Improved Long Short-Term Memory-based Wastewater Treatment Simulators for Deep Reinforcement Learning

Even though Deep Reinforcement Learning (DRL) showed outstanding results in the fields of Robotics and Games, it is still challenging to implement it in the optimization of industrial processes like wastewater treatment. One of the challenges is the lack of a simulation environment that will represent the actual plant as accurately as possible to train DRL policies. Stochasticity and non-linearity of wastewater treatment data lead to unstable and incorrect predictions of models over long time horizons. One possible reason for the models' incorrect simulation behavior can be related to the issue of compounding error, which is the accumulation of errors throughout the simulation. The compounding error occurs because the model utilizes its predictions as inputs at each time step. The error between the actual data and the prediction accumulates as the simulation continues. We implemented two methods to improve the trained models for wastewater treatment data, which resulted in more accurate simulators: 1- Using the model's prediction data as input in the training step as a tool of correction, and 2- Change in the loss function to consider the long-term predicted shape (dynamics). The experimental results showed that implementing these methods can improve the behavior of simulators in terms of Dynamic Time Warping throughout a year up to 98% compared to the base model. These improvements demonstrate significant promise in creating simulators for biological processes that do not need pre-existing knowledge of the process but instead depend exclusively on time series data obtained from the system.

Advancements in Point Cloud-Based 3D Defect Detection and Classification for Industrial Systems: A Comprehensive Survey

In recent years, 3D point clouds (PCs) have gained significant attention due to their diverse applications across various fields such as computer vision (CV), condition monitoring, virtual reality, robotics, autonomous driving etc. Deep learning (DL) has proven effective in leveraging 3D PCs to address various challenges previously encountered in 2D vision. However, the application of deep neural networks (DNN) to process 3D PCs presents its own set of challenges. To address these challenges, numerous methods have been proposed. This paper provides an in-depth review of recent advancements in DL-based condition monitoring (CM) using 3D PCs, with a specific focus on defect shape classification and segmentation within industrial applications for operational and maintenance purposes. Recognizing the crucial role of these aspects in industrial maintenance, the paper provides insightful observations that offer perspectives on the strengths and limitations of the reviewed DL-based PC processing methods. This synthesis of knowledge aims to contribute to the understanding and enhancement of CM processes, particularly within the framework of remaining useful life (RUL), in industrial systems.

Deep Learning Based Simulators for the Phosphorus Removal Process Control in Wastewater Treatment via Deep Reinforcement Learning Algorithms

Phosphorus removal is vital in wastewater treatment to reduce reliance on limited resources. Deep reinforcement learning (DRL) is a machine learning technique that can optimize complex and nonlinear systems, including the processes in wastewater treatment plants, by learning control policies through trial and error. However, applying DRL to chemical and biological processes is challenging due to the need for accurate simulators. This study trained six models to identify the phosphorus removal process and used them to create a simulator for the DRL environment. Although the models achieved high accuracy (>97%), uncertainty and incorrect prediction behavior limited their performance as simulators over longer horizons. Compounding errors in the models' predictions were identified as one of the causes of this problem. This approach for improving process control involves creating simulation environments for DRL algorithms, using data from supervisory control and data acquisition (SCADA) systems with a sufficient historical horizon without complex system modeling or parameter estimation.

A Fuzzy Time Series-Based Model Using Particle Swarm Optimization and Weighted Rules

During the last decades, a myriad of fuzzy time series models have been proposed in scientific literature. Among the most accurate models found in fuzzy time series, the high-order ones are the most accurate. The research described in this paper tackles three potential limitations associated with the application of high-order fuzzy time series models. To begin with, the adequacy of forecast rules lacks consistency. Secondly, as the model's order increases, data utilization diminishes. Thirdly, the uniformity of forecast rules proves to be highly contingent on the chosen interval partitions. To address these likely drawbacks, we introduce a novel model based on fuzzy time series that amalgamates the principles of particle swarm optimization (PSO) and weighted summation. Our results show that our approach models accurately the time series in comparison with previous methods.

Design, Modelling and Control of an Amphibious Quad-Rotor for Pipeline Inspection

Regular inspections are crucial to maintaining waste-water pipelines in good condition. The challenge is that inside a pipeline the space is narrow and may have a complex structure. The conventional methods that use pipe robots with heavy cables are expensive, time-consuming, and difficult to operate. In this work, we develop an amphibious system that combines a quad-copter with a surface vehicle, creating a hybrid unmanned aerial floating vehicle (HUAFV). Nonlinear dynamics of the HUAFV are modeled based on the dynamic models of both operating modes. The model is validated through experiments and simulations. A PI controller designed and tuned on the developed model is implemented onto a prototype platform. Our experiments demonstrate the effectiveness of the new HUAFV's modeling and design.