bluuebunny/crossref_metadata_2025 huggingface dataset:
Vibration Isolation and Damping for Bucking Bars
Authors: Cherng John G. , Ge Tong , Peng Sheng-Lih
Published: February 2021

Bucking bars are used with pneumatic percussive rivet tools for airplanes, ships, and heavy vehicle constructions. The rivet is actually flattened by the bucking bar instead of the riveting hammer when the force is transmitted to the contact point between the rivet stem and the bucking bar. It has been proven that the operator who is holding the backing bar receives higher level of vibration than the person who is operating the rivet hammer. However, more attention has been given to the design modifications of the rivet hammer than the bucking bars which may due to the economic reasons. (The price of hammer is 50 to 100 times higher than the bucking bars’ price.) In this paper, the vibration characteristics of the bucking bars, the applications of vibration isolation and damping to the bucking bars, the optimum mass distribution calculated by a two degree-of-freedom model and the comparative results of the conventional bucking bar and ergonomically modified bucking bars are presented.
Mounting Stiffness Effects in “Free-Free” Modal Tests
Authors: Wolf Joseph A.
Published: February 2021

The fundamental issue confronting a vibration test engineer is how to obtain the best representation for the natural frequencies and corresponding mode shapes of a mechanical system. In the case of a structure such as a vehicle that has rigid body degrees of freedom, a vibration test requires some sort of artificial support system. The purpose of this work is to quantify the influence of this support system using two example structures: a one-degree-of-freedom oscillator, and a uniform beam on two types of supports. In all cases, the actual influence of the supports on the modal test results is greater than one would estimate a priori. It is hoped that these results, which have been derived from exact solutions, will provide insight for designing test supports for more complex structures.
Harmonic Analysis of Semiactive Suspensions
Authors: Ahmadian Mehdi , Reichert Brian A. , Song Xubin
Published: February 2021

This paper studies the behavior of semiactive suspensions subjected to a pure-tone input. A base-excited system, representing a single suspension, is used to compare the vibration isolation due to a conventional passive damper, an optimal passive damper, and two different types of semiactive dampers. The semiactive dampers considered are on-off (bang-bang) and continuously-variable semiactive dampers. Similar to the optimal suspension, both on-off and continuously-variable semiactive suspensions exhibited the ability to lower the resonance peak without worsening the isolation at higher frequencies. The results further show that semiactive dampers can be useful for a variety of applications including sensitive machinery that cannot tolerate any overshoot in power-up or power-down, and yet must have good isolation during normal operation.
Self-Motion Utilization for Reducing Vibration of a Structurally Flexible Redundant Robot Manipulator System
Authors: Kim Seon-Jae , Park Youn-Sik
Published: February 2021

This paper addresses the self-motion utilization of structurally flexible redundant manipulators to reduce the vibration of links when structural flexibility is present. Utilizing the self-motion capability, the motion-induced vibration can be further reduced by altering the joint trajectory during and after motion, while maintaining the end-effector tracing a given trajectory. That is because self-motion does not affect end-effector motion at all. In this proposed algorithm, a null space acceleration is evaluated in order to cancel the inertia force of flexural motion that is induced by its rigid body motion. A concept of modal space is applied to reduce the system degree of freedom. The dominant modal forces defined at a specific time, which are the same number of degree of redundancy can be effectively canceled out by employing self-motion. Through numerical simulation with three-link planar robotic manipulators, the effectiveness and applicability of the suggested method have been demonstrated.
Wavelet Based Edge Detection for Structural Dynamics
Authors: Patsias Sophoclis , Staszewski Wieslaw J. , Tomlinson Geoffrey R.
Published: February 2021

A new approach to dynamic testing/analysis based on the use of video data and edge contours is presented. Structural vibration is captured by the use of a computer video camera and wavelet analysis is then applied to each video frame. The analysis employs the discrete dyadic wavelet transform and the Mallat edge detection algorithm. The method is applied to the vibration analysis of a cantilever beam with a fault.
Motion Detection for a Precision Positioning System by Wavelet Analysis
Authors: Tai Hung-Ming , Sung Cheng-Kuo
Published: February 2021

The defects due to wear or improper assembly processes may induce undesirable vibrations that in turn cause mechanical failures. This paper employs Wavelet Transform to analyze the vibration of the pitch motion of the carriage in a precision positioning system. Two accelerometers are attached to the carriage at different locations and the accelerations are used to investigate the vibration of the pitch motion. By using Wavelet Transform, the signal measured from the proposed experimental setup are appropriately processed and used for the diagnosis of the defects. The percentage of the band energy (PBE)is found to be a helpful reference for detecting the abnormal conditions. This method successfully combines the techniques of measurement with the theory of the wavelet analysis in monitoring a precision positioning system. The difference between the results obtained both from the Short-Time Fourier analysis and wavelet analysis is also discussed.
Reliable Mode Shape Expansion Method for Error Localisation and Model Updating
Authors: Collignon Philippe , Golinval Jean-Claude
Published: February 2021

Failure detection and model updating using structural model are based on the comparison of an appropriate indicator of the discrepancy between experimental and analytical results. The reliability of the expansion of measured mode shapes is very important for the process of error localization and model updating.

Two mode shape expansion techniques are examined in this paper : the well known dynamic expansion (DE) method and a method based on the minimisation of errors on constitutive equations (MECE). A new expansion method based on some improvements of the previous techniques is proposed to obtain results that are more reliable for error localisation and for model updating.

The relative performance of the different expansion methods is demonstrated on the example of a cantilever beam.
Combining Subset Selection and Parameter Constraints in Model Updating
Authors: Friswell M. I. , Mottershead J. E. , Ahmadian H.
Published: February 2021

Model updating often produces sets of equations whose solution are ill conditioned and extra information must be used to produce a well conditioned estimation problem. One possible solution is to use regularisation, where all the possible parameters are changed, but extra constraints are introduced. This paper takes a different approach, by considering only a subset of the parameters to be in error. The critical decision is then the choice of parameters to include in the subset. The methods of subset selection are outlined and extended to the selection of groups of parameters. The incorporation of side constraints is considered and demonstrated using an experimental example.
The Influence of Experimental Errors on the Correction Parameters of Finite Element Models
Authors: Keye Stefan
Published: February 2021

A simulation study has been performed on the influence of experimental errors on the accuracy of finite element model corrections. The impact of measurement uncertainties on the sub-structure correction factors, natural frequencies, and mode shape correlation is investigated using simulated modal data. Different numerical models are used to assess the effects of modelization error magnitudes and locations.
Generalized Reference Basis Model Updating in Structural Dynamics
Authors: Kenigsbuch Rachel , Halevi Yoram
Published: February 2021

The paper considers the problem of updating an analytical model from experimental data. The approach that is taken is the reference basis, where some of the parameters are considered to be completely accurate while the others are updated by solving a constrained optimization problem. The main results of this paper are closed form solutions to these problems with general weighting matrices in the optimization criterion. These are generalizations of several model reference updating problems that were solved and reported in the literature. The importance of this generalization is the ability to incorporate prior knowledge regarding the accuracy of the model in specified areas into the method.

Another aspect of this work is the investigation of geometrical interpretation of the results which provides insight into the mechanism of the updating process. The advantages of the new updating schemes are demonstrated by means of examples.
Realization of Controllers for DC and Vector Controlled Induction Motors
Authors: Ismail Farouk , Khashab Hisham El , Mahgoub Osama , Oshiba Ahmed
Published: February 2021

Controller constants play an important role in electric drive system dynamics. The vector control permits to consider the induction motor as an equivalent separately excited DC machine, as a result, the dynamics of the two machines are compared. Experimental realization and computer simulation are constructed under PI and PID controllers.

A sensitivity study for the controllers constants and for the machines time constant is carried out and demonstrated for both machines under the same conditions. The computer simulation of the electric drive systems is constructed using the MATLAB-SIMULINK software package.
A Comprehensive Torsional Vibration Analysis Procedure: Part II
Authors: Corbo Mark A. , Malanoski Stanley B.
Published: February 2021

This is the second of two papers that provide users with a practical design procedure to ensure that their turbomachinery drive trains will not experience any torsional vibration problems in the field. In Part I, a procedure was given for determining the system’s governing interference points. Accordingly, this part focuses on the steps needed to determine the drive train’s ability to withstand these interference points.
Wave Propagation Analysis of an Axially Strained, Rotating Timoshenko Shaft: Part II
Authors: Kang Bongsu , Tan Chin An
Published: February 2021

In this paper, the wave reflection and transmission characteristics of an axially strained, rotating Timoshenko shaft under general support and boundary conditions, and with geometric discontinuities are examined. As a continuation to Part I of this paper (Kang and Tan, 1997), the wave reflection and transmission at point supports with finite translational and rotational constraints are further discussed. The reflection and transmission matrices for incident waves upon general supports and geometric discontinuities are derived. These matrices are combined, with the aid of the transfer matrix method, to provide a concise and systematic approach for the free vibration analysis of multi-span rotating shafts with general boundary conditions. Results on the wave reflection and transmission coefficients are presented for both the Timoshenko and the Euler-Bernoulli models to investigate the effects of the axial strain, shaft rotation speed, shear and rotary inertia.
Evaluation of Simplifying Assumptions in the Dynamics of Tethered Systems
Authors: Pasca Monica
Published: February 2021

Different simplifying assumptions can be formulated for the analysis of tethered systems, each of them with its own degree of fidelity and range of validity. The present paper points out the meaning of linear gravity gradient approximation for long tethers, constant tension along them and rigid deviation from the local vertical of a tethered system subjected to aerodynamic drag. A simplified model is presented and compared with numerical integration of the comprehensive nonlinear equilibrium equations. Numerical simulations refer to a probe to be flown in Martian atmosphere.
Prediction of Coupled Vibrations in Hard Disk Drive Spindle Systems
Authors: Lee Chong-Won , Jia Huan-Suo , Seo Jeong-Hwan , Kim Cheol-Soon , Chun Sang-Bok
Published: February 2021

A commercial hard disk drive spindle system is modeled as a flexible shaft with multiple flexible disks, which is supported by bearings, and its complicated coupled vibration characteristics are analyzed by using a substructure synthesis technique with the assumed-modes method. It is shown that, with the introduction of the three tuning parameters associated with the clamping radius of the disks, the stiffness of the cover and base structure and the radial stiffness of the bearings, the simulation model can well predict all the coupled modes of interest.
Effects of Head-Supported Devices on the Human and Manikin Necks
Authors: Ashrafiuon Hashem , Alem Nabih M. , McEntire B. Joseph
Published: February 2021

A comprehensive study of the effect of Head-Supported Devices (HSDs) on the neck loading during helicopter accidents is presented. The new Articulated Total Body (ATB) model which treats the neck as a deformable segment was used for crash simulation. Different categories of human and manikin subjects were considered under several crash scenarios. Simulations were theoretically designed to include a wide range of HSDs by changing their weights and C. G. (center of gravity) locations relative to the head and studying the effects of these changes. HSDs were only included as added weight and inertia to the head and their possible detachment has not been modeled in the study. Hence, two typical detachable devices were modeled and selected simulations were repeated and compared not only to provide a theoretical measure of accuracy for the original results but also to see the effect of separation of these devices from the helmet.
Testing Machines for Vibration Levels on a Test-Bed Mounting Which Is Not Similar to the Application Mounting
Authors: Lau Wai Shing , Garvey S. D. , Penny J. E. T.
Published: February 2021

Determining the level of force transmitted by a machine to its final mounting is of interest to a machine manufacturer especially if it can be done at the factory or even at the site using accelerometers. This paper examines the theoretical and practical aspects of such tests when the machine is to rigidly mounted, and when the manufacturer’s test-bed is not necessary the same as the actual final mounting. A simulated model and an experiment are described, including the difficulties associated with the conduct of similar tests. The level of force calculated is typically higher than that actually measured (for comparison).
Effect of Flexibility in Transverse Impact Problems
Authors: Yigit Ahmet S. , Christoforou Andreas P.
Published: February 2021

The nature of impact response of a flexible body is studied. The key parameters which govern the nature of impact response are identified. The effects of these parameters on the impact response are examined through numerical simulations. It is shown that the normalized impact force and the type of impact response can be predicted through the functional relationship between the normalized maximum impact force and two nondimensional parameters termed as “loss factor” and “relative stiffness”. It is expected that the results of this study will be of great value in choosing adequate impact and computational models for the dynamic analysis of multibody systems subject to transverse impacts.
Modeling a Robot With Flexible Joints and Decoupling its Equations of Motion
Authors: Meghdari Ali , Fahimi Farbod
Published: February 2021

Recent advances in the study of dynamics of multibody systems indicate the need for decoupling of the equations of motion. In this paper, our efforts are focused on this issue, and we have tried to expand the existing methods for multi-rigid body systems to include systems with some kind of flexibility. In this regard, the equations of motion for a planar two-degree-of-freedom robot with flexible joints is carried out using Lagrange’s equations and Kane’s equations with congruency transformations. The method of decoupling the equations of motion using Kane’s equations with congruency transformations is presented. Finally, the results obtained from both methods are compared.
New Component Modes for Flexible Multibody Systems
Authors: Verlinden O. , Dehombreux P. , Conti C.
Published: February 2021

In multibody systems, the deformation of a flexible body is generally modelled by a weighted summation of previously chosen deformation modes. Mode sets composed of static and vibration modes, which proved efficient in structural analysis, are commonly used in practice.

The paper presents how the classical reductions can be adapted to better fit the peculiarities of multibody systems. It is first shown how the classical mode sets can be reorganized according to the particular kinematics of a flexible body, based on a body reference frame. Secondly, it is proposed to add acceleration modes to the classical reductions to better represent the deformation during large displacements. The importance of natural boundary conditions in multibody systems is also emphasized.

The benefit of the acceleration modes and the interest of coherent natural boundary conditions are illustrated on the example of a railway engine, for two different analyses, by means of an expressly developed quality test.
A Strategy to Accelerate the Numerical Integration in the Dynamic Simulation of Multibody Systems
Authors: Cardenal Jesús , Cuadrado Javier , Bayo Eduardo
Published: February 2021

This paper presents a multi-index variable time step method for the integration of the equations of motion of constrained multibody systems in descriptor form. The basis of the method is the augmented Lagrangian formulation with projections in index-3 and index-1. The method takes advantage of the better performance of the index-3 formulation for large time steps and of the stability of the index-1 for low time steps, and automatically switches from one method to the other depending on the required accuracy and values of the time step.

The variable time stepping is accomplished through the use of an integral of motion, which in the case of conservative systems becomes the total energy. The error introduced by the numerical integrator in the integral of motion during consecutive time steps provides a good measure of the local integration error, and permits a simple and reliable strategy for varying the time step. Overall, the method is efficient and powerful; it is suitable for stiff and non-stiff systems, robust for all time step sizes, and it works for singular configurations, redundant constraints and topology changes. Also, the constraints in positions, velocities and accelerations are satisfied during the simulation process. The method is robust in the sense that becomes more accurate as the time step size decreases.
Experiments for Damage Location in a Damped Structure
Authors: Smith Suzanne Weaver , Zimmerman David C. , Bartkowicz Theodore J. , Kim Hyoung M.
Published: February 2021

In this paper, we present the results of an investigation of significant damping effects and the ability to locate damage. A three–bay, vertically cantilevered laboratory truss testbed was developed to exhibit beam–like response for the first three modes (a pair of first bending modes in orthogonal directions and a torsional mode). Truss members were removed from the testbed to simulate various damage scenarios with reduced stiffness. In addition, up to four visco–elastic damping struts were placed in the truss testbed in various configurations to affect the damping of certain modes of the structure. A comprehensive test matrix of damping and damage effects was designed and completed to construct the data base for the damping and damage identification evaluations. Two representative visco–elastic struts were also tested individually to determine their stiffness and damping characteristics. The damage detection process used the differences between pre- and post–damage vibration characteristics, along with a structural model, to successfully locate and quantify the extent of structural damage in all cases. Damping matrix models were also identified and evaluated.
Using Model Updating Technique to Train Neural Network for Fault Detection
Authors: Lopes Vicente , Pereira João Antonio , Weber Hans Ingo
Published: February 2021

Vibration monitoring and fault detection of components in manufacturing plants involve a detailed analysis of a collection of vibration data in order to establish a correlation among changes of the measured data and the corresponding fault. This work presents an alternative proposal which intent is to exploit the capability of model updating techniques associated to neural networks to reduce the amount of measured data. The updating procedure supplies a reliable model that permits to simulate any damage condition, which allows to establish a direct correlation between the deviation of the response and the corresponding fault. The learning of the net is performed using a compressed spectrum signal created for each specific type of fault. Different fault conditions for a frame structure are evaluated using simulated data and finally, the capability of the proposal is demonstrated using experimental data.
An Object-Oriented Machine Condition Monitoring Scheme for Rotating Machinery
Authors: Bettig Bernhard P. , Han Ray P. S.
Published: February 2021

The increasing reliability and accuracy of sensors as well as improvements in data acquisition and display have lead to the predictive maintenance method of scheduling machinery overhauls and replacement. Numerical models of the dynamics of a machine may be used to more accurately predict and schedule maintenance by relating variables describing deterioration mechanisms to machine measurements. For instance, vibration measurements may be used to determine bearing stiffness which is then trended. The present paper describes the concepts of a program to interactively examine and predict the health of a rotating machine. To facilitate a user-friendly implementation of the method, the paper also presents an object-oriented framework approach for introducing GUI-based graphics.
Application of Parametric Uncertainty Modeling to a Flexible Structure
Authors: Wolodkin G. , Nalbantoğlu V. , Lim K. B. , Balas G. J.
Published: February 2021

We present the results of a study in uncertainty modeling applied to the flexible structure at the University of Minnesota. In addition to additive and multiplicative uncertainty models, we examine parametric uncertainty descriptions in which the weights are obtained directly from input-output data. Two methods are examined, one based on a minimum norm model validation (MNMV) test and another in which the estimated co-variance of the parameters is used to arrive at the uncertainty weights. The resulting uncertainty models are then used to design μ-synthesis controllers, and the resulting closed-loop performance is evaluated. Additional data is taken in a closed-loop setting, and this data is used to refine the model. For the flexible structure studied, we show that the use of parametric uncertainty leads to higher performance than that attainable with purely additive or multiplicative uncertainty. Refinement of the model based on closed-loop data is also shown to result in increased performance.
A Feedforward Correction Method for Multi-Shaker Excitation System in Sine Testing
Authors: Bucher I.
Published: February 2021

In experiments aimed at structural dynamics testing, it is often required to precisely control a multi-shaker system in order to replicate the conditions a machine experiences during typical operation mode. For that purpose one seeks to create a specific pattern of responses or forces motivated by actual measured data. Another use of such tuning is for diagnostic purposes where certain forcing patterns amplify hidden features of the dynamic response. For lightly-damped structures that are normally excited by magnetic or electro-magnetic shakers, this task appears to be difficult, especially when high accuracy is desired. The excitation system, under certain conditions, creates an inherent feedback between the force and the response and often some non-linearity exist in the force path. In this paper, a systematic approach for automatic tuning the amplitude and phase of a multi-shaker in an experimental system is developed. The method is particularly useful in the presence of feedback, mild non-linearity and coupling between the force and response. The usual approach is to use a linear model and to assumed that the non-linearity is small, an approach that is valid for identification of slightly non-linear structures, but which fails when precise tuning of forces is based on this identified model. It is therefore suggested to use a general linearized model, rather than a linear one, so that any irregularities attributed to the non-linearity can be handled. Throughout the paper some simulated and experimental examples of tuning are shown. The interaction mechanism between the shakers and the structure is discussed and modeled and an appropriate strategy allowing us to overcome the demonstrated difficulties, is presented.
Transfer Path Analysis of a Vehicle Subframe: Measurements in Six Degrees of Freedom
Authors: Ivarsson Lars
Published: February 2021

A Transfer path analysis (TPA) is undertaken for a car subframe concerning six DOF of freedom and two coupling points up to 500 Hz. Integrated stingers have been developed to improve measurement results. The relative importance of the rotational components is investigated. The blocked impedance method has been used to couple the subframe to the car body using measured mobilities via two isolators out of four. The sound sensitivity is measured directly for the coupled system and compared with the total sum of the calculated transfer path components which are calculated with measured mobilities and transfer functions. Calculated and measured results show good agreement. The importance of the rotational paths depends on the characteristics of the isolator and the structures where it is mounted. It was found that the front mount position is more sensitive to rotations compared to the rear mount position. The rear mount position is also a much stiffer construction. It was found that above 220 Hz, the rotational paths are of the same importance as the translational paths when both points were connected to the body frame. It was also found that for the rear mount position, only one translational transfer path dominates. These conclusions do not differ especially for different excitation directions at the engine mount position.
Frequency Domain System Identification With Instrumental Variable Based Subspace Algorithm
Authors: McKelvey Tomas
Published: February 2021

In this paper we discuss how the time domain subspace based identification algorithms can be modified in order to be applicable when the primary measurements are given as samples of the Fourier transform of the input and output signals or alternatively samples of the transfer function. An instrumental variable (IV) based subspace algorithm is presented. We show that this method is consistent if a certain rank constraint is satisfied and the frequency domain noise is zero mean with bounded covariances. An example is presented which illuminates the theoretical discussion.
The Development of an Enhanced Mode Indicator Function Parameter Estimation Algorithm
Authors: Fladung William A. , Phillips Allyn W. , Brown David L.
Published: February 2021

The renewed interest in Multiple Reference Impact Testing has triggered the development of an Enhanced Complex Mode Indicator Function (EMIF) parameter estimation procedure. The EMIF method is a multiple degree of freedom extension of the Complex Mode Indicator Function (CMIF) method which is a simple but popular multiple reference parameter estimation procedure. The CMIF procedure uses a Enhanced Frequency Response Function (EFRF) which for many multiple reference systems looks like a single degree of freedom system over a narrow frequency band around a selected system eigenvalue. A single degree of freedom algorithm is used to obtain the system eigenvalue at the enhanced frequency. The EMIF method has been developed to handle those cases where the Single degree of freedom method is not valid.
In different shoulder pathologies, three different treatments can be performed with one needle under ultrasound guidance: technical advice
Authors: Bagcier Fatih , Yurdakul Ozan Volkan , Özduran Erkan
Published: February 2021

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Rare median nerve anatomy – possible cause for carpal tunnel syndrome?
Authors: Plaikner Michaela , Loizides Alexander , Skalla-Oberherber Elisabeth , Gruber Hannes
Published: February 2021

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Complex ultrasound evaluation of non-alcoholic fatty liver disease. “One stop shop” with new ultrasound-based techniques.
Authors: Sparchez Zeno
Published: February 2021

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Spectral contrast reduction in Australian English /l/-final rimes
Authors: Szalay Tünde , Benders Titia , Cox Felicity , Palethorpe Sallyanne , Proctor Michael
Published: February 2021

Vowel contrasts may be reduced or neutralized before coda laterals in English [Bernard (1985). The Cultivated Australian: Festschrift in Honour of Arthur Delbridge, pp. 319–332; Labov, Ash, and Boberg (2008). The Atlas of North American English, Phonetics and Sound Change (Gruyter Mouton, Berlin); Palethorpe and Cox (2003). International Seminar on Speech Production (Macquaire University, Sydney, Australia)], but the acoustic characteristics of vowel-lateral interaction in Australian English (AusE) rimes have not been systematically examined. Spectral and temporal properties of 16 pre-lateral and 16 pre-obstruent vowels produced by 29 speakers of AusE were compared. Acoustic vowel similarity in both environments was captured using random forest classification and hierarchical cluster analysis of the first three DCT coefficients of F1, F2, and F3, and duration values. Vowels preceding /l/ codas showed overall increased confusability compared to vowels preceding /d/ codas. In particular, reduced spectral contrast was found for the rime pairs /iːl-ɪl/ (feel-fill), /ʉːl-ʊl/ (fool-full), /əʉl-ɔl/ (dole-doll), and /æɔl-æl/ (howl-Hal). Potential articulatory explanations and implications for sound change are discussed.
Role of semantic context and talker variability in speech perception of cochlear-implant users and normal-hearing listeners
Authors: O'Neill Erin R. , Parke Morgan N. , Kreft Heather A. , Oxenham Andrew J.
Published: February 2021

This study assessed the impact of semantic context and talker variability on speech perception by cochlear-implant (CI) users and compared their overall performance and between-subjects variance with that of normal-hearing (NH) listeners under vocoded conditions. Thirty post-lingually deafened adult CI users were tested, along with 30 age-matched and 30 younger NH listeners, on sentences with and without semantic context, presented in quiet and noise, spoken by four different talkers. Additional measures included working memory, non-verbal intelligence, and spectral-ripple detection and discrimination. Semantic context and between-talker differences influenced speech perception to similar degrees for both CI users and NH listeners. Between-subjects variance for speech perception was greatest in the CI group but remained substantial in both NH groups, despite the uniformly degraded stimuli in these two groups. Spectral-ripple detection and discrimination thresholds in CI users were significantly correlated with speech perception, but a single set of vocoder parameters for NH listeners was not able to capture average CI performance in both speech and spectral-ripple tasks. The lack of difference in the use of semantic context between CI users and NH listeners suggests no overall differences in listening strategy between the groups, when the stimuli are similarly degraded.
Supplemental Material: Transition from a passive to active continental margin setting for the NE Asian continental margin during the Mesozoic: Insights from the sedimentary formations and paleogeography of the eastern Jiamusi Massif, NE China
Authors: Wang Yini , Xu Wenliang , al. et
Published: February 2021

Zircon U-Pb data and zircon Hf isotopic data.
Can TEN4 distinguish bruises from abuse, inherited bleeding disorders or accidents?
Authors: Kemp Alison Mary , Maguire Sabine Ann , Nuttall Dianne E , Collins Peter , Dunstan Frank D , Farewell Daniel
Published: February 2021

Objective

Does TEN4 categorisation of bruises to the torso, ear or neck or any bruise in <4-month-old children differentiate between abuse, accidents or inherited bleeding disorders (IBDs)?

Design

Prospective comparative longitudinal study.

Setting

Community.

Patients

Children <6 years old.

Interventions

The number and location of bruises compared for 2568 data collections from 328 children in the community, 1301 from 106 children with IBD and 342 abuse cases.

Main outcome measures

Likelihood ratios (LRs) for the number of bruises within the TEN and non-TEN locations for pre-mobile and mobile children: abuse vs accidental injury, IBD vs accident, abuse vs IBD.

Results

Any bruise in a pre-mobile child was more likely to be from abuse/IBD than accident. The more bruises a pre-mobile child had, the higher the LR for abuse/IBD vs accident. A single bruise in a TEN location in mobile children was not supportive of abuse/IBD. For mobile children with more than one bruise, including at least one in TEN locations, the LR favouring abuse/IBD increased. Applying TEN4 to collections from abused and accidental group <48 months of age with at least one bruise gave estimated sensitivity of 69% and specificity for abuse of 74%.

Conclusions

These data support further child protection investigations of a positive TEN4 screen in any pre-mobile children with a bruise and in mobile children with more than one bruise. TEN4 did not discriminate between IBD and abuse, thus IBD needs to be excluded in these children. Estimated sensitivity and specificity of TEN4 was appreciably lower than previously reported.
Tuberculous mycotic aneurysm of aortic arch: a case report emphasising on multidisciplinary management approach
Authors: Velu Dhivya , Ibrahim Farrah , Hassoun Ali
Published: February 2021

Although tuberculosis (TB) is a well-known infection worldwide, the disease involvement in blood vessels, mainly aorta, is quite rare. The objective of this case report is to address the importance of a multidisciplinary approach aiming at successful treatment of tuberculosis, especially when presenting with mycotic aneurysm. We report a case of a 45-year-old woman with the history of sputum positive pulmonary TB, presenting with seizures and eventually found to have developed disseminated infection involving multiple organs, including the aorta. The patient was started on WHO-recommended anti-tubercular treatment but ended up requiring surgical intervention for the aneurysm. Although the main modality of treatment is the use of proper and adequate medical therapy, vascular dissemination in the form of mycotic aneurysm is difficult to be dealt singlehandedly due to their irreversible and multifactorial nature, with infection being the leading cause and their tendency to progress despite the primary infection being treated.
Pregnant patient with extranodal CNS Rosai-Dorfman disease with new-onset seizures: the conundrum of differentiating disease progression from eclampsia
Authors: Swor Katie , Zutshi Deepti , Dubey Elizabeth , Gonik Bernard
Published: February 2021

A 31-year-old woman at 30 weeks gestation presented to the emergency department following multiple seizures. Her history was significant for extranodal Rosai-Dorfman Disease (RDD) with central nervous system (CNS) lesions. RDD, a rare form of non-Langerhans cell histiocytosis, commonly presents with non-tender cervical lymphadenopathy. CNS involvement accounts for a small number of cases in those with extranodal disease. Patients with CNS RDD can have a variety of neurological symptoms, including seizures. Eclampsia, a relatively rare obstetric hypertensive disorder, is always within the differential diagnosis for patients presenting with late gestation seizures. We present the challenging evaluation and treatment of a patient whose clinical picture did not clearly differentiate eclampsia from new onset seizures related to progression of her RDD. This conundrum perhaps resulted in unnecessary preterm operative delivery of a critically ill patient. Only follow-up of the patient helped clarify the likely antepartum diagnosis.
Evaluation of management factors affecting the relative success of a brook trout eradication program using YY male fish and electrofishing suppression
Authors: Day Casey C. , Landguth Erin L. , Simmons Ryan K. , Baker William P. , Whiteley Andrew R. , Lukacs Paul M. , Davenport Kaeli A. , Bearlin Andrew R.
Published: February 2021

Removal of non-native fish populations can be crucial to the conservation of native species, but often presents a complex challenge for managers. The goal of Trojan Y chromosome (TYC) programs is to skew the non-native sex ratio until only males remain, leading to eradication. We present results from a simulation model used to explore effects of alternative management approaches on an in-progress mechanical removal and TYC program to eradicate non-native brook trout (Salvelinus fontinalis). Simulation results indicated that stocking fingerling YY males (∼137 mm) was more effective than stocking catchable-sized YY males (∼230 mm), although questions about intercohort competition warrant further investigation. Increasing the proportion of mature fingerling YY males reduced treatment time by increasing the number of YY male spawners and increasing density-dependent mortality on young, mature wild brook trout. Maximizing the spatial distribution of YY male releases may be crucial to program success but is also dependent upon immediate dispersal movements. Principles derived from our results can be broadly applied to the management of other aquatic invaded systems using TYC programs to eradicate non-native species.
Genome-wide association study to identify soybean stem pushing resistance and lodging resistance loci
Authors: Kato Shin , Samanfar Bahram , Morrison Malcolm J. , Bekele Wubishet A. , Torkamaneh Davoud , Rajcan Istvan , O’Donoughue Louise , Belzile François , Cober Elroy R.
Published: February 2021

Lodging resistance is an important objective for soybean [Glycine max (L.) Merr.] breeding, but selection for this trait has been difficult since the resistance is controlled by multiple genes, and these genes interact with the environment. A total of 130 of 139 lines constituting a soybean genome-wide association study panel were phenotyped for stem pushing resistance, which is defined as the push-back strength when the plant stem is inclined, by measuring the force required to push a stem to a 45° angle using a force gauge in a greenhouse, and also for lodging, plant height, seed yield, and maturity at three locations in total in eastern Canada in 2013 or 2017. Two quantitative trait loci (QTLs) for pushing resistance were identified on chromosome 5 and 11, and each QTL accounted for 16.0% of phenotypic variation. In our panel, the alleles for higher pushing resistance were always of lower frequency than the alternate allele. Examining the panel at these QTLs identified that higher pushing resistance was associated with lower lodging on chromosomes 5 and 11, and that the difference for lodging between alleles was significant on chromosome 5. There was no difference in plant height or yield at the QTL on chromosomes 5 or 11, while higher pushing resistance was associated with later maturity at both QTLs. The pushing resistance QTL on chromosome 11 will be useful for decreasing lodging in Canadian short-season soybean.
Relative dynamical degree of monomial maps
Authors: Lee Chunghyun
Published: February 2021

We compute all relative dynamical degrees of equivariant dominant rational maps on toric varieties. We use the intersection theory on toric varieties using Minkowski weights. As a result, we see that the relative dynamical degrees can be reduced to the dynamical degrees on toric varieties. Hence these are all algebraic integers.
A note on the ADHM description of Quot schemes of points on affine spaces
Authors: Henni Abdelmoubine A. , Guimarães Douglas M.
Published: February 2021

We give an Atiyah–Drinfel’d–Hitchin–Manin (ADHM) description of the Quot scheme of points [Formula: see text] of length [Formula: see text] and rank [Formula: see text] on affine spaces [Formula: see text] which naturally extends both Baranovsky’s representation of the punctual Quot scheme on a smooth surface and the Hilbert scheme of points on affine spaces [Formula: see text] described by the first author and M. Jardim. Using results on the variety of commuting matrices, and combining them with our construction, we prove new properties concerning irreducibility and reducedness of [Formula: see text] and its punctual version [Formula: see text] where [Formula: see text] is a fixed point on a smooth affine variety [Formula: see text]. In this last case, we also study a connectedness result, for some special cases of higher [Formula: see text] and [Formula: see text].
Charged perfect fluid dark matter model: Known mass density function approach
Authors: Ghosh Mithun
Published: February 2021

The concept of dark matter has been imported to explain the observed velocity profile of the spiral galaxies, the flat rotational velocity. Taking the flatness of rotation curves as an input and assuming that the galactic halo is filled with charged perfect fluid having known mass density function, we obtain a space time metric in the galactic halo region. The acquired solution indicates to a (nearly) flat universe, consistent with the present day cosmological observations. Various other aspects of the solution such as attractive gravity in the halo region, stability of the circular orbit, etc., are also analyzed.
Capability plots of dynamic positioning for the semi-submersible platform in internal solitary waves
Authors: Zhang Jing-Jing , Liu Yi , Chen Ke , You Yun-Xiang
Published: February 2021

Based on the experimentally detected forces induced by internal solitary waves (ISWs), an analysis on capability of dynamic positioning (DP) for the semi-submersible platform model under the influence of different ISW-amplitudes with three kinds of ocean stratified conditions is carried out. The environmental forces acting on the semi-submersible platform arise due to the following two main components: the measurements of ISW-forces and calculations of the wind, currents and waves. Combined with quadratic programming (QP) methods, extreme safe amplitudes under different upper layer depths and the DP strategy are proposed. It is obvious from the experimental results that both the maximum and minimum horizontal ISW-forces increase linearly with the wave amplitudes under different layer thickness ratios, and the upper layer depth has a significant effect on the ISW-forces. Reference to the obtained results from the DP capability simulation reveals that the maximum thrust, with overloading, appears at heading angles of 90[Formula: see text] and 270[Formula: see text] under different upper layer depths, whilst the minimum thrust is under angles of 0[Formula: see text] and 180[Formula: see text].
Online Detecting of Inter-Turn Short-Circuit in Generator Rotor Winding Relying on ν-SVR Machine
Authors: Pan Feng , Guo Xiansheng , Pan Shengwang
Published: February 2021

To probe an accurate diagnosing approach for synchronous generator (SG) with rotor winding inter-turn short-circuit, a novel online monitoring and detecting method relying on the [Formula: see text]-support vector regression ([Formula: see text]-SVR) machine was proposed, and its effectiveness was further verified by the micro-synchronous generator dynamic simulation. Terminal voltage, active and reactive power of SG were selected as input variables for a novel prediction model based on the [Formula: see text]-SVR, and field current was selected as an output variable of the prediction model. The structures and parameters of the field current prediction model were optimized with the particle swarm optimization (PSO) algorithm and training samples, then the prediction model was established and the field current prediction got under way. By comparing the predicted field current with the corresponding online measured field current, inter-turn short-circuit of rotor winding in SG could be detected sensitively once its absolute value of the prediction relative error exceeded a specific threshold. The micro-synchronous generator dynamic simulation indicated that the proposed online detecting approach based on the [Formula: see text]-SVR machine overcame the shortage of the back-propagation (BP) diagnosis method for misdiagnosis, and its accuracy, sensitivity and threshold setting range of the diagnosis method was the most prominent among these diagnosis methods such as the BP diagnosis method, the Bayesian regularization back-propagation (BRBP) diagnosis method and the [Formula: see text]-support vector regression ([Formula: see text]-SVR) diagnosis method.
Improved Camera Calibration Method and Accuracy Analysis for Binocular Vision
Authors: Zhang Ben , Zhu Denglin
Published: February 2021

The quality of the stereo camera calibration method governs the accuracy of the binocular vision and thus determines the precision of the 3D reconstruction. Spurred by that, in this paper, we propose an improved calibration method that increases the calibration accuracy by optimizing the captured corners. Our method is multi-staged, where first, we employ the Harris corner detector to identify the uncertainties of all image corners. Then, for each detected corner, we apply a linear optimization, and finally, we calibrate the intrinsic and extrinsic parameters of the binocular vision setup by employing a nonlinear optimization scheme. We confirm the validity of our technique by analyzing the factors influencing the camera calibration accuracy and confirm the experimental conditions. Ultimately, we evaluate the proposed method and demonstrate that the mean error of our binocular vision architecture is more appealing compared to current literature.
Intelligent Equalization Based on RBF LSSVM and Adaptive Channel Decoding in Faster-than-Nyquist Receiver
Authors: Li Lu , Fan Xinyu , Gong Haimei , Wang Yuanqi , Wang Lei
Published: February 2021

On one hand, aiming at the prominent problem of improving the reliability of Faster-than-Nyquist (FTN) wireless transmission, abandoning the channel estimation, we propose the Radial Basis Function Least Squares Support Vector Machine (RBF LSSVM) algorithm based on Intelligent Signal Processing for FTN equalization and form FTN time domain transverse filter equalizer. The model of FTN wireless communication system based on equalization of LSSVM algorithm is established by adding 50-bit training sample sequence module. On the other hand, in the FTN transmission BPSK modulation system receiving terminal, we propose joint research equalization of LSSVM algorithm and adaptive channel decoding scheme of Chase algorithm, to improve the reliable transmission performance of FTN wireless communication. The threshold value is 20, and the adaptive 2-D Turbo Product Codes (TPC) encoding and decoding is simulated by four iterations. The BER performance of FTN wireless communication combined with LSSVM algorithm and TPC adaptive decoding is simulated.