Perfect tag identification protocol in RFID networks

Radio Frequency IDentification (RFID) systems are becoming more and more popular in the field of ubiquitous computing, in particular for objects identification. An RFID system is composed by one or more readers and a number of tags. One of the main issues in an RFID network is the fast and reliable identification of all tags in the reader range. The reader issues some queries, and tags properly answer. Then, the reader must identify the tags from such answers. This is crucial for most applications. Since the transmission medium is shared, the typical problem to be faced is a MAC-like one, i.e. to avoid or limit the number of tags transmission collisions. We propose a protocol which, under some assumptions about transmission techniques, always achieves a 100% perfomance. It is based on a proper recursive splitting of the concurrent tags sets, until all tags have been identified. The other approaches present in literature have performances of about 42% in the average at most. The counterpart is a more sophisticated hardware to be deployed in the manufacture of low cost tags.Comment: 12 pages, 1 figur

An automated model-based test oracle for access control systems

In the context of XACML-based access control systems, an intensive testing activity is among the most adopted means to assure that sensible information or resources are correctly accessed. Unfortunately, it requires a huge effort for manual inspection of results: thus automated verdict derivation is a key aspect for improving the cost-effectiveness of testing. To this purpose, we introduce XACMET, a novel approach for automated model-based oracle definition. XACMET defines a typed graph, called the XAC-Graph, that models the XACML policy evaluation. The expected verdict of a specific request execution can thus be automatically derived by executing the corresponding path in such graph. Our validation of the XACMET prototype implementation confirms the effectiveness of the proposed approach.Comment: 7 page

Transcending Towards Personal Freedom: Exploring the Lived Experiences of Professional Working Mothers

“What are the lived experiences of professional working mothers?” An integrated theoretical model provided an historical context and framework for discovering distinctions between social discourse and individual lifestyles. Professional working mothers participated in phenomenological research with an introductory telephone call and two in-person interviews. Through language and story, participants depicted what it means to be a professional working mother in contemporary, American society. Demographic characteristics included five female participants, who held a professional or executive level position. All participants earned a college degree and ranged in age from 30-65 with children living at home (ages ranged from 3-20). Additionally, four of the participants were married. Thematically, participants described their world in terms of employer and employee job expectations, an intertwining commitment to work and family, and living in alignment with one’s personal values when it comes to work-life balance. Mirroring the findings of similar studies, social conditioning, work culture, and technology heavily influenced their lived experiences as professional working mothers. Often prolonged work-life imbalances led to personal crises and fatigue; inspired to transcend old work-life paradigms, most women consciously created an integrated lifestyle, blending work and family to complement one another. Aligned with a global trend towards the integration of spiritual, social, and scientific/technological evolution, more research is required to (a) discern how self-identity and society co-create the lived experiences of professional working mothers; (b) research organizational development structures to support integrated lifestyles and, (c) evaluate the impact of ongoing work-life balance issues for future generations

Un Miroir De Mariage: an Iconological Analysis of the Bal Des Sauvages and Combat Des Hommes Sauvages et Chevaliers Tapestries

The enigmatic fifteenth-century tapestry fragments Bal des Sauvages and Combat des Hommes Sauvages et Chevaliers from the Château Saumur depict curious scenes of Wildfolk and humans. These fragments have received relatively little scholarly analysis. My thesis seeks to discern the subject matter and historical context of the des Sauvages tapestries in order to ascertain a clearer understanding the pieces. I accomplish this first by considering the des Sauvages tapestries’ historiography and examining the veracity of the various scholarly hypotheses put forth regarding the works and their subject matter. Chapter II of this thesis considers the tapestry medium and provides brief but necessary foundational information for my subsequent analysis of the des Sauvages tapestries’ context of creation and display. The third and fourth chapters consider the Wildman motif and its history in art, literature, and society, before and during the fifteenth century. The final chapter is an in-depth analysis of the Bal des Sauvages and Combat des Hommes Sauvages et Chevaliers tapestries, from which various conclusions are drawn. Among the more significant conclusions is that, while a specific narrative referent for the des Sauvages tapestry remains unknown, the Bal des Sauvages certainly depicts a scene of nuptial celebration. I argue that the tapestries’ deeper theme is likely an allegory for fifteenth-century aristocratic marriage and its accompanying morals and anxieties. This research, finally, allows me to make informed speculation about the original circumstances of the des Sauvages tapestries, their creation, ownership, original intent, and interpretation

Micro-evaporators for kinetic exploration of phase diagrams

We use pervaporation-based microfluidic devices to concentrate species in aqueous solutions with spatial and temporal control of the process. Using experiments and modelling, we quantitatively describe the advection-diffusion behavior of the concentration field of various solutions (electrolytes, colloids, etc) and demonstrate the potential of these devices as universal tools for the kinetic exploration of the phases and textures that form upon concentration

structural integrity of tied arch bridges affected by instability phenomena

Abstract A numerical study is developed to investigate out-of-plane buckling instability of tied arch bridges due to vertical loads. In particular, a numerical model is implemented to evaluate initial configuration under dead loads and nonlinearities due to nonlinear geometric effects in bridge components arising from instability phenomena. The main aim of the paper is to identify the most relevant bridge components, which are affected out-of-plane instability behavior of the structure. The nonlinear behavior of tied arch bridges is evaluated by means of a three-dimensional finite element model, in which several wind bracing system layouts and cable system configurations are considered. A comparative analysis between Elastic Buckling Analysis and Nonlinear Elastic Analysis methodologies is developed to achieve a more accurate evaluation of the maximum capacity of the structure against instability phenomena. Comparisons in terms of buckling assessment between numerical evaluations and simplified methodologies reported in current codes on bridge structures are proposed. Results show that the simplified methodologies overestimate the instability capacity in most of the bridge configurations, which have been dimensioned according to the preliminary design rules commonly adopted in current applications

Successes and Challenges for Diagnosis and Therapy of Acute Leukemia

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A cohesive finite element model based ALE formulation for z-pins reinforced multilayered composite beams

AbstractA computational formulation able to simulate fast crack growth in multilayered composite reinforced with z-pins is proposed. In particular, in order to identify the initiation and the growth of the crack, a moving mesh strategy, based on ALE approach, is combined with a cohesive methodology, in which weak based moving connections with the boundary adjoining layers are implemented by using a finite element formulation. Contrarily, z-pin reinforced area was simulated with a deformation of a set of discrete nonlinear springs fixed to material domain. Despite existing methodologies available from the literature, the present paper proposes a computational procedure able to study the dynamic crack growth in composite structures with a relatively low computational efforts. The analysis is proposed also in a non-stationary framework, in which the influence of time dependence and the inertial forces is taken into account. In order to investigate the accuracy and to validate the proposed methodology, comparisons with experimental data and numerical results are compared. Finally, the parametric study in terms of z-pins characteristics is also developed

A coupled ALE-Cohesive formulation for interfacial debonding propagation in sandwich structures

Abstract A numerical model to predict debonding phenomena in sandwich structures based on soft core and high performance external skins is proposed. In particular, the proposed model incorporates shear deformable beams to simulate the face sheet and a 2D elastic domain to model the core of the structure. Debonding processes is simulated by means a moving interface elements, introduced between the core and the face. The numerical interface strategy is consistent to a moving mesh technique based on Arbitrary Lagrangian–Eulerian (ALE), in which weak based moving connections are implemented by using the FE formulation. The moving mesh technique combined with a multilayer formulation ensures a reduction of the computational costs required to predict crack onset and subsequent evolution of the debonding phenomena. The accuracy of the proposed approach is verified by means comparisons with experimental and numerical results. Moreover, simulations in dynamic framework are developed to identify the influence of inertial effects produced by different typologies of core on debonding phenomena. The investigation revels the impact of mechanical properties of core on the dynamic debonding mechanisms