bluuebunny/crossref_metadata_2025 huggingface dataset:
Imperfect Debugging-Based Modeling of Fault Detection and Correction Using Statistical Methods
Authors: Tiwari Asheesh , Sharma Ashish
Published: January 2021

With the current advancement of technology, real-time software has been extensively utilized in several complex systems. The eternally rising complexity of software formulates it exceptionally hard to maintain the reliability of software and has strained extraordinary awareness in software industries. Nearly all reliability-based software reliability growth models (SRGMs) are formulated using a general consideration that during the testing phase, all detected faults are instantly corrected without introducing any new fault. Therefore, both detection and correction of faults are considered as similar processes. In this paper, inclusive modeling is done for investigating the detection and correction of faults under an imperfect debugging scenario. This formulation is modeled by considering the postulation that new faults are involved throughout the correction of a hard type of fault. Numerous qualitative measures for assessment of reliability are considered and least square estimations of unidentified model parameters are assessed. The validation of the derived proposed models is verified through actual datasets. The measures of accuracy are the mean square error (MSE), root mean square error (RMSE), bias, variance and root mean square prediction error (RMSPE) are calculated employing valid datasets. The goodness of fit criteria is verified based on such qualitative measures.
Access Control Policy Maintenance in IoT Based on Machine Learning
Authors: Zhao Yinyan , Su Mang , Wan Jie , Hou Jinpeng , Mei Dong
Published: January 2021

The rapid growth of communication networking, ubiquitous sensing, and signal processing, has promoted the development of the Internet of Things (IoT). However, the IoT is essentially dynamic and has no clearly defined network boundary, unauthorized access and data leakage may be much easier. Attribute-based access control (ABAC) can solve the problem of fine-grained access control and large-scale user dynamic expansion in complex information systems, and provides an ideal access control solution for an open network environment, which is more suitable for the dynamic access environment of IoT. However, the dynamic nature of IoT brings new challenges to access control. On the one hand, as new devices and services are continuously deployed, administrators need to manually formulate new rules, which is time-consuming and error-prone. On the other hand, as the IoT environment is continuously changing, the access policy easily becomes unsuitable for the current environment. In order to solve the above two problems, we propose a new scheme named Policy Maintenance-based machine learning (PMML), which includes two modules named Policy Generalization (PG) and Policy Evaluation (PE). After the access control model is deployed, automated PG and PE are carried out to maintain the rule set. In the PG module, we define a novel measure, resource similarity, and integrate it into policy mining so that policies could generalize among related resources. In the PE module, we introduce a quantitative method to assess rules and prune rules of low-quality. We conduct our experiments on real-world enterprise access logs from Amazon, and thoroughly analyzed the effects of different hyper-parameters on the experimental results. The experimental results have qualitatively and quantitatively shown the effectiveness of our proposed scheme.
Design and Performance of High-Speed Energy-Efficient CMOS Double Tail Dynamic Latch Comparator Using GACOBA Load Suitable for Low Voltage Applications
Authors: Varshney Vikrant , Dubey Avaneesh K. , Nagaria R. K.
Published: January 2021

The need of energy-efficient, high-speed, and low-offset analog-to-digital converters is forcing to design the dynamic latch comparators to enhance the speed and energy efficiency with minimum offset. This paper presents a novel double tail dynamic latch comparator using bulk-driven process and common-gate (CG) amplifier in amplification stage. The gain of amplification stage is enhanced using GACOBA load in which gain is controlled by bulk amplification through CG amplifier. It results in remarkable enhancement in regeneration speed and reduction in power consumption. The analytical expressions of delay and offset due to mismatch are also derived. These derivations explore the key contributors to reduce the delay and offset of proposed comparator. The outcomes are verified in CADENCE SPECTRE at 45-nm CMOS process technology through various simulations and Monte-Carlo analysis at different process corners. The post-layout analysis validates the simulation results. The proposed comparator is 93% more energy-efficient and lessens more than 84% delay in comparison of conventional design. The 1–[Formula: see text] input offset voltage and average input voltage error due to kickback noise are 2.48[Formula: see text]mV and 0.824[Formula: see text][Formula: see text]V, respectively at 0.8[Formula: see text]V power supply with 34.32[Formula: see text][Formula: see text]m2 active area.
High-Q, High-Rejection Ratio Complex Second-Order Charge-Sampling Switched gm-C Semi-Passive Band-Pass Filter
Authors: Jafari Mohammad Shayan , Jannesari Abumoslem
Published: January 2021

In this paper, a complex second-order charge-sampling switched [Formula: see text]-[Formula: see text] semi-passive band-pass filter (BPF) is presented which by using the technique of increasing the number of input signal phases without the need to increase the number of clock phases and switches, has been improved out-of-band rejection, near-band rejection and the quality factor of the filter. In addition to the tunable bandwidth and center frequency that can be tuned independently, the proposed filter provides a very high linearity and consumes low power. Designed and simulated in a [Formula: see text]m standard CMOS technology, this filter operating at 1[Formula: see text]GS/s sampling rate has an adjustable center frequency of 11.68–28.5[Formula: see text]MHz and a tunable bandwidth of 1.8–8.74[Formula: see text]MHz. Also, the out-of-band rejection varies from 37[Formula: see text]dB to 39[Formula: see text]dB in an offset frequency of 3 fc. The in-band IIP3, power consumption and input-referred noise are 28[Formula: see text]dBm, 5[Formula: see text]mW and 13.8–18.8[Formula: see text]nv/sqrt (Hz), respectively
Physics of superluminous supernovae
Authors: Chen Ke-Jung
Published: January 2021

Understanding how massive stars die as supernovae (SNe) is a crucial question in modern astrophysics. SNe are powerful stellar explosions and key drivers in the cosmic baryonic cycles by injecting their explosion energy and heavy elements to the interstellar medium that forms new stars. After decades of effort, astrophysicists have built up a stand model for the explosion mechanism of massive stars. However, this model is challenged by new kinds of stellar explosions discovered in the recent transit surveys. In particular, the new population called superluminous SNe, which are a hundred times brighter than typical SNe, is revolutionizing our understanding of SNe. New studies suggest the superluminous SNe are associated with the unusual demise of very massive stars and their extreme SNe powered by the radioactive isotopes or compact objects formed after the explosion. Studying these SNe fills a gap of knowledge between the death of massive stars and their explosions; furthermore, we may apply their intense luminosity to light up the distant universe. This paper aims to provide a timely review of superluminous SNe physics, focusing on the latest development of their theoretical models.
Extension of Verlinde gravity formalism to nonspherically symmetric mass distributions
Authors: Yoon Youngsub
Published: January 2021

We extend Verlinde gravity formalism to nonspherically symmetric case and apply it to calculate the gravitational acceleration near, but above the surface of Earth. We predict the violation of equivalence principle, and obtain [Formula: see text] for gold and aluminum, which agrees with [Formula: see text] obtained by an experiment conducted in 1964. We also obtained [Formula: see text] for beryllium and titanium, which agrees with [Formula: see text] obtained by an experiment conducted in 2007. Finally, we suggest that this experiment in 2007 be repeated with beryllium or titanium replaced by silver or gold, which would make [Formula: see text] enough big to confirm the violation of the equivalence principle.
Refining the general comparison theorem for the Klein–Gordon equation
Authors: Hall Richard L. , Harb Hassan
Published: January 2021

By recasting the Klein–Gordon equation as an eigen-equation in the coupling parameter [Formula: see text] the basic Klein–Gordon comparison theorem may be written [Formula: see text], where [Formula: see text] and [Formula: see text] are the monotone nondecreasing shapes of two central potentials [Formula: see text] and [Formula: see text] on [Formula: see text]. Meanwhile, [Formula: see text] and [Formula: see text] are the corresponding coupling parameters that are functions of the energy [Formula: see text]. We weaken the sufficient condition for the ground-state spectral ordering by proving (for example in [Formula: see text] dimension) that if [Formula: see text], the couplings remain ordered [Formula: see text], where [Formula: see text] and [Formula: see text] are the ground-states corresponding, respectively to the couplings [Formula: see text] for a given [Formula: see text]. This result is extended to spherically symmetric radial potentials in [Formula: see text] dimensions.
Charged particle production in pp collisions at s = 8, 7 and 2.76 TeV at the LHC-a case study
Authors: Aggarwal R. , Kaur M.
Published: January 2021

We analyze the charged-particle multiplicity distributions measured by the ALICE experiment, over a wide pseudorapidity range, for [Formula: see text] collisions at [Formula: see text], 7 and 2.76 TeV at the LHC. The analysis offers an understanding of particle production in high energy collisions in the purview of a new distribution, the shifted Gompertz distribution. Data are compared with the distribution and moments of the distributions are calculated. A modified version of the distribution is also proposed and used to improve the description of the data consisting of two different event classes: the inelastic and the nonsingle diffractive and their subsets in different windows of pseudorapidity, [Formula: see text]. The distribution used to analyze the data has a wide range of applicability to processes in different fields and complements the analysis done by the ALICE collaboration in terms of various LHC event generators and IP-Glasma calculations.
FRACTAL CHARACTERIZATION AND MECHANICAL BEHAVIOR OF PILE–SOIL INTERFACE SUBJECTED TO SULFURIC ACID
Authors: XIAO JIE , QU WENJUN , JIANG HAIBO , LI LONG , HUANG JUAN , CHEN LIN
Published: January 2021

This study aimed to investigate the different performance of pile–soil interfaces when the concrete was subjected to sulfuric acid corrosion. A series of large-scale direct shear tests were carried out to study the influence of sulfuric acid corrosion on the interface between soil and concrete pile. Concrete specimens immersed in sulfuric acid solution for different durations (0, 31, 93 and 154 days) were used to simulate the concrete pile surface roughness under sulfuric acid environment, which would be more realistic than the artificially roughened surfaces. Sand was used to simulate the soil. Geometric models of concrete specimens attacked by sulfuric acid were captured using a 3D laser scanning technology, and fractal dimension was adopted to evaluate the surface characterization of concrete subjected to sulfuric acid. The shear stress–displacement curves of the interface between sand and corroded concrete were measured. The shear strength parameters and the Clough–Duncan hyperbolic model parameters were obtained. The relationship between friction angle and fractal dimension was established. The results of the tests showed that with the increase of the corrosion duration, the concrete surface became rougher, the fractal dimensions of concrete surface, the sand-corroded concrete interface friction angle, and the shear displacement at peak stress became larger. A nonlinear relationship was found between the fractal dimension and interface friction angle. The results could provide a reference to diagnose, evaluate, and analyze the interface behavior between sulfuric acid corroded concrete materials and soil.
TECHNOLOGY AND APPLICATIONS OF GRAPHENE OXIDE MEMBRANES
Authors: LENG XUANYE , CHEN SIYU , YANG KOU , CHEN MUSEN , SHAKER MAJID , VDOVIN EVGENII E. , GE QI , NOVOSELOV KOSTYA S. , ANDREEVA DARIA V.
Published: January 2021

Graphene oxide (GO) is an amphiphilic, water dispersible, chemical derivative of graphene. Widely used as a pathway to obtain graphene, it also has a number of interesting applications by itself due to its ability to form covalently and non-covalently bonded organic–inorganic hybrids and polymer composites. Thus, GO-based composites are used in numerous applications in membrane and coating technologies. It is important that due to the presence of functional acidic groups, GO possesses tunable physicochemical properties like a negatively charged polyelectrolyte and can be used as stimuli responsive membranes, membranes that can interact with environment and switch their properties on demand. Thus, ionic/molecular separation, water purification, selective sensing, and stimuli responsive properties have already been demonstrated in the laboratory. Good mechanical strength and conductivity (in its partially reduced form) make it attractive for the construction of the membranes for energy devices and sensors. However, concentration and distribution of the functional groups on GO molecules is difficult to control. It makes GO materials difficult to standardize, produce, and apply in industry. To this end, it is important to highlight recent achievement in the synthesis of GO as well as in design of GO-based energy devices, corrosion inhibiting coatings, and biomedical devices with improved working performances to evoke interest on mass production of GO with improved formulation.
INTRODUCTION TO TWO-DIMENSIONAL MATERIALS
Authors: LENG XUANYE , CHEN SIYU , YANG KOU , CHEN MUSEN , SHAKER MAJID , VDOVIN EVGENII E. , GE QI , NOVOSELOV KOSTYA S. , ANDREEVA DARIA V.
Published: January 2021

The application areas of two-dimensional (2D) materials, their heterostructures and composites are rapidly expanding — thanks to their extraordinary mechanical, optical, electronic and thermal properties. The family of 2D materials, which are finding a use in applications, is rapidly growing, and now includes graphene, graphene oxide, hexagonal boron nitride and transition-metal dichalcogenide, as well as the recently obtained chemical derivatives, physically modified hybrids and allotropes. New applications also trigger the development of new and more efficient methods for the synthesis of 2D materials and the formulation of composites. In this paper, we focus on the relation between the structure of the 2D materials and their heterostructures on the one hand and their properties on the other, summarize recent improvements in the synthesis approaches and discuss the perspectives in applications. We highlight existing applications in electronics, optoelectronics, electrocatalysis and energy storage and discuss new potential areas such as functional coatings and biomedical materials and devices.
GREEN SYNTHESIS OF Cu, Ni AND CuNi ALLOY NANOPARTICLES USINGROSMARINUS OFFICINALISPLANT EXTRACT: EVALUATION OF ELECTROCATALYTIC ACTIVITY OF CORRESPONDING METALLIC OXIDES
Authors: AIT ABDESSELAM DYHIA , AITOUT RAZIKA , ZAABAR AIDA , OUKIL DEHBIA , MAKHLOUFI LAID
Published: January 2021

Uric acid (UA) detection is extremely necessary in both blood serum and urine. High UA concentration in blood serum may induce several diseases. It is very important to develop new methods based on their ecofriendly nature for synthesis new materials used in the detection of UA for diagnosing both hyperuricemia and hypouricemia. This study aimed to synthesis copper, nickel, and copper nickel alloy nanoparticles (NPs) by green voice using Rosmarinus officinalis plant aqueous extract at room temperature. Reduction to CuNPs, NiNPs, and CuNi alloy NPs was confirmed by UV-Vis analysis. The IR analysis is used to identify the chemical group present on the synthesized NPs. Scanning electron microscopy (SEM) shows nearly spherical shape of NPs, X Ray diffraction (XRD) pattern shows face cubic center (fcc) structure and the crystallite range size was estimated to be about 19–49[Formula: see text]nm. Then, the synthesized NPs were calcined at 500∘C and characterized by XRD witch confirmed the presence of NPs oxide. These oxidized NPs were used as catalysts to modify carbon paste electrode (CPE) in the study of the electrocatalytic determination of UA by using cyclic voltammetry technique. The result showed that the modified electrodes CPE with 10%CuO, 5%NiO, and 10%CuNiO alloy present the better electrocatalytic activity than uncalcined NPs modified electrodes toward the UA oxidation in phosphate buffer ([Formula: see text]), and exhibited oxidation potential peaks at 515, 541, and 481[Formula: see text]mV[Formula: see text], respectively. The 10%CuNiO/CPE electrode gives a good sensitivity (17.58[Formula: see text][Formula: see text] A[Formula: see text]mM[Formula: see text]) towards UA oxidation compared with the 10%CuO/CPE (6.83[Formula: see text][Formula: see text] A[Formula: see text]mM[Formula: see text] and 5%NiO/CPE (10.74[Formula: see text][Formula: see text]A[Formula: see text]mM[Formula: see text]) electrodes. The detection limits were found to be equal to 100, 100, and 50[Formula: see text][Formula: see text] M for 10%CuO/CPE, 5%NiO/CPE, and 10%CuNiO/CPE, respectively, in awide range of UA concentration. These electrodes also exhibited a high selectivity towards UA in the presence of other interference as well as can be applied for the detection of UA in human urine.
A NEW APPROACH TO PREPARE POLYCRYSTALLINE PbTe–TeO THIN FILM, AND ITS OPTICAL, STRUCTURAL, SURFACE AND ELECTRICAL CHARACTERIZATION
Authors: TEZEL FATMA MEYDANERI , KARIPER İ. AFŞIN
Published: January 2021

In this study, PbTe thin film was produced on glass substrates, via chemical bath deposition (CBD) method, with 3-h deposition time at 50∘C. The produced thin film had polycrystalline structure; TeO2, PbTe, PbTe3 and Te2O5 crystals that were characterized by X-ray diffraction (XRD) had tetragonal, cubic, tetragonal and monoclinic crystal structures, respectively. Reflectivity ([Formula: see text]; in %), optical transmission ([Formula: see text]; in %), optical bandgap ([Formula: see text], absorption, dielectric constant ([Formula: see text], extinction coefficient ([Formula: see text] and refractive index ([Formula: see text] of polycrystalline PbTe thin film obtained using UV–Vis spectrophotometer were 29.87%, 19.41%, 3.30[Formula: see text]eV, 0.6, 3.72, 0.05 and 4.08, respectively. Grain sizes of polycrystalline PbTe thin film varied between 8.79[Formula: see text]nm and 52.55[Formula: see text]nm. Optical and electrical conductivities of the crystals according to photon energy were calculated using optical parameters, whereas their surface morphology was characterized by scanning electron microscopy (SEM). The thickness of polycrystalline PbTe thin film was measured by atomic force microscopy (AFM), and found to be 900[Formula: see text]nm.
Trait-Augmented Games with Limited-Skill Agents
Authors: Gmeiner Michael , Lambson Val
Published: January 2021

We present a framework populated by limited-skill agents whose cognitive abilities fall short of full rationality in two ways. First, the agents are incapable of considering all of the available actions. Second, they do not perceive the actions directly, but only view traits that are related to the actions’ identities. We define skill in terms of the number of action-trait pairs an agent can consider: agents with higher skill can consider more pairs. Limited-skill agents can be grafted into many contexts. We first discuss trends in how agents select which action-trait pairs to view when maximizing expected payoff. We then present two applications: the relationship between skill and expected payoff and product differentiation.
On weakly ℋC-embedded subgroups and p-nilpotence of finite groups
Authors: Ramadan M.
Published: January 2021

Let [Formula: see text] be a finite group and [Formula: see text] a subgroup of [Formula: see text]. We say that [Formula: see text] is an [Formula: see text]-subgroup of [Formula: see text] if [Formula: see text] for all [Formula: see text]; [Formula: see text] is called weakly [Formula: see text]-embedded in [Formula: see text] if [Formula: see text] has a normal subgroup [Formula: see text] such that [Formula: see text] and [Formula: see text] for all [Formula: see text] where [Formula: see text] is the normal closure of [Formula: see text] in [Formula: see text]. In this paper, we study the [Formula: see text]-nilpotence of a group [Formula: see text] in which every subgroup of order [Formula: see text] of a Sylow [Formula: see text]-subgroup [Formula: see text] with [Formula: see text] is weakly [Formula: see text]-embedded in [Formula: see text]. Many recent results in the literature related to [Formula: see text]-nilpotence of [Formula: see text] are generalized.
Simpson’s Rule Revisited
Authors: Simić Slavko , Bin-Mohsin Bandar
Published: January 2021

In this paper, we give some refinements of Simpson’s rule in cases when it is not applicable in its classical form i.e., when the target function is not four times differentiable on a given interval. Some sharp two-sided inequalities for an extended form of Simpson’s rule are also proven.
A Cell-Based Smoothed Finite Element Method for Arbitrary Polygonal Element to Solve Incompressible Laminar Flow
Authors: Liu Mingyang , Gao Guangjun , Zhu Huifen , Jiang Chen , Liu Guirong
Published: January 2021

In this paper, a cell-based smoothed finite element method using the arbitrary [Formula: see text]-sided polygonal element (CS-FEM-Poly) is developed to solve fluid mechanics problems. A stabilization method, characteristic-based split coupled with stabilized pressure gradient projection (CBS/SPGP), is employed to deal with numerical oscillations for CS-FEM-Poly. We validate CS-FEM-Poly and test its numerical behaviors using triangular, quadrilateral and polygonal elements on four typical numerical examples. Numerical results show that the CS-FEM-Poly based on CBS/SPGP produces well-agreed solutions with the exact solutions of benchmarks, and gives desirable convergence rate as compared with FEM. In the backward-facing step flow example, the numerical robustness for concave elements is manifested for CS-FEM-Poly. The proposed CS-FEM-Poly exhibits the remarkable potential for polygonal mesh or glued polygonal elements in the hybrid mesh to solve incompressible flows.
Meshless Numerical Simulation of Singular Fields at Crack Tips of Branched Crack
Authors: Bai Yinghua , Tian Ran , Tang Xu , Kong Lin-Hao , Liu Jia-Hui , Nie Fenghua
Published: January 2021

One of the most important tasks in the numerical analysis of the fracture problem is to achieve a high-precision approximation of the singular stress fields at crack tips. Partially or fully enriched basis functions are often used as enhancements on the whole problem domain or just near the crack tips when constructing the meshless shape functions to simulate the singularity fields at crack tips, namely: global enhancement with fully enriched basis, global enhancement with partially enriched basis, local enhancement with fully enriched basis and local enhancement with partially enriched basis. The scheme of the enriched basis has been extensively and successfully employed in handling problems with a single crack, but its applicability in the branched crack problem remains to be studied. In this paper, the stress intensity factors, the displacement field and the stress field near crack tip are calculated by these four schemes, respectively, and the singular field at the crack tip of a branching crack is also considered. The numerical results show that: for the problems with a single crack, the accuracy of the stress intensity factor obtained by the meshless method with different kinds of enriched basis is basically the same, but the accuracy of the crack tip field variables is obviously different; for the problems with branched crack, the accuracy of the stress intensity factors differs depending on the problems.
A Novel Cell-Centered Approach of Upwind Types for Convection Diffusion Equations on General Meshes
Authors: Vu Hung , Du Nguyen Huu , Ong Thanh Hai
Published: January 2021

In this paper, we present novel cell-centered finite element methods for the convection-dominated convection–diffusion problems on the general meshes. The proposed schemes can be constructed from a general mesh by building with a dual mesh and its triangular sub-mesh. Moreover, the schemes are based on piecewise linear functions combined with two upwind techniques on the dual sub-mesh in order to stabilize the numerical solutions and eliminate the spurious oscillations. Through numerical results, two methods are shown to be effective in terms of accuracy, stability and computational cost.
Numerical Simulation of the Convection–Diffusion PDEs on a Sphere with RBF-FD and RBF-QR Methods
Authors: Adil Nazakat , Feng Xinlong , He Yinnian , Xiao Xufeng
Published: January 2021

The aim of this paper is to investigate the application of radial basis function-generated finite difference (RBF-FD) methods for convection–diffusion partial differential equations (PDEs) on a sphere. In the application of RBF-FD method, choosing a reasonable value of shape parameter is important to the computation of PDEs. The work is devoted to the numerical study of the range of near optimal shape parameters for the convection–diffusion equations. Because the RBF-FD Direct method often leads to ill-conditioned problems for small shape parameters, the RBF-QR method is applied locally to overcome the ill-conditioning in the context of RBF-FD mode. Additionally, for convection-dominated problems, it can be found that the results of using central-type stencil present spurious oscillations. Therefore, we propose an upwind RBF-FD (URBF-FD) scheme to overcome the problems, which is well adapted to the problems on the sphere and easy to be implemented. Further numerical results show that the proposed URBF-FD method is stable and effective for convection-dominated PDEs on the sphere.
Discrete dynamical systems over double cross-product Lie groupoids
Authors: Esen Oğul , Sütlü Serkan
Published: January 2021

Discrete Euler–Lagrange equations are studied over double cross product Lie groupoids. As such, a geometric framework for the local analysis of a discrete dynamical system is established. The arguments are elucidated on the local discrete dynamics of a gauge groupoid. The discrete Elroy’s beanie is studied as a physical example.
Canonical equivalence in anisotropic models for higher order theory of gravity
Authors: Debnath Subhra , Sanyal Abhik Kumar
Published: January 2021

Different canonical formalisms for higher order theories lead to different phase-space structures of the Hamiltonian. Canonical equivalence of these Hamiltonians at the classical level does not assure the same in the quantum domain, due to nonlinearity. It has been proved in the isotropic models, that the “Dirac constraint analysis” (after taking care of divergent terms) and “Modified Horowitz Formalism” lead to identical phase-space structure of the Hamiltonian for the gravitational action with curvature squared terms. Here, we extend the same in anisotropic space-time, viz, Bianchi-I, Bianchi-III and Kantowski–Sachs models too. This is a prologue toward canonical quantization.
The matter Lagrangian of an ideal fluid
Authors: Mendoza Sergio , Silva Sarahí
Published: January 2021

We show that the matter Lagrangian of an ideal fluid equals (up to a sign depending on its definition and on the chosen signature of the metric) the total energy density of the fluid, i.e. rest energy density plus internal energy density.
A Comparative Study of Seismic Performance of Steel Framed Buildings with Varied Plan-Asymmetric Properties
Authors: Lin Jui-Liang , Chow Te-Kuang , Li Chao-Hsien , Yeh Yeong-Kae
Published: January 2021

This study looks at the influence of plan-asymmetric properties on seismic performance of steel framed buildings by means of a comparative study. The seismic fragility curves of a symmetrical nine-story steel framed building and three asymmetric-plan buildings, which are the variations of the mentioned symmetrical building, are constructed through incremental dynamic analysis (IDA). The three asymmetric-plan buildings are torsionally stiff (TS), torsionally similarly stiff (TSS), and torsionally flexible (TF) buildings, respectively. The considered plan-asymmetric properties are eccentricity ratio and uncoupled frequency ratio. A comparative study of three damage states (DS) including immediate occupancy (IO), collapse prevention (CP), and global instability (GI) of the four buildings is conducted. The results show that in terms of slight damage, both the symmetrical building and the TSS building perform better. In terms of severe damage and collapse, the symmetrical building obviously outperforms the other three asymmetric-plan buildings. In addition, the TF building always performs the worst regardless of the DSs.
Mechanism Study of Vehicle–Bridge Dynamic Interaction under Near-Fault Ground Motions
Authors: Cui Cunyu , Xu Yan , Zeng Zeng
Published: January 2021

The effect of vehicle on the seismic responses of highway bridge has usually been neglected under the assumption that the possibility of vehicles crossing highway bridge or viaduct with a concurrent earthquake is extremely low. Furthermore, there is no in phase movement of vehicle and bridge was observed in past earthquake events. However, in the heavily trafficked urban area this is probably not the case. The mechanism of vehicle–bridge dynamic interaction still remains unclear. Therefore, an analytical vehicle–bridge model with contact elements is built to study the dynamic interaction and the seismic responses of vehicle–bridge system when subjected to near-fault ground motions. In this vehicle–bridge model, vehicle and highway bridge are coupled through Coulomb friction forces in the horizontal directions and through Hertz impact force in the vertical direction, respectively. The horizontal Coulomb friction forces varying with the variation of vertical Hertz impact force under earthquake excitations. Analysis results reveal that vehicle sometimes has a significant influence on the vertical seismic displacement response of bridge and mass ratio of vehicle to bridge is one of the primary factors governing the effect of vehicle on the seismic responses of bridge. Influence of vehicle frequency and damping ratio on the seismic responses of bridge are both related to mass ratio and become significant with the increasing of mass ratio. However, for the responses of the vehicle itself, influence of vehicle frequency and damping ratio is significant only when the mass ratio is small. Due to the weak coupling of vehicle and bridge in the horizontal directions, horizontal displacements of the vehicle can reach several meters, hence possibly endanger the traveling safety of vehicle on highway bridge.
Finite Element Modeling (FEM) vs. Simplified Force-Based Methods for Rigid Retaining Walls Under Earthquake Excitation
Authors: Annapareddy V. S. Ramakrishna , Pain Anindya
Published: January 2021

The performance of conventional rigid retaining wall under harmonic and transient ground motions is evaluated using three-dimensional finite element (FE) simulations. Rotation of wall about the base is found to be the predominant failure mechanism of the gravity retaining wall under seismic excitation. Earth pressure distribution corresponding to the peak ground acceleration is found to be nonlinear and unique in shape. The earth pressure distribution is strongly related to the rotational movement of the wall. Existing force-based methods for rigid retaining walls overestimated the earth pressure under seismic conditions compared to these numerical simulations.
Doubly slice knots and metabelian obstructions
Authors: Orson Patrick , Powell Mark
Published: January 2021

An [Formula: see text]-dimensional knot [Formula: see text] is called doubly slice if it occurs as the cross section of some unknotted [Formula: see text]-dimensional knot. For every [Formula: see text] it is unknown which knots are doubly slice, and this remains one of the biggest unsolved problems in high-dimensional knot theory. For [Formula: see text], we use signatures coming from [Formula: see text]-cohomology to develop new obstructions for [Formula: see text]-dimensional knots with metabelian knot groups to be doubly slice. For each [Formula: see text], we construct an infinite family of knots on which our obstructions are nonzero, but for which double sliceness is not obstructed by any previously known invariant.
Impact of predation in the spread of an infectious disease with time fractional derivative and social behavior
Authors: Bentout Soufiane , Ghanbari Behzad , Djilali Salih , Guin Lakshmi Narayan
Published: January 2021

The main purpose of this paper is to explore the influence of predation on the spread of a disease developed in the prey population where we assume that the prey has a social behavior. The memory of the prey and the predator measured by the time fractional derivative plays a crucial role in modeling the dynamical response in a predator–prey interaction. This memory can be modeled to articulate the involvement of interacting species by the presence of the time fractional derivative in the considered models. For the purpose of studying the complex dynamics generated by the presence of infection and the time-fractional-derivative we split our study into two cases. The first one is devoted to study the effect of a non-selective hunting on the spread of the disease, where the local stability of the equilibria is investigated. Further the backward bifurcation is obtained concerning basic reproduction rate of the infection. The second case is for explaining the impact of selecting the weakest infected prey on the edge of the herd by a predator on the prevalence of the infection, where the local behavior is scrutinized. Moreover, for the graphical representation part, a numerical simulation scheme has been achieved using the Caputo fractional derivative operator.
Exergy Analysis and Optimization of Natural Gas Liquids Recovery Unit
Authors: Khajehpour Hossein , Norouzi Nima , Shiva Navid , Folourdi Reza Mahmoodi , Bahremani Ehsan Hashemi
Published: January 2021

The Natural Gas Liquids (NGL) recovery unit is one of the processes that requires cooling. The sweetened gas enters this unit after the dehydration stage, and the final product called NGL Product is stored and ready for consumption or export. In this research, the first, one of the NGL units, is simulated with HYSYS software. Three types of processes with different cooling systems are studied using the exergy analysis method. Joule–Thomson’s combination with the expander is selected for its high exergy efficiency, and the exergy efficiency function has been selected as the objective function 1 to optimize this process mathematically based on this study’s findings. The critical term in this objective function is the work of the compressors and turboexpanders in the process. After defining the optimization problem, the problem is optimized by two genetic algorithms and SQP, considering the process constraints and the process’s initial conditions. Finally, using the genetic algorithm’s data application to the simulated process, a 15% increase in the plant’s exergic efficiency was observed.
Evaluating Automated Face Identity-Masking Methods with Human Perception and a Deep Convolutional Neural Network
Authors: Hooge Kimberley D. Orsten , Baragchizadeh Asal , Karnowski Thomas P. , Bolme David S. , Ferrell Regina , Jesudasen Parisa R. , Castillo Carlos D. , O’toole Alice J.
Published: January 2021

Face de-identification (or “masking”) algorithms have been developed in response to the prevalent use of video recordings in public places. We evaluated the success of face identity masking for human perceivers and a deep convolutional neural network (DCNN). Eight de-identification algorithms were applied to videos of drivers’ faces, while they actively operated a motor vehicle. These masks were pre-selected to be applicable to low-quality video and to maintain coarse information about facial actions. Humans studied high-resolution images to learn driver identities and were tested on their recognition of active drivers in low-resolution videos. Faces in the videos were either unmasked or were masked by one of the eight algorithms. When participants were tested immediately after learning (Experiment 1), all masks reduced identification, with six of eight masks reducing identification to extremely poor performance. In a second experiment, two of the most effective masks were tested after a delay of 7 or 28 days. The delay did not further reduce identification of the masked faces. In all masked conditions, participants maintained stringent decision criteria, with low confidence in recognition, further indicating the effectiveness of the masks. Next, the DCNN performed an identity-matching task between high-resolution images and masked videos—a task analogous to that done by humans. The pattern of accuracy for the DCNN mirrored some, but not all, aspects of human performance, highlighting the need to test the effectiveness of identity masking for both humans and machines. The DCNN was also tested on its ability to match identity between masked and unmasked versions of the same video, based only on the face. DCNN performance for the eight masks offers insight into the nature of the information in faces that is coded in these networks.
Comparison of Subjective Methods for Quality Assessment of 3D Graphics in Virtual Reality
Authors: Nehmé Yana , Farrugia Jean-Philippe , Dupont Florent , Callet Patrick Le , Lavoué Guillaume
Published: January 2021

Numerous methodologies for subjective quality assessment exist in the field of image processing. In particular, the Absolute Category Rating with Hidden Reference (ACR-HR), the Double Stimulus Impairment Scale (DSIS), and the Subjective Assessment Methodology for Video Quality (SAMVIQ) are considered three of the most prominent methods for assessing the visual quality of 2D images and videos. Are these methods valid/accurate to evaluate the perceived quality of 3D graphics data? Is the presence of an explicit reference necessary, due to the lack of human prior knowledge on 3D graphics data compared to natural images/videos? To answer these questions, we compare these three subjective methods (ACR-HR, DSIS, and SAMVIQ) on a dataset of high-quality colored 3D models, impaired with various distortions. These subjective experiments were conducted in a virtual reality environment. Our results show differences in the performance of the methods depending on the 3D contents and the types of distortions. We show that DSIS and SAMVIQ outperform ACR-HR in terms of accuracy and point out a stable performance. In regard to the time-effort, DSIS achieves the highest accuracy in the shortest assessment time. Results also yield interesting conclusions on the importance of a reference for judging the quality of 3D graphics. We finally provide recommendations regarding the influence of the number of observers on the accuracy.
Crossing Roads with a Computer-generated Agent
Authors: Jiang Yuanyuan , O'Neal Elizabeth E. , Zhou Shiwen , Plumert Jodie M. , Kearney Joseph K.
Published: January 2021

This study investigated how people coordinate their decisions and actions with a risky or safe computer-generated agent in a humanoid or non-humanoid form and how this experience influences later behavior when acting alone. In Experiment 1, participants first repeatedly crossed continuous traffic in a virtual environment with a humanoid computer-generated agent (Figure 1). Participants were specifically instructed to cross with an agent that was programmed to be either safe (taking only large gaps) or risky (also taking relatively small gaps). Participants then repeatedly crossed the same roadway alone. We found that participants’ experiences with crossing safe vs. risky gaps with an agent persisted in later trials when the participants crossed alone, such that participants accepted tighter gaps if they were previously paired with a risky than a safe agent.  In Experiment 2 (Figure 2), we tested whether experience crossing with a risky or safe non-humanoid object (a floating box) also influenced later behavior when crossing alone. We again found that participants who crossed with the risky object partner took tighter gaps when later crossing alone than those who crossed with the safe object partner. The Discussion focuses on the impact of experiences with virtual agents on perception–action tuning and the potential of using virtual agents for training safe road-crossing behavior.
The transient outward potassium current plays a key role in spiral wave breakup in ventricular tissue
Authors: Landaw Julian , Yuan Xiaoping , Chen Peng-Sheng , Qu Zhilin
Published: January 2021

Spiral wave breakup manifesting as multiple wavelets is a mechanism of ventricular fibrillation. It has been known that spiral wave breakup in cardiac tissue can be caused by a steeply sloped action potential duration restitution curve, a property mainly determined by the recovery of L-type calcium current. Here, we show that the transient outward potassium current ( Ito) is another current that plays a key role in spiral wave breakup, that is, spiral waves can be stable for low and high maximum Ito conductance but breakup occurs for intermediate maximum Ito conductance. Since Ito is present in normal hearts of many species and required for Brugada syndrome, it may play an important role in the spiral wave stability and arrhythmogenesis under both normal condition and Brugada syndrome.
Preclinical techniques to investigate exercise training in vascular pathophysiology
Authors: Sangha Gurneet S. , Goergen Craig J. , Prior Steven J. , Ranadive Sushant M. , Clyne Alisa M.
Published: January 2021

Atherosclerosis is a dynamic process starting with endothelial dysfunction and inflammation and eventually leading to life-threatening arterial plaques. Exercise generally improves endothelial function in a dose-dependent manner by altering hemodynamics, specifically by increased arterial pressure, pulsatility, and shear stress. However, athletes who regularly participate in high-intensity training can develop arterial plaques, suggesting alternative mechanisms through which excessive exercise promotes vascular disease. Understanding the mechanisms that drive atherosclerosis in sedentary versus exercise states may lead to novel rehabilitative methods aimed at improving exercise compliance and physical activity. Preclinical tools, including in vitro cell assays, in vivo animal models, and in silico computational methods, broaden our capabilities to study the mechanisms through which exercise impacts atherogenesis, from molecular maladaptation to vascular remodeling. Here, we describe how preclinical research tools have and can be used to study exercise effects on atherosclerosis. We then propose how advanced bioengineering techniques can be used to address gaps in our current understanding of vascular pathophysiology, including integrating in vitro, in vivo, and in silico studies across multiple tissue systems and size scales. Improving our understanding of the antiatherogenic exercise effects will enable engaging, targeted, and individualized exercise recommendations to promote cardiovascular health rather than treating cardiovascular disease that results from a sedentary lifestyle.
Cafestol Inhibits High‐Glucose‐Induced Cardiac Fibrosis in Cardiac Fibroblasts and Type 1‐Like Diabetic Rats
Authors: Liu Ju-Chi , Chen Po-Yuan , Hao Wen-Rui , Liu Yi-Chung , Lyu Ping-Chiang , Hong Hong-Jye
Published: January 2021

Diabetes is associated with the development of myocardial fibrosis, which is related to various cardiac diseases. Cafestol, one of the active ingredients in coffee, has been reported to exert biological effects. However, whether cafestol can ameliorate diabetes‐induced cardiac fibrosis remains unknown. The aim of this study was to evaluate the effects of cafestol on cardiac fibrosis in high‐glucose‐treated cardiac fibroblasts and streptozocin‐ (STZ‐) induced diabetic rats. Rat cardiac fibroblasts were cultured in high‐glucose (25 mM) media in the absence or presence of cafestol, and the changes in collagen synthesis, transforming growth factor‐β1 (TGF‐β1) production, and related signaling molecules were assessed on the basis of 3H‐proline incorporation, enzyme‐linked immunosorbent assay, and western blotting. Cardiac fibroblasts exposed to high‐glucose conditions exhibited increased collagen synthesis, TGF‐β1 production, and Smad2/3 phosphorylation, and these effects were mitigated by cafestol treatment. Furthermore, cafestol increased the translocation of nuclear factor erythroid 2‐related factor 2 and increased the expression of heme oxygenase‐1. The results of molecular docking analysis suggested a selective interaction of cafestol with Kelch‐like ECH‐associated protein 1. The rats with untreated STZ‐induced diabetes exhibited considerable collagen accumulation, which was ameliorated by cafestol. Moreover, activities of catalase, superoxide dismutase, general matrix metalloproteinase, and reduced glutathione concentration were upregulated, whereas malondialdehyde level was downregulated by treatment with cafestol in rats with cardiac fibrosis. These findings highlight the effects of cafestol, which may be useful in treating diabetes‐related cardiac fibrosis.
Four-Dimensional Semi-Riemannian Szabó Manifolds
Authors: Diallo Abdoul Salam , Gupta Punam
Published: January 2021

In this paper, we prove that the deformed Riemannian extension of any affine Szabó manifold is a Szabó pseudo-Riemannian metric and vice versa. We prove that the Ricci tensor of an affine surface is skew-symmetric and nonzero everywhere if and only if the affine surface is Szabó. We also find the necessary and sufficient condition for the affine Szabó surface to be recurrent. We prove that, for an affine Szabó recurrent surface, the recurrence covector of a recurrence tensor is not locally a gradient.