scholarly journals A Concise and Geometrically Exact Planar Beam Model for Arbitrarily Large Elastic Deformation Dynamics

2021 ◽  
Vol 7 ◽  
Author(s):  
Gerold Huber ◽  
Dirk Wollherr ◽  
Martin Buss
Keyword(s):  
Research Field ◽  
Full Potential ◽  
Beam Model ◽  
Control Applications ◽  
Control Structures ◽  
Small Deflection ◽  
Planar Shear ◽  
Deformation Dynamics ◽  
Free Case ◽  
Large Elastic Deformation

The potential of large elastic deformations in control applications, e.g., robotic manipulation, is not yet fully exploited, especially in dynamic contexts. Mainly because essential geometrically exact continuum models are necessary to express these arbitrarily large deformation dynamics, they typically result in a set of nonlinear, coupled, partial differential equations that are unsuited for control applications. Due to this lack of appropriate models, current approaches that try to exploit elastic properties are limited to either small deflection assumptions or quasistatic considerations only. To promote further exploration of this exciting research field of large elastic deflection control, we propose a geometrically exact, but yet concise a beam model for a planar, shear-, and torsion-free case without elongation. The model is derived by reducing the general geometrically exact the 3D Simo–Reissner beam model to this special case, where the assumption of inextensibility allows expressing the couple of planar Cartesian parameters in terms of the curve tangent angle of the beam center line alone. We further elaborate on how the necessary coupling between position-related boundary conditions (i.e., clamped and hinged ends) and the tangent angle parametrization of the beam model can be incorporated in a finite element method formulation and verify all derived expressions by comparison to analytic initial value solutions and an energy analysis of a dynamic simulation result. The presented beam model opens the possibility of designing online feedback control structures for accessing the full potential that elasticity in planar beam dynamics has to offer.

scholarly journals A Systematic Literature Review of the Factors of Influence on the Environmental Impact of ICT

Technologies ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 85 ◽  
Author(s):  
Albert Hankel ◽  
Gaston Heimeriks ◽  
Patricia Lago
Keyword(s):  
Environmental Impact ◽  
Literature Review ◽  
Conceptual Framework ◽  
Systematic Literature Review ◽  
Research Field ◽  
Full Potential ◽  
Starting Point ◽  
Information And Communication ◽  
Factors Of Influence ◽  
Green Ict

Context: Many publications have described, measured, tracked or assessed Information and Communication Technology (ICT) activities that impact the environment. A complete conceptual view of the environmental impact of ICT can be described in three orders of effect: Direct, indirect and systemic. Objective: The goal of this study is to find out how the existing literature contributes towards our understanding of the environmental impact of ICT. We approach this question by identifying factors that can be of influence on the environmental impact and map these factors onto a conceptual framework of Green ICT. Method: We used a systematic literature review to collect factors of influence regarding the environmental impact of ICT. Results: From the data we collected and the analyses made, we created a taxonomy, and report on the frequencies of the factors of influence in the primary studies as well as gaps and additions compared to the conceptual framework. We found five main classes of influence that can form a continuous cycle, but noted that the research field is strongly focused on the direct impact of ICT. Conclusion: Our study contributes towards a better understanding of the environmental impact of ICT by framing factors of influence in a conceptual framework. The taxonomy we create and the analysis of the studies could be helpful in defining a research agenda, to further enable the full potential of Green ICT. In addition, the taxonomy can be used as a starting point for a practical tool, for organizations that wish to apply Green ICT to its full extent.

scholarly journals Special Issue on Automatic Application Tuning for HPC Architectures

2014 ◽  
Vol 22 (4) ◽  
pp. 259-260 ◽  
Author(s):  
Siegfried Benkner ◽  
Franz Franchetti ◽  
Hans Michael Gerndt ◽  
Jeffrey K. Hollingsworth
Keyword(s):  
High Performance ◽  
Research Field ◽  
Performance Tuning ◽  
Full Potential ◽  
Research Groups ◽  
Special Issue ◽  
The World ◽  
And Performance ◽  
Application Tuning ◽  
Performance Computing

High Performance Computing architectures have become incredibly complex and exploiting their full potential is becoming more and more challenging. As a consequence, automatic performance tuning (autotuning) of HPC applications is of growing interest and many research groups around the world are currently involved. Autotuning is still a rapidly evolving research field with many different approaches being taken. This special issue features selected papers presented at the Dagstuhl seminar on “Automatic Application Tuning for HPC Architectures” in October 2013, which brought together researchers from the areas of autotuning and performance analysis in order to exchange ideas and steer future collaborations.

scholarly journals Equivalent circuit models of two-layer flexure beams with excitation by temperature, humidity, pressure, piezoelectric or piezomagnetic interactions

2014 ◽  
Vol 3 (2) ◽  
pp. 187-211 ◽  
Author(s):  
U. Marschner ◽  
G. Gerlach ◽  
E. Starke ◽  
A. Lenk
Keyword(s):  
Network Theory ◽  
Natural Frequencies ◽  
General System ◽  
Beam Model ◽  
System Behavior ◽  
Linear Network ◽  
Basic Principles ◽  
Small Deflection ◽  
Circuit Representation ◽  
Lumped Elements

Abstract. Two-layer flexure beams often serve as basic transducers in actuators and sensors. In this paper a generalized description of their stimuli-influenced mechanical behavior is derived. For small deflection angles this description includes a multi-port circuit or network representation with lumped elements for a beam part of finite length. A number of coupled finite beam parts model the dynamic behavior including the first natural frequencies of the beam. For piezoelectric and piezomagnetic interactions, reversible transducer models are developed. The piezomagnetic two-layer beam model is extended to include solenoid and planar coils. Linear network theory is applied in order to determine network parameters and to simplify the circuit representation. The resulting circuit model is the basis for a fast simulation of the dynamic system behavior with advanced circuit simulators and, thus, the optimization of the system. It is also a useful tool for understanding and explaining this multi-domain system through basic principles of general system theory.

scholarly journals On Nonlinear Dynamics of Planar Shear Indeformable Beams

1986 ◽  
Vol 53 (3) ◽  
pp. 619-624 ◽  
Author(s):  
A. Luongo ◽  
G. Rega ◽  
F. Vestroni
Keyword(s):  
Displacement Component ◽  
Forced Oscillations ◽  
Beam Model ◽  
Constraint Condition ◽  
Unified Approach ◽  
Response Curves ◽  
Nonlinear Beam ◽  
Planar Shear ◽  
The Stability ◽  
Steady State Solutions

The planar forced oscillations of shear indeformabie beams with either movable or immovable supports are studied through a unified approach. An exact nonlinear beam model is referred to and a consistent procedure up to order three nonlinearities is followed. By eliminating the longitudinal displacement component through a constraint condition and assuming one mode, the problem is reduced to one nonlinear differential equation. A perturbational solution in the neighborhood of the resonant frequency is determined and the stability of the steady-state solutions is studied. The dependence of the phenomenon on the geometrical and mechanical characteristics of the system is put into light and the frequency-response curves for different boundary conditions are furnished.

scholarly journals Documentation and Cultural Heritage Inventories - Case of the Historic City of Ahmadabad

2015 ◽  
Vol II-5/W3 ◽  
pp. 271-278 ◽  
Author(s):  
K. Shah
Keyword(s):  
Time Frame ◽  
Research Field ◽  
Management Tool ◽  
Full Potential ◽  
Monumental Architecture ◽  
Digital Database ◽  
Indian State ◽  
City Structure ◽  
Development And Management ◽  
Historic City

Located in the western Indian state of Gujarat, the historic city of Ahmadabad is renowned for the unparalleled richness of its monumental architecture, traditional house form, community based settlement patterns, city structure, crafts and mercantile culture. This paper describes the process followed for documentation and development of comprehensive Heritage Inventories for the historic city with an aim of illustrating the Outstanding Universal Values of its Architectural and Urban Heritage. The exercise undertaken between 2011 & 2014 as part of the preparation of world heritage nomination dossier included thorough archival research, field surveys, mapping and preparation of inventories using a combination of traditional data procurement and presentation tools as well as creation of advanced digital database using GIS. The major challenges encountered were: need to adapt documentation methodology and survey formats to field conditions, changing and ever widening scope of work, corresponding changes in time frame, management of large quantities of data generated during the process along with difficulties in correlating existing databases procured from the local authority in varying formats. While the end result satisfied the primary aim, the full potential of Heritage Inventory as a protection and management tool will only be realised after its acceptance as the statutory list and its integration within the larger urban development plan to guide conservation, development and management strategy for the city. The rather detailed description of evolution of documentation process and the complexities involved is presented to understand the relevance of methods used in Ahmadabad and guide similar future efforts in the field.

scholarly journals Combined Use of EMG and EEG Techniques for Neuromotor Assessment in Rehabilitative Applications: A Systematic Review

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7014
Author(s):  
Cristina Brambilla ◽  
Ileana Pirovano ◽  
Robert Mihai Mira ◽  
Giovanna Rizzo ◽  
Alessandro Scano ◽  
...  
Keyword(s):  
Systematic Review ◽  
Research Field ◽  
Lower Limbs ◽  
Full Potential ◽  
Process Data ◽  
Pilot Studies ◽  
Scientific Databases ◽  
Research Fields ◽  
Emg Signal ◽  
Standard Procedures

Electroencephalography (EEG) and electromyography (EMG) are widespread and well-known quantitative techniques used for gathering biological signals at cortical and muscular levels, respectively. Indeed, they provide relevant insights for increasing knowledge in different domains, such as physical and cognitive, and research fields, including neuromotor rehabilitation. So far, EEG and EMG techniques have been independently exploited to guide or assess the outcome of the rehabilitation, preferring one technique over the other according to the aim of the investigation. More recently, the combination of EEG and EMG started to be considered as a potential breakthrough approach to improve rehabilitation effectiveness. However, since it is a relatively recent research field, we observed that no comprehensive reviews available nor standard procedures and setups for simultaneous acquisitions and processing have been identified. Consequently, this paper presents a systematic review of EEG and EMG applications specifically aimed at evaluating and assessing neuromotor performance, focusing on cortico-muscular interactions in the rehabilitation field. A total of 213 articles were identified from scientific databases, and, following rigorous scrutiny, 55 were analyzed in detail in this review. Most of the applications are focused on the study of stroke patients, and the rehabilitation target is usually on the upper or lower limbs. Regarding the methodological approaches used to acquire and process data, our results show that a simultaneous EEG and EMG acquisition is quite common in the field, but it is mostly performed with EMG as a support technique for more specific EEG approaches. Non-specific processing methods such as EEG-EMG coherence are used to provide combined EEG/EMG signal analysis, but rarely both signals are analyzed using state-of-the-art techniques that are gold-standard in each of the two domains. Future directions may be oriented toward multi-domain approaches able to exploit the full potential of combined EEG and EMG, for example targeting a wider range of pathologies and implementing more structured clinical trials to confirm the results of the current pilot studies.

Aerothermoelastic Behavior of Supersonic Rotating Thin-Walled Beams Made of Functionally Graded Materials

2006 ◽  
Author(s):  
S. Ahmad Fazelzadeh ◽  
Mohammad Hosseini
Keyword(s):  
Wall Temperature ◽  
Equations Of Motion ◽  
Functionally Graded ◽  
Beam Model ◽  
Graded Materials ◽  
Aerodynamic Pressure ◽  
Small Deflection ◽  
Flow Motion ◽  
Graded Material ◽  
Thin Walled

In this study a thin walled-beam made of functionally graded material (FGM) which is used as rotating turbomachinery blade under the aerothermoelastic loading is considered. The governing equations, based on small deflection with transverse shear and rotary inertias beam model, are considered with the presetting angle included. The effects of constant angular velocity and wall temperature due to flow motion also have been included. Quasi-steady aerodynamic pressure loadings are determined using first order piston theory as well as steady wall temperature through gas dynamic theory. Due to aerothermoelastic terms in loading, the gyroscopic matrix was generated in equations of motion. The blade partial differential equations are transformed into a set of ordinary differential equation through the Galerkin approach. The resulting system of equations is solved through the numerical integration. The effects of the variation of Mach number and geometric parameters on the natural frequencies are simulated. Results are indicative of the important influence of aerothermoelastic parameters on vibration behavior.

Homogenized Energy Model and Markov Chain Monte Carlo Simulations for Macro Fiber Composites Operating in Broadband Regimes

2012 ◽  
Author(s):  
Zhengzheng Hu ◽  
Ralph C. Smith ◽  
Nathanial Burch ◽  
Michael Hays ◽  
William S. Oates
Keyword(s):  
Monte Carlo ◽  
Markov Chain ◽  
Markov Chain Monte Carlo ◽  
Monte Carlo Simulations ◽  
Fiber Composites ◽  
Production Costs ◽  
Full Potential ◽  
Beam Model ◽  
Posterior Probability Distribution ◽  
Homogenized Energy Model

Macro Fiber Composites (MFCs), comprised of PZT fibers, are being considered for a variety of applications due to their flexibility and relatively low production costs. Like other PZT actuators, MFCs also exhibit hysteresis and constitutive nonlinearities that must be characterized in models and control designs to achieve the full potential. Here we use an Euler-Bernoulli beam model coupled with the homogenized energy strain model to predict the structural/hysteretic response of a thin cantilever beam with an MFC patch attached during a series of frequency sweep experiments. Optimization routines are employed to optimized both MFC parameters and beam parameters using a subset of displacement data. The posterior probability distribution of each model parameter is estimated using Markov Chain Monte Carlo simulations. Finally, we present model predictions with quantified uncertainties.

Significance and implementation of SMART Monitoring Tools

2020 ◽  
Author(s):  
Uta Koedel ◽  
Peter Dietrich ◽  
Erik Nixdorf ◽  
Philipp Fischer
Keyword(s):  
Real Time ◽  
Sensor Network ◽  
Monitoring Network ◽  
Research Field ◽  
Data Availability ◽  
Sensor Data ◽  
Integrated Analysis ◽  
Full Potential ◽  
Automatic Data ◽  
The Status

<p>The term “SMART Monitoring” is often used in digital projects to survey and analyze data flows in near- or realtime. The term is also adopted in the project Digital Earth (DE) which was jointly launched in 2018 by the eight Helmholtz centers of the research field Earth and Environment (E&E) within the framework of the German Ministry of Education and Research (BMBF). Within DE, the “SMART monitoring” sub-project aims at developing workflows and processes to make scientific parameters and the related datasets SMART, which means <strong>s</strong>pecific, <strong>m</strong>easurable, <strong>a</strong>ccepted, <strong>r</strong>elevant, and <strong>t</strong>rackable (SMART).</p><p>“SMART Monitoring” in DE comprises a combination of hard- and software tools to enhance the traditional sequential monitoring approach - where data are step-by-step analyzed and processed from the sensor towards a repository - into an integrated analysis approach where information on the measured value together with the status of each sensor and possible auxiliary relevant sensor data in a sensor network are available and used in real-time to enhance the sensor output concerning data accuracy,  precision, and data availability. Thus, SMART Monitoring could be defined as a computer-enhanced monitoring network with automatic data flow control from individual sensors in a sensor network to databases enhanced by automated (machine learning) and near real-time interactive data analyses/exploration using the full potential of all available sensors within the network. Besides, “SMART monitoring” aims to help for a better adjustment of sensor settings and monitoring strategies in time and space in iterative feedback.</p><p>This poster presentation will show general concepts, workflows, and possible visualization tools based on examples that support the SMART Monitoring idea.</p>

Envisioning Mobile Learning as the Future of Teaching and Learning via Technology

2014 ◽  
pp. 324-341 ◽  
Author(s):  
Umera Imtinan ◽  
Vanessa Chang ◽  
Tomayess Issa
Keyword(s):  
Information And Communication Technologies ◽  
Mobile Learning ◽  
Teaching And Learning ◽  
Research Field ◽  
Mobile Technologies ◽  
Learning Theories ◽  
Learning Needs ◽  
Full Potential ◽  
The World ◽  
The Future

Technology has played a key role in reshaping the way education is being delivered in university environments. Mobile technologies are one of the latest technologies to enter the higher education arenas around the world, offering great potential for teaching and learning. Students and teachers have been using mobile devices for formal and informal collaboration, communication, and connectivity within learning environments for a couple of decades without recognizing it as mobile learning. Mobile learning needs to be researched and theorized in order to be included in formal educational Information and Communication Technologies and its full potential harnessed for the future generations. A number of mobile learning researchers borrowed traditional learning models as theoretical foundations for mobile learning research. However, theories from a diverse range of subject areas such as Education, Information Systems, Human-Computer Interaction, and Telecommunication Engineering have also been used as the basis for mobile learning projects around the world. This incorporation of a diversity of disciplines and subjects has made mobile learning a multidisciplinary research field. This chapter aims to review the current mobile learning theories, models, and frameworks with the lens of mobile learning characteristics and challenges pointed out by prominent mobile learning researchers across the world in order to present the case of mobile learning as the future of teaching and learning.

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