Coordinates Of Intersection Point Research Articles

Time-domain Kirchhoff approximation extensions modeling of acoustic camera imagery with multiple scattering

High-frequency acoustic cameras have provided high-resolution sonar images to enable the development of signal processing algorithms, such as 3-D reconstruction, target recognition, and precision navigation. However, the lack of large datasets has hampered the development of such algorithms. In this context, this paper proposes a time-domain Kirchhoff approximation extensions (TDKAX)-based model to generate realistic acoustic camera images, capable of accounting for multiple scattering from arbitrary-shapetargets. The images are formed by a coherent summation of different orders of transient echoes, along with a pipeline of the range conversion, time-varying gain compensation, noise addition, and image rendering. Validating the proposed model using tank experiments of isolated cylindrical concave reflectors, we then present the ray paths based on the coordinates of intersection points. They can help interpret the mechanism of image features in the absence of amplitude information. Results demonstrate that, with the temporal and spatial coherence of different orders of scattering, the proposed model successfully reproduces forward-looking sonar (FLS) images with multiple scattering arcs and coherent speckles.

Prediction and Optimization Algorithm for Intersection Point of Spatial Multi-Lines Based on Photogrammetry.

The basic theory of photogrammetry is mature and widely used in engineering. The environment in engineering is very complex, resulting in the corners or multi-line intersections being blocked and unable to be measured directly. In order to solve this problem, a prediction and optimization algorithm for intersection point of spatial multi-lines based on photogrammetry is proposed. The coordinates of points on space lines are calculated by photogrammetry algorithm. Due to the influence of image point distortion and point selection error, many lines do not strictly intersect at one point. The equations of many space lines are used to fit their initial value of intersection point. The initial intersection point is projected onto each image, and the distances between the projection point and each line on the image plane are used to weight the calculated spatial lines in combination with the information entropy. Then the intersection point coordinates are re-fitted, and the intersection point is repeatedly projected and recalculate until the error is less than the threshold value or reached the set number of iterations. Three different scenarios are selected for experiments. The experimental results show that the proposed algorithm significantly improves the prediction accuracy of the intersection point.

A Virtual-Movement Scheme for Eliminating Spot-Positioning Errors Applicable to Quadrant Detectors

Traditionally, spot-positioning algorithms applied in quadrant detector (QD) face some dilemmas, such as blind area between each quadrant, spot shape shift with Gaussian distribution distortion, and also restricted measurement range. In this article, a virtual-movement scheme, which is to build a mapping relationship between spot position and captured luminous energy of photodetectors, based on equations in mathematical physics, is proposed to resolve the above three problems. On the grounds of the proposed scheme, with establishment of spot-trail functions, the actual position of the spot can be obtained by solving the coordinates of intersection point formed by more than one spot virtual-movement trails. Furthermore, a series of novel algorithms capable of theoretically eliminating the errors caused by blind area and Gaussian distribution distortion and maximumly enlarging detecting range is devised. Significantly, the devised algorithms do not have problems of nonlinearity compensation since we do not depend on any fitting method but to solve the exact position of spot centroid. By modifying integral boundaries, the devised algorithms can be applied in any shape of existing 4-QD or promising $n$ -QD. Taking circular and square 4-QDs as two typical examples in this work, the devised algorithms have excellent performances in both types, whether spots near or far away from 4-QD’s center. With an energy-distribution model and the utilization of tolerance zones, wide measurement range and superhigh accuracy are verified both qualitatively and quantitatively. The devised algorithms have also been experimentally demonstrated to work effectively. The proposed scheme is believed to be capable of eliminating the spot-positioning errors in diverse $n$ -QD and provide wide application prospects for different types of quadrant photodetectors used in many cutting-edge areas, including optical manipulation, laser guidance, as well as quantum communication.

Mathematical modeling of mouse cell’s conductivity in pulsed electric field

Based on the approximation by algebraic and transcendental functions, non-linear mathematical models were built for the experimentally obtained dependences of the conductivity of mouse’s reproductive and embryonic cells on the strength of pulsed electric field applied. The approximation of experimental data was performed by the use of least squares method. The finding of extrema, inflection, intersection and curvature of approximating functions were carried out. To find out these characteristic points, the classical mathematical analysis methods were used. For this, the well-known methods of analytical geometry and the algebraic methods for solving equations were used. In addition, to calculate the coordinates of intersection points and curvature, the 1st and 2nd derivatives of non-linear functions were determined. The relationship was established between the calculated coordinates of characteristic points and the modes of membrane electroporation during the linear growth of electric field strength applied to a cell. The constructed mathematical models of experimental conductometric curves made it possible to calculate the strength of pulsed electric field, which is necessary and sufficient for the implementation of any electro-manipulation technologies based on the phenomenon of electroporation.

Fast and robust mesh arrangements using floating-point arithmetic

We introduce a novel algorithm to transform any generic set of triangles in 3D space into a well-formed simplicial complex. Intersecting elements in the input are correctly identified, subdivided, and connected to arrange a valid configuration, leading to a topologically sound partition of the space into piece-wise linear cells. Our approach does not require the exact coordinates of intersection points to calculate the resulting complex. We represent any intersection point as an unevaluated combination of input vertices. We then extend the recently introduced concept of indirect predicates [Attene 2020] to define all the necessary geometric tests that, by construction, are both exact and efficient since they fully exploit the floating-point hardware. This design makes our method robust and guaranteed correct, while being virtually as fast as non-robust floating-point based implementations. Compared with existing robust methods, our algorithm offers a number of advantages: it is much faster, has a better memory layout, scales well on extremely challenging models, and allows fully exploiting modern multi-core hardware with a parallel implementation. We thoroughly tested our method on thousands of meshes, concluding that it consistently outperforms prior art. We also demonstrate its usefulness in various applications, such as computing efficient mesh booleans, Minkowski sums, and volume meshes.

Graphical and computational methods for determining the stability constants of mono- and polynuclear complexes with a common intersection point of the family of formation curves

Aqueous polynuclear systems have been analyzed, for which the family of formation curves intersects at a common point. The analyzed graphical and computational method for determining the stability constants can be used as initial values within the iterative calculation process. In some cases, the stability constants are calculated using only the coordinates of the common intersection point. The obtained equations could be of special interest when the experimental data can be interpreted in several models. In these cases, given the large volume of experimental data, the calculation is simple and the model can certainly be chosen with high safety. The obtained equations may also be applied for critical evaluation of tabular data if the coordinates of the intersection point are known. A series of real polynuclear systems have been analyzed and useful conclusions have been made.

Fractional‐order PID servo control based on decoupled visual model

SummaryA decoupled visual model and a fractional PID controller are designed aiming at the problem of the view distortion in the fillet weld welding process. Firstly, the intersection point coordinates of two laser stripes are selected as the image characteristics, and the decoupled visual model is designed to the tracking control of the fillet weld seam so that the control value in two directions is decoupled, reducing the difficulty of control. In addition to this, the image may produce distortion in the dynamic tracking process, causing nonlinearity and coupling in two directions. To solve this problem, the fractional‐order PID controller is designed so that the adjustment range and the control ability are improved better than the traditional PID controller. Some experiments verify that the desired performance can be achieved by using the proposed methods.

Analytical Study on the Influence of Parasitic Elements in a Memristor

We study a memristive circuit with included parasitic elements, such as capacitance and inductance. In the multiple-scale scheme, we analytically show how the parasitic elements affect the voltage and the current. Finally, we provide an analytical expression for the intersection point coordinates, through which we discuss the functional behavior of the pinched hysteresis loop versus the operating frequency and the parasitic elements.

Changing the magnetic field intensity during the motion of spacecraft

In this paper the change of the intensity vector of geomagnetic field during the motion of the spacecraft in orbit in direct dipole model was investigated. The dependences of the intersection point coordinates of the vector intensity of the geomagnetic field with the unit radius Earth sphere were found, their graphs were built and their extremes were determined. The relations of the intersection point velocity of the vector intensity of the geomagnetic field to the unit radius Earth sphere were found, their graphs were built and their extremes determined. The graphs of each component of the geomagnetic field along the trajectory of the spacecraft and the combined graphs were built.

Development of normalized spectra manipulating spectrophotometric methods for simultaneous determination of Dimenhydrinate and Cinnarizine binary mixture

Simultaneous determination of Dimenhydrinate (DIM) and Cinnarizine (CIN) binary mixture with simple procedures were applied. Three ratio manipulating spectrophotometric methods were proposed. Normalized spectrum was utilized as a divisor for simultaneous determination of both drugs with minimum manipulation steps. The proposed methods were simultaneous constant center (SCC), simultaneous derivative ratio spectrophotometry (S1DD) and ratio H-point standard addition method (RHPSAM). Peak amplitudes at isoabsorptive point in ratio spectra were measured for determination of total concentrations of DIM and CIN. For subsequent determination of DIM concentration, difference between peak amplitudes at 250nm and 267nm were used in SCC. While the peak amplitude at 275nm of the first derivative ratio spectra were used in S1DD; then subtraction of DIM concentration from the total one provided the CIN concentration. The last RHPSAM was a dual wavelength method in which two calibrations were plotted at 220nm and 230nm. The coordinates of intersection point between the two calibration lines were corresponding to DIM and CIN concentrations. The proposed methods were successfully applied for combined dosage form analysis, Moreover statistical comparison between the proposed and reported spectrophotometric methods was applied.

Calculating the Coordinates of Intersection of the Concentric Circular Arcs with a Line by Means of Approximate Calculation Method and Examining Its Preciseness

In closed places such as cinemas, theaters, and conservatories locating the seats on concentric circular arcs may be required. In this case, defining the coordinates of intersecting points of side walls is needed to calculate the coordinates of seats according to a local coordinate system defined in the hall. Rigorous and approximate calculation methods, which have been applied to calculating the coordinates of intersection points with the concentric circular arcs and a line that is not in the radial direction, have been explained. The influence of the approximate calculation method on the accuracy of the position of intersection points, on a defined numerical model, has been examined in relation to various variables. In the numerical model, the locations of the tip of a line and the intersection point where the first circle arc and this line intersect were considered fixed. The angle values between radial direction passing through the first intersection point and the line passing through the concerned point and the distance along with the circle arcs and radius values of the first arc were considered variables. By taking these factors into consideration, the coordinates of the other intersection points, the differences among the calculated coordinates, and their accuracy of position were calculated by means of rigorous and approximate calculation methods. The graphical representation of the accuracies of the positions found were drawn and analyzed, and the findings and opinions were stated.

Approaches to parametric element constructions and dynamic analyses of spur/helical gears including modifications and undercutting

This paper presents approaches to element constructions and dynamic analyses for involute spur/helical gears, including cylindrical and conical categories. High quality elements for gear dynamics can be generated automatically and parametrically. Many design parameters are incorporated such as pressure angle and correction factor for examples. Besides, crucial influential factors including tip relief, crowning modification, and undercutting are also included. At first, the equations of involutes, fillets, and other curves for teeth are derived after applying coordinate transformation and gear principles to transverse cross section profiles of a rack cutter. Accordingly, tooth profiles of wide types of gears with abundant design considerations can be incorporated. The coordinates of intersection point among nonlinear tooth profiles are obtained, using the Newton–Raphson method. Then, no CAD geometric model required, meshed elements are constructed directly, using the profile equations of the gears via a C code. After that, elements of several gears are created to demonstrate the effectiveness of the presented method. Finally, dynamic responses of spur and helical gear pairs are calculated by LS-DYNA. The dynamic fillet stress of the spur gear pair is compared with an experimental result. It is expected that the proposed approach by the general purpose finite element software can be applied in gear dynamics, incorporating wide design and manufacturing considerations.

목표물에 근접한 위치데이터를 사용한 2차원 위치추정방법

본 논문에서는 목표의 위치를 결정하기 위해 사용되는 삼각법을 개선한 위치추정 방법을 제안한다. 제안하는 방법은 세 원간의 교점들을 통해 목표의 위치를 추정한다. 이 방법을 통해 결정된 목표의 위치는 기존의 방법과 같이 관측지역 중심에서 높은 정밀도를 갖고 기존의 방법에서 큰 오차를 갖는 관측지점 주변에서도 높은 정밀도를 갖는다. 이 방법은 기존의 방법보다 최대오차에서 40.89%, 평균오차에서 40.30%가 줄었다. This paper describes an improved location determination scheme based on the triangulation method calculating a target position. The proposed scheme uses coordinates of intersection points of three circles each generated by measurement of an observer. The target position obtained from the proposed scheme has higher accuracy not only at the vicinity, but also at the periphery of the observation area. The maximum error and the average error with the proposed scheme are reduced by 40.89% and 40.30%, respectively, with respect to conventional methods.