Panel data, also known as longitudinal data, are composed of repeated measurements taken from the same subject over different time points. Although it is generally used in time series applications, forecasting can also be used in panel data due to its time dimension. However, there is limited number of studies in this area in the literature. In this thesis, forecasting is studied for panel data with binary response because of its increasing importance and increasing fundamental roles. A simulation study is held to compare the efficiency of different methods and to find the one that gives the optimal forecast values. In this simulation, 21 different methods, including na&iuml / ve and complex ones, are used by the help of R software. It is concluded that transition models and random effects models with no lag of response can be chosen for getting the most accurate forecasts, especially for the first two years of forecasting.

Longitudinal data arise when subjects are followed over time. This type of data is typically dependent, due to including repeated observations and this type of dependence is termed as within-subject dependence. Often the scientific interest is on multiple longitudinal measurements which introduce two additional types of associations, between-response and cross-response temporal dependencies. Only the statistical methods which take these association structures might yield reliable and valid statistical inferences. Although the methods for univariate longitudinal data have been mostly studied, multivariate longitudinal data still needs more work. In this thesis, although we mainly focus on multivariate longitudinal binary data models, we also consider other types of response families when necessary. We extend a work on multivariate marginal models, namely multivariate marginal models with response specific parameters (MMM1), and propose multivariate marginal models with shared regression parameters (MMM2). Both of these models are generalized estimating equation (GEE) based, and are valid for several response families such as Binomial, Gaussian, Poisson, and Gamma. Two different R packages, mmm and mmm2 are proposed to fit them, respectively. We further develop a marginalized multilevel model, namely probit normal marginalized transition random effects models (PNMTREM) for multivariate longitudinal binary response. By this model, implicit function theorem is introduced to explicitly link the levels of marginalized multilevel models with transition structures for the first time. An R package, bf pnmtrem is proposed to fit the model. PNMTREM is applied to data collected through Iowa Youth and Families Project (IYFP). Five different models, including univariate and multivariate ones, are considered to forecast multivariate longitudinal binary data. A comparative simulation study, which includes a model-independent data simulation process, is considered for this purpose. Forecasting independent variables are taken into account as well. To assess the forecasts, several accuracy measures, such as expected proportion of correct prediction (ePCP), area under the receiver operating characteristic (AUROC) curve, mean absolute scaled error (MASE) are considered. Mother&#039 / s Stress and Children&#039 / s Morbidity (MSCM) data are used to illustrate this comparison in real life. Results show that marginalized models yield better forecasting results compared to marginal models. Simulation results are in agreement with these results as well.

Nigeria is one of the countries most affected by the HIV/AIDS pandemic, third only to India and South Africa. With about 10% of the global HIV/AIDS cases estimated to be in the country, the public health and socio-economic implications are enormous. This thesis has two broad aims: the first is to develop statistical models which adequately describe the spatial distribution of the Nigerian HIV/AIDS epidemic and its associated ecological risk factors; the second, to develop models that could reconstruct the HIV incidence curve, obtain an estimate of the hidden HIV/AIDS population and a short term projection for AIDS incidence and a measure of precision of the estimates. To achieve these objectives, we first examined data from various sources and selected three sets of data based on national coverage and minimal reporting delay. The data sets are the outcome of the National HIV/AIDS Sentinel Surveillance Survey conducted in 1999, 2001, 2003 and 2005 by the Federal Ministry of Health; the outcome of the survey of 1057 health and laboratory facilities conducted by the Nigerian Institute of Medical Research in 2000; and case by case HIV screening data collected from an HIV/AIDS centre of excellence. A thorough review of methods used by WHO/UNAIDS to produce estimates of the Nigerian HIV/AIDS scenario was carried out. The Estimation and Projection Package (EPP) currently being used for modelling the epidemic partitions the population into at-risk, not-at-risk and infected sub-populations. It also requires some parameter input representing the force of infection and behaviour or high risk adjustment parameter. It may be difficult to precisely ascertain the size of these population groups and parameters in countries as large and diverse as Nigeria. Also, the accuracy of vital rates used in the EPP and Spectrum program is doubtful. Literature on ordinary back-calculation, nonparametric back-calculation, and modified back-calculation methods was reviewed in detail. Also, an indepth review of disease mapping techniques including multilevel models and geostatistical methods was conducted. The existence of spatial clusters was investigated using cluster analysis and some measure of spatial autocorrelation (Moran I and Geary c coefficients, semivariogram and kriging) applied to the National HIV/AIDS Surveillance data. Results revealed the existence of spatial clusters with significant positive spatial autocorrelation coefficients that tended to get stronger as the epidemic developed through time. GAM and local regression fit on the data revealed spatial trends on the north-south and east - west axis. Analysis of hierarchical, spatial and ecological factor effects on the geographical variation of HIV prevalence using variance component and spatial multilevel models was performed using restricted maximum likelihood implemented in R and empirical and full Bayesian methods in WinBUGS. Results confirmed significant spatial effects and some ecological factors were significant in explaining the variation. Also, variation due to various levels of aggregation was prominent. Estimates of cumulative HIV infection in Nigeria were obtained from both parametric and nonparametric back-calculation methods. Step and spline functions were assumed for the HIV infection curve in the parametric case. Parameter estimates obtained using 3-step and 4-step models were similar but the standard errors of these parameters were higher in the 4-step model. Estimates obtained using linear, quadratic, cubic and natural splines differed and also depended on the number and positions of the knots. Cumulative HIV infection estimates obtained using the step function models were comparable with those obtained using nonparametric back-calculation methods. Estimates from nonparametric back-calculation were obtained using the EMS algorithm. The modified nonparametric back-calculation method makes use of HIV data instead of the AIDS incidence data that are used in parametric and ordinary nonparametric back-calculation methods. In this approach, the hazard of undergoing HIV test is different for routine and symptom-related tests. The constant hazard of routine testing and the proportionality coefficient of symptom-related tests were estimated from the data and incorporated into the HIV induction distribution function. Estimates of HIV prevalence differ widely (about three times higher) from those obtained using parametric and ordinary nonparametric back-calculation methods. Nonparametric bootstrap procedure was used to obtain point-wise confidence interval and the uncertainty in estimating or predicting precisely the most recent incidence of AIDS or HIV infection was noticeable in the models but greater when AIDS data was used in the back-projection model. Analysis of case by case HIV screening data indicate that of 33349 patients who attended the HIV laboratory of a centre of excellence for the treatment of HIV/AIDS between October 2000 and August 2006, 7646 (23%) were HIV positive with females constituting about 61% of the positive cases. The bulk of infection was found in patients aged 15-49 years, about 86 percent of infected females and 78 percent of males were in this age group. Attendance at the laboratory and the proportion of HIV positive tests witnessed a remarkable increase when screening became free of charge. Logistic regression analysis indicated a 3-way interaction between time period, age and sex. Removing the effect of time by stratifying by time period left 2-way interactions between age and sex. A Correction factor for underreporting was ascertained by studying attendance at the laboratory facility over two time periods defined by the cost of HIV screening. Estimates of HIV prevalence obtained from corrected data using the modified nonparametric back-calculation are comparable with UN estimates obtained by a different method. The Nigerian HIV/AIDS pandemic is made up of multiple epidemics spatially located in different parts of the country with most of them having the potential of being sustained into the future given information on some risk factors. It is hoped that the findings of this research will be a ready tool in the hands of policy makers in the formulation of policy and design of programs to combat the epidemic in the country. Access to data on HIV/AIDS are highly restricted in the country and this hampers more in-depth modelling of the epidemic. Subject to data availability, we recommend that further work be done on the construction of stratification models based on sex, age and the geopolitical zones in order to estimate the infection intensity in each of the population groups. Uncertainties surrounding assumptions of infection intensity and incubation distribution can be minimized using Bayesian methods in back-projection.

published_or_final_version / Architecture / Master / Master of Architecture

Study object. The state managed forests of Middle Lithuanian plain landscape geographical region (Kedainiai, Birzai, Joniskis, Kaunas, Pakruojis and Panevezys forest enteprises) and Nemunas bottom-land plain geographical region (Tauragė, Jurbarkas, Sakiai, Kazlu Ruda and Marijampole forest enterprises). Study aim. To evaluate the forest yield capacity of nature and administrative units. Methodology. The forest yield capacity is evaluated by calculating the mean volume per hectare and by assessing the yield capacity using the methodology of S. G. Sinicin. Results. There was made a comparison of forest yield capacity between two geographical landscape regions (Middle Lithuanian plain and Nemunas bottom-land plain). It was assessed that the mean volume per hectare in Middle Lithuanian plain is 5,2% and the forest yield capacity (according to S.G. Sinicin) is 3,8 % higher than in Nemunas bottom-land plain geographical region. Further on it was made comparison between the mean volume and forest yield capacity per hectare in forest enterprises in these two geographical regions. It was assessed that the highest mean volumes have Kazlų Rūda, Šakiai and Marijampolė forest enterprises. The highest yield capacities (according to S.G. Sinicin) have Taurage, Jurbarkas and Šakiai forest enterprises. Key words: Middle Lithuanian plain landscape geographical region, Nemunas bottom-land plain landscape geographical region), forest yield capacity, mean volume per hectare. s 1 ha.

Rashi, an eleventh century Bible commentator who lived in France, is the most influential Jewish exegete of all time. The popularity of his Pentateuch commentary has resulted in many extant manuscripts and printed editions, and the effect of scribal activity involved in the work's large circulation has led to extensive textual variants. Moreover, the earliest extant dated manuscript of the commentary was copied 130 years after Rashi's death. This extended length of time facilitated the introduction of countless changes into the work that, over time, have become virtually undetectable. / One key to uncovering the most authentic version of Rashi's commentary is to examine texts written as close to his lifetime as possible. Since neither Rashi's own copy of his commentary nor any reasonable alternative has been discovered, the Pentateuch commentaries of his immediate successors, the Franco-German writers known as the Tosafot, provide the closest possible substitute. For the most part, the writings of these twelfth- and thirteenth-century relatives and students of Rashi consisted of glosses, explanations and criticisms of his work. / This study compares citations of Rashi in over fifty manuscripts of Tosafot commentaries with texts of Rashi published in both early and modern printings and in over thirty manuscripts of his commentary. It suggests that the text of Rashi utilized by the Tosafot was significantly different from the printed versions. Examples show that portions of the printed interpretations attributed to Rashi are actually explanations and criticisms offered by the Tosafot that, through various processes, were attributed to the master himself. Awareness of this helps establish a reliable witness to the text of Rashi's Pentateuch commentary, and it suggests that the Tosafot must be an important component of any future efforts to establish a scientific edition of it.

Approved for public release; distribution is unlimited / On January 12, 2010, a 7.0 magnitude earthquake occurred 16 miles west of the Haitian capital of Port-au-Prince. The earthquake and ensuing destruction killed as many as 300,000 persons and displaced as many as 1.5 million more creating a humanitarian crisis and economic disaster of enormous scale. As the earthquake was in close proximity to the U.S. mainland, it was determined that three U.S. agencies would take leading roles: USAID would coordinate and lead the relief effort, the U.S. State Department would handle diplomatic issues and the Department of Defense (DoD) would take the lead on logistics and security issues. One social networking tool used by the DoD and relief organizations to share information and coordinate relief efforts was the All Partners Access Network (APAN). Communications between the various agencies were recorded and include chat logs, blogs and e-mails. A content analysis was conducted to develop insight into the way relief workers used APAN when responding during the Haiti humanitarian assistance / disaster relief (HA/DR) operation. Coding and analyzing the communication data collected during the relief effort provided insight into how individuals and organizations used APAN, a social networking tool, to collaborate during the disaster. Suggestions for improving APAN are discussed.

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Acrylic bone cements are one of the most important biomaterials used in orthopaedic surgery and dental applications to fill the cavities or provide mechanical interlock between prosthesis and the bone. Their biocompatibility can be increased by addition of different materials into the formulation, such as hydroxyapatite. Besides all the advantages, bone cements have several drawbacks including tissue necrosis, chemical necrosis, shrinkage of the cement and aseptic loosening. Therefore painstaking research and study are carried out on development of new formulations to improve mechanical and thermal properties as well as biocompatibilities. In this study, bone cements with different compositions were prepared and new formulations were examined to improve mechanical properties and to reduce maximum curing temperature. It was observed that addition of hydroxyapatite, while keeping polymer-to-monomer ratio constant at 2.0, decreased curing temperature and increased compressive strength about 11% (Group-C) when hydroxyapatite addition was 12%. Further addition of hydroxyapatite destroyed homogeneity of the cement dough and made it difficult to handle. The composition which contains 8% hydroxyapatite was chosen as the optimum composition in respect of mechanical properties with 102.62&deg / C curing temperature. In order to decrease the curing temperature ammonium nitrate this gives endothermic reactions with water, was added into the formulations. Addition of 0.5 g NH4NO3 decreased curing temperature from 94&deg / C to 79.3&deg / C while compressive strength kept in acceptable range with 95.99 MPa. Experiments demonstrated that the proposed formulation is acceptable for workability, homogeneity, mechanical strength and thermal properties. Further studies especially on curing temperature and biocompatibility should be achieved.

In this study, the most prominent goodness-of-fit tests for censored samples are reviewed. Power properties of goodness-of-fit statistics of the null hypothesis that a sample which is censored from right, left and both right and left which comes from uniform, normal and exponential distributions are investigated. Then, by a similar argument extreme value, student t with 6 degrees of freedom and generalized logistic distributions are discussed in detail through a comprehensive simulation study. A variety of real life applications are given. Suitable test statistics for testing the above distributions for censored samples are also suggested in the conclusion.