检索结果-内蒙古大学图书馆

6th International Symposium on Computer Science and Intelligent Control (ISCSIC)

作者： Ji Tenghao HongKong Polytech Univ Elect Engn Hong Kong Peoples R China

ISBN: (纸本)9781665454889

Frequently asked questions (FAQ) is a typical limited domain-oriented retrieval question answering system, and semantic similarity matching is the key technology of FAQ question answering. Aiming at the FAQ problems of insufficient deep semantic representation and extraction and synonyms and polysemy, this paper proposes a cascade matching model combining coarse-grained recall and finegrained sorting. Firstly, an improved Okapi BM25 algorithm based on inverse word frequency is proposed. This paper proposes a new solution to FAQ answer based on the traditional text matching and retrieval pipeline, and gives a new semantic similarity matching model. Additionally, we further analyze the shortcomings of semantic matching and the advantages of data-driven semantic similarity matching model. Finally, the proposed hybrid matching model is evaluated. Experimental results show that the proposed method not only ensures the retrieval speed of question and answer, but improves its performance

关键词： FAQ Question Answering Semantic Similarity Text matching retrieval algorithm

来源：评论

学校读者我要写书评

暂无评论

MULTI-FREQUENCY SIGNALS OF OPPORTUNITY SOIL MOISTURE retrievalS FOR AGRICULTURAL APPLICATIONS

MULTI-FREQUENCY SIGNALS OF OPPORTUNITY SOIL MOISTURE RETRIEV...

引用

IEEE International Geoscience and Remote Sensing Symposium (IGARSS)

作者： Kim, Seho Smith, Eric P. Nold, Benjamin R. Choudhari, Archana S. Garrison, James L. Purdue Univ Sch Aeronaut & Astronaut W Lafayette IN 47907 USA

ISBN: (数字)9781665427920

ISBN: (纸本)9781665427920

Root-zone soil moisture (RZSM) is one of the least measured hydrological variables despite its critical role in understanding the global carbon cycle and forecasting agricultural drought and food production. Signals of opportunity (SoOp) has great potential to overcome the limitation of conventional microwave methods to utilize lower frequencies in space-borne remote sensing. Multi-frequency SoOp reflectometry (SoOp-R) offers a promising solution to measure RZSM by solving the inverse problem for obtaining multi-layer soil moisture profiles. This paper summarizes ongoing work to develop and validate multi-frequency SoOp-R to retrieve RZSM, including forward and inverse methods, sensitivity analysis for the optimal frequency combination, and tower-based field experiments.

关键词： Root-zone soil moisture signals of opportunity multi-frequency observation retrieval algorithm field experiment

来源：评论

学校读者我要写书评

暂无评论

Potential of AOD retrieval Using Atmospheric Emitted Radiance Interferometer (AERI)

引用

REMOTE SENSING 2022年第2期14卷

作者： Seo, Jongjin Choi, Haklim Oh, Youngsuk Univ Wisconsin Dept Atmospher & Ocean Sci Madison WI 53706 USA Univ Wisconsin Space Sci & Engn Ctr Madison WI 53706 USA Kyungpook Natl Univ Kyungpook Inst Oceanog Daegu 41566 South Korea Natl Inst Meteorol Sci Innovat Meteorol Res Dept Seogwipo Si 63568 South Korea

Aerosols in the atmosphere play an essential role in the radiative transfer process due to their scattering, absorption, and emission. Moreover, they interrupt the retrieval of atmospheric properties from ground-based and satellite remote sensing. Thus, accurate aerosol information needs to be obtained. Herein, we developed an optimal-estimation-based aerosol optical depth (AOD) retrieval algorithm using the hyperspectral infrared downwelling emitted radiance of the Atmospheric Emitted Radiance Interferometer (AERI). The proposed algorithm is based on the phenomena that the thermal infrared radiance measured by a ground-based remote sensor is sensitive to the thermodynamic profile and degree of the turbid aerosol in the atmosphere. To assess the performance of algorithm, AERI observations, measured throughout the day on 21 October 2010 at Anmyeon, South Korea, were used. The derived thermodynamic profiles and AODs were compared with those of the European center for a reanalysis of medium-range weather forecasts version 5 and global atmosphere watch precision-filter radiometer (GAW-PFR), respectively. The radiances simulated with aerosol information were more suitable for the AERI-observed radiance than those without aerosol (i.e., clear sky). The temporal variation trend of the retrieved AOD matched that of GAW-PFR well, although small discrepancies were present at high aerosol concentrations. This provides a potential possibility for the retrieval of nighttime AOD.

关键词： retrieval algorithm AOD AERI hyper-spectral infrared optimal estimation method

来源：评论

学校读者我要写书评

暂无评论

A Method for Retrieving Land Surface Temperature From Ground-/UAV-Based Longwave Infrared Data

引用

IEEE GEOSCIENCE AND REMOTE SENSING LETTERS 2025年 22卷

作者： Li, Mingsong Zhou, Ji Ma, Jin Wang, Ziwei Univ Elect Sci & Technol China Sch Resources & Environm Chengdu 611731 Peoples R China

The longwave infrared (LWIR) sensors are widely used for measuring land surface radiation in ground and uncrewed aerial vehicle (UAV) remote sensing missions. Although the land surface temperature (LST) retrieval algorithms for thermal infrared (TIR) satellite sensors with narrow spectral response ranges have achieved good results, they are generally unsuitable for LWIR sensors. At present, the LST retrieval algorithm for LWIR data needs further investigation. In this study, an improved radiative transfer (IRT) algorithm based on the segmentation of spectral response function (SRF) is proposed for retrieving LST from LWIR data. The IRT algorithm is applied to three types of commonly used LWIR sensors. The simulation results show that the root-mean-squared error (RMSE) is lower than 0.1 K when the segmentation width is 0.2 mu m. The higher the height of the sensor, the more obvious the fluctuation of the accuracy increases with the segmentation width. Using the in situ data of the Heihe River basin (HRB) for validation, RMSEs are between 1.1 and 1.8 K, depending on different land cover types. The IRT algorithm can retrieve the relatively high-accuracy LSTs from LWIR data observed by a variety of LWIR sensors and promote the collaborative application of multisensor LSTs, which is of great significance in ecological environment research.

关键词： Sensors Land surface temperature Land surface Soil Temperature sensors Radiometers Autonomous aerial vehicles Urban areas Temperature measurement Sensor phenomena and characterization Ground and uncrewed aerial vehicle (UAV) observation land surface temperature (LST) longwave infrared (LWIR) data LWIR sensor retrieval algorithm

来源：评论

学校读者我要写书评

暂无评论

retrieval of the Statistical Characteristics of Wind Waves From the Width and Shift of the Doppler Spectrum of the Backscattered Microwave Signal at Low Incidence Angles

引用

IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 2020年第3期58卷 2225-2231页

作者： Panfilova, Maria Ryabkova, Maria Karaev, Vladimir Skiba, Ekaterina Russian Acad Sci Inst Appl Phys Lab Radiophys Methods World Ocean Res Nizhnii Novgorod 603950 Russia Russian Acad Sci Marine Hydrophys Inst Sevastopol 299021 Russia

The Doppler spectrum (DS) of the signal backscattered at the low incidence angles from the sea surface was measured by the Ka-band radar in an experiment on a marine oceanographic platform. The directional elevation spectrum of sea waves was measured simultaneously by a six-string wave gauge mounted on a platform. At low incidence angles the backscattering mechanism is quasi-specular, and DS of the backscattered signal is calculated in the Kirchhoff approximation with the antenna pattern being taken into account. In the case of pure wind sea, the parameters of the sea waves spectrum model (wind speed and fetch) were retrieved by 2-D optimization method from measured DS shift and width. Sea wave propagation direction was obtained from the azimuthal dependence of Doppler shift. Analytical dependence of DS shift and width on incidence angle calculated from the spectrum model is in a good agreement with the experiment for incidence angles from 0 degrees to 12 degrees. Close values of significant wave height, the average wave period, and the variance of orbital velocities were obtained from the retrieved model spectrum and from the spectrum directly measured by the string wave gauge, which also proves the correctness of DS model.

关键词： Microwave signal retrieval algorithm statistical parameters of sea waves width and shift of Doppler spectrum (DS)

来源：评论

学校读者我要写书评

暂无评论

Model Selection in Atmospheric Remote Sensing with Application to Aerosol retrieval from DSCOVR/EPIC. Part 2: Numerical Analysis

引用

REMOTE SENSING 2020年第21期12卷 1-17页

作者： Sasi, Sruthy Natraj, Vijay Molina Garcia, Victor Efremenko, Dmitry S. Loyola, Diego Doicu, Adrian German Aerosp Ctr DLR Remote Sensing Technol Inst D-82234 Oberpfaffenhofen Germany CALTECH Jet Prop Lab NASA JPL 4800 Oak Grove Dr Pasadena CA 91109 USA

An algorithm for retrieving aerosol parameters by taking into account the uncertainty in aerosol model selection is applied to the retrieval of aerosol optical thickness and aerosol layer height from synthetic measurements from the EPIC sensor onboard the Deep Space Climate Observatory. The synthetic measurements are generated using aerosol models derived from AERONET measurements at different sites, while other commonly used aerosol models, such as OPAC, GOCART, OMI, and MODIS databases are used in the retrieval. The numerical analysis is focused on the estimation of retrieval errors when the true aerosol model is unknown. We found that the best aerosol model is the one with a value of the asymmetry parameter and an angular variation of the phase function around the viewing direction that is close to the values corresponding to the reference aerosol model.

关键词： model selection retrieval algorithm DSCOVR/EPIC

来源：评论

学校读者我要写书评

暂无评论

Direct reconstruction of isolated XUV or soft x-ray attosecond pulses from high-harmonic generation streaking spectra

引用

NEW JOURNAL OF PHYSICS 2023年第8期25卷 083003-083003页

作者： Wang, Kan Fu, Yong Li, Baochang Tang, Xiangyu Wang, Bincheng Guan, Zhong Lin, C. D. Jin, Cheng Nanjing Univ Sci & Technol Dept Appl Phys Nanjing 210094 Jiangsu Peoples R China Kansas State Univ Dept Phys JR Macdonald Lab Manhattan KS 66506 USA Nanjing Univ Sci & Technol MIIT Key Lab Semicond Microstruct & Quantum Sensin Nanjing 210094 Jiangsu Peoples R China

Characterization of an isolated attosecond pulse (IAP) in the extreme ultraviolet (XUV) or soft x-ray (SXR) region is essential for its applications. Here we propose to retrieve an IAP in the time domain directly through the modulation of high-harmonic generation (HHG) spectra in the presence of a time-delayed intense few-cycle infrared or mid-infrared laser. The retrieval algorithm is derived based on the strong-field approximation and an extended quantitative rescattering model. We show that both isolated XUV pulses with a narrow spectral bandwidth and isolated SXR pulses with a broad bandwidth can be well characterized through the HHG streaking spectra. Such an all-optical method for characterizing the IAP differs from the commonly used approach based on the streaked photoelectron spectra that would require electron spectrometers. We check the robustness of the retrieval method by changing the dressing laser or by adjusting the steps of time delay. We also show that the XUV pulse can be accurately retrieved by treating the HHG streaking spectra calculated from solving the time-dependent Schrodinger equation for single atoms as the 'experimental' data.

关键词： isolated attosecond pulses high-harmonic generation streaking spectra infrared or mid-infrared laser extreme ultraviolet or soft x-ray retrieval algorithm

来源：评论

学校读者我要写书评

暂无评论

Global retrieval of phytoplankton functional types based on empirical orthogonal functions using CMEMS GlobColour merged products and further extension to OLCI data

引用

REMOTE SENSING OF ENVIRONMENT 2020年 240卷

作者： Xi, Hongyan Losa, Svetlana N. Mangin, Antoine Soppa, Mariana A. Garnesson, Philippe Demaria, Julien Liu, Yangyang D'Andon, Odile Hembise Fanton Bracher, Astrid Helmholtz Ctr Polar & Marine Res Alfred Wegener Inst Bremerhaven Germany Russian Acad Sci Shirshov Inst Oceanol Moscow Russia ACRI ST F-06904 Sophia Antipolis France Univ Bremen Fac Biol & Chem Bremen Germany Univ Bremen Inst Environm Phys Bremen Germany

This study presents an algorithm for globally retrieving chlorophyll a (Chl-a) concentrations of phytoplankton functional types (PFTs) from multi-sensor merged ocean color (OC) products or Sentinel-3A (S3) Ocean and Land Color Instrument (OLCI) data from the GlobColour archive in the frame of the Copernicus Marine Environmental Monitoring Service (CMEMS). The retrieved PFTs include diatoms, haptophytes, dinoflagellates, green algae and prokaryotic phytoplankton. A previously proposed method to retrieve various phytoplankton pigments, based on empirical orthogonal functions (EOF), is investigated and adapted to retrieve Chl-a concentrations of multiple PFTs using extensive global data sets of in situ pigment measurements and matchups with satellite OC products. The performance of the EOF-based approach is assessed and cross-validated statistically. The retrieved PFTs are compared with those derived from diagnostic pigment analysis (DPA) based on in situ pigment measurements. Results show that the approach predicts well Chl-a concentrations of most of the mentioned PFTs. The performance of the approach is, however, less accurate for prokaryotes, possibly due to their general low variability and small concentration range resulting in a weak signal which is extracted from the reflectance data and corresponding EOF modes. As a demonstration of the approach utilization, the EOF-based fitted models based on satellite reflectance products at nine bands are applied to the monthly GlobColour merged products. Climatological characteristics of the PFTs are also evaluated based on ten years of merged products (2002-2012) through inter-comparisons with other existing satellite derived products on phytoplankton composition including phytoplankton size class (PSC), SynSenPFT, OC-PFT and PHYSAT. Inter-comparisons indicate that most PFTs retrieved by our study agree well with previous corresponding PFT/PSC products, except that prokaryotes show higher Chl-a concentration in low latit

关键词： retrieval algorithm Chlorophyll a Phytoplankton functional types Empirical orthogonal functions Remote sensing reflectance HPLC pigments CMEMS GlobColour OLCI

来源：评论

学校读者我要写书评

暂无评论

Variation of Antarctic marginal ice zone extent (1989-2019)

引用

Advances in Polar Science 2021年第4期32卷 341-355页

作者： WANG Miaojiang LIU Tingting YANG Zijian WU Bing ZHU Xueming Changzhou Xinbei Natural Resources and Planning Technical Support Center Changzhou 213001China Chinese Antarctic Center of Surveying and Mapping Wuhan UniversityWuhan 430072China

The Antarctic marginal ice zone(MIZ)is the transition region between open water and consolidated pack ice,which is defined as an area with 15%-80%sea ice *** MIZ represents the outer circle of Antarctic sea ice and the biological activity circle of Antarctic organisms,which provides a direct indication of the extent of Antarctic sea *** this study,the joint total variation and nonnegative constrained least square algorithm are applied to retrieve the Antarctic MIZ extent based on passive microwave data sets from 1989 to *** spatial and temporal variations of the Antarctic MIZ extent and five regions are *** results show that the Antarctic MIZ extent follows a strong monthly variation pattern,decreasing from November to February and increasing from March to *** annual MIZ extent is largest in the Weddell Sea and smallest in the Western Pacific *** edge of the sea ice begins to form a closed ring in May,which eventually closes near the Antarctic *** ring width variation is large in summer,but generally stabilizes between 350 and 370 km in *** average latitude of the Antarctic MIZ is relatively stable in summer,but changes substantially in winter with a difference of approximately 3°.In October,the lowest mean latitude of the MIZ can reach 64.35°*** sea surface pressure,2-m temperature,and 10-m wind speed are negatively correlated with the MIZ extent variation,among which the second-order partial correlation coefficient of the sea surface pressure and MIZ extent is−0.8773 in the Western Pacific Ocean.

关键词： Antarctic marginal ice zone passive microwave data retrieval algorithm correlation analysis variation

来源：评论

学校读者我要写书评

暂无评论

A New Global Solar-induced Chlorophyll Fluorescence(SIF)Data Product from TanSat Measurements

引用

Advances in Atmospheric Sciences 2021年第3期38卷 341-345页

作者： Lu YAO Dongxu YANG Yi LIU Jing WANG Liangyun LIU Shanshan DU Zhaonan CAI Naimeng LU Daren LYU Maohua WANG Zengshan YIN Yuquan ZHENG Key Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201210China Key Laboratory of Digital Earth Science Institute of Remote Sensing and Digital EarthChinese Academy of SciencesBeijing 100094China National Satellite Meteorological Center China Meteorological AdministrationBeijing 100081China Changchun Institute of Optics Fine Mechanics and PhysicsChangchun 130033China Shanghai Engineering Center for Microsatellites Shanghai 201210China

The Chinese Carbon Dioxide Observation Satellite Mission(TanSat)is the third satellite for global CO2 monitoring and is capable of detecting weak solar-induced chlorophyll fluorescence(SIF)signals with its advanced technical *** on the Institute of Atmospheric Physics Carbon Dioxide retrieval algorithm for Satellite Remote Sensing(IAPCAS)platform,we successfully retrieved the TanSat global SIF product spanning the period of March 2017 to February 2018 with a physically based *** paper introduces the new TanSat SIF dataset and shows the global seasonal SIF maps.A brief comparison between the IAPCAS TanSat SIF product and the data-driven SVD(singular value decomposition)SIF product is also performed for follow-up algorithm *** comparative results show that there are regional biases between the two SIF datasets and the linear correlations between them are above 0.73 for all *** future SIF data product applications and requirements for SIF space observation are discussed.

关键词： TanSat solar-induced chlorophyll fluorescence retrieval algorithm remote sensing

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：