4,768 research outputs found
Influence of Road Connectivity and Public Transport Accessibility on Subjective Wellbeing during Travel: An Explanation from Travel Mode: Evidence from five Communities around Subway Stations in Harbin
Existing studies have shown that increased subjective wellbeing comes with individual and societal benefits. Now citizens spend a significant amount of time per day on trips. Whether the change of transport environment factors, especially the construction of subway station can effectively improve residents' subjective wellbeing during travel or not is now concerned more than before when creating a “Real Emotional City”. This study aims to explore the relationship between road connectivity, public transport accessibility around subway stations and residents' subjective wellbeing during travel, and the mediating effect of travel modes. Data form 400 residents were collected from communities in Harbin which included travel modes, subjective wellbeing during travel and basic individual information. It turns out that the cognitive judgments and the emotional feelings (two aspects of travel wellbeing) need to be discussed separately because they are almost independently affected. Although cycling and walking are active, only pedestrians reported higher travel satisfaction when controlling travel time and other confounding factors. We found that for each additional unit of road network density, the number of people travelling by public transport will increase. Residents with better bus station accessibility and who have better road connectivity are likely to have higher travel satisfaction. Pleasant travel mood is not related to bus accessibility, and had a weak relationship with distance to subway station. In addition, residents closer to subway stations have higher levels of satisfaction and positive mood, but the results of subway travelers prove that this does not come from their cognitive judgments during travel, which indicates that some other factors may be more important. The findings highlight the heterogeneity of relationships between travel mode, transport environment factors and subjective wellbeing and have implications for intervention strategies and policies designed to promote travel environmental and behaviour chang
SVD-based Method for Radio Frequency Interference Suppression Applied to SAR
Synthetic aperture radar (SAR) is a special type of active microwave sensor, which has got a wide range of applications in remote sensing. However, the performance of SAR systems may be affected by radio frequency interference (RFI) in several geographic regions. A novel singular value decomposition method is proposed for radio frequency interference suppression applied to SAR. This method decomposes the singular vectors of the received signal with RFI into interference subspace and signal subspace. The orthogonality of the two subspaces is used to suppress the RFI. The point-target simulation is used to show the working principle of the proposed algorithm. The experimental results based on SAR real data are also shown to verify the proposed algorithm.Defence Science Journal, 2012, 62(2), pp.132-136, DOI:http://dx.doi.org/10.14429/dsj.62.114
Amplitude and Phase Statistics of Multi-look SAR Complex Interferogram
Amplitude and phase statistics of SAR complex interferogram are significant in the study of interferometry and polarimetry. To reduce statistical variations, multi-look processing is adopted by averaging spatially the complex interferogram. In this study, we derive and validate three kinds of probability density functions (PDFs) of multi-look interferogram for different surface feature scenes. For simple homogeneous areas with the gamma distribution intensity, a concise product-form interferometry phase PDF is derived, which is equivalent to a conventional Gauss hypergeometric PDF. For complicated areas with the K and G0 distributions intensity, two new interferometry amplitude PDFs named as Gamma-K and Gamma-G are proposed, and their phase PDFs are approximately preserved. Finally three typical areas including grass, mountain, and city are picked out from a pair of RADARSAT-2 SAR images and studied. Experimental results indicate good agreement between the computed histograms and the theoretical distributions. The results obtained can be applied to the feature classification of polarisation SAR data and the estimation of decorrelation effect of interferometric SAR.Science Journal, Vol. 64, No. 6, November 2014, pp.564-570, DOI:http://dx.doi.org/10.14429/dsj.64.474
State-independent quantum contextuality with projectors of nonunit rank
Virtually all of the analysis of quantum contextuality is restricted to the
case where events are represented by rank-one projectors. This restriction is
arbitrary and not motivated by physical considerations. We show here that
loosening the rank constraint opens a new realm of quantum contextuality and we
demonstrate that state-independent contextuality can even require projectors of
nonunit rank. This enables the possibility of state-independent contextuality
with less than 13 projectors, which is the established minimum for the case of
rank one. We prove that for any rank, at least 9 projectors are required.
Furthermore, in an exhaustive numerical search we find that 13 projectors are
also minimal for the cases where all projectors are uniformly of rank two or
uniformly of rank three.Comment: 9+9 pages, 4 figures. Published versio
Standard metabolic rate predicts growth trajectory of juvenile Chinese crucian carp (Carassius auratus) under changing food availability
Phenotypic traits vary greatly within populations and can have a significant influence on aspects of performance. The present study aimed to investigate the effects of individual variation in standard metabolic rate (SMR) on growth rate and tolerance to food-deprivation in juvenile crucian carp (Carassius auratus) under varying levels of food availability. To address this issue, 19 high and 16 low SMR (individuals were randomly assigned to a satiation diet for 3 weeks, whereas another 20 high and 16 low SMR individuals were assigned to a restricted diet (approximately 50% of satiation) for the same period. Then, all fish were completely food-deprived for another 3 weeks. High SMR individuals showed a higher growth rate when fed to satiation, but this advantage of SMR did not exist in food-restricted fish. This result was related to improved feeding efficiency with decreased food intake in low SMR individuals, due to their low food processing capacity and maintenance costs. High SMR individuals experienced more mass loss during food-deprivation as compared to low SMR individuals. Our results here illustrate context-dependent costs and benefits of intraspecific variation in SMR whereby high SMR individuals show increased growth performance under high food availability but had a cost under stressful environments (i.e., food shortage)
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