The Landscape of Pervasive & Mobile Computing Standards Sumi Helal Synthesis Lectures on Mobile and Pervasive Computing Preface



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4.9 RICH MEDIA


The last trend involves rich-media content targeted specifically for the handset. As mobile operators are driven to differentiate and add value to their data services, they’re creating custom rich media specifically for the smart phone marketplace.

XHTML provides functionality for text, textual rendering, and basic graphics, but newer, more powerful standards to provide even richer content are becoming more popular. SVG (Scalable Vector Graphics), SMIL (Synchronized Multimedia Integration Language), ECMAScript, DOM (Document Object Model), PDF,4.3 Flash, X+V (XHTML + VoiceXML), and even digital television are becoming available on the mobile smart phone.

SVG, developed by the World Wide Web Consortium (W3C), is a markup format developed as a standard for describing vector graphics that’s becoming increasingly popular on mobile handsets using the SVG Tiny 1.2 Profile.3 X + V is another W3C technology that combines the voice interactivity of VoiceXML with the visual interactivity of XHTML.4.5

SMIL, although already deployed on millions of desktop clients, is showing its true value in the mobile domain.4.6 It describes the presentation layer and timing characteristics for an integrated multimedia presentation and is best known as the presentation layer for MMS (Multimedia Messaging Service) content as specified by the OMA. However, it can also render authored content specifically created for the mobile display. For example, ACCESS and KDDI, a major Japanese wireless operator, have jointly deployed a service that packages SMIL content into programs and pushes it to the handset during off-peak network times.4.7 Users can then view the SMIL program later, similar to an interactive television program. One popular program for this service is restaurant reviews that link video content to sample menus or a phone number for restaurant reservations. Other programs include interactive English lessons or fashion programs with links to additional details or purchase information.

There is also a strong trend to combine these individual technologies into extremely rich compound documents. The W3C has launched an activity to develop compound documents that combine one or more of these markups. Initial formats will combine XHTML and SVG, but later versions might also include SMIL, Voice XML, or other markups (see www.w3.org/2004/CDF).

ECMAScript and DOM—powerful scripting languages that are staples of desktop markup—are increasingly available on the mobile device.

With both powerful scripting and rich media now available, implementing true applications using the browser is becoming increasingly popular. This area will develop even further as the W3C’s Web application activity matures.4.8

4.10 THE BROWSER UI: DYNAMIC MENU TECHNOLOGY


The next logical step in this evolution is to extend the browser to become the UI container for the smart phone platform. Moving on from the rich media and application platform just described, by adding the ability to interact with the underlying smart phone hardware and file system, the Web browser can become the engine for the smart phone UI. This leverages the browser’s inherent capability to update content dynamically over the air—but instead of updating content, it updates the UI itself.

This technique also leverages the reliability, richness, and ease of authoring in developing the UI from traditional markup languages. As operators seek new applications to drive network usage and increase customization for the user, using the browser as the UI looks increasingly attractive.

There are three main methods for developing UIs for smart phones—using Java, XML-based implementation languages, or other markup languages (see the sidebar for more information). Our approach, dynamic-menu technology, uses a markup technique based on open Internet standards, to leverage the benefits associated with these standards.

4.10.1 Benefits


Open standards provide several advantages, including the availability of a wide array of development tools and a vast pool of experienced Web designers who can use their talents for UI design. With minimal modification, the same tools and development experience used to create standard Web pages are now available to develop complex UIs.

Additionally, using these Web technologies means that incredibly rich graphics, video, animation, and other media are now available for interface design. Because much of the required components and implementations already exist, implementation costs are low. Furthermore, because open standards are used to specify the UI behavior, suppliers can compete by offering lower prices.



COMPARISON WITH OTHER APPROACHES

The concept of a dynamically updatable, quickly implementable smart phone user interface is gaining traction in the cell phone industry. Three main methods exist for developing such UIs.

Java-based UI

Developers can write a UI for the handset completely in Java. Because Java is a powerful, fullfeatured programming language, developers can use it to achieve virtually any UI functionality. However, a modern handset’s Java Virtual Machine, while acceptable for gaming, doesn’t typically have the power of—or access to—low-level device functionality to provide a truly acceptable UI. Furthermore, a UI implemented in Java requires sophisticated programming skills, usually distinct from those of a graphical-content designer. Additionally, it’s a well-known problem that JSR (Java Specification Request) compliance varies widely among handsets, so each handset might require a unique implementation. Although Java for smart phones has been around for several years, use of Java-based applications outside of gaming has been disappointingly limited.



XML-based implementation languages

Another approach is to use an XML-based UI description language. XUL (an XML user interface language, www.xulplanet.com), used by Mozilla, is perhaps the most popular, but Macromedia’s Flex and Microsoft’s XAML (extensible application markup language) are other examples. These languages allow specification of powerful, sophisticated UIs. Perhaps owing to this complexity, few of these technologies have been implemented for a mobile device. Some implementation examples include Phoneomena’s xPhoneApp middleware (www.phoneomena.com) and Action Engine’s ActionEngine (www.actionengine.com). However, these technologies—especially XUL, which is based on open standards—seem promising for the future.



Markup languages

The next class of UIs is based on using markup languages targeted at graphical design. Examples of proprietary markup technologies are Macromedia Flash, Qualcomm Brew uiOne, and SurfKitchen. Macromedia Flash has a loyal community of designers familiar with the technology. Little public information for uiOne and SurfKitchen makes any analysis of these approaches difficult. The number of commercial options for providing a markup-based UI for smart phones reveals this strategy’s strength.

The last category is a markup technique based on open Internet standards. This is the approach our technology uses, because it leverages the benefits of open standards (see the main text).


In fact, using markup to build the UI means Web content effectively becomes indistinguishable from the menus and UI. Dynamic information such as current news headlines can be integrated directly into structures that have traditionally been part of the UI. Instead of a static idle screen, a phone dashboard can render all information vital to the user—such as news headlines, email alerts, or appointment reminders—in one central location.

Because the UI is now Web content, the same dynamic-update capabilities of Web content can apply to menu structures. The user can pull down to the handset an entirely new smart phone UI, treated just as another form of content, using the same functionality already built into the Web browser.

Using markup also allows rapid development and customization, benefiting several stakeholders in the value chain. For end users, this means customizing the device menu. Additional customization tools can be provided or a set of menu options or skins (customized UI graphics) can be built into the phone. So, users can directly customize the device or can do so on a desktop or network-located machine, later downloading the customizations. Users can customize menu functionality to make the applications that matter most easily accessible, and they can change graphics, themes, or skins to give the application a new look and feel.

For handset vendors, rapid development and customization make satisfying operator requests easier. Vendors must develop many handset models for different operators in a short product cycle, and each operator usually wants a slightly different menu configuration. Using dynamic-menu technology, the vendors can make different menu sets by simply updating the markup.

This means that wireless operators can better brand their service offerings. Most like to use a single UI across the spectrum of handset devices they offer. With the UI implemented in the browser, operators can use a single common markup to create a common UI across the complete spectrum of available devices. Or, they can create devices targeted for different customer segments—for example, they might target business users or young people with a custom UI. Such a flexible soft-UI approach is more cost-effective than developing a dedicated phone for each segment

Additionally, a dynamic menu means operators can create new types of service offerings. It’s easy to imagine a service that offers seasonally themed menus. Or, an operator might offer new value-added services for posting time-sensitive information such as news, weather, or stock quotes to the user’s root menu, where the information is most likely to be used. Finally, an operator might temporarily position new services or applications more prominently in the root menu interface to grab the user’s attention. These new service possibilities translate to enhanced functionality for the user and more revenue opportunities for the operator.

Finally, implementing dynamic-menu functionality requires only slightly additional handset memory. This is because the Web browser, which is virtually a required smart phone application, already implements most of the required complex rendering. So, implementation code size, a significant factor in handset architecture, is very efficient.


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