517,589 research outputs found

    Flexible provisioning of Web service workflows

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    Web services promise to revolutionise the way computational resources and business processes are offered and invoked in open, distributed systems, such as the Internet. These services are described using machine-readable meta-data, which enables consumer applications to automatically discover and provision suitable services for their workflows at run-time. However, current approaches have typically assumed service descriptions are accurate and deterministic, and so have neglected to account for the fact that services in these open systems are inherently unreliable and uncertain. Specifically, network failures, software bugs and competition for services may regularly lead to execution delays or even service failures. To address this problem, the process of provisioning services needs to be performed in a more flexible manner than has so far been considered, in order to proactively deal with failures and to recover workflows that have partially failed. To this end, we devise and present a heuristic strategy that varies the provisioning of services according to their predicted performance. Using simulation, we then benchmark our algorithm and show that it leads to a 700% improvement in average utility, while successfully completing up to eight times as many workflows as approaches that do not consider service failures

    Exploring the Sources of Enterprise Agility in Software Organizations

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    Organizations involved in the design, development and sustainment of software systems have to manage the tension between creating new products and services, while at the same time maintaining their existing portfolio. This paper explores the sources of enterprise agility in software firms, wherein agility is defined as the ability of the organization to sense changes in its environment (both internal and external), and effectively respond to these changes. Using engaged scholarship as the overarching paradigm, we report on the findings of a process study that uses semi-structured interviews, observation, and archival firm & project information for data gathering, and grounded theory methods and comparative case analysis for data analysis and theory generation. The analysis highlights the importance of the four organizational enablers of: stakeholder alignment, employee empowerment, group & organizational learning, and governance mechanisms, as necessary but not sufficient precursors to obtaining enterprise agility. Furthermore, we provide illustrative case examples of the three mechanisms: Continuous Improvement, Creating Systems of Innovation, and Leveraging Globally available Capabilities, that software organizations use to gain enterprise agility

    Lean and complex systems : a case study of materials handling at an on-land warehouse facility supporting subsea gas operations

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    Commonly warehouse management is subject to deterministic planning procedures within the organizational scope of supply chain management. Lately lean principles have become more widespread and also adapted to develop materials handling within warehouses. Several facets of analysis are considered in this case study on outsourced warehousing in the Norwegian petroleum industry. This study reveals empirically how outsourced warehousing as service provision involves an organization problem with waste found both at the service management and at the process levels. Analysis points to how lean principles of process improvement may be combined with complex systems thinking. The case reveals examples of how warehouse management and its operations are full of complexities leading to waste. While lean usually is used hands on to manage these wastes through manual incremental development, another organisation of continuous innovation is suggested here. Lean is suggested be developed as organizational context of complex systems information warehouse management system software. Following lean principles evokes many types of process waste at the studied warehouse. Instead on following the manual stepwise and continuous process improvement approach of lean in all areas of organization, a more radical change to complex systems evident in information system design to support warehousing processes is proposed with lean as its organizational context. Keywords: case study, complex systems, lean, material handling, Norwegian petroleum industry, services industry, Warehouse managementpublishedVersio

    Space Plug-and-Play Architecture Networking: A Self-Configuring Heterogeneous Network Architecture

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    The Space Plug-and-Play Architecture (SPA) networking approach outlined in this dissertation is an improvement over the previous approach used by the Satellite Data Model(SDM). The first improvement is the introduction of a SPA network model based on the Open Systems Interconnection (OSI) model. Second, a new addressing and routing scheme is presented, which places the burden of routing on the network infrastructure instead of the network endpoints. These improvements have been implemented in a software infrastructure called the SPA Services Manager (SSM). The SSM was developed under an International Organization for Standardization (ISO) 9001 certified development process, the details of which are presented. A collection of network timing graphs that measure latency and jitter of the SPA network is contained in this dissertation, as well as a runtime memory footprint. The maturity of the development process and these initial performance measurements demonstrate that the SSM is qualified for spaceflight

    Security Analysis and Improvement Model for Web-based Applications

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    Today the web has become a major conduit for information. As the World Wide Web?s popularity continues to increase, information security on the web has become an increasing concern. Web information security is related to availability, confidentiality, and data integrity. According to the reports from http://www.securityfocus.com in May 2006, operating systems account for 9% vulnerability, web-based software systems account for 61% vulnerability, and other applications account for 30% vulnerability. In this dissertation, I present a security analysis model using the Markov Process Model. Risk analysis is conducted using fuzzy logic method and information entropy theory. In a web-based application system, security risk is most related to the current states in software systems and hardware systems, and independent of web application system states in the past. Therefore, the web-based applications can be approximately modeled by the Markov Process Model. The web-based applications can be conceptually expressed in the discrete states of (web_client_good; web_server_good, web_server_vulnerable, web_server_attacked, web_server_security_failed; database_server_good, database_server_vulnerable, database_server_attacked, database_server_security_failed) as state space in the Markov Chain. The vulnerable behavior and system response in the web-based applications are analyzed in this dissertation. The analyses focus on functional availability-related aspects: the probability of reaching a particular security failed state and the mean time to the security failure of a system. Vulnerability risk index is classified in three levels as an indicator of the level of security (low level, high level, and failed level). An illustrative application example is provided. As the second objective of this dissertation, I propose a security improvement model for the web-based applications using the GeoIP services in the formal methods. In the security improvement model, web access is authenticated in role-based access control using user logins, remote IP addresses, and physical locations as subject credentials to combine with the requested objects and privilege modes. Access control algorithms are developed for subjects, objects, and access privileges. A secure implementation architecture is presented. In summary, the dissertation has developed security analysis and improvement model for the web-based application. Future work will address Markov Process Model validation when security data collection becomes easy. Security improvement model will be evaluated in performance aspect

    PENINGKATAN PELAYANAN JASA KONSULTAN LINGKUNGAN HIDUP DENGAN PENGEMBANGAN WEBSITE CV FAHMI JAYA

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    Research on the improvement of environmental consulting services with the development of the CV website. Fahmi  Jaya is a research to make it easier for the public to obtain complete and up-to-date information because information is felt to be very important in making decisions and in achieving goals. In addition to obtaining complete and up-to-date information, the website can also send and publish information to the wider community online. The system development method used in this research is the System Development Life Cycle (SDLC) method, or better known as the system development life cycle in system engineering and software engineering, is the process of making and changing systems and the models and methodologies used to develop these systems. The results of the research are expected that this system can publish its activities for more recent information so that the public can find out the activities that have been carried out, the ease of information about CV FAHMI JAYA

    Contribution to Quality-driven Evolutionary Software Development process for Service-Oriented Architectures

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    The quality of software is a key element for the successful of a system. Currently, with the advance of the technology, consumers demand more and better services. Models for the development process have also to be adapted to new requirements. This is particular true in the case of service oriented systems (domain of this thesis), where an unpredictable number of users can access to one or several services. This work proposes an improvement in the models for the software development process based on the theory of the evolutionary software development. The main objective is to maintain and improve the quality of software as long as possible and with the minimum effort and cost. Usually, this process is supported on methods known in the literature as agile software development methods. Other key element in this thesis is the service oriented software architecture. Software architecture plays an important role in the quality of any software system. The Service oriented architecture adds the service flexibility, the services are autonomous and compact assets, and they can be improved and integrated with better facility. The proposed model in this thesis for evolutionary software development makes emphasis in the quality of services. Therefore, some principles of evolutionary development are redefined and new processes are introduced, such as: architecture assessment, architecture recovery and architecture conformance. Every new process will be evaluated with case studies considering quality aspects. They have been selected according to the market demand, they are: the performance, security and evolutionability. Other aspects could be considered of the same way than the three previous, but we believe that these quality attributes are enough to demonstrate the viability of our proposal

    Evolution of Software Testing Strategies and Trends: Semantic Content Analysis of Software Research Corpus of the Last 40 Years

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    From the early days of computer systems to the present, software testing has been considered as a crucial process that directly affects the quality and reliability of software-oriented products and services. Accordingly, there is a huge amount of literature regarding the improvement of software testing approaches. However, there are limited reviews that show the whole picture of the software testing studies covering the topics and trends of the field. This study aims to provide a general figure reflecting topics and trends of software testing by analyzing the majority of software testing articles published in the last 40 years. A semi-automated methodology is developed for the analysis of software testing corpus created from core publication sources. The methodology of the study is based on the implementation of probabilistic topic modeling approach to discover hidden semantic patterns in the 14,684 published articles addressing software testing issues between 1980 and 2019. The results revealed 42 topics of the field, highlighting five software development ages, namely specification, detection, generation, evaluation, and prediction. The recent accelerations of the topics also showed a trend toward prediction-based software testing actions. Additionally, a higher trend on the topics concerning “Security Vulnerability”, “Open Source” and “Mobile Application” was identified. This study showed that the current trend of software testing is towards prediction-based testing strategies. Therefore, the findings of this study may provide valuable insights for the industry and software communities to be prepared for the possible changes in the software testing procedures using prediction-based approaches.publishedVersio

    A Software Product Line Approach to Ontology-based Recommendations in E-Tourism Systems

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    This study tackles two concerns of developers of Tourism Information Systems (TIS). First is the need for more dependable recommendation services due to the intangible nature of the tourism product where it is impossible for customers to physically evaluate the services on offer prior to practical experience. Second is the need to manage dynamic user requirements in tourism due to the advent of new technologies such as the semantic web and mobile computing such that etourism systems (TIS) can evolve proactively with emerging user needs at minimal time and development cost without performance tradeoffs. However, TIS have very predictable characteristics and are functionally identical in most cases with minimal variations which make them attractive for software product line development. The Software Product Line Engineering (SPLE) paradigm enables the strategic and systematic reuse of common core assets in the development of a family of software products that share some degree of commonality in order to realise a significant improvement in the cost and time of development. Hence, this thesis introduces a novel and systematic approach, called Product Line for Ontology-based Tourism Recommendation (PLONTOREC), a special approach focusing on the creation of variants of TIS products within a product line. PLONTOREC tackles the aforementioned problems in an engineering-like way by hybridizing concepts from ontology engineering and software product line engineering. The approach is a systematic process model consisting of product line management, ontology engineering, domain engineering, and application engineering. The unique feature of PLONTOREC is that it allows common TIS product requirements to be defined, commonalities and differences of content in TIS product variants to be planned and limited in advance using a conceptual model, and variant TIS products to be created according to a construction specification. We demonstrated the novelty in this approach using a case study of product line development of e-tourism systems for three countries in the West-African Region of Africa
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