Exploring Investor Attention in Financial Models

The purpose of this study is to investigate whether stock prices are influenced by investor attention and how this, in turn, can be used to better advise the financial decisions of the everyday investor. Using weekly adjusted close data, weekly traded volumes, and weekly company searches using Google Trends, I tested my hypothesis that including the frequency of company searches, found through consumers using Google, in financial models will help better predict stock returns. Using S&P 500 company data from February 2012 to February 2017, frequency is a better predictor of price in comparison to trading volumes. But, to maximize predictability, both frequency and volume should be used to predict price. Further investigation revealed that the Health Care and Energy sectors tend to have the strongest correlation between frequency and volume, compared to the Consumer Staples and Utilities sectors, which tend to attract individual investors

Verifying the Accuracy of Regional Models Used in Transportation and Air Quality Planning, MTI 02-03

Communities with air quality problems in California and across the nation are proposing major beltway and highway projects to address roadway congestion problems. However, the travel and emissions models used in conformity analyses and environmental impact statements have low accuracy. Travel demand models are typically estimated on and calibrated to observed data, but rarely validated against observed data not used in their estimation and calibration. Validation of a model is critical to determining the degree of precision to which it can be reasonably applied. In this historical forecasting case study in the Sacramento, California region, the original version of the Sacramento regional travel demand model (estimated with 1991 data) is used with Year 2000 observed data to validate the model over a nine-year period. Three simulations are performed to test, respectively, model accuracy, the effect of errors in socioeconomic/land use projections, and induced travel. The results of the study suggest that the travel demand model (that is, its functional forms and parameters) overestimates vehicle miles traveled, vehicle hours traveled, and vehicle hours of delay (5.7, 4.2, and 17.1 percent, respectively). The errors in the socioeconomic/land use projections made in 1991 and used in the model approximately double the errors in vehicle travel. The model also underestimates induced travel (elasticity of 0.14) compared to the estimate of actual induced travel (elasticity of 0.22) in this study, but the upward bias in the model error swamps this underestimation. If the model were used for conformity analyses in this region, its overestimation of daily vehicle travel should provide a relatively generous margin of error with respect to meeting air quality emissions budgets. (Note that the version of the model used in this study is no longer used by the region.) On the other hand, in the analysis of travel effects of proposed highway investment projections in environmental impact statements, the overestimation of the daily travel results would tend to overestimate no-build travel demand and congestion and thus the need for new highway projects in the region. Compared to that in the no-build alternative, the magnitude of change for the highway alternative would have to be greater than the model error to be considered significantly different. This may be a difficult standard for the typical new highway project to meet

Nonlinarity of Boolean functions and hyperelliptic curves

We study the nonlinearity of functions defined on a finite field with 2^m elements which are the trace of a polynomial of degree 7 or more general polynomials. We show that for m odd such functions have rather good nonlinearity properties. We use for that recent results of Maisner and Nart about zeta functions of supersingular curves of genus 2. We give some criterion for a vectorial function not to be almost perfect nonlinear

Differentially 4-uniform functions

We give a geometric characterization of vectorial boolean functions with differential uniformity less or equal to 4

Model-based Transportation Performance: A Comparative Framework and Literature Synthesis, Research Report 11-09

In an era of limited resources and a proliferation of data, there is increasing pressure to conduct careful evaluations of the economic, environmental, and equity effects of investments and policies that influence transportation and land-use systems. This report compares performance measures recommended to achieve desired goals and reviews the literature to determine the degree to which these measures have been implemented and what they indicate about the relative effectiveness of land-use, transit, and automobile pricing policies. Despite the variation in methods and performance measures implemented in the studies reviewed for this report, the synthesis of study results suggests the direction and relative magnitude of change resulting from different types of policies, as well as potential biases introduced by omitting the representation of the land-use and transportation interaction. Overall, the performance measures indicate that carefully designed transit, land-use, and automobile pricing policies may improve travel, economic, environmental, and equity conditions for communities. However, transit and peak-period automobile pricing policies can, in some situations, lead to negative performance outcomes across some or all measures, as illustrated in studies that explicitly represent the land-use and transportation interaction

Ride-Hailing Holds Promise for Facilitating More Transit Use in the San Francisco Bay Area

Increasing transit use has many benefits, including reducing traffic congestion and greenhouse gas (GHG) emissions. However, riders need to be able to get to a station in order to use transit. Walking is an option only for those within a limited radius of a station. Driving to a station may be feasible for some, but providing sufficient parking can be expensive and land intensive. The rise of ride-hailing companies such as Uber and Lyft presents a new opportunity for bridging the “first-mile” gap to high quality transit. Transit agencies are beginning to launch pilot projects to test public-private partnerships with ride-hailing companies to increase access to transit.This policy brief summarizes findings from researchers at UC Davis who used existing modeling tools and data to understand the potential market demand for a first-mile transit access service in the San Francisco Bay Area. They modeled the likelihood of commuters who drive alone to switch to using ride-hailing and the Bay Area Rapid Transit (BART) rail system to get to work based on travel time, cost, and distance to a BART station. They explored the magnitude of change in overall travel time and cost for travelers who switch from driving alone to using ride-hailing and BART, as well as potential changes to vehicle miles traveled (VMT) and GHG emissions at both the regional and station level.View the NCST Project Webpag

Transit Performance Measures in California

This research is the result of a California Department of Transportation (Caltrans) request to assess the most commonly available transit performance measures in California. Caltrans wanted to understand performance measures and data used by Metropolitan Planning Organizations (MPOs) and transit agencies to help it develop statewide measures. This report serves as a summary reference guide to help Caltrans understand the numerous and diverse performance measures used by MPOs and transit agencies in California. First, investigators review the available literature to identify a complete transit performance framework for the purposes of organizing agency measures, metrics, and data sources. Next, they review the latest transit performance measures documented in planning reports for the four largest MPOs in California (San Francisco Bay Area, Los Angeles, San Diego, and Sacramento). Researchers pay special attention to the transit performance measures used by these MPOs, because these measures are available for the majority of California’s population. Finally, investigators summarize 231 performance measures used by a total 26 local transit agencies in the State of California, based on transit planning documents available on the internet

Video Transit Training for Older Travelers: A Case Study of the Rossmoor Senior Adult Community, California, MTI Report 06-04

In this study, the authors applied principles of social learning and marketing to develop a transit training video for residents of the Rossmoor senior adult community in California . The video features familiar community members successfully navigating specific concerns and problems related to transit use in accessing key community destinations (shopping, health care, and the nearest Bay Area Rapid Transit district station). To evaluate the effectiveness of the video, residents were recruited to complete questionnaires before and after viewing it. Video messages aimed to educate viewers on how to obtain transit information, costs, and payment generated a significant and positive attitudinal change. However, respondents reported that the video did not adequately address the difficulties associated with reading schedules and climbing stairs at transit stations. Survey results also indicate a significant and positive change in respondents’ future use of a broader range of Internet-related information sources. The results also reveal a significant and positive change among respondents in using transit services to the specific destinations presented in the video. However, results are mixed on whether participants might take transit to general destinations not explicitly presented in the video

Bounds on the degree of APN polynomials The Case of x−1+g(x)x^{-1}+g(x)

We prove that functions f:\f{2^m} \to \f{2^m} of the form $f(x)=x^{-1}+g(x)$ where $g$ is any non-affine polynomial are APN on at most a finite number of fields \f{2^m}. Furthermore we prove that when the degree of $g$ is less then 7 such functions are APN only if $m \le 3$ where these functions are equivalent to $x^3$