A MULTIMEDIA-BASED GUIDANCE SYSTEM FOR VARIOUS

CONSUMER DEVICES

M. Kropfberger, R. Tusch, M. Jakab, J. Köpke, M. Ofner

M3-Systems Research Lab, Department of Information Technology, University Klagenfurt, Austria

∗

H. Hellwagner, L. Böszörmenyi

Department of Information Technology, University Klagenfurt, Austria

Keywords:

Multimedia-based guide for stationary and mobile devices, context-awareness, content adaptation, presenta-

tion adaptation, content management.

Abstract:

This paper introduces a Web-based guidance system which offers optimized presentations of sights or exhib-

ited objects on different types of available stationary and mobile consumer devices, possibly running different

operating systems. This is accomplished by adapting both the objects’ content and their presentation to the

current usage context. Content thereby may be encoded in different presentation formats like video, audio,

image, and marked-up text. The usage context embraces a set of properties describing the current usage envi-

ronment of the guide. This includes, for example, the consumer device’s capabilities, its current location, and

the user’s preferences. Both, the content adaptation and presentation services are based on standard Web tech-

nologies for increased interoperability. Finally, the guidance system is augmented with a Web-based content

management and a statistics module, which enable for remote content administration and usage evaluations,

respectively.

1 INTRODUCTION

With the emergence of affordable hand-held con-

sumer devices, offering adequate screen resolutions

and enough CPU power for reasonable video decod-

ing, multimedia services are no more limited to pow-

erful stationary devices. Many of these services are

becoming feasible to such mobile devices. Due to the

mobility factor and battery operating times of over

three hours, such a service may be a multimedia-

enriched mobile guide, which, for example, could be

used for exhibitions or touristy regions. Thereby, the

guidance may be supported by context-sensitive us-

age information which is obtained in advance and/or

dynamically during the guiding process.

This paper introduces a Web-based guidance sys-

tem, called M3-Guide in the sequel, which supports

optimized presentations of exhibited objects or places

∗

This work was partially supported by the Austrian

Science Fund (FWF) under project L92-N13 (CAMUS:

Context-Aware Multimedia Services), and by the austrian

network for e-tourism (anet) under project Tourguide für

Web und mobile Endgeräte.

of interest on different available stationary and mo-

bile consumer devices. It does this by adapting both

the objects’ content, as well as their presentation to

the current usage context. Content thereby may be

coded in different presentation formats like video, au-

dio, image, and marked-up text. The usage context

embraces a set of properties describing the current us-

age environment of the guide, including user proﬁle,

device proﬁle, network proﬁle, location, and time.

2 RELATED WORK

Context awareness has become a major issue in mo-

bile computing recently. Especially for mobile de-

vices with limited device capabilities (like screen res-

olution, network bandwidth, and computing power),

content and its presentation often need to be tailored

to meet these limitations. This is essentially required

for multimedia presentations which are mostly en-

coded for high screen resolutions with high bit rates.

A number of research contributions address adap-

tation methods and techniques for content and pre-

Kropfberger M., Tusch R., Jakab M., Köpke J., Ofner M., Hellwagner H. and Böszörmenyi L. (2007).

A MULTIMEDIA-BASED GUIDANCE SYSTEM FOR VARIOUS CONSUMER DEVICES.

In Proceedings of the Third International Conference on Web Information Systems and Technologies - Web Interfaces and Applications, pages 83-90

DOI: 10.5220/0001281100830090

 SciTePress

sentation adaptation. For example, adaptation ser-

vices for multimedia content are addressed by the

QBIX intelligent media proxy (Schojer et al., 2003;

Kropfberger and Hellwagner, 2005), the Princess

platform for multimedia service adaptation (Korva

et al., 2001), the Negotiation and Adaptation Core

(NAC) architecture (Lemlouma and Layada, 2004),

the MM4U framework for personalized multime-

dia content (Scherp and Boll, 2005), and especially

within the scope of MPEG-21 Digital Item Adapta-

tion (Bormans and Hill, 2002; Vetro et al., 2006; Dev-

illers et al., 2005; Vetro and Timmerer, 2005; Tim-

merer and Hellwagner, 2005). Web-based presenta-

tion adaptation relying on various markup languages

like HTML, XHTML and SMIL is a quite mature

research topic, extensively addressed in the area of

adaptive hypermedia systems (Brusilovsky, 1996; Bra

and Calvi, 1998; Bulterman et al., 2005; Lemlouma

and Layada, 2003).

All adaptation methods have in common that they

take into account context information in their adapta-

tion steps. The context describes the usage environ-

ment of the application and spans a number of dimen-

sions. These include the user’s proﬁle (e.g., language,

age class, interests), the device’s proﬁle (e.g., screen

resolution, decoding capabilities), the network’s pro-

ﬁle (e.g., available bit rate, delay), and the location

and time of content consumption. Context informa-

tion may be partially described by the Universal Pro-

ﬁling Schema (Lemlouma and Layada, 2004), which

is based on CC/PP and RDF (Klyne et al., 2004),

by UAProf descriptors for device capability descrip-

tions (Open Mobile Alliance, 2006), and by MPEG-

21 Usage Environment Description tools of MPEG-

21’s Part 7 Digital Item Adaptation (Bormans and

Hill, 2002).

There are already guidance systems for hand-held

mobile devices which take into account some dimen-

sions of usage context. Two examples of such guides

are the Cyberguide (Abowd et al., 1997) and the Mo-

biDENK (Krösche et al., 2004) guide. However, they

cover only the two dimensions user proﬁle and loca-

tion, but they do not take into account device and net-

work capabilities, and hence they do not adapt content

and presentations dynamically to different networked

and non-networked stationary and mobile consumer

devices.

3 GENERAL OVERVIEW

Figure 1 provides a general overview of the M3-

Guide. On the left-hand side it is shown that con-

tent of various types (video, audio, text, image) for

objects of interest can be fed into the system via a

Web-based and hereby platform-independent content

management system (CMS). Content may be stored

in different languages, and associated with predeﬁned

special user proﬁles like age class, historical insterest,

technical interest, and many more. The Web-based

CMS is accessible from everywhere, and the content

may be managed in parallel by different responsible

persons.

Once fed into the system, the content is then

adapted and presented according to the current usage

context. This includes the location, which is either au-

tomatically determined by different technologies like

GPS and Bluetooth (Santner et al., 2006), or manu-

ally captured by entering the number of the current

object of interest. The M3-Guide also adheres to the

user proﬁle containing information about her/his age

class, preferred language, and interests. And ﬁnally,

content may be presented depending on the current

time. Thus, messages like “dear visitor, the park is

closing in a few minutes” are displayed right on time.

One major focus of the M3-Guide is the large vari-

ety of networked or disconnected consumer devices.

Networked devices may be wireless mobile phones

using UMTS, and WLAN-connected Pocket PCs, lap-

tops and Tablet PCs. Stationary devices may be strate-

gically positioned info terminals, private Web PCs, or

video walls. All networked devices receive all content

directly from our system, which optimizes it to the

current usage context. This is illustrated by the cen-

tralized adaptation module. Video and audio streams

are adapted to ﬁt to locally available codecs and CPU-

bearable frame and bit rates. Images are resized and

texts are prepared to ﬁt the screens and available

fonts. Further, the whole HTML-based browser appli-

cation including navigation, search forms, and icons

is adapted to match the devices’ capabilities.

Since these devices are usually connected, the

content is up-to-date and content changes in the CMS

are immediately forwarded to the presenting devices.

On the other hand, the CMS is also capable of produc-

ing so called “local dumps” for disconnected devices.

Such dumps can be later stored on memory cards

for mobile phones and Pocket PCs, and on DVDs

for desktop PCs and data terminals running in kiosk

mode. A local dump can also be created for printable

media, where a list of all objects of interest with print-

able content is prepared to allow folder and booklet

creation.

Finally, a statistics module logs complete user

sessions and allows periodical statistics on, e.g., fa-

vorite/average content consumption, most used lan-

guages and proﬁles, average duration of sessions, and

WEBIST 2007 - International Conference on Web Information Systems and Technologies

Figure 1: The big picture of the multimedia-based guidance system.

stopover times at certain objects of interest. In a net-

worked scenario, the statistics are enhanced by real-

time information about e.g. the number of active ses-

sions, and the current locations of the users. This

knowledge can easily be fed back into the adaptation

system to offer improved content and presentation op-

timizations, and to give suggestions to the users.

4 REFERENCE APPLICATION

MULTIMUNDUS

The M3-Guide is designed having easy customiza-

tion to different application areas like museums, fairs,

theme parks, touristy regions, or even shopping cen-

ters in mind. As a ﬁrst evaluation, our system was

successfully introduced to Minimundus (Minimundus

GmbH, 2006), an outdoor theme park in Klagenfurt,

in June 2005.

Minimundus presents over 140 different 1:25-

scale replicas of world-famous buildings like the Eif-

fel Tower, or the Sydney Opera House. In allusion

to "multimedia for Minimundus" we named the guid-

ance application MultiMundus. In MultiMundus, all

140 exhibited objects are covered, and each object

offers at least informative text stories and still im-

ages. 42 of them are enriched with audio and/or video

stories, where a narrator gives in-detail information

about these objects. All texts, audio, and video sto-

ries are available in four languages (German, English,

Italian, and French). For deaf people, audio stories

are also available as videos in Austrian sign language

for these 42 objects.

The park is covered by a WLAN network, such

that rentable or private mobile devices can reach the

main server. Ten rentable devices (see Figure 2) are

available for a small fee. The devices are Linux-based

HP iPAQs 5550 with a ruggedized cover, headphones,

a hand strap, and an input pen on a string.

The Minimundus team has access to the Web-

based content management system and can easily

manage the objects and their content. Live statistics

about the current usage of the devices are also avail-

able, and periodically summarized statistics may be

sent via email. Finally, Minimundus also offers DVDs

with local content dumps in addition to the printed

catalogues, such that visitors are able to enjoy the

MultiMundus presentation even on their private PCs.

A MULTIMEDIA-BASED GUIDANCE SYSTEM FOR VARIOUS CONSUMER DEVICES

Figure 2: The rentable M3-Guide with screen shots.

5 SYSTEM MODULES AND

TECHNICAL BACKGROUND

5.1 Content Management System

The Web-based content management system (CMS)

is designed for easy administration, and hence it is

optimized for content administrators. First, it allows

the insertion, editing, and deletion of proﬁles (like age

class and historical interest). With the chosen object-

oriented approach, it is possible to use inheritance and

late binding between proﬁles. For example, there may

be an adult proﬁle, which inherits all objects and con-

tent to an inheriting proﬁle, such as historical. It is

possible to override content from inherited objects. In

that case, a video for the adult proﬁle would be re-

placed by a historically enhanced version. Of course,

it is also possible to retain the video of the adult pro-

ﬁle and to add an extra history video into the historical

proﬁle.

Second, the CMS enables for the insertion, edit-

ing, and deletion of object content with the follow-

ing subtasks: editing the neighborhood, uploading

videos, uploading audios, uploading images for the

photo gallery module, and a built-in WYSIWYG edi-

tor for marked-up text content.

And third, built-in scripts automatically generate

special info texts based on metadata. Consequently,

each object has a standard text content showing the

year of construction and the country of origin with a

graphical ﬂag.

For consistency reasons, the CMS works on a lo-

cal copy of the repository when updating content.

Therefore, it is possible to propagate changes when

they are submitted, or to propagate them at a speciﬁc

time when load on the live system is reduced (e.g.,

at night). For extendability reasons, the CMS is fully

implemented in object-oriented PHP scripts.

5.2 Content Repository with Xml

Metadata

The M3-Guide’s repository is ﬁle-based (see Figure

3), hence it is easy to synchronize, to partially backup,

and to update via shell scripts. It follows a simple

structure, whereas each proﬁle is represented by a

folder, with all objects being subfolders. In these ob-

ject folders, an info.xml ﬁle stores the object’s title and

other metadata about the object in all supported lan-

guages. In the MASTER folder, the different content

types (audio, images, movies, and stories) are man-

aged. These subfolders hold either direct language

versions for a single content, or – like in the stories

folder – each story has its language version folders

with an index.html there.

Figure 3: The content repository structure.

Besides the MASTER folder, each known de-

vice proﬁle creates a subfolder with a cache of its

transcoded and adapted content on demand. As a

result, there are different video versions in differ-

ent resolutions and encodings for different platforms,

WEBIST 2007 - International Conference on Web Information Systems and Technologies

such as Flash video for Windows-based Web PCs and

MPEG-4 video for Symbian-based smartphones.

5.3 Transcoding Multimedia Cache

Since the M3-Guide supports video and audio play-

back on many different consumer devices like Win-

dows Mobile-based Pocket PCs, Linux-based PDAs,

smartphones, and standard Web PCs, the content has

to be transcoded and adapted to the consumer de-

vices’ capabilities. Since the content is mainly static,

the transcoded content is also subject to caching.

Moreover, many hand-held consumer devices are con-

nected via expensive networks (as e.g., UMTS) on the

one hand, and may be equipped with cheap memory

cards on the other hand. Thus, a live-streaming of

adapted content over expensive networks is not eco-

nomic. Therefore, adapted content should be pre-

cached on local memory cards.

As a consequence, the M3-Guide uses a multi-

level transcoding and caching architecture, where

one or more master Transcoding Multimedia Caches

(TMCs) run on the network and have direct access

to the content repository via HTTP. On the consumer

devices, a client media cache is implemented, which

uses the local memory card as cache storage.

One of the master TMCs performs the transcod-

ing step and, at the same time, stores the results in

its server-side cache. Furthermore, it streams the

transcoded data to the requesting consumer device,

which in turn caches the adapted content locally. Con-

sequently, later requests can be fulﬁlled from the local

cache, and the master system and network is not used

unnecessarily.

The TMC is written in platform-independent Perl

and runs on Windows, Linux, and Windows Mobile-

based platforms. Each TMC uses plugins for the

known transcoding formats and caching behavior, de-

pending on the underlying platform. Currently, com-

bining all platforms, the following containers and

codecs are supported: avi, wmv9, 3gp, ﬂv, swf, mpg,

mp4, theora, mp3, ogg.

In principle, the requests to the TMC are HTTP

URLs, and the device-speciﬁc parameters are coded

into these URLs. If, for example, the real media

was accessible from a Web server via http://media-

example.com/video.avi (see Figure 4), a M3-Guide

PDA would request this as a Windows Media video

in 320× 240 pixels via

http://localhost/cgi-bin/media.cgi?u=

http://media-example.com/video.

avi&c=wmv&w=320&h=240

If the local Client Media Cache has no cached ver-

sion stored, it will forward the request to the master

Figure 4: Schematic view of multiple transcoding multime-

dia caches.

TMC1 with the following URL:

http://tmc1.com/cgi-bin/media.cgi?u=

http://media-example.com/video.

avi&c=wmv&w=320&h=240

The master TMC1 may fulﬁll the request from its

local cache, it may need to transcode the source of

the video on its own, or it may ask another TMC2 for

transcoding, if no suitable plugin is available.

5.4 Statistics Module

The statistics module manages the collected usage

data and offers different views on it. When the mobile

consumer devices have a permanent network connec-

tion, real-time statistics like the actual usage and the

currently viewed object of a certain device are avail-

able.

Furthermore, ofﬂine interval statistics are calcu-

lated on a daily, weekly, or monthly basis and cover

two groups of interests:

• data concerning the business: the number of

visitors who used the system; cache capacity

bottlenecks of rented devices; average device

rental time; which objects/contents are frequently,

which ones are rarely consumed; user demograph-

ics (language, age)

• technical data, in order to improve the system it-

self: device management like maximum battery

usage time, battery recharge time, and irregular

wear; click analysis of menu structures and navi-

gation

The system performs a separation of information

extraction queries, which are executed on the col-

lected data, and of reports which prepare a busi-

ness ready view for the management. These reports

A MULTIMEDIA-BASED GUIDANCE SYSTEM FOR VARIOUS CONSUMER DEVICES

use textual and graphical output and are delivered as

comma separated ASCII values (.csv), HTML, Latex,

and PDF output. The reports are stored in an archive

and sent to the responsible persons via email.

It is easy to dynamically integrate new queries

and reports without the necessity of difﬁcult system

changes, and all queries and reports are dynamically

parameterizable (e.g., it is easy to adjust the time in-

tervals of reports).

Technically, the statistics module is implemented

in PHP, initiated with cron jobs, and uses phplot for

graphics creation.

5.5 Server Details

The M3-Guide server system uses Apache, PHP5.0,

and MySQL to handle client connections, to process

the repository, and to adapt the content to the current

usage context.

The software is modularly written, so each content

type like audio, video, image and story is handled by

a special module, which itself is triggered by the re-

quest URL from the ﬁle-based repository.

When a content module claims responsibility for

a certain content, it prepares a temporary XML repre-

sentation of the application screen (e.g. the thumbnail

view for images, or the text story), where also the con-

tent’s metadata (like the title in the current language)

is extracted from the corresponding info.xml. This

XML output is then processed by an XSLT, which

transforms the XML into a device-speciﬁc HTML

code for optimized presentation. This HTML code

is cached and transmitted to the connected consumer

device.

The MySQL database keeps track of currently

connected sessions and their usage contexts. Thus,

it also knows about the speciﬁcs of certain hardware

device proﬁle settings such as screen resolution or de-

codable video formats.

Finally, the M3-Guide offers a special exporter,

which crawls through the repository and prepares a

device-speciﬁc HTML representation of all available

proﬁles and objects including their contents. These

local dumps are enhanced by device-speciﬁc appli-

cations like an auto starter or a self-extracting Web

browser. These dumps can be distributed on SD-

Cards and DVDs, which may be used on private

Pocket and Home PCs, respectively.

5.6 Supported Mobile Devices

5.6.1 Pocket Pcs with Windows Mobile

For Windows Mobile-based Pocket PCs we have de-

veloped a C#/.net application, which offers a full-

screen object presentation by the use of a Pocket In-

ternet Explorer widget and custom video player. All

hardware buttons are reprogrammed and we offer a

library to access the built-in WLAN, GPS, and Blue-

tooth. The HTML content is delivered either locally

from an SD-Card or via WLAN. Additionally, a local

media cache (see Section 5.3) delivers all videos from

the local SD-Card or via WLAN. The navigation ei-

ther works manually via the Quick Navigation (by en-

tering object numbers), or automatically via GPS and

Bluetooth, if applicable (Santner et al., 2006).

The Windows Mobile-based guidance application

can be stored onto an SD-Card, as it is the case for

videos and all other content. After plugging the SD-

Card into a Pocket PC, the M3-Guide application is

started by the operating system automatically.

5.6.2 Pocket Pcs with Linux

For the reference application MultiMundus, we used

Linux-based HP iPAQs 5550 with Familiar Linux, a

well-patched Dillo Web browser, and our own video

player based on our self-developed multimedia library

ViTooKi (Kropfberger and Schojer, 2003). The boot

process was modiﬁed in a way that the system al-

ways boots into full-screen mode, without a window

manager, and without any functionality of hardware

buttons. Due to performance reasons, the rentable

devices use a memory card for the local caching of

videos. Thus, the WLAN is not bothered too much

with parallel video streaming. All presentation data

and not yet cached videos are retrieved via WLAN

from the server.

5.6.3 Smartphones with Symbian Os

We have ported the M3-Guide to Symbian 8.0s Series

60 2nd Edition, shipped on an RS-MMC dual voltage

memory card. Since the system is completely HTTP-

based, it is easy to connect via UMTS and hereby

spare the local MMC card. This may offer more up-

to-date information, but will lead to high telephone

costs.

Our software launches an Opera Web browser and

then behaves like a Web server, which offers the lo-

cal MultiMundus content. When a video is requested,

our own full-screen video player is started. Videos are

stored as 3gpp containers including MPEG-4 video

and AAC audio streams. The video is resized to

WEBIST 2007 - International Conference on Web Information Systems and Technologies

176x208 pixels and transcoded to the correct codecs

by our automatic server-side adaptation process. See

the two Nokia 6630 smartphones in Figure 1. The

navigation is realized by manually entering object

numbers and is handled with a HTTP-CGI applica-

tion.

Another useful feature is the server-side interpre-

tation of specially formed HTML links which de-

scribe telephone numbers. After clicking such a link,

the Symbian smartphone starts to dial the number.

This enables for a personalized booking of certain ser-

vices.

5.6.4 Further Devices

The M3-Guide was successfully tested with various

WLAN-enabled devices such as the Nokia N770 In-

ternet Tablet or the Sony Playstation Portable. After

connecting to the Multimundus WLAN, it was pos-

sible to request the HTML start page via the built in

Web browsers. Video and audio were played back via

built-in players. Of course, the presentation did not

perfectly ﬁt the screen resolutions and other device

capabilities like optimized video codecs, but at least

it was usable out of the box.

5.6.5 Supported Usage Scenarios

Table 1 gives an overview of all supported platforms

and devices, and classiﬁes the support based on three

possible usage scenarios.

Table 1: Supported platforms and devices.

Device proﬁle network

/ un-

touched

network /

prepared

local /

prepared

iPAQ h5550 with Em-

bedded Linux

X X

Pocket PC with Win-

dows Mobile

X X X

Smartphone with

Symbian OS

X X

Nokia 770, Playsta-

tion Portable

WebPC / Infoterminal

/ DVD

X X X

The ﬁrst column depicts the ideal scenario, where

a private (untouched) device may access our M3-

Guide system via a conﬁgured network without any

software installation process. We support this for

Windows Mobile-based devices, private Web PCs,

and to some extent (see previous subsection) for the

Nokia 770 and the Sony Playstation Portable.

The two other columns discuss well-prepared de-

vices, where optimized video players are installed and

a custom application is presented in a fullscreen kiosk

mode. The content is either retrieved via a network,

or from a local storage subsystem. In order to reduce

future network load, some devices use a hybrid ap-

proach where content is cached on a local storage sub-

system.

6 USAGE ACCEPTANCE AND

FACED PROBLEMS

The M3-Guide’s reference application MultiMundus

(see section 4) was introduced to Minumundus Kla-

genfurt in June 2005, and was available there to visi-

tors during the whole remaining operating year 2005

(about four months until the end of October). This

time period was used to evaluate the user acceptance

and performance behaviour of the guidance system,

and to consequently improve the system based on the

obtained evaluation results.

Summarizing the usage evaluation results, such

a location-aware and multimedia-enriched guidance

system is rather a high-end solution for some inter-

ested visitors, who want to consume more informa-

tion than provided by commonly available catalogues

and brochures. For example, in the most frequent

month August, 123 out of about 40.000 visitors rented

the MultiMundus guide, resulting in a rental percent-

age of only 0, 31%. Since there were ten mobile

guides available for rent, and each device was rentable

about three times each day (due to usage and battery

recharging times), the actual rentals also reached only

13, 23% of 930 possible rentals. Thus, two rentable

mobile devices would have been enough on average.

The reasons for these low rental rates are man-

ifold. First, Minimundus did not offer the Multi-

Mundus guides directly at the cash. Instead, the place

of disbursement was separated to the main entry in the

park. Second, Minimundus also offered "old" audio

guides in parallel to our MultiMundus guide. Some

people just wanted to passively listen to spoken text,

rather than to actively read or watch videos. Third, the

MultiMundus guide was more difﬁcult to explain than

it was the case with the audio guides, although the

visitors found that the usability of the MultiMundus

guide was good. As a consequence, the staff respon-

sible for handing out these devices got more and more

lazy with explaining the MultiMundus guide’s usage,

and preferred to hand out the old audio guides. And ﬁ-

nally, the mobile guides were encapsulated in rugged

cases to prevent them from damages on occasional

drops and rains. The rugged cases made the guide

considerably larger and more unhandy to wear.

Beside the low rental rate problem, there were two

A MULTIMEDIA-BASED GUIDANCE SYSTEM FOR VARIOUS CONSUMER DEVICES

more crucial problems related to the used mobile de-

vices. First, the battery life cycles where partially re-

ally short. Many of the used batteries were dead at the

end of the season. And second, the staff who handed

out the devices has occasionally broken some of the

power connectors, when plugging them into the slide-

on receptacles. Sometimes, even the hardware reset

buttons were pushed through and hence those devices

had to be repaired.

CONCLUSION A Web-based and multimedia-

enriched guidance system has been introduced that

customizes both content and its presentation to the

current usage context. Content may include differ-

ent coding and presentation formats like video, audio,

image, and marked-up text, and can be managed by

the means of a Web-based content management sys-

tem. Presentations are based on standard HTML doc-

uments for images and texts, and on custom and com-

monly pre-installed video players for video and au-

dio streams. The usage context plays a central role in

the whole adaptation process. It spans a number of

different dimensions, including the user proﬁle, the

consumer device capabilities, the network capabili-

ties, the location, and the time of content consump-

tion.

The presented guidance system was introduced

and evaluated in a local outdoor theme park in 2005,

and was available to visitors of this park over the

whole operating year. Statistical evaluations have

shown that such a multimedia-enriched guide is rather

a high-end solution for some visitors, who want to

consume more content than provided by commonly

available catalogues.

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