The paper describes the MID-Blue (Multimedia Information Distribution over Bluetooth) system architecture as a dynamic guidance system for museum visitors based on Bluetooth connection. It provides specific contents related to the user position also using streaming video. This feature is still not diffused among Bluetooth technologies and could be more useful than other alternative solutions in museum contexts where it is necessary to delivery short-range information. The architecture overview underlines the components involved for supporting video streaming functionality over Bluetooth describing the first prototype implementation.
This paper describes a dynamic guidance system for museum visitors: MID-Blue (Multimedia Information Distribution over Bluetooth), a mobile Bluetooth based system for managing and providing multimedia information and contents.
Recent studies [
Many applications have been developed for smartphones to give users the
possibility to use geo-localized information: social network (Facebook or four square)
and information provider (Aroundme). Related to the specific context, different
technologies have been used in museums guidance system such as optical signals (i.e.
infrared), and RFID (Radio Frequency IDentification). Each of them has some
limitation that will be describe in the next paragraph. An alternative can be
represented by the Bluetooth technology. It is ideal for use in confined spaces and it
also allows the transmission of data up to the speed of 721 Kbps [
The MID-Blue system introduces an innovative method to provide information through streaming videos on Bluetooth. This is a new feature that is still not so diffused among Bluetooth technologies, and could be very useful for exhibitions in museum where it is necessary to delivery short-range information.
This paper will start from the state of art related to the guidance systems in museum and after that it will describe the MID-Blue project, describing the system architecture and how it can be an alternative valid solution in this specific context. 2
This section defines a first a framework for the application of multimedia technologies in museum contexts. Then it will illustrate the state of art for technologies related to the guidance systems.
Recent studies [
The lack of an adequate information support is the most visible critical issue and
usually one of the first obstacles to increasing the number of museums visitors. A
research of cultural Heritage ministry [
The research of Cultural Observatory of Piemonte show how captions and
information panel are examined on average by half of visitors, while Solima [
50% 50%
Visitors who read Information Panels Visitors don't read Information Panels
This is due to the density of texts and images of panels that causes difficult for
users in reading relevant information. So it can be useful to give information on
multiple level of in-depth examination in order to allow users to have different
information related to specific interests, attention levels and the available time
customized for different targets of visitors. Technologies are perceived as an
opportunity for increasing the quality of life; furthermore young people prefer an
indirect usage of cultural heritage [
Using Smartphone guidance system in museum context can avoid cognitive
overload of visitors, by allowing them to use their own device [
Related to the specific context, different technologies have been used in museum
guidance system such as:
• Optical signals [
Against the others, Bluetooth finds it ideal application in confined spaces, it is
capable of transmitting data up to the speed of 721 Kbps, and it is a global standard
targeted to low cost, small sized, and very low power consumption applications [
The short range distance covered by Bluetooth technologies is useful for delivering the right information related to the objects close to the user, since the system has the possibility to infer (based on signal strength) the distance between the device and the transmitter. These features allow providing specific contents related to the user position.
The MID-Blue system introduces in respect of similar systems [
As described before, this system aims to provide multimedia contents distribution to the users in a small and delimited geographic area (as museum, archaeological area, trading fair, exhibition, etc.) using the Bluetooth connection presents in almost all mobile personal device (smart-phone, cellular phone, PDA, etc.).
The use of Bluetooth connections allows the system to guess how far is the user from the point of interest through the signal strength. In this way the system can provide a list of content only related to what is close to the user (a picture, a statue, a painting, etc.). The use of this system aims at substituting the use of audio/video tours or guides (organization ownership) with the use of personal devices (users ownership) for cultural heritage applications.
Beyond savings in terms of buying and management of equipment, the use of personal devices allows to: • •
Improve the user interaction experience (the user is more confidence using their own device compared to i.e. the museum video guide); Update the multimedia contents very quickly and make them available almost in real time.
From a software perspective, the system involve only Open Source Software (OSS) solutions, allowing to avoid sophisticated constrains related to the licenses management. The multimedia contents managed by the system regards only this three kind of format: • • •
Image;
Video.
The system is based on a client/server architecture in which the server is the multimedia content provider, and the client is the personal device. From the server side we have the following software components:
The architecture design plans the possibility to use more than one server (actually one for each location/room), and each of them is interconnect with the other ones through the Ethernet cable or Wi-Fi network. Each server manages a subset of content related to the location in which it is, in this way the content among the server can be different. Only the information concerning personal devices of the users that agree to interact with the system must be shared among all the servers.
From the client side, the personal device has to have the following software for hosting the client component of the system: • • • • • • • • •
Software to manage the blue-tooth connection (each personal device has one if the blue-tooth characteristic is present); Java support (the MID-Blue client component is a midlet Java application); CLDC Framework 1.1 (Connected Limited Device Configuration - needed to implement the midlet application); MIDP 2.0 profile (Mobile Information Device Profile - needed to implement the midlet application);
OBEX service for file exchange through Bluetooth connection.
Since the exchange of file, as picture or text, by using Bluetooth [
According to the MID-Blue architectural overview shown in Fig. 3, the protocols used for the communication between client and server for provide and use streaming video are: • RFCOMM (Bluetooth) – to exchange message for controlling the video streaming and to send/receive the picture or text file; • OBEX (Bluetooth) – for providing the client application to the personal device; • L2CAP (Bluetooth) – for the video streaming support at layer two; • RTSP (over IP) – streaming protocol.
Using Streaming functionality via L2CAP allows to hide the peculiarities of the Bluetooth low-layers, thus making it possible for existing applications to run over Bluetooth links without deep modifications. In this way it is possible to use streaming client/server application designed to work over the IP protocol, as the RTSP streaming server.
The RTSP1 protocol is based on combination of TCP and UDP protocol over IP: through TCP it is possible exchange messages for controlling the video flow, while UDP transports the real content of video.
Using the Bluetooth as layer-2 connection, the TCP messages can be encapsulated in RFCOMM packets while the UDP video content in L2CAP. This is possible using a proxy on client side as showed in Fig. 3.
On personal device, the proxy service is listening on port 81 for requests from the client media player (i.e. Realplayer2). When a request is received, it activates three
communication channels Bluetooth) in this way: with the
1. TCP – RFCOMM: for the RTSP requests and streaming control 2. Two UDP – L2CAP: for audio and video streaming
On the server side, the MID-Blue Server is listening for request on the above mentioned channel, and upon reception of a request it forwards it to the Darwin Streaming Server, that provides the video/audio streaming service, using two UDP ports for content streaming, and one TCP port (port number 554) for streaming control. 4
This paper briefly describes architecture of the MID-Blue platform, confronting it with the state of the art of similar systems. In particular, the paper describes how the streaming video over Bluetooth is implemented for carrying out the first prototype, and discusses the advantages of this kind of system against other possible alternatives for the provision of multimedia contents for proximity cultural heritage applications.
The MID-Blue project is still underway, therefore the conclusion of development phase and the project validation through experiments or simulations are candidates for future research efforts.