A questioning based method to automatically acquire expert assembly diagnostic knowledge

In the domain of manual mechanical assembly, expert knowledge is an important means of supporting assembly planning that leads to fewer issues during actual assembly. Knowledge based systems can be used to provide assembly planners with expert knowledge as advice. However, acquisition of knowledge remains a difficult task to automate, while manual acquisition is tedious, time-consuming, and requires engagement of knowledge engineers with specialist knowledge to understand and translate expert knowledge. This paper describes the development, implementation and preliminary evaluation of a method that asks a series of questions to an expert, so as to automatically acquire necessary diagnostic and remedial knowledge as rules for use in a knowledge based system for advising assembly planners diagnose and resolve issues. The method, called a questioning procedure, organizes its questions around an assembly situation which it presents to the expert as the context, and adapts its questions based on the answers it receives from the expert. (C) 2014 Elsevier Ltd. All rights reserved.

A Short-Channel Common Double-Gate MOSFET Model Adapted to Gate Oxide Thickness Asymmetry

Existing compact models for common double-gate (CDG) MOSFETs are based on the fundamental assumption of having symmetric gate oxide thickness. In this paper, we demonstrate that using the unique quasi-linear relationship between the surface potentials, it is possible to develop compact model for CDG-MOSFETs without such approximation while preserving the mathematical complexity at the same level of the existing models. In the proposed model, the surface potential relationship is used to include the drain-induced barrier lowering, channel length modulation, velocity saturation, and quantum mechanical effect in the long-channel model and good agreement is observed with the technology computer aided design simulation results.

Efficient simulation and rendering of realistic motion of one-dimensional flexible objects

In gross motion of flexible one-dimensional (1D) objects such as cables, ropes, chains, ribbons and hair, the assumption of constant length is realistic and reasonable. The motion of the object also appears more natural if the motion or disturbance given at one end attenuates along the length of the object. In an earlier work, variational calculus was used to derive natural and length-preserving transformation of planar and spatial curves and implemented for flexible 1D objects discretized with a large number of straight segments. This paper proposes a novel idea to reduce computational effort and enable real-time and realistic simulation of the motion of flexible 1D objects. The key idea is to represent the flexible 1D object as a spline and move the underlying control polygon with much smaller number of segments. To preserve the length of the curve to within a prescribed tolerance as the control polygon is moved, the control polygon is adaptively modified by subdivision and merging. New theoretical results relating the length of the curve and the angle between the adjacent segments of the control polygon are derived for quadratic and cubic splines. Depending on the prescribed tolerance on length error, the theoretical results are used to obtain threshold angles for subdivision and merging. Simulation results for arbitrarily chosen planar and spatial curves whose one end is subjected to generic input motions are provided to illustrate the approach. (C) 2016 Elsevier Ltd. All rights reserved.

Detección de límites arquitectónicos en edificios históricos combinando imágenes digitales con nubes de puntos

[ES] El proyecto estudia algoritmos de detección de bordes aplicados a imágenes fotográficas y procedentes de nubes de puntos, posteriormente combina los resultados y analiza las posibilidades de mejora de la solución conjunta.

Diseño, Modelado y Análisis por Elementos Finitos de un Cuadro de Bicicleta de Carretera.

[ES]El objetivo de este proyecto es llevar a cabo el diseño conceptual, modelado y análisis estructural de un cuadro de bicicleta de geometría de carretera, empleando herramientas de Diseño Asistido por Ordenador y software de Análisis con Elementos Finitos. El modelo inicial será analizado y optimizado de cara a que cumpla los requerimientos resitentes del escenario de cargas asumido. El propósito de este proyecto es completar la primera fase de un hipotético caso de producción.

Evaluation and modeling of lanthanum diffusion in TiN/La 2O 3/HfSiON/SiO 2/Si high-k stacks

In this study, TiN/La 2O 3/HfSiON/SiO 2/Si gate stacks with thick high-k (HK) and thick pedestal oxide were used. Samples were annealed at different temperatures and times in order to characterize in detail the interaction mechanisms between La and the gate stack layers. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) measurements performed on these samples show a time diffusion saturation of La in the high-k insulator, indicating an La front immobilization due to LaSiO formation at the high-k/interfacial layer. Based on the SIMS data, a technology computer aided design (TCAD) diffusion model including La time diffusion saturation effect was developed. © 2012 American Institute of Physics.

嵌入式DSP系统中SDF模型的层次化存储优化方法

在同步数据流模型(SDF)描述的嵌入式数字信号处理(DSP)系统中,计算体单一出现调度(SAS)算法对于存在反馈环和数据密集处理的应用不可解或内存优化效果很差.文中提出了将SAS和Non-SAS类型调度算法相结合的层次化的存储优化方法,定义了数据密集分量和强连通分量来描述环和数据密集处理结构,并依据数据优先消耗原则设计了启发式的Non-SAS调度算法对分量进行存储优化.该方法适用于任意SDF模型,并有良好的存储优化效果.实验结果证明了其有效性.

基于知识重用的针织服装工艺快速设计系统

目前针织服装设计领域面临着日益加剧的市场竞争，传统的基于手工设计的研发模式已不能适应当前多品种、小批量、交货期短的市场需求。传统的计算机辅助设计软件（Computer Aided Design, 简称CAD）在服装行业得到广泛应用，但效果与期望值相差较远。传统设计软件多关注于设计结果的表达与重用，对于设计过程中的计算知识重用机制缺乏有效的支持；另外这些设计软件大多基于传统的WIMP范式的菜单或命令行交互方式，不符合人们用纸笔勾画的习惯，不利于计算机操作水平普遍较低的服装行业从业人员的使用。本文拟基于知识重用的设计思想，将笔交互技术引入到传统针织服装工艺设计过程中，设计并实现一个基于知识重用的针织服装工艺快速设计系统，进而提高服装设计的效率。 论文主要研究内容包括： （1）通过分析传统针织服装工艺设计过程特点，提出了基于知识重用的针织服装工艺快速设计过程模型，并分析了该过程模型的特点，建立了系统业务流程和系统框架； （2）针对设计案例形状知识的重用，研究了形状知识的表达和提取方法，针对典型款式的针织服装设计，提出了设计轮廓图的实例化算法实现了尺寸驱动功能，提出了基于草图相似度的设计案例推荐技术，该推荐技术分别采用特征点匹配和形状匹配实现了设计案例的推荐； （3）针对设计案例计算知识的重用，研究了计算知识的表达方法，设计了面向计算知识编辑的基于手势的笔式用户界面，改进了传统Radial布局算法对计算知识进行可视化呈现，以辅助设计者对计算知识的理解和编辑； （4）在上述研究的基础上，设计并实现了一个基于知识重用的针织服装工艺快速设计系统，经过实验评估，该系统相比于传统的CAD软件能显著提高设计效率。

计算机辅助带时延多变量系统的离散控制设计

本文将Smith预估技术与逆 Nyquist 阵列法结合对多时延多变量对象进行离散控制系统设计,采用这种方法设计出的控制器易用计算机实现,系统仿真结果也是令人满意的。

快速成型技术中分层算法的研究与进展

根据对零件制造精度和效率的关注程度的不同,开发出了多种分层算法。在同等加工时间的情况下,根据加工精度的不同,将这些分层算法分为等层厚分层算法和适应性分层算法两类。通过对STL模型、原始CAD模型和点云数据的分析,讨论了两类分层算法的研究和发展,然后介绍了斜边分层算法和曲面分层算法等先进分层算法的原理和成果,最后讨论了快速成型分层算法的研究方向和趋势。

基于点集曲面投影算法的自由曲面匹配

测量数据的精确定位是实现复杂曲面加工检测的关键,针对测量点云数据与NURBS表示的CAD自由曲面模型匹配中求最近点计算方面存在的问题,提出了一种简单、有效的寻找最近点的方法。该方法与由测量点集评估给定曲面上的最近点的传统算法相反,采用点集曲面(point set surface,PSS)投影算法,对给定自由曲面模型上有限个点与不附加任何几何和拓扑信息的散乱点集之间进行粗匹配获得初始位置,进而以最近点迭代算法(ICP)完成测量数据定位的精确调整,达到全局及局部最优的目标。实验结果表明,采用PSS投影算法法寻找最近点不仅效率高,而且能得到全局匹配结果,可以为精匹配提供较好的计算初值,减少了ICP算法进行二次匹配时,迭代次数及执行时间并且精度得到了较大提高。

Client-based Logging: A New Paradigm of Distributed Transaction Management

The proliferation of inexpensive workstations and networks has created a new era in distributed computing. At the same time, non-traditional applications such as computer-aided design (CAD), computer-aided software engineering (CASE), geographic-information systems (GIS), and office-information systems (OIS) have placed increased demands for high-performance transaction processing on database systems. The combination of these factors gives rise to significant challenges in the design of modern database systems. In this thesis, we propose novel techniques whose aim is to improve the performance and scalability of these new database systems. These techniques exploit client resources through client-based transaction management. Client-based transaction management is realized by providing logging facilities locally even when data is shared in a global environment. This thesis presents several recovery algorithms which utilize client disks for storing recovery related information (i.e., log records). Our algorithms work with both coarse and fine-granularity locking and they do not require the merging of client logs at any time. Moreover, our algorithms support fine-granularity locking with multiple clients permitted to concurrently update different portions of the same database page. The database state is recovered correctly when there is a complex crash as well as when the updates performed by different clients on a page are not present on the disk version of the page, even though some of the updating transactions have committed. This thesis also presents the implementation of the proposed algorithms in a memory-mapped storage manager as well as a detailed performance study of these algorithms using the OO1 database benchmark. The performance results show that client-based logging is superior to traditional server-based logging. This is because client-based logging is an effective way to reduce dependencies on server CPU and disk resources and, thus, prevents the server from becoming a performance bottleneck as quickly when the number of clients accessing the database increases.

Slow light with a swept-frequency source.

ct: We introduce a new concept for stimulated-Brillouin-scattering-based slow light in optical fibers that is applicable for broadly-tunable frequency-swept sources. It allows slow light to be achieved, in principle, over the entire transparency window of the optical fiber. We demonstrate a slow light delay of 10 ns at 1.55 μm using a 10-m-long photonic crystal fiber with a source sweep rate of 400 MHz/μs and a pump power of 200 mW. We also show that there exists a maximal delay obtainable by this method, which is set by the SBS threshold, independent of sweep rate. For our fiber with optimum length, this maximum delay is ~38 ns, obtained for a pump power of 760 mW.

High-fidelity, broadband stimulated-Brillouin-scattering-based slow light using fast noise modulation.

We demonstrate a 5-GHz-broadband tunable slow-light device based on stimulated Brillouin scattering in a standard highly-nonlinear optical fiber pumped by a noise-current-modulated laser beam. The noisemodulation waveform uses an optimized pseudo-random distribution of the laser drive voltage to obtain an optimal flat-topped gain profile, which minimizes the pulse distortion and maximizes pulse delay for a given pump power. In comparison with a previous slow-modulation method, eye-diagram and signal-to-noise ratio (SNR) analysis show that this broadband slow-light technique significantly increases the fidelity of a delayed data sequence, while maintaining the delay performance. A fractional delay of 0.81 with a SNR of 5.2 is achieved at the pump power of 350 mW using a 2-km-long highly nonlinear fiber with the fast noise-modulation method, demonstrating a 50% increase in eye-opening and a 36% increase in SNR in the comparison.

Error recovery in cyberphysical digital microfluidic biochips

Droplet-based digital microfluidics technology has now come of age, and software-controlled biochips for healthcare applications are starting to emerge. However, today's digital microfluidic biochips suffer from the drawback that there is no feedback to the control software from the underlying hardware platform. Due to the lack of precision inherent in biochemical experiments, errors are likely during droplet manipulation; error recovery based on the repetition of experiments leads to wastage of expensive reagents and hard-to-prepare samples. By exploiting recent advances in the integration of optical detectors (sensors) into a digital microfluidics biochip, we present a physical-aware system reconfiguration technique that uses sensor data at intermediate checkpoints to dynamically reconfigure the biochip. A cyberphysical resynthesis technique is used to recompute electrode-actuation sequences, thereby deriving new schedules, module placement, and droplet routing pathways, with minimum impact on the time-to-response. © 2012 IEEE.