bluuebunny/crossref_metadata_2025 huggingface dataset:
A Study on Active Dynamic Absorber
Authors: Seto Kazuto , Furuishi Yoshirou
Published: April 2021

Although it is known that active dynamic absorbers are useful for controlling vibration of structures, the design method for popular usage has not yet been established. This paper proposes the design method of the active dynamic absorber by use of the LQ optimum control theory. First, nondimensional representation of the state equation of the structure and active dynamic absorber system, the state feedback gain matrix, and the weight matrix, respectively, are constructed to obtain a generality. Secondly, the relationship between the vibration control effect and parameters of the weighting matrix are made clear for designing. The design data are prepared as the nondimensional root locus, frequency response, and impulse response charts. Effectiveness of the active dynamic absorber designed through the method is demonstrated experimentally.
Flexural Vibration Response of Beams With General Boundary Conditions: A Transfer Matrix Approach
Authors: Önsay T.
Published: April 2021

The wave-mode representation is utilized to obtain a more efficient form to the conventional transfer matrix method for bending vibrations of beams. The proposed improvement is based on a phase-variable canonical state representation of the equation governing the time-harmonic flexural vibrations of a beam. Transfer matrices are obtained for external forces, step-change of beam properties, intermediate supports and for boundaries. The transfer matrices are utilized to obtain the vibration response of a point-excited single-span beam with general boundary conditions. The general characteristic equation and the transfer mobility of a single-span beam are determined. The application of the analytical results are demonstrated on physical structures with different boundary conditions. A hybrid model is developed to incorporate measured impedance of nonideal boundaries into the transfer matrix method. The analytical results are found to be in excellent agreement with experimental measurements.
Experimental Research on Longitudinal Wave Velocity of Fiber Glass Rod and its Internal Viscous Damping
Authors: Hu Yu-Ren , Xu Jun
Published: April 2021

Fiber glass rod (i.e. FGR) is an uniaxial fiber reinforced plastic. In the movement of the rods, some dynamic characteristics such as the wave velocity and the damped coefficient are most important dynamic factors in analysis of the dynamic response of the rods. Generally, FGR are composed of two materials, fibers and resins. The particularities of the parameters for the wave velocity, etc of FGR are mainly depend on these two materials of different properties. This paper studies longitudinal velocity for FGR theoretecally and measure it by vibration method. The viscous damped coefficient is also measured by the theory of viscoelasticity. This paper presents that the viscous damped characteristic of material is mainly depend on the coupling mass between the rods.
Vibration Isolation in a Microgravity Environment
Authors: Alexander Richard M. , Gerhold Carl H. , Atwood Clay B. , Cordera Joseph F.
Published: April 2021

Many in-space research experiments require the microgravity environment attainable near the center of mass of the proposed Space Station. Since dynamic disturbances to the surrounding structure may undermine an experiments validity, isolation of these experiments is imperative. Analytical and experimental work has been completed in developing an isolation system which allows the payload to float freely within a prescribed boundary while being kept centered with forces generated by small jets of air. An experimental setup was designed and constructed to simulate the microgravity environment in the horizontal plane. Results demonstrate the air jet control system to be effective in managing payload oscillatory response. An analytical model was developed and verified by comparing predicted and measured payload response. The mathematical model is used to predict dynamic payload response to disturbances likely to be present in the Space Station.

The figure shown below is a schematic of the test setup to be discussed during the presentation.
Three-Schema Implementation in STEP: Standard for the Exchange of Product Model Data
Authors: Yang Yuhwei
Published: April 2021

This paper describes the development architecture of the evolving international product data standard, PDES/STEP. The focus of the paper is to present the influence of the three-schema concept and its implementation in STEP.

The fundamental requirement for any specification to be useful is that it must support its intended applications. PDES/STEP, as the future industry standard for product data communication, must be structured to provide flexibility to allow different implementation scenarios, e.g., sequential file exchange or controlled access of shared database implementations. In order to provide this required implementation flexibility, STEP is currently developed with an architecture that facilitates multiple specifications.

The STEP Integrated Architecture organizes both the resource models and models of the STEP Application Protocols. The STEP Integration Architecture presents an implementation that resembles elements of the ANSI/SPARC recommended three-schema model.
A PDES Model for Microwave Modules
Authors: Bahadur Sudhanshu , Harhalakis George , Hosier Robert N. , Minis Ioannis
Published: April 2021

This paper presents a novel application of the Layered Electrical Product (LEP) model of the PDES (Product Data Exchange specification using STEP) standard. All three levels of the LEP model are developed for a typical microwave module (MWM). The latter is comprised of a component layer, the artwork, an insulation layer and a ground plane, which is a complex mechanical part. The nature of the ground plane necessitated the enhancement of the first level of the model to include three-dimensional topological entities. Consequently, although the artwork and insulation layers are represented in two-and-a-half dimensions, (which is common practice in the case of Printed Wiring Boards), the ground plane is modeled using the three-dimensional PDES Geometrical and Topological models and the Form Features model. Level II includes the electrical entities of the MWM. New conventions that are necessary to represent particular features of the MWM have been proposed and applied. Based on the intention of PDES, design information that is closely related to manufacturing concerns has been represented in Level III of the model. Both the proposed structure and the contents of this level for MWMs are presented. Material specifications, mechanical features and design specifications for the manufacture of joins are included. Finally, potential applications of the LEP model and especially of Level III in automated process planning and producibility assessment are discussed.
Designing an Engineering Database for Telephone Networks
Authors: Danielson Scott G.
Published: April 2021

An engineering database modeling telephone outside plant networks is developed. Semantic and relational database design methodologies are used with the semantic data model developed based on an extended entity-relationship approach. This logical model is used to generate a normalized relational data structure. This database holds engineering data supporting engineering analyses, engineering work order generation procedures, and network planning activities. The database has been linked to separate network analysis programs and CAD-based network maps by a database application.
A Computer-Aided Analysis System With DBMS Support for Fiber-Reinforced Thick Composite Materials
Authors: Spainhour Lisa K. , Rasdorf William J. , Patton Edward M. , Burns Bruce P. , Collier Craig S.
Published: April 2021

The broad scope of the research described herein is the integration of several components of engineering software using a relational database. More specifically, a conceptual finite element material preprocessing system for fiber-reinforced composite materials was studied. In this computer-aided analysis (CAA) system, a materials database is integrated with several software components, including commercially available finite element analysis (FEA) programs and preprocessors, and tools for the design of laminated composite materials.

The focus of the system is on the integration of two- and three-dimensional composite materials data into several finite element analysis programs. Particular attention is given to analysis and design of components and structures using thick composite materials. Many engineering applications exist for thick composite structures; however, they have received less critical attention than the thin composite structures often used in aerospace applications. The primary objective of the composites analysis system is to enhance data transfer between and interaction among several engineering software programs with a minimum of user interaction.

This paper describes a specific implementation of a computer-aided analysis system that achieves this objective, detailing the need for the system and describing each of its components, including a composite materials database. The capabilities of the integrated system are discussed, including tasks such as composite laminate design, data entry, report generation, and interface file generation, performed in support of the finite element analysis capability. A major focus of the paper is on the twofold role of the materials database in the analysis system, as both a passive data repository and as a dynamic data transfer mechanism. The use of interface programs and direct integration techniques are discussed in the context of passing materials data between the user and the database, and between the database and the various system components or application programs.
The Contribution of Data Modeling to the Future Development of CAD/CAM Databases
Authors: Eastman Charles M.
Published: April 2021

Data modeling is proposed as a means to address the complexities of CAD/CAM databases. The distinctions between product data models and those in general databases are reviewed. A data model, called EDM, is presented that incorporates features that are defined to response to these differences. A review is given of data modeling analyses carried out thus far regarding database extensibility, including support for open-ended knowledge domains.
Product Data Management and Supporting Infrastructure for an Enterprise
Authors: Sheth Sharad
Published: April 2021

Global competition challenges engineering and manufacturing enterprises to shorten product development cycles, while meeting more stringent quality and cost objectives. In addition, product design and manufacturing methodologies are more complex, encompassing a complicated integration of electronic, mechanical, optical, and other subsystems.
CIM Dictionaries: An Evolutionary Approach to CIM Data Integration
Authors: Weissflog Uwe
Published: April 2021

This paper provides an overview of methods and ideas to achieve data integration in CIM. It describes a dictionary approach allowing participating applications to define their common constructs gradually as an additional service across application systems. Because of the importance of product definition data, the role of PDES/STEP as part of this dictionary approach is also described.

The technical concepts of the dictionary, such as schema mapping, semantic data model, user methods and the required additions within participating applications are explained. Problems related to data integrity, data redundancy, performance and binding of dissimilar software components are discussed as well as the deficiencies related to today’s data modelling capabilities.

The added value an active dictionary can provide to a CIM environment consisting of established applications in heterogeneous environments, where migration into one standardized homogeneous set of CIM applications is not likely, is also explained.
Using Information Theory to Model Design Processes Supported by Information Systems
Authors: Rangan Ravi M.
Published: April 2021

This paper describes the use of information theory to model the interactions between various design agents in a design/manufacturing organization. In typical multidisciplinary design environments, the design attribute space is constrained by the requirements and compatibility conditions introduced by interacting disciplines. A key factor toward efficient design lies in the recognition of this constrained design space, and in communicating this to the designers during the initial stages of the design process. As a result, engineering information systems that support the multidisciplinary design activities must incorporate these constraints, and provide designers with a uniform mechanism that will assist design attribute awareness, provide decision discriminators and model design attribute dependencies.

The concept of entropy as defined in information theory will be used to quantify both the information content of a design as well as the design attribute space. Specifically, we shall investigate how this model may be used for a class of parametric design problems.
Adding Prolog Rules and OOPs Inheritance to Legacy Databases
Authors: Goldschmidt Art , Gangopadhyay Dipayan
Published: April 2021

We present a viable approach to add rules capability or object orientation to legacy databases.

Using a combination of language compilation, run-time trigger mechanisms and inter-language call facility, we integrate an object-oriented logic programming language, called OOLP, with an existing CIM Database System Product, IBM’s CIM CDF.

The result is a system that provides storage management of complex objects, rule-based validation, object oriented knowledge modelling and declarative query capability.
A Development Environment for Intelligent Feature Based Mechanical Design
Authors: Jayasuriya M. J. K. , Thompson J. G. , Krishnaswami P.
Published: April 2021

The modeling power of most mechanical CAD systems is limited to the creation and manipulation of topologically correct solids. Due to the lack of consideration for conceptual modeling, certain knowledge associated with a part design is either not captured, or its representation is incomplete. This inhibits the automation of subsequent analysis applications such as process planning. Furthermore, the software architectures of these CAD systems are designed primarily to serve the role of computer aided drafting. Consequently, these design environments fail to participate in the actual design process associated with mechanical part design.

This paper describes an effort directed towards designing and implementing a productive software development environment for intelligent mechanical design and manufacturing clients. The kernel of the system provides various functionalities to facilitate the development of these clients. These facilities emphasize the ability of each client to contribute and utilize knowledge that is essential for their successful operation. The development of such a knowledge based computing environment benefits from the work done in data modeling, semantic data modeling and knowledge representation. In this context, the utilization of the functional data model is demonstrated through a comprehensive example. A brief discussion on implementation of certain kernel functionality is included.
Data Base Requirements for Concurrent Design Systems
Authors: Vujosevic Ranko , Kusiak Andrew
Published: April 2021

The data base requirements for concurrent design systems are discussed. An object-oriented data base, which allows for definition of complex objects, specification of relationships between objects, and modular expandability without affecting the existing information is defined. The data base is developed based on the object-oriented data model implemented in Smalltalk-80. An assumption-based truth maintenance system for maintaining the dependency relationships between design and manufacturing information is described.
A Multimedia Concept Database for Improved Life Cycle Design
Authors: Bradley Stephen R. , Agogino Alice M.
Published: April 2021

The architecture of a multimedia conceptual design aid, the Concept Database, is presented. The goal of the Concept Database is to provide design teams with easy access to information about life cycle design issues for competing design concepts and access to relevant past designs. The architecture builds on our previous experience in developing the multimedia design archival system called Design SCRIBE (Structured Capture and Retrieval Information Base for Engineering Design.) Approaches to selectively retrieving descriptions of design concepts and past designs are summarized.
Integrating CAD/CAM
Authors: Ziarati R.
Published: April 2021

Many progressive companies have adopted Computer Integrated Manufacturing (CIM) strategy by interfacing drawing and design (CAD), manufacturing (CAM), production planning and Control (PPC, MRPII), inspection and customer services as well as business and management processes. This paper concentrates on aspects of integrating CAD with CAM and offers an example of how CAD information can be transformed into CAM data for given manufacturing operations.

The paper pays special references to the basis of many CAD and CAM systems and offers an integrated system which uses a single data base to produce the manufacturing files required enabling the costing based on materials used and manufacturing processes required as well as inspection processes and marketing requirements to be carried out.
Simplified Aerodynamic Loading Model for Non-Production Conditions for Floating Wind Systems Design
Authors: Alexandre Armando , Antonutti Raffaello , Gentils Theo , Mutricy Laurent , Weyne Pierre
Published: April 2021

Floating wind is now entering a commercial-stage, and there are a significant number of commercial projects in countries like France, Japan, UK and Portugal. A floating wind project is complex and has many interdependencies and interfaces. During all stages of the project several participants are expected to use a numerical model of the whole system and not only the part the participant has to design. Examples of this are the mooring and floater designer requiring a coupled model of the whole system including also the wind turbine, the operations team requiring a model of the system to plan towing and operations. All these stakeholders require a coupled model where the hydrodynamics, aerodynamics and structural physics of the system are captured with different levels of accuracy.

In this paper, we will concentrate on a simplified model for the aerodynamic loading of the turbine in idling and standstill conditions that can be easily implemented in a simulation tool used for floater, mooring and marine operations studies.

The method consists of using a subset of simulations at constant wind speed (ideally close to the wind speed required for the simulations) run on a detailed turbine model on a rigid tower and fixed foundation — normally run by the turbine designer. A proxy to the aerodynamic loads on the rotor and nacelle (RNA) is to take the horizontal yaw bearing loads. The process is then repeated for a range of nacelle yaw misalignments (for example every 15° for 360°). A look-up table with the horizontal yaw bearing load for the range of wind-rotor misalignments investigated is created. The simplified model of the aerodynamic loads on the RNA consists of a fixed blade (or wing) segment located at the hub, where aerodynamic drag and lift coefficients can be specified. Using the look-up tables created using the detailed turbine model, drag and lift coefficients are estimated as a function of the angle between the rotor and the wind direction.

This representation of the aerodynamic loading on the RNA was then verified against full-field turbulent wind simulations in fixed and floating conditions using a multi-megawatt commercial turbine. The results for the parameters concerning the floater, mooring and marine operations design were monitored (e.g. tower bottom loads, offsets, pitch, mooring tensions) for extreme conditions and the errors introduced by this simplified rotor are generally lower than 4%. This illustrates that this simplified representation of the turbine can be used by the various parties of the project during the early stages of the design, particularly when knowing the loading within the RNA and on higher sections of the tower is not important.
An Improved 2DCNN With Focal Loss Function for Blade Icing Detection of Wind Turbines Under Imbalanced SCADA Data
Authors: Peng Dandan , Liu Chenyu , Desmet Wim , Gryllias Konstantinos
Published: April 2021

The deployment of wind power plants in cold climate becomes ever more attractive due to the increased air density resulting from low temperatures, the high wind speeds, and the low population density. However, the cold climate conditions bring some additional challenges as itt can easily cause wind turbine blades to freeze. The frizzing ice on blades not only increases the energy required for the rotation of blades, resulting in a reduction in the power generation, but also increases the amplitude of the blades’ vibrations, which may cause the blade to break, affecting the power generation performance of the wind turbine and poses a threat to its safe operation.

Current published blade icing detection methods focus on studying the blade icing mechanism, building the model and then judging if it is iced or not. These models vary with different wind turbines and working conditions, so expertise knowledge is required. However, deep learning techniques may solve the abovementioned problem based on their excellent feature learning abilities but until now, there are only few studies on wind turbine blade icing detection based on the deep learning technology. Therefore, this paper proposes a novel blade icing detection model, named two-dimensional convolutional neural network with focal loss function (FL-2DCNN). The network takes the raw data collected by the Supervisory Control and Data Acquisition (SCADA) system as input, automatically learns the correlation between the different physical parameters in the dataset, and captures the abnormal information, in order to accurately output the detection results.

However, the amount of normal data collected by SCADA systems is usually much larger than the one of blade icing fault data, leading to a serious data imbalance problem. This problem makes it difficult for the network to obtain enough features related to the blade icing fault. Therefore the focal loss function is introduced to the FL-2DCNN to solve the aforementioned data imbalanced problem. The focal loss function can effectively balance the importance of normal samples and icing fault samples, so that the network can obtain more icing-related feature information from the icing fault samples, and thus the detection ability of the network can be improved. The experimental results of the proposed FL-2DCNN based on real SCADA data of wind turbines show that the proposed FL-2DCNN can effectively solve the sample imbalance problem and has significant potential in the blade icing detection task compared with other deep learning methods.
Functional Requirements for the WEIS Toolset to Enable Controls Co-Design of Floating Offshore Wind Turbines
Authors: Jonkman Jason , Wright Alan , Barter Garrett , Hall Matthew , Allison James , Herber Daniel R.
Published: April 2021

The goal of the new Wind Energy with Integrated Servo-control (WEIS) toolset under development is to provide the offshore wind industry and research communities with an open-source, user-friendly, flexible tool to enable true controls co-design (CCD) of the physical design of a floating offshore wind turbine together with the controller. WEIS will use a multifidelity library of models built on the foundations of WISDEM® and OpenFAST formerly known as FAST). This paper presents the WEIS development plan, including the functional requirements of WEIS (including improvements to WISDEM and OpenFAST) together with associated rationale for their establishment and a qualitative description of the modeling approaches that will be implemented to address these functional requirements. The development of WEIS is a project under the Aerodynamic Turbines Lighter and Afloat with Nautical Technologies and Integrated Servo-control program funded by the U.S. Department of Energy Advanced Research Projects Agency – Energy.
Modeling the Dynamics of Freely-Floating Offshore Wind Turbine Subjected to Waves With an Open-Source Overset Mesh Method
Authors: Pinguet Romain , Kanner Sam , Benoit Michel , Molin Bernard
Published: April 2021

The aim of this study is to develop a viscous numerical wave tank using a coupled solver between the wave generation and absorption toolbox waves2Foam, developed by Jacobsen et al. [1] and the overset method built in the open source CFD software OpenFOAM©. This wave tank can be used to analyze the behavior of Floating Offshore Wind Turbine (FOWT) in nonlinear waves. A mesh convergence analysis is presented on a simple 2D case in order to validate the CFD model. The results are compared to experimental data from the literature and show good agreement. The response of a floater developed for a FOWT is analyzed. The free surface elevation, heave and pitch motions are compared to experimental results from the literature. Comparisons between experimental data and numerical results are discussed.
Large-Scale Model Investigation for Monopile Decommissioning of Offshore Wind Turbines: Overpressure and Vibratory Pile
Authors: Hinzmann Nils , Lehn Patrick , Gattermann Jörg
Published: April 2021

As of now, only a small number of offshore foundations, related to offshore wind energy, were decommissioned in Europe. With a diameter up to nine meter, an embedment of about 40 meter and a set up effect over 25 years, the necessary force to pull the pile out of the seabed can be assumed, if at all determinable, to be enormous. The piles that were decommissioned were cut beneath the mud line, which leaves approximately one third of the foundation permanently in the seabed.

Different methods and techniques for a complete removal of offshore pile foundation are currently investigated within the project DeCoMP. Vibratory extraction aims for a reduction of the pile skin friction by creating a layer of less density between the pile shaft and pending soil.

During the design and planning process for vibratory installation or extraction a drivability prediction is a key element. In order to identify and characterize soil parameter for the numerical simulation of a drivability prediction, large-scale tests are performed by the Institute of Geomechanics and Geotechnics of the Technische Universität Braunschweig (IGG-TUBS) [1].

In this paper first results of pilot tests with two vibrators are presented and key elements such as crane uplift, frequency and acceleration displayed.
NOAA-CFSR Offshore Wind Validation
Authors: Pizzigalli Claudia , Giovanetti Giancarlo , Pedinelli Lisa , Padilla-Hernandez Roberto
Published: April 2021

The wind field at sea is of considerable interest to identify suitable sites and for designing offshore wind energy production facility. However, the reliability of wind information suffers from the relative scarcity of offshore wind measurements to validate the wind models used in assessments. This paper presents a comparison of the publicly available NOAA-CFSR global re-analysis data set against offshore wind measurement collected in West Africa, Mediterranean Sea, Barents Sea and NW Australia, with the goal to investigate — in widely different meteorological conditions — the overall model reliability, in term of statistical indices of performance: Moreover, an attempt has been made to ascertain the representative averaging duration of model wind and the reliability of engineering formulas used to correlate wind of different averaging durations.
A Comparison of Time Domain Seismic Analysis Methods for Offshore Wind Turbine Structures: Superelement Approach Versus Integrated Approach
Authors: Collier William , Alblas Laurens , Wu Jiang Hai
Published: April 2021

Offshore wind structures are being designed for seismically active areas. Load calculations can be performed in an integrated way or using a superelement approach. This study aims to demonstrate that these two approaches can give equivalent results when earthquake excitations are included as an applied load in the superelement approach.

Models of a generic 7MW wind turbine on a jacket support structure are defined in aeroelastic code Bladed and strength assessment software Sesam. Analysis is performed on the stand-alone jacket and support structure, and also including the rotor nacelle assembly. Load conditions of earthquakes, waves and wind are considered.

Time domain results show that the superelement and integrated methods for modelling earthquake loading are equivalent in terms of the motions and loads at key points of the support structure. When the tower and RNA are included, an excellent match is seen for all studied variables: interface and tower top motions, loads at the interface and in the jacket, and displacements of jacket nodes.

Analysis of the stand-alone jacket highlights differences in the approaches with regard to coupling of the hydrodynamic loading to the earthquake motion, which is absent in the superelement method. However, this does not appear to be significant for realistic cases including the tower and RNA.
Potential Geo-Hazards to Floating Offshore Wind Farms in the US Pacific
Authors: Tajalli Bakhsh Tayebeh , Simpson Kent , LaPierre Tony , Monim Mahmud , Dahl Jason , Spaulding Malcolm , Rowe Jill , Miller Jennifer , O’Connell Daniel
Published: April 2021

To help the selection of suitable sites for development of offshore wind projects in the US on the coasts of California, Oregon and Hawaii, the Bureau of Ocean Energy Management (BOEM) funded this study to assess the potential geo-hazards in this region. First, a comprehensive review of potential threats to the sites based on historic events is provided. The geospatial indexing for the call areas are then calculated based on weights associated with inputs, consisting of: sea floor slope, soil type, and seismicity (peak ground acceleration data of 500 year event). Finally, suitability indices are provided for each region.

To perform a suitability analysis using geospatial indexing, all input factors are first standardized into a common scale, then a weighted overlay function is applied. Each of the criteria in the analysis is multiplied by the weights defined based on their importance in the region and then added together and suitability maps for each lease block are developed. Comprehensive maps of geohazards and geological data, suitability index maps and suitability rankings for the area of interest are being generated and presented online. This paper focuses on the floating windfarm call areas offshore California, including Humboldt, Morro Bay and Diablo Canyon, and presents the new approach for evaluating, integrating and indexing geospatial geohazard data for offshore windfarms, and the state-of-the-art suitability analysis approach. This new method can be also beneficial in the other parts of the world (e.g. East Asia), and similar concept can be implemented to evaluate the suitability of sites, based on the hazards in the area of interest.
Performance Analysis of Tacholess Rotation Speed Estimation Methods for Condition Monitoring of Gearboxes of Offshore Wind Farm
Authors: Peeters Cédric , Antoni Jérôme , Leclère Quentin , Helsen Jan
Published: April 2021

This paper investigates the efficacy and reliability of three different state-of-the-art rotation speed estimation techniques on a very large set of experimental vibration data originating from thirty offshore wind turbine gearboxes. The three methods include the multi-order probabilistic approach, the phase demodulation method based on the frequency-domain energy operator, and the multi-harmonic demodulation technique. The goal is twofold: to assess statistically the performance of present-day vibration-based rotation speed estimation techniques on challenging experimental data, and to establish indirect rotation speed estimation through vibration data as a viable alternate solution to the conventional solution involving a direct measurement with a physical device such as a tachometer or an angle encoder. The results show that while all three techniques attain satisfying results, the multi-harmonic demodulation technique produces the most accurate speed estimate for the majority of all measurements whilst also being flexible in its usage.
Micro–X-ray fluorescence (µXRF) analysis of proximal impactites: High-resolution element mapping, digital image analysis, and quantifications
Authors: Kaskes* Pim , Déhais* Thomas , de Graaff Sietze J. , Goderis Steven , Claeys Philippe
Published: April 2021

Quantitative insights into the geochemistry and petrology of proximal impactites are fundamental to understand the complex processes that affected target lithologies during and after hypervelocity impact events. Traditional analytical techniques used to obtain major- and trace-element data sets focus predominantly on either destructive whole-rock analysis or laboratory-intensive phase-specific micro-analysis. Here, we present micro–X-ray fluorescence (µXRF) as a state-of-the-art, time-efficient, and nondestructive alternative for major- and trace-element analysis for both small and large samples (up to 20 cm wide) of proximal impactites. We applied µXRF element mapping on 44 samples from the Chicxulub, Popigai, and Ries impact structures, including impact breccias, impact melt rocks, and shocked target lithologies. The µXRF mapping required limited to no sample preparation and rapidly generated high-resolution major- and trace-element maps (~1 h for 8 cm2, with a spatial resolution of 25 µm). These chemical distribution maps can be used as qualitative multi-element maps, as semiquantitative single-element heat maps, and as a basis for a novel image analysis workflow quantifying the modal abundance, size, shape, and degree of sorting of segmented components. The standardless fundamental parameters method was used to quantify the µXRF maps, and the results were compared with bulk powder techniques. Concentrations of most major elements (Na2O–CaO) were found to be accurate within 10% for thick sections. Overall, we demonstrate that µXRF is more than only a screening tool for heterogeneous impactites, because it rapidly produces bulk and phase-specific geochemical data sets that are suitable for various applications within the earth sciences.
The carbonate compensation depth in the South Atlantic Ocean since the Late Cretaceous
Authors: Dutkiewicz Adriana , Müller R. Dietmar
Published: April 2021

Deep-sea carbonate deposition is a complex process that is encapsulated in the carbonate compensation depth (CCD)—a facies boundary separating calcareous sediments from non-carbonates. Knowing how the CCD has varied over time is important for understanding and predicting the distribution of seafloor sediments and assessing their role in the global carbon cycle. We focus on the South Atlantic Ocean where the most recent CCD curve is based on Deep Sea Drilling Project (DSDP) Leg 73 sites drilled in 1980 in the South Atlantic Ocean. We compute the South and central South Atlantic CCD from the Late Cretaceous to the present day using updated age models from 45 DSDP and Ocean Drilling Program sites and backtracking with lithology-specific decompaction, eustasy, and dynamic topography. Our models extend further back in time and show more fluctuations than previous reconstructions, with the CCD varying by hundreds of meters during a span of 2–3 m.y. The addition of eustasy and dynamic topography deepens the CCD by as much as 500 m between 74 Ma and 45 Ma, and by ∼200 m during the Cenozoic. The central South Atlantic CCD diverges from the average South Atlantic CCD during the Eocene and Miocene, when it was ∼1 km shallower. These regional deviations may be due to changes in primary productivity and/or carbonate dissolution leading to reduced carbonate accumulation rates. Our CCD curves highlight the importance of regional processes in carbonate deposition across the South Atlantic and provide improved constraints for the modeling of geochemical cycles.
Deep Learning--based Text Classification
Authors: Minaee Shervin , Kalchbrenner Nal , Cambria Erik , Nikzad Narjes , Chenaghlu Meysam , Gao Jianfeng
Published: April 2021

Deep learning--based models have surpassed classical machine learning--based approaches in various text classification tasks, including sentiment analysis, news categorization, question answering, and natural language inference. In this article, we provide a comprehensive review of more than 150 deep learning--based models for text classification developed in recent years, and we discuss their technical contributions, similarities, and strengths. We also provide a summary of more than 40 popular datasets widely used for text classification. Finally, we provide a quantitative analysis of the performance of different deep learning models on popular benchmarks, and we discuss future research directions.
Towards Dynamic Checklists
Authors: Kulp Leah , Sarcevic Aleksandra , Cheng Megan , Burd Randall S.
Published: April 2021

The goal of this in-the-wild study was to understand how different patient, provider, and environment contexts affected the use of a tablet-based checklist in a dynamic medical setting. Fifteen team leaders used the digital checklist in 187 actual trauma resuscitations. The measures of checklist interactions included the number of unchecked items and the number of notes written on the checklist. Of the 10 contexts we studied, team leaders’ arrival after the patient and patients with penetrating injuries were both associated with more unchecked items. We also found that the care of patients with external injuries contributed to more notes written on the checklist. Finally, our results showed that more experienced leaders took significantly more notes overall and more numerical notes than less experienced leaders. We conclude by discussing design implications and steps that can be achieved with context-aware computing towards adaptive checklists that meet the needs of dynamic use contexts.
Establishing Context
Authors: Norrie Christopher S. , Waller Annalu , Hannah Elizabeth F. S.
Published: April 2021

Current mechanisms for adopting and supporting high-tech augmentative and alternative communication (AAC) within special-education appear limited in their success, despite recognition of the potential benefits they represent for young emerging communicators. Prior research in this field has been restricted to discrete survey or interview methodologies. We present a five-month mixed-methods ethnographic study in a special-education school to explore the facilitators and barriers experienced by those using technology, with children who have little or no functional speech, to stimulate communication and language comprehension. Our analysis supports the outcomes of earlier studies, but also furnishes novel insights into the scale and urgency of addressing the problem—with implications for user-centred design within this community. We highlight infrastructure, policy, and recruitment deficits, and propose a two-fold solution: (i) an increase in engagement with this population through the provision of enhanced, user-centred support; and (ii) induction of the cross-disciplinary role of Assistive Technologist, to serve as mediator between teacher, aided communicator, and their assistive technology. This work represents a contribution towards establishing more effective operational, interactional, and pedagogical support for learners using high-tech communication devices.
Visual Affordance and Function Understanding
Authors: Hassanin Mohammed , Khan Salman , Tahtali Murat
Published: April 2021

Nowadays, robots are dominating the manufacturing, entertainment, and healthcare industries. Robot vision aims to equip robots with the capabilities to discover information, understand it, and interact with the environment, which require an agent to effectively understand object affordances and functions in complex visual domains. In this literature survey, first, “visual affordances” are focused on and current state-of-the-art approaches for solving relevant problems as well as open problems and research gaps are summarized. Then, sub-problems, such as affordance detection, categorization, segmentation, and high-level affordance reasoning, are specifically discussed. Furthermore, functional scene understanding and its prevalent descriptors used in the literature are covered. This survey also provides the necessary background to the problem, sheds light on its significance, and highlights the existing challenges for affordance and functionality learning.
Cytology Image Analysis Techniques Toward Automation
Authors: Mitra Shyamali , Das Nibaran , Dey Soumyajyoti , Chakraborty Sukanta , Nasipuri Mita , Naskar Mrinal Kanti
Published: April 2021

Cytology is a branch of pathology that deals with the microscopic examination of cells for diagnosis of carcinoma or inflammatory conditions. In the present work, the term cytology is used to indicate solid organ cytology. Automation in cytology started in the early 1950s with an aim to reduce manual efforts in the diagnosis of cancer. The influx of intelligent systems with high computational power and improved specimen collection techniques helped to achieve technological heights in the cytology automation process. In the present survey, we focus on image analysis techniques paving the way to automation in cytology. We take a short tour of 17 types of solid organ cytology to explore various segmentation and/or classification techniques that evolved during the past three decades to automate cytology image analysis. It is observed that most of the works are aligned toward three types of cytology: Cervical, Breast, and Respiratory tract cytology. These are discussed elaborately in the article. Commercial systems developed during the period are also summarized to comprehend the overall growth in respective domains. Finally, we discuss different state-of-the-art methods and related challenges to provide prolific and competent future research directions in bringing cytology-based commercial systems into the mainstream.
Social Theory and Legal Theory: Contemporary Interactions
Authors: Cotterrell Roger
Published: April 2021

This article identifies points of comparison between legal theory and social theory and possibilities for research communication between them. The current range of both fields is such that each must be seen as a compendium of very diverse intellectual projects. So, the article explores particular contemporary themes around which the interests of juristic scholars and social theorists are converging, albeit that their theoretical aims often differ. Contrasting and complementary juristic and social theoretical perspectives are considered in relation to the following: the future of legal individualism, the identity of law as a social phenomenon, the relations of law and power, the contribution of law to societal integration, and the changing relation of law and the state. The article argues that these five themes reveal major intellectual challenges for both legal theory and social theory and productive future areas for inquiry.
Law and/or/as Civility
Authors: Bybee Keith J.
Published: April 2021

The United States, like many countries around the world today, is experiencing the disruption of traditional patterns of governance and the breaking of norms of everyday behavior. If we identify the norms of governance with the rule of law, and if we consider the norms of everyday behavior to constitute civility, then we can approach the current state of affairs by asking how law and civility relate to one another. I survey and discuss three different understandings of the law/civility relationship: law and civility, law or civility, and law as civility. Each of these understandings is an analytical resource, and as such, each understanding captures a facet of a complex relationship and provides a way to think about our current age of unrest.
The Cortical Motor Areas and the Emergence of Motor Skills: A Neuroanatomical Perspective
Authors: Strick Peter L. , Dum Richard P. , Rathelot Jean-Alban
Published: April 2021

What changes in neural architecture account for the emergence and expansion of dexterity in primates? Dexterity, or skill in performing motor tasks, depends on the ability to generate highly fractionated patterns of muscle activity. It also involves the spatiotemporal coordination of activity in proximal and distal muscles across multiple joints. Many motor skills require the generation of complex movement sequences that are only acquired and refined through extensive practice. Improvements in dexterity have enabled primates to manufacture and use tools and humans to engage in skilled motor behaviors such as typing, dance, musical performance, and sports. Our analysis leads to the following synthesis: The neural substrate that endows primates with their enhanced motor capabilities is due, in part, to ( a) major organizational changes in the primary motor cortex and ( b) the proliferation of output pathways from other areas of the cerebral cortex, especially from the motor areas on the medial wall of the hemisphere.
Comparison of IORT (Radical and Boost Dose) and EBRT in Terms of Disease-Free Survival and Overall Survival according to Demographic, Pathologic, and Biological Factors in Patients with Breast Cancer
Authors: Hashemi Solmaz , Javadi Seyedmohammadreza , Akbari Mohammad Esmaeil , Mirzaei Hamidreza , Mahdavi Seied Rabi
Published: April 2021

Background. The standard treatment for breast cancer is breast-conserving surgery (BCS) with radiotherapy. If external beam radiation therapy (EBRT) can be safely replaced with intraoperative radiotherapy (IORT), it will help patients to save their breast and to have equivocal or better results in DFS and overall survival (OS). Methods. A total of 2022 patients with breast cancer treated during 6 years were enrolled in the current study. A total of 657, 376, and 989 patients received EBRT, radical, and boost dose by IORT, respectively, according to the IRIORT consensus protocol. The primary endpoint was recurrence and death. The secondary endpoint was the role of variables in recurrence and death. Results. With a mean follow-up of 34.5 and 40.18 months for the IORT and EBRT groups, respectively, there was a significant difference in DFS between electron boost and X-ray boost groups (

P
=
0.037

) and the electron radical group compared with EBRT (

P
=
0.025

), but there was no significant difference between other boost and radical groups in DFS and OS. Conclusions. IORT can be a preferred treatment modality because of its noninferior outcomes, and in some special conditions, it has superior outcomes compared to EBRT, particularly in delivering radical dose with IORT.