• Title/Summary/Keyword: University of Oxford

Search Result 211, Processing Time 0.024 seconds

Sway buckling of down-aisle, spliced, unbraced pallet rack structures

  • Beale, R.G.;Godley, M.H.R.
    • Steel and Composite Structures
    • /
    • v.3 no.5
    • /
    • pp.307-320
    • /
    • 2003
  • This paper presents an efficient approach to the determination of the buckling loads of down-aisle, spliced, unbraced, pallet rack structures subjected to vertical and horizontal loads. A pallet rack structures is analysed by considering the stability equations of an equivalent free-sway column. The effects of semi-rigid beam-to-upright, splice-to-upright and base-plate-to-upright connections are fully incorporated into the analysis. Each section of upright between successive beam levels in the pallet rack is considered to be a single column element with two rotational degrees of freedom. A computer algebra package was used to determine modified stability equations for column elements containing splices. The influence of the position of splices in a pallet rack is clearly demonstrated.

Kinematic Analysis of Head and Trunk Movements of Young Adults while Climbing Stairs or a Ramp

  • Han, Jin-Tae
    • The Journal of Korean Physical Therapy
    • /
    • v.22 no.6
    • /
    • pp.21-28
    • /
    • 2010
  • Purpose: The purpose of this study was to investigate the kinematic adaptation of head and trunk to ascend stairs and a ramp. Subjects were healthy young adults. Three-dimensional kinematic patterns of head and trunk movements were examined during stair climbing and steeper ramp climbing. Methods: Fourteen young subjects with no history of chronic or acute musculoskeletal, cardiovascular or respiratory disorders took part in this experiment. Kinematic data were collected using a 6 camera Vicon system (Oxford Metrix, Oxford, England). Repeated measures ANOVA analyses were used to investigate the effect of gait mode on kinematics of the head and trunk. Results: The angle of the trunk while ascending stairs or a ramp was modified in three human planes (p<0.05). The angle of head and neck during the ascending of stairs or a ramp was not changed in the sagittal plane but was changed in the frontal and transverse planes (p<0.05). Conclusion: This study describes and discusses some basic kinematic mechanisms underlying the pattern of head and trunk changes during stair and ramp climbing and showed that postural adaptation of the head and trunk is necessary to maintain balance.

LOCALLY ENRICHED QUADTREE GRID NUMERICAL MODEL FOR NEARSHORE CIRCULATION IN THE SURF ZONE

  • Park, Koo-Yong
    • Water Engineering Research
    • /
    • v.1 no.3
    • /
    • pp.187-197
    • /
    • 2000
  • This paper describes an adaptive quadtree-based 2DH wave-current interaction model which is able to predict wave breaking, shoaling, refraction, diffraction, wave-current interaction, set-up and set-down, mixing processes (turbulent diffusion), bottom frictional effects, and movement of the land-water interface at the shoreline. The wave period-and depth-averaged governing equations are discretised explictly by means of an Adams-Bashforth second-order finite difference technaique on adaptive hierarchical staggered quadtree grids. Grid adaptation is achieved through seeding points distributed according to flow criteria(e.g. local current gradients). Results are presented for nearshore circulation at a sinusoidal beach. Enrichment permits refined modelling of important localised flow features.

  • PDF

Image Retrieval Based on the Weighted and Regional Integration of CNN Features

  • Liao, Kaiyang;Fan, Bing;Zheng, Yuanlin;Lin, Guangfeng;Cao, Congjun
    • KSII Transactions on Internet and Information Systems (TIIS)
    • /
    • v.16 no.3
    • /
    • pp.894-907
    • /
    • 2022
  • The features extracted by convolutional neural networks are more descriptive of images than traditional features, and their convolutional layers are more suitable for retrieving images than are fully connected layers. The convolutional layer features will consume considerable time and memory if used directly to match an image. Therefore, this paper proposes a feature weighting and region integration method for convolutional layer features to form global feature vectors and subsequently use them for image matching. First, the 3D feature of the last convolutional layer is extracted, and the convolutional feature is subsequently weighted again to highlight the edge information and position information of the image. Next, we integrate several regional eigenvectors that are processed by sliding windows into a global eigenvector. Finally, the initial ranking of the retrieval is obtained by measuring the similarity of the query image and the test image using the cosine distance, and the final mean Average Precision (mAP) is obtained by using the extended query method for rearrangement. We conduct experiments using the Oxford5k and Paris6k datasets and their extended datasets, Paris106k and Oxford105k. These experimental results indicate that the global feature extracted by the new method can better describe an image.