Web Access in Pervasive Environments- A Review

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Web Access in Pervasive Environments: A ReviewRoushdat Elaheebocus

School Of Electronics and Computer ScienceUniversity of Southampton, UK

[email protected]

Abstract. In recent years there have been considerable research work in the area of Web Access through mobile devices. In this

review paper, five important papers related to this area have been analysed. It has been uncovered that most solutions are proxy-based although hybrid versions exist. We also found that security and scalability aspects of the solutions have often been ignored andtherefore most of them are not practical in real-life scenarios.

Keywords: web access, pervasive, ubiquitous

Table of Contents

1 Introduction & A historical overview .........................................................................................2

2 Papers' Summary ........................................................................................................................2

2.1 Paper 1..................................................................................................................................2

2.2 Paper 2..................................................................................................................................2

2.3 Paper 3..................................................................................................................................2

2.4 Paper 4..................................................................................................................................2

2.5 Paper 5..................................................................................................................................3

3 Critical and comparative evaluation............................................................................................3

4 Conclusion...................................................................................................................................4

5 References....................................................................................................................................4

6 Bibliography................................................................................................................................5

7 Appendices ..................................................................................................................................5

7.1 Appendix A: Selection Process............................................................................................5

7.2 Appendix B. How this report influenced my ideas..............................................................67.3 Appendix C. Lessons learnt.................................................................................................6

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1 Introduction & A historical overview

With Mark Weiser's 1991's vision about technologies that are embedded into our everyday life whereby services can

be accessed anywhere and at any time [1], the foundation was set for ubiquitous computing environments. Around the

same period, T. Berners-Lee proposed a Hypertext project described as the World Wide Web [2] or the Web for short.

Roughly three years later, researchers started to come up with ways of accessing the Web using electronic devices overwireless networks and thus successfully bridging the above-mentioned two research areas. The incompatibility of

HTML with PDA displays were discussed along with the pros and cons of using such devices to access information

online [3].An application programming interface was even developed to help in the design and implementation of

applications for multi-device wireless networks [4]. Mobisaic [5] explored the idea of using contextual information

about mobile clients and how information can be adapted through the use of dynamic URL. In 1995, the Wireless World

Wide Web referred to as W4 was built [6] and became among the first web clients that could function over wireless

networks to access the Web. Digestor was an HTTP proxy that was published in 1997 and could transform pages

suitable for a specific device [7].However it could only be configured for one user at a time and was tested mainly using

PDAs. Dikaiakos [8] provided an overview of intermediaries which act as go-between for clients and servers. These

include notifications and wireless-web proxies that are important components for pervasive web access to this day.

2 Papers' Summary

We have chosen five recent research papers from the year 2000 to 2007 based on their relevancy with respect to web

access in pervasive environments while also taking into account their number of citations as an indicator about their

acceptability among researchers. We will now proceed with a summary of each paper in chronological order. More

details about the selection process is available in Appendix A.

2.1 Paper 1

In his paper entitled On proxy agents, mobility, and web access [9] in the year 2000, Anupam Joshi emphasised onthe fact that most solution that researchers were coming with at that time for mobile access to the web involved proxies.

He argued that proxy-based approaches are not always the best one specially for ad hoc networks where scalability can

become a problem. End-end techniques without intermediaries between clients and server can be more appropriate in

some of these situations. Therefore a hybrid approach was implemented involving a combination of both proxy-basedand end-end approaches.

2.2 Paper 2

Multibrowsing: Moving Web Content across Multiple Displays [10] by Brad Johanson et al suggested that themissing link in making ubiquitous computing as successful as the Web is the lack of a framework that can enable

browsing of information using multiple displays in both mobile and static environments. As a result, they proposed a

framework named multibrowsing that extends the information browsing metaphor of the Web across multipledisplays. This approach of tackling Web browsing is quite different from most others and therefore may be interesting

to consider.

2.3 Paper 3 Adaptive Interfaces for Ubiquitous Web Access [11] highlights the fact that browsing the Web from mobile devicescan become cumbersome and inefficient if no attempt is made at using adaptive personalisation technology to customise

the information according to the users' needs and devices' capabilities. Therefore the solution proposed was one that

could adapt itself based on users' preferences derived from a combination of similarity-based, collaborative and

Bayesian methods.

2.4 Paper 4

In A Web Browsing System based on Adaptive Presentation of Web Contents for Cellular Phones [12], a scaled-down image version of a web page requested by the client is provided. Known as the overview, it is divided into a

number of components which the user can select to zoom in and also read. Depending on the nature of the component

selected, the latter will be presented accordingly, for example, where images will be zoomed out to fit the screen and

can also provide auto-scrolling options users. The system was said to be effective but it was argued that due to lack of



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up scenarios as done in this paper. However it has been experimented with text-only mobile devices. Thus with the

latest high-resolution screen mobile phones and differing display size, this system will lead to under-usage of the

devices' capabilities specially since technologies keep improving almost exponentially.

Presenting a proxy-based solution, [12] the paper suggested that mobile phone screens are not wide enough toaccommodate whole web pages at one time thus making it difficult for users to navigate over different parts of the page

without losing the context. The solution proposed to this problem is by breaking webpages into different components

such as a list of links, tables of data and images and then allow users to view them individually by making a selectionfrom a reduced scale of the page. Although extracting components and classifying them are crucial for the whole system

to work, very little information is given about this step. However considerable experimentation was performed

involving sixteen test-subjects to check the auto-scrolling feature and how the users normally read each component

classes. While auto-scrolling can be an interesting feature for mobile phones with no button-only input capabilities,

there is a trend of phones equipped with touch-screens. Whether auto-scrolling will still be attractive in these situations

remains to be found out.

The proxy server software component responsible for the adaptation task is coded in C# and PHP which is a rather

unusual combination. But no justification is made about this choice nor about the phone used (SH900i model), equipped

with i-appli developed by NTT Docomo, and coded with Java.

According to the conclusion section, the solution still has problems in the classification of components task. This kind

of problem with become even more complex in the future since more hybrid and perhaps new classes of components

will be in use on web pages, leaving the efficiency of this system in uncertainty.

[13] also try to tackle the problem of small size display in mobile devices when browsing the Web. It adopts amodular design method when developing adaptation rules that are then used to generate strategies through an expert

system. This makes the system more maintainable and very extensible. Being a proxy-based solution, whenever a user

makes a request, the proxy, referred to as the adaptation server get the user's context which is then used to generate the

adaptation strategy that enables the selection of appropriate objects to make up the adapted content. These objects are

obtained by parsing the page requested by the user, decomposing it into components that are stored as a tree structure. A

number of scenarios have been tested and proven to work adequately with the solution.

Most of the papers analysed so far, are proxy-based and leaves the security aspects of these solution untouched.

However communicating through proxies can be vulnerable to man-in-the-middle attacks and thus unsafe for financial

transactions for example. Selective end-end communication as suggested in [9] can be an option in this case and in

addition to choosing only CPU-intensive or offline tasks, those requiring secure communications should also be end-end.

We must also highlight that with ubiquitous computing, it is expected that users are at the centre of the attention

instead of devices. Thus context awareness is crucial in the designing of systems attempting to solve ubiquitous

problems. While some papers take user-context as a factor in providing adapted contents, others simply take the only

the devices' capabilities into account.

Proxy-based solutions have been found not to scale up very well and can be a problem when devices are not aware

about its address for example. Some kind of broadcasting mechanism will have to be used to discover them, probably

the Web Service Dynamic Discovery (WS-D) [14] can be useful in this case.

4 Conclusion

We have seen that although many solutions are being proposed, we have yet to achieve a reasonably proven, security-

enabled, scalable and effective one for accessing the Web in ubiquitous and pervasive computing environment. Themain reason is probably because the Web is in continuous evolution and thus further research have to be carried out to

produce corresponding ubiquitous access methods. Nevertheless, we need solutions that can adapt to the constantly

mutating Web so that the relationship between ubiquitous computing environments and the Web can thrive, without

forgetting to bring the aspect of security on board.

5 References

1. Mark Weiser, The computer for the 21st century Scientific American (1991)

2. WorldWideWeb: Proposal for a HyperText Project, http://www.w3.org/Proposal.html. Accessed on 25

December 2008

3. Stefan Gessler and Andreas Kotulla, PDAs as Mobile WWW Browsers, Computer Networks and ISDN

Systems 28 (1994): 53--59, doi:10.1.1.48.9198.



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4. T. Watson, Application design for wireless computing, in Mobile Computing Systems and Applications,1994. Proceedings., Workshop on, 1994, 91-94.

5. G.M. Voelker and B.N. Bershad, Mobisaic: an information system for a mobile wireless computing

environment, in Mobile Computing Systems and Applications, 1994. Proceedings., Workshop on, 1994, 185-

190, doi:10.1109/MCSA.1994.513481.

6. J. F. Bartlett, Experience with a wireless world wide web client, inProceedings of the 40th IEEE Computer

Society International Conference (IEEE Computer Society, 1995), 154, http://portal.acm.org/citation.cfm?id=527213.793598.

7. Timothy W. Bickmore and Bill N. Schilit, Digestor: device-independent access to the World Wide Web,

Computer Networks and ISDN Systems 29, no. 8-13 (September 1997): 1075-1082, doi:10.1016/S0169-

7552(97)00026-3.

8. M. Dikaiakos, Intermediaries for the World-Wide Web: overview and classification, in Computers and

Communications, 2002. Proceedings. ISCC 2002. Seventh International Symposium on, 2002, 231-236.

9. Anupam Joshi, On proxy agents, mobility, and web access, Mobile Networks and Applications 5, no. 4

(December 1, 2000): 233-241, doi:10.1023/A:1019120915034.

10. Brad Johanson et al., Multibrowsing: Moving Web Content across Multiple Displays, in Ubicomp 2001:

Ubiquitous Computing, 2001, 346-353, http://dx.doi.org/10.1007/3-540-45427-6_29.

11. Daniel Billsus et al., Adaptive interfaces for ubiquitous web access, Commun. ACM45, no. 5 (2002): 34-38,

doi:10.1145/506218.506240.

12. Yuki Arase et al., A web browsing system based on adaptive presentation of web contents for cellular

phones, inProceedings of the 2006 international cross-disciplinary workshop on Web accessibility (W4A):Building the mobile web: rediscovering accessibility? (Edinburgh, U.K.: ACM, 2006), 86-89,

doi:10.1145/1133219.1133234

13. Stephen J. H. Yang and Norman W. Y. Shao, Enhancing pervasive Web accessibility with rule-based

adaptation strategy,Expert Syst. Appl. 32, no. 4 (2007): 1154-1167.

14. WS-Discovery Specificationhttp://specs.xmlsoap.org/ws/2005/04/discovery/ws-discovery.pdf. Accessed on

December 12, 2008

6 Bibliography

15. M. Satyanarayanan, Pervasive computing: vision and challenges,Personal Communications, IEEE [seealso IEEE Wireless Communications], vol. 8, 2001, pp. 10-17.

16. C. Patterson, R. Muntz, and C. Pancake, Challenges in location-aware computing,Pervasive Computing,IEEE, vol. 2, 2003, pp. 80-89.

17. K. El-Khatib, Z.E. Zhang, N. Hadibi, and G.V. Bochmann, Personal and service mobility in ubiquitous

computing environments, Wireless Communications and Mobile Computing, vol. 4, 2004, pp. 595-607.

7 Appendices

7.1 Appendix A: Selection Process

The original idea as about choosing a topic involving ubiquitous computing environments since this seems to be avery active research area and presents many challenges. Since this area is very vast, we have chosen to emphasise on

accessing services in ubiquitous environments and started a literature review by searching for papers related to these

terms in Google Scholar. Very soon it was found that in order to be able to explore an area better, more focussing is

needed rather that the broad area of service access in ubiquitous computing environments.

Since our field of study is Web Technology, it was thus decided to narrow our topic to Web Access in Pervasive

Environments. The next step was to find papers related to this specific topic by searching with keywords such as:

ubiquitous web access

http://specs.xmlsoap.org/ws/2005/04/discovery/ws-discovery.pdfhttp://specs.xmlsoap.org/ws/2005/04/discovery/ws-discovery.pdfhttp://specs.xmlsoap.org/ws/2005/04/discovery/ws-discovery.pdf


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pervasive web access

web access with mobile devices

web access in ad hoc networks

in Google Scholar, ACM and IEEE portals. This yielded hundreds of papers with the most relevant ones being in the

first 3 pages. From these results, based on the titles, the ones that seemed interesting were added to a new list.

Using the list, each of the items were followed up and the following criteria were taken into account to give each ofthem a score: relevancy of abstract to our topic and publication date. This effective weeded out most papers that had

misleading titles and those having been published more than 10 years before. Nevertheless, a few papers although out-

dated but which seem very relevant were kept to be used in the historical overview.

The items from the list were skim-read and interesting references were followed up. This brought a few other

interesting and relevant papers to our list which now consisted of 14 articles.

Since only five main articles are required, a more thorough selection process was performed involving additionalcriteria as detailed in the table below:

Blue colour means that the paper is among the best ones from our list. Orange ones are in the second level making them

interesting but less than the blue ones. Finally the yellow highlighted ones are from the least relevant or with less

acceptability among researchers.

This is how the five main papers were selected for this report.

7.2 Appendix B. How this report influenced my ideas

Before working on this report, whenever I heard about accessing the Web from other devices, specially smaller,

mobile ones, my idea was about creating other versions for each websites by the original web-designers themselves.Now I know that although this is a possible way, it is very impracticable. The options that are more convenient are those

that automate this conversion process, usually on-the-fly to adapt to a range of devices. Another approach can simply be

to suggest the user to move to a nearby public display unit to view a website in some cases. However, there is

considerable work to be done in the security area for these solutions and most papers have put security as a future work.

Since security is crucial when dealing with publicly accessible systems, if we want these solutions to succeed, security

should also be considered in parallel.

7.3 Appendix C. Lessons learnt

When attempting to solve a problem, even in research, the divide and conquer approach works best. That is, bigproblems should be broken into smaller ones and they become simpler to solve.

Number of citations is not always a good way of measure for a research paper in mainly two cases: Firstly when the



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research paper has been recently published and the second case is when a research paper tackles a problem area which

rarely looked at by other researchers. Also, a heavily cited paper in no way guarantees that it is a good one since the

references to it may be of negative nature. In this aspect, I would have liked to suggest that citation counts be broken

into 3 categories as detailed below:

+ Citations: for references praising a paper

~ Citations: for neutral references using definitions or explanations or methodology of a paper

- Citations: for references of negative nature highlighting the drawbacks of a paper for example

This will give a better idea to researchers when using citation count as a measure.

We also found that many research papers propose solutions that are not tested in real-life scenarios and therefore

cannot be relied upon when developing other solutions based on those.


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Web Access in Pervasive Environments- A Review