449 research outputs found

    A systematic review on cloud testing

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    A systematic literature review is presented that surveyed the topic of cloud testing over the period (2012-2017). Cloud testing can refer either to testing cloud-based systems (testing of the cloud), or to leveraging the cloud for testing purposes (testing in the cloud): both approaches (and their combination into testing of the cloud in the cloud) have drawn research interest. An extensive paper search was conducted by both automated query of popular digital libraries and snowballing, which resulted into the final selection of 147 primary studies. Along the survey a framework has been incrementally derived that classifies cloud testing research along six main areas and their topics. The paper includes a detailed analysis of the selected primary studies to identify trends and gaps, as well as an extensive report of the state of art as it emerges by answering the identified Research Questions. We find that cloud testing is an active research field, although not all topics have received so far enough attention, and conclude by presenting the most relevant open research challenges for each area of the classification framework.This paper describes research work mostly undertaken in the context of the European Project H2020 731535: ElasTest. This work has also been partially supported by: the Italian MIUR PRIN 2015 Project: GAUSS; the Regional Government of Madrid (CM) under project Cloud4BigData (S2013/ICE-2894) cofunded by FSE & FEDER; and the Spanish Government under project LERNIM (RTC-2016-4674-7) cofunded by the Ministry of Economy and Competitiveness, FEDER & AEI

    Model-based testing

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    Рассмотрено тестирование на основе моделей, преимущества данного подхода. Затронута возможность использования облачных вычислений при модульном тестировании. А также описаны необходимые требования для автоматизированного тестирование на основе моделей. The paper considers model-based testing, the advantages of this approach. The possibility of using cloud computing in unit testing is touched upon. It also describes the necessary requirements for automated model-based testing

    Understanding SE Growth: The Case of Bangladesh

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    This thesis seeks to explore the hybrid nature of Social Enterprises (SEs) by investigating how they incorporate co-existence of social and economic goals and embed in multiple institutional domains. By synthesising insights from three literature domains - hybrid organisations, institutional views and strategic management - this thesis advances the understanding about the hybrid nature of SEs mainly in two ways. First, it examines the extent to which managerial tensions may result in hybrid SEs due to co-existence of values and influences from pluralistic institutional domains. Second, it explores how such organisations mobilise resources and capabilities in order to respond to internal tensions. The three research questions addressed in the thesis are: i) What is the nature of SE growth in Bangladesh?; ii) How does the institutional context influence SE growth in Bangladesh? and iii) What role do SEs’ resources and capabilities play in responding to the institutional influences? The study adopts a multiple case study approach, collecting data from eleven Bangladeshi SEs. With rapid rise of hybrid forms of SEs in Bangladesh, the findings of the study have both practical and policy implications. The insights on SEs’ internal tensions can enable Bangladeshi policy makers to realise the needs and challenges of hybrid SEs in the country. This may aid the development of customised policies, incentives and support systems that are required to facilitate the growth of such organisations. The insights on the management of tensions can aid the leaders and managers in hybrid SEs to respond to their internal tensions more appropriately.The study identifies six operational models through analysis of the social goal, economic mission, income source, governance structure and institutional setting of the studied cases. These models are: SEs that are fully reliant on grant, NGOs with trading elements, NGOs with full reliance on trading, social business es, public and private limited corporations, and NGOs with conventional subsidiary enterprise. The findings further showed that the studied SEs have pursued social and economic goals simultaneously through adoption of four growth strategies: expansion, diversification, autonomous growth and partnership. The study identifies a number of competing pressures originating from multiple institutional domains which have affected the way they accomplished their social and economic goals. This interplay between SEs’ dual goals and institutional influences led to ten different tensions inside the studied cases. The management of these tensions, at the functional level, involved orchestration of SEs’ resources and capabilities in a particular way. The specific ways of mobilisation of resources and capabilities ultimately led the SEs towards five different growth paths: i) forced adoption/coercive adoption, ii) proactive response, iii) adapt, iv) influence, and v) side-stepping

    The countryside in urbanized Flanders: towards a flexible definition for a dynamic policy

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    The countryside, the rural area, the open space, … many definitions are used for rural Flanders. Everyone makes its own interpretation of the countryside, considering it as a place for living, working or recreating. The countryside is more than just a geographical area: it is an aggregate of physical, social, economic and cultural functions, strongly interrelated with each other. According to international and European definitions of rural areas there would be almost no rural area in Flanders. These international definitions are all developed to be used for analysis and policy within their specific context. They are not really applicable to Flanders because of the historical specificity of its spatial structure. Flanders is characterized by a giant urbanization pressure on its countryside while internationally rural depopulation is a point of interest. To date, for every single rural policy initiative – like the implementation of the European Rural Development Policy – Flanders used a specifically adapted definition, based on existing data or previously made delineations. To overcome this oversupply of definitions and delineations, the Flemish government funded a research project to obtain a clear and flexible definition of the Flemish countryside and a dynamic method to support Flemish rural policy aims. First, an analysis of the currently used definitions of the countryside in Flanders was made. It is clear that, depending on the perspective or the policy context, another definition of the countryside comes into view. The comparative study showed that, according to the used criteria, the area percentage of Flanders that is rural, varies between 9 and 93 per cent. Second, dynamic sets of criteria were developed, facilitating a flexible definition of the countryside, according to the policy aims concerned. This research part was focused on 6 policy themes, like ‘construction, maintenance and management of local (transport) infrastructures’ and ‘provision of (minimum) services (education, culture, health care, …)’. For each theme a dynamic set of criteria or indicators was constructed. These indicators make it possible to show where a policy theme manifests itself and/or where policy interventions are possible or needed. In this way every set of criteria makes up a new definition of rural Flanders. This method is dynamic; new data or insights can easily be incorporated and new criteria sets can be developed if other policy aims come into view. The developed method can contribute to a more region-oriented and theme-specific rural policy and funding mechanism

    Guidelines for the analysis of student web usage in support of primary educational objectives

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    The Internet and World Wide Web provides huge amounts of information to individuals with access to it. Information is an important driving factor of education and higher education has experienced massive adoption rates of information and communication technologies, and accessing the Web is not an uncommon practice within a higher educational institution. The Web provides numerous benefits and many students rely on the Web for information, communication and technical support. However, the immense amount of information available on the Web has brought about some negative side effects associated with abundant information. Whether the Web is a positive influence on students’ academic well-being within higher education is a difficult question to answer. To understand how the Web is used by students within a higher education institution is not an easy task. However, there are ways to understand the Web usage behaviour of students. Using established methods for gathering useful information from data produced by an institution, Web usage behaviours of students within a higher education institution could be analysed and presented. This dissertation presents guidance for analysing Web traffic within a higher educational institution in order to gain insight into the Web usage behaviours of students. This insight can provide educators with valuable information to bolster their decision-making capacity towards achieving their educational goals

    Towards an Expert System for the Analysis of Computer Aided Human Performance

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    Improving Demand Forecasting: The Challenge of Forecasting Studies Comparability and a Novel Approach to Hierarchical Time Series Forecasting

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    Bedarfsprognosen sind in der Wirtschaft unerlässlich. Anhand des erwarteten Kundenbe-darfs bestimmen Firmen beispielsweise welche Produkte sie entwickeln, wie viele Fabri-ken sie bauen, wie viel Personal eingestellt wird oder wie viel Rohmaterial geordert wer-den muss. Fehleinschätzungen bei Bedarfsprognosen können schwerwiegende Auswir-kungen haben, zu Fehlentscheidungen führen, und im schlimmsten Fall den Bankrott einer Firma herbeiführen. Doch in vielen Fällen ist es komplex, den tatsächlichen Bedarf in der Zukunft zu antizipie-ren. Die Einflussfaktoren können vielfältig sein, beispielsweise makroökonomische Ent-wicklung, das Verhalten von Wettbewerbern oder technologische Entwicklungen. Selbst wenn alle Einflussfaktoren bekannt sind, sind die Zusammenhänge und Wechselwirkun-gen häufig nur schwer zu quantifizieren. Diese Dissertation trägt dazu bei, die Genauigkeit von Bedarfsprognosen zu verbessern. Im ersten Teil der Arbeit wird im Rahmen einer überfassenden Übersicht über das gesamte Spektrum der Anwendungsfelder von Bedarfsprognosen ein neuartiger Ansatz eingeführt, wie Studien zu Bedarfsprognosen systematisch verglichen werden können und am Bei-spiel von 116 aktuellen Studien angewandt. Die Vergleichbarkeit von Studien zu verbes-sern ist ein wesentlicher Beitrag zur aktuellen Forschung. Denn anders als bspw. in der Medizinforschung, gibt es für Bedarfsprognosen keine wesentlichen vergleichenden quan-titativen Meta-Studien. Der Grund dafür ist, dass empirische Studien für Bedarfsprognosen keine vereinheitlichte Beschreibung nutzen, um ihre Daten, Verfahren und Ergebnisse zu beschreiben. Wenn Studien hingegen durch systematische Beschreibung direkt miteinan-der verglichen werden können, ermöglicht das anderen Forschern besser zu analysieren, wie sich Variationen in Ansätzen auf die Prognosegüte auswirken – ohne die aufwändige Notwendigkeit, empirische Experimente erneut durchzuführen, die bereits in Studien beschrieben wurden. Diese Arbeit führt erstmals eine solche Systematik zur Beschreibung ein. Der weitere Teil dieser Arbeit behandelt Prognoseverfahren für intermittierende Zeitreihen, also Zeitreihen mit wesentlichem Anteil von Bedarfen gleich Null. Diese Art der Zeitreihen erfüllen die Anforderungen an Stetigkeit der meisten Prognoseverfahren nicht, weshalb gängige Verfahren häufig ungenügende Prognosegüte erreichen. Gleichwohl ist die Rele-vanz intermittierender Zeitreihen hoch – insbesondere Ersatzteile weisen dieses Bedarfs-muster typischerweise auf. Zunächst zeigt diese Arbeit in drei Studien auf, dass auch die getesteten Stand-der-Technik Machine Learning Ansätze bei einigen bekannten Datensät-zen keine generelle Verbesserung herbeiführen. Als wesentlichen Beitrag zur Forschung zeigt diese Arbeit im Weiteren ein neuartiges Verfahren auf: Der Similarity-based Time Series Forecasting (STSF) Ansatz nutzt ein Aggregation-Disaggregationsverfahren basie-rend auf einer selbst erzeugten Hierarchie statistischer Eigenschaften der Zeitreihen. In Zusammenhang mit dem STSF Ansatz können alle verfügbaren Prognosealgorithmen eingesetzt werden – durch die Aggregation wird die Stetigkeitsbedingung erfüllt. In Expe-rimenten an insgesamt sieben öffentlich bekannten Datensätzen und einem proprietären Datensatz zeigt die Arbeit auf, dass die Prognosegüte (gemessen anhand des Root Mean Square Error RMSE) statistisch signifikant um 1-5% im Schnitt gegenüber dem gleichen Verfahren ohne Einsatz von STSF verbessert werden kann. Somit führt das Verfahren eine wesentliche Verbesserung der Prognosegüte herbei. Zusammengefasst trägt diese Dissertation zum aktuellen Stand der Forschung durch die zuvor genannten Verfahren wesentlich bei. Das vorgeschlagene Verfahren zur Standardi-sierung empirischer Studien beschleunigt den Fortschritt der Forschung, da sie verglei-chende Studien ermöglicht. Und mit dem STSF Verfahren steht ein Ansatz bereit, der zuverlässig die Prognosegüte verbessert, und dabei flexibel mit verschiedenen Arten von Prognosealgorithmen einsetzbar ist. Nach dem Erkenntnisstand der umfassenden Literatur-recherche sind keine vergleichbaren Ansätze bislang beschrieben worden

    Feasibility of a human performance model in consequence management

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    Human civilization has always encountered unpredictable disasters as a result of natural events. Now it also faces the disasters caused by terrorist attacks. Governments must have consequence management plans in place to protect public health and safety, restore essential services, and provide emergency relief to affected businesses and individuals. Human performance models predict outcomes in complex dynamic situations. Such models can simulate disaster management procedures under varying circumstances. This work applies human performance modeling in a terrorist situation and evaluates possible uses of such models by first responders in practical consequence management applications. It includes a case study of an attempted terrorist attack --Abstract, page iv
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