Introduction to the thematic issue on Natural Interaction in Intelligent Environments

Nowadays, all kinds of smart devices have been networked together and communicated with each other, thereby become an intelligent environment where interaction with the computing devices has become necessity and it happens anywhere anytime. For that reason, human-computer interaction (HCI) has been a lively field of research in the last few years. The aim of HCI research is to provide natural interface when we interact with the intelligent environment. “Natural” here refers to a goal in the user experience – that the interaction can be as natural as interaction with human being, while interacting with the technology, the interface can be used without previous learning. In the past decade, the post-“Windows Icons Menu Pointer” era, many efforts have been devoted in the research of natural interaction. New devices are invented such as interactive walls, muti-touch screen, tablets, smart phones and Xbox Kinect. The growth of embedded and networked devices collectively termed as the ‘Internet of Things’ (IoT) has become an enabler for facilitating richer context awareness and more natural interaction in the intelligent environment. New interaction technologies are explored, such as speech recognition, computer vision, affective interfaces, silent speech, air-writing, gesture-based interaction, Virtual Reality (VR), brain computer interfaces (BCI), and other physiological interfaces such as electrocardiography (ECG), electromyography (EMG), electro-oculography, galvanic skin response (GSR), force, accelerometry, and eye gaze, among many others. These state-of-the-art technologies together with mobile and wearable intelligent devices open up many