注塑模微机CAD系统

本文介绍了一个微机上运行的注塑模ＣＡＤ系统，此系统主要解决了四个难点，浇注系统设计，冷却系统分析，型腔，型芯的曲面造型设计，装配图和零件工作图的设计绘制，经厂家实际运用证明，该系统使用方便，结果正确，能提高设计效率，降低生产成本。     

Gate location design in injection molding of an automobile junction box with integral hinges

Polymers such as polypropylene or polyethylene offer a unique feature of producing an integral or living hinge for automobiles, which can flex over a million times without causing a failure. However, due to increased fluidity resistance at hinges during molding, several defects such as short shot or premature failure can occur with the improper selection of gate locations. In this paper, a design guideline was induced by investigating resin flow patterns depending on several gate positions obtained by numerical analyses of a simple strip with a hinge. The analyses of the simple strip part showed that the resin at the hinge did not flow until the other side of the strip was filled. Once the resin at the hinge did not flow for a long time enough to be solidified, defects such as short shots or hesitation marks formed. For a practical application of the design guideline determined, four gate systems for an automobile junction box were designed. It was found that the properly determined gate location leads to better resin flow and shorter hesitation time. Finally, injection molding tryouts using a mold that was designed by one of the proposed gate systems were conducted. The experiments showed that hinges without defects could be produced by using the designed gate location to assure the induced design guideline to be reasonable.     

Agustin de Betancourt's telegraph: Study and virtual reconstruction

The transmission of information has gone through various stages of evolution throughout its history. A stage before that of the electric telegraph was the so-called aerial/optical telegraph. It was developed towards the end of the 18th century and was in service until the middle of the 19th century. Chappe's system was widely used in France, and was the first to be in consistent use. However, a new and technologically superior system was developed soon afterwards which superseded it. Its inventor was Agustín de Betancourt, considered by some authors one of the founders of the Theory of Machines and Mechanisms, who, together with the distinguished clockmaker Breguet, presented it to the French Authorities in the turbulent decade of the 1790s.This article presents a historical review of this telegraph and analyzes its technical characteristics. It presents analytically, numerically and graphically some of the statements made about the telegraph, and corrects other subsequent observations. Lastly, a detailed reconstruction of the telegraph is made using different advanced CAD techniques, which provide an accurate static and dynamic view of each of its parts.     

Modeling on triangulations with geodesic curves

This paper discusses the problem of modeling on triangulated surfaces with geodesic curves. In the first part of the paper we define a new class of curves, called geodesic Bézier curves, that are suitable for modeling on manifold triangulations. As a natural generalization of Bézier curves, the new curves are as smooth as possible. In the second part we discuss the construction of C ⁰ and C ¹ piecewise Bézier splines. We also describe how to perform editing operations, such as trimming, using these curves. Special care is taken to achieve interactive rates for modeling tasks. The third part is devoted to the definition and study of convex sets on triangulated surfaces. We derive the convex hull property of geodesic Bézier curves.

A neural network-based approach for dynamic quality prediction in a plastic injection molding process

This paper presents an innovative neural network-based quality prediction system for a plastic injection molding process. A self-organizing map plus a back-propagation neural network (SOM-BPNN) model is proposed for creating a dynamic quality predictor. Three SOM-based dynamic extraction parameters with six manufacturing process parameters and one level of product quality were dedicated to training and testing the proposed system. In addition, Taguchi’s parameter design method was also applied to enhance the neural network performance. For comparison, an additional back-propagation neural network (BPNN) model was constructed for which six process parameters were used for training and testing. The training and testing data for the two models respectively consisted of 120 and 40 samples. Experimental results showed that such a SOM-BPNN-based model can accurately predict the product quality (weight) and can likely be used for various practical applications.     

从ASP的工作原理分析其安全性问题

该文通过分析ASP的工作原理,来阐述目前针对ASP的网络安全性问题。通过一个具体的实例,讲解了如何利用ASP的漏洞攻击服务器的过程,并对常见的安全性问题进行了介绍和归纳。希望通过实例的方式,让广大读者了解其攻击原理,并引起注意。在运用ASP编写程序时,避免安全性问题的发生,保证网站的运行和用户数据的安全性,为营造一个安全和谐的网络世界贡一点力量。     

SQL注入攻击原理及在数据库安全中的应用

SQL注入是根据网页的返回结果而获知网站的敏感信息。本文讨论了各种注入攻击技术的原理和特征,并给出了检测和防范的方法。     

Controller certification

A modern problem from aerospace control involves the certification of a large set of potential controllers with either a single plant or a fleet of potential plant systems, with both plants and controllers being MIMO and, for the moment, linear. Experiments on a limited number of controller/plant pairs should establish the stability and a certain level of margin of the complete set. We consider this certification problem for a set of controllers and provide algorithms for selecting an efficient subset for testing. This is done for a finite set of candidate controllers and, at least for SISO plants, for compact infinite set. In doing this, the ν-gap metric will be the main tool. Computational examples are given, including one of certification of an aircraft engine controller. The overarching aim is to introduce truly MIMO margin calculations and to understand their efficacy in certifying stability over a set of controllers and in replacing legacy single-loop gain and phase margin calculations.     

一种基于Web漏洞威胁模型的网站安全分析技术

网站日益受到黑客的青睐,针对Web应用程序的攻击事例屡见不鲜。如何全面、准确地分析网站面临的最大威胁成为专业信息安全公司和网站管理员的不可回避的难题。本论文借鉴攻击图的基本思想设计了漏洞威胁测试模型(VTTM),并以SQL注入漏洞为例对其进行建模,并利用两种算法分别计算了网站的最大威胁值及最优测试序列。     

注塑件缺陷诊断专家系统的研究及应用

本文建立了一个基于知识的注塑件缺陷诊断专家系统ＫＢＤＤＥＳ。该系统采用不精确推理及确定性理论,按人类专家处理问题的思维方式来协调各专家对问题假设的不确定性,并运用正反向混合推理的控制策略,对常见的注塑件缺陷及注射过程中的故障进行诊断,得出结论并给出避免缺陷或故障的方法及建议。系统知识的表达采用了“框架十规则”的复合表达技术,使不同层次的知识源统一于同一知识表达结构内。