Fault-free validation of a fault-tolerant multiprocessor: Baseline experiments and workoad implementation

In the future, aircraft employing active control technology must use highly reliable multiprocessors in order to achieve flight safety. Such computers must be experimentally validated before they are deployed. This project outlines a methodology for doing fault-free validation of reliable multiprocessors. The methodology begins with baseline experiments, which test single phenomenon. As experiments progress, tools for performance testing are developed. This report presents the results of interrupt baseline experiments performed on the Fault-Tolerant Multiprocessor (FTMP) at NASA-Langley's AIRLAB. Interrupt-causing excepting conditions were tested, and several were found to have unimplemented interrupt handling software while one had an unimplemented interrupt vector. A synthetic workload model for realtime multiprocessors is then developed as an application level performance analysis tool. Details of the workload implementation and calibration are presented. Both the experimental methodology and the synthetic workload model are general enough to be applicable to reliable multi-processors besides FTMP

FTMP (Fault Tolerant Multiprocessor) programmer's manual

The Fault Tolerant Multiprocessor (FTMP) computer system was constructed using the Rockwell/Collins CAPS-6 processor. It is installed in the Avionics Integration Research Laboratory (AIRLAB) of NASA Langley Research Center. It is hosted by AIRLAB's System 10, a VAX 11/750, for the loading of programs and experimentation. The FTMP support software includes a cross compiler for a high level language called Automated Engineering Design (AED) System, an assembler for the CAPS-6 processor assembly language, and a linker. Access to this support software is through an automated remote access facility on the VAX which relieves the user of the burden of learning how to use the IBM 4381. This manual is a compilation of information about the FTMP support environment. It explains the FTMP software and support environment along many of the finer points of running programs on FTMP. This will be helpful to the researcher trying to run an experiment on FTMP and even to the person probing FTMP with fault injections. Much of the information in this manual can be found in other sources; we are only attempting to bring together the basic points in a single source. If the reader should need points clarified, there is a list of support documentation in the back of this manual

An Investigation into Cognitive Radio System Performance

The objective of this thesis is to explore cognitive radio performance through an in-depth literature review and an implementation of a software-defined radio prototyping system. Specifically, this thesis investigates the spectrum-sensing aspect of cognitive radio by comparing two spectrum-sensing methods. It was found in the literature review that a system utilizing matched filter detection would provide higher probability of detection in low signal-to-noise ratio environments when compared to a system utilizing energy detection. These spectrum sensing methods were thus implemented and compared in the cognitive radio systems presented in this thesis. Additionally, experiments were conducted to determine the most efficient intervals for the spectrum sensing and cycle interval periods. Therefore, system performance was measured on the basis of probability of successful primary user signal detection and maximum throughput capabilities, quantified by bit error rate. It was found that a cognitive radio system based on matched filter detection was more robust, given that the transmitted signal of interest was previously known. However, compared to a system based on energy detection, the implementation of the matched filter required more complex algorithms and computational power. These results are consistent with the findings in the literature review

The Evolution of Successful Service-Learning Courses in the Computing Curriculum: From Infancy to innovation

The purpose of this paper is to relate the evolution of successful service-learning courses in a school of computer science and information systems spanning over a 20-year period. The authors share their experiences in developing technology-based service-learning courses for both majors and non-majors. Most recently, these courses have enabled undergraduate first-year students to be exposed to exciting technologies, such as robotics and mobile app development. The challenges, benefits, and lessons learned are discussed

Organisational culture of further education colleges delivering higher education business programmes: developing a culture of ‘HEness’ – what next?

This paper draws on the views of lecturers working in and delivering college-based higher education (CBHE) in the UK. There have been numerous works on the culture of higher education in further education (HE in FE). However, as noted by some literati, the culture of further education (FE) is not easy to define, and does not readily lend itself to the incorporation of a higher education (HE) culture. This could be due to the large number of changes FE has had to adopt owing to various government policies. The study comprises 26 in-depth individual interviews conducted at various further education colleges throughout the Yorkshire and Humber region of the UK. Via the use of an interpretivist approach, common themes and word use were extracted from the narratives for analysis. The organisational culture of these further education colleges was relatively easy to define, the word ‘blame’ being one of the common themes. However, when identifying if the individual colleges had a HE culture; this proved more difficult

Search based software engineering: Trends, techniques and applications

© ACM, 2012. This is the author's version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version is available from the link below.In the past five years there has been a dramatic increase in work on Search-Based Software Engineering (SBSE), an approach to Software Engineering (SE) in which Search-Based Optimization (SBO) algorithms are used to address problems in SE. SBSE has been applied to problems throughout the SE lifecycle, from requirements and project planning to maintenance and reengineering. The approach is attractive because it offers a suite of adaptive automated and semiautomated solutions in situations typified by large complex problem spaces with multiple competing and conflicting objectives. This article provides a review and classification of literature on SBSE. The work identifies research trends and relationships between the techniques applied and the applications to which they have been applied and highlights gaps in the literature and avenues for further research.EPSRC and E

A note on a matrix criterion for unique colorability of a signed graph

A signed graph, S , is colorable if its point set can be partitioned into subsets such that all positive lines join points of the same subset and all negative lines join points of different subsets. S is uniquely colorable if there is only one such partition. Developed in this note is a new matrix, called the type matrix of S , which provides a classification of the way pairs of points are joined in S . Such a classification yields a criterion for colorability and unique colorability.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45725/1/11336_2005_Article_BF02289592.pd