Mobile applications can benefit from increased awareness of the device's context. Unfortunately, existing solutions for inferring context require special purpose sensors or beacons on the mobile devices or in the physical environment. This requirement significantly limits the deployment of these solutions. In this thesis, I argue that mobile devices can infer a substantial amount of their context by leveraging their existing wireless interfaces to monitor ambient radio sources, such as GSM cell towers or WiFi access points. I focus on two important problems in context-aware computing: localization of mobile devices and detecting proximity between mobile devices for authentication purposes. Specifically, I present an accurate localization system based on fingerprinting of GSM signals. I show that the key to more accurate GSM localization is the use of wide signal strength fingerprints that include readings from a large number of base stations. Next, I present a method that addresses the key drawback of fingerprint-based localization systems - the need to collect extensive measurements to train the system in every target environment. Finally, I show how radio environment sensing can be used to secure the communication of devices that come within close proximity. Removing the need for additional hardware on the mobile devices and in the physical environment renders the approach that I present amenable for widespread deployment.

Pairing and synapsis of homologous chromosomes are required for normal chromosome segregation and the exchange of genetic material during meiosis. Pairing is defined as the recognition and alignment of chromosomes that occurs either pre-meiotically or during early prophase I to ensure that associations via synapsis and recombination occur only between homologues. Synapsis is the intimate juxtaposition of homologous chromosomes that is complete at pachytene following formation of a tri-partite proteinaceous structure known as the synaptonemal complex (SC). In yeast, HOP1 is an essential component of the SC that localises along chromosome axes during prophase I and promotes homologous chromosome interactions. Homologues in Arabidopsis (AtASY1), Brassica (BoASY1) and rice (OsPAIR2) have been isolated through analysis of mutants that display decreased fertility due to severely reduced synapsis of homologous chromosomes. Analysis of these genes has indicated that they play a similar role to HOP1 in pairing and formation of the SC through localisation to axial/lateral elements of the SC. In this study, we have characterised the bread wheat homologue of HOP1, TaASY1, and its encoded protein. The full length cDNA and genomic DNA clones of TaASY1 have been isolated, sequenced and characterised. TaASY1 is located on chromosome group 5 and the open reading frame displays significant similarity to OsPAIR2 (84%) and AtASY1 (63%). In addition to OsPAIR2 and AtASY1, the deduced amino acid sequence also displays sequence similarity to ScHOP1, with all four proteins containing a HORMA domain. Transcript and protein analysis showed that expression is largely restricted to meiotic tissue, with elevated levels during the stages of prophase I when pairing and synapsis of homologous chromosomes occurs. Antibodies specific to TaASY1 were used in immuno-fluorescence microscopy and immuno-gold transmission electron microscopy to investigate the localisation of TaASY1 in meiotic cells. Immuno-fluorescence analysis initially detected ASY1 in pollen mother cells (PMCs) during meiotic interphase as foci randomly distributed over the chromatin. The ASY1 signal became increasingly continuous during leptotene, reflecting the changes occurring in chromosome morphology. Throughout zygotene, the signal became progressively more continuous, localising along the entire length of the axial elements as chromosomes synapsed. This signal appeared to persist until pachytene, before disappearing from the chromatin as the SC disassociated through late pachytene and early diplotene. The immuno-gold based electron microscopy displayed that TaASY1 localises to chromatin that is associated with both axial elements before SC formation as well as chromatin of lateral elements within formed SCs. Analysis of RNAi Taasy1 mutants was performed to further define the role of ASY1 in bread wheat meiosis. ASY1 localisation was disrupted in these mutants, with a diffuse and non-continuous signal observed through leptotene and zygotene. Feulgen staining of meiotic chromosomes displayed reduced synapsis during prophase I, as well as multivalents at metaphase I and abnormal chromosome segregation during anaphase I. These observations are consistent with the presence of homoeologous chromosome interactions. TaASY1 expression and localisation was also investigated in the bread wheat pairing mutant, ph1b. Quantitative real-time PCR (Q-PCR) revealed that TaASY1 is significantly up-regulated in ph1b, with greater then 20-fold expression compared to wild-type Chinese Spring, while maintaining the same pattern of expression as wild-type through progressive stages of meiosis. ASY1 localisation was significantly disrupted in ph1b, with irregular loading on axial elements during mid to late zygotene, indicative of abnormal chromatin remodelling and multiple axial element associations that have previously been reported in ph1b. Taken together, these results indicate that TaASY1 is essential for promoting homologous chromosome interactions during meiosis, and that impairment of ASY1 function in bread wheat meiosis results in reduced restriction of chromosome associations to homologues. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1340087 / Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2008

Thesis (Ph. D.)--Kent State University, 2007. / Title from PDF t.p. (viewed July 15, 2008). Advisor: John W. Watson. Includes bibliographical references (p. 125-129).

L'objectif de ce travail est la généralisation, dans le contexte des 1-motifs, des accouplements de hauteurs construits par B. Mazur et J. Tate sur les variétés abéliennes. Suite à leur approche, nous considérons de ρ-splittings de la biextension de Poincaré d’un 1-motif et nous demandons qu'ils soient compatibles avec la linéarisation canonique associée à la biextension. Nous établissons donc des résultats concernant l'existence de tels ρ-splittings. Quand ρ est non-ramifié, celle-ci est garanti si l'accouplement de monodromie du 1-motif pris en considération est non-dégénéré. Pour ρ ramifié, le ρ-splitting se construit à partir d'une paire de scindages des filtrations de Hodge des réalisations de de Rham du 1-motif et de son dual. Ceci généralise des résultats précédents de R. Coleman and Y. Zarhin pour les variétés abéliennes. Ces ρ-splittings sont ensuite utilisés pour définir un accouplement global entre les points rationnels d'un 1-motif et de son dual. Également, nous fournissons des accouplements locaux entre les zéro-cycles et les diviseurs sur une variété, qui est fait en appliquant les résultats précédents à ses 1-motifs de Picard et d’Albanese. / The purpose of this work is to generalize, in the context of 1-motives, the height pairings constructed by B. Mazur and J. Tate on abelian varieties. Following their approach, we consider ρ-splittings of the Poincaré biextension of a 1-motive and require that they be compatible with the canonical linearization associated to the biextension. We establish results concerning the existence of such ρ-splittings. When ρ is unramified this is guaranteed if the monodromy pairing of the 1-motive considered is non-degenerate. For ramified ρ, the ρ-splitting is constructed from a pair of splittings of the Hodge filtrations of the de Rham realizations of the 1-motive and its dual. This generalizes previous results by R. Coleman and Y. Zarhin for abelian varieties. These ρ-splittings are then used to define a global pairing between rational points of a 1-motive and its dual. We also provide local pairings between zero cycles and divisors on a variety, which is done by applying the previous results to its Picard and Albanese 1-motives.

Stimulus Pairing Observational Procedure (SPOP) is an incidental teaching type procedure that has shown success in teaching typically developing children to name, independent tacting in the absence of the verbal community following a history of listener and echoic responses. The purpose of the current study was to compare SPOP and matching to sample procedures to determine the rate of acquisition for correct tact and listener responding , the rate of off task be avior, and the rate of generalization to different settings, stimuli, and instructors. Results of the study indicate that correct responding occurred at higher rates during MTS procedures than SPOP. The average rate of off task behavior was higher during SPOP sessions than during pre test, MTS sessions, or generalization probes for each participant. The results of the generalization probe may indicate that SPOP produces correct responding that increases or maintains during generalization, while MTS procedures produced more variable results.

With the the emergence of the Internet-of-Things (IoT) and Cyber-Physical Systems (CPS), modern computing is now transforming from residing only in the cyber domain to the cyber-physical domain. I focus on one important aspect of this transformation, namely shortcomings of traditional security measures. Security research over the last couple of decades focused on protecting data in regard to identities or similar static attributes. However, in the physical world, data rely more on physical relationships, hence requires CPS to verify identities together with relative physical context to provide security guarantees. To enable such verification, it requires the devices to prove unique relative physical context only available to the intended devices. In this work, I study how varying levels of constraints on physical boundary of co-located devices determine the relative physical context. Specifically, I explore different application scenarios with varying levels of constraints – including smart-home, semi-autonomous vehicles, and in-vehicle environments – and analyze how different constraints affect binding identities to physical relationships, ultimately enabling IoT devices to perform such verification. Furthermore, I also demonstrate that sensing may pose risks for CPS by presenting an attack on personal privacy in a smart home environment.

L'anneau de Grothendieck d'une structure a été défini par Tom Scanlon et Jan Krajicek d'une part, et François Loeser et Jan Dnf d'autre part. Il est obtenuà partir des ensembles définissables et des deux opérations d'union disjointe et de produit cartésien, en identifiant deux ensembles en bijection définissable.En nous appuyant sur des techniques mêlant topologie et combinatoire, nous montrons dans cette thèse, que les anneaux Z×Z, Z, Z[X], Z/NZ et (Z/NZ)[X] (pour N ∈ Z+) peuvent s'obtenir comme anneaux de Grothendieck de certaines structures.Dans une première partie, après avoir rappelé la construction des anneaux de Grothendieck et donné un bref aperçu de ceux déjà connus, nous préciserons le cadre d'application des techniques mises en œuvre dans les chapitres suivant.La deuxième partie est consacrée au calcul explicite de certains anneaux de Grothendieck.Nous montrons d'abord que Z×Z est l'anneau de Grothendieck des fonctions de paires sans cycles.Dans les chapitres suivants, nous proposons pour chaque anneau préalablement choisi une structure qui l'admette comme anneau de Grothendieck / The notion of Grothendieck ring of a structure has been introduced by Tom Scanlon et Jan Krajicek on the one hand. François Loeser and Jan Dnf on the other hand.This ring is obtained from the definable sets and from the operation of disjoint unions and cartesian product, by identifying the definable sets which are in definable bijection.By using thechnics involving topoligal ideas and combinatorics, we show thaht the rings Z×Z, Z, Z[X], Z/NZ et (Z/NZ)[X] (for N ∈ Z+) are the Grothendieck ring of some structures.In particular, Z×Z is the Grothendieck ring of the pairing function with no cycles.As for the other rings, we build construction specially designed to admit as Grothendick ring, the ring prealably chosen

La structure du noyau N = Z doublement magique 56Ni (N = 28, Z = 28) a été étudiée en mesurant les réactions de transfert á un et deux nucléons. Le transfert nous donne des informations sur deux aspects physiques différents: la fermeture de couche N=28 et l’intensité de l’appariement neutron-proton. Le nombre magique N=28 est particulier, car c’est le premier créé par le spin-orbit. La double magicité permet la détermination de la nature de particule indépendante des voisins N±1 par réaction de transfert d’un nucléon. De plus, en tant que noyau N=Z a couches fermeés, le 56Ni est un noyau clé pour l’étude de l’apparement np dans la plus grande couche accessible expérimentalement. L’apparement np se manifeste dans le canal isoscalaire (T=0) et isovecteur (T=1). L’intensité relative de chaque canal révèle la nature collective des états. L’expérience de ce travail a eu lieu au GANIL-Caen, en France, avec un faisceau radioactif de 56Ni á 30MeV / u produit par frag- mentation de 58Ni et purification avec le spectromètreLISE. Les mesures ont été effectuées en cinématique inverse sur des cibles CH2 et CD2. Les détecteurs MUST2 et TIARA ont été utilisés pour la détection de éjectiles légers et couvraient presque 4π. En outre, quatre détecteurs germanium d’EXOGAM ont été utilisés pour les coïncidences de particules-gamma afin d’identifier l’état peuplé du résidu de réaction. Pour étudier le gap de N=28, nous étudions la spectroscopie du 55Ni par les réactions de transfert de nucléons (d, t) et (p, d) sur le 56Ni. Le spectre en énergie d’excitation est déduit de la mesure des éjectiles légers seulement. Ensuite,les coincidences particule-gamma sont utilisées pour améliorer la résolution et identifier les principaux états peuplés. La comparaison des distributions angulaires ainsi obtenues avec des calculs DWBA permet d’extraire les facteurs spectroscopiques pour les états de particules et de trous ainsi peuplés. En ce qui concerne l’appariement np, nous avons analysé la réaction 56Ni(d,α)54Co qui réalise un transfert de paires neutron-proton. Un affaiblissement du canal T=0 á cause de l’effet du spin-orbite est attendu. La sélectivité en ∆T=0 de la réaction (d, α) permet d’étudier plus en détail le canal isoscalaire T = 0. / The structure of the unstable doubly ma- gic nucleus 56Ni has been investigated by measuring one- and two-nucleon transfer reactions. Each trans- fer reaction provides information for two different physical aspects: the robustness of the N=28 shell gap and the strength of the neutron-proton pairing. 56Ni is a self-conjugate doubly magic nucleus with N=28 and Z=28. The magic number 28 is a peculiar shell closure created by spin-orbit splitting effects. The double magicity makes the determination of the single-particle nature of their N±1 neighbors by one-neutron transfer reaction of major interest to test both the robustness of shell closures as well as the evolution of particle and/or valence orbitals. Moreover 56Ni, as a N=Z nucleus with fully closed shells, is a key nucleus to investigate neutron-proton pairing in the largest shell accessible experimentally, the fp shell. Neutron-proton pairing can occur both in the isoscalar (T=0) and in the isovector (T=1) channels. The relative intensity of both channels reveals the collective nature of the states. The radioactive beam of 56Ni was produced at GANIL-Caen, France at 30 MeV/u by fragmentation of 58Ni and purification with the LISE spectrometer. The experimental set-up used, consists of the TIARA- MUST2-EXOGAM combination which provides an al- most 4π coverage and the ability to perform particle- γ coincidences. To probe the N=28 gap, we studied the spectroscopy of 55Ni through one-nucleon trans- fer reactions on 56Ni. The excitation energy spectrum is deduced by measuring the light ejectiles only, while particle-γ coincidences are used to improve the re- solution of the populated states and select the main ones. Comparison in between the extracted angular distributions and DWBA calculations allow the extraction of the spectroscopic strength of the hole- and particle- states populated by these one neutron pick- up reactions. As for neutron-proton pairing, a weakening of the strength is expected in the T=0 channel from previous results. The selectivity in ∆T=0 of the 56Ni(d,α)54Co reaction enables further investigation of the isoscalar channel contribution.

Two applications of a binary tree data type based on a simple pairing function (a bijection between natural numbers and pairs of natural numbers) are explored. First, the tree is used to encode natural numbers, and algorithms that perform basic arithmetic computations are presented along with formal proofs of their correctness. Second, using this "canonical" representation as a base type, algorithms for encoding and decoding additional isomorphic data types of other mathematical constructs (sets, sequences, etc.) are also developed. An experimental application to a memory management system is constructed and explored using these isomorphic types. A practical analysis of this system's runtime complexity and space savings are provided, along with a proof of concept framework for both applications of the binary tree type, in the Java programming language.

Mobile devices have advanced tremendously during the last ten years and have changed our daily life in various ways. Secure pairing of mobile devices has become a significant issue considering the huge quantity of active mobile device connections and mobile traffic. However, current commonly used file sharing mobile applications rely on servers completely that are always targeted by attackers. In this thesis work, an innovative mechanism is proposed to generate symmetric keys on both mobile devices independently from a shared movement in arbitrary pattern, which means no server needs to be involved and no data exchange needed. A secret wireless-communication channel can then be established with a particular network strategy.