ON EXTENSIONS OF PROBABILISTIC PROFIT BUDGETS

Previous work on probabilistic profit budgets has dealt with the construction of probability intervals for the items in the planning and control statements (e.g., direct costs, marginal contributions, profits, etc.). This paper expands that work by demonstrating the potential benefits for managerial accounting in constructing confidence limits for the mean, the standard deviation, and the coefficient of variation. The adequacy of the confidence interval for any account balance depends on the credibility of the sample standard deviation, s, as an estimate of the population standard deviation, σ. The confidence interval of the standard deviation assesses, in a sense, the precision of the point estimate, s. Furthermore, it takes on a meaning similar to risk measures discussed in the finance literature. Given confidence intervals for the mean and standard deviation, one can construct corresponding bands for the coefficient of variation. These bands give insight into the goodness of the accounting system and the stability of the budgetary model.     

Effects of park size,peri-urban forest spillover,and environmental filtering on diversity,structure, and morphology of ant assemblages in urban park

Urban Ecosystems - Urban parks are likely the last green areas to preserve fauna diversity in urban ecosystems. We predicted that 1) species richness and ant diversity would increase with...     

Testing for monotonic trend in time series based on resampling methods

In this paper, we propose several tests for monotonic trend based on the Brillinger's test statistic (1989, Biometrika, 76, 23–30). When there are highly correlated residuals or short record lengths, Brillinger's test procedure tends to have significance level much higher than the nominal level. It is found that this could be related to the discrepancy between the empirical distribution of the test statistic and the asymptotic normal distribution. Hence, in this paper, we propose three bootstrap-based procedures based on the Brillinger's test statistic to test for monotonic trend. The performance of the proposed test procedures is evaluated through an extensive Monte Carlo simulation study, and is compared to other trend test procedures in the literature. It is shown that the proposed bootstrap-based Brillinger test procedures can well control the significance levels and provide satisfactory power performance in testing the monotonic trend under different scenarios.     

The family exclusion order as a harm-minimisation measure for casino gambling: the case of Singapore

Singapore is one of the first jurisdictions in the world that has implemented a harm minimization model based on third party exclusion known as the Family Exclusion Order (FEO). Unlike other forms of third party exclusion practiced in other countries, family members in Singapore are able to apply for FEOs to prevent a gambler from entering the casinos, if the family has experienced harm caused by his/her gambling. In this study, 105 applicants for the FEO were sampled from all successful FEOs granted within a five-year period. Using a qualitative approach, this study attempts to illuminate the intricate issues experienced by family members that provided the impetus for them to apply for the FEO. While the extant literature posits self-exclusion as a superior tool of restraint as it involves the gambler’s personal motivation to curb gambling, this paper reports initial evidence of benefits resulting from family-imposed restraints from the perspective of family members. In particular, positive ratings of the FEO stemmed from a sense of relief experienced by mother and wife applicants. Possible reasons behind these positive outcomes are explicated using intrinsic motivation theory, with sensitivity to gender relations within the family.     

Naloxone administration for suspected opioid overdose: An expanded scope of practice by a basic life support collegiate-based emergency medical services agency

Opioid abuse is a growing and significant public health concern in the United States. Naloxone is an opioid antagonist that can rapidly reverse the respiratory depression associated with opioid toxicity. Georgetown University's collegiate-based emergency medical services (EMS) agency recently adopted a protocol, allowing providers to administer intranasal naloxone for patients with suspected opioid overdose. While normally not within the scope of practice of basic life support prehospital agencies, the recognition of an increasing epidemic of opioid abuse has led many states, including the District of Columbia, to expand access to naloxone for prehospital providers of all levels of training. In particular, intranasal naloxone is a method of administering this medication that potentially avoids needlestick injuries among EMS providers. Universities with collegiate-based EMS agencies are well positioned to provide life-saving treatments for patients acutely ill from opioid overdose.     

Learning-based EM algorithm for normal-inverse Gaussian mixture model with application to extrasolar planets

Karlis and Santourian [14 D. Karlis and A. Santourian, Model-based clustering with non-elliptically contoured distribution, Stat. Comput. 19 (2009), pp. 73–83. doi: 10.1007/s11222-008-9072-0[Crossref], [Web of Science ®] , [Google Scholar]] proposed a model-based clustering algorithm, the expectation–maximization (EM) algorithm, to fit the mixture of multivariate normal-inverse Gaussian (NIG) distribution. However, the EM algorithm for the mixture of multivariate NIG requires a set of initial values to begin the iterative process, and the number of components has to be given a priori. In this paper, we present a learning-based EM algorithm: its aim is to overcome the aforementioned weaknesses of Karlis and Santourian's EM algorithm [14 D. Karlis and A. Santourian, Model-based clustering with non-elliptically contoured distribution, Stat. Comput. 19 (2009), pp. 73–83. doi: 10.1007/s11222-008-9072-0[Crossref], [Web of Science ®] , [Google Scholar]]. The proposed learning-based EM algorithm was first inspired by Yang et al. [24 M.-S. Yang, C.-Y. Lai, and C.-Y. Lin, A robust EM clustering algorithm for Gaussian mixture models, Pattern Recognit. 45 (2012), pp. 3950–3961. doi: 10.1016/j.patcog.2012.04.031[Crossref], [Web of Science ®] , [Google Scholar]]: the process of how they perform self-clustering was then simulated. Numerical experiments showed promising results compared to Karlis and Santourian's EM algorithm. Moreover, the methodology is applicable to the analysis of extrasolar planets. Our analysis provides an understanding of the clustering results in the ln?P?ln?M and ln?P?e spaces, where M is the planetary mass, P is the orbital period and e is orbital eccentricity. Our identified groups interpret two phenomena: (1) the characteristics of two clusters in ln?P?ln?M space might be related to the tidal and disc interactions (see [9 I.G. Jiang, W.H. Ip, and L.C. Yeh, On the fate of close-in extrasolar planets, Astrophys. J. 582 (2003), pp. 449–454. doi: 10.1086/344590[Crossref], [Web of Science ®] , [Google Scholar]]); and (2) there are two clusters in ln?P?e space.     

Optimal experimental plan for multi-level stress testing with Weibull regression under progressive Type-II extremal censoring

In the design of constant-stress life-testing experiments, the optimal allocation in a multi-level stress test with Type-I or Type-II censoring based on the Weibull regression model has been studied in the literature. Conventional Type-I and Type-II censoring schemes restrict our ability to observe extreme failures in the experiment and these extreme failures are important in the estimation of upper quantiles and understanding of the tail behaviors of the lifetime distribution. For this reason, we propose the use of progressive extremal censoring at each stress level, whereas the conventional Type-II censoring is a special case. The proposed experimental scheme allows some extreme failures to be observed. The maximum likelihood estimators of the model parameters, the Fisher information, and asymptotic variance–covariance matrices of the maximum likelihood estimates are derived. We consider the optimal experimental planning problem by looking at four different optimality criteria. To avoid the computational burden in searching for the optimal allocation, a simple search procedure is suggested. Optimal allocation of units for two- and four-stress-level situations is determined numerically. The asymptotic Fisher information matrix and the asymptotic optimal allocation problem are also studied and the results are compared with optimal allocations with specified sample sizes. Finally, conclusions and some practical recommendations are provided.     

Simulation of some multivariate distributions related to the Dirichlet distribution with application to Monte Carlo simulations

Simulation of multivariate distributions is important in many applications but remains computationally challenging in practice. In this article, we introduce three classes of multivariate distributions from which simulation can be conducted by means of their stochastic representations related to the Dirichlet random vector. More emphasis is made to simulation from the class of uniform distributions over a polyhedron, which is useful for solving some constrained optimization problems and ha`s many applications in sampling and Monte Carlo simulations. Numerical evidences show that, by utilizing state-of-the-art Dirichlet generation algorithms, the introduced methods become superior to other approaches in terms of computational efficiency.     

Newborns' Cries are Unique to Individuals (But Not to Language Environment)

Human neonates exhibit individually distinctive patterns of variation—sometimes called cry “signatures”—in the acoustics of their cries. For tests of group differences (e.g., age, health status, or ambient language differences), the uniqueness of cry sounds to individuals means that multiple cries from same infant cannot appropriately be treated as independent events for analysis. This approach violates the assumption of independence that underlies many statistical techniques and runs the risk of uncovering “significant” group effects that do not actually exist. Nonetheless, publications continue to appear in which multiple cries from the same infant have been treated as independent events for analysis. To demonstrate the perils, we have compared the cries of infants born into a Mandarin Chinese language environment with cries of infants born into an American English language environment. We show (1) that treating each cry sound as an independent event yields numerous “significant” group effects and (2) that these effects all but disappear when cries are treated appropriately, as “nested” within individual infants. The latter outcome is in keeping with prevailing models of neonatal cry production and casts doubt on the claim that neonates alter their cries to match features of the language spoken in their environment.     

Why do households rent while owning houses? Housing sub-tenure choice in South Korea

This study aims to analyze the effects of household characteristics on housing sub-tenure choice and understand the behavior of families who opt to rent while owning other homes in South Korea. Tenure status is subdivided according to the difference between consumption and investment demands for housing. It is found that that when families are faced with the choice of renting while owning another house, the probability that they will decide on this option increases up to the sixth income decile and then declines. Similarly, this probability increases until the tenant reaches age 50 and then decreases. Furthermore, the probability of a household choosing to rent while owning another home is greater if a member of the household is married with school-age children.