EFFICIENT INFORMATION RETRIEVAL FROM HANDHELD

TERMINALS WITH WIRELESS DIGITAL PHONE INTERFACE

Personalized information access on mobile phones and PDAs

Hans Weghorn

BA-University of Cooperative Education, Rotebühlplatz 41, Stuttgart, Germany

Keywords: Wireless information systems, Wireless data services, Personalization, Handheld HCI, Wireless JAVA

Abstract: Currently, the success of data services used through digital mobile phone networks is very limited. Different

reasons can be identified for this: At first, the costs for data connections through these wireless networks are

extremely high. Secondly, the user handling of the physically constrained handheld terminals appears as

very uncomfortable. Here, a concept for customer-centred information services is proposed, which meets

the limited capabilities of the terminal devices. An adequate UI is presumed to make the use of data services

on mobile digital phones as also on PDAs more convenient. Furthermore, the information access speed is

increased and the costs for the information retrieval are reduced by the described concept.

1 INTRODUCTION

Digital wireless telephony provides different meth-

ods for data communication. A very simple service

is the exchange of short messages (SMS) as connec-

tion-less datagrams, which carry as payload a small

text-based message. It is also possible to run con-

tinuous data links equivalent to a modem connection

for analogue landline phone networks. For the op-

eration of higher-level protocols, like WAP brows-

ing, there exist today different communication

methods, but the detail method is of minor interest,

when using this kind of service.

What appears more important and with direct

consequence to the user is how these data services

are handled, and which costs have to be paid for

their use. To the costs, it can be stated that these are

very high in comparison to landline telephony net-

works. On the other hand, for an access to the

worldwide Internet, private users have today mainly

the choice between landline and wireless telephony

networks. Most telephony companies operate both

kind of networks, and the tariffs of the different

companies are always in a very similar range, which

ends up with the actual situation that data transfer

costs through wireless links are much much more

expensive than through landline networks.

Considering next, the usability of data services

on handheld devices shows that the user has to deal

with some inconvenient limitations. Due to their

nature, the small devices are only equipped with

numeric keypads and small display screens. This, of

course, is required for keeping the units small,

lightweight, and preserving a long operation time

under battery supply. However, these inherent limi-

tations are often disregarded by the UI structure of

the terminal software: Tree-based UI systems requir-

ing in many cases lengthy input strings are more

than inappropriate for small devices. WAP browsing

is one typical negative example for this: The system

concept obviously was inherited from WEB brows-

ing on desktop computers with full keyboards and

huge screens, and by that, it appears not adequate for

the small devices (Johnson, 1998).

In a discussion of wireless data services, WLAN

as relatively new technology (IEEE standard 802.11,

1999) has to be regarded as well. For using WLAN,

either a Laptop computer or at least a PDA is re-

quired, which has the proper network interface

hardware. Although WLAN has established an im-

portant role in public life (Riezenman, 2002), and is

available in many public places – sometimes even as

cost-free service - it cannot fully substitute digital

links through wireless phone networks, because in

the WLAN system no roaming is foreseen. That

means if the user of the wireless data link starts

moving, the WLAN service is quickly lost. New

WLAN standards and concepts aim to implement

longer ranges and roaming features (Zahariadis, et

al., 2004), but in the end, much more complicate

hardware equipment is required than for the access

Weghorn H. (2004).

EFFICIENT INFORMATION RETRIEVAL FROM HANDHELD TERMINALS WITH WIRELESS DIGITAL PHONE INTERFACE - Personalized information

access on mobile phones and PDAs.

In Proceedings of the First International Conference on E-Business and Telecommunication Networks, pages 55-61

DOI: 10.5220/0001389500550061

 SciTePress

to digital phone networks. Hence, it does not make

sense to discuss WLAN at the moment as communi-

cation base for highly convenient wireless informa-

tion services, which should be seamlessly accessible

from any place.

Small mobile terminals like digital handheld

phones or PDAs with phone interface are equipped

with optimised properties in terms of movability and

operation stand-by time. For instance, a typical

phone can be linked to the phone network for up to

two weeks without recharging its battery, and it

weights only around 100 grams. On the other hand,

the constraints of the user interface demand a system

concept, which minimizes any required user input.

This can be met by the concept of customer-centred

service reported here.

In contradiction to general information services,

like e.g. WAP page sets, a service has to be operated

on the Internet side, which collects the information

particularly desired by a certain customer. The mo-

bile device shall play in this system only the role,

which was the original intention for these units: It

shall act as presentation terminal without much intel-

ligence. Like described with the examples in the

following sections there arise a series of advantages

from this concept: Optimised UI handling on the

terminal, reduction of data transfer volume, and by

that a cost reduction of the information retrieval and

an increase in information access speed.

Figure 1: On demand, a specific service agent sources the

desired information from the Internet and transmits the

result to the mobile terminal.

2 SOLUTION APPROACH

Due to the different inherent limitations of wireless

digital terminals, the following properties have to be

optimised for an information retrieval operated on

those units:

- Minimization of user input actions

- Minimization of data transfer in terms of vol-

ume and duration of the connection

- Minimization of computational efforts on the

terminal

A system concept, which fulfils these issues, can

be built up on a central service agent, which handles

and prepares the desired information contents on the

Internet side. In this concept, the mobile terminal

has to execute simple-styled display software

(Fig. 1).

2.1 Optimisation of the UI

A primary goal of the UI design is to minimize the

required user actions for obtaining information con-

tents on the mobile terminal. This can be achieved

with two closely linked applications: One applica-

tion is used for entering a configuration set for in-

formation queries. A second application is used for

executing the information retrieval. Technically such

a system can be implemented with wireless JAVA

(≡ J2ME ≡ JAVA micro edition) (Piroumian, 2002).

Main applications in J2ME are called MIDlets, and

MIDlets can be grouped in suites for sharing a non-

volatile data area – the so-called record management

store. Hence, this technology is well suited for im-

plementing exactly the proposed structure for the

terminal software (Fig. 2).

Figure 2: The terminal software can be constructed as

MIDlet suite containing two independent applications:

One for the information query, and another for configuring

the querying parameters.

The handling properties of the two application

parts are heavily asymmetric. While the actions for

running the querying part are minimized, the con-

figuration part may be as uncomfortable as used

from other mobile phone software tools. For config-

uring the runtime behaviour, specific data has to be

entered through the configuration tool. For instance,

ICETE 2004 - GLOBAL COMMUNICATION INFORMATION SYSTEMS AND SERVICES

if this system should be used for accessing e-mails,

all the relevant account information would have to

be entered; in this sample it would be an account

tering this will be very inconvenient, but the advan-

tage is that it will be performed very seldom. On

base of this input, the execution of the information

queries will be very efficient and easy to use, which

consequences that the user will see no barriers to use

the service very often.

2.2 The intermediate information

service agent

Next, the question shall be answered, how the query-

ing tool obtains the desired information content. A

data-mining agent residing on the Internet can be

employed for achieving this goal (Fig. 3).

JAVA offers again a convenient technical im-

plementation possibility with so-called Servlets

(Hall, and Parr, 2001). These are small software

tools, which can automatically be launched by que-

ries to appropriately configured WEB servers. Simi-

lar technical possibilities exist alternatively with

scripting programming languages like Perl or PHP,

but here the question is more important, which tasks

the mining agent has to fulfil.

On demand, the agent has to collect the desired

information contents from the open Internet, in most

cases this can come from various WEB sources. Of-

ten the same information is available on different

WEB sites, which are completely independent of

each other. If multi-sourcing of information is avail-

able, the central service agent can – in addition to

the plain data sourcing – qualify the accuracy of the

information. This quality of information – or with

recent terms this would be called more QoS = qual-

ity of (information) service – can be communicated

to the user. Especially the latter feature of the min-

ing agent shows that the concept is considerably

more elaborated than the idea for wrapper or media-

tors, which were reported earlier (Mahmoud, 2002;

Wang, 2003).

Hence, the central service agent will collect the

desired contents, and measure its precision, but it

will also finally prepare the obtained data for a

highly efficient wireless transfer. In contradiction to

the coding of WEB sites with (D)HTML (Zakour, et

al., 1997), or XML (Bradley, 1998), which do not

regard any size limits for content pages, the wireless

link should be operated with a minimal size for the

transferred information. This will help to speed up

the wireless transfer, and by that, it will help to

minimize the network usage cost. This communica-

tion structure respects that the bottleneck in such

system clearly is the wireless telephony link in terms

of transfer speed and tariffs.

Figure 3: An intermediate information-mining agent, which can be realized as JAVA Servlet, sources the desired content

from appropriate WEB sites on the Internet, and transfers the result to the handheld display terminal.

EFFICIENT INFORMATION RETRIEVAL FROM HANDHELD TERMINALS WITH WIRELESS DIGITAL PHONE

INTERFACE - Personalized information access on mobile phones and PDAs

2.3 Traffic information channel as

practical application sample

For showing the practical benefit of the described

concept, the following discussion should refer to an

information system, which is being implemented by

students of our University as exercise project. The

idea of the service is to provide a personalized ac-

cess to car traffic information. Most radio stations

operate today WEB sites (Fig. 4). These radio sta-

tions present in their on-air program information

about traffic jams, accidents, and recommended al-

ternative driving routes. Usually, the same informa-

tion is also accessible through the WEB sites, and

can be used for a service according to the before

described concept.

At the moment, two student teams are working in

our University independently on the realization of

systems, which retrieve traffic information from the

WEB by a central agent, and which allow a display

of this information through a specially developed

software on mobile (phone) terminals. In both traffic

information systems, the terminal software is im-

plemented in JAVA according to the concept in

Fig. 2. In the configuration tool the user has to enter

the highway or road name, for which traffic mes-

sages shall be retrieved. For regional traffic informa-

tion the QoS measure is being realized in these im-

plementations by sourcing WEB sites of different

independent radio stations, which provide this kind

of messages about the same region.

A traffic query can be initiated on the mobile

terminal with a minimum of user actions (Fig. 4):

The query application has to be selected from the

phone menu, and then it has to be launched. After

this, everything happens automatically: The query-

ing MIDlet reads the preferences from the configura-

tion data, and activates the agent on the Internet side

by a parameterised HTTP access (Knudsen, 2002).

For executing the central service agent, which is

realized as JAVA Servlet, a dedicate WEB server

host was installed at our University with the required

features. For this server a very short hostname was

chosen, and a shortcut to the WEB directory link

was configured, so that the services can be called by

a HTTP access with a very short target address.

Figure 4: Sample of a traffic information page of an Internet WEB site of a public radio station: This

source is used by the mining agent to collect the desired content - in the sample here the highway “A8” was

defined as querying target. After launching the display MIDlet on the wireless terminal, the agent is acti-

vated by a HTTP query (containing as parameter the selected road), and the returned result is displayed.

After this, the user can scroll through the response.

ICETE 2004 - GLOBAL COMMUNICATION INFORMATION SYSTEMS AND SERVICES

2.4 Realization of other information

systems

In the frame of an elaborated programming lecture at

our University the topic of J2ME was introduced

(Weghorn, 2003). The students could select as as-

sessment work one implementation project out of a

defined list of information systems, which are con-

structed like the one, which is described in detail

above. In total twenty teams of two students were

funded, and they were and they still are doing a de-

velopment of information systems on car traffic

channels, public transportation, railway connections,

and skiing arenas in the Alps.

The student teams are implementing both parts

of the information system – the terminal software,

and the central service agent. Of course, since this

work is part of a learning lesson, the results are not

all prefect. Only a few teams came close to the

above described optimal system concept. But in the

end, in sum a series of information systems are im-

plemented, which can be useful for various exem-

plary situations.

3 SIMULATION AND REAL

WORLD DEVICES

Due to budget limitations at our University, wireless

tools for digital phone networks cannot broadly be

developed and tested in the target environment. This

is also not really required, because simulation envi-

ronments are widely available for developing and

testing in particular J2ME applications. One simula-

tor is supplied within the wireless toolkit from the

company SUN Microsystems (accessible from

http://java.sun.org/j2me). If the developer aims for a

specific target device, all the big phone manufactur-

ers (Motorola, Nokia, Siemens, …) operate WEB

sites for developers, where simulators of various

JAVA-enabled phone models can be obtained. In

our practical experiments, simulation was used to

develop and officially assess the many different pro-

jects.

Some of the student teams ambitiously wanted to

run their tools on real physical devices and teleph-

ony networks. Hence, a few of the projects were

demonstrated in the real world. During this, it turned

out that the implementation of the J2ME idea is not

yet sufficiently elaborated on many devices. Even

when using the high-level UI only, the developer has

to take care of behaviours of mobile phone devices,

which were not in accordance to the original J2ME

specifications. Workarounds can be used in these

cases, but the problem that is shown by this experi-

ence is that at the moment it is not possible to rely

on a software, which is constructed in full accor-

dance to the J2ME specifications.

Without pointing to any specific vendor – be-

cause most phone vendors have similar styled prob-

lems – it has to be remarked that the level of the

average phone J2ME has not yet reached a profes-

sional state. Furthermore, security restrictions pre-

vent that the UI can be truly minimized, because in

many phones the user has to manually select the

applied network data link, when the JAVA MIDlet

starts an HTTP query. By this kind of mechanism,

for which there exist certainly good security argu-

ments, the terminal software cannot be optimised to

the full degree.

Another issue is the network access speed on real

world devices. The query for the traffic channel in-

formation takes on a real wireless phone network

approximately 15 seconds, while in the simulation

environment the query is processed in around a sec-

ond. Although this appears on a first glance as a

back draw, the use of the described service will be

much more efficient than the possible alternatives.

Considering the practical example that one has to

decide after breakfast which way to drive to the

working office, the information collection through

the proposed system would require at maximum half

a minute, and around three keypad presses ( user

input actions). The alternative would be to use a

voice announcement service, which would take at

least the same time, and the user has to select his

particular information out of this generalised service,

or to use WEB browsing on a desktop computer.

Especially the latter method would consume several

minutes for obtaining the desired decision input

(booting of the computer, connecting to the Internet,

browsing action, shutting computer down).

4 FUTURE TECHNOLOGIES

Starting the discussion of wireless data accesses with

the relatively simple SMS communication system

(section 1) probably does not appear as appropriate.

Nevertheless, due to recent developments in J2ME

technology, this ancient communication method will

come into question for the described information

systems. One important feature of the most recent

specification of wireless JAVA (it is named MIDP

version 2.0) is the capability of PUSH mechanisms

(Fig. 5).

With the PUSH system, J2ME tools can be acti-

vated automatically (Ortiz, 2003). For this, the

MIDlets have to register for the required service. In

the particular application here, the terminal display

EFFICIENT INFORMATION RETRIEVAL FROM HANDHELD TERMINALS WITH WIRELESS DIGITAL PHONE

INTERFACE - Personalized information access on mobile phones and PDAs

MIDlet can be activated by a SMS, which is sent

from the Internet agent of the information system to

the handheld device. Depending on the size of the

transferred content, the invoking SMS can already

carry the required information package, and no addi-

tional networking is required by the display MIDlet

for assembling its output.

This kind of communication can be used for,

e.g., the traffic information channel, because the

response to the mobile terminal typically is very

small: When the customer is on the way driving to

the working office or back home, a fully automated

system may be even more helpful than the above

described one, because the user will not be able to

actively handle information queries. With the PUSH

system the user can be informed automatically about

a recommend change of the driving route through

the combination of an information agent and the

appropriate terminal software. This variant would

truly reach the absolute minimum for required user

handling actions on the terminal.

Figure 5: The life cycle of a MIDlet of the most recent

J2ME generation provides with the PUSH system addi-

tional possibilities for activation.

5 CONCLUSIONS

In contradiction to generalised information services,

like e.g. WAP browsing, the proposed customer-

centred concept can make information access from

wireless handheld terminals very comfortable and

convenient. With this approach, the UI as also the

locally required computational effort can be mini-

mized. A lowering of costs and an increase of access

speed is presumed to make data services used

through wireless digital phone networks more attrac-

tive for the average, non-technical customer. How

this can be achieved, is shown with the sample im-

plementation of a customized traffic channel service.

The introduction of an intermediate information

agent allows also accounting for a topic, which is at

the moment widely disregarded: Most users are not

aware of the quality of all the huge amounts of in-

formation, which can be easily retrieved by WEB

browsing. The agent system allows measuring a QoS

value, which is also being implemented as example

in the developed traffic channel system.

As seen from the application of the proposed

tools in real world networks with real phones, there

is still space for optimisation. A further improve-

ment of access speed and UI comfort can only be

obtained, when the terminal developers, in particular

the phone manufacturers, improve the device soft-

ware. On the other hand, from the given examples it

can also be derived clearly that the handling of the

proposed service system is much more efficient than

traditional methods through voice announcement

services or WEB services accessed from desktop (or

laptop) computer systems.

Further concept developments and improvements

are planned with investigations on base of the newly

available PUSH technologies. The goal is to further

simplify the UI handling, increase the information

retrieval speed, and diminish the information access

costs.

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EFFICIENT INFORMATION RETRIEVAL FROM HANDHELD TERMINALS WITH WIRELESS DIGITAL PHONE

INTERFACE - Personalized information access on mobile phones and PDAs