Chapter 17. The Luther Architecture: A Case Study in Mobile Applications Using J2EE

with Tanya Bass, James Beck, Kelly Dolan, Cuiwei Li, Andreas Löhr, Richard Martin, William Ross, Tobias Weishäupl, and Gregory Zelesnik

Note: All of this chapter's contributors work for Inmedius Corporation in Pittsburgh.

God is in the details.

?Ludwig Mies van der Rohe

Workers involved in the maintenance or operation of large vehicles (such as tanks and aircraft) or portions of the industrial infrastructure (such as bridges and oil rigs) have great difficulty using computers to support their tasks. Because the object being maintained or operated is large, work on it must be in situ, outdoors or in special structures, neither of which is conducive to desktop computing. In particular, a computer solution usually involves a wireless infrastructure and either a handheld or a hands-free computing device.

Inmedius is a company that was established in 1995 as an outgrowth of Carnegie Mellon University's Wearable Project (see the sidebar History of Wearable Computing) to provide support for front-line maintenance and operation workers. Initially producing one-of-a-kind solutions for its customers, as the company grew it realized the necessity for general solutions that could be quickly tailored to a customer's needs.

The front-line worker does not work alone but requires a great deal of back-office support. Problem reports must be collected and work must be scheduled to enable repairs to be made, replacement parts must be taken from inventory and re-ordered, and maintenance records must be analyzed. All of this work-flow management requires integrating the front-line worker with the back-office worker who has access to a desktop computer.

The Luther architecture was designed to provide a general framework within which Inmedius could provide customized solutions for the maintenance problems of its customers. It is based on the Java 2 Enterprise Edition (J2EE) architecture, so becomes an application of the general J2EE/EJB framework (discussed in Chapter 16) to an environment where the end user is connected over a wireless network and has a device with limited input/output capabilities, limited computational capabilities, or both.

History of Wearable Computing

Arguably, the first wearable computer was the wristwatch. It was invented around 1900 and at first was unable to compete with the pocket watch. Why would someone wear a watch on his wrist when his existing pocket watch kept good time and could be accessed quite freely? However, during World War I, the British Army issued wristwatches to its troops so that they could synchronize attacks while keeping their hands free for weapons. Suddenly, it became fashionable in Britain to show support for the "boys in the trenches" by wearing wristwatches. Now, of course, you rarely see a pocket watch.

By the early 1990s, technology had begun to support the wearing of digital, full-function computing devices. One organization investigating the use of these devices was the Wearable Group of Carnegie Mellon University headed by Dan Siewiorek. They viewed a wearable computer as a tool to support workplace functions, with the workplace epitomized by locales where aircraft and other large vehicles were maintained?out of doors or within large buildings such as hangars or railroad roundhouses.

The focus on use in a workplace meant that ease of use and design sophistication were primary. The Wearable group conducted experiments with computers designed and constructed by students in actual workplaces. The success of these experiments created the demand that Inmedius was organized to exploit.

A second group, operating at the same time and centered at the Media Laboratory of the Massachusetts Institute of Technology, styled themselves "borgs." They viewed the wearable computer as a consumer product designed to change the lives of those who wore it. They wore their computers all of the time and were interested in innovative uses of them and in memory support applications. One example was using the conductivity of the skin as a network medium and having two computers exchange business cards when their wearers shook hands.

By the late 1990s, the two groups were collaborating to make wearable computers a viable academic discipline. Various commercial companies had begun to offer computers and head-mounted displays, and large commercial concerns had begun to show interest. Now, with the increasing miniaturization of hardware and the increasing sophistication of software (as evidenced by this chapter), wearable computing can only become more prevalent.


    Part Two: Creating an Architecture
    Part Four: Moving From One System to Many