From Composing Services to Composing Gadgets


Google Tech Talks
January 17, 2007


This presentation discusses HUSKY, a new spreadsheet environment for service composition and design and USCA, a tree-tiered distributed architecture for service composition execution. The synergy of the Web and gadgets (e.g. Google Gadgets, Mac or Yahoo Widgets) presents an opportunity to evolve the way we conduct our day-to-day interaction with resources on the Internet. To expand the Web from pages to processes, end users are provided a simple and intuitive way of composing gadgets into personalized Web processes. We choose service composition as the underlying technology for gadget composition. To enable efficient gadget composition, we propose a new methodology and architecture for service composition.

HUSKY, a human-centered service composition workspace and methodology, is an end-user environment extending the classical spreadsheet into a tool for composing services into a personalized process flow. It is the first service composition system designed with the spreadsheet as a primary medium, pioneering an effort to weave Internet services with a broadly understood and intuitive paradigm that has proven it’s advantages and popularity over the decades. We extended the spreadsheet by adding a sequence or time dimension, while keeping in focus a tight structure to retain simplicity and a grip on consistency. This spreadsheet design enables intuitive expression of concurrency and non determinism of service composition through a visual arrangement of service activities within spreadsheet cells.

Efficient execution of service compositions is the motivation for expanding the widely known two-tier coordination architecture into a three-tier service composition architecture called USCA (Uncoupled Service Composition Architecture) architecture. We use it within HUSKY to schedule services onto separate machines, enabling more flexibility in the distribution of functional elements to host machines of a distributed system. The result, both the performance and scalability of distributed applications are improved using a USCA architecture making it the underlying choice for executing widgets composed using Husky.

Presented by: Prof. Sinisa Srbljic, Ph.D., University of Zagreb

Sinisa Srbljic is a Professor at the University of Zagreb (the oldest and largest university in South-Eastern Europe), School of Electrical Engineering and Computing. He received his B.S. degree in electrical engineering in 1981, and M.S. and Ph.D. degrees in computer engineering in 1985 and 1990 respectively, all from the University of Zagreb, Croatia. He was visiting the University of Toronto, Canada, from 1993 to 1995 where he worked on the NUMAchine multiprocessor project. As a visiting scientist from 1995 to 1996, he was working with the Advanced Technology Group of AT&T, USA, on caching of Internet objects in large distributed multimedia systems. During summers 1997, 1998, and during fall 1999, he was visiting AT&T Labs, Internet Platform Organization in San Jose, California, where he continued his research on the design of a large scale distributed Internet information system. During summer 2000, he was visiting the University of California, Irvine, Department of Information and Computer Science. Prof. Srbljic holds several US patents on scalable systems and network object caching. He can be reached at:

Sinisa Srbljic
University of Zagreb
School of Electrical Engineering and Computing
Unska 3, 10 000 ZAGREB,
Croatia, Europe

This Google Tech Talk was hosted by Boris Debic.
google, howto, composing, services, gadgets


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