Collaborative Research ITR/AP: Enabling Microscopic Simulators to Perform System-Level Analysis

协作研究 ITR/AP：使微观模拟器能够执行系统级分析

• 批准号: 0205584
• 负责人: Linda Petzold
• 金额: --
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-15 至 2006-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0205584&HistoricalAwards=false
• 关键词: Collaborative; Research; ITR; AP; Enabling

Research:An interdisciplinary research team, at four universities, is collaborating on this medium-size Information Technology Research (ITR) project aimed at systematically bridging the gap between microscopic descriptions of complex material systems and systems-level analysis of direct engineering importance. A mathematics-assisted computational methodology will be developed that will enable microscopic-level simulators to perform systems-level analysis directly, without the need to pass through an intermediate level description of the material system through macroscopic (partial differential or integro-differential) evolution equations. Specifically, an ensemble-averaged "coarse" time-stepper-based computational superstructure will be "wrapped around" state-of-the-art microscopic dynamic simulators, such as molecular dynamics, kinetic Monte Carlo, Lattice-Boltzmann or hybrid codes. This methodology will enable microscopic simulators to perform advanced systems-level analysis: stability, bifurcation, "coarse" integration, sensitivity, and control tasks, of complex, nonlinear distributed processes. The planned algorithms will run on massively parallel machines.The computational framework will consist of the following basic elements: (i) choice of statistics of interest (e.g. distribution moments) for describing the coarse behavior; (ii) "lifting" of a macroscopic initial condition to an ensemble of consistent microscopic configurations; (iii) evolution over the same (short) time period of each initial microscopic configuration in the ensemble according to a microscopic simulator that embodies the best current description of the physical system; (iv) averaging ("restriction") over the ensemble of the evolved microscopic configurations to provide a macroscopic evolved system state; and (v) execution of the previous three steps over a finite set of macroscopic initial conditions. This new approach is robust in its implementation and portable in its range of scientific and engineering applications. It has general applicability to all systems for which a macroscopic description is conceptually possible, yet unavailable in closed form. It circumvents the difficulty in obtaining and closing such macroscopic models, while computationally extracting precisely the information that would be obtained by a macroscopic model, had the model been available in closed form. This provides the link between ITR and a spectrum of application areas.Impact:The impact of the research will be on establishing a powerful and general link between state-of-the-art microscopic-level simulations and fast systems level analysis capabilities. Although the research focuses on specific problems in heterogeneous hard materials and complex fluids, the computational framework is applicable to a broad range of complex systems, including biological systems, their processing and function. Since it has the potential to revolutionize engineering systems-level analysis, it could have educational impact as well as furthering advances in microelectronics, bioinformatics and nanotechnology.

研究：四所大学的跨学科研究团队正在合作开展这个中型信息技术研究（ITR）项目，旨在系统地弥合复杂材料系统的微观描述与具有直接工程重要性的系统级分析之间的差距。 将开发一种数学辅助计算方法，使微观级模拟器能够直接执行系统级分析，而无需通过宏观（偏微分或积分微分）演化方程对材料系统进行中间级描述。 具体来说，基于集成平均“粗略”时间步进器的计算上层结构将“包裹”最先进的微观动态模拟器，例如分子动力学、动力学蒙特卡罗、格子-玻尔兹曼或混合代码。 这种方法将使微观模拟器能够执行先进的系统级分析：复杂、非线性分布式过程的稳定性、分叉、“粗”集成、灵敏度和控制任务。 计划的算法将在大规模并行机器上运行。计算框架将包含以下基本元素：（i）选择感兴趣的统计数据（例如分布矩）来描述粗略行为； (ii) 将宏观初始条件“提升”为一致的微观配置的集合； (iii) 根据体现物理系统当前最佳描述的微观模拟器，系综中每个初始微观配置在相同（短）时间内的演化； (iv) 对演化的微观配置的整体进行平均（“限制”）以提供宏观的演化系统状态； (v) 在一组有限的宏观初始条件上执行前三个步骤。 这种新方法的实施非常稳健，并且在科学和工程应用范围内具有可移植性。 它对所有在概念上可能进行宏观描述但无法以封闭形式描述的系统具有普遍适用性。 它避免了获取和关闭此类宏观模型的困难，同时通过计算精确提取宏观模型将获得的信息（如果该模型以封闭形式提供）。 这提供了 ITR 和一系列应用领域之间的联系。影响：该研究的影响将在于在最先进的微观级模拟和快速系统级分析能力之间建立强大且普遍的联系。 尽管该研究重点关注异质硬材料和复杂流体中的具体问题，但计算框架适用于广泛的复杂系统，包括生物系统及其处理和功能。 由于它有可能彻底改变工程系统级分析，因此可能会产生教育影响，并进一步推动微电子、生物信息学和纳米技术的进步。