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Estuaries on wave-dominated coasts generally comprise three sedimentary environments: fluvial sands and gravels derived from the catchment; marine sands characteristic of the beaches and nearshore; and silts and clays that accumulate in the sheltered central basin. Estuarine transition to deltaic form occurs when geomorphological maturity is achieved during coastal evolution. Sedimentary plains become infilled and a narrow channel connects the catchment and facilitates the transport of fluvial sediments to the coast. Here, we present modern sedimentary data that supports the idea that the wave-dominated Shoalhaven system in southeastern Australia has transitioned from an estuary to delta, transporting fluvial sediments to the modern adjacent beach and contributing to coastal progradation. A total of 141 bed channel and swash zone samples were collected from the estuarine channel of the Shoalhaven River and the adjacent Comerong Island and Seven Mile Beach, respectively. Surficial sediments were subject to grain size analysis, whereas random quartz grains from selected samples were used to indicate a qualitative degree of weathering using a scan electron microscopy (SEM). Additionally, selected samples were examined for mineralogical composition using x-ray diffraction (XRD) to provide understanding of sediment transport and provenance. The dataset, one of the most comprehensive modern sedimentary coastal records in Australia, can be used to understand the sediment dynamics and support a diverse range of coastal management decisions. The experiment design and analyses also serve as a model that can be replicated elsewhere to better understand fluvial delivery of sediments to the coast. The dataset and analyses presented here support the research article entitled “Evolution from estuary to delta: alluvial plain morphology and sedimentary characteristics of the Shoalhaven River mouth, southeastern Australia” [1], to which readers should refer to for interpretation.

Until recently no universal agreement as to a philosophical or scientific methodological framework has been proposed to guide the study of fluvial geomorphology. An understanding of river form and process requires an understanding of the principles that govern the behaviour and evolution of alluvial rivers at the most fundamental level. To date, the investigations of such principles have followed four approaches: develop qualitative unifying theories that are usually untested; collect and examine data visually and statistically to define semi-quantitative relationships among variables; apply Newtonian theoretical and empirical mechanics in a reductionist manner; resolve the primary flow equations theoretically by assuming maximum or minimum outputs. Here we recommend not a fifth but an overarching philosophy to embrace all four: clarifying and formalising an understanding of the evolution of river channels and iterative directional changes in the context of least action principle (LAP), the theoretical basis of variational mechanics. LAP is exemplified in rivers in the form of maximum flow efficiency (MFE). A sophisticated understanding of evolution in its broadest sense is essential to understand how rivers adjust towards an optimum state rather than towards some other. Because rivers, as dynamic contemporary systems, flow in valleys that are commonly historical landforms and often tectonically determined, we propose that most of the world's alluvial rivers are over-powered for the work they must do. To remain stable they commonly evolve to expend surplus energy via a variety of dynamic equilibrium forms that will further adjust, where possible, to maximise their stability as much less common MFE forms in stationary equilibrium. This paper: 1. Shows that the theory of evolution is derived from, and applicable to, both the physical and biological sciences; 2. Focusses the development of theory in geomorphology on the development of equilibrium theory; 3. Proposes th

Until recently no universal agreement as to a philosophical or scientific methodological framework has been proposed to guide the study of fluvial geomorphology. An understanding of river form and process requires an understanding of the principles that govern the behaviour and evolution of alluvial rivers at the most fundamental level. To date, the investigations of such principles have followed four approaches: develop qualitative unifying theories that are usually untested; collect and examine data visually and statistically to define semi-quantitative relationships among variables; apply Newtonian theoretical and empirical mechanics in a reductionist manner; resolve the primary flow equations theoretically by assuming maximum or minimum outputs. Here we recommend not a fifth but an overarching philosophy to embrace all four: clarifying and formalising an understanding of the evolution of river channels and iterative directional changes in the context of least action principle (LAP), the theoretical basis of variational mechanics. LAP is exemplified in rivers in the form of maximum flow efficiency (MFE). A sophisticated understanding of evolution in its broadest sense is essential to understand how rivers adjust towards an optimum state rather than towards some other. Because rivers, as dynamic contemporary systems, flow in valleys that are commonly historical landforms and often tectonically determined, we propose that most of the world's alluvial rivers are over-powered for the work they must do. To remain stable they commonly evolve to expend surplus energy via a variety of dynamic equilibrium forms that will further adjust, where possible, to maximise their stability as much less common MFE forms in stationary equilibrium. This paper: 1. Shows that the theory of evolution is derived from, and applicable to, both the physical and biological sciences; 2. Focusses the development of theory in geomorphology on the development of equilibrium theory; 3. Proposes th

Until recently no universal agreement as to a philosophical or scientific methodological framework has been proposed to guide the study of fluvial geomorphology. An understanding of river form and process requires an understanding of the principles that govern the behaviour and evolution of alluvial rivers at the most fundamental level. To date, the investigations of such principles have followed four approaches: develop qualitative unifying theories that are usually untested; collect and examine data visually and statistically to define semi-quantitative relationships among variables; apply Newtonian theoretical and empirical mechanics in a reductionist manner; resolve the primary flow equations theoretically by assuming maximum or minimum outputs. Here we recommend not a fifth but an overarching philosophy to embrace all four: clarifying and formalising an understanding of the evolution of river channels and iterative directional changes in the context of least action principle (LAP), the theoretical basis of variational mechanics. LAP is exemplified in rivers in the form of maximum flow efficiency (MFE). A sophisticated understanding of evolution in its broadest sense is essential to understand how rivers adjust towards an optimum state rather than towards some other. Because rivers, as dynamic contemporary systems, flow in valleys that are commonly historical landforms and often tectonically determined, we propose that most of the world's alluvial rivers are over-powered for the work they must do. To remain stable they commonly evolve to expend surplus energy via a variety of dynamic equilibrium forms that will further adjust, where possible, to maximise their stability as much less common MFE forms in stationary equilibrium. This paper: 1. Shows that the theory of evolution is derived from, and applicable to, both the physical and biological sciences; 2. Focusses the development of theory in geomorphology on the development of equilibrium theory; 3. Proposes th

This paper presents the experimental investigation of the characterization of the narrowband on-body radio propagation channel at 2.45 GHz. Wearable planar textile monopole antennas (TM) were used in this measurement campaign. The measurements were conducted in the RF-shielded room environment, considering eight on-body radio links. A statistical analysis was conducted on the spectral parameters of the channel to enable the prediction and modeling of dynamic on-body radio propagation characteristics. The empirical data were fitted to several well-known statistical models to determine the model that provided the best fit for the data. The results showed that the path loss exponent was consistent with the results of previous studies. The results also demonstrated that lognormal distribution was found to be the best fit for path loss in dynamic on-body radio propagation channel.

This paper presents the experimental investigation of the characterization of the narrowband on-body radio propagation channel at 2.45 GHz. Wearable planar textile monopole antennas (TM) were used in this measurement campaign. The measurements were conducted in the RF-shielded room environment, considering eight on-body radio links. A statistical analysis was conducted on the spectral parameters of the channel to enable the prediction and modeling of dynamic on-body radio propagation characteristics. The empirical data were fitted to several well-known statistical models to determine the model that provided the best fit for the data. The results showed that the path loss exponent was consistent with the results of previous studies. The results also demonstrated that lognormal distribution was found to be the best fit for path loss in dynamic on-body radio propagation channel.

This paper presents the experimental investigation of the characterization of the narrowband on-body radio propagation channel at 2.45 GHz. Wearable planar textile monopole antennas (TM) were used in this measurement campaign. The measurements were conducted in the RF-shielded room environment, considering eight on-body radio links. A statistical analysis was conducted on the spectral parameters of the channel to enable the prediction and modeling of dynamic on-body radio propagation characteristics. The empirical data were fitted to several well-known statistical models to determine the model that provided the best fit for the data. The results showed that the path loss exponent was consistent with the results of previous studies. The results also demonstrated that lognormal distribution was found to be the best fit for path loss in dynamic on-body radio propagation channel.

This paper presents the experimental investigation of the characterization of the narrowband on-body radio propagation channel at 2.45 GHz. Wearable planar textile monopole antennas (TM) were used in this measurement campaign. The measurements were conducted in the RF-shielded room environment, considering eight on-body radio links. A statistical analysis was conducted on the spectral parameters of the channel to enable the prediction and modeling of dynamic on-body radio propagation characteristics. The empirical data were fitted to several well-known statistical models to determine the model that provided the best fit for the data. The results showed that the path loss exponent was consistent with the results of previous studies. The results also demonstrated that lognormal distribution was found to be the best fit for path loss in dynamic on-body radio propagation channel.

This letter deals with message passing receiver design for joint channel estimation and decoding in MIMO-OFDM with unknown noise variance. The conventional factor graph representation for the system involves observation factors, which are functions of a number of variables in the form of multiplication and summation. In this work, by introducing some auxiliary variables, we further break each of the observation factors into several factors, which enables the use of hybrid mean field (MF), belief propagation (BP), and expectation propagation (EP) message passing to tackle the observation factors. It turns out that our approach is much more efficient than the existing approaches, leading to remarkable performance improvement as shown by simulation results.

This letter deals with message passing receiver design for joint channel estimation and decoding in MIMO-OFDM with unknown noise variance. The conventional factor graph representation for the system involves observation factors, which are functions of a number of variables in the form of multiplication and summation. In this work, by introducing some auxiliary variables, we further break each of the observation factors into several factors, which enables the use of hybrid mean field (MF), belief propagation (BP), and expectation propagation (EP) message passing to tackle the observation factors. It turns out that our approach is much more efficient than the existing approaches, leading to remarkable performance improvement as shown by simulation results.

This paper considers pilot-based (or training-based) channel matrix estimation in downlink multiuser multiple input multiple output (MIMO) wireless communication systems under Rician fading. The Bayesian approach is used to analyse and derive closed-form mathematical expressions for the minimum mean square estimator (MMSE) and the mean square error (MSE) in estimating the channel state information (CSI) where the long-term channel statistics are known a priori. It is shown how the pilot matrix can be designed to maximize the estimation performance. MATLAB simulation examples are used to evaluate the performance of the MMSE channel estimator for different training sequences and system statistics and to show how both the optimal length of the training sequence (number of columns of the pilot matrix) and the channel estimation error decreases with the spatial correlation

Data sharing and searching are important functionalities in cloud storage. In this paper, we show how to securely and flexibly search and share cloud data among a group of users without a group manager. We formalize a novel cryptosystem: secure channel free searchable encryption in a peer-to-peer group, which features with the secure cloud data sharing and searching for group members in an identity-based setting. Our scheme allows group members to join or leave the group dynamically. We present two schemes: basic scheme and enhanced scheme. We formally prove that our basic scheme achieves consistency and indistinguishability against the chosen keyword and ciphertext attack and the outsider's keyword guessing attack, respectively. An enhanced scheme is also proposed to achieve forward secrecy, which allows to revoke user search right over the former shared data.

Data sharing and searching are important functionalities in cloud storage. In this paper, we show how to securely and flexibly search and share cloud data among a group of users without a group manager. We formalize a novel cryptosystem: secure channel free searchable encryption in a peer-to-peer group, which features with the secure cloud data sharing and searching for group members in an identity-based setting. Our scheme allows group members to join or leave the group dynamically. We present two schemes: basic scheme and enhanced scheme. We formally prove that our basic scheme achieves consistency and indistinguishability against the chosen keyword and ciphertext attack and the outsider's keyword guessing attack, respectively. An enhanced scheme is also proposed to achieve forward secrecy, which allows to revoke user search right over the former shared data.

Wireless Body Area Network (WBAN) has been considered as a revolutionary technology to address current healthcare needs. However, before the extensive deployment of WBAN, one main challenge to be met is how to balance the trade-off between data transmission rate and energy efficiency. In this paper, we utilize WBAN's spatial correlation characteristics during movement and propose an efficient cross-layer scheme, named A3NC, which combines analog network coding (ANC) and MAC layer channel allocation. Our simulation results show that the A3NC scheme achieves significant improvement in upload throughput and energy efficiency compared to the conventional approaches. Meanwhile, our scheme also maintains a better balance between correlated sensors' upload throughput.

In this paper, we address the design of message-passing receiver for massive multiple-input multiple-output orthogonal frequency division multiplex (MIMO-OFDM) systems. With the aid of the central limit argument and Taylor-series approximation, a computationally efficient receiver that performs joint channel estimation and decoding is devised by the framework of expectation propagation. In particular, the local belief defined at the channel transition function is expanded up to the second order with Wirtinger calculus, to transform the messages sent by the channel transition function to a tractable form. As a result, the channel impulse response between each pair of antennas is estimated by Gaussian message passing. In addition, a variational expectation-maximization-based method is derived to learn the channel power-delay profiles. The proposed scheme is assessed in 3D massive MIMO-OFDM systems with spatially correlated channels, and the empirical results corroborate its superiority in terms of performance and complexity.

An innovative wave-based time-domain passivity approach applied to a four-channel nonlinear teleoperation system is proposed. The primary objective of this approach is to enhance system transparency while maintaining stability in the presence of random time delays. The system stability for different scenarios of human and environment condition is analyzed. The method is validated through experimental work based on a 3-DOF bilateral teleoperation system. The experimental results show that the proposed control algorithm can robustly guarantee the system stability, and simultaneously provide better performance than methods developed in previous work.

This paper reports an investigation into the effect of carbon dioxide (CO2) gas on various ultra wideband channel coefficients. Measurements were conducted using apparatus consisting of a rubberized tube (6 mm diameter) connected to a source of CO2 or nitrogen (N2). For support, the rubberized tube was wrapped twice around a PVC pipe (160 mm diameter). The rubberized tube was flushed with 100% CO2 several times before being sealed in the tube at atmospheric pressure. In between measurement trials, removal of CO2 was achieved by flushing with pure nitrogen. A Vector Network Analyzer (VNA) using two identical directional antennas, with the wrapped section of tubing placed in-between, measured the channel coefficients over ultra wideband frequency spans of (0.3-8) GHz and (1-2) GHz. Significant magnitude differences between the baseline condition and that of CO2 were observed. We found the same signature of difference curves over the same frequency spans for different measurements. Difference in shape in the frequency band of (1-2) GHz is the same as that of the measured difference over 1-2 GHz in entire frequency band of 300 MHz to 8 GHz for the measured channel coefficients.

In this work, a novel microfluidic platform for tunable particle focusing in a straight channel with symmetric semicircle obstacle arrays using electrophoresis (EP)-modified inertial effects was presented. By exerting an EP force on the charged microparticles, a relative velocity gap between microspheres and fluid in a straight channel with symmetric semicircle obstacle arrays was implemented. The relative velocity and fluid shear will induce shear-slip lift force (Saffman lift force) perpendicular to the mainstream direction. Therefore, the focusing pattern can be altered using the electrophoresis-induced Saffman force. The effects of electric field direction, flow rate, electric field magnitude, and particle size were also studied. This demonstrates the possibility of adjusting the particle inertial focusing pattern in a straight channel with with symmetric semicircle obstacle arrays using electrophoresis. Manipulation of the lateral migration of focusing streaks increases controllability in applications such as blood cell filtration and the separation of cells by size.

Recording systems to acquire electroencephalogram (EEG) data are traditionally lab-based. However, there are shortcomings to this method, and the ease of use and portability of emerging wireless EEG technologies offer a promising alternative. A previous validity study demonstrated data derived from a single-channel, wireless system (NeuroSky ThinkGear, San Jose, California) is comparable to EEG recorded from conventional lab-based equipment. The current study evaluated the reliability of this portable system using test-retest and reliable change analyses. Relative power (RP) of delta, theta, alpha, and beta frequency bands was derived from EEG data obtained from a single electrode over FP1 in 19 healthy youth (10-17 years old), 21 healthy adults (18-28 years old), and 19 healthy older adults (55-79 years old), during eyes-open, eyes-closed, auditory oddball, and visual n-back conditions. Intra-class correlations (ICCs) and Coefficients of Repeatability (CRs) were calculated from RP data re-collected one-day, one-week, and one-month later. Participants' levels of mood and attention were consistent across sessions. Eyes-closed resting EEG measurements using the portable device were reproducible (ICCs 0.76-0.85) at short and longer retest intervals in all three participant age groups. While still of at least fair reliability (ICCs 0.57-0.85), EEG obtained during eyes-open paradigms was less stable, and any change observed over time during these testing conditions can be interpreted utilizing the CR values provided. Combined with existing validity data, these findings encourage application of the portable EEG system for the study of brain function.

Signal estimation in MIMO communications typically suffers from performance degradations due to imperfect channel state information (CSI). Traditional robustification schemes rely on assumptions about the model uncertainty and may result in conservative performance. We introduce a rank-reduction approach that enhances the performance in training-based applications. A sequence of reduced-rank channel estimates are established from the training data. Multiple, distinct estimates of the transmit signal are then generated by applying standard detectors to each of those models, among which the 'best' is chosen by data-driven methods. This way significant performance improvements can be achieved, especially for ill-conditioned channels.

This paper analyzes the measurement of ultra wideband (UWB) noise channels in different indoor environments. All measurements are done using a vector network analyzer (VNA) which allows us to measure the noise channel transfer functions. We find that the noise power of the system is decreased by increasing the intermediate frequency (IF) bandwidth which leads to an increase in time taken to perform measurements of the channels. The environmental noise power been measured and find that it decreased when enclosed in a Faraday cage (steel shed), within an intense multipath measurement environment. Also, the Environmental noise decreases slightly by using the LPDA antenna compared to using the Teardrop and Horn antennas. Our results show that the Horn antenna is less suitable for UWB channel measurements compared to the LPDA directional antennas because of lower S11 (Return Loss) values. While for omnidirectional antennas, the Teardrop antenna is much more suitable than the monocone antennas for UWB measurements (due to lower S11 values) and decreases the Environmental noise power. As secondary application, we show how a frequency detection device can be used to re-adjust a maladjusted frequency selection on a remote controller for a garage door, in presence of environmental noise power.

This paper proposes a novel extension on Non-negative Matrix Factorization (NMF) scheme for the separation of single channel speech mixtures, where we impose a post-sparse model on the original weight matrix derived from a previously proposed coherence-constrained NMF model. The approach considers both the modeling ability of NMF basis functions for each source as well as the ability of these basis functions to achieve accurate separation performance. Compared with latest associated NMF models for source separation, the results of our model indicate promising advantages, in terms of both objective source separation measures and Perceptual Evaluation of Speech Quality (PESQ) evaluations.

In this paper, 3D particle focusing in a straight channel with asymmetrical expansion-contraction cavity arrays (ECCA channel) is achieved by exploiting the dean-flow-coupled elasto-inertial effects. First, the mechanism of particle focusing in both Newtonian and non-Newtonian fluids was introduced. Then particle focusing was demonstrated experimentally in this channel with Newtonian and non- Newtonian fluids using three different sized particles (3.2 lm, 4.8 lm, and 13 lm), respectively. Also, the effects of dean flow (or secondary flow) induced by expansion- contraction cavity arrays were highlighted by comparing the particle distributions in a single straight rectangular channel with that in the ECCA channel. Finally, the influences of flow rates and distances from the inlet on focusing performance in the ECCA channel were studied. The results show that in the ECCA channel particles are focused on the cavity side in Newtonian fluid due to the synthesis effects of inertial and dean-drag force, whereas the particles are focused on the opposite cavity side in non-Newtonian fluid due to the addition of viscoelastic force. Compared with the focusing performance in Newtonian fluid, the particles are more easily and better focused in non-Newtonian fluid. Besides, the Dean flow in visco-elastic fluid in the ECCA channel improves the particle focusing performance compared with that in a straight channel. A further advantage is threedimensional (3D) particle focusing that in non-Newtonian fluid is realized according to the lateral side view of the channel while only two-dimensional (2D) particle focusing can be achieved in Newtonian fluid. Conclusively, this novel Dean-flowcoupled elasto-inertial microfluidic device could offer a continuous, sheathless, and high throughput (>10 000 s-1) 3D focusing performance, which may be valuable in various applications from high speed flow cytometry to cell counting, sorting, and analysis.

This paper proposes a new approach to joint Doppler spread and channel estimation over Rayleigh fading channels through an iterative process between a Doppler spread estimator and a channel estimator. Our proposed Doppler spread estimator is based on the autocorrelation function (ACF) of the estimated channel coefficients, where we devise an ACF lag selection mechanism to maximize the performance of the Doppler spread estimation. We use a Forney-style factor graph to represent the fading channel with a first order autoregressive (AR(1)) model and implement a Gaussian message passing based channel estimator for Doppler spread estimation, where the AR(1) model coefficients are optimized. Compared to the existing joint Doppler spread and channel estimation approaches, the proposed approach achieves similar or better performance with lower complexity.

Objectives To investigate how gamblers interact with, and respond to, downstream social marketing campaigns that focus on the risks and harms of problem gambling and/or encourage help seeking. Methods Qualitative study of 100 gamblers with a range of gambling behaviours (from non-problem to problem gambling). We used a Social Constructivist approach. Our constant comparative method of data interpretation focused on how participants' experiences and interactions with gambling influenced their opinions towards, and interactions with social marketing campaigns. Results Three key themes emerged from the narratives. (i) Participants felt that campaigns were heavily skewed towards encouraging individuals to take personal responsibility for their gambling behaviours or were targeted towards those with severe gambling problems. (ii) Participants described the difficulty for campaigns to achieve 'cut through' because of the overwhelming volume of positive messages about the benefits of gambling that were given by the gambling industry. (iii) Some participants described that dominant discourses about personal responsibility prevented them from seeking help and reinforced perceptions of stigma. Conclusions and implications Social marketing campaigns have an important role to play in the prevention of gambling risk behaviours and the promotion of help seeking. Social marketers should explore how to more effectively target campaigns to different audience segments, understand the role of environmental factors in undermining the uptake of social marketing strategies and anticipate the potential unforeseen consequences of social marketing strategies.

This communication reports the structural and functional characterization of urotoxin, the first K+ channel toxin isolated from the venom of the Australian scorpion Urodacus yaschenkoi. It is a basic peptide consisting of 37 amino acids with an amidated C-terminal residue. Urotoxin contains eight cysteines forming four disulfide bridges with sequence similarities resembling the α-potassium channel toxin 6 (α-KTx-6) subfamily of peptides; it was assigned the systematic number of α-KTx-6.21. Urotoxin is a potent blocker of human voltage-gated potassium channel (Kv)1.2 channels, with an IC50 of 160 pM, whereas its affinity for other channels tested was in the nanomolar range (hKv1.1, IC50 = 253 nM; hKv1.3, IC50 = 91 nM; and hKCa3.1, IC50 = 70 nM). The toxin had no effect on hKv1.4, hKv1.5, human ether-à-go-go-related gene type 1 (hERG1), or human ether-à-go-go-like (hELK2) channels. Multiple sequence alignments from the venom gland transcriptome showed the existence of four other new peptides similar to urotoxin. Computer modeling of urotoxin's three-dimensional structure suggests the presence of the α/β-scaffold characteristic of other scorpion toxins, although very likely forming an uncommon disulfide pairing pattern. Using molecular dynamics, a model for the binding of this peptide to human Kv1.2 and hKv1.1 channels is presented, along with the binding of an in silico mutant urotoxin (Lys25Ala) to both channels. Urotoxin enriches our knowledge of K+ channel toxins and, due to its high affinity for hKv1.2 channels, it may be a good candidate for the development of pharmacologic tools to study the physiologic functions of K+ channels or related channelopathies and for restoring axonal conduction in demyelinated axons.

Equal channel angular pressing (ECAP) has attracted a lot of interest due to its ability for fabrication of bulk ultrafine-grained materials. With the development of computer skills, the computer-aided methods become very important and useful in understanding the deformation mechanism of ECAP. In this study, the influence of mesh size during finite element simulations of ECAP has been examined based on the plane strain condition assumption. Four different meshes have been compared and these results indicate that Mesh 600 and Mesh 2400 fail to capture the deformation features of ECAP accurately. Large corner gaps develop in these two cases and the simulated strains are smaller than the analytical calculations. Similar results have been obtained between Mesh 6369 and Mesh 12000 and the predicted features of plastic deformation and texture evolution are consistent with the experimental results.

Stability and transparency are two critical indices of bilateral teleoperation systems. The wave variable method is a conservative approach to robustly guarantee system passivity under arbitrary constant time delays. However, the wave-variable-based reflection is an intrinsic problem in this method because it can significantly degrade system transparency and disorient the operator's perception of the remote environment. In order to enhance both the transparency and the stability of bilateral teleoperation systems in the presence of large time delays, a new four-channel (4-CH) architecture is proposed which applies two modified wave-transformation controllers to reduce wave-based reflections. Transparency and stability of the proposed system are analyzed and the improvement in these when using this method is measured experimentally. Results clearly demonstrate that the proposed method can produce high transparency and stability even in the presence of large time delays. Copyright Cambridge University Press 2014.

This paper considers the coded OFDM system and instead of discarding the cyclic prefix (CP) at the receiver, we utilize the CP observation for joint detection, decoding and channel estimation. In particular, detection and decoding are performed iteratively between an equalizer and a soft-input soft-output (SISO) decoder based on the turbo principle, and the expectation-maximization (EM) algorithm is employed in the equalizer for joint detection and channel estimation via message passing. Models for the CP observation, non-CP observation and the time correlation of the time-varying channel are presented in Forney-style factor graphs (FFGs), and a scheduling scheme is proposed to pass messages between the graphs. Simulation results show that with unknown channel impulse response (CIR), the performance of the proposed algorithm approaches the case where CIR is perfectly known and through proper exploitation of the CP, the proposed algorithm outperforms the conventional algorithm (i.e. CP is discarded) with known CIR, as well as the alternative algorithm in the literature (where CP is exploited) with unknown CIR.

Stability and transparency are two critical indices of bilateral teleoperation systems. The wave variable method is a conservative approach to robustly guarantee system passivity under arbitrary constant time delays. However, the wave-variable-based reflection is an intrinsic problem in this method because it can significantly degrade system transparency and disorient the operator's perception of the remote environment. In order to enhance both the transparency and the stability of bilateral teleoperation systems in the presence of large time delays, a new four-channel (4-CH) architecture is proposed which applies two modified wave-transformation controllers to reduce wave-based reflections. Transparency and stability of the proposed system are analyzed and the improvement in these when using this method is measured experimentally. Results clearly demonstrate that the proposed method can produce high transparency and stability even in the presence of large time delays. Copyright Cambridge University Press 2014.

This paper considers the coded OFDM system and instead of discarding the cyclic prefix (CP) at the receiver, we utilize the CP observation for joint detection, decoding and channel estimation. In particular, detection and decoding are performed iteratively between an equalizer and a soft-input soft-output (SISO) decoder based on the turbo principle, and the expectation-maximization (EM) algorithm is employed in the equalizer for joint detection and channel estimation via message passing. Models for the CP observation, non-CP observation and the time correlation of the time-varying channel are presented in Forney-style factor graphs (FFGs), and a scheduling scheme is proposed to pass messages between the graphs. Simulation results show that with unknown channel impulse response (CIR), the performance of the proposed algorithm approaches the case where CIR is perfectly known and through proper exploitation of the CP, the proposed algorithm outperforms the conventional algorithm (i.e. CP is discarded) with known CIR, as well as the alternative algorithm in the literature (where CP is exploited) with unknown CIR.

This paper considers the coded OFDM system and instead of discarding the cyclic prefix (CP) at the receiver, we utilize the CP observation for joint detection, decoding and channel estimation. In particular, detection and decoding are performed iteratively between an equalizer and a soft-input soft-output (SISO) decoder based on the turbo principle, and the expectation-maximization (EM) algorithm is employed in the equalizer for joint detection and channel estimation via message passing. Models for the CP observation, non-CP observation and the time correlation of the time-varying channel are presented in Forney-style factor graphs (FFGs), and a scheduling scheme is proposed to pass messages between the graphs. Simulation results show that with unknown channel impulse response (CIR), the performance of the proposed algorithm approaches the case where CIR is perfectly known and through proper exploitation of the CP, the proposed algorithm outperforms the conventional algorithm (i.e. CP is discarded) with known CIR, as well as the alternative algorithm in the literature (where CP is exploited) with unknown CIR.

Stability and transparency are two critical indices of bilateral teleoperation systems. The wave variable method is a conservative approach to robustly guarantee system passivity under arbitrary constant time delays. However, the wave-variable-based reflection is an intrinsic problem in this method because it can significantly degrade system transparency and disorient the operator's perception of the remote environment. In order to enhance both the transparency and the stability of bilateral teleoperation systems in the presence of large time delays, a new four-channel (4-CH) architecture is proposed which applies two modified wave-transformation controllers to reduce wave-based reflections. Transparency and stability of the proposed system are analyzed and the improvement in these when using this method is measured experimentally. Results clearly demonstrate that the proposed method can produce high transparency and stability even in the presence of large time delays. Copyright Cambridge University Press 2014.

Stability and transparency are two critical indices of bilateral teleoperation systems. The wave variable method is a conservative approach to robustly guarantee system passivity under arbitrary constant time delays. However, the wave-variable-based reflection is an intrinsic problem in this method because it can significantly degrade system transparency and disorient the operator's perception of the remote environment. In order to enhance both the transparency and the stability of bilateral teleoperation systems in the presence of large time delays, a new four-channel (4-CH) architecture is proposed which applies two modified wave-transformation controllers to reduce wave-based reflections. Transparency and stability of the proposed system are analyzed and the improvement in these when using this method is measured experimentally. Results clearly demonstrate that the proposed method can produce high transparency and stability even in the presence of large time delays. Copyright Cambridge University Press 2014.

This paper considers the coded OFDM system and instead of discarding the cyclic prefix (CP) at the receiver, we utilize the CP observation for joint detection, decoding and channel estimation. In particular, detection and decoding are performed iteratively between an equalizer and a soft-input soft-output (SISO) decoder based on the turbo principle, and the expectation-maximization (EM) algorithm is employed in the equalizer for joint detection and channel estimation via message passing. Models for the CP observation, non-CP observation and the time correlation of the time-varying channel are presented in Forney-style factor graphs (FFGs), and a scheduling scheme is proposed to pass messages between the graphs. Simulation results show that with unknown channel impulse response (CIR), the performance of the proposed algorithm approaches the case where CIR is perfectly known and through proper exploitation of the CP, the proposed algorithm outperforms the conventional algorithm (i.e. CP is discarded) with known CIR, as well as the alternative algorithm in the literature (where CP is exploited) with unknown CIR.

This is a simulation study of weight-based and precedence-based clustering paradigms in VANETs under an experimentally-derived channel model. The study reveals that CH election schemes accounting for driver intention form more stable and long-lived clusters. The results also show that ignoring elements of the VANET channel (such as vehicular shadowing) results in an unreliable comparative analysis of protocol performance.

A Laser Doppler Anemometer was used to measure the mean flow and turbulence in fluid experiments despite it having a problem with the mean velocity bias when a LDA is used to measure turbulent flows. It is generally considered that given a sufficiently large sample size, LDA will produce measurements free of bias, even with high turbulence intensity, but there is no relative experimental validation to demonstrate how the sample size affects the mean velocity bias. This paper first tries to find the reasonable sample size that ensures a mean velocity calculation free of bias. Furthermore, the effects of particle seeding concentration on the measurements of velocity were also considered. Throughout the experimental process the particle velocities were measured using a Dantec 2-D LDA system. To describe the effects of sample size and particle seeding concentration, this paper will also address the reasonable sample size and range of concentration in the design of water flow prior to any experimental application.

This paper presents an inertial microfluidic device with a simple serpentine micro-channel to continuously separate particles with high performance. Separation of micro/nano-particles has a variety of potential applications in biomedicine and industry. Among the existing separation technologies, a label-free technique without the use of antibody affinity, filter or centrifugation is highly desired to ensure minimal damage and alteration to the cells. Inertial microfluidics utilising hydrodynamic forces to separate particles is one of the most suitable label-free technologies with a high throughput. Our separation concept relies on size-based differential equilibrium positions of the particles perpendicular to the flow. Highly efficient separation is demonstrated with particles of different sizes. The results indicate that the proposed device has an integrative advantage to the existing microfluidic separation techniques, taking accounts of purity, efficiency, parallelizability, footprint, throughput and resolution. Our device is expected to be a good alternative to conventional separation methods for sample preparation and clinical diagnosis.

We propose a message-passing algorithm of joint channel estimation and decoding for OFDM systems, where expectation propagation is exploited to deal with channel estimation. Specially, the message updating is formulated into a recursive form. As a result, for system with K subcarriers and L channel taps, only O(K + L) messages need to be tracked, and meanwhile they can be efficiently calculated using FFT with complexity O(K|A| + K log2 K), where |A| denotes the constellation size. Numerical experiments show that our algorithm achieves BER performance within 0.5 dB of the knownchannel bound.

This paper considers the coded OFDM system and instead of discarding the cyclic prefix (CP) at the receiver, we utilize the CP observation for joint detection, decoding and channel estimation. In particular, detection and decoding are performed iteratively between an equalizer and a soft-input soft-output (SISO) decoder based on the turbo principle, and the expectation-maximization (EM) algorithm is employed in the equalizer for joint detection and channel estimation via message passing. Models for the CP observation, non-CP observation and the time correlation of the time-varying channel are presented in Forney-style factor graphs (FFGs), and a scheduling scheme is proposed to pass messages between the graphs. Simulation results show that with unknown channel impulse response (CIR), the performance of the proposed algorithm approaches the case where CIR is perfectly known and through proper exploitation of the CP, the proposed algorithm outperforms the conventional algorithm (i.e. CP is discarded) with known CIR, as well as the alternative algorithm in the literature (where CP is exploited) with unknown CIR.

Equal channel angular pressing (ECAP) has attracted a lot of interest due to its ability for fabrication of bulk ultrafine-grained materials. With the development of computer skills, the computer-aided methods become very important and useful in understanding the deformation mechanism of ECAP. In this study, the influence of mesh size during finite element simulations of ECAP has been examined based on the plane strain condition assumption. Four different meshes have been compared and these results indicate that Mesh 600 and Mesh 2400 fail to capture the deformation features of ECAP accurately. Large corner gaps develop in these two cases and the simulated strains are smaller than the analytical calculations. Similar results have been obtained between Mesh 6369 and Mesh 12000 and the predicted features of plastic deformation and texture evolution are consistent with the experimental results.

Over the lasts two decades equal channel angular pressing (ECAP) has been widely used to produce ultrafine grained microstructures with excellent mechanical properties in metallic materials. In this paper, a crystal plasticity finite element method (CPFEM) investigation has been carried out to examine the texture evolution and deformation heterogeneity of copper single crystals deformed by ECAP process. Two single crystals were simulated to examine the influence of initial crystallographic orientation. In the first crystal, the (111) slip plane and the [110] slip direction have been rotated by 20° in a clockwise direction around the transverse direction from the theoretical shear plane and theoretical shear direction of the ECAP die, respectively. By contrast in the second crystal, the (111) slip plane and the [110] slip direction were rotated 20° in a counter‐clockwise direction. The results of the simulation show that the initial crystallographic orientation has a great influence on the deformed geometry, formation of the corner gap, distribution of the plastic strain rate and texture evolution when copper single crystals are undergoing ECAP process. The crystallographic rotation patterns during deformation have been quantitatively estimated and the predicted textures are consistent with the experimental results in the literature.

Equal channel angular pressing (ECAP), or equal channel angular extrusion (ECAE), is a very promising severe plastic deformation technique for producing ultra-fine grained (UFG) materials. Up to now, many works have been contributed to understand the influence of die geometry, frictional condition and back-pressure during the ECAP process. Most of them only focused on a specific sample size, and very few investigations about the sample size effect have been reported. Therefore, the present investigation was designed specifically to provide systematical information on the influence of sample size on the deformation heterogeneity and texture development after ECAP. To the authors' knowledge, this is the first attempt to consider the sample dimension influence on the texture evolution of ECAP processed aluminum single crystals. Study has been successfully conducted using crystal plasticity finite element model for four different samples having widths between 2 mm and 40 mm. For each of sample, the simulated effective plastic strain is close to the theoretical value. The calculated shear strength and stress decreased slightly with the sample width, but show very little change at larger samples. Simulation results revealed similar deformation heterogeneity during the process as the reference. The predicted {1 1 1} pole figures and activity of slip systems indicate that the texture evolution is independent of the sample dimension. Simulation results are consistent with the experimental observations when the same initial crystallographic orientation and sample size have been used. The present work offers a good suggestion for the scaling up of the ECAP process for the industrial application from the views of both deformation pattern and evolution of texture. © 2013 Elsevier B.V. All rights reserved.

In order to improve the efficiency of grain refinement, a study on the modified process (called Non-equal channel angular pressing) from the conventional equal channel angular pressing has been conducted. The deformation behavior of aluminum alloy AA1050 deformed by the Non-equal channel angular pressing which has a smaller width in the exit channel than the entry channel was examined based on the finite element simulations. The results revealed that a smaller ratio of dE and dI (dE/dI) leads to a larger equivalent plastic strain. It is not only beneficial to enhance the plastic deformation but also very helpful to get rid of the development of dead zone in the outer corner of die by decreasing the exit channel width by comparing with the conventional process. © (2013) Trans Tech Publications, Switzerland.

This paper examines the accuracy of equations specified by the North American and Australasian steel structures codes for determining the net section tension capacity of a channel brace. It points out that there are three distinct factors affecting the net section efficiency of a cold-formed steel channel brace bolted at the web. These factors are the in-plane shear lag associated with stress concentration around a bolt hole that is also present in flat sheets, the out-of-plane shear lag that is also present in an I-section bolted at the flanges only, and the bending moment arising from the connection eccentricity with respect to the neutral axis. Each of the relevant factors is explicitly incorporated in the equation proposed in this paper for determining the net section tension capacity of a cold-formed steel channel brace bolted at the web. The proposed equation is demonstrated through laboratory tests on low ductility channel braces having practical aspect ratios that were bolted onto flexible plates to be more reliable than the code equations and those existing in the literature.

We report a simple, low-cost and novel method for constructing three-dimensional (3D) microelectrodes in microfluidic system by utilizing low melting point metal alloy. Three-dimensional electrodes have unique properties in application of cell lysis, electro-osmosis, electroporation and dielectrophoresis. The fabrication process involves conventional photolithography and sputtering techniques to fabricate planar electrodes, positioning bismuth (Bi) alloy microspheres at the sidewall of PDMS channel, plasma bonding and low temperature annealing to improve electrical connection between metal microspheres and planar electrodes. Compared to other fabrication methods for 3D electrodes, the presented one does not require rigorous experimental conditions, cumbersome processes and expensive equipments. Numerical analysis on electric field distribution with different electrode configurations was presented to verify the unique field distribution of arc-shaped electrodes. The application of 3D electrode configuration with high-conductive alloy microspheres was confirmed by particle manipulation based on dielectrophoresis. The proposed technique offers alternatives to construct 3D electrodes from 2D electrodes. More importantly, the simplicity of the fabrication process provides easy ways to fabricate electrodes fast with arc-shaped geometry at the sidewall of microchannel

This paper presents a technique for low bit rate compression of three-dimensional (3D) audio produced by multiple loudspeaker channels. The approach is based on the time-frequency analysis of the localization of spatial sound sources within the 3D space as rendered by a multi-channel audio signal (in this case 16 channels). This analysis results in the derivation of a stereo downmix signal representing the original 16 channels. Alternatively, a mono-downmix signal with side information representing the location of sound sources within the 3D spatial scene can also be derived. The resulting downmix signals are then compressed with a traditional audio coder, resulting in a representation of the 3D soundfield at bit rates comparable with existing stereo audio coders while maintaining the perceptual quality produced from separate encoding of each channel. © 2006-2012 IEEE.

This paper presents a technique for low bit rate compression of three-dimensional (3D) audio produced by multiple loudspeaker channels. The approach is based on the time-frequency analysis of the localization of spatial sound sources within the 3D space as rendered by a multi-channel audio signal (in this case 16 channels). This analysis results in the derivation of a stereo downmix signal representing the original 16 channels. Alternatively, a mono-downmix signal with side information representing the location of sound sources within the 3D spatial scene can also be derived. The resulting downmix signals are then compressed with a traditional audio coder, resulting in a representation of the 3D soundfield at bit rates comparable with existing stereo audio coders while maintaining the perceptual quality produced from separate encoding of each channel. © 2006-2012 IEEE.

This paper presents a technique for low bit rate compression of three-dimensional (3D) audio produced by multiple loudspeaker channels. The approach is based on the time-frequency analysis of the localization of spatial sound sources within the 3D space as rendered by a multi-channel audio signal (in this case 16 channels). This analysis results in the derivation of a stereo downmix signal representing the original 16 channels. Alternatively, a mono-downmix signal with side information representing the location of sound sources within the 3D spatial scene can also be derived. The resulting downmix signals are then compressed with a traditional audio coder, resulting in a representation of the 3D soundfield at bit rates comparable with existing stereo audio coders while maintaining the perceptual quality produced from separate encoding of each channel. © 2006-2012 IEEE.

A sudden drop in river base-level can trigger a knickpoint that propagates throughout the fluvial network causing a transient state in the landscape. Knickpoint retreat has been confirmed in large fluvial settings (drainage areas > 100 km2) and field data suggest that the same applies to the case of small bedrock river catchments (drainage areas < 100 km2). Nevertheless, knickpoint recession on resistant lithologies with structure that potentially affects the retreat rate needs to be confirmed with field-based data. Moreover, it remains unclear whether small bedrock rivers can absorb base-level fall via knickpoint retreat. Here we evaluate the response of small bedrock rivers to base-level fall on the isle of Jura in western Scotland (UK), where rivers incise into dipping quartzite. The mapping of raised beach deposits and strath terraces, and the analysis of stream long profiles, were used to identify knickpoints that had been triggered by base-level fall. Our results indicate that the distance of knickpoint retreat scales to the drainage area in a power law function irrespective of structural setting. On the other hand, local channel slope and basin size influence the vertical distribution of knickpoints. As well, at low drainage areas (~ 4 km2) rivers are unable to absorb the full amount of base-level fall and channel reach morphology downstream of the knickpoint tends towards convexity. The results obtained here confirm that knickpoint retreat is mostly controlled by stream discharge, as has been observed for other transient landscapes. Local controls, reflecting basin size and channel slope, have an effect on the vertical distribution of knickpoints; such controls are also related to the ability of rivers to absorb the base-level fall.