A Note on the Inverse Birthday Problem With Applications

The classical birthday problem considers the probability that at least two people in a group of size N share the same birthday. The inverse birthday problem considers the estimation of the size N of a group given the number of different birthdays in the group. In practice, this problem is analogous to estimating the size of a population from occurrence data only. The inverse problem can be solved via two simple approaches including the method of moments for a multinominal model and the maximum likelihood estimate of a Poisson model, which we present in this study. We investigate properties of both methods and show that they can yield asymptotically equivalent Wald-type interval estimators. Moreover, we show that these methods estimate a lower bound for the population size when birth rates are nonhomogenous or individuals in the population are aggregated. A simulation study was conducted to evaluate the performance of the point estimates arising from the two approaches and to compare the performance of seven interval estimators, including likelihood ratio and log-transformation methods. We illustrate the utility of these methods by estimating: (1) the abundance of tree species over a 50-hectare forest plot, (2) the number of Chlamydia infections when only the number of different birthdays of the patients is known, and (3) the number of rainy days when the number of rainy weeks is known. Supplementary materials for this article are available online.     

Wavelet-based Bayesian nonlinear regression for the air pollution effects on clinic visits in small areas of Taiwan

We revisit the complete clinic visit records and environmental monitoring data at 50 townships and city districts of Taiwan. Extending the earlier analyses, here we consider a Bayesian analysis using Daubechies wavelet. Appropriate model selection is also considered using Bayesian model averaging. Temperature, dew point, and NO₂ and CO of the current day and the previous day are identified as the pollutants in different areas of the island following some spatial pattern.     

Parental financial support and filial responsibility in emerging adulthood: a comparative study between the United States and South Korea

Why do parents provide considerable financial support to their children in college? How do college students feel about their parental financial support and how does it differ between American and Korean cultural contexts? Based on multiple group analysis, we tested the impact of family income and parents’ education on parental tuition and living expenses supports, which in turn affects college students’ perception of filial responsibility across the United States and South Korea. Participants included 179 American college (AC) students from Syracuse University and 268 Korean college (KC) students from Yonsei University Wonju. We found that family income was significantly related to an increase in parental tuition and living expenses supports for both AC and KC students. However, parents’ education was significantly related to an increase in parental tuition and living expenses supports for AC students, but not for KC students. In addition, parental tuition support was related to an increase for filial responsibility, and parental living expenses were related to a decrease in filial responsibility in KC students, but not for AC students. These results indicate that the association between parental financial support and college students’ perception of filial responsibility differs across American and Korean cultural contexts.     

Academic Underachievement and Recovery: Student Perspectives on Effective Career Interventions

Academic achievement has a significant influence on various career development and decision‐making factors. Therefore, it is important for career counselors to understand how past academic underachievement affects students’ current lives and to develop interventions that might ameliorate negative effects. This study examined the experiences of 9 ethnically diverse college students who had experienced and overcome academic failure. Data were collected by individual interviews and analyzed based on the consensual qualitative research method. Four themes emerged in relation to participants’ academic underachievement and recovery: attitude, study strategies, external support, and coping difficulties. The results suggest that underachieving students are better able to cope with and overcome academic difficulties when they set clear career goals, use effective learning strategies, consciously put forth more effort, and receive external support.     

The influence of governance on public sector efficiency: A cross-country analysis

This paper examines whether governance quality affects public sector efficiency in the policy areas of administration, education, infrastructure, and stability. Using cross-country evidence, we find that a country's measures of governance quality are positively and significantly associated with public sector efficiency in the policy areas of administration, infrastructure, and stability. However, regression results suggest that a country's governance quality cannot affect efficiency in the policy area of education, even after controlling for some explanatory variables.     

Distributed manufacturing support systems: the integration of distributed group support systems with manufacturing support systems

Current Manufacturing Support Systems (MSS), such as Computer-aided Manufacturing (CAM) Systems, Computer-aided Design (CAD) Systems, Computer Integrated Manufacturing (CIM) Systems, Material Resource Planning (MRP) Systems, and Manufacturing Accounting Control (MAC) Systems, are mostly independent systems that are operated in limited decision spaces, provide mainly formal and quantitative information, and thus pursue a goal of local optimization. To assist modern manufacturing in meeting the needs for integration, communication, collaboration, and decision making, we introduce the concept of integrating MSS with Distributed Group Support System (DGSS) into a Distributed Manufacturing Support System (DMSS). A rigorous system design approach is taken to model the manufacturing information requirements from a global perspective and pattern decision making processes within the structural (organizational design) and infrastructural (information system design) elements of manufacturing. The result is a conceptual DMSS design that provides an intelligent interface, accommodates incremental manufacturing integration, offers controllable message exchange facilities, and allows configurable communication networks.     

A two-phase approach to estimating time-varying parameters in the capital asset pricing model

Following the development of the economy and the diversification of investment, mutual funds are a popular investment tool nowadays. Choosing excellent targets from hundreds of mutual funds has become more and more crucial to investors. The capital asset pricing model (CAPM) has been widely used in the capital cost estimation and performance evaluation of mutual funds. In this study, we propose a new two-phase approach to estimating the time-varying parameters of CAPM. We implemented a simulation study to evaluate the efficiency of the proposed method and compared it with the commonly used state space and rolling regression methods. The results showed that the new method is more efficient in most scenarios. Meanwhile, the proposed approach is very practical and it is unnecessary to judge and adjust the estimating process for different situations. Finally, we applied the proposed method to equity mutual funds in the Taiwan stock market and reported the performances of two funds for demonstration.     

Policy is not enough – the influence of the gendered workplace on fathers’ use of parental leave in Sweden

ABSTRACT

Paid parental leave for fathers is a promising social policy tool for degendering the division of labor for childcare. Swedish fathers have had the right to paid parental leave since 1974, but they take only one-fourth of leave days parents take. There are strong cultural norms supporting involved fatherhood, so couples typically want to share leave more than they do. This article explores how workplaces can constrain Swedish fathers’ use of state leave policy, in ways that fathers can take for granted, a topic that has received less attention than individual or family-related obstacles. Based on interviews with 56 employees in five large private companies, we found that masculine workplace norms can make it difficult for fathers to choose to take much leave, while aspects of traditional workplace structure building on these norms can negatively affect fathers’ capabilities of taking much leave. Workplace culture and structure seemed to be based on assumptions that the ideal worker should prioritize work and has limited caregiving responsibilities, setting limits to fathers’ ability to share leave with mothers. Gender theorists suggest such assumptions persist because of male dominance at the workplace and the endurance of gendered assumptions about the roles of men and women.     

Asymptotics for a class of generalized multicast autoregressive processes

We propose a new class of generalized multicast autoregressive (GMCAR, for short, hereafter) models indexed by a multi-casting tree where each individual produces exactly the same number of offspring. This class includes standard bifurcating autoregressive processes (BAR, cf. Cowan and Staudte (1986)) and multicast autoregressive (MCAR, cf. Hwang and Choi (2009)) models as special cases. Accommodating non-Gaussian, non-negative and count data, the class includes various models such as nonlinear autoregression, conditionally heteroscedastic process and conditional exponential family. The pathwise stationarity of the GMCAR model is discussed. A law of large numbers and a central limit theorem are established which are in turn used to derive asymptotic distributions associated with martingale estimating functions.