QoS-Aware Middleware for Web Services Composition

The paradigmatic shift from a Web of manual interactions to a Web of programmatic interactions driven by Web services is creating unprecedented opportunities for the formation of online Business-to-Business (B2B) collaborations. In particular, the creation of value-added services by composition of existing ones is gaining a significant momentum. Since many available Web services provide overlapping or identical functionality, albeit with different Quality of Service (QoS), a choice needs to be made to determine which services are to participate in a given composite service. This paper presents a middleware platform which addresses the issue of selecting Web services for the purpose of their composition in a way that maximizes user satisfaction expressed as utility functions over QoS attributes, while satisfying the constraints set by the user and by the structure of the composite service. Two selection approaches are described and compared: one based on local (task-level) selection of services and the other based on global allocation of tasks to services using integer programming

Cloudbus Toolkit for Market-Oriented Cloud Computing

This keynote paper: (1) presents the 21st century vision of computing and identifies various IT paradigms promising to deliver computing as a utility; (2) defines the architecture for creating market-oriented Clouds and computing atmosphere by leveraging technologies such as virtual machines; (3) provides thoughts on market-based resource management strategies that encompass both customer-driven service management and computational risk management to sustain SLA-oriented resource allocation; (4) presents the work carried out as part of our new Cloud Computing initiative, called Cloudbus: (i) Aneka, a Platform as a Service software system containing SDK (Software Development Kit) for construction of Cloud applications and deployment on private or public Clouds, in addition to supporting market-oriented resource management; (ii) internetworking of Clouds for dynamic creation of federated computing environments for scaling of elastic applications; (iii) creation of 3rd party Cloud brokering services for building content delivery networks and e-Science applications and their deployment on capabilities of IaaS providers such as Amazon along with Grid mashups; (iv) CloudSim supporting modelling and simulation of Clouds for performance studies; (v) Energy Efficient Resource Allocation Mechanisms and Techniques for creation and management of Green Clouds; and (vi) pathways for future research.Comment: 21 pages, 6 figures, 2 tables, Conference pape

Distributed Web Service Coordination for Collaboration Applications and Biological Workflows

In this dissertation work, we have investigated the main research thrust of decentralized coordination of workflows over web services. To address distributed workflow coordination, first we have developed “Web Coordination Bonds” as a capable set of dependency modeling primitives that enable each web service to manage its own dependencies. Web bond primitives are as powerful as extended Petri nets and have sufficient modeling and expressive capabilities to model workflow dependencies. We have designed and prototyped our “Web Service Coordination Management Middleware” (WSCMM) system that enhances current web services infrastructure to accommodate web bond enabled web services. Finally, based on core concepts of web coordination bonds and WSCMM, we have developed the “BondFlow” system that allows easy configuration distributed coordination of workflows. The footprint of the BonFlow runtime is 24KB and the additional third party software packages, SOAP client and XML parser, account for 115KB

A Methodology for Engineering Collaborative and ad-hoc Mobile Applications using SyD Middleware

Today’s web applications are more collaborative and utilize standard and ubiquitous Internet protocols. We have earlier developed System on Mobile Devices (SyD) middleware to rapidly develop and deploy collaborative applications over heterogeneous and possibly mobile devices hosting web objects. In this paper, we present the software engineering methodology for developing SyD-enabled web applications and illustrate it through a case study on two representative applications: (i) a calendar of meeting application, which is a collaborative application and (ii) a travel application which is an ad-hoc collaborative application. SyD-enabled web objects allow us to create a collaborative application rapidly with limited coding effort. In this case study, the modular software architecture allowed us to hide the inherent heterogeneity among devices, data stores, and networks by presenting a uniform and persistent object view of mobile objects interacting through XML/SOAP requests and responses. The performance results we obtained show that the application scales well as we increase the group size and adapts well within the constraints of mobile devices

Designing Secure Access Control Model in Cyber Social Networks

Nowadays, information security in online communication has become an indisputable topic. People prefer pursuing their connection and public relations due to the greater flexibility and affordability of online communication. Recently, organizations have established online networking sites concerned with sharing assets among their employees. As more people engage in social network, requirements for protecting information and resources becomes vital. Over the years, many access control methods have been proposed. Although these methods cover various information security aspects, they have not provided an appropriate approach for securing information within distributed online networking sites. Moreover, none of the previous research provides an access control method in case an existing resource encompassing various parts and each part has its own accessing control policy. In this research, we investigate the access control requirements in order to conserve data and encompassed resources, which are shared in the social network, from users with unapproved access. Under the proposed method, users are able to define policies easily to protect their individual information and resources from unauthorized users. In addition, requestors are able to generate inquiries in easy and efficient way. We define an appropriate format to present rules and queries, which are converted from policies and inquiries respectively. The proposed approach defines a method in case a user would like to access a resource belonging to another user where both users are members of different online networking sites. In order to add more flexibility, this method controls access to data and resources by evaluating requestor’s attributes, object’s attributes, action or operation taken by requestor, environmental condition, and policies which are created by users or a super user of social network to protect the users’ resources. This approach is called Policy-Based Attribute Access Control (PBAAC). The policies defined to secure a resource may conflict with other policies. The proposed method offers an appropriate solution to resolve this issue. Due to achievement of better performance with regards to efficiency, this research analyzes the method to compromise simple rules, complex rules, or rules including several attributes. The results prove that simple rules provide better performance

Access and information flow control to secure mobile web service compositions in resource constrained environments

The growing use of mobile web services such as electronic health records systems and applications like twitter, Facebook has increased interest in robust mechanisms for ensuring security for such information sharing services. Common security mechanisms such as access control and information flow control are either restrictive or weak in that they prevent applications from sharing data usefully, and/or allow private information leaks when used independently. Typically, when services are composed there is a resource that some or all of the services involved in the composition need to share. However, during service composition security problems arise because the resulting service is made up of different services from different security domains. A key issue that arises and that we address in this thesis is that of enforcing secure information flow control during service composition to prevent illegal access and propagation of information between the participating services. This thesis describes a model that combines access control and information flow control in one framework. We specifically consider a case study of an e-health service application, and consider how constraints like location and context dependencies impact on authentication and authorization. Furthermore, we consider how data sharing applications such as the e-health service application handle issues of unauthorized users and insecure propagation of information in resource constrained environments¹. Our framework addresses this issue of illegitimate information access and propagation by making use of the concept of program dependence graphs (PDGs). Program dependence graphs use path conditions as necessary conditions for secure information flow control. The advantage of this approach to securing information sharing is that, information is only propagated if the criteria for data sharing are verified. Our solution proposes or offers good performance, fast authentication taking into account bandwidth limitations. A security analysis shows the theoretical improvements our scheme offers. Results obtained confirm that the framework accommodates the CIA-triad (which is the confidentiality, integrity and availability model designed to guide policies of information security) of our work and can be used to motivate further research work in this field

PLACES'10: The 3rd Workshop on Programmng Language Approaches to concurrency and Communication-Centric Software

Paphos, Cyprus. March 201

Current Practices for Product Usability Testing in Web and Mobile Applications

Software usability testing is a key methodology that ensures applications are intuitive and easy to use for the target audience. Usability testing has direct benefits for companies as usability improvements often are fundamental to the success of a product. A standard usability test study includes the following five steps: obtain suitable participants, design test scripts, conduct usability sessions, interpret test outcomes, and produce recommendations. Due to the increasing importance for more usable applications, effective techniques to develop usable products, as well as technologies to improve usability testing, have been widely utilized. However, as companies are developing more cross-platform web and mobile apps, traditional single-platform usability testing has shortcomings with respect to ensuring a uniform user experience. In this report, a new strategy is proposed to promote a consistent user experience across all application versions and platforms. This method integrates the testing of different application versions, e.g., the website, mobile app, mobile website. Participants are recruited with a better-defined criterion according to their preferred devices. The usability session is conducted iteratively on several different devices, and the test results of individual application versions are compared on a per-device basis to improve the test outcomes. This strategy is expected to extend on current practices for usability testing by incorporating cross-platform consistency of software versions on most devices