bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolutionary Design of Planar Kinematic Chains
Authors: Nielsen David R. , Kazerounian Kazem 
Published: February 2021

Abstract
A procedure is developed to optimize planar mechanism type. A Genetic Algorithm is used to cycle populations of kinematic chain link adjacency matrices, through selection, crossover, and mutation. During this optimization, fit kinematic chains survive while unfit kinematic chains do not. Upon convergence, synthesized kinematic chains of high fitness remain. This technique was lead to be called the Genetic Algorithm for Type Synthesis (GATS). GATS introduces four new ideas for the type synthesis of mechanisms. First, it does not permute all possible kinematic chains. It searches for the best kinematic chains depending on a designer’s specifications. Second, larger size mechanisms can be generated because of the genetic algorithm’s evolutionary naturalness. Third, a novel approach was applied to genetic algorithms to allow the encodings to mutate in size. This allowed for addition or elimination of links in kinematic chains during evolution. Forth, a new property was deduced from mechanism topography that describes the mechanism design flexibility.
A Simple Finite Element Based Model for a Constrained-Layer of Viscoelastic Material: Part II — Application to Flexible Mechanism Systems
Authors: Sisemore Carl , Smaili Ahmad 
Published: February 2021

Abstract
This article investigates the effectiveness of constrained layer viscoelastic damping treatments in reducing the steady-state elastodynamic vibrations in flexible linkage mechanisms. The simple model that was proposed and verified in Part-I of this dual article is used to model the constrained layer of viscoelastic material applied to the coupler link of a flexible 4R mechanism. Full layer and patched layers of damping treatment are applied to the mechanism with three drive train conditions. The results indicate that with proper modeling of the mechanism as a system constrained layer passive damping can be very effective in reducing vibration magnitudes in flexible mechanisms.
Trajectory Synthesis for Selective Elimination of High Frequency Actuating Torque Harmonics
Authors: Ge Q. J. , Rastegar J. , Mattice M. 
Published: February 2021

Abstract
This paper deals with the problem of synthesizing joint trajectories of computer controlled machinery with tailored harmonic content for the actuating torques required to track the trajectories. For point-to-point motions with zero initial and final velocities and accelerations, a method is presented for shaping the harmonic content of the joint trajectories for the purpose of eliminating a specified high-frequency harmonic from the actuating torques. With such trajectories, the machine can perform the synthesized tasks with less residual vibration and increased settling time.
Singularity Analysis of a Class of the 6-6 Stewart Platforms
Authors: Wang Guozhen 
Published: February 2021

Abstract
In this paper, a method is presented for singularity analysis for a special form of the Stewart Platform in which the top and base platforms are similar in shape and the corresponding joints are connected by six prismatic joints. Analytical singularity conditions of this class of Stewart platform are derived by using the method. Examples are given to illustrate the theoretical results. It is shown that at the singular case, two or more pairs of branches of direct kinematic problems meet at the singular point.
Kinematics, Dynamics, and Control of Tendon-Driven Mechanisms Using Signal Flow Graphs
Authors: Chew Meng-Sang , Wongratanaphisan Theeraphong 
Published: February 2021

Abstract
This paper presents the analysis of the kinematics, dynamics and controls of tendon-driven mechanism under the framework of signal flow graphs. For decades, the signal flow graphs have been applied in many areas, particularly in controls, for determining the closed-loop transfer function of a control system. The tendon-driven mechanism considered here consists of several subsystems including actuator-controller dynamics, mechanism kinematics and mechanism dynamics. Each subsystem will be derived and represented by signal flow graphs. The representation of the whole system can be carried out by connecting the graphs of subsystems at the corresponding nodes. Transfer functions can then be obtained by using Mason’s rules. A 3-DOF robot finger utilizing tendon-driven mechanism is used as an illustrative example.
Architecture Optmization of a 3-DOF Parallel Mechanism
Authors: Carretero J. A. , Podhorodeski R. P. , Nahon M. 
Published: February 2021

Abstract
This paper presents a study of the architecture optimization of a three-degree-of-freedom parallel mechanism intended for use as a telescope mirror focussing device. The construction of the mechanism is first described. Since the mechanism has only three degrees of freedom, constraint equations describing the inter-relationship between the six Cartesian coordinates are given. These constraints allow us to define the parasitic motions and, if incorporated into the kinematics model, a constrained Jacobian matrix can be obtained. This Jacobian matrix is then used to define a dexterity measure. The parasitic motions and dexterity are then used as objective functions for the optimizations routines and from which the optimal architectural design parameters are obtained.
A Comparative Study on Some Modular Approaches for Analysis and Synthesis of Planar Linkages: Part II — Modular Dynamic Analysis, Modular Structural Synthesis and Modular Kinematic Synthesis
Authors: Yang Ting-Li , Yao Fang-Hua , Zhang Ming 
Published: February 2021

Abstract
This paper presents a systematical comparative study of various modular methods based on the different module types: basic kinematic chains (BKCs), single opened chains (SOCs), loops (or a tree and co-tree), links-joints, etc. for analysis and synthesis of structure, kinematics and dynamics of planar linkages. The basic idea is that any linkage can be divided into (or built up by) some modular components in sequence, and based on the component constraints and network entirty constraints of the linkage, the unified modular approaches have been used for analysis and synthesis. In systematical comparative study, the main issues of a modular method have been discussed, such as: the topological characteristics revealed via different module types; the dimension of a set of kinematic equations; the automated generation and solution of kinematic equations; the dimension and automated generation of dynamical equations, and computation complexity for generating and solving dynamical equation; the automated generation of structural analysis and type synthesis; the generation of kinematic synthesis equations etc.. This paper gives a summary of the use of modular techniques for analyzing and synthesizing planar linkages in the recently thirty years. This comparative study includes two parts: Part I-modular structural analysis and modular kinematic analysis; Part II-modular dynamic analysis, modular structural synthesis and modular kinematic synthesis. This paper is the second part.
Computerized Design, Generation and Simulation of Meshing of a Spiroid Worm-Gear Drive With Double-Crowned Worm
Authors: De Donno Mauro , Litvin Faydor L. 
Published: February 2021

Abstract
The authors propose methods of computerized design and analysis of a spiroid worm-gear drive with ground worm based on the following considerations:
(1) The theoretical thread surface of the hob is generated by a cone surface.
(2) The worm surface is crowned in profile and longitudinal directions in comparison with the hob thread surface.
(3) The double crowning of the worm enables to localize the bearing contact and obtain a predesigned parabolic function of transmission errors of an assigned level.
Computerized design of the worm-gear drive enables to discover and avoid singularities of the generated worm face-gear surface and pointing of teeth.
The meshing and contact of the double-crowned worm and the worm face-gear is simulated to determine the influence of misalignment on the shift of bearing contact and transmission errors. Computer program for numerical solution is developed and applied.
A numerical example that illustrates the developed theory is provided.
Using Dynamic Analysis for Compact Gear Design
Authors: Lin Ping-Hsun , Lin Hsiang Hsi , Oswald Fred B. , Townsend Dennis P. 
Published: February 2021

Abstract
This paper presents procedures for designing compact spur gear sets with the objective of minimizing the gear size. The allowable tooth stress and dynamic response are incorporated in the process to obtain a feasible design region. Various dynamic rating factors were investigated and evaluated. The constraints of contact stress limits and involute interference combined with the tooth bending strength provide the main criteria for this investigation. A three-dimensional design space involving the gear size, diametral pitch, and operating speed was developed to illustrate the optimal design of spur gear pairs.
The study performed here indicates that as gears operate over a range of speeds, variations in the dynamic response change the required gear size in a trend that parallels the dynamic factor. The dynamic factors are strongly affected by the system natural frequencies. The peak values of the dynamic factor within the operating speed range significantly influence the optimal gear designs. The refined dynamic factor introduced in this study yields more compact designs than AGMA dynamic factors.
Vibrations of Aircraft Gear Systems and Their Isolation
Authors: Buyukataman K. , Kazerounian K. 
Published: February 2021

Abstract
One of the most destructive factors in gear components with thin cylindrical rims, is the excessive stresses caused by the radial resonance modes. Dry friction dampers are an effective means of reducing structural vibratory response of gear components. This paper is the continuation of a previous report on vibration damping of aircraft gears [Buyukataman, AIAA-91-2550]. Similar notation and examples are used in this work. However, unlike the previous work which had stressed the damping mechanics and the design of the dampers, this report concentrates on computer implementation and design optimization of dampers.
SARS-CoV-2 transmission during rugby league matches: do players become infected after participating with SARS-CoV-2 positive players?
Authors: Jones Ben , Phillips Gemma , Kemp Simon , Payne Brendan , Hart Brian , Cross Matthew , Stokes Keith A 
Published: February 2021

ObjectivesTo examine the interactions between SARS-CoV-2 positive players and other players during rugby league matches and determine within-match SARS-CoV-2 transmission risk.MethodsFour Super League matches in which SARS-CoV-2 positive players were subsequently found to have participated were analysed. Players were identified as increased-risk contacts, and player interactions and proximities were analysed by video footage and global positioning system (GPS) data. The primary outcome was new positive cases of SARS-CoV-2 within 14 days of the match in increased-risk contacts and other players participating in the matches.ResultsOut of 136 total players, there were 8 SARS-CoV-2 positive players, 28 players identified as increased-risk contacts and 100 other players in the matches. Increased-risk contacts and other players were involved in 11.4±9.0 (maximum 32) and 4.0±5.2 (maximum 23) tackles, respectively. From GPS data, increased-risk contacts and other players were within 2 m of SARS-CoV-2 positive players on 10.4±18.0 (maximum 88) and 12.5±20.7 (maximum 121) occasions, totalling 65.7±137.7 (maximum 689) and 89.5±169.4 (maximum 1003) s, respectively. Within 14 days of the match, one increased-risk contact and five players returned positive SARS-CoV-2 reverse transcriptase PCR (RT-PCR) tests, and 27 increased-risk contacts and 95 other participants returned negative SARS-CoV-2 RT-PCR tests. Positive cases were most likely traced to social interactions, car sharing and wider community transmission and not linked to in-match transmission.ConclusionDespite tackle involvements and close proximity interactions with SARS-CoV-2 positive players, in-match SARS-CoV-2 transmission was not confirmed. While larger datasets are needed, these findings suggest rugby presents a lower risk of viral transmission than previously predicted.
Evaluating the association of preoperative parecoxib with acute pain trajectories after video-assisted thoracoscopic surgery: a single-centre cohort study in Taiwan
Authors: Ling Yu-Hsiang , Tai Ying-Hsuan , Wu Hsiang-Ling , Fu Wei-Lun , Tsou Mei-Yung , Chang Kuang-Yi 
Published: February 2021

ObjectiveThe efficacy of parecoxib as pre-emptive analgesia still remains controversial. This study aimed to investigate how pre-emptive analgesia with parecoxib affected postoperative pain trajectories over time in patients undergoing thoracic surgery.DesignRetrospective cohort study.SettingA single medical centre in Taiwan.ParticipantsWe collected 515 patients undergoing video-assisted thoracoscopic surgery at a tertiary medical centre between September 2016 and August 2017.InterventionsPre-emptive parecoxib before surgery.Primary and secondary outcome measuresDaily numeric rating pain scores in the first postoperative week.ResultsA total of 196 (38.1%) of the recruited patients received parecoxib preoperatively. The latent curve analysis revealed that woman, higher body weight and postoperative use of parecoxib were associated with increased baseline level of pain scores over time (p=0.035, 0.005 and 0.048, respectively) but epidural analgesia and preoperative use of parecoxib were inclined to decrease it (both p<0.001). Regarding the decreasing trends of changes in daily pain scores, older age and epidural analgesia tended to steepen the slope (p=0.014 and <0.001, respectively). Preoperative use of parecoxib were also related to decreased frequency of rescue morphine medication (HR=0.4; 95% CI 0.25 to 0.65).ConclusionsPre-emptive analgesia with parecoxib was associated with decreased baseline pain scores but had no connection with pain decreasing trends over time. Latent curve analysis provided insights into the dynamic relationships among the analgesic modalities, patient characteristics and postoperative pain trajectories.
Seroprevalence of antibodies to SARS-CoV-2 in healthcare workers: a cross-sectional study
Authors: Ebinger Joseph E , Botwin Gregory J , Albert Christine M , Alotaibi Mona , Arditi Moshe , Berg Anders H , Binek Aleksandra , Botting Patrick , Fert-Bober Justyna , Figueiredo Jane C , Grein Jonathan D , Hasan Wohaib , Henglin Mir , Hussain Shehnaz K , Jain Mohit , Joung Sandy , Karin Michael , Kim Elizabeth H , Li Dalin , Liu Yunxian , Luong Eric , McGovern Dermot P B , Merchant Akil , Merin Noah , Miles Peggy B , Minissian Margo , Nguyen Trevor Trung , Raedschelders Koen , Rashid Mohamad A , Riera Celine E , Riggs Richard V , Sharma Sonia , Sternbach Sarah , Sun Nancy , Tourtellotte Warren G , Van Eyk Jennifer E , Sobhani Kimia , Braun Jonathan G , Cheng Susan 
Published: February 2021

ObjectiveWe sought to determine the extent of SARS-CoV-2 seroprevalence and the factors associated with seroprevalence across a diverse cohort of healthcare workers.DesignObservational cohort study of healthcare workers, including SARS-CoV-2 serology testing and participant questionnaires.SettingsA multisite healthcare delivery system located in Los Angeles County.ParticipantsA diverse and unselected population of adults (n=6062) employed in a multisite healthcare delivery system located in Los Angeles County, including individuals with direct patient contact and others with non-patient-oriented work functions.Main outcomesUsing Bayesian and multivariate analyses, we estimated seroprevalence and factors associated with seropositivity and antibody levels, including pre-existing demographic and clinical characteristics; potential COVID-19 illness-related exposures; and symptoms consistent with COVID-19 infection.ResultsWe observed a seroprevalence rate of 4.1%, with anosmia as the most prominently associated self-reported symptom (OR 11.04, p<0.001) in addition to fever (OR 2.02, p=0.002) and myalgias (OR 1.65, p=0.035). After adjusting for potential confounders, seroprevalence was also associated with Hispanic ethnicity (OR 1.98, p=0.001) and African-American race (OR 2.02, p=0.027) as well as contact with a COVID-19-diagnosed individual in the household (OR 5.73, p<0.001) or clinical work setting (OR 1.76, p=0.002). Importantly, African-American race and Hispanic ethnicity were associated with antibody positivity even after adjusting for personal COVID-19 diagnosis status, suggesting the contribution of unmeasured structural or societal factors.Conclusion and relevanceThe demographic factors associated with SARS-CoV-2 seroprevalence among our healthcare workers underscore the importance of exposure sources beyond the workplace. The size and diversity of our study population, combined with robust survey and modelling techniques, provide a vibrant picture of the demographic factors, exposures and symptoms that can identify individuals with susceptibility as well as potential to mount an immune response to COVID-19.
Can routine blood tests be modelled to detect advanced liver disease in the community: model derivation and validation using UK primary and secondary care data
Authors: Hydes Theresa , Moore Michael , Stuart Beth , Kim Miranda , Su Fangzhong , Newell Colin , Cable David , Hales Alan , Sheron Nick 
Published: February 2021

ObjectivesMost patients are unaware they have liver cirrhosis until they present with a decompensating event. We therefore aimed to develop and validate an algorithm to predict advanced liver disease (AdvLD) using data widely available in primary care.Design, setting and participantsLogistic regression was performed on routinely collected blood result data from the University Hospital Southampton (UHS) information systems for 16 967 individuals who underwent an upper gastrointestinal endoscopy (2005–2016). Data were used to create a model aimed at detecting AdvLD: ‘CIRRhosis Using Standard tests’ (CIRRUS). Prediction of a first serious liver event (SLE) was then validated in two cohorts of 394 253 (UHS: primary and secondary care) and 183 045 individuals (Care and Health Information Exchange (CHIE): primary care).Primary outcome measuresModel creation dataset: cirrhosis or portal hypertension. Validation datasets: SLE (gastro-oesophageal varices, liver-related ascites or cirrhosis).ResultsIn the model creation dataset, 931 SLEs were recorded (5.5%). CIRRUS detected cirrhosis or portal hypertension with an area under the curve (AUC) of 0.90 (95% CI 0.88 to 0.92). Overall, 3044 (0.8%) and 1170 (0.6%) SLEs were recorded in the UHS and CHIE validation cohorts, respectively. In the UHS cohort, CIRRUS predicted a first SLE within 5 years with an AUC of 0.90 (0.89 to 0.91) continuous, 0.88 (0.87 to 0.89) categorised (crimson, red, amber, green grades); and AUC 0.84 (0.82 to 0.86) and 0.83 (0.81 to 0.85) for the CHIE cohort. In patients with a specified liver risk factor (alcohol, diabetes, viral hepatitis), a crimson/red cut-off predicted a first SLE with a sensitivity of 72%/59%, specificity 87%/93%, positive predictive value 26%/18% and negative predictive value 98%/99% for the UHS/CHIE validation cohorts, respectively.ConclusionIdentification of individuals at risk of AdvLD within primary care using routinely available data may provide an opportunity for earlier intervention and prevention of liver-related morbidity and mortality.
Effect of consumption of animal milk compared to infant formula for non-breastfed/mixed-fed infants 6–11 months of age: a systematic review (protocol)
Authors: Imdad Aamer , Ehrlich Julie Melissa , Catania Joseph , Tanner-Smith Emily , Smith Abigail , Tsistinas Olivia , Bhutta Zulfiqar Ahmed 
Published: February 2021

IntroductionPrevalence rates of breastfeeding remain low even though the World Health Organization (WHO) and the American Academy of Pediatrics recommend exclusive breast feeding for the first 6 months of life in combination with appropriate complementary feeding beyond six 6 months of age. There have been several studies that address the implication of drinking animal milk and/or infant formula on children’s health and development when breast feeding is not offered during the first year of life. Vast improvements have been made in infant formula design, which may increase its benefits compared with animal’s milk. The objective of this review is therefore to synthesise the most recent evidence on the effects of the consumption of animal milk compared with infant formula in non-breastfed or mixed breastfed infants aged 6–11 months.Methods and analysisWe will conduct a systematic review and meta-analysis of studies that assessed the effect of animal milk compared with formula or mixed-fed (breastmilk and formula) on infants aged 6–11 months. The primary outcomes of interest include anaemia, gastrointestinal blood loss, weight for age, height for age and weight for height. We will include randomised and non-randomised studies with a control group. We will use the Cochrane risk of bias tools to assess the risk of bias. We will use meta-analysis to pool findings if the identified studies are conceptually homogenous and data are available from more than one study. We will assess the overall quality of evidence using the Grading of Recommendations Assessment, Development, and Evaluation approach.Ethics and disseminationThis is a systematic review, so no patients will be directly involved in the design or development of this study. The findings from this systematic review will be disseminated to relevant patient populations and caregivers and will guide the WHO’s recommendations on formula consumption versus animal milk in infants aged 6–11 months.Trial registration numberCRD42020210925.
Image based analysis of meibomian gland dysfunction using conditional generative adversarial neural network
Authors: Khan Zakir Khan , Umar Arif Iqbal , Shirazi Syed Hamad , Rasheed Asad , Qadir Abdul , Gul Sarah 
Published: February 2021

ObjectiveMeibomian gland dysfunction (MGD) is a primary cause of dry eye disease. Analysis of MGD, its severity, shapes and variation in the acini of the meibomian glands (MGs) is receiving much attention in ophthalmology clinics. Existing methods for diagnosing, detection and analysing meibomianitis are not capable to quantify the irregularities to IR (infrared) images of MG area such as light reflection, interglands and intraglands boundaries, the improper focus of the light and positioning, and eyelid eversion.Methods and analysisWe proposed a model that is based on adversarial learning that is, conditional generative adversarial network that can overcome these blatant challenges. The generator of the model learns the mapping from the IR images of the MG to a confidence map specifying the probabilities of being a pixel of MG. The discriminative part of the model is responsible to penalise the mismatch between the IR images of the MG and confidence map. Furthermore, the adversarial learning assists the generator to produce a qualitative confidence map which is transformed into binary images with the help of fixed thresholding to fulfil the segmentation of MG. We identified MGs and interglands boundaries from IR images.ResultsThis method is evaluated by meiboscoring, grading, Pearson correlation and Bland-Altman analysis. We also judged the quality of our method through average Pompeiu-Hausdorff distance, and Aggregated Jaccard Index.ConclusionsThis technique provides a significant improvement in the quantification of the irregularities to IR. This technique has outperformed the state-of-art results for the detection and analysis of the dropout area of MGD.