Fagui Liu

An OWL-S based specification model of dynamic entity services for Internet of Things

Semantic Web is an effective technology for intelligent Internet of Things (IoT), where Web Services are commonly used to describe the entity functions in the transaction process. However, as a specification of information processing, conventional Web Services cannot fully meet the needs of execution and control of the transactions on IoT. To facilitate describing entities involved in the transactions on IoT, by extending OWL-S, we propose a specification model of dynamic services for IoT entities. In our model, information of entity status is issued in real-time by the extended structure and is released to the requesters as dynamic services. In this way, the transactions on IoT can be constructed and executed intelligently as needed. Finally, the experimental results demonstrated the effectiveness of the proposed model of dynamic entity services for IoT.

A Xen-Based Data Sharing & Access Controlling Method

The paper begins with introduction on the xen-based secure computer, the common data sharing methods and virtual disk access control. It puts forward a data sharing method based on virtual disk between guest OSs of Full-Virtualization in order to deal with the shortages of data sharing between virtual guest OSs based on Xen secure computer. It induces further analysis on the Xen driver split mechanism inspiring possibility to build a communication channel from guest OS to host OS. Meanwhile, along with the Xen’s virtual disk control principles, a data access control measure is also brought forward. Finally, it proves through a series of precise experiments, the method to be a cross-level data share, which makes data access more controllable and much safer with a promising efficiency beyond other sharing methods.

Ontologies for the transactions on IoT

To facilitate the efficient use of information generated from the Internet of Things (IoT) by sensors and automatically drive entities to meet the needs of human beings, this paper presents an information processing framework using semantic web technologies. The framework represents the entities as semantic web services and automatically creates service sequences as transactions by analyzing the information need in specific queries. Moreover, the framework ensures the effective management and control of information collected by mobile sensors during the transaction. The foundation of this framework lies in a set of ontologies we proposed: goal ontology, role ontology, constraint ontology, message ontology, status ontology, space-time ontology, and activity ontology. In addition to their respective definitions, we also present a detailed exploration of the relationships between them. Finally, we validate the effectiveness of the framework and the ontologies with a case study of the logistics system. The evaluation shows that the ontologies support the framework well and our approach increases the logistics system efficiency with lower operating costs.

Discrete Particle Swarm Optimization Routing Protocol for Wireless Sensor Networks with Multiple Mobile Sinks

Mobile sinks can achieve load-balancing and energy-consumption balancing across the wireless sensor networks (WSNs). However, the frequent change of the paths between source nodes and the sinks caused by sink mobility introduces significant overhead in terms of energy and packet delays. To enhance network performance of WSNs with mobile sinks (MWSNs), we present an efficient routing strategy, which is formulated as an optimization problem and employs the particle swarm optimization algorithm (PSO) to build the optimal routing paths. However, the conventional PSO is insufficient to solve discrete routing optimization problems. Therefore, a novel greedy discrete particle swarm optimization with memory (GMDPSO) is put forward to address this problem. In the GMDPSO, particle’s position and velocity of traditional PSO are redefined under discrete MWSNs scenario. Particle updating rule is also reconsidered based on the subnetwork topology of MWSNs. Besides, by improving the greedy forwarding routing, a greedy search strategy is designed to drive particles to find a better position quickly. Furthermore, searching history is memorized to accelerate convergence. Simulation results demonstrate that our new protocol significantly improves the robustness and adapts to rapid topological changes with multiple mobile sinks, while efficiently reducing the communication overhead and the energy consumption.

Modulization approach & application of OSGi-based RFID Middleware Web presentation layer

The lack of modular technology and framework makes it infeasible for traditional Java-based Web applications to develop in a modular-based way. The integration of OSGi (Open Service Gateway Initiative) framework and Java Web application provides an approach to the modular-based development of J2EE presentation layer, but to cater for the Web presentation layer of enterprise-level Web applications (such as the Web presentation layer of Reconfigurable RFID Middleware), it also requires that OSGi framework can collaborate with J2EE frameworks at all levels. The paper begins with the analysis of the runtime environment of OSGi-based Web applications, which summarizes the technical difficulties when integrating OSGi framework with popular open source J2EE frameworks, and then describes and implements an OSGi DS (Declarative Services)-based Dynamic Perception Model, and applies this model to the development Reconfigurable RFID Middleware Web presentation layer.

Dynamic Context-Aware Event Recognition Based on Markov Logic Networks

Event recognition in smart spaces is an important and challenging task. Most existing approaches for event recognition purely employ either logical methods that do not handle uncertainty, or probabilistic methods that can hardly manage the representation of structured information. To overcome these limitations, especially in the situation where the uncertainty of sensing data is dynamically changing over the time, we propose a multi-level information fusion model for sensing data and contextual information, and also present a corresponding method to handle uncertainty for event recognition based on Markov logic networks (MLNs) which combine the expressivity of first order logic (FOL) and the uncertainty disposal of probabilistic graphical models (PGMs). Then we put forward an algorithm for updating formula weights in MLNs to deal with data dynamics. Experiments on two datasets from different scenarios are conducted to evaluate the proposed approach. The results show that our approach (i) provides an effective way to recognize events by using the fusion of uncertain data and contextual information based on MLNs and (ii) outperforms the original MLNs-based method in dealing with dynamic data.

Optimizing unsatisfactory handover trigger in heterogeneous vehicular networks

In heterogeneous vehicular networks, the communications among moving vehicles (MV) and between vehicles and the roadside infrastructures have posed a challenge for providing continuous mobility services. FMIPv6 looking toward the support of a timely and precise link layer (L2) trigger provides a fundamental mobility management approach. The time stamp of L2 trigger hence is crucial for guaranteeing the handover performance but is difficult to be obtained in the practical application scenarios. The unsatisfactory handover trigger includes the late L2 trigger and the premature L2 trigger. The former would cause a missed detection deteriorating the perceived quality of service, and the latter would cause a false alarm with serious performance loss and resources waste. To address this issue, we propose a solution to optimize the unsatisfactory handover trigger (O-UHT), including promptly determining the unsatisfactory handover trigger and elaborately developing the specific measures to reduce the performance loss caused by the above two cases. The simulations conducted on NS-2 platform have verified the efficiency.

Design and implementation of semantic Web service clustering algorithm

With the development of semantic Web service, the service registry has expanded constantly to cater for new demands. How to improve the efficiency of service discovery is treated as one of the top priorities to be solved. Semantic Web service clustering can organizes and manages the service registry to narrow the scope of service search. This paper has proposed a framework of semantic Web service clustering, designed and implemented an algorithm of semantic Web service clustering by using the Single-Linkage Thinking. This algorithm clusters the services of service registry in order to narrow the scope of service search and improve the efficiency of service discovery. Experimental results show that the clustering framework and algorithm in this paper is efficient, accurate and easy to implement.

Semantic web service matchmaking based on service behavior

Service-Oriented Computing (SOC) is emerging as a new promising computing paradigm. Web service discovery is one of the key issues in SOC. Web service discovery usually provide UDDI as a standard registry which features only keyword-based matches that often give poor performance. Currently approaches for semantic service discovery are mostly limited to the matching of their inputs/outputs possibly enhanced with some ontological knowledge. Recent works have demonstrated that this approach is not sufficient to discover relevant services. In this paper, we argue that in many situations, the service discovery should be based on the specification of service behavior. The idea behind this is to develop matching techniques that operates on behavior models and allow delivery of partial matches. We give the relative definition of our formal model based on Petri nets and WF-nets and propose the transformation from the OWL-S process model into a formal model we defined. And then we define behavior equivalence notion based on our formal model and detail the semantic web service matchmaking algorithm based on that notion.

Application component development of OSGi & JBPM -based RFID middleware

With the daily increasingly wide application of RFID (Radio Frequency Identification) technology, the complexity and diversity of these applications embarks the RFID middleware architecture a prevailing trend. However, the difference among enterprise-level applications increases the difficulty when developing applications above the RFID middleware. This paper presents a solution based on workflow technology, which provides component-based development for RFID middleware applications. It begins with the strategy of component generation and dynamic management based on OSGi (Open Service Gateway Initiative) framework and jBPM (Java Business Process Management) workflow engine. Then it proposes the extraction, generation and dynamic management of RFID application components, which enables component reuse and plug & play in the RFID business process, simplifies the reuse of RFID application workflow. Finally, it validates the proposal via an example of Warehouse Management System based on RFID middleware.