4,346 research outputs found

    Crowdsourcing for Sustainable Urban Logistics: Exploring the Factors Influencing Crowd Workers’ Participative Behavior

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    With crowd logistics becoming a crucial part of the last-mile delivery challenge in many cities, continued participation of crowd workers has become an essential issue affecting the growth of the crowd logistics platform. Understanding how people are motivated to continue their participation in crowd logistics can provide some clarity as to what policies and measures should be undertaken by the industry to support its further growth. Using the Push-Pull-Mooring (PPM) theory, we developed a research model to explain the factors influencing crowd workers' participative behavior. Survey data from 455 crowd workers were analyzed using SmartPLS3.0 software. The results show monetary rewards and trust have a significant positive impact on the willingness of crowd workers to continue participating in crowd logistics, while work enjoyment from previous work and entry barriers for work have a significant negative impact. Trust plays an intermediary role between monetary incentives and crowd workers' willingness to continue participating. Based on the findings of this study, we recommend that crowd logistics platforms should offer reasonable monetary incentives and keep these under constant review, build a high degree of trust and cooperation with their crowd workers, and initiate activities geared towards promoting satisfaction at work

    Development of a Portable Single Photon Ionization-Photoelectron Ionization Time-of-Flight Mass Spectrometer

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    A vacuum ultraviolet lamp based single photon ionization- (SPI-) photoelectron ionization (PEI) portable reflecting time-of-flight mass spectrometer (TOFMS) was designed for online monitoring gas samples. It has a dual mode ionization source: SPI for analyte with ionization energy (IE) below 10.6 eV and PEI for IE higher than 10.6 eV. Two kinds of sampling inlets, a capillary inlet and a membrane inlet, are utilized for high concentration and trace volatile organic compounds, respectively. A mass resolution of 1100 at m/z 64 has been obtained with a total size of 40 × 31 × 29 cm, the weight is 27 kg, and the power consumption is only 70 W. A mixture of benzene, toluene, and xylene (BTX), SO2, and discharging products of SF6 were used to test its performance, and the result showed that the limit of quantitation for BTX is as low as 5 ppbv (S/N = 10 : 1) with linear dynamic ranges greater than four orders of magnitude. The portable TOFMS was also evaluated by analyzing volatile organic compounds from wine and decomposition products of SF6 inside of a gas-insulated switchgear

    Think Twice: A Human-like Two-stage Conversational Agent for Emotional Response Generation

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    Towards human-like dialogue systems, current emotional dialogue approaches jointly model emotion and semantics with a unified neural network. This strategy tends to generate safe responses due to the mutual restriction between emotion and semantics, and requires rare emotion-annotated large-scale dialogue corpus. Inspired by the "think twice" behavior in human dialogue, we propose a two-stage conversational agent for the generation of emotional dialogue. Firstly, a dialogue model trained without the emotion-annotated dialogue corpus generates a prototype response that meets the contextual semantics. Secondly, the first-stage prototype is modified by a controllable emotion refiner with the empathy hypothesis. Experimental results on the DailyDialog and EmpatheticDialogues datasets demonstrate that the proposed conversational outperforms the comparison models in emotion generation and maintains the semantic performance in automatic and human evaluations.Comment: Accepted to AAMAS202

    Effects and mechanism of anti-VEGF assisted PPV in the treatment of proliferative retinopathy

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    AIM: To investigate the effects and mechanism of anti-vascular endothelial growth factor(VEGF)assisted pars plana vitrectomy(PPV)in the treatment of proliferative diabetic retinopathy(PDR).METHODS: A total of 92 patients(92 eyes)with PDR treated by PPV were divided into the simple PPV group(41 patients with 41 affected eyes)and the combined treatment group(51 patients with 51 affected eyes)according to whether the patient underwent intravitreal injection of Ranibizumab(IVR). The combined treatment group was treated with IVR at 5-7d before PPV. The surgical time, times of electrocoagulation, silicone oil filling rate, the incidence of postoperative complications, LogMAR BCVA of affected eyes, levels of VEGF and pigment epithelium derived factor(PEDF)in aqueous humor and vitreous body were compared between the two groups. RESULTS: The surgical time was shorter, the times of electrocoagulation was less, the silicone oil filling rate and the incidence rates of iatrogenic retinal hole and vitreous body hematocele were lower in the combined treatment group than in the simple PPV group(PPPCONCLUSION: IVR combined with PPV can reduce the perioperative levels of VEGF and PEDF, reduce the times of electrocoagulation and the incidence of iatrogenic retinal hole and vitreous body hematocele, and improve the visual acuity of patients with PDR

    Exploring EEG Features in Cross-Subject Emotion Recognition

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    Recognizing cross-subject emotions based on brain imaging data, e.g., EEG, has always been difficult due to the poor generalizability of features across subjects. Thus, systematically exploring the ability of different EEG features to identify emotional information across subjects is crucial. Prior related work has explored this question based only on one or two kinds of features, and different findings and conclusions have been presented. In this work, we aim at a more comprehensive investigation on this question with a wider range of feature types, including 18 kinds of linear and non-linear EEG features. The effectiveness of these features was examined on two publicly accessible datasets, namely, the dataset for emotion analysis using physiological signals (DEAP) and the SJTU emotion EEG dataset (SEED). We adopted the support vector machine (SVM) approach and the "leave-one-subject-out" verification strategy to evaluate recognition performance. Using automatic feature selection methods, the highest mean recognition accuracy of 59.06% (AUC = 0.605) on the DEAP dataset and of 83.33% (AUC = 0.904) on the SEED dataset were reached. Furthermore, using manually operated feature selection on the SEED dataset, we explored the importance of different EEG features in cross-subject emotion recognition from multiple perspectives, including different channels, brain regions, rhythms, and feature types. For example, we found that the Hjorth parameter of mobility in the beta rhythm achieved the best mean recognition accuracy compared to the other features. Through a pilot correlation analysis, we further examined the highly correlated features, for a better understanding of the implications hidden in those features that allow for differentiating cross-subject emotions. Various remarkable observations have been made. The results of this paper validate the possibility of exploring robust EEG features in cross-subject emotion recognition

    4-[5-(4-Pyrid­yl)-1,3,4-oxadiazol-2-yl]pyridine N-oxide–isophthalic acid (1/1)

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    The title compound, C12H8N4O2·C8H6O4, was synthesized from 4-[5-(4-pyrid­yl)-1,3,4-oxadiazol-2-yl]pyridine N-oxide and isophthalic acid. The two mol­ecules are linked through O—H⋯O and O—H⋯N hydrogen bonds. Weak intra­molecular π–π inter­actions between the two hydrogen-bonded chains result in the formation a one-dimensional supra­molecular curved tape (the face-to-face distance between the pyridine N-oxide ring and the benzene ring is 3.7 Å)

    Effects of electron acceptors on CH4 emission in alpine wetlands

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    Alpine wetlands are an important source of methane (CH4) and play a key role in the global carbon cycle. Their CH4 emissions largely depend on microbial CH4 production and oxidation processes that involve external electron acceptors. Seasonal precipitation drives redox cycles of humic acids (HAs), iron oxide and sulfur species, which will in turn affect CH4 production and oxidation. To investigate the effects of electron acceptors on CH4 emissions, soil samples from a typical alpine wetland on the Tibetan Plateau were incubated with the addition of ferrihydrite (HFO), HAs, sodium sulfate (SO42-) or combinations (HAs-HFO, HAs-SO42- and HAs-HFO-SO42-). During long-term anaerobic incubation, CH4 concentrations showed similar trends, increasing rapidly from 0 to 60 days, decreasing from 60 to 240 days, and finally slowly increasing again after 240 days, in all treatments except the sterilised control. Thus, the incubation period was divided into the production, consumption and reproduction phases. The addition of HFO, HAs or HAs-containing electron acceptors promoted the rates of both production and consumption of CH4, increasing the production potential of CH4 by 65–100 % and the oxidation potential of CH4 by 58–115 %. On the other hand, SO42- inhibited the production and consumption of CH4, reducing the production potential by 35 % and the oxidation potential by 50 %. Electron acceptors such as HFO, HAs and SO42- play important roles in CH4 emissions. HAs are the dominant factor affecting CH4 emissions in alpine wetlands. From a broader ecological perspective, organic and inorganic electron acceptors play a key role in CH4 production and oxidation under anaerobic conditions, influencing CH4 emissions from alpine wetlands

    Constraining GRB Initial Lorentz Factor with the Afterglow Onset Feature and Discovery of a Tight Gamma_0-E_iso Correlation

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    The onset of GRB afterglow is characterized by a smooth bump in the early afterglow lightcurve. We make an extensive search for such a feature. Twenty optically selected GRBs and 12 X-ray selected GRBs are found, among which 17 optically selected GRBs and 2 X-ray-selected GRBs have redshift measurements. We fit the lightcurves with a smooth broken power-law and measure the temporal characteristic timescales of the bumps at FWHM. Strong mutual correlations among these timescales are found, and a dimmer and broader bump tends to peak at a later peak time. The ratio of rising to decaying timescales is almost universal among bursts, but the ratio of the rising time to the peak time varies from 0.3~1. The E_iso is tightly correlated with the peak luminosity and the peak time of the bump in the burst frame. Assuming that the bumps signal the deceleration of the GRB fireballs in a constant density medium, we calculate the initial Lorentz factor (Gamma_0) and the deceleration radius (R_dec) of the GRBs in the optical-selected sample. It is found that Gamma_0 are typically a few hundreds, and the typical deceleration radius is R_dec~10^{17} cm. More intriguingly, a tight correlation between the Gamma_0 and E_iso is found, namely Gamma_0 ~ 195 E_iso, 52}^{0.27} (satisfied for both the optical and X-ray z-known samples). It is helpful to understand GRB physics, and may serve as an indicator of Gamma_0. We find that the early bright X-rays are usually dominated by a different component from the external shock emission, but occasionally (for one case) an achromatic deceleration feature is observed. Components in X-rays would contribute to the diversity of the observed X-ray lightcurves (abridge).Comment: 15 pages, including 4 tables and 7 figures, Submitted to Ap

    Pseudoscalar Higgs boson production associated with a single bottom quark at hadron colliders

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    We compute the complete next-to-leading order (NLO) SUSY-QCD corrections for the associated production of a pseudoscalar Higgs boson with a bottom quark via bottom-gluon fusion at the CERN Large Hadron Collider (LHC) and the Fermilab Tevatron. We find that the NLO QCD correction in the MSSM reaches 4040%\sim50% at the LHC and 4545%\sim80% at the Tevatron in our chosen parameter space
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