404 research outputs found
Specific heat of aluminium-doped superconducting silicon carbide
The discoveries of superconductivity in heavily boron-doped diamond, silicon
and silicon carbide renewed the interest in the ground states of charge-carrier
doped wide-gap semiconductors. Recently, aluminium doping in silicon carbide
successfully yielded a metallic phase from which at high aluminium
concentrations superconductivity emerges. Here, we present a specific-heat
study on superconducting aluminium-doped silicon carbide. We observe a clear
jump anomaly at the superconducting transition temperature 1.5 K indicating
that aluminium-doped silicon carbide is a bulk superconductor. An analysis of
the jump anomaly suggests BCS-like phonon-mediated superconductivity in this
system.Comment: 4 pages, 2 figure
RedAlert: Determinacy Inference for Prolog
This paper revisits the problem of determinacy inference addressing the
problem of how to uniformly handle cut. To this end a new semantics is
introduced for cut, which is abstracted to systematically derive a backward
analysis that derives conditions sufficient for a goal to succeed at most once.
The method is conceptionally simpler and easier to implement than existing
techniques, whilst improving the latter's handling of cut. Formal arguments
substantiate correctness and experimental work, and a tool called 'RedAlert'
demonstrates the method's generality and applicability.Comment: Theory and Practice of Logic Programming, 2011, 27th Int'l.
Conference on Logic Programming (ICLP'11) Special Issue, volume 11, issue 4-
Evidence for Multiple Phase Transitions in La_1-xCa_xCoO_3
We report thermal-expansion and specific-heat data of the series
La_1-xCa_xCoO_3 for 0 <= x <= 0.3. For x = 0 the thermal-expansion coefficient
alpha(T) features a pronounced maximum around T = 50 K caused by a
temperature-dependent spin-state transition from a low-spin state (S=0) at low
temperatures towards a higher spin state of the Co^3+ ions. The partial
substitution of the La^3+ ions by divalent Ca^2+ ions causes drastic changes in
the macroscopic properties of LaCoO_3. Around x ~ 0.125 the large maximum in
alpha(T) has completely vanished. With further increasing x three different
anomalies develop
Using all potential -sustaining workability and productivity through age specifĂc working
Much has been said and written about the facts and implications ofdemographic
change over the recent years. The message seems to slowly land: Oursociety is ageing,
and so is Europe’s workforce. Thanks to various European and national initiatives
and programmes, “age management in the workplace” has become a much-used term
amongst researchers and practitioners in the fields ofoccupational Sciences, workplace
health-promotion and related areas. Nevertheless- due to prevailing early-retirement practices in many countries over the last decades - the concept of“age specifĂc working”
or even the notion ofhaving to deal with an older workforce in the nearer future is still
pretty new to those who will be most affected by the current developments: Europe’s
companies and organisations, especially the many smaller ones among the
Like on Different Planets? Lebanese Social Scientists in Their Scientific Communities
Social sciences and humanities (SSH) at Arab universities are often described as suffering from a lack of academic freedom. However, institutional autonomy and the individual academic's opportunities and constraints seem to differ considerably among Arab institutions. Individuals conducting social sciences and humanities under different configurations of local, regional and international influences from the state, the market and the civil society. One problem made evident by existing research literature about Arab social sciences is the comparably weak networking capacity of its academic publishing and library systems. It suggests over-dependence upon international systems, a lack of direct communication amongst local and regional scientific communities, and intellectual bigotry. This article sheds light on the question how Arab institutions and individuals cope with this particular shortcoming in their academic system. It focuses on correlations between institutional and individual autonomy as measured by the modes of decision making and funding. The article will also explore the relationship between an institution's autonomy and its interconnectedness as measured by its library services and by references in faculty's dissertations. Data stem from interviews with faculty, surveys among students, and visits to libraries of two different universities in Lebanon, which are analyzed in comparison. Moreover, several networking initiatives are characterized by which social scientists in the region tackle this problem. Through private initiative, these academics seem to recover regional coherence based on Arab language and experience
Correct Reasoning about Logic Programs
In this PhD project, we present an approach to the problem of determinacy inference in logic programs with cut, which treats cut uniformly and contextually. The overall aim is to develop a theoretical analysis, abstract it to a suitable domain and prove both the concrete analysis and the abstraction correct in a formal theorem prover (Coq). A crucial advantage of this approach, besides the guarantee of correctness, is the possibility of automatically extracting an implementation of the analysis
When Crisis Promotes Proximity
During the Lebanese war of 1975 to 1990, the only public university of Lebanon branched out into more than 40 locations all over the country. While this deed reflects the inner division of Lebanon, it also moved the University nearer to the country’s geographical and social peripheries. Employing field research, newspaper articles, and grey literature this article gauges the effects of fragmentation in terms of the dynamics of social control that resulted from it. It shows that by the perspective of social control, sectarianism and clientelism can be observed as related with, but distinct from one another
A Comparison and Evaluation of Three Different Pose Estimation Algorithms In Detecting Low Texture Manufactured Objects
This thesis examines the problem of pose estimation, which is the problem of determining the pose of an object in some coordinate system. Pose refers to the object\u27s position and orientation in the coordinate system. In particular, this thesis examines pose estimation techniques using either monocular or binocular vision systems. Generally, when trying to find the pose of an object the objective is to generate a set of matching features, which may be points or lines, between a model of the object and the current image of the object. These matches can then be used to determine the pose of the object which was imaged. The algorithms presented in this thesis all generate possible matches and then use these matches to generate poses. The two monocular pose estimation techniques examined are two versions of SoftPOSIT: the traditional approach using point features, and a more recent approach using line features. The algorithms function in very much the same way with the only difference being the features used by the algorithms. Both algorithms are started with a random initial guess of the object\u27s pose. Using this pose a set of possible point matches is generated, and then using these matches the pose is refined so that the distances between matched points are reduced. Once the pose is refined, a new set of matches is generated. The process is then repeated until convergence, i.e., minimal or no change in the pose. The matched features depend on the initial pose, thus the algorithm\u27s output is dependent upon the initially guessed pose. By starting the algorithm with a variety of different poses, the goal of the algorithm is to determine the correct correspondences and then generate the correct pose. The binocular pose estimation technique presented attempts to match 3-D point data from a model of an object, to 3-D point data generated from the current view of the object. In both cases the point data is generated using a stereo camera. This algorithm attempts to match 3-D point triplets in the model to 3-D point triplets from the current view, and then use these matched triplets to obtain the pose parameters that describe the object\u27s location and orientation in space. The results of attempting to determine the pose of three different low texture manufactured objects across a sample set of 95 images are presented using each algorithm. The results of the two monocular methods are directly compared and examined. The results of the binocular method are examined as well, and then all three algorithms are compared. Out of the three methods, the best performing algorithm, by a significant margin, was found to be the binocular method. The types of objects searched for all had low feature counts, low surface texture variation, and multiple degrees of symmetry. The results indicate that it is generally hard to robustly determine the pose of these types of objects. Finally, suggestions are made for improvements that could be made to the algorithms which may lead to better pose results
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