A Cross-Layer Medium Access Control and Routing Protocol for Wireless Sensor Networks

National audienceMany contention-based routing protocols in Wireless Sensor Networks (WSN) proposed so far require that the sensor node knows the location or position of all neighbors in its transmission range in order to forward packets in the geographic direction of the destination. Location awareness, gained by localization techniques such as observing beacon messages each node sends out periodically or with the help of Global Positioning System (GPS), is not practical for reasons of cost (in volume, money and power consumption). Therefore, a novel cross-layer integrated medium access control/routing protocol called RSSI-based Forwarding (RBF), based on a Received Signal Strength Indicator (RSSI) as a routing parameter, is proposed for multi-hop WSN. Without using prior knowledge of nodes' geographical locations and without maintaining neighborhood routing tables, the next-hop node for data-forwarding task is determined at the same time as the contention process among the possible forwarding nodes is solved. For an arriving beacon signal transmitted by the sink, received power levels are computed for each sensor node in the network and these levels are then used as a decision parameter for the nodes to contend for the forwarding task of the data packets. Simulation results are presented to evaluate the sensor nodes' end-to-end delay in transmitting the data packets towards the sink

Promoting empowerment and self-care in older women through participatory action research: Analysis of the process of change

Aim: To generate and understand the process of change in the empowerment of women from 60 to 80 years old through a Participatory Action Research. Specific aim: To analyse the women participants' experiences concerning empowerment and self-care. Design: We use the Participatory Action Research approach (in its critical option) in the Socio-critical Paradigm and applying the Kemmis and McTaggart Model. Methods: A group of 10 women participants from 60 to 80 years old was created and developed the Participatory Action Research from June 2019 to May 2020. This group was involved in 22 group sessions, individual interviews, reflective diaries and triangulation with quantitative data. Results: Findings were interpreted based on the Gestalt Self Theory. Women generated changes in their empowerment based on three characteristics (self-determination, self-esteem and self-confidence) and, consequently, in their self-care. They did so according to two distinct patterns of behaviour: Leader women and follower women. The former took the lead in transforming their realities and the latter observed them and evolved in a slower and more reflective manner. These changes had an impact on the most individual level (inner world) and went beyond that barrier, modifying in turn their immediate surroundings and the social level (outer world). Conclusions: The group of older women began to consider their needs and consider themselves as important once they worked on their self-determination, self-esteem and self-confidence; we show these are key aspects to work on their empowerment and promote their self-care. Impact: The patterns of behaviour and dimensions of empowerment detected may help in future research designs and emancipatory community interventions in this population group.S

Synthesis of Fe-Au nanoparticles through phase separation using the gas aggregation technique

During the last veers different type of magnetic materials have been obtained either alloys or nanopor-ritlcs with severall metalllics shells. These particle exhibt better magnetic properties, are biocompatible and have optical properties due to their shell noble metal layer, this is possible, to synthesize heterostructured nanoparticles with care/shell structure by using sputtering targets consisting of alloys of different materials. In the case of such materials have different surface energies and atomic sizes, there are diffusion processes which lead to the formation of structured nanoparticles with a shell and core having different composition. In this work we will show the results obtained about Fe-Au nanoparticles grown by I he gas aggregation technique, using magnetron sputering sources. Colloids prepared from sputtered deposits of heterostructed nanoparticles exhibit less aggregation when compared to suspensions obtained from pure magnetic materials. Spectrophotometry measurement show the presence of gold at the surface of the nanoparticles. Magnetic properties of such particle are analyzed by VSM. Compasition end structural analysis are studied by TEM and ÉDA

Joint modeling of arrivals and parking durations for freight loading zones: Potential applications to improving urban logistics

This paper analyzes truck parking patterns in urban freight loading zones by jointly modeling the vehicle arrival rates and the parking durations. Three models were explored: 1) Count data (Negative Binomial) for vehicle arrivals, 2) Survival (Weibull) model for parking duration and 3) A joint model for arrivals and duration. The count data model estimates the parking demand i.e., the rate of truck arrival, while the survival model estimates the probability that a truck is parked for one more minute. The joint model is compared with separate models for predictability and performance. The dataset used in this research is obtained using a mobile phone parking application, at eight loading zones in the city Vic, Spain over an 18-month period from July 2018 to December 2019, comprised of vehicle parking durations, date, time of arrival and departure, professional activity, and vehicle type (weight). The parking activity data are complemented with built in environment variables of the loading zones, such as the number of establishments in a certain radius, the average walking distance to establishments, the presence of pedestrian pavement, the number of traffic lanes, among others. The joint model outperforms the models estimating the arrival rates and durations separately in goodness of fit and predictability. The model results showed that truck arrival rates vary significantly across days of the week, months, and arrival times. The parking durations are highly dependent on professional activity, vehicle type, and size. Tuesdays and Wednesdays have higher arrival rates compared to other days of a week (except Sundays). Among activities, the transport and parcels require longer parking durations. Among the vehicle types, trucks with gross weight larger than 3.5 tons park longer. This paper concludes by explaining the potential of these modeling approaches in improving urban freight operations, evaluation of various policy implications, limitations, and future research

FPGA Implementation for Real-Time Background Subtraction Based on Horprasert Model

Background subtraction is considered the first processing stage in video surveillance systems, and consists of determining objects in movement in a scene captured by a static camera. It is an intensive task with a high computational cost. This work proposes an embedded novel architecture on FPGA which is able to extract the background on resource-limited environments and offers low degradation (produced because of the hardware-friendly model modification). In addition, the original model is extended in order to detect shadows and improve the quality of the segmentation of the moving objects. We have analyzed the resource consumption and performance in Spartan3 Xilinx FPGAs and compared to others works available on the literature, showing that the current architecture is a good trade-off in terms of accuracy, performance and resources utilization. With less than a 65% of the resources utilization of a XC3SD3400 Spartan-3A low-cost family FPGA, the system achieves a frequency of 66.5 MHz reaching 32.8 fps with resolution 1,024 × 1,024 pixels, and an estimated power consumption of 5.76 W

CCL2-Expressing Astrocytes Mediate the Extravasation of T Lymphocytes in the Brain. Evidence from Patients with Glioma and Experimental Models In Vivo

CCL2 is a chemokine involved in brain inflammation, but the way in which it contributes to the entrance of lymphocytes in the parenchyma is unclear. Imaging of the cell type responsible for this task and details on how the process takes place in vivo remain elusive. Herein, we analyze the cell type that overexpresses CCL2 in multiple scenarios of T-cell infiltration in the brain and in three different species. We observe that CCL2+ astrocytes play a part in the infiltration of T-cells in the brain and our analysis shows that the contact of T-cells with perivascular astrocytes occurs, suggesting that may be an important event for lymphocyte extravasation

Background Subtraction Based on Color and Depth Using Active Sensors

Depth information has been used in computer vision for a wide variety of tasks. Since active range sensors are currently available at low cost, high-quality depth maps can be used as relevant input for many applications. Background subtraction and video segmentation algorithms can be improved by fusing depth and color inputs, which are complementary and allow one to solve many classic color segmentation issues. In this paper, we describe one fusion method to combine color and depth based on an advanced color-based algorithm. This technique has been evaluated by means of a complete dataset recorded with Microsoft Kinect, which enables comparison with the original method. The proposed method outperforms the others in almost every test, showing more robustness to illumination changes, shadows, reflections and camouflage.This work was supported by the projects of excellence from Junta de Andalucia MULTIVISION (TIC-3873), ITREBA (TIC-5060) and VITVIR (P11-TIC-8120), the national project, ARC-VISION (TEC2010-15396), and the EU Project, TOMSY (FP7-270436)

El magnetómetro por gradiente alternante de campo: una nueva herramienta para la caracterización de nanopartículas magnéticas en biofluidos y tejidos biológicos

Las aplicaciones que ofrecen las nanopartículas magnéticas basadas en sus interacciones con los campos magnéticos estáticos o variantes en el tiempo, son uno de los principales y más prometedores focos de investigación biomédica en la actualidad. La caracterización magnética de las partículas y de su comportamiento en el interior de materiales biológicos es un aspecto susceptible de numerosas mejoras, siendo además uno de los pasos preliminares fundamentales a la realización de cualquiera de los experimentos que las empleen. En este artículo se presenta una nueva herramienta que facilitará esta tarea, además de presentar futuras líneas de acción que ofrecerán nuevas posibilidades en el mundo de la nanobioingeniería, partiendo de una breve introducción teórica en la que se presentarán los principios físicos que se encuentran en la base de las aplicaciones biomédicas de las nanopartículas. Las aplicaciones que ofrecen las nanopartículas magnéticas basadas en sus interacciones con los campos magnéticos estáticos o variantes en el tiempo, son uno de los principales y más prometedores focos de investigación biomédica en la actualidad. La caracterización magnética de las partículas y de su comportamiento en el interior de materiales biológicos es un aspecto susceptible de numerosas mejoras, siendo además uno de los pasos preliminares fundamentales a la realización de cualquiera de los experimentos que las empleen. En este artículo se presenta una nueva herramienta que facilitará esta tarea, además de presentar futuras líneas de acción que ofrecerán nuevas posibilidades en el mundo de la nanobioingeniería, partiendo de una breve introducción teórica en la que se presentarán los principios físicos que se encuentran en la base de las aplicaciones biomédicas de las nanopartículas