146 research outputs found

    Solution to an Optimal Control Problem via Canonical Dual Method

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    The analytic solution to an optimal control problem is investigated using the canonical dual method. By means of the Pontryagin principle and a transformation of the cost functional, the optimal control of a nonconvex problem is obtained. It turns out that the optimal control can be expressed by the costate via canonical dual variables. Some examples are illustrated

    Improving the Performance of PCA-Based Chiller Sensor Fault Detection by Sensitivity Analysis for the Training Data Set

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    An improved approach of fault detection for chiller sensors is presented based on the sensitivity analysis for the original data set used to train the Principal Component Analysis (PCA) model. Sensor faults are inevitable due to the aging, environment, location and so on. Meanwhile, because of the wide range of operational conditions, the fault of a certain sensor is very difficult to be directly detected by its own historical data. PCA is a multivariate data-based statistical analysis method and it is very useful for the sensor fault detection in HVAC&R. The undetectable zone of a certain sensor by Q-statistic is derived from the definition of Q-statistic which is usually employed as a boundary to detect the sensor fault situation. Due to the similar style between Q-statistic and Hawkins’ TH2, the undetectable zone by Hawkins’ TH2 is also obtained. Undetectable zone is a predictive index to indicate the detectability of different sensors by different statistics. Since undetectable zone is the character of the original training data set, it can indicate the quality for the selected training data. One field data set is employed to validate the presented approach. Results show that the undetectable zone of a certain sensor by Q-statistic is quite different from that by Hawkins’ TH2. Therefore, the undetectable zone can be used to improving the performance of PCA-based chiller sensor fault detection by choosing different fault detection statistics with less undetectable zone for different sensor

    Accurate Temporal Action Proposal Generation with Relation-Aware Pyramid Network

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    Accurate temporal action proposals play an important role in detecting actions from untrimmed videos. The existing approaches have difficulties in capturing global contextual information and simultaneously localizing actions with different durations. To this end, we propose a Relation-aware pyramid Network (RapNet) to generate highly accurate temporal action proposals. In RapNet, a novel relation-aware module is introduced to exploit bi-directional long-range relations between local features for context distilling. This embedded module enhances the RapNet in terms of its multi-granularity temporal proposal generation ability, given predefined anchor boxes. We further introduce a two-stage adjustment scheme to refine the proposal boundaries and measure their confidence in containing an action with snippet-level actionness. Extensive experiments on the challenging ActivityNet and THUMOS14 benchmarks demonstrate our RapNet generates superior accurate proposals over the existing state-of-the-art methods.Comment: accepted by AAAI-2

    In ovo serial skeletal muscle diffusion tractography of the developing chick embryo using DTI: feasibility and correlation with histology

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    Abstract Background Magnetic resonance imaging is a noninvasive method of evaluating embryonic development. Diffusion tensor imaging (DTI), based on the directional diffusivity of water molecules, is an established method of evaluating tissue structure. Yet embryonic motion degrades the in vivo acquisition of long-duration DTI. We used a dual-cooling technique to avoid motion artifact and aimed to investigate whether DTI can be used to monitor chick embryonic skeletal muscle development in ovo, and to investigate the correlation between quantitative DTI parameters fractional anisotropy (FA) and fiber length and quantitative histologic parameters fiber area percentage (FiberArea%) and limb length. Results From 84 normally developing chick embryos, 5 were randomly chosen each day from incubation days 5 to 18 and scanned using 3.0 Tesla magnetic resonance imaging. A dual-cooling technique is used before and during imaging. Eggs were cracked for making histological specimen after imaging. 3 eggs were serially imaged from days 5 to 18. We show that skeletal muscle fibers can be tracked in hind limb in DTI beginning with incubation day 8. Our data shows a good positive correlation between quantitative DTI and histologic parameters (FA vs FiberArea%: r= 0.943, p\u3c0.0001; Fiber_length vs Limb_length: r=0.974, p\u3c0.0001). The result of tracked fibers in DTI during incubation corresponds to the development of chick embryonic skeletal muscle as reported in the literature. Conclusion Diffusion tensor imaging can provide a noninvasive means of evaluating skeletal muscle development in ovo

    Research progress of biomass carbon materials as anode materials for potassium-ion batteries

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    Biochar materials have attracted people’s attention because of their environmental friendliness, abundant resources, and the use of waste resources for reuse. As a potassium-ion anode material, biomass char materials synthesized by different methods have broad application prospects. However, due to the problems of low initial magnification and limited potassium-storage capacity, it is necessary to improve the electrochemical performance through modifications, such as atomic doping. Atomic doping is an effective way to improve battery conductivity and potassium storage. In this paper, the synthesis method of biochar as an anode material for potassium-ion batteries and the influence of atomic doping on its modification in recent years are reviewed

    Application of remote online learning in oral histopathology teaching in China

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    The aim of this study was to investigate the application of remote learning and virtual microscopy in oral histopathology teaching, a unique experience in China. The oral histopathology teaching in Nanjing Medical University has been extraordinary. 98 third-year dental students of Grade 2016 took oral histopathology theoretical course face-to-face in 2019 (Traditional group). The 94 participants of Grade 2017 took online oral histopathology course using digital methods(E-Learning platform and Virtual Simulation Experiment Teaching Center for Dentistry) in 2020. During the practical laboratory sessions, the students in both Traditional group and Online group observed the same glass slides for morphological learning. A questionnaire survey explored students' attitudes towards the remote online learning. Results: The mean Theory test scores of the Online group (80.93±12.15) were significantly higher than those of the Traditional group (73.65±8.46) (P 85) of the Online group (54%) was also significantly higher than that of the Traditional group (15%) (P< 0.01). Furthermore, both remote learning and virtual microscopy courses were well accepted by students according to the questionnaire. This study found that remote learning and virtual technology have a positive impact on oral histopathology. The findings reveal that the application of remote online learning has enhanced oral histopathology teaching in China

    Electroacupuncture Improves Bladder and Bowel Function in Patients with Traumatic Spinal Cord Injury: Results from a Prospective Observational Study

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    In order to explore the effect of electroacupuncture (EA) for chronic bowel and bladder dysfunction after traumatic spinal cord injury, 14 patients were treated with electroacupuncture once a day, five times a week for the first four weeks, and once every other day, three times a week for the following four weeks. The patients were then followed up for six months. After treatment, four (4/14, 28.57%) patients resumed normal voiding; six (6/14, 42.86%) resumed normal voiding for no less than half of all micturition behaviors; four (4/14, 28.57%) required supplementary urination methods for higher than half of all micturition behaviors. These effects persisted during followup. Mean postvoid RUV decreased by 190.29±101.87 mL (P<0.01) after treatment and by 198.86±112.18 mL (P<0.01) during followup. Patients’ weekly urinary incontinence frequency decreased 7.14±46.34 times/week (P=0.036) after treatment and decreased 49.86±44.38 times/week during followup. After treatment, four (4/14, 28.57%) patients resumed normal bowel movements (P=0.025); five (5/14, 35.71%) reduced the dependence on supplementary defecation methods; five (5/14, 35.71%) had no changes. In patients with chronic bowel and bladder dysfunction after traumatic SCI, EA may provide a valuable alternative tool in improving patients’ self-controlled bowel and bladder functions with minimal side effects

    In Ovo Monitoring of Smooth Muscle Fiber Development in the Chick Embryo: Diffusion Tensor Imaging with Histologic Correlation

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    , and to determine the correlation between histologically-derived muscle fiber fraction, day of incubation and diffusion tensor imaging fractional anisotropy values and length of tracked fibers.From a set of 82 normally developing fertile chicken eggs, 5 eggs were randomly chosen each day from incubation days 5 to 18 and cooled using a dual-cooling technique prior to and during magnetic resonance imaging at 3.0 Tesla. Smooth muscle fibers of the gizzard were tracked using region of interests placed over the gizzard. Following imaging, the egg was cracked and the embryo was fixated and sectioned, and a micrograph most closely corresponding to the acquired magnetic resonance image was made. Smooth muscle fiber fraction was determined using an automated computer algorithm. development of smooth muscle tissue
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