Récemment, beaucoup de schémas parallèles en temps ont et e propos es pour résoudre des problèmes a valeur initiale de la forme (S): dY dt = F(Y ); Y (t0) = Y0, pouvant résulter, par exemple, de la semi-discretisation en espace d'équations aux derivees partielles. L'intégration des problèmes d'évolution étant naturellement séquentielle, de tels schémas ont pour principale motivation de résoudre des problèmes en temps réel ou de se superposer a un parallélisme a travers l'espace ou la méthode et ce, pour un usage plus efficace des machines fortement parallèles disponibles actuellement. Dans cette thèse, nous proposons l'algorithme RaPTI, qui permet de paralléliser en temps la résolution du problème (S), lorsque le comportement de la solution est connu. Une méthode de calcul par tranches est a la base de ce nouveau schéma. Elle consiste en (i) une procédure de génération de tranches de temps basée sur une condition de n de tranche que la solution doit vérifer et (ii) un redimensionnement de la variable temps et de la solution qui les initialise a zéro au début de chaque tranche de temps. Ainsi, la résolution de (S) devient équivalente a la résolution d'une suite de problèmes redimensionnes a valeur initiale et avec condition de fi n de tranche, donnant a la fois la solution sur chacune des tranches et le temps de fin de tranche. L'algorithme RaPTI utilise donc cette méthodologie, et certaines propriétés de similarité qui en découlent, pour générer la grille de temps grossière et fournir des prédictions au moyen d'une méthode de ratios. La procédure de correction se fait ensuite, sur une grille de temps fine, en résolvant en parallèle les systèmes redimensionnes. Ceci conduit a des sauts sur la grille de temps grossière. Les prédictions sont alors corrigées et le processus est itéré jusqu'à ce que tous les sauts soient inférieurs a une certaine tolérance. L'originalité de l'algorithme RaPTI réside dans le fait que les prédictions, et leur corrections a chaque itération, ne nécessitent aucune résolution sur la grille de temps grossière, contrairement aux autres schémas parallèles en temps. De plus, il ne commence pas par un choix de la grille grossière, mais plutôt par le choix d'une condition de fin de tranche qui va générer cette grille de façon bien adaptée au comportement de la solution. L'algorithme RaPTI est applique, dans cette thèse a trois problèmes: un problème de membrane, un problème de reaction-diffusion et un calcul de trajectoire de satellite dans un mouvement perturbe en J2. Dans quelques rares cas d'invariance, il conduit a un parallélisme parfait. Dans les cas plus courants de similarité asymptotique ou faible, il donne de bons speed-ups.

Cette thèse s'articule en deux parties. Dans la première, nous étudions les équations de Saint- Venant qui modélisent le comportement des océans, et de façon générale des fluides homogènes peu profonds, au voisinage de l'équateur dans le cadre d'une rotation rapide de la Terre. Grâce à ces hypothèses et aux équations de Navier-Stokes, nous commencerons par obtenir un modèle également connu sous le nom d' Equatorial Shallow Water System . Les équations obtenues font apparaître un paramètre de pénalisation " contenant les hypothèses de petitesse faites pour obtenir ce système simplifié. L'étude de la matrice de pénalisation permettra par une méthode de filtrage d'exhiber un système limite formel lorsque le paramètre " tend vers zéro pour lequel nous donnerons une condition nécessaire et su sante de globalité. Nous montrerons ensuite la convergence des solutions filtrées vers la solution du système limite. Dans la deuxième partie, nous exhiberons une classe de données initiales engendrant une solution globale aux équations de Navier-Stokes dans R3. En e et, les solutions de ces équations sont globales dans le cadre bidimensionnel mais dans le cas tridimensionnel, il faut rajouter, par exemple, des conditions su santes de petitesse des données initiales pour que la solution n'explose pas en temps ni. Nous prouverons que si on considère une donnée initiale ayant un spectre proche du plan horizontal alors elle engendre une solution globale des équations de Navier-Stokes. De plus, nous montrerons que, sous certaines hypothèses, la perturbation d'une donnée initiale engendrant une solution globale, par ce type de données au spectre quasi-horizontal, engendre encore une solution globale.

近年來由於網際網路的興起，加上寬頻網路的日漸普及，使得很多人會進入這以網際網路架構為核心的市場，像我們所熟悉的Skype和Smartphone都是因為網際網路興起所誕生的產物，兩者也都在市場上有爆發性的發展與成長，另外手機開始漸漸整合各種的資訊產品，不論是相機、MP3、錄音筆、電動玩具、甚至於電腦都開始慢慢的被取代，隨著新的通訊技術迅速的誕生，消費者勢必選擇傳輸數度更快、更省電的產品，因此雙網手機會是未來手機發展的趨勢，而本論文也就是基於此項原因，進而對雙網手機未來可能發展的方向做相關的研究。 本論文內容主要是瞭解整個無線通訊產業的生態，包括手機製造產業五力分析，手機未來設計可能的發展方向，行動通訊營運商、手機製造商、行動內容業者三者之間微妙的互動關係與如何共同開拓行動通訊產業市場，進而提出對於價值創新理論的理論性意涵與建立雙網手機市場的實務性意涵，以期對於我國手機製造業有所貢獻，讓國內手機製造業可以立足於全球之頂端。

Στις σύγχρονες τηλεπικοινωνίες, χρησιμοποιείται μια μεγάλη γκάμα από RF μοντέλα, για τον υπολογισμό την μέσης τιμής ισχύος του σήματος εκπομπής για δεδομένη απόσταση από τον πομπό και για δεδομένη συχνότητα. Στις διεργασίες αυτές , επιδρούν στο δικό τους βαθμό διάφορες παράμετροι τοπολογικού (πληθυσμός , τύπος εμποδίων, πυκνότητα εμποδίων) και γεωγραφικού (μορφολογία εδάφους, υγρασία, διαμόρφωση χώρου) χαρακτήρα, αλλά και χαρακτηριστικά των πομποδεκτών ( συνήθως το ύψος και το κέρδος των κεραιών). Στις περισσότερες περιπτώσεις οι απώλειες όδευσης (Path Loss όπως είναι γνωστές στη διεθνή βιβλιογραφία) , εκφράζονται σε dB , σα συνάρτηση της συχνότητας λειτουργίας του υπό μελέτη συστήματος και της απόστασης ανάμεσα στον πομπό και το δέκτη ( πάντα για δεδομένα χαρακτηριστικά κεραιών και τύπο περιβάλλοντος). Έτσι μια ντετερμινιστική γνώση του μέσου path loss, που σε συνδυασμό με άλλες πιθανές απώλειες μας δίνει το σύνολο των απωλειών είναι εφικτή. O περιορισμός όσον αφορά στη συχνότητα και στις αποστάσεις , έχουν οδηγήσει τη σύγχρονη έρευνα στην επέκταση των υπαρχόντων μοντέλων , τόσο εξωτερικού όσο και εσωτερικού χώρου. Μια βασική παράμετρος της έρευνας στηρίζεται στην παραδοχή πως ο νόμος του αντιστρόφου τετραγώνου , ο οποίος περιγράφεται από την εξίσωση του Friis δε βρίσκει εφαρμογή, παρά μόνο σε περιβάλλοντα όπου επιτυγχάνεται LOS( Line of Sight) όδευση. Η τροποποίηση της παραπάνω εξίσωσης με δυναμικό ως προς το εκάστοτε περιβάλλον τρόπο , επιτρέπει πλέον τον υπολογισμό της μέσης ισχύος του σήματος σε σχετικά ρεαλιστικό βαθμό. Για παράδειγμα έχει προταθεί τροποποίηση με την τρίτη δύναμη της απόστασης για ένα σύνολο εφαρμογών , που αφορούν συστήματα ασυρμάτων τηλεπικοινωνιών εξωτερικού περιβάλλοντος.Ένα εσωτερικό περιβάλλον απαιτεί μια πολύ πιο ντετερμινιστική φόρμουλα υπολογισμού των απωλειών ώστε να μπορέσει ο μελετητής να υπολογίσει με αξιοπιστία την ισχύ του σήματος σε μια δεδομένη θέση. Η ακρίβεια λοιπόν των μοντέλων εξαρτάται άμεσα από την ικανότητά τους να απεικονίσουν και να αποδώσουν με τη σειρά τους , μέσω των υπολογισμών, όλα αυτά τα σύνθετα φαινόμενα με τον καλύτερο δυνατό τρόπο. Η πλειοψηφία των RF μοντέλων που αναπτύσσονται στα πλαίσια ακόλουθων παραγράφων, έχει αναπτυχθεί και αξιολογηθεί για συστήματα κυτταρικής κινητής τηλεφωνίας (GSM, PCS-1800, GPRS, UMTS). Προκειμένου να ξεπεραστούν διάφοροι περιορισμοί των αρχικών μοντέλων ως προς την συχνότητα λειτουργίας του συστήματος και την απόσταση πομπού-δέκτη (ουσιαστικά την εμβέλεια του μοντέλου), ορισμένες προεκτάσεις έχουν παρουσιαστεί σε διάφορες ερευνητικές εργασίες και χρησιμοποιούνται ευρέως . Ορισμένα νέα μοντέλα έχουν επίσης προστεθεί στα ήδη υπάρχοντα για τις συχνότητες συστημάτων κινητής τηλεφωνίας . Για άλλες περιοχές συχνοτήτων με έντονο ενδιαφέρον, πχ στα 5,2 GHz, διάφορες προτάσεις έχουν πραγματοποιηθεί, συχνά υποστηριζόμενες από μετρήσεις. Λαμβάνοντας υπόψη την συχνότητα των 2,4 GHz, δεν μπορούμε παρά να συμπεράνουμε ότι η όσο το δυνατόν πιο ακριβής και επιστημονικά αξιόπιστη μοντελοποίηση του ασύρματου διαύλου, ιδιαίτερα – άλλα όχι αποκλειστικά – για τοπολογίες εσωτερικών χώρων, είναι πολύ σημαντική για τον σχεδιασμό και την εύρυθμη λειτουργία των Wi-Fi συστημάτων και των WLAN δικτύων. Παρόλα αυτά, αν και στην υπάρχουσα βιβλιογραφία και στην διεθνή επιστημονική και ερευνητική κοινότητα υπάρχουν αρκετά σημαντικές εργασίες για την μοντελοποίηση του ασύρματου διαύλου στα 2,4 GHz , εντούτοις απουσίαζε, για πολύ καιρό, μία ολοκληρωμένη συγκριτική αντιπαραβολή και αξιολόγηση των βασικών θεωρητικών μοντέλων για τον υπολογισμό της μέσης απώλειας οδεύσεως στη συγκεκριμένη συχνότητα. Στα πλαίσια της εργασίας αυτής , θα προσπαθήσουμε να αξιοποιήσουμε το σύνολο των μετρήσεων και των δεδομένων που συλλέξαμε , σε ρεαλιστικές συνθήκες και για πραγματικά συστήματα μετάδοσης , τόσο να αξιολογήσουμε τα ήδη υπάρχοντα RF μοντέλα , όσο και να προβούμε στις απαραίτητες προτάσεις και τροποποιήσεις όπου αυτό κριθεί σκόπιμο. Επίσης για τη σκίαση επιχειρούμε εδώ μια προσέγγιση υπολογισμού μέσω της χρήσης των RF μοντέλων και την ενσωμάτωση όλων των χαρακτηριστικών διάδοσης , που αφορούν και στα δύο στοιχεία των μεγάλης κλίμακας διαλείψεων. Οι μετρήσεις μέσης λαμβανόμενης ισχύος πραγματοποιήθηκαν σε πέντε διαφορετικές τοπολογίες. Σε κάθε μία από αυτές τις τοπολογίες ελήφθησαν μετρήσεις της μέσης λαμβανόμενης ισχύος σε διάφορες δειγματοληπτικές αποστάσεις πομπού-δέκτη ούτως ώστε να είναι εφικτή, με έναν υψηλό βαθμό αξιοπιστίας, η αξιολόγηση των βασικών μοντέλων απωλειών οδεύσεως. Ταυτόχρονα, μέσα από αυτή την διαδικασία, αξιολογήθηκε η αξιοπιστία των μοντέλων αναφορικά με τις ιδιαιτερότητες της κάθε τοπολογίας, που αποτυπώνονται ποιοτικά και ποσοτικά στους μηχανισμούς διάδοσης του ραδιοσήματος σε κάθε περίπτωση. / In modern wireless communications, a wide range of RF models are used to provide the median (average) value of the signal strength at a given distance from the transmitter and for a given frequency spectrum. In this procedure, certain geographical (ground, humidity, terrain irregularities), topological (heavy or scattered population, type of obstacles, density of the buildings) characteristics of the area, as well as certain specifications of the transmitter and receiver antennas (most notably antenna height and antenna gain) have to be taken into consideration. In most cases, the mean value of the path loss is expressed in dB in dependence with the frequency of the operating system and the distance between the transmitter and the receiver (for given antenna characteristics and a certain type of environment where the system operates). Thus, a deterministic knowledge of the average path loss (which along with the average rain loss and diffraction loss provides the overall propagation loss in dB) is available. However, distance and frequency limitations have led research to a further study and expanding of the existing empirical and semi-empirical models , for both outdoor and indoor scenarios. A fundamental parameter-based study of the path loss models is based on the concept that the second power law that is predicted by the Friis equation does not apply in real-life scenarios except for standard LOS paths. The modified power law research allows engineers and scholars to calculate the mean received power of a signal transmitted over a wireless link in a more realistic approach. It has been suggested that the third-power law is more suitable for a plethora of applications based on wireless communications for an outdoor environment.The indoor propagation channel, in particular, demands a lot more than a deterministic formula of calculating the average signal strength as a function of distance and frequency. The increased impact of multipath and other propagation phenomena such as reflection and scattering, as well as the existence of many objects whose proportions are comparatively close to the wavelength of the operating wireless systems, render the propagation of a signal and its arrival at a receiver (mobile or fixed) a rather complex procedure. The precision of the path loss models depends heavily on their ability to demonstrate and reflect, in the calculations, these complex phenomena to the best possible way .The majority of these models have been developed and validated for mobile telephony systems in both outdoor and indoor schemes (GSM, PCS-1800, GPRS, UMTS). Certain extensions of many of these models were conducted in order to expand the frequency and distance limitation of the original formulas. New empirical models have also been suggested for these certain frequencies .Taking into account the very sensitive and subject to many different factors nature of the indoor propagation channel, it is easily concluded that both researchers in academia and engineers in industry need to have reliable models that will predict precisely the average path loss over the indoor 2.4 GHz channel which is of utter importance as the de facto frequency of Wi-Fi and WLAN systems. A gap in aforementioned research, however, is that it either concentrates on multipath parameters or does not feature a full comparative validation of most well-known indoor path loss models.The purpose of this work is to present, all the data collected through experiments in realistic conditions and real telecom systems, in order to validate and modify (where necessary) the existing RF models. Furthermore an empirical formula to measure attenuation due to shadowing is derived through these RF models.Measurements took part in five different topologies. In each of them the mean received power was recorded, for various distances between the transmitter and the receiver, in order for our endeavor to validate the RF models in question to be reliable. Through this procedure, RF models where examined towards each topology’s distinctive characteristics that reflect in quality and quantity all the attenuation mechanisms that affect the propagated signal.

Ο όρος ‘Δίκτυα Επόμενης Γενιάς’ αναφέρεται σε μελλοντικά δίκτυα πρωτοποριακής λογικής και δομής, προσανατολισμένα στην υποστήριξη σύγχρονων απαιτητικών εφαρμογών και στη βελτίωση της λειτουργικότητας της τερματικής συσκευής, όπως την αντιλαμβάνεται ο χρήστης. Πολύ σημαντικά στοιχεία της νέας τηλεπικοινωνιακής πραγματικότητας που επιφέρουν τα δίκτυα αυτά, και με τα οποία σχετίζεται άμεσα η παρούσα εργασία, είναι η διάθεση προώθησης της γενικευμένης κινητικότητας των ασύρματων χρηστών και η ενθάρρυνση της σύγκλισης επιμέρους τεχνολογιών διαφορετικών δικτύων και της δημιουργίας υβριδικών ετερογενών δικτύων, με στόχο την επίτευξη καλύτερης αξιοποίησης του φάσματος και βελτίωσης των ρυθμών μετάδοσης δεδομένων. Σκοπός της παρούσας διπλωματικής εργασίας είναι η παρουσίαση της δομής και των λειτουργιών των Δικτύων Επόμενης Γενιάς, καθώς και ορισμένων υπαρχόντων τύπων ασύρματων δικτύων, η συνεργασία των οποίων θα μπορούσε να προσφέρει τα επιθυμητά πλεονεκτήματα. Δύο τέτοια είδη δικτύων είναι το δίκτυο κινητής τηλεφωνίας UMTS και τα τοπικά δίκτυα τεχνολογίας WLAN, τα οποία εξετάζονται ενδελεχώς ως προς τα χαρακτηριστικά τους και, κυρίως, ως προς τους μηχανισμούς διευθέτησης της περιαγωγής των χρηστών. Περιλαμβάνεται επίσης μία περιγραφή της λειτουργίας του Mobile IP, πρωτοκόλλου που θεωρείται ιδιαίτερα χρήσιμο για τη διαχείριση της κινητικότητας χρηστών ανάμεσα σε περιοχές εξυπηρέτησης διαφορετικών δικτύων. Η εργασία καταλήγει στη μοντελοποίηση των παραπάνω συστημάτων σε περιβάλλον εξομοίωσης, επιδιώκοντας την αξιολόγηση της αποτελεσματικότητας του ενδεχόμενου συνδυασμού των συστημάτων UMTS και WLAN και της χρησιμότητας του Mobile IP. Το λογισμικό που χρησιμοποιείται γι’ αυτόν το σκοπό είναι το OPNET Modeler ®, ένα πρόγραμμα που αναδεικνύεται τα τελευταία χρόνια σε εργαλείο όλο και περισσότερο πολύτιμο, τόσο σε ερευνητικό όσο και σε επιχειρησιακό επίπεδο. / The term ‘Next Generation Networks’ refers to future networks of revolutionary concept and structure, oriented to the support of demanding applications and the upgrade of the terminal device’s functionality, as perceived by the user. Some very important aspects of the new telecommunications reality that is brought on by these networks, and to which this project is directly related, is the intention of promoting generalized mobility for the wireless users and the encouragement of the convergence of distinct network technologies and of the foundation of new hybrid heterogeneous networks, in order to achieve better spectrum utilization and improvement of data transmission rates. The purpose of the current diploma thesis project is to present the structure and the functions of the Next Generation Networks, as well as of some existing types of wireless networks, the cooperation of which could provide the desirable advantages. Two such network types are the UMTS mobile telephony network and the local networks of WLAN technology, that are examined thoroughly towards their characteristics and, foremost, towards their roaming arrangement mechanisms. Also included is a description of the operation of Mobile IP, a protocol that is considered particularly convenient for the management of users’ mobility between service areas of different networks. The project concludes to the modeling of the above mentioned systems in a simulation environment, aiming to evaluate the efficiency of the prospective combination of the UMTS and WLAN systems and the utility of Mobile IP. The software used for this purpose is OPNET Modeler ®, a program that has emerged during the last years as an increasingly valuable research and business tool.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / In this study different methods for speciation of Sb(III) and Sb(V) in meglumine antimoniate (NMG) were evaluated. Liquid chromatography (LC) combined or not with hydride generation (HG) was investigated for separation of Sb(III) and Sb(V). Inductively coupled plasma mass spectrometry (ICP-MS) was used as detector. A flow injection system together with hydride generation (FI-HG) coupled with atomic absorption spectrometry (AAS) was also employed for the selective determination of Sb(III) in presence of Sb(V). Two anion-exchange columns (Dionex, IonPacAS14 and Hamilton, PRP-X100) were evaluated for Sb(III) and Sb(V) separation by LC. Parameters related to the mobile phase, such as type (EDTA, potassium phthalate, and potassium phthalate + EDTA), concentration (0.5 to 10 mmol L-1), pH (3.5 to 7.0), flow rate (0.25 to 1.75 mL min-1) and elution mode (isocratic and gradient) were studied. The volume of sample injected into the chromatograph was set at 200 μL. For the chromatographic separation, the mobile phase which led to improved separations of Sb(III) and Sb(V) was the EDTA in concentrations of 0.5 mmol L-1 and 1.0 mmol L-1 for the IonPac and PRP-X100 columns, respectively. The most appropriate parameters related to the FI-HG system were also evaluated and set, such as reductant of Sb(III) (NaBH4 0.1%, m/v), complexant of Sb(V) (10% m/v citric acid,), water as the sample carrier, analytical path (300 cm), volume of sample (100 μL), total flow rate of solutions (8.5 mL min-1) and flow rate of carrier gas (0.4 mL min-1). In order to identify and/or quantify the species of Sb present in the NMG, the samples were diluted in water only. Through the use of LC-ICP-MS it was only possible to quantify the Sb(V), whereas the presence of Sb(III) was not detected. The determination of Sb(III) was only possible through FI-HG AAS, FI-HG-ICP-MS and LC-HG-ICP-MS (by combination of conditions set for LC and FI-HG individually). Similar results for Sb(III) were obtained through the techniques FI-HG AAS and HGICP- MS. Thus, it was possible to quantify free Sb(III) and Sb(V), while probable compounds of Sb(III) and/or Sb(V) bound to NMG were observed but could not be identified and quantified, mainly because of lack of reference solutions and difficulty in separating the observed Sb species. The precision of methods for determination of Sb(III) and Sb(V) (expressed as relative standard deviation for 5 consecutive measurements) was about 9% and 3% respectively. As there were no certified reference materials to evaluate the accuracy of the developed methods, recovery tests of Sb(III) and Sb(V) were made, where they were in the range 96 to 101% for Sb(V) and 85 to 104% for Sb(III). Moreover, the results were compared with those obtained by official methods to quantify Sb(III), Sb(V) and Sb total in meglumine antimoniate. / Neste trabalho foram avaliados diferentes métodos para a análise de especiação de Sb(III) e Sb(V) em antimoniato de meglumina (NMG). Cromatografia a líquido (LC) combinada, ou não, com a técnica de geração de hidretos (HG) foi investigada para a separação de espécies de Sb. A espectrometria de massa com plasma indutivamente acoplado (ICP-MS) foi empregada como detector. Um sistema de injeção em fluxo (FI) em conjunto com HG (FI-HG) e acoplado à espectrometria de absorção atômica (AAS) foi também empregado para a determinação seletiva de Sb(III) na presença de Sb(V). Duas colunas de troca aniônica (Dionex, IonPacAS14 e Hamilton, PRP-X100) foram avaliadas para separar as espécies de Sb por LC. Parâmetros relacionados com a fase móvel, tais como tipo (EDTA, ftalato de potássio e EDTA + ftalato de potássio), concentração (0,5 a 10 mmol L-1), pH (3,5 a 7,0), vazão (0,25 a 1,75 mL min-1) e o modo de eluição (isocrático e gradiente) foram estudados. O volume de amostra injetada no cromatógrafo foi fixado em 200 μL. Para a separação cromatográfica, a fase móvel que levou a melhores separações de Sb(III) e Sb(V) foi o EDTA nas concentrações de 0,5 mmol L-1 e 1,0 mmol L-1, para as colunas IonPac e PRP-X100, respectivamente. Os parâmetros relacionados com o sistema FI-HG mais adequados foram também avaliados e escolhidos, tais como o redutor do Sb(III) (NaBH4 0,1%, m/v), complexante do Sb(V) (ácido cítrico 10%, m/v), a água como carregador da amostra, o percurso analítico (300 cm), volume de amostra (100 μL), a vazão total das soluções (8,5 mL min-1) e a vazão do gás de arraste (0,4 mL min-1). Para a identificação e/ou quantificação das espécies de Sb presentes no NMG, as amostras foram somente diluídas em água. Com o emprego de LC-ICP-MS foi possível quantificar somente o Sb(V), não sendo detectada a presença da espécie Sb(III). A determinação de Sb(III) foi somente possível mediante as técnicas FI-HG AAS, FI-HG-ICP-MS e LC-HG-ICP-MS (esta mediante combinação das condições ajustadas para LC e FI-HG individualmente). Resultados concordantes para Sb(III) foram obtidos mediante as técnicas FI-HG AAS e FI-HGICP- MS. Desta forma, foi possível quantificar Sb(III) e Sb(V) livres, enquanto que possíveis compostos de Sb(III) e/ou Sb(V) ligados ao NMG foram observados mas não puderam ser identificados e quantificados, principalmente por causa da falta de soluções de referência e dificuldade de separação das possíveis espécies de Sb observadas. A precisão dos métodos de determinação de Sb(III) e Sb(V) (expressa como desvio padrão relativo para 5 medições consecutivas) foi cerca de 9% e 3%, respectivamente. Como não havia materiais de referência certificados para avaliar a exatidão dos métodos desenvolvidos, foram feitos testes de recuperação de Sb(III) e Sb(V), sendo que as mesmas ficaram na faixa de 96 a 101% para o Sb(V) e de 85 a 104% para o Sb(III). Além disso, os resultados obtidos foram comparados com aqueles obtidos por métodos oficiais para a quantificação Sb(III), Sb(V) e Sb total no antimoniato de meglumina.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-08-25T20:22:44Z No. of bitstreams: 1 FuadMousseAbinaderJunior_TESE.pdf: 4950058 bytes, checksum: 8b460657822556678edafea893ba0d36 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-08-25T21:57:31Z (GMT) No. of bitstreams: 1 FuadMousseAbinaderJunior_TESE.pdf: 4950058 bytes, checksum: 8b460657822556678edafea893ba0d36 (MD5) / Made available in DSpace on 2016-08-25T21:57:31Z (GMT). No. of bitstreams: 1 FuadMousseAbinaderJunior_TESE.pdf: 4950058 bytes, checksum: 8b460657822556678edafea893ba0d36 (MD5) Previous issue date: 2015-08-21 / A crescente demanda por tr?fego de dados em redes de acesso de banda larga sem fio ? Internet requer tanto o desenvolvimento de novas tecnologias de acesso mais eficientes quanto que novas faixas de frequ?ncia do espectro eletromagn?tico sejam alocadas para este fim. A introdu??o de um grande n?mero de small cells em redes celulares aliado ? ado??o de forma complementar de tecnologias de Wireless Local Area Networks (WLAN) em faixas de espectro n?o-licensiadas tem se verificado como um dos conceitos mais promissores. Uma das alternativas dentro deste conceito ? a introdu??o de small cells Long Term Evolution (LTE) operando em espectro n?o-licensiado Industrial, Science and Medical (ISM) de 5Gigahertz (GHz), numa abordagem conhecida como Unlicensed LTE (LTE-U). No entanto, a tecnologia de acesso de banda larga sem fio IEEE 802.11 (Wi-Fi) j? se encontra bastante difundida e operando nessa faixa de espectro, o que pode acarretar problemas de desempenho derivados da coexist?ncia de ambas as tecnologias na mesma faixa de espectro. Al?m disso, existe a necessidade de melhorar a opera??o do Wi-Fi para que possa suportar cen?rios com um grande n?mero de redes vizinhas, cada uma com um grande n?mero de n?s (conhecido como "?implanta??o densa"?). ? sabido que o desempenho global das redes Wi-Fi cai de forma acentuada com o aumento de n?mero de d?s compartilhando o canal, e portanto mecanismos para aumentar sua efici?ncia espectral se fazem necess?rios. Este trabalho ? dedicado ao problema da coexist?ncia entre diferentes sistemas de acesso ? banda larga sem fio operando nas mesmas faixas de espectro n?o-licensiado, e como resolver esses problemas por meio de algoritmos de coordena??o distribu?dos. O problema da coexist?ncia entre redes diferentes (i.e. LTE e Wi-Fi) e o problema de coexist?ncia entre diferentes redes da mesma tecnologia (i.e. m?ltiplas Overlapping Basic Subscriber Sets (OBSSs) Wi-Fi) ? analisado qualitativamente e quantitativamente via simula??o sist?mica, e suas principais quest?es a serem enfrentadas s?o identificadas. Com base nisso, solu??es distribu?das de coordena??o s?o propostas e avaliadas via simula??o sist?mica tanto para o problema de coexist?ncia inter-tecnologias como para o problema de coexist?ncia intra-tecnologia. Os resultados das avalia??es indicam que as solu??es concebidas prov?m ganhos significativos ante uma situa??o de coexist?ncia sem coordena??o distribu?da. / The increasing demand for Internet data traffic in wireless broadband access networks requires both the development of efficient, novel wireless broadband access technologies and the allocation of new spectrum bands for that purpose. The introduction of a great number of small cells in cellular networks allied to the complimentary adoption of Wireless Local Area Network (WLAN) technologies in unlicensed spectrum is one of the most promising concepts to attend this demand. One alternative is the aggregation of Industrial, Science and Medical (ISM) unlicensed spectrum to licensed bands, using wireless networks defined by Institute of Electrical and Electronics Engineers (IEEE) and Third Generation Partnership Project (3GPP). While IEEE 802.11 (Wi-Fi) networks are aggregated to Long Term Evolution (LTE) small cells via LTE / WLAN Aggregation (LWA), in proposals like Unlicensed LTE (LTE-U) and LWA the LTE air interface itself is used for transmission on the unlicensed band. Wi-Fi technology is widespread and operates in the same 5 GHz ISM spectrum bands as the LTE proposals, which may bring performance decrease due to the coexistence of both technologies in the same spectrum bands. Besides, there is the need to improve Wi-Fi operation to support scenarios with a large number of neighbor Overlapping Basic Subscriber Set (OBSS) networks, with a large number of Wi-Fi nodes (i.e. dense deployments). It is long known that the overall Wi-Fi performance falls sharply with the increase of Wi-Fi nodes sharing the channel, therefore there is the need for introducing mechanisms to increase its spectral efficiency. This work is dedicated to the study of coexistence between different wireless broadband access systems operating in the same unlicensed spectrum bands, and how to solve the coexistence problems via distributed coordination mechanisms. The problem of coexistence between different networks (i.e. LTE and Wi-Fi) and the problem of coexistence between different networks of the same technology (i.e. multiple Wi-Fi OBSSs) is analyzed both qualitatively and quantitatively via system-level simulations, and the main issues to be faced are identified from these results. From that, distributed coordination mechanisms are proposed and evaluated via system-level simulations, both for the inter-technology coexistence problem and intra-technology coexistence problem. Results indicate that the proposed solutions provide significant gains when compare to the situation without distributed coordination.

Made available in DSpace on 2014-12-17T14:56:07Z (GMT). No. of bitstreams: 1 LeonardoRSC_DISSERT.pdf: 726277 bytes, checksum: d47bf4e8090a3b1fadc03b4c34ebecda (MD5) Previous issue date: 2011-12-19 / The use of wireless sensor and actuator networks in industry has been increasing past few years, bringing multiple benefits compared to wired systems, like network flexibility and manageability. Such networks consists of a possibly large number of small and autonomous sensor and actuator devices with wireless communication capabilities. The data collected by sensors are sent directly or through intermediary nodes along the network to a base station called sink node. The data routing in this environment is an essential matter since it is strictly bounded to the energy efficiency, thus the network lifetime. This work investigates the application of a routing technique based on Reinforcement Learning s Q-Learning algorithm to a wireless sensor network by using an NS-2 simulated environment. Several metrics like energy consumption, data packet delivery rates and delays are used to validate de proposal comparing it with another solutions existing in the literature / A utiliza??o das redes de sensores e atuadores sem fio nas plantas das ind?strias vem crescendo nos ?ltimos anos, trazendo v?rios benef?cios em rela??o aos sistemas cabeados, como flexibilidade na instala??o e manuten??o da rede. Tais redes consistem basicamente de um n?mero possivelmente grande de dispositivos sensores e atuadores pequenos e aut?nomos que possuem capacidade de comunica??o sem fio. Os dados coletados pelos sensores s?o enviados seja diretamente ou passando atrav?s de n?s intermedi?rios pela rede at? uma esta??o-base conhecida como n? sink. O roteamento nesse ambiente ? uma quest?o essencial j? que est? intimamente ligado ? efici?ncia energ?tica e consequentemente ao tempo de vida da rede. Este trabalho investiga a aplica??o de uma t?cnica de roteamento baseado no algoritmo Q-Learning de Aprendizagem por Refor?o a uma rede de sensores sem fio atrav?s de simula??es no ambiente NS-2. Diversas m?tricas como consumo de energia, taxa de pacotes entregues com sucesso e atrasos s?o utilizadas para validar a proposta comparando-a com outras solu??es existentes na literatura

The increasing growth of mobile devices in the whole world, and the forecasts for the coming years has been indicated by several reports. Nonetheless, this need for ubiquitous collaboration has brought new possibilities and challenges to the scientific community. Mobile Ad hoc Networks (MANETs) emerges in this scenario allowing devices to interconnect autonomously, without the need of a fixed infrastructure, in order to provide communication and information services. Due to such decentralization and the natural constraints of mobile devices, it remains, to this day, a challenge to provide efficient routing for MANETs. In this dissertation we propose new routing enhancements based on policies for MANETs running the HTR protocol. We consider the role(s) a user associated to a device performs within an organization. Hence our policies can guide the routing based on these roles. With this scheme we improve communication according to different business needs and scenario requirements. To this end, we propose a set of policies that affects the routing behavior and present four case studies to present each policy. Then we analyze two policies in terms of end-to-end delay, and nodes’ lifetime. Through simulation we evaluate these metrics while varying parameters such as the amount of nodes participating in the network, the mobility characteristics, and the number of traffic sources. Our results show that it is possible to achieve these goals without causing great impact on the average end-to-end delay and energy consumption, two important metrics in any MANET evaluation. We explore the results in several scenarios and detail our findings, which can provide a different perspective for future MANET applications. / Submitted by João Arthur Martins (joao.arthur@ufpe.br) on 2015-03-10T18:42:15Z No. of bitstreams: 2 Dissertação Gabriela Coutinho.pdf: 1701782 bytes, checksum: 113328c2efdd1ba97f7a237d03cab574 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-11T17:46:06Z (GMT). No. of bitstreams: 2 Dissertação Gabriela Coutinho.pdf: 1701782 bytes, checksum: 113328c2efdd1ba97f7a237d03cab574 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2013-09-13 / O crescimento das vendas de aparelhos móveis em todo o mundo, bem como as previsões para os próximos anos são apontadas em diversos relatórios. No entanto, essa necessidade de colaboração ubíqua trouxe novas possibilidades e desafios para a comunidade científica. Redes móveis ad hoc (Mobile Ad hoc Networks - MANETs) surgem diante deste cenário e permite que dispositivos se comuniquem de forma autônoma, sem a necessidade de uma infraestrutura predefinida para fornecer comunicação e serviços. Porém, essa descentralização junto com as restrições naturais dos dispositivos móveis, proporcionar roteamento eficiente para MANETs permanece um desafio. Este trabalho propõe novas melhorias para o roteamento em MANETs que utilizam o protocolo HTR. Também considera o papel que usuários associados aos dispositivos desempenham dentro de uma organização. Desta forma, as políticas desenvolvidas podem guiar o roteamento também com base nestes papéis. Com este esquema, é possível melhorar a comunicação de acordo com necessidades de negócio e requerimentos de cenário. Para este fim, esta dissertação propõe um conjunto de políticas que afetam o comportamento do roteamento e analisa os impactos em termos de atraso, energia gasta e tempo de vida dos nós. Através de simulações, essas métricas são avaliadas também com variação de parâmetros como a quantidade de nós que participam da simulação, as características de mobilidade e o número de fontes de tráfego. Resultados mostram que é possível atingir esses objetivos sem causar grande impacto negativo no atraso fim a fim e no consumo de energia, duas métricas importantes em avaliações de redes MANET. Nós exploramos esses resultados em diversos cenários e detalhamos nossas descobertas, que podem servir como uma perspectiva diferente para futuras aplicações de redes MANET.

Feminist Science Fiction: Cherie Priest's The Clockwork Century Diploma Thesis Petra Nováková Abstract Marleen S. Barr, one of the pioneers of feminist science fiction criticism, is an outspoken commentator on gender inequality in this genre. In Feminist Fabulation: Space/Postmodern Fiction and Future Females: A Critical Anthology, Barr defines feminist science fiction as metafiction about patriarchal fiction. She speaks out against both authors and critics who recycle narratives restricted by a patriarchal view of the world in which women are silenced and/or relegated to the position of an accessory of the male hero, made to behave in a stereotypically feminine manner. While Barr does not include steampunk fiction but focuses on science fiction oriented towards the future and space exploration, her analysis of the female character's plight is nonetheless applicable to the steampunk genre. In this respect, feminist steampunk fiction can be read as a meditation on established gender norms. Cherie Priest's work is a prime example of such an innovative re-examination of gender stereotypes that Barr calls for in her critical work. As both a woman and a writer of science fiction, the author has adopted a feminist approach in her steampunk series The Clockwork Century. Among other things, Priest examines the role...