Wireless sensor networks (WSNs) are composed of a large number of sensor nodes and WSNs are often used to monitor hazardous and remote areas. In most situations, the power of the sensors is supplied by the batteries. As a result, the power of the sensors is strictly constrained and energy saving is a big problem. As one of the in-network data processing techniques, data fusion theory is a good solution to reduce the information transmission in WSNs and it can significantly prolong the lifetime of the WSNs. In recent years, data fusion theory in WSNs has been widely researched and applied. However, there are still many challenges that confront researchers.

The aim of this special issue is to present the original research and review articles on the latest theoretical and practical achievements that will contribute to the field of energy-efficient data fusion theory and applications in wireless sensor networks or the related fields.

Potential topics include, but are not limited to:

• Mathematical tools to present imperfect data
• Transformation between mathematical tools
• Clustering algorithms for WSNs
• In-network data processing
• Energy-efficient data fusion technique
• Applications of energy-efficient data fusion theory in WSNs

This special issue aims to foster the latest development in energy-efficient data fusion theory and applications in WSNs. Original contributions that provide novel theories, frameworks, and solutions to the challenging problems are solicited for this special issue.