Professor Dr. Walter Semmler: A German Mine Water Pioneer

Prof. Dr. Walter Semmler (1903–1990) was a ground-breaking German hydrogeologist who conducted practical mine water research in Germany, mainly related to dewatering, but also on tracer tests and potential environmental impacts of mine water. In addition, his contributions to professional associations in Germany and the formation of water authorities in the Ruhr Coal Mining District was noteworthy.     

A feasible directions method for nonsmooth convex optimization

We propose a new technique for minimization of convex functions not necessarily smooth. Our approach employs an equivalent constrained optimization problem and approximated linear programs obtained with cutting planes. At each iteration a search direction and a step length are computed. If the step length is considered “non serious”, a cutting plane is added and a new search direction is computed. This procedure is repeated until a “serious” step is obtained. When this happens, the search direction is a feasible descent direction of the constrained equivalent problem. To compute the search directions we employ the same formulation as in FDIPA, the Feasible Directions Interior Point Algorithm for constrained optimization. We prove global convergence of the present method. A set of numerical tests is described. The present technique was also successfully applied to the topology optimization of robust trusses. Our results are comparable to those obtained with other well known established methods.     

Structural invariance and age-related performance differences in face cognition.

Perceiving and memorizing faces swiftly and correctly are important social competencies. The organization of these interpersonal abilities and how they change across the life span are still poorly understood. We investigated changes in the mean and covariance structure of face cognition abilities across the adult life span. A sample of 448 participants, with age ranging from 18 to 88 years, completed a battery of 15 face cognition tasks. After establishing a measurement model of face cognition that distinguishes between face perception, face memory, and the speed of face cognition, we used multiple group models and age-weighted measurement models to explore age-related changes. The modeling showed that the loadings and intercepts of all measures are age invariant. The factor means showed substantial decrements with increasing age. Age-related decrements in performance were strongest for the speed of face cognition but were also salient for face perception and face memory. The onset of age decrements is apparent in the 60s for face perception, in the late 40s for face memory, and in the early 30s for speed of face cognition. Implications of these findings on a theoretical and methodological level are discussed, and potential consequences for applied settings are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

ON MACHINE VISION AND CAST

Building machines that “see” is a complex systems engineering task. While, at present, universal vision machines (with performance comparable to the human visual system) appear to be impractical, special purpose machines have been devised successfully to operate in restricted application domains. Designing such a dedicated system usually requires detailed knowledge of the application domain, experience with available processing techniques, and a large experimentation effort. Despite the peculiarities of different vision domains, many of them share similar processing techniques. We propose to develop computerized tools to support the development of application-specific vision systems in order to make this process less time-consuming and costly. We discuss some of the fundamental problems of machine vision and examine why current computer-aided systems theory (CAST) technology is not sufficient for this task. On the other hand it seems likely that developments in the Held of machine vision could have a significant impact upon other CAST applications of similar complexity.     

面向照相手机的小型低成本集成视频放大器

在电视屏幕上显示照片是当今照相手机中一项越来越重要的功能,因为它能让您比以往更令人满意地与朋友及家人一起观看您拍摄的照片.电视输出功能可以相对较少的成本增加至照相手机中,并为手机厂商提供重要的增收机会.     

Steel Desulphurisation and Sulphur Bonding in Solidified Ladle Slags

It was investigated in which form sulphur is bonded in ladle slags. For this purpose, the mineralogical phases of the ladle slags were qualitatively and quantitatively evaluated by means of a microprobe. This slag characterisation allowed reconstructing the bonding of sulphur into the phases of the ladle slag. Moreover, the reaction process with regard to the ionic theory as well as the structural formula for the mechanism of sulphur bonding were discussed. The bonding of sulphur into calcium aluminate slags is determined by the sulphide ion content in the slag as well as by the ratio of (CaO)/(Al₂O₃). Calcium sulphide separates only if the slag contains a large number of sulphide ions. When Ca₁₂Al₁₄O₃₃ is separated the sulphide ion is successively integrated into the lattice. The crystal lattice of Ca₁₂Al₁₄O₃₃ is characterised by an open, three‐dimensional anionic network composed of aluminium‐oxygen tetrahedrons linking the edges. In this network, large interstitial spaces are formed, which may be filled with calcium ions on the one hand and statistically with a free oxygen or sulphide ion on the other hand.