Dissertations / Theses on the topic 'Timing anomalies'

With the increasing dependence on Wireless Local Area Networks (WLANs), businesses and educational institutions are in real need of a robust security mechanism. The latest WLAN security protocol, the IEEE 802.11i assures rigid security for wireless networks with the support of IEEE 802.1x protocol for authentication, authorization and key distribution. Nevertheless, users remain skeptical since they lack confidence on the practical trustworthiness of these security mechanisms. In this research we propose a novel Early Warning System (EWS), built on the foundations of IEEE 802.11i security architecture. Our proposed system can effectively detect anomalies, substantiate them, and also identify the basis for such malicious behavior. It has a number of levels of defense to scrutinize malicious behaviors of the wireless network, caused by a range of factors including security issues. Security alerts will be raised only when the legitimacy of abnormal conditions is validated using effective outlier based substantiation techniques. Timing anomalies can occur due to various conditions including security vulnerabilities in the wireless environment. Hence, detecting and analyzing such anomalies may lead to significant advancement towards the detection of misbehaving wireless hosts. In this view, we have discussed the effectiveness of monitoring and analyzing round trip timing values between every request and response messages during the authentication process of wireless hosts. Further, to enhance the capabilities of our detection mechanism we have also considered the effect of behavioral anomalies of the wireless hosts. Every wireless host that tends to connect to the wireless network exhibits a particular behavior. This behavior may vary depending on a number of issues including security vulnerabilities. Hence, in this study we have discussed the use of behavioral analysis for detecting abnormal conditions. We have used the standard theoretical/practical behavior profiles developed using a software model of the wireless hosts to compare the actual behavior during a specific authentication process.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Information and Communication Technology
Science, Environment, Engineering and Technology
Full Text

According to Dimson (1998), modem financial theory is founded on the assumption that markets are highly efficient. The presence of anomalous stock market behaviour has therefore attracted a great amount of research internationally. This thesis investigates the presence and exploitability of style anomalies on the London Stock Exchange (LSE) and is divided into three main branches of research.

Includes bibliographical references.
A growing body of empirical evidence has found inconsistencies in the Capital Asset-pricing Model (CAPM) of Sharpe (1964), Lintner (1965), and Black (1972) and Ross's (1976) Arbitrage Pricing Theory (APT). Numerous attempts to explore the validity of these theories of modern finance have led to the identification of various firm specific attributes that explain the cross-sectional variation of returns. These attributes have appropriately been termed 'style anomalies '.This thesis investigates the existence and exploitability of style anomalies for the shares comprising the Toronto Stock Exchange (TSX) for the period 31 January 1989 to 31 July 2005. The investigation is divided into four areas of research. First, a methodology similar to Fama and Macbeth (1973) is used to explore the cross-sectional relationships between some 904 firm-specific attributes and the unadjusted and risk adjusted monthly returns of equities constituting the S&P TSX Composite Index. A myriad of uncorrelated style anomalies are found to persist before and after controlling for systematic risk, and are categorized as either size, growth, momentum, value, liquidity and bankruptcy (risk) effects. The most significant attributes from each respective style group include: Price, eighteen month change in net tangible asset value, price change over twelve months, twelve month change in price to net tangible asset value, three month change in the absolute volume ratio and interest cover before tax. Multivariate testing confirms the ability of anomalies to explain excess returns. In and out sample cross sectional tests show inconsistent anomaly persistence, raising the question of whether they are perhaps perennial in nature. Second, the predictability of style payoffs is examined through the analysis of autocorrelation and six style timing models. Strong positive autocorrelation at lower orders for the majority of style payoffs suggests that the ability to time payoffs is possible. The six month moving average timing model shows the best forecasting skill, followed by twelve month and eighteen month moving average models. Third, the presence of firm specific attributes among three classified sectors namely: Basic materials, Cyclicals and Non-Cyclicals are compared. Risk, value and liquidity based anomalies dominate the Basic Materials shares. Liquidity effects stand out within the Cyclicals group, and the Non-Cyclicals sectors exhibit value and size effects. The ability to exploit all style-based anomalies after accounting for transaction costs is evaluated using a portfolio sorting methodology. The tests illustrate that increased exposure to the anomalies has delivered substantially higher returns with lower volatility than a buy and hold approach using an equally weighted all share benchmark. These abnormal returns are confirmed after adjusting for systematic risk. Further testing shows that the attributes, rather than loading on those attributes, are better at explaining share returns. Finally, the seasonal nature of Canadian equity returns is investigated. A six month strategy of "Selling in June and going away till December" provides the most optimal returns. The calendar month tests find January, February and December to be the strongest months of the year. Attribute payoffs seem to show vague seasonal tendencies.

Les systèmes temps-réel sont souvent validés par des analyses temporelles, qui sont mises en péril par des anomalies temporelles (AT). Une AT contre-intuitive a lieu quand une accélération locale conduit à un ralentissement global, et une AT d'amplification, quand un ralentissement local entraîne un ralentissement encore plus grand.Alors que les AT contre-intuitives menacent le bien-fondé ou la flexibilité des analyses, il n'existe pas d'outils pour les détecter de manière systématique. Nous proposons une structure formelle unifiée pour évaluer les définitions des AT, concluant au manque d'une définition pratique, principalement dû à l'absence de relations entre les effets temporels locaux et globaux. Nous y répondons par la causalité, que nous utilisons pour revoir la formalisation de ces AT. Nous proposons aussi une instance des notions spécialisée pour les pipelines out-of-order. Nous évaluons notre procédure de détection subséquente sur des exemples illustratifs et bancs de tests, montrant qu'elle permet de capturer précisément les AT.La complexité des systèmes exige que leurs analyses gèrent l'important espace d'états résultant. Une solution est de réaliser des analyses compositionnelles, précisément menacées par les AT d'amplification. Nous faisons progresser leur étude en montrant comment une abstraction spécialisée peut être adaptée pour un processeur industriel, en modélisant les caractéristiques temporelles clés avec des réductions appropriées. Nous illustrons aussi à partir de cette classe d'AT comment des stratégies de vérification peuvent être utilisées en vue de l'obtention de motifs d'AT
The timing behavior of real-time systems is often validated through timing analyses, which are yet jeopardized by execution phenomena called timing anomalies (TAs). A counter-intuitive TA manifests when a local speedup eventually leads to a global slowdown, and an amplification TA, when a local slowdown leads to an even larger global slowdown.While counter-intuitive TAs threaten the soundness/scalability of timing analyses, tools to systematically detect them do not exist. We set up a unified formal framework for systematically assessing the definitions of TAs, concluding the lack of a practical definition, mainly due to the absence of relations between local and global timing effects. We address these relations through the causality, which we further use to revise the formalization of these TAs. We also propose a specialized instance of the notions for out-of-order pipelines. We evaluate our subsequent detection procedure on illustrative examples and standard benchmarks, showing that it allows accurately capturing TAs.The complexity of the systems demands that their timing analyses be able to cope with the large resulting state space. A solution is to perform compositional analyses, specifically threatened by amplification TAs. We advance their study by showing how a specialized abstraction can be adapted for an industrial processor, by modeling the timing-relevant features of such a hardware with appropriate reductions. We also illustrate from this class of TAs how verification strategies can be used towards the obtainment of TA patterns

In the last years, thanks to new generation satellites (mostly Chandra and XMM-Newton), an increasing number of high resolution spectral and timing observations of X-ray emitting isolated neutron stars (INS)has become available. Several new classes of X-ray emitting INSs have been discovered, all of them radio silent or with radio properties much at variance with those of Pulsar Radio (PSRs): X-ray Dim Isolated Neutron Stars (XDINSs), Anomalous X-ray Pulsars (AXPs) and Soft Gamma-ray Repeaters (SGRs), Central Compact Objects (CCOs), Rotating Radio Transient (RRATs, in one case). AXPs and SGRs represent two peculiar groups of INSs, totalling 15 objects (6 SGRs and 9 AXPs plus one candidate). Although much less noumerous than PSRs, these objects have been extensively studied because of their peculiar and extreme properties. SGRs exhibit bursts and flares with intensity between $\sim 10^2$ and $\sim 10^{11}$ times their quiescent X-ray luminosity ($10^{34} - 10^{36} \ {\rm erg/s})$. In the last decade transient phenomena have been observed from few AXPs, with luminosity increases between few 10 and few 100 times the X-ray quiescent values. The many similarities in the timing and spectral properties among SGRs and AXPs led to the suggestion that they could be two different manifestations of the same phenomenon. These objects are believed to host a Magnetar, an ultra-magnetized neutron star with magnetic field $\sim 10^{14}-10^{15}$ G. In the Magnetar model emission from SGRs and AXPs comes to the expanse of the ultra strong magnetic field rather than of the rotational, gravitational or thermal energy. In Magnetars the external magnetic field can acquire a toroidal component as a consequence of the deformation of the star crust induced by the super-strong internal field. As a result the star magnetosphere twists up and the currents required to support the non-potential field may provide a large enough optical depth to resonant cyclotron scattering (RCS). As a consequence a distortion in the thermal spectra emitting by the star surface is expected, because primary photons gain energy in the repeated scattering with the magnetospheric charges. Spectra emerging from a twisted magnetosphere in presence of RCS has been investigated by several authors (Lyutikov and Gavriil, 2006, Fernandez and Thompson, 2007, Nobili Turolla and Zane, 2008) and applied to SGRs and AXPs spectra by Rea et al. 2008 and Zane et al., 2008. The NTZ model 3D montecarlo simulation is the more advanced tool to compute both lightcurves and spectra. Resulting spectra are described in terms of 5 parameters: the twist angle $\Delta \phi$, the electron bulk velocity $\beta$, the surface temperature $T$ and the two geometrical angles$\xi$ and $\chi$($\xi$ is the misalignement between spin and magnetic axis while $\chi$ is the line of sight inclination with respect to the spin axis). In this thesis the application of NTZ model to two Transient AXPs XTE J1810-197 and CXOU J164710.2-455216 is discussed. XTE J1810-197 exhibited an outburst in late 2002 - early 2003, increasing its luminosity by two orders of magnitude. After the outburst onset the source has been monitored by XMM-Newton between September 2003 and September 2007, showing a decrease in flux until the pre-outburst value has been reached. CXOU J164710.2-455216 exhibited an outburst on 21 September 2006, when it was observed at a luminosity 300 times greater than that measured just five days before. The source has been observed by XMM-Newton 6 times after the outburst onset, between September 2006 and August 2009. In this work, adapted from Albano et al., 2010 paper, a comprehensive study of the pulse profile and spectral evolution of the two TAXPs following their outbursts onsets is presented. By confronting timing data with synthetic lightcurves obtained from the twisted magnetosphere model (Nobili, Turolla and Zane, 2008), we were able to estimate how the physical parameters of the source (surface temperature and emitting area, electron energy, twist angle) evolve in time. The fits of the pulse profiles also allowed us to infer the geometry of the two systems, i.e. the angles between the magnetic and rotational axes and the line of sight. Spectral models, obtained with the parameter values derived for the timing analysis, provide acceptable fits to XMM-Newton data.
Negli ultimi anni, grazie alla nuova generazione di satelliti (in particolare Chandra e XMM-Newton), è divenuto possibile osservare, con alta risoluzione, un crescente numero di stelle di neutroni isolate (INSs) che emettono raggi X. Molte nuove classi di INSs che emettono raggi X sono state scoperte, nessuna delle quali emette nel radio, o con proprietà nel radio in disaccordo con quelle delle PSRs: X-ray Dim Isolated Neutron Stars (XDINSs), Anomalous X-ray Pulsars (AXPs) e Soft Gamma-ray Repeaters (SGRs), Central Compact Objects (CCOs), Rotating Radio Transient (RRATs, in un caso). AXPs e SGRs sono due gruppi di INSs con caratteristiche peculiari, formati in tutto da 15 oggetti (6 SGRs e 9 AXPs più una candidata). Anche se meno numerose delle PSRs, questi oggetti sono stati ampiamente studiati proprio in virtù delle loro proprietà peculiari ed estreme. Gli SGRs mostrano bursts e flares con intensità tra le $\sim 10^2$ e le $\sim 10^{11}$ volte la loro luminosit\`a quiescente in banda X ($10^{34} - 10^{36} \ {\rm erg/s}$). Nell'ultima decade fenomeni spettrali transienti sono stati osservati in alcune AXPs, con un aumento di luminosità compreso tra alcune decine e alcune centinaia di volte la luminosità di quiescenza. Le molte similarità nelle proprietà spettrali e di timing di SGRs e AXPs portano a suggerire che questi oggetti possano essere nient'altro che differenti manifestazioni dello stesso fenomeno. Si ritiene che queste sorgenti ospitino una Magnetar, una stella di neutroni ultra magnetizzata con campo magnetico pari a $\sim 10^{14}-10^{15}$ G. Nel modello Magnetar l'emissione da SGRs e AXPs proviene dall'espansione del campo magnetico ultra intenso piuttosto che ad energie di tipo rotazionale, gravitazionale o termico. Nelle Magnetars il campo magnetico esterno potrebbe acquisire una componente di tipo toroidale, come conseguenza della deformazione della crosta della stella indotta dall'intensissimo campo magnetico interno. Il risultato netto è un twist della magnetosfera della stella; inoltre le correnti richieste per supportare il campo non potenziale potrebbero dar luogo ad una profondità ottica sufficientemente spessa per il resonant cyclotron scattering (RCS). Di conseguenza ci si aspetta una distorsione negli spettri termici, dato che i fotoni primari guadagnano energia nei ripetuti urti con le particelle cariche presenti nella magnetosfera. Gli spettri all'uscita della magnetosfera twistata in presenza di RCS sono stati studiati da svariati autori (Lyutikov e Gavriil, 2006, Fernandez e Thompson, 2007, Nobili Turolla e Zane, 2008) e questo modello è stato applicato agli spettri di SGRs e AXPs da Rea et al. 2008 and Zane et al., 2008. Il codice montecarlo 3D creato da Nobili, Turolla e Zane (2008) è lo strumento più avanzato per calcolare curve di luce e spettri. Gli spettri così ottenuti possono essere descritti in termini di 5 parametri: l'angolo di twist $\Delta \phi$, la velocità di bulk degli elettroni $\beta$, la temperatura superficiale $T$ e i due angoli geometrici $\chi$ e $\xi$ ($\xi$ è il disassamento tra campo magnetico e asse di rotazione mentre $\chi$ è l'inclinazione della linea di vista rispetto all'asse di rotazione). In questo lavoro, riadattato dall'articolo Albano et al., 2010, viene presentato un ampio studio dei profili pulsati e dell'evoluzione spettrale delle due TAXPs a partire dall'inizio dell'outburst. Confrontando i dati di timing con le curve di luce sintentiche ottenute con il modello di magnetosfera twistata (Nobili, Turolla e Zane, 2008) siamo stati in grado di stimare l'evoluzione temporale del parametri fisici della sorgente (temperatura superficiale e area emittente, energia degli elettroni, angolo di twist). I fit del profilo pulsato ci permettono anche di asserire la eometria del sistema, e cioè l'angolo fra campo magnetico e asse di rotazione e quello tra asse di rotazione e linea di vista. I modelli spettrali, ottenuti dai valori dei parametri derivati dall'analisi di timing, danno dei fit accettabili dei dati di XMM-Newton.

Les analyses statiques de pire temps d’exécution sont utilisées pour garantir les délais requis pour les systèmes critiques. Afin d’estimer des bornes précises sur ces temps d’exécution, ces analyses temporelles nécessitent des considérations sur la (micro)- architecture. Habituellement, ces modèles de micro-architecture sont construits à la main à partir des manuels des processeurs. Cependant, les initiatives du matériel libre et les langages de description de matériel de haut niveau (HCLs), permettent de réaborder la problématique de la génération automatique de ces modèles de micro-architecture, et plus spécifiquement des modèles de pipeline. Nous proposons un workflow qui vise à construire automatiquement des modèles de chemin de données de pipeline à partir de conceptions de processeurs décrites dans des langages de contruction de matériel (HCLs). Notre workflow est basé sur la chaine de compilation matériel Chisel/FIRRTL. Nous construisons au niveau de la représentation intermédiaire les modèles de pipeline du chemin de données. Notre travail vise à appliquer ces modèles pour prouver des propriétés liées à la prédictibilité temporelle. Notre méthode repose sur la vérification formelle. Les modèles générés sont ensuite traduits en modèles formels et intégrés dans une procédure existante basée sur la vérification de modèles pour détecter les anomalies de temps. Nous utilisons le langage de modélisation et de vérification TLA+ et expérimentons notre analyse avec plusieurs processeurs RISC-V open-source. Enfin, nous faisons progresser les études en évaluant l’impact de la génération automatique à l’aide d’une série de critères synthétiques
Static worst-case timing analyses are used to ensure the timing deadlines required for safety-critical systems. In order to derive accurate bounds, these timing analyses require precise (micro-)architecture considerations. Usually, such micro-architecture models are constructed by hand from processor manuals.However, with the open-source hardware initiatives and high-level Hardware Description Languages (HCLs), the automatic generation of these micro-architecture models and, more specifically, the pipeline models are promoted. We propose a workflow that aims to automatically construct pipeline datapath models from processor designs described in HCLs. Our workflow is based on the Chisel/FIRRTL Hardware Compiler Framework. We build at the intermediate representation level the datapath pipeline models. Our work intends to prove the timing properties, such as the timing predictability-related properties. We rely on the formal verification as our method. The generated models are then translated into formal models and integrated into an existing model checking-based procedure for detecting timing anomalies. We use TLA+ modeling and verification language and experiment with our analysis with several open-source RISC-V processors. Finally, we advance the studies by evaluating the impact of automatic generation through a series of synthetic benchmarks

In this thesis, we present the spectral and timing variabilities of anomalous X-ray pulsar 1E 2259+586 observed with European Photon Imaging PN Camera (EPIC PN) on board X-ray Multi Mirror Mission (XMM), Proportional Counter Array (PCA) on board Rossi X-ray Timing Explorer (RXTE) and Advanced CCD Imaging Spectrometer (ACIS) on board Chandra X-ray Observatory. We presented the results of spectral analysis of 2000 January 11 ACIS observation. Pulse phase spectroscopy was performed on two XMM observations before and after the outburst. Pulse profiles of two XMM observations before the outburst and three XMM observations after the outburst were studied. Results are consistent with the those presented by Patel et al. (2001) and Woods et al. (2004). We searched for the spectral variations versus spin rate during the outburst. Long-term spectral, frequency and spin-down rate variations are presented between 1996 and 2006 including 98 RXTE and 4 XMM observations. However, except outburst region (Woods et al. 2004) no significant spectral and spin rate variabilities were seen. Around the outburst region we confirmed the spectral hardening with increasing spin rate and flux.

Sebbene lo Standard Model (SM) descriva con grande successo le interazioni fondamentali della materia, esso non fornisce la risposta a diverse domande ancora aperte nella fisica fondamentale tra cui la natura della materia oscura, il problema della gerarchia delle interazioni fondamentali e non fornisce un modello quantistico della gravitazione. Per questo motivo diversi modelli mirano a completare lo SM (modelli con extra dimensioni, modelli super-simmetrici, ...). Denominatore comune di questi modelli (denominati generalmente BSM) è la predizione dell'esistenza di nuove particelle di massa dell'ordine di 1 TeV. La ricerca di produzione di risonante di bosoni o fermioni nelle collisioni protone-protone a LHC è una verifica diretta di questi modelli. La produzione risonante di coppie di fotoni può sondare l'esistenza di bosoni di spin-0, spin-2. L'eccellente risoluzione che è possibile raggiungere sulla misura della massa invariante dei due fotoni, e la segnatura peculiare del processo, permettono di cercare un picco di segnale nello spettro di massa continuo prodotto da processi descritti dallo SM. La risoluzione sulla massa invariante del sistema dei due fotoni è determinata da due fattori: la risoluzione energetica sui singoli fotoni e l'efficienza nella ricostruzione del corretto vertice di interazione da cui originano i fotoni. La ricerca è stata condotta sui dati raccolti in collisioni protone-protone a 13 TeV effettuate da LHC durante il 2016 (luminosità integrata pari a 35.9fb$^{-1}$). L'aumento dell'energia disponibile nel centro di massa della collisione ha permesso di esplorare una regione dello spettro più ampia di quella analizzata nelle ricerca in collisioni a 8TeV raccolti nel periodo 2011-2012. I risultati ottenuti non hanno evidenziato nessuna deviazione rispetto alla previsione del SM. Sono stati quindi fissati dei limiti di esclusione sulle sezioni d'urto per la produzione di gravitoni del tipo previsto dai modelli Randall-Sudrum I limiti variano tra tra 10fb e 1fb a seconda della massa prevista nell'intervallo $0.5 \mbox{TeV} < m < 4 \mbox{TeV}$. I risultati sono compatibili con le osservazioni dell'esperimento ATLAS. Il programma di LHC prevede una fase ad alta luminosità che inizierà nel 2026 durante la quale il complesso di acceleratori del CERN verrà migliorato fino a raggiungere una luminosità istantanea di $7.5\times10^{34}\mbox{cm}^{-2}\mbox{s}^{-1}$, cinque volte maggiore rispetto a quella raggiunta attualmente. A questo rinnovamento degli acceleratori sarà associata una revisione degli esperimenti che prevede il miglioramento dei rivelatori già esistenti e l'installazione di nuovi. Ai benefici indotti dall'aumento del numero di eventi disponibili per le analisi si oppone un generale degredamento della ricostruzione a causa dell'alto numero di collisioni che avverranno simultaneamente. Per mitigare questo fenomeno e per massimizzare l'accettanza ai canali di interesse per le misure di fisica CMS sta programmando un serie di interventi al rivelatore. Tra questi l'introduzione della misura di tempo nella ricostruzione richiede la costruzione ed installazione di un rivelatore di particelle cariche con risoluzione termporale di 30~ps. La tecnologia grazie ad una serie di test condotti con fasci di particelle in cui è stato anche dimostrato che l'attuale calorimetro elettromagnetico di CMS, con un opportuno miglioramento dell'elettronica di lettura, può raggiungere una risoluzione di 30~ps per energie maggiori di 20~GeV. Lo studio per la definizione del rivelatore è accompagnato da studi di simulazione volti a evidenziare il guadagno indotto dall'uso del tempo nella ricostruzione degli eventi. Questi studi hanno dimostrato un generale miglioramento nell'efficienza di ricostruzione di osservabili di interesse per la fisica che verrà esplorata nella fase ad alta luminosità.
Although the Standard Model of particle physics (SM) describes with extreme success the fundamental interactions of matter it does not provide a solution for open questions of modern physics. The nature of cosmological dark matter, a quantum description of gravity and the hierarchy problem cannot included in the framework of the SM. For this reason several extensions have been proposed throughout the years to address these open problems. The beyond the standard model (BSM) frameworks often predict the existence of additional particles, either arising from additional symmetries introduced by the model or by the inclusion of gravity. Part of the parameter space of these models can be covered by experiments at LHC, since the predicted particles can have masses in the TeV range. The diphoton resonant production is sensitive to spin-0 and spin-2 BSM resonances. These can be originated by wrapped extra dimensions or extension of the Higgs sector which are typically included in BSM models. The excellent energy resolution achieved with the CMS electromagnetic calorimeter (ECAL) and the clean signature of the dipho- ton events makes this channel very attractive as a tool for the search of exotic resonances. The sensitivity of the search in the diphoton channel is subordinated to the ECAL energy resolution and the precision on the location of the interaction vertex. The search pre- sented in this work has been conducted on data collected by the CMS experiment at LHC with proton-proton collisions at a center-of-mass energy of 13 TeV, for a total integrated luminosity of 35.9fb −1 . No significant deviation from the Standard Model prediction has been highlighted by the analysis, thus exclusion limits on the graviton production cross- section have been established in the context of the Randall-Sundrum extra dimensions model. The limits varies between 6 fb and 0.1 fb depending on the mass and coupling of the resonance in the 0.5 < m < 4.5 TeV and 0.01 < κ < 0.2 ranges. The LHC program foresees an high luminosity phase starting from 2026 (HL-LHC), during which the instantaneous luminosity will reach the record value of 7.5×10 34 cm −2 s −1 , five times the current one. On one hand higher instantaneous luminosity will bring benefits to the physics analysis by providing a dataset 10 times larger than what will be available during the LHC phase but, on the other hand will pose severe challenges to the event reconstruction given the high number of overlapping collisions. CMS is already planning various actions and detector upgrades to match the physics goal of HL-LHC. Among those the introduction of time into the event reconstruction will require the installation of a completely new detector. Technologies suitable for the measurement of charged particles time with a precision of 30 ps have been identified through a series of tests with particles beam. In the same tests the intrinsic time resolution of the ECAL has been proved to be better than 20 ps for electrons and photons of at least 25 GeV. The R&D campaign has been coupled to simulation studies to quantify the expected gain in performance provided by a time-aware event reconstruction. The simulation studies show a general improvement for observable of interest for the HL-LHC physics program.

In this thesis, the recently discovered Soft Gamma Ray Repeaters SGR J1833-0832, SWIFT J1822.3-1606 and SWIFT J1834.9-0846 are analysed using the archival Swift, RXTE, Chandra and XMM-Newton observations. The period fluctuations and timing noise properties of these sources are investigated. Spectral characteristics and long term frequency evolution of these sources are presented. Investigation for timing noise structure of these magnetars has shown a correlation between first frequency derivative of the spin frequency and torque noise strength.

We report on the long-term monitoring of five anomalous X-ray Pulsars (AXPs) using the Rossi X-ray Timing Explorer (RXTE ). We present a phase-coherent timing ephemeris for 4U 0142+61, and show that it has rotated with high stability over 4.4 yr, with RMS phase deviation of 7% of the pulse period from a simple fit including only n and n&d2; . We show that 1E 1048.1-5937 shows significant deviations from simple spin-down such that phase-coherent timing has not been possible over time spans longer than a few months. We find that the deviations from simple spin down are not consistent with single "glitch" type events, nor are they consistent with radiative precession. We suggest that 1E 1048.1-5937 may be a transition object between the soft gamma-ray repeater and AXP populations, and the AXP most likely to one day undergo an outburst. We also report on the continued timing stability of 1E 2259.1+586, for which phase coherence has now been maintained over 4.5 yr, as well as on the detection of a significant n&d3; in RXS J170849.0-400910, consistent with recovery following a glitch. We note a possible correlation in which timing stability decreases with increasing n&d2; . We find no large variability in pulse morphology as a function of time. We present high signal-to-noise ratio average pulse profiles for each AXP, and consider them as a function of energy. We find a variety of different behaviors, and consider possible trends in the data. We also find no large variations in pulsed flux, and set la upper limits of ∼20--30% of the mean.

Cette thèse présente une étude de la sensibilité à la physique au delà du modèle standard et en particulier aux couplages anormaux entre les photons et les bosons W. Ceci est réalisé en détectant dans ATLAS les protons intacts après interaction et en mesurant leur temps de vol avec une précision de quelques pico-secondes de part et d'autre du détecteur central.Je décrirai également les photo-détecteurs de grande superficie avec une précision de quelques pico-secondes et les algorithmes de reconstruction de temps basés sur l'échantillonnage rapide du signal. Le circuit intégré spécifique SamPic pour une mesure de temps de très haute précision sera enfin présenté ainsi que les premiers résultats de mesure avec ce circuit. Ils montrent en particulier une précision exceptionnelle, meilleure que 5 ps, sur la mesure de temps entre deux impulsions.