Unmanned aerial vehicles (UAVs) have boosted modern living. Tiny, frail high-density targets, low resolution, complicated backgrounds, noise, and poor real-time exposure performance have augmented due to UAV firms. Re...
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Tristable energy harvesters(TEHs)have been proposed to achieve broad frequency bandwidth and superior low-frequency energy harvesting ***,due to the coexistence of three potential wells and the sensitivity to system c...
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Tristable energy harvesters(TEHs)have been proposed to achieve broad frequency bandwidth and superior low-frequency energy harvesting ***,due to the coexistence of three potential wells and the sensitivity to system conditions and external disturbances,the desired high-amplitude inter-well oscillation in the TEHs may be replaced by the chaotic or intra-well oscillations with inferior energy ***,the chaos has an unpredictable trajectory and may cause system damages,lessen the structural durability as well as require a more complicated circuit for power ***,in this paper,we firstly propose an adaptive finite-time disturbance observer(AFTDO)for performance enhancement of TEHs by detecting the external disturbances that induce the chaos,and reject them for the recovery of the desired inter-well *** proposed AFTDO eliminates the need to know in advance the upper bounds of imposed perturbations in conventional observers by means of the proposed adaptive protocols,leading to the higher efficacy of *** mathematical model of the piezoelectric TEH system and the AFTDO is *** demonstrate the effectiveness of the AFTDO,a series of numerical simulations have been *** show that for both cases with sinusoidal and impulsive disturbances,the AFTDO can successfully track the trajectories of the disturbance signals with the adaptive gain,and reject the disturbance to enable the TEH to sustain the periodic inter-well oscillation with effective energy harvesting performance.
Sentiment analysis is a technique of analyzing text to classify its emotion into positive, negative, or neutral sentiments. The main purpose of this study is to use sentiment analysis to seek Indonesian opinions about...
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Sentiment analysis is a technique of analyzing text to classify its emotion into positive, negative, or neutral sentiments. The main purpose of this study is to use sentiment analysis to seek Indonesian opinions about the chief of the Indonesian National Police. The dataset obtained from Twitter contains opinions toward the police chief from 20th August until 30th August 2022. Sentiment analysis can be done by using machine learning. Unfortunately, each machine learning algorithm performs differently depending on the data. This performance led to the issue of confusion in picking the best machine learning model to perform sentiment analysis, especially for unseen data. Therefore, ensemble learning is needed to combine multiple machine learning models. Bagging-based and Boosting-based ensemble learning have different algorithms. In order to get a high-performance model, Bagging-based and Boosting-based ensemble models can be combined as one model. This work proposed a second-level ensemble model called a multi-level ensemble model for sentiment analysis. It combines Multinomial Naive Bayes, Boosting-based ensemble learning, and Bagging-based ensemble learning. The data is processed using CountVectorizer to convert text into numbers and oversampling to handle imbalanced data. The experimental results show that our proposed model has the best results in terms of accuracy, precision, and F1-score for testing set compared to individual models.
Emotions play an essential role in the learning process and have an impact on how the learning process is eventually carried out. Facial expressions can be used to visually identify a person’s emotions. Along with th...
Emotions play an essential role in the learning process and have an impact on how the learning process is eventually carried out. Facial expressions can be used to visually identify a person’s emotions. Along with the advancement of computer vision and deep learning techniques, the study of human-computer interaction is increasingly focusing on the recognition of facial expressions. One of the main issues is the availability of sufficient datasets, especially for students. This study examined the deep learning architecture for face emotion classification. In addition, this research also introduces a new emotional dataset acquired from the junior high school student at SMP Negeri 1 Darul Imarah, Aceh Besar Regency, Indonesia. This dataset contains five classes that include the emotions of happiness, sadness, anger, surprise, and boredom. The dataset was then tested using the Mobile-Net architecture, the highest accuracy was achieved with a learning rate of 0.0001% of 88.492%. The dataset can be explored via the link https://***/USK-FEMO-DATASET/
This paper presents human pose estimation using millimeter-wave (mmWave) radar technology capable of penetrating obstacles. Operating within the frequency modulated continuous wave (FMCW) at 60 - 64 GHz, our radar sys...
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ISBN:
(数字)9798350383591
ISBN:
(纸本)9798350383607
This paper presents human pose estimation using millimeter-wave (mmWave) radar technology capable of penetrating obstacles. Operating within the frequency modulated continuous wave (FMCW) at 60 - 64 GHz, our radar system generates signals conducive to accurate human pose representation. Our data processing framework focuses on producing point cloud data, effectively capturing each human movement. Results are visualized through a 2D graph, with the z-axis representing time. Experimental data, collected from various activities conducted behind different walls, underwent thorough analysis, comparing point cloud positions with actual human postures. The outcomes affirm the effectiveness of mmWave radar systems, positioned behind obstacles, in accurately extracting human postures.
The electricity market's dynamics are significantly impacted by fluctuating prices, with participants trading based on these values. Accurate electricity price forecasting (EPF) enables energy suppliers to refine ...
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In this paper, the inverse linear quadratic(LQ) problem over finite time-horizon is *** the output observations of a dynamic process, the goal is to recover the corresponding LQ cost function. Firstly, by considering ...
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In this paper, the inverse linear quadratic(LQ) problem over finite time-horizon is *** the output observations of a dynamic process, the goal is to recover the corresponding LQ cost function. Firstly, by considering the inverse problem as an identification problem, its model structure is shown to be strictly globally identifiable under the assumption of system invertibility. Next, in the noiseless case a necessary and sufficient condition is proposed for the solvability of a positive semidefinite weighting matrix and its unique solution is obtained with two proposed algorithms under the condition of persistent excitation. Furthermore, a residual optimization problem is also formulated to solve a best-fit approximate cost function from sub-optimal observations. Finally, numerical simulations are used to demonstrate the effectiveness of the proposed methods.
This paper introduces a novel control framework to address the satisfaction of multiple time-varying output constraints in uncertain high-order MIMO nonlinear control systems. Unlike existing methods, which often assu...
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The paper develops a data-driven fuzzy modeling procedure based on level set to forecast cryptocurrencies prices. Data-driven level set is a novel fuzzy modeling method that differs from linguistic and functional fuzz...
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A critical task in environmental monitoring is the reconstruction of the density function of an event over the mission region. In such tasks, Unmanned Aerial Vehicles (UAVs) are employed as spatially distributed mobil...
A critical task in environmental monitoring is the reconstruction of the density function of an event over the mission region. In such tasks, Unmanned Aerial Vehicles (UAVs) are employed as spatially distributed mobile sensing agents. In this paper, we consider the cooperative coverage problem for a group of UAVs in the mission region with a time-varying density function. The density function is modeled by a Gaussian Mixture Model (GMM) with unknown parameters. By resorting to a consensus-based Expectation-Maximization (EM) approach, the GMM parameters are estimated based on the local observations of UAVs. Finally, the proposed strategy is applied to an offshore oil spill monitoring mission. The simulation results verify the theoretical results and demonstrate the competence of the proposed strategy for such applications.
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