12 research outputs found

    A Detailed Study on Aggregation Methods used in Natural Language Interface to Databases (NLIDB)

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    Historically, databases have been the most crucial issue in the study of information systems, and they constitute an essential part of all information management systems. Since, it complicated due to restricting the number of potential users, particularly non-expert database users who must comprehend the database structure to submit such queries. Natural language interface (NLI), the simplest method to retrieve information, is one possibility for interacting with the database. The transformation of a natural language query into a Structured Query (SQL) in a database is known as a "Natural Language Interface to Database" (NLIDB). This study uses NLIDB to handle the works performed under various aggregations with aggregation functions, a grouping phrase, and a possessing clause. This study carefully examines the numerous systematic aggregation approaches utilized in the NLIDB. This review provides extensive information about the many methods, including query-based, pattern-based, general, keyword-based NLIDB, and grammar-based systems, to extract data for a dissertation from a generic module for use in such systems that support query execution utilizing aggregations

    Spatial patterns and indices for heat waves and droughts over Europe using a decomposition of extremal dependency

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    We present a method for the analysis and compact description of large-scale multivariate weather extremes. Spatial patterns of extreme events are identified using the tail pairwise dependence matrix (TPDM) proposed by Cooley and Thibaud (2019). We also introduce the cross-TPDM to identify patterns of common extremes in two variables. An extremal pattern index (EPI) is developed to provide a pattern-based aggregation of temperature. A heat wave definition based on EPI is able to detect the most important heat waves over Europe. As an extension for considering simultaneous extremes in two variables, we propose the threshold-based EPI (TEPI) that captures the compound character of spatial extremes. We investigate daily temperature maxima and precipitation deficits at different accumulation times and find evidence that preceding precipitation deficits have a significant influence on the development of heat waves and that heat waves often co-occur with short-term drought conditions. We exemplarily show for the European heat waves of 2003 and 2010 that TEPI is suitable for describing the large-scale compound character of heat waves.</p

    QUALITY OF PROCESS ? A BUSINESS PROCESS PERSPECTIVE ON QUALITY OF SERVICE

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    The fundamental paradigm shift from a product- to a service-oriented economy implies novel technical and organizational challenges. The resulting dynamic of the technical infrastructure and the increasing development towards requesting external business services to be integrated into end-to-end business processes requires mechanisms ensuring the reliability of the organization?s composed services, workflows and business processes. From a business perspective, QoS characteristics defined based on technical services within the infrastructural layer have to be aggregated to more business-relevant Key Performance Indicators on business process layer to express the Quality of Process. These KPIs represent quality that is highly related to the business?s performance (e.g. processing time of a business service) and are crucial for achieving predefined goals in order to stay competitive in the market. The contribution of this paper is threefold: We (i) provide an in-depth requirements analysis for such a holistic quality management framework, we (ii) develop a holistic aggregation framework which enables service level aggregation incorporating the loosely coupled structure of business processes with invoked systems and services in an instance based manner. To demonstrate the expressive power of our framework we (iii) provide an exemplary industrial application scenario and illustrate the functioning and interplay of the designed artifacts

    Using Domain Ontology for Service Replacement Tasks: An Empirical Evaluation

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    Organizations increasingly use information technology (IT) to integrate their business processes into the processes of their suppliers, customers, and other third parties. An important IT approach is the realization of composite services that organize elementary software services under a shared workflow. Any failure of an elementary service can severely impact the process. The failed service must be examined and, ultimately, be replaced. In solving that task, the process designer must consider the quality-of-service (QoS) of the process. However, the heterogeneity of service descriptions puts the burden on the designer. This research empirically evaluates how designers can use a domain ontology, namely the QoS aggregation ontology, for the replacement task. We report on a laboratory experiment to compare the effectiveness and efficiency of using the ontology vis-à-vis an aggregation table. The results provide evidence for the usefulness of the domain ontology that specifies problem-solving knowledge required for a time-critical task

    Serviceorientiertes Text Mining am Beispiel von Entitätsextrahierenden Diensten

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    Der Großteil des geschäftsrelevanten Wissens liegt heute als unstrukturierte Information in Form von Textdaten auf Internetseiten, in Office-Dokumenten oder Foreneinträgen vor. Zur Extraktion und Verwertung dieser unstrukturierten Informationen wurde eine Vielzahl von Text-Mining-Lösungen entwickelt. Viele dieser Systeme wurden in der jüngeren Vergangenheit als Webdienste zugänglich gemacht, um die Verwertung und Integration zu vereinfachen. Die Kombination verschiedener solcher Text-Mining-Dienste zur Lösung konkreter Extraktionsaufgaben erscheint vielversprechend, da so bestehende Stärken ausgenutzt, Schwächen der Systeme minimiert werden können und die Nutzung von Text-Mining-Lösungen vereinfacht werden kann. Die vorliegende Arbeit adressiert die flexible Kombination von Text-Mining-Diensten in einem serviceorientierten System und erweitert den Stand der Technik um gezielte Methoden zur Auswahl der Text-Mining-Dienste, zur Aggregation der Ergebnisse und zur Abbildung der eingesetzten Klassifikationsschemata. Zunächst wird die derzeit existierende Dienstlandschaft analysiert und aufbauend darauf eine Ontologie zur funktionalen Beschreibung der Dienste bereitgestellt, so dass die funktionsgesteuerte Auswahl und Kombination der Text-Mining-Dienste ermöglicht wird. Des Weiteren werden am Beispiel entitätsextrahierender Dienste Algorithmen zur qualitätssteigernden Kombination von Extraktionsergebnissen erarbeitet und umfangreich evaluiert. Die Arbeit wird durch zusätzliche Abbildungs- und Integrationsprozesse ergänzt, die eine Anwendbarkeit auch in heterogenen Dienstlandschaften, bei denen unterschiedliche Klassifikationsschemata zum Einsatz kommen, gewährleisten. Zudem werden Möglichkeiten der Übertragbarkeit auf andere Text-Mining-Methoden erörtert

    Value- and debt-aware selection and composition in cloud-based service-oriented architectures using real options

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    This thesis presents a novel model for service selection and composition in Cloud-based Service-Oriented Architectures (CB-SOA), which is called CloudMTD, using real options, Dependency Structure Matrix (DSM) and propagation-cost metrics. CB-SOA architectures are composed of web services, which are leased or bought off the cloud marketplace. CB-SOA can improve its utility and add value to its composition by substituting its constituent services. The substitution decisions may introduce technical debt, which needs to be managed. The thesis defines the concept of technical debt for CB-SOA and reports on the available technical debt definitions and approaches in the literature. The formulation of service substitution problem and its technical debt valuation is based on options, which exploits Binomial Options Analysis. This thesis looks at different option types under uncertainty. This thesis is concerned with some scenarios that may lead to technical debt, which are related to web service selection and composition that has been driven by either a technical or a business objective. In each scenario, we are interested in three decisions (1) keep, (2) substitute or (3) abandon the current service. Each scenario takes into consideration either one or more QoS attribute dimension (e.g. Availability). We address these scenarios from an option-based perspective. Each scenario is linked to a suitable option type. A specific option type depends on the nature of the application, problem to be investigated, and the decision to be taken. In addition, we use Dependency Structure Matrix (DSM) in order to represent dependencies among web services in CB-SOA. We introduce time and complexity sensitive propagation-cost metrics to DSM to solve the problem. In addition, CloudMTD model informs the time-value of the decisions under uncertainty based on behavioral and structural aspects of CB-SOA

    Efficient Pattern-Based Aggregation on Sequence Data

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