Model based development of access policies

In this paper we present a novel approach for the specification of user rights in the context of an object oriented use case driven development process. Basically, we extend the specification of methods by a permission section describing the right of some actor to call the method of an object. Our approach is both role based and context based while allowing for permissions to be specified at a fine-grained data-dependent level. We use first-order logic with a built-in notion of objects and classes (provided with an algebraic semantics) as our syntactic and semantic framework. In the second part of the paper, we demonstrate the application of this approach in a model-based context to generate permissions in distributed peer-to-peer networks.     

Asking the right questions about leadership: Discussion and conclusions.

Five questions prompted by the articles in the American Psychologist special issue on leadership (January 2007, Vol. 62, No. 1., see records 2006-23492-001, 2006-23492-002, 2006-23492-003, 2006-23492-004, 2006-23492-005, and 2006-23492-006) suggest some new directions for leadership research: (1) Not do leaders make a difference, but under what conditions does leadership matter? (2) Not what are the traits of leaders, but how do leaders' personal attributes interact with situational properties to shape outcomes? (3) Not do there exist common dimensions on which all leaders can be arrayed, but are good and poor leadership qualitatively different phenomena? (4) Not how do leaders and followers differ, but how can leadership models be reformulated so they treat all system members as both leaders and followers? (5) Not what should be taught in leadership courses, but how can leaders be helped to learn? (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis and materials characterization of Li2MnO3-LiCrO2 system nanocomposite electrode materials

A series of Li[Cr_xLi_(1−x)/3Mn_2(1−x)/3]O₂, (0.2 ≤ x ≤ 0.4) with nanocomposite structures was synthesized by a solution method with subsequent quenching. The sample structures were investigated by X-ray diffraction (Rietveld refinement), electron diffraction and HRTEM. According to co-indexed electron diffraction patterns and HRTEM images, Li[Cr_0.211Li_0.268Mn_0.520]O₂ was found to be composed of solid solution powders and Li[Cr_0.290Li_0.240Mn_0.470]O₂ and Li[Cr_0.338Li_0.225Mn_0.436]O₂ of nanocomposite powders indexed in monoclinic and hexagonal structure. Among the three compounds, the nanocomposite Li[Cr_0.290Li_0.240Mn_0.470]O₂ cathode prevented spinel-like structural transformation during cycling and delivered a good reversible capacity of about 195 mAh/g.     

Leveraging decision‐making tools in capacity building planning: The Indonesian scientific network case

Abstract

The development of investment alternatives for the Government of Indonesia's proposed scientific network forms the background to this case. The goal was to rationalize a structure for developing and sustaining a broad‐based network capable of serving scientists throughout the country, including very remote areas. It became clear that one approach could combine both technological as well as entrepreneurial elements, since the data communications linkages for serving scientists could also be available for private customers. The process of defining and costing out this approach was a textbook example of a bottom‐up analysis, beginning with customer needs and working toward structures to satisfy the needs. The World Bank and the Government of Indonesia are in the process of implementing several features of the recommended system. The proposed approach can ultimately pay for itself through private sector revenues for user services. While the context of the decision is telecommunications, the methodology is appropriate for many decision‐making situations. Samples of actual data and bottom‐line results are discussed.     

Applications of real number theorem proving in PVS

Real number theorem proving has many uses, particularly for verification of safety critical systems and systems for which design errors may be costly. We discuss a chain of developments building on real number theorem proving in PVS. This leads from the verification of aspects of an air traffic control system, through work on the integration of computer algebra and automated theorem proving to a new tool, NRV, first presented here that builds on the capabilities of Maple and PVS to provide a verified and automatic analysis of Nichols plots. This automates a standard technique used by control engineers and greatly improves assurance compared with the traditional method of visual inspection of the Nichols plots.     

Pummelos as Concept Generators for Biomimetically Inspired Low Weight Structures with Excellent Damping Properties

Natural materials often exhibit excellent mechanical properties. An example of outstanding impact resistance is the pummelo fruit (Citrus maxima) which can drop from heights of 10 m and more without showing significant outer damage. Our data suggest that this impact resistance is due to the hierarchical organization of the fruit peel, called pericarp. The project presented in the current paper aims at transferring structural features from the pummelo pericarp to engineering materials, in our case metal foams, produced by the investment casting process. The transfer necessitates a detailed structural and mechanical analysis of the biological model on the one hand, and the identification and development of adequate materials and processes on the other hand. Based on this analysis, engineering composite foam structures are developed and processed which show enhanced damping and impact properties. The modified investment casting process and the model alloy Bi57Sn43 proved to be excellent candidates to make these bio‐inspired structures. Mechanical testing of both the natural and the engineering structures has to consider the necessity to evaluate the impact of the different hierarchical features. Therefore, specimens of largely varying sizes have to be tested and size effects cannot be ignored, especially as the engineering structures might be upscaled in comparison with the natural role model. All in all, the present results are very promising: the basis for a transfer of bio‐inspired structural hierarchical levels has been set.     

Time-Resolved and Spatio-Temporal Analysis of Complex Cognitive Processes and their Role in Disorders like Developmental Dyscalculia

The aim of this article is to report on the importance and challenges of a time-resolved and spatio-temporal analysis of fMRI data from complex cognitive processes and associated disorders using a study on developmental dyscalculia (DD). Participants underwent fMRI while judging the incorrectness of multiplication results, and the data were analyzed using a sequence of methods, each of which progressively provided more a detailed picture of the spatio-temporal aspect of this disease. Healthy subjects and subjects with DD performed alike behaviorally though they exhibited parietal disparities using traditional voxel-based group analyses. Further and more detailed differences, however, surfaced with a time-resolved examination of the neural responses during the experiment. While performing inter-group comparisons, a third group of subjects with dyslexia (DL) but with no arithmetic difficulties was included to test the specificity of the analysis and strengthen the statistical base with overall fifty-eight subjects. Surprisingly, the analysis showed a functional dissimilarity during an initial reading phase for the group of dyslexic but otherwise normal subjects, with respect to controls, even though only numerical digits and no alphabetic characters were presented. Thus our results suggest that time-resolved multi-variate analysis of complex experimental paradigms has the ability to yield powerful new clinical insights about abnormal brain function. Similarly, a detailed compilation of aberrations in the functional cascade may have much greater potential to delineate the core processing problems in mental disorders.     

Making judgments about ability: The role of implicit theories of ability in moderating inferences from temporal and social comparison information.

Two studies examined the novel proposal that implicit theories of intelligence (C. S. Dweck & E. L. Leggett 1988) moderate both the effects of performance trends on ability inferences and the perceived diagnosticity of temporal versus normative feedback. Results from 613 adolescents and 42 teachers confirmed that entity theorists perceived initial outcome as more diagnostic and inferred higher ability in another (Study 1) and in the self (Study 2) in a declining outcome condition; incremental theorists perceived last outcome as more diagnostic and inferred higher ability in an ascending condition. Experimental induction of beliefs about ability had similar effects. As predicted, self-appraisal was affected more by temporal feedback among incremental theorists and by normative feedback among entity theorists. Results help resolve prior mixed findings regarding order effects and responses to temporal and normative evaluation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)