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[IEEE 2018 International Conference and Exposition on Electrical And Power Engineering (EPE) - Iasi, Romania (2018.10.18-2018.10.19)] 2018 International Conference and Exposition on Electrical And Power Engineering (EPE) - Analysis of Light Design in the Lighting Laboratory of the Riga Technical University
摘要： Given the fact that it is required to increase the efficiency of energy consumption in the premises, it is necessary to develop an effective lighting design that can be used both in old buildings and in new projects. To achieve a lower overall energy consumption by a building without sacrificing the quality of lighting, effective lighting modeling is needed, which allows to obtain reliable results for models as close as possible to real life, taking into account energy-saving lighting devices, integration of daylight in order to reduce energy consumption and maintenance costs, etc. The research evaluates possibility to measure luminance of light sources and detect sources of glare, using ordinary digital single-lens reflex camera (DSLR) and image editing software. Methodology and workflow is presented. The results then are discussed and ways to improve the accuracy of the measurements are highlighted.
关键词： visible spectrum,light measurements,digital camera,fluctuations,Dialux,glare
更新于2025-09-23 15:22:29
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Propagation Experiment at Ka-Band in French Guiana: First Year of Measurements
摘要： ONERA, the French Aerospace Lab, and CNES, the French Space Agency, are currently running a Ka-band propagation experiment at the Guiana Space Centre (CSG) in Kourou (French Guiana). A rain gauge and a beacon receiver able to record the 20.2 GHz beacon signal of the Amazonas 3 satellite have been deployed. The equipment is operational since January 1, 2017 and the duration of the experiment has been set to 3 years. This letter addresses some results of the first year of measurements (from January 2017 to December 2017). The annual and monthly Complementary Cumulative Distribution Functions of rainfall rate and rain attenuation are presented as well as a comparison with the rain attenuation prediction method recommended in ITU-R P.618-13.
关键词： Equatorial area,Ka-Band,Satellite communications,Propagation,Measurements
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 10th Sensor Array and Multichannel Signal Processing Workshop (SAM) - Sheffield (2018.7.8-2018.7.11)] 2018 IEEE 10th Sensor Array and Multichannel Signal Processing Workshop (SAM) - Multi-Layer Terahertz Imaging of Non-Overlapping Contents
摘要： This paper considers terahertz (THz) imaging of multi-layer non-overlapping contents with compressed measurements. One issue here is the shadow effect from front layers to deep layers due to the non-uniform penetrating illumination. In the case of non-overlapping contents in layered structures, the shadow effect can be utilized to improve recovery performance and reduce the number of measurements. To this end, we propose several approaches based on the total variation (TV) minimization principle and take into account individual-layer sparsity, group sparsity over layers, and hierarchical group sparsity over layers to reduce the number of measurements. Numerical evaluation confirms the effectiveness of the proposed approaches.
关键词： compressed measurements,content extraction,Terahertz,multi-layer structure
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 - Clear-Air Anomaly Detection Using Modified Kalman Temporal Filter from Geostationary Multispectral Data
摘要： A multispectral temporal-based remote sensing technique based on a modified Kalman filter is presented for clear-air detection by using Geostationary visible-infrared radiometric passive measurements. The Kalman estimate relies on a model of the daily measurement cycle of the considered pixel in clear-sky conditions. If the measurement significantly deviates from the predicted value, an anomaly is detected, which is interpreted as a non-clear air scenario. The add-on value of such approach is to be able to provide a-priori estimates, making the algorithm applicable in a global way. The Meteosat Second Generation satellite has been used over a large sample area in West Africa and a test period of three months. An inter-comparison with respect to the EUMETSAT cloud mask product has been carried out showing promising results in terms of detecting clear-air scenarios and percentages of matching around 90% over the entire period.
关键词： Geostationary Visible-Infrared satellite measurements,clear-air detection,Kalman filtering,environmental monitoring,Global-scale analysis
更新于2025-09-23 15:22:29
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Case Study of Empirical Beam Hardening Correction Methods for Dimensional X-ray Computed Tomography Using a Dedicated Multi-material Reference Standard
摘要： This paper presents a case study of two selected beam hardening correction methods and their effects on dimensional measurements of multi-material objects. The methods under test are empirical cupping correction (ECC) and empirical dual energy calibration (EDEC). These methods were originally developed for medical applications and their potential for the reduction of artefacts is typically only analysed based on grey value images. For testing and benchmarking of the mentioned methods for dimensional metrology, a dedicated multi-material reference standard—a multi-material hole cube—is used. This reference standard was originally developed for acceptance testing of CT systems. This paper shows a second application of this standard. The reference standard has been calibrated by tactile measurements to assess centre–centre distance errors as well as patch-based bidirectional length measurement errors on beam hardening corrected data and on uncorrected data. For the application of the method also to industrial multi-material scenarios, slight modifications of the ECC method are proposed. Practical aspects of both the ECC and the EDEC approaches as well as measurement results are analysed and discussed in detail. ECC was able to significantly improve dimensional measurements and was especially able to reduce extreme errors occurring in particular in multi-material scenarios by a factor of more than 4. EDEC, the dual-energy approach, reduced grey value inhomogeneities caused by artefacts even more. Its performance for dimensional measurements was however a little worse than ECC. EDEC data resulted in a slightly larger total range of residual measurement errors, mainly due to an elevated noise level.
关键词： Beam hardening correction,Industrial computed tomography,Multi-material measurements,Material influence,Dimensional metrology
更新于2025-09-23 15:22:29
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Interferometric surface mapping of a spherical proof mass for ultra precise inertial reference sensors
摘要： In the context of our investigations on novel inertial reference sensors for space applications, we have explored a design utilizing an optical readout of a spherical proof mass. This concept enables full drag-free operations, hence reducing proof mass residual acceleration noise to a minimum. The main limitations of this sensor are errors in position determination of the center of mass of the proof mass due to the surface topography and the involved path length changes upon rotation. One solution is to apply a surface map for correction of the measurement data, thus improving the precision of position determination. This article presents the results of our one-dimensional interferometric surface topography measurements of a sphere, achieving uncertainties of ≈10 nm, as a first step to realize a complete surface map. The measurement setup consists of two heterodyne interferometers positioned in an opposing configuration, which measure the surface topography while the sphere is continuously rotated by a rotation stage.
关键词： figure,roughness,Surfaces,Roughness,Interferometry,Surface measurements
更新于2025-09-23 15:22:29
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Temperature Measurement of Fluid Flows by Using a Focusing Schlieren Method
摘要： A method for measuring planar temperature fields of fluid flows is proposed. The focusing schlieren technique together with a calibration procedure to fulfill such a purpose is used. The focusing schlieren technique uses an off-axis circular illumination to reduce the depth of focus of the optical system. The calibration procedure is based on the relation of the intensity level of each pixel of a focused schlieren image to the corresponding cutoff grid position measured at the exit focal plane of the schlieren lens. The method is applied to measure planar temperature fields of the hot air issuing from a 10 mm diameter nozzle of a commercial Hot Air Gun Soldering Station Welding. Our tests are carried out at different temperature values and different planes along the radial position of the nozzle of the hot air. The experimental values of temperature measurements are in agree with those measured using a thermocouple.
关键词： temperature,focusing schlieren,measurements
更新于2025-09-23 15:22:29
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Automated daylight-linked control systems performance with illuminance sensors for side-lit offices in the Mediterranean area
摘要： Daylight-linked control systems (DLCSs) installation guarantees noticeable benefits, optimizing both energy saving and occupants' visual comfort. These systems performances are influenced by different factors, above all daylight availability. To deepen this issue, daylight illuminance measurements were performed at the work-plane and at the ceiling (corresponding to the position of a typical closed-loop photosensor) in a side-lit office during summer and winter. The office was equipped with two windows: one facing South and the other facing West. For each orientation, starting from measurements, the functioning of different closed-loop DLCSs was modelled. Results underlined that proportional dimming systems guarantee the best performances for each analyzed case, however they demonstrated that, for specific indoor daylight levels and task illuminances, switching systems can be profitable as well. It was underlined that, for specific daylight conditions, integral reset control guarantees performances comparable with those of proportional dimming. However, it was observed that for integral reset and multi-levels stepped systems, the risk that total illuminances (daylight plus electric light) are lower than the prescribed ones is higher than the other analyzed control strategies.
关键词： Daylight illuminance measurements,Mediterranean area daylighting,Automated daylight-linked control systems,Energy savings,Daylight
更新于2025-09-23 15:22:29
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Correlative infrared nanospectroscopy and transmission electron microscopy to investigate nanometric amyloid fibrils: prospects and challenges
摘要： Propagation of structural information through conformational changes in host-encoded amyloid proteins is at the root of many neurodegenerative disorders. Although important breakthroughs have been made in the field, fundamental issues like the 3D-structures of the fibrils involved in some of those disorders are still to be elucidated. To better characterise those nanometric fibrils, a broad range of techniques is currently available. Nevertheless none of them is able to perform direct chemical characterisation of single protein fibrils. In this work, we propose to investigate the structure of the C-terminal region of a bacterial protein called Hfq as a model amyloidogenic protein, using a correlative approach. The complementary techniques used are transmission electron microscopy and a newly developed infrared nanospectroscopy technique called AFM-IR. We introduce and discuss the strategy that we have implemented as well as the protocol, challenges and difficulties encountered during this study to characterise amyloid assemblies at the nearly single-molecule level.
关键词： correlative measurements,transmission electron microscopy,infrared nanospectroscopy,fibrils,Hfq,atomic force microscopy,Amyloid
更新于2025-09-23 15:22:29
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Autonomous Landing Control of Highly Flexible Aircraft based on Lidar Preview in the Presence of Wind Turbulence
摘要： This paper investigates preview-based autonomous landing control of a highly ?exible ?ying wing model using short range Lidar wind measurements in the presence of wind turbulence. The preview control system is developed based on a reduced-order linear aeroelastic model and employs a two-loop control scheme. The outer loop employs the LADRC (linear active disturbance rejection control) and PI algorithms to track the reference landing trajectory and vertical speed, respectively, and to generate the attitude angle command. This is then used by the inner-loop using H∞ preview control to compute the control inputs to the actuators (control ?aps and thrust). A landing trajectory navigation system is designed to generate real-time reference commands for the landing control system. A Lidar (light detection and ranging) simulator is developed to measure the wind disturbances at a distance in front of the aircraft, which are provided to the inner-loop H∞ preview controller as prior knowledge to improve control performance. Simulation results based on the full-order nonlinear ?exible aircraft dynamic model show that the preview-based landing control system is able to land the ?ying wing effectively and safely, showing better control performance than the baseline landing control system (without preview) with respect to landing effectiveness and disturbance rejection. The control system’s robustness to measurement error in the Lidar system is also demonstrated.
关键词： H∞ preview control,Highly ?exible aircraft,Lidar wind measurements,turbulence landing,autonomous landing control
更新于2025-09-23 15:22:29