154 research outputs found

    A Hybrid Intelligent Early Warning System for Predicting Economic Crises: The Case of China

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    This paper combines artificial neural networks (ANN), fuzzy optimization and time-series econometric models in one unified framework to form a hybrid intelligent early warning system (EWS) for predicting economic crises. Using quarterly data on 12 macroeconomic and financial variables for the Chinese economy during 1999 and 2008, the paper finds that the hybrid model possesses strong predictive power and the likelihood of economic crises in China during 2009 and 2010 remains high.Computational intelligence; artificial neural networks; fuzzy optimization; early warning system; economic crises

    Environmental regulation and sectoral disparity in labor demand: evidence from a quasi-natural experiment in China

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    The trade-off between environmental regulation and job creation has been a dilemma for policymakers in the past decades. Exploiting the enterprise-level sample data, we conduct a difference- in-difference-in-differences (DDD) specification to estimate the overall effect of China’s Two Control Zones (TCZ) policy on labor demand, measured as the number of enterprise-level employees. We find that the industrial enterprises in TCZ cities, where the TCZ policy has been implemented after 1998, employed fewer workers in more polluting industries. Furthermore, these employment effects are very heterogeneous among different enterprise ownerships and control zones. The TCZ policy significantly decreased the labor demand in private enterprises or those located in the Acid Rain Control Zones (ARCZ) but had little impact on their stateowned and foreign-invested counterparts or those located in the Sulfur Dioxide Pollution Control Zones (SPCZ)

    A Hybrid Intelligent Early Warning System for Predicting Economic Crises: The Case of China

    Get PDF
    This paper combines artificial neural networks (ANN), fuzzy optimization and time-series econometric models in one unified framework to form a hybrid intelligent early warning system (EWS) for predicting economic crises. Using quarterly data on 12 macroeconomic and financial variables for the Chinese economy during 1999 and 2008, the paper finds that the hybrid model possesses strong predictive power and the likelihood of economic crises in China during 2009 and 2010 remains high

    Enhanced Management of Personal Astronomical Data with FITSManager

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    Although the roles of data centers and computing centers are becoming more and more important, and on-line research is becoming the mainstream for astronomy, individual research based on locally hosted data is still very common. With the increase of personal storage capacity, it is easy to find hundreds to thousands of FITS files in the personal computer of an astrophysicist. Because Flexible Image Transport System (FITS) is a professional data format initiated by astronomers and used mainly in the small community, data management toolkits for FITS files are very few. Astronomers need a powerful tool to help them manage their local astronomical data. Although Virtual Observatory (VO) is a network oriented astronomical research environment, its applications and related technologies provide useful solutions to enhance the management and utilization of astronomical data hosted in an astronomer's personal computer. FITSManager is such a tool to provide astronomers an efficient management and utilization of their local data, bringing VO to astronomers in a seamless and transparent way. FITSManager provides fruitful functions for FITS file management, like thumbnail, preview, type dependent icons, header keyword indexing and search, collaborated working with other tools and online services, and so on. The development of the FITSManager is an effort to fill the gap between management and analysis of astronomical data.Comment: 12 pages, 9 figures, Accepted for publication in New Astronom

    Image-based Visual Servo Control for Aerial Manipulation Using a Fully-Actuated UAV

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    Using Unmanned Aerial Vehicles (UAVs) to perform high-altitude manipulation tasks beyond just passive visual application can reduce the time, cost, and risk of human workers. Prior research on aerial manipulation has relied on either ground truth state estimate or GPS/total station with some Simultaneous Localization and Mapping (SLAM) algorithms, which may not be practical for many applications close to infrastructure with degraded GPS signal or featureless environments. Visual servo can avoid the need to estimate robot pose. Existing works on visual servo for aerial manipulation either address solely end-effector position control or rely on precise velocity measurement and pre-defined visual visual marker with known pattern. Furthermore, most of previous work used under-actuated UAVs, resulting in complicated mechanical and hence control design for the end-effector. This paper develops an image-based visual servo control strategy for bridge maintenance using a fully-actuated UAV. The main components are (1) a visual line detection and tracking system, (2) a hybrid impedance force and motion control system. Our approach does not rely on either robot pose/velocity estimation from an external localization system or pre-defined visual markers. The complexity of the mechanical system and controller architecture is also minimized due to the fully-actuated nature. Experiments show that the system can effectively execute motion tracking and force holding using only the visual guidance for the bridge painting. To the best of our knowledge, this is one of the first studies on aerial manipulation using visual servo that is capable of achieving both motion and force control without the need of external pose/velocity information or pre-defined visual guidance.Comment: Accepted by 2023 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS
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