687 research outputs found
A global adaptive learning control for robotic manipulators
No full textThis paper addresses the problem of designing a global adaptive learning control for robotic manipulators with revolute joints and unknown dynamics. The reference signals to be tracked are assumed to be smooth and periodic with known period. By developing in Fourier series expansion the
input reference signals of every joint, an adaptive learning PD control is designed which ’learns’ the input reference signals by
identifying their Fourier coefficients: global asymptotic tracking and local exponential tracking of both the input and the output reference signals is obtained when the Fourier series expansion of each input reference signal is finite, while arbitrary small tracking errors are achieved otherwise. The resulting control is not model based and depends only on the period of the reference signals and on some constant bounds on the robot dynamics
Global adaptive learning control of robotic manipulators by output error feedback
No full textThis paper addresses the problem of designing a global, output error feedback based, adaptive learning control for robotic manipulators with revolute joints and uncertain dynamics. The reference signals to be tracked are assumed to be smooth and periodic with known period. By developing in Fourier series expansion the input reference signals of every joint, an adaptive, output error feedback, learning control is designed which 'learns' the input reference signals by identifying their Fourier coefficients: global asymptotic and local exponential stability of the tracking error dynamics are obtained when the Fourier series expansion of each Input reference signal is finite, while arbitrary small tracking errors are achieved otherwise. The resulting control is not model based and depends only on the period of the reference signals and on some constant bounds on the robot dynamics. © 2006 IEEE
Etna CO2 Soil Flux during 2002-2010 (ECSF2002_2010)
No full textThe ETNAGAS network comprises 19 monitoring stations distributed across the flanks of Mount Etna, specifically designed for the continuous observation of soil-emitted carbon dioxide (CO₂). Each station is equipped with infrared (IR) sensors for the precise measurement of CO₂ concentrations, along with meteorological sensors that record key environmental parameters including air temperature, atmospheric pressure, wind speed and direction, and precipitation. These data enable the estimation of CO₂ soil fluxes through the application of the method proposed by Gurrieri and Valenza (1988) (see Methods for details). The ETNAGAS network represents a high-resolution geochemical surveillance system and constitutes an integral component of the national framework for monitoring volcanic gas emissions. Its primary objective is to contribute to the assessment of the volcanic activity state of Mount Etna through systematic and spatially distributed measurements of gaseous emissions.The monitoring stations of the ETNAGAS network were entirely developed by the Istituto Nazionale di Geofisica e Vulcanologia (INGV), Palermo section. These stations are capable of continuously measuring several environmental and geochemical parameters, including soil CO₂ concentration, atmospheric temperature, pressure, relative humidity, rainfall, wind speed, and wind direction. Data are acquired at hourly intervals and automatically transmitted to the monitoring center at INGV-Palermo. It should be noted that not all stations are equipped with the full suite of meteorological sensors.
CO₂ fluxes from the soil can be derived from the recorded data using the dynamic (or dilution) method described by Gurrieri and Valenza (1988). This method is based on measuring the CO₂ content in a mixture of soil gas and atmospheric air (Cd), obtained using a probe inserted approximately 50 cm into the ground. Soil gases enter the probe through its base and are mixed with ambient air; this mixture is then pumped into an infrared (IR) spectrophotometer, which measures the CO₂ concentration.
According to Gurrieri and Valenza, the measured diluted concentration (Cd) is empirically related to the actual soil CO₂ flux (ϕCO₂) through a relationship established under laboratory conditions, across a range of gas permeabilities (0.36–123 mm²) and pumping flow rates (0.4–4.0 L/min) [Camarda et al., 2006a, 2006b].
REFERENCE
• Camarda, M., S. Gurrieri, and M. Valenza (2006a), CO2 flux measurements in volcanic areas using the dynamic concentration method: Influence of soil permeability, J. Geophys. Res., 111, B05202, doi:10.1029/2005JB003898. Camarda, M., S. Gurrieri, and M. Valenza (2006b), In situ permeability measurements based on a radial gas advection model: Relationships between soil permeability and diffuse CO2 degassing in volcanic areas, Pure Appl. Geophys., 163(4), 897–914, doi:10.1007/s00024-006-0045-y.
• Gurrieri, S., and M. Valenza (1988), Gas transport in natural porous mediums: A method for measuring CO2 flows from the ground in volcanic and geothermal areas, Rend. Soc. Ital. Mineral. Petrol., 43, 1151–1158.
• Gurrieri, S., M. Liuzzo, and G. Giudice, (2008), Continuous monitoring of soil CO2 flux on Mt. Etna: The 2004–2005 eruption and the role of regional tectonics and volcano tectonics, J. Geophys. Res., 113, B09206, doi:10.1029/2007JB005003, 2008.
• Liuzzo M., Gurrieri S., Giudice G. & Giuffrida G. (2013) - Ten years of soil CO2 continuous monitoring on Mt. Etna: Exploring the relationship between processes of soil degassing and volcanic activity. Geochem. Geophys. Geosyst., 14, 2886-2899. https://doi. org/10.1002/ggge.2019
The components of microbiological risk analysis
No full textThe paper describes the process of risk analysis in a food safety perspective. The steps of risk analysis defined as a process consisting of three interconnected components (risk assessment, risk management, and risk communication) are analysed. The different components of the risk assessment, risk management and risk communication are further described
Global adaptive learning control of robotic manipulators by output error feedback
No full textThis paper addresses the problem of designing a global, output error feedback based, adaptive learning control for robotic manipulators with revolute joints and uncertain dynamics. The reference signals to be tracked are assumed to be smooth and periodic with known period. By developing in Fourier series expansion the input reference signals of every joint, an adaptive, output error feedback, learning control is designed, which ‘learns’ the input reference signals by identifying their Fourier coefficients: global asymptotic and local exponential stability of the tracking error dynamics are obtained when the Fourier series expansion of each input reference signal is finite, while arbitrary small tracking errors are achieved otherwise. The resulting control is not model based and depends only on the period of the reference signals and on some constant bounds on the robot dynamics
A global adaptive learning control for robotic manipulators
No full textThis paper addresses the problem of designing a global adaptive learning control for robotic manipulators with revolute joints and uncertain dynamics. The reference signals to be tracked are assumed to be smooth and periodic with known period. By developing in Fourier series expansion the input reference signals of every joint, an adaptive learning PD control is designed which ‘learns’ the input reference signals by identifying their Fourier coefficients: global asymptotic and local exponential stability of the tracking error dynamics are obtained when the Fourier series expansion of each input reference signal is finite, while arbitrary small tracking errors are achieved otherwise. The resulting control is not model based and depends only on the period of the reference signals and on some constant bounds on the robot dynamics
Civil Rights Heritage Tour: Viola Liuzzo Memorial, circa 1994
No full textEvelyn G. Lowery and Johnnie Carr are shown standing beside the Viola Liuzzo memorial monument.The Atlanta University Center Robert W. Woodruff Library acknowledges the generous support of the Joseph & Evelyn Lowery Institute for Justice and Human Rights, the Joseph Echols Lowery Irrevocable Trust, and other donors in supporting the processing and digitization of Morehouse College's Joseph Echols and Evelyn Gibson Lowery Collection
Civil Rights Heritage Tour: Vandalized Viola Liuzzo Memorial, circa 1997
No full textEvelyn G. Lowery speaks next to the Viola Liuzzo memorial monument, which is vandalized with the painting of a Confederate flag. Dr. Gwendolyn M. Patton stands at left in the photo.The Atlanta University Center Robert W. Woodruff Library acknowledges the generous support of the Joseph & Evelyn Lowery Institute for Justice and Human Rights, the Joseph Echols Lowery Irrevocable Trust, and other donors in supporting the processing and digitization of Morehouse College's Joseph Echols and Evelyn Gibson Lowery Collection
Understanding the Accelerating Effect of - Caprolactam on the Formation of Urethane Linkages
No full textThe accelerating role of -caprolactam on the formation of urethane linkages is studied in
the case of the reaction between toluene 2,4-diisocyanate and n-propanol in carbon tetrachloride at room
temperature. FT-IR spectroscopy is exploited to follow the consumption of the isocyanate groups. The
comparison between the rate of the reactions carried out in the presence and absence of a catalytic amount
of -caprolactam shows its accelerating effect. The acylurea-like derivative 1-methyl-2,4-[(2-oxoazepane-
1-carbonyl)amino]benzene has been prepared and identified as the real catalytic species formed in situ
as a result of the reaction between toluene 2,4-diisocyanate and -caprolactam. A kinetic model is proposed
to analyze the experimental data, and B3LYP/6-31+G* calculations are exploited to investigate the
structure of 1-methyl-2,4-[(2-oxoazepane-1-carbonyl)amino]benzene and clarify the structural features
leading the catalytic activity
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