ITR/AP COLLABORATIVE RESEARCH: Real Time Optimization for Data Assimilation and Control of Large Scale Dynamic Simulations

该项目将创建并应用用于在线模拟的算法和软件工具，这些算法和软件工具不断地（1）从动态物理过程中吸收传感器数据，以及（2）为其控制生成最佳策略。 许多关键的工业、科学和社会问题都将从这项研究中受益，例如空气动力学、能源、地球物理学、基础设施、制造、医学、化学过程和环境应用；其中两项将是当前研究的重点。在这些和许多其他情况下，基础模型已经能够具有足够的保真度来产生有意义的预测，前提是可以使用观测数据适当地估计未知参数（通常是初始/边界条件、材料系数、源或几何形状）。关键步骤是解决受模拟方程（通常是偏微分方程或其降阶模型）约束的大规模非线性优化问题。数据同化阶段将通过调整 PDE 模拟的未知参数来寻求最小化传感器数据和基于模型的预测之间的不匹配，而最优控制阶段将根据更新的模型找到最优控制策略。尽管硬件、网络、并行 PDE 求解器、大规模优化算法和实时 ODE 优化取得了进步，但在实现实时 PDE 数据同化和最优控制的最终目标之前，必须克服重大的算法和软件挑战。需要的是全新的 PDE 优化算法，该算法必须：(1) 运行得足够快，以便能够在感兴趣的时间尺度上做出决策； (2) 扩展到表征偏微分方程优化的大量变量和约束以及表征高端系统的处理器； (3)适应不同解算精度要求； (4) 目标与时间相关的目标和约束； (5) 容忍不完整、不确定或错误的数据； (6) 能够引导当前的解决方案； (7) 提前终止时产生有意义的结果；为了创建、应用和传播实时偏微分方程数据同化和最优控制的支持技术，该项目将： (1) 开发满足上述一类重要应用规范的实时数据同化和最优控制算法和工具。 (2) 在面向对象的框架内实现和公开分发这些算法，该框架结合了问题结构，与高性能 PDE 求解器库轻松连接，促进了我们的工具对各种实时数据同化和最优控制问题的适用性，并能够在不干扰应用程序的情况下扩展算法。 (3) 将这些算法和工具应用于两个关键的环境和工业问题：化学气相沉积 (CVD) 反应器和荒地火势蔓延的建模和控制。 (4) 与其他用户社区互动和合作，以确保我们生产的算法和软件在广泛的应用程序中有用。

This project will create and apply algorithms and software tools for on-line simulations that continuously (1) assimilate sensor data from dynamic physical processes, and (2) generate optimal strategies for their control. A number of critical industrial, scientific, and societal problems stand to benefit from this research such as aerodynamics, energy, geophysics, infrastructure, manufacturing, medicine, chemical process and environmental applications; two of these will be the focus of the current research. In these and many other cases, the underlying models have become capable of sufficient fidelity to yield meaningful predictions, provided unknown parameters (typically initial/boundary conditions, material coefficients, sources, or geometry) can be estimated appropriately using observational data.The critical step is the solution of a large-scale nonlinear optimization problem that is constrained by the simulation equations, typically PDEs or their reduced order models. A data assimilation phase will seek to minimize the mismatch between sensor data and model-based predictions by adjusting unknown parameters of the PDE simulation, and the optimal control phase will find an optimal control strategy based on the updated model.Despite advances in hardware, networks, parallel PDE solvers, large-scale optimization algorithms, and real-time ODE optimization, significant algorithmic and software challenges must be overcome before the ultimate goal of real-time PDE data assimilation and optimal control can be realized. Needed are fundamentally new PDE optimization algorithms that must: (1) run sufficiently quickly to permit decision-making at time scales of interest; (2) scale to the large numbers of variables and constraints that characterize PDE optimization and processors that characterize high-end systems; (3) adjust to different solution accuracy requirements; (4) target time-dependent objectives and constraints; (5) tolerate incomplete, uncertain, or errant data; (6) be capable of bootstrapping current solutions; (7) yield meaningful results when terminated prematurely; and (8) be robust in the face of ill-posedness.To create, apply, and disseminate the enabling technologies for real-time PDE data assimilation and optimal control, the project will: (1) Develop algorithms and tools for real-time data assimilation and optimal control that meet the above specifications for a class of important applications. (2) Implement and publicly distribute these algorithms within an object-oriented framework that incorporates problem structure, interfaces easily with high performance PDE solver libraries fosters applicability of our tools to a broad range of real-time data assimilation and optimal control problems, and enables extension of the algorithms without interfering with applications. (3) Apply these algorithms and tools to two critical environmental and industrial problems: modeling and control of chemical vapor deposition (CVD) reactors and of wildland firespread. (4) Interact and work with other user communities to ensure that the algorithms and software we produce are useful across a broad range of applications.