23 research outputs found
Control of A High Performance Bipedal Robot using Viscoelastic Liquid Cooled Actuators
This paper describes the control, and evaluation of a new human-scaled biped
robot with liquid cooled viscoelastic actuators (VLCA). Based on the lessons
learned from previous work from our team on VLCA [1], we present a new system
design embodying a Reaction Force Sensing Series Elastic Actuator (RFSEA) and a
Force Sensing Series Elastic Actuator (FSEA). These designs are aimed at
reducing the size and weight of the robot's actuation system while inheriting
the advantages of our designs such as energy efficiency, torque density, impact
resistance and position/force controllability. The system design takes into
consideration human-inspired kinematics and range-of-motion (ROM), while
relying on foot placement to balance. In terms of actuator control, we perform
a stability analysis on a Disturbance Observer (DOB) designed for force
control. We then evaluate various position control algorithms both in the time
and frequency domains for our VLCA actuators. Having the low level baseline
established, we first perform a controller evaluation on the legs using
Operational Space Control (OSC) [2]. Finally, we move on to evaluating the full
bipedal robot by accomplishing unsupported dynamic walking by means of the
algorithms to appear in [3].Comment: 8 pages, 8 figure
Valuing Changes in Forest Biodiversity
The paper offers an innovative approach to valuation of biodiversity. Instead of the prevailing approach of using only one indicator of biodiversity (usually number of species) we provide evidence that it is possible to provide attributes describing complex characteristics of biodiversity based on sound ecological knowledge. We argue that our approach managed to value the multiâlevel changes in the biological diversity, by using the attributes which described structural, species and functional diversity at the same time. Our study shows that it even complex indicators of multiâlevel biodiversity might be successfully communicated to respondents in a comprehensible and meaningful way. The empirical application of the method is provided based on a choice experiment study conducted in BiaĆowieĆŒa Forest, Poland. The results underline the importance to use multilevel indicators and question validity of only speciesâlevel indicators. Interestingly, the respondents appreciated passive protection regimes, resulting in preservation of natural ecological processes. In addition, the respondents seemed to be concerned by means, and not only the results of protection programmes. Finally, some conclusions for future applications and policy making are drawn
Soluble receptor for advanced glycation end products (sRAGE) as a biomarker of COPD
BACKGROUND: Soluble receptor for advanced glycation end products (sRAGE) is a proposed emphysema and airflow obstruction biomarker; however, previous publications have shown inconsistent associations and only one study has investigate the association between sRAGE and emphysema. No cohorts have examined the association between sRAGE and progressive decline of lung function. There have also been no evaluation of assay compatibility, receiver operating characteristics, and little examination of the effect of genetic variability in non-white population. This manuscript addresses these deficiencies and introduces novel data from Pittsburgh COPD SCCOR and as well as novel work on airflow obstruction. A meta-analysis is used to quantify sRAGE associations with clinical phenotypes. METHODS: sRAGE was measured in four independent longitudinal cohorts on different analytic assays: COPDGene (nâ=â1443); SPIROMICS (nâ=â1623); ECLIPSE (nâ=â2349); Pittsburgh COPD SCCOR (nâ=â399). We constructed adjusted linear mixed models to determine associations of sRAGE with baseline and follow up forced expiratory volume at one second (FEV1) and emphysema by quantitative high-resolution CT lung density at the 15th percentile (adjusted for total lung capacity). RESULTS: Lower plasma or serum sRAGE values were associated with a COPD diagnosis (Pâ<â0.001), reduced FEV1 (Pâ<â0.001), and emphysema severity (Pâ<â0.001). In an inverse-variance weighted meta-analysis, one SD lower log10-transformed sRAGE was associated with 105â±â22 mL lower FEV1 and 4.14â±â0.55 g/L lower adjusted lung density. After adjusting for covariates, lower sRAGE at baseline was associated with greater FEV1 decline and emphysema progression only in the ECLIPSE cohort. Non-Hispanic white subjects carrying the rs2070600 minor allele (A) and non-Hispanic African Americans carrying the rs2071288 minor allele (A) had lower sRAGE measurements compare to those with the major allele, but their emphysema-sRAGE regression slopes were similar. CONCLUSIONS: Lower blood sRAGE is associated with more severe airflow obstruction and emphysema, but associations with progression are inconsistent in the cohorts analyzed. In these cohorts, genotype influenced sRAGE measurements and strengthened variance modelling. Thus, genotype should be included in sRAGE evaluations
A Pragmatic Idealism
A discussion on where do we go from here and why... Interviews with homesteading and agroforestry experts, an organic vegetable farmer, and a cornell student1_4bwzi4f
PICO: Probe of Inflation and Cosmic Origins
The Probe of Inflation and Cosmic Origins (PICO) is a proposed probe-scale space mission consisting of an imaging polarimeter operating in frequency bands between 20 and 800 GHz. We describe the science achievable by PICO, which has sensitivity equivalent to more than 3300 Planck missions, the technical implementation, the schedule and cost
PICO: Probe of Inflation and Cosmic Origins
The Probe of Inflation and Cosmic Origins (PICO) is an imaging polarimeter that will scan the sky for 5 years in 21 frequency bands spread between 21 and 799 GHz. It will produce full-sky surveys of intensity and polarization with a final combined-map noise level of 0.87 K arcmin for the required specifications, equivalent to 3300 Planck missions, and with our current best-estimate would have a noise level of 0.61 K arcmin (6400 Planck missions). PICO will either determine the energy scale of inflation by detecting the tensor to scalar ratio at a level , or will rule out with more than all inflation models for which the characteristic scale in the potential is the Planck scale. With LSST's data it could rule out all models of slow-roll inflation. PICO will detect the sum of neutrino masses at , constrain the effective number of light particle species with , and elucidate processes affecting the evolution of cosmic structures by measuring the optical depth to reionization with errors limited by cosmic variance and by constraining the evolution of the amplitude of linear fluctuations with sub-percent accuracy. Cross-correlating PICO's map of the thermal Sunyaev-Zeldovich effect with LSST's gold sample of galaxies will precisely trace the evolution of thermal pressure with . PICO's maps of the Milky Way will be used to determine the make up of galactic dust and the role of magnetic fields in star formation efficiency. With 21 full sky legacy maps in intensity and polarization, which cannot be obtained in any other way, the mission will enrich many areas of astrophysics. PICO is the only single-platform instrument with the combination of sensitivity, angular resolution, frequency bands, and control of systematic effects that can deliver this compelling, timely, and broad science
PICO: Probe of Inflation and Cosmic Origins
The Probe of Inflation and Cosmic Origins (PICO) is an imaging polarimeter that will scan the sky for 5 years in 21 frequency bands spread between 21 and 799 GHz. It will produce full-sky surveys of intensity and polarization with a final combined-map noise level of 0.87 K arcmin for the required specifications, equivalent to 3300 Planck missions, and with our current best-estimate would have a noise level of 0.61 K arcmin (6400 Planck missions). PICO will either determine the energy scale of inflation by detecting the tensor to scalar ratio at a level , or will rule out with more than all inflation models for which the characteristic scale in the potential is the Planck scale. With LSST's data it could rule out all models of slow-roll inflation. PICO will detect the sum of neutrino masses at , constrain the effective number of light particle species with , and elucidate processes affecting the evolution of cosmic structures by measuring the optical depth to reionization with errors limited by cosmic variance and by constraining the evolution of the amplitude of linear fluctuations with sub-percent accuracy. Cross-correlating PICO's map of the thermal Sunyaev-Zeldovich effect with LSST's gold sample of galaxies will precisely trace the evolution of thermal pressure with . PICO's maps of the Milky Way will be used to determine the make up of galactic dust and the role of magnetic fields in star formation efficiency. With 21 full sky legacy maps in intensity and polarization, which cannot be obtained in any other way, the mission will enrich many areas of astrophysics. PICO is the only single-platform instrument with the combination of sensitivity, angular resolution, frequency bands, and control of systematic effects that can deliver this compelling, timely, and broad science