**5. Acknowledgment**

The development of a new autonomous decentralized control scheme for the long-term operation of wireless sensor networks with multiple sinks represented in this chapter is supported by the Grant-in-Aid for Scientific Research (Grant No.21500082) from the Japan Society for the Promotion of Science.

### **6. References**

Akyildiz, I.; Su, W.; Sankarasubramaniam, Y. & Cayirci, E. (2002). Wireless sensor networks: A survey, *Computer Networks Journal*, Vol.38, No.4, 393-422

*100% line* (*NS* ) *100% line* (

P*roposal* )

*0 1000 2000 3000 4000 5000 6000 7000 The total transmission number of data packets*

In this chapter, a new data gathering scheme with transmission power control that adaptively reduces the load of load-concentrated nodes and facilitates the long-term operation of a large scale and dense wireless sensor network with multiple sinks, which is an autonomous load-balancing data transmission one devised by considering the application environment of a wireless sensor network to be a typical example of complex systems, has been represented. In simulation experiments, the performances of this scheme were compared with those of the existing ones. The experimental results indicate that this scheme is superior to the existing ones and has the development potential as a promising one from the viewpoint of the long-term operation of wireless sensor networks. Future work includes a detailed evaluation

The development of a new autonomous decentralized control scheme for the long-term operation of wireless sensor networks with multiple sinks represented in this chapter is supported by the Grant-in-Aid for Scientific Research (Grant No.21500082) from the Japan Society

Akyildiz, I.; Su, W.; Sankarasubramaniam, Y. & Cayirci, E. (2002). Wireless sensor networks:

*0%*

**4. Conclusions** 

**5. Acknowledgment** 

for the Promotion of Science.

**6. References** 

*20%*

*NS*

*Proposal* (*Te=* 0.0J) *Proposal* (*Te=E* ×0.5J) *Proposal* (*Te=E* ×0.9J)

Fig. 12. Transition of delivery ratio (The number of sensor nodes is 1250 )

of the parameters introduced in this scheme in various network environments.

A survey, *Computer Networks Journal*, Vol.38, No.4, 393-422

*40%*

*60%*

*Delivery ratio (%)*

*80%*

*100%*

*120%*


**0**

**26**

<sup>1</sup>*China* <sup>2</sup>*USA*

**Collaborative Environmental Monitoring with**

<sup>2</sup>*Department of Electrical and Computer Engineering, Michigan Technological University*

In the last decade, advances in wireless communication and micro-fabrication have motivated the development of large-scale wireless sensor networks (Akyildiz et al., 2002; Yick et al., 2008). A large number of low-cost sensor nodes, equipped with sensing, computing, and communication units, organize themselves into a multi-hop network. The wireless sensor network takes measurements from the environment, processes the sensory data, and transmits the sensory data to end-users. Beginning from the seminar work in (Estrin et al., 1999; 2002), the wireless sensor network technology has been well recognized as a revolutionary one that transforms everyday life. Typical applications of wireless sensor networks include military target tracking and surveillance (Simon et al., 2004; He et al., 2006), precise agriculture (Langendoen et al., 2006; Wark et al., 2007), industrial automation (Gungor and Hancke, 2009), structural health monitoring (Li and Liu, 2007; Ling et al., 2009), environmental and

To organize the large amount of sensor nodes and enable efficient data collection, a wireless sensor network generally adopts one of the following three infrastructures: centralized, decentralized, and hierarchical. In the centralized infrastructure, sensor nodes transmit the sensory data to the fusion center via multi-hop communication. In the decentralized infrastructure, each sensor node firstly refines the sensory data through collaborative and decentralized in-network processing with the neighboring sensor nodes, and secondly transmits the refined data to the fusion center. While in the hierarchical infrastructure, sensor nodes are divided into multiple clusters, and sensor nodes within one cluster send their sensory data to the cluster head. These cluster heads either transmit the collected sensory data to the fusion center, or collaboratively process them and transmit the refined one to the fusion center. These two different implementations of the hierarchical infrastructure, centralized

In deploying a wireless sensor network, the choice of its infrastructure is decided by several key factors: energy, bandwidth, robustness, etc. Sensor nodes are often equipped with batteries and recharging is difficult. Since wireless data transmission is the main source of energy consumption of a sensor node (Sadler, 2005), the network infrastructure

habitat monitoring (Zhang et al., 2004; Corke et al., 2010), to name a few.

processing and decentralized collaboration, are depicted in Figure 1.

**1. Introduction**

**1.1 Network infrastructure**

**Hierarchical Wireless Sensor Networks**

<sup>1</sup>*Department of Automation, University of Science and Technology of China*

Qing Ling1, Gang Wu1 and Zhi Tian<sup>2</sup>

