Zhou Xing-she

Context aware sensornet

Advances in MEMS technology, wireless communications, and digital electronics have enabled the development of low-cost, low-power, multifunctional sensor nodes that integrating the ability of sensing, computing, and communication. The low per node cost will enable the development of densely distributed sensornet for a wide range of applications. Sensornet is usually deployed in remote and hostile area without human care. To achieve scalable, robust and long-lived goal, sensornet itself should execute adaptive adjustment and burn energy economically. In this paper we present the idea of context aware sensornet (CASN). Be context aware, sensor nodes are expected to use contexts available and adjust their behaviors correspondingly. Also, cooperative sensor nodes are expected to use context to promote their collaboration. The paper presents the motivation and research challenge of building CASN. It also briefly discusses the implementation issues of CASN middleware.Advances in MEMS technology, wireless communications, and digital electronics have enabled the development of low-cost, low-power, multifunctional sensor nodes that integrating the ability of sensing, computing, and communication. The low per node cost will enable the development of densely distributed sensornet for a wide range of applications. Sensornet is usually deployed in remote and hostile area without human care. To achieve scalable, robust and long-lived goal, sensornet itself should execute adaptive adjustment and burn energy economically. In this paper we present the idea of context aware sensornet (CASN). Be context aware, sensor nodes are expected to use contexts available and adjust their behaviors correspondingly. Also, cooperative sensor nodes are expected to use context to promote their collaboration. The paper presents the motivation and research challenge of building CASN. It also briefly discusses the implementation issues of CASN middleware.

Energy-efficient task allocation for data fusion in Wireless Sensor Networks

Data fusion or In-network processing methods were often adopted in Wireless Sensor Networks (WSNs) to reduce data communication and prolong network lifetime, which made WSNs application can be described as a set of tasks (sensing, processing) and dependencies among them. Task assignment has become an important problem which needed to be resolved for different tasks assignment caused different energy consumption. Based on the task graph of WSNs, an energy-efficient task assignment framework was proposed. As application task can be decomposed into sensing subtasks and processing subtasks, we present the task assignment as sensing subtask assignment and processing subtask assignment. We formulate the processing subtask assignment as a 0–1 quadratic programming problem and evaluate it through experiments.

RBLS: a role based context storage scheme for sensornet

To addressing the self adaptation problem arises from large scale densely deployed sensomet, we argue that integrating the principle of context aware with sensomet is feasible. To build such a context aware sensomet, proper context describing and storing mechanisms must be provided. In this paper, we propose RBLS, a Role Based Local Storage scheme. RBLS is designed simple and energy efficient. Aimed at providing context storage support for sensornet, RBLS stores contexts at nodes local space and dynamically allocates extra spaces according to the roles a node holding. A snapshot is used by RBLS to record a neighbors private contexts. We evaluate the performance of RBLS against a primitive scheme. Simulation results are included in this paper.To addressing the self adaptation problem arises from large scale densely deployed sensornet, we argue that integrating the principle of context aware with sensornet is feasible. To build such a context aware sensornet, proper context describing and storing mechanisms must be provided. In this paper, we propose RBLS, a Role Based Local Storage scheme. RBLS is designed simple and energy efficient. Aimed at providing context storage support for sensornet, RBLS stores contexts at node’s local space and dynamically allocates extra spaces according to the roles a node holding. A “snapshot” is used by RBLS to record a neighbor’s private contexts. We evaluate the performance of RBLS against a primitive scheme. Simulation results are included in this paper.

An Energy Efficient Adaptive Neighbor Detect Protocol for WSNs

Wireless sensor networks lack some basic abilities taken for granted in wired networks, such as the ability to know adjacent nodes. Neighbor protocols are designed to exchange node information for determining which nodes are alive and reachable. This paper introduces the energy efficient adaptive neighbor detect protocol (EEAND), which automatically finds the balance point between energy cost and network connectivity. Towards traditional neighbor detect protocol, EEAND protocol only sends broadcast information when necessary to main topology. According to the SNR of the packets received from neighbor nodes, each node maintains its neighbor table. Simulation studies show that EEAND maintain similar delivery rates while using fewer control packets across a wide range of network characteristics.

A web services-based architecture for capability-aware ubiquitous media

Ubiquitous media aims to provide media services anytime and anywhere. To realize it, one challenge is how to provide customized and dynamic services to a variety of computing devices with different capabilities. This paper presents an architecture, which enables customized delivery of multimedia services. A concept of capability is used to abstract the adaptation-related attributes of computing devices. Capability concerns both the static and dynamic attributes of the computing devices, such as display resolution and remaining battery power. These two classes of attributes can be combined to provide complementary information for customized and dynamic media delivery. As a proof of concept, we have developed a prototype implementation, which is characterized by Web services-based architecture, and capability-aware feature. Our initial experiments show the effectiveness of this architecture.

Using Feedback Control for Notification Service Overload Protection

Notification Service is increasingly being used in a wide variety of distributed computing systems. One problem with Notification Service is that it is sensitive to overload. By analyzing the simulation results of the performance of current Notification Service, we find that the Notification Service needs overload protection. Thus a feedback control based overload protection of Notification Service is presented and designed. Experimental results show that this mechanism can control the load and achieve performance guarantees in the presence of load unpredictability, and it can also ensure allocating and utilizing system resources reasonably and efficiently.