As an exemplary batch process control strategy, iterative learning model predictive control (ILMPC) progressively refines tracking performance through repeated trials. However, owing to its nature as a learning-controlled system, ILMPC usually demands that the durations of all trials be identical to enable the use of 2-dimensional receding horizon optimization. The practice of using trial lengths that vary randomly can create a deficiency in the assimilation of prior information, and may even cause the control update to cease. In reference to this issue, this article details a novel predictive modification strategy within the ILMPC. The strategy standardizes the length of process data for each trial by employing predicted sequences to fill in gaps from missing running periods at each trial's concluding stage. The modification strategy guarantees the convergence of the conventional ILMPC, as evidenced by an inequality condition contingent upon the probability distribution of trial lengths. For prediction-based modifications in practical batch processes with intricate nonlinearities, a two-dimensional neural network predictive model, featuring parameter adaptation across trials, is created to generate highly accurate compensation data. To adapt learning strategy, an event-based switching mechanism is proposed within ILMPC. This method utilizes the probability of trial length change to guide the order of learning, ensuring recent trials are prioritized while historical data is effectively utilized. Under two distinct switching conditions, the theoretical convergence of the nonlinear, event-driven switching ILMPC system is examined. The proposed control methods' superiority is evident through simulations on a numerical example and the validation of the injection molding process.
Research into capacitive micromachined ultrasound transducers (CMUTs) has spanned more than twenty-five years, driven by their prospects for widespread manufacturing and seamless electronic integration. Prior to recent advancements, CMUTs were built by assembling numerous tiny membranes into a single transducer element. Subsequently, sub-optimal electromechanical efficiency and transmit performance were observed, thus the resulting devices were not always competitive with piezoelectric transducers. Previous CMUT devices, moreover, frequently suffered from dielectric charging and operational hysteresis, resulting in reduced long-term dependability. A recently demonstrated CMUT architecture utilizes a single, extended rectangular membrane per transducer element, incorporating innovative electrode post structures. This architecture's performance benefits extend beyond long-term reliability, outperforming previously published CMUT and piezoelectric arrays. We present in this paper the performance gains, along with the fabrication process's details, offering best practices to avoid the common pitfalls. Sufficient detail is presented to motivate the development of a new class of microfabricated transducers, with the expectation of enhancing performance in subsequent ultrasound systems.
This research proposes a strategy for enhancing workplace cognitive vigilance and minimizing the associated mental stress. An experiment was devised to induce stress in participants through the Stroop Color-Word Task (SCWT), under conditions of time pressure and negative reinforcement. For the purpose of enhancing cognitive vigilance and mitigating stress, we utilized 16 Hz binaural beats auditory stimulation (BBs) for a period of 10 minutes. Using Functional Near-Infrared Spectroscopy (fNIRS), salivary alpha-amylase, and behavioral responses, the stress level was quantified. Utilizing reaction time to stimuli (RT), accuracy of target detection, directed functional connectivity based on partial directed coherence, graph theory measures, and the laterality index (LI), the degree of stress was determined. Substantial increases in target detection accuracy (2183%, p < 0.0001) and reductions in salivary alpha amylase levels (3028%, p < 0.001) were observed when exposed to 16 Hz BBs, demonstrating their effectiveness in reducing mental stress. Analysis of partial directed coherence, graph theory metrics, and LI data indicated a decrease in information flow from the left to right prefrontal cortex during mental stress. In contrast, 16 Hz brainwaves (BBs) notably boosted vigilance and decreased stress by enhancing connectivity in the dorsolateral and left ventrolateral prefrontal cortex.
Stroke frequently leaves patients with motor and sensory impairments, which in turn lead to difficulties in walking. Selnoflast ic50 Analyzing muscle control mechanisms during walking can provide clues about neurological changes after a stroke; however, how stroke influences individual muscle actions and the synchronization of muscles across different phases of gait requires additional study. This investigation into ankle muscle activity and intermuscular coupling patterns in post-stroke patients will focus on the specific phases of movement they experience. integrated bio-behavioral surveillance Ten post-stroke patients, ten young healthy individuals, and ten elderly healthy subjects participated in this experiment. While walking at their preferred speeds on the ground, all subjects had their surface electromyography (sEMG) and marker trajectory data collected concurrently. The labeled trajectory data enabled a segmentation of each subject's gait cycle into four substages. Thermal Cyclers The intricacy of ankle muscle activity during walking was explored by implementing fuzzy approximate entropy (fApEn). An investigation into directed information transmission between ankle muscles employed transfer entropy (TE). Patients recovering from stroke demonstrated comparable patterns of ankle muscle activity complexity as healthy individuals, as the results show. The pattern of ankle muscle activity in stroke patients becomes more complex, deviating from that seen in healthy individuals, in the majority of gait sub-phases. The trend of ankle muscle TE values in stroke patients is a downward trajectory throughout the gait cycle, most pronounced during the second double support period. Patients, when contrasted with age-matched healthy controls, demonstrate a higher degree of motor unit recruitment during locomotion, coupled with enhanced muscle coordination, in order to execute gait. The concurrent use of fApEn and TE provides a more extensive understanding of how muscle modulation varies with phases of recovery in post-stroke patients.
The process of sleep staging is essential for assessing sleep quality and diagnosing sleep-related medical conditions. Time-domain data tends to be the primary focus in most existing automatic sleep staging methods, leading to the neglect of the intricate transformation relationship between sleep stages. We posit a novel Temporal-Spectral fused Attention-based deep neural network, TSA-Net, to facilitate automatic sleep staging, utilizing a single-channel EEG input. A two-stream feature extractor, feature context learning, and conditional random field (CRF) constitute the TSA-Net. The two-stream feature extractor's automatic extraction and fusion of EEG features from time and frequency domains leverages the abundant distinguishing information available in both temporal and spectral features for sleep staging. Next, the feature context learning module, by means of the multi-head self-attention mechanism, analyzes the dependencies between features, generating a preliminary sleep stage. The CRF module, in its final step, employs transition rules for a more precise classification. For the purpose of evaluating our model, we leverage two public datasets, namely Sleep-EDF-20 and Sleep-EDF-78. The Fpz-Cz channel's performance under the TSA-Net reveals accuracy scores of 8664% and 8221%, respectively. Empirical evidence suggests that TSA-Net optimizes sleep stage classification, demonstrating superior accuracy compared to the most advanced existing approaches.
The enhancement of life's comforts has resulted in a greater focus on the quality of sleep for people. An electroencephalogram (EEG)-based system for classifying sleep stages is beneficial in the evaluation of sleep quality and the detection of sleep disorders. Human-led design remains the standard for most automatic staging neural networks at this point, a methodology that is both time-consuming and demanding. A novel neural architecture search (NAS) framework, based on a bilevel optimization approximation, is proposed in this paper for the purpose of EEG-based sleep stage classification. The proposed NAS architecture primarily employs a bilevel optimization approximation for the purpose of architectural search. Model optimization is achieved by approximating the search space and regularizing it, with shared parameters across all the constituent cells. Finally, the model produced by NAS was tested on the Sleep-EDF-20, Sleep-EDF-78, and SHHS datasets, with an average accuracy of 827%, 800%, and 819%, respectively. The proposed NAS algorithm, evidenced by experimental results, serves as a useful guide for later automated network designs in the context of sleep stage classification.
The intricate connection between visual information presented through images and natural language descriptions remains a significant hurdle in the field of computer vision. To locate answers to posed questions, conventional deep supervision techniques rely on datasets that include a restricted number of images, along with textual descriptions as a ground truth. In the face of limited labeled data for learning, the prospect of building a vast dataset of several million visuals, meticulously annotated with texts, is enticing; unfortunately, this approach is exceedingly time-consuming and fraught with significant challenges. Knowledge graphs (KGs), in knowledge-based systems, are frequently treated as static lookup tables, failing to harness the dynamic updates within the graph. We propose a Webly supervised model, incorporating knowledge embedding, to facilitate visual reasoning. Benefiting from the overwhelming success of Webly supervised learning, we frequently employ web images, coupled with their weakly labeled text data, to develop an effective representation.