Design of distributed functional observers for interconnected time-delay systems

This paper considers the design of reduced-order distributed functional observers for interconnected linear systems with the presence of time delays in the interconnections. Unlike observers which consider only the ideal non-delayed output information transfer, the proposed observer is capable of dealing with delayed output information from geographically separated subsystems. It is shown that by accepting measurement data from other subsystems, the conditions under which an observer exists can be made less conservative. Existence conditions, systematic and a straightforward procedure for the synthesis of the observers are given along with numerical examples illustrating the effectiveness and simplicity of the design algorithm.

Privacy protected data forwarding in human associated delay tolerant networks

Human associated delay-tolerant networks (HDTNs) are new networks for DTNs, where mobile devices are associated with humans and demonstrate social related communication characteristics. As most of recent works use real social trace files to study the date forwarding in HDTNs, the privacy protection becomes a serious issue. Traditional privacy protections need to keep the attributes semantics, such as data mining and information retrieval. However, in HDTNs, it is not necessary to keep these meaningful semantics. In this paper, instead, we propose to anonymize the original data by coding to preserve individual's privacy and apply Privacy Protected Data Forwarding (PPDF) model to select the top N nodes to perform the multicast. We use both MIT Reality and Infocom 06 datasets, which are human associated mobile network trace file, to simulate our model. The results of our simulations show that this method can achieve a high data forwarding performance while protect the nodes' privacy as well.

Anonymous data forwarding in human associated delay tolerant networks

Human associated delay-tolerant networks (HDTNs) are new networks for DTNs, where mobile devices are associated with humans and demonstrate social-related communication characteristics. As most of recent works use the social attributes to study the date forwarding in HDTNs and these attributes are critical for the data provider, how to use the anonymous attributes becomes a serious issue. In this paper, we propose a three-dimensional coordinate model by using the anonymous attributes to perform the data forwarding. We use MIT reality dataset, which is a human associated mobile network trace file, to simulate our model. The results of simulations show that the proposed model can use the anonymous attributes to achieve a high data forwarding performance.

Routing and privacy protection in human associated delay tolerant networks

This thesis proposes Human Associated Delay Tolerant Networks, where data communications among mobile nodes are determined by human social behaviours. Three models are proposed to handle the social attributes effect on data forwarding, the time impact on nodes’ movement and the privacy protection issue when social attributes are introduced.

The road map to building new dreams : raising a child with developmental delay or disability

Research on early childhood education emphasises the importance of quality in early childhood intervention. This study examines the quality of Early Childhood Intervention Services based on parents’ experiences raising a child with developmental delay or disability. The study builds on the philosophy of Family-Centred Practice and professionals’ experiences with family-centred interventions. A qualitative case study approach was adopted to gain insight about families who are raising a child with additional needs. Nine in-depth parent-interviews and three focus groups with professionals were conducted in the first two terms of 2010. The case explicates the experiences of parents and professionals who were associated with Specialist Children’s Services in a metropolitan region of Victoria. The research concentrated on the first point of entry to early intervention, the referrals process and the waiting list. It also addressed parents' experiences, priorities and expectations. As a small-scale study, it examined parents’ and children’s needs as well as children’s access to therapy in early intervention. It also investigated community support and parent-professional relationships in the context of early childhood intervention services. The study found that family-centred intervention is beneficial to both parents and children with developmental delay or disability. However, to implement an effective family-centred approach, practitioner support in the form of professional development, supervision and peer mentorship is required to develop professionals’ reflexivity and self-efficacy in family-centred interventions. The study also identified strategies to promote effective practice, gaps in universal and specialised services, and implications for policy.

Examining the viability of windows impact/update method for delay analysis in construction disputes

Nowadays, construction delay disputes often end up on the arbitration route where the delay experts appointed by the parties advise the tribunal on the extension of times entitlements of the parties. For this purpose, the identification and quantification of concurrent and pacing delays are integral aspects of resolving these disputes using a proper delay analysis methodology. The aim of the study is therefore, threefold. Firstly, the available literature on the concurrent and pacing delays are analyzed in detail to establish the principles for the evaluation of the concurrency and pacing delays. Secondly, a robust delay analysis methodology called ‘windows impact/update method’ is explained often used by the experts for the effective quantification of concurrent and pacing delays. This methodology is an improved version of time impact analysis and normal windows analysis. For better demonstration, the explanation of the methodology is facilitated with the help of a typical case study analysis. Finally, the principles of concurrency and pacing, as explained in the literature review, are promptly applied to the case study results to show the applicability of the analysis method on any types of delay disputes. The study shows the effectiveness of the windows impact/update method for the quantification of the concurrent and pacing delays.

ε-bounded state estimation for time-delay systems with bounded disturbances

A new problem on ε-bounded functional state estimation for time-delay systems with unknown bounded disturbances is studied in this paper. In the presence of unknown bounded disturbances, the common assumption regarding the observers matching condition is no longer required. In this regard, instead of achieving asymptotic convergence for the observer error, the error is now required to converge exponentially within a ball with a small radius ε > 0. This means that the estimate converges exponentially within an ε-bound of the true value. A general observer that utilises multiple-delayed output and input information is proposed. Sufficient conditions for the existence of the proposed observer are first given. We then employ an extended Lyapunov-Krasovskii functional which combines the delay-decomposition technique with a triple-integral term to study the ε-convergence problem of the observer error system. Moreover, the obtained results are shown to be more effective than the existing results for the cases with no disturbances and/or no time delay. Three numerical examples are given to illustrate the obtained results.

Approach to fault detection of time-delay systems using functional observers

A new methodology is reported for designing functional observers to detect actuator faults of a class of time-delay systems where the matrix pair (A, C) is not observable. First, a generalised state transformation is used to transform the system into new coordinates where the delay term associated with the state vector is injected into the system's output and input. Then, a minimum-order functional observer is designed to construct a residual function that can trigger system faults. The finding is significant as it is now possible to detect faults of time-delay systems where the pair (A, C) is not required to be observable. A numerical example is given to illustrate the effectiveness of the proposed design approach. © The Institution of Engineering and Technology 2014.