Measurement-based Model Research Articles

TeraMIMO: A Channel Simulator for Wideband Ultra-Massive MIMO Terahertz Communications

Following recent advances in terahertz (THz) technology, there is a consensus on the crucial role of THz communications in the next generation of wireless systems. Aiming at catalyzing THz communications research, we propose TeraMIMO, an accurate stochastic MATLAB simulator of statistical THz channels. We simulate ultra-massive multiple-input multiple-output antenna configurations as critical infrastructure enablers that overcome the limitation in THz communications distances. We consider both line-of-sight and multipath components and propose frequency- and delay-domain implementations for single- and multi-carrier paradigms in both time-invariant and time-variant scenarios. We implement exhaustive molecular absorption computations based on radiative transfer theory alongside alternative sub-THz approximations. We further model THz-specific constraints, including wideband beam split effects, spherical wave propagation, and misalignment fading. We verify TeraMIMO by analogy with measurement-based channel models in the literature and ergodic capacity analysis. We introduce a graphical user interface and a guide for using TeraMIMO in THz channel generation and analyses.

Verification of blind quantum computation with entanglement witnesses

Verifiable blind quantum computation provides a cloud scenario for scalable quantum information processing. However, constructing one resource-efficient verification protocol is still an open problem. In this paper, the context of verification we consider is the measurement-based model, in which the client receives the graph state prepared by the server and performs single-qubit measurements on it to drive the computation. We first utilize three entanglement witnesses to estimate the fidelity of the prepared graph state. Applying entanglement witnesses to design the test phase, we propose verification protocols. Our protocol requires overhead in terms of copies of the graph state that scales as $O({n}^{2}logn)$, where $n$ is the number of qubits of the graph state. Furthermore, the soundness of our protocol is improved. The advantages of our protocol are derived from the fact that each entanglement witness can be implemented by the client with a fixed number of measurement settings.

Testing a 5G Communication System: Kriging-Aided O2I Path Loss Modeling Based on 3.5 GHz Measurement Analysis.

Deep knowledge of how radio waves behave in a practical wireless channel is required for the effective planning and deployment of radio access networks in outdoor-to-indoor (O2I) environments. Using more than 400 non-line-of-sight (NLOS) radio measurements at 3.5 GHz, this study analyzes and validates a novel O2I measurement-based path loss prediction narrowband model that characterizes and estimates shadowing through Kriging techniques. The prediction results of the developed model are compared with those of the most traditional assumption of slow fading as a random variable: COST231, WINNER+, ITU-R, 3GPP urban microcell O2I models and field measured data. The results showed and guaranteed that the predicted path loss accuracy, expressed in terms of the mean error, standard deviation and root mean square error (RMSE) was significantly better with the proposed model; it considerably decreased the average error for both scenarios under evaluation.

Simulated or measured soil moisture: which one is adding more value to regional landslide early warning?

Abstract. The inclusion of soil wetness information in empirical landslide prediction models was shown to improve the forecast goodness of regional landslide early warning systems (LEWSs). However, it is still unclear which source of information – numerical models or in situ measurements – is of higher value for this purpose. In this study, soil moisture dynamics at 133 grassland sites in Switzerland were simulated for the period of 1981 to 2019, using a physically based 1D soil moisture transfer model. A common parameterization set was defined for all sites, except for site-specific soil hydrological properties, and the model performance was assessed at a subset of 14 sites where in situ soil moisture measurements were available on the same plot. A previously developed statistical framework was applied to fit an empirical landslide forecast model, and receiver operating characteristic analysis (ROC) was used to assess the forecast goodness. To assess the sensitivity of the landslide forecasts, the statistical framework was applied to different model parameterizations, to various distances between simulation sites and landslides and to measured soil moisture from a subset of 35 sites for comparison with a measurement-based forecast model. We found that (i) simulated soil moisture is a skilful predictor for regional landslide activity, (ii) that it is sensitive to the formulation of the upper and lower boundary conditions, and (iii) that the information content is strongly distance dependent. Compared to a measurement-based landslide forecast model, the model-based forecast performs better as the homogenization of hydrological processes, and the site representation can lead to a better representation of triggering event conditions. However, it is limited in reproducing critical antecedent saturation conditions due to an inadequate representation of the long-term water storage.

Ultra-Reliable and Low-Latency 5G Systems for Port Automation

5G technology brings significant potential for enabling port automation, leading to improved flexibility, predictability, and safety in ports. In this article, we present main drivers and technologies required for port automation. We focus on future communication needs in ports and describe 5G communication networks with their ultra-reliable, low-latency, and high-capacity capabilities as a connectivity solution to forge the advanced technologies required to realize port automation. Extensive multi-cell simulations built on realistic measurement-based propagation models and prototype testing in lab and port environments demonstrate the 5G capabilities for ports.

Supporting Clinicians to Use Technology to Deliver Highly Personalized and Measurement-Based Mental Health Care to Young People: Protocol for an Evaluation Study.

BackgroundAustralia’s mental health care system has long been fragmented and under-resourced, with services falling well short of demand. In response, the World Economic Forum has recently called for the rapid deployment of smarter, digitally enhanced health services to facilitate effective care coordination and address issues of demand. The University of Sydney’s Brain and Mind Centre (BMC) has developed an innovative digital health solution that incorporates 2 components: a highly personalized and measurement-based (data-driven) model of youth mental health care and a health information technology (HIT) registered on the Australian Register of Therapeutic Goods. Importantly, research into implementation of such solutions considers education and training of clinicians to be essential to adoption and optimization of use in standard clinical practice. The BMC’s Youth Mental Health and Technology Program has subsequently developed a comprehensive education and training program to accompany implementation of the digital health solution.ObjectiveThis paper describes the protocol for an evaluation study to assess the effectiveness of the education and training program on the adoption and optimization of use of the digital health solution in service delivery. It also describes the proposed tools to assess the impact of training on knowledge and skills of mental health clinicians.MethodsThe evaluation study will use the Kirkpatrick Evaluation Model as a framework with 4 levels of analysis: Reaction (to education and training), Learning (knowledge acquired), Behavior (practice change), and Results (client outcomes). Quantitative and qualitative data will be collected using a variety of tools, including evaluation forms, pre- and postknowledge questionnaires, skill development and behavior change scales, as well as a real-time clinical practice audit.ResultsThis project is funded by philanthropic funding from Future Generation Global. Ethics approval has been granted via Sydney Local Health District’s Human Research Ethics Committee. At the time of this publication, clinicians and their services were being recruited to this study. The first results are expected to be submitted for publication in 2021.ConclusionsThe education and training program teaches clinicians the necessary knowledge and skills to assess, monitor, and manage complex needs; mood and psychotic syndromes; and trajectories of youth mental ill-health using a HIT that facilitates a highly personalized and measurement-based model of care. The digital health solution may therefore guide clinicians to help young people recover low functioning associated with subthreshold diagnostic presentations and prevent progression to more serious mental ill-health.International Registered Report Identifier (IRRID)PRR1-10.2196/24697

The performance of in‐building measurement‐based path loss modelling using kriging

An accuracy evaluation analysis of a novel in-building measurement-based path loss prediction narrowband model is presented here, comparing the performance of Kriging-aided shadowing prediction against the most traditional assumption of slow fading as a random variable and a classical estimation derived from linear interpolation. Extensive radio measurements were employed using distinct samples to calibrate (tuning dataset) and validate (testing dataset) the model. Path loss predictions are made over the testing dataset locations to compare it against the measured values, thus obtaining an error in the prediction from the difference between measurements and predictions. The results in the seven buildings evaluated show the potential of Kriging-aided channel modelling with a higher level of confidence than other modelling approaches compared hereafter.

Implementing a digital health model of care in Australian youth mental health services: protocol for impact evaluation

BackgroundThe World Economic Forum has recently highlighted substantial problems in mental health service provision and called for the rapid deployment of smarter, digitally-enhanced health services as a means to facilitate effective care coordination and address issues of demand. In mental health, the biggest enabler of digital solutions is the implementation of an effective model of care that is facilitated by integrated health information technologies (HITs); the latter ensuring the solution is easily accessible, scalable and sustainable. The University of Sydney’s Brain and Mind Centre (BMC) has developed an innovative digital health solution – delivered through the Youth Mental Health and Technology Program – which incorporates two components: 1) a highly personalised and measurement-based (data-driven) model of youth mental health care; and 2) an industrial grade HIT registered on the Australian Register of Therapeutic Goods. This paper describes a research protocol to evaluate the impact of implementing the BMC’s digital health solution into youth mental health services (i.e. headspace - a highly accessible, youth-friendly integrated service that responds to the mental health, physical health, alcohol or other substance use, and vocational concerns of young people aged 12 to 25 years) within urban and regional areas of Australia.MethodsThe digital health solution will be implemented into participating headspace centres using a naturalistic research design. Quantitative and qualitative data will be collected from headspace health professionals, service managers and administrators, as well as from lead agency and local Primary Health Network (PHN) staff, via service audits, Implementation Officer logs, online surveys, and semi-structured interviews, at baseline and then three-monthly intervals over the course of 12 months.DiscussionAt the time of publication, six headspace centres had been recruited to this study and had commenced implementation and impact evaluation. The first results are expected to be submitted for publication in 2021. This study will focus on the impact of implementing a digital health solution at both a service and staff level, and will evaluate digital readiness of service and staff adoption; quality, usability and acceptability of the solution by staff; staff self-reported clinical competency; overall impact on headspace centres as well as their lead agencies and local PHNs; and social return on investment.

Bridging the gap between measurement-based and simulation-based metamodels for deriving bulk optical properties from spatially-resolved reflectance profiles: effect of illumination and detection geometry.

Non-invasive determination of the optical properties is essential for understanding the light propagation in biological tissues and developing optical techniques for quality detection. Simulation-based models provide flexibility in designing the search space, while measurement-based models can incorporate the unknown system responses. However, the interoperability between these two types of models is typically poor. In this research, the mismatches between measurements and simulations were explored by studying the influences from light source and the incident and detection angle on the diffuse reflectance profiles. After reducing the mismatches caused by the factors mentioned above, the simulated diffuse reflectance profiles matched well with the measurements, with R2 values above 0.99. Successively, metamodels linking the optical properties with the diffuse reflectance profiles were respectively built based on the measured and simulated profiles. The prediction performance of these metamodels was comparable, both obtaining R2 values above 0.96. Proper correction for these sources of mismatches between measurements and simulations thus allows to build a simulation-based metamodel with a wide range of desired optical properties that is applicable to different measurement configurations.

Aircraft noise-Auralization-based assessment of weather-dependent effects on loudness and sharpness.

This paper deals with the question of how specific weather conditions affect the perception of aircraft noise. Auralization is a suitable method by enabling parametrical decompositions of the overall aircraft noise scenario into source and propagation components. Considering influences on the auditory perception, the signal processing chain contains different virtual receivers and post processing using psychoacoustic hearing models. For broad coverage, generic standardized as well as measurement-based atmosphere models with variation of ground impedances such as soil data are evaluated. These variations are given aircraft noise measurement values based on A-weighted sound pressure levels LA and psychoacoustic measures regarding loudness, N, and sharpness, S. The results show an immense influence of weather conditions on A-weighted sound pressure levels and on psychoacoustic perception of aircraft noise, too. The weather-dependent differences of A-weighted sound pressure levels are up to 15 dBA and relative differences regarding loudness of factor 1.6 and sharpness of factor 2.0 occur. The approach can be used to get a better understanding of how the temporal statistics of specific local weather conditions and their perceptual consequences may lead to improved taxation of actual noise events and to an improved basis for long-term averages of aircraft noise effects.

Genetic algorithm optimized node deployment in IEEE 802.15.4 potato and wheat crop monitoring infrastructure

This proposal investigates the effect of vegetation height and density on received signal strength between two sensor nodes communicating under IEEE 802.15.4 wireless standard. With the aim of investigating the path loss coefficient of 2.4 GHz radio signal in an IEEE 802.15.4 precision agriculture monitoring infrastructure, measurement campaigns were carried out in different growing stages of potato and wheat crops. Experimental observations indicate that initial node deployment in the wheat crop experiences network dis-connectivity due to increased signal attenuation, which is due to the growth of wheat vegetation height and density in the grain-filling and physical-maturity periods. An empirical measurement-based path loss model is formulated to identify the received signal strength in different crop growth stages. Further, a NSGA-II multi-objective evolutionary computation is performed to generate initial node deployment and is optimized over increased coverage, reduced over-coverage, and received signal strength. The results show the development of a reliable wireless sensor network infrastructure for wheat crop monitoring.

Performance analysis of in-band collision detection for dense wireless networks

With the massive growth of wireless networks comes a bigger impact of collisions and interference, which has a negative effect on throughput and energy efficiency. To deal with this problem, we propose an in-band wireless collision and interference detection scheme based on full-duplex technology. To study its performance, we compare its throughput and energy efficiency with the performance of traditional half-duplex and symmetric in-band full-duplex transmissions. Our analysis considers a realistic protocol and overhead modeling, and a measurement-based self-interference model. Our results indicate that our proposed collision detection scheme can provide significant gains in terms of throughput and energy efficiency in large wireless networks. Moreover, when compared to half-duplex and symmetric full-duplex, our analysis shows that this scheme allows up to 45% more nodes in the network for the same energy consumption per bit. These results suggest that this could be an enabling technology towards efficient, dense wireless networks.

There and back again: A circuit extraction tale

Translations between the quantum circuit model and the measurement-based one-way model are useful for verification and optimisation of quantum computations. They make crucial use of a property known as gflow. While gflow is defined for one-way computations allowing measurements in three different planes of the Bloch sphere, most research so far has focused on computations containing only measurements in the XY-plane. Here, we give the first circuit-extraction algorithm to work for one-way computations containing measurements in all three planes and having gflow. The algorithm is efficient and the resulting circuits do not contain ancillae. One-way computations are represented using the ZX-calculus, hence the algorithm also represents the most general known procedure for extracting circuits from ZX-diagrams. In developing this algorithm, we generalise several concepts and results previously known for computations containing only XY-plane measurements. We bring together several known rewrite rules for measurement patterns and formalise them in a unified notation using the ZX-calculus. These rules are used to simplify measurement patterns by reducing the number of qubits while preserving both the semantics and the existence of gflow. The results can be applied to circuit optimisation by translating circuits to patterns and back again.

Effect of measurement-based noise source model of military airplanes on the validity of aircraft noise estimation in Vietnam

Effect of measurement-based noise source model of military airplanes on the validity of aircraft noise estimation in Vietnam

Geometrical-Empirical Channel Propagation Model for Human Presence at 60 GHz

Previous efforts to develop simulation and/or measurement-based channel propagation models for the effect of human blockage on millimeter-wave communication systems have yielded important results, but lack either accuracy, generality, or simplicity. To fill that void, in this paper we propose a hybrid geometrical-empirical model for human presence; we refer to it as human presence because reflection from the body before and after blockage occurs in addition to diffraction around the body during blockage (as in previous efforts) is incorporated. Specifically, propagation is modeled as the superposition of the main transmission path and reflected and/or diffracted paths from the body; the geometrical component of the model accounts for the phase of each path while the empirical component accounts for its amplitude. To validate the proposed model and extract its empirical parameters, an exhaustive measurement campaign with 120 blockage scenarios, comprising varying human subjects and transmitter-human-receiver configurations, was conducted; a total of 180,000 channel acquisitions was recorded with our precision, state-of the-art 60-GHz channel sounder. The overall model is shown to be computationally efficient yet general enough to accurately represent a wide range of scenarios.

Innovative preclinic triage system to guide Australians to the right mental health care first time.

This paper presents a case study of an innovative direct-to-consumer preclinic triage system designed to reduce predicted peak demand for Australian mental health services as a result of COVID-19 and its associated socioeconomic consequences by guiding Australians to the right mental health care first time. Our innovative, digital health solution comprises two components: (1) a highly personalised and measurement-based model of care (Brain and Mind Centre model of care) that considers both the heterogeneity of mental disorders and other underlying comorbidities, as well as clinical staging; and (2) a health information technology (i.e. the InnoWell Platform). This digital health solution has been embedded as part of standard service delivery into a community-based intake service, thus resulting in a redesigned service model. The service model is currently being implemented as part of a pilot feasibility study, the marker of acceptability at the health professional and service level, and is now under active evaluation to determine its effect on outcomes for consumers, health professionals and the service. For the purposes of this paper, this model served as a prototype for the preclinic triage system that was conceptualised for national scalability at the primary health network level. When implemented at a national level, our direct-to-consumer preclinic triage system is expected to be an effective population health demand management strategy to address the rapidly emerging mental health demand crisis in Australia, and is aligned with the recent recommendation from the Productivity Commission to develop a sustainable national digital platform to facilitate the assessment and referral process to ensure access to mental health care matched to an individual's level of need. What is known about the topic? Although there is increased recognition of the mental health demand crisis in Australia as a result of the COVID-19 pandemic, little has been done to 'flatten' the curve. The Australian Government committed additional funding to support the Better Access Pandemic Support measure; however, this approach to care fails to appreciate both the disparities in service availability across Australia and the gap fees that are prohibitive to some of those seeking help. Furthermore, the expansion of this program may only result in those in care remaining in care, thus further delaying access to those in need. What does this paper add? This paper describes a digital health solution, comprised of a highly personalised and measurement-based model of care coupled with a health information technology, that has been embedded as part of standard service delivery. Consumers seeking mental health care complete a multidimensional self-report assessment via the technology, the results of which are available in real-time and used to facilitate triage to pathways of care as indicated by the severity of the consumer's illness and level of need to more effectively and efficiently allocate consumers to care. The redesigned service model is now under active evaluation to determine its effects on outcomes at consumer, health professional and service levels. What are the implications for practitioners? The redesigned local service model served as a prototype for our innovative direct-to-consumer preclinic triage system specifically designed to allocate consumers to self-management, ambulatory care or acute care based on clinical stage and level of need. It is our hypothesis that the preclinic triage system will be an effective population health demand management strategy. Importantly, the proposed preclinic triage system aligns with the recent recommendation from the Productivity Commission for the Australian Government to fund the development and sustained implementation of a digital platform to facilitate assessment and referral to evidence-based interventions matched to a consumer's level of need.

Market-Based Energy Management Model of a Building Microgrid Considering Battery Degradation

This article presents a model for energy management system of a building microgrid coupled with a battery energy storage. The model can be used to dispatch the battery as a flexible energy resource using a market-based setting. The battery is modeled considering battery degradation and real-life operation characteristics derived from measurements at a residential building. The performance of the model was evaluated first with simulations and integrated afterwards to an energy management system, which was demonstrated at a real residential building (HSB Living Lab) equipped with photovoltaic and battery storage systems. The simulation results showed that the building owner, and subsequently the residents, could benefit from the proposed model in reduced annual cost up to 3.1% under the considered pricing scheme. The demonstration results showed that dispatch under the measurement-based model could decrease the undelivered energy over the daily requested amount from the battery from 13.3% to 3.7%. Thus, the proposed model, which couples the measurement-based dispatch with battery degradation, can lead to a more accurate estimation of the building operation cost and an improved overall performance of battery as a flexible resource in building microgrids.

Global budget of atmospheric 129I during 2007–2010 estimated by a chemical transport model: GEARN–FDM

The behaviors of atmospheric 129 I and the global 129 I cycle remain incompletely understood because the spatiotemporal resolution of monitoring is insufficient, and few measurement-based models have been reported. This study aims to quantitatively understand the global 129 I budget. When quantifying, we conducted global atmospheric 129 I dispersion simulations covering from the period 2007 to 2010. To achieve this goal, the present study newly incorporates the iodine chemical processes of two gas-phase chemical reactions, six photolysis reactions, and two heterogeneous reactions into an existing atmospheric 129 I transport model (GEARN–FDM). In addition to the aerial release of 129 I from nuclear fuel reprocessing facilities, the model includes the volatilization processes of 129 I compounds from the Earth’s surface. The net 129 I exchange fluxes from the atmosphere to the Earth’s oceans and land were estimated to be 5.3 GBq/y and 18.0 GBq/y, respectively. The global 129 I emission from the oceans was estimated as 7.2 GBq/y, and nearly half of the emission totals are emitted from the English Channel (3.2 GBq/y). In addition, the global 129 I emissions from land are estimated to be 1.7 GBq/y. The remarkable 129 I emission levels from land mainly appear in Europe, Russia, and North America, and the emission distribution is impacted by the activities of past and ongoing nuclear fuel reprocessing facilities. The total 129 I emissions from the oceans and land are lower than the 129 I emissions from the model-included nuclear fuel reprocessing facilities (23.3 GBq/y), and show that the aerial releases from the nuclear fuel reprocessing facilities in operation are still important 129 I sources. • Heterogeneous, photolysis, and gas-phase reactions were implemented in GEARN–FDM. • GEARN–FDM captured the 129 I concentrations in rainfall in the Northern Hemisphere. • Aerial discharges from reprocessing facilities greatly impacts the 129 I budget. • Emissions from the English Channel are the largest oceanic source of 129 I. • Terrestrial emissions locally dominate 129 I deposition in North America.

Neutral Point Overvoltages in Wye-Wye Connected Distribution Transformer Caused by Lightning Current in Low-Voltage Winding

Lightning strokes are a main source of transformer failures in distribution systems. The discharge of a lightning current through a distribution transformer's high-voltage (HV) side arresters leads to a ground potential rise of the transformer tank. In the case of a wye-wye connected transformer with ungrounded HV neutral point, the ground potential rise can drive a current through the low-voltage (LV) side windings that leads to an excessive voltage in the HV side neutral point by inductive transformation. Simulations by a measurement-based model demonstrate that a voltage several times the lightning impulse test voltage can arise in the neutral point, in the case of a close lightning strike to the HV side overhead line. The use of transformer LV side surge arresters in combination with proper grounding on the HV-side are effective ways of reducing the neutral point overvoltage.

Measurements-Based Channel Models for Indoor LiFi Systems

Light-fidelity (LiFi) is a fully-networked bidirectional optical wireless communication (OWC) technology that is considered as a promising solution for high-speed indoor connectivity. Unlike in conventional radio frequency wireless systems, the OWC channel is not isotropic, meaning that the device orientation affects the channel gain significantly. However, due to the lack of proper channel models for LiFi systems, many studies have assumed that the receiver is vertically upward and randomly located within the coverage area, which is not a realistic assumption from a practical point of view. In this paper, novel realistic and measurement-based channel models for indoor LiFi systems are proposed. Precisely, the statistics of the channel gain are derived for the case of randomly oriented stationary and mobile users. For stationary users, two channel models are proposed, namely, the modified truncated Laplace (MTL) model and the modified Beta (MB) model. For mobile users, two channel models are proposed, namely, the sum of modified truncated Gaussian (SMTG) model and the sum of modified Beta (SMB) model. Based on the derived models, the impact of random orientation and spatial distribution of users is investigated, where we show that the aforementioned factors can strongly affect the channel gain and the system performance.