This paper presents Sip4J, a fully automated, scalable and effective tool to automatically generate access permission contracts for a sequential Java program. The access permission contracts, which represent the dependency of code blocks, have been frequently used to enable concurrent execution of sequential programs. Those permission contracts, unfortunately, need to be manually created by programmers, which is known to be time-consuming, laborious and error-prone. To mitigate those manual efforts, Sip4J performs inter-procedural static analysis of Java source code to automatically extract the implicit dependencies in the program and subsequently leverages them to automatically generate access permission contracts, following the Design by Contract principle. The inferred specifications are then used to identify the concurrent (immutable) methods in the program. Experimental results further show that Sip4J is useful and effective towards generating access permission contracts for sequential Java programs. The implementation of Sip4J has been published as an open-sourced project at https://github.com/Sip4J/Sip4J and a demo video of Sip4J can be found at https://youtu.be/RjMTIxlhHTg.

It is expected that muti-core systems will become the dominant computing platform in the next few years. However, the current programming models (such as Java, .Net etc.) do not scale well to exploit the computing power of such multi-core systems. In primitive programming paradigms there exist implicit dependencies between code and program states, and compilers cannot exploit the potential concurrency present in the program unless the programmer introduces concurrency manually using multi-threading, which is prone to errors such as race conditions and deadlocks. The goal of this research is to help programmers achieve concurrency without mastering the intricacies of this domain. We propose a formal technique and a high-level algorithm to extract implicit dependencies from a sequential Java program in the form of access permission rights. The proposed technique performs static analysis of the source code on a modular basis. The inferred permissions can potentially be used by runtime engines such as Java Virtual Machine (JVM) to automatically parallelize sequential programs on multi-core systems and to reason about concurrency.

Internet of Things (IoT) represents a cyber-physical world where physical things are interconnected on the Web. This paper presents an architecture designed for Energy-efficient Inter-organizational wireless sensor data collection Framework (EnIF). Environmental monitoring and urban sensing are two major application scenarios in IoT. Different from the traditional sensor environments, environmental sensing in IoT may require battery-powered nodes to perform the sensing tasks. Such a requirement raises a critical challenge to ensure that sensor data gathering can be collected in a timely and energy-efficient manner. Although numerous energy-efficient approaches for IoT scenarios have been proposed, previous works assumed the entire network was managed by a single organization in which the network establishment and communication have been pre-configured. This assumption is inconsistent with the fact that IoT is established in a federated network with heterogeneous devices controlled by different organizations. The aim of the framework is to enable a dynamic inter-organizational collaborative topology towards saving energy from data transmissions using a service-oriented architecture.

Mobile devices are capable of acting as smart assistances not only to serve their users but also to collaborate with each other remotely via wireless Internet to accomplish common goals. The latter is achieved by establishing a Social Private Cloud (SPC). SPC is a cluster formed by a scalable group of social network participants using their mobile devices that are capable of providing their resources to accomplish computational tasks. In this paper, we propose a workflow-based SPiCa framework that enables task delegation in SPC. In order to support adaptive task scheduling based on resource availabilities, a resource-aware task scheduling scheme has been proposed and implemented as a proof of concept. The evaluation demonstrates that the framework is capable of dynamically reacting to runtime changes in order to adjust the task delegation process.

What if physical artifacts or devices can be aware of each others' physical presence and location, and interact with each other without user intervention or to enable innovative applications? We propose a model for devices to manage awareness of each other, extending a spatial model of interaction previously used in virtual environments. While there has been previous work on cooperative artifacts, our model is unique in introducing a quantitative technique. Moreover, our model is novel in adding to proximity-based interactions among devices the concepts of the following: 1) aura collision types based on relative locations of devices and 2) multiple (adjustable) levels of awareness and concealment measures so that each device can control how much it wants to be aware of others and how much it wants to be concealed from others. Our model is general and supports awareness of devices in (sufficiently) close physical proximity and the right aura sizes. Such devices' awareness of each other facilitates or triggers interaction, and normally precedes interaction among devices (as in human communication). Our model has numerous applications, from smart soft-toy features to proximity-triggered data exchanges.

Advances in wireless and sensing technology and the proliferation of context-aware systems have highlighted the requirement to reduce the complexity of system development by establishing a middleware framework of context management. The middleware aims to manage different aspects of context and location management as well as situation reasoning and other related tasks. In this paper, a middleware framework of context management and situation reasoning in MANET environment is proposed. It includes components to model and reason about contexts and situations, to construct location models and estimate the relevance of contexts used for situation reasoning. We also incorporate On-Demand Multicast Routing Protocol (ODMRP) as the underlying messaging protocol among the collaborative hosts to deal with MANET communication issues. We discuss implementation and experimentation issues of the framework in personal digital assistance (PDA) devices which form the ad hoc network as proof-of-concept of the framework. Our preliminary implementation and experimentation shows the capability of the framework to work in such limited devices and to perform the designed capabilities of the middleware.

Due to its ability to provide high-performance computing environment, the grid has become an important infrastructure to support eScience. To utilise the grid for parameter sweep experiments, workflow technology combined with tools such as Nimrod/K are used to orchestrate and automate scientific services provided on the grid. As parameter sweeping over a workflow needs to be executed numerous times, it is more efficient to execute multiple instances of the workflow in parallel. However, this parallel execution can be delayed as every workflow instance requires the same set of resources leading to resource competition problem. Although many algorithms exist for scheduling grid workflows, there is little effort in considering multiple workflow instances and resource competition in the scheduling process. In this paper, we proposed a scheduling algorithm for parameter sweep workflow based on resource competition. The proposed algorithm aims to support multiple workflow instances and avoid allocating resources with high resource competition to minimise delay due to the blocking of tasks. The result is evaluated using simulation to compare with an existing scheduling algorithm.

The emergence of context-aware systems has highlighted the requirement to reduce complexity in developing the systems by establishing a context middleware. The middleware aims to provide support for managing context independently from applications and enhance generality and reusability of context sources for multiple applications. In this paper we propose a novel framework for managing context in mobile ad hoc network environment (MANET). We model contexts and situations based on the concept of situation space in Context Spaces theory and integrate the model with Dempster-Shafer rule of combination for situation reasoning. Furthermore, we incorporate reliability of information in the fusion mechanism based on discount rule to adopt uncertainty factor that may exist due to limited and uncertain evidence in the hostpsilas environment. Finally, the implementation and experimentation issues of the prototype are also discussed.

The operations of devices in an environment can be specified by user-defined service-oriented workflows. During the workflow execution of these devices, potential device failures can occur on-the-fly. This paper proposes a framework based on context-awareness towards resolving such failures. The framework aims to provide a solution for failure detection, a recovery algorithm and a rule-based device substitution approach to discover the best substitute based on the current contexts.

We propose a conceptual framework to describe and understand mobile information environments. In our proposal, such an environment can be categorised into different abstraction levels or communities: user level, workflow level, device level and architecture level. A hospital-based example is then used as an illustration for the proposed framework.

Recently, workflow has been employed in pervasive computing systems to orchestrate and provide services to the users. Since pervasive computing systems emphasise context-awareness and adaptability, these two features must be included in the workflow mechanism in order to utilise workflow in pervasive environment. In this paper we present various existing approaches to adaptation in context-aware workflow. These approaches are compared based on the common adaptation characteristics identified from our study. Lastly, we discuss and point out the future challenges of predictive adaptation for context-aware workflows.

Time management in workflow processes is crucial in determining and controlling the life cycle of business activities. In our model, a temporal interval as an execution duration is assigned to every workflow task. While the real time taken by the task is nondeterministic and unpredictable, it may be between the bounds thus specified. We extend workflow nets (WF-nets) with time intervals and call the new nets Time WF-nets (TWF-nets). Extending our previous results on timed Petri nets, we show that certain behavioural properties of workflow processes modelled in TWF-nets can be verified. Using a clinical health care process as a case study, we also illustrate the modelling of shared resources available at different times.