A comparison of two sampling methods for global sensitivity analysis

We compare the convergence properties of two different quasi-random sampling designs – Sobol?s quasi-Monte Carlo, and Latin supercube sampling in variance-based global sensitivity analysis. We use the non-monotonic V-function of Sobol? as base case-study, and compare the performance of both sampling strategies at increasing sample size and dimensionality against analytical values. The results indicate that in almost all cases investigated here, the Sobol? design performs better. This, coupled with the fact that effective Latin supercube sampling requires a priori knowledge of the interaction properties of the function, leads us to recommend Sobol? sampling in most practical cases.     

The effect of physical aging on the embrittlement of steam-sterilized polycarbonate

Polycarbonate is known to suffer from dramatic reductions in ductility upon exposure to hot, humid environments, such as during steam sterilization. Two phenomena have been proposed to be the main causes of this embrittlement: hydrolysis and microcavity formation. The present study focuses on a third phenomenon, whose contribution to the embrittlement has until now been considered insignificant: (physical) aging. By studying the influence of steam sterilization on the tensile deformation behavior of polycarbonate, it is shown that aging actually is one of the dominant factors in the embrittlement.     

Ester-functionalized poly(3-alkylthiophene) copolymers: Synthesis,physicochemical characterization and performance in bulk heterojunction organic solar cells

The introduction of functional moieties in the donor polymer (side chains) offers a potential pathway toward selective modification of the nanomorphology of conjugated polymer:fullerene active layer blends applied in bulk heterojunction organic photovoltaics, pursuing morphology control and solar cell stability. For this purpose, two types of poly(3-alkylthiophene) random copolymers, incorporating different amounts (10/30/50%) of ester-functionalized side chains, were efficiently synthesized using the Rieke method. The solar cell performance of the functionalized copolymers was evaluated and compared to the pristine P3HT:PCBM system. It was observed that the physicochemical and opto-electronic characteristics of the polythiophene donor material can be modified to a certain extent via copolymerization without (too much) jeopardizing the OPV efficiency, as far as the functionalized side chains are introduced in a moderate ratio (<30%) and that preference is given to side chains with a small molar volume. A range of complementary techniques – UV–Vis spectroscopy, (modulated temperature) differential scanning calorimetry, transmission electron microscopy and X-ray diffraction analysis – indicated that variations in polymer crystallinity, while maintaining a high level of regioregularity, are probably the main factor responsible for the observed differences.     

Characteristics and Modification of Non-metallic Inclusions in Titanium-Stabilized AISI 409 Ferritic Stainless Steel

This study describes an investigation into the improvement of castability, final surface quality and formability of titanium-stabilized AISI 409 ferritic stainless steel on an industrial scale. Non-metallic inclusions found in this industrially produced stainless steel were first characterized using SEM-EDS analyses through the INCA-Steel software platform. Inclusions were found to consist of a MgO·Al₂O₃ spinel core, which acted as heterogeneous nucleation site for titanium solubility products. Plant-scale experiments were conducted to either prevent the formation of spinel, or to modify it by calcium treatment. Modification to spherical dual-phase spinel-liquid matrix inclusions was achieved with calcium addition, which eliminated submerged entry nozzle clogging for this grade. Complete modification to homogeneous liquid calcium aluminates was achieved at high levels of dissolved aluminum. A mechanism was suggested to explain the extent of modification achieved.     

穿越黑色时空的光影世界——间离剧

正一家在上海创办的建筑与室内设计事务所,致力于根据客户的需求制定美观新颖的空间解决方案。我们对概念的艺术性和施工的工艺同样重视。每个项目都根据其环境和条件量身定做,并在有限的造价和时间里做出最好的效果。来到这个剧院的观众,都是自己这出戏的演员和导演。间离剧以独特的形态,为观众提供了别具一格     

Application of energy efficient soft-decision error control in wireless sensor networks

Energy efficient reliable communication over an unpredictable wireless medium is a major challenge for resource constrained wireless sensor nodes in process/environment control application. In this paper, we propose a Soft Decision Decoding (SDD) based advanced Forward Error Correction (FEC) scheme for low power distributed sensor nodes. The proposed BCH (Bose-Chaudhuri-Hocquenghem) based adaptive Chase-2 decoding scheme offers attractive energy benefits as compared to Hard Decision Decoding (HDD). The reduced decoding complexity is obtained by limiting the codeword search space and fewer algebraic operations compared to standard Chase-2. A realistic environmental scenario incorporating path loss, Rayleigh fading and Additive White Gaussian Noise has been considered to investigate the performance of the proposed scheme. A detailed comparison is carried out with HDD of BCH codes using the widely known Crossbow MicaZ node parameters. The simulation results indicate that for low power WSN, the proposed SDD based adaptive scheme offers better tradeoff between energy and reliability than HDD schemes.     

Innovation Subsidies: Does the Funding Source Matter for Innovation Intensity and Performance? Empirical Evidence from Germany

In this paper we analyze the effect of European and national funding on innovation input and output at the firm level. In terms of innovation input, we do not find evidence that one policy crowds out the effect of the other. Instead, the policies are complements. In terms of output, we find that subsidy recipients are more active with respect to patenting. A citation analysis of patents reveals that the subsidy recipients file patents that are more valuable (in terms of forward citations) than those filed in the counterfactual situation of receiving no public support. These results suggest that public funding triggers socially beneficial research projects and that the co-existence of national and European policies does not lead to crowding-out effects when compared to a hypothetical world of a closed economy with no supplemental European policies.     

Modellbasierte Entscheidungsunterstützung in Produktions- und Dienstleistungsnetzwerken

In this paper, we sketch some of the challenges that should be addressed in future research efforts for model-based decision support in manufacturing and service networks. This includes integration issues, taking into account the autonomy of the decision-making entities in face of information asymmetry, the modeling of preferences of the decision-makers, efficiently determining robust solutions, i.e. solutions that are insensitive with respect to changes in the problem data, and a reduction of the time needed for model building and usage. The problem solution cycle includes problem analysis, the design of appropriate algorithms and their performance assessment. We are interested in a prototypical integration of the proposed methods within application systems, which can be followed up with field tests of the extended application systems. We argue that the described research agenda requires the interdisciplinary collaboration of business and information systems engineering researchers with colleagues from management science, computer science, and operations research. In addition, we present some exemplifying, illustrative examples of relevant research results.