Effects of tactile cueing on concurrent performance of military and robotics tasks in a simulated multitasking environment

This study examined the concurrent performance of military gunnery, robotics control and communication tasks in a simulated environment. More specifically, the study investigated how aided target recognition (AiTR) capabilities (delivered either through tactile or tactile + visual cueing) for the gunnery task might benefit overall performance. Results showed that AiTR benefited not only the gunnery task, but also the concurrent robotics and communication tasks. The participants' spatial ability was found to be a good indicator of their gunnery and robotics task performance. However, when AiTR was available to assist their gunnery task, those participants of lower spatial ability were able to perform their robotics tasks as well as those of higher spatial ability. Finally, participants' workload assessment was significantly higher when they teleoperated (i.e. remotely operated) a robot and when their gunnery task was unassisted. These results will further understanding of multitasking performance in military tasking environments. These results will also facilitate the implementation of robots in military settings and will provide useful data to military system designs.     

Effects of display design on performance in a simulated ship navigation environment

Although automation is playing an increasing role on the ship's bridge, empirical research on the effectiveness of alternative bridge designs is limited. In this paper, we describe an experimental study of the benefits of integrated information display, using a computerized simulation of a highly automated ship's bridge. The study compared three types of interface design, which presented radar and electronic chart information to the operator in different ways: (a) integrated display, (b) functionally-separate display, and (c) spatially-separate display. Effects were examined in relation to time on watch and scenario complexity. Following extensive training on the task, 39 participants were tested over a 4-h experimental session, during which they encountered a sequence of collision scenarios of varying complexity. Using a dual-task methodology, a range of measures of primary and secondary task performance were taken, together with assessment of information sampling behaviour and subjective operator state (workload, fatigue, anxiety and situation awareness). The results indicated slight navigational advantages of the integrated display over the two alternative display types, although it also incurred higher levels of operator cost, particularly fatigue. There were no marked effects of time on watch, but more complex scenarios were associated with impaired performance, increased workload and reduced situation awareness. Overall, the findings have suggested some benefits of integrating primary information sources in a ship's bridge environment. The study further confirms the value of experimental simulations as tools for investigating design issues for ship's bridge automation.     

Effects of display design on performance in a simulated ship navigation environment

Although automation is playing an increasing role on the ship's bridge, empirical research on the effectiveness of alternative bridge designs is limited. In this paper, we describe an experimental study of the benefits of integrated information display, using a computerized simulation of a highly automated ship's bridge. The study compared three types of interface design, which presented radar and electronic chart information to the operator in different ways: (a) integrated display, (b) functionally-separate display, and (c) spatially-separate display. Effects were examined in relation to time on watch and scenario complexity. Following extensive training on the task, 39 participants were tested over a 4-h experimental session, during which they encountered a sequence of collision scenarios of varying complexity. Using a dual-task methodology, a range of measures of primary and secondary task performance were taken, together with assessment of information sampling behaviour and subjective operator state (workload, fatigue, anxiety and situation awareness). The results indicated slight navigational advantages of the integrated display over the two alternative display types, although it also incurred higher levels of operator cost, particularly fatigue. There were no marked effects of time on watch, but more complex scenarios were associated with impaired performance, increased workload and reduced situation awareness. Overall, the findings have suggested some benefits of integrating primary information sources in a ship's bridge environment. The study further confirms the value of experimental simulations as tools for investigating design issues for ship's bridge automation.     

The effects of grouping and cueing in the performance of location tasks

In location tasks such as assembly of a control panel, operators respond to stimulus information by locating a given target in an extensive set of response alternatives. Arrangement of the response alternatives and the method of presenting the location information (cueing), as well as the interaction between these factors, were hypothesised to influence performance in this type of task. To test these hypotheses, a factorial experiment involving 60 subjects was performed in which five levels of grouping and four levels of cueing were investigated. Grouping appeared to affect location accuracy more than location time, whereas the effects of cueing were found to be significant for both location accuracy and time. The absence of an interaction effect between grouping and cueing suggested that the effects of these factors on performance were independent.     

Computational tasks in robotics and factory automation

The design of Manufacturing Planning and Control Systems (MPCSs) — systems that negotiate with Customers and Suppliers to exchange products in return for money in order to generate profit, is discussed.The computational task of MPCS components are systematically specified as a starting point for the development of computational engines, as computer systems and programs, that execute the specified computation. Key issues are the overwhelming complexity and frequently changing application of MPCSs.     

Evolutionary research of optimal strategies for exclusive positioned clustering in simulated environment of collective robotics

One of the captivating characteristics of social insects, in spite of their rudimentary individual constitution, is the ability by which they have to solve complicated problems in an elastic and robust way. This includes elasticity which ensures the adaptation of the insect system to the unpredictable changes of their environment, and robustness which guarantees a functioning continuity of the system, in spite of the possible failure of a certain number of its elements in the achievement of their individual missions. From this point of view, fields of research have emerged over the past decades, with the aim of trying to reveal the secret behind the relationship between individual and society, so perfectly designed in nature. Collective robotics is one of those fields where we try to find microscopic rules allowing a group of autonomous robots, mobile and with limited capacity, to carry out a specific macro-task, such as exclusive positioned heap formation. The idea, behind this, is to use a model of oriented reactive agent simulation, to seek the relations which can link the local perceptions of the simulated robots with their basic actions, in order to make the above mentioned gathering task a success. An evolutionary approach is used for this purpose, making it possible to discover the functional control relations of these simulated robots. An analogy with the precepts specific to the ant community is established and results of simulation indicating the effectiveness of the detected rules are presented.     

The effects of heuristic rule training on operator performance in a simulated process control environment

In complex work environments, the occurrence of novel system states represents a particular challenge for the design of training. This article is concerned with the use of heuristic rules to prepare operators for the management of unfamiliar fault states. An experiment was carried out to examine the effects of heuristic rule training on operator performance and system management behaviour. Thirty-nine trainee operators from the chemical industry took part in the study. They were trained for 4 h on a PC-based simulation of a process control task. Operators in the experimental group received training on heuristic rules while operators in the control group did not. One week later the operators participated in a 70-min testing session. While the results showed that heuristic rules training led to better diagnostic performance, it was also associated with increased operator fatigue and impaired secondary task performance. The implications of the findings for using heuristic rule training are discussed.     

The effects of heuristic rule training on operator performance in a simulated process control environment

In complex work environments, the occurrence of novel system states represents a particular challenge for the design of training. This article is concerned with the use of heuristic rules to prepare operators for the management of unfamiliar fault states. An experiment was carried out to examine the effects of heuristic rule training on operator performance and system management behaviour. Thirty-nine trainee operators from the chemical industry took part in the study. They were trained for 4 h on a PC-based simulation of a process control task. Operators in the experimental group received training on heuristic rules while operators in the control group did not. One week later the operators participated in a 70-min testing session. While the results showed that heuristic rules training led to better diagnostic performance, it was also associated with increased operator fatigue and impaired secondary task performance. The implications of the findings for using heuristic rule training are discussed.     

Framework of a multitasking C++ based programming environment MCPE

Development of integrated programming environments has faced two problems: response degression, with an incresing execution delay when more tools have been included in an environment, and poor extensibility, with difficulties in adding new tools to an environment. Framework of a multitasking C++ based programming environment MCPE has been presented here for solving these problems. MCPE contains several concurrent tasks (processes): one of them is interacting with the user and the others are simultaneously doing their jobs. Process scheduling and concurrency control in MCPE have been carefully designed: response time is then reduced, and unnecessary computations are avoided. An event-driven serving model providing flexible task communications eases the addition of tools. Shared data stores have been defined as monitor types with no nested monitor calls in preventing deadlock. Consistency among the tasks has also been assured. A prototype has also been presented to show feasibility.     

Effects of moderate cold on performance of psychomotor and cognitive tasks

Two experiments were performed to study the effects of exposure to moderate cold ( + 5°C) on psychomotor and cognitive tasks requiring sustained attention. Twelve male and 12 female subjects participated. Skin and core temperatures, heart rate and subjective ratings were recorded. Considerable decrements in manual dexterity were found during exposure, but no effects on simple reaction time or speed of correct response were observed. The effects of cold on the performance of complex tasks were demonstrated as an increase in the number of errors and the speed of incorrect response and as an increase in the number of false alarms on two computerized performance tests. The results, indicating a negative effect of moderate cold exposure on tasks which require speed and which encourage erroneous responses, are discussed in terms of theories of arousal and distraction.     

Timing of cueing in complex problem-solving tasks: Learner versus system control

Task-specific cueing formats that promote the automation and construction of problem-solving schemas should ideally be presented just in time to students learning to solve complex problems. This article reports experimental work comparing learner-controlled cueing, system-controlled cueing, and no cueing among 34 sophomore law students in a multimedia practical aimed at learning to prepare and hold a plea in court. The cueing consisted of a combination of process worksheets (PW) and worked out examples (WOE). Our main hypotheses that participants with cueing would outperform those without cueing and that participants with learner-controlled cueing would outperform those with system-controlled cueing were partly confirmed by the learning and transfer outcomes on a training and transfer task. Theoretical and practical implications of these findings are discussed.     

Coordinated execution of tasks in a multiagent environment

This correspondence describes the application of discrete event control methods to provide conflict-free plan execution in a multiagent environment. This work uses planning methods to generate plans for multiple robots, and the plans are then compiled into Petri nets for analysis, execution, and monitoring. Supervisory control techniques are applied to the Petri net controller for the purpose of dealing with conflicts that arise due to the presence of shared resources. Furthermore, by preserving the state of the system replanning can occur at any time during execution to deal with unforeseen events.     

Improving scheduling of tasks in a heterogeneous environment

Optimal scheduling of parallel tasks with some precedence relationship, onto a parallel machine is known to be NP-complete. The complexity of the problem increases when task scheduling is to be done in a heterogeneous environment, where the processors in the network may not be identical and take different amounts of time to execute the same task. We introduce a task duplication-based scheduling algorithm for network of heterogeneous systems (TANH), with complexity O(V/sup 2/), which provides optimal results for applications represented by directed acyclic graphs (DAGs), provided a simple set of conditions on task computation and network communication time could be satisfied. The performance of the algorithm is illustrated by comparing the scheduling time with an existing "best imaginary level scheduling (BIL)" scheme for heterogeneous systems. The scalability for a higher or lower number of processors, as per their availability is also discussed. We have shown to provide substantial improvement over existing work on the task duplication-based scheduling algorithm (TDS).     

Effects of respirators on performance of physical, psychomotor and cognitive tasks

Possible work decrements caused by respirator usage were examined. A battery of physical, psychomotor and cognitive tasks was used to investigate the effects of respirator wear on 12 subjects. A repeated measures experimental design was used to study the effects of three types of respirators: a disposable dust mask; an air purifying half-mask; and a full-face airline mask. Performance while wearing a mask was compared to the control condition without a respirator. The results from the physical work task of riding a bicycle ergometer indicated approximately a 10% increase in oxygen consumption when subjects wore half and full-face masks in comparison to when they performed the tasks without a mask. The results indicate that wearing the respirators did not have a significant effect on the performance of cognitive tasks but did affect significantly the performance of psychomotor tasks such as steadiness of work performance and movements requiring accurate control for positioning of objects.     

The effects of military body armour on trunk and hip kinematics during performance of manual handling tasks*

Musculoskeletal injuries are reported as burdening the military. An identified risk factor for injury is carrying heavy loads; however, soldiers are also required to wear their load as body armour. To investigate the effects of body armour on trunk and hip kinematics during military-specific manual handling tasks, 16 males completed 3 tasks while wearing each of 4 body armour conditions plus a control. Three-dimensional motion analysis captured and quantified all kinematic data. Average trunk flexion for the weightiest armour type was higher compared with control during the carry component of the ammunition box lift (p?<?0.001) and sandbag lift tasks (p?<?0.001). Trunk rotation ROM was lower for all armour types compared with control during the ammunition box place component (p?<?0.001). The altered kinematics with body armour occurred independent of armour design. In order to optimise armour design, manufacturers need to work with end-users to explore how armour configurations interact with range of personal and situational factors in operationally relevant environments.

Practitioner Summary: Musculoskeletal injuries are reported as burdening the military and may relate to body armour wear. Body armour increased trunk flexion and reduced trunk rotation during military-specific lifting and carrying tasks. The altered kinematics may contribute to injury risk, but more research is required.     

Improving performance and determinism of multitasking systems on the LEON architecture

Real-time systems are characterised by the fact that they have to meet a set of both functional and temporal requirements. Processor architectures have a significant impact on the predictability of software execution times and can add different sources of indeterminism depending on the features provided. The LEON processor family is the reference platform for space missions of the European Space Agency, with open-source implementations that are written in VHDL language. All versions of the LEON processors conform to the SPARC architecture Version 8. This architecture groups the general-purpose registers into windows to reduce memory transfer overhead in function calls. Unfortunately, this mechanism introduces indeterminism in software execution times at various levels. In this paper, we propose an extension to the original architecture that provides determinism for a configurable subset of tasks and interrupt service routines and eliminates the concurrency-related jitter, all this with a minimum cost in terms of FPGA resource utilisation. For the validation of the proposed solution, we have implemented the extension into the VHDL code of the LEON3 processor and modified the source code of the RTEMS operating system to make use of the new functionality.