In recent years, the field of data-driven neural network-based machine
learning (ML) algorithms has grown significantly and spurred research in its
applicability to instrumentation and control systems. While they are promising
in operational contexts, the trustworthiness of such algorithms is not
adequately assessed. Failures of ML-integrated systems are poorly understood;
the lack of comprehensive risk modeling can degrade the trustworthiness of
these systems. In recent reports by the National Institute for Standards and
Technology, trustworthiness in ML is a critical barrier to adoption and will
play a vital role in intelligent systems' safe and accountable operation. Thus,
in this work, we demonstrate a real-time model-agnostic method to evaluate the
relative reliability of ML predictions by incorporating out-of-distribution
detection on the training dataset. It is well documented that ML algorithms
excel at interpolation (or near-interpolation) tasks but significantly degrade
at extrapolation. This occurs when new samples are "far" from training samples.
The method, referred to as the Laplacian distributed decay for reliability
(LADDR), determines the difference between the operational and training
datasets, which is used to calculate a prediction's relative reliability. LADDR
is demonstrated on a feedforward neural network-based model used to predict
safety significant factors during different loss-of-flow transients. LADDR is
intended as a "data supervisor" and determines the appropriateness of
well-trained ML models in the context of operational conditions. Ultimately,
LADDR illustrates how training data can be used as evidence to support the
trustworthiness of ML predictions when utilized for conventional interpolation
tasks.

通过将数据监督引入机器学习预测模型，我们提出了一种实时模型无关的方法，评估机器学习预测的相对可靠性，并通过针对操作数据集与训练数据集之间的差异来计算预测的相对可靠性，用以支持机器学习预测在常规插值任务中的可信度。

仪器与控制系统中集成的机器学习方法的动态模型无关可信度评估

Dynamic Model Agnostic Reliability Evaluation of Machine-Learning  Methods Integrated in Instrumentation & Control Systems

Managing divertor plasmas is crucial for operating reactor scale tokamak
devices due to heat and particle flux constraints on the divertor target.
Simulation is an important tool to understand and control these plasmas,
however, for real-time applications or exhaustive parameter scans only simple
approximations are currently fast enough. We address this lack of fast
simulators using neural PDE surrogates, data-driven neural network-based
surrogate models trained using solutions generated with a classical numerical
method. The surrogate approximates a time-stepping operator that evolves the
full spatial solution of a reference physics-based model over time. We use
DIV1D, a 1D dynamic model of the divertor plasma, as reference model to
generate data. DIV1D's domain covers a 1D heat flux tube from the X-point
(upstream) to the target. We simulate a realistic TCV divertor plasma with
dynamics induced by upstream density ramps and provide an exploratory outlook
towards fast transients. State-of-the-art neural PDE surrogates are evaluated
in a common framework and extended for properties of the DIV1D data. We
evaluate (1) the speed-accuracy trade-off; (2) recreating non-linear behavior;
(3) data efficiency; and (4) parameter inter- and extrapolation. Once trained,
neural PDE surrogates can faithfully approximate DIV1D's divertor plasma
dynamics at sub real-time computation speeds: In the proposed configuration,
2ms of plasma dynamics can be computed in $\approx$0.63ms of wall-clock time,
several orders of magnitude faster than DIV1D.

本文介绍使用神经偏微分方程代理进行快速模拟离子流中等离子体物理过程的方法，并通过 DIV1D 模型数据进行了实验验证。