Ch. Z. Patrikakis
National Technical University of Athens, Greece
P. Fafali
National Technical University of Athens, Greece
N. Minogiannis
National Technical University of Athens, Greece
N. Kourbelis
National Technical University of Athens, Greece
IntroductIon
Use of mobile devices for supporting our ev-eryday communication has become part of our daily routine. Recent statistics illustrate that the penetration of mobile devices in everyday use has reached (and in some cases even surpassed) the penetration of fixed communication devices (ITU, 2004). As a consequence, use of mobile devices for accessing data information also increases, assisted by the rapid development of new technologies especially designed to support multimedia communication. Within the next
years, third-generation (3G) wireless services will proliferate, offering multimedia capabilities such as streaming video (BERGINSIGHT, 2005;
Raghu, Ramesh, & Whinston, 2002; UMTS forum, 2005). All of these, combined with the establishment of Internet and portal technology as the standard way for information exchange, entertainment, and communication, have created a new scenery that is characterized by access to data “anywhere,” “anytime,” and by “anyone”
(or “any means”). Design issues concerning the particularities of access devices, communica-tion technologies, and volume of informacommunica-tion
exchanged are very important in the provision of mobile portal services (Microsoft, 2006).
In this article, we address the issue of provid-ing portal services to users with portable devices such as personal digital assistants (PDAs) or smartphones. We propose a reference architecture for providing mobile portal services, based on the distribution of information between the portal servers and the user devices.
Background
The need for mobile portal services lies in the penetration of mobile devices in the global market.
However, the services offered today are not widely adopted by the mobile users. Surveys that have been carried out have revealed that cost, both in terms of devices (such as PDAs) and operation/
subscriptions, constitutes a prohibitive factor.
Furthermore, complexity has been mentioned as another reason for avoiding such services. Many people have also expressed their interest in more personalized content tailored to their profile, or in having the ability to create their favourites and set their preferences. In addition, users consider access speed as a key factor, meaning that they prefer minimum-step navigation, since they are not willing to spend much time and money to reach the information. Last, but not least, the applica-tions that offer mobile services are not offered by the mobile operators or are not preinstalled in the devices, but are sold by third-party vendors.
Consequently, many people are not aware of available mobile services.
Despite the aforementioned impediments to the explosion of Web services offered to mobile users, mobile-enabled information and market will define the near future scenery. Besides, this story bears similarity to how mobile phones pierced the whole world. The transition from generic Web portals to mobile portals should not be only associated with the adaptation of the content to the display size of the mobile devices.
Mobile services should meet the varying needs of a “moving” user. A mobile user may need im-mediate access to crucial information, or may be in the process of waiting in a queue or for his flight to take off. Furthermore, mobile portals should focus on supporting concrete services for different target groups.
An attempt to organize mobile portal services into categories, according to global practice (GSA, 2002), leads us to the following categorisation:
• Information Services: General news, weather forecasts, financial, and sport news.
• Food and Lifestyle: Restaurants, bars, music halls, theater, cinema, events list.
• Travel Services: Flight/hotel listings, travel guides, maps, position location, and direc-tion guidance.
• Entertainment: Online games, horo-scopes, and quizzes.
• Mobile Commerce (M-Commerce): With real estate, Web banking, shopping, and auctions.
• Messaging: MMS, SMS, Chat, e-mail ser-vices.
• Personal Information Management: Cal-endars, contacts, photo albums.
The end-user experience is enhanced by the improved interfaces, use of graphics, touch pads, and technologies, such as VGA screens and cam-eras built into the devices (Mobile Tech Review, 2005). Many mobile portals have been launched combining information from the previously men-tioned categories (GSA, 2002).
requIrements
The basic idea behind the reference architec-ture proposed in this article is to overcome the limitations imposed by the handheld devices capabilities (display size, battery) and the cost of
network connectivity into a platform that provides ubiquitous access to a large portfolio of services.
Initially, we define the requirements set for the system design.
user Friendly Interface for users unacquainted with computers
Up to now, use of mobile and portable devices in our everyday life for communicating and enter-taining ourselves has been a common practice.
However, the concept of accessing information through PDAs instead of desktop PCs is quite new and, therefore, special care should be given to the design of applications services and the corresponding user interfaces.
As opposed to the case of voice communication and music entertainment, where the functional-ity of the device is limited to simple dialling or play-forward-rewind-stop, handling information presents several challenges. The user has to select the information that he needs to access, and then decide whether the result of his/her selection meets his/her demand. Furthermore, links between dif-ferent types of information have to be specially designed in order to facilitate navigation. The small screens of mobile devices introduce an extra challenge: the “shrinking” of data so that the same level of information fits to much less than a quarter of minimum display of an average desktop computer.
coherent site map to minimize navigation and Facilitate users’
experience while reducing network connectivity costs
This is actually a requirement for any portal design. However, PDA terminals have special characteristics, that make minimization of navi-gation steps and connectivity costs very crucial.
These characteristics are the low processing power and memory of portable devices, as well as the limitations in network connectivity that is
provided over GPRS. Therefore, reaching infor-mation with minimum interaction is a key point for successful design of Web pages.
up-to-date content
Ubiquitous access to information places an extra effort for portal designers. If we take into account the nature of information that is expected to be requested from a mobile device (news, weather updates, financial information), then it is obvi-ous that the majority of user requests will be for dynamic content, constantly updated. Therefore, the designers and administrators of mobile por-tals should focus on data update and back-office mechanisms.
User Notification and Push content mechanisms
One major difference between “conventional”
portals and mobile portals is the inability of these devices to maintain permanent connections to the portal. Therefore, for example, in a mobile portal that provides information about the stock market, updates on the price of stocks could be provided to desktop users through long last sessions (even for hours). This is not possible in mobile devices, not only due to the nature of the underlying communication infrastructure (GPRS-UMTS), but also due to the fact that deployment of other applications on the device (a phone call) may interrupt the session. Furthermore, the use of the mobile device is not the same as that of a desktop computer that is confined in a certain position on a desk.
For this, special mechanisms for notifica-tions about data updates, and also push content mechanisms should be provided for information that is constantly changing, and this change has to be immediately reported to the user. The case of Blackberry devices (Research In Motion, 2006) and remote management capabilities in Windows mobile 5.0 (Microsoft, 2006) are excellent ex-amples of such mechanisms.
ProPosed archItecture
On the ground of the requirements set, users should have fast response and online feedback on crucial information. An ideal way to achieve both demands is to take advantage of the memory space of the handheld device, and to discriminate content into static and dynamic. The notion is to have locally stored information that need not to be frequently updated, such as travel guides, maps, restaurants’ and bars’ addresses or description.
This kind of data can be preinstalled in the device and can be renewed periodically through a syn-chronization process, depending on the type of information (i.e., tourist-related information may be updated yearly, while entertainment-related information should be updated more often). The dynamic content can be obtained through direct connection to the mobile portal.
Special provision should be given so that the information provided through the portal is in a form that can be used off-line. This is very crucial for cases where this information regards promotional offers, addresses in terms of phone and fax numbers, and location information. In this way, the user has access to a wide range of services without needing to be always connected to the portal. Especially in cases where use of the mobile device is expected to happen in areas with poor network coverage (i.e., mountain resorts where access to GPRS is not always available), the previous requirement becomes essential.
Another important issue is that of subscription to active information-sources (such as newsfeeds or stock-market) results in periodically updated reports that can be sent by SMS to end-users. Also, users belonging to a specific group (i.e., group of tourists) can be informed by announcements for special events organized. Photos taken dur-ing holidays can be uploaded in personal folders hosted under the portal, and can be used for send-ing e-cards or for creatsend-ing a photo-album.
There are many issues regarding the frequency with which content should be updated. First of all,
most of the online information is provided in the form of RSS-feeds (Loutchko & Birnkraut, 2005), which are information feeds offered by specific content providers. Therefore, there is no burden for the mobile portal administration to update information such as weather forecast, headline news, and so forth. Moreover, weather reports can provide “safe” forecast for a short future period (e.g., for 5 days) so that a user does not have to be connected to the mobile portal on a daily basis. In order to simplify the process of adding offers or dynamic information for the companies that are hosted and promoted by the portal, online tools can be provided for the renewal of the commercial information.
A proposed architecture for an end-to-end implementation of a platform that satisfies these requirements is depicted in Figure 1.
The platform consists of the following com-ponents.
Web server
This constitutes the core component of the ar-chitecture. The server is linked to the database server for accessing portal information, while it incorporates interfaces to both end-user devices (PDAs—smartphones) and content providers. For interfacing the end-user equipment, both push and pull technologies are deployed. Thus, it supports access to information over GPRS, UMTS, WLAN, and SMS. Though “pull mode” for content access is easy to understand (as this is the standard way to access information through html), “push mode” is especially applicable in the case of mobile devices.
This is offered mainly through the use of SMS for sending information, such as announcements, confirmations, and notifications, without the user having to request it.
Regarding the interface towards the content providers, this is used mainly for the upload of information to the mobile portal. This is achieved through various methods (RSS feeds, XML files, e-mail, and file upload). Information is
ing from the Web server. As a variation of the architecture at this point, the Web server may be substituted by two components: a Web server that is used solely for hosting the Web pages and acting as the front end of the platform, and an application server that is used for providing the rest of functionality (i.e., access for the content provision mechanism). If we take into account the case of SMS, then a third component (SMS gateway) needs also to be inserted in the platform description. Figure 2 describes the detail break-down of the Web server into three specialized components:
• Web server (front end);
• Application server (for back office access);
• andSMS gateway (offering SMS interface to the system).
database server
The database server is used to store:
• all the information that is accessed through the Web server; and
• data regarding the devices that have access rights to the information.
For this, apart from the communication to-wards the Web server, it also incorporates an interface towards the access and device manage-ment server, so that the later can control access to the available content and enforce subscription policies. Regarding the interface towards the Web server, this is provided for two reasons:
• for presenting the information to the end user through Web pages (statically or dy-namically formed); and
PDAs
Smartphones RSS feeds
mail FTP uploads XML
information exchange
Dynamic content (offered through )
Static content (linked to dynamic content)
Connection through GPRS/UMTS/WLAN/SMS
Pull content Push content
Access and device management server Database server
Web server
Web pages
Figure 1. Proposed platform implementation
• for providing access to the content provision mechanisms (through the aforementioned interfaces, deploying either only the Web server as the interfacing point or, alterna-tively, an application server).
access and device management server
This component may be optional, in the case where access to the mobile portal is provided without any restriction. However, since access to the informa-tion may be offered as a commercial service, this component is necessary to ensure that this access is granted only to registered users. Towards this
end, both pull and push mechanisms for content access through the users’ devices are being con-trolled by the access and device management server. Information regarding registered devices and/or users is provided from the database server.
An important issue that the access and device management server is called to address is that of activation-deactivation of applications. As it has been mentioned, part of the information is stored to the mobile devices. In the case of a commercial service that is based on subscriptions, access to the information stored on the devices needs to be enabled and disabled, according to the payments status of the user. The access and device manage-ment server has to ensure that.
Figure 2. Proposed platform implementation
RSS feeds
mail FTP uploads XML
information exchange
Database server
SMS interface
SMS gateway
Application server
Web interface
Access and device management server Web server
end-user devices
These are the devices that are used for accessing the mobile portal, and are described as PDAs or smartphones with Web-browsing capabilities.
Based on the hardware and firmware capabilities of the devices, we may distinguish two different ways to present Web services to the users:
1. The devices are running a fat client appli-cation that is responsible for presenting a comprehensive interface to the user. In this case, the handheld device or mobile phone runs an application (written in a program-ming language such as Java or C#) that is responsible for supporting the first level of access to information. By this application, the user has the ability to access information stored to his/her device directly, without the need of connecting to the Web portal. Such information, of course, is of the static type, while in the case where updates or access to information that is dynamic (i.e., weather forecasts) is needed, the application connects to the Web portal, accesses this information, and presents it to the user through a native application interface. The advantage of this approach is that the user can be offered comprehensive functionality, surpassing the capabilities of simple Web-based services, while push content mechanisms can be eas-ily implemented, transparently, to the user.
However, a drawback of this approach is that it requires the use of sophisticated devices with operating system capabilities, as those of Pocket PCs, while activation and deactiva-tion of the applicadeactiva-tion needs to incorporate a special mechanism (i.e., expiration of licences, SMS, or Web-enabled activation mechanism) while it is vulnerable to cracks and hacks.
2. The devices incorporate a thin client applica-tion, such as that of a Web browser. In this case, all the functionality is transferred to
the Web server. Of course, in order to reduce the level of interaction, static information is again stored and accessed locally on the user’s device, while all dynamic information is located again on the server. The drawback here is that the functionality that is offered to the user is reduced to that supported through the mobile portal Web pages, while in general, push content mechanisms cannot be deployed. On the other hand, management of the information is easier, while access control is simplified (it only requires access control to the Web server).
Further Issues
This architecture presents a general approach to the issue of information access through portable, mobile and handheld devices. However, provision of an application or service needs to take into ac-count the particularities of each case, which may introduce differentiations even at architectural level. This will be clear through the example of an application for tourists.
Such an application, apart from the standard functionality for access to information (both static such as hotels, restaurants, museums, and dynamic, such as festivals, theatres), requires extra functionality such as:
• Translation of Content to Different Lan-guages: Though this is easy for the static content, in the case of dynamic content that is produced on a daily basis, automatic trans-lation mechanisms need to be incorporated in the system.
• Location-Based Service Offering: Loca-tion awareness is crucial here. This can be provided through the use of GPS hardware or through location-based services from mobile operators. Correlation of the user’s location to the content of the mobile portal is the key point for offering value-added services.
• Support through a Call Center: In the case where the service is provided through a “hot line” for assistance to the users, a special mechanism for giving access to the call center empowering this hot line is nec-essary. This means that the corresponding interfaces and mechanism for data access, customized to the needs of the operators of the call center, needs to be designed and inserted in the architecture.
conclusIon
As we see, there is no panacea for the provision of mobile portals. The diversity of user needs, together with the flexibility offered by the ubiq-uitous computing capabilities of smartphones and PDAs, make each case special. However, the core of requirements, as this is identified in the previous sections of this article, is the first issue that needs to be addressed when designing such services.
Fertile ground for the provision of services through mobile portal access is provided in the areas of:
• Mobile portals at the service of smart home concept (remote monitoring, remote appli-ance access);
• Mobile portals at the service of smart home concept (remote monitoring, remote appli-ance access);