Antenna Selection with Power Adaptation in Interference-Constrained Cognitive Radios

The performance of an underlay cognitive radio (CR) system, which can transmit when the primary is on, is curtailed by tight constraints on the interference it can cause to the primary receiver. Transmit antenna selection (AS) improves the performance of underlay CR by exploiting spatial diversity but with less hardware. However, the selected antenna and its transmit power now both depend on the channel gains to the secondary and primary receivers. We develop a novel Chernoffbound based optimal AS and power adaptation (CBBOASPA) policy that minimizes an upper bound on the symbol error probability (SEP) at the secondary receiver, subject to constraints on the average transmit power and the average interference to the primary. The optimal antenna and its power are presented in an insightful closed form in terms of the channel gains. We then analyze the SEP of CBBOASPA. Extensive benchmarking shows that the SEP of CBBOASPA for both MPSK and MQAM is one to two orders of magnitude lower than several ad hoc AS policies and even optimal AS with on-off power control.

Optimal sequential wireless relay placement on a random lattice path

Our work is motivated by impromptu (or ``as-you-go'') deployment of wireless relay nodes along a path, a need that arises in many situations. In this paper, the path is modeled as starting at the origin (where there is the data sink, e.g., the control center), and evolving randomly over a lattice in the positive quadrant. A person walks along the path deploying relay nodes as he goes. At each step, the path can, randomly, either continue in the same direction or take a turn, or come to an end, at which point a data source (e.g., a sensor) has to be placed, that will send packets to the data sink. A decision has to be made at each step whether or not to place a wireless relay node. Assuming that the packet generation rate by the source is very low, and simple link-by-link scheduling, we consider the problem of sequential relay placement so as to minimize the expectation of an end-to-end cost metric (a linear combination of the sum of convex hop costs and the number of relays placed). This impromptu relay placement problem is formulated as a total cost Markov decision process. First, we derive the optimal policy in terms of an optimal placement set and show that this set is characterized by a boundary (with respect to the position of the last placed relay) beyond which it is optimal to place the next relay. Next, based on a simpler one-step-look-ahead characterization of the optimal policy, we propose an algorithm which is proved to converge to the optimal placement set in a finite number of steps and which is faster than value iteration. We show by simulations that the distance threshold based heuristic, usually assumed in the literature, is close to the optimal, provided that the threshold distance is carefully chosen. (C) 2014 Elsevier B.V. All rights reserved.

Interference-Constrained Optimal Power-Adaptive Amplify-and-Forward Relaying and Selection for Underlay Cognitive Radios

In an underlay cognitive radio (CR) system, a secondary user can transmit when the primary is transmitting but is subject to tight constraints on the interference it causes to the primary receiver. Amplify-and-forward (AF) relaying is an effective technique that significantly improves the performance of a CR by providing an alternate path for the secondary transmitter's signal to reach the secondary receiver. We present and analyze a novel optimal relay gain adaptation policy (ORGAP) in which the relay is interference aware and optimally adapts both its gain and transmit power as a function of its local channel gains. ORGAP minimizes the symbol error probability at the secondary receiver subject to constraints on the average relay transmit power and on the average interference caused to the primary. It is different from ad hoc AF relaying policies and serves as a new and fundamental theoretical benchmark for relaying in an underlay CR. We also develop a near-optimal and simpler relay gain adaptation policy that is easy to implement. An extension to a multirelay scenario with selection is also developed. Our extensive numerical results for single and multiple relay systems quantify the power savings achieved over several ad hoc policies for both MPSK and MQAM constellations.

Mixed finite elements for electromagnetic analysis

The occurrence of spurious solutions is a well-known limitation of the standard nodal finite element method when applied to electromagnetic problems. The two commonly used remedies that are used to address this problem are (i) The addition of a penalty term with the penalty factor based on the local dielectric constant, and which reduces to a Helmholtz form on homogeneous domains (regularized formulation); (ii) A formulation based on a vector and a scalar potential. Both these strategies have some shortcomings. The penalty method does not completely get rid of the spurious modes, and both methods are incapable of predicting singular eigenvalues in non-convex domains. Some non-zero spurious eigenvalues are also predicted by these methods on non-convex domains. In this work, we develop mixed finite element formulations which predict the eigenfrequencies (including their multiplicities) accurately, even for nonconvex domains. The main feature of the proposed mixed finite element formulation is that no ad-hoc terms are added to the formulation as in the penalty formulation, and the improvement is achieved purely by an appropriate choice of finite element spaces for the different variables. We show that the formulation works even for inhomogeneous domains where `double noding' is used to enforce the appropriate continuity requirements at an interface. For two-dimensional problems, the shape of the domain can be arbitrary, while for the three-dimensional ones, with our current formulation, only regular domains (which can be nonconvex) can be modeled. Since eigenfrequencies are modeled accurately, these elements also yield accurate results for driven problems. (C) 2014 Elsevier Ltd. All rights reserved.

A model for the classification and survey of clock synchronization protocols in WSNs

Clock synchronization in wireless sensor networks (WSNs) assures that sensor nodes have the same reference clock time. This is necessary not only for various WSN applications but also for many system level protocols for WSNs such as MAC protocols, and protocols for sleep scheduling of sensor nodes. Clock value of a node at a particular instant of time depends on its initial value and the frequency of the crystal oscillator used in the sensor node. The frequency of the crystal oscillator varies from node to node, and may also change over time depending upon many factors like temperature, humidity, etc. As a result, clock values of different sensor nodes diverge from each other and also from the real time clock, and hence, there is a requirement for clock synchronization in WSNs. Consequently, many clock synchronization protocols for WSNs have been proposed in the recent past. These protocols differ from each other considerably, and so, there is a need to understand them using a common platform. Towards this goal, this survey paper categorizes the features of clock synchronization protocols for WSNs into three types, viz, structural features, technical features, and global objective features. Each of these categories has different options to further segregate the features for better understanding. The features of clock synchronization protocols that have been used in this survey include all the features which have been used in existing surveys as well as new features such as how the clock value is propagated, when the clock value is propagated, and when the physical clock is updated, which are required for better understanding of the clock synchronization protocols in WSNs in a systematic way. This paper also gives a brief description of a few basic clock synchronization protocols for WSNs, and shows how these protocols fit into the above classification criteria. In addition, the recent clock synchronization protocols for WSNs, which are based on the above basic clock synchronization protocols, are also given alongside the corresponding basic clock synchronization protocols. Indeed, the proposed model for characterizing the clock synchronization protocols in WSNs can be used not only for analyzing the existing protocols but also for designing new clock synchronization protocols. (C) 2014 Elsevier B.V. All rights reserved.

Direct Link-Aware Optimal Relay Selection and a Low Feedback Variant for Underlay CR

Cooperative relaying combined with selection has been extensively studied in the literature to improve the performance of interference-constrained secondary users in underlay cognitive radio (CR). We present a novel symbol error probability (SEP)-optimal amplify-and-forward relay selection rule for an average interference-constrained underlay CR system. A fundamental principle, which is unique to average interference-constrained underlay CR, that the proposed rule brings out is that the choice of the optimal relay is affected not just by the source-to-relay, relay-to-destination, and relay-to-primary receiver links, which are local to the relay, but also by the direct source-to-destination (SD) link, even though it is not local to any relay. We also propose a simpler, practically amenable variant of the optimal rule called the 1-bit rule, which requires just one bit of feedback about the SD link gain to the relays, and incurs a marginal performance loss relative to the optimal rule. We analyze its SEP and develop an insightful asymptotic SEP analysis. The proposed rules markedly outperform several ad hoc SD link-unaware rules proposed in the literature. They also generalize the interference-unconstrained and SD link-unaware optimal rules considered in the literature.

Emergent Intelligence Based QoS Routing in MANET

Mobile Ad hoc Networks (MANETs) are self-organized, infrastructureless, decentralized wireless networks consist of a group of heterogeneous mobile devices. Due to the inherent characteristics of MANE -Ts, such as frequent change of topology, nodes mobility, resource scarcity, lack of central control, etc., makes QoS routing is the hardest task. QoS routing is the task of routing data packets from source to destination depending upon the QoS resource constraints, such as bandwidth, delay, packet loss rate, cost, etc. In this paper, we proposed a novel scheme of providing QoS routing in MANETs by using Emergent Intelligence (El). The El is a group intelligence, which is derived from the periodical interaction among a group of agents and nodes. We logically divide MANET into clusters by centrally located static agent, and in each cluster a mobile agent is deployed. The mobile agent interacts with the nodes, neighboring mobile agents and static agent for collection of QoS resource information, negotiations, finding secure and reliable nodes and finding an optimal QoS path from source to destination. Simulation and analytical results show that the effectiveness of the scheme. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.ore/licenscs/by-nc-nd/4.0/). Peer-review under responsibility of the Conference Program Chairs

Triplet excited electronic state switching induced by hydrogen bonding: A transient absorption spectroscopy and time-dependent DFT study

The solvent plays a decisive role in the photochemistry and photophysics of aromatic ketones. Xanthone (XT) is one such aromatic ketone and its triplet-triplet (T-T) absorption spectra show intriguing solvatochromic behavior. Also, the reactivity of XT towards H-atom abstraction shows an unprecedented decrease in protic solvents relative to aprotic solvents. Therefore, a comprehensive solvatochromic analysis of the triplet-triplet absorption spectra of XT was carried out in conjunction with time dependent density functional theory using the ad hoc explicit solvent model approach. A detailed solvatochromic analysis of the T-T absorption bands of XT suggests that the hydrogen bonding interactions are different in the corresponding triplet excited states. Furthermore, the contributions of non-specific and hydrogen bonding interactions towards differential solvation of the triplet states in protic solvents were found to be of equal magnitude. The frontier molecular orbital and electron density difference analysis of the T-1 and T-2 states of XT indicates that the charge redistribution in these states leads to intermolecular hydrogen bond strengthening and weakening, respectively, relative to the S-0 state. This is further supported by the vertical excitation energy calculations of the XT-methanol supra-molecular complex. The intermolecular hydrogen bonding potential energy curves obtained for this complex in the S-0, T-1, and T-2 states support the model. In summary, we propose that the different hydrogen bonding mechanisms exhibited by the two lowest triplet excited states of XT result in a decreasing role of the n pi* triplet state, and are thus responsible for its reduced reactivity towards H-atom abstraction in protic solvents. (C) 2016 AIP Publishing LLC.

La participación de la mujer en las Misiones de Paz de Naciones Unidas a través de la actuación de las FF.AA

Resumen: El presente estudio es de Alcance temporal Transversal ygrado de conocimientoDescriptivo. Su tipo de diseño es Cuantitativo, acorde a la lógica de investigación Analítico-Empírica. Recurre a la Investigación Documental e Investigación de Campo. El tipo de muestreo es No Probabilístico, la selección de la muestra es Intencional, y la Unidad de Análisis es El Grado de Integración de las FFAA en cuestiones de Género. El instrumento releva tres Dimensiones: 1. Nivel de integración de género. 2. Posibilidades de desarrollo de carrera y profesional dentro de las Fuerzas Armadas para la mujer. 3. Limitaciones para el desarrollo de la mujer en las Fuerzas Armadas. Se observa en el presente, el nivel de integración de género alcanzado en las misiones de paz de la ONU1, su incidencia en la labor de dichos grupos, y los cambios que ello ha implicado en las Fuerzas Armadas que participan de dichas operaciones internacionales. Asimismo, a fin de considerar el alcance de dicha integración de la mujer en una institución tradicionalmente masculina, se ha considerado pertinente conocer qué dificultades han encontrado para alcanzar la igualdad de trato y oportunidades, a fin de conocer qué aspectos resta mejorar a fin de lograr la participación femenina en las Fuerzas Armadas nacionales y en las misiones de paz, en igualdad de condiciones. Para ello, se ha encuestado la cantidad de 47 hombres y mujeres de las Fuerzas Armadas Argentinas que han participado o que aspiran a participar de las misiones de paz de la Organización de las Naciones Unidas en el mundo, a fin de conocer sus experiencias, apreciaciones y expectativas. El instrumento ha sido diseñado ad hoc para el presente trabajo, para conocer la experiencia de hombres y mujeres de las misiones de paz argentinas en el mundo, respecto del nivel y eficacia de la integración de género. Este tema cumple con los requisitos de estudiar la participación de población local en actividades de relaciones internacionales, dado que se forman en las instituciones locales, y se desempeñan en distintos puntos del globo, como Haití, Líbano o Medio Oriente, representando a la Argentina. Se han obtenido los siguientesResultados: Se ha obtenido una muestra equilibrada en materia de edades. Las mujeres, en un margen del 1 al 10, consideran que la integración de la mujer en las FFAA alcanza una puntuación media (6.96). Los hombres le asignan un puntaje más alto (8.48). En su evaluación de la importancia de la participación de la mujer en las Misiones de Paz, ambos han asignado un puntaje alto (entre 7 y 9) Un 58.3% de las mujeres consideran que la mujer sufre desventajas y limitaciones en la institución, mientras que un 73.9% sostiene, en cambio, que gozan de privilegios, y ningún hombre ha considerado que sufran desventajas y limitaciones. La percepción al respecto es opuesta en ambos géneros. En cuanto a los tratos diferenciados, el 100% de los hombres consideran que existe igualdad en las posibilidades de ascenso; mientras que un 50% aproximadamente sostiene que la exigencia en la Instrucción y Tareas en las Mujeres es equitativa y que éstas reciben un trato menos riguroso que el hombre. Un 73.9% sostiene que existe equidad en la expectativa en las mujeres. Las mujeres tienen, respecto a estos aspectos, percepciones divididas, lo que permite apreciar diversidad en las experiencias vividas por éstas y heterogeneidad en el trato recibido: mientras que porcentajes entre 50 y 80% consideran igualdad en los tratos recibidos; porcentajes cercanos al 25 y 30% consideran que tienen menores posibilidades de ascenso, menor exigencia en tareas y evaluación y menor trato riguroso. Porcentajes de entre 12 y 30%, en cambio, consideran que la exigencia y el trato son superiores para la mujer. Para ambos géneros, la incorporación de las mujeres a las FFAA ha sido positiva, aunque algunos hombres (26.1%) la consideran negativa. Asimismo, mientras que un 73.9% de hombres calificarían el desempeño de la mujer como igual al del hombre; el 75% de las mujeres lo consideran diferente y complementario. En cuanto a las ventajas en al conformación de equipos mixtos en las misiones de paz, las mujeres han mostrado una visión estereotipada de sí mismas, valorando tareas de asistencia y cuidado, mientras el los hombres han valorado su participación para el éxito de la misión, para mejorar relaciones con la población local y otras variadas. Los hombres han reconocido la existencia de limitaciones para el desarrollo de la mujer en su carrera militar, como el machismo, la discriminación y las restricciones para el ascenso, mientras que las mujeres se centran en la maternidad y el rechazo al liderazgo femenino como principales problemas.Se concluye en el presente que: La participación de la mujer en las Fuerzas Armadas y en las misiones de paz de Argentina son alarmantemente insuficientes. Sus niveles de participación son mínimos. La necesidad de la integración de género es creciente, dado que se su presencia en las misiones de paz resulta fundamental para establecer vínculos con las poblaciones locales, empoderar a sus mujeres y atender a las necesidades de personas vulneradas bajo todo tipo de violencia. Las Fuerzas Armadas se pueden beneficiar de la integración de género, ya que se trata de una institución eminentemente heterogénea. Las misiones de paz resultan un espacio ideal para incorporar la perspectiva de género y encontrar soluciones creativas a los conflictos que la institución debe enfrentar en todos los ámbitos

Calidad de vida en adultos con diagnóstico de psoriasis de la ciudad de Paraná : diferencias según sexo

Resumen: La presente investigación tuvo como objetivo evaluar la percepción de la calidad de vida en aquellos adultos con diagnóstico de psoriasis de la ciudad de Paraná y conocer diferencias según sexo. El diseño de investigación fue de tipo descriptivo – correlacional, transversal y de campo; el muestreo fue intencional no probabilístico. Con una muestra compuesta por 36 sujetos de ambos sexo, de 18 a 65 años. Los instrumentos que se aplicaron fueron el World Health Organization Quality of Life Questionaire (WHOQOL-100), en su versión Argentina (Bonicatto y Soria, 1998), junto con dos cuestionarios ad hoc, uno sociodemográfico y otro para explorar la imagen corporal. El procesamiento de la información obtenida a través del WHOQOL-100 se realizó mediante el programa Stadistical Package for the Social Sciences (SPSS) 21. Mientras que los ítems del cuestionario ad hoc de imagen corporal fueron evaluados cualitativamente de manera individual, las respuestas fueron agrupadas por categorías y luego se obtuvieron las frecuencias, porcentajes y análisis de contenido. Se observó que los adultos con diagnóstico de psoriasis de la ciudad de Paraná presentaron en general, una buena calidad de vida. Se determinó que existen diferencias según sexo, las mujeres obtuvieron mayores puntajes en los dominios Relaciones Sociales y Espiritualidad, como también en las facetas de sentimientos positivos, relaciones personales, seguridad física y espiritualidad. Por último, se observó que la imagen corporal se vio afectada por dicha enfermedad en la muestra estudiada

Del combate singular al singular combate sexual en la sátira trovadoresca medieval gallego-portuguesa

Integran este número de la revista ponencias presentadas en Studia Hispanica Medievalia VIII: Actas de las IX Jornadas Internacionales de Literatura Española Medieval, 2008, y de Homenaje al Quinto Centenario de Amadis de Gaula.

PPs without Disguises: Reply to Bruening

[EN]Bresnan and Nikitina (2009) and Rappaport Hovav and Levin (2008) show that, contrary to standard assumptions, fixed-theme idioms may appear in to-constructions under certain pragmatic circumstances. Bruening (2010a) contends that the cases they present are in fact R(ightward)-dative shifts, double object constructions with the object projected to the right. In this article, we argue that Bruening’s proposed theoretical apparatus is unnecessarily complex and ad hoc and falls short of explaining the main facts it is supposed to deal with, massively overgenerating. A regular PP structure is argued to be empirically more adequate and conceptually simpler, avoiding the main problems of the R-dative shift analysis. New empirical evidence concerning pairlist readings and scope freezing also suggests that the empirical facts about idioms should be reconsidered in completely different terms.

Pautas de conducta constructiva en psicomotricidad a los dos años

[Es]Este trabajo forma parte de una investigación empírica que aplica la metodología observacional a la incipiente actividad constructiva propia de la psicomotricidad espontánea a los dos años de edad. Es un estudio idiográfico, el diseño observacional utilizado es nomotético, de seguimiento y multidimensional. El instrumento de observación desarrollado ad hoc para el registro de la conducta conscontructiva es el formato de campo “la construcción en psicomotricidad durante el tercer año de vida”. La fiabilidad del instrumento se establece a partir del grado de concordancia entre los observadores. Los resultados, obtenidos mediante el análisis de coocurrencias, informan sobre las condiciones, modalidades, tendencias, evolución y niveles de acción que estas primeras conductas constructivas despliegan. Esta actividad de construcción, de acuerdo con la teoría psicogenética walloniana, puede ser considerada invención de nuevas conductas adecuadas a las nuevas situaciones. Su suspensión da lugar a símbolos enactivos, precursores del juego simbólico infantil.

International Workshop for Management and Trade of Caiman yacare, Gainsville, FL, 3-5 October 2002

A workshop was held 3-5 October 2002 in Gainesville, Florida, USA to discuss management, conservation and trade in Caiman yacare. Twenty five official participants represented the four yacare range states (Argentina, Bolivia, Brazil, Paraguay), Venezuela, USA, the meeting sponsors (US Fish and Wildlife Service, CITES Secretariat, Louisiana Fur and Alligator Council), TRAFFIC Sur America and Crocodile Specialist Group. A series of country reports detailing yacare management in the four range states were distributed in Spanish and English prior to the meeting and presentations on these and on general principles of crocodilian harvest, conservation and management provided the basis for the discussions. Three working groups considered: • Requirements and field techniques for field data collection. • Requirements and techniques for regulation of harvest. • Requirements and processes for regulation of trade and export. Written reports of working groups and a plenary drafting session were finalized during the meeting and distributed, with the country reports, to participants. The workshop drafted a framework for caiman management and regulation that could be used as a template and adapted for use in each range state. The meeting agreed to convene an ad-hoc working group of range state representatives to continue discussions on the harmonization of caiman management into the future.