bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling of Feature-Based Design Process
Authors: Gao Fei , Roller Dieter
Published: February 2021

Capturing design process is becoming an important topic of feature-based modeling, as well as in product data exchange, concurrent design, and cooperative design. Three critical issues on the modeling of design process are considered in this paper, namely, feature concepts, feature evolution, and the semantic consistencies of the states of product models. A semantics-based product model is introduced to facilitate the description of both conceptual and detailed models, and to maintain the semantic consistencies of product states. The process is represented by feature states and their evolution records. Feature type variation and prototype-based design are proposed to support feature evolution. A conceptual description of the design process and an example are given.
Managing Function Constraints in Design Sheet™
Authors: Reddy Sudhakar Y. , Fertig Kenneth W.
Published: February 2021

Design Sheet™ is a constraint management system specially designed for doing conceptual design cost and performance tradeoff studies. It represents the design models as constraints between design variables, and uses graph-theoretic algorithms to decompose large systems of nonlinear equations into smaller pieces that can be solved robustly. This paper describes extensions to Design Sheet that enable it to manage functions as variables in a constraint network. The paper also discusses the new capabilities of function encapsulation and explicit differentiation that are built on top of these extensions. The ability to encapsulate a part of the constraint network into a function, and use it in other constraints, promotes model reuse and improves computational efficiency. The capability to automatically differentiate certain variables with respect to other design variables allows Design Sheet to be used for solving practical optimization problems. In combination with the tradeoff capability, this enables the designer to track changing optima in trade studies. The paper also provides a couple of optimization examples to demonstrate these new capabilities.
Towards a Consistent Preference Representation in Engineering Design
Authors: Wan Jie , Krishnamurty Sundar
Published: February 2021

Multiattribute utility theory is commonly used to define and represent the decision-maker’s preferences under conditions of uncertainty and risk. A major issue in implementing this approach deals with the identification and generation of appropriate utility functions, especially in an often nonlinear and complex engineering design environment. Typically, the decision-maker’s preferences are provided through lottery questions rather than based on deductive reasoning to reflect the nonlinear tradeoffs among the attributes. The use of such an intuitive procedure can lead to inconsistent and inexact preference information that may result in inaccuracy and rank reversal problems. Alternatively, this paper presents an Interactive Preference-Modeling (IPM) method towards a consistent preference representation in engineering design. Focusing on the preference orientation by implicitly articulating the designer’s priorities, this method provides a methodical framework to check and eliminate inconsistency in preference information, and to accurately express preferences through rational pairwise comparisons. The development of IPM method and its utilization in the determination of the system utility function from a consistent set of local utility functions are presented in the context of a beam design problem and the results are discussed.
Modeling of Incomplete and Uncertain Information in Relational Database for Engineering Design and Production Management: Review and Future Work
Authors: Li Q. , Ma Z. M. , Zhang W. J.
Published: February 2021

The current engineering design and production management puts an essential requirement on information modeling and manipulation, i.e., the need to represent evolutionary information with engineering and production processes. Such a need requires dealing with so called incomplete and uncertain information, which will be discussed in this paper. The contribution of the paper includes an elaboration of the information soundness (in database). Based on this elaboration the need to represent incomplete and uncertain information is explained. The state of the art of the representation and the manipulation of incomplete and uncertain information in database is then shown in a relational database environment. This will also include the authors’ work. Finally, some ideas on future work are discussed, including an important observation, i.e., the need to study fuzzy probabilistic information.
Evaluation of a Mechanical Assembly Using Manual and Robotic Methods
Authors: Risbud Sameer , Jain Utkarsh , Vartak Amol , Soni A. H. , Gandhi Nilesh
Published: February 2021

This paper attempts to evaluate the assembly of a conventional paper dispenser using manual as well as robotic method. The main thrust of the paper is using the Boothroyd and Dewhurst DFA charts for the assembly evaluation and analysis and commenting critically on the effectiveness of the charts. Thus the paper presents a case study in the analysis of assemblies using Boothroyd and Dewhurst DFA charts.
Rule Based Number Synthesis for Kinematic Linkage Mechanism With Full Revolute Joints
Authors: Karunamoorthy Swami , Condoor Sridhar S.
Published: February 2021

Number synthesis is an important building block of type synthesis and it needs to be performed a priori to dimensional synthesis. The number synthesis methods available in the literature are not effective in predicting all possible linkage combinations. There is a need for a unified, yet simple, procedure to generate a complete list of Kinematic Link Set Solution (KLSS). An emphasis is given in this paper to develop such a method based on the analogy of isomers. It resulted in an easy procedure that is rule-based. The procedure is efficient in producing a linkage atlas for a given degree of freedom. A program is developed to generate the linkage atlas based on these rules. The results show that the rule-based approach is viable for pedagogical as well as industrial applications.
A New Approach Combining Numerical Analysis and Three Dimensional Simulation for Design of Worm Gearing With Preferable Localized Tooth Contact
Authors: Su D. , Yang F. , Gentle C. R. , Reith D.
Published: February 2021

A new approach has been developed for design of worm gear drives with preferable localised tooth contact (PLTC). The approach consists of numerical analysis and three-dimensional simulation within an advanced CAE package. The numerical analysis secures the localised contact, which provides mathematical models and a numerical calculation procedure to determine the modification parameters for the PLTC. With the three-dimensional simulation, the tooth contact pattern at any instant and the moving direction of the localised contact area can be predicted; moreover, the interference between the modified tooth surfaces can be detected, and, hence, it can be avoided at design stage. The simulation proves that the PLTC is much less sensitive to the errors arising from manufacturing and assembly, which is beneficial for achieving a high transmission quality and cutting down the time and efforts spent in production and assembly.
Introduction of Two-Link, In-Plane, Bistable Compliant MEMS
Authors: Jensen Brian D. , Howell Larry L. , Salmon Linton G.
Published: February 2021

A bistable mechanism has two stable states within its range of motion. Its advantages include the ability to stay in two positions without power input and despite small external disturbances. Therefore, bistable micro-mechanisms could allow the creation of MEMS with improved energy efficiency and positioning accuracy. This paper presents the first bistable MEMS which function within the plane of fabrication. These bistable mechanisms, known as “Young” bistable mechanisms, obtain their energy storage characteristics from the deflection of two compliant members, have two pin joints connected to the substrate, and can be constructed of two layers of polysilicon. The pseudo-rigid-body model overcomes problems with nonlinearities in the analysis and design of these mechanisms. This approach allows greater freedom and flexibility in the design process. Testing of the mechanisms demonstrated their bistable behavior and the repeatability of the stable positions.
Design of Electrostatic Micro Mirrors for Improved Stability Though Surface Contact
Authors: Moulton Timothy , Ananthasuresh G. K.
Published: February 2021

There exists a need to stabilize the electrostatic actuation commonly used in Micro-Electro-Mechanical Systems (MEMS). Most electrostatically actuated MEMS devices act as variable capacitors with varying gap between the charged conductors. Electrostatic force in these devices is a nonlinear attractive force between the conductors resulting in a complex dynamic system. These systems are stable for only a small portion of the initial gap. In this paper a design method is presented for electrostatic micro-mirrors with improved stability. Controllable, stable electrostatic actuation can be achieved through surface contact between the two conductors. Once in contact with the surface, the compliance of the structure is used to stabilize the electrostatic actuation over a long range of motion. Beam based variable angle mirrors were designed and fabricated using the Multi-User MEMS Process at MCNC technology center. The design methods for stable electrostatic actuation were tested on these mirrors. Some characteristics are noted and their implementation into future designs is discussed.
Experimental Analysis and Parameter Estimation for Mechanisms
Authors: Wang Deming , Beale David
Published: February 2021

The paper presents an experimental method to estimate dynamic parameters of general mechanisms. The signals of dynamic motion and external force of mechanisms were obtained by a piezo-electric accelerometer and a hammer force transducer. A set of linear dynamic parameter equations are derived from nonlinear motion equations and constraint equations of mechanisms to estimate the dynamic parameters of the system. The accuracy of the parameter estimation depends on the number of non-zero singular values and the condition number of the parameter equations. A typical four-bar linkage was taken as an example for accuracy analysis of the dynamic parameter estimation.
Analytical Model Method for Dynamics of N-Celled Tetrahedron-Tetrahedron Variable Geometry Truss Manipulators
Authors: Xu Li Ju , Li Hong , Fan Shou Wen
Published: February 2021

In this paper some fundamental formulae are derived for tetrahedron-based variable geometry truss manipulator which is composed of a series of tetrahedrons stacked upon each other such that one link in each cell is made variable on length. Analytical model for dynamics of the manipulator is established, and expressions in numeric-symbolic form of model matrices are derived. An example is given for illustration.
Lower-Pair Joint Geometry
Authors: Waldron Kenneth J.
Published: February 2021

This paper contains a geometrically based proof that the six lower pair joint types identified by Reuleaux are the only possible kinematic joints for which contact occurs solely over surfaces. The surface geometries for which line contact can occur and the relationship between the geometry of the contacting surfaces and the connectivity, or number of degrees of freedom of the joint is also discussed.
SphinxCAM: Computer-Aided Manufacturing for Spherical Mechanisms
Authors: Ketchel John S. , Larochelle Pierre M.
Published: February 2021

In this paper we present SphinxCAM, a computer-aided manufacturing software for spherical four-bar mechanisms. The kinematics of spherical mechanisms are reviewed as they pertain to their manufacture. This is followed by a brief review of some of the current computer-aided design (CAD) software for spherical four-bar mechanisms, e.g. Sphinx, SphinxPC, and Isis. These software packages provide the three-dimensional visualization and computational capabilities necessary to design spherical four-bar mechanisms. However, to date no tools exist to aid in the manufacture of spherical mechanisms. SphinxCAM, when used with the CAD tools mentioned above, facilitates the design, visualization, and manufacture of spherical four-bar mechanisms.
Screw Polygons, Finite Screws, and Biquaternions
Authors: Rico M. José María , Gallegos J. Victor , Duffy Joseph
Published: February 2021

In this contribution, the close relationship between screw polygons, finite screws, and biquaternions is elucidated. Further, it is shown that a reinterpretation of screw polygon problems in terms of biquaternions leads to a simple and straightforward solution of the direct problem of screw polygons. Moreover, the reintrepretation allows a simple solution of a pair of types of the inverse problem of screw polygons. As indicated by Mavroidis and Roth, these latter problems had not been previously reported in the literature.
Screw Theory and Helicoidal Fields
Authors: Gallardo A. Jaime , Rico M. José María
Published: February 2021

Chevallier [1991] regarded a screw as the geometric representation of a “helicoidal” field: i.e. a vector field with helicoidal properties. In this contribution, this identification is employed to develop a formal approach to systematically define “reduced acceleration state” and “reduced jerk state”. Furthermore, it is shown that the comparison of the velocity state, “reduced acceleration state” and “reduced jerk state” is sufficient to determine if a pair of infinitesimal motions of a rigid body are, or not, equal.
Displacement Analysis of Multi-Loop Mechanisms Using Gröbner Bases
Authors: Dhingra A. K. , Almadi A. N. , Kohli D.
Published: February 2021

The displacement analysis problem for planar mechanisms can be written as a system of algebraic equations, in particular as a system of multivariate polynomial equations. Elimination theory based on resultants and polynomial continuation are some of the methods which have been used to solve this problem. This paper explores an alternate approach, based on Gröbner bases, to solve the displacement analysis problem for planar mechanisms. It is shown that the reduced set of generators obtained using the Buchberger’s algorithm for Gröbner bases not only yields the input-output polynomial for the mechanism, but also provides comprehensive information on the number of closures and the relationships between various links of the mechanism. Numerical examples illustrating the applicability of Gröbner bases to displacement analysis of 10 and 12-link mechanisms and determination of coupler curve equation for 8-link mechanisms are presented.
Solving the Input/Output Problem for Planar Mechanisms
Authors: Nielsen James , Roth Bernard
Published: February 2021

This paper presents a method for solving the input/output problem for all planar mechanisms composed of revolute joints. The solution procedure is a modification of the Dixon resultant method, which was developed to solve sets of polynomial equations; in this paper the method is applied to sets of equations which are linear in the sines and cosines of unknown angles. A particular planar multi-circuit mechanism is analyzed to illustrate the solution procedure, and implementation details are discussed.
An Optimality Criteria Approach for the Topology Synthesis of Compliant Mechanisms
Authors: Saxena A. , Ananthasuresh G. K.
Published: February 2021

The physical insight used in formulating a multi-criteria optimization problem for the synthesis of compliant mechanisms, is quickly lost if mathematical programming techniques (SLP, SQP etc.) are used to determine the optimal solution. As opposed to the previous works that relied upon mathematical programming search techniques to find the optimum solution, in this paper we present an alternative method of solution called the optimality criteria method. Optimality criteria methods have proven to be effective in structural optimization problems with a large number of variables, and very few constraints as is the case in the topology synthesis of compliant mechanisms. The important new results of this paper include: (i) the derivation of a physically insightful optimal property of compliant mechanisms which states that the ratio of the mutual potential energy density and the strain energy density is uniform throughout the continuum (ii) the development of the optimality criteria method of solution in the form of a simple update formula for the design variables by using the above property (iii) design parameterization using the frame finite-element based ground-structure that appropriately accounts for the requisite bending behavior in the continuum, and (iv) numerical implementation of previously reported density based design parameterization using bilinear plane-stress elements. In addition, a new energy based multi-criteria objective function is presented to maximize the useful output energy (which is equivalent to maximizing the mechanical advantage) while meeting the kinematic requirements. Several examples are included to demonstrate the validity of the optimal property, the optimality-criteria method of solution, and the improvements made possible by the new energy based objective function.
Optimal Simultaneous Kinematic, Dynamic and Control Design of High Performance Manipulators Based on Trajectory Pattern Method
Authors: Rastegar J. , Liu L. , Mattice M.
Published: February 2021

An optimal simultaneous kinematic, dynamic and control design approach is proposed for high performance computer controlled machines such as robot manipulators. The approach is based on the Trajectory Pattern Method (TPM) and a fundamentally new design philosophy that such machines in general and ultra-high performance machines in particular must only be designed to perform a class or classes of motions effectively. In the proposed approach, given the structure of the manipulator, its kinematic, dynamic and control parameters are optimized simultaneously with the parameters that describe the selected trajectory pattern. In the example presented in this paper, a weighted sum of the norms of the higher harmonics appearing in the actuating torques and the integral of the position and velocity tracking errors are used to form the optimality criterion. The selected optimality criterion should yield a system that is optimally designed to accurately follow the specified trajectory at high speed. Other objective functions can be readily formulated to synthesize systems for optimal performance. The potentials of the developed method and its implementation for generally defined motion patterns are discussed.
A New Algorithm Based on Two Extra-Sensors for Real-Time Computation of the Actual Configuration of the Generalized Stewart-Gough Manipulator
Authors: Parenti-Castelli V. , Di Gregorio R.
Published: February 2021

It is well known that the direct position analysis of fully-parallel manipulators provides more than one solution, i.e., more than one configuration of the mechanism is possible for a given set of the actuated variables of motion. Extra information is, thus, necessary to find the actual configuration of the manipulator. This paper presents a new algorithm for the real-time computation of the actual configuration of the generalized Stewart-Gough manipulator, also known as 6-6 fully-parallel manipulator with general geometry. The proposed algorithm makes use of two extra rotary sensors in addition to the six normally implemented in the servosystems of the manipulator. A one-to-one correspondence between the sensor measurements and the manipulator configuration is provided. With respect to other algorithms recently presented in the literature, the proposed method greatly reduces the computational burden. Finally a case study shows the effectiveness of the proposed procedure.
A Gröbner-Sylvester Hybrid Method for Closed-Form Displacement Analysis of Mechanisms
Authors: Dhingra A. K. , Almadi A. N. , Kohli D.
Published: February 2021

The displacement analysis problem for planar and spatial mechanisms can be written as a system of multivariate polynomial equations. Elimination theory based on resultants and polynomial continuation are some of the methods which have been used to solve this problem. This paper presents a new approach to displacement analysis using the reduced Gröbner basis form of a system of equations under degree lexicographic (dlex) term ordering of its monomials and Sylvester’s Dialytic elimination method. Using the Gröbner-Sylvester hybrid approach, a finitely solvable system of equations F is transformed into its reduced Gröbner basis G using dlex term ordering. Next, using the entire or a subset of the set of generators in G, the Sylvester’s matrix is assembled. The vanishing of the resultant, given as the determinant of Sylvester’s matrix, yields the necessary and sufficient condition for the polynomials in G (as well as F) to have a common factor. The proposed approach appears to provide a systematic and rational procedure to the problem discussed by Roth (1994) dealing with the generation of (additional) equations for constructing the Sylvester’s matrix. Three examples illustrating the applicability of the proposed approach to displacement analysis of planar and spatial mechanisms are presented. The first and second examples deal with forward displacement analysis of the general 6-6 Stewart mechanism and the 6-6 Stewart platform, whereas the third example deals with the determination of the input-output polynomial of a 8-link 1-DOF mechanism which does not contain any 4-link loops.
Learning Control of a High-Speed Cam Dynamic System in the Presence of Viscous Damping and Coulomb Friction Theory and Experiment
Authors: Chew Meng-Sang , Wongratanaphisan Theeraphong , Lu Yi-Chen
Published: February 2021

This paper introduces the application of learning control theory to the intelligent control of an electromechanical cam-follower system. Learning control has been shown to handle inverse kinematics and inverse dynamics problems very well. It is a technique that can be applied to systems that perform repetitive tasks in order to reduce the errors that occur between the actual output and the desired output. Here, learning control is applied to a dynamic system containing nonlinear kinematics elements such as a cam. The learning process is based on output errors alone. It does not require explicit knowledge of the physical system. The presence of viscous damping and Coulomb friction both simplifies and challenges the learning control technique in compensating for such highly nonlinear dissipative effects within the cam-follower system. Results are presented based on the simulations of the system as well as the experiment. This study shows that learning control is capable of compensating for nonlinear Coulomb friction, that frequency occurs in the joints of many real world mechanisms.
Efficient Solution of Stiff ODE by Implicit Collocation Method
Authors: Pasic Hajrudin
Published: February 2021

When s-stage fully implicit collocation method is used to solve n–dimensional system of implicit ordinary differential equations (ODE) f(x, y, y’) = 0 the resulting algebraic system has a dimension sn. Its solution by Gauss elimination is expensive and requires s3n3 / 3 operations. In this paper we present an efficient algorithm which uncouples the algebraic system into a block-diagonal matrix with sn-dimensional blocks that may be solved in parallel. It applies to both explicit and implicit ODEs. The algorithm is formally different from the implicit Runge-Kutta (RK) method in that the solution for y is assumed to have a form of an algebraic polynomial whose coefficients are found by enforcing y to satisfy the differential equation at the collocation points. Locations of the collocation points are found from the derived stability function such as to guarantee both good stability and precision properties. Such a procedure leads to an algebraic system which has a sparse block-form and which may be easily diagonalized, providing an efficient solution of the problem, which is about s2 times faster than the Gauss elimination applied to the original, nondiagonalized system. In addition, the block-diagonal form of the algebraic system allows parallel processing and further increase of efficiency.
Error Transfer of Planar Linkages With Pair Clearance: Part 2 — The Effect of Dimension Type to the Error Transfer Coefficient
Authors: Li Song , Xianmin Zhang , Jian Yang
Published: February 2021

In this paper, based upon the method of Part 1, by the Monte-Carlo simulative experiment and the method of multivariate linear regression, the general regression equation of the planar linkage’s error transfer coefficient (ETC) for pair clearance is presented. And the regression equation is developed to display the effect of the driver relative length to ETC while the pair fit is invariable. The studying result shows that the regression equation of the effect of the driver’s relative length to ETC has the same form while the dimension type is variable. And through the curves, the effect of the dimension type to ETC and the output motion standard deviation of the mechanism is shown.
Natural Frequency Spectra and Vibration Modes of Planetary Gears
Authors: Lin Jian , Parker Robert G.
Published: February 2021

This work develops an analytical model of planetary gears and uses it to investigate their natural frequencies and vibration modes. The model admits three planar degrees of freedom for each of the sun, ring, carrier and planets. It includes key factors affecting planetary gear vibration such as gyroscopic effects, time-varying stiffness, and static transmission error excitation. For the linear time-invariant case, examination of the associated eigenvalue problem reveals the well-defined structure of the vibration modes, where the special structure results from the cyclic symmetry of planetary gears. Vibration modes are classified into rotational, translational and planet modes. The unique characteristics of each type of mode are analytically investigated in detail. For each class of mode, reduced-order eigenvalue problems are derived. The modal strain energy distributions are also discussed.
A Simple Method for Gear Ratio and Torque Analysis of Planetary Train Systems
Authors: Zhang Yi , Wu Zhi
Published: February 2021

Planetary gear train systems are widely used in automotive transmissions due to their compactness, large reduction ratios and degrees of freedom available for the selection of gear ratios. The analysis of gear ratios and torque relations among the elements of a planetary train system is often difficult due to the complexity of the planetary train structure. This is especially the case for automotive transmissions using planetary train system where the members for input and output and the members that are fixed or interconnected must be changed in the clutch engagement schedule to obtain multiple transmission speeds. This paper proposes a systematic approach that simplifies the gear ratio and torque analysis based on the basic planetary train characteristics. The approach can be effectively used for the analysis of gear ratio and static torques for power transmissions consisting of parallel planetary trains. A case study of multi-speed automotive transmission based on the approach is included in the paper.
Detecting Gear Tooth Breakage Using Acoustic Emission: A Feasibility and Sensor Placement Study
Authors: Singh Avinashchandra , Houser Donald R. , Vijayakar Sandeep
Published: February 2021

Vibration and debris monitoring methods are being increasingly used to detect gear tooth breakage. In this paper an alternate method of detecting gear tooth cracking is investigated. It is based on the phenomenon of acoustic emission (AE). The detectability of growing cracks using AE is established. Before this method can be used to detect crack growth in real systems, the transmissibility of these waves has to be studied. These waves have to propagate across a number of mechanical interfaces as they travel from the source to the sensor. The loss in strength of these waves at various interfaces commonly encountered in mechanical systems is studied in this paper.
Completing Wallace's journey
Authors: Kennedy Jonathan D. , Fjeldså Jon
Published: February 2021

A global inventory of species diversity is critical for understanding the evolution of life on Earth
Supplemental Material: Two key switches in regional stress field during multi-stage deformation in the Carboniferous–Triassic southernmost Altaids (Beishan, NW China): Response to orocline-related roll-back processes
Authors: Tian Zhonghua , Xiao W.J. , al. et
Published: February 2021

Table S1: (STS1) Samples collected near the study area; Table S2: Sample information from the shear zone and mélange zone: Table S3: (1) U-Pb isotope dates of magmatic zircons in granitic mylonites (11HYJ02 and 11QJJ01) from the Huoshishan ophiolitic mélange and the Qijiaojing shear zone. See Figure 2 for sample locations, (2) 40Ar/39Ar step-heating results of muscovites and biotite in granitic mylonites (11QJJ01, 11HYJ02, 11HYJ01-2, 11HYJ04 and 10TZHD03) from the Hongyangjing shear zone, the Huoshishan ophiolitic mélange, and the Qijiaojing shear zone. See Figure 2 for sample locations, (3) Methods：Methods divide into analytical method-EBSD (Electron backscatter diffraction), analytical method-U-Pb age dating, analytical method- 39Ar-40Ar age dating; Table S4. the raw data of 40Ar/39Ar from Institute of Geology and Geophysics, Chinese Academy of Science (IGGCAS) are given in the Supplementary data Table S4.
Exploring the operationalisation and implementation of outreach in community settings with hard-to-reach and hidden populations: protocol for a scoping review
Authors: Krabbe Janina , Jiao Sunny , Guta Adrian , Slemon Allie , Cameron Aman Ahluwalia , Bungay Vicky
Published: February 2021

Introduction

Outreach is regularly identified as an effective strategy to engage underserved, hard-to-reach and hidden populations with essential life-sustaining health services. Despite the increasing expansion of outreach programmes, particularly in HIV prevention and health promotion with youth, sex workers, people living with mental health and substance use challenges, and those affected by homelessness, there has been limited synthesis of the evidence concerning the core components of outreach programming or indicators of its successful implementation. Without this understanding, current outreach programmes may be limited in achieving the desired aims. The aim of this scoping review is to explore how outreach has been operationalised and implemented in various community settings with people underserved in current healthcare contexts. Understanding the state of knowledge pertaining to outreach as programming and as practice involving the engagement of people considered hard-to-reach will enable the identification of promising trends and limitations in the field.

Methods and analysis

This scoping review follows the Arksey and O’Malley’s framework. CINAHL, MEDLINE, PsycINFO and PubMed databases will be searched for peer-reviewed references focused on outreach with hard-to-reach and hidden groups from 1 January 2008 to 30 April 2020. Guided by explicit inclusion and exclusion criteria, three reviewers will independently assess references in two successive stages. Titles and abstracts will be reviewed followed by full-text assessment of papers meeting the review criteria. A descriptive overview, tabular and/or graphical summaries and a thematic analysis will be carried out on extracted data.

Ethics and dissemination

Ethics approval was not required as the only data source was peer-reviewed documents. Outreach knowledge users who are members of the project team will participate in all aspects of study design, implementation and result dissemination strategies.
Evaluation of the efficacy and impact of a clinical prediction tool to identify maltreatment associated with children’s burns
Authors: Hollen Linda , Bennett Verity , Nuttall Dianne , Emond Alan M , Kemp Alison
Published: February 2021

Background

An estimated 10%–24% of children attending emergency departments with a burn are maltreated.

Objective

To test whether a clinical prediction tool (Burns Risk assessment for Neglect or abuse Tool; BuRN-Tool) improved the recognition of maltreatment and increased the referral of high-risk children to safeguarding services for assessment.

Methods

A prospective study of children presenting with burns to four UK hospitals (2015–2018), each centre providing a minimum of 200 cases before and after the introduction of the BuRN-Tool. The proportions of children referred to safeguarding services were compared preintervention and postintervention, and the relationship between referral and the recommended cut-off for concern (BuRN-Tool score (BT-score) ≥3) was explored.

Results

The sample was 2443 children (median age 2 years). Nurses and junior doctors mainly completed the BuRN-Tool, and a BT-score was available for 90.8% of cases. After intervention, 28.4% (334/1174) had a BT-score ≥3 and were nearly five times more likely to be discussed with a senior clinician than those with a BT-score <3 (65.3% vs 13.4%, p<0.001). There was no overall difference in the proportion of safeguarding referrals preintervention and postintervention. After intervention, the proportion of referrals for safeguarding concerns was greater when the BT-score was ≥3 (p=0.05) but not for scores <3 (p=0.60). A BT-score of 3 as a cut-off for referral had a sensitivity of 72.1, a specificity of 82.7 and a positive likelihood ratio of 4.2.

Conclusions

A BT-score ≥3 encouraged discussion of cases of concern with senior colleagues and increased the referral of <5 year-olds with safeguarding concerns to children’s social care.
Physiotherapy in palliative medicine: patient and caregiver wellness
Authors: Bernabeu-Wittel Máximo , Moreno-Gaviño Lourdes , Nieto-Martín Dolores , Lanseros-Tenllado Julia , Sáenz-Santamaría Ana , Martínez-Pérez Olga , Aguilera-Gonzalez Carmen , Pereira-Domínguez Manuel , Ollero-Baturone Manuel
Published: February 2021

Objectives

Despite the demonstrated efficacy of physiotherapy in palliative care programmes, there are scarce data of its real-life impact on patients’ and caregivers’ wellness and stress. Our aim was to assess effectiveness of a 30-day physiotherapy programme in psychological wellness and health-related quality of life (HRQoL) of patients with advanced chronic diseases or cancer and in their caregivers’ stress.

Methods

Quasiexperimental before–after study applying personalised kinesitherapy, exercise with curative effects, respiratory physiotherapy, therapeutic massages and ergotherapy. Psychological wellness, HRQoL and caregiver’s strain outcomes were measured.

Results

207 patients (60% men, with a mean age of 73.6±12 years) were included; 129 (62.3%) with advanced cancer, and the remaining 78 with advanced chronic diseases. Psychological wellness (Emotional Stress Detection Tool decreased from 12.4±3 to 11±3; p<0.0001), caregiver’s strain (Caregiver Strain Index decreased from 8.5±3.2 to 7.9±3.5; p<0.0001) and HRQoL (WHO-BREF physical health domain increased from 8.3±2.6 to 9.4±2.9; p<0.0001) showed a significant improvement after the physiotherapy programme. Global satisfaction with the physiotherapy intervention was also high (Client Satisfaction Questionnaire-8 of 28.3±3.3 points).

Conclusions

A personalised physiotherapy programme incorporated to integral palliative care improved psychological wellness, HRQoL and caregivers’ strain of patients with advanced chronic diseases and cancer.
Contraceptive dynamics during COVID-19 in sub-Saharan Africa: longitudinal evidence from Burkina Faso and Kenya
Authors: Karp Celia , Wood Shannon N , Guiella Georges , Gichangi Peter , Bell Suzanne O , Anglewicz Philip , Larson Elizabeth , Zimmerman Linnea , Moreau Caroline
Published: February 2021

Introduction

Evidence from health emergencies suggests COVID-19 will disrupt women’s sexual and reproductive health (SRH). In sub-Saharan Africa, which experiences the highest rates of unintended pregnancy and unsafe abortion globally, COVID-19 is projected to slow recent progress toward universal access to contraceptive services.

Methods

We used longitudinal data collected from women at risk of unintended pregnancy in Burkina Faso (n=1186) and Kenya (n=2784) before (November 2019–February 2020) and during (May–July 2020) COVID-19 to quantify contraceptive dynamics during COVID-19; examine sociodemographic factors and COVID-19 experiences related to contraceptive dynamics; and assess COVID-19-related reasons for contraceptive non-use. Bivariate and multivariate logistic regressions were used to examine correlates of contraceptive dynamics amid COVID-19.

Results

Most women did not change their contraceptive status during COVID-19 (68.6% in Burkina Faso and 81.6% in Kenya) and those who did were more likely to adopt a method (25.4% and 13.1%, respectively) than to discontinue (6.0% and 5.3%, respectively). Most women who switched contraceptives were using methods as or more effective than their pre-pandemic contraception. Economic instability related to COVID-19 was associated with increased contraceptive protection in Burkina Faso but not in Kenya. Altogether, 14.4% of non-contraceptive users in Kenya and 3.8% in Burkina Faso identified COVID-19-related reasons for non-use.

Conclusions

The vast majority of women at risk of unintended pregnancy did not change their contraceptive status during COVID-19, and more women adopted than discontinued methods. A minority of women reported COVID-19-related reasons for non-use, underscoring the importance of expanding safe modes of service delivery during health crises.
Assessment of SLE activity for acute clinical decision-making: use of a colour-coded threat-level approach for the non-rheumatologist
Authors: Flower Cindy
Published: February 2021

Systemic lupus erythematosus (SLE) activity indices are widely applied in academic centres and for research protocols but are often not part of usual care in busy under-resourced clinical settings especially where non-rheumatologists are involved in SLE management. We developed a simplified activity index based on the established knowledge and experience of SLE in our hospital and further applied a treatment guideline to assist in acute clinical decision-making. The index is colour-coded for easy reference and categorizes clinical complications in order of the severity of the threat they pose to the patient. An index such as this can be modified to have wider application and relevance in other countries with reduced access to specialist care.
Asphalt pavement friction coefficient prediction method based on genetic-algorithm-improved neural network (GAI-NN) model
Authors: Sun Zhaoyun , Hao Xueli , Li Wei , Huyan Ju , Sun Hongchao
Published: February 2021

To overcome the limitations of pavement skid resistance prediction using the friction coefficient, a genetic-algorithm-improved neural network (GAI-NN) was developed in this study. First, three-dimensional (3D) point-cloud data of an asphalt pavement surface were obtained using a smart sensor (Gocator 3110). The friction coefficient of the pavement was then obtained using a pendulum friction tester. The 3D point-cloud dataset was then analyzed to recover the missing data and perform denoising. In particular, these data were filled using cubic spline interpolation. Parameters for texture characterization were defined, and methods for computing the parameters were developed. Finally, the GAI-NN model was developed by modifying the weights and thresholds. The test results indicated that using pavement surface texture 3D data, the GAI-NN was capable of predicting the pavement friction coefficient with sufficient accuracy, with an error of 12.1%.
Seed treatment and N rate do not impact dry bean (Phaseolus vulgarisL.) plant growth or grain yield in Ontario
Authors: Boersma Stephen J. , Gillard Chris L.
Published: February 2021

Application of nitrogen fertilizer and commercial seed treatments are two strategies dry bean growers in Ontario utilize to manage root rot and maximize yields. However, data solidifying these practices is absent or outdated. Experiments were conducted at the Huron Research Station, near Exeter, Ontario, from 2008 to 2010, to measure plant growth and yield responses for navy, kidney, and cranberry dry bean market classes (cv. T9905, Pink Panther, and Etna, respectively) to seed treatment (NST, no seed treatment; CMBD, Cruiser Maxx Bean + Dynasty) and N fertilizer rates of 0, 35, 70, 105, 140, and 175 kg N·ha−1. Plant measurements taken included plant emergence, vigour, height and maturity, plant and seed mass, and grain moisture and yield. Over three years, plant growth and yield responses to seed treatment and nitrogen fertilizer were very scarce. Plant emergence and vigour either improved or were not affected by seed treatment or N rate, while increasing N rates increased plant height of only Pink Panther in 2008. Plant mass was unaffected by either factor while seed treatment decreased days to maturity and grain moisture of T9905 in 2008. Nitrogen fertilizer improved the grain yield of Etna, with the highest yields occurring with 70 kg N·ha−1or more, while other cultivar site–years did not respond. Overall, these results demonstrate dry beans rarely respond to N fertilizer or seed treatment at the Huron Research Station. Additional testing over multiple years and locations would assist in predicting these responses.
Gravitational redshift/blueshift of light emitted by geodesic test particles, frame-dragging and pericentre-shift effects, in the Kerr–Newman–de Sitter and Kerr–Newman black hole geometries
Authors: Kraniotis G. V.
Published: February 2021

We investigate the redshift and blueshift of light emitted by timelike geodesic particles in orbits around a Kerr–Newman–(anti) de Sitter (KN(a)dS) black hole. Specifically we compute the redshift and blueshift of photons that are emitted by geodesic massive particles and travel along null geodesics towards a distant observer-located at a finite distance from the KN(a)dS black hole. For this purpose we use the killing-vector formalism and the associated first integrals-constants of motion. We consider in detail stable timelike equatorial circular orbits of stars and express their corresponding redshift/blueshift in terms of the metric physical black hole parameters (angular momentum per unit mass, mass, electric charge and the cosmological constant) and the orbital radii of both the emitter star and the distant observer. These radii are linked through the constants of motion along the null geodesics followed by the photons since their emission until their detection and as a result we get closed form analytic expressions for the orbital radius of the observer in terms of the emitter radius, and the black hole parameters. In addition, we compute exact analytic expressions for the frame dragging of timelike spherical orbits in the KN(a)dS spacetime in terms of multivariable generalised hypergeometric functions of Lauricella and Appell. We apply our exact solutions of timelike non-spherical polar KN geodesics for the computation of frame-dragging, pericentre-shift, orbital period for the orbits of S2 and S14 stars within the$$1^{\prime \prime }$$1″of SgrA*. We solve the conditions for timelike spherical orbits in KN(a)dS and KN spacetimes. We present new, elegant compact forms for the parameters of these orbits. Last but not least we derive a very elegant and novel exact formula for the periapsis advance for a test particle in a non-spherical polar orbit in KNdS black hole spacetime in terms of Jacobi’s elliptic function sn and Lauricella’s hypergeometric function$$F_D$$FD.
Connecting and linking neurocognitive, digital phenotyping, physiologic, psychophysical, neuroimaging, genomic, & sensor data with survey data
Authors: Knott Charles E. , Gomori Stephen , Ngyuen Mai , Pedrazzani Susan , Sattaluri Sridevi , Mierzwa Frank , Chantala Kim
Published: February 2021

Combining survey data with alternative data sources (e.g., wearable technology, apps, physiological, ecological monitoring, genomic, neurocognitive assessments, brain imaging, and psychophysical data) to paint a complete biobehavioral picture of trauma patients comes with many complex system challenges and solutions. Starting in emergency departments and incorporating these diverse, broad, and separate data streams presents technical, operational, and logistical challenges but allows for a greater scientific understanding of the long-term effects of trauma. Our manuscript describes incorporating and prospectively linking these multi-dimensional big data elements into a clinical, observational study at US emergency departments with the goal to understand, prevent, and predict adverse posttraumatic neuropsychiatric sequelae (APNS) that affects over 40 million Americans annually. We outline key data-driven system challenges and solutions and investigate eligibility considerations, compliance, and response rate outcomes incorporating these diverse “big data” measures using integrated data-driven cross-discipline system architecture.
Erratum: Fibers of word maps and the multiplicities of non-abelian composition factors
Authors: Bors Alexander
Published: February 2021

We discuss two corrections concerning the paper mentioned in the title. One of them pertains to a slight error in a statement from a different paper that was used. For this statement, it is explained how to fix it and why this does not affect the correctness of our results. The other is concerned with an error in the original GAP source code used to verify some of our results. This error, which was subsequently fixed, did affect the correctness of one of our main theorems, which is now given in corrected (and stronger) form.
A
egis
+
Authors: Sikder Amit Kumar , Babun Leonardo , Uluagac A. Selcuk
Published: February 2021

The introduction of modern Smart Home Systems (SHSs) is redefining the way we perform everyday activities. Today, myriad SHS applications and the devices they control are widely available to users. Specifically, users can easily download and install the apps from vendor-specific app markets, or develop their own, to effectively implement their SHS solutions. However, despite their benefits, app-based SHSs unfold diverse security risks. Several attacks have already been reported to SHSs and current security solutions only consider smart home devices and apps individually to detect malicious actions, rather than the context of the SHS as a whole. Thus, the current security solutions applied to SHSs cannot capture user activities and sensor-device-user interactions in a holistic fashion. To address these limitations, in this article, we introduce A
egis
+, a novel context-aware platform-independent security framework to detect malicious behavior in an SHS. Specifically, A
egis
+ observes the states of the connected smart home entities (sensors and devices) for different user activities and usage patterns in an SHS and builds a contextual model to differentiate between malicious and benign behavior. We evaluated the efficacy and performance of A
egis
+ in multiple smart home settings (i.e., single bedroom, double bedroom, duplex) and platforms (i.e., Samsung SmartThings, Amazon Alexa) where real users perform day-to-day activities using real SHS devices. We also measured the performance of A
egis
+ against five different malicious behaviors. Our detailed evaluation shows that A
egis
+ can detect malicious behavior in SHS with high accuracy (over 95%) and secure the SHS regardless of the smart home layout and platforms, device configurations, installed apps, controller devices, and enforced user policies. Finally, A
egis
+ yields minimum overhead to the SHS, ensuring effective deployability in real-life smart environments.