Design tools for event-driven software systems

Proposes a design method for the development of software in Visual BASIC whose programming environment is multi-paradigm. Extensions to structure charts and pseudocode to incorporate the three paradigms have been developed based on the premise that procedural models, event-driven forms and objects are mutually exclusive in operation.

Lease based addressing for event-driven wireless sensor networks

Sensor Networks have applications in diverse fields. They can be deployed for habitat modeling, temperature monitoring and industrial sensing. They also find applications in battlefield awareness and emergency (first) response situations. While unique addressing is not a requirement of many data collecting applications of wireless sensor networks it is vital for the success of applications such as emergency response. Data that cannot be associated with a specific node becomes useless in such situations. In this work we propose an addressing mechanism for event-driven wireless sensor networks. The proposed scheme eliminates the need for network wide Duplicate Address Detection (DAD) and enables reuse of addresses.

Service migration in autonomic service oriented grids

The introduction of Web services into grids helped to address their two main obstacles to be embraced by business and industry, heterogeneity and useability. However, many problems are still open, e.g., grid reconfiguration, reliability and computing optimization. We argue here that a mechanism that could help solving these problems is Web Service migration, a part of automatic and transparent brokerage. Web service migration presents a number of new requirements not addressed in traditional process migration, being the outcome of Web services specific configuration of hosts and application servers, and availability of Web services / resources state. In this paper we report on our study into the development of a Web service migration facility focused on providing migration of services in a Service Oriented Grid environment. We present a novel approach to Web service migration, embodied in a System Management Broker, which is transparent, interoperable and flexible. We take the requirements of Web services into consideration when discovering suitable destination hosts and match services to suitable grid resources which are able to fulfil the needs of the service. We discuss a number of experiments conducted with different types of grid and Web service applications to highlight the feasibility and effectiveness of our migration facility and demonstrate how our facility significantly improves Service Oriented Grids.

Programmer friendly and efficient distributed shared memory integrated into a distributed operating system

Distributed Shared Memory (DSM) provides programmers with a shared memory environment in systems where memory is not physically shared. Clusters of Workstations (COWs), an often untapped source of computing power, are characterised by a very low cost/performance ratio. The combination of Clusters of Workstations (COWs) with DSM provides an environment in which the programmer can use the well known approaches and methods of programming for physically shared memory systems and parallel processing can be carried out to make full use of the computing power and cost advantages of the COW. The aim of this research is to synthesise and develop a distributed shared memory system as an integral part of an operating system in order to provide application programmers with a convenient environment in which the development and execution of parallel applications can be done easily and efficiently, and which does this in a transparent manner. Furthermore, in order to satisfy our challenging design requirements we want to demonstrate that the operating system into which the DSM system is integrated should be a distributed operating system. In this thesis a study into the synthesis of a DSM system within a microkernel and client-server based distributed operating system which uses both strict and weak consistency models, with a write-invalidate and write-update based approach for consistency maintenance is reported. Furthermore a unique automatic initialisation system which allows the programmer to start the parallel execution of a group of processes with a single library call is reported. The number and location of these processes are determined by the operating system based on system load information. The DSM system proposed has a novel approach in that it provides programmers with a complete programming environment in which they are easily able to develop and run their code or indeed run existing shared memory code. A set of demanding DSM system design requirements are presented and the incentives for the placement of the DSM system with a distributed operating system and in particular in the memory management server have been reported. The new DSM system concentrated on an event-driven set of cooperating and distributed entities, and a detailed description of the events and reactions to these events that make up the operation of the DSM system is then presented. This is followed by a pseudocode form of the detailed design of the main modules and activities of the primitives used in the proposed DSM system. Quantitative results of performance tests and qualitative results showing the ease of programming and use of the RHODOS DSM system are reported. A study of five different application is given and the results of tests carried out on these applications together with a discussion of the results are given. A discussion of how RHODOS’ DSM allows programmers to write shared memory code in an easy to use and familiar environment and a comparative evaluation of RHODOS DSM with other DSM systems is presented. In particular, the ease of use and transparency of the DSM system have been demonstrated through the description of the ease with which a moderately inexperienced undergraduate programmer was able to convert, write and run applications for the testing of the DSM system. Furthermore, the description of the tests performed using physically shared memory shows that the latter is indistinguishable from distributed shared memory; this is further evidence that the DSM system is fully transparent. This study clearly demonstrates that the aim of the research has been achieved; it is possible to develop a programmer friendly and efficient DSM system fully integrated within a distributed operating system. It is clear from this research that client-server and microkernel based distributed operating system integrated DSM makes shared memory operations transparent and almost completely removes the involvement of the programmer beyond classical activities needed to deal with shared memory. The conclusion can be drawn that DSM, when implemented within a client-server and microkernel based distributed operating system, is one of the most encouraging approaches to parallel processing since it guarantees performance improvements with minimal programmer involvement.

Address reuse in wireless sensor networks

Sensor Networks have applications in diverse fields. While unique addressing is not a requirement of many data collecting applications of wireless sensor networks, it is vital for the success of applications such as emergency response. Data that cannot be associated with a specific node becomes useless in such situations. In this work we propose a dynamic addressing mechanism for wireless sensor networks. The scheme enables successful reuse of addresses in event-driven wireless sensor networks. It also eliminates the need for network-wide Duplicate Address Detection (DAD) to ensure uniqueness of network level addresses.

Dynamic addressing in wireless sensor networks without location awareness

Sensor Networks have applications in diverse fields. They can be deployed for habitat modeling, temperature monitoring and industrial sensing. They also find applications in battlefield awareness and emergency (first) response situations. While unique addressing is not a requirement of many data collecting applications of wireless sensor networks, it is vital for the success of applications such as emergency response. Data that cannot be associated with a specific node becomes useless in such situations. In this work we propose a novel dynamic addressing mechanism for wireless sensor networks that are not location-aware. The scheme enables successful reuse of addresses in event-driven wireless sensor networks introducing minimal latencies and efficiently addressing packet loss. It also eliminates the need for network-wide Duplicate Address Detection (DAD) to ensure uniqueness of network level addresses.

Adaptable, model-driven security engineering for SaaS cloud-based applications

Software-as-a-service (SaaS) multi-tenancy in cloud-based applications helps service providers to save cost, improve resource utilization, and reduce service customization and maintenance time. This is achieved by sharing of resources and service instances among multiple "tenants" of the cloud-hosted application. However, supporting multi-tenancy adds more complexity to SaaS applications required capabilities. Security is one of these key requirements that must be addressed when engineering multi-tenant SaaS applications. The sharing of resources among tenants - i.e. multi-tenancy - increases tenants' concerns about the security of their cloud-hosted assets. Compounding this, existing traditional security engineering approaches do not fit well with the multi-tenancy application model where tenants and their security requirements often emerge after the applications and services were first developed. The resultant applications do not usually support diverse security capabilities based on different tenants' needs, some of which may change at run-time i.e. after cloud application deployment. We introduce a novel model-driven security engineering approach for multi-tenant, cloud-hosted SaaS applications. Our approach is based on externalizing security from the underlying SaaS application, allowing both application/service and security to evolve at runtime. Multiple security sets can be enforced on the same application instance based on different tenants' security requirements. We use abstract models to capture service provider and multiple tenants' security requirements and then generate security integration and configurations at runtime. We use dependency injection and dynamic weaving via Aspect-Oriented Programming (AOP) to integrate security within critical application/service entities at runtime. We explain our approach, architecture and implementation details, discuss a usage example, and present an evaluation of our approach on a set of open source web applications.

Successful web-based IT support services : service provider perceptions of stakeholder-oriented challenges

Web-based self-service systems (WSSs) are increasingly leveraged for the delivery of after-sales information technology (IT) support services. Such services are offered by IT service providers to customer firms and increasingly involve business partners. However little is known of the challenges faced by IT service providers as a result of the involvement of the other firms and their employees (end-users). This paper reports related findings from an interpretive study of IT service provider perceptions in six multinational IT service provider firms (Cooper, 2007). The findings highlight that, for IT service providers, (1) it is important to consider and resolve the needs and concerns of other key stakeholders, and (2) significant challenges exist in doing so. The main contribution of the paper is the identification of the key challenges involved. Important implications for theory and practice are discussed.

Interoperable and transparent dynamic deployment of web services for service oriented grids

Dynamic deployment of Web services is a term used frequently when describing the selection and deployment of a service to a grid host. Although current grid systems (such as Globus) provide dynamic deployment, the requirements of the service being deployed are not considered. Therefore truly dynamic deployment cannot be achieved as the services deployed are restricted to the grid system used. We present a dynamic deployment mechanism as part of self configuration in a service oriented grid environment. The dynamic deployment mechanism takes the requirements of the service into consideration, including parameters such as the operating system required to execute the service, the required software libraries, any additional required software packages, price and Quality of Service (QoS) parameters.

Protecting web services with service oriented traceback architecture

Service oriented architecture (SOA) is a way of reorganizing software infrastructure into a set of service abstracts. In the area of applying SOA to Web service security, there have been some well defined security dimensions. However, current Web security systems, like WS-Security are not efficient enough to handle distributed denial of service (DDoS) attacks. Our new approach, service oriented traceback architecture (SOTA), provides a framework to be able to identify the source of an attack. This is accomplished by deploying our defence system at distributed routers, in order to examine the incoming SOAP messages and place our own SOAP header. By this method, we can then use the new SOAP header information, to traceback through the network the source of the attack. According to our experimental performance evaluations, we find that SOTA is quite scaleable, simple and quite effective at identifying the source.

Enhanced mechanical energy harvesting using needleless electrospun poly(vinylidene fluoride) nanofibre web

Randomly oriented poly(vinylidene fluoride) (PVDF) nanofibre webs prepared by a needleless electrospinning technique were used as an active layer for making mechanical-to-electrical energy harvest devices. With increasing the applied voltage in the electrospinning process, a higher b crystal phase was formed in the resulting PVDF nanofibres, leading to enhanced mechanical-to-electrical energy conversion of the devices. The power generated by the nanofibre devices was able to drive a miniature Peltier cooler, which may be useful for the development of mechanically driven cooling textile. In addition, the needleless electrospinning also showed great potential in the production of nanofibres on a large scale.

Domain-driven classification based on multiple criteria and multiple constraint-level programming for intelligent credit scoring

Extracting knowledge from the transaction records and the personal data of credit card holders has great profit potential for the banking industry. The challenge is to detect/predict bankrupts and to keep and recruit the profitable customers. However, grouping and targeting credit card customers by traditional data-driven mining often does not directly meet the needs of the banking industry, because data-driven mining automatically generates classification outputs that are imprecise, meaningless, and beyond users' control. In this paper, we provide a novel domain-driven classification method that takes advantage of multiple criteria and multiple constraint-level programming for intelligent credit scoring. The method involves credit scoring to produce a set of customers' scores that allows the classification results actionable and controllable by human interaction during the scoring process. Domain knowledge and experts' experience parameters are built into the criteria and constraint functions of mathematical programming and the human and machine conversation is employed to generate an efficient and precise solution. Experiments based on various data sets validated the effectiveness and efficiency of the proposed methods. © 2006 IEEE.

Requirements engineering for web-based information systems

This chapter overviews the existing methods of requirements analysis as prescribed by some of the best-known web-development methods. It also discusses the pre-eminent importance of stakeholder analysis, identification of stakeholder views and concerns, and the processes governing elicitation of web systems requirements. The chapter finally derives a model of concern-driven requirements evolution from several case studies undertaken in the area of web-enabled employee service systems.