7,888 research outputs found

    Reimagining career guidance: towards a pluralistic perspective

    Get PDF
    Difficulties concerning the identified mis-match between supply and demand sides of the labour market are discussed. The variability of career guidance services for young people across Europe is illustrated together with policy initiatives in some cases leading to problems of professional identity and limited support to clients of the service. The risks associated with a monoculture of ‘one size fits all’ approach to guidance practice are discussed. The principles of pluralistic approaches to counselling are discussed with the suggestion that this might prove to be a fertile way forward for career guidance practice

    Influence of human body on massive MIMO indoor channels

    Full text link
    © 2019 IEEE. Massive MIMO can dramatically improve capacity and spectral efficiency. However, it is not very clear whether it can significantly improve the signal blockage problem that exists in single antenna systems. In this paper, we investigate the impact of the human body on indoor massive MIMO channels, using practically measured channel data for a 32x8 massive MIMO system in a complex office environment. We introduce a parameter of Power Imbalance (PI) indices to estimate the wide-sense none-stationarity in multiple domains and another parameter of Channel Popularity Indices (CPI) to predict the popularity of MIMO channel. We find that in most cases, the presence of the human body still has a non- negligible negative impact. It decreases the ergodic capacity by about 8% and increases the path loss exponent by 1. In average, the ergodic capacity for NLOS channels are 15% higher than that for LOS

    Modeling the stress dependence of magnetic hysteresis based on Stoner-Wohlfarth theory

    Full text link
    © 2015 IEEE. This paper presents an improved approach for simulating magnetic hysteresis, which takes into account the effect of applied stress, based on an extended Stoner-Wohlfarth (S-W) model. Meanwhile, the S-W asteroid rotates and shrinks, and the stable direction of magnetization of the particle can be calculated from the new energy minimum conditions. This developed model is applied to analyze the magnetic hysteresis phenomenon of a soft magnetic composite (SMC) material under different compaction process, and the results of simulations are in good quantitative agreement with experimental data

    Measurement and Modeling of Wireless Off-Body Propagation Characteristics under Hospital Environment at 6-8.5 GHz

    Full text link
    © 2013 IEEE. A measurement-based novel statistical path-loss model with a height-dependent factor and a body obstruction (BO) attenuation factor for off-body channel under a hospital environment at 6-8.5 GHz is proposed. The height-dependent factor is introduced to emulate different access point (AP) arrangement scenarios, and the BO factor is employed to describe the effect caused by different body-worn positions. The height-dependent path-loss exponent is validated to fluctuate from 2 to 4 with AP height increasing by employing both computer simulation and classical two-ray model theory. As further validated, the proposed model can provide more flexibility and higher accuracy compared with its existing counterparts. The presented channel model is expected to provide wireless link budget estimation and to further develop the physical layer algorithms for body-centric communication systems under hospital environments

    Two-dimensional elemental operator for modeling the vectorial hysteresis of soft magnetic composite material

    Full text link
    © 2015 IEEE. This paper presents a two-dimensional elemental operator with biaxial anisotropy based on the physical mechanisms of the cubic textured magnetic materials, and deduces an analytical expression of the direct relationship between magnetic field strength H and magnetization M for a single elemental operator by the partial approximate substitutions. To verify the proposed model, the magnetic hysteresis of a soft magnetic composite material SOMALOYTM 500 under alternating excitations was simulated and compared with the experimental results obtained by a 3D magnetic property tester. The results suggest that the proposed approach can be a useful tool in the modeling of vectorial magnetic hysteresis and the calculation of iron loss in practical engineering electromagnetic field analysis

    Improving Representation of Deforestation Effects on Evapotranspiration in the E3SM Land Model

    Get PDF
    Evapotranspiration (ET) plays an important role in land-atmosphere coupling of energy, water, and carbon cycles. Following deforestation, ET is typically observed to decrease substantially as a consequence of decreases in leaf area and roots and increases in runoff. Changes in ET (latent heat flux) revise the surface energy and water budgets, which further affects large-scale atmospheric dynamics and feeds back positively or negatively to long-term forest sustainability. In this study, we used observations from a recent synthesis of 29 pairs of adjacent intact and deforested FLUXNET sites to improve model parameterization of stomatal characteristics, photosynthesis, and soil water dynamics in version 1 of the Energy Exascale Earth System Model (E3SM) Land Model (ELMv1). We found that default ELMv1 predicts an increase in ET after deforestation, likely leading to incorrect estimates of the effects of deforestation on land-atmosphere coupling. The calibrated model accurately represented the FLUXNET observed deforestation effects on ET. Importantly, the search for global optimal parameters converged at values consistent with recent observational syntheses, confirming the reliability of the calibrated physical parameters. Applying this improved model parameterization to the globe scale reduced the bias of annual ET simulation by up to ~600 mm/year. Analysis on the roles of parameters suggested that future model development to improve ET simulation should focus on stomatal resistance and soil water-related parameterizations. Finally, our predicted differences in seasonal ET changes from deforestation are large enough to substantially affect land-atmosphere coupling and should be considered in such studies

    Two maternal origins of Chinese domestic light-body type goose

    Get PDF
    China is particularly rich in goose genetic resources. The systemic study of genetic diversity and origin of Chinese indigenous geese will provide important scientific basis for the conservation, utilization of resources and human history. The 521 bp control region (D-loop) of mitochondrial DNA from 13 lightbody type breeds was sequenced. The results showed that in the D-loop region of the 13 gray goose breeds, the content of T, C, A and G nucleotides was 23.8, 29.0, 32.2 and 15.1%, respectively. The average haplotype diversity (Hd) and nucleotide diversity (Pi) of domestic geese were 0.2153 and 0.00046, respectively. The 13 light-body type breeds had bigger nucleotide variance value among populations than the value within populations and all the breeds did not exist population expansion.Shared haplotype analysis and systemic systematic evolution analysis revealed that Chinese lightbody type domestic goose owned two maternal origins. YL goose breed originated from greylag goose (anser anser), and the other 12 light- body type goose breeds originated from swan goose (anser cygnoides)

    Photo-induced enhanced Raman spectroscopy (PIERS): Sensing atomic-defects, explosives and biomolecules

    Get PDF
    Enhanced Raman relies heavily on finding ideal hot-spot regions which enable significant enhancement factors. In addition, the termed “chemical enhancement” aspect of SERS is often neglected due to its relatively low enhancement factors, in comparison to those of electromagnetic (EM) nature. Using a metal-semiconductor hybrid system, with the addition of induced surface oxygen vacancy defects, both EM and chemical enhancement pathways can be utilized on cheap reusable surfaces. Two metal-oxide semiconductor thin films, WO3 and TiO2, were used as a platform for investigating size dependent effects of Au nanoparticles (NPs) for SERS (surface enhanced Raman spectroscopy) and PIERS (photo-induced enhanced Raman spectroscopy – UV pre-irradiation for additional chemical enhancement) detection applications. A set concentration of spherical Au NPs (5, 50, 100 and 150 nm in diameter) was drop-cast on preirradiated metal-oxide substrates. Using 4-mercaptobenzoic acid (MBA) as a Raman reporter molecule, a significant dependence on the size of nanoparticle was found. The greatest surface coverage and ideal distribution of AuNPs was found for the 50 nm particles during SERS tests, resulting in a high probability of finding an ideal hot-spot region. However, more significantly a strong dependence on nanoparticle size was also found for PIERS measurements – completely independent of AuNP distribution and orientation affects – where 50 nm particles were also found to generate the largest PIERS enhancement. The position of the analyte molecule with respect to the metal-semiconductor interface and position of generated oxygen vacancies within the hot-spot regions was presented as an explanation for this result

    A wearable loop-dipole combined antenna

    Get PDF
    The design approach of a loop-dipole combined antenna for wearable applications is proposed. In order to mitigate the antenna’s performance deterioration caused by the human body, additional loops are incorporated with a wideband dipole. The loops can i) widen the impedance bandwidth by minimizing the reactance of the antenna, ii) increase the antenna’s directivity and iii) act as wearable accessories for easy mounting to the users’ bodies as well. Then, the interaction between the antenna and the human body can be reduced. The antenna is simulated and measured for both free space and on-body cases. Operation bandwidth of 40% (20log|S11| < -10 dB) from 6 to 9 GHz is obtained. The measured results show good agreement with the simulated ones
    corecore