## 2 Analysis of the State of the Art
### 2005, [PERSON] and [PERSON]: The Ec(h)o System  
Ec(h)o is an ontology-based augmented audio reality system for museums which aims to maintain rich and adaptive output information. The main purpose of this work is to address the problem of supporting experience design and functionality related to museum visits through user models combined with augmented reality and tangible user interface system. [PERSON] and [PERSON] [22] find several challenges for capturing rich information about the context. For the presented museum scenario, social, cultural, historical and psychological factors are significant for the user experience. In this field the argumentation made by [PERSON] [23,24] is remarked as relevant. [PERSON] states that activities and context are directly and dynamically linked. This concept is called \"embodied interaction\". The core of the ec(h)o's reasoning module is a dynamically updated user model [25]. The ruled-based model changes as the user moves through the museum and selects several audio objects. This models enables developers to consider which inputs influence user interests. In the ec(h)o system there are two ways of updating the model: the user movement and a selection of an audio object. These actions have different effects on the model of the user interests, _i.e_, influence of initial interest selection, of object selection on user interest and of location change. As it occurs with recommender systems, user's interest are vital for the concept ontology. These concepts are weighted in the ontology as concepts which represent the user's likes within the environment. Besides, an interaction history is maintained recording the way the user interacts with the museum. In addition to these characteristics the user type is also considered. This way the system is allowed to characterize the user experience with the environment. It classifies users into three different categories:  
* The avaricious visitor, who wants to see as much as possible in a sequentially way. * The selective visitor, who is more selective with the concepts he/she is interested in. * The busy visitor, who prefers to not spend much time and get a general vision of the exhibition. **2005, [PERSON]**  
Within a video adaptation and quality of experience evaluation scenario, [PERSON] [26] studies a user characterization through three different dimensions: sensorial, perceptual and emotional. First of all, [PERSON] establishes the difference between sensations and perceptions as follows:  
* Sensations are monomodal, more low-level, physical and less related to the real world composition than perceptions. They regard the simple conscious experience for the corresponding physical stimulus, e.g., light variation and eyes reaction to this change. They are related to the first contact between a human and the surrounding environment. * Perceptions are multimodal, and they are part of the cognition process (knowing and learning) and regard the conscious experience and identification of objects. On the other hand, emotions are considered as central in a communication and entertainment process. Therefore, [PERSON] proposes a triple layered sensation-perception-emotion (SPE) user model for the evaluation of the quality of experience in the consumption of multimedia content. **2007, [PERSON] _et al._**  
[PERSON] _et al_. [27, 28] relate user capabilities and product demands as a tool to evaluate the product design. Inclusive design is defined as follows [2]:  
**Definition 3**. : _The design of mainstream products and/or services that are accessible to, and usable by, people with the widest range of abilities within the widest range of situations without the need for special adaptation or design._  
In a particular toaster case study, the sensory, cognitive and motor product demands are compared with different users capability levels.