Reducing the Complexity When Modelling Damping in Vibrating Systems

2012 ◽  
Author(s):  
Hugh Goyder
Keyword(s):  
Computer Simulations ◽  
Computer Model ◽  
Relative Velocity ◽  
Frequency Response Function ◽  
Usual Method ◽  
Theoretical Interest ◽  
Frequency Spectra ◽  
Computer Based ◽  
Vibrating Systems ◽  
Electrical Theory

If a frequency spectra or frequency response function is known for a structure what physical model can be generated to represent it? This is an important question for computer based simulations where a translation must be made between a spectra and a computer model. This is particularly difficult if damping is to be modelled. Investigation of electrical theory shows that this problem has been examined in detail due to the need to construct circuits that have specific spectra. However, before ideas can be borrowed from electrical theory it is necessary to develop vibration theory so that it aligns perfectly with electrical theory. To achieve this a method for representing mass is suggested which is a generalisation of the usual method and involves using a system of levers so that force is equal to mass times the derivative of relative velocity rather than absolute velocity. It is then shown that following electrical theory a damped spectra may be represented by an undamped sequence of masses and springs terminated by just one dashpot. Such a model is of considerable theoretical interest as well as having utility in computer simulations.

Learning physiology from cardiac surgery patients.

1998 ◽  
Vol 274 (6) ◽  
pp. S74
Author(s):  
S Nicol ◽  
C Narkowicz
Keyword(s):  
Cardiac Surgery ◽  
Computer Simulations ◽  
Clinical Data ◽  
Great Reduction ◽  
Animal Experiments ◽  
Medical Schools ◽  
Physiological Data ◽  
Video Clips ◽  
Computer Based

A number of pressures have led to a very great reduction or complete abandonment of the use of animals in the teaching of physiology in most medical schools. Often animal experiments have been replaced by computer simulations, but a simulation is only as good as the model or algorithm on which it is based and can never contain the depth of information or unpredictability displayed by real animals or patients. We used a computer-based system to collect cardiovascular data from patients instrumented for cardiac surgery, allowing students to "replay" an operation. These recordings were annotated with notes, diagrams and video clips, and a student workbook was written. The resulting package contained a wealth of physiological data and was perceived by students to be very clinically relevant. The very wealth of information, however, tended to overwhelm students, and so a series of introductory Computer tutorials were written to provide students with the background necessary to cope with the clinical data.

Managerial Computer Business Games

2011 ◽  
pp. 1513-1520
Author(s):  
Luigi Proserpio ◽  
Massimo Magni ◽  
Bernardino Provera
Keyword(s):  
Computer Simulations ◽  
Video Data ◽  
Organizational Capabilities ◽  
Learning Theories ◽  
Current Debate ◽  
Living Room ◽  
Temporal Dimension ◽  
Support Tools ◽  
Project Phases ◽  
Computer Based

Interview with Anthony Davidson, SuperAguri F1 GP Driver (autosport.com, March 2, 2007): Q: Can you actually learn anything from the [F1 videogame] though? AD: Absolutely. When I did the 2004 season, I really relied on having video data from the team and using the PlayStation games as well to learn the circuits. We always deal in corner numbers, we don’t use the proper corner names, so we have a little map in the car with the numbers. For you to visualize it beforehand is a help, because when they talk about a bump in turn three then you know what they are talking about before you have even walked the circuit or seen any onboard footage. You know roughly what the track looks like and when you get out there you smile because it is exactly what you were doing in your living room. And now the graphics have stepped up another level it is so much more realistic. F1 drivers can benefit from computer simulations, with a supplement of training before racing on a newly built circuit, with no consolidated knowledge. Managers (and students, too) can benefit from PC-based simulations that recreate complex business worlds as well. Books contain theories, along with a good number of examples. Computer-based business games can add dynamism and a temporal dimension to the standard managerial theories contained in books. Many researchers think that the potential of the computer as a learning tool is very high if we involve the user in a simulation process, instead of giving him a description of reality. This theory is confirmed by many field examples, as shown before by the Formula 1 pilot, who adopts a particular software in order to learn how to drive on a circuit that he has not tested directly. U.S. Marines play Quake and Unreal to simulate the mission in which they will be involved. Business games, finally, start to be adopted in managerial education as learning support tools. For example, EIS simulation has been developed at Insead Business School in order to simulate organizational change, while FirmReality has been developed at Bocconi University to study the integrated use of organizational capabilities to gain competitive advantage. Scientific and managerial literatures recognize the potential of these instruments for learning purposes (compatible with andragogical and collaborative learning theories), but cannot address their design and the integration within distance-learning practices. The current debate on computer simulations involves the research and the standardization of rules for the project phases, in order to take advantage of the potential attributed to this tool, and enhance the compatibility between managers/students and this form of learning.

Phase Transitions of Granular Systems: Between Brazilian Nut Effect and its Reversed Mode

2011 ◽  
Author(s):  
Zi’ang Xie ◽  
Ping Wu ◽  
Shiping Zhang ◽  
Chao Jia ◽  
Weili Wang
Keyword(s):  
Phase Transitions ◽  
Resonance Frequency ◽  
Mass Distribution ◽  
Computer Simulations ◽  
Dynamic Equilibrium ◽  
Granular Systems ◽  
Resonance Behavior ◽  
Particle Parameters ◽  
Equilibrium Separation ◽  
Vibrating Systems

Granular particles with diameters 3mm, 6mm and 0.6mm, of the same density 0.9g/cm3 and the same total weight 100g in vertically vibrating systems were studied. The transition processes of granular systems from Reversed Brazilian Nut (RBN) Effect to Brazilian Nut (BN) Effect at varied conditions, including different vibrating frequencies, amplitudes, and particles sizes, together with computer simulations were investigated. We have observed experimentally that BN Effect or RBN Effect was appeared at certain particle parameters and vibrating conditions, and discussed in five aspects: dynamic equilibrium, separation mode, convection modes, mass distribution and resonance frequency. The results indicate that the upsurge of granular convection and resonance behavior during the processes plays an important role in phase transitions.

Room Acoustic Modelling Techniques: A Comparison of a Scale Model and a Computer Model for a New Opera Theatre

2011 ◽  
Vol 18 (3-4) ◽  
pp. 259-280 ◽  
Author(s):  
Jens Holger Rindel
Keyword(s):  
Satisfactory Agreement ◽  
Computer Simulations ◽  
Computer Model ◽  
Computer Modelling ◽  
Computer Models ◽  
Scale Model ◽  
Acoustic Design ◽  
Acoustic Modelling ◽  
Scale Modelling ◽  
Modelling Techniques

Today most acoustic consultants are using room acoustic computer models as a basis for their acoustic design. However, room acoustic scale modelling is still being used for the design in some major projects, although the costs and the time needed are significantly larger than those related to computer modelling. Both techniques were used by the author in a project for a new opera theatre; first the acoustical design was based on computer simulations using the Odeon software, and next a 1:20 scale model was built and tested. In the paper the results obtained with the two different modelling techniques are compared, and in general a satisfactory agreement has been found. The advantages and drawbacks related to each of the modelling techniques are discussed.

Towards Computer-Based Microstructure Models for Cement-Based Systems

1986 ◽  
Vol 85 ◽  
Author(s):  
Hamlin M. Jennings
Keyword(s):  
Computer Model ◽  
Specific Problem ◽  
Computer Models ◽  
Scientific Basis ◽  
Incremental Change ◽  
Important Development ◽  
Computer Based

ABSTRACTComputer-based models represent an important development that should provide a scientific basis for in-depth predictions of the behavior of materials. Aspects of microstructure models for cement-based systems are described. A computer model is described that can incorporate many assumptions in the form of sub-models. Specific algorithms are selected to solve specific parts of the problem. The algorithm chosen depends on specific problem requirements at each stage of calculation, and these problem requirements may not be anticipated in advance. An important part of these computer models is that they incorporate a file of numbers, representing the microstructure, which can be operated on to effect an incremental change in the system.

Computers in Physician Licensure and Certification: New Methods of Assessment

1994 ◽  
Vol 10 (2) ◽  
pp. 161-171
Author(s):  
John Norcini
Keyword(s):  
Computer Simulations ◽  
Clinical Skills ◽  
Standardized Patients ◽  
Certification Program ◽  
New Methods ◽  
Continuous Testing ◽  
Computerized Tests ◽  
Computer Based ◽  
Item Presentation ◽  
Made In

The newer methods of assessment that could become part of a licensure or certification program for physicians in the next decade include standardized patients which assess clinical skills and four computer-based methods that provide an assessment of cognitive ability: simple computerized tests, computer simulations, adapting item presentation, and continuous testing. The prognosis for standardized patients is mixed, with implementation more likely to occur outside of the U.S. Over the next five years, simple computerized tests will be implemented and significant strides will be made in computer simulations and adapting item presentations. These two methods should be implemented toward the end of the decade. The prognosis for the use of continuous testing is poor because so much fundamental work is needed.

scholarly journals Computer simulations for biological aging and sexual reproduction

2001 ◽  
Vol 73 (1) ◽  
pp. 18-32 ◽  
Author(s):  
DIETRICH STAUFFER ◽  
PAULO M.C. DE OLIVEIRA ◽  
SUZANA MOSS DE OLIVEIRA ◽  
THADEU J.P. PENNA ◽  
JORGE S. SÁ MARTINS
Keyword(s):  
Monte Carlo ◽  
Population Dynamics ◽  
Sexual Reproduction ◽  
Computer Simulations ◽  
Computer Model ◽  
Monte Carlo Methods ◽  
Mutation Accumulation ◽  
Biological Aging ◽  
Penna Model ◽  
Theory Of Aging

The sexual version of the Penna model of biological aging, simulated since 1996, is compared here with alternative forms of reproduction as well as with models not involving aging. In particular we want to check how sexual forms of life could have evolved and won over earlier asexual forms hundreds of million years ago. This computer model is based on the mutation-accumulation theory of aging, using bits-strings to represent the genome. Its population dynamics is studied by Monte Carlo methods.

Manoeuvring Times, Domains and Arenas

1983 ◽  
Vol 36 (2) ◽  
pp. 324-328 ◽  
Author(s):  
B. A. Colley ◽  
R. G. Curtis ◽  
C. T. Stockel
Keyword(s):  
Mathematical Modelling ◽  
Collision Avoidance ◽  
Computer Model ◽  
Relative Velocity ◽  
Avoidance Manoeuvre ◽  
Stationary Objects ◽  
Computer Analyses ◽  
Ship Tracks ◽  
Radar Simulator

Two main concepts in mathematical modelling of ship encounters have been proposed by Davis. The first, the ‘domain’, was an adaptation of a concept originally introduced by Goodwin, who defined the domain as the ‘area about own-ship that a navigator wished to keep free with respect to ships and other stationary objects’. The second, the ‘arena’, conceived by Davis, is the area around the domain which when infringed causes the mariner to consider whether to make a collision-avoidance manoeuvre. Thus, in a computer model, when a vessel enters the arena the computer analyses the situation and, depending on the severity of the threat, makes a collision-avoidance manoeuvre.Goodwin's domain was divided into three sectors corresponding to the ‘giveway’, the ‘stand-on’ and the ‘overtaking’ regions as defined by the relative velocity of approach. The domain was derived from radar films of ship tracks and records of radar simulator experiments. Davis smoothed the sectored domain to a circle with own-ship off-centred astern and to port, and the weighting of each of the sectors retained. Davis's domain had a solid theoretical grounding; the arena, however, was simply a larger version of the smoothed domain. Its size and position were obtained by means of a well-distributed questionnaire. It served its purpose in the model, but lacked any real validation.One problem with the Davis arena was its inability automatically to take into account different velocities, both of own-ship and of targets.

scholarly journals A Computer Model of Drafting Effects on Collective Behavior in Elite 10,000-m Runners

2017 ◽  
Vol 12 (3) ◽  
pp. 345-350 ◽  
Author(s):  
Hugh Trenchard ◽  
Andrew Renfree ◽  
Derek M. Peters
Keyword(s):  
Computer Simulations ◽  
Computer Model ◽  
Collective Behavior ◽  
Energy Savings ◽  
Performance Data ◽  
The Other ◽  
Psychological Processes ◽  
Collective Behaviors

Purpose:Drafting in cycling influences collective behavior of pelotons. Although evidence for collective behavior in competitive running events exists, it is not clear if this results from energetic savings conferred by drafting. This study modeled the effects of drafting on behavior in elite 10,000-m runners.Methods:Using performance data from a men’s elite 10,000-m track running event, computer simulations were constructed using Netlogo 5.1 to test the effects of 3 different drafting quantities on collective behavior: no drafting, drafting to 3 m behind with up to ~8% energy savings (a realistic running draft), and drafting up to 3 m behind with up to 38% energy savings (a realistic cycling draft). Three measures of collective behavior were analyzed in each condition: mean speed, mean group stretch (distance between first- and last-placed runner), and runner-convergence ratio (RCR), which represents the degree of drafting benefit obtained by the follower in a pair of coupled runners.Results:Mean speeds were 6.32 ± 0.28, 5.57 ± 0.18, and 5.51 ± 0.13 m/s in the cycling-draft, runner-draft, and no-draft conditions, respectively (all P < .001). RCR was lower in the cycling-draft condition but did not differ between the other 2. Mean stretch did not differ between conditions.Conclusions:Collective behaviors observed in running events cannot be fully explained through energetic savings conferred by realistic drafting benefits. They may therefore result from other, possibly psychological, processes. The benefits or otherwise of engaging in such behavior are as yet unclear.

Sign in / Sign up

Export Citation Format

Share Document