Decheng Zuo

Modeling of Node Energy Consumption for Wireless Sensor Networks

Energy consumption is the core issue in wireless sensor networks (WSN). To generate a node energy model that can accurately reveal the energy consumption of sensor nodes is an extremely important part of protocol development, system design and performance evaluation in WSNs. In this paper, by studying component energy consumption in different node states and within state transitions, the authors present the energy models of the node core components, including processors, RF modules and sensors. Furthermore, this paper reveals the energy correlations between node components, and then establishes the node energy model based on the event-trigger mechanism. Finally, the authors simulate the energy models of node components and then evaluate the energy consumption of network protocols based on this node energy model. The proposed model can be used to analyze the WSNs energy consumption, to evaluate communication protocols, to deploy nodes and then to construct WSN applications.

Intelligent Urban Public Transportation for Accessibility Dedicated to People with Disabilities

The traditional urban public transport system generally cannot provide an effective access service for people with disabilities, especially for disabled, wheelchair and blind (DWB) passengers. In this paper, based on advanced information & communication technologies (ICT) and green technologies (GT) concepts, a dedicated public urban transportation service access system named Mobi+ has been introduced, which facilitates the mobility of DWB passengers. The Mobi+ project consists of three subsystems: a wireless communication subsystem, which provides the data exchange and network connection services between buses and stations in the complex urban environments; the bus subsystem, which provides the DWB class detection & bus arrival notification services; and the station subsystem, which implements the urban environmental surveillance & bus auxiliary access services. The Mobi+ card that supports multi-microcontroller multi-transceiver adopts the fault-tolerant component-based hardware architecture, in which the dedicated embedded system software, i.e., operating system micro-kernel and wireless protocol, has been integrated. The dedicated Mobi+ embedded system provides the fault-tolerant resource awareness communication and scheduling mechanism to ensure the reliability in data exchange and service provision. At present, the Mobi+ system has been implemented on the buses and stations of line ‘2’ in the city of Clermont-Ferrand (France). The experiential results show that, on one hand the Mobi+ prototype system reaches the design expectations and provides an effective urban bus access service for people with disabilities; on the other hand the Mobi+ system is easily to deploy in the buses and at bus stations thanks to its low energy consumption and small form factor.

Real-Time Automatic ECG Diagnosis Method Dedicated to Pervasive Cardiac Care

Recent developments of the wireless sensor network will revolutionize the way of remote monitoring in dif-ferent domains such as smart home and smart care, particularly remote cardiac care. Thus, it is challenging to propose an energy efficient technique for automatic ECG diagnosis (AED) to be embedded into the wireless sensor. Due to the high resource requirements, classical AED methods are unsuitable for pervasive cardiac care (PCC) applications. This paper proposes an embedded real-time AED algorithm dedicated to PCC sys-tems. This AED algorithm consists of a QRS detector and a rhythm classifier. The QRS detector adopts the linear time-domain statistical and syntactic analysis method and the geometric feature extraction modeling technique. The rhythm classifier employs the self-learning expert system and the confidence interval method. Currently, this AED algorithm has been implemented and evaluated on the PCC system for 30 patients in the Gabriel Monpied hospital (CHRU of Clermont-Ferrand, France) and the MIT-BIH cardiac arrhythmias da-tabase. The overall results show that this energy efficient algorithm provides the same performance as the classical ones.

An Optimal Sink Selection Scheme for Multi-sink Wireless Sensor Networks

Wireless sensor networks consist of sensor nodes and sink nodes. Due to the variety of applications, the interconnection between wireless sensor networks and Internet is needed. In order to have the access to the Internet, a sensor node must select a sink node as the gateway to the Internet. The selection of sink has great influence on the delivery latency and network efficiency. In this paper, we present a novel sink selection scheme which take transmission latency and sink forwarding latency into consideration. The optimal sink for the sensor node is the closest sink that has the least wait send packets. Simulation results demonstrate that this scheme has a low sink discovery overhead, a low end-to-end packet delivery latency, and a good packet delivery ratio.

Energy Consumption Evaluation for Wireless Sensor Network Nodes Based on Queuing Petri Net

Due to the large scale of wireless sensor networks (WSN) and the huge density of WSN nodes, classical performance evaluation techniques face new challenges in view of the complexity and diversity in WSN applications. This paper presents a “state-event-transition” formal description for WSN nodes and proposes an event-driven QPN-based modeling technique to simulate the energy behaviors of nodes. Besides, the framework architecture of a dedicated energy evaluation platform has been introduced, which can be used to simulate the energy consumption of WSN nodes and to evaluate the system lifetime of WSN. Case studies prove that this platform can be utilized for the selection of WSN nodes and network protocols, the deployment of network topology, and the prediction of system lifetime as well.

Research on Routing Protocol of Wireless Ad Hoc Network Based on Wearable Computers

Wearable computers need networking by using wireless ad hoc network in order to utilize them more effectively, routing protocol becomes an important research field for its significance in wireless ad hoc network. In Ad Hoc network, there are mainly two kinds of routing protocols: proactive routing protocol and on-demand routing protocol, to evaluate the performance of two kinds of protocols, we choose two representative protocols, DSDV and AODV, and implement network simulations with OPNET. Packet delivery ratio, average end-to-end delay and energy consumption are analyzed and compared by changing node¿s speed, the interval of sending packet and initial energy. Simulation results demonstrate that on-demand routing protocol is suitable for the wearable computer network where energy supply is limited, topology changes a lot or communications frequently, and proactive routing protocol is suitable for the wearable computer network where high real time is required.

A Decentralized Compositional Framework for Dependable Decision Process in Self-Managed Cyber Physical Systems

Cyber Physical Systems (CPSs) need to interact with the changeable environment under various interferences. To provide continuous and high quality services, a self-managed CPS should automatically reconstruct itself to adapt to these changes and recover from failures. Such dynamic adaptation behavior introduces systemic challenges for CPS design, advice evaluation and decision process arrangement. In this paper, a formal compositional framework is proposed to systematically improve the dependability of the decision process. To guarantee the consistent observation of event orders for causal reasoning, this work first proposes a relative time-based method to improve the composability and compositionality of the timing property of events. Based on the relative time solution, a formal reference framework is introduced for self-managed CPSs, which includes a compositional FSM-based actor model (subsystems of CPS), actor-based advice and runtime decomposable decisions. To simplify self-management, a self-similar recursive actor interface is proposed for decision (actor) composition. We provide constraints and seven patterns for the composition of reliability and process time requirements. Further, two decentralized decision process strategies are proposed based on our framework, and we compare the reliability with the static strategy and the centralized processing strategy. The simulation results show that the one-order feedback strategy has high reliability, scalability and stability against the complexity of decision and random failure. This paper also shows a way to simplify the evaluation for dynamic system by improving the composability and compositionality of the subsystem.