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In this article, a radio-frequency (RF) power-amplifier (PA) system configuration for the on-board energy conversion is proposed for unmanned aerial vehicle base station's (UAV-BS's) battery charging. First, the PA system utilizes the internal RF source for energy conversion so that perpetual battery charging is possible without external power sources. Therefore, a continuous battery charging of the UAV-BS is possible while providing wireless network coverage by hovering over the target location. In addition, the proposed PA system offers a higher RF power control resolution than the existing PA works, which is desirable for precise power control of the UAV-BS. The objective of simultaneous RF power control and battery charging by the PA system is achieved by activating one Wilkinson power divider (WPD) with a specific power splitting ratio in the power divider bank. The simulations show that the dynamic activation of ten distinct unequal split WPDs of the proposed PA system improves the RF power control resolution by $157$ and $396{\,}\%$ compared to the existing PAs. Additionally, the simulations show that the PA's power added efficiency fluctuation is reduced by $54$ and $82{\,}\%$ compared to the existing PAs. In addition, it will be shown that the proposed on-board battery charging increases the hovering time by $7.4{\,}\%$. Furthermore, an energy-efficiency optimization framework for UAV-BS's is proposed considering real-world communication system's hardware imperfections, and the proposed result suggests that UAV-BS's flight time may decrease by $50{\,}\%$ depending upon the type of UAV-BS RF components. [ABSTRACT FROM AUTHOR]

Using a well-known wiretap model, for the first time in this paper, closed-form solutions are achieved for wireless secrecy under dual correlated Rician fading. A novel wireless secrecy and end-to-end (e2e) system analysis employing decode-and-forward (DF) opportunistic relays and an adaptive encoder with on/off transmission are reported. A signal-to-noise ratio (SNR) distribution of dual correlated Rician fading is first obtained as a function of four nested infinite summations, which (i) converges for a finite number of terms, and (ii) is employed to compute secrecy outage probability for a passive wiretapper. Using two-dimensional Laplace transform of the SNR distribution of dual correlated Rician fading, an e2e system analysis is then given by deriving compact expressions for e2e SNR distributions, and e2e ergodic capacity. Relationships between important parameters are elaborated and explained. An asymptotic analysis and proof for infinite summation convergence are also given. It is shown that there is a trade-off between transmission quality and security via line-of-sight power. Simulation results are shown to match theoretical prediction, which validates this work. [ABSTRACT FROM AUTHOR]

Using the distributions of bivariate exponential-correlated Nakagami- $m$ , and Rician fading, this paper analyses opportunistic relay channel-state-information (CSI) outdatedness—written as “relay outdatedness” for brevity in this work—under two-degree-of-freedom (DoF) line-of-sight (LoS), and $n$ -DoF non-line-of-sight (NLoS), utilising maximal-ratio-combining (MRC) deployment under Rayleigh fading environments. End-to-end system performance under NLoS outdated-CSI (oCSI) conditions are also examined. Under the proposed generalised-oCSI conditions, a conditional distribution of Rayleigh fading is first obtained, from which the corresponding distribution of Rayleigh fading under MRC deployment can be derived. Detailed discussions are given, from which MRC appears to outperform selection combining diversity under generalised-oCSI conditions. Trade-off between key parameters is identified, and explained. Monte Carlo simulation is given, which is shown to match the proposed theoretical findings. [ABSTRACT FROM AUTHOR]

Distributions of colluding decode-and-forward (DF) opportunistic relays (ORs) employing maximal ratio combining under outdated channel state information (CSI) and independent and identically distributed (i.i.d.) generalized-Rician fading, including line-of-sight (LoS) fading, are fundamentally reported in this paper for the first time. DF-OR collusion can be initiated by employing a broadcast protocol at the destination. The new findings: 1) generalize existing findings under i.i.d. Rayleigh fading employing selection combining and 2) advance theoretical developments for wireless DF-OR networks. Mathematical expressions for: 1) average bit-error-rate of common modulation schemes and 2) ergodic channel capacity inner bounds are given in the compact infinite-summation form, which can be employed to assess the effectiveness of system coherence, a transmit signal-to-noise ratio, the number of DF ORs, degrees of freedom, and LoS power. Because of the LoS component under generalized-Rician fading, infinite summations must be mathematically employed, which are shown to fast converge for a finite number of terms, effectively realizing their practicality. Monte Carlo simulation results are also given under symbols, which match the proposed theoretical predictions. [ABSTRACT FROM AUTHOR]

Maximal ratio combiner output distributions of multivariate equal-correlated Nakagami- $m$ fading in their single-integral form are derived in this paper. The new distributions provide better alternatives to those obtained under selection combing (SC) diversity. Cross verification is mathematically performed to validate the proposed findings, which exactly reduce to existing results under SC deployment when the diversity order is neutralized. To show the effectiveness of the new findings, ergodic channel capacity is derived. Monte Carlo simulation is shown to match theoretical predictions. The new results diversify theoretical developments under equal-correlated Nakagami- $m$ fading, and initiate new directions for further progress. [ABSTRACT FROM AUTHOR]

To fulfil the needs of the future, the Australian building sector seems to contemplate toward sustainable design. A Green Star Environmental Rating System is one of many green-building rating systems that has been employed throughout the world. For this rating system, the “Material” category occupies 14% of credit points, which could be achieved from eight major categories. To help engineers and designers have simple tools to process sustainable projects, this paper develops a computer-aided model to calculate life-cycle greenhouse gas (GHG) emissions for conventional and high-strength concrete to maximize Credit 19B.1: Life-cycle impacts—Concrete in the Green Star Design and As Built in Australia. The model has been built under Microsoft Excel and Visual Basic platforms; thus, it is flexible and appears to be one of the effective ways to provide concrete mixture design using its life-cycle GHG emissions. Options to maximize Credit 19B.1 have also been discussed for normal and high-strength concrete. The model demonstrates the relationship between the utilization of supplementary cementitious material, coarse and fine aggregates used in concrete, a water-to-cement ratio with concrete strength, as well as sustainable points to be achieved. [ABSTRACT FROM AUTHOR]

This paper gives a novel perspective on physical layer security (PLS) and end-to-end (e2e) analysis under dual correlated Nakagami- $m$ fading, and outdated channel state information, by employing 1) decode-and-forward opportunistic relays, and 2) an adaptive encoder with on/off transmission. Assuming an infinite relay buffer size, two new sets of independent results for 1) non-integer fading parameter $m$ , mathematically employing infinite summations, and 2) integer $m$ , mathematically employing finite summations, are obtained. The adaptive encoder deployment improves transmission quality, and simultaneously enhances secrecy performance. The proposed e2e analysis coherently links secrecy, and e2e system performance for the first time under dual correlated Nakagami- $m$ fading. Findings for wireless secrecy, and e2e system analysis with the non-integer fading parameter $m$ offer an extra dimension to existing PLS literature, which has chronically been valid for only integer $m$. Convergence for infinite summations is achieved for a finite number of terms, realising the practicality of the proposed findings. Monte Carlo simulation successfully validates the new findings for non-integer $m$ , and an asymptotic analysis under several specific scenarios is also presented. [ABSTRACT FROM AUTHOR]

Using a distribution of a non-central chi-square random variable and selection combining, statistics of wireless systems employing decode-and-forward (DF) opportunistic relays (ORs) under outdated channel state information (CSI), and independent and identically distributed (i.i.d.) generalized-Rician fading environments are derived. By mathematically rewriting the Marcum $Q$ -function in its infinite-summation form, the distribution of non-central chi-square is mathematically simplified to its desirable form under different scenarios, which are then employed to compute average bit error rates for popular modulation schemes. Distributions of end-to-end system signal-to-noise ratio, useful for fifth-generation backhaul wireless communications, are also derived under integer and non-integer fading parameters. The new findings generalize existing findings employing DF ORs under i.i.d. Rayleigh fading environments. Mathematical predictions are shown to match simulation results. [ABSTRACT FROM AUTHOR]

Wireless secrecy under dual correlated Rician fading environments is theoretically studied for correlated source–destination and source–wiretapper channels. Without considering wiretapper active jamming capability, expressions for: 1) the ergodic secrecy capacity when the wiretapper is active and 2) secrecy outage probability when the wiretapper is passive are obtained. To further improve system security, new secrecy analyses employing an adaptive encoder with ON/OFF transmission are also given. The new findings exactly reduce to existing findings under dual correlated Rayleigh fading and advance theoretical developments for wireless secrecy under dual correlated Rician fading. Monte Carlo simulation results are given, which match theoretical predictions. Under wireless secrecy context, the disadvantage of line-of-sight (LoS) power and channel correlation is evidently shown, revealing the non-usefulness of LoS power and establishing a tradeoff between the transmission security and the transmission success. Benefits of a high-average transmit signal-to-noise ratio are discussed. [ABSTRACT FROM AUTHOR]

Exact secrecy and end-to-end (e2e) system analyses for cooperative wireless networks employing a best-relay-selection method with imperfect or outdated channel state information, an infinite relay buffer size, and a wire-tap channel under dualcorrelatedRayleigh fading are given. The new findings, which are valid for any value of the combined signal-to-noise ratio, generalize existing findings in the literature. Closed-form expressions for probability density function, cumulative distribution function, moment generating function, outage probability under secrecy, and e2e system performance are given using one- and two-dimensional Laplace transform. Secrecy outage probability employing an adaptive encoder is also derived, which coherently links secrecy performance and e2e system performance under dualcorrelatedRayleigh fading for the first time. Effects of amount of fading on secrecy are discussed. Simulation results are shown to match theoretical predictions. Detailed discussions and insight are also given. [ABSTRACT FROM AUTHOR]

To fulfil the hunger for sustainable development, Australian construction sector seems to contemplate toward green design. Green-Star environmental rating system, one of the active building rating systems in Australia, has also been employed in New Zealand, and South Africa. To help engineers and designers obtain comprehensive visualisation on sustainable projects, this paper develops a model to evaluate energy consumption and greenhouse-gas emissions based on typical Australian commercial building alternatives. From that, this paper explains how to achieve points for “Energy” and “Life-cycle impacts” categories of this rating system. The model uses GaBi 8.1 platforms and shows relationships between building's energy consumption, and greenhouse-gas emissions released during the building lifetime. This paper provides insight into life-cycle greenhouse-gas emissions assessment for several typical commercial building fabrics in Australia. The developed model can also be conveniently modified to automate calculations for other credits under the Green-Star environmental rating system, and other environmental rating systems around the world. The study suggests that designers should consider the inverse relationship between building envelopes' total R-value with energy consumption and greenhouse-gas emissions. Another finding shows that materials used for building envelopes play a significant role to manage energy consumption as well as greenhouse-gas emissions amount during the building's life-cycle. [ABSTRACT FROM AUTHOR]

Using a well-known wire-tap model, novel wireless secrecy analyses under dual correlated Nakagami- $m$ fading with a real fading parameter $m$ are reported. Infinite summations for incomplete gamma functions are employed to derive compact expressions for secrecy capacity and secrecy outage probability (SOP) under noninteger $m$. Independently, using finite summations, corresponding closed-form findings for integer $m$ are also derived. In the current literature, finite summations for the incomplete gamma functions, whose first arguments and hence $m$ must be an integer, are employed to obtain closed-form expressions for, first, the SOP (with an unknown passive wire-tapper's channel state information), and second, ergodic secrecy capacity (with partially known active wire-tapper's channel state information under slow fading). The new secrecy results for noninteger $m$ generalize the proposed findings for integer $m$ , and existing findings under dual correlated Rayleigh fading for $m=1$. The new findings can thus be comprehensively employed for wireless secrecy computation under dual correlated Nakagami- $m$ fading for real $m$. Infinite-summation convergence and cross verification are also obtained for a finite number of terms, which shows the practicality and consistency of the new findings. For the first time, secrecy analyses employing an adaptive encoder with on/off transmission are performed under dual correlated Nakagami- $m$ fading for real $m$ to not only improve wireless secrecy, but also achieve the eventual successful transmission from a source to a destination. The new SOP results for real $m$ can be employed as lower bounds and complete theoretical secrecy analyses, for SOP under dual correlated Nakagami- $m$ fading with integer $m$. Simulation results are employed to show matching between the proposed findings and existing findings. [ABSTRACT FROM AUTHOR]

Under even degrees of freedom, new single-integral and infinite-summation selection combiner output signal-to-noise ratio and signal-to-interference-and-noise ratio distributions of multivariate equally-correlated generalised-Rayleigh fading for multiuser-multiple-input-multiple-output (MU-MIMO) systems are obtained. The proposed findings can be employed to approximate intractable distributions of multivariate exponentially-correlated Rician fading. An average bit error rate of the differential binary phase-shift keying scheme for MIMO networks is derived using the new distributions, showing their efficiency for network assessment. [ABSTRACT FROM AUTHOR]

Obtaining tractable and compact expressions for cumulative distribution functions (cdfs) of multivariate correlated fading has long been difficult in wireless communications. Selection combiner output (SCO) single-user cdfs of multivariate correlated and identically distributed (c.i.d.) or equally-correlated Rayleigh, Rician, and Nakagami- $m$ fading for only even integer $n$-degree-of-freedom (DoF) noncentral chi-square distributed received signal envelopes have been studied in the literature. New infinite-summation and single-integral single-user single-input multiple-output (SIMO) SCO cdfs of multivariate c.i.d. generalised-Rician fading for any integer $n$ DoF noncentral chi-square, i.e., $n$ can be even and odd, are obtained in this paper. The new distributions, first, generalize existing results; second, can be extended for c.i.d. single-user and multiuser multiple-input multiple-output environments; and third open up new research directions in this topic. Detailed mathematical proof, discussions, and simulation results are given. [ABSTRACT FROM AUTHOR]

Solar electricity that is produced from photovoltaic solar systems has the potential to deliver clean sustainable energy. Positive steps are being undertaken to minimise greenhouse gas emissions in Australia and photovoltaic solar systems are contributing towards sustainability. The current amount of installed photovoltaic solar systems cannot address the global warming issues in whole, however renewable energy production is contributing towards minimising carbon emissions. One of the main concerns for the residential householders is the economic issue on the use of photovoltaic solar systems. This paper examines life cycle cost effectiveness in using photovoltaic solar systems with capacities ranging from 1.5 kW to 5 kW in relation to the number of occupants and consumption for residential dwellings over a 25-year period. Eight major cities in Australia, including Sydney, Canberra, Melbourne, Brisbane, Hobart, Adelaide, Darwin and Perth, are investigated. Life cycle cost comparisons among different types of electricity grid connected systems, including a gross-feed-in-tariff (GFIT) scheme, a net-feed-in-tariff (NFIT) scheme and a buy-back scheme, are also explored. It is found that all major cities can receive life cycle cost saving in installing photovoltaic solar systems in their residential dwellings. The life cycle cost saving is between $273 and $53,021 and the percentage of cost saving is between 0.35% and 123.83% in a 15-year period. It appears that the GFIT and NFIT schemes offer better benefits than the buy-back scheme in installing photovoltaic solar systems. It is also found that the higher the capacity of the photovoltaic solar systems, the higher the life cycle cost saving can be received. This paper contributes to prove the cost effectiveness of using photovoltaic solar systems with the example from Australian residential dwellings. [ABSTRACT FROM AUTHOR]

A simple and energy-efficient communication system configuration is proposed for Unmanned Aerial Vehicle Energy Transmitters (UAV-ETs) for Wireless Power Transfer (WPT) applications. The results show that the proposed UAV-ET's hardware configuration improves WPT time by 9. 305 % , and reduces UAV-ET's power consumption by 7. 47 % compared to the UAV Base Stations (UAV-BSs). Also, in the prior works on UAV-enabled WPT the UAV-ET's communication system configuration was not proposed, and UAV-ET's radio frequency component's real-world imperfections were ignored. Therefore, the work proposes a holistic energy efficiency optimization framework for UAV-ETs and hardware design parameters for qualifying the UAV-ET's hardware components to maximize UAV-ET's WPT time. Additionally, a three-dimensional UAV-ET placement optimization is proposed for maximizing WPT time, and results show that higher UAV-ET heights above the Wireless Energy-Receivers (WERs) decrease the WPT time by 4. 75 %. Besides, the results suggest that Antenna Array (AA) losses and the power amplifier's power added efficiency variation reduce UAV-ET's WPT time by 16. 48 %. Finally, a 115 g crossed-slotted waveguide AA for UAV-ET is manufactured using laser cutting, and the experiments confirm that the AA's total loss is 0.72 dB, therefore, the AA qualifies requirements according to the proposed UAV-ET's hardware component design optimization framework. • An aerial energy transmitter communication system configuration is proposed. • Framework to minimize power consumption of aerial energy transmitters proposed. • The framework considers realistic hardware imperfections. • A low-loss aerial energy transmitter antenna array is manufactured. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Distribution Functions of Selection Combiner Output in Equally Correlated Rayleigh, Rician, and Nakagami-m Fading Channels" by Y. X. Chen and colleagues is presented.

Single-integral expressions for cumulative distribution functions of multivariate correlated Rayleigh and Rician fading are studied. Mathematical mistakes in the literature are identified and corrected. Corrections are cross-verified against well-known findings in the literature, which can be employed to advance further theoretical developments for correlated fading. [ABSTRACT FROM AUTHOR]

SUMMARY This paper studies four aspects of multipath propagation with randomly distributed scatterers: (i) Gaussian and hyperbolic time-of-arrival (ToA) probability density functions (pdfs); (ii) theoretical bounds on the ToA pdfs; (iii) geometric pdfs in multipath propagation via Gaussian and hyperbolic scattering channels; and (iv) implementation of selective combining diversity as a method to decrease propagation delay, thus improving transmission performance. The Gaussian and hyperbolic scattering channels are employed to model random scatterers between a base station and a user equipment. One-dimensional and three-dimensional results of Gaussian and hyperbolic ToA pdfs are reported. Detailed discussions are given. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In the current age of enhanced environmental awareness, transformation to sustainable management in the construction sector is needed. China currently produces the largest amount of construction and demolition (C&D) waste around the world, but the average recovery rate of the waste was only about 5% in 2017. In order to investigate problems in current C&D waste management in China, a cross-national comparative analysis is conducted among China and seven selected countries (Japan, South Korea, Germany, Italy, Austria, the Netherlands and the United Kingdom), to compare legal texts of national policies and laws which relate to C&D waste management and are currently being used. Through the comparison, problems in management of C&D waste in China are investigated. The problems could be concluded to: (a) inadequate guidance on recycling, (b) lack of market incentives in utilising recycled materials, (c) incomplete knowledge of stakeholders' responsibilities, (d) lack of penalty for other stakeholders, and (e) inefficient supervision system. By understanding these problems, this paper further provides recommendations to enhance the performance of C&D waste management in China. [ABSTRACT FROM AUTHOR]

Carbon-conditioning or chemical permeation methods can provide excellent microstructural improvements to recycled concrete and brick aggregate; however, the applications have their limitations. Further, recycled brick aggregate cannot be effectively carbon-conditioned with conventional methods as it contains only trace amounts of reactive materials. It is therefore a necessity to use hybrid methods involving dual technologies combining carbon-conditioning and chemical permeation for its improvement. This paper is focused on developing a novel hybrid method for improving the microstructural properties of recycled concrete aggregate and recycled brick aggregate for concrete usage. This study conducts particle density, water absorption and crushing value tests to measure the physical improvements achieved with the novel hybrid method, and utilises a variety of chemicals and a reaction chamber for carbon-conditioning for aggregate treatment. The study evinces that both the recycled concrete aggregate and recycled brick aggregate experienced significant improvements, with 10 mm and 20 mm recycled concrete aggregate and 10 mm recycled brick aggregate exceeding the density of virgin aggregate. Magnesium hydroxide plus carbon dioxide (Mg(OH)2 (s) + CO2 (g)) treatment for recycled concrete aggregate and calcium hydroxide plus magnesium hydroxide plus carbon dioxide (Ca(OH)2 (s) + Mg(OH)2 (s) + 2CO2 (g)) treatment for recycled brick aggregate can be considered as potential candidates for optimal hybrid treatment methods. [ABSTRACT FROM AUTHOR]

Photo‐catalysis by small‐molecules is often limited by catalyst degradation and low electron‐transfer efficiency. Herein we report a stable N‐phenyl‐phenothiazine (PTH)‐derived porous coordination cage (PCC) as a highly efficient photocatalyst. By the incorporation of the photocatalytic PTH moiety into a PCC, aggregation‐induced quenching (AIQ) was shown to be reduced. An improvement in catalyst stability was discovered, ascribed to the synergistic effects of the PTH moieties. The catalyst, operating through a photolytic single‐electron transfer, was utilized for photo‐catalyzed dehalogenation and borylation. Evaluation of the catalytic mechanism in the borylation reaction showed that the improved performance results from the more efficient formation of the electron donor‐acceptor (EDA) complex with the cage. This discovery provides a potential strategy to improve the photophysical properties and stabilities of small‐molecule organic photocatalysts via supramolecular chemistry. [ABSTRACT FROM AUTHOR]

Photo‐catalysis by small‐molecules is often limited by catalyst degradation and low electron‐transfer efficiency. Herein we report a stable N‐phenyl‐phenothiazine (PTH)‐derived porous coordination cage (PCC) as a highly efficient photocatalyst. By the incorporation of the photocatalytic PTH moiety into a PCC, aggregation‐induced quenching (AIQ) was shown to be reduced. An improvement in catalyst stability was discovered, ascribed to the synergistic effects of the PTH moieties. The catalyst, operating through a photolytic single‐electron transfer, was utilized for photo‐catalyzed dehalogenation and borylation. Evaluation of the catalytic mechanism in the borylation reaction showed that the improved performance results from the more efficient formation of the electron donor‐acceptor (EDA) complex with the cage. This discovery provides a potential strategy to improve the photophysical properties and stabilities of small‐molecule organic photocatalysts via supramolecular chemistry. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) are hybrid materials known for their nanoscale pores, which give them high surface areas but generally lead to poor electrical conductivity. Recently, MOFs with high electrical conductivity were established as promising materials for a variety of applications in energy storage and catalysis. Many recent reports investigating the fundamentals of charge transport in these materials focus on the role of the organic ligands. Less consideration, however, is given to the metal ion forming the MOF, which is almost exclusively a late first‐row transition metal. Here, we report a moderately conductive porous MOF based on trivalent gallium and 2,3,6,7,10,11‐hexahydroxytriphenylene. Gallium, a metal that has not been featured in electrically conductive MOFs so far, has a closed‐shell electronic configuration and is present in its trivalent state—in contrast to most conductive MOFs, which are formed by open‐shell, divalent transition metals. Our material, made without using any harmful solvents, displays conductivities on the level of 3 mS/cm and a surface area of 196 m2/g, comparable to transition metal analogs. [ABSTRACT FROM AUTHOR]

The Hong Kong government has implemented various measures to reduce waste, including a waste disposal ordinance, a green manager scheme, a waste reduction framework plan, a pilot concrete recycling plant, waste management systems and a landfill charging scheme. However, there are difficulties in implementing the waste management systems for contractors. This paper examines the existing implementation of waste management systems in the Hong Kong construction industry. Major sources of construction waste, awareness to install environment-friendly activities, benefits, difficulties and recommendations in the implementation of waste management systems are discussed. Questionnaire survey and structured interviews are conducted. Power spectra and bispectra of the survey data are introduced to assess the implementation of the existing waste management systems. It is found that formwork and temporary hoardings are the major sources of construction waste. Improving environmental performance is ranked as the least project scope for construction projects. “Propose methods for reducing waste” is the major benefit gained. However, “Lack of well-known effective waste management methods” is the major difficulty encountered by organisations. “Use of metal formwork”, “Use of prefabricated building components” and “Use of non-timber hoarding” are the recommended methods to improve the existing implementation of waste management systems. [ABSTRACT FROM AUTHOR]

This paper proposes a hyperbolic distribution to model the distribution of random scatterers between a base station (BS) and the user equipment (UE) in multipath mobile environments. New hyperbolic angle-of-arrival (AoA) probability density function (pdf), power azimuth spectrum (PAS), time-of-arrival (ToA) pdf, and power delay spectrum (PDS) are derived. The effectiveness of Gaussian, Janaswamy, and hyperbolic scatterer distributions is assessed by estimating their fitting errors to a given empirical data set. New 3-D simulation results on the Gaussian and hyperbolic PAS and PDS are given and discussed. The line-of-sight (LoS) distance D (in kilometers) between the BS and the UE and the propagation path distance μ (in kilometers) can be related mathematically. [ABSTRACT FROM AUTHOR]

An estimate of the lower-bound on signal-to-noise ratio (SNR) of the nth-order hyperbolic time–frequency kernel is given. The effects of kernel parameters such as β, τ, n and a on the SNR are discussed. In particular, the direct relationship between the SNR and auto-term slope a is studied in detail. Conditions under which the lower-bound on SNR is obtained are derived. Preliminary observations on a transfer function model with the auto-term slope a and β as inputs, and lower-bound on SNR as output are given. Possible further work is outlined. [Copyright &y& Elsevier]

This paper studies the noise robustness of Laplace of hyperbolic (LoH) and Laplace of Gaussian (LoG) wavelets. A typical example of using the LoH and LoG to study Duffing oscillation under normal and noisy conditions is given. Relative merits of each method are discussed. [Copyright &y& Elsevier]

The Gaussian distribution and the 6σ principle have been widely used in the field of construction quality management with great success. This paper proposes a theoretical study on a new hyperbolic distribution using the 6σ principle to improve quality in construction management. The hyperbolic and Gaussian distributions are then numerically compared by estimating their important statistical properties, such as population in range, number of defects, yield percentage, and defects per million opportunities. The impacts of these factors are briefly discussed to give guidance to organizations in the construction industry on how to lower cost and improve project quality by prevention. A case study showing the cost data of a construction consultant company is presented. The data’s population in range and defects per million opportunities are estimated using Gaussian and hyperbolic distributions. In this particular case study, the hyperbolic distribution is shown to be more effective in quality improvement by prevention than the Gaussian distribution. This also validates the hyperbolic distribution as a suitable distribution for construction quality management. [ABSTRACT FROM AUTHOR]

A new noise reduction algorithm is presented for signals displaying repeated patterns or multiple trials. Each pattern is stored in a matrix, forming a set of events, which is termed multievent signal. Each event is considered as an affine transform of a basic template signal that allows for time scaling and shifting. Wavelet transforms, decimated and undecimated, are applied to each event. Noise reduction on the set of coefficients of the transformed events is applied using either wavelet denoising or principal component analysis (PCA) noise reduction methodologies. The method does not require any manual selection of coefficients. Nonstationary multievent synthetic signals are employed to demonstrate the performance of the method using normalized mean square error against classical wavelet and PCA based algorithms. The new method shows a significant improvement in low SNRs (typically <0 dB). On the experimental side, evoked potentials in a visual oddball paradigm are used. The reduced-noise visual oddball event-related potentials reveal gradual changes in morphology from trial to trial (especially for N1-P2 and N2-P3 waves at F z), which can be hypothetically linked to attention or decision processes. The new noise reduction method is, thus, shown to be particularly suited for recovering single-event features in non-stationary low SNR multievent contexts. [ABSTRACT FROM AUTHOR]

This paper studies high-order wavelets of the first-order hyperbolic, Choi–Williams (CW) and nth-order hyperbolic kernels for analyses of digital time series, by using their second- and higher-order derivatives. For time-domain investigations, normalisation constants of the second-, fourth-, sixth-, eighth- and tenth-order hyperbolic and CW wavelets are numerically given. For frequency-domain investigations, wavelet parameters including band-peak frequencies, minimum numbers of sampling points, scale limits, scale resolutions and total number of scales are explicitly given and numerically estimated for the fourth-order hyperbolic and CW wavelets. Parameter comparisons among the Morlet wavelet, hyperbolic and CW second- and fourth-order wavelets are also given. Detection of periodicity and chaos in the Duffing oscillator is discussed. [Copyright &y& Elsevier]

Recycled aggregate (RA) has been used in various construction applications around the world mainly as sub-grade, roadwork and unbound materials, but not in higher-grade applications. The major barrier encountered is the variation of quality within RA, which causes lower strength, and poorer quality. This work studies the relationships among six parameters describing the characteristics of RA: (i) particle size distribution, (ii) particle density, (iii) porosity and absorption, (iv) particle shape, (v) strength and toughness, and (vi) chemical composition. Samples of RA from 10 demolition sites were obtained with service life ranging from 10 to 40 years. One additional set of samples was specifically collected from the Tuen Mun Area 38 Recycling Plant. The characteristics of these eleven sets of samples were then compared with normal aggregate samples. A Vandermonde matrix for interpolation polynomial coefficient estimation is used to give detailed mathematical relationships among pairs of samples, which can be used to work out redundant tests. Different orders of interpolation polynomials are used for comparison, hence the best-fit equations with the lowest fitting errors from different orders of polynomials can be found. Fitting error distributions are then studied by using spectral methods such as power spectra and bispectra. From that, the best equations for result estimations can be obtained. This study reveals that there is strong correlation among test parameters, and by measuring two of them: either “particle density” or “porosity and absorption” or “particle shape” or “strength and toughness”, and “chemical content”, it is sufficient to study RA. [Copyright &y& Elsevier]

Abstract: This paper theoretically derives an angle-of-arrival (AoA) probability density function in multi-path mobile environment where the scatterer distribution obeys a hyperbolic sech function. Using simulations, comparisons are made between the Gaussian distribution and the hyperbolic sech distribution for different distance from the base station (BS), user equipment (UE) and UE''s effective radius. [Copyright &y& Elsevier]

Abstract: This correspondence gives insight into properties of Wigner–Ville time–frequency power spectral analysis and also suggests better time–frequency power spectral tools to study cracks in rotors. Simulation results show that Choi–Williams and hyperbolic distributions can be effectively used for crack detection in rotors. [Copyright &y& Elsevier]

This article reports early results on digital implementation of first- and nth-order hyperbolic wavelets whose important parameters are explicitly expressed and numerically estimated. The first-order hyperbolic, Morlet and Choi–Williams wavelets are compared in detail by numerically calculating their band-peak frequencies, minimum numbers of sampling points, scale resolutions, and maximum numbers of scales. One of the main aims is to show that there exists a strong link among time–frequency kernels and wavelets. This relationship helps to expand and link time–frequency and wavelet approaches to signal analysis. One example of using the hyperbolic wavelet for speech recognition is also given. [ABSTRACT FROM AUTHOR]

Occupant behaviour (OB) is impacted by several interdisciplinary factors: environmental, psychosocial, cultural and economic. One of these impacting factors is the climate. In this study, the patterns of OB interactions with heating, cooling, lighting, equipment, windows and shading collected in questionnaire surveys were used as input data in the simulation models of two university buildings. The buildings, a green-rated and a non-rated one, are in Western Sydney University in Sydney, Australia. Then, the models were simulated in eight different climate zones in Australia. Therefore, this research aimed to understand how different climate zones may impact the energy related to OB and compare this impact between a green-rated building and a building without any rating. The results showed that there is no correlation between climate and OB and the levels of discomfort are related to the cooling season. The green building is less subjected to external changes, indicating that in buildings with automatic and properly controlled centralised management systems, the impacts related to the misuse of energy due to OB would be almost irrelevant. The results of this study should not be extended to other occupant behavioural patterns or situations. The results should be confined within the present research and context. [ABSTRACT FROM AUTHOR]