater insomnia severity and more cognitive presleep arousal for individuals with insomnia, but not for controls. Contrary to expectations, interpersonal distress was associated with shorter sleep latency in the insomnia group. Results were attenuated, but still significant, after adjusting for depression symptoms. Conclusion Distress from interpersonal problems is associated with greater self-reported arousal and higher percent REM. Individuals with insomnia who report more distress from interpersonal problems have greater insomnia severity and cognitive presleep arousal, perhaps due to rumination. These findings extend our knowledge of the association between interpersonal stressors and sleep. Assessment and consideration of interpersonal distress could provide a novel target for insomnia treatment. PMID:24529045

Interpersonal distress is associated with sleep and arousal in insomnia and good sleepers.

PubMed

Gunn, Heather E; Troxel, Wendy M; Hall, Martica H; Buysse, Daniel J

2014-03-01

The interpersonal environment is strongly linked to sleep. However, little is known about interpersonal distress and its association with sleep. We examined the associations among interpersonal distress, objective and subjective sleep in people with and without insomnia. Participants in this cross-sectional observational study included men and women with insomnia (n = 28) and good sleeper controls (n = 38). Interpersonal distress was measured with the Inventory of Interpersonal Problems. Sleep parameters included insomnia severity, self-reported presleep arousal, and sleep quality; and polysomnographically-assessed sleep latency (SL), total sleep time (TST), wake after sleep onset (WASO), percent delta (stage 3 + 4 NREM), percent REM, and EEG beta power. Hierarchical linear regression was used to assess the relationship between distress from interpersonal problems and sleep and the extent to which relationships differed among insomnia patients and controls. More interpersonal distress was associated with more self-reported arousal and higher percentage of REM. More interpersonal distress was associated with greater insomnia severity and more cognitive presleep arousal for individuals with insomnia, but not for controls. Contrary to expectations, interpersonal distress was associated with shorter sleep latency in the insomnia group. Results were attenuated, but still significant, after adjusting for depression symptoms. Distress from interpersonal problems is associated with greater self-reported arousal and higher percent REM. Individuals with insomnia who report more distress from interpersonal problems have greater insomnia severity and cognitive presleep arousal, perhaps due to rumination. These findings extend our knowledge of the association between interpersonal stressors and sleep. Assessment and consideration of interpersonal distress could provide a novel target for insomnia treatment. Copyright © 2013 Elsevier Inc. All rights reserved.

Discrete Time McKean–Vlasov Control Problem: A Dynamic Programming Approach

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

Pham, Huyên, E-mail: pham@math.univ-paris-diderot.fr; Wei, Xiaoli, E-mail: tyswxl@gmail.com

We consider the stochastic optimal control problem of nonlinear mean-field systems in discrete time. We reformulate the problem into a deterministic control problem with marginal distribution as controlled state variable, and prove that dynamic programming principle holds in its general form. We apply our method for solving explicitly the mean-variance portfolio selection and the multivariate linear-quadratic McKean–Vlasov control problem.

Quadrat Data for Fermilab Prairie Plant Survey

Science.gov Websites

Quadrat Data 2012 Quadrat Data 2013 Quadrat Data None taken by volunteers in 2014 due to weather problems . 2015 Quadrat Data 2016 Quadrat Data None taken by volunteers in 2017 due to weather and other problems

Two Decades of Negative Thermal Expansion Research: Where Do We Stand?

PubMed Central

Lind, Cora

2012-01-01

Negative thermal expansion (NTE) materials have become a rapidly growing area of research over the past two decades. The initial discovery of materials displaying NTE over a large temperature range, combined with elucidation of the mechanism behind this unusual property, was followed by predictions that these materials will find use in various applications through controlled thermal expansion composites. While some patents have been filed and devices built, a number of obstacles have prevented the widespread implementation of NTE materials to date. This paper reviews NTE materials that contract due to transverse atomic vibrations, their potential for use in controlled thermal expansion composites, and known problems that could interfere with such applications. PMID:28817027

A Novel Numerical Method for Fuzzy Boundary Value Problems

NASA Astrophysics Data System (ADS)

Can, E.; Bayrak, M. A.; Hicdurmaz

2016-05-01

In the present paper, a new numerical method is proposed for solving fuzzy differential equations which are utilized for the modeling problems in science and engineering. Fuzzy approach is selected due to its important applications on processing uncertainty or subjective information for mathematical models of physical problems. A second-order fuzzy linear boundary value problem is considered in particular due to its important applications in physics. Moreover, numerical experiments are presented to show the effectiveness of the proposed numerical method on specific physical problems such as heat conduction in an infinite plate and a fin.

Heuristic methods for the single machine scheduling problem with different ready times and a common due date

NASA Astrophysics Data System (ADS)

Birgin, Ernesto G.; Ronconi, Débora P.

2012-10-01

The single machine scheduling problem with a common due date and non-identical ready times for the jobs is examined in this work. Performance is measured by the minimization of the weighted sum of earliness and tardiness penalties of the jobs. Since this problem is NP-hard, the application of constructive heuristics that exploit specific characteristics of the problem to improve their performance is investigated. The proposed approaches are examined through a computational comparative study on a set of 280 benchmark test problems with up to 1000 jobs.

Effects of high-fidelity patient simulation led clinical reasoning course: Focused on nursing core competencies, problem solving, and academic self-efficacy.

PubMed

Lee, JuHee; Lee, Yoonju; Lee, Senah; Bae, Juyeon

2016-01-01

To examine the effects of high-fidelity patient simulation (HFPS) led clinical reasoning course among undergraduate nursing students. A quasi-experimental study of non-equivalent control group pretest-post test design was applied. A total of 49 senior nursing students participated in this study. The experimental group consisted of the students who took the "clinical reasoning" course (n = 23) while the control group consisted of students who did not (n = 26). Self-administered scales including the nursing core competencies, problem solving, academic self-efficacy, and Kolb learning style inventory were analyzed quantitatively using SPSS version 20.0. Data analysis was conducted using one-way ancova due to a significant difference in nursing core competencies between the experimental group and control group. There was a significant improvement in nursing core competencies in the experimental group (F = 7.747, P = 0.008). The scores of problem solving and academic self-efficacy were higher in the experimental group after the HFPS led clinical reasoning course without statistical difference. There is a need for the development of effective instructional methods to improve learning outcomes in nursing education. Future research is needed related to simulation education as well as management strategies so that learning outcomes can be achieved within different students' learning style. © 2015 The Authors. Japan Journal of Nursing Science © 2015 Japan Academy of Nursing Science.

Bladder Control Problems: Medications for Treating Urinary Incontinence

MedlinePlus

Bladder control: Medications for urinary problems Learn about medications used to treat bladder control problems, including how they work to treat urinary ... your doctor's suggestions for bladder retraining. But bladder control remains a problem. What else can you do? ...

How are things adding up? Neural differences between arithmetic operations are due to general problem solving strategies.

PubMed

Tschentscher, Nadja; Hauk, Olaf

2014-05-15

A number of previous studies have interpreted differences in brain activation between arithmetic operation types (e.g. addition and multiplication) as evidence in favor of distinct cortical representations, processes or neural systems. It is still not clear how differences in general task complexity contribute to these neural differences. Here, we used a mental arithmetic paradigm to disentangle brain areas related to general problem solving from those involved in operation type specific processes (addition versus multiplication). We orthogonally varied operation type and complexity. Importantly, complexity was defined not only based on surface criteria (for example number size), but also on the basis of individual participants' strategy ratings, which were validated in a detailed behavioral analysis. We replicated previously reported operation type effects in our analyses based on surface criteria. However, these effects vanished when controlling for individual strategies. Instead, procedural strategies contrasted with memory retrieval reliably activated fronto-parietal and motor regions, while retrieval strategies activated parietal cortices. This challenges views that operation types rely on partially different neural systems, and suggests that previously reported differences between operation types may have emerged due to invalid measures of complexity. We conclude that mental arithmetic is a powerful paradigm to study brain networks of abstract problem solving, as long as individual participants' strategies are taken into account. Copyright © 2014 Elsevier Inc. All rights reserved.

Feedback attitude sliding mode regulation control of spacecraft using arm motion

NASA Astrophysics Data System (ADS)

Shi, Ye; Liang, Bin; Xu, Dong; Wang, Xueqian; Xu, Wenfu

2013-09-01

The problem of spacecraft attitude regulation based on the reaction of arm motion has attracted extensive attentions from both engineering and academic fields. Most of the solutions of the manipulator’s motion tracking problem just achieve asymptotical stabilization performance, so that these controllers cannot realize precise attitude regulation because of the existence of non-holonomic constraints. Thus, sliding mode control algorithms are adopted to stabilize the tracking error with zero transient process. Due to the switching effects of the variable structure controller, once the tracking error reaches the designed hyper-plane, it will be restricted to this plane permanently even with the existence of external disturbances. Thus, precise attitude regulation can be achieved. Furthermore, taking the non-zero initial tracking errors and chattering phenomenon into consideration, saturation functions are used to replace sign functions to smooth the control torques. The relations between the upper bounds of tracking errors and the controller parameters are derived to reveal physical characteristic of the controller. Mathematical models of free-floating space manipulator are established and simulations are conducted in the end. The results show that the spacecraft’s attitude can be regulated to the position as desired by using the proposed algorithm, the steady state error is 0.000 2 rad. In addition, the joint tracking trajectory is smooth, the joint tracking errors converges to zero quickly with a satisfactory continuous joint control input. The proposed research provides a feasible solution for spacecraft attitude regulation by using arm motion, and improves the precision of the spacecraft attitude regulation.

Multi-criteria analysis for PM10 planning

NASA Astrophysics Data System (ADS)

Pisoni, Enrico; Carnevale, Claudio; Volta, Marialuisa

To implement sound air quality policies, Regulatory Agencies require tools to evaluate outcomes and costs associated to different emission reduction strategies. These tools are even more useful when considering atmospheric PM10 concentrations due to the complex nonlinear processes that affect production and accumulation of the secondary fraction of this pollutant. The approaches presented in the literature (Integrated Assessment Modeling) are mainly cost-benefit and cost-effective analysis. In this work, the formulation of a multi-objective problem to control particulate matter is proposed. The methodology defines: (a) the control objectives (the air quality indicator and the emission reduction cost functions); (b) the decision variables (precursor emission reductions); (c) the problem constraints (maximum feasible technology reductions). The cause-effect relations between air quality indicators and decision variables are identified tuning nonlinear source-receptor models. The multi-objective problem solution provides to the decision maker a set of not-dominated scenarios representing the efficient trade-off between the air quality benefit and the internal costs (emission reduction technology costs). The methodology has been implemented for Northern Italy, often affected by high long-term exposure to PM10. The source-receptor models used in the multi-objective analysis are identified processing long-term simulations of GAMES multiphase modeling system, performed in the framework of CAFE-Citydelta project.

Park system concept for environmental sustainabilityin urban spatial development

NASA Astrophysics Data System (ADS)

Uniaty, Q.

2018-01-01

Urban Park System is an integrated concept between nature system and urban life. The problems caused by urban population activity resulted in the need to increase the balance between two systems. Establishment of urban park system is a response to the need for resilience of urban space structures. As an ideal requirement it needs to be built integration between the ecological, social, economic, aesthetic aspects of urban landscape architecture. The methodology was developed based on an approach to issues affecting the conditions due to urban issues and its relation to the development efforts of urban park system; Observation of Jakarta problem was obtained based on published studies and data, literature, characteristic and potential analyzes, local physical, from limited field observations. Both are simple methods aimed to describe the nature of a condition as well as form characteristics of problems in controlling the development of region, to examine the causes and symptoms. This method try to assess an object study compared between the conditions before and after. The benefits of urban park system development will not only improve the urban environment, but the value of urban pride, identity and control urban growth in line with efforts to improve the balance between conservation and development. Integrated urban park system will enhance the multifunctional role, connectivity, habitability, durability, identity and investment.

Issues in prevention of iron deficiency anemia in India.

PubMed

Anand, Tanu; Rahi, Manju; Sharma, Pragya; Ingle, Gopal K

2014-01-01

Iron deficiency anemia (IDA) continues to be major public health problem in India. It is estimated that about 20% of maternal deaths are directly related to anemia and another 50% of maternal deaths are associated with it. The question, therefore, is why, despite being the first country to launch the National Nutritional Anemia Prophylaxis Programme in 1970, the problem of IDA remains so widespread. As is to be expected, the economic implications of IDA are also massive. The issues of control of IDA in India are multiple. Inadequate dietary intake of iron, defective iron absorption, increased iron requirements due to repeated pregnancies and lactation, poor iron reserves at birth, timing of umbilical cord clamping, timing and type of complementary food introduction, frequency of infections in children, and excessive physiological blood loss during adolescence and pregnancy are some of the causes responsible for the high prevalence of anemia in India. In addition, there are other multiple programmatic and organizational issues. This review, therefore, is an attempt to examine the current burden of anemia in India, its epidemiology, and the various issues regarding its prevention and control, as well as to offer some innovative approaches to deal with this major health problem. Copyright © 2014 Elsevier Inc. All rights reserved.

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.

Numerical Study of Groundwater Flow and Salinity Distribution Cycling Controlled by Seawater/Freshwater Interaction in Karst Aquifer Using SEAWAT

NASA Astrophysics Data System (ADS)

Xu, Z.; Hu, B.

2017-12-01

The interest to predict seawater intrusion and salinity distribution in Woodville Karst Plain (WKP) has increased due to the huge challenge on quality of drinkable water and serious environmental problems. Seawater intrudes into the conduit system from submarine karst caves at Spring Creek Spring due to density difference and sea level rising, nowadays the low salinity has been detected at Wakulla Spring which is 18 km from coastal line. The groundwater discharge at two major springs and salinity distribution in this area is controlled by the seawater/freshwater interaction under different rainfall conditions: during low rainfall periods, seawater flow into the submarine spring through karst windows, then the salinity rising at the submarine spring leads to seawater further intrudes into conduit system; during high rainfall periods, seawater is pushed out by fresh water discharge at submarine spring. The previous numerical studies of WKP mainly focused on the density independent transport modeling and seawater/freshwater discharge at major karst springs, in this study, a SEAWAT model has been developed to fully investigate the salinity distribution in the WKP under repeating phases of low rainfall and high rainfall periods, the conduit system was simulated as porous media with high conductivity and porosity. The precipitation, salinity and discharge at springs were used to calibrate the model. The results showed that the salinity distribution in porous media and conduit system is controlled by the rainfall change, in general, the salinity distribution inland under low rainfall conditions is much higher and wider than the high rainfall conditions. The results propose a prediction on the environmental problem caused by seawater intrusion in karst coastal aquifer, in addition, provide a visual and scientific basis for future groundwater remediation.

Changes in melatonin secretion in tourists after rapid movement to another lighting zone without transition of time zone.

PubMed

Wieczorek, Joanna; Blazejczyk, Krzysztof; Morita, Takeshi

2016-01-01

Most of the research in the field of Chronobiology is focused on the problem of the circadian rhythms (CR) desynchronization. In travelers, it results mostly from the changes of surrounding: photoperiod, local climate conditions (radiation and thermal load) and behavior (e.g. type and place of tourism and activity level). Until now, it was not documented whether the changes in melatonin (MLT) secretion occur in effect of mid-distance transparallel travels (TpT), without complications arising due to time-zone transitions (e.g. jet-lag syndrome). To cope with this problem, a special field experiment was carried out. In the experiment, MLT characteristics were examined twice a year in real conditions through a group of young tourists (23-26 years old) at their place of habitual residence (Warsaw, Poland), and at their tourist destination (Tromso, Norway). Transition to circumpolar zone in summer has resulted in insignificant reduction in melatonin peak value (MPV) compared to preflight control (2 days before travel) and the melatonin peak time (MPT) was delayed. However, after traveling southward on the returning flight, MPV was lower compared to control and MPT was advanced. In winter, MPV was insignificantly higher in comparison to preflight control and MPT was almost unchanged. While changes in MPV do not depend on season, flight direction and day of stay after flight than MPT was differentiated seasonally and due to direction of flight. MPV and MPT were significantly modified by characteristics of individual light exposure during daytime and evening. The experiment showed also that in real conditions activity level is an important factor affected melatonin peak in tourists. In winter, greater daytime activity significantly influenced earlier MPT occurrence, both after northward and southward flights.

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

Gaitsgory, Vladimir, E-mail: vladimir.gaitsgory@mq.edu.au; Rossomakhine, Sergey, E-mail: serguei.rossomakhine@flinders.edu.au

The paper aims at the development of an apparatus for analysis and construction of near optimal solutions of singularly perturbed (SP) optimal controls problems (that is, problems of optimal control of SP systems) considered on the infinite time horizon. We mostly focus on problems with time discounting criteria but a possibility of the extension of results to periodic optimization problems is discussed as well. Our consideration is based on earlier results on averaging of SP control systems and on linear programming formulations of optimal control problems. The idea that we exploit is to first asymptotically approximate a given problem ofmore » optimal control of the SP system by a certain averaged optimal control problem, then reformulate this averaged problem as an infinite-dimensional linear programming (LP) problem, and then approximate the latter by semi-infinite LP problems. We show that the optimal solution of these semi-infinite LP problems and their duals (that can be found with the help of a modification of an available LP software) allow one to construct near optimal controls of the SP system. We demonstrate the construction with two numerical examples.« less

Interference and problem size effect in multiplication fact solving: Individual differences in brain activations and arithmetic performance.

PubMed

De Visscher, Alice; Vogel, Stephan E; Reishofer, Gernot; Hassler, Eva; Koschutnig, Karl; De Smedt, Bert; Grabner, Roland H

2018-05-15

In the development of math ability, a large variability of performance in solving simple arithmetic problems is observed and has not found a compelling explanation yet. One robust effect in simple multiplication facts is the problem size effect, indicating better performance for small problems compared to large ones. Recently, behavioral studies brought to light another effect in multiplication facts, the interference effect. That is, high interfering problems (receiving more proactive interference from previously learned problems) are more difficult to retrieve than low interfering problems (in terms of physical feature overlap, namely the digits, De Visscher and Noël, 2014). At the behavioral level, the sensitivity to the interference effect is shown to explain individual differences in the performance of solving multiplications in children as well as in adults. The aim of the present study was to investigate the individual differences in multiplication ability in relation to the neural interference effect and the neural problem size effect. To that end, we used a paradigm developed by De Visscher, Berens, et al. (2015) that contrasts the interference effect and the problem size effect in a multiplication verification task, during functional magnetic resonance imaging (fMRI) acquisition. Forty-two healthy adults, who showed high variability in an arithmetic fluency test, participated in our fMRI study. In order to control for the general reasoning level, the IQ was taken into account in the individual differences analyses. Our findings revealed a neural interference effect linked to individual differences in multiplication in the left inferior frontal gyrus, while controlling for the IQ. This interference effect in the left inferior frontal gyrus showed a negative relation with individual differences in arithmetic fluency, indicating a higher interference effect for low performers compared to high performers. This region is suggested in the literature to be involved in resolution of proactive interference. Besides, no correlation between the neural problem size effect and multiplication performance was found. This study supports the idea that the interference due to similarities/overlap of physical traits (the digits) is crucial in memorizing arithmetic facts and in determining individual differences in arithmetic. Copyright © 2018 Elsevier Inc. All rights reserved.

Occupation-specific screening for future sickness absence: criterion validity of the trucker strain monitor (TSM).

PubMed

De Croon, Einar M; Blonk, Roland W B; Sluiter, Judith K; Frings-Dresen, Monique H W

2005-02-01

Monitoring psychological job strain may help occupational physicians to take preventive action at the appropriate time. For this purpose, the 10-item trucker strain monitor (TSM) assessing work-related fatigue and sleeping problems in truck drivers was developed. This study examined (1) test-retest reliability, (2) criterion validity of the TSM with respect to future sickness absence due to psychological health complaints and (3) usefulness of the TSM two-scales structure. The TSM and self-administered questionnaires, providing information about stressful working conditions (job control and job demands) and sickness absence, were sent to a random sample of 2000 drivers in 1998. Of the 1123 responders, 820 returned a completed questionnaire 2 years later (response: 72%). The TSM work-related fatigue scale, the TSM sleeping problems scale and the TSM composite scale showed satisfactory 2-year test-retest reliability (coefficient r=0.62, 0.66 and 0.67, respectively). The work-related fatigue, sleeping problems scale and composite scale had sensitivities of 61, 65 and 61%, respectively in identifying drivers with future sickness absence due to psychological health complaints. The specificity and positive predictive value of the TSM composite scale were 77 and 11%, respectively. The work-related fatigue scale and the sleeping problems scale were moderately strong correlated (r=0.62). However, stressful working conditions were differentially associated with the two scales. The results support the test-retest reliability, criterion validity and two-factor structure of the TSM. In general, the results suggest that the use of occupation-specific psychological job strain questionnaires is fruitful.

[Witch hunt and hypotheses loss].

PubMed

Köhler, Dieter

2015-12-01

At this time randomized controlled studies (RCT) in clinical trials usually have high quality. But this quality is only true for the included patients (intrinsic validity). It is common to generalize the results to more or less similar patients. This inductive method is prohibited in epistemology what is known for 250 years (D Hume, K R Popper). Therefore the external validity for the data of RCT is low. To solve this problem additional clinical and pathophysiological based data are necessary to generalize the results. Unfortunately RCT show less quality in their premises. This is partly due to the influence of the pharmaceutical industry. A loss of universality of the hypothesis for RCT decreases basically the extrinsic validity. The articles describe this problem with examples. © Georg Thieme Verlag KG Stuttgart · New York.

Electrostatic antenna space environment interaction study

NASA Technical Reports Server (NTRS)

Katz, I.

1981-01-01

The interactions of the electrostatic antenna with the space environment in both low Earth orbit and geosynchronous orbit are investigated. It is concluded that the electrostatically controlled membrane mirror is a viable concept for space applications. However, great care must be taken to enclose the high voltage electrodes in a Faraday cage structure to separate the high voltage region from the ambient plasma. For this reason, metallized cloth is not acceptable as a membrane material. Conventional spacecraft charging at geosynchronous orbit should not be a problem provided ancillary structures (such as booms) are given nonnegligible conductivity and adequate grounding. Power loss due to plasma electrons entering the high field region is a potentially serious problem. In low earth orbit any opening whatever in the Faraday cage is likely to produce an unacceptable power drain.

Verification testing of the PKI collector at Sandia National Laboratories, Albuquerque, New Mexico

NASA Technical Reports Server (NTRS)

Hauger, J. S.; Pond, S. L.

1982-01-01

Verification testing of a solar collector was undertaken prior to its operation as part of an industrial process heat plant at Capitol Concrete Products in Topeka, Kansas. Testing was performed at a control plant installed at Sandia National Laboratory, Albuquerque, New Mexico (SNLA). Early results show that plant performance is even better than anticipated and far in excess of test criteria. Overall plant efficiencies of 65 to 80 percent were typical during hours of good insolation. A number of flaws and imperfections were detected during operability testing, the most important being a problem in elevation drive alignment due to a manufacturing error. All problems were corrected as they occurred and the plant, with over 40 hours of operation, is currently continuing operability testing in a wholly-automatic mode.

Verification testing of the PKI collector at Sandia National Laboratories, Albuquerque, New Mexico

NASA Astrophysics Data System (ADS)

Hauger, J. S.; Pond, S. L.

1982-07-01

Verification testing of a solar collector was undertaken prior to its operation as part of an industrial process heat plant at Capitol Concrete Products in Topeka, Kansas. Testing was performed at a control plant installed at Sandia National Laboratory, Albuquerque, New Mexico (SNLA). Early results show that plant performance is even better than anticipated and far in excess of test criteria. Overall plant efficiencies of 65 to 80 percent were typical during hours of good insolation. A number of flaws and imperfections were detected during operability testing, the most important being a problem in elevation drive alignment due to a manufacturing error. All problems were corrected as they occurred and the plant, with over 40 hours of operation, is currently continuing operability testing in a wholly-automatic mode.

Health-related effects of early part-time sick leave due to musculoskeletal disorders: a randomized controlled trial.

PubMed

Shiri, Rahman; Kausto, Johanna; Martimo, Kari-Pekka; Kaila-Kangas, Leena; Takala, Esa-Pekka; Viikari-Juntura, Eira

2013-01-01

Previously we reported that early part-time sick leave enhances return to work (RTW) among employees with musculoskeletal disorders (MSD). This paper assesses the health-related effects of this intervention. Patients aged 18-60 years who were unable to perform their regular work due to MSD were randomized to part- or full-time sick leave groups. In the former, workload was reduced by halving working time. Using validated questionnaires, we assessed pain intensity and interference with work and sleep, region-specific disability due to MSD, self-rated general health, health-related quality of life (measured via EuroQol), productivity loss, depression, and sleep disturbance at baseline, 1, 3, 8, 12, and 52 weeks. We analyzed the repeated measures data (171-356 observations) with the generalized estimating equation approach. The intervention (part-time sick leave) and control (full-time sick leave) groups did not differ with regard to pain intensity, pain interference with work and sleep, region-specific disability, productivity loss, depression, or sleep disturbance. The intervention group reported better self-rated general health (adjusted P=0.07) and health-related quality of life (adjusted P=0.02) than the control group. In subgroup analyses, the intervention was more effective among the patients whose current problem began occurring <6 weeks before baseline and those with ≤30% productivity loss at baseline. Our findings showed that part-time sick leave did not exacerbate pain-related symptoms and functional disability, but improved self-rated general health and health-related quality of life in the early stage of work disability due to MSD.

Pregnancy-associated transient osteoporosis of the hip: results of a case-control study.

PubMed

Hadji, Peyman; Boekhoff, Jelena; Hahn, Melitta; Hellmeyer, Lars; Hars, Olaf; Kyvernitakis, Ioannis

2017-12-01

The etiology and underlying mechanisms of transient of osteoporosis of the hip (TOH) during pregnancy are still unclear, since no systematic analyses exist. Our results support the hypothesis that TOH is a multifactorial disease, which is associated with immobility, dental problems, and lack of exercise in childhood. Pregnancy-associated transient osteoporosis of the hip (TOH) is a rare but severe form of osteoporosis, which may affect a subgroup of women in the last trimester of pregnancy or immediately postpartum. Common symptoms include acute pain of the hip(s) due to bone marrow edema or even hip fractures. The exact underlining mechanisms of this disorder are still unknown since no published systematic analyses exist. Out of a total of 52 TOH patients, 33 TOH patients could be matched with 33 healthy controls according to age, region, and gravity. The aim of this retrospective case-control study was to evaluate the risk factors for TOH in a homogenous population of women. The baseline characteristics of the two study groups were similar. Overall, 12.1% of the TOH patients sustained a hip fracture. Expectedly, 90.9% of the TOH patients complained about pain of the hip (p ≤ 0.001). TOH patients suffered more frequently from severe dental problems during childhood (p = 0.023) and performed less often sports before and after puberty (p ≤ 0.001), whereas the frequency of immobilization during pregnancy was threefold higher compared to the control group (p = 0.007). We found a significant increase of the TOH risk in patients with dental problems in childhood (OR 3.7; CI 1.3-10.7) as well as in patients with lack of exercise during childhood (OR 4.2; CI 1.3-12.9). Our results support the hypothesis that pregnancy-associated TOH is a multifactorial disease, to which several individual factors may contribute. Hereby, we found significant associations with immobility, dental problems, and lack of exercise in childhood.

New techniques to control salinity-wastewater reuse interactions in golf courses of the Mediterranean regions

NASA Astrophysics Data System (ADS)

Beltrao, J.; Costa, M.; Rosado, V.; Gamito, P.; Santos, R.; Khaydarova, V.

2003-04-01

Due to the lack water around the Mediterranean regions, potable water luxurious uses - as in golf courses - are increasingly contested. In order to solve this problem, non conventional water resources (effluent, gray, recycled, reclaimed, brackish), like treated wastewater, for irrigation gained increasing role in the planning and development of additional water supplies in golf courses. In most cases, the intense use of effluent for irrigation attracted public awareness in respect of contaminating pathogens and heavy metals. The contaminating effect of salinity in soil and underground water is very often neglected. The objective of this work is to present the conventional techniques to control salinity of treated wastewater and to present some results on new clean techniques to solve this problem, in the framework of the INCO-COPERNICUS project (no. IC-15CT98-0105) "Adaptation of Efficient Water Use Criteria in Marginal Regions of Europe and Middle Asia with Scarce Sources Subject to Environmental Control, Climate Change and Socio-Economic Development" and of the INCO-DC project (no. IC18-CT98-0266) "Control of Salination and Combating Desertification Effects in the Mediterranean Region. Phase II". Saline water is the most common irrigation water in arid climates. Moreover, for each region treated wastewater is always more saline than tap water, and therefore, when treated wastewater is reused in golf courses, more salinity problems occur. Conventional techniques to combat the salination process in golf courses can be characterized by four generations: 1) Problem of root zone salination by soil leaching - two options can occur - when there is an impermeable layer, salts will be concentrated above this layer; on the other hand, when there is no impermeable layer, aquifers contamination can be observed; 2) Use of subsurface trickle irrigation - economy of water, and therefore less additional salts; however the problem of groundwater contamination due to natural rain or artificial leaching remained; 3) Enhanced fertilization increases turfgrass tolerance to salinity, but the contamination will be increased by other hazardous chemicals such as nitrate; 4) Use of salt tolerant turfgrass species this technique will be very useful to the plants, but does not solve the problem os soil or groundwater contamination. When reusing treated wastewater in the Mediterranean areas, the only way to control the salination process and to maintain the sustainability of golf courses is to combat the salination problems by environmentally safe and clean techniques. These new clean techniques include: 1) Use of salt removing turfgrass species; 2) Use of drought tolerant turfgrass species - reduction of salt application by deficit irrigation; 3) Reuse of minimal levels of wastewater enough to obtain a good visual appearance GVA of the turfgrass. Regarding these new clean techniques, experiments were carried out in golf courses of Algarve, Portugal, the most southwest part of Europe. It was shown: 1) Use of salt removing turfgrass species - 3 sprinkle irrigated cultivars were studied (Agrostis solonífera L.; Cynodon dactylon, L. and Penninsetum clandestinum Hochst ex Chiov). 2) Use of drought tolerant turfgrass species -responses to several levels of sprinkle irrigation wastewater and potable water (with and without fertilization). An experimental design, known as sprinkle point source was specially used to simulate the several levels of water application, expressed by the crop coefficient kc and by the crop evapotranspiration rate ETc. Turfgrass yield was enhanced linearly with the increased application of treated wastewater. 3) Reuse of minimal levels of wastewater enough to obtain a good visual appearance GVA of the turfgrass - The minimal crop coefficient kc for a good visual appearance GVA of the turfgrass was around 1.0 to potable water irrigated mixed cultivars (with 30 kg nitrogen ha-1 month-1) and 1.2 to wastewater irrigated Bermuda grass (without any mineral fertilization). As concluding remarks, our results show that these new clean techniques are a strong and powerful tool to control salinity and to avoid soil salination and to maintain sustainability of golf courses.

Data based identification and prediction of nonlinear and complex dynamical systems

NASA Astrophysics Data System (ADS)

Wang, Wen-Xu; Lai, Ying-Cheng; Grebogi, Celso

2016-07-01

The problem of reconstructing nonlinear and complex dynamical systems from measured data or time series is central to many scientific disciplines including physical, biological, computer, and social sciences, as well as engineering and economics. The classic approach to phase-space reconstruction through the methodology of delay-coordinate embedding has been practiced for more than three decades, but the paradigm is effective mostly for low-dimensional dynamical systems. Often, the methodology yields only a topological correspondence of the original system. There are situations in various fields of science and engineering where the systems of interest are complex and high dimensional with many interacting components. A complex system typically exhibits a rich variety of collective dynamics, and it is of great interest to be able to detect, classify, understand, predict, and control the dynamics using data that are becoming increasingly accessible due to the advances of modern information technology. To accomplish these goals, especially prediction and control, an accurate reconstruction of the original system is required. Nonlinear and complex systems identification aims at inferring, from data, the mathematical equations that govern the dynamical evolution and the complex interaction patterns, or topology, among the various components of the system. With successful reconstruction of the system equations and the connecting topology, it may be possible to address challenging and significant problems such as identification of causal relations among the interacting components and detection of hidden nodes. The "inverse" problem thus presents a grand challenge, requiring new paradigms beyond the traditional delay-coordinate embedding methodology. The past fifteen years have witnessed rapid development of contemporary complex graph theory with broad applications in interdisciplinary science and engineering. The combination of graph, information, and nonlinear dynamical systems theories with tools from statistical physics, optimization, engineering control, applied mathematics, and scientific computing enables the development of a number of paradigms to address the problem of nonlinear and complex systems reconstruction. In this Review, we describe the recent advances in this forefront and rapidly evolving field, with a focus on compressive sensing based methods. In particular, compressive sensing is a paradigm developed in recent years in applied mathematics, electrical engineering, and nonlinear physics to reconstruct sparse signals using only limited data. It has broad applications ranging from image compression/reconstruction to the analysis of large-scale sensor networks, and it has become a powerful technique to obtain high-fidelity signals for applications where sufficient observations are not available. We will describe in detail how compressive sensing can be exploited to address a diverse array of problems in data based reconstruction of nonlinear and complex networked systems. The problems include identification of chaotic systems and prediction of catastrophic bifurcations, forecasting future attractors of time-varying nonlinear systems, reconstruction of complex networks with oscillatory and evolutionary game dynamics, detection of hidden nodes, identification of chaotic elements in neuronal networks, reconstruction of complex geospatial networks and nodal positioning, and reconstruction of complex spreading networks with binary data.. A number of alternative methods, such as those based on system response to external driving, synchronization, and noise-induced dynamical correlation, will also be discussed. Due to the high relevance of network reconstruction to biological sciences, a special section is devoted to a brief survey of the current methods to infer biological networks. Finally, a number of open problems including control and controllability of complex nonlinear dynamical networks are discussed. The methods outlined in this Review are principled on various concepts in complexity science and engineering such as phase transitions, bifurcations, stabilities, and robustness. The methodologies have the potential to significantly improve our ability to understand a variety of complex dynamical systems ranging from gene regulatory systems to social networks toward the ultimate goal of controlling such systems.

Associations of parenting dimensions and styles with externalizing problems of children and adolescents: An updated meta-analysis.

PubMed

Pinquart, Martin

2017-05-01

The present meta-analysis integrates research from 1,435 studies on associations of parenting dimensions and styles with externalizing symptoms in children and adolescents. Parental warmth, behavioral control, autonomy granting, and an authoritative parenting style showed very small to small negative concurrent and longitudinal associations with externalizing problems. In contrast, harsh control, psychological control, authoritarian, permissive, and neglectful parenting were associated with higher levels of externalizing problems. The strongest associations were observed for harsh control and psychological control. Parental warmth, behavioral control, harsh control, psychological control, autonomy granting, authoritative, and permissive parenting predicted change in externalizing problems over time, with associations of externalizing problems with warmth, behavioral control, harsh control, psychological control, and authoritative parenting being bidirectional. Moderating effects of sampling, child's age, form of externalizing problems, rater of parenting and externalizing problems, quality of measures, and publication status were identified. Implications for future research and practice are discussed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Control of Finite-State, Finite Memory Stochastic Systems

NASA Technical Reports Server (NTRS)

Sandell, Nils R.

1974-01-01

A generalized problem of stochastic control is discussed in which multiple controllers with different data bases are present. The vehicle for the investigation is the finite state, finite memory (FSFM) stochastic control problem. Optimality conditions are obtained by deriving an equivalent deterministic optimal control problem. A FSFM minimum principle is obtained via the equivalent deterministic problem. The minimum principle suggests the development of a numerical optimization algorithm, the min-H algorithm. The relationship between the sufficiency of the minimum principle and the informational properties of the problem are investigated. A problem of hypothesis testing with 1-bit memory is investigated to illustrate the application of control theoretic techniques to information processing problems.

Analysis of PV Advanced Inverter Functions and Setpoints under Time Series Simulation.

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

Seuss, John; Reno, Matthew J.; Broderick, Robert Joseph

Utilities are increasingly concerned about the potential negative impacts distributed PV may have on the operational integrity of their distribution feeders. Some have proposed novel methods for controlling a PV system's grid - tie inverter to mitigate poten tial PV - induced problems. This report investigates the effectiveness of several of these PV advanced inverter controls on improving distribution feeder operational metrics. The controls are simulated on a large PV system interconnected at several locations within two realistic distribution feeder models. Due to the time - domain nature of the advanced inverter controls, quasi - static time series simulations aremore » performed under one week of representative variable irradiance and load data for each feeder. A para metric study is performed on each control type to determine how well certain measurable network metrics improve as a function of the control parameters. This methodology is used to determine appropriate advanced inverter settings for each location on the f eeder and overall for any interconnection location on the feeder.« less

Reducing model uncertainty effects in flexible manipulators through the addition of passive damping

NASA Technical Reports Server (NTRS)

Alberts, T. E.

1987-01-01

An important issue in the control of practical systems is the effect of model uncertainty on closed loop performance. This is of particular concern when flexible structures are to be controlled, due to the fact that states associated with higher frequency vibration modes are truncated in order to make the control problem tractable. Digital simulations of a single-link manipulator system are employed to demonstrate that passive damping added to the flexible member reduces adverse effects associated with model uncertainty. A controller was designed based on a model including only one flexible mode. This controller was applied to larger order systems to evaluate the effects of modal truncation. Simulations using a Linear Quadratic Regulator (LQR) design assuming full state feedback illustrate the effect of control spillover. Simulations of a system using output feedback illustrate the destabilizing effect of observation spillover. The simulations reveal that the system with passive damping is less susceptible to these effects than the untreated case.

Mapping Gnss Restricted Environments with a Drone Tandem and Indirect Position Control

NASA Astrophysics Data System (ADS)

Cledat, E.; Cucci, D. A.

2017-08-01

The problem of autonomously mapping highly cluttered environments, such as urban and natural canyons, is intractable with the current UAV technology. The reason lies in the absence or unreliability of GNSS signals due to partial sky occlusion or multi-path effects. High quality carrier-phase observations are also required in efficient mapping paradigms, such as Assisted Aerial Triangulation, to achieve high ground accuracy without the need of dense networks of ground control points. In this work we consider a drone tandem in which the first drone flies outside the canyon, where GNSS constellation is ideal, visually tracks the second drone and provides an indirect position control for it. This enables both autonomous guidance and accurate mapping of GNSS restricted environments without the need of ground control points. We address the technical feasibility of this concept considering preliminary real-world experiments in comparable conditions and we perform a mapping accuracy prediction based on a simulation scenario.

Pulpwood, pesticides, and people. Controlling spruce budworm in northeastern North America

NASA Astrophysics Data System (ADS)

Irland, Lloyd C.

1980-09-01

The eastern spruce budworm is a major forest pest over the continental range of the spruce-fir forest ecosystem and its southern ecotonal fringes in Canada and the northeastern United States. The current budworm outbreak illustrates the difficulty of arriving at economically sound and publicly acceptable forest pest control policies. Policies ranging from no use of chemical control to annual widespread crop protection have been adopted. There is no single all-around “best” policy for spruce budworm control. Chemical spray programs have demonstrably slowed the normal progress of mortality due to budworm, but have not eradicated the pest. Where industry remains heavily dependent on a fully utilized spruce-fir forest, no easy, low-cost solutions to the budworm problem exist. Reliance on spraying will have to be reduced and plans made to utilize higher levels of tree mortality and to manage the forest for lower future vulnerability.

Robust Learning Control Design for Quantum Unitary Transformations.

PubMed

Wu, Chengzhi; Qi, Bo; Chen, Chunlin; Dong, Daoyi

2017-12-01

Robust control design for quantum unitary transformations has been recognized as a fundamental and challenging task in the development of quantum information processing due to unavoidable decoherence or operational errors in the experimental implementation of quantum operations. In this paper, we extend the systematic methodology of sampling-based learning control (SLC) approach with a gradient flow algorithm for the design of robust quantum unitary transformations. The SLC approach first uses a "training" process to find an optimal control strategy robust against certain ranges of uncertainties. Then a number of randomly selected samples are tested and the performance is evaluated according to their average fidelity. The approach is applied to three typical examples of robust quantum transformation problems including robust quantum transformations in a three-level quantum system, in a superconducting quantum circuit, and in a spin chain system. Numerical results demonstrate the effectiveness of the SLC approach and show its potential applications in various implementation of quantum unitary transformations.

Optical Control of a Nuclear Spin in Diamond

NASA Astrophysics Data System (ADS)

Levonian, David; Goldman, Michael; Degreve, Kristiaan; Choi, Soonwon; Markham, Matthew; Twitchen, Daniel; Lukin, Mikhail

2017-04-01

The nitrogen-vacancy (NV) center in diamond has emerged as a promising candidate for quantum information and quantum communication applications. The NV center's potential as a quantum register is due to the long coherence time of its spin-triplet electronic ground state, the optical addressability of its electronic transitions, and the presence of nearby ancillary nuclear spins. The NV center's electronic spin and nearby nuclear spins are most commonly manipulated using applied microwave and RF fields, but this approach would be difficult to scale up for use with an array of NV-based quantum registers. In this context, all-optical manipulation would be more scalable, technically simpler, and potentially faster. Although all-optical control of the electronic spin has been demonstrated, it is an outstanding problem for the nuclear spins. Here, we use an optical Raman scheme to implement nuclear spin-specific control of the electronic spin and coherent control of the 14N nuclear spin.

Incremental validity of estimated cannabis grams as a predictor of problems and cannabinoid biomarkers: Evidence from a clinical trial.

PubMed

Tomko, Rachel L; Baker, Nathaniel L; McClure, Erin A; Sonne, Susan C; McRae-Clark, Aimee L; Sherman, Brian J; Gray, Kevin M

2018-01-01

Quantifying cannabis use is complex due to a lack of a standardized packaging system that contains specified amounts of constituents. A laboratory procedure has been developed for estimating physical quantity of cannabis use by utilizing a surrogate substance to represent cannabis, and weighing the amount of the surrogate to determine typical use in grams. This secondary analysis utilized data from a multi-site, randomized, controlled pharmacological trial for adult cannabis use disorder (N=300), sponsored by the National Drug Abuse Treatment Clinical Trials Network, to test the incremental validity of this procedure. In conjunction with the Timeline Followback, this physical scale-based procedure was used to determine whether average grams per cannabis administration predicted urine cannabinoid levels (11-nor-9-carboxy-Δ9-tetrahydrocannabinol) and problems due to use, after accounting for self-reported number of days used (in the past 30 days) and number of administrations per day in a 12-week clinical trial for cannabis use disorder. Likelihood ratio tests suggest that model fit was significantly improved when grams per administration and relevant interactions were included in the model predicting urine cannabinoid level (X 2 =98.3; p<0.05) and in the model predicting problems due to cannabis use (X 2 =6.4; p<0.05), relative to a model that contained only simpler measures of quantity and frequency. This study provides support for the use of a scale-based method for quantifying cannabis use in grams. This methodology may be useful when precise quantification is necessary (e.g., measuring reduction in use in a clinical trial). Copyright © 2017 Elsevier B.V. All rights reserved.

Return to work after vocational rehabilitation for sick-listed workers with long-term back, neck and shoulder problems: A follow-up study of factors involved.

PubMed

Rinaldo, Ulrika; Selander, John

2016-09-27

Absence from work due to musculoskeletal disorders is a significant problem from a number of perspectives, and there is a great need to identify factors that facilitate return to work (RTW). To identify factors related to RTW after vocational rehabilitation for sick-listed workers with long-term back, neck and/or shoulder problems, and to compare the results with those from a previous literature review based on studies from 1980 to 2000. A literature review based on studies published 2001-2014 in PubMed, CINAHL, EMBASE, ERIC and the Cochrane Library. Major risk factors for not returning to work are: higher age, factors related to pain such as higher levels of pain and pain related fear, avoidance of activity, high distress and depression. Facilitating factors for RTW are: lower functional disability, gaining control over one's own condition, believing in RTW and work-related factors such as occupational training, and having a job coach or an RTW coordinator. Compared with the results from the previous review, the present review shows less of a focus on sociodemographic factors and more on psychological factors. Both studies highlight risk factors such as older age, higher levels of pain, depression and less internal locus of control. Psychosocial and work-related factors are important and should be included in interventions for the RTW of people with long-term back, neck and/or shoulder problems.

Instantaneous and controllable integer ambiguity resolution: review and an alternative approach

NASA Astrophysics Data System (ADS)

Zhang, Jingyu; Wu, Meiping; Li, Tao; Zhang, Kaidong

2015-11-01

In the high-precision application of Global Navigation Satellite System (GNSS), integer ambiguity resolution is the key step to realize precise positioning and attitude determination. As the necessary part of quality control, integer aperture (IA) ambiguity resolution provides the theoretical and practical foundation for ambiguity validation. It is mainly realized by acceptance testing. Due to the constraint of correlation between ambiguities, it is impossible to realize the controlling of failure rate according to analytical formula. Hence, the fixed failure rate approach is implemented by Monte Carlo sampling. However, due to the characteristics of Monte Carlo sampling and look-up table, we have to face the problem of a large amount of time consumption if sufficient GNSS scenarios are included in the creation of look-up table. This restricts the fixed failure rate approach to be a post process approach if a look-up table is not available. Furthermore, if not enough GNSS scenarios are considered, the table may only be valid for a specific scenario or application. Besides this, the method of creating look-up table or look-up function still needs to be designed for each specific acceptance test. To overcome these problems in determination of critical values, this contribution will propose an instantaneous and CONtrollable (iCON) IA ambiguity resolution approach for the first time. The iCON approach has the following advantages: (a) critical value of acceptance test is independently determined based on the required failure rate and GNSS model without resorting to external information such as look-up table; (b) it can be realized instantaneously for most of IA estimators which have analytical probability formulas. The stronger GNSS model, the less time consumption; (c) it provides a new viewpoint to improve the research about IA estimation. To verify these conclusions, multi-frequency and multi-GNSS simulation experiments are implemented. Those results show that IA estimators based on iCON approach can realize controllable ambiguity resolution. Besides this, compared with ratio test IA based on look-up table, difference test IA and IA least square based on the iCON approach most of times have higher success rates and better controllability to failure rates.

An investigation into the design and performance of an automatic shape control system for a Sendzimir cold rolling mill

NASA Astrophysics Data System (ADS)

Dutton, Kenneth

Shape (or flatness) control for rolled steel strip is becoming increasingly important as customer requirements become more stringent. Automatic shape control is now more or less mandatory on all new four-high cold mills, but no comprehensive scheme yet exists on a Sendzimir mill. This is due to the complexity of the control system design on such a mill, where many more degrees of freedom for control exist than is the case with the four-high mills.The objective of the current work is to develop, from first principles, such a system; including automatic control of the As-U-Roll and first intermediate roll actuators in response to the measured strip shape. This thesis concerns itself primarily with the As-U-Roll control system. The material presented is extremely wide-ranging. Areas covered include the development of original static and dynamic mathematical models of the mill systems, and testing of the plant by data-logging to tune these models. A basic control system philosophy proposed by other workers is modified and developed to suit the practical system requirements and the data provided by the models. The control strategy is tested by comprehensive multivariable simulation studies. Finally, details are given of the practical problems faced when installing the system on the plant. These include problems of manual control inter-action bumpless transfer and integral desaturation.At the time of presentation of the thesis, system commissioning is still in progress and production results are therefore not yet available. Nevertheless, the simulation studies predict a successful outcome, although performance is expected to be limited until the first intermediate roll actuators are eventually included in the scheme also.

Universal approximators for multi-objective direct policy search in water reservoir management problems: a comparative analysis

NASA Astrophysics Data System (ADS)

Giuliani, Matteo; Mason, Emanuele; Castelletti, Andrea; Pianosi, Francesca

2014-05-01

The optimal operation of water resources systems is a wide and challenging problem due to non-linearities in the model and the objectives, high dimensional state-control space, and strong uncertainties in the hydroclimatic regimes. The application of classical optimization techniques (e.g., SDP, Q-learning, gradient descent-based algorithms) is strongly limited by the dimensionality of the system and by the presence of multiple, conflicting objectives. This study presents a novel approach which combines Direct Policy Search (DPS) and Multi-Objective Evolutionary Algorithms (MOEAs) to solve high-dimensional state and control space problems involving multiple objectives. DPS, also known as parameterization-simulation-optimization in the water resources literature, is a simulation-based approach where the reservoir operating policy is first parameterized within a given family of functions and, then, the parameters optimized with respect to the objectives of the management problem. The selection of a suitable class of functions to which the operating policy belong to is a key step, as it might restrict the search for the optimal policy to a subspace of the decision space that does not include the optimal solution. In the water reservoir literature, a number of classes have been proposed. However, many of these rules are based largely on empirical or experimental successes and they were designed mostly via simulation and for single-purpose reservoirs. In a multi-objective context similar rules can not easily inferred from the experience and the use of universal function approximators is generally preferred. In this work, we comparatively analyze two among the most common universal approximators: artificial neural networks (ANN) and radial basis functions (RBF) under different problem settings to estimate their scalability and flexibility in dealing with more and more complex problems. The multi-purpose HoaBinh water reservoir in Vietnam, accounting for hydropower production and flood control, is used as a case study. Preliminary results show that the RBF policy parametrization is more effective than the ANN one. In particular, the approximated Pareto front obtained with RBF control policies successfully explores the full tradeoff space between the two conflicting objectives, while most of the ANN solutions results to be Pareto-dominated by the RBF ones.

Prevalence and Mental Health Correlates of Harassment and Discrimination in the Workplace: Results from a National Study

PubMed Central

Rospenda, Kathleen M.; Richman, Judith A.; Shannon, Candice A.

2014-01-01

This study describes past-year prevalence and effects on mental health and drinking outcomes for harassment and discrimination in the workplace (HDW) in a nationally-representative random-digit dial phone survey conducted in 2003–2004 (n=2,151). HDW measures included experiences and perceptions of sexual harassment and generalized workplace harassment, and perceived harassment or discrimination due to race/ethnicity. Prevalence was examined by sex, race, age, occupation, marital status, and education. Effects of HDW were assessed controlling for demographics and job and life stressors. Experiencing multiple types of HDW was common. Sexual harassment was more prevalent among women, and Blacks and those of other or mixed race/ethnicity experienced the highest levels of HDW overall. HDW variables explained additional variance in problem drinking and mental health beyond life and job stressors, particularly for women. This study demonstrates that HDW is a prevalent problem associated with poor mental health and problem drinking in the U.S. workforce. PMID:18463311

On the stress singularities generated by anisotropic eigenstrains and the hydrostatic stress due to annular inhomogeneities

NASA Astrophysics Data System (ADS)

Yavari, Arash; Goriely, Alain

2015-03-01

The problems of singularity formation and hydrostatic stress created by an inhomogeneity with eigenstrain in an incompressible isotropic hyperelastic material are considered. For both a spherical ball and a cylindrical bar with a radially symmetric distribution of finite possibly anisotropic eigenstrains, we show that the anisotropy of these eigenstrains at the center (the center of the sphere or the axis of the cylinder) controls the stress singularity. If they are equal at the center no stress singularity develops but if they are not equal then stress always develops a logarithmic singularity. In both cases, the energy density and strains are everywhere finite. As a related problem, we consider annular inclusions for which the eigenstrains vanish in a core around the center. We show that even for an anisotropic distribution of eigenstrains, the stress inside the core is always hydrostatic. We show how these general results are connected to recent claims on similar problems in the limit of small eigenstrains.

Integration of the Response Surface Methodology with the Compromise Decision Support Problem in Developing a General Robust Design Procedure

NASA Technical Reports Server (NTRS)

Chen, Wei; Tsui, Kwok-Leung; Allen, Janet K.; Mistree, Farrokh

1994-01-01

In this paper we introduce a comprehensive and rigorous robust design procedure to overcome some limitations of the current approaches. A comprehensive approach is general enough to model the two major types of robust design applications, namely, robust design associated with the minimization of the deviation of performance caused by the deviation of noise factors (uncontrollable parameters), and robust design due to the minimization of the deviation of performance caused by the deviation of control factors (design variables). We achieve mathematical rigor by using, as a foundation, principles from the design of experiments and optimization. Specifically, we integrate the Response Surface Method (RSM) with the compromise Decision Support Problem (DSP). Our approach is especially useful for design problems where there are no closed-form solutions and system performance is computationally expensive to evaluate. The design of a solar powered irrigation system is used as an example. Our focus in this paper is on illustrating our approach rather than on the results per se.

Inverse dynamics of a 3 degree of freedom spatial flexible manipulator

NASA Technical Reports Server (NTRS)

Bayo, Eduardo; Serna, M.

1989-01-01

A technique is presented for solving the inverse dynamics and kinematics of 3 degree of freedom spatial flexible manipulator. The proposed method finds the joint torques necessary to produce a specified end effector motion. Since the inverse dynamic problem in elastic manipulators is closely coupled to the inverse kinematic problem, the solution of the first also renders the displacements and rotations at any point of the manipulator, including the joints. Furthermore the formulation is complete in the sense that it includes all the nonlinear terms due to the large rotation of the links. The Timoshenko beam theory is used to model the elastic characteristics, and the resulting equations of motion are discretized using the finite element method. An iterative solution scheme is proposed that relies on local linearization of the problem. The solution of each linearization is carried out in the frequency domain. The performance and capabilities of this technique are tested through simulation analysis. Results show the potential use of this method for the smooth motion control of space telerobots.

Large-angle slewing maneuvers for flexible spacecraft

NASA Technical Reports Server (NTRS)

Chun, Hon M.; Turner, James D.

1988-01-01

A new class of closed-form solutions for finite-time linear-quadratic optimal control problems is presented. The solutions involve Potter's solution for the differential matrix Riccati equation, which assumes the form of a steady-state plus transient term. Illustrative examples are presented which show that the new solutions are more computationally efficient than alternative solutions based on the state transition matrix. As an application of the closed-form solutions, the neighboring extremal path problem is presented for a spacecraft retargeting maneuver where a perturbed plant with off-nominal boundary conditions now follows a neighboring optimal trajectory. The perturbation feedback approach is further applied to three-dimensional slewing maneuvers of large flexible spacecraft. For this problem, the nominal solution is the optimal three-dimensional rigid body slew. The perturbation feedback then limits the deviations from this nominal solution due to the flexible body effects. The use of frequency shaping in both the nominal and perturbation feedback formulations reduces the excitation of high-frequency unmodeled modes. A modified Kalman filter is presented for estimating the plant states.

Gender differences in 16-year trends in assault- and police-related problems due to drinking.

PubMed

Timko, Christine; Moos, Bernice S; Moos, Rudolf H

2009-09-01

This study examined the frequency and predictors of physical assault and having trouble with the police due to drinking over 16 years among women and men who, at baseline, were untreated for their alcohol use disorder. Predictors examined were the personal characteristics of impulsivity, self-efficacy, and problem-solving and emotional-discharge coping, as well as outpatient treatment and Alcoholics Anonymous (AA) participation. Women and men were similar on rates of perpetrating assault due to drinking, but men were more likely to have had trouble with the police due to drinking. Respondents who, at baseline, were more impulsive and relied more on emotional discharge coping, and less on problem-solving coping, assaulted others more frequently during the first year of follow-up. Similarly, less problem-solving coping at baseline was related to having had trouble with the police more often at one and 16 years due to drinking. The association between impulsivity and more frequent assault was stronger for women, whereas associations of self-efficacy and problem-solving coping with less frequent assault and police trouble were stronger for men. Participation in AA was also associated with a lower likelihood of having trouble with the police at one year, especially for men. Interventions aimed at decreasing impulsivity and emotional discharge coping, and bolstering self-efficacy and problem-solving coping, during substance abuse treatment, and encouragement to become involved in AA, may be helpful in reducing assaultive and other illegal behaviors.

Randomly Sampled-Data Control Systems. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Han, Kuoruey

1990-01-01

The purpose is to solve the Linear Quadratic Regulator (LQR) problem with random time sampling. Such a sampling scheme may arise from imperfect instrumentation as in the case of sampling jitter. It can also model the stochastic information exchange among decentralized controllers to name just a few. A practical suboptimal controller is proposed with the nice property of mean square stability. The proposed controller is suboptimal in the sense that the control structure is limited to be linear. Because of i. i. d. assumption, this does not seem unreasonable. Once the control structure is fixed, the stochastic discrete optimal control problem is transformed into an equivalent deterministic optimal control problem with dynamics described by the matrix difference equation. The N-horizon control problem is solved using the Lagrange's multiplier method. The infinite horizon control problem is formulated as a classical minimization problem. Assuming existence of solution to the minimization problem, the total system is shown to be mean square stable under certain observability conditions. Computer simulations are performed to illustrate these conditions.

Digital Control Technologies for Modular DC-DC Converters

NASA Technical Reports Server (NTRS)

Button, Robert M.; Kascak, Peter E.; Lebron-Velilla, Ramon

2002-01-01

Recent trends in aerospace Power Management and Distribution (PMAD) systems focus on using commercial off-the-shelf (COTS) components as standard building blocks. This move to more modular designs has been driven by a desire to reduce costs and development times, but is also due to the impressive power density and efficiency numbers achieved by today's commercial DC-DC converters. However, the PMAD designer quickly learns of the hidden "costs" of using COTS converters. The most significant cost is the required addition of external input filters to meet strict electromagnetic interference (MIAMI) requirements for space systems. In fact, the high power density numbers achieved by the commercial manufacturers are greatly due to the lack of necessary input filters included in the COTS module. The NASA Glenn Research Center is currently pursuing a digital control technology that addresses this problem with modular DC-DC converters. This paper presents the digital control technologies that have been developed to greatly reduce the input filter requirements for paralleled, modular DC-DC converters. Initial test result show that the input filter's inductor size was reduced by 75 percent, and the capacitor size was reduced by 94 percent while maintaining the same power quality specifications.

Erythema Nodosum Leprosum: Update and challenges on the treatment of a neglected condition.

PubMed

Costa, Perpétua do Socorro Silva; Fraga, Lucas Rosa; Kowalski, Thayne Woycinck; Daxbacher, Egon Luiz Rodrigues; Schuler-Faccini, Lavínia; Vianna, Fernanda Sales Luiz

2018-07-01

Erythema Nodosum Leprosum (ENL) occurs due to the immunological complication of multibacillary leprosy and is characterized by painful nodules and systemic compromising. It is usually recurrent and/or chronic and has both physical and economic impact on the patient, being a very important cause of disability. In addition, ENL is a major health problem in countries where leprosy is endemic. Therefore, adequate control of this condition is important. The management of ENL aims to control acute inflammation and neuritis and prevent the onset of new episodes. However, all currently available treatment modalities have one or two drawbacks and are not effective for all patients. Corticosteroid is the anti-inflammatory of choice in ENL but may cause dependence, especially for chronic patients. Thalidomide has a rapid action but its use is limited due the teratogenicity and neurotoxicity. Clofazimine and pentoxifylline have slow action and have important adverse effects. Finally, there is no pattern or guidelines for treating these patients, becoming more difficult to evaluate and to control this condition. This review aims to show the main drugs used in the treatment of ENL and the challenges in the management of the reaction. Copyright © 2018 Elsevier B.V. All rights reserved.

Personal cooling in hot workings

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

Tuck, M.A.

1999-07-01

The number of mines experiencing climatic difficulties worldwide is increasing. In a large number of cases these climatic difficulties are confined to working areas only or to specific locations within working areas. Thus the problem in these mines can be described as highly localized, due to a large extent not to high rock temperatures but due to machine heat loads and low airflow rates. Under such situations conventional means of controlling the climate can be inapplicable and/or uneconomic. One possible means of achieving the required level of climatic control, to ensure worker health and safety whilst achieving economic gains, ismore » to adopt a system of active man cooling. This is the reverse of normal control techniques where the cooling power of the ventilating air is enhanced in some way. Current methods of active man cooling include ice jackets and various umbilical cord type systems. These have numerous drawbacks, such as limited useful exposure times and limitations to worker mobility. The paper suggests an alternative method of active man cooling than those currently available and reviews the design criteria for such a garment. The range of application of such a garment is discussed, under both normal and emergency situations.« less

Discomfort analysis in computerized numeric control machine operations.

PubMed

Muthukumar, Krishnamoorthy; Sankaranarayanasamy, Krishnasamy; Ganguli, Anindya Kumar

2012-06-01

The introduction of computerized numeric control (CNC) technology in manufacturing industries has revolutionized the production process, but there are some health and safety problems associated with these machines. The present study aimed to investigate the extent of postural discomfort in CNC machine operators, and the relationship of this discomfort to the display and control panel height, with a view to validate the anthropometric recommendation for the location of the display and control panel in CNC machines. The postural discomforts associated with CNC machines were studied in 122 male operators using Corlett and Bishop's body part discomfort mapping, subject information, and discomfort level at various time intervals from starting to end of a shift. This information was collected using a questionnaire. Statistical analysis was carried out using ANOVA. Neck discomfort due to the positioning of the machine displays, and shoulder and arm discomfort due to the positioning of controls were identified as common health issues in the operators of these machines. The study revealed that 45.9% of machine operators reported discomfort in the lower back, 41.8% in the neck, 22.1% in the upper-back, 53.3% in the shoulder and arm, and 21.3% of the operators reported discomfort in the leg. Discomfort increased with the progress of the day and was highest at the end of a shift; subject age had no effect on patient tendency to experience discomfort levels.

Mission Analysis and Orbit Control of Interferometric Wheel Formation Flying

NASA Astrophysics Data System (ADS)

Fourcade, J.

Flying satellite in formation requires maintaining the specific relative geometry of the spacecraft with high precision. This requirement raises new problem of orbit control. This paper presents the results of the mission analysis of a low Earth observation system, the interferometric wheel, patented by CNES. This wheel is made up of three receiving spacecraft, which follow an emitting Earth observation radar satellite. The first part of this paper presents trades off which were performed to choose orbital elements of the formation flying which fulfils all constraints. The second part presents orbit positioning strategies including reconfiguration of the wheel to change its size. The last part describes the station keeping of the formation. Two kinds of constraints are imposed by the interferometric system : a constraint on the distance between the wheel and the radar satellite, and constraints on the distance between the wheel satellites. The first constraint is fulfilled with a classical chemical station keeping strategy. The second one is fulfilled using pure passive actuators. Due to the high stability of the relative eccentricity of the formation, only the relative semi major axis had to be controlled. Differential drag due to differential attitude motion was used to control relative altitude. An autonomous orbit controller was developed and tested. The final accuracy is a relative station keeping better than few meters for a wheel size of one kilometer.

Discomfort Analysis in Computerized Numeric Control Machine Operations

PubMed Central

Sankaranarayanasamy, Krishnasamy; Ganguli, Anindya Kumar

2012-01-01

Objectives The introduction of computerized numeric control (CNC) technology in manufacturing industries has revolutionized the production process, but there are some health and safety problems associated with these machines. The present study aimed to investigate the extent of postural discomfort in CNC machine operators, and the relationship of this discomfort to the display and control panel height, with a view to validate the anthropometric recommendation for the location of the display and control panel in CNC machines. Methods The postural discomforts associated with CNC machines were studied in 122 male operators using Corlett and Bishop's body part discomfort mapping, subject information, and discomfort level at various time intervals from starting to end of a shift. This information was collected using a questionnaire. Statistical analysis was carried out using ANOVA. Results Neck discomfort due to the positioning of the machine displays, and shoulder and arm discomfort due to the positioning of controls were identified as common health issues in the operators of these machines. The study revealed that 45.9% of machine operators reported discomfort in the lower back, 41.8% in the neck, 22.1% in the upper-back, 53.3% in the shoulder and arm, and 21.3% of the operators reported discomfort in the leg. Conclusion Discomfort increased with the progress of the day and was highest at the end of a shift; subject age had no effect on patient tendency to experience discomfort levels. PMID:22993720

The effectiveness of the "Brainwork Intervention" in reducing sick leave for unemployed workers with psychological problems: design of a controlled clinical trial.

PubMed

Audhoe, Selwin S; Nieuwenhuijsen, Karen; Hoving, Jan L; Sluiter, Judith K; Frings-Dresen, Monique H W

2015-04-14

Among the working population, unemployed, temporary agency and expired fixed-term contract workers having psychological problems are a particularly vulnerable group, at risk for sickness absence and prolonged work disability. Studies investigating the effectiveness of return-to-work (RTW) interventions on these workers, who are without an employment contract, are scarce. Therefore, a RTW intervention called 'Brainwork' was developed. The objective of this paper is to describe the 'Brainwork Intervention' and the trial design evaluating its effectiveness in reducing the duration of sick leave compared to usual care. The 'Brainwork Intervention' is designed to assist unemployed, temporary agency and expired fixed-term contract workers who are sick-listed due to psychological problems, with their return to work. The 'Brainwork Intervention' uses an activating approach: in the early stage of sick leave, workers are encouraged to exercise and undertake activities aimed at regaining control and functional recovery while job coaches actively support their search for (temporary) jobs. The content of the intervention is tailored to the severity of the psychological problems and functional impairments, as well as the specific psychosocial problems encountered by the sick-listed worker. The intervention study is designed as a quasi-randomized controlled clinical trial with a one-year follow-up and is being conducted in the Netherlands. The control group receives care as usual with minimal involvement of occupational health professionals. Outcomes are measured at baseline, and 4, 8 and 12 months after initiation of the program. The primary outcome measure is the duration of sick leave. Secondary outcome measures are: the proportion of subjects who returned to work at 8 and 12 months; the number of days of paid employment during the follow-up period; the degree of worker participation; the level of psychological complaints; and the self-efficacy for return to work. The cost-benefit analysis will be evaluated from an insurer's perspective. The methodological considerations of the study design are discussed. In this trial we evaluate the effectiveness of an intervention in real occupational health practice, rather than under highly controlled circumstances. The results will be published in 2015. NTR4190. Date of registration: September 27(th) 2013.

Psychoanalytic peregrinations. III: Confusion of tongues, psychoanalyst as translator.

PubMed

Chessick, Richard D

2002-01-01

A variety of problems cause a confusion of tongues between the psychoanalyst and the patient. In this sense the psychoanalyst faces the same problems as the translator of a text from one language to another. Examples are given of confusion due cultural differences, confusion due translation differences among translators, confusion due translator prejudice or ignorance, confusion due ambiguous visual cues and images, and confusion due to an inherently ambiguous text. It is due to this unavoidable confusion that the humanistic sciences cannot in principle achieve the mathematical exactness of the natural sciences and should not be expected to do so or condemned because they do not.

Risk Factors for Fatal Hyperglycaemia Confirmed by Forensic Postmortem Examination - A Nationwide Cohort in Sweden.

PubMed

Walz, Lotta; Jönsson, Anna K; Zilg, Brita; Östgren, Carl Johan; Druid, Henrik

2016-01-01

The aim of this study was to identify risk factors associated with confirmed fatal hyperglycaemia, which could predispose potentially preventable deaths in individuals on glucose lowering drugs. A retrospective register-based case-control study conducted on a nationwide cohort with individuals who died due to hyperglycaemia as determined by forensic postmortem examination, in Sweden August 2006 to December 2012. Vitreous glucose was used to diagnose hyperglycaemia postmortem. The forensic findings stored in the National Forensic Medicine Database were linked to nationwide registers. Cases that died due to confirmed hyperglycemia with dispensed glucose lowering drugs were identified and living controls with dispensed glucose lowering drugs were randomly selected in the Swedish prescribed drug register and matched on age and sex. Information on comorbidities, dispensed pharmaceuticals, clinical data and socioeconomic factors were obtained for cases and controls. Adjusted multiple logistic regression models were used to identify risk factors associated with fatal hyperglycaemia. During the study period 322 individuals, mostly males (79%) with the mean age of 53.9 years (SD.± 14) died due to confirmed hyperglycaemia. Risk factors for fatal hyperglycaemia included; insulin treatment (OR = 4.40; 95%CI,1.96, 9.85), poor glycaemic control (OR = 2.00 95%CI,1.23, 3.27), inadequate refill-adherence before death (OR = 3.87; 95%CI,1.99, 7.53), microvascular disease (OR = 3.26; 95% CI, 1.84, 5.79), psychiatric illness (OR = 2.30; 95% CI,1.32, 4.01), substance abuse (OR = 8.85; 95%CI,2.34, 35.0) and/or living alone (OR = 2.25; 95%CI,1.21, 4.18). Our results demonstrate the importance of clinical attention to poor glycaemic control in subjects with psychosocial problems since it may indicate serious non-adherence, which consequently could lead to fatal hyperglycaemia.

Quality of Life Over Time in Women Diagnosed with Ductal Carcinoma In situ, Early-Stage Invasive Breast Cancer, and Age-Matched Controls

PubMed Central

Jeffe, DB; Pérez, M; Liu, Y; Collins, KK; Aft, RL; Schootman, M

2012-01-01

Little is known about quality-of-life (QOL) differences over time between incident ductal carcinoma in situ (DCIS) and early-stage invasive breast cancer (EIBC) cases as compared with same-aged women without breast cancer (controls). We prospectively recruited and interviewed 1096 women (16.8% DCIS, 33.3% EIBC [25.7% Stage I, 7.6% Stage IIA], 49.9% controls; mean age 58; 23.7% non-white) a mean 6.7 weeks (T1), and 6.2 (T2), 12.3 (T3), and 24.4 months (T4) after surgery (patients) or screening mammogram (controls). We tested two hypotheses: (1) DCIS patients would report lower levels of QOL compared with controls but would report similar QOL compared with EIBC patients at baseline; and (2) DCIS patients’ QOL would improve during 2-year follow-up and approach levels similar to that of controls faster than EIBC patients. We tested Hypothesis 1 using separate general linear regression models for each of the eight subscales on the RAND 36-item Health Survey, controlling for variables associated with at least one subscale at T1. Both DCIS and EIBC patients reported lower QOL at T1 than controls on all subscales (each p < .05). We tested Hypothesis 2 using generalized estimating equations to examine change in each QOL subscale over time across the three diagnostic groups adjusting for covariates. By T3, physical functioning, role limitations due to physical problems, energy/fatigue, and general health each differed significantly by diagnostic group at P < 0.05, due to larger differences between EIBC patients and controls; but DCIS patients no longer differed significantly from controls on any of the QOL subscales. At T4, EIBC patients still reported worse physical functioning (P = 0.0001) and general health (P = 0.0017) than controls, possibly due to lingering treatment effects. DCIS patients’ QOL was similar to that of controls two years after diagnosis, but some aspects of EIBC patients’ QOL remained lower. PMID:22484800

New numerical methods for open-loop and feedback solutions to dynamic optimization problems

NASA Astrophysics Data System (ADS)

Ghosh, Pradipto

The topic of the first part of this research is trajectory optimization of dynamical systems via computational swarm intelligence. Particle swarm optimization is a nature-inspired heuristic search method that relies on a group of potential solutions to explore the fitness landscape. Conceptually, each particle in the swarm uses its own memory as well as the knowledge accumulated by the entire swarm to iteratively converge on an optimal or near-optimal solution. It is relatively straightforward to implement and unlike gradient-based solvers, does not require an initial guess or continuity in the problem definition. Although particle swarm optimization has been successfully employed in solving static optimization problems, its application in dynamic optimization, as posed in optimal control theory, is still relatively new. In the first half of this thesis particle swarm optimization is used to generate near-optimal solutions to several nontrivial trajectory optimization problems including thrust programming for minimum fuel, multi-burn spacecraft orbit transfer, and computing minimum-time rest-to-rest trajectories for a robotic manipulator. A distinct feature of the particle swarm optimization implementation in this work is the runtime selection of the optimal solution structure. Optimal trajectories are generated by solving instances of constrained nonlinear mixed-integer programming problems with the swarming technique. For each solved optimal programming problem, the particle swarm optimization result is compared with a nearly exact solution found via a direct method using nonlinear programming. Numerical experiments indicate that swarm search can locate solutions to very great accuracy. The second half of this research develops a new extremal-field approach for synthesizing nearly optimal feedback controllers for optimal control and two-player pursuit-evasion games described by general nonlinear differential equations. A notable revelation from this development is that the resulting control law has an algebraic closed-form structure. The proposed method uses an optimal spatial statistical predictor called universal kriging to construct the surrogate model of a feedback controller, which is capable of quickly predicting an optimal control estimate based on current state (and time) information. With universal kriging, an approximation to the optimal feedback map is computed by conceptualizing a set of state-control samples from pre-computed extremals to be a particular realization of a jointly Gaussian spatial process. Feedback policies are computed for a variety of example dynamic optimization problems in order to evaluate the effectiveness of this methodology. This feedback synthesis approach is found to combine good numerical accuracy with low computational overhead, making it a suitable candidate for real-time applications. Particle swarm and universal kriging are combined for a capstone example, a near optimal, near-admissible, full-state feedback control law is computed and tested for the heat-load-limited atmospheric-turn guidance of an aeroassisted transfer vehicle. The performance of this explicit guidance scheme is found to be very promising; initial errors in atmospheric entry due to simulated thruster misfirings are found to be accurately corrected while closely respecting the algebraic state-inequality constraint.

Corticolimbic structural alterations linked to health status and trait anxiety in functional neurological disorder.

PubMed

Perez, David L; Williams, Benjamin; Matin, Nassim; LaFrance, W Curt; Costumero-Ramos, Victor; Fricchione, Gregory L; Sepulcre, Jorge; Keshavan, Matcheri S; Dickerson, Bradford C

2017-12-01

Affective symptoms influence health status (health-related quality of life) in functional neurological disorder (FND), and the salience network is implicated in the pathophysiology of FND and mood/anxiety disorders. We hypothesised that self-reported health status and affective symptoms would map onto salience network regions and that patients with FND would show decreased insular volumes compared with controls. This voxel-based morphometry study investigated volumetric differences in 26 patients with FND (21 women, 5 men; mean age=40.3±11.5) compared with 27 healthy controls (22 women, 5 men; mean age=40.5±10.8). Post hoc analyses stratified patients with FND by mental and physical health scores (Short Form Health Survey-36). Within-group analyses investigated associations with mental health, physical health, trait anxiety and depression in patients with FND. There were no volumetric differences between the complete FND cohort and controls. In stratified analyses, however, patients with FND reporting the most severe physical health impairments showed reduced left anterior insular volume compared with controls. In within-group analyses, impaired mental health and elevated trait anxiety were associated with increased right amygdalar volumes in patients with FND. The relationship between amygdalar volume and mental health, driven by emotional well-being deficits and role limitations due to emotional problems, was independent of sensorimotor functional neurological symptom severity and motor FND subtype. In secondary within-group analyses, increased periaqueductal grey volume was associated with role limitations due to emotional problems. Impaired physical functioning correlated with decreased left anterior insular volumes. These findings support roles for several regions of the salience network in the pathophysiology of FND. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Quality control process improvement of flexible printed circuit board by FMEA

NASA Astrophysics Data System (ADS)

Krasaephol, Siwaporn; Chutima, Parames

2018-02-01

This research focuses on the quality control process improvement of Flexible Printed Circuit Board (FPCB), centred around model 7-Flex, by using Failure Mode and Effect Analysis (FMEA) method to decrease proportion of defective finished goods that are found at the final inspection process. Due to a number of defective units that were found at the final inspection process, high scraps may be escaped to customers. The problem comes from poor quality control process which is not efficient enough to filter defective products from in-process because there is no In-Process Quality Control (IPQC) or sampling inspection in the process. Therefore, the quality control process has to be improved by setting inspection gates and IPCQs at critical processes in order to filter the defective products. The critical processes are analysed by the FMEA method. IPQC is used for detecting defective products and reducing chances of defective finished goods escaped to the customers. Reducing proportion of defective finished goods also decreases scrap cost because finished goods incur higher scrap cost than work in-process. Moreover, defective products that are found during process can reflect the abnormal processes; therefore, engineers and operators should timely solve the problems. Improved quality control was implemented for 7-Flex production lines from July 2017 to September 2017. The result shows decreasing of the average proportion of defective finished goods and the average of Customer Manufacturers Lot Reject Rate (%LRR of CMs) equal to 4.5% and 4.1% respectively. Furthermore, cost saving of this quality control process equals to 100K Baht.

Prospective relationship between poor sleep and substance-related problems in a national sample of adolescents

PubMed Central

Wong, Maria M.; Roberson, Gail; Dyson, Rachel

2014-01-01

Background Previous studies showed that poor sleep prospectively predicted alcohol related problems and illicit drug use in adolescents and young adults (Wong et al., 2010, 2012). However, more works needs to be done to elucidate the nature of these problems. The purpose of this study was to examine whether sleep difficulties and hours of sleep prospectively predicted several serious substance related problems, e.g., binge drinking, driving under the influence of alcohol, risky sexual behavior. Methods Study participants were 6504 adolescents from the National Longitudinal Study of Adolescent Health (ADD HEALTH). Data were collected from interviews and questionnaires. The current study analyzed data from the first three waves of data (T1: 1994–95; T2: 1996; T3: 2001–02). In all analyses, we used sleep difficulties at a previous wave to predict substance-related problems at a subsequent wave, while controlling for substance-related problems at a previous wave. Results Holding T1 alcohol-related problems constant, sleep difficulties at T1 significantly predicted alcohol-related interpersonal problems, binge drinking, gotten drunk or very high on alcohol, driving under the influence of alcohol, getting into a sexual situation one later regretted due to drinking, ever using any illicit drugs and drugs-related problems at T2. T1 hours of sleep negatively predicted T2 alcohol-related interpersonal problems and binge drinking. The relationship between T2 sleep variables and T3 substance-related problems were consistent with previous waves, though the effect was weaker. Conclusions Sleep difficulties and hours of sleep are a significant predictor of a number of substance-related problems. It may be useful to educate adolescents about the importance of sleep, sleep hygiene and the potential consequences of poor sleep on drinking and related behaviors. PMID:25598438

Active Blade Vibration Control Being Developed and Tested

NASA Technical Reports Server (NTRS)

Johnson, Dexter

2003-01-01

Gas turbine engines are currently being designed to have increased performance, lower weight and manufacturing costs, and higher reliability. Consequently, turbomachinery components, such as turbine and compressor blades, have designs that are susceptible to new vibration problems and eventual in-service failure due to high-cycle fatigue. To address this problem, researchers at the NASA Glenn Research Center are developing and testing innovative active blade vibration control concepts. Preliminary results of using an active blade vibration control system, involving a rotor supported by an active magnetic bearing in Glenn's Dynamic Spin Rig, indicate promising results (see the photograph). Active blade vibration control was achieved using feedback of blade strain gauge signals within the magnetic bearing control loop. The vibration amplitude was reduced substantially (see the graphs). Also, vibration amplitude amplification was demonstrated; this could be used to enhance structural mode identification, if desired. These results were for a nonrotating two-bladed disk. Tests for rotating blades are planned. Current and future active blade vibration control research is planned to use a fully magnetically suspended rotor and smart materials. For the fully magnetically suspended rotor work, three magnetic bearings (two radial and one axial) will be used as actuators instead of one magnetic bearing. This will allow additional degrees of freedom to be used for control. For the smart materials work, control effectors located on and off the blade will be considered. Piezoelectric materials will be considered for on-the-blade actuation, and actuator placement on a stator vane, or other nearby structure, will be investigated for off-the-blade actuation. Initial work will focus on determining the feasibility of these methods by performing basic analysis and simple experiments involving feedback control.

Reuse of hydroponic waste solution.

PubMed

Kumar, Ramasamy Rajesh; Cho, Jae Young

2014-01-01

Attaining sustainable agriculture is a key goal in many parts of the world. The increased environmental awareness and the ongoing attempts to execute agricultural practices that are economically feasible and environmentally safe promote the use of hydroponic cultivation. Hydroponics is a technology for growing plants in nutrient solutions with or without the use of artificial medium to provide mechanical support. Major problems for hydroponic cultivation are higher operational cost and the causing of pollution due to discharge of waste nutrient solution. The nutrient effluent released into the environment can have negative impacts on the surrounding ecosystems as well as the potential to contaminate the groundwater utilized by humans for drinking purposes. The reuse of non-recycled, nutrient-rich hydroponic waste solution for growing plants in greenhouses is the possible way to control environmental pollution. Many researchers have successfully grown several plant species in hydroponic waste solution with high yield. Hence, this review addresses the problems associated with the release of hydroponic waste solution into the environment and possible reuse of hydroponic waste solution as an alternative resource for agriculture development and to control environmental pollution.

Evaluation of zero-order controlled release preparations of nifedipine tablet on dissolution test, together with cost benefit point of view.

PubMed

Sakurai, Miyuki; Naruto, Ikue; Matsuyama, Kenji

2008-05-01

Many generic drugs have been released to decrease medical expenses, but some problems have been reported with regard to bioavailability and safety. In this study, we compared three once-a-day controlled-release preparations of nifedipine by the dissolution test (one branded and two generic preparations). Although the two generic drugs were equivalent to the branded drug according to the criteria listed in the Japanese "Guideline for Bioequivalence Studies of Generic Products", there was still a possibility of problems arising. For example, side effects could be caused by a rapid increase in the blood level of nifedipine with one generic drug, while bioavailability might be inadequate with the other due to its small area under the concentration vs. time curve. When each drug was prescribed at a dosage of 20 mg once daily for two weeks, the difference in the copayment for the patient was only 10 yen. Accordingly, it is important for doctors and pharmacists to carefully consider whether such a slight difference in price is really a benefit for the patient.

Faux-Pas Test: A Proposal of a Standardized Short Version.

PubMed

Fernández-Modamio, Mar; Arrieta-Rodríguez, Marta; Bengochea-Seco, Rosario; Santacoloma-Cabero, Iciar; Gómez de Tojeiro-Roce, Juan; García-Polavieja, Bárbara; González-Fraile, Eduardo; Martín-Carrasco, Manuel; Griffin, Kim; Gil-Sanz, David

2018-06-26

Previous research on theory of mind suggests that people with schizophrenia have difficulties with complex mentalization tasks that involve the integration of cognition and affective mental states. One of the tools most commonly used to assess theory of mind is the Faux-Pas Test. However, it presents two main methodological problems: 1) the lack of a standard scoring system; 2) the different versions are not comparable due to a lack of information on the stories used. These methodological problems make it difficult to draw conclusions about performance on this test by people with schizophrenia. The aim of this study was to develop a reduced version of the Faux-Pas test with adequate psychometric properties. The test was administered to control and clinical groups. Interrater and test-retest reliability were analyzed for each story in order to select the set of 10 stories included in the final reduced version. The shortened version showed good psychometric properties for controls and patients: test-retest reliability of 0.97 and 0.78, inter-rater reliability of 0.95 and 0.87 and Cronbach's alpha of 0.82 and 0.72.

"It Was My Fault": Bullied Students' Causal and Controllable Attributions in Bullying Blogs.

PubMed

Danielson, Carly M; Emmers-Sommer, Tara M

2016-01-01

Student bullying is a growing and damaging social problem. The devastating outcomes bullied individuals often experience due to such treatment make understanding this phenomenon imperative. Utilizing Heider's (1958) attribution theory, this study explores how bullied students (n = 100) attribute locus of causality and controllability for their victimization in 5 bullying blogs. Findings from this investigation reveal that (a) male and female bloggers' causal and controllable attributions do not differ; (b) bloggers most often attribute blame to bullies, although a noteworthy portion also attribute internal causation; and (c) bloggers often attribute bullying as uncontrollable for several reasons. This study also identifies factors that influence shifts in negative attributions about bullying. These findings inform bullying programs with the hope of reducing destructive attribution formations that potentially lead to prolonged victimization and detrimental consequences.

Self-propulsion of a body with rigid surface and variable coefficient of lift in a perfect fluid

NASA Astrophysics Data System (ADS)

Ramodanov, Sergey M.; Tenenev, Valentin A.; Treschev, Dmitry V.

2012-11-01

We study the system of a 2D rigid body moving in an unbounded volume of incompressible, vortex-free perfect fluid which is at rest at infinity. The body is equipped with a gyrostat and a so-called Flettner rotor. Due to the latter the body is subject to a lifting force (Magnus effect). The rotational velocities of the gyrostat and the rotor are assumed to be known functions of time (control inputs). The equations of motion are presented in the form of the Kirchhoff equations. The integrals of motion are given in the case of piecewise continuous control. Using these integrals we obtain a (reduced) system of first-order differential equations on the configuration space. Then an optimal control problem for several types of the inputs is solved using genetic algorithms.

Study on ecological regulation of coastal plain sluice

NASA Astrophysics Data System (ADS)

Yu, Wengong; Geng, Bing; Yu, Huanfei; Yu, Hongbo

2018-02-01

Coastal plains are densely populated and economically developed, therefore their importance is self-evident. However, there are some problems related with water in coastal plains, such as low flood control capacity and severe water pollution. Due to complicated river network hydrodynamic force, changeable flow direction and uncertain flood concentration and propagation mechanism, it is rather difficult to use sluice scheduling to realize flood control and tackle water pollution. On the base of the measured hydrological data during once-in-a-century Fitow typhoon in 2013 in Yuyao city, by typical analysis, theoretical analysis and process simulation, some key technologies were researched systematically including plain river network sluice ecological scheduling, “one tide” flood control and drainage scheduling and ecological running water scheduling. In the end, single factor health diagnostic evaluation, unit hydrograph of plain water level and evening tide scheduling were put forward.

Implicit Multibody Penalty-BasedDistributed Contact.

PubMed

Xu, Hongyi; Zhao, Yili; Barbic, Jernej

2014-09-01

The penalty method is a simple and popular approach to resolving contact in computer graphics and robotics. Penalty-based contact, however, suffers from stability problems due to the highly variable and unpredictable net stiffness, and this is particularly pronounced in simulations with time-varying distributed geometrically complex contact. We employ semi-implicit integration, exact analytical contact gradients, symbolic Gaussian elimination and a SVD solver to simulate stable penalty-based frictional contact with large, time-varying contact areas, involving many rigid objects and articulated rigid objects in complex conforming contact and self-contact. We also derive implicit proportional-derivative control forces for real-time control of articulated structures with loops. We present challenging contact scenarios such as screwing a hexbolt into a hole, bowls stacked in perfectly conforming configurations, and manipulating many objects using actively controlled articulated mechanisms in real time.

Boundary element based multiresolution shape optimisation in electrostatics

NASA Astrophysics Data System (ADS)

Bandara, Kosala; Cirak, Fehmi; Of, Günther; Steinbach, Olaf; Zapletal, Jan

2015-09-01

We consider the shape optimisation of high-voltage devices subject to electrostatic field equations by combining fast boundary elements with multiresolution subdivision surfaces. The geometry of the domain is described with subdivision surfaces and different resolutions of the same geometry are used for optimisation and analysis. The primal and adjoint problems are discretised with the boundary element method using a sufficiently fine control mesh. For shape optimisation the geometry is updated starting from the coarsest control mesh with increasingly finer control meshes. The multiresolution approach effectively prevents the appearance of non-physical geometry oscillations in the optimised shapes. Moreover, there is no need for mesh regeneration or smoothing during the optimisation due to the absence of a volume mesh. We present several numerical experiments and one industrial application to demonstrate the robustness and versatility of the developed approach.

Prediction and control of slender-wing rock

NASA Technical Reports Server (NTRS)

Kandil, Osama A.; Salman, Ahmed A.

1992-01-01

The unsteady Euler equations and the Euler equations of rigid-body dynamics, both written in the moving frame of reference, are sequentially solved to simulate the limit-cycle rock motion of slender delta wings. The governing equations of the fluid flow and the dynamics of the present multidisciplinary problem are solved using an implicit, approximately-factored, central-difference-like, finite-volume scheme and a four-stage Runge-Kutta scheme, respectively. For the control of wing-rock motion, leading-edge flaps are forced to oscillate anti-symmetrically at prescribed frequency and amplitude, which are tuned in order to suppress the rock motion. Since the computational grid deforms due to the leading-edge flaps motion, the grid is dynamically deformed using the Navier-displacement equations. Computational applications cover locally-conical and three-dimensional solutions for the wing-rock simulation and its control.

Advanced control concepts. [trim solution for space shuttle

NASA Technical Reports Server (NTRS)

Hutton, M. F.; Friedland, B.

1973-01-01

The selection of a trim solution that provides the space shuttle with the highest level of performance and dynamic control in the presense of wind disturbances and bias torques due to misalignment of rocket engines is described. It was determined that engine gimballing is insufficient to provide control to trim the vehicle for headwind and sidewind disturbances, and that it is necessary to use aerodynamic surfaces in conjunction with engine gimballing to achieve trim. The algebraic equations for computing the trim solution were derived from the differential equations describing the motion of the vehicle by substituting the desired trim conditions. The general problem of showing how the trim equations are derived from the equations of motion and the mathematical forms of the performance criterion is discussed in detail, along with the general equations for studying the dynamic response of the trim solution.

Biodegradable braided poly(lactic-co-glycolic acid) urethral stent combined with dutasteride in the treatment of acute urinary retention due to benign prostatic enlargement: a pilot study.

PubMed

Kotsar, Andres; Isotalo, Taina; Juuti, Hanne; Mikkonen, Joonas; Leppiniemi, Jenni; Hänninen, Venla; Kellomäki, Minna; Talja, Martti; Tammela, Teuvo L J

2009-03-01

To evaluate, in a pilot study, the efficacy and safety of combining a braided poly(lactic-co-glycolic acid) (PLGA, a copolymer of l-lactide and glycolide) urethral stent and dutasteride in the treatment of acute urinary retention (AUR) due to benign prostatic enlargement (BPE). Ten men with AUR due to BPE were treated as outpatients. A biodegradable braided PLGA urethral stent was inserted into the prostatic urethra, using a specially designed insertion device under visual control. Dutasteride treatment was started and the patients were followed up for 3 months after insertion of the stents. In all patients the stents were placed successfully with the new insertion device. All men were able to void after inserting the stent. At 1 month five patients voided freely with a low residual urine volume (<150 mL), two voided but had a high residual urine volume and a suprapubic catheter was placed, and three needed a suprapubic or an indwelling catheter before 1 month, due to AUR or comorbidities. At 3 months five patients were voiding with no problems. We have developed a new and effective insertion device for biodegradable braided prostatic stents. The new braided-pattern stent overcomes the earlier problems of migration and sudden breakage into large particles associated with biodegradable spiral stents. However, the mechanical properties of the new stent need to be improved and tested in a longer follow-up. We consider that this new biodegradable braided-pattern urethral stent could provide a new option in the future treatment of AUR.

Prader-Willi Syndrome: Obesity due to Genomic Imprinting

PubMed Central

Butler, Merlin G

2011-01-01

Prader-Willi syndrome (PWS) is a complex neurodevelopmental disorder due to errors in genomic imprinting with loss of imprinted genes that are paternally expressed from the chromosome 15q11-q13 region. Approximately 70% of individuals with PWS have a de novo deletion of the paternally derived 15q11-q13 region in which there are two subtypes (i.e., larger Type I or smaller Type II), maternal disomy 15 (both 15s from the mother) in about 25% of cases, and the remaining subjects have either defects in the imprinting center controlling the activity of imprinted genes or due to other chromosome 15 rearrangements. PWS is characterized by a particular facial appearance, infantile hypotonia, a poor suck and feeding difficulties, hypogonadism and hypogenitalism in both sexes, short stature and small hands and feet due to growth hormone deficiency, mild learning and behavioral problems (e.g., skin picking, temper tantrums) and hyperphagia leading to early childhood obesity. Obesity is a significant health problem, if uncontrolled. PWS is considered the most common known genetic cause of morbid obesity in children. The chromosome 15q11-q13 region contains approximately 100 genes and transcripts in which about 10 are imprinted and paternally expressed. This region can be divided into four groups: 1) a proximal non-imprinted region; 2) a PWS paternal-only expressed region containing protein-coding and non-coding genes; 3) an Angelman syndrome region containing maternally expressed genes and 4) a distal non-imprinted region. This review summarizes the current understanding of the genetic causes, the natural history and clinical presentation of individuals with PWS. PMID:22043168

Scheduling Jobs and a Variable Maintenance on a Single Machine with Common Due-Date Assignment

PubMed Central

Wan, Long

2014-01-01

We investigate a common due-date assignment scheduling problem with a variable maintenance on a single machine. The goal is to minimize the total earliness, tardiness, and due-date cost. We derive some properties on an optimal solution for our problem. For a special case with identical jobs we propose an optimal polynomial time algorithm followed by a numerical example. PMID:25147861

Testing a simple control law to reduce broadband frequency harmonic vibrations using semi-active tuned mass dampers

NASA Astrophysics Data System (ADS)

Moutinho, Carlos

2015-05-01

This paper is focused on the control problems related to semi-active tuned mass dampers (TMDs) used to reduce harmonic vibrations, specially involving civil structures. A simplified version of the phase control law is derived and its effectiveness is investigated and evaluated. The objective is to improve the functioning of control systems of this type by simplifying the measurement process and reducing the number of variables involved, making the control system more feasible and reliable. Because the control law is of ON/OFF type, combined with appropriate trigger conditions, the activity of the actuation system may be significantly reduced, which may be of few seconds a day in many practical cases, increasing the durability of the device and reducing its maintenance. Moreover, due to the ability of the control system to command the motion of the inertial mass, the semi-active TMD is relatively insensitive to its initial tuning, resulting in the capability of self-tuning and in the possibility of controlling several vibration modes of a structure over a significant broadband frequency.

Distributed synchronization control of complex networks with communication constraints.

PubMed

Xu, Zhenhua; Zhang, Dan; Song, Hongbo

2016-11-01

This paper is concerned with the distributed synchronization control of complex networks with communication constraints. In this work, the controllers communicate with each other through the wireless network, acting as a controller network. Due to the constrained transmission power, techniques such as the packet size reduction and transmission rate reduction schemes are proposed which could help reduce communication load of the controller network. The packet dropout problem is also considered in the controller design since it is often encountered in networked control systems. We show that the closed-loop system can be modeled as a switched system with uncertainties and random variables. By resorting to the switched system approach and some stochastic system analysis method, a new sufficient condition is firstly proposed such that the exponential synchronization is guaranteed in the mean-square sense. The controller gains are determined by using the well-known cone complementarity linearization (CCL) algorithm. Finally, a simulation study is performed, which demonstrates the effectiveness of the proposed design algorithm. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Taenia solium cysticercosis/taeniosis: potential linkage with FAO activities; FAO support possibilities.

PubMed

Eddi, Carlos; Nari, Armando; Amanfu, William

2003-06-01

Neurocysticercosis due to Taenia solium metacestodes is an important cause of human morbidity and mortality, particularly in parts of Latin America, Africa and Asia. The disease has been recognized as potentially eradicable. Emphasis has been placed on control through mass chemotherapy of human populations to remove tapeworm carriers, but this strategy does not control the source of infections, which is cysticercosis in pigs. Also, transmission may continue due to incomplete chemotherapy coverage of human carriers or because of immigration of tapeworm carriers into controlled areas. The FAO through the Veterinary Public Health (VPH) and Food Safety program has provided support for the write-up of guidelines for cysticercosis, diagnoses and control. This should be released in a joint effort with OIE and WHO and will provide regular support to seminars, workshops and congresses related to VPH. The FAO regular program has also established a global network of people directly involved in VPH, and is currently in the process of establishing four regional networks located in Asia, Africa, Eastern and Central Europe and Latin America. The networks should provide a basic framework to spread information related to diagnosis, prevention and control of major zoonotic diseases through electronic conferences, discussions, newsletters, and a Directory to establish contact with people involved in VPH and zoonotic diseases. Through the Technical Cooperation Program (TCP) the FAO has a tool to help Member Countries to create the basic environment to control emerging zoo-sanitary problems, such as zoonotic and food borne diseases.