Identification and optimization of key process parameters in noncontact laser scanning for reverse engineering

This Extended Technical Note shows that the final accuracy level of reverse engineered surfaces depends on scanning distance and scanning angle of the laser beam, hence it also depends on the morphology of the scanned objects. On scanning strongly curved objects, such as the ones with free form surfaces, the distance and impact angle of the laser beam are changing continuously during the scanning process. On the basis of these, two critical parameters are specified for the design model, which make it possible to predict these two factors in advance, depending on the morphology of the scanned object. First, a mathematical-statistical design model of the scanning process is generated, which relies on ANOVA (analysis of variance) and DOE (design of experiments). In the next step, a fitness function is optimized by the genetic algorithm (GA) program. This optimization improves the accuracy of the final scanned surfaces, in terms of the minimum standard deviation values of reverse engineered 3D surface model. The proposed approach was confirmed in a case study, which is presented at the end of this Technical Note.     

基于Delaunay图的反向最近邻查询

将查询点作为Delaunay图的一个生成点,利用Delaunay图的生成点与其邻接生成点之间的关系,在查询点的邻接生成点集(元素个数小于等于6)中计算数据集中给定点的反向最近邻。把伴随Delaunay图增量生成过程产生的Delaunay树作为查询索引结构,该结构能存储Delaunay图,在数据点插入和删除时维护Delaunay图的拓扑结构。     

Available-to-promise based bidding decision by fuzzy mathematical programming and genetic algorithm

The present study attempts to integrate bidding decisions with order promising and production planning to enhance supplier profitability and service level. This study formulates the bid price and production plan as a mixed integer programming model with fuzzy constraints. The fuzzy constraints represent the decision-maker’s subjective judgment regarding the customer’s price tolerance. The proposed model combines the advanced available-to-promise (AATP) concept to find optimum resource allocation and enable accurate estimations of production costs and delivery dates. The proposed solution procedure determines the optimum bid price by striking a compromise between profitability and the possibility to win the contract. This study develops a genetic algorithm to solve this problem, and provides computer simulated experiments to evaluate the performance of the proposed approach.     

Theory and methodology on the global optimal solution to a General Reverse Logistics Inventory Model for deteriorating items and time-varying rates

In this paper, we present a unified general inventory model for integrated production of new items and remanufacturing of returned items for an infinite planning horizon. Our model considers a production environment that consists of three shops. The first shop is for remanufacturing returned items, the second shop is for manufacturing new items, while the third shop is for collecting returned items to be remanufactured in the first shop. The system is subject to joint production and remanufacturing options, the first one is to produce new items while the second one is to reproduce/recycle the returned items “as-good-as new”. Items deteriorate while they are in storage, and production, remanufacturing, demand, return, and deterioration rates are arbitrary functions of time. A closed form for the total relevant costs as well as a rigorous mathematical proof, which shows the global optimality of the solution to the underlying inventory system are introduced. Illustrative examples, which explain the application of the theoretical results as well as their numerical verifications, are also given.     

Portfolios of buyer–supplier exchange relationships in an online marketplace for IT services

Most studies on the role of IT for economic exchange predicted that under a given set of exchange attributes buyers would choose a certain mode of relationship with suppliers. Our study of an online IT services marketplace revealed that buyers do not have a single, uniformly preferred type of relationship, but rather maintain a portfolio of relationships. Furthermore, different buyers arrange their portfolios of exchange relationships in different ways. We found four clusters of buyers' portfolios of relationships labeled Transactional buyers, Recurrent buyers, Small diversifiers and Large diversifiers, that differ in their usage of auction or negotiation mechanism, their supplier relations as well as their usage of preferred suppliers. Our results thus paint a richer picture of how buyers organize their supplier networks online.     

An algorithmic framework for network reconstruction

Models of biological systems and phenomena are of high scientific interest and practical relevance, but not always easy to obtain due to their inherent complexity. To gain the required insight, experimental data are provided and need to be interpreted in terms of models that explain the observed phenomena. In systems biology the framework of Petri nets is often used to describe models for the regulatory mechanisms of biological systems. The aim of this paper is to provide, based on results in Marwan et al. (2008) [1] and Durzinsky et al. (2008) [2], an algorithmic framework for the challenging task of generating all possible Petri nets fitting the given experimental data.     

基于PLC变频控制系统在反渗透海水淡化装置中的应用

介绍了以西门子S72400为核心的变频控制系统在反渗透海水淡化装置中的应用,给出了控制系统的工作原理、硬件集成和软件设计方法。     

A Computer Vision Method for 3D Reconstruction of Curves-Marked Free-Form Surfaces

Visual method is now broadly used in reverse engineering for 3D reconstruction. The traditional computer vision methods are feature-based, i.e., they require that the objects must reveal features owing to geometry or textures. For textureless free-form surfaces, dense feature points are added artificially. In this paper, a new method is put forward combining computer vision with CAGD. The surface is subdivided into N-side Gregory patches using marked curves, and a stereo algorithm is used to reconstruct the curves. Then, the cross boundary tangent vector is computed through reflectance analysis. At last, the whole surface can be reconstructed by jointing these patches with 1Gcontinuity.     

逆向工程中复杂拓扑关系的三角网格构造*

三角网格构造是逆向工程CAD建模技术中的一个重要步骤。提出了一种针对扫描线点云数据的三角网格构造方法,该方法的核心思想是合并同层的扫描线,并且标记合并后扫描线的间断点,以便三角网格构造和拓扑结构建立。该方法解决了对于包含分叉和内孔特征的三角网格的构造问题。     

基于语义层行为结构的变换对形式化格局识别技术的再探究*

程序的语义层是程序的词法层和语法层的抽象表达,而蕴涵在软件中的语义层构成了人脑思维与机器思维交互过程的中间变换,从程序的语义层出发,利用行为结构的高层表达进行软件理解,进而抽取设计决策,成为了软件逆向工程理论研究的热门课题,形式化格局识别技术在不同程度上表达了上述思想。基于以上分析,对格局识别技术作进一步探究,并在原有基础上提出了新的改进算法与实施技术。