A study of aspects of synchronisation and communication in certain parallel computer architectures

This paper examines methods for synchronisation and communication between tasks in highly parallel arrays of processors. The development of various methods is researched and simulation techniques are applied to specific structures, to examine their effectiveness. Two approaches to simulation are presented, in the first case a discrete event simulator is applied to task synchronisation implemented with semaphores in a close coupled environment. Secondly the concurrent programming language Occam is used to simulate a systolic configuration of processors. In this case the design is verified, through actual system construction. Conclusions are drawn regarding the design disciplines and structure imposed by the use of these simulation techniques. A close relationship is found between the behaviour of a simulation written in Occam and the same structure constructed from multiple processors. Further research is suggested into the subject of dataflow processors, to find suitable means for simulating such systems, prior to implementation. A type of test vehicle is proposed that would operate a dataflow processor under the control of the development system

Brain computer interface based robotic rehabilitation with online modification of task speed

We present a systematic approach that enables online modification/adaptation of robot assisted rehabilitation exercises by continuously monitoring intention levels of patients utilizing an electroencephalogram (EEG) based Brain-Computer Interface (BCI). In particular, we use Linear Discriminant Analysis (LDA) to classify event-related synchronization (ERS) and desynchronization (ERD) patterns associated with motor imagery; however, instead of providing a binary classification output, we utilize posterior probabilities extracted from LDA classifier as the continuous-valued outputs to control a rehabilitation robot. Passive velocity field control (PVFC) is used as the underlying robot controller to map instantaneous levels of motor imagery during the movement to the speed of contour following tasks. In other words, PVFC changes the speed of contour following tasks with respect to intention levels of motor imagery. PVFC also allows decoupling of the task and the speed of the task from each other, and ensures coupled stability of the overall robot patient system. The proposed framework is implemented on AssistOn-Mobile - a series elastic actuator based on a holonomic mobile platform, and feasibility studies with healthy volunteers have been conducted test effectiveness of the proposed approach. Giving patients online control over the speed of the task, the proposed approach ensures active involvement of patients throughout exercise routines and has the potential to increase the efficacy of robot assisted therapies

Advanced manned space flight simulation and training: An investigation of simulation host computer system concepts

The findings of a preliminary investigation by Southwest Research Institute (SwRI) in simulation host computer concepts is presented. It is designed to aid NASA in evaluating simulation technologies for use in spaceflight training. The focus of the investigation is on the next generation of space simulation systems that will be utilized in training personnel for Space Station Freedom operations. SwRI concludes that NASA should pursue a distributed simulation host computer system architecture for the Space Station Training Facility (SSTF) rather than a centralized mainframe based arrangement. A distributed system offers many advantages and is seen by SwRI as the only architecture that will allow NASA to achieve established functional goals and operational objectives over the life of the Space Station Freedom program. Several distributed, parallel computing systems are available today that offer real-time capabilities for time critical, man-in-the-loop simulation. These systems are flexible in terms of connectivity and configurability, and are easily scaled to meet increasing demands for more computing power

Sixth Annual Users' Conference

Conference papers and presentation outlines which address the use of the Transportable Applications Executive (TAE) and its various applications programs are compiled. Emphasis is given to the design of the user interface and image processing workstation in general. Alternate ports of TAE and TAE subsystems are also covered

Parallel process placement

This thesis investigates methods of automatic allocation of processes to available processors in a given network configuration. The research described covers the investigation of various algorithms for optimal process allocation. Among those researched were an algorithm which used a branch and bound technique, an algorithm based on graph theory, and an heuristic algorithm involving cluster analysis. These have been implemented and tested in conjunction with the gathering of performance statistics during program execution, for use in improving subsequent allocations. The system has been implemented on a network of loosely-coupled microcomputers using multi-port serial communication links to simulate a transputer network. The concurrent programming language occam has been implemented, replacing the explicit process allocation constructs with an automatic placement algorithm. This enables the source code to be completely separated from hardware consideration

Rethinking the "mirroring" hypothesis: implications for technological modularity, tacit coordination, and radical innovation

Studies of the 'mirroring' hypothesis have demonstrated the relationships between technological modularity and explicit coordination, yet little is known about the 'mirroring' relationship between technological modularity and tacit coordination, and how the 'mirroring' relationship may affect radical innovation. This paper contributes to the 'mirroring' hypothesis by identifying the interaction mechanisms embedded in and surrounded over the mirroring relationships. Using survey data of 121 high-tech firms in China, our study indicates that technological modularity enhances interfirm tacit coordination between module-makers ('mirroring' hypothesis), and will also positively influence radical innovation ('outcome' hypothesis). Moreover, tacit coordination negatively moderates the impact of technological modularity on radical innovation ('interaction' hypothesis), indicating that the 'mirroring' relationship may offset the benefit obtained from modularization. It also suggests that, in a high-technology industry in underdeveloped areas, tacit coordination could lead to exposure of hidden knowledge, thus lowering module-makers' motivation for technology breakthrough

Design of a monitor for the debugging and development of multiprocessing process control systems : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Computing Technology at Massey University

This thesis describes the design of a general purpose tool for debugging and developing multimicroprocessor process control systems. With the decreasing pnce of computers, multimicroprocessors are increasingly being used for process control. However, the lack of published information on multiprocessing systems and distributed systems has meant that methodologies and tools for debugging and developing such systems have been slow to develop. The monitor designed here is system independent, a considerable advantage over other such tools that are currently available

Aerospace Applications of Microprocessors

An assessment of the state of microprocessor applications is presented. Current and future requirements and associated technological advances which allow effective exploitation in aerospace applications are discussed