Stable adaptive neurocontrollers for spacecraft and space robots

NASA Technical Reports Server (NTRS)

Sanner, Robert M.

1995-01-01

This paper reviews recently developed techniques of adaptive nonlinear control using neural networks, and demonstrates their application to two important practical problems in orbital operations. An adaptive neurocontroller is first developed for spacecraft attitude control applications, and then the same design, slightly modified, is shown to be effective in the control of free-floating orbital manipulators. The algorithms discussed have guaranteed stability and convergence properties, and thus constitute viable alternatives to existing control methodologies. Simulation results are presented demonstrating the performance of each algorithm with representative dynamic models.

Design and implementation of a new modified sliding mode controller for grid-connected inverter to controlling the voltage and frequency.

PubMed

Ghanbarian, Mohammad Mehdi; Nayeripour, Majid; Rajaei, Amirhossein; Mansouri, Mohammad Mahdi

2016-03-01

As the output power of a microgrid with renewable energy sources should be regulated based on the grid conditions, using robust controllers to share and balance the power in order to regulate the voltage and frequency of microgrid is critical. Therefore a proper control system is necessary for updating the reference signals and determining the proportion of each inverter in the microgrid control. This paper proposes a new adaptive method which is robust while the conditions are changing. This controller is based on a modified sliding mode controller which provides adapting conditions in linear and nonlinear loads. The performance of the proposed method is validated by representing the simulation results and experimental lab results. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Adaptive Control Using Neural Network Augmentation for a Modified F-15 Aircraft

NASA Technical Reports Server (NTRS)

Burken, John J.; Williams-Hayes, Peggy; Karneshige, J. T.; Stachowiak, Susan J.

2006-01-01

Description of the performance of a simplified dynamic inversion controller with neural network augmentation follows. Simulation studies focus on the results with and without neural network adaptation through the use of an F-15 aircraft simulator that has been modified to include canards. Simulated control law performance with a surface failure, in addition to an aerodynamic failure, is presented. The aircraft, with adaptation, attempts to minimize the inertial cross-coupling effect of the failure (a control derivative anomaly associated with a jammed control surface). The dynamic inversion controller calculates necessary surface commands to achieve desired rates. The dynamic inversion controller uses approximate short period and roll axis dynamics. The yaw axis controller is a sideslip rate command system. Methods are described to reduce the cross-coupling effect and maintain adequate tracking errors for control surface failures. The aerodynamic failure destabilizes the pitching moment due to angle of attack. The results show that control of the aircraft with the neural networks is easier (more damped) than without the neural networks. Simulation results show neural network augmentation of the controller improves performance with aerodynamic and control surface failures in terms of tracking error and cross-coupling reduction.

Hybrid adaptive ascent flight control for a flexible launch vehicle

NASA Astrophysics Data System (ADS)

Lefevre, Brian D.

For the purpose of maintaining dynamic stability and improving guidance command tracking performance under off-nominal flight conditions, a hybrid adaptive control scheme is selected and modified for use as a launch vehicle flight controller. This architecture merges a model reference adaptive approach, which utilizes both direct and indirect adaptive elements, with a classical dynamic inversion controller. This structure is chosen for a number of reasons: the properties of the reference model can be easily adjusted to tune the desired handling qualities of the spacecraft, the indirect adaptive element (which consists of an online parameter identification algorithm) continually refines the estimates of the evolving characteristic parameters utilized in the dynamic inversion, and the direct adaptive element (which consists of a neural network) augments the linear feedback signal to compensate for any nonlinearities in the vehicle dynamics. The combination of these elements enables the control system to retain the nonlinear capabilities of an adaptive network while relying heavily on the linear portion of the feedback signal to dictate the dynamic response under most operating conditions. To begin the analysis, the ascent dynamics of a launch vehicle with a single 1st stage rocket motor (typical of the Ares 1 spacecraft) are characterized. The dynamics are then linearized with assumptions that are appropriate for a launch vehicle, so that the resulting equations may be inverted by the flight controller in order to compute the control signals necessary to generate the desired response from the vehicle. Next, the development of the hybrid adaptive launch vehicle ascent flight control architecture is discussed in detail. Alterations of the generic hybrid adaptive control architecture include the incorporation of a command conversion operation which transforms guidance input from quaternion form (as provided by NASA) to the body-fixed angular rate commands needed by the hybrid adaptive flight controller, development of a Newton's method based online parameter update that is modified to include a step size which regulates the rate of change in the parameter estimates, comparison of the modified Newton's method and recursive least squares online parameter update algorithms, modification of the neural network's input structure to accommodate for the nature of the nonlinearities present in a launch vehicle's ascent flight, examination of both tracking error based and modeling error based neural network weight update laws, and integration of feedback filters for the purpose of preventing harmful interaction between the flight control system and flexible structural modes. To validate the hybrid adaptive controller, a high-fidelity Ares I ascent flight simulator and a classical gain-scheduled proportional-integral-derivative (PID) ascent flight controller were obtained from the NASA Marshall Space Flight Center. The classical PID flight controller is used as a benchmark when analyzing the performance of the hybrid adaptive flight controller. Simulations are conducted which model both nominal and off-nominal flight conditions with structural flexibility of the vehicle either enabled or disabled. First, rigid body ascent simulations are performed with the hybrid adaptive controller under nominal flight conditions for the purpose of selecting the update laws which drive the indirect and direct adaptive components. With the neural network disabled, the results revealed that the recursive least squares online parameter update caused high frequency oscillations to appear in the engine gimbal commands. This is highly undesirable for long and slender launch vehicles, such as the Ares I, because such oscillation of the rocket nozzle could excite unstable structural flex modes. In contrast, the modified Newton's method online parameter update produced smooth control signals and was thus selected for use in the hybrid adaptive launch vehicle flight controller. In the simulations where the online parameter identification algorithm was disabled, the tracking error based neural network weight update law forced the network's output to diverge despite repeated reductions of the adaptive learning rate. As a result, the modeling error based neural network weight update law (which generated bounded signals) is utilized by the hybrid adaptive controller in all subsequent simulations. Comparing the PID and hybrid adaptive flight controllers under nominal flight conditions in rigid body ascent simulations showed that their tracking error magnitudes are similar for a period of time during the middle of the ascent phase. Though the PID controller performs better for a short interval around the 20 second mark, the hybrid adaptive controller performs far better from roughly 70 to 120 seconds. Elevating the aerodynamic loads by increasing the force and moment coefficients produced results very similar to the nominal case. However, applying a 5% or 10% thrust reduction to the first stage rocket motor causes the tracking error magnitude observed by the PID controller to be significantly elevated and diverge rapidly as the simulation concludes. In contrast, the hybrid adaptive controller steadily maintains smaller errors (often less than 50% of the corresponding PID value). Under the same sets of flight conditions with flexibility enabled, the results exhibit similar trends with the hybrid adaptive controller performing even better in each case. Again, the reduction of the first stage rocket motor's thrust clearly illustrated the superior robustness of the hybrid adaptive flight controller.

Flight Test Comparison of Different Adaptive Augmentations for Fault Tolerant Control Laws for a Modified F-15 Aircraft

NASA Technical Reports Server (NTRS)

Burken, John J.; Hanson, Curtis E.; Lee, James A.; Kaneshige, John T.

2009-01-01

This report describes the improvements and enhancements to a neural network based approach for directly adapting to aerodynamic changes resulting from damage or failures. This research is a follow-on effort to flight tests performed on the NASA F-15 aircraft as part of the Intelligent Flight Control System research effort. Previous flight test results demonstrated the potential for performance improvement under destabilizing damage conditions. Little or no improvement was provided under simulated control surface failures, however, and the adaptive system was prone to pilot-induced oscillations. An improved controller was designed to reduce the occurrence of pilot-induced oscillations and increase robustness to failures in general. This report presents an analysis of the neural networks used in the previous flight test, the improved adaptive controller, and the baseline case with no adaptation. Flight test results demonstrate significant improvement in performance by using the new adaptive controller compared with the previous adaptive system and the baseline system for control surface failures.

AFTI/F-111 MAW flight control system and redundancy management description

NASA Technical Reports Server (NTRS)

Larson, Richard R.

1987-01-01

The wing on the NASA F-111 transonic aircraft technology (TACT) airplane was modified to provide flexible leading and trailing edge flaps; this modified wing is known as the mission adaptive wing (MAW). A dual digital primary fly-by-wire flight control system was developed with analog backup reversion for redundancy. This report discusses the functions, design, and redundancy management of the flight control system for these flaps.

Visuomotor control of human adaptive locomotion: understanding the anticipatory nature.

PubMed

Higuchi, Takahiro

2013-01-01

To maintain balance during locomotion, the central nervous system (CNS) accommodates changes in the constraints of spatial environment (e.g., existence of an obstacle or changes in the surface properties). Locomotion while modifying the basic movement patterns in response to such constraints is referred to as adaptive locomotion. The most powerful means of ensuring balance during adaptive locomotion is to visually perceive the environmental properties at a distance and modify the movement patterns in an anticipatory manner to avoid perturbation altogether. For this reason, visuomotor control of adaptive locomotion is characterized, at least in part, by its anticipatory nature. The purpose of the present article is to review the relevant studies which revealed the anticipatory nature of the visuomotor control of adaptive locomotion. The anticipatory locomotor adjustments for stationary and changeable environment, as well as the spatio-temporal patterns of gaze behavior to support the anticipatory locomotor adjustments are described. Such description will clearly show that anticipatory locomotor adjustments are initiated when an object of interest (e.g., a goal or obstacle) still exists in far space. This review also show that, as a prerequisite of anticipatory locomotor adjustments, environmental properties are accurately perceived from a distance in relation to individual's action capabilities.

Highly integrated digital electronic control: Digital flight control, aircraft model identification, and adaptive engine control

NASA Technical Reports Server (NTRS)

Baer-Riedhart, Jennifer L.; Landy, Robert J.

1987-01-01

The highly integrated digital electronic control (HIDEC) program at NASA Ames Research Center, Dryden Flight Research Facility is a multiphase flight research program to quantify the benefits of promising integrated control systems. McDonnell Aircraft Company is the prime contractor, with United Technologies Pratt and Whitney Aircraft, and Lear Siegler Incorporated as major subcontractors. The NASA F-15A testbed aircraft was modified by the HIDEC program by installing a digital electronic flight control system (DEFCS) and replacing the standard F100 (Arab 3) engines with F100 engine model derivative (EMD) engines equipped with digital electronic engine controls (DEEC), and integrating the DEEC's and DEFCS. The modified aircraft provides the capability for testing many integrated control modes involving the flight controls, engine controls, and inlet controls. This paper focuses on the first two phases of the HIDEC program, which are the digital flight control system/aircraft model identification (DEFCS/AMI) phase and the adaptive engine control system (ADECS) phase.

Adaptive control of base-isolated buildings using piezoelectric friction dampers against near-field earthquakes

NASA Astrophysics Data System (ADS)

Bitaraf, Maryam; Ozbulut, Osman E.; Hurlebaus, Stefan

2010-04-01

This paper investigates the effectiveness of two adaptive control strategies for modulating control force of piezoelectric friction dampers (PFDs) that are employed as semi-active devices in combination with laminated rubber bearings for seismic protection of buildings. The first controller developed in this study is a direct adaptive fuzzy logic controller. It consists of an upper-level and a sub-level direct fuzzy controller. In the hierarchical control scheme, higher-level controller modifies universe of discourse of both premise and consequent variables of the sub-level controller using scaling factors in order to determine command voltage of the damper according to current level of ground motion. The sub-level fuzzy controller employs isolation displacement and velocity as its premise variables and command voltage as its consequent variable. The second controller is based on the simple adaptive control (SAC) method, which is a type of direct adaptive control approach. The objective of the SAC method is to make the plant, the controlled system, track the behavior of the structure with the optimum performance. By using SAC strategy, any change in the characteristics of the structure or uncertainties in the modeling of the structure and in the external excitation would be considered because it continuously monitors its own performance to modify its parameters. Here, SAC methodology is employed to obtain the required force which results in the optimum performance of the structure. Then, the command voltage of the PFD is determined to generate the desired force. For comparison purposes, an optimal controller is also developed and considered in the simulations together with maximum passive operation of the friction damper. Time-history analyses of a base-isolated five-story building are performed to evaluate the performance of the controllers. Results reveal that developed adaptive controllers can successfully improve seismic response of the base-isolated buildings against various types of earthquakes.

Adaptive Control of Non-Minimum Phase Modal Systems Using Residual Mode Filters2. Parts 1 and 2

NASA Technical Reports Server (NTRS)

Balas, Mark J.; Frost, Susan

2011-01-01

Many dynamic systems containing a large number of modes can benefit from adaptive control techniques, which are well suited to applications that have unknown parameters and poorly known operating conditions. In this paper, we focus on a direct adaptive control approach that has been extended to handle adaptive rejection of persistent disturbances. We extend this adaptive control theory to accommodate problematic modal subsystems of a plant that inhibit the adaptive controller by causing the open-loop plant to be non-minimum phase. We will modify the adaptive controller with a Residual Mode Filter (RMF) to compensate for problematic modal subsystems, thereby allowing the system to satisfy the requirements for the adaptive controller to have guaranteed convergence and bounded gains. This paper will be divided into two parts. Here in Part I we will review the basic adaptive control approach and introduce the primary ideas. In Part II, we will present the RMF methodology and complete the proofs of all our results. Also, we will apply the above theoretical results to a simple flexible structure example to illustrate the behavior with and without the residual mode filter.

Sensorimotor adaptation is influenced by background music.

PubMed

Bock, Otmar

2010-06-01

It is well established that listening to music can modify subjects' cognitive performance. The present study evaluates whether this so-called Mozart Effect extends beyond cognitive tasks and includes sensorimotor adaptation. Three subject groups listened to musical pieces that in the author's judgment were serene, neutral, or sad, respectively. This judgment was confirmed by the subjects' introspective reports. While listening to music, subjects engaged in a pointing task that required them to adapt to rotated visual feedback. All three groups adapted successfully, but the speed and magnitude of adaptive improvement was more pronounced with serene music than with the other two music types. In contrast, aftereffects upon restoration of normal feedback were independent of music type. These findings support the existence of a "Mozart effect" for strategic movement control, but not for adaptive recalibration. Possibly, listening to music modifies neural activity in an intertwined cognitive-emotional network.

Techniques for grid manipulation and adaptation. [computational fluid dynamics

NASA Technical Reports Server (NTRS)

Choo, Yung K.; Eisemann, Peter R.; Lee, Ki D.

1992-01-01

Two approaches have been taken to provide systematic grid manipulation for improved grid quality. One is the control point form (CPF) of algebraic grid generation. It provides explicit control of the physical grid shape and grid spacing through the movement of the control points. It works well in the interactive computer graphics environment and hence can be a good candidate for integration with other emerging technologies. The other approach is grid adaptation using a numerical mapping between the physical space and a parametric space. Grid adaptation is achieved by modifying the mapping functions through the effects of grid control sources. The adaptation process can be repeated in a cyclic manner if satisfactory results are not achieved after a single application.

Implementation of an Adaptive Controller System from Concept to Flight Test

NASA Technical Reports Server (NTRS)

Larson, Richard R.; Burken, John J.; Butler, Bradley S.

2009-01-01

The National Aeronautics and Space Administration Dryden Flight Research Center (Edwards, California) is conducting ongoing flight research using adaptive controller algorithms. A highly modified McDonnell-Douglas NF-15B airplane called the F-15 Intelligent Flight Control System (IFCS) was used for these algorithms. This airplane has been modified by the addition of canards and by changing the flight control systems to interface a single-string research controller processor for neural network algorithms. Research goals included demonstration of revolutionary control approaches that can efficiently optimize aircraft performance for both normal and failure conditions, and to advance neural-network-based flight control technology for new aerospace systems designs. Before the NF-15B IFCS airplane was certified for flight test, however, certain processes needed to be completed. This paper presents an overview of these processes, including a description of the initial adaptive controller concepts followed by a discussion of modeling formulation and performance testing. Upon design finalization, the next steps are: integration with the system interfaces, verification of the software, validation of the hardware to the requirements, design of failure detection, development of safety limiters to minimize the effect of erroneous neural network commands, and creation of flight test control room displays to maximize human situational awareness.

An investigation of adaptive controllers for helicopter vibration and the development of a new dual controller

NASA Technical Reports Server (NTRS)

Mookerjee, P.; Molusis, J. A.; Bar-Shalom, Y.

1985-01-01

An investigation of the properties important for the design of stochastic adaptive controllers for the higher harmonic control of helicopter vibration is presented. Three different model types are considered for the transfer relationship between the helicopter higher harmonic control input and the vibration output: (1) nonlinear; (2) linear with slow time varying coefficients; and (3) linear with constant coefficients. The stochastic controller formulations and solutions are presented for a dual, cautious, and deterministic controller for both linear and nonlinear transfer models. Extensive simulations are performed with the various models and controllers. It is shown that the cautious adaptive controller can sometimes result in unacceptable vibration control. A new second order dual controller is developed which is shown to modify the cautious adaptive controller by adding numerator and denominator correction terms to the cautious control algorithm. The new dual controller is simulated on a simple single-control vibration example and is found to achieve excellent vibration reduction and significantly improves upon the cautious controller.

Development of adaptive observation strategy using retrospective optimal interpolation

NASA Astrophysics Data System (ADS)

Noh, N.; Kim, S.; Song, H.; Lim, G.

2011-12-01

Retrospective optimal interpolation (ROI) is a method that is used to minimize cost functions with multiple minima without using adjoint models. Song and Lim (2011) perform the experiments to reduce the computational costs for implementing ROI by transforming the control variables into eigenvectors of background error covariance. We adapt the ROI algorithm to compute sensitivity estimates of severe weather events over the Korean peninsula. The eigenvectors of the ROI algorithm is modified every time the observations are assimilated. This implies that the modified eigenvectors shows the error distribution of control variables which are updated by assimilating observations. So, We can estimate the effects of the specific observations. In order to verify the adaptive observation strategy, High-impact weather over the Korean peninsula is simulated and interpreted using WRF modeling system and sensitive regions for each high-impact weather is calculated. The effects of assimilation for each observation type is discussed.

Applied adaptive disturbance rejection using output redefinition on magnetic bearings

NASA Astrophysics Data System (ADS)

Matras, Alex Logan

Recent work has shown Adaptive Disturbance Rejection to be an effective technique for rejecting forces due to imbalance, runout and base motion disturbances on flywheels supported by magnetic bearings over a large span of frequencies. Often the applicability of some of the adaptive methods is limited because they require certain properties (such as almost-strict positive realness) that magnetic bearings do not possess. In this thesis, one method for adaptive disturbance rejection, called Adaptive Feedforward Cancellation (AFC), is modified to allow for a much wider range of frequencies to be rejected. This is accomplished by redefining the output of the original system to be the output from a reduced order state estimator instead. This can give a new system with an infinite gain margin. Additionally, the adaptation laws for the two disturbance rejection gains are slightly modified so that each adapts to a different signal in order to provide the best performance. A detailed model of a magnetic bearing is developed and computer simulations based on that model are performed to give an initial test of the new control law. A state-of-the-art magnetic bearing setup is then developed and used to implement the new control laws and determine their effectiveness. The results are successful and validate the new ideas that are presented.

The Use of Statistical Process Control-Charts for Person-Fit Analysis on Computerized Adaptive Testing. LSAC Research Report Series.

ERIC Educational Resources Information Center

Meijer, Rob R.; van Krimpen-Stoop, Edith M. L. A.

In this study a cumulative-sum (CUSUM) procedure from the theory of Statistical Process Control was modified and applied in the context of person-fit analysis in a computerized adaptive testing (CAT) environment. Six person-fit statistics were proposed using the CUSUM procedure, and three of them could be used to investigate the CAT in online test…

Adaptive antenna arrays for satellite communication

NASA Technical Reports Server (NTRS)

Gupta, Inder J.

1989-01-01

The feasibility of using adaptive antenna arrays to provide interference protection in satellite communications was studied. The feedback loops as well as the sample matric inversion (SMI) algorithm for weight control were studied. Appropriate modifications in the two were made to achieve the required interference suppression. An experimental system was built to test the modified feedback loops and the modified SMI algorithm. The performance of the experimental system was evaluated using bench generated signals and signals received from TVRO geosynchronous satellites. A summary of results is given. Some suggestions for future work are also presented.

Human-Automation Interaction Design for Adaptive Cruise Control Systems of Ground Vehicles.

PubMed

Eom, Hwisoo; Lee, Sang Hun

2015-06-12

A majority of recently developed advanced vehicles have been equipped with various automated driver assistance systems, such as adaptive cruise control (ACC) and lane keeping assistance systems. ACC systems have several operational modes, and drivers can be unaware of the mode in which they are operating. Because mode confusion is a significant human error factor that contributes to traffic accidents, it is necessary to develop user interfaces for ACC systems that can reduce mode confusion. To meet this requirement, this paper presents a new human-automation interaction design methodology in which the compatibility of the machine and interface models is determined using the proposed criteria, and if the models are incompatible, one or both of the models is/are modified to make them compatible. To investigate the effectiveness of our methodology, we designed two new interfaces by separately modifying the machine model and the interface model and then performed driver-in-the-loop experiments. The results showed that modifying the machine model provides a more compact, acceptable, effective, and safe interface than modifying the interface model.

Human-Automation Interaction Design for Adaptive Cruise Control Systems of Ground Vehicles

PubMed Central

Eom, Hwisoo; Lee, Sang Hun

2015-01-01

A majority of recently developed advanced vehicles have been equipped with various automated driver assistance systems, such as adaptive cruise control (ACC) and lane keeping assistance systems. ACC systems have several operational modes, and drivers can be unaware of the mode in which they are operating. Because mode confusion is a significant human error factor that contributes to traffic accidents, it is necessary to develop user interfaces for ACC systems that can reduce mode confusion. To meet this requirement, this paper presents a new human-automation interaction design methodology in which the compatibility of the machine and interface models is determined using the proposed criteria, and if the models are incompatible, one or both of the models is/are modified to make them compatible. To investigate the effectiveness of our methodology, we designed two new interfaces by separately modifying the machine model and the interface model and then performed driver-in-the-loop experiments. The results showed that modifying the machine model provides a more compact, acceptable, effective, and safe interface than modifying the interface model. PMID:26076406

Nonlinear adaptive control system design with asymptotically stable parameter estimation error

NASA Astrophysics Data System (ADS)

Mishkov, Rumen; Darmonski, Stanislav

2018-01-01

The paper presents a new general method for nonlinear adaptive system design with asymptotic stability of the parameter estimation error. The advantages of the approach include asymptotic unknown parameter estimation without persistent excitation and capability to directly control the estimates transient response time. The method proposed modifies the basic parameter estimation dynamics designed via a known nonlinear adaptive control approach. The modification is based on the generalised prediction error, a priori constraints with a hierarchical parameter projection algorithm, and the stable data accumulation concepts. The data accumulation principle is the main tool for achieving asymptotic unknown parameter estimation. It relies on the parametric identifiability system property introduced. Necessary and sufficient conditions for exponential stability of the data accumulation dynamics are derived. The approach is applied in a nonlinear adaptive speed tracking vector control of a three-phase induction motor.

Validation of an Adaptive Combustion Instability Control Method for Gas-Turbine Engines

NASA Technical Reports Server (NTRS)

Kopasakis, George; DeLaat, John C.; Chang, Clarence T.

2004-01-01

This paper describes ongoing testing of an adaptive control method to suppress high frequency thermo-acoustic instabilities like those found in lean-burning, low emission combustors that are being developed for future aircraft gas turbine engines. The method called Adaptive Sliding Phasor Averaged Control, was previously tested in an experimental rig designed to simulate a combustor with an instability of about 530 Hz. Results published earlier, and briefly presented here, demonstrated that this method was effective in suppressing the instability. Because this test rig did not exhibit a well pronounced instability, a question remained regarding the effectiveness of the control methodology when applied to a more coherent instability. To answer this question, a modified combustor rig was assembled at the NASA Glenn Research Center in Cleveland, Ohio. The modified rig exhibited a more coherent, higher amplitude instability, but at a lower frequency of about 315 Hz. Test results show that this control method successfully reduced the instability pressure of the lower frequency test rig. In addition, due to a certain phenomena discovered and reported earlier, the so called Intra-Harmonic Coupling, a dramatic suppression of the instability was achieved by focusing control on the second harmonic of the instability. These results and their implications are discussed, as well as a hypothesis describing the mechanism of intra-harmonic coupling.

On adaptive modified projective synchronization of a supply chain management system

NASA Astrophysics Data System (ADS)

Tirandaz, Hamed

2017-12-01

In this paper, the synchronization problem of a chaotic supply chain management system is studied. A novel adaptive modified projective synchronization method is introduced to control the behaviour of the leader supply chain system by a follower chaotic system and to adjust the leader system parameters until the measurable errors of the system parameters converge to zero. The stability evaluation and convergence analysis are carried out by the Lyapanov stability theorem. The proposed synchronization and antisynchronization techniques are studied for identical supply chain chaotic systems. Finally, some numerical simulations are presented to verify the effectiveness of the theoretical discussions.

Real-Time Adaptive Control Allocation Applied to a High Performance Aircraft

NASA Technical Reports Server (NTRS)

Davidson, John B.; Lallman, Frederick J.; Bundick, W. Thomas

2001-01-01

Abstract This paper presents the development and application of one approach to the control of aircraft with large numbers of control effectors. This approach, referred to as real-time adaptive control allocation, combines a nonlinear method for control allocation with actuator failure detection and isolation. The control allocator maps moment (or angular acceleration) commands into physical control effector commands as functions of individual control effectiveness and availability. The actuator failure detection and isolation algorithm is a model-based approach that uses models of the actuators to predict actuator behavior and an adaptive decision threshold to achieve acceptable false alarm/missed detection rates. This integrated approach provides control reconfiguration when an aircraft is subjected to actuator failure, thereby improving maneuverability and survivability of the degraded aircraft. This method is demonstrated on a next generation military aircraft Lockheed-Martin Innovative Control Effector) simulation that has been modified to include a novel nonlinear fluid flow control control effector based on passive porosity. Desktop and real-time piloted simulation results demonstrate the performance of this integrated adaptive control allocation approach.

Direct Adaptive Rejection of Vortex-Induced Disturbances for a Powered SPAR Platform

NASA Technical Reports Server (NTRS)

VanZwieten, Tannen S.; Balas, Mark J.; VanZwieten, James H.; Driscoll, Frederick R.

2009-01-01

The Rapidly Deployable Stable Platform (RDSP) is a novel vessel designed to be a reconfigurable, stable at-sea platform. It consists of a detachable catamaran and spar, performing missions with the spar extending vertically below the catamaran and hoisting it completely out of the water. Multiple thrusters located along the spar allow it to be actively controlled in this configuration. A controller is presented in this work that uses an adaptive feedback algorithm in conjunction with Direct Adaptive Disturbance Rejection (DADR) to mitigate persistent, vortex-induced disturbances. Given the frequency of a disturbance, the nominal DADR scheme adaptively compensates for its unknown amplitude and phase. This algorithm is extended to adapt to a disturbance frequency that is only coarsely known by including a Phase Locked Loop (PLL). The PLL improves the frequency estimate on-line, allowing the modified controller to reduce vortex-induced motions by more than 95% using achievable thrust inputs.

Mindfulness Training Improves Problem-Focused Coping in Psychology and Medical Students: Results from a Randomized Controlled Trial

ERIC Educational Resources Information Center

Halland, E.; De Vibe, M.; Solhaug, I.; Friborg, O.; Rosenvinge, J. H.; Tyssen, R.; Sørlie, T.; Bjørndal, A.

2015-01-01

Background: Students of clinical psychology and medicine experience high levels of mental distress and low levels of life satisfaction. Using adaptive coping strategies can modify the negative effect of stressors on health. Mindfulness, it has been claimed, more adaptive coping with stress, yet few studies have investigated whether mindfulness…

Reconfigurable Control with Neural Network Augmentation for a Modified F-15 Aircraft

NASA Technical Reports Server (NTRS)

Burken, John J.; Williams-Hayes, Peggy; Kaneshige, John T.; Stachowiak, Susan J.

2006-01-01

Description of the performance of a simplified dynamic inversion controller with neural network augmentation follows. Simulation studies focus on the results with and without neural network adaptation through the use of an F-15 aircraft simulator that has been modified to include canards. Simulated control law performance with a surface failure, in addition to an aerodynamic failure, is presented. The aircraft, with adaptation, attempts to minimize the inertial cross-coupling effect of the failure (a control derivative anomaly associated with a jammed control surface). The dynamic inversion controller calculates necessary surface commands to achieve desired rates. The dynamic inversion controller uses approximate short period and roll axis dynamics. The yaw axis controller is a sideslip rate command system. Methods are described to reduce the cross-coupling effect and maintain adequate tracking errors for control surface failures. The aerodynamic failure destabilizes the pitching moment due to angle of attack. The results show that control of the aircraft with the neural networks is easier (more damped) than without the neural networks. Simulation results show neural network augmentation of the controller improves performance with aerodynamic and control surface failures in terms of tracking error and cross-coupling reduction.

Handling Qualities Evaluations of Low Complexity Model Reference Adaptive Controllers for Reduced Pitch and Roll Damping Scenarios

NASA Technical Reports Server (NTRS)

Hanson, Curt; Schaefer, Jacob; Burken, John J.; Johnson, Marcus; Nguyen, Nhan

2011-01-01

National Aeronautics and Space Administration (NASA) researchers have conducted a series of flight experiments designed to study the effects of varying levels of adaptive controller complexity on the performance and handling qualities of an aircraft under various simulated failure or damage conditions. A baseline, nonlinear dynamic inversion controller was augmented with three variations of a model reference adaptive control design. The simplest design consisted of a single adaptive parameter in each of the pitch and roll axes computed using a basic gradient-based update law. A second design was built upon the first by increasing the complexity of the update law. The third and most complex design added an additional adaptive parameter to each axis. Flight tests were conducted using NASA s Full-scale Advanced Systems Testbed, a highly modified F-18 aircraft that contains a research flight control system capable of housing advanced flight controls experiments. Each controller was evaluated against a suite of simulated failures and damage ranging from destabilization of the pitch and roll axes to significant coupling between the axes. Two pilots evaluated the three adaptive controllers as well as the non-adaptive baseline controller in a variety of dynamic maneuvers and precision flying tasks designed to uncover potential deficiencies in the handling qualities of the aircraft, and adverse interactions between the pilot and the adaptive controllers. The work was completed as part of the Integrated Resilient Aircraft Control Project under NASA s Aviation Safety Program.

Dynamic Curvature Steering Control for Autonomous Vehicle: Performance Analysis

NASA Astrophysics Data System (ADS)

Aizzat Zakaria, Muhammad; Zamzuri, Hairi; Amri Mazlan, Saiful

2016-02-01

This paper discusses the design of dynamic curvature steering control for autonomous vehicle. The lateral control and longitudinal control are discussed in this paper. The controller is designed based on the dynamic curvature calculation to estimate the path condition and modify the vehicle speed and steering wheel angle accordingly. In this paper, the simulation results are presented to show the capability of the controller to track the reference path. The controller is able to predict the path and modify the vehicle speed to suit the path condition. The effectiveness of the controller is shown in this paper whereby identical performance is achieved with the benchmark but with extra curvature adaptation capabilites.

DSP-based adaptive backstepping using the tracking errors for high-performance sensorless speed control of induction motor drive.

PubMed

Zaafouri, Abderrahmen; Regaya, Chiheb Ben; Azza, Hechmi Ben; Châari, Abdelkader

2016-01-01

This paper presents a modified structure of the backstepping nonlinear control of the induction motor (IM) fitted with an adaptive backstepping speed observer. The control design is based on the backstepping technique complemented by the introduction of integral tracking errors action to improve its robustness. Unlike other research performed on backstepping control with integral action, the control law developed in this paper does not propose the increase of the number of system state so as not increase the complexity of differential equations resolution. The digital simulation and experimental results show the effectiveness of the proposed control compared to the conventional PI control. The results analysis shows the characteristic robustness of the adaptive control to disturbances of the load, the speed variation and low speed. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

A new class of energy based control laws for revolute robot arms - Tracking control, robustness enhancement and adaptive control

NASA Technical Reports Server (NTRS)

Wen, John T.; Kreutz, Kenneth; Bayard, David S.

1988-01-01

A class of joint-level control laws for all-revolute robot arms is introduced. The analysis is similar to the recently proposed energy Liapunov function approach except that the closed-loop potential function is shaped in accordance with the underlying joint space topology. By using energy Liapunov functions with the modified potential energy, a much simpler analysis can be used to show closed-loop global asymptotic stability and local exponential stability. When Coulomb and viscous friction and model parameter errors are present, a sliding-mode-like modification of the control law is proposed to add a robustness-enhancing outer loop. Adaptive control is also addressed within the same framework. A linear-in-the-parameters formulation is adopted, and globally asymptotically stable adaptive control laws are derived by replacing the model parameters in the nonadaptive control laws by their estimates.

Effect of visuomotor-map uncertainty on visuomotor adaptation.

PubMed

Saijo, Naoki; Gomi, Hiroaki

2012-03-01

Vision and proprioception contribute to generating hand movement. If a conflict between the visual and proprioceptive feedback of hand position is given, reaching movement is disturbed initially but recovers after training. Although previous studies have predominantly investigated the adaptive change in the motor output, it is unclear whether the contributions of visual and proprioceptive feedback controls to the reaching movement are modified by visuomotor adaptation. To investigate this, we focused on the change in proprioceptive feedback control associated with visuomotor adaptation. After the adaptation to gradually introduce visuomotor rotation, the hand reached the shifted position of the visual target to move the cursor to the visual target correctly. When the cursor feedback was occasionally eliminated (probe trial), the end point of the hand movement was biased in the visual-target direction, while the movement was initiated in the adapted direction, suggesting the incomplete adaptation of proprioceptive feedback control. Moreover, after the learning of uncertain visuomotor rotation, in which the rotation angle was randomly fluctuated on a trial-by-trial basis, the end-point bias in the probe trial increased, but the initial movement direction was not affected, suggesting a reduction in the adaptation level of proprioceptive feedback control. These results suggest that the change in the relative contribution of visual and proprioceptive feedback controls to the reaching movement in response to the visuomotor-map uncertainty is involved in visuomotor adaptation, whereas feedforward control might adapt in a manner different from that of the feedback control.

A Radio-Controlled Car Challenge

ERIC Educational Resources Information Center

Roman, Harry T.

2010-01-01

Watching a radio-controlled car zip along a sidewalk or street has become a common sight. Within this toy are the basic ingredients of a mobile robot, used by industry for a variety of important and potentially dangerous tasks. In this challenge, students consider modifying an of-the-shelf, radio-controlled car, adapting it for a robotic task.

Effect of wine-based marinades on the behavior of Salmonella Typhimurium and background flora in beef fillets.

PubMed

Nisiotou, A; Chorianopoulos, N G; Gounadaki, A; Panagou, E Z; Nychas, G-J E

2013-06-17

The aim of this study was to evaluate the wine-based marinades to control the survival of acid-adapted and non-adapted Salmonella Typhimurium and background flora of fresh beef stored aerobically or under modified atmosphere. Beef slices were inoculated with a 3-strain cocktail of acid-adapted or non-adapted Salmonella Typhimurium strains DT 193, 4/74 and DSM 554 and marinated by immersion in wine (W) or wine supplemented with 0.3% thyme essential oil (WEO), for 12h at 4°C. Marinated slices were then stored under air or modified atmosphere conditions at 5°C. S. Typhimurium and background flora were followed for a 19-day period of storage. S. Typhimurium individual strains were monitored by pulsed field gel electrophoresis. Marination with wine significantly (P<0.05) reduced the background flora compared to the control (non-marinated). Furthermore, immersion of fillets in W or WEO marinades for 12h significantly (P<0.05) reduced the levels of S. Typhimurium compared to the non-marinated (control) samples by 1.1 and 1.4logCFU/g or 2.0 and 1.9logCFU/g for acid-adapted and non-adapted cells, respectively. Acid-adapted cells were more susceptible (P<0.05) to the addition of thyme essential oil in the wine marinade. The epidemic multi-drug resistant DT 193, the 4/74 and DSM 554 strains survived marination (for both W and WEO) and were detected at about similar proportions as revealed by PFGE results. Present results indicate that wine-based marinades are efficient, from a safety and shelf life stand point, in reducing pathogen's levels as well as the background beef flora. Copyright © 2013 Elsevier B.V. All rights reserved.

Adaptable Computing Environment/Self-Assembling Software

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

Osbourn, Gordon C.; Bouchard, Ann M.; Bartholomew, John W.

Complex software applications are difficult to learn to use and to remember how to use. Further, the user has no control over the functionality available in a given application. The software we use can be created and modified only by a relatively small group of elite, highly skilled artisans known as programmers. "Normal users" are powerless to create and modify software themselves, because the tools for software development, designed by and for programmers, are a barrier to entry. This software, when completed, will be a user-adaptable computing environment in which the user is really in control of his/her own software,more » able to adapt the system, make new parts of the system interactive, and even modify the behavior of the system itself. Som key features of the basic environment that have been implemented are (a) books in bookcases, where all data is stored, (b) context-sensitive compass menus (compass, because the buttons are located in compass directions relative to the mouose cursor position), (c) importing tabular data and displaying it in a book, (d) light-weight table querying/sorting, (e) a Reach&Get capability (sort of a "smart" copy/paste that prevents the user from copying invalid data), and (f) a LogBook that automatically logs all user actions that change data or the system itself. To bootstrap toward full end-user adaptability, we implemented a set of development tools. With the development tools, compass menus can be made and customized.« less

Load attenuating passively adaptive wind turbine blade

DOEpatents

Veers, Paul S.; Lobitz, Donald W.

2003-01-07

A method and apparatus for improving wind turbine performance by alleviating loads and controlling the rotor. The invention employs the use of a passively adaptive blade that senses the wind velocity or rotational speed, and accordingly modifies its aerodynamic configuration. The invention exploits the load mitigation prospects of a blade that twists toward feather as it bends. The invention includes passively adaptive wind turbine rotors or blades with currently preferred power control features. The apparatus is a composite fiber horizontal axis wind-turbine blade, in which a substantial majority of fibers in the blade skin are inclined at angles of between 15 and 30 degrees to the axis of the blade, to produces passive adaptive aeroelastic tailoring (bend-twist coupling) to alleviate loading without unduly jeopardizing performance.

Load attenuating passively adaptive wind turbine blade

DOEpatents

Veers, Paul S.; Lobitz, Donald W.

2003-01-01

A method and apparatus for improving wind turbine performance by alleviating loads and controlling the rotor. The invention employs the use of a passively adaptive blade that senses the wind velocity or rotational speed, and accordingly modifies its aerodynamic configuration. The invention exploits the load mitigation prospects of a blade that twists toward feather as it bends. The invention includes passively adaptive wind turbine rotors or blades with currently preferred power control features. The apparatus is a composite fiber horizontal axis wind-turbine blade, in which a substantial majority of fibers in the blade skin are inclined at angles of between 15 and 30 degrees to the axis of the blade, to produces passive adaptive aeroelastic tailoring (bend-twist coupling) to alleviate loading without unduly jeopardizing performance.

Development of an adaptive failure detection and identification system for detecting aircraft control element failures

NASA Technical Reports Server (NTRS)

Bundick, W. Thomas

1990-01-01

A methodology for designing a failure detection and identification (FDI) system to detect and isolate control element failures in aircraft control systems is reviewed. An FDI system design for a modified B-737 aircraft resulting from this methodology is also reviewed, and the results of evaluating this system via simulation are presented. The FDI system performed well in a no-turbulence environment, but it experienced an unacceptable number of false alarms in atmospheric turbulence. An adaptive FDI system, which adjusts thresholds and other system parameters based on the estimated turbulence level, was developed and evaluated. The adaptive system performed well over all turbulence levels simulated, reliably detecting all but the smallest magnitude partially-missing-surface failures.

Volition-adaptive control for gait training using wearable exoskeleton: preliminary tests with incomplete spinal cord injury individuals.

PubMed

Rajasekaran, Vijaykumar; López-Larraz, Eduardo; Trincado-Alonso, Fernando; Aranda, Joan; Montesano, Luis; Del-Ama, Antonio J; Pons, Jose L

2018-01-03

Gait training for individuals with neurological disorders is challenging in providing the suitable assistance and more adaptive behaviour towards user needs. The user specific adaptation can be defined based on the user interaction with the orthosis and by monitoring the user intentions. In this paper, an adaptive control model, commanded by the user intention, is evaluated using a lower limb exoskeleton with incomplete spinal cord injury individuals (SCI). A user intention based adaptive control model has been developed and evaluated with 4 incomplete SCI individuals across 3 sessions of training per individual. The adaptive control model modifies the joint impedance properties of the exoskeleton as a function of the human-orthosis interaction torques and the joint trajectory evolution along the gait sequence, in real time. The volitional input of the user is identified by monitoring the neural signals, pertaining to the user's motor activity. These volitional inputs are used as a trigger to initiate the gait movement, allowing the user to control the initialization of the exoskeleton movement, independently. A Finite-state machine based control model is used in this set-up which helps in combining the volitional orders with the gait adaptation. The exoskeleton demonstrated an adaptive assistance depending on the patients' performance without guiding them to follow an imposed trajectory. The exoskeleton initiated the trajectory based on the user intention command received from the brain machine interface, demonstrating it as a reliable trigger. The exoskeleton maintained the equilibrium by providing suitable assistance throughout the experiments. A progressive change in the maximum flexion of the knee joint was observed at the end of each session which shows improvement in the patient performance. Results of the adaptive impedance were evaluated by comparing with the application of a constant impedance value. Participants reported that the movement of the exoskeleton was flexible and the walking patterns were similar to their own distinct patterns. This study demonstrates that user specific adaptive control can be applied on a wearable robot based on the human-orthosis interaction torques and modifying the joints' impedance properties. The patients perceived no external or impulsive force and felt comfortable with the assistance provided by the exoskeleton. The main goal of such a user dependent control is to assist the patients' needs and adapt to their characteristics, thus maximizing their engagement in the therapy and avoiding slacking. In addition, the initiation directly controlled by the brain allows synchronizing the user's intention with the afferent stimulus provided by the movement of the exoskeleton, which maximizes the potentiality of the system in neuro-rehabilitative therapies.

Frontal lesions predict response to prism adaptation treatment in spatial neglect: A randomised controlled study.

PubMed

Goedert, Kelly M; Chen, Peii; Foundas, Anne L; Barrett, A M

2018-03-20

Spatial neglect commonly follows right hemisphere stroke. It is defined as impaired contralesional stimulus detection, response, or action, causing functional disability. While prism adaptation treatment is highly promising to promote functional recovery of spatial neglect, not all individuals respond. Consistent with a primary effect of prism adaptation on spatial movements, we previously demonstrated that functional improvement after prism adaptation treatment is linked to frontal lobe lesions. However, that study was a treatment-only study with no randomised control group. The current study randomised individuals with spatial neglect to receive 10 days of prism adaptation treatment or to receive only standard care (control group). Replicating our earlier results, we found that the presence of frontal lesions moderated response to prism adaptation treatment: among prism-treated patients, only those with frontal lesions demonstrated functional improvements in their neglect symptoms. Conversely, among individuals in the standard care control group, the presence of frontal lesions did not modify recovery. These results suggest that further research is needed on how frontal lesions may predict response to prism adaptation treatment. Additionally, the results help elucidate the neural network involved in spatial movement and could be used to aid decisions about treatment.

Exponentially Stabilizing Robot Control Laws

NASA Technical Reports Server (NTRS)

Wen, John T.; Bayard, David S.

1990-01-01

New class of exponentially stabilizing laws for joint-level control of robotic manipulators introduced. In case of set-point control, approach offers simplicity of proportion/derivative control architecture. In case of tracking control, approach provides several important alternatives to completed-torque method, as far as computational requirements and convergence. New control laws modified in simple fashion to obtain asymptotically stable adaptive control, when robot model and/or payload mass properties unknown.

Adaptive Arrays for Weak Interfering Signals: An Experimental System. M.S. Thesis

NASA Technical Reports Server (NTRS)

Ward, James

1987-01-01

An experimental adaptive antenna system was implemented to study the performance of adaptive arrays in the presence of weak interfering signals. It is a sidelobe canceler with two auxiliary elements. Modified feedback loops, which decorrelate the noise components of the two inputs to the loop correlators, control the array weights. Digital processing is used for algorithm implementation and performance evaluation. The results show that the system can suppress interfering signals which are 0 to 10 dB below the thermal noise level in the main channel by 20 to 30 dB. When the desired signal is strong in the auxiliary elements the amount of interference suppression decreases. The amount of degradation depends on the number of interfering signals incident on the communication system. A modified steering vector which overcomes this problem is proposed.

Progressive adaptation of a Georgian isolate of African swine fever virus to vero cells leads to a gradual attenuation of virulence in swine corresponding to major changes of the viral genome

USDA-ARS?s Scientific Manuscript database

African swine fever virus (ASFV) causes a contagious and often lethal disease of feral and domestic swine. Experimental vaccines derived from naturally occurring, genetically modified or cell culture-adapted ASFV have been evaluated but no commercial vaccine is available to control African Swine Fev...

Implementation of an Adaptive Controller System from Concept to Flight Test

NASA Technical Reports Server (NTRS)

Larson, Richard R.; Burken, John J.; Butler, Bradley S.; Yokum, Steve

2009-01-01

The National Aeronautics and Space Administration Dryden Flight Research Center (Edwards, California) is conducting ongoing flight research using adaptive controller algorithms. A highly modified McDonnell-Douglas NF-15B airplane called the F-15 Intelligent Flight Control System (IFCS) is used to test and develop these algorithms. Modifications to this airplane include adding canards and changing the flight control systems to interface a single-string research controller processor for neural network algorithms. Research goals include demonstration of revolutionary control approaches that can efficiently optimize aircraft performance in both normal and failure conditions and advancement of neural-network-based flight control technology for new aerospace system designs. This report presents an overview of the processes utilized to develop adaptive controller algorithms during a flight-test program, including a description of initial adaptive controller concepts and a discussion of modeling formulation and performance testing. Design finalization led to integration with the system interfaces, verification of the software, validation of the hardware to the requirements, design of failure detection, development of safety limiters to minimize the effect of erroneous neural network commands, and creation of flight test control room displays to maximize human situational awareness; these are also discussed.

Modified Adaptive Control for Region 3 Operation in the Presence of Wind Turbine Structural Modes

NASA Technical Reports Server (NTRS)

Frost, Susan Alane; Balas, Mark J.; Wright, Alan D.

2010-01-01

Many challenges exist for the operation of wind turbines in an efficient manner that is reliable and avoids component fatigue and failure. Turbines operate in highly turbulent environments resulting in aerodynamic loads that can easily excite turbine structural modes, possibly causing component fatigue and failure. Wind turbine manufacturers are highly motivated to reduce component fatigue and failure that can lead to loss of revenue due to turbine down time and maintenance costs. The trend in wind turbine design is toward larger, more flexible turbines that are ideally suited to adaptive control methods due to the complexity and expense required to create accurate models of their dynamic characteristics. In this paper, we design an adaptive collective pitch controller for a high-fidelity simulation of a utility-scale, variable-speed horizontal axis wind turbine operating in Region 3. The objective of the adaptive pitch controller is to regulate generator speed, accommodate wind gusts, and reduce the excitation of structural modes in the wind turbine. The control objective is accomplished by collectively pitching the turbine blades. The adaptive collective pitch controller for Region 3 was compared in simulations with a baseline classical Proportional Integrator (PI) collective pitch controller. The adaptive controller will demonstrate the ability to regulate generator speed in Region 3, while accommodating gusts, and reducing the excitation of certain structural modes in the wind turbine.

A Self Adaptive Differential Evolution Algorithm for Global Optimization

NASA Astrophysics Data System (ADS)

Kumar, Pravesh; Pant, Millie

This paper presents a new Differential Evolution algorithm based on hybridization of adaptive control parameters and trigonometric mutation. First we propose a self adaptive DE named ADE where choice of control parameter F and Cr is not fixed at some constant value but is taken iteratively. The proposed algorithm is further modified by applying trigonometric mutation in it and the corresponding algorithm is named as ATDE. The performance of ATDE is evaluated on the set of 8 benchmark functions and the results are compared with the classical DE algorithm in terms of average fitness function value, number of function evaluations, convergence time and success rate. The numerical result shows the competence of the proposed algorithm.

Wavefront control in adaptive microscopy using Shack-Hartmann sensors with arbitrarily shaped pupils.

PubMed

Dong, Bing; Booth, Martin J

2018-01-22

In adaptive optical microscopy of thick biological tissue, strong scattering and aberrations can change the effective pupil shape by rendering some Shack-Hartmann spots unusable. The change of pupil shape leads to a change of wavefront reconstruction or control matrix that should be updated accordingly. Modified slope and modal wavefront control methods based on measurements of a Shack-Hartmann wavefront sensor are proposed to accommodate an arbitrarily shaped pupil. Furthermore, we present partial wavefront control methods that remove specific aberration modes like tip, tilt and defocus from the control loop. The proposed control methods were investigated and compared by simulation using experimentally obtained aberration data. The performance was then tested experimentally through closed-loop aberration corrections using an obscured pupil.

Adaptive noise reduction circuit for a sound reproduction system

NASA Technical Reports Server (NTRS)

Engebretson, A. Maynard (Inventor); O'Connell, Michael P. (Inventor)

1995-01-01

A noise reduction circuit for a hearing aid having an adaptive filter for producing a signal which estimates the noise components present in an input signal. The circuit includes a second filter for receiving the noise-estimating signal and modifying it as a function of a user's preference or as a function of an expected noise environment. The circuit also includes a gain control for adjusting the magnitude of the modified noise-estimating signal, thereby allowing for the adjustment of the magnitude of the circuit response. The circuit also includes a signal combiner for combining the input signal with the adjusted noise-estimating signal to produce a noise reduced output signal.

Complexity and Pilot Workload Metrics for the Evaluation of Adaptive Flight Controls on a Full Scale Piloted Aircraft

NASA Technical Reports Server (NTRS)

Hanson, Curt; Schaefer, Jacob; Burken, John J.; Larson, David; Johnson, Marcus

2014-01-01

Flight research has shown the effectiveness of adaptive flight controls for improving aircraft safety and performance in the presence of uncertainties. The National Aeronautics and Space Administration's (NASA)'s Integrated Resilient Aircraft Control (IRAC) project designed and conducted a series of flight experiments to study the impact of variations in adaptive controller design complexity on performance and handling qualities. A novel complexity metric was devised to compare the degrees of simplicity achieved in three variations of a model reference adaptive controller (MRAC) for NASA's F-18 (McDonnell Douglas, now The Boeing Company, Chicago, Illinois) Full-Scale Advanced Systems Testbed (Gen-2A) aircraft. The complexity measures of these controllers are also compared to that of an earlier MRAC design for NASA's Intelligent Flight Control System (IFCS) project and flown on a highly modified F-15 aircraft (McDonnell Douglas, now The Boeing Company, Chicago, Illinois). Pilot comments during the IRAC research flights pointed to the importance of workload on handling qualities ratings for failure and damage scenarios. Modifications to existing pilot aggressiveness and duty cycle metrics are presented and applied to the IRAC controllers. Finally, while adaptive controllers may alleviate the effects of failures or damage on an aircraft's handling qualities, they also have the potential to introduce annoying changes to the flight dynamics or to the operation of aircraft systems. A nuisance rating scale is presented for the categorization of nuisance side-effects of adaptive controllers.

A modified varying-stage adaptive phase II/III clinical trial design.

PubMed

Dong, Gaohong; Vandemeulebroecke, Marc

2016-07-01

Conventionally, adaptive phase II/III clinical trials are carried out with a strict two-stage design. Recently, a varying-stage adaptive phase II/III clinical trial design has been developed. In this design, following the first stage, an intermediate stage can be adaptively added to obtain more data, so that a more informative decision can be made. Therefore, the number of further investigational stages is determined based upon data accumulated to the interim analysis. This design considers two plausible study endpoints, with one of them initially designated as the primary endpoint. Based on interim results, another endpoint can be switched as the primary endpoint. However, in many therapeutic areas, the primary study endpoint is well established. Therefore, we modify this design to consider one study endpoint only so that it may be more readily applicable in real clinical trial designs. Our simulations show that, the same as the original design, this modified design controls the Type I error rate, and the design parameters such as the threshold probability for the two-stage setting and the alpha allocation ratio in the two-stage setting versus the three-stage setting have a great impact on the design characteristics. However, this modified design requires a larger sample size for the initial stage, and the probability of futility becomes much higher when the threshold probability for the two-stage setting gets smaller. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Controls for space structures

NASA Astrophysics Data System (ADS)

Balas, Mark

1991-11-01

Assembly and operation of large space structures (LSS) in orbit will require robot-assisted docking and berthing of partially-assembled structures. These operations require new solutions to the problems of controls. This is true because of large transient and persistent disturbances, controller-structure interaction with unmodeled modes, poorly known structure parameters, slow actuator/sensor dynamical behavior, and excitation of nonlinear structure vibrations during control and assembly. For on-orbit assembly, controllers must start with finite element models of LSS and adapt on line to the best operating points, without compromising stability. This is not easy to do, since there are often unmodeled dynamic interactions between the controller and the structure. The indirect adaptive controllers are based on parameter estimation. Due to the large number of modes in LSS, this approach leads to very high-order control schemes with consequent poor stability and performance. In contrast, direct model reference adaptive controllers operate to force the LSS to track the desirable behavior of a chosen model. These schemes produce simple control algorithms which are easy to implement on line. One problem with their use for LSS has been that the model must be the same dimension as the LSS - i.e., quite large. A control theory based on the command generator tracker (CGT) ideas of Sobel, Mabins, Kaufman and Wen, Balas to obtain very low-order models based on adaptive algorithms was developed. Closed-loop stability for both finite element models and distributed parameter models of LSS was proved. In addition, successful numerical simulations on several LSS databases were obtained. An adaptive controller based on our theory was also implemented on a flexible robotic manipulator at Martin Marietta Astronautics. Computation schemes for controller-structure interaction with unmodeled modes, the residual mode filters or RMF, were developed. The RMF theory was modified to compensate slow actuator/sensor dynamics. These new ideas are being applied to LSS simulations to demonstrate the ease with which one can incorporate slow actuator/sensor effects into our design. It was also shown that residual mode filter compensation can be modified for small nonlinearities to produce exponentially stable closed-loop control.

Controls for space structures

NASA Technical Reports Server (NTRS)

Balas, Mark

1991-01-01

Assembly and operation of large space structures (LSS) in orbit will require robot-assisted docking and berthing of partially-assembled structures. These operations require new solutions to the problems of controls. This is true because of large transient and persistent disturbances, controller-structure interaction with unmodeled modes, poorly known structure parameters, slow actuator/sensor dynamical behavior, and excitation of nonlinear structure vibrations during control and assembly. For on-orbit assembly, controllers must start with finite element models of LSS and adapt on line to the best operating points, without compromising stability. This is not easy to do, since there are often unmodeled dynamic interactions between the controller and the structure. The indirect adaptive controllers are based on parameter estimation. Due to the large number of modes in LSS, this approach leads to very high-order control schemes with consequent poor stability and performance. In contrast, direct model reference adaptive controllers operate to force the LSS to track the desirable behavior of a chosen model. These schemes produce simple control algorithms which are easy to implement on line. One problem with their use for LSS has been that the model must be the same dimension as the LSS - i.e., quite large. A control theory based on the command generator tracker (CGT) ideas of Sobel, Mabins, Kaufman and Wen, Balas to obtain very low-order models based on adaptive algorithms was developed. Closed-loop stability for both finite element models and distributed parameter models of LSS was proved. In addition, successful numerical simulations on several LSS databases were obtained. An adaptive controller based on our theory was also implemented on a flexible robotic manipulator at Martin Marietta Astronautics. Computation schemes for controller-structure interaction with unmodeled modes, the residual mode filters or RMF, were developed. The RMF theory was modified to compensate slow actuator/sensor dynamics. These new ideas are being applied to LSS simulations to demonstrate the ease with which one can incorporate slow actuator/sensor effects into our design. It was also shown that residual mode filter compensation can be modified for small nonlinearities to produce exponentially stable closed-loop control. A theory for disturbance accommodating controllers based on reduced order models of structures was developed, and stability results for these controllers in closed-loop with large-scale finite element models of structures were obtained.

Algebraic and adaptive learning in neural control systems

NASA Astrophysics Data System (ADS)

Ferrari, Silvia

A systematic approach is developed for designing adaptive and reconfigurable nonlinear control systems that are applicable to plants modeled by ordinary differential equations. The nonlinear controller comprising a network of neural networks is taught using a two-phase learning procedure realized through novel techniques for initialization, on-line training, and adaptive critic design. A critical observation is that the gradients of the functions defined by the neural networks must equal corresponding linear gain matrices at chosen operating points. On-line training is based on a dual heuristic adaptive critic architecture that improves control for large, coupled motions by accounting for actual plant dynamics and nonlinear effects. An action network computes the optimal control law; a critic network predicts the derivative of the cost-to-go with respect to the state. Both networks are algebraically initialized based on prior knowledge of satisfactory pointwise linear controllers and continue to adapt on line during full-scale simulations of the plant. On-line training takes place sequentially over discrete periods of time and involves several numerical procedures. A backpropagating algorithm called Resilient Backpropagation is modified and successfully implemented to meet these objectives, without excessive computational expense. This adaptive controller is as conservative as the linear designs and as effective as a global nonlinear controller. The method is successfully implemented for the full-envelope control of a six-degree-of-freedom aircraft simulation. The results show that the on-line adaptation brings about improved performance with respect to the initialization phase during aircraft maneuvers that involve large-angle and coupled dynamics, and parameter variations.

Reinforcement Learning with Orthonormal Basis Adaptation Based on Activity-Oriented Index Allocation

NASA Astrophysics Data System (ADS)

Satoh, Hideki

An orthonormal basis adaptation method for function approximation was developed and applied to reinforcement learning with multi-dimensional continuous state space. First, a basis used for linear function approximation of a control function is set to an orthonormal basis. Next, basis elements with small activities are replaced with other candidate elements as learning progresses. As this replacement is repeated, the number of basis elements with large activities increases. Example chaos control problems for multiple logistic maps were solved, demonstrating that the method for adapting an orthonormal basis can modify a basis while holding the orthonormality in accordance with changes in the environment to improve the performance of reinforcement learning and to eliminate the adverse effects of redundant noisy states.

Marginal adaptation and retention of a glass-ionomer, resin-modified glass-ionomers and a polyacid-modified resin composite in cervical Class-V lesions.

PubMed

Gladys, S; Van Meerbeek, B; Lambrechts, P; Vanherle, G

1998-07-01

An 18-month follow-up clinical trial of one conventional glass-ionomer (HIFI Master Palette), three resin-modified glass-ionomers (Fuji II LC, Vitremer, 3M Exp. 155) and one polyacid-modified resin composite (Dyract) was conducted to evaluate their clinical effectiveness in Class-V cervical lesions. In addition, the interface between dentin and two resin-modified glass-ionomers and one polyacid-modified resin composite was examined by scanning electron microscopy (SEM). After evaluation of the restorations immediately following placement (baseline), all patients were subjected to a strict recall schedule with controls at 6, 12 and 18 months. The clinical effectiveness was recorded in terms of retention and marginal integrity, clinical microleakage, caries recurrence, and tooth vitality. A chi 2-test (p < 0.05) was used to test for significant differences between materials. In case of restoration loss or special defects, a replica was made to examine the surface texture and restoration margins by SEM. In vitro, the interface was examined by SEM after an argon-ion-beam etching technique was used to enhance surface relief and disclose interfacial substructures. Retention appeared to be good for all the materials tested. Marginal discrepancies were localized at the incisal enamel and/or the cervical dentin margin, except for the polyacid-modified resin composite that showed most of the defects at the incisal enamel margin. None of the systems could guarantee margins free of microleakage for a long time. In vitro, the type of dentin pre-treatment defines to a great extent the morphology of the resultant interface between dentin and the restorative material tested. In this clinical study, the retention rate of the tested materials was good and even excellent for some products. Perfect marginal adaptation deteriorated too fast. The marginal adaptation of the polyacid-modified resin composite at the enamel site would probably have been better by the use of selective enamel or total acid etching. Marginal sealing remains a problem. Future research should concentrate on improving the marginal adaptation and sealing capacities before a broader clinical use can be advocated.

Conceptual study of the damping of large space structures using large-stroke adaptive stiffness cables

NASA Technical Reports Server (NTRS)

Thorwald, Gregory; Mikulas, Martin M., Jr.

1992-01-01

The concept of a large-stroke adaptive stiffness cable-device for damping control of space structures with large mass is introduced. The cable is used to provide damping in several examples, and its performance is shown through numerical simulation results. Displacement and velocity information of how the structure moves is used to determine when to modify the cable's stiffness in order to provide a damping force.

An experimental adaptive array to suppress weak interfering signals

NASA Technical Reports Server (NTRS)

Walton, Eric K.; Gupta, Inder J.; Ksienski, Aharon A.; Ward, James

1988-01-01

An experimental adaptive antenna system to suppress weak interfering signals is described. It is a sidelobe canceller with two auxiliary elements. Modified feedback loops are used to control the array weights. The received signals are simulated in hardware for parameter control. Digital processing is used for algorithm implementation and performance evaluation. The experimental results are presented. They show that interfering signals as much as 10 dB below the thermal noise level in the main channel are suppressed by 20-30 dB. Such a system has potential application in suppressing the interference encountered in direct broadcast satellite communication systems.

Extraordinary Adaptive Plasticity of Colorado Potato Beetle: “Ten-Striped Spearman” in the Era of Biotechnological Warfare

PubMed Central

Cingel, Aleksandar; Savić, Jelena; Lazarević, Jelica; Ćosić, Tatjana; Raspor, Martin; Smigocki, Ann; Ninković, Slavica

2016-01-01

Expanding from remote areas of Mexico to a worldwide scale, the ten-striped insect, the Colorado potato beetle (CPB, Leptinotarsa decemlineata Say), has risen from being an innocuous beetle to a prominent global pest. A diverse life cycle, phenotypic plasticity, adaptation to adverse conditions, and capability to detoxify or tolerate toxins make this insect appear to be virtually “indestructible”. With increasing advances in molecular biology, tools of biotechnological warfare were deployed to combat CPB. In the last three decades, genetically modified potato has created a new challenge for the beetle. After reviewing hundreds of scientific papers dealing with CPB control, it became clear that even biotechnological means of control, if used alone, would not defeat the Colorado potato beetle. This control measure once again appears to be provoking the potato beetle to exhibit its remarkable adaptability. Nonetheless, the potential for adaptation to these techniques has increased our knowledge of this pest and thus opened possibilities for devising more sustainable CPB management programs. PMID:27649141

Step-control of electromechanical systems

DOEpatents

Lewis, Robert N.

1979-01-01

The response of an automatic control system to a general input signal is improved by applying a test input signal, observing the response to the test input signal and determining correctional constants necessary to provide a modified input signal to be added to the input to the system. A method is disclosed for determining correctional constants. The modified input signal, when applied in conjunction with an operating signal, provides a total system output exhibiting an improved response. This method is applicable to open-loop or closed-loop control systems. The method is also applicable to unstable systems, thus allowing controlled shut-down before dangerous or destructive response is achieved and to systems whose characteristics vary with time, thus resulting in improved adaptive systems.

Analysis of modified SMI method for adaptive array weight control

NASA Technical Reports Server (NTRS)

Dilsavor, R. L.; Moses, R. L.

1989-01-01

An adaptive array is applied to the problem of receiving a desired signal in the presence of weak interference signals which need to be suppressed. A modification, suggested by Gupta, of the sample matrix inversion (SMI) algorithm controls the array weights. In the modified SMI algorithm, interference suppression is increased by subtracting a fraction F of the noise power from the diagonal elements of the estimated covariance matrix. Given the true covariance matrix and the desired signal direction, the modified algorithm is shown to maximize a well-defined, intuitive output power ratio criterion. Expressions are derived for the expected value and variance of the array weights and output powers as a function of the fraction F and the number of snapshots used in the covariance matrix estimate. These expressions are compared with computer simulation and good agreement is found. A trade-off is found to exist between the desired level of interference suppression and the number of snapshots required in order to achieve that level with some certainty. The removal of noise eigenvectors from the covariance matrix inverse is also discussed with respect to this application. Finally, the type and severity of errors which occur in the covariance matrix estimate are characterized through simulation.

A learning flight control system for the F8-DFBW aircraft. [Digital Fly-By-Wire

NASA Technical Reports Server (NTRS)

Montgomery, R. C.; Mekel, R.; Nachmias, S.

1978-01-01

This report contains a complete description of a learning control system designed for the F8-DFBW aircraft. The system is parameter-adaptive with the additional feature that it 'learns' the variation of the control system gains needed over the flight envelope. It, thus, generates and modifies its gain schedule when suitable data are available. The report emphasizes the novel learning features of the system: the forms of representation of the flight envelope and the process by which identified parameters are used to modify the gain schedule. It contains data taken during piloted real-time 6 degree-of-freedom simulations that were used to develop and evaluate the system.

Robustness study of the pseudo open-loop controller for multiconjugate adaptive optics.

PubMed

Piatrou, Piotr; Gilles, Luc

2005-02-20

Robustness of the recently proposed "pseudo open-loop control" algorithm against various system errors has been investigated for the representative example of the Gemini-South 8-m telescope multiconjugate adaptive-optics system. The existing model to represent the adaptive-optics system with pseudo open-loop control has been modified to account for misalignments, noise and calibration errors in deformable mirrors, and wave-front sensors. Comparison with the conventional least-squares control model has been done. We show with the aid of both transfer-function pole-placement analysis and Monte Carlo simulations that POLC remains remarkably stable and robust against very large levels of system errors and outperforms in this respect least-squares control. Approximate stability margins as well as performance metrics such as Strehl ratios and rms wave-front residuals averaged over a 1-arc min field of view have been computed for different types and levels of system errors to quantify the expected performance degradation.

Inhibitory control and adaptive behaviour in children with mild intellectual disability.

PubMed

Gligorović, M; Buha Ðurović, N

2014-03-01

Inhibitory control, as one of the basic mechanisms of executive functions, is extremely important for adaptive behaviour. The relation between inhibitory control and adaptive behaviour is the most obvious in cases of behavioural disorders and psychopathology. Considering the lack of studies on this relation in children with disabilities, the aim of our research is to determine the relation between inhibitory control and adaptive behaviour in children with mild intellectual disability. The sample consists of 53 children with mild intellectual disability. Selection criteria were: IQ between 50 and 70, age between 10 and 14, absence of bilingualism, and with no medical history of neurological impairment, genetic and/or emotional problems. Modified Day-Night version of the Stroop task, and Go-no-Go Tapping task were used for the assessment of inhibitory control. Data on adaptive behaviour were obtained by applying the first part of AAMR (American Association on Mental Retardation) Adaptive Behaviour Scale-School, Second Edition (ABS-S:2). Significant relationships were determined between some aspects of inhibitory control and the most of assessed domains of adaptive behaviour. Inhibitory control measures, as a unitary inhibition model, significantly predict results on Independent Functioning, Economic Activity, Speech and Language Development, and Number and Times domains of the ABS-S:2. Inhibitory control, assessed by second part of the Stroop task, proved to be a significant factor in practical (Independent Functioning) and conceptual (Economic Activity, Speech and Language Development, and Numbers and Time) adaptive skills. The first part of the Stroop task, as a measure of selective attention, proved to be a significant factor in language and numerical demands, along with second one. Inhibitory control through motor responses proved to be a significant factor in independent functioning, economic activities, language and self-direction skills. We can conclude that inhibitory control represents a significant developmental factor of different adaptive behaviour domains in children with mild intellectual disability. © 2012 The Authors. Journal of Intellectual Disability Research © 2012 John Wiley & Sons Ltd, MENCAP & IASSIDD.

Adaptive typography for dynamic mapping environments

NASA Astrophysics Data System (ADS)

Bardon, Didier

1991-08-01

When typography moves across a map, it passes over areas of different colors, densities, and textures. In such a dynamic environment, the aspect of typography must be constantly adapted to provide disernibility for every new background. Adaptive typography undergoes two adaptive operations: background control and contrast control. The background control prevents the features of the map (edges, lines, abrupt changes of densities) from destroying the integrity of the letterform. This is achieved by smoothing the features of the map in the area where a text label is displayed. The modified area is limited to the space covered by the characters of the label. Dispositions are taken to insure that the smoothing operation does not introduce any new visual noise. The contrast control assures that there are sufficient lightness differences between the typography and its ever-changing background. For every new situation, background color and foreground color are compared and the foreground color lightness is adjusted according to a chosen contrast value. Criteria and methods of choosing the appropriate contrast value are presented as well as the experiments that led to them.

Case Study: Test Results of a Tool and Method for In-Flight, Adaptive Control System Verification on a NASA F-15 Flight Research Aircraft

NASA Technical Reports Server (NTRS)

Jacklin, Stephen A.; Schumann, Johann; Guenther, Kurt; Bosworth, John

2006-01-01

Adaptive control technologies that incorporate learning algorithms have been proposed to enable autonomous flight control and to maintain vehicle performance in the face of unknown, changing, or poorly defined operating environments [1-2]. At the present time, however, it is unknown how adaptive algorithms can be routinely verified, validated, and certified for use in safety-critical applications. Rigorous methods for adaptive software verification end validation must be developed to ensure that. the control software functions as required and is highly safe and reliable. A large gap appears to exist between the point at which control system designers feel the verification process is complete, and when FAA certification officials agree it is complete. Certification of adaptive flight control software verification is complicated by the use of learning algorithms (e.g., neural networks) and degrees of system non-determinism. Of course, analytical efforts must be made in the verification process to place guarantees on learning algorithm stability, rate of convergence, and convergence accuracy. However, to satisfy FAA certification requirements, it must be demonstrated that the adaptive flight control system is also able to fail and still allow the aircraft to be flown safely or to land, while at the same time providing a means of crew notification of the (impending) failure. It was for this purpose that the NASA Ames Confidence Tool was developed [3]. This paper presents the Confidence Tool as a means of providing in-flight software assurance monitoring of an adaptive flight control system. The paper will present the data obtained from flight testing the tool on a specially modified F-15 aircraft designed to simulate loss of flight control faces.

System For Research On Multiple-Arm Robots

NASA Technical Reports Server (NTRS)

Backes, Paul G.; Hayati, Samad; Tso, Kam S.; Hayward, Vincent

1991-01-01

Kali system of computer programs and equipment provides environment for research on distributed programming and distributed control of coordinated-multiple-arm robots. Suitable for telerobotics research involving sensing and execution of low level tasks. Software and configuration of hardware designed flexible so system modified easily to test various concepts in control and programming of robots, including multiple-arm control, redundant-arm control, shared control, traded control, force control, force/position hybrid control, design and integration of sensors, teleoperation, task-space description and control, methods of adaptive control, control of flexible arms, and human factors.

Sliding mode controller with modified sliding function for DC-DC Buck Converter.

PubMed

Naik, B B; Mehta, A J

2017-09-01

This article presents design of Sliding Mode Controller with proportional integral type sliding function for DC-DC Buck Converter for the controlled power supply. The converter with conventional sliding mode controller results in a steady state error in load voltage. The proposed modified sliding function improves the steady state and dynamic performance of the Convertor and facilitates better choices of controller tuning parameters. The conditions for existence of sliding modes for proposed control scheme are derived. The stability of the closed loop system with proposed sliding mode control is proved and improvement in steady state performance is exemplified. The idea of adaptive tuning for the proposed controller to compensate load variations is outlined. The comparative study of conventional and proposed control strategy is presented. The efficacy of the proposed strategy is endowed by the simulation and experimental results. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Reliability study of the Behavioral Assessment of the Dysexecutive Syndrome adapted for a Brazilian sample of older-adult controls and probable early Alzheimer's disease patients.

PubMed

Canali, Fabíola; Brucki, Sonia M D; Bertolucci, Paulo H F; Bueno, Orlando F A

2011-12-01

Ecological tests are useful in assessing executive function deficits and may be of value in appraising response to treatment in Alzheimer's disease patients. Our aims were to examine executive function using the Behavioral Assessment of the Dysexecutive Syndrome for a Brazilian sample of older-adult controls and probable early Alzheimer's disease patients, and verify the applicability of this test battery. Forty-one older-adult controls were matched with mild Alzheimer's disease patients by age, education, and gender. There significant inter-group differences in overall profile and almost all subtests except temporal judgment, time spent on planning the first and second Zoo Map visit, number of errors when copying drawings, naming pictures and Six Modified Elements arithmetic, and dysexecutive questionnaire self-rating. The Behavioral Assessment of the Dysexecutive Syndrome item that best discriminated controls from patients was the Modified Six Elements - adapted (general index), with a sensitivity of 80% and specificity of 90%, (AUC = 0.91, p < 0.001). Behavioral Assessment of the Dysexecutive Syndrome was effective in detecting executive function deficits in mild Alzheimer's disease patients, particularly the task switching, time monitoring, and rule-shift subtests.

Robust control of electrostatic torsional micromirrors using adaptive sliding-mode control

NASA Astrophysics Data System (ADS)

Sane, Harshad S.; Yazdi, Navid; Mastrangelo, Carlos H.

2005-01-01

This paper presents high-resolution control of torsional electrostatic micromirrors beyond their inherent pull-in instability using robust sliding-mode control (SMC). The objectives of this paper are two-fold - firstly, to demonstrate the applicability of SMC for MEMS devices; secondly - to present a modified SMC algorithm that yields improved control accuracy. SMC enables compact realization of a robust controller tolerant of device characteristic variations and nonlinearities. Robustness of the control loop is demonstrated through extensive simulations and measurements on MEMS with a wide range in their characteristics. Control of two-axis gimbaled micromirrors beyond their pull-in instability with overall 10-bit pointing accuracy is confirmed experimentally. In addition, this paper presents an analysis of the sources of errors in discrete-time implementation of the control algorithm. To minimize these errors, we present an adaptive version of the SMC algorithm that yields substantial performance improvement without considerably increasing implementation complexity.

Adaptive pitch control for variable speed wind turbines

DOEpatents

Johnson, Kathryn E [Boulder, CO; Fingersh, Lee Jay [Westminster, CO

2012-05-08

An adaptive method for adjusting blade pitch angle, and controllers implementing such a method, for achieving higher power coefficients. Average power coefficients are determined for first and second periods of operation for the wind turbine. When the average power coefficient for the second time period is larger than for the first, a pitch increment, which may be generated based on the power coefficients, is added (or the sign is retained) to the nominal pitch angle value for the wind turbine. When the average power coefficient for the second time period is less than for the first, the pitch increment is subtracted (or the sign is changed). A control signal is generated based on the adapted pitch angle value and sent to blade pitch actuators that act to change the pitch angle of the wind turbine to the new or modified pitch angle setting, and this process is iteratively performed.

An EMG-Based Control for an Upper-Limb Power-Assist Exoskeleton Robot.

PubMed

Kiguchi, K; Hayashi, Y

2012-08-01

Many kinds of power-assist robots have been developed in order to assist self-rehabilitation and/or daily life motions of physically weak persons. Several kinds of control methods have been proposed to control the power-assist robots according to user's motion intention. In this paper, an electromyogram (EMG)-based impedance control method for an upper-limb power-assist exoskeleton robot is proposed to control the robot in accordance with the user's motion intention. The proposed method is simple, easy to design, humanlike, and adaptable to any user. A neurofuzzy matrix modifier is applied to make the controller adaptable to any users. Not only the characteristics of EMG signals but also the characteristics of human body are taken into account in the proposed method. The effectiveness of the proposed method was evaluated by the experiments.

Adaptive control for accelerators

DOEpatents

Eaton, Lawrie E.; Jachim, Stephen P.; Natter, Eckard F.

1991-01-01

An adaptive feedforward control loop is provided to stabilize accelerator beam loading of the radio frequency field in an accelerator cavity during successive pulses of the beam into the cavity. A digital signal processor enables an adaptive algorithm to generate a feedforward error correcting signal functionally determined by the feedback error obtained by a beam pulse loading the cavity after the previous correcting signal was applied to the cavity. Each cavity feedforward correcting signal is successively stored in the digital processor and modified by the feedback error resulting from its application to generate the next feedforward error correcting signal. A feedforward error correcting signal is generated by the digital processor in advance of the beam pulse to enable a composite correcting signal and the beam pulse to arrive concurrently at the cavity.

Controlling chaos faster.

PubMed

Bick, Christian; Kolodziejski, Christoph; Timme, Marc

2014-09-01

Predictive feedback control is an easy-to-implement method to stabilize unknown unstable periodic orbits in chaotic dynamical systems. Predictive feedback control is severely limited because asymptotic convergence speed decreases with stronger instabilities which in turn are typical for larger target periods, rendering it harder to effectively stabilize periodic orbits of large period. Here, we study stalled chaos control, where the application of control is stalled to make use of the chaotic, uncontrolled dynamics, and introduce an adaptation paradigm to overcome this limitation and speed up convergence. This modified control scheme is not only capable of stabilizing more periodic orbits than the original predictive feedback control but also speeds up convergence for typical chaotic maps, as illustrated in both theory and application. The proposed adaptation scheme provides a way to tune parameters online, yielding a broadly applicable, fast chaos control that converges reliably, even for periodic orbits of large period.

Modified Backtracking Search Optimization Algorithm Inspired by Simulated Annealing for Constrained Engineering Optimization Problems

PubMed Central

Wang, Hailong; Sun, Yuqiu; Su, Qinghua; Xia, Xuewen

2018-01-01

The backtracking search optimization algorithm (BSA) is a population-based evolutionary algorithm for numerical optimization problems. BSA has a powerful global exploration capacity while its local exploitation capability is relatively poor. This affects the convergence speed of the algorithm. In this paper, we propose a modified BSA inspired by simulated annealing (BSAISA) to overcome the deficiency of BSA. In the BSAISA, the amplitude control factor (F) is modified based on the Metropolis criterion in simulated annealing. The redesigned F could be adaptively decreased as the number of iterations increases and it does not introduce extra parameters. A self-adaptive ε-constrained method is used to handle the strict constraints. We compared the performance of the proposed BSAISA with BSA and other well-known algorithms when solving thirteen constrained benchmarks and five engineering design problems. The simulation results demonstrated that BSAISA is more effective than BSA and more competitive with other well-known algorithms in terms of convergence speed. PMID:29666635

Adaptive Control in the Presence of Simultaneous Sensor Bias and Actuator Failures

NASA Technical Reports Server (NTRS)

Joshi, Suresh M.

2012-01-01

The problem of simultaneously accommodating unknown sensor biases and unknown actuator failures in uncertain systems is considered in a direct model reference adaptive control (MRAC) setting for state tracking using state feedback. Sensor biases and actuator faults may be present at the outset or may occur at unknown instants of time during operation. A modified MRAC law is proposed, which combines sensor bias estimation with control gain adaptation for accommodation of sensor biases and actuator failures. This control law is shown to provide signal boundedness in the resulting system. For the case when an external asymptotically stable sensor bias estimator is available, an MRAC law is developed to accomplish asymptotic state tracking and signal boundedness. For a special case wherein biases are only present in the rate measurements and bias-free position measurements are available, an MRAC law is developed using a model-independent bias estimator, and is shown to provide asymptotic state tracking with signal boundedness.

Treatment of the control mechanisms of light airplanes in the flutter clearance process

NASA Technical Reports Server (NTRS)

Breitbach, E. J.

1979-01-01

It has become more and more evident that many difficulties encountered in the course of aircraft flutter analyses can be traced to strong localized nonlinearities in the control mechanisms. To cope with these problems, more reliable mathematical models paying special attention to control system nonlinearities were established by means of modified ground vibration test procedures in combination with suitably adapted modal synthesis approaches. Three different concepts are presented.

Cluster-modified function projective synchronisation of complex networks with asymmetric coupling

NASA Astrophysics Data System (ADS)

Wang, Shuguo

2018-02-01

This paper investigates the cluster-modified function projective synchronisation (CMFPS) of a generalised linearly coupled network with asymmetric coupling and nonidentical dynamical nodes. A novel synchronisation scheme is proposed to achieve CMFPS in community networks. We use adaptive control method to derive CMFPS criteria based on Lyapunov stability theory. Each cluster of networks is synchronised with target system by state transformation with scaling function matrix. Numerical simulation results are presented finally to illustrate the effectiveness of this method.

Flight Test of an Adaptive Controller and Simulated Failure/Damage on the NASA NF-15B

NASA Technical Reports Server (NTRS)

Buschbacher, Mark; Maliska, Heather

2006-01-01

The method of flight-testing the Intelligent Flight Control System (IFCS) Second Generation (Gen-2) project on the NASA NF-15B is herein described. The Gen-2 project objective includes flight-testing a dynamic inversion controller augmented by a direct adaptive neural network to demonstrate performance improvements in the presence of simulated failure/damage. The Gen-2 objectives as implemented on the NASA NF-15B created challenges for software design, structural loading limitations, and flight test operations. Simulated failure/damage is introduced by modifying control surface commands, therefore requiring structural loads measurements. Flight-testing began with the validation of a structural loads model. Flight-testing of the Gen-2 controller continued, using test maneuvers designed in a sequenced approach. Success would clear the new controller with respect to dynamic response, simulated failure/damage, and with adaptation on and off. A handling qualities evaluation was conducted on the capability of the Gen-2 controller to restore aircraft response in the presence of a simulated failure/damage. Control room monitoring of loads sensors, flight dynamics, and controller adaptation, in addition to postflight data comparison to the simulation, ensured a safe methodology of buildup testing. Flight-testing continued without major incident to accomplish the project objectives, successfully uncovering strengths and weaknesses of the Gen-2 control approach in flight.

Investigations of respiratory control systems simulation

NASA Technical Reports Server (NTRS)

Gallagher, R. R.

1973-01-01

The Grodins' respiratory control model was investigated and it was determined that the following modifications were necessary before the model would be adaptable for current research efforts: (1) the controller equation must be modified to allow for integration of the respiratory system model with other physiological systems; (2) the system must be more closely correlated to the salient physiological functionings; (3) the respiratory frequency and the heart rate should be expanded to illustrate other physiological relationships and dependencies; and (4) the model should be adapted to particular individuals through a better defined set of initial parameter values in addition to relating these parameter values to the desired environmental conditions. Several of Milhorn's respiratory control models were also investigated in hopes of using some of their features as modifications for Grodins' model.

Adaptive antenna arrays for weak interfering signals. [in satellite communication

NASA Technical Reports Server (NTRS)

Gupta, I. J.; Ksienski, A. A.

1986-01-01

It is shown that conventional adaptive arrays are unable to suppress weak interfering signals. To overcome this problem, the feedback loops controlling the array weights were modified, reducing the noise level by reducing the correlation between the noise components of the two inputs to the loop correlator. Various techniques to decorrelate these noise components are discussed. An expression is derived for the amount of noise decorrelation required to achieve a specified interference suppression. The results are of interest in connection with satellite communications.

Flight control system development and flight test experience with the F-111 mission adaptive wing aircraft

NASA Technical Reports Server (NTRS)

Larson, R. R.

1986-01-01

The wing on the NASA F-111 transonic aircraft technology airplane was modified to provide flexible leading and trailing edge flaps. This wing is known as the mission adaptive wing (MAW) because aerodynamic efficiency can be maintained at all speeds. Unlike a conventional wing, the MAW has no spoilers, external flap hinges, or fairings to break the smooth contour. The leading edge flaps and three-segment trailing edge flaps are controlled by a redundant fly-by-wire control system that features a dual digital primary system architecture providing roll and symmetric commands to the MAW control surfaces. A segregated analog backup system is provided in the event of a primary system failure. This paper discusses the design, development, testing, qualification, and flight test experience of the MAW primary and backup flight control systems.

Adaptive Hierarchical Voltage Control of a DFIG-Based Wind Power Plant for a Grid Fault

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

Kim, Jinho; Muljadi, Eduard; Park, Jung-Wook

This paper proposes an adaptive hierarchical voltage control scheme of a doubly-fed induction generator (DFIG)-based wind power plant (WPP) that can secure more reserve of reactive power (Q) in the WPP against a grid fault. To achieve this, each DFIG controller employs an adaptive reactive power to voltage (Q-V) characteristic. The proposed adaptive Q-V characteristic is temporally modified depending on the available Q capability of a DFIG; it is dependent on the distance from a DFIG to the point of common coupling (PCC). The proposed characteristic secures more Q reserve in the WPP than the fixed one. Furthermore, it allowsmore » DFIGs to promptly inject up to the Q limit, thereby improving the PCC voltage support. To avert an overvoltage after the fault clearance, washout filters are implemented in the WPP and DFIG controllers; they can prevent a surplus Q injection after the fault clearance by eliminating the accumulated values in the proportional-integral controllers of both controllers during the fault. Test results demonstrate that the scheme can improve the voltage support capability during the fault and suppress transient overvoltage after the fault clearance under scenarios of various system and fault conditions; therefore, it helps ensure grid resilience by supporting the voltage stability.« less

Evaluation of the CATSIB DIF Procedure in a Pretest Setting

ERIC Educational Resources Information Center

Nandakumar, Ratna; Roussos, Louis

2004-01-01

A new procedure, CATSIB, for assessing differential item functioning (DIF) on computerized adaptive tests (CATs) is proposed. CATSIB, a modified SIBTEST procedure, matches test takers on estimated ability and controls for impact-induced Type 1 error inflation by employing a CAT version of the IBTEST "regression correction." The…

77 FR 13193 - Airworthiness Directives; Bombardier, Inc. Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-06

... bracket. This AD requires modifying the mounting adapters of the power control unit (PCU). We are issuing this AD to prevent loss of both rudder PCU actuators which could result in free play of the rudder... static and endurance loading conditions. The failure of the mounting brackets that attach the power...

Vascular Adaptation to Exercise in Humans: Role of Hemodynamic Stimuli

PubMed Central

Green, Daniel J.; Hopman, Maria T. E.; Padilla, Jaume; Laughlin, M. Harold; Thijssen, Dick H. J.

2017-01-01

On the 400th anniversary of Harvey's Lumleian lectures, this review focuses on “hemodynamic” forces associated with the movement of blood through arteries in humans and the functional and structural adaptations that result from repeated episodic exposure to such stimuli. The late 20th century discovery that endothelial cells modify arterial tone via paracrine transduction provoked studies exploring the direct mechanical effects of blood flow and pressure on vascular function and adaptation in vivo. In this review, we address the impact of distinct hemodynamic signals that occur in response to exercise, the interrelationships between these signals, the nature of the adaptive responses that manifest under different physiological conditions, and the implications for human health. Exercise modifies blood flow, luminal shear stress, arterial pressure, and tangential wall stress, all of which can transduce changes in arterial function, diameter, and wall thickness. There are important clinical implications of the adaptation that occurs as a consequence of repeated hemodynamic stimulation associated with exercise training in humans, including impacts on atherosclerotic risk in conduit arteries, the control of blood pressure in resistance vessels, oxygen delivery and diffusion, and microvascular health. Exercise training studies have demonstrated that direct hemodynamic impacts on the health of the artery wall contribute to the well-established decrease in cardiovascular risk attributed to physical activity. PMID:28151424

Adaptations of the vestibular system to short and long-term exposures to altered gravity

NASA Astrophysics Data System (ADS)

Bruce, L.

Long-term space flight creates unique environmental conditions to which the vestibular system must adapt for optimal survival. We are studying two aspects of this vestibular adaptation: (1) How does long-term exposure to microgravity and hypergravity affect the development of vestibular afferents? (2) How does short- term exposure to extremely rapid changes in gravity, such as those that occur during launch and landing, affect the vestibular system. During space flight the gravistatic receptors in the otolith organs are effectively unloaded. In hypergravity conditions they are overloaded. However, the angular acceleration receptors of the semicircular canals receive relatively normal stimulation in both micro- and hypergravity.Rat embryos exposed to microgravity from gestation day 10 (prior to vestibular function) until gestation day 20 (vestibular system is somewhat functional) showed that afferents from the posterior vertical canal projecting to the medial vestibular nucleus developed similarly in microgravity, hypergravity, and in controls . However, afferents from the saccule showed delayed development in microgravity as compared to development in hypergravity and in controls. Cerebellar plasticity is crucial for modification of sensory-motor control and learning. Thus we explored the possibility that strong vestibular stimuli would modify cerebellar motor control (i.e., eye movement, postural control, gut motility) by altering the morphology of cerebellar Purkinje cells. To study the effects of short-term exposures to strong vestibular stimuli we focused on structural changes in the vestibulo-cerebellum that are caused by strong vestibular stimuli. Adult mice were exposed to various combinations of constant and/or rapidly changing angular and linear accelerations for 8.5 min (the time length of shuttle launch). Our data shows that these stimuli cause intense excitation of cerebellar Purkinje cells, inducing up-regulation of clathrin-mediated endocytosis. Different types of stimulation affect Purkinje cells in particular locations of the vestibulo-cerebellum. This system allows us to study how the vestibular environment can modify cerebellar function, allowing animals to adapt to new environments. Supported by NASA grant NAG2-1353.

Autonomous Pointing Control of a Large Satellite Antenna Subject to Parametric Uncertainty

PubMed Central

Wu, Shunan; Liu, Yufei; Radice, Gianmarco; Tan, Shujun

2017-01-01

With the development of satellite mobile communications, large antennas are now widely used. The precise pointing of the antenna’s optical axis is essential for many space missions. This paper addresses the challenging problem of high-precision autonomous pointing control of a large satellite antenna. The pointing dynamics are firstly proposed. The proportional–derivative feedback and structural filter to perform pointing maneuvers and suppress antenna vibrations are then presented. An adaptive controller to estimate actual system frequencies in the presence of modal parameters uncertainty is proposed. In order to reduce periodic errors, the modified controllers, which include the proposed adaptive controller and an active disturbance rejection filter, are then developed. The system stability and robustness are analyzed and discussed in the frequency domain. Numerical results are finally provided, and the results have demonstrated that the proposed controllers have good autonomy and robustness. PMID:28287450

Adaptive sequential controller

DOEpatents

El-Sharkawi, Mohamed A.; Xing, Jian; Butler, Nicholas G.; Rodriguez, Alonso

1994-01-01

An adaptive sequential controller (50/50') for controlling a circuit breaker (52) or other switching device to substantially eliminate transients on a distribution line caused by closing and opening the circuit breaker. The device adaptively compensates for changes in the response time of the circuit breaker due to aging and environmental effects. A potential transformer (70) provides a reference signal corresponding to the zero crossing of the voltage waveform, and a phase shift comparator circuit (96) compares the reference signal to the time at which any transient was produced when the circuit breaker closed, producing a signal indicative of the adaptive adjustment that should be made. Similarly, in controlling the opening of the circuit breaker, a current transformer (88) provides a reference signal that is compared against the time at which any transient is detected when the circuit breaker last opened. An adaptive adjustment circuit (102) produces a compensation time that is appropriately modified to account for changes in the circuit breaker response, including the effect of ambient conditions and aging. When next opened or closed, the circuit breaker is activated at an appropriately compensated time, so that it closes when the voltage crosses zero and opens when the current crosses zero, minimizing any transients on the distribution line. Phase angle can be used to control the opening of the circuit breaker relative to the reference signal provided by the potential transformer.

Adaptation to Laterally Displacing Prisms in Anisometropic Amblyopia.

PubMed

Sklar, Jaime C; Goltz, Herbert C; Gane, Luke; Wong, Agnes M F

2015-06-01

Using visual feedback to modify sensorimotor output in response to changes in the external environment is essential for daily function. Prism adaptation is a well-established experimental paradigm to quantify sensorimotor adaptation; that is, how the sensorimotor system adapts to an optically-altered visuospatial environment. Amblyopia is a neurodevelopmental disorder characterized by spatiotemporal deficits in vision that impacts manual and oculomotor function. This study explored the effects of anisometropic amblyopia on prism adaptation. Eight participants with anisometropic amblyopia and 11 visually-normal adults, all right-handed, were tested. Participants pointed to visual targets and were presented with feedback of hand position near the terminus of limb movement in three blocks: baseline, adaptation, and deadaptation. Adaptation was induced by viewing with binocular 11.4° (20 prism diopter [PD]) left-shifting prisms. All tasks were performed during binocular viewing. Participants with anisometropic amblyopia required significantly more trials (i.e., increased time constant) to adapt to prismatic optical displacement than visually-normal controls. During the rapid error correction phase of adaptation, people with anisometropic amblyopia also exhibited greater variance in motor output than visually-normal controls. Amblyopia impacts on the ability to adapt the sensorimotor system to an optically-displaced visual environment. The increased time constant and greater variance in motor output during the rapid error correction phase of adaptation may indicate deficits in processing of visual information as a result of degraded spatiotemporal vision in amblyopia.

Development of the Portuguese version of the modified Japanese Orthopaedic Association Score: cross-cultural adaptation, reliability, validity and responsiveness.

PubMed

Augusto, Mateus Tomaz; Diniz, Juliete Melo; Rolemberg Dantas, Fernando Luiz; Fernandes de Oliveira, Matheus; Rotta, José Marcus; Botelho, Ricardo Vieira

2018-06-01

Spondylotic cervical myelopathy (SCM) is a common cause of spinal-related disability in the elderly. The assessment of this disability is a challenging task and depends on the subjective evaluation of the investigator. As a widespread used scale, the modified scale of the Japanese Association of Orthopedics (mJOA) should be translated and culturally adapted in the Brazilian Portuguese language (mJOA-Br) to provide its clinical and research use. This study aims to do translation, transcultural adaptation and validation of the mJOA, into Brazilian Portuguese language. Following the transcultural adaptation model described by Guillemin et al., the scale as translated into Brazilian Portuguese and back-translated to English. Afterwards, questionnaires were applied in consecutive patients with SCM and compared to a control group (without SCM). The final scale was compared to the Brazilian version of Neck Disability Index for validation. Sixty patients were submitted to the translated version of mJOA. There was strong correlation between mJOA-Br scores and NDI scores to evaluate SCM symptoms (R=-0.75). mJOA-Br was considered a valid and reliable tool to evaluate SCM patients. Copyright © 2018 Elsevier Inc. All rights reserved.

An evaluation of inferential procedures for adaptive clinical trial designs with pre-specified rules for modifying the sample size.

PubMed

Levin, Gregory P; Emerson, Sarah C; Emerson, Scott S

2014-09-01

Many papers have introduced adaptive clinical trial methods that allow modifications to the sample size based on interim estimates of treatment effect. There has been extensive commentary on type I error control and efficiency considerations, but little research on estimation after an adaptive hypothesis test. We evaluate the reliability and precision of different inferential procedures in the presence of an adaptive design with pre-specified rules for modifying the sampling plan. We extend group sequential orderings of the outcome space based on the stage at stopping, likelihood ratio statistic, and sample mean to the adaptive setting in order to compute median-unbiased point estimates, exact confidence intervals, and P-values uniformly distributed under the null hypothesis. The likelihood ratio ordering is found to average shorter confidence intervals and produce higher probabilities of P-values below important thresholds than alternative approaches. The bias adjusted mean demonstrates the lowest mean squared error among candidate point estimates. A conditional error-based approach in the literature has the benefit of being the only method that accommodates unplanned adaptations. We compare the performance of this and other methods in order to quantify the cost of failing to plan ahead in settings where adaptations could realistically be pre-specified at the design stage. We find the cost to be meaningful for all designs and treatment effects considered, and to be substantial for designs frequently proposed in the literature. © 2014, The International Biometric Society.

SMI adaptive antenna arrays for weak interfering signals. [Sample Matrix Inversion

NASA Technical Reports Server (NTRS)

Gupta, Inder J.

1986-01-01

The performance of adaptive antenna arrays in the presence of weak interfering signals (below thermal noise) is studied. It is shown that a conventional adaptive antenna array sample matrix inversion (SMI) algorithm is unable to suppress such interfering signals. To overcome this problem, the SMI algorithm is modified. In the modified algorithm, the covariance matrix is redefined such that the effect of thermal noise on the weights of adaptive arrays is reduced. Thus, the weights are dictated by relatively weak signals. It is shown that the modified algorithm provides the desired interference protection.

Cerebellar subjects show impaired adaptation of anticipatory EMG during catching.

PubMed

Lang, C E; Bastian, A J

1999-11-01

We evaluated the role of the cerebellum in adapting anticipatory muscle activity during a multijointed catching task. Individuals with and without cerebellar damage caught a series of balls of different weights dropped from above. In Experiment 1 (light-heavy-light), each subject was required to catch light balls (baseline phase), heavy balls (adaptation phase), and then light balls again (postadaptation phase). Subjects were not told when the balls would be switched, and they were required to keep their hand within a vertical spatial "window" during the catch. During the series of trials, we measured three-dimensional (3-D) position and electromyogram (EMG) from the catching arm. We modeled the adaptation process using an exponential decay function; this model allowed us to dissociate adaptation from performance variability. Results from the position data show that cerebellar subjects did not adapt or adapted very slowly to the changed ball weight when compared with the control subjects. The cerebellar group required an average of 30.9 +/- 8.7 trials (mean +/- SE) to progress approximately two-thirds of the way through the adaptation compared with 1.7 +/- 0.2 trials for the control group. Only control subjects showed a negative aftereffect indicating storage of the adaptation. No difference in performance variability existed between the two groups. EMG data show that control subjects increased their anticipatory muscle activity in the flexor muscles of the arm to control the momentum of the ball at impact. Cerebellar subjects were unable to differentially increase the anticipatory muscle activity across three joints to perform the task successfully. In Experiment 2 (heavy-light-heavy), we tested to see whether the rate of adaptation changed when adapting to a light ball versus a heavy ball. Subjects caught the heavy balls (baseline phase), the light balls (adaptation phase), and then heavy balls again (postadaptation phase). Comparison of rates of adaptation between Experiment 1 and Experiment 2 showed that the rate of adaptation was unchanged whether adapting to a light ball or a heavy ball. Given these findings, we conclude that the cerebellum is important in generating the appropriate anticipatory muscle activity across multiple muscles and modifying it in response to changing demands though trial-and-error practice.

Adaption of unstructured meshes using node movement

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

Carpenter, J.G.; McRae, V.D.S.

1996-12-31

The adaption algorithm of Benson and McRae is modified for application to unstructured grids. The weight function generation was modified for application to unstructured grids and movement was limited to prevent cross over. A NACA 0012 airfoil is used as a test case to evaluate the modified algorithm when applied to unstructured grids and compared to results obtained by Warren. An adaptive mesh solution for the Sudhoo and Hall four element airfoil is included as a demonstration case.

Disturbance-Adaptive Short-Term Frequency Support of a DFIG Associated With the Variable Gain Based on the ROCOF and Rotor Speed

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

Hwang, Min; Muljadi, Eduard; Jang, Gilsoo

This paper proposes a disturbance-adaptive short-term frequency support scheme of a doubly fed induction generator (DFIG) that can improve the frequency-supporting capability while ensuring stable operation. In the proposed scheme, the output of the additional control loop is determined as the product of the frequency deviation and adaptive gain, which is modified depending on the rate of change of frequency (ROCOF) and rotor speed. To achieve these objectives, the adaptive gain is set to be high during the early stage of a disturbance, when the ROCOF and rotor speed are high. Until the frequency nadir (FN), the gain decreases withmore » the ROCOF and rotor speed. After the FN, the gain decreases only with the rotor speed. The simulation results demonstrate that the proposed scheme improves the FN and maximum ROCOF while ensuring the stable operation of a DFIG under various wind conditions irrespective of the disturbance conditions by adaptively changing the control gain with the ROCOF and rotor speed, even if the wind speed decreases and a consecutive disturbance occurs.« less

Epidemic spreading on contact networks with adaptive weights.

PubMed

Zhu, Guanghu; Chen, Guanrong; Xu, Xin-Jian; Fu, Xinchu

2013-01-21

The heterogeneous patterns of interactions within a population are often described by contact networks, but the variety and adaptivity of contact strengths are usually ignored. This paper proposes a modified epidemic SIS model with a birth-death process and nonlinear infectivity on an adaptive and weighted contact network. The links' weights, named as 'adaptive weights', which indicate the intimacy or familiarity between two connected individuals, will reduce as the disease develops. Through mathematical and numerical analyses, conditions are established for population extermination, disease extinction and infection persistence. Particularly, it is found that the fixed weights setting can trigger the epidemic incidence, and that the adaptivity of weights cannot change the epidemic threshold but it can accelerate the disease decay and lower the endemic level. Finally, some corresponding control measures are suggested. Copyright © 2012 Elsevier Ltd. All rights reserved.

A pragmatic approach to infection prevention and control guidelines in an ambulatory care setting.

PubMed

Ng, Jessica; Le-Abuyen, Sheila; Mosley, Jane; Gardam, Michael

2014-06-01

The vast majority of infection prevention and control (IPAC) experience and practice guidance relates to the inpatient setting. We have taken a pragmatic approach to applying IPAC guidance in our ambulatory setting, and here we identify and describe the 4 key areas where we modified our IPAC program and adapted current guidelines to fit with our setting. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

A Climate Change Adaptation Strategy for Management of ...

EPA Pesticide Factsheets

Sea level rise is causing shoreline erosion, increased coastal flooding, and marsh vulnerability to the impact of storms. Coastal marshes provide flood abatement, carbon and nutrient sequestration, water quality maintenance, and habitat for fish, shellfish, and wildlife, including species of concern, such as the saltmarsh sparrow (Ammodramus caudacutus). We present a climate change adaptation strategy (CCAS) adopted by scientific, management, and policy stakeholders for managing coastal marshes and enhancing system resiliency. A common adaptive management approach previously used for restoration projects was modified to identify climate-related vulnerabilities and plan climate change adaptive actions. As an example of implementation of the CCAS, we describe the stakeholder plans and management actions the US Fish and Wildlife Service and partners developed to build coastal resiliency in the Narrow River Estuary, RI, in the aftermath of Superstorm Sandy. When possible, an experimental BACI (before-after, control-impact) design, described as pre- and post-sampling at the impact site and one or more control sites, was incorporated into the climate change adaptation and implementation plans. Specific climate change adaptive actions and monitoring plans are described and include shoreline stabilization, restoring marsh drainage, increasing marsh elevation, and enabling upland marsh migration. The CCAS provides a framework and methodology for successfully managing coa

Litter Control, Waste Management, and Recycling Resource Unit, K-6. Bulletin 1722.

ERIC Educational Resources Information Center

Louisiana State Dept. of Education, Baton Rouge.

This unit provides elementary teachers with ideas for assisting their students in developing an understanding and appreciation of sound resource use. It contains projects and activities that focus on both the litter problem and on waste management solutions. These materials can be adapted and modified to accommodate different grade levels and…

Cross-Cultural Adaptation of the Urticaria Control Test From German to Castilian Spanish.

PubMed

García-Díez, I; Curto-Barredo, L; Weller, K; Pujol, R M; Maurer, M; Giménez-Arnau, A M

2015-11-01

The clinical concept of urticaria embraces a heterogeneous group of conditions classified according to their clinical course as acute (lasting less than 6 weeks) or chronic (lasting 6 weeks or more). Chronic urticaria may be either spontaneous or induced. Few tools are available for monitoring the various clinical forms of this disease or for evaluating its impact on quality of life. The recently developed Urticaria Control Test to evaluate disease control is available in German, the original language, and American English. To culturally adapt the long and short versions of the Urticaria Control Test to Castilian Spanish to ensure equivalence between the translated items and those of the original version. To translate the Urticaria Control Test we followed the International Society for Pharmacoeconomics and Outcomes Research good practice guidelines, starting with forward translation and moving through back translation and cognitive debriefing steps. Three items were modified when the first Spanish version, translated from German, was discussed (cognitive debriefing). The revised translation was then translated back to German and sent to the Urticaria Control Test authors, who modified one item they considered had acquired a different focus through translation. A third Spanish version was then prepared and after minor proofreading changes was considered definitive. This study was the first step in making it possible to use the Urticaria Control Test questionnaire in Castilian Spanish. The next step will be to validate the translated questionnaire. Copyright © 2015 Elsevier España, S.L.U. and AEDV. All rights reserved.

Adaptive critic designs for optimal control of uncertain nonlinear systems with unmatched interconnections.

PubMed

Yang, Xiong; He, Haibo

2018-05-26

In this paper, we develop a novel optimal control strategy for a class of uncertain nonlinear systems with unmatched interconnections. To begin with, we present a stabilizing feedback controller for the interconnected nonlinear systems by modifying an array of optimal control laws of auxiliary subsystems. We also prove that this feedback controller ensures a specified cost function to achieve optimality. Then, under the framework of adaptive critic designs, we use critic networks to solve the Hamilton-Jacobi-Bellman equations associated with auxiliary subsystem optimal control laws. The critic network weights are tuned through the gradient descent method combined with an additional stabilizing term. By using the newly established weight tuning rules, we no longer need the initial admissible control condition. In addition, we demonstrate that all signals in the closed-loop auxiliary subsystems are stable in the sense of uniform ultimate boundedness by using classic Lyapunov techniques. Finally, we provide an interconnected nonlinear plant to validate the present control scheme. Copyright © 2018 Elsevier Ltd. All rights reserved.

Reconfigurable Control with Neural Network Augmentation for a Modified F-15 Aircraft

NASA Technical Reports Server (NTRS)

Burken, John J.

2007-01-01

This paper describes the performance of a simplified dynamic inversion controller with neural network supplementation. This 6 DOF (Degree-of-Freedom) simulation study focuses on the results with and without adaptation of neural networks using a simulation of the NASA modified F-15 which has canards. One area of interest is the performance of a simulated surface failure while attempting to minimize the inertial cross coupling effect of a [B] matrix failure (a control derivative anomaly associated with a jammed or missing control surface). Another area of interest and presented is simulated aerodynamic failures ([A] matrix) such as a canard failure. The controller uses explicit models to produce desired angular rate commands. The dynamic inversion calculates the necessary surface commands to achieve the desired rates. The simplified dynamic inversion uses approximate short period and roll axis dynamics. Initial results indicated that the transient response for a [B] matrix failure using a Neural Network (NN) improved the control behavior when compared to not using a neural network for a given failure, However, further evaluation of the controller was comparable, with objections io the cross coupling effects (after changes were made to the controller). This paper describes the methods employed to reduce the cross coupling effect and maintain adequate tracking errors. The IA] matrix failure results show that control of the aircraft without adaptation is more difficult [leas damped) than with active neural networks, Simulation results show Neural Network augmentation of the controller improves performance in terms of backing error and cross coupling reduction and improved performance with aerodynamic-type failures.

Optimized scheme in coal-fired boiler combustion based on information entropy and modified K-prototypes algorithm

NASA Astrophysics Data System (ADS)

Gu, Hui; Zhu, Hongxia; Cui, Yanfeng; Si, Fengqi; Xue, Rui; Xi, Han; Zhang, Jiayu

2018-06-01

An integrated combustion optimization scheme is proposed for the combined considering the restriction in coal-fired boiler combustion efficiency and outlet NOx emissions. Continuous attribute discretization and reduction techniques are handled as optimization preparation by E-Cluster and C_RED methods, in which the segmentation numbers don't need to be provided in advance and can be continuously adapted with data characters. In order to obtain results of multi-objections with clustering method for mixed data, a modified K-prototypes algorithm is then proposed. This algorithm can be divided into two stages as K-prototypes algorithm for clustering number self-adaptation and clustering for multi-objective optimization, respectively. Field tests were carried out at a 660 MW coal-fired boiler to provide real data as a case study for controllable attribute discretization and reduction in boiler system and obtaining optimization parameters considering [ maxηb, minyNOx ] multi-objective rule.

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

NASA Astrophysics Data System (ADS)

Zhai, Jianwei; Lin, Xiaoming; Zhang, Yongjun

2018-03-01

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

Integrated model reference adaptive control and time-varying angular rate estimation for micro-machined gyroscopes

NASA Astrophysics Data System (ADS)

Tsai, Nan-Chyuan; Sue, Chung-Yang

2010-02-01

Owing to the imposed but undesired accelerations such as quadrature error and cross-axis perturbation, the micro-machined gyroscope would not be unconditionally retained at resonant mode. Once the preset resonance is not sustained, the performance of the micro-gyroscope is accordingly degraded. In this article, a direct model reference adaptive control loop which is integrated with a modified disturbance estimating observer (MDEO) is proposed to guarantee the resonant oscillations at drive mode and counterbalance the undesired disturbance mainly caused by quadrature error and cross-axis perturbation. The parameters of controller are on-line innovated by the dynamic error between the MDEO output and expected response. In addition, Lyapunov stability theory is employed to examine the stability of the closed-loop control system. Finally, the efficacy of numerical evaluation on the exerted time-varying angular rate, which is to be detected and measured by the gyroscope, is verified by intensive simulations.

Training a Network of Electronic Neurons for Control of a Mobile Robot

NASA Astrophysics Data System (ADS)

Vromen, T. G. M.; Steur, E.; Nijmeijer, H.

An adaptive training procedure is developed for a network of electronic neurons, which controls a mobile robot driving around in an unknown environment while avoiding obstacles. The neuronal network controls the angular velocity of the wheels of the robot based on the sensor readings. The nodes in the neuronal network controller are clusters of neurons rather than single neurons. The adaptive training procedure ensures that the input-output behavior of the clusters is identical, even though the constituting neurons are nonidentical and have, in isolation, nonidentical responses to the same input. In particular, we let the neurons interact via a diffusive coupling, and the proposed training procedure modifies the diffusion interaction weights such that the neurons behave synchronously with a predefined response. The working principle of the training procedure is experimentally validated and results of an experiment with a mobile robot that is completely autonomously driving in an unknown environment with obstacles are presented.

The ASLOTS concept: An interactive, adaptive decision support concept for Final Approach Spacing of Aircraft (FASA). FAA-NASA Joint University Program

NASA Technical Reports Server (NTRS)

Simpson, Robert W.

1993-01-01

This presentation outlines a concept for an adaptive, interactive decision support system to assist controllers at a busy airport in achieving efficient use of multiple runways. The concept is being implemented as a computer code called FASA (Final Approach Spacing for Aircraft), and will be tested and demonstrated in ATCSIM, a high fidelity simulation of terminal area airspace and airport surface operations. Objectives are: (1) to provide automated cues to assist controllers in the sequencing and spacing of landing and takeoff aircraft; (2) to provide the controller with a limited ability to modify the sequence and spacings between aircraft, and to insert takeoffs and missed approach aircraft in the landing flows; (3) to increase spacing accuracy using more complex and precise separation criteria while reducing controller workload; and (4) achieve higher operational takeoff and landing rates on multiple runways in poor visibility.

Evolutionary online behaviour learning and adaptation in real robots.

PubMed

Silva, Fernando; Correia, Luís; Christensen, Anders Lyhne

2017-07-01

Online evolution of behavioural control on real robots is an open-ended approach to autonomous learning and adaptation: robots have the potential to automatically learn new tasks and to adapt to changes in environmental conditions, or to failures in sensors and/or actuators. However, studies have so far almost exclusively been carried out in simulation because evolution in real hardware has required several days or weeks to produce capable robots. In this article, we successfully evolve neural network-based controllers in real robotic hardware to solve two single-robot tasks and one collective robotics task. Controllers are evolved either from random solutions or from solutions pre-evolved in simulation. In all cases, capable solutions are found in a timely manner (1 h or less). Results show that more accurate simulations may lead to higher-performing controllers, and that completing the optimization process in real robots is meaningful, even if solutions found in simulation differ from solutions in reality. We furthermore demonstrate for the first time the adaptive capabilities of online evolution in real robotic hardware, including robots able to overcome faults injected in the motors of multiple units simultaneously, and to modify their behaviour in response to changes in the task requirements. We conclude by assessing the contribution of each algorithmic component on the performance of the underlying evolutionary algorithm.

On the role of model-based monitoring for adaptive planning under uncertainty

NASA Astrophysics Data System (ADS)

Raso, Luciano; Kwakkel, Jan; Timmermans, Jos; Haasnoot, Mariolijn

2016-04-01

Adaptive plans, designed to anticipate and respond to an unfolding uncertain future, have found a fertile application domain in the planning of deltas that are exposed to rapid socioeconomic development and climate change. Adaptive planning, under the moniker of adaptive delta management, is used in the Dutch Delta Program for developing a nation-wide plan to prepare for uncertain climate change and socio-economic developments. Scientifically, adaptive delta management relies heavily on Dynamic Adaptive Policy Pathways. Currently, in the Netherlands the focus is shifting towards implementing the adaptive delta plan. This shift is especially relevant because the efficacy of adaptive plans hinges on monitoring on-going developments and ensuring that actions are indeed taken if and when necessary. In the design of an effective monitoring system for an adaptive plan, three challenges have to be confronted: • Shadow of the past: The development of adaptive plans and the design of their monitoring system relies heavily on current knowledge of the system, and current beliefs about plausible future developments. A static monitoring system is therefore exposed to the exact same uncertainties one tries to address through adaptive planning. • Inhibition of learning: Recent applications of adaptive planning tend to overlook the importance of learning and new information, and fail to account for this explicitly in the design of adaptive plans. • Challenge of surprise: Adaptive policies are designed in light of the current foreseen uncertainties. However, developments that are not considered during the design phase as being plausible could still substantially affect the performance of adaptive policies. The shadow of the past, the inhibition of learning, and the challenge of surprise taken together suggest that there is a need for redesigning the concepts of monitoring and evaluation to support the implementation of adaptive plans. Innovations from control theory, triggered by the challenge of uncertainty in operational control, may offer solutions from which monitoring for adaptive planning can benefit. Specifically: (i) in control, observations are incorporated into the model through data assimilation, updating the present state, boundary conditions, and parameters based on new observations, diminishing the shadow of the past; (ii) adaptive control is a way to modify the characteristics of the internal model, incorporating new knowledge on the system, countervailing the inhibition of learning; and (iii) in closed-loop control, a continuous system update equips the controller with "inherent robustness", i.e. to capacity to adapts to new conditions even when these were not initially considered. We aim to explore how inherent robustness addresses the challenge of surprise. Innovations in model-based control might help to improve and adapt the models used to support adaptive delta management to new information (reducing uncertainty). Moreover, this would offer a starting point for using these models not only in the design of adaptive plans, but also as part of the monitoring. The proposed research requires multidisciplinary cooperation between control theory, the policy sciences, and integrated assessment modeling.

Salt adaptation in Bufo bufo

PubMed Central

Ferreira, H. G.; Jesus, C. H.

1973-01-01

1. The capacity of adaptation of toads (Bufo bufo) to environments of high salinity was studied and the relative importance of skin, kidney and urinary bladder in controlling the balance of water and salt was assessed. 2. Toads were kept in NaCl solutions of 20, 50, 110, 150 and 220 mM and studied in their fourth week of adaptation. A group of animals considered as `control' was kept in wet soil with free access to water. Plasma, ureter urine, and bladder and colon contents were analysed for sodium, potassium, chloride and osmolality, and total body sodium and water were determined. Absorption of water and 22Na through the skin, and water flow and sodium excretion through the ureter, of intact animals was studied. Hydrosmotic water transport through the isolated urinary bladder of `control' and adapted animals was determined. The effects of pitressin and aldosterone on the water and sodium balance are described. 3. The survival rates of toads kept in saline concentrations up to 150 mM were identical to that of `control' animals, but half of the animals kept in 220 mM died within 4 weeks. 4. There is a linear correlation between the sodium concentrations and osmolality of plasma and of the external media. 5. The sodium concentration in colon contents rose with rising external concentrations, up to values higher than the values in plasma. 6. Sodium concentrations and osmolalities of ureter and bladder urine increased in adapted animals, the values for bladder urine becoming much higher than those for ureter urine in animals adapted to 110, 150 and 220 mM. 7. Total body water, as a percentage of total weight was kept within very narrow limits, although the total body sodium increased with adaptation. 8. Absorption of water through the skin for the same osmotic gradients was smaller in adapted than in `control' animals. 9. The ureteral output of water of toads adapted to 110 and 150 mM-NaCl was larger than the water absorption through the skin. 10. Skin absorption of sodium was lower in animals adapted to concentrated saline solutions than in `control' animals. 11. Sodium output by the ureter was identical to skin absorption in `control' animals adapted to 20, 50 and 110 mM-NaCl but was higher in animals adapted to 150 mM-NaCl. 12. Aldosterone increased the absorption of sodium in `control' and adapted toads, but at all dose levels absorption by control was greater than by adapted animals. 13. The stimulation of water absorption by vasopressin in vivo or in isolated bladders was not modified in animals adapted to high salinities. PMID:4633911

Adaptation mechanism of interlimb coordination in human split-belt treadmill walking through learning of foot contact timing: a robotics study

PubMed Central

Fujiki, Soichiro; Aoi, Shinya; Funato, Tetsuro; Tomita, Nozomi; Senda, Kei; Tsuchiya, Kazuo

2015-01-01

Human walking behaviour adaptation strategies have previously been examined using split-belt treadmills, which have two parallel independently controlled belts. In such human split-belt treadmill walking, two types of adaptations have been identified: early and late. Early-type adaptations appear as rapid changes in interlimb and intralimb coordination activities when the belt speeds of the treadmill change between tied (same speed for both belts) and split-belt (different speeds for each belt) configurations. By contrast, late-type adaptations occur after the early-type adaptations as a gradual change and only involve interlimb coordination. Furthermore, interlimb coordination shows after-effects that are related to these adaptations. It has been suggested that these adaptations are governed primarily by the spinal cord and cerebellum, but the underlying mechanism remains unclear. Because various physiological findings suggest that foot contact timing is crucial to adaptive locomotion, this paper reports on the development of a two-layered control model for walking composed of spinal and cerebellar models, and on its use as the focus of our control model. The spinal model generates rhythmic motor commands using an oscillator network based on a central pattern generator and modulates the commands formulated in immediate response to foot contact, while the cerebellar model modifies motor commands through learning based on error information related to differences between the predicted and actual foot contact timings of each leg. We investigated adaptive behaviour and its mechanism by split-belt treadmill walking experiments using both computer simulations and an experimental bipedal robot. Our results showed that the robot exhibited rapid changes in interlimb and intralimb coordination that were similar to the early-type adaptations observed in humans. In addition, despite the lack of direct interlimb coordination control, gradual changes and after-effects in the interlimb coordination appeared in a manner that was similar to the late-type adaptations and after-effects observed in humans. The adaptation results of the robot were then evaluated in comparison with human split-belt treadmill walking, and the adaptation mechanism was clarified from a dynamic viewpoint. PMID:26289658

Adaptation mechanism of interlimb coordination in human split-belt treadmill walking through learning of foot contact timing: a robotics study.

PubMed

Fujiki, Soichiro; Aoi, Shinya; Funato, Tetsuro; Tomita, Nozomi; Senda, Kei; Tsuchiya, Kazuo

2015-09-06

Human walking behaviour adaptation strategies have previously been examined using split-belt treadmills, which have two parallel independently controlled belts. In such human split-belt treadmill walking, two types of adaptations have been identified: early and late. Early-type adaptations appear as rapid changes in interlimb and intralimb coordination activities when the belt speeds of the treadmill change between tied (same speed for both belts) and split-belt (different speeds for each belt) configurations. By contrast, late-type adaptations occur after the early-type adaptations as a gradual change and only involve interlimb coordination. Furthermore, interlimb coordination shows after-effects that are related to these adaptations. It has been suggested that these adaptations are governed primarily by the spinal cord and cerebellum, but the underlying mechanism remains unclear. Because various physiological findings suggest that foot contact timing is crucial to adaptive locomotion, this paper reports on the development of a two-layered control model for walking composed of spinal and cerebellar models, and on its use as the focus of our control model. The spinal model generates rhythmic motor commands using an oscillator network based on a central pattern generator and modulates the commands formulated in immediate response to foot contact, while the cerebellar model modifies motor commands through learning based on error information related to differences between the predicted and actual foot contact timings of each leg. We investigated adaptive behaviour and its mechanism by split-belt treadmill walking experiments using both computer simulations and an experimental bipedal robot. Our results showed that the robot exhibited rapid changes in interlimb and intralimb coordination that were similar to the early-type adaptations observed in humans. In addition, despite the lack of direct interlimb coordination control, gradual changes and after-effects in the interlimb coordination appeared in a manner that was similar to the late-type adaptations and after-effects observed in humans. The adaptation results of the robot were then evaluated in comparison with human split-belt treadmill walking, and the adaptation mechanism was clarified from a dynamic viewpoint. © 2015 The Authors.

Development of Tethered Hsp90 Inhibitors Carrying Radioiodinated Probes to Specifically Discriminate and Kill Malignant Breast Tumor Cells

DTIC Science & Technology

2016-05-01

both active (5) and inactive (12) probes. To obtain a control compound with very similar physical properties but lacking the ability to bind to Hsp90...procedure was developed and then adapted and modified to provide workable protocols for radioiodination. An inactive control molecule was also developed...955-959. 4. Impact. The successful synthesis of both and active and inactive tethered Hsp90 carrying iodine that can be successfully

Adaptive Designs for Randomized Trials in Public Health

PubMed Central

Brown, C. Hendricks; Have, Thomas R. Ten; Jo, Booil; Dagne, Getachew; Wyman, Peter A.; Muthén, Bengt; Gibbons, Robert D.

2009-01-01

In this article, we present a discussion of two general ways in which the traditional randomized trial can be modified or adapted in response to the data being collected. We use the term adaptive design to refer to a trial in which characteristics of the study itself, such as the proportion assigned to active intervention versus control, change during the trial in response to data being collected. The term adaptive sequence of trials refers to a decision-making process that fundamentally informs the conceptualization and conduct of each new trial with the results of previous trials. Our discussion below investigates the utility of these two types of adaptations for public health evaluations. Examples are provided to illustrate how adaptation can be used in practice. From these case studies, we discuss whether such evaluations can or should be analyzed as if they were formal randomized trials, and we discuss practical as well as ethical issues arising in the conduct of these new-generation trials. PMID:19296774

Machine tools and fixtures: A compilation

NASA Technical Reports Server (NTRS)

1971-01-01

As part of NASA's Technology Utilizations Program, a compilation was made of technological developments regarding machine tools, jigs, and fixtures that have been produced, modified, or adapted to meet requirements of the aerospace program. The compilation is divided into three sections that include: (1) a variety of machine tool applications that offer easier and more efficient production techniques; (2) methods, techniques, and hardware that aid in the setup, alignment, and control of machines and machine tools to further quality assurance in finished products: and (3) jigs, fixtures, and adapters that are ancillary to basic machine tools and aid in realizing their greatest potential.

Fuzzy control of burnout of multilayer ceramic actuators

NASA Astrophysics Data System (ADS)

Ling, Alice V.; Voss, David; Christodoulou, Leo

1996-08-01

To improve the yield and repeatability of the burnout process of multilayer ceramic actuators (MCAs), an intelligent processing of materials (IPM-based) control system has been developed for the manufacture of MCAs. IPM involves the active (ultimately adaptive) control of a material process using empirical or analytical models and in situ sensing of critical process states (part features and process parameters) to modify the processing conditions in real time to achieve predefined product goals. Thus, the three enabling technologies for the IPM burnout control system are process modeling, in situ sensing and intelligent control. This paper presents the design of an IPM-based control strategy for the burnout process of MCAs.

Association of Dark-Adapted Visual Function with Retinal Structural Changes in Patients with Stargardt Disease

PubMed Central

Salvatore, Serena; Fishman, Gerald A.; McAnany, J. Jason; Genead, Mohamed A.

2014-01-01

Purpose To evaluate dark-adapted retinal sensitivity in patients with Stargardt disease (STGD1) using a modified MP-1 microperimeter (MP-1S) and to compare the sensitivity loss with structural changes observed by spectral-domain optical coherence tomography (SD-OCT) and confocal scanning laser ophthalmoscope (cSLO) infrared imaging. Methods Twelve STGD1 patients and 10 normally sighted controls participated. Dark-adapted mean sensitivity (MS) was obtained using a MP-1S. Additionally, MS percent difference between the patients and the controls was obtained. Sensitivity results were superimposed on cSLO infrared images and compared with corresponding SD-OCT scans. Results Dark-adapted MS±SD was 8.34±1.54 dB for the controls and 3.68±1.74 dB for STGD1(p<0.001). There was a significant reduction in MS of 24.0% in STGD1. Sensitivity reductions were observed in areas that showed changes on cSLO infrared images and on SD-OCT, including disorganizational loss of the retinal pigment epithelium, and abnormal photoreceptor inner-segment ellipsoid (ISe) and external limiting membrane reflectance band. Conclusions With topographical accuracy, dark-adapted sensitivity measurements can be made in STGD1 and normal controls with the MP-1S. Sensitivity loss is associated with structural changes. This finding can be useful for the determination of optimal areas for potential improvement of retinal function in Stargardt patients. PMID:24280667

Approximation-based adaptive tracking control of pure-feedback nonlinear systems with multiple unknown time-varying delays.

PubMed

Wang, Min; Ge, Shuzhi Sam; Hong, Keum-Shik

2010-11-01

This paper presents adaptive neural tracking control for a class of non-affine pure-feedback systems with multiple unknown state time-varying delays. To overcome the design difficulty from non-affine structure of pure-feedback system, mean value theorem is exploited to deduce affine appearance of state variables x(i) as virtual controls α(i), and of the actual control u. The separation technique is introduced to decompose unknown functions of all time-varying delayed states into a series of continuous functions of each delayed state. The novel Lyapunov-Krasovskii functionals are employed to compensate for the unknown functions of current delayed state, which is effectively free from any restriction on unknown time-delay functions and overcomes the circular construction of controller caused by the neural approximation of a function of u and [Formula: see text] . Novel continuous functions are introduced to overcome the design difficulty deduced from the use of one adaptive parameter. To achieve uniformly ultimate boundedness of all the signals in the closed-loop system and tracking performance, control gains are effectively modified as a dynamic form with a class of even function, which makes stability analysis be carried out at the present of multiple time-varying delays. Simulation studies are provided to demonstrate the effectiveness of the proposed scheme.

Adaptive Search through Constraint Violations

DTIC Science & Technology

1990-01-01

underly counting (Gelman & Gallistel , 1978; Gelman & Meck, 1986). Modifying slightly the analysis by Gelman and Gallistel (1978), we identify three...understanding of counting, Gelman and Gallistel (1978) invented two non-standard counting tasks, ordered counting, in which the objects are counted In... Gallistel , 1978; Gelman & Meck, 1986). The most plausible explanation for this flexibility is that children can derive the control knowledge for the

Walking adaptability after a stroke and its assessment in clinical settings.

PubMed

Balasubramanian, Chitralakshmi K; Clark, David J; Fox, Emily J

2014-01-01

Control of walking has been described by a tripartite model consisting of stepping, equilibrium, and adaptability. This review focuses on walking adaptability, which is defined as the ability to modify walking to meet task goals and environmental demands. Walking adaptability is crucial to safe ambulation in the home and community environments and is often severely compromised after a stroke. Yet quantification of walking adaptability after stroke has received relatively little attention in the clinical setting. The objectives of this review were to examine the conceptual challenges for clinical measurement of walking adaptability and summarize the current state of clinical assessment for walking adaptability. We created nine domains of walking adaptability from dimensions of community mobility to address the conceptual challenges in measurement and reviewed performance-based clinical assessments of walking to determine if the assessments measure walking adaptability in these domains. Our literature review suggests the lack of a comprehensive well-tested clinical assessment tool for measuring walking adaptability. Accordingly, recommendations for the development of a comprehensive clinical assessment of walking adaptability after stroke have been presented. Such a clinical assessment will be essential for gauging recovery of walking adaptability with rehabilitation and for motivating novel strategies to enhance recovery of walking adaptability after stroke.

Walking Adaptability after a Stroke and Its Assessment in Clinical Settings

PubMed Central

Balasubramanian, Chitralakshmi K.; Clark, David J.; Fox, Emily J.

2014-01-01

Control of walking has been described by a tripartite model consisting of stepping, equilibrium, and adaptability. This review focuses on walking adaptability, which is defined as the ability to modify walking to meet task goals and environmental demands. Walking adaptability is crucial to safe ambulation in the home and community environments and is often severely compromised after a stroke. Yet quantification of walking adaptability after stroke has received relatively little attention in the clinical setting. The objectives of this review were to examine the conceptual challenges for clinical measurement of walking adaptability and summarize the current state of clinical assessment for walking adaptability. We created nine domains of walking adaptability from dimensions of community mobility to address the conceptual challenges in measurement and reviewed performance-based clinical assessments of walking to determine if the assessments measure walking adaptability in these domains. Our literature review suggests the lack of a comprehensive well-tested clinical assessment tool for measuring walking adaptability. Accordingly, recommendations for the development of a comprehensive clinical assessment of walking adaptability after stroke have been presented. Such a clinical assessment will be essential for gauging recovery of walking adaptability with rehabilitation and for motivating novel strategies to enhance recovery of walking adaptability after stroke. PMID:25254140

An application of adaptive learning to malfunction recovery

NASA Technical Reports Server (NTRS)

Cruz, R. E.

1986-01-01

A self-organizing controller is developed for a simplified two-dimensional aircraft model. The Controller learns how to pilot the aircraft through a navigational mission without exceeding pre-established position and velocity limits. The controller pilots the aircraft by activating one of eight directional actuators at all times. By continually monitoring the aircraft's position and velocity with respect to the mission, the controller progressively modifies its decision rules to improve the aircraft's performance. When the controller has learned how to pilot the aircraft, two actuators fail permanently. Despite this malfunction, the controller regains proficiency at its original task. The experimental results reported show the controller's capabilities for self-organizing control, learning, and malfunction recovery.

Retinal cell imaging in myopic chickens using adaptive optics multiphoton microscopy.

PubMed

Bueno, Juan M; Palacios, Raquel; Giakoumaki, Anastasia; Gualda, Emilio J; Schaeffel, Frank; Artal, Pablo

2014-03-01

Abnormal eye growth induced by visual deprivation can modify the structure and density of the retinal cells. We have used an adaptive optics multiphoton microscope to image photoreceptors (PRs) and ganglion cells (GCs) at different retinal locations in unstained retinas of chicken eyes with about 10D of myopia and their normal-sighted fellow eyes. In all samples, the local averaged inter-PR distance increased with eccentricity. No significant differences in PR density were found between control and myopic eyes. GC density declined in myopic eyes compared to control eyes and the inter-cell distance increased. In normal eyes, the size of the GC cell bodies increased approximately two-fold between the area centralis and the peripheral retina. In myopic eyes, this trend was preserved but the GC bodies were larger at each retinal location, compared to control eyes. Obviously, GC morphology is changing when the retinal area is enlarged in myopic eyes.

Retinal cell imaging in myopic chickens using adaptive optics multiphoton microscopy

PubMed Central

Bueno, Juan M.; Palacios, Raquel; Giakoumaki, Anastasia; Gualda, Emilio J.; Schaeffel, Frank; Artal, Pablo

2014-01-01

Abnormal eye growth induced by visual deprivation can modify the structure and density of the retinal cells. We have used an adaptive optics multiphoton microscope to image photoreceptors (PRs) and ganglion cells (GCs) at different retinal locations in unstained retinas of chicken eyes with about 10D of myopia and their normal-sighted fellow eyes. In all samples, the local averaged inter-PR distance increased with eccentricity. No significant differences in PR density were found between control and myopic eyes. GC density declined in myopic eyes compared to control eyes and the inter-cell distance increased. In normal eyes, the size of the GC cell bodies increased approximately two-fold between the area centralis and the peripheral retina. In myopic eyes, this trend was preserved but the GC bodies were larger at each retinal location, compared to control eyes. Obviously, GC morphology is changing when the retinal area is enlarged in myopic eyes. PMID:24688804

Development of model reference adaptive control theory for electric power plant control applications

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

Mabius, L.E.

1982-09-15

The scope of this effort includes the theoretical development of a multi-input, multi-output (MIMO) Model Reference Control (MRC) algorithm, (i.e., model following control law), Model Reference Adaptive Control (MRAC) algorithm and the formulation of a nonlinear model of a typical electric power plant. Previous single-input, single-output MRAC algorithm designs have been generalized to MIMO MRAC designs using the MIMO MRC algorithm. This MRC algorithm, which has been developed using Command Generator Tracker methodologies, represents the steady state behavior (in the adaptive sense) of the MRAC algorithm. The MRC algorithm is a fundamental component in the MRAC design and stability analysis.more » An enhanced MRC algorithm, which has been developed for systems with more controls than regulated outputs, alleviates the MRC stability constraint of stable plant transmission zeroes. The nonlinear power plant model is based on the Cromby model with the addition of a governor valve management algorithm, turbine dynamics and turbine interactions with extraction flows. An application of the MRC algorithm to a linearization of this model demonstrates its applicability to power plant systems. In particular, the generated power changes at 7% per minute while throttle pressure and temperature, reheat temperature and drum level are held constant with a reasonable level of control. The enhanced algorithm reduces significantly control fluctuations without modifying the output response.« less

Changes in monkey horizontal semicircular canal afferent responses after spaceflight

NASA Technical Reports Server (NTRS)

Correia, M. J.; Perachio, A. A.; Dickman, J. D.; Kozlovskaia, I. B.; Sirota, M. G.; Iakushin, S. B.; Beloozerova, I. N.

1992-01-01

Extracellular responses from single horizontal semicircular canal afferents in two rhesus monkeys were studied after recovery from a 14-day biosatellite (Cosmos 2044) orbital spaceflight. On the 1st postflight day, the mean gain for 9 different horizontal canal afferents, tested using one or several different passive yaw rotation waveforms, was nearly twice that for 20 horizontal canal afferents similarly tested during preflight and postflight control studies. Adaptation of the afferent response to passive yaw rotation on the 1st postflight day was also greater. These results suggest that at least one component of the vestibular end organ (the semicircular canals) is transiently modified after exposure to 14 days of microgravity. It is unclear whether the changes are secondary to other effects of microgravity, such as calcium loss, or an adaptive response. If the response is adaptive, then this report is the first evidence that the response of the vestibular end organ may be modified (presumably by the central nervous system via efferent connections) after prolonged unusual vestibular stimulation. If this is the case, the sites of plasticity of vestibular responses may not be exclusively within central nervous system vestibular structures, as previously believed.

Cross-cultural adaptation and validation of a Bengali version of the modified fibromyalgia impact questionnaire.

PubMed

Muquith, Mohammed A; Islam, Md Nazrul; Haq, Syed A; Ten Klooster, Peter M; Rasker, Johannes J; Yunus, Muhammad B

2012-08-27

Currently, no validated instruments are available to measure the health status of Bangladeshi patients with fibromyalgia (FM). The aims of this study were to cross-culturally adapt the modified Fibromyalgia Impact Questionnaire (FIQ) into Bengali (B-FIQ) and to test its validity and reliability in Bangladeshi patients with FM. The FIQ was translated following cross-cultural adaptation guidelines and pretested in 30 female patients with FM. Next, the adapted B-FIQ was physician-administered to 102 consecutive female FM patients together with the Health Assessment Questionnaire (HAQ), selected subscales of the SF-36, and visual analog scales for current clinical symptoms. A tender point count (TPC) was performed by an experienced rheumatologist. Forty randomly selected patients completed the B-FIQ again after 7 days. Two control groups of 50 healthy people and 50 rheumatoid arthritis (RA) patients also completed the B-FIQ. For the final B-FIQ, five physical function sub-items were replaced with culturally appropriate equivalents. Internal consistency was adequate for both the 11-item physical function subscale (α = 0.73) and the total scale (α = 0.83). With exception of the physical function subscale, expected correlations were generally observed between the B-FIQ items and selected subscales of the SF-36, HAQ, clinical symptoms, and TPC. The B-FIQ was able to discriminate between FM patients and healthy controls and between FM patients and RA patients. Test-retest reliability was adequate for the physical function subscale (r = 0.86) and individual items (r = 0.73-0.86), except anxiety (r = 0.27) and morning tiredness (r = 0.64). This study supports the reliability and validity of the B-FIQ as a measure of functional disability and health status in Bangladeshi women with FM.

Enteric neuroplasticity in seawater-adapted European eel (Anguilla anguilla).

PubMed

Sorteni, C; Clavenzani, P; De Giorgio, R; Portnoy, O; Sirri, R; Mordenti, O; Di Biase, A; Parmeggiani, A; Menconi, V; Chiocchetti, R

2014-02-01

European eels live most of their lives in freshwater until spawning migration to the Sargasso Sea. During seawater adaptation, eels modify their physiology, and their digestive system adapts to the new environment, drinking salt water to compensate for the continuous water loss. In that period, eels stop feeding until spawning. Thus, the eel represents a unique model to understand the adaptive changes of the enteric nervous system (ENS) to modified salinity and starvation. To this purpose, we assessed and compared the enteric neuronal density in the cranial portion of the intestine of freshwater eels (control), lagoon eels captured in brackish water before their migration to the Sargasso Sea (T0), and starved seawater eels hormonally induced to sexual maturity (T18; 18 weeks of starvation and treatment with standardized carp pituitary extract). Furthermore, we analyzed the modification of intestinal neuronal density of hormonally untreated eels during prolonged starvation (10 weeks) in seawater and freshwater. The density of myenteric (MP) and submucosal plexus (SMP) HuC/D-immunoreactive (Hu-IR) neurons was assessed in wholemount preparations and cryosections. The number of MP and SMP HuC/D-IR neurons progressively increased from the freshwater to the salty water habitat (control > T0 > T18; P < 0.05). Compared with freshwater eels, the number of MP and SMP HuC/D-IR neurons significantly increased (P < 0.05) in the intestine of starved untreated salt water eels. In conclusion, high salinity evokes enteric neuroplasticity as indicated by the increasing number of HuC/D-IR MP and SMP neurons, a mechanism likely contributing to maintaining the body homeostasis of this fish in extreme conditions. © 2013 Anatomical Society.

Enteric neuroplasticity in seawater-adapted European eel (Anguilla anguilla)

PubMed Central

Sorteni, C; Clavenzani, P; De Giorgio, R; Portnoy, O; Sirri, R; Mordenti, O; Di Biase, A; Parmeggiani, A; Menconi, V; Chiocchetti, R

2014-01-01

European eels live most of their lives in freshwater until spawning migration to the Sargasso Sea. During seawater adaptation, eels modify their physiology, and their digestive system adapts to the new environment, drinking salt water to compensate for the continuous water loss. In that period, eels stop feeding until spawning. Thus, the eel represents a unique model to understand the adaptive changes of the enteric nervous system (ENS) to modified salinity and starvation. To this purpose, we assessed and compared the enteric neuronal density in the cranial portion of the intestine of freshwater eels (control), lagoon eels captured in brackish water before their migration to the Sargasso Sea (T0), and starved seawater eels hormonally induced to sexual maturity (T18; 18 weeks of starvation and treatment with standardized carp pituitary extract). Furthermore, we analyzed the modification of intestinal neuronal density of hormonally untreated eels during prolonged starvation (10 weeks) in seawater and freshwater. The density of myenteric (MP) and submucosal plexus (SMP) HuC/D-immunoreactive (Hu-IR) neurons was assessed in wholemount preparations and cryosections. The number of MP and SMP HuC/D-IR neurons progressively increased from the freshwater to the salty water habitat (control > T0 > T18; P < 0.05). Compared with freshwater eels, the number of MP and SMP HuC/D-IR neurons significantly increased (P < 0.05) in the intestine of starved untreated salt water eels. In conclusion, high salinity evokes enteric neuroplasticity as indicated by the increasing number of HuC/D-IR MP and SMP neurons, a mechanism likely contributing to maintaining the body homeostasis of this fish in extreme conditions. PMID:24433383

Evolutionary online behaviour learning and adaptation in real robots

PubMed Central

Correia, Luís; Christensen, Anders Lyhne

2017-01-01

Online evolution of behavioural control on real robots is an open-ended approach to autonomous learning and adaptation: robots have the potential to automatically learn new tasks and to adapt to changes in environmental conditions, or to failures in sensors and/or actuators. However, studies have so far almost exclusively been carried out in simulation because evolution in real hardware has required several days or weeks to produce capable robots. In this article, we successfully evolve neural network-based controllers in real robotic hardware to solve two single-robot tasks and one collective robotics task. Controllers are evolved either from random solutions or from solutions pre-evolved in simulation. In all cases, capable solutions are found in a timely manner (1 h or less). Results show that more accurate simulations may lead to higher-performing controllers, and that completing the optimization process in real robots is meaningful, even if solutions found in simulation differ from solutions in reality. We furthermore demonstrate for the first time the adaptive capabilities of online evolution in real robotic hardware, including robots able to overcome faults injected in the motors of multiple units simultaneously, and to modify their behaviour in response to changes in the task requirements. We conclude by assessing the contribution of each algorithmic component on the performance of the underlying evolutionary algorithm. PMID:28791130

Study of an automatic trajectory following control system

NASA Technical Reports Server (NTRS)

Vanlandingham, H. F.; Moose, R. L.; Zwicke, P. E.; Lucas, W. H.; Brinkley, J. D.

1983-01-01

It is shown that the estimator part of the Modified Partitioned Adaptive Controller, (MPAC) developed for nonlinear aircraft dynamics of a small jet transport can adapt to sensor failures. In addition, an investigation is made into the potential usefulness of the configuration detection technique used in the MPAC and the failure detection filter is developed that determines how a noise plant output is associated with a line or plane characteristic of a failure. It is shown by computer simulation that the estimator part and the configuration detection part of the MPAC can readily adapt to actuator and sensor failures and that the failure detection filter technique cannot detect actuator or sensor failures accurately for this type of system because of the plant modeling errors. In addition, it is shown that the decision technique, developed for the failure detection filter, can accurately determine that the plant output is related to the characteristic line or plane in the presence of sensor noise.

An auto-adaptive optimization approach for targeting nonpoint source pollution control practices.

PubMed

Chen, Lei; Wei, Guoyuan; Shen, Zhenyao

2015-10-21

To solve computationally intensive and technically complex control of nonpoint source pollution, the traditional genetic algorithm was modified into an auto-adaptive pattern, and a new framework was proposed by integrating this new algorithm with a watershed model and an economic module. Although conceptually simple and comprehensive, the proposed algorithm would search automatically for those Pareto-optimality solutions without a complex calibration of optimization parameters. The model was applied in a case study in a typical watershed of the Three Gorges Reservoir area, China. The results indicated that the evolutionary process of optimization was improved due to the incorporation of auto-adaptive parameters. In addition, the proposed algorithm outperformed the state-of-the-art existing algorithms in terms of convergence ability and computational efficiency. At the same cost level, solutions with greater pollutant reductions could be identified. From a scientific viewpoint, the proposed algorithm could be extended to other watersheds to provide cost-effective configurations of BMPs.

Application of extremum seeking for time-varying systems to resonance control of RF cavities

DOE PAGES

Scheinker, Alexander

2016-09-13

A recently developed form of extremum seeking for time-varying systems is implemented in hardware for the resonance control of radio-frequency cavities without phase measurements. Normal conducting RF cavity resonance control is performed via a slug tuner, while superconducting TESLA-type cavity resonance control is performed via piezo actuators. The controller maintains resonance by minimizing reflected power by utilizing model-independent adaptive feedback. Unlike standard phase-measurement-based resonance control, the presented approach is not sensitive to arbitrary phase shifts of the RF signals due to temperature-dependent cable length or phasemeasurement hardware changes. The phase independence of this method removes common slowly varying drifts andmore » required periodic recalibration of phase-based methods. A general overview of the adaptive controller is presented along with the proof of principle experimental results at room temperature. Lastly, this method allows us to both maintain a cavity at a desired resonance frequency and also to dynamically modify its resonance frequency to track the unknown time-varying frequency of an RF source, thereby maintaining maximal cavity field strength, based only on power-level measurements.« less

Comparison between different sets of suspension parameters and introduction of new modified skyhook control strategy incorporating varying road condition

NASA Astrophysics Data System (ADS)

Abul Kashem, Saad Bin; Ektesabi, Mehran; Nagarajah, Romesh

2012-07-01

This study examines the uncertainties in modelling a quarter car suspension system caused by the effect of different sets of suspension parameters of a corresponding mathematical model. To overcome this problem, 11 sets of identified parameters of a suspension system have been compared, taken from the most recent published work. From this investigation, a set of parameters were chosen which showed a better performance than others in respect of peak amplitude and settling time. These chosen parameters were then used to investigate the performance of a new modified continuous skyhook control strategy with adaptive gain that dictates the vehicle's semi-active suspension system. The proposed system first captures the road profile input over a certain period. Then it calculates the best possible value of the skyhook gain (SG) for the subsequent process. Meanwhile the system is controlled according to the new modified skyhook control law using an initial or previous value of the SG. In this study, the proposed suspension system is compared with passive and other recently reported skyhook controlled semi-active suspension systems. Its performances have been evaluated in terms of ride comfort and road handling performance. The model has been validated in accordance with the international standards of admissible acceleration levels ISO2631 and human vibration perception.

Analysis and Characterization of 3-(3,4-Dichlorophenyl)-1,1-Dimethylurea (DCMU)-resistant Euglena

PubMed Central

Calvayrac, Régis; Bomsel, Jean-Loup; Laval-Martin, Danielle

1979-01-01

Cultures of Euglena gracilis Klebs strain Z Pringsheim were grown photoorganotrophically in the presence of different concentrations of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) in the range of 0.05 to 250 micromolar. Cultures were serially transferred and various metabolic parameters were followed for 10 weeks. A process of adaptation occurred which was divided operationally into three phases. A phase of ultrastructural disorganization occurred, succeeded by a recovery phase; their intensity and duration were functions of the dose of DCMU. A stable adaptation phase then ensued. This phase was observed in all cultures except that exposed to the highest DCMU concentration. Adapted cells from all of the DCMU cultures contained twice the protein and half the paramylon of the control cells and thus utilized the carbon source to accumulate cellular reserves with only half the efficiency of controls. DCMU affected cellular metabolism as well as photosynthesis. The energy charge remained at high levels throughout adaptation, although the size of the adenylate pool was half that of controls at the disorganized phase. At this stage the ultrastructure of chloroplasts and mitochondria was considerably modified. The progressive changes of the parameters studied appeared to affect all of the cells in a given culture. Images PMID:16660827

Adaptive optics vision simulation and perceptual learning system based on a 35-element bimorph deformable mirror.

PubMed

Dai, Yun; Zhao, Lina; Xiao, Fei; Zhao, Haoxin; Bao, Hua; Zhou, Hong; Zhou, Yifeng; Zhang, Yudong

2015-02-10

An adaptive optics visual simulation combined with a perceptual learning (PL) system based on a 35-element bimorph deformable mirror (DM) was established. The larger stroke and smaller size of the bimorph DM made the system have larger aberration correction or superposition ability and be more compact. By simply modifying the control matrix or the reference matrix, select correction or superposition of aberrations was realized in real time similar to a conventional adaptive optics closed-loop correction. PL function was first integrated in addition to conventional adaptive optics visual simulation. PL training undertaken with high-order aberrations correction obviously improved the visual function of adult anisometropic amblyopia. The preliminary application of high-order aberrations correction with PL training on amblyopia treatment was being validated with a large scale population, which might have great potential in amblyopia treatment and visual performance maintenance.

An adaptive deep-coupled GNSS/INS navigation system with hybrid pre-filter processing

NASA Astrophysics Data System (ADS)

Wu, Mouyan; Ding, Jicheng; Zhao, Lin; Kang, Yingyao; Luo, Zhibin

2018-02-01

The deep-coupling of a global navigation satellite system (GNSS) with an inertial navigation system (INS) can provide accurate and reliable navigation information. There are several kinds of deeply-coupled structures. These can be divided mainly into coherent and non-coherent pre-filter based structures, which have their own strong advantages and disadvantages, especially in accuracy and robustness. In this paper, the existing pre-filters of the deeply-coupled structures are analyzed and modified to improve them firstly. Then, an adaptive GNSS/INS deeply-coupled algorithm with hybrid pre-filters processing is proposed to combine the advantages of coherent and non-coherent structures. An adaptive hysteresis controller is designed to implement the hybrid pre-filters processing strategy. The simulation and vehicle test results show that the adaptive deeply-coupled algorithm with hybrid pre-filters processing can effectively improve navigation accuracy and robustness, especially in a GNSS-challenged environment.

Magnetic induction of hyperthermia by a modified self-learning fuzzy temperature controller

NASA Astrophysics Data System (ADS)

Wang, Wei-Cheng; Tai, Cheng-Chi

2017-07-01

The aim of this study involved developing a temperature controller for magnetic induction hyperthermia (MIH). A closed-loop controller was applied to track a reference model to guarantee a desired temperature response. The MIH system generated an alternating magnetic field to heat a high magnetic permeability material. This wireless induction heating had few side effects when it was extensively applied to cancer treatment. The effects of hyperthermia strongly depend on the precise control of temperature. However, during the treatment process, the control performance is degraded due to severe perturbations and parameter variations. In this study, a modified self-learning fuzzy logic controller (SLFLC) with a gain tuning mechanism was implemented to obtain high control performance in a wide range of treatment situations. This implementation was performed by appropriately altering the output scaling factor of a fuzzy inverse model to adjust the control rules. In this study, the proposed SLFLC was compared to the classical self-tuning fuzzy logic controller and fuzzy model reference learning control. Additionally, the proposed SLFLC was verified by conducting in vitro experiments with porcine liver. The experimental results indicated that the proposed controller showed greater robustness and excellent adaptability with respect to the temperature control of the MIH system.

Using the Modified Checklist for Autism in Toddlers in a Well-Child Clinic in Turkey: Adapting the Screening Method Based on Culture and Setting

ERIC Educational Resources Information Center

Kara, Bülent; Mukaddes, Nahit Motavalli; Altinkaya, Isilay; Güntepe, Dilek; Gökçay, Gülbin; Özmen, Meral

2014-01-01

We aimed to adapt the Modified Checklist for Autism in Toddlers to Turkish culture. The Modified Checklist for Autism in Toddlers was filled out independently by 191 parents while they were waiting for the well-child examination of their child. A high screen-positive rate was found. Because of this high false-positive rate, a second study was done…

An Evaluation of Controller and Pilot Performance, Workload and Acceptability under a NextGen Concept for Dynamic Weather Adapted Arrival Routing

NASA Technical Reports Server (NTRS)

Johnson, Walter W.; Lachter, Joel; Brandt, Summer; Koteskey, Robert; Dao, Arik-Quang; Kraut, Josh; Ligda, Sarah; Battiste, Vernol

2012-01-01

In todays terminal operations, controller workload increases and throughput decreases when fixed standard terminal arrival routes (STARs) are impacted by storms. To circumvent this operational constraint, Prete, Krozel, Mitchell, Kim and Zou (2008) proposed to use automation to dynamically adapt arrival and departure routing based on weather predictions. The present study examined this proposal in the context of a NextGen trajectory-based operation concept, focusing on the acceptability and its effect on the controllers ability to manage traffic flows. Six controllers and twelve transport pilots participated in a human-in-the-loop simulation of arrival operations into Louisville International Airport with interval management requirements. Three types of routing structures were used: Static STARs (similar to current routing, which require the trajectories of individual aircraft to be modified to avoid the weather), Dynamic routing (automated adaptive routing around weather), and Dynamic Adjusted routing (automated adaptive routing around weather with aircraft entry time adjusted to account for differences in route length). Spacing Responsibility, whether responsibility for interval management resided with the controllers (as today), or resided with the pilot (who used a flight deck based automated spacing algorithm), was also manipulated. Dynamic routing as a whole was rated superior to static routing, especially by pilots, both in terms of workload reduction and flight path safety. A downside of using dynamic routing was that the paths flown in the dynamic conditions tended to be somewhat longer than the paths flown in the static condition.

Effect of external viscous load on head movement

NASA Technical Reports Server (NTRS)

Nam, M.-H.; Lakshminarayanan, V.; Stark, L. W.

1984-01-01

Quantitative measurements of horizontal head rotation were obtained from normal human subjects intending to make 'time optimal' trajectories between targets. By mounting large, lightweight vanes on the head, viscous damping B, up to 15 times normal could be added to the usual mechanical load of the head. With the added viscosity, the head trajectory was slowed and of larger duration (as expected) since fixed and maximal (for that amplitude) muscle forces had to accelerate the added viscous load. This decreased acceleration and velocity and longer duration movement still ensued in spite of adaptive compensation; this provided evidence that quasi-'time optimal' movements do indeed employ maximal muscle forces. The adaptation to this added load was rapid. Then the 'adapted state' subjects produced changed trajectories. The adaptation depended in part on the differing detailed instructions given to the subjects. This differential adaptation provided evidence for the existence of preprogrammed controller signals, sensitive to intended criterion, and neurologically ballistic or open loop rather than modified by feedback from proprioceptors or vision.

Variable Cadence Walking and Ground Adaptive Standing with a Powered Ankle Prosthesis

PubMed Central

Shultz, Amanda H.; Lawson, Brian E.; Goldfarb, Michael

2015-01-01

Abstract This paper describes a control approach that provides walking and standing functionality for a powered ankle prosthesis, and demonstrates the efficacy of the approach in experiments in which a unilateral transtibial amputee subject walks with the prosthesis at variable cadences, and stands on various slopes. Both controllers incorporate a finite-state structure that emulates healthy ankle joint behavior via a series of piecewise passive impedance functions. The walking controller incorporates an algorithm to modify impedance parameters based on estimated cadence, while the standing controller incorporates an algorithm to modulate the ankle equilibrium angle in order to adapt to the ground slope and user posture, and the supervisory controller selects between the walking and standing controllers. The system is shown to reproduce several essential biomechanical features of the healthy joint during walking, particularly relative to a passive prosthesis, and is shown to adapt to variable cadences. The system is also shown to adapt to slopes over a range of ± 15 deg and to provide support to the user in a manner that is biomimetic, as validated by quasi-static stiffness measurements recorded by the prosthesis. Data from standing trials indicate that the user places more weight on the powered prosthesis than on his passive prosthesis when standing on sloped surfaces, particularly at angles of 10 deg or greater. The authors also demonstrated that the prosthesis typically began providing support within 1 s of initial contact with the ground. Further, the supervisory controller was shown to be effective in switching between walking and standing, as well as in determining ground slope just prior to the transition from the standing controller to the walking controller, where the estimated ground slope was within 1.25 deg of the actual ground slope for all trials. PMID:25955789

Human heat adaptation.

PubMed

Taylor, Nigel A S

2014-01-01

In this overview, human morphological and functional adaptations during naturally and artificially induced heat adaptation are explored. Through discussions of adaptation theory and practice, a theoretical basis is constructed for evaluating heat adaptation. It will be argued that some adaptations are specific to the treatment used, while others are generalized. Regarding ethnic differences in heat tolerance, the case is put that reported differences in heat tolerance are not due to natural selection, but can be explained on the basis of variations in adaptation opportunity. These concepts are expanded to illustrate how traditional heat adaptation and acclimatization represent forms of habituation, and thermal clamping (controlled hyperthermia) is proposed as a superior model for mechanistic research. Indeed, this technique has led to questioning the perceived wisdom of body-fluid changes, such as the expansion and subsequent decay of plasma volume, and sudomotor function, including sweat habituation and redistribution. Throughout, this contribution was aimed at taking another step toward understanding the phenomenon of heat adaptation and stimulating future research. In this regard, research questions are posed concerning the influence that variations in morphological configuration may exert upon adaptation, the determinants of postexercise plasma volume recovery, and the physiological mechanisms that modify the cholinergic sensitivity of sweat glands, and changes in basal metabolic rate and body core temperature following adaptation. © 2014 American Physiological Society.

Organizational Agility Model and Simulation

DTIC Science & Technology

2011-06-01

and response profile. Also, compensatory, anticipatory , adaptive, and learning behaviours (methods) are employed to modify stiffness and resistance...The hypothetical profile in Figure 1b shows some complexity changes for a major sporting event or...classical motion tracking problem using compensatory, anticipatory , adaptive, and learning behaviours. These behaviours modify the size, resistance, and

BYSTANDERS, ADAPTIVE RESPONSES AND GENOMIC INSTABILITY - POTENTIAL MODIFIERS OF LOW-DOSE CANCER RESPONSES.

EPA Science Inventory

Bystanders, Adaptive Responses and Genomic Instability -Potential Modifiers ofLow-Dose
Cancer Responses
.
There has been a concerted effort in the field of radiation biology to better understand cellular
responses that could have an impact on the estin1ation of cancer...

Accommodating Sensor Bias in MRAC for State Tracking

NASA Technical Reports Server (NTRS)

Patre, Parag; Joshi, Suresh M.

2011-01-01

The problem of accommodating unknown sensor bias is considered in a direct model reference adaptive control (MRAC) setting for state tracking using state feedback. Sensor faults can occur during operation, and if the biased state measurements are directly used with a standard MRAC control law, neither closed-loop signal boundedness, nor asymptotic tracking can be guaranteed and the resulting tracking errors may be unbounded or unacceptably large. A modified MRAC law is proposed, which combines a bias estimator with control gain adaptation, and it is shown that signal boundedness can be accomplished, although the tracking error may not go to zero. Further, for the case wherein an asymptotically stable sensor bias estimator is available, an MRAC control law is proposed to accomplish asymptotic tracking and signal boundedness. Such a sensor bias estimator can be designed if additional sensor measurements are available, as illustrated for the case wherein bias is present in the rate gyro and airspeed measurements. Numerical example results are presented to illustrate each of the schemes.

Real-Time Stability and Control Derivative Extraction From F-15 Flight Data

NASA Technical Reports Server (NTRS)

Smith, Mark S.; Moes, Timothy R.; Morelli, Eugene A.

2003-01-01

A real-time, frequency-domain, equation-error parameter identification (PID) technique was used to estimate stability and control derivatives from flight data. This technique is being studied to support adaptive control system concepts currently being developed by NASA (National Aeronautics and Space Administration), academia, and industry. This report describes the basic real-time algorithm used for this study and implementation issues for onboard usage as part of an indirect-adaptive control system. A confidence measures system for automated evaluation of PID results is discussed. Results calculated using flight data from a modified F-15 aircraft are presented. Test maneuvers included pilot input doublets and automated inputs at several flight conditions. Estimated derivatives are compared to aerodynamic model predictions. Data indicate that the real-time PID used for this study performs well enough to be used for onboard parameter estimation. For suitable test inputs, the parameter estimates converged rapidly to sufficient levels of accuracy. The devised confidence measures used were moderately successful.

Visual-vestibular integration as a function of adaptation to space flight and return to Earth

NASA Technical Reports Server (NTRS)

Reschke, Millard R.; Bloomberg, Jacob J.; Harm, Deborah L.; Huebner, William P.; Krnavek, Jody M.; Paloski, William H.; Berthoz, Alan

1999-01-01

Research on perception and control of self-orientation and self-motion addresses interactions between action and perception . Self-orientation and self-motion, and the perception of that orientation and motion are required for and modified by goal-directed action. Detailed Supplementary Objective (DSO) 604 Operational Investigation-3 (OI-3) was designed to investigate the integrated coordination of head and eye movements within a structured environment where perception could modify responses and where response could be compensatory for perception. A full understanding of this coordination required definition of spatial orientation models for the microgravity environment encountered during spaceflight.

Stability control of a flexible maneuverable tethered space net robot

NASA Astrophysics Data System (ADS)

Zhang, Fan; Huang, Panfeng

2018-04-01

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

On the integration of reinforcement learning and approximate reasoning for control

NASA Technical Reports Server (NTRS)

Berenji, Hamid R.

1991-01-01

The author discusses the importance of strengthening the knowledge representation characteristic of reinforcement learning techniques using methods such as approximate reasoning. The ARIC (approximate reasoning-based intelligent control) architecture is an example of such a hybrid approach in which the fuzzy control rules are modified (fine-tuned) using reinforcement learning. ARIC also demonstrates that it is possible to start with an approximately correct control knowledge base and learn to refine this knowledge through further experience. On the other hand, techniques such as the TD (temporal difference) algorithm and Q-learning establish stronger theoretical foundations for their use in adaptive control and also in stability analysis of hybrid reinforcement learning and approximate reasoning-based controllers.

Data-driven adaptive fractional order PI control for PMSM servo system with measurement noise and data dropouts.

PubMed

Xie, Yuanlong; Tang, Xiaoqi; Song, Bao; Zhou, Xiangdong; Guo, Yixuan

2018-04-01

In this paper, data-driven adaptive fractional order proportional integral (AFOPI) control is presented for permanent magnet synchronous motor (PMSM) servo system perturbed by measurement noise and data dropouts. The proposed method directly exploits the closed-loop process data for the AFOPI controller design under unknown noise distribution and data missing probability. Firstly, the proposed method constructs the AFOPI controller tuning problem as a parameter identification problem using the modified l p norm virtual reference feedback tuning (VRFT). Then, iteratively reweighted least squares is integrated into the l p norm VRFT to give a consistent compensation solution for the AFOPI controller. The measurement noise and data dropouts are estimated and eliminated by feedback compensation periodically, so that the AFOPI controller is updated online to accommodate the time-varying operating conditions. Moreover, the convergence and stability are guaranteed by mathematical analysis. Finally, the effectiveness of the proposed method is demonstrated both on simulations and experiments implemented on a practical PMSM servo system. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

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

Scheinker, Alexander

A recently developed form of extremum seeking for time-varying systems is implemented in hardware for the resonance control of radio-frequency cavities without phase measurements. Normal conducting RF cavity resonance control is performed via a slug tuner, while superconducting TESLA-type cavity resonance control is performed via piezo actuators. The controller maintains resonance by minimizing reflected power by utilizing model-independent adaptive feedback. Unlike standard phase-measurement-based resonance control, the presented approach is not sensitive to arbitrary phase shifts of the RF signals due to temperature-dependent cable length or phasemeasurement hardware changes. The phase independence of this method removes common slowly varying drifts andmore » required periodic recalibration of phase-based methods. A general overview of the adaptive controller is presented along with the proof of principle experimental results at room temperature. Lastly, this method allows us to both maintain a cavity at a desired resonance frequency and also to dynamically modify its resonance frequency to track the unknown time-varying frequency of an RF source, thereby maintaining maximal cavity field strength, based only on power-level measurements.« less

Eye-Hand Coordination during Visuomotor Adaptation with Different Rotation Angles

PubMed Central

Rentsch, Sebastian; Rand, Miya K.

2014-01-01

This study examined adaptive changes of eye-hand coordination during a visuomotor rotation task. Young adults made aiming movements to targets on a horizontal plane, while looking at the rotated feedback (cursor) of hand movements on a monitor. To vary the task difficulty, three rotation angles (30°, 75°, and 150°) were tested in three groups. All groups shortened hand movement time and trajectory length with practice. However, control strategies used were different among groups. The 30° group used proportionately more implicit adjustments of hand movements than other groups. The 75° group used more on-line feedback control, whereas the 150° group used explicit strategic adjustments. Regarding eye-hand coordination, timing of gaze shift to the target was gradually changed with practice from the late to early phase of hand movements in all groups, indicating an emerging gaze-anchoring behavior. Gaze locations prior to the gaze anchoring were also modified with practice from the cursor vicinity to an area between the starting position and the target. Reflecting various task difficulties, these changes occurred fastest in the 30° group, followed by the 75° group. The 150° group persisted in gazing at the cursor vicinity. These results suggest that the function of gaze control during visuomotor adaptation changes from a reactive control for exploring the relation between cursor and hand movements to a predictive control for guiding the hand to the task goal. That gaze-anchoring behavior emerged in all groups despite various control strategies indicates a generality of this adaptive pattern for eye-hand coordination in goal-directed actions. PMID:25333942

An experimental SMI adaptive antenna array simulator for weak interfering signals

NASA Technical Reports Server (NTRS)

Dilsavor, Ronald S.; Gupta, Inder J.

1991-01-01

An experimental sample matrix inversion (SMI) adaptive antenna array for suppressing weak interfering signals is described. The experimental adaptive array uses a modified SMI algorithm to increase the interference suppression. In the modified SMI algorithm, the sample covariance matrix is redefined to reduce the effect of thermal noise on the weights of an adaptive array. This is accomplished by subtracting a fraction of the smallest eigenvalue of the original covariance matrix from its diagonal entries. The test results obtained using the experimental system are compared with theoretical results. The two show a good agreement.

Modified Checklist for Autism in Toddlers: Cross-Cultural Adaptation and Validation in Spain

ERIC Educational Resources Information Center

Canal-Bedia, Ricardo; Garcia-Primo, Patricia; Martin-Cilleros, Maria Victoria; Santos-Borbujo, Jose; Guisuraga-Fernandez, Zoila; Herraez-Garcia, Lorena; Herraez-Garcia, Maria del Mar; Boada-Munoz, Leticia; Fuentes-Biggi, Joaquin; Posada-de La Paz, Manuel

2011-01-01

Early detection and treatment have been shown to be effective in reducing disability severity caused by Autistic Spectrum Disorders (ASDs). As Spanish pediatricians have no detection tool, the Modified Checklist for Autism in Toddlers (M-CHAT) was first translated into and culturally adapted to Spanish. Validity and reliability studies were…

Capture, Unfolding, and Detection of Individual tRNA Molecules Using a Nanopore Device

PubMed Central

Smith, Andrew M.; Abu-Shumays, Robin; Akeson, Mark; Bernick, David L.

2015-01-01

Transfer RNAs (tRNA) are the most common RNA molecules in cells and have critical roles as both translators of the genetic code and regulators of protein synthesis. As such, numerous methods have focused on studying tRNA abundance and regulation, with the most widely used methods being RNA-seq and microarrays. Though revolutionary to transcriptomics, these assays are limited by an inability to encode tRNA modifications in the requisite cDNA. These modifications are abundant in tRNA and critical to their function. Here, we describe proof-of-concept experiments where individual tRNA molecules are examined as linear strands using a biological nanopore. This method utilizes an enzymatically ligated synthetic DNA adapter to concentrate tRNA at the lipid bilayer of the nanopore device and efficiently denature individual tRNA molecules, as they are pulled through the α-hemolysin (α-HL) nanopore. Additionally, the DNA adapter provides a loading site for ϕ29 DNA polymerase (ϕ29 DNAP), which acts as a brake on the translocating tRNA. This increases the dwell time of adapted tRNA in the nanopore, allowing us to identify the region of the nanopore signal that is produced by the translocating tRNA itself. Using adapter-modified Escherichia coli tRNAfMet and tRNALys, we show that the nanopore signal during controlled translocation is dependent on the identity of the tRNA. This confirms that adapter-modified tRNA can translocate end-to-end through nanopores and provide the foundation for future work in direct sequencing of individual transfer RNA with a nanopore-based device. PMID:26157798

Developing a consumer evaluation tool of weight control strategy advertisements on the Internet.

PubMed

Luevorasirikul, Kanokrat; Gray, Nicola J; Anderson, Claire W

2008-06-01

To develop two evaluation tools for weight loss and weight gain advertisements on the Internet in order to help consumers to evaluate the quality of information within these advertisements. One hundred websites identified by Internet search engines for weight loss and weight gain strategies (50 websites each) were evaluated using two specific scoring instruments, developed by adapting questions from the 'DISCERN' tool and reviewing all related weight control guidelines and advertising regulations. The validity and reliability of the adapted tools were tested. Our evaluation tools rated the information from most websites as poor quality (70%). In the case of weight loss strategies, statements about rapid (18%) and permanent (28%) weight loss caused concern as well as lack of sensible advice about dieting and a lack of product warnings (84%). Safety concerns relating to weight gain products were the lack of warnings about side effects in products containing steroids and creatine (92%). The adapted tools exhibited acceptable validity and reliability. Quality of information within weight control advertisements on the Internet was generally poor. Problems of false claims, little advice on healthy ways to modify weight and few warnings on side effects have been highlighted in this study.

Organizational Leadership and Adaptive Reserve in Blood Pressure Control: The Heart Health NOW Study.

PubMed

Henderson, Kamal H; DeWalt, Darren A; Halladay, Jacquie; Weiner, Bryan J; Kim, Jung I; Fine, Jason; Cykert, Samuel

2018-04-01

Our purpose was to assess whether a practice's adaptive reserve and high leadership capability in quality improvement are associated with population blood pressure control. We divided practices into quartiles of blood pressure control performance and considered the top quartile as the benchmark for comparison. Using abstracted clinical data from electronic health records, we performed a cross-sectional study to assess the association of top quartile hypertension control and (1) the baseline practice adaptive reserve (PAR) scores and (2) baseline practice leadership scores, using modified Poisson regression models adjusting for practice-level characteristics. Among 181 practices, 46 were in the top quartile, which averaged 68% or better blood pressure control. Practices with higher PAR scores compared with lower PAR scores were not more likely to reside in the top quartile of performance (prevalence ratio [PR] = 1.92 for highest quartile; 95% CI, 0.9-4.1). Similarly, high quality improvement leadership capability compared with lower capability did not predict better blood pressure control performance (PR = 0.94; 95% CI, 0.57-1.56). Practices with higher proportions of commercially insured patients were more likely than practices with lower proportions of commercially insured patients to have top quartile performance (37% vs 26%, P =.002), whereas lower proportions of the uninsured (8% vs 14%, P =.055) were associated with better performance. Our findings show that adaptive reserve and leadership capability in quality improvement implementation are not statistically associated with achieving top quartile practice-level hypertension control at baseline in the Heart Health NOW project. Our findings, however, may be limited by a lack of patient-related factors and small sample size to preclude strong conclusions. © 2018 Annals of Family Medicine, Inc.

The Formative Method for Adapting Psychotherapy (FMAP): A community-based developmental approach to culturally adapting therapy

PubMed Central

Hwang, Wei-Chin

2010-01-01

How do we culturally adapt psychotherapy for ethnic minorities? Although there has been growing interest in doing so, few therapy adaptation frameworks have been developed. The majority of these frameworks take a top-down theoretical approach to adapting psychotherapy. The purpose of this paper is to introduce a community-based developmental approach to modifying psychotherapy for ethnic minorities. The Formative Method for Adapting Psychotherapy (FMAP) is a bottom-up approach that involves collaborating with consumers to generate and support ideas for therapy adaptation. It involves 5-phases that target developing, testing, and reformulating therapy modifications. These phases include: (a) generating knowledge and collaborating with stakeholders (b) integrating generated information with theory and empirical and clinical knowledge, (c) reviewing the initial culturally adapted clinical intervention with stakeholders and revising the culturally adapted intervention, (d) testing the culturally adapted intervention, and (e) finalizing the culturally adapted intervention. Application of the FMAP is illustrated using examples from a study adapting psychotherapy for Chinese Americans, but can also be readily applied to modify therapy for other ethnic groups. PMID:20625458

Toward Viral Vaccine Development: A Modified Venezuelan Equine Encephalitis Replicon as Strategy for Optimizing Immunogenicity

DTIC Science & Technology

2007-04-13

and termination are indicated by triangles and diamonds , respectively. Adapted from Rice and Frolov 1996. 9 10 Figure 1.3: Schematic...2001 to 2005 and were associated with increased incidence of acute respiratory distress syndrome in conjunction with encephalitis (5-7, 80). Higher...Temporal association of cellular immune responses with the initial control of viremia in primary human immunodeficiency virus type 1 syndrome

Dissociation between decision-making under risk and decision-making under ambiguity in premanifest and manifest Huntington's disease.

PubMed

Adjeroud, Najia; Besnard, Jeremy; Verny, Christophe; Prundean, Adriana; Scherer, Clarisse; Gohier, Bénédicte; Bonneau, Dominique; Massioui, Nicole El; Allain, Philippe

2017-08-01

We investigated decision-making under ambiguity (DM-UA) and decision making under risk (DM-UR) in individuals with premanifest and manifest Huntington's disease (HD). Twenty individuals with premanifest HD and 23 individuals with manifest HD, on one hand, and 39 healthy individuals divided into two control groups, on the other, undertook a modified version of the Iowa Gambling Task (IGT), an adaptation of a DM-UA task, and a modified version of the Game of Dice Task (GDT), an adaptation of a DM-UR task. Participants also filled in a questionnaire of impulsivity and responded to cognitive tests specifically designed to assess executive functions. Compared to controls, individuals with premanifest HD were unimpaired in performing executive tests as well as in decision-making tasks, except for the Stroop task. In contrast, individuals with manifest HD were impaired in both the IGT and executive tasks, but not in the GDT. No sign of impulsivity was observed in individuals with premanifest or manifest HD. Our results suggest that the progression of HD impairs DM-UA without affecting DM-UR, and indicate that decision-making abilities are preserved during the premanifest stage of HD. Copyright © 2017 Elsevier Ltd. All rights reserved.

Balancing Vibrations at Harmonic Frequencies by Injecting Harmonic Balancing Signals into the Armature of a Linear Motor/Alternator Coupled to a Stirling Machine

NASA Technical Reports Server (NTRS)

Holliday, Ezekiel S. (Inventor)

2014-01-01

Vibrations at harmonic frequencies are reduced by injecting harmonic balancing signals into the armature of a linear motor/alternator coupled to a Stirling machine. The vibrations are sensed to provide a signal representing the mechanical vibrations. A harmonic balancing signal is generated for selected harmonics of the operating frequency by processing the sensed vibration signal with adaptive filter algorithms of adaptive filters for each harmonic. Reference inputs for each harmonic are applied to the adaptive filter algorithms at the frequency of the selected harmonic. The harmonic balancing signals for all of the harmonics are summed with a principal control signal. The harmonic balancing signals modify the principal electrical drive voltage and drive the motor/alternator with a drive voltage component in opposition to the vibration at each harmonic.

Systematic, Multimethod Assessment of Adaptations Across Four Diverse Health Systems Interventions.

PubMed

Rabin, Borsika A; McCreight, Marina; Battaglia, Catherine; Ayele, Roman; Burke, Robert E; Hess, Paul L; Frank, Joseph W; Glasgow, Russell E

2018-01-01

Many health outcomes and implementation science studies have demonstrated the importance of tailoring evidence-based care interventions to local context to improve fit. By adapting to local culture, history, resources, characteristics, and priorities, interventions are more likely to lead to improved outcomes. However, it is unclear how best to adapt evidence-based programs and promising innovations. There are few guides or examples of how to best categorize or assess health-care adaptations, and even fewer that are brief and practical for use by non-researchers. This study describes the importance and potential of assessing adaptations before, during, and after the implementation of health systems interventions. We present a promising multilevel and multimethod approach developed and being applied across four different health systems interventions. Finally, we discuss implications and opportunities for future research. The four case studies are diverse in the conditions addressed, interventions, and implementation strategies. They include two nurse coordinator-based transition of care interventions, a data and training-driven multimodal pain management project, and a cardiovascular patient-reported outcomes project, all of which are using audit and feedback. We used the same modified adaptation framework to document changes made to the interventions and implementation strategies. To create the modified framework, we started with the adaptation and modification model developed by Stirman and colleagues and expanded it by adding concepts from the RE-AIM framework. Our assessments address the intuitive domains of Who, How, When, What, and Why to classify and organize adaptations. For each case study, we discuss how the modified framework was operationalized, the multiple methods used to collect data, results to date and approaches utilized for data analysis. These methods include a real-time tracking system and structured interviews at key times during the intervention. We provide descriptive data on the types and categories of adaptations made and discuss lessons learned. The multimethod approaches demonstrate utility across diverse health systems interventions. The modified adaptations model adequately captures adaptations across the various projects and content areas. We recommend systematic documentation of adaptations in future clinical and public health research and have made our assessment materials publicly available.

Center for Adaptive Optics | Home

Science.gov Websites

Center for Adaptive Optics A University of California Science and Technology Center home Directions to The Center for Adaptive Optics Building Directions to the Center for Adaptive Optics Building * Seaway Inn * West Cliff Inn Last Modified: Apr 3, 2012 Center for Adaptive Optics | Search | The Center

Learning before leaping: integration of an adaptive study design process prior to initiation of BetterBirth, a large-scale randomized controlled trial in Uttar Pradesh, India.

PubMed

Hirschhorn, Lisa Ruth; Semrau, Katherine; Kodkany, Bhala; Churchill, Robyn; Kapoor, Atul; Spector, Jonathan; Ringer, Steve; Firestone, Rebecca; Kumar, Vishwajeet; Gawande, Atul

2015-08-14

Pragmatic and adaptive trial designs are increasingly used in quality improvement (QI) interventions to provide the strongest evidence for effective implementation and impact prior to broader scale-up. We previously showed that an on-site coaching intervention focused on the World Health Organization Safe Childbirth Checklist (SCC) improved performance of essential birth practices (EBPs) in one facility in Karnataka, India. We report on the process and outcomes of adapting the intervention prior to larger-scale implementation in a randomized controlled trial in Uttar Pradesh (UP), India. Initially, we trained a local team of physicians and nurses to coach birth attendants in SCC use at two public facilities for 4-6 weeks. Trained observers evaluated adherence to EBPs before and after coaching. Using mixed methods and a systematic adaptation process, we modified and strengthened the intervention. The modified intervention was implemented in three additional facilities. Pre/post-change in EBP prevalence aggregated across facilities was analyzed. In the first two facilities, limited improvement was seen in EBPs with the exception of post-partum oxytocin. Checklists were used <25 % of observations. We identified challenges in physicians coaching nurses, need to engage district and facility leadership to address system gaps, and inadequate strategy for motivating SCC uptake. Revisions included change to peer-to-peer coaching (nurse to nurse, physician to physician); strengthened coach training on behavior and system change; adapted strategy for effective leadership engagement; and an explicit motivation strategy to enhance professional pride and effectiveness. These modifications resulted in improvement in multiple EBPs from baseline including taking maternal blood pressure (0 to 16 %), post-partum oxytocin (36 to 97 %), early breastfeeding initiation (3 to 64 %), as well as checklist use (range 32 to 88 %), all p < 0.01. Further adaptations were implemented to increase the effectiveness prior to full trial launch. The adaptive study design of implementation, evaluation, and feedback drove iterative redesign and successfully developed a SCC-focused coaching intervention that improved EBPs in UP facilities. This work was critical to develop a replicable BetterBirth package tailored to the local context. The multi-center pragmatic trial is underway measuring impact of the BetterBirth program on EBP and maternal-neonatal morbidity and mortality. NCT02148952 .

Characterization of Extracellular Polymeric Substances Produced by Pseudomonas fragi Under Air and Modified Atmosphere Packaging.

PubMed

Wang, Guang-Yu; Ma, Fang; Wang, Hu-Hu; Xu, Xing-Lian; Zhou, Guang-Hong

2017-09-01

Extracellular polymeric substances (EPS) play an important role in bacterial biochemical properties. The characteristics of EPS from 2 strains of Pseudomonas fragi cultured in meat aerobically (control) and in modified atmosphere packaging (MAP) were studied. The amount and components of EPS, the surface properties, and the effect on biofilm formation of several spoilage organisms were evaluated. The results showed that MAP inhibited the growth of the P. fragi strains. Compared with the control, more loose and less bound EPS (containing protein and carbohydrate) were produced by P. fragi in MAP samples. MAP also caused increased cell autoaggregation and surface hydrophobicity. After the removal of the EPS, the surface property changes were strain-dependent, suggesting that membrane compositions were also changed. In addition, the EPS displayed significant antibiofilm activity on Pseudomonas fluorescens and Serratia liquefaciens. In conclusion, P. fragi strains not only modified the amount, components, and surface properties of EPS but also changed the cell membrane compositions to adapt to MAP stress. Moreover, EPS may play an important role in microbial community competitions. © 2017 Institute of Food Technologists®.

Learning algorithms for human-machine interfaces.

PubMed

Danziger, Zachary; Fishbach, Alon; Mussa-Ivaldi, Ferdinando A

2009-05-01

The goal of this study is to create and examine machine learning algorithms that adapt in a controlled and cadenced way to foster a harmonious learning environment between the user and the controlled device. To evaluate these algorithms, we have developed a simple experimental framework. Subjects wear an instrumented data glove that records finger motions. The high-dimensional glove signals remotely control the joint angles of a simulated planar two-link arm on a computer screen, which is used to acquire targets. A machine learning algorithm was applied to adaptively change the transformation between finger motion and the simulated robot arm. This algorithm was either LMS gradient descent or the Moore-Penrose (MP) pseudoinverse transformation. Both algorithms modified the glove-to-joint angle map so as to reduce the endpoint errors measured in past performance. The MP group performed worse than the control group (subjects not exposed to any machine learning), while the LMS group outperformed the control subjects. However, the LMS subjects failed to achieve better generalization than the control subjects, and after extensive training converged to the same level of performance as the control subjects. These results highlight the limitations of coadaptive learning using only endpoint error reduction.

Learning Algorithms for Human–Machine Interfaces

PubMed Central

Fishbach, Alon; Mussa-Ivaldi, Ferdinando A.

2012-01-01

The goal of this study is to create and examine machine learning algorithms that adapt in a controlled and cadenced way to foster a harmonious learning environment between the user and the controlled device. To evaluate these algorithms, we have developed a simple experimental framework. Subjects wear an instrumented data glove that records finger motions. The high-dimensional glove signals remotely control the joint angles of a simulated planar two-link arm on a computer screen, which is used to acquire targets. A machine learning algorithm was applied to adaptively change the transformation between finger motion and the simulated robot arm. This algorithm was either LMS gradient descent or the Moore–Penrose (MP) pseudoinverse transformation. Both algorithms modified the glove-to-joint angle map so as to reduce the endpoint errors measured in past performance. The MP group performed worse than the control group (subjects not exposed to any machine learning), while the LMS group outperformed the control subjects. However, the LMS subjects failed to achieve better generalization than the control subjects, and after extensive training converged to the same level of performance as the control subjects. These results highlight the limitations of coadaptive learning using only endpoint error reduction. PMID:19203886

Dual control and prevention of the turn-off phenomenon in a class of mimo systems

NASA Technical Reports Server (NTRS)

Mookerjee, P.; Bar-Shalom, Y.; Molusis, J. A.

1985-01-01

A recently developed methodology of adaptive dual control based upon sensitivity functions is applied here to a multivariable input-output model. The plant has constant but unknown parameters. It represents a simplified linear version of the relationship between the vibration output and the higher harmonic control input for a helicopter. The cautious and the new dual controller are examined. In many instances, the cautious controller is seen to turn off. The new dual controller modifies the cautious control design by numerator and denominator correction terms which depend upon the sensitivity functions of the expected future cost and avoids the turn-off and burst phenomena. Monte Carlo simulations and statistical tests of significance indicate the superiority of the dual controller over the cautious and the heuristic certainity equivalence controllers.

Method for removing tilt control in adaptive optics systems

DOEpatents

Salmon, Joseph Thaddeus

1998-01-01

A new adaptive optics system and method of operation, whereby the method removes tilt control, and includes the steps of using a steering mirror to steer a wavefront in the desired direction, for aiming an impinging aberrated light beam in the direction of a deformable mirror. The deformable mirror has its surface deformed selectively by means of a plurality of actuators, and compensates, at least partially, for existing aberrations in the light beam. The light beam is split into an output beam and a sample beam, and the sample beam is sampled using a wavefront sensor. The sampled signals are converted into corresponding electrical signals for driving a controller, which, in turn, drives the deformable mirror in a feedback loop in response to the sampled signals, for compensating for aberrations in the wavefront. To this purpose, a displacement error (gradient) of the wavefront is measured, and adjusted by a modified gain matrix, which satisfies the following equation: G'=(I-X(X.sup.T X).sup.-1 X.sup.T)G(I-A)

Adaptive texture filtering for defect inspection in ultrasound images

NASA Astrophysics Data System (ADS)

Zmola, Carl; Segal, Andrew C.; Lovewell, Brian; Nash, Charles

1993-05-01

The use of ultrasonic imaging to analyze defects and characterize materials is critical in the development of non-destructive testing and non-destructive evaluation (NDT/NDE) tools for manufacturing. To develop better quality control and reliability in the manufacturing environment advanced image processing techniques are useful. For example, through the use of texture filtering on ultrasound images, we have been able to filter characteristic textures from highly-textured C-scan images of materials. The materials have highly regular characteristic textures which are of the same resolution and dynamic range as other important features within the image. By applying texture filters and adaptively modifying their filter response, we have examined a family of filters for removing these textures.

Effects of ordinary and adaptive toys on pre-school children with developmental disabilities.

PubMed

Hsieh, Hsieh-Chun

2008-01-01

Toys help children in mastering developmental tasks. This study investigated toy effect on children with developmental disabilities as they engage in using ordinary and adaptive toys. A single-subject design was used to identify the effects on their toy play abilities. Differences in toy effects between playing ordinary and adaptive toys were examined. Three special education teachers chose ordinary toys and modified ordinary toys. Modified ordinary toys, i.e., adaptive toys, were designed according to the individual disabilities of participating children, treatment goals, and the toy types. Three children with developmental disabilities from pre-schools in Taiwan were enrolled. Appropriate participation of three pre-schoolers increased dramatically in playing adaptive toys during intervention phase. The toy effects demonstrate that when using adaptive toys, children with developmental disabilities may response better during toy play sessions.

Changes in Neuronal Signaling and Cell Stress Response Pathways are Associated with a Multigenic Response of Drosophila melanogaster to DDT Selection

PubMed Central

Coates, Brad S; Sun, Weilin; Clark, John M; Pittendrigh, Barry R

2017-01-01

Abstract The adaptation of insect populations to insecticidal control is a continual threat to human health and sustainable agricultural practices, but many complex genomic mechanisms involved in this adaption remain poorly understood. This study applied a systems approach to investigate the interconnections between structural and functional variance in response to dichlorodiphenyltrichloroethane (DDT) within the Drosophila melanogaster strain 91-R. Directional selection in 6 selective sweeps coincided with constitutive gene expression differences in DDT resistant flies, including the most highly upregulated transcript, Unc-115 b, which plays a central role in axon guidance, and the most highly downregulated transcript, the angiopoietin-like CG31832, which is involved in directing vascular branching and dendrite outgrowth but likely may be under trans-regulatory control. Direct functions and protein–protein interactions mediated by differentially expressed transcripts control changes in cell migration, signal transduction, and gene regulatory cascades that impact the nervous system. Although changes to cellular stress response pathways involve 8 different cytochrome P450s, stress response, and apoptosis is controlled by a multifacetted regulatory mechanism. These data demonstrate that DDT selection in 91-R may have resulted in genome-wide adaptations that impacts genetic and signal transduction pathways that converge to modify stress response, cell survival, and neurological functions. This study implicates the involvement of a multigenic mechanism in the adaptation to a chemical insecticide, which impact interconnected regulatory cascades. We propose that DDT selection within 91-R might act systemically, wherein pathway interactions function to reinforce the epistatic effects of individual adaptive changes on an additive or nonadditive basis. PMID:29211847

Postural control and perceptive configuration: influence of expertise in gymnastics.

PubMed

Gautier, Geoffroy; Thouvarecq, Régis; Vuillerme, Nicolas

2008-07-01

The purpose of the present experiment was to investigate how postural adaptations to the perceptive configuration are modified by specific gymnastics experience. Two groups, one expert in gymnastics and the other non-expert, had to maintain the erected posture while optical flow was imposed as follows: 20s motionless, 30s approaching motion, and 20s motionless. The centre of pressure and head displacements were analysed. The postural adaptations were characterised by the variability of movements for the flow conditions and by the postural latencies for the flow transitions. The results showed that the gymnasts tended to minimise their body movements and were more stationary (head) but not more stable (COP) than the non-gymnasts. These results suggest that gymnastics experience develops a specific postural adaptability relative to the perceptive configuration. We conclude that a specific postural experience could be considered as an intrinsic constraint, which leads to modification in the patterns of functional adaptation in the perceptive motor space.

Considering the Use of General and Modified Assessment Items in Computerized Adaptive Testing

ERIC Educational Resources Information Center

Wyse, Adam E.; Albano, Anthony D.

2015-01-01

This article used several data sets from a large-scale state testing program to examine the feasibility of combining general and modified assessment items in computerized adaptive testing (CAT) for different groups of students. Results suggested that several of the assumptions made when employing this type of mixed-item CAT may not be met for…

Elementary School Students' Interaction with the Planned Curriculum Through Their Valuing, Adapting, and Modifying Subject Matter.

ERIC Educational Resources Information Center

Zuga, Karen F.

Ways in which elementary school students value, adapt, and modify the curriculum are revealed by reporting statements of children in grades 2 through 4 in a midwestern parochial school. Over 250 hours of observation as well as interviews with students, teachers, parents, and the principal formed the basis of research. Data were assembled through…

Adaptive robust motion trajectory tracking control of pneumatic cylinders with LuGre model-based friction compensation

NASA Astrophysics Data System (ADS)

Meng, Deyuan; Tao, Guoliang; Liu, Hao; Zhu, Xiaocong

2014-07-01

Friction compensation is particularly important for motion trajectory tracking control of pneumatic cylinders at low speed movement. However, most of the existing model-based friction compensation schemes use simple classical models, which are not enough to address applications with high-accuracy position requirements. Furthermore, the friction force in the cylinder is time-varying, and there exist rather severe unmodelled dynamics and unknown disturbances in the pneumatic system. To deal with these problems effectively, an adaptive robust controller with LuGre model-based dynamic friction compensation is constructed. The proposed controller employs on-line recursive least squares estimation (RLSE) to reduce the extent of parametric uncertainties, and utilizes the sliding mode control method to attenuate the effects of parameter estimation errors, unmodelled dynamics and disturbances. In addition, in order to realize LuGre model-based friction compensation, the modified dual-observer structure for estimating immeasurable friction internal state is developed. Therefore, a prescribed motion tracking transient performance and final tracking accuracy can be guaranteed. Since the system model uncertainties are unmatched, the recursive backstepping design technology is applied. In order to solve the conflicts between the sliding mode control design and the adaptive control design, the projection mapping is used to condition the RLSE algorithm so that the parameter estimates are kept within a known bounded convex set. Finally, the proposed controller is tested for tracking sinusoidal trajectories and smooth square trajectory under different loads and sudden disturbance. The testing results demonstrate that the achievable performance of the proposed controller is excellent and is much better than most other studies in literature. Especially when a 0.5 Hz sinusoidal trajectory is tracked, the maximum tracking error is 0.96 mm and the average tracking error is 0.45 mm. This paper constructs an adaptive robust controller which can compensate the friction force in the cylinder.

Effects of Flood Control Strategies on Flood Resilience Under Sociohydrological Disturbances

NASA Astrophysics Data System (ADS)

Sung, Kyungmin; Jeong, Hanseok; Sangwan, Nikhil; Yu, David J.

2018-04-01

A community capacity to cope with flood hazards, or community flood resilience, emerges from the interplay of hydrological and social processes. This interplay can be significantly influenced by the flood control strategy adopted by a society, i.e., how a society sets its desired flood protection level and strives to achieve this goal. And this interplay can be further complicated by rising land-sea level differences, seasonal water level fluctuations, and economic change. But not much research has been done on how various forms of flood control strategies affect human-flood interactions under these disturbances and therefore flood resilience in the long run. The current study is an effort to address these issues by developing a conceptual model of human-flood interaction mediated by flood control strategies. Our model extends the existing model of Yu et al. (2017), who investigated the flood resilience of a community-based flood protection system in coastal Bangladesh. The major extensions made in this study are inclusions of various forms of flood control strategies (both adaptive and nonadaptive ones), the challenge of rising land-sea level differences, and various high tide level scenarios generated from modifying the statistical variances and averages. Our results show that adaptive forms of flood control strategies tend to outperform nonadaptive ones for maintaining the model community's flood protection system. Adaptive strategies that dynamically adjust target flood protection levels through close monitoring of flood damages and social memories of flood risk can help the model community deal with various disturbances.

50 CFR 217.88 - Renewal of Letters of Authorization and adaptive management.

Code of Federal Regulations, 2014 CFR

2014-10-01

... to the adaptive management component of these regulations, provided that: (1) NMFS is notified that... that modifications are appropriate pursuant to the adaptive management component of these regulations...) Adaptive Management—NMFS may modify or augment the existing mitigation or monitoring measures (after...

50 CFR 217.88 - Renewal of Letters of Authorization and adaptive management.

Code of Federal Regulations, 2012 CFR

2012-10-01

... to the adaptive management component of these regulations, provided that: (1) NMFS is notified that... that modifications are appropriate pursuant to the adaptive management component of these regulations...) Adaptive Management—NMFS may modify or augment the existing mitigation or monitoring measures (after...

50 CFR 217.88 - Renewal of Letters of Authorization and adaptive management.

Code of Federal Regulations, 2013 CFR

2013-10-01

... to the adaptive management component of these regulations, provided that: (1) NMFS is notified that... that modifications are appropriate pursuant to the adaptive management component of these regulations...) Adaptive Management—NMFS may modify or augment the existing mitigation or monitoring measures (after...

Chaos, Chaos Control and Synchronization of a Gyrostat System

NASA Astrophysics Data System (ADS)

GE, Z.-M.; LIN, T.-N.

2002-03-01

The dynamic behavior of a gyrostat system subjected to external disturbance is studied in this paper. By applying numerical results, phase diagrams, power spectrum, period-T maps, and Lyapunov exponents are presented to observe periodic and choatic motions. The effect of the parameters changed in the system can be found in the bifurcation and parametric diagrams. For global analysis, the basins of attraction of each attractor of the system are located by employing the modified interpolated cell mapping (MICM) method. Several methods, the delayed feedback control, the addition of constant torque, the addition of periodic force, the addition of periodic impulse torque, injection of dither signal control, adaptive control algorithm (ACA) control and bang-bang control are used to control chaos effectively. Finally, synchronization of chaos in the gyrostat system is studied.

TRANSLATION TO PORTUGUESE LANGUAGE AND CROSS-CULTURAL ADAPTATION OF THE MODIFIED ROWE SCORE FOR OVERHEAD ATHLETES

PubMed Central

Marcondes, Freddy Beretta; de Vasconcelos, Rodrigo Antunes; Marchetto, Adriano; de Andrade, André Luis Lugnani; Filho, Américo Zoppi; Etchebehere, Maurício

2015-01-01

Objetctive: Study was to translate and culturally adapt the modified Rowe score for overhead athletes. Methods: The translation and cultural adaptation process initially involved the stages of translation, synthesis, back-translation, and revision by the Translation Group. It was than created the pre-final version of the questionnaire, being the areas “function” and “pain” applied to 20 athletes that perform overhead movements and that suffered SLAP lesions in the dominant shoulder and the areas “active compression test and anterior apprehension test” and “motion” were applied to 15 health professionals. Results: During the translation process there were made little modifications in the questionnaire in order to adapt it to Brazilian culture, without changing the semantics and the idiomatic concept originally described. Conclusion: The questionnaire was easily understood by the subjects of the study, being possible to obtain the Brazilian version of the modified Rowe score for overhead athletes that underwent surgical treatment of the SLAP lesion. PMID:27047903

Cross-cultural adaptation and validation of a Bengali version of the modified fibromyalgia impact questionnaire

PubMed Central

2012-01-01

Background Currently, no validated instruments are available to measure the health status of Bangladeshi patients with fibromyalgia (FM). The aims of this study were to cross-culturally adapt the modified Fibromyalgia Impact Questionnaire (FIQ) into Bengali (B-FIQ) and to test its validity and reliability in Bangladeshi patients with FM. Methods The FIQ was translated following cross-cultural adaptation guidelines and pretested in 30 female patients with FM. Next, the adapted B-FIQ was physician-administered to 102 consecutive female FM patients together with the Health Assessment Questionnaire (HAQ), selected subscales of the SF-36, and visual analog scales for current clinical symptoms. A tender point count (TPC) was performed by an experienced rheumatologist. Forty randomly selected patients completed the B-FIQ again after 7 days. Two control groups of 50 healthy people and 50 rheumatoid arthritis (RA) patients also completed the B-FIQ. Results For the final B-FIQ, five physical function sub-items were replaced with culturally appropriate equivalents. Internal consistency was adequate for both the 11-item physical function subscale (α = 0.73) and the total scale (α = 0.83). With exception of the physical function subscale, expected correlations were generally observed between the B-FIQ items and selected subscales of the SF-36, HAQ, clinical symptoms, and TPC. The B-FIQ was able to discriminate between FM patients and healthy controls and between FM patients and RA patients. Test-retest reliability was adequate for the physical function subscale (r = 0.86) and individual items (r = 0.73-0.86), except anxiety (r = 0.27) and morning tiredness (r = 0.64). Conclusion This study supports the reliability and validity of the B-FIQ as a measure of functional disability and health status in Bangladeshi women with FM. PMID:22925458

Loss of 'complexity' and aging. Potential applications of fractals and chaos theory to senescence

NASA Technical Reports Server (NTRS)

Lipsitz, L. A.; Goldberger, A. L.

1992-01-01

The concept of "complexity," derived from the field of nonlinear dynamics, can be adapted to measure the output of physiologic processes that generate highly variable fluctuations resembling "chaos." We review data suggesting that physiologic aging is associated with a generalized loss of such complexity in the dynamics of healthy organ system function and hypothesize that such loss of complexity leads to an impaired ability to adapt to physiologic stress. This hypothesis is supported by observations showing an age-related loss of complex variability in multiple physiologic processes including cardiovascular control, pulsatile hormone release, and electroencephalographic potentials. If further research supports this hypothesis, measures of complexity based on chaos theory and the related geometric concept of fractals may provide new ways to monitor senescence and test the efficacy of specific interventions to modify the age-related decline in adaptive capacity.

hp-Adaptive time integration based on the BDF for viscous flows

NASA Astrophysics Data System (ADS)

Hay, A.; Etienne, S.; Pelletier, D.; Garon, A.

2015-06-01

This paper presents a procedure based on the Backward Differentiation Formulas of order 1 to 5 to obtain efficient time integration of the incompressible Navier-Stokes equations. The adaptive algorithm performs both stepsize and order selections to control respectively the solution accuracy and the computational efficiency of the time integration process. The stepsize selection (h-adaptivity) is based on a local error estimate and an error controller to guarantee that the numerical solution accuracy is within a user prescribed tolerance. The order selection (p-adaptivity) relies on the idea that low-accuracy solutions can be computed efficiently by low order time integrators while accurate solutions require high order time integrators to keep computational time low. The selection is based on a stability test that detects growing numerical noise and deems a method of order p stable if there is no method of lower order that delivers the same solution accuracy for a larger stepsize. Hence, it guarantees both that (1) the used method of integration operates inside of its stability region and (2) the time integration procedure is computationally efficient. The proposed time integration procedure also features a time-step rejection and quarantine mechanisms, a modified Newton method with a predictor and dense output techniques to compute solution at off-step points.

Experiment on a three-beam adaptive array for EHF frequency-hopped signals using a fast algorithm, phase-D

NASA Astrophysics Data System (ADS)

Yen, J. L.; Kremer, P.; Amin, N.; Fung, J.

1989-05-01

The Department of National Defence (Canada) has been conducting studies into multi-beam adaptive arrays for extremely high frequency (EHF) frequency hopped signals. A three-beam 43 GHz adaptive antenna and a beam control processor is under development. An interactive software package for the operation of the array, capable of applying different control algorithms is being written. A maximum signal to jammer plus noise ratio (SJNR) was found to provide superior performance in preventing degradation of user signals in the presence of nearby jammers. A new fast algorithm using a modified conjugate gradient approach was found to be a very efficient way to implement anti-jamming arrays based on maximum SJNR criterion. The present study was intended to refine and simplify this algorithm and to implement the algorithm on an experimental array for real-time evaluation of anti-jamming performance. A three-beam adaptive array was used. A simulation package was used in the evaluation of multi-beam systems using more than three beams and different user-jammer scenarios. An attempt to further reduce the computation burden through continued analysis of maximum SJNR met with limited success. A method to acquire and track an incoming laser beam is proposed.

Experiment on a three-beam adaptive array for EHF frequency-hopped signals using a fast algorithm, phase E

NASA Astrophysics Data System (ADS)

Yen, J. L.; Kremer, P.; Fung, J.

1990-05-01

The Department of National Defence (Canada) has been conducting studies into multi-beam adaptive arrays for extremely high frequency (EHF) frequency hopped signals. A three-beam 43 GHz adaptive antenna and a beam control processor is under development. An interactive software package for the operation of the array, capable of applying different control algorithms is being written. A maximum signal to jammer plus noise ratio (SJNR) has been found to provide superior performance in preventing degradation of user signals in the presence of nearby jammers. A new fast algorithm using a modified conjugate gradient approach has been found to be a very efficient way to implement anti-jamming arrays based on maximum SJNR criterion. The present study was intended to refine and simplify this algorithm and to implement the algorithm on an experimental array for real-time evaluation of anti-jamming performance. A three-beam adaptive array was used. A simulation package was used in the evaluation of multi-beam systems using more than three beams and different user-jammer scenarios. An attempt to further reduce the computation burden through further analysis of maximum SJNR met with limited success. The investigation of a new angle detector for spatial tracking in heterodyne laser space communications was completed.

Artificial Metamorphosis: Evolutionary Design of Transforming, Soft-Bodied Robots.

PubMed

Joachimczak, Michał; Suzuki, Reiji; Arita, Takaya

2016-01-01

We show how the concept of metamorphosis, together with a biologically inspired model of multicellular development, can be used to evolve soft-bodied robots that are adapted to two very different tasks, such as being able to move in an aquatic and in a terrestrial environment. Each evolved solution defines two pairs of morphologies and controllers, together with a process of transforming one pair into the other. Animats develop from a single cell and grow through cellular divisions and deaths until they reach an initial larval form adapted to a first environment. To obtain the adult form adapted to a second environment, the larva undergoes metamorphosis, during which new cells are added or removed and its controller is modified. Importantly, our approach assumes nothing about what morphologies or methods of locomotion are preferred. Instead, it successfully searches the vast space of possible designs and comes up with complex, surprising, lifelike solutions that are reminiscent of amphibian metamorphosis. We analyze obtained solutions and investigate whether the morphological changes during metamorphosis are indeed adaptive. We then compare the effectiveness of three different types of selective pressures used to evolve metamorphic individuals. Finally, we investigate potential advantages of using metamorphosis to automatically produce soft-bodied designs by comparing the performance of metamorphic individuals with their specialized counterparts and designs that are robust to both environments.

A bi-hemispheric neuronal network model of the cerebellum with spontaneous climbing fiber firing produces asymmetrical motor learning during robot control.

PubMed

Pinzon-Morales, Ruben-Dario; Hirata, Yutaka

2014-01-01

To acquire and maintain precise movement controls over a lifespan, changes in the physical and physiological characteristics of muscles must be compensated for adaptively. The cerebellum plays a crucial role in such adaptation. Changes in muscle characteristics are not always symmetrical. For example, it is unlikely that muscles that bend and straighten a joint will change to the same degree. Thus, different (i.e., asymmetrical) adaptation is required for bending and straightening motions. To date, little is known about the role of the cerebellum in asymmetrical adaptation. Here, we investigate the cerebellar mechanisms required for asymmetrical adaptation using a bi-hemispheric cerebellar neuronal network model (biCNN). The bi-hemispheric structure is inspired by the observation that lesioning one hemisphere reduces motor performance asymmetrically. The biCNN model was constructed to run in real-time and used to control an unstable two-wheeled balancing robot. The load of the robot and its environment were modified to create asymmetrical perturbations. Plasticity at parallel fiber-Purkinje cell synapses in the biCNN model was driven by error signal in the climbing fiber (cf) input. This cf input was configured to increase and decrease its firing rate from its spontaneous firing rate (approximately 1 Hz) with sensory errors in the preferred and non-preferred direction of each hemisphere, as demonstrated in the monkey cerebellum. Our results showed that asymmetrical conditions were successfully handled by the biCNN model, in contrast to a single hemisphere model or a classical non-adaptive proportional and derivative controller. Further, the spontaneous activity of the cf, while relatively small, was critical for balancing the contribution of each cerebellar hemisphere to the overall motor command sent to the robot. Eliminating the spontaneous activity compromised the asymmetrical learning capabilities of the biCNN model. Thus, we conclude that a bi-hemispheric structure and adequate spontaneous activity of cf inputs are critical for cerebellar asymmetrical motor learning.

A bi-hemispheric neuronal network model of the cerebellum with spontaneous climbing fiber firing produces asymmetrical motor learning during robot control

PubMed Central

Pinzon-Morales, Ruben-Dario; Hirata, Yutaka

2014-01-01

To acquire and maintain precise movement controls over a lifespan, changes in the physical and physiological characteristics of muscles must be compensated for adaptively. The cerebellum plays a crucial role in such adaptation. Changes in muscle characteristics are not always symmetrical. For example, it is unlikely that muscles that bend and straighten a joint will change to the same degree. Thus, different (i.e., asymmetrical) adaptation is required for bending and straightening motions. To date, little is known about the role of the cerebellum in asymmetrical adaptation. Here, we investigate the cerebellar mechanisms required for asymmetrical adaptation using a bi-hemispheric cerebellar neuronal network model (biCNN). The bi-hemispheric structure is inspired by the observation that lesioning one hemisphere reduces motor performance asymmetrically. The biCNN model was constructed to run in real-time and used to control an unstable two-wheeled balancing robot. The load of the robot and its environment were modified to create asymmetrical perturbations. Plasticity at parallel fiber-Purkinje cell synapses in the biCNN model was driven by error signal in the climbing fiber (cf) input. This cf input was configured to increase and decrease its firing rate from its spontaneous firing rate (approximately 1 Hz) with sensory errors in the preferred and non-preferred direction of each hemisphere, as demonstrated in the monkey cerebellum. Our results showed that asymmetrical conditions were successfully handled by the biCNN model, in contrast to a single hemisphere model or a classical non-adaptive proportional and derivative controller. Further, the spontaneous activity of the cf, while relatively small, was critical for balancing the contribution of each cerebellar hemisphere to the overall motor command sent to the robot. Eliminating the spontaneous activity compromised the asymmetrical learning capabilities of the biCNN model. Thus, we conclude that a bi-hemispheric structure and adequate spontaneous activity of cf inputs are critical for cerebellar asymmetrical motor learning. PMID:25414644

Center for Adaptive Optics | Search

Science.gov Websites

Center for Adaptive Optics A University of California Science and Technology Center home Search CfAO Google Search search: CfAO All of UCOLick.org Whole Web Search for recent Adaptive Optics news at GoogleNews! Last Modified: Sep 21, 2010 Center for Adaptive Optics | Search | The Center | Adaptive Optics

Gesteme-free context-aware adaptation of robot behavior in human-robot cooperation.

PubMed

Nessi, Federico; Beretta, Elisa; Gatti, Cecilia; Ferrigno, Giancarlo; De Momi, Elena

2016-11-01

Cooperative robotics is receiving greater acceptance because the typical advantages provided by manipulators are combined with an intuitive usage. In particular, hands-on robotics may benefit from the adaptation of the assistant behavior with respect to the activity currently performed by the user. A fast and reliable classification of human activities is required, as well as strategies to smoothly modify the control of the manipulator. In this scenario, gesteme-based motion classification is inadequate because it needs the observation of a wide signal percentage and the definition of a rich vocabulary. In this work, a system able to recognize the user's current activity without a vocabulary of gestemes, and to accordingly adapt the manipulator's dynamic behavior is presented. An underlying stochastic model fits variations in the user's guidance forces and the resulting trajectories of the manipulator's end-effector with a set of Gaussian distribution. The high-level switching between these distributions is captured with hidden Markov models. The dynamic of the KUKA light-weight robot, a torque-controlled manipulator, is modified with respect to the classified activity using sigmoidal-shaped functions. The presented system is validated over a pool of 12 näive users in a scenario that addresses surgical targeting tasks on soft tissue. The robot's assistance is adapted in order to obtain a stiff behavior during activities that require critical accuracy constraint, and higher compliance during wide movements. Both the ability to provide the correct classification at each moment (sample accuracy) and the capability of correctly identify the correct sequence of activity (sequence accuracy) were evaluated. The proposed classifier is fast and accurate in all the experiments conducted (80% sample accuracy after the observation of ∼450ms of signal). Moreover, the ability of recognize the correct sequence of activities, without unwanted transitions is guaranteed (sequence accuracy ∼90% when computed far away from user desired transitions). Finally, the proposed activity-based adaptation of the robot's dynamic does not lead to a not smooth behavior (high smoothness, i.e. normalized jerk score <0.01). The provided system is able to dynamic assist the operator during cooperation in the presented scenario. Copyright © 2016 Elsevier B.V. All rights reserved.

Ground-based telescope pointing and tracking optimization using a neural controller.

PubMed

Mancini, D; Brescia, M; Schipani, P

2003-01-01

Neural network models (NN) have emerged as important components for applications of adaptive control theories. Their basic generalization capability, based on acquired knowledge, together with execution rapidity and correlation ability between input stimula, are basic attributes to consider NN as an extremely powerful tool for on-line control of complex systems. By a control system point of view, not only accuracy and speed, but also, in some cases, a high level of adaptation capability is required in order to match all working phases of the whole system during its lifetime. This is particularly remarkable for a new generation ground-based telescope control system. Infact, strong changes in terms of system speed and instantaneous position error tolerance are necessary, especially in case of trajectory disturb induced by wind shake. The classical control scheme adopted in such a system is based on the proportional integral (PI) filter, already applied and implemented on a large amount of new generation telescopes, considered as a standard in this technological environment. In this paper we introduce the concept of a new approach, the neural variable structure proportional integral, (NVSPI), related to the implementation of a standard multi layer perceptron network in new generation ground-based Alt-Az telescope control systems. Its main purpose is to improve adaptive capability of the Variable structure proportional integral model, an already innovative control scheme recently introduced by authors [Proc SPIE (1997)], based on a modified version of classical PI control model, in terms of flexibility and accuracy of the dynamic response range also in presence of wind noise effects. The realization of a powerful well tested and validated telescope model simulation system allowed the possibility to directly compare performances of the two control schemes on simulated tracking trajectories, revealing extremely encouraging results in terms of NVSPI control robustness and reliability.

Vestibular-somatosensory convergence in head movement control during locomotion after long-duration space flight.

PubMed

Mulavara, A P; Ruttley, T; Cohen, H S; Peters, B T; Miller, C; Brady, R; Merkle, L; Bloomberg, J J

2012-01-01

Space flight causes astronauts to be exposed to adaptation in both the vestibular and body load-sensing somatosensory systems. The goal of these studies was to examine the contributions of vestibular and body load-sensing somatosensory influences on vestibular mediated head movement control during locomotion after long-duration space flight. Subjects walked on a motor driven treadmill while performing a gaze stabilization task. Data were collected from three independent subject groups that included bilateral labyrinthine deficient (LD) patients, normal subjects before and after 30 minutes of 40% bodyweight unloaded treadmill walking, and astronauts before and after long-duration space flight. Motion data from the head and trunk segments were used to calculate the amplitude of angular head pitch and trunk vertical translation movement while subjects performed a gaze stabilization task, to estimate the contributions of vestibular reflexive mechanisms in head pitch movements. Exposure to unloaded locomotion caused a significant increase in head pitch movements in normal subjects, whereas the head pitch movements of LD patients were significantly decreased. This is the first evidence of adaptation of vestibular mediated head movement responses to unloaded treadmill walking. Astronaut subjects showed a heterogeneous response of both increases and decreases in the amplitude of head pitch movement. We infer that body load-sensing somatosensory input centrally modulates vestibular input and can adaptively modify vestibularly mediated head-movement control during locomotion. Thus, space flight may cause central adaptation of the converging vestibular and body load-sensing somatosensory systems leading to alterations in head movement control.

Vestibular-Somatosensory Convergence in Head Movement Control During Locomotion after Long-Duration Space Flight

NASA Technical Reports Server (NTRS)

Mulavara, Ajitkumar; Ruttley, Tara; Cohen, Helen; Peters, Brian; Miller, Chris; Brady, Rachel; Merkle, Lauren; Bloomberg, Jacob

2010-01-01

Exposure to the microgravity conditions of space flight induces adaptive modification in the control of vestibular-mediated reflexive head movement during locomotion after space flight. Space flight causes astronauts to be exposed to somatosensory adaptation in both the vestibular and body load-sensing (BLS) systems. The goal of these studies was to examine the contributions of vestibular and BLS-mediated somatosensory influences on head movement control during locomotion after long-duration space flight. Subjects were asked to walk on a treadmill driven at 1.8 m/s while performing a visual acuity task. Data were collected using the same testing protocol from three independent subject groups; 1) normal subjects before and after exposure to 30 minutes of 40% bodyweight unloaded treadmill walking, 2) bilateral labyrinthine deficient (LD) patients and 3) astronauts who performed the protocol before and after long duration space flight. Motion data from head and trunk segmental motion data were obtained to calculate the angular head pitch (HP) movements during walking trials while subjects performed the visual task, to estimate the contributions of vestibular reflexive mechanisms in HP movements. Results showed that exposure to unloaded locomotion caused a significant increase in HP movements, whereas in the LD patients the HP movements were significantly decreased. Astronaut subjects results showed a heterogeneous response of both increases and decreases in the amplitude of HP movement. We infer that BLS-mediated somatosensory input centrally modulates vestibular input and can adaptively modify head-movement control during locomotion. Thus, space flight may cause a central adaptation mediated by the converging vestibular and body load-sensing somatosensory systems.

Cascaded neural networks for sequenced propagation estimation, multiuser detection, and adaptive radio resource control of third-generation wireless networks for multimedia services

NASA Astrophysics Data System (ADS)

Hortos, William S.

1999-03-01

A hybrid neural network approach is presented to estimate radio propagation characteristics and multiuser interference and to evaluate their combined impact on throughput, latency and information loss in third-generation (3G) wireless networks. The latter three performance parameters influence the quality of service (QoS) for multimedia services under consideration for 3G networks. These networks, based on a hierarchical architecture of overlaying macrocells on top of micro- and picocells, are planned to operate in mobile urban and indoor environments with service demands emanating from circuit-switched, packet-switched and satellite-based traffic sources. Candidate radio interfaces for these networks employ a form of wideband CDMA in 5-MHz and wider-bandwidth channels, with possible asynchronous operation of the mobile subscribers. The proposed neural network (NN) architecture allocates network resources to optimize QoS metrics. Parameters of the radio propagation channel are estimated, followed by control of an adaptive antenna array at the base station to minimize interference, and then joint multiuser detection is performed at the base station receiver. These adaptive processing stages are implemented as a sequence of NN techniques that provide their estimates as inputs to a final- stage Kohonen self-organizing feature map (SOFM). The SOFM optimizes the allocation of available network resources to satisfy QoS requirements for variable-rate voice, data and video services. As the first stage of the sequence, a modified feed-forward multilayer perceptron NN is trained on the pilot signals of the mobile subscribers to estimate the parameters of shadowing, multipath fading and delays on the uplinks. A recurrent NN (RNN) forms the second stage to control base stations' adaptive antenna arrays to minimize intra-cell interference. The third stage is based on a Hopfield NN (HNN), modified to detect multiple users on the uplink radio channels to mitigate multiaccess interference, control carrier-sense multiple-access (CSMA) protocols, and refine call handoff procedures. In the final stage, the Kohonen SOFM, operating in a hybrid continuous and discrete space, adaptively allocates the resources of antenna-based cell sectorization, activity monitoring, variable-rate coding, power control, handoff and caller admission to meet user demands for various multimedia services at minimum QoS levels. The performance of the NN cascade is evaluated through simulation of a candidate 3G wireless network using W-CDMA parameters in a small-cell environment. The simulated network consists of a representative number of cells. Mobile users with typical movement patterns are assumed. QoS requirements for different classes of multimedia services are considered. The proposed method is shown to provide relatively low probability of new call blocking and handoff dropping, while maintaining efficient use of the network's radio resources.

Multiple model self-tuning control for a class of nonlinear systems

NASA Astrophysics Data System (ADS)

Huang, Miao; Wang, Xin; Wang, Zhenlei

2015-10-01

This study develops a novel nonlinear multiple model self-tuning control method for a class of nonlinear discrete-time systems. An increment system model and a modified robust adaptive law are proposed to expand the application range, thus eliminating the assumption that either the nonlinear term of the nonlinear system or its differential term is global-bounded. The nonlinear self-tuning control method can address the situation wherein the nonlinear system is not subject to a globally uniformly asymptotically stable zero dynamics by incorporating the pole-placement scheme. A novel, nonlinear control structure based on this scheme is presented to improve control precision. Stability and convergence can be confirmed when the proposed multiple model self-tuning control method is applied. Furthermore, simulation results demonstrate the effectiveness of the proposed method.

Recent innovations in edible and/or biodegradable packaging materials.

PubMed

Guilbert, S; Cuq, B; Gontard, N

1997-01-01

Certain newly discovered characteristics of natural biopolymers should make them a choice material to be used for different types of wrappings and films. Edible and/or biodegradable packagings produced from agricultural origin macromolecules provide a supplementary and sometimes essential means to control physiological, microbiological, and physicochemical changes in food products. This is accomplished (i) by controlling mass transfers between food product and ambient atmosphere or between components in heterogeneous food product, and (iii) by modifying and controlling food surface conditions (pH, level of specific functional agents, slow release of flavour compounds), it should be stressed that the material characteristics (polysaccharide, protein, or lipid, plasticized or not, chemically modified or not, used alone or in combination) and the fabrication procedures (casting of a film-forming solution, thermoforming) must be adapted to each specific food product and usage condition (relative humidity, temperature). Some potential uses of these materials (e.g. wrapping of various fabricated foods; protection of fruits and vegetables by control of maturation; protection of meat and fish; control of internal moisture transfer in pizzas), which are hinged on film properties (e.g. organoleptic, mechanical, gas and solute barrier) are described with examples.

High throughput analysis of red wine and grape phenolics-adaptation and validation of methyl cellulose precipitable tannin assay and modified Somers color assay to a rapid 96 well plate format.

PubMed

Mercurio, Meagan D; Dambergs, Robert G; Herderich, Markus J; Smith, Paul A

2007-06-13

The methyl cellulose precipitable (MCP) tannin assay and a modified version of the Somers and Evans color assay were adapted to high-throughput (HTP) analysis. To improve efficiency of the MCP tannin assay, a miniaturized 1 mL format and a HTP format using 96 well plates were developed. The Somers color assay was modified to allow the standardization of pH and ethanol concentrations of wine samples in a simple one-step dilution with a buffer solution, thus removing inconsistencies between wine matrices prior to analysis and allowing for its adaptation to a HTP format. Validation studies showed that all new formats were efficient, and results were reproducible and analogous to the original formats.

Adaptation of EVIAVE methodology for monitoring and follow-up when evaluating the environmental impact of landfills

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

Arrieta, Gabriela, E-mail: tonina1903@hotmail.com; Requena, Ignacio, E-mail: requena@decsai.ugr.es; Toro, Javier, E-mail: jjtoroca@unal.edu.co

Treatment and final disposal of Municipal Solid Waste can have a significant role in the generation of negative environmental impacts. As a prevention strategy, such activities are subjected to the process of Environmental Impact Assessment (EIA). Still, the follow-up of Environmental Management Plans or mitigation measures is limited, for one due to a lack of methodological approaches. In searching for possibilities, the University of Granada (Spain) developed a diagnostic methodology named EVIAVE, which allows one to quantify, by means of indexes, the environmental impact of landfills in view of their location and the conditions of exploitation. EVIAVE is applicable withinmore » the legal framework of the European Union and can be adapted to the environmental and legal conditions of other countries. This study entails its adaptation in Colombia, for the follow-up and control of the EIA process for landfills. Modifications involved inclusion of the environmental elements flora and fauna, and the evaluation of the environmental descriptors in agreement with the concept of vulnerability. The application of the modified EVIAVE in Colombian landfills allowed us to identify the elements affected by the operating conditions and maintenance. It may be concluded that this methodology is viable and effective for the follow-up and environmental control of EIA processes for landfills, and to analyze the associated risks, as it takes into account related environmental threats and vulnerabilities. - Highlights: • A modified methodology is used to monitor and follow-up environmental impacts in landfills. • The improved methodology includes the Vulnerability of Flora and Fauna to evaluate environmental impact of landfills. • The methodology serves to identify and evaluate the sources of risk generated in the construction and siting of landfills. • Environmental vulnerability indicators improve effectiveness of the control and follow-up phases of landfill management. • The follow-up of environmental management plans may help diminish the implementation gap in Environmental Impact Assessment.« less

Adaptations of the vestibular system to short and long-term exposures to altered gravity

NASA Astrophysics Data System (ADS)

Bruce, L. L.

2003-10-01

Long-term space flight creates unique environmental conditions to which the vestibular system must adapt for optimal survival of a given organism. The development and maintenance of vestibular connections are controlled by environmental gravitational stimulation as well as genetically controlled molecular interactions. This paper describes the effects of hypergravity on axonal growth and dendritic morphology, respectively. Two aspects of this vestibular adaptation are examined: (1) How does long-term exposure to hypergravity affect the development of vestibular axons? (2) How does short-term exposure to extremely rapid changes in gravity, such as those that occur during shuttle launch and landing, affect dendrites of the vestibulocerebellar system? To study the effects of longterm exposures to altered gravity, embryonic rats that developed in hypergravity were compared to microgravity-exposed and control rats. Examination of the vestibular projections from epithelia devoted to linear and angular acceleration revealed that the terminal fields segregate differently in rat embryos that gestated in each of the gravitational environments.To study the effects of short-term exposures to altered gravity, mice were exposed briefly to strong vestibular stimuli and the vestibulocerebellum was examined for any resulting morphological changes. My data show that these stimuli cause intense vestibular excitation of cerebellar Purkinje cells, which induce up-regulation of clathrin-mediated endocytosis and other morphological changes that are comparable to those seen in long-term depression. This system provides a basis for studying how the vestibular environment can modify cerebellar function, allowing animals to adapt to new environments.

Adaptation of time line analysis program to single pilot instrument flight research

NASA Technical Reports Server (NTRS)

Hinton, D. A.; Shaughnessy, J. D.

1978-01-01

A data base was developed for SPIFR operation and the program was run. The outputs indicated that further work was necessary on the workload models. In particular, the workload model for the cognitive channel should be modified as the output workload appears to be too small. Included in the needed refinements are models to show the workload when in turbulence, when overshooting a radial or glideslope, and when copying air traffic control clearances.

A modified theoretical framework to assess implementation fidelity of adaptive public health interventions.

PubMed

Pérez, Dennis; Van der Stuyft, Patrick; Zabala, Maríadel Carmen; Castro, Marta; Lefèvre, Pierre

2016-07-08

One of the major debates in implementation research turns around fidelity and adaptation. Fidelity is the degree to which an intervention is implemented as intended by its developers. It is meant to ensure that the intervention maintains its intended effects. Adaptation is the process of implementers or users bringing changes to the original design of an intervention. Depending on the nature of the modifications brought, adaptation could either be potentially positive or could carry the risk of threatening the theoretical basis of the intervention, resulting in a negative effect on expected outcomes. Adaptive interventions are those for which adaptation is allowed or even encouraged. Classical fidelity dimensions and conceptual frameworks do not address the issue of how to adapt an intervention while still maintaining its effectiveness. We support the idea that fidelity and adaptation co-exist and that adaptations can impact either positively or negatively on the intervention's effectiveness. For adaptive interventions, research should answer the question how an adequate fidelity-adaptation balance can be reached. One way to address this issue is by looking systematically at the aspects of an intervention that are being adapted. We conducted fidelity research on the implementation of an empowerment strategy for dengue prevention in Cuba. In view of the adaptive nature of the strategy, we anticipated that the classical fidelity dimensions would be of limited use for assessing adaptations. The typology we used in the assessment-implemented, not-implemented, modified, or added components of the strategy-also had limitations. It did not allow us to answer the question which of the modifications introduced in the strategy contributed to or distracted from outcomes. We confronted our empirical research with existing literature on fidelity, and as a result, considered that the framework for implementation fidelity proposed by Carroll et al. in 2007 could potentially meet our concerns. We propose modifications to the framework to assess both fidelity and adaptation. The modified Carroll et al.'s framework we propose may permit a comprehensive assessment of the implementation fidelity-adaptation balance required when implementing adaptive interventions, but more empirical research is needed to validate it.

Loss of Action via Neurotensin-Leptin Receptor Neurons Disrupts Leptin and Ghrelin-Mediated Control of Energy Balance.

PubMed

Brown, Juliette A; Bugescu, Raluca; Mayer, Thomas A; Gata-Garcia, Adriana; Kurt, Gizem; Woodworth, Hillary L; Leinninger, Gina M

2017-05-01

The hormones ghrelin and leptin act via the lateral hypothalamic area (LHA) to modify energy balance, but the underlying neural mechanisms remain unclear. We investigated how leptin and ghrelin engage LHA neurons to modify energy balance behaviors and whether there is any crosstalk between leptin and ghrelin-responsive circuits. We demonstrate that ghrelin activates LHA neurons expressing hypocretin/orexin (OX) to increase food intake. Leptin mediates anorectic actions via separate neurons expressing the long form of the leptin receptor (LepRb), many of which coexpress the neuropeptide neurotensin (Nts); we refer to these as NtsLepRb neurons. Because NtsLepRb neurons inhibit OX neurons, we hypothesized that disruption of the NtsLepRb neuronal circuit would impair both NtsLepRb and OX neurons from responding to their respective hormonal cues, thus compromising adaptive energy balance. Indeed, mice with developmental deletion of LepRb specifically from NtsLepRb neurons exhibit blunted adaptive responses to leptin and ghrelin that discoordinate the mesolimbic dopamine system and ingestive and locomotor behaviors, leading to weight gain. Collectively, these data reveal a crucial role for LepRb in the proper formation of LHA circuits, and that NtsLepRb neurons are important neuronal hubs within the LHA for hormone-mediated control of ingestive and locomotor behaviors. Copyright © 2017 Endocrine Society.

Intelligent control of an IPMC actuated manipulator using emotional learning-based controller

NASA Astrophysics Data System (ADS)

Shariati, Azadeh; Meghdari, Ali; Shariati, Parham

2008-08-01

In this research an intelligent emotional learning controller, Takagi- Sugeno- Kang (TSK) is applied to govern the dynamics of a novel Ionic-Polymer Metal Composite (IPMC) actuated manipulator. Ionic-Polymer Metal Composites are active actuators that show very large deformation in existence of low applied voltage. In this research, a new IPMC actuator is considered and applied to a 2-dof miniature manipulator. This manipulator is designed for miniature tasks. The control system consists of a set of neurofuzzy controller whose parameters are adapted according to the emotional learning rules, and a critic with task to assess the present situation resulted from the applied control action in terms of satisfactory achievement of the control goals and provides the emotional signal (the stress). The controller modifies its characteristics so that the critic's stress decreased.

Computer aided design of digital controller for radial active magnetic bearings

NASA Technical Reports Server (NTRS)

Cai, Zhong; Shen, Zupei; Zhang, Zuming; Zhao, Hongbin

1992-01-01

A five degree of freedom Active Magnetic Bearing (AMB) system is developed which is controlled by digital controllers. The model of the radial AMB system is linearized and the state equation is derived. Based on the state variables feedback theory, digital controllers are designed. The performance of the controllers are evaluated according to experimental results. The Computer Aided Design (CAD) method is used to design controllers for magnetic bearings. The controllers are implemented with a digital signal processing (DSP) system. The control algorithms are realized with real-time programs. It is very easy to change the controller by changing or modifying the programs. In order to identify the dynamic parameters of the controlled magnetic system, a special experiment was carried out. Also, the online Recursive Least Squares (RLS) parameter identification method is studied. It can be realized with the digital controllers. Online parameter identification is essential for the realization of an adaptive controller.

A modified adjoint-based grid adaptation and error correction method for unstructured grid

NASA Astrophysics Data System (ADS)

Cui, Pengcheng; Li, Bin; Tang, Jing; Chen, Jiangtao; Deng, Youqi

2018-05-01

Grid adaptation is an important strategy to improve the accuracy of output functions (e.g. drag, lift, etc.) in computational fluid dynamics (CFD) analysis and design applications. This paper presents a modified robust grid adaptation and error correction method for reducing simulation errors in integral outputs. The procedure is based on discrete adjoint optimization theory in which the estimated global error of output functions can be directly related to the local residual error. According to this relationship, local residual error contribution can be used as an indicator in a grid adaptation strategy designed to generate refined grids for accurately estimating the output functions. This grid adaptation and error correction method is applied to subsonic and supersonic simulations around three-dimensional configurations. Numerical results demonstrate that the sensitive grids to output functions are detected and refined after grid adaptation, and the accuracy of output functions is obviously improved after error correction. The proposed grid adaptation and error correction method is shown to compare very favorably in terms of output accuracy and computational efficiency relative to the traditional featured-based grid adaptation.

Turkish version of the modified Constant-Murley score and standardized test protocol: reliability and validity.

PubMed

Çelik, Derya

2016-01-01

The Constant-Murley score (CMS) is widely used to evaluate disabilities associated with shoulder injuries, but it has been criticized for relying on imprecise terminology and a lack of standardized methodology. A modified guideline, therefore, was published in 2008 with several recommendations. This new version has not yet been translated or culturally adapted for Turkish-speaking populations. The purpose of this study was to translate and cross-culturally adapt the modified CMS and its test protocol, as well as define and measure its reliability and validity. The modified CMS was translated into Turkish, consistent with published methodological guidelines. The measurement properties of the Turkish version of the modified CMS were tested in 30 patients (12 males, 18 females; mean age: 59.5±13.5 years) with a variety of shoulder pathologies. Intraclass correlation coefficients (ICC) were used to estimate test-retest reliability. Construct validity was analyzed with the Turkish version of the American Shoulder and Elbow Surgeons (ASES) Standardized Shoulder Assessment Form and Short-Form Health Survey (SF-12). No difficulties were found in the translation process. The Turkish version of the modified CMS showed excellent test-retest reliability (ICC=0.86). The correlation coefficients between the Turkish version of the modified CMS and the ASES, SF-12-physical component score, and SF-12 mental component scores were found to be 0.48, 0.35, and 0.05, respectively. No floor or ceiling effects were found. The translation and cultural adaptation of the modified CMS and its standardized test protocol into Turkish were successful. The Turkish version of the modified CMS has sufficient reliability and validity to measure a variety of shoulder disorders for Turkish-speaking individuals.

Prediction of flood abnormalities for improved public safety using a modified adaptive neuro-fuzzy inference system.

PubMed

Aqil, M; Kita, I; Yano, A; Nishiyama, S

2006-01-01

It is widely accepted that an efficient flood alarm system may significantly improve public safety and mitigate economical damages caused by inundations. In this paper, a modified adaptive neuro-fuzzy system is proposed to modify the traditional neuro-fuzzy model. This new method employs a rule-correction based algorithm to replace the error back propagation algorithm that is employed by the traditional neuro-fuzzy method in backward pass calculation. The final value obtained during the backward pass calculation using the rule-correction algorithm is then considered as a mapping function of the learning mechanism of the modified neuro-fuzzy system. Effectiveness of the proposed identification technique is demonstrated through a simulation study on the flood series of the Citarum River in Indonesia. The first four-year data (1987 to 1990) was used for model training/calibration, while the other remaining data (1991 to 2002) was used for testing the model. The number of antecedent flows that should be included in the input variables was determined by two statistical methods, i.e. autocorrelation and partial autocorrelation between the variables. Performance accuracy of the model was evaluated in terms of two statistical indices, i.e. mean average percentage error and root mean square error. The algorithm was developed in a decision support system environment in order to enable users to process the data. The decision support system is found to be useful due to its interactive nature, flexibility in approach, and evolving graphical features, and can be adopted for any similar situation to predict the streamflow. The main data processing includes gauging station selection, input generation, lead-time selection/generation, and length of prediction. This program enables users to process the flood data, to train/test the model using various input options, and to visualize results. The program code consists of a set of files, which can be modified as well to match other purposes. This program may also serve as a tool for real-time flood monitoring and process control. The results indicate that the modified neuro-fuzzy model applied to the flood prediction seems to have reached encouraging results for the river basin under examination. The comparison of the modified neuro-fuzzy predictions with the observed data was satisfactory, where the error resulted from the testing period was varied between 2.632% and 5.560%. Thus, this program may also serve as a tool for real-time flood monitoring and process control.

A Robust Design Methodology for Optimal Microscale Secondary Flow Control in Compact Inlet Diffusers

NASA Technical Reports Server (NTRS)

Anderson, Bernhard H.; Keller, Dennis J.

2001-01-01

It is the purpose of this study to develop an economical Robust design methodology for microscale secondary flow control in compact inlet diffusers. To illustrate the potential of economical Robust Design methodology, two different mission strategies were considered for the subject inlet, namely Maximum Performance and Maximum HCF Life Expectancy. The Maximum Performance mission maximized total pressure recovery while the Maximum HCF Life Expectancy mission minimized the mean of the first five Fourier harmonic amplitudes, i.e., 'collectively' reduced all the harmonic 1/2 amplitudes of engine face distortion. Each of the mission strategies was subject to a low engine face distortion constraint, i.e., DC60<0.10, which is a level acceptable for commercial engines. For each of these missions strategies, an 'Optimal Robust' (open loop control) and an 'Optimal Adaptive' (closed loop control) installation was designed over a twenty degree angle-of-incidence range. The Optimal Robust installation used economical Robust Design methodology to arrive at a single design which operated over the entire angle-of-incident range (open loop control). The Optimal Adaptive installation optimized all the design parameters at each angle-of-incidence. Thus, the Optimal Adaptive installation would require a closed loop control system to sense a proper signal for each effector and modify that effector device, whether mechanical or fluidic, for optimal inlet performance. In general, the performance differences between the Optimal Adaptive and Optimal Robust installation designs were found to be marginal. This suggests, however, that Optimal Robust open loop installation designs can be very competitive with Optimal Adaptive close loop designs. Secondary flow control in inlets is inherently robust, provided it is optimally designed. Therefore, the new methodology presented in this paper, combined array 'Lower Order' approach to Robust DOE, offers the aerodynamicist a very viable and economical way of exploring the concept of Robust inlet design, where the mission variables are brought directly into the inlet design process and insensitivity or robustness to the mission variables becomes a design objective.

Adapting the academic motivation scale for use in pre-tertiary mathematics classrooms

NASA Astrophysics Data System (ADS)

Lim, Siew Yee; Chapman, Elaine

2015-09-01

The Academic Motivation Scale ( ams) is a comprehensive and widely used instrument for assessing motivation based on the self-determination theory. Currently, no such comprehensive instrument exists to assess the different domains of motivation (stipulated by the self-determination theory) in mathematics education at the pre-tertiary level (grades 11 and 12) in Asia. This study adapted the ams for this use and assessed the properties of the adapted instrument with 1610 students from Singapore. Exploratory and confirmatory factor analyses indicated a five-factor structure for the modified instrument (the three original ams intrinsic subscales collapsed into a single factor). Additionally, the modified instrument exhibited good internal consistency (mean α = .88), and satisfactory test-retest reliability over a 1-month interval (mean r xx = .73). The validity of the modified ams was further demonstrated through correlational analyses among scores on its subscales, and with scores on other instruments measuring mathematics attitudes, anxiety and achievement.

Generalized sidelobe canceller beamforming method for ultrasound imaging.

PubMed

Wang, Ping; Li, Na; Luo, Han-Wu; Zhu, Yong-Kun; Cui, Shi-Gang

2017-03-01

A modified generalized sidelobe canceller (IGSC) algorithm is proposed to enhance the resolution and robustness against the noise of the traditional generalized sidelobe canceller (GSC) and coherence factor combined method (GSC-CF). In the GSC algorithm, weighting vector is divided into adaptive and non-adaptive parts, while the non-adaptive part does not block all the desired signal. A modified steer vector of the IGSC algorithm is generated by the projection of the non-adaptive vector on the signal space constructed by the covariance matrix of received data. The blocking matrix is generated based on the orthogonal complementary space of the modified steer vector and the weighting vector is updated subsequently. The performance of IGSC was investigated by simulations and experiments. Through simulations, IGSC outperformed GSC-CF in terms of spatial resolution by 0.1 mm regardless there is noise or not, as well as the contrast ratio respect. The proposed IGSC can be further improved by combining with CF. The experimental results also validated the effectiveness of the proposed algorithm with dataset provided by the University of Michigan.

Role of α-synuclein in inducing innate and adaptive immunity in Parkinson disease

PubMed Central

Allen Reish, Heather E.; Standaert, David G.

2015-01-01

Alpha-synuclein (α-syn) is central to the pathogenesis of Parkinson disease (PD). Gene duplications, triplications and point mutations in SNCA1, the gene encoding α-syn, cause autosomal dominant forms of PD. Aggregated and post-translationally modified forms of α-syn are present in Lewy bodies and Lewy neurites in both sporadic and familial PD, and recent work has emphasized the prion-like ability of aggregated α-syn to produce spreading pathology. Accumulation of abnormal forms of α-syn is a trigger for PD, but recent evidence suggests that much of the downstream neurodegeneration may result from inflammatory responses. Components of both the innate and adaptive immune systems are activated in PD, and influencing interactions between innate and adaptive immune components has been shown to modify the pathological process in animal models of PD. Understanding the relationship between α-syn and subsequent inflammation may reveal novel targets for neuroprotective interventions. In this review, we examine the role of α-syn and modified forms of this protein in the initiation of innate and adaptive immune responses. PMID:25588354

Optical fiber pressure sensors for adaptive wings

NASA Astrophysics Data System (ADS)

Duncan, Paul G.; Jones, Mark E.; Shinpaugh, Kevin A.; Poland, Stephen H.; Murphy, Kent A.; Claus, Richard O.

1997-06-01

Optical fiber pressure sensors have been developed for use on a structurally-adaptive `smart wing'; further details of the design, fabrication and testing of the smart wing concept are presented in companion papers. This paper describes the design, construction, and performance of the pressure sensor and a combined optical and electronic signal processing system implemented to permit the measurement of a large number of sensors distributed over the control surfaces of a wing. Optical fiber pressure sensors were implemented due to anticipated large electromagnetic interference signals within the operational environment. The sensors utilized the principle of the extrinsic Fabry-Perot interferometer (EFPI) already developed for the measurement of strain and temperature. Here, the cavity is created inside a micromachined hollow-core tube with a silicon diaphragm at one end. The operation of the sensor is similar to that of the EFPI strain gage also discussed in several papers at this conference. The limitations placed upon the performance of the digital signal processing system were determined by the required pressure range of the sensors and the cycle time of the control system used to adaptively modify the shape of the wing. Sensor calibration and the results of testing performed are detailed.

Solving systems of linear equations by GPU-based matrix factorization in a Science Ground Segment

NASA Astrophysics Data System (ADS)

Legendre, Maxime; Schmidt, Albrecht; Moussaoui, Saïd; Lammers, Uwe

2013-11-01

Recently, Graphics Cards have been used to offload scientific computations from traditional CPUs for greater efficiency. This paper investigates the adaptation of a real-world linear system solver, which plays a central role in the data processing of the Science Ground Segment of ESA's astrometric Gaia mission. The paper quantifies the resource trade-offs between traditional CPU implementations and modern CUDA based GPU implementations. It also analyses the impact on the pipeline architecture and system development. The investigation starts from both a selected baseline algorithm with a reference implementation and a traditional linear system solver and then explores various modifications to control flow and data layout to achieve higher resource efficiency. It turns out that with the current state of the art, the modifications impact non-technical system attributes. For example, the control flow of the original modified Cholesky transform is modified so that locality of the code and verifiability deteriorate. The maintainability of the system is affected as well. On the system level, users will have to deal with more complex configuration control and testing procedures.

Control of locomotor stability in stabilizing and destabilizing environments.

PubMed

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

2017-06-01

To develop effective interventions targeting locomotor stability, it is crucial to understand how people control and modify gait in response to changes in stabilization requirements. Our purpose was to examine how individuals with and without incomplete spinal cord injury (iSCI) control lateral stability in haptic walking environments that increase or decrease stabilization demands. We hypothesized that people would adapt to walking in a predictable, stabilizing viscous force field and unpredictable destabilizing force field by increasing and decreasing feedforward control of lateral stability, respectively. Adaptations in feedforward control were measured using after-effects when fields were removed. Both groups significantly (p<0.05) decreased step width in the stabilizing field. When the stabilizing field was removed, narrower steps persisted in both groups and subjects with iSCI significantly increased movement variability (p<0.05). The after-effect of walking in the stabilizing field was a suppression of ongoing general stabilization mechanisms. In the destabilizing field, subjects with iSCI took faster steps and increased lateral margins of stability (p<0.05). Step frequency increases persisted when the destabilizing field was removed (p<0.05), suggesting that subjects with iSCI made feedforward adaptions to increase control of lateral stability. In contrast, in the destabilizing field, non-impaired subjects increased movement variability (p<0.05) and did not change step width, step frequency, or lateral margin of stability (p>0.05). When the destabilizing field was removed, increases in movement variability persisted (p<0.05), suggesting that non-impaired subjects made feedforward decreases in resistance to perturbations. Published by Elsevier B.V.

Adhesive Sociocultural Adaptation of Korean Immigrants in the U.S.: An Alternative Strategy of Minority Adaptation.

ERIC Educational Resources Information Center

Hurh, Won Moo; Kim, Kwang Chung

1984-01-01

"Adhesive adaptation" occurs when aspects of a new culture and social relations with members of the host society are added on to immigrants' traditional culture and social networks, without replacing or modifying any significant part of the old. Interviews with 615 Korean immigrants empirically confirmed this adaptation model. (Author/KH)

Method for removing tilt control in adaptive optics systems

DOEpatents

Salmon, J.T.

1998-04-28

A new adaptive optics system and method of operation are disclosed, whereby the method removes tilt control, and includes the steps of using a steering mirror to steer a wavefront in the desired direction, for aiming an impinging aberrated light beam in the direction of a deformable mirror. The deformable mirror has its surface deformed selectively by means of a plurality of actuators, and compensates, at least partially, for existing aberrations in the light beam. The light beam is split into an output beam and a sample beam, and the sample beam is sampled using a wavefront sensor. The sampled signals are converted into corresponding electrical signals for driving a controller, which, in turn, drives the deformable mirror in a feedback loop in response to the sampled signals, for compensating for aberrations in the wavefront. To this purpose, a displacement error (gradient) of the wavefront is measured, and adjusted by a modified gain matrix, which satisfies the following equation: G{prime} = (I{minus}X(X{sup T} X){sup {minus}1}X{sup T})G(I{minus}A). 3 figs.

Experimental approaches to well controlled studies of thin-film nucleation and growth.

NASA Technical Reports Server (NTRS)

Poppa, H.; Moorhead, R. D.; Heinemann, K.

1972-01-01

Particular features and the performance of two experimental systems are described for quantitative studies of thin-film nucleation and growth processes including epitaxial depositions. System I consists of a modified LEED-Auger instrument combined with high-resolution electron microscopy. System II is a UHV electron microscope adapted for in-situ deposition studies. The two systems complement each other ideally, and the combined use of both can result in a comprehensive investigation of vapor deposition processes not obtainable with any other known method.

Adaptive estimation of nonlinear parameters of a nonholonomic spherical robot using a modified fuzzy-based speed gradient algorithm

NASA Astrophysics Data System (ADS)

Roozegar, Mehdi; Mahjoob, Mohammad J.; Ayati, Moosa

2017-05-01

This paper deals with adaptive estimation of the unknown parameters and states of a pendulum-driven spherical robot (PDSR), which is a nonlinear in parameters (NLP) chaotic system with parametric uncertainties. Firstly, the mathematical model of the robot is deduced by applying the Newton-Euler methodology for a system of rigid bodies. Then, based on the speed gradient (SG) algorithm, the states and unknown parameters of the robot are estimated online for different step length gains and initial conditions. The estimated parameters are updated adaptively according to the error between estimated and true state values. Since the errors of the estimated states and parameters as well as the convergence rates depend significantly on the value of step length gain, this gain should be chosen optimally. Hence, a heuristic fuzzy logic controller is employed to adjust the gain adaptively. Simulation results indicate that the proposed approach is highly encouraging for identification of this NLP chaotic system even if the initial conditions change and the uncertainties increase; therefore, it is reliable to be implemented on a real robot.

Adaptive optics compensation of orbital angular momentum beams with a modified Gerchberg-Saxton-based phase retrieval algorithm

NASA Astrophysics Data System (ADS)

Chang, Huan; Yin, Xiao-li; Cui, Xiao-zhou; Zhang, Zhi-chao; Ma, Jian-xin; Wu, Guo-hua; Zhang, Li-jia; Xin, Xiang-jun

2017-12-01

Practical orbital angular momentum (OAM)-based free-space optical (FSO) communications commonly experience serious performance degradation and crosstalk due to atmospheric turbulence. In this paper, we propose a wave-front sensorless adaptive optics (WSAO) system with a modified Gerchberg-Saxton (GS)-based phase retrieval algorithm to correct distorted OAM beams. We use the spatial phase perturbation (SPP) GS algorithm with a distorted probe Gaussian beam as the only input. The principle and parameter selections of the algorithm are analyzed, and the performance of the algorithm is discussed. The simulation results show that the proposed adaptive optics (AO) system can significantly compensate for distorted OAM beams in single-channel or multiplexed OAM systems, which provides new insights into adaptive correction systems using OAM beams.

Effectiveness of adaptive pretend play on affective expression and imagination of children with cerebral palsy.

PubMed

Hsieh, Hsieh-Chun

2012-01-01

Children with cerebral palsy (CP) have difficulty participating in role-pretending activities. The concept of adaptive play makes play accessible by modifying play materials for different needs or treatment goals for children with CP. This study examines the affective expressions and imagination in children with CP as a function of ordinary versus adaptive pretend play. The Affect in Play Scale-Brief Rating measured the affective expression and imagination for 29 children with CP and 29 typically developing children (mean age=7.34 years). Two groups of children were observed while playing with a standard set of ordinary toys for ten times and with a standard procedure of adaptive pretend play for ten times. The results show significantly different affective expressions and imagination between the two groups. Typically developing children displayed much more affective expression and imagination. However, a more positive influence of affective expression and imagination occurred in children with CP than in typically developing children. In repeated measures analysis, the frequency of positive affective expression and imagination of children with CP was higher when pretending with adaptive toys. Adaptive pretend play can promote more role-pretending behaviors and a sense of environmental control during the manipulating process for children with CP. Copyright © 2012 Elsevier Ltd. All rights reserved.

Preadaptation to the stimulus rearrangement of weightlessness: Preliminary studies and concepts for trainer designs

NASA Technical Reports Server (NTRS)

Parker, D. E.; Reschke, M. F.

1988-01-01

An effort to develop preflight adaptation training (PAT) apparatus and procedures to adapt astronauts to the stimulus rearrangement of weightless spaceflight is being pursued. Based on the otolith tilt-translation reinterpretation model of sensory adaptation to weightlessness, two prototype preflight adaptation trainers (PAT) have been developed. These trainers couple pitch movement of the subject with translation of the visual surround. Subjects were exposed to this stimulus rearrangement for periods of 30 m. The hypothesis is that exposure to the rearrangement would attenuate vertical eye movements was supported by two experiments using the Miami University Seesaw (MUS) PAT prototype. The Dynamic Environment Simulator (DES) prototype failed to support this hypothesis; this result is attributed to a pecularity of the DES apparatus. A final experiment demonstrated that changes in vertical eye movements were not a consequence of fixation on an external target during exposure to a control condition. Together these experiments support the view that preflight adaptation training can alter eye movements in a manner consistent with adaptation to weightlessness. Following these initial studies, concepts for development of operational preflight trainers were proposed. The trainers are intended to: demonstrate the stimulus rearrangement of weightlessness; allow astronauts to train in altered sensory environment; modify sensory motor reflexes; and reduce/eliminate space motion sickness symptoms.

50 CFR 217.178 - Renewal of Letters of Authorization and adaptive management.

Code of Federal Regulations, 2013 CFR

2013-10-01

... appropriate pursuant to the adaptive management component of these regulations, provided that: (1) NMFS is... pursuant to the adaptive management component of these regulations indicates that a substantial... modify or augment the existing mitigation or monitoring measures (after consulting with Neptune regarding...

50 CFR 217.178 - Renewal of Letters of Authorization and adaptive management.

Code of Federal Regulations, 2014 CFR

2014-10-01

... appropriate pursuant to the adaptive management component of these regulations, provided that: (1) NMFS is... pursuant to the adaptive management component of these regulations indicates that a substantial... modify or augment the existing mitigation or monitoring measures (after consulting with Neptune regarding...

50 CFR 217.178 - Renewal of Letters of Authorization and adaptive management.

Code of Federal Regulations, 2012 CFR

2012-10-01

... appropriate pursuant to the adaptive management component of these regulations, provided that: (1) NMFS is... pursuant to the adaptive management component of these regulations indicates that a substantial... modify or augment the existing mitigation or monitoring measures (after consulting with Neptune regarding...

50 CFR 218.241 - Adaptive management.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Low Frequency Active (SURTASS LFA) Sonar § 218.241 Adaptive management. NMFS may modify (including...) Results from the Navy's monitoring from the previous year's operation of SURTASS LFA sonar. (b) Compiled...

50 CFR 218.241 - Adaptive management.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Low Frequency Active (SURTASS LFA) Sonar § 218.241 Adaptive management. NMFS may modify (including...) Results from the Navy's monitoring from the previous year's operation of SURTASS LFA sonar. (b) Compiled...

50 CFR 218.241 - Adaptive management.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Low Frequency Active (SURTASS LFA) Sonar § 218.241 Adaptive management. NMFS may modify (including...) Results from the Navy's monitoring from the previous year's operation of SURTASS LFA sonar. (b) Compiled...

Effects of dynamic-demand-control appliances on the power grid frequency.

PubMed

Tchuisseu, E B Tchawou; Gomila, D; Brunner, D; Colet, P

2017-08-01

Power grid frequency control is a demanding task requiring expensive idle power plants to adapt the supply to the fluctuating demand. An alternative approach is controlling the demand side in such a way that certain appliances modify their operation to adapt to the power availability. This is especially important to achieve a high penetration of renewable energy sources. A number of methods to manage the demand side have been proposed. In this work we focus on dynamic demand control (DDC), where smart appliances can delay their switchings depending on the frequency of the system. We introduce a simple model to study the effects of DDC on the frequency of the power grid. The model includes the power plant equations, a stochastic model for the demand that reproduces, adjusting a single parameter, the statistical properties of frequency fluctuations measured experimentally, and a generic DDC protocol. We find that DDC can reduce small and medium-size fluctuations but it can also increase the probability of observing large frequency peaks due to the necessity of recovering pending task. We also conclude that a deployment of DDC around 30-40% already allows a significant reduction of the fluctuations while keeping the number of pending tasks low.

Effects of dynamic-demand-control appliances on the power grid frequency

NASA Astrophysics Data System (ADS)

Tchuisseu, E. B. Tchawou; Gomila, D.; Brunner, D.; Colet, P.

2017-08-01

Power grid frequency control is a demanding task requiring expensive idle power plants to adapt the supply to the fluctuating demand. An alternative approach is controlling the demand side in such a way that certain appliances modify their operation to adapt to the power availability. This is especially important to achieve a high penetration of renewable energy sources. A number of methods to manage the demand side have been proposed. In this work we focus on dynamic demand control (DDC), where smart appliances can delay their switchings depending on the frequency of the system. We introduce a simple model to study the effects of DDC on the frequency of the power grid. The model includes the power plant equations, a stochastic model for the demand that reproduces, adjusting a single parameter, the statistical properties of frequency fluctuations measured experimentally, and a generic DDC protocol. We find that DDC can reduce small and medium-size fluctuations but it can also increase the probability of observing large frequency peaks due to the necessity of recovering pending task. We also conclude that a deployment of DDC around 30-40% already allows a significant reduction of the fluctuations while keeping the number of pending tasks low.

3D numerical simulations of oblique droplet impact onto a deep liquid pool

NASA Astrophysics Data System (ADS)

Gelderblom, Hanneke; Reijers, Sten A.; Gielen, Marise; Sleutel, Pascal; Lohse, Detlef; Xie, Zhihua; Pain, Christopher C.; Matar, Omar K.

2017-11-01

We study the fluid dynamics of three-dimensional oblique droplet impact, which results in phenomena that include splashing and cavity formation. An adaptive, unstructured mesh modelling framework is employed here, which can modify and adapt unstructured meshes to better represent the underlying physics of droplet dynamics, and reduce computational effort without sacrificing accuracy. The numerical framework consists of a mixed control-volume and finite-element formulation, a volume-of-fluid-type method for the interface-capturing based on a compressive control-volume advection method. The framework also features second-order finite-element methods, and a force-balanced algorithm for the surface tension implementation, minimising the spurious velocities often found in many simulations involving capillary-driven flows. The numerical results generated using this framework are compared with high-speed images of the interfacial shapes of the deformed droplet, and the cavity formed upon impact, yielding good agreement. EPSRC, UK, MEMPHIS program Grant (EP/K003976/1), RAEng Research Chair (OKM).

Meal Detection in Patients With Type 1 Diabetes: A New Module for the Multivariable Adaptive Artificial Pancreas Control System.

PubMed

Turksoy, Kamuran; Samadi, Sediqeh; Feng, Jianyuan; Littlejohn, Elizabeth; Quinn, Laurie; Cinar, Ali

2016-01-01

A novel meal-detection algorithm is developed based on continuous glucose measurements. Bergman's minimal model is modified and used in an unscented Kalman filter for state estimations. The estimated rate of appearance of glucose is used for meal detection. Data from nine subjects are used to assess the performance of the algorithm. The results indicate that the proposed algorithm works successfully with high accuracy. The average change in glucose levels between the meals and the detection points is 16(±9.42) [mg/dl] for 61 successfully detected meals and snacks. The algorithm is developed as a new module of an integrated multivariable adaptive artificial pancreas control system. Meal detection with the proposed method is used to administer insulin boluses and prevent most of postprandial hyperglycemia without any manual meal announcements. A novel meal bolus calculation method is proposed and tested with the UVA/Padova simulator. The results indicate significant reduction in hyperglycemia.

Composite anion-exchangers modified with nanoparticles of hydrated oxides of multivalent metals

NASA Astrophysics Data System (ADS)

Maltseva, T. V.; Kolomiets, E. O.; Dzyazko, Yu. S.; Scherbakov, S.

2018-02-01

Organic-inorganic composite ion-exchangers based on anion exchange resins have been obtained. Particles of one-component and two-component modifier were embedded using the approach, which allows us to realize purposeful control of a size of the embedded particles. The approach is based on Ostwald-Freundlich equation, which was adapted to deposition in ion exchange matrix. The equation was obtained experimentally. Hydrated oxides of zirconium and iron were applied to modification, concentration of the reagents were varied. The embedded particles accelerate sorption, the rate of which is fitted by the model equation of chemical reactions of pseudo-second order. When sorption of arsenate ions from very diluted solution (50 µg dm-3) occurs, the composites show higher distribution coefficients comparing with the pristine resin.

Fourth Graders Make Inventions Using SCAMPER and Animal Adaptation Ideas

ERIC Educational Resources Information Center

Hussain, Mahjabeen; Carignan, Anastasia

2016-01-01

This study explores to what extent the SCAMPER (Substitute, Combine, Adapt, Modify, Put to another use, Eliminate, and Rearrange) technique combined with animal adaptation ideas learned through form and function analogy activities can help fourth graders generate creative ideas while augmenting their inventiveness. The sample consisted of 24…

Locomotor adaptability in persons with unilateral transtibial amputation.

PubMed

Darter, Benjamin J; Bastian, Amy J; Wolf, Erik J; Husson, Elizabeth M; Labrecque, Bethany A; Hendershot, Brad D

2017-01-01

Locomotor adaptation enables walkers to modify strategies when faced with challenging walking conditions. While a variety of neurological injuries can impair locomotor adaptability, the effect of a lower extremity amputation on adaptability is poorly understood. Determine if locomotor adaptability is impaired in persons with unilateral transtibial amputation (TTA). The locomotor adaptability of 10 persons with a TTA and 8 persons without an amputation was tested while walking on a split-belt treadmill with the parallel belts running at the same (tied) or different (split) speeds. In the split condition, participants walked for 15 minutes with the respective belts moving at 0.5 m/s and 1.5 m/s. Temporal spatial symmetry measures were used to evaluate reactive accommodations to the perturbation, and the adaptive/de-adaptive response. Persons with TTA and the reference group of persons without amputation both demonstrated highly symmetric walking at baseline. During the split adaptation and tied post-adaptation walking both groups responded with the expected reactive accommodations. Likewise, adaptive and de-adaptive responses were observed. The magnitude and rate of change in the adaptive and de-adaptive responses were similar for persons with TTA and those without an amputation. Furthermore, adaptability was no different based on belt assignment for the prosthetic limb during split adaptation walking. Reactive changes and locomotor adaptation in response to a challenging and novel walking condition were similar in persons with TTA to those without an amputation. Results suggest persons with TTA have the capacity to modify locomotor strategies to meet the demands of most walking conditions despite challenges imposed by an amputation and use of a prosthetic limb.

Evolutionary Construction of Block-Based Neural Networks in Consideration of Failure

NASA Astrophysics Data System (ADS)

Takamori, Masahito; Koakutsu, Seiichi; Hamagami, Tomoki; Hirata, Hironori

In this paper we propose a modified gene coding and an evolutionary construction in consideration of failure in evolutionary construction of Block-Based Neural Networks. In the modified gene coding, we arrange the genes of weights on a chromosome in consideration of the position relation of the genes of weight and structure. By the modified gene coding, the efficiency of search by crossover is increased. Thereby, it is thought that improvement of the convergence rate of construction and shortening of construction time can be performed. In the evolutionary construction in consideration of failure, the structure which is adapted for failure is built in the state where failure occured. Thereby, it is thought that BBNN can be reconstructed in a short time at the time of failure. To evaluate the proposed method, we apply it to pattern classification and autonomous mobile robot control problems. The computational experiments indicate that the proposed method can improve convergence rate of construction and shorten of construction and reconstruction time.

Apparatus for stopping a vehicle

DOEpatents

Wattenburg, Willard H [Walnut Creek, CA; McCallen, David B [Livermore, CA

2007-03-20

An apparatus for externally controlling one or more brakes on a vehicle having a pressurized fluid braking system. The apparatus can include a pressurizable vessel that is adapted for fluid-tight coupling to the braking system. Impact to the rear of the vehicle by a pursuit vehicle, shooting a target mounted on the vehicle or sending a signal from a remote control can all result in the fluid pressures in the braking system of the vehicle being modified so that the vehicle is stopped and rendered temporarily inoperable. A control device can also be provided in the driver's compartment of the vehicle for similarly rendering the vehicle inoperable. A driver or hijacker of the vehicle preferably cannot overcome the stopping action from the driver's compartment.

A rationale for human operator pulsive control behavior

NASA Technical Reports Server (NTRS)

Hess, R. A.

1979-01-01

When performing tracking tasks which involve demanding controlled elements such as those with K/s-squared dynamics, the human operator often develops discrete or pulsive control outputs. A dual-loop model of the human operator is discussed, the dominant adaptive feature of which is the explicit appearance of an internal model of the manipulator-controlled element dynamics in an inner feedback loop. Using this model, a rationale for pulsive control behavior is offered which is based upon the assumption that the human attempts to reduce the computational burden associated with time integration of sensory inputs. It is shown that such time integration is a natural consequence of having an internal representation of the K/s-squared-controlled element dynamics in the dual-loop model. A digital simulation is discussed in which a modified form of the dual-loop model is shown to be capable of producing pulsive control behavior qualitively comparable to that obtained in experiment.

Adaptation of commercial microscopes for advanced imaging applications

NASA Astrophysics Data System (ADS)

Brideau, Craig; Poon, Kelvin; Stys, Peter

2015-03-01

Today's commercially available microscopes offer a wide array of options to accommodate common imaging experiments. Occasionally, an experimental goal will require an unusual light source, filter, or even irregular sample that is not compatible with existing equipment. In these situations the ability to modify an existing microscopy platform with custom accessories can greatly extend its utility and allow for experiments not possible with stock equipment. Light source conditioning/manipulation such as polarization, beam diameter or even custom source filtering can easily be added with bulk components. Custom and after-market detectors can be added to external ports using optical construction hardware and adapters. This paper will present various examples of modifications carried out on commercial microscopes to address both atypical imaging modalities and research needs. Violet and near-ultraviolet source adaptation, custom detection filtering, and laser beam conditioning and control modifications will be demonstrated. The availability of basic `building block' parts will be discussed with respect to user safety, construction strategies, and ease of use.

Unbalance vibration suppression for AMBs system using adaptive notch filter

NASA Astrophysics Data System (ADS)

Chen, Qi; Liu, Gang; Han, Bangcheng

2017-09-01

The unbalance of rotor levitated by active magnetic bearings (AMBs) will cause synchronous vibration which greatly degrade the performance at high speeds in the rotating machinery. To suppress the unbalance vibration without angular velocity information, a novel modified adaptive notch filter (ANF) with phase shift in the AMBs system is presented in this study. Firstly, a 4-degree-of-freedom (DOF) radial unbalanced AMB rotor system is described and analyzed, and the solution of rotor vibration displacement is compared with the experimental data to verify the preciseness of the dynamic model. Then the principle and structure of the proposed notch filter used for the frequency estimation and online identification of synchronous component are presented. As well, the convergence property of the algorithm is investigated. In addition, the stability analysis of the closed-loop AMB system with the proposed ANF is conducted. Simulation and experiments on an AMB driveline system demonstrate the effectiveness and the adaptive characteristics of the proposed ANF on the elimination of synchronous controlled current in a widely operating speed range.

Grid adaption based on modified anisotropic diffusion equations formulated in the parametic domain

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

Hagmeijer, R.

1994-11-01

A new grid-adaption algorithm for problems in computational fluid dynamics is presented. The basic equations are derived from a variational problem formulated in the parametric domain of the mapping that defines the existing grid. Modification of the basic equations provides desirable properties in boundary layers. The resulting modified anisotropic diffusion equations are solved for the computational coordinates as functions of the parametric coordinates and these functions are numerically inverted. Numerical examples show that the algorithm is robust, that shocks and boundary layers are well-resolved on the adapted grid, and that the flow solution becomes a globally smooth function of themore » computational coordinates.« less

Effects of nicergoline on rabbit electroretinogram during recovery after ischaemia in light and dark.

PubMed

Blasco, G; Traversa, U; Drago, F

1997-11-01

Nicergoline is an ergot alkaloid derivative acting as a neuroprotective agent. In the present investigation, b-wave time-course recovery profiles under both light- and dark-adapted conditions, were studied in order to evaluate the possible effectiveness of nicergoline in the protection of the rabbit retina. Retinal ischaemia was induced by bilateral occlusion of common carotid artery in male rabbit of the Dutch strain. Groups of animals were subjected to 15-, 30- and 60-min periods of ischaemia under pentobarbital anaesthesia. Electroretinogram recordings were simultaneously obtained from both eyes, using, as the stimulus, the brightest flash from a stimulator positioned 15 cm in front of each eye. The treatment with nicergoline, administered immediately before the carotid occlusion, induced a significant protection only when the ischaemia seemed to cause retinal damage that the reperfusion alone was not able to recover completely. Nicergoline did not modify the recovery rate after 15-min or 30-min light-adapted and 15-min dark-adapted ischaemia; in these conditions the controls showed a full recovery. After 30-min dark-adapted ischaemia, the maximum recovery of the controls was 82%, and nicergoline significantly improved b-wave amplitude at all time points of reperfusion up to the complete recovery. Rabbit retina was irreversibly damaged by a 60-min ischaemia. In these conditions nicergoline significantly increased the percentage of b-wave recovery both in light- and dark-adapted ERG. Nicergoline, probably on the basis of its metabolic actions, seems to be effective in severe conditions of hypoxia and is more potent in dark than in light-adapted conditions. Its effectiveness in these experimental conditions could be justified by the different oxygen consumption of the photoreceptors in light and dark and the different sensitivity of cones and rods to the ischaemia.

Adaptation of a difficult-to-manage asthma programme for implementation in the Dutch context: a modified e-Delphi.

PubMed

Honkoop, Persijn J; Pinnock, Hilary; Kievits-Smeets, Regien M M; Sterk, Peter J; Dekhuijzen, P N Richard; In 't Veen, Johannes C C M

2017-02-09

Patients with difficult-to-manage asthma represent a heterogeneous subgroup of asthma patients who require extensive assessment and tailored management. The International Primary Care Respiratory Group approach emphasises the importance of differentiating patients with asthma that is difficult to manage from those with severe disease. Local adaptation of this approach, however, is required to ensure an appropriate strategy for implementation in the Dutch context. We used a modified three-round e-Delphi approach to assess the opinion of all relevant stakeholders (general practitioners, pulmonologists, practice nurses, pulmonary nurses and people with asthma). In the first round, the participants were asked to provide potentially relevant items for a difficult-to-manage asthma programme, which resulted in 67 items. In the second round, we asked participants to rate the relevance of specific items on a seven-point Likert scale, and 46 items were selected as relevant. In the third round, the selected items were categorised and items were ranked within the categories according to relevance. Finally, we created the alphabet acronym for the categories 'the A-I of difficult-to-manage asthma' to resonate with an established Dutch 'A-E acronym for determining asthma control'. This should facilitate implementation of this programme within the existing structure of educational material on asthma and chronic obstructive pulmonary disease (COPD) in primary care, with potential for improving management of difficult-to-manage asthma. Other countries could use a similar approach to create a locally adapted version of such a programme.

Conflict adaptation in emotional task underlies the amplification of target.

PubMed

Chechko, Natalia; Kellermann, Thilo; Schneider, Frank; Habel, Ute

2014-04-01

A primary function of cognitive control is to adjust the cognitive system according to situational demands. The so-called "conflict adaptation effect" elicited in laboratory experiments is supposed to reflect the above function. Neuroimaging studies suggest that adaptation of nonemotional conflict is mediated by the dorsolateral prefrontal cortex through a top-down enhancement of task-relevant (target), relative to task-irrelevant (distractor), stimulus representation in the sensory cortices. The adaptation of emotional conflict, on the other hand, is suggested to be related to the rostral anterior cingulate inhibiting the processing of emotional distractors through a top-down modulation of amygdala responsivity. In the present study, we manipulated, on a trial-by-trial basis, the levels of semantic interference conflict triggered by the incompatibility between emotional faces (targets) and emotional words (distractors) in a modified version of the emotional Stroop task. Similar to previous observations involving nonemotional interference effects, the behavioral adaptation of emotional conflict was found to be paralleled by a stronger recruitment of the fusiform face area. Additional areas related to the conflict adaptation effect were the bilateral insula, the bilateral frontal operculum (fO), the right amygdala, the left precentral and postcentral gyri, and the parietal cortex. These findings suggest that augmentation of cortical responses to task-relevant information in emotional conflict may be related to conflict adaptation processes in a way that has been observed in nonemotional conflict, challenging the view that brain circuitries underlying the conflict adaptation effect depend only on the nature of conflict.

Adaptation of reach-to-grasp movement in response to force perturbations.

PubMed

Rand, M K; Shimansky, Y; Stelmach, G E; Bloedel, J R

2004-01-01

This study examined how reach-to-grasp movements are modified during adaptation to external force perturbations applied on the arm during reach. Specifically, we examined whether the organization of these movements was dependent upon the condition under which the perturbation was applied. In response to an auditory signal, all subjects were asked to reach for a vertical dowel, grasp it between the index finger and thumb, and lift it a short distance off the table. The subjects were instructed to do the task as fast as possible. The perturbation was an elastic load acting on the wrist at an angle of 105 deg lateral to the reaching direction. The condition was modified by changing the predictability with which the perturbation was applied in a given trial. After recording unperturbed control trials, perturbations were applied first on successive trials (predictable perturbations) and then were applied randomly (unpredictable perturbations). In the early predictable perturbation trials, reach path length became longer and reaching duration increased. As more predictable perturbations were applied, the reach path length gradually decreased and became similar to that of control trials. Reaching duration also decreased gradually as the subjects adapted by exerting force against the perturbation. In addition, the amplitude of peak grip aperture during arm transport initially increased in response to repeated perturbations. During the course of learning, it reached its maximum and thereafter slightly decreased. However, it did not return to the normal level. The subjects also adapted to the unpredictable perturbations through changes in both arm transport and grasping components, indicating that they can compensate even when the occurrence of the perturbation cannot be predicted during the inter-trial interval. Throughout random perturbation trials, large grip aperture values were observed, suggesting that a conservative aperture level is set regardless of whether the reaching arm is perturbed or not. In addition, the results of the predictable perturbations showed that the time from movement onset to the onset of grip aperture closure changed as adaptation occurred. However, the spatial location where the onset of finger closure occurred showed minimum changes with perturbation. These data suggest that the onset of finger closure is dependent upon distance to target rather than the temporal relationship of the grasp relative to the transport phase of the movement.

Multimodal Medical Image Fusion by Adaptive Manifold Filter.

PubMed

Geng, Peng; Liu, Shuaiqi; Zhuang, Shanna

2015-01-01

Medical image fusion plays an important role in diagnosis and treatment of diseases such as image-guided radiotherapy and surgery. The modified local contrast information is proposed to fuse multimodal medical images. Firstly, the adaptive manifold filter is introduced into filtering source images as the low-frequency part in the modified local contrast. Secondly, the modified spatial frequency of the source images is adopted as the high-frequency part in the modified local contrast. Finally, the pixel with larger modified local contrast is selected into the fused image. The presented scheme outperforms the guided filter method in spatial domain, the dual-tree complex wavelet transform-based method, nonsubsampled contourlet transform-based method, and four classic fusion methods in terms of visual quality. Furthermore, the mutual information values by the presented method are averagely 55%, 41%, and 62% higher than the three methods and those values of edge based similarity measure by the presented method are averagely 13%, 33%, and 14% higher than the three methods for the six pairs of source images.

Building Knowledge in the Workplace and Beyond. Curriculum Adaptation Project.

ERIC Educational Resources Information Center

Ballinger, Ronda

A project was conducted to adapt and modify the four-part workplace literacy curriculum previously created by the College of Lake County (Illinois) and six industries in the county in order to improve the usefulness and application of the information in the original curriculum. Information for the adaptation project was generated by instructors…

A Pilot Study of an Adaptive, Idiographic, and Multi-Component Attention Bias Modification Program for Social Anxiety Disorder

PubMed Central

Amir, Nader; Kuckertz, Jennie M.; Strege, Marlene V.

2016-01-01

An attentional bias toward threat may be one mechanism underlying clinical anxiety. Attention bias modification (ABM) aims to reduce symptoms of anxiety disorders by directly modifying this deficit. However, existing ABM training programs have not consistently modified attentional bias and may not reflect optimal learning needs of participants (i.e., lack of explicit instruction, training goal unclear to participants, lack of feedback, non-adaptive, inability to differentiate or target different components of attentional bias). In the current study, we introduce a new adaptive ABM program (AABM) and test its feasibility in individuals with social anxiety disorder. We report task characteristics and preliminary evidence that this task consistently modifies attentional bias and that changes in attentional bias (but not number of trials) correlate with the level of symptom reduction. These results suggest that AABM may be a targeted method for the next generation of studies examining the utility of attention training. PMID:27795598

Identification and real-time position control of a servo-hydraulic rotary actuator by means of a neurobiologically motivated algorithm.

PubMed

Sadeghieh, Ali; Sazgar, Hadi; Goodarzi, Kamyar; Lucas, Caro

2012-01-01

This paper presents a new intelligent approach for adaptive control of a nonlinear dynamic system. A modified version of the brain emotional learning based intelligent controller (BELBIC), a bio-inspired algorithm based upon a computational model of emotional learning which occurs in the amygdala, is utilized for position controlling a real laboratorial rotary electro-hydraulic servo (EHS) system. EHS systems are known to be nonlinear and non-smooth due to many factors such as leakage, friction, hysteresis, null shift, saturation, dead zone, and especially fluid flow expression through the servo valve. The large value of these factors can easily influence the control performance in the presence of a poor design. In this paper, a mathematical model of the EHS system is derived, and then the parameters of the model are identified using the recursive least squares method. In the next step, a BELBIC is designed based on this dynamic model and utilized to control the real laboratorial EHS system. To prove the effectiveness of the modified BELBIC's online learning ability in reducing the overall tracking error, results have been compared to those obtained from an optimal PID controller, an auto-tuned fuzzy PI controller (ATFPIC), and a neural network predictive controller (NNPC) under similar circumstances. The results demonstrate not only excellent improvement in control action, but also less energy consumption. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

Development of a Modified Korean East Asian Student Stress Inventory by Comparing Stress Levels in Medical Students with Those in Non-Medical Students.

PubMed

Shin, Hee Kon; Kang, Seok Hoon; Lim, Sun-Hye; Yang, Jeong Hee; Chae, Sunguk

2016-01-01

Medical students are usually under more stress than that experienced by non-medical students. Stress testing tools for Korean medical students have not been sufficiently studied. Thus, we adapted and modified the East Asian Student Stress Inventory (EASSI), a stress testing tool for Korean students studying abroad, and verified its usefulness as a stress test in Korean university students. We also compared and analyzed stress levels between medical and non-medical students. A questionnaire survey was conducted on medical and non-medical students of a national university, and the responses of 224 students were analyzed for this study. Factor analysis and reliability testing were performed based on data collected for 25 adapted EASSI questions and those on the Korean version of the Global Assessment of Recent Stress Scale (GARSS). A correlation analysis was performed between the 13 modified EASSI questions and the GARSS, and validity of the modified EASSI was verified by directly comparing stress levels between the two student groups. The 13 questions adapted for the EASSI were called the modified EASSI and classified into four factors through a factor analysis and reliability testing. The Pearson's correlation analysis revealed a significant correlation between the modified EASSI and the Korean version of the GARSS, suggesting a complementary strategy of using both tests. The validity and reliability of the EASSI were verified. The modified Korean EASSI could be a useful stress test for Korean medical students. Our results show that medical students were under more stress than that of non-medical students. Thus, these results could be helpful for managing stress in medical students.

Phase and speed synchronization control of four eccentric rotors driven by induction motors in a linear vibratory feeder with unknown time-varying load torques using adaptive sliding mode control algorithm

NASA Astrophysics Data System (ADS)

Kong, Xiangxi; Zhang, Xueliang; Chen, Xiaozhe; Wen, Bangchun; Wang, Bo

2016-05-01

In this paper, phase and speed synchronization control of four eccentric rotors (ERs) driven by induction motors in a linear vibratory feeder with unknown time-varying load torques is studied. Firstly, the electromechanical coupling model of the linear vibratory feeder is established by associating induction motor's model with the dynamic model of the system, which is a typical under actuated model. According to the characteristics of the linear vibratory feeder, the complex control problem of the under actuated electromechanical coupling model converts to phase and speed synchronization control of four ERs. In order to keep the four ERs operating synchronously with zero phase differences, phase and speed synchronization controllers are designed by employing adaptive sliding mode control (ASMC) algorithm via a modified master-slave structure. The stability of the controllers is proved by Lyapunov stability theorem. The proposed controllers are verified by simulation via Matlab/Simulink program and compared with the conventional sliding mode control (SMC) algorithm. The results show the proposed controllers can reject the time-varying load torques effectively and four ERs can operate synchronously with zero phase differences. Moreover, the control performance is better than the conventional SMC algorithm and the chattering phenomenon is attenuated. Furthermore, the effects of reference speed and parametric perturbations are discussed to show the strong robustness of the proposed controllers. Finally, experiments on a simple vibratory test bench are operated by using the proposed controllers and without control, respectively, to validate the effectiveness of the proposed controllers further.

Teacher Made Adaptive and Assistive Aids for Developing Self Help Skills in the Severely Handicapped.

ERIC Educational Resources Information Center

Magnusson, Clifford J.; Justin, Joseph E., III

1981-01-01

The article suggests ways to modify and construct adaptive aids for use in teaching eating and drinking, personal hygiene, and dressing/undressing skills to severely and multiply handicapped students. (CL)

Optimization of two-photon wave function in parametric down conversion by adaptive optics control of the pump radiation.

PubMed

Minozzi, M; Bonora, S; Sergienko, A V; Vallone, G; Villoresi, P

2013-02-15

We present an efficient method for optimizing the spatial profile of entangled-photon wave function produced in a spontaneous parametric down conversion process. A deformable mirror that modifies a wavefront of a 404 nm CW diode laser pump interacting with a nonlinear β-barium borate type-I crystal effectively controls the profile of the joint biphoton function. The use of a feedback signal extracted from the biphoton coincidence rate is used to achieve the optimal wavefront shape. The optimization of the two-photon coupling into two, single spatial modes for correlated detection is used for a practical demonstration of this physical principle.

The shapes of bird beaks are highly controlled by nondietary factors

PubMed Central

Bright, Jen A.; Marugán-Lobón, Jesús; Cobb, Samuel N.

2016-01-01

Bird beaks are textbook examples of ecological adaptation to diet, but their shapes are also controlled by genetic and developmental histories. To test the effects of these factors on the avian craniofacial skeleton, we conducted morphometric analyses on raptors, a polyphyletic group at the base of the landbird radiation. Despite common perception, we find that the beak is not an independently targeted module for selection. Instead, the beak and skull are highly integrated structures strongly regulated by size, with axes of shape change linked to the actions of recently identified regulatory genes. Together, size and integration account for almost 80% of the shape variation seen between different species to the exclusion of morphological dietary adaptation. Instead, birds of prey use size as a mechanism to modify their feeding ecology. The extent to which shape variation is confined to a few major axes may provide an advantage in that it facilitates rapid morphological evolution via changes in body size, but may also make raptors especially vulnerable when selection pressures act against these axes. The phylogenetic position of raptors suggests that this constraint is prevalent in all landbirds and that breaking the developmental correspondence between beak and braincase may be the key novelty in classic passerine adaptive radiations. PMID:27125856

The shapes of bird beaks are highly controlled by nondietary factors.

PubMed

Bright, Jen A; Marugán-Lobón, Jesús; Cobb, Samuel N; Rayfield, Emily J

2016-05-10

Bird beaks are textbook examples of ecological adaptation to diet, but their shapes are also controlled by genetic and developmental histories. To test the effects of these factors on the avian craniofacial skeleton, we conducted morphometric analyses on raptors, a polyphyletic group at the base of the landbird radiation. Despite common perception, we find that the beak is not an independently targeted module for selection. Instead, the beak and skull are highly integrated structures strongly regulated by size, with axes of shape change linked to the actions of recently identified regulatory genes. Together, size and integration account for almost 80% of the shape variation seen between different species to the exclusion of morphological dietary adaptation. Instead, birds of prey use size as a mechanism to modify their feeding ecology. The extent to which shape variation is confined to a few major axes may provide an advantage in that it facilitates rapid morphological evolution via changes in body size, but may also make raptors especially vulnerable when selection pressures act against these axes. The phylogenetic position of raptors suggests that this constraint is prevalent in all landbirds and that breaking the developmental correspondence between beak and braincase may be the key novelty in classic passerine adaptive radiations.

Constraint-induced movement therapy after stroke.

PubMed

Kwakkel, Gert; Veerbeek, Janne M; van Wegen, Erwin E H; Wolf, Steven L

2015-02-01

Constraint-induced movement therapy (CIMT) was developed to overcome upper limb impairments after stroke and is the most investigated intervention for the rehabilitation of patients. Original CIMT includes constraining of the non-paretic arm and task-oriented training. Modified versions also apply constraining of the non-paretic arm, but not as intensive as original CIMT. Behavioural strategies are mostly absent for both modified and original CIMT. With forced use therapy, only constraining of the non-paretic arm is applied. The original and modified types of CIMT have beneficial effects on motor function, arm-hand activities, and self-reported arm-hand functioning in daily life, immediately after treatment and at long-term follow-up, whereas there is no evidence for the efficacy of constraint alone (as used in forced use therapy). The type of CIMT, timing, or intensity of practice do not seem to affect patient outcomes. Although the underlying mechanisms that drive modified and original CIMT are still poorly understood, findings from kinematic studies suggest that improvements are mainly based on adaptations through learning to optimise the use of intact end-effectors in patients with some voluntary motor control of wrist and finger extensors after stroke. Copyright © 2015 Elsevier Ltd. All rights reserved.

The nonlinear modified equation approach to analyzing finite difference schemes

NASA Technical Reports Server (NTRS)

Klopfer, G. H.; Mcrae, D. S.

1981-01-01

The nonlinear modified equation approach is taken in this paper to analyze the generalized Lax-Wendroff explicit scheme approximation to the unsteady one- and two-dimensional equations of gas dynamics. Three important applications of the method are demonstrated. The nonlinear modified equation analysis is used to (1) generate higher order accurate schemes, (2) obtain more accurate estimates of the discretization error for nonlinear systems of partial differential equations, and (3) generate an adaptive mesh procedure for the unsteady gas dynamic equations. Results are obtained for all three areas. For the adaptive mesh procedure, mesh point requirements for equal resolution of discontinuities were reduced by a factor of five for a 1-D shock tube problem solved by the explicit MacCormack scheme.

Performance of a modified feedback loop adaptive array with TVRO satellite signals

NASA Technical Reports Server (NTRS)

Steadman, Karl N.; Gupta, Inder J.; Walton, Eric K.

1990-01-01

Performance of an experimental adaptive antenna array system is evaluated using television receive-only (TVRO) satellite signals. The experimental system is a sidelobe canceller with two auxiliary channels. Modified feedback loops are used to enhance the suppression of weak interfering signals. The modified feedback loops used two spatialy separated antennas, each with an individual amplifier for each auxiliary channel. Thus, the experimental system uses five antenna elements. Instead of using five separate antennas, a reflector antenna with multiple feeds is used to receive signals from various TVRO satellites. The details of the earth station are given. It is shown that the experimental system can null up to two signals originating from interfering TVRO satellites while receiving the signals from a desired TVRO satellite.

Adaptive Interface Approach Using a Real Time Biocybernetic System: Control of Hazardous Awareness

NASA Technical Reports Server (NTRS)

Ray, William J.

2002-01-01

The focus of this current grant was to continue our work which focused on the manner in which psychophysiological markers can be used to index hazardous states of awareness and to explore the feasibility of developing on-line systems that utilize real time feedback to modify on-going behavioral processes. In this work we have incorporated a multifaceted approach which includes psychophysiological, subjective, and performance based measures. We have considered this from both an internal and external perspective as reflected in work from a variety of labs.

Robotic Processing Of Rocket-Engine Nozzles

NASA Technical Reports Server (NTRS)

Gilbert, Jeffrey L.; Maslakowski, John E.; Gutow, David A.; Deily, David C.

1994-01-01

Automated manufacturing cell containing computer-controlled robotic processing system developed to implement some important related steps in fabrication of rocket-engine nozzles. Performs several tedious and repetitive fabrication, measurement, adjustment, and inspection processes and subprocesses now performed manually. Offers advantages of reduced processing time, greater consistency, excellent collection of data, objective inspections, greater productivity, and simplified fixturing. Also affords flexibility: by making suitable changes in hardware and software, possible to modify process and subprocesses. Flexibility makes work cell adaptable to fabrication of heat exchangers and other items structured similarly to rocket nozzles.

Real-time laser cladding control with variable spot size

NASA Astrophysics Data System (ADS)

Arias, J. L.; Montealegre, M. A.; Vidal, F.; Rodríguez, J.; Mann, S.; Abels, P.; Motmans, F.

2014-03-01

Laser cladding processing has been used in different industries to improve the surface properties or to reconstruct damaged pieces. In order to cover areas considerably larger than the diameter of the laser beam, successive partially overlapping tracks are deposited. With no control over the process variables this conduces to an increase of the temperature, which could decrease mechanical properties of the laser cladded material. Commonly, the process is monitored and controlled by a PC using cameras, but this control suffers from a lack of speed caused by the image processing step. The aim of this work is to design and develop a FPGA-based laser cladding control system. This system is intended to modify the laser beam power according to the melt pool width, which is measured using a CMOS camera. All the control and monitoring tasks are carried out by a FPGA, taking advantage of its abundance of resources and speed of operation. The robustness of the image processing algorithm is assessed, as well as the control system performance. Laser power is decreased as substrate temperature increases, thus maintaining a constant clad width. This FPGA-based control system is integrated in an adaptive laser cladding system, which also includes an adaptive optical system that will control the laser focus distance on the fly. The whole system will constitute an efficient instrument for part repair with complex geometries and coating selective surfaces. This will be a significant step forward into the total industrial implementation of an automated industrial laser cladding process.

Genetically modified organisms: an analysis of the regulatory framework currently employed within the European Union.

PubMed

Gent, R N

1999-09-01

Genetic engineering technology is starting to bring many commercial products to the market. These genetically modified organisms (GMOs) and their derived products are subject to topical debate as to their benefits and risks. The strengths and weaknesses of the regulatory framework that controls their development and application is central to the question of whether this technology poses significant risk to the public health during this critical phase of its evolution. A critical review was carried out of the legal framework regulating the contained use, deliberate release and some aspects of consumer protection relevant to the control of GMOs in Europe and the United Kingdom. The current legal framework is failing to provide a speed of adaptation commensurate with the development of the science of genetic engineering; failing to properly respond to democratic control; failing to resolve significant conflict between the protection of free markets and protection of public health and the environment; and failing to implement obligations on biodiversity. The present legal framework must be replaced. Current European Union proposals for new standards of regulation are welcome, but provide only for further incremental change, and do not address some significant fundamental flaws in our current laws.

Differences in lumbopelvic control and occupational behaviours in female nurses with and without a recent history of low back pain due to back injury.

PubMed

Babiolakis, Corinne S; Kuk, Jennifer L; Drake, Janessa D M

2015-01-01

Low back pain is highly prevalent in nurses. This study aimed to determine which physical fitness, physical activity (PA) and biomechanical characteristics most clearly distinguish between nurses with [recently injured (RInj)] and without [not recently injured (NRInj)] a recent back injury. Twenty-seven (8 RInj, 19 NRInj) female nurses completed questionnaires (pain, work, PA), physical fitness, biomechanical and low back discomfort measures, and wore an accelerometer for one work shift. Relative to NRInj nurses, RInj nurses exhibited reduced lumbopelvic control (41.4% more displayed a moderate loss of frontal plane position), less active occupational behaviours (less moderate PA; less patient lifts performed alone; more sitting and less standing time) and more than two times higher low back discomfort scores. Despite no physical fitness differences, the lumbopelvic control, occupational behaviours and discomfort measures differed between nurses with and without recent back injuries. It is unclear whether poor lumbopelvic control is causal or adaptive in RInj nurses and may require further investigation. Practitioner Summary: It is unclear which personal modifiable factors are most clearly associated with low back pain in nurses. Lumbopelvic control was the only performance-based measure to distinguish between nurses with and without recent back injuries. Future research may investigate whether reduced lumbopelvic control is causal or adaptive in recently injured nurses.

Transgenerational Inheritance of Modified DNA Methylation Patterns and Enhanced Tolerance Induced by Heavy Metal Stress in Rice (Oryza sativa L.)

PubMed Central

Xu, Chunming; Lin, Xiuyun; Zang, Qi; Zhuang, Tingting; Jiang, Lili; von Wettstein, Diter; Liu, Bao

2012-01-01

Background DNA methylation is sensitive and responsive to stressful environmental conditions. Nonetheless, the extent to which condition-induced somatic methylation modifications can impose transgenerational effects remains to be fully understood. Even less is known about the biological relevance of the induced epigenetic changes for potentially altered well-being of the organismal progenies regarding adaptation to the specific condition their progenitors experienced. Methodology/Principal Findings We analyzed DNA methylation pattern by gel-blotting at genomic loci representing transposable elements and protein-coding genes in leaf-tissue of heavy metal-treated rice (Oryza sativa) plants (S0), and its three successive organismal generations. We assessed expression of putative genes involved in establishing and/or maintaining DNA methylation patterns by reverse transcription (RT)-PCR. We measured growth of the stressed plants and their unstressed progenies vs. the control plants. We found (1) relative to control, DNA methylation patterns were modified in leaf-tissue of the immediately treated plants, and the modifications were exclusively confined to CHG hypomethylation; (2) the CHG-demethylated states were heritable via both maternal and paternal germline, albeit often accompanying further hypomethylation; (3) altered expression of genes encoding for DNA methyltransferases, DNA glycosylase and SWI/SNF chromatin remodeling factor (DDM1) were induced by the stress; (4) progenies of the stressed plants exhibited enhanced tolerance to the same stress their progenitor experienced, and this transgenerational inheritance of the effect of condition accompanying heritability of modified methylation patterns. Conclusions/Significance Our findings suggest that stressful environmental condition can produce transgenerational epigenetic modifications. Progenies of stressed plants may develop enhanced adaptability to the condition, and this acquired trait is inheritable and accord with transmission of the epigenetic modifications. We suggest that environmental induction of heritable modifications in DNA methylation provides a plausible molecular underpinning for the still contentious paradigm of inheritance of acquired traits originally put forward by Jean-Baptiste Lamarck more than 200 years ago. PMID:22984395

Transgenerational inheritance of modified DNA methylation patterns and enhanced tolerance induced by heavy metal stress in rice (Oryza sativa L.).

PubMed

Ou, Xiufang; Zhang, Yunhong; Xu, Chunming; Lin, Xiuyun; Zang, Qi; Zhuang, Tingting; Jiang, Lili; von Wettstein, Diter; Liu, Bao

2012-01-01

DNA methylation is sensitive and responsive to stressful environmental conditions. Nonetheless, the extent to which condition-induced somatic methylation modifications can impose transgenerational effects remains to be fully understood. Even less is known about the biological relevance of the induced epigenetic changes for potentially altered well-being of the organismal progenies regarding adaptation to the specific condition their progenitors experienced. We analyzed DNA methylation pattern by gel-blotting at genomic loci representing transposable elements and protein-coding genes in leaf-tissue of heavy metal-treated rice (Oryza sativa) plants (S0), and its three successive organismal generations. We assessed expression of putative genes involved in establishing and/or maintaining DNA methylation patterns by reverse transcription (RT)-PCR. We measured growth of the stressed plants and their unstressed progenies vs. the control plants. We found (1) relative to control, DNA methylation patterns were modified in leaf-tissue of the immediately treated plants, and the modifications were exclusively confined to CHG hypomethylation; (2) the CHG-demethylated states were heritable via both maternal and paternal germline, albeit often accompanying further hypomethylation; (3) altered expression of genes encoding for DNA methyltransferases, DNA glycosylase and SWI/SNF chromatin remodeling factor (DDM1) were induced by the stress; (4) progenies of the stressed plants exhibited enhanced tolerance to the same stress their progenitor experienced, and this transgenerational inheritance of the effect of condition accompanying heritability of modified methylation patterns. Our findings suggest that stressful environmental condition can produce transgenerational epigenetic modifications. Progenies of stressed plants may develop enhanced adaptability to the condition, and this acquired trait is inheritable and accord with transmission of the epigenetic modifications. We suggest that environmental induction of heritable modifications in DNA methylation provides a plausible molecular underpinning for the still contentious paradigm of inheritance of acquired traits originally put forward by Jean-Baptiste Lamarck more than 200 years ago.

Hybrid Active/Passive Jet Engine Noise Suppression System

NASA Technical Reports Server (NTRS)

Parente, C. A.; Arcas, N.; Walker, B. E.; Hersh, A. S.; Rice, E. J.

1999-01-01

A novel adaptive segmented liner concept has been developed that employs active control elements to modify the in-duct sound field to enhance the tone-suppressing performance of passive liner elements. This could potentially allow engine designs that inherently produce more tone noise but less broadband noise, or could allow passive liner designs to more optimally address high frequency broadband noise. A proof-of-concept validation program was undertaken, consisting of the development of an adaptive segmented liner that would maximize attenuation of two radial modes in a circular or annular duct. The liner consisted of a leading active segment with dual annuli of axially spaced active Helmholtz resonators, followed by an optimized passive liner and then an array of sensing microphones. Three successively complex versions of the adaptive liner were constructed and their performances tested relative to the performance of optimized uniform passive and segmented passive liners. The salient results of the tests were: The adaptive segmented liner performed well in a high flow speed model fan inlet environment, was successfully scaled to a high sound frequency and successfully attenuated three radial modes using sensor and active resonator arrays that were designed for a two mode, lower frequency environment.

Management and Care of Women With Invasive Cervical Cancer: American Society of Clinical Oncology Resource-Stratified Clinical Practice Guideline.

PubMed

Chuang, Linus T; Temin, Sarah; Camacho, Rolando; Dueñas-Gonzalez, Alfonso; Feldman, Sarah; Gultekin, Murat; Gupta, Vandana; Horton, Susan; Jacob, Graciela; Kidd, Elizabeth A; Lishimpi, Kennedy; Nakisige, Carolyn; Nam, Joo-Hyun; Ngan, Hextan Yuen Sheung; Small, William; Thomas, Gillian; Berek, Jonathan S

2016-10-01

To provide evidence-based, resource-stratified global recommendations to clinicians and policymakers on the management and palliative care of women diagnosed with invasive cervical cancer. ASCO convened a multidisciplinary, multinational panel of cancer control, medical and radiation oncology, health economic, obstetric and gynecologic, and palliative care experts to produce recommendations reflecting resource-tiered settings. A systematic review of literature from 1966 to 2015 failed to yield sufficiently strong quality evidence to support basic- and limited-resource setting recommendations; a formal consensus-based process was used to develop recommendations. A modified ADAPTE process was also used to adapt recommendations from existing guidelines. Five existing sets of guidelines were identified and reviewed, and adapted recommendations form the evidence base. Eight systematic reviews, along with cost-effectiveness analyses, provided indirect evidence to inform the consensus process, which resulted in agreement of 75% or greater. Clinicians and planners should strive to provide access to the most effective evidence-based antitumor and palliative care interventions. If a woman cannot access these within her own or neighboring country or region, she may need to be treated with lower-tier modalities, depending on capacity and resources for surgery, chemotherapy, radiation therapy, and supportive and palliative care. For women with early-stage cervical cancer in basic settings, cone biopsy or extrafascial hysterectomy may be performed. Fertility-sparing procedures or modified radical or radical hysterectomy may be additional options in nonbasic settings. Combinations of surgery, chemotherapy, and radiation therapy (including brachytherapy) should be used for women with stage IB to IVA disease, depending on available resources. Pain control is a vital component of palliative care. Additional information is available at www.asco.org/rs-cervical-cancer-treatment-guideline and www.asco.org/guidelineswiki. It is the view of ASCO that health care providers and health care system decision makers should be guided by the recommendations for the highest stratum of resources available. The guideline is intended to complement but not replace local guidelines.

Nonlinear and Digital Man-machine Control Systems Modeling

NASA Technical Reports Server (NTRS)

Mekel, R.

1972-01-01

An adaptive modeling technique is examined by which controllers can be synthesized to provide corrective dynamics to a human operator's mathematical model in closed loop control systems. The technique utilizes a class of Liapunov functions formulated for this purpose, Liapunov's stability criterion and a model-reference system configuration. The Liapunov function is formulated to posses variable characteristics to take into consideration the identification dynamics. The time derivative of the Liapunov function generate the identification and control laws for the mathematical model system. These laws permit the realization of a controller which updates the human operator's mathematical model parameters so that model and human operator produce the same response when subjected to the same stimulus. A very useful feature is the development of a digital computer program which is easily implemented and modified concurrent with experimentation. The program permits the modeling process to interact with the experimentation process in a mutually beneficial way.

Fundus-controlled two-color dark adaptometry with the Microperimeter MP1.

PubMed

Bowl, Wadim; Stieger, Knut; Lorenz, Birgit

2015-06-01

The aim of this study was to provide fundus-controlled two-color adaptometry with an existing device. A quick and easy approach extends the application possibilities of a commercial fundus-controlled perimeter. An external filter holder was placed in front the objective lens of the MP1 (Nidek, Italy) and fitted with filters to modify background, stimulus intensity, and color. Prior to dark adaptometry, the subject's visual sensitivity profile was measured for red and blue stimuli to determine whether rods or cones or both mediated the absolute threshold. After light adaptation, 20 healthy subjects were investigated with a pattern covering six spots at the posterior pole of the retina up to 45 min of dark adaptation. Thresholds were determined using a 200 ms red Goldmann IV and a blue Goldmann II stimulus. The pre-test sensitivity showed a typical distribution of values along the meridian, with high peripheral light increment sensitivity (LIS) and low central LIS for rods and the reverse for cones. After bleach, threshold recovery had a classic biphasic shape. The absolute threshold was reached after approximately 10 min for the red and 15 min for the blue stimulus. Two-color fundus-controlled adaptometry with a commercial MP1 without internal changes to the device provides a quick and easy examination of rod and cone function during dark adaptation at defined retinal loci of the posterior pole. This innovative method will be helpful to measure rod vs. cone function at known loci of the posterior pole in early stages of retinal degenerations.

Identification of Hot Moments and Hot Spots for Real-Time Adaptive Control of Multi-scale Environmental Sensor Networks

NASA Astrophysics Data System (ADS)

Wietsma, T.; Minsker, B. S.

2012-12-01

Increased sensor throughput combined with decreasing hardware costs has led to a disruptive growth in data volume. This disruption, popularly termed "the data deluge," has placed new demands for cyberinfrastructure and information technology skills among researchers in many academic fields, including the environmental sciences. Adaptive sampling has been well established as an effective means of improving network resource efficiency (energy, bandwidth) without sacrificing sample set quality relative to traditional uniform sampling. However, using adaptive sampling for the explicit purpose of improving resolution over events -- situations displaying intermittent dynamics and unique hydrogeological signatures -- is relatively new. In this paper, we define hot spots and hot moments in terms of sensor signal activity as measured through discrete Fourier analysis. Following this frequency-based approach, we apply the Nyquist-Shannon sampling theorem, a fundamental contribution from signal processing that led to the field of information theory, for analysis of uni- and multivariate environmental signal data. In the scope of multi-scale environmental sensor networks, we present several sampling control algorithms, derived from the Nyquist-Shannon theorem, that operate at local (field sensor), regional (base station for aggregation of field sensor data), and global (Cloud-based, computationally intensive models) scales. Evaluated over soil moisture data, results indicate significantly greater sample density during precipitation events while reducing overall sample volume. Using these algorithms as indicators rather than control mechanisms, we also discuss opportunities for spatio-temporal modeling as a tool for planning/modifying sensor network deployments. Locally adaptive model based on Nyquist-Shannon sampling theorem Pareto frontiers for local, regional, and global models relative to uniform sampling. Objectives are (1) overall sampling efficiency and (2) sampling efficiency during hot moments as identified using heuristic approach.

Active Control of Wind Tunnel Noise

NASA Technical Reports Server (NTRS)

Hollis, Patrick (Principal Investigator)

1991-01-01

The need for an adaptive active control system was realized, since a wind tunnel is subjected to variations in air velocity, temperature, air turbulence, and some other factors such as nonlinearity. Among many adaptive algorithms, the Least Mean Squares (LMS) algorithm, which is the simplest one, has been used in an Active Noise Control (ANC) system by some researchers. However, Eriksson's results, Eriksson (1985), showed instability in the ANC system with an ER filter for random noise input. The Restricted Least Squares (RLS) algorithm, although computationally more complex than the LMS algorithm, has better convergence and stability properties. The ANC system in the present work was simulated by using an FIR filter with an RLS algorithm for different inputs and for a number of plant models. Simulation results for the ANC system with acoustic feedback showed better robustness when used with the RLS algorithm than with the LMS algorithm for all types of inputs. Overall attenuation in the frequency domain was better in the case of the RLS adaptive algorithm. Simulation results with a more realistic plant model and an RLS adaptive algorithm showed a slower convergence rate than the case with an acoustic plant as a delay plant. However, the attenuation properties were satisfactory for the simulated system with the modified plant. The effect of filter length on the rate of convergence and attenuation was studied. It was found that the rate of convergence decreases with increase in filter length, whereas the attenuation increases with increase in filter length. The final design of the ANC system was simulated and found to have a reasonable convergence rate and good attenuation properties for an input containing discrete frequencies and random noise.

Dynamics Control Approaches to Improve Vibratory Environment of the Helicopter Aircrew

NASA Astrophysics Data System (ADS)

Wickramasinghe, Viresh Kanchana

Although helicopter has become a versatile mode of aerial transportation, high vibration levels leads to poor ride quality for its passengers and aircrew. Undesired vibration transmitted through the helicopter seats have been known to cause fatigue and discomfort to the aircrew in the short-term as well as neck strain and back pain injuries due to long-term exposure. This research study investigated the use of novel active as well as passive methodologies integrated in helicopter seats to mitigate the aircrew exposure to high vibration levels. Due to significantly less certification effort required to modify the helicopter seat structure, application of novel technologies to the seat is more practical compared to flight critical components such as the main rotor to reduce aircrew vibration. In particular, this research effort developed a novel adaptive seat mount approach based on active vibration control technology. This novel design that incorporated two stacked piezoelectric actuators as active struts increases the bending stiffness to avoid the low frequency resonance while generating forces to counteract higher harmonic vibration peaks. A real-time controller implemented using a feed-forward algorithm based on adaptive notches counteracted the forced vibration peaks while a robust feedback control algorithm suppressed the resonance modes. The effectiveness of the adaptive seat mount system was demonstrated through extensive closed-loop control tests on a full-scale helicopter seat using representative helicopter floor vibration profiles. Test results concluded that the proposed adaptive seat mount approach based on active control technology is a viable solution for the helicopter seat vibration control application. In addition, a unique flight test using a Bell-412 helicopter demonstrated that the aircrew is exposed to high levels of vibration during flight and that the whole body vibration spectrum varied substantially depending on operating conditions as well as the aircrew configurations. This investigation also demonstrated the suitability of integrating novel energy absorbing cushion materials to the seat as a low cost solution to improve aircrew vibration suppression. Therefore, it was recommended to pursue certification of novel seat cushion materials as a near-term solution to mitigate undesirable occupational health hazards in helicopter aircrew due to vibration exposure.

Clinical Marginal and Internal Adaptation of Maxillary Anterior Single All-Ceramic Crowns and 2-year Randomized Controlled Clinical Trial.

PubMed

Akın, Aslı; Toksavul, Suna; Toman, Muhittin

2015-07-01

The aims of this randomized-controlled clinical trial were to compare marginal and internal adaptation of all-ceramic crowns fabricated with CAD/CAM and heat-pressed (HP) techniques before luting and to evaluate the clinical outcomes at baseline and at 6, 12, and 24 months after luting. Fifteen CAD/CAM (CC) and 15 HP all-ceramic crowns were placed in 15 patients. A silicone replica was obtained to measure marginal and internal adaptation of each all-ceramic crown before luting, and they were sectioned buccolingually and mesiodistally. Marginal and internal adaptations were measured using computerized light microscope at 40× magnification. Clinical evaluations took place at baseline (2 days after luting) and at 6, 12, and 24 months after luting. Replica scores were analyzed with Mann-Whitney U and Student's t-test (α = 0.05). Survival rate of crowns was determined using Kaplan-Meier statistical analysis. The median marginal gap for the CC group was 132.2 μm and was 130.2 μm for the HP group. The mean internal adaptation for the CC group was 220.3 ± 51.3 μm and 210.5 ± 31 μm for the HP group. There were no statistically significant differences with respect to marginal opening (Mann-Whitney U test; p = 0.95) and internal adaptation (Student's t-test; p = 0.535) between the 2 groups. Based on modified Ryge criteria, 100% of the crowns were rated satisfactory during the 2-year period. In this in vivo study, CAD/CAM and HP all-ceramic crowns exhibited similar marginal and internal adaptations. A 100% success rate was recorded for the 15 CAD/CAM and for the 15 HP all-ceramic crowns during the 2-year period. © 2014 by the American College of Prosthodontists.

Initial accuracy assessment of the modified S-LANSS for the detection of neuropathic orofacial pain conditions.

PubMed

Herrero Babiloni, Alberto; Nixdorf, Donald R; Law, Alan S; Moana-Filho, Estephan J; Shueb, Sarah S; Nguyen, Ruby H; Durham, Justin

2017-01-01

To evaluate the accuracy of a questionnaire modified for the identification of intraoral pain with neuropathic characteristics in a clinical orofacial pain sample population. 136 participants with at least one of four orofacial pain diagnoses (temporomandibular disorders [TMD, n = 41], acute dental pain [ADP, n = 41], trigeminal neuralgia [TN, n = 19], persistent dentoalveolar pain disorder [PDAP, n = 14]) and a group of pain-free controls (n = 21) completed the modified S-LANSS, a previously adapted version of the original questionnaire devised to detected patients suffering from intraoral pain with neuropathic characteristics. Psychometric properties (sensitivity, specificity, positive predictive value [PPV], negative predictive value [NPV]) were calculated in two analyses with two different thresholds: (1) Detection of pain with neuropathic characteristics: PDAP + TN were considered positive, and TMD + ADP + controls were considered negative per gold standard (expert opinion). (2) Detection of PDAP: PDAP was considered positive and TMD + ADP were considered negative per gold standard. For both analyses, target values for adequate sensitivity and specificity were defined as ≥ 80%. For detection of orofacial pain with neuropathic characteristics (PDAP + TN), the modified S-LANSS presented with the most optimistic threshold sensitivity of 52% (95% confidence interval [CI], 34-69), specificity of 70% (95% CI, 60-79), PPV of 35% (95% CI, 22-51), and NPV of 82% (95% CI, 72-89). For detection of PDAP only, with the most optimistic threshold sensitivity was 64% (95% CI, 35-87), specificity 63% (95% CI, 52-74), PPV 23% (95% CI, 11-39) and NPV 91% (95% CI, 81-97). Based on a priori defined criteria, the modified S-LANSS did not show adequate accuracy to detect intraoral pain with neuropathic characteristics in a clinical orofacial pain sample.

Adaptive arrays for satellite communications

NASA Technical Reports Server (NTRS)

Gupta, I. J.; Ksienski, A. A.

1984-01-01

The suppression of interfering signals in a satellite communication system was studied. Adaptive arrays are used to suppress interference at the reception site. It is required that the interference be suppressed to very low levels and a modified adaptive circuit is used which accomplishes the desired objective. Techniques for the modification of the transmit patterns to minimize interference with neighboring communication links are explored.

Is increased maternal basking an adaptation or a pre-adaptation to viviparity in lizards?

PubMed

Shine, Richard

2006-06-01

Pregnant females modify their thermoregulatory behaviour in many species of viviparous (live-bearing) reptiles, typically maintaining higher and more stable body temperatures at this time. Such modifications often have been interpreted as adaptations to viviparity, functioning to accelerate embryonic development and/or modify phenotypic traits of hatchlings. An alternative possibility is that similar maternal thermophily may be widespread also in oviparous species and if so, would be a pre-adaptation (rather than an adaptation) to viviparity. Because eggs are retained in utero for a significant proportion of development even in oviparous reptiles, maternal thermophily might confer similar advantages in oviparous as in viviparous taxa. Experimental trials on montane oviparous scincid lizards (Bassiana duperreyi) support the pre-adaptation hypothesis. First, captive females (both reproductive and non-reproductive) selected higher temperatures than males. Second, experimentally imposing thermal regimes on pregnant females significantly affected their oviposition dates and the phenotypic traits (body shape, running speed) of their hatchlings. Thus, as for many other behavioural correlates of pregnancy in viviparous reptiles, maternal thermophily likely may have already been present in the ancestral oviparous taxa that gave rise to present-day viviparous forms.

The muscarinic inhibition of the potassium M-current modulates the action-potential discharge in the vestibular primary-afferent neurons of the rat.

PubMed

Pérez, C; Limón, A; Vega, R; Soto, E

2009-02-18

There is consensus that muscarinic and nicotinic receptors expressed in vestibular hair cells and afferent neurons are involved in the efferent modulation of the electrical activity of the afferent neurons. However the underlying mechanisms of postsynaptic control in neurons are not well understood. In our work we show that the activation of muscarinic receptors in the vestibular neurons modulates the potassium M-current modifying the activity of afferent neurons. Whole-cell patch-clamp recordings were made on vestibular-afferent neurons isolated from Wistar rats (postnatal days 7-10) and held in primary culture (18-24 h). The M-current was studied during its deactivation after depolarizing voltage-clamp pulses. In 68% of the cells studied, those of larger capacitance, the M-current antagonists linopirdine and XE-991 reduced the amplitude of the M-current by 54%+/-7% and 50%+/-3%. The muscarinic-receptor agonist oxotremorine-M also significantly reduced the M-current by 58%+/-12% in the cells. The action of oxotremorine-M was blocked by atropine, thus indicating its cholinergic nature. The erg-channel blocker E-4031 did not significantly modify the M-current amplitude. In current-clamp experiments, linopirdine, XE-991, and oxotremorine-M modified the discharge response to current pulses from single spike to multiple spiking, reducing the adaptation of the electrical discharge. Our results indicate that large soma-size cultured vestibular-afferent neurons (most probably calyx-bearing neurons) express the M-current and that the modulation of this current by activation of muscarinic-receptor reduces its spike-frequency adaptation.

Induction of diapause and seasonal morphs in butterflies and other insects: knowns, unknowns and the challenge of integration

PubMed Central

Nylin, Sören

2013-01-01

The ‘choice’ of whether to enter diapause or to develop directly has profound effects on the life histories of insects, and may thus have cascading consequences such as seasonal morphs and other less obvious forms of seasonal plasticity. Present knowledge of the control of diapause and seasonal morphs at the physiological and molecular levels is briefly reviewed. Examples, mainly derived from personal research (primarily on butterflies), are given as a starting point with the aim of outlining areas of research that are still poorly understood. These include: the role of the direction of change in photoperiod; the role of factors such as temperature and diet in modifying the photoperiodic responses; and the role of sex, parental effects and sex linkage on photoperiodic control. More generally, there is still a limited understanding of how external cues and physiological pathways regulating various traits are interconnected via gene action to form a co-adapted complete phenotype that is adaptive in the wild despite environmental fluctuation and change. PMID:23894219

Memory recall and spike-frequency adaptation

NASA Astrophysics Data System (ADS)

Roach, James P.; Sander, Leonard M.; Zochowski, Michal R.

2016-05-01

The brain can reproduce memories from partial data; this ability is critical for memory recall. The process of memory recall has been studied using autoassociative networks such as the Hopfield model. This kind of model reliably converges to stored patterns that contain the memory. However, it is unclear how the behavior is controlled by the brain so that after convergence to one configuration, it can proceed with recognition of another one. In the Hopfield model, this happens only through unrealistic changes of an effective global temperature that destabilizes all stored configurations. Here we show that spike-frequency adaptation (SFA), a common mechanism affecting neuron activation in the brain, can provide state-dependent control of pattern retrieval. We demonstrate this in a Hopfield network modified to include SFA, and also in a model network of biophysical neurons. In both cases, SFA allows for selective stabilization of attractors with different basins of attraction, and also for temporal dynamics of attractor switching that is not possible in standard autoassociative schemes. The dynamics of our models give a plausible account of different sorts of memory retrieval.

Performance of a modified feedback loop adaptive array with TVRO satellite signals

NASA Technical Reports Server (NTRS)

Steadman, K.; Gupta, I. J.; Walton, E. K.

1990-01-01

The performance of an experimental adaptive antenna array system is evaluated using television-receive-only (TVRO) satellite signals. The experimental system is a sidelobe canceler with two auxiliary channels. Modified feedback loops are used to enhance the suppression of weak interfering signals. The modified feedback loops use two spatially separate antennas, each with an individual amplifier for each auxiliary channel. Thus, the experimental system uses five antenna elements. Instead of using five separate antennas, a reflector antenna with multiple feeds is used to receive signals from various TVRO satellites. The details of the earth station are given. It is shown that the experimental system can null up to two signals originating from interfering TVRO satellites while receiving the signals from a desired TVRO satellite.

A Brazilian Portuguese cross-cultural adaptation of the modified JOA scale for myelopathy.

PubMed

Pratali, Raphael R; Smith, Justin S; Motta, Rodrigo L N; Martins, Samuel M; Motta, Marcel M; Rocha, Ricardo D; Herrero, Carlos Fernando P S

2017-02-01

To develop a version of the modified Japanese Orthopaedic Association (mJOA) scale that had been translated into Portuguese and cross-culturally adapted for the Brazilian population. The well-established process of forward-backward translation was employed along with cross-cultural adaptation. Three bilingual translators (English and native Portuguese) performed the forward translation of the mJOA scale from English to Portuguese based on iterative discussions used to reach a consensus translation. The translated version of the mJOA scale was then back-translated into English by a native English-speaking translator unaware of the concepts involved with the mJOA scale. The original mJOA scale and the back-translated version were compared by a native North American neurosurgeon, and as they were considered equivalent, the final version of the mJOA scale that had been translated into Portuguese and cross-culturally adapted was defined. To facilitate global and cross-cultural comparisons of the severity of cervical myelopathy, this study presents a version of the mJOA scale that was translated into Portuguese and cross-culturally adapted for the Brazilian population.

Frequency domain FIR and IIR adaptive filters

NASA Technical Reports Server (NTRS)

Lynn, D. W.

1990-01-01

A discussion of the LMS adaptive filter relating to its convergence characteristics and the problems associated with disparate eigenvalues is presented. This is used to introduce the concept of proportional convergence. An approach is used to analyze the convergence characteristics of block frequency-domain adaptive filters. This leads to a development showing how the frequency-domain FIR adaptive filter is easily modified to provide proportional convergence. These ideas are extended to a block frequency-domain IIR adaptive filter and the idea of proportional convergence is applied. Experimental results illustrating proportional convergence in both FIR and IIR frequency-domain block adaptive filters is presented.

Analysis of Lactobacillus sakei Mutants Selected after Adaptation to the Gastrointestinal Tracts of Axenic Mice▿ †

PubMed Central

Chiaramonte, Fabrizio; Anglade, Patricia; Baraige, Fabienne; Gratadoux, Jean-Jacques; Langella, Philippe; Champomier-Vergès, Marie-Christine; Zagorec, Monique

2010-01-01

We recently showed that Lactobacillus sakei, a natural meat-borne lactic acid bacterium, can colonize the gastrointestinal tracts (GIT) of axenic mice but that this colonization in the intestinal environment selects L. sakei mutants showing modified colony morphology (small and rough) and cell shape, most probably resulting from the accumulation of various mutations that confer a selective advantage for persistence in the GIT. In the present study, we analyzed such clones, issued from three different L. sakei strains, in order to determine which functions were modified in the mutants. In the elongated filamentous cells of the rough clones, transmission electron microscopy (TEM) analysis showed a septation defect and dotted and slanted black bands, suggesting the presence of a helical structure around the cells. Comparison of the cytoplasmic and cell wall/membrane proteomes of the meat isolate L. sakei 23K and of one of its rough derivatives revealed a modified expression for 38 spots. The expression of six oxidoreductases, several stress proteins, and four ABC transporters was strongly reduced in the GIT-adapted strain, while the actin-like MreB protein responsible for cell shaping was upregulated. In addition, the expression of several enzymes involved in carbohydrate metabolism was modified, which may correlate with the observation of modified growth of mutants on various carbon sources. These results suggest that the modifications leading to a better adaptation to the GIT are pleiotropic and are characterized in a rough mutant by a different stress status, a cell wall modification, and modified use of energy sources, leading to an improved fitness for the colonization of the GIT. PMID:20208026

Adaptive oxide electronics: A review

NASA Astrophysics Data System (ADS)

Ha, Sieu D.; Ramanathan, Shriram

2011-10-01

Novel information processing techniques are being actively explored to overcome fundamental limitations associated with CMOS scaling. A new paradigm of adaptive electronic devices is emerging that may reshape the frontiers of electronics and enable new modalities. Creating systems that can learn and adapt to various inputs has generally been a complex algorithm problem in information science, albeit with wide-ranging and powerful applications from medical diagnosis to control systems. Recent work in oxide electronics suggests that it may be plausible to implement such systems at the device level, thereby drastically increasing computational density and power efficiency and expanding the potential for electronics beyond Boolean computation. Intriguing possibilities of adaptive electronics include fabrication of devices that mimic human brain functionality: the strengthening and weakening of synapses emulated by electrically, magnetically, thermally, or optically tunable properties of materials.In this review, we detail materials and device physics studies on functional metal oxides that may be utilized for adaptive electronics. It has been shown that properties, such as resistivity, polarization, and magnetization, of many oxides can be modified electrically in a non-volatile manner, suggesting that these materials respond to electrical stimulus similarly as a neural synapse. We discuss what device characteristics will likely be relevant for integration into adaptive platforms and then survey a variety of oxides with respect to these properties, such as, but not limited to, TaOx, SrTiO3, and Bi4-xLaxTi3O12. The physical mechanisms in each case are detailed and analyzed within the framework of adaptive electronics. We then review theoretically formulated and current experimentally realized adaptive devices with functional oxides, such as self-programmable logic and neuromorphic circuits. Finally, we speculate on what advances in materials physics and engineering may be needed to realize the full potential of adaptive oxide electronics.

TH-E-BRE-04: An Online Replanning Algorithm for VMAT

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

Ahunbay, E; Li, X; Moreau, M

2014-06-15

Purpose: To develop a fast replanning algorithm based on segment aperture morphing (SAM) for online replanning of volumetric modulated arc therapy (VMAT) with flattening filtered (FF) and flattening filter free (FFF) beams. Methods: A software tool was developed to interface with a VMAT planning system ((Monaco, Elekta), enabling the output of detailed beam/machine parameters of original VMAT plans generated based on planning CTs for FF or FFF beams. A SAM algorithm, previously developed for fixed-beam IMRT, was modified to allow the algorithm to correct for interfractional variations (e.g., setup error, organ motion and deformation) by morphing apertures based on themore » geometric relationship between the beam's eye view of the anatomy from the planning CT and that from the daily CT for each control point. The algorithm was tested using daily CTs acquired using an in-room CT during daily IGRT for representative prostate cancer cases along with their planning CTs. The algorithm allows for restricted MLC leaf travel distance between control points of the VMAT delivery to prevent SAM from increasing leaf travel, and therefore treatment delivery time. Results: The VMAT plans adapted to the daily CT by SAM were found to improve the dosimetry relative to the IGRT repositioning plans for both FF and FFF beams. For the adaptive plans, the changes in leaf travel distance between control points were < 1cm for 80% of the control points with no restriction. When restricted to the original plans' maximum travel distance, the dosimetric effect was minimal. The adaptive plans were delivered successfully with similar delivery times as the original plans. The execution of the SAM algorithm was < 10 seconds. Conclusion: The SAM algorithm can quickly generate deliverable online-adaptive VMAT plans based on the anatomy of the day for both FF and FFF beams.« less

How performance-contingent reward prospect modulates cognitive control: Increased cue maintenance at the cost of decreased flexibility.

PubMed

Hefer, Carmen; Dreisbach, Gesine

2017-10-01

Growing evidence suggests that reward prospect promotes cognitive stability in terms of increased context or cue maintenance. In 3 Experiments, using different versions of the AX-continuous performance task, we investigated whether this reward effect comes at the cost of decreased cognitive flexibility. Experiment 1 shows that the reward induced increase of cue maintenance perseverates even when reward is no longer available. Experiment 2 shows that this reward effect not only survives the withdrawal of reward but also delays the adaptation to changed task conditions that make cue usage maladaptive. And finally in Experiment 3, it is shown that this reduced flexibility to adapt is observed in a more demanding modified version of the AX-continuous performance task and is even stronger under conditions of sustained reward. Taken together, all 3 Experiments thus speak to the idea that the prospect of reward increases cue maintenance and thereby cognitive stability. This increased cognitive stability however comes at the cost of decreased flexibility in terms of delayed adaptation to new reward and task conditions. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Adaptive firefly algorithm: parameter analysis and its application.

PubMed

Cheung, Ngaam J; Ding, Xue-Ming; Shen, Hong-Bin

2014-01-01

As a nature-inspired search algorithm, firefly algorithm (FA) has several control parameters, which may have great effects on its performance. In this study, we investigate the parameter selection and adaptation strategies in a modified firefly algorithm - adaptive firefly algorithm (AdaFa). There are three strategies in AdaFa including (1) a distance-based light absorption coefficient; (2) a gray coefficient enhancing fireflies to share difference information from attractive ones efficiently; and (3) five different dynamic strategies for the randomization parameter. Promising selections of parameters in the strategies are analyzed to guarantee the efficient performance of AdaFa. AdaFa is validated over widely used benchmark functions, and the numerical experiments and statistical tests yield useful conclusions on the strategies and the parameter selections affecting the performance of AdaFa. When applied to the real-world problem - protein tertiary structure prediction, the results demonstrated improved variants can rebuild the tertiary structure with the average root mean square deviation less than 0.4Å and 1.5Å from the native constrains with noise free and 10% Gaussian white noise.

Adaptive Firefly Algorithm: Parameter Analysis and its Application

PubMed Central

Shen, Hong-Bin

2014-01-01

As a nature-inspired search algorithm, firefly algorithm (FA) has several control parameters, which may have great effects on its performance. In this study, we investigate the parameter selection and adaptation strategies in a modified firefly algorithm — adaptive firefly algorithm (AdaFa). There are three strategies in AdaFa including (1) a distance-based light absorption coefficient; (2) a gray coefficient enhancing fireflies to share difference information from attractive ones efficiently; and (3) five different dynamic strategies for the randomization parameter. Promising selections of parameters in the strategies are analyzed to guarantee the efficient performance of AdaFa. AdaFa is validated over widely used benchmark functions, and the numerical experiments and statistical tests yield useful conclusions on the strategies and the parameter selections affecting the performance of AdaFa. When applied to the real-world problem — protein tertiary structure prediction, the results demonstrated improved variants can rebuild the tertiary structure with the average root mean square deviation less than 0.4Å and 1.5Å from the native constrains with noise free and 10% Gaussian white noise. PMID:25397812

Oral delivery of dsRNA by microbes: Beyond pest control.

PubMed

Abrieux, Antoine; Chiu, Joanna C

2016-01-01

RNA interference (RNAi) by oral delivery of dsRNA in insects has great potential as a tool for integrated pest management (IPM), especially with respect to addressing the need to reduce off-target effect and slow down resistance development to chemical insecticides. Employing the natural association existing between insect and yeast, we developed a novel method to enable the knock down of vital genes in the pest insect Drosophila suzukii through oral delivery of species-specific dsRNA using genetically modified Saccharomyces cerevisae. D. suzukii that were fed with our "yeast biopesticide" showed a significant decrease in fitness. In this perspective article, we postulate that this approach could be adapted to a large number of species, given the great diversity of symbiotic interactions involving microorganisms and host species. Furthermore, we speculate that beyond its application as biopesticide, dsRNA delivery by genetically modified microbes can also serve to facilitate reverse genetic applications, specifically in non-model organisms.

Heuristics to Evaluate Interactive Systems for Children with Autism Spectrum Disorder (ASD).

PubMed

Khowaja, Kamran; Salim, Siti Salwah; Asemi, Adeleh

2015-01-01

In this paper, we adapted and expanded a set of guidelines, also known as heuristics, to evaluate the usability of software to now be appropriate for software aimed at children with autism spectrum disorder (ASD). We started from the heuristics developed by Nielsen in 1990 and developed a modified set of 15 heuristics. The first 5 heuristics of this set are the same as those of the original Nielsen set, the next 5 heuristics are improved versions of Nielsen's, whereas the last 5 heuristics are new. We present two evaluation studies of our new heuristics. In the first, two groups compared Nielsen's set with the modified set of heuristics, with each group evaluating two interactive systems. The Nielsen's heuristics were assigned to the control group while the experimental group was given the modified set of heuristics, and a statistical analysis was conducted to determine the effectiveness of the modified set, the contribution of 5 new heuristics and the impact of 5 improved heuristics. The results show that the modified set is significantly more effective than the original, and we found a significant difference between the five improved heuristics and their corresponding heuristics in the original set. The five new heuristics are effective in problem identification using the modified set. The second study was conducted using a system which was developed to ascertain if the modified set was effective at identifying usability problems that could be fixed before the release of software. The post-study analysis revealed that the majority of the usability problems identified by the experts were fixed in the updated version of the system.

LASIC: Light Activated Site-Specific Conjugation of Native IgGs.

PubMed

Hui, James Z; Tamsen, Shereen; Song, Yang; Tsourkas, Andrew

2015-08-19

Numerous biological applications, from diagnostic assays to immunotherapies, rely on the use of antibody-conjugates. The efficacy of these conjugates can be significantly influenced by the site at which Immunoglobulin G (IgG) is modified. Current methods that provide control over the conjugation site, however, suffer from a number of shortfalls and often require large investments of time and cost. We have developed a novel adapter protein that, when activated by long wavelength UV light, can covalently and site-specifically label the Fc region of nearly any native, full-length IgG, including all human IgG subclasses. Labeling occurs with unprecedented efficiency and speed (>90% after 30 min), with no effect on IgG affinity. The adapter domain can be bacterially expressed and customized to contain a variety of moieties (e.g., biotin, azide, fluorophores), making reliable and efficient conjugation of antibodies widely accessible to researchers at large.

PredGuid+A: Orion Entry Guidance Modified for Aerocapture

NASA Technical Reports Server (NTRS)

Lafleur, Jarret

2013-01-01

PredGuid+A software was developed to enable a unique numerical predictor-corrector aerocapture guidance capability that builds on heritage Orion entry guidance algorithms. The software can be used for both planetary entry and aerocapture applications. Furthermore, PredGuid+A implements a new Delta-V minimization guidance option that can take the place of traditional targeting guidance and can result in substantial propellant savings. PredGuid+A allows the user to set a mode flag and input a target orbit's apoapsis and periapsis. Using bank angle control, the guidance will then guide the vehicle to the appropriate post-aerocapture orbit using one of two algorithms: Apoapsis Targeting or Delta-V Minimization (as chosen by the user). Recently, the PredGuid guidance algorithm was adapted for use in skip-entry scenarios for NASA's Orion multi-purpose crew vehicle (MPCV). To leverage flight heritage, most of Orion's entry guidance routines are adapted from the Apollo program.

Genetic and epigenetic control of gene expression by CRISPR–Cas systems

PubMed Central

Lo, Albert; Qi, Lei

2017-01-01

The discovery and adaption of bacterial clustered regularly interspaced short palindromic repeats (CRISPR)–CRISPR-associated (Cas) systems has revolutionized the way researchers edit genomes. Engineering of catalytically inactivated Cas variants (nuclease-deficient or nuclease-deactivated [dCas]) combined with transcriptional repressors, activators, or epigenetic modifiers enable sequence-specific regulation of gene expression and chromatin state. These CRISPR–Cas-based technologies have contributed to the rapid development of disease models and functional genomics screening approaches, which can facilitate genetic target identification and drug discovery. In this short review, we will cover recent advances of CRISPR–dCas9 systems and their use for transcriptional repression and activation, epigenome editing, and engineered synthetic circuits for complex control of the mammalian genome. PMID:28649363

Plasticity of Hippocampal Excitatory-Inhibitory Balance: Missing the Synaptic Control in the Epileptic Brain.

PubMed

Bonansco, Christian; Fuenzalida, Marco

2016-01-01

Synaptic plasticity is the capacity generated by experience to modify the neural function and, thereby, adapt our behaviour. Long-term plasticity of glutamatergic and GABAergic transmission occurs in a concerted manner, finely adjusting the excitatory-inhibitory (E/I) balance. Imbalances of E/I function are related to several neurological diseases including epilepsy. Several evidences have demonstrated that astrocytes are able to control the synaptic plasticity, with astrocytes being active partners in synaptic physiology and E/I balance. Here, we revise molecular evidences showing the epileptic stage as an abnormal form of long-term brain plasticity and propose the possible participation of astrocytes to the abnormal increase of glutamatergic and decrease of GABAergic neurotransmission in epileptic networks.

Plasticity of Hippocampal Excitatory-Inhibitory Balance: Missing the Synaptic Control in the Epileptic Brain

PubMed Central

Bonansco, Christian; Fuenzalida, Marco

2016-01-01

Synaptic plasticity is the capacity generated by experience to modify the neural function and, thereby, adapt our behaviour. Long-term plasticity of glutamatergic and GABAergic transmission occurs in a concerted manner, finely adjusting the excitatory-inhibitory (E/I) balance. Imbalances of E/I function are related to several neurological diseases including epilepsy. Several evidences have demonstrated that astrocytes are able to control the synaptic plasticity, with astrocytes being active partners in synaptic physiology and E/I balance. Here, we revise molecular evidences showing the epileptic stage as an abnormal form of long-term brain plasticity and propose the possible participation of astrocytes to the abnormal increase of glutamatergic and decrease of GABAergic neurotransmission in epileptic networks. PMID:27006834

Harnessing Protocolized Adaptation in Dissemination: Successful Implementation and Sustainment of the Veterans Affairs Coordinated-Transitional Care Program in a Non-Veterans Affairs Hospital.

PubMed

Kind, Amy J H; Brenny-Fitzpatrick, Maria; Leahy-Gross, Kris; Mirr, Jacquelyn; Chapman, Elizabeth; Frey, Brooke; Houlahan, Beth

2016-02-01

The Department of Veterans Affairs (VA) Coordinated-Transitional Care (C-TraC) program is a low-cost transitional care program that uses hospital-based nurse case managers, inpatient team integration, and in-depth posthospital telephone contacts to support high-risk patients and their caregivers as they transition from hospital to community. The low-cost, primarily telephone-based C-TraC program reduced 30-day rehospitalizations by one-third, leading to significant cost savings at one VA hospital. Non-VA hospitals have expressed interest in launching C-TraC, but non-VA hospitals differ in important ways from VA hospitals, particularly in terms of context, culture, and resources. The objective of this project was to adapt C-TraC to the specific context of one non-VA setting using a modified Replicating Effective Programs (REP) implementation theory model and to test the feasibility of this protocolized implementation approach. The modified REP model uses a mentored phased-based implementation with intensive preimplementation activities and harnesses key local stakeholders to adapt processes and goals to local context. Using this protocolized implementation approach, an adapted C-TraC protocol was created and launched at the non-VA hospital in July 2013. In its first 16 months, C-TraC successfully enrolled 1,247 individuals with 3.2 full-time nurse case managers, achieving good fidelity for core protocol steps. C-TraC participants experienced a 30-day rehospitalization rate of 10.8%, compared with 16.6% for a contemporary comparison group of similar individuals for whom C-TraC was not available (n = 1,307) (P < .001). The new C-TraC program continues in operation. Use of a modified REP model to guide protocolized adaptation to local context resulted in a C-TraC program that was feasible and sustained in a real-world non-VA setting. A modified REP implementation framework may be an appropriate foundational step for other clinical programs seeking to harness protocolized adaptation in mentored dissemination activities. © 2016, Copyright the Authors Journal compilation © 2016, The American Geriatrics Society.

50 CFR 216.275 - Requirements for monitoring and reporting.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Navy shall complete an Integrated Comprehensive Monitoring Plan (ICMP) in 2009. This planning and adaptive management tool shall include: (1) A method for prioritizing monitoring projects that clearly... potentially modify subsequent monitoring and mitigation. (4) An adaptive management plan. (5) A method for...

Sporophytic self-incompatibility in Senecio squalidus (Asteraceae): S allele dominance interactions and modifiers of cross-compatibility and selfing rates

PubMed Central

Brennan, A C; Tabah, D A; Harris, S A; Hiscock, S J

2011-01-01

Understanding genetic mechanisms of self-incompatibility (SI) and how they evolve is central to understanding the mating behaviour of most outbreeding angiosperms. Sporophytic SI (SSI) is controlled by a single multi-allelic locus, S, which is expressed in the diploid (sporophyte) plant to determine the SI phenotype of its haploid (gametophyte) pollen. This allows complex patterns of independent S allele dominance interactions in male (pollen) and female (pistil) reproductive tissues. Senecio squalidus is a useful model for studying the genetic regulation and evolution of SSI because of its population history as an alien invasive species in the UK. S. squalidus maintains a small number of S alleles (7–11) with a high frequency of dominance interactions. Some S. squalidus individuals also show partial selfing and/or greater levels of cross-compatibility than expected under SSI. We previously speculated that these might be adaptations to invasiveness. Here we describe a detailed characterization of the regulation of SSI in S. squalidus. Controlled crosses were used to determine the S allele dominance hierarchy of six S alleles and effects of modifiers on cross-compatibility and partial selfing. Complex dominance interactions among S alleles were found with at least three levels of dominance and tissue-specific codominance. Evidence for S gene modifiers that increase selfing and/or cross-compatibility was also found. These empirical findings are discussed in the context of theoretical predictions for maintenance of S allele dominance interactions, and the role of modifier loci in the evolution of SI. PMID:20372180

Sporophytic self-incompatibility in Senecio squalidus (Asteraceae): S allele dominance interactions and modifiers of cross-compatibility and selfing rates.

PubMed

Brennan, A C; Tabah, D A; Harris, S A; Hiscock, S J

2011-01-01

Understanding genetic mechanisms of self-incompatibility (SI) and how they evolve is central to understanding the mating behaviour of most outbreeding angiosperms. Sporophytic SI (SSI) is controlled by a single multi-allelic locus, S, which is expressed in the diploid (sporophyte) plant to determine the SI phenotype of its haploid (gametophyte) pollen. This allows complex patterns of independent S allele dominance interactions in male (pollen) and female (pistil) reproductive tissues. Senecio squalidus is a useful model for studying the genetic regulation and evolution of SSI because of its population history as an alien invasive species in the UK. S. squalidus maintains a small number of S alleles (7-11) with a high frequency of dominance interactions. Some S. squalidus individuals also show partial selfing and/or greater levels of cross-compatibility than expected under SSI. We previously speculated that these might be adaptations to invasiveness. Here we describe a detailed characterization of the regulation of SSI in S. squalidus. Controlled crosses were used to determine the S allele dominance hierarchy of six S alleles and effects of modifiers on cross-compatibility and partial selfing. Complex dominance interactions among S alleles were found with at least three levels of dominance and tissue-specific codominance. Evidence for S gene modifiers that increase selfing and/or cross-compatibility was also found. These empirical findings are discussed in the context of theoretical predictions for maintenance of S allele dominance interactions, and the role of modifier loci in the evolution of SI.

Adaptive control system having hedge unit and related apparatus and methods

NASA Technical Reports Server (NTRS)

Johnson, Eric Norman (Inventor); Calise, Anthony J. (Inventor)

2003-01-01

The invention includes an adaptive control system used to control a plant. The adaptive control system includes a hedge unit that receives at least one control signal and a plant state signal. The hedge unit generates a hedge signal based on the control signal, the plant state signal, and a hedge model including a first model having one or more characteristics to which the adaptive control system is not to adapt, and a second model not having the characteristic(s) to which the adaptive control system is not to adapt. The hedge signal is used in the adaptive control system to remove the effect of the characteristic from a signal supplied to an adaptation law unit of the adaptive control system so that the adaptive control system does not adapt to the characteristic in controlling the plant.

Cross-cultural adaptation and validation of the osteoporosis assessment questionnaire short version (OPAQ-SV) for Chinese osteoporotic fracture females.

PubMed

Zhang, Yin-Ping; Wei, Huan-Huan; Wang, Wen; Xia, Ru-Yi; Zhou, Xiao-Ling; Porr, Caroline; Lammi, Mikko

2016-04-01

The Osteoporosis Assessment Questionnaire Short Version (OPAQ-SV) was cross-culturally adapted to measure health-related quality of life in Chinese osteoporotic fracture females and then validated in China for its psychometric properties. Cross-cultural adaptation, including translation of the original OPAQ-SV into Mandarin Chinese language, was performed according to published guidelines. Validation of the newly cross-culturally adapted OPAQ-SV was conducted by sampling 234 Chinese osteoporotic fracture females and also a control group of 235 Chinese osteoporotic females without fractures, producing robust content, construct, and discriminant validation results. Major categories of reliability were also met: the Cronbach alpha coefficient was 0.975, indicating good internal consistency; the test-retest reliability was 0.80; and principal component analysis resulted in a 6-factor structure explaining 75.847 % of the total variance. Further, the Comparative Fit Index result was 0.922 following the modified model confirmatory factor analysis, and the chi-squared test was 1.98. The root mean squared error of approximation was 0.078. Moreover, significant differences were revealed between females with fractures and those without fractures across all domains (p < 0.001). Overall, the newly cross-culturally adapted OPAQ-SV appears to possess adequate validity and reliability and may be utilized in clinical trials to assess the health-related quality of life in Chinese osteoporotic fracture females.

Process Analytical Technology (PAT): batch-to-batch reproducibility of fermentation processes by robust process operational design and control.

PubMed

Gnoth, S; Jenzsch, M; Simutis, R; Lübbert, A

2007-10-31

The Process Analytical Technology (PAT) initiative of the FDA is a reaction on the increasing discrepancy between current possibilities in process supervision and control of pharmaceutical production processes and its current application in industrial manufacturing processes. With rigid approval practices based on standard operational procedures, adaptations of production reactors towards the state of the art were more or less inhibited for long years. Now PAT paves the way for continuous process and product improvements through improved process supervision based on knowledge-based data analysis, "Quality-by-Design"-concepts, and, finally, through feedback control. Examples of up-to-date implementations of this concept are presented. They are taken from one key group of processes in recombinant pharmaceutical protein manufacturing, the cultivations of genetically modified Escherichia coli bacteria.

Hybrid Adaptive Flight Control with Model Inversion Adaptation

NASA Technical Reports Server (NTRS)

Nguyen, Nhan

2011-01-01

This study investigates a hybrid adaptive flight control method as a design possibility for a flight control system that can enable an effective adaptation strategy to deal with off-nominal flight conditions. The hybrid adaptive control blends both direct and indirect adaptive control in a model inversion flight control architecture. The blending of both direct and indirect adaptive control provides a much more flexible and effective adaptive flight control architecture than that with either direct or indirect adaptive control alone. The indirect adaptive control is used to update the model inversion controller by an on-line parameter estimation of uncertain plant dynamics based on two methods. The first parameter estimation method is an indirect adaptive law based on the Lyapunov theory, and the second method is a recursive least-squares indirect adaptive law. The model inversion controller is therefore made to adapt to changes in the plant dynamics due to uncertainty. As a result, the modeling error is reduced that directly leads to a decrease in the tracking error. In conjunction with the indirect adaptive control that updates the model inversion controller, a direct adaptive control is implemented as an augmented command to further reduce any residual tracking error that is not entirely eliminated by the indirect adaptive control.

Patient-specific guides do not improve accuracy in total knee arthroplasty: a prospective randomized controlled trial.

PubMed

Victor, Jan; Dujardin, Jan; Vandenneucker, Hilde; Arnout, Nele; Bellemans, Johan

2014-01-01

Recently, patient-specific guides (PSGs) have been introduced, claiming a significant improvement in accuracy and reproducibility of component positioning in TKA. Despite intensive marketing by the manufacturers, this claim has not yet been confirmed in a controlled prospective trial. We (1) compared three-planar component alignment and overall coronal mechanical alignment between PSG and conventional instrumentation and (2) logged the need for applying changes in the suggested position of the PSG. In this randomized controlled trial, we enrolled 128 patients. In the PSG cohort, surgical navigation was used as an intraoperative control. When the suggested cut deviated more than 3° from target, the use of PSG was abandoned and marked as an outlier. When cranial-caudal position or size was adapted, the PSG was marked as modified. All patients underwent long-leg standing radiography and CT scan. Deviation of more than 3° from the target in any plane was defined as an outlier. The PSG and conventional cohorts showed similar numbers of outliers in overall coronal alignment (25% versus 28%; p = 0.69), femoral coronal alignment (7% versus 14%) (p = 0.24), and femoral axial alignment (23% versus 17%; p = 0.50). There were more outliers in tibial coronal (15% versus 3%; p = 0.03) and sagittal 21% versus 3%; p = 0.002) alignment in the PSG group than in the conventional group. PSGs were abandoned in 14 patients (22%) and modified in 18 (28%). PSGs do not improve accuracy in TKA and, in our experience, were somewhat impractical in that the procedure needed to be either modified or abandoned with some frequency.

An algorithm for solving an arbitrary triangular fully fuzzy Sylvester matrix equations

NASA Astrophysics Data System (ADS)

Daud, Wan Suhana Wan; Ahmad, Nazihah; Malkawi, Ghassan

2017-11-01

Sylvester matrix equations played a prominent role in various areas including control theory. Considering to any un-certainty problems that can be occurred at any time, the Sylvester matrix equation has to be adapted to the fuzzy environment. Therefore, in this study, an algorithm for solving an arbitrary triangular fully fuzzy Sylvester matrix equation is constructed. The construction of the algorithm is based on the max-min arithmetic multiplication operation. Besides that, an associated arbitrary matrix equation is modified in obtaining the final solution. Finally, some numerical examples are presented to illustrate the proposed algorithm.

Development of flying qualities criteria for single pilot instrument flight operations

NASA Technical Reports Server (NTRS)

Bar-Gill, A.; Nixon, W. B.; Miller, G. E.

1982-01-01

Flying qualities criteria for Single Pilot Instrument Flight Rule (SPIFR) operations were investigated. The ARA aircraft was modified and adapted for SPIFR operations. Aircraft configurations to be flight-tested were chosen and matched on the ARA in-flight simulator, implementing modern control theory algorithms. Mission planning and experimental matrix design were completed. Microprocessor software for the onboard data acquisition system was debugged and flight-tested. Flight-path reconstruction procedure and the associated FORTRAN program were developed. Algorithms associated with the statistical analysis of flight test results and the SPIFR flying qualities criteria deduction are discussed.

50 CFR 217.178 - Renewal of Letters of Authorization and adaptive management.

Code of Federal Regulations, 2011 CFR

2011-10-01

... to Operation and Maintenance of the Neptune Liquefied Natural Gas Facility Off Massachusetts § 217... modify or augment the existing mitigation or monitoring measures (after consulting with Neptune regarding... modify the mitigation or monitoring measures: (1) Results from Neptune's monitoring from the previous...

Overview of the ARPA/WL Smart Structures and Materials Development-Smart Wing contract

NASA Astrophysics Data System (ADS)

Kudva, Jayanth N.; Jardine, A. Peter; Martin, Christopher A.; Appa, Kari

1996-05-01

While the concept of an adaptive aircraft wing, i.e., a wing whose shape parameters such as camber, wing twist, and thickness can be varied to optimize the wing shape for various flight conditions, has been extensively studied, the complexity and weight penalty of the actuation mechanisms have precluded their practical implementation. Recent development of sensors and actuators using smart materials could potentially alleviate the shortcomings of prior designs, paving the way for a practical, `smart' adaptive wing which responds to changes in flight and environmental conditions by modifying its shape to provide optimal performance. This paper presents a summary of recent work done on adaptive wing designs under an on-going ARPA/WL contract entitled `Smart Structures and Materials Development--Smart Wing.' Specifically, the design, development and planned wind tunnel testing of a 16% model representative of a fighter aircraft wing and incorporating the following features, are discussed: (1) a composite wing torque box whose span-wise twist can be varied by activating built-in shape memory alloy (SMA) torque tubes to provide increased lift and enhanced maneuverability at multiple flight conditions, (2) trailing edge control surfaces deployed using composite SMA actuators to provide smooth, hingeless aerodynamic surfaces, and (3) a suite of fiber optic sensors integrated into the wing skin which provide real-time strain and pressure data to a feedback control system.

Adaptive Controller Effects on Pilot Behavior

NASA Technical Reports Server (NTRS)

Trujillo, Anna C.; Gregory, Irene M.; Hempley, Lucas E.

2014-01-01

Adaptive control provides robustness and resilience for highly uncertain, and potentially unpredictable, flight dynamics characteristic. Some of the recent flight experiences of pilot-in-the-loop with an adaptive controller have exhibited unpredicted interactions. In retrospect, this is not surprising once it is realized that there are now two adaptive controllers interacting, the software adaptive control system and the pilot. An experiment was conducted to categorize these interactions on the pilot with an adaptive controller during control surface failures. One of the objectives of this experiment was to determine how the adaptation time of the controller affects pilots. The pitch and roll errors, and stick input increased for increasing adaptation time and during the segment when the adaptive controller was adapting. Not surprisingly, altitude, cross track and angle deviations, and vertical velocity also increase during the failure and then slowly return to pre-failure levels. Subjects may change their behavior even as an adaptive controller is adapting with additional stick inputs. Therefore, the adaptive controller should adapt as fast as possible to minimize flight track errors. This will minimize undesirable interactions between the pilot and the adaptive controller and maintain maneuvering precision.

Susceptibility of a potential animal model for pathological anxiety to chronic mild stress.

PubMed

Salomons, Amber R; Kortleve, Tessa; Reinders, Niels R; Kirchhoff, Susanne; Arndt, Saskia S; Ohl, Frauke

2010-06-19

When anxiety-related behaviour in animals appears to lack adaptive value, it might be defined as pathological. Adaptive behaviour can be assessed for example by changes in behavioural responses over time, i.e. habituation. Thus, non-adaptive anxiety would be reflected by a lack of habituation. Recently, we found that 129P3/J mice are characterised by non-adaptive avoidance behaviour after repeated test exposure. The present study was aimed at investigating the sensitivity of the behavioural profile of these animals to exposure to a chronic mild stress (CMS) paradigm followed by repeated exposure to the modified hole board test. If the behavioural profile of 129P3/J mice mirrors pathological anxiety, their behavioural habituation under repeated test exposure conditions should be affected by CMS treatment. The results confirm the profound lack of habituation with respect to anxiety-related behaviour in both control and CMS treated mice. Additionally, CMS treated animals revealed a lower exploratory behaviour, reduced locomotor activity and increased arousal-related behaviour over time when compared to control individuals, proving an extension of their impaired habituation behaviour. Although no effects of CMS treatment on plasma corticosterone levels were found, higher immediate early gene expression in the bed nucleus of the stria terminalis and the ventrolateral periaqueductal grey in CMS treated mice indicated that 129P3/J mice are susceptible to the negative effects of CMS treatment at both the behavioural and the functional level. These results support the hypothesis that 129P3/J mice might be an interesting model for pathological anxiety. Copyright 2010 Elsevier B.V. All rights reserved.

Application of a modified diabetes prevention program with adolescents.

PubMed

Geria, Kimberly; Beitz, Janice M

2017-12-29

The purpose of this study was to increase type 2 diabetes (T2DM) awareness and decrease T2DM risk factors by examining effectiveness of a modified version of the Centers for Disease Control and Prevention (CDC) Diabetes Prevention Program (DPP) with adolescents. A quasi-experimental one-group, pretest/posttest design was used to determine impact of the modified DPP on adolescents. Study intervention was incorporated into the health education curriculum at a public charter school and implemented over 11 weeks. Study sample included primarily African-American and Hispanic adolescents (N = 101) aged 13-18 attending the public charter school in a New Jersey urban community. Instrumentation included valid, reliable measures of self-efficacy for healthy eating, physical activity, food knowledge, and healthy food choices. Participants' pretest/posttest waist circumference and body mass index (BMI) were collected. Outcomes revealed significant (p < .001) increase in participants' food knowledge, self-efficacy for choosing healthy foods and performing physical activity, healthy food choices, and amount of weekly aerobic exercise. Reductions in BMI and waist circumference were statistically significant (p < .05). A modified DPP adapted for adolescents' learning needs lowered risk for T2DM. Implications for clinical practice, education, and research are posed. © 2017 Wiley Periodicals, Inc.

Nonlinear stability and control study of highly maneuverable high performance aircraft

NASA Technical Reports Server (NTRS)

Mohler, R. R.

1993-01-01

This project is intended to research and develop new nonlinear methodologies for the control and stability analysis of high-performance, high angle-of-attack aircraft such as HARV (F18). Past research (reported in our Phase 1, 2, and 3 progress reports) is summarized and more details of final Phase 3 research is provided. While research emphasis is on nonlinear control, other tasks such as associated model development, system identification, stability analysis, and simulation are performed in some detail as well. An overview of various models that were investigated for different purposes such as an approximate model reference for control adaptation, as well as another model for accurate rigid-body longitudinal motion is provided. Only a very cursory analysis was made relative to type 8 (flexible body dynamics). Standard nonlinear longitudinal airframe dynamics (type 7) with the available modified F18 stability derivatives, thrust vectoring, actuator dynamics, and control constraints are utilized for simulated flight evaluation of derived controller performance in all cases studied.

Socio-cultural adaptation and standardization of Dubois' five words testing in a population of normal subject in Mali, West Africa.

PubMed

Guinto, Cheick O; Coulibaly, Toumany; Koné, Zeinab; Coulibaly, Souleymane; Maiga, Boubacar; Dembélé, Kekouta; Cissé, Lassana; Konaté, Mamadou; Coulibaly, Thomas; Sissoko, Adama S; Karambé, Mamadou; Burnett, Barrington; Landouré, Guida; Traoré, Moussa

2016-06-01

Dubois' five words testing (5WT) is a verbal memory test that depends on many parameters. The aim of this study is to adapt Dubois' 5WT to the Malian socio-cultural conditions to (i) determine performances of normal subjects to the 5WT and (ii) provide reference scores of the 5WT. A sample of 276 normal subjects aged ≥ 50 years (154 males and 122 females; 144 literates and 132 illiterates) were enrolled from February 2008 to January 2009. Subjects with a history of symptoms likely to modify cognitive functions and those who were found disabled under Lawton's four simplified item test were excluded. The learning score in illiterates was 1.51 in Dubois' 5WT and 4.90 in the modified 5WT. The mean value of the modified 5WT total score was 9.71. Majority (90.22%) of the subjects scored the maximum (10). The modified 5WT reduced with both the age (p < 0.006) and education level (p < 0.04). Our results show that Dubois' 5WT is influenced by culture and the socio-educative level in French. Its adaptation to the socio-cultural context could prove useful and efficient in countries with a low literacy rate and a diverse cultural background.

Balancing Flexible Constraints and Measurement Precision in Computerized Adaptive Testing

ERIC Educational Resources Information Center

Moyer, Eric L.; Galindo, Jennifer L.; Dodd, Barbara G.

2012-01-01

Managing test specifications--both multiple nonstatistical constraints and flexibly defined constraints--has become an important part of designing item selection procedures for computerized adaptive tests (CATs) in achievement testing. This study compared the effectiveness of three procedures: constrained CAT, flexible modified constrained CAT,…

Catalog of Exemplary Projects, 1985-86.

ERIC Educational Resources Information Center

Virginia Community Coll. System, Sterling. Inst. for Instructional Excellence.

Brief descriptions are provided of 39 activities funded through the Virginia Community College Institute for Instructional Excellence, including efforts to adapt and/or modify a teaching practice developed by a colleague or documented in the literature (funded by Adapter Grants), to develop and implement innovative teaching practices (funded by…

A Culturally Adapted Physical Activity intervention for Latinas A Randomized Controlled Trial

PubMed Central

Pekmezi, Dorothy W.; Neighbors, Charles J.; Lee, Christina S.; Gans, Kim M.; Bock, Beth C.; Morrow, Kathleen M.; Marquez, Becky; Dunsiger, Shira; Marcus, Bess H.

2010-01-01

Background In the U.S., Latinos report particularly high levels of inactivity and related chronic illnesses and are in need of intervention. Thus, the purpose of the current study was to culturally and linguistically adapt an empirically supported, individually tailored physical activity print intervention for Latinos and then conduct an RCT of the modified program. Design RCT Setting/Participants The sample included 93 overweight/obese (80%) Latinas with low income and acculturation. Intervention Data were collected in 2007–2008 and analyzed by intent-to-treat in 2009. Participants were randomly assigned to either: (1) a culturally and linguistically adapted physical activity intervention (Seamos Activas), or (2) a wellness contact control condition. Main outcome measures Self report physical activity, as measured pre- and post- intervention (6 months, 87% retention) by the 7-Day Physical Activity Recall. Results Moderate-intensity (or greater) physical activity increased from an average of 16.56 minutes/week (SD=25.76) at baseline to 147.27 (SD=241.55) at 6 months in the intervention arm (n=45) and from 11.88 minutes/week (SD=21.99) to 96.79 (SD=118.49) in the wellness contact control arm (n=48). No between-group differences were seen in overall physical activity. Intervention participants reported significantly greater increases in cognitive [F(1,91)= 9.53, p = .003] and behavioral processes of change [F(1,91)= 8.37, p = .005] and available physical activity supplies and equipment at home [F(1,91)=4.17, p=.04] than control participants. Conclusions Results supported the hypothesized feasibility, acceptability, and preliminary efficacy of individually tailored physical activity print interventions among Latinas. While more research is needed to corroborate these findings, such high-reach, low-cost approaches have great potential to positively affect public health. PMID:19944914

Cross-cultural adaptation of the Window to Hope: a psychological intervention to reduce hopelessness among U.S. veterans with traumatic brain injury.

PubMed

Matarazzo, Bridget B; Hoffberg, Adam S; Clemans, Tracy A; Signoracci, Gina M; Simpson, Grahame K; Brenner, Lisa A

2014-01-01

To conduct a cross-cultural adaptation of Window to Hope (WtoH), a treatment to reduce hopelessness after traumatic brain injury (TBI), from the Australian civilian context to that of U.S. Veterans. Three-stage mixed-methods approach. Stage 1: Consensus conference with stakeholders to revise the manual. Stage 2: Pilot study of the revised manual with US Veterans to examine acceptability, feasibility and fidelity. Stage 3: Review of results with consensus conference attendees and further revisions. Stage 1: Conference attendees reached 100% consensus regarding changes made to the manual. Stage 2: Qualitative results yielded themes that suggest that participants benefitted from the intervention and that multiple factors contributed to successful implementation (Narrative Evaluation of Intervention Interview, User Feedback Survey-Modified, Post-Treatment Interviews). Therapists achieved 100% treatment fidelity. Quantitative results from the Client Satisfaction Questionnaire-8 suggest that the intervention was acceptable. Stage 3: The culturally adapted manual was finalized. RESULTS of this study suggest that the revised WtoH manual is acceptable and feasible. US therapists exhibited adherence to the protocol. The three-stage methodology was successfully employed to cross-culturally adapt an intervention that is well-suited for a Phase II randomized controlled trial among US military Veterans.

The innate and adaptive infiltrating immune systems as targets for breast cancer immunotherapy

PubMed Central

Law, Andrew M K; Lim, Elgene; Ormandy, Christopher J

2017-01-01

A cancer cell-centric view has long dominated the field of cancer biology. Research efforts have focussed on aberrant cancer cell signalling pathways and on changes to cancer cell DNA. Mounting evidence demonstrates that many cancer-associated cell types within the tumour stroma co-evolve and support tumour growth and development, greatly modifying cancer cell behaviour, facilitating invasion and metastasis and controlling dormancy and sensitivity to drug therapy. Thus, these stromal cells represent potential targets for cancer therapy. Among these cell types, immune cells have emerged as a promising target for therapy. The adaptive and the innate immune system play an important role in normal mammary development and breast cancer. The number of infiltrating adaptive immune system cells with tumour-rejecting capacity, primarily, T lymphocytes, is lower in breast cancer compared with other cancer types, but infiltration occurs in a large proportion of cases. There is strong evidence demonstrating the importance of the immunosuppressive role of the innate immune system during breast cancer progression. A consideration of components of both the innate and the adaptive immune system is essential for the design and development of immunotherapies in breast cancer. In this review, we focus on the importance of immunosuppressive myeloid-derived suppressor cells (MDSCs) as potential targets for breast cancer therapy. PMID:28193698

The innate and adaptive infiltrating immune systems as targets for breast cancer immunotherapy.

PubMed

Law, Andrew M K; Lim, Elgene; Ormandy, Christopher J; Gallego-Ortega, David

2017-04-01

A cancer cell-centric view has long dominated the field of cancer biology. Research efforts have focussed on aberrant cancer cell signalling pathways and on changes to cancer cell DNA. Mounting evidence demonstrates that many cancer-associated cell types within the tumour stroma co-evolve and support tumour growth and development, greatly modifying cancer cell behaviour, facilitating invasion and metastasis and controlling dormancy and sensitivity to drug therapy. Thus, these stromal cells represent potential targets for cancer therapy. Among these cell types, immune cells have emerged as a promising target for therapy. The adaptive and the innate immune system play an important role in normal mammary development and breast cancer. The number of infiltrating adaptive immune system cells with tumour-rejecting capacity, primarily, T lymphocytes, is lower in breast cancer compared with other cancer types, but infiltration occurs in a large proportion of cases. There is strong evidence demonstrating the importance of the immunosuppressive role of the innate immune system during breast cancer progression. A consideration of components of both the innate and the adaptive immune system is essential for the design and development of immunotherapies in breast cancer. In this review, we focus on the importance of immunosuppressive myeloid-derived suppressor cells (MDSCs) as potential targets for breast cancer therapy. © 2017 The authors.

Adaptive Ambient Illumination Based on Color Harmony Model

NASA Astrophysics Data System (ADS)

Kikuchi, Ayano; Hirai, Keita; Nakaguchi, Toshiya; Tsumura, Norimichi; Miyake, Yoichi

We investigated the relationship between ambient illumination and psychological effect by applying a modified color harmony model. We verified the proposed model by analyzing correlation between psychological value and modified color harmony score. Experimental results showed the possibility to obtain the best color for illumination using this model.

VisAdapt: A Visualization Tool to Support Climate Change Adaptation.

PubMed

Johansson, Jimmy; Opach, Tomasz; Glaas, Erik; Neset, Tina-Simone; Navarra, Carlo; Linner, Bjorn-Ola; Rod, Jan Ketil

2017-01-01

The web-based visualization VisAdapt tool was developed to help laypeople in the Nordic countries assess how anticipated climate change will impact their homes. The tool guides users through a three-step visual process that helps them explore risks and identify adaptive actions specifically modified to their location and house type. This article walks through the tool's multistep, user-centered design process. Although VisAdapt's target end users are Nordic homeowners, the insights gained from the development process and the lessons learned from the project are applicable to a wide range of domains.

Adaptive planning for applications with dynamic objectives

NASA Technical Reports Server (NTRS)

Hadavi, Khosrow; Hsu, Wen-Ling; Pinedo, Michael

1992-01-01

We devise a qualitative control layer to be integrated into a real-time multi-agent reactive planner. The reactive planning system consists of distributed planning agents attending to various perspectives of the task environment. Each perspective corresponds to an objective. The set of objectives considered are sometimes in conflict with each other. Each agent receives information about events as they occur, and a set of actions based on heuristics can be taken by the agents. Within the qualitative control scheme, we use a set of qualitative feature vectors to describe the effects of applying actions. A qualitative transition vector is used to denote the qualitative distance between the current state and the target state. We will then apply on-line learning at the qualitative control level to achieve adaptive planning. Our goal is to design a mechanism to refine the heuristics used by the reactive planner every time an action is taken toward achieving the objectives, using feedback from the results of the actions. When the outcome is compared with expectations, our prior objectives may be modified and a new set of objectives (or a new assessment of the relative importance of the different objectives) can be introduced. Because we are able to obtain better estimates of the time-varying objectives, the reactive strategies can be improved and better prediction can be achieved.

Adaptive Optics: Arroyo Simulation Tool and Deformable Mirror Actuation Using Golay Cells

NASA Technical Reports Server (NTRS)

Lint, Adam S.

2005-01-01

The Arroyo C++ libraries, written by Caltech post-doc student Matthew Britton, have the ability to simulate optical systems and atmospheric signal interference. This program was chosen for use in an end-to-end simulation model of a laser communication system because it is freely distributed and has the ability to be controlled by a remote system or "smart agent." Proposed operation of this program by a smart agent has been demonstrated, and the results show it to be a suitable simulation tool. Deformable mirrors, as a part of modern adaptive optics systems, may contain thousands of tiny, independently controlled actuators used to modify the shape of the mirror. Each actuator is connected to two wires, creating a cumbersome and expensive device. Recently, an alternative actuation method that uses gas-filled tubes known as Golay cells has been explored. Golay cells, operated by infrared lasers instead of electricity, would replace the actuator system thereby creating a more compact deformable mirror. The operation of Golay cells and their ability to move a deformable mirror in excess of the required 20 microns has been demonstrated. Experimentation has shown them to be extremely sensitive to pressure and temperature, making them ideal for use in a controlled environment.

From Fault-Diagnosis and Performance Recovery of a Controlled System to Chaotic Secure Communication

NASA Astrophysics Data System (ADS)

Hsu, Wen-Teng; Tsai, Jason Sheng-Hong; Guo, Fang-Cheng; Guo, Shu-Mei; Shieh, Leang-San

Chaotic systems are often applied to encryption on secure communication, but they may not provide high-degree security. In order to improve the security of communication, chaotic systems may need to add other secure signals, but this may cause the system to diverge. In this paper, we redesign a communication scheme that could create secure communication with additional secure signals, and the proposed scheme could keep system convergence. First, we introduce the universal state-space adaptive observer-based fault diagnosis/estimator and the high-performance tracker for the sampled-data linear time-varying system with unanticipated decay factors in actuators/system states. Besides, robustness, convergence in the mean, and tracking ability are given in this paper. A residual generation scheme and a mechanism for auto-tuning switched gain is also presented, so that the introduced methodology is applicable for the fault detection and diagnosis (FDD) for actuator and state faults to yield a high tracking performance recovery. The evolutionary programming-based adaptive observer is then applied to the problem of secure communication. Whenever the tracker induces a large control input which might not conform to the input constraint of some physical systems, the proposed modified linear quadratic optimal tracker (LQT) can effectively restrict the control input within the specified constraint interval, under the acceptable tracking performance. The effectiveness of the proposed design methodology is illustrated through tracking control simulation examples.

An evidence-based public health approach to climate change adaptation.

PubMed

Hess, Jeremy J; Eidson, Millicent; Tlumak, Jennifer E; Raab, Kristin K; Luber, George

2014-11-01

Public health is committed to evidence-based practice, yet there has been minimal discussion of how to apply an evidence-based practice framework to climate change adaptation. Our goal was to review the literature on evidence-based public health (EBPH), to determine whether it can be applied to climate change adaptation, and to consider how emphasizing evidence-based practice may influence research and practice decisions related to public health adaptation to climate change. We conducted a substantive review of EBPH, identified a consensus EBPH framework, and modified it to support an EBPH approach to climate change adaptation. We applied the framework to an example and considered implications for stakeholders. A modified EBPH framework can accommodate the wide range of exposures, outcomes, and modes of inquiry associated with climate change adaptation and the variety of settings in which adaptation activities will be pursued. Several factors currently limit application of the framework, including a lack of higher-level evidence of intervention efficacy and a lack of guidelines for reporting climate change health impact projections. To enhance the evidence base, there must be increased attention to designing, evaluating, and reporting adaptation interventions; standardized health impact projection reporting; and increased attention to knowledge translation. This approach has implications for funders, researchers, journal editors, practitioners, and policy makers. The current approach to EBPH can, with modifications, support climate change adaptation activities, but there is little evidence regarding interventions and knowledge translation, and guidelines for projecting health impacts are lacking. Realizing the goal of an evidence-based approach will require systematic, coordinated efforts among various stakeholders.

Robust Optimal Adaptive Control Method with Large Adaptive Gain

NASA Technical Reports Server (NTRS)

Nguyen, Nhan T.

2009-01-01

In the presence of large uncertainties, a control system needs to be able to adapt rapidly to regain performance. Fast adaptation is referred to the implementation of adaptive control with a large adaptive gain to reduce the tracking error rapidly. However, a large adaptive gain can lead to high-frequency oscillations which can adversely affect robustness of an adaptive control law. A new adaptive control modification is presented that can achieve robust adaptation with a large adaptive gain without incurring high-frequency oscillations as with the standard model-reference adaptive control. The modification is based on the minimization of the Y2 norm of the tracking error, which is formulated as an optimal control problem. The optimality condition is used to derive the modification using the gradient method. The optimal control modification results in a stable adaptation and allows a large adaptive gain to be used for better tracking while providing sufficient stability robustness. Simulations were conducted for a damaged generic transport aircraft with both standard adaptive control and the adaptive optimal control modification technique. The results demonstrate the effectiveness of the proposed modification in tracking a reference model while maintaining a sufficient time delay margin.

The Effect of a New Therapy for Children with Tics Targeting Underlying Cognitive, Behavioral, and Physiological Processes

PubMed Central

Leclerc, Julie B.; O’Connor, Kieron P.; J.-Nolin, Gabrielle; Valois, Philippe; Lavoie, Marc E.

2016-01-01

Tourette disorder (TD) is characterized by motor and vocal tics, and children with TD tend to present a lower quality of life than neurotypical children. This study applied a manualized treatment for childhood tics disorder, Facotik, to a consecutive case series of children aged 8–12 years. The Facotik therapy was adapted from the adult cognitive and psychophysiological program validated on a range of subtypes of tics. This approach aims to modify the cognitive–behavioral and physiological processes against which the tic occurs, rather than only addressing the tic behavior. The Facotik therapy lasted 12–14 weeks. Each week 90-min session contained 20 min of parental training. The therapy for children followed 10 stages including: awareness training; improving motor control; modifying style of planning; cognitive and behavioral restructuring; and relapse prevention. Thirteen children were recruited as consecutive referrals from the general population, and seven cases completed therapy and posttreatment measures. Overall results showed a significant decrease in symptom severity as measured by the YGTSS and the TSGS. However, there was a discrepancy between parent and child rating, with some children perceiving an increase in tics, possibly due to improvement of awareness along therapy. They were also individual changes on adaptive aspects of behavior as measured with the BASC-2, and there was variability among children. All children maintained or improved self-esteem posttreatment. The results confirm the conclusion of a previous pilot study, which contributed to the adaptation of the adult therapy. In summary, the Facotik therapy reduced tics in children. These results underline that addressing processes underlying tics may complement approaches that target tics specifically. PMID:27563292

The Effect of a New Therapy for Children with Tics Targeting Underlying Cognitive, Behavioral, and Physiological Processes.

PubMed

Leclerc, Julie B; O'Connor, Kieron P; J-Nolin, Gabrielle; Valois, Philippe; Lavoie, Marc E

2016-01-01

Tourette disorder (TD) is characterized by motor and vocal tics, and children with TD tend to present a lower quality of life than neurotypical children. This study applied a manualized treatment for childhood tics disorder, Facotik, to a consecutive case series of children aged 8-12 years. The Facotik therapy was adapted from the adult cognitive and psychophysiological program validated on a range of subtypes of tics. This approach aims to modify the cognitive-behavioral and physiological processes against which the tic occurs, rather than only addressing the tic behavior. The Facotik therapy lasted 12-14 weeks. Each week 90-min session contained 20 min of parental training. The therapy for children followed 10 stages including: awareness training; improving motor control; modifying style of planning; cognitive and behavioral restructuring; and relapse prevention. Thirteen children were recruited as consecutive referrals from the general population, and seven cases completed therapy and posttreatment measures. Overall results showed a significant decrease in symptom severity as measured by the YGTSS and the TSGS. However, there was a discrepancy between parent and child rating, with some children perceiving an increase in tics, possibly due to improvement of awareness along therapy. They were also individual changes on adaptive aspects of behavior as measured with the BASC-2, and there was variability among children. All children maintained or improved self-esteem posttreatment. The results confirm the conclusion of a previous pilot study, which contributed to the adaptation of the adult therapy. In summary, the Facotik therapy reduced tics in children. These results underline that addressing processes underlying tics may complement approaches that target tics specifically.

A Multiple-Plasticity Spiking Neural Network Embedded in a Closed-Loop Control System to Model Cerebellar Pathologies.

PubMed

Geminiani, Alice; Casellato, Claudia; Antonietti, Alberto; D'Angelo, Egidio; Pedrocchi, Alessandra

2018-06-01

The cerebellum plays a crucial role in sensorimotor control and cerebellar disorders compromise adaptation and learning of motor responses. However, the link between alterations at network level and cerebellar dysfunction is still unclear. In principle, this understanding would benefit of the development of an artificial system embedding the salient neuronal and plastic properties of the cerebellum and operating in closed-loop. To this aim, we have exploited a realistic spiking computational model of the cerebellum to analyze the network correlates of cerebellar impairment. The model was modified to reproduce three different damages of the cerebellar cortex: (i) a loss of the main output neurons (Purkinje Cells), (ii) a lesion to the main cerebellar afferents (Mossy Fibers), and (iii) a damage to a major mechanism of synaptic plasticity (Long Term Depression). The modified network models were challenged with an Eye-Blink Classical Conditioning test, a standard learning paradigm used to evaluate cerebellar impairment, in which the outcome was compared to reference results obtained in human or animal experiments. In all cases, the model reproduced the partial and delayed conditioning typical of the pathologies, indicating that an intact cerebellar cortex functionality is required to accelerate learning by transferring acquired information to the cerebellar nuclei. Interestingly, depending on the type of lesion, the redistribution of synaptic plasticity and response timing varied greatly generating specific adaptation patterns. Thus, not only the present work extends the generalization capabilities of the cerebellar spiking model to pathological cases, but also predicts how changes at the neuronal level are distributed across the network, making it usable to infer cerebellar circuit alterations occurring in cerebellar pathologies.

Adaptive Controller Adaptation Time and Available Control Authority Effects on Piloting

NASA Technical Reports Server (NTRS)

Trujillo, Anna; Gregory, Irene

2013-01-01

Adaptive control is considered for highly uncertain, and potentially unpredictable, flight dynamics characteristic of adverse conditions. This experiment looked at how adaptive controller adaptation time to recover nominal aircraft dynamics affects pilots and how pilots want information about available control authority transmitted. Results indicate that an adaptive controller that takes three seconds to adapt helped pilots when looking at lateral and longitudinal errors. The controllability ratings improved with the adaptive controller, again the most for the three seconds adaptation time while workload decreased with the adaptive controller. The effects of the displays showing the percentage amount of available safe flight envelope used in the maneuver were dominated by the adaptation time. With the displays, the altitude error increased, controllability slightly decreased, and mental demand increased. Therefore, the displays did require some of the subjects resources but these negatives may be outweighed by pilots having more situation awareness of their aircraft.

Static aeroelastic behavior of an adaptive laminated piezoelectric composite wing

NASA Technical Reports Server (NTRS)

Weisshaar, T. A.; Ehlers, S. M.

1990-01-01

The effect of using an adaptive material to modify the static aeroelastic behavior of a uniform wing is examined. The wing structure is idealized as a laminated sandwich structure with piezoelectric layers in the upper and lower skins. A feedback system that senses the wing root loads applies a constant electric field to the piezoelectric actuator. Modification of pure torsional deformaton behavior and pure bending deformation are investigated, as is the case of an anisotropic composite swept wing. The use of piezoelectric actuators to create an adaptive structure is found to alter static aeroelastic behavior in that the proper choice of the feedback gain can increase or decrease the aeroelastic divergence speed. This concept also may be used to actively change the lift effectiveness of a wing. The ability to modify static aeroelastic behavior is limited by physical limitations of the piezoelectric material and the manner in which it is integrated into the parent structure.

[Surgeons training: today as always?].

PubMed

Jesus, Lisieux Eyer de

2009-12-01

This paper proposes to discuss the training methodologies for young surgeons, considering the modern needs, by discussing their expectations and the reality of the surgeons' job market nowadays. Scientific and technological novelties, the huge amount of information imposed daily, managerial interventions and cost issues modified radically the activities of the surgeons, especially if compared to classical conceptions. Recent re-readings of the classical ethical postulates demand a new behavior of the doctors concerning the patients and the society per se. Contemporaneous social culture bring about individual expectations concerning quality of life and professional perspective issues. It becomes necessary to modify the training methods for surgeons to make them adequate to the need of continuous learning and adaptation to new technological instruments. They also should adapt to social interactions with the patients and the other health professionals that fit nowadays expectations. Those structural adaptations are fundamental to maintain the interest of the new professionals in the area of surgery.

Identification of a motor to auditory pathway important for vocal learning

PubMed Central

Roberts, Todd F.; Hisey, Erin; Tanaka, Masashi; Kearney, Matthew; Chattree, Gaurav; Yang, Cindy F.; Shah, Nirao M.; Mooney, Richard

2017-01-01

Summary Learning to vocalize depends on the ability to adaptively modify the temporal and spectral features of vocal elements. Neurons that convey motor-related signals to the auditory system are theorized to facilitate vocal learning, but the identity and function of such neurons remain unknown. Here we identify a previously unknown neuron type in the songbird brain that transmits vocal motor signals to the auditory cortex. Genetically ablating these neurons in juveniles disrupted their ability to imitate features of an adult tutor’s song. Ablating these neurons in adults had little effect on previously learned songs, but interfered with their ability to adaptively modify the duration of vocal elements and largely prevented the degradation of song’s temporal features normally caused by deafening. These findings identify a motor to auditory circuit essential to vocal imitation and to the adaptive modification of vocal timing. PMID:28504672

Resilience, Integrity and Ecosystem Dynamics: Bridging Ecosystem Theory and Management

NASA Astrophysics Data System (ADS)

Müller, Felix; Burkhard, Benjamin; Kroll, Franziska

In this paper different approaches to elucidate ecosystem dynamics are described, illustrated and interrelated. Ecosystem development is distinguished into two separate sequences, a complexifying phase which is characterized by orientor optimization and a destruction based phase which follows disturbances. The two developmental pathways are integrated in a modified illustration of the "adaptive cycle". Based on these fundamentals, the recent definitions of resilience, adaptability and vulnerability are discussed and a modified comprehension is proposed. Thereafter, two case studies about wetland dynamics are presented to demonstrate both, the consequences of disturbance and the potential of ecosystem recovery. In both examples ecosystem integrity is used as a key indicator variable. Based on the presented results the relativity and the normative loading of resilience quantification is worked out. The paper ends with the suggestion that the features of adaptability could be used as an integrative guideline for the analysis of ecosystem dynamics and as a well-suited concept for ecosystem management.

An Optimal Control Modification to Model-Reference Adaptive Control for Fast Adaptation

NASA Technical Reports Server (NTRS)

Nguyen, Nhan T.; Krishnakumar, Kalmanje; Boskovic, Jovan

2008-01-01

This paper presents a method that can achieve fast adaptation for a class of model-reference adaptive control. It is well-known that standard model-reference adaptive control exhibits high-gain control behaviors when a large adaptive gain is used to achieve fast adaptation in order to reduce tracking error rapidly. High gain control creates high-frequency oscillations that can excite unmodeled dynamics and can lead to instability. The fast adaptation approach is based on the minimization of the squares of the tracking error, which is formulated as an optimal control problem. The necessary condition of optimality is used to derive an adaptive law using the gradient method. This adaptive law is shown to result in uniform boundedness of the tracking error by means of the Lyapunov s direct method. Furthermore, this adaptive law allows a large adaptive gain to be used without causing undesired high-gain control effects. The method is shown to be more robust than standard model-reference adaptive control. Simulations demonstrate the effectiveness of the proposed method.

Heuristics to Evaluate Interactive Systems for Children with Autism Spectrum Disorder (ASD)

PubMed Central

Khowaja, Kamran; Salim, Siti Salwah

2015-01-01

In this paper, we adapted and expanded a set of guidelines, also known as heuristics, to evaluate the usability of software to now be appropriate for software aimed at children with autism spectrum disorder (ASD). We started from the heuristics developed by Nielsen in 1990 and developed a modified set of 15 heuristics. The first 5 heuristics of this set are the same as those of the original Nielsen set, the next 5 heuristics are improved versions of Nielsen's, whereas the last 5 heuristics are new. We present two evaluation studies of our new heuristics. In the first, two groups compared Nielsen’s set with the modified set of heuristics, with each group evaluating two interactive systems. The Nielsen’s heuristics were assigned to the control group while the experimental group was given the modified set of heuristics, and a statistical analysis was conducted to determine the effectiveness of the modified set, the contribution of 5 new heuristics and the impact of 5 improved heuristics. The results show that the modified set is significantly more effective than the original, and we found a significant difference between the five improved heuristics and their corresponding heuristics in the original set. The five new heuristics are effective in problem identification using the modified set. The second study was conducted using a system which was developed to ascertain if the modified set was effective at identifying usability problems that could be fixed before the release of software. The post-study analysis revealed that the majority of the usability problems identified by the experts were fixed in the updated version of the system. PMID:26196385

Robotic intelligence kernel

DOEpatents

Bruemmer, David J [Idaho Falls, ID

2009-11-17

A robot platform includes perceptors, locomotors, and a system controller. The system controller executes a robot intelligence kernel (RIK) that includes a multi-level architecture and a dynamic autonomy structure. The multi-level architecture includes a robot behavior level for defining robot behaviors, that incorporate robot attributes and a cognitive level for defining conduct modules that blend an adaptive interaction between predefined decision functions and the robot behaviors. The dynamic autonomy structure is configured for modifying a transaction capacity between an operator intervention and a robot initiative and may include multiple levels with at least a teleoperation mode configured to maximize the operator intervention and minimize the robot initiative and an autonomous mode configured to minimize the operator intervention and maximize the robot initiative. Within the RIK at least the cognitive level includes the dynamic autonomy structure.

Two-Phase Item Selection Procedure for Flexible Content Balancing in CAT

ERIC Educational Resources Information Center

Cheng, Ying; Chang, Hua-Hua; Yi, Qing

2007-01-01

Content balancing is an important issue in the design and implementation of computerized adaptive testing (CAT). Content-balancing techniques that have been applied in fixed content balancing, where the number of items from each content area is fixed, include constrained CAT (CCAT), the modified multinomial model (MMM), modified constrained CAT…

An Experimental Evaluation of Generalized Predictive Control for Tiltrotor Aeroelastic Stability Augmentation in Airplane Mode of Flight

NASA Technical Reports Server (NTRS)

Kvaternik, Raymond G.; Piatak, David J.; Nixon, Mark W.; Langston, Chester W.; Singleton, Jeffrey D.; Bennett, Richard L.; Brown, Ross K.

2001-01-01

The results of a joint NASA/Army/Bell Helicopter Textron wind-tunnel test to assess the potential of Generalized Predictive Control (GPC) for actively controlling the swashplate of tiltrotor aircraft to enhance aeroelastic stability in the airplane mode of flight are presented. GPC is an adaptive time-domain predictive control method that uses a linear difference equation to describe the input-output relationship of the system and to design the controller. The test was conducted in the Langley Transonic Dynamics Tunnel using an unpowered 1/5-scale semispan aeroelastic model of the V-22 that was modified to incorporate a GPC-based multi-input multi-output control algorithm to individually control each of the three swashplate actuators. Wing responses were used for feedback. The GPC-based control system was highly effective in increasing the stability of the critical wing mode for all of the conditions tested, without measurable degradation of the damping in the other modes. The algorithm was also robust with respect to its performance in adjusting to rapid changes in both the rotor speed and the tunnel airspeed.

Boys' serotonin transporter genotype affects maternal behavior through self-control: a case of evocative gene-environment correlation.

PubMed

Pener-Tessler, Roni; Avinun, Reut; Uzefovsky, Florina; Edelman, Shany; Ebstein, Richard P; Knafo, Ariel

2013-02-01

Self-control, involving processes such as delaying gratification, concentrating, planning, following instructions, and adapting emotions and behavior to situational requirements and social norms, may have a profound impact on children's adjustment. The importance of self-control suggests that parents are likely to modify their parenting based on children's ability for self-control. We study the effect of children's self-control, a trait partially molded by genetics, on their mothers' parenting, a process of evocative gene-environment correlation. Israeli 3.5-year-old twins (N = 320) participated in a lab session in which their mothers' parenting was observed. DNA was available from most children (N = 228). Mothers described children's self-control in a questionnaire. Boys were lower in self-control and received less positive parenting from their mothers, in comparison with girls. For boys, and not for girls, the serotonin transporter linked polymorphic region gene predicted mothers' levels of positive parenting, an effect mediated by boys' self-control. The implications of this evocative gene-environment correlation and the observed sex differences are discussed.

Power-Smoothing Scheme of a DFIG Using the Adaptive Gain Depending on the Rotor Speed and Frequency Deviation

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

Lee, Hyewon; Hwang, Min; Muljadi, Eduard

In an electric power grid that has a high penetration level of wind, the power fluctuation of a large-scale wind power plant (WPP) caused by varying wind speeds deteriorates the system frequency regulation. This paper proposes a power-smoothing scheme of a doubly-fed induction generator (DFIG) that significantly mitigates the system frequency fluctuation while preventing over-deceleration of the rotor speed. The proposed scheme employs an additional control loop relying on the system frequency deviation that operates in combination with the maximum power point tracking control loop. To improve the power-smoothing capability while preventing over-deceleration of the rotor speed, the gain ofmore » the additional loop is modified with the rotor speed and frequency deviation. The gain is set to be high if the rotor speed and/or frequency deviation is large. In conclusion, the simulation results based on the IEEE 14-bus system clearly demonstrate that the proposed scheme significantly lessens the output power fluctuation of a WPP under various scenarios by modifying the gain with the rotor speed and frequency deviation, and thereby it can regulate the frequency deviation within a narrow range.« less

Power-Smoothing Scheme of a DFIG Using the Adaptive Gain Depending on the Rotor Speed and Frequency Deviation

DOE PAGES

Lee, Hyewon; Hwang, Min; Muljadi, Eduard; ...

2017-04-18

In an electric power grid that has a high penetration level of wind, the power fluctuation of a large-scale wind power plant (WPP) caused by varying wind speeds deteriorates the system frequency regulation. This paper proposes a power-smoothing scheme of a doubly-fed induction generator (DFIG) that significantly mitigates the system frequency fluctuation while preventing over-deceleration of the rotor speed. The proposed scheme employs an additional control loop relying on the system frequency deviation that operates in combination with the maximum power point tracking control loop. To improve the power-smoothing capability while preventing over-deceleration of the rotor speed, the gain ofmore » the additional loop is modified with the rotor speed and frequency deviation. The gain is set to be high if the rotor speed and/or frequency deviation is large. In conclusion, the simulation results based on the IEEE 14-bus system clearly demonstrate that the proposed scheme significantly lessens the output power fluctuation of a WPP under various scenarios by modifying the gain with the rotor speed and frequency deviation, and thereby it can regulate the frequency deviation within a narrow range.« less

Optics Program Modified for Multithreaded Parallel Computing

NASA Technical Reports Server (NTRS)

Lou, John; Bedding, Dave; Basinger, Scott

2006-01-01

A powerful high-performance computer program for simulating and analyzing adaptive and controlled optical systems has been developed by modifying the serial version of the Modeling and Analysis for Controlled Optical Systems (MACOS) program to impart capabilities for multithreaded parallel processing on computing systems ranging from supercomputers down to Symmetric Multiprocessing (SMP) personal computers. The modifications included the incorporation of OpenMP, a portable and widely supported application interface software, that can be used to explicitly add multithreaded parallelism to an application program under a shared-memory programming model. OpenMP was applied to parallelize ray-tracing calculations, one of the major computing components in MACOS. Multithreading is also used in the diffraction propagation of light in MACOS based on pthreads [POSIX Thread, (where "POSIX" signifies a portable operating system for UNIX)]. In tests of the parallelized version of MACOS, the speedup in ray-tracing calculations was found to be linear, or proportional to the number of processors, while the speedup in diffraction calculations ranged from 50 to 60 percent, depending on the type and number of processors. The parallelized version of MACOS is portable, and, to the user, its interface is basically the same as that of the original serial version of MACOS.

Partial and total actuator faults accommodation for input-affine nonlinear process plants.

PubMed

Mihankhah, Amin; Salmasi, Farzad R; Salahshoor, Karim

2013-05-01

In this paper, a new fault-tolerant control system is proposed for input-affine nonlinear plants based on Model Reference Adaptive System (MRAS) structure. The proposed method has the capability to accommodate both partial and total actuator failures along with bounded external disturbances. In this methodology, the conventional MRAS control law is modified by augmenting two compensating terms. One of these terms is added to eliminate the nonlinear dynamic, while the other is reinforced to compensate the distractive effects of the total actuator faults and external disturbances. In addition, no Fault Detection and Diagnosis (FDD) unit is needed in the proposed method. Moreover, the control structure has good robustness capability against the parameter variation. The performance of this scheme is evaluated using a CSTR system and the results were satisfactory. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

Viral Evasion and Manipulation of Host RNA Quality Control Pathways

PubMed Central

2016-01-01

Viruses have evolved diverse strategies to maximize the functional and coding capacities of their genetic material. Individual viral RNAs are often used as substrates for both replication and translation and can contain multiple, sometimes overlapping open reading frames. Further, viral RNAs engage in a wide variety of interactions with both host and viral proteins to modify the activities of important cellular factors and direct their own trafficking, packaging, localization, stability, and translation. However, adaptations increasing the information density of small viral genomes can have unintended consequences. In particular, viral RNAs have developed features that mark them as potential targets of host RNA quality control pathways. This minireview focuses on ways in which viral RNAs run afoul of the cellular mRNA quality control and decay machinery, as well as on strategies developed by viruses to circumvent or exploit cellular mRNA surveillance. PMID:27226372

Viral Evasion and Manipulation of Host RNA Quality Control Pathways.

PubMed

Hogg, J Robert

2016-08-15

Viruses have evolved diverse strategies to maximize the functional and coding capacities of their genetic material. Individual viral RNAs are often used as substrates for both replication and translation and can contain multiple, sometimes overlapping open reading frames. Further, viral RNAs engage in a wide variety of interactions with both host and viral proteins to modify the activities of important cellular factors and direct their own trafficking, packaging, localization, stability, and translation. However, adaptations increasing the information density of small viral genomes can have unintended consequences. In particular, viral RNAs have developed features that mark them as potential targets of host RNA quality control pathways. This minireview focuses on ways in which viral RNAs run afoul of the cellular mRNA quality control and decay machinery, as well as on strategies developed by viruses to circumvent or exploit cellular mRNA surveillance. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Randomized Control Trial of COMPASS for Improving Transition Outcomes of Students with Autism Spectrum Disorder.

PubMed

Ruble, Lisa A; McGrew, John H; Toland, Michael; Dalrymple, Nancy; Adams, Medina; Snell-Rood, Claire

2018-06-01

The postsecondary outcomes of individuals with autism spectrum disorder (ASD) are significantly worse than peers with other disabilities. One problem is the lack of empirically-supported transition planning interventions to guide services and help produce better outcomes. We applied an implementation science approach to adapt and modify an evidence-based consultation intervention originally tested with young children called the Collaborative Model for Promoting Competence and Success (COMPASS; Ruble et al., The collaborative model for promoting competence and success for students with ASD. Springer, New York, 2012a) and evaluate it for efficacy in a randomized controlled trial for transition-age youth. Results replicated findings with younger students with ASD that IEP outcomes were higher for COMPASS compared to the placebo control group (d = 2.1). Consultant fidelity was high and teacher adherence improved over time, replicating the importance of ongoing teacher coaching.

Cross-cultural adaptation and reproducibility of the Brazilian-Portuguese version of the modified FRESNO Test to evaluate the competence in evidence based practice by physical therapists

PubMed Central

Silva, Anderson M.; Costa, Lucíola C. M.; Comper, Maria L.; Padula, Rosimeire S.

2016-01-01

BACKGROUND: The Modified Fresno Test was developed to assess knowledge and skills of both physical therapy (PT) professionals and students to use evidence-based practice (EBP). OBJECTIVES: To translate the Modified Fresno Test into Brazilian-Portuguese and to evaluate the test's reproducibility. METHOD: The first step consisted of adapting the instrument into the Brazilian-Portuguese language. Then, a total of 57 participants, including PT students, PT professors and PT practitioners, completed the translated instrument. The responses from the participants were used to evaluate reproducibility of the translated instrument. Internal consistency was calculated using the Cronbach's alpha. Reliability was calculated using the intraclass correlation coefficient (ICC) for continuous variables, and the Kappa coefficient (K) for categorical variables. The agreement was assessed using the standard error of the measurement (SEM). RESULTS: The cross-cultural adaptation process was appropriate, providing an adequate Brazilian-Portuguese version of the instrument. The internal consistency was good (α=0.769). The reliability for inter- and intra-rater assessment were ICC=0.89 (95% CI 0.82 to 0.93); for evaluator 1 was ICC=0.85 (95% CI 0.57 to 0.93); and for evaluator 2 was ICC=0.98 (95% CI 0.97 to 0.99). The SEM was 13.04 points for inter-rater assessment, 12.57 points for rater 1 and 4.59 points for rater 2. CONCLUSION: The Brazilian-Portuguese language version of the Modified Fresno Test showed satisfactory results in terms of reproducibility. The Modified Fresno Test will allow physical therapy professionals and students to be evaluated on the use of understanding EBP. PMID:26786079

Cross-cultural adaptation and reproducibility of the Brazilian-Portuguese version of the modified FRESNO Test to evaluate the competence in evidence based practice by physical therapists.

PubMed

Silva, Anderson M; Costa, Lucíola C M; Comper, Maria L; Padula, Rosimeire S

2016-01-01

The Modified Fresno Test was developed to assess knowledge and skills of both physical therapy (PT) professionals and students to use evidence-based practice (EBP). To translate the Modified Fresno Test into Brazilian-Portuguese and to evaluate the test's reproducibility. The first step consisted of adapting the instrument into the Brazilian-Portuguese language. Then, a total of 57 participants, including PT students, PT professors and PT practitioners, completed the translated instrument. The responses from the participants were used to evaluate reproducibility of the translated instrument. Internal consistency was calculated using the Cronbach's alpha. Reliability was calculated using the intraclass correlation coefficient (ICC) for continuous variables, and the Kappa coefficient (K) for categorical variables. The agreement was assessed using the standard error of the measurement (SEM). The cross-cultural adaptation process was appropriate, providing an adequate Brazilian-Portuguese version of the instrument. The internal consistency was good (α=0.769). The reliability for inter- and intra-rater assessment were ICC=0.89 (95% CI 0.82 to 0.93); for evaluator 1 was ICC=0.85 (95% CI 0.57 to 0.93); and for evaluator 2 was ICC=0.98 (95% CI 0.97 to 0.99). The SEM was 13.04 points for inter-rater assessment, 12.57 points for rater 1 and 4.59 points for rater 2. The Brazilian-Portuguese language version of the Modified Fresno Test showed satisfactory results in terms of reproducibility. The Modified Fresno Test will allow physical therapy professionals and students to be evaluated on the use of understanding EBP.

Adaptive nonlocal means filtering based on local noise level for CT denoising

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

Li, Zhoubo; Trzasko, Joshua D.; Lake, David S.

2014-01-15

Purpose: To develop and evaluate an image-domain noise reduction method based on a modified nonlocal means (NLM) algorithm that is adaptive to local noise level of CT images and to implement this method in a time frame consistent with clinical workflow. Methods: A computationally efficient technique for local noise estimation directly from CT images was developed. A forward projection, based on a 2D fan-beam approximation, was used to generate the projection data, with a noise model incorporating the effects of the bowtie filter and automatic exposure control. The noise propagation from projection data to images was analytically derived. The analyticalmore » noise map was validated using repeated scans of a phantom. A 3D NLM denoising algorithm was modified to adapt its denoising strength locally based on this noise map. The performance of this adaptive NLM filter was evaluated in phantom studies in terms of in-plane and cross-plane high-contrast spatial resolution, noise power spectrum (NPS), subjective low-contrast spatial resolution using the American College of Radiology (ACR) accreditation phantom, and objective low-contrast spatial resolution using a channelized Hotelling model observer (CHO). Graphical processing units (GPU) implementation of this noise map calculation and the adaptive NLM filtering were developed to meet demands of clinical workflow. Adaptive NLM was piloted on lower dose scans in clinical practice. Results: The local noise level estimation matches the noise distribution determined from multiple repetitive scans of a phantom, demonstrated by small variations in the ratio map between the analytical noise map and the one calculated from repeated scans. The phantom studies demonstrated that the adaptive NLM filter can reduce noise substantially without degrading the high-contrast spatial resolution, as illustrated by modulation transfer function and slice sensitivity profile results. The NPS results show that adaptive NLM denoising preserves the shape and peak frequency of the noise power spectrum better than commercial smoothing kernels, and indicate that the spatial resolution at low contrast levels is not significantly degraded. Both the subjective evaluation using the ACR phantom and the objective evaluation on a low-contrast detection task using a CHO model observer demonstrate an improvement on low-contrast performance. The GPU implementation can process and transfer 300 slice images within 5 min. On patient data, the adaptive NLM algorithm provides more effective denoising of CT data throughout a volume than standard NLM, and may allow significant lowering of radiation dose. After a two week pilot study of lower dose CT urography and CT enterography exams, both GI and GU radiology groups elected to proceed with permanent implementation of adaptive NLM in their GI and GU CT practices. Conclusions: This work describes and validates a computationally efficient technique for noise map estimation directly from CT images, and an adaptive NLM filtering based on this noise map, on phantom and patient data. Both the noise map calculation and the adaptive NLM filtering can be performed in times that allow integration with clinical workflow. The adaptive NLM algorithm provides effective denoising of CT data throughout a volume, and may allow significant lowering of radiation dose.« less

Adaptive Flight Control for Aircraft Safety Enhancements

NASA Technical Reports Server (NTRS)

Nguyen, Nhan T.; Gregory, Irene M.; Joshi, Suresh M.

2008-01-01

This poster presents the current adaptive control research being conducted at NASA ARC and LaRC in support of the Integrated Resilient Aircraft Control (IRAC) project. The technique "Approximate Stability Margin Analysis of Hybrid Direct-Indirect Adaptive Control" has been developed at NASA ARC to address the needs for stability margin metrics for adaptive control that potentially enables future V&V of adaptive systems. The technique "Direct Adaptive Control With Unknown Actuator Failures" is developed at NASA LaRC to deal with unknown actuator failures. The technique "Adaptive Control with Adaptive Pilot Element" is being researched at NASA LaRC to investigate the effects of pilot interactions with adaptive flight control that can have implications of stability and performance.

DIY Adapted Repurposed Tool (ART) Kit-A Recipe for Success

ERIC Educational Resources Information Center

Schoonover, Judith; Schwind, Deborah B.

2018-01-01

Every individual should be provided with opportunities to self-express through participation in art activities. In order to provide independent exploration and creativity during art, it may be necessary to adapt art tools, modify how the activity is accomplished, and examine the environment to determine the best methods to provide access. Simple…

Item Pocket Method to Allow Response Review and Change in Computerized Adaptive Testing

ERIC Educational Resources Information Center

Han, Kyung T.

2013-01-01

Most computerized adaptive testing (CAT) programs do not allow test takers to review and change their responses because it could seriously deteriorate the efficiency of measurement and make tests vulnerable to manipulative test-taking strategies. Several modified testing methods have been developed that provide restricted review options while…

Quality protein maize germplasm characterized for amino acid profiles and endosperm opacity

USDA-ARS?s Scientific Manuscript database

Quality protein maize (QPM) is improved over normal maize in grain concentrations of the essential amino acids lysine and tryptophan. QPM has a long history as tropical adapted germplasm but little effort has been made in temperate and sub-tropical adaptation and it is unknown if different modifier ...

Adapting and Modifying Toys for Children with Special Needs.

ERIC Educational Resources Information Center

Simpson, Cynthia G.; Lynch, Sharon A.

Many caregivers doubt their ability to provide appropriate play experiences for children with special needs included in their program because some children with disabilities may not have the ability to interact and manipulate toys in a meaningful way. This paper provides guidance in appropriately adapting toys and the play situation to allow many…

Conflict adaptation in prefrontal cortex: now you see it, now you don't.

PubMed

Kim, Chobok; Johnson, Nathan F; Gold, Brian T

2014-01-01

Daily life requires people to monitor and resolve conflict arising from distracting information irrelevant to current goals. The highly influential conflict monitoring theory (CMT) holds that the anterior cingulate cortex (ACC) detects conflict and subsequently triggers the dorsolateral prefrontal cortex (DLPFC) to regulate that conflict. Multiple lines of evidence have provided support for CMT. For example, performance is faster on incongruent trials that follow other incongruent trials (iI), and is accompanied by reduced ACC and increased DLPFC activation (the conflict adaptation effect). In this fMRI study, we explored whether ACC-DLPFC conflict signaling can result in behavioral adjustments beyond on-line contexts. Participants completed a modified version of the Stroop conflict adaptation paradigm which tested for conflict adaptation effects on the current (N) trial associated with not only the immediately preceding (N - 1) trial, but also 2-back (N - 2) trials. Results demonstrated evidence for direct relationships between ACC activity on N - 2 trials and both N trial DLPFC activity and behavioral adjustment when intervening trials were congruent (i.e., icI). In contrast, when N - 1 trials were incongruent (i.e., iiI), ACC-DLPFC signaling failed and conflict adaptation was absent. These results provide new evidence demonstrating that the conflict monitor-controller maintains previously experienced conflict in the service of subsequent behavioral adjustment. However, the processing of multiple, temporally proximal conflict signals takes a toll on the working memory (WM) system, which appears to require resetting in order to adapt our behavior to frequently changing environmental demands. Copyright © 2013 Elsevier Ltd. All rights reserved.

Animal thermoregulation: a review of insulation, physiology and behaviour relevant to temperature control in buildings.

PubMed

McCafferty, D J; Pandraud, G; Gilles, J; Fabra-Puchol, M; Henry, P-Y

2017-12-28

Birds and mammals have evolved many thermal adaptations that are relevant to the bioinspired design of temperature control systems and energy management in buildings. Similar to many buildings, endothermic animals generate internal metabolic heat, are well insulated, regulate their temperature within set limits, modify microclimate and adjust thermal exchange with their environment. We review the major components of animal thermoregulation in endothermic birds and mammals that are pertinent to building engineering, in a world where climate is changing and reduction in energy use is needed. In animals, adjustment of insulation together with physiological and behavioural responses to changing environmental conditions fine-tune spatial and temporal regulation of body temperature, while also minimizing energy expenditure. These biological adaptations are characteristically flexible, allowing animals to alter their body temperatures to hourly, daily, or annual demands for energy. They exemplify how buildings could become more thermally reactive to meteorological fluctuations, capitalising on dynamic thermal materials and system properties. Based on this synthesis, we suggest that heat transfer modelling could be used to simulate these flexible biomimetic features and assess their success in reducing energy costs while maintaining thermal comfort for given building types.

Taylor bubbles at high viscosity ratios: experiments and numerical simulations

NASA Astrophysics Data System (ADS)

Hewakandamby, Buddhika; Hasan, Abbas; Azzopardi, Barry; Xie, Zhihua; Pain, Chris; Matar, Omar

2015-11-01

The Taylor bubble is a single long bubble which nearly fills the entire cross section of a liquid-filled circular tube, often occurring in gas-liquid slug flows in many industrial applications, particularly oil and gas production. The objective of this study is to investigate the fluid dynamics of three-dimensional Taylor bubble rising in highly viscous silicone oil in a vertical pipe. An adaptive unstructured mesh modelling framework is adopted here which can modify and adapt anisotropic unstructured meshes to better represent the underlying physics of bubble rising and reduce computational effort without sacrificing accuracy. The numerical framework consists of a mixed control volume and finite element formulation, a `volume of fluid'-type method for the interface-capturing based on a compressive control volume advection method, and a force-balanced algorithm for the surface tension implementation. Experimental results for the Taylor bubble shape and rise velocity are presented, together with numerical results for the dynamics of the bubbles. A comparison of the simulation predictions with experimental data available in the literature is also presented to demonstrate the capabilities of our numerical method. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

Wii Fit® training vs. Adapted Physical Activities: which one is the most appropriate to improve the balance of independent senior subjects? A randomized controlled study.

PubMed

Toulotte, Claire; Toursel, Cindy; Olivier, Nicolas

2012-09-01

To compare the effectiveness of three protocols (Adapted Physical Activities, Wii Fit(®), Adapted Physical Activities + Wii Fit(®)) on the balance of independent senior subjects. Case comparison study. Healthy elderly subjects living in independent community dwellings. Thirty-six subjects, average age 75.09 ± 10.26 years, took part in this study, and were randomly assigned to one of the four experimental groups: G1 followed an Adapted Physical Activities training programme, while the second group (G2) participated in Wii Fit(®) training and the third one (G3) combined both methods. There was no training for the fourth group (G4). All subjects trained once a week (1 hour) for 20 weeks and were assessed before and after treatment. The Tinetti test, unipedal tests and the Wii Fit(®) tests. After training, the scores in the Tinetti test decreased significantly (P < 0.05) for G1, G2 and G3 respectively in static conditions and for G1 and G3 in dynamic conditions. After training, the performance in the unipedal tests decreased significantly (P < 0.05) for G1 and G3. The position of the centre of gravity was modified significantly (P < 0.05) for G2 and G3. After 20 training sessions, G1 (Adapted Physical Activities), G2 (Wii Fit(®)) and G3 (Adapted Physical Activities and Wii Fit(®)) improved their balance. In addition, G1 and G3 increased their dynamic balance. The findings suggest that Adapted Physical Activities training limits the decline in sensorial functions in the elderly.

Verification and Validation Challenges for Adaptive Flight Control of Complex Autonomous Systems

NASA Technical Reports Server (NTRS)

Nguyen, Nhan T.

2018-01-01

Autonomy of aerospace systems requires the ability for flight control systems to be able to adapt to complex uncertain dynamic environment. In spite of the five decades of research in adaptive control, the fact still remains that currently no adaptive control system has ever been deployed on any safety-critical or human-rated production systems such as passenger transport aircraft. The problem lies in the difficulty with the certification of adaptive control systems since existing certification methods cannot readily be used for nonlinear adaptive control systems. Research to address the notion of metrics for adaptive control began to appear in the recent years. These metrics, if accepted, could pave a path towards certification that would potentially lead to the adoption of adaptive control as a future control technology for safety-critical and human-rated production systems. Development of certifiable adaptive control systems represents a major challenge to overcome. Adaptive control systems with learning algorithms will never become part of the future unless it can be proven that they are highly safe and reliable. Rigorous methods for adaptive control software verification and validation must therefore be developed to ensure that adaptive control system software failures will not occur, to verify that the adaptive control system functions as required, to eliminate unintended functionality, and to demonstrate that certification requirements imposed by regulatory bodies such as the Federal Aviation Administration (FAA) can be satisfied. This presentation will discuss some of the technical issues with adaptive flight control and related V&V challenges.

Management and Care of Women With Invasive Cervical Cancer: American Society of Clinical Oncology Resource-Stratified Clinical Practice Guideline

PubMed Central

Chuang, Linus T.; Temin, Sarah; Camacho, Rolando; Dueñas-Gonzalez, Alfonso; Feldman, Sarah; Gultekin, Murat; Gupta, Vandana; Horton, Susan; Jacob, Graciela; Kidd, Elizabeth A.; Lishimpi, Kennedy; Nakisige, Carolyn; Nam, Joo-Hyun; Ngan, Hextan Yuen Sheung; Small, William; Thomas, Gillian; Berek, Jonathan S.

2016-01-01

Purpose To provide evidence-based, resource-stratified global recommendations to clinicians and policymakers on the management and palliative care of women diagnosed with invasive cervical cancer. Methods ASCO convened a multidisciplinary, multinational panel of cancer control, medical and radiation oncology, health economic, obstetric and gynecologic, and palliative care experts to produce recommendations reflecting resource-tiered settings. A systematic review of literature from 1966 to 2015 failed to yield sufficiently strong quality evidence to support basic- and limited-resource setting recommendations; a formal consensus-based process was used to develop recommendations. A modified ADAPTE process was also used to adapt recommendations from existing guidelines. Results Five existing sets of guidelines were identified and reviewed, and adapted recommendations form the evidence base. Eight systematic reviews, along with cost-effectiveness analyses, provided indirect evidence to inform the consensus process, which resulted in agreement of 75% or greater. Recommendations Clinicians and planners should strive to provide access to the most effective evidence-based antitumor and palliative care interventions. If a woman cannot access these within her own or neighboring country or region, she may need to be treated with lower-tier modalities, depending on capacity and resources for surgery, chemotherapy, radiation therapy, and supportive and palliative care. For women with early-stage cervical cancer in basic settings, cone biopsy or extrafascial hysterectomy may be performed. Fertility-sparing procedures or modified radical or radical hysterectomy may be additional options in nonbasic settings. Combinations of surgery, chemotherapy, and radiation therapy (including brachytherapy) should be used for women with stage IB to IVA disease, depending on available resources. Pain control is a vital component of palliative care. Additional information is available at www.asco.org/rs-cervical-cancer-treatment-guideline and www.asco.org/guidelineswiki. It is the view of ASCO that health care providers and health care system decision makers should be guided by the recommendations for the highest stratum of resources available. The guideline is intended to complement but not replace local guidelines. PMID:28717717

Method and apparatus for adaptive force and position control of manipulators

NASA Technical Reports Server (NTRS)

Seraji, Homayoun (Inventor)

1989-01-01

The present invention discloses systematic methods and apparatus for the design of real time controllers. Real-time control employs adaptive force/position by use of feedforward and feedback controllers, with the feedforward controller being the inverse of the linearized model of robot dynamics and containing only proportional-double-derivative terms is disclosed. The feedback controller, of the proportional-integral-derivative type, ensures that manipulator joints follow reference trajectories and the feedback controller achieves robust tracking of step-plus-exponential trajectories, all in real time. The adaptive controller includes adaptive force and position control within a hybrid control architecture. The adaptive controller, for force control, achieves tracking of desired force setpoints, and the adaptive position controller accomplishes tracking of desired position trajectories. Circuits in the adaptive feedback and feedforward controllers are varied by adaptation laws.

Marginal adaptation of CAD-CAM onlays: Influence of preparation design and impression technique.

PubMed

Lima, Fernanda Ferruzzi; Neto, Constantino Fernandes; Rubo, José H; Santos, Gildo Coelho; Moraes Coelho Santos, Maria Jacinta

2018-03-15

Factors that may affect the marginal adaptation of computer-aided design and computer-aided manufacturing (CAD-CAM) restorations include preparation design, impression technique, and CAD-CAM system. The influence of impression technique and preparation design on CAD-CAM partial coverage restorations has not been fully addressed. The purpose of this in vitro study was to investigate the influence of direct and indirect digital impression techniques and 2 preparation designs on the marginal adaptation of CAD-CAM onlays. Two mesio-occlusal buccal onlay preparations with reduction of the mesiobuccal cusp were made: conventional preparation (CP) with a 1.2-mm modified shoulder margin and modified preparation (MP) flat cuspal reduction without shoulder. Virtual models were generated from each preparation by using a digital scanner (BlueCam; Dentsply Sirona) from the plastic teeth (direct digital impression) or from the stone dies (indirect digital impression). Onlays were designed using a CAD-CAM system (CEREC 4.0; Dentsply Sirona), and nanoceramic resin blocks (Lava Ultimate Restorative; 3M ESPE) were milled using the CEREC MCX milling machine. Marginal discrepancy was evaluated using an optical stereomicroscope at ×25 magnification in 18 locations distributed along the margins of the preparation. The data were analyzed by using 3-way ANOVA followed by the Tukey HSD test (α=.05). CP presented a statistically significant reduced average marginal adaptation (59 ±50 μm) than did MP (69 ±58 μm) (P<.001). The Tukey HSD test showed the presence of a significantly larger marginal discrepancy in the mesial and buccal locations of MP when compared with CP. Regarding impression techniques, the buccal location presented the smallest average marginal discrepancy in restorations fabricated with indirect impression when compared with direct impression (42 ±33 μm and 60 ±39 μm) (P<.001). The results showed that conventional preparation with a modified shoulder margin presented improved marginal adaptation compared with modified preparation with flat cuspal reduction. Direct and indirect digital impression techniques produced restorations within a clinically acceptable range; however, the indirect impression technique resulted in the fabrication of restorations with superior marginal adaptation on the buccal location. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Adaptive Flight Control Design with Optimal Control Modification on an F-18 Aircraft Model

NASA Technical Reports Server (NTRS)

Burken, John J.; Nguyen, Nhan T.; Griffin, Brian J.

2010-01-01

In the presence of large uncertainties, a control system needs to be able to adapt rapidly to regain performance. Fast adaptation is referred to as the implementation of adaptive control with a large adaptive gain to reduce the tracking error rapidly; however, a large adaptive gain can lead to high-frequency oscillations which can adversely affect the robustness of an adaptive control law. A new adaptive control modification is presented that can achieve robust adaptation with a large adaptive gain without incurring high-frequency oscillations as with the standard model-reference adaptive control. The modification is based on the minimization of the Y2 norm of the tracking error, which is formulated as an optimal control problem. The optimality condition is used to derive the modification using the gradient method. The optimal control modification results in a stable adaptation and allows a large adaptive gain to be used for better tracking while providing sufficient robustness. A damping term (v) is added in the modification to increase damping as needed. Simulations were conducted on a damaged F-18 aircraft (McDonnell Douglas, now The Boeing Company, Chicago, Illinois) with both the standard baseline dynamic inversion controller and the adaptive optimal control modification technique. The results demonstrate the effectiveness of the proposed modification in tracking a reference model.

Adaptive changes in the angular VOR: duration of gain changes and lack of effect of nodulo-uvulectomy.

PubMed

Yakushin, Sergei B; Bukharina, Svetlana E; Raphan, Theodore; Buttner-Ennever, Jean; Cohen, Bernard

2003-10-01

Alterations in the gain of the vertical angular vestibulo-ocular reflex (VOR) are dependent on the head position in which the gain changes were produced. We determined how long gravity-dependent gain changes last in monkeys after four hours of adaptation, and whether the adaptation is mediated through the nodulus and uvula of the vestibulocerebellum. Vertical VOR gains were adaptively modified by rotation about an interaural axis, in phase or out of phase with the visual surround. Vertical VOR gains were modified with the animals in one of three orientations: upright, left-side down, or right-side down. Monkeys were tested in darkness for up to four days after adaptation using sinusoidal rotation about an interaural axis that was incrementally tilted in 10 degrees steps from vertical to side down positions. Animals were unrestrained in their cages in normal light conditions between tests. Gravity-dependent gain changes lasted for a day or less after adaptation while upright, but persisted for two days or more after on-side adaptation. These data show that gravity-dependent gain changes can last for prolonged periods after only four hours of adaptation in monkeys, as in humans. They also demonstrate that natural head movements made while upright do not provide an adequate stimulus for rapid recovery of vertical VOR gains that were induced on side. In two animals, the nodulus and uvula were surgically ablated. Vertical gravity-dependent gain changes were not significantly different before and after surgery, indicating that the nodulus and uvula do not have a critical role in producing them.

Implementation and dissemination of a transition of care program for rural veterans: a controlled before and after study.

PubMed

Leonard, Chelsea; Lawrence, Emily; McCreight, Marina; Lippmann, Brandi; Kelley, Lynette; Mayberry, Ashlea; Ladebue, Amy; Gilmartin, Heather; Côté, Murray J; Jones, Jacqueline; Rabin, Borsika A; Ho, P Michael; Burke, Robert

2017-10-23

Adapting promising health care interventions to local settings is a critical component in the dissemination and implementation process. The Veterans Health Administration (VHA) rural transitions nurse program (TNP) is a nurse-led, Veteran-centered intervention designed to improve transitional care for rural Veterans funded by VA national offices for dissemination to other VA sites serving a predominantly rural Veteran population. Here, we describe our novel approach to the implementation and evaluation = the TNP. This is a controlled before and after study that assesses both implementation and intervention outcomes. During pre-implementation, we assessed site context using a mixed method approach with data from diverse sources including facility-level quantitative data, key informant and Veteran interviews, observations of the discharge process, and a group brainstorming activity. We used the Practical Robust Implementation and Sustainability Model (PRISM) to inform our inquiries, to integrate data from all sources, and to identify factors that may affect implementation. In the implementation phase, we will use internal and external facilitation, paired with audit and feedback, to encourage appropriate contextual adaptations. We will use a modified Stirman framework to document adaptations. During the evaluation phase, we will measure intervention and implementation outcomes at each site using the RE-AIM framework (Reach, Effectiveness, Adoption, Implementation, and Maintenance). We will conduct a difference-in-differences analysis with propensity-matched Veterans and VA facilities as a control. Our primary intervention outcome is 30-day readmission and Emergency Department visit rates. We will use our findings to develop an implementation toolkit that will inform the larger scale-up of the TNP across the VA. The use of PRISM to inform pre-implementation evaluation and synthesize data from multiple sources, coupled with internal and external facilitation, is a novel approach to engaging sites in adapting interventions while promoting fidelity to the intervention. Our application of PRISM to pre-implementation and midline evaluation, as well as documentation of adaptations, provides an opportunity to identify and address contextual factors that may impede or enhance implementation and sustainability of health interventions and inform dissemination.

I Feel You: The Design and Evaluation of a Domotic Affect-Sensitive Spoken Conversational Agent

PubMed Central

Lutfi, Syaheerah Lebai; Fernández-Martínez, Fernando; Lorenzo-Trueba, Jaime; Barra-Chicote, Roberto; Montero, Juan Manuel

2013-01-01

We describe the work on infusion of emotion into a limited-task autonomous spoken conversational agent situated in the domestic environment, using a need-inspired task-independent emotion model (NEMO). In order to demonstrate the generation of affect through the use of the model, we describe the work of integrating it with a natural-language mixed-initiative HiFi-control spoken conversational agent (SCA). NEMO and the host system communicate externally, removing the need for the Dialog Manager to be modified, as is done in most existing dialog systems, in order to be adaptive. The first part of the paper concerns the integration between NEMO and the host agent. The second part summarizes the work on automatic affect prediction, namely, frustration and contentment, from dialog features, a non-conventional source, in the attempt of moving towards a more user-centric approach. The final part reports the evaluation results obtained from a user study, in which both versions of the agent (non-adaptive and emotionally-adaptive) were compared. The results provide substantial evidences with respect to the benefits of adding emotion in a spoken conversational agent, especially in mitigating users' frustrations and, ultimately, improving their satisfaction. PMID:23945740

Anatomical segregation of different adaptative processes within the vestibulocerebellum of the cat.

PubMed

Torte, M P; Courjon, J H; Flandrin, J M; Magnin, M; Magenes, G

1994-01-01

Bilateral surgical lesions of the flocculus or the nodulo-uvular lobes were performed in the cat. Effects of these lesions on optokinetic and optokinetic afternystagmus OKAN), vestibulo-ocular reflex (VOR), visual suppression, and adaptation and habituation of VOR were studied using an identical experimental protocol. After flocculectomy, all these functions were impaired, except for habituation. Long-term postoperative recordings only revealed a recovery of the suppression of VOR, suggesting a limited contribution of the flocculus to this function. After nodulo-uvulectomy, only habituation and OKAN were modified. When the lesion was restricted to part of the uvula, OKAN duration was decreased. For other lesions involving the uvula together with the nodulus and/or the lobules VII-VIII,OKAN duration was increased. Habituation was lost after destruction of the nodulo-uvular lobes. When this latter structure was damaged, the retention component of habituation was selectively impaired, sparing the acquisition. Additional lesions outside the vestibulocerebellum appeared necessary to suppress the two components. Comparison of results obtained after flocculectomy and after nodulouvulectomy confirms and extends to non-primate species the concept of a "differential control" of adaptation and habituation by distinct vestibulocerebellar structures.

Experimental Validation of L1 Adaptive Control: Rohrs' Counterexample in Flight

NASA Technical Reports Server (NTRS)

Xargay, Enric; Hovakimyan, Naira; Dobrokhodov, Vladimir; Kaminer, Issac; Kitsios, Ioannis; Cao, Chengyu; Gregory, Irene M.; Valavani, Lena

2010-01-01

The paper presents new results on the verification and in-flight validation of an L1 adaptive flight control system, and proposes a general methodology for verification and validation of adaptive flight control algorithms. The proposed framework is based on Rohrs counterexample, a benchmark problem presented in the early 80s to show the limitations of adaptive controllers developed at that time. In this paper, the framework is used to evaluate the performance and robustness characteristics of an L1 adaptive control augmentation loop implemented onboard a small unmanned aerial vehicle. Hardware-in-the-loop simulations and flight test results confirm the ability of the L1 adaptive controller to maintain stability and predictable performance of the closed loop adaptive system in the presence of general (artificially injected) unmodeled dynamics. The results demonstrate the advantages of L1 adaptive control as a verifiable robust adaptive control architecture with the potential of reducing flight control design costs and facilitating the transition of adaptive control into advanced flight control systems.

Adaptive functioning and its associated factors among girl children residing in slum areas of Bhubaneswar, India.

PubMed

Panigrahi, Ansuman; Das, Sai C; Sahoo, Prabhudarsan

2018-01-01

Adaptive functioning develops throughout early childhood, and its limitation is a reflection that the child has developmental or emotional problems or even mental retardation. Little is known about the adaptive functioning or developmental status of slum children. The present cross-sectional study was undertaken during the year 2014 to assess the status of adaptive functioning among girl children aged between 3 and 9 years residing in slum areas of Bhubaneswar and to explore the factors associated with poor adaptive functioning. Stratified multi-stage cluster random sampling technique was used to select the study population; 256 mother-child pairs from 256 households in selected slum areas were studied. Demographic information was collected, and adaptive functioning was assessed using the modified Vineland Social Maturity Scale. Univariate and multivariate analyses was carried out using Statistical Package for Social Sciences (SPSS) version 21. One-fifth (54, 21%) of the girls sampled had poor adaptive functioning, and 44 (17%) had poor cognitive functioning. Multivariate analysis revealed that the age of the child, parents' education, presence of stunting in children and attending school/early childhood centre were strong predictors of adaptive functioning in slum children. One-fifth of girls from slums are developmentally vulnerable; parental education, stunting and early childhood education or exposure to schooling are modifiable factors influencing children's adaptive functioning. Health, education and welfare sectors need to be aware of this so that a multi-pronged approach can be planned to properly address this issue in one of the most disadvantaged sections of the society. © 2017 Paediatrics and Child Health Division (The Royal Australasian College of Physicians).

Composite synchronization of three eccentric rotors driven by induction motors in a vibrating system

NASA Astrophysics Data System (ADS)

Kong, Xiangxi; Chen, Changzheng; Wen, Bangchun

2018-03-01

This paper addresses the problem of composite synchronization of three eccentric rotors (ERs) driven by induction motors in a vibrating system. The composite synchronous motion of three ERs is composed of the controlled synchronous motion of two ERs and the self-synchronous motion of the third ER. Combining an adaptive sliding mode control (ASMC) algorithm with a modified master-slave control structure, the controllers are designed to implement controlled synchronous motion of two ERs with zero phase difference. Based on Lyapunov stability theorem and Barbalat's lemma, the stability of the designed controllers is verified. On basis of controlled synchronization of two ERs, self-synchronization of the third ER is introduced to implement composite synchronous motion of three ERs. The feasibility of the proposed composite synchronization method is analyzed by numerical method. The effects of motor and structure parameters on composite synchronous motion are discussed. Experiments on a vibrating test bench driven by three ERs are operated to validate the effectiveness of the proposed composite synchronization method, including a comparison with self-synchronization method.

Aeroelastic Airworthiness Assesment of the Adaptive Compliant Trailing Edge Flaps

NASA Technical Reports Server (NTRS)

Herrera, Claudia Y.; Spivey, Natalie D.; Lung, Shun-fat; Ervin, Gregory; Flick, Peter

2015-01-01

The Adaptive Compliant Trailing Edge (ACTE) demonstrator is a joint task under the National Aeronautics and Space Administration Environmentally Responsible Aviation Project in partnership with the Air Force Research Laboratory and FlexSys, Inc. (Ann Arbor, Michigan). The project goal is to develop advanced technologies that enable environmentally friendly aircraft, such as adaptive compliant technologies. The ACTE demonstrator flight-test program encompassed replacing the Fowler flaps on the SubsoniC Aircraft Testbed, a modified Gulfstream III (Gulfstream Aerospace, Savannah, Georgia) aircraft, with control surfaces developed by FlexSys. The control surfaces developed by FlexSys are a pair of uniquely-designed unconventional flaps to be used as lifting surfaces during flight-testing to validate their structural effectiveness. The unconventional flaps required a multidisciplinary airworthiness assessment to prove they could withstand the prescribed flight envelope. Several challenges were posed due to the large deflections experienced by the structure, requiring non-linear analysis methods. The aeroelastic assessment necessitated both conventional and extensive testing and analysis methods. A series of ground vibration tests (GVTs) were conducted to provide modal characteristics to validate and update finite element models (FEMs) used for the flutter analyses for a subset of the various flight configurations. Numerous FEMs were developed using data from FlexSys and the ground tests. The flap FEMs were then attached to the aircraft model to generate a combined FEM that could be analyzed for aeroelastic instabilities. The aeroelastic analysis results showed the combined system of aircraft and flaps were predicted to have the required flutter margin to successfully demonstrate the adaptive compliant technology. This paper documents the details of the aeroelastic airworthiness assessment described, including the ground testing and analyses, and subsequent flight-testing performed on the unconventional ACTE flaps.

Effects of different seating equipment on postural control and upper extremity function in children with cerebral palsy.

PubMed

Sahinoğlu, Dilek; Coskun, Gürsoy; Bek, Nilgün

2017-02-01

Adaptive seating supports for cerebral palsy are recommended to develop and maintain optimum posture, and functional use of upper extremities. To compare the effectiveness of different seating adaptations regarding postural alignment and related functions and to investigate the effects of these seating adaptations on different motor levels. Prospective study. A total of 20 children with spastic cerebral palsy (Gross Motor Function Classification System 3-5) were included. Postural control and function (Seated Postural Control Measure, Sitting Assessment Scale) were measured in three different systems: standard chair, adjustable seating system and custom-made orthosis. In results of all participants ungrouped, there was a significant difference in most parameters of both measurement tools in favor of custom-made orthosis and adjustable seating system when compared to standard chair ( p < 0.0017). There was a difference among interventions in most of the Seated Postural Control Measure results in Level 4 when subjects were grouped according to Gross Motor Function Classification System levels. A difference was observed between standard chair and adjustable seating system in foot control, arm control, and total Sitting Assessment Scale scores; and between standard chair and custom-made orthosis in trunk control, arm control, and total Sitting Assessment Scale score in Level 4. There was no difference in adjustable seating system and custom-made orthosis in Sitting Assessment Scale in this group of children ( p < 0.017). Although custom-made orthosis fabrication is time consuming, it is still recommended since it is custom made, easy to use, and low-cost. On the other hand, the adjustable seating system can be modified according to a patient's height and weight. Clinical relevance It was found that Gross Motor Function Classification System Level 4 children benefitted most from the seating support systems. It was presented that standard chair is sufficient in providing postural alignment. Both custom-made orthosis and adjustable seating system have pros and cons and the best solution for each will be dependent on a number of factors.

Robust Adaptive Modified Newton Algorithm for Generalized Eigendecomposition and Its Application

NASA Astrophysics Data System (ADS)

Yang, Jian; Yang, Feng; Xi, Hong-Sheng; Guo, Wei; Sheng, Yanmin

2007-12-01

We propose a robust adaptive algorithm for generalized eigendecomposition problems that arise in modern signal processing applications. To that extent, the generalized eigendecomposition problem is reinterpreted as an unconstrained nonlinear optimization problem. Starting from the proposed cost function and making use of an approximation of the Hessian matrix, a robust modified Newton algorithm is derived. A rigorous analysis of its convergence properties is presented by using stochastic approximation theory. We also apply this theory to solve the signal reception problem of multicarrier DS-CDMA to illustrate its practical application. The simulation results show that the proposed algorithm has fast convergence and excellent tracking capability, which are important in a practical time-varying communication environment.

A modified JPEG-LS lossless compression method for remote sensing images

NASA Astrophysics Data System (ADS)

Deng, Lihua; Huang, Zhenghua

2015-12-01

As many variable length source coders, JPEG-LS is highly vulnerable to channel errors which occur in the transmission of remote sensing images. The error diffusion is one of the important factors which infect its robustness. The common method of improving the error resilience of JPEG-LS is dividing the image into many strips or blocks, and then coding each of them independently, but this method reduces the coding efficiency. In this paper, a block based JPEP-LS lossless compression method with an adaptive parameter is proposed. In the modified scheme, the threshold parameter RESET is adapted to an image and the compression efficiency is close to that of the conventional JPEG-LS.

A robust adaptive load frequency control for micro-grids.

PubMed

Khooban, Mohammad-Hassan; Niknam, Taher; Blaabjerg, Frede; Davari, Pooya; Dragicevic, Tomislav

2016-11-01

The goal of this study is to introduce a novel robust load frequency control (LFC) strategy for micro-grid(s) (MG(s)) in islanded mode operation. Admittedly, power generators in MG(s) cannot supply steady electric power output and sometimes cause unbalance between supply and demand. Battery energy storage system (BESS) is one of the effective solutions to these problems. Due to the high cost of the BESS, a new idea of Vehicle-to-Grid (V2G) is that a battery of Electric-Vehicle (EV) can be applied as a tantamount large-scale BESS in MG(s). As a result, a new robust control strategy for an islanded micro-grid (MG) is introduced that can consider electric vehicles׳ (EV(s)) effect. Moreover, in this paper, a new combination of the General Type II Fuzzy Logic Sets (GT2FLS) and the Modified Harmony Search Algorithm (MHSA) technique is applied for adaptive tuning of proportional-integral (PI) controller. Implementing General Type II Fuzzy Systems is computationally expensive. However, using a recently introduced α-plane representation, GT2FLS can be seen as a composition of several Interval Type II Fuzzy Logic Systems (IT2FLS) with a corresponding level of α for each. Real-data from an offshore wind farm in Sweden and solar radiation data in Aberdeen (United Kingdom) was used in order to examine the performance of the proposed novel controller. A comparison is made between the achieved results of Optimal Fuzzy-PI (OFPI) controller and those of Optimal Interval Type II Fuzzy-PI (IT2FPI) controller, which are of most recent advances in the area at hand. The Simulation results prove the successfulness and effectiveness of the proposed controller. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Adaptable Hydrogel Networks with Reversible Linkages for Tissue Engineering

PubMed Central

Wang, Huiyuan

2015-01-01

Adaptable hydrogels have recently emerged as a promising platform for three-dimensional (3D) cell encapsulation and culture. In conventional, covalently crosslinked hydrogels, degradation is typically required to allow complex cellular functions to occur, leading to bulk material degradation. In contrast, adaptable hydrogels are formed by reversible crosslinks. Through breaking and re-forming of the reversible linkages, adaptable hydrogels can be locally modified to permit complex cellular functions while maintaining their long-term integrity. In addition, these adaptable materials can have biomimetic viscoelastic properties that make them well suited for several biotechnology and medical applications. In this review, adaptable hydrogel design considerations and linkage selections are overviewed, with a focus on various cell compatible crosslinking mechanisms that can be exploited to form adaptable hydrogels for tissue engineering. PMID:25989348

Learning Effects of a Science Textbook Designed with Adapted Cognitive Process Principles on Grade 5 Students

ERIC Educational Resources Information Center

Cheng, Ming-Chang; Chou, Pei-I; Wang, Ya-Ting; Lin, Chih-Ho

2015-01-01

This study investigates how the illustrations in a science textbook, with their design modified according to cognitive process principles, affected students' learning performance. The quasi-experimental design recruited two Grade 5 groups (N?=?58) as the research participants. The treatment group (n?=?30) used the modified version of the textbook,…

Geobacteraceae strains and methods

DOEpatents

Lovley, Derek R.; Nevin, Kelly P.; Yi, Hana

2015-07-07

Embodiments of the present invention provide a method of producing genetically modified strains of electricigenic microbes that are specifically adapted for the production of electrical current in microbial fuel cells, as well as strains produced by such methods and fuel cells using such strains. In preferred embodiments, the present invention provides genetically modified strains of Geobacter sulfurreducens and methods of using such strains.

Teacher Efficacy and Preservice Teachers: A Construct Validation.

ERIC Educational Resources Information Center

Kushner, Susan N.

A construct validation of a modified version of a teacher efficiency scale was conducted to establish its use with preservice teachers. The scale adapted by A. E. Woolfolk and W. K. Hoy from one constructed by S. Gibson and M. H. Dembo, which contained 12 personal efficacy (PE) and 6 general teaching efficacy (TE) items, was further modified for…

The use of life-cycle assessment to evaluate the environmental impacts of growing genetically modified, nitrogen use-efficient canola.

PubMed

Strange, Alison; Park, Julian; Bennett, Richard; Phipps, Richard

2008-05-01

Agriculture, particularly intensive crop production, makes a significant contribution to environmental pollution. A variety of canola (Brassica napus) has been genetically modified to enhance nitrogen use efficiency, effectively reducing the amount of fertilizer required for crop production. A partial life-cycle assessment adapted to crop production was used to assess the potential environmental impacts of growing genetically modified, nitrogen use-efficient (GMNUE) canola in North Dakota and Minnesota compared with a conventionally bred control variety. The analysis took into account the entire production system used to produce 1 tonne of canola. This comprised raw material extraction, processing and transportation, as well as all agricultural field operations. All emissions associated with the production of 1 tonne of canola were listed, aggregated and weighted in order to calculate the level of environmental impact. The findings show that there are a range of potential environmental benefits associated with growing GMNUE canola. These include reduced impacts on global warming, freshwater ecotoxicity, eutrophication and acidification. Given the large areas of canola grown in North America and, in particular, Canada, as well as the wide acceptance of genetically modified varieties in this area, there is the potential for GMNUE canola to reduce pollution from agriculture, with the largest reductions predicted to be in greenhouse gases and diffuse water pollution.

A modified NARMAX model-based self-tuner with fault tolerance for unknown nonlinear stochastic hybrid systems with an input-output direct feed-through term.

PubMed

Tsai, Jason S-H; Hsu, Wen-Teng; Lin, Long-Guei; Guo, Shu-Mei; Tann, Joseph W

2014-01-01

A modified nonlinear autoregressive moving average with exogenous inputs (NARMAX) model-based state-space self-tuner with fault tolerance is proposed in this paper for the unknown nonlinear stochastic hybrid system with a direct transmission matrix from input to output. Through the off-line observer/Kalman filter identification method, one has a good initial guess of modified NARMAX model to reduce the on-line system identification process time. Then, based on the modified NARMAX-based system identification, a corresponding adaptive digital control scheme is presented for the unknown continuous-time nonlinear system, with an input-output direct transmission term, which also has measurement and system noises and inaccessible system states. Besides, an effective state space self-turner with fault tolerance scheme is presented for the unknown multivariable stochastic system. A quantitative criterion is suggested by comparing the innovation process error estimated by the Kalman filter estimation algorithm, so that a weighting matrix resetting technique by adjusting and resetting the covariance matrices of parameter estimate obtained by the Kalman filter estimation algorithm is utilized to achieve the parameter estimation for faulty system recovery. Consequently, the proposed method can effectively cope with partially abrupt and/or gradual system faults and input failures by the fault detection. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

Cultural adaptations to augment health and mental health services: a systematic review.

PubMed

Healey, Priscilla; Stager, Megan L; Woodmass, Kyler; Dettlaff, Alan J; Vergara, Andrew; Janke, Robert; Wells, Susan J

2017-01-05

Membership in diverse racial, ethnic, and cultural groups is often associated with inequitable health and mental health outcomes for diverse populations. Yet, little is known about how cultural adaptations of standard services affect health and mental health outcomes for service recipients. This systematic review identified extant themes in the research regarding cultural adaptations across a broad range of health and mental health services and synthesized the most rigorous experimental research available to isolate and evaluate potential efficacy gains of cultural adaptations to service delivery. MEDLINE, PsycINFO, CINAHL, EMBASE, and grey literature sources were searched for English-language studies published between January 1955 and January 2015. Cultural adaptations to any aspect of a service delivery were considered. Outcomes of interest included changes in service provider behavior or changes in the behavioral, medical, or self-reported experience of recipients. Thirty-one studies met the inclusion criteria. The most frequently tested adaptation occurred in preventive services and consisted of modifying the content of materials or services delivered. None of the included studies focused on making changes in the provider's behavior. Many different populations were studied but most research was concerned with the experiences and outcomes of African Americans. Seventeen of the 31 retained studies observed at least one significant effect in favor of a culturally adapted service. However there were also findings that favored the control group or showed no difference. Researchers did not find consistent evidence supporting implementation of any specific type of adaptation nor increased efficacy with any particular cultural group. Conceptual frameworks to classify cultural adaptations and their resultant health/mental health outcomes were developed and applied in a variety of ways. This review synthesizes the most rigorous research in the field and identifies implications for policy, practice, and research, including individualization, cost considerations, and patient or client satisfaction, among others.

Adaptive control applied to Space Station attitude control system

NASA Technical Reports Server (NTRS)

Lam, Quang M.; Chipman, Richard; Hu, Tsay-Hsin G.; Holmes, Eric B.; Sunkel, John

1992-01-01

This paper presents an adaptive control approach to enhance the performance of current attitude control system used by the Space Station Freedom. The proposed control law was developed based on the direct adaptive control or model reference adaptive control scheme. Performance comparisons, subject to inertia variation, of the adaptive controller and the fixed-gain linear quadratic regulator currently implemented for the Space Station are conducted. Both the fixed-gain and the adaptive gain controllers are able to maintain the Station stability for inertia variations of up to 35 percent. However, when a 50 percent inertia variation is applied to the Station, only the adaptive controller is able to maintain the Station attitude.

Bounded Linear Stability Margin Analysis of Nonlinear Hybrid Adaptive Control

NASA Technical Reports Server (NTRS)

Nguyen, Nhan T.; Boskovic, Jovan D.

2008-01-01

This paper presents a bounded linear stability analysis for a hybrid adaptive control that blends both direct and indirect adaptive control. Stability and convergence of nonlinear adaptive control are analyzed using an approximate linear equivalent system. A stability margin analysis shows that a large adaptive gain can lead to a reduced phase margin. This method can enable metrics-driven adaptive control whereby the adaptive gain is adjusted to meet stability margin requirements.

Biochemical upgrading of oils

DOEpatents

Premuzic, Eugene T.; Lin, Mow S.

1999-01-12

A process for biochemical conversion of heavy crude oils is provided. The process includes contacting heavy crude oils with adapted biocatalysts. The resulting upgraded oil shows, a relative increase in saturated hydrocarbons, emulsions and oxygenates and a decrease in compounds containing in organic sulfur, organic nitrogen and trace metals. Adapted microorganisms which have been modified under challenged growth processes are also disclosed.

System and method for cognitive processing for data fusion

NASA Technical Reports Server (NTRS)

Duong, Tuan A. (Inventor); Duong, Vu A. (Inventor)

2012-01-01

A system and method for cognitive processing of sensor data. A processor array receiving analog sensor data and having programmable interconnects, multiplication weights, and filters provides for adaptive learning in real-time. A static random access memory contains the programmable data for the processor array and the stored data is modified to provide for adaptive learning.

Biochemical upgrading of oils

DOEpatents

Premuzic, E.T.; Lin, M.S.

1999-01-12

A process for biochemical conversion of heavy crude oils is provided. The process includes contacting heavy crude oils with adapted biocatalysts. The resulting upgraded oil shows, a relative increase in saturated hydrocarbons, emulsions and oxygenates and a decrease in compounds containing organic sulfur, organic nitrogen and trace metals. Adapted microorganisms which have been modified under challenged growth processes are also disclosed. 121 figs.

The Application of the Monte Carlo Approach to Cognitive Diagnostic Computerized Adaptive Testing With Content Constraints

ERIC Educational Resources Information Center

Mao, Xiuzhen; Xin, Tao

2013-01-01

The Monte Carlo approach which has previously been implemented in traditional computerized adaptive testing (CAT) is applied here to cognitive diagnostic CAT to test the ability of this approach to address multiple content constraints. The performance of the Monte Carlo approach is compared with the performance of the modified maximum global…

Play Therapy for Bereaved Children: Adapting Strategies to Community, School, and Home Settings

ERIC Educational Resources Information Center

Webb, Nancy Boyd

2011-01-01

Play therapy is a highly adaptable treatment method that can be modified according to children's ages, circumstances, and settings in which counseling occurs. Play therapy may be used in schools, community settings, and homes to help children following the death of a significant other. After reviewing basic developmental factors that affect…

Effectiveness of Adaptive Pretend Play on Affective Expression and Imagination of Children with Cerebral Palsy

ERIC Educational Resources Information Center

Hsieh, Hsieh-Chun

2012-01-01

Purpose: Children with cerebral palsy (CP) have difficulty participating in role-pretending activities. The concept of adaptive play makes play accessible by modifying play materials for different needs or treatment goals for children with CP. This study examines the affective expressions and imagination in children with CP as a function of…

Can More Become Less? Effects of an Intensive Assessment Environment on Students' Learning Performance

ERIC Educational Resources Information Center

Khawaja, M. Asif; Prusty, Gangadhara B.; Ford, Robin A. J.; Marcus, Nadine; Russell, Carol

2013-01-01

Online interactive systems offer the beguiling prospect of an improved environment for learning at minimum extra cost. We have developed online interactive tutorials that adapt the learning environment to the current learning status of each individual student. These Adaptive Tutorials (ATs) modify the tasks given to each student according to their…

Conceptual design study of a Harrier V/STOL research aircraft

NASA Technical Reports Server (NTRS)

Bode, W. E.; Berger, R. L.; Elmore, G. A.; Lacey, T. R.

1978-01-01

MCAIR recently completed a conceptual design study to define modification approaches to, and derive planning prices for the conversion of a two place Harrier to a V/STOL control, display and guidance research aircraft. Control concepts such as rate damping, attitude stabilization, velocity command, and cockpit controllers are to be demonstrated. Display formats will also be investigated, and landing, navigation and guidance systems flight tested. The rear cockpit is modified such that it can be quickly adapted to faithfully simulate the controls, displays and handling qualities of a Type A or Type B V/STOL. The safety pilot always has take command capability. The modifications studied fall into two categories: basic modifications and optional modifications. Technical descriptions of the basic modifications and of the optional modifications are presented. The modification plan and schedule as well as the test plan and schedule are presented. The failure mode and effects analysis, aircraft performance, aircraft weight, and aircraft support are discussed.

Review of control strategies for robotic movement training after neurologic injury.

PubMed

Marchal-Crespo, Laura; Reinkensmeyer, David J

2009-06-16

There is increasing interest in using robotic devices to assist in movement training following neurologic injuries such as stroke and spinal cord injury. This paper reviews control strategies for robotic therapy devices. Several categories of strategies have been proposed, including, assistive, challenge-based, haptic simulation, and coaching. The greatest amount of work has been done on developing assistive strategies, and thus the majority of this review summarizes techniques for implementing assistive strategies, including impedance-, counterbalance-, and EMG- based controllers, as well as adaptive controllers that modify control parameters based on ongoing participant performance. Clinical evidence regarding the relative effectiveness of different types of robotic therapy controllers is limited, but there is initial evidence that some control strategies are more effective than others. It is also now apparent there may be mechanisms by which some robotic control approaches might actually decrease the recovery possible with comparable, non-robotic forms of training. In future research, there is a need for head-to-head comparison of control algorithms in randomized, controlled clinical trials, and for improved models of human motor recovery to provide a more rational framework for designing robotic therapy control strategies.

Review of control strategies for robotic movement training after neurologic injury

PubMed Central

Marchal-Crespo, Laura; Reinkensmeyer, David J

2009-01-01

There is increasing interest in using robotic devices to assist in movement training following neurologic injuries such as stroke and spinal cord injury. This paper reviews control strategies for robotic therapy devices. Several categories of strategies have been proposed, including, assistive, challenge-based, haptic simulation, and coaching. The greatest amount of work has been done on developing assistive strategies, and thus the majority of this review summarizes techniques for implementing assistive strategies, including impedance-, counterbalance-, and EMG- based controllers, as well as adaptive controllers that modify control parameters based on ongoing participant performance. Clinical evidence regarding the relative effectiveness of different types of robotic therapy controllers is limited, but there is initial evidence that some control strategies are more effective than others. It is also now apparent there may be mechanisms by which some robotic control approaches might actually decrease the recovery possible with comparable, non-robotic forms of training. In future research, there is a need for head-to-head comparison of control algorithms in randomized, controlled clinical trials, and for improved models of human motor recovery to provide a more rational framework for designing robotic therapy control strategies. PMID:19531254

Interspecific correlates of plasticity in relative growth rate following a decrease in nitrogen availability.

PubMed

Useche, Antonio; Shipley, Bill

2010-02-01

Nitrogen availability varies greatly over short time scales. This requires that a well-adapted plant modify its phenotype by an appropriate amount and at a certain speed in order to maximize growth and fitness. To determine how plastic ontogenetic changes in each trait interact and whether or not these changes are likely to maximize growth, ontogenetic changes in relative growth rate (RGR), net assimilation rate (NAR), specific leaf area (SLA) and root weight ratio (RWR), before and after a decrease in nitrogen supply, were studied in 14 herbaceous species. Forty-four plants of each species were grown in hydroponic culture under controlled conditions in a control treatment where the supply of nitrogen remained constant at 1 mm, and in a stress treatment where the nitrogen supply was abruptly decreased from 1 to 0.01 mm during the growth period. In the treatment series, and in comparison with the control, NAR and RGR decreased, RWR increased, and SLA did not change except for the timing of ontogenetic change. Species having greater increases in the maximum rate of change in RWR also had smaller reductions in RGR; plasticity in RWR is therefore adaptive. In contrast, species which showed a greater decrease in NAR showed stronger reductions in RGR; plasticity in NAR is therefore not adaptive. Plasticity in RGR was not related to plasticity in SLA. There were no significant relationships among the plasticities in NAR, RWR or SLA. Potentially fast-growing species experienced larger reductions in RGR following the nitrogen reduction. These results suggest that competitive responses to interspecific competition for nitrogen might be positively correlated with the plasticity in the maximum rate of change in RWR in response to a reduction in nitrogen supply.

Advances in Adaptive Control Methods

NASA Technical Reports Server (NTRS)

Nguyen, Nhan

2009-01-01

This poster presentation describes recent advances in adaptive control technology developed by NASA. Optimal Control Modification is a novel adaptive law that can improve performance and robustness of adaptive control systems. A new technique has been developed to provide an analytical method for computing time delay stability margin for adaptive control systems.

Pilot Evaluation of Adaptive Control in Motion-Based Flight Simulator

NASA Technical Reports Server (NTRS)

Kaneshige, John T.; Campbell, Stefan Forrest

2009-01-01

The objective of this work is to assess the strengths, weaknesses, and robustness characteristics of several MRAC (Model-Reference Adaptive Control) based adaptive control technologies garnering interest from the community as a whole. To facilitate this, a control study using piloted and unpiloted simulations to evaluate sensitivities and handling qualities was conducted. The adaptive control technologies under consideration were ALR (Adaptive Loop Recovery), BLS (Bounded Linear Stability), Hybrid Adaptive Control, L1, OCM (Optimal Control Modification), PMRAC (Predictor-based MRAC), and traditional MRAC

m-BIRCH: an online clustering approach for computer vision applications

NASA Astrophysics Data System (ADS)

Madan, Siddharth K.; Dana, Kristin J.

2015-03-01

We adapt a classic online clustering algorithm called Balanced Iterative Reducing and Clustering using Hierarchies (BIRCH), to incrementally cluster large datasets of features commonly used in multimedia and computer vision. We call the adapted version modified-BIRCH (m-BIRCH). The algorithm uses only a fraction of the dataset memory to perform clustering, and updates the clustering decisions when new data comes in. Modifications made in m-BIRCH enable data driven parameter selection and effectively handle varying density regions in the feature space. Data driven parameter selection automatically controls the level of coarseness of the data summarization. Effective handling of varying density regions is necessary to well represent the different density regions in data summarization. We use m-BIRCH to cluster 840K color SIFT descriptors, and 60K outlier corrupted grayscale patches. We use the algorithm to cluster datasets consisting of challenging non-convex clustering patterns. Our implementation of the algorithm provides an useful clustering tool and is made publicly available.

Adaptive cockroach swarm algorithm

NASA Astrophysics Data System (ADS)

Obagbuwa, Ibidun C.; Abidoye, Ademola P.

2017-07-01

An adaptive cockroach swarm optimization (ACSO) algorithm is proposed in this paper to strengthen the existing cockroach swarm optimization (CSO) algorithm. The ruthless component of CSO algorithm is modified by the employment of blend crossover predator-prey evolution method which helps algorithm prevent any possible population collapse, maintain population diversity and create adaptive search in each iteration. The performance of the proposed algorithm on 16 global optimization benchmark function problems was evaluated and compared with the existing CSO, cuckoo search, differential evolution, particle swarm optimization and artificial bee colony algorithms.

Adaptive control of a Stewart platform-based manipulator

NASA Technical Reports Server (NTRS)

Nguyen, Charles C.; Antrazi, Sami S.; Zhou, Zhen-Lei; Campbell, Charles E., Jr.

1993-01-01

A joint-space adaptive control scheme for controlling noncompliant motion of a Stewart platform-based manipulator (SPBM) was implemented in the Hardware Real-Time Emulator at Goddard Space Flight Center. The six-degrees of freedom SPBM uses two platforms and six linear actuators driven by dc motors. The adaptive control scheme is based on proportional-derivative controllers whose gains are adjusted by an adaptation law based on model reference adaptive control and Liapunov direct method. It is concluded that the adaptive control scheme provides superior tracking capability as compared to fixed-gain controllers.

Exposure to a Rotating Virtual Environment During Treadmill Locomotion Causes Adaptation in Heading Direction

NASA Technical Reports Server (NTRS)

Ruttley, T; Marshburn, A.; Bloomberg, J. J.; Mulavara, A. P.; Richards, J. T.; Nomura, Y.

2005-01-01

The goal of the present study was to investigate the adaptive effects of variation in the direction of optic flow, experienced during linear treadmill walking, on modifying locomotor trajectory. Subjects (n = 30) walked on a motorized linear treadmill at 4.0 kilometers per hour for 24 minutes while viewing the interior of a 3D virtual scene projected onto a screen 1.5 in in front of them. The virtual scene depicted constant self-motion equivalent to either 1) walking around the perimeter of a room to one s left (Rotating Room group) 2) walking down the center of a hallway (Infinite Hallway group). The scene was static for the first 4 minutes, and then constant rate self-motion was simulated for the remaining 20 minutes. Before and after the treadmill locomotion adaptation period, subjects performed five stepping trials where in each trial they marched in place to the beat of a metronome at 90 steps/min while blindfolded in a quiet room. The subject's final heading direction (deg), final X (for-aft, cm) and final Y (medio-lateral, cm) positions were measured for each trial. During the treadmill locomotion adaptation period subject's 3D torso position was measured. We found that subjects in the Rotating Room group as compared to the Infinite Hallway group: 1) showed significantly greater deviation during post exposure testing in the heading direction and Y position opposite to the direction of optic flow experienced during treadmill walking 2) showed a significant monotonically increasing torso yaw angular rotation bias in the direction of optic flow during the treadmill adaptation exposure period. Subjects in both groups showed greater forward translation (in the +X direction) during the post treadmill stepping task that differed significantly from their pre exposure performance. Subjects in both groups reported no perceptual deviation in position during the stepping tasks. We infer that viewing simulated rotary self-motion during treadmill locomotion causes adaptive modification of sensory-motor integration in the control of position and trajectory during locomotion which functionally reflects adaptive changes in the integration of visual, vestibular, and proprioceptive cues. Such an adaptation in the control of position and heading direction during locomotion due to the congruence of sensory information demonstrates the potential for adaptive transfer between sensorimotor systems and suggests a common neural site for the processing and self-motion perception and concurrent adaptation in motor output. This will result in lack of subjects perception of deviation of position and trajectory during the post treadmill step test while blind folded.

Exposure to a Rotating Virtual Environment During Treadmill Locomotion Causes Adaptation in Heading Direction

NASA Technical Reports Server (NTRS)

Mulavara, A. P.; Richards, J. T.; Marshburn, A.; Nomura, Y.; Bloomberg, J. J.

2005-01-01

The goal of the present study was to investigate the adaptive effects of variation in the direction of optic flow, experienced during linear treadmill walking, on modifying locomotor trajectory. Subjects (n = 30) walked on a motorized linear treadmill at 4.0 km/h for 24 minutes while viewing the interior of a 3D virtual scene projected onto a screen 1.5 m in front of them. The virtual scene depicted constant self-motion equivalent to either 1) walking around the perimeter of a room to one s left (Rotating Room group) 2) walking down the center of a hallway (Infinite Hallway group). The scene was static for the first 4 minutes, and then constant rate self-motion was simulated for the remaining 20 minutes. Before and after the treadmill locomotion adaptation period, subjects performed five stepping trials where in each trial they marched in place to the beat of a metronome at 90 steps/min while blindfolded in a quiet room. The subject s final heading direction (deg), final X (for-aft, cm) and final Y (medio-lateral, cm) positions were measured for each trial. During the treadmill locomotion adaptation period subject s 3D torso position was measured. We found that subjects in the Rotating Room group as compared to the Infinite Hallway group: 1) showed significantly greater deviation during post exposure testing in the heading direction and Y position opposite to the direction of optic flow experienced during treadmill walking 2) showed a significant monotonically increasing torso yaw angular rotation bias in the direction of optic flow during the treadmill adaptation exposure period. Subjects in both groups showed greater forward translation (in the +X direction) during the post treadmill stepping task that differed significantly from their pre exposure performance. Subjects in both groups reported no perceptual deviation in position during the stepping tasks. We infer that 3 viewing simulated rotary self-motion during treadmill locomotion causes adaptive modification of sensory-motor integration in the control of position and trajectory during locomotion which functionally reflects adaptive changes in the integration of visual, vestibular, and proprioceptive cues. Such an adaptation in the control of position and heading direction during locomotion due to the congruence of sensory information demonstrates the potential for adaptive transfer between sensorimotor systems and suggests a common neural site for the processing and self-motion perception and concurrent adaptation in motor output. This will result in lack of subjects perception of deviation of position and trajectory during the post treadmill step test while blind folded.

Changes in the lipid composition of Bradyrhizobium cell envelope reveal a rapid response to water deficit involving lysophosphatidylethanolamine synthesis from phosphatidylethanolamine in outer membrane.

PubMed

Cesari, Adriana B; Paulucci, Natalia S; Biasutti, María A; Morales, Gustavo M; Dardanelli, Marta S

2018-06-02

We evaluate the behavior of the membrane of Bradyrhizobium sp. SEMIA6144 during adaptation to polyethylene glycol (PEG). A dehydrating effect on the morphology of the cell surface, as well as a fluidizing effect on the membrane was observed 10 min after PEG shock; however, the bacteria were able to restore optimal membrane fluidity. Shock for 1 h caused an increase of lysophosphatidylethanolamine in the outer membrane at the expense of phosphatidylcholine and phosphatidylethanolamine (PE), through an increase in phospholipase activity. The amount of lysophosphatidylethanolamine did not remain constant during PEG shock, but after 24 h the outer membrane was composed of large amounts of phosphatidylcholine and less amount of lysophosphatidylethanolamine similar to the control. The inner membrane composition was also modified after 1 h of shock, observing an increase of phosphatidylcholine at the expense of PE, the proportions of these phospholipids were then modified to reach 24 h of shock values similar to the control. Vesicles prepared with the lipids of cells exposed to 1 h shock presented higher rigidity compared to the control, indicating that changes in the composition of phospholipids after 1 h of shock restoring fluidity after the PEG effect and would allow cells to maintain surface morphology. Copyright © 2018 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Compensation for loads during arm movements using equilibrium-point control.

PubMed

Gribble, P L; Ostry, D J

2000-12-01

A significant problem in motor control is how information about movement error is used to modify control signals to achieve desired performance. A potential source of movement error and one that is readily controllable experimentally relates to limb dynamics and associated movement-dependent loads. In this paper, we have used a position control model to examine changes to control signals for arm movements in the context of movement-dependent loads. In the model, based on the equilibrium-point hypothesis, equilibrium shifts are adjusted directly in proportion to the positional error between desired and actual movements. The model is used to simulate multi-joint movements in the presence of both "internal" loads due to joint interaction torques, and externally applied loads resulting from velocity-dependent force fields. In both cases it is shown that the model can achieve close correspondence to empirical data using a simple linear adaptation procedure. An important feature of the model is that it achieves compensation for loads during movement without the need for either coordinate transformations between positional error and associated corrective forces, or inverse dynamics calculations.

Predictors of the Aspiration Component Success of a Direct Aspiration First Pass Technique (ADAPT) for the Endovascular Treatment of Stroke Reperfusion Strategy in Anterior Circulation Acute Stroke.

PubMed

Blanc, Raphaël; Redjem, Hocine; Ciccio, Gabriele; Smajda, Stanislas; Desilles, Jean-Philippe; Orng, Eliane; Taylor, Guillaume; Drumez, Elodie; Fahed, Robert; Labreuche, Julien; Mazighi, Mikael; Lapergue, Bertrand; Piotin, Michel

2017-06-01

A direct aspiration first pass technique (ADAPT) has been reported to be fast, safe, and effective for the treatment of acute ischemic stroke. The aim of this study is to determine the preoperative factors that affect success of the aspiration component of the technique in ischemic stroke patients with large vessel occlusion in the anterior circulation. We enrolled all 347 consecutive patients with anterior circulation acute ischemic stroke admitted for mechanical thrombectomy at our institution from August 2013 to October 2015 and treated by ADAPT for the endovascular treatment of stroke. Baseline and procedural characteristics, modified thrombolysis in cerebral infarction scores, and 3-month modified Rankin Scale were captured and analyzed. Among the 347 patients (occlusion sites: middle cerebral artery=200, 58%; internal carotid artery Siphon=89, 25%; Tandem=58, 17%), aspiration component led to successful reperfusion (modified thrombolysis in cerebral infarction 2b/3 scores) in 55.6% (193/347 patients), stent retrievers were required in 40%, and a total successful final reperfusion rate of 83% (288/347) was achieved. Overall, procedural complications occurred in 13.3% of patients (48/347). Modified Rankin Scale score of 0 to 2 at 90 days was reported in 45% (144/323). Only 2 factors positively influenced the success of the aspiration component: an isolated middle cerebral artery occlusion ( P <0.001) and a shorter time from stroke onset to clot contact ( P =0.018). In this large retrospective study, ADAPT was shown to be safe and effective for anterior circulation acute ischemic stroke with a final successful reperfusion achieved in 83%. The site of arterial occlusion and delay of the procedure were predictors for reperfusion. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02523261, NCT02678169, and NCT02466893. © 2017 American Heart Association, Inc.

Ecology of Anopheles darlingi Root with respect to vector importance: a review

PubMed Central

2011-01-01

Anopheles darlingi is one of the most important malaria vectors in the Americas. In this era of new tools and strategies for malaria and vector control it is essential to have knowledge on the ecology and behavior of vectors in order to evaluate appropriateness and impact of control measures. This paper aims to provide information on the importance, ecology and behavior of An. darlingi. It reviews publications that addressed ecological and behavioral aspects that are important to understand the role and importance of An. darlingi in the transmission of malaria throughout its area of distribution. The results show that Anopheles darlingi is especially important for malaria transmission in the Amazon region. Although numerous studies exist, many aspects determining the vectorial capacity of An. darlingi, i.e. its relation to seasons and environmental conditions, its gonotrophic cycle and longevity, and its feeding behavior and biting preferences, are still unknown. The vector shows a high degree of variability in behavioral traits. This makes it difficult to predict the impact of ongoing changes in the environment on the mosquito populations. Recent studies indicate a good ability of An. darlingi to adapt to environments modified by human development. This allows the vector to establish populations in areas where it previously did not exist or had been controlled to date. The behavioral variability of the vector, its adaptability, and our limited knowledge of these impede the establishment of effective control strategies. Increasing our knowledge of An. darlingi is necessary. PMID:21923902

Dual-arm manipulators with adaptive control

NASA Technical Reports Server (NTRS)

Seraji, Homayoun (Inventor)

1991-01-01

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

Method and apparatus for adaptive force and position control of manipulators

NASA Technical Reports Server (NTRS)

Seraji, Homayoun (Inventor)

1995-01-01

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

An Adaptive Supervisory Sliding Fuzzy Cerebellar Model Articulation Controller for Sensorless Vector-Controlled Induction Motor Drive Systems

PubMed Central

Wang, Shun-Yuan; Tseng, Chwan-Lu; Lin, Shou-Chuang; Chiu, Chun-Jung; Chou, Jen-Hsiang

2015-01-01

This paper presents the implementation of an adaptive supervisory sliding fuzzy cerebellar model articulation controller (FCMAC) in the speed sensorless vector control of an induction motor (IM) drive system. The proposed adaptive supervisory sliding FCMAC comprised a supervisory controller, integral sliding surface, and an adaptive FCMAC. The integral sliding surface was employed to eliminate steady-state errors and enhance the responsiveness of the system. The adaptive FCMAC incorporated an FCMAC with a compensating controller to perform a desired control action. The proposed controller was derived using the Lyapunov approach, which guarantees learning-error convergence. The implementation of three intelligent control schemes—the adaptive supervisory sliding FCMAC, adaptive sliding FCMAC, and adaptive sliding CMAC—were experimentally investigated under various conditions in a realistic sensorless vector-controlled IM drive system. The root mean square error (RMSE) was used as a performance index to evaluate the experimental results of each control scheme. The analysis results indicated that the proposed adaptive supervisory sliding FCMAC substantially improved the system performance compared with the other control schemes. PMID:25815450

An adaptive supervisory sliding fuzzy cerebellar model articulation controller for sensorless vector-controlled induction motor drive systems.

PubMed

Wang, Shun-Yuan; Tseng, Chwan-Lu; Lin, Shou-Chuang; Chiu, Chun-Jung; Chou, Jen-Hsiang

2015-03-25

This paper presents the implementation of an adaptive supervisory sliding fuzzy cerebellar model articulation controller (FCMAC) in the speed sensorless vector control of an induction motor (IM) drive system. The proposed adaptive supervisory sliding FCMAC comprised a supervisory controller, integral sliding surface, and an adaptive FCMAC. The integral sliding surface was employed to eliminate steady-state errors and enhance the responsiveness of the system. The adaptive FCMAC incorporated an FCMAC with a compensating controller to perform a desired control action. The proposed controller was derived using the Lyapunov approach, which guarantees learning-error convergence. The implementation of three intelligent control schemes--the adaptive supervisory sliding FCMAC, adaptive sliding FCMAC, and adaptive sliding CMAC--were experimentally investigated under various conditions in a realistic sensorless vector-controlled IM drive system. The root mean square error (RMSE) was used as a performance index to evaluate the experimental results of each control scheme. The analysis results indicated that the proposed adaptive supervisory sliding FCMAC substantially improved the system performance compared with the other control schemes.

Diversity and function of bacterial microbiota in the mosquito holobiont

PubMed Central

2013-01-01

Mosquitoes (Diptera: Culicidae) have been shown to host diverse bacterial communities that vary depending on the sex of the mosquito, the developmental stage, and ecological factors. Some studies have suggested a potential role of microbiota in the nutritional, developmental and reproductive biology of mosquitoes. Here, we present a review of the diversity and functions of mosquito-associated bacteria across multiple variation factors, emphasizing recent findings. Mosquito microbiota is considered in the context of possible extended phenotypes conferred on the insect hosts that allow niche diversification and rapid adaptive evolution in other insects. These kinds of observations have prompted the recent development of new mosquito control methods based on the use of symbiotically-modified mosquitoes to interfere with pathogen transmission or reduce the host life span and reproduction. New opportunities for exploiting bacterial function for vector control are highlighted. PMID:23688194

Diet and Blood Pressure Control in Chinese Canadians: Cultural Considerations.

PubMed

Zou, Ping

2017-04-01

Hypertension is highly prevalent in Chinese Canadians and diet has been identified as an important modifiable risk factor for hypertension. The current anti-hypertensive dietary recommendations in hypertension care guidelines lack examination of cultural factors, are not culturally sensitive to ethnic populations, and cannot be translated to Chinese Canadian populations without cultural considerations. Guided by Leininger's Sunrise Model of culture care theory, this paper investigates how cultural factors impact Chinese Canadians' dietary practice. It is proposed that English language proficiency, health literacy, traditional Chinese diet, migration and acculturation, and Traditional Chinese Medicine influence Chinese Canadians' dietary practices. A culturally congruent nursing intervention should be established and tailored according to related cultural factors to facilitate Chinese Canadians' blood pressure control. In addition, further study is needed to test the model adapted from Sunrise Model and understand its mechanism.

Study of tethered satellite active attitude control

NASA Technical Reports Server (NTRS)

Colombo, G.

1982-01-01

Existing software was adapted for the study of tethered subsatellite rotational dynamics, an analytic solution for a stable configuration of a tethered subsatellite was developed, the analytic and numerical integrator (computer) solutions for this "test case' was compared in a two mass tether model program (DUMBEL), the existing multiple mass tether model (SKYHOOK) was modified to include subsatellite rotational dynamics, the analytic "test case,' was verified, and the use of the SKYHOOK rotational dynamics capability with a computer run showing the effect of a single off axis thruster on the behavior of the subsatellite was demonstrated. Subroutines for specific attitude control systems are developed and applied to the study of the behavior of the tethered subsatellite under realistic on orbit conditions. The effect of all tether "inputs,' including pendular oscillations, air drag, and electrodynamic interactions, on the dynamic behavior of the tether are included.

Activation of caspase-1 by the NLRP3 inflammasome regulates the NADPH oxidase NOX2 to control phagosome function

PubMed Central

Sokolovska, Anna; Becker, Christine E.; Eddie Ip, WK; Rathinam, Vijay A.K.; Brudner, Matthew; Paquette, Nicholas; Tanne, Antoine; Vanaja, Sivapriya K.; Moore, Kathryn J.; Fitzgerald, Katherine A.; Lacy-Hulbert, Adam; Stuart, Lynda M.

2013-01-01

Phagocytosis is a fundamental cellular process that is pivotal for immunity as it coordinates microbial killing, innate immune activation and antigen presentation. An essential step in this process is phagosome acidification, which regulates a number of functions of these organelles that allow them to participate in processes essential to both innate and adaptive immunity. Here we report that acidification of phagosomes containing Gram-positive bacteria is regulated by the NLRP3-inflammasome and caspase-1. Active caspase-1 accumulates on phagosomes and acts locally to control the pH by modulating buffering by the NADPH oxidase NOX2. These data provide insight into a mechanism by which innate immune signals can modify cellular defenses and establish a new function for the NLRP3-inflammasome and caspase-1 in host defense. PMID:23644505

Adaptive Control Using Residual Mode Filters Applied to Wind Turbines

NASA Technical Reports Server (NTRS)

Frost, Susan A.; Balas, Mark J.

2011-01-01

Many dynamic systems containing a large number of modes can benefit from adaptive control techniques, which are well suited to applications that have unknown parameters and poorly known operating conditions. In this paper, we focus on a model reference direct adaptive control approach that has been extended to handle adaptive rejection of persistent disturbances. We extend this adaptive control theory to accommodate problematic modal subsystems of a plant that inhibit the adaptive controller by causing the open-loop plant to be non-minimum phase. We will augment the adaptive controller using a Residual Mode Filter (RMF) to compensate for problematic modal subsystems, thereby allowing the system to satisfy the requirements for the adaptive controller to have guaranteed convergence and bounded gains. We apply these theoretical results to design an adaptive collective pitch controller for a high-fidelity simulation of a utility-scale, variable-speed wind turbine that has minimum phase zeros.

Adaptive Control Allocation in the Presence of Actuator Failures

NASA Technical Reports Server (NTRS)

Liu, Yu; Crespo, Luis G.

2010-01-01

In this paper, a novel adaptive control allocation framework is proposed. In the adaptive control allocation structure, cooperative actuators are grouped and treated as an equivalent control effector. A state feedback adaptive control signal is designed for the equivalent effector and allocated to the member actuators adaptively. Two adaptive control allocation algorithms are proposed, which guarantee closed-loop stability and asymptotic state tracking in the presence of uncertain loss of effectiveness and constant-magnitude actuator failures. The proposed algorithms can be shown to reduce the controller complexity with proper grouping of the actuators. The proposed adaptive control allocation schemes are applied to two linearized aircraft models, and the simulation results demonstrate the performance of the proposed algorithms.

Neural network based adaptive control for nonlinear dynamic regimes

NASA Astrophysics Data System (ADS)

Shin, Yoonghyun

Adaptive control designs using neural networks (NNs) based on dynamic inversion are investigated for aerospace vehicles which are operated at highly nonlinear dynamic regimes. NNs play a key role as the principal element of adaptation to approximately cancel the effect of inversion error, which subsequently improves robustness to parametric uncertainty and unmodeled dynamics in nonlinear regimes. An adaptive control scheme previously named 'composite model reference adaptive control' is further developed so that it can be applied to multi-input multi-output output feedback dynamic inversion. It can have adaptive elements in both the dynamic compensator (linear controller) part and/or in the conventional adaptive controller part, also utilizing state estimation information for NN adaptation. This methodology has more flexibility and thus hopefully greater potential than conventional adaptive designs for adaptive flight control in highly nonlinear flight regimes. The stability of the control system is proved through Lyapunov theorems, and validated with simulations. The control designs in this thesis also include the use of 'pseudo-control hedging' techniques which are introduced to prevent the NNs from attempting to adapt to various actuation nonlinearities such as actuator position and rate saturations. Control allocation is introduced for the case of redundant control effectors including thrust vectoring nozzles. A thorough comparison study of conventional and NN-based adaptive designs for a system under a limit cycle, wing-rock, is included in this research, and the NN-based adaptive control designs demonstrate their performances for two highly maneuverable aerial vehicles, NASA F-15 ACTIVE and FQM-117B unmanned aerial vehicle (UAV), operated under various nonlinearities and uncertainties.

Real-time performance assessment and adaptive control for a water chiller unit in an HVAC system

NASA Astrophysics Data System (ADS)

Bai, Jianbo; Li, Yang; Chen, Jianhao

2018-02-01

The paper proposes an adaptive control method for a water chiller unit in a HVAC system. Based on the minimum variance evaluation, the adaptive control method was used to realize better control of the water chiller unit. To verify the performance of the adaptive control method, the proposed method was compared with an a conventional PID controller, the simulation results showed that adaptive control method had superior control performance to that of the conventional PID controller.

The Use of Hybrid Terms and Expressions in Colloquial Arabic among Jordanian College Students: A Sociolinguistic Study

ERIC Educational Resources Information Center

Jaran, Samia A.; Al-Haq, Fawwaz Al-Abed

2015-01-01

Languages tend to be modified to accommodate for the speakers needs, such as, discussing or dealing with certain topics and domains. An example, university students, in Jordan, modify their own language, being colloquial Arabic, with terms and expressions from the English language in order to interact and adapt to everyday college life. Due to…

Adjustment of Adaptive Gain with Bounded Linear Stability Analysis to Improve Time-Delay Margin for Metrics-Driven Adaptive Control

NASA Technical Reports Server (NTRS)

Bakhtiari-Nejad, Maryam; Nguyen, Nhan T.; Krishnakumar, Kalmanje Srinvas

2009-01-01

This paper presents the application of Bounded Linear Stability Analysis (BLSA) method for metrics driven adaptive control. The bounded linear stability analysis method is used for analyzing stability of adaptive control models, without linearizing the adaptive laws. Metrics-driven adaptive control introduces a notion that adaptation should be driven by some stability metrics to achieve robustness. By the application of bounded linear stability analysis method the adaptive gain is adjusted during the adaptation in order to meet certain phase margin requirements. Analysis of metrics-driven adaptive control is evaluated for a linear damaged twin-engine generic transport model of aircraft. The analysis shows that the system with the adjusted adaptive gain becomes more robust to unmodeled dynamics or time delay.

Adoptive cellular therapy of cancer: exploring innate and adaptive cellular crosstalk to improve anti-tumor efficacy.

PubMed

Payne, Kyle K; Bear, Harry D; Manjili, Masoud H

2014-08-01

The mammalian immune system has evolved to produce multi-tiered responses consisting of both innate and adaptive immune cells collaborating to elicit a functional response to a pathogen or neoplasm. Immune cells possess a shared ancestry, suggestive of a degree of coevolution that has resulted in optimal functionality as an orchestrated and highly collaborative unit. Therefore, the development of therapeutic modalities that harness the immune system should consider the crosstalk between cells of the innate and adaptive immune systems in order to elicit the most effective response. In this review, the authors will discuss the success achieved using adoptive cellular therapy in the treatment of cancer, recent trends that focus on purified T cells, T cells with genetically modified T-cell receptors and T cells modified to express chimeric antigen receptors, as well as the use of unfractionated immune cell reprogramming to achieve optimal cellular crosstalk upon infusion for adoptive cellular therapy.

Resilience, Integrity and Ecosystem Dynamics: Bridging Ecosystem Theory and Management

NASA Astrophysics Data System (ADS)

Müller, Felix; Burkhard, Benjamin; Kroll, Franziska

In this paper different approaches to elucidate ecosystem dynamics are described, illustrated and interrelated. Ecosystem development is distinguished into two separate sequences, a complexifying phase which is characterized by orientor optimization and a destruction based phase which follows disturbances. The two developmental pathways are integrated in a modified illustration of the “adaptive cycle”. Based on these fundamentals, the recent definitions of resilience, adaptability and vulnerability are discussed and a modified comprehension is proposed. Thereafter, two case studies about wetland dynamics are presented to demonstrate both, the consequences of disturbance and the potential of ecosystem recovery. In both examples ecosystem integrity is used as a key indicator variable. Based on the presented results the relativity and the normative loading of resilience quantification is worked out. The paper ends with the suggestion that the features of adaptability could be used as an integrative guideline for the analysis of ecosystem dynamics and as a well-suited concept for ecosystem management.

Educational X-Ray Experiments and XRF Measurements with a Portable Setup Adapted for the Characterization of Cultural Heritage Objects

ERIC Educational Resources Information Center

Sianoudis, I.; Drakaki, E.; Hein, A.

2010-01-01

It is common to modify valuable, sophisticated equipment, originally acquired for other purposes, to adapt it for the needs of educational experiments, with great didactic effectiveness. The present project concerns a setup developed from components of a portable system for energy dispersive x-ray fluorescence spectroscopy (EDXRF). Two educational…

The American Association on Mental Deficiency-Adaptive Behavior Scale: Allowing Credit for Alternative Means of Communication.

ERIC Educational Resources Information Center

Suess, James F.; And Others

1983-01-01

Compared were the Adaptive Behavior Scale (ABS) and a modified version of the ABS (which allowed alternative methods of communication such as sign language) with 134 deaf-blind persons, three to 30 years old. Among results were that alternative communication methods had no effect on nine of 10 ABS domains. (Author/MC)

The design and implementation of radar clutter modelling and adaptive target detection techniques

NASA Astrophysics Data System (ADS)

Ali, Mohammed Hussain

The analysis and reduction of radar clutter is investigated. Clutter is the term applied to unwanted radar reflections from land, sea, precipitation, and/or man-made objects. A great deal of useful information regarding the characteristics of clutter can be obtained by the application of frequency domain analytical methods. Thus, some considerable time was spent assessing the various techniques available and their possible application to radar clutter. In order to better understand clutter, use of a clutter model was considered desirable. There are many techniques which will enable a target to be detected in the presence of clutter. One of the most flexible of these is that of adaptive filtering. This technique was thoroughly investigated and a method for improving its efficacy was devised. The modified adaptive filter employed differential adaption times to enhance detectability. Adaptation time as a factor relating to target detectability is a new concept and was investigated in some detail. It was considered desirable to implement the theoretical work in dedicated hardware to confirm that the modified clutter model and the adaptive filter technique actually performed as predicted. The equipment produced is capable of operation in real time and provides an insight into real time DSP applications. This equipment is sufficiently rapid to produce a real time display on the actual PPI system. Finally a software package was also produced which would simulate the operation of a PPI display and thus ease the interpretation of the filter outputs.

An Evidence-Based Public Health Approach to Climate Change Adaptation

PubMed Central

Eidson, Millicent; Tlumak, Jennifer E.; Raab, Kristin K.; Luber, George

2014-01-01

Background: Public health is committed to evidence-based practice, yet there has been minimal discussion of how to apply an evidence-based practice framework to climate change adaptation. Objectives: Our goal was to review the literature on evidence-based public health (EBPH), to determine whether it can be applied to climate change adaptation, and to consider how emphasizing evidence-based practice may influence research and practice decisions related to public health adaptation to climate change. Methods: We conducted a substantive review of EBPH, identified a consensus EBPH framework, and modified it to support an EBPH approach to climate change adaptation. We applied the framework to an example and considered implications for stakeholders. Discussion: A modified EBPH framework can accommodate the wide range of exposures, outcomes, and modes of inquiry associated with climate change adaptation and the variety of settings in which adaptation activities will be pursued. Several factors currently limit application of the framework, including a lack of higher-level evidence of intervention efficacy and a lack of guidelines for reporting climate change health impact projections. To enhance the evidence base, there must be increased attention to designing, evaluating, and reporting adaptation interventions; standardized health impact projection reporting; and increased attention to knowledge translation. This approach has implications for funders, researchers, journal editors, practitioners, and policy makers. Conclusions: The current approach to EBPH can, with modifications, support climate change adaptation activities, but there is little evidence regarding interventions and knowledge translation, and guidelines for projecting health impacts are lacking. Realizing the goal of an evidence-based approach will require systematic, coordinated efforts among various stakeholders. Citation: Hess JJ, Eidson M, Tlumak JE, Raab KK, Luber G. 2014. An evidence-based public health approach to climate change adaptation. Environ Health Perspect 122:1177–1186; http://dx.doi.org/10.1289/ehp.1307396 PMID:25003495

Enzymatically Modified Starch Ameliorates Postprandial Serum Triglycerides and Lipid Metabolome in Growing Pigs.

PubMed

Metzler-Zebeli, Barbara U; Eberspächer, Eva; Grüll, Dietmar; Kowalczyk, Lidia; Molnar, Timea; Zebeli, Qendrim

2015-01-01

Developing host digestion-resistant starches to promote human health is of great research interest. Chemically modified starches (CMS) are widely used in processed foods and although the modification of the starch molecule allows specific reduction in digestibility, the metabolic effects of CMS have been less well described. This short-term study evaluated the impact of enzymatically modified starch (EMS) on fasting and postprandial profiles of blood glucose, insulin and lipids, and serum metabolome in growing pigs. Eight jugular-vein catheterized pigs (initial body weight, 37.4 kg; 4 months of age) were fed 2 diets containing 72% purified starch (EMS or waxy corn starch (control)) in a cross-over design for 7 days. On day 8, an 8-hour meal tolerance test (MTT) was performed with serial blood samplings. Besides biochemical analysis, serum was analysed for 201 metabolites through targeted mass spectrometry-based metabolomic approaches. Pigs fed the EMS diet showed increased (P<0.05) immediate serum insulin and plasma glucose response compared to pigs fed the control diet; however, area-under-the-curves for insulin and glucose were not different among diets. Results from MTT indicated reduced postprandial serum triglycerides with EMS versus control diet (P<0.05). Likewise, serum metabolome profiling identified characteristic changes in glycerophospholipid, lysophospholipids, sphingomyelins and amino acid metabolome profiles with EMS diet compared to control diet. Results showed rapid adaptations of blood metabolites to dietary starch shifts within 7 days. In conclusion, EMS ingestion showed potential to attenuate postprandial raise in serum lipids and suggested constant alteration in the synthesis or breakdown of sphingolipids and phospholipids which might be a health benefit of EMS consumption. Because serum insulin was not lowered, more research is warranted to reveal possible underlying mechanisms behind the observed changes in the profile of serum lipid metabolome in response to EMS consumption.

Dynamic control modification techniques in teleoperation of a flexible manipulator. M.S. Thesis

NASA Technical Reports Server (NTRS)

Magee, David Patrick

1991-01-01

The objective of this research is to reduce the end-point vibration of a large, teleoperated manipulator while preserving the usefulness of the system motion. A master arm is designed to measure desired joint angles as the user specifies a desired tip motion. The desired joint angles from the master arm are the inputs to an adaptive PD control algorithm that positions the end-point of the manipulator. As the user moves the tip of the master, the robot will vibrate at its natural frequencies which makes it difficult to position the end-point. To eliminate the tip vibration during teleoperated motions, an input shaping method is presented. The input shaping method transforms each sample of the desired input into a new set of impulses that do not excite the system resonances. The method is explained using the equation of motion for a simple, second-order system. The impulse response of such a system is derived and the constraint equations for vibrationless motion are presented. To evaluate the robustness of the method, a different residual vibration equation from Singer's is derived that more accurately represents the input shaping technique. The input shaping method is shown to actually increase the residual vibration in certain situations when the system parameters are not accurately specified. Finally, the implementation of the input shaping method to a system with varying parameters is shown to induce a vibration into the system. To eliminate this vibration, a modified command shaping technique is developed. The ability of the modified command shaping method to reduce vibration at the system resonances is tested by varying input perturbations to trajectories in a range of possible user inputs. By comparing the frequency responses of the transverse acceleration at the end-point of the manipulator, the modified method is compared to the original PD routine. The control scheme that produces the smaller magnitude of resonant vibration at the first natural frequency is considered the more effective control method.

Enzymatically Modified Starch Ameliorates Postprandial Serum Triglycerides and Lipid Metabolome in Growing Pigs

PubMed Central

Metzler-Zebeli, Barbara U.; Eberspächer, Eva; Grüll, Dietmar; Kowalczyk, Lidia; Molnar, Timea; Zebeli, Qendrim

2015-01-01

Developing host digestion-resistant starches to promote human health is of great research interest. Chemically modified starches (CMS) are widely used in processed foods and although the modification of the starch molecule allows specific reduction in digestibility, the metabolic effects of CMS have been less well described. This short-term study evaluated the impact of enzymatically modified starch (EMS) on fasting and postprandial profiles of blood glucose, insulin and lipids, and serum metabolome in growing pigs. Eight jugular-vein catheterized pigs (initial body weight, 37.4 kg; 4 months of age) were fed 2 diets containing 72% purified starch (EMS or waxy corn starch (control)) in a cross-over design for 7 days. On day 8, an 8-hour meal tolerance test (MTT) was performed with serial blood samplings. Besides biochemical analysis, serum was analysed for 201 metabolites through targeted mass spectrometry-based metabolomic approaches. Pigs fed the EMS diet showed increased (P<0.05) immediate serum insulin and plasma glucose response compared to pigs fed the control diet; however, area-under-the-curves for insulin and glucose were not different among diets. Results from MTT indicated reduced postprandial serum triglycerides with EMS versus control diet (P<0.05). Likewise, serum metabolome profiling identified characteristic changes in glycerophospholipid, lysophospholipids, sphingomyelins and amino acid metabolome profiles with EMS diet compared to control diet. Results showed rapid adaptations of blood metabolites to dietary starch shifts within 7 days. In conclusion, EMS ingestion showed potential to attenuate postprandial raise in serum lipids and suggested constant alteration in the synthesis or breakdown of sphingolipids and phospholipids which might be a health benefit of EMS consumption. Because serum insulin was not lowered, more research is warranted to reveal possible underlying mechanisms behind the observed changes in the profile of serum lipid metabolome in response to EMS consumption. PMID:26076487

Robust adaptive vibration control of a flexible structure.

PubMed

Khoshnood, A M; Moradi, H M

2014-07-01

Different types of L1 adaptive control systems show that using robust theories with adaptive control approaches has produced high performance controllers. In this study, a model reference adaptive control scheme considering robust theories is used to propose a practical control system for vibration suppression of a flexible launch vehicle (FLV). In this method, control input of the system is shaped from the dynamic model of the vehicle and components of the control input are adaptively constructed by estimating the undesirable vibration frequencies. Robust stability of the adaptive vibration control system is guaranteed by using the L1 small gain theorem. Simulation results of the robust adaptive vibration control strategy confirm that the effects of vibration on the vehicle performance considerably decrease without the loss of the phase margin of the system. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Optimal Control Modification for Robust Adaptation of Singularly Perturbed Systems with Slow Actuators

NASA Technical Reports Server (NTRS)

Nguyen, Nhan T.; Ishihara, Abraham; Stepanyan, Vahram; Boskovic, Jovan

2009-01-01

Recently a new optimal control modification has been introduced that can achieve robust adaptation with a large adaptive gain without incurring high-frequency oscillations as with the standard model-reference adaptive control. This modification is based on an optimal control formulation to minimize the L2 norm of the tracking error. The optimal control modification adaptive law results in a stable adaptation in the presence of a large adaptive gain. This study examines the optimal control modification adaptive law in the context of a system with a time scale separation resulting from a fast plant with a slow actuator. A singular perturbation analysis is performed to derive a modification to the adaptive law by transforming the original system into a reduced-order system in slow time. The model matching conditions in the transformed time coordinate results in increase in the feedback gain and modification of the adaptive law.

Application of Bounded Linear Stability Analysis Method for Metrics-Driven Adaptive Control

NASA Technical Reports Server (NTRS)

Bakhtiari-Nejad, Maryam; Nguyen, Nhan T.; Krishnakumar, Kalmanje

2009-01-01

This paper presents the application of Bounded Linear Stability Analysis (BLSA) method for metrics-driven adaptive control. The bounded linear stability analysis method is used for analyzing stability of adaptive control models, without linearizing the adaptive laws. Metrics-driven adaptive control introduces a notion that adaptation should be driven by some stability metrics to achieve robustness. By the application of bounded linear stability analysis method the adaptive gain is adjusted during the adaptation in order to meet certain phase margin requirements. Analysis of metrics-driven adaptive control is evaluated for a second order system that represents a pitch attitude control of a generic transport aircraft. The analysis shows that the system with the metrics-conforming variable adaptive gain becomes more robust to unmodeled dynamics or time delay. The effect of analysis time-window for BLSA is also evaluated in order to meet the stability margin criteria.

A Formalisation of Adaptable Pervasive Flows

NASA Astrophysics Data System (ADS)

Bucchiarone, Antonio; Lafuente, Alberto Lluch; Marconi, Annapaola; Pistore, Marco

Adaptable Pervasive Flows is a novel workflow-based paradigm for the design and execution of pervasive applications, where dynamic workflows situated in the real world are able to modify their execution in order to adapt to changes in their environment. In this paper, we study a formalisation of such flows by means of a formal flow language. More precisely, we define APFoL (Adaptable Pervasive Flow Language) and formalise its textual notation by encoding it in Blite, a formalisation of WS-BPEL. The encoding in Blite equips the language with a formal semantics and enables the use of automated verification techniques. We illustrate the approach with an example of a Warehouse Case Study.

Bi-Objective Optimal Control Modification Adaptive Control for Systems with Input Uncertainty

NASA Technical Reports Server (NTRS)

Nguyen, Nhan T.

2012-01-01

This paper presents a new model-reference adaptive control method based on a bi-objective optimal control formulation for systems with input uncertainty. A parallel predictor model is constructed to relate the predictor error to the estimation error of the control effectiveness matrix. In this work, we develop an optimal control modification adaptive control approach that seeks to minimize a bi-objective linear quadratic cost function of both the tracking error norm and predictor error norm simultaneously. The resulting adaptive laws for the parametric uncertainty and control effectiveness uncertainty are dependent on both the tracking error and predictor error, while the adaptive laws for the feedback gain and command feedforward gain are only dependent on the tracking error. The optimal control modification term provides robustness to the adaptive laws naturally from the optimal control framework. Simulations demonstrate the effectiveness of the proposed adaptive control approach.

Adaptive neural network motion control for aircraft under uncertainty conditions

NASA Astrophysics Data System (ADS)

Efremov, A. V.; Tiaglik, M. S.; Tiumentsev, Yu V.

2018-02-01

We need to provide motion control of modern and advanced aircraft under diverse uncertainty conditions. This problem can be solved by using adaptive control laws. We carry out an analysis of the capabilities of these laws for such adaptive systems as MRAC (Model Reference Adaptive Control) and MPC (Model Predictive Control). In the case of a nonlinear control object, the most efficient solution to the adaptive control problem is the use of neural network technologies. These technologies are suitable for the development of both a control object model and a control law for the object. The approximate nature of the ANN model was taken into account by introducing additional compensating feedback into the control system. The capabilities of adaptive control laws under uncertainty in the source data are considered. We also conduct simulations to assess the contribution of adaptivity to the behavior of the system.

Reward Improves Cancellation and Restraint Inhibition Across Childhood and Adolescence

PubMed Central

Sinopoli, Katia J.; Schachar, Russell; Dennis, Maureen

2011-01-01

Inhibitory control allows for the regulation of thought and action, and interacts with motivational variables, such as reward, to modify behavior adaptively as environments change. We examined the effects of reward on two distinct forms of inhibitory control, cancellation and restraint. Typically developing children and adolescents completed two versions of the stop signal task (cancellation and restraint) under three reward conditions (neutral, low reward, and high reward), where rewards were earned for successful inhibitory control. Rewards improved both cancellation and restraint inhibition, with similar effects of reward on each form of inhibitory control. Rewards did not alter the speed of response execution in either task, suggesting that rewards specifically altered inhibition processes without influencing processes related to response execution. Adolescents were faster and less variable than children when executing and inhibiting their responses. There were similar developmental effects of reward on the speed of inhibitory control, but group differences were found in terms of accuracy of inhibition in the restraint task. These results clarify how reward modulates two different forms of regulatory behavior in children and adolescents. PMID:21744952

Novel apparatus and methods for performing remotely controlled particle-solid interaction experiments at CERN

NASA Astrophysics Data System (ADS)

Krause, H. F.; Deveney, E. F.; Jones, N. L.; Vane, C. R.; Datz, S.; Knudsen, H.; Grafström, P.; Schuch, R.

1997-04-01

Recent atomic physics studies involving ultrarelativistic Pb ions required solid target positioners, scintillators, and a sophisticated data acquisition and control system placed in a remote location at the CERN Super Proton Synchrotron near Geneva, Switzerland. The apparatus, installed in a high-radiation zone underground, had to (i) function for months, (ii) automatically respond to failures such as power outages and particle-induced computer upsets, and (iii) communicate with the outside world via a telephone line. The heart of the apparatus developed was an Apple Macintosh-based CAMAC system that answered the telephone and interpreted and executed remote control commands that (i) sensed and set targets, (ii) controlled voltages and discriminator levels for scintillators, (iii) modified data acquisition hardware logic, (iv) reported control information, and (v) automatically synchronized data acquisition to the CERN spill cycle via a modem signal and transmitted experimental data to a remote computer. No problems were experienced using intercontinental telephone connections at 1200 baud. Our successful "virtual laboratory" approach that uses off-the-shelf electronics is generally adaptable to more conventional bench-type experiments.

Active vibration control of a full scale aircraft wing using a reconfigurable controller

NASA Astrophysics Data System (ADS)

Prakash, Shashikala; Renjith Kumar, T. G.; Raja, S.; Dwarakanathan, D.; Subramani, H.; Karthikeyan, C.

2016-01-01

This work highlights the design of a Reconfigurable Active Vibration Control (AVC) System for aircraft structures using adaptive techniques. The AVC system with a multichannel capability is realized using Filtered-X Least Mean Square algorithm (FxLMS) on Xilinx Virtex-4 Field Programmable Gate Array (FPGA) platform in Very High Speed Integrated Circuits Hardware Description Language, (VHDL). The HDL design is made based on Finite State Machine (FSM) model with Floating point Intellectual Property (IP) cores for arithmetic operations. The use of FPGA facilitates to modify the system parameters even during runtime depending on the changes in user's requirements. The locations of the control actuators are optimized based on dynamic modal strain approach using genetic algorithm (GA). The developed system has been successfully deployed for the AVC testing of the full-scale wing of an all composite two seater transport aircraft. Several closed loop configurations like single channel and multi-channel control have been tested. The experimental results from the studies presented here are very encouraging. They demonstrate the usefulness of the system's reconfigurability for real time applications.

Modified Sham Feeding of Sweet Solutions in Women with and without Bulimia Nervosa

PubMed Central

Klein, DA; Schebendach, JE; Brown, AJ; Smith, GP; Walsh, BT

2009-01-01

Although it is possible that binge eating in humans is due to increased responsiveness of orosensory excitatory controls of eating, there is no direct evidence for this because food ingested during a test meal stimulates both orosensory excitatory and postingestive inhibitory controls. To overcome this problem, we adapted the modified sham feeding technique (MSF) to measure the orosensory excitatory control of intake of a series of sweetened solutions. Previously published data showed the feasibility of a “sip-and-spit” procedure in nine healthy control women using solutions flavored with cherry Kool Aid® and sweetened with sucrose (0-20%)1. The current study extended this technique to measure the intake of artificially sweetened solutions in women with bulimia nervosa (BN) and in women with no history of eating disorders. Ten healthy women and 11 women with BN were randomly presented with cherry Kool Aid® solutions sweetened with five concentrations of aspartame (0, 0.01, 0.03, 0.08 and 0.28%) in a closed opaque container fitted with a straw. They were instructed to sip as much as they wanted of the solution during 1-minute trials and to spit the fluid out into another opaque container. Across all subjects, presence of sweetener increased intake (p<0.001). Women with BN sipped 40.5-53.1% more of all solutions than controls (p=0.03 for total intake across all solutions). Self-report ratings of liking, wanting and sweetness of solutions did not differ between groups. These results support the feasibility of a MSF procedure using artificially sweetened solutions, and the hypothesis that the orosensory stimulation of MSF provokes larger intake in women with BN than controls. PMID:18773914

Adaptive powertrain control for plugin hybrid electric vehicles

DOEpatents

Kedar-Dongarkar, Gurunath; Weslati, Feisel

2013-10-15

A powertrain control system for a plugin hybrid electric vehicle. The system comprises an adaptive charge sustaining controller; at least one internal data source connected to the adaptive charge sustaining controller; and a memory connected to the adaptive charge sustaining controller for storing data generated by the at least one internal data source. The adaptive charge sustaining controller is operable to select an operating mode of the vehicle's powertrain along a given route based on programming generated from data stored in the memory associated with that route. Further described is a method of adaptively controlling operation of a plugin hybrid electric vehicle powertrain comprising identifying a route being traveled, activating stored adaptive charge sustaining mode programming for the identified route and controlling operation of the powertrain along the identified route by selecting from a plurality of operational modes based on the stored adaptive charge sustaining mode programming.

L(sub 1) Adaptive Flight Control System: Flight Evaluation and Technology Transition

NASA Technical Reports Server (NTRS)

Xargay, Enric; Hovakimyan, Naira; Dobrokhodov, Vladimir; Kaminer, Isaac; Gregory, Irene M.; Cao, Chengyu

2010-01-01

Certification of adaptive control technologies for both manned and unmanned aircraft represent a major challenge for current Verification and Validation techniques. A (missing) key step towards flight certification of adaptive flight control systems is the definition and development of analysis tools and methods to support Verification and Validation for nonlinear systems, similar to the procedures currently used for linear systems. In this paper, we describe and demonstrate the advantages of L(sub l) adaptive control architectures for closing some of the gaps in certification of adaptive flight control systems, which may facilitate the transition of adaptive control into military and commercial aerospace applications. As illustrative examples, we present the results of a piloted simulation evaluation on the NASA AirSTAR flight test vehicle, and results of an extensive flight test program conducted by the Naval Postgraduate School to demonstrate the advantages of L(sub l) adaptive control as a verifiable robust adaptive flight control system.

Optimal control of nonlinear continuous-time systems in strict-feedback form.

PubMed

Zargarzadeh, Hassan; Dierks, Travis; Jagannathan, Sarangapani

2015-10-01

This paper proposes a novel optimal tracking control scheme for nonlinear continuous-time systems in strict-feedback form with uncertain dynamics. The optimal tracking problem is transformed into an equivalent optimal regulation problem through a feedforward adaptive control input that is generated by modifying the standard backstepping technique. Subsequently, a neural network-based optimal control scheme is introduced to estimate the cost, or value function, over an infinite horizon for the resulting nonlinear continuous-time systems in affine form when the internal dynamics are unknown. The estimated cost function is then used to obtain the optimal feedback control input; therefore, the overall optimal control input for the nonlinear continuous-time system in strict-feedback form includes the feedforward plus the optimal feedback terms. It is shown that the estimated cost function minimizes the Hamilton-Jacobi-Bellman estimation error in a forward-in-time manner without using any value or policy iterations. Finally, optimal output feedback control is introduced through the design of a suitable observer. Lyapunov theory is utilized to show the overall stability of the proposed schemes without requiring an initial admissible controller. Simulation examples are provided to validate the theoretical results.

Adaptation of Land-Use Demands to the Impact of Climate Change on the Hydrological Processes of an Urbanized Watershed

PubMed Central

Lin, Yu-Pin; Hong, Nien-Ming; Chiang, Li-Chi; Liu, Yen-Lan; Chu, Hone-Jay

2012-01-01

The adaptation of land-use patterns is an essential aspect of minimizing the inevitable impact of climate change at regional and local scales; for example, adapting watershed land-use patterns to mitigate the impact of climate change on a region’s hydrology. The objective of this study is to simulate and assess a region’s ability to adapt to hydrological changes by modifying land-use patterns in the Wu-Du watershed in northern Taiwan. A hydrological GWLF (Generalized Watershed Loading Functions) model is used to simulate three hydrological components, namely, runoff, groundwater and streamflow, based on various land-use scenarios under six global climate models. The land-use allocations are simulated by the CLUE-s model for the various development scenarios. The simulation results show that runoff and streamflow are strongly related to the precipitation levels predicted by different global climate models for the wet and dry seasons, but groundwater cycles are more related to land-use. The effects of climate change on groundwater and runoff can be mitigated by modifying current land-use patterns; and slowing the rate of urbanization would also reduce the impact of climate change on hydrological components. Thus, land-use adaptation on a local/regional scale provides an alternative way to reduce the impacts of global climate change on local hydrology. PMID:23202833

Adaptive Gain-based Stable Power Smoothing of a DFIG

DOE PAGES

Muljadi, Eduard; Lee, Hyewon; Hwang, Min; ...

2017-11-01

In a power system that has a high wind penetration, the output power fluctuation of a large-scale wind turbine generator (WTG) caused by the varying wind speed increases the maximum frequency deviation, which is an important metric to assess the quality of electricity, because of the reduced system inertia. This paper proposes a stable power-smoothing scheme of a doubly-fed induction generator (DFIG) that can suppress the maximum frequency deviation, particularly for a power system with a high wind penetration. To do this, the proposed scheme employs an additional control loop relying on the system frequency deviation that operates in combinationmore » with the maximum power point tracking control loop. To improve the power-smoothing capability while guaranteeing the stable operation of a DFIG, the gain of the additional loop is modified with the rotor speed and frequency deviation. The gain is set to be high if the rotor speed and/or frequency deviation is large. Here, the simulation results based on the IEEE 14-bus system demonstrate that the proposed scheme significantly lessens the output power fluctuation of a WTG under various scenarios by modifying the gain with the rotor speed and frequency deviation, and thereby it can regulate the frequency deviation within a narrow range.« less

Adaptive Gain-based Stable Power Smoothing of a DFIG

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

Muljadi, Eduard; Lee, Hyewon; Hwang, Min

In a power system that has a high wind penetration, the output power fluctuation of a large-scale wind turbine generator (WTG) caused by the varying wind speed increases the maximum frequency deviation, which is an important metric to assess the quality of electricity, because of the reduced system inertia. This paper proposes a stable power-smoothing scheme of a doubly-fed induction generator (DFIG) that can suppress the maximum frequency deviation, particularly for a power system with a high wind penetration. To do this, the proposed scheme employs an additional control loop relying on the system frequency deviation that operates in combinationmore » with the maximum power point tracking control loop. To improve the power-smoothing capability while guaranteeing the stable operation of a DFIG, the gain of the additional loop is modified with the rotor speed and frequency deviation. The gain is set to be high if the rotor speed and/or frequency deviation is large. Here, the simulation results based on the IEEE 14-bus system demonstrate that the proposed scheme significantly lessens the output power fluctuation of a WTG under various scenarios by modifying the gain with the rotor speed and frequency deviation, and thereby it can regulate the frequency deviation within a narrow range.« less

Effects of diversity on multiagent systems: Minority games

NASA Astrophysics Data System (ADS)

Wong, K. Y. Michael; Lim, S. W.; Gao, Zhuo

2005-06-01

We consider a version of large population games whose agents compete for resources using strategies with adaptable preferences. The games can be used to model economic markets, ecosystems, or distributed control. Diversity of initial preferences of strategies is introduced by randomly assigning biases to the strategies of different agents. We find that diversity among the agents reduces their maladaptive behavior. We find interesting scaling relations with diversity for the variance and other parameters such as the convergence time, the fraction of fickle agents, and the variance of wealth, illustrating their dynamical origin. When diversity increases, the scaling dynamics is modified by kinetic sampling and waiting effects. Analyses yield excellent agreement with simulations.

Material characterization and defect inspection in ultrasound images

NASA Astrophysics Data System (ADS)

Zmola, Carl; Segal, Andrew C.; Lovewell, Brian; Mahdavieh, Jacob; Ross, Joseph; Nash, Charles

1992-08-01

The use of ultrasonic imaging to analyze defects and characterize materials is critical in the development of non-destructive testing and non-destructive evaluation (NDT/NDE) tools for manufacturing. To develop better quality control and reliability in the manufacturing environment advanced image processing techniques are useful. For example, through the use of texture filtering on ultrasound images, we have been able to filter characteristic textures from highly textured C-scan images of materials. The materials have highly regular characteristic textures which are of the same resolution and dynamic range as other important features within the image. By applying texture filters and adaptively modifying their filter response, we have examined a family of filters for removing these textures.

Hysteresis compensation of piezoelectric deformable mirror based on Prandtl-Ishlinskii model

NASA Astrophysics Data System (ADS)

Ma, Jianqiang; Tian, Lei; Li, Yan; Yang, Zongfeng; Cui, Yuguo; Chu, Jiaru

2018-06-01

Hysteresis of piezoelectric deformable mirror (DM) reduces the closed-loop bandwidth and the open-loop correction accuracy of adaptive optics (AO) systems. In this work, a classical Prandtl-Ishlinskii (PI) model is employed to model the hysteresis behavior of a unimorph DM with 20 actuators. A modified control algorithm combined with the inverse PI model is developed for piezoelectric DMs. With the help of PI model, the hysteresis of the DM was reduced effectively from about 9% to 1%. Furthermore, open-loop regenerations of low-order aberrations with or without hysteresis compensation were carried out. The experimental results demonstrate that the regeneration accuracy with PI model compensation is significantly improved.

Time-delayed chameleon: Analysis, synchronization and FPGA implementation

NASA Astrophysics Data System (ADS)

Rajagopal, Karthikeyan; Jafari, Sajad; Laarem, Guessas

2017-12-01

In this paper we report a time-delayed chameleon-like chaotic system which can belong to different families of chaotic attractors depending on the choices of parameters. Such a characteristic of self-excited and hidden chaotic flows in a simple 3D system with time delay has not been reported earlier. Dynamic analysis of the proposed time-delayed systems are analysed in time-delay space and parameter space. A novel adaptive modified functional projective lag synchronization algorithm is derived for synchronizing identical time-delayed chameleon systems with uncertain parameters. The proposed time-delayed systems and the synchronization algorithm with controllers and parameter estimates are then implemented in FPGA using hardware-software co-simulation and the results are presented.

Heat exchange from the toucan bill reveals a controllable vascular thermal radiator.

PubMed

Tattersall, Glenn J; Andrade, Denis V; Abe, Augusto S

2009-07-24

The toco toucan (Ramphastos toco), the largest member of the toucan family, possesses the largest beak relative to body size of all birds. This exaggerated feature has received various interpretations, from serving as a sexual ornament to being a refined adaptation for feeding. However, it is also a significant surface area for heat exchange. Here we show the remarkable capacity of the toco toucan to regulate heat distribution by modifying blood flow, using the bill as a transient thermal radiator. Our results indicate that the toucan's bill is, relative to its size, one of the largest thermal windows in the animal kingdom, rivaling elephants' ears in its ability to radiate body heat.

Flight Validation of a Metrics Driven L(sub 1) Adaptive Control

NASA Technical Reports Server (NTRS)

Dobrokhodov, Vladimir; Kitsios, Ioannis; Kaminer, Isaac; Jones, Kevin D.; Xargay, Enric; Hovakimyan, Naira; Cao, Chengyu; Lizarraga, Mariano I.; Gregory, Irene M.

2008-01-01

The paper addresses initial steps involved in the development and flight implementation of new metrics driven L1 adaptive flight control system. The work concentrates on (i) definition of appropriate control driven metrics that account for the control surface failures; (ii) tailoring recently developed L1 adaptive controller to the design of adaptive flight control systems that explicitly address these metrics in the presence of control surface failures and dynamic changes under adverse flight conditions; (iii) development of a flight control system for implementation of the resulting algorithms onboard of small UAV; and (iv) conducting a comprehensive flight test program that demonstrates performance of the developed adaptive control algorithms in the presence of failures. As the initial milestone the paper concentrates on the adaptive flight system setup and initial efforts addressing the ability of a commercial off-the-shelf AP with and without adaptive augmentation to recover from control surface failures.

Direct adaptive control of manipulators in Cartesian space

NASA Technical Reports Server (NTRS)

Seraji, H.

1987-01-01

A new adaptive-control scheme for direct control of manipulator end effector to achieve trajectory tracking in Cartesian space is developed in this article. The control structure is obtained from linear multivariable theory and is composed of simple feedforward and feedback controllers and an auxiliary input. The direct adaptation laws are derived from model reference adaptive control theory and are not based on parameter estimation of the robot model. The utilization of adaptive feedforward control and the inclusion of auxiliary input are novel features of the present scheme and result in improved dynamic performance over existing adaptive control schemes. The adaptive controller does not require the complex mathematical model of the robot dynamics or any knowledge of the robot parameters or the payload, and is computationally fast for on-line implementation with high sampling rates. The control scheme is applied to a two-link manipulator for illustration.

Audio Adapted Assessment Data: Does the Addition of Audio to Written Items Modify the Item Calibration?

ERIC Educational Resources Information Center

Snyder, James

2010-01-01

This dissertation research examined the changes in item RIT calibration that occurred when adding audio to a set of currently calibrated RIT items and then placing these new items as field test items in the modified assessments on the NWEA MAP test platform. The researcher used test results from over 600 students in the Poway School District in…

Fabrication of Metal Nanoparticle-Modified Screen Printed Carbon Electrodes for the Evaluation of Hydrogen Peroxide Content in Teeth Whitening Strips

ERIC Educational Resources Information Center

Popa, Adriana; Abenojar, Eric C.; Vianna, Adam; Buenviaje, Czarina Y. A.; Yang, Jiahua; Pascual, Cherrie B.; Samia, Anna Cristina S.

2015-01-01

A laboratory experiment in which students synthesize Ag, Au, and Pt nanoparticles (NPs) and use them to modify screen printed carbon electrodes for the electroanalysis of the hydrogen peroxide content in commercially available teeth whitening strips is described. This experiment is designed for two 3-h laboratory periods and can be adapted for…

A novel joint-processing adaptive nonlinear equalizer using a modular recurrent neural network for chaotic communication systems.

PubMed

Zhao, Haiquan; Zeng, Xiangping; Zhang, Jiashu; Liu, Yangguang; Wang, Xiaomin; Li, Tianrui

2011-01-01

To eliminate nonlinear channel distortion in chaotic communication systems, a novel joint-processing adaptive nonlinear equalizer based on a pipelined recurrent neural network (JPRNN) is proposed, using a modified real-time recurrent learning (RTRL) algorithm. Furthermore, an adaptive amplitude RTRL algorithm is adopted to overcome the deteriorating effect introduced by the nesting process. Computer simulations illustrate that the proposed equalizer outperforms the pipelined recurrent neural network (PRNN) and recurrent neural network (RNN) equalizers. Copyright © 2010 Elsevier Ltd. All rights reserved.

Translation, adaptation and validation of the Western Ontario and McMaster Universities osteoarthritis index (WOMAC) for an Arab population: the Sfax modified WOMAC.

PubMed

Guermazi, Mohammad; Poiraudeau, Serge; Yahia, Monem; Mezganni, Monia; Fermanian, Jacques; Habib Elleuch, M; Revel, Michel

2004-06-01

To translate into Arabic and validate the Western Ontario and McMaster Universities (WOMAC) index. Arabic translation was obtained with use of the forward and backward translation method. Adaptations were made after a pilot study. Patients with symptomatic knee OA fulfilling the revised criteria of the American College of Rheumatology were included. Impairment outcome measures (pain as measured on a visual analog scale, the maximum distance walked, Kellgren's radiological score), Lequesne index score and Beck depression scale score were recorded. Each item was analyzed. Test-retest reliability was assessed with use of the intra-class correlation coefficient (ICC) and the Bland and Altman method. Construct validity was investigated with use of Spearman's rank correlation coefficient, and a factor analysis was performed. One hundred and three patients were included in the study. Eight questions of the WOMAC physical function subscale (PF) had insufficient psychometric properties and were excluded. Although test-retest reliability of the questionnaire was good (0.84, 0.84, and 0.92 for pain, stiffness, and modified PF subscales respectively), construct validity could not be demonstrated. Factor analysis of the modified form of the WOMAC extracted four factors, which differed from the a priori triple stratification. However, factor analysis of the modified PF subscales extracted two factors, which accounted for 68.4% of the total variance and could be clinically characterized (disability during activities requiring knee flexion within the first 90 degrees and activities requiring knee flexion over more than 90 degrees ). We translated and adapted the WOMAC index into Arabic to suit Tunisian people. The translated questionnaire is reliable but not valid in its original form. We propose the use of a modified version of PF subscale of the WOMAC, although the psychometric properties of this instrument must be examined in a larger population.

Adaptive control of dual-arm robots

NASA Technical Reports Server (NTRS)

Seraji, H.

1987-01-01

Three strategies for adaptive control of cooperative dual-arm robots are described. In the position-position control strategy, the adaptive controllers ensure that the end-effector positions of both arms track desired trajectories in Cartesian space despite unknown time-varying interaction forces exerted through the load. In the position-hybrid control strategy, the adaptive controller of one arm controls end-effector motions in the free directions and applied forces in the constraint directions, while the adaptive controller of the other arm ensures that the end-effector tracks desired position trajectories. In the hybrid-hybrid control strategy, the adaptive controllers ensure that both end-effectors track reference position trajectories while simultaneously applying desired forces on the load. In all three control strategies, the cross-coupling effects between the arms are treated as disturbances which are rejected by the adaptive controllers while following desired commands in a common frame of reference. The adaptive controllers do not require the complex mathematical model of the arm dynamics or any knowledge of the arm dynamic parameters or the load parameters such as mass and stiffness. The controllers have simple structures and are computationally fast for on-line implementation with high sampling rates.

The influence of the current intensity on the damping characteristics for a magneto-rheological damper of passenger car

NASA Astrophysics Data System (ADS)

Dobre, A.; Andreescu, C. N.; Stan, C.

2016-08-01

Due to their simplicity and controllability, adaptive dampers became very popular in automotive engineering industry, especially in the passenger cars industry, in spite of technological obstacles inherent and the high cost of the magnetic fluid. “MagneRide” is the first technology which uses smart fluids in the shock absorbers of the vehicles adaptive suspensions. Since the discovery of the magneto-rheological effect there is a consistent progress regarding the control algorithms and hardware part itself. These magneto-rheological devices have a major potential which can be explored in various fields of applications. At present many companies make researches for the improvement of the response time and for obtaining a better response at low frequency and amplitude of the body car oscillations. The main objective of this paper is to determine the damping characteristic of a magnetorheological shock absorber of a passenger car. The authors aim to observe how to modify the damping characteristic by changing the intensity of the electric current. The experimental researches have being carried out on a complex and modern test bench especially built for testing shock absorbers, in order to compare the damping characteristic of the classical damper with the magneto-rheological damper.

Species variation in the degree of sex differences in brain and behaviour related to birdsong: adaptations and constraints.

PubMed

Ball, Gregory F

2016-02-19

The song-control system, a neural circuit that controls the learning and production of birdsong, provided the first example in vertebrates of prominent macro-morphological sex differences in the brain. Forebrain nuclei HVC, robust nucleus of the arcopallium (RA) and area X all exhibit prominent male-biased sex differences in volume in zebra finches and canaries. Subsequent studies compared species that exhibited different degrees of a sex difference in song behaviour and revealed an overall positive correlation between male biases in song behaviour and male biases in the volume of the song nuclei. However, several exceptions have been described in which male biases in HVC and RA are observed even though song behaviour is equal or even female-biased. Other phenotypic measures exhibit lability in both sexes. In the duetting plain-tailed wren (Pheugopedius euophrys), males and females have auditory cells in the song system that are tuned to the joint song the two sexes produce rather than just male or female components. These findings suggest that there may be constraints on the adaptive response of the song system to ecological conditions as assessed by nucleus volume but that other critical variables regulating song can respond so that each sex can modify its song behaviour as needed. © 2016 The Author(s).

Investigation on active vibration isolation of a Stewart platform with piezoelectric actuators

NASA Astrophysics Data System (ADS)

Wang, Chaoxin; Xie, Xiling; Chen, Yanhao; Zhang, Zhiyi

2016-11-01

A Stewart platform with piezoelectric actuators is presented for micro-vibration isolation. The Jacobi matrix of the Stewart platform, which reveals the relationship between the position/pointing of the payload and the extensions of the six struts, is derived by kinematic analysis. The dynamic model of the Stewart platform is established by the FRF (frequency response function) synthesis method. In the active control loop, the direct feedback of integrated forces is combined with the FxLMS based adaptive feedback to dampen vibration of inherent modes and suppress transmission of periodic vibrations. Numerical simulations were conducted to prove vibration isolation performance of the Stewart platform under random and periodical disturbances, respectively. In the experiment, the output consistencies of the six piezoelectric actuators were measured at first and the theoretical Jacobi matrix as well as the feedback gain of each piezoelectric actuator was subsequently modified according to the measured consistencies. The direct feedback loop was adjusted to achieve sufficient active damping and the FxLMS based adaptive feedback control was adopted to suppress vibration transmission in the six struts. Experimental results have demonstrated that the Stewart platform can achieve 30 dB attenuation of periodical disturbances and 10-20 dB attenuation of random disturbances in the frequency range of 5-200 Hz.

Evaluating the Impact of EBP Education: Development of a Modified Fresno Test for Acute Care Nursing.

PubMed

Halm, Margo A

2018-05-14

Proficiency in evidence-based practice (EBP) is essential for relevant research findings to be integrated into clinical care when congruent with patient preferences. Few valid and reliable tools are available to evaluate the effectiveness of educational programs in advancing EBP attitudes, knowledge, skills, or behaviors, and ongoing competency. The Fresno test is one objective method to evaluate EBP knowledge and skills; however, the original and modified versions were validated with family physicians, physical therapists, and speech and language therapists. To adapt the Modified Fresno-Acute Care Nursing test and develop a psychometrically sound tool for use in academic and practice settings. In Phase 1, modified Fresno (Tilson, 2010) items were adapted for acute care nursing. In Phase 2, content validity was established with an expert panel. Content validity indices (I-CVI) ranged from .75 to 1.0. Scale CVI was .95%. A cross-sectional convenience sample of acute care nurses (n = 90) in novice, master, and expert cohorts completed the Modified Fresno-Acute Care Nursing test administered electronically via SurveyMonkey. Total scores were significantly different between training levels (p < .0001). Novice nurses scored significantly lower than master or expert nurses, but differences were not found between the latter cohorts. Total score reliability was acceptable: (interrater [ICC (2, 1)]) = .88. Cronbach's alpha was 0.70. Psychometric properties of most modified items were satisfactory; however, six require further revision and testing to meet acceptable standards. The Modified Fresno-Acute Care Nursing test is a 14-item test for objectively assessing EBP knowledge and skills of acute care nurses. While preliminary psychometric properties for this new EBP knowledge measure for acute care nursing are promising, further validation of some of the items and scoring rubric is needed. © 2018 Sigma Theta Tau International.

Cultural Continuity in an Educational Institution: A Case Study of the Suzuki Method of Music Instruction.

ERIC Educational Resources Information Center

Taniuchi, Lois

As the Suzuki method of music instruction has spread from Japan to other countries, its methods have been modified to adapt to the culture of those countries. In this paper the Japanese cultural background, and the principles and methods developed in Japan are discussed and compared with the adaptations made in the United States. The Suzuki method…

The Department of Defense and Climate Change: Initiating the Dialogue

DTIC Science & Technology

2012-01-01

that might be impacted: such as for wetlands, endangered species, and protected marine ecosystems and species. In addition, the rapid implementation...their adaptive capacity. As a result, continued improvements are needed in the representation of biotic and abiotic components of environmental...resilience? 3) What design features of DoD’s built infrastructure should be assessed and modified for improving their adaptive capacity to a

Adaptation of the Nelson-Somogyi reducing-sugar assay to a microassay using microtiter plates.

PubMed

Green, F; Clausen, C A; Highley, T L

1989-11-01

The Nelson-Somogyi assay for reducing sugars was adapted to microtiter plates. The primary advantages of this modified assay are (i) smaller sample and reagent volumes, (ii) elimination of boiling and filtration steps, (iii) automated measurement with a dual-wavelength scanning TLC densitometer, (iv) increased range and reproducibility, and (v) automated colorimetric readings by reflectance rather than absorbance.

Translating and culturally adapting the shortened version of the Hospital Ethical Climate Survey (HECS-S) - retaining or modifying validated instruments.

PubMed

Pergert, Pernilla; Bartholdson, Cecilia; Wenemark, Marika; Lützén, Kim; Af Sandeberg, Margareta

2018-05-10

The Hospital Ethical Climate Survey (HECS) was developed in the USA and later shortened (HECS-S). HECS has previously been translated into Swedish and the aim of this study was to describe a process of translating and culturally adapting HECS-S and to develop a Swedish multi-professional version, relevant for paediatrics. Another aim was to describe decisions about retaining versus modifying the questionnaire in order to keep the Swedish version as close as possible to the original while achieving a good functional level and trustworthiness. In HECS-S, the respondents are asked to indicate the veracity of statements. In HECS and HECS-S the labels of the scale range from 'almost never true' to 'almost always true'; while the Swedish HECS labels range from 'never' to 'always'. The procedure of translating and culturally adapting the Swedish version followed the scientific structure of guidelines. Three focus group interviews and three cognitive interviews were conducted with healthcare professionals. Furthermore, descriptive data were used from a previous study with healthcare professionals (n = 89), employing a modified Swedish HECS. Decisions on retaining or modifying items were made in a review group. The Swedish HECS-S consists of 21 items including all 14 items from HECS-S and items added to develop a multi-professional version, relevant for paediatrics. The descriptive data showed that few respondents selected 'never' and 'always'. To obtain a more even distribution of responses and keep Swedish HECS-S close to HECS-S, the original labels were retained. Linguistic adjustments were made to retain the intended meaning of the original items. The word 'respect' was used in HECS-S with two different meanings and was replaced in one of these because participants were concerned that respecting patients' wishes implied always complying with them. The process of developing a Swedish HECS-S included decisions on whether to retain or modify. Only minor adjustments were needed to achieve a good functional level and trustworthiness although some items needed to be added. Adjustments made could be used to also improve the English HECS-S. The results shed further light on the need to continuously evaluate even validated instruments and adapt them before use.

The Effect of Spaceflight on the Ultrastructure of the Cerebellum

NASA Technical Reports Server (NTRS)

Holstein, Gay R.; Martinelli, Giorgio P.

2003-01-01

In weightlessness, astronauts and cosmonauts may experience postural illusions as well as motion sickness symptoms known as the space adaptation syndrome. Upon return to Earth, they have irregularities in posture and balance. The adaptation to microgravity and subsequent re-adaptation to Earth occurs over several days. At the cellular level, a process called neuronal plasticity may mediate this adaptation. The term plasticity refers to the flexibility and modifiability in the architecture and functions of the nervous system. In fact, plastic changes are thought to underlie not just behavioral adaptation, but also the more generalized phenomena of learning and memory. The goal of this experiment was to identify some of the structural alterations that occur in the rat brain during the sensory and motor adaptation to microgravity. One brain region where plasticity has been studied extensively is the cerebellar cortex-a structure thought to be critical for motor control, coordination, the timing of movements, and, most relevant to the present experiment, motor learning. Also, there are direct as well as indirect connections between projections from the gravity-sensing otolith organs and several subregions of the cerebellum. We tested the hypothesis that alterations in the ultrastructural (the structure within the cell) architecture of rat cerebellar cortex occur during the early period of adaptation to microgravity, as the cerebellum adapts to the absence of the usual gravitational inputs. The results show ultrastructural evidence for neuronal plasticity in the central nervous system of adult rats after 24 hours of spaceflight. Qualitative studies conducted on tissue from the cerebellar cortex (specifically, the nodulus of the cerebellum) indicate that ultrastructural signs of plasticity are present in the cerebellar zones that receive input from the gravity-sensing organs in the inner ear (the otoliths). These changes are not observed in this region in cagematched ground control animals. The specific changes include the formation of lamellar bodies, profoundly enlarged Purkinje cell mitochondria, the presence of inter-neuronal cellular protrusions in the molecular layer, and signs of degeneration in the distal dendrites of the Purkinje cells. Since these morphologic signs are not apparent in the control animals, they are not likely to be due to caging or tissue processing effects. The particular nature of the structural alterations in the nodulus, most notably the formation of lamellar bodies and the presence of degeneration, further suggests that excitotoxicity (damaging overstimulation of neurons) may play a role in the short-term neural response to spaceflight. These findings suggest a structural basis for the neuronal and synaptic plasticity accompanying the central nervous system response to altered gravity and help identify the cellular bases underlying the vestibular abnormalities experienced by astronauts during periods of adaptation and re-adaptation to different gravitational forces. Also, since the short- and long-term changes in neural structure occurring during such periods of adaptation resemble the neuronal alterations that occur in some neurologic disorders such as stroke, these findings may offer guidance in the development of strategies for rehabilitation and treatment of such disorders.

Optimal Control Modification Adaptive Law for Time-Scale Separated Systems

NASA Technical Reports Server (NTRS)

Nguyen, Nhan T.

2010-01-01

Recently a new optimal control modification has been introduced that can achieve robust adaptation with a large adaptive gain without incurring high-frequency oscillations as with the standard model-reference adaptive control. This modification is based on an optimal control formulation to minimize the L2 norm of the tracking error. The optimal control modification adaptive law results in a stable adaptation in the presence of a large adaptive gain. This study examines the optimal control modification adaptive law in the context of a system with a time scale separation resulting from a fast plant with a slow actuator. A singular perturbation analysis is performed to derive a modification to the adaptive law by transforming the original system into a reduced-order system in slow time. A model matching conditions in the transformed time coordinate results in an increase in the actuator command that effectively compensate for the slow actuator dynamics. Simulations demonstrate effectiveness of the method.

Human Subthalamic Nucleus in Movement Error Detection and Its Evaluation during Visuomotor Adaptation

PubMed Central

Zavala, Baltazar; Pogosyan, Alek; Ashkan, Keyoumars; Zrinzo, Ludvic; Foltynie, Thomas; Limousin, Patricia; Brown, Peter

2014-01-01

Monitoring and evaluating movement errors to guide subsequent movements is a critical feature of normal motor control. Previously, we showed that the postmovement increase in electroencephalographic (EEG) beta power over the sensorimotor cortex reflects neural processes that evaluate motor errors consistent with Bayesian inference (Tan et al., 2014). Whether such neural processes are limited to this cortical region or involve the basal ganglia is unclear. Here, we recorded EEG over the cortex and local field potential (LFP) activity in the subthalamic nucleus (STN) from electrodes implanted in patients with Parkinson's disease, while they moved a joystick-controlled cursor to visual targets displayed on a computer screen. After movement offsets, we found increased beta activity in both local STN LFP and sensorimotor cortical EEG and in the coupling between the two, which was affected by both error magnitude and its contextual saliency. The postmovement increase in the coupling between STN and cortex was dominated by information flow from sensorimotor cortex to STN. However, an information drive appeared from STN to sensorimotor cortex in the first phase of the adaptation, when a constant rotation was applied between joystick inputs and cursor outputs. The strength of the STN to cortex drive correlated with the degree of adaption achieved across subjects. These results suggest that oscillatory activity in the beta band may dynamically couple the sensorimotor cortex and basal ganglia after movements. In particular, beta activity driven from the STN to cortex indicates task-relevant movement errors, information that may be important in modifying subsequent motor responses. PMID:25505327

Predation risk modifies behaviour by shaping the response of identified brain neurons.

PubMed

Magani, Fiorella; Luppi, Tomas; Nuñez, Jesus; Tomsic, Daniel

2016-04-15

Interpopulation comparisons in species that show behavioural variations associated with particular ecological disparities offer good opportunities for assessing how environmental factors may foster specific functional adaptations in the brain. Yet, studies on the neural substrate that can account for interpopulation behavioural adaptations are scarce. Predation is one of the strongest driving forces for behavioural evolvability and, consequently, for shaping structural and functional brain adaptations. We analysed the escape response of crabs ITALIC! Neohelice granulatafrom two isolated populations exposed to different risks of avian predation. Individuals from the high-risk area proved to be more reactive to visual danger stimuli (VDS) than those from an area where predators are rare. Control experiments indicate that the response difference was specific for impending visual threats. Subsequently, we analysed the response to VDS of a group of giant brain neurons that are thought to play a main role in the visually guided escape response of the crab. Neurons from animals of the population with the stronger escape response were more responsive to VDS than neurons from animals of the less reactive population. Our results suggest a robust linkage between the pressure imposed by the predation risk, the response of identified neurons and the behavioural outcome. © 2016. Published by The Company of Biologists Ltd.

Fast spacecraft adaptive attitude tracking control through immersion and invariance design

NASA Astrophysics Data System (ADS)

Wen, Haowei; Yue, Xiaokui; Li, Peng; Yuan, Jianping

2017-10-01

This paper presents a novel non-certainty-equivalence adaptive control method for the attitude tracking control problem of spacecraft with inertia uncertainties. The proposed immersion and invariance (I&I) based adaptation law provides a more direct and flexible approach to circumvent the limitations of the basic I&I method without employing any filter signal. By virtue of the adaptation high-gain equivalence property derived from the proposed adaptive method, the closed-loop adaptive system with a low adaptation gain could recover the high adaptation gain performance of the filter-based I&I method, and the resulting control torque demands during the initial transient has been significantly reduced. A special feature of this method is that the convergence of the parameter estimation error has been observably improved by utilizing an adaptation gain matrix instead of a single adaptation gain value. Numerical simulations are presented to highlight the various benefits of the proposed method compared with the certainty-equivalence-based control method and filter-based I&I control schemes.

Decentralized adaptive control

NASA Technical Reports Server (NTRS)

Oh, B. J.; Jamshidi, M.; Seraji, H.

1988-01-01

A decentralized adaptive control is proposed to stabilize and track the nonlinear, interconnected subsystems with unknown parameters. The adaptation of the controller gain is derived by using model reference adaptive control theory based on Lyapunov's direct method. The adaptive gains consist of sigma, proportional, and integral combination of the measured and reference values of the corresponding subsystem. The proposed control is applied to the joint control of a two-link robot manipulator, and the performance in computer simulation corresponds with what is expected in theoretical development.

Investigation of light-induced conformation changes in spiropyran-modified succinylated poly(L-lysine).

PubMed

Cooper, T M; Stone, M O; Natarajan, L V; Crane, R L

1995-08-01

To determine the maximum range of coupling between side-chain photochromism and polypeptide conformation change, we modified the carboxylate side chains of succinylated poly(L-lysine) with a spiropyran to form polypeptide I. The extent of modification was determined to be 35.5%. The spacer group length between the polypeptide alpha-carbon and the dye was 12 atoms, providing minimum polypeptide-dye interaction. Conformation changes were monitored by circular dichroism as a function of light adaptation and solvent composition (hexafluoroisopropanol [HFIP] vs trifluoroethanol [TFE]). Under all solvent compositions, the dark-adapted dye was in the merocyanine form. Light adaptation by visible light converted the dye to the spiropyran form. When dissolved in TFE, I adopted a helical conformation insensitive to light adaptation. With increasing percentage HFIP, a solvent-induced helix-to-coil transition was observed around 80% (vol/vol) HFIP. At 100% HFIP, both light- and dark-adapted forms of I were in the coil state. Near the midpoint of the solvent-induced helix-to-coil transition, light adaptation caused conformation changes. Applying helix-to-coil transition theory, we measured a statistically significant difference in coil segment-HFIP binding constant for light- vs dark-adapted solutions (6.38 +/- 0.03 M-1 vs 6.56 +/- 0.03 M-1), but not for the nucleation parameter sigma (1.2 +/- 0.4 10(-3) vs 1.3 +/- 0.3 x 10(-3). The small binding constant difference translated to a light-induced binding energy difference of 17 cal/mol/monomer. Near the midpoint of the helix-to-coil transition, collective interactions between monomer units made possible the translation of a small energy difference (less than RT) into large macromolecular conformation changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Multi-Time Step Service Restoration for Advanced Distribution Systems and Microgrids

DOE PAGES

Chen, Bo; Chen, Chen; Wang, Jianhui; ...

2017-07-07

Modern power systems are facing increased risk of disasters that can cause extended outages. The presence of remote control switches (RCSs), distributed generators (DGs), and energy storage systems (ESS) provides both challenges and opportunities for developing post-fault service restoration methodologies. Inter-temporal constraints of DGs, ESS, and loads under cold load pickup (CLPU) conditions impose extra complexity on problem formulation and solution. In this paper, a multi-time step service restoration methodology is proposed to optimally generate a sequence of control actions for controllable switches, ESSs, and dispatchable DGs to assist the system operator with decision making. The restoration sequence is determinedmore » to minimize the unserved customers by energizing the system step by step without violating operational constraints at each time step. The proposed methodology is formulated as a mixed-integer linear programming (MILP) model and can adapt to various operation conditions. Furthermore, the proposed method is validated through several case studies that are performed on modified IEEE 13-node and IEEE 123-node test feeders.« less

Multi-Time Step Service Restoration for Advanced Distribution Systems and Microgrids

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

Chen, Bo; Chen, Chen; Wang, Jianhui

Modern power systems are facing increased risk of disasters that can cause extended outages. The presence of remote control switches (RCSs), distributed generators (DGs), and energy storage systems (ESS) provides both challenges and opportunities for developing post-fault service restoration methodologies. Inter-temporal constraints of DGs, ESS, and loads under cold load pickup (CLPU) conditions impose extra complexity on problem formulation and solution. In this paper, a multi-time step service restoration methodology is proposed to optimally generate a sequence of control actions for controllable switches, ESSs, and dispatchable DGs to assist the system operator with decision making. The restoration sequence is determinedmore » to minimize the unserved customers by energizing the system step by step without violating operational constraints at each time step. The proposed methodology is formulated as a mixed-integer linear programming (MILP) model and can adapt to various operation conditions. Furthermore, the proposed method is validated through several case studies that are performed on modified IEEE 13-node and IEEE 123-node test feeders.« less

Adaptive Decentralized Control

DTIC Science & Technology

1985-04-01

and implementation of the decentralized controllers. It raises, however, many difficult questions regarding the conditions under which such a scheme ...adaptive controller, and a general form of the model reference adaptive controller (4]. We believe that this work represents a significant advance in the...Comparing the adaptive system with the tuned system results in the development of a generic adaptive error system. Passivity theory was used to derive

Training in cortical control of neuroprosthetic devices improves signal extraction from small neuronal ensembles.

PubMed

Helms Tillery, S I; Taylor, D M; Schwartz, A B

2003-01-01

We have recently developed a closed-loop environment in which we can test the ability of primates to control the motion of a virtual device using ensembles of simultaneously recorded neurons /29/. Here we use a maximum likelihood method to assess the information about task performance contained in the neuronal ensemble. We trained two animals to control the motion of a computer cursor in three dimensions. Initially the animals controlled cursor motion using arm movements, but eventually they learned to drive the cursor directly from cortical activity. Using a population vector (PV) based upon the relation between cortical activity and arm motion, the animals were able to control the cursor directly from the brain in a closed-loop environment, but with difficulty. We added a supervised learning method that modified the parameters of the PV according to task performance (adaptive PV), and found that animals were able to exert much finer control over the cursor motion from brain signals. Here we describe a maximum likelihood method (ML) to assess the information about target contained in neuronal ensemble activity. Using this method, we compared the information about target contained in the ensemble during arm control, during brain control early in the adaptive PV, and during brain control after the adaptive PV had settled and the animal could drive the cursor reliably and with fine gradations. During the arm-control task, the ML was able to determine the target of the movement in as few as 10% of the trials, and as many as 75% of the trials, with an average of 65%. This average dropped when the animals used a population vector to control motion of the cursor. On average we could determine the target in around 35% of the trials. This low percentage was also reflected in poor control of the cursor, so that the animal was unable to reach the target in a large percentage of trials. Supervised adjustment of the population vector parameters produced new weighting coefficients and directional tuning parameters for many neurons. This produced a much better performance of the brain-controlled cursor motion. It was also reflected in the maximum likelihood measure of cell activity, producing the correct target based only on neuronal activity in over 80% of the trials on average. The changes in maximum likelihood estimates of target location based on ensemble firing show that an animal's ability to regulate the motion of a cortically controlled device is not crucially dependent on the experimenter's ability to estimate intention from neuronal activity.

A modified adaptive algorithm of dealing with the high chirp when chirped pulses propagating in optical fiber

NASA Astrophysics Data System (ADS)

Wu, Lianglong; Fu, Xiquan; Guo, Xing

2013-03-01

In this paper, we propose a modified adaptive algorithm (MAA) of dealing with the high chirp to efficiently simulate the propagation of chirped pulses along an optical fiber for the propagation distance shorter than the "temporal focal length". The basis of the MAA is that the chirp term of initial pulse is treated as the rapidly varying part by means of the idea of the slowly varying envelope approximation (SVEA). Numerical simulations show that the performance of the MAA is validated, and that the proposed method can decrease the number of sampling points by orders of magnitude. In addition, the computational efficiency of the MAA compared with the time-domain beam propagation method (BPM) can be enhanced with the increase of the chirp of initial pulse.