Evolutionary Optimization of Passive Compensators to Improve Earthquake Resistance

2013 ◽  
pp. 250-273
Author(s):  
Rolf Steinbuch
Keyword(s):  
Earthquake Engineering ◽  
Optimization Strategy ◽  
Local Optima ◽  
Good Design ◽  
To Come ◽  
Mass Spring ◽  
Stiffness And Damping ◽  
The Impact ◽  
Parent Generation ◽  
Multidimensional Optimization

Compensators are widely used to influence the dynamic response of excited structures. The coupling of additional masses with defined stiffness and damping to the vibrating elements reduces or avoids unwanted oscillations. In earthquake engineering, compensators often consist of one or a small number of such additional mass-spring combinations. To come up with a good design of the compensators, a multidimensional optimization problem has to be solved. As there might be many local optima, evolutionary approaches are the appropriate choice of the optimization strategy. They start with some basic designs. Then a sequence of generations of design variants is studied. The members of each generation are derived from the parent generation by crossing and mutation. The best kids are the parents of the next generation. Optimization results show that the use of compensating systems may essentially reduce the impact of an earthquake.

Hybrid optimization strategy beyond local optima in aerospace panel designs

AIAA Journal ◽  
1999 ◽  
Vol 37 ◽  
pp. 588-593
Author(s):  
K. L. Chan ◽  
David Kennedy ◽  
Fred W. Williams
Keyword(s):  
Hybrid Optimization ◽  
Optimization Strategy ◽  
Local Optima

Fluxus and the Absurd (1961–62)

2017 ◽  
Author(s):  
Benjamin R. Levy
Keyword(s):  
Second Life ◽  
The Self ◽  
Major Work ◽  
The Future ◽  
To Come ◽  
The Impact

After John Cage’s 1958 Darmstadt lectures, many European composers developed an interest in absurdity and artistic provocation. Although Ligeti’s fascination with Cage and his association with the Fluxus group was brief, the impact it had on his composition was palpable and lasting. A set of conceptual works, The Future of Music, Trois Bagatelles, and Poème symphonique for one hundred metronomes, fall clearly into the Fluxus model, even as the last has taken on a second life as a serious work. This spirit, however, can also be seen in the self-satire of Fragment and the drama and irony of Volumina, Aventures, and Nouvelles Aventures. The sketches for Aventures not only show the composer channeling this humor into a major work but also prove to be a fascinating repository of ideas that Ligeti would reuse in the years to come.

scholarly journals Vibro-Acoustical Sensitivities of Stiffened Aircraft Structures Due to Attached Mass-Spring-Dampers with Uncertain Parameters

Aerospace ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 174
Author(s):  
Johannes Seidel ◽  
Stephan Lippert ◽  
Otto von Estorff
Keyword(s):  
System Response ◽  
Fuzzy Arithmetic ◽  
Parameter Uncertainties ◽  
Excitation Spectra ◽  
Radiated Noise ◽  
Linking Elements ◽  
Manufacturing Tolerances ◽  
Suitable Framework ◽  
Mass Spring ◽  
The Impact

The slightest manufacturing tolerances and variances of material properties can indeed have a significant impact on structural modes. An unintentional shift of eigenfrequencies towards dominant excitation frequencies may lead to increased vibration amplitudes of the structure resulting in radiated noise, e.g., reducing passenger comfort inside an aircraft’s cabin. This paper focuses on so-called non-structural masses of an aircraft, also known as the secondary structure that are attached to the primary structure via clips, brackets, and shock mounts and constitute a significant part of the overall mass of an aircraft’s structure. Using the example of a simplified fuselage panel, the vibro-acoustical consequences of parameter uncertainties in linking elements are studied. Here, the fuzzy arithmetic provides a suitable framework to describe uncertainties, create combination matrices, and evaluate the simulation results regarding target quantities and the impact of each parameter on the overall system response. To assess the vibrations of the fuzzy structure and by taking into account the excitation spectra of engine noise, modal and frequency response analyses are conducted.

scholarly journals Financing Growth through Remittances and Foreign Direct Investment: Evidences from Balkan Countries

2021 ◽  
Vol 14 (3) ◽  
pp. 117
Author(s):  
Esmeralda Jushi ◽  
Eglantina Hysa ◽  
Arjona Cela ◽  
Mirela Panait ◽  
Marian Catalin Voica
Keyword(s):  
Developing Economies ◽  
Central Banks ◽  
Sustainable Growth ◽  
Time Interval ◽  
Foreign Direct Investments ◽  
Factors Affecting ◽  
Balkan Countries ◽  
To Come ◽  
Sustainable Economic Growth ◽  
The Impact

The ultimate goal of central banks, worldwide, is to promote the foundations for sustainable economic growth. In the case of developing economies, in particular, such objective requires time, huge efforts, attention, and plenty of resources in order to be accomplished to the fullest degree. This paper thoroughly investigates key factors affecting Balkan countries’ economic development (as measured by gross domestic product (GDP) growth), focusing especially on the impact of remittances. The analysis was done over an 18-year time interval (2000–2017) and builds on 144 observations. The data figures were retrieved from the World Bank database while two dummies were created to test the impact of the last financial crisis (2008–2012). Econometric tools were employed to carry out a broad analysis on the interdependencies that exist and, in particular, to determine the role of remittance income on growth. The vector auto regressive model was estimated using EViews software, and was used to come up with relevant insights. Empirical findings suggest the following: population growth, remittances, and labor force participation are insignificant factors for sustainable growth. On the other hand, previous levels of GDP, trade, and foreign direct investments (FDIs) appear to be relevant for the predictor. This research provides up-to-date conclusions, which can be considered during the decision-making process of central banks, as well as by government policymakers.

scholarly journals The Role of Artificial Intelligence in Fighting the COVID-19 Pandemic

2021 ◽  
Author(s):  
Francesco Piccialli ◽  
Vincenzo Schiano di Cola ◽  
Fabio Giampaolo ◽  
Salvatore Cuomo
Keyword(s):  
Artificial Intelligence ◽  
Clinical Trials ◽  
Digital Transformation ◽  
Daily Activities ◽  
Commercial Vehicles ◽  
Human Skills ◽  
To Come ◽  
Complex Scenario ◽  
The Impact

AbstractThe first few months of 2020 have profoundly changed the way we live our lives and carry out our daily activities. Although the widespread use of futuristic robotaxis and self-driving commercial vehicles has not yet become a reality, the COVID-19 pandemic has dramatically accelerated the adoption of Artificial Intelligence (AI) in different fields. We have witnessed the equivalent of two years of digital transformation compressed into just a few months. Whether it is in tracing epidemiological peaks or in transacting contactless payments, the impact of these developments has been almost immediate, and a window has opened up on what is to come. Here we analyze and discuss how AI can support us in facing the ongoing pandemic. Despite the numerous and undeniable contributions of AI, clinical trials and human skills are still required. Even if different strategies have been developed in different states worldwide, the fight against the pandemic seems to have found everywhere a valuable ally in AI, a global and open-source tool capable of providing assistance in this health emergency. A careful AI application would enable us to operate within this complex scenario involving healthcare, society and research.

scholarly journals Identification of Dynamic Parameters of Pedestrian Walking Model Based on a Coupled Pedestrian–Structure System

2021 ◽  
Vol 11 (14) ◽  
pp. 6407
Author(s):  
Huiqi Liang ◽  
Wenbo Xie ◽  
Peizi Wei ◽  
Dehao Ai ◽  
Zhiqiang Zhang
Keyword(s):  
Negative Correlation ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Field Testing ◽  
The Body ◽  
Structural Vibration ◽  
Pedestrian Dynamics ◽  
Structure Interaction ◽  
Mass Spring ◽  
Stiffness And Damping

As human occupancy has an enormous effect on the dynamics of light, flexible, large-span, low-damping structures, which are sensitive to human-induced vibrations, it is essential to investigate the effects of pedestrian–structure interaction. The single-degree-of-freedom (SDOF) mass–spring–damping (MSD) model, the simplest dynamical model that considers how pedestrian mass, stiffness and damping impact the dynamic properties of structures, is widely used in civil engineering. With field testing methods and the SDOF MSD model, this study obtained pedestrian dynamics parameters from measured data of the properties of both empty structures and structures with pedestrian occupancy. The parameters identification procedure involved individuals at four walking frequencies. Body frequency is positively correlated to the walking frequency, while a negative correlation is observed between the body damping ratio and the walking frequency. The test results further show a negative correlation between the pedestrian’s frequency and his/her weight, but no significant correlation exists between one’s damping ratio and weight. The findings provide a reference for structural vibration serviceability assessments that would consider pedestrian–structure interaction effects.

scholarly journals Impact of Cross-Tie Properties on the Modal Behavior of Cable Networks on Cable-Stayed Bridges

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Javaid Ahmad ◽  
Shaohong Cheng ◽  
Faouzi Ghrib
Keyword(s):  
Analytical Model ◽  
Design Parameters ◽  
Reference Base ◽  
Cable Network ◽  
Cable Networks ◽  
Modal Behavior ◽  
Stiffness And Damping ◽  
Main Cables ◽  
The Impact ◽  
Selection Of

Dynamic behaviour of cable networks is highly dependent on the installation location, stiffness, and damping of cross-ties. Thus, these are the important design parameters for a cable network. While the effects of the former two on the network response have been investigated to some extent in the past, the impact of cross-tie damping has rarely been addressed. To comprehend our knowledge of mechanics associated with cable networks, in the current study, an analytical model of a cable network will be proposed by taking into account both cross-tie stiffness and damping. In addition, the damping property of main cables in the network will also be considered in the formulation. This would allow exploring not only the effectiveness of a cross-tie design on enhancing the in-plane stiffness of a constituted cable network, but also its energy dissipation capacity. The proposed analytical model will be applied to networks with different configurations. The influence of cross-tie stiffness and damping on the modal response of various types of networks will be investigated by using the corresponding undamped rigid cross-tie network as a reference base. Results will provide valuable information on the selection of cross-tie properties to achieve more effective cable vibration control.

High Performance MEMS Thermal Gyroscope

2012 ◽  
Author(s):  
Nilgoon Zarei ◽  
Albert M. Leung ◽  
John D. Jones
Keyword(s):  
External Force ◽  
High Performance ◽  
Gas Flow ◽  
Element Model ◽  
Minimal Impact ◽  
Mems Gyroscope ◽  
Force Finding ◽  
Dimensional Finite Element ◽  
To Come ◽  
The Impact

This paper reports modeling a new design of Thermal MEMS gyroscope through the use of the Comsol Multiphysics software package. Being very small and having no movable parts have made thermal MEMS gyroscope very practical. Previously designed Thermal MEMS gyroscope shows some limitation such as being vulnerable to gravity force. Finding a technique to increase the range of thermal MEMS gyroscope reliability motivated us to come up with a new design that we will refer to as the ‘Forced Convection MEMS gyroscope’. A two-dimensional finite-element model of the device has been developed to investigate its performance. An external force has been introduced to the system to create a higher-velocity hot gas stream that will be deviated more in response to rotation. The external force should be great enough that convection currents resulting from gravity or acceleration will have minimal impact on the gyroscope sensitivity. A heating element can still be used, but its primary purpose is now to warm the flowing gas so that it can be detected by the sensors. In this paper we will also show that, in order to completely eliminate the impact of gravity and increase the sensitivity of the gyroscope, it is possible to eliminate the heaters entirely and instead use heated sensors to detect gas currents. In other words, the sensors are working as hot-wire anemometers. Our simulations suggest that this design variant results in higher sensitivity. We have also carried out optimization studies to identify the best location for the heaters and sensors. A prototype of this device has been fabricated based on MEMS techniques, and an external pump is used to produce an oscillating gas flow within the device.

Translation, interpreting and the genealogy of conflict

2012 ◽  
Vol 11 (2) ◽  
pp. 169-184 ◽  
Author(s):  
Luis Pérez-González
Keyword(s):  
Special Issue ◽  
Social Phenomena ◽  
The Public ◽  
Institutional Settings ◽  
Public Consciousness ◽  
The Media ◽  
Methodological Approaches ◽  
To Come ◽  
The Stability ◽  
The Impact

While the growing ubiquitousness of translation and interpreting has established these activities more firmly in the public consciousness, the extent of the translators’ and interpreters’ contribution to the continued functioning of cosmopolitan and participatory postmodern societies remains largely misunderstood. This paper argues that the theorisation of translation and interpretation as social phenomena and of translators/interpreters as agents contributing to the stability or subversion of social structures through their capacity to re-define the context in which they mediate constitutes a recent development in the evolution of the discipline. The consequentiality of the mediators’ agency, one of the most significant insights to come out of this new body of research, is particularly evident in situations of social, political and cultural confrontation. It is contended that this conceptualisation of agency opens up the possibility of translation being used not only to resolve conflict and tension, but also to promote them. Through a variety of theoretical and methodological approaches, the contributing authors to this special issue explore a number of sites of linguistic and cultural mediation across a range of institutional settings and textual/interactional genres, with particular emphasis on the contribution of translation and interpreting to the genealogy of conflict. The papers presented here address a number of overlapping themes, including the dialectics of governmental policy-making and translation, the interface between translation, politics and the media, the impact of the narrative affiliation of translators and interpreters as agents of mediation, the frictional dynamics of interpreter-mediated institutional encounters and the dynamics of identity negotiation.

Coaching skills for recovery a decade of providing coaching skills for recovery training at a healthcare NHS foundation trust

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Helen Kathryn Cyrus
Keyword(s):  
Work Practice ◽  
Clinical Approach ◽  
Personal Recovery ◽  
Content Type ◽  
Coaching Skills ◽  
The Difference ◽  
To Come ◽  
The Individual ◽  
The Impact ◽  
The Brain

Purpose Overview of coaching for recovery. The paper aims to show an overview of work that was carried out over 11 years with groups of mental health and physical staff. As the facilitator who had run this course for the duration in Nottingham, this was an excellent opportunity to be at the forefront of a brand new project. Design/methodology/approach The introduction of the skills are taught over two consecutive days followed by a further day a month later. The idea of coaching is to be enabled to find the answers in themselves by the use of powerful questions and using the technique of the grow model, combined with practice enables the brain to come up with its own answers. Using rapport and enabling effective communication to deliver the outcome. Findings Evidence from staff/clients and the purpose of the paper shows that when you step back it allows the individual patients/staff to allow the brain to process to create to come up with their solutions, which then helps them to buy into the process and creates ownership. Research limitations/implications The evidence suggests that the approach that was there prior to the course was very much a clinical approach to working with clients and treating the person, administering medication and not focussing on the inner person or personal recovery. The staff review has shown that in the clinical context change is happening from the inside out. Practical implications “Helps change culture”; “change of work practice”; “it changed staff focus – not so prescriptive”; “powerful questions let clients come to their own conclusions”; “coaching gives the ability to find half full. Helps to offer reassurance and to find one spark of hope”. Social implications This has shown that the approach is now person-centred/holistic. This has been the “difference that has made the difference”. When this paper looks at the issues from a different angle in this case a coaching approach, applying technique, knowledge and powerful questions the results have changed. The same clients, same staff and same problems but with the use of a different approach, there is the evidence of a different outcome, which speaks for itself. The coaching method is more facilitative, therefore it illicit’s a different response, and therefore, result. Originality/value The results/evidence starts with the individual attending and their commitment to the process over the two-day course. Then going away for the four weeks/six for managers and a commitment again to practice. Returning to share the impact if any with the group. This, in turn, helps to inspire and gain motivation from the feedback to go back to work invigorated to keep going.

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