Simulation analysis of IEEE 802.15.4 for wireless networked control systems

The deployment of wireless networks in industrial environments can bring several advantages over their wired counterparts; however, the characteristics of the wireless channels pose challenges to the provisioning of quality of service (QoS) that are not seen in wired networks. This paper provides an analysis of how important QoS parameters, such as message delivery ratio, delay and energy consumption, vary as a function of the number of sensor nodes injecting traffic in IEEE 802.15.4 networks operating in unbeaconed mode. Results show that the peer-to-peer topology enables better performance than the star topology, under the same conditions, indicating that the former is a better option if centralized control is not required. The use of retransmissions increases significantly the reliability of the network; however, even a high number of retransmissions are not enough to provide full reliability when the channel is highly affected by errors. Results also show that presence of hidden nodes can severely degrade the performance of the network, while the reduction of the turnaround time can improve the performance.Fundação para a Ciência e a Tecnologia (FCT

A personalized rehabilitation system based on wireless motion capture sensors

We live in an aging society, an issue that will be exacerbated in the coming decades, due to low birth rates and increasing life expectancy. With the decline in physical and cognitive functions with age, it is of the utmost importance to maintain regular physical activity,in order to preserve an individual’s mobility, motor capabilities and coordination. Within this context, thispaper describes the development of a wireless sensor network and its application in a human motion capturesystem based on wearable inertial and magnetic sensors. The goal is to enable, through continuous real-time monitoring, the creation of a personalized home-based rehabilitation system for the elderly population and/or injured people. Within this system, the user can benefit from an assisted mode, in which their movements can be compared to a reference motion model of the same movements, resulting in visual feedback alerts given by the application. This motion model can be created previously, in a ‘learning phase’, under supervision of a caregiver.Fundação para a Ciência e a Tecnologia (FCT

A telerehabilitation system based on wireless motion capture sensors

The constant growth of the elderly population in the world creates new challenges and opportunities in health care systems. New technological solutions have to be found in order to meet the needs and demands of our aging society. The welfare and quality of life of the elderly population must be a priority. Continuous physical activity will play an important role, due to the increase of the retirement age. However, physiotherapy can be expensive, even when the desire movements are autonomous and simple, also requires people to move to rehabilitation centres. Within this context, this paper describes the development and preliminary tests of a wireless sensor network, based on wearable inertial and magnetic sensors, applied to the capture of human motion. This will enable a personalized home-based rehabilitation system for the elderly or people in remote physical locations.Project “AAL4ALL”, co-financed by the European Community Fund FEDER through COMPETE – Programa Operacional Factores de Competitividade (POFC).FCT – Foundation for Science and Technology – Lisbon, Portugal, through project PEst-C/CTM/LA0025/2013

Design and implementation of a wireless sensor network applied to motion capture

This paper describes the development of a wireless sensor network prototype and its application in a motion capture system based on inertial and magnetic sensors. The system presents a portable and modular architecture and allows the monitoring of several users at the same time using a single wireless network. The target application requires the wireless sensor network to operate efficiently under high loads, since it generates data intensive traffic and needs to support a high number of sensor modules. Other requirements imposed by the application are real-time operation and reliable data delivery. In order to provide the quality of service required by the application, an enhanced version of the LPRT medium access control protocol was developed and implemented in devices compliant with the IEEE 802.15.4 standard at the physical layer. Simulation results show that the proposed modifications improve the performance of the protocol. The implementation of the protocol is validated through the experimental results presented.Fundação para a Ciência e a Tecnologia (FCT) - projeto PTDC/EEA-TEL/68625/2006

Cover Crops Alternatives for Sustainable Agriculture Systems in Uruguay

In Uruguay, the increase of cropland area during the last decade was based on rotation systems intensification and soybean expansion, achieving 1.321.000 ha (Souto, 2014). Diaz (2007) demonstrated the value of the ley-farming systems where the integration of livestock and crop production achieved benefits on sustainability. Despite the advantages of crop-pasture rotation systems (García Prechac et al., 2004), grain market prices and food demand resulted in pasture phase losses in rotation with crops. Recently, Livestock Agriculture and Fisheries Ministry implemented a national soil conservation plan, that regulates cropping rotation systems based on soil erosion estimations and other key soil quality indicators. Although, no-till was full adopted, climatic and soil conditions determine that soil must be cover by residues or vegetation all year to reduce erosion and degradation (Thorup-Kristensen et al., 2003). Cover crops contribute to protect soils during fallow periods. The 17% of total soybean area cultivated is in Eastern Uruguay, being soils with erosion risk , fertility, structure and drainage limitations. This paper evaluates cover crops adaptation, subsequent effects on soybean productivity, and estimations of nitrogen supply and extraction from cover crops and soybean, respectively

A wireless posture monitoring system for personalized home-based rehabilitation

We live in an aging society, an issue that will be exacerbated in the coming decades, due to low birth rates and increasing life expectancy. With the decline in physical and cognitive functions with age, it is of the utmost importance to maintain regular physical activity, in order to preserve an individual’s mobility, motor capabilities and coordination. Within this context, this paper describes the development of a wireless sensor network and its application in a human motion capture system based on wearable inertial and magnetic sensors. The goal is to enable, through continuous real-time monitoring, the creation of a personalized home-based rehabilitation system for the elderly population and/or injured people. Within this system, the user can benefit from an assisted mode, in which their movements can be compared to a reference motion model of the same movements, resulting in visual feedback alerts given by the application. This motion model can be created previously, in a ‘learning phase’, under supervision of a caregiver.Project “AAL4ALL”, co-financed by the European Community Fund FEDER through COMPETE – Programa Operacional Factores de Competitividade (POFC). This work is funded by FEDER funds through the COMPETE 2020 Programme and National Funds through FCT - Portuguese Foundation for Science and Technology under the projects UID/CTM/50025/2013 and UID/EEA/04436/2013.info:eu-repo/semantics/publishedVersio

Black-hole horizons as probes of black-hole dynamics II: geometrical insights

In a companion paper [1], we have presented a cross-correlation approach to near-horizon physics in which bulk dynamics is probed through the correlation of quantities defined at inner and outer spacetime hypersurfaces acting as test screens. More specifically, dynamical horizons provide appropriate inner screens in a 3+1 setting and, in this context, we have shown that an effective-curvature vector measured at the common horizon produced in a head-on collision merger can be correlated with the flux of linear Bondi-momentum at null infinity. In this paper we provide a more sound geometric basis to this picture. First, we show that a rigidity property of dynamical horizons, namely foliation uniqueness, leads to a preferred class of null tetrads and Weyl scalars on these hypersurfaces. Second, we identify a heuristic horizon news-like function, depending only on the geometry of spatial sections of the horizon. Fluxes constructed from this function offer refined geometric quantities to be correlated with Bondi fluxes at infinity, as well as a contact with the discussion of quasi-local 4-momentum on dynamical horizons. Third, we highlight the importance of tracking the internal horizon dual to the apparent horizon in spatial 3-slices when integrating fluxes along the horizon. Finally, we discuss the link between the dissipation of the non-stationary part of the horizon's geometry with the viscous-fluid analogy for black holes, introducing a geometric prescription for a "slowness parameter" in black-hole recoil dynamics.Comment: Final version published on PR

Black-hole horizons as probes of black-hole dynamics I: post-merger recoil in head-on collisions

The understanding of strong-field dynamics near black-hole horizons is a long-standing and challenging prob- lem in general relativity. Recent advances in numerical relativity and in the geometric characterization of black- hole horizons open new avenues into the problem. In this first paper in a series of two, we focus on the analysis of the recoil occurring in the merger of binary black holes, extending the analysis initiated in [1] with Robinson- Trautman spacetimes. More specifically, we probe spacetime dynamics through the correlation of quantities defined at the black-hole horizon and at null infinity. The geometry of these hypersurfaces responds to bulk gravitational fields acting as test screens in a scattering perspective of spacetime dynamics. Within a 3 + 1 approach we build an effective-curvature vector from the intrinsic geometry of dynamical-horizon sections and correlate its evolution with the flux of Bondi linear momentum at large distances. We employ this setup to study numerically the head-on collision of nonspinning black holes and demonstrate its validity to track the qualita- tive aspects of recoil dynamics at infinity. We also make contact with the suggestion that the antikick can be described in terms of a "slowness parameter" and how this can be computed from the local properties of the horizon. In a companion paper [2] we will further elaborate on the geometric aspects of this approach and on its relation with other approaches to characterize dynamical properties of black-hole horizons.Comment: final version published on PR

Project results presentation (deliverable D18)

This document is a report which collects together the CYCLOPS project results for dissemination to different interested audiences such as Grid communities and Civil Protection agencies. It also reports on national and international initiatives and projects, SMEs, training activities and related projects. The structure of this document shows the approach used in the project. Following an introduction, it describes a set of related projects, namely grid- based technologies/EGEE, risk management, and GMEs-based services. It then presents the business of Civil Protection and the use cases selected. These highlight the grid requirements for Grid-based CP applications. The research strategies and enhancements needed for the EGEE infra-structure are identified, based on the use cases. Dissemination of training and knowledge to different communities are also key points of the project.FP

Scouting Benefits and Developing Innovations in Temperate Grassland to Sustainable Agriculture Production

Agricultural intensification raises concern about land use and future effects to natural resources. The world demand for grain, meat and forest products is increasing constantly. Changes are occurring at large scale, being a compromise for policy makers to contribute to identify opportunities to readdress the productive scenario. There is available technology to reduce impacts, without restricting necessarily productivity. Grasslands provide a large series of economical and ecological benefits to the agricultural systems, being the literature exhaustive in examples. Ley-farming and cover crops technologies are good examples of environmentally sound soil management practices. The society is also worried about an improper use of the natural resources involved. The drastic increase in the grain crops area leaded by soybean in Uruguay, determined that the government implemented Sustainable Soil Use and Management Plans, based on erosion estimation using the USLE-RUSLE model adapted locally by research conducted over more than 50 years on a series of long term experimental platforms. There is an opportunity for this type of local innovative initiatives to be widely diffused, adopted or adapted. In essence, grasslands will continue playing a key role in maintaining a sustainable production