An Analysis of Manufacturing Precision of Involute Worms Using a Kinematical Model

The manufacturing precision of involute worms constitutes a major requirement. On the one hand, the worm constitutes the input element of the worm drive; secondly, the involute helical surface is the basic surface of an involute worm-hob. This paper presents an analytic comparison between the involute surfaces obtained using theoretical equations, kinematic simulation of the cutting and the surface charged with errors. The surface error is considered the distance along the normal direction to the theoretical surface, measured between this and the surface charged with simulated manufacturing errors. The main sources of errors are considered the center-error of the edge plane, the edge profile error and deviation of the axial feed direction from the axis of the worm. The theoretical results allow us to conclude that the influence of the edge profile error is the largest. It is followed by the parallelism error between the feed direction and the axis of the worm, and finally, the center error of the tool edge.

Numerical Modeling of Wall Pressure in Silo with and Without Insert

This paper presents a methodology based on the finite element method to simulate the flow of granular materials. Moreover, it allows proper estimation of dynamic pressure during silo discharge since this subject is still under discussion, especially for designing silos with an insert (an input element). A 2-D simulation of the discharge process of a cylindrical silo with cone and a central discharging orifice was performed. Two cases were studied, with and without using insert in silo. Numerical analysis was carried out with the help of the uncoupled arbitrary Lagrangian–Eulerian (ALE) approach. The resulting dynamic pressure distribution on the silo wall for each of the two cases was inferred numerically. The resulting values of pressure were compared with the results of the experimental study on a cylindrical metal silo to demonstrate the accuracy of the numerical model in determining the dynamic wall pressure, especially in the case of using an insert in silo during discharge.

Fuzzy mathematical risk preferences based on stochastic production function among medium-scale hog producers

Farmers’ risk preferences and degree of risk aversion affect their production and management decisions. According to Just-Pope stochastic production function model, we get the expression of the single element risk-aversion coefficients that include input element and hog slaughter absolute price, compared with the expression of relative price mean risk-aversion coefficients, it can directly observe the influence of the element and output price on single element risk-aversion coefficients. Based on the regression procedures and the calculation method of the average value of the element risk-aversion coefficients, mean risk-aversion coefficients of per household medium-scale hog producers are calculated in 76 households, 11 counties, Heilongjiang province. The results show that medium-scale hog producers are risk-averse, accounting for 96%; newborn animal weight and feed consumption affect hog producers’ degree of risk aversion. The former is the risk-reducing input element, while the latter is the risk-increasing input element.

Rollback and Compensation for an Easy Control Hydraulic Servo Joint

The easy control hydraulic servo joint is a key element for a reconfigurable robot and its response and control accuracy determine the performance of the robot. With the stepping motor as the input element the main parts of joint includes a rotational valve with the double orifice and the single-vane actuator. The basic structure and the working principle of joint are introduced. The mathematic model is established and the dynamic responses are analysed by using the digit simulation. From the results of simulation, a phenomenon of rollback in the process of response of joint is observed. With the simulation, the relationships between the rollback and parameters of structure are discussed. A digit PID controller is employed to reduce the effect of rollback to a great extent.

Cca-Secure Key Encapsulation Mechanism Based on Factoring Assumption

ABSTRACT In this article a key encapsulation mechanism is presented which is based on squaring function, where the input element is from QR+N, where QR+N denotes the signed quadratic residue group, and N is a Blum integer. The article presents the soundness, the efficiency and the proof of CCA security of the proposed mechanism

Label Fusion Strategy Selection

Label fusion is used in medical image segmentation to combine several different labels of the same entity into a single discrete label, potentially more accurate, with respect to the exact, sought segmentation, than the best input element. Using simulated data, we compared three existing label fusion techniques—STAPLE, Voting, and Shape-Based Averaging (SBA)—and observed that none could be considered superior depending on the dissimilarity between the input elements. We thus developed an empirical, hybrid technique called SVS, which selects the most appropriate technique to apply based on this dissimilarity. We evaluated the label fusion strategies on two- and three-dimensional simulated data and showed that SVS is superior to any of the three existing methods examined. On real data, we used SVS to perform fusions of 10 segmentations of the hippocampus and amygdala in 78 subjects from the ICBM dataset. SVS selected SBA in almost all cases, which was the most appropriate method overall.

INCORPORATING UNCERTAINTY IN NEURAL NETWORKS

We propose a method to incorporate the uncertainty of data in the computation process of neural networks. A measure of certainty is used on each input element in order to modulate the element's contribution to the whole input activity. The amount of certainty may result from knowledge about sensor data (e.g. detectable hardware faults or information from preprocessing steps) or may be determined in previous neurons. The method is developed and studied within the scope of the perceptron model and tested on an image processing application.

The Development of a Two-Dimensional Automatic Free-Form Mesh Generator

A fully-automatic free-form mesh generation method is described in this paper. The related mesh generator is capable of meshing planar regions. In addition to being fully-automatic, the method produces quadrilateral or triangular elements with aspect ratios near one. The input to the method includes the region’s boundary curves, the element size, and the mesh grading information. The method begins by decomposing the planar region to be meshed into convex subregions. Each subregion is meshed by first generating nodes on its boundaries using the input element size. The boundary nodes are then offset to mesh the subregion. The resulting meshes are merged together to form the final mesh. The free-form mesh generator and its related method has been tested and applied to a wide number of regions. Sample examples are presented.