With advancements in sensor technology, high dimensional signals such as functional curves and images are typically collected from multiple sensors to characterize the degradation of a system. data fusion methods are ...
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With advancements in sensor technology, high dimensional signals such as functional curves and images are typically collected from multiple sensors to characterize the degradation of a system. data fusion methods are employed to integrate multisensor signals generated from the system into a scalar health index (HI) to understand the degradation status of the system. This paper develops sparse group LASSO-principal component analysis (SGL-PCA), a method that constructs HIs for image and profile data. First, we remove the smooth background from each sensor signal. Then, we solve the degradation patterns and the degradation paths through a rank-one matrix approximation problem, with the consideration of the sparsity of the measurements related to the degradation process and the monotonicity of the degradation paths. Results from a simulation study and a case study illustrate that the HI constructed by the proposed method outperforms the benchmark methods in identifying the measurements subject to the degradation process and predicting the remaining useful life of the system.
The soft robot is a kind of robot with high degree of freedom and continuous deformation. It is mostly made of soft materials, which has the characteristics of high flexibility and high task adaptability. Due to the s...
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Digital innovation is an important and evolving process that refers to the transformation and integration of digital technologies into various aspects of everyday life and work. In this context, innovative digital sol...
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ISBN:
(纸本)9798400704666
Digital innovation is an important and evolving process that refers to the transformation and integration of digital technologies into various aspects of everyday life and work. In this context, innovative digital solutions are often adopted and developed, including the Internet of Things (IoT). In order to fully understand the potential, trends, and challenges related to the implementation of these technologies in data management, we seek to identify the most promising architectural choices for an IoT infrastructure from the perspective of key aspects in the context of data Management. In this way, we aim to provide a comprehensive overview of IoT systems to guide organizations towards more informed decisions, offering cutting-edge solutions and contributing to digital transformation. This work aims to examine aspects such as data Collection, data Aggregation, data Integration, data Security, data Retention, and dataanalysis, with particular attention to emerging challenges in these contexts. Within the context of digital innovation, our study focuses on several areas of interest. For example, in the field of smart cities, we explore how the use of Cloud, Fog, and Edge Computing technologies can improve video surveillance and promote the use of Artificial Intelligence (AI) for better management of smart cities. Cloud computing, characterized by centralized dataprocessing and storage, represents a well established paradigm of IoT infrastructure. Fog computing extends these capabilities to the network edge, bringing computation and data storage closer to the data source, thereby reducing latency and enhancing real-time processing. Edge computing takes this concept further by processing data directly at or near the data source, minimizing the need for data to traverse long distances to centralized hubs, thus enabling even faster response times and improved efficiency. Additionally, we examine how human-centric methods and user modeling tools can facilitate the trans
data analysts have long sought to turn unstructured text data into meaningful concepts. Though common, topic modeling and clustering focus on lower-level keywords and require significant interpretative work. We introd...
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ISBN:
(纸本)9798400703300
data analysts have long sought to turn unstructured text data into meaningful concepts. Though common, topic modeling and clustering focus on lower-level keywords and require significant interpretative work. We introduce concept induction, a computational process that instead produces high-level concepts, defined by explicit inclusion criteria, from unstructured text. For a dataset of toxic online comments, where a state-of-the-art BERTopic model outputs "women, power, female," concept induction produces high-level concepts such as "Criticism of traditional gender roles" and "Dismissal of women's concerns." We present LLooM, a concept induction algorithm that leverages large language models to iteratively synthesize sampled text and propose human-interpretable concepts of increasing generality. We then instantiate LLooM in a mixed-initiative text analysis tool, enabling analysts to shift their attention from interpreting topics to engaging in theory-driven analysis. Through technical evaluations and four analysis scenarios ranging from literature review to content moderation, we find that LLooM's concepts improve upon the prior art of topic models in terms of quality and data coverage. In expert case studies, LLooM helped researchers to uncover new insights even from familiar datasets, for example by suggesting a previously unnoticed concept of attacks on out-party stances in a political social media dataset.
Recently, Contrastive Learning (CL) has made impressive progress in natural language processing, especially in sentence representation learning. Plenty of data augmentation methods have been proposed for the generatio...
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Recently, Contrastive Learning (CL) has made impressive progress in natural language processing, especially in sentence representation learning. Plenty of data augmentation methods have been proposed for the generation of positive samples. However, due to the highly abstract nature of natural language, these augmentations cannot maintain the quality of generated positive samples, e.g., too easy or hard samples. To this end, we propose to improve the quality of positive examples from a data arrangement perspective and develop a novel model-agnostic approach: Dynamic Curriculum Learning based Contrastive Sentence Embedding framework (DCLCSE) for sentence embeddings. Specifically, we propose to incorporate a curriculum learning strategy to control the positive example usage. At the early learning stage, easy samples are selected to optimize the CL-based model. As the model's capability increases, we gradually select harder samples for model training, ensuring the learning efficiency of the model. Furthermore, we design a novel difficulty measurement module to calculate the difficulty of generated positives, in which the model's capability is considered for the accurate sample difficulty measurement. Based on this, we develop multiple arrangement strategies to facilitate the model learning process based on learned difficulties. Finally, extensive experiments over multiple representative models demonstrate the superiority of DCLCSE. As a byproduct, we have released the codes to facilitate other researchers.
Intelligent control methods have led to a significant simplification of the robotic arm modeling and control tuning process, and thus they have been widely used. To further improve the precision of robotic arm motion ...
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ISBN:
(纸本)9798350377712;9798350377705
Intelligent control methods have led to a significant simplification of the robotic arm modeling and control tuning process, and thus they have been widely used. To further improve the precision of robotic arm motion control, this paper proposes a robotic arm motion control strategy based on a cascaded feature-enhanced elastic-net broad learning system (CFE-EN-BLS). This will fully extract data features to improve motion control accuracy. Moreover, ElasticNet regression is introduced to reduce feature redundancy. Finally, Lyapunov stability theory is introduced to constrain the learning parameters of the proposed learning method to enhance the convergence of the control strategy. The simulation and experiment show that the proposed control strategy can realize high-precision trajectory tracking control of the robotic arm.
choosing the right node to measure is the key to success in large-scale networks;network modeling is a critical tool for detecting performance. The growing size and complexity of modern networks make accurately predic...
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Laser metal deposition technology has found broad applications in the aerospace and marine industries due to its various advantages in terms of high material utilization and unlimited forming dimension. However, due t...
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In modern industrial cyber-physical systems, a mass of process variables has been obtained by the high-sampling online sensors. Meanwhile, the key quality indexes are usually obtained infrequently from the laboratory....
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Cascaded H-bridge (CHB) converters are suitable candidates for numerous applications, including electrical drives, static synchronous compensators, and battery energy storage inverters. Optimal control strategies for ...
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Cascaded H-bridge (CHB) converters are suitable candidates for numerous applications, including electrical drives, static synchronous compensators, and battery energy storage inverters. Optimal control strategies for CHB converters have attracted significant interest in recent decades due to their flexibility in including multiple control objectives and their simple design process. However, the steady-state performance of these control strategies deteriorates if the CHB converter model has parameter mismatches and/or the submodule (SM) capacitor voltage ripples are not measured. This work proposes a Kalman filter (KF) based strategy to eliminate the steady-state error and undesired low-frequency harmonic components in the CHB converter output currents. The proposed KF strategy estimates the instantaneous arm voltage harmonics representing the converter modeling errors and unaccounted disturbances. Then, these estimated voltage harmonics are used to improve the arm current predictions and obtain a compensation term for the steady-state arm voltage references to be used by the optimal control strategy. Experimental results for three different optimal control schemes are provided for a three-phase CHB converter with nine SMs to confirm the effectiveness of the proposed KF strategy.
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