Ergonomics and human factors in endoscopic surgery: a comparison of manual vs telerobotic simulation systems.

PubMed

Lee, E C; Rafiq, A; Merrell, R; Ackerman, R; Dennerlein, J T

2005-08-01

Minimally invasive surgical techniques expose surgeons to a variety of occupational hazards that may promote musculoskeletal disorders. Telerobotic systems for minimally invasive surgery may help to reduce these stressors. The objective of this study was to compare manual and telerobotic endoscopic surgery in terms of postural and mental stress. Thirteen participants with no experience as primary surgeons in endoscopic surgery performed a set of simulated surgical tasks using two different techniques--a telerobotic master--slave system and a manual endoscopic surgery system. The tasks consisted of passing a soft spherical object through a series of parallel rings, suturing along a line 5-cm long, running a 32-in ribbon, and cannulation. The Job Strain Index (JSI) and Rapid Upper Limb Assessment (RULA) were used to quantify upper extremity exposure to postural and force risk factors. Task duration was quantified in seconds. A questionnaire provided measures of the participants' intuitiveness and mental stress. The JSI and RULA scores for all four tasks were significantly lower for the telerobotic technique than for the manual one. Task duration was significantly longer for telerobotic than for manual tasks. Participants reported that the telerobotic technique was as intuitive as, and no more stressful than, the manual technique. Given identical tasks, the time to completion is longer using the telerobotic technique than its manual counterpart. For the given simulated tasks in the laboratory setting, the better scores for the upper extremity postural analysis indicate that telerobotic surgery provides a more comfortable environment for the surgeon without any additional mental stress.

Telerobotic management system: coordinating multiple human operators with multiple robots

NASA Astrophysics Data System (ADS)

King, Jamie W.; Pretty, Raymond; Brothers, Brendan; Gosine, Raymond G.

2003-09-01

This paper describes an application called the Tele-robotic management system (TMS) for coordinating multiple operators with multiple robots for applications such as underground mining. TMS utilizes several graphical interfaces to allow the user to define a partially ordered plan for multiple robots. This plan is then converted to a Petri net for execution and monitoring. TMS uses a distributed framework to allow robots and operators to easily integrate with the applications. This framework allows robots and operators to join the network and advertise their capabilities through services. TMS then decides whether tasks should be dispatched to a robot or a remote operator based on the services offered by the robots and operators.

Planning And Reasoning For A Telerobot

NASA Technical Reports Server (NTRS)

Peters, Stephen F.; Mittman, David S.; Collins, Carol E.; O'Meara Callahan, Jacquelyn S.; Rokey, Mark J.

1992-01-01

Document discusses research and development of Telerobot Interactive Planning System (TIPS). Goal in development of TIPS is to enable it to accept instructions from operator, then command run-time controller to execute operations to execute instructions. Challenges in transferring technology from testbed to operational system discussed.

Integrated Design of a Telerobotic Workstation

NASA Technical Reports Server (NTRS)

Rochlis, Jennifer L.; Clarke, John-Paul

2001-01-01

The experiments described in this paper are part of a larger joint MIT/NASA research effort that focuses on the development of a methodology for designing and evaluating integrated interfaces for highly dexterous and multi-functional telerobots. Specifically, a telerobotic workstation is being designed for an Extravehicular Activity (EVA) anthropomorphic space station telerobot. Previous researchers have designed telerobotic workstations based upon performance of discrete subsets of tasks (for example, peg-in-hole, tracking, etc.) without regard for transitions that operators go through between tasks performed sequentially in the context of larger integrated tasks. The exploratory research experiments presented here took an integrated approach and assessed how subjects operating a full-immersion telerobot perform during the transitions between sub-tasks of two common EVA tasks. Preliminary results show that up to 30% of total task time is spent gaining and maintaining Situation Awareness (SA) of their task space and environment during transitions. Although task performance improves over the two trial days, the percentage of time spent on SA remains the same. This method identifies areas where workstation displays and feedback mechanisms are most needed to increase operator performance and decrease operator workload - areas that previous research methods have not been able to address.

Advanced Robotics for In-Space Vehicle Processing

NASA Technical Reports Server (NTRS)

Smith, Jeffrey H.; Estus, Jay; Heneghan, Cate; Bosley, John

1990-01-01

An analysis of spaceborne vehicle processing is described. Generic crew-EVA tasks are presented for a specific vehicle, the orbital maneuvering vehicle (OMV), with general implications to other on-orbit vehicles. The OMV is examined with respect to both servicing and maintenance. Crew-EVA activities are presented by task and mapped to a common set of generic crew-EVA primitives to identify high-demand areas for telerobot services. Similarly, a set of telerobot primitives is presented that can be used to model telerobot actions for alternative telerobot reference configurations. The telerobot primitives are tied to technologies and used for composting telerobot operations for an automated refueling scenario. Telerobotics technology issues and design accomodation guidelines (hooks and scars) for the Space Station Freedom are described.

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.

Generic extravehicular (EVA) and telerobot task primitives for analysis, design, and integration. Version 1.0: Reference compilation for the EVA and telerobotics communities

NASA Technical Reports Server (NTRS)

Smith, Jeffrey H.; Drews, Michael

1990-01-01

The results are described of an effort to establish commonality and standardization of generic crew extravehicular (crew-EVA) and telerobotic task analysis primitives used for the study of spaceborne operations. Although direct crew-EVA plans are the most visible output of spaceborne operations, significant ongoing efforts by a wide variety of projects and organizations also require tools for estimation of crew-EVA and telerobotic times. Task analysis tools provide estimates for input to technical and cost tradeoff studies. A workshop was convened to identify the issues and needs to establish a common language and syntax for task analysis primitives. In addition, the importance of such a syntax was shown to have precedence over the level to which such a syntax is applied. The syntax, lists of crew-EVA and telerobotic primitives, and the data base in diskette form are presented.

Overview of the NASA automation and robotics research program

NASA Technical Reports Server (NTRS)

Holcomb, Lee; Larsen, Ron

1985-01-01

NASA studies over the last eight years have identified five opportunities for the application of automation and robotics technology: (1) satellite servicing; (2) system monitoring, control, sequencing and diagnosis; (3) space manufacturing; (4) space structure assembly; and (5) planetary rovers. The development of these opportunities entails two technology R&D thrusts: telerobotics and system autonomy; both encompass such concerns as operator interface, task planning and reasoning, control execution, sensing, and systems integration.

Spaceborne construction and operations planning - Decision rules for selecting EVA, telerobot, and combined work-systems

NASA Technical Reports Server (NTRS)

Smith, Jeffrey H.

1992-01-01

An approach is presented for selecting an appropriate work-system for performing construction and operations tasks by humans and telerobots. The decision to use extravehicular activity (EVA) performed by astronauts, extravehicular robotics (EVR), or a combination of EVA and EVR is determined by the ratio of the marginal costs of EVA, EVR, and IVA. The approach proposed here is useful for examining cost trade-offs between tasks and performing trade studies of task improvement techniques (human or telerobotic).

The effect of monocular target blur on simulated telerobotic manipulation

NASA Technical Reports Server (NTRS)

Liu, Andrew; Stark, Lawrence

1991-01-01

A simulation involving three types of telerobotic tasks that require information about the spatial position of objects is reported. This is similar to the results of psychophysical experiments examining the effect of blur on stereoacuity. It is suggested that other psychophysical experimental results could be used to predict operator performance for other telerobotic tasks. It is demonstrated that refractive errors in the helmet-mounted stereo display system can affect performance in the three types of telerobotic tasks. The results of two sets of experiments indicate that monocular target blur of two diopters or more degrades stereo display performance to the level of monocular displays. This indicates that moderate levels of visual degradation that affect the operator's stereoacuity may eliminate the performance advantage of stereo displays.

High level intelligent control of telerobotics systems

NASA Technical Reports Server (NTRS)

Mckee, James

1988-01-01

A high level robot command language is proposed for the autonomous mode of an advanced telerobotics system and a predictive display mechanism for the teleoperational model. It is believed that any such system will involve some mixture of these two modes, since, although artificial intelligence can facilitate significant autonomy, a system that can resort to teleoperation will always have the advantage. The high level command language will allow humans to give the robot instructions in a very natural manner. The robot will then analyze these instructions to infer meaning so that is can translate the task into lower level executable primitives. If, however, the robot is unable to perform the task autonomously, it will switch to the teleoperational mode. The time delay between control movement and actual robot movement has always been a problem in teleoperations. The remote operator may not actually see (via a monitor) the results of high actions for several seconds. A computer generated predictive display system is proposed whereby the operator can see a real-time model of the robot's environment and the delayed video picture on the monitor at the same time.

Space Station Human Factors: Designing a Human-Robot Interface

NASA Technical Reports Server (NTRS)

Rochlis, Jennifer L.; Clarke, John Paul; Goza, S. Michael

2001-01-01

The experiments described in this paper are part of a larger joint MIT/NASA research effort and focus on the development of a methodology for designing and evaluating integrated interfaces for highly dexterous and multifunctional telerobot. Specifically, a telerobotic workstation is being designed for an Extravehicular Activity (EVA) anthropomorphic space station telerobot called Robonaut. Previous researchers have designed telerobotic workstations based upon performance of discrete subsets of tasks (for example, peg-in-hole, tracking, etc.) without regard for transitions that operators go through between tasks performed sequentially in the context of larger integrated tasks. The experiments presented here took an integrated approach to describing teleoperator performance and assessed how subjects operating a full-immersion telerobot perform during fine position and gross position tasks. In addition, a Robonaut simulation was also developed as part of this research effort, and experimentally tested against Robonaut itself to determine its utility. Results show that subject performance of teleoperated tasks using both Robonaut and the simulation are virtually identical, with no significant difference between the two. These results indicate that the simulation can be utilized as both a Robonaut training tool, and as a powerful design platform for telepresence displays and aids.

TEJAS - TELEROBOTICS/EVA JOINT ANALYSIS SYSTEM VERSION 1.0

NASA Technical Reports Server (NTRS)

Drews, M. L.

1994-01-01

The primary objective of space telerobotics as a research discipline is the augmentation and/or support of extravehicular activity (EVA) with telerobotic activity; this allows increased emplacement of on-orbit assets while providing for their "in situ" management. Development of the requisite telerobot work system requires a well-understood correspondence between EVA and telerobotics that to date has been only partially established. The Telerobotics/EVA Joint Analysis Systems (TEJAS) hypermedia information system uses object-oriented programming to bridge the gap between crew-EVA and telerobotics activities. TEJAS Version 1.0 contains twenty HyperCard stacks that use a visual, customizable interface of icon buttons, pop-up menus, and relational commands to store, link, and standardize related information about the primitives, technologies, tasks, assumptions, and open issues involved in space telerobot or crew EVA tasks. These stacks are meant to be interactive and can be used with any database system running on a Macintosh, including spreadsheets, relational databases, word-processed documents, and hypermedia utilities. The software provides a means for managing volumes of data and for communicating complex ideas, relationships, and processes inherent to task planning. The stack system contains 3MB of data and utilities to aid referencing, discussion, communication, and analysis within the EVA and telerobotics communities. The six baseline analysis stacks (EVATasks, EVAAssume, EVAIssues, TeleTasks, TeleAssume, and TeleIssues) work interactively to manage and relate basic information which you enter about the crew-EVA and telerobot tasks you wish to analyze in depth. Analysis stacks draw on information in the Reference stacks as part of a rapid point-and-click utility for building scripts of specific task primitives or for any EVA or telerobotics task. Any or all of these stacks can be completely incorporated within other hypermedia applications, or they can be referenced as is, without requiring data to be transferred into any other database. TEJAS is simple to use and requires no formal training. Some knowledge of HyperCard is helpful, but not essential. All Help cards printed in the TEJAS User's Guide are part of the TEJAS Help Stack and are available from a pop-up menu any time you are using TEJAS. Specific stacks created in TEJAS can be exchanged between groups, divisions, companies, or centers for complete communication of fundamental information that forms the basis for further analyses. TEJAS runs on any Apple Macintosh personal computer with at least one megabyte of RAM, a hard disk, and HyperCard 1.21, or later version. TEJAS is a copyrighted work with all copyright vested in NASA. HyperCard and Macintosh are registered trademarks of Apple Computer, Inc.

The NASA/OAST telerobot testbed architecture

NASA Technical Reports Server (NTRS)

Matijevic, J. R.; Zimmerman, W. F.; Dolinsky, S.

1989-01-01

Through a phased development such as a laboratory-based research testbed, the NASA/OAST Telerobot Testbed provides an environment for system test and demonstration of the technology which will usefully complement, significantly enhance, or even replace manned space activities. By integrating advanced sensing, robotic manipulation and intelligent control under human-interactive supervision, the Testbed will ultimately demonstrate execution of a variety of generic tasks suggestive of space assembly, maintenance, repair, and telescience. The Testbed system features a hierarchical layered control structure compatible with the incorporation of evolving technologies as they become available. The Testbed system is physically implemented in a computing architecture which allows for ease of integration of these technologies while preserving the flexibility for test of a variety of man-machine modes. The development currently in progress on the functional and implementation architectures of the NASA/OAST Testbed and capabilities planned for the coming years are presented.

Undersea applications of dexterous robotics

NASA Technical Reports Server (NTRS)

Gittleman, Mark M.

1994-01-01

The revolution and application of dexterous robotics in the undersea energy production industry and how this mature technology has affected planned SSF dexterous robotic tasks are examined. Undersea telerobotics, or Remotely Operated Vehicles (ROV's), have evolved in design and use since the mid-1970s. Originally developed to replace commercial divers for both planned and unplanned tasks, they are now most commonly used to perform planned robotic tasks in all phases of assembly, inspection, and maintenance of undersea structures and installations. To accomplish these tasks, the worksites, the tasks themselves, and the tools are now engineered with both the telerobot's and the diver's capabilities in mind. In many cases, this planning has permitted a reduction in telerobot system complexity and cost. The philosophies and design practices that have resulted in the successful incorporation of telerobotics into the highly competitive and cost conscious offshore production industry have been largely ignored in the space community. Cases where these philosophies have been adopted or may be successfully adopted in the near future are explored.

Potential roles for EVA and telerobotics in a unified worksite

NASA Astrophysics Data System (ADS)

Akin, David; Howard, Russel D.

1993-02-01

Although telerobotics and extravehicular activity (EVA) are often portrayed as competitive approaches to space operations, ongoing research in the Space Systems Laboratory (SSL) has demonstrated the utility of cooperative roles in an integrated EVA/telerobotic work site. Working in the neutral buoyancy simulation environment, tests were performed on interactive roles or EVA subjects and telerobots in structural assembly and satellite servicing tasks. In the most elaborate of these tests to date, EVA subjects were assisted by the SSL's Beam Assembly Teleoperator (BAT) in several servicing tasks planned for Hubble Space Telescope, using the high-fidelity crew training article in the NASA Marshall Neutral Buoyancy Simulator. These tests revealed several shortcomings in the design of BAT for satellite servicing and demonstrated the utility of a free-flying or RMS-mounted telerobot for providing EVA crew assistance. This paper documents the past tests, including the use of free-flying telerobots to effect the rescue of a simulated incapacitated EVA subject, and details planned future efforts in this area, including the testing of a new telerobotic system optimized for the satellite servicing role, the development of dedicated telerobotic devices designed specifically for assisting EVA crew, and conceptual approaches to advanced EVA/telerobotic operations such as the Astronaut Operations Vehicle.

Monovision techniques for telerobots

NASA Technical Reports Server (NTRS)

Goode, P. W.; Carnils, K.

1987-01-01

The primary task of the vision sensor in a telerobotic system is to provide information about the position of the system's effector relative to objects of interest in its environment. The subtasks required to perform the primary task include image segmentation, object recognition, and object location and orientation in some coordinate system. The accomplishment of the vision task requires the appropriate processing tools and the system methodology to effectively apply the tools to the subtasks. The functional structure of the telerobotic vision system used in the Langley Research Center's Intelligent Systems Research Laboratory is discussed as well as two monovision techniques for accomplishing the vision subtasks.

Control strategies for a telerobot

NASA Technical Reports Server (NTRS)

Ohara, John; Stasi, Bill

1989-01-01

One of the major issues impacting the utility of telerobotic systems for space is the development of effective control strategies. For near-term applications, telerobot control is likely to utilize teleoperation methodologies with integrated supervisory control capabilities to assist the operator. Two different approaches to telerobotic control are evaluated: bilateral force reflecting master controllers and proportional rate six degrees-of-freedom hand controllers. The controllers' performance of single manipulator arm tasks is compared. Simultaneous operation of both manipulator arms and complex multiaxis slave arm movements is investigated. Task times are significantly longer and fewer errors are committed with the hand controllers. The hand controllers are also rated significantly higher in cognitive and manual control workload on the two-arm task. The master controllers are rated significantly higher in physical workload. The implications of these findings for space teleoperations and higher levels of control are discussed.

Proceedings of the Workshop on Space Telerobotics, volume 1

NASA Technical Reports Server (NTRS)

Rodriguez, G. (Editor)

1987-01-01

These proceedings report the results of a workshop on space telerobotics, which was held at the Jet Propulsion Laboratory, January 20-22, 1987. Sponsored by the NASA Office of Aeronautics and Space Technology (OAST), the Workshop reflected NASA's interest in developing new telerobotics technology for automating the space systems planned for the 1990s and beyond. The workshop provided a window into NASA telerobotics research, allowing leading researchers in telerobotics to exchange ideas on manipulation, control, system architectures, artificial intelligence, and machine sensing. One of the objectives was to identify important unsolved problems of current interest. The workshop consisted of surveys, tutorials, and contributed papers of both theoretical and practical interest. Several sessions were held on the themes of sensing and perception, control execution, operator interface, planning and reasoning, and system architecture.

Computational Virtual Reality (VR) as a human-computer interface in the operation of telerobotic systems

NASA Technical Reports Server (NTRS)

Bejczy, Antal K.

1995-01-01

This presentation focuses on the application of computer graphics or 'virtual reality' (VR) techniques as a human-computer interface tool in the operation of telerobotic systems. VR techniques offer very valuable task realization aids for planning, previewing and predicting robotic actions, operator training, and for visual perception of non-visible events like contact forces in robotic tasks. The utility of computer graphics in telerobotic operation can be significantly enhanced by high-fidelity calibration of virtual reality images to actual TV camera images. This calibration will even permit the creation of artificial (synthetic) views of task scenes for which no TV camera views are available.

Task oriented nonlinear control laws for telerobotic assembly operations

NASA Technical Reports Server (NTRS)

Walker, R. A.; Ward, L. S.; Elia, C. F.

1987-01-01

The goal of this research is to achieve very intelligent telerobotic controllers which are capable of receiving high-level commands from the human operator and implementing them in an adaptive manner in the object/task/manipulator workspace. Initiatives by the authors at Integrated Systems, Inc. to identify and develop the key technologies necessary to create such a flexible, highly programmable, telerobotic controller are presented. The focus of the discussion is on the modeling of insertion tasks in three dimensions and nonlinear implicit force feedback control laws which incorporate tool/workspace constraints. Preliminary experiments with dual arm beam assembly in 2-D are presented.

Telerobotic system performance measurement - Motivation and methods

NASA Technical Reports Server (NTRS)

Kondraske, George V.; Khoury, George J.

1992-01-01

A systems performance-based strategy for modeling and conducting experiments relevant to the design and performance characterization of telerobotic systems is described. A developmental testbed consisting of a distributed telerobotics network and initial efforts to implement the strategy described is presented. Consideration is given to the general systems performance theory (GSPT) to tackle human performance problems as a basis for: measurement of overall telerobotic system (TRS) performance; task decomposition; development of a generic TRS model; and the characterization of performance of subsystems comprising the generic model. GSPT employs a resource construct to model performance and resource economic principles to govern the interface of systems to tasks. It provides a comprehensive modeling/measurement strategy applicable to complex systems including both human and artificial components. Application is presented within the framework of a distributed telerobotics network as a testbed. Insight into the design of test protocols which elicit application-independent data is described.

Low level image processing techniques using the pipeline image processing engine in the flight telerobotic servicer

NASA Technical Reports Server (NTRS)

Nashman, Marilyn; Chaconas, Karen J.

1988-01-01

The sensory processing system for the NASA/NBS Standard Reference Model (NASREM) for telerobotic control is described. This control system architecture was adopted by NASA of the Flight Telerobotic Servicer. The control system is hierarchically designed and consists of three parallel systems: task decomposition, world modeling, and sensory processing. The Sensory Processing System is examined, and in particular the image processing hardware and software used to extract features at low levels of sensory processing for tasks representative of those envisioned for the Space Station such as assembly and maintenance are described.

The NASA automation and robotics technology program

NASA Technical Reports Server (NTRS)

Holcomb, Lee B.; Montemerlo, Melvin D.

1986-01-01

The development and objectives of the NASA automation and robotics technology program are reviewed. The objectives of the program are to utilize AI and robotics to increase the probability of mission success; decrease the cost of ground control; and increase the capability and flexibility of space operations. There is a need for real-time computational capability; an effective man-machine interface; and techniques to validate automated systems. Current programs in the areas of sensing and perception, task planning and reasoning, control execution, operator interface, and system architecture and integration are described. Programs aimed at demonstrating the capabilities of telerobotics and system autonomy are discussed.

Benchmarking Ada tasking on tightly coupled multiprocessor architectures

NASA Technical Reports Server (NTRS)

Collard, Philippe; Goforth, Andre; Marquardt, Matthew

1989-01-01

The development of benchmarks and performance measures for parallel Ada tasking is reported with emphasis on the macroscopic behavior of the benchmark across a set of load parameters. The application chosen for the study was the NASREM model for telerobot control, relevant to many NASA missions. The results of the study demonstrate the potential of parallel Ada in accomplishing the task of developing a control system for a system such as the Flight Telerobotic Servicer using the NASREM framework.

NASREN: Standard reference model for telerobot control

NASA Technical Reports Server (NTRS)

Albus, J. S.; Lumia, R.; Mccain, H.

1987-01-01

A hierarchical architecture is described which supports space station telerobots in a variety of modes. The system is divided into three hierarchies: task decomposition, world model, and sensory processing. Goals at each level of the task dedomposition heirarchy are divided both spatially and temporally into simpler commands for the next lower level. This decomposition is repreated until, at the lowest level, the drive signals to the robot actuators are generated. To accomplish its goals, task decomposition modules must often use information stored it the world model. The purpose of the sensory system is to update the world model as rapidly as possible to keep the model in registration with the physical world. The architecture of the entire control system hierarch is described and how it can be applied to space telerobot applications.

An expert system for planning and scheduling in a telerobotic environment

NASA Technical Reports Server (NTRS)

Ntuen, Celestine A.; Park, Eui H.

1991-01-01

A knowledge based approach to assigning tasks to multi-agents working cooperatively in jobs that require a telerobot in the loop was developed. The generality of the approach allows for such a concept to be applied in a nonteleoperational domain. The planning architecture known as the task oriented planner (TOP) uses the principle of flow mechanism and the concept of planning by deliberation to preserve and use knowledge about a particular task. The TOP is an open ended architecture developed with a NEXPERT expert system shell and its knowledge organization allows for indirect consultation at various levels of task abstraction. Considering that a telerobot operates in a hostile and nonstructured environment, task scheduling should respond to environmental changes. A general heuristic was developed for scheduling jobs with the TOP system. The technique is not to optimize a given scheduling criterion as in classical job and/or flow shop problems. For a teleoperation job schedule, criteria are situation dependent. A criterion selection is fuzzily embedded in the task-skill matrix computation. However, goal achievement with minimum expected risk to the human operator is emphasized.

Space Station Freedom coupling tasks: An evaluation of their space operational compatibility

NASA Technical Reports Server (NTRS)

Sampaio, Carlos E.; Bierschwale, John M.; Fleming, Terence F.; Stuart, Mark A.

1991-01-01

The development of the Space Station Freedom tasks that are compatible with both telerobotic as well as extravehicular activity is a necessary redundancy in order to insure successful day to day operation. One task to be routinely performed aboard Freedom will be the changeout of various quick disconnect fluid connectors. In an attempt to resolve these potentially contradictory issues of compatibility, mock-ups of couplings suitable to both extravehicular as well as telerobotic activity were designed and built. An evaluation performed at the Remote Operator Interaction Laboratory at NASA's Johnson Space Center is discussed, which assessed the prototype couplings as well as three standard coupling designs. Data collected during manual and telerobotic manipulation of the couplings indicated that the custom coupling was in fact shown to be faster to operate and generally preferred over the standard coupling designs.

Planning and reasoning in the JPL telerobot testbed

NASA Technical Reports Server (NTRS)

Peters, Stephen; Mittman, David; Collins, Carol; Omeara, Jacquie; Rokey, Mark

1990-01-01

The Telerobot Interactive Planning System is developed to serve as the highest autonomous-control level of the Telerobot Testbed. A recent prototype is described which integrates an operator interface for supervisory control, a task planner supporting disassembly and re-assembly operations, and a spatial planner for collision-free manipulator motion through the workspace. Each of these components is described in detail. Descriptions of the technical problem, approach, and lessons learned are included.

Flight telerobotic servicer legacy

NASA Astrophysics Data System (ADS)

Shattuck, Paul L.; Lowrie, James W.

1992-11-01

The Flight Telerobotic Servicer (FTS) was developed to enhance and provide a safe alternative to human presence in space. The first step for this system was a precursor development test flight (DTF-1) on the Space Shuttle. DTF-1 was to be a pathfinder for manned flight safety of robotic systems. The broad objectives of this mission were three-fold: flight validation of telerobotic manipulator (design, control algorithms, man/machine interfaces, safety); demonstration of dexterous manipulator capabilities on specific building block tasks; and correlation of manipulator performance in space with ground predictions. The DTF-1 system is comprised of a payload bay element (7-DOF manipulator with controllers, end-of-arm gripper and camera, telerobot body with head cameras and electronics module, task panel, and MPESS truss) and an aft flight deck element (force-reflecting hand controller, crew restraint, command and display panel and monitors). The approach used to develop the DTF-1 hardware, software and operations involved flight qualification of components from commercial, military, space, and R controller, end-of-arm tooling, force/torque transducer) and the development of the telerobotic system for space applications. The system is capable of teleoperation and autonomous control (advances state of the art); reliable (two-fault tolerance); and safe (man-rated). Benefits from the development flight included space validation of critical telerobotic technologies and resolution of significant safety issues relating to telerobotic operations in the Shuttle bay or in the vicinity of other space assets. This paper discusses the lessons learned and technology evolution that stemmed from developing and integrating a dexterous robot into a manned system, the Space Shuttle. Particular emphasis is placed on the safety and reliability requirements for a man-rated system as these are the critical factors which drive the overall system architecture. Other topics focused on include: task requirements and operational concepts for servicing and maintenance of space platforms; origins of technology for dexterous robotic systems; issues associated with space qualification of components; and development of the industrial base to support space robotics.

JPL space robotics: Present accomplishments and future thrusts

NASA Astrophysics Data System (ADS)

Weisbin, C. R.; Hayati, S. A.; Rodriguez, G.

1994-10-01

Complex missions require routine and unscheduled inspection for safe operation. The purpose of research in this task is to facilitate structural inspection of the planned Space Station while mitigating the need for extravehicular activity (EVA), and giving the operator supervisory control over detailed and somewhat mundane, but important tasks. The telerobotic system enables inspection relative to a given reference (e.g., the status of the facility at the time of the last inspection) and alerts the operator to potential anomalies for verification and action. There are two primary objectives of this project: (1) To develop technologies that enable well-integrated NASA ground-to-orbit telerobotics operations, and (2) to develop a prototype common architecture workstation which implements these capabilities for other NASA technology projects and planned NASA flight applications. This task develops and supports three telerobot control modes which are applicable to time delay operation: Preview teleoperation, teleprogramming, and supervised autonomy.

JPL space robotics: Present accomplishments and future thrusts

NASA Technical Reports Server (NTRS)

Weisbin, C. R.; Hayati, S. A.; Rodriguez, G.

1994-01-01

Complex missions require routine and unscheduled inspection for safe operation. The purpose of research in this task is to facilitate structural inspection of the planned Space Station while mitigating the need for extravehicular activity (EVA), and giving the operator supervisory control over detailed and somewhat mundane, but important tasks. The telerobotic system enables inspection relative to a given reference (e.g., the status of the facility at the time of the last inspection) and alerts the operator to potential anomalies for verification and action. There are two primary objectives of this project: (1) To develop technologies that enable well-integrated NASA ground-to-orbit telerobotics operations, and (2) to develop a prototype common architecture workstation which implements these capabilities for other NASA technology projects and planned NASA flight applications. This task develops and supports three telerobot control modes which are applicable to time delay operation: Preview teleoperation, teleprogramming, and supervised autonomy.

Ground controlled robotic assembly operations for Space Station Freedom

NASA Technical Reports Server (NTRS)

Parrish, Joseph C.

1991-01-01

A number of dextrous robotic systems and associated positioning and transportation devices are available on Space Station Freedom (SSF) to perform assembly tasks that would otherwise need to be performed by extravehicular activity (EVA) crewmembers. The currently planned operating mode for these robotic systems during the assembly phase is teleoperation by intravehicular activity (IVA) crewmembers. While this operating mode is less hazardous and expensive than manned EVA operations, and has insignificant control loop time delays, the amount of IVA time available to support telerobotic operations is much less than the anticipated requirements. Some alternative is needed to allow the robotic systems to perform useful tasks without exhausting the available IVA resources; ground control is one such alternative. The issues associated with ground control of SSF robotic systems to alleviate onboard crew time availability constraints are investigated. Key technical issues include the effect of communication time delays, the need for safe, reliable execution of remote operations, and required modifications to the SSF ground and flight system architecture. Time delay compensation techniques such as predictive displays and world model-based force reflection are addressed and collision detection and avoidance strategies to ensure the safety of the on-orbit crew, Orbiter, and SSF are described. Although more time consuming and difficult than IVA controlled teleoperations or manned EVA, ground controlled telerobotic operations offer significant benefits during the SSF assembly phase, and should be considered in assembly planning activities.

Usability testing of a mobile robotic system for in-home telerehabilitation.

PubMed

Boissy, Patrick; Brière, Simon; Corriveau, Hélène; Grant, Andrew; Lauria, Michel; Michaud, François

2011-01-01

Mobile robots designed to enhance telepresence in the support of telehealth services are being considered for numerous applications. TELEROBOT is a teleoperated mobile robotic platform equipped with videoconferencingcapabilities and designed to be used in a home environment to. In this study, learnability of the system's teleoperation interface and controls was evaluated with ten rehabilitation professionals during four training sessions in a laboratory environment and in an unknown home environment while performing the execution of a standardized evaluation protocol typically used in home care. Results show that the novice teleoperators' performances on two of the four metrics used (number of command and total time) improved significantly across training sessions (ANOVAS, p<0.05) and that performance in these metrics in the last training session reflected teleoperation abilities seen in the unknown home environment during navigation tasks (r=0,77 and 0,60). With only 4 hours of training, rehabilitation professionals were able learn to teleoperate successfully TELEROBOT. However teleoperation performances remained significantly less efficient then those of an expert. Under the home task condition (navigating the home environment from one point to the other as fast as possible) this translated to completion time between 350 seconds (best performance) and 850 seconds (worse performance). Improvements in other usability aspects of the system will be needed to meet the requirements of in-home telerehabilitation.

Plugfest 2009: Global Interoperability in Telerobotics and Telemedicine

PubMed Central

King, H. Hawkeye; Hannaford, Blake; Kwok, Ka-Wai; Yang, Guang-Zhong; Griffiths, Paul; Okamura, Allison; Farkhatdinov, Ildar; Ryu, Jee-Hwan; Sankaranarayanan, Ganesh; Arikatla, Venkata; Tadano, Kotaro; Kawashima, Kenji; Peer, Angelika; Schauß, Thomas; Buss, Martin; Miller, Levi; Glozman, Daniel; Rosen, Jacob; Low, Thomas

2014-01-01

Despite the great diversity of teleoperator designs and applications, their underlying control systems have many similarities. These similarities can be exploited to enable inter-operability between heterogeneous systems. We have developed a network data specification, the Interoperable Telerobotics Protocol, that can be used for Internet based control of a wide range of teleoperators. In this work we test interoperable telerobotics on the global Internet, focusing on the telesurgery application domain. Fourteen globally dispersed telerobotic master and slave systems were connected in thirty trials in one twenty four hour period. Users performed common manipulation tasks to demonstrate effective master-slave operation. With twenty eight (93%) successful, unique connections the results show a high potential for standardizing telerobotic operation. Furthermore, new paradigms for telesurgical operation and training are presented, including a networked surgery trainer and upper-limb exoskeleton control of micro-manipulators. PMID:24748993

Real-time, interactive, visually updated simulator system for telepresence

NASA Technical Reports Server (NTRS)

Schebor, Frederick S.; Turney, Jerry L.; Marzwell, Neville I.

1991-01-01

Time delays and limited sensory feedback of remote telerobotic systems tend to disorient teleoperators and dramatically decrease the operator's performance. To remove the effects of time delays, key components were designed and developed of a prototype forward simulation subsystem, the Global-Local Environment Telerobotic Simulator (GLETS) that buffers the operator from the remote task. GLETS totally immerses an operator in a real-time, interactive, simulated, visually updated artificial environment of the remote telerobotic site. Using GLETS, the operator will, in effect, enter into a telerobotic virtual reality and can easily form a gestalt of the virtual 'local site' that matches the operator's normal interactions with the remote site. In addition to use in space based telerobotics, GLETS, due to its extendable architecture, can also be used in other teleoperational environments such as toxic material handling, construction, and undersea exploration.

The effect of bandwidth on telerobot system performance

NASA Technical Reports Server (NTRS)

Uebel, Mark; Ali, Michael S.; Minis, Ioannis

1991-01-01

The purpose of the experiment was to determine the effect that various slave-joint bandwidths have on telerobot system performance. The telerobot system consisted of a slave arm controlled by a master. The slave incorporated an impedance loop to provide local compliance in addition to the compliance provided by the operator via force feedback. Three joint bandwidths, 0.5, 1.0, and 2.0 Hz, were used. The performance measures were the task completion time and the sums of the squared forces and moments exerted on the environment. The task consisted of peg-in-hole insertion and removal. The results of the experiment indicate a significant performance decrease at 0.5-Hz bandwidth relative to the 1- and 2-Hz bandwidths. There was no significant change in performance between the 1- and 2-Hz bandwidths.

Telerobotic research at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Sliwa, Nancy E.

1987-01-01

An overview of Automation Technology Branch facilities and research is presented. Manipulator research includes dual-arm coordination studies, space manipulator dynamics, end-effector controller development, automatic space structure assembly, and the development of a dual-arm master-slave telerobotic manipulator system. Sensor research includes gravity-compensated force control, real-time monovision techniques, and laser ranging. Artificial intelligence techniques are being explored for supervisory task control, collision avoidance, and connectionist system architectures. A high-fidelity dynamic simulation of robotic systems, ROBSIM, is being supported and extended. Cooperative efforts with Oak Ridge National Laboratory have verified the ability of teleoperators to perform complex structural assembly tasks, and have resulted in the definition of a new dual-arm master-slave telerobotic manipulator. A bibliography of research results and a list of technical contacts are included.

The flight telerobotic servicer Tinman concept: System design drivers and task analysis

NASA Technical Reports Server (NTRS)

Andary, J. F.; Hewitt, D. R.; Hinkal, S. W.

1989-01-01

A study was conducted to develop a preliminary definition of the Flight Telerobotic Servicer (FTS) that could be used to understand the operational concepts and scenarios for the FTS. Called the Tinman, this design concept was also used to begin the process of establishing resources and interfaces for the FTS on Space Station Freedom, the National Space Transportation System shuttle orbiter, and the Orbital Maneuvering vehicle. Starting with an analysis of the requirements and task capabilities as stated in the Phase B study requirements document, the study identified eight major design drivers for the FTS. Each of these design drivers and their impacts on the Tinman design concept are described. Next, the planning that is currently underway for providing resources for the FTS on Space Station Freedom is discussed, including up to 2000 W of peak power, up to four color video channels, and command and data rates up to 500 kbps between the telerobot and the control station. Finally, an example is presented to show how the Tinman design concept was used to analyze task scenarios and explore the operational capabilities of the FTS. A structured methodology using a standard terminology consistent with the NASA/National Bureau of Standards Standard Reference Model for Telerobot Control System Architecture (NASREM) was developed for this analysis.

The space station assembly phase: Flight telerobotic servicer feasibility, volume 1

NASA Technical Reports Server (NTRS)

Smith, Jeffrey H.; Gyamfi, Max A.; Volkmer, Kent; Zimmerman, Wayne F.

1987-01-01

The question is addressed which was raised by the Critical Evaluation Task Force (CETF) analysis of the space station: if a Flight Telerobotic Servicer (FTS) of a given technical risk could be built for use during space station assembly, could it save significant extravehicular (EVA) resources. Key issues and trade-offs associated with using an FTS to aid in space station assembly phase tasks such as construction and servicing are identified. A methodology is presented that incorporates assessment of candidate assembly phase tasks, telerobotics performance capabilities, development costs, operational constraints (STS and proximity operations), maintenance, attached payloads, and polar platforms. A discussion of the issues is presented with focus on potential FTS roles: (1) as a research-oriented test bed to learn more about space usage of telerobotics; (2) as a research-based test bed with an experimental demonstration orientation and limited assembly and servicing applications; or (3) as an operational system to augment EVA, to aid the construction of the space station, and to reduce the programmatic (schedule) risk by increasing the flexibility of mission operations. During the course of the study, the baseline configuration was modified into Phase 1 (a station assembled in 12 flights), and Phase 2 (a station assembled over a 30 flight period) configuration.

Robot geometry calibration

NASA Technical Reports Server (NTRS)

Hayati, Samad; Tso, Kam; Roston, Gerald

1988-01-01

Autonomous robot task execution requires that the end effector of the robot be positioned accurately relative to a reference world-coordinate frame. The authors present a complete formulation to identify the actual robot geometric parameters. The method applies to any serial link manipulator with arbitrary order and combination of revolute and prismatic joints. A method is also presented to solve the inverse kinematic of the actual robot model which usually is not a so-called simple robot. Experimental results performed by utilizing a PUMA 560 with simple measurement hardware are presented. As a result of this calibration a precision move command is designed and integrated into a robot language, RCCL, and used in the NASA Telerobot Testbed.

Terrestrial applications of NASA space telerobotics technologies

NASA Technical Reports Server (NTRS)

Lavery, Dave

1994-01-01

In 1985 the National Aeronautics and Space Administration (NASA) instituted a research program in telerobotics to develop and provide the technology for applications of telerobotics to the United States space program. The activities of the program are intended to most effectively utilize limited astronaut time by facilitating tasks such as inspection, assembly, repair, and servicing, as well as providing extended capability for remotely conducting planetary surface operations. As the program matured, it also developed a strong heritage of working with government and industry to directly transfer the developed technology into industrial applications.

Telerobot task planning and reasoning: Introduction to JPL artificial intelligence research

NASA Technical Reports Server (NTRS)

Atkinson, D. J.

1987-01-01

A view of the capabilities and areas of artificial intelligence research which are required for autonomous space telerobotics extending through the year 2000 is given. In the coming years, JPL will be conducting directed research to achieve these capabilities, as well as drawing heavily on collaborative efforts conducted with other research laboratories.

The space station assembly phase: System design trade-offs for the flight telerobotic servicer

NASA Technical Reports Server (NTRS)

Smith, Jeffrey H.; Gyamfi, Max; Volkmer, Kent; Zimmerman, Wayne

1988-01-01

The effects of a recent study aimed at identifying key issues and trade-offs associated with using a Flight Telerobotic Servicer (FTS) to aid in Space Station assembly-phase tasks is described. The use of automation and robotic (A and R) technologies for large space systems often involves a substitution of automation capabilities for human EVA or IVA activities. A methodology is presented that incorporates assessment of candidate assembly-phase tasks, telerobotic performance capabilities, development costs, and effects of operational constaints. Changes in the region of cost-effectiveness are examined under a variety of system design assumptions. A discussion of issues is presented with focus on three roles the FTS might serve: as a research-oriented test bed to learn more about space usage of telerobotics; as a research based test bed having an experimental demonstration orientation with limited assembly and servicing applications; or as an operational system to augment EVA and to aid construction of the Space Station and to reduce the program (schedule) risk by increasing the flexibility of mission operations.

Telerobotic control of a dextrous manipulator using master and six-DOF hand-controllers for space assembly and servicing tasks

NASA Technical Reports Server (NTRS)

O'Hara, John M.

1987-01-01

Two studies were conducted evaluating methods of controlling a telerobot; bilateral force reflecting master controllers and proportional rate six degrees of freedom (DOF) hand controllers. The first study compared the controllers on performance of single manipulator arm tasks, a peg-in-the-hole task, and simulated satellite orbital replacement unit changeout. The second study, a Space Station truss assembly task, required simultaneous operation of both manipulator arms (all 12 DOFs) and complex multiaxis slave arm movements. Task times were significantly longer and fewer errors were committed with the hand controllers. The hand controllers were also rated significantly higher in cognitive and manual control workload on the two-arm task. The master controllers were rated significantly higher in physical workload. There were no significant differences in ratings of manipulator control quality.

The flight telerobotic servicer and technology transfer

NASA Technical Reports Server (NTRS)

Andary, James F.; Bradford, Kayland Z.

1991-01-01

The Flight Telerobotic Servicer (FTS) project at the Goddard Space Flight Center is developing an advanced telerobotic system to assist in and reduce crew extravehicular activity (EVA) for Space Station Freedom (SSF). The FTS will provide a telerobotic capability in the early phases of the SSF program and will be employed for assembly, maintenance, and inspection applications. The current state of space technology and the general nature of the FTS tasks dictate that the FTS be designed with sophisticated teleoperational capabilities for its internal primary operating mode. However, technologies such as advanced computer vision and autonomous planning techniques would greatly enhance the FTS capabilities to perform autonomously in less structured work environments. Another objective of the FTS program is to accelerate technology transfer from research to U.S. industry.

Proceedings of the NASA Conference on Space Telerobotics, volume 4

NASA Technical Reports Server (NTRS)

Rodriguez, Guillermo (Editor); Seraji, Homayoun (Editor)

1989-01-01

Papers presented at the NASA Conference on Space Telerobotics are compiled. The theme of the conference was man-machine collaboration in space. The conference provided a forum for researchers and engineers to exchange ideas on the research and development required for the application of telerobotic technology to the space systems planned for the 1990's and beyond. Volume 4 contains papers related to the following subject areas: manipulator control; telemanipulation; flight experiments (systems and simulators); sensor-based planning; robot kinematics, dynamics, and control; robot task planning and assembly; and research activities at the NASA Langley Research Center.

Applying Behavior-Based Robotics Concepts to Telerobotic Use of Power Tooling

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

Noakes, Mark W; Hamel, Dr. William R.

While it has long been recognized that telerobotics has potential advantages to reduce operator fatigue, to permit lower skilled operators to function as if they had higher skill levels, and to protect tools and manipulators from excessive forces during operation, relatively little laboratory research in telerobotics has actually been implemented in fielded systems. Much of this has to do with the complexity of the implementation and its lack of ability to operate in complex unstructured remote systems environments. One possible solution is to approach the tooling task using an adaptation of behavior-based techniques to facilitate task decomposition to a simplermore » perspective and to provide sensor registration to the task target object in the field. An approach derived from behavior-based concepts has been implemented to provide automated tool operation for a teleoperated manipulator system. The generic approach is adaptable to a wide range of typical remote tools used in hot-cell and decontamination and dismantlement-type operations. Two tasks are used in this work to test the validity of the concept. First, a reciprocating saw is used to cut a pipe. The second task is bolt removal from mockup process equipment. This paper explains the technique, its implementation, and covers experimental data, analysis of results, and suggestions for implementation on fielded systems.« less

A methodology for automation and robotics evaluation applied to the space station telerobotic servicer

NASA Technical Reports Server (NTRS)

Smith, Jeffrey H.; Gyanfi, Max; Volkmer, Kent; Zimmerman, Wayne

1988-01-01

The efforts of a recent study aimed at identifying key issues and trade-offs associated with using a Flight Telerobotic Servicer (FTS) to aid in Space Station assembly-phase tasks is described. The use of automation and robotic (A and R) technologies for large space systems would involve a substitution of automation capabilities for human extravehicular or intravehicular activities (EVA, IVA). A methodology is presented that incorporates assessment of candidate assembly-phase tasks, telerobotic performance capabilities, development costs, and effect of operational constraints (space transportation system (STS), attached payload, and proximity operations). Changes in the region of cost-effectiveness are examined under a variety of systems design assumptions. A discussion of issues is presented with focus on three roles the FTS might serve: (1) as a research-oriented testbed to learn more about space usage of telerobotics; (2) as a research based testbed having an experimental demonstration orientation with limited assembly and servicing applications; or (3) as an operational system to augment EVA and to aid the construction of the Space Station and to reduce the programmatic (schedule) risk by increasing the flexibility of mission operations.

The space station assembly phase: Flight telerobotic servicer feasibility. Volume 2: Methodology and case study

NASA Technical Reports Server (NTRS)

Smith, Jeffrey H.; Gyamfi, Max A.; Volkmer, Kent; Zimmerman, Wayne F.

1987-01-01

A methodology is described for examining the feasibility of a Flight Telerobotic Servicer (FTS) using two assembly scenarios, defined at the EVA task level, for the 30 shuttle flights (beginning with MB-1) over a four-year period. Performing all EVA tasks by crew only is compared to a scenario in which crew EVA is augmented by FTS. A reference FTS concept is used as a technology baseline and life-cycle cost analysis is performed to highlight cost tradeoffs. The methodology, procedure, and data used to complete the analysis are documented in detail.

Dual Arm Work Package performance estimates and telerobot task network simulation

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

Draper, J.V.; Blair, L.M.

1997-02-01

This paper describes the methodology and results of a network simulation study of the Dual Arm Work Package (DAWP), to be employed for dismantling the Argonne National Laboratory CP-5 reactor. The development of the simulation model was based upon the results of a task analysis for the same system. This study was performed by the Oak Ridge National Laboratory (ORNL), in the Robotics and Process Systems Division. Funding was provided the US Department of Energy`s Office of Technology Development, Robotics Technology Development Program (RTDP). The RTDP is developing methods of computer simulation to estimate telerobotic system performance. Data were collectedmore » to provide point estimates to be used in a task network simulation model. Three skilled operators performed six repetitions of a pipe cutting task representative of typical teleoperation cutting operations.« less

Design of a structural and functional hierarchy for planning and control of telerobotic systems

NASA Technical Reports Server (NTRS)

Acar, Levent; Ozguner, Umit

1989-01-01

Hierarchical structures offer numerous advantages over conventional structures for the control of telerobotic systems. A hierarchically organized system can be controlled via undetailed task assignments and can easily adapt to changing circumstances. The distributed and modular structure of these systems also enables fast response needed in most telerobotic applications. On the other hand, most of the hierarchical structures proposed in the literature are based on functional properties of a system. These structures work best for a few given functions of a large class of systems. In telerobotic applications, all functions of a single system needed to be explored. This approach requires a hierarchical organization based on physical properties of a system and such a hierarchical organization is introduced. The decomposition, organization, and control of the hierarchical structure are considered, and a system with two robot arms and a camera is presented.

Evaluation of telerobotic systems using an instrumented task board

NASA Technical Reports Server (NTRS)

Carroll, John D.; Gierow, Paul A.; Bryan, Thomas C.

1991-01-01

An instrumented task board was developed at NASA Marshall Space Flight Center (MSFC). An overview of the task board design, and current development status is presented. The task board was originally developed to evaluate operator performance using the Protoflight Manipulator Arm (PFMA) at MSFC. The task board evaluates tasks for Orbital Replacement Unit (ORU), fluid connect and transfers, electrical connect/disconnect, bolt running, and other basic tasks. The instrumented task board measures the 3-D forces and torques placed on the board, determines the robot arm's 3-D position relative to the task board using IR optics, and provides the information in real-time. The PFMA joint input signals can also be measured from a breakout box to evaluate the sensitivity or response of the arm operation to control commands. The data processing system provides the capability for post processing of time-history graphics and plots of the PFMA positions, the operator's actions, and the PFMA servo reactions in addition to real-time force/torque data presentation. The instrumented task board's most promising use is developing benchmarks for NASA centers for comparison and evaluation of telerobotic performance.

FTS evolution

NASA Technical Reports Server (NTRS)

Provost, David E.

1990-01-01

Viewgraphs on flight telerobotic servicer evolution are presented. Topics covered include: paths for FTS evolution; frequently performed actions; primary task states; EPS radiator panel installation; generic task definitions; path planning; non-contact alignment; contact planning and control; and human operator interface.

The Flight Telerobotic Servicer (FTS) - A focus for automation and robotics on the Space Station

NASA Technical Reports Server (NTRS)

Hinkal, Sanford W.; Andary, James F.; Watzin, James G.; Provost, David E.

1987-01-01

The concept, fundamental design principles, and capabilities of the FTS, a multipurpose telerobotic system for use on the Space Station and Space Shuttle, are discussed. The FTS is intended to assist the crew in the performance of extravehicular tasks; the telerobot will also be used on the Orbital Maneuvering Vehicle to service free-flyer spacecraft. The FTS will be capable of both teleoperation and autonomous operation; eventually it may also utilize ground control. By careful selection of the functional architecture and a modular approach to the hardware and software design, the FTS can accept developments in artificial intelligence and newer, more advanced sensors, such as machine vision and collision avoidance.

Hierarchical Ada robot programming system (HARPS)- A complete and working telerobot control system based on the NASREM model

NASA Technical Reports Server (NTRS)

Leake, Stephen; Green, Tom; Cofer, Sue; Sauerwein, Tim

1989-01-01

HARPS is a telerobot control system that can perform some simple but useful tasks. This capability is demonstrated by performing the ORU exchange demonstration. HARPS is based on NASREM (NASA Standard Reference Model). All software is developed in Ada, and the project incorporates a number of different CASE (computer-aided software engineering) tools. NASREM was found to be a valid and useful model for building a telerobot control system. Its hierarchical and distributed structure creates a natural and logical flow for implementing large complex robust control systems. The ability of Ada to create and enforce abstraction enhanced the implementation of such control systems.

Telerobotic hand controller study of force reflection with position control mode

NASA Technical Reports Server (NTRS)

Willshire, Kelli F.; Hankins, Walter W.; Morris, A. Terry; Mixon, Randolph W.

1992-01-01

To gain further information about the effectiveness of kinesthetic force feedback or force reflection in position control mode for a telerobot, two Space Station related tasks were performed by eight subjects with and without the use of force reflection. Both time and subjective responses were measured. No differences due to force were found, however, other differences were found, e.g., gender. Comparisons of these results with other studies are discussed.

Wrist Camera Orientation for Effective Telerobotic Orbital Replaceable Unit (ORU) Changeout

NASA Technical Reports Server (NTRS)

Jones, Sharon Monica; Aldridge, Hal A.; Vazquez, Sixto L.

1997-01-01

The Hydraulic Manipulator Testbed (HMTB) is the kinematic replica of the Flight Telerobotic Servicer (FTS). One use of the HMTB is to evaluate advanced control techniques for accomplishing robotic maintenance tasks on board the Space Station. Most maintenance tasks involve the direct manipulation of the robot by a human operator when high-quality visual feedback is important for precise control. An experiment was conducted in the Systems Integration Branch at the Langley Research Center to compare several configurations of the manipulator wrist camera for providing visual feedback during an Orbital Replaceable Unit changeout task. Several variables were considered such as wrist camera angle, camera focal length, target location, lighting. Each study participant performed the maintenance task by using eight combinations of the variables based on a Latin square design. The results of this experiment and conclusions based on data collected are presented.

Execution of robot-assisted biopsies within the clinical context.

PubMed

Rovetta, A; Sala, R

1995-01-01

This paper describes the first prostatic biopsy on a human patient using a robotic and telerobotic system. This system was designed at the Politecnico di Milano, and the biopsy was performed on April 7, 1995, in the Hospital Policlinico in Milan, Italy.

A helmet mounted display to adapt the telerobotic environment to human vision

NASA Technical Reports Server (NTRS)

Tharp, Gregory; Liu, Andrew; Yamashita, Hitomi; Stark, Lawrence

1990-01-01

A Helmet Mounted Display system has been developed. It provides the capability to display stereo images with the viewpoint tied to subjects' head orientation. The type of display might be useful in a telerobotic environment provided the correct operating parameters are known. The effects of update frequency were tested using a 3D tracking task. The effects of blur were tested using both tracking and pick-and-place tasks. For both, researchers found that operator performance can be degraded if the correct parameters are not used. Researchers are also using the display to explore the use of head movements as part of gaze as subjects search their visual field for target objects.

The human factors of workstation telepresence

NASA Technical Reports Server (NTRS)

Smith, Thomas J.; Smith, Karl U.

1990-01-01

The term workstation telepresence has been introduced to describe human-telerobot compliance, which enables the human operator to effectively project his/her body image and behavioral skills to control of the telerobot itself. Major human-factors considerations for establishing high fidelity workstation telepresence during human-telerobot operation are discussed. Telerobot workstation telepresence is defined by the proficiency and skill with which the operator is able to control sensory feedback from direct interaction with the workstation itself, and from workstation-mediated interaction with the telerobot. Numerous conditions influencing such control have been identified. This raises the question as to what specific factors most critically influence the realization of high fidelity workstation telepresence. The thesis advanced here is that perturbations in sensory feedback represent a major source of variability in human performance during interactive telerobot operation. Perturbed sensory feedback research over the past three decades has established that spatial transformations or temporal delays in sensory feedback engender substantial decrements in interactive task performance, which training does not completely overcome. A recently developed social cybernetic model of human-computer interaction can be used to guide this approach, based on computer-mediated tracking and control of sensory feedback. How the social cybernetic model can be employed for evaluating the various modes, patterns, and integrations of interpersonal, team, and human-computer interactions which play a central role is workstation telepresence are discussed.

The space station freedom flight telerobotic servicer. The design and evolution of a dexterous space robot

NASA Astrophysics Data System (ADS)

McCain, Harry G.; Andary, James F.; Hewitt, Dennis R.; Haley, Dennis C.

The Flight Telerobotic Servicer (FTS) Project at the Goddard Space Flight Center is developing an advanced telerobotic system to assist in and reduce crew extravehicular activity (EVA) for Space Station Freedom (SSF). The FTS will provide a telerobotic capability to the Freedom Station in the early assembly phases of the program and will be employed for assembly, maintenance, and inspection applications throughout the lifetime of the space station. Appropriately configured elements of the FTS will also be employed for robotic manipulation in remote satellite servicing applications and possibly the Lunar/Mars Program. In mid-1989, the FTS entered the flight system design and implementation phase (Phase C/D) of development with the signing of the FTS prime contract with Martin Marietta Astronautics Group in Denver, Colorado. The basic FTS design is now established and can be reported on in some detail. This paper will describe the FTS flight system design and the rationale for the specific design approaches and component selections. The current state of space technology and the general nature of the FTS task dictate that the FTS be designed with sophisticated teleoperation capabilities for its initial primary operating mode. However, there are technologies, such as advanced computer vision and autonomous planning techniques currently in research and advanced development phases which would greatly enhance the FTS capabilities to perform autonomously in less structured work environments. Therefore, a specific requirement on the initial FTS design is that it has the capability to evolve as new technology becomes available. This paper will describe the FTS design approach for evolution to more autonomous capabilities. Some specific task applications of the FTS and partial automation approaches of these tasks will also be discussed in this paper.

The Space Station Freedom Flight Telerobotic Servicer: the design and evolution of a dexterous space robot.

PubMed

McCain, H G; Andary, J F; Hewitt, D R; Haley, D C

1991-01-01

The Flight Telerobotic Servicer (FTS) Project at the Goddard Space Flight Center is developing an advanced telerobotic system to assist in and reduce crew extravehicular activity (EVA) for Space Station) Freedom (SSF). The FTS will provide a telerobotic capability to the Freedom Station in the early assembly phases of the program and will be employed for assembly, maintenance, and inspection applications throughout the lifetime of the space station. Appropriately configured elements of the FTS will also be employed for robotic manipulation in remote satellite servicing applications and possibly the Lunar/Mars Program. In mid-1989, the FTS entered the flight system design and implementation phase (Phase C/D) of development with the signing of the FTS prime contract with Martin Marietta Astronautics Group in Denver, Colorado. The basic FTS design is now established and can be reported on in some detail. This paper will describe the FTS flight system design and the rationale for the specific design approaches and component selections. The current state of space technology and the nature of the FTS task dictate that the FTS be designed with sophisticated teleoperation capabilities for its initial primary operating mode. However, there are technologies, such as advanced computer vision and autonomous planning techniques currently in research and advanced development phases which would greatly enhance the FTS capabilities to perform autonomously in less structured work environments. Therefore, a specific requirement on the initial FTS design is that it has the capability to evolve as new technology becomes available. This paper will describe the FTS design approach for evolution to more autonomous capabilities. Some specific task applications of the FTS and partial automation approaches of these tasks will also be discussed in this paper.

The Space Station Freedom Flight Telerobotic Servicer: the design and evolution of a dexterous space robot

NASA Technical Reports Server (NTRS)

McCain, H. G.; Andary, J. F.; Hewitt, D. R.; Haley, D. C.

1991-01-01

The Flight Telerobotic Servicer (FTS) Project at the Goddard Space Flight Center is developing an advanced telerobotic system to assist in and reduce crew extravehicular activity (EVA) for Space Station) Freedom (SSF). The FTS will provide a telerobotic capability to the Freedom Station in the early assembly phases of the program and will be employed for assembly, maintenance, and inspection applications throughout the lifetime of the space station. Appropriately configured elements of the FTS will also be employed for robotic manipulation in remote satellite servicing applications and possibly the Lunar/Mars Program. In mid-1989, the FTS entered the flight system design and implementation phase (Phase C/D) of development with the signing of the FTS prime contract with Martin Marietta Astronautics Group in Denver, Colorado. The basic FTS design is now established and can be reported on in some detail. This paper will describe the FTS flight system design and the rationale for the specific design approaches and component selections. The current state of space technology and the nature of the FTS task dictate that the FTS be designed with sophisticated teleoperation capabilities for its initial primary operating mode. However, there are technologies, such as advanced computer vision and autonomous planning techniques currently in research and advanced development phases which would greatly enhance the FTS capabilities to perform autonomously in less structured work environments. Therefore, a specific requirement on the initial FTS design is that it has the capability to evolve as new technology becomes available. This paper will describe the FTS design approach for evolution to more autonomous capabilities. Some specific task applications of the FTS and partial automation approaches of these tasks will also be discussed in this paper.

The JAU-JPL anthropomorphic telerobot

NASA Technical Reports Server (NTRS)

Jau, Bruno M.

1989-01-01

Work in progress on the new anthropomorphic telerobot is described. The initial robot configuration consists of a seven DOF arm and a sixteen DOF hand, having three fingers and a thumb. The robot has active compliance, enabling subsequent dual arm manipulations. To control the rather complex configuration of this robot, an exoskeleton master arm harness and a glove controller were built. The controller will be used for teleoperational tasks and as a research tool to efficiently teach the computer controller advanced manipulation techniques.

Interactive Scene Analysis Module - A sensor-database fusion system for telerobotic environments

NASA Technical Reports Server (NTRS)

Cooper, Eric G.; Vazquez, Sixto L.; Goode, Plesent W.

1992-01-01

Accomplishing a task with telerobotics typically involves a combination of operator control/supervision and a 'script' of preprogrammed commands. These commands usually assume that the location of various objects in the task space conform to some internal representation (database) of that task space. The ability to quickly and accurately verify the task environment against the internal database would improve the robustness of these preprogrammed commands. In addition, the on-line initialization and maintenance of a task space database is difficult for operators using Cartesian coordinates alone. This paper describes the Interactive Scene' Analysis Module (ISAM) developed to provide taskspace database initialization and verification utilizing 3-D graphic overlay modelling, video imaging, and laser radar based range imaging. Through the fusion of taskspace database information and image sensor data, a verifiable taskspace model is generated providing location and orientation data for objects in a task space. This paper also describes applications of the ISAM in the Intelligent Systems Research Laboratory (ISRL) at NASA Langley Research Center, and discusses its performance relative to representation accuracy and operator interface efficiency.

Man-machine interface issues in space telerobotics: A JPL research and development program

NASA Technical Reports Server (NTRS)

Bejczy, A. K.

1987-01-01

Technology issues related to the use of robots as man-extension or telerobot systems in space are discussed and exemplified. General considerations are presentd on control and information problems in space teleoperation and on the characteristics of Earth orbital teleoperation. The JPL R and D work in the area of man-machine interface devices and techniques for sensing and computer-based control is briefly summarized. The thrust of this R and D effort is to render space teleoperation efficient and safe through the use of devices and techniques which will permit integrated and task-level (intelligent) two-way control communication between human operator and telerobot machine in Earth orbit. Specific control and information display devices and techniques are discussed and exemplified with development results obtained at JPL in recent years.

Issues, concerns, and initial implementation results for space based telerobotic control

NASA Technical Reports Server (NTRS)

Lawrence, D. A.; Chapel, J. D.; Depkovich, T. M.

1987-01-01

Telerobotic control for space based assembly and servicing tasks presents many problems in system design. Traditional force reflection teleoperation schemes are not well suited to this application, and the approaches to compliance control via computer algorithms have yet to see significant testing and comparison. These observations are discussed in detail, as well as the concerns they raise for imminent design and testing of space robotic systems. As an example of the detailed technical work yet to be done before such systems can be specified, a particular approach to providing manipulator compliance is examined experimentally and through modeling and analysis. This yields some initial insight into the limitations and design trade-offs for this class of manipulator control schemes. Implications of this investigation for space based telerobots are discussed in detail.

System engineering techniques for establishing balanced design and performance guidelines for the advanced telerobotic testbed

NASA Technical Reports Server (NTRS)

Zimmerman, W. F.; Matijevic, J. R.

1987-01-01

Novel system engineering techniques have been developed and applied to establishing structured design and performance objectives for the Telerobotics Testbed that reduce technical risk while still allowing the testbed to demonstrate an advancement in state-of-the-art robotic technologies. To estblish the appropriate tradeoff structure and balance of technology performance against technical risk, an analytical data base was developed which drew on: (1) automation/robot-technology availability projections, (2) typical or potential application mission task sets, (3) performance simulations, (4) project schedule constraints, and (5) project funding constraints. Design tradeoffs and configuration/performance iterations were conducted by comparing feasible technology/task set configurations against schedule/budget constraints as well as original program target technology objectives. The final system configuration, task set, and technology set reflected a balanced advancement in state-of-the-art robotic technologies, while meeting programmatic objectives and schedule/cost constraints.

Plan recognition and generalization in command languages with application to telerobotics

NASA Technical Reports Server (NTRS)

Yared, Wael I.; Sheridan, Thomas B.

1991-01-01

A method for pragmatic inference as a necessary accompaniment to command languages is proposed. The approach taken focuses on the modeling and recognition of the human operator's intent, which relates sequences of domain actions ('plans') to changes in some model of the task environment. The salient feature of this module is that it captures some of the physical and linguistic contextual aspects of an instruction. This provides a basis for generalization and reinterpretation of the instruction in different task environments. The theoretical development is founded on previous work in computational linguistics and some recent models in the theory of action and intention. To illustrate these ideas, an experimental command language to a telerobot is implemented. The program consists of three different components: a robot graphic simulation, the command language itself, and the domain-independent pragmatic inference module. Examples of task instruction processes are provided to demonstrate the benefits of this approach.

Task automation in a successful industrial telerobot

NASA Technical Reports Server (NTRS)

Spelt, Philip F.; Jones, Sammy L.

1994-01-01

In this paper, we discuss cooperative work by Oak Ridge National Laboratory and Remotec, Inc., to automate components of the operator's workload using Remotec's Andros telerobot, thereby providing an enhanced user interface which can be retrofit to existing fielded units as well as being incorporated into new production units. Remotec's Andros robots are presently used by numerous electric utilities to perform tasks in reactors where substantial exposure to radiation exists, as well as by the armed forces and numerous law enforcement agencies. The automation of task components, as well as the video graphics display of the robot's position in the environment, will enhance all tasks performed by these users, as well as enabling performance in terrain where the robots cannot presently perform due to lack of knowledge about, for instance, the degree of tilt of the robot. Enhanced performance of a successful industrial mobile robot leads to increased safety and efficiency of performance in hazardous environments. The addition of these capabilities will greatly enhance the utility of the robot, as well as its marketability.

Experiences with the JPL telerobot testbed: Issues and insights

NASA Technical Reports Server (NTRS)

Stone, Henry W.; Balaram, Bob; Beahan, John

1989-01-01

The Jet Propulsion Laboratory's (JPL) Telerobot Testbed is an integrated robotic testbed used to develop, implement, and evaluate the performance of advanced concepts in autonomous, tele-autonomous, and tele-operated control of robotic manipulators. Using the Telerobot Testbed, researchers demonstrated several of the capabilities and technological advances in the control and integration of robotic systems which have been under development at JPL for several years. In particular, the Telerobot Testbed was recently employed to perform a near completely automated, end-to-end, satellite grapple and repair sequence. The task of integrating existing as well as new concepts in robot control into the Telerobot Testbed has been a very difficult and timely one. Now that researchers have completed the first major milestone (i.e., the end-to-end demonstration) it is important to reflect back upon experiences and to collect the knowledge that has been gained so that improvements can be made to the existing system. It is also believed that the experiences are of value to the others in the robotics community. Therefore, the primary objective here will be to use the Telerobot Testbed as a case study to identify real problems and technological gaps which exist in the areas of robotics and in particular systems integration. Such problems have surely hindered the development of what could be reasonably called an intelligent robot. In addition to identifying such problems, researchers briefly discuss what approaches have been taken to resolve them or, in several cases, to circumvent them until better approaches can be developed.

Integration of task level planning and diagnosis for an intelligent robot

NASA Technical Reports Server (NTRS)

Chan, Amy W.

1992-01-01

A satellite floating space is diagnosed with a telerobot attached performing maintenance or replacement tasks. This research included three objectives. The first objective was to generate intelligent path planning for a robot to move around a satellite. The second objective was to diagnose possible faulty scenarios in the satellite. The third objective included two tasks. The first task was to combine intelligent path planning with diagnosis. The second task was to build an interface between the combined intelligent system with Robosim. The ability of a robot to deal with unexpected scenarios is particularly important in space since the situation could be different from time to time so that the telerobot must be capable of detecting that the situation has changed and the necessity may exist to alter its behavior based on the new situation. The feature of allowing human-in-the-loop is also very important in space. In some extreme cases, the situation is beyond the capability of a robot so our research project allows the human to override the decision of a robot.

The JPL telerobotic Manipulator Control and Mechanization (MCM) subsystem

NASA Technical Reports Server (NTRS)

Hayati, Samad; Lee, Thomas S.; Tso, Kam; Backes, Paul; Kan, Edwin; Lloyd, J.

1989-01-01

The Manipulator Control and Mechanization (MCM) subsystem of the telerobot system provides the real-time control of the robot manipulators in autonomous and teleoperated modes and real time input/output for a variety of sensors and actuators. Substantial hardware and software are included in this subsystem which interfaces in the hierarchy of the telerobot system with the other subsystems. The other subsystems are: run time control, task planning and reasoning, sensing and perception, and operator control subsystem. The architecture of the MCM subsystem, its capabilities, and details of various hardware and software elements are described. Important improvements in the MCM subsystem over the first version are: dual arm coordinated trajectory generation and control, addition of integrated teleoperation, shared control capability, replacement of the ultimate controllers with motor controllers, and substantial increase in real time processing capability.

Dual use display systems for telerobotics

NASA Technical Reports Server (NTRS)

Massimino, Michael J.; Meschler, Michael F.; Rodriguez, Alberto A.

1994-01-01

This paper describes a telerobotics display system, the Multi-mode Manipulator Display System (MMDS), that has applications for a variety of remotely controlled tasks. Designed primarily to assist astronauts with the control of space robotics systems, the MMDS has applications for ground control of space robotics as well as for toxic waste cleanup, undersea, remotely operated vehicles, and other environments which require remote operations. The MMDS has three modes: (1) Manipulator Position Display (MPD) mode, (2) Joint Angle Display (JAD) mode, and (3) Sensory Substitution (SS) mode. These three modes are discussed in the paper.

Temporal logics meet telerobotics

NASA Technical Reports Server (NTRS)

Rutten, Eric; Marce, Lionel

1989-01-01

The specificity of telerobotics being the presence of a human operator, decision assistance tools are necessary for the operator, especially in hostile environments. In order to reduce execution hazards due to a degraded ability for quick and efficient recovery of unexpected dangerous situations, it is of importance to have the opportunity, amongst others, to simulate the possible consequences of a plan before its actual execution, in order to detect these problematic situations. Hence the idea of providing the operator with a simulator enabling him to verify the temporal and logical coherence of his plans. Therefore, the power of logical formalisms is used for representation and deduction purposes. Starting from the class of situations that are represented, a STRIPS (the STanford Research Institute Problem Solver)-like formalism and its underlying logic are adapted to the simulation of plans of actions in time. The choice of a temporal logic enables to build a world representation, on which the effects of plans, grouping actions into control structures, will be transcribed by the simulation, resulting in a verdict and information about the plan's coherence.

Haptics-based immersive telerobotic system for improvised explosive device disposal: Are two hands better than one?

NASA Astrophysics Data System (ADS)

Erickson, David; Lacheray, Hervé; Lambert, Jason Michel; Mantegh, Iraj; Crymble, Derry; Daly, John; Zhao, Yan

2012-06-01

State-of-the-art robotic explosive ordnance disposal robotics have not, in general, adopted recent advances in control technology and man-machine interfaces and lag many years behind academia. This paper describes the Haptics-based Immersive Telerobotic System project investigating an immersive telepresence envrionment incorporating advanced vehicle control systems, Augmented immersive sensory feedback, dynamic 3D visual information, and haptic feedback for explosive ordnance disposal operators. The project aim is to provide operatiors a more sophisticated interface and expand sensory input to perform complex tasks to defeat improvised explosive devices successfully. The introduction of haptics and immersive teleprescence has the potential to shift the way teleprescence systems work for explosive ordnance disposal tasks or more widely for first responders scenarios involving remote unmanned ground vehicles.

Robust telerobotics - an integrated system for waste handling, characterization and sorting

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

Couture, S.A.; Hurd, R.L.; Wilhelmsen, K.C.

The Mixed Waste Management Facility (MWMF) at the Lawrence Livermore National Laboratory was designed to serve as a national testbed to demonstrate integrated technologies for the treatment of low-level organic mixed waste at a pilot-plant scale. Pilot-scale demonstration serves to bridge the gap between mature, bench-scale proven technologies and full-scale treatment facilities by providing the infrastructure needed to evaluate technologies in an integrated, front-end to back-end facility. Consistent with the intent to focus on technologies that are ready for pilot scale deployment, the front-end handling and feed preparation of incoming waste material has been designed to demonstrate the application ofmore » emerging robotic and remotely operated handling systems. The selection of telerobotics for remote handling in MWMF was made based on a number of factors - personnel protection, waste generation, maturity, cost, flexibility and extendibility. Telerobotics, or shared control of a manipulator by an operator and a computer, provides the flexibility needed to vary the amount of automation or operator intervention according to task complexity. As part of the telerobotics design effort, the technical risk of deploying the technology was reduced through focused developments and demonstrations. The work involved integrating key tools (1) to make a robust telerobotic system that operates at speeds and reliability levels acceptable to waste handling operators and, (2) to demonstrate an efficient operator interface that minimizes the amount of special training and skills needed by the operator. This paper describes the design and operation of the prototype telerobotic waste handling and sorting system that was developed for MWMF.« less

Second AIAA/NASA USAF Symposium on Automation, Robotics and Advanced Computing for the National Space Program

NASA Technical Reports Server (NTRS)

Myers, Dale

1987-01-01

An introduction is given to NASA goals in the development of automation (expert systems) and robotics technologies in the Space Station program. Artificial intelligence (AI) has been identified as a means to lowering ground support costs. Telerobotics will enhance space assembly, servicing and repair capabilities, and will be used for an estimated half of the necessary EVA tasks. The general principles guiding NASA in the design, development, ground-testing, interactions with industry and construction of the Space Station component systems are summarized. The telerobotics program has progressed to a point where a telerobot servicer is a firm component of the first Space Station element launch, to support assembly, maintenance and servicing of the Station. The University of Wisconsin has been selected for the establishment of a Center for the Commercial Development of Space, specializing in space automation and robotics.

Speech versus manual control of camera functions during a telerobotic task

NASA Technical Reports Server (NTRS)

Bierschwale, John M.; Sampaio, Carlos E.; Stuart, Mark A.; Smith, Randy L.

1989-01-01

Voice input for control of camera functions was investigated in this study. Objective were to (1) assess the feasibility of a voice-commanded camera control system, and (2) identify factors that differ between voice and manual control of camera functions. Subjects participated in a remote manipulation task that required extensive camera-aided viewing. Each subject was exposed to two conditions, voice and manual input, with a counterbalanced administration order. Voice input was found to be significantly slower than manual input for this task. However, in terms of remote manipulator performance errors and subject preference, there was no difference between modalities. Voice control of continuous camera functions is not recommended. It is believed that the use of voice input for discrete functions, such as multiplexing or camera switching, could aid performance. Hybrid mixes of voice and manual input may provide the best use of both modalities. This report contributes to a better understanding of the issues that affect the design of an efficient human/telerobot interface.

Execution environment for intelligent real-time control systems

NASA Technical Reports Server (NTRS)

Sztipanovits, Janos

1987-01-01

Modern telerobot control technology requires the integration of symbolic and non-symbolic programming techniques, different models of parallel computations, and various programming paradigms. The Multigraph Architecture, which has been developed for the implementation of intelligent real-time control systems is described. The layered architecture includes specific computational models, integrated execution environment and various high-level tools. A special feature of the architecture is the tight coupling between the symbolic and non-symbolic computations. It supports not only a data interface, but also the integration of the control structures in a parallel computing environment.

Ground operation of the mobile servicing system on Space Station Freedom

NASA Astrophysics Data System (ADS)

Wojcik, Z. A.

1992-11-01

Space Station Freedom (SSF) will be assembled in the 1995 to 2000 time period, when permanently manned capability (PMC) will be achieved. During the build phase and after PMC, the Mobile Servicing System (MSS) will be used as a tool to assist crew in the building and in assembly and all maintenance aspects of SSF. Operation of the MSS will be executed and controlled by on-orbit crew, thereby having an impact on the limited crew time and resources. The current plan specifies that the MSS will not be operable when crew are not present. Simulations have been carried out to quantify the maintenance workload expected over the life of SSF. These simulations predict a peak in maintenance demand occurring even before PMC is achieved. The MSS is key to executing those maintenance tasks, and as a result, the demands on MSS crew resource will likely exceed availability, thereby creating a backlog of maintenance actions and negatively impacting SSF effectiveness. Ground operated telerobotics (GOT), the operation of the MSS from the ground, is being proposed as an approach to reducing the anticipated maintenance backlog, along with reducing crew workload when the MSS is executing simple or repetitive tasks. GOT would be implemented in a phased approach, both in terms of the type of activity carried out and the point of control gradually passing from on-orbit crew to ground personnel. The benefits of GOT are expressed in terms of reduced on-orbit crew workload, greater availability of the MSS during the post-PMC period, and the ability to significantly reduce or even eliminate any maintenance action backlog. The benefits section compares GOT with crew operation timelines, and identifies other benefits of GOT. Critical factors such as safety, space-ground communication latency, simulation, operations planning, and design considerations are reviewed.

Generalized compliant motion primitive

NASA Technical Reports Server (NTRS)

Backes, Paul G. (Inventor)

1994-01-01

This invention relates to a general primitive for controlling a telerobot with a set of input parameters. The primitive includes a trajectory generator; a teleoperation sensor; a joint limit generator; a force setpoint generator; a dither function generator, which produces telerobot motion inputs in a common coordinate frame for simultaneous combination in sensor summers. Virtual return spring motion input is provided by a restoration spring subsystem. The novel features of this invention include use of a single general motion primitive at a remote site to permit the shared and supervisory control of the robot manipulator to perform tasks via a remotely transferred input parameter set.

Space Station flight telerobotic servicer functional requirements development

NASA Technical Reports Server (NTRS)

Oberright, John; Mccain, Harry; Whitman, Ruth I.

1987-01-01

The Space Station flight telerobotic servicer (FTS), a flight robotic system for use on the first Space Station launch, is described. The objectives of the FTS program include: (1) the provision of an alternative crew EVA by supporting the crew in assembly, maintenance, and servicing activities, and (2) the improvement of crew safety by performing hazardous tasks such as spacecraft refueling or thermal and power system maintenance. The NASA/NBS Standard Reference Model provides the generic, hierarchical, structured functional control definition for the system. It is capable of accommodating additional degrees of machine intelligence in the future.

Redundant arm control in a supervisory and shared control system

NASA Technical Reports Server (NTRS)

Backes, Paul G.; Long, Mark K.

1992-01-01

The Extended Task Space Control approach to robotic operations based on manipulator behaviors derived from task requirements is described. No differentiation between redundant and non-redundant robots is made at the task level. The manipulation task behaviors are combined into a single set of motion commands. The manipulator kinematics are used subsequently in mapping motion commands into actuator commands. Extended Task Space Control is applied to a Robotics Research K-1207 seven degree-of-freedom manipulator in a supervisory telerobot system as an example.

Software architecture for a distributed real-time system in Ada, with application to telerobotics

NASA Technical Reports Server (NTRS)

Olsen, Douglas R.; Messiora, Steve; Leake, Stephen

1992-01-01

The architecture structure and software design methodology presented is described in the context of telerobotic application in Ada, specifically the Engineering Test Bed (ETB), which was developed to support the Flight Telerobotic Servicer (FTS) Program at GSFC. However, the nature of the architecture is such that it has applications to any multiprocessor distributed real-time system. The ETB architecture, which is a derivation of the NASA/NBS Standard Reference Model (NASREM), defines a hierarchy for representing a telerobot system. Within this hierarchy, a module is a logical entity consisting of the software associated with a set of related hardware components in the robot system. A module is comprised of submodules, which are cyclically executing processes that each perform a specific set of functions. The submodules in a module can run on separate processors. The submodules in the system communicate via command/status (C/S) interface channels, which are used to send commands down and relay status back up the system hierarchy. Submodules also communicate via setpoint data links, which are used to transfer control data from one submodule to another. A submodule invokes submodule algorithms (SMA's) to perform algorithmic operations. Data that describe or models a physical component of the system are stored as objects in the World Model (WM). The WM is a system-wide distributed database that is accessible to submodules in all modules of the system for creating, reading, and writing objects.

Telepresence and telerobotics

NASA Technical Reports Server (NTRS)

Garin, John; Matteo, Joseph; Jennings, Von Ayre

1988-01-01

The capability for a single operator to simultaneously control complex remote multi degree of freedom robotic arms and associated dextrous end effectors is being developed. An optimal solution within the realm of current technology, can be achieved by recognizing that: (1) machines/computer systems are more effective than humans when the task is routine and specified, and (2) humans process complex data sets and deal with the unpredictable better than machines. These observations lead naturally to a philosophy in which the human's role becomes a higher level function associated with planning, teaching, initiating, monitoring, and intervening when the machine gets into trouble, while the machine performs the codifiable tasks with deliberate efficiency. This concept forms the basis for the integration of man and telerobotics, i.e., robotics with the operator in the control loop. The concept of integration of the human in the loop and maximizing the feed-forward and feed-back data flow is referred to as telepresence.

The sensing and perception subsystem of the NASA research telerobot

NASA Technical Reports Server (NTRS)

Wilcox, B.; Gennery, D. B.; Bon, B.; Litwin, T.

1987-01-01

A useful space telerobot for on-orbit assembly, maintenance, and repair tasks must have a sensing and perception subsystem which can provide the locations, orientations, and velocities of all relevant objects in the work environment. This function must be accomplished with sufficient speed and accuracy to permit effective grappling and manipulation. Appropriate symbolic names must be attached to each object for use by higher-level planning algorithms. Sensor data and inferences must be presented to the remote human operator in a way that is both comprehensible in ensuring safe autonomous operation and useful for direct teleoperation. Research at JPL toward these objectives is described.

Geometric reasoning

NASA Technical Reports Server (NTRS)

Woodbury, R. F.; Oppenheim, I. J.

1987-01-01

Cognitive robot systems are ones in which sensing and representation occur, from which task plans and tactics are determined. Such a robot system accomplishes a task after being told what to do, but determines for itself how to do it. Cognition is required when the work environment is uncontrolled, when contingencies are prevalent, or when task complexity is large; it is useful in any robotic mission. A number of distinguishing features can be associated with cognitive robotics, and one emphasized here is the role of artificial intelligence in knowledge representation and in planning. While space telerobotics may elude some of the problems driving cognitive robotics, it shares many of the same demands, and it can be assumed that capabilities developed for cognitive robotics can be employed advantageously for telerobotics in general. The top level problem is task planning, and it is appropriate to introduce a hierarchical view of control. Presented with certain mission objectives, the system must generate plans (typically) at the strategic, tactical, and reflexive levels. The structure by which knowledge is used to construct and update these plans endows the system with its cognitive attributes, and with the ability to deal with contingencies, changes, unknowns, and so on. Issues of representation and reasoning which are absolutely fundamental to robot manipulation, decisions based upon geometry, are discussed here, not AI task planning per se.

Laboratory testing of candidate robotic applications for space

NASA Technical Reports Server (NTRS)

Purves, R. B.

1987-01-01

Robots have potential for increasing the value of man's presence in space. Some categories with potential benefit are: (1) performing extravehicular tasks like satellite and station servicing, (2) supporting the science mission of the station by manipulating experiment tasks, and (3) performing intravehicular activities which would be boring, tedious, exacting, or otherwise unpleasant for astronauts. An important issue in space robotics is selection of an appropriate level of autonomy. In broad terms three levels of autonomy can be defined: (1) teleoperated - an operator explicitly controls robot movement; (2) telerobotic - an operator controls the robot directly, but by high-level commands, without, for example, detailed control of trajectories; and (3) autonomous - an operator supplies a single high-level command, the robot does all necessary task sequencing and planning to satisfy the command. Researchers chose three projects for their exploration of technology and implementation issues in space robots, one each of the three application areas, each with a different level of autonomy. The projects were: (1) satellite servicing - teleoperated; (2) laboratory assistant - telerobotic; and (3) on-orbit inventory manager - autonomous. These projects are described and some results of testing are summarized.

Design guidelines for remotely maintainable equipment

NASA Technical Reports Server (NTRS)

Clarke, Margaret M.; Manouchehri, Davoud

1988-01-01

The quantity and complexity of on-orbit assets will increase significantly over the next decade. Maintaining and servicing these costly assets represent a difficult challenge. Three general methods are proposed to maintain equipment while it is still in orbit: an extravehicular activity (EVA) crew can perform the task in an unpressurized maintenance area outside any space vehicle; an intravehicular activity (IVA) crew can perform the maintenance in a shirt sleeve environment, perhaps at a special maintenance work station in a space vehicle; or a telerobotic manipulator can perform the maintenance in an unpressurized maintenance area at a distance from the crew (who may be EVA, IVA, or on the ground). However, crew EVA may not always be possible; the crew may have other demands on their time that take precedence. In addition, the orbit of the tasks themselves may be impossible for crew entry. Also crew IVA may not always be possible as option for equipment maintenance. For example, the equipment may be too large to fit through the vehicle airlock. Therefore, in some circumstances, the third option, telerobotic manipulation, may be the only feasible option. Telerobotic manipulation has, therefore, an important role for on-orbit maintenance. It is not only used for the reasons outlined above, but also used in some cases as backup to the EVA crew in an orbit that they can reach.

Speech versus manual control of camera functions during a telerobotic task

NASA Technical Reports Server (NTRS)

Bierschwale, John M.; Sampaio, Carlos E.; Stuart, Mark A.; Smith, Randy L.

1993-01-01

This investigation has evaluated the voice-commanded camera control concept. For this particular task, total voice control of continuous and discrete camera functions was significantly slower than manual control. There was no significant difference between voice and manual input for several types of errors. There was not a clear trend in subjective preference of camera command input modality. Task performance, in terms of both accuracy and speed, was very similar across both levels of experience.

Stereoscopic, Force-Feedback Trainer For Telerobot Operators

NASA Technical Reports Server (NTRS)

Kim, Won S.; Schenker, Paul S.; Bejczy, Antal K.

1994-01-01

Computer-controlled simulator for training technicians to operate remote robots provides both visual and kinesthetic virtual reality. Used during initial stage of training; saves time and expense, increases operational safety, and prevents damage to robots by inexperienced operators. Computes virtual contact forces and torques of compliant robot in real time, providing operator with feel of forces experienced by manipulator as well as view in any of three modes: single view, two split views, or stereoscopic view. From keyboard, user specifies force-reflection gain and stiffness of manipulator hand for three translational and three rotational axes. System offers two simulated telerobotic tasks: insertion of peg in hole in three dimensions, and removal and insertion of drawer.

Space Station Freedom coupling tasks: An evaluation of their telerobotic and EVA compatibility

NASA Technical Reports Server (NTRS)

Sampaio, Carlos E.; Bierschwale, John M.; Fleming, Terence F.; Stuart, Mark A.

1993-01-01

Of the couplings included in this study, several design components were found to be of interest. With respect to the operation of the couplings, the various concepts resulted in differing reactions from the four subjects who participated in this study. The purpose of this study was not to conceive the final coupling design. Rather, it was intended as a step along an interactive process. The newly modified coupling will be included in a series of further controlled, as well as subjective, evaluations. This part of the ongoing work in the Remote Operator Interaction Laboratory (ROIL) designed to enhance the overall interface by improving design at both the teleoperator and telerobot ends of the system.

Virtual Reality Calibration for Telerobotic Servicing

NASA Technical Reports Server (NTRS)

Kim, W.

1994-01-01

A virtual reality calibration technique of matching a virtual environment of simulated graphics models in 3-D geometry and perspective with actual camera views of the remote site task environment has been developed to enable high-fidelity preview/predictive displays with calibrated graphics overlay on live video.

Use of control umbilicals as a deployment mode for free flying telerobotic work systems

NASA Technical Reports Server (NTRS)

Kuehn, J. S.; Selle, E. D.

1987-01-01

Work to date on telerobotic work systems for use in space generally consider two deployment modes, free flying, or fixed within a limited work envelope. Control tethers may be employed to obtain a number of operational advantages and added flexibility in the basing and deployment of telerobotic work systems. Use of a tether allows the work system to be separated into two major modules, the remote work package and the control module. The Remote Work Package (RWP) comprises the free flying portion of the work system while the Control Module (CM) remains at the work system base. The chief advantage of this configuration is that only the components required for completion of the work task must be located at the work site. Reaction mass used in free flight is stored at the Control module and supplied to the RWP through the tether, eliminating the need for the RWP to carry it. The RWP can be made less massive than a self contained free flying work system. As a result, reaction mass required for free flight is lower than for a self contained free flyer.

Location of planar targets in three space from monocular images

NASA Technical Reports Server (NTRS)

Cornils, Karin; Goode, Plesent W.

1987-01-01

Many pieces of existing and proposed space hardware that would be targets of interest for a telerobot can be represented as planar or near-planar surfaces. Examples include the biostack modules on the Long Duration Exposure Facility, the panels on Solar Max, large diameter struts, and refueling receptacles. Robust and temporally efficient methods for locating such objects with sufficient accuracy are therefore worth developing. Two techniques that derive the orientation and location of an object from its monocular image are discussed and the results of experiments performed to determine translational and rotational accuracy are presented. Both the quadrangle projection and elastic matching techniques extract three-space information using a minimum of four identifiable target points and the principles of the perspective transformation. The selected points must describe a convex polygon whose geometric characteristics are prespecified in a data base. The rotational and translational accuracy of both techniques was tested at various ranges. This experiment is representative of the sensing requirements involved in a typical telerobot target acquisition task. Both techniques determined target location to an accuracy sufficient for consistent and efficient acquisition by the telerobot.

Open control/display system for a telerobotics work station

NASA Technical Reports Server (NTRS)

Keslowitz, Saul

1987-01-01

A working Advanced Space Cockpit was developed that integrated advanced control and display devices into a state-of-the-art multimicroprocessor hardware configuration, using window graphics and running under an object-oriented, multitasking real-time operating system environment. This Open Control/Display System supports the idea that the operator should be able to interactively monitor, select, control, and display information about many payloads aboard the Space Station using sets of I/O devices with a single, software-reconfigurable workstation. This is done while maintaining system consistency, yet the system is completely open to accept new additions and advances in hardware and software. The Advanced Space Cockpit, linked to Grumman's Hybrid Computing Facility and Large Amplitude Space Simulator (LASS), was used to test the Open Control/Display System via full-scale simulation of the following tasks: telerobotic truss assembly, RCS and thermal bus servicing, CMG changeout, RMS constrained motion and space constructible radiator assembly, HPA coordinated control, and OMV docking and tumbling satellite retrieval. The proposed man-machine interface standard discussed has evolved through many iterations of the tasks, and is based on feedback from NASA and Air Force personnel who performed those tasks in the LASS.

Hand controller commonality evaluation process

NASA Technical Reports Server (NTRS)

Stuart, Mark A.; Bierschwale, John M.; Wilmington, Robert P.; Adam, Susan C.; Diaz, Manuel F.; Jensen, Dean G.

1993-01-01

Hand controller selection for NASA's Orbiter and Space Station Freedom is an important area of human-telerobot interface design and evaluation. These input devices will control remotely operated systems that include large crane-like manipulators (e.g., Remote Manipulator System or RMS), smaller, more dexterous manipulators (e.g., Flight Telerobotic Servicer or FTS), and free flyers (e.g., Orbital Maneuvering Vehicle or OMV). Candidate hand controller configurations for these systems vary in many ways: shape, size, number of degrees-of-freedom (DOF), operating modes, provision of force reflection, range of movement, and 'naturalness' of use. Unresolved design implementation issues remain, including such topics as how the current Orbiter RMS rotational and translational rate hand controllers compare with the proposed Space Station Freedom hand controllers, the advantages that position hand controllers offer for these applications, and whether separate hand controller configurations are required for each application. Since previous studies contain little empirical hand controller task performance data, a controlled study is needed that tests Space Station Freedom candidate hand controllers during representative tasks. This study also needs to include anthropometric and biomechanical considerations.

Telerobotics - Display, control, and communication problems

NASA Technical Reports Server (NTRS)

Stark, Lawrence; Kim, Won-Soo; Tendick, Frank; Hannaford, Blake; Ellis, Stephen

1987-01-01

An experimental telerobotics simulation is described suitable for studying human operator (HO) performance. Simple manipulator pick-and-place and tracking tasks allowed quantitative comparison of a number of calligraphic display viewing conditions. An enhanced perspective display was effective with a reference line from target to base, with or without a complex three-dimensional grid framing the view. This was true especially if geometrical display parameters such as azimuth and elevation were arranged to be near optimal. Quantitative comparisons were made possible, utilizing control performance measures such as root mean square error. There was a distinct preference for controlling the manipulator in end-effector Cartesian space for the primitive pick-and-place task, rather than controlling joint angles and then, via direct kinematis, the end-effector position. An introduced communication delay was found to produce decrease in performance. In considerable part, this difficulty could be compensated for by preview control information. The fact that neurological control of normal human movement contains a sampled data period of 0.2 s may relate to this robustness of HO control to delay.

Dexterous Orbital Servicing System (DOSS)

NASA Technical Reports Server (NTRS)

Price, Charles R.; Berka, Reginald B.; Chladek, John T.

1994-01-01

The Dexterous Orbiter Servicing System (DOSS) is a dexterous robotic spaceflight system that is based on the manipulator designed as part of the Flight Telerobotics Servicer program for the Space Station Freedom and built during a 'technology capture' effort that was commissioned when the FTS was cancelled from the Space Station Freedom program. The FTS technology capture effort yielded one flight manipulator and the 1 g hydraulic simulator that had been designed as an integrated test tool and crew trainer. The DOSS concept was developed to satisfy needs of the telerobotics research community, the space shuttle, and the space station. As a flight testbed, DOSS would serve as a baseline reference for testing the performance of advanced telerobotics and intelligent robotics components. For shuttle, the DOSS, configured as a movable dexterous tool, would be used to provide operational flexibility for payload operations and contingency operations. As a risk mitigation flight demonstration, the DOSS would serve the International Space Station to characterize the end to end system performance of the Special Purpose Dexterous Manipulator performing assembly and maintenance tasks with actual ISSA orbital replacement units. Currently, the most likely entrance of the DOSS into spaceflight is a risk mitigation flight experiment for the International Space Station.

Telerobotics for depot modernization

NASA Technical Reports Server (NTRS)

Leahy, M. B., Jr.; Petroski, S. B.

1994-01-01

Development and application of telerobotics technology for the enhancement of the quality of the Air Logistic Centers (ALC) repair and remanufacturing processes is described. Telerobotics provides the means for bridging the gap between manual operation and full automation. The Robotics and Automation Center for Excellence (RACE) initiated the Unified Telerobotics Architecture Project (UTAP) to support the development and application of telerobotics for depot operation.

Initial Experience Using a Telerobotic Ultrasound System for Adult Abdominal Sonography.

PubMed

Adams, Scott J; Burbridge, Brent E; Badea, Andreea; Langford, Leanne; Vergara, Vincent; Bryce, Rhonda; Bustamante, Luis; Mendez, Ivar M; Babyn, Paul S

2017-08-01

The study sought to assess the feasibility of performing adult abdominal examinations using a telerobotic ultrasound system in which radiologists or sonographers can control fine movements of a transducer and all ultrasound settings from a remote location. Eighteen patients prospectively underwent a conventional sonography examination (using EPIQ 5 [Philips] or LOGIQ E9 [GE Healthcare]) followed by a telerobotic sonography examination (using the MELODY System [AdEchoTech] and SonixTablet [BK Ultrasound]) according to a standardized abdominal imaging protocol. For telerobotic examinations, patients were scanned remotely by a sonographer 2.75 km away. Conventional examinations were read independently from telerobotic examinations. Image quality and acceptability to patients and sonographers was assessed. Ninety-two percent of organs visualized on conventional examinations were sufficiently visualized on telerobotic examinations. Five pathological findings were identified on both telerobotic and conventional examinations, 3 findings were identified using only conventional sonography, and 2 findings were identified using only telerobotic sonography. A paired sample t test showed no significant difference between the 2 modalities in measurements of the liver, spleen, and diameter of the proximal aorta; however, telerobotic assessments overestimated distal aorta and common bile duct diameters and underestimated kidney lengths (P values < .05). All patients responded that they would be willing to have another telerobotic examination. A telerobotic ultrasound system is feasible for performing abdominal ultrasound examinations at a distant location with minimal training and setup requirements and a moderate learning curve. Telerobotic sonography (robotic telesonography) may open up the possibility of remote ultrasound clinics for communities that lack skilled sonographers and radiologists, thereby improving access to care. Copyright © 2016 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

Kinematics of the six-degree-of-freedom force-reflecting Kraft Master

NASA Technical Reports Server (NTRS)

Williams, Robert L., II

1991-01-01

Presented here are kinematic equations for a six degree of freedom force-reflecting hand controller. The forward kinematics solution is developed and shown in simplified form. The Jacobian matrix, which uses terms from the forward kinematics solution, is derived. Both of these kinematic solutions require joint angle inputs. A calibration method is presented to determine the hand controller joint angles given the respective potentiometer readings. The kinematic relationship describing the mechanical coupling between the hand and controller shoulder and elbow joints is given. These kinematic equations may be used in an algorithm to control the hand controller as a telerobotic system component. The purpose of the hand controller is two-fold: operator commands to the telerobotic system are entered using the hand controller, and contact forces and moments from the task are reflected to the operator via the hand controller.

A distributed telerobotics construction set

NASA Technical Reports Server (NTRS)

Wise, James D.

1994-01-01

During the course of our research on distributed telerobotic systems, we have assembled a collection of generic, reusable software modules and an infrastructure for connecting them to form a variety of telerobotic configurations. This paper describes the structure of this 'Telerobotics Construction Set' and lists some of the components which comprise it.

The procedure safety system

NASA Technical Reports Server (NTRS)

Obrien, Maureen E.

1990-01-01

Telerobotic operations, whether under autonomous or teleoperated control, require a much more sophisticated safety system than that needed for most industrial applications. Industrial robots generally perform very repetitive tasks in a controlled, static environment. The safety system in that case can be as simple as shutting down the robot if a human enters the work area, or even simply building a cage around the work space. Telerobotic operations, however, will take place in a dynamic, sometimes unpredictable environment, and will involve complicated and perhaps unrehearsed manipulations. This creates a much greater potential for damage to the robot or objects in its vicinity. The Procedural Safety System (PSS) collects data from external sensors and the robot, then processes it through an expert system shell to determine whether an unsafe condition or potential unsafe condition exists. Unsafe conditions could include exceeding velocity, acceleration, torque, or joint limits, imminent collision, exceeding temperature limits, and robot or sensor component failure. If a threat to safety exists, the operator is warned. If the threat is serious enough, the robot is halted. The PSS, therefore, uses expert system technology to enhance safety thus reducing operator work load, allowing him/her to focus on performing the task at hand without the distraction of worrying about violating safety criteria.

Human-telerobot interactions - Information, control, and mental models

NASA Technical Reports Server (NTRS)

Smith, Randy L.; Gillan, Douglas J.

1987-01-01

A part of the NASA's Space Station will be a teleoperated robot (telerobot) with arms for grasping and manipulation, feet for holding onto objects, and television cameras for visual feedback. The objective of the work described in this paper is to develop the requirements and specifications for the user-telerobot interface and to determine through research and testing that the interface results in efficient system operation. The focus of the development of the user-telerobot interface is on the information required by the user, the user inputs, and the design of the control workstation. Closely related to both the information required by the user and the user's control of the telerobot is the user's mental model of the relationship between the control inputs and the telerobot's actions.

Adjustable impedance, force feedback and command language aids for telerobotics (parts 1-4 of an 8-part MIT progress report)

NASA Technical Reports Server (NTRS)

Sheridan, Thomas B.; Raju, G. Jagganath; Buzan, Forrest T.; Yared, Wael; Park, Jong

1989-01-01

Projects recently completed or in progress at MIT Man-Machine Systems Laboratory are summarized. (1) A 2-part impedance network model of a single degree of freedom remote manipulation system is presented in which a human operator at the master port interacts with a task object at the slave port in a remote location is presented. (2) The extension of the predictor concept to include force feedback and dynamic modeling of the manipulator and the environment is addressed. (3) A system was constructed to infer intent from the operator's commands and the teleoperation context, and generalize this information to interpret future commands. (4) A command language system is being designed that is robust, easy to learn, and has more natural man-machine communication. A general telerobot problem selected as an important command language context is finding a collision-free path for a robot.

The effects of spatially displaced visual feedback on remote manipulator performance

NASA Technical Reports Server (NTRS)

Smith, Randy L.; Stuart, Mark A.

1993-01-01

The results of this evaluation have important implications for the arrangement of remote manipulation worksites and the design of workstations for telerobot operations. This study clearly illustrates the deleterious effects that can accompany the performance of remote manipulator tasks when viewing conditions are less than optimal. Future evaluations should emphasize telerobot camera locations and the use of image/graphical enhancement techniques in an attempt to lessen the adverse effects of displaced visual feedback. An important finding in this evaluation is the extent to which results from previously performed direct manipulation studies can be generalized to remote manipulation studies. Even though the results obtained were very similar to those of the direct manipulation evaluations, there were differences as well. This evaluation has demonstrated that generalizations to remote manipulation applications based upon the results of direct manipulation studies are quite useful, but they should be made cautiously.

NASA/NBS (National Aeronautics and Space Administration/National Bureau of Standards) standard reference model for telerobot control system architecture (NASREM)

NASA Technical Reports Server (NTRS)

Albus, James S.; Mccain, Harry G.; Lumia, Ronald

1989-01-01

The document describes the NASA Standard Reference Model (NASREM) Architecture for the Space Station Telerobot Control System. It defines the functional requirements and high level specifications of the control system for the NASA space Station document for the functional specification, and a guideline for the development of the control system architecture, of the 10C Flight Telerobot Servicer. The NASREM telerobot control system architecture defines a set of standard modules and interfaces which facilitates software design, development, validation, and test, and make possible the integration of telerobotics software from a wide variety of sources. Standard interfaces also provide the software hooks necessary to incrementally upgrade future Flight Telerobot Systems as new capabilities develop in computer science, robotics, and autonomous system control.

Proceedings of the NASA Conference on Space Telerobotics, volume 5

NASA Technical Reports Server (NTRS)

Rodriguez, Guillermo (Editor); Seraji, Homayoun (Editor)

1989-01-01

Papers presented at the NASA Conference on Space Telerobotics are compiled. The theme of the conference was man-machine collaboration in space. The conference provided a forum for researchers and engineers to exchange ideas on the research and development required for the application of telerobotics technology to the space systems planned for the 1990's and beyond. Volume 5 contains papers related to the following subject areas: robot arm modeling and control, special topics in telerobotics, telerobotic space operations, manipulator control, flight experiment concepts, manipulator coordination, issues in artificial intelligence systems, and research activities at the Johnson Space Center.

Telerobot operator control station requirements

NASA Technical Reports Server (NTRS)

Kan, Edwin P.

1988-01-01

The operator control station of a telerobot system has unique functional and human factors requirements. It has to satisfy the needs of a truly interactive and user-friendly complex system, a telerobot system being a hybrid between a teleoperated and an autonomous system. These functional, hardware and software requirements are discussed, with explicit reference to the design objectives and constraints of the JPL/NASA Telerobot Demonstrator System.

Design Considerations for Remotely Operated Welding in Space: Task Definition and Visual Weld Monitoring Experiment

DTIC Science & Technology

1993-05-01

processes [48] ................ 91 Figure 4.14 Energy effectiveness comparison between EBW, GMAW , and PAW [48...1 10 Figure 5.2 The spectrum of control modes [76] ................. 112 Figure 5.3 Levels of control for GMAW [26...vehicular activity FTS Flight Telerobotic Servicer GMAW Gas metal arc welding GTAW Gas tungsten arc welding LEO Low-earth orbit NDT Non-destructive test

Implementation of RCCL, a robot control C library on a microVAX II

NASA Technical Reports Server (NTRS)

Lee, Jin S.; Hayati, Samad; Hayward, Vincent; Lloyd, John E.

1987-01-01

The robot control C library (RCCL), a high-level robot programing system which enables a progammer to employ a set of system calls to specify robot manipulator tasks, is discussed. The general structure of RCCL is described, and the implementation of RCCL on a microVAX II is examined. Proposed extensions and improvements of RCCL relevant to NASA's telerobotic system are addressed.

Telerobotics in rehabilitation: Barriers to a virtual existence

NASA Technical Reports Server (NTRS)

Leifer, Larry; Vanderloos, Machiel; Michalowski, Stefan

1991-01-01

The topics covered include the following: the need for telerobotics in rehabilitation; barriers to telerobotics technology in rehabilitation and health care; institutional barriers; technical barriers; and a partial view of the future.

State of the art in nuclear telerobotics: focus on the man/machine connection

NASA Astrophysics Data System (ADS)

Greaves, Amna E.

1995-12-01

The interface between the human controller and remotely operated device is a crux of telerobotic investigation today. This human-to-machine connection is the means by which we communicate our commands to the device, as well as the medium for decision-critical feedback to the operator. The amount of information transferred through the user interface is growing. This can be seen as a direct result of our need to support added complexities, as well as a rapidly expanding domain of applications. A user interface, or UI, is therefore subject to increasing demands to present information in a meaningful manner to the user. Virtual reality, and multi degree-of-freedom input devices lend us the ability to augment the man/machine interface, and handle burgeoning amounts of data in a more intuitive and anthropomorphically correct manner. Along with the aid of 3-D input and output devices, there are several visual tools that can be employed as part of a graphical UI that enhance and accelerate our comprehension of the data being presented. Thus an advanced UI that features these improvements would reduce the amount of fatigue on the teleoperator, increase his level of safety, facilitate learning, augment his control, and potentially reduce task time. This paper investigates the cutting edge concepts and enhancements that lead to the next generation of telerobotic interface systems.

Mechatronic design of haptic forceps for robotic surgery.

PubMed

Rizun, P; Gunn, D; Cox, B; Sutherland, G

2006-12-01

Haptic feedback increases operator performance and comfort during telerobotic manipulation. Feedback of grasping pressure is critical in many microsurgical tasks, yet no haptic interface for surgical tools is commercially available. Literature on the psychophysics of touch was reviewed to define the spectrum of human touch perception and the fidelity requirements of an ideal haptic interface. Mechanical design and control literature was reviewed to translate the psychophysical requirements to engineering specification. High-fidelity haptic forceps were then developed through an iterative process between engineering and surgery. The forceps are a modular device that integrate with a haptic hand controller to add force feedback for tool actuation in telerobotic or virtual surgery. Their overall length is 153 mm and their mass is 125 g. A contact-free voice coil actuator generates force feedback at frequencies up to 800 Hz. Maximum force output is 6 N (2N continuous) and the force resolution is 4 mN. The forceps employ a contact-free magnetic position sensor as well as micro-machined accelerometers to measure opening/closing acceleration. Position resolution is 0.6 microm with 1.3 microm RMS noise. The forceps can simulate stiffness greater than 20N/mm or impedances smaller than 15 g with no noticeable haptic artifacts or friction. As telerobotic surgery evolves, haptics will play an increasingly important role. Copyright 2006 John Wiley & Sons, Ltd.

Connectionist model-based stereo vision for telerobotics

NASA Technical Reports Server (NTRS)

Hoff, William; Mathis, Donald

1989-01-01

Autonomous stereo vision for range measurement could greatly enhance the performance of telerobotic systems. Stereo vision could be a key component for autonomous object recognition and localization, thus enabling the system to perform low-level tasks, and allowing a human operator to perform a supervisory role. The central difficulty in stereo vision is the ambiguity in matching corresponding points in the left and right images. However, if one has a priori knowledge of the characteristics of the objects in the scene, as is often the case in telerobotics, a model-based approach can be taken. Researchers describe how matching ambiguities can be resolved by ensuring that the resulting three-dimensional points are consistent with surface models of the expected objects. A four-layer neural network hierarchy is used in which surface models of increasing complexity are represented in successive layers. These models are represented using a connectionist scheme called parameter networks, in which a parametrized object (for example, a planar patch p=f(h,m sub x, m sub y) is represented by a collection of processing units, each of which corresponds to a distinct combination of parameter values. The activity level of each unit in the parameter network can be thought of as representing the confidence with which the hypothesis represented by that unit is believed. Weights in the network are set so as to implement gradient descent in an energy function.

Telerobotic workstation design aid

NASA Technical Reports Server (NTRS)

Corker, K.; Hudlicka, E.; Young, D.; Cramer, N.

1989-01-01

Telerobot systems are being developed to support a number of space mission applications. In low earth orbit, telerobots and teleoperated manipulators will be used in shuttle operations and space station construction/maintenance. Free flying telerobotic service vehicles will be used at low and geosynchronous orbital operations. Rovers and autonomous vehicles will be equipped with telerobotic devices in planetary exploration. In all of these systems, human operators will interact with the robot system at varied levels during the scheduled operations. The human operators may be in either orbital or ground-based control systems. To assure integrated system development and maximum utility across these systems, designers must be sensitive to the constraints and capabilities that the human brings to system operation and must be assisted in applying these human factors to system development. The simulation and analysis system is intended to serve the needs of system analysis/designers as an integrated workstation in support of telerobotic design.

A Space Data System Standard for Telerobotic Operations

NASA Technical Reports Server (NTRS)

Mittman, David S.; Martinez, Lindolfo

2014-01-01

The Telerobotics Working Group of the Mission Operations and Information Management Services Area of the Consultative Committee for Space Data Systems is drafting a document that will help bound the scope of an eventual international standard for telerobotic operations services. This paper will present the work in progress and provide background for how the international community is beginning to define standards in telerobotic operations that will help ensure the success of complex missions to explore beyond Earth orbit.

Studies in knowledge-based diagnosis of failures in robotic assembly

NASA Technical Reports Server (NTRS)

Lam, Raymond K.; Pollard, Nancy S.; Desai, Rajiv S.

1990-01-01

The telerobot diagnostic system (TDS) is a knowledge-based system that is being developed for identification and diagnosis of failures in the space robotic domain. The system is able to isolate the symptoms of the failure, generate failure hypotheses based on these symptoms, and test their validity at various levels by interpreting or simulating the effects of the hypotheses on results of plan execution. The implementation of the TDS is outlined. The classification of failures and the types of system models used by the TDS are discussed. A detailed example of the TDS approach to failure diagnosis is provided.

Force-reflection and shared compliant control in operating telemanipulators with time delay

NASA Technical Reports Server (NTRS)

Kim, Won S.; Hannaford, Blake; Bejczy, Antal K.

1992-01-01

The performance of an advanced telemanipulation system in the presence of a wide range of time delays between a master control station and a slave robot is quantified. The contemplated applications include multiple satellite links to LEO, geosynchronous operation, spacecraft local area networks, and general-purpose computer-based short-distance designs. The results of high-precision peg-in-hole tasks performed by six test operators indicate that task performance decreased linearly with introduced time delays for both kinesthetic force feedback (KFF) and shared compliant control (SCC). The rate of this decrease was substantially improved with SCC compared to KFF. Task performance at delays above 1 s was not possible using KFF. SCC enabled task performance for such delays, which are realistic values for ground-controlled remote manipulation of telerobots in space.

Human factors requirements for telerobotic command and control: The European Space Agency experimental programme

NASA Technical Reports Server (NTRS)

Stone, Robert J.

1991-01-01

Space Telerobotics research, performed under contract to the European Space Agency (ESA), concerning the execution of human factors experiments, and ultimately leading to the development of a telerobotics test bed, has been carried out since 1985 by a British Consortium consisting of British Aerospace, the United Kingdom Atomic Energy Authority and, more recently, the UK National Advanced Robotics Research Centre. The principal aim of the first study of the series was to derive preliminary requirements for a teleoperation servicing system, with reference to two mission model scenarios. The first scenario introduced the problem of communications time delays, and their likely effect on the ground-based operator in control of a manipulator system on board an unmanned servicing vehicle in Low Earth Orbit. In the second scenario, the operator was located on the NASA Orbiter aft flight deck, supervising the control of a prototype manipulator in the 'servicing' of an experimental payload in the cargo bay area. Human factors analyses centered on defining the requirements for the teleoperator workstation, such as identifying basic ergonomic requirements for workstation and panel layouts, defining teleoperation strategies, developing alphanumeric and graphic screen formats for the supervision or direct control of the manipulator, and the potential applications of expert system technology. The second study for ESA involved an experimental appraisal of some of the important issues highlighted in the first study, for which relevant human factors data did not exist. Of central importance during the second study was the issue of communications time delays and their effect on the manual control of a teleoperated manipulator from a ground-based command and control station.

The use of graphics in the design of the human-telerobot interface

NASA Technical Reports Server (NTRS)

Stuart, Mark A.; Smith, Randy L.

1989-01-01

The Man-Systems Telerobotics Laboratory (MSTL) of NASA's Johnson Space Center employs computer graphics tools in their design and evaluation of the Flight Telerobotic Servicer (FTS) human/telerobot interface on the Shuttle and on the Space Station. It has been determined by the MSTL that the use of computer graphics can promote more expedient and less costly design endeavors. Several specific examples of computer graphics applied to the FTS user interface by the MSTL are described.

Grid Task Execution

NASA Technical Reports Server (NTRS)

Hu, Chaumin

2007-01-01

IPG Execution Service is a framework that reliably executes complex jobs on a computational grid, and is part of the IPG service architecture designed to support location-independent computing. The new grid service enables users to describe the platform on which they need a job to run, which allows the service to locate the desired platform, configure it for the required application, and execute the job. After a job is submitted, users can monitor it through periodic notifications, or through queries. Each job consists of a set of tasks that performs actions such as executing applications and managing data. Each task is executed based on a starting condition that is an expression of the states of other tasks. This formulation allows tasks to be executed in parallel, and also allows a user to specify tasks to execute when other tasks succeed, fail, or are canceled. The two core components of the Execution Service are the Task Database, which stores tasks that have been submitted for execution, and the Task Manager, which executes tasks in the proper order, based on the user-specified starting conditions, and avoids overloading local and remote resources while executing tasks.

Challenges of Human-Robot Communication in Telerobotics

NASA Technical Reports Server (NTRS)

Bejczy, Antal K.

1996-01-01

Some general considerations are presented on bilateral human-telerobot control and information communication issues. Advances are reviewed related to the more conventional human-telerobot communication techniques, and some unconventional but promising communication methods are briefly discussed. Future needs and emerging application domains are briefly indicated.

Simulation of the human-telerobot interface

NASA Technical Reports Server (NTRS)

Stuart, Mark A.; Smith, Randy L.

1988-01-01

A part of NASA's Space Station will be a Flight Telerobotic Servicer (FTS) used to help assemble, service, and maintain the Space Station. Since the human operator will be required to control the FTS, the design of the human-telerobot interface must be optimized from a human factors perspective. Simulation has been used as an aid in the development of complex systems. Simulation has been especially useful when it has been applied to the development of complex systems. Simulation should ensure that the hardware and software components of the human-telerobot interface have been designed and selected so that the operator's capabilities and limitations have been accommodated for since this is a complex system where few direct comparisons to existent systems can be made. Three broad areas of the human-telerobot interface where simulation can be of assistance are described. The use of simulation not only can result in a well-designed human-telerobot interface, but also can be used to ensure that components have been selected to best meet system's goals, and for operator training.

Telerobotics: A simulation facility for university research

NASA Technical Reports Server (NTRS)

Stark, L.; Kim, W.; Tendick, F.; Tyler, M.; Hannaford, B.; Barakat, W.; Bergengruen, O.; Braddi, L.; Eisenberg, J.; Ellis, S.

1987-01-01

An experimental telerobotics (TR) simulation suitable for studying human operator (H.O.) performance is described. Simple manipulator pick-and-place and tracking tasks allowed quantitative comparison of a number of calligraphic display viewing conditions. A number of control modes could be compared in this TR simulation, including displacement, rate and acceleratory control using position and force joysticks. A homeomorphic controller turned out to be no better than joysticks; the adaptive properties of the H.O. can apparently permit quite good control over a variety of controller configurations and control modes. Training by optimal control example seemed helpful in preliminary experiments. An introduced communication delay was found to produce decrease in performance. In considerable part, this difficulty could be compensated for by preview control information. That neurological control of normal human movement contains a data period of 0.2 second may relate to this robustness of H.O. control to delay. The Ames-Berkeley enhanced perspective display was utilized in conjunction with an experimental helmet mounted display system (HMD) that provided stereoscopic enhanced views.

Multi-arm multilateral haptics-based immersive tele-robotic system (HITS) for improvised explosive device disposal

NASA Astrophysics Data System (ADS)

Erickson, David; Lacheray, Hervé; Lai, Gilbert; Haddadi, Amir

2014-06-01

This paper presents the latest advancements of the Haptics-based Immersive Tele-robotic System (HITS) project, a next generation Improvised Explosive Device (IED) disposal (IEDD) robotic interface containing an immersive telepresence environment for a remotely-controlled three-articulated-robotic-arm system. While the haptic feedback enhances the operator's perception of the remote environment, a third teleoperated dexterous arm, equipped with multiple vision sensors and cameras, provides stereo vision with proper visual cues, and a 3D photo-realistic model of the potential IED. This decentralized system combines various capabilities including stable and scaled motion, singularity avoidance, cross-coupled hybrid control, active collision detection and avoidance, compliance control and constrained motion to provide a safe and intuitive control environment for the operators. Experimental results and validation of the current system are presented through various essential IEDD tasks. This project demonstrates that a two-armed anthropomorphic Explosive Ordnance Disposal (EOD) robot interface can achieve complex neutralization techniques against realistic IEDs without the operator approaching at any time.

Hand controller study of force and control mode

NASA Technical Reports Server (NTRS)

Morris, A. Terry

1992-01-01

The objectives are to compare and evaluate the utility and effectiveness of various input control devices, e.g., hand controllers, with respect to the relative importance of force and operation control mode (rate or position) for Space Station Freedom (SSF) related tasks. The topics are presented in viewgraph form and include the: Intelligent Research Systems Lab (ISRL) experimental design; Telerobotic Systems Research Laboratory (TSRL) final experimental design; and factor analysis summary of results.

Commercialization of JPL Virtual Reality calibration and redundant manipulator control technologies

NASA Technical Reports Server (NTRS)

Kim, Won S.; Seraji, Homayoun; Fiorini, Paolo; Brown, Robert; Christensen, Brian; Beale, Chris; Karlen, James; Eismann, Paul

1994-01-01

Within NASA's recent thrust for industrial collaboration, JPL (Jet Propulsion Laboratory) has recently established two technology cooperation agreements in the robotics area: one on virtual reality (VR) calibration with Deneb Robotics, Inc., and the other on redundant manipulator control with Robotics Research Corporation (RRC). These technology transfer cooperation tasks will enable both Deneb and RRC to commercialize enhanced versions of their products that will greatly benefit both space and terrestrial telerobotic applications.

Space teleoperations technology for Space Station evolution

NASA Technical Reports Server (NTRS)

Reuter, Gerald J.

1990-01-01

Viewgraphs on space teleoperations technology for space station evolution are presented. Topics covered include: shuttle remote manipulator system; mobile servicing center functions; mobile servicing center technology; flight telerobotic servicer-telerobot; flight telerobotic servicer technology; technologies required for space station assembly; teleoperation applications; and technology needs for space station evolution.

JPL space station telerobotic engineering prototype development FY 91 status/achievements

NASA Technical Reports Server (NTRS)

Zimmerman, Wayne

1991-01-01

The topics covered are presented in view graph form and include: (1) streamlining intravehicular activity (IVA) teleoperation activities on the Space Station Freedom (SSF); (2) enhancing SSF utilization during the man-tended phase; (3) telerobotic ground remote operations (TGRO); and (4) advanced telerobotics system technology (shared control).

The Space Station Freedom Flight Telerobotic Servicer - The design and evolution of a dexterous space robot

NASA Technical Reports Server (NTRS)

Mccain, Harry G.; Andary, James F.; Hewitt, Dennis R.; Haley, Dennis C.

1990-01-01

The Flight Telerobotic Servicer (FTS) will provide a telerobotic capability to the Space Station in the early assembly phases of the program and will be used for assembly, maintenance, and inspection throughout the lifetime of the Station. Here, the FTS design approach to the development of autonomous capabilities is discussed. The FTS telerobotic workstations for the Shuttle and Space Station, and facility for on-orbit storage are examined. The rationale of the FTS with regard to ease of operation, operational versatility, maintainability, safety, and control is discussed.

Human factors issues in telerobotic systems for Space Station Freedom servicing

NASA Technical Reports Server (NTRS)

Malone, Thomas B.; Permenter, Kathryn E.

1990-01-01

Requirements for Space Station Freedom servicing are described and the state-of-the-art for telerobotic system on-orbit servicing of spacecraft is defined. The projected requirements for the Space Station Flight Telerobotic Servicer (FTS) are identified. Finally, the human factors issues in telerobotic servicing are discussed. The human factors issues are basically three: the definition of the role of the human versus automation in system control; the identification of operator-device interface design requirements; and the requirements for development of an operator-machine interface simulation capability.

PC/AT-based architecture for shared telerobotic control

NASA Astrophysics Data System (ADS)

Schinstock, Dale E.; Faddis, Terry N.; Barr, Bill G.

1993-03-01

A telerobotic control system must include teleoperational, shared, and autonomous modes of control in order to provide a robot platform for incorporating the rapid advances that are occurring in telerobotics and associated technologies. These modes along with the ability to modify the control algorithms are especially beneficial for telerobotic control systems used for research purposes. The paper describes an application of the PC/AT platform to the control system of a telerobotic test cell. The paper provides a discussion of the suitability of the PC/AT as a platform for a telerobotic control system. The discussion is based on the many factors affecting the choice of a computer platform for a real time control system. The factors include I/O capabilities, simplicity, popularity, computational performance, and communication with external systems. The paper also includes a description of the actuation, measurement, and sensor hardware of both the master manipulator and the slave robot. It also includes a description of the PC-Bus interface cards. These cards were developed by the researchers in the KAT Laboratory, specifically for interfacing to the master manipulator and slave robot. Finally, a few different versions of the low level telerobotic control software are presented. This software incorporates shared control by supervisory systems and the human operator and traded control between supervisory systems and the human operator.

Concurrent Path Planning with One or More Humanoid Robots

NASA Technical Reports Server (NTRS)

Reiland, Matthew J. (Inventor); Sanders, Adam M. (Inventor)

2014-01-01

A robotic system includes a controller and one or more robots each having a plurality of robotic joints. Each of the robotic joints is independently controllable to thereby execute a cooperative work task having at least one task execution fork, leading to multiple independent subtasks. The controller coordinates motion of the robot(s) during execution of the cooperative work task. The controller groups the robotic joints into task-specific robotic subsystems, and synchronizes motion of different subsystems during execution of the various subtasks of the cooperative work task. A method for executing the cooperative work task using the robotic system includes automatically grouping the robotic joints into task-specific subsystems, and assigning subtasks of the cooperative work task to the subsystems upon reaching a task execution fork. The method further includes coordinating execution of the subtasks after reaching the task execution fork.

The WCSAR telerobotics test bed

NASA Technical Reports Server (NTRS)

Duffie, N.; Zik, J.; Teeter, R.; Crabb, T.

1988-01-01

Component technologies for use in telerobotic systems for space are being developed. As part of this effort, a test bed was established in which these technologies can be verified and integrated into telerobotic systems. The facility consists of two slave industrial robots, an articulated master arm controller, a cartesian coordinate master arm controller, and a variety of sensors, displays and stimulators for feedback to human operators. The controller of one of the slave robots remains in its commercial state, while the controller of the other robot has been replaced with a new controller that achieves high-performance in telerobotic operating modes. A dexterous slave hand which consists of two fingers and a thumb is being developed, along with a number of force-reflecting and non-force reflecting master hands, wrists and arms. A tactile sensing finger tip based on piezo-film technology has been developed, along with tactile stimulators and CAD-based displays for sensory feedback and sensory substitution. The telerobotics test bed and its component technologies are described, as well as the integration of these component technologies into telerobotic systems, and their performance in conjunction with human operators.

Results of telerobotic hand controller study using force information and rate control

NASA Technical Reports Server (NTRS)

Willshire, Kelli F.; Harrison, F. W.; Hogge, Edward F.; Williams, Robert L.; Soloway, Donald

1992-01-01

To increase quantified information about the effectiveness and subjective workload of force information relayed through manipulator input control devices, a space related task was performed by eight subjects with kinesthetic force feedback and/or local force accommodation through three different input control devices (i.e., hand controllers) operating in rate control mode. Task completion time, manipulator work, and subjective responses were measured. Results indicated a difference among the hand controllers. For the Honeywell six degree-of-freedom hand controller, the overall task completion times were shortest, the amount of work exerted was the least, and was the most preferred by test subjects. Neither force accommodation with or without reflection resulted in shorter task completion times or reduced work although those conditions were better than no force information for some aspects. Comparisons of results from previous studies are discussed.

Low-Latency Lunar Surface Telerobotics from Earth-Moon Libration Points

NASA Technical Reports Server (NTRS)

Lester, Daniel; Thronson, Harley

2011-01-01

Concepts for a long-duration habitat at Earth-Moon LI or L2 have been advanced for a number of purposes. We propose here that such a facility could also have an important role for low-latency telerobotic control of lunar surface equipment, both for lunar science and development. With distances of about 60,000 km from the lunar surface, such sites offer light-time limited two-way control latencies of order 400 ms, making telerobotic control for those sites close to real time as perceived by a human operator. We point out that even for transcontinental teleoperated surgical procedures, which require operational precision and highly dexterous manipulation, control latencies of this order are considered adequate. Terrestrial telerobots that are used routinely for mining and manufacturing also involve control latencies of order several hundred milliseconds. For this reason, an Earth-Moon LI or L2 control node could build on the technology and experience base of commercially proven terrestrial ventures. A lunar libration-point telerobotic node could demonstrate exploration strategies that would eventually be used on Mars, and many other less hospitable destinations in the solar system. Libration-point telepresence for the Moon contrasts with lunar telerobotic control from the Earth, for which two-way control latencies are at least six times longer. For control latencies that long, telerobotic control efforts are of the "move-and-wait" variety, which is cognitively inferior to near real-time control.

Space telerobotic systems: Applications and concepts

NASA Technical Reports Server (NTRS)

Jenkins, L.

1987-01-01

The definition of a variety of assembly, servicing, and maintenance missions has led to the generation of a number of space telerobot concepts. The remote operation of a space telerobot is seen as a means to increase astronaut productivity. Dexterous manipulator arms are controlled from the Space Shuttle Orbiter cabin or a Space Station module. Concepts for the telerobotic work system have been developed by the Lyndon B. Johnson Space Center through contracts with the Grumman Aerospace Corporation and Marin Marietta Corporation. These studies defined a concept for a telerobot with extravehicular activity (EVA) astronaut equivalent capability that would be controlled from the Space Shuttle. An evolutionary development of the system is proposed as a means of incorporating technology advances. Early flight testing is seen as needed to address the uncertainties of robotic manipulation in space. Space robotics can be expected to spin off technology to terrestrial robots, particularly in hazardous and unstructured applications.

Technology Demonstration Missions

NASA Technical Reports Server (NTRS)

McDougal, John; French, Raymond; Adams-Fogle, Beth; Stephens, Karen

2015-01-01

Technology Demonstration Missions (TDM) is in its third year of execution, being initiated in 2010 and baselined in January of 2012. There are 11 projects that NASA Marshall Space Flight Center (MSFC) has contributed to or led: (1) Evolvable Cryogenics (eCryo): Cyrogenic Propellant Storage and Transfer Engineering Development Unit (EDU), a proof of manufacturability effort, used to enhance knowledge and technology related to handling cryogenic propellants, specifically liquid hydrogen. (2) Composites for Exploration Upper Stage (CEUS): Design, build, test, and address flight certification of a large composite shell suitable for the second stage of the Space Launch System (SLS). (3) Deep Space Atomic Clock (DSAC): Spaceflight to demo small, low-mass atomic clock that can provide unprecedented stability for deep space navigation. (4) Green Propellant Infusion Mission (GPIM): Demo of high-performance, green propellant propulsion system suitable for Evolved Expendable Launch Vehicle (EELV) Secondary Payload Adapter (ESPA)-class spacecraft. (5) Human Exploration Telerobotics (HET): Demonstrating how telerobotics, remote control of a variety of robotic systems, can take routine, highly repetitive, dangerous or long-duration tasks out of human hands. (6) Laser Communication Relay Demo (LCRD): Demo to advance optical communications technology toward infusion into deep space and near Earth operational systems, while growing the capabilities of industry sources. (7) Low Density Supersonic Decelerator (LDSD): Demo new supersonic inflatable decelerator and parachute technologies to enable Mars landings of larger payloads with greater precision at a wider range of altitudes. (8) Mars Science Laboratory (MSL) Entry Descent & Landing Instrumentation (MEDLI): Demo of embedded sensors embedded in the MSL heat shield, designed to record the heat and atmospheric pressure experienced during the spacecraft's high-speed, hot entry in the Martian atmosphere. (9) Solar Electric Propulsion (SEP): 50-kW class spacecraft that uses flexible blanket solar arrays for power generation and an electric propulsion system that delivers payload from low-Earth orbit to higher orbits. (10) Solar Sail Demonstration (SSD): Demo to validate sail deployment techniques for solar sails that are propelled by the pressure of sunlight. (11) Terrestrial HIAD Orbit Reentry (THOR): Demo of a 3.7-m Hypersonic Inflatable Aerodynamic Decelerator (HIAD) entry vehicle to test second generation aerothermal performance and modeling.

Weighted feature selection criteria for visual servoing of a telerobot

NASA Technical Reports Server (NTRS)

Feddema, John T.; Lee, C. S. G.; Mitchell, O. R.

1989-01-01

Because of the continually changing environment of a space station, visual feedback is a vital element of a telerobotic system. A real time visual servoing system would allow a telerobot to track and manipulate randomly moving objects. Methodologies for the automatic selection of image features to be used to visually control the relative position between an eye-in-hand telerobot and a known object are devised. A weighted criteria function with both image recognition and control components is used to select the combination of image features which provides the best control. Simulation and experimental results of a PUMA robot arm visually tracking a randomly moving carburetor gasket with a visual update time of 70 milliseconds are discussed.

Proceedings of the NASA Conference on Space Telerobotics, volume 2

NASA Technical Reports Server (NTRS)

Rodriguez, Guillermo (Editor); Seraji, Homayoun (Editor)

1989-01-01

These proceedings contain papers presented at the NASA Conference on Space Telerobotics held in Pasadena, January 31 to February 2, 1989. The theme of the Conference was man-machine collaboration in space. The Conference provided a forum for researchers and engineers to exchange ideas on the research and development required for application of telerobotics technology to the space systems planned for the 1990s and beyond. The Conference: (1) provided a view of current NASA telerobotic research and development; (2) stimulated technical exchange on man-machine systems, manipulator control, machine sensing, machine intelligence, concurrent computation, and system architectures; and (3) identified important unsolved problems of current interest which can be dealt with by future research.

High performance bilateral telerobot control.

PubMed

Kline-Schoder, Robert; Finger, William; Hogan, Neville

2002-01-01

Telerobotic systems are used when the environment that requires manipulation is not easily accessible to humans, as in space, remote, hazardous, or microscopic applications or to extend the capabilities of an operator by scaling motions and forces. The Creare control algorithm and software is an enabling technology that makes possible guaranteed stability and high performance for force-feedback telerobots. We have developed the necessary theory, structure, and software design required to implement high performance telerobot systems with time delay. This includes controllers for the master and slave manipulators, the manipulator servo levels, the communication link, and impedance shaping modules. We verified the performance using both bench top hardware as well as a commercial microsurgery system.

Simulation of the human-telerobot interface on the Space Station

NASA Technical Reports Server (NTRS)

Stuart, Mark A.; Smith, Randy L.

1993-01-01

Many issues remain unresolved concerning the components of the human-telerobot interface presented in this work. It is critical that these components be optimally designed and arranged to ensure, not only that the overall system's goals are met, but but that the intended end-user has been optimally accommodated. With sufficient testing and evaluation throughout the development cycle, the selection of the components to use in the final telerobotic system can promote efficient, error-free performance. It is recommended that whole-system simulation with full-scale mockups be used to help design the human-telerobot interface. It is contended that the use of simulation can facilitate this design and evaluation process.

A decade of telerobotics in rehabilitation: Demonstrated utility blocked by the high cost of manipulation and the complexity of the user interface

NASA Technical Reports Server (NTRS)

Leifer, Larry; Michalowski, Stefan; Vanderloos, Machiel

1991-01-01

The Stanford/VA Interactive Robotics Laboratory set out in 1978 to test the hypothesis that industrial robotics technology could be applied to serve the manipulation needs of severely impaired individuals. Five generations of hardware, three generations of system software, and over 125 experimental subjects later, we believe that genuine utility is achievable. The experience includes development of over 65 task applications using voiced command, joystick control, natural language command and 3D object designation technology. A brief foray into virtual environments, using flight simulator technology, was instructive. If reality and virtuality come for comparable prices, you cannot beat reality. A detailed review of assistive robot anatomy and the performance specifications needed to achieve cost/beneficial utility will be used to support discussion of the future of rehabilitation telerobotics. Poised on the threshold of commercial viability, but constrained by the high cost of technically adequate manipulators, this worthy application domain flounders temporarily. In the long run, it will be the user interface that governs utility.

Evaluation of a telerobotic system to assist surgeons in microsurgery

NASA Technical Reports Server (NTRS)

Das, H.; Zak, H.; Johnson, J.; Crouch, J.; Frambach, D.

1999-01-01

A tool was developed that assists surgeons in manipulating surgical instruments more precisely than is possible manually. The tool is a telemanipulator that scales down the surgeon's hand motion and filters tremor in the motion. The signals measured from the surgeon's hand are transformed and used to drive a six-degrees-of-freedom robot to position the surgical instrument mounted on its tip. A pilot study comparing the performance of the telemanipulator system against manual instrument positioning was conducted at the University of Southern California School of Medicine. The results show that a telerobotic tool can improve the performance of a microsurgeon by increasing the precision with which he can position surgical instruments, but this is achieved at the cost of increased time in performing the task. We believe that this technology will extend the capabilities of microsurgeons and allow more surgeons to perform highly skilled procedures currently performed only by the best surgeons. It will also enable performance of new surgical procedures that are beyond the capabilities of even the most skilled surgeons. Copyright 1999 Wiley-Liss, Inc.

MIT research in telerobotics

NASA Technical Reports Server (NTRS)

Sheridan, T. B.

1987-01-01

Ongoing MIT research in telerobotics (vehicles capable of some autonomous sensing and manipulating, having some remote supervisory control by people) and teleoperation (vehicles for sensing and manipulating which are fully controlled remotely by people) is discussed. The current efforts mix human and artificial intelligence/control. The idea of adjustable impedance at either end of pure master-slave teleoperation, and simultaneous coordinated control of teleoperator/telerobotic systems which have more than six degrees of freedom (e.g., a combined vehicle and arm, each with five or six DOF) are discussed. A new cable-controlled parallel link arm which offers many advantages over conventional arms for space is briefly described. Predictor displays to compensate for time delay in teleoperator loops, the use of state estimation to help human control decisions in space, and ongoing research in supervisory command language are covered. Finally, efforts to build a human flyable real-time dynamic computer-graphic telerobot simulator are described. These projects represent most, but not all, of the telerobotics research in our laboratory, supported by JPL, NASA Ames and NOAA.

Anthropomorphic teleoperation: Controlling remote manipulators with the DataGlove

NASA Technical Reports Server (NTRS)

Hale, J. P., II

1992-01-01

A two phase effort was conducted to assess the capabilities and limitations of the DataGlove, a lightweight glove input device that can output signals in real-time based on hand shape, orientation, and movement. The first phase was a period for system integration, checkout, and familiarization in a virtual environment. The second phase was a formal experiment using the DataGlove as input device to control the protoflight manipulator arm (PFMA) - a large telerobotic arm with an 8-ft reach. The first phase was used to explore and understand how the DataGlove functions in a virtual environment, build a virtual PFMA, and consider and select a reasonable teleoperation control methodology. Twelve volunteers (six males and six females) participated in a 2 x 3 (x 2) full-factorial formal experiment using the DataGlove to control the PFMA in a simple retraction, slewing, and insertion task. Two within-subjects variables, time delay (0, 1, and 2 seconds) and PFMA wrist flexibility (rigid/flexible), were manipulated. Gender served as a blocking variable. A main effect of time delay was found for slewing and total task times. Correlations among questionnaire responses, and between questionnaire responses and session mean scores and gender were computed. The experimental data were also compared with data collected in another study that used a six degree-of-freedom handcontroller to control the PFMA in the same task. It was concluded that the DataGlove is a legitimate teleoperations input device that provides a natural, intuitive user interface. From an operational point of view, it compares favorably with other 'standard' telerobotic input devices and should be considered in future trades in teleoperation systems' designs.

Test Bed For Telerobots

NASA Technical Reports Server (NTRS)

Matijevic, Jacob R.; Zimmerman, Wayne F.; Dolinsky, Shlomo

1990-01-01

Assembly of electromechanical and electronic equipment (including computers) constitutes test bed for development of advanced robotic systems for remote manipulation. Combines features not found in commercial systems. Its architecture allows easy growth in complexity and level of automation. System national resource for validation of new telerobotic technology. Intended primarily for robots used in outer space, test bed adapted to development of advanced terrestrial telerobotic systems for handling radioactive materials, dangerous chemicals, and explosives.

Human Exploration Using Real-Time Robotic Operations (HERRO)- Crew Telerobotic Control Vehicle (CTCV) Design

NASA Technical Reports Server (NTRS)

Oleson, Steven R.; McGuire, Melissa L.; Burke, Laura; Chato, David; Fincannon, James; Landis, Geoff; Sandifer, Carl; Warner, Joe; Williams, Glenn; Colozza, Tony;

Estimating the executive demands of a one-back choice reaction time task by means of the selective interference paradigm.

PubMed

Szmalec, Arnaud; Vandierendonck, André

2007-08-01

The present study proposes a new executive task, the one-back choice reaction time (RT) task, and implements the selective interference paradigm to estimate the executive demands of the processing components involved in this task. Based on the similarities between a one-back choice RT task and the n-back updating task, it was hypothesized that one-back delaying of a choice reaction involves executive control. In three experiments, framed within Baddeley's (1986) working-memory model, a one-back choice RT task, a choice RT task, articulatory suppression, and matrix tapping were performed concurrently with primary tasks involving verbal, visuospatial, and executive processing. The results demonstrate that one-back delaying of a choice reaction interferes with tasks requiring executive control, while the potential interference at the level of the verbal or visuospatial working memory slave systems remains minimal.

Self-assembling software generator

DOEpatents

Bouchard, Ann M [Albuquerque, NM; Osbourn, Gordon C [Albuquerque, NM

2011-11-25

A technique to generate an executable task includes inspecting a task specification data structure to determine what software entities are to be generated to create the executable task, inspecting the task specification data structure to determine how the software entities will be linked after generating the software entities, inspecting the task specification data structure to determine logic to be executed by the software entities, and generating the software entities to create the executable task.

Rover and Telerobotics Technology Program

NASA Technical Reports Server (NTRS)

Weisbin, Charles R.

1998-01-01

The Jet Propulsion Laboratory's (JPL's) Rover and Telerobotics Technology Program, sponsored by the National Aeronautics and Space Administration (NASA), responds to opportunities presented by NASA space missions and systems, and seeds commerical applications of the emerging robotics technology. The scope of the JPL Rover and Telerobotics Technology Program comprises three major segments of activity: NASA robotic systems for planetary exploration, robotic technology and terrestrial spin-offs, and technology for non-NASA sponsors. Significant technical achievements have been reached in each of these areas, including complete telerobotic system prototypes that have built and tested in realistic scenarios relevant to prospective users. In addition, the program has conducted complementary basic research and created innovative technology and terrestrial applications, as well as enabled a variety of commercial spin-offs.

The Charlotte (TM) intra-vehicular robot

NASA Technical Reports Server (NTRS)

Swaim, Patrick L.; Thompson, Clark J.; Campbell, Perry D.

1994-01-01

NASA has identified telerobotics and telescience as essential technologies to reduce the crew extra-vehicular activity (EVA) and intra-vehicular activity (IVA) workloads. Under this project, we are developing and flight testing a novel IVA robot to relieve the crew of tedious and routine tasks. Through ground telerobotic control of this robot, we will enable ground researchers to routinely interact with experiments in space. Our approach is to develop an IVA robot system incrementally by employing a series of flight tests with increasing complexity. This approach has the advantages of providing an early IVA capability that can assist the crew, demonstrate capabilities that ground researchers can be confident of in planning for future experiments, and allow incremental refinement of system capabilities and insertion of new technology. In parallel with this approach to flight testing, we seek to establish ground test beds, in which the requirements of payload experimenters can be further investigated. In 1993 we reviewed manifested SpaceHab experiments and defined IVA robot requirements to assist in their operation. We also examined previous IVA robot designs and assessed them against flight requirements. We rejected previous design concepts on the basis of threat to crew safety, operability, and maintainability. Based on this insight, we developed an entirely new concept for IVA robotics, the CHARLOTTE robot system. Ground based testing of a prototype version of the system has already proven its ability to perform most common tasks demanded of the crew, including operation of switches, buttons, knobs, dials, and performing video surveys of experiments and switch panels.

[Ecologic evaluation in the cognitive assessment of brain injury patients: generation and execution of script].

PubMed

Baguena, N; Thomas-Antérion, C; Sciessere, K; Truche, A; Extier, C; Guyot, E; Paris, N

2006-06-01

Assessment of executive functions in an everyday life activity, evaluating brain injury subjects with script generation and execution tasks. We compared a script generation task to a script execution task, whereby subjects had to make a cooked dish. Two grids were used for the quotation, qualitative and quantitative, as well as the calculation of an anosognosis score. We checked whether the execution task was more sensitive to a dysexecutive disorder than the script generation task and compared the scores obtained in this evaluation with those from classical frontal tests. Twelve subjects with brain injury 6 years+/-4.79 ago and 12 healthy control subjects were tested. The subjects carried out a script generation task whereby they had to explain the necessary stages to make a chocolate cake. They also had to do a script execution task corresponding to the cake making. The 2 quotation grids were operational and complementary. The quantitative grid is more sensitive to a dysexecutive disorder. The brain injury subjects made more errors in the execution task. It is important to evaluate the executive functions of subjects with brain injury in everyday life tasks, not just in psychometric or script-generation tests. Indeed the ecological realization of a very simple task can reveal executive function difficulties such as the planning or the sequencing of actions, which are under-evaluated in laboratory tests.

Low-Latency Science Exploration of Planetary Bodies: How ISS Might Be Used as Part of a Low-Latency Analog Campaign for Human Exploration

NASA Technical Reports Server (NTRS)

Thronson, Harley; Valinia, Azita; Bleacher, Jacob; Eigenbrode, Jennifer; Garvin, Jim; Petro, Noah

2014-01-01

We suggest that the International Space Station be used to examine the application and validation of low-latency telepresence for surface exploration from space as an alternative, precursor, or potentially as an adjunct to astronaut "boots on the ground." To this end, controlled experiments that build upon and complement ground-based analog field studies will be critical for assessing the effects of different latencies (0 to 500 milliseconds), task complexity, and alternate forms of feedback to the operator. These experiments serve as an example of a pathfinder for NASA's roadmap of missions to Mars with low-latency telerobotic exploration as a precursor to astronaut's landing on the surface to conduct geological tasks.

Low-latency Science Exploration of Planetary Bodies: a Demonstration Using ISS in Support of Mars Human Exploration

NASA Technical Reports Server (NTRS)

Thronson, Harley A.; Valinia, Azita; Bleacher, Jacob; Eigenbrode, Jennifer; Garvin, Jim; Petro, Noah

2014-01-01

We summarize a proposed experiment to use the International Space Station to formally examine the application and validation of low-latency telepresence for surface exploration from space as an alternative, precursor, or potentially as an adjunct to astronaut "boots on the ground." The approach is to develop and propose controlled experiments, which build upon previous field studies and which will assess the effects of different latencies (0 to 500 msec), task complexity, and alternate forms of feedback to the operator. These experiments serve as an example of a pathfinder for NASA's roadmap of missions to Mars with low-latency telerobotic exploration as a precursor to astronaut's landing on the surface to conduct geological tasks.

Space Telerobotics and Rover Research at JPL

NASA Technical Reports Server (NTRS)

Weisbin, C.; Hayati, S.; Rodriguez, G.

1995-01-01

The goal of our program is to develop, integrate and demonstrate the science and technology of remote telerobotics leading to increases in operational capability, safety, cost effectiveness and probability of success of NASA missions. To that end, the program fosters the development of innovative system concepts for on-orbit servicing and planetary surface missions which use telerobotic systems as an important central component. These concepts are carried forward into develoments which are used to evaluate and demonstrate technology in realistic flight and ground experiments.

Assessment of planning abilities in individuals with mild cognitive impairment using an open-ended problem-solving task.

PubMed

Sanders, Chad; Low, Christina; Schmitter-Edgecombe, Maureen

2014-01-01

There is currently limited research evaluating planning abilities, a core subcomponent of executive functioning, in individuals with mild cognitive impairment (MCI). In the present study, we utilized the "Amap Task," an open-ended problem-solving task, to separately evaluate the formulation and execution components of planning ability in individuals with MCI. Thirty-seven cognitively healthy older adults and 37 individuals with MCI used a map layout of a university apartment to develop and write out a strategy (formulation stage) to successfully complete a list of tasks (e.g., retrieve and fill a water pitcher before placing it in the refrigerator). Subsequently, participants carried out the tasks in the apartment with the aid of their formulated plan (execution stage). MCI participants performed more poorly than older adult (OA) controls during both the formulation and execution stages on measures of task accuracy and task efficiency. However, both groups were able to adjust and improve task accuracy and efficiency from formulation to task execution. Finally, MCI participants took significantly longer to complete the task and adhered less to their formulated plans during task completion. Using an open-ended problem-solving task, the findings revealed that individuals with MCI experienced difficulties with both the formulation and execution components of planning. Like controls, participants with MCI were able to successfully modify their plan online, improving their performance from task formulation to task execution.

Poorer divided attention in children born very preterm can be explained by difficulty with each component task, not the executive requirement to dual-task.

PubMed

Delane, Louise; Campbell, Catherine; Bayliss, Donna M; Reid, Corinne; Stephens, Amelia; French, Noel; Anderson, Mike

2017-07-01

Children born very preterm (VP, ≤ 32 weeks) exhibit poor performance on tasks of executive functioning. However, it is largely unknown whether this reflects the cumulative impact of non-executive deficits or a separable impairment in executive-level abilities. A dual-task paradigm was used in the current study to differentiate the executive processes involved in performing two simple attention tasks simultaneously. The executive-level contribution to performance was indexed by the within-subject cost incurred to single-task performance under dual-task conditions, termed dual-task cost. The participants included 77 VP children (mean age: 7.17 years) and 74 peer controls (mean age: 7.16 years) who completed Sky Search (selective attention), Score (sustained attention) and Sky Search DT (divided attention) from the Test of Everyday Attention for Children. The divided-attention task requires the simultaneous performance of the selective- and sustained-attention tasks. The VP group exhibited poorer performance on the selective- and divided-attention tasks, and showed a strong trend toward poorer performance on the sustained-attention task. However, there were no significant group differences in dual-task cost. These results suggest a cumulative impact of vulnerable lower-level cognitive processes on dual-tasking or divided attention in VP children, and fail to support the hypothesis that VP children show a separable impairment in executive-level abilities.

Development and verification of ground-based tele-robotics operations concept for Dextre

NASA Astrophysics Data System (ADS)

Aziz, Sarmad

2013-05-01

The Special Purpose Dextreous Manipulator (Dextre) is the latest addition to the on-orbit segment of the Mobile Servicing System (MSS); Canada's contribution to the International Space Station (ISS). Launched in March 2008, the advanced two-armed robot is designed to perform various ISS maintenance tasks on robotically compatible elements and on-orbit replaceable units using a wide variety of tools and interfaces. The addition of Dextre has increased the capabilities of the MSS, and has introduced significant complexity to ISS robotics operations. While the initial operations concept for Dextre was based on human-in-the-loop control by the on-orbit astronauts, the complexities of robotic maintenance and the associated costs of training and maintaining the operator skills required for Dextre operations demanded a reexamination of the old concepts. A new approach to ISS robotic maintenance was developed in order to utilize the capabilities of Dextre safely and efficiently, while at the same time reducing the costs of on-orbit operations. This paper will describe the development, validation, and on-orbit demonstration of the operations concept for ground-based tele-robotics control of Dextre. It will describe the evolution of the new concepts from the experience gained from the development and implementation of the ground control capability for the Space Station Remote Manipulator System; Canadarm 2. It will discuss the various technical challenges faced during the development effort, such as requirements for high positioning accuracy, force/moment sensing and accommodation, failure tolerance, complex tool operations, and the novel operational tools and techniques developed to overcome them. The paper will also describe the work performed to validate the new concepts on orbit and will discuss the results and lessons learned from the on-orbit checkout and commissioning of Dextre using the newly developed tele-robotics techniques and capabilities.

Relations between Short-term Memory Deficits, Semantic Processing, and Executive Function

PubMed Central

Allen, Corinne M.; Martin, Randi C.; Martin, Nadine

2012-01-01

Background Previous research has suggested separable short-term memory (STM) buffers for the maintenance of phonological and lexical-semantic information, as some patients with aphasia show better ability to retain semantic than phonological information and others show the reverse. Recently, researchers have proposed that deficits to the maintenance of semantic information in STM are related to executive control abilities. Aims The present study investigated the relationship of executive function abilities with semantic and phonological short-term memory (STM) and semantic processing in such patients, as some previous research has suggested that semantic STM deficits and semantic processing abilities are critically related to specific or general executive function deficits. Method and Procedures 20 patients with aphasia and STM deficits were tested on measures of short-term retention, semantic processing, and both complex and simple executive function tasks. Outcome and Results In correlational analyses, we found no relation between semantic STM and performance on simple or complex executive function tasks. In contrast, phonological STM was related to executive function performance in tasks that had a verbal component, suggesting that performance in some executive function tasks depends on maintaining or rehearsing phonological codes. Although semantic STM was not related to executive function ability, performance on semantic processing tasks was related to executive function, perhaps due to similar executive task requirements in both semantic processing and executive function tasks. Conclusions Implications for treatment and interpretations of executive deficits are discussed. PMID:22736889

A design fix to supervisory control for fault-tolerant scheduling of real-time multiprocessor systems with aperiodic tasks

NASA Astrophysics Data System (ADS)

Devaraj, Rajesh; Sarkar, Arnab; Biswas, Santosh

2015-11-01

In the article 'Supervisory control for fault-tolerant scheduling of real-time multiprocessor systems with aperiodic tasks', Park and Cho presented a systematic way of computing a largest fault-tolerant and schedulable language that provides information on whether the scheduler (i.e., supervisor) should accept or reject a newly arrived aperiodic task. The computation of such a language is mainly dependent on the task execution model presented in their paper. However, the task execution model is unable to capture the situation when the fault of a processor occurs even before the task has arrived. Consequently, a task execution model that does not capture this fact may possibly be assigned for execution on a faulty processor. This problem has been illustrated with an appropriate example. Then, the task execution model of Park and Cho has been modified to strengthen the requirement that none of the tasks are assigned for execution on a faulty processor.

Decision-making under risk conditions is susceptible to interference by a secondary executive task.

PubMed

Starcke, Katrin; Pawlikowski, Mirko; Wolf, Oliver T; Altstötter-Gleich, Christine; Brand, Matthias

2011-05-01

Recent research suggests two ways of making decisions: an intuitive and an analytical one. The current study examines whether a secondary executive task interferes with advantageous decision-making in the Game of Dice Task (GDT), a decision-making task with explicit and stable rules that taps executive functioning. One group of participants performed the original GDT solely, two groups performed either the GDT and a 1-back or a 2-back working memory task as a secondary task simultaneously. Results show that the group which performed the GDT and the secondary task with high executive load (2-back) decided less advantageously than the group which did not perform a secondary executive task. These findings give further evidence for the view that decision-making under risky conditions taps into the rational-analytical system which acts in a serial and not parallel way as performance on the GDT is disturbed by a parallel task that also requires executive resources.

Age differences in high frequency phasic heart rate variability and performance response to increased executive function load in three executive function tasks

PubMed Central

Byrd, Dana L.; Reuther, Erin T.; McNamara, Joseph P. H.; DeLucca, Teri L.; Berg, William K.

2015-01-01

The current study examines similarity or disparity of a frontally mediated physiological response of mental effort among multiple executive functioning tasks between children and adults. Task performance and phasic heart rate variability (HRV) were recorded in children (6 to 10 years old) and adults in an examination of age differences in executive functioning skills during periods of increased demand. Executive load levels were varied by increasing the difficulty levels of three executive functioning tasks: inhibition (IN), working memory (WM), and planning/problem solving (PL). Behavioral performance decreased in all tasks with increased executive demand in both children and adults. Adults’ phasic high frequency HRV was suppressed during the management of increased IN and WM load. Children’s phasic HRV was suppressed during the management of moderate WM load. HRV was not suppressed during either children’s or adults’ increasing load during the PL task. High frequency phasic HRV may be most sensitive to executive function tasks that have a time-response pressure, and simply requiring performance on a self-paced task requiring frontal lobe activation may not be enough to generate HRV responsitivity to increasing demand. PMID:25798113

A university teaching simulation facility

NASA Technical Reports Server (NTRS)

Stark, Lawrence; Kim, Won-Soo; Tendick, Frank; Tyler, Mitchell; Hannaford, Blake; Barakat, Wissam; Bergengruen, Olaf; Braddi, Louis; Eisenberg, Joseph; Ellis, Stephen

1987-01-01

An experimental telerobotics (TR) simulation is described suitable for studying human operator (HO) performance. Simple manipulator pick-and-place and tracking tasks allowed quantitative comparison of a number of calligraphic display viewing conditions. A number of control modes could be compared in this TR simulation, including displacement, rate, and acceleratory control using position and force joysticks. A homeomorphic controller turned out to be no better than joysticks; the adaptive properties of the HO can apparently permit quite good control over a variety of controller configurations and control modes. Training by optimal control example seemed helpful in preliminary experiments.

Central executive involvement in children's spatial memory.

PubMed

Ang, Su Yin; Lee, Kerry

2008-11-01

Previous research with adults found that spatial short-term and working memory tasks impose similar demands on executive resources. We administered spatial short-term and working memory tasks to 8- and 11-year-olds in three separate experiments. In Experiments 1 and 2 an executive suppression task (random number generation) was found to impair performances on a short-term memory task (Corsi blocks), a working memory task (letter rotation), and a spatial visualisation task (paper folding). In Experiment 3 an articulatory suppression task only impaired performance on the working memory task. These results suggest that short-term and working memory performances are dependent on executive resources. The degree to which the short-term memory task was dependent on executive resources was expected to be related to the amount of experience children have had with such tasks. Yet we found no significant age-related suppression effects. This was attributed to differences in employment of cognitive strategies by the older children.

A Telerobot to Extend the Skill of Microsurgeons

NASA Technical Reports Server (NTRS)

Das, H.; Ohm, T.; Boswell, C.; Rodriguez, G.; Steele, R.; Charles, S.

1998-01-01

The engineering details of the Robot Assisted MicroSurgery (RAMS) telerobotic system designed to assist microsurgeons improve the precision and dexterity with which they can position surgical instruments is described in this paper.

An Execution Service for Grid Computing

NASA Technical Reports Server (NTRS)

Smith, Warren; Hu, Chaumin

2004-01-01

This paper describes the design and implementation of the IPG Execution Service that reliably executes complex jobs on a computational grid. Our Execution Service is part of the IPG service architecture whose goal is to support location-independent computing. In such an environment, once n user ports an npplicntion to one or more hardware/software platfrms, the user can describe this environment to the grid the grid can locate instances of this platfrm, configure the platfrm as required for the application, and then execute the application. Our Execution Service runs jobs that set up such environments for applications and executes them. These jobs consist of a set of tasks for executing applications and managing data. The tasks have user-defined starting conditions that allow users to specih complex dependencies including task to execute when tasks fail, afiequent occurrence in a large distributed system, or are cancelled. The execution task provided by our service also configures the application environment exactly as specified by the user and captures the exit code of the application, features that many grid execution services do not support due to dflculties interfacing to local scheduling systems.

From an Executive Network to Executive Control: A Computational Model of the "n"-Back Task

ERIC Educational Resources Information Center

Chatham, Christopher H.; Herd, Seth A.; Brant, Angela M.; Hazy, Thomas E.; Miyake, Akira; O'Reilly, Randy; Friedman, Naomi P.

2011-01-01

A paradigmatic test of executive control, the n-back task, is known to recruit a widely distributed parietal, frontal, and striatal "executive network," and is thought to require an equally wide array of executive functions. The mapping of functions onto substrates in such a complex task presents a significant challenge to any theoretical…

Do tasks make a difference? Accounting for heterogeneity of performance of children with reading difficulties on tasks of executive function: findings from a meta-analysis.

PubMed

Booth, Josephine N; Boyle, James M E; Kelly, Steve W

2010-03-01

Research studies have implicated executive functions in reading difficulties (RD). But while some studies have found children with RD to be impaired on tasks of executive function other studies report unimpaired performance. A meta-analysis was carried out to determine whether these discrepant findings can be accounted for by differences in the tasks of executive function that are utilized. A total of 48 studies comparing the performance on tasks of executive function of children with RD with their typically developing peers were included in the meta-analysis, yielding 180 effect sizes. An overall effect size of 0.57 (SE .03) was obtained, indicating that children with RD have impairments on tasks of executive function. However, effect sizes varied considerably suggesting that the impairment is not uniform. Moderator analysis revealed that task modality and IQ-achievement discrepancy definitions of RD influenced the magnitude of effect; however, the age and gender of participants and the nature of the RD did not have an influence. While the children's RD were associated with executive function impairments, variation in effect size is a product of the assessment task employed, underlying task demands, and definitional criteria.

Human Space Exploration and Human Space Flight: Latency and the Cognitive Scale of the Universe

NASA Technical Reports Server (NTRS)

Lester, Dan; Thronson, Harley

2011-01-01

The role of telerobotics in space exploration as placing human cognition on other worlds is limited almost entirely by the speed of light, and the consequent communications latency that results from large distances. This latency is the time delay between the human brain at one end, and the telerobotic effector and sensor at the other end. While telerobotics and virtual presence is a technology that is rapidly becoming more sophisticated, with strong commercial interest on the Earth, this time delay, along with the neurological timescale of a human being, quantitatively defines the cognitive horizon for any locale in space. That is, how distant can an operator be from a robot and not be significantly impacted by latency? We explore that cognitive timescale of the universe, and consider the implications for telerobotics, human space flight, and participation by larger numbers of people in space exploration. We conclude that, with advanced telepresence, sophisticated robots could be operated with high cognition throughout a lunar hemisphere by astronauts within a station at an Earth-Moon Ll or L2 venue. Likewise, complex telerobotic servicing of satellites in geosynchronous orbit can be carried out from suitable terrestrial stations.

Medical telerobotic systems: current status and future trends.

PubMed

Avgousti, Sotiris; Christoforou, Eftychios G; Panayides, Andreas S; Voskarides, Sotos; Novales, Cyril; Nouaille, Laurence; Pattichis, Constantinos S; Vieyres, Pierre

2016-08-12

Teleoperated medical robotic systems allow procedures such as surgeries, treatments, and diagnoses to be conducted across short or long distances while utilizing wired and/or wireless communication networks. This study presents a systematic review of the relevant literature between the years 2004 and 2015, focusing on medical teleoperated robotic systems which have witnessed tremendous growth over the examined period. A thorough insight of telerobotics systems discussing design concepts, enabling technologies (namely robotic manipulation, telecommunications, and vision systems), and potential applications in clinical practice is provided, while existing limitations and future trends are also highlighted. A representative paradigm of the short-distance case is the da Vinci Surgical System which is described in order to highlight relevant issues. The long-distance telerobotics concept is exemplified through a case study on diagnostic ultrasound scanning. Moreover, the present review provides a classification into short- and long-distance telerobotic systems, depending on the distance from which they are operated. Telerobotic systems are further categorized with respect to their application field. For the reviewed systems are also examined their engineering characteristics and the employed robotics technology. The current status of the field, its significance, the potential, as well as the challenges that lie ahead are thoroughly discussed.

Advanced data management design for autonomous telerobotic systems in space using spaceborne symbolic processors

NASA Technical Reports Server (NTRS)

Goforth, Andre

1987-01-01

The use of computers in autonomous telerobots is reaching the point where advanced distributed processing concepts and techniques are needed to support the functioning of Space Station era telerobotic systems. Three major issues that have impact on the design of data management functions in a telerobot are covered. It also presents a design concept that incorporates an intelligent systems manager (ISM) running on a spaceborne symbolic processor (SSP), to address these issues. The first issue is the support of a system-wide control architecture or control philosophy. Salient features of two candidates are presented that impose constraints on data management design. The second issue is the role of data management in terms of system integration. This referes to providing shared or coordinated data processing and storage resources to a variety of telerobotic components such as vision, mechanical sensing, real-time coordinated multiple limb and end effector control, and planning and reasoning. The third issue is hardware that supports symbolic processing in conjunction with standard data I/O and numeric processing. A SSP that currently is seen to be technologically feasible and is being developed is described and used as a baseline in the design concept.

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

Edwards, Harold C.; Ibanez, Daniel Alejandro

This report documents the ASC/ATDM Kokkos deliverable "Production Portable Dy- namic Task DAG Capability." This capability enables applications to create and execute a dynamic task DAG ; a collection of heterogeneous computational tasks with a directed acyclic graph (DAG) of "execute after" dependencies where tasks and their dependencies are dynamically created and destroyed as tasks execute. The Kokkos task scheduler executes the dynamic task DAG on the target execution resource; e.g. a multicore CPU, a manycore CPU such as Intel's Knights Landing (KNL), or an NVIDIA GPU. Several major technical challenges had to be addressed during development of Kokkos' Taskmore » DAG capability: (1) portability to a GPU with it's simplified hardware and micro- runtime, (2) thread-scalable memory allocation and deallocation from a bounded pool of memory, (3) thread-scalable scheduler for dynamic task DAG, (4) usability by applications.« less

The JPL/KSC telerobotic inspection demonstration

NASA Technical Reports Server (NTRS)

Mittman, David; Bon, Bruce; Collins, Carol; Fleischer, Gerry; Litwin, Todd; Morrison, Jack; Omeara, Jacquie; Peters, Stephen; Brogdon, John; Humeniuk, Bob

1990-01-01

An ASEA IRB90 robotic manipulator with attached inspection cameras was moved through a Space Shuttle Payload Assist Module (PAM) Cradle under computer control. The Operator and Operator Control Station, including graphics simulation, gross-motion spatial planning, and machine vision processing, were located at JPL. The Safety and Support personnel, PAM Cradle, IRB90, and image acquisition system, were stationed at the Kennedy Space Center (KSC). Images captured at KSC were used both for processing by a machine vision system at JPL, and for inspection by the JPL Operator. The system found collision-free paths through the PAM Cradle, demonstrated accurate knowledge of the location of both objects of interest and obstacles, and operated with a communication delay of two seconds. Safe operation of the IRB90 near Shuttle flight hardware was obtained both through the use of a gross-motion spatial planner developed at JPL using artificial intelligence techniques, and infrared beams and pressure sensitive strips mounted to the critical surfaces of the flight hardward at KSC. The Demonstration showed that telerobotics is effective for real tasks, safe for personnel and hardware, and highly productive and reliable for Shuttle payload operations and Space Station external operations.

Demonstration of a High-Fidelity Predictive/Preview Display Technique for Telerobotic Servicing in Space

NASA Technical Reports Server (NTRS)

Kim, Won S.; Bejczy, Antal K.

1993-01-01

A highly effective predictive/preview display technique for telerobotic servicing in space under several seconds communication time delay has been demonstrated on a large laboratory scale in May 1993, involving the Jet Propulsion Laboratory as the simulated ground control station and, 2500 miles away, the Goddard Space Flight Center as the simulated satellite servicing set-up. The technique is based on a high-fidelity calibration procedure that enables a high-fidelity overlay of 3-D graphics robot arm and object models over given 2-D TV camera images of robot arm and objects. To generate robot arm motions, the operator can confidently interact in real time with the graphics models of the robot arm and objects overlaid on an actual camera view of the remote work site. The technique also enables the operator to generate high-fidelity synthetic TV camera views showing motion events that are hidden in a given TV camera view or for which no TV camera views are available. The positioning accuracy achieved by this technique for a zoomed-in camera setting was about +/-5 mm, well within the allowable +/-12 mm error margin at the insertion of a 45 cm long tool in the servicing task.

Real-time hierarchically distributed processing network interaction simulation

NASA Technical Reports Server (NTRS)

Zimmerman, W. F.; Wu, C.

1987-01-01

The Telerobot Testbed is a hierarchically distributed processing system which is linked together through a standard, commercial Ethernet. Standard Ethernet systems are primarily designed to manage non-real-time information transfer. Therefore, collisions on the net (i.e., two or more sources attempting to send data at the same time) are managed by randomly rescheduling one of the sources to retransmit at a later time interval. Although acceptable for transmitting noncritical data such as mail, this particular feature is unacceptable for real-time hierarchical command and control systems such as the Telerobot. Data transfer and scheduling simulations, such as token ring, offer solutions to collision management, but do not appropriately characterize real-time data transfer/interactions for robotic systems. Therefore, models like these do not provide a viable simulation environment for understanding real-time network loading. A real-time network loading model is being developed which allows processor-to-processor interactions to be simulated, collisions (and respective probabilities) to be logged, collision-prone areas to be identified, and network control variable adjustments to be reentered as a means of examining and reducing collision-prone regimes that occur in the process of simulating a complete task sequence.

Telerobotic on-orbit remote fluid resupply system

NASA Technical Reports Server (NTRS)

1990-01-01

The development of a telerobotic on-orbit fluid resupply demonstration system is described. A fluid transfer demonstration system was developed which functionally simulates operations required to remotely transfer fluids (liquids or gases) from a servicing spacecraft to a receiving spacecraft through the use of telerobotic manipulations. The fluid system is representative of systems used by current or planned spacecraft and propulsion stages requiring on-orbit remote resupply. The system was integrated with an existing MSFC remotely controlled manipulator arm to mate/demate couplings for demonstration and evaluation of a complete remotely operated fluid transfer system.

The cooking task: making a meal of executive functions

PubMed Central

Doherty, T. A.; Barker, L. A.; Denniss, R.; Jalil, A.; Beer, M. D.

2015-01-01

Current standardized neuropsychological tests may fail to accurately capture real-world executive deficits. We developed a computer-based Cooking Task (CT) assessment of executive functions and trialed the measure with a normative group before use with a head-injured population. Forty-six participants completed the computerized CT and subtests from standardized neuropsychological tasks, including the Tower and Sorting Tests of executive function from the Delis-Kaplan Executive Function System (D-KEFS) and the Cambridge prospective memory test (CAMPROMPT), in order to examine whether standardized executive function tasks, predicted performance on measurement indices from the CT. Findings showed that verbal comprehension, rule detection and prospective memory contributed to measures of prospective planning accuracy and strategy implementation of the CT. Results also showed that functions necessary for cooking efficacy differ as an effect of task demands (difficulty levels). Performance on rule detection, strategy implementation and flexible thinking executive function measures contributed to accuracy on the CT. These findings raise questions about the functions captured by present standardized tasks particularly at varying levels of difficulty and during dual-task performance. Our preliminary findings also indicate that CT measures can effectively distinguish between executive function and Full Scale IQ abilities. Results of the present study indicate that the CT shows promise as an ecologically valid measure of executive function for future use with a head-injured population and indexes selective executive function’s captured by standardized tests. PMID:25717294

The cooking task: making a meal of executive functions.

PubMed

Doherty, T A; Barker, L A; Denniss, R; Jalil, A; Beer, M D

2015-01-01

Current standardized neuropsychological tests may fail to accurately capture real-world executive deficits. We developed a computer-based Cooking Task (CT) assessment of executive functions and trialed the measure with a normative group before use with a head-injured population. Forty-six participants completed the computerized CT and subtests from standardized neuropsychological tasks, including the Tower and Sorting Tests of executive function from the Delis-Kaplan Executive Function System (D-KEFS) and the Cambridge prospective memory test (CAMPROMPT), in order to examine whether standardized executive function tasks, predicted performance on measurement indices from the CT. Findings showed that verbal comprehension, rule detection and prospective memory contributed to measures of prospective planning accuracy and strategy implementation of the CT. Results also showed that functions necessary for cooking efficacy differ as an effect of task demands (difficulty levels). Performance on rule detection, strategy implementation and flexible thinking executive function measures contributed to accuracy on the CT. These findings raise questions about the functions captured by present standardized tasks particularly at varying levels of difficulty and during dual-task performance. Our preliminary findings also indicate that CT measures can effectively distinguish between executive function and Full Scale IQ abilities. Results of the present study indicate that the CT shows promise as an ecologically valid measure of executive function for future use with a head-injured population and indexes selective executive function's captured by standardized tests.

Teleoperated position control of a PUMA robot

NASA Technical Reports Server (NTRS)

Austin, Edmund; Fong, Chung P.

1987-01-01

A laboratory distributed computer control teleoperator system is developed to support NASA's future space telerobotic operation. This teleoperator system uses a universal force-reflecting hand controller in the local iste as the operator's input device. In the remote site, a PUMA controller recieves the Cartesian position commands and implements PID control laws to position the PUMA robot. The local site uses two microprocessors while the remote site uses three. The processors communicate with each other through shared memory. The PUMA robot controller was interfaced through custom made electronics to bypass VAL. The development status of this teleoperator system is reported. The execution time of each processor is analyzed, and the overall system throughput rate is reported. Methods to improve the efficiency and performance are discussed.

The role of telementoring and telerobotic assistance in the provision of laparoscopic colorectal surgery in rural areas.

PubMed

Sebajang, H; Trudeau, P; Dougall, A; Hegge, S; McKinley, C; Anvari, M

2006-09-01

The aim of this study was to assess whether telementoring and telerobotic assistance would improve the range and quality of laparoscopic colorectal surgery being performed by community surgeons. We present a series of 18 patients who underwent telementored or telerobotically assisted laparoscopic colorectal surgery in two community hospitals between December 2002 and December 2003. Four community surgeons with no formal advanced laparoscopic fellowship were remotely mentored and assisted by an expert surgeon from a tertiary care center. Telementoring was achieved with real-time two-way audio-video communications over bandwidths of 384 kbps-1.2 mbps and included one redo ileocolic resection, two right hemicolectomies, two sigmoid resections, three low anterior resections, one subtotal colectomy, one reversal of a Hartmann operation, and one abdominoperineal resection. A Zeus TS microjoint system (Computer Motion Inc, Santa Barbara CA) was used to provide telepresence for the telerobotically assisted laparoscopic procedures, which included three right hemicolectomies, three sigmoid resections, and one low anterior resection. There were no major intraoperative complications. There were two minor intraoperative complications involving serosal tears of the colon from the robotic graspers. In the telementored cases, there were two postoperative complications requiring reoperation (intra-abdominal bleeding and small bowel obstruction). Two telementored procedures were converted because of the mentee's inability to find the appropriate planes of dissection. One telerobotically assisted procedure was completed laparoscopically by the local surgeon with aid of telementoring because of inadequate robotic arm position. The median length of hospital stay for this series was 4 days. The surgeons considered telementoring useful in all cases (median score 4 out of 5). The use of remote telerobotic assistance was also considered a significant enabling tool. Telementoring and remote telerobotic assistance are excellent tools for supporting community surgeons and providing patients better access to advanced surgical care.

Proceedings of the NASA Conference on Space Telerobotics, volume 1

NASA Technical Reports Server (NTRS)

Rodriguez, Guillermo (Editor); Seraji, Homayoun (Editor)

1989-01-01

The theme of the Conference was man-machine collaboration in space. Topics addressed include: redundant manipulators; man-machine systems; telerobot architecture; remote sensing and planning; navigation; neural networks; fundamental AI research; and reasoning under uncertainty.

Application of structured analysis to a telerobotic system

NASA Technical Reports Server (NTRS)

Dashman, Eric; Mclin, David; Harrison, F. W.; Soloway, Donald; Young, Steven

1990-01-01

The analysis and evaluation of a multiple arm telerobotic research and demonstration system developed by the NASA Intelligent Systems Research Laboratory (ISRL) is described. Structured analysis techniques were used to develop a detailed requirements model of an existing telerobotic testbed. Performance models generated during this process were used to further evaluate the total system. A commercial CASE tool called Teamwork was used to carry out the structured analysis and development of the functional requirements model. A structured analysis and design process using the ISRL telerobotic system as a model is described. Evaluation of this system focused on the identification of bottlenecks in this implementation. The results demonstrate that the use of structured methods and analysis tools can give useful performance information early in a design cycle. This information can be used to ensure that the proposed system meets its design requirements before it is built.

Age-Related Differences in the Reliance on Executive Control in Working Memory: Role of Task Demand

PubMed Central

Isingrini, Michel; Angel, Lucie; Fay, Séverine; Taconnat, Laurence; Lemaire, Patrick; Bouazzaoui, Badiâa

2015-01-01

We examined the hypothesis that age-related differences in the reliance on executive control may be better explained by variations of task demand than by a mechanism specifically linked to aging. To this end, we compared the relationship between the performance of young and older adults on two executive functioning tests and an updating working-memory task with different load levels. The results revealed a significant interaction between age, task demand, and individual executive capacities, indicating that executive resources were only involved at lower loads in older adults, and only at higher loads in young adults. Overall, the results are not consistent with the proposition that cognition places greater demand on executive control in older adults. However, they support the view that how much young and older adults rely on executive control to accomplish cognitive tasks depends on task demand. Finally, interestingly these results are consistent with the CRUNCH model accounting for age-related differences in brain activations. PMID:26700019

Differential recruitment of executive resources during mind wandering.

PubMed

Kam, Julia W Y; Handy, Todd C

2014-05-01

Recent research has shown that mind wandering recruits executive resources away from the external task towards inner thoughts. No studies however have determined whether executive functions are drawn away in a unitary manner during mind wandering episodes, or whether there is variation in specific functions impacted. Accordingly, we examined whether mind wandering differentially modulates three core executive functions-response inhibition, updating of working memory, and mental set shifting. In three experiments, participants performed one of these three executive function tasks and reported their attentional state as either on-task or mind wandering at random intervals. We found that mind wandering led to poorer performance in the response inhibition and working memory tasks, but not the set-shifting task. These findings suggest that mind wandering does not recruit executive functions in a monolithic manner. Rather, it appears to selectively engage certain executive functions, which may reflect the adaptive maintenance of ongoing task performance. Copyright © 2014 Elsevier Inc. All rights reserved.

Age-Related Differences in the Reliance on Executive Control in Working Memory: Role of Task Demand.

PubMed

Isingrini, Michel; Angel, Lucie; Fay, Séverine; Taconnat, Laurence; Lemaire, Patrick; Bouazzaoui, Badiâa

2015-01-01

We examined the hypothesis that age-related differences in the reliance on executive control may be better explained by variations of task demand than by a mechanism specifically linked to aging. To this end, we compared the relationship between the performance of young and older adults on two executive functioning tests and an updating working-memory task with different load levels. The results revealed a significant interaction between age, task demand, and individual executive capacities, indicating that executive resources were only involved at lower loads in older adults, and only at higher loads in young adults. Overall, the results are not consistent with the proposition that cognition places greater demand on executive control in older adults. However, they support the view that how much young and older adults rely on executive control to accomplish cognitive tasks depends on task demand. Finally, interestingly these results are consistent with the CRUNCH model accounting for age-related differences in brain activations.

Executive functioning as a predictor of children's mathematics ability: inhibition, switching, and working memory.

PubMed

Bull, R; Scerif, G

2001-01-01

Children's mathematical skills were considered in relation to executive functions. Using multiple measures--including the Wisconsin Card Sorting Task (WCST), dual-task performance, Stroop task, and counting span-it was found that mathematical ability was significantly correlated with all measures of executive functioning, with the exception of dual-task performance. Furthermore, regression analyses revealed that each executive function measure predicted unique variance in mathematics ability. These results are discussed in terms of a central executive with diverse functions (Shallice & Burgess, 1996) and with recent evidence from Miyake, et al. (2000) showing the unity and diversity among executive functions. It is proposed that the particular difficulties for children of lower mathematical ability are lack of inhibition and poor working memory, which result in problems with switching and evaluation of new strategies for dealing with a particular task. The practical and theoretical implications of these results are discussed, along with suggestions for task changes and longitudinal studies that would clarify theoretical and developmental issues related to executive functioning.

Baseline tests of an autonomous telerobotic system for assembly of space truss structures

NASA Technical Reports Server (NTRS)

Rhodes, Marvin D.; Will, Ralph W.; Quach, Coung

1994-01-01

Several proposed space missions include precision reflectors that are larger in diameter than any current or proposed launch vehicle. Most of these reflectors will require a truss structure to accurately position the reflector panels and these reflectors will likely require assembly in orbit. A research program has been conducted at the NASA Langley Research Center to develop the technology required for the robotic assembly of truss structures. The focus of this research has been on hardware concepts, computer software control systems, and operator interfaces necessary to perform supervised autonomous assembly. A special facility was developed and four assembly and disassembly tests of a 102-strut tetrahedral truss have been conducted. The test procedures were developed around traditional 'pick-and-place' robotic techniques that rely on positioning repeatability for successful operation. The data from two of the four tests were evaluated and are presented in this report. All operations in the tests were controlled by predefined sequences stored in a command file, and the operator intervened only when the system paused because of the failure of an actuator command. The tests were successful in identifying potential pitfalls in a telerobotic system, many of which would not have been readily anticipated or incurred through simulation studies. Addressing the total integrated task, instead of bench testing the component parts, forced all aspects of the task to be evaluated. Although the test results indicate that additional developments should be pursued, no problems were encountered that would preclude automated assembly in space as a viable construction method.

Maximizing Total QoS-Provisioning of Image Streams with Limited Energy Budget

NASA Astrophysics Data System (ADS)

Lee, Wan Yeon; Kim, Kyong Hoon; Ko, Young Woong

To fully utilize the limited battery energy of mobile electronic devices, we propose an adaptive adjustment method of processing quality for multiple image stream tasks running with widely varying execution times. This adjustment method completes the worst-case executions of the tasks with a given budget of energy, and maximizes the total reward value of processing quality obtained during their executions by exploiting the probability distribution of task execution times. The proposed method derives the maximum reward value for the tasks being executable with arbitrary processing quality, and near maximum value for the tasks being executable with a finite number of processing qualities. Our evaluation on a prototype system shows that the proposed method achieves larger reward values, by up to 57%, than the previous method.

Human Mars Surface Science Operations

NASA Technical Reports Server (NTRS)

Bobskill, Marianne R.; Lupisella, Mark L.

2014-01-01

Human missions to the surface of Mars will have challenging science operations. This paper will explore some of those challenges, based on science operations considerations as part of more general operational concepts being developed by NASA's Human Spaceflight Architecture (HAT) Mars Destination Operations Team (DOT). The HAT Mars DOT has been developing comprehensive surface operations concepts with an initial emphasis on a multi-phased mission that includes a 500-day surface stay. This paper will address crew science activities, operational details and potential architectural and system implications in the areas of (a) traverse planning and execution, (b) sample acquisition and sample handling, (c) in-situ science analysis, and (d) planetary protection. Three cross-cutting themes will also be explored in this paper: (a) contamination control, (b) low-latency telerobotic science, and (c) crew autonomy. The present traverses under consideration are based on the report, Planning for the Scientific Exploration of Mars by Humans1, by the Mars Exploration Planning and Analysis Group (MEPAG) Human Exploration of Mars-Science Analysis Group (HEM-SAG). The traverses are ambitious and the role of science in those traverses is a key component that will be discussed in this paper. The process of obtaining, handling, and analyzing samples will be an important part of ensuring acceptable science return. Meeting planetary protection protocols will be a key challenge and this paper will explore operational strategies and system designs to meet the challenges of planetary protection, particularly with respect to the exploration of "special regions." A significant challenge for Mars surface science operations with crew is preserving science sample integrity in what will likely be an uncertain environment. Crewed mission surface assets -- such as habitats, spacesuits, and pressurized rovers -- could be a significant source of contamination due to venting, out-gassing and cleanliness levels associated with crew presence. Low-latency telerobotic science operations has the potential to address a number of contamination control and planetary protection issues and will be explored in this paper. Crew autonomy is another key cross-cutting challenge regarding Mars surface science operations, because the communications delay between earth and Mars could as high as 20 minutes one way, likely requiring the crew to perform many science tasks without direct timely intervention from ground support on earth. Striking the operational balance between crew autonomy and earth support will be a key challenge that this paper will address.

VR Simulation Testbed: Improving Surface Telerobotics for the Deep Space Gateway

NASA Astrophysics Data System (ADS)

Walker, M. E.; Burns, J. O.; Szafir, D. J.

2018-02-01

Design of a virtual reality simulation testbed for prototyping surface telerobotics. The goal is to create a framework with robust physics and kinematics to allow simulated teleoperation and supervised control of lunar rovers and rapid UI prototyping.

A collision detection algorithm for telerobotic arms

NASA Technical Reports Server (NTRS)

Tran, Doan Minh; Bartholomew, Maureen Obrien

1991-01-01

The telerobotic manipulator's collision detection algorithm is described. Its applied structural model of the world environment and template representation of objects is evaluated. Functional issues that are required for the manipulator to operate in a more complex and realistic environment are discussed.

Proceedings of the NASA Conference on Space Telerobotics, volume 3

NASA Technical Reports Server (NTRS)

Rodriguez, Guillermo (Editor); Seraji, Homayoun (Editor)

1989-01-01

The theme of the Conference was man-machine collaboration in space. The Conference provided a forum for researchers and engineers to exchange ideas on the research and development required for application of telerobotics technology to the space systems planned for the 1990s and beyond. The Conference: (1) provided a view of current NASA telerobotic research and development; (2) stimulated technical exchange on man-machine systems, manipulator control, machine sensing, machine intelligence, concurrent computation, and system architectures; and (3) identified important unsolved problems of current interest which can be dealt with by future research.

Telerobotics for Human Exploration: Enhancing Crew Capabilities in Deep Space

NASA Technical Reports Server (NTRS)

Fong, Terrence

2013-01-01

Future space missions in Earth orbit, to the Moon, and to other distant destinations offer many new opportunities for exploration. But, astronaut time will always be limited and some work will not be feasible or efficient for humans to perform manually. Telerobots, however, can complement human explorers, performing work under remote control from Earth, orbit or nearby habitats. A central challenge, therefore, is to understand how humans and remotely operated robots can be jointly employed to maximize mission performance and success. This presentation provides an overview of the key issues with using telerobots for human exploration.

Custom electronic subsystems for the laboratory telerobotic manipulator

NASA Technical Reports Server (NTRS)

Glassell, R. L.; Butler, P. L.; Rowe, J. C.; Zimmermann, S. D.

1990-01-01

The National Aeronautics and Space Administration (NASA) Space Station Program presents new opportunities for the application of telerobotic and robotic systems. The Laboratory Telerobotic Manipulator (LTM) is a highly advanced 7 degrees-of-freedom (DOF) telerobotic/robotic manipulator. It was developed and built for the Automation Technology Branch at NASA's Langley Research Center (LaRC) for work in research and to demonstrate ground-based telerobotic manipulator system hardware and software systems for future NASA applications in the hazardous environment of space. The LTM manipulator uses an embedded wiring design with all electronics, motor power, and control and communication cables passing through the pitch-yaw differential joints. This design requires the number of cables passing through the pitch/yaw joint to be kept to a minimum. To eliminate the cables needed to carry each pitch-yaw joint's sensor data to the VME control computers, a custom-embedded electronics package for each manipulator joint was developed. The electronics package collects and sends the joint's sensor data to the VME control computers over a fiber optic cable. The electronics package consist of five individual subsystems: the VME Link Processor, the Joint Processor and the Joint Processor power supply in the joint module, the fiber optics communications system, and the electronics and motor power cabling.

Performing a secondary executive task with affective stimuli interferes with decision making under risk conditions.

PubMed

Gathmann, Bettina; Pawlikowski, Mirko; Schöler, Tobias; Brand, Matthias

2014-05-01

Previous studies demonstrated that executive functions are crucial for advantageous decision making under risk and that therefore decision making is disrupted when working memory capacity is demanded while working on a decision task. While some studies also showed that emotions can affect decision making under risk, it is unclear how affective processing and executive functions predict decision-making performance in interaction. The current experimental study used a between-subjects design to examine whether affective pictures (positive and negative pictures compared to neutral pictures), included in a parallel executive task (working memory 2-back task), have an impact on decision making under risk as assessed by the Game of Dice Task (GDT). Moreover, the performance GDT plus 2-back task was compared to the performance in the GDT without any additional task (GDT solely). The results show that the performance in the GDT differed between groups (positive, negative, neutral, and GDT solely). The groups with affective pictures, especially those with positive pictures in the 2-back task, showed more disadvantageous decisions in the GDT than the groups with neutral pictures and the group performing the GDT without any additional task. However, executive functions moderated the effect of the affective pictures. Regardless of affective influence, subjects with good executive functions performed advantageously in the GDT. These findings support the assumption that executive functions and emotional processing interact in predicting decision making under risk.

Telerobotic Tending of Space Based Plant Growth Chamber

NASA Technical Reports Server (NTRS)

Backes, P. G.; Long, M. K.; Das, H.

1994-01-01

The kinematic design of a telerobotic mechanism for tending a plant growth space science experiment chamber is described. Ground based control of tending mechanisms internal to space science experiments will allow ground based principal investigators to interact directly with their space science experiments.

Space robotics in the '90s

NASA Technical Reports Server (NTRS)

Ruoff, Carl F.

1989-01-01

The use of telerobots and rovers in space missions is examined. The functioning of the telerobots and rovers and their proposed applications are described. Research developments needed to design robots for specific environments and functions are described. Examples of NASA robotics projects are presented.

Resolving Task Rule Incongruence during Task Switching by Competitor Rule Suppression

ERIC Educational Resources Information Center

Meiran, Nachshon; Hsieh, Shulan; Dimov, Eduard

2010-01-01

Task switching requires maintaining readiness to execute any task of a given set of tasks. However, when tasks switch, the readiness to execute the now-irrelevant task generates interference, as seen in the task rule incongruence effect. Overcoming such interference requires fine-tuned inhibition that impairs task readiness only minimally. In an…

Executive Resources and Item-Context Binding: Exploring the Influence of Concurrent Inhibition, Updating, and Shifting Tasks on Context Memory

PubMed Central

Nieznański, Marek; Obidziński, Michał; Zyskowska, Emilia; Niedziałkowska, Daria

2015-01-01

Previous research has demonstrated that context memory performance decreases as a result of cognitive load. However, the role of specific executive resources availability has not been specified yet. In a dual-task experiment, participants performed three kinds of concurrent task engaging: inhibition, updating, or shifting operations. In comparison with a no-load single-task condition, a significant decrease in item and context memory was observed, regardless of the kind of executive task. When executive load conditions were compared with non-specific cognitive load conditions, a significant interference effect was observed in the case of the inhibition task. The inhibition process appears to be an aspect of executive control, which relies on the same resource as item-context binding does, especially when binding refers to associations retrieved from long-term memory. PMID:26435761

Robotics Algorithms Provide Nutritional Guidelines

NASA Technical Reports Server (NTRS)

2009-01-01

On July 5, 1997, a small robot emerged from its lander like an insect from an egg, crawling out onto the rocky surface of Mars. About the size of a child s wagon, NASA s Sojourner robot was the first successful rover mission to the Red Planet. For 83 sols (Martian days, typically about 40 minutes longer than Earth days), Sojourner - largely remote controlled by NASA operators on Earth - transmitted photos and data unlike any previously collected. Sojourner was perhaps the crowning achievement of the NASA Space Telerobotics Program, an Agency initiative designed to push the limits of robotics in space. Telerobotics - devices that merge the autonomy of robotics with the direct human control of teleoperators - was already a part of NASA s efforts; probes like the Viking landers that preceded Sojourner on Mars, for example, were telerobotic applications. The Space Telerobotics Program, a collaboration between Ames Research Center, Johnson Space Center, Jet Propulsion Laboratory (JPL), and multiple universities, focused on developing remote-controlled robotics for three main purposes: on-orbit assembly and servicing, science payload tending, and planetary surface robotics. The overarching goal was to create robots that could be guided to build structures in space, monitor scientific experiments, and, like Sojourner, scout distant planets in advance of human explorers. While telerobotics remains a significant aspect of NASA s efforts, as evidenced by the currently operating Spirit and Opportunity Mars rovers, the Hubble Space Telescope, and many others - the Space Telerobotics Program was dissolved and redistributed within the Agency the same year as Sojourner s success. The program produced a host of remarkable technologies and surprising inspirations, including one that is changing the way people eat

Water immersion decreases sympathetic skin response during color–word Stroop test

PubMed Central

Yamazaki, Yudai; Takahashi, Akari; Uetake, Yoshihito; Nakano, Saki; Iguchi, Kaho; Baba, Yasuhiro; Nara, Rio; Shimoyama, Yoshimitsu

2017-01-01

Water immersion alters the autonomic nervous system (ANS) response in humans. The effect of water immersion on executive function and ANS responses related to executive function tasks was unknown. Therefore, this study aimed to determine whether water immersion alters ANS response during executive tasks. Fourteen healthy participants performed color–word-matching Stroop tasks before and after non-immersion and water immersion intervention for 15 min in separate sessions. The Stroop task-related skin conductance response (SCR) was measured during every task. In addition, the skin conductance level (SCL) and electrocardiograph signals were measured over the course of the experimental procedure. The main findings of the present study were as follows: 1) water immersion decreased the executive task-related sympathetic nervous response, but did not affect executive function as evaluated by Stroop tasks, and 2) decreased SCL induced by water immersion was maintained for at least 15 min after water immersion. In conclusion, the present results suggest that water immersion decreases the sympathetic skin response during the color–word Stroop test without altering executive performance. PMID:28742137

Water immersion decreases sympathetic skin response during color-word Stroop test.

PubMed

Sato, Daisuke; Yamazaki, Yudai; Takahashi, Akari; Uetake, Yoshihito; Nakano, Saki; Iguchi, Kaho; Baba, Yasuhiro; Nara, Rio; Shimoyama, Yoshimitsu

2017-01-01

Water immersion alters the autonomic nervous system (ANS) response in humans. The effect of water immersion on executive function and ANS responses related to executive function tasks was unknown. Therefore, this study aimed to determine whether water immersion alters ANS response during executive tasks. Fourteen healthy participants performed color-word-matching Stroop tasks before and after non-immersion and water immersion intervention for 15 min in separate sessions. The Stroop task-related skin conductance response (SCR) was measured during every task. In addition, the skin conductance level (SCL) and electrocardiograph signals were measured over the course of the experimental procedure. The main findings of the present study were as follows: 1) water immersion decreased the executive task-related sympathetic nervous response, but did not affect executive function as evaluated by Stroop tasks, and 2) decreased SCL induced by water immersion was maintained for at least 15 min after water immersion. In conclusion, the present results suggest that water immersion decreases the sympathetic skin response during the color-word Stroop test without altering executive performance.

Executive functioning and processing speed in age-related differences in memory: contribution of a coding task.

PubMed

Baudouin, Alexia; Clarys, David; Vanneste, Sandrine; Isingrini, Michel

2009-12-01

The aim of the present study was to examine executive dysfunctioning and decreased processing speed as potential mediators of age-related differences in episodic memory. We compared the performances of young and elderly adults in a free-recall task. Participants were also given tests to measure executive functions and perceptual processing speed and a coding task (the Digit Symbol Substitution Test, DSST). More precisely, we tested the hypothesis that executive functions would mediate the age-related differences observed in the free-recall task better than perceptual speed. We also tested the assumption that a coding task, assumed to involve both executive processes and perceptual speed, would be the best mediator of age-related differences in memory. Findings first confirmed that the DSST combines executive processes and perceptual speed. Secondly, they showed that executive functions are a significant mediator of age-related differences in memory, and that DSST performance is the best predictor.

Circadian Rhythms in Executive Function during the Transition to Adolescence: The Effect of Synchrony between Chronotype and Time of Day

ERIC Educational Resources Information Center

Hahn, Constanze; Cowell, Jason M.; Wiprzycka, Ursula J.; Goldstein, David; Ralph, Martin; Hasher, Lynn; Zelazo, Philip David

2012-01-01

To explore the influence of circadian rhythms on executive function during early adolescence, we administered a battery of executive function measures (including a Go-Nogo task, the Iowa Gambling Task, a Self-ordered Pointing task, and an Intra/Extradimensional Shift task) to Morning-preference and Evening-preference participants (N = 80) between…

Low-Latency Telerobotic Sample Return and Biomolecular Sequencing for Deep Space Gateway

NASA Astrophysics Data System (ADS)

Lupisella, M.; Bleacher, J.; Lewis, R.; Dworkin, J.; Wright, M.; Burton, A.; Rubins, K.; Wallace, S.; Stahl, S.; John, K.; Archer, D.; Niles, P.; Regberg, A.; Smith, D.; Race, M.; Chiu, C.; Russell, J.; Rampe, E.; Bywaters, K.

2018-02-01

Low-latency telerobotics, crew-assisted sample return, and biomolecular sequencing can be used to acquire and analyze lunar farside and/or Apollo landing site samples. Sequencing can also be used to monitor and study Deep Space Gateway environment and crew health.

Lunar Sample Return Missions Using a Tele-Robotic Lander

NASA Astrophysics Data System (ADS)

Downes, H.; Crawford, I. A.; Alexander, L.

2018-02-01

Deep Space Gateway would allow tele-robotic landers and rovers to access regions of the Moon which have not been previously sampled. Scientific questions, e.g., the nature and duration of volcanic activity and the composition of the mantle/lower crust, could be addressed.

Test bed experiments for various telerobotic system characteristics and configurations

NASA Technical Reports Server (NTRS)

Duffie, Neil A.; Wiker, Steven F.; Zik, John J.

1990-01-01

Dexterous manipulation and grasping in telerobotic systems depends on the integration of high-performance sensors, displays, actuators and controls into systems in which careful consideration has been given to human perception and tolerance. Research underway at the Wisconsin Center for Space Automation and Robotics (WCSAR) has the objective of enhancing the performance of these systems and their components, and quantifying the effects of the many electrical, mechanical, control, and human factors that affect their performance. This will lead to a fundamental understanding of performance issues which will in turn allow designers to evaluate sensor, actuator, display, and control technologies with respect to generic measures of dexterous performance. As part of this effort, an experimental test bed was developed which has telerobotic components with exceptionally high fidelity in master/slave operation. A Telerobotic Performance Analysis System has also been developed which allows performance to be determined for various system configurations and electro-mechanical characteristics. Both this performance analysis system and test bed experiments are described.

Surface Telerobotics: Development and Testing of a Crew Controlled Planetary Rover System

NASA Technical Reports Server (NTRS)

Bualat, Maria G.; Fong, Terrence; Allan, Mark; Bouyssounouse, Xavier; Cohen, Tamar; Kobayashi, Linda

2013-01-01

In planning for future exploration missions, architecture and study teams have made numerous assumptions about how crew can be telepresent on a planetary surface by remotely operating surface robots from space (i.e. from a flight vehicle or deep space habitat). These assumptions include estimates of technology maturity, existing technology gaps, and operational risks. These assumptions, however, have not been grounded by experimental data. Moreover, to date, no crew-controlled surface telerobot has been fully tested in a high-fidelity manner. To address these issues, we developed the "Surface Telerobotics" tests to do three things: 1) Demonstrate interactive crew control of a mobile surface telerobot in the presence of short communications delay. 2) Characterize a concept of operations for a single astronaut remotely operating a planetary rover with limited support from ground control. 3) Characterize system utilization and operator work-load for a single astronaut remotely operating a planetary rover with limited support from ground control.

A universal computer control system for motors

NASA Technical Reports Server (NTRS)

Szakaly, Zoltan F. (Inventor)

1991-01-01

A control system for a multi-motor system such as a space telerobot, having a remote computational node and a local computational node interconnected with one another by a high speed data link is described. A Universal Computer Control System (UCCS) for the telerobot is located at each node. Each node is provided with a multibus computer system which is characterized by a plurality of processors with all processors being connected to a common bus, and including at least one command processor. The command processor communicates over the bus with a plurality of joint controller cards. A plurality of direct current torque motors, of the type used in telerobot joints and telerobot hand-held controllers, are connected to the controller cards and responds to digital control signals from the command processor. Essential motor operating parameters are sensed by analog sensing circuits and the sensed analog signals are converted to digital signals for storage at the controller cards where such signals can be read during an address read/write cycle of the command processing processor.

System architectures for telerobotic research

NASA Technical Reports Server (NTRS)

Harrison, F. Wallace

1989-01-01

Several activities are performed related to the definition and creation of telerobotic systems. The effort and investment required to create architectures for these complex systems can be enormous; however, the magnitude of process can be reduced if structured design techniques are applied. A number of informal methodologies supporting certain aspects of the design process are available. More recently, prototypes of integrated tools supporting all phases of system design from requirements analysis to code generation and hardware layout have begun to appear. Activities related to system architecture of telerobots are described, including current activities which are designed to provide a methodology for the comparison and quantitative analysis of alternative system architectures.

Design of a telerobotic controller with joint torque sensors

NASA Technical Reports Server (NTRS)

Jansen, J. F.; Herndon, J. N.

1990-01-01

The purpose was to analytically show how to design a joint controller for a telerobotic system when joint torque sensors are available. Other sensors such as actuator position, actuator velocity, joint position, and joint velocity are assumed to be accessible; however, the results will also be useful when only partial measurements are available. The controller presented can be applied to either mode of operation of a manipulator (i.e., teleoperation or robotic). Mechanical manipulators with high levels of friction are assumed. The results are applied to a telerobotic system built for NASA. Very high levels of friction have been reduced using high-gain feedback while avoiding limit cycles.

Acute effects of donepezil in healthy young adults underline the fractionation of executive functioning.

PubMed

Ginani, G E; Tufik, S; Bueno, O F A; Pradella-Hallinan, M; Rusted, J; Pompéia, S

2011-11-01

The cholinergic system is involved in the modulation of both bottom-up and top-down attentional control. Top-down attention engages multiple executive control processes, but few studies have investigated whether all or selective elements of executive functions are modulated by the cholinergic system. To investigate the acute effects of the pro-cholinergic donepezil in young, healthy volunteers on distinct components of executive functions we conducted a double-blind, placebo-controlled, independent-groups design study including 42 young healthy male participants who were randomly assigned to one of three oral treatments: glucose (placebo), donepezil 5 mg or donepezil 7.5 mg. The test battery included measures of different executive components (shifting, updating, inhibition, dual-task performance, planning, access to long-term memory), tasks that evaluated arousal/vigilance/visuomotor performance, as well as functioning of working memory subsidiary systems. Donepezil improved sustained attention, reaction times, dual-task performance and the executive component of digit span. The positive effects in these executive tasks did not correlate with arousal/visuomotor/vigilance measures. Among the various executive domains investigated donepezil selectively increased dual-task performance in a manner that could not be ascribed to improvement in arousal/vigilance/visuomotor performance nor working memory slave systems. Other executive tasks that rely heavily on visuospatial processing may also be modulated by the cholinergic system.

Relationships between executive function, working memory, and decision-making on the Iowa Gambling Task: Evidence from ventromedial patients, dorsolateral patients, and normal subjects.

PubMed

Ouerchefani, Riadh; Ouerchefani, Naoufel; Allain, Philippe; Ben Rejeb, Mohamed Riadh; Le Gall, Didier

2018-04-17

The results of previous studies are inconsistent in regard to the relationship between the Iowa Gambling Task (IGT), working-memory (WM), and executive tasks, and whether these cognitive processes could be considered as mechanisms underlying a decision-making deficit. Moreover, the relationship between the IGT and executive measures is examined based on a limited number of executive tasks, within different populations showing diffuse damage. In addition, there are fewer studies carried out within control participants, with those studies also being inconclusive. It is also suggested that the association of the IGT performance with executive tasks depends on whether the IGT was running under ambiguity or under risk. In this work, all of these issues are studied. Results showed that both patients with ventromedial (VMPFC, N = 10) and dorsolateral (DLPFC, N = 10) prefrontal cortex lesions are significantly impaired on almost all executive tasks, WM tasks, and the IGT. Furthermore, when the IGT is run under risk, there are significant correlations between executive measures and the IGT for the DLPFC patients and the control participants (N = 34) but not the VMPFC patients. No correlation was found between WM tasks and the IGT for both frontal subgroups and control participants. These findings suggested that the mechanisms underlying the IGT deficit differ according to the lesion locations. © 2018 The British Psychological Society.

Age-Related Differences in Multiple Task Monitoring

PubMed Central

Todorov, Ivo; Del Missier, Fabio; Mäntylä, Timo

2014-01-01

Coordinating multiple tasks with narrow deadlines is particularly challenging for older adults because of age related decline in cognitive control functions. We tested the hypothesis that multiple task performance reflects age- and gender-related differences in executive functioning and spatial ability. Young and older adults completed a multitasking session with four monitoring tasks as well as separate tasks measuring executive functioning and spatial ability. For both age groups, men exceeded women in multitasking, measured as monitoring accuracy. Individual differences in executive functioning and spatial ability were independent predictors of young adults' monitoring accuracy, but only spatial ability was related to sex differences. For older adults, age and executive functioning, but not spatial ability, predicted multitasking performance. These results suggest that executive functions contribute to multiple task performance across the adult life span and that reliance on spatial skills for coordinating deadlines is modulated by age. PMID:25215609

Age-related differences in multiple task monitoring.

PubMed

Todorov, Ivo; Del Missier, Fabio; Mäntylä, Timo

2014-01-01

Coordinating multiple tasks with narrow deadlines is particularly challenging for older adults because of age related decline in cognitive control functions. We tested the hypothesis that multiple task performance reflects age- and gender-related differences in executive functioning and spatial ability. Young and older adults completed a multitasking session with four monitoring tasks as well as separate tasks measuring executive functioning and spatial ability. For both age groups, men exceeded women in multitasking, measured as monitoring accuracy. Individual differences in executive functioning and spatial ability were independent predictors of young adults' monitoring accuracy, but only spatial ability was related to sex differences. For older adults, age and executive functioning, but not spatial ability, predicted multitasking performance. These results suggest that executive functions contribute to multiple task performance across the adult life span and that reliance on spatial skills for coordinating deadlines is modulated by age.

Design and implementation of visual-haptic assistive control system for virtual rehabilitation exercise and teleoperation manipulation.

PubMed

Veras, Eduardo J; De Laurentis, Kathryn J; Dubey, Rajiv

2008-01-01

This paper describes the design and implementation of a control system that integrates visual and haptic information to give assistive force feedback through a haptic controller (Omni Phantom) to the user. A sensor-based assistive function and velocity scaling program provides force feedback that helps the user complete trajectory following exercises for rehabilitation purposes. This system also incorporates a PUMA robot for teleoperation, which implements a camera and a laser range finder, controlled in real time by a PC, were implemented into the system to help the user to define the intended path to the selected target. The real-time force feedback from the remote robot to the haptic controller is made possible by using effective multithreading programming strategies in the control system design and by novel sensor integration. The sensor-based assistant function concept applied to teleoperation as well as shared control enhances the motion range and manipulation capabilities of the users executing rehabilitation exercises such as trajectory following along a sensor-based defined path. The system is modularly designed to allow for integration of different master devices and sensors. Furthermore, because this real-time system is versatile the haptic component can be used separately from the telerobotic component; in other words, one can use the haptic device for rehabilitation purposes for cases in which assistance is needed to perform tasks (e.g., stroke rehab) and also for teleoperation with force feedback and sensor assistance in either supervisory or automatic modes.

A run-time control architecture for the JPL telerobot

NASA Technical Reports Server (NTRS)

Balaram, J.; Lokshin, A.; Kreutz, K.; Beahan, J.

1987-01-01

An architecture for implementing the process-level decision making for a hierarchically structured telerobot currently being implemented at the Jet Propolusion Laboratory (JPL) is described. Constraints on the architecture design, architecture partitioning concepts, and a detailed description of the existing and proposed implementations are provided.

Estimation Accuracy on Execution Time of Run-Time Tasks in a Heterogeneous Distributed Environment.

PubMed

Liu, Qi; Cai, Weidong; Jin, Dandan; Shen, Jian; Fu, Zhangjie; Liu, Xiaodong; Linge, Nigel

2016-08-30

Distributed Computing has achieved tremendous development since cloud computing was proposed in 2006, and played a vital role promoting rapid growth of data collecting and analysis models, e.g., Internet of things, Cyber-Physical Systems, Big Data Analytics, etc. Hadoop has become a data convergence platform for sensor networks. As one of the core components, MapReduce facilitates allocating, processing and mining of collected large-scale data, where speculative execution strategies help solve straggler problems. However, there is still no efficient solution for accurate estimation on execution time of run-time tasks, which can affect task allocation and distribution in MapReduce. In this paper, task execution data have been collected and employed for the estimation. A two-phase regression (TPR) method is proposed to predict the finishing time of each task accurately. Detailed data of each task have drawn interests with detailed analysis report being made. According to the results, the prediction accuracy of concurrent tasks' execution time can be improved, in particular for some regular jobs.

Establishment of the world's first telerobotic remote surgical service: for provision of advanced laparoscopic surgery in a rural community.

PubMed

Anvari, Mehran; McKinley, Craig; Stein, Harvey

2005-03-01

To establish a telerobotic surgical service between a teaching hospital and a rural hospital for provision of telerobotic surgery and assistance to aid rural surgeons in providing a variety of advanced laparoscopic surgery to their community patients. The above service was established between St. Joseph's Hospital in Hamilton and North Bay General Hospital 400 km north of Hamilton on February 28, 2003. The service uses an IP-VPN (15 Mbps of bandwidth) commercially available network to connect the robotic console in Hamilton with 3 arms of the Zeus-TS surgical system in North Bay. To date, 21 telerobotic laparoscopic surgeries have taken place between North Bay and Hamilton, including 13 fundoplications, 3 sigmoid resections, 2 right hemicolectomies, 1 anterior resection, and 2 inguinal hernia repairs. The 2 surgeons were able to operate together using the same surgical footprint and interchange roles seamlessly when desired. There have been no serious intraoperative complications and no cases have had to be converted to open surgeries. The mean hospital stays were equivalent to mean laparoscopic LOS in the tertiary institution. Telerobotic remote surgery is now in routine use, providing high-quality laparoscopic surgical services to patients in a rural community and providing a superior degree of collaboration between surgeons in teaching hospitals and rural hospitals. Further refinement of the robotic and telecommunication technology should ensure its wider application in the near future.

Establishment of the World's First Telerobotic Remote Surgical Service

PubMed Central

Anvari, Mehran; McKinley, Craig; Stein, Harvey

2005-01-01

Objective: To establish a telerobotic surgical service between a teaching hospital and a rural hospital for provision of telerobotic surgery and assistance to aid rural surgeons in providing a variety of advanced laparoscopic surgery to their community patients. Summary Background Data: The above service was established between St. Joseph's Hospital in Hamilton and North Bay General Hospital 400 km north of Hamilton on February 28, 2003. The service uses an IP-VPN (15 Mbps of bandwidth) commercially available network to connect the robotic console in Hamilton with 3 arms of the Zeus-TS surgical system in North Bay. Results: To date, 21 telerobotic laparoscopic surgeries have taken place between North Bay and Hamilton, including 13 fundoplications, 3 sigmoid resections, 2 right hemicolectomies, 1 anterior resection, and 2 inguinal hernia repairs. The 2 surgeons were able to operate together using the same surgical footprint and interchange roles seamlessly when desired. There have been no serious intraoperative complications and no cases have had to be converted to open surgeries. The mean hospital stays were equivalent to mean laparoscopic LOS in the tertiary institution. Conclusions: Telerobotic remote surgery is now in routine use, providing high-quality laparoscopic surgical services to patients in a rural community and providing a superior degree of collaboration between surgeons in teaching hospitals and rural hospitals. Further refinement of the robotic and telecommunication technology should ensure its wider application in the near future. PMID:15729068

Component processes in voluntary task switching.

PubMed

Demanet, Jelle; Liefooghe, Baptist

2014-05-01

The present study investigated the involvement of bottom-up and top-down control in task-switching situations in which tasks are selected on a voluntary basis. We tested for indices of both types of control in the reduction in switch cost that is observed when more time is available before executing a task. Participants had to indicate their task choice overtly prior to the actual task execution, and two time intervals were manipulated: the interval between the task-execution response of the previous trial and task-indication response of the current trial and the interval between task-indication response and task-execution response of a particular trial. In Experiment 1, the length of these intervals was manipulated orthogonally, and indices for top-down and bottom-up control were observed. Concerned with the validity of these results, Experiments 2-3 additionally discouraged participants from preparing the upcoming task before their task-indication response. Indices for bottom-up control remained, but not for top-down control. The characteristics of top-down and bottom-up control in voluntary task switching and task switching in general are discussed.

NASA Virtual Glovebox (VBX): Emerging Simulation Technology for Space Station Experiment Design, Development, Training and Troubleshooting

NASA Technical Reports Server (NTRS)

Smith, Jeffrey D.; Twombly, I. Alexander; Maese, A. Christopher; Cagle, Yvonne; Boyle, Richard

2003-01-01

The International Space Station demonstrates the greatest capabilities of human ingenuity, international cooperation and technology development. The complexity of this space structure is unprecedented; and training astronaut crews to maintain all its systems, as well as perform a multitude of research experiments, requires the most advanced training tools and techniques. Computer simulation and virtual environments are currently used by astronauts to train for robotic arm manipulations and extravehicular activities; but now, with the latest computer technologies and recent successes in areas of medical simulation, the capability exists to train astronauts for more hands-on research tasks using immersive virtual environments. We have developed a new technology, the Virtual Glovebox (VGX), for simulation of experimental tasks that astronauts will perform aboard the Space Station. The VGX may also be used by crew support teams for design of experiments, testing equipment integration capability and optimizing the procedures astronauts will use. This is done through the 3D, desk-top sized, reach-in virtual environment that can simulate the microgravity environment in space. Additional features of the VGX allow for networking multiple users over the internet and operation of tele-robotic devices through an intuitive user interface. Although the system was developed for astronaut training and assisting support crews, Earth-bound applications, many emphasizing homeland security, have also been identified. Examples include training experts to handle hazardous biological and/or chemical agents in a safe simulation, operation of tele-robotic systems for assessing and diffusing threats such as bombs, and providing remote medical assistance to field personnel through a collaborative virtual environment. Thus, the emerging VGX simulation technology, while developed for space- based applications, can serve a dual use facilitating homeland security here on Earth.

Head-controlled assistive telerobot with extended physiological proprioception capability

NASA Astrophysics Data System (ADS)

Salganicoff, Marcos; Rahman, Tariq; Mahoney, Ricardo; Pino, D.; Jayachandran, Vijay; Kumar, Vijay; Chen, Shoupu; Harwin, William S.

1995-12-01

People with disabilities such as quadriplegia can use mouth-sticks and head-sticks as extension devices to perform desired manipulations. These extensions provide extended proprioception which allows users to directly feel forces and other perceptual cues such as texture present at the tip of the mouth-stick. Such devices are effective for two principle reasons: because of their close contact with the user's tactile and proprioceptive sensing abilities; and because they tend to be lightweight and very stiff, and can thus convey tactile and kinesthetic information with high-bandwidth. Unfortunately, traditional mouth-sticks and head-sticks are limited in workspace and in the mechanical power that can be transferred because of user mobility and strength limitations. We describe an alternative implementation of the head-stick device using the idea of a virtual head-stick: a head-controlled bilateral force-reflecting telerobot. In this system the end-effector of the slave robot moves as if it were at the tip of an imaginary extension of the user's head. The design goal is for the system is to have the same intuitive operation and extended proprioception as a regular mouth-stick effector but with augmentation of workspace volume and mechanical power. The input is through a specially modified six DOF master robot (a PerForceTM hand-controller) whose joints can be back-driven to apply forces at the user's head. The manipulation tasks in the environment are performed by a six degree-of-freedom slave robot (the Zebra-ZEROTM) with a built-in force sensor. We describe the prototype hardware/software implementation of the system, control system design, safety/disability issues, and initial evaluation tasks.

Man-machine cooperation in advanced teleoperation

NASA Technical Reports Server (NTRS)

Fiorini, Paolo; Das, Hari; Lee, Sukhan

1993-01-01

Teleoperation experiments at JPL have shown that advanced features in a telerobotic system are a necessary condition for good results, but that they are not sufficient to assure consistently good performance by the operators. Two or three operators are normally used during training and experiments to maintain the desired performance. An alternative to this multi-operator control station is a man-machine interface embedding computer programs that can perform some of the operator's functions. In this paper we present our first experiments with these concepts, in which we focused on the areas of real-time task monitoring and interactive path planning. In the first case, when performing a known task, the operator has an automatic aid for setting control parameters and camera views. In the second case, an interactive path planner will rank different path alternatives so that the operator will make the correct control decision. The monitoring function has been implemented with a neural network doing the real-time task segmentation. The interactive path planner was implemented for redundant manipulators to specify arm configurations across the desired path and satisfy geometric, task, and performance constraints.

Differential Contribution of Bilateral Supplementary Motor Area to the Effective Connectivity Networks Induced by Task Conditions Using Dynamic Causal Modeling

PubMed Central

Tao, Zhongping; Zhang, Mu

2014-01-01

Abstract Functional imaging studies have indicated hemispheric asymmetry of activation in bilateral supplementary motor area (SMA) during unimanual motor tasks. However, the hemispherically special roles of bilateral SMAs on primary motor cortex (M1) in the effective connectivity networks (ECN) during lateralized tasks remain unclear. Aiming to study the differential contribution of bilateral SMAs during the motor execution and motor imagery tasks, and the hemispherically asymmetric patterns of ECN among regions involved, the present study used dynamic causal modeling to analyze the functional magnetic resonance imaging data of the unimanual motor execution/imagery tasks in 12 right-handed subjects. Our results demonstrated that distributions of network parameters underlying motor execution and motor imagery were significantly different. The variation was mainly induced by task condition modulations of intrinsic coupling. Particularly, regardless of the performing hand, the task input modulations of intrinsic coupling from the contralateral SMA to contralateral M1 were positive during motor execution, while varied to be negative during motor imagery. The results suggested that the inhibitive modulation suppressed the overt movement during motor imagery. In addition, the left SMA also helped accomplishing left hand tasks through task input modulation of left SMA→right SMA connection, implying that hemispheric recruitment occurred when performing nondominant hand tasks. The results specified differential and altered contributions of bilateral SMAs to the ECN during unimanual motor execution and motor imagery, and highlighted the contributions induced by the task input of motor execution/imagery. PMID:24606178

An Intelligent Simulator for Telerobotics Training

ERIC Educational Resources Information Center

Belghith, K.; Nkambou, R.; Kabanza, F.; Hartman, L.

2012-01-01

Roman Tutor is a tutoring system that uses sophisticated domain knowledge to monitor the progress of students and advise them while they are learning how to operate a space telerobotic system. It is intended to help train operators of the Space Station Remote Manipulator System (SSRMS) including astronauts, operators involved in ground-based…

Executive Control in a Modified Antisaccade Task: Effects of Aging and Bilingualism

ERIC Educational Resources Information Center

Bialystok, Ellen; Craik, Fergus I. M.; Ryan, Jennifer

2006-01-01

Two studies are reported that assess differences associated with aging and bilingualism in an executive control task. Previous work has suggested that bilinguals have an advantage over monolinguals in nonlinguistic tasks involving executive control; the major purpose of the present article is to ascertain which aspects of control are sensitive…

Grid workflow job execution service 'Pilot'

NASA Astrophysics Data System (ADS)

Shamardin, Lev; Kryukov, Alexander; Demichev, Andrey; Ilyin, Vyacheslav

2011-12-01

'Pilot' is a grid job execution service for workflow jobs. The main goal for the service is to automate computations with multiple stages since they can be expressed as simple workflows. Each job is a directed acyclic graph of tasks and each task is an execution of something on a grid resource (or 'computing element'). Tasks may be submitted to any WS-GRAM (Globus Toolkit 4) service. The target resources for the tasks execution are selected by the Pilot service from the set of available resources which match the specific requirements from the task and/or job definition. Some simple conditional execution logic is also provided. The 'Pilot' service is built on the REST concepts and provides a simple API through authenticated HTTPS. This service is deployed and used in production in a Russian national grid project GridNNN.

[Working memory and executive control: inhibitory processes in updating and random generation tasks].

PubMed

Macizo, Pedro; Bajo, Teresa; Soriano, Maria Felipa

2006-02-01

Working Memory (WM) span predicts subjects' performance in control executive tasks and, in addition, it has been related to the capacity to inhibit irrelevant information. In this paper we investigate the role of WM span in two executive tasks focusing our attention on inhibitory components of both tasks. High and low span participants recalled targets words rejecting irrelevant items at the same time (Experiment 1) and they generated random numbers (Experiment 2). Results showed a clear relation between WM span and performance in both tasks. In addition, analyses of intrusion errors (Experiment 1) and stereotyped responses (Experiment 2) indicated that high span individuals were able to efficiently use the inhibitory component implied in both tasks. The pattern of data provides support to the relation between WM span and control executive tasks through an inhibitory mechanism.

Checkpointing for a hybrid computing node

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

Cher, Chen-Yong

2016-03-08

According to an aspect, a method for checkpointing in a hybrid computing node includes executing a task in a processing accelerator of the hybrid computing node. A checkpoint is created in a local memory of the processing accelerator. The checkpoint includes state data to restart execution of the task in the processing accelerator upon a restart operation. Execution of the task is resumed in the processing accelerator after creating the checkpoint. The state data of the checkpoint are transferred from the processing accelerator to a main processor of the hybrid computing node while the processing accelerator is executing the task.

Compliant Task Execution and Learning for Safe Mixed-Initiative Human-Robot Operations

NASA Technical Reports Server (NTRS)

Dong, Shuonan; Conrad, Patrick R.; Shah, Julie A.; Williams, Brian C.; Mittman, David S.; Ingham, Michel D.; Verma, Vandana

2011-01-01

We introduce a novel task execution capability that enhances the ability of in-situ crew members to function independently from Earth by enabling safe and efficient interaction with automated systems. This task execution capability provides the ability to (1) map goal-directed commands from humans into safe, compliant, automated actions, (2) quickly and safely respond to human commands and actions during task execution, and (3) specify complex motions through teaching by demonstration. Our results are applicable to future surface robotic systems, and we have demonstrated these capabilities on JPL's All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE) robot.

Language and Memory Improvements following tDCS of Left Lateral Prefrontal Cortex.

PubMed

Hussey, Erika K; Ward, Nathan; Christianson, Kiel; Kramer, Arthur F

2015-01-01

Recent research demonstrates that performance on executive-control measures can be enhanced through brain stimulation of lateral prefrontal regions. Separate psycholinguistic work emphasizes the importance of left lateral prefrontal cortex executive-control resources during sentence processing, especially when readers must override early, incorrect interpretations when faced with temporary ambiguity. Using transcranial direct current stimulation, we tested whether stimulation of left lateral prefrontal cortex had discriminate effects on language and memory conditions that rely on executive-control (versus cases with minimal executive-control demands, even in the face of task difficulty). Participants were randomly assigned to receive Anodal, Cathodal, or Sham stimulation of left lateral prefrontal cortex while they (1) processed ambiguous and unambiguous sentences in a word-by-word self-paced reading task and (2) performed an n-back memory task that, on some trials, contained interference lure items reputed to require executive-control. Across both tasks, we parametrically manipulated executive-control demands and task difficulty. Our results revealed that the Anodal group outperformed the remaining groups on (1) the sentence processing conditions requiring executive-control, and (2) only the most complex n-back conditions, regardless of executive-control demands. Together, these findings add to the mounting evidence for the selective causal role of left lateral prefrontal cortex for executive-control tasks in the language domain. Moreover, we provide the first evidence suggesting that brain stimulation is a promising method to mitigate processing demands encountered during online sentence processing.

Language and Memory Improvements following tDCS of Left Lateral Prefrontal Cortex

PubMed Central

Hussey, Erika K.; Ward, Nathan; Christianson, Kiel; Kramer, Arthur F.

2015-01-01

Recent research demonstrates that performance on executive-control measures can be enhanced through brain stimulation of lateral prefrontal regions. Separate psycholinguistic work emphasizes the importance of left lateral prefrontal cortex executive-control resources during sentence processing, especially when readers must override early, incorrect interpretations when faced with temporary ambiguity. Using transcranial direct current stimulation, we tested whether stimulation of left lateral prefrontal cortex had discriminate effects on language and memory conditions that rely on executive-control (versus cases with minimal executive-control demands, even in the face of task difficulty). Participants were randomly assigned to receive Anodal, Cathodal, or Sham stimulation of left lateral prefrontal cortex while they (1) processed ambiguous and unambiguous sentences in a word-by-word self-paced reading task and (2) performed an n-back memory task that, on some trials, contained interference lure items reputed to require executive-control. Across both tasks, we parametrically manipulated executive-control demands and task difficulty. Our results revealed that the Anodal group outperformed the remaining groups on (1) the sentence processing conditions requiring executive-control, and (2) only the most complex n-back conditions, regardless of executive-control demands. Together, these findings add to the mounting evidence for the selective causal role of left lateral prefrontal cortex for executive-control tasks in the language domain. Moreover, we provide the first evidence suggesting that brain stimulation is a promising method to mitigate processing demands encountered during online sentence processing. PMID:26528814

The telerobot testbed: An architecture for remote servicing

NASA Technical Reports Server (NTRS)

Matijevic, J. R.

1990-01-01

The NASA/OAST Telerobot Testbed will reach its next increment in development by the end of FY-89. The testbed will have the capability for: force reflection in teleoperation, shared control, traded control, operator designate and relative update. These five capabilities will be shown in a module release and exchange operation using mockups of Orbital Replacement Units (ORU). This development of the testbed shows examples of the technologies needed for remote servicing, particularly under conditions of delay in transmissions to the servicing site. Here, the following topics are presented: the system architecture of the testbed which incorporates these telerobotic technologies for servicing, the implementation of the five capabilities and the operation of the ORU mockups.

Time-on-task effects in children with and without ADHD: depletion of executive resources or depletion of motivation?

PubMed

Dekkers, Tycho J; Agelink van Rentergem, Joost A; Koole, Alette; van den Wildenberg, Wery P M; Popma, Arne; Bexkens, Anika; Stoffelsen, Reino; Diekmann, Anouk; Huizenga, Hilde M

2017-12-01

Children with attention-deficit/hyperactivity disorder (ADHD) are characterized by deficits in their executive functioning and motivation. In addition, these children are characterized by a decline in performance as time-on-task increases (i.e., time-on-task effects). However, it is unknown whether these time-on-task effects should be attributed to deficits in executive functioning or to deficits in motivation. Some studies in typically developing (TD) adults indicated that time-on-task effects should be interpreted as depletion of executive resources, but other studies suggested that they represent depletion of motivation. We, therefore, investigated, in children with and without ADHD, whether there were time-on-task effects on executive functions, such as inhibition and (in)attention, and whether these were best explained by depletion of executive resources or depletion of motivation. The stop-signal task (SST), which generates both indices of inhibition (stop-signal reaction time) and attention (reaction time variability and errors), was administered in 96 children (42 ADHD, 54 TD controls; aged 9-13). To differentiate between depletion of resources and depletion of motivation, the SST was administered twice. Half of the participants was reinforced during second task performance, potentially counteracting depletion of motivation. Multilevel analyses indicated that children with ADHD were more affected by time-on-task than controls on two measures of inattention, but not on inhibition. In the ADHD group, reinforcement only improved performance on one index of attention (i.e., reaction time variability). The current findings suggest that time-on-task effects in children with ADHD occur specifically in the attentional domain, and seem to originate in both depletion of executive resources and depletion of motivation. Clinical implications for diagnostics, psycho-education, and intervention are discussed.

A situated reasoning architecture for space-based repair and replace tasks

NASA Technical Reports Server (NTRS)

Bloom, Ben; Mcgrath, Debra; Sanborn, Jim

1989-01-01

Space-based robots need low level control for collision detection and avoidance, short-term load management, fine-grained motion, and other physical tasks. In addition, higher level control is required to focus strategic decision making as missions are assigned and carried out. Reasoning and control must be responsive to ongoing changes in the environment. Research aimed at bridging the gap between high level artificial intelligence (AI) planning techniques and task-level robot programming for telerobotic systems is described. Situated reasoning is incorporated into AI and Robotics systems in order to coordinate a robot's activity within its environment. An integrated system under development in a component maintenance domain is described. It is geared towards replacing worn and/or failed Orbital Replacement Units (ORUs) designed for use aboard NASA's Space Station Freedom based on the collection of components available at a given time. High level control reasons in component space in order to maximize the number operational component-cells over time, while the task-level controls sensors and effectors, detects collisions, and carries out pick and place tasks in physical space. Situated reasoning is used throughout the system to cope with component failures, imperfect information, and unexpected events.

Relating Self Reports of Writing Behaviour and Online Task Execution Using a Temporal Model

ERIC Educational Resources Information Center

Tillema, Marion; van den Bergh, Huub; Rijlaarsdam, Gert; Sanders, Ted

2011-01-01

Current theory about writing states that the quality of (meta)cognitive processing (i.e. planning, text production, revising, et cetera) is, at least partly, determined by the temporal distribution of (meta)cognitive activities across task execution. Put simply, the quality of task execution is determined more by "when" activities are applied than…

Teleoperation, telerobotics, and telepresence in surgery.

PubMed

Satava, R M; Simon, I B

1993-06-01

The concepts of teleoperation, telerobotics, and telepresence are presented and defined. Current surgical systems, some in clinical practice and others in prototype demonstration, are used to illustrate each of these principles. The importance and impact of these technologies and their relation to other advanced technologies are illustrated to project a framework for the future of surgery.

Automation and robotics

NASA Technical Reports Server (NTRS)

Montemerlo, Melvin

1988-01-01

The Autonomous Systems focus on the automation of control systems for the Space Station and mission operations. Telerobotics focuses on automation for in-space servicing, assembly, and repair. The Autonomous Systems and Telerobotics each have a planned sequence of integrated demonstrations showing the evolutionary advance of the state-of-the-art. Progress is briefly described for each area of concern.

Diverse applications of advanced man-telerobot interfaces

NASA Technical Reports Server (NTRS)

Mcaffee, Douglas A.

1991-01-01

Advancements in man-machine interfaces and control technologies used in space telerobotics and teleoperators have potential application wherever human operators need to manipulate multi-dimensional spatial relationships. Bilateral six degree-of-freedom position and force cues exchanged between the user and a complex system can broaden and improve the effectiveness of several diverse man-machine interfaces.

Design, development and evaluation of a compact telerobotic catheter navigation system.

PubMed

Tavallaei, Mohammad Ali; Gelman, Daniel; Lavdas, Michael Konstantine; Skanes, Allan C; Jones, Douglas L; Bax, Jeffrey S; Drangova, Maria

2016-09-01

Remote catheter navigation systems protect interventionalists from scattered ionizing radiation. However, these systems typically require specialized catheters and extensive operator training. A new compact and sterilizable telerobotic system is described, which allows remote navigation of conventional tip-steerable catheters, with three degrees of freedom, using an interface that takes advantage of the interventionalist's existing dexterity skills. The performance of the system is evaluated ex vivo and in vivo for remote catheter navigation and ablation delivery. The system has absolute errors of 0.1 ± 0.1 mm and 7 ± 6° over 100 mm of axial motion and 360° of catheter rotation, respectively. In vivo experiments proved the safety of the proposed telerobotic system and demonstrated the feasibility of remote navigation and delivery of ablation. The proposed telerobotic system allows the interventionalist to use conventional steerable catheters; while maintaining a safe distance from the radiation source, he/she can remotely navigate the catheter and deliver ablation lesions. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Commercial users panel

NASA Technical Reports Server (NTRS)

Byrd, Joseph S.; Flatau, Carl; Hodge, David C.; Hollis, Ralph; Leach, Eugene F.; Gilbert, Ray; Cleland, John; Leifer, Larry; Naser, Joseph; Schmuter, Samson D.

1987-01-01

The discussions of motives and requirements for telerobotics application demonstrated that, in many cases, lack of progress was a result not of limited opportunities but of inadequate mechanisms and resources for promoting opportunities. Support for this conclusion came from Telerobotics, Inc., one of the few companies devoted primarily to telerobot systems. They have produced units for such diverse applications as nuclear fusion research, particle accelerators, cryogenics, firefighting, marine biology/undersea systems and nuclear mobile robotics. Mr. Flatau offered evidence that telerobotics research is only rarely supported by the private sector and that it often presents a difficult market. Questions on the mechanisms contained within the NASA technology transfer process for promoting commercial opportunities were fielded by Ray Gilbert and Tom Walters. A few points deserve emphasis: (1) NASA/industry technology transfer occurs in both directions and NASA recognizes the opportunity to learn a great deal from industry in the fields of automation and robotics; (2) promotion of technology transfer projects takes a demand side approach, with requests to industry for specific problem identification. NASA then proposes possible solutions; and (3) comittment ofmotivated and technically qualified people on each end of a technology transfer is essential.

The role of executive functioning in children's attentional pain control: an experimental analysis.

PubMed

Verhoeven, Katrien; Dick, Bruce; Eccleston, Christopher; Goubert, Liesbet; Crombez, Geert

2014-02-01

Directing attention away from pain is often used in children's pain treatment programs to control pain. However, empirical evidence concerning its effectiveness is inconclusive. We therefore sought to understand other influencing factors, including executive function and its role in the pain experience. This study investigates the role of executive functioning in the effectiveness of distraction. School children (n=164) completed executive functioning tasks (inhibition, switching, and working memory) and performed a cold-pressor task. One half of the children simultaneously performed a distracting tone-detection task; the other half did not. Results showed that participants in the distraction group were engaged in the distraction task and were reported to pay significantly less attention to pain than controls. Executive functioning influenced distraction task engagement. More specifically, participants with good inhibition and working memory abilities performed the distraction task better; participants with good switching abilities reported having paid more attention to the distraction task. Furthermore, distraction was found to be ineffective in reducing pain intensity and affect. Executive functioning did not influence the effectiveness of distraction. However, a relationship was found between executive functioning and pain affect, indicating that participants with good inhibition and working memory abilities experienced the cold-pressor task as less stressful and unpleasant. Our findings suggest that distraction as a process for managing pain is complex. While it appears that executive function may play a role in adult distraction, in this study it did not direct attention away from pain. It may instead be involved in the overall pain experience. Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Clustering execution in a processing system to increase power savings

DOEpatents

Bose, Pradip; Buyuktosunoglu, Alper; Jacobson, Hans M.; Vega, Augusto J.

2018-03-20

Embodiments relate to clustering execution in a processing system. An aspect includes accessing a control flow graph that defines a data dependency and an execution sequence of a plurality of tasks of an application that executes on a plurality of system components. The execution sequence of the tasks in the control flow graph is modified as a clustered control flow graph that clusters active and idle phases of a system component while maintaining the data dependency. The clustered control flow graph is sent to an operating system, where the operating system utilizes the clustered control flow graph for scheduling the tasks.

Executive function in middle childhood and the relationship with theory of mind.

PubMed

Wilson, Jennifer; Andrews, Glenda; Hogan, Christy; Wang, Si; Shum, David H K

2018-01-01

A group of 126 typically developing children (aged 5-12 years) completed three cool executive function tasks (spatial working memory, stop signal, intra-extra dimensional shift), two hot executive function tasks (gambling, delay of gratification), one advanced theory of mind task (strange stories with high versus low affective tone), and a vocabulary test. Older children performed better than younger children, consistent with the protracted development of hot and cool executive functions and theory of mind. Multiple regression analyses showed that hot and cool executive functions were correlated but they predicted theory of mind in different ways.

ROTEX-TRIIFEX: Proposal for a joint FRG-USA telerobotic flight experiment

NASA Technical Reports Server (NTRS)

Hirzinger, G.; Bejczy, A. K.

1989-01-01

The concepts and main elements of a RObot Technology EXperiment (ROTEX) proposed to fly with the next German spacelab mission, D2, are presented. It provides a 1 meter size, six axis robot inside a spacelab rack, equipped with a multisensory gripper (force-torque sensors, an array of range finders, and mini stereo cameras). The robot will perform assembly and servicing tasks in a generic way, and will grasp a floating object. The man machine and supervisory control concepts for teleoperation from the spacelab and from ground are discussed. The predictive estimation schemes for an extensive use of time-delay compensating 3D computer graphics are explained.

Test and training simulator for ground-based teleoperated in-orbit servicing

NASA Technical Reports Server (NTRS)

Schaefer, Bernd E.

1989-01-01

For the Post-IOC(In-Orbit Construction)-Phase of COLUMBUS it is intended to use robotic devices for the routine operations of ground-based teleoperated In-Orbit Servicing. A hardware simulator for verification of the relevant in-orbit operations technologies, the Servicing Test Facility, is necessary which mainly will support the Flight Control Center for the Manned Space-Laboratories for operational specific tasks like system simulation, training of teleoperators, parallel operation simultaneously to actual in-orbit activities and for the verification of the ground operations segment for telerobotics. The present status of definition for the facility functional and operational concept is described.

Episodic feeling-of-knowing accuracy and cued recall in the elderly: evidence for double dissociation involving executive functioning and processing speed.

PubMed

Perrotin, Audrey; Isingrini, Michel; Souchay, Céline; Clarys, David; Taconnat, Laurence

2006-05-01

This research investigated adult age differences in a metamemory monitoring task-episodic feeling-of-knowing (FOK) and in an episodic memory task-cued recall. Executive functioning and processing speed were examined as mediators of these age differences. Young and elderly adults were administered an episodic FOK task, a cued recall task, executive tests and speed tests. Age-related decline was observed on all the measures. Correlation analyses revealed a pattern of double dissociation which indicates a specific relationship between executive score and FOK accuracy, and between speed score and cued recall. When executive functioning and processing speed were evaluated concurrently on FOK and cued recall variables, hierarchical regression analyses showed that executive score was a better mediator of age-related variance in FOK, and that speed score was the better mediator of age-related variance in cued recall.

The Role of Control Functions in Mentalizing: Dual-Task Studies of Theory of Mind and Executive Function

ERIC Educational Resources Information Center

Bull, Rebecca; Phillips, Louise H.; Conway, Claire A.

2008-01-01

Conflicting evidence has arisen from correlational studies regarding the role of executive control functions in Theory of Mind. The current study used dual-task manipulations of executive functions (inhibition, updating and switching) to investigate the role of these control functions in mental state and non-mental state tasks. The "Eyes"…

Differential Relationships between RAN Performance, Behaviour Ratings, and Executive Function Measures: Searching for a Double Dissociation

ERIC Educational Resources Information Center

Stringer, Ronald W.; Toplak, Maggie E.; Stanovich, Keith E.

2004-01-01

In this study, we investigated the relationships between rapid naming of letters, digits and colours, and reading ability and executive function. We gave fifty-six grade three and four children rapid automatised naming tasks using letters and digits as stimuli, executive function measures including the Stroop task, a working memory task and the…

Executive Functioning and Prospective Memory in Young Children

ERIC Educational Resources Information Center

Mahy, Caitlin E. V.; Moses, Louis J.

2011-01-01

The current study examined the role of executive functioning (EF) in children's prospective memory (PM) by assessing the effect of delay and number of intentions to-be-remembered on PM, as well as relations between PM and EF. Ninety-six 4-, 5-, and 6-year-olds completed a PM task and two executive function tasks. The PM task required children to…

Framework for Integrating Science Data Processing Algorithms Into Process Control Systems

NASA Technical Reports Server (NTRS)

Mattmann, Chris A.; Crichton, Daniel J.; Chang, Albert Y.; Foster, Brian M.; Freeborn, Dana J.; Woollard, David M.; Ramirez, Paul M.

2011-01-01

A software framework called PCS Task Wrapper is responsible for standardizing the setup, process initiation, execution, and file management tasks surrounding the execution of science data algorithms, which are referred to by NASA as Product Generation Executives (PGEs). PGEs codify a scientific algorithm, some step in the overall scientific process involved in a mission science workflow. The PCS Task Wrapper provides a stable operating environment to the underlying PGE during its execution lifecycle. If the PGE requires a file, or metadata regarding the file, the PCS Task Wrapper is responsible for delivering that information to the PGE in a manner that meets its requirements. If the PGE requires knowledge of upstream or downstream PGEs in a sequence of executions, that information is also made available. Finally, if information regarding disk space, or node information such as CPU availability, etc., is required, the PCS Task Wrapper provides this information to the underlying PGE. After this information is collected, the PGE is executed, and its output Product file and Metadata generation is managed via the PCS Task Wrapper framework. The innovation is responsible for marshalling output Products and Metadata back to a PCS File Management component for use in downstream data processing and pedigree. In support of this, the PCS Task Wrapper leverages the PCS Crawler Framework to ingest (during pipeline processing) the output Product files and Metadata produced by the PGE. The architectural components of the PCS Task Wrapper framework include PGE Task Instance, PGE Config File Builder, Config File Property Adder, Science PGE Config File Writer, and PCS Met file Writer. This innovative framework is really the unifying bridge between the execution of a step in the overall processing pipeline, and the available PCS component services as well as the information that they collectively manage.

The puzzle of processing speed, memory, and executive function impairments in schizophrenia: fitting the pieces together.

PubMed

Knowles, Emma E M; Weiser, Mark; David, Anthony S; Glahn, David C; Davidson, Michael; Reichenberg, Abraham

2015-12-01

Substantial impairment in performance on the digit-symbol substitution task in patients with schizophrenia is well established, which has been widely interpreted as denoting a specific impairment in processing speed. However, other higher order cognitive functions might be more critical to performance on this task. To date, this idea has not been rigorously investigated in patients with schizophrenia. Neuropsychological measures of processing speed, memory, and executive functioning were completed by 125 patients with schizophrenia and 272 control subjects. We implemented a series of confirmatory factor and structural regression modeling to build an integrated model of processing speed, memory, and executive function with which to deconstruct the digit-symbol substitution task and characterize discrepancies between patients with schizophrenia and control subjects. The overall structure of the processing speed, memory, and executive function model was the same across groups (χ(2) = 208.86, p > .05), but the contribution of the specific cognitive domains to coding task performance differed significantly. When completing the task, control subjects relied on executive function and, indirectly, on working memory ability, whereas patients with schizophrenia used an alternative set of cognitive operations whereby they relied on the same processes required to complete verbal fluency tasks. Successful coding task performance relies predominantly on executive function, rather than processing speed or memory. Patients with schizophrenia perform poorly on this task because of an apparent lack of appropriate executive function input; they rely instead on an alternative cognitive pathway. Copyright © 2015 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

[Effects of planning and executive functions on young children's script change strategy: A developmental perspective].

PubMed

Yanaoka, Kaichi

2016-02-01

This research examined the effects of planning and executive functions on young children's (ages 3-to 5-years) strategies in changing scripts. Young children (N = 77) performed a script task (doll task), three executive function tasks (DCCS, red/blue task, and nine box task), a planning task, and a receptive vocabulary task. In the doll task, young children first enacted a "changing clothes" script, and then faced a situation in which some elements of the script were inappropriate. They needed to enact a script by compensating inappropriate items for the other-script items or by changing to the other script in advance. The results showed that shifting, a factor of executive function, had a positive influence on whether young children could compensate inappropriate items. In addition, planning was also an important factor that helped children to change to the other script in advance. These findings suggest that shifting and planning play different roles in using the two strategies appropriately when young children enact scripts in unexpected situations.

Income, neural executive processes, and preschool children's executive control.

PubMed

Ruberry, Erika J; Lengua, Liliana J; Crocker, Leanna Harris; Bruce, Jacqueline; Upshaw, Michaela B; Sommerville, Jessica A

2017-02-01

This study aimed to specify the neural mechanisms underlying the link between low household income and diminished executive control in the preschool period. Specifically, we examined whether individual differences in the neural processes associated with executive attention and inhibitory control accounted for income differences observed in performance on a neuropsychological battery of executive control tasks. The study utilized a sample of preschool-aged children (N = 118) whose families represented the full range of income, with 32% of families at/near poverty, 32% lower income, and 36% middle to upper income. Children completed a neuropsychological battery of executive control tasks and then completed two computerized executive control tasks while EEG data were collected. We predicted that differences in the event-related potential (ERP) correlates of executive attention and inhibitory control would account for income differences observed on the executive control battery. Income and ERP measures were related to performance on the executive control battery. However, income was unrelated to ERP measures. The findings suggest that income differences observed in executive control during the preschool period might relate to processes other than executive attention and inhibitory control.

Integrated prototyping environment for programmable automation

NASA Astrophysics Data System (ADS)

da Costa, Francis; Hwang, Vincent S. S.; Khosla, Pradeep K.; Lumia, Ronald

1992-11-01

We propose a rapid prototyping environment for robotic systems, based on tenets of modularity, reconfigurability and extendibility that may help build robot systems `faster, better, and cheaper.' Given a task specification, (e.g., repair brake assembly), the user browses through a library of building blocks that include both hardware and software components. Software advisors or critics recommend how blocks may be `snapped' together to speedily construct alternative ways to satisfy task requirements. Mechanisms to allow `swapping' competing modules for comparative test and evaluation studies are also included in the prototyping environment. After some iterations, a stable configuration or `wiring diagram' emerges. This customized version of the general prototyping environment still contains all the hooks needed to incorporate future improvements in component technologies and to obviate unplanned obsolescence. The prototyping environment so described is relevant for both interactive robot programming (telerobotics) and iterative robot system development (prototyping).

An enhanced Ada run-time system for real-time embedded processors

NASA Technical Reports Server (NTRS)

Sims, J. T.

1991-01-01

An enhanced Ada run-time system has been developed to support real-time embedded processor applications. The primary focus of this development effort has been on the tasking system and the memory management facilities of the run-time system. The tasking system has been extended to support efficient and precise periodic task execution as required for control applications. Event-driven task execution providing a means of task-asynchronous control and communication among Ada tasks is supported in this system. Inter-task control is even provided among tasks distributed on separate physical processors. The memory management system has been enhanced to provide object allocation and protected access support for memory shared between disjoint processors, each of which is executing a distinct Ada program.

Mars Surface Operations via Low-Latency Telerobotics from Phobos

NASA Technical Reports Server (NTRS)

Wright, Michael; Lupisella, Mark

2016-01-01

To help assess the feasibility and timing of Low-Latency Telerobotics (LLT) operations on Mars via a Phobos telecommand base, operations concepts (ops cons) and timelines for several representative sequences for Mars surface operations have been developed. A summary of these LLT sequences and timelines will be presented, along with associated assumptions, operational considerations, and challenges.

Compact Telerobot Hand

NASA Technical Reports Server (NTRS)

Rosheim, Mark; Trechsel, Hans

1993-01-01

Anthropomorphic telerobotic hand contains actuators, joints, sensors, and complex wiring harnesses. Glove protects interior components of hand from dirt and damage. Imitates motions of human fingers and wrist in lifelike and dexterous way. Incorporates pitch/yaw joints in wrist and head knuckles. Hand modular; so fingers removable, interchangeable units. Feature simplifies servicing and maintenance, which must be done frequently in such complex mechanism.

Geometric database maintenance using CCTV cameras and overlay graphics

NASA Astrophysics Data System (ADS)

Oxenberg, Sheldon C.; Landell, B. Patrick; Kan, Edwin

1988-01-01

An interactive graphics system using closed circuit television (CCTV) cameras for remote verification and maintenance of a geometric world model database has been demonstrated in GE's telerobotics testbed. The database provides geometric models and locations of objects viewed by CCTV cameras and manipulated by telerobots. To update the database, an operator uses the interactive graphics system to superimpose a wireframe line drawing of an object with known dimensions on a live video scene containing that object. The methodology used is multipoint positioning to easily superimpose a wireframe graphic on the CCTV image of an object in the work scene. An enhanced version of GE's interactive graphics system will provide the object designation function for the operator control station of the Jet Propulsion Laboratory's telerobot demonstration system.

Clustering execution in a processing system to increase power savings

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

Bose, Pradip; Buyuktosunoglu, Alper; Jacobson, Hans M.

Embodiments relate to clustering execution in a processing system. An aspect includes accessing a control flow graph that defines a data dependency and an execution sequence of a plurality of tasks of an application that executes on a plurality of system components. The execution sequence of the tasks in the control flow graph is modified as a clustered control flow graph that clusters active and idle phases of a system component while maintaining the data dependency. The clustered control flow graph is sent to an operating system, where the operating system utilizes the clustered control flow graph for scheduling themore » tasks.« less

Involvement of Spearman's g in conceptualisation versus execution of complex tasks.

PubMed

Carroll, Ellen L; Bright, Peter

2016-10-01

Strong correlations between measures of fluid intelligence (or Spearman's g) and working memory are widely reported in the literature, but there is considerable controversy concerning the nature of underlying mechanisms driving this relationship. In the four experiments presented here we consider the role of response conflict and task complexity in the context of real-time task execution demands (Experiments 1-3) and also address recent evidence that g confers an advantage at the level of task conceptualisation rather than (or in addition to) task execution (Experiment 4). We observed increased sensitivity of measured fluid intelligence to task performance in the presence (vs. the absence) of response conflict, and this relationship remained when task complexity was reduced. Performance-g correlations were also observed in the absence of response conflict, but only in the context of high task complexity. Further, we present evidence that differences in conceptualisation or 'modelling' of task instructions prior to execution had an important mediating effect on observed correlations, but only when the task encompassed a strong element of response inhibition. Our results suggest that individual differences in ability reflect, in large part, variability in the efficiency with which the relational complexity of task constraints are held in mind. It follows that fluid intelligence may support successful task execution through the construction of effective action plans via optimal allocation of limited resources. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Dedicated memory structure holding data for detecting available worker thread(s) and informing available worker thread(s) of task(s) to execute

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

Chiu, George L.; Eichenberger, Alexandre E.; O'Brien, John K. P.

The present disclosure relates generally to a dedicated memory structure (that is, hardware device) holding data for detecting available worker thread(s) and informing available worker thread(s) of task(s) to execute.

Motor and Executive Control in Repetitive Timing of Brief Intervals

ERIC Educational Resources Information Center

Holm, Linus; Ullen, Fredrik; Madison, Guy

2013-01-01

We investigated the causal role of executive control functions in the production of brief time intervals by means of a concurrent task paradigm. To isolate the influence of executive functions on timing from motor coordination effects, we dissociated executive load from the number of effectors used in the dual task situation. In 3 experiments,…

Latency and User Performance in Virtual Environments and Augmented Reality

NASA Technical Reports Server (NTRS)

Ellis, Stephen R.

2009-01-01

System rendering latency has been recognized by senior researchers, such as Professor Fredrick Brooks of UNC (Turing Award 1999), as a major factor limiting the realism and utility of head-referenced displays systems. Latency has been shown to reduce the user's sense of immersion within a virtual environment, disturb user interaction with virtual objects, and to contribute to motion sickness during some simulation tasks. Latency, however, is not just an issue for external display systems since finite nerve conduction rates and variation in transduction times in the human body's sensors also pose problems for latency management within the nervous system. Some of the phenomena arising from the brain's handling of sensory asynchrony due to latency will be discussed as a prelude to consideration of the effects of latency in interactive displays. The causes and consequences of the erroneous movement that appears in displays due to latency will be illustrated with examples of the user performance impact provided by several experiments. These experiments will review the generality of user sensitivity to latency when users judge either object or environment stability. Hardware and signal processing countermeasures will also be discussed. In particular the tuning of a simple extrapolative predictive filter not using a dynamic movement model will be presented. Results show that it is possible to adjust this filter so that the appearance of some latencies may be hidden without the introduction of perceptual artifacts such as overshoot. Several examples of the effects of user performance will be illustrated by three-dimensional tracking and tracing tasks executed in virtual environments. These experiments demonstrate classic phenomena known from work on manual control and show the need for very responsive systems if they are indented to support precise manipulation. The practical benefits of removing interfering latencies from interactive systems will be emphasized with some classic final examples from surgical telerobotics, and human-computer interaction.

“The Relationship between Executive Functioning, Processing Speed and White Matter Integrity in Multiple Sclerosis”

PubMed Central

Genova, Helen M.; DeLuca, John; Chiaravalloti, Nancy; Wylie, Glenn

2014-01-01

The primary purpose of the current study was to examine the relationship between performance on executive tasks and white matter integrity, assessed by diffusion tensor imaging (DTI) in Multiple Sclerosis (MS). A second aim was to examine how processing speed affects the relationship between executive functioning and FA. This relationship was examined in two executive tasks that rely heavily on processing speed: the Color-Word Interference Test and Trail-Making Test (Delis-Kaplan Executive Function System). It was hypothesized that reduced fractional anisotropy (FA) is related to poor performance on executive tasks in MS, but that this relationship would be affected by the statistical correction of processing speed from the executive tasks. 15 healthy controls and 25 persons with MS participated. Regression analyses were used to examine the relationship between executive functioning and FA, both before and after processing speed was removed from the executive scores. Before processing speed was removed from the executive scores, reduced FA was associated with poor performance on Color-Word Interference Test and Trail-Making Test in a diffuse network including corpus callosum and superior longitudinal fasciculus. However, once processing speed was removed, the relationship between executive functions and FA was no longer significant on the Trail Making test, and significantly reduced and more localized on the Color-Word Interference Test. PMID:23777468

A multitasking general executive for compound continuous tasks.

PubMed

Salvucci, Dario D

2005-05-06

As cognitive architectures move to account for increasingly complex real-world tasks, one of the most pressing challenges involves understanding and modeling human multitasking. Although a number of existing models now perform multitasking in real-world scenarios, these models typically employ customized executives that schedule tasks for the particular domain but do not generalize easily to other domains. This article outlines a general executive for the Adaptive Control of Thought-Rational (ACT-R) cognitive architecture that, given independent models of individual tasks, schedules and interleaves the models' behavior into integrated multitasking behavior. To demonstrate the power of the proposed approach, the article describes an application to the domain of driving, showing how the general executive can interleave component subtasks of the driving task (namely, control and monitoring) and interleave driving with in-vehicle secondary tasks (radio tuning and phone dialing). 2005 Lawrence Erlbaum Associates, Inc.

Estimation Accuracy on Execution Time of Run-Time Tasks in a Heterogeneous Distributed Environment

PubMed Central

Liu, Qi; Cai, Weidong; Jin, Dandan; Shen, Jian; Fu, Zhangjie; Liu, Xiaodong; Linge, Nigel

2016-01-01

Distributed Computing has achieved tremendous development since cloud computing was proposed in 2006, and played a vital role promoting rapid growth of data collecting and analysis models, e.g., Internet of things, Cyber-Physical Systems, Big Data Analytics, etc. Hadoop has become a data convergence platform for sensor networks. As one of the core components, MapReduce facilitates allocating, processing and mining of collected large-scale data, where speculative execution strategies help solve straggler problems. However, there is still no efficient solution for accurate estimation on execution time of run-time tasks, which can affect task allocation and distribution in MapReduce. In this paper, task execution data have been collected and employed for the estimation. A two-phase regression (TPR) method is proposed to predict the finishing time of each task accurately. Detailed data of each task have drawn interests with detailed analysis report being made. According to the results, the prediction accuracy of concurrent tasks’ execution time can be improved, in particular for some regular jobs. PMID:27589753

Video game practice optimizes executive control skills in dual-task and task switching situations.

PubMed

Strobach, Tilo; Frensch, Peter A; Schubert, Torsten

2012-05-01

We examined the relation of action video game practice and the optimization of executive control skills that are needed to coordinate two different tasks. As action video games are similar to real life situations and complex in nature, and include numerous concurrent actions, they may generate an ideal environment for practicing these skills (Green & Bavelier, 2008). For two types of experimental paradigms, dual-task and task switching respectively; we obtained performance advantages for experienced video gamers compared to non-gamers in situations in which two different tasks were processed simultaneously or sequentially. This advantage was absent in single-task situations. These findings indicate optimized executive control skills in video gamers. Similar findings in non-gamers after 15 h of action video game practice when compared to non-gamers with practice on a puzzle game clarified the causal relation between video game practice and the optimization of executive control skills. Copyright © 2012 Elsevier B.V. All rights reserved.

Executive and motivational inhibition: associations with self-report measures related to inhibition.

PubMed

Shuster, Jill; Toplak, Maggie E

2009-06-01

Inhibition involves the withholding or suppressing of attention or responses to irrelevant or distracting stimuli. We examined the relationship between five experimental tasks of inhibition, represented by two measures of executive, intentional control inhibition and three measures of motivational inhibition characterized by bottom-up interruption of affective and reward/punishment sensitive mechanisms. Associations between these experimental tasks with three self-report measures related to inhibition were also examined. Correlational analyses indicated a small but significant association between the measures in the executive domain (stop task and Stroop task), but a lack of associations between the measures in the motivational domain (emotional Stroop task, a card playing task involving rewards and punishments, and a gambling task). Both measures of executive and motivational inhibition entered as significant predictors on the self-report measures related to inhibition in simultaneous regression analyses, but not consistently in the expected direction. The results suggest that inhibition is not a unitary construct, and demonstrate an association between experimental measures of inhibition and self-report measures related to inhibition.

Do Tasks Make a Difference? Accounting for Heterogeneity of Performance of Children with Reading Difficulties on Tasks of Executive Function: Findings from a Meta-Analysis

ERIC Educational Resources Information Center

Booth, Josephine N.; Boyle, James M. E.; Kelly, Steve W.

2010-01-01

Research studies have implicated executive functions in reading difficulties (RD). But while some studies have found children with RD to be impaired on tasks of executive function other studies report unimpaired performance. A meta-analysis was carried out to determine whether these discrepant findings can be accounted for by differences in the…

Manipulator control and mechanization: A telerobot subsystem

NASA Technical Reports Server (NTRS)

Hayati, S.; Wilcox, B.

1987-01-01

The short- and long-term autonomous robot control activities in the Robotics and Teleoperators Research Group at the Jet Propulsion Laboratory (JPL) are described. This group is one of several involved in robotics and is an integral part of a new NASA robotics initiative called Telerobot program. A description of the architecture, hardware and software, and the research direction in manipulator control is given.

Robonaut testing

NASA Image and Video Library

2013-08-05

ISS036-E-029110 (6 Aug. 2013) --- In the International Space Station’s Destiny laboratory, NASA astronaut Chris Cassidy, Expedition 36 flight engineer, wears tele-operation gear consisting of a vest, gloves and visor to telerobotically test Robonaut 2’s maneuvers. Cassidy was able to manipulate R2’s head, neck, arms and fingers telerobotically through his own movements as well as through verbal commands.

Robonaut testing

NASA Image and Video Library

2013-08-05

ISS036-E-029109 (6 Aug. 2013) --- In the International Space Station’s Destiny laboratory, NASA astronaut Chris Cassidy, Expedition 36 flight engineer, wears tele-operation gear consisting of a vest, gloves and visor to telerobotically test Robonaut 2’s maneuvers. Cassidy was able to manipulate R2’s head, neck, arms and fingers telerobotically through his own movements as well as through verbal commands.

Cassidy with Robonaut 2

NASA Image and Video Library

2013-08-28

ISS036-E-038293 (28 Aug. 2013) --- In the International Space Station's Destiny laboratory, NASA astronaut Chris Cassidy, Expedition 36 flight engineer, wears tele-operation gear consisting of a vest, gloves and visor to telerobotically test Robonaut 2's maneuvers. Cassidy was able to manipulate R2's head, neck, arms and fingers telerobotically through his own movements as well as through verbal commands.

Robonaut 2 Teleops

NASA Image and Video Library

2013-07-22

ISS036-E-029140 (6 Aug. 2013) --- In the International Space Station?s Destiny laboratory, NASA astronaut Chris Cassidy, Expedition 36 flight engineer, wears tele-operation gear consisting of a vest, gloves and visor to telerobotically test Robonaut 2?s maneuvers. Cassidy was able to manipulate R2?s head, neck, arms and fingers telerobotically through his own movements as well as through verbal commands.

Robonaut 2 Teleops

NASA Image and Video Library

2013-07-22

ISS036-E-029144 (6 Aug. 2013) --- In the International Space Station?s Destiny laboratory, NASA astronaut Chris Cassidy, Expedition 36 flight engineer, wears tele-operation gear consisting of a vest, gloves and visor to telerobotically test Robonaut 2?s maneuvers. Cassidy was able to manipulate R2?s head, neck, arms and fingers telerobotically through his own movements as well as through verbal commands.

Telerobotic Perception During Asteroid and Mars Regolith Operations Project

NASA Technical Reports Server (NTRS)

Gaddis, Steven; Zeitlin, Nancy (Compiler); Mueller, Robert (Compiler)

2015-01-01

Current space telerobotic systems are constrained to only operating in bright light and dust-free conditions. This project will study the effects of difficult lighting and dust conditions on telerobotic perception systems to better assess and refine regolith operations on other neighboring celestial bodies. In partnership with Embry-Riddle Aeronautical University and Caterpillar, Inc., optical, LiDAR and RADAR sensing equipment will be used in performing the study. This project will create a known dust environment in the Swamp Works Granular Mechanics & Regolith Operations (GMRO) Laboratory regolith test bin to characterize the behavior of the sensing equipment in various calibrated lighting and dust conditions. It will also identify potential methods for mitigating the impacts of these undesirable conditions on the performance of the sensing equipment. Enhancing the capability of telerobotic perception systems will help improve life on earth for those working in dangerous, dusty mining conditions, as well as help advance the same technologies used for safer self-driving automobiles in various lighting and weather conditions. It will also prove to be a critical skill needed for advancing robotic and human exploration throughout our solar system, for activities such as mining on an asteroid or pioneering the first colony on Mars.

Age-Related Differences in Listening Effort During Degraded Speech Recognition.

PubMed

Ward, Kristina M; Shen, Jing; Souza, Pamela E; Grieco-Calub, Tina M

The purpose of the present study was to quantify age-related differences in executive control as it relates to dual-task performance, which is thought to represent listening effort, during degraded speech recognition. Twenty-five younger adults (YA; 18-24 years) and 21 older adults (OA; 56-82 years) completed a dual-task paradigm that consisted of a primary speech recognition task and a secondary visual monitoring task. Sentence material in the primary task was either unprocessed or spectrally degraded into 8, 6, or 4 spectral channels using noise-band vocoding. Performance on the visual monitoring task was assessed by the accuracy and reaction time of participants' responses. Performance on the primary and secondary task was quantified in isolation (i.e., single task) and during the dual-task paradigm. Participants also completed a standardized psychometric measure of executive control, including attention and inhibition. Statistical analyses were implemented to evaluate changes in listeners' performance on the primary and secondary tasks (1) per condition (unprocessed vs. vocoded conditions); (2) per task (single task vs. dual task); and (3) per group (YA vs. OA). Speech recognition declined with increasing spectral degradation for both YA and OA when they performed the task in isolation or concurrently with the visual monitoring task. OA were slower and less accurate than YA on the visual monitoring task when performed in isolation, which paralleled age-related differences in standardized scores of executive control. When compared with single-task performance, OA experienced greater declines in secondary-task accuracy, but not reaction time, than YA. Furthermore, results revealed that age-related differences in executive control significantly contributed to age-related differences on the visual monitoring task during the dual-task paradigm. OA experienced significantly greater declines in secondary-task accuracy during degraded speech recognition than YA. These findings are interpreted as suggesting that OA expended greater listening effort than YA, which may be partially attributed to age-related differences in executive control.

Components of executive functioning in metamemory.

PubMed

Mäntylä, Timo; Rönnlund, Michael; Kliegel, Matthias

2010-10-01

This study examined metamemory in relation to three basic executive functions (set shifting, working memory updating, and response inhibition) measured as latent variables. Young adults (Experiment 1) and middle-aged adults (Experiment 2) completed a set of executive functioning tasks and the Prospective and Retrospective Memory Questionnaire (PRMQ). In Experiment 1, source recall and face recognition tasks were included as indicators of objective memory performance. In both experiments, analyses of the executive functioning data yielded a two-factor solution, with the updating and inhibition tasks constituting a common factor and the shifting tasks a separate factor. Self-reported memory problems showed low predictive validity, but subjective and objective memory performance were related to different components of executive functioning. In both experiments, set shifting, but not updating and inhibition, was related to PRMQ, whereas source recall showed the opposite pattern of correlations in Experiment 1. These findings suggest that metamemorial judgments reflect selective effects of executive functioning and that individual differences in mental flexibility contribute to self-beliefs of efficacy.

“No-o-o-o Peeking”: Preschoolers’ Executive Control, Social Competence, and Classroom Adjustment

PubMed Central

Denham, Susanne A.; Bassett, Hideko H.; Sirotkin, Yana S.; Brown, Chavaughn; Morris, Carol S.

2015-01-01

The goals of this study were to evaluate (1) how specific aspects of executive control, briefly assessed, predict social competence and classroom adjustment during preschool; and (2) differences between two aspects of executive control, according to child’s age, socioeconomic risk status, and gender. The facets of executive control were defined as cool executive control (CEC; affectively neutral, slow acting, and late developing) and hot executive control (HEC; more emotional, fast acting, and early developing). Two hundred eighty-seven 3- to 5-year-old children from private child care and Head Start centers were directly assessed during executive control tasks, and preschool teachers provided information on their school success. Aspects of executive control varied with age, socioeconomic risk, and gender. Specifically, older children performed better on CEC tasks across three age levels; for HEC tasks, change was seen only between 3-year-olds and 4-year-olds. Children of mothers with less formal education performed less well on CEC than those whose mothers had more education; girls performed better than boys on HEC tasks. Further, facets of executive control were differentially related to later social competence and classroom adjustment. HEC predicted social competence, whereas CEC uniquely predicted classroom adjustment. Implications for everyday practice and specific curricula formulation are discussed. PMID:26166925

Can task-switching training enhance executive control functioning in children with attention deficit/-hyperactivity disorder?

PubMed

Kray, Jutta; Karbach, Julia; Haenig, Susann; Freitag, Christine

2011-01-01

The key cognitive impairments of children with attention deficit/-hyperactivity disorder (ADHD) include executive control functions such as inhibitory control, task-switching, and working memory (WM). In this training study we examined whether task-switching training leads to improvements in these functions. Twenty children with combined type ADHD and stable methylphenidate medication performed a single-task and a task-switching training in a crossover training design. The children were randomly assigned to one of two groups. One group started with the single-task training and then performed the task-switching training and the other group vice versa. The effectiveness of the task-switching training was measured as performance improvements (relative to the single-task training) on a structurally similar but new switching task and on other executive control tasks measuring inhibitory control and verbal WM as well as on fluid intelligence (reasoning). The children in both groups showed improvements in task-switching, that is, a reduction of switching costs, but not in performing the single-tasks across four training sessions. Moreover, the task-switching training lead to selective enhancements in task-switching performance, that is, the reduction of task-switching costs was found to be larger after task-switching than after single-task training. Similar selective improvements were observed for inhibitory control and verbal WM, but not for reasoning. Results of this study suggest that task-switching training is an effective cognitive intervention that helps to enhance executive control functioning in children with ADHD.

Can Task-Switching Training Enhance Executive Control Functioning in Children with Attention Deficit/-Hyperactivity Disorder?

PubMed Central

Kray, Jutta; Karbach, Julia; Haenig, Susann; Freitag, Christine

2012-01-01

The key cognitive impairments of children with attention deficit/-hyperactivity disorder (ADHD) include executive control functions such as inhibitory control, task-switching, and working memory (WM). In this training study we examined whether task-switching training leads to improvements in these functions. Twenty children with combined type ADHD and stable methylphenidate medication performed a single-task and a task-switching training in a crossover training design. The children were randomly assigned to one of two groups. One group started with the single-task training and then performed the task-switching training and the other group vice versa. The effectiveness of the task-switching training was measured as performance improvements (relative to the single-task training) on a structurally similar but new switching task and on other executive control tasks measuring inhibitory control and verbal WM as well as on fluid intelligence (reasoning). The children in both groups showed improvements in task-switching, that is, a reduction of switching costs, but not in performing the single-tasks across four training sessions. Moreover, the task-switching training lead to selective enhancements in task-switching performance, that is, the reduction of task-switching costs was found to be larger after task-switching than after single-task training. Similar selective improvements were observed for inhibitory control and verbal WM, but not for reasoning. Results of this study suggest that task-switching training is an effective cognitive intervention that helps to enhance executive control functioning in children with ADHD. PMID:22291628

Performance and stability of telemanipulators using bilateral impedance control. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Moore, Christopher Lane

1991-01-01

A new method of control for telemanipulators called bilateral impedance control is investigated. This new method differs from previous approaches in that interaction forces are used as the communication signals between the master and slave robots. The new control architecture has several advantages: (1) It allows the master robot and the slave robot to be stabilized independently without becoming involved in the overall system dynamics; (2) It permits the system designers to arbitrarily specify desired performance characteristics such as the force and position ratios between the master and slave; (3) The impedance at both ends of the telerobotic system can be modulated to suit the requirements of the task. The main goals of the research are to characterize the performance and stability of the new control architecture. The dynamics of the telerobotic system are described by a bond graph model that illustrates how energy is transformed, stored, and dissipated. Performance can be completely described by a set of three independent parameters. These parameters are fundamentally related to the structure of the H matrix that regulates the communication of force signals within the system. Stability is analyzed with two mathematical techniques: the Small Gain Theorem and the Multivariable Nyquist Criterion. The theoretical predictions for performance and stability are experimentally verified by implementing the new control architecture on a multidegree of freedom telemanipulator.

The effects of bilingualism on toddlers’ executive functioning

PubMed Central

Poulin-Dubois, Diane; Blaye, Agnes; Coutya, Julie; Bialystok, Ellen

2015-01-01

Bilingual children have been shown to outperform monolingual children on tasks measuring executive functioning skills. This advantage is usually attributed to bilinguals’ extensive practice in exercising selective attention and cognitive flexibility during language use because both languages are active when one of them is being used. We examined whether this advantage is observed in 24-month-olds who have had much less experience in language production. A battery of executive functioning tasks and the cognitive scale of the Bayley test were administered to 63 monolingual and bilingual children. Native bilingual children performed significantly better than monolingual children on the Stroop task, with no difference between groups on the other tasks, confirming the specificity of bilingual effects to conflict tasks reported in older children. These results demonstrate that bilingual advantages in executive control emerge at an age not previously shown. PMID:21122877

Thermal feedback in virtual reality and telerobotic systems

NASA Technical Reports Server (NTRS)

Zerkus, Mike; Becker, Bill; Ward, Jon; Halvorsen, Lars

1994-01-01

A new concept has been developed that allows temperature to be part of the virtual world. The Displaced Temperature Sensing System (DTSS) can 'display' temperature in a virtual reality system.The DTSS can also serve as a feedback device for telerobotics. For virtual reality applications the virtual world software would be required to have a temperature map of its world. By whatever means (magnetic tracker, ultrasound tracker, etc.) the hand and fingers, which have been instrumented with thermodes, would be tracked. The temperature associated with the current position would be transmitted to the DRSS via a serial data link. The DTSS would provide that temperature to the fingers. For telerobotic operation the function of the DTSS is to transmit a temperature from a remote location to the fingers where the temperature can be felt.

The da Vinci telerobotic surgical system: the virtual operative field and telepresence surgery.

PubMed

Ballantyne, Garth H; Moll, Fred

2003-12-01

The United States Department of Defense developed the telepresence surgery concept to meet battlefield demands. The da Vinci telerobotic surgery system evolved from these efforts. In this article, the authors describe the components of the da Vinci system and explain how the surgeon sits at a computer console, views a three-dimensional virtual operative field, and performs the operation by controlling robotic arms that hold the stereoscopic video telescope and surgical instruments that simulate hand motions with seven degrees of freedom. The three-dimensional imaging and handlike motions of the system facilitate advanced minimally invasive thoracic, cardiac, and abdominal procedures. da Vinci has recently released a second generation of telerobots with four arms and will continue to meet the evolving challenges of surgery.

Performing a global barrier operation in a parallel computer

DOEpatents

Archer, Charles J; Blocksome, Michael A; Ratterman, Joseph D; Smith, Brian E

2014-12-09

Executing computing tasks on a parallel computer that includes compute nodes coupled for data communications, where each compute node executes tasks, with one task on each compute node designated as a master task, including: for each task on each compute node until all master tasks have joined a global barrier: determining whether the task is a master task; if the task is not a master task, joining a single local barrier; if the task is a master task, joining the global barrier and the single local barrier only after all other tasks on the compute node have joined the single local barrier.

Image Display and Manipulation System (IDAMS) program documentation, Appendixes A-D. [including routines, convolution filtering, image expansion, and fast Fourier transformation

NASA Technical Reports Server (NTRS)

Cecil, R. W.; White, R. A.; Szczur, M. R.

1972-01-01

The IDAMS Processor is a package of task routines and support software that performs convolution filtering, image expansion, fast Fourier transformation, and other operations on a digital image tape. A unique task control card for that program, together with any necessary parameter cards, selects each processing technique to be applied to the input image. A variable number of tasks can be selected for execution by including the proper task and parameter cards in the input deck. An executive maintains control of the run; it initiates execution of each task in turn and handles any necessary error processing.

Autonomic Cardiovascular Control and Executive Function in Chronic Hypotension.

PubMed

Duschek, Stefan; Hoffmann, Alexandra; Reyes Del Paso, Gustavo A; Ettinger, Ulrich

2017-06-01

Chronic low blood pressure (hypotension) is characterized by complaints such as fatigue, reduced drive, dizziness, and cold limbs. Additionally, deficits in attention and memory have been observed. Autonomic dysregulation is considered to be involved in the origin of this condition. The study explored autonomic cardiovascular control in the context of higher cognitive processing (executive function) in hypotension. Hemodynamic recordings were performed in 40 hypotensive and 40 normotensive participants during execution of four classical executive function tasks (number-letter task, n-back task, continuous performance test, and flanker task). Parameters of cardiac sympathetic control, i.e., stroke volume, cardiac output, pre-ejection period, total peripheral resistance, and parasympathetic control, i.e., respiratory sinus arrhythmia and baroreflex sensitivity, were obtained. The hypotensive group exhibited lower stroke volume and cardiac output, as well as higher pre-ejection period and baroreflex sensitivity during task execution. Increased error rates in hypotensive individuals were observed in the n-back and flanker tasks. In the total sample, there were positive correlations of error rates with pre-ejection period, baroreflex sensitivity and respiratory sinus arrhythmia, and negative correlations with cardiac output. Group differences in stroke volume, cardiac output, and pre-ejection period suggest diminished beta-adrenergic myocardial drive during executive function processing in hypotension, in addition to increased baroreflex function. Although further research is warranted to quantify the extent of executive function impairment in hypotension, the results from correlation analysis add evidence to the notion that higher sympathetic inotropic influences and reduced parasympathetic cardiac influences are accompanied by better cognitive performance.

Investigating the effects of caffeine on executive functions using traditional Stroop and a new ecologically-valid virtual reality task, the Jansari assessment of Executive Functions (JEF(©)).

PubMed

Soar, K; Chapman, E; Lavan, N; Jansari, A S; Turner, J J D

2016-10-01

Caffeine has been shown to have effects on certain areas of cognition, but in executive functioning the research is limited and also inconsistent. One reason could be the need for a more sensitive measure to detect the effects of caffeine on executive function. This study used a new non-immersive virtual reality assessment of executive functions known as JEF(©) (the Jansari Assessment of Executive Function) alongside the 'classic' Stroop Colour-Word task to assess the effects of a normal dose of caffeinated coffee on executive function. Using a double-blind, counterbalanced within participants procedure 43 participants were administered either a caffeinated or decaffeinated coffee and completed the 'JEF(©)' and Stroop tasks, as well as a subjective mood scale and blood pressure pre- and post condition on two separate occasions a week apart. JEF(©) yields measures for eight separate aspects of executive functions, in addition to a total average score. Findings indicate that performance was significantly improved on the planning, creative thinking, event-, time- and action-based prospective memory, as well as total JEF(©) score following caffeinated coffee relative to the decaffeinated coffee. The caffeinated beverage significantly decreased reaction times on the Stroop task, but there was no effect on Stroop interference. The results provide further support for the effects of a caffeinated beverage on cognitive functioning. In particular, it has demonstrated the ability of JEF(©) to detect the effects of caffeine across a number of executive functioning constructs, which weren't shown in the Stroop task, suggesting executive functioning improvements as a result of a 'typical' dose of caffeine may only be detected by the use of more real-world, ecologically valid tasks. Copyright © 2016 Elsevier Ltd. All rights reserved.

Out with the Old and in with the New—Is Backward Inhibition a Domain-Specific Process?

PubMed Central

Menghini, Deny; Vicari, Stefano; Petrosini, Laura; Ferlazzo, Fabio

2015-01-01

Effective task switching is supported by the inhibition of the just executed task, so that potential interference from previously executed tasks is adaptively counteracted. This inhibitory mechanism, named Backward Inhibition (BI), has been inferred from the finding that switching back to a recently executed task (A-B-A task sequence) is harder than switching back to a less recently executed task (C-B-A task sequence). Despite the fact that BI effects do impact performance on everyday life activities, up to now it is still not clear whether the BI represents an amodal and material-independent process or whether it interacts with the task material. To address this issue, a group of individuals with Williams syndrome (WS) characterized by specific difficulties in maintaining and processing visuo-spatial, but not verbal, information, and a mental age- and gender-matched group of typically developing (TD) children were subjected to three task-switching experiments requiring verbal or visuo-spatial material to be processed. Results showed that individuals with WS exhibited a normal BI effect during verbal task-switching, but a clear deficit during visuo-spatial task-switching. Overall, our findings demonstrating that the BI is a material-specific process have important implications for theoretical models of cognitive control and its architecture. PMID:26565628

Executive Function and Early Reading Skills

ERIC Educational Resources Information Center

Foy, Judith G.; Mann, Virginia A.

2013-01-01

The purpose of this study was to examine how executive function skills in verbal and nonverbal auditory tasks are related to early reading skills in beginning readers. Kindergarteners (N = 41, aged 5 years) completed verbal (phonemes) and nonverbal (environmental sounds) Continuous Performance tasks yielding measures of executive function (misses,…

Brain effective connectivity during motor-imagery and execution following stroke and rehabilitation.

PubMed

Bajaj, Sahil; Butler, Andrew J; Drake, Daniel; Dhamala, Mukesh

2015-01-01

Brain areas within the motor system interact directly or indirectly during motor-imagery and motor-execution tasks. These interactions and their functionality can change following stroke and recovery. How brain network interactions reorganize and recover their functionality during recovery and treatment following stroke are not well understood. To contribute to answering these questions, we recorded blood oxygenation-level dependent (BOLD) functional magnetic resonance imaging (fMRI) signals from 10 stroke survivors and evaluated dynamical causal modeling (DCM)-based effective connectivity among three motor areas: primary motor cortex (M1), pre-motor cortex (PMC) and supplementary motor area (SMA), during motor-imagery and motor-execution tasks. We compared the connectivity between affected and unaffected hemispheres before and after mental practice and combined mental practice and physical therapy as treatments. The treatment (intervention) period varied in length between 14 to 51 days but all patients received the same dose of 60 h of treatment. Using Bayesian model selection (BMS) approach in the DCM approach, we found that, after intervention, the same network dominated during motor-imagery and motor-execution tasks but modulatory parameters suggested a suppressive influence of SM A on M1 during the motor-imagery task whereas the influence of SM A on M1 was unrestricted during the motor-execution task. We found that the intervention caused a reorganization of the network during both tasks for unaffected as well as for the affected hemisphere. Using Bayesian model averaging (BMA) approach, we found that the intervention improved the regional connectivity among the motor areas during both the tasks. The connectivity between PMC and M1 was stronger in motor-imagery tasks whereas the connectivity from PMC to M1, SM A to M1 dominated in motor-execution tasks. There was significant behavioral improvement (p = 0.001) in sensation and motor movements because of the intervention as reflected by behavioral Fugl-Meyer (FMA) measures, which were significantly correlated (p = 0.05) with a subset of connectivity. These findings suggest that PMC and M1 play a crucial role during motor-imagery as well as during motor-execution task. In addition, M1 causes more exchange of causal information among motor areas during a motor-execution task than during a motor-imagery task due to its interaction with SM A. This study expands our understanding of motor network involved during two different tasks, which are commonly used during rehabilitation following stroke. A clear understanding of the effective connectivity networks leads to a better treatment in helping stroke survivors regain motor ability.

Telemanipulator design and optimization software

NASA Astrophysics Data System (ADS)

Cote, Jean; Pelletier, Michel

1995-12-01

For many years, industrial robots have been used to execute specific repetitive tasks. In those cases, the optimal configuration and location of the manipulator only has to be found once. The optimal configuration or position where often found empirically according to the tasks to be performed. In telemanipulation, the nature of the tasks to be executed is much wider and can be very demanding in terms of dexterity and workspace. The position/orientation of the robot's base could be required to move during the execution of a task. At present, the choice of the initial position of the teleoperator is usually found empirically which can be sufficient in the case of an easy or repetitive task. In the converse situation, the amount of time wasted to move the teleoperator support platform has to be taken into account during the execution of the task. Automatic optimization of the position/orientation of the platform or a better designed robot configuration could minimize these movements and save time. This paper will present two algorithms. The first algorithm is used to optimize the position and orientation of a given manipulator (or manipulators) with respect to the environment on which a task has to be executed. The second algorithm is used to optimize the position or the kinematic configuration of a robot. For this purpose, the tasks to be executed are digitized using a position/orientation measurement system and a compact representation based on special octrees. Given a digitized task, the optimal position or Denavit-Hartenberg configuration of the manipulator can be obtained numerically. Constraints on the robot design can also be taken into account. A graphical interface has been designed to facilitate the use of the two optimization algorithms.

Fault-tolerant dynamic task graph scheduling

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

Kurt, Mehmet C.; Krishnamoorthy, Sriram; Agrawal, Kunal

2014-11-16

In this paper, we present an approach to fault tolerant execution of dynamic task graphs scheduled using work stealing. In particular, we focus on selective and localized recovery of tasks in the presence of soft faults. We elicit from the user the basic task graph structure in terms of successor and predecessor relationships. The work stealing-based algorithm to schedule such a task graph is augmented to enable recovery when the data and meta-data associated with a task get corrupted. We use this redundancy, and the knowledge of the task graph structure, to selectively recover from faults with low space andmore » time overheads. We show that the fault tolerant design retains the essential properties of the underlying work stealing-based task scheduling algorithm, and that the fault tolerant execution is asymptotically optimal when task re-execution is taken into account. Experimental evaluation demonstrates the low cost of recovery under various fault scenarios.« less

A Developmental Window into Trade-offs in Executive Function: The Case of Task Switching versus Response Inhibition in 6-year-olds

PubMed Central

Chatham, Christopher H.; Wiseheart, Melody; Munakata, Yuko

2014-01-01

Good executive function has been linked to many positive outcomes in academic performance, health, and social competence. However, some aspects of executive function may interfere with other cognitive processes. Childhood provides a unique test case for investigating such cognitive trade-offs, given the dramatic failures and developments observed during this period. For example, most children categorically switch or perseverate when asked to switch between rules on a card-sorting task. To test potential trade-offs with the development of task switching abilities, we compared 6-year-olds who switched versus perseverated in a card-sorting task on two aspects of inhibitory control: response inhibition (via a stop signal task) and interference control (via a Simon task). Across two studies, switchers showed worse response inhibition than perseverators, consistent with the idea of cognitive trade-offs; however, switchers showed better interference control than perseverators, consistent with prior work documenting benefits associated with the development of executive function. This pattern of positive and negative associations may reflect aspects of working memory (active maintenance of current goals, and clearing of prior goals) that help children focused on a single task-goal but hurt in situations with conflicting goals. Implications for understanding components of executive function and their relationships across development are discussed. PMID:24791710

Smart SPHERES: A Telerobotic Free-Flyer for Intravehicular Activities in Space

NASA Technical Reports Server (NTRS)

Fong, Terrence; Micire, Mark J.; Morse, Ted; Park, Eric; Provencher, Chris; To, Vinh; Wheeler, D. W.; Mittman, David; Torres, R. Jay; Smith, Ernest

2013-01-01

Smart SPHERES is a prototype free-flying space robot based on the SPHERES platform. Smart SPHERES can be remotely operated by astronauts inside a spacecraft, or by mission controllers on the ground. We developed Smart SPHERES to perform a variety of intravehicular activities (IVA), such as operations inside the International Space Station (ISS). These IVA tasks include environmental monitoring surveys (radiation, sound levels, etc.), inventory, and mobile camera work. In this paper, we first discuss the motivation for free-flying space robots. We then describe the development of the Smart SPHERES prototype, including avionics, software, and data communications. Finally, we present results of initial flight tests on-board the ISS.

Robust control of multi-jointed arm with a decentralized autonomous control mechanism

NASA Technical Reports Server (NTRS)

Kimura, Shinichi; Miyazaki, Ken; Suzuki, Yoshiaki

1994-01-01

A decentralized autonomous control mechanism applied to the control of three dimensional manipulators and its robustness to partial damage was assessed by computer simulation. Decentralized control structures are believed to be quite robust to time delay between the operator and the target system. A 10-jointed manipulator based on our control mechanism was able to continue its positioning task in three-dimensional space without revision of the control program, even after some of its joints were damaged. These results suggest that this control mechanism can be effectively applied to space telerobots, which are associated with serious time delay between the operator and the target system, and which cannot be easily repaired after being partially damaged.

Smart SPHERES: A Telerobotic Free-Flyer for Intravehicular Activities in Space

NASA Technical Reports Server (NTRS)

Fong, Terrence; Micire, Mark J.; Morse, Ted; Park, Eric; Provencher, Chris

2013-01-01

Smart SPHERES is a prototype free-flying space robot based on the SPHERES platform. Smart SPHERES can be remotely operated by astronauts inside a spacecraft, or by mission controllers on the ground. We developed Smart SPHERES to perform a variety of intravehicular activities (IVA), such as operations inside the International Space Station (ISS). These IVA tasks include environmental monitoring surveys (radiation, sound levels, etc.), inventory, and mobile camera work. In this paper, we first discuss the motivation for free- flying space robots. We then describe the development of the Smart SPHERES prototype, including avionics, software, and data communications. Finally, we present results of initial flight tests on-board the ISS.

Increasing Optimism Protects Against Pain-Induced Impairment in Task-Shifting Performance.

PubMed

Boselie, Jantine J L M; Vancleef, Linda M G; Peters, Madelon L

2017-04-01

Persistent pain can lead to difficulties in executive task performance. Three core executive functions that are often postulated are inhibition, updating, and shifting. Optimism, the tendency to expect that good things happen in the future, has been shown to protect against pain-induced performance deterioration in executive function updating. This study tested whether this protective effect of a temporary optimistic state by means of a writing and visualization exercise extended to executive function shifting. A 2 (optimism: optimism vs no optimism) × 2 (pain: pain vs no pain) mixed factorial design was conducted. Participants (N = 61) completed a shifting task once with and once without concurrent painful heat stimulation after an optimism or neutral manipulation. Results showed that shifting performance was impaired when experimental heat pain was applied during task execution, and that optimism counteracted pain-induced deterioration in task-shifting performance. Experimentally-induced heat pain impairs shifting task performance and manipulated optimism or induced optimism counteracted this pain-induced performance deterioration. Identifying psychological factors that may diminish the negative effect of persistent pain on the ability to function in daily life is imperative. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

Musical Training, Bilingualism, and Executive Function: A Closer Look at Task Switching and Dual-Task Performance

ERIC Educational Resources Information Center

Moradzadeh, Linda; Blumenthal, Galit; Wiseheart, Melody

2015-01-01

This study investigated whether musical training and bilingualism are associated with enhancements in specific components of executive function, namely, task switching and dual-task performance. Participants (n = 153) belonging to one of four groups (monolingual musician, bilingual musician, bilingual non-musician, or monolingual non-musician)…

Social task switching: On the automatic social engagement of executive functions.

PubMed

Dudarev, Veronica; Hassin, Ran R

2016-01-01

Humans are quintessentially social, yet much of cognitive psychology has focused on the individual, in individual settings. The literature on joint action is one of the most prominent exceptions. Joint-action research studies the sociality of our mental representations by examining how the tasks of other people around us affect our own task performance. In this paper we go beyond examining whether we represent others and their tasks, by asking whether we also automatically do their tasks with them, even if they require effortful executive functions. To this end we examine one of the core executive functions, shifting, in a new paradigm that allows us to investigate task-switching in a joint-action setup. Copyright © 2015 Elsevier B.V. All rights reserved.

The benefits of Tai Chi and brisk walking for cognitive function and fitness in older adults

PubMed Central

Ji, Zhiguang; Feng, Tian; Liu, Xiaolei; You, Yihong; Meng, Fanying; Wang, Ruoqing; Lu, Jialing

2017-01-01

The purpose of this study was to investigate the benefits of exercises with different cognitive demands for cognitive functions (Executive and non-Executive) in healthy older adults. A cross-sectional design was adopted. In total, 84 healthy older adults were enrolled in the study. They were categorized into the Tai Chi group (TG), the brisk walking group (BG) or the control group (CG). Each participant performed the Stroop task and a digit comparison task. The Stroop task included the following three conditions: a naming condition, an inhibition condition and an executive condition. There were two experimental conditions in the digit comparison task: the non-delay condition and the delay condition. The results indicated that participants of the TG and BG revealed significant better performance than the CG in the executive condition of cognitive tasks and fitness. There was no significant difference of reaction time (RT) and accuracy rate in the inhibition and delay conditions of cognitive tasks and fitness between the TG and BG. The TG showed shorter reaction time in the naming and the executive conditions, and more accurate in the inhibition conditions than the BG. These findings demonstrated that regular participation in brisk walking and Tai Chi have significant beneficial effects on executive function and fitness. However, due to the high cognitive demands of the exercise, Tai Chi benefit cognitive functions (Executive and non-Executive) in older adults more than brisk walking does. Further studies should research the underlying mechanisms at the behavioural and neuroelectric levels, providing more evidence to explain the effect of high-cognitive demands exercise on different processing levels of cognition. PMID:29062610

Balanced bilingualism and early age of second language acquisition as the underlying mechanisms of a bilingual executive control advantage: why variations in bilingual experiences matter

PubMed Central

Yow, W. Quin; Li, Xiaoqian

2015-01-01

Recent studies revealed inconsistent evidences of a bilingual advantage in executive processing. One potential source of explanation is the multifaceted experience of the bilinguals in these studies. This study seeks to test whether bilinguals who engage in language selection more frequently would perform better in executive control tasks than those bilinguals who engage in language selection less frequently. We examined the influence of the degree of bilingualism (i.e., language proficiency, frequency of use of two languages, and age of second language acquisition) on executive functioning in bilingual young adults using a comprehensive battery of executive control tasks. Seventy-two 18- to 25-years-old English–Mandarin bilinguals performed four computerized executive function (EF) tasks (Stroop, Eriksen flanker, number–letter switching, and n-back task) that measure the EF components: inhibition, mental-set shifting, and information updating and monitoring. Results from multiple regression analyses, structural equation modeling, and bootstrapping supported the positive association between age of second language acquisition and the interference cost in the Stroop task. Most importantly, we found a significant effect of balanced bilingualism (balanced usage of and balanced proficiency in two languages) on the Stroop and number–letter task (mixing cost only), indicating that a more balanced use and a more balanced level of proficiency in two languages resulted in better executive control skills in the adult bilinguals. We did not find any significant effect of bilingualism on flanker or n-back task. These findings provided important insights to the underlying mechanisms of the bilingual cognitive advantage hypothesis, demonstrating that regular experience with extensive practice in controlling attention to their two language systems results in better performance in related EFs such as inhibiting prepotent responses and global set-shifting. PMID:25767451

Balanced bilingualism and early age of second language acquisition as the underlying mechanisms of a bilingual executive control advantage: why variations in bilingual experiences matter.

PubMed

Yow, W Quin; Li, Xiaoqian

2015-01-01

Recent studies revealed inconsistent evidences of a bilingual advantage in executive processing. One potential source of explanation is the multifaceted experience of the bilinguals in these studies. This study seeks to test whether bilinguals who engage in language selection more frequently would perform better in executive control tasks than those bilinguals who engage in language selection less frequently. We examined the influence of the degree of bilingualism (i.e., language proficiency, frequency of use of two languages, and age of second language acquisition) on executive functioning in bilingual young adults using a comprehensive battery of executive control tasks. Seventy-two 18- to 25-years-old English-Mandarin bilinguals performed four computerized executive function (EF) tasks (Stroop, Eriksen flanker, number-letter switching, and n-back task) that measure the EF components: inhibition, mental-set shifting, and information updating and monitoring. Results from multiple regression analyses, structural equation modeling, and bootstrapping supported the positive association between age of second language acquisition and the interference cost in the Stroop task. Most importantly, we found a significant effect of balanced bilingualism (balanced usage of and balanced proficiency in two languages) on the Stroop and number-letter task (mixing cost only), indicating that a more balanced use and a more balanced level of proficiency in two languages resulted in better executive control skills in the adult bilinguals. We did not find any significant effect of bilingualism on flanker or n-back task. These findings provided important insights to the underlying mechanisms of the bilingual cognitive advantage hypothesis, demonstrating that regular experience with extensive practice in controlling attention to their two language systems results in better performance in related EFs such as inhibiting prepotent responses and global set-shifting.

Executive function deficits in team sport athletes with a history of concussion revealed by a visual-auditory dual task paradigm.

PubMed

Tapper, Anthony; Gonzalez, Dave; Roy, Eric; Niechwiej-Szwedo, Ewa

2017-02-01

The purpose of this study was to examine executive functions in team sport athletes with and without a history of concussion. Executive functions comprise many cognitive processes including, working memory, attention and multi-tasking. Past research has shown that concussions cause difficulties in vestibular-visual and vestibular-auditory dual-tasking, however, visual-auditory tasks have been examined rarely. Twenty-nine intercollegiate varsity ice hockey athletes (age = 19.13, SD = 1.56; 15 females) performed an experimental dual-task paradigm that required simultaneously processing visual and auditory information. A brief interview, event description and self-report questionnaires were used to assign participants to each group (concussion, no-concussion). Eighteen athletes had a history of concussion and 11 had no concussion history. The two tests involved visuospatial working memory (i.e., Corsi block test) and auditory tone discrimination. Participants completed both tasks individually, then simultaneously. Two outcome variables were measured, Corsi block memory span and auditory tone discrimination accuracy. No differences were shown when each task was performed alone; however, athletes with a history of concussion had a significantly worse performance on the tone discrimination task in the dual-task condition. In conclusion, long-term deficits in executive functions were associated with a prior history of concussion when cognitive resources were stressed. Evaluations of executive functions and divided attention appear to be helpful in discriminating participants with and without a history concussion.

Process-based account for the effects of perceptual attention and executive attention on fluid intelligence: an integrative approach.

PubMed

Ren, Xuezhu; Altmeyer, Michael; Reiss, Siegbert; Schweizer, Karl

2013-02-01

Perceptual attention and executive attention represent two higher-order types of attention and associate with distinctly different ways of information processing. It is hypothesized that these two types of attention implicate different cognitive processes, which are assumed to account for the differential effects of perceptual attention and executive attention on fluid intelligence. Specifically, an encoding process is assumed to be crucial in completing the tasks of perceptual attention while two executive processes, updating and shifting, are stimulated in completing the tasks of executive attention. The proposed hypothesis was tested by means of an integrative approach combining experimental manipulations and psychometric modeling. In a sample of 210 participants the encoding process has proven indispensable in completing the tasks of perceptual attention, and this process accounted for a considerable part of fluid intelligence that was assessed by two figural reasoning tests. In contrast, the two executive processes, updating and shifting, turned out to be necessary in performance according to the tasks of executive attention and these processes accounted for a larger part of the variance in fluid intelligence than that of the processes underlying perceptual attention. Copyright © 2012 Elsevier B.V. All rights reserved.

Informing the Structure of Executive Function in Children: A Meta-Analysis of Functional Neuroimaging Data

PubMed Central

McKenna, Róisín; Rushe, T.; Woodcock, Kate A.

2017-01-01

The structure of executive function (EF) has been the focus of much debate for decades. What is more, the complexity and diversity provided by the developmental period only adds to this contention. The development of executive function plays an integral part in the expression of children's behavioral, cognitive, social, and emotional capabilities. Understanding how these processes are constructed during development allows for effective measurement of EF in this population. This meta-analysis aims to contribute to a better understanding of the structure of executive function in children. A coordinate-based meta-analysis was conducted (using BrainMap GingerALE 2.3), which incorporated studies administering functional magnetic resonance imaging (fMRI) during inhibition, switching, and working memory updating tasks in typical children (aged 6–18 years). The neural activation common across all executive tasks was compared to that shared by tasks pertaining only to inhibition, switching or updating, which are commonly considered to be fundamental executive processes. Results support the existence of partially separable but partially overlapping inhibition, switching, and updating executive processes at a neural level, in children over 6 years. Further, the shared neural activation across all tasks (associated with a proposed “unitary” component of executive function) overlapped to different degrees with the activation associated with each individual executive process. These findings provide evidence to support the suggestion that one of the most influential structural models of executive functioning in adults can also be applied to children of this age. However, the findings also call for careful consideration and measurement of both specific executive processes, and unitary executive function in this population. Furthermore, a need is highlighted for a new systematic developmental model, which captures the integrative nature of executive function in children. PMID:28439231

3 CFR 13519 - Executive Order 13519 of November 17, 2009. Establishment of the Financial Fraud Enforcement Task...

Code of Federal Regulations, 2010 CFR

2010-01-01

...; (m) the Federal Housing Finance Agency; (n) the Office of Thrift Supervision; (o) the Office of the... outreach with representatives of financial institutions, corporate entities, nonprofit organizations, State... Corporate Fraud Task Force created by Executive Order 13271 of July 9, 2002. Executive Order 13271 is hereby...

Hyperactivity in boys with attention-deficit/hyperactivity disorder (ADHD): The role of executive and non-executive functions.

PubMed

Hudec, Kristen L; Alderson, R Matt; Patros, Connor H G; Lea, Sarah E; Tarle, Stephanie J; Kasper, Lisa J

2015-01-01

Motor activity of boys (age 8-12 years) with (n=19) and without (n=18) ADHD was objectively measured with actigraphy across experimental conditions that varied with regard to demands on executive functions. Activity exhibited during two n-back (1-back, 2-back) working memory tasks was compared to activity during a choice-reaction time (CRT) task that placed relatively fewer demands on executive processes and during a simple reaction time (SRT) task that required mostly automatic processing with minimal executive demands. Results indicated that children in the ADHD group exhibited greater activity compared to children in the non-ADHD group. Further, both groups exhibited the greatest activity during conditions with high working memory demands, followed by the reaction time and control task conditions, respectively. The findings indicate that large-magnitude increases in motor activity are predominantly associated with increased demands on working memory, though demands on non-executive processes are sufficient to elicit small to moderate increases in motor activity as well. Published by Elsevier Ltd.

Functional Magnetic Resonance Imaging of Working Memory and Executive Dysfunction in Systemic Lupus Erythematosus and Antiphospholipid Antibody-Positive Patients.

PubMed

Kozora, E; Uluğ, A M; Erkan, D; Vo, A; Filley, C M; Ramon, G; Burleson, A; Zimmerman, R; Lockshin, M D

2016-11-01

Standardized cognitive tests and functional magnetic resonance imaging (fMRI) studies of systemic lupus erythematosus (SLE) patients demonstrate deficits in working memory and executive function. These neurobehavioral abnormalities are not well studied in antiphospholipid syndrome, which may occur independently of or together with SLE. This study compares an fMRI paradigm involving motor skills, working memory, and executive function in SLE patients without antiphospholipid antibody (aPL) (the SLE group), aPL-positive non-SLE patients (the aPL-positive group), and controls. Brain MRI, fMRI, and standardized cognitive assessment results were obtained from 20 SLE, 20 aPL-positive, and 10 healthy female subjects with no history of neuropsychiatric abnormality. Analysis of fMRI data showed no differences in performance across groups on bilateral motor tasks. When analysis of variance was used, significant group differences were found in 2 executive function tasks (word generation and word rhyming) and in a working memory task (N-Back). Patients positive for aPL demonstrated higher activation in bilateral frontal, temporal, and parietal cortices compared to controls during working memory and executive function tasks. SLE patients also demonstrated bilateral frontal and temporal activation during working memory and executive function tasks. Compared to controls, both aPL-positive and SLE patients had elevated cortical activation, primarily in the frontal lobes, during tasks involving working memory and executive function. These findings are consistent with cortical overactivation as a compensatory mechanism for early white matter neuropathology in these disorders. © 2016, American College of Rheumatology.

Executive and arousal vigilance decrement in the context of the attentional networks: The ANTI-Vea task.

PubMed

Luna, Fernando Gabriel; Marino, Julián; Roca, Javier; Lupiáñez, Juan

2018-05-20

Vigilance is generally understood as the ability to detect infrequent critical events through long time periods. In tasks like the Sustained Attention to Response Task (SART), participants tend to detect fewer events across time, a phenomenon known as "vigilance decrement". However, vigilance might also involve sustaining a tonic arousal level. In the Psychomotor Vigilance Test (PVT), the vigilance decrement corresponds to an increment across time in both mean and variability of reaction time. The present study aimed to develop a single task -Attentional Networks Test for Interactions and Vigilance - executive and arousal components (ANTI-Vea)- to simultaneously assess both components of vigilance (i.e., the executive vigilance as in the SART, and the arousal vigilance as in the PVT), while measuring the classic attentional functions (phasic alertness, orienting, and executive control). In Experiment #1, the executive vigilance decrement was found as an increment in response bias. In Experiment #2, this result was replicated, and the arousal vigilance decrement was simultaneously observed as an increment in reaction time. The ANTI-Vea solves some issues observed in the previous ANTI-V task with the executive vigilance measure (e.g., a low hit rate and no vigilance decrement). Furthermore, the new ANTI-Vea task assesses both components of vigilance together with others typical attentional functions. The new attentional networks test developed here may be useful to provide a better understanding of the human attentional system. The role of sensitivity and response bias in the executive vigilance decrement are discussed. Copyright © 2018 Elsevier B.V. All rights reserved.

A distributed data acquisition software scheme for the Laboratory Telerobotic Manipulator

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

Butler, P.L.; Glassell, R.L.; Rowe, J.C.

1990-01-01

A custom software architecture was developed for use in the Laboratory Telerobotic Manipulator (LTM) to provide support for the distributed data acquisition electronics. This architecture was designed to provide a comprehensive development environment that proved to be useful for both hardware and software debugging. This paper describes the development environment and the operational characteristics of the real-time data acquisition software. 8 refs., 5 figs.

Real-time qualitative reasoning for telerobotic systems

NASA Technical Reports Server (NTRS)

Pin, Eancois G.

1993-01-01

This paper discusses the sensor-based telerobotic driving of a car in a-priori unknown environments using 'human-like' reasoning schemes implemented on custom-designed VLSI fuzzy inferencing boards. These boards use the Fuzzy Set theoretic framework to allow very vast (30 kHz) processing of full sets of information that are expressed in qualitative form using membership functions. The sensor-based and fuzzy inferencing system was incorporated on an outdoor test-bed platform to investigate two control modes for driving a car on the basis of very sparse and imprecise range data. In the first mode, the car navigates fully autonomously to a goal specified by the operator, while in the second mode, the system acts as a telerobotic driver's aid providing the driver with linguistic (fuzzy) commands to turn left or right, speed up, slow down, stop, or back up depending on the obstacles perceived by the sensors. Indoor and outdoor experiments with both modes of control are described in which the system uses only three acoustic range (sonar) sensor channels to perceive the environment. Sample results are presented that illustrate the feasibility of developing autonomous navigation modules and robust, safety-enhancing driver's aids for telerobotic systems using the new fuzzy inferencing VLSI hardware and 'human-like' reasoning schemes.

Participatory telerobotics

NASA Astrophysics Data System (ADS)

Wissner-Gross, Alexander D.; Sullivan, Timothy M.

2013-05-01

We present a novel "participatory telerobotics" system that generalizes the existing concept of participatory sensing to include real-time teleoperation and telepresence by treating humans with mobile devices as ad-hoc telerobots. In our approach, operators or analysts first choose a desired location for remote surveillance or activity from a live geographic map and are then automatically connected via a coordination server to the nearest available trusted human. That human's device is then activated and begins recording and streaming back to the operator a live audiovisual feed for telepresence, while allowing the operator in turn to request complex teleoperative motions or actions from the human. Supported action requests currently include walking, running, leaning, and turning, all with controllable magnitudes and directions. Compliance with requests is automatically measured and scored in real time by fusing information received from the device's onboard sensors, including its accelerometers, gyroscope, magnetometer, GPS receiver, and cameras. Streams of action requests are visually presented by each device to its human in the form of an augmented reality game that rewards prompt physical compliance while remaining tolerant of network latency. Because of its ability to interactively elicit physical knowledge and operations through ad-hoc collaboration, we anticipate that our participatory telerobotics system will have immediate applications in the intelligence, retail, healthcare, security, and travel industries.

Consolidated fuel reprossing program: The implications of force reflection for teleoperation in space

NASA Technical Reports Server (NTRS)

Draper, John V.; Herndon, Joseph N.; Moore, Wendy E.

1987-01-01

Previous research on teleoperator force feedback is reviewed and results of a testing program which assessed the impact of force reflection on teleoperator task performance are reported. Force relection is a type of force feedback in which the forces acting on the remote portion of the teleoperator are displayed to the operator by back-driving the master controller. The testing program compared three force reflection levels: 4 to 1 (four units of force on the slave produce one unit of force at the master controller), 1 to 1, and infinity to 1 (no force reflection). Time required to complete tasks, rate of occurrence of errors, the maximum force applied to tasks components, and variability in forces applied to components during completion of representative remote handling tasks were used as dependent variables. Operators exhibited lower error rates, lower peak forces, and more consistent application of forces using force relection than they did without it. These data support the hypothesis that force reflection provides useful information for teleoperator users. The earlier literature and the results of the experiment are discussed in terms of their implications for space based teleoperator systems. The discussion described the impact of force reflection on task completion performance and task strategies, as suggested by the literature. It is important to understand the trade-offs involved in using telerobotic systems with and without force reflection.

Executive function assessment in New Zealand 2-year olds born at risk of neonatal hypoglycemia.

PubMed

Ansell, Judith M; Wouldes, Trecia A; Harding, Jane E

2017-01-01

A growing number of babies are born with perinatal risk factors that may impair later development. These children are often assessed at 2 years to help predict outcome and direct support services. Executive function is an important predictor of academic achievement and behavior, but there are limited assessments of executive function in 2-year-olds and few have been tested in at-risk populations. Therefore, we developed a battery of four age-appropriate tasks to assess executive function in 2-year-olds. At 24 months' corrected age 368 children completed tasks assessing attention, inhibition, working memory and cognitive flexibility. Scores on different tasks were weakly correlated, suggesting that they measured separate aspects of executive function, with combined scores for this cohort approximating a normal distribution. Significantly more boys (67%) than girls (57%) were unable to inhibit their behavior on the Snack Delay Task and girls (M = 3.24, SD = 2.4) had higher mean scores than boys (M = 2.7, SD = 2.7) on the Ducks and Buckets Reverse Categorization Task of working memory. Performance was significantly affected by family socioeconomic status. Mean scores were lower on all four individual tasks and on the global score of overall performance in children from a low household income (<$40,000) compared to those from medium ($40,001-$70,000) and high income households (>$70,001). Maternal education was only associated with scores on the working memory task and the global score; and a measure of neighborhood deprivation was only associated with scores on the two inhibitory tasks and the global score. Our findings confirm the feasibility of assessing executive function in 2-year-olds, and its ability to discriminate effects of socioeconomic status, a common confounder in child development research. Further development and standardization of this test battery comparing at-risk children with a normative population would provide a much-needed measure of executive function in early childhood.

Executive function assessment in New Zealand 2-year olds born at risk of neonatal hypoglycemia

PubMed Central

2017-01-01

A growing number of babies are born with perinatal risk factors that may impair later development. These children are often assessed at 2 years to help predict outcome and direct support services. Executive function is an important predictor of academic achievement and behavior, but there are limited assessments of executive function in 2-year-olds and few have been tested in at-risk populations. Therefore, we developed a battery of four age-appropriate tasks to assess executive function in 2-year-olds. At 24 months’ corrected age 368 children completed tasks assessing attention, inhibition, working memory and cognitive flexibility. Scores on different tasks were weakly correlated, suggesting that they measured separate aspects of executive function, with combined scores for this cohort approximating a normal distribution. Significantly more boys (67%) than girls (57%) were unable to inhibit their behavior on the Snack Delay Task and girls (M = 3.24, SD = 2.4) had higher mean scores than boys (M = 2.7, SD = 2.7) on the Ducks and Buckets Reverse Categorization Task of working memory. Performance was significantly affected by family socioeconomic status. Mean scores were lower on all four individual tasks and on the global score of overall performance in children from a low household income (<$40,000) compared to those from medium ($40,001-$70,000) and high income households (>$70,001). Maternal education was only associated with scores on the working memory task and the global score; and a measure of neighborhood deprivation was only associated with scores on the two inhibitory tasks and the global score. Our findings confirm the feasibility of assessing executive function in 2-year-olds, and its ability to discriminate effects of socioeconomic status, a common confounder in child development research. Further development and standardization of this test battery comparing at-risk children with a normative population would provide a much-needed measure of executive function in early childhood. PMID:29166407

Post-traumatic stress disorder is associated with limited executive resources in a working memory task

PubMed Central

Honzel, Nikki; Justus, Timothy; Swick, Diane

2015-01-01

Patients with post-traumatic stress disorder (PTSD) can show declines in working memory. A dual-task design was used to determine if these impairments are linked to executive control limitations. Participants performed a Sternberg memory task with either one or four letters. In the dual-task condition, the maintenance period was filled with an arrow flanker task. PTSD patients were less accurate on the working memory task than controls, especially in the dual-task condition. In the single-task condition, both groups showed similar patterns of brain potentials from 300–500 ms when discriminating old and new probes. However, when taxed with an additional task, the event-related potentials (ERPs) of the PTSD group no longer differentiated old and new probes. In contrast, interference resolution processes in both the single- and dual-task conditions of the flanker were intact. The lack of differentiation in the ERPs reflects impaired working memory performance under more difficult dual-task conditions. Exacerbated difficulty in performing a working memory task with concurrent task demands suggests a specific limitation in executive control resources in PTSD. PMID:24165904

A Multitasking General Executive for Compound Continuous Tasks

ERIC Educational Resources Information Center

Salvucci, Dario D.

2005-01-01

As cognitive architectures move to account for increasingly complex real-world tasks, one of the most pressing challenges involves understanding and modeling human multitasking. Although a number of existing models now perform multitasking in real-world scenarios, these models typically employ customized executives that schedule tasks for the…

Task feedback effects on conflict monitoring and executive control: relationship to subclinical measures of depression.

PubMed

Holmes, Avram J; Pizzagalli, Diego A

2007-02-01

Emerging evidence suggests that depression is associated with executive dysfunction, particularly after committing errors or receiving negative performance feedback. To test this hypothesis, 57 participants performed two executive tasks known to elicit errors (the Simon and Stroop Tasks) during positive or negative performance feedback. Participants with elevated depressive symptoms (Beck Depression Inventory scores >or= 13) were characterized by impaired posterror and postconflict performance adjustments, especially during emotionally negative task-related feedback. Additionally, for both tasks, depressive symptoms were inversely related to postconflict reaction time adjustments following negative, but not positive, feedback. These findings suggest that subclinical depression is associated with impairments in behavioral adjustments after internal (perceived failure) and external feedback about deficient task performance. (c) 2007 APA, all rights reserved.

Age-related differences in listening effort during degraded speech recognition

PubMed Central

Ward, Kristina M.; Shen, Jing; Souza, Pamela E.; Grieco-Calub, Tina M.

2016-01-01

Objectives The purpose of the current study was to quantify age-related differences in executive control as it relates to dual-task performance, which is thought to represent listening effort, during degraded speech recognition. Design Twenty-five younger adults (18–24 years) and twenty-one older adults (56–82 years) completed a dual-task paradigm that consisted of a primary speech recognition task and a secondary visual monitoring task. Sentence material in the primary task was either unprocessed or spectrally degraded into 8, 6, or 4 spectral channels using noise-band vocoding. Performance on the visual monitoring task was assessed by the accuracy and reaction time of participants’ responses. Performance on the primary and secondary task was quantified in isolation (i.e., single task) and during the dual-task paradigm. Participants also completed a standardized psychometric measure of executive control, including attention and inhibition. Statistical analyses were implemented to evaluate changes in listeners’ performance on the primary and secondary tasks (1) per condition (unprocessed vs. vocoded conditions); (2) per task (baseline vs. dual task); and (3) per group (younger vs. older adults). Results Speech recognition declined with increasing spectral degradation for both younger and older adults when they performed the task in isolation or concurrently with the visual monitoring task. Older adults were slower and less accurate than younger adults on the visual monitoring task when performed in isolation, which paralleled age-related differences in standardized scores of executive control. When compared to single-task performance, older adults experienced greater declines in secondary-task accuracy, but not reaction time, than younger adults. Furthermore, results revealed that age-related differences in executive control significantly contributed to age-related differences on the visual monitoring task during the dual-task paradigm. Conclusions Older adults experienced significantly greater declines in secondary-task accuracy during degraded speech recognition than younger adults. These findings are interpreted as suggesting that older listeners expended greater listening effort than younger listeners, and may be partially attributed to age-related differences in executive control. PMID:27556526

[Executive dysfunction in attention deficit hyperactivity disorder in childhood].

PubMed

Romero-Ayuso, D M; Maestú, F; González-Marqués, J; Romo-Barrientos, C; Andrade, J M

The principal problem of ADHD is the difficulty to execute inhibitory control. The inhibition is an executive function that is develop during childhood. To know if other executive functions shower a lower performance in ADHD versus control group and these were different between ADHD-I and ADHD-C. Fifty three children, between 7 to 10 years old, participated and were assess with EMIC and Simon task. The results showed similar profile in working memory and verbal span. In contrast, ADHD-C showed lower performance in Simon task and more impulsively. On an other hand, ADHD-I showed lower performance in memory working tasks and planning. These results suggest differences in the executive profile between ADHD-I and ADHD-C and these support the hypothesis of Barkley about the necessity to differ both clinical subtypes.

Symbiosis of executive and selective attention in working memory

PubMed Central

Vandierendonck, André

2014-01-01

The notion of working memory (WM) was introduced to account for the usage of short-term memory resources by other cognitive tasks such as reasoning, mental arithmetic, language comprehension, and many others. This collaboration between memory and other cognitive tasks can only be achieved by a dedicated WM system that controls task coordination. To that end, WM models include executive control. Nevertheless, other attention control systems may be involved in coordination of memory and cognitive tasks calling on memory resources. The present paper briefly reviews the evidence concerning the role of selective attention in WM activities. A model is proposed in which selective attention control is directly linked to the executive control part of the WM system. The model assumes that apart from storage of declarative information, the system also includes an executive WM module that represents the current task set. Control processes are automatically triggered when particular conditions in these modules are met. As each task set represents the parameter settings and the actions needed to achieve the task goal, it will depend on the specific settings and actions whether selective attention control will have to be shared among the active tasks. Only when such sharing is required, task performance will be affected by the capacity limits of the control system involved. PMID:25152723

Symbiosis of executive and selective attention in working memory.

PubMed

Vandierendonck, André

2014-01-01

The notion of working memory (WM) was introduced to account for the usage of short-term memory resources by other cognitive tasks such as reasoning, mental arithmetic, language comprehension, and many others. This collaboration between memory and other cognitive tasks can only be achieved by a dedicated WM system that controls task coordination. To that end, WM models include executive control. Nevertheless, other attention control systems may be involved in coordination of memory and cognitive tasks calling on memory resources. The present paper briefly reviews the evidence concerning the role of selective attention in WM activities. A model is proposed in which selective attention control is directly linked to the executive control part of the WM system. The model assumes that apart from storage of declarative information, the system also includes an executive WM module that represents the current task set. Control processes are automatically triggered when particular conditions in these modules are met. As each task set represents the parameter settings and the actions needed to achieve the task goal, it will depend on the specific settings and actions whether selective attention control will have to be shared among the active tasks. Only when such sharing is required, task performance will be affected by the capacity limits of the control system involved.

Executive functioning and visual working memory.

PubMed

Lepach, Anja C; Pauls, Franz; Petermann, Franz

2015-01-01

The matter of modality is controversially discussed in the context of working memory (WM). There is evidence that modality-specific processes are accompanied by amodal processes to some extent. We investigated the relationship between executive-functioning tasks and visual WM (VWM) and were especially interested in the issue of amodal processes. Our correlational analyses suggest modality-independent relations of the tasks. We also aimed to quantify to what extent executive functioning is meaningful for VWM performances. We therefore estimated the relationship between executive tasks and VWM performances in a healthy (n = 710) and a clinical traumatic brain injury sample (n = 151) as well as in the combined total sample. The results indicate a substantial relevance of the verbal task for VWM performances in the total and the clinical sample but a low relevance in the healthy sample. These results could support assumptions of resource-depending differences in the relations of executive functioning and VWM but need further validation due to limitations of our study.

[Executive dysfunctions in adults with attention deficit hyperactivity disorder].

PubMed

Rodriguez-Jiménez, R; Cubillo, A; Jiménez-Arriero, M A; Ponce, G; Aragüés-Figuero, M; Palomo, T

Several different follow-up studies have shown that attention deficit hyperactivity disorder (ADHD) can persist into adulthood. To review the findings in adults with ADHD related to alterations in the executive functions. Research conducted among children with ADHD has revealed the existence of alterations in different tasks that evaluate the executive functions, such as the planning test, sustained attention tasks, cognitive flexibility, verbal fluency and working memory tasks, as well as several inhibition response tasks. In adults with ADHD, despite the lower number of reports in the literature and the methodological shortcomings that exist in some studies, analogous results have also been described with respect to executive functioning, namely, disorders affecting inhibition response, the capacity for planning, difficulties in cognitive flexibility and verbal fluency, and problems with working memory, which include aspects of spatial working memory, logical or visual memory. The findings we have available at present enable us to confirm the persistence of executive dysfunctions in adult patients with ADHD that are similar to those observed in children with ADHD.

Brain effective connectivity during motor-imagery and execution following stroke and rehabilitation

PubMed Central

Bajaj, Sahil; Butler, Andrew J.; Drake, Daniel; Dhamala, Mukesh

2015-01-01

Brain areas within the motor system interact directly or indirectly during motor-imagery and motor-execution tasks. These interactions and their functionality can change following stroke and recovery. How brain network interactions reorganize and recover their functionality during recovery and treatment following stroke are not well understood. To contribute to answering these questions, we recorded blood oxygenation-level dependent (BOLD) functional magnetic resonance imaging (fMRI) signals from 10 stroke survivors and evaluated dynamical causal modeling (DCM)-based effective connectivity among three motor areas: primary motor cortex (M1), pre-motor cortex (PMC) and supplementary motor area (SMA), during motor-imagery and motor-execution tasks. We compared the connectivity between affected and unaffected hemispheres before and after mental practice and combined mental practice and physical therapy as treatments. The treatment (intervention) period varied in length between 14 to 51 days but all patients received the same dose of 60 h of treatment. Using Bayesian model selection (BMS) approach in the DCM approach, we found that, after intervention, the same network dominated during motor-imagery and motor-execution tasks but modulatory parameters suggested a suppressive influence of SM A on M1 during the motor-imagery task whereas the influence of SM A on M1 was unrestricted during the motor-execution task. We found that the intervention caused a reorganization of the network during both tasks for unaffected as well as for the affected hemisphere. Using Bayesian model averaging (BMA) approach, we found that the intervention improved the regional connectivity among the motor areas during both the tasks. The connectivity between PMC and M1 was stronger in motor-imagery tasks whereas the connectivity from PMC to M1, SM A to M1 dominated in motor-execution tasks. There was significant behavioral improvement (p = 0.001) in sensation and motor movements because of the intervention as reflected by behavioral Fugl-Meyer (FMA) measures, which were significantly correlated (p = 0.05) with a subset of connectivity. These findings suggest that PMC and M1 play a crucial role during motor-imagery as well as during motor-execution task. In addition, M1 causes more exchange of causal information among motor areas during a motor-execution task than during a motor-imagery task due to its interaction with SM A. This study expands our understanding of motor network involved during two different tasks, which are commonly used during rehabilitation following stroke. A clear understanding of the effective connectivity networks leads to a better treatment in helping stroke survivors regain motor ability. PMID:26236627

Calculation and word problem-solving skills in primary grades - Impact of cognitive abilities and longitudinal interrelations with task-persistent behaviour.

PubMed

Jõgi, Anna-Liisa; Kikas, Eve

2016-06-01

Primary school math skills form a basis for academic success down the road. Different math skills have different antecedents and there is a reason to believe that more complex math tasks require better self-regulation. The study aimed to investigate longitudinal interrelations of calculation and problem-solving skills, and task-persistent behaviour in Grade 1 and Grade 3, and the effect of non-verbal intelligence, linguistic abilities, and executive functioning on math skills and task persistence. Participants were 864 students (52.3% boys) from 33 different schools in Estonia. Students were tested twice - at the end of Grade1 and at the end of Grade 3. Calculation and problem-solving skills, and teacher-rated task-persistent behaviour were measured at both time points. Non-verbal intelligence, linguistic abilities, and executive functioning were measured in Grade 1. Cross-lagged structural equation modelling indicated that calculation skills depend on previous math skills and linguistic abilities, while problem-solving skills require also non-verbal intelligence, executive functioning, and task persistence. Task-persistent behaviour in Grade 3 was predicted by previous problem-solving skills, linguistic abilities, and executive functioning. Gender and mother's educational level were added as covariates. The findings indicate that math skills and self-regulation are strongly related in primary grades and that solving complex tasks requires executive functioning and task persistence from children. Findings support the idea that instructional practices might benefit from supporting self-regulation in order to gain domain-specific, complex skill achievement. © 2015 The British Psychological Society.

Two criteria for the selection of assembly plans - Maximizing the flexibility of sequencing the assembly tasks and minimizing the assembly time through parallel execution of assembly tasks

NASA Technical Reports Server (NTRS)

Homem De Mello, Luiz S.; Sanderson, Arthur C.

1991-01-01

The authors introduce two criteria for the evaluation and selection of assembly plans. The first criterion is to maximize the number of different sequences in which the assembly tasks can be executed. The second criterion is to minimize the total assembly time through simultaneous execution of assembly tasks. An algorithm that performs a heuristic search for the best assembly plan over the AND/OR graph representation of assembly plans is discussed. Admissible heuristics for each of the two criteria introduced are presented. Some implementation issues that affect the computational efficiency are addressed.

The Role of Executive Functions in the Control of Aggressive Behavior

PubMed Central

Krämer, Ulrike M.; Kopyciok, Robert P. J.; Richter, Sylvia; Rodriguez-Fornells, Antoni; Münte, Thomas F.

2011-01-01

An extensive literature suggests a link between executive functions and aggressive behavior in humans, pointing mostly to an inverse relationship, i.e., increased tendencies toward aggression in individuals scoring low on executive function tests. This literature is limited, though, in terms of the groups studied and the measures of executive functions. In this paper, we present data from two studies addressing these issues. In a first behavioral study, we asked whether high trait aggressiveness is related to reduced executive functions. A sample of over 600 students performed in an extensive behavioral test battery including paradigms addressing executive functions such as the Eriksen Flanker task, Stroop task, n-back task, and Tower of London (TOL). High trait aggressive participants were found to have a significantly reduced latency score in the TOL, indicating more impulsive behavior compared to low trait aggressive participants. No other differences were detected. In an EEG-study, we assessed neural and behavioral correlates of error monitoring and response inhibition in participants who were characterized based on their laboratory-induced aggressive behavior in a competitive reaction time task. Participants who retaliated more in the aggression paradigm and had reduced frontal activity when being provoked did not, however, show any reduction in behavioral or neural correlates of executive control compared to the less aggressive participants. Our results question a strong relationship between aggression and executive functions at least for healthy, high-functioning people. PMID:21747775

Investigating executive functions in children with severe speech and movement disorders using structured tasks.

PubMed

Stadskleiv, Kristine; von Tetzchner, Stephen; Batorowicz, Beata; van Balkom, Hans; Dahlgren-Sandberg, Annika; Renner, Gregor

2014-01-01

Executive functions are the basis for goal-directed activity and include planning, monitoring, and inhibition, and language seems to play a role in the development of these functions. There is a tradition of studying executive function in both typical and atypical populations, and the present study investigates executive functions in children with severe speech and motor impairments who are communicating using communication aids with graphic symbols, letters, and/or words. There are few neuropsychological studies of children in this group and little is known about their cognitive functioning, including executive functions. It was hypothesized that aided communication would tax executive functions more than speech. Twenty-nine children using communication aids and 27 naturally speaking children participated. Structured tasks resembling everyday activities, where the action goals had to be reached through communication with a partner, were used to get information about executive functions. The children (a) directed the partner to perform actions like building a Lego tower from a model the partner could not see and (b) gave information about an object without naming it to a person who had to guess what object it was. The executive functions of planning, monitoring, and impulse control were coded from the children's on-task behavior. Both groups solved most of the tasks correctly, indicating that aided communicators are able to use language to direct another person to do a complex set of actions. Planning and lack of impulsivity was positively related to task success in both groups. The aided group completed significantly fewer tasks, spent longer time and showed more variation in performance than the comparison group. The aided communicators scored lower on planning and showed more impulsivity than the comparison group, while both groups showed an equal degree of monitoring of the work progress. The results are consistent with the hypothesis that aided language tax executive functions more than speech. The results may also indicate that aided communicators have less experience with these kinds of play activities. The findings broaden the perspective on executive functions and have implications for interventions for motor-impaired children developing aided communication.

Investigating executive functions in children with severe speech and movement disorders using structured tasks

PubMed Central

Stadskleiv, Kristine; von Tetzchner, Stephen; Batorowicz, Beata; van Balkom, Hans; Dahlgren-Sandberg, Annika; Renner, Gregor

2014-01-01

Executive functions are the basis for goal-directed activity and include planning, monitoring, and inhibition, and language seems to play a role in the development of these functions. There is a tradition of studying executive function in both typical and atypical populations, and the present study investigates executive functions in children with severe speech and motor impairments who are communicating using communication aids with graphic symbols, letters, and/or words. There are few neuropsychological studies of children in this group and little is known about their cognitive functioning, including executive functions. It was hypothesized that aided communication would tax executive functions more than speech. Twenty-nine children using communication aids and 27 naturally speaking children participated. Structured tasks resembling everyday activities, where the action goals had to be reached through communication with a partner, were used to get information about executive functions. The children (a) directed the partner to perform actions like building a Lego tower from a model the partner could not see and (b) gave information about an object without naming it to a person who had to guess what object it was. The executive functions of planning, monitoring, and impulse control were coded from the children's on-task behavior. Both groups solved most of the tasks correctly, indicating that aided communicators are able to use language to direct another person to do a complex set of actions. Planning and lack of impulsivity was positively related to task success in both groups. The aided group completed significantly fewer tasks, spent longer time and showed more variation in performance than the comparison group. The aided communicators scored lower on planning and showed more impulsivity than the comparison group, while both groups showed an equal degree of monitoring of the work progress. The results are consistent with the hypothesis that aided language tax executive functions more than speech. The results may also indicate that aided communicators have less experience with these kinds of play activities. The findings broaden the perspective on executive functions and have implications for interventions for motor-impaired children developing aided communication. PMID:25249999

Performances on a cognitive theory of mind task: specific decline or general cognitive deficits? Evidence from normal aging.

PubMed

Fliss, Rafika; Lemerre, Marion; Mollard, Audrey

2016-06-01

Compromised theory of mind (ToM) can be explained either by a failure to implement specific representational capacities (mental state representations) or by more general executive selection demands. In older adult populations, evidence supporting affected executive functioning and cognitive ToM in normal aging are reported. However, links between these two functions remain unclear. In the present paper, we address these shortcomings by using a specific task of ToM and classical executive tasks. We studied, using an original cognitive ToM task, the effect of age on ToM performances, in link with the progressive executive decline. 96 elderly participants were recruited. They were asked to perform a cognitive ToM task, and 5 executive tests (Stroop test and Hayling Sentence Completion Test to appreciate inhibitory process, Trail Making Test and Verbal Fluency for shifting assessment and backward span dedicated to estimate working memory capacity). The results show changes in cognitive ToM performance according to executive demands. Correlational studies indicate a significant relationship between ToM performance and the selected executive measures. Regression analyzes demonstrates that level of vocabulary and age as the best predictors of ToM performance. The results are consistent with the hypothesis that ToM deficits are related to age-related domain-general decline rather than as to a breakdown in specialized representational system. The implications of these findings for the nature of social cognition tests in normal aging are also discussed.

Evidence that specific executive functions predict symptom variance among schizophrenia patients with a predominantly negative symptom profile.

PubMed

Donohoe, Gary; Corvin, Aiden; Robertson, Ian H

2006-01-01

Although deficits in executive functioning in schizophrenia have been consistently reported, their precise relationship to symptomatology remains unclear. Recent approaches to executive functioning in nonschizophrenia studies have aimed to "fractionate" the individual cognitive processes involved. In this study, we hypothesised that if these processes are fractionable, then particular symptom syndromes may be selectively related to executive deficits. In particular, it was hoped that this approach could clarify whether negative and positive symptoms of schizophrenia are differentially related to particular aspects of executive/attentional functions. A total of 32 patients with schizophrenia and 16 matched controls were assessed on a series of tasks designed to tap the theoretically derived executive functions of Inhibition, Shifting set, Working memory, and Sustained attention. Negative symptoms were significantly predicted by performance on an "Inhibition" task (Stroop), and not by performance on any other task. Furthermore, for a subgroup of patients with predominantly negative symptoms variance in positive symptoms was only significantly predicted by performance on a set-shifting task (Visual Elevator), and not by performance on other tasks, including inhibition. Our results support the contention that negative symptoms can, at least partly, be conceived of as cognitive behaviours expressing specific executive deficits. Specifically, we discuss the possibility that negative symptoms may, in part, express a failure in response monitoring. We further suggest that the disordered metacognition resulting in positive symptoms may be mediated by cognitive flexibility in patients with a predominantly negative symptom profile.

Supervisory manipulation based on the concepts of absolute vs relative and fixed vs moving tasks

NASA Technical Reports Server (NTRS)

Brooks, T. L.

1980-01-01

If a machine is to perform a given subtask autonomously, it will require an internal model which, combined with operator and environmental inputs, can be used to generate the manipulator functions necessary to complete the task. This paper will advance a technique based on linear transformations by which short, supervised periods of manipulation can be accomplished. To achieve this end a distinction will be made between tasks which can be completely defined during the training period, and tasks which can be only partially defined prior to the moment of execution. A further distinction will be made between tasks which have a fixed relationship to the manipulator base throughout the execution period, and tasks which have a continuously changing task/base relationship during execution. Finally, through a rudimentary analysis of the methods developed in this paper, some of the practical aspects of implementing a supervisory system will be illustrated

A smart telerobotic system driven by monocular vision

NASA Technical Reports Server (NTRS)

Defigueiredo, R. J. P.; Maccato, A.; Wlczek, P.; Denney, B.; Scheerer, J.

1994-01-01

A robotic system that accepts autonomously generated motion and control commands is described. The system provides images from the monocular vision of a camera mounted on a robot's end effector, eliminating the need for traditional guidance targets that must be predetermined and specifically identified. The telerobotic vision system presents different views of the targeted object relative to the camera, based on a single camera image and knowledge of the target's solid geometry.

Automation and robotics for Space Station in the twenty-first century

NASA Technical Reports Server (NTRS)

Willshire, K. F.; Pivirotto, D. L.

1986-01-01

Space Station telerobotics will evolve beyond the initial capability into a smarter and more capable system as we enter the twenty-first century. Current technology programs including several proposed ground and flight experiments to enable development of this system are described. Advancements in the areas of machine vision, smart sensors, advanced control architecture, manipulator joint design, end effector design, and artificial intelligence will provide increasingly more autonomous telerobotic systems.

Prevalence of executive dysfunction in cocaine, heroin and alcohol users enrolled in therapeutic communities.

PubMed

Fernández-Serrano, María José; Pérez-García, Miguel; Perales, José C; Verdejo-García, Antonio

2010-01-10

Many studies have observed relevant executive alterations in polysubstance users but no data have been generated in terms of prevalence of these alterations. Studies of the prevalence of neuropsychological impairment can be useful in the design and implementations of interventional programs for substance abusers. The present study was conducted to estimate the prevalence of neuropsychological impairment in different components of executive functions in polysubstance users enrolled in therapeutic communities. Moreover, we estimated the effect size of the differences in the executive performance between polysubstance users and non substance users in order to know which neuropsychological tasks can be useful to detect alterations in the executive functions. Study results showed a high prevalence of executive function impairment in polysubstance users. Working memory was the component with the highest impairment proportion, followed by fluency, shifting, planning, multi-tasking and interference. Comparisons between user groups showed very similar executive impairment prevalence for all the analyzed executive components. The best discriminating task between users and controls was Arithmetic (Wechsler Adult Intelligence Scale, WAIS-III). Moreover FAS and Ruff Figural Fluency Test was discriminating for fluency, Category Test for shifting, Stroop Colour-Word Interference Test for interference, Zoo Map (Behavioural Assessment of the Dysexecutive Syndrome, BADS) for planning and Six Elements (BADS) for multi-tasking. The existence of significant prevalence of executive impairment in polysubstance users reveals the need to redirect the actuation policies in the field of drug-dependency towards the creation of treatments addressed at the executive deficits of the participants, which in turn would facilitate the individuals' compliance and final rehabilitation.

Components of Executive Control with Advantages for Bilingual Children in Two Cultures

ERIC Educational Resources Information Center

Bialystok, Ellen; Viswanathan, Mythili

2009-01-01

The present study used a behavioral version of an anti-saccade task, called the "faces task", developed by [Bialystok, E., Craik, F. I. M., & Ryan, J. (2006). Executive control in a modified anti-saccade task: Effects of aging and bilingualism. "Journal of Experimental Psychology: Learning, Memory, and Cognition," 32,…

Bilingual Advantage in Attentional Control: Evidence from the Forced-Attention Dichotic Listening Paradigm

ERIC Educational Resources Information Center

Soveri, Anna; Laine, Matti; Hamalainen, Heikki; Hugdahl, Kenneth

2011-01-01

It has been claimed that due to their experience in controlling two languages, bilinguals exceed monolinguals in certain executive functions, especially inhibition of task-irrelevant stimuli. Here we investigated the effects of bilingualism on an executive phonological task, namely the forced-attention dichotic listening task with syllabic…

Role of optimization in the human dynamics of task execution

NASA Astrophysics Data System (ADS)

Cajueiro, Daniel O.; Maldonado, Wilfredo L.

2008-03-01

In order to explain the empirical evidence that the dynamics of human activity may not be well modeled by Poisson processes, a model based on queuing processes was built in the literature [A. L. Barabasi, Nature (London) 435, 207 (2005)]. The main assumption behind that model is that people execute their tasks based on a protocol that first executes the high priority item. In this context, the purpose of this paper is to analyze the validity of that hypothesis assuming that people are rational agents that make their decisions in order to minimize the cost of keeping nonexecuted tasks on the list. Therefore, we build and analytically solve a dynamic programming model with two priority types of tasks and show that the validity of this hypothesis depends strongly on the structure of the instantaneous costs that a person has to face if a given task is kept on the list for more than one period. Moreover, one interesting finding is that in one of the situations the protocol used to execute the tasks generates complex one-dimensional dynamics.

Interactions of age and cognitive functions in predicting decision making under risky conditions over the life span.

PubMed

Brand, Matthias; Schiebener, Johannes

2013-01-01

Little is known about how normal healthy aging affects decision-making competence. In this study 538 participants (age 18-80 years) performed the Game of Dice Task (GDT). Subsamples also performed the Iowa Gambling Task as well as tasks measuring logical thinking and executive functions. In a moderated regression analysis, the significant interaction between age and executive components indicates that older participants with good executive functioning perform well on the GDT, while older participants with reduced executive functions make more risky choices. The same pattern emerges for the interaction of age and logical thinking. Results demonstrate that age and cognitive functions act in concert in predicting the decision-making performance.

Executive and attentional functions in chronic pain: Does performance decrease with increasing task load?

PubMed Central

Oosterman, Joukje M; Derksen, Laura C; van Wijck, Albert JM; Kessels, Roy PC; Veldhuijzen, Dieuwke S

2012-01-01

BACKGROUND: Diminished executive function and attentional control has been reported in chronic pain patients. However, the precise pattern of impairment in these aspects of cognition in chronic pain remains unclear. Moreover, a decline in psychomotor speed could potentially influence executive and attentional control performance in pain patients. OBJECTIVE: To examine different aspects of executive and attentional control in chronic pain together with the confounding role of psychomotor slowing. METHODS: Neuropsychological tests of sustained attention, planning ability, inhibition and mental flexibility were administered to 34 participants with chronic pain and 32 control participants. RESULTS: Compared with the controls, participants with chronic pain took longer to complete tests of sustained attention and mental flexibility, but did not perform worse on inhibition or planning tasks. The decreased performance on the mental flexibility task likely reflects a reduction in psychomotor speed. The pattern of performance on the sustained attention task reveals a specific decline in attention, indicated by a disproportionate decline in performance with an increase in task duration and by increased fluctuations in attention during task performance. No additional effect was noted of pain intensity, pain duration, pain catastrophizing, depressive symptoms, reduced sleep because of the pain or opioid use. CONCLUSIONS: Executive and attention functions are not uniformly affected in chronic pain. At least part of the previously reported decline in executive function in this group may reflect psychomotor slowing. Overall, limited evidence was found that executive and attention performance is indeed lower in chronic pain. Therefore, it can be concluded that in chronic pain sustained attention performance is diminished while mental flexibility, planning and inhibition appear to be intact. PMID:22606680

Automatic-heuristic and executive-analytic processing during reasoning: Chronometric and dual-task considerations.

PubMed

De Neys, Wim

2006-06-01

Human reasoning has been shown to overly rely on intuitive, heuristic processing instead of a more demanding analytic inference process. Four experiments tested the central claim of current dual-process theories that analytic operations involve time-consuming executive processing whereas the heuristic system would operate automatically. Participants solved conjunction fallacy problems and indicative and deontic selection tasks. Experiment 1 established that making correct analytic inferences demanded more processing time than did making heuristic inferences. Experiment 2 showed that burdening the executive resources with an attention-demanding secondary task decreased correct, analytic responding and boosted the rate of conjunction fallacies and indicative matching card selections. Results were replicated in Experiments 3 and 4 with a different secondary-task procedure. Involvement of executive resources for the deontic selection task was less clear. Findings validate basic processing assumptions of the dual-process framework and complete the correlational research programme of K. E. Stanovich and R. F. West (2000).

Early stage second-language learning improves executive control: evidence from ERP.

PubMed

Sullivan, Margot D; Janus, Monika; Moreno, Sylvain; Astheimer, Lori; Bialystok, Ellen

2014-12-01

A growing body of research has reported a bilingual advantage in performance on executive control tasks, but it is not known at what point in emerging bilingualism these advantages first appear. The present study investigated the effect of early stage second-language training on executive control. Monolingual English-speaking students were tested on a go-nogo task, sentence judgment task, and verbal fluency, before and after 6 months of Spanish instruction. The training group (n = 25) consisted of students enrolled in introductory Spanish and the control group (n = 30) consisted of students enrolled in introductory Psychology. After training, the Spanish group showed larger P3 amplitude on the go-nogo task and smaller P600 amplitude on the judgment task, indicating enhanced performance, with no changes for the control group and no differences between groups on behavioral measures. Results are discussed in terms of neural changes underlying executive control after brief second-language learning. Copyright © 2014 Elsevier Inc. All rights reserved.

Resisting attraction: Individual differences in executive control are associated with subject-verb agreement errors in production.

PubMed

Veenstra, Alma; Antoniou, Kyriakos; Katsos, Napoleon; Kissine, Mikhail

2018-04-19

We propose that attraction errors in agreement production (e.g., the key to the cabinets are missing) are related to two components of executive control: working memory and inhibitory control. We tested 138 children aged 10 to 12, an age when children are expected to produce high rates of errors. To increase the potential of individual variation in executive control skills, participants came from monolingual, bilingual, and bidialectal language backgrounds. Attraction errors were elicited with a picture description task in Dutch and executive control was measured with a digit span task, Corsi blocks task, switching task, and attentional networks task. Overall, higher rates of attraction errors were negatively associated with higher verbal working memory and, independently, with higher inhibitory control. To our knowledge, this is the first demonstration of the role of both working memory and inhibitory control in attraction errors in production. Implications for memory- and grammar-based models are discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

The effects of bilingual growth on toddlers’ executive function

PubMed Central

Crivello, Cristina; Kuzyk, Olivia; Rodrigues, Monyka; Friend, Margaret; Zesiger, Pascal; Poulin-Dubois, Diane

2015-01-01

The mastery of two languages provides bilingual speakers with cognitive benefits over monolinguals, particularly on cognitive flexibility and selective attention. However, extant research is limited to comparisons between monolinguals and bilinguals at a single point in time. This study investigated whether growth in bilingual proficiency, as shown by an increased number of translation equivalents (TEs) over a 7-month period, improves executive function. We hypothesized that bilingual toddlers with a larger increase of TEs would have more practice in switching across lexical systems, boosting executive function abilities. Expressive vocabulary and TEs were assessed at 24 and 31 months of age. A battery of tasks, including conflict, delay, and working memory tasks, was administered at 31 months. As expected, we observed a task-specific advantage in inhibitory control in bilinguals. More important, within the bilingual group, larger increases in the number of TEs predicted better performance on conflict tasks but not on delay tasks. This unique longitudinal design confirms the relation between executive function and early bilingualism. PMID:26402219

Task-Related Modulations of BOLD Low-Frequency Fluctuations within the Default Mode Network

PubMed Central

Tommasin, Silvia; Mascali, Daniele; Gili, Tommaso; Assan, Ibrahim Eid; Moraschi, Marta; Fratini, Michela; Wise, Richard G.; Macaluso, Emiliano; Mangia, Silvia; Giove, Federico

2017-01-01

Spontaneous low-frequency Blood-Oxygenation Level-Dependent (BOLD) signals acquired during resting state are characterized by spatial patterns of synchronous fluctuations, ultimately leading to the identification of robust brain networks. The resting-state brain networks, including the Default Mode Network (DMN), are demonstrated to persist during sustained task execution, but the exact features of task-related changes of network properties are still not well characterized. In this work we sought to examine in a group of 20 healthy volunteers (age 33 ± 6 years, 8 F/12 M) the relationship between changes of spectral and spatiotemporal features of one prominent resting-state network, namely the DMN, during the continuous execution of a working memory n-back task. We found that task execution impacted on both functional connectivity and amplitude of BOLD fluctuations within large parts of the DMN, but these changes correlated between each other only in a small area of the posterior cingulate. We conclude that combined analysis of multiple parameters related to connectivity, and their changes during the transition from resting state to continuous task execution, can contribute to a better understanding of how brain networks rearrange themselves in response to a task. PMID:28845420

Space station mobile transporter

NASA Technical Reports Server (NTRS)

Renshall, James; Marks, Geoff W.; Young, Grant L.

1988-01-01

The first quarter of the next century will see an operational space station that will provide a permanently manned base for satellite servicing, multiple strategic scientific and commercial payload deployment, and Orbital Maneuvering Vehicle/Orbital Transfer Vehicle (OMV/OTV) retrieval replenishment and deployment. The space station, as conceived, is constructed in orbit and will be maintained in orbit. The construction, servicing, maintenance and deployment tasks, when coupled with the size of the station, dictate that some form of transportation and manipulation device be conceived. The Transporter described will work in conjunction with the Orbiter and an Assembly Work Platform (AWP) to construct the Work Station. The Transporter will also work in conjunction with the Mobile Remote Servicer to service and install payloads, retrieve, service and deploy satellites, and service and maintain the station itself. The Transporter involved in station construction when mounted on the AWP and later supporting a maintenance or inspection task with the Mobile Remote Servicer and the Flight Telerobotic Servicer is shown.

Interset: A natural language interface for teleoperated robotic assembly of the EASE space structure

NASA Technical Reports Server (NTRS)

Boorsma, Daniel K.

1989-01-01

A teleoperated robot was used to assemble the Experimental Assembly of Structures in Extra-vehicular activity (EASE) space structure under neutral buoyancy conditions, simulating a telerobot performing structural assembly in the zero gravity of space. This previous work used a manually controlled teleoperator as a test bed for system performance evaluations. From these results several Artificial Intelligence options were proposed. One of these was further developed into a real time assembly planner. The interface for this system is effective in assembling EASE structures using windowed graphics and a set of networked menus. As the problem space becomes more complex and hence the set of control options increases, a natural language interface may prove to be beneficial to supplement the menu based control strategy. This strategy can be beneficial in situations such as: describing the local environment, maintaining a data base of task event histories, modifying a plan or a heuristic dynamically, summarizing a task in English, or operating in a novel situation.

Executive Functioning and Processing Speed in Age-Related Differences in Memory: Contribution of a Coding Task

ERIC Educational Resources Information Center

Baudouin, Alexia; Clarys, David; Vanneste, Sandrine; Isingrini, Michel

2009-01-01

The aim of the present study was to examine executive dysfunctioning and decreased processing speed as potential mediators of age-related differences in episodic memory. We compared the performances of young and elderly adults in a free-recall task. Participants were also given tests to measure executive functions and perceptual processing speed…

Aerobic Fitness and Cognitive Development: Event-Related Brain Potential and Task Performance Indices of Executive Control in Preadolescent Children

ERIC Educational Resources Information Center

Hillman, Charles H.; Buck, Sarah M.; Themanson, Jason R.; Pontifex, Matthew B.; Castelli, Darla M.

2009-01-01

The relationship between aerobic fitness and executive control was assessed in 38 higher- and lower-fit children (M[subscript age] = 9.4 years), grouped according to their performance on a field test of aerobic capacity. Participants performed a flanker task requiring variable amounts of executive control while event-related brain potential…

Multicenter validation of a bedside antisaccade task as a measure of executive function

PubMed Central

Hellmuth, J.; Mirsky, J.; Heuer, H.W.; Matlin, A.; Jafari, A.; Garbutt, S.; Widmeyer, M.; Berhel, A.; Sinha, L.; Miller, B.L.; Kramer, J.H.

2012-01-01

Objective: To create and validate a simple, standardized version of the antisaccade (AS) task that requires no specialized equipment for use as a measure of executive function in multicenter clinical studies. Methods: The bedside AS (BAS) task consisted of 40 pseudorandomized AS trials presented on a laptop computer. BAS performance was compared with AS performance measured using an infrared eye tracker in normal elders (NE) and individuals with mild cognitive impairment (MCI) or dementia (n = 33). The neuropsychological domain specificity of the BAS was then determined in a cohort of NE, MCI, and dementia (n = 103) at UCSF, and the BAS was validated as a measure of executive function in a 6-center cohort (n = 397) of normal adults and patients with a variety of brain diseases. Results: Performance on the BAS and laboratory AS task was strongly correlated and BAS performance was most strongly associated with neuropsychological measures of executive function. Even after controlling for disease severity and processing speed, BAS performance was associated with multiple assessments of executive function, most strongly the informant-based Frontal Systems Behavior Scale. Conclusions: The BAS is a simple, valid measure of executive function in aging and neurologic disease. PMID:22573640

The Link between Preschoolers' Executive Function and Theory of Mind and the Role of Epistemic States

ERIC Educational Resources Information Center

Henning, Anne; Spinath, Frank M.; Aschersleben, Gisa

2011-01-01

The aim of this study was to assess the specific relation between 3- to 6-year-olds' performance on a task measuring executive function (EF), the Dimensional Change Card Sort task (DCCS), and different developmental attainments in their theory of mind (ToM) by employing a battery of scaled ToM tasks that were comparable in task format and task…

Speed and Lateral Inhibition of Stimulus Processing Contribute to Individual Differences in Stroop-Task Performance.

PubMed

Naber, Marnix; Vedder, Anneke; Brown, Stephen B R E; Nieuwenhuis, Sander

2016-01-01

The Stroop task is a popular neuropsychological test that measures executive control. Strong Stroop interference is commonly interpreted in neuropsychology as a diagnostic marker of impairment in executive control, possibly reflecting executive dysfunction. However, popular models of the Stroop task indicate that several other aspects of color and word processing may also account for individual differences in the Stroop task, independent of executive control. Here we use new approaches to investigate the degree to which individual differences in Stroop interference correlate with the relative processing speed of word and color stimuli, and the lateral inhibition between visual stimuli. We conducted an electrophysiological and behavioral experiment to measure (1) how quickly an individual's brain processes words and colors presented in isolation (P3 latency), and (2) the strength of an individual's lateral inhibition between visual representations with a visual illusion. Both measures explained at least 40% of the variance in Stroop interference across individuals. As these measures were obtained in contexts not requiring any executive control, we conclude that the Stroop effect also measures an individual's pre-set way of processing visual features such as words and colors. This study highlights the important contributions of stimulus processing speed and lateral inhibition to individual differences in Stroop interference, and challenges the general view that the Stroop task primarily assesses executive control.

Development of Internet-Based Tasks for the Executive Function Performance Test.

PubMed

Rand, Debbie; Lee Ben-Haim, Keren; Malka, Rachel; Portnoy, Sigal

The Executive Function Performance Test (EFPT) is a reliable and valid performance-based tool to assess executive functions (EFs). This study's objective was to develop and verify two Internet-based tasks for the EFPT. A cross-sectional study assessed the alternate-form reliability of the Internet-based bill-paying and telephone-use tasks in healthy adults and people with subacute stroke (Study 1). It also sought to establish the tasks' criterion reliability for assessing EF deficits by correlating performance with that on the Trail Making Test in five groups: healthy young adults, healthy older adults, people with subacute stroke, people with chronic stroke, and young adults with attention deficit hyperactivity disorder (Study 2). The alternative-form reliability and initial construct validity for the Internet-based bill-paying task were verified. Criterion validity was established for both tasks. The Internet-based tasks are comparable to the original EFPT tasks and can be used for assessment of EF deficits. Copyright © 2018 by the American Occupational Therapy Association, Inc.

Executive Functions and Prefrontal Cortex: A Matter of Persistence?

PubMed Central

Ball, Gareth; Stokes, Paul R.; Rhodes, Rebecca A.; Bose, Subrata K.; Rezek, Iead; Wink, Alle-Meije; Lord, Louis-David; Mehta, Mitul A.; Grasby, Paul M.; Turkheimer, Federico E.

2011-01-01

Executive function is thought to originates from the dynamics of frontal cortical networks. We examined the dynamic properties of the blood oxygen level dependent time-series measured with functional MRI (fMRI) within the prefrontal cortex (PFC) to test the hypothesis that temporally persistent neural activity underlies performance in three tasks of executive function. A numerical estimate of signal persistence, the Hurst exponent, postulated to represent the coherent firing of cortical networks, was determined and correlated with task performance. Increasing persistence in the lateral PFC was shown to correlate with improved performance during an n-back task. Conversely, we observed a correlation between persistence and increasing commission error – indicating a failure to inhibit a prepotent response – during a Go/No-Go task. We propose that persistence within the PFC reflects dynamic network formation and these findings underline the importance of frequency analysis of fMRI time-series in the study of executive functions. PMID:21286223

Development of Advanced Robotic Hand System for space application

NASA Technical Reports Server (NTRS)

Machida, Kazuo; Akita, Kenzo; Mikami, Tatsuo; Komada, Satoru

1994-01-01

The Advanced Robotic Hand System (ARH) is a precise telerobotics system with a semi dexterous hand for future space application. The ARH will be tested in space as one of the missions of the Engineering Tests Satellite 7 (ETS-7) which will be launched in 1997. The objectives of the ARH development are to evaluate the capability of a possible robot hand for precise and delicate tasks and to validate the related technologies implemented in the system. The ARH is designed to be controlled both from ground as a teleoperation and by locally autonomous control. This paper presents the overall system design and the functional capabilities of the ARH as well as its mission outline as the preliminary design has been completed.

Regulative Loops, Step Loops and Task Loops

ERIC Educational Resources Information Center

VanLehn, Kurt

2016-01-01

This commentary suggests a generalization of the conception of the behavior of tutoring systems, which the target article characterized as having an outer loop that was executed once per task and an inner loop that was executed once per step of the task. A more general conception sees these two loops as instances of regulative loops, which…

Applying an Integrative Framework of Executive Function to Preschoolers With Specific Language Impairment.

PubMed

Kapa, Leah L; Plante, Elena; Doubleday, Kevin

2017-08-16

The first goal of this research was to compare verbal and nonverbal executive function abilities between preschoolers with and without specific language impairment (SLI). The second goal was to assess the group differences on 4 executive function components in order to determine if the components may be hierarchically related as suggested within a developmental integrative framework of executive function. This study included 26 4- and 5-year-olds diagnosed with SLI and 26 typically developing age- and sex-matched peers. Participants were tested on verbal and nonverbal measures of sustained selective attention, working memory, inhibition, and shifting. The SLI group performed worse compared with typically developing children on both verbal and nonverbal measures of sustained selective attention and working memory, the verbal inhibition task, and the nonverbal shifting task. Comparisons of standardized group differences between executive function measures revealed a linear increase with the following order: working memory, inhibition, shifting, and sustained selective attention. The pattern of results suggests that preschoolers with SLI have deficits in executive functioning compared with typical peers, and deficits are not limited to verbal tasks. A significant linear relationship between group differences across executive function components supports the possibility of a hierarchical relationship between executive function skills.

Executive and attentional contributions to Theory of Mind deficit in attention deficit/hyperactivity disorder (ADHD).

PubMed

Mary, Alison; Slama, Hichem; Mousty, Philippe; Massat, Isabelle; Capiau, Tatiana; Drabs, Virginie; Peigneux, Philippe

2016-01-01

Attention deficit/hyperactivity disorder (ADHD) in children has been associated with attentional and executive problems, but also with socioemotional difficulties possibly associated with deficits in Theory of Mind (ToM). Socioemotional problems in ADHD are associated with more negative prognoses, notably interpersonal, educational problems, and an increased risk of developing other psychiatric disorders that emphasize the need to clarify the nature of their ToM deficits. In this study, we hypothesized that ToM dysfunction in children with ADHD is largely attributable to their attentional and/or executive deficits. Thirty-one children with ADHD (8-12 years, IQ > 85) and 31 typically developing (TD) children were assessed using executive functions (inhibition, planning, and flexibility) and attentional tasks, as well as two advanced ToM tasks (Reading the Mind in the Eyes and Faux Pas) involving different levels of executive control. Children with ADHD performed more poorly than TD children in attentional, executive function, and ToM tasks. Linear regression analyses conducted in the ADHD group indicated that inhibition scores predicted performance on the "Faux Pas" task the best, while attention scores were the best for predicting performance on the Reading the Mind in the Eyes task. When controlled for inhibition and attentional variables, ToM performance in children with ADHD was actually similar to TD children. Contrarily, controlling for ToM scores did not normalize performance for inhibition and attentional tasks in children with ADHD. This unidirectional relationship suggests that deficits in the EF and attentional domains are responsible for ToM deficits in ADHD, which therefore may contribute to their socioemotional difficulties.

Neuropsychological function and suicidal behavior: attention control, memory and executive dysfunction in suicide attempt.

PubMed

Keilp, J G; Gorlyn, M; Russell, M; Oquendo, M A; Burke, A K; Harkavy-Friedman, J; Mann, J J

2013-03-01

Executive dysfunction, distinct from other cognitive deficits in depression, has been associated with suicidal behavior. However, this dysfunction is not found consistently across samples. Medication-free subjects with DSM-IV major depressive episode (major depressive disorder and bipolar type I disorder) and a past history of suicidal behavior (n = 72) were compared to medication-free depressed subjects with no history of suicidal behavior (n = 80) and healthy volunteers (n = 56) on a battery of tests assessing neuropsychological functions typically affected by depression (motor and psychomotor speed, attention, memory) and executive functions reportedly impaired in suicide attempters (abstract/contingent learning, working memory, language fluency, impulse control). All of the depressed subjects performed worse than healthy volunteers on motor, psychomotor and language fluency tasks. Past suicide attempters, in turn, performed worse than depressed non-attempters on attention and memory/working memory tasks [a computerized Stroop task, the Buschke Selective Reminding Task (SRT), the Benton Visual Retention Test (VRT) and an N-back task] but not on other executive function measures, including a task associated with ventral prefrontal function (Object Alternation). Deficits were not accounted for by current suicidal ideation or the lethality of past attempts. A small subsample of those using a violent method in their most lethal attempt showed a pattern of poor executive performance. Deficits in specific components of attention control, memory and working memory were associated with suicidal behavior in a sample where non-violent attempt predominated. Broader executive dysfunction in depression may be associated with specific forms of suicidal behavior, rather than suicidal behavior per se.

Emotional verbal fluency: a new task on emotion and executive function interaction.

PubMed

Sass, Katharina; Fetz, Karolina; Oetken, Sarah; Habel, Ute; Heim, Stefan

2013-09-01

The present study introduces "Emotional Verbal Fluency" as a novel (partially computerized) task, which is aimed to investigate the interaction between emotionally loaded words and executive functions. Verbal fluency tasks are thought to measure executive functions but the interaction with emotional aspects is hardly investigated. In the current study, a group of healthy subjects (n = 21, mean age 25 years, 76% females) were asked to generate items that are either part of a semantic category (e.g., plants, toys, vehicles; standard semantic verbal fluency) or can trigger the emotions joy, anger, sadness, fear and disgust. The results of the task revealed no differences between performance on semantic and emotional categories, suggesting a comparable task difficulty for healthy subjects. Hence, these first results on the comparison between semantic and emotional verbal fluency seem to highlight that both might be suitable for examining executive functioning. However, an interaction was found between the category type and repetition (first vs. second sequence of the same category) with larger performance decrease for semantic in comparison to emotional categories. Best performance overall was found for the emotional category "joy" suggesting a positivity bias in healthy subjects. To conclude, emotional verbal fluency is a promising approach to investigate emotional components in an executive task, which may stimulate further research, especially in psychiatric patients who suffer from emotional as well as cognitive deficits.

Emotional Verbal Fluency: A New Task on Emotion and Executive Function Interaction

PubMed Central

Sass, Katharina; Fetz, Karolina; Oetken, Sarah; Habel, Ute; Heim, Stefan

2013-01-01

The present study introduces “Emotional Verbal Fluency” as a novel (partially computerized) task, which is aimed to investigate the interaction between emotionally loaded words and executive functions. Verbal fluency tasks are thought to measure executive functions but the interaction with emotional aspects is hardly investigated. In the current study, a group of healthy subjects (n = 21, mean age 25 years, 76% females) were asked to generate items that are either part of a semantic category (e.g., plants, toys, vehicles; standard semantic verbal fluency) or can trigger the emotions joy, anger, sadness, fear and disgust. The results of the task revealed no differences between performance on semantic and emotional categories, suggesting a comparable task difficulty for healthy subjects. Hence, these first results on the comparison between semantic and emotional verbal fluency seem to highlight that both might be suitable for examining executive functioning. However, an interaction was found between the category type and repetition (first vs. second sequence of the same category) with larger performance decrease for semantic in comparison to emotional categories. Best performance overall was found for the emotional category “joy” suggesting a positivity bias in healthy subjects. To conclude, emotional verbal fluency is a promising approach to investigate emotional components in an executive task, which may stimulate further research, especially in psychiatric patients who suffer from emotional as well as cognitive deficits. PMID:25379243

Executive functioning in schizophrenia: Unique and shared variance with measures of fluid intelligence.

PubMed

Martin, A K; Mowry, B; Reutens, D; Robinson, G A

2015-10-01

Patients with schizophrenia often display deficits on tasks thought to measure "executive" processes. Recently, it has been suggested that reductions in fluid intelligence test performance entirely explain deficits reported for patients with focal frontal lesions on classical executive tasks. For patients with schizophrenia, it is unclear whether deficits on executive tasks are entirely accountable by fluid intelligence and representative of a common general process or best accounted for by distinct contributions to the cognitive profile of schizophrenia. In the current study, 50 patients with schizophrenia and 50 age, sex and premorbid intelligence matched controls were assessed using a broad neuropsychological battery, including tasks considered sensitive to executive abilities, namely the Hayling Sentence Completion Test (HSCT), word fluency, Stroop test, digit-span backwards, and spatial working memory. Fluid intelligence was measured using both the Matrix reasoning subtest from the Weschler Abbreviated Scale of Intelligence (WASI) and a composite score derived from a number of cognitive tests. Patients with schizophrenia were impaired on all cognitive measures compared with controls, except smell identification and the optimal betting and risk-taking measures from the Cambridge Gambling Task. After introducing fluid intelligence as a covariate, significant differences remained for HSCT suppression errors, and classical executive function tests such as the Stroop test and semantic/phonemic word fluency, regardless of which fluid intelligence measure was included. Fluid intelligence does not entirely explain impaired performance on all tests considered as reflecting "executive" processes. For schizophrenia, these measures should remain part of a comprehensive neuropsychological assessment alongside a measure of fluid intelligence. Copyright © 2015 Elsevier Inc. All rights reserved.

The restless mind.

PubMed

Smallwood, Jonathan; Schooler, Jonathan W

2006-11-01

This article reviews the hypothesis that mind wandering can be integrated into executive models of attention. Evidence suggests that mind wandering shares many similarities with traditional notions of executive control. When mind wandering occurs, the executive components of attention appear to shift away from the primary task, leading to failures in task performance and superficial representations of the external environment. One challenge for incorporating mind wandering into standard executive models is that it often occurs in the absence of explicit intention--a hallmark of controlled processing. However, mind wandering, like other goal-related processes, can be engaged without explicit awareness; thus, mind wandering can be seen as a goal-driven process, albeit one that is not directed toward the primary task. (c) 2006 APA, All Rights Reserved.

Remote systems development

NASA Technical Reports Server (NTRS)

Olsen, R.; Schaefer, O.; Hussey, J.

1992-01-01

Potential space missions of the nineties and the next century require that we look at the broad category of remote systems as an important means to achieve cost-effective operations, exploration and colonization objectives. This paper addresses such missions, which can use remote systems technology as the basis for identifying required capabilities which must be provided. The relationship of the space-based tasks to similar tasks required for terrestrial applications is discussed. The development status of the required technology is assessed and major issues which must be addressed to meet future requirements are identified. This includes the proper mix of humans and machines, from pure teleoperation to full autonomy; the degree of worksite compatibility for a robotic system; and the required design parameters, such as degrees-of-freedom. Methods for resolution are discussed including analysis, graphical simulation and the use of laboratory test beds. Grumman experience in the application of these techniques to a variety of design issues are presented utilizing the Telerobotics Development Laboratory which includes a 17-DOF robot system, a variety of sensing elements, Deneb/IRIS graphics workstations and control stations. The use of task/worksite mockups, remote system development test beds and graphical analysis are discussed with examples of typical results such as estimates of task times, task feasibility and resulting recommendations for design changes. The relationship of this experience and lessons-learned to future development of remote systems is also discussed.

Implementing forward recovery using checkpointing in distributed systems

NASA Technical Reports Server (NTRS)

Long, Junsheng; Fuchs, W. K.; Abraham, Jacob A.

1991-01-01

The paper describes the implementation of a forward recovery scheme using checkpoints and replicated tasks. The implementation is based on the concept of lookahead execution and rollback validation. In the experiment, two tasks are selected for the normal execution and one for rollback validation. It is shown that the recovery strategy has nearly error-free execution time and an average redundancy lower than TMR.

[Impairment of executive function in elderly patients with major unipolar depression: influence of psychomotor retardation].

PubMed

Baudic, Sophie; Benisty, Sarah; Dalla Barba, Gianfrano; Traykov, Latchezar

2007-03-01

The results from several studies assessing the executive function in depressed patients compared to control subjects varied from significant impairment to normal performance. To assess the executive impairment in elderly patients with major unipolar depression and to evaluate the influence of psychomotor retardation and severity of depression in the executive deficits, the performance of 15 elderly patients with unipolar depression was compared to that of 15 elderly control subjects on executive tasks. The severity of depression was evaluated by the Montgomery and Asberg depressive scale and that of psychomotor retardation by the Widlöcher's scale. In depressed patients, deficits were found on tasks assessing cognitive flexibility (Modified card sorting test (MCST) and Trail making test B), planification and elaboration of strategies (cognitive estimates), motor initiation (graphic sequences), categorisation and hypothesis making (MCST) and interference resistance (Stroop test). However, depressed patients performed normally on the Hayling test assessing the inhibition processes. Intensity of psychomotor retardation was not correlated to the performance of executive tasks. Conversely, severity of depression was related to the scores of MCST (number of errors and perseverations), Stroop and Hayling tests (time taken to complete the end of the sentence). Unipolar depressed patients showed deficits in most tasks assessing executive function. However, inhibition processes appeared to be intact in depressed patients although their implementation was difficult. The severity of depression but not that of psychomotor retardation was associated with executive deficits.

Pragmatic and executive functions in traumatic brain injury and right brain damage: An exploratory comparative study

PubMed Central

Zimmermann, Nicolle; Gindri, Gigiane; de Oliveira, Camila Rosa; Fonseca, Rochele Paz

2011-01-01

Objective To describe the frequency of pragmatic and executive deficits in right brain damaged (RBD) and in traumatic brain injury (TBI) patients, and to verify possible dissociations between pragmatic and executive functions in these two groups. Methods The sample comprised 7 cases of TBI and 7 cases of RBD. All participants were assessed by means of tasks from the Montreal Communication Evaluation Battery and executive functions tests including the Trail Making Test, Hayling Test, Wisconsin Card Sorting Test, semantic and phonemic verbal fluency tasks, and working memory tasks from the Brazilian Brief Neuropsychological Assessment Battery NEUPSILIN. Z-score was calculated and a descriptive analysis of frequency of deficits (Z< -1.5) was carried out. Results RBD patients presented with deficits predominantly on conversational and narrative discursive tasks, while TBI patients showed a wider spread pattern of pragmatic deficits. Regarding EF, RBD deficits included predominantly working memory and verbal initiation impairment. On the other hand, TBI individuals again exhibited a general profile of executive dysfunction, affecting mainly working memory, initiation, inhibition, planning and switching. Pragmatic and executive deficits were generally associated upon comparisons of RBD patients and TBI cases, except for two simple dissociations: two post-TBI cases showed executive deficits in the absence of pragmatic deficits. Discussion Pragmatic and executive deficits can be very frequent following TBI or vascular RBD. There seems to be an association between these abilities, indicating that although they can co-occur, a cause-consequence relationship cannot be the only hypothesis. PMID:29213762

Development and preliminary reliability of a multitasking assessment for executive functioning after concussion.

PubMed

Smith, Laurel B; Radomski, Mary Vining; Davidson, Leslie Freeman; Finkelstein, Marsha; Weightman, Margaret M; McCulloch, Karen L; Scherer, Matthew R

2014-01-01

OBJECTIVES. Executive functioning deficits may result from concussion. The Charge of Quarters (CQ) Duty Task is a multitask assessment designed to assess executive functioning in servicemembers after concussion. In this article, we discuss the rationale and process used in the development of the CQ Duty Task and present pilot data from the preliminary evaluation of interrater reliability (IRR). METHOD. Three evaluators observed as 12 healthy participants performed the CQ Duty Task and measured performance using various metrics. Intraclass correlation coefficient (ICC) quantified IRR. RESULTS. The ICC for task completion was .94. ICCs for other assessment metrics were variable. CONCLUSION. Preliminary IRR data for the CQ Duty Task are encouraging, but further investigation is needed to improve IRR in some domains. Lessons learned in the development of the CQ Duty Task could benefit future test development efforts with populations other than the military. Copyright © 2014 by the American Occupational Therapy Association, Inc.

Development and Preliminary Reliability of a Multitasking Assessment for Executive Functioning After Concussion

PubMed Central

Radomski, Mary Vining; Davidson, Leslie Freeman; Finkelstein, Marsha; Weightman, Margaret M.; McCulloch, Karen L.; Scherer, Matthew R.

2014-01-01

OBJECTIVES. Executive functioning deficits may result from concussion. The Charge of Quarters (CQ) Duty Task is a multitask assessment designed to assess executive functioning in servicemembers after concussion. In this article, we discuss the rationale and process used in the development of the CQ Duty Task and present pilot data from the preliminary evaluation of interrater reliability (IRR). METHOD. Three evaluators observed as 12 healthy participants performed the CQ Duty Task and measured performance using various metrics. Intraclass correlation coefficient (ICC) quantified IRR. RESULTS. The ICC for task completion was .94. ICCs for other assessment metrics were variable. CONCLUSION. Preliminary IRR data for the CQ Duty Task are encouraging, but further investigation is needed to improve IRR in some domains. Lessons learned in the development of the CQ Duty Task could benefit future test development efforts with populations other than the military. PMID:25005507

Children's planning performance in the Zoo Map task (BADS-C): Is it driven by general cognitive ability, executive functioning, or prospection?

PubMed

Ballhausen, Nicola; Mahy, Caitlin E V; Hering, Alexandra; Voigt, Babett; Schnitzspahn, Katharina M; Lagner, Prune; Ihle, Andreas; Kliegel, Matthias

2017-01-01

A minimal amount of research has examined the cognitive predictors of children's performance in naturalistic, errand-type planning tasks such as the Zoo Map task of the Behavioral Assessment of the Dysexecutive Syndrome for Children (BADS-C). Thus, the current study examined prospection (i.e., the ability to remember to carry out a future intention), executive functioning, and intelligence markers as predictors of performance in this widely used naturalistic planning task in 56 children aged 7- to 12-years-old. Measures of planning, prospection, inhibition, crystallized intelligence, and fluid intelligence were collected in an individual differences study. Regression analyses showed that prospection (rather than traditional measures of intelligence or inhibition) predicted planning, suggesting that naturalistic planning tasks such as the Zoo Map task may rely on future-oriented cognitive processes rather than executive problem solving or general knowledge.

Can training in a real-time strategy video game attenuate cognitive decline in older adults?

PubMed

Basak, Chandramallika; Boot, Walter R; Voss, Michelle W; Kramer, Arthur F

2008-12-01

Declines in various cognitive abilities, particularly executive control functions, are observed in older adults. An important goal of cognitive training is to slow or reverse these age-related declines. However, opinion is divided in the literature regarding whether cognitive training can engender transfer to a variety of cognitive skills in older adults. In the current study, the authors trained older adults in a real-time strategy video game for 23.5 hr in an effort to improve their executive functions. A battery of cognitive tasks, including tasks of executive control and visuospatial skills, were assessed before, during, and after video-game training. The trainees improved significantly in the measures of game performance. They also improved significantly more than the control participants in executive control functions, such as task switching, working memory, visual short-term memory, and reasoning. Individual differences in changes in game performance were correlated with improvements in task switching. The study has implications for the enhancement of executive control processes of older adults. Copyright (c) 2009 APA, all rights reserved.

Localized Fault Recovery for Nested Fork-Join Programs

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

Kestor, Gokcen; Krishnamoorthy, Sriram; Ma, Wenjing

Nested fork-join programs scheduled using work stealing can automatically balance load and adapt to changes in the execution environment. In this paper, we design an approach to efficiently recover from faults encountered by these programs. Specifically, we focus on localized recovery of the task space in the presence of fail-stop failures. We present an approach to efficiently track, under work stealing, the relationships between the work executed by various threads. This information is used to identify and schedule the tasks to be re-executed without interfering with normal task execution. The algorithm precisely computes the work lost, incurs minimal re-execution overhead,more » and can recover from an arbitrary number of failures. Experimental evaluation demonstrates low overheads in the absence of failures, recovery overheads on the same order as the lost work, and much lower recovery costs than alternative strategies.« less

Anterior medial prefrontal cortex exhibits activation during task preparation but deactivation during task execution.

PubMed

Koshino, Hideya; Minamoto, Takehiro; Ikeda, Takashi; Osaka, Mariko; Otsuka, Yuki; Osaka, Naoyuki

2011-01-01

The anterior prefrontal cortex (PFC) exhibits activation during some cognitive tasks, including episodic memory, reasoning, attention, multitasking, task sets, decision making, mentalizing, and processing of self-referenced information. However, the medial part of anterior PFC is part of the default mode network (DMN), which shows deactivation during various goal-directed cognitive tasks compared to a resting baseline. One possible factor for this pattern is that activity in the anterior medial PFC (MPFC) is affected by dynamic allocation of attentional resources depending on task demands. We investigated this possibility using an event related fMRI with a face working memory task. Sixteen students participated in a single fMRI session. They were asked to form a task set to remember the faces (Face memory condition) or to ignore them (No face memory condition), then they were given 6 seconds of preparation period before the onset of the face stimuli. During this 6-second period, four single digits were presented one at a time at the center of the display, and participants were asked to add them and to remember the final answer. When participants formed a task set to remember faces, the anterior MPFC exhibited activation during a task preparation period but deactivation during a task execution period within a single trial. The results suggest that the anterior MPFC plays a role in task set formation but is not involved in execution of the face working memory task. Therefore, when attentional resources are allocated to other brain regions during task execution, the anterior MPFC shows deactivation. The results suggest that activation and deactivation in the anterior MPFC are affected by dynamic allocation of processing resources across different phases of processing.

Anterior Medial Prefrontal Cortex Exhibits Activation during Task Preparation but Deactivation during Task Execution

PubMed Central

Koshino, Hideya; Minamoto, Takehiro; Ikeda, Takashi; Osaka, Mariko; Otsuka, Yuki; Osaka, Naoyuki

2011-01-01

Background The anterior prefrontal cortex (PFC) exhibits activation during some cognitive tasks, including episodic memory, reasoning, attention, multitasking, task sets, decision making, mentalizing, and processing of self-referenced information. However, the medial part of anterior PFC is part of the default mode network (DMN), which shows deactivation during various goal-directed cognitive tasks compared to a resting baseline. One possible factor for this pattern is that activity in the anterior medial PFC (MPFC) is affected by dynamic allocation of attentional resources depending on task demands. We investigated this possibility using an event related fMRI with a face working memory task. Methodology/Principal Findings Sixteen students participated in a single fMRI session. They were asked to form a task set to remember the faces (Face memory condition) or to ignore them (No face memory condition), then they were given 6 seconds of preparation period before the onset of the face stimuli. During this 6-second period, four single digits were presented one at a time at the center of the display, and participants were asked to add them and to remember the final answer. When participants formed a task set to remember faces, the anterior MPFC exhibited activation during a task preparation period but deactivation during a task execution period within a single trial. Conclusions/Significance The results suggest that the anterior MPFC plays a role in task set formation but is not involved in execution of the face working memory task. Therefore, when attentional resources are allocated to other brain regions during task execution, the anterior MPFC shows deactivation. The results suggest that activation and deactivation in the anterior MPFC are affected by dynamic allocation of processing resources across different phases of processing. PMID:21829668

Do attentional capacities and processing speed mediate the effect of age on executive functioning?

PubMed

Gilsoul, Jessica; Simon, Jessica; Hogge, Michaël; Collette, Fabienne

2018-02-06

The executive processes are well known to decline with age, and similar data also exists for attentional capacities and processing speed. Therefore, we investigated whether these two last nonexecutive variables would mediate the effect of age on executive functions (inhibition, shifting, updating, and dual-task coordination). We administered a large battery of executive, attentional and processing speed tasks to 104 young and 71 older people, and we performed mediation analyses with variables showing a significant age effect. All executive and processing speed measures showed age-related effects while only the visual scanning task performance (selective attention) was explained by age when controlled for gender and educational level. Regarding mediation analyses, visual scanning partially mediated the age effect on updating while processing speed partially mediated the age effect on shifting, updating and dual-task coordination. In a more exploratory way, inhibition was also found to partially mediate the effect of age on the three other executive functions. Attention did not greatly influence executive functioning in aging while, in agreement with the literature, processing speed seems to be a major mediator of the age effect on these processes. Interestingly, the global pattern of results seems also to indicate an influence of inhibition but further studies are needed to confirm the role of that variable as a mediator and its relative importance by comparison with processing speed.

Exploiting Vector and Multicore Parallelsim for Recursive, Data- and Task-Parallel Programs

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

Ren, Bin; Krishnamoorthy, Sriram; Agrawal, Kunal

Modern hardware contains parallel execution resources that are well-suited for data-parallelism-vector units-and task parallelism-multicores. However, most work on parallel scheduling focuses on one type of hardware or the other. In this work, we present a scheduling framework that allows for a unified treatment of task- and data-parallelism. Our key insight is an abstraction, task blocks, that uniformly handles data-parallel iterations and task-parallel tasks, allowing them to be scheduled on vector units or executed independently as multicores. Our framework allows us to define schedulers that can dynamically select between executing task- blocks on vector units or multicores. We show that thesemore » schedulers are asymptotically optimal, and deliver the maximum amount of parallelism available in computation trees. To evaluate our schedulers, we develop program transformations that can convert mixed data- and task-parallel pro- grams into task block-based programs. Using a prototype instantiation of our scheduling framework, we show that, on an 8-core system, we can simultaneously exploit vector and multicore parallelism to achieve 14×-108× speedup over sequential baselines.« less

Development of Hot and Cool Executive Function during the Transition to Adolescence

ERIC Educational Resources Information Center

Prencipe, Angela; Kesek, Amanda; Cohen, Julia; Lamm, Connie; Lewis, Marc D.; Zelazo, Philip David

2011-01-01

This study examined the development of executive function (EF) in a typically developing sample from middle childhood to adolescence using a range of tasks varying in affective significance. A total of 102 participants between 8 and 15 years of age completed the Iowa Gambling Task, the Color Word Stroop, a Delay Discounting task, and a Digit Span…

Individual Differences in Executive Functioning Predict Preschoolers' Improvement from Theory-of-Mind Training

ERIC Educational Resources Information Center

Benson, Jeannette E.; Sabbagh, Mark A.; Carlson, Stephanie M.; Zelazo, Philip David

2013-01-01

Twenty-four 3.5-year-old children who initially showed poor performance on false-belief tasks participated in a training protocol designed to promote performance on these tasks. Our aim was to determine whether the extent to which children benefited from training was predicted by their performance on a battery of executive functioning tasks.…

Human-Robot Interaction: Status and Challenges.

PubMed

Sheridan, Thomas B

2016-06-01

The current status of human-robot interaction (HRI) is reviewed, and key current research challenges for the human factors community are described. Robots have evolved from continuous human-controlled master-slave servomechanisms for handling nuclear waste to a broad range of robots incorporating artificial intelligence for many applications and under human supervisory control. This mini-review describes HRI developments in four application areas and what are the challenges for human factors research. In addition to a plethora of research papers, evidence of success is manifest in live demonstrations of robot capability under various forms of human control. HRI is a rapidly evolving field. Specialized robots under human teleoperation have proven successful in hazardous environments and medical application, as have specialized telerobots under human supervisory control for space and repetitive industrial tasks. Research in areas of self-driving cars, intimate collaboration with humans in manipulation tasks, human control of humanoid robots for hazardous environments, and social interaction with robots is at initial stages. The efficacy of humanoid general-purpose robots has yet to be proven. HRI is now applied in almost all robot tasks, including manufacturing, space, aviation, undersea, surgery, rehabilitation, agriculture, education, package fetch and delivery, policing, and military operations. © 2016, Human Factors and Ergonomics Society.

Task-related modulations of BOLD low-frequency fluctuations within the default mode network

NASA Astrophysics Data System (ADS)

Tommasin, Silvia; Mascali, Daniele; Gili, Tommaso; Eid Assan, Ibrahim; Moraschi, Marta; Fratini, Michela; Wise, Richard G.; Macaluso, Emiliano; Mangia, Silvia; Giove, Federico

2017-07-01

Spontaneous low-frequency Blood-Oxygenation Level-Dependent (BOLD) signals acquired during resting state are characterized by spatial patterns of synchronous fluctuations, ultimately leading to the identification of robust brain networks. The resting-state brain networks, including the Default Mode Network (DMN), are demonstrated to persist during sustained task execution, but the exact features of task-related changes of network properties are still not well characterized. In this work we sought to examine in a group of 20 healthy volunteers (age 33±6 years, 8F/12M) the relationship between changes of spectral and spatiotemporal features of one prominent resting-state network, namely the DMN, during the steady-state execution of a sustained working memory n-back task. We found that the steady state execution of such a task impacted on both functional connectivity and amplitude of BOLD fluctuations within large parts of the DMN, but these changes correlated between each other only in a small area of the posterior cingulate. We conclude that combined analysis of multiple parameters related to connectivity, and their changes during the transition from resting state to steady-state task execution, can contribute to a better understanding of how brain networks rearrange themselves in response of a task.

Long-term memory-based control of attention in multi-step tasks requires working memory: evidence from domain-specific interference

PubMed Central

Foerster, Rebecca M.; Carbone, Elena; Schneider, Werner X.

2014-01-01

Evidence for long-term memory (LTM)-based control of attention has been found during the execution of highly practiced multi-step tasks. However, does LTM directly control for attention or are working memory (WM) processes involved? In the present study, this question was investigated with a dual-task paradigm. Participants executed either a highly practiced visuospatial sensorimotor task (speed stacking) or a verbal task (high-speed poem reciting), while maintaining visuospatial or verbal information in WM. Results revealed unidirectional and domain-specific interference. Neither speed stacking nor high-speed poem reciting was influenced by WM retention. Stacking disrupted the retention of visuospatial locations, but did not modify memory performance of verbal material (letters). Reciting reduced the retention of verbal material substantially whereas it affected the memory performance of visuospatial locations to a smaller degree. We suggest that the selection of task-relevant information from LTM for the execution of overlearned multi-step tasks recruits domain-specific WM. PMID:24847304

Reconfiguration of brain network architecture to support executive control in aging.

PubMed

Gallen, Courtney L; Turner, Gary R; Adnan, Areeba; D'Esposito, Mark

2016-08-01

Aging is accompanied by declines in executive control abilities and changes in underlying brain network architecture. Here, we examined brain networks in young and older adults during a task-free resting state and an N-back task and investigated age-related changes in the modular network organization of the brain. Compared with young adults, older adults showed larger changes in network organization between resting state and task. Although young adults exhibited increased connectivity between lateral frontal regions and other network modules during the most difficult task condition, older adults also exhibited this pattern of increased connectivity during less-demanding task conditions. Moreover, the increase in between-module connectivity in older adults was related to faster task performance and greater fractional anisotropy of the superior longitudinal fasciculus. These results demonstrate that older adults who exhibit more pronounced network changes between a resting state and task have better executive control performance and greater structural connectivity of a core frontal-posterior white matter pathway. Copyright © 2016 Elsevier Inc. All rights reserved.

Automated Telerobotic Inspection Of Surfaces

NASA Technical Reports Server (NTRS)

Balaram, J.; Prasad, K. Venkatesh

1996-01-01

Method of automated telerobotic inspection of surfaces undergoing development. Apparatus implementing method includes video camera that scans over surfaces to be inspected, in manner of mine detector. Images of surfaces compared with reference images to detect flaws. Developed for inspecting external structures of Space Station Freedom for damage from micrometeorites and debris from prior artificial satellites. On Earth, applied to inspection for damage, missing parts, contamination, and/or corrosion on interior surfaces of pipes or exterior surfaces of bridges, towers, aircraft, and ships.

Telerobotics test bed for space structure assembly

NASA Technical Reports Server (NTRS)

Kitami, M.; Ogimoto, K.; Yasumoto, F.; Katsuragawa, T.; Itoko, T.; Kurosaki, Y.; Hirai, S.; Machida, K.

1994-01-01

A cooperative research on super long distance space telerobotics is now in progress both in Japan and USA. In this program. several key features will be tested, which can be applicable to the control of space robots as well as to terrestrial robots. Local (control) and remote (work) sites will be shared between Electrotechnical Lab (ETL) of MITI in Japan and Jet Propulsion Lab (JPL) in USA. The details of a test bed for this international program are discussed in this report.

The Role of Executive Control and Readiness to Change in Problematic Drinkers with Mild to Borderline Intellectual Disability.

PubMed

van Duijvenbode, Neomi; Didden, Robert; Korzilius, Hubert P L M; Engels, Rutger C M E

2017-09-01

Problematic alcohol use is associated with neuropsychological consequences, including cognitive biases. The goal of the study was to explore the moderating role of executive control and readiness to change on the relationship between alcohol use and cognitive biases in light and problematic drinkers with and without mild to borderline intellectual disability (MBID). Participants (N = 112) performed the visual dot probe task to measure the strength of the cognitive biases. Executive control was measured using two computerised tasks for working memory capacity (Corsi block-tapping task) and inhibitory control (Go/No-go task). Readiness to change was measured using the Readiness to Change Questionnaire. No cognitive biases or executive dysfunctions were found in problematic drinkers. Working memory capacity and inhibitory control were impaired among individuals with MBID, irrespective of severity of alcohol use-related problems. Executive control and readiness to change did not moderate the relationship between alcohol use and cognitive biases. The results fail to support the dual-process models of addiction, but results need to be treated with caution given the problematic psychometric qualities of the visual dot probe task. Implementing a neurocognitive assessment and protocols in the treatment of substance use disorders seems premature. © 2016 John Wiley & Sons Ltd.

Cooperative mission execution and planning

NASA Astrophysics Data System (ADS)

Flann, Nicholas S.; Saunders, Kevin S.; Pells, Larry

1998-08-01

Utilizing multiple cooperating autonomous vehicles to perform tasks enhances robustness and efficiency over the use of a single vehicle. Furthermore, because autonomous vehicles can be controlled precisely and their status known accurately in real time, new types of cooperative behaviors are possible. This paper presents a working system called MEPS that plans and executes missions for multiple autonomous vehicles in large structured environments. Two generic spatial tasks are supported, to sweep an area and to visit a location while activating on-board equipment. Tasks can be entered both initially by the user and dynamically during mission execution by both users and vehicles. Sensor data and task achievement data is shared among the vehicles enabling them to cooperatively adapt to changing environmental, vehicle and tasks conditions. The system has been successfully applied to control ATV and micro-robotic vehicles in precision agriculture and waste-site characterization environments.

Prefrontal cortex dysfunction and 'Jumping to Conclusions': bias or deficit?

PubMed

Lunt, Laura; Bramham, Jessica; Morris, Robin G; Bullock, Peter R; Selway, Richard P; Xenitidis, Kiriakos; David, Anthony S

2012-03-01

The 'beads task' is used to measure the cognitive basis of delusions, namely the 'Jumping to Conclusions' (JTC) reasoning bias. However, it is not clear whether the task merely taps executive dysfunction - known to be impaired in patients with schizophrenia - such as planning and resistance to impulse. To study this, 19 individuals with neurosurgical excisions to the prefrontal cortex, 21 unmedicated adults with Attention Deficit Hyperactivity Disorder (ADHD), and 25 healthy controls completed two conditions of the beads task, in addition to tests of memory and executive function as well as control tests of probabilistic reasoning ability. The results indicated that the prefrontal lobe group (in particular, those with left-sided lesions) demonstrated a JTC bias relative to the ADHD and control groups. Further exploratory analyses indicated that JTC on the beads task was associated with poorer performance in certain executive domains. The results are discussed in terms of the executive demands of the beads task and possible implications for the model of psychotic delusions based on the JTC bias. ©2011 The British Psychological Society.

Transcranial Direct Current Stimulation Improves Executive Dysfunctions in ADHD: Implications for Inhibitory Control, Interference Control, Working Memory, and Cognitive Flexibility.

PubMed

Nejati, Vahid; Salehinejad, Mohammad Ali; Nitsche, Michael A; Najian, Asal; Javadi, Amir-Homayoun

2017-09-01

This study examined effects of transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (DLPFC) and orbitofrontal cortex (OFC) on major executive functions (EFs), including response inhibition, executive control, working memory (WM), and cognitive flexibility/task switching in ADHD. ADHD children received (a) left anodal/right cathodal DLPFC tDCS and (b) sham stimulation in Experiment 1 and (a) left anodal DLPFC/right cathodal OFC tDCS, (b) left cathodal DLPFC/right anodal OFC tDCS, and (c) sham stimulation in Experiment 2. The current intensity was 1 mA for 15 min with a 72-hr interval between sessions. Participants underwent Go/No-Go task, N-back test, Wisconsin Card Sorting Test (WCST), and Stroop task after each tDCS condition. Anodal left DLPFC tDCS most clearly affected executive control functions (e.g., WM, interference inhibition), while cathodal left DLPFC tDCS improved inhibitory control. Cognitive flexibility/task switching benefited from combined DLPFC-OFC, but not DLPFC stimulation alone. Task-specific stimulation protocols can improve EFs in ADHD.

Operate A Chemical Surety Program And Studies Supporting The Medical Chemical Defense Research Program

DTIC Science & Technology

2010-05-01

23 Task Execution Plan 34 – Temperature Testing of Pyridostigmine Bromide (PB) .......... 23 KEY RESEARCH ACCOMPLISHMENTS...29, 2010. Staff was assembled and materials have been ordered. Task Execution Plan (TEP) 0034 – Temperature Testing of Pyridostigmine Bromide

The development of inhibitory control in preschool children: effects of "executive skills" training.

PubMed

Dowsett, S M; Livesey, D J

2000-03-01

As one of several processes involved in the executive functioning of the cognitive system, inhibitory control plays a significant role in determining how various mental processes work together in the successful performance of a task. Studies of response inhibition have shown that although 3-year-old children have the cognitive capacity to learn the rules required for response control, indicated by the correct verbal response, developmental constraints prevent them from withholding the correct response (Bell & Livesey, 1985; Livesey & Morgan, 1991). Some argue that these abulic dissociations are relative to children's ability to reflect on the rules required for response control (Zelazo, Reznick, & Pinon, 1995). The current study showed that repeated exposure to tasks facilitating the acquisition of increasingly complex rule structures could improve inhibitory control (as measured by a go/no-go discrimination learning task), even in children aged 3 years. These tasks included a variant of Diamond and Boyer's (1989) modified version of the Wisconsin Card Sort Task and a simplification of the change paradigm (Logan & Burkell, 1986). It is argued that experience with these tasks increased the acquisition of complex rules by placing demands on executive processes. This includes response control and other executive functions, such as representational flexibility, the ability to maintain information in working memory, the selective control of attention, and proficiency at error correction. The role of experiential variables in the development of inhibitory control is discussed in terms of the interaction between neural development and appropriate executive task experience in the early years. Copyright 2000 John Wiley & Sons, Inc.

Development and demonstration of a telerobotic excavation system

NASA Technical Reports Server (NTRS)

Burks, Barry L.; Thompson, David H.; Killough, Stephen M.; Dinkins, Marion A.

1994-01-01

Oak Ridge National Laboratory is developing remote excavation technologies for the Department of Energy's Office (DOE) of Technology Development, Robotics Technology Development Program, and also for the Department of Defense (DOD) Project Manager for Ammunition Logistics. This work is being done to meet the need for remote excavation and removal of radioactive and contaminated buried waste at several DOE sites and unexploded ordnance at DOD sites. System requirements are based on the need to uncover and remove waste from burial sites in a way that does not cause unnecessary personnel exposure or additional environmental contamination. Goals for the current project are to demonstrate dexterous control of a backhoe with force feedback and to implement robotic operations that will improve productivity. The Telerobotic Small Emplacement Excavator is a prototype system that incorporates the needed robotic and telerobotic capabilities on a commercially available platform. The ability to add remote dexterous teleoperation and robotic operating modes is intended to be adaptable to other commercially available excavator systems.

Neural-Learning-Based Telerobot Control With Guaranteed Performance.

PubMed

Yang, Chenguang; Wang, Xinyu; Cheng, Long; Ma, Hongbin

2017-10-01

In this paper, a neural networks (NNs) enhanced telerobot control system is designed and tested on a Baxter robot. Guaranteed performance of the telerobot control system is achieved at both kinematic and dynamic levels. At kinematic level, automatic collision avoidance is achieved by the control design at the kinematic level exploiting the joint space redundancy, thus the human operator would be able to only concentrate on motion of robot's end-effector without concern on possible collision. A posture restoration scheme is also integrated based on a simulated parallel system to enable the manipulator restore back to the natural posture in the absence of obstacles. At dynamic level, adaptive control using radial basis function NNs is developed to compensate for the effect caused by the internal and external uncertainties, e.g., unknown payload. Both the steady state and the transient performance are guaranteed to satisfy a prescribed performance requirement. Comparative experiments have been performed to test the effectiveness and to demonstrate the guaranteed performance of the proposed methods.

Low-Latency Telerobotics from Mars Orbit: The Case for Synergy Between Science and Human Exploration

NASA Technical Reports Server (NTRS)

Valinia, A.; Garvin, J. B.; Vondrak, R.; Thronson, H.; Lester, D.; Schmidt, G.; Fong, T.; Wilcox, B.; Sellers, P.; White, N.

2012-01-01

Initial, science-directed human exploration of Mars will benefit from capabilities in which human explorers remain in orbit to control telerobotic systems on the surface (Figure 1). Low-latency, high-bandwidth telerobotics (LLT) from Mars orbit offers opportunities for what the terrestrial robotics community considers to be high-quality telepresence. Such telepresence would provide high quality sensory perception and situation awareness, and even capabilities for dexterous manipulation as required for adaptive, informed selection of scientific samples [1]. Astronauts on orbit in close communication proximity to a surface exploration site (in order to minimize communication latency) represent a capability that would extend human cognition to Mars (and potentially for other bodies such as asteroids, Venus, the Moon, etc.) without the challenges, expense, and risk of putting those humans on hazardous surfaces or within deep gravity wells. Such a strategy may be consistent with goals for a human space flight program that, are currently being developed within NASA.

Executive Functions and the Improvement of Thinking Abilities: The Intervention in Reading Comprehension

PubMed Central

García-Madruga, Juan A.; Gómez-Veiga, Isabel; Vila, José Ó.

2016-01-01

In this paper, we propose a preliminary theory of executive functions that address in a specific way their relationship with working memory (WM) and higher-level cognition. It includes: (a) four core on-line WM executive functions that are involved in every novel and complex cognitive task; (b) two higher order off-line executive functions, planning and revision, that are required to resolving the most complex intellectual abilities; and (c) emotional control that is involved in any complex, novel and difficult task. The main assumption is that efficiency on thinking abilities may be improved by specific instruction or training on the executive functions necessary to solving novel and complex tasks involved in these abilities. Evidence for the impact of our training proposal on WM's executive functions involved in higher-level cognitive abilities comes from three studies applying an adaptive program designed to improve reading comprehension in primary school students by boosting the core WM's executive functions involved in it: focusing on relevant information, switching (or shifting) between representations or tasks, connecting incoming information from text with long-term representations, updating of the semantic representation of the text in WM, and inhibition of irrelevant information. The results are consistent with the assumption that cognitive enhancements from the training intervention may have affected not only a specific but also a more domain-general mechanism involved in various executive functions. We discuss some methodological issues in the studies of effects of WM training on reading comprehension. The perspectives and limitations of our approach are finally discussed. PMID:26869961

Intact short-term memory and impaired executive functions in obsessive compulsive disorder.

PubMed

Demeter, Gyula; Racsmány, Mihály; Csigó, Katalin; Harsányi, András; Németh, Attila; Döme, László

2013-01-30

Previous neuropsychological studies produced inconsistent results with tasks tapping short-term verbal and visual-spatial memory and executive functions in obsessive compulsive disorder (OCD). The aim of this study was to investigate the presence of deficits in these cognitive domains. A further goal was to describe the distribution of patients in different impairment ranges for all functions, and clarify the relationship between symptom severity and cognitive impairments. Thirty patients with OCD (DSM-IV) and 30 healthy volunteers were compared using well-known neuropsychological tasks. We assessed short-term verbal memory with the Digit Span Forward and Digit Span Backward Tasks, short-term visual-spatial memory with the Corsi Block Tapping Task, while we measured the level of executive functions with the StroopTask and the Wisconsin Card Sorting Test (WCST). Compared with a matched healthy control group, the performance of OCD patients was in the impaired range only in the two executive tasks. We find a significant positive correlations between the Y-BOCS (Yale-Brown Obsessive Compulsive Scale) total scores and the number of perseverative responses (r(28) = 0.409, p < 0.05) and perseverative errors (r(28) = 0.385, p < 0.05) in the WCST. Our results gave evidence that executive functions are impaired while short-term memory is intact in OCD. This is in line with neuropsychological model of OCD that the deficit of cognitive and behavioral inhibition are responsible for the main cognitive findings of this disorder, most prevalently the deficit in set shifting and prepotent response inhibition.

Applying an Integrative Framework of Executive Function to Preschoolers With Specific Language Impairment

PubMed Central

Plante, Elena; Doubleday, Kevin

2017-01-01

Purpose The first goal of this research was to compare verbal and nonverbal executive function abilities between preschoolers with and without specific language impairment (SLI). The second goal was to assess the group differences on 4 executive function components in order to determine if the components may be hierarchically related as suggested within a developmental integrative framework of executive function. Method This study included 26 4- and 5-year-olds diagnosed with SLI and 26 typically developing age- and sex-matched peers. Participants were tested on verbal and nonverbal measures of sustained selective attention, working memory, inhibition, and shifting. Results The SLI group performed worse compared with typically developing children on both verbal and nonverbal measures of sustained selective attention and working memory, the verbal inhibition task, and the nonverbal shifting task. Comparisons of standardized group differences between executive function measures revealed a linear increase with the following order: working memory, inhibition, shifting, and sustained selective attention. Conclusion The pattern of results suggests that preschoolers with SLI have deficits in executive functioning compared with typical peers, and deficits are not limited to verbal tasks. A significant linear relationship between group differences across executive function components supports the possibility of a hierarchical relationship between executive function skills. PMID:28724132

Effects of Mild Cognitive Impairment on the Event-Related Brain Potential Components Elicited in Executive Control Tasks.

PubMed

Zurrón, Montserrat; Lindín, Mónica; Cespón, Jesús; Cid-Fernández, Susana; Galdo-Álvarez, Santiago; Ramos-Goicoa, Marta; Díaz, Fernando

2018-01-01

We summarize here the findings of several studies in which we analyzed the event-related brain potentials (ERPs) elicited in participants with mild cognitive impairment (MCI) and in healthy controls during performance of executive tasks. The objective of these studies was to investigate the neural functioning associated with executive processes in MCI. With this aim, we recorded the brain electrical activity generated in response to stimuli in three executive control tasks (Stroop, Simon, and Go/NoGo) adapted for use with the ERP technique. We found that the latencies of the ERP components associated with the evaluation and categorization of the stimuli were longer in participants with amnestic MCI than in the paired controls, particularly those with multiple-domain amnestic MCI, and that the allocation of neural resources for attending to the stimuli was weaker in participants with amnestic MCI. The MCI participants also showed deficient functioning of the response selection and preparation processes demanded by each task.

Risk intelligence: making profit from uncertainty in data processing system.

PubMed

Zheng, Si; Liao, Xiangke; Liu, Xiaodong

2014-01-01

In extreme scale data processing systems, fault tolerance is an essential and indispensable part. Proactive fault tolerance scheme (such as the speculative execution in MapReduce framework) is introduced to dramatically improve the response time of job executions when the failure becomes a norm rather than an exception. Efficient proactive fault tolerance schemes require precise knowledge on the task executions, which has been an open challenge for decades. To well address the issue, in this paper we design and implement RiskI, a profile-based prediction algorithm in conjunction with a riskaware task assignment algorithm, to accelerate task executions, taking the uncertainty nature of tasks into account. Our design demonstrates that the nature uncertainty brings not only great challenges, but also new opportunities. With a careful design, we can benefit from such uncertainties. We implement the idea in Hadoop 0.21.0 systems and the experimental results show that, compared with the traditional LATE algorithm, the response time can be improved by 46% with the same system throughput.

Effects of Mild Cognitive Impairment on the Event-Related Brain Potential Components Elicited in Executive Control Tasks

PubMed Central

Zurrón, Montserrat; Lindín, Mónica; Cespón, Jesús; Cid-Fernández, Susana; Galdo-Álvarez, Santiago; Ramos-Goicoa, Marta; Díaz, Fernando

2018-01-01

We summarize here the findings of several studies in which we analyzed the event-related brain potentials (ERPs) elicited in participants with mild cognitive impairment (MCI) and in healthy controls during performance of executive tasks. The objective of these studies was to investigate the neural functioning associated with executive processes in MCI. With this aim, we recorded the brain electrical activity generated in response to stimuli in three executive control tasks (Stroop, Simon, and Go/NoGo) adapted for use with the ERP technique. We found that the latencies of the ERP components associated with the evaluation and categorization of the stimuli were longer in participants with amnestic MCI than in the paired controls, particularly those with multiple-domain amnestic MCI, and that the allocation of neural resources for attending to the stimuli was weaker in participants with amnestic MCI. The MCI participants also showed deficient functioning of the response selection and preparation processes demanded by each task.

Examining the development of attention and executive functions in children with a novel paradigm.

PubMed

Klimkeit, Ester I; Mattingley, Jason B; Sheppard, Dianne M; Farrow, Maree; Bradshaw, John L

2004-09-01

The development of attention and executive functions in normal children (7-12 years) was investigated using a novel selective reaching task, which involved reaching as rapidly as possible towards a target, while at times having to ignore a distractor. The information processing paradigm allowed the measurement of various distinct dimensions of behaviour within a single task. The largest improvements in vigilance, set-shifting, response inhibition, selective attention, and impulsive responding were observed to occur between the ages of 8 and 10, with a plateau in performance between 10 and 12 years of age. These findings, consistent with a step-wise model of development, coincide with the observed developmental spurt in frontal brain functions between 7 and 10 years of age, and indicate that attention and executive functions develop in parallel. This task appears to be a useful research tool in the assessment of attention and executive functions, within a single task. Thus it may have a role in determining which cognitive functions are most affected in different childhood disorders.

Risk Intelligence: Making Profit from Uncertainty in Data Processing System

PubMed Central

Liao, Xiangke; Liu, Xiaodong

2014-01-01

In extreme scale data processing systems, fault tolerance is an essential and indispensable part. Proactive fault tolerance scheme (such as the speculative execution in MapReduce framework) is introduced to dramatically improve the response time of job executions when the failure becomes a norm rather than an exception. Efficient proactive fault tolerance schemes require precise knowledge on the task executions, which has been an open challenge for decades. To well address the issue, in this paper we design and implement RiskI, a profile-based prediction algorithm in conjunction with a riskaware task assignment algorithm, to accelerate task executions, taking the uncertainty nature of tasks into account. Our design demonstrates that the nature uncertainty brings not only great challenges, but also new opportunities. With a careful design, we can benefit from such uncertainties. We implement the idea in Hadoop 0.21.0 systems and the experimental results show that, compared with the traditional LATE algorithm, the response time can be improved by 46% with the same system throughput. PMID:24883392

Happiness increases verbal and spatial working memory capacity where sadness does not: Emotion, working memory and executive control.

PubMed

Storbeck, Justin; Maswood, Raeya

2016-08-01

The effects of emotion on working memory and executive control are often studied in isolation. Positive mood enhances verbal and impairs spatial working memory, whereas negative mood enhances spatial and impairs verbal working memory. Moreover, positive mood enhances executive control, whereas negative mood has little influence. We examined how emotion influences verbal and spatial working memory capacity, which requires executive control to coordinate between holding information in working memory and completing a secondary task. We predicted that positive mood would improve both verbal and spatial working memory capacity because of its influence on executive control. Positive, negative and neutral moods were induced followed by completing a verbal (Experiment 1) or spatial (Experiment 2) working memory operation span task to assess working memory capacity. Positive mood enhanced working memory capacity irrespective of the working memory domain, whereas negative mood had no influence on performance. Thus, positive mood was more successful holding information in working memory while processing task-irrelevant information, suggesting that the influence mood has on executive control supersedes the independent effects mood has on domain-specific working memory.

A cognitive dual task affects gait variability in patients suffering from chronic low back pain.

PubMed

Hamacher, Dennis; Hamacher, Daniel; Schega, Lutz

2014-11-01

Chronic pain and gait variability in a dual-task situation are both associated with higher risk of falling. Executive functions regulate (dual-task) gait variability. A possible cause explaining why chronic pain increases risk of falling in an everyday dual-task situation might be that pain interferes with executive functions and results in a diminished dual-task capability with performance decrements on the secondary task. The main goal of this experiment was to evaluate the specific effects of a cognitive dual task on gait variability in chronic low back pain (CLBP) patients. Twelve healthy participants and twelve patients suffering from CLBP were included. The subjects were asked to perform a cognitive single task, a walking single task and a motor-cognitive dual task. Stride variability of trunk movements was calculated. A two-way ANOVA was performed to compare single-task walking with dual-task walking and the single cognitive task performance with the motor-cognitive dual-task performance. We did not find any differences in both of the single-task performances between groups. However, regarding single-task walking and dual-task walking, we observed an interaction effect indicating that low back pain patients show significantly higher gait variability in the dual-task condition as compared to controls. Our data suggest that chronic pain reduces motor-cognitive dual-task performance capability. We postulate that the detrimental effects are caused by central mechanisms where pain interferes with executive functions which, in turn, might contribute to increased risk of falling.

The cost of making an eye movement: A direct link between visual working memory and saccade execution.

PubMed

Schut, Martijn J; Van der Stoep, Nathan; Postma, Albert; Van der Stigchel, Stefan

2017-06-01

To facilitate visual continuity across eye movements, the visual system must presaccadically acquire information about the future foveal image. Previous studies have indicated that visual working memory (VWM) affects saccade execution. However, the reverse relation, the effect of saccade execution on VWM load is less clear. To investigate the causal link between saccade execution and VWM, we combined a VWM task and a saccade task. Participants were instructed to remember one, two, or three shapes and performed either a No Saccade-, a Single Saccade- or a Dual (corrective) Saccade-task. The results indicate that items stored in VWM are reported less accurately if a single saccade-or a dual saccade-task is performed next to retaining items in VWM. Importantly, the loss of response accuracy for items retained in VWM by performing a saccade was similar to committing an extra item to VWM. In a second experiment, we observed no cost of executing a saccade for auditory working memory performance, indicating that executing a saccade exclusively taxes the VWM system. Our results suggest that the visual system presaccadically stores the upcoming retinal image, which has a similar VWM load as committing one extra item to memory and interferes with stored VWM content. After the saccade, the visual system can retrieve this item from VWM to evaluate saccade accuracy. Our results support the idea that VWM is a system which is directly linked to saccade execution and promotes visual continuity across saccades.

Attentional impairments in Huntington's disease: A specific deficit for the executive conflict.

PubMed

Maurage, Pierre; Heeren, Alexandre; Lahaye, Magali; Jeanjean, Anne; Guettat, Lamia; Verellen-Dumoulin, Christine; Halkin, Stéphane; Billieux, Joël; Constant, Eric

2017-05-01

Huntington's disease (HD) is characterized by motor and cognitive impairments including memory, executive, and attentional functions. However, because earlier studies relied on multidetermined attentional tasks, uncertainty still abounds regarding the differential deficit across attentional subcomponents. Likewise, the evolution of these deficits during the successive stages of HD remains unclear. The present study simultaneously explored 3 distinct networks of attention (alerting, orienting, executive conflict) in preclinical and clinical HD. Thirty-eight HD patients (18 preclinical) and 38 matched healthy controls completed the attention network test, an integrated and theoretically grounded task assessing the integrity of 3 attentional networks. Preclinical HD was not characterized by any attentional deficit compared to controls. Conversely, clinical HD was associated with a differential deficit across the 3 attentional networks under investigation, showing preserved performance for alerting and orienting networks but massive and specific impairment for the executive conflict network. This indexes an impaired use of executive control to resolve the conflict between task-relevant stimuli and interfering task-irrelevant ones. Clinical HD does not lead to a global attentional deficit but rather to a specific impairment for the executive control of attention. Moreover, the absence of attentional deficits in preclinical HD suggests that these deficits are absent at the initial stages of the disease. In view of their impact on everyday life, attentional deficits should be considered in clinical contexts. Therapeutic programs improving the executive control of attention by neuropsychology and neuromodulation should be promoted. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Short-term memory, executive control, and children's route learning.

PubMed

Purser, Harry R M; Farran, Emily K; Courbois, Yannick; Lemahieu, Axelle; Mellier, Daniel; Sockeel, Pascal; Blades, Mark

2012-10-01

The aim of this study was to investigate route-learning ability in 67 children aged 5 to 11years and to relate route-learning performance to the components of Baddeley's model of working memory. Children carried out tasks that included measures of verbal and visuospatial short-term memory and executive control and also measures of verbal and visuospatial long-term memory; the route-learning task was conducted using a maze in a virtual environment. In contrast to previous research, correlations were found between both visuospatial and verbal memory tasks-the Corsi task, short-term pattern span, digit span, and visuospatial long-term memory-and route-learning performance. However, further analyses indicated that these relationships were mediated by executive control demands that were common to the tasks, with long-term memory explaining additional unique variance in route learning. Copyright © 2012 Elsevier Inc. All rights reserved.

Bilinguals Use Language-Control Brain Areas More Than Monolinguals to Perform Non-Linguistic Switching Tasks

PubMed Central

Rodríguez-Pujadas, Aina; Sanjuán, Ana; Ventura-Campos, Noelia; Román, Patricia; Martin, Clara; Barceló, Francisco; Costa, Albert; Ávila, César

2013-01-01

We tested the hypothesis that early bilinguals use language-control brain areas more than monolinguals when performing non-linguistic executive control tasks. We do so by exploring the brain activity of early bilinguals and monolinguals in a task-switching paradigm using an embedded critical trial design. Crucially, the task was designed such that the behavioural performance of the two groups was comparable, allowing then to have a safer comparison between the corresponding brain activity in the two groups. Despite the lack of behavioural differences between both groups, early bilinguals used language-control areas – such as left caudate, and left inferior and middle frontal gyri – more than monolinguals, when performing the switching task. Results offer direct support for the notion that, early bilingualism exerts an effect in the neural circuitry responsible for executive control. This effect partially involves the recruitment of brain areas involved in language control when performing domain-general executive control tasks, highlighting the cross-talk between these two domains. PMID:24058456

Monitored execution of robot plans produced by STRIPS.

NASA Technical Reports Server (NTRS)

Fikes, R. E.

1972-01-01

We describe PLANEX1, a plan executor for the Stanford Research Institute robot system. The problem-solving program STRIPS creates a plan consisting of a sequence of actions, and PLANEX1 program carries out the plan by executing the actions. PLANEX1 is designed so that it executes only that portion of the plan necessary for completing the task, reexecutes any portion of the plan that has failed to achieve the desired results, and initiates replanning in situations where the plan can no longer be effective in completing the task. The scenario for an example plan execution is given.

The Environment for Application Software Integration and Execution (EASIE) version 1.0. Volume 1: Executive overview

NASA Technical Reports Server (NTRS)

Rowell, Lawrence F.; Davis, John S.

1989-01-01

The Environment for Application Software Integration and Execution (EASIE) provides a methodology and a set of software utility programs to ease the task of coordinating engineering design and analysis codes. EASIE was designed to meet the needs of conceptual design engineers that face the task of integrating many stand-alone engineering analysis programs. Using EASIE, programs are integrated through a relational database management system. Volume 1, Executive Overview, gives an overview of the functions provided by EASIE and describes their use. Three operational design systems based upon the EASIE software are briefly described.

Combining Task Execution and Background Knowledge for the Verification of Medical Guidelines

NASA Astrophysics Data System (ADS)

Hommersom, Arjen; Groot, Perry; Lucas, Peter; Balser, Michael; Schmitt, Jonathan

The use of a medical guideline can be seen as the execution of computational tasks, sequentially or in parallel, in the face of patient data. It has been shown that many of such guidelines can be represented as a 'network of tasks', i.e., as a number of steps that have a specific function or goal. To investigate the quality of such guidelines we propose a formalization of criteria for good practice medicine a guideline should comply to. We use this theory in conjunction with medical background knowledge to verify the quality of a guideline dealing with diabetes mellitus type 2 using the interactive theorem prover KIV. Verification using task execution and background knowledge is a novel approach to quality checking of medical guidelines.

Functional connectivity of task context representations in prefrontal nodes of the multiple demand network.

PubMed

Stiers, Peter; Goulas, Alexandros

2018-06-01

A subset of regions in the lateral and medial prefrontal cortex and the anterior insula increase their activity level whenever a cognitive task becomes more demanding, regardless of the specific nature of this demand. During execution of a task, these areas and the surrounding cortex temporally encode aspects of the task context in spatially distributed patterns of activity. It is not clear whether these patterns reflect underlying anatomical subnetworks that still exist when task execution has finished. We use fMRI in 12 participants performing alternating blocks of three cognitive tasks to address this question. A first data set is used to define multiple demand regions in each participant. A second dataset from the same participants is used to determine multiple demand voxel assemblies with a preference for one task over the others. We then show that these voxels remain functionally coupled during execution of non-preferred tasks and that they exhibit stronger functional connectivity during rest. This indicates that the assemblies of task preference sharing voxels reflect patterns of underlying anatomical connections. Moreover, we show that voxels preferring the same task have more similar whole brain functional connectivity profiles that are consistent across participants. This suggests that voxel assemblies differ in patterns of input-output connections, most likely reflecting task demand-specific information exchange.

Representation and Analysis of Real-Time Control Structures.

DTIC Science & Technology

1980-08-01

external processes which cannot be forced to cooperate with programmed processes through use of a synchronization primitive such as a semaphore [Dijkstre...amounts to each task, but the time slices are synchronized with program execution. The length of the codestrip is determined by the response time...which might be synchronous or asynchronous with respect to the executing task. The notation can represent total and partial orderings among its tasks, and

Conducting the Train of Thought: Working Memory Capacity, Goal Neglect, and Mind Wandering in an Executive-Control Task

ERIC Educational Resources Information Center

McVay, Jennifer C.; Kane, Michael J.

2009-01-01

On the basis of the executive-attention theory of working memory capacity (WMC; e.g., M. J. Kane, A. R. A. Conway, D. Z. Hambrick, & R. W. Engle, 2007), the authors tested the relations among WMC, mind wandering, and goal neglect in a sustained attention to response task (SART; a go/no-go task). In 3 SART versions, making conceptual versus…

Brazilian adaptation of the Hotel Task: A tool for the ecological assessment of executive functions.

PubMed

Cardoso, Caroline de Oliveira; Zimmermann, Nicolle; Paraná, Camila Borges; Gindri, Gigiane; de Pereira, Ana Paula Almeida; Fonseca, Rochele Paz

2015-01-01

Over recent years, neuropsychological research has been increasingly concerned with the need to develop more ecologically valid instruments for the assessment of executive functions. The Hotel Task is one of the most widely used ecological measures of executive functioning, and provides an assessment of planning, organization, self-monitoring and cognitive flexibility. The goal of this study was to adapt the Hotel Task for use in the Brazilian population. The sample comprised 27 participants (three translators, six expert judges, seven healthy adults, ten patients with traumatic brain injuries and one hotel manager). The adaptation process consisted of five steps, which were repeated until a satisfactory version of the task was produced. The steps were as follows:(1) Translation;(2) Development of new stimuli and brainstorming among the authors;(3) Analysis by expert judges;(4) Pilot studies;(5) Assessment by an expert in business administration and hotel management. The adapted version proved adequate and valid for the assessment of executive functions. However, further research must be conducted to obtain evidence of the reliability, as well as the construct and criterion validity, sensitivity and specificity, of the Hotel Task. Many neurological and/or psychiatric populations may benefit from the adapted task, since it may make significant contributions to the assessment of dysexecutive syndromes and their impact on patient functioning.

On the Value of Estimating Human Arm Stiffness during Virtual Teleoperation with Robotic Manipulators

PubMed Central

Buzzi, Jacopo; Ferrigno, Giancarlo; Jansma, Joost M.; De Momi, Elena

2017-01-01

Teleoperated robotic systems are widely spreading in multiple different fields, from hazardous environments exploration to surgery. In teleoperation, users directly manipulate a master device to achieve task execution at the slave robot side; this interaction is fundamental to guarantee both system stability and task execution performance. In this work, we propose a non-disruptive method to study the arm endpoint stiffness. We evaluate how users exploit the kinetic redundancy of the arm to achieve stability and precision during the execution of different tasks with different master devices. Four users were asked to perform two planar trajectories following virtual tasks using both a serial and a parallel link master device. Users' arm kinematics and muscular activation were acquired and combined with a user-specific musculoskeletal model to estimate the joint stiffness. Using the arm kinematic Jacobian, the arm end-point stiffness was derived. The proposed non-disruptive method is capable of estimating the arm endpoint stiffness during the execution of virtual teleoperated tasks. The obtained results are in accordance with the existing literature in human motor control and show, throughout the tested trajectory, a modulation of the arm endpoint stiffness that is affected by task characteristics and hand speed and acceleration. PMID:29018319

Force related hemodynamic responses during execution and imagery of a hand grip task: A functional near infrared spectroscopy study.

PubMed

Wriessnegger, Selina C; Kirchmeyr, Daniela; Bauernfeind, Günther; Müller-Putz, Gernot R

2017-10-01

We examined force related hemodynamic changes during the performance of a motor execution (ME) and motor imagery (MI) task by means of multichannel functional near infrared spectroscopy (fNIRS). The hemodynamic responses of fourteen healthy participants were measured while they performed a hand grip execution or imagery task with low and high grip forces. We found an overall higher increase of [oxy-Hb] concentration changes during ME for both grip forces but with a delayed peak maximum for the lower grip force. During the MI task with lower grip force, the [oxy-Hb] level increases are stronger compared to the MI with higher grip force. The facilitation in performing MI with higher grip strength might thus indicate less inhibition of the actual motor act which could also explain the later increase onset of [oxy-Hb] in the ME task with the lower grip force. Our results suggest that execution and imagery of a hand grip task with high and low grip forces, leads to different cortical activation patterns. Since impaired control of grip forces during object manipulation in particular is one aspect of fine motor control deficits after stroke, our study will contribute to future rehabilitation programs enhancing patient's grip force control. Copyright © 2017 Elsevier Inc. All rights reserved.

Behavioral and Neural Correlates of Executive Function: Interplay between Inhibition and Updating Processes.

PubMed

Kim, Na Young; Wittenberg, Ellen; Nam, Chang S

2017-01-01

This study investigated the interaction between two executive function processes, inhibition and updating, through analyses of behavioral, neurophysiological, and effective connectivity metrics. Although, many studies have focused on behavioral effects of executive function processes individually, few studies have examined the dynamic causal interactions between these two functions. A total of twenty participants from a local university performed a dual task combing flanker and n-back experimental paradigms, and completed the Operation Span Task designed to measure working memory capacity. We found that both behavioral (accuracy and reaction time) and neurophysiological (P300 amplitude and alpha band power) metrics on the inhibition task (i.e., flanker task) were influenced by the updating load (n-back level) and modulated by working memory capacity. Using independent component analysis, source localization (DIPFIT), and Granger Causality analysis of the EEG time-series data, the present study demonstrated that manipulation of cognitive demand in a dual executive function task influenced the causal neural network. We compared connectivity across three updating loads (n-back levels) and found that experimental manipulation of working memory load enhanced causal connectivity of a large-scale neurocognitive network. This network contains the prefrontal and parietal cortices, which are associated with inhibition and updating executive function processes. This study has potential applications in human performance modeling and assessment of mental workload, such as the design of training materials and interfaces for those performing complex multitasking under stress.

Motor planning and execution in left- and right-handed individuals during a bimanual grasping and placing task.

PubMed

Hughes, Charmayne M L; Reissig, Paola; Seegelke, Christian

2011-09-01

The issue of handedness has been the topic of great interest for researchers in a number of scientific domains. It is typically observed that the dominant hand yields numerous behavioral advantages over the non-dominant hand during unimanual tasks, which provides evidence of hemispheric specialization. In contrast to advantages for the dominant hand during motor execution, recent research has demonstrated that the right hand has advantages during motor planning (regardless of handedness), indicating that motor planning is a specialized function of the left hemisphere. In the present study we explored hemispheric advantages in motor planning and execution in left- and right-handed individuals during a bimanual grasping and placing task. Replicating previous findings, both motor planning and execution was influenced by object end-orientation congruency. In addition, although motor planning (i.e., end-state comfort) was not influenced by hand or handedness, motor execution differed between left and right hand, with shorter object transport times observed for the left hand, regardless of handedness. These results demonstrate that the hemispheric advantages often observed in unimanual tasks do not extend to discrete bimanual tasks. We propose that the differences in object transport time between the two hands arise from overt shifting visual fixation between the two hands/objects. Copyright © 2011 Elsevier B.V. All rights reserved.

The effect of voice quality and competing speakers in a passage comprehension task: perceived effort in relation to cognitive functioning and performance in children with normal hearing.

PubMed

von Lochow, Heike; Lyberg-Åhlander, Viveka; Sahlén, Birgitta; Kastberg, Tobias; Brännström, K Jonas

2018-04-01

The study investigates the effect of voice quality and competing speakers on perceived effort in a passage comprehension task in relation to cognitive functioning. In addition, it explores if perceived effort was related to performance. A total of 49 children (aged 7:03 to 12:02 years) with normal hearing participated. The children performed an auditory passage comprehension task presented with six different listening conditions consisting of a typical voice or a dysphonic voice presented in quiet, with one competing speaker, and with four competing speakers. After completing the task, they rated their perceived effort on a five-grade scale. The children also performed tasks measuring working memory capacity (WMC) and executive functioning. The results show that voice quality had no direct effect on perceived effort but the children's ratings of perceived effort were related to their executive functioning. A significant effect was seen for background listening condition indicating higher perceived effort for background listening conditions with competing speakers. The effects of background listening condition were mainly related to the children's WMC but also their executive functioning. It can be concluded that the individual susceptibility to the effect of the dysphonic voice is related to the child's executive functioning. The individual susceptibility to the presence of competing speakers is related to the child's WMC and executive functioning.

Brain structure, executive function and appetitive traits in adolescent obesity.

PubMed

de Groot, C J; van den Akker, E L T; Rings, E H H M; Delemarre-van de Waal, H A; van der Grond, J

2017-08-01

Children with obesity show differences in brain structure, executive function and appetitive traits when compared with lean peers. Little is known on the relationship between brain structure and these traits. To investigate the relationship between differences in brain structure and executive function and appetitive traits, in obese and lean adolescents. MRI was used to measure cortical thickness and subcortical volumes. Executive function was measured by a Stop Signal-and a Choice Delay Task. Appetitive traits were measured using the Child Eating Behaviour Questionnaire. Adolescents with obesity had greater volumes of the pallidum; 1.78 mL (SE 0.03, p=0.014), when compared with controls; 1.65 mL (SE 0.02). In the group with obesity, greater pallidum volume was positively associated with the ability to delay reward in the Choice Delay Task (p=0.012). The association between pallidum volumes and Choice Delay Task in obese adolescents supports the hypothesis that the pallidum plays an important role in executive dysfunction in obese children. © 2016 World Obesity Federation.

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

PubMed

Brom, Sarah Susanne; Kliegel, Matthias

2014-09-01

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

Cognitive correlates of spatial navigation: Associations between executive functioning and the virtual Morris Water Task.

PubMed

Korthauer, L E; Nowak, N T; Frahmand, M; Driscoll, I

2017-01-15

Although effective spatial navigation requires memory for objects and locations, navigating a novel environment may also require considerable executive resources. The present study investigated associations between performance on the virtual Morris Water Task (vMWT), an analog version of a nonhuman spatial navigation task, and neuropsychological tests of executive functioning and spatial performance in 75 healthy young adults. More effective vMWT performance (e.g., lower latency and distance to reach hidden platform, greater distance in goal quadrant on a probe trial, fewer path intersections) was associated with better verbal fluency, set switching, response inhibition, and ability to mentally rotate objects. Findings also support a male advantage in spatial navigation, with sex moderating several associations between vMWT performance and executive abilities. Overall, we report a robust relationship between executive functioning and navigational skill, with some evidence that men and women may differentially recruit cognitive abilities when navigating a novel environment. Copyright © 2016 Elsevier B.V. All rights reserved.

Development and evaluation of a Fault-Tolerant Multiprocessor (FTMP) computer. Volume 2: FTMP software

NASA Technical Reports Server (NTRS)

Lala, J. H.; Smith, T. B., III

1983-01-01

The software developed for the Fault-Tolerant Multiprocessor (FTMP) is described. The FTMP executive is a timer-interrupt driven dispatcher that schedules iterative tasks which run at 3.125, 12.5, and 25 Hz. Major tasks which run under the executive include system configuration control, flight control, and display. The flight control task includes autopilot and autoland functions for a jet transport aircraft. System Displays include status displays of all hardware elements (processors, memories, I/O ports, buses), failure log displays showing transient and hard faults, and an autopilot display. All software is in a higher order language (AED, an ALGOL derivative). The executive is a fully distributed general purpose executive which automatically balances the load among available processor triads. Provisions for graceful performance degradation under processing overload are an integral part of the scheduling algorithms.

Effects of Alcohol on Tests of Executive Functioning in Men and Women: A Dose Response Examination

PubMed Central

Guillot, Casey R.; Fanning, Jennifer R.; Bullock, Joshua S.; McCloskey, Michael S.; Berman, Mitchell E.

2014-01-01

Alcohol has been shown to affect performance on tasks associated with executive functioning. However, studies in this area have generally been limited to a single dose or gender or have used small sample sizes. The purpose of this study was to provide a more nuanced and systematic examination of alcohol's effects on commonly used tests of executive functioning at multiple dosages in both men and women. Research volunteers (91 women and 94 men) were randomly assigned to one of four drink conditions (alcohol doses associated with target blood alcohol concentrations of .000%, .050%, .075% and .100%). Participants then completed three tasks comprising two domains of executive functioning: two set shifting tasks, the Trail Making Test and a computerized version of the Wisconsin Card Sorting Task, and a response inhibition task, the GoStop Impulsivity Paradigm. Impaired performance on set shifting tasks was found at the .100% and .075% dosages, but alcohol intoxication did not impair performance on the GoStop. No gender effects emerged. Thus, alcohol negatively affects set shifting at moderately high levels of intoxication in both men and women, likely due to alcohol's interference with prefrontal cortex function. Although it is well-established that alcohol negatively affects response inhibition as measured by auditory stop-signal tasks, alcohol does not appear to exert a negative effect on response inhibition as measured by the GoStop, a visual stop-signal task. PMID:20939644

A Telerobotic System for Transnasal Surgery

PubMed Central

Burgner, Jessica; Rucker, D. Caleb; Gilbert, Hunter B.; Swaney, Philip J.; Russell, Paul T.; Weaver, Kyle D.; Webster, Robert J.

2014-01-01

Mechanics-based models of concentric tube continuum robots have recently achieved a level of sophistication that makes it possible to begin to apply these robots to a variety of real-world clinical scenarios. Endonasal skull base surgery is one such application, where their small diameter and tentacle like dexterity are particularly advantageous. In this paper we provide the medical motivation for an endonasal surgical robot featuring concentric tube manipulators, and describe our model-based design and teleoperation methods, as well as a complete system incorporating image-guidance. Experimental demonstrations using a laparoscopic training task, a cadaver reachability study, and a phantom tumor resection experiment illustrate that both novice and expert users can effectively teleoperate the system, and that skull base surgeons can use the robot to achieve their objectives in a realistic surgical scenario. PMID:25089086

Universal computer control system (UCCS) for space telerobots

NASA Technical Reports Server (NTRS)

Bejczy, Antal K.; Szakaly, Zoltan

1987-01-01

A universal computer control system (UCCS) is under development for all motor elements of a space telerobot. The basic hardware architecture and software design of UCCS are described, together with the rich motor sensing, control, and self-test capabilities of this all-computerized motor control system. UCCS is integrated into a multibus computer environment with direct interface to higher level control processors, uses pulsewidth multiplier power amplifiers, and one unit can control up to sixteen different motors simultaneously at a high I/O rate. UCCS performance capabilities are illustrated by a few data.

The use of computer graphic simulation in the development of on-orbit tele-robotic systems

NASA Technical Reports Server (NTRS)

Fernandez, Ken; Hinman, Elaine

1987-01-01

This paper describes the use of computer graphic simulation techniques to resolve critical design and operational issues for robotic systems used for on-orbit operations. These issues are robot motion control, robot path-planning/verification, and robot dynamics. The major design issues in developing effective telerobotic systems are discussed, and the use of ROBOSIM, a NASA-developed computer graphic simulation tool, to address these issues is presented. Simulation plans for the Space Station and the Orbital Maneuvering Vehicle are presented and discussed.

Telerobotics: methodology for the development of through-the-Internet robotic teleoperated system

NASA Astrophysics Data System (ADS)

Alvares, Alberto J.; Caribe de Carvalho, Guilherme; Romariz, Luiz S. J.; Alfaro, Sadek C. A.

1999-11-01

This work presents a methodology for the development of Teleoperated Robotic System through Internet. Initially, it is presented a bibliographical review of the telerobotic systems that uses Internet as way of control. The methodology is implemented and tested through the development of two systems. The first is a manipulator with two degrees of freedom commanded remotely through Internet denominated RobWebCam. The second is a system which teleoperates an ABB (Asea Brown Boveri) Industrial Robot of six degrees of freedom denominated RobWebLink.

Visuo-Spatial Processing and Executive Functions in Children with Specific Language Impairment

ERIC Educational Resources Information Center

Marton, Klara

2008-01-01

Background: Individual differences in complex working memory tasks reflect simultaneous processing, executive functions, and attention control. Children with specific language impairment (SLI) show a deficit in verbal working memory tasks that involve simultaneous processing of information. Aims: The purpose of the study was to examine executive…

Preschool Executive Control on the Shape School Task: Measurement Considerations and Utility

ERIC Educational Resources Information Center

Pritchard, Verena E.; Woodward, Lianne J.

2011-01-01

Executive functions (EF) necessary for purposeful goal-directed activities undergo rapid change and development during the preschool years. However, of the few psychometrically valid measures of EF suitable for use with preschoolers, information on task sensitivity and predictive validity is scant. The neurodevelopmental correlates of early…

Resolving task rule incongruence during task switching by competitor rule suppression.

PubMed

Meiran, Nachshon; Hsieh, Shulan; Dimov, Eduard

2010-07-01

Task switching requires maintaining readiness to execute any task of a given set of tasks. However, when tasks switch, the readiness to execute the now-irrelevant task generates interference, as seen in the task rule incongruence effect. Overcoming such interference requires fine-tuned inhibition that impairs task readiness only minimally. In an experiment involving 2 object classification tasks and 2 location classification tasks, the authors show that irrelevant task rules that generate response conflicts are inhibited. This competitor rule suppression (CRS) is seen in response slowing in subsequent trials, when the competing rules become relevant. CRS is shown to operate on specific rules without affecting similar rules. CRS and backward inhibition, which is another inhibitory phenomenon, produced additive effects on reaction time, suggesting their mutual independence. Implications for current formal theories of task switching as well as for conflict monitoring theories are discussed. (c) 2010 APA, all rights reserved

Awareness of financial skills in dementia.

PubMed

Van Wielingen, L E; Tuokko, H A; Cramer, K; Mateer, C A; Hultsch, D F

2004-07-01

The present study examined the relations among levels of cognitive functioning, executive dysfunction, and awareness of financial management capabilities among a sample of 42 community-dwelling persons with dementia. Financial tasks on the Measure of Awareness of Financial Skills (MAFS) were dichotomized as simple or complex based on Piaget's operational levels of childhood cognitive development. Severity of global cognitive impairment and executive dysfunction were significantly related to awareness of financial abilities as measured by informant-participant discrepancy scores on the MAFS. For persons with mild and moderate/severe dementia, and persons with and without executive dysfunction, proportions of awareness within simple and complex financial task categories were tabulated. Significantly less awareness of financial abilities occurred on complex compared with simple tasks. Individuals with mild dementia were significantly less aware of abilities on complex items, whereas persons with moderate/severe dementia were less aware of abilities, regardless of task complexity. Similar patterns of awareness were observed for individuals with and without executive dysfunction. These findings support literature suggesting that deficits associated with dementia first occur for complex cognitive tasks involving inductive reasoning or decision-making in novel situations, and identify where loss of function in the financial domain may first be expected. Copyright Taylor & Francis Ltd

Visuo-spatial processing and executive functions in children with specific language impairment

PubMed Central

Marton, Klara

2007-01-01

Background Individual differences in complex working memory tasks reflect simultaneous processing, executive functions, and attention control. Children with specific language impairment (SLI) show a deficit in verbal working memory tasks that involve simultaneous processing of information. Aims The purpose of the study was to examine executive functions and visuo-spatial processing and working memory in children with SLI and in their typically developing peers (TLD). Experiment 1 included 40 children with SLI (age=5;3–6;10) and 40 children with TLD (age=5;3–6;7); Experiment 2 included 25 children with SLI (age=8;2–11;2) and 25 children with TLD (age=8;3–11;0). It was examined whether the difficulties that children with SLI show in verbal working memory tasks are also present in visuo-spatial working memory. Methods & Procedures In Experiment 1, children's performance was measured with three visuo-spatial processing tasks: space visualization, position in space, and design copying. The stimuli in Experiment 2 were two widely used neuropsychological tests: the Wisconsin Card Sorting Test — 64 (WCST-64) and the Tower of London test (TOL). Outcomes & Results In Experiment 1, children with SLI performed more poorly than their age-matched peers in all visuo-spatial working memory tasks. There was a subgroup within the SLI group that included children whose parents and teachers reported a weakness in the child's attention control. These children showed particular difficulties in the tasks of Experiment 1. The results support Engle's attention control theory: individuals need good attention control to perform well in visuo-spatial working memory tasks. In Experiment 2, the children with SLI produced more perseverative errors and more rule violations than their peers. Conclusions Executive functions have a great impact on SLI children's working memory performance, regardless of domain. Tasks that require an increased amount of attention control and executive functions are more difficult for the children with SLI than for their peers. Most children with SLI scored either below average or in the low average range on the neuropsychological tests that measured executive functions. PMID:17852522

A 24-Week Multi-Modality Exercise Program Improves Executive Control in Older Adults with a Self-Reported Cognitive Complaint: Evidence from the Antisaccade Task.

PubMed

Heath, Matthew; Shellington, Erin; Titheridge, Sam; Gill, Dawn P; Petrella, Robert J

2017-01-01

Exercise programs involving aerobic and resistance training (i.e., multiple-modality) have shown promise in improving cognition and executive control in older adults at risk, or experiencing, cognitive decline. It is, however, unclear whether cognitive training within a multiple-modality program elicits an additive benefit to executive/cognitive processes. This is an important question to resolve in order to identify optimal training programs that delay, or ameliorate, executive deficits in persons at risk for further cognitive decline. In the present study, individuals with a self-reported cognitive complaint (SCC) participated in a 24-week multiple-modality (i.e., the M2 group) exercise intervention program. In addition, a separate group of individuals with a SCC completed the same aerobic and resistance training as the M2 group but also completed a cognitive-based stepping task (i.e., multiple-modality, mind-motor intervention: M4 group). Notably, pre- and post-intervention executive control was examined via the antisaccade task (i.e., eye movement mirror-symmetrical to a target). Antisaccades are an ideal tool for the study of individuals with subtle executive deficits because of its hands- and language-free nature and because the task's neural mechanisms are linked to neuropathology in cognitive decline (i.e., prefrontal cortex). Results showed that M2 and M4 group antisaccade reaction times reliably decreased from pre- to post-intervention and the magnitude of the decrease was consistent across groups. Thus, multi-modality exercise training improved executive performance in persons with a SCC independent of mind-motor training. Accordingly, we propose that multiple-modality training provides a sufficient intervention to improve executive control in persons with a SCC.

Monitoring supports performance in a dual-task paradigm involving a risky decision-making task and a working memory task

PubMed Central

Gathmann, Bettina; Schiebener, Johannes; Wolf, Oliver T.; Brand, Matthias

2015-01-01

Performing two cognitively demanding tasks at the same time is known to decrease performance. The current study investigates the underlying executive functions of a dual-tasking situation involving the simultaneous performance of decision making under explicit risk and a working memory task. It is suggested that making a decision and performing a working memory task at the same time should particularly require monitoring—an executive control process supervising behavior and the state of processing on two tasks. To test the role of a supervisory/monitoring function in such a dual-tasking situation we investigated 122 participants with the Game of Dice Task plus 2-back task (GDT plus 2-back task). This dual task requires participants to make decisions under risk and to perform a 2-back working memory task at the same time. Furthermore, a task measuring a set of several executive functions gathered in the term concept formation (Modified Card Sorting Test, MCST) and the newly developed Balanced Switching Task (BST), measuring monitoring in particular, were used. The results demonstrate that concept formation and monitoring are involved in the simultaneous performance of decision making under risk and a working memory task. In particular, the mediation analysis revealed that BST performance partially mediates the influence of MCST performance on the GDT plus 2-back task. These findings suggest that monitoring is one important subfunction for superior performance in a dual-tasking situation including decision making under risk and a working memory task. PMID:25741308

Hand specific representations in language comprehension.

PubMed

Moody-Triantis, Claire; Humphreys, Gina F; Gennari, Silvia P

2014-01-01

Theories of embodied cognition argue that language comprehension involves sensory-motor re-enactments of the actions described. However, the degree of specificity of these re-enactments as well as the relationship between action and language remains a matter of debate. Here we investigate these issues by examining how hand-specific information (left or right hand) is recruited in language comprehension and action execution. An fMRI study tested self-reported right-handed participants in two separate tasks that were designed to be as similar as possible to increase sensitivity of the comparison across task: an action execution go/no-go task where participants performed right or left hand actions, and a language task where participants read sentences describing the same left or right handed actions as in the execution task. We found that language-induced activity did not match the hand-specific patterns of activity found for action execution in primary somatosensory and motor cortex, but it overlapped with pre-motor and parietal regions associated with action planning. Within these pre-motor regions, both right hand actions and sentences elicited stronger activity than left hand actions and sentences-a dominant hand effect. Importantly, both dorsal and ventral sections of the left pre-central gyrus were recruited by both tasks, suggesting different action features being recruited. These results suggest that (a) language comprehension elicits motor representations that are hand-specific and akin to multimodal action plans, rather than full action re-enactments; and (b) language comprehension and action execution share schematic hand-specific representations that are richer for the dominant hand, and thus linked to previous motor experience.

Altered neural circuits accompany lower performance during narrative comprehension in children with reading difficulties: an fMRI study.

PubMed

Horowitz-Kraus, Tzipi; Buck, Catherine; Dorrmann, Dana

2016-10-01

Narrative comprehension is a linguistic ability that is foundational for future reading ability. The aim of the current study was to examine the neural circuitry of children with reading difficulties (RD) compared to typical readers during a narrative-comprehension task. We hypothesized that due to deficient executive functions, which support narrative comprehension abilities, children with RD would display altered activation and functional connectivity, as well as lower performance on a narrative-comprehension task. Children with RD and typical readers were scanned during a narrative-comprehension task and administered reading behavioral tests. Children with RD scored significantly lower on the narrative-comprehension task than did typical readers. Composite activation maps showed more diffused activation during narrative comprehension in the RD group. Maps comparing the two reading groups showed more activation in the frontal lobes (regions responsible for executive functions), and functional connectivity showed higher global efficiency in children with RD than in typical readers. Global efficiency was negatively correlated with phonological awareness and reading and executive function scores in the entire study group. Children with RD may suffer from narrative-comprehension difficulties due to diffused activation of language areas, as was observed during a narrative-comprehension task. Greater effort in this task may be reflected by the engagement of brain regions related to executive functions and higher functional connectivity or attributed to difficulties in phonological processing and reading and executive functions. Therefore, the accommodation given to children with RD of reading aloud may need to be revised due to the observed difficulty in this domain.

Goal Management Training and Mindfulness Meditation improve executive functions and transfer to ecological tasks of daily life in polysubstance users enrolled in therapeutic community treatment.

PubMed

Valls-Serrano, Carlos; Caracuel, Alfonso; Verdejo-Garcia, Antonio

2016-08-01

We have previously shown that Goal Management Training+Mindfulness Meditation (GMT+MM) improves executive functions in polysubstance users enrolled in outpatient treatment. The aim of this study was to establish if GMT+MM has similar positive effects on executive functions in polysubstance users in residential treatment, and if executive functions' gains transfer to more ecologically valid goal-oriented tasks. Thirty-two polysbustance users were randomly allocated to eight weeks of GMT+MM (n=16) or control, i.e., no-intervention (n=16); both groups received treatment as usual. Outcome measures included performance in laboratory tasks of basic and complex executive functions (i.e., basic: working memory and inhibition; complex: planning and self-regulation) and in an ecological task of goal-directed behavior (the Multiple Errands Test - contextualized version, MET-CV) measured post-interventions. Results showed that GMT+MM was superior to control in improving basic measures of working memory (Letter-number sequencing; F=4.516, p=0.049) and reflection impulsivity (Information Sampling Test; F=6.217, p=0.018), along with initial thinking times during planning (Zoo Map Test; F=8.143, p=0.008). In addition, GMT+MM was superior to control in improving performance in the MET-CV (task failures; F=8.485, p=0.007). Our findings demonstrate that GMT+MM increases reflective processes and the achievement of goals in daily activities, furthermore ecological test can detects changes easily than laboratory tasks. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The Effects of Multimodal Mobile Communications on Cooperative Team Interactions Executing Distributed Tasks

DTIC Science & Technology

2013-07-01

AFRL-RH-WP-TP-2013-0046 The Effects of Multimodal Mobile Communications on Cooperative Team Interactions Executing Distributed Tasks Gregory...3. DATES COVERED (From - To) 31-07-13 Interim 01 August 2011 – 01 August 2013 4. TITLE AND SUBTITLE The Effects of Multimodal Mobile... multimodal communication capabilities can con- tribute to the effectiveness and efficiency of real-time, task outcome and per- formance. In this paper, we

Switching between simple cognitive tasks: the interaction of top-down and bottom-up factors

NASA Technical Reports Server (NTRS)

Ruthruff, E.; Remington, R. W.; Johnston, J. C.

2001-01-01

How do top-down factors (e.g., task expectancy) and bottom-up factors (e.g., task recency) interact to produce an overall level of task readiness? This question was addressed by factorially manipulating task expectancy and task repetition in a task-switching paradigm. The effects of expectancy and repetition on response time tended to interact underadditively, but only because the traditional binary task-repetition variable lumps together all switch trials, ignoring variation in task lag. When the task-recency variable was scaled continuously, all 4 experiments instead showed additivity between expectancy and recency. The results indicated that expectancy and recency influence different stages of mental processing. One specific possibility (the configuration-execution model) is that task expectancy affects the time required to configure upcoming central operations, whereas task recency affects the time required to actually execute those central operations.

Improved Cognition While Cycling in Parkinson’s Disease Patients and Healthy Adults

PubMed Central

Hazamy, Audrey A.; Altmann, Lori J. P.; Stegemöller, Elizabeth; Bowers, Dawn; Lee, Hyo Keun; Wilson, Jonathan; Okun, Michael S.; Hass, Chris J.

2017-01-01

Persons with Parkinson’s disease (PD) are typically more susceptible than healthy adults to impaired performance when two tasks (dual task interference) are performed simultaneously. This limitation has by many experts been attributed to limitations in cognitive resources. Nearly all studies of dual task performance in PD employ walking or balance-based motor tasks, which are commonly impaired in PD. These tasks can be performed using a combination of one or two executive function tasks. The current study examined whether persons with PD would demonstrate greater dual task effects on cognition compared to healthy older adults (HOAs) during a concurrent cycling task. Participants with and without PD completed a battery of 12 cognitive tasks assessing visual and verbal processing in the following cognitive domains: speed of processing, controlled processing, working memory and executive function. Persons with PD exhibited impairments compared to healthy participants in select tasks (i.e., 0-Back, 2-Back and operation span). Further, both groups unexpectedly exhibited dual task facilitation of response times in visual tasks across cognitive domains, and improved verbal recall during an executive function task. Only one measure, 2-back, showed a speed-accuracy trade-off in the dual task. These results demonstrate that, when paired with a motor task in which they are not impaired, people with PD exhibit similar dual task effects on cognitive tasks as HOAs, even when these dual task effects are facilitative. More generally, these findings demonstrate that pairing cognitive tasks with cycling may actually improve cognitive performance which may have therapeutic relevance to cognitive decline associated with aging and PD pathology. PMID:28088064

Heart rate variability and cognitive processing: The autonomic response to task demands.

PubMed

Luque-Casado, Antonio; Perales, José C; Cárdenas, David; Sanabria, Daniel

2016-01-01

This study investigated variations in heart rate variability (HRV) as a function of cognitive demands. Participants completed an execution condition including the psychomotor vigilance task, a working memory task and a duration discrimination task. The control condition consisted of oddball versions (participants had to detect the rare event) of the tasks from the execution condition, designed to control for the effect of the task parameters (stimulus duration and stimulus rate) on HRV. The NASA-TLX questionnaire was used as a subjective measure of cognitive workload across tasks and conditions. Three major findings emerged from this study. First, HRV varied as a function of task demands (with the lowest values in the working memory task). Second, and crucially, we found similar HRV values when comparing each of the tasks with its oddball control equivalent, and a significant decrement in HRV as a function of time-on-task. Finally, the NASA-TLX results showed larger cognitive workload in the execution condition than in the oddball control condition, and scores variations as a function of task. Taken together, our results suggest that HRV is highly sensitive to overall demands of sustained attention over and above the influence of other cognitive processes suggested by previous literature. In addition, our study highlights a potential dissociation between objective and subjective measures of mental workload, with important implications in applied settings. Copyright © 2015 Elsevier B.V. All rights reserved.

Emotion suppression moderates the quadratic association between RSA and executive function

PubMed Central

Spangler, Derek P.; Bell, Martha Ann; Deater-Deckard, Kirby

2016-01-01

There is uncertainty about whether respiratory sinus arrhythmia (RSA), a cardiac marker of adaptive emotion regulation, is involved in relatively low or high executive function performance. In the present study, we investigated: (1) whether RSA during rest and tasks predict both relatively low and high executive function within a larger quadratic association among the two variables, and (2) the extent to which this quadratic trend was moderated by individual differences in emotion regulation. To achieve these aims, a sample of ethnically and socioeconomically diverse women self-reported reappraisal and emotion suppression. They next experienced a two-minute resting period during which ECG was continually assessed. In the next phase, the women completed an array of executive function and non-executive cognitive tasks while ECG was measured throughout. As anticipated, resting RSA showed a quadratic association with executive function that was strongest for high suppression. These results suggest that relatively high resting RSA may predict poor executive function ability when emotion regulation consumes executive control resources needed for ongoing cognitive performance. PMID:26018941

Executive functioning impairment in women treated with chemotherapy for breast cancer: a systematic review.

PubMed

Yao, Christie; Bernstein, Lori J; Rich, Jill B

2017-11-01

Women with breast cancer have reported adverse cognitive effects following chemotherapy. Evidence is mixed on whether executive functioning is particularly impaired in women treated with chemotherapy, in part due to the wide range of tasks used to measure executive processes. We performed a systematic review of the published literature to evaluate whether some subcomponents of executive functioning are more vulnerable to impairment than others among breast cancer survivors who had been treated with chemotherapy. Studies published as of April 2017 were identified using three electronic databases (MEDLINE, PsycINFO, and Web of Science) and a manual search of relevant reference lists. The methodological quality of included studies was assessed using a checklist of predefined criteria. Of 1280 identified articles, a total of 41 were included for review. Study findings were categorized into three primary subdomains of executive functioning: inhibition, shifting, and updating. Although there was heterogeneity in the neuropsychological measures used to assess executive functioning, tests could be grouped into the subcomponents they assessed. Inhibition appears relatively spared from the effects of chemotherapy, whereas impairments in shifting and updating are more commonly found following chemotherapy. Examination of subcomponents of executive functioning is recommended to better characterize the nature of executive dysfunction in women treated with chemotherapy. Future studies should include executive functioning tasks of varying complexity, use of multiple tasks to increase reliability, and alternative indices to capture performance, such as within-person variability.

Individual Differences In The Executive Control Of Attention, Memory, And Thought, And Their Associations With Schizotypy

PubMed Central

Kane, Michael J.; Meier, Matt E.; Smeekens, Bridget A.; Gross, Georgina M.; Chun, Charlotte A.; Silvia, Paul J.; Kwapil, Thomas R.

2016-01-01

A large correlational study took a latent-variable approach to the generality of executive control by testing the individual-differences structure of executive-attention capabilities and assessing their prediction of schizotypy, a multidimensional construct (with negative, positive, disorganized, and paranoid factors) conveying risk for schizophrenia. Although schizophrenia is convincingly linked to executive deficits, the schizotypy literature is equivocal. Subjects completed tasks of working memory capacity (WMC), attention restraint (inhibiting prepotent responses), and attention constraint (focusing visual attention amid distractors), the latter two in an effort to fractionate the “inhibition” construct. We also assessed mind-wandering propensity (via in-task thought probes) and coefficient of variation in response times (RT CoV) from several tasks as more novel indices of executive attention. WMC, attention restraint, attention constraint, mind wandering, and RT CoV were correlated but separable constructs, indicating some distinctions among “attention control” abilities; WMC correlated more strongly with attentional restraint than constraint, and mind wandering correlated more strongly with attentional restraint, attentional constraint, and RT CoV than with WMC. Across structural models, no executive construct predicted negative schizotypy and only mind wandering and RT CoV consistently (but modestly) predicted positive, disorganized, and paranoid schizotypy; stalwart executive constructs in the schizophrenia literature — WMC and attention restraint — showed little to no predictive power, beyond restraint’s prediction of paranoia. Either executive deficits are consequences rather than risk factors for schizophrenia, or executive failures barely precede or precipitate diagnosable schizophrenia symptoms. PMID:27454042

Executive function processes predict mobility outcomes in older adults.

PubMed

Gothe, Neha P; Fanning, Jason; Awick, Elizabeth; Chung, David; Wójcicki, Thomas R; Olson, Erin A; Mullen, Sean P; Voss, Michelle; Erickson, Kirk I; Kramer, Arthur F; McAuley, Edward

2014-02-01

To examine the relationship between performance on executive function measures and subsequent mobility outcomes in community-dwelling older adults. Randomized controlled clinical trial. Champaign-Urbana, Illinois. Community-dwelling older adults (N = 179; mean age 66.4). A 12-month exercise trial with two arms: an aerobic exercise group and a stretching and strengthening group. Established cognitive tests of executive function (flanker task, task switching, and a dual-task paradigm) and the Wisconsin card sort test. Mobility was assessed using the timed 8-foot up and go test and times to climb up and down a flight of stairs. Participants completed the cognitive tests at baseline and the mobility measures at baseline and after 12 months of the intervention. Multiple regression analyses were conducted to determine whether baseline executive function predicted postintervention functional performance after controlling for age, sex, education, cardiorespiratory fitness, and baseline mobility levels. Selective baseline executive function measurements, particularly performance on the flanker task (β = 0.15-0.17) and the Wisconsin card sort test (β = 0.11-0.16) consistently predicted mobility outcomes at 12 months. The estimates were in the expected direction, such that better baseline performance on the executive function measures predicted better performance on the timed mobility tests independent of intervention. Executive functions of inhibitory control, mental set shifting, and attentional flexibility were predictive of functional mobility. Given the literature associating mobility limitations with disability, morbidity, and mortality, these results are important for understanding the antecedents to poor mobility function that well-designed interventions to improve cognitive performance can attenuate. © 2014, Copyright the Authors Journal compilation © 2014, The American Geriatrics Society.

Iowa Gambling Task performance and emotional distress interact to predict risky sexual behavior in individuals with dual substance and HIV diagnoses

PubMed Central

Wardle, Margaret C.; Gonzalez, Raul; Bechara, Antoine; Martin-Thormeyer, Eileen M.

2013-01-01

HIV+ substance-dependent individuals (SDIs) show emotional distress and executive impairment, but in isolation these poorly predict sexual risk. We hypothesized that an executive measure sensitive to emotional aspects of judgment (Iowa Gambling Task; IGT) would identify HIV+ SDIs whose sexual risks were influenced by emotional distress. We assessed emotional distress and performance on several executive tasks in 190 HIV+ SDIs. IGT performance interacted significantly with emotional distress, such that only in better performers were distress and risk related. Our results are interpreted using the somatic marker hypothesis and indicate that the IGT identifies HIV+ SDIs for whom psychological distress influences HIV risk. PMID:20480423

Central as well as Peripheral Attentional Bottlenecks in Dual-Task Performance Activate Lateral Prefrontal Cortices

PubMed Central

Szameitat, André J.; Vanloo, Azonya; Müller, Hermann J.

2016-01-01

Human information processing suffers from severe limitations in parallel processing. In particular, when required to respond to two stimuli in rapid succession, processing bottlenecks may appear at central and peripheral stages of task processing. Importantly, it has been suggested that executive functions are needed to resolve the interference arising at such bottlenecks. The aims of the present study were to test whether central attentional limitations (i.e., bottleneck at the decisional response selection stage) as well as peripheral limitations (i.e., bottleneck at response initiation) both demand executive functions located in the lateral prefrontal cortex. For this, we re-analyzed two previous studies, in which a total of 33 participants performed a dual-task according to the paradigm of the psychological refractory period (PRP) during functional magnetic resonance imaging (fMRI). In one study (N = 17), the PRP task consisted of two two-choice response tasks known to suffer from a central bottleneck (CB group). In the other study (N = 16), the PRP task consisted of two simple-response tasks known to suffer from a peripheral bottleneck (PB group). Both groups showed considerable dual-task costs in form of slowing of the second response in the dual-task (PRP effect). Imaging results are based on the subtraction of both single-tasks from the dual-task within each group. In the CB group, the bilateral middle frontal gyri and inferior frontal gyri were activated. Higher activation in these areas was associated with lower dual-task costs. In the PB group, the right middle frontal and inferior frontal gyrus (IFG) were activated. Here, higher activation was associated with higher dual-task costs. In conclusion we suggest that central and peripheral bottlenecks both demand executive functions located in lateral prefrontal cortices (LPFC). Differences between the CB and PB groups with respect to the exact prefrontal areas activated and the correlational patterns suggest that the executive functions resolving interference at least partially differ between the groups. PMID:27014044

Linking Executive Function and Peer Problems from Early Childhood Through Middle Adolescence.

PubMed

Holmes, Christopher J; Kim-Spoon, Jungmeen; Deater-Deckard, Kirby

2016-01-01

Peer interactions and executive function play central roles in the development of healthy children, as peer problems have been indicative of lower cognitive competencies such as self-regulatory behavior and poor executive function has been indicative of problem behaviors and social dysfunction. However, few studies have focused on the relation between peer interactions and executive function and the underlying mechanisms that may create this link. Using a national sample (n = 1164, 48.6% female) from the Study of Early Child Care and Youth Development (SECCYD), we analyzed executive function and peer problems (including victimization and rejection) across three waves within each domain (executive function or peer problems), beginning in early childhood and ending in middle adolescence. Executive function was measured as a multi-method, multi-informant composite including reports from parents on the Children's Behavior Questionnaire and Child Behavior Checklist and child's performance on behavioral tasks including the Continuous Performance Task, Woodcock-Johnson, Tower of Hanoi, Operation Span Task, Stroop, and Tower of London. Peer problems were measured as a multi-informant composite including self, teacher, and afterschool caregiver reports on multiple peer-relationship scales. Using a cross-lagged design, our Structural Equation Modeling findings suggested that experiencing peer problems contributed to lower executive function later in childhood and better executive function reduced the likelihood of experiencing peer problems later in childhood and middle adolescence, although these relations weakened as a child moves into adolescence. The results highlight that peer relationships are involved in the development of strengths and deficits in executive function and vice versa.

Linking Executive Function and Peer Problems from Early Childhood through Middle Adolescence

PubMed Central

Holmes, Christopher J.; Kim-Spoon, Jungmeen; Deater-Deckard, Kirby

2015-01-01

Peer interactions and executive function play central roles in the development of healthy children, as peer problems have been indicative of lower cognitive competencies such as self-regulatory behavior and poor executive function has been indicative of problem behaviors and social dysfunction. However, few studies have focused on the relation between peer interactions and executive function and the underlying mechanisms that may create this link. Using a national sample (n = 1,164, 48.6% female) from the Study of Early Child Care and Youth Development (SECCYD), we analyzed executive function and peer problems (including victimization and rejection) across three waves within each domain (executive function or peer problems), beginning in early childhood and ending in middle adolescence. Executive function was measured as a multi-method, multi-informant composite including reports from parents on the Children’s Behavior Questionnaire and Child Behavior Checklist and child’s performance on behavioral tasks including the Continuous Performance Task, Woodcock-Johnson, Tower of Hanoi, Operation Span Task, Stroop, and Tower of London. Peer problems were measured as a multi-informant composite including self, teacher, and after school caregiver reports on multiple peer-relationship scales. Using a cross-lagged design, our Structural Equation Modeling findings suggested that experiencing peer problems contributed to lower executive function later in childhood and better executive function reduced the likelihood of experiencing peer problems later in childhood and middle adolescence, although these relations weakened as a child moves into adolescence. The results highlight that peer relationships are involved in the development of strengths and deficits in executive function and vice versa. PMID:26096194

Acute stress affects prospective memory functions via associative memory processes.

PubMed

Szőllősi, Ágnes; Pajkossy, Péter; Demeter, Gyula; Kéri, Szabolcs; Racsmány, Mihály

2018-01-01

Recent findings suggest that acute stress can improve the execution of delayed intentions (prospective memory, PM). However, it is unclear whether this improvement can be explained by altered executive control processes or by altered associative memory functioning. To investigate this issue, we used physical-psychosocial stressors to induce acute stress in laboratory settings. Then participants completed event- and time-based PM tasks requiring the different contribution of control processes and a control task (letter fluency) frequently used to measure executive functions. According to our results, acute stress had no impact on ongoing task performance, time-based PM, and verbal fluency, whereas it enhanced event-based PM as measured by response speed for the prospective cues. Our findings indicate that, here, acute stress did not affect executive control processes. We suggest that stress affected event-based PM via associative memory processes. Copyright © 2017 Elsevier B.V. All rights reserved.

Executive functions in men and postmenopausal women.

PubMed

Castonguay, Nathalie; Lussier, Maxime; Bugaiska, Aurélia; Lord, Catherine; Bherer, Louis

2015-01-01

This study was designed to assess sex differences in older adults (55-65 years old) in executive functions and to examine the influence of hormone therapy (HT) in postmenopausal women. We have assessed task performance in memory, visuospatial, and executive functions in 29 women using HT, 29 women who never used HT, and 30 men. Men outperformed never users in task switching and updating. HT users outperformed never users in updating. HT users outperformed never users and men in visual divided attention. The present study support previous findings that sex and HT impact cognition and bring new insights on sex and HT-related differences in executive functions.

Systematic behavioural observation of executive performance after brain injury.

PubMed

Lewis, Mark W; Babbage, Duncan R; Leathem, Janet M

2017-01-01

To develop an ecologically valid measure of executive functioning (i.e. Planning and Organization, Executive Memory, Initiation, Cognitive Shifting, Impulsivity, Sustained and Directed Attention, Error Detection, Error Correction and Time Management) during a functional chocolate brownie cooking task. In Study 1, the inter-rater reliability of a novel behavioural observation assessment method was assessed with 10 people with traumatic brain injury (TBI). In Study 2, 27 people with TBI and 16 healthy controls completed the functional task along with other measures of executive functioning to assess validity. Intraclass correlation coefficients for six of the nine aspects of executive functioning ranged from .54 to 1.00. Percentage agreements for the remaining aspects ranged from 70% to 90%. Significant and non-significant, moderate, correlations were found between the functional cooking task and standard neuropsychological measures. The healthy control group performed better than the TBI group in six areas (d = 0.56 to 1.23). In this initial trial of a novel assessment method, adequate inter-rater reliability was found. The measure was associated with standard neuropsychological measures, and our healthy control group performed better than the TBI group. The measure appears to be an ecologically valid measure of executive functioning.

Social cognition dysfunction in adolescents with 22q11.2 deletion syndrome (velo-cardio-facial syndrome): relationship with executive functioning and social competence/functioning.

PubMed

Campbell, L E; McCabe, K L; Melville, J L; Strutt, P A; Schall, U

2015-09-01

Social difficulties are often noted among people with intellectual disabilities. Children and adults with 22q.11.2 deletion syndrome (22q11DS) often have poorer social competence as well as poorer performance on measures of executive and social-cognitive skills compared with typically developing young people. However, the relationship between social functioning and more basic processes of social cognition and executive functioning are not well understood in 22q11DS. The present study examined the relationship between social-cognitive measures of emotion attribution and theory of mind with executive functioning and their contribution to social competence in 22q11DS. The present cross-sectional study measured social cognition and executive performance of 24 adolescents with 22q11DS compared with 27 age-matched typically developing controls. Social cognition was tested using the emotion attribution task (EAT) and a picture sequencing task (PST), which tested mentalising (false-belief), sequencing, cause and effect, and inhibition. Executive functioning was assessed using computerised versions of the Tower of London task and working memory measures of spatial and non-spatial ability. Social competence was also assessed using the parent-reported Strengths and Difficulties Questionnaire. Adolescents with 22q11DS showed impaired false-belief, emotion attribution and executive functioning compared with typically developing control participants. Poorer performance was reported on all story types in the PST, although, patterns of errors and response times across story types were similar in both groups. General sequencing ability was the strongest predictor of false-belief, and performance on the false-belief task predicted emotion attribution accuracy. Intellectual functioning, rather than theory of mind or executive functioning, predicted social competence in 22q11DS. Performance on social-cognitive tasks of theory of mind indicate evidence of a general underlying dysfunction in 22q11DS that includes executive ability to understand cause and effect, to logically reason about social scenarios and also to inhibit responses to salient, but misleading cues. However, general intellectual ability is closely related to actual social competence suggesting that a generalised intellectual deficit coupled with more specific executive impairments may best explain poor social cognition in 22q11DS. © 2015 MENCAP and International Association of the Scientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd.

Formative versus Reflective Measurement of Executive Function Tasks: Response to Commentaries and Another Perspective

ERIC Educational Resources Information Center

Willoughby, Michael T.

2014-01-01

The focus article (Willoughby et al., 2014) (1) introduced the distinction between formative and reflective measurement and (2) proposed that performance-based executive function tasks may be better conceptualized from the perspective of formative rather than reflective measurement. This proposal stands in sharp contrast to conventional…

Executive Function: Comparing Bilingual and Monolingual Iranian University Students

ERIC Educational Resources Information Center

Kazemeini, Toktam; Fadardi, Javad Salehi

2016-01-01

The study aimed to examine whether Kurdish-Persian early Bilingual university students (EBL) and Persian Monolingual university students (ML) differ on tasks of executive function (EF). Thirty male EBL and 30 male ML students from Ferdowsi University of Mashhad completed a Persian Stroop Color-Word task (SCWT), Backward Digit Span Test (BDST),…

The Source of Execution-Related Dual-Task Interference: Motor Bottleneck or Response Monitoring?

ERIC Educational Resources Information Center

Bratzke, Daniel; Rolke, Bettina; Ulrich, Rolf

2009-01-01

The present study assessed the underlying mechanism of execution-related dual-task interference in the psychological refractory period (PRP) paradigm. The motor bottleneck hypothesis attributes this interference to a processing limitation at the motor level. By contrast, the response monitoring hypothesis attributes it to a bottleneck process that…

A Test of Motor (Not Executive) Planning in Developmental Coordination Disorder and Autism

ERIC Educational Resources Information Center

van Swieten, Lisa M.; van Bergen, Elsje; Williams, Justin H. G.; Wilson, Andrew D.; Plumb, Mandy S.; Kent, Samuel W.; Mon-Williams, Mark A.

2010-01-01

Grip selection tasks have been used to test "planning" in both autism and developmental coordination disorder (DCD). We differentiate between "motor" and "executive" planning and present a modified motor planning task. Participants grasped a cylinder in 1 of 2 orientations before turning it clockwise or anticlockwise.…

Executive Functions: Formative versus Reflective Measurement

ERIC Educational Resources Information Center

Willoughby, Michael; Holochwost, Steven J.; Blanton, Zane E.; Blair, Clancy B.

2014-01-01

The primary objective of this article was to critically evaluate the routine use of confirmatory factor analysis (CFA) for representing an individual's performance across a battery of executive function tasks. A conceptual review and statistical reanalysis of N = 10 studies that used CFA methods of EF tasks was undertaken. Despite evidence of…

Wandering Minds and Wavering Rhythms: Linking Mind Wandering and Behavioral Variability

ERIC Educational Resources Information Center

Seli, Paul; Cheyne, James Allan; Smilek, Daniel

2013-01-01

Mind wandering is a pervasive feature of human cognition often associated with the withdrawal of task-related executive control processes. Here, we explore the possibility that, in tasks requiring executive control to sustain consistent responding, moments of mind wandering could be associated with moments of increased behavioral variability. To…

Toddlers Benefit from Labeling on an Executive Function Search Task

ERIC Educational Resources Information Center

Miller, Stephanie E.; Marcovitch, Stuart

2011-01-01

Although labeling improves executive function (EF) performance in children older than 3 years, the results from studies with younger children have been equivocal. In the current study, we assessed performance in a computerized multistep multilocation search task with older 2-year-olds. The correct search location was either (a) not marked by a…

Computer architecture for efficient algorithmic executions in real-time systems: New technology for avionics systems and advanced space vehicles

NASA Technical Reports Server (NTRS)

Carroll, Chester C.; Youngblood, John N.; Saha, Aindam

1987-01-01

Improvements and advances in the development of computer architecture now provide innovative technology for the recasting of traditional sequential solutions into high-performance, low-cost, parallel system to increase system performance. Research conducted in development of specialized computer architecture for the algorithmic execution of an avionics system, guidance and control problem in real time is described. A comprehensive treatment of both the hardware and software structures of a customized computer which performs real-time computation of guidance commands with updated estimates of target motion and time-to-go is presented. An optimal, real-time allocation algorithm was developed which maps the algorithmic tasks onto the processing elements. This allocation is based on the critical path analysis. The final stage is the design and development of the hardware structures suitable for the efficient execution of the allocated task graph. The processing element is designed for rapid execution of the allocated tasks. Fault tolerance is a key feature of the overall architecture. Parallel numerical integration techniques, tasks definitions, and allocation algorithms are discussed. The parallel implementation is analytically verified and the experimental results are presented. The design of the data-driven computer architecture, customized for the execution of the particular algorithm, is discussed.

Computer architecture for efficient algorithmic executions in real-time systems: new technology for avionics systems and advanced space vehicles

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

Carroll, C.C.; Youngblood, J.N.; Saha, A.

1987-12-01

Improvements and advances in the development of computer architecture now provide innovative technology for the recasting of traditional sequential solutions into high-performance, low-cost, parallel system to increase system performance. Research conducted in development of specialized computer architecture for the algorithmic execution of an avionics system, guidance and control problem in real time is described. A comprehensive treatment of both the hardware and software structures of a customized computer which performs real-time computation of guidance commands with updated estimates of target motion and time-to-go is presented. An optimal, real-time allocation algorithm was developed which maps the algorithmic tasks onto the processingmore » elements. This allocation is based on the critical path analysis. The final stage is the design and development of the hardware structures suitable for the efficient execution of the allocated task graph. The processing element is designed for rapid execution of the allocated tasks. Fault tolerance is a key feature of the overall architecture. Parallel numerical integration techniques, tasks definitions, and allocation algorithms are discussed. The parallel implementation is analytically verified and the experimental results are presented. The design of the data-driven computer architecture, customized for the execution of the particular algorithm, is discussed.« less

Prospective memory in preschool children: influences of agency, incentive, and underlying cognitive mechanisms.

PubMed

Causey, Kayla B; Bjorklund, David F

2014-11-01

Prospective memory (PM) is remembering to perform an action in the future and is crucial to achieving goal-directed activities in everyday life. Doing so requires that an intention is encoded, retained during a delay interval, and retrieved at the appropriate time of execution. We examined PM ability in preschool children by manipulating factors related to agency and incentive. We further explored how metacognition, executive functioning, and theory of mind-factors known to account for individual differences in PM-influenced performance on these PM tasks. A sample of 31 preschool children were asked to carry out a delayed intention or to remind an adult to carry out an intention that was of high or low incentive to the children. Findings indicated that individual differences in theory of mind were related to individual differences in preschoolers' performance on low-incentive PM tasks, independent of executive functioning contributions, whereas individual differences in executive functioning were related to performance on the high-incentive tasks. These findings suggest that changes in theory of mind and executive functioning are important to consider in models of PM and that different PM tasks (e.g., high vs. low incentive) may involve different cognitive requirements for young children. Copyright © 2014 Elsevier Inc. All rights reserved.

Radiation-Hardened Circuitry Using Mask-Programmable Analog Arrays. Report 3

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

Britton, Jr, Charles L.; Shelton, Jacob H.; Ericson, Milton Nance

As the recent accident at Fukushima Daiichi so vividly demonstrated, telerobotic technologies capable of withstanding high radiation environments need to be readily available to enable operations, repair, and recovery under severe accident scenarios when human entry is extremely dangerous or not possible. Telerobotic technologies that enable remote operation in high dose rate environments have undergone revolutionary improvement over the past few decades. However, much of this technology cannot be employed in nuclear power environments because of the radiation sensitivity of the electronics and the organic insulator materials currently in use. This is a report of the activities involving Task 3more » of the Nuclear Energy Enabling Technologies (NEET) 2 project Radiation Hardened Circuitry Using Mask-Programmable Analog Arrays [1]. Evaluation of the performance of the system for both pre- and post-irradiation as well as operation at elevated temperature will be performed. Detailed performance of the system will be documented to ensure the design meets requirements prior to any extended evaluation. A suite of tests will be developed which will allow evaluation before and after irradiation and during temperature. Selection of the radiation exposure facilities will be determined in the early phase of the project. Radiation exposure will consist of total integrated dose (TID) up to 200 kRad or above with several intermediate doses during test. Dose rates will be in various ranges determined by the facility that will be used with a target of 30 kRad/hr. Many samples of the pre-commercial devices to be used will have been tested in previous projects to doses of at least 300 kRad and temperatures up to 125C. The complete systems will therefore be tested for performance at intermediate doses. Extended temperature testing will be performed up to the limit of the commercial sensors. The test suite performed at each test point will consist of operational testing of the three basic measurement functions plus electronic functional testing (power dissipation, voltage offset changes, noise variations, etc.). This suite will be developed as part of this task.« less

[Decision making and executive function in severe traumatic brain injured patients: validation of a decision-making task and correlated features].

PubMed

Wiederkehr, S; Barat, M; Dehail, P; de Sèze, M; Lozes-Boudillon, S; Giroire, J-M

2005-02-01

At the chronic stage, severe traumatic brain injured (TBI) patients experience difficulty in making decisions. Several studies have demonstrated the involvement of the prefrontal cortex, in particular the orbitofrontal region, in decision-making. The aim of the present study was to validate a decision-making task in this population and to ascertain whether the components of their dysexecutive syndrome may affect their decision-making and lead to difficulties for social rehabilitation. Fifteen TBI patients and 15 controlled subjects matched for age, sex and years of education were assessed by a battery of executive tests (GREFEX) and by the gambling task (GT). The TBI subjects performed significantly worse than the controlled group in five out of six GREFEX tests. The TBI choices are significantly more disadvantageous than the choices of the control group when considering the three last blocks of 20 cards of the GT. The GT total score correlated significantly with execution time of the Stroop interference condition and the Trail Making Task B, as well as with the two measures (correct sequence span and number of crossed boxes) of the double condition of Baddeley's task. We postulate that executive functioning (supervisory attentional system) influence performance in the gambling task through mechanisms of inhibitory control, divided attention and working memory. Thus, this task seems to be determined by multiple factors; the process of decision-making may depend on frontal integrity.

The differential effects of ecstasy/polydrug use on executive components: shifting, inhibition, updating and access to semantic memory.

PubMed

Montgomery, Catharine; Fisk, John E; Newcombe, Russell; Murphy, Phillip N

2005-10-01

Recent theoretical models suggest that the central executive may not be a unified structure. The present study explored the nature of central executive deficits in ecstasy users. In study 1, 27 ecstasy users and 34 non-users were assessed using tasks to tap memory updating (computation span; letter updating) and access to long-term memory (a semantic fluency test and the Chicago Word Fluency Test). In study 2, 51 ecstasy users and 42 non-users completed tasks that assess mental set switching (number/letter and plus/minus) and inhibition (random letter generation). MANOVA revealed that ecstasy users performed worse on both tasks used to assess memory updating and on tasks to assess access to long-term memory (C- and S-letter fluency). However, notwithstanding the significant ecstasy group-related effects, indices of cocaine and cannabis use were also significantly correlated with most of the executive measures. Unexpectedly, in study 2, ecstasy users performed significantly better on the inhibition task, producing more letters than non-users. No group differences were observed on the switching tasks. Correlations between indices of ecstasy use and number of letters produced were significant. The present study provides further support for ecstasy/polydrug-related deficits in memory updating and in access to long-term memory. The surplus evident on the inhibition task should be treated with some caution, as this was limited to a single measure and has not been supported by our previous work.

Control Software for a High-Performance Telerobot

NASA Technical Reports Server (NTRS)

Kline-Schoder, Robert J.; Finger, William

2005-01-01

A computer program for controlling a high-performance, force-reflecting telerobot has been developed. The goal in designing a telerobot-control system is to make the velocity of the slave match the master velocity, and the environmental force on the master match the force on the slave. Instability can arise from even small delays in propagation of signals between master and slave units. The present software, based on an impedance-shaping algorithm, ensures stability even in the presence of long delays. It implements a real-time algorithm that processes position and force measurements from the master and slave and represents the master/slave communication link as a transmission line. The algorithm also uses the history of the control force and the slave motion to estimate the impedance of the environment. The estimate of the impedance of the environment is used to shape the controlled slave impedance to match the transmission-line impedance. The estimate of the environmental impedance is used to match the master and transmission-line impedances and to estimate the slave/environment force in order to present that force immediately to the operator via the master unit.

Executive functions in becoming writing readers and reading writers: note taking and report writing in third and fifth graders.

PubMed

Altemeier, Leah; Jones, Janine; Abbott, Robert D; Berninger, Virginia W

2006-01-01

Results are reported for a study of 2 separate processes of report writing-taking notes while reading source material and composing a report from those notes-and related individual differences in executive functions involved in integrating reading and writing during these writing activities. Third graders (n = 122) and 5th graders (n = 106; overall, 127 girls and 114 boys) completed two reading-writing tasks-read paragraph (mock science text)-write notes and use notes to generate written report, a reading comprehension test, a written expression test, four tests of executive functions (inhibition, verbal fluency, planning, switching attention), and a working memory test. For the read-take notes task, the same combination of variables was best (explained the most variance and each variable added unique variance) for 3rd graders and 5th graders: Wechsler Individual Achievement Test-Second Edition (WIAT-II) Reading Comprehension, Process Assessment of the Learner Test for Reading and Writing (PAL) Copy Task B, WIAT-II Written Expression, and Delis-Kaplan Executive Function System (D-KEFS) Inhibition. For the use notes to write report task, the best combinations of variables depended on grade level: For 3rd graders, WIAT-II Reading Comprehension, WIAT-II Written Expression, D-KEFS Verbal Fluency, and Tower of Hanoi; for 5th graders, WIAT-II Reading Comprehension, D-KEFS Verbal Fluency, WIAT-II Written Expression, and PAL Alphabet Task. These results add to prior research findings that executive functions contribute to the writing development of elementary-grade students and additionally support the hypothesis that executive functions play a role in developing reading-writing connections.

Implicit and explicit false belief development in preschool children.

PubMed

Grosse Wiesmann, Charlotte; Friederici, Angela D; Singer, Tania; Steinbeis, Nikolaus

2017-09-01

The ability to represent the mental states of other agents is referred to as Theory of Mind (ToM). A developmental breakthrough in ToM consists of understanding that others can have false beliefs about the world. Recently, infants younger than 2 years of age have been shown to pass novel implicit false belief tasks. However, the processes underlying these tasks and their relation to later-developing explicit false belief understanding, as well as to other cognitive abilities, are not yet understood. Here, we study a battery of implicit and explicit false belief tasks in 3- and 4-year-old children, relating their performance to linguistic abilities and executive functions. The present data show a significant developmental change from failing explicit false belief tasks at 3 years of age to passing them at the age of 4, while both age groups pass implicit false belief tasks. This differential developmental trajectory is reflected by the finding that explicit and implicit false belief tasks do not correlate. Further, we demonstrate that explicit false belief tasks correlate with syntactic and executive functions, whereas implicit false belief tasks do not. The study thus indicates that the processes underlying implicit false belief tasks are different from later-developing explicit false belief understanding. Moreover, our results speak for a critical role of syntactic and executive functions for passing standard explicit false belief tasks in contrast to implicit tasks. © 2016 John Wiley & Sons Ltd.