471 research outputs found
Integrated Face Analytics Networks through Cross-Dataset Hybrid Training
Face analytics benefits many multimedia applications. It consists of a number
of tasks, such as facial emotion recognition and face parsing, and most
existing approaches generally treat these tasks independently, which limits
their deployment in real scenarios. In this paper we propose an integrated Face
Analytics Network (iFAN), which is able to perform multiple tasks jointly for
face analytics with a novel carefully designed network architecture to fully
facilitate the informative interaction among different tasks. The proposed
integrated network explicitly models the interactions between tasks so that the
correlations between tasks can be fully exploited for performance boost. In
addition, to solve the bottleneck of the absence of datasets with comprehensive
training data for various tasks, we propose a novel cross-dataset hybrid
training strategy. It allows "plug-in and play" of multiple datasets annotated
for different tasks without the requirement of a fully labeled common dataset
for all the tasks. We experimentally show that the proposed iFAN achieves
state-of-the-art performance on multiple face analytics tasks using a single
integrated model. Specifically, iFAN achieves an overall F-score of 91.15% on
the Helen dataset for face parsing, a normalized mean error of 5.81% on the
MTFL dataset for facial landmark localization and an accuracy of 45.73% on the
BNU dataset for emotion recognition with a single model.Comment: 10 page
Charging and Discharging Mechanism of Polyimide under Electron Irradiation and High Voltage
Polyimide has been widely used as insulating and structural materials in spacecraft due to its excellent electrical, thermal and mechanical properties. However, its charging and discharging problem in harsh space environment has been a major limit to the development of high-voltage and high-power spacecraft. In this chapter, charging and discharging phenomena of dielectric materials under electron irradiation environment were presented. First, the electrical properties of polyimide consisting of dielectric properties, trap properties, conductivity and electrical breakdown properties were investigated, which have great influences on charging and discharging characteristics. Then, a surface charging model under relatively low-energy electron irradiation was proposed for polyimide, based on the synergistic effects of electron movement above surface and charge transport in surface layer. The DC surface flashover of polyimide under electron irradiation with different energies, fluxes and incident angles was investigated. Furthermore, a deep charging model under high-energy electron irradiation with the Fluence Model for Internal Charging (FLUMIC) spectrum was established. The effects of electron flux enhancement and operating voltage on charging characteristics were discussed in different grounding modes. It indicates that the processes of discharging under electron irradiation have a close link with the charge transport characteristics of polyimide
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Reinforcement learning control for a robotic manipulator with unknown deadzone
In this paper, an actor critic neural network control is developed for a robotic manipulator. Both system uncertainties and unknown deadzone are considered in the tracking control design. Stability of the closed-loop system is analyzed via the Lyapunov’s direct method. The critic neural network is used to estimate the cost-to-go and the actor neural network is used to make the cost-to-go converge. Simulation studies are conducted to examine the effectiveness of the proposed actor critic neural network control
Space charge modulated electrical breakdown
Electrical breakdown is one of the most important physical phenomena in electrical and electronic engineering. Since the early 20th century, many theories and models of electrical breakdown have been proposed, but the origin of one key issue, that the explanation for dc breakdown strength being twice or higher than ac breakdown strength in insulating materials, remains unclear. Here, by employing a bipolar charge transport model, we investigate the space charge dynamics in both dc and ac breakdown processes. We demonstrate the differences in charge accumulations under both dc and ac stresses and estimate the breakdown strength, which is modulated by the electric field distortion induced by space charge. It is concluded that dc breakdown initializes in the bulk whereas ac breakdown initializes in the vicinity of the sample-electrode interface. Compared with dc breakdown, the lower breakdown strength under ac stress and the decreasing breakdown strength with an increase in applied frequency, are both attributed to the electric field distortion induced by space charges located in the vicinity of the electrodes
The Synthesis of QADMAA and its Application to the Solid Phase Extraction and Spectrophotometric Determination of Cobalt
In this paper, the synthesis of a new chromogenic reagent, 2-(2-quinolylazo)-5-dimethylaminoaniline (QADMAA), is reported. A sensitive, selective and rapid method for the determination of cobalt based on the rapid reaction of cobalt(II) with QADMAA and the solid phase extraction of the Co(II)-QADMAAchelate withC18 membrane disks was developed. In the presence of a pH=5.5 buffer solution and a cetyl trimethylammonium bromide (CTMAB) medium, QADMAA reacts with cobalt to form a violet complex with a molar ratio of 1:2 (cobalt to QADMAA). This chelate was enriched by solid phase extraction with C18 membrane disks and an enrichment factor of 50 was obtained. The molar absorptivity of the chelate is 1.32x105 L mol-1 cm-1 at 616 nm in the measured solution. Beer's law is obeyed in the range of 0.01~0.6 mg mL-1. The relative standard deviation for eleven replicate sample at the 0.01 mg mL-1 level is 1.35%. The detection limit reached 0.02 mg L-1 in the original samples. This method was applied with good results to the determination of cobalt in environmental samples. Keywords: 2-(2-Quinolylazo)-5-dimethylaminoaniline Cobalt Spectrophotometry Solid phase extraction South African Journal of Chemistry Vol.57 2004: 28-3
Marsdenia tenacissima extract alters crucial metabolites in cancer, determined by 1H NMR based metabolomics approach
Altered metabolites level in the biosystems, is the potential cause of cancer, the primary reason of alteration of metabolism is change in nutrient consumption and waste excretion, as a result genetic mutation leads to cancer initiation and progression. Aberration of specific metabolites such as fumarate, succinate, 2-hydroxyglutarate may alter cell signaling. We collected liver and kidney samples and prepared for 1 H NMR analysis, then executed NMR spectroscopy. We used a set of domestic R scripts to perform an unsupervised principal component analysis (PCA) and a supervised orthogonal signal correction partial least-squares discriminant analysis (OSC-PLS-DA). It signifies class discrimination for getting a clear separation, whereas PCA scores plot signifies the model group kept further away from the control group than drug group on the horizontal axis. In another PCA scores plots, most parts of the control group was overlapping with the drug group but was distant from the model group. Marsdenia tenacissima extract (MTE) (Chines name: Xiao-Ai-Ping, XAP) modulates level of crucial metabolites such as fumarate, lactate, succinate, determined by 1 H NMR spectroscopy and their altered level contributes major role in cancer
Utilization of ultra-fine dredged sand from the Yangtze River in alkali-activated slag/fly ash mortars: mechanical properties, drying shrinkage and microstructure
The ultra-fine dredged sand (DS) from the lower reaches of the Yangtze River is a large amount of solid waste with the potential to be recycled and applied as a replacement for fine aggregate. This article discussed the utilization of dredged sand by producing alkali activated materials (AAMs). The chemical and physical characteristics of the DS were analyzed. The effect of the DS on durability and mechanical characteristics of the alkali activated slag/fly materials were studied with different precursor systems. From the results, it was found that the addition of DS improved the 28 d strength and even 56 d strength. The 25% DS content increased the compressive strength of both slag rich and fly ash (FA) rich AAMs by about 5%, and the microstructure showed a denser matrix at this content. However, excessive DS can cause a decrease in flowability, early compressive strength and a decline in the compactness of the matrix. Adding an appropriate amount of DS can control the drying shrinkage. The 25% DS content has an inhibitory effect on the shrinkage development of slag rich mortar, while the similar effect on FA rich mortar appears at a content of over 50%. The adoption of DS addition to produce AAMs improves the ecological benefits of concrete engineering projects on the Yangtze River coast.Acknowledged financial supports include the National Key R&D Program of China (Grant No. 2021YFB2600200), the Fundamental Research Funds for the Central Universities (Grant No. B230205017), State Key Laboratory of High-Performance Civil Engineering Materials (Grant NO. 2019CEM002), and National Natural Science Foundation of China (Grant No. 51979090).Peer ReviewedPostprint (published version
Polymer Electret Improves the Performance of the Oxygen-Doped Organic Field-Effect Transistors
Chemical doping is widely used in the electronic devices. In p-type semiconductor thin films, oxygen doping fills the hole traps and increases hole concentrations, improving the performance of the organic field-effect transistors (OFETs). Due to the low ionization potential for p-type semiconductors, the superfluous holes induced by the oxygen doping degrades the OFETs off-state leakage performance. On the other hand, for p-type semiconductors with high ionization potential (up to 5.5-6.0 eV), the limited oxidation of oxygen is hard to achieve satisfactory doping concentrations to fill the trap states. This refers to the well-known intrinsic incompatibility between the oxygen doping and high-performance OFETs. Herein, a novel strategy is introduced to overcome the incompatibility and achieve high-performance OFETs by using the structural polymer electret. That is, moderate hole concentrations induced by low-pressure (30 Pa) oxygen plasma fill the hole traps within semiconductor. And the built-in field resulted from polymer electret accumulates the holes inside semiconductor near the semiconductor/electret interface, thus improving the OFETs performance. Using a model organic semiconductor with high ionization potential-2,7-didodecyl[1]benzothieno [3,2-b][1]benzothiophene (C12-BTBT) as an example, the high-performance OFETs with field-effect mobility (μFET) of 3.5 cm 2 V -1 s -1 , subthreshold-swing (SS) of 110 mV decade -1 , on-off ratio of 10 4 , and widely-tunable threshold voltage (V t ) are realized at a low voltage below 2 V in the open air
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