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Modeling and Simulation of a Single Catalytic Fixed Bed in an Ammonia Reactor

IFAC-PapersOnLine 2023年第2期56卷 6906-6912页

作者： Emil Skov Martinsen Joachim Weel Rosbo Anders H.D. Andersen Tobias K.S. Ritschel Steen Hørsholt Jakob Kjøbsted Huusom John Bagterp Jørgensen Department of Applied Mathematics and Computer Science Technical University of Denmark DK-2800 Kgs. Lyngby Denmark Department of Chemical Engineering Technical University of Denmark DK-2800 Kgs. Lyngby Denmark 2-control ApS DK-7400 Herning Denmark

We present a dynamical model of a single catalytic fixed bed in a quench-type ammonia reactor. This model consists of thermodynamics, kinetics, pressure loss, and mass and energy balances, which upon spatial discretisation results in a set of differential-algebraic equations. Compared to similar models in the literature, the main novelties in the model are: 1) a rigorous thermodynamic model using a thermodynamic software library; and 2) a correlation between the gas velocity and the pressure gradient throughout the bed, i.e. the pressure loss is included in the model and used to compute the gas velocity. We investigate steady state solutions and dynamical simulations to understand the behaviour of the single catalytic fixed bed. We determine the optimal steady state operational area and inverse response dynamics are observed. The model can be used to develop model-based control, which is relevant for dynamic and flexible operation of ammonia reactors in a Power-to-Ammonia plant.

关键词： Mathematical modeling Dynamical simulation Ammonia reactor Power-to-X

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Fractional Wavelet Combined with Multi-Scale Morphology and Pcnn Hybrid Algorithm for Grayscale Image Fusion

SSRN

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SSRN 2023年

作者： Xie, Minghang Zhang, Chenyang Liu, Ziyun Yang, Xiaozhong Institute of Information and Computation School of Mathematics and Physics North China Electric Power University Beijing102206 China School of Control and Computer Engineering North China Electric Power University Beijing102206 China

In the field of digital image processing, the role of grayscale image fusion cannot be ignored as it is essential for integrating image information. To address the issue of unclear edges caused by traditional image fusion algorithms, a hybrid algorithm combining the discrete fractional wavelet transform (DFRWT) with multi-scale morphology and the pulse coupled neural network (PCNN) is proposed. The hybrid algorithm utilizes two-dimensional DFRWT to decompose the source images to obtain the subbands including both high and low frequency components. Secondly, an image enhancement method improved by multi-scale morphological is constructed to process the low-frequency subband. In order to adapt the high-frequency component, we use a simplified PCNN method to derive the high-frequency decision map. The result of simulation experiments shows that this paper’s algorithm effectively suppresses the edge halo effect and Gibbs effect. The performance of the hybrid algorithm compared with the existing five classical algorithms is better. © 2023, The Authors. All rights reserved.

关键词： Image fusion

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Design and Realization of Unmanned Vehicle Autonomous Navigation System Based on Binocular Camera

Design and Realization of Unmanned Vehicle Autonomous Naviga...

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computer Science, Electronic Information engineering and Intelligent control Technology (CEI), IEEE International Conference on

作者： Tianxing Guo Lianlei Lin Huanyu Liu Junbao Li Department of Automatic Test and Control School of Electronics and Information Engineering Harbin Institute of Technology Harbin China Information Countermeasure Technique Institute School of Computer Science and Technology Harbin Institute of Technology Harbin China

ISBN: (数字)9798350372052

ISBN: (纸本)9798350372069

Aiming at the navigation problem of unmanned vehicles in extreme environments such as communication interference and limited GPS signals, this study proposes an autonomous navigation method based on binocular cameras. The method enables the unmanned vehicle to complete the task of localization and map building using only binocular images, without the need for other sensors or signal sources. Meanwhile, this study also proposes a local path planning obstacle avoidance method based on depth map, which, when combined with global localization information, can take into account both local obstacle avoidance and global path navigation, and can cope with random environmental changes. The system uses a single sensor for autonomous obstacle avoidance and navigation, which reduces the computational requirements and ensures the low cost of the navigation system. In order to verify the reliability and effectiveness of the system under signal-constrained conditions, the system is evaluated in a simulation environment and a real field scenario, respectively. The experimental results show that the system is able to achieve reliable localization and path planning under signal-constrained conditions.

关键词： Location awareness Navigation Reliability theory Path planning Sensor systems Sensors Collision avoidance

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Research on sales forecast based on prophet-SARIMA combination model 3

Research on sales forecast based on prophet-SARIMA combinati...

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2020 3rd International Symposium on Big Data and Applied Statistics, ISBDAS 2020

作者： Zhao, Jiantao Zhang, Chunwei School of Control and Computer Engineering North China Electric Power University Beijing102206 China

The stable development of e-commerce enterprises cannot be separated from scientific replenishment planning, and forecasting the sales volume of products helps e-commerce to make a reasonable replenishment plan, so as to speed up cash flow and reduce inventory pressure. Based on the in-depth study of Prophet model and seasonal differential autoregressive moving average model, as well as the analysis of daily sales volume of an e-commerce product from January 2015 to March 2018, a Prophet-SARIMA combination model for sales volume prediction is proposed. The principle of the combination model is to use prophet and SARIMA model to forecast the sales data respectively, and then weighted combination to get the final forecast results. Analyze and compare the prediction effect of single model and combination model. The first mock exam shows that the Prophet-SARIMA combination model has higher accuracy and stability in sales volume forecasting than single model. The sales volume forecast results of Prophet SARIMA combination model can provide an important basis for the e-commerce to supplement orders scientifically. © Published under licence by IOP Publishing Ltd.

关键词： Sales

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Research on coal mine safety monitoring data storage based on HBase 3

Research on coal mine safety monitoring data storage based o...

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2020 3rd International Conference on computer Information Science and Artificial Intelligence, CISAI 2020

作者： Jiang, Lizheng Li, Yanbin School of Control and Computer Engineering North China Electric Power University Beijing102206 China

In order to solve the problem of low storage efficiency and slow query speed when massive coal mine safety monitoring data is stored in relational database, a method of storage and retrieval based on HBase was designed. By combining the hash value of the combination of coal mine code, substation code and transducer code as well as the timestamp after inversion, the hot spot and data skew caused by the unreasonable design of rowkey in HBase were avoided. In order to improve the efficiency of data storage, the swing door trending (SDT) algorithm was used to compress the monitoring data, and in order to improve the efficiency of data retrieval, a secondary index based on ElasticSearch was constructed. The experimental results on the real coal mine data show that the efficiency of data storage and retrieval has been significantly improved. © Published under licence by IOP Publishing Ltd.

关键词： Coal mines

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Brief Survey of Model-Based Reinforcement Learning Techniques 24

Brief Survey of Model-Based Reinforcement Learning Technique...

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24th International Conference on System Theory, control and Computing, ICSTCC 2020

作者： Pal, Constantin-Valentin Leon, Florin Gheorghe Asachi Technical University of Iai Faculty of Automatic Control and Computer Engineering Iai Romania

ISBN: (数字)9781728198095

ISBN: (纸本)9781728198095

Model-free reinforcement learning (MFRL) usually has better asymptotic performance than the model-based reinforcement (MBRL) learning algorithms, especially in complex environments. But MBRL algorithms are very often much more sample-efficient, and sometimes are able to learn control tasks in just a handful of trials. In addition, in some domains, the MBRL algorithms can reach the MFRL performance with better sample efficiency. In recent years, MBRL research has increased in various application domains, such as robot control tasks, or game environments with complex observations. In this paper, we review the most popular techniques used in MBRL and look at some useful classification of algorithms in this area. © 2020 IEEE.

关键词： Reinforcement learning

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Network-based analysis to uncover drug-induced adverse side-effects

Network-based analysis to uncover drug-induced adverse side-...

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IEEE International Conference on Bioinformatics and Biomedicine (BIBM)

作者： Alessio Funari Paola Paci Federica Conte Department of Translational and Precision Medicine Sapienza University of Rome Rome Italy Institute for Systems Analysis and Computer Science "Antonio Ruberti" National Research Council Rome Italy Department of Computer Control and Management Engineering Sapienza University of Rome Rome Italy Karolinska Institutet Stockholm Sweden

Despite the drug approval process consists of extremely rigorous clinical and preclinical studies, not all side effects are identified before its marketing, posing a significant risk to public health. Furthermore, considering the huge use of economic and human resources, in-silico predictive approaches for the identification of side effects are essential. In this study, we introduce a new method based on random walk with restart algorithm to delineate previously unidentified links between drugs and side effects, and we apply it on the drug-induced Asthma and long QT syndrome. We identified the genes potentially involved in the development of the analyzed side effect by comparing side-effect-related drugs with drugs not known to induce side effects. Analyzing the sets of genes most likely influenced by the perturbation of each individual drug, we observed that, on average, side-effect-related drugs perturb a higher percentage of genes involved in the development of side effects compared to side-effect-unrelated drugs. Based on this finding, we developed a classifier to explore all possible unknown associations between drugs and side effects. This method can be extended to the analysis of other side effects as well.

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Soft Masked Transformer for Point Cloud Processing with Skip Attention-Based Upsampling

arXiv

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arXiv 2024年

作者： He, Yong Yu, Hongshan Ibrahim, Muhammad Liu, Xiaoyan Chen, Tongjia Ulhaq, Anwaar Mian, Ajmal The National Engineering Laboratory for Robot Visual Perception and Control Technology College of Electrical and Information Engineering Hunan University Lushan South Rd. Yuelu Dist. Changsha410082 China The Department of Computer Science The University of Western Australia WA6009 Australia Central Queensland University Sydney Campus Australia

Point cloud processing methods leverage local and global point features to cater to downstream tasks, yet they often overlook the task-level context inherent in point clouds during the encoding stage. We argue that integrating task-level information into the encoding stage significantly enhances performance. To that end, we propose SMTransformer which incorporates task-level information into a vector-based transformer by utilizing a soft mask generated from task-level queries and keys to learn the attention weights. Additionally, to facilitate effective communication between features from the encoding and decoding layers in high-level tasks such as segmentation, we introduce a skip-attention-based up-sampling block. This block dynamically fuses features from various resolution points across the encoding and decoding layers. To mitigate the increase in network parameters and training time resulting from the complexity of the aforementioned blocks, we propose a novel shared position encoding strategy. This strategy allows various transformer blocks to share the same position information over the same resolution points, thereby reducing network parameters and training time without compromising accuracy. Experimental comparisons with existing methods on multiple datasets demonstrate the efficacy of SMTransformer and skip-attention-based up-sampling for point cloud processing tasks, including semantic segmentation and classification. In particular, we achieve state-of-the-art semantic segmentation results of 73.4% mIoU on S3DIS Area 5 and 62.4% mIoU on SWAN dataset. Copyright © 2024, The Authors. All rights reserved.

关键词： Decoding

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Seamless Graph Task Scheduling over Dynamic Vehicular Clouds: A Hybrid Methodology for Integrating Pilot and Instantaneous Decisions

arXiv

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arXiv 2025年

作者： Guo, Bingshuo Liwang, Minghui Xia, Xiaoyu Li, Li Jiao, Zhenzhen Hosseinalipour, Seyyedali Wang, Xianbin School of Informatics Xiamen University Fujian China School of Computing Technologies RMIT University MelbourneVIC Australia Department of Control Science and Engineering Tongji University Shanghai China iF-Labs Beijing Teleinfo Technology Co. Ltd. CAICT China Department of Electrical Engineering University at Buffalo-SUNY NY United States Department of Electrical and Computer Engineering Western University ON Canada

Vehicular clouds (VCs) play a crucial role in the Internet-of-Vehicles (IoV) ecosystem by securing essential computing resources for a wide range of tasks. This paPertackles the intricacies of resource provisioning in dynamic VCs for computation-intensive tasks, represented by undirected graphs for parallel processing over multiple vehicles. We model the dynamics of VCs by considering multiple factors, including varying communication quality among vehicles, fluctuating computing capabilities of vehicles, uncertain contact duration among vehicles, and dynamic data exchange costs between vehicles. Our primary goal is to obtain feasible assignments between task components and nearby vehicles, called templates, in a timely manner with minimized task completion time and data exchange overhead. To achieve this, we propose a hybrid graph task scheduling (P-HTS) methodology that combines offline and online decision-making modes. For the offline mode, we introduce an approach called risk-aware pilot isomorphic subgraph searching (RA-PilotISS), which predicts feasible solutions for task scheduling in advance based on historical information. Then, for the online mode, we propose time-efficient instantaneous isomorphic subgraph searching (TE-InstaISS), serving as a backup approach for quickly identifying new optimal scheduling template when the one identified by RA-PilotISS becomes invalid due to changing conditions. Through comprehensive experiments, we demonstrate the superiority of our proposed hybrid mechanism compared to state-of-the-art methods in terms of various evaluative metrics, e.g., time efficiency such as the delay caused by seeking for possible templates and task completion time, as well as cost function, upon considering different VC scales and graph task topologies. Copyright © 2025, The Authors. All rights reserved.

关键词： Cost functions

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Lunar Asset Messaging and on Orbit Navigation (LA MOON)

Lunar Asset Messaging and on Orbit Navigation (LA MOON)

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IAF Space Exploration Symposium 2021 at the 72nd International Astronautical Congress, IAC 2021

作者： Derewa, Chrishma Holt, Samuel Lally, Michael Trybula, Robert Yuan, Christine Coble, Kyle Huang, Calvin Jet Propulsion Laboratory California Institute of Technology United States University of Colorado Boulder Aerospace Engineering United States New York University Computer Science United States University of Southern California Computer Science United States Cornell University Mechanical Engineering United States Kth Royal Institute of Technology Systems Control and Robotics Pasadena City College Computer Science United States

ISBN: (纸本)9781713842965

NASA has titled its 2020 thrust for the Moon, Artemis. The increased focus on the Moon as a destination for future human and robotic expeditions necessitates general purpose navigational and communications infrastructure reducing their complexity to help establish a sustained presence. A framework through which Lunar missions can relay communications and localize their positions shifts the burden from the individual mission and enables resource allocation tailored to mission-specific goals. During the summer of 2020, student interns under the Innovation to Flight (i2F) program at the National Aeronautics and Space Administration s (NASA) Jet Propulsion Laboratory (JPL) in collaboration with the University of Colorado Boulder designed, built, and tested a prototype framework capable of providing surface assets with communication and positioning services. The team utilized the existing i2F CubeSat bus in addition to developing several CubeSat engineering development units (EDUs), a ground vehicle, and a ground station to simulate a scenario in which a lunar surface mission is supported by these services. A primary goal of the summer was to develop a method for localizing the ground vehicle through trilateration. Distances are inferred from the round-Trip time of flight (ToF) of radio signals between an asset and several elements. Signals were sent and received using LimeSDR software defined radios on-board both the ground vehicle and the EDUs;ToF and trilateration were calculated on a Qualcomm Snapdragon development board located within the LA MOON payload data system. The ModalAI chipset on the Qualcomm was instrumental in executing visual based position estimation. Communications was facilitated through a bent-pipe approach addressing the NASA requirement to provide solutions for in communication denied locations. The ground vehicle relayed information to other surface assets in addition to its ground station through the supporting constellation. This project demons

关键词： Orbits

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