Efficient Data Retrieval Algorithm for Multi-Request in Multi-Antenna Wireless Networks

2016 ◽  
Author(s):  
Ping He ◽  
Zheng Huo
Keyword(s):  
Wireless Networks ◽  
Data Retrieval ◽  
Retrieval Algorithm ◽  
Efficient Data

Tangent height registration method for the Version 14 data retrieval algorithm of the solar occultation sensor ILAS-II

2007 ◽  
Vol 46 (29) ◽  
pp. 7196 ◽  
Author(s):  
Tomoaki Tanaka ◽  
Hideaki Nakajima ◽  
Takafumi Sugita ◽  
Mitsumu K. Ejiri ◽  
Hitoshi Irie ◽  
...  
Keyword(s):  
Data Retrieval ◽  
Retrieval Algorithm ◽  
Registration Method ◽  
Solar Occultation

Validation of TROPOMI nadir ozone profile retrievals: Methodology and first results

2021 ◽  
Author(s):  
Arno Keppens ◽  
Jean-Christopher Lambert ◽  
Daan Hubert ◽  
Steven Compernolle ◽  
Tijl Verhoelst ◽  
...  
Keyword(s):  
Near Infrared ◽  
Stratospheric Ozone ◽  
Estimation Method ◽  
Optimal Estimation ◽  
Data Retrieval ◽  
Atmospheric Composition ◽  
Retrieval Algorithm ◽  
Validation Data ◽  
Ozone Profile ◽  
Early Afternoon

<p>Part of the space segment of EU’s Copernicus Earth Observation programme, the Sentinel-5 Precursor (S5P) mission is dedicated to global and European atmospheric composition measurements of air quality, climate and the stratospheric ozone layer. On board of the S5P early afternoon polar satellite, the imaging spectrometer TROPOMI (TROPOspheric Monitoring Instrument) performs nadir measurements of the Earth radiance within the UV-visible and near-infrared spectral ranges, from which atmospheric ozone profile data are retrieved. Developed at the Royal Netherlands Meteorological Institute (KNMI) and based on the optimal estimation method, TROPOMI’s operational ozone profile retrieval algorithm has recently been upgraded. With respect to early retrieval attempts, accuracy is expected to have improved significantly, also thanks to recent updates of the TROPOMI Level-1b data product. This work reports on the initial validation of the improved TROPOMI height-resolved ozone data in the troposphere and stratosphere, as collected both from the operational S5P Mission Performance Centre/Validation Data Analysis Facility (MPC/VDAF) and from the S5PVT scientific project CHEOPS-5p. Based on the same validation best practices as developed for and applied to heritage sensors like GOME-2, OMI and IASI (Keppens et al., 2015, 2018), the validation methodology relies on the analysis of data retrieval diagnostics – like the averaging kernels’ information content – and on comparisons of TROPOMI data with reference ozone profile measurements. The latter are acquired by ozonesonde, stratospheric lidar, and tropospheric lidar stations performing network operation in the context of WMO's Global Atmosphere Watch and its contributing networks NDACC and SHADOZ. The dependence of TROPOMI’s ozone profile uncertainty on several influence quantities like cloud fraction and measurement parameters like sun and scan angles is examined and discussed. This work concludes with a set of quality indicators, enabling users to verify the fitness-for-purpose of the S5P data.</p>

Querying Multidimensional Data

2003 ◽  
pp. 252-281
Author(s):  
Leonardo Tininini
Keyword(s):  
Algebraic Approach ◽  
Evaluation Process ◽  
Data Retrieval ◽  
Data Cube ◽  
Multidimensional Data ◽  
Integration Policy ◽  
Multidimensional Database ◽  
Efficient Data ◽  
Speed Up ◽  
Logical Data

A powerful and easy-to-use querying environment is certainly one of the most important components in a multidimensional database, and its effectiveness is influenced by many other aspects, both logical (data model, integration, policy of view materialization, etc.) and physical (multidimensional or relational storage, indexes, etc.). As is evident, multidimensional querying is often based on the metaphor of the data cube and on the concepts of facts, measures, and dimensions. In contrast to conventional transactional environments, multidimensional querying is often an exploratory process, performed by navigating along the dimensions and measures, increasing/decreasing the level of detail and focusing on specific subparts of the cube that appear to be “promising” for the required information. In this chapter we focus on the main languages proposed in the literature to express multidimensional queries, particularly those based on: (i) an algebraic approach, (ii) a declarative paradigm (calculus), and (iii) visual constructs and syntax. We analyze the problem of evaluation, i.e., the issues related to the efficient data retrieval and calculation, possibly (often necessarily) using some pre-computed data, a problem known in the literature as the problem of rewriting a query using views. We also illustrate the use of particular index structures to speed up the query evaluation process.

scholarly journals A Conceptual Model for Art Criticism

2019 ◽  
pp. 138-157
Author(s):  
Maria Giovanna Mancini ◽  
Luigi Sauro
Keyword(s):  
Detailed Analysis ◽  
Conceptual Model ◽  
Art Criticism ◽  
Data Retrieval ◽  
Conceptual Modelling ◽  
Related Data ◽  
Efficient Data ◽  
Cidoc Crm

In this work, we present a detailed analysis of the different acceptations and practices of art criticism. This investigation underpins a novel conceptual modelling that extends Cidoc CRM and has been specifically designed to semantically annotate art criticism-related data and documents in order to enhance in this context interoperability and more efficient data retrieval.

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