bluuebunny/crossref_metadata_2025 huggingface dataset:
Sites of persistence of Fusobacterium necrophorum and Dichelobacter nodosus: a paradigm shift in understanding the epidemiology of footrot in sheep
Authors: Clifton Rachel , Giebel Katharina , Liu Nicola L. B. H. , Purdy Kevin J. , Green Laura E.
Published: October 2019

Sites of persistence of bacterial pathogens contribute to disease dynamics of bacterial diseases. Footrot is a globally important bacterial disease that reduces health and productivity of sheep. It is caused byDichelobacter nodosus, a pathogen apparently highly specialised for feet, whileFusobacterium necrophorum, a secondary pathogen in footrot is reportedly ubiquitous on pasture. Two prospective longitudinal studies were conducted to investigate the persistence ofD. nodosusandF. necrophorumin sheep feet, mouths and faeces, and in soil. Molecular tools were used to detect species, strains and communities. In contrast to the existing paradigm,F. necrophorumpersisted on footrot diseased feet, and in mouths and faeces; different strains were detected in feet and mouths.D. nodosuspersisted in soil and on diseased, but not healthy, feet; similar strains were detected on both healthy and diseased feet of diseased sheep. We conclude thatD. nodosusandF. necrophorumdepend on sheep for persistence but use different strategies to persist and spread between sheep within and between flocks. Elimination ofF. necrophorumwould be challenging due to faecal shedding. In contrastD. nodosuscould be eliminated if all footrot-affected sheep were removed and fade out ofD. nodosusoccurred in the environment before re-infection of a foot.
Publisher Correction: An extended cluster expansion for ground states of heterofullerenes
Authors: Cheng Yun-Hua , Liao Ji-Hai , Zhao Yu-Jun , Yang Xiao-Bao
Published: October 2019

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
High-speed, inline measurement of protein activity and inactivation processes by supercontinuum attenuation spectroscopy
Authors: Koch Hanna , Eisen Kristina , Werblinski Thomas , Perlitz Julian , Prihoda Felix , Lee Geoffrey , Will Stefan
Published: October 2019

Determination of catalase activity using supercontinuum attenuation spectroscopy and PLSA.
Low background mould-prepared gelatine standards for reproducible quantification in elemental bio-imaging
Authors: Westerhausen Mika T. , Lockwood Thomas E. , Gonzalez de Vega Raquel , Röhnelt Anna , Bishop David P. , Cole Nerida , Doble Philip A. , Clases David
Published: October 2019

Raw intensities obtained from the ablation of mould-prepared gelatine.
A fast and validated capillary zone electrophoresis method for the determination of selected fatty acids applied to food and cosmetic purposes
Authors: Amorim Tatiane Lima , Pena Mariana Gavioli dos Reis , Costa Fabiano Freire , de Oliveira Marcone Augusto Leal , Chellini Paula Rocha
Published: October 2019

The potential of capillary electrophoresis was demonstrated to the determination of fatty acids in food and cosmetic samples and a validated method is proposed to palmitic, stearic, oleic and linoleic acids quantification in these samples.
Transition metal-free access to 3,4-dihydro-1,2-oxaphosphinine-2-oxides from phosphonochloridates and chalcones through tandem Michael addition and nucleophilic substitution
Authors: Fu Zhicheng , Sun Simin , Yang Anjian , Sun Fang , Xu Jiaxi
Published: October 2019

3,4-Dihydro-1,2-oxaphosphinine 2-oxides are synthesized through tandem intermolecular nucleophilic addition and cyclization of phosphonochloridates and enones in the presence of base.
Atomic layer deposition of ultra-trace Pt catalysts onto a titanium nitride nanowire array for electrocatalytic methanol oxidation
Authors: Sun Junwei , Wang Xin , Song Yanyan , Wang Qianqian , Song Yumei , Yuan Ding , Zhang Lixue
Published: October 2019

Atomic layer deposition of ultra-trace Pt onto three-dimensional titanium nitride nanowire array was realized, and the obtained catalyst shows a much larger mass current density than commercial Pt/C towards electrocatalytic methanol oxidation.
Characterizing solids retention, head loss development and micropollutant removal in the case of direct powdered activated carbon dosage upstream of deep bed filtration
Authors: Krahnstöver Therese , Zenker Armin , Baggenstos Martin , Kobler Bernd , Leikam Knut , Koch Gerhard , Wintgens Thomas
Published: October 2019

The dynamics of micropollutant removal and powdered activated carbon (PAC) separation were studied in a combined PAC/deep bed filtration process.
Correction: The contribution of chemical vapor generation coupled with atomic or mass spectrometry to the comprehension of the chemistry of aqueous boranes
Authors: D’Ulivo Alessandro
Published: October 2019

Correction for ‘The contribution of chemical vapor generation coupled with atomic or mass spectrometry to the comprehension of the chemistry of aqueous boranes’ by Alessandro D’Ulivo et al., J. Anal. At. Spectrom., 2019, 34, 823–847.
Chemical imaging and assessment of cadmium distribution in the human body
Authors: Egger Alexander E. , Grabmann Gerlinde , Gollmann-Tepeköylü Can , Pechriggl Elisabeth J. , Artner Christian , Türkcan Adrian , Hartinger Christian G. , Fritsch Helga , Keppler Bernhard K. , Brenner Erich , Grimm Michael , Messner Barbara , Bernhard David
Published: October 2019

Adipose and muscle tissue – so far underestimated – contribute to the total Cd burden. Cd distribution in testis and kidney correlates with the histologic blood-testis-barrier and renal excretion, respectively.
3D printed electrodes for efficient membrane capacitive deionization
Authors: Vafakhah Sareh , Sim Glenn Joey , Saeedikhani Mohsen , Li Xiaoxia , Valdivia y Alvarado Pablo , Yang Hui Ying
Published: October 2019

3D printed electrodes for cost-effective and energy-efficient desalination technologies.
Anomalous phase transition behavior in hydrothermal grown layered tellurene
Authors: Li Han , Wu Kedi , Yang Sijie , Boland Tara , Chen Bin , Singh Arunima K. , Tongay Sefaattin
Published: October 2019

Recent studies have demonstrated that tellurene is a van der Waals (vdW) two-dimensional material with potential optoelectronic and thermoelectric applications as a result of its pseudo-one-dimensional structure and properties.
Multidimensional chromatographic analysis of carboxylic acid-functionalized polyethylene
Authors: Ndiripo Anthony , Pornwilard M.-M. , Pathaweeisariyakul Thipphaya , Pasch Harald
Published: October 2019

Carboxy-functionalized polyethylene is comprehensively analysed using a multidimensional fractionation approach based on high-temperature HPLC, two-dimensional liquid chromatography and selective infrared detection.
Synthesis of block copolymers using poly(methyl methacrylate) with unsaturated chain end through kinetic studies
Authors: Chang Jun Jie , Niino Hiroshi , Chatani Shunsuke , Goto Atsushi
Published: October 2019

Kinetic studies aided the controlled synthesis of PMMA block copolymers and PMMA branched copolymers from a PMMA containing an unsaturated chain end.
Unravelling the polydopamine mystery: is the end in sight?
Authors: Lyu Qinghua , Hsueh Nathanael , Chai Christina L. L.
Published: October 2019

Mass spectroscopic studies using deuterium-labeling reveal a novel structure for polydopamine, deriving from dopaminochrome and uncyclized dopamine.
NG tank contribution in the integrated energy networks
Authors: Hamedi A. , Seifi A.R.
Published: October 2019

The energy saving and optimal operation of energy networks are essential issues in today's system management studies. A kind of natural gas (NG) storages called NG tank is presented in this Letter. The NG tank is modelled and formulated in the integrated energy network in a way that it can improve the optimal operation of an energy network as well.
FPGA‐based synchronising control system design for spinning disk confocal image scanning microscope
Authors: Qin S.
Published: October 2019

In this Letter, a field programmable gate array (FPGA)‐based synchronising control system design for spinning disk confocal image scanning microscope is described. Based on the analysis on the condition of laser triggering, the author simplifies the design by transforming the floating‐point calculation formula to a very simple form of integer calculation, which can then be implemented by fixed‐point calculation on FPGA without trimming any bit, for which there is no computational precision loss. The testing of simulation and experiment shows that the design is very accurate and reliable.
Synthesis of sparse planar arrays in the whole field by compressed sensing
Authors: Zhao Dongdong , Chen Peng , Hu Yingtian , Liang Ronghua , Wang Haixia , Guo Xinxin
Published: October 2019

A method for designing sparse large planar arrays in whole field with a minimum number of elements is proposed in this Letter. The method is developed by compressed sensing algorithms and a new composite beam pattern covering both far‐ and near‐field information. The experimental results demonstrate that the sparse planar array achieves a 95.3% element thinning compared to the fully sampled planar array and the side lobe peaks in near‐field conditions are at least 3.4 dB lower than those in previous studies.
Optically transparent sea‐water monopole antenna with high radiation efficiency for WLAN applications
Authors: Phan D.T. , Jung C.W.
Published: October 2019

A high efficiency and transparent sea‐water monopole antenna operating at 2.4 GHz for wireless local area network (WLAN) applications is proposed in this Letter. The antenna has high transparency (>85%) achieved by using sea‐water as its conductive medium contained within a clear acrylic tube. To improve the radiation efficiency of the antenna, a short metal tube with a metal disk at the base was loaded into a feeding probe to achieve greater excitation. The antenna is simulated and its properties are verified through this experiment. Measurement results show a −10 dB bandwidth of 1.1 GHz (2.1–3.2 GHz) and a high radiation efficiency (>71%) over the entire WLAN band (2.4–2.5 GHz). These results demonstrate the proposed antenna as an attractive alternative to conventional metal monopoles for WLAN applications.
5‐GHz integer‐N PLL with spur reduction sampler
Authors: Biswas D. , Javed G.S. , Reddy K.S.S.
Published: October 2019

In this work, a 5‐GHz current‐controlled ring oscillator based integer PLL is implemented with a spur reduction sampler to reduce the reference spurs. The sampler can have taps with each tap sampling the oscillator's control voltage at offsets of the reference phase. The sampler introduces bandstop notches at the frequencies where the spurs appear. The samplers are capable of reducing the spurs from to , a reduction by 50 dB, as evident from simulation results performed in 28 nm technology.
Performance analysis of non‐orthogonal multiple access based‐satellite communication networks with hardware impairments and channel estimations
Authors: Zhou Feng , Wang Rugang , Bian Jinhong
Published: October 2019

This Letter investigates the impacts of hardware impairments (HIs) and channel estimation errors (CEEs) on the performance of non‐orthogonal multiple access (NOMA)‐based satellite communication networks. Especially, the authors obtain the closed‐form expression of the outage probability (OP) of the considered NOMA‐based satellite communication networks. Furthermore, in order to analyse the effects of HIs and CEEs in high signal‐to‐noise ratios (SNRs) regime, they derive the asymptotic expression of OP at high SNRs, which provide efficient and fast ways to evaluate the impact of system parameters on the system performance. In addition, Monte Carlo simulations are provided to verify the correctness of the analytical results.
Scaled‐time OFDM experiments for channels exceeding the cyclic prefix
Authors: Lerch M. , Caban S. , Zöchmann E. , Svoboda P. , Rupp M.
Published: October 2019

Wireless communications experiments at high user velocities can be performed with much less effort at lower velocities by using time‐stretching techniques. In OFDM, state‐of‐the‐art time‐stretching techniques do not consider the case of channel impulse responses exceeding the length of the cyclic prefix (CP). This is the case in any real‐world OFDM system. In particular, multipath scenarios caused by relay nodes commonly found in public railways have a late, strong channel tap. In this work, the authors propose a time‐stretching technique that preserves the effects of the insufficient CP with negligible error and without channel knowledge.
Analogue circuit fault diagnosis based on convolution neural network
Authors: Du Tao , Zhang Hao , Wang Ling
Published: October 2019

In order to simplify the process of analogue circuit fault diagnosis under the premise of improving the fault diagnosis rate of analogue circuit, and to deeply mine the fault characteristics of the output signal, a fault diagnosis method based on convolutional neural network (CNN) is proposed. The output signals in different fault states are directly input into CNN for fault feature extraction and fault classification. By optimising the CNN model and its parameters, the 100% fault diagnosis rate of Sallen‐Key circuit can be achieved. The experimental results indicate that the CNN‐based analogue circuit fault diagnosis method simplifies the fault diagnosis process and improves the fault diagnosis rate.
Planar patch antenna system with high isolation for full‐duplex applications
Authors: Nguyen T. , Karacolak T.
Published: October 2019

In this Letter, a differential‐fed planar antenna system is presented with large isolation between transmission and reception ports for full‐duplex applications. The proposed system contains two antenna pairs, each of which is composed of two identical single‐ended microstrip patch antennas operating at 12 GHz. Each element in the array is fed 180° out‐of‐phase by utilising rat‐race hybrid couplers making the whole system differential‐fed. The patch antenna array and the hybrid ring couplers are designed on two separate substrate materials with the ground plane in between. Simulation results show high isolation through the entire band of interest while measured results approach in a reflective environment. The design also exhibits good impedance matching, reasonable gain values, and high efficiency.
Semi‐blind MIMO‐OFDM channel estimation using expectation maximisation like techniques
Authors: Ladaycia Abdelhamid , Belouchrani Adel , Abed‐Meraim Karim , Mokraoui Anissa
Published: October 2019

This study deals with semi‐blind (SB) channel estimation of multiple‐input multiple‐output orthogonal frequency‐division multiplexing (MIMO‐OFDM) system using maximum likelihood (ML) technique. For the ML cost optimisation function, new expectation maximisation (EM) algorithms for the channel taps estimation are introduced. Different approximation/simplification approaches are proposed for the algorithm's computational cost reduction. The first approach consists of decomposing the MIMO‐OFDM system into parallel multiple‐input single‐output OFDM systems. The EM algorithm is then applied to estimate the MIMO channel in a parallel way. The second approach takes advantage of the SB context to reduce the EM cost from exponential to linear complexity by reducing the size of the search space. Finally, the last proposed approach uses a parallel interference cancellation technique to decompose the MIMO‐OFDM system into several single‐input multiple‐output OFDM systems. The latter are identified in a parallel scheme and with a reduced complexity. The performance of the proposed approaches are discussed, assessed through numerical experiments and compared with respect to the Cramèr Rao Bound and to other EM‐based solutions reported in the literature.
T_CAFE: A Trust based Security approach for Opportunistic IoT
Authors: Kandhoul Nisha , Dhurandher Sanjay K. , Woungang Isaac
Published: October 2019

Internet of things (IoT) is a revolution of the internet where a group of computing devices, sensors, machines or people, having unique identifiers and the ability to transfer data over the network without human intervention, are interconnected. Opportunistic networks (OppNets) are a type of disruption‐tolerant networks, where network topology is not fixed and the devices are connected intermittently. Opportunistic IOT (OppIoT) is a blend of OppNets and IoT networks, where the data are shared among IoT devices and human communities exploiting the opportunistic contact nature of humans. The data is usually transmitted in a broadcast manner, exposing it to all the members of the network. Thus, securing the data transmitted is of utmost importance in OppIoT. This article proposes a trust‐based schemE (called T_CAFE) for securing the network against several attacks like sybil, bad mouthing, good mouthing, black hole and packet fabrication attacks. Using the opportunistic network environment simulator for performing simulations, it is found that the proposed T_CAFE protocol enhances the network security and outperforms routing protocols such as SHBPR, RSASec and ATDTN in terms of legitimate packet delivery, higher probability of message delivery, lower count of dropped messages and lower value of latency in packet delivery.
Robust control approach for handling matched and/or unmatched uncertainties in port‐controlled Hamiltonian systems
Authors: Binazadeh Tahereh , Karimi Mahsa , Tavakolpour‐Saleh Ali Reza
Published: October 2019

This study considers the problem of robust interconnection and damping assignment passivity‐based control approach (IDA‐PBC) for underactuated mechanical systems from two points of view. First, the robustness of IDA‐PBC in the presence of non‐vanishing matched and unmatched uncertainties is analysed and sufficient conditions are derived to ensure ultimate boundedness of system. Second, the robust control design is provided by adding a new control input to the former controller designed by IDA‐PBC, such that asymptotic stability of the closed‐loop system in the face of non‐vanishing matched uncertainties is fulfilled. Finally, the proposed robust controller is evaluated through simulations of two practical examples, i.e. an inertia wheel pendulum and a single‐link elastic joint robot. The simulation outcomes clearly reveal the effectiveness of the presented robust controller.
Robust stabilisation of linear time‐invariant time‐delay systems via first order and super‐twisting sliding mode controllers
Authors: Ramírez Jerónimo Luis F. , Zenteno Torres Jazmín , Saldivar Belem , Dávila Jorge , Ávila Vilchis Juan Carlos
Published: October 2019

This study presents a novel scheme for the synthesis of first‐order and super‐twisting sliding mode controllers for the robust stabilisation of a class of linear time‐invariant time‐delay systems subject to matched disturbances. Starting from a stability analysis of the system to guarantee that the resulting sliding mode dynamics is asymptotically stable, linear matrix inequality conditions of reduced conservatism are derived by using the Lyapunov–Krasovskii approach. Based on the stability analysis, the sliding mode controllers are synthesised to force the evolution of the closed‐loop system trajectories to converge onto a prescribed sliding surface and to ensure that they remain there for all subsequent time. Unlike existing results, the implementation of the proposed approach does not involve strong requirements on the system structure. A numerical and a practical example along with a comparative analysis prove the effectiveness of the proposal and highlight its benefits.
Periodicity and stability analysis of periodic switched positive systems
Authors: Li Shuai , Liu Xingwen
Published: October 2019

Addressed in this study are the minimal period and stability issues of periodic switched positive systems. With the assumption that all the system matrices, delays and switching signal are periodic, it is shown that the considered switched system is also periodic with the minimal period being a divisor of the least common multiple of the periods of subsystems and switching signal, and an algorithm is presented to determine the minimal period. Then some necessary and sufficient exponential stability conditions are proposed for periodic switched positive systems. These conditions are also extended to a more general class of periodic switched systems. Finally, a numerical example with three cases is provided to demonstrate the effectiveness of the theoretical results and reveals two interesting facts: The system matrices of periodic positive systems are unnecessarily non‐negative and system delays influence system stability. These facts imply that there exist some remarkable differences between general switched positive systems and periodic switched positive systems.
Attention‐based spatial–temporal hierarchical ConvLSTM network for action recognition in videos
Authors: Xue Fei , Ji Hongbing , Zhang Wenbo , Cao Yi
Published: October 2019

Human action recognition in videos is an important research topic in computer vision due to its wide applications. Actions naturally contain both spatial and temporal information. The key to action recognition is to model the spatial and temporal structures of actions. In this study, the authors propose an attention‐based spatial–temporal hierarchical convolutional long short‐term memory (ST‐HConvLSTM) network to model the structures of actions in the spatial and temporal domains. The ST‐HConvLSTM consists of two parts: a spatial–temporal attention module and a novel LSTM‐like architecture named hierarchical ConvLSTM (HConvLSTM). The HConvLSTM can model the spatial and temporal structures of actions. The spatial–temporal attention module can figure out which part of the video is more discriminative for action recognition and makes the HConvLSTM focus on it. In addition, a weighted fusion strategy is proposed to fuse the appearance information and motion information of the video. The proposed ST‐HConvLSTM is evaluated on UCF101, HMDB51 and Kinetics datasets. Experimental results show that the authors’ proposed ST‐HConvLSTM achieves state‐of‐the‐art performance compared with other recent LSTM‐like architectures and attention‐based methods.
Explicit MPC for column‐type EPS systems
Authors: Lee Junho , Chang Hyuk‐Jun , Ahn Hyun‐Sik
Published: October 2019

For decades, electric power steering (EPS) systems have replaced hydraulic‐assist steering systems. The main purpose of EPS systems is to generate an assist torque using an electric motor for the improvement of the driving comfort. The proposed controller is designed against a model predictive control (MPC) and linear quadratic regulator (LQR) for a comparison in terms of generating a desired value of the assist torque. The motion equations of a column‐type EPS system are derived in this study. Meanwhile, MPC has been regarded as an effective control method for constrained problems because this method can anticipate future events of the system. However, the repeated online optimisation imposes huge computational complexity. The proposed scheme explicitly obtains the current control law by adopting a multi‐parametric quadratic programming technique. The proposed controller is evaluated in MATLAB/Simulink and a hardware‐in‐the‐loop simulation using the Infineon automotive TriCore AURIX TC277 microcontroller. The simulation and experimental results confirmed that the proposed controller successfully tracks the reference value while reducing the computational burden. It is also shown by conducting experiments with various vehicle speeds that the tracking ability of the explicit model predictive controller (MPC controller) is superior to that of the LQR controller.
Novel fast and secure approach for reverse power protection in synchronous generators
Authors: Samami Mehdi , Azari Milad Niaz
Published: October 2019

The purpose of the reverse power (RP) protection is essentially to prevent severe damage to the generator prime mover. For this aim, directional relays are usually utilised. RP condition (RPC) leads to initial oscillations of power and frequency which might exceed the RP threshold and lead to mal‐operation of the relay. Therefore, assigning a time delay is essential to reduce the oscillations. However, this strategy increases the relay trip time, which leads to enhancing the motoring time and the risk of damage to the prime mover. This study proposes a novel algorithm to detect RPC in synchronous generators, based on some easily accessible quantities including active power (P), load angle (), internal voltage (), terminal voltage (V) and the phase difference between voltage and current (). This scheme utilises two criterions including the sign of and also comparing V with tangential component of on V (). This algorithm is independent of the size and type of load and is also capable of discriminating RPC with other potential faults. The performance of the proposed approach has been verified with Matlab software and the obtained simulation results show the fastest operation and highest reliability of the proposed technique compared to others.
Multivariable sliding‐mode extremum seeking PI tuning for current control of a PMSM
Authors: Fartash Toloue Shirin , Kamali Seyed Hossein , Moallem Mehrdad
Published: October 2019

High‐performance current control is critical for obtaining smooth output torque in permanent‐magnet synchronous motors (PMSMs). To this end, a new proportional–integral (PI) tuning method based on multivariable sliding‐mode extremum seeking is proposed in this study and applied for current control of a PMSM. In the proposed method, a sliding‐mode extremum seeking optimiser varies the PI gains by minimising a cost function based on the feedback error term. The resulting PI controller can achieve fast and accurate tracking response, high disturbance rejection, and low sensitivity to PMSM parameter variations. The stability of the proposed control strategy is investigated through a Lyapunov analysis and its performance is evaluated through experimental studies. The results indicate that the proposed controller can offer improved performance in terms of accuracy, parametric variations, and load torque disturbances when compared with a conventional PI and a recently proposed PI controller using the gradient‐based extremum seeking tuning method.
Compensation analysis of longitudinal end effect in three‐phase switched reluctance linear machines
Authors: Nie Rui , Chen Hao , Liu Jinfu , Zhao Wenmin , Wang Xing , Palka Ryszard
Published: October 2019

The longitudinal end effect of switched reluctance linear machine (SRLM) makes the electromagnetic characteristics of different phases unbalanced, especially in magnetic flux distributions. These discrepancies unbalance phase currents and aggravate the force ripple of SRLM, which are verified on a double‐sided SRLM. This study aims to analyse the influence of the longitudinal end effect on SRLMs and to investigate simple but practical compensation methods for the performance improvement of linear machines. Through magnetic circuit analysis, a new compensation method which is widening stator end poles is proposed for the first time. Three‐dimensional finite element analysis (3D FEA) shows that this new method can decrease the force factor by about 93.9%, while the previously used method which is adding auxiliary stator poles can decrease the force ripple factor by only about 27.5%. In addition, the proposed method needs less extra space than the previous method. Hence, the new compensation method is more practical and more efficient. Furthermore, the theoretical value of optimal width of stator end poles is expressed, and its effectiveness is confirmed by sensitivity analysis.
Two‐stage optimal scheduling for aggregators of batteries owned by commercial consumers
Authors: Wang Zeyu , Kirschen Daniel S.
Published: October 2019

This study proposes a two‐stage optimisation technique to schedule batteries owned by commercial consumers through an aggregator. This approach captures energy arbitrage and peak shaving benefits at the consumer level, as well as frequency regulation benefit at the system level. The day‐ahead stage optimisation maximises the expected profits, considering the battery degradation cost as well as the uncertainties on customer demand profiles and frequency regulation prices. It determines the regulation capacity that the aggregator can bid at each hour, as well as the consumers’ peak demand targets and battery state‐of‐charge (SoC) target trajectories. The near real‐time stage involves two steps: a rule‐based pre‐process and a snapshot optimisation. It dispatches the batteries to follow the aggregator regulation capacity bids, to track the SoC target trajectories and to ensure that the peak demand targets are not violated. A case study demonstrates that the proposed two‐stage approach effectively dispatches batteries to achieve both consumer and system‐level benefits.
Image‐independent optimal non‐negative integer bit allocation technique for the DCT‐based image transform coders
Authors: Thakur Vikrant Singh , Thakur Kavita , Gupta Shubhrata , Rao Kamisetty R.
Published: October 2019

The optimum non‐negative integer bit allocation (ONIBA) is an important technique, which provides optimal quantisation of transform coefficients for the image transform coders (ITCs). However, the existing ONIBA algorithms are still not popular for the discrete cosine transform (DCT)‐based ITCs, due to their image‐dependent nature and additional side information requirements. Therefore, this study presents a novel image‐independent ONIBA (IIONIBA) technique to achieve efficient quantisation for the DCT‐ITCs. For the development of the proposed IIONIBA technique, initially, an image‐dependent ONIBA algorithm is proposed, which is then mapped into desired image‐independent solution via utilisation of a prepared combined image and proposed modified step size mapping technique. Thereafter, a new lookup table for the elements of quantisation tables, obtained from the proposed IIONIBA technique, is established using non‐linear regression analysis, to reduce the problem of additional side information requirements. Several experiments are performed to evaluate the performance of the proposed IIONIBA technique based on the visual quality assessment of reconstructed images and the image quality indexes peak signal to noise ratio (PSNR) and mean structural similarity index (MSSIM). The results show that the proposed IIONIBA technique delivers better quantisation and provides significant gains in the image quality indexes as compared to the recent quantisation techniques.
Enhancement of variably illuminated document images through noise‐induced stochastic resonance
Authors: Javed Mohammed , Bhattacharjee Tryambak , Nagabhushan Panduranga
Published: October 2019

The presence of noise is generally believed to suppress the actual signal, and subsequently, deteriorate the quality of the signal or image. However, this study counter argues, and proposes a novel technique of enhancing variably illuminated document images through the addition of external noise, using the famous physical phenomenon of stochastic resonance. Here, the fundamental relationship between inherent parameters of a dark and low contrast image, and the intensity of external noise‐induced to produce best contrast enhancement is systematically modelled using regression line parameters. With this, the amount of noise to be added is automatically predicted, and is utilised to enhance the dark and low contrast document images. The proposed enhancement technique using noise‐induced (non‐dynamic) stochastic resonance is computationally very efficient, unlike the existing methods which estimate the optimum value of noise to be added through a time‐consuming iterative method. The efficacy of the developed technique is demonstrated through experimental results. Overall, a mathematical model for predicting the optimum noise standard deviation (NSD), and subsequently three variants of image enhancement algorithms based on global‐NSD, partition‐NSD and mask‐NSD are the major contributions reported in this research work.
Microstrip patch back radiation reduction using metamaterial superstrate
Authors: Jafargholi Amir , Jafargholi Ali , Choi Jun H. , Veysi Mehdi , Soleimani Ali
Published: October 2019

The capability of the capacitively loaded loop (CLL) metamaterial (MTM) superstrate to attenuate surface waves thereby reducing the back radiation of microstrip patch antennas is examined. To understand the surface wave suppression mechanism, theoretical approaches of a grounded dielectric slab waveguide is provided. Both theoretical and numerical analyses show that the proposed superstrate causes a drastic attenuation of surface wave propagation. To confirm the numerical simulations, the proposed antenna is fabricated and tested. The dimensions of the CLL‐MTM covered patch antenna are 0.6λ × 0.8λ × 0.14λ. The radiated gain and efficiency are measured at 7.8 dB and 95%, respectively. Measurements show that the front‐to‐back ratio is enhanced by more than 12 dB. In comparison with the patch antenna without the CLL‐MTM superstrate, the proposed antenna reduces the gain and efficiency by less than 0.1 dB and 2%, respectively.
Extremely electrically small MF/HF antenna
Authors: Nikkhah Nastouh , Zakeri Bijan , Abedi Hajar
Published: October 2019

This study presents an extremely small frequency‐tunable monopole antenna operating at medium frequency/high frequency (MF/HF) band with an omnidirectional radiation pattern. Most of the existing miniaturisation techniques operate at low bandwidth as well as low efficiency. The design is based on a capacitive top, allowing the antenna to resonate at much lower frequencies, and a tunable inductive centre loaded. Utilising the capacitive top, the radiation resistance of the antenna is significantly increased. The resonant frequency can be tuned over a wide range of frequency (0.974–30 MHz) without changing the antenna total size by virtue of the tunable loading coil. The tuning system contains arms, motors, contactor, microcontroller and remote control. The experimental results are 0.0032 λ, ka = 0.01, |S11| = − 15.8 dB, gain = −13.9 dBi and ɳ = 2.2% at its lowest resonant frequency.
Speed sensorless control strategy for six‐phase linear induction motor based on the dual reduced‐dimensional serial extended Kalman filters
Authors: Sun Xingfa , Nie Ziling , Zhu Junjie , Han Yi , Sun Jun
Published: October 2019

This study proposes a speed sensorless vector control strategy for the six‐phase linear induction motor (SPLIM) based on the dual reduced‐dimensional serial extended Kalman filters (DRDSEKFs). Firstly, the low‐order mathematical model of SPLIM is obtained according to the equivalent transformation of primary voltage, current and flux components in the stationary coordinate system. Then, the state equation is derived and the speed estimation based on the five‐dimensional extended Kalman filter (EKF) is realised. To reduce the computation cost and improve the accuracy of speed estimation, a DRDSEKFs algorithm is proposed, with one two‐dimensional EKF and one three‐dimensional EKF operating serially in every control period. As the real‐time performance of the algorithm is guaranteed, it is possible to overcome the hysteretic nature of the traditional EKF and improve the dynamic estimation performance. Simulations and experiments show that the proposed sensorless control strategy is feasible and effective.
RBPPFF for robust TAN
Authors: Lim Jong Nam , Park Chan Gook
Published: October 2019

Terrain‐aided navigation (TAN) is a technique for position estimation based on altimeter and digital elevation model measurements. To perform TAN, non‐linear filters such as a particle filter (PF) or a point mass filter (PMF) are mainly used owing to the non‐linearity of measurements and systems. In particular, owing to the degradation of the global positioning system or sensors and the non‐linearity of maps and measurements, an initial state error or sudden state change may occur. The authors propose a Rao‐Blackwellised particle‐point mass fusion filter (RBPPFF) that performs robustly in the presence of such initial state errors or sudden state changes with low computational complexity in real time. The RBPPFF combines the advantages of a PF and PMF, and it employs Rao‐Blackwellisation to efficiently increase the number of states. To develop the RBPPFF, the formulae of the RBPF and Rao‐Blackwellised point mass fusion filter (RBPMF) are derived using the same conventions, and a method is presented for an effective fusion of the PF and the PMF. Finally, the performance of the proposed algorithm is demonstrated through Monte Carlo simulation across various environments with filters such as PF, PMF, RBPF, and RBPMF.
GIS mechanical state identification and defect diagnosis technology based on self‐excited vibration of assembled circuit breaker
Authors: Ma Hongzhong , Liu Baowen , Xu Honghua , Chen Bingbing , Ju Ping , Zhang Li , Qu Bin
Published: October 2019

Condition monitoring has been widely used to detect electrical faults of gas‐insulated switchgear (GIS), but little attention has been paid to diagnosing the mechanical failures. Owing to the fact that the operating energy of circuit breaker assembled in GIS is large enough to stimulate the whole GIS to vibrate, in this study, non‐invasive techniques for evaluating the mechanical condition of GIS by considering the vibration signals excited by the operation of circuit breaker are implemented. Vibration signatures of five typical mechanical failures sated on both static mechanisms and drive mechanisms were extracted from a 126kV GIS test system. In addition, new algorithms for signal processing and decision‐making techniques based on the combination of energy equipartition S‐transform and particle swarm optimisation support vector machine classifier were proposed. A practical diagnostic instrument was developed and applicated on line for identifying the GIS mechanical condition. Experimental and field demonstration verified the effectiveness of the proposed GIS mechanical fault‐diagnosis technology.
Investigation of AC breakdown properties of paper insulators and enamel insulation impregnated with rice oil, corn oil and peanut oil for transformers
Authors: Nguyen Dung Van , Nguyen Long Phuoc , Quach Thinh Ngoc
Published: October 2019

The AC breakdown properties of Kraft paper, pressboard and the enamel insulation layer in riceoil, peanut oil and corn oil were investigated under both new and agedconditions. The ageing of paper insulators and the enamel insulation layer inoils with the open cup method was carried out at 130 oC for 500 h in an aircirculation oven. The puncture breakdown strength was determined by varying thenumber of layers and thickness of Kraft paper, while various electrode gapdistances were used to measure the surface breakdown strength. Experimentalresults show that the breakdown strength and the tensile strength of paperinsulators impregnated with these vegetable oils are comparable to that inmineral oil, and the surface breakdown strength of paper insulators is slightlyaffected by types of impregnating oils. The ageing significantly reduces boththe breakdown strength and the tensile strength of paper insulators ininvestigated oils. In addition, it was also found that the enamel layer invegetable oils withstood higher puncture breakdown strength than in mineral oil,and the ageing process significantly reduced the puncture breakdown strength ofthe enamel layer. This enamel layer was observed to markedly enhance the surfacebreakdown strength of pressboard.
FPGA implementation of adaptive p‐norm filter for non‐stationary power signal parameter estimation
Authors: Nanda Sarita , Pattnaik Ansuman , Dash Pradipta Kishore
Published: October 2019

A p‐norm extreme learning machine (ELM) based on sparsity constraint is presented in this study for tracking of fundamental frequency, harmonic and dc in current power signals which finds application in phasor measurement units for wide area power network in smart grid environment. Real‐time power applications typically are furnished with on‐board controller and hence have constraints to stock a complex architecture. Moreover, the data from online practices are polluted by noises of diverse statistical features obtained on a sample‐by‐sample basis. Hence, approaches with improved learning paradigm and close model dealing with noises of varied statistical characteristics are essential. The proposed approach formulates a cost function with recursive p‐norm error criterion and sparsity penalty that updates the output weights in succession besides adjusting some coefficients of the output weights to zeros that promotes quicker convergence and higher accuracy results. Exhaustive computer simulations have been carried out with synthetic signals and real‐time signals to track the dynamic changes in the power signal amplitude, phase and frequency that demonstrate the accuracy, efficiency and robustness of the proposed p‐norm ELM. Additionally, the new ELM network also is validated on a field programmable gate array (FPGA) hardware to prove its practicability towards current developments on phasor measurement units.
0.8‐V 1.4‐nW multi‐decade frequency range true RMS to DC converter based on two‐quadrant current squarer circuit
Authors: Maryan Mohammad Moradinezhad , Azhari Seyed Javad , Ayatollahi Ahmad , Sajadinia Hamed
Published: October 2019

A low‐voltage ultra‐low‐power two‐quadrant current squarer based‐true RMS to DC converter circuit is presented in this study. The proposed current squarer is based on two translinear loops with matched NMOS transistors operating in the weak inversion region. Ultra‐low‐power dissipation of 1.4 nW, multi‐decade frequency range of 0.5 Hz–55 kHz and large input dynamic range of 72 pA–1 nA (with error <3%) are the main achievements of the proposed design while constructed of only ten transistors. Post‐layout simulations with 0.8‐V supply voltage using HSPICE software in 0.18 μm TSMC CMOS process (level‐49 parameters) verified the good functionality of the proposed circuit. Moreover, Monte Carlo analysis is performed to validate the satisfactory PVT robustness and reliability of the design's performance.
On RF localisation deception capability of FDA signal under interferometry reconnaissance
Authors: Zhang Xihui , Yan Yisheng , Wang Wen‐Qin , Zhang Shunsheng
Published: October 2019

Phased‐array antennas are known for their capability to electronically steer a beam with high effectiveness, but beam steering is fixed in an angle for all range cells. Different from that, frequency diverse array (FDA) offers a range‐angle‐dependent beam‐pattern. The use of a small frequency increment across its array elements to generate an array factor that is a function of the angle, time, and range, allowing the FDA antenna to form focusing beampattern to the desired range and angle region. Aiming to resolve the problem that traditional phased‐array radars can be easy detected and localised by undesired reconnaissance receiver, the use of FDA instead of phased‐array provides potential radio frequency (RF) stealth capability. Here, the authors analyse the RF localisation deception performance under interferometry reconnaissance for undesired receivers, which RF stealth capability is validated by the numerical results.
High‐speed moving target detection and tracking method based on speed estimation
Authors: Zhang Jinquan , Li Jingwen , Ma Haizhong , Wang Ye
Published: October 2019

During the detection and tracking of high‐speed moving target by radar, the coherent accumulation and the energy accumulation of target echo signal are poor. In order to solve this problem, this study discusses speed estimation based on the Hough transform, correction across distance of radar echo signal and pre‐tracking detection method based on dynamic programming. The authors propose an energy accumulation method of target echo based on speed estimation. Using this method, speed estimation accuracy reaches 98.87%, signal‐to‐noise ratio increases by 10 dB and the goal amplitude is 4.81 times more than the original amplitude. Simulation results show that this method can improve the energy accumulation effectiveness and improve detection and tracking ability of high‐speed moving target by radar.
Sensor selection for target tracking based on single dimension information gain
Authors: Wang Huan , Ge Jianjun , Zhang De , Liu Guanghong
Published: October 2019

In sensor management for target tracking, the existing sensor selection methods based on information entropy generally select the sensor that brings the most information gain for target; however, for multi‐dimension state vector of target, information gain for target in the specified dimension cannot be guaranteed. For the ambiguity problem in the measure for multi‐dimension state vector using information entropy, this study proposes a sensor selection method based on single dimension information gain of the target, which uses particle filter to compute the marginal probability density of target state in the specified dimension and exploits the Kullback–Leibler divergence to measure the information gain of target in the specified dimension, in such a way, by selecting the sensor that brings the most information gain for target in the specified dimension. The proposed method can guarantee higher tracking accuracy gain of target in the specified dimension and obtain more reliable tracking results. Experiment results illustrate that the proposed method has a higher track accuracy of position and velocity in the specified dimension than sensor selection method based on target state entropy.
Anti‐multipath interference method of semi‐active seek
Authors: Tian Gui Long , Tong Chuang Ming , Liu Hao , Long Zheng Guo , Wang Jiang Jun
Published: October 2019

Multipath interference is the main factor which has influence in super‐low‐altitude detection. Aiming at solving the problem of detection for super‐low‐altitude target, anti‐multipath methods under concrete environment are studied here. First, antenna radiation pattern of seeker is introduced to modify traditional four‐path method. Then, the hybrid method combining physical optics (PO) and method of equivalent currents (MEC) is used to calculate the scattering electric field of target. Compared to the method of moment (MoM), the PO + MEC hybrid methods are of high accuracy. Finally, the multipath interference scattering from interaction between the target and the environment under the condition is studied and analysed in detain. The simulation results are useful in military application.
Experimental research of passive bistatic radar based on pipeline processing
Authors: Zheng Guangyong , Wang Huabing , Li TingPeng
Published: October 2019

For passive bistatic radar (PBR), it is convenient to use software method to realise the signal processing. However, because of the huge amount of data computing, it is difficult to achieve the real‐time signal processing by software method only with server that uses CPU for calculation. To solve the problem, the PBR signal processing method with multi‐CPUs based on pipeline processing is studied. The key point of the method is to improve the parallelism of the signal processing algorithm and to use all the CPU cores efficiently for parallel computing. The whole PBR signal processing is divided into several steps, such as clutter cancellation, correlation processing, CFAR detection and so on, and each step employs different CPU resources that contain many cores. The data processed in each steps is also divided into several pieces to fully use all the CPU cores. At last, the signal processing in software for digital television terrestrial broadcasting (DTTB) signal is achieved based on the method. The experiment is carried out to verify the method. In the experiment, the whole signal processing time for DTTB signal is much less than the time of signal to be processed, and the signal processing output is continuous.