Wireless HROV Control with Compressed Visual Feedback Using Acoustic and RF Links

Underwater cooperative robotics offers the possibility to perform challenging intervention applications, such as recovering archeological objects as within the context of the MERBOTS research project, or grasping, transporting and assembly of big objects, using more than one mobile manipulator, as faced by the TWINBOT project. In order to enhance safety during the intervention, it is reasonable to avoid the umbilical, also giving more mobility to the robots, and enabling a broader set of cooperative movements. Several solutions, based on acoustic, radiofrequency (RF) or Visual Light Communication (VLC) have been proposed for underwater communications in the literature. This paper presents the architecture of an underwater wireless communication framework for the control of multiple semi-autonomous robots in cooperative interventions. The proposed framework is composed of several modules as the virtual reality interface using UWSim, the Underwater Multi-robot Cooperative Intervention Remote Control Protocol (UMCI-RCP) and a Generic Link Layer (GLL). UMCI-RCP allows the control of an underwater robot over limited communication links. UMCI-RCP integrates a progressive compression algorithm that provides visual feedback at a constant rate and ensures image reception even in channels with loses. The Time Division Multiple Access (TDMA) medium access strategy minimizes the jitter of transmitted packets. The GLL has been designed in order to provide support for multimodal transmission (i.e. acoustic, RF and VLC) and also to interface with the UWSim-NET simulator so that facilitates the experimentation either with a real or with a simulated modem. The possibility of exchange real and simulated devices in the proposed framework are demonstrated by means of a teleoperation experiment with a BlueROV equipped with the S100 RF modems. Hardware-In-the-Loop (HIL) capabilities are demonstrated repeating the experiment with the real modems and modeling the BlueROV, and also modeling both the modems and the BlueROV

Merbots project: overal description, multisensory autonomous perception and grasping for underwater robotics interventions

[Abstract] The MERBOTS project is, at the moment of writing the present article, in its third year, and have already obtained most of the expected results, from both lab and sea field trials. The project is being coordinated by the Jaume I University (i.e. IRS Lab), jointly with the University of Girona (i.e. CIRS Lab), and University of Balearic Island (i.e. SRV Group). Recent results demonstrate the viability to perform semi-autonomous cooperative interventions in underwater scenarios for archaeological applications. In this paper, first of all an overall description of the project is given, and then some results belonging to the UJI subproject are explained in more detail, such as communications and, in a more detailed manner, the autonomous perception and grasping modules.Ministerio of Economía y Competitividad; DPI2014-57746-C3-1-RGeneralitat Valenciana; GVA-PROMETEO/2016/066Universitat Jaume I; P1-1B2015-6

Comparación entre la respuesta de la actividad muscular lumbar en plataforma vibratoria y en ejercicio clásico de squat isométrico en 30º y 60º. (A comparison of the lumbar muscle activity responsein 30º and 60º isometric squat between whole-body vibration and a classic exercise).

<p align="justify">Whole-body vibration (WBV) has improved as a variety of exercises, so it is necessary know muscles responses to the vibration stimulus.The aim of this work was to study and to compare the change in muscle activation in the lumbar area and lower body between the whole-body vibration exercise and classic strength exercises in isometric squat.23 subjects were exposed to six different loads in one of each exercise mode: vibration or classic strength. Both exercises were performed at 30º and 60º semi-squat position. Muscle activity of the lower body and lumbar area was measured using surface electromyography activity (EMG).The results showed that the response of lumbar area in WBV was lower than in the classic strength exercise at the same value of lower body sEMG. Lumbar sEMG was highest for the classic exercise. Moreover, during 30º squat sEMG was higher than during 60ºsquat.</p>Resumen<p align="justify">El aumento del uso de la plataforma vibratoria como forma de realizar ejercicio conlleva la necesidad de conocer las respuestas musculares al estímulo de la misma.El objetivo de este trabajo ha sido estudiar y comparar la respuesta de la activación muscular de la zona lumbar y del tren inferior en el trabajo de plataforma vibratoria con el trabajo clásico de fuerza en un squat isométrico.23 sujetos fueron sometidos a 6 condiciones de vibración y a 6 de un trabajo clásico de pesas. Se analizó la sEMG del tren inferior y de la zona lumbar en un trabajo isométrico de un squat con flexión de 30º y 60º de rodilla.Los resultados muestran que para un mismo valor de sEMG del tren inferior, los valores de sEMG de la zona lumbar son menores en el ejercicio vibratorio. Existiendo en el trabajo de pesas una mayor exigencia en la zona lumbar. Además, con una flexión de 30º la activación muscular es mayor en todas las condiciones. (p<0,05)</p

Underwater Wireless Communications for Cooperative Robotics with UWSim-NET

The increasing number of autonomous underwater vehicles (AUVs) cooperating in underwater operations has motivated the use of wireless communications. Their modeling can minimize the impact of their limited performance in real-time robotic interventions. However, robotic frameworks hardly ever consider the communications, and network simulators are not suitable for HIL experiments. In this work, the UWSim-NET is presented, an open source tool to simulate the impact of communications in underwater robotics. It gathers the benefits of NS3 in modeling communication networks with those of the underwater robot simulator (UWSim) and the robot operating system (ROS) in modeling robotic systems. This article also shows the results of three experiments that demonstrate the capabilities of UWSim-NET in modeling radio frequency (RF) and acoustic links in underwater scenarios. It also permits evaluating several MAC protocols such as additive links online Hawaii area (ALOHA), slotted floor acquisition multiple access (S-FAMA) and user defined protocols. A third experiment demonstrated the excellent capabilities of UWSim-NET in conducting hardware in the loop (HIL) experiments

The validity and reliability of a new instrumented device for measuring ankle dorsiflexion range of motion

PURPOSE/BACKGROUND: A restriction in ankle dorsiflexion range of motion (ROM) has been linked to several clinical manifestations such as metatarsalgia, heel pain, nerve entrapment, ankle joint equinus, patellar and ankle injuries. The purpose of the present study was to examine the validity and reliability of the Leg Motion system for measuring ankle dorsiflexion ROM. STUDY DESIGN: Descriptive repeated-measures study. METHODS: Twenty-six healthy male university students were recruited to test the reliability of the Leg Motion system, which is a portable tool used for assessment of ankle dorsiflexion during the weight-bearing lunge test. The participants were tested two times separated by two weeks and measurements were performed at the same time of the day by the same single rater. To test the validity of the Leg Motion system, other maximal ankle dorsiflexion ROM assessments (goniometer, inclinometer and measuring tape) were measured in a single session (i.e., the first test session) during the weight-bearing lunge position using a standard goniometer, a digital inclinometer and a measuring tape measure with the ability to measure to the nearest 0.1 cm. RESULTS: Paired t-tests showed the absence of significant differences between right and left limb measurements of dorsiflexion in all tests. Mean values ± standard deviations were as follows: Leg Motion test (left 11.6cm±3.9; right 11.9cm ±4.0), tape measure (left 11.6cm±4.0; right 11.8cm±4.2), goniometer (left 40.6º±5.2; right 40.6º±5.2), and digital inclinometer (left 40.0º±5.8; right 39.9º±5.6). The Leg Motion composite values (i.e., average of the two legs) showed a significant (p<0.05) positive correlation with the tape measure (r=0.99), with the goniometer (r=0.66), and with the digital inclinometer (r=0.72). CONCLUSIONS: The results of the present study provide evidence to support the use of the Leg Motion system as a valid, portable, and easy to use alternative to the weight-bearing lunge test to assess ankle dorsiflexion ROM in healthy participants

State of the Art in Control Systems for Cooperative Distributed Mobile Robots in a Healthcare Environment

[Abstract] In this article we are presenting the state of the art in robotic control systems for healthcare environments. First, we identify the motivation and needs for healthcare robots in the state of the art, then we present an analysis of the challenges for their implementation, the existing solutions presented in literature and their limitations, and finally, our motivation and proposed future contribution in the field. The future work will involve the design of a robust robotic control system architecture for cooperative distributed systems of mobile manipulators used in hospital environments, as well as the validation of the control strategies in a simulated environment. The most promising solutions will be deployed on prototype mobile manipulators and validated in testing environments and, if possible, in real environments.Financed by PID2020-115332RBC31 (COOPERAMOS), IDIFEDER/2018/013 (GV), UJI-AUDAZ, and H2020-Peacetolero-NFRP-2019-2020-04 projectshttps://doi.org/10.17979/spudc.978849749841

Muscle Activation in Middle-Distance Athletes with Compression Stockings

The aim of this study was to evaluate changes in electromyographic activity with the use of gradual compression stockings (GCSs) on middle-distance endurance athletes’ performance, based on surface electromyography measurement techniques. Sixteen well-trained athletes were recruited (mean ± SD: age 33.4 ± 6.3 years, VO2max 63.7 ± 6.3 mL·kg−1·min−1, maximal aerobic speed 19.7 ± 1.5 km·h). The athletes were divided into two groups and were assigned in a randomized order to their respective groups according to their experience with the use of GCSs. Initially, a maximum oxygen consumption (VO2max) test was performed to standardize the athletes’ running speeds for subsequent tests. Afterward, electromyographic activity, metabolic, and performance variables for each group were measured with surface electromyography. In addition, blood lactate concentration was measured, both with and without GCSs, during 10 min at 3% above VT2 (second ventilatory threshold), all of which were performed on the track. Next, surface electromyography activity was measured during a 1 km run at maximum speed. No significant changes were found in electromyography activity, metabolic and performance variables with GCSs use (p > 0.164) in any of the variables measured. Overall, there were no performance benefits when using compression garments against a control condition

VNUML vs GNS3 en el desarrollo de laboratorios de redes virtuales

El aprendizaje práctico de redes de computadores es reconocido como un proceso crítico que permite a los estudiantes consolidar los conceptos introducidos en las lecciones teóricas. En este sentido, las tecnologías de virtualización están adquiriendo gran relevancia debido a que permiten desarrollar laboratorios de redes de computadores con un reducido coste de despliegue y gestión. Este artículo presenta un análisis comparativo entre GNS3 y VNUML, que son herramientas de virtualización open-source que han sido empleadas para el desarrollo de laboratorios de red virtuales para llevar a cabo el proceso de enseñanza-aprendizaje en las asignaturas Arquitectura de Redes y Arquitectura de Redes Avanzadas del Grado en Ingeniería Informática impartido en la Universidad de Murcia. El estudio presenta las principales ventajas y/o deficiencias de cada herramienta tanto para profesores como alumnos y se identifican los escenarios en los que parece más adecuada su utilización.SUMMARY -- The practical learning of computer networks is known to be a critical process in order to allow students to consolidate the concepts introduced in theoretical lessons. In this sense, virtualization technologies are becoming popular since they allow to set up a computer network laboratory with a reduced deployment and management cost. This paper presents a comparative analysis performed between GNS3 and VNUML, which are open-source tools for virtualization that have been used for developing virtual network laboratories that support the teaching-learning process in the Networks Architecture and Advanced Networks Architecture subjects of the Computer Engineering degree at the University of Murcia. The study presents the main advantages and/or deficiencies of each tool not only for professors but also for students and identifies the scenarios where the use of each tool seems to be more appropriate.Peer Reviewe

Demographic limitation processes

20 páginas, 2 figuras, 1 tabla, 3 cuadros.-- Editor: Valladares, F.[ES]: Procesos de limitación demográfica. Este capítulo ofrece una revisión de los factores que afectan a la regeneración natural de la vegetación, considerando la serie de etapas demográficas que determinan la dinámica demográfica de una pobla- ción. Son muy escasos los estudios disponibles que analizan toda la serie de eventos concatenados entre la producción de flores y frutos y el establecimiento exitoso de una planta adulta reproductiva. También son escasos los trabajos que permiten establecer los efectos aplazados que tienen las interacciones con animales a lo largo del ciclo de regeneración. La aproximación que proponemos cuantifica las pérdidas de propágulos en cada etapa demográfica e identifica “cuellos de botella” del reclutamiento que pue- den colapsar la regeneración natural de una especie. Revisamos una serie de casos de estudio que ilustran diversos procesos de limitación demográfica. El uso de técnicas explícitamente demográficas es fundamental para comprender la evolución de las especies forestales Mediterráneas y para diseñar actuaciones de preservación de sus poblaciones y de su extraordinaria diversidad.[EN]: We review the main factors influencing recruitment limitation in Mediterranean woody species by considering the sequential stages that determine the demographic cycle. Very few studies examine the whole set of demographic stages, from flower production to the successful establishment of adult reproductive plants, and their influence on recruitment. There are also few studies exploring the delayed effects of animal interactions throughout the regeneration cycle, but the information on stage-specific effects is more detailed. We propose an approach that quantifies the propagule losses at each sequential demographic stage and identifies demographic bottlenecks that might collapse population growth. We review a series of case studies illustrating different limitation processes. The use of explicit demographic techniques is central to understand the evolution of Mediterranean woody species and to design sound, ecologically-based, conservation plans to preserve their extraordinary diversity.Juan Arroyo agradece la financiación otorgada a los proyectos 4474-91 (National Geographic Society), PB 91-0894, PB95-0551, 1FD97-0743-CO3-03, PB98-1144, BOS200307924-CO2-01 (MECD, MCyT). Los trabajos de Pedro Jordano han sido financiados con proyectos MECD y MCyT (1FD97-0743-CO3-01, PB 96-0857, BOS2000-1366-C02-01 y REN2003-00273), así como la Junta de Andalucía (PAI). Juan Luis García-Castaño estuvo financiado durante su período pre-doctoral con una beca FPU, AP96-27318040. El trabajo de Fernando Pulido ha sido parcialmente financiado por una beca FPI de la Junta de Extremadura y los proyectos regional IPR-0A050 y estatal BOS2002- 12222-E del Ministerio de Ciencia y Tecnología. Los trabajos de Patricio García-Fayos han sido financiados con proyectos MCyT (1FD97-0551), de la Generalitat Valenciana (02-046) y de la Institució Alfons el Magnánim (02-046)Peer reviewe