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Vehicular communication is a key enabler in making Automated Vehicles (AVs) collaborate by sharing information, which complements on-board sensor information and facilitates precise vehicle control. This paper presents a tailored measurement campaign aimed at analyzing the performance of two vehicular communication technologies, namely IEEE 802.11p and LTE-V2X. Our study focuses on key metrics for cooperating AVs, such as end-To-end latency and packet delivery ratios. Additionally, we investigate the feasibility of channel coexistence, assessing the challenges associated with concurrent channel access. The results derived from field tests are correlated with simulations conducted on PLEXE and OpenCV2X, i.e., platforms used for simulating IEEE 802.11p and LTE-V2X, respectively. This combined methodology, comprising field tests and simulations, enables the attainment of replicable conclusions, which in turn enables better design choices.

Although Starlink has been rolled-out for several years, there is still a lack of knowledge regarding system details and performance characteristics. To address this, we perform a network layer measurement campaign utilizing precise times-Tamping to analyze throughput variations at multiple time scales, and infer system timing details. On larger timescales we quantify the diurnal variations where the throughput varies with the time of day. On the medium timescales we establish the likely frequency allocation and beam switching period to be 15 seconds. The associated connectivity disturbances contribute to severe link underutilization for single long-lived TCP flows, which typically reach only 46% of the estimated link capacity. On the sub-millisecond timescale our network layer measurements corroborate recent physical layer investigations of the Starlink frame timing, which is confirmed to be 1.33 ms. © 2023 Owner/Author(s).

Although Starlink has been rolled-out for several years, there is still a lack of knowledge regarding system details and performance characteristics. To address this, we perform a network layer measurement campaign utilizing precise times-Tamping to analyze throughput variations at multiple time scales, and infer system timing details. On larger timescales we quantify the diurnal variations where the throughput varies with the time of day. On the medium timescales we establish the likely frequency allocation and beam switching period to be 15 seconds. The associated connectivity disturbances contribute to severe link underutilization for single long-lived TCP flows, which typically reach only 46% of the estimated link capacity. On the sub-millisecond timescale our network layer measurements corroborate recent physical layer investigations of the Starlink frame timing, which is confirmed to be 1.33 ms. © 2023 Owner/Author(s).

Although Starlink has been rolled-out for several years, there is still a lack of knowledge regarding system details and performance characteristics. To address this, we perform a network layer measurement campaign utilizing precise times-Tamping to analyze throughput variations at multiple time scales, and infer system timing details. On larger timescales we quantify the diurnal variations where the throughput varies with the time of day. On the medium timescales we establish the likely frequency allocation and beam switching period to be 15 seconds. The associated connectivity disturbances contribute to severe link underutilization for single long-lived TCP flows, which typically reach only 46% of the estimated link capacity. On the sub-millisecond timescale our network layer measurements corroborate recent physical layer investigations of the Starlink frame timing, which is confirmed to be 1.33 ms. © 2023 Owner/Author(s).

Although Starlink has been rolled-out for several years, there is still a lack of knowledge regarding system details and performance characteristics. To address this, we perform a network layer measurement campaign utilizing precise times-Tamping to analyze throughput variations at multiple time scales, and infer system timing details. On larger timescales we quantify the diurnal variations where the throughput varies with the time of day. On the medium timescales we establish the likely frequency allocation and beam switching period to be 15 seconds. The associated connectivity disturbances contribute to severe link underutilization for single long-lived TCP flows, which typically reach only 46% of the estimated link capacity. On the sub-millisecond timescale our network layer measurements corroborate recent physical layer investigations of the Starlink frame timing, which is confirmed to be 1.33 ms. © 2023 Owner/Author(s).

Although Starlink has been rolled-out for several years, there is still a lack of knowledge regarding system details and performance characteristics. To address this, we perform a network layer measurement campaign utilizing precise times-Tamping to analyze throughput variations at multiple time scales, and infer system timing details. On larger timescales we quantify the diurnal variations where the throughput varies with the time of day. On the medium timescales we establish the likely frequency allocation and beam switching period to be 15 seconds. The associated connectivity disturbances contribute to severe link underutilization for single long-lived TCP flows, which typically reach only 46% of the estimated link capacity. On the sub-millisecond timescale our network layer measurements corroborate recent physical layer investigations of the Starlink frame timing, which is confirmed to be 1.33 ms. © 2023 Owner/Author(s).

This paper presents the failure analysis and diagnostic of a hydraulic turbine. Shortly after a maintenance revision the thrust bearing of the turbine was destroyed when the turbine was put into operation. The damaged bearing was examined and the possible causes discussed. To identify the problem that led to the failure of the thrust bearing, a comprehensive on-site measurement campaign was done. Vibrations, pressures, temperatures and operating parameters were acquired at different operating conditions of the turbine. The analysis of the data allowed to determine the source of the problem and to implement a solution., The authors would like to thank the company Endesa Generación and the XFLEX HYDRO 2020 research and innovation program under grant agreement No 857832FLEX., Peer Reviewed, Postprint (published version)

In cooperative relaying, intermediate stations are required to enhance the end-to-end transmission performance. The performance of the cooperative relaying scheme has been investigated theoretically and via computer simulations. However, cooperative relaying using transmit diversity techniques in actual environments has not been investigated thus far. This paper presents an experimental system for distributed cooperative relaying using space-time block code and evaluations of its transmission performances in real propagation channels. To this end, four wireless stations-specifically, one source, two relays, and one destination-were developed using analog transceivers and field-programmable gate arrays for real-time digital signal processing. Sample timing and frequency synchronizations among the four wireless stations were established by using the received signals as a reference. The end-to-end error performance of distributed cooperative relaying was compared to those of noncooperative relaying schemes, and the performances of three relaying schemes were evaluated quasisimultaneously in terms of their cumulative distribution functions of the bit-error ratios (BERs). The experimental results indicated that the BER performance of the two-hop distributed cooperative relaying scheme was substantially superior to those of noncooperative two-hop relaying schemes, including a route diversity scheme.

The study presents an investigation of Waves4Power’s WaveEL 3.0 wave energy converter (WEC). It was used as a reference for full-scale measurements of the mooring forces and buoy motions in a measurement campaign 2017 at an installation location off the coast of Runde in Norway. A numerical simulation model of the installation was developed in the DNV GL software SESAM. Unfortunately, the sea state conditions were not measured during the measurement campaign. Hence, a methodology was developed that used the recorded motion data to compute the sea state conditions at the test site. The simulated WEC motions based on the computed sea states agreed very well with the measured WEC motions. The measured and simulated mooring forces were compared under various environmental conditions. 3-hour sea state realizations are typically preferred in numerical simulations. However, influences from the tide at the test site showed that sea states were normally stationary for only 1–2 h. The measured and simulated average mooring forces agreed very well during 1-hour periods, whereas the simulations overestimated the mooring forces in 3-hour periods because of the tide. © 2020 The Author(s).

The study presents an investigation of Waves4Power’s WaveEL 3.0 wave energy converter (WEC). It was used as a reference for full-scale measurements of the mooring forces and buoy motions in a measurement campaign 2017 at an installation location off the coast of Runde in Norway. A numerical simulation model of the installation was developed in the DNV GL software SESAM. Unfortunately, the sea state conditions were not measured during the measurement campaign. Hence, a methodology was developed that used the recorded motion data to compute the sea state conditions at the test site. The simulated WEC motions based on the computed sea states agreed very well with the measured WEC motions. The measured and simulated mooring forces were compared under various environmental conditions. 3-hour sea state realizations are typically preferred in numerical simulations. However, influences from the tide at the test site showed that sea states were normally stationary for only 1–2 h. The measured and simulated average mooring forces agreed very well during 1-hour periods, whereas the simulations overestimated the mooring forces in 3-hour periods because of the tide. © 2020 The Author(s).

Narrowband powerline communication systems are widely used in many applications, such as smart metering devices, home automation and low-speed command and control systems. However, power lines were not designed for data transmission and they represent a harsh environment for communication. In the specific bibliography, it is possible to find studies that show the diverse issues of Narrowband Powerline Communication, being the impedance of the grid one of them. The main objective of the present work is to provide a study on the impedance of the grid over this communication band. This study was done in a University environment which has a diverse number of unknown loads, considering the variation with time and location. The data acquisition system developed to conduct the study is shown. The analysis of the results shows that the local grid exhibits issues as least as severe as the ones presented by other authors in different countries and environments., Los sistemas de comunicación por la red eléctrica de banda angosta son ampliamente utilizados en aplicaciones como medidores inteligentes, automatización de hogares, y sistemas de control y comando de baja velocidad, entre otras. Sin embargo, las redes eléctricas no fueron diseñadas para transmitir datos y representan un ambiente hostil para las comunicaciones. En la bibliografía específica se encuentran estudios que evidencian las diversas problemáticas de las comunicaciones por la red eléctrica de banda angosta, siendo la impedancia una de las más importantes. El principal objetivo de este trabajo es proveer un estudio de la impedancia de la red eléctrica para esta banda de comunicación. Este estudio fue realizado en un ambiente Universitario que contiene un número diverso de cargas desconocidas, considerando las variaciones con respecto al tiempo y la ubicación. Se describe el sistema de adquisición desarrollado a medida para hacer el relevamiento. El análisis de los resultados muestra que la impedancia de la red presenta problemas para la comunicación PLC al menos tan severos como los relevados en otros estudios realizados en diferentes países y entornos.

Narrowband powerline communication systems are widely used in many applications, such as smart metering devices, home automation and low-speed command and control systems. However, power lines were not designed for data transmission and they represent a harsh environment for communication. In the specific bibliography, it is possible to find studies that show the diverse issues of Narrowband Powerline Communication, being the impedance of the grid one of them. The main objective of the present work is to provide a study on the impedance of the grid over this communication band. This study was done in a University environment which has a diverse number of unknown loads, considering the variation with time and location. The data acquisition system developed to conduct the study is shown. The analysis of the results shows that the local grid exhibits issues as least as severe as the ones presented by other authors in different countries and environments., Los sistemas de comunicación por la red eléctrica de banda angosta son ampliamente utilizados en aplicaciones como medidores inteligentes, automatización de hogares, y sistemas de control y comando de baja velocidad, entre otras. Sin embargo, las redes eléctricas no fueron diseñadas para transmitir datos y representan un ambiente hostil para las comunicaciones. En la bibliografía específica se encuentran estudios que evidencian las diversas problemáticas de las comunicaciones por la red eléctrica de banda angosta, siendo la impedancia una de las más importantes. El principal objetivo de este trabajo es proveer un estudio de la impedancia de la red eléctrica para esta banda de comunicación. Este estudio fue realizado en un ambiente Universitario que contiene un número diverso de cargas desconocidas, considerando las variaciones con respecto al tiempo y la ubicación. Se describe el sistema de adquisición desarrollado a medida para hacer el relevamiento. El análisis de los resultados muestra que la impedancia de la red presenta problemas para la comunicación PLC al menos tan severos como los relevados en otros estudios realizados en diferentes países y entornos.

Distributed detection techniques of multiple-input multiple-output (MIMO) spatially multiplexed signals are studied in this paper. This system considered employs multiple mobile stations (MSs) to receive signals from a base station, and then share their received signal waveforms with collaborating MSs. In order to reduce the amount of traffic over the collaborating wireless links, distributed detection techniques are proposed, in which multiple MSs are in charge of detection by making use of both the shared signal waveforms and its own received waveform. Selection combining schemes of detected bit sequences are studied to finalize the decisions. Residual error coefficients in iterative MIMO equalization and detection are utilized in this selection. The error-ratio performance is elucidated not only by computer simulations, but also by offline processing using experimental signals recorded in a measurement campaign.

Terminal-collaborated multiple-input multiple-output (MIMO) reception with adaptive terminal selection schemes has been studied experimentally. In the experimental system, frequency-domain iterative MIMO equalization was employed, and its performance was evaluated by making use of recorded signal waveforms in a measurement campaign. In iterative signal processing, it is known that early stopping can control unnecessary iterations. In this letter, it is revealed that early stopping can not only reduce computational complexity, but also improve the bit error ratio performance of iterative processing. This is because early stopping prevents the iteration process from causing errors.

Collaborated multiple-input multiple-output reception is studied in this letter. This system employs multiple mobile stations (MSs) to receive signals from a base station, and then share their received signals among collaborated MSs. One of important research topic for this system is MS selection for collaboration. This letter presents the relation between the error rate performance of this system and antenna arrangements of the MS side in actual environments. The results suggest that MSs in collaboration can remain the same in terms of long-term average performance.

The packet error rate (PER) performance of space-time block code based multi-hop cooperative relaying is studied. In the case of multiple relays at each hop, a unique feature of the end-to-end PER performance can be observed up to 3rd hop. In this letter, an outdoor measurement campaign is conducted to verify this PER performance. In addition, a cooperative relaying scheme with received data sharing among relays is also examined. It is experimentally shown that PER at the 3rd hop is better than that of the 1st hop.

5G promises to usher in the industrial 4.0 era. In that era, intricately managed autonomous industrial sites with for example remotely controller equipment and autonomous units promise previously unseen levels of efficiency. Although such scenarios are elusive, they come with strict long-since established safety requirements. To uphold such requirements, intelligent industrial 5G networks, that actively take into account prevailing conditions and dynamics of the workers on the site, the equipment, and the network, are needed. Little is known about the dynamics of actual industrial 5G networks and the interplay between network performance and QoE. In this paper, as a step towards intelligent industrial 5G networks, we measure network performance for an industrial 5G network, and conduct QoE experiments with remote controlled industrial equipment on an operational site. The results revealed unexpected relationships between QoE and network performance that shows how important domain-specific knowledge is when researching intelligent industrial 5G networks.

Free-stream turbulence (FST) and its effect on boundary-layer transition is an intricate problem. Elongated unsteady streamwise streaks of low and high speed are created inside the boundary layer and their amplitude and spanwise wavelength are believed to be important for the onset of transition. The transitional Reynolds number is often simply correlated with the turbulence intensity (), and the characteristic length scales of the FST are often considered to have a small to negligible influence on the transition location. Here, we present new results from a large experimental measurement campaign, where both the and the integral length scale () are varied (

This article describes the development and experimental verification of an instrument fault accommodation (IFA) scheme for front and rear suspension stroke sensors in motorcycles equipped with electronically controlled semiactive suspension systems. In particular, the IFA scheme is based on the use of nonlinear autoregressive with exogenous inputs (NARX) neural networks (NNs) employed as soft sensors for feeding the suspension control strategy back with measurement even in the presence of faults occurred on the sensors. Different NN architectures have been trained and tuned by considering real data acquired during several measurement campaigns. The performance has been compared with that of the well-known half-car model (HCM). Very satisfying results allow the soft sensor to be really integrated into fault-tolerant control systems. In experimental road tests, an implementation of the proposed IFA scheme on a low-cost microcontroller for automotive applications showed to be in real time. In this article, these experimental results are shown to prove the good performance of the IFA scheme in different motorcycle operating conditions. © 1963-2012 IEEE.

This paper considers a multi-machine control system using power line communication (PLC). The signal-to-noise ratio (SNR) of PLC channels has cyclostationary features synchronous to the mains voltage. As a promising candidate of the multiple access scheme for the system, this paper proposes a synchronous code division multiple access (SCDMA) scheme that uses mains voltage as its system clock. By using orthogonal codes, the communication performance of each code-channel is equalized, and the worst-case performance is improved.

(c) 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works., [EN] A thorough measurement campaign in an indoor environment at the millimeter-wave band is carried out with an aim at characterizing the short-term fading channel in terms of its higher-order statistics. The measurements are conducted in a variety of scenarios, with frequencies ranging from 55 to 65 GHz, in line-of-sight and non-line-of-sight conditions, and combinations of horizontal and vertical polarizations at both the transmitter and the receiver. A number of fading models are tested, namely Rayleigh, Rice, Nakagami-m, alpha-mu, kappa-mu, eta-mu, and alpha-eta-kappa-mu. The main second-order statistics under analysis are the level crossing rate (LCR) and average fade duration (AFD) both given per distance unit. From the experimental data, the parameters of these statistics are estimated, and the corresponding curves of the theoretical models are compared with the empirical ones and the best model is selected. Additionally, the study of the very general distribution, namely alpha-eta-kappa-mu, is advanced, in which new expressions for time-/distance-domain LCR and Al-ll are derived using an envelope-based approach. Such an approach leads to integral-form formulations with much less computational complexity and computes rapidly compared with the already existing ones presented elsewhere, also given in the integral form. Furthermore, a series of expansion expression for the alpha-eta-kappa-mu time-/distance-domain LCR is then derived that improves even further the computational time.

[EN] A thorough millimeter-wave measurement campaign is carried out in an indoor environment with an aim at characterizing the short-term fading channel behavior. The measurements are conducted in a variety of scenarios, with frequencies ranging from 55 GHz to 65 GHz, in line-of-sight and non-line-of-sight conditions, and combinations of horizontal and vertical polarizations at both transmitter and receiver. A number of fading models are tested, namely Rayleigh, Rice, Nakagami-m, alpha-mu, kappa-mu, eta-mu, and alpha-eta-kappa-mu. The statistics under analysis are those characterizing the fading amplitude and the frequency selectivity. In particular, the probability density and cumulative distribution functions for the former and level crossing rate per bandwidth unit for the latter are the respective first-and second-order statistics used. To this end, from the experimental data, the parameters of the models are estimated and the corresponding theoretical curves are plotted and compared with the empirical ones. Whereas the required theoretical formulations of the first-order statistics of these models are already well known, those of the second-order statistics as well as these fitting process in such a band shown here are unprecedented in the literature.

(c) 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works., [EN] A thorough measurement campaign in an indoor environment at the millimeter-wave band is carried out with an aim at characterizing the short-term fading channel in terms of its higher-order statistics. The measurements are conducted in a variety of scenarios, with frequencies ranging from 55 to 65 GHz, in line-of-sight and non-line-of-sight conditions, and combinations of horizontal and vertical polarizations at both the transmitter and the receiver. A number of fading models are tested, namely Rayleigh, Rice, Nakagami-m, alpha-mu, kappa-mu, eta-mu, and alpha-eta-kappa-mu. The main second-order statistics under analysis are the level crossing rate (LCR) and average fade duration (AFD) both given per distance unit. From the experimental data, the parameters of these statistics are estimated, and the corresponding curves of the theoretical models are compared with the empirical ones and the best model is selected. Additionally, the study of the very general distribution, namely alpha-eta-kappa-mu, is advanced, in which new expressions for time-/distance-domain LCR and Al-ll are derived using an envelope-based approach. Such an approach leads to integral-form formulations with much less computational complexity and computes rapidly compared with the already existing ones presented elsewhere, also given in the integral form. Furthermore, a series of expansion expression for the alpha-eta-kappa-mu time-/distance-domain LCR is then derived that improves even further the computational time.

[EN] A thorough millimeter-wave measurement campaign is carried out in an indoor environment with an aim at characterizing the short-term fading channel behavior. The measurements are conducted in a variety of scenarios, with frequencies ranging from 55 GHz to 65 GHz, in line-of-sight and non-line-of-sight conditions, and combinations of horizontal and vertical polarizations at both transmitter and receiver. A number of fading models are tested, namely Rayleigh, Rice, Nakagami-m, alpha-mu, kappa-mu, eta-mu, and alpha-eta-kappa-mu. The statistics under analysis are those characterizing the fading amplitude and the frequency selectivity. In particular, the probability density and cumulative distribution functions for the former and level crossing rate per bandwidth unit for the latter are the respective first-and second-order statistics used. To this end, from the experimental data, the parameters of the models are estimated and the corresponding theoretical curves are plotted and compared with the empirical ones. Whereas the required theoretical formulations of the first-order statistics of these models are already well known, those of the second-order statistics as well as these fitting process in such a band shown here are unprecedented in the literature.

The upcoming migration of satellite services to higher bands, namely, the Ka‐ and Q/V‐bands, offers many advantages in terms of bandwidth and system capacity. However, it poses challenges as propagation effects introduced by the various atmospheric phenomena are particularly pronounced in these bands and can become a serious constraint in terms of system reliability and performance. This paper presents the goals, organisation, and preliminary results of an ongoing large‐scale European coordinated propagation campaign using the Alphasat Aldo Paraboni Ka/Q band signal payload on satellite, performed by a wide scientific consortium in the framework of a European Space Agency (ESA) project. The main objective of this activity is the experimental characterisation of the spatial and temporal correlation over Europe of the radio channel at Ka and Q band for future modelling activities and to collect data for development and testing of fading mitigation techniques.

This paper introduces an effective detector for wavelength-resolution SAR incoherent change detection. The detector is derived from Bayes' theorem. The input of the detector is the differences between surveillance and reference magnitude images simply obtained by a subtraction while the output is a summary of the detected changes. The proposed detector is tested with 24 CARABAS images that were obtained from the measurement campaign in northern Sweden in 2002. The testing results show that the detector can provide a high average detection probability, e.g., about 96%, with a very low false alarm rate, e.g., only 0.35 per square kilometer. © 2019 IEEE.

Existing wireless communication systems are not able to meet the stringent requirements for critical machine-to-machine communications regarding ultra-reliability and low-latency. Since increasing the communication reliability often comes at the price of increasing the latency as well, new mechanisms must be proposed that consider both challenges together. A promising approach, according to analytical work, is to increase the reliability by using cooperative diversity, where all stations within range help each other in the transmission process. Theoretical analyses, however, only provide a limited insight regarding the actual performance due to the strong assumptions they make to model such complex systems. In this paper, we thus evaluate the practical feasibility of ultra-reliable low-latency communication through cooperation by designing a data link protocol that incorporates a best relay selection mechanism. We implement our protocol in a real-world testbed, consisting of software-defined radios, to gain a better understanding of how future ultra-reliable low-latency systems should be designed and implemented. Our measurement campaigns show that at a given low target latency of 1 ms, we achieve a packet error rate between 10-5 and 10-7 with a standard 802.11a physical layer., Conference code: 139092; Export Date: 22 October 2018; Conference Paper; Funding details: DFG, Deutsche Forschungsgemeinschaft; Funding text: ACKNOWLEDGMENTS We would like to thank the DFG for the support within the Cluster of Excellence “Integrative Production Technology for High-Wage Countries”. REFERENCES.QC 20181022

Frequency scarcity due to demand of bandwidth in wireless communication can be resolved by knowledge of spectrum occupancy. Therefore different measurement campaigns were conducted for spectrum occupancy worldwide. It has been observed that large numbers of bands is underutilized. These bands can be utilized by a secondary user without interference. In this paper, Spectrum utilization has determined by conducting a campaign for measurement of spectrum occupancy in the Solapur city, India for 0.7 to 2.4 GHz frequency region. As per the analysis, Telecom cellular service band has highest spectrum occupancy while aeronautical radio, fixed satellite doesn’t have any utilization. Total average spectrum occupancy is 15.77%. These results are obtained by using circularly polarized wideband microstrip antenna in place of commercially available antennas for measurement campaign, which shows good agreement with occupancy results but with lower system complexity. The results propose that Solapur city would be a better choice for deployment of cognitive radio as emerging technology to share the unoccupied spectrum.

One of the main challenges for wireless body area networks (WBANs) is to evaluate realistic methods to generate channel models for new different purposes and various environments quickly and flexibly. Finite integration technique (FIT) has shown to be promising method for modeling channels characteristics in WBAN deployment scenarios. Applying simulation based channel modeling on the performance evaluations of the concrete-surrounded use scenarios have not been presented in the literature. In this paper, FIT-based channel modeling is applied on the performance evaluation of IEEE 802.15.6 based energy detector (ED) receiver designed for monitoring the symptoms of Parkinson’s disease. The first aim of this paper is to assess and compare the simulated channel impulse responses (CIRs) with the data from a measurement campaign. The second aim is to apply the simulated channel on the performance evaluations of the IEEE 802.15.6 based ED receivers. The obtained bit error rate (BER) performances are compared with BERs obtained using channel measurement data in the simulations. It is shown that performance obtained using FIT-based channel modeling corresponds to performance obtained using channel measurement data based channel modeling. The results of this paper further verify the statements that FIT is sufficiently applicable for WBAN channel modeling.

Actuator line and disc techniques are employed to analyse the wake obtained in the New Mexico wind turbine experiment. The New Mexico measurement campaign done in 2014 is a follow-up to the MEXICO campaign, which was completed in 2006. Three flow configurations in axial flow condition are simulated and both computed loads and velocity fields around the rotor are compared with detailed PIV measurements. The comparisons show that the computed loadings are generally in agreement with the measurements under the rotor's design condition. Both actuator approaches under-predicted the loading in the inboard part of blade in stall condition as only 2D airfoil data were used in the simulations. The predicted wake velocities generally agree well with the PIV measurements. In the experiment, PIV measurements are also provided close to the hub and nacelle. To study the effect of hub and nacelle, numerical simulations are performed both in the presence and absence of the hub geometry. This study shows that the large hub used in the experiment has only small effects on overall wake behaviour., QC 20170221

The Nordic prediction model from 1996 is still used for road traffic noise predictions and noise mapping purposes in many cases in Sweden. The model is restricted to A-weighted levels and the vehicle categories only take light and heavy vehicles into account. Weather conditions and ground effects are simplified. The subsequent Nord2000Road model can be used for noise predictions in more complex situations. Nord2000Road uses third octave bands, an advanced outdoor propagation model and more categories for vehicles and ground. Recently the CNOSSOS-EU model has been developed in Europe and can be used for noise mapping purposes according to the European Noise Directive in the future. CNOSSOS-EU uses octave bands and similar vehicle categories as Nord2000Road. The source model as well as the propagation model differs from Nord2000Road. In 2015, a measurement campaign of noise emission in real traffic was conducted in Sweden. This paper presents updated input data for the Nord2000Road source model as well as national Swedish correction terms for rolling noise in the CNOSSOS-EU model to better represent the recent measurement results.

The Nordic prediction model from 1996 is still used for road traffic noise predictions and noise mapping purposes in many cases in Sweden. The model is restricted to A-weighted levels and the vehicle categories only take light and heavy vehicles into account. Weather conditions and ground effects are simplified. The subsequent Nord2000Road model can be used for noise predictions in more complex situations. Nord2000Road uses third octave bands, an advanced outdoor propagation model and more categories for vehicles and ground. Recently the CNOSSOS-EU model has been developed in Europe and can be used for noise mapping purposes according to the European Noise Directive in the future. CNOSSOS-EU uses octave bands and similar vehicle categories as Nord2000Road. The source model as well as the propagation model differs from Nord2000Road. In 2015, a measurement campaign of noise emission in real traffic was conducted in Sweden. This paper presents updated input data for the Nord2000Road source model as well as national Swedish correction terms for rolling noise in the CNOSSOS-EU model to better represent the recent measurement results.

A robust and accurate positioning solution is required to increase the safety in GPS-denied environments. Although there is a lot of available research in this area, little has been done for confined environments such as tunnels. Therefore, we organized a measurement campaign in a basement tunnel of Linköping university, in which we obtained ultra-wideband (UWB) complex impulse responses for line-of-sight (LOS), and three non-LOS (NLOS) scenarios. This paper is focused on time-of-arrival (TOA) ranging since this technique can provide the most accurate range estimates, which are required for range-based positioning. We describe the measurement setup and procedure, select the threshold for TOA estimation, analyze the channel propagation parameters obtained from the power delay profile (PDP), and provide statistical model for ranging. According to our results, the rise-time should be used for NLOS identification, and the maximum excess delay should be used for NLOS error mitigation. However, the NLOS condition cannot be perfectly determined, so the distance likelihood has to be represented in a Gaussian mixture form. We also compared these results with measurements from a mine tunnel, and found a similar behavior.

In this paper a comparative study of two measurement campaigns carried out in Barcelona, Spain, and Pozna, Poland, to identify spectrum occupancy in different bands, is presented. In both cases the measurement setup was harmonized to obtain comparable results. The problem of efficient noise floor estimation was also considered and a pragmatic approach that takes into account both internal and ambient noise has been proposed. Obtained results show significant amount of unused spectrum, with similar results for both sites when analyzed globally (average spectrum occupancy of 27% in Pozna¿ and 22% in Barcelona). On the contrary, when going to the detailed analysis of some specific bands, more relevant differences are obtained. These differences have been observed mainly in the Terrestrial TRunked RAdio (TETRA) bands that in Poland are also used by Code Division Multiple Access (CDMA) 450, as well as in the bands of theGlobal System for Mobile communications (GSM) due to the effects of Universal Mobile Telecommunications System (UMTS) refarming in the 900 MHz band., Peer Reviewed, Postprint (published version)

Diesel engines produce harmful exhaust emissions and high exhaust noise levels. One way of mitigating both exhaust emissions and noise is via the use of after treatment devices such as Catalytic Converters (CC), Selective Catalytic Reducers (SCR), Diesel Oxidation Catalysts (DOC), and Diesel Particulate Filters (DPF). The objective of this investigation is to characterize and simulate the acoustic performance of different types of filters so that maximum benefit can be achieved. A number of after treatment device configurations for trucks were selected and measured. A measurement campaign was conducted to characterize the two-port transfer matrix of these devices. The simulation was performed using the two-port theory where the two-port models are limited to the plane wave range in the filter cavity. These models are implemented in SIDLAB Software for the simulation of low frequency sound propagation in ducts, and SIDLAB was used to predict the transfer matrix of the tested configurations. This paper presents guidelines for dividing these complicated systems into a number of simple 1D elements. Specifically, strategies for modeling the side inlet and outlet end caps are documented. The model takes about 15 minutes to set-up and 15 seconds to solve which demonstrates the power of using two-port techniques in modeling exhaust systems. The comparisons show good agreement between the measured and simulated transmission loss in the plane wave region., QC 20121018

Low power communications of sensor nodes operating in unlicensed bands are easily corrupted by transmissions of collocated wireless terminals whose interference can induce packet losses and consequently increase energy consumption of sensor devices. Dynamic spectrum access mechanisms can mitigate these problems however the energy aware design of these access schemes is a challenging task. In this paper we consider an energy constrained system comprising two sensor nodes that avoid interference by exploiting spectrum opportunities in the time domain. Using the distributions of idle period duration obtained during a measurement campaign we show how it is possible to design the access scheme deployed by sensors in an energy efficient manner. We compare different spectrum sensing strategies, showing that per-packet sensing results in significant energy overhead. We further provide a way for dimensioning the size of transmitted packets. Simulation results show that our approach outperforms other access strategies and allows to reduce energy consumption of 20 to 90 percent depending on channel conditions., QC 20140901

Cílem bakalářské práce je definování možností pro on-line měření hydraulických parametrů v in-situ na stokové síti. Bakalář zpracuje rešerši problematiky a provede měrnou kampaň odtokových parametrů na jednotné stokové síti., The aim of the bachelor's thesis is to define options for on-line measurement of hydraulic parameters in-situ on the sewer network. The bachelor will research the issue and carry out a measurement campaign of runoff parameters on a unified sewer network.

Cílem bakalářské práce je definování možností pro on-line měření hydraulických parametrů v in-situ na stokové síti. Bakalář zpracuje rešerši problematiky a provede měrnou kampaň odtokových parametrů na jednotné stokové síti., The aim of the bachelor's thesis is to define options for on-line measurement of hydraulic parameters in-situ on the sewer network. The bachelor will research the issue and carry out a measurement campaign of runoff parameters on a unified sewer network.