Haigang Gong

An Energy-Aware Protocol for Data Gathering Applications in Wireless Sensor Networks

Data gathering is a major function of many applications in wireless sensor networks (WSNs). The most important issue in designing a data gathering algorithm is how to save energy of sensor nodes while meeting the requirement of applications/users such as sensing area coverage. In this paper, we propose a novel hierarchical clustering protocol for long-lived sensor network. EAP achieves a good performance in terms of lifetime by minimizing energy consumption for in-network communications and balancing the energy load among all nodes. EAP introduces a new clustering parameter for cluster head election, which can better handle the heterogeneous energy capacities. Furthermore, it also introduces a simple but efficient approach, namely intra-cluster coverage to cope with the area coverage problem. We evaluate the performance of the proposed protocol using a simple temperature sensing application. Simulation results show that our protocol significantly outperforms LEACH and HEED in terms of network lifetime and the amount of data gathered.

A Mobility Prediction-Based Adaptive Data Gathering Protocol for Delay Tolerant Mobile Sensor Network

The basic operation of delay tolerant mobile sensor network (DTMSN) is for pervasive data gathering in networks with intermittent connectivity, where traditional data gathering methods can not be applied. In this paper, an efficient mobility prediction-based adaptive data gathering protocol (MPAD) based on the random waypoint mobility model tailored for DTMSN is proposed. In MPAD, a node independently makes decision to replicate messages and send them to the neighbor sensor nodes with a higher probability of meeting the sink node. MPAD consists of two components for data transmission and queue management. Data transmission makes decisions on when and where to transmit data messages according to the node delivery probability, and the queue management employs the message survival time to decide whether the message should be transmitted or dropped for minimizing the transmission overhead. Simulation results show that the proposed MPAD achieves the longer network lifetime and the higher message delivery ratio with the lower transmission overhead and data delivery delay than some other previous solutions designed for DTMSN, such as direct transmission, flooding and message fault tolerance-based data delivery protocol (FAD).

Social Contribution-Based Routing Protocol for Vehicular Network with Selfish Nodes

Routing in vehicular network is a challenging task due to the characteristic of intermittent connectivity, especially when nodes behave selfishly in the real world. Previous works usually assume that all nodes in the network are willing to forward packets for others, which is impractical in real world. Selfish behaviors of nodes would degrade network performance greatly. In this paper, we propose SCR, a social contribution-based routing protocol, for selfish vehicular network. When making forwarding decision, SCR considers both the delivery probability to the destination and the social contributions of the relay node. The delivery probability is determined by the social relations among nodes and social contribution is used as the incentive to stimulate selfish nodes to be more cooperative, which consists of reciprocal contribution and community contribution. The node with higher delivery probability and lower social contributions is the preferred candidate for the next hop. Simulation results show that SCR achieves better performance than other social routing protocols with the incentive scheme.

The last minute: Efficient Data Evacuation strategy for sensor networks in post-disaster applications

Disasters (e.g., earthquakes, flooding, tornadoes, oil spilling and mining accidents) often result in tremendous cost to our society. Previously, wireless sensor networks (WSNs) have been proposed and deployed to provide information for decision making in post-disaster relief operations. The existing WSN solutions for post-disaster operations normally assume that the deployed sensor network can tolerate the damage caused by disasters and maintain its connectivity and coverage, even though a significant portion of nodes have been physically destroyed. In reality, however, this assumption is often invalid for disastrous events like earthquakes in large scale, limiting the relief capability of the existing solutions. Inspired by the “blackbox” technique in flight industry, we propose that preserving “the last snapshot” of the whole network and transferring those data to a safe zone would be the most logical approach to provide necessary information for rescuing lives and control damages. In this paper, we introduce Data Evacuation (DE), an original idea that takes advantage of the survival time of the WSN, i.e., the gap from the time when the disaster hits and the time when the WSN is paralyzed, to transmit critical data to sensor nodes in the safe area. Mathematically, the problem can be formulated as a nonlinear programming problem with multiple minimums in its support. We propose a gradient-based DE algorithm (GRAD-DE) to verify our DE strategy. Numerical investigations reveal the effectiveness of GRAD-DE algorithm.

An Event Driven TDMA Protocol for Wireless Sensor Networks

MAC protocol is the major consumer of sensor energy because it controls the activity of wireless radio of sensor nodes directly. The energy efficiency of MAC protocol makes a strong impact on the network performance. TDMA-based MAC protocol is inherently collision free, and can rule out idle listening since nodes know when to transmit. But traditional TDMA protocol is not suitable for event driven application. In this paper, we present ED-TDMA, an event driven TDMA protocol for wireless sensor network. It improves channel utility by changing the length of TDMA frame according to the number of source nodes and saves energy with bitmap-assisted TDMA schedule. In addition, ED-TDMA employs intra-cluster coverage to prolong network lifetime and to improve system scalability. Simulation results show that ED-TDMA performs better than some other MAC protocol for event driven application in wireless sensor network with high-density deployment and under low traffic.

A distance-aware replica adaptive data gathering protocol for Delay Tolerant Mobile Sensor Networks.

In Delay Tolerant Mobile Sensor Networks (DTMSNs) that have the inherent features of intermitted connectivity and frequently changing network topology it is reasonable to utilize multi-replica schemes to improve the data gathering performance. However, most existing multi-replica approaches inject a large amount of message copies into the network to increase the probability of message delivery, which may drain each mobile node’s limited battery supply faster and result in too much contention for the restricted resources of the DTMSN, so a proper data gathering scheme needs a trade off between the number of replica messages and network performance. In this paper, we propose a new data gathering protocol called DRADG (for Distance-aware Replica Adaptive Data Gathering protocol), which economizes network resource consumption through making use of a self-adapting algorithm to cut down the number of redundant replicas of messages, and achieves a good network performance by leveraging the delivery probabilities of the mobile sensors as main routing metrics. Simulation results have shown that the proposed DRADG protocol achieves comparable or higher message delivery ratios at the cost of the much lower transmission overhead than several current DTMSN data gathering schemes.

RESen: Sensing and Evaluating the Riding Experience Based on Crowdsourcing by Smart Phones

Comfortable travel is an essential issue of Intelligent Transport Systems (ITS). However, the drivers behavior and the road condition affect the comfort of the passengers riding experience while they are traveling. In this paper, we propose a system named Riding Experience Sensor (RESen) for sensing and evaluating the riding experience, based on crowd sourcing by smart phones. We utilize the acceleration sensor and gravity sensor for sensing with arbitrary orientations of smart phones. We partition the riding experience into horizontal and vertical for evaluation. Thus, based on the drivers historical trajectories, the system can provide feedbacks for improving driving by finding the anomalies along these trajectories. Based on the map, which has evaluated the comfort of each road, the system can provide a comfortable travel plan for query users.

Cloud3DView: an interactive tool for cloud data center operations

The emergence of cloud computing has promoted growing demand and rapid deployment of data centers. However, data center operations require a set of sophisticated skills (e.g., command-line-interface), resulting in a high operational cost. In this demo, to reduce the data center operational cost, we design and build a novel cloud data center management system, based on the concept of 3D gamification. In particular, we apply data visualization techniques to overlay operational status upon a data center 3D model, allowing the operators to monitor the real-time situation and control the data center from a friendly user interface. This demo highlights: (1)a data center 3D view from a First Person Shooter (FPS) camera, (2)a run-time presentation of visualized infrastructures information. Moreover, to improve the user experience, we employ cutting-edge HCI technologies from multi-touch, for remote access to Cloud3DView.

Study on Routing Protocols for Delay Tolerant Mobile Networks

Delay tolerant mobile networks feature with intermittent connectivity, huge transmission delay, nodal mobility, and so forth. There is usually no end-to-end path in the networks and it poses great challenges for routing in DTMNs. In this paper, the architecture of DTMNs is introduced at first, including the characteristics of DTMNs, routing challenges, and metric and mobility models. And then, the state-of-the-art routing protocols for DTMNs are discussed and analyzed. Routing strategies are classified into three categories: nonknowledge-based approach, knowledge-based approach, and social-based approach. Finally, some research issues about DTMNs are presented.

An Efficient Data Dissemination Protocol with Roadside Parked Vehicles’ Assistance in Vehicular Networks

Data dissemination is a challenging problem in vehicular ad hoc networks (VANETs) due to the characteristics of VANETs such as highly dynamic topology, intermittent connectivity, and the road-constrained mobility. Observed from the fact that on-street parking is a common phenomenon in the city, the parked vehicles at roadside can also contribute their resources to the communications in network. In this paper, an efficient data dissemination protocol (EDP) for VANETS is proposed. Different from the existing works which consider mainly mobile vehicles or some expensive roadside infrastructure, EDP leverages the resources of parked vehicles at roadside to help in forwarding data. EDP groups the parked vehicles at roadside into a cluster, which buffers and relays data from mobile vehicles and manages the duplicates of data. Simulation results based on a real city map show that EDP achieves a higher delivery ratio and lower delivery delay.