bluuebunny/crossref_metadata_2025_split huggingface dataset:
Graph wavelet transform for image texture classification
Authors: Qiao Yu‐Long , Zhao Yue , Song Chun‐Yan , Zhang Kai‐Ge , Xiang Xue‐Zhi 
Published: April 2021

AbstractGraph is a data structure that can represent complex relationships among data. Graph signal processing, unlike traditional signal processing, explicitly considers the structure and relationship among the signal samples. Graph wavelet transform can provide a multiscale analysis for the graph signal. It is well known that texture is a region property in an image, which is characterized with the intensity and relationship among pixels. In this context of the graph signal processing framework, an image texture can be considered as the signal on the graph. Therefore, a texture classification method based on graph wavelet transform is proposed. Specifically, image textures are decomposed into multiscale components by using two‐channel graph wavelet filter banks. Then the local singular value decomposition is applied to each subband. In order to improve the noise‐resistant ability, the maximum, mean and median values of the local singular values of graph‐wavelet transformation coefficients are extracted. Finally, the Weibull distributions are used to model those extracted values to describe the image textures. The experiments on the benchmark texture datasets are conducted to demonstrate the effectiveness of the proposed method.
Shadow detection from images using fuzzy logic and PCPerturNet
Authors: Chaki Jyotismita 
Published: April 2021

AbstractShadow detection is a challenging and essential task for interpreting the scene. Regardless of encouraging findings from current Deep Learning (DL) approaches used for shadow detection, the methods are also dealing with inconsistent situations where the visual representation of non‐shadow and shadow regions is equivalent. In this article, a DL based approach is introduced for image pixel‐level shadow detection. The proposed CNN‐based approach, pattern conserver convolutional neural network (PCPerturNet) profits from a new design where shadow features are defined utilizing an effective skip‐connection mapping arrangement. To make PCPerturNet robust from the change in brightness and contrast, several perturbed instances are generated by using a fuzzy‐logic based method to train the system. Also, five types of augmentations are applied to images during training to make the system robust from the change in scale, orientation and flip. PCPerturNet derives and conserves shadow patterns in manifold layers and uses those layers progressively in several units to produce the shadow mask. The output of the proposed method is tested on two freely accessible databases and one self‐created database where the accuracy rate obtained is 96.4%, 96.8%, and 89.4% which indicates that the proposed method outperforms the other shadow detection approaches used in the literature.
ILBPSDNet: Based on improved local binary pattern shallow deep convolutional neural network for character recognition
Authors: Lee Shih‐Hsiung , Yu Wei‐Fu , Yang Chu‐Sing 
Published: April 2021

AbstractThis paper proposes an architecture based on the improved local binary pattern (LBP) shallow deep convolution neural network, which integrates hand‐crafted feature pre‐processing and the advantage of character learning in the supervised high‐level function of CNN, in order to enhance its performance. This study introduced the information of scale space into the LBP to reduce the sensitivity to noise, and applied feature maps with two features, the maximum selection feature map (MLBP) and the first selection feature map (FLBP). The former selected the edge with the strongest intensity to reduce the influence of noise points, while the latter measured local binary features through the scale detection of an effective edge. In the network architecture design, according to the differences of input features, networks of different depths were used for learning, and the features learned by the two networks were adopted for classification. The experimental results show that, the ILBPSDNet proposed had certain recognition abilities in many character data sets, and the network parameters and computation were also reduced. Therefore, it has a significant effect in realizing the application of real‐time character recognition. Finally, compared with other latest networks, its network performance could be maintained at a certain level.
Unsupervised many‐to‐many image‐to‐image translation across multiple domains
Authors: Lin Ye , Fu Keren , Ling Shenggui , Cheng Peng 
Published: April 2021

AbstractUnsupervised multi‐domain image‐to‐image translation aims to synthesize images among multiple domains without labelled data, which is more general and complicated than one‐to‐one image mapping. However, existing methods mainly focus on reducing the large costs of modelling and do not pay enough attention to the quality of generated images. In some target domains, their translation results may not be expected or even cause the model collapse. To improve the image quality, an effective many‐to‐many mapping framework for unsupervised multi‐domain image‐to‐image translation is proposed. There are two key aspects to the proposed method. The first is a many‐to‐many architecture with only one domain‐shared encoder and several domain‐specialized decoders to effectively and simultaneously translate images across multiple domains. The second is two proposed constraints extended from one‐to‐one mappings to further help improve the generation. All the evaluations demonstrate that the proposed framework is superior to existing methods and provides an effective solution for multi‐domain image‐to‐image translation.
Detail texture detection based on Yolov4‐tiny combined with attention mechanism and bicubic interpolation
Authors: Hui Tian , Xu YueLei , Jarhinbek Rasol 
Published: April 2021

AbstractAero‐engine blades crack detection is one of the important tasks in daily ground maintenance, crack is a kind of texture feature, due to the random distribution, irregular shape and vague characteristics, which is still a challenging task to realize automatic detection in working environment. A detection model based on the Yolov4‐tiny is proposed that is universal and focuses more on the characteristics of cracks, and it is implemented in embedded device. First, in order to distinguish the cracks and noises, an improved attention module is introduced into the backbone of Yolov4‐tiny to enhance the model's capability to focus on crack areas; second, in order to improve the effect of multi‐scale feature fusion, the bicubic interpolation is implemented in upsampling module; finally, in order to solve the redundant detection results of bounding‐boxes in crack areas, the optimized non‐maximum suppression method is proposed to make the detection results better corresponding to the groundTruth. The robustness of proposed detection model was demonstrated by evaluating varying lighting and noise images. The average precision on integrated datasets is 81.6%, which outperforms the original Yolov4‐tiny by an increase of 12.3%.
Investigation of numerical dispersion with time step of the FDTD methods: avoiding erroneous conclusions
Authors: Cheng Yu , Chen Guangzhi , Wang Xiang‐Hua , Yang Shunchuan 
Published: April 2021

AbstractTo obtain high accuracy and efficiency in the simulations, an optimum time step should be taken in finite‐difference time‐domain (FDTD) methods. The authors investigated how time steps impact on numerical dispersion of two FDTD methods including the FDTD(2,2) method and the FDTD(2,4) method. Through rigorously analytical and numerical analysis, it is found that small time steps of the FDTD methods do not always have small numerical errors. Our findings reveal that these two FDTD methods present different behaviours with respect to time steps: (1) for the FDTD(2,2) method, smaller time steps limited by the Courant‐Friedrichs‐Lewy condition increase numerical dispersion and lead to larger simulation errors and (2) for the FDTD(2,4) method, as the time step increases, numerical dispersion errors first decrease and then increase. Our findings are also comprehensively validated from one‐ to three‐dimensional cases through several numerical examples including wave propagation, resonant frequencies of cavities and a practical engineering problem.
Plane wave scattering from thin dielectric disk in free space: Generalized boundary conditions, regularizing Galerkin technique and whispering gallery mode resonances
Authors: Lucido Mario , Balaban Mykhaylo V. , Nosich Alexander I. 
Published: April 2021

AbstractConsidered is the plane‐wave scattering from and absorption by a thin circular dielectric disk. The analysis uses a set of the singular integral equations for the effective electric and magnetic currents, derived using the generalized boundary conditions on the disk median section. Following the recently developed analytical preconditioning procedure, these equations are discretized by the Galerkin technique with judiciously chosen expansion functions, which provide for the Fredholm second‐kind nature of the resulting matrix equations. This guarantees the code convergence and high efficiency. It is demonstrated that the developed technique delivers the most important features of thin dielectric disks–the resonances on the natural modes. In the resonances on the slab modes, the disk can be well‐transparent and the shadow is created only by its rim; in the whispering gallery mode resonances, the scattering occurs mainly in the disk plane.
The rigorous solution of the scattering problem for a finite cone embedded in a dielectric sphere surrounded by the dielectric medium
Authors: Kuryliak Dozyslav B. 
Published: April 2021

AbstractWave scattering from a finite hollow cone with perfectly conducting boundaries embedded in a dielectric sphere is considered. The structure is excited axially symmetrically by the radial electric dipole. The scattering problem is formulated in the spherical coordinate system as the boundary value problem for the Helmholtz equation. The diffracted field is given by expansion in the series of eigenfunctions. Owing to the enforcement of the conditions of continuity together with the orthogonality properties of the Legendre functions the diffraction problem is reduced to infinite system of linear algebraic equations (ISLAE) of the first kind. The usage of the analytical regularization approach transforms the ISLAE of the first kind to the second one and allows one to justify the truncation method for obtaining the numerical solution in the required class of sequences. This system is proved to be regularized by a pair of operators, which consist of the convolution type operator and the corresponding inverse one. The inverse operator is found analytically using the factorization technique. The numerical examples are presented. The static and the low‐frequency approximations as well as the transition to the limiting case when the cone degenerates into the disc are considered.
Enhancement of the correlation of the photons of thermal light
Authors: Khokhlov D.L. 
Published: April 2021

AbstractThe scheme of the arrangement of five 50/50 non‐polarizing beam splitters is considered. It may provide for the enhancement of the correlation of the photons of thermal light up to 75%. The correlation of the photons after the arrangement can be measured using ghost imaging, Bell test, Hong‐Ou‐Mandel interference.
Using QKD in MACsec for secure Ethernet networks
Authors: Cho Joo Yeon , Sergeev Andrew 
Published: April 2021

AbstractMedia access control security (MACsec) is an IEEE 802.1AE standard for secure communication on Ethernet links. MACsec ensures the confidentiality, integrity and origin authenticity of Ethernet frames. The secrecy of MACsec stems from a root key that is either configured as a pre‐shared key or derived from a mutual authentication protocol. However, both methods are not ideal because such a root key may be disclosed due to human errors or broken by quantum attacks. Here, the authors investigate the quantum key distribution (QKD) as an alternative source of trust for MACsec. QKD can be used as either a root key provider or a session key generator. The authors develop a new key exchange protocol based on QKD for Ethernet networks. Furthermore, it is verified by the experiment that QKD could be well integrated into MACsec without performance degradation.
Stockwell‐transform and random‐forest based double‐terminal fault diagnosis method for offshore wind farm transmission line
Authors: Wang Xiaodong , Gao Xing , Liu Yingming , Wang Yonghao 
Published: April 2021

AbstractDue to the difficulty and time‐consumption in locating short‐distance transmission lines for deep‐sea offshore wind farm (DOWF)，this paper proposes a novel double‐terminal fault location method by using Stockwell‐transform (ST) and random‐forest (RF). After the fault type and branch are accurately determined, the accurate transmission line fault location is located. Firstly, Stockwell‐transform is employed to extract fault eigenvalues from the collected wind turbine (WT) current signals, which will reduce the sensitivity of eigenvalues to noise. And the Pearson correlation coefficient (PCC) is introduced to remove duplicate eigenvalues. Secondly, the reserved fault eigenvalues are taken as inputs to the different random‐forest to classify fault types and identify the fault branch, respectively. Finally, the double‐terminal fault location principle is established in fault negative sequence network (only ABCG uses positive sequence components). Newton‐Raphson method (NRM) is used to eliminate the influence of asynchrony data, which implies an accurate transmission line fault location for deep‐sea offshore wind farm. More than 4000 fault cases data obtained by Simulink simulation verify the feasibility and performance of the proposed method. The results show that the proposed location method has a high fault recognition rate and is immune to fault inception angle, resistance, location and noise.
Vector control strategy for motor‐generator pair drive inverters in parallel operation
Authors: Li Chenyang , Huang Yongzhang , Guan Fei , Fu Wenqi , Wu Qianyu 
Published: April 2021

AbstractIn view of the weak moment of inertia for power system with high penetration of renewable energy and limited transient voltage support of power electronics, a synchronous motor‐generator pair (MGP) is proposed as a possible solution for renewable energy integration to improve grid stability. In order to realize the large‐scale renewable energy integration, parallel inverters drive MGP is an ideal control scheme. Firstly, the working principle and mathematical model of MGP are introduced. Then based on a comparative analysis of control of parallel inverters and torque control of synchronous motors, the decoupling vector control method of MGP is proposed. Considering the linear relation between q‐axis current and the active power in the rotor flux‐oriented mode, the strategy of parallel drive for MGP with vector control is established. Different control loop for off‐grid and grid‐connected operation is designed, and effectiveness of this control strategy is verified by simulation. Finally, a 5 kW MGP experimental platform with dual inverters is built, the parameters are selected to test stability of the system, and power distribution and efficiency are studied. The results indicate that the parallel operation of MGP is stable under dynamic conditions, the strategy can realize the independent control of each inverter.
Theoretical investigation on an oscillating buoy WEC‐floating breakwater integrated system
Authors: Ning Dezhi , Guo Baoming , Wang Rongquan , Lin Lin 
Published: April 2021

AbstractBased on the concept of cost sharing, an oscillating buoy wave energy converter‐ floating breakwater integrated system is proposed, in which the surge or pitch motion of the front‐pontoon equipped with Power Take‐off (PTO) system is allowed. In this study, the methods of eigenfunction matching and variables separation are applied to establish a theoretical model on hydrodynamic performance of the proposed integrated system. Under the condition of optimal PTO damping, the effects of the front‐pontoon width, draft and pontoon spacing on the capture width ratio, reflection coefficient and transmission coefficient are investigated, respectively. It is found that the integrated system with surging front‐pontoon performs better on the wave energy conversion than that with pitching one, especially in the high frequency region. The peaks of capture width ratio Cw are associated with the gap resonance and the increase of front‐pontoon motion induced by the ‘hydrodynamic constructive effect’.
IRCI‐free multiple subband MIMO SAR
Authors: AlShaya Mohammed , Yaghoobi Mehrdad , Mulgrew Bernard 
Published: April 2021

AbstractAn inter‐range cell interference (IRCI)‐free multiple subband multiple‐input multiple‐output (MIMO) synthetic aperture radar (SAR) algorithm is proposed to obtain a high‐resolution wide swath (HRWS) imaging. The received signals of the proposed configuration are formulated as multiple‐input single‐output (MISO) system identification problems using the principle of the displaced phase centre in a way that all the subband waveforms are processed simultaneously without the need to separate them at the receiver. This would maximise the bandwidth utilisation efficiency. The channel impulse response in the range dimension is identified using a frequency domain system identification‐‐based estimation algorithm, which is free from IRCI, instead of using conventional matched filters. A pulse repetition frequency lower than the Doppler bandwidth is used to obtain the HRWS imaging, and the resulted azimuth ambiguity is removed using a set of spatial filters applied on the received signals formulated as separate MISO system identification problems. Finally, both simulated and constructed raw data are used to validate the efficiency of the proposed algorithm.
Bifurcation analyses and potential landscapes of a cortex–basal ganglia–thalamus model
Authors: Yan Chenri , Liu Quansheng , Bi Yuanhong 
Published: April 2021

AbstractThe dynamics of cortical neuronal activity plays important roles in controlling body movement and is regulated by connection weights between neurons in a cortex–basal ganglia–thalamus (BGCT) loop. Beta‐band oscillation of cortical activity is closely associated with the movement disorder of Parkinson's disease, which is caused by an imbalance in the connection weights of direct and indirect pathways in the BGCT loop. In this study, the authors investigate how the dynamics of cortical activity are modulated by connection weights of direct and indirect pathways in the BGCT loop under low dopamine levels through bifurcation analyses and potential landscapes. The results reveal that cortical activity displays rich dynamics under different connection weights, including one, two, or three stable steady states, one or two stable limit cycles, and the coexistence of one stable limit cycle with one stable steady state or two stable ones. For a low dopamine level, cortical activity exhibits oscillation for larger connection weights of direct and indirect pathways. The stability of these stable dynamics is explored by the potential landscapes.
Role of Transperineal Ultrasound (TPUS) in Children with Ambiguous Genitalia
Authors: Rangarajan Krithika , Jana Manisha , Wadgera Nagesh , Gupta Arun Kumar , Bajpai Minu , Kandasamy Devasenathipathy 
Published: April 2021

Abstract
Objectives Accurate delineation of anatomy in children with ambiguous genitalia early in life is important. This commonly involves conventional fluoroscopic genitogram (traumatic to the child) and magnetic resonance imaging (MRI) examination (involves sedation). In this study, our objectives were twofold: (1) to describe the findings on transperineal ultrasound (TPUS) in normal children and (2) to describe the findings on TPUS in children with ambiguous genitalia and correlate them with conventional genitogram.
Materials and Methods TPUS was prospectively performed in 10 children without genital ambiguity (5 girls and 5 boys). Subsequently, 15 consecutive children having disorders of sex differentiation (DSDs) with genital ambiguity underwent TPUS. The presence or absence of müllerian structures was documented. Of these patients, 14 also underwent conventional genitogram as a part of routine evaluation. The gold standard was established either by comparison with surgical findings (in patients who underwent surgery) or by comparison with a combination of findings on genitogram and transabdominal ultrasound in patients who did not undergo surgery.
Results In all normal children, lower urogenital tracts could be clearly delineated on TPUS. Out of the 15 children with ambiguous genitalia, TPUS could establish the presence/absence of müllerian structures in 14. This was concordant with findings on conventional genitogram/surgery. In one patient, müllerian structure was missed on TPUS but demonstrated on genitogram. In two children, TPUS showed the müllerian structure, which was not seen on genitogram. When both the controls and the cases were combined, TPUS had an accuracy of 95% and specificity of 100% in the detection of müllerian structures.
Conclusion TPUS is feasible and accurate in demonstration of lower urogenital tract anatomy in children with DSDs having ambiguous genitalia. It can be performed without sedation, and is suitable for use as a screening modality in children with ambiguous genitalia.
The Effect of Acute Beetroot Juice Supplementation After Strenuous Physical Activity on Creatine Kinase Levels
Authors: Sinaga F A , Sinaga R N , Manalu N 
Published: April 2021

Abstract
Strenuous physical activity can cause muscle damage which is marked by an increase in creatine kinase levels. One of the strategies to prevent muscle damage is to consume antioxidants and anti-inflammatory. Beetroot (Beta vulgaris L.) is known to have antioxidant and anti-inflammatory activity. The aim of this study was to determine the effect of acutely giving beetroot juice on creatine kinase levels after strenuous physical activity. The research sample used 20 trained males. The sample was divided into two groups (Experiment = 10; Placebo = 10). The pre-test was done by checking creatine kinase levels before engaging in strenuous physical activity. After doing strenuous physical activity by running on a treadmill with an intensity of 90-100% for 30 minutes, the experimental group was given 300 ml of beetroot juice (BRJ) every day for 3 days, while the control group was given a placebo drink. Creatine kinase levels were measured immediately, 24 hours, 48 hours, and 72 hours after strenuous physical activity. The results showed that CK levels decreased significantly 24 hours, 48 hours and 72 hours after strenuous physical activity in the BRJ group compared to the placebo group (p <0.05) The conclusion of this study is that giving BRJ acutely after doing strenuous physical activity can reduce creatine kinase levels in trained male athletes. Acute JBR supplementation in this study can help reduce muscle damage due to strenuous physical exercise through nutritional interventions
Medium chain fatty acids: extraction, isolation, purification, bioactive properties and application
Authors: Chen Yuwei , She Yongbo , Lei Jing , Wang Dongning , Wu Songwen , Men Ke 
Published: April 2021

Abstract
Compared with long-chain fatty acids, medium-chain fatty acids are characterized by fast digestion and absorption, less fat accumulation and deposition, improve insulin resistance, regulate energy metabolism, inhibit microorganisms and other biological functions. They are widely used in food, medicine, genetic engineering and other nutrition-related aspects, and have great potential in the development and utilization of health food. In this paper, the definition, source, physicochemical properties, metabolic characteristics, biological functions, safety and application in nutrition-related fields of medium chain fatty acids will be reviewed and discussed.