Computation of four color irreducibility /

Vita.

Multiple color reflection in a single unit cell using double-layer electrochromic reaction

Multiple color states have been realized in single unit cell using double electrochromic (EC) reaction. The precise control of bistability in EC compounds which can maintain several colors on the two separated electrodes allows this new type of pixel to be realized. The specific electrical driving gives a way to maintain both sides in the reduced EC states and this colors overlapping in the vertical view direction can achieve the black state. The four color states (G, B, W, BK) in one cell/pixel can make a valuable progress to achieve a high quality color devices such like electronic paper, outdoor billboard, smart window and flexible display using external light source. © 2012 Optical Society of America.

链式可变形机器人的构形与运动研究

本文的研究内容围绕中国科学院创新基金和GUCAS-BHPB基金资助的项目“可变形机器人的研究”展开，其目的是研制具有较强环境适应能力和高机动性能的可变形移动机器人系统，为我国在灾难救援和特种作业等应用领域提供技术储备。论文首先对可变形机器人的研究现状进行了概述，接下来展开了三个方面的研究工作：平台方面，提出了一种新型可变形链式结构，并进行了结构设计和实验验证；构形方面，提出了基于相似理论的构形研究方法，对链式可变形机器人的构形设计和构形转化方法进行了研究；运动性能方面，通过理论和实验分析了链式可变形履带模块机器人不同构形的转向性能、越障性能和倾翻稳定性能等。各种用于非结构环境的移动机器人机构中，模仿生物蛇原型的链式机构由于具有多于确定空间位置和姿态所需的自由度，能够有效、迅速、可靠地响应许多复杂的作业任务，但是该类系统具有转向半径大和侧向稳定性差等缺点。在非结构环境中，机器人需要通过“以变应变”才能够应对复杂多变的任务和环境。因此，论文基于偏置关节的思想，提出了一种形态和结构均能够变化的新型链式结构。机器人的单个标准模块由模块本体、连接臂和偏置关节等组成。偏置关节避免了模块间的运动干涉，扩大了机器人模块间的相对运动空间。机器人模块的数量可以根据实际需要选择，机器人通过变形可以产生多种构形，同时每种构形又具有多种步态以适应作业任务的需要。根据变形机理，研制了链式可变形机器人样机，并对样机进行了相应的原理验证实验。链式可变形机器人构形的复杂性随着模块数量和构形数量的增加呈指数增长，增加了构形设计和构形控制的难度。针对构形设计和构形转化问题，本文基于相似理论，提出了构形研究的一般分析方法，并将其归纳成为：表达(Expression)、计数(Enumeration)、评价(Evaluation)和有效性(Efficiency)等四个方面的问题(简称“Four-E Problem”)。在构形设计方面，根据模块的物理结构和邻接关系提出了用构形矩阵来表达机器人结构的拓扑信息，并在仿真环境下进行有效的描述；提出了基于组合计数原理的递归算法用于多模块可变形机器人非同构构形的计数、枚举，并根据构形矩阵所表征的拓扑信息对构形进行评价；最后根据仿真结果，给出了可变形机器人的构形设计示例。在构形转化方面，论文利用图论中的基本思想和原理对机器人的构形和构形网络进行了建模，对构形转化的路径进行了计算，对构形转化的最佳路径和中心构形的选择进行了分析；以三模块可变形机器人的构形网络为例，证实了该方法的可行性。履带式移动机器人的运动能力涉及的问题很多，包括接地比压、驱动能力、地面阻力、启动特性、转向能力、越障能力、平顺性和倾翻稳定性等。本文主要研究链式可变形履带模块机器人不同构形的平面转向特性、系统越障性能和倾翻稳定性能等。论文首先对链式可变形履带模块机器人单模块(单履带)的接地比压分布进行了研究，并对接地比压的核心区域进行了分析。在复杂的环境中，机器人运动的路径多由弯曲的道路组成，转向性能是其改变运动方向的一种重要能力。转向形式通常有滑移转向和铰接转向两种，分别适用不同的构形。论文参照杨红旗模型和Kitano模型分别对链式可变形双模块机器人和链式可变形三模块机器人不同构形下的滑移转向和铰接转向进行了理论和实验分析。移动机器人的越障性能是机器人本体和环境相互作用时所产生的一种综合特性。论文分析了链式可变形机器人系统的斜坡爬行性能、沟壑爬行性能、楼梯爬行性能和倾翻稳定性能。考虑到城市环境中，楼梯是最为典型的障碍物之一，论文重点对履带式移动机器人在踢面爬升、踢面翻越和坡度线爬行等阶段的运动条件、运动性能和影响因素进行了分析。在非结构环境中，大多数情况是坎坷不平的地面和复杂的三维地形，机器人的倾翻稳定性(或者说是抗倾翻能力)非常重要。根据Iagnemma和Papadopoulos提出的稳定性分析方法，定义机器人的倾翻稳定锥，对履带式可变形机器人变形过程中的倾翻稳定性进行了综合判定，同时通过仿真比较了机器人三种对称构形在仰俯、倾斜和偏转等组合干扰下的倾翻稳定性。稳定锥方法，为可变形机器人的倾翻问题提供了有效的理论分析手段，同时稳定锥方法还可以适用于其它轮式或腿式移动机器人的稳定性分析。理论分析和实验表明，本文研制的履带驱动链式可变形机器人平台，具有多种构形和步态以适应不同的环境和任务，具有废墟、砾石、草地、沙地、楼梯、坡度和管道等城市或野外环境的通过能力。可变形机器人机构灵巧、结构紧凑、便于携带，它不仅能够用于救援、消防、公安和环保等领域，在星球探测、国防安全等方面也有着潜在的应用前景。

A Binocular, Foveated Active Vision System

This report documents the design and implementation of a binocular, foveated active vision system as part of the Cog project at the MIT Artificial Intelligence Laboratory. The active vision system features a three degree of freedom mechanical platform that supports four color cameras, a motion control system, and a parallel network of digital signal processors for image processing. To demonstrate the capabilities of the system, we present results from four sample visual-motor tasks.

Analyse du raisonnement covariationnel favorisant le passage de la fonction à la dérivée et des situations qui en sollicitent le déploiement chez des élèves de 15 à 18 ans

Afin de mieux cerner les enjeux de la transition entre le secondaire et le postsecondaire, nous proposons un examen du passage de la notion de fonction à celle de dérivée. À la lumière de plusieurs travaux mettant en évidence des difficultés inhérentes à ce passage, et nous basant sur les recherches de Carlson et ses collègues (Carlson, 2002; Carlson, Jacobs, Coe, Larsen et Hsu, 2002; Carlson, Larsen et Jacobs, 2001; Oehrtman, Carlson et Thompson, 2008) sur le raisonnement covariationnel, nous présentons une analyse de la dynamique du développement de ce raisonnement chez des petits groupes d’élèves de la fin du secondaire et du début du collégial dans quatre situations-problèmes différentes. L’analyse des raisonnements de ces groupes d’élèves nous a permis, d’une part, de raffiner la grille proposée par Carlson en mettant en évidence, non seulement des unités de processus de modélisation (ou unités de raisonnement) mises en action par ces élèves lors des activités proposées, mais aussi leurs rôles au sein de la dynamique du raisonnement. D’autre part, cette analyse révèle l’influence de certaines caractéristiques des situations sur les interactions non linéaires entre ces unités.

Irregular satellites of Jupiter: capture configurations of binary-asteroids

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Collisions with the Earth: the Moon's contribution

In the present work is analyzed the contribution of the Moon on the collisional process of the Earth with asteroids (NEOs). The dynamical system adopted is the restricted four-body problem Sun-Earth-Moon-particle. Using a simple analytical approach one can verify that, the orbit of an object can be significantly affected by the Moon's gravitational field when their relative velocity is smaller than 5 km/s. Therefore, the present work is based on hypothetical asteroids whose velocities relative to Moon are of the order of 1 km/s. In fact, there are several real objects (NEOs) with such velocities at the point they cross the Earth's orbit. The net results obtained indicate that the Moon helps to avoid collisions (2.6%) more than it contributes to extra collisions (0.6%). (C) 2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

Alternative paths to Earth-Moon transfer

The planar, circular, restricted three-body problem predicts the existence of periodic orbits around the Lagrangian equilibrium point L1. Considering the Earth-lunar-probe system, some of these orbits pass very close to the surfaces of the Earth and the Moon. These characteristics make it possible for these orbits, in spite of their instability, to be used in transfer maneuvers between Earth and lunar parking orbits. The main goal of this paper is to explore this scenario, adopting a more complex and realistic dynamical system, the four-body problem Sun-Earth-Moon-probe. We defined and investigated a set of paths, derived from the orbits around L1, which are capable of achieving transfer between low-altitude Earth (LEO) and lunar orbits, including high-inclination lunar orbits, at a low cost and with flight time between 13 and 15 days.

Strategies for plane change of Earth orbits using lunar gravity and derived trajectories of family G

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo numérico da captura gravitacional temporária utilizando o problema de quatro corpos

Pós-graduação em Física - FEG

Natural formations at the Earth-Moon triangular point in perturbed restricted problems

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

EC03-1892 Identifying Soybean Rust

This four-color extension circular identifies the different diseases of soybeans: soybean rust, bacterial blight, bacterial pustle, and downy mildew. It also shows diseases that are similar looking: Cercospora blight, Frogeye leaf spot and brown spot. It also discusses what to look for when scouting for soybean rust.

Automated parallel DNA sequencing on multiple channel microchips

We report automated DNA sequencing in 16-channel microchips. A microchip prefilled with sieving matrix is aligned on a heating plate affixed to a movable platform. Samples are loaded into sample reservoirs by using an eight-tip pipetting device, and the chip is docked with an array of electrodes in the focal plane of a four-color scanning detection system. Under computer control, high voltage is applied to the appropriate reservoirs in a programmed sequence that injects and separates the DNA samples. An integrated four-color confocal fluorescent detector automatically scans all 16 channels. The system routinely yields more than 450 bases in 15 min in all 16 channels. In the best case using an automated base-calling program, 543 bases have been called at an accuracy of >99%. Separations, including automated chip loading and sample injection, normally are completed in less than 18 min. The advantages of DNA sequencing on capillary electrophoresis chips include uniform signal intensity and tolerance of high DNA template concentration. To understand the fundamentals of these unique features we developed a theoretical treatment of cross-channel chip injection that we call the differential concentration effect. We present experimental evidence consistent with the predictions of the theory.