Relative Gliding Research Articles

OrtDet: An Orientation Robust Detector via Transformer for Object Detection in Aerial Images

The detection of arbitrarily rotated objects in aerial images is challenging due to the highly complex backgrounds and the multiple angles of objects. Existing detectors are not robust relative to the varying angle of objects because the CNNs do not explicitly model the orientation’s variation. In this paper, we propose an Orientation Robust Detector (OrtDet) to solve this problem, which aims to learn features that change accordingly with the object’s rotation (i.e., rotation-equivariant features). Specifically, we introduce a vision transformer as the backbone to capture its remote contextual associations via the degree of feature similarities. By capturing the features of each part of the object and their relative spatial distribution, OrtDet can learn features that have a complete response to any direction of the object. In addition, we use the tokens concatenation layer (TCL) strategy, which generates a pyramidal feature hierarchy for addressing vastly different scales of objects. To avoid the confusion of angle regression, we predict the relative gliding offsets of the vertices in each corresponding side of the horizontal bounding boxes (HBBs) to represent the oriented bounding boxes (OBBs). To intuitively reflect the robustness of the detector, a new metric, the mean rotation precision (mRP), is proposed to quantitatively measure the model’s learning ability for a rotation-equivariant feature. Experiments on the DOTA-v1.0, DOTA-v1.5, and HRSC2016 datasets show that our method improves the mAP by 0.5, 1.1, and 2.2 and reduces mRP detection fluctuations by 0.74, 0.56, and 0.52, respectively.

Gliding Vertex on the Horizontal Bounding Box for Multi-Oriented Object Detection.

Object detection has recently experienced substantial progress. Yet, the widely adopted horizontal bounding box representation is not appropriate for ubiquitous oriented objects such as objects in aerial images and scene texts. In this paper, we propose a simple yet effective framework to detect multi-oriented objects. Instead of directly regressing the four vertices, we glide the vertex of the horizontal bounding box on each corresponding side to accurately describe a multi-oriented object. Specifically, We regress four length ratios characterizing the relative gliding offset on each corresponding side. This may facilitate the offset learning and avoid the confusion issue of sequential label points for oriented objects. To further remedy the confusion issue for nearly horizontal objects, we also introduce an obliquity factor based on area ratio between the object and its horizontal bounding box, guiding the selection of horizontal or oriented detection for each object. We add these five extra target variables to the regression head of faster R-CNN, which requires ignorable extra computation time. Extensive experimental results demonstrate that without bells and whistles, the proposed method achieves superior performances on multiple multi-oriented object detection benchmarks including object detection in aerial images, scene text detection, pedestrian detection in fisheye images.

Does ‘gliding while gravid’ explain Rensch's rule in flying lizards?

Among species with sexual size dimorphism (SSD), taxa in which males are the larger sex have increasing SSD with increasing body size, whereas in taxa in which females are the larger sex, SSD decreases with body size: Rensch's rule. We show in flying lizards, a clade of mostly female-larger species, that SSD increases with body size, a pattern similar to that in clades with male-biased SSD or more evenly mixed SSD. The observed pattern in Draco appears due to SSD increasing with evolutionary changes in male body size; specifically divergence in body size among species that are in sympatric congeneric assemblages. We suggest that increasing body size, resulting in decreased gliding performance, reduces the relative gliding cost of gravidity in females, and switches sexual selection in males away from a small-male, gliding advantage and toward selection on large size and fighting ability as seen in many other lizards. Thus, selection for large females is likely greater than selection for large males at the smaller end of the body size continuum, whereas this relationship reverses for species at the larger end of the continuum. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 270–282.

The effects of skiing velocity on mechanical aspects of diagonal cross-country skiing

Cycle and force characteristics were examined in 11 elite male cross-country skiers using the diagonal stride technique while skiing uphill (7.5°) on snow at moderate (3.5 ± 0.3 m/s), high (4.5 ± 0.4 m/s), and maximal (5.6 ± 0.6 m/s) velocities. Video analysis (50 Hz) was combined with plantar (leg) force (100 Hz), pole force (1,500 Hz), and photocell measurements. Both cycle rate and cycle length increased from moderate to high velocity, while cycle rate increased and cycle length decreased at maximal compared to high velocity. The kick time decreased 26% from moderate to maximal velocity, reaching 0.14 s at maximal. The relative kick and gliding times were only altered at maximal velocity, where these were longer and shorter, respectively. The rate of force development increased with higher velocity. At maximal velocity, sprint-specialists were 14% faster than distance-specialists due to greater cycle rate, peak leg force, and rate of leg force development. In conclusion, large peak leg forces were applied rapidly across all velocities and the shorter relative gliding and longer relative kick phases at maximal velocity allow maintenance of kick duration for force generation. These results emphasise the importance of rapid leg force generation in diagonal skiing.

An in vivo subject-specific 3D functional knee joint model using combined MR imaging

We aim to quantitatively characterise the knee joint function in vivo under body-weight-bearing conditions via subject-specific models extracted from magnetic resonance (MR) data, in order to better understand the knee joint kinematic function in 3D. Six healthy volunteers without any record of knee abnormality were scanned using a combined MR imaging strategy to record quasi-squatting motion and 3D knee anatomy. After a semi-automatic segmentation to delineate tibio-femoral articulation components, motion data were mapped to the anatomical data using a bi-rigid registration in order to achieve six degrees of freedom. The individual knee joint function was characterised by analysing the tibio-femoral articulation contact mechanism based on the reconstructed models in 3D and MR images in 2D. Contact points were extracted and their trajectory was plotted on the tibia plateau. The 3D models clearly show the relative rotation and gliding between tibia and femur during global flexion. Within the measured flexion arc, the contact points move less between 30[Formula: see text] and 100[Formula: see text] on both tibial plateaux as compared to that on the rest of the flexion arc. Four out of the six volunteers showed a global pattern of less moving extent of contact points on the medial tibial plateau than on the lateral tibial plateau in both 3D and 2D. The proposed subject-specific model is able to characterise knee joint kinematic function. It provides a way to describe knee joint surface kinematics quantitatively, which may help to better understand the knee function and joint derangements.

An Analytical Model for Elucidating Tendon Tissue Structure and Biomechanical Function from in vivo Cellular Confocal Microscopy Images

Fibered confocal laser scanning microscopes have given us the ability to image fluorescently labeled biological structures in vivo and at exceptionally high spatial resolutions. By coupling this powerful imaging modality with classic optical elastography methods, we have developed novel techniques that allow us to assess functional mechanical integrity of soft biological tissues by measuring the movements of cells in response to externally applied mechanical loads. Using these methods we can identify minute structural defects, monitor the progression of certain skeletal tissue disease states, and track subsequent healing following therapeutic intervention in the living animal. Development of these methods using a murine Achilles tendon model has revealed that the hierarchical and composite anatomical structure of the tendon presents various technical challenges that can confound a mechanical analysis of local material properties. Specifically, interfascicle gliding can yield complex cellular motions that must be interpreted within the context of an appropriate anatomical model. In this study, we explore the various classes of cellular images that may result from fibered confocal microscopy of the murine Achilles tendon, and introduce a simple two-fascicle model to interpret the images in terms of mechanical strains within the fascicles, as well as the relative gliding between fascicles.

PRELIMINARY DESIGN OF A KNEE EXTERNAL FIXATOR BASED ON PLANAR GEOMETRIC SYNTHESIS

The paper presents the validation of a methodology for the optimal synthesis of a planar mechanical system able to reproduce knee kinematics in a limited range of motion. Such a mechanism could be effectively used in the design and placement of a moving external fixator for the knee joint articulation in either post-traumatic and pathological treatment or rehabilitation. The purpose is to help patient’s recovery through a limited and occasional movement of the articulation without loading the injured area. In order to validate the actual method, knee kinematics is estimated by means of plane radiographs of the articular joint of an healthy volunteer at different flexion angles. Each of the lateral radiographs shows the relative tibia-femur motion in different configurations. The whole movement is reconstructed by interpolation, assuming a relative gliding law. Geometric synthesis, based on Burmester’s theory, is thus used to identify a set of compatible four-bar-linkages (f.b.l.), which reproduce the estimated rigid body motion.

Guide modes at interface of photonic crystal heterostructures composed of different lattices

We have investigated the guide modes in two kinds of two-dimensional photonic crystal heterostructures by using the plane wave expansion method combined with the supercell technique. These heterostructures consist of different air cylinders embedded into host dielectric in different lattices. Namely, One heterostucture is composed of square cylinders in square lattice and hexagon cylinders in triangular lattice (SSTH heterostucture). The other heterostucture is composed of rectangular cylinders in rectangular lattice and circle cylinders in triangular lattice(RRTC heterostucture). We find that the SSTH heterostucture may produce guide modes in absolute photonic band gap (PBG) when introducing relative longitudinal gliding or transverse displacement of the sub-lattices along the interface of the heterostructure. But the RRTC heterostucture can produce guide modes in absolute PBG without any relative longitudinal gliding or transverse displacement. This feature is quite different from other pure dielectric photonic crystals heterostructures.

Chemical lithium insertion into sol–gel lamellar manganese dioxide MnO1.85·nH2O

Chemical lithium insertion in the sol–gel manganese oxide MnO1.85·nH2O has been performed using n-butyllithium as a reducing agent. Open-circuit voltage (OCV) experiments, IR, XRD and thermal analysis on lithiated samples LixMnO1.85·nH2O 0 < x⩽ 0.45 show that lithium insertion into the host lattice induces a slight structural change: from x= 0.05, a relative gliding of MnO6 layers occurs, leading to the transformation of the initial hexagonal structure into a closely related monoclinic phase. The higher the lithium content, the stronger the Li–hydrogen bond interactions which explains the contraction of the lattice observed along the c direction. The low magnitude of the structural changes is consistent with the high reversible behaviour found for this compound used as rechargeable cathodic material for lithium batteries.

Propulsive and gliding phases in four cross-country skiing techniques

The purpose of this study was to compare the relative durations of the propulsive and gliding phases between three skating techniques (1-skate, 2-skate, and offset) and the diagonal stride technique in elite cross-country skiers. Nine skiers of provincial and national level were videotaped with a Panasonic AG 170 camera. The camera speed was set at 30 frames.s-1 and the shutter speed at 1/500 s. The athletes were asked to ski at approximately 80% of their maximal skiing speed on a flat (50 m long) and on an uphill course (35 m long, 5 degrees grade). The relative propulsive phases of the skating techniques were significantly longer than those of the diagonal stride. The relative gliding phases were also longer with the skating techniques. In addition, velocities obtained while skiing with the diagonal stride were about 16% slower than those attained with the skating techniques, principally related to the longer cycle lengths observed with the skating techniques, while cycle rates were quite similar between all four techniques. The results of this study suggest that the longer relative phases of propulsion with the skating techniques may explain the greater speed attained with these techniques in comparison with the diagonal stride.

A modified kleinert Controlled Mobilization Splint following flexor tendon repair

The Controlled Mobilization Splint as described by Kleinert for use following flexor tendon repair has been modified to more closely simulate the normal range of motion of the fingers and in particular to increase the range of motion at the distal interphalangeal joint and so enhance the relative gliding of the flexor digitorum superficialis and flexor digitorum profundus tendons and hence possibly to reduce potential intertendinous adhesions.

The Crystal Structure and the Phase Transition of a Metastable Phase in the Au-37.8% Zn Alloy

The alloy of the composition of nearly Au:Zn=5:3 forms the β'-phase with the ordered β-brass type structure above 500°C. When this alloy is rapidly cooled from 600°C to room temperature, a metastable phase is formed, and if it is annealed at 200°C for more than an hour, it transforms into the stable phase, Au 5 Zn 3 . The crystal structure of the metastable phase has been determined by X-ray diffraction using single crystals. The unit cell is orthorhombic with the dimensions of a m =6.332, b m =8.953 and c m =4.477 kX, and a probable space group is Pmc 2 1 . The atomic arrangement is fundamentally of the body-centered cubic lattice type, but atoms are located in positions slightly shifted from the lattice points of the fundamental lattice. All of atoms have components of shifts along the c m -axis which are considered to be due to a relative gliding of every two (011) atomic planes of the original β'-phase lattice along the [01\bar1] direction. There are six equivalent orientation relationships between th...