Optimizing for a Many-Core Architecture without Compromising Ease-of-Programming

Faced with nearly stagnant clock speed advances, chip manufacturers have turned to parallelism as the source for continuing performance improvements. But even though numerous parallel architectures have already been brought to market, a universally accepted methodology for programming them for general purpose applications has yet to emerge. Existing solutions tend to be hardware-specific, rendering them difficult to use for the majority of application programmers and domain experts, and not providing scalability guarantees for future generations of the hardware. This dissertation advances the validation of the following thesis: it is possible to develop efficient general-purpose programs for a many-core platform using a model recognized for its simplicity. To prove this thesis, we refer to the eXplicit Multi-Threading (XMT) architecture designed and built at the University of Maryland. XMT is an attempt at re-inventing parallel computing with a solid theoretical foundation and an aggressive scalable design. Algorithmically, XMT is inspired by the PRAM (Parallel Random Access Machine) model and the architecture design is focused on reducing inter-task communication and synchronization overheads and providing an easy-to-program parallel model. This thesis builds upon the existing XMT infrastructure to improve support for efficient execution with a focus on ease-of-programming. Our contributions aim at reducing the programmer's effort in developing XMT applications and improving the overall performance. More concretely, we: (1) present a work-flow guiding programmers to produce efficient parallel solutions starting from a high-level problem; (2) introduce an analytical performance model for XMT programs and provide a methodology to project running time from an implementation; (3) propose and evaluate RAP -- an improved resource-aware compiler loop prefetching algorithm targeted at fine-grained many-core architectures; we demonstrate performance improvements of up to 34.79% on average over the GCC loop prefetching implementation and up to 24.61% on average over a simple hardware prefetching scheme; and (4) implement a number of parallel benchmarks and evaluate the overall performance of XMT relative to existing serial and parallel solutions, showing speedups of up to 13.89x vs.~ a serial processor and 8.10x vs.~parallel code optimized for an existing many-core (GPU). We also discuss the implementation and optimization of the Max-Flow algorithm on XMT, a problem which is among the more advanced in terms of complexity, benchmarking and research interest in the parallel algorithms community. We demonstrate better speed-ups compared to a best serial solution than previous attempts on other parallel platforms

RFID Technology in Intelligent Tracking Systems in Construction Waste Logistics Using Optimisation Techniques

Construction waste disposal is an urgent issue for protecting our environment. This paper proposes a waste management system and illustrates the work process using plasterboard waste as an example, which creates a hazardous gas when land filled with household waste, and for which the recycling rate is less than 10% in the UK. The proposed system integrates RFID technology, Rule-Based Reasoning, Ant Colony optimization and knowledge technology for auditing and tracking plasterboard waste, guiding the operation staff, arranging vehicles, schedule planning, and also provides evidence to verify its disposal. It h relies on RFID equipment for collecting logistical data and uses digital imaging equipment to give further evidence; the reasoning core in the third layer is responsible for generating schedules and route plans and guidance, and the last layer delivers the result to inform users. The paper firstly introduces the current plasterboard disposal situation and addresses the logistical problem that is now the main barrier to a higher recycling rate, followed by discussion of the proposed system in terms of both system level structure and process structure. And finally, an example scenario will be given to illustrate the system’s utilization

A study of employees' attitudes towards organisational information security policies in the UK and Oman

There is a need to understand what makes information security successful in an organization. What are the threats that the organization must deal with and what are the criteria of a beneficial information security policy? Policies are in place, but why employees are not complying? This study is the first step in trying to highlight effective approaches and strategies that might help organizations to achieve good information security through looking at success factors for the implementation. This dissertation will focus on human factors by looking at what concerns employees about information security. It will explore the importance of information security policy in organizations, and employee’s attitudes to compliance with organizations' policies. This research has been divided into four stages. Each stage was developed in light of the results from the previous stage. The first two stages were conducted in the Sultanate of Oman in order to use a population just starting out in the information security area. Stage one started with a qualitative semi-structured interview to explore and identify factors contributing towards successful implementation of information security in an organization. The results suggested a number of factors organizations needed to consider to implement information security successfully. The second stage of the research was based on the first stage’s results. After analysing the outcomes from the semi-structured interviews a quantitative questionnaire was developed to explore for information security policy. The findings did suggest that the more issues the organization covers in their security policy the more effective their policy is likely to be. The more an organization reports adoption of such criteria in their security policy, the more they report a highly effective security policy. The more the organization implements the ‘success factors’ the more effective they feel their security policy will be. The third stage was conducted in the UK at Glasgow University because employees are somewhat familiar with the idea of information security. It was based on the findings derived from the analysis of the quantitative questionnaire at stage two. The findings revealed different reasons for employee’s non-compliance to organization security policy as well as the impact of non-compliance. The fourth stage consolidates the findings of the three studies and brings them together to give recommendations about how to formulate a security policy to encourage compliance and therefore reduce security threats

Aspects of Metric Spaces in Computation

Metric spaces, which generalise the properties of commonly-encountered physical and abstract spaces into a mathematical framework, frequently occur in computer science applications. Three major kinds of questions about metric spaces are considered here: the intrinsic dimensionality of a distribution, the maximum number of distance permutations, and the difficulty of reverse similarity search. Intrinsic dimensionality measures the tendency for points to be equidistant, which is diagnostic of high-dimensional spaces. Distance permutations describe the order in which a set of fixed sites appears while moving away from a chosen point; the number of distinct permutations determines the amount of storage space required by some kinds of indexing data structure. Reverse similarity search problems are constraint satisfaction problems derived from distance-based index structures. Their difficulty reveals details of the structure of the space. Theoretical and experimental results are given for these three questions in a wide range of metric spaces, with commentary on the consequences for computer science applications and additional related results where appropriate

LIPIcs, Volume 244, ESA 2022, Complete Volume

LIPIcs, Volume 244, ESA 2022, Complete Volum