Controlling the Data Warehouse – a Balanced Scorecard Approach

Data warehouse systems have become a basic technological infrastructure in management decision making. Nevertheless, the overall utility of data warehouses remains unmeasured in most practical cases. As a consequence of this, IT-managers do not possess appropriate means to evaluate warehouse benefits in order to decide about investments in warehousing technology. This paper develops a controlling instrument for data warehouse systems based on the Balanced Scorecard (BSC) approach. On the basis of the technological aspects of data warehouse systems, the BSC perspectives are developed and populated with relevant objectives and measures for datawarehouse success. These perspectives are integrated into a consistent data warehouse scorecard. Finally, this instrument provides a holistic approach to drive the performance of data warehouse systems

Time-dependent Monte Carlo continuum radiative transfer

Aims. We present an implementation of an algorithm for 3D time-dependent Monte Carlo radiative transfer. It allows one to simulate temperature distributions as well as images and spectral energy distributions of the scattered light and thermal reemission radiation for variable illuminating and heating sources embedded in dust distributions, such as circumstellar disks and dust shells on time scales up to weeks. Methods. We extended the publicly available 3D Monte Carlo radiative transfer code POLARIS with efficient methods for the simulation of temperature distributions, scattering, and thermal reemission of dust distributions illuminated by temporally variable radiation sources. The influence of the chosen temporal step width and the number of photon packages per time step as key parameters for a given configuration is shown by simulating the temperature distribution in a spherical envelope around an embedded central star. The effect of the optical depth on the temperature simulation is discussed for the spherical envelope as well as for a model of a circumstellar disk with an embedded star. Finally, we present simulations of an outburst of a star surrounded by a circumstellar disk. Results. The presented algorithm for time-dependent 3D continuum Monte Carlo radiative transfer is a valuable basis for preparatory studies as well as for the analysis of continuum observations of the dusty environment around variable sources, such as accreting young stellar objects. In particular, the combined study of light echos in the optical and near-infrared wavelength range and the corresponding time-dependent thermal reemission observables of variable, for example outbursting sources, becomes possible on all involved spatial scales.Comment: Accepted for publication in Astronomy & Astrophysics. 15 pages, 18 figure

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Corresponding Active Orbital Spaces along Chemical Reaction Paths

The accuracy of reaction energy profiles calculated with multi-configurational electronic structure methods and corrected by multi-reference perturbation theory depends crucially on consistent active orbital spaces selected along the reaction path. However, it has been challenging in all but the simplest cases to choose molecular orbitals that can be considered corresponding in different molecular structures. Here, we demonstrate how active orbital spaces can be selected consistently along reaction coordinates in a fully automatized way. The approach requires no structure interpolation between reactants and products. Instead, it emerges from a synergy of an orbital mapping ansatz [J. Chem. Phys. 2019, 150, 214106] combined with our fully automated active space selection algorithm [J. Chem. Theory Comput. 2016, 12, 1760]. The former we extend by including also virtual orbitals rather than occupied ones only. We demonstrate our algorithm for the potential energy profile of the homolytic carbon-carbon bond dissociation and rotation around the double bond of 1-pentene in the electronic ground state. However, our algorithm also applies to electronically excited Born-Oppenheimer surfaces in a straightforward manner.Comment: 16 pages, 4 figure

Strategische Potenziale von Open Source-Software für die computergestützte Hochschullehre (cHL)

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Web Log Mining bei cHL-Anwendungen

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Das Data-Mining-Konzept

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Bildungsbedarfsanalyse auf Grundlage von Stellenanzeigen – Potenziale des Text Mining für das Lern-Service-Engineering

Die extrem kurzen Technologiezyklen in der ICT-Industrie stellen Unternehmen vor das Pro-blem, Mitarbeiter zeit- und themenadäquat weiter zu qualifizieren. Für Bildungsanbieter erwächst damit die Herausforderung, relevante Bildungsthemen möglichst frühzeitig zu identifizieren, ökonomisch zu bewerten und ausgewählte Themen in Form geeigneter Leistungsangebote zur Marktreife zu bringen. Zur Entscheidungsunterstützung der Identifikationsphase wird in diesem Beitrag das bedarfsanalytische Instrument der Stellenanzeigenauswertung aufgegriffen und dessen Umsetzung mithilfe von Methoden des Text Mining exemplarisch demonstriert. Abschließend wird die Integration dieses Instruments mit dem Lern-Service-Engineering thema-tisiert und weiterführender Forschungsbedarf identifiziert