基于物理的人体空中运动仿真

根据给定的处于关键时刻的人体关键姿态,运用优化方法生成满足牛顿力学的人体运动是人体运动仿真研究的重要问题.由于牛顿力学的强非线性和数值优化方法只能找到局部最优解,将牛顿力学约束直接作为约束条件的优化模型在实践中的收敛性不好.通过将牛顿力学约束转化为目标函数,同时增加对关键时刻的优化,提高了模型的收敛性,使其不依赖于被仿真运动的类型、人体质量参数和关键时刻准确程度等因素.仿真出来的人体运动尽可能地满足了牛顿力学.通过仿真7类复杂的蹦床运动验证了新模型的有效性,同时还将该模型用于人体受力分析和体育运动的新动作设计.     

Robust periodically time‐varying horizon finite memory fault detection filter design for polytopic uncertain discrete‐time systems

In this paper, a robust periodically time‐varying horizon finite memory fault detection filter (PTVHFM‐FDF) is proposed to generate residual signal for the purpose of system monitoring. The major advantage of PTVHFM‐FDF is that finite historical data can be sufficiently utilized to enhance the robustness of fault detection against model uncertainty and external disturbance. The analysis, design, and application of PTVHFM‐FDF consist of several steps. Firstly, a periodic time‐varying residual error system is constructed on the basis of augmented method and time domain partition method. Secondly, in facilitating robust stability and performance analysis, the time‐varying residual error system is further transformed into a polyhedral time‐invariant system on the basis of time lifting technique. Thirdly, less conservative PTVHFM‐FDF analysis and design conditions are then obtained on the basis of Finsler relaxation lemma and slack variable structure definition. Fourthly, choices of memory window horizon parameters are properly suggested on the basis of a compromise between FDF robustness and its structural complexity. Finally, an integrated design and application algorithm of PTVHFM‐FDF is summarized. Effectiveness of PTVHFM‐FDF is verified through three examples. Copyright © 2017 John Wiley & Sons, Ltd.     

高职模具类人才培养新模式的研究与实践

为了解决传统教学无法全面培养人才的问题,采用"课程融合+时空耦合+过程结合"的方式开展人才培养研究。以注射模设计与制造生产过程为导向,构建大项目牵引下的跨越课程、跨越学期的课程融合新模式,利用信息通信技术及互联网平台,将互联网与传统教学进行深度融合,创造新的教学生态,构建多元多维互动的时空耦合教学新关系,以全方位评价为引导,构建课程多元多维的评价新机制。以3个班级为对象开展不同模式下的教学,对试验班级成绩进行分析,研究结果表明:课程融合+时空耦合+过程结合新模式培养的学生更好地完成了综合项目,获得了较好的教学效果。     

狭义相对论与超光速运动

近来年,王力军等利用增益线性反常色散,证明了激光脉冲在铯原子气中的超光速传递;激光脉冲在此区域以超过光速c甚至负的群速传递,而脉冲的外形无改变.以往课本上说,没有任何东西,包括光本身的传递能快于光.新的实验表明它不再正确.研究表明,如果人们相信超光速运动可能存在,那么按照爱恩斯坦的方法,利用芬斯勒时空ds4=gijkldxidxjdxkdxl取代通常的闵柯夫斯基时空,我们可以得到新的时空变换.基于新变换的讨论不仅可保留Einstein狭义相对论的全部内容而且包容超光速运动.     

喷锚(土钉)技术在翻车机室基坑支护中的应用

根据深基坑复杂地质层的工程特性,结合铜陵电厂五期扩建工程翻车机室实际工程,简要介绍喷锚网支护技术的基本原理,支护设计技术及工程效果,并对施工中一些技术问题进行思考,以期不断提高设计水平、改进施工方法,尽可能地为类似工程提供借鉴.     

Deneubourg模型的球对称含时结构

应用分岐理论，求出了在Ｄｉｒｉｃｈｅｌｅｔ边界条件下Ｄｅｎｅｕｂｏｕｒｇ模模型的球对称含时结构。     

甲醇羰基化合成甲酸甲酯研究

在高压反应釜中对甲醇羰基化合成甲酸甲酯进行了研究。结果表明 ,在一氧化碳体积分数为 99.9% ;甲醇质量分数为 99.5% ,压力为 3 .8MPa时 ,催化剂甲醇钠浓度以 0 .4 mol/L,温度 80℃为佳 ,此时采用浓度为2 mol/L的不同助剂 (吡啶、DMF、二甲基亚砜 )可使甲酸甲酯的时空收率达 2 84 g/(L· h)以上 ,比不加助剂时分别增至 1 .2 6～ 1 .1 3倍     

Adaptive spacetime discontinuous Galerkin method for hyperbolic advection–diffusion with a non‐negativity constraint

Applications where the diffusive and advective time scales are of similar order give rise to advection–diffusion phenomena that are inconsistent with the predictions of parabolic Fickian diffusion models. Non‐Fickian diffusion relations can capture these phenomena and remedy the paradox of infinite propagation speeds in Fickian models. In this work, we implement a modified, frame‐invariant form of Cattaneo's hyperbolic diffusion relation within a spacetime discontinuous Galerkin advection–diffusion model. An h‐adaptive spacetime meshing procedure supports an asynchronous, patch‐by‐patch solution procedure with linear computational complexity in the number of spacetime elements. This localized solver enables the selective application of optimization algorithms in only those patches that require inequality constraints to ensure a non‐negative concentration solution. In contrast to some previous methods, we do not modify the numerical fluxes to enforce non‐negative concentrations. Thus, the element‐wise conservation properties that are intrinsic to discontinuous Galerkin models are defined with respect to physically meaningful Riemann fluxes on the element boundaries. We present numerical examples that demonstrate the effectiveness of the proposed model, and we explore the distinct features of hyperbolic advection–diffusion response in subcritical and supercritical flows. Copyright © 2015 John Wiley & Sons, Ltd.     

一类新的射影平坦的Finsler度量

利用Hamel射影平坦方程获得了一类新的Finsler度量F=αФ(b2,s)在开子集URn上射影平坦的充要条件,此类度量包含了由Bryant构造的Sn上具有正常旗曲率K=1,且测地线为大圆周的Finsler度量.     

A Riemannian scalar measure for diffusion tensor images

We study a well-known scalar quantity in Riemannian geometry, the Ricci scalar, in the context of diffusion tensor imaging (DTI), which is an emerging non-invasive medical imaging modality. We derive a physical interpretation for the Ricci scalar and explore experimentally its significance in DTI. We also extend the definition of the Ricci scalar to the case of high angular resolution diffusion imaging (HARDI) using Finsler geometry. We mention that the Ricci scalar is not only suitable for tensor valued image analysis, but it can be computed for any mapping .