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Having a child with leukaemia requires a high level of care-giving responsibility. Results of existing studies support the theory that hope and spirituality are important to mothers of children with cancer to help them to deal with their child’s diagnosis and illness. Therefore, the purpose of this study was to investigate spiritual health and hope among mothers of children with leukaemia.In this...
Most existing works on data partitioning techniques simply consider to partition data objects and distribute the shares to servers. Such pure data partitioning approaches may bring potential performance and scalability problems when used in widely distributed systems. First, it is difficult to apply lazy update. Second, the share consistency verification may incur costly communications among widely...
In this paper we develop a SCADA key management system to provide better security, performance, and scalability. Conventional symmetric key based approaches have several problems. We adopt public key based approaches due to its flexibility in authentication and access control and efficiency in rekeying. However, existing public key based approaches are not scalable. Simple replication of CAs (certificate...
Many research and development efforts have been devoted towards the design of dependable storage systems, but the effort in evaluating and comparing different designs for widely distributed environment is limited. In this paper, we develop models to evaluate the availability, security, and access performance of various storage designs for the cloud environment where storage resources are offered by...
There have been works considering protocols for accessing partitioned data. Most of these works assume the local cluster based environment and their designs target atomic semantics. However, when considering widely distributed cloud storage systems, these existing protocols may not scale well. In this paper, we analyze the requirements of access protocols for storage systems based on data partitioning...
In cloud computing, data, software, and hardware are wrapped as services, which are made available on demand. Given a demand, the associated services need to interact with each other to fulfill the task. As a result, service reuse and composition are inevitable. The current prevailing Web service composition paradigms follow the bottom-up manner, i.e., the concrete services are physically constructed...
Cyber-Physical Systems (CPSs) are combinations of physical entities controlled by software systems to accomplish specified tasks under stringent real-time and physical entity constraints. As more and more physical entities are equipped with embedded computers, they are becoming more and more intelligent. However, the problem of effectively composing the services provided by cyber and physical entities...
Cyber-Physical Systems (CPSs) are combinations of physical devices controlled by software systems to accomplish specified tasks under stringent real-time and physical resource constraints. The major benefit of these systems lies in their potentially positive impacts on real world systems by enabling high dependability assurance. However, a key challenge is to determine not only correct but also cost-effective...
Autonomous decentralized multi-robot systems require a large number of robots to interact with each other in real-time to cooperatively perform some tasks. This paper systematically investigates the major issues that need to be addressed in methods of building multi-robot based virtual devices. A hierarchical structure is presented to enable the user to tele-control the system when some contingency...
Due to the large number of attacks on open networks, information theft becomes a more and more severe problem. Secure computation can offer highly assured confidentiality protection to critical information and data against external and insider attacks. However, existing secure computation methods are not widely used in practice due to their excessive performance overheads and limited applicability...
Availability analysis is an important issue in robotic swarm systems. It can help the designer to construct a cost-effective system with high availability and fewer resources. For the model and analysis to be fully specified and practical, this paper systematically investigates the major issues that need to be addressed in the analysis of various robotic swarm applications. Four models are established...
We present a fast iterative planner (FIP) that aims to handle planning problems involving nondeterministic actions. In contrast to existing iterative planners, FIP is built upon Graphplan's intrinsic features, thus, enabling Graphplan variants, including SGP and FF, to be enhanced with the capability of iterative planning. In addition, FIP is able to produce program-like plans with conditional and...
Space-division multiple access (SDMA) protocols provide a bounded delay communication medium that is collision free. In these protocols, there is one-to-one mapping between a specific location on the road to a bandwidth division (i.e. a specific timeslot). An implicit assumption is that there is no interference among vehicles traveling on different roads that could be within the sensing range of each...
Software architectures have emerged as a promising approach for managing, analyzing, building, integrating, reusing, and improving the quality of software systems. Specifically, early design decisions can be improved by the analysis of architectural models for different properties. This paper addresses the problem of estimating the reliability of data-flow architectures before the construction of...
In a service chain, one web service invokes another based on the WSDL definition. For some Web services, the invoker may be a user. The ways for a service to interact with an application and a user should be different. When the service interacts with a user, it is preferable to provide a friendly graphical user interface (GUI). Also, users may access a web service from different devices, such as desktops...
High assurance systems have evolving requirements and, hence, the definition for assurance requirements should allow evolution. We recommend the use of ontology to capture such evolving requirements. In this paper, we introduce the concept of trustworthiness to include dependability and some additional high assurance attributes. We develop an ontology of trustworthiness aspects and an ontology of...
Service oriented architecture (SOA) has become a popular paradigm for software development in many application domains, including real-time applications. Timing analysis is a critical issue which can guide service composition to best satisfy the real time requirements of the composed system. However, existing timing analysis works do not sufficiently address some important issues. For example, admission...
In transportation systems, the existing infrastructure can potentially be used more efficiently by deploying intelligent net-centric solutions that coordinate vehicles and traffic signals in real-time. For capacity planning and assessing the cost/benefit tradeoffs of intelligent net-centric coordination infrastructures, it is essential to determine the performance of optimal solutions, i.e., the best...
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