GEOMETRIC DESIGN OF DEPLOYABLE/RETRACTABLE MAST

To simplify the complicated design process of deployable/retractable structures, a new design process is developed. The process is divided into three phases： the concept design phase, the model phase and the optimization phase. In each phase, different parameter targets have to be fulfilled. According to three phases, a deployable/retractable mast composed of four right triangle prism modules in the longitudinal direction is designed. It can be deployed and folded simultaneously by the linear movements of sleeve-joints. The deployable and retractable movement of the mast is analyzed and key joint forms are designed. Then bar diameters and joint forms are modified based on mast structural mechanics characteristics in the optimization phase. Finally a 1：1 scaled model mast is built to verify the design and the optimization. Analytical results show that the model mast has the advantages of simple locking mechanism, fewer types of joints and bars, so it can be easily manufactured.

Automatic Horizontal Road Design Information Extraction from Georeferenced Polygonals： A Brazilian Federal Highway Network Study

Road geometric design data are a vital input for diverse transportation studies. This information is usually obtained from the road design project. However, these are not always available and the as-built course of the road may diverge considerably from its projected one, rendering subsequent studies inaccurate or impossible. Moreover, the systematic acquisition of this data for the entire road network of a country or even a state represents a very challenging and laborious task. This study＇s goal was the extraction of geometric design data for the paved segments of the Brazilian federal highway network, containing more than 47,000 km of highways. It presents the details of the method＇s adoption process, the particularities of its application to the dataset and the obtained geometric design information. Additionally, it provides a first overview of the Brazilian federal highway network composition （curves and tangents） and geometry.

A NEW SYSTEM FOR COMPUTER AIDED PATTERN DESIGN——CAPDS

This paper proposes a new computer aided pattern design system(CAPDS)in which a uniformmathematical expression is used to construct different objects. In the geometric model, 3 B-splineis adopted as a line model. The new system with uniform mathematical expression has the distin-guishing features: curve smoothness and fidelity, convenience to process graphic data in thedatabase and etc.. This paper presents the data structure, the program structure and also the implementation.

Analysis of the Relations between Highway Geometric Design and Traffic Safety in Bangladesh,China,and America

Transportation plays a critical role in the economic sector in Bangladesh.Since its independence,infrastructure has been developing rapidly,includ-ing land,water,and air transportation.National economy is increasing at a relatively high rate,leading to the better-off of people’s lives.As the living standards keep improving,people are more concerned about safety issues in transportation.This article makes an analysis of the status quo of traffic safety in Bangladesh and compares the Bangladeshi code with American code AASHTO from the geometric aspects of horizontal and vertical align-ment,in an effort to provide reference to the highway design in Bangla-desh.Through a reasonable design,the traffic safety will be under control and accident rate as well as economic loss will be minimized.

Global Continuity Adjustment and Local Shape Optimization Technique for Complex Trimmed Surface Model

Smoothly stitching multiple surfaces mainly represented by B-spline or NURBS together is an extremely important issue in complex surfaces modeling and reverse engineering. In recent years, a lot of progress has been made in smooth join of non-trimmed surface patches, while there has been seldom research on smoothly stitching trimmed surface patches together. This paper studies the problem of global continuity adjustment, damaged hole repair and local shape optimization for complex trimmed surface model, and presents a uniform scheme to deal with continuity adjustment of trimmed surfaces and geometric repair of local broken region. Constrained B-spline surface refitting technique and trim calculation are first utilized to achieve global G^1 continuity, and then local shape optimization functional is adopted to reduce fitting error and improve local quality of refitted surface patch. The proposed approach is applied to a discontinuity ship hull surface model with an irregular hole, and the result demonstrates the validation of our method. Furthermore, on the premise of global continuity, the proposed locally repairing damaged surface model provides a better foundation for following research work, such as topology recovery technique for complex surface model after geometric repair.

Approximate merging of B-spline curves and surfaces

Applying the distance function between two B-spline curves with respect to the L2 norm as the approximate error, we investigate the problem of approximate merging of two adjacent B-spline curves into one B-spline curve. Then this method can be easily extended to the approximate merging problem of multiple B-spline curves and of two adjacent surfaces. After minimizing the approximate error between curves or surfaces, the approximate merging problem can be transformed into equations solving. We express both the new control points and the precise error of approximation explicitly in matrix form. Based on homogeneous coordinates and quadratic programming, we also introduce a new framework for approximate merging of two adjacent NURBS curves. Finally, several numerical examples demonstrate the effectiveness and validity of the algorithm.

Anti-detection technology of cat eye target based on decentered field lens

Optoelectronic imaging equipment is easy to expose to active laser detection devices because of ＂cat eye＂ effect. In this paper, we propose a new structure of optical system to reduce the retroreflector effect of a cat eye target. Decentered field lens structure is adopted in the design without sacrificing imaging quality and clear aperture. An imaging system with±30° field of view is taken for example. The detailed design and simulation results are presented. The results indicate that this kind of optical system can reduce the retroreflection signal substantially and maintain acceptable imaging performance.

Computation of lower derivatives of rational triangular Bézier surfaces and their bounds estimation

By introducing the homogenous coordinates, degree elevation formulas and combinatorial identities, also by using multiplication of Bernstein polynomials and identity transformation on equations, this paper presents some explicit formulas of the first and second derivatives of rational triangular Bézier surface with respect to each variable (including the mixed derivative) and derives some estimations of bound both on the direction and magnitude of the corresponding derivatives. All the results above have value not only in surface theory but also in practice.

GFFD： Generalized free-form deformation with scalar fields

The novel free-form deformation (FFD) technique presented in the paper uses scalar fields definedby skeletons with arbitrary topology. The technique embeds objects into the scalar field by assigning a field value to each point of the objects. When the space of the skeleton is changed, the distribution of the scalar field changes accordingly, which implicitly defines a deformation of the space. The generality of skeletons assures that the technique can freely define deformable regions to produce a broader range of shape deformations.

G^0 and G^1 connection between two adjacent B-spline surfaces

In this paper, the smooth connection between two B-spline surfaces is discussed. First, a brief proof of some simple sufficient conditions of Go and G1 continuity is given. On this basis, a novel method for Go or G1 connection between two adjacent B-spline surfaces is presented. A reparameterization step is firstly taken for one of the surfaces such that they have the same parameterization in v direction, then, adjust their boundary control vertices to make them Go or Gl connected. The GI connection parameter is determined by an optimization problem. Compared with the existed methods, our method is simple and easy to be used in practice.

A Platform for Collaborative Modeling

A collaborative virtual modeling environment based on VRML is presented as a sugarcane harvester modeling framework, and is illustrated with the implemented software that can using I;EAS, Smarteam, and Conceptual Innovation Design System （CIDS） as the supporting platform, which is powerful enough to meet the demands of different real life applications. It is possible to perform collaborative interactive modifications with concurrent synchronous visualization at each client computer with any required level of detail. The platform provides a product modeling and assembling environment, and the product data among I;EAS, Smarteam and CIDS can be exchanged.

Convexity-preserving interpolation of trigonometric polynomial curves with a shape parameter

In computer aided geometric design(CAGD) ,it is often needed to produce a convexity-preserving interpolating curve according to the given planar data points. However,most existing pertinent methods cannot generate convexity-preserving in-terpolating transcendental curves;even constructing convexity-preserving interpolating polynomial curves,it is required to solve a system of equations or recur to a complicated iterative process. The method developed in this paper overcomes the above draw-backs. The basic idea is:first to construct a kind of trigonometric polynomial curves with a shape parameter,and interpolating trigonometric polynomial parametric curves with C2(or G1) continuity can be automatically generated without having to solve any system of equations or do any iterative computation. Then,the convexity of the constructed curves can be guaranteed by the appropriate value of the shape parameter. Performing the method is easy and fast,and the curvature distribution of the resulting interpolating curves is always well-proportioned. Several numerical examples are shown to substantiate that our algorithm is not only correct but also usable.

Shape Control and Modification of Rational Bezier Curve and Surface

A Bezier interpolation approach is proposed which uses local generation of endpoint slopes and forces the curve and the surface to pass through an arbitrarily specified point to control and modify the shape of curve and surface, making the result satisfactory.

Applications of Power Rail Track Program to Tracings of Brazilian Railways

In Brazil, the use of software and applications in railway geometric designs is rare. Currently, after the division and privatization of the national rail network, the concessionaires who assumed the administration, are investing in modernization, recovery and extension of this transport model to make it more efficient. The PIL （Program of Investment in Logistics） has generated growth of the sector in response to the amount of investments, greatly enhancing the load capacity and optimizing the geometric design, which would allow speed of 80 km/h. Based on this information, the objective of this research is to verify the software applications of Power Rail Track Program of Bentley Systems, Inc. for geometric designs in future deployments of railways in Brazil. This software is based on numerical calculations, including roller adjustment by the least squares method to calculate and choose the best alignments, and regression tools, to a fast and effectively optimization of various parameters of the geometry for a future or existing railway. Different variables that allow you to optimize the geometric design are analyzed, considering several optional alignments and complex restrictions present in geometric design, taking into account variables such as circular curves, transition, tangents and rays. The software regression tools include curvature diagrams identifying points and curves, tangent and spirals. The analysis results are presented quickly and points can be added or deleted from the regression analysis, providing improved tracing. The software also allows to detail the elements of the executive project of the railway line such as rails, joints, turning points, waypoints and others. The result of this study has shown that the application of the Power Rail Track Program generates significant cost savings in time and increases in productivity, providing greater opportunity to optimize the geometry and reducing geometric design costs.

Implementation of an Available Parking Space Detection System in Hectic Parking Lots

Parking automation has been developed for locating available parking spaces inside a parking lot with new technologies, such as automatic collection, capacity, or empty spaces’ detection;to both reduce search time and avoid crowds of vehicles waiting to park in it. A simple detection system of available spaces, within the Faculty and Staff parking lot of the Engineering and Chemistry Departments at the Autonomous University of Chihuahua, Mexico (UACH), was set up. First, an analysis of vehicle capacity was carried out to establish the peak hours of vehicles’ entrances and compare it to the parking lots’ capacity. For one working week (6 days), it was determined that Tuesdays have the highest vehicle occupancy, and Saturdays are the days with the least traffic. Second, the geometric design of the parking lot (divided into two areas because of the terrain topography: upper and bottom levels), its dimensions and location of parking spots and marks on the pavement for traffic directions, were obtained from its blueprint, to visualize how the surveillance cameras can be oriented to cover the area. A detection system prototype was created for a specific area of the parking lot, using an artificial vision technique to perform the video extraction, while the digital image processing was developed in MATLAB. To complement and achieve the objective, Object- Oriented Programming (OOP) was used to obtain the count analysis as well as the availability/occupancy of each of the parking areas. This information is shown on a web page, with a simple driver-friendly design, since it has each parking space number and its availability in blue with the word “Available” or, in the opposite case, the word “Taken” in pink.

Comparison of Traffic Growth Factors in Three Major Highways of Bangladesh： A Case Study

The unanticipated increase in vehicle population and heavy axle loads has brought the road network of Bangladesh to a crumbling stage. The network is grossly short of its structural capacity, highly distressed and has started showing signs of premature failure. The RHD （Roads and Highways Department） of Bangladesh uses 8%-10% growth rate of traffic for structural design of these highways that need to be upgraded due to present high traffic volume demand. An attempt has been made through this case study, by using traffic flow data from different computerized toll plaza established in recent times, to predict traffic growth pattern of different highways of Bangladesh. The toll collectors of different computerized toll plaza have been recording and preserving round-the-year continuous flow data in a systematic manner. The study has taken this prospect of utilizing several years of flow data along Dhaka-Chittagong Highway （N-1）, Dhaka-Sylhet Highway （N-2）, Dhaka-North Bengal Highway （N-5） and found the traffic growth factor of 21.03%, 23.79% and 11.31%, respectively, which is much higher than that transport authority of Bangladesh is currently using. By the use of accurate traffic engineering parameters such as traffic growth factors, it is possible to resist frequent distress of pavement and sustainable pavement management can be implemented by RHD.

Improving the Efficiency of Mechatronic Systems in Order to Ensure Intensive Reform“Industry-4.0”

The presented work will show the highest relevance of solving all the issues related to this problem and present the results of the analysis of the main expected potential problems,which may occur in the implementation of the INDUSTRY-4.0 reform.It is proved that the pace and level of development of this reform will be determined to a large extent by the effectiveness of the individual nodes used and the entire mechatronic system.It has also been established that as a result of systematic miniaturization of the nodes of radio-electronic equipment and microelectronic equipment and microelectronic technology,the main problem of these reforms and the implementation of complex technological processes is instrumental and technological support,especially with cutting micro-tools and equipment.Therefore,on the example of these investigations,methods for improving their performance are shown.

REVERSE MODELING FOR CONIC BLENDING FEATURE

A novel method to extract conic blending feature in reverse engineering is presented. Different from the methods to recover constant and variable radius blends from unorganized points, it contains not only novel segmentation and feature recognition techniques, but also bias corrected technique to capture more reliable distribution of feature parameters along the spine curve. The segmentation depending on point classification separates the points in the conic blend region from the input point cloud. The available feature parameters of the cross-sectional curves are extracted with the processes of slicing point clouds with planes, conic curve fitting, and parameters estimation and compensation, The extracted parameters and its distribution laws are refined according to statistic theory such as regression analysis and hypothesis test. The proposed method can accurately capture the original design intentions and conveniently guide the reverse modeling process. Application examples are presented to verify the high precision and stability of the proposed method.

Parametric Selection and Continual Combination of Building Surface

A method to reparametrize G retional curve to obtain a C^1 curve is given. A practical G^1 continual connective between adjacent NURUS patches along common guadratic boundary curve is presented in this paper, and a specific algorithm for control points and weights of NURBS patches is discussed.