This talk describes basic architectures and best practices for implementing Software as a Service applications. In this context, achieving good margins requires making careful engineering trade-offs between adding features and lowering total cost of ownership. Achieving good system utilization requires that businesses share resources using either virtual machines (OS-level virtualization) or multi-tenancy (application-level virtualization). While multi-tenancy achieves greater levels of consolidation, it limits the kinds of features that can be provided. Thus the ideal level for virtualization depends on the characteristics of the application and its users.

Failures in properly identifying requirements are perhaps the major cause of the software industry's poor record of delivering working software systems on-time and to budget. Requirements engineering is the branch of software engineering concerned with identifying the real-world goals for, functions of, and constraints on software systems.
This talk reflects on some current issues in requirements engineering for enterprise systems, including capturing government regulations (an increasingly-important source of business requirements), using precise modelling languages in the requirements engineering process, and the role of "anti-requirements" in software assurance.

The talk depicts the evolution of enterprise architectures to their today often used service-oriented form and presents as state-of-the-art development process Quasar Enterprise for this kind of architecture.
The development process covers both the development of a business architecture as well as of an appropriate software architecture. While showing up a possible form of further evolution of enterprise architectures, we identify the major challenges for future development methods for enterprise architectures.

The talk and demonstrations will illustrate a rigorous approach to the engineering of services for service-oriented architectures and in particular, web service compositions. We use formal model checking techniques to cover aspects of architecture, orchestration, choreography and deployment configurations for service compositions. A demonstration will illustrate our techniques using an Eclipse based tool, known as WS- Engineer. WS-Engineer is based upon the Labelled Transition System Analyser (LTSA) and provides mechanisms to assist engineers in developing and analyzing service compositions. The tool has also been adopted as part of academic courses in the teaching aspects of a services science. The talk is based on work in London Software Systems a grouping that includes academics at Imperial College London (the speaker, Jeff Magee, Jeff Kramer and Sebastian Uchitel) and at University College London (Wolfgang Emmerich, Anthony Finkelstein and David Rosenblum)

Enterprise distributed computing has made rapid strides in many sectors of the economy, such as telecommunications and finance sectors. Organizations are now reaping benefits of these advances through better efficiency and better quality of services worldwide. There have been attempts by many groups to implement such benefits in the healthcare sector, the largest business sector in the world. However, this sector presents some unique challenges that have to be overcome if enterprise computing has to succeed in this sector. This talk will present an overview of emerging trends and future challenges in this field based the presenter's experience in the areas on integrated service management and e-Health through the leadership of a number of global initiatives, such as the WHO eHealth for Healthcare Delivery (eHCD) involving six countries, ITU-D Mobile e-Health initiative (m-Health) for Developing countries involving 20 countries and the International ubiquitous Healthcare initiative (u-Health) that led to the formation of a chain of research centres called Asia-Pacific u-Health research Centre (APuHC) in Australia, Singapore, Taiwan, South Korea and India. People involved in these initiatives meet at IEEE Healthcom (founded by this presenter) every year (see www.healthcom2008.org).