Adapting Technologies to Model Contexts: Two approaches through RFID & NFC

José Bravo(1), Ramón Hervás(1), Gabriel Chavira(2) & Salvador Nava(2)

(1) Castilla-La Mancha University , Spain {jose.bravo,ramon.hlucas}@uclm.es

(2) Autonomous University of Tamaulipas, Mexico {gchavira,snava}@uat.edu.mx

Abstract

The adaptability of sensorial capabilities is

crucial for the performing of daily activities in intelligent environments. There are a number of features that have to be considered, however, in order to avoid constraints of certain technologies. In this work we analyze model and interaction changes using Radiofrequency Identification (RFID) and Near Field Communication (NFC) technologies. When these kinds of technologies are adapted in an attempt to put proactive systems into practice, context-aware applications can suffer some changes; the interaction involved also undergoes changes. Keywords: Ubiquitous Computing, Ambient Intelligence, Context Awareness, RFID, NFC, Visualization Mosaics. 1. Introduction

The Ubiquitous Computing paradigm proposes the idea of placing computational devices around us, in an effort to make the traditional computer disappear. This idea, from Mark Weiser in Xerox Lab, proposes the adaptation of sensorial capabilities as inputs to the system, which means that users may avoid using computers when carrying out some tasks in their traditional daily activities. For that to be the case, some features of intelligent environments need to be studied. The concepts of context and context awareness take into account the idea of this computational dispersion through a whole set of devices which provide users with an intelligent background and which are placed around us. Dey defines context as “any information that can be used to characterize the situation of an entity. An entity is a person, place, or object that is considered relevant to the interaction between a user and an application, including the user and application themselves.” [1], This author highlights three important features and one of these is the device. We have to consider devices to be a product of computer dispersion. Dey also defines context-aware as a “context to provide relevant information and/or services to the user,

where relevancy depends on the user’s task”. Thus we see that it is important to model contexts by equipping them with many kinds of devices.

Under the Sixth and Seventh Framework Programs of the European Community, the concept of Ambient Intelligence (AmI) has come into being. This is a vision in which technology becomes invisible, embedded, present whenever we need it, enabled by simple interactions, attuned to all our senses and adaptive to users and contexts [2].

To design context aware application, it is necessary to see certain types of context-aware information as being more relevant than others [3]. The user profile and situation, the identity, the location of people, the time; these are important concepts that are to be taken into account and all these types of aspects of awareness are included in the five basic questions (Who, Where, What, When and Why), which provide the guidelines for context modeling. New forms of interaction need to be available to cope with all this. Albrecht Schmidt [4] proposes a definition of Implicit Human Interaction: “iHCI is the interaction of a human with the environment and with artifacts, which is aimed to accomplish a goal. Within this process the system acquires implicit input from the user and may present implicit output to the user”. In a subsequent step, Schmidt defines embedded interaction in two terms: embedding technology in daily objects and embedding interaction in daily activities [5].

In this paper we analyze the adaptability of technology and the changes produced in the interactions and models. To do so, we use two identification technologies: Radiofrequency Identification (RFID) and Near Field Communication (NFC).With both technologies, we not only have the advantage of the identification process. There is also the fact that each device (label or tag) can contain certain information which makes it possible to anticipate the user’s needs, when that information is complemented by the context in which the user is found, as well as by the schedule and time. In addition, we give completeness to system interactions by means of other sensorial capabilities.

Under the next heading we present our experience of identification technologies, taking the

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identification process as a good input for intelligent environments. In this section we analyze RFID and NFC technologies. In the following one, a comparison of models and the respective changes in interaction is set out. After this, we present our approach for visualizing information through what we have called “Visualization Mosaics”. In addition, two proposals for the natural interaction board can be seen. The paper finishes with the conclusions that we have drawn. 2. Identification Technologies

To create context-aware applications, sensorial capabilities need to be adapted so as to provide implicit inputs to the system, the aim being to achieve natural interfaces that are closer to the users. This means that the proactive aspect of the system is guaranteed. With this and the ideas of context, together with the characteristics mentioned, we have considered some features of awareness that may change when two different technologies are used.

In the sections following this one, we present RFID and NFC technologies with our proposed models, taking into account the aforementioned “w” question aspects.

Fig. 1.- RFID sets

In Figure 1, some types of RFID devices that we have placed in different contexts can be seen. The first one, on the left, presents a contact reader which is an antenna with a reach of only 10 cm. The second one is another contact RFID set, for identification only. We have developed access control for an office, a classroom and research laboratory. The next one is a reader and an antenna with a read-and-write capability with a reach of over 75 cm. This has been specially designed to be placed on doors, or near displays. Finally, we use another kind of RFID set, offering more distance between reader and tags (up to 88 meters), which works by UHF.

RFID technology offers important advantages over and against the traditional bar codes, transmitting the information in an encrypted way. The embedded interaction consequently comes from user actions such as walking near doors or boards. The reactions of the system are location, access control, presence, inventory, routing phone calls, etc. Other actions such as going into or leaving the room and approaching the board (“proximity”) could be considered as embedded interaction. Both of these put into operation visualization services for users.

The RFID technology had to be adapted to accomplish these goals, but we found some important problems in doing that. One of these is the reading distance. We have been careful in the use

given to each type of RFID set mentioned before, however. While the contact was good for individual use, the other, with a 75cm. reading distance, was ideal for placing on a door or near a board. Another problem was the writing speed. While reading of identification is quick, the process of writing is slow. To solve that, both processes had to be adjusted, filtering the information according to the environment in which the user is located. Another problem associated with this technology is the user data to be stored in the tag. It ranges from a few bytes to 1Kb, though some manufacturers promise 4Kb in each tag.

2.2 The NFC Technology

With the above technology, it is obvious that we need to place a great variety of devices with wireless communication capabilities in the environment around us. Given that fact, new short-range wireless connectivity technology called “Near Field Communications" (NFC), has come into being. Philips and Sony developed this technology, a combination of RFID and interconnection technologies, in 2002.. NFC uses a high frequency band of up to 13.56 MHz, with a data transmission speed of 424 Kbits/s and a reach of 10 cm.

NFC systems consist of two elements, the Initiator, which controls the information exchange and the Target, which responds to the requirement of the initiator.

Fig. 2.- NFC devices and operation modes

In an NFC system, there are two modes of operation: active and passive. In the active one, both devices generate their own field of radio frequency to transmit data (peer to peer). In the passive one, only one of these devices generates the radiofrequency field, while the other is used to load modulation for data transfers.

Figure 2 show three types of NFC devices. The Nokia 6131 mobile phone which is reader-enabled. We also display all the operation modes: mobile phone-tag, mobile phone-mobile phone, mobile phone-reader and reader-tag.

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3. Interaction and model changes

The main goals of this work are, on the one hand, the idea of investigating the way in which interaction of users with computers becomes easier thanks to the identification process, and, on the other hand, the visualization of information through Visualization Mosaics. Our conviction is that visualization of information in a non intrusive way is something that is really necessary for intelligent environments. Interaction is further improved in these when it is done without any explicit interaction. The second technology, NFC, changes the interaction mode with a simple touch. It means that users decide when they want to perform an activity. This aspect makes the context awareness capabilities more flexible and leads to simpler and more feasible applications.

In the next section we analyze both models offered by RFID and NFC technologies, along with the different features that they impose.

3.1 RFID model

The identification of individuals is a very good implicit input to the computer. The simple action of walking near the antenna allows the system to read and write information such as an Id. Number, profile and other very useful items of information which may vary depending on the context where the users find themselves. We have focused the context aspects mentioned before on the identification process [6][7]. We therefore place these concepts strategically, in order to obtain visualization services for the user and aim to make the interaction transparent, non-intrusive and included in the user’s everyday activities. Thus, a user wearing tags and walking through a building can interact with the context without any explicit interaction. He or she can also obtain typical identification services such as location, access, presence, inventory, phone call routing, etc. All of these are obtained by a combination of “who”, “where” and “when” concepts of context.

Our model is based on the concepts mentioned before and keeps in mind the device that the user wears: the tag. In this, it is possible to store some information for context interaction along with that used for identification. This identification and information contained in the tag with “where” and “when” make it possible to offer services to the user. A good example is our proposal of a model in an educational context. Figure 3 shows the classroom as “where” and the schedule as “when”, producing different services: Location, Access, Inventory and the most important for us: Visualization Services through Visualization Mosaics.

Fig. 3.- The RFID - who model

It is obvious that this model requires the presence of a computer to manage the users’ movements and interactions with the environment. For this reason and because of the “w” concepts set out above, it is hard to manage unexpected situations. Despite this, with this technology and model, a natural interaction with the environment is achieved. But an important feature has to be considered: the cost. We have calculated that if we want to put this kind of interaction into practice in a classroom, a single installation will cost over 10.000€. 3.2 NFC model

Some aspects of the model we have commented on above are different when NFC technology is used. Figure 4 shows these changes. As can be seen, the model is completely different from the RFID one. In this case the reader is mobile, with storage, process and communication as autonomous capabilities. In addition, tags can be fixed or mobile. In this model, we consider them to be fixed and to contain contextual information for interaction with mobile phones. The “when” aspect is not needed here, meaning that some responsibilities move to the user, who will take part in the process by means of touch, a fact which allows this model to be more flexible. In addition, the “who” and “what” aspects are combined in the mobile phone. This reads the “where” in tags and makes it possible to obtain services: the main one, included in the tag, and secondary ones included in the user profile. The first one turns the J2ME application included in mobile phone into the specific context profile. That means that all similar applications are included in one group. The second one acts whenever the user chooses the corresponding secondary applications.

Fig. 4.- The NFC model

Figure 5 shows this model in two places: the door and board. The first one is for access as the main

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service and the secondary is for location. In the lower part of the figure, visualization and interaction are presented.

Fig. 5.- NFC services

In this case it is important to mention that some

services can be managed by only a mobile phone and other devices, without computers. For instance, to open a door we only need a door-open control and Bluetooth communications. However, to annex other services like localization, we have to find a nearby computer that supports the server communications, or we may use the GPRS service. Finally, it is important to mention the cost of infrastructure. In this case it is reduced considerably, taking into account the widespread use of mobile phones. By tagging the environment we can achieve a wide range of possibilities of context awareness.

4. Visualization Services

As we mentioned before, one of the most important services in our context is the visualization of information (Visualization Mosaics). Intelligent environments have to be given devices that show information, which has to be presented without intrusiveness and, if possible, without needing the user's request. This presentation and the independence of the display device are important factors that have to be considered. In order to avoid any kind of user interaction, what we try to do is to consider each visualization component as a piece of puzzle. The visualization service is thus regarded as a mosaic of information. For the representation of each mosaic, we have applied an XML-based language, where the pieces of the mosaic, the size and the kind of each element are considered.

Our visualization service involves three modules which are clearly differentiated. They are: The Analysis Context Module, responsible for the changes of the context and the managing of a Data Base, The Mosaic Generation Module, which obtains data that will be presented in the selected mosaic and finally, the Mosaic-Composer Module, which executes the mosaic and generates the user interface automatically.

The activation of each mosaic depends on the input obtained when the system identifies people

wearing rfid tags. Accordingly, the identification, profile, environment, schedule and time are shown by each mosaic, with information adapted to the users. The kind of mosaic also depends on the role assigned according to the context. This role can be presentation in the classroom, research lab, conference contexts, meetings, etc.). The virtual board can show news and notices, information concerning students, research lab members, etc.

With NFC technology the interaction can be produced by means of a tag and contacts with the mobile phone. In this case and for this kind of interaction, the user stores the functionalities of each tag in his profile, All of these models have been built for a university context but we believe it is possible to extrapolate them to other contexts such as health care, business, etc.

In the following sections we present both kinds of interaction commented on before: the infrared sensor combined with RFID technology and the interaction- by-touching tag in the NFC one.

4.2 Infrared Sensor Interaction

It is obvious that in these inputs and outputs some kind of additional interaction is expected. To this end, we have placed some sensors below the visualization device. To be precise, we have four sensors which, with just a movement of the hand, provide some extra functionality, according to the user who is identified. These functions may include, for example, passing a slide, changing tasks, finishing a presentation, etc. With this method there is no need to handle the computer when performing the whole range of simple tasks seen in our contexts.

Fig. 6 shows the architecture. A board enabled with an antenna reading tags and sensors placed below it. The control of sensors is carried out by a Basic X24 circuit and the Bluetooth communication is by means of a Promi ESD circuit. This architecture works through a fusion of the identification process with the functionalities of the sensors. We again highlight the fact that the user’s profile, combined with context, schedule and different hand movements near the sensor (such as passing one’s hand by the sensor, or holding it steady there for a few seconds, etc), make it possible to obtain some extra functionality.

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Fig. 6.- ID-Sensor fusion.

We have to say that, once more, there are some important drawbacks to this architecture that have to be borne in mind. These are its cost, as well as the installation process. The latter involves programming the Basic X24 and connecting with the Promi ESD circuit properly.

4.3 Tagging Interaction

In this case, we have placed some tags on the board, to respond to the interaction that is needed while the information is distributed by our mosaic. Figure 7 shows these tags. One of these is the control tag, with its functionality adapted to each user that takes over.

Fig. 7.- Tagging Interaction Board

Other people can get different functionalities depending on their user profile. In this case, the profile is included in the mobile phone and this sends a signal via Bluetooth to the visualization server,

with the tag touched and the corresponding functionality.

The advantages of this method are clear. The cost is not over-expensive and there is no installation involved, as we just have to place some tags next to the board and write into them the information needed for the interaction. If we need more functionality, all that is required is to place more tags and use the same writing process, because the user functionality is included in the mobile phone application.

6. Related Works

As we mentioned before, a good method for obtaining inputs to the systems comes from the devices that identify and locate people. Want and Hopper locate individuals by means of active badges which transmit signals that are picked up by sensors situated in the building [8]. IBM developed the Blueboard experiment with a display and RFID tag for user collaboration [9]. A similar project is IntelliBadge [10] developed for the academic conference context. There are several works on interaction with public displays by mobile devices [11][12]. However, mobile devices have limitations in their input and output capabilities [13]. NFC can take the advantages of mobile devices and become a valid technology for interacting with devices in the environment, such as displays and boards. Although this technology is recent, there are some interesting papers for discussion. Anokwa [14] presents an NFC model. When a mobile device scans an item with this, the item returns the relevant information needed to describe itself. In Kostakos [15], users with mobile phones encrypt and exchange address book information. An interesting tool for practice can be seen in Toumisto [16], where an emulator for supporting touching, pointing and scanning is presented. This is used to study the feasibility and usability of the context of physical browsing A graphics language is needed to support a visualization for touch interaction and Timo Arnall defines his particular graphic language for touch-based interactions [17].

Public displays have physical characteristics that are different than PCs, so new interaction paradigms are necessary. This is a well-known challenge and several works have done research on this problem. A large number of projects emphasize the use of large interactive/tangible displays (e.g. the interactive workspace project [18]). Another trend is interaction using notebook computers or PDS and techniques like pick-and-drop, i. e. to allow a user to pick up a digital object from one screen, and drop it in a different place, typically a different computer screen or public display [19]. In general, Vogl established a taxonomy of methods for user input to large displays.

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5. Conclusions

We have adapted two technologies with similar characteristics but with different ways of use. In the case of RFID the interaction is natural; the user only has to wear tags to interact with the context, while with the NFC technology, simple interaction by touch is needed. The latter, however, does manifest some clear advantages over the other. We have discussed both models, revealing that the adaptation of technologies produces important changes in context-awareness.

Acknowledgments

This work has been financed by the Ministerio de

Ciencia y Tecnología in Mosaic Learning project 2005-2008 (TSI2005-08225-C07-07).

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[12] Aizawa, K.; Kakami, K.; Nakahira, K. “Ubiquitous Displays for Cellular Phone Based Personal Information Environments”. In: IEEE Pacific Rim Conference on Multimedia (PCM2002). [13] Rukzio, E., Schmidt, a., Hussmann, H. (2004) “An Analysis of the Usage of Mobile Phones for Personalized Interactions with Ubiquitous Public Dis-plays” In: Workshop on Ubiquitous Display Environments in conjunction with UbiComp (Nottingham, UK). [14] Yaw Anokwa, Gaetano Borriello, Trevor Pering & Roy Want. “A User Interaction Model for NFC Enabled Applications”. PERTED Workshop at Per-com 2007. [15] Kostakos, V., O'Neill, E., Shahi, A. (2006). “Building common ground for face to face interactions by sharing mobile device context”. Workshop on Lo-cation and Context Awareness (LOCA 2006), Dublin, Ireland. Lecture Notes in Computer Science 3987, Springer, pp. 222-238. [16] Timo Tuomisto, Pasi Välkkynen, Arto Ylisaukko-oja. “RFID Tag Reader Sys-tem Emulator to Support Touching, Pointing and Scanning”. In proceedings of Mobile Interaction with the Real World (MIRW 2006) [17] Timo Arnall. “A graphic language for touch-based interactions”. In Proceedings of Mobile Interaction with the Real World MIRW 2006). [18] Johanson, B., Fox, A, Winograd, T. (2002) “The Interactive Workspace Project: Experiences with Ubiquitous Computing Rooms”. Pervasive Computing 2(1) pp 71-78 [19] Vogl, S.: Coordination of Users and Services via Wall Interfaces. PhD Thesis. Johannes Kepler. University Linz. 2002.

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