The phase noise effect in multiple-input-multiple-output systems employing orthogonal frequency division multiplexing is considered in a realistic scenario where the estimated channel matrix is ...affected by an error. The analytical SINR degradation due to phase noise and channel estimation is obtained for linear receivers (ZF and MMSE).
Future brain-machine interfaces, prosthetics, and intelligent soft robotics will require integrating artificial neuromorphic devices with biological systems. Due to their poor biocompatibility, ...circuit complexity, low energy efficiency, and operating principles fundamentally different from the ion signal modulation of biology, traditional Silicon-based neuromorphic implementations have limited bio-integration potential. Here, we report the first organic electrochemical neurons (OECNs) with ion-modulated spiking, based on all-printed complementary organic electrochemical transistors. We demonstrate facile bio-integration of OECNs with Venus Flytrap (Dionaea muscipula) to induce lobe closure upon input stimuli. The OECNs can also be integrated with all-printed organic electrochemical synapses (OECSs), exhibiting short-term plasticity with paired-pulse facilitation and long-term plasticity with retention >1000 s, facilitating Hebbian learning. These soft and flexible OECNs operate below 0.6 V and respond to multiple stimuli, defining a new vista for localized artificial neuronal systems possible to integrate with bio-signaling systems of plants, invertebrates, and vertebrates.
We present a new approach to nonparametric spectral estimation on the basis of the support vector method (SVM). A reweighted least squares error formulation avoids the computational limitations of ...quadratic programming. The application to a synthetic example and to a digital communication problem shows the robustness of the SVM spectral analysis algorithm.
Feet-ground interactions influence the legged robot's stability. In this paper, a high-resolution indirect force measurement for hydraulic-legged robots is presented. The use of pressure transducers ...placed at one or both chambers of the robot's double-effect hydraulic actuators is investigated, and conclusions are drawn regarding their capability for indirectly measuring the contact forces between the feet and the ground. Because of the nonlinear dynamic properties of hydraulic cylinders, friction modeling is essential to determine at all times the true forces of each foot against the soil. The test case is called ROBOCLIMBER, which is a bulky quadruped climbing and walking machine able to carry heavy-duty drilling equipment for landslide consolidation and monitoring works. Sensor calibration and signal filtering requirements are also taken into consideration. To end, the overall proposed approach to measure feet-ground interactions is experimentally evaluated.
The aim of the study was to compare the maximal physiological responses during three protocols: maximal test on land cycle ergometer, maximal test on water cycling in an indoor pool at 27 °C (WC27) ...and at 31 °C (WC31). Moreover, the submaximal physiological responses were compared according cycling cadences and water temperatures during the water protocols. Ten young men were included and performed the protocols in separate days. Blood lactate (BL) concentration, heart rate (HR), oxygen uptake (
O
2
), ventilation (VE) and thermal comfort (TC) were collected during the exercise. The maximal HR and
O
2
showed no significant differences between the protocols: HR
max
: 189±7 (Land), 188±14 (WC27), 185±9 bpm (WC31) and
O
2max
: 4.2±0.4 (Land), 4.1±0.5 (WC27) and 4.3±0.5 l min
−1
(WC31). However, the maximal BL demonstrated significant lower values during the water protocols compared to the land protocol (p=0.018). All the submaximal physiological responses showed significant differences between the cadences (60, 70, 80 and 90 rpm). The effect of water temperature was significant for TC response (p=0.001) showing higher values at 31 °C than 27 °C (TC
W27
: 7±1 and TC
W31
:9±1). In conclusion, higher physiological responses were showed by increasing the cadence by 10 rpm and the subjects were more comfortable when cycling in the lower water temperature.
To evaluate the efficacy of manual lymphatic drainage (MLD) in improving health-related quality of life (HRQOL), symptomatology, and physical status in patients with chronic venous insufficiency ...(CVI).
Single-blind randomized controlled trial.
Health community attendant service.
Subjects with CVI (N=41) were randomly assigned to an experimental group (n=20; mean age, 54.6±11.3y) or control group (n=21; mean age, 46.8±11.1y).
The experimental group completed 10 lower extremity MLD sessions over 4 weeks and 1 educational session. The control group only attended the educational session. Outcome measures were taken at baseline (t0), at the end of 4 weeks (t1), and after 2 months for follow-up (t2).
HRQOL was assessed with the Chronic Venous Insufficiency Quality of Life Questionnaire-20, symptoms (fatigue, heaviness) were assessed with a visual analog scale, severity of the disease was assessed with the Venous Clinical Severity Score (VCSS) (total score, score for each item), leg volumetry was assessed with perimeters, and plantar/dorsiflexion strength and ankle range of motion (ROM) were assessed with dynamometry.
A significant interaction group×time effect was found for pain on HRQOL (F2,78=3.507; P=.035; partial η2=.087), clinical severity (F2,78=5.231; P=.007; partial η2=.118), especially for venous edema (assessed with the VCSS), fatigue (F1.67,65.21=4.690; P=.012; partial η2=.107), and heaviness (F1.57,61.32=9.702; P=.001; partial η2=.199), with the experimental group improving from t0 to t1 and t0 to t2 in all of these outcomes. No effect of MLD treatment could be found for ankle muscle strength, ankle ROM, and leg volume.
Short-term MLD treatment ameliorates CVI severity and related edema, symptoms, and pain HRQOL in patients with CVI.
Detection and removal of antipersonnel landmines is an important worldwide concern. A huge number of landmines has been deployed over the last twenty years, and demining will take several more ...decades, even if no more mines were deployed in future. An adequate mine-clearance rate can only be achieved by using new technologies such as improved sensors, efficient manipulators and mobile robots. This paper presents some basic ideas on the configuration of a mobile system for detecting and locating antipersonnel landmines efficiently and effectively. The paper describes the main features of the overall system, which consists of a sensor head that can detect certain landmine types, a manipulator to move the sensor head over large areas, a locating system based on a global-positioning system, a remote supervisor computer and a legged robot used as the subsystems' carrier. The whole system has been configured to work in a semi-autonomous mode with a view also to robot mobility and energy efficiency.
Abstract Introduction Muscle thickness (MT) and muscle echo-intensity (EI) allow the study of skeletal muscle adaptive changes with ultrasound. This study investigates the intra- and inter-session ...reliability and agreement of MT and EI measurements for each of the four heads of the quadriceps femoris in transverse and longitudinal scans, using two sizes for the region of interest (ROI); EI measurements only. Methods Three B-mode images from two views were acquired from each head of quadriceps femoris from twenty participants (10 females) in two sessions, 7 days apart. EI was measured using a large and a small ROI. Reliability was examined with the mixed two-way intra-class correlation coefficient (ICC), the standard error of mean (SEM) and the smallest detectable change (SDC). Bland–Altman's plots were used to study agreement. Results High to very high inter-session ICC values were found for MT for all muscle heads, particularly for measurements from transverse scans. For EI measurement, ICC values ranged from low to high, with higher ICC values seen with the largest ROI. SDC values ranged between 0.19 and 0.53 cm for MT and between 3.73 and 18.56 arbitrary units (a.u.) for two ROIs. Good agreement existed between MT measurements made in both scans. A small bias and larger 95% limits of agreement were seen for EI measurements collected with the two ROI sizes. Conclusion Ultrasound measures of MT and EI show moderate to very high reliability. The reliability and agreement of MT and EI measurements are improved in transverse scans and with larger ROIs.
An approach for achieving reliable, built-in, high-accuracy force sensing for legged robots is presented, based on direct exploitation of the properties of a robot’s mechanical structure. The ...proposed methodology relies on taking account of force-sensing requirements at the robot design stage, with a view to embedding force-sensing capability within the mechanical structure of the robot itself. The test case is ROBOCLIMBER, a bulky, quadruped climbing and walking machine whose weighty legs enable it to carry out heavy-duty drilling operations. The paper shows that, with finite-element analysis of ROBOCLIMBER’s mechanical configuration during the design stage, candidate positions can be selected for the placement of force transducers to measure indirectly the contact forces between the feet and the ground. Force sensors are then installed at the theoretically best positions on the mechanical structure, and several experiments are carried out to calibrate all sensors within their operational range of interest. After calibration, the built-in sensors are subjected to experimental performance evaluation, and the final best sensor option is found. The built-in force-sensing capability thus implemented is subjected to its first test of usability when it is employed to compute the actual centre of gravity of ROBOCLIMBER. The method is shown to be useful for determining variation during a gait (due to the non-negligible weight of the legs). Afterwards the force sensors are shown to be useful for controlling foot-ground interaction, and several illustrative experiments confirm the high sensitivity, reliability and accuracy of the selected approach. Lastly, the built-in sensors are used to measure ground-reaction forces and to compute the zero-moment point for ROBOCLIMBER in real time, both while standing and while executing a dynamically balanced gait.
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