Improving Parametric Mortgage Prepayment Models with Non-parametric Kernel Regression

Developing a good prepayment model is a central task in the valuation of mortgages and mortgage-backed securities but conventional parametric models often have bad out-of-sample predictive ability. A likely explanation is the highly non-linear nature of the prepayment function. Non-parametric techniques are much better at detecting non-linearity and multivariate interaction. This article discusses how non-parametric kernel regression may be applied to loan level event histories to produce a better parametric model. By utilizing a parsimonious specification, a model can be produced that practitioners can use in valuation routines based on Monte Carlo interest rate simulation.

The use of aerial photographs for estimating school sizes of cetaceans

ENGLISH: The accuracy and precision of dolphin school size estimates based on aerial photograph counts were examined using data collected on recent aerial and ship surveys. These estimates were found to be accurate during a 1979research cruise aboard a tuna purse-seiner; dolphin schools were photographed from the ship’s helicopter, encircled with the purse-seine, and then counted as the dolphins were released from the net. A comparison of photographic estimates with these counts indicated that the relationship was fairly close and gave no indication of significantly differing from 1:1. During a 1980 aerial study, photographic estimates from different schools, passes, and camera formats were compared and were found to be quite precise with a standard deviation of approximately 60/0 of school size. Photographic estimates were also compared with estimates made by aerial observers. Most observers tended to underestimate school size, particularly for large schools. The variability among observers was high, indicating that observers should be individually calibrated. SPANISH: Se examinó la exactitud y la precisión de las estimaciones de la magnitud de los cardúmenes de delfines basadas en el cálculo de las fotografías aéreas, usando los datos obtenidos en los últimos reconocimientos aéreos y de los barcos. En 1979, durante un crucero de investigación en un cerquero atunero, se encontró que estas estimaciones eran acertadas; se fotografiaron los cardúmenes de delfines desde un helicóptero del barco, cercados con la red y luego se contaron a medida que se libraban los delfines de la red. Una comparación de las estimaciones fotográficas con estos cálculos indicó que la relación era bastante aproximada y no hubo indicación que se diferenció significativamente de la razón 1:1. Durante un estudio aéreo en 1980, se compararon las estimaciones fotográficas de diferentes del cardúmenes, en los pases y los formatos de las cámaras y se encontró que eran bastante precisos, con una desviación normal de cerca del 60/0 de la magnitud cardumen. Se compararon también las estimaciones fotográficas con las estimaciones realizadas por los observadores aéreos. La mayoría de los observadores tienden a subestimar la magnitud de los cardúmenes, especialmente los cardúmenes grandes. La variabilidad entre los observadores fue elevada, lo que indica que se deben calibrar individualmente los datos de observadores. (PDF contains 39 pages.

A Scale for Assessing Self-Concept of Perception of Independence in Learning and Its relationship to Underachievement in Intermediate Grades

A total study consisting of three parts was conducted at Hebeler Elementary School (HES) , the laboratory school for Central Washington State College (CWSC). The study was concerned with the measurement and development of independence in learning with intermediate grade students

Calcium responses of chicken trigeminal ganglion neurons to methyl anthranilate and capsaicin

Using digital fluorescence imaging, we determined the effects of methyl anthranilate (MA), an avian irritant, and capsaicin (CAP), a mammalian irritant, on intracellular calcium ([Ca2+]i) in chicken trigeminal neurons. Concentration–response functions indicated that the threshold for inducing increases in [Ca2+]i was higher for CAP (30·mmol·l–1) than for MA (10·mmol·l–1). The maximum magnitudes of [Ca2+]i in response to MA and CAP were compared after normalization to 40·mmol·l–1 KCl. At equal concentrations (300·mmol·l–1), trigeminal neurons responded with a greater change in [Ca2+]i to MA (78% of KCl) than to CAP (43% of KCl). Furthermore, at 300·mmol·l–1, 48% of neurons responded to MA whereas only 16% responded to CAP. The increases in [Ca2+]i induced by both MA and CAP were dependent upon extracellular calcium. While the calcium responses to MA were also dependent on extracellular sodium, responses to CAP were not. There were separate but overlapping populations of neurons sensitive to MA and CAP. Taken together, the higher threshold concentration of CAP, the higher response magnitude to MA than CAP and the greater number of neurons sensitive to MA than CAP provide a rationale for the observed behavioral differences of birds to these two compounds. Finally, the findings that the calcium responses to MA and CAP have different ion dependencies and that there are separate populations sensitive to these compounds suggest different transduction mechanisms mediating chicken trigeminal responses to MA and CAP

Stochastic Feature Selection with Distributed Feature Spacing for Hyperspectral Data

Feature subset selection is a well studied problem in machine learning. One short-coming of many methods is the selection of highly correlated features; a characteristic of hyperspectral data. A novel stochastic feature selection method with three major components is presented. First, we present an optimized feature selection method that maximizes a heuristic using a simulated annealing search which increases the chance of avoiding locally optimum solutions. Second, we exploit local cross correlation pair-wise amongst classes of interest to select suitable features for class discrimination. Third, we adopt the concept of distributed spacing from the multi-objective optimization community to distribute features across the spectrum in order to select less correlated features. The classification performance of our semi-embedded feature selection and classification method is demonstrated on a 12-class textile hyperspectral classification problem under several noise realizations. These results are compared with a variety of feature selection methods that cover a broad range of approaches. Abstract © IEE

Community of practice among faculty team-teaching education doctorate (ED.D.) students: A reflective study

Aim/Purpose The purpose of the study was to contribute to knowledge about the ways in which incorporating a Community of Practice into doctoral seminar teaching and course management could be a practical and sustainable path to professional development for doctoral faculty aspiring to become stewards of the practice of teaching. Background This report documents a reflective self-study conducted by four professors engaged in a community of practice while team-teaching a linked pair of EdD seminars on action research at Arizona State University. Methodology This reflective study used field notes and written reflections as its sources of data to examine how participants’ identities as professors of education changed during and after participating in a team-taught professional doctoral pair of courses. Contribution An important goal of the community of practice was to promote faculty professional development as stewards of the practice of teaching. Engaging in disciplined reflection on teaching is uncommon in American graduate education and rarely documented in the literature of post-compulsory education. Findings Analysis of post-hoc reflective accounts and contemporaneous notes revealed a general pattern of gradual transformation by the teaching team members. The professors moved from anxious concern about appearing competent to growing confidence and appreciation for the potential of a community of practice to provide significant professional benefits to students and faculty. Salutary features of reflective team teaching in a community of practice persist in participants’ subsequent teaching practice. Recommendations Reported benefits include eagerness for team teaching, increased openness to for Practitioners pedagogical suggestions from peers, comfort with being observed by colleagues while teaching, and willingness to revise plans when initial plans and practices are not working effectively for students. Recommendations Data analysis and testimony support the claim that engaging in a CoP, in this for Researchers case, did support their identity transformation as stewards of their own practice as instructors and professors of education. However, the study design does not support a claim that most or all future Communities of Practice in doctoral education will produce similar salutary results. Testing this proposition will require additional research in settings and programs different from the one represented here. Impact on Society Implementing communities of practice in doctoral programs can make room for professional development for both the faculty team and for the students. Future Research Further studies could be conducted to document the ways in which other communities of practice can be used to develop faculty instructors in masters and doctoral programs and in undergraduate education. © 2021 Informing Science Institute. All rights reserved

Regulatory and Governance Impacts on Bank Risk-Taking

Risk in financial institutions is vitally important to regulators, policy makers, investors, and the stability of the financial system, yet some critical aspects of that risk remain poorly understood. In the case of U.S. startup banks, a critical choice that can influence risk-taking behavior is which of three regulators—with varying levels of stringency—to choose. The board of directors of the new bank makes this important decision, which may result in different risk implications, depending on board’s structure. Here, we examine banks’ risk behavior associated with the degree of board independence and the choice of regulator. We find that the regulatory environment and board independence jointly influence new bank risk. Our evidence suggests that the intensity of regulatory scrutiny is a partial substitute for board independence in achieving an optimal level of risk. We discuss the implications of our findings for theory and policy

The Effect of Smoking on Kentucky’s Workforce

Excerpt from the Executive Summary: Smoking has been estimated to increase health care costs in the United States by $167.5 billion annually (Xu et al. 2015). In Kentucky, smoking adds$2.5 billion in health care expenditures each year. Most of these costs were paid by public programs such as Medicaid and Medicare. While these costs are significant, they represent only a portion of the costs that smoking imposes on society. Smoking also leads to poorer labor market outcomes. Smokers are more likely to be unemployed, earn lower wages, and die prematurely than non-smokers. These negative labor market effects reduce economic activity and lower tax revenues, adding to the social costs and fiscal impact that smoking imposes. Past research shows that smokers generally earn four to eleven percent less than similar nonsmokers. Some of this wage penalty is due to the negative health consequences of smoking. Smoking can reduce workers’ health, causing them to be less productive, have higher health insurance costs, and incur greater rates of absenteeism. As a result, smokers tend to earn lower wages. However, the wage penalty might also reflect differences between those who decide to smoke and those who do not rather than being caused directly by smoking