Worklife Expectancies of Railroad Workers Based on the Twenty-Seventh Actuarial Valuation Using Competing Risks/Multiple Decrement Theory and the Markov Railroad Model

2020 ◽  
Author(s):  
James E. Ciecka ◽  
Gary R. Skoog
Keyword(s):  
Competing Risks ◽  
Web Site ◽  
Weighted Average ◽  
Statistical Characteristics ◽  
Accurate Calculation ◽  
Railroad Workers ◽  
Forensic Economics ◽  
Standard Deviations ◽  
Years Of Service

Abstract This paper contains worklife expectancies (WLE) of railroad workers based on the Twenty-Seventh Actuarial Valuation (Bureau of the Actuary, 2018), thereby updating the previous study of railroad workers' WLE based on the Twenty-Fifth Actuarial Valuation (Bureau of the Actuary, 2012). The main results of this paper are shown in a set of tables.11The tables in this paper provide worklife expectancies and standard deviations for every five years of service and five years of age and are referred to as abridged tables. Readers may interpolate as appropriate—e.g., a 23-year-old railroader would have a 60%/40% weighted average between the age 25 and age 20 entries. In addition, a more accurate calculation is available. The Association of American Railroads has requested that we provide it with complete unabridged tables that may be distributed to its members and posted on its web site. We have done so under a contract with the Association of American Railroads, which provides that those unabridged tables may be posted on the Journal of Forensic Economics web site. They appear there as supplemental materials to this paper, along with other supplemental content which includes Excel worksheets and additional statistical characteristics.

STATISTICAL CHARACTERISTICS OF SLANT ANGLES IN HANDWRITTEN NUMERAL STRINGS AND EFFECTS OF SLANT CORRECTION ON SEGMENTATION

2010 ◽  
Vol 24 (01) ◽  
pp. 97-116 ◽  
Author(s):  
JAVAD SADRI ◽  
CHING Y. SUEN ◽  
TIEN D. BUI
Keyword(s):  
Efficient Method ◽  
Weighted Average ◽  
Correction Method ◽  
Statistical Characteristics ◽  
Geometric Features ◽  
Correction Algorithm ◽  
Connected Component ◽  
Slant Angle ◽  
Segmentation Accuracy ◽  
First Time

A novel and efficient method for correction of slant angles in handwritten numeral strings is proposed. For the first time, the statistical distribution of slant angles in handwritten numerals is investigated and the effects of slant correction on the segmentation of handwritten numeral strings are shown. In our proposed slant correction method, utilizing geometric features, a Component Slant Angle (CSA) is estimated for each connected component independently. A weighted average is then used to compute the String Slant Angle (SSA), which is applied uniformly to correct the slant of all the components in numeral strings. Our experimental results have revealed novel statistics for slant angles of handwritten numeral strings, and also showed that slant correction can significantly improve extraction of segmentation features and segmentation accuracy of touching numerals. Comparison between our slant correction algorithm and similar algorithms in the literature show that our algorithm is more efficient, and on average it has a faster running time.

Predictability of strong motions from the Northridge, California, earthquake

1996 ◽  
Vol 86 (1B) ◽  
pp. S100-S114 ◽  
Author(s):  
John G. Anderson ◽  
Guang Yu
Keyword(s):  
Vertical Component ◽  
Source Model ◽  
Statistical Characteristics ◽  
Peak Acceleration ◽  
Blind Test ◽  
Peak Displacement ◽  
Velocity Models ◽  
Maximum Bias ◽  
Standard Deviations ◽  
A Site

Abstract The composite source model for generating synthetic strong ground motions is tested for its ability to predict the statistical characteristics of Northridge accelerograms recorded in or adjacent to the San Fernando valley. The general problem is prediction of strong motions at a site of engineering interest with sufficient realism to be useful for engineering applications. The strongest test of any proposed method is a blind prediction. For this study, a completely blind test was not possible. Our objective was to use only a preliminary description of fault geometry and magnitude and previously published velocity models and, without iteration to improve the quality of fit, to evaluate the differences between predicted and observed accelerograms. The parameters that we predict are peak acceleration, peak velocity, peak displacement, Fourier spectra at seven frequencies, and pseudorelative velocity response (5% damping) at seven periods. Our results are given for 14 stations. For the horizontal components, these parameters are all predicted with a maximum bias of under 50% and an average bias of observations exceeding predictions by 6%. For peak acceleration and some response spectral periods, the bias for this model is smaller than at least some regressions, when applied to this specific earthquake. On the vertical component, the maximum bias is a factor of 2, and the average gives predictions exceeding observations by 25%. Standard deviations of the common logarithm of the ratio of observed-to-predicted parameters are typically about 0.3, which is perhaps 50% greater than the standard deviations typical of regressions but comparable to standard deviations of observations from this earthquake compared to regressions. In the future, it is likely that, in some cases, traditional regressions will be replaced with synthetic calculations of some type, such as the method used here. Based on the results of this study, the amount of progress that has been made in obtaining that goal is very encouraging.

A Bayes Continuous Reliability Growth Model with Two Categories of Failures

1997 ◽  
Vol 04 (01) ◽  
pp. 1-15
Author(s):  
Daming Lin ◽  
W. K. Chiu
Keyword(s):  
Competing Risks ◽  
Growth Model ◽  
Prior Distribution ◽  
Hazard Rate ◽  
Failure Modes ◽  
Weighted Average ◽  
Hazard Rates ◽  
Development Phase ◽  
Reliability Growth ◽  
Time Invariant

A Bayesian continuous reliability growth model is presented. It is assumed that the development phase of a product consists of m stages. In each stage, the failure mechanism of the product follows a competing risks model with two specific failure modes: inherent and assignable-cause. The hazard rate for each mode is time-invariant within one stage. Under the assumption that modifications of the product improve its reliability, we assign a reasonable joint prior distribution for the hazard rates. Then Bayesian analysis is carried out using this prior distribution. It turns out that the posterior pdf of the hazard rates of interest is just a weighted average of pdf's which have the same form as the prior pdf. A numerical example is given for illustration.

scholarly journals Worklife Expectancy via Competing Risks/Multiple Decrement Theory with an Application to Railroad Workers

2006 ◽  
Vol 19 (3) ◽  
pp. 243-260 ◽  
Author(s):  
Gary R. Skoog ◽  
James E. Ciecka
Keyword(s):  
Competing Risks ◽  
Railroad Workers

Abstract No abstract available.

scholarly journals Building Earthquake Damage Analysis Using Terrestrial Laser Scanning Data

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Qisong Jiao ◽  
Hongbo Jiang ◽  
Qiang Li
Keyword(s):  
Laser Scanning ◽  
Three Dimensional ◽  
Weighted Average ◽  
Terrestrial Laser Scanning ◽  
Earthquake Damage ◽  
Damage Analysis ◽  
Dispersion Parameters ◽  
Center Point ◽  
Damage Extent ◽  
Standard Deviations

Terrestrial laser scanners (TLSs) can acquire high-precision three-dimensional point cloud data for earthquake-damaged buildings. In this study, we collected TLS data in the Wenchuan earthquake zone and developed the TLS-BSAM (terrestrial laser scanning-based building shape analysis model) to carry out a building earthquake damage analysis. This model involves equidistance polygon array extraction, shape dispersion parameter calculations, irregular building clustering segmentation, and damage analysis. We chose 21 buildings as samples for the experiments. The results show that when using an equidistance polygon array to depict a three-dimensional building, 0.5 m is a reasonable sampling interval for building earthquake damage analysis. Using certain characteristic parameters to carry out K-means clustering, one can efficiently divide irregular buildings into regular blocks. Then, by weighted averages, the shape dispersion parameters can be calculated to express the damage extent to buildings. Among the shape dispersion parameters, at least the weighted average standard deviations of the tilt direction, rectangularity, compactness, and center point are suitable to reflect the damage extent. Higher values reflect more serious damage. On the basis of existing data, the weighted average standard deviations of the tilt direction and center point can be used to establish discriminant functions that can effectively distinguish the damage extent.

Ground Motion Prediction Equations for the Vertical Ground Motion Component Based on the NGA-W2 Database

2017 ◽  
Vol 33 (2) ◽  
pp. 499-528 ◽  
Author(s):  
Zeynep Gülerce ◽  
Ronnie Kamai ◽  
Norman A. Abrahamson ◽  
Walter J. Silva
Keyword(s):  
Ground Motion ◽  
Site Response ◽  
Vertical Component ◽  
Weighted Average ◽  
Motion Models ◽  
Nonlinear Site Response ◽  
Vertical Ground Motion ◽  
Vertical Ground ◽  
Standard Deviations ◽  
Ground Motion Models

Empirical ground motion models for the vertical component from shallow crustal earthquakes in active tectonic regions are derived using the PEER NGA-West2 database. The model is applicable to magnitudes 3.0–8.0, distances of 0–300 km, and spectral periods of 0–10 s. The model input parameters are the same as used by Abrahamson et al. (2014) except that the nonlinear site response and depth to bedrock effects are evaluated but found to be insignificant. Regional differences in large distance attenuation and site amplification scaling between California, Japan, China, Taiwan, Italy, and the Middle East are included. Scaling for the hanging-wall effect is incorporated using the constraints from numerical simulations by Donahue and Abrahamson (2014) . The standard deviation is magnitude dependent with smaller magnitudes leading to larger standard deviations at short periods but smaller standard deviations at long periods. The vertical ground motion model developed in this study can be paired with the horizontal component model proposed by Abrahamson et al. (2014) to produce a V/H ratio. For applications where the horizontal spectrum is derived from the weighted average of several horizontal ground motion models, a V/H model derived directly from the V/H data (such as Gülerce and Abrahamson 2011 ) should be preferred.

scholarly journals Statistical Characteristics of Raindrop Size Distribution during Rainy Seasons in Northwest China

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yong Zeng ◽  
Lianmei Yang ◽  
Zepeng Tong ◽  
Yufei Jiang ◽  
Zuyi Zhang ◽  
...  
Keyword(s):  
Size Distribution ◽  
Arid Regions ◽  
Weighted Average ◽  
Northwest China ◽  
Rainfall Rate ◽  
Statistical Characteristics ◽  
Stratiform Rain ◽  
Convective Rain ◽  
Raindrop Size Distribution ◽  
Raindrop Size

Raindrop size distribution (DSD) is of great significance for understanding the microphysical process of rainfall and the quantitative precipitation estimation (QPE). However, in the past, there was a lack of relevant research on Xinjiang in the arid region of northwest China. In this study, the rainy season data collected by the disdrometer in the Yining area of Xinjiang were used for more than two years, and the characteristics of DSDs for all samples, for two rain types (convective and stratiform), and for six different rain rates were studied. The results showed that nearly 70% of the total samples had a rainfall rate of less than 1 mm·h−1, the convective rain was neither continental nor maritime, and there was a clear boundary between convective rain and stratiform rain in terms of the scattergram of the standardized intercept parameter ( log 10 N w ) versus the mass-weighted average diameter ( D m ). When the raindrop diameter was less than 0.7 mm, DSDs of the two rainfalls basically coincided, while when the raindrop diameter was greater than 0.7 mm, DSDs of convective rainfall were located above the stratiform rain. As the rainfall rate increased, D m increased, while log 10 N w first increased and then decreased. In addition, we deduced the Z − R (radar reflectivity-rain rate) relationship and μ − Λ relationship (shape parameter-slope parameter of the gamma DSDs) suitable for the Yining area. These conclusions are conducive to strengthening the understanding of rainfall microphysical processes in arid regions and improving the ability of QPE in arid regions.

Worklife Expectancy of Railroad Workers Based on the Twenty-Fifth Actuarial Valuation Using Both Competing Risks/Multiple Decrement Theory and the Markov Railroad Model

2014 ◽  
Vol 25 (2) ◽  
pp. 109-127 ◽  
Author(s):  
Gary R. Skoog ◽  
James E. Ciecka
Keyword(s):  
Markov Process ◽  
Markov Model ◽  
Competing Risks ◽  
Process Model ◽  
Railroad Workers ◽  
Retirement Plan ◽  
Markov Process Model ◽  
Probability Mass ◽  
Mass Functions ◽  
Current Report

Abstract The U. S. Railroad Retirement Board's Bureau of the Actuary publishes valuations of the retirement plan for railroad workers every three years. The most current report, the Twenty-Fifth Actuarial Valuation, released in August 2012 covers the years 2008-10. We use data on mortality, disability retirements, age retirements, and other final withdrawals contained in the Technical Supplement of this valuation to estimate worklife expectancies (WLE) of railroad workers. There are substantial changes in WLE when compared to WLE based on the Twenty-Third Actuarial Valuation and the Twenty-Fourth Valuation. We identify the sources of these changes. In addition to WLE, we estimate entire probability mass functions and provide summary measures of distributional characteristics of time spent in railroad work. Our main results use a competing risks/multiple decrement model, but we also provide WLE based on the railroad Markov process model and show that the former model is also a Markov model, albeit a different Markov model from the railroad Markov model.

scholarly journals EVALUATING THE EFFECTS OF REDUCTIONS IN LiDAR DATA ON THE VISUAL AND STATISTICAL CHARACTERISTICS OF THE CREATED DIGITAL ELEVATION MODELS

2016 ◽  
Vol III-2 ◽  
pp. 91-98 ◽  
Author(s):  
F. F. Asal
Keyword(s):  
Point Cloud ◽  
Digital Elevation Models ◽  
Statistical Characteristics ◽  
Lidar Data ◽  
High Point ◽  
Digital Elevation ◽  
Data Density ◽  
Standard Deviations ◽  
Dem Accuracy ◽  
Data Reductions

With continuous developments in LiDAR technologies high point cloud densities have been attainable but accompanied by challenges for processing big volumes of data. Reductions in high point cloud densities are expected to lower data acquisition and data processing costs; however this could affect the characteristics of the generated Digital Elevation Models (DEMs). This research aimed to evaluate the effects of reductions in airborne LiDAR point cloud data densities on the visual and statistical characteristics of the generated DEMs. DEMs have been created from a dataset which constitutes last returns of raw LiDAR data that was acquired at bare lands for Gilmer County, USA between March and April 2004, where qualitative and quantitative testing analyses have been performed. Visual analysis has shown that the DEM can withstand a considerable degree of quality with reduced densities down to 0.128&thinsp;pts/m<sup>2</sup> (47&thinsp;% of the data remaining), however degradations in the DEM visual characteristics appeared in coarser tones and rougher textures have occurred with more reductions. Additionally, the statistical analysis has indicated that the standard deviations of the DEM elevations have decreased by only 22&thinsp;% of the total decrease with data density reductions down to 0.101&thinsp;pts/m<sup>2</sup> (37&thinsp;% of the data remaining) while greater rate of decreasing in the standard deviations has occurred with more reductions referring to greater rate of surface smoothing and elevation approximating. Furthermore, the accuracy analysis testing has given that the DEM accuracy has degraded by only 4.83&thinsp;% of the total degradations with data density reductions down to 0.128&thinsp;pts/m<sup>2</sup>, however great deteriorations in the DEM accuracy have occurred with more data reductions. Finally, it is recommended that LiDAR data can withstand point density reductions down to 0.128&thinsp;pts/m<sup>2</sup> (about 50&thinsp;% of the data) without big deteriorations in the visual and statistical characteristics of the generated DEMs.

Genetic parameters forNematodirusspp. egg counts in Romney lambs in New Zealand

2004 ◽  
Vol 79 (1) ◽  
pp. 33-39 ◽  
Author(s):  
C. A. Morris ◽  
A. Bisset ◽  
A. Vlassoff ◽  
C. J. West ◽  
M. Wheeler
Keyword(s):  
Genetic Correlations ◽  
Selection Criterion ◽  
Weighted Average ◽  
Breeding Lines ◽  
Faecal Egg Count ◽  
Genetic Mechanisms ◽  
Resistance To Infection ◽  
Selection For ◽  
Standard Deviations ◽  
Sampling Times

AbstractGenetic analyses were carried out on Nematodirus spp. egg counts (NEM) of lambs from a set of Romney breeding lines. The lines had been under selection for 22 seasons (1979 to 2000) for divergence in resistance to infection by strongyle nematodes other than NEM, using faecal egg count (FEC) as the selection criterion. Heritabilities and genetic correlations for NEM were estimated using residual maximum likelihood procedures. Correlated responses in NEM were also determined. Heritability estimates for loge(NEM + 100) in lambs at 4 months of age (NEM1) or 6 months of age (NEM2) were 0·15 (s.e. 0·03) and 0·26 (s.e. 0·04) respectively (c.f. 0·28 (s.e. 0·02) and 0·35 (s.e. 0·02) for loge(FEC + 100)). The genetic correlation between loge(NEM1 + 100) and loge(NEM2 + 100) was 0·85 (s.e. 0·08), while the genetic correlations between measurements of loge(NEM + 100) and loge(FEC + 100) on both sampling occasions had a weighted average of 0·43, with estimates ranging from 0·30 (s.e. 0·08) to 0·52 (s.e. 0·07). Divergence in loge(NEM + 100) between the high and low FEC lines, estimated over both sampling times combined, was 1·07 phenotypic standard deviations, compared with 3·6 phenotypic standard deviations for loge(FEC + 100). Expressed in terms of back-transformed eggs per g, the high and low FEC lines differed by factors of 7·6 and 32·2 for NEM and FEC, respectively. The results support earlier parasitological data indicating that the genetic mechanisms in sheep which are responsible for resistance to other strongyle nematodes probably also influence resistance to Nematodirus infection.

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