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- 2018
- spectral irradiance
- correlated color temperature
- double monochromator
- color rendering index
- Uncertainty of measurement
- Measurement and Control Technology and Instruments
- Brno University of Technology
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Pairwise nonclassical correlations for superposition of Dicke states via local quantum uncertainty and trace distance discord
摘要： The pairwise nonclassical correlations for two-qubit states, extracted from multi-qubit system with exchange symmetry and parity, are quanti?ed by local quantum uncertainty and trace distance discord. The explicit expressions of local quantum uncertainty and geometric trace distance discord for Dicke states and their superpositions are given. A comparison between the two quantum correlations quanti?ers is discussed.
关键词： Pairwise nonclassical correlations,Trace distance discord,Dicke states,Local quantum uncertainty
更新于2025-09-23 15:23:52
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Underwater optical wireless sensor networks using resource allocation
摘要： Optical wireless communications is an energy efficient and cost-effective solution for high speed and high secure wireless connections. In this paper, we propose an underwater optical wireless sensor network using multiple input multiple output technique and power allocation algorithm for supporting multiple users with the impacts of underwater channel uncertainty interferences. In proposed power allocation algorithm, all the LED nodes in are coordinated and controlled by a central controller; each LED node supports all the users within its field of view. To separate users, optical code division multiple access is used; cyclic optical orthogonal code working as CDMA code is employed. At the receiver, a minimal mean squared error (MMSE) filter is uniquely designed for each user. The MMSE filters and the assigned power can be jointly optimized to improve the overall throughput and signal to noise ratio. Since the system performance may be impacted by the underwater channel uncertainty, the proposed power allocation can use the predicted channel uncertainty variance to reduce the interference of the channel uncertainty and improve the signal to noise ratio. Compared to the equal power allocation algorithm, the proposed algorithm can support longer transmission distance, higher bit rate and lower bit error rate.
关键词： Multiple access interference,Underwater communications,Wireless sensor networks,Channel uncertainty,MIMO system,CDMA,Optical wireless communications,Resource allocation
更新于2025-09-23 15:23:52
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[IEEE 2018 26th European Signal Processing Conference (EUSIPCO) - Rome (2018.9.3-2018.9.7)] 2018 26th European Signal Processing Conference (EUSIPCO) - Uncertainty Quantification in Imaging: When Convex Optimization Meets Bayesian Analysis
摘要： We propose to perform Bayesian uncertainty quantification via convex optimization tools (BUQO), in the context of high dimensional inverse problems. We quantify the uncertainty associated with particular structures appearing in the maximum a posteriori estimate, obtained from a log-concave Bayesian model. A hypothesis test is defined, where the null hypothesis represents the non-existence of the structure of interest in the true image. To determine if this null hypothesis is rejected, we use the data and prior knowledge. Computing such test in the context of imaging problem is often intractable due to the high dimensionality involved. In this work, we propose to leverage probability concentration phenomena and the underlying convex geometry to formulate the Bayesian hypothesis test as a convex minimization problem. This problem is subsequently solved using a proximal primal-dual algorithm. The proposed method is applied to astronomical radio-interferometric imaging.
关键词： astronomical imaging,proximal primal-dual algorithm,inverse problem,hypothesis testing,Bayesian uncertainty quantification
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE Conference on Antenna Measurements & Applications (CAMA) - Va?ster?s (2018.9.3-2018.9.6)] 2018 IEEE Conference on Antenna Measurements & Applications (CAMA) - Guidelines for Millimeter-Wave Antenna Measurements
摘要： The characterization of physically small antennas in the millimeter-wave range has proven to be a challenge. Several research groups have developed new antenna measurement systems to be able to characterize millimeter-wave antennas. These measurement systems mainly focus on the establishment of a well-defined connection between test equipment and the antenna-under-test (AUT) for radiation pattern measurements. However, uncertainties affecting the measurement results are not always well understood. We have investigated the effect of misalignment, the effectiveness of an anechoic environment for frequencies up to 90 GHz and the impact of spurious radiation of the probe.
关键词： anechoic environment,probe radiation,60 GHz,probe connection,uncertainty analysis,alignment,Millimeter wave,antenna measurement
更新于2025-09-23 15:23:52
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[IEEE 2018 Seventh Balkan Conference on Lighting (BalkanLight) - Varna (2018.9.20-2018.9.22)] 2018 Seventh Balkan Conference on Lighting (BalkanLight) - Uncertainty Budget for Calibration of Luminance Meters for Measurement of Photopic Adaptation Luminance of Road Tunnels
摘要： The present paper represents uncertainty budget for calibration of luminance meters for road tunnels. There are several types of luminance meters calibrations which have different advantages and calibration setups. A description of the configuration for performance of calibrations of luminance meters used in TU Sofia is presented. The specific factors and their contribution in the mathematical model of the combined uncertainty for the used calibration method are observed. The calibration value is valid for the described measurement geometry and the proposed mathematical model. Conclusions are made for the different factors included in the uncertainty budget.
关键词： calibration,road tunnels,uncertainty,luminance meters
更新于2025-09-23 15:23:52
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Uncertainty analysis for ac–dc difference measurements with the AC Josephson voltage standard
摘要： A detailed analysis of the uncertainties obtained in ac–dc difference measurements with an AC Josephson voltage standard (ACJVS) is presented. For audio frequencies and for voltages less than 200 mV, ac–dc transfers with the ACJVS may reduce the combined uncertainty by factors of 2–10, compared with conventional methods based on thermal converters. Type A uncertainties are predominantly limited by the thermal transfer standard (TTS), or the digital voltmeter used to acquire the output voltage from the TTS. In agreement with earlier work, the transmission line is the primary contributor to Type B errors for frequencies above 10 kHz. A Monte Carlo sensitivity analysis is used to demonstrate how the uncertainties of transmission line impedance and on-chip inductance impact the accuracy of the rms amplitude conveyed to the TTS.
关键词： ac voltage metrology,transmission line analysis,Josephson junction arrays,quantum voltage standards,uncertainty analysis
更新于2025-09-23 15:22:29
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Uncertainty Quantification in Synthetic Aperture Radar Remote Sensing Data Processing
摘要： A new methodology, based on the International Organization for Standardization (ISO) Guide to the expression of Uncertainty in Measurement (GUM), for the analysis of uncertainties in Synthetic Aperture Radar (SAR) remote sensing data is presented. The principal idea is to assess the sources of uncertainty, developing computational approaches to propagate uncertainties through the whole SAR signal processing chain. The final goal is to construct uncertainties budgets to quantify the total uncertainty of SAR products, permitting their 'traceability' to international reference standards.
关键词： uncertainty,GUM,SAR
更新于2025-09-23 15:22:29
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Use of DEMs Derived from TLS and HRSI Data for Landslide Feature Recognition
摘要： This paper addresses the problems arising from the use of data acquired with two different remote sensing techniques—high-resolution satellite imagery (HRSI) and terrestrial laser scanning (TLS)—for the extraction of digital elevation models (DEMs) used in the geomorphological analysis and recognition of landslides, taking into account the uncertainties associated with DEM production. In order to obtain a georeferenced and edited point cloud, the two data sets require quite different processes, which are more complex for satellite images than for TLS data. The differences between the two processes are highlighted. The point clouds are interpolated on a DEM with a 1 m grid size using kriging. Starting from these DEMs, a number of contour, slope, and aspect maps are extracted, together with their associated uncertainty maps. Comparative analysis of selected landslide features drawn from the two data sources allows recognition and classification of hierarchical and multiscale landslide components. Taking into account the uncertainty related to the map enables areas to be located for which one data source was able to give more reliable results than another. Our case study is located in Southern Italy, in an area known for active landslides.
关键词： kriging,Geo-Eye-1,TLS,morphometric feature,HRSI,uncertainty,DEM
更新于2025-09-23 15:22:29
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Uncertainty Analysis and Experimental Design in the Monte Carlo Ray-Trace Environment
摘要： Despite the dominant role of the Monte Carlo ray-trace (MCRT) method in modern radiation heat transfer analysis, the contemporary literature remains surprisingly reticent on the uncertainty of results obtained using it. After first identifying the radiation distribution factor as a population proportion, standard statistical procedures are used to estimate its mean uncertainty, to a stated level of confidence, as a function of the number of surface elements making up the enclosure and the number of rays traced per surface element. This a priori statistical uncertainty is then shown to compare favorably with the observed variability in the distribution factors obtained in an actual MCRT-based analysis. Finally, a formal approach is demonstrated for estimating, to a prescribed level of confidence, the uncertainty in predicted heat transfer. This approach provides a basis for determining the minimum number of rays per surface element required to obtain the desired accuracy.
关键词： Monte Carlo ray-trace,uncertainty analysis,experimental design,radiation heat transfer,distribution factor
更新于2025-09-23 15:22:29
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Estimation of Uncertainty in the Lateral Vibration Attenuation of a Beam with Piezo-Elastic Supports by Neural Networks
摘要： Quantification of uncertainty in technical systems is often based on surrogate models of corresponding simulation models. Usually, the underlying simulation model does not describe the reality perfectly, and consequently the surrogate model will be imperfect. In this article we propose an improved surrogate model of the vibration attenuation of a beam with shunted piezoelectric transducers. Therefore, experimentally observed and simulated variations in the vibration attenuation are combined in the model estimation process, by using multi–layer feedforward neural networks. Based on this improved surrogate model, we construct a density estimate of the maximal amplitude in the vibration attenuation. The density estimate is used to analyze the uncertainty in the vibration attenuation, resulting from manufacturing variations.
关键词： Density estimation,neural network,uncertainty quantification,imperfect model,surrogate model
更新于2025-09-23 15:22:29