Johannes Kepler University of Linz

About: Johannes Kepler University of Linz is a education organization based out in Linz, Oberösterreich, Austria. It is known for research contribution in the topics: Thin film & Quantum dot. The organization has 6605 authors who have published 19243 publications receiving 385667 citations.

An integrated approach of flood risk assessment in the eastern part of Dhaka City

Abstract: The flood risk is a function of the flood hazard, the exposed values, and their vulnerability In addition to extreme hydrological events, different anthropogenic activities such as extensive urbanization and land use play an important role in producing catastrophic floods Considerations of both physical and social dimensions are therefore equally important in flood risk assessment However, very often the risk assessment studies focus either on physical or social dimensions In addition, the available studies often focus on economic valuation of only direct tangible costs In this study, we provide an integrated flood risk assessment approach that goes beyond the valuation of direct tangible costs, through incorporating physical dimensions in hazard and exposure and social dimensions in vulnerability The method has been implemented in the Dhaka City, Bangladesh, an area internationally recognized as hot spot for flood risk In this study, flood hazards for different return periods are calculated in spatial environment using a hydrologic model, HEC-RAS Vulnerability is assessed through aggregation of various social dimensions, ie, coping and adaptive capacities, and susceptibility We assess vulnerability for both baseline and improved scenarios In the baseline scenario, current early warning for study area is considered In the alternative scenario, the warning system is expected to improve Aggregating hazard, exposure and vulnerability, risk maps (in terms of both tangible and intangible costs) of several return period floods are produced for both baseline and improved scenarios Compared to traditional assessments, the integrated assessment approach used in this study generates more information about the flood risk Consequently, the results are useful in evaluating policy alternatives and minimizing property loss in the study area

Crystallinity and mechanical properties of PP-homopolymers as influenced by molecular structure and nucleation

Abstract: The evolution of crystallinity and mechanical properties of two different series of PP-homopolymers (RE grades coming directly from the polymerization reactor and CR grades priorly subjected to a defined degradation process) as influenced by the molar mass and heterogeneous nucleation was investigated, including one highly isotactic material to check the tacticity influence. In principle, the effects seem explainable by differences in the number of nuclei and the spherulithic growth speed, which were determined separately. The nucleation effects are similar for all materials, but strongly dependent of the molar mass of the materials. Apart from the bulk material properties, also the development of shearinduced structures is strongly influenced by molar mass and nucleation, contributing additionally to mechanics. © 1996 John Wiley & Sons, Inc.

Non-iterative direct data-driven controller tuning for multivariable systems: theory and application

Abstract: In this study, a data-driven technique is proposed to deal with multivariable fixed-order controller design. The method is based on the virtual reference feedback tuning (VRFT) philosophy and thus does not require any model of the plant. Unlike standard VRFT for SISO systems, extended instrumental variables and variance weighting are used to counteract the effect of noise and achieve consistent controller estimate with a single set of input-output data. The proposed strategy is numerically compared to other existing direct and indirect techniques on a benchmark simulation example. The effectiveness of the method is finally tested on the airpath control of a real diesel engine.

Investigating the defect detection effectiveness and cost benefit of nominal inspection teams

Abstract: Inspection is an effective but also expensive quality assurance activity to find defects early during software development. The defect detection process, team size, and staff hours invested can have a considerable impact on the defect detection effectiveness and cost-benefit of an inspection. In this paper, we use empirical data and a probabilistic model to estimate this impact for nominal (noncommunicating) inspection teams in an experiment context. Further, the analysis investigates how cutting off the inspection after a certain time frame would influence inspection performance. Main findings of the investigation are: 1) Using combinations of different reading techniques in a team is considerably more effective than using the best single technique only (regardless of the observed level of effort). 2) For optimizing the inspection performance, determining the optimal process mix in a team is more important than adding an inspector (above a certain team size) in our model. 3) A high level of defect detection effectiveness is much more costly to achieve than a moderate level since the average cost for the defects found by the inspector last added to a team increases more than linearly with growing effort investment. The work provides an initial baseline of inspection performance with regard to process diversity and effort in inspection teams. We encourage further studies on the topic of time usage with defect detection techniques and its effect on inspection effectiveness in a variety of inspection contexts to support inspection planning with limited resources.

Line-of-Sight Spatial Modulation for Indoor mmWave Communication at 60 GHz

Abstract: In this paper, we propose to use spatial modulation (SM) and the generalized spatial modulation (GSM) MIMO schemes in indoor line-of-sight (LOS) millimeter-wave (mmWave) communication at 60GHz. SM/GSM are known but only at low-GHz frequencies where the channels are typically rich scattered and characterized by Rayleigh or Rician distribution. However, 60-GHz indoor channels are typically not rich but rather sparsely scattered and dominated by the LOS component, thus making them different from low-GHz fading channels and our work novel. We first seek to optimize SM in LOS by finding the channel conditions that minimize its symbol error probability (SEP). Then, we extend our studies to LOS GSM and derive its channel capacity and SEP. Furthermore, we present numerical studies on the behavior and performance of SM/GSM in LOS. LOS spatial multiplexing and beamforming MIMO schemes are used as benchmarks for comparison. At last, we propose novel TX and RX hardware architectures, both of which use only a single RF chain, for implementation of SM/GSM at mmWave frequencies. Both simplicity and good performance are exhibited by LOS SM/GSM thus making them very attractive techniques for short-range indoor mmWave communications at 60GHz.