L’objectif principal de cette thèse vise la compréhension et la maitrise des mécanismes physiques menant à l’excitation du mode gyrotropique de vortex magnétique par transfert de spin, et en particulier l’origine des sources de bruit affectant sa dynamique. Ce travail est effectué dans la perspective de parvenir à l’amélioration des propriétés radiofréquences de ces dispositifs appelés Spin Transfer Oscillator.En effet, ces oscillateurs ont l’avantage d’être de taille submicronique (quelques dizaines à quelques centaines de nm), d’être compatibles avec les technologies CMOS et d’être résistants aux radiations. De plus, les mécanismes d’aimantation mis en jeu leur assurent une forte dépendance de la fréquence avec le courant, i.e. une bonne accordabilité, ainsi qu’une réponse dynamique rapide i.e. une agilité élevée. Cependant, différentes questions restent en suspens quant à la possibilité d’améliorer leurs conditions d’oscillations, leur puissance et la cohérence de leurs oscillations.Un premier aspect de mon travail de thèse a été d’étudier l’influence des fluctuations thermiques sur la dynamique entretenue du mode gyrotropique du cœur de vortex. Un des résultats a été de montrer que le bruit de phase du mode gyrotropique résulte majoritairement de fluctuations de phase issues directement des fluctuations thermiques auxquelles s’ajoutent des fluctuations d’amplitude converties en fluctuations de phase. Grâce à un modèle analytique, nous avons pu mettre en évidence le rôle important joué par les non-linéarités des forces agissant sur le vortex. De plus, nous avons pu mesurer les paramètres caractéristiques de l’oscillateur, à savoir, la rapidité à changer sa fréquence mais aussi le facteur de couplage amplitude-phase.La seconde étape de mes travaux a consisté à améliorer les conditions d’obtention de signal rf. Un résultat majeur de ce travail a été l’obtention d’un signal rf puissant en absence de champ magnétique. Les puissances mesurées sont de quelques centaines de µW correspondant à des largeurs de raie faibles allant de quelques centaines de kHz à quelques MHz. Cette spécificité est rendue possible pour une structure complexe de l’oscillateur où la couche magnétique qui polarise en spin le courant a une aimantation perpendiculaire et est différente de la couche de référence pour la magnétorésistance.La troisième étape a été d’optimiser le rendement de l’oscillateur. Un des résultats marquants est que nous avons pu mesurer une puissance rf émise record s’élevant à 3.6 µW, encore jamais obtenue à température ambiante pour les oscillateurs à transfert de spin à base de vortex. Ces fortes puissances résultent du développement de nouvelles jonctions à base de FeB effectués par le groupe de S. Yuasa (AIST, Japon) pour lesquelles l’amélioration de la qualité de la jonction, nous a permis d’obtenir une magnétorésistance atteignant 125% .La faible taille de l’oscillateur a donc un coût qui se paye en termes de bruit de phase. Une solution qui permettrait de résoudre cette limitation et d’améliorer la cohérence des oscillations est la synchronisation mutuelle de plusieurs oscillateurs à transfert de spin au travers des courants rf émis par chacun. Ainsi, la dernière étape de ma thèse a été d’étudier le comportement du mode gyrotropique lorsqu’il est soumis à un courant alternatif. Un résultat important a été de montrer, grâce à une étude expérimentale appuyée sur un modèle analytique, le rôle crucial des non-linéarités et des symétries des forces de synchronisation du mode excité.Ces différents travaux nous ont fournis les outils pour mieux comprendre la dynamique du vortex magnétique et nous ont amené à mettre en place un banc de mesure original pour lequel l’oscillateur se synchronise sur lui-même. En fonction du retard avec lequel le signal émis par l’oscillateur est réinjecté, nous avons pu montrer pour la première fois que la fréquence, la puissance mais aussi la largeur de raie des oscillations peuvent être modulées. / The main goal of this thesis is the understanding of the physical mechanisms and the subsequent control of the properties at the origin of the spin transfer induced magnetic vortex gyrotropic motion in confined systems. In particular the origin of the noise affecting the dynamics has been investigated. This work has been performed with a view to improving the radiofrequency (rf) properties of the so-called Spin Transfer Oscillator (STO).The advantages of such oscillators are their sub-micron size (from few tens to hundreds of nanometres), their compatibility with CMOS technologies and their radiation hardness. Moreover, the magnetization dynamics involved permit a large tunability of frequency as a function of the applied current and a high agility i.e. a fast dynamical response. Nevertheless, several open questions exist regarding the possible optimization of the sustained oscillation conditions and the improvement of the STO power and spectral coherence.The first aspect of my work was to investigate the influence of thermal fluctuations over the sustained vortex core gyrotropic motion. One of the key results of my thesis was to show that the phase noise results from direct phase fluctuations from thermal fluctuations plus amplitude fluctuations converted to phase noise. With an analytical model, we were able to highlight the major role played by the non-linearities of the forces acting on the vortex core. In addition, we were able to measure the characteristic parameters of the oscillator, namely, the speed of frequency response to perturbations as well as the phase-amplitude coupling coefficient.The second important part of my work has been to improve the conditions for obtaining an rf signal. An important result of this work was the measurement of a powerful rf signal in the absence of a magnetic field. The measured powers are a few hundred milliwatts and correspond to low linewidths, ranging from a few hundred kilohertz to a few megahertz. The zero field behaviour was made possible due to the complex structure of the oscillator where the magnetic layer which polarizes the spin current has a perpendicular magnetization, in contrast to the in-plane polarized reference layer.The third step was to optimize the performance of the oscillator. One of the striking results of this thesis is that we measured a record rf output power, up to 3.6 µW, the largest obtained at room temperature for vortex based STOs so far. This high output power results from the development of new FeB based junctions made by the group of Pr. S. Yuasa (AIST, Japan), where the improvement of the quality of the junction allowed us to obtain a magnetoresistance up to 125%.The small size of the oscillator has a cost that is paid in terms of the phase noise. One possible solution that would solve this limitation and enhance the coherence of the oscillations is via mutual synchronization of several STOs through rf currents emitted by each oscillator. Thus, the last stage of my thesis was to study the behaviour of gyrotropic motion when subjected to an alternating current. An important result was to show, through an experimental study in conjunction with an analytical model, the crucial role of the non-linearities and symmetries of the synchronization forces.These various studies have provided us the tools to better understand the dynamics of magnetic vortex and led us to develop an original tester for which the oscillator synchronizes itself with its own rf signal. Depending on the delay at which the oscillator is fed back, we showed for the first time that the frequency, the power and also the linewidth of the oscillations can be modulated.

No description available.

Die Arbeit ist der Weiterentwicklung der Formgebungs- und Verdichtungsausrüstungen zur Herstellung von Beton- und Stahlbetonrohren gewidmet. Es werden die Grundlagen für eine schwingungstechnische Auslegung von Betonrohrfertigern mit stehendem und steigendem Kern geschaffen. Den Ausgangspunkt bildet die Untersuchung des Verdichtungsprozesses in Rohrfertigern und der Einflußgrößen auf die Vibrationsverdichtung des Betongemenges. Es werden experimentelle Untersuchungen an einem Versuchsstand und praktische industrielle Erfahrungen dargestellt. Für die schwingungstechnische Auslegung der Verdichtungseinrichtung von Rohrfertigern werden diskrete Modelle mit analytischen Lösungen sowie Modelle zur numerischen Simulation auf der Basis der Mehrkörperdynamik und der Finite-Elemente-Methode gebildet. Es erfolgen Empfehlungen zur Auslegung und Ansätze zur Weiterentwicklung von Rohrfertiger.

There is a enormous rise in importance of cryptography. In age of hi-technologies, where information are the most valuable asset, is need to protect this value. But we need to transport information between us and keep information confidental. In this case we use special modes of block cipher because of defect in communication canal. Not all modes are able to deal with this problem. For this purpose, there are special modes. This work deal with self-synchronization modes of block cipher. It is protection of tranfered information in communication canal against different types of defects. We will exam two self-synchronization modes - OCFB (Optimized Cipher FeedBack) and SCFB (Statistical Cipher FeedBack). Both have their advantages and disadvantages. The goal of this work is to provide analyse of both modes and to create simulation model. This model should help with further research of self-synchronization modes.

Die Arbeit ist der Weiterentwicklung der Formgebungs- und Verdichtungsausrüstungen zur Herstellung von Beton- und Stahlbetonrohren gewidmet. Es werden die Grundlagen für eine schwingungstechnische Auslegung von Betonrohrfertigern mit stehendem und steigendem Kern geschaffen. Den Ausgangspunkt bildet die Untersuchung des Verdichtungsprozesses in Rohrfertigern und der Einflußgrößen auf die Vibrationsverdichtung des Betongemenges. Es werden experimentelle Untersuchungen an einem Versuchsstand und praktische industrielle Erfahrungen dargestellt. Für die schwingungstechnische Auslegung der Verdichtungseinrichtung von Rohrfertigern werden diskrete Modelle mit analytischen Lösungen sowie Modelle zur numerischen Simulation auf der Basis der Mehrkörperdynamik und der Finite-Elemente-Methode gebildet. Es erfolgen Empfehlungen zur Auslegung und Ansätze zur Weiterentwicklung von Rohrfertiger.

Approved for public release; distribution in unlimited. / Military leaders and scholars alike debate the existence of a revolution in military affairs (RMA) based on information technology. This thesis will show that the Information RMA not only exists, but will also reshape how we plan, operate, educate, organize, train, and equip forces for the 21st century. This thesis introduces the Communication Technology (CommTech) Model to explain how communication technologies affect organizations, leadership styles, and decision-making processes. Due to the growth in networking enterprises, leaders will have to relinquish their tight, centralized control over subordinates. Instead, they will have to perfect their use of softer power skills such as influence and trust as they embrace decentralized decision-making. Network Centric Warfare, Self-Synchronization, and Network Enabled Operations are concepts that provide the framework for integrating information technology into the battlespace. The debate that drives centralized versus decentralized control in network operations is analyzed with respect to the CommTech Model. A new term called Operational Trust is introduced and developed, identifying ways to make it easier to build trust among network entities. Finally, the thesis focuses on what leaders need to do to shape network culture for effective operations. / Major, United States Air Force

<p>So- called “Network Based Defense” (NBD) was introduced in Sweden in connection with the transformation of the Swedish Armed Forces in 1999. NBD is based on the U.S. variant Network Centric Warfare (NCW), which in turn is derived from research on the concept of Revolution in Military Affairs (RMA). In Sweden the concept was introduced and included not only the Armed Forces but was intended to also support the Swedish civilian agencies in order to create networks and hence share the available information and thus more effective crisis management and to provide more "bang for the buck." In developing the concept of NBD the Swedish Armed Forces used both economic and human resources, in the form of research, new technologies, new organization and new methods.</p><p>Between year 2004 and 2006 the Armed Forces once again entered the process of reorganization. This time to “classic” military hierarchical organization and NBD as development engine disappeared due to economic cutbacks, together with the decision to participate in the European Union (EU) rapid reaction force. The purpose of this essay is to study the theories and ideas behind the concept and why the concept "disappeared" a few years later. The result of the work suggests that the concept of NBD in its abstract form was too theoretical. The process of organization introduced by HKV -04 is the clearest example of this abstract ambiguity concerning command and responsibility. Research suggests that responsibility is the basis of military organization and operations. The results also shows that a number of experiences from the development of the NBD has been used in the more practically oriented transformation of the Armed Forces necessary by the commitments for the so- called Nordic Battle Group (NBG-08).</p><p>The results have also shown correlation between NBD development and the increased Nordic cooperation in the form of sea and air surveillance and the well-developed body interaction within the framework of the national crisis management capacity in Sweden.</p> / <p>Nätverks Baserat Försvar (NBF) infördes i Sverige inom ramen för transformationen av Försvarsmakten från ett invasionsförsvar till ett insatsförsvar. NBF bygger på den amerikanska varianten <em>Network Centric Warfare</em> (NCW) som i sin tur härstammar från forskningen kring begreppet <em>Revolution in Military Affairs</em> (RMA). Konceptet infördes och innefattade inte bara Försvarsmakten utan även stödmyndigheter i syfte att skapa ett nätverk och därmed dela tillgänglig information och därmed effektivisera krishanteringen och ge mer ”pang för pengarna”. Kring utvecklingen av konceptet NBF lades stora resurser i form av forskning, ny teknik, ny organisation och nya metoder.</p><p>År 2004 till 2006 omorganiserades Försvarsmakten återigen från införd processorganisation enligt NBF till klassisk militär hierarkisk organisation och NBF som utvecklingsmotor försvann i och med ekonomiska neddragningar tillsammans med beslutet om att delta i Europeiska Unionens (EU:s) snabbinsatsstyrka.</p><p>Syftet med denna uppsats är att studera tankar och teorier som ledde fram till NBF och vad som kan vara en förklaring till att NBF försvann några år senare.</p><p>Resultatet av arbetet med uppsatsen tyder på att konceptet NBF i sin abstrakta form blev för teoretiskt. Den processorganisation som infördes med HKV -04 är det tydligaste exemplet på denna abstrakta oklarhet främst vad gäller befäl och därtill kopplat ansvar.  Forskning pekar på att ansvar utgör grunden i militär organisation och verksamhet.  Resultaten visar också på att de positiva lärdomarna från utvecklingen av NBF i form av vikten av ”nätverkande” låg som grund till det mer praktiskt inriktade transformeringen av Försvarsmaktens delar genom Nordic Battle Group, (NBG-08). Resultatet har också påvisat samband mellan NBF utvecklingen och det utökade nordiska samarbetet i form av sjö och luftövervakning samt den likaså utvecklade myndighetssamverkan inom ramen för den nationella krishanteringsförmågan i Sverige.</p>

So- called “Network Based Defense” (NBD) was introduced in Sweden in connection with the transformation of the Swedish Armed Forces in 1999. NBD is based on the U.S. variant Network Centric Warfare (NCW), which in turn is derived from research on the concept of Revolution in Military Affairs (RMA). In Sweden the concept was introduced and included not only the Armed Forces but was intended to also support the Swedish civilian agencies in order to create networks and hence share the available information and thus more effective crisis management and to provide more "bang for the buck." In developing the concept of NBD the Swedish Armed Forces used both economic and human resources, in the form of research, new technologies, new organization and new methods. Between year 2004 and 2006 the Armed Forces once again entered the process of reorganization. This time to “classic” military hierarchical organization and NBD as development engine disappeared due to economic cutbacks, together with the decision to participate in the European Union (EU) rapid reaction force. The purpose of this essay is to study the theories and ideas behind the concept and why the concept "disappeared" a few years later. The result of the work suggests that the concept of NBD in its abstract form was too theoretical. The process of organization introduced by HKV -04 is the clearest example of this abstract ambiguity concerning command and responsibility. Research suggests that responsibility is the basis of military organization and operations. The results also shows that a number of experiences from the development of the NBD has been used in the more practically oriented transformation of the Armed Forces necessary by the commitments for the so- called Nordic Battle Group (NBG-08). The results have also shown correlation between NBD development and the increased Nordic cooperation in the form of sea and air surveillance and the well-developed body interaction within the framework of the national crisis management capacity in Sweden. / Nätverks Baserat Försvar (NBF) infördes i Sverige inom ramen för transformationen av Försvarsmakten från ett invasionsförsvar till ett insatsförsvar. NBF bygger på den amerikanska varianten Network Centric Warfare (NCW) som i sin tur härstammar från forskningen kring begreppet Revolution in Military Affairs (RMA). Konceptet infördes och innefattade inte bara Försvarsmakten utan även stödmyndigheter i syfte att skapa ett nätverk och därmed dela tillgänglig information och därmed effektivisera krishanteringen och ge mer ”pang för pengarna”. Kring utvecklingen av konceptet NBF lades stora resurser i form av forskning, ny teknik, ny organisation och nya metoder. År 2004 till 2006 omorganiserades Försvarsmakten återigen från införd processorganisation enligt NBF till klassisk militär hierarkisk organisation och NBF som utvecklingsmotor försvann i och med ekonomiska neddragningar tillsammans med beslutet om att delta i Europeiska Unionens (EU:s) snabbinsatsstyrka. Syftet med denna uppsats är att studera tankar och teorier som ledde fram till NBF och vad som kan vara en förklaring till att NBF försvann några år senare. Resultatet av arbetet med uppsatsen tyder på att konceptet NBF i sin abstrakta form blev för teoretiskt. Den processorganisation som infördes med HKV -04 är det tydligaste exemplet på denna abstrakta oklarhet främst vad gäller befäl och därtill kopplat ansvar.  Forskning pekar på att ansvar utgör grunden i militär organisation och verksamhet.  Resultaten visar också på att de positiva lärdomarna från utvecklingen av NBF i form av vikten av ”nätverkande” låg som grund till det mer praktiskt inriktade transformeringen av Försvarsmaktens delar genom Nordic Battle Group, (NBG-08). Resultatet har också påvisat samband mellan NBF utvecklingen och det utökade nordiska samarbetet i form av sjö och luftövervakning samt den likaså utvecklade myndighetssamverkan inom ramen för den nationella krishanteringsförmågan i Sverige.