Comparative Analysis of Time-Frequency Curves of Seismic Records on Liquefied and Non-Liquefied Sites

The frequency of ground records on liquefied and non-liquefied sites is different. The calculation method of frequency decreasing rate is given here and the division line between liquefied and non-liquefied sites is proposed. To analyze the time-frequency curves of acceleration, the zero-crossing method is employed. The soft sites and ordinary non-liquefied sites are included in non-liquefied sites. The results show: (1) The concept and calculation method of frequency decreasing ratio, which is proposed in this paper, can describe the characteristics and regulations of time-frequency on liquefied and non-liquefied sites; (2) Before peak ground acceleration (PGA), the difference of the average frequencies of acceleration on liquefied and non-liquefied sites is not obvious and the average frequency of acceleration on soft sites is smaller than that either on liquefied or non-liquefied sites; (3) After PGA, the average frequency of acceleration on ordinary non-liquefied sites is the highest in the three types of sites, that of soft sites is the middle and that of liquefied sites is the smallest; (4) If the absolute change of the time-frequency is used as the criteria, it will be confused between soft sites and liquefied sites; (5) The threshold value of frequency decreasing ratio is 0.5 between liquefied and non-liquefied sites, which can judge the liquefied sites, non-liquefied sites and soft sites correctly.

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Costs and the cost-effectiveness threshold

10.1093/oso/9780198794837.003.0019 ◽

2017 ◽

Author(s):

Jan Abel Olsen

Keyword(s):

Societal Perspective ◽

Threshold Value ◽

Quality Adjusted Life Year ◽

Healthcare Sector ◽

The Difference ◽

The Cost ◽

Qaly Threshold ◽

Cost Effectiveness Threshold ◽

Effectiveness Threshold ◽

Quality Adjusted Life

Chapter 19 starts by distinguishing between the two contrasting perspectives that an economic evaluation would take: the healthcare sector perspective versus the societal perspective. The former is considered a ‘narrow analysis’ which includes only the costs accruing within the healthcare sector, while the latter represents a ‘broad analysis’ that accounts for all resource implications in all sectors of the economy. After an investigation into various types of costs, a ‘limited societal perspective’ is suggested to be more appropriate than either of the two ‘extreme perspectives’. The chapter continues with a discussion of the cost per quality-adjusted life year (QALY) threshold and explains the difference between a demand side- versus a supply-side approach to determining a threshold value for a QALY.

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Multivariate empirical mode decomposition–based structural damage localization using limited sensors

Journal of Vibration and Control ◽

10.1177/10775463211006965 ◽

2021 ◽

pp. 107754632110069

Author(s):

Sandeep Sony ◽

Ayan Sadhu

Keyword(s):

Empirical Mode Decomposition ◽

Structural Damage ◽

Cost Effective ◽

Threshold Value ◽

Damage Localization ◽

Time Frequency ◽

Multivariate Empirical Mode Decomposition ◽

Percentage Difference ◽

Mode Decomposition

In this article, multivariate empirical mode decomposition is proposed for damage localization in structures using limited measurements. Multivariate empirical mode decomposition is first used to decompose the acceleration responses into their mono-component modal responses. The major contributing modal responses are then used to evaluate the modal energy for the respective modes. A damage localization feature is proposed by calculating the percentage difference in the modal energies of damaged and undamaged structures, followed by the determination of the threshold value of the feature. The feature of the specific sensor location exceeding the threshold value is finally used to identify the location of structural damage. The proposed method is validated using a suite of numerical and full-scale studies. The validation is further explored using various limited measurement cases for evaluating the feasibility of using a fewer number of sensors to enable cost-effective structural health monitoring. The results show the capability of the proposed method in identifying as minimal as 2% change in global modal parameters of structures, outperforming the existing time–frequency methods to delineate such minor global damage.

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Modeling and Performance Evaluation of Precise Positioning and Time-Frequency Transfer with Galileo Five-Frequency Observations

Remote Sensing ◽

10.3390/rs13152972 ◽

2021 ◽

Vol 13 (15) ◽

pp. 2972

Author(s):

Wei Xu ◽

Wen-Bin Shen ◽

Cheng-Hui Cai ◽

Li-Hong Li ◽

Lei Wang ◽

...

Keyword(s):

Three Dimensional ◽

Satellite Orbit ◽

Average Frequency ◽

Satellite System ◽

Observation Data ◽

Navigation Satellite ◽

Dual Frequency ◽

Time Frequency ◽

Combination Model ◽

Frequency Transfer

The present Global Navigation Satellite System (GNSS) can provide at least double-frequency observations, and especially the Galileo Navigation Satellite System (Galileo) can provide five-frequency observations for all constellation satellites. In this contribution, precision point positioning (PPP) models with Galileo E1, E5a, E5b, E5 and E6 frequency observations are established, including a dual-frequency (DF) ionospheric-free (IF) combination model, triple-frequency (TF) IF combination model, quad-frequency (QF) IF combination model, four five-frequency (FF) IF com-bination models and an FF uncombined (UC) model. The observation data of five stations for seven days are selected from the multi-GNSS experiment (MGEX) network, forming four time-frequency links ranging from 454.6 km to 5991.2 km. The positioning and time-frequency transfer performances of Galileo multi-frequency PPP are compared and evaluated using GBM (which denotes precise satellite orbit and clock bias products provided by Geo Forschung Zentrum (GFZ)), WUM (which denotes precise satellite orbit and clock bias products provided by Wuhan University (WHU)) and GRG (which denotes precise satellite orbit and clock bias products provided by the Centre National d’Etudes Spatiales (CNES)) precise products. The results show that the performances of the DF, TF, QF and FF PPP models are basically the same, the frequency stabilities of most links can reach sub10−16 level at 120,000 s, and the average three-dimensional (3D) root mean square (RMS) of position and average frequency stability (120,000 s) can reach 1.82 cm and 1.18 × 10−15, respectively. The differences of 3D RMS among all models are within 0.17 cm, and the differences in frequency stabilities (in 120,000 s) among all models are within 0.08 × 10−15. Using the GRG precise product, the solution performance is slightly better than that of the GBM or WUM precise product, the average 3D RMS values obtained using the WUM and GRG precise products are 1.85 cm and 1.77 cm, respectively, and the average frequency stabilities at 120,000 s can reach 1.13 × 10−15 and 1.06 × 10−15, respectively.

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Improved Inpatient Care through Greater Patient–Doctor Contact under the Hospitalist Management Approach: A Real-Time Assessment

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18115718 ◽

2021 ◽

Vol 18 (11) ◽

pp. 5718

Author(s):

Wonjeong Chae ◽

Dong-Woo Choi ◽

Eun-Cheol Park ◽

Sung-In Jang

Keyword(s):

Contact Time ◽

Inpatient Care ◽

Average Frequency ◽

Care Quality ◽

Management Approach ◽

Regression Analyses ◽

Contact Duration ◽

Inpatient Ward ◽

The Difference ◽

Attending Physician

Objective: To examine the difference between hospitalist and non-hospitalist frequency of patient–doctor contact, duration of contact, cumulative contact time, and the amount of time taken by the doctor to resolve an issue in response to a medical call. Research Design and Measures: Data from 18 facilities and 36 wards (18 hospitalist wards and 18 non-hospitalist wards) were collected. The patient–doctor contact slip and medical call response slips were given to each inpatient ward to record. A total of 28,926 contacts occurred with 2990 patients, and a total of 8435 medical call responses occurred with 3329 patients. Multivariate logistic regression analyses and regression analyses were used for statistical analyses. Results: The average frequency of patient–doctor contact during a hospital stay was 10.0 times per patient for hospitalist patients. Using regression analyses, hospitalist patients had more contact with the attending physician (β = 5.6, standard error (SE) = 0.28, p < 0.0001). Based on cumulative contact time, hospitalists spent significantly more time with the patient (β = 32.29, SE = 1.54, p < 0.0001). After a medical call to resolve the issue, doctors who took longer than 10 min were 4.14 times (95% CI 3.15–5.44) and those who took longer than 30 min were 4.96 times (95% CI 2.75–8.95) more likely to be non-hospitalists than hospitalists. Conclusion: This study found that hospitalists devoted more time to having frequent encounters with patients. Therefore, inpatient care by a hospitalist who manages inpatient care from admission to discharge could improve the care quality.

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The Fehleranalyse Error Analysis of Fully Characteristic Curve of Pump to Be Nominalization and Study for the Influence on Result of Hydraulic Transients Calculation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.250-253.3696 ◽

2011 ◽

Vol 250-253 ◽

pp. 3696-3701

Author(s):

Yu Si Yang ◽

Ru Dong ◽

Jie Gao

Keyword(s):

Error Analysis ◽

Calculation Method ◽

Similarity Theory ◽

Characteristic Curve ◽

Water Hammer ◽

Engineering Project ◽

Real Situation ◽

Numeric Calculation ◽

Specific Speed ◽

The Difference

In this paper，by transforming the fully characteristic curve of pump with eighty specific speed to be numeralization he obtained fehleranalyse error of discrete data were analyzed based on the pump similarity theory and the difference between certain assumed condition and real situation in numeralization process. Then the influence of the fehleranalyse error of numeralization method on the pressure boost caused by Pump-off water hammer was computed by a Pump-off water hammer calculation within an real engineering project. The reliability of numeric calculation method of fully characteristic curve of Pump is proved.

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HOW TO OBTAIN A GLOBAL REFERENCE THRESHOLD IN AHP/ANP

International Journal of the Analytic Hierarchy Process ◽

10.13033/ijahp.v13i1.802 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Claudio Garuti

Keyword(s):

Real Life ◽

Absolute Measurement ◽

Threshold Value ◽

Rate Of Change ◽

Current Status ◽

Medical Diagnoses ◽

Specific Objective ◽

Global Threshold ◽

Disaster Assessment ◽

The Difference

This paper has two main objectives. The first objective is to provide a mathematically grounded technique to construct local and global thresholds using the well-known rate of change method. The next objective, which is secondary, is to show the relevance and possibilities of applying the AHP/ANP in absolute measurement (AM) compared to the relative measurement (RM) mode, which is currently widely used in the AHP/ANP community. The ability to construct a global threshold would help increase the use of AHP/ANP in the AM mode (rating mode) in the AHP/ANP community. Therefore, if the first specific objective is achieved, it would facilitate reaching the second, more general objective. For this purpose, a real-life example based on the construction of a multi-criteria index and threshold will be described. The index measures the degree of lag of a neighborhood through the Urban and Social Deterioration Index (USDI) based on an AHP risks model. The global threshold represents the tolerable lag value for the specific neighborhood. The difference or gap between the neighborhood’s current status (actual USDI value) and this threshold represents the level of neighborhood deterioration that must be addressed to close the gap from a social and urban standpoint. The global threshold value is a composition of 45 terminal criteria with their own local threshold that must be evaluated for the specific neighborhood. This example is the most recent in a large list of AHP applications in AM mode in vastly different decision making fields, such as risk disaster assessment, environmental assessment, the problem of medical diagnoses, social responsibility problems, BOCR analysis for the evolution of nuclear energy in Chile in the next 20 years and many others. (See list of projects in Appendix).

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Great Salt Lake–Effect Precipitation: Observed Frequency, Characteristics, and Associated Environmental Factors

Weather and Forecasting ◽

10.1175/waf-d-12-00016.1 ◽

2012 ◽

Vol 27 (4) ◽

pp. 954-971 ◽

Cited By ~ 27

Author(s):

Trevor I. Alcott ◽

W. James Steenburgh ◽

Neil F. Laird

Keyword(s):

Environmental Factors ◽

Temperature Difference ◽

Large Scale ◽

Salt Lake ◽

Great Salt Lake ◽

Threshold Value ◽

Substantial Improvement ◽

Lake Area ◽

Lake Effect ◽

The Difference

Abstract This climatology examines the environmental factors controlling the frequency, occurrence, and morphology of Great Salt Lake–effect (GSLE) precipitation events using cool season (16 September–15 May) Weather Surveillance Radar-1988 Doppler (WSR-88D) imagery, radiosonde soundings, and MesoWest surface observations from 1997/98 to 2009/10. During this period, the frequency of GSLE events features considerable interannual variability that is more strongly correlated to large-scale circulation changes than lake-area variations. Events are most frequent in fall and spring, with a minimum in January when the climatological lake surface temperature is lowest. Although forecasters commonly use a 16°C lake–700-hPa temperature difference (ΔT) as a threshold for GSLE occurrence, GSLE was found to occur in winter when ΔT was only 12.4°C. Conversely, GSLE is associated with much higher values of ΔT in the fall and spring. Therefore, a seasonally varying threshold based on a quadratic fit to the monthly minimum ΔT values during GSLE events is more appropriate than a single threshold value. A probabilistic forecast method based on the difference between ΔT and this seasonally varying threshold, 850–700-hPa relative humidity, and 700-hPa wind direction offers substantial improvement over existing methods, although forecast skill is diminished by temperature and moisture errors in operational models. An important consideration for forecasting because of their higher precipitation rates, banded features—with a horizontal aspect ratio of 6:1 or greater—dominate only 20% of the time that GSLE is occurring, while widespread, nonbanded precipitation is much more common. Banded periods are associated with stronger low-level winds and a larger lake–land temperature difference.

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Dynamic Characteristics of Gear Coupling and Rotor System in Transmission Process Considering Misalignment and Tooth Contact Analysis

Processes ◽

10.3390/pr8111336 ◽

2020 ◽

Vol 8 (11) ◽

pp. 1336

Author(s):

Wei Fan ◽

Hong Lu ◽

Yongquan Zhang ◽

Xiangang Su

Keyword(s):

Finite Element ◽

Dynamic Model ◽

Calculation Method ◽

High Speed ◽

Low Frequency ◽

Rotor System ◽

Integral Approach ◽

Time Frequency ◽

Low Frequency Vibration ◽

Mass Eccentricity

The dynamic vibration of the gear coupling-rotor system (GCRS) caused by misalignment is an important factor of low frequency vibration and noise radiation of the naval marine. The axial misalignment of gear coupling is inevitable owing to mass eccentricity, and is unconstrained in axial direction at high-speed operation. Therefore, the dynamic model of GCRS is proposed, considering gear-coupling misalignment and contact force in this paper. The whole motion differential equation of GCRS is established based on the finite element method. Moreover, the numerical calculation method of meshing force, considering the uniform distribution load on contact surface, is presented, and the mathematical predictive time–frequency characteristics are analyzed by the Newmark stepwise integral approach. Finally, a reduced-scale application of the propulsion shaft system is utilized to validate the effectiveness of the proposed dynamic model. For the sensibility to low-frequency vibration, the natural frequencies and vibration modes of GCRS are analyzed through the processing and analysis of acceleration signal. The experimental dynamic response and main components of vibration are respectively consistent with mathematical results, which demonstrate the effectiveness of the proposed dynamic model of GCRS with misalignment. Furthermore, it also shows that the proposed finite element analysis and calculation method are suitable for complex shafting, providing a novel thought for dynamic analysis of the propeller–shaft–hull coupled system of marine.

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A Joint Model of Production and Preventive Maintenance Plan

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.156-157.18 ◽

2010 ◽

Vol 156-157 ◽

pp. 18-23

Author(s):

Zhi Qiang Lu ◽

Yue Jun Zhang

Keyword(s):

System Reliability ◽

Preventive Maintenance ◽

Lot Sizing ◽

Threshold Value ◽

Joint Model ◽

Production Plan ◽

Lot Sizing Problem ◽

Capacitated Lot Sizing ◽

The Difference ◽

Maintenance Plan

We integrated run-based preventive maintenance (PM) into the production plan at the tactical level. The production plan was based on the single level capacitated lot-sizing problem (CLSP). We assumed the system reliability should be kept above certain threshold value to ensure the feasibility of the production plan; the reliability would be affected only by system running. Thus, PM would be triggered by the reliability requirement and the accumulated running time. We established this relationship as a nonlinear integer constraint in the joint model. We also proposed a branch and bound algorithm using CPLEX to solve the model. Finally, a numerical example was given to illustrate the difference between run-based and time-based PM.

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