Performance Limits and Geometric Properties of Array Localization

Location-aware networks are of great importance and interest in both civil and military applications. This paper determines the localization accuracy of an agent, which is equipped with an antenna array and localizes itself using wireless measurements with anchor nodes, in a far-field environment. In view of the Cram\'er-Rao bound, we first derive the localization information for static scenarios and demonstrate that such information is a weighed sum of Fisher information matrices from each anchor-antenna measurement pair. Each matrix can be further decomposed into two parts: a distance part with intensity proportional to the squared baseband effective bandwidth of the transmitted signal and a direction part with intensity associated with the normalized anchor-antenna visual angle. Moreover, in dynamic scenarios, we show that the Doppler shift contributes additional direction information, with intensity determined by the agent velocity and the root mean squared time duration of the transmitted signal. In addition, two measures are proposed to evaluate the localization performance of wireless networks with different anchor-agent and array-antenna geometries, and both formulae and simulations are provided for typical anchor deployments and antenna arrays.Comment: to appear in IEEE Transactions on Information Theor

Le cône des représentations d’un ordre d’intervalles

Un ordre d’intervalles est donné sur un ensemble fini d’éléments. Définies de manière appropriée, ses représentations numériques forment un polyèdre convexe. Nos résultats décrivent la structure géométrique de ce polyèdre. Les facettes correspondent à des objets de quatre types : les éléments minimaux, les éléments contractibles ainsi que les nez et les creux de l’ordre d’intervalles (ces deux dernières notions sont inspirées de Doignon et Falmagne [1997]). Le polyèdre n’a qu’un seul sommet, qui est la représentation minimale de l’ordre d’intervalles (au sens de Doignon [1988a] ; plusieurs nouvelles propriétés sont établies ici). Les représentations forment donc un cône convexe. Nous caractérisons les rayons extrêmes de ce cône. L’unicité du sommet est un résultat surprenant, car Balof, Doignon et Fiorini [2012] ont obtenu, pour le polyèdre des représentations d’un semiordre, de nombreux exemples à sommets multiplesA fixed, interval order is considered on a finite set of elements. When appropriately defined, its representations form a convex polyhedron. Our results describe the geometricstructure of the polyhedron. The facets are in a one-to-one correspondence with the objects of oneof four types: the minimal elements, the contractible elements as well as the noses and the hollowsof the interval order (the latter notions are inferred from Doignon and Falmagne [1997]). Thepolyhedron has only one vertex, which is the minimal representation (in the meaning of Doignon[1988a]; new properties are established here). All representations thus form a convex cone. Wecharacterize the extreme rays of this cone. The uniqueness of the vertex came as a surprise tous surprise because Balof, Doignon and Fiorini [2012] obtained, for the polyhedron formed by allrepresentations of a semiorder, numerous examples with multiple vertices

The primate fossil record in the Iberian Peninsula

During the last decade, new discoveries in several Iberian basins, together with the description of previously unpublished finds, have significantly increased the recorded paleodiversity of fossil Primates (Mammalia: Euarchonta) in the Iberian Peninsula. Here we provide an updated compendium of the primate fossil record in Iberia during the Cenozoic and further summarize the changes in primate paleo­diversity through time, which are then analyzed in the light of changing climatic conditions. Thanks to favorable climatic conditions, the highest diversity of Iberian primates was reached during the Eocene, thus reflecting the radiation of both adapoids and omomyoids; only a single plesiadapiform genus is in contrast recorded in the Iberian Peninsula. Near the Eocene-Oligocene boundary, paleoclimatic changes led to a primate diversity crisis and other faunal changes, although two Iberian omomyoids survived the Grande Coupure. From the Middle Miocene onwards, catarrhine primates are recorded in the Iberian Peninsula. During the Middle and Late Miocene, they are represented by pliopithecoids and hominoids, restricted to NE Iberia. The Miocene hominoids from Iberia are of utmost significance for understanding the Eurasian hominoid radiation and its role in the origins of the great-ape-and-human clade. Following the local extinction of these taxa during the early Late Miocene, due to progressively increased seasonality and concomitant changes in plant communities, cercopithecoids are also recorded in the Iberian Peninsula from the latest Miocene through the Plio-Pleistocene, although they finally became locally extinct, whereas hominoids are again represented by fossil humans during the Pleistocene.Durante la última década, nuevos descubrimientos en varias cuencas ibéricas, junto con la descripción de hallazgos previos inéditos, han incrementado significativamente la paleodiversidad de Primates fósiles (Mammalia: Euarchonta) registrada en la Península Ibérica. Proporcionamos aquí un compendio actualizado del registro fósil de los primates en Iberia durante el Cenozoico, y resumimos además los cambios en paleodiversidad de los primates a lo largo del tiempo a la luz de las condiciones climáticas cambiantes. Gracias a condiciones climáticas favorables, la diversidad más alta de primates ibéricos se produjo durante el Eoceno, reflejando así la radiación tanto de los adapoideos como de los omomioideos; en cambio, sólo un único género de plesiadapiformes se registra en la Península Ibérica. Hacia el límite Eoceno-Oligoceno, los cambios paleoclimáticos condujeron a una crisis de diversidad de los primates y otros cambios faunísticos, aunque dos omomioideos ibéricos sobrevivieron a la Grande Coupure. Del Mioceno Medio en adelante, los primates catarrinos se registran en la Península Ibérica. Durante el Mioceno Medio y Superior, están representados por pliopitecoideos y hominoideos, restringidos al NE de Iberia. Los hominoideos del Mioceno de Iberia son de gran importancia para comprender la radiación de los hominoideos eurasiáticos y su papel en los orígenes del clado de los grandes antropomorfos y los humanos. A continuación de la extinción local de estos taxones du­rante el Mioceno Superior inicial, debido al incremento progresivo de la estacionalidad así como a cambios en las comunidades vegetales, los cercopitecoideos también se registran en la Península Ibérica a partir del Mioceno más terminal en adelante. Los cercopitecoideos se registran en la Península Ibérica durante todo el Plio-Pleistoceno, aunque finalmente también se extinguieron localmente, mientras que los hominoideos vuelven a estar representados otra vez por los humanos fósiles durante el Pleistoceno

Analyzing cross-talk between superimposed signals: Vector norm dependent hidden Markov models and applications

We propose and investigate a hidden Markov model (HMM) for the analysis of aggregated, super-imposed two-state signal recordings. A major motivation for this work is that often these recordings cannot be observed individually but only their superposition. Among others, such models are in high demand for the understanding of cross-talk between ion channels, where each single channel might take two different states which cannot be measured separately. As an essential building block we introduce a parametrized vector norm dependent Markov chain model and characterize it in terms of permutation invariance as well as conditional independence. This leads to a hidden Markov chain "sum" process which can be used for analyzing aggregated two-state signal observations within a HMM. Additionally, we show that the model parameters of the vector norm dependent Markov chain are uniquely determined by the parameters of the "sum" process and are therefore identifiable. Finally, we provide algorithms to estimate the parameters and apply our methodology to real-world ion channel data measurements, where we show competitive gating.Comment: An R package can be found at: https://github.com/ljvanegas/VN

Conflicting Objectives in Decisions

This book deals with quantitative approaches in making decisions when conflicting objectives are present. This problem is central to many applications of decision analysis, policy analysis, operational research, etc. in a wide range of fields, for example, business, economics, engineering, psychology, and planning. The book surveys different approaches to the same problem area and each approach is discussed in considerable detail so that the coverage of the book is both broad and deep. The problem of conflicting objectives is of paramount importance, both in planned and market economies, and this book represents a cross-cultural mixture of approaches from many countries to the same class of problem

Computational Complexity of Strong Admissibility for Abstract Dialectical Frameworks

Abstract dialectical frameworks (ADFs) have been introduced as a formalism for modeling and evaluating argumentation allowing general logical satisfaction conditions. Different criteria used to settle the acceptance of arguments arecalled semantics. Semantics of ADFs have so far mainly been defined based on the concept of admissibility. Recently, the notion of strong admissibility has been introduced for ADFs. In the current work we study the computational complexityof the following reasoning tasks under strong admissibility semantics. We address 1. the credulous/skeptical decision problem; 2. the verification problem; 3. the strong justification problem; and 4. the problem of finding a smallest witness of strong justification of a queried argument