Distributed Management of Grid-based Scientific Workflows

Grids and service-oriented technologies are emerging as dominant approaches for distributed systems. With the evolution of these technologies, scientific workflows have been introduced as a tool for scientists to assemble highly specialized applications, and to exchange large heterogeneous datasets in order to automate and accelerate the accomplishment of complex scientific tasks. Several Scientific Workflow Management Systems (SWfMS) have already been designed to support the specification, execution, and monitoring of scientific workflows. Meanwhile, they still face key challenges from two different perspectives: system usability and system efficiency. From the system usability perspective, current SWfMS are not designed to be simple enough for scientists who have quite limited IT knowledge. What’s more, there is no easy mechanism by which scientists can share and re-use scientific experiments that have already been designed and proved by others. From the perspective of system efficiency, existing SWfMS are coordinating and executing workflows in a centralized fashion using a single scheduler and / or a workflow enactor. This creates a single point of failure, forms a scalability bottleneck, and enforces centralized fault handling. In addition, they don’t consider load balancing while mapping abstract jobs onto several computational nodes. Another important challenge exists due to the common nature of scientific workflow applications, that need to exchange a huge amount of data during the execution process. Some available SWfMS use a mediator-based approach for data transfer where data must be transferred first to a centralized data manager, which is completely inefficient. Other SWfMS apply a peer-to-peer approach via data references. Even this approach is not sufficient for scientific workflows as a single complex scientific activity can produce an extensive amount of data. In this thesis, we introduce SWIMS (Scientific Workflow Integration and Management System) framework. It employs the Web Services technology to originate a distributed management system for data-intensive scientific workflows. The purpose of SWIMS is to overcome the previously mentioned challenges through a set of salient features: i) Support for distributed execution and management of workflows, ii) diminution of communication traffic, iii) support for smart re-run, iv) distributed fault handling and load balancing, v) ease of use, and vi) extensive sharing of scientific workflows. We discuss the motivation, design, and implementation of the SWIMS framework. Then, we evaluate it through the Montage application from the astronomy domain

An Effective End-User Development Approach Through Domain-Specific Mashups for Research Impact Evaluation

Over the last decade, there has been growing interest in the assessment of the performance of researchers, research groups, universities and even countries. The assessment of productivity is an instrument to select and promote personnel, assign research grants and measure the results of research projects. One particular assessment approach is bibliometrics i.e., the quantitative analysis of scientific publications through citation and content analysis. However, there is little consensus today on how research evaluation should be performed, and it is commonly acknowledged that the quantitative metrics available today are largely unsatisfactory. A number of different scientific data sources available on the Web (e.g., DBLP, Google Scholar) that are used for such analysis purposes. Taking data from these diverse sources, performing the analysis and visualizing results in different ways is not a trivial and straight forward task. Moreover, people involved in such evaluation processes are not always IT experts and hence not capable to crawl data sources, merge them and compute the needed evaluation procedures. The recent emergence of mashup tools has refueled research on end-user development, i.e., on enabling end-users without programming skills to produce their own applications. We believe that the heart of the problem is that it is impractical to design tools that are generic enough to cover a wide range of application domains, powerful enough to enable the specification of non-trivial logic, and simple enough to be actually accessible to non-programmers. This thesis presents a novel approach for an effective end-user development, specifically for non-programmers. That is, we introduce a domain-specific approach to mashups that "speaks the language of users"., i.e., that is aware of the terminology, concepts, rules, and conventions (the domain) the user is comfortable with.Comment: This PhD dissertation consists of 206 page

Assisted Reuse of Pattern-Based Composition Knowledge for Mashup Development

First generation of the World Wide Web (WWW) enabled users to have instantaneous access to a large diversity of knowledge. Second generation of the WWW (Web 2.0) brought a fundamental change in the way people interact with and through the World Wide Web. Web 2.0 has made the World Wide Web a platform not only for communication and sharing information but also for software development (e.g., web service composition). Web mashup or mashup development is a Web2.0 development approach in which users are expected to create applications by combining multiple data sources, application logic and UI components from the web to cater for their situational application needs. However, in reality creating an even simple mashup application is a complex task that can only be managed by skilled developers. Examples of ready mashup models are one of the main sources of help for users who don't know how to design a mashup, provided that suitable examples can be found (examples that have an analogy with the modeling situation faced by the user). But also tutorials, expert colleagues or friends, and, of course, Google are typical means to find help. However, searching for help does not always lead to a success, and retrieved information is only seldom immediately usable as it is, since the retrieved pieces of information are not contextual, i.e., immediately applicable to the given modeling problem. Motivated by the development challenges faced by a naive user of existing mashup tools, in this thesis we propose toaid such users by enabling assisted reuse of pattern-based composition knowledge. In this thesis we show how it is possible to effectively assist these users in their development task with contextual, interactive recommendations of composition knowledge in the form of mashup model patterns. We study a set of recommendation algorithms with different levels of performance and describe a flexible pattern weaving approach for the one-click reuse of patterns. We prove the generality of our algorithms and approach by implementing two prototype tools for two different mashup platforms. Finally, we validate the usefulness of our assisted development approach by performing thorough empirical tests and two user studies with our prototype tools

A service-oriented approach to implementing an adaptive user interface

Service-oriented architectures (SOA) are being adopted by organisations in order to integrate disparate computational assets. A major hurdle they face is the decision on how to integrate the UI in an SOA. In addition, technological advances have allowed complex applications and complex user interfaces (UIs) to be realised and the increase in accessibility to computers enables a diverse population of users with different characteristics, preferences and needs to use these complex computer applications. Adaptive user interfaces (AUIs) have been proposed as a solution to cater for the differences in user traits by adapting the UI to meet the diverse needs of users. AUIs have, however, traditionally been developed using client/server architectures This research, therefore, set out to investigate how to develop an AUI using a service-oriented architecture (SOA). In order to successfully achieve the goal of this research, literature concerning SOAs was investigated to gain an understanding of SOAs. A literature review of AUIs was also undertaken to gain an understanding of AUIs. A model-based approach was used to develop a model for UI adaptation using knowledge gained in the literature reviews. The model generates different UIs depending on various users‘ inferred level of expertise. The model describes the interaction between AUI services that use design-time documents and run-time user-interaction to adapt the UI. A prototype of the model was implemented and evaluated using an evolution strategy devised to assess different aspects of the research. The evaluation strategy proved the following: The service components of the prototype adhere to SOA design principles; The implementation was effective based on software engineering metrics; and, The implementation was usable and did not negatively affect the performance of users. The successful implementation of the prototype provides evidence that the design of AUIs using SOA is feasible. This dissertation therefore makes a contribution to the development of AUIs using SOAs. The model could be used to provide UI adaptation for business software applications