Parameter estimation of Lindley step stress model with independent competing risk under type 1 censoring

Abstract

In literature, Lindley distribution is considered as an alternative to exponential distribution to fit lifetime data. In the present work, a Lindley step-stress model with independent causes of failure is proposed. An algorithm to generate random samples from the proposed model under type 1 censoring scheme is developed. Point and interval estimation of the model parameters is carried out using maximum likelihood method and percentile bootstrap approach. To understand the effectiveness of the resulting estimates, numerical illustration is provided based on simulated and real-life data sets.     

Analysis of some ruin-related quantities in a Markov-modulated risk model

In this paper, we study the joint Laplace transform and probability generating function of some random quantities that occur in each environment state by the time of ruin in a Markov-modulated risk process. These quantities include the duration spent in each state, the number of claims and the aggregate amount of claims that occurred in each state by the time of ruin. Explicit formulae for the joint transforms, given the initial surplus, and the initial and terminal environment states, are expressed in terms of a matrix version of the scale function. Moments and covariances of these ruin-related quantities are obtained and numerical illustrations are presented. The joint transform of the duration spent in each state, the number of claims, and the aggregate amount of claims that occurred in each state by the time the surplus attains a certain level are also investigated.     

On conditional risk estimation considering model risk

Usually, parametric procedures used for conditional variance modelling are associated with model risk. Model risk may affect the volatility and conditional value at risk estimation process either due to estimation or misspecification risks. Hence, non-parametric artificial intelligence models can be considered as alternative models given that they do not rely on an explicit form of the volatility. In this paper, we consider the least-squares support vector regression (LS-SVR), weighted LS-SVR and Fixed size LS-SVR models in order to handle the problem of conditional risk estimation taking into account issues of model risk. A simulation study and a real application show the performance of proposed volatility and VaR models.     

Gambling Behavior of Student-Athletes and a Student Cohort: What are the Odds?

This study investigated the prevalence of gambling, gambling related NCAA violations, and disordered gambling in student-athletes (n = 736) with a comparison cohort of students (n = 1,071) at four universities. Student-athletes reported similar rates of gambling frequency, use of a bookmaker, and disordered gambling as students. After accounting for demographic differences, student-athletes were less likely to engage in sports wagering than students. Several risk factors for disordered gambling were identified, including being male and reporting at least one parent with a history of gambling problems. These findings suggest that problems associated with gambling are a university-wide issue with student-athletes meriting additional attention because of implications for the integrity of intercollegiate sports. Improved prevention and intervention efforts for collegiate gambling are recommended.     

Child protection decision-making

The effects of interagency collaboration on risk assessment in child protection practice were analysed in respect of the decision-making processes in child death inquiries. Universal features in the assessment of risk as identified in psychological literature were applied; in particular, the concepts of ‘groupthink’, the ‘certainty effect’ and ‘group polarization’. It is suggested that case conference decisions are inherently more risky than those taken by professionals with individual responsibility because of the way in which cases are framed in terms of losses.     

Demand for decision autonomy and the desire to avoid responsibility in risky environments: Experimental evidence

This paper experimentally studies individuals’ willingness to pay for the authority to make risky decisions for themselves, and the willingness to take responsibility for others, as primary determinants of leadership willingness. We consider a setup involving a pair of individuals, where one individual is designated to make both parties’ decisions by default. Depending on treatment, either party can express a willingness to pay to change this situation. If one’s willingness to pay to make her own decision herself is positive (negative), we interpret it as a demand for autonomy (a desire to delegate). On the flip side, if one’s willingness to pay to avoid making a decision on behalf of another person is positive (negative), we interpret it as a desire to avoid responsibility (a demand for authority). We find that on average, individuals are willing to pay positive amounts of money to make their decisions themselves, and incur positive but smaller opportunity costs for the right to make decisions for others. Certain individual and contextual characteristics emerge as important predictors. Notably, (1) men are more likely to demand both autonomy and authority at the same time, (2) individuals with other regarding preferences are more likely to pay to avoid taking responsibility for others’ decisions when the probability of loss is high. Exploring differences between individuals’ own decisions and the decisions they make on behalf of others, we find that subjects with other-regarding preferences tend to “cautious-shift” when making decisions on behalf of others. Also, we find that individuals who would like to avoid responsibility also tend to “shift” their decisions when put in a decision-making role. The results have implications for the allocation of decision-making authority in pairs and leadership.     

Parenting Style,Child Emotion Regulation and Behavioral Problems: The Moderating Role of Cultural Values in Australia and Indonesia

Abstract

Research has shown that the congruence of parenting styles with cultural values, rather than parenting styles alone, impacts child adjustment. This study examined if parents’ cultural values moderate the relationships between parenting styles and child outcomes across both an individualist culture (Australia) and a collectivist culture (Indonesia). Three hundred and eighty-seven parents of 2–10-year-old children from both countries reported their parenting styles, the importance of the collectivistic values (security, conformity, and tradition), and their child's emotion regulation and behavioral problems. In both countries, authoritative parenting was associated with higher child emotion regulation and lower levels of behavioral problems, and authoritarian parenting was associated with lower child emotion regulation and higher levels of behavioral problems. Although cultural values did not moderate the relationship between authoritarian parenting and child adjustment, in both countries greater importance placed on tradition attenuated the positive effect of authoritative parenting on child outcomes.     

Double and group acceptance sampling plan for truncated life test based on inverse log-logistic distribution

This paper introduces a double and group acceptance sampling plans based on time truncated lifetimes when the lifetime of an item follows the inverse log-logistic (ILL) distribution with known shape parameter. The operating characteristic function and average sample number (ASN) values of the double acceptance sampling inspection plan are provided. The values of the minimum number of groups and operating characteristic function for various quality levels are obtained for a group acceptance sampling inspection plan. A comparative study between single acceptance sampling inspection plan and double acceptance sampling inspection plan is carried out in terms of sample size. One simulated example and four real-life examples are discussed to show the applicability of the proposed double and group acceptance sampling inspection plans for ILL distributed quality parameters.     

小微企业网贷风险定价模型研究

对小微企业网贷平台的运营模式进行深入分析,发现其运行机制包括需求的同质化解构、需求的模块化生产、需求的风险评估、个性化需求加总,在此基础上构建小微企业网贷风险定价模型。为验证模型的有效性,抽取国内典型互联网金融平台“人人贷”上近期发生的小微企业标的并进行风险定价,将定价结果与实际利率进行比较,发现该模型适用于“卖方市场”的小微企业网贷,能够提供差异化的贷款利率,从而向小微企业提供个性化的网贷产品。     

Macro-Economic Factors in Credit Risk Calculations: Including Time-Varying Covariates in Mixture Cure Models

The prediction of the time of default in a credit risk setting via survival analysis needs to take a high censoring rate into account. This rate is because default does not occur for the majority of debtors. Mixture cure models allow the part of the loan population that is unsusceptible to default to be modeled, distinct from time of default for the susceptible population. In this article, we extend the mixture cure model to include time-varying covariates. We illustrate the method via simulations and by incorporating macro-economic factors as predictors for an actual bank dataset.