Modeling of Plasma Etch Systems Using Ordinary Least Squares, Recurrent Neural Network, and Projection to Latent Structure Models

Approximation Theory plays a central part in modern statistical methods, in particular in Neural Network modeling. These models are able to approximate a large amount of metric data structures in their entire range of definition or at least piecewise. We survey most of the known results for networks of neurone-like units. The connections to classical statistical ideas such as ordinary least squares (LS) are emphasized.

Download Full-text

Multiscale Modeling and Recurrent Neural Network Based Optimization of a Plasma Etch Process

Processes ◽

10.3390/pr9010151 ◽

2021 ◽

Vol 9 (1) ◽

pp. 151

Author(s):

Tianqi Xiao ◽

Dong Ni

Keyword(s):

Neural Network ◽

Multiscale Modeling ◽

Recurrent Neural Network ◽

Gas Flow ◽

Probability Function ◽

Fluid Model ◽

Open Loop ◽

Training Data ◽

Plasma Etch ◽

Etching Depth

In this article, we focus on the development of a multiscale modeling and recurrent neural network (RNN) based optimization framework of a plasma etch process on a three-dimensional substrate with uniform thickness using the inductive coupled plasma (ICP). Specifically, the gas flow and chemical reactions of plasma are simulated by a macroscopic fluid model. In addition, the etch process on the substrate is simulated by a kinetic Monte Carlo (kMC) model. While long time horizon optimization cannot be completed due to the computational complexity of the simulation models, RNN models are applied to approximate the fluid model and kMC model. The training data of RNN models are generated by open-loop simulations of the fluid model and the kMC model. Additionally, the stochastic characteristic of the kMC model is presented by a probability function. The well-trained RNN models and the probability function are then implemented in computing an open-loop optimization problem, in which a moving optimization method is applied to overcome the error accumulation problem when using RNN models. The optimization goal is to achieve the desired average etching depth and average bottom roughness within the least amount of time. The simulation results show that our prediction model is accurate enough and the optimization objectives can be completed well.

Download Full-text

Neural Networks for Estimating Speculative Attacks Models

Entropy ◽

10.3390/e23010106 ◽

2021 ◽

Vol 23 (1) ◽

pp. 106

Author(s):

David Alaminos ◽

Fernando Aguilar-Vijande ◽

José Ramón Sánchez-Serrano

Keyword(s):

Neural Network ◽

Least Squares ◽

Currency Crises ◽

Estimation Method ◽

Ordinary Least Squares ◽

Speculative Attacks ◽

Speculative Attack ◽

Network Methods ◽

Time Required ◽

Attack Models

Currency crises have been analyzed and modeled over the last few decades. These currency crises develop mainly due to a balance of payments crisis, and in many cases, these crises lead to speculative attacks against the price of the currency. Despite the popularity of these models, they are currently shown as models with low estimation precision. In the present study, estimates are made with first- and second-generation speculative attack models using neural network methods. The results conclude that the Quantum-Inspired Neural Network and Deep Neural Decision Trees methodologies are shown to be the most accurate, with results around 90% accuracy. These results exceed the estimates made with Ordinary Least Squares, the usual estimation method for speculative attack models. In addition, the time required for the estimation is less for neural network methods than for Ordinary Least Squares. These results can be of great importance for public and financial institutions when anticipating speculative pressures on currencies that are in price crisis in the markets.

Download Full-text

Research on behavior recognition based on feature fusion of automatic coder and recurrent neural network

Journal of Intelligent & Fuzzy Systems ◽

10.3233/jifs-189290 ◽

2020 ◽

Vol 39 (6) ◽

pp. 8927-8935

Author(s):

Bing Zheng ◽

Dawei Yun ◽

Yan Liang

Keyword(s):

Neural Network ◽

Recurrent Neural Network ◽

Behavior Pattern ◽

Rapid Development ◽

Video Data ◽

Support Vector ◽

Behavior Recognition ◽

Learning Methods ◽

The Impact ◽

Internet Of Things Technology

Under the impact of COVID-19, research on behavior recognition are highly needed. In this paper, we combine the algorithm of self-adaptive coder and recurrent neural network to realize the research of behavior pattern recognition. At present, most of the research of human behavior recognition is focused on the video data, which is based on the video number. At the same time, due to the complexity of video image data, it is easy to violate personal privacy. With the rapid development of Internet of things technology, it has attracted the attention of a large number of experts and scholars. Researchers have tried to use many machine learning methods, such as random forest, support vector machine and other shallow learning methods, which perform well in the laboratory environment, but there is still a long way to go from practical application. In this paper, a recursive neural network algorithm based on long and short term memory (LSTM) is proposed to realize the recognition of behavior patterns, so as to improve the accuracy of human activity behavior recognition.

Download Full-text