scholarly journals Correcting 14C Histograms for the Non-Linearity of the Radiocarbon Time Scale

Radiocarbon ◽  
1989 ◽  
Vol 31 (2) ◽  
pp. 169-177 ◽  
Author(s):  
Ad Stolk ◽  
Koos Hogervorst ◽  
Henk Berendsen
Keyword(s):  
Computer Program ◽  
Correction Factor ◽  
Calibration Curve ◽  
Time Scale ◽  
Quantitative Method ◽  
Moving Average ◽  
Large Numbers ◽  
Interval Width ◽  
Reasonable Choice ◽  
Peat Formation

Large numbers of 14C dates of the base and top of Holocene peat layers may be plotted in 14C histograms in order to establish statistically a chronology of periods of essentially clastic sedimentation and peat formation. Due to the non-linearity of the 14C time scale in terms of calendar years, clustering of 14C dates on random peat growth may occur. This seriously hampers the interpretation of histograms. A quantitative method and computer program were developed to correct the histograms for this effect. The correction factor that has to be applied depends on the calibration curve and the interval width of the correction parameter dy. For peat samples, an interval width of 100 14C yr and a calibration curve based on a 100-yr moving average seems to be a reasonable choice.

scholarly journals Calibration of Radiocarbon Ages by Computer

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 805-816 ◽  
Author(s):  
Johannes Van Der Plicht ◽  
W G Mook
Keyword(s):  
Computer Program ◽  
Calibration Curve ◽  
Spline Function ◽  
Moving Average ◽  
Age Distribution ◽  
Automatic Calibration ◽  
Calibration Data ◽  
Average Procedure ◽  
Data Points ◽  
Radiocarbon Calibration

A PC-based computer program for automatic calibration of 14C dates has been developed in Turbo-Pascal (version 4.0). It transforms the Gaussian 14C dating result on the 3σ level into a real calendar age distribution. It uses as a calibration curve a spline function, generated along the calibration data points as published in the Radiocarbon Calibration Issue. Special versions of the code can average several 14C dates into one calibrated result, generate smoothed curves by a moving average procedure and perform wiggle matching.

scholarly journals Reservoir Sizing at Draft Level of 75% of Mean Annual Flow Using Drought Magnitude Based Method on Canadian Rivers

Hydrology ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 79
Author(s):  
Tribeni C. Sharma ◽  
Umed S. Panu
Keyword(s):  
Standard Deviation ◽  
Time Scale ◽  
Moving Average ◽  
Flow Data ◽  
Truncation Level ◽  
Drought Intensity ◽  
Error Margin ◽  
Reservoir Volume ◽  
The Mean ◽  
Reservoir Sizing

On a global basis, there is trend that a majority of reservoirs are sized using a draft of 75% of the mean annual flow (0.75 MAF). The reservoir volumes based on the proposed drought magnitude (DM) method and the sequent peak algorithm (SPA) at 0.75 MAF draft were compared at the annual, monthly and weekly scales using the flow sequences of 25 Canadian rivers. In our assessment, the monthly scale is adequate for such analyses. The DM method, although capable of using flow data at any time scale, has been demonstrated using monthly standardized hydrological index (SHI) sequences. The moving average (MA) smoothing of the monthly SHI sequences formed the basis in the DM method for estimating the reservoir volume through the use of the extreme number theorem, and the hypothesis that drought magnitude is equal to the product of the drought intensity and drought length. The truncation level in the SHI sequences was found as SHIo [ = (0.75 ‒ 1) µo/σo], where µo and σo are the overall mean and standard deviation of the monthly flows. The DM-based estimates for the deficit volumes and the SPA-based reservoir volumes were found comparable within an error margin of ±18%.

scholarly journals CONVERGENCE RATES OF SUMS OF α-MIXING TRIANGULAR ARRAYS: WITH AN APPLICATION TO NONPARAMETRIC DRIFT FUNCTION ESTIMATION OF CONTINUOUS-TIME PROCESSES

2016 ◽  
Vol 33 (5) ◽  
pp. 1121-1153
Author(s):  
Shin Kanaya
Keyword(s):  
Continuous Time ◽  
Convergence Rates ◽  
Moving Average ◽  
Function Estimation ◽  
Triangular Arrays ◽  
Large Numbers ◽  
Strongly Mixing ◽  
Time Distance ◽  
Continuous Time Processes ◽  
Near Unit Root

The convergence rates of the sums of α-mixing (or strongly mixing) triangular arrays of heterogeneous random variables are derived. We pay particular attention to the case where central limit theorems may fail to hold, due to relatively strong time-series dependence and/or the nonexistence of higher-order moments. Several previous studies have presented various versions of laws of large numbers for sequences/triangular arrays, but their convergence rates were not fully investigated. This study is the first to investigate the convergence rates of the sums of α-mixing triangular arrays whose mixing coefficients are permitted to decay arbitrarily slowly. We consider two kinds of asymptotic assumptions: one is that the time distance between adjacent observations is fixed for any sample size n; and the other, called the infill assumption, is that it shrinks to zero as n tends to infinity. Our convergence theorems indicate that an explicit trade-off exists between the rate of convergence and the degree of dependence. While the results under the infill assumption can be seen as a direct extension of those under the fixed-distance assumption, they are new and particularly useful for deriving sharper convergence rates of discretization biases in estimating continuous-time processes from discretely sampled observations. We also discuss some examples to which our results and techniques are useful and applicable: a moving-average process with long lasting past shocks, a continuous-time diffusion process with weak mean reversion, and a near-unit-root process.

scholarly journals A 40,000-Year Varve Chronology from Lake Suigetsu, Japan: Extension of the 14C Calibration Curve

Radiocarbon ◽  
1997 ◽  
Vol 40 (1) ◽  
pp. 505-515 ◽  
Author(s):  
Hiroyuki Kitagawa ◽  
Johannes Van Der Plicht
Keyword(s):  
Tree Ring ◽  
Calibration Curve ◽  
Time Scale ◽  
Mass Spectrometric ◽  
Laminated Sediments ◽  
Varve Chronology ◽  
Total Range ◽  
Dating Method ◽  
Annually Laminated Sediments ◽  
Potential Tool

A sequence of annually laminated sediments is a potential tool for calibrating the radiocarbon time scale beyond the range of the absolute tree-ring calibration (11 ka). We performed accelerator mass spectrometric (AMS) 14C measurements on >250 terrestrial macrofossil samples from a 40,000-yr varve sequence from Lake Suigetsu, Japan. The results yield the first calibration curve for the total range of the 14C dating method.

Spectrographic Calculations with Computerized Emulsion Calibration and Programmable Calculator Computations

1976 ◽  
Vol 30 (2) ◽  
pp. 190-195 ◽  
Author(s):  
D. R. Blevins ◽  
W. R. O'Neill
Keyword(s):  
Computer Program ◽  
Linear Equation ◽  
Calibration Curve ◽  
Graphical Methods ◽  
Calibration Data ◽  
Programmable Calculator ◽  
Element Concentrations ◽  
Program Strategy ◽  
Desk Calculator ◽  
Intensity Ratios

Photographic spectrographic calculations of intensity ratios and the corresponding element concentrations are performed faster and more accurately with programmable desk calculators than by graphical methods. These calculations are facilitated by applying a transform to microphotometer transmittance readings to make them linear with respect to intensity. This transform has the form log [{(100 – T)/ T} {(a + T)/ T}] where a is the transform constant and T is percent transmittance. A FORTRAN computer program strategy is given for calculating the transform constant from emulsion calibration data and obtaining a linear equation for the emulsion calibration curve. This equation is used to program a desk calculator to convert transmittance readings to intensity ratios corrected for background. A second calculator program computes element concentrations from the intensity ratios.

scholarly journals Stochastic slowly adapting ionic currents may provide a decorrelation mechanism for neural oscillators by causing wander in the intrinsic period

2016 ◽  
Vol 116 (3) ◽  
pp. 1189-1198 ◽  
Author(s):  
Sharon E. Norman ◽  
Robert J. Butera ◽  
Carmen C. Canavier
Keyword(s):  
Time Scale ◽  
Moving Average ◽  
Ionic Currents ◽  
Oscillation Period ◽  
General Mechanism ◽  
Slow Time ◽  
Autocorrelation Structure ◽  
Neural Signature ◽  
Random Fluctuations ◽  
Stochastic Adaptation

Oscillatory neurons integrate their synaptic inputs in fundamentally different ways than normally quiescent neurons. We show that the oscillation period of invertebrate endogenous pacemaker neurons wanders, producing random fluctuations in the interspike intervals (ISI) on a time scale of seconds to minutes, which decorrelates pairs of neurons in hybrid circuits constructed using the dynamic clamp. The autocorrelation of the ISI sequence remained high for many ISIs, but the autocorrelation of the ΔISI series had on average a single nonzero value, which was negative at a lag of one interval. We reproduced these results using a simple integrate and fire (IF) model with a stochastic population of channels carrying an adaptation current with a stochastic component that was integrated with a slow time scale, suggesting that a similar population of channels underlies the observed wander in the period. Using autoregressive integrated moving average (ARIMA) models, we found that a single integrator and a single moving average with a negative coefficient could simulate both the experimental data and the IF model. Feeding white noise into an integrator with a slow time constant is sufficient to produce the autocorrelation structure of the ISI series. Moreover, the moving average clearly accounted for the autocorrelation structure of the ΔISI series and is biophysically implemented in the IF model using slow stochastic adaptation. The observed autocorrelation structure may be a neural signature of slow stochastic adaptation, and wander generated in this manner may be a general mechanism for limiting episodes of synchronized activity in the nervous system.

A REMARK ON THE STRONG LAW FOR B-VALUED ARRAYS OF RANDOM ELEMENTS

2010 ◽  
Vol 82 (1) ◽  
pp. 31-43 ◽  
Author(s):  
TIEN-CHUNG HU ◽  
PING YAN CHEN ◽  
N. C. WEBER
Keyword(s):  
Law Of Large Numbers ◽  
Moving Average ◽  
Average Process ◽  
Moving Average Process ◽  
Strong Law ◽  
Rate Law ◽  
Large Numbers ◽  
Random Elements

AbstractThe conditions in the strong law of large numbers given by Li et al. [‘A strong law for B-valued arrays’, Proc. Amer. Math. Soc.123 (1995), 3205–3212] for B-valued arrays are relaxed. Further, the compact logarithm rate law and the bounded logarithm rate law are discussed for the moving average process based on an array of random elements.

Vector linear time series models

1976 ◽  
Vol 8 (2) ◽  
pp. 339-364 ◽  
Author(s):  
W. Dunsmuir ◽  
E. J. Hannan
Keyword(s):  
Time Series ◽  
Linear Models ◽  
Linear Time ◽  
Moving Average ◽  
Autoregressive Moving Average ◽  
Multiple Time ◽  
Strong Law ◽  
Large Numbers ◽  
Spectral Approximations ◽  
Vector Time Series

This paper presents proofs of the strong law of large numbers and the central limit theorem for estimators of the parameters in quite general finite-parameter linear models for vector time series. The estimators are derived from a Gaussian likelihood (although Gaussianity is not assumed) and certain spectral approximations to this. An important example of finite-parameter models for multiple time series is the class of autoregressive moving-average (ARMA) models and a general treatment is given for this case. This includes a discussion of the problems associated with identification in such models.

scholarly journals A Computer Program for Radiocarbon Age Calibration

Radiocarbon ◽  
1986 ◽  
Vol 28 (2B) ◽  
pp. 1022-1030 ◽  
Author(s):  
Minze Stuiver ◽  
Paula J Reimer
Keyword(s):  
Standard Deviation ◽  
Computer Program ◽  
Data Base ◽  
Calibration Curve ◽  
Radiocarbon Age ◽  
Calibration Curves

The calibration curves and tables given in this issue of RADIOCARBON form a data base ideally suited for a computerized operation. The program listed below converts a radiocarbon age and its age error os (one standard deviation) into calibrated ages (intercepts with the calibration curve), and ranges of calibrated ages that correspond to the age error. The standard deviation oC in the calibration curve is taken into account using (see Stuiver and Pearson, this issue, for details).

scholarly journals Corrigenda

1972 ◽  
Vol 25 (3) ◽  
pp. 337
Author(s):  
REB Munro
Keyword(s):  
Computer Program ◽  
Correction Factor ◽  
Zenith Angle ◽  
Order Correction ◽  
Radio Sources ◽  
First Order ◽  
First Order Correction

Observations at 408 MHz of radio sources from the 4C catalogue. By R. E. B. Munro "I. Declination range ?7� to ?3�." pp.263-91 "II. Declination range ?3� to 0�." pp. 617?30 Owing to an error in the computer program used to produce Table 4 of Part I and Table 1 of Part II, the quoted declination errors are generally too small. A first-order correction may be effected by multiplying the quoted errors by (secz)/(secd), where z is the zenith angle and d the declination. This correction factor leads to a slight overestimation (= 12%) for the stronger sources.

Sign in / Sign up

Export Citation Format

Share Document