scholarly journals Airborne polarimetric Doppler weather radar: trade-offs between various engineering specifications

2018 ◽  
Vol 7 (1) ◽  
pp. 21-37 ◽  
Author(s):  
Jothiram Vivekanandan ◽  
Eric Loew
Keyword(s):  
Single Channel ◽  
Adaptive Beamforming ◽  
Optimal Number ◽  
Research Quality ◽  
Antenna Aperture ◽  
Dual Channel ◽  
Trade Offs ◽  
Radar Measurements ◽  
Airborne Phased Array Radar ◽  
Quality Measurements

Abstract. NCAR EOL is investigating potential configurations for the next-generation airborne phased array radar (APAR) that is capable of retrieving dynamic and microphysical characteristics of clouds and precipitation. The APAR will operate at C band. The APAR will use the electronic scanning (e-scan) feature to acquire the optimal number of independent samples for recording research-quality measurements. Since the airborne radar has only a limited time for collecting measurements over a specified region (moving aircraft platform ∼ 100 m s−1), beam multiplexing will significantly enhance its ability to collect high-resolution, research-quality measurements. Beam multiplexing reduces errors in radar measurements while providing rapid updates of scan volumes. Beamwidth depends on the size of the antenna aperture. Beamwidth and directivity of elliptical, circular, and rectangular antenna apertures are compared and radar sensitivity is evaluated for various polarimetric configurations and transmit–receive (T/R) elements. In the case of polarimetric measurements, alternate transmit with alternate receive (single-channel receiver) and simultaneous reception (dual-channel receiver) is compared. From an overall architecture perspective, element-level digitization of T/R module versus digital sub-array is considered with regard to flexibility in adaptive beamforming, polarimetric performance, calibration, and data quality. Methodologies for calibration of the radar and removing bias in polarimetric measurements are outlined. The above-mentioned engineering options are evaluated for realizing an optimal APAR system suitable for measuring the high temporal and spatial resolutions of Doppler and polarimetric measurements of precipitation and clouds.

scholarly journals Airborne polarimetric Doppler weather radar: Trade-offs between various engineering specifications

2017 ◽  
Author(s):  
Jothiram Vivekanandan ◽  
Eric Loew
Keyword(s):  
Single Channel ◽  
Adaptive Beamforming ◽  
Optimal Number ◽  
Research Quality ◽  
Antenna Aperture ◽  
Dual Channel ◽  
Trade Offs ◽  
Radar Measurements ◽  
Airborne Phased Array Radar ◽  
Quality Measurements

Abstract. NCAR/EOL is investigating potential configurations for the next generation airborne phased array radar (APAR) that is capable of retrieving dynamic and microphysical characteristics of clouds and precipitation. The APAR will operate at C-band. The APAR will use the electronic scanning (e-scan) feature to acquire the optimal number of independent samples for recording research quality measurements. Since the airborne radar has only a limited time for collecting measurements over a specified region (moving aircraft platform ~ 100 m/s), beam multiplexing will significantly enhance its ability to collect high-resolution, research quality measurements. Beam multiplexing reduces errors in radar measurements while providing rapid updates of scan volumes. Beamwidth depends on the size of the antenna aperture. Beamwidth and Directivity of elliptical, circular and rectangular antenna apertures are compared and radar sensitivity is evaluated for various polarimetric configurations and transmit/receive elements. In the case of polarimetric measurements, alternate transmit with alternate receive (single channel receiver) and simultaneous reception (dual channel receiver) is compared. From an overall architecture perspective, element level digitization of transmit/receive (T/R) module versus digital sub-array is considered with regard to flexibility in adaptive beamforming, polarimetric performance, calibration, and data quality. Methodologies for calibration of the radar and removing bias in polarimetric measurements are outlined. The above-mentioned engineering options are evaluated for realizing an optimal APAR system suitable for measuring the high temporal and spatial resolutions of Doppler and polarimetric measurements of precipitation and clouds.

Monaural Versus Binaural Discrimination for Normal Listeners

1963 ◽  
Vol 6 (3) ◽  
pp. 263-269 ◽  
Author(s):  
Richard G. Chappell ◽  
James F. Kavanagh ◽  
Stanley Zerlin
Keyword(s):  
Single Channel ◽  
Normal Hearing ◽  
Dual Channel ◽  
Recording Session ◽  
Monosyllabic Words ◽  
Image Separation ◽  
Test Materials ◽  
The Difference

Normal hearing adults demonstrated approximately 20% better intelligibility scores for monosyllabic words presented binaurally (with a background of conversation) than to these words presented monaurally. The test materials were recorded on dual-channel tape through two head-mounted microphones. These microphones were directed toward each of three speakers who in turn produced the monosyllabic words while two simultaneous conversations were carried on by four other participants. Throughout the recording session the experimenters attempted to preserve as naturalistic a situation as possible. The 18 subjects with normal hearing listened through earphones to a single channel of this tape presented monaurally and to both channels delivered binaurally. The difference between the monaural and binaural intelligibility scores is discussed in terms of image-separation in space.

scholarly journals A Privacy Protection Model of Data Publication Based on Game Theory

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Li Kuang ◽  
Yujia Zhu ◽  
Shuqi Li ◽  
Xuejin Yan ◽  
Han Yan ◽  
...  
Keyword(s):  
Privacy Protection ◽  
Stackelberg Game ◽  
Rapid Development ◽  
Optimal Number ◽  
Service Development ◽  
Lower Probability ◽  
Data Publication ◽  
Development Organization ◽  
Trade Offs ◽  
New Strategy

With the rapid development of sensor acquisition technology, more and more data are collected, analyzed, and encapsulated into application services. However, most of applications are developed by untrusted third parties. Therefore, it has become an urgent problem to protect users’ privacy in data publication. Since the attacker may identify the user based on the combination of user’s quasi-identifiers and the fewer quasi-identifier fields result in a lower probability of privacy leaks, therefore, in this paper, we aim to investigate an optimal number of quasi-identifier fields under the constraint of trade-offs between service quality and privacy protection. We first propose modelling the service development process as a cooperative game between the data owner and consumers and employing the Stackelberg game model to determine the number of quasi-identifiers that are published to the data development organization. We then propose a way to identify when the new data should be learned, as well, a way to update the parameters involved in the model, so that the new strategy on quasi-identifier fields can be delivered. The experiment first analyses the validity of our proposed model and then compares it with the traditional privacy protection approach, and the experiment shows that the data loss of our model is less than that of the traditional k-anonymity especially when strong privacy protection is applied.

scholarly journals Falsifiability Is Not Optional

2017 ◽  
Author(s):  
Etienne P. LeBel ◽  
Derek Michael Berger ◽  
Lorne Campbell ◽  
Timothy Loving
Keyword(s):  
Statistical Power ◽  
A Priori ◽  
Open Science ◽  
Research Quality ◽  
Original Research ◽  
Fine Grained ◽  
Psychological Phenomena ◽  
Trade Offs ◽  
Cumulative Knowledge ◽  
Improved Model

Finkel, Eastwick, and Reis (2016; FER2016) argued the post-2011 methodological reform movement has focused narrowly on replicability, neglecting other essential goals of research. We agree multiple scientific goals are essential, but argue, however, a more fine-grained language, conceptualization, and approach to replication is needed to accomplish these goals. Replication is the general empirical mechanism for testing and falsifying theory. Sufficiently methodologically similar replications, also known as direct replications, test the basic existence of phenomena and ensure cumulative progress is possible a priori. In contrast, increasingly methodologically dissimilar replications, also known as conceptual replications, test the relevance of auxiliary hypotheses (e.g., manipulation and measurement issues, contextual factors) required to productively investigate validity and generalizability. Without prioritizing replicability, a field is not empirically falsifiable. We also disagree with FER2016’s position that “bigger samples are generally better, but … that very large samples could have the downside of commandeering resources that would have been better invested in other studies” (abstract). We identify problematic assumptions involved in FER2016’s modifications of our original research-economic model, and present an improved model that quantifies when (and whether) it is reasonable to worry that increasing statistical power will engender potential trade-offs. Sufficiently-powering studies (i.e., >80%) maximizes both research efficiency and confidence in the literature (research quality). Given we are in agreement with FER2016 on all key open science points, we are eager to start seeing the accelerated rate of cumulative knowledge development of social psychological phenomena such a sufficiently transparent, powered, and falsifiable approach will generate.

scholarly journals Speed Calibration and Traceability for Train-Borne 24 GHz Continuous-Wave Doppler Radar Sensor

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1230
Author(s):  
Lei Du ◽  
Qiao Sun ◽  
Jie Bai ◽  
Xiaolei Wang ◽  
Tianqi Xu
Keyword(s):  
Continuous Wave ◽  
Doppler Radar ◽  
Single Channel ◽  
Full Range ◽  
Calibration Method ◽  
Simulation System ◽  
Radar Sensor ◽  
Dual Channel ◽  
Calibration Methods ◽  
24 Ghz

The 24 GHz continuous-wave (CW) Doppler radar sensor (DRS) is widely used for measuring the instantaneous speed of moving objects by using a non-contact approach, and has begun to be used in train-borne movable speed measurements in recent years in China because of its advanced performance. The architecture and working principle of train-borne DRSs with different structures including single-channel DRSs used for freight train speed measurements in railway freight dedicated lines and dual-channel DRSs used for speed measurements of high-speed and urban rail trains in railway passenger dedicated lines, are first introduced. Then, the disadvantages of two traditional speed calibration methods for train-borne DRS are described, and a new speed calibration method based on the Doppler shift signal simulation by imposing a signal modulation on the incident CW microwave signal is proposed. A 24 GHz CW radar target simulation system for a train-borne DRS was specifically realized to verify the proposed speed calibration method for a train-borne DRS, and traceability and performance evaluation on simulated speed were taken into account. The simulated speed range of the simulation system was up to (5~500) km/h when the simulated incident angle range was within the range of (45 ± 8)°, and the maximum permissible error (MPE) of the simulated speed was ±0.05 km/h. Finally, the calibration and uncertainty evaluation results of two typical train-borne dual-channel DRS samples validated the effectiveness and feasibility of the proposed speed calibration approach for a train-borne DRS with full range in the laboratory as well as in the field.

scholarly journals Configuring Green Infrastructure for Urban Runoff and Pollutant Reduction Using an Optimal Number of Units

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1528 ◽  
Author(s):  
Carlos Martínez ◽  
Arlex Sanchez ◽  
Roberto Galindo ◽  
Aelaf Mulugeta ◽  
Zoran Vojinovic ◽  
...  
Keyword(s):  
Green Infrastructure ◽  
Urban Runoff ◽  
Optimal Number ◽  
Volume Reduction ◽  
Pollution Load ◽  
Flood Volume ◽  
Runoff Reduction ◽  
Trade Offs ◽  
Load Peak ◽  
Peak Runoff

Green infrastructure (GI) has been regarded as an effective intervention for urban runoff reduction. Despite the growing interest in GI, the technical knowledge that is needed to demonstrate their advantages, cost, and performance in reducing runoff and pollutants is still under research. The present paper describes a framework that aims to obtain the optimal configuration of GI (i.e., the optimal number of units distributed within the catchment) for urban runoff reduction. The research includes an assessment of the performance of GI measures dealing with pollution load, peak runoff, and flood volume reduction. The methodological framework developed includes: (1) data input, (2) GI selection and placement, (3) hydraulic and water quality modelling, and (4) assessing optimal GI measures. The framework was applied in a highly urbanized catchment in Cali, Colombia. The results suggest that if the type of GI measure and its number of units are taken into account within the optimisation process, it is possible to achieve optimal solutions to reduce the proposed reduction objectives with a lower investment cost. In addition, the results also indicate a pollution load, peak runoff, and flood volume reduction for different return periods of at least 33%, 28%, and 60%, respectively. This approach could assist water managers and their stakeholders to assess the trade-offs between different GI.

scholarly journals Comparative Analysis of Fault-Tolerant Dual-Channel BLDC and SR Motors

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2489
Author(s):  
M. Korkosz ◽  
P. Bogusz ◽  
J. Prokop ◽  
B. Pakla ◽  
G. Podskarbi
Keyword(s):  
Comparative Analysis ◽  
Direct Current ◽  
Permanent Magnets ◽  
Single Channel ◽  
Fault Tolerant ◽  
Operating Conditions ◽  
Switched Reluctance ◽  
Dual Channel ◽  
Reluctance Motor ◽  
Two Machines

This article presents the results of a comparative analysis of two electronically commutated brushless direct current machines intended for fault-tolerant drives. Two machines designed by the authors were compared: a 12/14 dual-channel brushless direct current motor (DCBLDCM) with permanent magnets and a 12/8 dual-channel switched reluctance motor (DCSRM). Information is provided here on the winding configuration, the parameters, and the power converters of both machines. We developed mathematical models of the DCBLDCM and DCSRM which accounted for the nonlinearity of their magnetization characteristics in dual-channel operation (DCO) and single-channel operation (SCO) modes. The static torque characteristics and flux characteristics of both machines were compared for operation in DCO and SCO modes. The waveforms of the current and the electromagnetic torque are presented for DCO and SCO operating conditions. For DCO mode, an analysis of the behavior of both machines under fault conditions (i.e., asymmetrical control, shorted coil, and open phase) was performed. The two designs were compared, and their strengths and weaknesses were indicated.

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