With the development of Internet of Things (IoT), large-scale of resources and applications atop them emerge. However, most of existing efforts are “silo” solutions, there is a tight-coupling... Show More

With the development of Internet of Things (IoT), large-scale of resources and applications atop them emerge. However, most of existing efforts are “silo” solutions, there is a tight-coupling between the device and the application. The paradigm for IoT and its corresponding infrastructure are required to move away from isolated solutions towards cooperative models. Recent works have focused on applying Service Oriented Architecture (SOA) to IoT service provisioning. Other than the traditional services of cyberspace which are oriented to a two-tuple problem domain, IoT services are faced with a three-tuple problem domain of user requirement, cyberspace and physical space. One challenge of existing works is lacking of efficient mechanism to on-demand provisioning the sensing information in a loosely-coupled, decentralized way and then dynamically coordinate the relevant services to rapidly respond to changes in the physical world. Another challenge is how to systematically and effectively access (plug) the heterogeneous devices without intrusive changing. This paper proposes a service provisioning platform which enables to access heterogeneous devices and expose device capabilities as light-weighted service, and presents an event-based message interaction mode to facilitate the asynchronous, on-demand sharing of sensing information in distributed, loosely-coupled IoT environment. It provides the basic infrastructure for IoT application pattern: inner-domain high-degree autonomy and inter-domain dynamic coordination. The practicability of platform is validated by experimental evaluations and a District Heating Control and Information System (DHCIS).

Cloud computing, with characteristics of large scale computation, data storage, visualization, high expansibility and elasticity, provides a powerful computing paradigm. Cloud services can be... Show More

Cloud computing, with characteristics of large scale computation, data storage, visualization, high expansibility and elasticity, provides a powerful computing paradigm. Cloud services can be rapidly composed to form on-demand composite service for accomplishing the users' requirements. However, the uncertainty of cloud services has impacted on the correctness and reliability of the composite services. Especially, for unanticipated hardware and software failures, it is very difficult to assure the quality of the composite services. In the complex cloud computing environments, recovery of the composite services from these failures is a challenging issue. The paper first presents a unified fault taxonomy in the three layers of cloud computing and analyze the causes of the faults. The authors then propose a hierarchical recovery mechanism including five different recovery algorithms for various kinds of failures. Finally, through the simulation experiments they validate the proposed approach to be effective and practical.

A method preserving cyber-physical systems to operate safely in a joint physical space is presented. It comprises the model-based development of the control software and simulators for the... Show More

A method preserving cyber-physical systems to operate safely in a joint physical space is presented. It comprises the model-based development of the control software and simulators for the continuous physical environment as well as proving the models for spatial and real-time properties. The corresponding toolchain is based on the model-based engineering tool Reactive Blocks and the spatial model checker BeSpaceD. The real-time constraints to be kept by the controller are proven using the model checker UPPAAL.

The push services provide an incredibly efficient and reliable way of sending information to mobile device users. However, very little is known about how push service providers implement their... Show More

The push services provide an incredibly efficient and reliable way of sending information to mobile device users. However, very little is known about how push service providers implement their services. This understanding is valuable as a guideline for building well-performing mobile applications. In this paper, the authors propose a methodology to assess push services and conduct the first systematic study on evaluating and comparing 4 popular push services (i.e., GCM, Gexin, JPush, and ZYPush).They dissect the protocols used by these services and discuss the implications. Moreover, they measure and compare their performances, including server distribution, message delay, heartbeat frequency, data compression and traffic consumption. The experimental results show that GCM outperforms others and JPush is one of the best providers in China. The authors' methodology and results are useful as both benchmark and guideline for mobile applications development.

With the growing popularity of cell phones, using massive cellular signaling data as probe to track the vehicles movement trajectory and obtain the real-time traffic condition has become one of the... Show More

With the growing popularity of cell phones, using massive cellular signaling data as probe to track the vehicles movement trajectory and obtain the real-time traffic condition has become one of the most attractive candidate techniques. However, traditional approaches may offer a poor performance in removing noisy data and minimizing deviation of traffic speed in adjacent time intervals. In this paper, a novel approach is proposed to solve these two issues. The authors move noisy data by comparing the cellular signaling data with the trained data set, and adopt a modified Kalman filter algorithm to minimize the deviations. The experiment results show that the accuracy of the approach performs better in comparison to other two traffic speed estimation approaches.