Machine Learning Vasicek Model Calibration with Gaussian Processes

In this article, we calibrate the Vasicek interest rate model under the risk neutral measure by learning the model parameters using Gaussian processes for machine learning regression. The calibration is done by maximizing the likelihood of zero coupon bond log prices, using mean and covariance functions computed analytically, as well as likelihood derivatives with respect to the parameters. The maximization method used is the conjugate gradients. The only prices needed for calibration are zero coupon bond prices and the parameters are directly obtained in the arbitrage free risk neutral measure.     

Generalised K-S confidence regions: some exact results

One-sided confidence regions for continuous cumulative distribution function are constructed using empirical cumulative distribution functions and the generalized Kolmogorov-Smirnov distance. The band width of such regions becomes narrower in the right or left tail of the distribution. Significance levels necessary for implementation are given. Some other K-S type distances useful in constructing a confidence region with nonconstant width are also included.     

Optimal control strategies for dividend payments and capital injections in compound Markov binomial risk model with penalties for deficits

We consider the compound Markov binomial risk model. The company controls the amount of dividends paid to the shareholders as well as the capital injections in order to maximize the cumulative expected discounted dividends minus the discounted capital injections and the discounted penalties for deficits prior to ruin. We show that the optimal value function is the unique solution of an HJB equation, and the optimal control strategy is a two-barriers strategy given the current state of the Markov chain. We obtain some properties of the optimal strategy and the optimal condition for ruining the company. We offer a high-efficiency algorithm for obtaining the optimal strategy and the optimal value function. In addition, we also discuss the optimal control problem under a restriction of bounded dividend rates. Numerical results are provided to illustrate the algorithm and the impact of the penalties.     

Social capital of entrepreneurs in a developing country: The effect of gender on access to and requests for resources

This paper addresses gender differences in the social capital of entrepreneurs in a developing country. Social networks are often an important asset for accessing resources; however, they may also be a liability in developing countries, since entrepreneurs are often expected to support their contacts. Using a recent survey among urban and rural Ugandan entrepreneurs, we focus on the financial resources that entrepreneurs can obtain from their contacts on the one hand, and requests for financial support made to the entrepreneurs from these contacts on the other hand. Our results show that there are gender differences associated with access to, and requests for, financial resources.     

专科英语应用能力测试中增加口试的必要性

本文从语言学、教育学、心理学、英语教学法及英语教学实践等的角度 ,多方阐述了专科英语教学中口语训练的重要性 ,并论证了专科英语应用能力测试中增加口试的必要性     

浅析高中数学有效教学的内涵、特征及实施策略

高中数学有效教学的涵义即在数学课程标准基本理念的指导下，促进学生数学学习、提高学生数学素养、促成学生终身发展．高中数学有效教学的主要特征是教学目标有效、教学过程有效、教学方式有效、教学结果有效。主要实施策略是，以引导探究为依托，实现有效的知识建构；以暴露思维作平台，实现有效的思维训练；以激发兴趣作前提，实现有效的情意驱动．     

欧洲债务危机的主要成因分析

肇始于希腊的欧洲债务危机到目前为止都没有停息的迹象,甚至还呈蔓延之势。欧洲债务危机爆发的直接原因是在金融危机的背景下,政府支出规模持续扩大,导致财政赤字居高不下,最终使得国债规模超过政府的偿还能力,出现明显的违约可能性。同时,国际竞争力不足,导致出口受阻,使得资金问题更加严重。从更深层次看,产业结构不合理,经济发展速度缓慢,过低的投资率和储蓄率及过高的储蓄投资转化率,都是导致欧债危机的重要原因。     

‘You Get More Respect,’ Reasons for Sex Among African American High School Youth: A Qualitative Study

ABSTRACT

African American adolescents continue to be disproportionately impacted by HIV, sexually transmitted infections (STIs), and unanticipated pregnancies. In-depth, face-to-face interviews among a convenience sample of 32 African American adolescents (16 male and 16 female) were used to explore the reasons why some adolescents decided to engage in sex while others chose to delay sexual debut. Data were analyzed using a thematic analysis. Among the overall sample, psychological motivations, external pressure, physical pleasure seeking, and relationship-related motivations were the major themes cited for engaging in sex by participants and their friends. External support, motivation to avoid negative consequences, not feeling ready or lacking interest in sex, and having negative views about sex were among the major reasons for delaying sex. Several of the emergent themes showed gender differences. Suggestions for future research include the need for sexual education, and STI/HIV prevention programs that are gender sensitive and flexible enough to accommodate multiple factors related to sexual debut.     

Chapter 5 Impacts of Profit Status of Assisted Living Facilities

Abstract

Florida is a bellwether state in terms of the need for assisted living among elderly persons and has more than 2,000 of the nation's estimated 11,459 assisted living facilities (ALFs). The authors of this article surveyed 140 ALFs in Florida in order to examine the relationship of profit status to ownership of other facilities, willingness to serve low income groups, formal policies, and persons involved in decisions about resident retention. Significant differences were found between for-profit and non-profit facilities in terms of ownership of nursing homes and resident involvement in retention decisions. A discussion of how the profit motive and formal policies can impact residents concludes the article.     

Bootstrap method in ranking and slippage problems

In this paper, the bootstrap method of Efron (1979) is given for a ranking and a slippage problem, where the ranking (or slippage) is with respect to the mean of the distributions. The method is also applied to obtain a confidence interval for the largest mean.