Landslide hazard and risk analyses at a landslide prone catchment area using statistical based geospatial model

This paper presents the application of remote sensing techniques, digital image analysis and Geographic Information System tools to delineate the degree of landslide hazard and risk areas in the Balik Pulau area in Penang Island, Malaysia. Its causes were analysed through various thematic attribute data layers for the study area. Firstly, landslide locations were identified in the study area from the interpretation of aerial photographs, satellite imageries, field surveys, reports and previous landslide inventories. Topographic, geologic, soil and satellite images were collected and processed using Geographic Information System and image processing tools. There are 12 landslide-inducing parameters considered for the landslide hazard analyses. These parameters are: topographic slope, topographic aspect, plan curvature, distance to drainage and distance to roads, all derived from the topographic database; geology and distance to faults, derived from the geological database; landuse/landcover, derived from Landsat satellite images; soil, derived from the soil database; precipitation amount, derived from the rainfall database; and the vegetation index value, derived from SPOT satellite images. In addition, hazard analyses were performed using landslide-occurrence factors with the aid of a statistically based frequency ratio model. Further, landslide risk analysis was carried out using hazard map and socio-economic factors using a geospatial model. This landslide risk map could be used to estimate the risk to population, property and existing infrastructure like transportation networks. Finally, to check the accuracy of the success-rate prediction, the hazard map was validated using the area under curve method. The prediction accuracy of the hazard map was 89%. Based on these results the authors conclude that frequency ratio models can be used to mitigate hazards related to landslides and can aid in land-use planning.     

Lagrange stability and performance analysis of discrete-time piecewise affine systems with logic states

In this paper we consider discrete-time piecewise affine systems with boolean inputs, outputs and states and show that they can be represented in a logic canonical form where the logic variables influence the switching between different submodels but not the continuous-valued dynamics. We exploit this representation for studying Lagrange stability and developing performance analysis procedures based on linear matrix inequalities. Moreover, by using arguments from dissipativity theory for non-linear systems, we generalize our approach to solve the H _∞ analysis problem.     

Highly interactive computational steering for coupled 3D flow problems utilizing multiple GPUs

Most computational fluid dynamics (CFD) simulations require massive computational power which is usually provided by traditional High Performance Computing (HPC) environments. Although interactivity of the simulation process is highly appreciated by scientists and engineers, due to limitations of typical HPC environments, present CFD simulations are usually executed non interactively. A recent trend is to harness the parallel computational power of graphics processing units (GPUs) for general purpose applications. As an alternative to traditional massively parallel computing, GPU computing has also gained popularity in the CFD community, especially for its application to the lattice Boltzmann method (LBM). For instance, Tölke and others presented very efficient implementations of the LBM for 2D as well as 3D space (Toelke J, in Comput Visual Sci. (2008); Toelke J and Krafczk M, in Int J Comput Fluid Dyn 22(7): 443–456 (2008)). In this work we motivate the use of GPU computing to facilitate interactive CFD simulations. In our approach, the simulation is executed on multiple GPUs instead of traditional HPC environments, which allows the integration of the complete simulation process into a single desktop application. To demonstrate the feasibility of our approach, we show a fully bidirectional fluid-structure-interaction for self induced membrane oscillations in a turbulent flow. The efficiency of the approach allows a 3D simulation close to realtime.     

MaDe4IC: an abstract method for managing model dependencies in inter-organizational cooperations

Inter-organizational cooperations are complex in terms of coordination, agreements, and value creation for involved partners. When managing complex cooperations, it is vital to maintain models describing them. Changing one model to regain consistency with the running system might result in new inconsistencies. As a consequence, this maintenance phase grows in complexity with increasing number of models. In this context, challenges are to ensure consistency at design time and to monitor the system at runtime, i.e., at design time, consistency between different models describing the cooperation needs to be ensured. At runtime, behavior of the software system needs to be compared with its underlying models. In this paper, we propose a structured and model-independent method that supports ensuring and maintaining consistency between running system and underlying models for inter-organizational cooperations.     

Bruchmechanische Untersuchungen und Rißfortschrittsmessungen an lunkerbehafteten,bauteilähnlichen Proben aus GK-AlSi12

Fracture Mechanics Investigations on Cast Aluminium Aluminium castings cannot be massproduced economically without casting pores or similar flaws. These flaws must, however, be avoided, at least in the highly stressed regions of cast safety components of automobiles by changes in design or casting procedure. In other regions flaws up to a certain size can be tolerated if it can be shown by calculation and experiment that cracks either will not propagate from these flaws or at least will not reach critical size during the life of the component. Cast aluminium wheels are an example of such a component. Their allowable flaw sizes were determined in the following way:

• The stresses occuring in service wer measured in 17 locations in a test rig in the laboratory and on a race track.
• The crack propagation characteristics and the ΔK_th-values of the cast aluminium material were determined.
• Crack propagation was calculated under the stresses measured in service; based on these measured stresses and the fracture mechanics characteristics, locations were selected in the cast aluminium wheel where no flaws can be allowed; in other locations with lower stresses the allowable flaw sizes were calculated with a large safety factor.

     

Some results on the Collatz problem

The paper refers to the Collatz's conjecture. In the first part, we present some equivalent forms of this conjecture and a slight generalization of a former result from [1]. Then, we present the notion of “chain subtrees” in Collatz's tree followed by a characterization theorem and some subclass of numbers which are labels for some chain subtrees. Next, we define the notion of “fixed points” and using this, we give another conjecture similar to Collatz's conjecture. Some new infinite sets of numbers for which the Collatz's conjecture holds are given. Finally, we present some interesting results related to the number of “even” and “odd” branches in the Collatz's tree. Received: 15 September 1999 / 2 June 2000     

The behaviour of styrenes p-substituted with a liquid crystalline side group under anionic polymerization conditions

Summary The synthesis of p-alkyloxymethylstyrenes and p-alkyloxystyrenes with 4,4-disubstituted-biphenyl or 2,5-disubstituted-1,3-dioxane groups as side chains are described. The phase behaviour of both the monomers and polymers obtained by free radical polymerizations is investigated.The monomers are not suitable for living anionic polymerizations because of the side reactions which occur as competitive reactions to the normal chain growth. The benzylic ether group of the alkyloxymethylstyrene was splited under the influence of the anionic centres. A metalation of the phenyl ring of the styryl group was observed for alkyloxystyrenes.     

Food Exploitation in Termites: Indication for a General Feeding-Stimulating Signal in Labial Gland Secretion of Isoptera

The paired labial glands are located in all termite species in the thorax. During food exploitation workers of the French termite Reticulitermes santonensis and the African termite Schedorhinotermes lamanianus release the secretion of their labial glands directly onto the food. The secretion carries a water-soluble, heat-resistant, nonvolatile signal that stimulates gnawing and feeding and leads to aggregations of feeding workers. In a feeding bioassay, extracts of the labial glands of 11 termite species from five families all proved to have this feeding-stimulating effect both on R. santonensis and S. lamanianus. The heat resistance of the feeding-stimulating signal also could be shown for selected species from all termite families tested. A combined thin layer chromatography–feeding bioassay on cellulose TLC plates showed that after chromatography of labial gland secretion, the feeding-stimulating signal is located in all 11 species in the same area from R_f 0.46 to 0.88. An extract of labial glands of cockroaches stimulated feeding in R. santonensis and S. lamanianus as well, but was not active after heat treatment and after TLC. This points towards a general feeding-stimulating signal having evolved only in the labial gland secretion of termites.     

Lower bounds for sorting on mesh-connected architectures

Summary Lower bounds for sorting on mesh-connected arrays of processors are presented. For sorting N=n₁ n ₂...n _r elements on an n ₁×n₂×... ×n _r array 2(n ₁+...+n _r–1)+n _r data interchange steps are needed asymptotically. For two dimensions these bounds are asymptotically best possible provided that n ₁ and n ₂ are powers of 2. In this case the generalized s ²-way merge sort of Thompson and Kung turns out to be asymptotically optimal. The minimal asymptotic bound of 2 2N interchange steps can be obtained only by sorting algorithms suitable for N/2×2N meshes. For r3 dimensions an analysis of aspect-ratios also demonstrates that there exist mesh-connected architectures which are better suited for sorting than simple r-dimensional cubes.This work was done at the Institut für Informatik und Praktische Mathematik, University of Kiel, Federal Republic of Germany