Physical selection as tangible user interface

Physical browsing is an interaction paradigm that allows associating digital information with physical objects. In physical browsing, the interaction happens via a mobile terminal - such as a mobile phone or a Personal Digital Assistant (PDA). The links are implemented as tags that can be read with the terminal. They can be, for example, Radio Frequency Identifier (RFID) tags that are read with a mobile phone augmented with an RFID reader. The basis of physical browsing is physical selection - the interaction task with which the user tells the mobile terminal which link the user is interested in and wants to activate. After the selection, an action occurs, for example, if the tag contains a web address, the mobile phone may display the associated web page in the browser. Physical selection is thus a mobile terminal and tag based interaction technique, which is intended for interacting with the physical world and its entities. In ubiquitous computing, the physical environment is augmented with devices offerging digital information and services. Ubiquitous computing can be divided into two broad categories: distributed, in which widgets with user interfaces are embedded into the environment, and mobile terminal centred, in which the user interacts with the devices with a mediator device. In both cases, an important issue in ubiquitous computing is how to interact with the devices embedded into the environment. Physical selection is a direct selection technique for choosing a target in the mobile terminal centred approach. Computer-augmented environment is a concept very similar to ubiquitous computing. The concept grew from the combination of ubiquitous computing and augmented reality, but common to both approaches is the emphasis on the physical world and the tools that enhance our everyday activities. Another concept close to ubiquitous computing and computer-augmented environments is physically based user interfaces, in which the interaction is based on computationally augmented physical artefacts. Tangible user interfaces are based on tangible or graspable physical objects and are thus closely related to physically based user interfaces.