bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling and Analysis of a Manipulator Joint Driven Through a Worm Gear Transmission
Authors: Mooring B. W. , May D. C. , Schulte M. S.
Published: April 2021

Worm gear transmissions are capable of high velocity ratios as well as redirection of rotation. Both of these features are desirable for some robot geometries. A problem has been encountered in several robot designs, however, where a self excited vibration occurs for some configurations of the manipulator in the joint containing the worm gear. In this work, a system which exhibits this type of undesirable motion is examined. The system consists of a DC servo motor which is used to position a flexible cantilever arm through a worm gear transmission. A nonlinear model is developed to describe the motion of the system. The model is then validated by comparing the predicted response to the observed response of an experimental system. It is demonstrated that the model accurately predicts the onset of the unstable vibration. The model is then linearized and it is shown that the linear model will predict the occurrence of the instability as well.
Transient Torque Produced in Arm Shaft of an Industrial Sewing Machine
Authors: Muramatsu N.
Published: April 2021

This study considered the effects of needle penetrating force, needle thread tightening tension, and pressing force of the presser foot on torque produced in the arm shaft of an industrial sewing machine. The results obtained are as follows.

(1) Penetrating force, especially the initial triangular wave fluctuation, induces noticeable transient vibration in torque.

(2) The torsional natural frequency of the arm shaft of the feed mechanism motion system is more than twice that of the thread take-up lever and needle bar mechanism motion system. Penetrating force, according to the relations with the natural period of the system, is considerably more transient than pressing force.

(3) Consequently, when estimating torque, it is necessary that the arm shaft of the thread take-up lever and needle bar mechanism motion system be considered as elastic. On the other hand, the arm shaft of the feed mechanism motion system can be treated as a rigid body.
Three-Dimensional Dynamic Simulation of Helical Compression Springs
Authors: Lin Y. , Pisano A. P.
Published: April 2021

The dynamic equations for general helical springs are solved and classified according to the number of energy terms used to formulate them. Solutions of several sets of dynamic equations, each with a different number of energy terms, are compared with experimental data. It is found that at higher compression speeds the numerical solution with a traditional, fixed boundary represents a physically impossible situation. A moving boundary technique is applied to improve the numerical solution and bring it into agreement with physical reality. Since a convergence proof for a numerical algorithm for nonlinear partial differential equations with a moving boundary is not available, a grid study has been performed to demonstrate convergence. The agreement between the solutions of different grid sizes and the experimental data is taken to show that the numerical algorithm was convergent. This three dimensional spring simulation model can be used in the simulation of high-speed mechanical machinery utilizing helical springs, and in particular, for design optimization of automotive valve springs.
Solution of Multibody Dynamics Using Natural Factors and Iterative Refinement: Part I — Open Kinematic Loops
Authors: Wehage R. A.
Published: April 2021

An O(n) methodology employing block matrix partitioning and recursive projection to solve multibody equations of motion coupled by a sparse connectivity matrix was developed in (Wehage 1988, 1989, Wehage and Shabana, 1989). These primitive equations, which include all joint generalized and absolute coordinates and constraint reaction forces, are easily obtained from free body diagrams. The corresponding recursive algorithms isolate the generalized joint accelerations for numerical integration and offer the best computational advantage when solving long kinematic chains on serial processors. Recursion, however, precludes effective exploitation of vector or parallel processors. Therefore this paper explores less recursive algorithms by applying the inverse of joint connectivity to eliminate absolute accelerations and constraint forces yielding a generalized system of equations. The resulting positive definite generalized inertia matrix is first represented symbolically as a product of sparse matrices, of which some are singular and then as the product of nonsingular factors obtained recursively. This algorithm has overhead ranging from O(n2) to O(n) depending on the degree of system parallelism. Incorporating iterative refinement and exploiting parallel and vector processing makes this approach competitive for many applications.
Mechanical States in Wound Capacitors: Part II — Optimization
Authors: Allen J. J. , Reuter R. C.
Published: April 2021

The winding process is encountered frequently in manufacturing, such as winding of polymer films and paper, laminated pressure vessel construction, and the manufacture of wound capacitors. The winding of capacitors will typically involve hundreds of plies of conductor and dielectric wound over a core. Due to the large number of layers, the calculation of the mechanical states within a wound capacitor is a significant computational task. Part I of this paper discussed methods for the calculation of the mechanical states within wound capacitor.

The focus of Part II of this paper is the formulation and application of optimization techniques for the design of wound capacitors. The design criteria to be achieved is a specified uniform wound tension in a capacitor. The paper will formulate an optimization statement of the wound capacitor design problem, develop a technique for reducing the numerical calculation required to repeatedly analyze the capacitor which is required by the optimization algorithm, and apply the technique to an example. The following effects will be investigated using the example.

1. The ability of low order winding tension profiles, such as constant, linear, or bilinear profiles, to meet the optimization objective.

2. The usefulness and practicality of high order winding tension profiles, which require a significant number of design variables to meet the optimization objective.

3. Differential weighting of the aluminum and mylar layer wound tensions in the objective function will be investigated as a technique for achieving the optimization/design goal.
Design of the Ball Screw Mechanism for Optimal Efficiency
Authors: Lin M.-C. , Velinsky S. A. , Ravani B.
Published: April 2021

This paper develops theories for evaluating the efficiency of the ball screw mechanism and additionally, for designing this mechanism. Initially, a quasi-static analysis, which is similar to that of the early work in this area, is employed to evaluate efficiency. Dynamic forces, which are neglected by the quasi-static analysis, will have an effect on efficiency. Thus, an exact theory based on the simultaneous solution of both the Newton-Euler equations of motion and the relevant kinematic equations is employed to determine mechanism efficiency, as well as the steady-state motion of all components within the ball screw. However, the development of design methods based on this exact theory is difficult due to the extensive computation necessary and thus, an approximate closed-form representation, that still accounts for the ball screw dynamics, is derived. The validity of this closed-form solution is proven and it is then used in developing an optimum design methodology for the ball screw mechanism based on efficiency. Additionally, the self-braking condition is examined, as are load capacity considerations.
Cyclic Symmetric Analysis of Fabricated Gear Wheels
Authors: Ramamurti V. , Subramaniam M. , Shanker B.
Published: April 2021

A computer aided method of analysis of the web portion of a spur gear is presented. The cyclic symmetric concept is used for solving the problem of the steady state stress analysis (asymmetric loading) when the gear is subjected to a concentrated edge load due to the mating tooth. The effect of cut-outs in the web is studied. The response of the web to a moving load is investigated. The ratio of the forcing frequency to the fundamental frequency of the gear wheel being small, the moving load is approximated as a static load acting at different points. The influence of radial ribs on the behaviour of the gear is also studied.
Curvature Constraints in the Design of Cam Mechanisms: Part I — Translating Flat-Face Followers
Authors: Angeles J. , Lopez-Cajun C. S. , Saha S. K.
Published: April 2021

The optimization of cam mechanisms with translating flat-face followers, upon consideration of curvature constraints, is discussed here. In fact, when minimizing the size of the cam disk, cam profiles with cusps arising from discontinuities in the curvature of the profile, can appear. On the other hand, cusps are undesirable because they give rise to inadmissibly large contact stresses and hence, should be prevented from occurring. Conditions under which these discontinuities appear, although available in the literature, are not readily applicable, for they are highly problem-dependent. However, if both the follower-displacement program and the profile are determined based on the normal spline, a design tool introduced elsewhere, then readily applicable design formulae, leading to unconstrained optimum designs, are derived. As well, design charts are derived, which produce the cusp-free, minimum-size profile for a given displacement program. The same problem for oscillating flat-face followers is addressed in an accompanying paper.
Curvature Constraints in the Design Optimization of Cam Mechanisms: Part II — Oscillating Flat-Face Followers
Authors: Angeles J. , Saha S. K. , Lopez-Cajun C. S.
Published: April 2021

This paper follows an accompanying one on the constrained minimization of cam profiles with translating flat-face followers. Here, the corresponding problem for oscillating flat-face followers is addressed. The unconstrained optimization of this type of cam mechanisms, aimed at the minimization of the area of the cam disk, has been reported elsewhere. In this paper we recognize that unconstrained cam-size minimization can lead to profiles with curvature discontinuities, i.e.. cusps, which should be eliminated, for they give rise to inadmissibly large contact stresses. The conditions under which curvature discontinuities arise are derived. These conditions lead to a simple constrained minimization procedure, whose application is illustrated with a fully solved numerical example.
Modeling, Simulation, and Modal Analysis Hydraulic Valve Lifter With Oil Compressibility Effects
Authors: Hatch T. , Pisano A. P.
Published: April 2021

A two-degree-of-freedom (2-DOF), analytical model of a hydraulic valve lifter is derived. Special features of the model include the effects of bulk oil compressibility, multi-mode behavior due to plunger check valve modeling, and provision for the inclusion of third and fourth body displacements to aid In the use of the model in extended, multi-DOF systems. It is shown that motion of the lifter plunger and body must satisfy a coupled system of third-order, non-linear differential equations of motion. It is also shown that the special cases of zero oil compressibility and/or 1-DOF motion of lifter plunger can be obtained from the general third-order equations. For the case of zero oil compressibility, using Newtonian fluid assumptions, the equations of motion are shown to reduce to a system of second-order, linear differential equations. The differential equations are numerically integrated in five scenarios designed to test various aspects of the model. A modal analysis of the 2-DOF, compressible model with an external contact spring is performed and is shown to be in excellent agreement with simulation results.
Optimization of Dynamic Forces in the Design of Mechanical Hands
Authors: Nahon M. A. , Angeles J.
Published: April 2021

Mechanical hands have become of greater interest in robotics due to the advantages they offer over conventional grippers in tasks requiring dextrous manipulation. However, mechanical hands also tend to be more complex in construction and require more sophisticated design analysis to determine the forces in the system. A mechanical hand can be described as a kinematic chain with time-varying topology which becomes redundantly actuated when an object is grasped. When this occurs, care must be exercised to avoid crushing the object or generating excessive forces within the mechanism. In the present work, this problem is formulated as a constrained quadratic optimization problem. The forces to be minimized form the objective, the dynamic equations of motion form the equality constraints and the finger-object contacts yield the inequality constraints. The quadratic-programming approach is shown to be advantageous due to its ability to minimize ‘internal forces’ A technique is proposed for smoothing the discontinuities in the force solution which occur when the toplogy changes.
A New Probabilistic Method for the Performance Evaluation of Manipulators: Part II — Application to Task Placement
Authors: Rastegar J. , Singh J. R.
Published: April 2021

A probabilistic method for optimal placement of a prescribed task space in the workspace of a robotic manipulator is presented. Velocity and force transmission (alone and in combination) are used as optimality criteria. Complex task space and manipulator workspace geometries are readily handled. The distribution of the tasks within the task space, and the velocity and force transmission requirements may assume any arbitrary form. The method is extremely simple, does not require inverse calculations, is numerical in nature, and is readily implemented on computers. In many cases, the best location of the task space within the manipulator workspace can be visually ascertained. Minimal analytical formulations are required. Several examples are presented.
The Optimum Design of a 6 DOF Fully-Parallel Micromanipulator for Enhanced Robot Accuracy
Authors: Han C.-S. , Tesar D. , Traver A. E.
Published: April 2021

The micromanipulator is a small amplitude, high resolution motion device to enhance robot accuracy by providing fine adjustments for precise error compensation and delicate force control. This paper addresses design objectives and optimization procedures for design of a unique 6 degree-of-freedom (DOF) fully-parallel micromanipulator. Using kinematic and dynamic modeling analysis, optimum geometric parameters are found which satisfy the desired motion range, effective force and velocity transmission and minimum input loading due to the bending of flexural joints. Computer simulations, optimization theory, and the finite element method are used to model, synthesize, and analyze micromanipulator components. Internal force analysis is performed to design the hardware components for critical load conditions. Using a CAD/CAM system, a full scale model of the mechanism has been created, and local stress and deflection analysis has been performed on the critical components.
Sensitivity Analysis of the Burmester Equations of Planar Motion
Authors: Mahableshwarkar S. V. , Kramer S. N.
Published: April 2021

In this paper the sensitivity of the configuration of a mechanism to small variations in the precision point locations and corresponding coupler rotations is presented. The changes in the locations of the centerpoints and circlepoints, hence the dyads constituting the mechanism, due to these variations are determined by evaluating the total differentials of these quantities. The method is applied to mechanisms designed by the Burmester Theory of Planar Motion for four precision and five precision points. This additional information on sensitivity is shown to be useful in the process of mechanism design (Mahableshwarkar, 1989). Numerical examples are included to illustrate the formulation.
Geometrically Approximated Grashof-Type Movability Conditions for Spatial RSRC Mechanisms With Transmission Angle Limitations
Authors: Rastegar J. , Tu Q.
Published: April 2021

For closed-loop spatial RSRC mechanisms, Grashof-type movability conditions (i.e., conditions for the existence of crank-rocker and drag link types of mechanisms) are derived using geometrical approximation. The movability conditions are derived in the presence and absence of transmission angle limitations. The mechanism has two branches (configurations). Without transmission angle limitations, both configurations have identical movability conditions. However, by including transmission angle limitations, the movability conditions become different for each configuration of the mechanism. The movability conditions eliminate the possibility of changeover from one configuration to the other.
Solving a Planar Four-Bar Design Problem Using Continuation
Authors: Morgan A. P. , Wampler C. W.
Published: April 2021

The problem of synthesizing a planar 4-bar with given pivots such that the coupler curve passes through live precision points is considered. It is shown that the design parameters must satisfy a system of 4 fourth-degree polynomial equations in 4 unknowns which has at most 36 nonzero real solutions.

This polynomial system is solved using a continuation method, which thereby generates the collection of all designs that meet the precision-point specification. A computer program that implements this continuation method has been tested on a number of problems. It is reliable and fast enough for the purposes of design.

The approach to kinematic design represented by this work is completely general, subject only to computer-time limitations that may arise for problems with many design elements.
Coupler-Point-Curve Synthesis Using Homotopy Methods
Authors: Tsai L.-W. , Lu J.-J.
Published: April 2021

A numerical method called “Homotopy Method” (or Continuation Method) is applied to the problem of four-bar coupler-point-curve synthesis. We have shown that: for five precision points, the “General Homotopy method” can be applied to find the link lengths of a number of four-bar linkages, and for nine precision points, a heuristic “Cheater’s Homotopy” can be applied to find some four-bar linkages. The nine-coupler-points synthesis problem is highly non-linear and highly singular. We have found that Newton-Raphson’s method and Powell’s method tend to converge to the singular solutions or do not converge at all, while the Cheater’s Homotopy always finds some non-singular solutions although sometimes the solutions may be complex.
Acoustical properties of 3D printed thermoplastics
Authors: Antoniou Anastasia , Evripidou Nikolas , Giannakou Marinos , Constantinides Georgios , Damianou Christakis
Published: April 2021

With focused ultrasound (FUS) gaining popularity as a therapeutic modality for brain diseases, the need for skull phantoms that are suitable for evaluating FUS protocols is increasing. In the current study, the acoustical properties of several three-dimensional (3D) printed thermoplastic samples were evaluated to assess their suitability to mimic human skull and bone accurately. Samples were 3D printed using eight commercially available thermoplastic materials. The acoustic properties of the printed samples, including attenuation coefficient, speed of sound, and acoustic impedance, were investigated using transmission-through and pulse-echo techniques. The ultrasonic attenuation, estimated at a frequency of 1.1 MHz, varied from approximately 7 to 32 dB/cm. The frequency dependence of attenuation was described by a power law in the frequency range of 0.2–3.5 MHz, and the exponential index of frequency was found to vary from 1.30 to 2.24. The longitudinal velocity of 2.7 MHz sound waves was in the range of 1700–3050 m/s. The results demonstrate that thermoplastics could potentially be used for the 3D construction of high-quality skull phantoms.
Smarter materials for smarter robots
Authors: Laschi Cecilia , Wood Robert J.
Published: April 2021

Advances in materials science will blur the boundaries between robots and the materials from which they are composed.
The jig is up for small soft machines
Authors: Martinez Ramses V.
Published: April 2021

A watchmaker’s approach yields small, agile, soft machines.
Unraveling DNA inspires artificial muscle
Authors: Madden John D. W.
Published: April 2021

Super-contractile artificial muscle that is inspired by DNA generates more work than skeletal muscle.
Sustained fetal hemoglobin induction in vivo is achieved by
BCL11A
interference and coexpressed truncated erythropoietin receptor
Authors: Uchida Naoya , Ferrara Francesca , Drysdale Claire M. , Yapundich Morgan , Gamer Jackson , Nassehi Tina , DiNicola Julia , Shibata Yoshitaka , Wielgosz Matthew , Kim Yoon-Sang , Bauler Matthew , Throm Robert E. , Haro-Mora Juan J. , Demirci Selami , Bonifacino Aylin C. , Krouse Allen E. , Linde N. Seth , Donahue Robert E. , Ryu Byoung , Tisdale John F.
Published: April 2021

In xenograft mice and nonhuman primates,
BCL11A
interference and coexpression of a truncated erythropoietin receptor led to sustained hemoglobin F.
Characterization of
pfmdr1
,
pfcrt
,
pfK13
,
pfubp1
, and
pfap2mu
in Travelers Returning from Africa with Plasmodium falciparum Infections Reported in China from 2014 to 2018
Authors: Feng Jun , Xu Dongmei , Kong Xiangli , Lin Kangming , Yan He , Feng Xinyu , Tu Hong , Xia Zhigui
Published: April 2021

The artemisinin-based combination therapies (ACTs) used to treat
Plasmodium falciparum
in Africa are threatened by the emergence of parasites in Asia that carry variants of the Kelch 13 (K13) locus with delayed clearance in response to ACTs. Single nucleotide polymorphisms (SNPs) in other molecular markers, such as
ap2mu
and
ubp1
, were associated with artemisinin resistance in rodent malaria and clinical failure in African malaria patients.
Complete Genome Sequences of Four Canadian Mycoplasma bovis Strains Isolated from Bison and Cattle
Authors: Menghwar Harish , Prysliak Tracy , Perez-Casal Jose
Published: April 2021

Mycoplasma bovis
is a major bacterial pathogen that causes respiratory diseases in cattle and bison. We report here the complete genome sequences of four
Mycoplasma bovis
strains isolated in three Canadian provinces. These genome sequences could provide important information on virulence factors and targets for new vaccines against
M. bovis
.
Tongue Microbiota Composition and Dental Caries Experience in Primary School Children
Authors: Zhang Daixi , Takeshita Toru , Furuta Michiko , Kageyama Shinya , Asakawa Mikari , Nambu Koki , Yamashita Yoshihisa
Published: April 2021

Dental caries is now considered to be caused by acids produced by the overall dental plaque microbiota rather than by specific pathogens. This study focused on the relationship between dental caries experience and the variations in tongue microbiota, which is adjacent but separate from the dental plaque microbiota.
Nonlinear fault damage zone scaling revealed through analog modeling
Authors: Mayolle Sylvain , Soliva Roger , Dominguez Stéphane , Wibberley Christopher , Caniven Yannick
Published: April 2021

Fault damage zones strongly influence fluid flow and seismogenic behavior of faults and are thought to scale linearly with fault displacement until reaching a threshold thickness. Using analog modeling with different frictional layer thicknesses, we investigate damage zone dynamic evolution during normal fault growth. We show that experimental damage zone growth with displacement is not linear but progressively tends toward a threshold thickness, being larger in the thicker models. This threshold thickness increases significantly at fault segment relay zones. As the thickness threshold is approached, the failure mode progressively transitions from dilational shear to isochoric shear. This process affects the whole layer thickness and develops as a consequence of fault segment linkage as inferred in nature when the fault matures. These findings suggest that fault damage zone widths are limited both by different scales of mechanical unit thickness and the evolution of failure modes, ultimately controlled in nature by lithology and deformation conditions.
How Himalayan collision stems from subduction
Authors: Soret M. , Larson K.P. , Cottle J. , Ali A.
Published: April 2021

The mechanisms and processes active during the transition from continental subduction to continental collision at the plate interface are largely unknown. Rock records of this transition are scarce, either not exposed or obliterated during subsequent events. We examine the tectono-metamorphic history of Barrovian metamorphic rocks from the western Himalayan orogenic wedge. We demonstrate that these rocks were buried to amphibolite-facies conditions from ≤47 Ma to 39 ± 1 Ma, synchronously with the formation (46 Ma) and partial exhumation (45–40 Ma) of the ultrahigh-pressure eclogites. This association indicates that convergence during continental subduction was accommodated via development of a deep orogenic wedge built through successive underplating of continental material, including the partially exhumed eclogites, likely in response to an increase in interplate coupling. This process resulted in the heating of the subduction interface (from ~7 to ~20 °C/km) through advective and/or conductive heat transfer. Rapid cooling of the wedge from 38 Ma, coeval with the formation of a foreland basin, are interpreted to result from indentation of a promontory of thick Indian crust.
Accidental adrenaline auto-injector-induced digital ischaemia: a proposed treatment algorithm
Authors: Rajiah Elizabeth , McKean Andrew R , Bain Charles
Published: April 2021

Increased numbers of adrenaline auto-injectors (AAIs) are in circulation in the UK. The rate of accidental auto-injection injuries has increased during this time. Various treatment strategies are described in the literature. We present the case of a 32-year-old, right-hand-dominant man who sustained an unintentional AAI injury to the volar aspect of his right thumb. On presentation to the emergency department, the thumb was ischaemic. There was no improvement with simple conservative measures (warm soaks). The patient was referred to our tertiary hand surgery service and a digital block using 2% lidocaine promoted reversal of ischaemia within 2 hours with no long-term sequelae. Phentolamine rescue, on standby, was not necessary in this case. In this case report, we highlight the therapeutic challenges associated with managing AAI injury and propose an evidence-based treatment algorithm to prevent risk of severe adverse outcomes such as digital necrosis.
Diabetic nephropathy and end-stage renal disease in a 28-year-old woman, or is it?
Authors: Mahmood Zainab , Barr Jayne A
Published: April 2021

A 28-year-old Hispanic woman presented to the emergency department with pneumonia and bilateral pulmonary oedema, requiring admission to the intensive care unit. Additional history included type 1 diabetes mellitus, End Stage Renal Disease on haemodialysis and Hashimoto’s disease. On further diagnostic evaluation, she was found to have systemic lupus erythematosus (SLE) with overlap syndrome. The goal of this case report was twofold: to share our holistic investigative processes and to explore how racial identity and experiences play a role in health disparities present in SLE. The diagnostic process was difficult because of language and socioeconomic barriers our patient experienced. Additionally, SLE in the Hispanic population has only recently been researched, limiting specifics about presentation and disease course. In the Hispanic population, SLE has increased morbidity and mortality when compared with the Caucasian population. Thus, our patient’s case highlights the need for holistic practices when diagnosing patients, particularly in historically and presently marginalised identities.
Dual branch solutions (multi-solutions) for nonlinear radiative Falkner–Skan flow of Maxwell nanomaterials with heat and mass transfer over a static/moving wedge
Authors: Li Yun-Xiang , Hamid Aamir , Khan M. Ijaz , Elmasry Yasser , Qayyum Sumaira , Kumar R. S. Varun , Madhukesh J. K. , Prasannakumara B. C. , Chu Yu-Ming
Published: April 2021

In this study, the numerous solutions to Falkner–Skan flow of a Maxwell fluid with nanoparticles are investigated, considering the nonlinear radiation and magnetic domain. The flow described above can be expressed in accordance with PDEs that are transformed into ODEs by choosing suitable variables of similarity. The fourth- and fifth-order Runge–Kutta–Fehlberg method can be utilized to solve these reduced ODEs by applying the shooting approach. The graphs were drawn to explain the effects of different parameters on different fluid profiles for both the lower- and upper-branch solutions. This study shows that the velocity outlines improve both solutions by increasing local Deborah numbers slightly. Besides, an increase in radiation reduces the thermal gradient for both solutions, thereby reducing the concentration gradient for both solutions contributing to raised Brownian motion and Lewis numbers.
Numerical solution of integral equations with Monte Carlo-collocation (MC-Coll) method and its application in neutron transport
Authors: Alizadeh D. , Ashrafi S. , Ghalehasadi A.
Published: April 2021

In this study, we introduce a new procedure for the numerical solution of linear and nonlinear integral equations by combining the Monte Carlo simulation and collocation method. One of the major advantages of this method is reducing calculations by converting the integral equation to a system of algebraic equations. The numerical examples of various types of integral equations indicate the efficiency and accuracy of the proposed method. The results show this method is able to solve linear and nonlinear integral equations and also nonlinear weakly singular equations, with remarkable accuracy. Finally, the method is generalized for solving integral-differential equation of the neutron transport for the stationary case.
Evaluation of Liquefied Natural Gas as a Ship Fuel for Liner Shipping Using Evolutionary Game Theory
Authors: Wu Yiwei , Wang Shuaian , Chen Ying , Chang Daofang
Published: April 2021

Strict limits on air emissions released by burning fuel of ships have recently been imposed in Emission Control Areas. Retrofitting ships to use Liquefied Natural Gas (LNG) as a ship fuel is one of the methods for liner companies to comply with global regulations. Since the LNG retrofitting investment is expensive, it is likely that liner companies need a more scientific methodology to evaluate the LNG for propulsion of ships. Liner companies are particularly interested in their profits determined by the pricing decision. Based on the evolutionary game theory, this paper develops a mathematical model for the pricing problem with the consideration of market competition, LNG investment, and price elasticity. We also consider several realistic factors, such as the demand sensitivity for LNG effort, to make the proposed methodology meet the realistic demands when more and more liner companies need a revolutionary transformation because of the stricter regulations. Numerical experiments, including a simulated-data case, are performed to validate the proposed methodology. Some managerial insights are concluded according to the computational experiments and sensitivity analysis.
Modeling and analysis of motivation-driven network behavior communication
Authors: Nian Fuzhong , Wang Xue
Published: April 2021

This paper presents a new SIRI propagation model based on SIR model. Behavioral motivation value and neighbor infection number influence value were added to the model to study the effects of these two quantities on behavior transmission. In order to make the model closer to the real situation, self-motivation value and neighbor influence value are added to the behavior motivation value. Compared with previous studies, our proposed experimental model is closer to the real world, improves the possibility of behavior prediction, and is validated by simulation. Finally, this paper takes Lanzhou Polytechnic University campus cartoon consumption data as an example to test and validate the model.
Numerical investigation of hydrodynamic characteristics of fish-like undulation using the adaptive dynamic-grid method
Authors: Guo Zeyu , Zhu Gucheng , Chen Zuogang , Feng Yukun
Published: April 2021

To investigate the hydrodynamics of undulatory swimming, a key issue in numerical analysis is to determine the correlation between undulatory locomotion and the flow characteristics. In this study, a novel dynamic-grid generation method, the adaptive control method, is implemented to deal with the moving and morphing boundaries in an unsteady flow field at all Reynolds numbers. This method, based on structured grids, can ensure the orthogonality and absolute controllability of the grids and is performed to precisely simulate the wake and the boundary layer. The NACA0010 wing is employed as a two-dimensional (2D) body model of a fish in the simulations. To maintain the calculation stability, the increase stage of the amplitude is defined as a smooth transitional stage. Analysis of hydrodynamic coefficients reveals that undulation results in a significant increase of frictional force in laminar flow [Formula: see text]. However, the undulation also results in a reduction of the frictional force when the fish swims in turbulent flow [Formula: see text]. The vorticity distribution and the [Formula: see text]-criterion are both used to accurately capture the shedding vortexes in the wake. Furthermore, these vortex pairs have a substantial impact on the turbulence and the wake, in which the turbulent kinetic energy and the turbulent viscosity ratio both decrease at [Formula: see text]. The wake of an undulatory fish presents different vortex patterns with various kinematic parameters. When the phase velocity is greater than the incoming velocity and the wave number is sufficiently large, thrust is yielded, accompanying the distinct reverse Karman Street in the wake.
Does cold inflation with dissipation mechanism in nonequilibrium thermodynamic prescription imply warm inflation?
Authors: Chakraborty Subenoy , Das Dipanjana , Dutta Sourav
Published: April 2021

The present work is an attempt to find inter relationship between the cold and warm inflationary scenarios. Here cold inflation is described by a single scalar field (inflaton) and nonequilibrium thermodynamical prescription is imposed. It is found that this quasi-de-Sitter phase of evolution is equivalent to warm inflation. The present work also addresses the question whether the dissipation is Hawking-type or not.
Siamese pyramid residual module with local binary convolution network for single object tracking
Authors: Nie Yan , Zhang Taiping , Zhao Linchang , Ma Xindi , Tang Yuanyan , Liu Xiaoyu
Published: April 2021

Visual object tracking has made rapid progress in the past few years, which has received more and more attention. It is known that the texture information plays an essential role in numerous applications, for instance, in the person reidentification, image classification and so on. In this work, we propose a kind of new framework based on Siamese networks for single object tracking, called Siamese pyramid residual module with local binary convolution network for single object tracking (SPLBCT). A local binary convolution (LBC) module is proposed for the extraction of the texture feature of the tracked objective, which can improve in-variance to lighting. A pyramid residual Module (PRM) is used to study different levels of features and achieve the fusion of multi-scale features. The combination of the LBC and PRM enhances the feature extraction of the image data. According to two object tracking benchmarks (VOT2015 and VOT2016) and online tracking benchmark (OTB100), the final experimental results show that the proposed method performs better compared with some previous trackers.
Clustering and presorting for parallel burrows wheeler-based compression
Authors: Voronin Sergey , Borovikov Eugene , Hasan Raqibul
Published: April 2021

We describe practical improvements for parallel BWT-based lossless compressors frequently utilized in modern day big data applications. We propose a clustering-based data permutation approach for improving compression ratio for data with significant alphabet variation along with a faster string sorting approach based on the application of the [Formula: see text] complexity counting sort with permutation reindexing.
Evaluating Water Savings from Budget-Based Tiered Rates in Orange County, California
Authors: Harmon Karter M. , Mukherjee Monobina , Gaur Sanjay , Atwater Drew
Published: April 2021

Interest in budget-based tiered rates (BBTRs, also referred to as water budgets) has grown across California in response to recurrent droughts, other threats to water supply, and calls for increased water-use efficiency. One major policy question surrounding BBTRs is whether or not they result in greater water-use efficiency relative to other rate structures, which results in water saving. In this paper, we provide a policy overview of BBTRs and their application in Orange County, California. We use fixed effects models to evaluate whether savings in water use occurred in two agencies which adopted BBTRs over the past decade, and the one which did not adopt BBTR but which applied a BBTR framework to provide information about water-use efficiency to consumers while retaining the existing rate structure. We also evaluate savings for three different user groups based on their average water-use characteristics, to assess whether BBTRs may produce greater savings for high-volume users relative to low- or medium-volume users. Our analysis indicates modest savings in single-family residential household water consumption attributable to BBTRs for three Orange County water agencies. Savings were realized for two agencies which converted to a budget-based rate structure at multiple levels of consumption. However, low-volume users in the agency which adopted an “informational” approach increased their water usage over the study period. This suggests that providing information on water budgets in the absence of a price signal may have limited conservation benefit, and may incentivize some low-volume users to increase their water consumption. Savings are generally higher for medium- and high-volume users than for low-volume users. We close with a discussion of our results, avenues for future research, and the limitations of this analytical framework, including the confounding effect of the 2015 historical drought and related government-mandated conservation measures. With ongoing climate change increasing the chances of more severe droughts in the future, research into the effects of alternative rate structures such as BBTRs will be valuable to water agencies and their customers.
Lexical Simplification by Unsupervised Machine Translation
Authors: Katsuta Akihiro , Yamamoto Kazuhide
Published: April 2021

In recent years, simple Japanese has been attracting attention as information transmission for foreigners. Automatic text simplification aims to reduce the complexity of vocabulary and expressions in a sentence while retaining its original meaning. This paper aims at compressing vocabulary, focusing on lexical simplification. Since the construction or expansion of a simplification corpus is very costly, we construct a simplification model by unsupervised learning that does not require a parallel corpus for simplification. We construct a simplification model that does not require a parallel corpus using Unsupervised Statistical Machine Translation. Based on a predetermined vocabulary, a pseudo-corpus for simplification is constructed from a web corpus and we learn the simplification model by the pseudo-corpus. We only need a vocabulary and a plain text corpus to train the simplification model. Moreover, we propose to clean the phrase table by WordNet, which improves the performance in BLEU and SARI metrics. By suppressing distant paraphrasing with WordNet, it became easier to select the correct paraphrase candidate.
CIKM 2020 conference report
Authors: D'Aquin Mathieu , Dietze Stefan
Published: April 2021

The 29th ACM International Conference on Information and Knowledge Management (CIKM) was held online from the 19
th
to the 23
rd
of October 2020. CIKM is an annual computer science conference, focused on research at the intersection of information retrieval, machine learning, databases as well as semantic and knowledge-based technologies. Since it was first held in the United States in 1992, 28 conferences have been hosted in 9 countries around the world.
Towards solution-oriented knowledge recommendation
Authors: Zhang Yu , Saberi Morteza , Chang Elizabeth
Published: April 2021

This research identifies three practical problems in the existing scholarly recommendation systems, which leads to three research issues related to solution-oriented scientific knowledge recommendation that have not been addressed in the literature, including the lack of solution-oriented article recommendation, the lack of solution-oriented knowledge repositories, and the lack of weighted bibliometric network for ranking academic articles. Individual research could be conducted to address each issue, however this study proposes a knowledge fusion framework to collectively integrate multiple models which are specifically designed to solve each one of the issues respectively. The framework will be able to generate valuable knowledge repositories containing the solutions proposed in the mass scholarly articles to answer academic questions, and meanwhile it can rank these solutions based on weighted bibliometric networks.
The OpenMP API for High Integrity Systems
Authors: Klemm Michael , Quiñones Eduardo , Taft Tucker , Ziegenbein Dirk , Royuela Sara
Published: April 2021

OpenMP is traditionally focused on boosting performance in HPC systems. However, other domains are showing an increasing interest in the use of OpenMP by virtue of key aspects introduced in recent versions of the specification: the tasking model, the accelerator model, and other features like the requires and the assumes directives, which allow defining certain contracts. One example is the safety-critical embedded domain, where several efforts have been initiated towards the adoption of OpenMP. However, the OpenMP specification states that "application developers are responsible for correctly using the OpenMP API to produce a conforming program", being not acceptable in high integrity systems, where aspects such as reliability and resiliency have to be ensured at different levels of criticality. In this scope, programming languages like Ada propose a different paradigm by exposing fewer features to the user, and leaving the responsibility of safely exploiting the full underlying architecture to the compiler and the runtime systems, instead. The philosophy behind this kind of model is to move the responsibility of producing correct parallel programs from users to vendors.

In this panel, actors from different domains involved in the use of parallel programming models for the development of high-integrity systems share their thoughts about this topic.
A Layered Mapping of Ada 202X to OpenMP
Authors: Taft S. Tucker
Published: April 2021

The OpenMP specification defines a set of compiler directives, library routines, and environment variables that together represent the OpenMP Application Programming Interface, and is currently defined for C, C++, and Fortran. The forthcoming version of Ada, currently dubbed Ada 202X, includes lightweight parallelism features, in particular parallel blocks and parallel loops. All versions of Ada, since its inception in 1983, have included "tasking," which corresponds to what are traditionally considered "heavyweight" parallelism features, or simply "concurrency" features. Ada "tasks" typically map to what are called "kernel threads," in that the operating system manages them and schedules them. However, one of the goals of lightweight parallelism is to reduce overhead by doing more of the management outside the kernel of the operating system, using a light-weight-thread (LWT) scheduler. The OpenMP library routines support both levels of threading, but for Ada 202X, the main interest is in making use of OpenMP for its lightweight thread scheduling capabilities.
Parallel Software to Offset the Cost of Higher Precision
Authors: Verschelde Jan
Published: April 2021

Hardware double precision is often insufficient to solve large scientific problems accurately. Computing in higher precision defined by software causes significant computational overhead. The application of parallel algorithms compensates for this overhead. Newton's method to develop power series expansions of algebraic space curves is the use case for this application.
Threespine Stickleback: A Model System For Evolutionary Genomics
Authors: Reid Kerry , Bell Michael A. , Veeramah Krishna R.
Published: April 2021

The repeated adaptation of oceanic threespine sticklebacks to fresh water has made it a premier organism to study parallel evolution. These small fish have multiple distinct ecotypes that display a wide range of diverse phenotypic traits. Ecotypes are easily crossed in the laboratory, and families are large and develop quickly enough for quantitative trait locus analyses, positioning the threespine stickleback as a versatile model organism to address a wide range of biological questions. Extensive genomic resources, including linkage maps, a high-quality reference genome, and developmental genetics tools have led to insights into the genomic basis of adaptation and the identification of genomic changes controlling traits in vertebrates. Recently, threespine sticklebacks have been used as a model system to identify the genomic basis of highly complex traits, such as behavior and host–microbiome and host–parasite interactions. We review the latest findings and new avenues of research that have led the threespine stickleback to be considered a supermodel of evolutionary genomics.
Burn-induced hypermetabolism and skeletal muscle dysfunction
Authors: Knuth Carly M. , Auger Christopher , Jeschke Marc G.
Published: April 2021

Critical illnesses, including sepsis, cancer cachexia, and burn injury, invoke a milieu of systemic metabolic and inflammatory derangements that ultimately results in increased energy expenditure leading to fat and lean mass catabolism. Burn injuries present a unique clinical challenge given the magnitude and duration of the hypermetabolic response compared with other forms of critical illness, which drastically increase the risk of morbidity and mortality. Skeletal muscle metabolism is particularly altered as a consequence of burn-induced hypermetabolism, as it primarily provides a main source of fuel in support of wound healing. Interestingly, muscle catabolism is sustained long after the wound has healed, indicating that additional mechanisms beyond wound healing are involved. In this review, we discuss the distinctive pathophysiological response to burn injury with a focus on skeletal muscle function and metabolism. We first examine the diverse consequences on skeletal muscle dysfunction between thermal, electrical, and chemical burns. We then provide a comprehensive overview of the known mechanisms underlying skeletal muscle dysfunction that may be attributed to hypermetabolism. Finally, we review the most promising current treatment options to mitigate muscle catabolism, and by extension improve morbidity and mortality, and end with future directions that have the potential to significantly improve patient care.
Ipsilateral and contralateral responses following unimanual fatigue with and without illusionary mirror visual feedback
Authors: Carr Joshua C. , Bemben Michael G. , Stock Matt S. , DeFreitas Jason M.
Published: April 2021

Illusionary mirror visual feedback is a promising clinical tool for motor rehabilitation, yet many features of its influence on motor output are unknown. We show that maximal bimanual force output is compromised to a greater extent than unimanual force output following unimanual fatigue, yet illusionary mirror visual feedback attenuates this difference. The mirror illusion also reduces the unintended EMG activity of the inactive, contralateral forearm during unimanual contraction.