Efficient Prolog memory management for flexible control strategies

1984 ◽  
Vol 2 (4) ◽  
pp. 361-369 ◽  
Author(s):  
David Scott Warren
Keyword(s):  
Memory Management ◽  
Control Strategies ◽  
Flexible Control

scholarly journals Online modification of goal-directed control in human reaching movements

2021 ◽  
Author(s):  
Antoine De Comite ◽  
Frédéric Crevecoeur ◽  
Philippe Lefèvre
Keyword(s):  
Control Strategies ◽  
Control Policy ◽  
Visual Display ◽  
Surface Emg ◽  
Movement Planning ◽  
Reaching Movements ◽  
Reaching Movement ◽  
Flexible Control ◽  
Task Goal ◽  
Sudden Appearance

Humans are able to perform very sophisticated reaching movements in a myriad of contexts based on flexible control strategies influenced by the task goal and environmental constraints such as obstacles. However, it remains unknown whether these control strategies can be adjusted online. The objective of this study was to determine whether the factors which determine control strategies during planning also modify the execution of an ongoing movement following sudden changes in task demand. More precisely, we investigated whether, and at which latency, feedback responses to perturbation loads followed the change in the structure of the goal target or environment. We changed the target width (square or rectangle) to alter the task redundancy, or the presence of obstacles to induce different constraints on the reach path, and assessed based on surface EMG recordings when the change in visual display altered the feedback response to mechanical perturbations. Task-related EMG responses were detected within 150 ms of a change in target shape. Considering visuomotor delays of ~ 100 ms, these results suggest that it takes 50 ms to change control policy within a trial. An additional 30 ms delay was observed when the change in context involved sudden appearance or disappearance of obstacles. Overall, our results demonstrate that the control policy within a reaching movement is not static: contextual factors which influence movement planning also influence movement execution at surprisingly short latencies. Moreover, the additional 30 ms associated with obstacles suggest that these two types of changes may be mediated via distinct processes.

Shutdown and Startup of a SOFC/GT Hybrid System

2006 ◽  
Author(s):  
Christoph Stiller ◽  
Bjo̸rn Thorud ◽  
Olav Bolland
Keyword(s):  
Hybrid System ◽  
Control Strategies ◽  
Inlet Temperature ◽  
Auxiliary Equipment ◽  
Detailed Model ◽  
Flexible Control ◽  
Oxygen Exposure ◽  
Low Load ◽  
Recuperative Heat Exchanger ◽  
And Control

During shutdown and startup trips, the SOFC/GT hybrid system and its components must be protected from critical incidents such as anode oxygen exposure, excessive temperature gradients and carbon deposition. A further task is to minimise the need for auxiliary equipment and resources. The paper shortly presents a previously published detailed model of a pressurised SOFC hybrid cycle for the analysis of transients and control strategies. Shutdown and startup procedures are proposed based on the possibility to use the GT system for temperature control of the SOFC. Air flow and SOFC system inlet temperature are controlled by using a combustion device upstream the turbine, turbine exhaust gas throttling and a variable bypass around the recuperative heat exchanger. During startup, a small amount of hydrogen for the ignition phase of the SOFC is used. A considerable nitrogen demand for anode flushing has been detected, though it is uncertain how much is required to safely protect the anode from oxygen exposure. In the simulation, shutdown takes app. 2 hours and startup takes app. 5.5 hours. It is, however, uncertain how quick temperature variations the SOFC can withstand. A more flexible control strategy would allow the system to follow a low load immediately after startup initiation by utilizing the gas turbine.

scholarly journals Online modification of goal-directed control in human reaching movements

2020 ◽  
Author(s):  
Antoine De Comite ◽  
Frédéric Crevecoeur ◽  
Philippe Lefèvre
Keyword(s):  
Control Strategies ◽  
Control Policy ◽  
Visual Display ◽  
Movement Planning ◽  
Reaching Movements ◽  
Planning Stage ◽  
Reaching Movement ◽  
Flexible Control ◽  
Task Goal ◽  
Sudden Appearance

AbstractHumans are able to perform very sophisticated reaching movements in a myriad of contexts based on flexible control strategies influenced by the task goal and environmental constraints such as obstacles. However, it remains unknown whether these control strategies can be adjusted online. The objective of this study was to determine whether the factors which determine control strategies during planning also modify the execution of an ongoing movement following sudden changes in task demand. More precisely, we investigated whether, and at which latency, feedback responses to perturbation loads followed the change in the structure of the goal target or environment. We changed the target width (square or rectangle) to alter the task redundancy, or the presence of obstacles to induce different constraints on the reach path, and assessed based on surface recordings when the change in visual display altered the feedback response to mechanical perturbations. Task-related EMG responses were detected within 150 ms of a change in target shape. Considering visuomotor delays of ∼ 100 ms, these results suggest that it takes 50 ms to change control policy within a trial. An additional 30 ms delay was observed when the change in context involved sudden appearance or disappearance of obstacles. Overall, our results demonstrate that the control policy within a reaching movement is not static: contextual factors which influence movement planning also influence movement execution at surprisingly short latencies. Moreover, the additional 30 ms associated with obstacles suggest that these two types of changes may be mediated via distinct processes.New & NoteworthyThe present work demonstrates that the control strategies used to perform reaching movements are adjusted online when the structure of the target or the presence of obstacles are altered during movements. Thus, the properties of goal-directed reaching control are not simply selected during the planning stage of a movement prior to execution. Rather, they are dynamically and rapidly adjusted online, within ∼150ms, according to changes in environment.

scholarly journals Vector-borne disease problems in rapid urbanization

QJM ◽  
2020 ◽  
Vol 113 (Supplement_1) ◽  
Author(s):  
A Zayed
Keyword(s):  
Control Strategies ◽  
Geographic Area ◽  
Disease Vectors ◽  
Continuous Change ◽  
Rapid Urbanization ◽  
Flexible Control ◽  
Vector Borne Diseases ◽  
Planning Decisions ◽  
Vector Borne ◽  
Change Vector

Abstract Habitat change of disease vectors has a great impact on their effectiveness to transmit vector borne diseases (VBD). This may result from man-made or natural factors. Urbanization, though it reflects development, is one crucial factor affecting the competence of existing vectors in certain geographic area, or allow for introducing and/or increasing the vectorial capacity of subsidiary vectors. Developing countries, challenging areas with political constrains and those affected by natural disasters are the most threatened areas in terms of VBD continuous change. Vector control strategies are mainly based on having an up-to-date complete knowledge of the spatial and temporal composition of disease vectors. Flexible control and planning decisions, and evidence-based interventions may help containing changes in VBD status due to the rapid urbanization.

scholarly journals Performance of the Priority Control Strategies for Bus Rapid Transit: Comparative Study from Scenario Microsimulation Using VISSIM

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Min Yang ◽  
Wei Wang ◽  
Bo Wang ◽  
Jing Han
Keyword(s):  
Control Strategies ◽  
Speed Control ◽  
Service Level ◽  
Simulation Software ◽  
Bus Rapid Transit ◽  
Base Case ◽  
Rapid Transit ◽  
Transit System ◽  
Flexible Control ◽  
Transit Speed

Bus rapid transit (BRT) has a great potential to improve the service level of transit system and has been implemented in many Chinese cities. However, the priority it can provide to buses has not been explored fully. Therefore, this study mainly investigated two advanced control strategies (signal priority using advanced detection and transit speed control). Signal priority using advanced detection is a strategy which detects one cycle ahead of buses’ arrival in order to adapt a more flexible control algorithm to provide signal priority for buses. Another is transit speed control, which provides priority at intersections for buses by controlling the speed of them and predicting their arrival at certain intersection. These two advanced strategies were modeled and evaluated using simulation software VISSIM and presented better performance than other three scenarios (base case, exclusive bus lane, and conventional transit signal priority). Only the eastbound direction would be researched as its traffic flow and bus volume are much larger than those of the other direction. Data used in this model was collected in Yingtan City. It is also shown that both the operation of BRT and the efficiency of private traffic can be much improved by applying the two strategies proposed above.

Sign in / Sign up

Export Citation Format

Share Document