The approach of evaluating the final scores of multi-criteria decision-making(MCDM)methods according to the strength of association with real-life rankings is interesting for comparing MCDM methods.This approach has r...The approach of evaluating the final scores of multi-criteria decision-making(MCDM)methods according to the strength of association with real-life rankings is interesting for comparing MCDM methods.This approach has recently been applied mostly to financial data.In these studies,where it is emphasized that some methods show more stable success,it would be useful to see the results that will emerge by testing the approach on different data structures more comprehensively.Moreover,not only the final MCDM results but also the performance of normalization techniques and data types(fuzzy or crisp),which are components of MCDM,can be compared using the same approach.These components also have the potential to affect MCDM results directly.In this direction,in our study,the economic performances of G-20(Group of 20)countries,which have different data structures,were calculated over ten different periodic decision matrices.Ten different crisp-based MCDM methods(COPRAS,CODAS,MOORA,TOPSIS,MABAC,VIKOR(S,R,Q),FUCA,and ELECTRE III)with different capabilities were used to better visualize the big picture.The relationships between two different real-life reference anchors and MCDM methods were used as a basis for comparison.The CODAS method develops a high correlation with both anchors in most periods.The most appropriate normalization technique for CODAS was identified using these two anchors.Interestingly,the maximum normalization technique was the most successful among the alternatives(max,min–max,vector,sum,and alternative ranking-based).Moreover,we compared the two main data types by comparing the correlation results of crisp-based and fuzzy-based CODAS.The results were very consistent,and the“Maximum normalization-based fuzzy integrated CODAS procedure”was proposed to decision-makers to measure the economic performance of the countries.展开更多
Coda waves are multiply scattered waves that arrive much later than the major waves. Small seismic velocity variations are observed in reservoirs because of small variations in reservoir properties, which affect the f...Coda waves are multiply scattered waves that arrive much later than the major waves. Small seismic velocity variations are observed in reservoirs because of small variations in reservoir properties, which affect the first arrivals. Hence, first arrivals cannot be used to detect small seismic velocity variations. However, small variations can be reliably detected by the coda waves because of the amplification owing to multiple scattering. We investigate the ability of coda wave interferometry to detect seismic velocity variations and monitor time-lapse reservoir characteristics using numerical simulations and experimental data. We use the Marmousi II model and finite-difference methods to build model seismic data and introduce small seismic velocity variations in the target layer. We examine the model seismic data before and after the changes and observe the coda waves. We find that velocity changes can be detected by coda wave interferometry and demonstrate that coda wave interferometry can be used in monitoring time- lapse reservoir characteristics.展开更多
Two large earthquakes(an earthquake doublet)occurred in south-central Turkey on February 6,2023,causing massive damages and casualties.The magnitudes and the relative sizes of the two mainshocks are essential informat...Two large earthquakes(an earthquake doublet)occurred in south-central Turkey on February 6,2023,causing massive damages and casualties.The magnitudes and the relative sizes of the two mainshocks are essential information for scientific research and public awareness.There are obvious discrepancies among the results that have been reported so far,which may be revised and updated later.Here we applied a novel and reliable long-period coda moment magnitude method to the two large earthquakes.The moment magnitudes(with one standard error)are 7.95±0.013 and 7.86±0.012,respectively,which are larger than all the previous reports.The first mainshock,which matches the largest recorded earthquakes in the Turkish history,is slightly larger than the second one by 0.11±0.035 in magnitude or by 0.04 to 0.18 at 95%confidence level.展开更多
Ultrasonic coda waves are widely usea to stuay hign-trequency scattering, however, ultrasonic coda waves are strongly affected by interference from by boundary-reflected waves. To understand the effect of boundary-ref...Ultrasonic coda waves are widely usea to stuay hign-trequency scattering, however, ultrasonic coda waves are strongly affected by interference from by boundary-reflected waves. To understand the effect of boundary-reflected waves, we performed ultrasonic experiments using aluminum and shale samples, and the rotating staggered-mesh finite-difference method to simulate the wavefield. We analyzed the wavefield characteristics at the different receiving points and the interference characteristics of the boundary-reflected waves with the ultrasonic coda wave, and the effect of sample geometry on the ultrasonic coda waves. The increase in the aspect ratio of the samples delays the interference effect of the laterally reflected waves and reduces the effect on the ultrasonic coda waves. The main waves interfering with the ultrasonic coda waves are laterally reflected PP-, PS-, PPP-, and PPS-waves. The scattering and attenuation of the high-frequency energy in actual rocks can weaken the interference of laterally reflected waves with the ultrasonic coda waves.展开更多
文摘The approach of evaluating the final scores of multi-criteria decision-making(MCDM)methods according to the strength of association with real-life rankings is interesting for comparing MCDM methods.This approach has recently been applied mostly to financial data.In these studies,where it is emphasized that some methods show more stable success,it would be useful to see the results that will emerge by testing the approach on different data structures more comprehensively.Moreover,not only the final MCDM results but also the performance of normalization techniques and data types(fuzzy or crisp),which are components of MCDM,can be compared using the same approach.These components also have the potential to affect MCDM results directly.In this direction,in our study,the economic performances of G-20(Group of 20)countries,which have different data structures,were calculated over ten different periodic decision matrices.Ten different crisp-based MCDM methods(COPRAS,CODAS,MOORA,TOPSIS,MABAC,VIKOR(S,R,Q),FUCA,and ELECTRE III)with different capabilities were used to better visualize the big picture.The relationships between two different real-life reference anchors and MCDM methods were used as a basis for comparison.The CODAS method develops a high correlation with both anchors in most periods.The most appropriate normalization technique for CODAS was identified using these two anchors.Interestingly,the maximum normalization technique was the most successful among the alternatives(max,min–max,vector,sum,and alternative ranking-based).Moreover,we compared the two main data types by comparing the correlation results of crisp-based and fuzzy-based CODAS.The results were very consistent,and the“Maximum normalization-based fuzzy integrated CODAS procedure”was proposed to decision-makers to measure the economic performance of the countries.
基金sponsored by the 973 Program of China(No.2013CB228604)the Natural Science Foundation of Shandong Province(No.ZR2013DQ020)+1 种基金the Fundamental Research Funds for the Central Universities(No.15CX08002A)the National Natural Science Foundation of China(No.41374123)
文摘Coda waves are multiply scattered waves that arrive much later than the major waves. Small seismic velocity variations are observed in reservoirs because of small variations in reservoir properties, which affect the first arrivals. Hence, first arrivals cannot be used to detect small seismic velocity variations. However, small variations can be reliably detected by the coda waves because of the amplification owing to multiple scattering. We investigate the ability of coda wave interferometry to detect seismic velocity variations and monitor time-lapse reservoir characteristics using numerical simulations and experimental data. We use the Marmousi II model and finite-difference methods to build model seismic data and introduce small seismic velocity variations in the target layer. We examine the model seismic data before and after the changes and observe the coda waves. We find that velocity changes can be detected by coda wave interferometry and demonstrate that coda wave interferometry can be used in monitoring time- lapse reservoir characteristics.
基金the National Key R&D Program of China(No.2022YFF0800601)the National Natural Science Foundation of China(No.U1939204).
文摘Two large earthquakes(an earthquake doublet)occurred in south-central Turkey on February 6,2023,causing massive damages and casualties.The magnitudes and the relative sizes of the two mainshocks are essential information for scientific research and public awareness.There are obvious discrepancies among the results that have been reported so far,which may be revised and updated later.Here we applied a novel and reliable long-period coda moment magnitude method to the two large earthquakes.The moment magnitudes(with one standard error)are 7.95±0.013 and 7.86±0.012,respectively,which are larger than all the previous reports.The first mainshock,which matches the largest recorded earthquakes in the Turkish history,is slightly larger than the second one by 0.11±0.035 in magnitude or by 0.04 to 0.18 at 95%confidence level.
基金supported by the Strategic Leading Science and Technology Programme(Class B)of the Chinese Academy of Sciences(No.XDB10010400)
文摘Ultrasonic coda waves are widely usea to stuay hign-trequency scattering, however, ultrasonic coda waves are strongly affected by interference from by boundary-reflected waves. To understand the effect of boundary-reflected waves, we performed ultrasonic experiments using aluminum and shale samples, and the rotating staggered-mesh finite-difference method to simulate the wavefield. We analyzed the wavefield characteristics at the different receiving points and the interference characteristics of the boundary-reflected waves with the ultrasonic coda wave, and the effect of sample geometry on the ultrasonic coda waves. The increase in the aspect ratio of the samples delays the interference effect of the laterally reflected waves and reduces the effect on the ultrasonic coda waves. The main waves interfering with the ultrasonic coda waves are laterally reflected PP-, PS-, PPP-, and PPS-waves. The scattering and attenuation of the high-frequency energy in actual rocks can weaken the interference of laterally reflected waves with the ultrasonic coda waves.
