scholarly journals The Evolution of the Goddard Profiling Algorithm to a Fully Parametric Scheme

2015 ◽  
Vol 32 (12) ◽  
pp. 2265-2280 ◽  
Author(s):  
Christian D. Kummerow ◽  
David L. Randel ◽  
Mark Kulie ◽  
Nai-Yu Wang ◽  
Ralph Ferraro ◽  
...  
Keyword(s):  
High Frequency ◽  
A Priori ◽  
Time Of Day ◽  
Parametric Approach ◽  
Ancillary Data ◽  
Microwave Sensor ◽  
Precipitation Estimates ◽  
Combined Algorithm ◽  
Ku Band ◽  
The Ideal

AbstractThe Goddard profiling algorithm has evolved from a pseudoparametric algorithm used in the current TRMM operational product (GPROF 2010) to a fully parametric approach used operationally in the GPM era (GPROF 2014). The fully parametric approach uses a Bayesian inversion for all surface types. The algorithm thus abandons rainfall screening procedures and instead uses the full brightness temperature vector to obtain the most likely precipitation state. This paper offers a complete description of the GPROF 2010 and GPROF 2014 algorithms and assesses the sensitivity of the algorithm to assumptions related to channel uncertainty as well as ancillary data. Uncertainties in precipitation are generally less than 1%–2% for realistic assumptions in channel uncertainties. Consistency among different radiometers is extremely good over oceans. Consistency over land is also good if the diurnal cycle is accounted for by sampling GMI product only at the time of day that different sensors operate. While accounting for only a modest amount of the total precipitation, snow-covered surfaces exhibit differences of up to 25% between sensors traceable to the availability of high-frequency (166 and 183 GHz) channels. In general, comparisons against early versions of GPM’s Ku-band radar precipitation estimates are fairly consistent but absolute differences will be more carefully evaluated once GPROF 2014 is upgraded to use the full GPM-combined radar–radiometer product for its a priori database. The combined algorithm represents a physically constructed database that is consistent with both the GPM radars and the GMI observations, and thus it is the ideal basis for a Bayesian approach that can be extended to an arbitrary passive microwave sensor.

The automatic identification of lexical variation between language varieties

2010 ◽  
Vol 16 (4) ◽  
pp. 469-491 ◽  
Author(s):  
YVES PEIRSMAN ◽  
DIRK GEERAERTS ◽  
DIRK SPEELMAN
Keyword(s):  
High Frequency ◽  
Automatic Identification ◽  
Distributional Semantics ◽  
Terminology Extraction ◽  
Lexical Variation ◽  
Language Varieties ◽  
Automatic Retrieval ◽  
Research Questions ◽  
Ideal Framework ◽  
The Ideal

AbstractLanguages are not uniform. Speakers of different language varieties use certain words differently – more or less frequently, or with different meanings. We argue that distributional semantics is the ideal framework for the investigation of such lexical variation. We address two research questions and present our analysis of the lexical variation between Belgian Dutch and Netherlandic Dutch. The first question involves a classic application of distributional models: the automatic retrieval of synonyms. We use corpora of two different language varieties to identify the Netherlandic Dutch synonyms for a set of typically Belgian words. Second, we address the problem of automatically identifying words that are typical of a given lect, either because of their high frequency or because of their divergent meaning. Overall, we show that distributional models are able to identify more lectal markers than traditional keyword methods. Distributional models also have a bias towards a different type of variation. In summary, our results demonstrate how distributional semantics can help research in variational linguistics, with possible future applications in lexicography or terminology extraction.

scholarly journals Design of a Compact CPW-Fed Monopole Antenna With Asymmetrical Hexagonal Slot Loaded Ground Structure for C/X/Ku Band Applications

2020 ◽  
Vol 16 (1) ◽  
pp. 15-22
Author(s):  
Ajay Kumar Dwivedi ◽  
Brijesh Mishra ◽  
Vivek Singh ◽  
Pramod Narayan Tripathi ◽  
Ashutosh Kumar Singh
Keyword(s):  
High Frequency ◽  
Ground Plane ◽  
Directional Pattern ◽  
Ultra Wideband ◽  
Impedance Bandwidth ◽  
Ground Structure ◽  
High Frequency Structure Simulator ◽  
Performance Matrix ◽  
Novel Design ◽  
Ku Band

AbstractA novel design of ultra-wideband CPW-fed compact monopole patch antenna is presented in the article. The size of the antenna is 22 × 18 × 1.6 mm and it operates well over an ultra-wideband frequency range 4.86–13.66 GHz (simulated) and 4.93–13.54 GHz (measured) covering C, X and partial Ku band applications. The proposed design consists of a defected ground plane and U-shape radiating patch along with two square shape parasitic patches in order to achieve the ultra-wideband (UWB) operations. The performance matrix is validated through measured results that indicate the wide impedance bandwidth (93.2 %) with maximum gain of 4 dBi with nearly 95 % of maximum radiation efficiency; moreover, the 3D gain pattern manifests approximately omni-directional pattern of the proposed design. The prototype has been modelled using HFSS (High Frequency Structure Simulator-18) by ANSYS, fabricated and tested using vector network analyser E5071C.

scholarly journals Enhancement of Bandwidth using Inset-Fed Patch Antenna for High Frequency Applications

2019 ◽  
Vol 9 (1) ◽  
pp. 1528-1531
Keyword(s):  
Patch Antenna ◽  
High Frequency ◽  
Low Cost ◽  
High Frequencies ◽  
Simulation Results ◽  
Ku Band

Today in communication field, many antennas have been evolved for various applications. The most popularly used antennas are micro-strip antennas. These antennas can be easily fabricated at reasonably low cost. Hence, these antennas are gaining lot of importance in recent times. Many techniques have been in use for micro strip antennas to improve the performance of the antenna parameters. The design of these antennas is slowly moving towards high frequencies, where there is lot of advantage with bandwidth. In this paper a normal and E shaped inset micro-strip antenna in Ku-Band is simulated and the results are presented. It is noted that CST-MS 2015 tool has been used to get the simulation results.

Commercial microwave links instead of rain gauges: fiction or reality?

2014 ◽  
Vol 71 (1) ◽  
pp. 31-37 ◽  
Author(s):  
Martin Fencl ◽  
Jörg Rieckermann ◽  
Petr Sýkora ◽  
David Stránský ◽  
Vojtěch Bareš
Keyword(s):  
Rainfall Variability ◽  
A Priori ◽  
Rain Gauges ◽  
Precipitation Estimates ◽  
Spatio Temporal ◽  
Areal Rainfall ◽  
Quantitative Precipitation Estimates ◽  
Commercial Microwave Links ◽  
Unique Dataset

Commercial microwave links (MWLs) were suggested about a decade ago as a new source for quantitative precipitation estimates (QPEs). Meanwhile, the theory is well understood and rainfall monitoring with MWLs is on its way to being a mature technology, with several well-documented case studies, which investigate QPEs from multiple MWLs on the mesoscale. However, the potential of MWLs to observe microscale rainfall variability, which is important for urban hydrology, has not been investigated yet. In this paper, we assess the potential of MWLs to capture the spatio-temporal rainfall dynamics over small catchments of a few square kilometres. Specifically, we investigate the influence of different MWL topologies on areal rainfall estimation, which is important for experimental design or to a priori check the feasibility of using MWLs. In a dedicated case study in Prague, Czech Republic, we collected a unique dataset of 14 MWL signals with a temporal resolution of a few seconds and compared the QPEs from the MWLs to reference rainfall from multiple rain gauges. Our results show that, although QPEs from most MWLs are probably positively biased, they capture spatio-temporal rainfall variability on the microscale very well. Thus, they have great potential to improve runoff predictions. This is especially beneficial for heavy rainfall, which is usually decisive for urban drainage design.

scholarly journals Sundown syndrome in patients with Alzheimer’s disease dementia

2019 ◽  
Vol 13 (4) ◽  
pp. 469-474 ◽  
Author(s):  
Cristiani Sartorio Menegardo ◽  
Fernanda Alencar Friggi ◽  
Julia Baldon Scardini ◽  
Tais Souza Rossi ◽  
Thais dos Santos Vieira ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
High Frequency ◽  
Neuropsychiatric Symptoms ◽  
Time Of Day ◽  
Neuropsychiatric Inventory ◽  
Cross Sectional ◽  
Symptom Intensity ◽  
The Family ◽  
Alzheimer’S Disease Dementia

ABSTRACT The sundown syndrome is a complex neurobehavioral disorder in patients with dementia associated with high financial cost and significant caregiver burden. It is a multifactorial phenomenon with unclear pathophysiology, characterized by the presence of neuropsychiatric symptoms in the evening period. Objective: To analyze the main neuropsychiatric symptoms, their correlation with one another, with comorbidities, and with time of day of greatest symptom intensity in patients with Alzheimer’s disease dementia. Methods: This is a cross-sectional, observational and explanatory study in which caregivers/relatives of elderly patients with dementia were interviewed using a structured tool called the Neuropsychiatric Inventory (NPI). Results: The sample studied was composed of 38 patients, 60.5% female and 39.5% male, with mean age of 81±6 (67-94) years. A high frequency of neuropsychiatric symptoms in the evening period was observed, predominantly irritability (55.3%), nocturnal behavior (47.4%), and aggressiveness (42.1%). Only 36.8% of the family caregivers used non-pharmacological strategies. Conclusion: The frequency of neuropsychiatric symptoms was exacerbated in the evening among patients with Alzheimer’s disease, especially for those behavioral symptoms that had a positive correlation with one another.

Automatic Vehicle Access System using Ultra-High Frequency RFID

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Priscilla Swee Pei Poh ◽  
◽  
Rafidah Ngadengon ◽  
Keyword(s):  
High Frequency ◽  
Cloud Storage ◽  
Entry And Exit ◽  
Site Location ◽  
Ultra High Frequency ◽  
Access System ◽  
Future Improvement ◽  
User Data ◽  
Secure Monitoring ◽  
The Ideal

Securing and monitoring the territory have become a big challenge for everyone as the number of vehicle users have increased. The premise area must be secure with enforced entrances and exits. It should have an automated and efficient security and monitoring system. For this purpose, an automated vehicle access system with accurate and secure monitoring of vehicle entry and exit was developed with Graphical User Interface (GUI) and vehicle’s user database along with the prototype of Ultra-High Frequency RFID. The suitable configuration for the hardware prototype has also been evaluated to maximize the system’s capabilities. This system operates on frequencies from 400MHz to 950MHz and is performed at distances of 7 meters. The passive tag was attached to the various condition and sizes of the car. The result shows showed that the system was optimally performed with the speed of the vehicle up to 50 km/h, 7 m of reading range and a maximum 20% tinted windshield. The ideal angle for the reader is around 60ᵒ to 70ᵒ with 2 meters of mounting pole. For future improvement, it is suggested that the registered vehicle user data was linked with the official premise’s database and the data is saved in an off-site location (cloud storage). The GUI is also able to support more than 1 reader at a time depending on demand.

Understanding performance of GPROF precipitation retrievals over the Netherlands in relation to precipitation characteristics as derived from ground-based dual-polarization radars

2021 ◽  
Author(s):  
Linda Bogerd ◽  
Hidde Leijnse ◽  
Aart Overeem ◽  
Remko Uijlenhoet
Keyword(s):  
The Netherlands ◽  
Background Radiation ◽  
A Priori ◽  
Dual Frequency ◽  
Dual Polarization ◽  
Ground Clutter ◽  
Precipitation Measurement ◽  
Precipitation Estimates ◽  
Global Precipitation ◽  
Precipitation Events

<p>The Global Precipitation Measurement mission (GPM) is one of the recent efforts to provide satellite-based global precipitation estimates. The GPM Profiling Algorithm (GPROF) converts microwave radiation measured by passive microwave (PMW) sensors onboard constellation satellites into precipitation. Over land, precipitation estimates are obtained from high frequency PMW-channels that measure the radiance scattered by ice particles in rain clouds. However, due to the limited scattering related to shallow and light precipitation, it is challenging to distinguish these signals from background radiation that is naturally emitted from the Earth’s surface.</p><p>Increased understanding of the physical processes during precipitation events can be used to improve PMW-based precipitation retrievals. This study couples overpasses of GPM radiometers over the Netherlands to two dual-polarization radars from the Royal Netherlands Meteorological Institute (KNMI). The Netherlands is an ideal setting for this study due to the availability of high-quality ground-based measurements, the frequent occurrence of shallow events, the absence of ground-clutter related to mountains, and the varying background emission related to its coastal location.</p><p>The coupling of overpasses with ground-based precipitation radars provides the opportunity to relate GPROFs performance to physical characteristics of precipitation events, such as the vertical reflectivity profile and dual-polarization information on the melting layer. Furthermore, simultaneous radiometer estimates and space-based reflectivity profiles from the dual-frequency precipitation radar (DPR) onboard the GPM core satellite are coupled to the ground-based reflectivity profiles for selected case studies. Because the a-priori database implemented in the GPROF algorithm is based on observations from the DPR, the comparison of the reflectivity profiles further unravels discrepancies between GPROF and ground-based estimates.</p>

scholarly journals Tropical Cyclone Rain Retrievals from FY-3B MWRI Brightness Temperatures Using the Goddard Profiling Algorithm (GPROF)

2019 ◽  
Vol 36 (5) ◽  
pp. 849-864 ◽  
Author(s):  
Ruanyu Zhang ◽  
Christian D. Kummerow ◽  
David L. Randel ◽  
Paula J. Brown ◽  
Wesley Berg ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
A Priori ◽  
Dual Frequency ◽  
Ancillary Data ◽  
Light Rain ◽  
Brightness Temperatures ◽  
The Mean ◽  
Microwave Imager ◽  
Rain Rates ◽  
Global Precipitation

AbstractThis study focuses on the tropical cyclone rainfall retrieval using FY-3B Microwave Radiation Imager (MWRI) brightness temperatures (Tbs). The GPROF, a fully parametric approach based on the Bayesian scheme, is adapted for use by the MWRI sensor. The MWRI GPROF algorithm is an ocean-only scheme used to estimate rain rates and hydrometeor vertical profiles. An a priori database is constructed from MWRI simulated Tbs, the GPM Microwave Imager (GMI) and Dual-Frequency Precipitation Radar (DPR) combined data, and ancillary data resulting in about 100 000 rainfall profiles. The performance of MWRI retrievals is consistent with DPR observations, even though MWRI retrievals slightly overestimate low rain rates and underestimate high rain rates. The total bias of MWRI retrievals is less than 13% of the mean rain rate of DPR precipitation. Statistical comparisons over GMI GPROF, GMI Hurricane GPROF (HGPROF), and MWRI GPROF retrievals show MWRI GPROF retrievals are consistent in terms of spatial distribution and rain estimates for TCs compared with the other two estimates. In terms of the global precipitation, the mean rain rates at different distances from best track locations for five TC categories are used to identify substantial differences between mean MWRI and GMI GPROF retrievals. After correcting the biases between MWRI and GMI retrievals, the performance of MWRI retrievals shows slight overestimate for light rain rates while underestimating rain rates near the eyewall for category 4 and 5 only.

scholarly journals Correlation based snapshot models of the archeomagnetic field

2020 ◽  
Vol 223 (1) ◽  
pp. 648-665
Author(s):  
S Mauerberger ◽  
M Schanner ◽  
M Korte ◽  
M Holschneider
Keyword(s):  
Model Uncertainty ◽  
Geomagnetic Field ◽  
A Priori ◽  
Field Vector ◽  
Parametric Approach ◽  
Full Field ◽  
The Past ◽  
Uncertainty Estimates ◽  
Improved Model ◽  
Field Estimate

SUMMARY For the time stationary global geomagnetic field, a new modelling concept is presented. A Bayesian non-parametric approach provides realistic location dependent uncertainty estimates. Modelling related variabilities are dealt with systematically by making little subjective a priori assumptions. Rather than parametrizing the model by Gauss coefficients, a functional analytic approach is applied. The geomagnetic potential is assumed a Gaussian process to describe a distribution over functions. A priori correlations are given by an explicit kernel function with non-informative dipole contribution. A refined modelling strategy is proposed that accommodates non-linearities of archeomagnetic observables: First, a rough field estimate is obtained considering only sites that provide full field vector records. Subsequently, this estimate supports the linearization that incorporates the remaining incomplete records. The comparison of results for the archeomagnetic field over the past 1000 yr is in general agreement with previous models while improved model uncertainty estimates are provided.

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