Hanan Lutfiyya

Context-aware service selection based on dynamic and static service attributes

Context-aware applications are able to use context, which refers to information about the surrounding environment, to provide relevant information and/or services to the user. A context-aware application may need to make use of existing services (e.g., a print service). There may be several possible choices of services. The context-aware application should be able to discover and select a service that considers context (e.g., current user location). Existing architectures and protocols for service discovery, however, are not suitable for doing so. Contextual information, by its very nature, is dynamic, reflecting the current state and conditions of the application, its user, or its operating environment. Existing architectures and protocols for service discovery, however, tend to assume the world is static, with attributes describing services offered never changing. If attributes are allowed to change, the approaches do not provide the architectural mechanisms required to update them; dynamic attributes with no means of updating are static for all intents and purposes. To support context-aware service discovery and selection, a better approach is required. This paper discusses one possible approach that is based on existing techniques.

Issues in Managing Soft QoS Requirements in Distributed Systems Using a Policy-Based Framework

We address the problem of Quality of Service (QoS) requirements for multimedia applications (e.g., distance education, telemedicine, electronic commerce). These applications need to be able to co-exist with more traditional applications for transaction and data processing and have soft real-time requirements. Unlike most other work in QoS management, we provide a framework that does not require users or application developers to have detailed knowledge of the resources needed and resource scheduling and allocation techniques in use. These underlying details are effectively hidden. In this paper, we describe our strategy, an architecture of services to support the strategy and a prototype.

Providing a differentiated quality of service in a World Wide Web server

This paper presents a strategy of extending a Web server to be able to differentiate between requests in different classes. This is required because most Web servers are unable to do this by themselves. We present our strategy and its design along with some initial performance results.

Herecast:an open infrastructure for locationbased services using WiFi

This paper describes a location positioning system called Herecast. Herecast addresses many of the current weaknesses found in current location positioning systems. This paper describes the Herecast architecture and how it has been used to develop several location-aware applications

An extended operational profile model

Operational profiles are a quantification of usage patterns for a software application. These profiles are used to measure software reliability by testing the software in a manner that represents actual use. The current definition of an operational profile states that it is the set of operations available in the application, and the operations probabilities of occurrence in customer usage scenarios. This definition is too limited. In most industrial applications, focusing on operations alone does not offer adequate representation of the use of software. The limited definition of operational profiles can restrict their applicability and hence software reliability analysis for many software development organizations. This paper describes a formal and practical extension of the current definition of operational profiles to increase their applicability.

Using the vista 350 telephone to communicate the results of home monitoring of diabetes mellitus to a central database and to provide feedback

PURPOSE Self-monitoring of blood glucose has become routine practice in the management of diabetes mellitus. When all the data is complete, however, the amount of information to be taken into account when making therapeutic decisions becomes overwhelming not only for the patient but for the healthcare provider. Computers excel at processing large amounts of information quickly and impassively, which makes them potentially helpful for collating and communicating the data in a manner that facilitates decision-making by patient and healthcare provider. This should in turn improve control and help prevent acute and chronic complications. METHOD Using the Vista 350 telephone, we have developed a system that enables patients with diabetes to record home monitoring data to a central database and receive feedback summaries. A small trial was conducted to determine if the Vista 350 telephone is an acceptable and feasible method to communicate the results of home monitoring of diabetes mellitus to a central database and receive feedback summaries. A total of 35 volunteers with insulin-requiring diabetes mellitus in the London area were randomly allocated to either use the Vista 350 phone for 6 months, or to a control group that continued to use traditional methods for recording home monitoring data. RESULTS 33 of the 35 patients enrolled completed the trial. All 16 patients who began using the phone continued to do so for 6 months confirming the feasibility of the system. Questionnaires completed at 3 and 6 months confirmed the Vista 350 telephone system to be acceptable to the subjects. The results will enable some minor modifications to be made to the telephone system before a larger definitive trial, designed to determine the effect on diabetes control, is conducted later this year.

Introducing QoS to Electronic Commerce Applications

Business to consumer is expected to be one of the fastest growing segments of electronic commerce. One important and challenging problem in such context, is the satisfaction of user expectations about the Quality of Service (QoS) provided when applications are deployed on a large scale. In this paper, we will examine the use of dynamic QoS management techniques in combination with replication at the various architectural levels of an electronic commerce application.

A model for adaptive monitoring configurations

With the increased availability and complexity of distributed systems comes a greater need for solutions to assist in the management of distributed system components. Despite the significant contributions made towards the development of management tools that monitor and control distributed systems, little has been done to address issues such as the cost of management and how it can adapt to the dynamic changes in user requirements as well as system resources. We present an adaptive model in which an initial optimal configuration of management agents is determined according to a set of user/system requirements. These agents can later be dynamically reconfigured to adapt to changes in resource availability and user/system constraints, with minimal effect on the behaviour of the managed system components. Algorithm, prototype, and experimental results are presented.

Supporting dynamic policy change using CORBA system management facilities

Automation of management tasks is an effective counter-measure to the growing complexity of distributed systems. An increasingly popular view redefines the role of the management system to include automated validation and enforcement of policy. This research proposes an architecture for a policy-driven management system which can adapt dynamically to policy change. We show how this architecture can be implemented in a CORBA distributed object computing environment on top of the recently adopted System Management Common Management Facilities.

Towards an improved data centre simulation with DCSim

Computing is increasingly moving into large-scale data centres, providing resources on-demand for clients on a pay-per-usage basis. One form of such on-demand computing is an Infrastructure as a Service (IaaS) Cloud, which provides low level access to virtualized resources. Developing and evaluating data centre management techniques for such large-scale data centres presents a significant challenge. As such, most work turns to simulation tools as the test environment. We present a number of extensions and additional features to an existing simulation tool, DCSim. Our improvements to DCSim include work on the core of the simulator, improved event, communication and management mechanisms, and a more complete model of the structure of a data centre. We also present improved simulation configuration tools and output, including a unique visualization tool. We evaluate the usefulness of the simulator through a demonstration of its use in comparing dynamic VM management techniques.