Automatic modulation recognition is an important part of communications electronic monitoring and surveillance systems where it is used for signal sorting and receiver switching. ' This thesis introduces a novel application of multivariate statistical techniques to the problem of automatic modulation classification. The classification technique uses modulation features derived from time-domain parameters of instantaneous signal envelope, frequency and phase. Principal component analysis (PCA) is employed for data reduction and multivariate analysis of variance (MANOVA) is used to investigate the data and to construct a discriminant function to enable the classification of modulation type. MANOVA is shown to offer advantages over the techniques already used for modulation recognition, even when simple features are used. The technique is used to construct a universal discriminator which is independent of the unknown signal to noise ratio (SNR) of the received signal. The universal discriminator is shown to extend the range of signal-to-noise ratios (SNRs) over which discrimination is possible, being effective over an SNR range of 0-4OdB. Development of discriminant functions using MANOVA is shown to be an extensible technique, capable of application to more complex problems. i

The work is dedicated to problems of communication in a selected organization. The author decided to limit the work on the information transmission within one section in the Ministry of Education, Youth and Sports. The reason for selecting the organization is the importance of educational issues and the special position of the section within the ministry. The main objective of this work is to describe and subsequent analysis of communication within the Ministry of Education, Youth and Sports, both in the selected section as well as the relationship between that section and other departments at the ministry, or between the Section and external entities . The work is divided into three parts: theoretical, practical and proposal. Part of the thesis is own research and proposals for measures which may lead to better results (higher awareness) in communication.

This dissertation focuses on how transportation and information networks change the geographic distribution of economic activity. The first and second chapters examine the geographic distribution of patenting in the nineteenth century United States. The third explores the impact of the rollout of Rural Free Delivery (RFD) in the early twentieth century on voting behavior. In Chapter One, I examine the relationship between patenting activity and transportation access, using a newly collected panel dataset at the county level spanning the nineteenth century United State. I find a robust, statistically significant, positive effect of increases in local transportation access on patents per capita. The effect is large --- patents per capita double over the twenty years following introduction of the railroad. I ask if this increase is due to inventors responding to larger markets afforded by transportation improvements. I find modest evidence that market access explains the increase in patent activity, but most of the relationship seems to be explained by other variables correlated with transportation access. The second chapter proposes a novel way to study technology diffusion, investigating how transportation changes information absorption. Using digitized patent texts, I measure whether any given patent mentions previous, novel technologies within a particular window of time. The arrival speed of these new ideas is only weakly related transportation improvements; expansions of the transportation network disproportionately benefit the most develop places. Together, these two chapters suggest that the positive effect of transportation access on patenting is due to transportation forming a nexus that encourages local agglomerations, but leave the question of the overall impact of lager transportation networks on innovation unclear. Chapter Three focuses on the how mail delivery spread new information, studying the rollout of Rural Free Delivery (RFD) in the early twentieth century. Using a newly constructed panel data set, the analysis shows that voters in communities receiving more RFD routes distributed their votes to more parties; however, there is no evidence of an effect on turnout. RFD shifted positions taken by Representatives in line with their rural constituents, including increased support for pro-temperance and anti-immigration policies. The results only occur in counties with local newspapers, suggesting that the main channel is a lowered cost to voters of acquiring information relevant to political choices.

An Information Theoretic approach is used for studying the effect of noise on various spiking neural systems. Detailed statistical analyses of neural behaviour under the influence of stochasticity are carried out and their results related to other work and also biological neural networks. The neurocomputational capabilities of the neural systems under study are put on an absolute scale. This approach was also used in order to develop an optimisation framework. A proof-of-concept algorithm is designed, based on information theory and the coding fraction, which optimises noise through maximising information throughput. The algorithm is applied with success to a single neuron and then generalised to an entire neural population with various structural characteristics (feedforward, lateral, recurrent connections). It is shown that there are certain positive and persistent phenomena due to noise in spiking neural networks and that these phenomena can be observed even under simplified conditions and therefore exploited. The transition is made from detailed and computationally expensive tools to efficient approximations. These phenomena are shown to be persistent and exploitable under a variety of circumstances. The results of this work provide evidence that noise can be optimised online in both single neurons and neural populations of varying structures.

The first chapter considers a common agency model where two competition authorities share information about a firm under investigation. It shows that information-sharing can sometimes be welfare detrimental unless the authorities coordinate their enforcement policies as well as share information. The reason behind is that the authorities may have different leniency levels and the firm may decide to provide less precise information to one in an attempt to appeal the other. Furthermore it shows that the authorities may want to distort their policies in order to prevent the firm from obscuring the information it provides. The second chapter studies the seller's incentives to provide misleading advice about complex goods such as consumer electronics, banking or phone services. It shows how the incentives to give biased and imprecise advice are affected by the possibility of ex-post litigation, when a court or consumer protection authority investigates how biased the advice is and penalises accordingly. It finds that a more biased advice will also be less precise, thus, a stricter punishment for deceiving consumers also increases precision. The third chapter analyses the impact of trade credit on a relational contract between two vertically related firms. The firms operate in an environment with unobservable shocks, like a developing country or a black market, which create moral hazard in the repayment decision. It shows that the quantity sold in the market will be distorted downwards in order to curb the constrained firm's incentives to steal the credit and derives the optimal repayment scheme.

Cette thèse étudie de manière théorique les déterminants et les conséquences économiques de la transmission d'information entre agents rationnels.Un agent possède une information privée sur un état du monde, émet un message qui est observé par un agent a priori non informé, et ce dernier décide d'une action à prendre. L'information éventuellement transmise est sans engagement, sans coût et sans possibilité de vérification.L'état du monde et l'action impactent l'utilité des deux agents.Il y a possibilité de transmission d'information dans la situation d'équilibre où l'association d'un message à un ensemble d'états du monde induit l'action qui la détermine.La nature des équilibres est en général conditionnée par le conflit d'intérêt des agents, qui est la distance entre leur action préférée, étant donné l'état du monde.Dans les trois chapitres de la thèse, nous considérons un état du monde et une action bi-dimensionnels, une révélation d'information utilisant deux messages à l'équilibre, et nous supposons que l'utilité de l'agent non informé décroît avec la distance euclidienne entre l'état du monde, qu'il ne connait pas a priori, et son action.Le conflit d'intérêt des agents est alors la distance entre l'état du monde et l'action préférée de l'agent informé, qu'il ne décide pas.Chaque chapitre étudie l'impact de différents facteurs conflictuels sur les conditions d'existence d'équilibres informatifs.Dans le premier chapitre, nous étudions l'impact de la prise en compte, par l'agent informé, d'une complémentarité des deux dimensions de l'état du monde. Dans le second chapitre, nous étudions l'impact d'un biais constant de l'agent informé relativement à l'action préférée de l'agent non informé. Enfin, dans le troisième chapitre, nous étudions l'impact d'un intérêt croissant pour associer une action plus grande à un état du monde plus grand. / We investigate how information is transmitted and processed between rational agents, from a theoretical perspective.An informed agent holds private information on a state of the world, sends a message which is observed by an uninformed agent, who takes a decision.Information transmitted is without commitment, at no cost and unverifiable.State and action impact both agents' utility.There is information transmission in equilibrium when the relationship between messages and states induces the action that precisely generates the relationship.In the three chapters, we consider a two-dimensional state, a two-dimensional action, an information revelation that uses two messages in equilibrium, and we assume that the uninformed agent's utility function is decreases with the euclidean distance between state and action.Then agents' conflict of interest simplifies to the distance between state and the most highly preferred informed agent's action.In each chapter, we investigate how specific conflicting features of the agents' utility functions impact the equilibrium existence conditions.In chapter 1, we investigate the impact of complementarities between the dimensions in the informed agent's utility. In chapter 2, we investigate the impact of a constant bias of the informed agent with regard to the uninformed agent's preferred action. In chapter 3, we investigate the informed agent's incentives to exaggerate more with an higher state.

No description available.

Les oscil·lacions d'activitat neuronal són un fenomen omnipresent a l'escorça cerebral. La funció d'aquestes oscil·lacions, però, no està clara. ¿Són només un epifenomen de les elevades taxes de descàrrega de potencials d'acció, o representen un procés fonamental? Per tal d'aclarir aquesta qüestió, en aquest treball hem aplicat models computacionals basats en xarxes neurobiològicament plausibles per tal d'investigar alguns dels resultats experimentals recents més rellevants. Primerament, estudiem la rellevància de les oscil·lacions en processos d'atenció i després en un context més general de teoria d'informació. Els resultats donen suport a la idea que les oscil·lacions representen un mecanisme independent. Demostrem que l'atenció modula les oscil·lacions gamma de manera independent de la taxa de descàrrega de potencials d'acció. També es mostra que la transmissió d'informació entre àrees corticals depèn tant de la fase com de la potència espectral de les oscil·lacions. A més, la velocitat amb què es produeix aquesta transmissió d'informació augmenta en funció de la potència espectral en bandes de freqüències específiques. Aquests resultats suggereixen que les oscil·lacions representen un mecanisme biològicament plausible per mitjançar les interaccions entre àrees cerebrals i, per tant, per establir un vincle entre activitat neuronal i comportament. / Oscillatory neuronal activity is an omnipresent phenomenon in the cerebral cortex. However, the actual function of these oscillations remains unclear. Are they just an epiphenomenon of elevated firing rates or do they represent a fundamental process on their own? Based on experimental work, we apply computational modeling to address this question. We first study the role of oscillations in attentional processes and then in a more general, information theoretical context. Our results support the idea that oscillations represent an independent mechanism. In particular, we show that attention modulates gamma oscillations independently of rates and that the flow of information between brain areas depends both on the phase and on the spectral power of oscillations. Moreover, we show that the speed of information exchange increases as a function of spectral power in specific frequency bands. Taken together, these results suggest that oscillations are a mechanism employed by the brain to control actual interactions between brain areas and thus likely have a link to behavior.

Les agences de notations ont récemment été l'objet d'une grande attention. Leur responsabilité dans la crise des subprimes a été questionné. Les médias ont mis en avant les notes trop généreuses qui avaient été attribué à certains produits complexes, avant de s'interroger sur leur comportement quand elles ont dégradé les notes des dettes souveraines. Dans cette thèse, après avoir revu une partie de la littérature sur le sujet, je m'interroge sur deux aspects spécifique de leur activité:(i) Quels sont les conséquences de confier une information publique (comme une note de crédit) à une entité privée ?(ii) Les agences de notations disent avoir pour principal actif la réputation. Cette dernière peut expliquer pourquoi on observe des périodes de sur- notations et d'autres de sous-notations ? / Credit rating agencies have recently been under a lot of scrutiny. Their responsibility in the last financial crisis has been questioned. They received much attention from the media. The credit rating agencies have been blamed for their too generous ratings before the crisis and also for being too severe during the European debt crisis. In this thesis, after an overlook of the recent literature, I look at two specific issues related to their activity: • What issues arise when public information is released by a private entity on financial markets? • Can reputation explains why a credit rating agency can be caught underrating (respectively overrating)

American Depository Receipts (ADRs) represent shares of foreign firms that are issued and traded in the U.S. Since an ADR and its underlying shares represent ownership interest of the same firm, they should be perfect substitutes in a perfect market. However, market imperfections such as differences in information environment, liquidity, investment and trading restrictions, taxes, control right, corporate governance might make them less-than-perfect substitutes. These imperfections, on the other hand, also present opportunities for research. This dissertation consists of two essays on ADRs, both related to the effects of less-thanperfect information. Specifically, the first essay examines the return and volatility transfers between ADRs and their underlying home shares. Our investigation differs from the previous studies in that we cover substantially more countries and that we attempt to explain the variations in the extents of transfer effects both across firms and across countries. Various hypotheses are developed, based on the premise that barriers associated with trading, investments, and corporate governance would lower the extent or effectiveness of transfers. Overall, our empirical results support these hypotheses. The second essay takes the viewpoint of the issuing firms. Supposedly, an issuer's timing and dollar amount raised depend on the conditions of three markets: its home equity market, the U.S. equity market, and the currency market. From purely the standpoint of information accessibility, ADR issuers are likely to time their issues or set their amounts with respect to the conditions of the home equity market and/or currency market, with which they are more familiar. On the other hand, issuers typically employ the assistance of U.S. investment banks, and therefore they may be well-informed about the U.S. equity market. This is largely an empirical issue. Generally, our empirical results are mixed, but there is somewhat stronger evidence for the U.S. equity market being more important when setting the issue amount. There is also evidence that suggests regulations having influences on such activities.