377 research outputs found
Time out of work and skill depreciation
This paper investigates the role of skill depreciation in the relationship between work interruptions and subsequent wages. Using unique longitudinal microdata containing information on the ability to understand and practically employ printed information, we are able to analyze changes in skills for individuals as a function of time out of work. In general, we find statistically strong evidence of a negative relationship between work interruptions and skills. Our analysis suggests that depreciation of general information-processing skills is economically significant, with a full year of non-employment being equivalent to moving 5 percentiles down the skill distribution.Work interruptions; skill depreciation; wage differentials
Time Out of Work and Skill Depreciation
This paper investigates the role of skill depreciation in the relationship between work interruptions and subsequent wages. Using a unique longitudinal dataset, the Swedish part of the International Adult Literacy Survey, we are able to analyze changes in literacy skills for individuals as a function of time out of work. In general, we find statistically strong evidence on a negative relationship between work interruptions and skills. Our analysis suggests that depreciation of general (literacy) skills is economically significant. Our estimates imply that a full year of non-employment is associated with skill losses that are equivalent to moving 5 percentiles down the skill distribution.Work interruptions; Skill depreciation; Unemployment; Wage differentials
Retrieval of forest stem volume using VHF SAR
The ability to retrieve forest stem volume using CARABAS (coherent all radio band sensing) SAR images (28â60 MHz) has been investigated. The test site is a deciduous mixed forest on the island of Ăland in southern Sweden. The images have been radiometrically calibrated using an array of horizontal dipoles. The images exhibit a clear discrimination between the forest and open fields. The results show that the dynamic range of the backscattering coefficient among the forest stands is higher than what has been found with conventional SAR using microwave frequencies. The backscatter increases with increasing radar frequency. This work shows an advantage compared to higher frequencies for stem volume estimation in dense forests
Simultaneous channel and symbol maximum likelihood estimation in Laplacian noise
This paper treats channel estimation and signal detection in Laplacian noise. The received signal is assumed to be a transmitted signal which has been corrupted by an unknown channel, modeled as a FIR filter, the output being further disturbed by additive independent Laplacian noise. The transmitted signal is assumed to depend on an unknown parameter belonging to a known finite set. The simultaneous maximum likelihood (ML) estimator of the unknown parameter, as well as of the FIR filter coefficients, is derived. The ML estimate of the channel can be obtained by using a linear programming approach and the decision about the parameter is based on the output from a set of generalized matched filters. Simulation results are included in order to illustrate the performance of the proposed receiver
148. Carbon Nanotubes
Carbon nanotubes (CNTs) can be seen as graphene sheets rolled to form cylinders. CNTs may be categorised as single- (SWCNT) or multi-walled (MWCNT). Due to the small size, the number of particles as well as the surface area per mass unit is extremely high. CNTs are highly diverse, differing with respect to e.g., diameter, length, chiral angles, chemical functionalisation, purity, stiffness and bulk density. Today, CNTs are utilised primarily for the reinforcement of composite polymers, but there is considerable potential for other applications. The rapidly growing production and use of CNTs increases the risk for occupational exposure. Since CNTs in bulk form are of very low density and much dust is produced during their handling, exposure by inhalation appears to represent the greatest potential risk in the work place. However, most work place measurements involved sampling periods that are too short, varying sampling techniques and non-specific analytical methods. CNTs may be absorbed via inhalation and ingestion. Systemic uptake via the skin has not been demonstrated. Human toxicity data on CNTs are lacking and interpretation of animal studies is often problematic since the physical properties and chemical composition are diverse, impurities may be present and data are sometimes omitted. Because of the physical similarities between asbestos and CNTs, it can be suspected that the latter may also cause lung fibrosis, mesothelioma and lung cancer following inhalation. Intraperitoneal and intrascrotal administration of CNTs causes mesothelioma in animals, but no inhalation carcinogenicity studies have been conducted. Thus, it is too early conclude whether CNTs cause mesothelioma and lung cancer in humans. Both SWCNTs and MWCNTs cause inflammation and fibrosis in the lungs of relevant animal types and for MWCNTs these effects are also seen in the pleura. For instance, minimal histiocytosis and mild granulomatous inflammation in the lungs and lung-draining lymph nodes have been observed in rats exposed for 13 weeks to 0.1 mg/m3 MWCNTs (lowest observed adverse effect level, LOAEL), with more pronounced inflammation in both mice and rats at higher doses. Thus, inflammatory responses in the lungs may be considered as the critical effect. However, the LOAEL of CNTs should be interpreted cautiously, since their toxicity is likely to vary widely, depending on the structure and physicochemical properties, as well as the contribution from non-carbon components. It is also uncertain which dose metric (e.g., mass, number or surface area per air volume unit) is most appropriate. Some studies indicate that longer straight CNTs evoke more pronounced biological effects than shorter or tangled fibres
Design and Development of an Architecture for Demonstrating the Interplay of Emerging SISO Standards
Simulation Interoperability Standards Organization (SISO) SIW Conference PaperThe Simulation Interoperability Standards Organization (SISO) focuses on facilitating simulation
interoperability across government and non-government applications worldwide. A number of standards are
emerging that will individually have great impact on the development and operation of simulation systems, as well
as interoperation across simulation systems and command and control systems. Taken together, however, the
emerging standards represent a set of capabilities and technologies which can revolutionize the simulation industry,
radically improving the way we develop and deliver interoperable systems
On the Impact of Hardware Impairments on Massive MIMO
Massive multi-user (MU) multiple-input multiple-output (MIMO) systems are one
possible key technology for next generation wireless communication systems.
Claims have been made that massive MU-MIMO will increase both the radiated
energy efficiency as well as the sum-rate capacity by orders of magnitude,
because of the high transmit directivity. However, due to the very large number
of transceivers needed at each base-station (BS), a successful implementation
of massive MU-MIMO will be contingent on of the availability of very cheap,
compact and power-efficient radio and digital-processing hardware. This may in
turn impair the quality of the modulated radio frequency (RF) signal due to an
increased amount of power-amplifier distortion, phase-noise, and quantization
noise.
In this paper, we examine the effects of hardware impairments on a massive
MU-MIMO single-cell system by means of theory and simulation. The simulations
are performed using simplified, well-established statistical hardware
impairment models as well as more sophisticated and realistic models based upon
measurements and electromagnetic antenna array simulations.Comment: 7 pages, 9 figures, Accepted for presentation at Globe-Com workshop
on Massive MIM
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