美国星基增强系统发展现状和未来

本文介绍了星基增强系统产生的背景以及美国的星基增强系统WAAS（广域增强系统）的系统架构,回顾了WAAS（广域增强系统）的发展历史,分析了WAAS（广域增强系统）的发展现状和未来的发展方向。     

A use of case-based reasoning technique in building expert systems

Matra Marconi Space France and Aramiihs (Action de Recherche et Application Matra Irit en Interaction Homme Système) laboratory have used and evaluated Case Based Reasoning (CBR) techniques in two projects:

• - The first project is about the development of a system dedicated to help satellites AIT/AIV (Assembly Integration and Test/Validation) test engineers to cope with incidents occurring during test activities. The project is funded by the EGSE System Section of ESTEC (European Space Research and Technology Centre.).

• - The second project is related to the building of a knowledge-based system for diagnosis assistance in AIT/AIV activities of Ariane4 Vehicle Equipment Bay (VEB). The project is financed by internal funding of MMS-F.

In the two projects, CBR technique is neither used the same way nor with the same purpose.

In the first project, CBR technique is used to find out or suggest the cause of an anomaly when an incident appears. Confronted with the occurrence of an incident, the system will refer to its characteristics (test context, symptoms…) that are considered as relevant to retrieve previous similar incidents.

In the second project, CBR technique is combined with Rule Based Reasoning and Model Based Reasoning ones to form the reasoning core of a Hybrid Knowledge Based System. When an incident occurs, the system proposes to test engineers a diagnosis approach based on the combination of different knowledge (coded into rule, cases and models).

Aramiihs is a research unit where engineers from MMS and researchers from the IRIT (Institut de Recherche en Informatique de Toulouse) CNRS (Centre National de la Recherche Scientifique) collaborate on problems concerning new types of man-system interaction.     

Simulation of the Crashing of Sandwich Structures under Impact Loads by Movable Cellular Automata

Movable cellular automata (MCA) method is applied in the analysis of dynamic characters of ceramic armor composite structures under impact loading. As a new approach, MCA is different from the traditional numerical methods such as the finite element method and boundary element method. Based on the theory of particle mechanics, MCA is applied as a powerful tool in relying specific structural analysis of materials loss and penetrating damages. In this paper the method is used to study responses of multi-layered ceramic plates as a base of armor structures under impact loading, thus assisting further investigations in the crashing process and to improve ceramic armor structures.     

网络被动测量方法

网络测量方法主要分为主动测量和被动测量，本文主要介绍了被动测量方法及其实现。     

新技术的应用及其对DCS的影响

简要介绍了ＤＣＳ的一般特点及传统ＤＣＳ存在的不足，着重分析了现场总线、ＯＰＣ标准、Ｉｎｔｅｒｎｅｔ及ＷｉｎｄｏｗｓＮＴ等新技术对ＤＣＳ发展的影响，指出这些新技术的应用必将使ＤＣＳ的控制功能更加完善。     

Vector Fields: an Interactive Tool for Animation, Modeling and Simulation with Physically Based 3D Particle Systems and Soft Objects

Vectorfields have traditionally been used in computer graphics as a means of visualizing models over time. This paper presents a system which extends the use of vector fields as an interactive tool for physically based three dimensional particle systems and soft objects. The techniques implemented in the system provide the user with new flexibility in animation, modeling and simulation. This paper describes bounded interactive vectorfields and how they can be used to manipulate particle systems and a class of soft objects. Applications to animation, modeling and simulation are also presented.     

基于ATP-ABE的访问控制方案

对访问控制机制中存在的安全性和有效性的问题进行了研究，提出了基于访问树剪枝的属性加密ATP-ABE（Access Tree Pruning Attribute Based Encryption）的访问控制方案。当ATP-ABE算法需要访问它的树型结构访问策略时，通过剪枝处理访问树结构中包含用户ID属性节点的分支，提高了用户所有者DO（Data Owner）管理和控制属性的效率，更加有效地实现了数据共享。还为访问树结构设计了许可访问属性，使DO仍保留共享数据的关键属性，并且能够完全控制它们的共享数据。基于决策双线性密钥交换算法DBDH（Decisional Bilinear Diffie-Hellman）假设分析了ATP-ABE方案的安全性，研究结果表明与两种经典ABE方案比较，ATP-ABE更加有效地减少了算法的系统设置、私钥生成、密文大小、用户属性撤销以及加解密过程中的计算开销，并给出了定量结论。     

Designing like a Pro: The automated composition of workflow activities

To design a workflow process that is efficient, meaningful, and understandable it is important to properly consider how to compose the activities it will consist of. In this paper, guidelines are presented for this exact purpose. These focus on the elementary data-processing steps that are at the core of a workflow process. The guidelines help to determine the relative importance of these data-processing steps as well as their relatedness, such that activities can be composed in a fully automated manner. We implemented this approach in freely available software. A thorough evaluation that incorporates real-life workflow designs indicates that the use of these guidelines leads to activities that closely resemble those designed by experienced modelers. As such, the proposed guidelines provide a proper and automated alternative to what is otherwise a complex and time-consuming task.     

Controllable Image‐Based Transfer of Flow Phenomena

Modelling flow phenomena and their related weathering effects is often cumbersome due their dependence on the environment, materials and geometric properties of objects in the scene. Example‐based modelling provides many advantages for reproducing real textures, but little effort has been devoted to reproducing and transferring complex phenomena. In order to produce realistic flow effects, it is possible to take advantage of the widespread availability of flow images on the Internet, which can be used to gather key information about the flow. In this paper, we present a technique that allows the transfer of flow phenomena between photographs, adapting the flow to the target image and giving the user flexibility and control through specifically tailored parameters. This is done through two types of control curves: a fitted theoretical curve to control the mass of deposited material, and an extended colour map for properly adapting to the target appearance. In addition, our method filters and warps the input flow in order to account for the geometric details of the target surface. This leads to a fast and intuitive approach to easily transfer phenomena between images, providing a set of simple and intuitive parameters to control the process.     

Engineering knowledge formalization and proposition for informatics development towards a CAD-integrated DfX system for product design

Target design methodologies (DfX) were developed to cope with specific engineering design issues such as cost-effectiveness, manufacturability, assemblability, maintainability, among others. However, DfX methodologies are undergoing the lack of real integration with 3D CAD systems. Their principles are currently applied downstream of the 3D modelling by following the well-known rules available from the literature and engineers’ know-how (tacit internal knowledge).This paper provides a method to formalize complex DfX engineering knowledge into explicit knowledge that can be reused for Advanced Engineering Informatics to aid designers and engineers in developing mechanical products. This research work wants to define a general method (ontology) able to couple DfX design guidelines (engineering knowledge) with geometrical product features of a product 3D model (engineering parametric data). A common layer for all DfX methods (horizontal) and dedicated layers for each DfX method (vertical) allow creating the suitable ontology for the systematic collection of the DfX rules considering each target. Moreover, the proposed framework is the first step for developing (future work) a software tool to assist engineers and designers during product development (3D CAD modelling).A design for assembly (DfA) case study shows how to collect assembly rules in the given framework. It demonstrates the applicability of the CAD-integrated DfX system in the mechanical design of a jig-crane. Several benefits are recognized: (i) systematic collection of DfA rules for informatics development, (ii) identification of assembly issues in the product development process, and (iii) reduction of effort and time during the design review.