University of Paderborn

About: University of Paderborn is a education organization based out in Paderborn, Nordrhein-Westfalen, Germany. It is known for research contribution in the topics: Control reconfiguration & Software. The organization has 6684 authors who have published 16929 publications receiving 323154 citations.

Incorporating diversity in active learning with support vector machines

Abstract: In many real world applications, active selection of training examples can significantly reduce the number of labelled training examples to learn a classification function. Different strategies in the field of support vector machines have been proposed that iteratively select a single new example from a set of unlabelled examples, query the corresponding class label and then perform retraining of the current classifier. However, to reduce computational time for training, it might be necessary to select batches of new training examples instead of single examples. Strategies for single examples can be extended straightforwardly to select batches by choosing the h > 1 examples that get the highest values for the individual selection criterion. We present a new approach that is especially designed to construct batches and incorporates a diversity measure. It has low computational requirements making it feasible for large scale problems with several thousands of examples. Experimental results indicate that this approach provides a faster method to attain a level of generalization accuracy in terms of the number of labelled examples.

Atomistic simulations of complex materials: ground-state and excited-state properties

Abstract: The present status of development of the density-functional-based tightbinding (DFTB) method is reviewed. As a two-centre approach to densityfunctional theory (DFT), it combines computational efficiency with reliability and transferability. Utilizing a minimal-basis representation of Kohn–Sham eigenstates and a superposition of optimized neutral-atom potentials and related charge densities for constructing the effective many-atom potential, all integrals are calculated within DFT. Self-consistency is included at the level of Mulliken charges rather than by self-consistently iterating electronic spin densities and effective potentials. Excited-state properties are accessible within the linear response approach to time-dependent (TD) DFT. The coupling of electronic and ionic degrees of freedom further allows us to follow the non-adiabatic structure evolution via coupled electron–ion molecular dynamics in energetic particle collisions and in the presence of ultrashort intense laser pulses. We either briefly outline or give references describing examples of applications to ground-state and excited-state properties. Addressing the scaling problems in size and time generally and for biomolecular systems in particular, we describe the implementation of the parallel ‘divide-and-conquer’ order-N method with DFTB and the coupling of the DFTB approach as a quantum method with molecular mechanics force fields.

A virtual network mapping algorithm based on subgraph isomorphism detection

Abstract: Assigning the resources of a virtual network to the components of a physical network, called Virtual Network Mapping, plays a central role in network virtualization. Existing approaches use classical heuristics like simulated annealing or attempt a two stage solution by solving the node mapping in a first stage and doing the link mapping in a second stage.The contribution of this paper is a Virtual Network Mapping (VNM) algorithm based on subgraph isomorphism detection: it maps nodes and links during the same stage. Our experimental evaluations show that this method results in better mappings and is faster than the two stage approach, especially for large virtual networks with high resource consumption which are hard to map.

Service Orientation of a Retailer’s Business Strategy: Dimensions, Antecedents, and Performance Outcomes

Abstract: Augmenting products with services is a major way retailers have of gaining differentiation in today’s competitive market. Despite its importance, this topic has received relatively little research attention. Unlike previous research, this study adopts a more comprehensive perspective on retail services by examining three important research gaps related to a service-oriented business strategy: First, the authors elaborate on the dimensions of a service-oriented business strategy and introduce a new measure of this strategy. Second, the authors examine the antecedents of a service-oriented business strategy. In practice, there appears to be considerable variability in terms of the extent to which retailers demonstrate a service orientation, but there is a major gap in the understanding of what factors influence this orientation. Third, the authors investigate the neglected link between a service-oriented business strategy and performance outcomes. To examine these three important areas, the authors...

Mapping the institutional capital of high-tech firms: A fuzzy-set analysis of capitalist variety and export performance

Abstract: We examine how institutional configurations, not single institutions, provide companies with institutional capital. Building on the varieties-of-capitalism approach, it is argued that competitive advantage in high-tech industries with radical innovation may be supported by combinations of certain institutional conditions: lax employment protection, weak collective bargaining coverage, extensive university training, little occupational training, and a large stock market. Furthermore, multinational enterprises engage in “institutional arbitrage”: they allocate their activities so as to benefit from available institutional capital. These hypotheses are tested on country-level data for 19 OECD economies in the period 1990 to 2003. A fuzzy-set qualitative comparative analysis yields several interesting findings. A high share of university graduates and a large stock market are complementary institutions leading to strong export performance in high-tech. Employment protection is neither conducive nor harmful to export performance in high-tech. A high volume of cross-border mergers and acquisitions, as a form of institutional arbitrage leading to knowledge flows, acts as a functional equivalent to institutions that support knowledge production in the home economy. Implications of these findings for theory, policy, and the analysis of firm-level behavior are developed.