Bayesian compressive sensing framework for spectrum reconstruction in Rayleigh fading channels

Compressive sensing (CS) is a novel digital signal processing technique that has found great interest in many applications including communication theory and wireless communications. In wireless communications, CS is particularly suitable for its application in the area of spectrum sensing for cognitive radios, where the complete spectrum under observation, with many spectral holes, can be modeled as a sparse wide-band signal in the frequency domain. Considering the initial works performed to exploit the benefits of Bayesian CS in spectrum sensing, the fading characteristic of wireless communications has not been considered yet to a great extent, although it is an inherent feature for all sorts of wireless communications and it must be considered for the design of any practically viable wireless system. In this paper, we extend the Bayesian CS framework for the recovery of a sparse signal, whose nonzero coefficients follow a Rayleigh distribution. It is then demonstrated via simulations that mean square error significantly improves when appropriate prior distribution is used for the faded signal coefficients and thus, in turns, the spectrum reconstruction improves. Different parameters of the system model, e.g., sparsity level and number of measurements, are then varied to show the consistency of the results for different cases

On finite groups having a certain number of cyclic subgroups

Let $G$ be a finite group. In this paper, we study the structure of finite groups having $|G|-r$ cyclic subgroups for $3leq rleq 5$

Biomimetische Herstellung organisch- anorganischer Komposit Materialien

This work deals with mimicking structural features found in nacre to fabricate composite materials as a tough ceramic material and to explore the mechanical properties. It is part of the work package D9 ôBiomimetic Ceramicsö of the Collaborative Research Centre 599 ôSustainable bioresorbable and permanent implants of metallic and ceramic materialsö of the DFG. Structural pattern found in nacre at micro level, so called ôbrick and mortarö assembly is formed in the presence of a mixture of proteins rich in acidic amino acids with aragonite. To mimic this hierarchical pattern, an appropriate inorganic material and an adhesive polymeric partner are the prerequisite. Specific polymers are required that can be used as crystallization controlling agents in order to synthesize inorganic platelets. For this purpose different phosphonic acid functional polymers and copolymers were synthesized. Properties of the basic polymer chains were altered by copolymerization with different monomers to get desired properties. The reactivity parameters of the copolymerizing units were also established. Furthermore a mussel adhesive protein mimic was also synthesized with dopamine functionality. These polymers were tested at Leibniz University Hannover for the controlled crystallization of hydroxyapatite, with a close resemblance to natural bone material and zirconium hydrogenphosphate hydrate, a biocompatible material which layered morphology. Nanoparticles or platelets, respectively, of these inorganic materials were obtained. Layered composites of zirconium hydrogenphosphate hydrate (ZrP) platelets and chitosan were prepared by layer-by-layer assembly. The growth and structural features of the composite films were studied along with their mechanical properties with reference to the number of dipping cycles, concentration and pH. Another composite was fabricated mimicking mussel proteins as organic component. A composite was prepared by LbL assembly using alumina platelets and hydroxyethyl starch modified with dopamine. Resulting composites have shown morphological similarities as found in nacre micro structure. For composites structure-property-relationships were identified. The thickness of the composites was measured with profilometer while structural details were elucidated with SEM. The mechanical properties of the fabricated composites were investigated with nanoindentation in cooperation with Max-Planck Institute for Metals Research Stuttgart.Die vorliegende Arbeit beschäftigt sich mit der Nachbildung der strukturellen Charakteristika von Perlmutt, um auf diese Art harte Keramiken herzustellen und deren mechanische Eigenschaften zu untersuchen. Sie wurde im Rahmen des Projektes D9 „Biomimetische Keramiken“ des Sonderforschungsbereiches 599 „Zukunftsfähige bioresorbierbare und permanente Implantate aus metallischen und keramischen Werkstoffen“ der DFG durchgeführt. In der Natur entsteht die Struktur von Perlmutt, die mit einem Gefüge aus Ziegeln und Mörtel verglichen werden kann, aus Aragonit in Gegenwart eines Proteingemisches. Die Voraussetzung zur Nachahmung dieser hierarchischen Strukturen sind somit ein anorganisches Material mit entsprechender Geometrie und ein als Matrix dienendes haftfähiges Polymer. Zur Synthese der anorganischen Plättchen werden spezielle Polymere benötigt, die die Kristallisation kontrollieren. Daher wurden zunächst verschiedene Polymere mit dazu geeigneten Phosphonsäuregruppen synthetisiert. Die Eigenschaften der Polymerkette können hierbei durch die Copolymerisation mit unterschiedlichen Comonomeren verändert werden. Weiterhin wurde ein Copolymer mit der adhärierenden Dopamin-Einheit aus Muschel-Proteinen synthetisiert. Die hergestellten Polymere wurden an der Leibniz Universität Hannover zur kontrollierten Kristallisation von Hydroxylapatit, das dem natürlichen Knochen ähnelt, und Zirkonium (hydrogenphosphat)hydrat, einem biokompatiblem Material mit schichtartiger Morphologie, eingesetzt. In Abhängigkeit des eingesetzten kristallisationskontrollierenden Polymers wurden aus den anorganischen Materialien Nanopartikel oder Plättchen erhalten. Anschließend wurden aus den Zirkonium (hydrogenphosphat)hydrat-Plättchen und Chitosan schichtweise aufgebaute Komposite mit Hilfe des Layer-by-Layer Verfahrens hergestellt. Das Wachstum und die Struktur sowie die mechanischen Eigenschaften wurden in Abhängigkeit von der Anzahl der Dip-Zyklen, Konzentration und pH-Wert untersucht. Des Weiteren wurde ein Komposit mit dem nachgeahmten Muschel-Protein als organische Komponente erzeugt, indem mit Dopamin modifzierte Hydroxyethylstärke und Aluminiumoxid-Plättchen im Layer-by-Layer-Verfahren zusammengefügt wurden. Dieses zeigt morphologische Ähnlichkeiten zu der Mikrostruktur von Perlmutt. Die Schichtdicken der Komposite wurden mit einem Profilometer bestimmt und die strukturellen Details konnten an Hand von REM-Aufnahmen aufgeklärt werden. In Kooperation mit dem Max Planck Institut für Metallforschung in Stuttgart wurden die mechanischen Eigenschaften der Komposite mit Hilfe von Nanoindentation charakterisiert. Für die Komposite wurden Abhängigkeiten zwischen der Struktur und den Eigenschaften festgestellt

Statistical Modelling of the Visual Impact of Subretinal Fluid and Associated Features

Introduction: The aim of this study was to develop a statistical model to determine the visual significance of subretinal fluid (SRF) in combination with other constructed optical coherence tomography (OCT) features in patients with wet age-related macular degeneration. Methods: The project used labelled data from 1211 OCTs of patients with neovascular macular degeneration (nAMD) attending the macular treatment centre of Manchester Royal Eye Hospital to build a statistical model to determine vision for any virtual, constructed OCT. A four-dimensional plot was created to represent the visual impact of SRF in OCTs in the context of the associated OCT characteristics of atrophy and subretinal hyperreflective material (SHRM). Results: The plot illustrates that at levels of SRF below 150 µm, the impact of SRF on vision is very low. Increasing the amount of fluid to 200 µm and beyond increases the impact on vision, but only if there is little atrophy or SHRM. Conclusions: This study suggests that levels of SRF up to around 150 µm thickness on OCT have minimal impact on vision. Greater levels of SRF have greater impact on vision, unless associated with significant amounts of atrophy or SHRM, when the additional effect of the SRF on vision remains low

A Vision of DevOps Requirements Change Management Standardization

DevOps (development and operations) aims to shorten the software development process and provide continuous delivery with high software quality. To get the potential gains of DevOps, the software development industry considering global software development (GSD) environment to hire skilled human resources and round-the-clock working hours. However, due to the lack of frequent communication and coordination in GSD, the planning and managing of the requirements change process becomes a challenging task. As in DevOps, requirements are not only shaped by development feedback but also by the operations team. This means requirements affect development, development affects operations and operations affect requirements. However, DevOps in GSD still faces many challenges in terms of requirement management. The purpose of this research project is to develop a DevOps requirement change management and implementation maturity model (DevOps-RCMIMM) that could assist the GSD organizations in modifying and improving their requirement management process in the DevOps process. The development of DevOps-RCMIMM will be based on the existing DevOps and RCM literature, industrial empirical study, and understanding of factors that could impact the implementation of the DevOps requirement change management process in the domain of GSD. This vision study presents the initial results of a systematic literature review that will contribute to the development of maturity levels of the proposed DevOps-RCMIMM

Quantum Software Engineering: A New Genre of Computing

Quantum computing (QC) is no longer only a scientific interest but is rapidly becoming an industrially available technology that can potentially tackle the limitations of classical computing. Over the last few years, major technology giants have invested in developing hardware and programming frameworks to develop quantum-specific applications. QC hardware technologies are gaining momentum, however, operationalizing the QC technologies trigger the need for software-intensive methodologies, techniques, processes, tools, roles, and responsibilities for developing industrial-centric quantum software applications. This paper presents the vision of the quantum software engineering (QSE) life cycle consisting of quantum requirements engineering, quantum software design, quantum software implementation, quantum software testing, and quantum software maintenance. This paper particularly calls for joint contributions of software engineering research and industrial community to present real-world solutions to support the entire quantum software development activities. The proposed vision facilitates the researchers and practitioners to propose new processes, reference architectures, novel tools, and practices to leverage quantum computers and develop emerging and next generations of quantum software

synthesis characterization and applications of nano micro carbonaceous inerts a review

Abstract In recent years, a scientific shift has been observed towards the use of carbon based nano materials in different composites to enhance their mechanical and electrical properties. However, carbonaceous nano/micro inert particles synthesized through pyrolysis of agricultural and industrial wastes offer a very cost effective alternate to the commercially available carbon based materials such as carbon fibres, carbon nanotubes, graphene and graphene oxide. A comprehensive survey of reported data on the synthesis of carbon particles is presented in this article. The utilization of synthesized carbon particles as reinforcing material has also been explored together with an attempt of proposing future novel applications of synthesized carbon particles in cement based systems. In this paper, meticulous efforts have been made to overview the potential beneficial effects of synthesized carbon particles intrusions to cementitious systems for modifying/improving their mechanical characteristics

Quality of Life in Children with Epilepsy in Wah Cantt, Pakistan: A Cross-sectional Study

Objective: To assess the Quality Of Life (QOL) in children with epilepsy using modified QOLCE-55 questionnaire. Material and Methods: We consecutively enrolled children aged 4 to 16 years who were under treatment for childhood epilepsy. Basic demographic and clinical details including type of epilepsy, developmental history, family history of epilepsy and any co-morbidity were recorded in a predesigned Performa. QOL was evaluated by using modified QOLCE-55 (39 items) from parents. Results: A total of 54 children were enrolled in the study, 42 (78%) were males and 12(22%) were female children with epilepsy.  Eight children got good QOLCE score, while 24 children had average and 22 children got a poor score. The good score was mostly seen in 4-8 years (40%) of age while the poor score was seen in 12-16 years (70%) age group. Age of the patients (p=<0.001), gender (p=<0.001), associated co-morbidities (p=0.003) and family history of epilepsy (p=0.011) showed a significant effect on the QOLCE score. Type of epilepsy (p= 0.825) and development of a child (p=0.109) did not affect the QOLCE score significantly. Conclusion: The study showed that Children with co-morbidities, family history of epilepsy and female children of older age group (12-16 years) had poor QOL. Types of seizures and development of the child did not significantly alter the QOLCE score