Search results for "passive"
showing 10 items of 375 documents
Remote optical monitoring in remotely power assisted passive optical networks
2010
In this paper, the authors present the latest results on a simple and low cost method to achieve a dynamic and flexible network monitoring. By placing several fiber Bragg gratings (FBG) along the passive optical gigabit Ethernet infrastructure (GePON), the proposed modified optical time domain reflectometer (OTDR) is able to monitor the entire system by simply tuning its working wavelength. Furthermore, the optical network terminals (ONT), at the end users premises, have been interconnected to the trunk via an innovative cable able to both carry the optical signal as well as the power supply.
Three-dimensional architecture of the whole human soleus muscle in vivo
2018
Background Most data on the architecture of the human soleus muscle have been obtained from cadaveric dissection or two-dimensional ultrasound imaging. We present the first comprehensive, quantitative study on the three-dimensional anatomy of the human soleus muscle in vivo using diffusion tensor imaging (DTI) techniques. Methods We report three-dimensional fascicle lengths, pennation angles, fascicle curvatures, physiological cross-sectional areas and volumes in four compartments of the soleus at ankle joint angles of 69 ± 12° (plantarflexion, short muscle length; average ± SD across subjects) and 108 ± 7° (dorsiflexion, long muscle length) of six healthy young adults. Microdissection and…
The SMAP and Copernicus Sentinel 1A/B microwave active-passive high resolution surface soil moisture product
2019
Abstract Soil Moisture Active Passive (SMAP) mission of NASA was launched in January 2015. Currently, SMAP has an L-band radiometer and a defunct L-band radar with a rotating 6-m mesh reflector antenna. On July 7th, 2015, the SMAP radar malfunctioned and became inoperable. Consequently, the production of high-resolution active-passive soil moisture product got hampered, and only ~2.5 months (April 15th, 2015 to July 7th, 2015) of data remain available. Therefore, during the SMAP post-radar phase, many ways were examined to restart the high-resolution soil moisture product generation of the SMAP mission. One of the feasible approaches was to substitute the SMAP radar with other available SAR…
The SMAP mission combined active-passive soil moisture product at 9 km and 3 km spatial resolutions
2018
Abstract The NASA Soil Moisture Active Passive (SMAP) mission was launched on January 31st, 2015. The spacecraft was to provide high-resolution (3 km and 9 km) global soil moisture estimates at regular intervals by combining for the first time L-band radiometer and radar observations. On July 7th, 2015, a component of the SMAP radar failed and the radar ceased operation. However, before this occurred the mission was able to collect and process ~2.5 months of the SMAP high-resolution active-passive soil moisture data (L2SMAP) that coincided with the Northern Hemisphere's vegetation green-up and crop growth season. In this study, we evaluate the SMAP high-resolution soil moisture product deri…
PERMANENT INCOME, CONVERGENCE AND INEQUALITY AMONG COUNTRIES
2008
The literature on inequality has generally focused on the analysis of annual per capita income. This paper adopts a different approach by considering the life-cycle dimension of inequality and convergence between economies from 1960 to 2000. We analyze the present value of the set of incomes individuals obtain throughout their whole life (permanent income). On the basis of this approach, various simulations are made to determine the effect on inequality in permanent income of variables such as survival rates and the long-run growth rates in current income. The results indicate that survival rates are an important source of inequality. Inequality in permanent income is about one third higher…
Spectral Slicing of a Supercontinuum Source for WDM/DS-OCDMA Application
2008
WDM and optical CDMA are leading contenders to easily upgrade access network performances in terms of multiple access technique. Both methods can be used at once, using a single multiwavelength optical source. We show, numerically and experimentally, that spectral slicing of a 10-GHz pulse train broadened to a supercontinuum yields pulses suitable for use in a direct sequence optical CDMA system. Simulations with optical CDMA encoders and decoders based on superstructured fiber Bragg gratings indicate good performance can be expected.
Earthquake Excited Base-Isolated Structures Protected by Tuned Liquid Column Dampers: Design Approach and Experimental Verification
2017
Abstract In this contribution a direct approach for optimal design of a Tuned Liquid Column Damper (TLCD) device attached to the base slab of a base-isolated structure is presented, aiming at reducing the seismic displacement demand of the base-isolation subsystem. Assuming white noise base excitation, for a wide parameter range a direct optimization procedure yields design charts for optimal TLCD quantities. The performance of the base-isolated structure equipped with optimally tuned TLCD device in comparison to the simple base-isolated one is evaluated both numerically and experimentally. In a numerical study the system is subjected to the 44 records of the FEMA P-695 far-field ground mot…
Hybrid Passive Control Strategies for Reducing the Displacements at the Base of Seismic Isolated Structures
2019
In this paper, the use of hybrid passive control strategies to mitigate the seismic response of a base-isolated structure is examined. The control performance of three different types of devices used for reducing base displacements of isolated buildings is investigated. Specifically, the Tuned Mass Damper (TMD), the New Tuned Mass Damper (New TMD) and the Tuned Liquid Column Damper (TLCD), each one associated to a Base Isolated structure (BI), have been considered. The seismic induced vibration control of base-isolated structures equipped with the TMD, New TMD or the TLCD is examined and compared with that of the base-isolated system without devices, using real recorded seismic signals as e…
Modelling and optimization of a passive structural control design for a spar-type floating wind turbine
2014
Abstract Compared with fixed-bottom installation, deep water floating wind turbine has to undergo more severe structural loads due to extra degrees of freedom. Aiming for effective load reduction, this paper deals with the evaluation of a passive structural control design for a spar-type floating wind turbine, and the proposed strategy is to install a tuned mass damper (TMD) into the spar platform. Firstly, a mathematical model for wind turbine surge-heave-pitch motion is established based on the D’Alembert’s principle of inertial forces. Then, parameter estimation is performed by comparing the outputs from the proposed model and the state-of-the-art simulator. Further, different optimizati…