59 resultados para SYSTEMS ANALYSIS


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The overall performance of a distributed system often depends on the effectiveness of its interconnection network. Thus, the study of the communication networks for distributed systems is very important, which is the focus of this paper. In particular, we address the problem of interconnection networks performance modeling for heterogeneous meta-computing systems. We consider the meta-computing system as a typical multi-cluster system. Since the heterogeneity is becoming common in such systems, we take into account network as well as cluster size heterogeneity to propose the model. To this end, we present an analytical network model and validate the model through comprehensive simulation. The results of the simulation demonstrated that the proposed model exhibits a good degree of accuracy for various system organizations and under different working conditions.

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The provision and delivery of many of the services that modern society enjoys are the result of ubiquitous critical infrastructure systems that permeate across many sectors of the Australian community. Moreover, the integration of technological enhancements and networking interconnections between critical infrastructure systems has heightened system interdependence, availability and resilience, including the efficient delivery of services to consumers within Australia's industrialised society. This research delivers a system security analysis and system modelling framework tool based on an associated conceptual methodology as the basis for assessing security and conceptually modelling a critical infrastructure system incident. The intent to identify potential system security issues and gain operational insights that will contribute to improving system resilience, contingency planning development applicable to disaster recovery and ameliorating incident management responses for Australian critical infrastructure system incidents.

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The development and use of cocycles for analysis of non-autonomous behaviour is a technique that has been known for several years. Initially developed as an extension to semi-group theory for studying rion-autonornous behaviour, it was extensively used in analysing random dynamical systems [2, 9, 10, 12]. Many of the results regarding asymptotic behaviour developed for random dynamical systems, including the concept of cocycle attractors were successfully transferred and reinterpreted for deterministic non-autonomous systems primarily by P. Kloeden and B. Schmalfuss [20, 21, 28, 29]. The theory concerning cocycle attractors was later developed in various contexts specific to particular classes of dynamical systems [6, 7, 13], although a comprehensive understanding of cocycle attractors (redefined as pullback attractors within this thesis) and their role in the stability of non-autonomous dynamical systems was still at this stage incomplete. It was this purpose that motivated Chapters 1-3 to define and formalise the concept of stability within non-autonomous dynamical systems. The approach taken incorporates the elements of classical asymptotic theory, and refines the notion of pullback attraction with further development towards a study of pull-back stability arid pullback asymptotic stability. In a comprehensive manner, it clearly establishes both pullback and forward (classical) stability theory as fundamentally unique and essential components of non-autonomous stability. Many of the introductory theorems and examples highlight the key properties arid differences between pullback and forward stability. The theory also cohesively retains all the properties of classical asymptotic stability theory in an autonomous environment. These chapters are intended as a fundamental framework from which further research in the various fields of non-autonomous dynamical systems may be extended. A preliminary version of a Lyapunov-like theory that characterises pullback attraction is created as a tool for examining non-autonomous behaviour in Chapter 5. The nature of its usefulness however is at this stage restricted to the converse theorem of asymptotic stability. Chapter 7 introduces the theory of Loci Dynamics. A transformation is made to an alternative dynamical system where forward asymptotic (classical asymptotic) behaviour characterises pullback attraction to a particular point in the original dynamical system. This has the advantage in that certain conventional techniques for a forward analysis may be applied. The remainder of the thesis, Chapters 4, 6 and Section 7.3, investigates the effects of perturbations and discretisations on non-autonomous dynamical systems known to possess structures that exhibit some form of stability or attraction. Chapter 4 investigates autonomous systems with semi-group attractors, that have been non-autonomously perturbed, whilst Chapter 6 observes the effects of discretisation on non-autonomous dynamical systems that exhibit properties of forward asymptotic stability. Chapter 7 explores the same problem of discretisation, but for pullback asymptotically stable systems. The theory of Loci Dynamics is used to analyse the nature of the discretisation, but establishment of results directly analogous to those discovered in Chapter 6 is shown to be unachievable. Instead a case by case analysis is provided for specific classes of dynamical systems, for which the results generate a numerical approximation of the pullback attraction in the original continuous dynamical system. The nature of the results regarding discretisation provide a non-autonomous extension to the work initiated by A. Stuart and J. Humphries [34, 35] for the numerical approximation of semi-group attractors within autonomous systems. . Of particular importance is the effect on the system's asymptotic behaviour over non-finite intervals of discretisation.

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The decade “Education for Sustainability” is just emerging and one of its goals emphasized the importance of considering the currícula in a transdisciplinary and community based programs. This includes recognizing local and regional interests as relevant topics into the currícula. “Education for sustainability” does not appear to have a strong basis on their actions as its theoretical discourse does. The study we present here about content analysis in the curricula of two high schools systems in rural Mexican communities is an example. In this research we analyzed: 1) how the curricula is oriented towards forest management and the way is connected to the social reality of the communities; 2) how does the learning process develops in the classroom and its dynamics with teachers and students and 3) how does the environmental learning take place. Results revealed that more research is needed with adolescents in order to change the educational structure in rural Mexican high schools.

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Conventional assessments of water quality are based on the determination of bacterial indicator numbers. The detection of an indicator organism only provides presumptive evidence of the presence of harmful organisms By using polymerase chain reaction (PCR) to monitor water quality, indicators and pathogenic organisms can be specifically detected with a high sensitivity. The research illustrates the importance of optimisation and the maintenance of reaction efficiency in the accuracy and precision of the PCR.

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The 3rd generation partnership project (3GPP) long term evolution (LTE) standard uses single carrier frequency division multiple access (SCFDMA) scheme for the uplink transmissions and orthogonal frequency division multiplexing access (OFDMA) in downlink. SCFDMA uses DFT spreading prior to OFDMA modulation to map the signal from each user to a subset of the available subcarriers i.e., single carrier modulation. The efficiency of a power amplifier is determined by the peak to average power ratio (PAPR) of the modulated signal. In this paper, we analyze the PAPR in 3GPP LTE systems using root raised cosine based filter. Simulation results show that the SCFDMA subcarrier mapping has a significantly lower PAPR compared to OFDMA. Also comparing the three forms of SCFDMA subcarrier mapping, results show that interleave FDMA (IFDMA) subcarrier mapping with proposed root raised cosine filter reduced PAPR significantly than localized FDMA (LFDMA) and distributed (DFDMA) mapping. This improves its radio frequency (RF) power amplifier efficiency and also the mean power output from a battery driven mobile terminal.

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Are there differences in commercialization outcomes between universities in Canada and the USA? If so, why? We first examine the commercialization performance of universities on both sides of the 49th parallel through indicators of university spinouts generated. Secondly, we measure the presence and growth in numbers of entrepreneurship centers to determine if there are any parallels or discernable patterns that may be related to spinout performance. Based upon theories that suggest entrepreneurial culture plays a significant role in the spinout process, we then test the hypothesis that entrepreneurship education programs play a significant role in determining spinout performance. Our model assumes that the level and intensity of an academic entrepreneurship program/center is a valid indicator of “entrepreneurial culture” that may impact upon a universities propensity to spinout new knowledge intensive firms. Our results find that there is indeed a correlation between intensity of entrepreneurship program and commercialization outcomes.

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Goal-directed problem solving as originally advocated by Herbert Simon’s means-ends analysis model has primarily shaped the course of design research on artificially intelligent systems for problem-solving. We contend that there is a definite disregard of a key phase within the overall design process that in fact logically precedes the actual problem solving phase. While systems designers have traditionally been obsessed with goal-directed problem solving, the basic determinants of the ultimate desired goal state still remain to be fully understood or categorically defined. We propose a rational framework built on a set of logically interconnected conjectures to specifically recognize this neglected phase in the overall design process of intelligent systems for practical problem-solving applications.

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This paper proposes and applies an alternative demographic procedure for extending a demand system to allow for the effect of household size and composition changes, along with price changes, on expenditure allocation. The demographic procedure is applied to two recent demand functional forms to obtain their estimable demographic extensions. The estimation on pooled time series of Australian Household Expenditure Surveys yields sensible and robust estimates of the equivalence scale, and of its variation with relative prices. Further evidence on the usefulness of this procedure is provided by using it to evaluate the nature and magnitude of the inequality bias of relative price changes in Australia over a period from the late 1980s to the early part of the new millennium.

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The increasing complexity and interconnectedness of critical infrastructure systems, including the information systems and communication networks that support their existence and functionality, poses questions and challenges. Particularly, in terms of modelling and analysis of the security, survivability and ultimately reliability and continued availability of critical infrastructure systems and the services they deliver to modern society. The focus of this research enquiry is with regard to critiquing and modelling critical infrastructure systems. There are numerous systems analyse and modelling approaches that outline any number of differing methodological approaches, each with their own characteristics, expertise, strengths and weaknesses. The intention of this research is to investigate the merit of applying a ‘softer’ approach to critical infrastructure system security analysis and modelling that broadly views the systems in holistic terms, including their relationships with other systems. The intention is not to discuss or criticise existing research applying quantitative approaches, but to discuss a ‘softer’ system analysis and modelling approach in a security context that is adaptable to analysis modelling of critical infrastructure systems.

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Smart Technology involves the integration of a variety of home systems including lighting, climate control, security etc. to enhance the comfort, convenience and economy of the home for its users. It is currently unknown if home buyers believe that these systems add value to the home. This study used the market value of home sales and an attitudinal survey of home buyers, to determine the increased value of homes containing Smart Technology. The results demonstrated that a significant price premium was paid by for the incorporation of the technology into new homes. In addition, the research suggests that the use of this technology is not limited to high income earners or other demographic stereotypes. Instead it has broad market appeal and the potential to save energy for the community at large.

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Smart technology involves the integration of a variety of home systems including lighting, climate control, security etc. to enhance the comfort, convenience and economy of the home for its users. It is currently unknown if homebuyers believe that these systems add value to the home. This study used the market value of home sales and an attitudinal survey of homebuyers, to determine the increased value of homes containing smart technology. The results demonstrated that a significant price premium was paid for the incorporation of the technology into new homes. In addition, the research suggests that the use of this technology is not limited to high-income earners or other demographic stereotypes. Instead it has broad market appeal and the potential to save energy for the community at large.

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Despite the undisputed benefits associated with photovoltaic (PV) technology, the financial barrier acts as the major hurdle before it is seen as a commercial competitive form of renewable energy. Many studies have been performed outlining the life cycle energy benefits of PV technology. However, there has been limited number of studies dedicated to the life cycle cost impacts. The aim of this paper is to identify whether life cycle cost analysis is the best approach to determining the cost contributors or savings associated with this technology. This paper has been structured similarly to previous life cycle energy studies to consider the cost implications involved within each area of the products lifecycle. Amongst many new developments, traditional silicon based units have been challenged by the introduction of new organic systems; and recent studies highlight that these systems offer major cost reductions. Based on an analysis of current literature, this paper identifies that the recent growth and development of both organic and silicon based systems have had a considerable effect on the cost of PV cells. The competitive nature of the renewable energy market will also impact on a life cycle cost analysis; and any potential findings will valid for a limited timeframe.

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A system security analysis and system modelling framework tool is proposed adopting an associated conceptual methodology as the basis for assessing security and conceptually modelling a critical infrastructure system incident. The intent is to identify potential system security issues and gain operational insights that will contribute to improving system resilience, contingency planning, disaster recovery and ameliorating incident management responses for critical infrastructure system incidents. The aforementioned system security analysis and modelling framework is applied to an adverse critical infrastructure system incident case study. This paper reports on the practical application of the framework to a case study of an actual critical infrastructure system failure and the resultant incident implications for the system and the wider regional communities.