Active‐matrix and flexible liquid‐crystal displays with carbon‐nanotube pixel electrodes

Abstract— The necessary processes to use random carbon‐nanotube networks as transparent conductors in twisted‐nematic liquid‐crystal displays have been developed, replacing indium tin oxide. Because the nanotubes are deposited vacuum‐free from suspension, the potential advantages are lower costs for material, equipment, and production. Nanotube networks are also much better suited for flexible displays than the commonly used metal oxides. With the developed processes, the world's first full‐color active‐matrix LCDs as well as directly addressed flexible displays on plastic substrates with carbon‐nanotube pixel electrodes, have been realized.     

YaDiV��an open platform for 3D visualization and?3D?segmentation of medical data

In this work, we present the concept, design and implementation of a new software to visualize and segment 3-dimensional medical data. The main goal was to create a platform that would allow trying out new approaches and ideas while staying independent from hardware and operating system, being especially useful for interdisciplinary research groups. A special focus will be given on fast and interactive volume visualization, and a survey on the use of Virtual Reality (VR) and especially haptic/force feedback in medical applications will be provided.     

An Interpolating Sequent Calculus for Quantifier-Free Presburger Arithmetic

Craig interpolation has become a versatile tool in formal verification, used for instance to generate program assertions that serve as candidates for loop invariants. In this paper, we consider Craig interpolation for quantifier-free Presburger arithmetic (QFPA). Until recently, quantifier elimination was the only available interpolation method for this theory, which is, however, known to be potentially costly and inflexible. We introduce an interpolation approach based on a sequent calculus for QFPA that determines interpolants by annotating the steps of an unsatisfiability proof with partial interpolants. We prove our calculus to be sound and complete. We have extended the Princess theorem prover to generate interpolating proofs, and applied it to a large number of publicly available Presburger arithmetic benchmarks. The results document the robustness and efficiency of our interpolation procedure. Finally, we compare the procedure against alternative interpolation methods, both for QFPA and linear rational arithmetic.     

Interactive volume visualization of general polyhedral grids

This paper presents a novel framework for visualizing volumetric data specified on complex polyhedral grids, without the need to perform any kind of a priori tetrahedralization. These grids are composed of polyhedra that often are non-convex and have an arbitrary number of faces, where the faces can be non-planar with an arbitrary number of vertices. The importance of such grids in state-of-the-art simulation packages is increasing rapidly. We propose a very compact, face-based data structure for representing such meshes for visualization, called two-sided face sequence lists (TSFSL), as well as an algorithm for direct GPU-based ray-casting using this representation. The TSFSL data structure is able to represent the entire mesh topology in a 1D TSFSL data array of face records, which facilitates the use of efficient 1D texture accesses for visualization. In order to scale to large data sizes, we employ a mesh decomposition into bricks that can be handled independently, where each brick is then composed of its own TSFSL array. This bricking enables memory savings and performance improvements for large meshes. We illustrate the feasibility of our approach with real-world application results, by visualizing highly complex polyhedral data from commercial state-of-the-art simulation packages.     

On reference solutions and the sensitivity of the 2D Kelvin–Helmholtz instability problem

Two-dimensional Kelvin–Helmholtz instability problems are popular examples for assessing discretizations for incompressible flows at high Reynolds number. Unfortunately, the results in the literature differ considerably. This paper presents computational studies of a Kelvin–Helmholtz instability problem with high order divergence-free finite element methods. Reference results in several quantities of interest are obtained for three different Reynolds numbers up to the beginning of the final vortex pairing. A mesh-independent prediction of the final pairing is not achieved due to the sensitivity of the considered problem with respect to small perturbations. A theoretical explanation of this sensitivity to small perturbations is provided based on the theory of self-organization of 2D turbulence. Possible sources of perturbations that arise in almost any numerical simulation are discussed.     

Driving on Point Clouds: Motion Planning,Trajectory Optimization,and Terrain Assessment in Generic Nonplanar Environments

We present a practical approach to global motion planning and terrain assessment for ground robots in generic three‐dimensional (3D) environments, including rough outdoor terrain, multilevel facilities, and more complex geometries. Our method computes optimized six‐dimensional trajectories compliant with curvature and continuity constraints directly on unordered point cloud maps, omitting any kind of explicit surface reconstruction, discretization, or topology extraction. We assess terrain geometry and traversability on demand during motion planning, by fitting robot‐sized planar patches to the map and analyzing the local distribution of map points. Our motion planning approach consists of sampling‐based initial trajectory generation, followed by precise local optimization according to a custom cost measure, using a novel, constraint‐aware trajectory optimization paradigm. We embed these methods in a complete autonomous navigation system based on localization and mapping by means of a 3D laser scanner and iterative closest point matching, suitable for both static and dynamic environments. The performance of the planning and terrain assessment algorithms is evaluated in offline experiments using recorded and simulated sensor data. Finally, we present the results of navigation experiments in three different environments—rough outdoor terrain, a two‐level parking garage, and a dynamic environment, demonstrating how the proposed methods enable autonomous navigation in complex 3D terrain.     

Efficient order dependency detection

Order dependencies (ODs) describe a relationship of order between lists of attributes in a relational table. ODs can help to understand the semantics of datasets and the applications producing them. They have applications in the field of query optimization by suggesting query rewrites. Also, the existence of an OD in a table can provide hints on which integrity constraints are valid for the domain of the data at hand. This work is the first to describe the discovery problem for order dependencies in a principled manner by characterizing the search space, developing and proving pruning rules, and presenting the algorithm Order, which finds all order dependencies in a given table. Order traverses the lattice of permutations of attributes in a level-wise bottom-up manner. In a comprehensive evaluation, we show that it is efficient even for various large datasets.     

Automatic analysis of DMA races using model checking and <Emphasis Type="Italic">k</Emphasis>-induction

Modern multicore processors, such as the Cell Broadband Engine, achieve high performance by equipping accelerator cores with small “scratch-pad” memories. The price for increased performance is higher programming complexity – the programmer must manually orchestrate data movement using direct memory access (DMA) operations. Programming using asynchronous DMA operations is error-prone, and DMA races can lead to nondeterministic bugs which are hard to reproduce and fix. We present a method for DMA race analysis in C programs. Our method works by automatically instrumenting a program with assertions modeling the semantics of a memory flow controller. The instrumented program can then be analyzed using state-of-the-art software model checkers. We show that bounded model checking is effective for detecting DMA races in buggy programs. To enable automatic verification of the correctness of instrumented programs, we present a new formulation of k-induction geared towards software, as a proof rule operating on loops. Our techniques are implemented as a tool, Scratch, which we apply to a large set of programs supplied with the IBM Cell SDK, in which we discover a previously unknown bug. Our experimental results indicate that our k-induction method performs extremely well on this problem class. To our knowledge, this marks both the first application of k-induction to software verification, and the first example of software model checking in the context of heterogeneous multicore processors.     

The distribution of housing wealth in 16 European countries: accounting for institutional differences

Housing wealth is the largest source of household wealth, but we know little about the distribution of housing wealth and how institutions have shaped this distribution. Subsidies for homeownership, privatisation of social housing and mortgage finance liberalisation are likely to have influenced the distribution of housing wealth in recent decades. To examine their impact, we describe housing wealth inequalities across occupational classes for two birth cohorts aged fifty and older. The analysis is conducted across 16 European countries with divergent welfare states and housing systems using the fourth wave of the survey of health, ageing and retirement in Europe (SHARE; 2011/2012). Our results indicate that the expansion of homeownership in a market-based housing system is associated with a more unequal distribution of housing wealth across occupational classes, as an increasing number of ‘marginal’ owners are drawn into precarious homeownership. Such a pattern is not found in housing wealth accumulation regimes with a less market-based provision of housing. When the state or the family drive homeownership expansion, a de-coupling of labour market income and housing consumption results in a more equal distribution of housing wealth.     

Effect of different potassium levels in hay on acid–base status and mineral balance in periparturient dairy cows

Forages commonly used in dry cow rations contain high K concentrations. This results in a high dietary cation–anion difference (DCAD), which can compromise the calcium homeostasis of periparturient cows. The aim of this study was to determine the effect of 2 types of hay, fed during the prepartum period and differing in their K concentrations, on the peripartum acid–base status and mineral balance of dairy cows. During the prepartum period, the cows of group K₃₃ (n = 6) received a diet based on hay with a high K concentration (33 g/kg of DM), whereas the cows of group K₁₃ (n = 6) received a diet based on hay with a low K concentration (13 g/kg of DM). Both experimental diets were formulated to be isoenergetic and isonitrogenous. After calving, all cows received the same diet based on hay K₃₃. Blood and urine samples were taken on d 14, 7, and 3 before parturition, at parturition, and then daily during the first 8 d after calving. Concentrations of minerals were analyzed in both blood and urine. Creatinine was also measured in urine for the calculation of the mineral:creatinine ratio. The acid–base parameters in blood (pH and HCO₃⁻ concentration) and urine (pH, net acid–base excretion, and base–acid quotient) were determined on d 14, 7, and 3 before parturition, at parturition, and on d 1 after parturition. The use of hay K₁₃ reduced the DCAD value of the prepartum diet by half (195 vs. 514 mEq/kg of DM). No significant differences between the 2 groups were observed for blood acid–base indicators or plasma minerals except for the Mg plasma concentration, which tended to be higher in group K₁₃ from d 3 prepartum to d 2 after calving. In group K₁₃, urinary Ca excretion tended to be higher from d 3 prepartum to d 1 after parturition than that in group K₃₃. On d 3 before parturition, urinary pH and net acid–base excretion were significantly lower in group K₁₃ than in group K₃₃. On d 14, 7, and 3 before parturition, base–acid quotient was significantly lower in group K₁₃ than in group K₃₃. In group K₁₃, daily feed intake and hence daily intake of Ca, P, and Mg during d 3 and 4 after parturition were higher than in group K₃₃. The decrease of the DCAD in positive ranges by feeding a low-K hay before parturition induced a reduction of the metabolic alkalotic charge, as observed in acid–base parameters in urine, and increased the availability of Ca and P as a result of higher feed intake at the onset of lactation.