A scheme for expressing instrumental responses parametrically

1977 ◽  
Vol 67 (3) ◽  
pp. 957-969 ◽  
Author(s):  
Peter C. Luh

abstract This study shows that, provided a seismic instrument as a whole behaves linearly over its response range, and provided its phase response is known accurately, the instrumental responses can be parametrically expressed in terms of transfer functions of linear systems. The scheme is based on the observation that knowing accurately the detailed overall amplitude and phase responses of a linear instrument is tantamount to knowing all the pertinent constants for the construction of its overall transfer function. Because of generally poor quality of empirical phase calibrations, empirical phases are substituted by minimum phases, calculated via a Hilbert transform of amplitude response. Application of the scheme to actual SRO (LP) and USGS (SP) instruments resulted in sufficiently close agreements between parametric and actual responses to warrant the utility of the scheme.

Mathematics ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 17 ◽  
Author(s):  
Yanhong Feng ◽  
Haizhong An ◽  
Xiangyun Gao

Moth search (MS) algorithm, originally proposed to solve continuous optimization problems, is a novel bio-inspired metaheuristic algorithm. At present, there seems to be little concern about using MS to solve discrete optimization problems. One of the most common and efficient ways to discretize MS is to use a transfer function, which is in charge of mapping a continuous search space to a discrete search space. In this paper, twelve transfer functions divided into three families, S-shaped (named S1, S2, S3, and S4), V-shaped (named V1, V2, V3, and V4), and other shapes (named O1, O2, O3, and O4), are combined with MS, and then twelve discrete versions MS algorithms are proposed for solving set-union knapsack problem (SUKP). Three groups of fifteen SUKP instances are employed to evaluate the importance of these transfer functions. The results show that O4 is the best transfer function when combined with MS to solve SUKP. Meanwhile, the importance of the transfer function in terms of improving the quality of solutions and convergence rate is demonstrated as well.


1972 ◽  
Vol 62 (6) ◽  
pp. 1665-1672 ◽  
Author(s):  
P. M. Bolduc ◽  
R. M. Ellis ◽  
R. D. Russell

abstract Determination of the phase response of a minimum-phase seismic system directly from the amplitude response by the Hilbert transform is investigated. The error by this technique is found to be less than 2° with the major source of inaccuracy being the uncertainties in the amplitude data. This technique is useful for rapid determination of the phase response if the amplitude response is known.


2014 ◽  
Vol 11 (4) ◽  
pp. 181-196 ◽  
Author(s):  
Lyudmyla L. Barannyk ◽  
Hazem A. Aboutaleb ◽  
Aicha Elshabini ◽  
Fred Barlow

We present a method for checking causality of band-limited tabulated frequency responses. The approach is based on Kramers-Krönig relations and construction of periodic polynomial continuations. Kramers-Krönig relations, also known as dispersion relations, represent the fact that real and imaginary parts of a causal function form a Hilbert transform pair. The Hilbert transform is defined on an infinite domain, while, in practice, discrete values of transfer functions that represent high-speed interconnects are available only on a finite frequency interval. Truncating the computational domain or approximating the behavior of the transfer function at infinity causes significant errors at the boundary of the given frequency band. The proposed approach constructs a periodic polynomial continuation of the transfer function that is defined by raw frequency responses on the original frequency interval and by a polynomial in the extended domain, and requires the continuation to be periodic on a wider domain of a finite length and smooth at the boundary. The dispersion relations are computed spectrally using fast Fourier transform and inverse fast Fourier transform routines applied to periodic continuations. The technique does not require the knowledge or approximation of the transfer function behavior at infinity. The method significantly reduces the boundary artifacts that are due to the lack of out-of-band frequency responses, and is capable of detecting small, smooth causality violations. We perform the error analysis of the method and show that its accuracy and sensitivity depend on the smoothness and accuracy of data and a polynomial continuation. The method can be used to verify and enforce causality before the frequency responses are employed for macromodeling. The performance of the method is tested on several analytic and simulated examples.


Author(s):  
Peter Rez

In high resolution microscopy the image amplitude is given by the convolution of the specimen exit surface wave function and the microscope objective lens transfer function. This is usually done by multiplying the wave function and the transfer function in reciprocal space and integrating over the effective aperture. For very thin specimens the scattering can be represented by a weak phase object and the amplitude observed in the image plane is1where fe (Θ) is the electron scattering factor, r is a postition variable, Θ a scattering angle and x(Θ) the lens transfer function. x(Θ) is given by2where Cs is the objective lens spherical aberration coefficient, the wavelength, and f the defocus.We shall consider one dimensional scattering that might arise from a cross sectional specimen containing disordered planes of a heavy element stacked in a regular sequence among planes of lighter elements. In a direction parallel to the disordered planes there will be a continuous distribution of scattering angle.


2020 ◽  
pp. 34-36
Author(s):  
M. A. Pokhaznikova ◽  
E. A. Andreeva ◽  
O. Yu. Kuznetsova

The article discusses the experience of teaching and conducting spirometry of general practitioners as part of the RESPECT study (RESearch on the PrEvalence and the diagnosis of COPD and its Tobacco-related aetiology). A total of 33 trained in spirometry general practitioners performed a study of 3119 patients. Quality criteria met 84.1% of spirometric studies. The analysis of the most common mistakes made by doctors during the forced expiratory maneuver is included. The most frequent errors were expiration exhalation of less than 6s (54%), non-maximal effort throughout the test and lack of reproducibility (11.3%). Independent predictors of poor spirogram quality were male gender, obstruction (FEV1 /FVC<0.7), and the center where the study was performed. The number of good-quality spirograms ranged from 96.1% (95% CI 83.2–110.4) to 59.8% (95% CI 49.6–71.4) depending on the center. Subsequently, an analysis of the reasons behind the poor quality of research in individual centers was conducted and the identified shortcomings were eliminated. The poor quality of the spirograms was associated either with the errors of the doctors who undertook the study or with the technical malfunctions of the spirometer.


2012 ◽  
Vol 37 (4) ◽  
pp. 447-454
Author(s):  
James W. Beauchamp

Abstract Source/filter models have frequently been used to model sound production of the vocal apparatus and musical instruments. Beginning in 1968, in an effort to measure the transfer function (i.e., transmission response or filter characteristic) of a trombone while being played by expert musicians, sound pressure signals from the mouthpiece and the trombone bell output were recorded in an anechoic room and then subjected to harmonic spectrum analysis. Output/input ratios of the signals’ harmonic amplitudes plotted vs. harmonic frequency then became points on the trombone’s transfer function. The first such recordings were made on analog 1/4 inch stereo magnetic tape. In 2000 digital recordings of trombone mouthpiece and anechoic output signals were made that provide a more accurate measurement of the trombone filter characteristic. Results show that the filter is a high-pass type with a cutoff frequency around 1000 Hz. Whereas the characteristic below cutoff is quite stable, above cutoff it is extremely variable, depending on level. In addition, measurements made using a swept-sine-wave system in 1972 verified the high-pass behavior, but they also showed a series of resonances whose minima correspond to the harmonic frequencies which occur under performance conditions. For frequencies below cutoff the two types of measurements corresponded well, but above cutoff there was a considerable difference. The general effect is that output harmonics above cutoff are greater than would be expected from linear filter theory, and this effect becomes stronger as input pressure increases. In the 1990s and early 2000s this nonlinear effect was verified by theory and measurements which showed that nonlinear propagation takes place in the trombone, causing a wave steepening effect at high amplitudes, thus increasing the relative strengths of the upper harmonics.


2019 ◽  
Vol 7 (3) ◽  
pp. 232-237
Author(s):  
Hana Larasati ◽  
Theresia Titin Marlina

Background: stroke is a disorder of nervous system function that occurs suddenly and is caused by brain bleeding disorders that can affect the quality of life physical dimensions, social dimensions, psychological dimensions, environmental dimensions. Based on the result of Lumbu study (2015) the number of samples were 71 people collected data using the (WHOQOL-BREF). There were 56 people (78,9%) had the poor quality of life of post stroke. The mean of post-stroke quality of life domain was physical domain (45,27%), psychological domain (49,87%), social relations domain (48,15%) and environmental domain (50.01%). Objective: the purpose of the study was know the quality of life of the stroke patients in Outpatient Polyclinic of Private Hospital in Yogyakarta. Methods: used descriptive quantitative by using questionnaire test of purposive sampling system based on patients who have been affected of ischemic or hemorrhagic stroke before, number 30 respondents. Result: quality of life of stroke patient of medium physical dimension (67%), psychological dimension (71%), social dimension (67%), dimension good environment (63%). Conclusion: the quality of life of stroke patients of physical dimension, psychological dimension, and moderate social dimension, while the quality of life of stroke patients were good environmental dimension.   Keywords: Hemorrhagic stroke, ischemic stroke, quality of life


2020 ◽  
pp. 3-53
Author(s):  
Yu.B. Vinslav

The article analyzes the main indicators of the evolution of the domestic economy and its industrial complex in the past year (in January — November 2019). It Identifies trends in this evolution, including negative trends that determine the preservation of reproductive threats in 2020: sluggishness, instability and low quality of economic growth. The main reasons for the fact that the objective resource capabilities of the macro level were clearly not used enough to effectively solve the urgent problems of technological modernization of the economy and increase people’s welfare are established. The main reason is the poor quality of public administration, including imperfect strategic planning and industrial policy; there is still no modern national innovation system in the country. Accordingly, recommendations for improving the quality of state regulation in its specified components are justified. The recommended measures, according to the author, will help the economy to move to a trajectory of rapid, sustainable and high-quality growth.


2020 ◽  
Vol 27 (1) ◽  
pp. 106-120 ◽  
Author(s):  
L. A. Rodionova ◽  
E. D. Kopnova

The relevance of the chosen topic is closely related to the development of a system for monitoring the implementation of the May Presidential Decree (2018) to increase life expectancy and improve the quality of life of the population. It has been stated that despite the positive dynamics of life expectancy over the past decade, Russia still has a huge regional differentiation (16,6 years for women, 18,2 years for men in 2016) and an average gender gap - 10,6 years. The choice of factors affecting the gender gap in life expectancy in Russian regions is supported by a conclusion most common in foreign studies that climatic conditions, living conditions, the quality of food and drinking water, alcohol consumption are essential components of public health and life expectancy.The article provides an overview of studies on assessment factors of life expectancy, presents the authors’ approach to identifying gender gaps in life expectancy, living conditions, and lifestyle affecting the indicator of life expectancy. The paper presents the results of a comparative analysis of gender gap in life expectancy in Russia and foreign countries. The paper studies the correlation between living conditions and lifestyle, and life expectancy.Classification of the regions by the life expectancy at birth for men and women is an important component of this study. The authors used Rosstat data for 2016 and the k-means method to select three clusters of Russian regions taking into account gender, living conditions and lifestyle. The paper identifies similar health problems of the regions that are associated with alcohol consumption, poor nutrition and poor quality of drinking water, poor housing and living conditions. The lowest life expectancy rates for men and women are recorded in regions of the 1st cluster (Jewish Autonomous Region, Republic of Tuva, Chukotka Autonomous Area). High mortality rates are a result of external causes. There is a poor quality of drinking water and poor nutrition, excessive alcohol consumption, and inadequate housing conditions.Based on the obtained results were determined possible reserves for reducing the gender and regional differentiation of life expectancy.


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