Management of SPMD based parallel processing on clusters of workstations

Current attempts to manage parallel applications on Clusters of Workstations (COWs) have either generally followed the parallel execution environment approach or been extensions to existing network operating systems, both of which do not provide complete or satisfactory solutions. The efficient and transparent management of parallelism within the COW environment requires enhanced methods of process instantiation, mapping of parallel process to workstations, maintenance of process relationships, process communication facilities, and process coordination mechanisms. The aim of this research is to synthesise, design, develop and experimentally study a system capable of efficiently and transparently managing SPMD parallelism on a COW. This system should both improve the performance of SPMD based parallel programs and relieve the programmer from the involvement into parallelism management in order to allow them to concentrate on application programming. It is also the aim of this research to show that such a system, to achieve these objectives, is best achieved by adding new special services and exploiting the existing services of a client/server and microkernel based distributed operating system. To achieve these goals the research methods of the experimental computer science should be employed. In order to specify the scope of this project, this work investigated the issues related to parallel processing on COWs and surveyed a number of relevant systems including PVM, NOW and MOSIX. It was shown that although the MOSIX system provide a number of good services related to parallelism management, none of the system forms a complete solution. The problems identified with these systems include: instantiation services that are not suited to parallel processing; duplication of services between the parallelism management environment and the operating system; and poor levels of transparency. A high performance and transparent system capable of managing the execution of SPMD parallel applications was synthesised and the specific services of process instantiation, process mapping and process interaction detailed. The process instantiation service designed here provides the capability to instantiate parallel processes using either creation or duplication methods and also supports multiple and group based instantiation which is specifically design for SPMD parallel processing. The process mapping service provides the combination of process allocation and dynamic load balancing to ensure the load of a COW remains balanced not only at the time a parallel program is initialised but also during the execution of the program. The process interaction service guarantees to maintain transparently process relationships, communications and coordination services between parallel processes regardless of their location within the COW. The combination of these services provides an original architecture and organisation of a system that is capable of fully managing the execution of SPMD parallel applications on a COW. A logical design of a parallelism management system was developed derived from the synthesised system and was shown that it should ideally be based on a distributed operating system employing the client server model. The client/server based distributed operating system provides the level of transparency, modularity and flexibility necessary for a complete parallelism management system. The services identified in the synthesised system have been mapped to a set of server processes including: Process Instantiation Server providing advanced multiple and group based process creation and duplication; Process Mapping Server combining load collection, process allocation and dynamic load balancing services; and Process Interaction Server providing transparent interprocess communication and coordination. A Process Migration Server was also identified as vital to support both the instantiation and mapping servers. The RHODOS client/server and microkernel based distributed operating system was selected to carry out research into the detailed design and to be used for the implementation this parallelism management system. RHODOS was enhanced to provide the required servers and resulted in the development of the REX Manager, Global Scheduler and Process Migration Manager to provide the services of process instantiation, mapping and migration, respectively. The process interaction services were already provided within RHODOS and only required some extensions to the existing Process Manager and IPC Managers. Through a variety of experiments it was shown that when this system was used to support the execution of SPMD parallel applications the overall execution times were improved, especially when multiple and group based instantiation services are employed. The RHODOS PMS was also shown to greatly reduce the programming burden experienced by users when writing SPMD parallel applications by providing a small set of powerful primitives specially designed to support parallel processing. The system was also shown to be applicable and has been used in a variety of other research areas such as Distributed Shared Memory, Parallelising Compilers and assisting the port of PVM to the RHODOS system. The RHODOS Parallelism Management System (PMS) provides a unique and creative solution to the problem of transparently and efficiently controlling the execution of SPMD parallel applications on COWs. Combining advanced services such as multiple and group based process creation and duplication; combined process allocation and dynamic load balancing; and complete COW wide transparency produces a totally new system that addresses many of the problems not addressed in other systems.

Will residential aged care facilities meet long-term demand?

Purpose – This paper aims to provide an invaluable insight into long-term forecasting of demand for aged care facilities. This will ensure the provision of adequate supply by government bodies, stakeholders and developers in order to meet the anticipated level of demand, without creating an over-supply or an under-supply scenario.

Design/methodology/approach – Using an innovative approach, different data sources were collectively used to forecast separate individual supply and demand levels, which were then examined together in order to measure the difference between the two variables between 2009-2020. A case study approach was used for Victoria, Australia.

Findings – The paper finds that, although there is excess supply between 2009-2010 and 2019-2020, the period between 2010 and 2019 will experience an under-supply period which cannot be easily rectified over the short term.

Research limitations/implications – The case study was limited to residential care facilities in Victoria, Australia, although some countries have substantially different age profiles and accommodation supply for older residents. Forecasts are based on information sources from various data suppliers and collectively analysed.

Practical implications – The results are also of direct interest to place managers and planning authorities who are charged with providing medium- and long-term visions and plans for specific locations. This type of research is essential when planning for the eventual aging of the population, where the methodology can be replicated in different areas. Most importantly, this research approach provides a solid basis for decisions regarding the supply of residential aged care facilities as opposed to a simple estimate.

Originality/value – The study adopted a unique approach to analysing the individual supply and demand components for aged care facilities over the long term. This approach is able to accurately determine when there will be an under-supply or over-supply situation and thus provide the opportunity to address the difference before it occurs. This will allow informed decisions about planning aged care facilities in the future to be made as required.

Assurance of corporate social responsibility reports : impact on report users' perceptions of reliability

This study examined whether (1) assurance, (2) the level of assurance (reasonable vs. limited), and (3) the type of assurance provider (accountant vs. specialist consultant) affect users’ perceptions of reliability of sustainability reports. Based on an experimental questionnaire, we find that the provision of assurance improves report users’ perceived reliability of the environmental and social information. There were no significant main effects between the two experimental factors; level of assurance and type of assurance provider, and report users’ perceptions of the reliability of sustainability reports. However, a significant interaction was found between the two experimental factors and report users’ perceptions of reliability of such reports. More specifically, report users placed more confidence in the sustainability reports where the level of assurance provided is reasonable (high), and when such assurance is provided by a top tier accountancy firm, rather than when the assurance is provided by a specialist consultant. No such difference was found when the level of assurance provided was limited (low) for either type of assurance provider group. The results of this study thus highlight the relevance of assurance for sustainability reporting.

Measuring quality of life in alcohol and other drug users - the need for improvement

Objective : The use of Quality of Life (QoL) -related measures in Alcohol and Other Drug-related research has increased dramatically over the past decade. However, there remains a great deal of confusion about which type of QoL measure is most valid, what each constrict actually measures and the ethicality of the process of QoL measurement and its subsequent transfer to monetary value. This is particularly important in regard to subsequent resource allocation on the basis of Quality Adjusted Life Years (QALYs). We aim to review the logic of current QoL -related measurement and determine the most conceptually valid way of measuring QoL.

Methods : This review considers some of the broad principles that concern quality of life assessment. These are discussed in relation to health-related quality of life (HRQoL) and the measurement of subjective well-being.

Results : We argue that there are serious logical and methodological issues concerning HRQoL measurement, to the extent that the instruments may not be regarded as valid measures of life quality as this term is generally understood.

Conclusions : It is recommended that HRQoL measurement be abandoned in favour of three separate forms of measurement as medical symptoms, subjective well-being and specific dimensions of psychological ill-being.

Dancing with death : the grey area between suicide related behavior, indifference and risk behaviors of heroin users

Suicide-related behavior (SRB) among heroin users is a complex and multifaceted continuum, including such fringe areas as indifference and "risky" behavior. The article investigates the nuances and intersections of SRB, using qualitative semi-structured interviews with 60 regular heroin users recruited primarily from syringe programs in Geelong, Australia. Twenty-eight percent of interviewees reported a previous suicide attempt and 45% reported serious consideration of it. Types of SRB reported included: Suicide attempts, instrumental suicide-related behaviors, suicidal ideation, indifference and risk-taking thoughts and behaviors. Heroin users engage in much behavior which inhabits a grey area of SRB. The use of a nomenclature which addresses the elements of lethality and intent improves the ability of research to properly define and categorize SRB in drug-using populations. But the categories should not be overinclusive; indifferent attitudes towards death and risk-taking behaviors can sometimes be a functional response to the risk environment of heroin users.

Scapegoating, self-confidence and risk comparison : the functionality of risk neutralisation and lay epidemiology by injecting drug users

This paper investigates the competing rationalities of scientific and lay epidemiology and how the tension between the two impacts on the efficacy of health promotion messages for injecting drug users (IDUs). It proposes that behaviours, which may be difficult to understand when viewed at an individual level, are, in fact, rational within particular cultural contexts. The study used qualitative semi-structured interviews with 60 heroin users. A number of different types of risk neutralisation were observed in this group of interviewees, including: scapegoating, self-confidence and risk comparison. Interviewees commonly used lay epidemiology to justify and rationalise their risk neutralisation strategies. The paper provides concrete examples of the ways in which this group of IDUs neutralise risk through the use of these strategies. The findings illustrate how many of the psychological constructs surrounding the perception of risk which focus on individual behaviour are fundamentally simplistic and often unhelpful in understanding the behaviours of this group of people. It is concluded that some ‘risk’ behaviours are often functional and rational within the context of prohibitionist drug policies which create an environment in which the IDU often has little real agency to reduce the risks associated with their drug use.

Dancing with death : risk, health promotion and injecting drug users

The thesis investigated ambivalent attitudes towards death in injecting drug users, factors that may lead to such ambivalent attitudes and implications for health promotion campaigns. It was found that this relationship with death was principally attributable to government drug policy in Australia.