Decision settings analysis – a tool for analysis and design of human activity systems

The paper describes a methodology to be used for analysis and design of human activity systems. The methodology is based on an analysis of the decision settings whereas most other decision analysis methodologies are analysing the process. The decision concept is analysed and discussed. A distinction between programmed and programmable as well as non-programmed and non-programmable decisions is proposed. A classification of different information types for decision making is presented. A methodology based on a systemic and systematic analysis of the information requirements of an organization is proposed. This methodology also indicates organizational discrepancies and information imbalances. The methodology focuses the settings of the decisions on all levels of organizations. The methodology can be regarded as a dynamic, learning system. The author proposes further research on the individuals decision making abilities.     

Decision Making in `Random in a Broad Sense' Environments

It is shown that the uncertainty connected with a `random in a broad sense' (not necessarily stochastic) event always has some `statistical regularity' (SR) in the form of a family of finite-additive probability distributions. The specific principle of guaranteed result in decision making is introduced. It is shown that observing this principle of guaranteed result leads to determine the one optimality criterion corresponding to a decision system with a given `statistical regularity'.     

Differential equation models for statistical functions

Differential equations have been used in statistics to define functions such as probability densities. But the idea of using differential equation formulations of stochastic models has a much wider scope. The author gives several examples, including simultaneous estimation of a regression model and residual density, monotone smoothing, specification of a link function, differential equation models of data, and smoothing over complicated multidimensional domains. This paper aims to stimulate interest in this approach to functional estimation problems, rather than provide carefully worked out methods.     

Standard errors for EM estimation

The EM algorithm is a popular method for computing maximum likelihood estimates. One of its drawbacks is that it does not produce standard errors as a by-product. We consider obtaining standard errors by numerical differentiation. Two approaches are considered. The first differentiates the Fisher score vector to yield the Hessian of the log-likelihood. The second differentiates the EM operator and uses an identity that relates its derivative to the Hessian of the log-likelihood. The well-known SEM algorithm uses the second approach. We consider three additional algorithms: one that uses the first approach and two that use the second. We evaluate the complexity and precision of these three and the SEM in algorithm seven examples. The first is a single-parameter example used to give insight. The others are three examples in each of two areas of EM application: Poisson mixture models and the estimation of covariance from incomplete data. The examples show that there are algorithms that are much simpler and more accurate than the SEM algorithm. Hopefully their simplicity will increase the availability of standard error estimates in EM applications. It is shown that, as previously conjectured, a symmetry diagnostic can accurately estimate errors arising from numerical differentiation. Some issues related to the speed of the EM algorithm and algorithms that differentiate the EM operator are identified.     

A semi-parametric method for estimating the beta coefficients of the hidden two-sided asset return jumps

ABSTRACT

We introduce a new methodology for estimating the parameters of a two-sided jump model, which aims at decomposing the daily stock return evolution into (unobservable) positive and negative jumps as well as Brownian noise. The parameters of interest are the jump beta coefficients which measure the influence of the market jumps on the stock returns, and are latent components. For this purpose, at first we use the Variance Gamma (VG) distribution which is frequently used in modeling financial time series and leads to the revelation of the hidden market jumps' distributions. Then, our method is based on the central moments of the stock returns for estimating the parameters of the model. It is proved that the proposed method provides always a solution in terms of the jump beta coefficients. We thus achieve a semi-parametric fit to the empirical data. The methodology itself serves as a criterion to test the fit of any sets of parameters to the empirical returns. The analysis is applied to NASDAQ and Google returns during the 2006–2008 period.     

Growing up on the sidelines: identity negotiations of Palestinian youth from ‘collaborating’ families relocated to Israel

By examining the experiences of the children of Palestinian collaborators whose families have relocated to Israel, this study explores how youth negotiate self within the context of marginalisation and cultural dislocation. Due to the actions of their parents, the research participants have become outsiders and outcasts in their Palestinian communities of origin, outsiders in Israel, and outsiders among Israeli-Arabs. Based on qualitative, in-depth interviews with 11 Palestinian male youths, we describe and analyse the experience of identity negotiation in the context of fear and their families’ past deceit. Our findings highlight that the youths’ identities are negotiated by engaging in a dialogue of self on belonging and not belonging that is based on visions of their past, present and future selves. This is accompanied by a forced dialogue with others, explaining who they are in order to fit in with the ‘audience’, a presentation that is then acted out.     

Impact of mindful self-care and perceived stress on the health related quality of life among young-adult students in West Virginia

ABSTRACT

There are substantial gaps in research on Health Related Quality of Life (HRQoL) in students aged 18 and above in West Virginia. The purpose of this study is to explore the associations between mindful self-care, perceived stress, and the HRQoL in this population. We conducted a cross-sectional study between March and April 2017. We included participants who were students, aged 18 years and above, living in West Virginia and were able to answer online questions in English. Data was obtained from an online survey using a structured questionnaire, including the SF12v2®, mindful self-care scale- SHORT, and Perceived Stress Scale (PSS)-10. We applied linear regressions to determine the predictors of HRQoL (physical health and mental health) using SF12v2®. 194 participants met the inclusion criteria of the study. Mindful self-care was negatively associated with perceived stress. Better mindful self-care mediated the relationship between perceived stress and psychological well-being, controlling for gender, age, race, marital status, education level, annual household income, and chronic disease status. Perceived stress and mindful self-care were not related to the physical well-being. Better mindful self-care may safeguard against perceived stress among students aged 18 years and above. Our findings in this study recommend more mindfulness-based interventions targeted to this subpopulation to improve psychological well-being.     

Extending Bayesian back-calculation to estimate age and time specific HIV incidence

Lifetime Data Analysis - CD4-based multi-state back-calculation methods are key for monitoring the HIV epidemic, providing estimates of HIV incidence and diagnosis rates by disentangling their...     

On a control chart for the Gini index with simulations

In this work we suggest the use of the Gini index on control charts. The asymptotic properties of Gini index are presented and the control charts based on appropriate confidence intervals are constructed. The suitability of the proposed charts are investigated by means of extensive simulations.