Time-Constraint-Aware Optimization of Assertions in Embedded Software

Technology shrinking and sensitization have led to more and more transient faults in embedded systems. Transient faults are intermittent and non-predictable faults caused by external events, such as energetic particles striking the circuits. These faults do not cause permanent damages, but may affect the running applications. One way to ensure the correct execution of these embedded applications is to keep debugging and testing even after shipping of the systems, complemented with recovery/restart options. In this context, the executable assertions that have been widely used in the development process for design validation can be deployed again in the final product. In this way, the application will use the assertion to monitor itself under the actual execution and will not allow erroneous out-of-the-specification behavior to manifest themselves. This kind of software-level fault tolerance may represent a viable solution to the problem of developing commercial off-the-shelf embedded systems with dependability requirements. But software-level fault tolerance comes at a computational cost, which may affect time-constrained applications. Thus, the executable assertions shall be introduced at the best possible points in the application code, in order to satisfy timing constraints, and to maximize the error detection efficiency. We present an approach for optimization of executable assertion placement in time-constrained embedded applications for the detection of transient faults. In this work, assertions have different characteristics such as tightness, i.e., error coverage, and performance degradation. Taking into account these properties, we have developed an optimization methodology, which identifies candidate locations for assertions and selects a set of optimal assertions with the highest tightness at the lowest performance degradation. The set of selected assertions is guaranteed to respect the real-time deadlines of the embedded application. Experimental results have shown the effectiveness of the proposed approach, which provides the designer with a flexible infrastructure for the analysis of time-constrained embedded applications and transient-fault-oriented executable assertions.     

Comparison and assessment of coarse resolution land cover maps for Northern Eurasia

Information on land cover at global and continental scales is critical for addressing a range of ecological, socioeconomic and policy questions. Global land cover maps have evolved rapidly in the last decade, but efforts to evaluate map uncertainties have been limited, especially in remote areas like Northern Eurasia. Northern Eurasia comprises a particularly diverse region covering a wide range of climate zones and ecosystems: from arctic deserts, tundra, boreal forest, and wetlands, to semi-arid steppes and the deserts of Central Asia. In this study, we assessed four of the most recent global land cover datasets: GLC-2000, GLOBCOVER, and the MODIS Collection 4 and Collection 5 Land Cover Product using cross-comparison analyses and Landsat-based reference maps distributed throughout the region. A consistent comparison of these maps was challenging because of disparities in class definitions, thematic detail, and spatial resolution. We found that the choice of sampling unit significantly influenced accuracy estimates, which indicates that comparisons of reported global map accuracies might be misleading. To minimize classification ambiguities, we devised a generalized legend based on dominant life form types (LFT) (tree, shrub, and herbaceous vegetation, barren land and water). LFT served as a necessary common denominator in the analyzed map legends, but significantly decreased the thematic detail. We found significant differences in the spatial representation of LFT's between global maps with high spatial agreement (above 0.8) concentrated in the forest belt of Northern Eurasia and low agreement (below 0.5) concentrated in the northern taiga-tundra zone, and the southern dry lands. Total pixel-level agreement between global maps and six test sites was moderate to fair (overall agreement: 0.67-0.74, Kappa: 0.41-0.52) and increased by 0.09-0.45 when only homogenous land cover types were analyzed. Low map accuracies at our tundra test site confirmed regional disagreements and difficulties of current global maps in accurately mapping shrub and herbaceous vegetation types at the biome borders of Northern Eurasia. In comparison, tree dominated vegetation classes in the forest belt of the region were accurately mapped, but were slightly overestimated (10%-20%), in all maps. Low agreement of global maps in the northern and southern vegetation transition zones of Northern Eurasia is likely to have important implications for global change research, as those areas are vulnerable to both climate and socio-economic changes.     

On Entangled Information and Quantum Capacity

The pure quantum entanglement is generalized to the case of mixed compound states to include the classical and quantum encodings as particular cases. The true quantum entanglements are characterized as transpose-CP but not CP maps. The entangled information is introduced as the relative entropy of the mutual and the input state and total information of the entangled states leads to two different types of entropy for a given quantum state: the von Neumann entropy, which is achieved as the supremum of the information over all c-entanglements, and the true quantum entropy, which is achieved at the standard entanglement. The q-capacity, defined as the supremum over all entanglements, doubles the c-capacity in the case of the simple algebra. The conditional q-entropy is positive, and q-information of a quantum channel is additive.     

Preparation of aluminum oxide coating on carbon/carbon composites using a new detonation sprayer

A new multi-chamber cumulative detonation sprayer (MCDS) was applied to fabricate an aluminum oxide coating on carbon/carbon composites. MCDS provides heating and acceleration of ceramic micropowders by means of combustible gas mixture detonation products with a frequency of 20 Hz and above. The ceramic aluminum oxide particle kinetic energy ensures the destruction of the weakened areas on the carbon-carbon composite material surface and the incorporation of these particles into the surface layer. The following powder particles decelerate on the already fixed particles and form a ceramic coating. The formed aluminum oxide coating is characterized by high hardness and low porosity (<1%). MCDS provides the formation of a high-quality ceramic layer, which can also serve as the basis for the formation of protective heat-resistant coatings.     

Kinetic nanofriction: a mechanism transition from quasi-continuous to ballistic-like Brownian regime

ABSTRACT: Surface diffusion of mobile adsorbates is not only the key to control the rate of dynamical processes on solid surfaces, e.g. epitaxial growth, but also of fundamental importance for recent technological applications, such as nanoscale electro-mechanical, tribological, and surface probing devices. Though several possible regimes of surface diffusion have been suggested, the nanoscale surface Brownian motion, especially in the technologically important low friction regimes, remains largely unexplored. Using molecular dynamics simulations, we show for the first time, that a C60 admolecule on a graphene substrate exhibits two distinct regimes of nanoscale Brownian motion: a quasi-continuous and a ballistic-like. A crossover between these two regimes is realized by changing the temperature of the system. We reveal that the underlying physical origin for this crossover is a mechanism transition of kinetic nanofriction arising from distinctive ways of interaction between the admolecule and the graphene substrate in these two regimes due to the temperature change. Our findings provide insight into surface mass transport and kinetic friction control at the nanoscale.     

Effective sensor deployment based on field information coverage in precision agriculture

Coverage is an importance issue in wireless sensor networks. In this work, we first propose a novel notion of information coverage, which refers to the coverage efficiency of field information covered by deployed sensor nodes. On the basis of information coverage, we consider an optimization problem of how to partition the given field into multiple parcels and to deploy sensor nodes in some selected parcels such that the field information covered by the deployed sensor nodes meets the requirement. First, we develop two effective polynomial‐time algorithms to determine the deployed locations of source nodes for information 1‐coverage and q‐coverage of the field, respectively, without consideration of communication, where information q‐coverage implies that the field information in terms of information point is covered by at least q source nodes. Also, we prove the upper bound in the theoretical for the approximate solution derived by our proposed method. Second, another polynomial‐time algorithm is presented for deriving the deployed locations of relay nodes. In the theoretical, this proposed algorithm can achieve the minimized number of relay nodes. Further, the related information 1‐coverage algorithms are applied in our wireless sensor network‐based automatic irrigation project in precision agriculture. Experimental results show the major trade‐offs of impact factors in sensor deployment and significant performance improvements achieved by our proposed method. Copyright © 2013 John Wiley & Sons, Ltd.     

Text/shape classifier for mobile applications with handwriting input

The paper provides a practical solution to a real-time text/shape differentiation problem for online handwriting input. The proposed structure of the classification system comprises stroke grouping and stroke classification blocks. A new set of features is derived that has low computational complexity. The method achieves 98.5 % text/shape classification accuracy on a benchmark dataset. The proposed stroke grouping machine learning approach improves classification robustness in relation to different input styles. In contrast to the threshold-based techniques, this grouping adaptation enhances the overall discriminating accuracy of the text/shape recognition system by 11.3 %. The solution improves system’s response on a touch-screen device.     

Effect of incorporation of titanium dioxide nanocrystals on bulk properties of KDP crystals

The impact of titanium dioxide (anatase) nanocrystals on growth process, optical and structural properties of KDP single crystal was studied. As-grown crystals were characterized by High Resolution Three-crystal X-ray Diffractometer, optical diagnostics of elastic scattering, cone-shaped interference method, and spatial profile analysis method. In the composite system KDP:TiO₂ the effect of giant nonlinear optical response of anatase nanoparticles was revealed, in particular in the intensity range up to 20 MW/cm² the change of sign of the nonlinear refraction index was found. These results can be explained by the resonance excitation of defective states on TiO₂ nanoparticle surface.