Sensors and Actuators in Smart Cities

With the city, from its earliest emergence in the Near East between 4500 and 3100 BCE, came a wide range of new discoveries and inventions, from synthetic materials to wheeled vehicles. Through its dense population, irrigation, social continuity and physical security, emerged civil engineering, monumental construction, sculpture, mathematics, arts and law. Today, there is an enormous set of ideas and notions with respect to our ways of living, e.g., the ramp and the lever, which are still fundamental to cities’ environmental, social, and economic structures. Modern-day smart cities compete for the introduction of smart technologies and applications to improve key areas of urban communities, such as system automation, sustainability, and quality of life. Technology research experts paint thrilling images of futuristic cities. What’s glossed over, however, is the sensor and actuator technologies that enable these smart cities; in particular, the reliable, heterogeneous, wireless networks specifically designed to provision communication across a countless number of sensors embedded in almost everything. The world is on the verge of a new epoch of innovation and change with the emergence of Wireless Sensor Networks (WSN). The convergence of smaller, more powerful processors, smart mobile devices, low-cost sensing, big data analytics, cloud hosting and new levels of connectivity allowed by the Internet is fuelling the latest wave of Machine-to-Machine (M2M) technology. The merits of this marriage of machines and the digital world are multiple and significant. It holds the potential to dramatically alter the way in which most global industries, such as buildings, rail transportation, power grids and healthcare operate on daily basis. WSNs expand to include our vehicles and homes, as well as newly developed wearable and implanted sensors, which brings fundamental transformations to many aspects of daily life. WSN innovations promise to integrate and optimise smart buildings, autonomous vehicles, power grids, etc., to enable a successful transition towards smart, user-driven and demand-focused city infrastructures and services [1,2]. There is a wide range of current smart cities applications, which make our lives easier and more efficient, e.g., a smart phone application that let users find free parking spaces in the centre of town. However, cities are notoriously inefficient. As populations grow, everything from garbage collection and public transport becomes more expensive and complex. Away from increasing spending, there is also a demand from citizens for smarter services driven by sensorand actuator-based infrastructure. In this Special Issue, we accepted submissions that focus on implementing intelligent sensing infrastructure to solve the smart cities conundrum. This Special Issue attracted contributions from academic researchers in computer science, communication engineering and physics, as well as information technology industry consultants and practitioners, in various aspects of sensors and