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Soft sensor for monitoring dynamic changes in cell composition

IFAC-PapersOnLine 2022年第23期55卷 98-103页

作者： Sebastián Espinel-Ríos Bruno Morabito Katja Bettenbrock Steffen Klamt Rolf Findeisen Laboratory for System Theory and Automatic Control Otto von Guericke University Magdeburg Germany Analysis and Redesign of Biological Networks Max Planck Institute for Dynamics of Complex Technical Systems Germany Bioprocess Engineering Max Planck Institute for Dynamics of Complex Technical Systems Germany Control and Cyber-Physical Systems Laboratory TU Darmstadt Germany

Precise and accurate online monitoring methods are needed to enable smart biomanufacturing and automation. Most of the sensors available focus on process parameters such as metabolite and dissolved gas concentrations, cell density or viability, among other variables like pH, temperature, etc. In this work, we develop a soft sensor algorithm to estimate the cell composition online, a very important aspect often overlooked in the bioprocess monitoring literature. Our strategy is based on full information estimation, an optimization-based estimator that takes into account the dynamics of the cell metabolism and considers all the available measurements from the beginning of the process, thus it has a memory effect. Being able to track dynamic changes in cell composition can open the door to promising applications, e.g., predictive control and automation of biosystems. As a case study, we consider the Escherichia co li’ s metabolism growing on glycerol under different levels of oxygen supply. We compare the performance of our soft sensor method against resource balance analysis, a previously proposed estimator based on steady-state assumptions. Overall, the presented full information estimator was able to track the dynamic changes in cell composition significantly more accurately. We also discuss how our estimation strategy can be transformed into a moving horizon estimation, where only the available measurements in a fixed and moving window are considered, thereby reducing possible computational burdens.

关键词： Cell composition soft sensor full information estimation resource balance analysis dynamic enzyme-cost flux balance analysis

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Unmanned Vehicle Route Planning Based on Improved Artificial Potential Field Method 2

Unmanned Vehicle Route Planning Based on Improved Artificial...

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2019 2nd International Conference on Computer Information Science and Artificial Intelligence, CISAI 2019

作者： Zha, Min Wang, Zhiwen Feng, Jing Cao, Xinliang Control Theory and Control Engineering Guangxi University of Science and Technology Liuzhou Guangxi545006 China Computer Science and Communication Engineering Guangxi University of Science and Technology Liuzhou Guangxi545006 China

Aiming at the defect of target unreachable and local minimum in the unmanned path planning by traditional artificial potential field method, an improved artificial potential field method is proposed in this paper. By rotating the repulsive force by a certain angle, the unmanned vehicle jumps out of the local minimum point, and adopts the safety distance and the adjustment factor in the repulsive field to solve the problem of the target unreachability, and also ensures the safety of unmanned vehicles during obstacle avoidance. The experimental results show that the improved artificial potential field method can better achieve the safe obstacle avoidance of driverless vehicles and effectively plan the optimal target path. © Published under licence by IOP Publishing Ltd.

关键词： Safety factor

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Cell-free biosynthesis meets dynamic optimization and control: a fed-batch framework

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IFAC-PapersOnLine 2022年第23期55卷 92-97页

作者： Sebastián Espinel-Ríos Nicolas Huber Edgar Alberto Alcalá-Orozco Bruno Morabito Thomas F.T. Rexer Udo Reichl Steffen Klamt Rolf Findeisen Laboratory for System Theory and Automatic Control Otto von Guericke University Magdeburg Germany Analysis and Redesign of Biological Networks Max Planck Institute for Dynamics of Complex Technical Systems Germany Bioprocess Engineering Max Planck Institute for Dynamics of Complex Technical Systems Germany Control and Cyber-Physical Systems Laboratory TU Darmstadt Germany

Cell-free biosynthesis uses the machinery of cells, such as the metabolic reactions, to carry out conversion processes in vitro. This can be more beneficial than in vivo approaches like fermentations. Some advantages of these synthetic biology processes include higher product yields, rates and titers, and more flexibility in pathway design. Cell-free biosynthesis is still in early stages and, unlike in vivo production, there are very few examples of model-based optimization. Moreover, we encounter static optimizations in most cases, neglecting the dynamic nature of the processes. We present an optimal control framework to maximize the efficiency of cell-free biosynthesis. We focus on fed-batch setups as they allow enhancing the reaction rates via the feeding, extending production processes for longer times, and minimizing the potential negative effects of enzyme kinetics with substrate inhibition. Our framework can in principle handle several cost functions and exploit both static and dynamic degrees of freedom. An aspect that can hinder model-based optimization is model uncertainty, which can arise due to uncertain parameters, oversimplified model assumptions or unknown reaction mechanisms. To counteract this, we propose the use of model predictive control during the process operation. In addition, we outline the use of moving horizon estimation as an observer in the case of unmeasured states. We consider the de novo cell-free synthesis of uridine diphosphate-N-acetylglucosamine as a biomedical relevant case study, where we were able to maximize the volumetric productivity in simulations, and indirectly also the titer and enzyme efficiency use.

关键词： Cell-free fed-batch optimization control state estimation UDP-GlcNAc

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Strategies for Enhancing Direct Interspecies Electron Transfer Induced by Granular Activated Carbon During Anaerobic Digestion of Fat, Oil, and Grease

SSRN

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SSRN 2025年

作者： He, Xia Chen, Jieying Xu, Weijia Lu, Yanqin College of Environmental Science and Engineering Guilin University of Technology Guangxi541006 China Modern Industry College of Ecology and Environmental Protection Guilin University of Technology Guilin541006 China Guangxi Key Laboratory of Theory and Technology for Environmental Pollution Control Guilin University of Technology Guilin541006 China

Adsorption of long chain fatty acids (LCFAs) on granular activated carbon (GAC) limits the establishment of direct interspecies electron transfer (DIET) via GAC during anaerobic digestion of fat, oil, and grease (FOG). Exploration of strategies for enhancing GAC-induced DIET for LCFAs degradation is vital for the application of GAC in FOG digestion. In this study, the influence of different strategies, combined with pre-mixing GAC with inoculum, inoculum acclimation, and inoculum size differentiation, on the enhancement of GAC-induced DIET was investigated. The results show that pre-mixing GAC with the large size acclimatized inoculum was the optimal strategy to reduce LCFAs adsorption on GAC and enhance GAC-induced DIET for LCFAs degradation, leading to 63.4% increment of methane production compared to the control. Using the optimal strategy, Exilispira, Geobacter, Methanosaeta, Methanolinea, and RBG-16-49-21 were highly enriched and cooperatively interacted on GAC, contributing to the enhanced acetate/propionate degradation and nitrogen conversion to accelerate LCFAs degradation. This simultaneously reduced the inhibitory effect of LCFAs in the digester, changed the microbial composition and the network of the suspended sludge, benefiting the methane production by suspended sludge. Overall, this work provides an in-depth understanding of the enhancement of GAC-induced DIET during FOG digestion. © 2025, The Authors. All rights reserved.

关键词： Anaerobic digestion

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Cooperative Global K-exponential Tracking control of Multiple Mobile Robots-Extended Version

arXiv

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arXiv 2024年

作者： Xu, Liang Su, Youfeng Cai, He College of Computer and Data Science Fuzhou University Fuzhou350116 China Shenzhen Key Laboratory of Control Theory and Intelligent Systems Southern University of Science and Technology Shenzhen518055 China School of Automation Science and Engineering South China University of Technology Guangzhou510641 China

This paper studies the cooperative tracking control problem for multiple mobile robots over a directed communication network. First, it is shown that the closed-loop system is uniformly globally asymptotically stable under the proposed distributed continuous feedback control law, where an explicit strict Lyapunov function is constructed. Then, by investigating the convergence rate, it is further proven that the closed-loop system is globally K-exponentially stable. Moreover, to make the proposed control law more practical, the distributed continuous feedback control law is generalized to a distributed sampled-data feedback control law using the emulation approach, based on the strong integral input-to-state stable Lyapunov function. Numerical simulations are presented to validate the effectiveness of the proposed control methods. Copyright © 2024, The Authors. All rights reserved.

关键词： Lyapunov functions

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Inverse Kalman Filtering for Systems with Correlated Noises

Inverse Kalman Filtering for Systems with Correlated Noises

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IEEE Conference on Decision and control

作者： Yibei Li Xiaoming Hu Bo Wahlberg Lihua Xie School of Electrical and Electronic Engineering Nanyang Technological University Singapore Department of Mathematics Division of Optimization and Systems Theory KTH Royal Institute of Technology Sweden Division of Decision and Control Systems School of Electrical Engineering and Computer Sciencem KTH Royal Institute of Technology Sweden

This paper focuses on two inverse problems of the Kalman filter in which the process and measurement noises are correlated. The unknown covariance matrix in a stochastic system is reconstructed from observations of its posterior beliefs. For the standard inverse Kalman filtering problem, a novel duality-based formulation is proposed, where a well-defined inverse optimal control (IOC) problem is solved instead. Identifiability of the underlying model is proved, and a least squares estimator is designed that is statistically consistent. The time-invariant case using the steady-state Kalman gain is further studied. Since this inverse problem is ill-posed, a canonical class of covariance matrices is constructed, which can be uniquely identified from the dataset with asymptotic convergence. Finally, the performances of the proposed methods are illustrated by numerical examples.

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On an exact solution to the nonlinear heat equation with a source

On an exact solution to the nonlinear heat equation with a s...

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2020 Dynamic Systems and Computer Science: theory and Applications, DYSC 2020

作者： Kazakov, A.L. Lempert, A.A. Spevak, L.F. Matrosov Institute for System Dynamics and Control Theory SB RAS 134 Lermontov Str. Irkutsk664033 Russia Institute of Engineering Science UB RAS 34 Komsomolskaya str. Ekaterinburg620049 Russia

The paper is devoted to the study of a singular nonlinear second-order parabolic equation, which is called the porous medium equation or the nonlinear heat equation. One of the important classes of its solutions is heat waves propagating over a zero background with a finite velocity. This property is not typical for parabolic equations and is a consequence of singularity. The main object of study is exact solutions of mentioned type. A new way of separating variables is used to represent them. We obtain conditions when it is possible to make a reduction to the Cauchy problem for an ordinary second-order differential equation with a singularity. It is shown that the Cauchy problemdescribes a heat wave whose front moves exponentially. We construct a solution to the Cauchy problem as a power series and determine the cases when the series breaks off, i.e. the solution has the form of a polynomial, and the corresponding heat wave can be written explicitly. If the Cauchy problem cannot be explicitly integrated, the solution is constructed numerically. An algorithm based on the boundary element method is proposed. We perform a computational experiment and conclude the properties of the found solutions. Besides, the accuracy of the calculation results is analyzed. © Published under licence by IOP Publishing Ltd.

关键词： Polynomials

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Fatigue Driving Detection of EEG Signals by LSTM Deep Neural Network with LPSD and DE

Fatigue Driving Detection of EEG Signals by LSTM Deep Neural...

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IEEE International Conference on Mechatronics and Automation

作者： Hao Zhang Enzeng Dong Jigang Tong Sen Yang Shengzhi Du Tianjin Key Laboratory for Control Theory & Applications in Complicated Systems and Intelligent Robot Laboratory Tianjin University of Technology 391 Binshui West Road Tianjin China Department of Electrical Engineering Tshwane University of Technology Pretoria South Africa

Fatigue driving detection has always been an urgent social problem to be solved, and many complex factors increase the difficulty of detection. Nowadays, more scholars choose to use multi-channel EEG signals for fatigue detection, which is accompanied by the development of deep learning networks. Here, we propose the deep Long Short Term Memory (LSTM) neural network with the Differential Entropy (DE) and Logarithm Power Spectrum Density (LPSD). We first divide the EEG signal into 8-s Hanning windows with 50% overlap, and then use the Short Time Fourier Transform(STFT) on the extracted time window to obtain 50 frequency sub-bands. Finally, LPSD and DE features are extracted from the frequency offspring obtained from the STFT and input into the deep LSTM neural network. The network can choose to learn more task related information by adding soft attention and extract effective time information from EEG signals,thereby improving the model’s performance in detecting driving fatigue. In addition, we also collected EEG signals from 8 subjects in both awake and fatigued states,and used the PERCLOS index to judge the degree of fatigue. Using the collected dataset, we compared the effectiveness of the deep LSTM neural network with five other methods. The results indicate that the deep LSTM neural network has a better classification accuracy of 93.12%. It proves that the network has good performance in fatigue detection of EEG signals.

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Sources, Removal Efficiency, and Risk Assessment of Pahs in Wastewater Treatment Plants with Three Different Treatment Processes

SSRN

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SSRN 2024年

作者： Fu, Ming-Ming Liu, Zi-Xuan Wang, Mei Huang, Gui-Bin Luo, Jun Zhang, Qin Bai, Shao-Yuan Xu, Dan-Dan Liu, Hui-Li Mo, Sheng-Peng Zhou, Xiao-Bin Zhang, Ya-Nan College of Environmental Science and Engineering Guilin University of Technology Guilin541004 China The Guangxi Key Laboratory of Theory and Technology for Environmental Pollution Control Guilin University of Technology Guilin541004 China Heng sheng Water Environment Treatment Co. Ltd. Guilin541100 China Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area Guilin University of Technology Guilin541004 China

Polycyclic aromatic hydrocarbons (PAHs) are prevalent in wastewater treatment plants (WWTPs), but there is a lack of effective, targeted methods to remove them. This study was conducted to investigate the removal pattern of 16 PAHs by three typical wastewater treatment processes (CASS, oxidation ditch, and A/A/O). The influent concentrations at the three WWTPs were 5085.67 ng/L, 14554.09 ng/L, and 13054.12 ng/L, respectively. The removal rates of PAHs by the three wastewater treatment processes were 60.35% for oxidation ditch, 54.88% for A/A/O, and 23.16% for CASS. The removal of PAHs from WWTPs relies mainly on biodegradation, especially anaerobic biodegradation. The removal of PAHs by the anaerobic processes of oxidation ditch and A/A/O was 55.55% and 49.54%, respectively. The primary source of PAHs at WWTP A is a petroleum source, WWTP B is a combustion source, and WWTP C is a mixed combustion and petroleum source. The Ecological Health Risk Assessment shows that the influent and effluent from all three WWTPs have a high-risk rating. The human health risk assessment showed that volatilization from the three WWTPs had a high carcinogenic risk. The study can provide a reference value for the upgrading of WWTPs and the formulation of related policies. © 2024, The Authors. All rights reserved.

关键词： Effluents

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TEMPORAL-SPATIAL REPRESENTATION LEARNING TRANSFORMER FOR EEG-BASED EMOTION RECOGNITION

arXiv

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arXiv 2022年

作者： Wang, Zhe Wang, Yongxiong Hu, Chuanfei Yin, Zhong Song, Yu School of Optical-Electrical and Computer Engineering University of Shanghai for Science and Technology China Key Laboratory of Measurement and Control of CSE Ministry of Education Southeast University China Tianjin Key Laboratory for Control Theory and Applications in Complicated Systems Tianjin University of Technology China

Both the temporal dynamics and spatial correlations of Electroencephalogram (EEG), which contain discriminative emotion information, are essential for the emotion recognition. However, some redundant information within the EEG signals would degrade the performance. Specifically, the subjects reach prospective intense emotions for only a fraction of the stimulus duration. Besides, it is a challenge to extract discriminative features from the complex spatial correlations among a number of electrodes. To deal with the problems, we propose a transformer-based model to robustly capture temporal dynamics and spatial correlations of EEG. Especially, temporal feature extractors which share the weight among all the EEG channels are designed to adaptively extract dynamic context information from raw signals. Furthermore, multi-head self-attention mechanism within the transformers could adaptively localize the vital EEG fragments and emphasize the essential brain regions which contribute to the performance. To verify the effectiveness of the proposed method, we conduct the experiments on two public datasets, DEAP and MAHNOB-HCI. The results demonstrate that the proposed method achieves outstanding performance on arousal and valence classification. Copyright © 2022, The Authors. All rights reserved.

关键词： Emotion Recognition

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