1,157 research outputs found
A Comparison of Methods for Forecasting Demand for Slow Moving Car Parts
No full textThis paper has a focus on non-stationary time series formed from small non-negative integer values which may contain many zeros and may be over-dispersed. It describes a study undertaken to compare various suitable adaptations of the simple exponential smoothing method of forecasting on a database of demand series for slow moving car parts. The methods considered include simple exponential smoothing with Poisson measurements, a finite sample version of simple exponential smoothing with negative binomial measurements, and the Croston method of forecasting. In the case of the Croston method, a maximum likelihood approach to estimating key quantities, such as the smoothing parameter, is proposed for the first time. The results from the study indicate that the Croston method does not forecast, on average, as well as the other two methods. It is also confirmed that a common fixed smoothing constant across all the car parts works better than maximum likelihood approaches.Count time series; forecasting; exponential smoothing; Poisson distribution; negative binomial distribution; Croston method.
The vector innovation structural time series framework: a simple approach to multivariate forecasting
No full textThe vector innovation structural time series framework is proposed as a way of modelling a set of related time series. Like all multi-series approaches, the aim is to exploit potential inter-series dependencies to improve the fit and forecasts. A key feature of the framework is that the series are decomposed into common components such as trend and seasonal effects. Equations that describe the evolution of these components through time are used as the sole way of representing the inter-temporal dependencies. The approach is illustrated on a bivariate data set comprising Australian exchange rates of the UK pound and US dollar. Its forecasting capacity is compared to other common single- and multi-series approaches in an experiment using time series from a large macroeconomic database.Vector innovation structural time series, state space model, multivariate time series, exponential smoothing, forecast comparison, vector autoregression.
Basketball Team (1909)
No full textMcCarrell, John C.; Weimer, John W.; Breitenreiter, Alcon; Bream, Herbert A.; Snyder, Edgar E.; Phillipy, Norman G.; Brumbaugh, R.T.; Kopp, Charles L.; Bell, Ralph E.; Mosser, Oliver D.; Yohn, Ernest H.Spectrum 1910, p. 186-
Characteristics of Self-Citation in Journal of Natural Rubber Research 1988-1997: a Ten-Year Bibliometric Study
No full textAnalyses the extent of journal self-citation and author self-citation in the research articles and short communications published in Journal of Natural Rubber Research during 1988 to 1997. Results show that 53% of articles contained journal self-citations; the rate of journal self-citations per article ranges between 1 to 12; a high percentage of authors (61.4%) contributing articles to the journal cited themselves; a tendency is noticed for authors affiliated to the institution publishing the journal to cite the journal; the highest self-citing author is A. D. Roberts
Lack of cerebral BMAA in human cerebral cortex
No full textBioaccumulation of -methylamino-L-alanine (BMAA) through Cyanobacteria-contaminated food or water supplies has been suggested as a possible contributor to Parkinson-dementia complex (PDC) among the indigenous Chamorro of Guam as well as Alzheimer disease (AD) worldwide, a speculation that has been widely commented on in news and editorial sections of premier scientific and medical journals, and that has led to product recalls and government-sponsored assessments of public health in Europe. However, quantification of BMAA to date has been based on indirect high performance liquid chromatography methods. Given the potential global health significance, we developed a stable-isotope dilution assay for BMAA to more rigorously test its proposed bioaccumulation in cerebral cortex.Peer reviewedfinal article publishe
A View of Damped Trend as Incorporating a Tracking Signal into a State Space Model
No full textDamped trend exponential smoothing has previously been established as an important forecasting method. Here, it is shown to have close links to simple exponential smoothing with a smoothed error tracking signal. A special case of damped trend exponential smoothing emerges from our analysis, one that is more parsimonious because it effectively relies on one less parameter. This special case is compared with its traditional counterpart in an application to the annual data from the M3 competition and is shown to be quite competitive.Exponential smoothing, monitoring forecasts, structural change, adjusting forecasts, state space models, damped trend
Beveridge-Nelson Decomposition with Markov Switching
No full textThis paper considers Beveridge-Nelson decomposition in a context where the permanent and transitory components both follow a Markov switching process. Our approach incorporates Markov switching into a single source of error state-space framework, allowing business cycle asymmetries and regime switches in the long run multiplier.Beveridge-Nelson decomposition, Markov switching, Single source of error state space models
Uintah High School Board of Control
No full textUintah High School board of control are seated around a table with principal Harold Lundell and teacher D. L. McConkie. Standing from left are, Dale Haws, Howard Manwaring, Mr. McConkie, Eldon Oaks and Mr. Lundell. Seated, unidentified, unidentified, Ralph Preece, Laura Millecam, unidentified, Melba Calder, Melvin Hodgkinson, June Bateman, Charles Taylor, Lluana Workman and Sam Snyder
Editorial Board
No full textEditor-in Chief Barry F. Smith Business Manager Todd A. Hammer Technical Editor Gregory C. Black Note and Comment Editor Sherry J. Matteucci Associate Editors Monte D. Beck Ralph P. Kirscher Clarke B. Rice Virginia Bryan Sumner Staff Glenn A. Driveness Timothy D. Geiszler Kenneth T. Jarvi Michael F. Lamb Robert J. Law Danial N. McLean Sharon M. Morrison Susan R. Sharrock Randall A. Snyder John B. Spooner Erik B. Thueson Faculty Advisor Ronald C. Wyse Law Review Secretary Corrine Kirsche
A SPECTRAL LINE SURVEY OF SELECTED 3 MM BANDS TOWARD SAGITTARIUS B2(N-LMH) USING THE NRAO 12 METER RADIO TELESCOPE AND THE BIMA ARRAY II. DATA ANALYSIS
No full text Current address:NASA Goddard Space Flight Center, Earth and Space Data Computing Division, Code 930, Greenbelt, MD 20771 D. N. Friedel, L. E. Snyder, B. E. Turner, and A. Remijan, International Symposium on Molecular Spectroscopy, Talk FA03 (2003) D. N. Friedel, L. E. Snyder, B. E. Turner, and A. Remijan, ApJ 600, 243 (2004)Author Institution: Department of Astronomy, University of Illinois; Department of Astronomy, National Radio Astronomy Observatory; Department of Astronomy, University of IllinoisWe have analyzed the data from our 3 mm spectral line survey of the high mass star forming region Sagittarius , covering 3.6 GHz of bandwidth, where we detected 218 lines (97 identified molecular transitions, one recombination line, and 120 unidentified lines). The analysis was done using rotation-temperature diagrams and amplitude distributions in the plane. These methods give insight into the rotation temperature and column density of each observed species as well as the distribution on the sky. From the distribution information we can infer potential formation mechanisms for these species as well as constrain possible identifications for the unidentified transitions
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