LOCATION BASED GUIDANCE SERVICES IN A MUSEUM

ENVIRONMENT: DEPLOYMENT ISSUES AND A PROPOSED

ARCHITECTURAL APPROACH

Anastasios Zafeiropoulos, Emmanuel Solidakis, Stavroula Zoi, Nikolaos Konstantinou

Panagiotis Stathopoulos and Nikolas Mitrou

National Technical University of Athens,

Heroon Polytechneiou Str., 15773 Zografou, Athens, Greece

Keywords: Location Based Guidance Services, Museum, Smart phones, Bluetooth, GPS, Web technologies, Ajax

applications.

Abstract: In this paper we examine the requirements for deploying advanced Location Based Guidance Services in

museum and/or exhibition environments, and we propose an architectural approach that copes with these

requirements. The proposed architecture provides automatic and on demand audiovisual content retrieval,

both on-site and through the Web, to different classes of users. On-site services are provided through Java-

enabled devices, which exploit the user’s contextual state, mainly defined as visitor location and

organization of exhibits. The main distinguishing characteristic of the proposed architecture is that it

separates the positioning system from the content access mechanisms, while being generic to the selection

of the localization technology and the terminal device characteristics. Furthermore, it is built as an open,

modular platform comprising a core of reusable components and interfaces for supporting different types of

services and devices, including widespread Java and Bluetooth enabled smart phones, while being able to

reuse already existing content structures. A test case of a museum e-guidance application for Bluetooth

enabled smart phones is presented.

1 INTRODUCTION

One of the key technologies underpinning

ubiquitous computing is that of location based

services (LBS). Location-aware systems react not

only to the users’ input but also to contextual events

from the users’ environment. The designers have to

carefully balance the way in which such systems

react to environmental triggers (Yo-Ping Huang &

Wei-Po Chuang, 2004). The museum domain has

been one of the most considerable target domains

where LBS are applicable for on-site guidance. In

this case, mobile users who need context-dependent

information should not be disoriented from the

museum information (Carmine Ciavarella & Fabio

Paterno, 2003).

According to (Stefan Steiniger, Moritz Neun &

Alistair Edwardes, 2006), LBSs are information

services accessible with mobile devices through a

mobile network and utilizing the ability to make use

of the location of the mobile device. If the user

wants to use a location based service, different

infrastructure elements are necessary.

In Figure 1 the basic components and their

connections are shown:

Figure 1: Basic LBS Components.

• Mobile Devices: The terminal device that

presents the content to the end-user. Possible

devices are PDA's, Mobile Phones, Laptops.

• Communication Network: The IP Network,

used for exchange of data between the mobile

terminal and the service provider.

217

Zafeiropoulos A., Solidakis E., Zoi S., Konstantinou N., Stathopoulos P. and Mitrou N. (2007).

LOCATION BASED GUIDANCE SERVICES IN A MUSEUM ENVIRONMENT: DEPLOYMENT ISSUES AND A PROPOSED ARCHITECTURAL

APPROACH.

In Proceedings of the Second International Conference on Wireless Information Networks and Systems, pages 201-208

DOI: 10.5220/0002148402010208

 SciTePress

• Positioning Component: The Component used

for the selection of the suitable localization

technique.

• Service and Application Provider: The

service provider which offers a number of

different services to the user and is responsible

for the service request processing.

• Data and Content Provider: The Content

Management System that maintains all the

museum information which can be requested by

users.

In order to develop a platform to provide LBS,

the following requirements need to be fulfilled, as

described in (Sebastian Herden, Arman Mkrtchyan,

Claus Rautenstrauch, Andrι Zwanziger & Michael

Schenk, 2003): terminal independence, simple user

interface, minimal communication over mobile

telephone networks, integration of mobile devices,

simple integration of existing Internet services, high

availability of the services even at high loads,

scalability, openness (support common standards

and protocols), and low costs. Furthermore, in

(Carmine Ciavarella & Fabio Paterno, 2003) there

are analyzed the design criteria to use when

developing location-aware indoor mobile

applications. The most important of them are the

following: easy navigation through web browsers,

navigation feedback and minimal graphical

interaction, orientation support in the surrounding

environment and minimum redundancy in input

commands.

As far as the museum domain is concerned, the

term electronic-museum may include different

concepts, and corresponding technologies, which till

recently ranged mainly from “in museum” content

presentation (e.g. by exploiting virtual reality and

immersion technologies), to content publishing

through the museum’s web site. The evolution of

position tracking technologies and LBS has given

new possibilities of both indoor and outdoor context

aware guidance systems. Through such a context-

aware guidance system, the visitors in a museum can

receive location-based content immediately, even

through their own handheld devices (e.g. mobile

phones) in order to enhance visiting experience. In

this case, simple interfaces for content searching and

retrieval should be provided in order to appeal also

to users not familiar with technology (e.g. children)

and in order not to disrupt the user from focusing on

the exhibits themselves. Furthermore, any platform

arrangements (e.g. cables, servers, receivers) should

not distort the physiognomy of the museum. The

guidance system infrastructure should be easily

deployable to different exhibit topologies and

already existing content structures (e.g. Content

Management Systems).

Museum visitors can be classified to different

levels, first of all, according to their interests and

background, ranging from children and regular

visitors, to professionals and researchers. Each of

them demands a different level of knowledge and

detail. Furthermore, museum users can be classified

according to the terminal device they possess. For

example, laptop users may be able to get full

versions of the content (e.g. 3D models, detailed

maps), while small devices (e.g. smart phones or

Personal Digital Assistants) users may be able to

acquire a limited version of the content on-site, but

they may ask for an enhanced version for off line

usage (e.g. stored in a CD). In general, any guidance

system should be flexible as far it concerns serving

different classes of users.

Based on the above observations, we present a

lightweight approach for providing location aware

multimedia content retrieval, through Java enabled

handheld devices. The main distinguishing

characteristic of the proposed approach is that it

separates the positioning system from the content

access mechanisms, while being generic to the

selection of the radio localization technology. So far,

interfaces are provided for Bluetooth and Infrared

for indoor environments, as well as for GPS for

outdoor environments, while others can be

developed, e.g. RFID. Furthermore, it is built as an

open, standards-based, modular architecture

comprising a core of reusable components and

interfaces for supporting different types of services,

through web technologies.

A main characteristic of the proposed approach

is that it has minimum mobile device requirements,

since it operates in all java enabled mobile devices.

Therefore, only a Java middlet and a web browser

need to be installed in the mobile device, while, in

the backend what is required is an HTTP server and

Content Management System (CMS) which can be

determined independently. The components of the

proposed approach ensure modularity, in that

different types of services can be easily supported

for different groups of users. Finally, flexible

mechanisms, for adapting to most museums needs

are present, in regard to the physical platform,

computing and communication resources, to the site

configuration and set up and to the user equipment.

WINSYS 2007 - International Conference on Wireless Information Networks and Systems

218

2 LBS MECHANISMS AND

THEIR MUSEUM

APPLICATIONS

2.1 Position Tracking Technologies

The identification of a user’s position can be

performed at various levels of granularity: for

example, one is the identification of the exact user

position, thus, in a museum application, the system

can identify the closest work of art; another level is

when the system is only able to identify the room

where the user is located.

Position tracking technologies aim to measure

the movement of the mobile terminal. These

technologies provide great accuracy, but are limited

in terms of geographic coverage. To explicitly

localize the users in indoor applications, three recent

technologies are mainly exploited: WLAN,

Bluetooth and Infrared. In (Carmine Ciavarella &

Fabio Paterno, 2003) advantages and disadvantages

of each of them are highlighted. In the next

paragraph we provide an overview of these

technologies.

WLAN technology allows devices to

immediately connect to a LAN. As stated in

(Carmine Ciavarella & Fabio Paterno, 2003), to

locate the position of the users in a building, WLAN

is not a so simple solution, because the system has to

apply triangulation methods to the data coming from

at least three access points near the user. Installation

of many wireless access points will cause a negative

effect in a museum environment. In addition, the

developers have to devote a great deal of attention to

prevent ambiguous situations on the borders of the

intersections of the covered areas.

Bluetooth technology is an ad hoc technology

that requires no fixed infrastructure and is simple to

install and set up. A fundamental Bluetooth wireless

technology strength is the ability to simultaneously

handle both data and voice transmissions with low

power. It is designed to be small and to keep costs

low to be included in practically any device. Above

all, it has great ability to locate neighbour devices

and discover the type of services they could offer.

These properties make applications easier to use for

the end user, and also reduce maintenance costs,

characteristics which render Bluetooth suitable for

indoor environments.

IrDA protocol of communication supports high

data rates and requires line-of-sight contact. But

infrared has some drawbacks. Firstly, it rebounds

over the surfaces and secondly requires that sender

and receiver are aligned. IrDA is a point-to-point,

narrow angle (30° cone), ad-hoc data transmission

standard designed to operate over a distance of 0 to

1 meter. These limitations make IrDA not user-

friendly for e-guidance applications.

GSM LBS provide personalized services to the

subscriber based on their current position. But,

cellular positioning technologies are an opportunistic

development rather the original purpose of cellular

networks and consequently cellular technologies are

less accurate (J. Ranchordas & A. Lenanghan,

2003). Furthermore, GSM technologies add extra

cost to the end-user and discourage him from using

the application.

Finally, GPS is used from the majority of LBS

systems for outdoor tracking environments. The

position calculated by a GPS receiver requires the

current time, the position of the satellite and the

measured delay of the received signal. The position

accuracy is primarily dependent on the satellite

position and signal delay.

2.2 Localization Systems for Museum

Environments

Many localization and navigational based

mechanisms and frameworks are available in

museums nowadays, aiming to provide indoor and

outdoor LBS to end users. Their main disadvantages

are that they are tightly coupled to the localization

technology, user device, and content access

mechanisms and technologies. Thus, specialized

hardware and software capabilities are needed to

exploit them. Finally, human interaction is needed

most times not only to install them but also to

support them during their operation.

CMUseum provides location-aware video

streaming services with other add-on features which

enable automatic tour guidance without user

intervention. This design requires specialized

hardware, as it incorporates an 802.15.4 Zigbee

sensor network for collecting information as well as

an 802.11 Wi-Fi network for streaming video

contents. Yo-Ping Huang and Wei-Po Chuang

propose a pull-based approach guide system that

combines the positioning technique and location-

awareness service to provide the surrounding

information for users. The guide system not only

accepts the user’s search query to find the target but

also receives the information from other users who

took notes during the tour guide (Yo-Ping Huang

and Wei-Po, 2004).

Musex (Koji Yatani, Masanori Sugimoto &

Fusako Kusunoki, 2004) is also implemented to

LOCATION BASED GUIDANCE SERVICES IN A MUSEUM ENVIRONMENT: DEPLOYMENT ISSUES AND A

PROPOSED ARCHITECTURAL APPROACH

219

support children’s learning in a museum with use of

RFID for localization and a tour guide system which

is built for understanding how pervasive computing

can support a museum-like experience. The

Hippie/HIPS project (R. Oppermann & M. Specht,

2000) concerns the development of an exhibition

guide, which provides guidance and information

services. The guide senses infrared beacons installed

near all exhibits. From these observations about the

visitor’s journey through the exhibition the system

creates a user profile and suggests interesting

exhibits augmenting them with background

information. The limitation of this approach is that

often the user's position alone is not enough to

indicate interest in the closest work of art. Thus, the

risk is that the system erroneously identifies the user

interests and determines the corresponding user

model.

According to (Christian Kray & Jorg Baus,

2005), in terms of positioning, roughly half of the

systems rely on GPS while a large group of them use

infrared beacons. Furthermore, about half of the

systems include some means of interacting with the

user to determine his position. As far as the

architecture is concerned, some systems are based

on the client-server paradigm while others are built

using interactive applications. The first have the

advantage that, given a reliable connection between

client and server, they allow easy adoption of

multiple clients. The later offer a more decentralized

approach, but they may depend on a certain

device/platform.

In (Y. Wang & all, 2004), among others,

advanced wireless services are provided in the

International Airport based on GPS and WLAN

technologies, on a distributed, agent-based

architecture. Also, in (P. Kalliaras & all, 2004), an

ambient information system allowing GPS based,

location-aware, interactive guidance is presented. In

this system, a guidance session includes complex

content retrieval composed of geographical,

historical and geological information and can be

realized both on-site through handheld devices, and

through the Internet and TV channels. System

architecture is built based on the client-server

paradigm and Web technologies, with the focus

being on serving multiple communication channels

through a common content server. Based on the

experience acquired from the above frameworks, we

present a lightweight approach for providing

Location Based Content Retrieval in order to support

different e-Museum guidance services.

3 THE PROPOSED

ARCHITECTURAL APPROACH

FOR LOCATION-BASED

MUSEUM GUIDANCE

In this section a proposed architectural approach for

providing web-based location based multimedia

content retrieval through Java enabled devices is

presented. In order to avoid system lock-in and to

reduce development costs our approach is based on

open standards and open source components, where

possible. Furthermore, independence from the

underlying hardware and software, by selecting

generic widespread approaches, is provided.

The main advantage of the proposed approach, in

comparison with the implementations reported in

previous sections, is first of all, that the various

system components are designed and implemented

in a modular manner in order to select the most

appropriate in each specific installation. This

modularity regards:

• The separation of the positioning system from

the content access mechanisms.

• The selection of the localization radio

mechanism, accordingly with the

implementation site.

• The selection of the terminal mobile device. The

only requirement for the mobile device is to be

Java enabled, something very common in the

majority of the new generation mobile phones,

PDAs e.t.c. The content is being presented to

the device through any available web browser.

• Independence from the underlying hardware

infrastructure. The entire system is based on

Web technologies, which can be deployed

easily in any server.

• Independence from the content being available

to the end-user. All the content is available

through the content management server, and can

be renewed dynamically without any change

and any intervention to our system.

In addition, the entire process is transparent to

the user. In opposition with other LBS frameworks,

no input is requested from the end-user. He just

receives the appropriate content in his display, in

correspondence with his position. The system is

designed so that all the amount of data is transferred

through the local communication infrastructure.

3.1 Overall Architecture

In this section, we describe the core elements of the

proposed system architecture. The different

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220

components of our approach are the end-user

terminals, the backend platform components and the

communication infrastructure. The core elements of

the proposed system architecture and the way they

are connected are shown in Figure 2.

Figure 2: Core System Elements.

The main characteristics of these components are the

following:

• Localization technologies such as Bluetooth,

Infrared or GPS. These can be integrated to the

user device or provided as a separate hardware

module.

• The communication network, which can be any IP

enabled access network, e.g. a WLAN network,

GPRS or 3G network.

• The Terminal Module, that runs on the mobile

device. This is essentially a J2ME middlet which

implements the generic localization approach,

enables location tracking by using the terminal

localization device interfaces, and communicates

with the server-side component, which translates

physical location to content URI. It also provides

the appropriate Graphical User Interfaces.

• The localization server for providing association

between location information given by the user

terminal and a specific point of interest. The

association can be performed independently of the

localization mechanism selected - the content is

completely orthogonal to the localization

mechanism and can be renewed easily. This kind

of association is URI-based, because each point of

interest corresponds to a specific content URI in

the server.

• The content related to each point of interest which

becomes automatically available to the user

terminal by the content management system

(CMS), through the IP access network.

The redirection mechanism, which is based on

AJAX technologies (Jesse Garrett, 2005). As far as

the terminal-side is concerned it has to support

JavaScript. Otherwise, the redirection is

implemented through periodic HTTP refreshes to the

server-side.

3.2 System Components

3.2.1 Mobile Device Software – Terminal

Module

In order to search and select the desired point of

interest, we have developed a Java middlet that can

be installed easily in any mobile device that supports

Connected Limited Device Configuration - CLDC

and Mobile Information Device Profile - MIDP of

Java Platform Micro Edition - J2ME.

There is a configuration menu in the start form of

the middlet, where each user can select language,

audio and video options and complexity level for the

application. In case of indoor environments, the end-

user performs initially a search for localization

interest points -that exist within the scope of the

terminal- and the ID's of all the detected interest

points are returned. Otherwise, in case of tracking

technologies that are based on user coordinates (e.g.

GPS), the localization mechanism sends an exact

geographic coordinate instead of the ID. An extra

module is implemented in the server which converts

specific coordinates to unique IDs of points of

interest. All this information is transmitted through

the IP access network and is stored in the

localization database.

3.2.2 The Location to URI Database –

Localization Server

The database of the entire system is set-up on the

server. The database holds information about the

points of interest, the devices that executed the

application and information regarding the

association between them. Extra data are also saved,

correlating each point of interest with a URI, which

leads to the specific content for this point of interest.

Each time the Java middlet is started, the database is

updated with the new information sent from the

mobile device.

Every location corresponds to a URI at the CMS

server, as described earlier, – featuring some content

– static or dynamically generated. Almost

everything is controlled from the server, increasing a

lot the easiness of use for the end-user. Changes in

LOCATION BASED GUIDANCE SERVICES IN A MUSEUM ENVIRONMENT: DEPLOYMENT ISSUES AND A

PROPOSED ARCHITECTURAL APPROACH

221

the content don’t affect our application, rendering it

content independent.

We have defined various actors for different users in

our database scheme. The knowledge level and the

level of specialisation of every user are stored.

Different URIs are saved according to the native

language, the skills and the experience of the end-

users.

3.2.3 The Redirection Mechanism

After the initial installation of the middlet on the

end-users terminals, their browsers point to the web-

pages describing the corresponding nearest point of

interest. Ajax technology is used in order for the

terminals to remain active, waiting for the middlet to

update the database with the next point of interest.

As soon as the middlet inserts a new entry in the

database, new content is pushed to the browser by

the use of Ajax. The web-page is refreshed

asynchronously pointing to URI of the new point of

interest. In this way the web pages do not have to be

reloaded periodically. This is done only in case

where the terminal device does nοt support

JavaScript. The intent is to make web pages more

responsive by exchanging small amounts of data

with the server behind the scenes, so that the entire

web page does not have to be reloaded each time the

user requests a change. This is meant to increase the

web page's interactivity, speed, and usability.

3.3 Demonstration - Museum

Implementation

A museum e-guidance system application has been

developed in the scope of the E-Museum project

(*)

that utilizes Bluetooth localization technology for

the positioning of the museum exhibits and WLAN

technology for the IP network communication.

Content management functions are built based on an

existing CMS, as well as on e-museum specific

extensions. The open source Joomla CMS has been

selected. In addition, we have developed special

templates for mobile devices with the use of the Xe-

Media Mobile Template for Joomla. In each request,

the server checks the browser that makes the request

and accordingly returns the page in the appropriate

template.

As far as the implementation is concerned, we

chose to use a Nokia E61 smart phone with Symbian

OS, a 3COM 802.11g WLAN access point, 3

Bluetooth access points with power management

(class 1, 2 and 3) and a Linux HTTP and MySQL

Database Server. The development of this middlet

has been accomplished with Netbeans IDE 5.5

extended with the Mobility Pack for CLDC/MIDP,

while the simulations were implemented with Sun

Java Wireless Toolkit for CLDC 2.5.

The E-museum system overview is shown in Figure

Figure 3: E-museum System Overview.

Screenshots from the mobile device used are shown

in Figures 4 and 5.

Figure 4: E-museum Screenshot.

Figure 5: E-museum Screenshot.

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4 SERVICES OFFERED AND

OPERATION SCENARIO

In this section we describe the services that our

system offers to museum visitors. We support a wide

range of services targeted to the needs of different

user requirements. The most important of them are

the following:

1. Automatic (push) content retrieval based on

visitor proximity to an exhibit or group of

exhibits: The handheld device that the user

carries identifies his location in relation with a

certain exhibit or group of exhibits, through a

suitable positioning technology. After location

identification, a request for audiovisual content

related with a certain exhibit (or group of

exhibits) is created automatically.

2. On demand (pull) content retrieval: This service

is enabled via the E-Museum wireless

communication infrastructure and it addresses

more experienced users. Context aware

information, related with the user’s position, is

used to help him to browse the E-Museum’s

collections and/or to create more targeted search

queries.

3. Directional information (e.g. vector maps),

indicating the user’s current location in the

museum and how he can move throughout the

museum, can be offered to the user terminal

after request. The next desirable point of interest

can also be specified. In this occasion, a graphic

interface showing the most efficient route to

that spot is displayed instantaneously. In

addition, a traffic assistant can show the

snapshot of the current traffic flow in the

museum. This feature enables the visitor to

avoid big crowd in his tour.

4. Creation of live linear guidance: User provides

his profile and preferences (e.g. concerning a

certain historical period that wants to examine)

and the system automatically creates linear

guidance including only the exhibits of interest

and excluding exhibits that are not of interest to

the user. Guidance and location information is

also provided in this service.

5. Registration of path and content of interest for

offline usage: Users with handheld devices may

be able to get only a small subset of the content

while on-site, due to limitations in the

processing power of their devices. However, the

path with exhibits of interest is registered and

presentations with full versions of content are

created for offline usage (e.g. stored in CDs that

the user buys after the visit to the museum).

In the following section we describe the simple

steps that a user has to follow in order to access the

application.

1. The user downloads the middlet from the IP

network and installs it in his mobile device.

2. Then, his mobile device scans repeatedly, in a

defined time space, for points of interest

through the Bluetooth SDP.

3. Every time the middlet scans a new point of

interest, it communicates with the server and

informs it about the new data. The

communication is done via HTTP POST

messages.

4. The server holds information about the nearest

point of interest at which each user is every

moment and consequently sends to the terminal

device all the related content.

5. The user needs only to open a web browser to

his terminal device in a default page and,

through the redirection mechanism he will be

redirected to the page with the content of the

selected point of interest.

6. Each time a new localization trigger is received,

the user will be redirected to the content of the

new point of interest.

Special attention has to be given on the right

placement of the points of interest. In case of

redundant points that need to be identified within a

limited space, only one localization interface is

installed. The corresponding web page with this

interface is displayed on the user terminal display,

with multiple thumbnail images for the points of

interest, to allow the user to select the desired web

page. By this procedure, the offered application is

reliable in all cases.

All the above user steps are shown in Figure 6.

Figure 6: Operation Scenario.

LOCATION BASED GUIDANCE SERVICES IN A MUSEUM ENVIRONMENT: DEPLOYMENT ISSUES AND A

PROPOSED ARCHITECTURAL APPROACH

223

5 CONCLUSIONS & FURTHER

WORK

Based on the assumptions that it is desired to allow a

museum guidance system to dynamically select

localization technology, the appropriate software

and hardware for the backend platform, as well as

the terminal mobile device, we have argued that

comprehensive solution for museum location-based

guidance services should address the challenges of

modularity and openness. We therefore proposed an

approach for providing Location Based Guidance

Services that attempts to address these issues, while

we described an architectural framework for

enabling such

a system. The application of the

framework has been evaluated in a prototype e-

museum guidance system, highlighting some of the

issues involved in the use of location-based services.

Future work will include the support of user-

transparent handover process aiming at the selection

of the most suitable localization technique, in

heterogeneous environments (e.g. indoor-outdoor).

Experimental work is currently underway towards

evaluating the behaviour of the different localization

techniques in several, environments.

ACKNOWLEDGEMENTS

Parts of the work presented are funded by the

Semantix SA in the framework of the GSRT

PAVET-NE research and development action. The

authors of this paper would like to thank their

colleagues in Semantix S.A.

(http://www.semantix.gr) for their contribution and

cooperation.

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