D. A. Dickey

North Carolina State University | NCSU · Department of Statistics

Bioenergy is one of the most considered alternatives to fossil fuels. Short-rotation woody crops (SRWCs) as bioenergy sources are capable of alleviating energy constraints and sequestering atmospheric CO2. However, studies investigating soil carbon (C) dynamics at SWRC plantations are scarce. We studied American sycamore (Platanus occidentalis) as...

Potable source‐water reservoirs are the main water supplies in many urbanizing regions, yet their long‐term responses to cultural eutrophication are poorly documented in comparison to natural lakes, creating major management uncertainties. Here, long‐term discrete data (June 2006–June 2018) for classical eutrophication water quality indicators, con...

USDA-Max × Soja Core Set-1 (USDA-MxS-CS1-1 to USDA-MxS-CS1-17 [Reg. No. GP-417 to GP-433, PI 689053 to PI 689069]) is a group of 17 interspecific breeding lines developed from the hybridization of lodging-resistant soybean cultivar N7103 [Glycine max (L.) Merr.] with wild soybean plant introduction PI 366122 [G. soja Siebold & Zucc.]. These materia...

Measurements of Ra-226 activity from eight HPGe gamma ray detectors at the NC State University PULSTAR Reactor were analyzed for evidence of periodic variations, with particular attention to annual variations. All measurements were made using the same reference source, and data sets were of varying length taken over the time period from September 1...

Poster Presentation

Statistical models for the seasonal prediction of hurricane strikes on the Eastern Seaboard of the United States (ESUS) are developed with the application of the statistical software (SAS) generalized linear model (GENMOD) to perform a Poisson regression linked by a logarithmic function. Preseason climatic/oceanic signals of the El Nino South Oscil...

A method of manufacturing a fluidic structure is disclosed. A cavity that defines a shape of an element of the fluidic structure within a material is formed. The cavity is filled with liquid metal. The cavity is sealed. The fluidic structure behaves as an antenna. A fluidic antenna includes a material that defines a shape of the fluidic antenna by...

The statistically significant inverse relationship is examined between North American snow cover extent during January and North Atlantic hurricane activity during the following hurricane season. To better quantify this relationship the long‐term trend and ENSO years were removed from the data. The lightest January snow‐cover years (LSY) show sharp...

a b s t r a c t This paper presents a study for identifying damage locations in an idealized steel bridge girder using the ambient vibration measurements. A sensitive damage feature is proposed in the context of statistical pattern recognition to address the damage detection problem. The study utilizes an experimental program that consists of a two...

Dickey and Zhang (2010) developed a central limit theorem for seasonal unit root tests based on the studentized coeficient in the regression of Yt - Yt-d on Yt-d when the seasonal period d gets large. They give an easily computable order d-1/2 bias adjustment whose inclusion brings the statistic’s distribution quite close to its N(0, 1) limit for d...

Organic soybean [Glycine Max (L.) Merr.] producers rely on a variety of tactics for weed management. The use of soybean cultivars with enhanced ability to compete with weeds may increase weed control. Our objective was to identify genetic traits that may enhance soybean's competitive ability to suppress weeds. Experimental design was a split-split...

The trends and intrinsic frequencies in the time series of the number of Tropical Cyclones (TCs), hurricanes and typhoons, and Categories 4 and 5 hurricanes and typhoons in the Atlantic and Pacific Ocean domains, and the yearly integral of hurricane wind energy, represented by the Power Density Index (PDI), in the Atlantic and Eastern North Pacific...

A study of factors affecting the number of visitors to Hawaii during the period 1993–2007 prompted by an observed waning of the U. S. mainland to Hawaii visitor market was conducted. Both time series and cross section analyses revealed that Log Gross State Product, Log Chained Airfare and Log Distance to Orlando, Florida were the most important pre...

Atmospheric and oceanic climate factors and conditions play a crucial role in modulating seasonal/annual tropical cyclone activity in the North Atlantic Ocean Basin. In the following, correlations between North Atlantic tropical cyclone activity including frequency of occurrence and pathways are explored, with special emphasis on hurricanes. The va...

a b s t r a c t Seasonal differencing is often applied when reporting, for example, monthly sales. New car sales are often reported to be up or down from the same period last year. Tests for the need to seasonally difference data are seasonal unit root tests. We modify the tests of Dickey, Hasza, and Fuller (1984) to investigate results for less ty...

This paper compares two different approaches to identify damage locations in structural members subjected to ambient vibrations. The concept is demonstrated using a simply supported two span steel beam. An electro-hydraulic actuator was used to simulate ambient loading by applying random loads. The vibration time histories were collected for the un...

Coastal sea level rise and fall are governed deterministically by the astronomical tides and stochastically by a host of other factors. Coastal storms occur stochastically. True rates of temporal variability and trends of both sea level variability and storm occurrence, over local to regional scales are not presently identically known, in spite of...

Ammonia (NH3) fluxes from waste treatment lagoons and barns at two conventional swine farms in eastern North Carolina were measured. The waste treatment lagoon data were analyzed to elucidate the temporal (seasonal and diurnal) variability and to derive regression relationships between NH3 flux and lagoon temperature, pH and ammonium content of the...

The need for developing environmentally superior and sustainable solutions for managing the animal waste at commercial swine farms in eastern North Carolina has been recognized in recent years. Program OPEN (Odor, Pathogens, and Emissions of Nitrogen), funded by the North Carolina State University Animal and Poultry Waste Management Center (APWMC),...

The animal husbandry industry is a major emitter of ammonia (NH 3), which is a precursor of fine particulate matter (PM 2.5)—arguably, the number-one environment-related public health threat facing the nation. The industry is also a major emitter of methane (CH 4), which is an important greenhouse gas (GHG). We present an integrated process model o...

This study investigates the frequency of occurrence of tropical cyclones and land-falling hurricanes in the North Atlantic and the Gulf of Mexico over the five telescoping periods of 1851-2006, 1888-2006, 1900-2006, 1950-2006 and 1970-2006. An effort is made to assess the intrinsic modes of variability and trends buried in the data but also to iden...

The national build-up of “coastal ocean observing systems” (COOSs) to establish the coastal observing component of the national component of the Integrated Ocean Observing System (IOOS) network must be well organized and must acknowledge, understand and address the needs of the principal clients, the federal, and in some cases state as well, agenci...

Infectious salmon anemia (ISA) has caused severe morbidity and mortality in farmed Atlantic salmon in North America, Norway, Scotland and the Faroe Islands. The Quoddy region of Maine, United States of America (USA), and New Brunswick (NB), Canada is characterized by extensive tidal mixing and close proximity between farms. This region is also pron...

The marine atmosphere, coastal ocean, estuary, harbor and river water systems constitute a physically coupled system. While these systems have always been heavily impacted by coastal storms, increases in population density, infrastructure, and personal and business merchandise have exacerbated the economic and personal impacts of these events over...

A case is made that the national process of special appropriations monies to establish the coastal observing component of the integrated ocean observing system (IOOS) network is not well organized and without substantive value, given the way that it has been orchestrated. Alternatively, a case is made that the special appropriations monies could an...

A temporal analysis of the number and duration of exceedences of high- and low-flow thresholds was conducted to determine the number of years required to detect a level shift using data from Virginia, North Carolina, and South Carolina. Two methods were used—ordinary least squares assuming a known error variance and generalized least squares withou...

Sea level variability along the eastern seaboard of the US is studied using continuous time series of data collected at seven NOAA NOS NWLON stations. Sea level variability has many modes of variability and from year to year the sea level may rise or fall. It is observed that the winter season brings about a contraction of the North Atlantic ocean...

The likelihood function of a seasonal model, Y_t = ρY_t - d + e_t as implemented in computer algorithms under the assumption of stationary initial conditions is a function of ρ which is zero at the point ρ = 1. It is a smooth function for ρ in the above seasonal model with a well-defined maximum regardless of the data-generating mechanism. Gonzalez...

The North Carolina State University Coastal and Estuary Marine & Environmental Prediction System (CEMEPS) is a coupled system of mathematical models. CEMEPS contains a suite of interactively linked atmospheric, oceanic, estuary and river model components. The model architecture couples mesoscale atmospheric models or event models such as hurricanes...

A flood potential damage risk index based on complete physics was discussed using the state of the science numerical model. A need for developing such a scale arised because of the unavailability and unreliability of the existing flood forecast information scales. The physical basis for such a scale was established and the mathematical architecture...

In this paper, we suggest alternative test statistics for testing the unit root null hypothesis in the presence of a trend-break. Our new test procedure which we call the "bisection" method is based on the idea of subgrouping. The idea here is to split the data in half and look at the minimum of the resulting two unit root test statistics. Avoiding...

The previous chapter developed the regression results involving linear functions of the dependent variable, \( \hat \beta\), Ŷ, and e. All were shown to be normally distributed random variables if Y was normally distributed.

Chapter 1 reviewed simple linear regression in algebraic notation and showed that the notation for models involving several variables is very cumberome. This chapter introduces matrix notation and all matrix operations that are used in this text. Matrix algebra greatly simplifies the presentation of regression and is used throughout the text. Secti...

To this point we have assumed that the relationship between the dependen variable Y and any independent variable X can be represented with a straight line. This clearly is inadequate in many cases. This chapter introduces the extensively used polynomial and trigonometric regression response models to characterize curvilinear relationships. Such mod...

On-farm data collection consists of a dynamic interaction between the interviewer and respondent via a questionnaire. Non-sampling errors introduced by these sources during the measurement process often account for a greater proportion of the total survey error than sampling error alone. A two pronged approach was used to evaluate non-sampling erro...

The United States Department of Agriculture's (USDA) National Animal Health Monitoring System (NAHMS) National Swine Survey (NSS), implemented in 1990, represents the first national effort to collect on-farm data using a statistically valid method. The purpose of the North Carolina Swine Survey (NCSS) was to evaluate the reliability of the NSS by a...

We investigate a test for unit roots in autoregressive time series based on maximization of the unconditional likelihood. This is the likelihood function appropriate for stationary time series. While this function is the true likelihood only under the stationary alternative, it can nevertheless be maximized for any data including data from a unit r...

Mammary internal and surface temperatures and milk temperature were correlated using five lactating goats. Internal mammary temperature was estimated using temperature-sensitive transmitters placed deep within the parenchyma of each mammary half. External mammary temperature was estimated using infrared thermography of four mammary skin sites: T1,...

Mammary internal and surface temperatures and milk temperature were correlated using five lactating goats. Internal mammary temperature was estimated using temperature-sensitive transmitters placed deep within the parenchyma of each mammary half. External mammary temperature was estimated using infrared thermography of four mammary skin sites: T1,...

The characteristic equation of a multiple autoregressive time series involves the eigenvalues of a matrix equation which determine if the series is stationary. Suppose one eigenvalue is 1 and the rest are less than 1 in magnitude. We show that ordinary least squares may be used to estimate the matrices involved and that the largest estimated eigenv...

Regression estimators of coefficients in seasonal autoregressive models are described. The percentiles of the distributions for time series that have unit roots at the seasonal lag are computed by Monte Carlo integration for finite samples and by analytic techniques and Monte Carlo integration for the limit case. The tabled distributions may be use...

The new method specifying the Fossomatic-90 differs from the official method, 46.105-46.109, in that the modified instrument includes a halogen lamp; a semiconductor photoelectric detector; a less expensive, bench-top cabinet; manual injection of a larger sample, and a reduced capacity. The new instrument was compared with 2 optical somatic cell co...

Pulsation rate, pulsation ratio, and vacuum-decrease time were regulated independently and applied in various combinations to individual quarters of four experimental cows. A static pulsation ratio was used in assigning treatments and was measured on pulsation curves at 20 kPa. This was the vacuum at which liner walls parted during graduated pressu...

Let n observations Y 1, Y 2, ···, Y n be generated by the model Y t = pY t−1 + e t , where Y 0 is a fixed constant and {e t } t-1 n is a sequence of independent normal random variables with mean 0 and variance σ2. Properties of the regression estimator of p are obtained under the assumption that p = ±1. Representations for the limit distributions o...

UnM cat. no.: 7701022. Thesis (Ph. D.)--Iowa State University, 1976. Includes bibliographical references (leaves 123-125). Microfilm. s

Experiences in teaching applied data mining techniques to university students already familiar with some statistical principles are reviewed. Additions to the standard fare of quick automated analyses of large data sets are emphasized. These examples link data mining techniques to the more classic statistical methods. SAS ® procedures from SAS/STAT...

Techniques for which the 2003 Economics Nobel Prize was awarded are illustrated with examples. These are cointegration and autoregressive conditionally heteroscedastic models. For this second topic, an introductory example without the heteroscedasticity leads into the more complex scenario.