364 research outputs found
A Case Study on Optimization of Building Design Based on CFD Simulation Technology of Wind Environment
AbstractFor green buildings, the building technology needs to fit the climatic characteristics to adjust to the existing conditions and create a more livable environment. CFD is a combination of modern fluid dynamics, numerical mathematics and computer science. It is employed in green building design to offer the architect an important basis for optimizing the architectural design. The Paper takes a case study to show the research on application of CFD simulation technology of wind environment in optimizing architectural design, gives some ideas to architects in green building design optimization
OPTIMAL FLIGHT TRAJECTORY GENERATION ALGORITHMS FOR URBAN AIR MOBILITY
The concept of Urban Air Mobility (UAM) has gained significant attention recently. In this vibrant domain, the capability of generating an optimal flight trajectory is of essential importance. This study aims to provide analytical solutions to generate the optimal trajectory in the three most common UAM scenarios. The first case is the comfort-optimal trajectory for drone package delivery and air taxis carrying passengers. The cost is evaluated as a linear combination of acceleration (or specific support force) and flight time. The second case is the control-effort-optimal trajectory for hovering vehicles. Hovering vehicles are expected to be the dominant model of air taxi. The objective function is a linear combination of thrust and flight time. The third case is the Direct-Operating-Cost (DOC) optimal trajectory for electric fixed-wing aircraft, on which all major aerospace companies are working. DOC is a linear combination of energy consumption and flight time.
The trajectory optimization problems are formulated as optimal control problems and the Pontryagen’s Minimum Principle is applied to solve them. The solution is the reference position as a function of time, which is a guidance law and is fed to the downstream flight controller. The biggest advantage of an analytical solution is to reduce the computational time. It can also be integrated with other flight path planning methods. Several simulation examples will be presented to show the effectiveness of the proposed method
The N\'eel order for a frustrated antiferromagnetic Heisenberg model: beyond linear spin-wave theory
Within Dyson-Maleev (DM) transformation and self-consistent mean-field
treatment, the N\'eel order/disorder transition is studied for an
antiferromagnetic Heisenberg model which is defined on a square lattice with a
nearest neighbour exchange and a next-nearest neighbour exchange
along only one of the diagonals. It is found that the N\'eel order may exist up
to , beyond its classically stable regime. This result
qualitatively improves that from linear spin-wave theory based on
Holstein-Primakoff transformation.Comment: 10 pages, 4 eps figure
Sex differences in white matter development during adolescence: A DTI study
Adolescence is a complex transitional period in human development, composing physical maturation, cognitive and social behavioral changes. The objective of this study is to investigate sex differences in white matter development and the associations between intelligence and white matter microstructure in the adolescent brain using diffusion tensor imaging (DTI) and tract-based spatial statistics (TBSS). In a cohort of 16 typically-developing adolescents aged 13 to 17 years, longitudinal DTI data were recorded from each subject at two time points that were one year apart. We used TBSS to analyze the diffusion indices including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). Our results suggest that boys (13–18 years) continued to demonstrate white matter maturation, whereas girls appeared to reach mature levels earlier. In addition, we identified significant positive correlations between FA and full-scale intelligence quotient (IQ) in the right inferior fronto-occipital fasciculus when both sexes were looked at together. Only girls showed significant positive correlations between FA and verbal IQ in the left cortico-spinal tract and superior longitudinal fasciculus. The preliminary evidence presented in this study supports that boys and girls have different developmental trajectories in white matter microstructure
Evaluation of Head Impact Exposure Between One Season of Youth Versus High School Football
In Volume 4, Issue 1 of the JSMAHS you will find Professional research abstracts, as well as Under Graduate student research abstracts, case reports, and critically appraised topics.
Thank you for viewing this 4th Annual OATA Special Edition
The multidimensional relative poverty of rural older adults in China and the effect of the health poverty alleviation policy
IntroductionAlthough, especially in the past decade, poverty measurement approaches have been duly developed in two paths (from unidimensional to multidimensional poverty and from absolute to relative poverty), merely a few studies have focused on the combination of both perspectives. However, with global aging, poverty among older adults simultaneously presents multidimensionality and relativity characteristics. This paper explores a multidimensional relative poverty index (MRPI) relative to the aged group in four dimensions, namely, health, social, mental, and material, and then empirically evaluates the specific effects on the MRPI of one of the key targeted anti-poverty policies, that is, the health poverty alleviation policy (HPAP), which includes public health service, medical expense reimbursement, rewarding assistance, basic medical insurance, and so on.MethodsUsing pooled cross-sectional data of poverty alleviation from 2014 to 2020 with a total of 83,521 observations aged 60+ in County J, Shaanxi Province in China, we calculate the MRPI for the older adults via a fuzzy set approach. Statistical difference testing is used to analyze the characteristics and trends of the MRPI. In policy evaluation, to address endogenous problems, the treatment effect model based on Heckman's two-stage regression and finite distributed lag model are used with a controlled township cluster structure.ResultsFrom 2014 to 2020, the MRPI shows a significant upward trend for older adults in rural China, and the health component takes the dominant MRPI position. Empirically, we find that the HPAP can significantly alleviate the MRPI of older adults. Furthermore, among the health poverty alleviation measures, basic medical insurance is the most effective anti-poverty policy to support older adults. Specifically, empirical evidence shows that there is a more statistically significant reduction in the MRPI with the HPAP for the sub-group of older adults with chronic diseases or disabilities.ConclusionBoth relativity and multidimensionality should be emphasized when analyzing poverty vis-Ă -vis the aging society, and for this, the MRPI is one of the effective tools. Comparing the relativity with the aged group engenders a more accurate understanding of their poverty situation. Moreover, the importance of the health component among all the four dimensions is more conducive to the detailed analysis of their poverty. The empirical analysis results show that regarding poverty reduction approaches in China, developing integrated health promotion systems is necessary and imminent, especially in the long run, such as long-term care insurance that covers typical disabled older adults with chronic diseases
DETRs with Hybrid Matching
One-to-one set matching is a key design for DETR to establish its end-to-end
capability, so that object detection does not require a hand-crafted NMS
(non-maximum suppression) to remove duplicate detections. This end-to-end
signature is important for the versatility of DETR, and it has been generalized
to broader vision tasks. However, we note that there are few queries assigned
as positive samples and the one-to-one set matching significantly reduces the
training efficacy of positive samples. We propose a simple yet effective method
based on a hybrid matching scheme that combines the original one-to-one
matching branch with an auxiliary one-to-many matching branch during training.
Our hybrid strategy has been shown to significantly improve accuracy. In
inference, only the original one-to-one match branch is used, thus maintaining
the end-to-end merit and the same inference efficiency of DETR. The method is
named H-DETR, and it shows that a wide range of representative DETR methods can
be consistently improved across a wide range of visual tasks, including
DeformableDETR, PETRv2, PETR, and TransTrack, among others. The code is
available at: https://github.com/HDETRComment: CVPR 2023. The code is available at: https://github.com/HDET
Brain damage in experimental neonatal hydrocephalus: correlations between diffusion tensor imaging and cytopathology
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