A Superstabilizing log⁡(n)\log(n)-Approximation Algorithm for Dynamic Steiner Trees

In this paper we design and prove correct a fully dynamic distributed algorithm for maintaining an approximate Steiner tree that connects via a minimum-weight spanning tree a subset of nodes of a network (referred as Steiner members or Steiner group) . Steiner trees are good candidates to efficiently implement communication primitives such as publish/subscribe or multicast, essential building blocks for the new emergent networks (e.g. P2P, sensor or adhoc networks). The cost of the solution returned by our algorithm is at most $\log |S|$ times the cost of an optimal solution, where $S$ is the group of members. Our algorithm improves over existing solutions in several ways. First, it tolerates the dynamism of both the group members and the network. Next, our algorithm is self-stabilizing, that is, it copes with nodes memory corruption. Last but not least, our algorithm is \emph{superstabilizing}. That is, while converging to a correct configuration (i.e., a Steiner tree) after a modification of the network, it keeps offering the Steiner tree service during the stabilization time to all members that have not been affected by this modification

Materiales compuestos de cáscaras de maní y cemento. Influencia de diferentes tratamientos químicos sobre las propiedades mecánicas

An abundance of agri-food waste in the area around Cordoba, Argentina, has driven the development of new construction materials. This study explored the applicability of peanut shells as additions in cement blends and the suitability of the properties of the resulting mixes for use in construction materials. The mechanical properties of the specimens were observed to improve when the shells were previously treated with quicklime (CaO) or when sodium silicate and aluminium sulphate were added to the blend. While the resulting materials did not exhibit the same mechanical properties as traditional mortars and concretes, they do appear to be apt for use in lightweight and non-bearing structures.La abundante disponibilidad de residuos de la agroindustria local (Córdoba, Argentina), ha promovido el desarrollo de nuevos materiales para la construcción. Este trabajo de investigación se desarrolla a partir de la utilización de cáscara de maní como agregado en mezclas de cemento a fin de conocer las propiedades obtenidas en relación al tratamiento de dicho agregado, para la producción de materiales de construcción. Los ensayos demostraron mejoras en las propiedades mecánicas de las probetas realizadas con cemento y cáscaras previamente tratadas con cal viva (CaO), también en aquéllas aditivadas con silicato de sodio y sulfato de aluminio. Si bien los materiales resultantes no tienen las propiedades mecánicas de los morteros y hormigones tradicionales, parecen interesantes para ser aplicadas en componentes de construcción livianos y de uso no portante

Persistent itching associated to silodosin in an elderly patient: Implications for drug-drug interactions and pharmacogenetics

Itching is a complaint affecting especially the elderly, in whom comorbidities and polypharmacy increase the risk of adverse drug reactions. We reported the case of an 83-year-old man with a generalized itching lasting more than 3 years underwent to our attention during his enrollment in a clinical study at University Hospital of Salerno, Italy where he was planned for a thromboendoarteriectomy because of left internal carotid artery stenosis. His medical history included arterial hypertension, ischemic heart disease, chronic cerebrovasculopathy, dyslipidaemia and prostatic hyperplasia. His therapy was olmesartan medoxomil 10 mg/die, nebivolol 5 mg x 1/2/die, acetylsalicylic acid 100 mg/die, omeprazole 20 mg/die, atorvastatin 20 mg/die, supplements contain ing EPA and DHA, vitamins K2, B6, B12 and folic acid (vit B9) and silodosin 8 mg/die. The patient’s demographic clinic, laboratory data and a pharmacological anamnesis were collected. Screening of two ABCB1 polymorphisms associated to a decrease of P-glycoprotein (P-gp) activity was performed by realtime PCR. An iatrogenic cause of the itching was suspected and the Naranjo algorithm was applied, revealing possible association between such an adverse reaction and all used drugs. Because the patient reported the beginning of the itching in concomitance with the aspirin assumption, this agent was discontinued but without improvement. Then, because silodosin-atorvastatin interaction may increase the silodosin plasma concentration, this drug was switched to doxazosin and the itching disappeared. This clinical case stresses the potential misleading based on the patients’ beliefs and the importance to consider all the patients’ available information to ascertain the cause of adverse drug reactions

An Efficient Distributed Algorithm for Generating and Updating Multicast Trees

As group applications are becoming widespread, efficient network utilization becomes a growing concern. Multicast transmission represents a necessary lower network service for the wide diffusion of new multimedia network applications. Multicast transmission may use network resources more efficiently than multiple point-to-point messages; however, creating optimal multicast trees (Steiner Tree Problem in networks) is prohibitively expensive. This paper proposes a distributed algorithm for the heuristic solution of the Steiner Tree Problem, allowing the construction of effective distribution trees using a coordination protocol among the network nodes. Furthermore, we propose a novel distributed technique for dynamically updating the multicast tree. The approach proposed has been implemented and extensively tested both in simulation, and on experimental networks. Performance evaluation indicates that the distributed algorithm performs as well as the centralized version, providing good levels of convergence time and communication complexity

MEMS Magnetometer Using Magnetic Flux Concentrators and Permanent Magnets

A novel frequency modulated MEMS magnetometer is presented. The new device is inspired by the magnetic force microscopy technique, it combines standard MEMS technology with magnetic elements to obtain a magnetometer with potential for low power consumption and high performance. The analytical model and the characterization of the first proof-concept device are presented

Diseño de eco luminarias para espacios exteriores : reutilización de antenas de TV satelital y energía fotovoltáica

Ponencia en VIII Jornadas de Investigación y II Jornadas de Investigación de Becarios y Doctorandos Encuentro y Reflexión : investigación + transferencia + desarrolloLa Convención Marco de Naciones Unidas sobre el Cambio Climático (CMNUCC, 2015) en la XXI Conferencia Internacional sobre Cambio Climático celebrada en París en 2015 sentó bases de acciones tendientes a frenar la contaminación ambiental y el impacto negativo. Argentina adhiere al convenio y se propone una meta de reducción de sus emisiones de gases de efecto invernadero (GEI) un 15% en el año 2030 con respecto a las emisiones proyectadas en su Business as usual (BAU) al mismo año (INDC,2015). Una de estas acciones es la creación del programa Generacioón Eléctrica a partir de fuentes Renovables (GENREN), y la reglamentación de las Leyes 26.190 (2006) y 26.191 (2016) sobre el “Régimen de Fomento Nacional para el Uso de Fuentes Renovables de Energía destinadas a la Producción de Energía Eléctrica’. Se establece que en el plazo de 10 años, el 8% del consumo eléctrico tiene que ser abastecido a partir de fuentes de energías renovables.Fil: Sánchez, G. Universidad Nacional de Córdoba. Facultad de Arquitectura, Urbanismo y Diseño; ArgentinaFil: Calvo, L. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gatani, M. Universidad Nacional de Córdoba. Facultad de Arquitectura, Urbanismo y Diseño; ArgentinaFil: Gatani, M. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ávalos, S. Universidad Nacional de Córdoba. Facultad de Arquitectura, Urbanismo y Diseño; ArgentinaFil: Molina, M. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Introducing Automated Reasoning in Network Management

This paper proposes the adoption of Artificial Intelligence techniques in the field of network management and monitoring. In order to allow automated reasoning on networking topics, we constructed an accurate ontological model capable of fitting as more as possible networking concepts. The thoroughly representation of the domain knowledge is used by a Logical Reasoner, which is an expert system capable of performing management tasks typically executed by human experts. The Logical Reasoner is integrated in a distributed multi-agent architecture for network management, which exploits the dynamic reasoning capabilities of the Situation Calculus formalism to provide a powerful system capable of performing high-level management tasks in order to deal with network fault situations. The system exploits programmable network technology to make possible the deployment of code which implements teleo-reactive agents, distributed across the whole network. The information related to network events, generated by programmable sensors deployed on the network devices, is collected by the logical entity where it is merged with general domain knowledge, with a view to identifying the root causes of faults, and to decide on reparative actions

An Efficient Retransmission Strategy for Data Gathering in Wireless Sensor Networks Authors

This paper introduces a new strategy for data gathering in wireless sensor networks that takes into account the need for both energy saving and for a reasonable tradeoff between robustness and efficiency. The proposed algorithm implements an efficient strategy for retransmission of lost packets by discovering alternative routes and making clever use of multiple paths when necessary; in order to do that we use duplicate and order insensitive aggregation functions, and by taking advantage of some intrinsic characteristics of the wireless sensor networks, we exploit implicit acknowledgment of reception and smart caching of the data