697 research outputs found

    Dual-track interest rates and the conduct of monetary policy in China

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    China has a dual-track interest-rate system: bank deposit and lending rates are regulated while money and bond rates are market-determined. The central bank also imposes an indicative target, which may not be binding at all times, for total credit in the banking system. We develop and calibrate a theoretical model to illustrate the conduct of monetary policy within the framework of dual-track interest rates and a juxtaposition of price- and quantity-based policy instruments. We model the transmission of monetary policy instruments to market interest rates, which, together with the quantitative credit target in the banking system, ultimately are the means by which monetary policy affects the real economy. The model shows that market interest rates are most sensitive to changes in the benchmark deposit interest rates, significantly responsive to changes in the reserve requirements, but not particularly reactive to open market operations. These theoretical results are verified and supported by both linear and GARCH models using daily money and bond market data. Overall, the findings of this study help us to understand why the central bank conducts monetary policy in China the way it does, using a combination of price and quantitative instruments with differing degrees of potency in terms of their influence on the cost of credit.monetary policy; People’s Bank of China; dual-track interest rates; interest rate liberalization

    学会抄録

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    Details for the selection of physicochemical properties from AAIndex database. (DOC 31 kb

    A063: Electroencephalogram (EEG) Signal Analysis for College Students\u27 Attention and Meditation Level in Yoga Courses

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    PURPOSE: Yoga is associated with psychological and physiological benefits, including relaxation and increased attention. Electroencephalograms (EEG) signals reflect the electrical activity of the brain and transformed Alpha and Beta brainwaves into meditation and attention values. This study primarily aimed to measure college students’ attention and meditation level in yoga courses. The secondary aim was to explore yoga’s effect on students’ cognitive ability. METHODS: The study selected two yoga classes in the first semester of 2023 in an academic university in China. Using convenience sampling methods, 16 college students who attended yoga courses voluntarily participated in this study. All learning phases, teaching content, and course time were maintained the same between the two classes during the study. Selected yoga poses included one previously learned pose and seven new poses. Each lesson lasted 90 min with 30-40 min review phase and 40-45 min in the teaching phase. EEG signals were processed during the review phase and the teaching phase in yoga courses. Collected data were analyzed by one-way ANOVA tests using R 4.3.1. RESULTS: For the attention level, EEG signal in the review phase was (mean ± standard deviation) 48.12±1.40, while that in the teaching phase was 46.24±2.57. For meditation, EEG signal in the review phase was 50.05±3.41, while that in the teaching phase was 49.37±4.85. The attention level in the teaching phase was significantly lower than that in the review phase (F(1,19)=4.68, p \u3c 0.05, η2=0.2). In contrast, for the meditation level, there was no significant difference between the teaching phase and the review phase (F(1,19)=0.15, p=0.7, η2=0.008). Among different yoga poses, there was no significant difference observed in either attention or meditation. CONCLUSION: Students’ attention was significantly higher in the review phase than that in the teaching phase. As the time of two phases was relatively the same, students may lose their attention when learning new poses. To enhance class efficiency, the teaching phase is recommended to be placed before the review phase, as students may have more energy at the beginning of the class. In addition, including a review practice during the teaching phase can enhance students’ attention and achieve better effect

    Adaptive Testing for Connected and Automated Vehicles with Sparse Control Variates in Overtaking Scenarios

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    Testing and evaluation is a critical step in the development and deployment of connected and automated vehicles (CAVs). Due to the black-box property and various types of CAVs, how to test and evaluate CAVs adaptively remains a major challenge. Many approaches have been proposed to adaptively generate testing scenarios during the testing process. However, most existing approaches cannot be applied to complex scenarios, where the variables needed to define such scenarios are high dimensional. Towards filling this gap, the adaptive testing with sparse control variates method is proposed in this paper. Instead of adaptively generating testing scenarios, our approach evaluates CAVs' performances by adaptively utilizing the testing results. Specifically, each testing result is adjusted using multiple linear regression techniques based on control variates. As the regression coefficients can be adaptively optimized for the CAV under test, using the adjusted results can reduce the estimation variance, compared with using the testing results directly. To overcome the high dimensionality challenge, sparse control variates are utilized only for the critical variables of testing scenarios. To validate the proposed method, the high-dimensional overtaking scenarios are investigated, and the results demonstrate that our approach can further accelerate the evaluation process by about 30 times

    Adaptive Safety Evaluation for Connected and Automated Vehicles with Sparse Control Variates

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    Safety performance evaluation is critical for developing and deploying connected and automated vehicles (CAVs). One prevailing way is to design testing scenarios using prior knowledge of CAVs, test CAVs in these scenarios, and then evaluate their safety performances. However, significant differences between CAVs and prior knowledge could severely reduce the evaluation efficiency. Towards addressing this issue, most existing studies focus on the adaptive design of testing scenarios during the CAV testing process, but so far they cannot be applied to high-dimensional scenarios. In this paper, we focus on the adaptive safety performance evaluation by leveraging the testing results, after the CAV testing process. It can significantly improve the evaluation efficiency and be applied to high-dimensional scenarios. Specifically, instead of directly evaluating the unknown quantity (e.g., crash rates) of CAV safety performances, we evaluate the differences between the unknown quantity and known quantity (i.e., control variates). By leveraging the testing results, the control variates could be well designed and optimized such that the differences are close to zero, so the evaluation variance could be dramatically reduced for different CAVs. To handle the high-dimensional scenarios, we propose the sparse control variates method, where the control variates are designed only for the sparse and critical variables of scenarios. According to the number of critical variables in each scenario, the control variates are stratified into strata and optimized within each stratum using multiple linear regression techniques. We justify the proposed method's effectiveness by rigorous theoretical analysis and empirical study of high-dimensional overtaking scenarios

    Vapor pressure deficit and temperature variability drive future changes to carbon sink stability in China’s terrestrial ecosystems

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    The stability of future carbon sinks is crucial for accurately predicting the global carbon cycle. However, the future dynamics and stability of carbon sinks remain largely unknown, especially in China, a significant global carbon sink region. Here, we examined the dynamics and stability of carbon sinks in China’s terrestrial ecosystems from 2015 to 2,100 under two CMIP6 scenarios (SSP245 and SSP585), using XGBoost and SHAP models to quantify the impact of climatic drivers on carbon sink stability. China’s future terrestrial ecosystems will act as a “carbon sink” (0.27–0.33 PgC/yr), with an initial increase that levels off over time. Although the carbon sink capacity increases, its stability does not consistently improve. Specifically, the stability of carbon sinks in future China’s terrestrial ecosystems transitions from strengthening to weakening, primarily occurring in areas with higher carbon sink capacity. Further analysis revealed that atmospheric vapor pressure deficit (VPD) and temperature (Tas) are the two primary factors influencing carbon sink stability, with significant differences in their impacts across different scenarios. Under the SSP245 scenario, variations in VPD (VPD.CV) regulate water availability through stomatal conductance, making it the key driver of changes in carbon sink stability. In contrast, under the SSP585 scenario, although VPD.CV still plays an important role, temperature variability (Tas.CV) becomes the dominant factor, with more frequent extreme climate events exacerbating carbon cycle instability. The study highlights the differences in driving factors of carbon sink stability under different scenarios and stresses the importance of considering these differences, along with the scale and stability of carbon sinks, when developing long-term carbon management policies to effectively support carbon neutrality goals

    Heparinization and hybridization of electrospun tubular graft for improved endothelialization and anticoagulation

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    Supplementary data to this article can be found online at https://doi.org/10.1016/j.msec.2020.111861.Constructing biomimetic structure and immobilizing antithrombus factors are two effective methods to ensure rapid endothelialization and long-term anticoagulation for small-diameter vascular grafts. However, few literatures are available regarding simultaneous implementation of these two strategies. Herein, a nano-micro-fibrous biomimetic graft with a heparin coating was prepared via a step-by-step in situ biosynthesis method to improve potential endothelialization and anticoagulation. The 4-mm-diameter tubular graft consists of electrospun cellulose acetate (CA) microfibers and entangled bacterial nanocellulose (BNC) nanofibers with heparin coating on dual fibers. The hybridized and heparinized graft possesses suitable pore structure that facilitates endothelia cells adhesion and proliferation but prevents infiltration of fibrous tissue and blood leakage. In addition, it shows higher mechanical properties than those of bare CA and hybridized CA/BNC grafts, which match well with native blood vessels. Moreover, this dually modified graft exhibits improved blood compatibility and endothelialization over the counterparts without hybridization or heparinization according to the testing results of platelet adhesion, cell morphology, and protein expression of von Willebrand Factor. This novel graft with dual modifications shows promising as a new small-diameter vascular graft. This study provides a guidance for promoting endothelialization and blood compatibility by dual modifications of biomimetic structure and immobilized bioactive molecules.This work was supported by the National Natural Science Foundation of China (grant nos. 51973058 and 31870963), the Key Research and Development Program of Jiangxi Province (No. 20192ACB80008), and the Key Project of Natural Science Foundation of Jiangxi Province (20202ACBL204013).info:eu-repo/semantics/publishedVersio

    Late-Quaternary paleoearthquakes along the Liulengshan Fault on the northern Shanxi Rift system

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    The Liulengshan Fault (LLSF), which lies on the northeastern edge of the Ordos Plateau, is a controlling boundary fault in the northern part of the Shanxi Rift system (SRS). The displaced landforms show that the fault has undergone strong and frequent late-Quaternary seismic activities. In 1989 and 1991, two moderate–strong earthquake swarms (Ms=6.1 and Ms=5.8) successively occurred in the LLSF, and GPS velocity shows that the areas are extending at around 1–2 mm/a. However, there is no surface-rupturing earthquake reported on the LLSF in historical records. Thus, the study of paleoseismic history and rupture behavior of paleoearthquakes in late-Quaternary on the LLSF is of fundamental importance for understanding the future seismic risk of this fault. To solve these problems, we conducted paleoseismological trench excavations at two sites on the LLSF to establish its paleoearthquake history. On the basis of the field geological survey and interpretation of high-precision topographic data, we carried out large-scale fault mapping and excavated two trenches in Xujiabao and Luofengwa across the LLSF. Then, four events in the Xujiabao trench and three events in the Luofengwa trench are identified. Finally, combined with radiocarbon dating (C14), optically stimulated luminescence (OSL) and OxCal modeling, we constrained the ages of these events. Together with the previous results of paleoseismology in Yin et al. (1997), we consider that different segments of the LLSF may rupture together at the same time. Therefore, a total of six paleoearthquake events since late-Quaternary have been finally confirmed at 44,151–30881a, 40,163-28045a, 28,233-19215a, 16,742-12915a, 12,788-8252a, and 8203–2300a BP. According to the empirical relationships between moment magnitude and rupture length, the best estimated magnitude is inferred to be in the range between Mw 6.9 and Mw 7.7. Considering the strong late-Quaternary activity and a long earthquake elapsed time, we propose that the LLSF might have a high seismic hazard potential in the near future
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