scholarly journals A New Spectral Shape-Based Record Selection Approach UsingNpand Genetic Algorithms

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Edén Bojórquez ◽  
Alfredo Reyes-Salazar ◽  
Sonia E. Ruiz ◽  
Juan Bojórquez
Keyword(s):  
Genetic Algorithms ◽  
Traditional Approach ◽  
Nonlinear Dynamic Analysis ◽  
Response Spectra ◽  
Spectral Shape ◽  
Optimization Approach ◽  
Design Spectrum ◽  
Target Spectrum ◽  
The Mean ◽  
Record Selection

With the aim to improve code-based real records selection criteria, an approach inspired in a parameter proxy of spectral shape, namedNp, is analyzed. The procedure is based on several objectives aimed to minimize the record-to-record variability of the ground motions selected for seismic structural assessment. In order to select the best ground motion set of records to be used as an input for nonlinear dynamic analysis, an optimization approach is applied using genetic algorithms focuse on finding the set of records more compatible with a target spectrum and targetNpvalues. The results of the newNp-based approach suggest that the real accelerograms obtained with this procedure, reduce the scatter of the response spectra as compared with the traditional approach; furthermore, the mean spectrum of the set of records is very similar to the target seismic design spectrum in the range of interest periods, and at the same time, similarNpvalues are obtained for the selected records and the target spectrum.

scholarly journals Investigation of the Impact of Seed Record Selection on Structural Response

2010 ◽  
Author(s):  
Thomas W. Houston ◽  
Greg E. Mertz ◽  
Michael C. Costantino ◽  
Carl J. Costantino
Keyword(s):  
Transfer Functions ◽  
Structural Response ◽  
Time History ◽  
Response Spectra ◽  
Recent Experience ◽  
Target Response ◽  
Target Spectrum ◽  
Time Histories ◽  
Record Selection ◽  
The Impact

Time history records are typically used to define the seismic demand for critical structures for which soil structure interaction (SSI) analyses are often required. Criteria for the development of time histories is provided in ASCE 43-05. The time histories are based on a close fit of 5% damped target response spectra. Recent experience has demonstrated that for cases where the transfer functions associated with the structural response are narrow, the ASCE 43-05 criteria can under-predict peak spectral responses in the structure by as much as 70% in some frequency ranges. One potential solution for this issue is to reinstate requirements for matching target response spectra for multiple damping levels to ASCE 43-05 criteria. However, recent probabilistic seismic hazard analyses (PSHA) do not generally contain spectra for multiple damping levels. This paper proposes an approach to generate target spectra at multiple damping levels, given the 5% damped target spectrum provided by the PSHA, utilizing catalogs of recorded earthquakes. The process of fitting time histories to multiple damped spectra is effective in correcting defficiencies observed in the computed structural response when time histories meeting the ASCE 43-05 fitting criteria are used.

Selection and Scaling of Ground Motion Time Histories for Structural Design Using Genetic Algorithms

2004 ◽  
Vol 20 (2) ◽  
pp. 413-426 ◽  
Author(s):  
Farzad Naeim ◽  
Arzhang Alimoradi ◽  
Shahram Pezeshk
Keyword(s):  
Ground Motions ◽  
Response Spectra ◽  
Single Individual ◽  
Least Mean Square ◽  
Scaling Factors ◽  
Design Spectrum ◽  
Earthquake Ground Motions ◽  
Earthquake Records ◽  
Target Spectrum ◽  
Scaling Methods

This paper presents a new approach to selection of a set of recorded earthquake ground motions that in combination match a given site-specific design spectrum with minimum alteration. The scaling factors applied to selected ground motions are scalar values within the range specified by the user. As a result, the phase and shape of the response spectra of earthquake ground motions are not tampered with. Contrary to the prevailing scaling methods where a preset number of earthquake records (usually between a single component to seven pairs) are selected first and scaled to match the design spectrum next, the proposed method is capable of searching a set consisting of thousands of earthquake records and recommending a desired subset of records that match the target design spectrum. This task is achieved by using a genetic algorithm (GA), which treats the union of 7 records and corresponding scaling factors as a single “individual.” The first generation of individuals may include a population of, for example, 200 records. Then, through processes that mimic mating, natural selection, and mutation, new generations of individuals are produced and the process continues until an optimum individual (seven pairs and scaling factors) is obtained. The procedure is fast and reliable and results in records that match the target spectrum with minimal tampering and the least mean square of deviation from the target spectrum.

scholarly journals Modeling the Excess Velocity of Low-Viscous Taylor Droplets in Square Microchannels

Fluids ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 162 ◽  
Author(s):  
Thorben Helmers ◽  
Philip Kemper ◽  
Jorg Thöming ◽  
Ulrich Mießner
Keyword(s):  
High Speed ◽  
Process Intensification ◽  
Continuous Phase ◽  
Channel Cross Section ◽  
Optimization Approach ◽  
Mean Flow ◽  
Bypass Flow ◽  
Wall Film ◽  
Proposed Model ◽  
The Mean

Microscopic multiphase flows have gained broad interest due to their capability to transfer processes into new operational windows and achieving significant process intensification. However, the hydrodynamic behavior of Taylor droplets is not yet entirely understood. In this work, we introduce a model to determine the excess velocity of Taylor droplets in square microchannels. This velocity difference between the droplet and the total superficial velocity of the flow has a direct influence on the droplet residence time and is linked to the pressure drop. Since the droplet does not occupy the entire channel cross-section, it enables the continuous phase to bypass the droplet through the corners. A consideration of the continuity equation generally relates the excess velocity to the mean flow velocity. We base the quantification of the bypass flow on a correlation for the droplet cap deformation from its static shape. The cap deformation reveals the forces of the flowing liquids exerted onto the interface and allows estimating the local driving pressure gradient for the bypass flow. The characterizing parameters are identified as the bypass length, the wall film thickness, the viscosity ratio between both phases and the C a number. The proposed model is adapted with a stochastic, metaheuristic optimization approach based on genetic algorithms. In addition, our model was successfully verified with high-speed camera measurements and published empirical data.

scholarly journals Adaptive Gene Level Mutation

Algorithms ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 16
Author(s):  
Jalal Al-afandi ◽  
Horváth András
Keyword(s):  
Genetic Algorithms ◽  
Stochastic Optimization ◽  
Specific Problem ◽  
Traditional Approach ◽  
Fitness Function ◽  
Optimization Methods ◽  
Analytic Solutions ◽  
Problem Representation ◽  
Travelling Salesman ◽  
Gene Level

Genetic Algorithms are stochastic optimization methods where solution candidates, complying to a specific problem representation, are evaluated according to a predefined fitness function. These approaches can provide solutions in various tasks even, where analytic solutions can not be or are too complex to be computed. In this paper we will show, how certain set of problems are partially solvable allowing us to grade segments of a solution individually, which results local and individual tuning of mutation parameters for genes. We will demonstrate the efficiency of our method on the N-Queens and travelling salesman problems where we can demonstrate that our approach always results faster convergence and in most cases a lower error than the traditional approach.

Non-Traditional Applications of near Infrared Spectroscopy Based on the Optical Characteristic Models for a Biological Material Having Cellular Structure

1998 ◽  
Vol 6 (1) ◽  
pp. 41-46 ◽  
Author(s):  
Satoru Tsuchikawa
Keyword(s):  
Biological Material ◽  
Path Length ◽  
Cellular Structure ◽  
Process Model ◽  
Near Infrared ◽  
Traditional Approach ◽  
Nir Spectroscopy ◽  
Optical Path Length ◽  
Optical Path ◽  
The Mean

Non-destructive measurements, based on near infrared (NIR) spectroscopy, on biological material with a cellular structure like wood require a non-traditional approach. We have developed new concepts to model the optical properties of a sample having cellular structure, for the illumination conditions of the spectrometer available to us. A set of optical models, which consisted of the directional characteristics models, the light-path models and the equivalent surface roughness model was proposed to clarify the behaviour of light propagation in a wood sample. Furthermore, the mean optical path length, which was derived by incorporating the nth power cosine model of radiant intensity into the diffusion process model in consideration of the parallel beam component of incident light, was calculated. By introducing the concept of equivalent sample thickness, compatible with the mean optical path length, into the Kubelka–Munk theory, generalised input/output equations for radiation were constructed. In this non-traditional application of NIR spectroscopy, these optical concepts make it possible to analyse both the physical condition and chemical composition of a biological material with a cellular structure.

A Critical Look at the Use of Design Spectrum Shape for Seismic Risk Assessment

2012 ◽  
Vol 28 (4) ◽  
pp. 1711-1721
Author(s):  
Emrah Erduran ◽  
Conrad Lindholm
Keyword(s):  
Numerical Simulations ◽  
Response Spectra ◽  
Ground Motion Prediction Equations ◽  
Ground Motion Prediction ◽  
Design Spectrum ◽  
Spectrum Shape ◽  
Actual Spectrum ◽  
Building Typology ◽  
Actual Response ◽  
Damage Estimates

The effects of using design spectrum shape over actual response spectra on earthquake damage estimates has been investigated. A series of numerical simulations were conducted to estimate the expected damage. The simulations were conducted with four different spectral shapes, two different ground-motion prediction equations (GMPEs) and three different soil classes. As a result of the numerical simulations, it was observed that the use of design spectrum shape leads to over- or underestimation of damage estimates relative to those obtained from the actual spectrum computed using GMPE. The damage estimates were observed to be sensitive to the selected design spectrum shape, the GMPE used to compute the spectral values, the soil type, and the fundamental period of the building typology. It was also observed that Eurocode- and IBC-type design spectrum shapes led to significantly different damage estimates compared to one another.

Correlation between the sea level muon spectrum and the primary nucleon spectrum using the Cocconi–Koester–Perkins model

1979 ◽  
Vol 57 (7) ◽  
pp. 921-925 ◽  
Author(s):  
A. K. Chakrabarti ◽  
A. K. Das ◽  
A. K. De
Keyword(s):  
Sea Level ◽  
Pion Production ◽  
Spectral Shape ◽  
Muon Spectrum ◽  
Proton Proton ◽  
Absolute Value ◽  
Nucleon Spectrum ◽  
Scaling Models ◽  
The Mean ◽  
Good Agreement

Using the recent ISR data of proton–proton interactions on the inclusive production of pions and nucleons, realistic values of the mean pion inelasticity Kπ and the mean nucleon inelasticity KT have been estimated. These values have been used for the derivation of the sea level differential muon spectrum from the primary nucleon spectrum and vice versa using the CKP model as an extension of the work presented in an earlier article. It is found that none of the measured primary nucleon spectra of Ryan, Ormes, and Balasubrahmanyan and Grigorov, Rapoport, and Shestoperov fit any of the precisely measured muon spectra of Ayre, Baxendale, Hume, Nandi, Thompson, and Whalley and Allkofer, Carstensen, and Dau in spectral shape or the absolute value. On the other hand good agreement between the derived muon spectra and the spectra of Allkofer et al. and Ayre et al. is found if the primary nucleon spectra of the forms, N(Ep) = (1.38 ± 0.08)Ep−2.59 and N(Ep) = (1.00 ± 0.10)Ep−2.55, respectively, are assumed. The first form is comparable with that obtained by Brooke, Hayman, Kamiya, and Wolfendale following more approximate but similar procedure. It is also not unjustified when compared with the measured primary all nuclei spectrum of Grigorov et al. in the light of suggestions made by Ellsworth, Ito, Macfall, Siohan, Streitmatter, Tonwar, Vishwanath, Yodh, and Balasubrahmanyan. By comparing the pion production spectra derived from the same primary nucleon spectrum but using the CKP and the scaling models, it is concluded that the results are sensitive to the model assumed for the collisions.

scholarly journals Optimization of the balance between effort and yield in unilateral surgical transfer of mouse embryos

2017 ◽  
Vol 51 (6) ◽  
pp. 622-628 ◽  
Author(s):  
Pablo González-Jara ◽  
Tomás Fontela ◽  
Esther López-Mimbela ◽  
Marta Cereceda ◽  
Daniel Del Olmo ◽  
...  
Keyword(s):  
Embryo Transfer ◽  
Mouse Embryos ◽  
Mouse Strains ◽  
Optimization Approach ◽  
Use Of Resources ◽  
Heterogeneous Nature ◽  
Laboratory Manuals ◽  
The Mean ◽  
Transfer Procedures

Surgical transfer of embryos is carried out daily in animal facilities worldwide for the rederivation of mouse strains/lines, among other purposes. Current protocols described in laboratory manuals recommend using a high number of embryos during transfer, typically in the range of 15 up to 25. To optimize the use of resources it is necessary to estimate and relate the effort required and the yield obtained. Here, we analyse the balance between the number of embryos transferred (the effort), and the yield as the number of born pups obtained from surgical embryo transfer. To accomplish this, we have analyzed data obtained during rederivation of nearly one hundred lines of mice to a new animal facility. Our results confirm that the use of increasing numbers of embryos per transfer increases the yields of born pups, as has been described previously in the literature, but they also highlight the disproportionate effort required, i.e. in the number of embryos that needed to be transferred. An estimate of the mean expected yields of surgical transfers and their comparison with the actual observed yields indicated that the balance between effort and yield is optimized when using lower numbers of embryos than in currently used protocols, in the range of 8 to 12. Given the heterogeneous nature of the data presented and analyzed here, which is from a population of mice that may be considered as representative of any animal facility, our optimization approach should help save resources in similar facilities and improve the yields of embryo transfer procedures.

scholarly journals Genetic Algorithms for Localization in WSN

2020 ◽  
Vol 9 (5) ◽  
pp. 2397-2401
Keyword(s):  
Wireless Sensor Networks ◽  
Genetic Algorithms ◽  
Bat Algorithm ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Localization Error ◽  
Node Localization ◽  
Soft Computing Techniques ◽  
Anchor Nodes ◽  
The Mean

In wireless sensor networks, localization is a way to track the exact location of sensor nodes. Occasionally node localization may not be accurate due to the absence or limitation of anchor nodes. To reduce the mean localization error, soft computing techniques such as BAT and bacterial foraging driven bat algorithm (BDBA) are utilized in literature. For better localization with reduced error, in this paper, firefly driven bat algorithm (FDBA) is proposed, which combines the heuristic of firefly and BAT algorithms. Our proposed FDBA algorithm provides better localization in terms of error of 60% and 40 % less error as compared to BAT and BDBA algorithm, respectively.

Regional propagation characteristics and source parameters of earthquakes in northeastern North America

1994 ◽  
Vol 84 (1) ◽  
pp. 1-15 ◽  
Author(s):  
John Boatwright
Keyword(s):  
Site Response ◽  
Source Parameters ◽  
Low Frequency ◽  
Response Spectra ◽  
Spectral Shape ◽  
Propagation Characteristics ◽  
S Wave ◽  
Data Set ◽  
Wave Trains ◽  
Source Site

Abstract The vertical components of the S wave trains recorded on the Eastern Canadian Telemetered Network (ECTN) from 1980 through 1990 have been spectrally analyzed for source, site, and propagation characteristics. The data set comprises some 1033 recordings of 97 earthquakes whose magnitudes range from M ≈ 3 to 6. The epicentral distances range from 15 to 1000 km, with most of the data set recorded at distances from 200 to 800 km. The recorded S wave trains contain the phases S, SmS, Sn, and Lg and are sampled using windows that increase with distance; the acceleration spectra were analyzed from 1.0 to 10 Hz. To separate the source, site, and propagation characteristics, an inversion for the earthquake corner frequencies, low-frequency levels, and average attenuation parameters is alternated with a regression of residuals onto the set of stations and a grid of 14 distances ranging from 25 to 1000 km. The iteration between these two parts of the inversion converges in about 60 steps. The average attenuation parameters obtained from the inversion were Q = 1997 ± 10 and γ = 0.998 ± 0.003. The most pronounced variation from this average attenuation is a marked deamplification of more than a factor of 2 at 63 km and 2 Hz, which shallows with increasing frequency and increasing distance out to 200 km. The site-response spectra obtained for the ECTN stations are generally flat. The source spectral shape assumed in this inversion provides an adequate spectral model for the smaller events (Mo < 3 × 1021 dyne-cm) in the data set, whose Brune stress drops range from 5 to 150 bars. For the five events in the data set with Mo ≧ 1023 dyne-cm, however, the source spectra obtained by regressing the residuals suggest that an ω2 spectrum is an inadequate model for the spectral shape. In particular, the corner frequencies for most of these large events appear to be split, so that the spectra exhibit an intermediate behavior (where |ü(ω)| is roughly proportional to ω).

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