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Data-driven Optimal Control strategy for Virtual synchronous Generator via Deep Reinforcement learning Approach

Journal of Modern Power systems and Clean Energy 2021年第4期9卷 919-929页

作者： Yushuai li wei Gao weihang Yan shuo Huang Rui Wang Vahan Gevorgian david Wenzhong Gao Department of Electrical and Computer Engineering University of DenverDenverCO 80208USA school of Information science and Engineering Northeastern UniversityShenyangLiaoning110004China National Renewable Energy laboratory GoldenUSA

This paper aims at developing a data-driven optimal control strategy for virtual synchronous generator (VsG) in the scenario where no expert knowledge or requirement for system model is available. Firstly, the optimal and adaptive control problem for VsG is transformed into a reinforcement learning task. specifically, the control variables, i.e., virtual inertia and damping factor, are defined as the actions. Meanwhile, the active power output, angular frequency and its derivative are considered as the observations. Moreover, the reward mechanism is designed based on three preset characteristic functions to quantify the control targets: ① maintaining the deviation of angular frequency within special limits;② preserving well-damped oscillations for both the angular frequency and active power output;③ obtaining slow frequency drop in the transient process. Next, to maximize the cumulative rewards, a decentralized deep policy gradient algorithm, which features model-free and faster convergence, is developed and employed to find the optimal control policy. With this effort, a data-driven adaptive VsG controller can be obtained. By using the proposed controller, the inverter-based distributed generator can adaptively adjust its control variables based on current observations to fulfill the expected targets in model-free fashion. Finally, simulation results validate the feasibility and effectiveness of the proposed approach.

关键词： Adaptive control virtual synchronous generator(VsG) reinforcement learning deep learning

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Discharge-stage Relationship on Urban streams Evaluated at UsGs Gauging stations,***,Missouri

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Journal of Earth science 2020年第6期31卷 1133-1141页

作者： Robert E.Criss david l.Nelson Department of Earth and Planetary sciences Washington UniversitySt.Louis MO 63130USA Columbia Cir Pasadena CA 91105USA

Extensive UsGs data tables and detailed,1 m2 li DAR surveys are used to determine the optimal power n that relates discharge(Q)to stage(h*)above channel bottom(ho)at 39 gauging stations on small streams in the ***,Missouri area,all of which have catchments of 0.6 to 220 *** different methodologies are employed to determine both n and ho:(1)optimizing linearity in a plot of Q1/n *** stage(hl)using UsGs field measurements at each site;(2)optimizing linearity in a plot of Q1/n *** using UsGs rating tables at each site;(3)a mathematical inverse method applied to the same UsGs rating tables;(4)use of li DAR data on channel geometry to determine the power dependences of channel area A and hydraulic radius H on h*,combined with the Manning and rational equations to predict *** these methods,only methods 2 and 3 compare favorably,and these values compare poorly with Method 1 based on field data,and with method 4 based on theoretical and empirical *** Method 4 is predictive,it provides a useful alternative to methods 1–3 that are based on UsGs field measurements,which are heavily weighted toward low *** conclude that the apparent values of n in the UsGs rating tables are systematically too low for small streams.

关键词： stream gauging li DAR topography urban flooding discharge hydrology

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Recent Progress on Flexible Room-Temperature Gas sensors Based on Metal Oxide semiconductor

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Nano-Micro letters 2022年第12期14卷 310-351页

作者： lang-Xi Ou Meng-Yang liu li-Yuan Zhu david wei Zhang Hong-liang lu state Key laboratory of AsIC and system Shanghai Institute of Intelligent Electronics&SystemsSchool of MicroelectronicsFudan UniversityShanghai 200433People’s Republic of China Yiwu Research Institute of Fudan University Chengbei RoadYiwu City 322000ZhejiangPeople’s Republic of China

With the rapid development of the Internet of Things,there is a great demand for portable gas *** oxide semiconductors(MOs)are one of the most traditional and well-studied gas sensing materials and have been widely used to prepare various commercial gas ***,it is limited by high operating *** current research works are directed towards fabricating high-performance flexible room-temperature(FRT)gas sensors,which are effective in simplifying the structure of MOs-based sensors,reducing power consumption,and expanding the application of portable *** article presents the recent research progress of MOs-based FRT gas sensors in terms of sensing mechanism,performance,flexibility characteristics,and *** review comprehensively summarizes and discusses five types of MOs-based FRT gas sensors,including pristine MOs,noble metal nanoparticles modified MOs,organic polymers modified MOs,carbon-based materials(carbon nanotubes and graphene derivatives)modified MOs,and two-dimensional transition metal dichalcogenides materials modified *** effect of light-illuminated to improve gas sensing performance is further ***,the applications and future perspectives of FRT gas sensors are also discussed.

关键词： Metal oxide semiconductor Flexible gas sensor Room temperature Nanomaterials

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Origins of the long-range exciton diffusion in perovskite nanocrystal films: photon recycling vs exciton hopping

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light(science & Applications) 2021年第1期10卷 41-49页

作者： david Giovanni Marcello Righetto Qiannan Zhang Jia wei Melvin lim sankaran Ramesh Tze Chien sum Division of Physics and Applied Physics School of Physical and Mathematical SciencesNanyang Technological University(NTU)21 Nanyang LinkSingapore 637371Singapore Energy Research Institute@NTU(ERI@N) Interdisciplinary Graduate SchoolNanyang Technological University50 Nanyang AvenueS2-B3a-01Singapore 639798Singapore

The outstanding optoelectronic performance of lead halide perovskites lies in their exceptional carrier diffusion *** the perovskite material dimensionality is reduced to exploit the quantum confinement effects,the disruption to the perovskite lattice,often with insulating organic ligands,raises new questions on the charge diffusion ***,we report direct imaging of>1μm exciton diffusion lengths in CH3NH3PbBr3 perovskite nanocrystal(PNC)***,the resulting exciton mobilities in these PNC films can reach 10±2cm^(2)V^(-1) s^(-1),,which is counterintuitively several times higher than the carrier mobility in 3D perovskite *** show that this ultralong exciton diffusion originates from both efficient inter-NC exciton hopping(via Forster energy transfer)and the photon recycling process with a smaller yet significant ***,our study not only sheds new light on the highly debated origins of the excellent exciton diffusion in PNC films but also highlights the potential of PNCs for optoelearonic applications.

关键词： properties. perovskite diffusion

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New Generations: sequencing Machines and Their Computational Challenges

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Journal of Computer science & Technology 2010年第1期25卷 3-9页

作者： david C. schwartz Michael s. Waterman laboratory for Molecular and Computational Genomics Departme4nt of Chemistry and Laboratory of Genetics University of Wisconsin-Madison Department of Biological sciences University of Southern California Department of Automation Tsinghua University

New generation sequencing systems are changing how molecular biology is practiced. The widely promoted $1000 genome will be a reality with attendant changes for healthcare, including personalized medicine. More broadly the genomes of many new organisms with large samplings from populations will be commonplace. What is less appreciated is the explosive demands on computation, both for CPU cycles and storage as well as the need for new computational methods. In this article we will survey some of these developments and demands.

关键词： genome sequencing new generation sequencing read mapping optical mapping sequence assembly Eulerian graphs

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Impact of great gerbils(Rhombomys opimus) on desert plant communities

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Journal of Arid land 2015年第6期7卷 852-859页

作者： XU Wenxuan lIU wei YANG weikang WANG Muyang XU Feng david BlANK Key laboratory of Biogeography and Bioresources in Arid lands Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences College of life science and Technology Southwest University for Nationalities

Great gerbil（Rhombomys opimus） colonies, with bare soil and herbaceous plants, are conspicuous to the background environment throughout their range area. In order to quantify the engineer role of great gerbils, we investigated the plant communities of 20 active colonies in the Junggar Basin, Xinjiang, China. In areas without disturbance, desert plant communities were dominated by the shrubs with low level species richness. In burrow areas and surrounding intermediate areas, which were disturbed by great gerbils, the shrubs were suppressed with the decrease of vegetation cover and aboveground biomass. As a result, ＂niche gaps＂ were created in disturbed areas and worked as a refuge for herbaceous annuals and perennials. so the existence of great gerbils increased the overall species richness of the desert. Furthermore, herbaceous annuals and perennials are the major food source for great gerbils in spring, indicating that great gerbils have a mutually beneficial relationship with herbaceous plants.

关键词： Rhombomys opimus ecosystem engineer species richness mutually beneficial relationship

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sound Modulation in singing Katydids Using Ionic Polymer-Metal Composites （IPMCs）

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Journal of Bionic Engineering 2013年第4期10卷 464-468页

作者： Yan Zhou Cheng-wei Chiu Carlos J. sanchez Jorge M. Gonzalez Benjamin Epstein david Rhodes s. Bradleigh Vinson Hong liang Materials Science and Engineering Texas A&M University College Station TX 77843 USA Department of Mechanical Engineering Texas' A&M University College Station TX 77843 USA Department of Entomology Texas A&M University College Station TX77843 USA Department of Plant science California State University Fresno CA 93740 USA OpCoast llC Brick NJ08723 USA

Many insect families have evolved to produce and detect complex singing patterns for the purposes of mating, display of dominance, predator escape, and other needs. While the mechanisms of sound production by insects have been thoroughly studied, man-machine exploitation of such mechanisms has remained unreported. We therefore describe a method to modulate the frequency spectrum in the chirp call of a singing insect, Gampsocleis gratiosa （Orthoptera： Tettigoniidae）, a large katydid indigenous to China and commonly known as Guo Guo or Chinese Bush Cricket. The chirp modulation was achieved through the contact of a ribbon of lonic Polymer-Metal Composite （IPMC） against wing of the insect. The IPMC effectively served as an actuator when a small DC voltage was applied to the ribbon＇s faces. By applying a sequential on/off voltage waveform to the IPMC ribbon, the katydid＇s chirp was modulated in a corresponding manner. This configuration can be used as part of a broader application of using singing insects to harness their acoustic power to produce and propagate machine-induced messages into the acoustic environment.

关键词： chirp modulation katydid IPMC

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Failure mechanism and simulation for long run-out of the catastrophic rock landslide in the shanyang Vanadium Mine,China

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Journal of Mountain science 2024年第9期21卷 2905-2917页

作者： lIU Yinpeng Mumtaz HAIDER david-darnor lAWRENCE lI Tonglu sHEN wei lI Ping College of Geological Engineering and Geomatics Chang’an UniversityXi’an 710054China Observation and Research station of Water Cycle and Geological Environment for the Chinese loess Plateau Ministry of EducationZhengning 745399China

On 12th August 2015,a massive rapid long run-out rock landslide occurred in the shanyang Vanadium Mine in shaanxi Province,China,which claimed the lives of 65 *** heavy rainfalls,earthquakes,and mining blasts were recorded before the ***,the failure mechanism and the cause of the long run-out movement are always in *** this paper,we conducted a detailed field investigation,laboratory tests,block theory analysis,and numerical simulation to investigate the failure and long run-out mechanisms of the *** field investigation results show that the source material of the rock landslide is a huge dolomite wedge block bedding on siliceous shale *** compression tests indicate that the uniaxial compression strength of the intact dolomite is 130-140MPa and the dolomite shows a brittle failure *** to the progressive downward erosion of the gully,the dolomite rock bridge at the slope toe became *** the compression stress in the dolomite bridge increased to surpass its strength,the brittle failure of the bridge *** huge potential energy was released following the disintegration of the landslide,which led to the high acceleration of this rock *** 3D discrete element simulation results suggest that the low intergranular friction contributes to the long run-out movement of this rock landslide.

关键词： Rock landslide Gully erosion long run-out Wedge block Discrete element method

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多用户场景支持多关键词模糊搜索的可搜索加密方案

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中国科学技术大学学报 2021年第7期51卷 562-576页

作者：凌华泽薛开平 wei david s.l. 李瑞东中国科学技术大学网络空间安全学院安徽合肥230027 美国福特汉姆大学计算机与信息科学系美国纽约104583 日本金泽大学科学与工程学院石川金泽920-1192

随着云计算平台的普及与推广,越来越多的企业和个人选择将数据外包到云以降低本地的维护成本,因此用于解决加密数据上关键字搜索问题的可搜索加密技术(searchable encryption,sE)变得越来越重要.模糊搜索概念的引入主要是为了解决查询... 详细信息

随着云计算平台的普及与推广,越来越多的企业和个人选择将数据外包到云以降低本地的维护成本,因此用于解决加密数据上关键字搜索问题的可搜索加密技术(searchable encryption,sE)变得越来越重要.模糊搜索概念的引入主要是为了解决查询关键词出现错误的情况.然而,现有的支持模糊搜索的可搜索加密方案不仅在多用户场景中具有很高的计算和通信开销,而且不能在保证有效准确率的前提下解决各种关键词错误类型.为此提出了一种多用户场景下支持多关键字模糊搜索的可搜索加密方案.具体来说,我们引入轮排索引来支持多关键字通配符搜索,可以以更高的正确率支持更多类型的模糊关键词.此外,通过让云服务器对索引信息进行重加密,本方案支持多用户场景非密钥共享的模糊搜索,有效降低了用户的计算开销并提高了隐私保护水平.实验结果表明,与现有方案相比,该方案不仅具有较高的准确率,而且能够以可接受的计算开销支持多种拼写错误的关键字搜索.

关键词：加密云存储代理重加密隐私保护可搜索加密

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Artificial intelligence for early detection of pancreatic adenocarcinoma: The future is promising

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World Journal of Gastroenterology 2021年第13期27卷 1283-1295页

作者： Antonio Mendoza ladd david l Diehl Department of Internal Medicine Division of GastroenterologyTexas Tech University Health Sciences Center El PasoEl PasoTX 79905United States Department of Gastroenterology and Nutrition Geisinger Medical CenterDanvillePA 17822United States

Pancreatic ductal adenocarcinoma(PDAC) is a worldwide public health concern. Despite extensive research efforts toward improving diagnosis and treatment, the 5-year survival rate at best is approximately 15%. This dismal figure can be attributed to a variety of factors including lack of adequate screening methods, late symptom onset, and treatment resistance. Pancreatic ductal adenocarcinoma remains a grim diagnosis with a high mortality rate and a significant psychological burden for patients and their families. In recent years artificial intelligence(AI) has permeated the medical field at an accelerated pace, bringing potential new tools that carry the promise of improving diagnosis and treatment of a variety of diseases. In this review we will summarize the landscape of AI in diagnosis and treatment of PDAC.

关键词： Pancreatic adenocarcinoma Artificial intelligence Neural network Future perspectives Early diagnosis Improved performance

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