Variable center to center distance of nucleosomes in chromatin

1982 ◽  
Vol 154 (3) ◽  
pp. 515-523 ◽  
Author(s):  
Ariel Prunell ◽  
Roger D. Kornberg
Keyword(s):  
Center Distance ◽  
Variable Center

scholarly journals Synthesis of a ten-link tooth-lever differential roller transmission mechanism

2021 ◽  
Vol 304 ◽  
pp. 02010
Author(s):  
Abdusalam Abdukarimov ◽  
Sanjarbek Madaminov ◽  
Asrorbek Abdullajonov
Keyword(s):  
Scientific Research ◽  
Transmission Mechanism ◽  
Dynamic Synthesis ◽  
Transmission Mechanisms ◽  
Analytical Review ◽  
Line Passing ◽  
Roller Machine ◽  
Differential Transmission ◽  
Center Distance ◽  
Variable Center

This article deals with the synthesis of a ten-link tooth-lever differential transmission mechanism. The article contains an analytical review of modern scientific research on the synthesis of tooth-lever differential transmission mechanisms of roller machines with a variable center distance of the working shafts; a method for the synthesis of toothlever differential transmission mechanisms of roller machines with a variable center distance of the working shafts described on the example of a ten-link tooth-lever differential transmission mechanism; the conditions for the synthesis of the mechanism given and substantiated when this mechanism is used in a roller machine; one of its working shafts has the ability to rotate about its own axis, and the second working shaft, in addition to rotation about its own axis, has the ability to move relative to the first working shaft along a line passing through the center the axes of rotation of both working shafts; the geometric synthesis of the tooth and lever contours of the mechanism, the dynamic synthesis of the mechanism, taking into account the angles of pressure between the lever link of the lever contour of the mechanism, which allows us to determine the optimal working position of the mechanism where the angles of pressure are within acceptable limits; the graphs of changes in the angles of pressure between the links of the lever contour of the mechanism, plotted depending on its position.

The assembling of machine tool’s change gear quadrants based on modernized sets of gears

2020 ◽  
pp. 309-312
Author(s):  
A.P. Fot
Keyword(s):  
Computer Modeling ◽  
Analytical Methods ◽  
Machine Tools ◽  
Software Tool ◽  
Design Constraints ◽  
Center Distance ◽  
Variable Center

A method of assembling the twin-paired change gear quadrant with variable center distance that used on different metalworking machine tools is proposed. The possibility to increase the quality and reducing time of gears adjustment is proved — increase number of gear ratios provided by the modernized set of change gears while the number of change gears in set remains constant. Sets are created based on software tool executing the adjustment of twin-paired change gear quadrants regarding the primary kinematic and design constraints of a machine. The analytical methods and methods of computer modeling are used.

Effect of Contact Ratio on Spur Gear Dynamic Load With No Tooth Profile Modifications

1996 ◽  
Vol 118 (3) ◽  
pp. 439-443 ◽  
Author(s):  
Chuen-Huei Liou ◽  
Hsiang Hsi Lin ◽  
F. B. Oswald ◽  
D. P. Townsend
Keyword(s):  
Dynamic Load ◽  
Spur Gear ◽  
Tooth Size ◽  
Contact Ratio ◽  
Gear Dynamics ◽  
Wide Range ◽  
Gear Contact ◽  
Center Distance ◽  
Selection Of ◽  
Better Than

This paper presents a computer simulation showing how the gear contact ratio affects the dynamic load on a spur gear transmission. The contact ratio can be affected by the tooth addendum, the pressure angle, the tooth size (diametral pitch), and the center distance. The analysis presented in this paper was performed by using the NASA gear dynamics code DANST. In the analysis, the contact ratio was varied over the range 1.20 to 2.40 by changing the length of the tooth addendum. In order to simplify the analysis, other parameters related to contact ratio were held constant. The contact ratio was found to have a significant influence on gear dynamics. Over a wide range of operating speeds, a contact ratio close to 2.0 minimized dynamic load. For low-contact-ratio gears (contact ratio less than two), increasing the contact ratio reduced gear dynamic load. For high-contact-ratio gears (contact ratio equal to or greater than 2.0), the selection of contact ratio should take into consideration the intended operating speeds. In general, high-contact-ratio gears minimized dynamic load better than low-contact-ratio gears.

scholarly journals A multivariate intersection over union of SiamRPN network for visual tracking

2021 ◽  
Author(s):  
Zhihui Huang ◽  
Huimin Zhao ◽  
Jin Zhan ◽  
Huakang Li
Keyword(s):  
Aspect Ratio ◽  
Visual Tracking ◽  
Target Location ◽  
Coincidence Degree ◽  
Distance Ratio ◽  
Geometric Factors ◽  
Fast Motion ◽  
Definition Of ◽  
Overlap Area ◽  
Center Distance

AbstractSiamPRN algorithm performs well in visual tracking, but it is easy to drift under occlusion and fast motion scenes because it uses $$\ell _1$$ ℓ 1 -smooth loss function to measure the regression location of bounding box. In this paper, we propose a multivariate intersection over union (MIOU) loss in SiamRPN tracking framework. Firstly, MIOU loss includes three geometric factors in regression: the overlap area ratio, the center distance ratio, and the aspect ratio, which can better reflect the coincidence degree of target box and prediction box. Secondly, we improve the definition of aspect ratio loss to avoid gradient explosion, improve the optimization performance of prediction box. Finally, based on SiamPRN tracker, we compared the tracking performance of $$\ell _1$$ ℓ 1 -smooth loss, IOU loss, GIOU loss, DIOU loss, and MIOU loss. Experimental results show that the MIOU loss has better target location regression than other loss functions on the OTB2015 and VOT2016 benchmark, especially for the challenges of occlusion, illumination change and fast motion.

scholarly journals Myopia Control with Combination Low-Dose Atropine and Peripheral Defocus Soft Contact Lenses: A Case Series

2021 ◽  
pp. 548-554
Author(s):  
Nir Erdinest ◽  
Naomi London ◽  
Nadav Levinger ◽  
Yair Morad
Keyword(s):  
Low Dose ◽  
Contact Lenses ◽  
Case Series ◽  
Concentric Circle ◽  
Retrospective Case ◽  
Soft Contact ◽  
Myopia Progression ◽  
Soft Contact Lenses ◽  
Center Distance ◽  
Myopia Control

The goal of this retrospective case series is to demonstrate the effectivity of combination low-dose atropine therapy with peripheral defocus, double concentric circle design with a center distance soft contact lenses at controlling myopia progression over 1 year of treatment. Included in this series are 3 female children aged 8–10 years with progressing myopia averaging −4.37 ± 0.88 D at the beginning of treatment. Their average annual myopic progression during the 3 years prior to therapy was 1.12 ± 0.75 D. They had not attempted any myopia control treatments prior to this therapy. The children were treated with a combination of 0.01% atropine therapy with spherical peripheral defocus daily replacement soft lenses MiSight<sup>®</sup> 1 day (Cooper Vision, Phoenix, AZ, USA). They underwent cycloplegic refraction, and a slit-lamp evaluation every 6 months which confirmed no adverse reactions or staining was present. Each of the 3 children exhibited an average of 0.25 ± 0.25 D of myopia progression at the end of 1 year of treatment. To the best of the authors’ knowledge, this is the first published study exhibiting that combining low-dose atropine and peripheral defocus soft contact lenses is effective at controlling children’s moderate to severe myopia progression during 1 year of therapy.

A Hard C-Means Clustering Algorithm Incorporating Membership KL Divergence and Local Data Information for Noisy Image Segmentation

2017 ◽  
Vol 32 (04) ◽  
pp. 1850012 ◽  
Author(s):  
R. R. Gharieb ◽  
G. Gendy ◽  
H. Selim
Keyword(s):  
Image Segmentation ◽  
Membership Function ◽  
Clustering Algorithm ◽  
Clustering Algorithms ◽  
Cluster Center ◽  
Local Data ◽  
Cluster Membership ◽  
Kl Divergence ◽  
Clustering Approach ◽  
Center Distance

In this paper, the standard hard C-means (HCM) clustering approach to image segmentation is modified by incorporating weighted membership Kullback–Leibler (KL) divergence and local data information into the HCM objective function. The membership KL divergence, used for fuzzification, measures the proximity between each cluster membership function of a pixel and the locally-smoothed value of the membership in the pixel vicinity. The fuzzification weight is a function of the pixel to cluster-centers distances. The used pixel to a cluster-center distance is composed of the original pixel data distance plus a fraction of the distance generated from the locally-smoothed pixel data. It is shown that the obtained membership function of a pixel is proportional to the locally-smoothed membership function of this pixel multiplied by an exponentially distributed function of the minus pixel distance relative to the minimum distance provided by the nearest cluster-center to the pixel. Therefore, since incorporating the locally-smoothed membership and data information in addition to the relative distance, which is more tolerant to additive noise than the absolute distance, the proposed algorithm has a threefold noise-handling process. The presented algorithm, named local data and membership KL divergence based fuzzy C-means (LDMKLFCM), is tested by synthetic and real-world noisy images and its results are compared with those of several FCM-based clustering algorithms.

Research on the Friction Performance of Bionic Surface Based on the Clamber Animal Foot Pad

2013 ◽  
Vol 427-429 ◽  
pp. 298-301
Author(s):  
Chun Jian Su ◽  
Zhou Yu Fu ◽  
Hui Sun ◽  
Xiao Shen
Keyword(s):  
Sliding Friction ◽  
External Surface ◽  
Surface Friction ◽  
Friction Mechanism ◽  
Micro Particles ◽  
Bionic Surface ◽  
Friction Performance ◽  
Foot Pad ◽  
The Mathematical Model ◽  
Center Distance

The clamber animal foot pads were researched by the Super Depth of Field3D Microscopic System marked VHX-600 and the flexible non-smooth surface friction mechanism of clamber animal foot pad was analysed through bionic tribology. The total friction includes two aspects: a) The sliding friction caused by the adsorbability between clamber animal foot pad and external surface. b) The embedding resistance caused by the external surface micro particles embedded into clamber animal foot pad. The mathematical model of single convex hull was built and the different center distance bionic surfaces were designed, the friction contact simulation of bionic surface was done by ANSYS and the friction performance of bionic surface was verified through the plane friction testbed.

The Detection Method of Lane Line Based on the Improved Otsu Threshold Segmentation

2015 ◽  
Vol 741 ◽  
pp. 354-358 ◽  
Author(s):  
Yang Shan Tang ◽  
Dao Hua Xia ◽  
Gui Yang Zhang ◽  
Li Na Ge ◽  
Xin Yang Yan
Keyword(s):  
Image Segmentation ◽  
Processing Time ◽  
Detection Method ◽  
Segmentation Algorithm ◽  
Test Results ◽  
Threshold Segmentation ◽  
Otsu Method ◽  
Time Requirements ◽  
Lane Line ◽  
Center Distance

For overcoming the shortage of Otsu method, proposed an improved Otsu threshold segmentation algorithm. On the basis of Otsu threshold segmentation algorithm, the gray level was divided into two classes according to the image segmentation, to determine the best threshold by comparing their center distance, so as to achieve peak line recognition under the condition of multiple gray levels. Then did experiments on image segmentation of the lane line with MATLAB by traditional Otsu threshold segmentation algorithm and the improved algorithm, the threshold of traditional Otsu threshold segmentation algorithm is 144 and the threshold of the improved Otsu threshold segmentation algorithm is 131, the processing time is within 0.453 s. Test results show that the white part markings appear more, the intersection place of white lines and the background is more clear, so this method can identify lane markings well and meet the real-time requirements.

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