ADMP: an adaptive multicast routing protocol for mobile ad hoc networks

We present ADMP, the adaptive mesh-based multicast routing protocol, in which nodes are able to independently tune the amount of redundancy used to transmit data packets with the goal of improving the overall packet delivery ratio while keeping the retransmission overhead as low as possible. ADMP is based on a novel distributed algorithm for computing connected dominating sets. ADMP uses a single type of control packet, called multicast announcement, which is used to build the meshes of multicast groups, elect the core of each mesh and obtain two-hop neighborhood information. Using detailed simulations for different scenarios, we show that ADMP achieves similar or better reliability than two mesh-based multicast protocols that are very resilient (ODMRP and PUMA) while inducing low packet retransmission overhead.1st IFIP International Conference on Ad-Hoc NetWorkingRed de Universidades con Carreras en Informática (RedUNCI

ADMP: an adaptive multicast routing protocol for mobile ad hoc networks

We present ADMP, the adaptive mesh-based multicast routing protocol, in which nodes are able to independently tune the amount of redundancy used to transmit data packets with the goal of improving the overall packet delivery ratio while keeping the retransmission overhead as low as possible. ADMP is based on a novel distributed algorithm for computing connected dominating sets. ADMP uses a single type of control packet, called multicast announcement, which is used to build the meshes of multicast groups, elect the core of each mesh and obtain two-hop neighborhood information. Using detailed simulations for different scenarios, we show that ADMP achieves similar or better reliability than two mesh-based multicast protocols that are very resilient (ODMRP and PUMA) while inducing low packet retransmission overhead.1st IFIP International Conference on Ad-Hoc NetWorkingRed de Universidades con Carreras en Informática (RedUNCI

Entropy-Based Channel Access Control for S-ALOHA in Wireless Ad-Hoc Networks

[EN] In this paper we present a novel cross-layer medium access control scheme that uses information about the network topology in order to select the adequate transmission probability at the individual nodes. In the proposed Entropy-based Medium Acess Control protocol (EbMAC), the probability of accessing the channel of each node is a function of the topological network entropy and their individual probability of being selected as relay in an end-to-end path computed by the routing algorithm. The topological network entropy measures the ability of the network to distribute the data traffic among the nodes. High values of network entropy indicate that the data trac will tend to concentrate around particular regions of the network and hence, that these regions are more likely to experience contention. In this case, the channel access probability has to be selected in such a way as to reduce the packet collision probability in such hot spots. Simulation-based experiments show that the proposed scheme attains performance gains in terms of throughput, collisions ratio and end-to-end delay.[ES] En este artículo presentamos un nuevo enfoque de acceso al medio de capa cruzada que utiliza información topológica de la red para seleccionar la probabilidad de transmisión de cada nodo. En el esquema propuesto, la probabilidad de acceder al canal es asignada en función tanto de la entropía topológica de la red, como de la probabilidad individual de cada nodo de ser elegido por el algoritmo de enrutamiento como retransmisor en un flujo de datos de extremo-a-extremo. La entropía topológica de la red mide la capacidad de dicha red para distribuir el tráfico entre los nodos que la componen. Valores de entropía baja indican que el tráfico tenderá a concentrarse en regiones particulares de la red y que por lo tanto la probabilidad de que los nodos localizados en dichas regiones experimenten contención, es alta. En este caso, la probabilidad de acceso al medio de los nodos que se encuentran en esas regiones deberá ser seleccionada de forma tal que se reduzca la probabilidad de que experimenten contención. Experimentos de simulación muestran que el esquema propuesto logra ganancias de desempeño en términos del caudal, la probabilidad de experimentar colisiones y el retardo extremo-a-extremo.González-Ambriz, SJ.; Rivero Angeles, ME.; Menchaca-Méndez, R.; Menchaca-Méndez, R. (2019). Control de Acceso al Medio basado en Entropía para S-ALOHA en Redes Inalámbricas Ad-Hoc. Revista Iberoamericana de Automática e Informática. 16(2):178-189. https://doi.org/10.4995/riai.2018.10398SWORD17818916

Chlamydia trachomatis y Neisseria gonorrhoeae: prevalencia y relación con los datos clínicos de vaginitis

Antecedentes: estudios previos indican que la C. trachomatis y la N. gonorrhoeae son bacterias con alta prevalencia debido a que causan pocos síntomas y no se estudian específi camente. Objetivo: comparar la prevalencia de C. trachomatis y N. gonorrhoeae en mujeres con síntomas de vaginitis y asintomáticas. Pacientes y métodos: se estudiaron 200 pacientes y se dividieron en dos grupos: 100 mujeres con vaginitis y 100 mujeres asintomáticas. Se preguntó la edad, edad de inicio de vida sexual, portadoras de DIU, antecedente de vaginitis de repetición (tres veces o más en un año) y las características del endocérvix. Se tomaron dos muestras de secreción del endocérvix. La C. trachomatis se estudió con el estuche comercial MicrotraK Chlamydia trachomatis directa (Trinity Biotech, USA). Para la N. gonorrhoeae se hicieron cultivos en medio de agar chocolate y agar Thayer Martin. El análisis estadístico con la χ2. Resultados: La C. trachomatis se detectó en 40 mujeres con vaginitis y en 17 de las asintomáticas. No se aisló N. gonorrhoeae. Sólo el29% de las Chlamydia positivas tenía menos de 25 años. No hubo diferencia estadística entre C. trachomatis y el inicio temprano de la vida sexual y el uso de DIU. En 72 hubo el antecedente de vaginitis de repetición, con 46.7% de Chlamydia positivas, y 28% de las que no lo tenían (p < 0.01). De 69 con el endocérvix sangrante, 37 fueron positivas a C. trachomatis; en 131 sin alteraciones en endocérvix, sólo 20 tuvieron C. trachomatis (p < 0.01). Conclusiones: No encontramos N. gonorrhoeae. La C. trachomatis fue más frecuente en mujeres con síntomas de vaginitis, vaginitis de repetición y endocérvix sangrante

Role of the polymorphic IL-1B, IL-1RN and TNF-A genes in distal gastric cancer in Mexico

Several cytokine gene polymorphisms have been associated with increased risk of distal gastric cancer (GC) and its precursor histological markers in Caucasian, Asian and Portuguese populations although little is known about their role in other ethnic groups. Our study investigates the role of the IL-1B-31, IL-1RN and TNF-A-308 gene polymorphisms as risk factors for the development of GC in a Mexican population. We studied 278 patients who were enrolled at the Hospital Universitario Dr. José Eleuterio González, Universidad Auto´noma de Nuevo Leo´n. The subjects were divided into 2 groups. Sixty-three patients with histologically confirmed distal GC (mean age 58.8 years, range 22–84, F:M 0.56), and 215 patients with no evidence of distal or proximal GC (mean age 56.1 years, range 18–92, F:M 1.17). The IL-1B-31 and the TNF-A-308 polymorphisms were determined by PCR-RFLP and pyrosequencing, respectively, in all cases and controls. The VNTR polymorphism in intron 2 of the 1L-1RN gene was typed by PCR in 25 cases and 201 controls. The H. pylori status was determined by histology, rapid urease test, culture and serology for non-cancer controls and by histology for the GC cases. The carriage of the proinflammatory IL-1B-31*Callele was associated with increased risk of distal GC (odds ratio [OR] 7.63, 95% confidence interval [CI] 1.73-46.94, p 0.003). When cases and controls were matched by age and gender, the OR value was higher (OR 8.05, 95% CI 1.8 –50.22, p 0.001). When only H. pylori GC cases and controls were compared, the OR value was 7.8 (95% CI 1.05–161.8, p 0.04). No association was found between any of the other polymorphisms studied and distal GC. In this Mexican population, the IL-1B proinflammatory genotype increases the risk of distal GC. These findings are similar to previous reports in Caucasian populations and underscore the importance of cytokine gene polymorphisms in the development of distal GC

Hypocholesterolemia in patients with an amebic liver abscess

Background/Aims: Many parasites induce changes in the lipid profiles of the host. Cholesterol increases the virulence of Entamoeba histolytica in animal models and in vitro culture. This study aimed to determine, in patients with an amebic liver abscess, the correlation between cholesterol and other features, such as the size and number of abscesses, standard hematological and serum chemistry profiles, liver tests, and duration of hospital stay. Methods: A total of 108 patients with an amebic liver abscess and 140 clinically healthy volunteers were investigated. Cholesterol and triglycerides were measured in the sera. The data from medical observations and laboratory tests were obtained from the clinical records. Results: A total of 93% of patients with an amebic liver abscess showed hypocholesterolemia not related to any of the studied parameters. Liver function tests correlated with the size of the abscess. The most severe cases of amebic liver disease or death were found in patients whose cholesterol levels continued to decrease despite receiving antiamebic treatment and hospital care. Conclusions: Our results show that the hypocholesterolemia observed in patients with an amebic liver abscess is not related to any of the clinical and laboratory features analyzed. This is the first study relating hypocholesterolemia to severity of hepatic amebiasis

Opportunistic Mobile Sensing in the Fog

The increasing adoption of mobile personal devices and Internet of Things devices is leveraging the emergence of a wide variety of opportunistic sensing applications. However, the designers of this type of applications face a set of technical challenges related to the limitations and heterogeneity of the hardware and software platforms and to the dynamics of the scenarios where they are deployed. In this paper, we introduce a Semantic-Centric Fog-based framework aimed at effectively and efficiently supporting this type of applications. The proposed framework is composed of local and distributed algorithms that support the establishment and coordination of sensing tasks in the Fog. First, it performs ontology-driven in-network processing to locate the most adequate devices to carry out a given sensing task and then, it establishes efficient multihop routes that are used to coordinate relevant devices and to transport the collected sensory data to Fog sinks. We present a set of theorems that prove that the proposed algorithms are correct and the results of a series of detailed simulation-based experiments in NS3 that characterize the performance of the proposed platform. The results show that the proposed framework outperforms traditional sensing platforms that are based on centralized services

Java RMI

ArtículosEn el presente artículo se describe la arquitectura de una de las principales alternativas para el desarrollo de aplicaciones basadas en objetos distribuidos, Java RMI. Además se presenta de manera detallada un ejemplo donde se muestra una de las adiciones más significativas al modelo de objetos distribuidos de Java en su versión 1.2 con respecto a la 1.1, la capacidad de activar "sobre demanda" a los objetos remotosThis paper describes the architecture of Java RMI that is one of the main alternatives for the developing of applications based on distributed objects. Also we develop a detailed example of activation on demand of distributed objects that is one of the most significant improvements introduced in the JDK 1.

Java RMI

En el presente artículo se describe la arquitectura de una de las principales alternativas para el desarrollo de aplicaciones basadas en objetos distribuidos, Java RMI. Además se presenta de manera detallada un ejemplo donde se muestra una de las adiciones más significativas al modelo de objetos distribuidos de Java en su versión 1.2 con respecto a la 1.1, la capacidad de activar "sobre demanda" a los objetos remotos

Arquitectura de la Máquina Virtual Java

ArtículosEn el presente artículo se describe la Arquitectura de la Máquina Virtual Java, que es parte medular de toda la tecnología Java. Se hace énfasis en sus componentes principales, como el procesador virtual Java, que se encarga de ejecutar los códigos de operación (bytecodes) generados por los compiladores Java, el verificador de código, que junto con el cargador de clases y el administrador de seguridad, se encargan de implementar los mecanismos empleados para proporcionar seguridad a los usuarios de Java. Además, a lo largo de la discusión, se hace un análisis de las principales características que han hecho posible el éxito de Java en nuestros díasThe present article describes the architecture of the Java virtual machine that is one of main components of the Java technology. We focus in its main components such as the Java virtual processor that executes the operation codes (bytecodes) generated by the Java compilers, the code verifier that along with the class loader and the security manager implement the Java security mechanisms. We analyze the main characteristics that have made possible the Java success in our day