Analyzing Collision,Grounding, and Sinking Accidents Occurring in the Black Sea Utilizing HFACS and Bayesian Networks

This study examines and analyzes marine accidents that have occurred over the past 20 years in the Black Sea. Geographic information system, human factor analysis and classification system (HFACS), and Bayesian network models are used to analyze the marine accidents. The most important feature distinguishing this study from other studies is that this is the first study to analyze accidents that have occurred across the whole Black Sea. Another important feature is the application of a new HFACS structure to reveal accident formation patterns. The results of this study indicate that accidents occurred in high concentrations in coastal regions of the Black Sea, especially in the Kerch Strait, Novorossiysk, Kilyos, Constanta, Riva, and Batumi regions. The formation of grounding and sinking accidents has been found to be similar in nature; the use of inland and old vessels has been highlighted as important factors in sinking and grounding incidents. However, the sequence of events leading to collision-contact accidents differs from the sequence of events resulting in grounding and sinking accidents. This study aims to provide information to the maritime industry regarding the occurrence of maritime incidents in the Black Sea, in order to assist with reduction and prevention of the marine accidents.     

The development of infants’ sensitivity to native versus non-native rhythm

Speech rhythm is considered one of the first windows into the native language, and the taxonomy of rhythm classes is commonly used to explain early language discrimination. Relying on formal rhythm classification is problematic for two reasons. First, it is not known to which extent infants’ sensitivity to language variation is attributable to rhythm alone, and second, it is not known how infants discriminate languages not classified in any of the putative rhythm classes. Employing a central-fixation preference paradigm with natural stimuli, this study tested whether infants differentially attend to native versus nonnative varieties that differ only in temporal rhythm cues, and both of which are rhythmically unclassified. An analysis of total looking time did not detect any rhythm preferences at any age. First-look duration, arguably more closely reflecting infants’ underlying perceptual sensitivities, indicated age-specific preferences for native versus non-native rhythm: 4-month-olds seemed to prefer the native-, and 6-month-olds the non-native language-variety. These findings suggest that infants indeed acquire native rhythm cues rather early, by the 4th month, supporting the theory that rhythm can bootstrap further language development. Our data on infants’ processing of rhythmically unclassified languages suggest that formal rhythm classification does not determine infants’ ability to discriminate language varieties.     

Young care leavers' expectations of their future: A question of time horizon

This paper investigates young care leavers' expectations of their future after discharge from care. The results are based on qualitative longitudinal data where 16‐ to 21‐year‐old care leavers (n = 15) were interviewed twice, first when still in care but planning for their discharge (T1) and the second time 6–9 months later (T2). The analysis using a general inductive approach showed that their expectations were dependent on the time horizon and that there was an obvious difference between the young informants' short‐ and long‐term expectations. Their short‐term expectations consisted of worries connected to their approaching discharge (at T1) and how to cope with challenges of everyday life after discharge from care (at T2). These results seem to echo negative outcomes shown in previous quantitative research. However, the informants' long‐term expectations provide a different picture, being mainly positive in both interviews (T1 and T2). The results are discussed from a life course perspective, where the informants' visions of their future are framed and understood in terms of the different stages of their transition process.     

Survival functions for the frailty models based on the discrete compound Poisson process

Frailty models are often used to model heterogeneity in survival analysis. The distribution of the frailty is generally assumed to be continuous. In some circumstances, it is appropriate to consider discrete frailty distributions. Having zero frailty can be interpreted as being immune, and population heterogeneity may be analysed using discrete frailty models. In this paper, survival functions are derived for the frailty models based on the discrete compound Poisson process. Maximum likelihood estimation procedures for the parameters are studied. We examine the fit of the models to earthquake and the traffic accidents’ data sets from Turkey.     

Monte Carlo Simulation Study of Biased Estimators in the Linear Regression Models with Correlated or Heteroscedastic Errors

In this study, the performance of the estimators proposed in the presence of multicollinearity in the linear regression model with heteroscedastic or correlated or both error terms is investigated under the matrix mean square error criterion. Structures of the autocorrelated error terms are given and a Monte Carlo simulation study is conducted to examine the relative efficiency of the estimators against each other.     

An alternative algorithm of the empirical likelihood estimation for the parameter of a linear regression model

ABSTRACT

Empirical likelihood (EL) is a nonparametric method based on observations. EL method is defined as a constrained optimization problem. The solution of this constrained optimization problem is carried on using duality approach. In this study, we propose an alternative algorithm to solve this constrained optimization problem. The new algorithm is based on a newton-type algorithm for Lagrange multipliers for the constrained optimization problem. We provide a simulation study and a real data example to compare the performance of the proposed algorithm with the classical algorithm. Simulation and the real data results show that the performance of the proposed algorithm is comparable with the performance of the existing algorithm in terms of efficiencies and cpu-times.     

A Prediction-Oriented Criterion for Choosing the Biasing Parameter in Liu Estimation

Distribution-free tests have been proposed in the literature for comparing the hazard rates of two probability distributions when the available samples are complete. In this article, we generalize the test of Kochar (1981 Kochar , S. C. ( 1981 ). A new distribution-free test for the equality of two failure rates . Biometrika 68 : 423 – 426 .[Crossref], [Web of Science ®] , [Google Scholar]) to the case when the available sample is Type-II censored, and then examine its power properties.     

Comment on Ridge Estimation to the Restricted Linear Model

In this note, we show that the estimator and the following results given by Zhong and Yang (2007 Zhong , Z. , Yang , H. ( 2007 ). Ridge estimation to the restricted linear model . Commun. Statist. Theor. Meth. 36 : 2099 – 2115 .[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]) are the same with that of Groß (2003 Groß , J. ( 2003 ). Restricted ridge estimation . Statist. Probab. Lett. 65 : 57 – 64 .[Crossref], [Web of Science ®] , [Google Scholar]).     

Combining Unbiased Ridge and Principal Component Regression Estimators

In the presence of multicollinearity problem, ordinary least squares (OLS) estimation is inadequate. To circumvent this problem, two well-known estimation procedures often suggested are the unbiased ridge regression (URR) estimator given by Crouse et al. (1995 Crouse , R. , Jin , C. , Hanumara , R. ( 1995 ). Unbiased ridge estimation with prior information and ridge trace . Commun. Statist. Theor. Meth. 24 : 2341 – 2354 .[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]) and the (r, k) class estimator given by Baye and Parker (1984 Baye , M. , Parker , D. ( 1984 ). Combining ridge and principal component regression: a money demand illustration . Commun. Statist. Theor. Meth. 13 : 197 – 205 .[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]). In this article, we proposed a new class of estimators, namely modified (r, k) class ridge regression (MCRR) which includes the OLS, the URR, the (r, k) class, and the principal components regression (PCR) estimators. It is based on a criterion that combines the ideas underlying the URR and the PCR estimators. The standard properties of this new class estimator have been investigated and a numerical illustration is done. The conditions under which the MCRR estimator is better than the other two estimators have been investigated.     

On Testing Changes in Autoregressive Parameters of a VAR Model

The article deals with the problem of testing a change in autoregressive matrices of the p-th order vector autoregressive process, VAR(p). The proposed test statistics are based on the likelihood ratio concept and are studied under the null hypothesis of no change in parameters. Their asymptotic behavior is derived under minimal moment assumptions in both cases where the time point of possible change is known a priori and is undefined. The Gumbel-type approximation of the test statistic is also developed, which previous papers on VAR(p) models do not cover.