Reference Circle Research Articles

URBAN SPRAWL, TRANSPORT AND VEHICLE ACCIDENTS IN GUADALAJARA’S METROPOLITAN AREA

URBAN SPRAWL, TRANSPORT AND VEHICLE ACCIDENTS IN GUADALAJARA’S METROPOLITAN AREA Caminos Serrano Luis Gerardo1, Curiel Ballesteros Arturo1 1Masters Program in Environmental Health, University of Guadalajara. Background Guadalajara’s strong attraction with respect to its regional environment and the population saturation of its territory is reflected in the increase in population growth rates of its neighboring municipalities, showing a high-intensity urban expansion. Due to this urban sprawl, people drive more and pollute more. The increase in transfer times can be linked to increased risks associated to expanding cities (Frumkin, Frank, Jackson. 2004). Aims Confirm that urban expansion, has been instrumental in the increased rates of vehicle accidents. Methods In order to establish a value for urban sprawl, a central zone of compact built was taken as the point of reference and concentric circles were drawn from this point—all with equal areas—in order to confirm the manner in which urban sprawl has increased over the years. Established the location of each vehicular accident within the municipality in the area of concern. Results Urban sprawl is verified in some specific areas. Traffic accidents have occurred mainly on two of the roads. These roads were designed before the occurrence of this expansion and have recently been modified to incorporate the entrance and exit points to these areas. From 2005 to 2010, the number of inhabited homes doubled, from 50,989 to 105,954; the same was observed with respect to the number of automobiles, which increased from 23,535 to 42,375. Nevertheless, the number of accidents between 2005 and 2010 increased from 353 to 1,289; that is, it did not double but rather increased four-fold. The same holds for the number of deaths, which rose from 12 per year to 40 per year. Conclusions The increase in vehicle accidents in Guadalajara’s metropolitan area is explained not by the population increase, but rather by a synergistic effect of urban sprawl.

Optimum Dataset Size and Search Space for Minimum Zone Roundness Evaluation by Genetic Algorithm

Roundness is one of the most common features in machining. The minimum zone tolerance (MZT) approach provides the minimum roundness error, i.e. the minimum distance between the two concentric reference circles containing the acquired profile; more accurate form error estimation results in less false part rejections. MZT is still an open problem and is approached here by a Genetic Algorithm. Only few authors have addressed the definition of the search space center and size and its relationship with the dataset size, which greatly influence the inspection time for the profile measurement and the convergence speed of the roundness estimation algorithm for a given target accuracy. Experimental tests on certified roundness profiles, using the profile centroid as the search space center, have shown that the search space size is related to the number of dataset points and an optimum exists, which provides a computation time reduction up to an order of magnitude.

A Frank scheme of determining the Burgers vectors of dislocations in a FCC crystal

A Frank scheme based on the Thompson’s tetrahedron is developed to calculate the Burgers vector of dislocations in a face-centered cubic (FCC) crystal during its plastic deformation. A Burgers circuit is located firstly in a deformed crystal with a reference circle surrounding one or more dislocations. The atom-to-atom sequence in a dislocation-free crystal corresponding to the Burgers circuit is determined not from a local reference lattice, but from the edge vectors of the Thompson’s tetrahedron and its mirrors. The final Burgers vector obtained by its Frank definition is accurate, regardless of the position, size and normal direction of the initial reference circle, as long as the same dislocations are surrounded. The present method is validated in determining the Burgers vectors for the dissociation of a perfect dislocation and for the complex reactions of the dislocations from a nanovoid in a deformed crystal under a uniaxial tensile loading.

Examination System for Accelerometer with Parallel Link Mechanism Displacement Calculation by Integrated Acceleration and Individual Correction of Accelerometers

This study focuses on a calculated displacement from acceleration profile with double integration. Structural displacement and vibrational response are important informations for safety inspection of buildings. Such inspection system requires multi point measurement with accelerometers. Because of piece to piece variations, individual examination is necessary to use a large number of accelerometers. For the purpose of individual high accuracy sensor test, this study proposes a new exciter device which converts rotation motion to sine wave vibration with parallel link mechanism. The proposed exciter provides accurate acceleration and assured circular displacement for sensor inspection. Experimental results determine a matrix with real sensor direction vectors. Sensitivities are also measured for each sensor direction by matching integrated orbit for the reference circle. These detailed parameters of multi-axis accelerometer are what conventional methods cannot determine.

零件矩形边界框区域自动提取算法及应用

A new automatic extraction-algorithm of parts bounding box is proposed for the purpose of improving the image processing speed.The reliability of this algorithm under isolated nosie and the effect of different threshold on the experimental result is analyzed.The anti-noise template is developed suitable for the chain board.The geometric parameters of circle in chain board are obtained by least square method and minimum zone reference circle method.The experiment result shows that this algorithm can inhibit isolated nosie well and the bounding box including target image can be found fast and accurately.

An Automated System for Image-to-Vector Georeferencing

Although modern imagery usually has latitude and longitude or similar coordinates to provide true world location, much potentially useful imagery lacks this information. This includes historical imagery, as well as modern imagery that may have lost its locational information through inappropriate processing. Its provision through the process of georeferencing is still primarily a manual procedure. This paper proposes an efficient, fully- automated solution for massively asymmetric image-to-vector georeferencing whereby an image of a relatively small geographic area is automatically located relative to a substantially larger vector map base. For control points, road intersections are automatically extracted from high resolution aerial or satellite imagery using the new concepts of reference circles and central pixels. For automated control point pair identification between image and vector map, an invariant point pattern matching approach is proposed based on shape invariance for similarity transforms and invariant area ratios for affine transforms. The matching algorithm necessitates only a small subset of image points and requires no additional information beyond pixel and map coordinates. Further, it tolerates inaccurate, missing and spurious points, and provides high performance with linear scalability. A final step performs transformation verification, globalization and optimization based upon an Iterative Closest Point Greedy algorithm. Experimentation shows that images covering a few city blocks with as few as 6 to 17 extracted road intersection points can be efficiently and correctly located using the road network of Dallas County, Texas, with over 80,000 intersections.

Research on the 3D Modeling Method of Epicycloids’ Bevel Gear Based on Pro/E

In order to obtain 3D solid model of an Oerlikon system’s prolate epicycloidal bevel gear by full generating processing, the solid modeling method for the gear was studied in Pro/E. First, Drawing benchmark circles (base on the circle and reference circle as well as tip circle and root circle)and involute tooth profile of virtual equivalent gears of both large end and small end of the real gear, and then an intercepted segment of prolate epicycloid which has the same trend to the tooth and is controlled by prolate epicycloidal equations is projected to the surface of the gear’s root cone for the sake of getting tooth curve along axial direction. In the end, along the tooth curve and on the root cone conducting a variable cross section solid scanning to tooth shaped cross section, a complete gear tooth will be gained and at last model establishing will be finished. This method provided digital basis for optimization design, reverse design and rapid prototyping of this kind of gear, and so its design efficiency is improved.

POWER LAW MAPPING IN HUMAN AREA PERCEPTION

We investigate how humans visually perceive and approximate area or space allocation through visual area experiments. The participants are asked to draw a circle concentric to the reference circle on the monitor screen using a computer mouse with area measurements relative to the area of the reference circle. The activity is repeated for triangle, square and hexagon. The area estimated corresponds to the area estimates of a participant (perceived) for a corresponding requested area to be drawn (stimulus). The area estimated fits very well (goodness of fit R2 > 0.97) to a power law given by r2α where r is the radius of the circle or the distance of the edge for triangle, square and hexagon. The power law fit demonstrates that for all shapes sampled, participants underestimated area for stimulus that are less than ~100% of the reference area and overestimated area for stimulus greater than ~100% of the reference area. The value of α is smallest for the circle (α∘ ≈ 1.33) and largest for triangle (α△ ≈ 1.56) indicating that in the presence of a reference area with the same shape, circle is perceived to be smallest among the figures considered when drawn bigger than the reference area, but largest when drawn smaller than the reference area. We also conducted experiments on length estimation and consistent with the results of Dehaene et al., Science 2008, we recover a linear relationship between the perceived length and the stimulus. We show that contrary to number mapping into space and/or length perception, human's perception of area is not corrected by the introduction of cultural interventions such as formal education.

Curves and surfaces with rational chord length parameterization

The investigation of rational varieties with chord length parameterization (shortly RCL varieties) was started by Farin (2006) who observed that rational quadratic circles in standard Bézier form are parametrized by chord length. Motivated by this observation, general RCL curves were studied. Later, the RCL property was extended to rational triangular Bézier surfaces of an arbitrary degree for which the distinguishing property is that the ratios of the three distances of a point to the three vertices of an arbitrary triangle inscribed to the reference circle and the ratios of the distances of the parameter point to the three vertices of the corresponding domain triangle are identical. In this paper, after discussing rational tensor-product surfaces with the RCL property, we present a general unifying approach and study the conditions under which a k-dimensional rational variety in d-dimensional Euclidean space possesses the RCL property. We analyze the entire family of RCL varieties, provide their general parameterization and thoroughly investigate their properties. Finally, the previous observations for curves and surfaces are presented as special cases of the introduced unifying approach.

The Influence of Crack on the Sound and Vibration Characteristic of Gear Structure

The gear structure is equivalent to disposed as a circinal plate, and also, reference circle cracks of gear are simulated by setting the arc direction crack. Because of the appearing of crack, it will divide the whole circinal plate into some areas, and set different polynomials of vibrational flexibility in every area, then using District Technology and Rayleigh-Ritz method, the dynamical characteristic of circinal plate with arc direction crack is analyzed, the influence of the type and size of crack on dynamical characteristic(natural frequency, modal shape etc.)of circinal plate are deep studied. On this basis, making use of Finite element method, the first some order mode of the acoustic character of cracked plate are investigated using discrete Rayleigh integral, and the distribution of sound pressure on the r=0.5m sphere surface is obtained. At the same time, the influence of different depth of crack on acoustic characteristic of gear disc are discussed, and the rule of influence of crack on radiated acoustic field is given out. This result shows that the influence of crack on radiated acoustic field of circinal plate with the increase crack depth is increscent. These provide a theoretic foundation for gear fault diagnosis using the dynamic and acoustic method in engineering.

Number of Points for Roundness Measurement - Measured Results Comparison

Number of Points for Roundness Measurement - Measured Results Comparison Paper deals with filtering roundness. It presents experimental results measured for roundness turning and cylindrical grinding. Roundness was measured using Prismo Navigator 5 coordinate measuring machine. Evaluation was done by four methods: Minimum zone reference circles (MZCI), Least squares reference circle (LSCI), Minimum circumscribed reference circle (MCCI) and Maximum inscribed reference circle (MICI). The filters used were: Gauss, Spline and no filter.

Design of Ultrasonic Transformer Vibrated Radically with Double Supports in Gear Honing

Ultrasonic vibration can reduce honing forces efficiently. As the honing wheel can be washed by ultrasonic cavitations of cooling liquid, its jams are decreased and the higher honing efficiency has obtained. Therefore, the combination of ultrasonic machining and gear honing is a method for gear fine machining with its wide application future. In the paper, to improve the rigidity, the ultrasonic vibration system adopted the structure of double supports as traditional honing machine, so the horn is symmetric. The machined gear was simplified into a circular thin plate with diameter of its reference circle and the horn was treated as its half as the symmetry; the frequency equations of the transformer were derived according to stress match under the condition that the half horn and plate of the transformer were considered at the same time; the frequency equations were derived based on the boundary conditions. Then the design parameters of the transformer were obtained as the frequency equation was solved computationally and expanded to the whole horn. The displacement, stress of the transformer was solved, too. Finally, the vibration mode of the transformer was analyzed by ANSYS. The results of theoretical and ANSYS analysis is consistent, which means the theoretical model and analysis method are correct.

Theory and application of plane elliptic multipoles for static magnetic fields

Standard textbooks on beam dynamics study the impact of the magnetic field quality on the beam using field representations based on circular multipoles. Iron dominated magnets, however, typically provide a good field region with a non-circular aspect ratio (i.e. an ellipse whose axis a is significantly larger than the axis b); a boundary not ideal for circular multipoles. The development of superconductors, originally driven to reach fields above ≈ 2 T , allows using them today in completely different fields: iron dominated DC magnets, to save the energy for coil powering as well as repeatedly fast ramped magnets. The cold mass of magnets, housed in common cryostats sectors, makes it tedious to implement additional correction magnets at a later stage, as it requires to warm up the sections where the magnets should be installed as well as unwelding the cryostat. Thus the field homogeneity of the magnets and its influence on the beam has to be thoroughly studied during the project planning phase. Elliptic multipoles, a new type of field expansion for static or quasi-static (here magnetic) two-dimensional fields, are proposed and investigated, which are particular solutions of the potential equation in plane elliptic coordinates obtained by the method of separation. The proper subsets of these particular solutions appropriate for representing static real or complex fields regular within an ellipse are identified. Formulas are given for computing expansion coefficients from given fields. The advantage of this new approach is that the expansion is valid, convergent and accurate in a larger domain, namely in an ellipse circumscribed to the reference circle of the common circular multipoles in polar coordinates. Formulas are derived for calculating the circular multipoles from the elliptical ones. The effectiveness of the approach was tested on many different magnet designs and is illustrated here on the dipole design chosen for the core synchrotron (SIS 100) of the FAIR project as well as on measurement data obtained by rotating coil probes.

Evaluating and defining the sharpness of intraocular lenses: Microedge structure of commercially available square-edged hydrophobic lenses

To evaluate the microstructure of the edges of currently available square-edged hydrophobic intraocular lenses (IOLs) in terms of their deviation from an ideal square. Berlin Eye Research Institute, Berlin, Germany. Sixteen designs of hydrophobic acrylic or silicone IOLs were studied. For each design, a +20.0 diopter (D) IOL and a +0.0 D IOL (or the lowest available plus dioptric power) were evaluated. The IOL edge was imaged under high-magnification scanning electron microscopy using a standardized technique. The area above the lateral-posterior edge, representing the deviation from a perfect square, was measured in square microns using reference circles of 40 microm and 60 microm of radius and the AutoCAD LT 2000 system (Autodesk). The IOLs were compared with an experimental square-edged poly(methyl methacrylate) (PMMA) IOL (reference IOL) with an edge design that effectively stopped lens epithelial cell growth in culture in a preliminary study. Two round-edged silicone IOLs were used as controls. The hydrophobic IOLs used, labeled as square-edged IOLs, had an area of deviation from a perfect square ranging from 4.8 to 338.4 microm(2) (40 microm radius reference circle) and from 0.2 to 524.4 microm(2) (60 microm radius circle). The deviation area for the square-edged PMMA IOL was 34.0 microm(2) with a 40 microm radius circle and 37.5 microm(2) with a 60 microm radius circle. The respective values for the +20.0 D control silicone IOL were 729.3 microm(2) and 1525.3 microm(2) and for the +0.0 D control silicone IOL, 727.3 microm(2) and 1512.7 microm(2). Seven silicone IOLs of 5 designs had area values that were close to those of the reference square-edged PMMA IOL. Several differences in edge finishing between the IOLs analyzed were also observed. There was a large variation in the deviation area from a perfect square as well as in the edge finishing, not only between different IOL designs but also between different powers of the same design. Clinically, factors such as the shrink-wrapping of the IOL by the capsule may even out or modify the influence of these variations in terms of preventing posterior capsule opacification.

Accessment of aperiodic spindle error motion in single circle

It's more difficult to obtain the evaluation result of aperiodic spindle error motion in single circle than of work-spice roundness. The evaluation model of aperiodic spindle error motions in single circle is provided based on the analysis of the definition and the observation of spindle ideal axis. For the model, the new set can be dealt with different evaluation method based on the computer, after the spindle error motions set transformed. Then the uniform evaluation criterion of minimum zone reference circles method is established, and also the effects surface uniform evaluation criterion. It's convenient to obtain the evaluation result by minimum zone reference circles method or maximum inscribed circle method or minimum circumscribed circle method, on the base of the two criterions. Moreover the appreciation precision is improved greatly, and also the appreciation efficiency.

Application of probability circles analysis to the construction of calibration curves for infra red spectroscopy

A new method, based on the presentation of initial data in the form of probability circles (PC), has been developed for constructing a calibration curve, which shows a monotonic dependence with respect to the given concentration. The centre of the reference probability circle is defined by its mean value and the radius of the circle is calculated as the value of the standard deviation of the sampling considered. The comparative probability circle is defined by the same corresponding parameters but rotated, relative to the initial reference circle, by an angle, which is related to the Pearson's correlation coefficient (PCC). The two parameters of the PCC and the statistical proximity factor (PCF), which defines the positions of the centres of the circles relative to each other, can be chosen as statistical parameters for the construction of the desired calibration curve. Experiments realized with the mixture of two liquids (chloroform serves as the basic matrix) and acetone (serves as an additive) confirm the efficiency of this new analytical method and demonstrate a possible increase sensitivity for the detection of lower concentration limit by approximately one order of magnitude. This new approach, which is free from model assumptions, and having very clear geometrical meaning, can be applied for different types of spectra and has many potential applications in the construction of calibration curves for different additives embedded within different matrices.

Deflectometer with synthetically generated reference circle for aspheric surface testing

Abstract A deflectometer with a synthetically generated reference circle is proposed for aspheric surface testing. Rotation and translation movements are combined to realize laser scanning and make the measurement of the aspheric surface in polar coordinates. It effectively improves the measurement precision for aspheric surfaces with large relative aperture. The measuring equipment is calibrated using a defocused standard spherical surface, and it achieves a precision of λ/5– λ/10 (λ=0.6328 μm ) , which is close to the precision of the interferometric method (λ/20). This testing technique based on laser deflectometry is capable of measuring most kinds of aspheric surfaces, especially those with large asphericity and those of concave shapes. The feasibility of the technique is shown and experimental results are presented.

ProcessDiffraction VI.2: New possibilities in manipulating electron diffraction ring patterns

A free computer program was introduced recently to process electron diffraction ring patterns. The program (called ProcessDiffraction) produces XDR-like output from the digitized version of the measured diffraction patterns. The enhanced functionality of V1.2 is summarized in the present paper.1.The program starts with a hint-window giving suggestions what can be done next. Hints change permanently as processing progresses. The hint-window can be switched off optionally. It is a complement to the Windows-style Help-system.2.The center of the rings is found by manually shifting the measured pattern until it overlaps with a generated reference circle. The computer can further refine the position of the center.3.Elliptical distortion of the measured pattern (NOT of the display, which is irrelevant) is corrected by adjusting the eccentricity and axis direction of the reference ellipse (distorted from the reference circle) until visually coincide with the measured ring.

Mapping the visual field to the optic disc in normal tension glaucoma eyes

Purpose To establish the anatomical relationship between visual field test points in the Humphrey 24-2 test pattern and regions of the optic nerve head (ONH) Design Cross-sectional study. Participants Glaucoma patients and suspects from the Normal Tension Glaucoma Clinic at Moorfields Eye Hospital. Methods Sixty-nine retinal nerve fiber layer (RNFL) photographs with well-defined RNFL defects and/or prominent bundles were digitized. An appropriately scaled Humphrey 24-2 visual field grid and an ONH reference circle, divided into 30° sectors, were generated digitally. These were superimposed onto the RNFL images. The relationship of visual field test points to the circumference of the ONH was estimated by noting the proximity of test points to RNFL defects and/or prominent bundles. The position of the ONH in relation to the fovea was also noted. Main outcome measures The sector at the ONH corresponding to each visual field test point, the position of the ONH in relation to the fovea, and the effect of the latter on the former. Results A median 22 (range, 4–58), of a possible 69, ONH positions were assigned to each visual field test point. The standard deviation of estimations was 7.2°. The position of the ONH was 15.5° (standard deviation 0.9°) nasal and 1.9° (standard deviation 1.0°) above the fovea. The location of the ONH had a significant effect on the corresponding position at the ONH for 28 of 52 visual field test points. Conclusions A clinically useful map that relates visual field test points to regions of the ONH has been produced. The map will aid clinical evaluation of glaucoma patients and suspects, as well as form the basis for investigations of the relationship between retinal light sensitivity and ONH structure.

Curvature of the Lower Lumbar Facet Joints

The curvature of the lower lumbar facet joints in the transverse plane was measured using an innovative computed tomographic approach, and its relationship with the orientation of the joints was evaluated. Two hundred three vertebral levels were examined in 116 patients with low back pain. Reference circles were used to quantify joint curvature. The mean curvature (+/- SD) at the levels L3-L4, L4-L5, and L5-S1 conformed to circles of 27.3 mm +/- 11.5; 35.1 mm +/- 14.6; and 51.0 mm +/- 34.5 in diameter respectively. The ratio between the curvature of the facets and their orientation was 62.6% +/- 19.0; 57.8% +/- 21.6; and 64.9% +/- 48.9. From L3-L4 down to L5-S1 the curvature of the facet joints decreases. The differences between L3-L4 and L4-L5 is smaller than between L4-L5 and L5-S1. The curvatures of the joints conform to circles that are in mean approximately 40% in diameter smaller than those to which their orientations conform.