Wireless Network Control with Privacy Using Hybrid ARQ

We consider the problem of resource allocation in a wireless cellular network, in which nodes have both open and private information to be transmitted to the base station over block fading uplink channels. We develop a cross-layer solution, based on hybrid ARQ transmission with incremental redundancy. We provide a scheme that combines power control, flow control, and scheduling in order to maximize a global utility function, subject to the stability of the data queues, an average power constraint, and a constraint on the privacy outage probability. Our scheme is based on the assumption that each node has an estimate of its uplink channel gain at each block, while only the distribution of the cross channel gains is available. We prove that our scheme achieves a utility, arbitrarily close to the maximum achievable utility given the available channel state information

Allocation des ressources et des solutions pour économiser de l'énergie dans les réseaux optiques d'accès

In this thesis, general overview about PON systems is presented and existing PON mechanisms and classification are investigated. After, a novel dynamic bandwidth allocation algorithm for EPON is introduced. This proposed algorithm is named as “Half Cycling Dynamic Bandwidth Allocation-hcDBA” by the inspiration of its half cycling processing mode. Later, an improvement of hcDBA algorithm with early prediction mechanism is presented. As a result statement of the study, hcDBA algorithm performs better than existing mechanism in terms of packet loss ratio and access delays. Beside, simulation traffic behavior of EPON’s upstream channel has been investigated in order to support the decision of selecting suitable traffic generator in further studies. Energy conversation is one of the hot topics in telecommunication networks. Access networks constitute remarkable portion of the total energy consumption in telecommunication networks. ITU-T and IEEE organizations published recommendation for energy conversation in PONs. While, total energy consumption of ONUs is more than other equipment in fix access network the standards and most of the researches focused on saving energy at ONU side. In this thesis I focused on an energy efficiency method based on energy conversation on OLT side. The proposed method save energy by dynamically moving OLT cards to deep sleep mode according to the incoming and outgoing traffic loadsDans ce travail de thèse, un aperçu général sur les systèmes PON est présenté et sont étudiés les mécanismes et classification PON existants. Après, nous introduisons notre première contribution qui est un algorithme d'allocation dynamique de bande passante pour EPON. Cet algorithme proposé est désigné comme «hcDBA». Par la suite, une amélioration de l'algorithme de hcDBA avec mécanisme de prédiction précoce est présentée. Notre simulation montre bien que notre algorithme hcDBA est performant comparé aux mécanismes existants en termes de taux de perte de paquets et de délai d’accès. Dans notre seconde contribution, nous sommes intéressés au problème de consommation d’énergie qui est un sujet d’actualité dans les réseaux de télécommunication. Les études montrent aujourd’hui que les réseaux d'accès constituent une partie remarquable de la consommation totale d'énergie dans les réseaux de télécommunication. Les organisations ITU-T et IEEE ont publié la recommandation pour la conversation de l'énergie pour les réseaux PONs. Bien que, la consommation totale d'énergie des nœuds ONU est plus importantes que d'autres équipements dans le réseau d'accès fixe, les normes et la plupart des travaux de recherches ont porté sur les économies d'énergie du côté de ONU. Dans cette thèse, nous sommes concentrés sur une méthode d'efficacité énergétique basée sur la conservation de l'énergie du côté de l’OLT. La méthode proposée permet d’économiser de l'énergie en déplaçant dynamiquement des cartes d’OLT en mode de sommeil profond en fonction des charges de trafic entrant et sortan

Effects of Dissolving Solutions on the Accuracy of an Electronic Apex Locator-Integrated Endodontic Handpiece

The effects of three dissolving agents on the accuracy of an electronic apex locator- (EAL-) integrated endodontic handpiece during retreatment procedures were evaluated. The true lengths (TLs) of 56 extracted incisor teeth were determined visually. Twenty teeth were filled with gutta-percha and a resin-based sealer (group A), 20 with gutta-percha and a zinc oxide/eugenol-based sealer (group B), and 16 roots were used as the control group (group C). All roots were prepared to TL. Guttasolv, Resosolv, and Endosolv E were used as the dissolving solutions. Two evaluations of the handpiece were performed: the apical accuracy during the auto reverse function (ARL) and the apex locator function (EL) alone. The ARL function of the handpiece gave acceptable results. There were significant differences between the EL mode measurements and the TL (P<0.05). In these comparisons, Tri Auto ZX EL mode measurements were significantly shorter than those of the TL

Improving Disaster Resilience Using Mobile Based Disaster Management System

AbstractThe use of ICTs can help to produce information and make better decisions for effective disaster management system. ICT is considered to necessary enhance adaptation capacity and supports feedback, ensure information access, enables active participation, reduces vulnerability. Mobile technologies are appropriate for providing these needs to improving resilience. Nowadays with the widespread use of mobile devices, benefiting as an information sharing environment after disaster is inevitable. The use of mobile technologies by citizens after a disaster increases resilience against disasters. The aim of the study is to increase disaster resilience by using mobile technologies to ensure citizens play an active role in disaster management

Comparative morphological differences between umbilical cords from chronic hypertensive and preeclamptic pregnancies.

To compare morphological changes in the umbilical cords from chronic hypertensive and preeclamptic patients having normal or pathological umbilical artery Doppler ultrasonographic results. Umbilical cords from 34 normotensive, 31 chronic hypertensive and 70 preeclamptic women with normal and abnormal Doppler flow velocity waveforms (FVW) at 35-40 gestational weeks were studied. Morphological changes in the umbilical cords were examined on formalin-fixed, paraffin-embedded sections. The total umbilical cord area, total vessel area, and wall thickness of umbilical vessels were measured in systematic random samples using unbiased stereology methods. An ANOVA test was used for statistical analysis. In the chronic hypertensive and preeclamptic groups with normal Doppler FVW, the thickness of the umbilical cord vessels remained nearly constant, whereas both the total area and the lumen area were reduced. These changes correlate with the histopathological findings, suggesting a mainly vasoconstrictive effect. By contrast, analysis of the preeclamptic group with pathologic Doppler FVW showed a comparable reduction of all parameters of the umbilical cord. Histopathological findings were related to smaller, contracted smooth muscle cells of the vessel wall, which is suggestive of a predominant hypoplastic mechanism. As a result of reduced uteroplacental perfusion, fetal hypoxia and intrauterine growth retardation become unavoidable in preeclampsia. The histopathological changes in the umbilical cord between the chronic hypertensive and preeclamptic patients depend on the Doppler results. In conclusion, the umbilical artery Doppler FVW indices provide good values for predicting intrauterine growth retardation in preeclamptic patients.</p

Energy Efficiency in Electricity Production: A Data Envelopment Analysis (DEA) Approach for the G-20 Countries

Factors such as global warming, increased energy prices, decreased security of energy supply and the vision of sustainable development have inspired researchers to focus on energy efficiency. In this context, this study adopts input oriented DEA based on the Charnes, Cooper and Rhodes (CCR) model and estimates technical and super efficiency scores of G-20 countries in terms of electricity production for the periods 1990, 1995, 2000, 2005 and 2011. Findings reveal that China and Russia appear at the top of energy efficiency rankings. On the other hand, France and the European Union are inefficient in four of five periods. Besides, the way that the United States follows for recent electricity production seems inefficient. This implies that the world has been experiencing an important transformation in terms of efficient electricity production and policy makers should be aware of this progress in order to avoid unexpected outcomes for the energy future. Keywords: Energy efficiency; Data Envelopment Analysis; G-20 countries JEL Classifications: C14; O13; O5

Modeling and fabrication of electrostatically actuated diaphragms for on-chip valving of MEMS-compatible microfluidic systems

This paper presents an analytical model to estimate the actuation potential of an electrostatic parylene-C diaphragm, processed on a glass wafer using standard microelectromechanical systems (MEMS) process technology, and integrable to polydimethylsiloxane (PDMS) based lab-on-a-chip systems to construct a normally-closed microvalve for flow manipulation. The accurate estimation of the pull-in voltage of the diaphragm is critical to preserve the feasibility of integration. Thus, we introduced an analytical model, in a good agreement with the finite element method (FEM), to extend the solution of the pull-in instability by including the effect of nonlinear stretching for multilayered circular diaphragms. We characterized the operation of fabricated diaphragms with a 300 mu m radius for the parameters, including pull-in voltage (221 V on average), opening and closing response times (in microseconds), repeatability (more than 50 times), and touch area (25.3% +/- 2.6% at pull-in potential). The experimental pull-in voltage shows close accuracy with the predicted results. Moreover, the diaphragm, sealed with a PDMS microchannel, was tested under fluid flow to prove the applicability of microfluidic integration. The hybrid fabrication method enables the realization of optically transparent and durable electrostatic microvalves for complex functioning of polymer-based microfluidic systems, as the extended analytical formulation permits accurate modeling of operation.This paper presents an analytical model to estimate the actuation potential of an electrostatic parylene-C diaphragm, processed on a glass wafer using standard microelectromechanical systems (MEMS) process technology, and integrable to polydimethylsiloxane (PDMS) based lab-on-a-chip systems to construct a normally-closed microvalve for flow manipulation. The accurate estimation of the pull-in voltage of the diaphragm is critical to preserve the feasibility of integration. Thus, we introduced an analytical model, in a good agreement with the finite element method (FEM), to extend the solution of the pull-in instability by including the effect of nonlinear stretching for multilayered circular diaphragms. We characterized the operation of fabricated diaphragms with a 300 µm radius for the parameters, including pull-in voltage (221 V on average), opening and closing response times (in microseconds), repeatability (more than 50 times), and touch area (25.3% ± 2.6% at pull-in potential). The experimental pull-in voltage shows close accuracy with the predicted results. Moreover, the diaphragm, sealed with a PDMS microchannel, was tested under fluid flow to prove the applicability of microfluidic integration. The hybrid fabrication method enables the realization of optically transparent and durable electrostatic microvalves for complex functioning of polymer-based microfluidic systems, as the extended analytical formulation permits accurate modeling of operation

The Design and Implementation of Elastic Quotas: A System for Flexible File System Management

We introduce elastic quotas, a disk space management technique that makes disk space an elastic resource like CPU and memory. Elastic quotas allow all users to use unlimited amounts of available disk space while still providing system administrators the ability to control how the disk space is allocated among users. Elastic quotas maintain existing persistent file semantics while supporting user-controlled policies for removing files when the file system becomes too full. We have implemented an elastic quota system in Solaris and measured its performance. The system is simple to implement, requires no kernel modifications, and is compatible with existing disk space management methods. Our results show that elastic quotas are an effective, low-overhead solution for flexible file system management