2,061 research outputs found

    Distributed Linear Precoding and User Selection in Coordinated Multicell Systems

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    In this manuscript we tackle the problem of semi-distributed user selection with distributed linear precoding for sum rate maximization in multiuser multicell systems. A set of adjacent base stations (BS) form a cluster in order to perform coordinated transmission to cell-edge users, and coordination is carried out through a central processing unit (CU). However, the message exchange between BSs and the CU is limited to scheduling control signaling and no user data or channel state information (CSI) exchange is allowed. In the considered multicell coordinated approach, each BS has its own set of cell-edge users and transmits only to one intended user while interference to non-intended users at other BSs is suppressed by signal steering (precoding). We use two distributed linear precoding schemes, Distributed Zero Forcing (DZF) and Distributed Virtual Signal-to-Interference-plus-Noise Ratio (DVSINR). Considering multiple users per cell and the backhaul limitations, the BSs rely on local CSI to solve the user selection problem. First we investigate how the signal-to-noise-ratio (SNR) regime and the number of antennas at the BSs affect the effective channel gain (the magnitude of the channels after precoding) and its relationship with multiuser diversity. Considering that user selection must be based on the type of implemented precoding, we develop metrics of compatibility (estimations of the effective channel gains) that can be computed from local CSI at each BS and reported to the CU for scheduling decisions. Based on such metrics, we design user selection algorithms that can find a set of users that potentially maximizes the sum rate. Numerical results show the effectiveness of the proposed metrics and algorithms for different configurations of users and antennas at the base stations.Comment: 12 pages, 6 figure

    Reliable fault-tolerant model predictive control of drinking water transport networks

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    This paper proposes a reliable fault-tolerant model predictive control applied to drinking water transport networks. After a fault has occurred, the predictive controller should be redesigned to cope with the fault effect. Before starting to apply the fault-tolerant control strategy, it should be evaluated whether the predictive controller will be able to continue operating after the fault appearance. This is done by means of a structural analysis to determine loss of controllability after the fault complemented with feasibility analysis of the optimization problem related to the predictive controller design, so as to consider the fault effect in actuator constraints. Moreover, by evaluating the admissibility of the different actuator-fault configurations, critical actuators regarding fault tolerance can be identified considering structural, feasibility, performance and reliability analyses. On the other hand, the proposed approach allows a degradation analysis of the system to be performed. As a result of these analyses, the predictive controller design can be modified by adapting constraints such that the best achievable performance with some pre-established level of reliability will be achieved. The proposed approach is tested on the Barcelona drinking water transport network.Postprint (author's final draft

    Low-complexity user selection for rate maximization in MIMO broadcast channels with downlink beamforming

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    We present in this work a low-complexity algorithm to solve the sum rate maximization problem in multiuser MIMO broadcast channels with downlink beamforming. Our approach decouples the user selection problem from the resource allocation problem and its main goal is to create a set of quasiorthogonal users. The proposed algorithm exploits physical metrics of the wireless channels that can be easily computed in such a way that a null space projection power can be approximated efficiently. Based on the derived metrics we present a mathematical model that describes the dynamics of the user selection process which renders the user selection problem into an integer linear program. Numerical results show that our approach is highly efficient to form groups of quasiorthogonal users when compared to previously proposed algorithms in the literature. Our user selection algorithm achieves a large portion of the optimum user selection sum rate (90%) for a moderate number of active users

    Uburyo : Delivering of a Sustainable System of Loans for Education : Volume I y II

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    Integrating a Grants Manager and an Employment Bureau Uburyo, a sustainable mini-loans system, will help academic institutions from developing countries to administrate subventions in order to grow economically and get more and more students

    Citrus psorosis virus movement protein contains an aspartic protease required for autocleavage and the formation of tubule-like structures at plasmodesmata

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    Plant virus cell-to-cell movement is an essential step in viral infections. This process is facilitated by specific virus-encoded movement proteins (MPs), which manipulate the cell wall channels between neighboring cells known as plasmodesmata (PD). Citrus psorosis virus (CPsV) infection in sweet orange involves the formation of tubule-like structures within PD, suggesting that CPsV belongs to "tubuleforming" viruses that encode MPs able to assemble a hollow tubule extending between cells to allow virus movement. Consistent with this hypothesis, we show that the MP of CPsV (MPCPsV) indeed forms tubule-like structures at PD upon transient expression in Nicotiana benthamiana leaves. Tubule formation by MPCPsV depends on its cleavage capacity, mediated by a specific aspartic protease motif present in its primary sequence. A single amino acid mutation in this motif abolishes MPCPsV cleavage, alters the subcellular localization of the protein, and negatively affects its activity in facilitating virus movement. The amino-terminal 34-kDa cleavage product (34KCPsV), but not the 20-kDa fragment (20KCPsV), supports virus movement. Moreover, similar to tubule-forming MPs of other viruses, MPCPsV (and also the 34KCPsV cleavage product) can homooligomerize, interact with PD-located protein 1 (PDLP1), and assemble tubule-like structures at PD by a mechanism dependent on the secretory pathway. 20KCPsV retains the protease activity and is able to cleave a cleavage-deficient MPCPsV in trans. Altogether, these results demonstrate that CPsV movement depends on the autolytic cleavage of MPCPsV by an aspartic protease activity, which removes the 20KCPsV protease and thereby releases the 34KCPsV protein for PDLP1-dependent tubule formation at PD. IMPORTANCE Infection by citrus psorosis virus (CPsV) involves a self-cleaving aspartic protease activity within the viral movement protein (MP), which results in the production of two peptides, termed 34KCPsV and 20KCPsV, that carry the MP and viral protease activities, respectively. The underlying protease motif within the MP is also found in the MPs of other members of the Aspiviridae family, suggesting that protease-mediated protein processing represents a conserved mechanism of protein expression in this virus family. The results also demonstrate that CPsV and potentially other ophioviruses move by a tubule-guided mechanism. Although several viruses from different genera were shown to use this mechanism for cell-to-cell movement, our results also demonstrate that this mechanism is controlled by posttranslational protein cleavage. Moreover, given that tubule formation and virus movement could be inhibited by a mutation in the protease motif, targeting the protease activity for inactivation could represent an important approach for ophiovirus control.Fil: Robles Luna, Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Peña, Eduardo José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Borniego, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Heinlein, Manfred. Université de Strasbourg; Francia. Centre National de la Recherche Scientifique; FranciaFil: Garcia, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; Argentin

    Power and modulation assignment via Perron-root optimization for interference limited systems

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    The maximization of the total sum rate depends on the proper power and modulation assignment. The feasibility of such resource assignment is susceptible to the set of links that are attempted to be scheduled. In this paper we address the problem of maximizing the sum rate while guaranteeing resource assignment feasibility in interference limited wireless systems. Unlike the current literature, the allowed signal-to-interference-plus-noise ratio is constrained to take values from a finite set associated with a finite number of available modulations. Therefore, we present suboptimal but efficient algorithms to solve the joint user selection and resource (power and modulation) assignment, which is a combinatorial problem. The feasibility of the resource assignment is verified by a criterion based on the Perron-Frobenius theory whilst the optimization of the resource allocation is achieved either by user-removal like techniques or by a novel criterion derived from the Perron-Frobenius theory. We provide numerical results to confirm the efficiency of our resource allocation algorithms compared to the optimal resource allocation

    Anthropometric measures as predictive indicators of metabolic risk in a population of “holy week costaleros”

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    Preventive measures are a priority in those groups that perform intense physical efforts without physical preparation and that can also be overweight or obese. One of the groups that reflect these characteristics is the costaleros of the Holy Week of Andalusia, Spain. This paper aims to describe the effect of obesity on blood pressure. A descriptive cross-sectional study was conducted on 101 costaleros. The anthropometric measures were determined through segmental impedance. Cardiac recovery and anaerobic power were measured through the Ruffier–Dickson test and the Abalakov test, respectively. Blood pressure was measured when the individuals were at rest. The Kruskal–Wallis test was applied for of continuous parameters and the X2 test for dichotomous measures. Binary logistic regression models were used for the subsequent analysis with R-square and Receiver Operating Characteristic (ROC) curves. The average population was 28 years of age, 173.7 cm tall, and 82.59 Kg weigh. The excess of body fat was 11.27 Kg and Body Mass Index was 27.33 Kg/m2. 72.3% showed abnormal blood pressure and 68.2% were overweight. 32.7% had a waist-hip ratio higher than 0.94. The probability of presenting abnormal blood pressure was higher among the subjects whose fat content was higher and muscle content was lower

    Gym of ecological lumen of Valdespino Somoza

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    El concepto de ecología y de utilización de materiales reciclables puede parecer que está de moda más que nunca en los tiempos actuales. Acostumbrados a la aplicación de las últimas tecnologías en los aparatos más avanzados al servicio del deporte, el rendimiento y a su vez al cuidado de la salud en sofisticados centros deportivos, encontramos en el ámbito rural, ubicado en plena maragatería, Valdespino de Somoza, una iniciativa cargada de sentido del cuidado con el entorno y de reutilización de materiales usados no sólo con un fin educativo y estético sino con un sentido totalmente práctico como fruto de una iniciativa que busca el homenaje de una especie en vías de extinción: el negrillo. Ésta realidad es fruto de varios años de trabajo y perfeccionamiento de un profesor de Educación FísicaThe concept of ecology and use of recyclable materials may appear to be more fashionable than ever in modern times. Accustomed to the application of the latest technologies in the most advanced sportsequipment service, performance and in turn to health care in sophisticated sports centers, found in rural areas, in heart maragatería, Valdespino Somoza, an initiative laden sense of care with the environmentand recycling used not only an educational and aesthetic purpose but with a totally practical sense as a result of an initiative to the homage of a species endangered materials: the Field Elm. This reality is the result of several years of work and development of a passionate teacher of Physical Educatio

    Transmisión y Monitorización Remota de Señales Respiratorias en Niños mediante SIP y tecnologías Web 2.0

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    Este artículo presenta el Sistema diseñado para permitir la monitorización remota de niños con problemas de apnea. El Sistema se ha diseñado en colaboración con el Hospital de LA PAZ, para identificar los elementos clave para detectar la apnea, incluyendo las señales que deben ser analizadas y las funcionalidades claves del sistema. En LA PAZ también se realizarán las pruebas reales de sistema final. El sistema desarrollado pretende mejorar la calidad de vida de los pacientes monitorizados por un lado y por otro mejorar el conocimiento sobre la apnea en pacientes reales mediante la recogida de gran cantidad de señales. La información se recoge y analiza en tiempo real para permitir una detección temprana de apneas. La información recogida por los sensores también se almacena en una Base de Datos central que permitirá un posterior análisis más profundo de las señales recogidas. El Sistema permite una visualización remota utilizando navegadores Web estándar, integrando tecnologías Web 2.
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