129 resultados para cyber-physical-social systems (CPSSs)

em Deakin Research Online - Australia


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Cyber-physical-social system (CPSS) allows individuals to share personal information collected from not only cyberspace but also physical space. This has resulted in generating numerous data at a user's local storage. However, it is very expensive for users to store large data sets, and it also causes problems in data management. Therefore, it is of critical importance to outsource the data to cloud servers, which provides users an easy, cost-effective, and flexible way to manage data, whereas users lose control on their data once outsourcing their data to cloud servers, which poses challenges on integrity of outsourced data. Many schemes have been proposed to allow a third-party auditor to verify data integrity using the public keys of users. Most of these schemes bear a strong assumption: the auditors are honest and reliable, and thereby are vulnerability in the case that auditors are malicious. Moreover, in most of these schemes, an auditor needs to manage users certificates to choose the correct public keys for verification. In this paper, we propose a secure certificateless public integrity verification scheme (SCLPV). The SCLPV is the first work that simultaneously supports certificateless public verification and resistance against malicious auditors to verify the integrity of outsourced data in CPSS. A formal security proof proves the correctness and security of our scheme. In addition, an elaborate performance analysis demonstrates that the SCLPV is efficient and practical. Compared with the only existing certificateless public verification scheme (CLPV), the SCLPV provides stronger security guarantees in terms of remedying the security vulnerability of the CLPV and resistance against malicious auditors. In comparison with the best of integrity verification scheme achieving resistance against malicious auditors, the communication cost between the auditor and the cloud server of the SCLPV is independent of the size of the processed data, meanwhile, the auditor in the SCLPV does not need to manage certificates.

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This paper presents a distributed multi-agent scheme to detect and identify cyber threats on the protection systems of power grids. The integration of information and communication technologies (ICTs) into existing power grids builds critical cyberphysical energy systems CPESs) in which digital relays are networked cyber-physical components subject to various cyber threats. Cyber attacks on protection systems may mimic real faults, cause component failure, and disable the communication links. Agents utilize both cyber and physical properties to reinforce the detection technique and further distinguish cyber attacks from physical faults. This paper also introduces the problem of secure communicationprotocols and highlights the comparative studies for enhancing thesecurity of the protection systems. The proposed scheme is validatedusing a benchmark power system under various fault and cyber attack scenarios.

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In cyber physical system (CPS), computational resources and physical resources are strongly correlated and mutually dependent. Cascading failures occur between coupled networks, cause the system more fragile than single network. Besides widely used metric giant component, we study small cluster (small component) in interdependent networks after cascading failures occur. We first introduce an overview on how small clusters distribute in various single networks. Then we propose a percolation theory based mathematical method to study how small clusters be affected by the interdependence between two coupled networks. We prove that the upper bounds exist for both the fraction and the number of operating small clusters. Without loss of generality, we apply both synthetic network and real network data in simulation to study small clusters under different interdependence models and network topologies. The extensive simulations highlight our findings: except the giant component, considerable proportion of small clusters exists, with the remaining part fragmenting to very tiny pieces or even massive isolated single vertex; no matter how the two networks are tightly coupled, an upper bound exists for the size of small clusters. We also discover that the interdependent small-world networks generally have the highest fractions of operating small clusters. Three attack strategies are compared: Inter Degree Priority Attack, Intra Degree Priority Attack and Random Attack. We observe that the fraction of functioning small clusters keeps stable and is independent from the attack strategies.

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Machine-to-Machine (M2M) paradigm enables machines (sensors, actuators, robots, and smart meter readers) to communicate with each other with little or no human intervention. M2M is a key enabling technology for the cyber-physical systems (CPSs). This paper explores CPS beyond M2M concept and looks at futuristic applications. Our vision is CPS with distributed actuation and in-network processing. We describe few particular use cases that motivate the development of the M2M communication primitives tailored to large-scale CPS. M2M communications in literature were considered in limited extent so far. The existing work is based on small-scale M2M models and centralized solutions. Different sources discuss different primitives. Few existing decentralized solutions do not scale well. There is a need to design M2M communication primitives that will scale to thousands and trillions of M2M devices, without sacrificing solution quality. The main paradigm shift is to design localized algorithms, where CPS nodes make decisions based on local knowledge. Localized coordination and communication in networked robotics, for matching events and robots, were studied to illustrate new directions.

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Background: The development of new diagnostic technologies for cerebrovascular diseases requires an understanding of the mechanism behind the growth and rupture of cerebral aneurysms. To provide a comprehensive diagnosis and prognosis of this disease, it is desirable to evaluate wall shear stress, pressure, deformation and strain in the aneurysm region, based on information provided by medical imaging technologies. Methods: In this research, we propose a new cyber-physical system composed of in vitro dynamic strain experimental measurements and computational fluid dynamics (CFD) simulation for the diagnosis of cerebral aneurysms. A CFD simulation and a scaled-up membranous silicone model of a cerebral aneurysm were completed, based on patient-specific data recorded in August 2008. In vitro blood flow simulation was realized with the use of a specialized pump. A vision system was also developed to measure the strain at different regions on the model by way of pulsating blood flow circulating inside the model. Results: Experimental results show that distance and area strain maxima were larger near the aneurysm neck (0.042 and 0.052), followed by the aneurysm dome (0.023 and 0.04) and finally the main blood vessel section (0.01 and 0.014). These results were complemented by a CFD simulation for the addition of wall shear stress, oscillatory shear index and aneurysm formation index. Diagnosis results using imaging obtained in August 2008 are consistent with the monitored aneurysm growth in 2011. Conclusion: The presented study demonstrates a new experimental platform for measuring dynamic strain within cerebral aneurysms. This platform is also complemented by a CFD simulation for advanced diagnosis and prediction of the growth tendency of an aneurysm in endovascular surgery.

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The need for guiding model formulation of normative social systems in support of a digital ecosystem is introduced. Normative social systems improve the understanding of computational social processes in simulation and experimentation, and provide support for digital ecosystem developments. However, a successful simulation requires the appropriate implementation of a conceptual model. It is proposed that an heuristic formalism of agents, networks and environments, complements the conventional creative approach to model formulation by guiding the formulation of conceptual models via abstract components and facilitate interface with other components in a digital environment.

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From a future history of 2025: Continuous development is common for build/test (continuous integration) and operations (devOps). This trend continues through the lifecycle, into what we call `devUsage': continuous usage validation. In addition to ensuring systems meet user needs, organisations continuously validate their legal and ethical use. The rise of end-user programming and multi-sided platforms exacerbate validation challenges. A separate trend isthe specialisation of software engineering for technical domains, including data analytics. This domain has specific validation challenges. We must validate the accuracy of sta-tistical models, but also whether they have illegal or unethical biases. Usage needs addressed by machine learning are sometimes not speci able in the traditional sense, and statistical models are often `black boxes'. We describe future research to investigate solutions to these devUsage challenges for data analytics systems. We will adapt risk management and governance frameworks previously used for soft-ware product qualities, use social network communities for input from aligned stakeholder groups, and perform cross-validation using autonomic experimentation, cyber-physical data streams, and online discursive feedback.

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The study investigated two main questions: the first focused on the factors that enabled and constrained student teachers' engagement of a socially critical pedagogy in physical education teacher education (PETE); the second centered on gaining insight into the usefulness of knowledgeability as a concept for analysing student teachers engagement of a socially critical pedagogy. At the time of writing this thesis empirical analyses of socially critical pedagogies in physical education were rare in the educational literature. The study provided an alternative way of analysing student teachers’ engagement of a socially critical pedagogy in PETE. Alternative in that it avoided recycling and reproducing the dualism between agency and structure (Aronowitz and Giroux, 1985) that is prevalent in much of the physical education literature. Conversational interviews were conducted with four student teachers and their teacher educators throughout the duration of a one-semester PETE unit in an Australian university. Observations were made of the lecture and practical sessions and a document analysis was conducted of all unit learning resources. The analytical frame used in the study was structuration theory (Giddens, 1979, 1984). This framework was useful because it gave primacy to the duality of structure which recognised ‘the structural properties of social systems are both the medium and outcome of practices that constitute those systems’ (Giddens, 1979, p.69). The pedagogical intentions of the teacher educator co-ordinating the PETE unit were to change the orientations of the student teachers towards primary school physical education by encouraging them to adopt different ‘lenses’ through which to examine pedagogical practices. These ‘lenses’ highlighted the questions central to those with socio-critical intentions, eg. power, social injustice and diversity. Data generated from conversations with, and observations of, the student teachers, indicated that the actualisation of the teacher educator's intentions were somewhat limited. Despite this, adopting structuration theory as the explanatory framework for the study proved generative at a number of levels. Broadly, structuration theory was useful because it highlighted the way that student teachers' engagement with a socially critical pedagogy is contingent upon particular (idiosyncratic) dialectics of agency and structure. Using the duality of structure as an analytical tool illustrated the way student teachers' were influenced by structural factors as well as the way these structural factors were in turn constituted by the action of the student teachers. Also, by utilising structuration theory as an explanatory framework, the concept of knowledgeability was identified as a useful concept for analysing student teachers' engagement with a socially critical pedagogy in PETE. What is more, the study highlighted the reflexivity of the self and social knowledge, both characteristics of late modernity, as being integral to the way the student teachers engaged with the socially critical pedagogy of EAE400. Not only did the study highlight the reflexivity of the self but it also provided insight into the reflexivity of social knowledge. Much of the socially critical work in physical education implicitly adopts a linear approach to change. Given the findings of the study it might be useful for future developments to consider change as circular. The thesis concludes by suggesting that given the reflexivity of social knowledge, socially critical perspectives might be more readily engaged if the PETE content was incorporated into student teachers existing knowledge frameworks rather than viewed as a replacement for such frameworks.

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In modern computing paradigms, most computing systems, e.g., cluster computing, grid computing, cloud computing, the Internet, telecommunication networks, Cyber- Physical Systems (CPS), and Machine-to-Machine communication networks (M2M), are parallel and distributed systems. While providing improved expandability, manageability, efficiency, and reliability, parallel and distributed systems increase their security weaknesses to an unprecedented scale. As the system devices are widely connected, their vulnerabilities are shared by the entire system. Because tasks are allocated to, and information is exchanged among the system devices that may belong to different users, trust, security, and privacy issues have yet to be resolved. This special issue of the IEEE Transactions on Parallel and Distributed Systems (TPDS) highlights recent advances in trust, security, and privacy for emerging parallel and distributed systems. This special issue was initiated by Dr. Xu Li, Dr. Patrick McDaniel, Dr. Radha Poovendran, and Dr. Guojun Wang. Due to a large number of submissions, Dr. Zhenfu Cao, Dr. Keqiu Li, and Dr. Yang Xiang were later invited to the editorial team. Dr. Xu Li was responsible for coordinating the paper review process. In response to the call for papers, we received 150 effective submissions, out of which 24 are included in this special issue after rigorous review and careful revision, presenting an acceptance ratio of 16 percent. The accepted papers are divided into three groups, covering issues related to trust, security, and privacy, respectively.

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This paper investigates the extent to which the technical and social contexts of organizations independently affect levels of workplace trust. We argue that, in an organizational context, trust is not just a relationship between an individual subject (the truster) and an object (the trustee) but is subject to effects from the conditions of the work relationship itself. We describe the organizational context as comprising both a technical system of production (where work gets done through the specification of tasks) and a social system of work (where problems of effort, compliance, conformity and motivation are managed). We analyse the relationship between trust and these two aspects of workplace context (technical and social systems). We also operationalize this in terms of differences between industries,  occupational composition and human resource management practices. The model is tested using data drawn from the 1995 Australian Workplace Industrial Relations Survey. The results confirm that differences in industry, occupational composition and HRM practices all impact on levels of workplace trust. We review these results in terms of their implications for future research into the problem of analysing variation in trust at both the workplace and individual levels.

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The research program described focuses on identifying the role of organisational culture, as reflected in workplace systems and practices, and employee and group attitudes in the outcomes of interactions among dissimilar parties. A systematic, theory-testing approach underlies the program, which aims to both develop and validate the diversity openness construct. The Perceived Dissimilarity-Openness Moderator Model developed from the research asserts that the affective, cognitive and behavioural consequences of diversity depend in part upon the perception of difference and subsequent quality and magnitude of the response to the perceived dissimilarity. When individuals or social systems (groups or organisations) are diversity-closed, outcomes are predicted to be less positive than when they are diversity-open.

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This paper explores the implementation of a creativity support system for tertiary students studying games design and development at Deakin University, Victoria, Australia. The students at the centre of this study are the ‘next’ generation of learners and are often called the net generation because of their pre-imposed affinity for all things ‘online’. The creativity support system for the games students is designed within a ‘whole’ systems context. Focusing on only one tool to augment a person’s creativity does not take into consideration social factors that are pertinent on a person ability to grow their creative behaviours. This study will present a set of factors that each creativity support system should employ to facilitate creative abilities within people, with particular focus on how social activities help to enhance creativity.

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Physical activity (PA) has consistently been shown to improve ones' physical, social and mental health. Hence, the rationale for promoting regular physical activity is relatively straightforward. However, what is less clear from the literature is the mix of strategies, (i.e. 'what is working and why?'), to increase in physical activity levels within a population. Of particular interest to primary care is the concept of Physical Activity Prescription Programs (PAPPs) delivered by general practitioners (GPs).

Several examples of a PAPP exist within England, America, New Zealand and Australia. These all aim to encourage GPs to deliver physical activity advice to their patients effectively and in a timely manner. Notwithstanding, the authors of a recent review of published literature on PAPPs, reveal a deficit of evidence regarding the components for successful PA interventions.

This research through an ethnographic enquiry aims to build on the evidence formulated to date. Through a case study research design, the researcher has developed a methodology to define what is/is not working within this recent trend.

In two rural Divisions of GP, participants have been identified as key stakeholders in the implementation of a PAPPs. They are categorised according to three theoretical paradigms, namely, Policy Makers, Linkers and Adaptors. Following this the three paradigms will be studied on the contextual factors, the characteristics and behaviours of members within all three paradigms. The study has also further defined certain elements for investigation, these include the:
intention of the players
effort undertaken by players, and
effect of parties within.

Primarily qualitative data will be collected; through Desk Analysis (Policies, Strategic and Business plans), Site Visits (Participant Observation) and semi-structured interviews. This presentation defines a qualitative framework and methodology for investigating the outcome of programs that historically has been evaluated using quantitative measures. Hence, the author of this study aims to present a qualitative investigation and subsequent results, defining aspects of a PAPP that allow for successful and sustainable implementation.