Regularization Paths for Cox's Proportional Hazards Model via Coordinate Descent

We introduce a pathwise algorithm for the Cox proportional hazards model, regularized by convex combinations of l_1 and l_2 penalties (elastic net). Our algorithm fits via cyclical coordinate descent, and employs warm starts to find a solution along a regularization path. We demonstrate the efficacy of our algorithm on real and simulated data sets, and find considerable speedup between our algorithm and competing methods.

Strong rules for discarding predictors in lasso-type problems

We consider rules for discarding predictors in lasso regression and related problems, for computational efficiency. El Ghaoui et al (2010) propose "SAFE" rules that guarantee that a coefficient will be zero in the solution, based on the inner products of each predictor with the outcome. In this paper we propose strong rules that are not foolproof but rarely fail in practice. These can be complemented with simple checks of the Karush- Kuhn-Tucker (KKT) conditions to provide safe rules that offer substantial speed and space savings in a variety of statistical convex optimization problems.Comment:

Carnap's Tolerance and Friedman's Revenge

In this paper, I defend Rudolf Carnap's Principle of Tolerance from an accusation, due to Michael Friedman, that it is self-defeating by prejudicing any debate towards the logically stronger theory. In particular, Friedman attempts to show that Carnap's reconstruction of the debate between classicists and intuitionists over the foundations of mathematics in his book The Logical Syntax of Language, is biased towards the classical standpoint since the metalanguage he constructs to adjudicate between the rival positions is fully classical. I argue that this criticism is mistaken on two counts: (1) it fails to fully appreciate the freedom with regard to the construction of linguistic frameworks that Carnap intended his Principle to embody, and (2) Friedman's objection underestimates the extent to which the evaluation of a framework is task-relative. I conclude that Tolerance is not self-undermining in the way that Friedman claims it is. While this is a restricted conclusion -- and is not a vindication of Carnap's views on logic and mathematics tout court -- it nonetheless suggests that his tolerant perspective has been dismissed too quickly, even by his supporters

Regularization Paths for Cox's Proportional Hazards Model via Coordinate Descent

We introduce a pathwise algorithm for the Cox proportional hazards model, regularized by convex combinations of l1 and l2 penalties (elastic net). Our algorithm fits via cyclical coordinate descent, and employs warm starts to find a solution along a regularization path. We demonstrate the efficacy of our algorithm on real and simulated data sets, and find considerable speedup between our algorithm and competing methods

Vibration Attenuating Medical Platform

Millions of injured people are transported by ambulances each year. While the suspension systems of ambulances dampen the road vibrations felt by the passengers, they do not attenuate the vibration completely. To patients who have compromised physical states, vibration and displacement can aggravate their condition and cause additional pain. Our solution to this societal problem is the Vibration Attenuating Medical Platform (VAMP). VAMP consists of an aluminum and steel structure that is moved with a pneumatic piston. This prototype is designed to fit into existing ambulances and attenuate the vibrations not eliminated by the ambulances suspension. After conducting background research, we found that max displacement in a vehicle is 4 inches. Using a factor of safety of 1.5 we selected a 12-inch stroke length piston, with the neutral piston position at 6 inches extended. A PID control system will be used for the half scale prototype to verify system movement, while a MIMO system is planned as the final full-scale system. No testing was performed on the physical prototype, but extensive analyses were conducted on all components of the system to ensure that they would interface well once assembled

KBART Phase III: Unresolved questions

During the “NISO update” session at the NISO Plus 2021 conference, which took place online due to the COVID-19 pandemic, members of the KBART (Knowledge Base and Related Tools) Standing Committee presented their plans and work toward KBART Phase III, a revision of the KBART Recommended Practice. In an interactive breakout session, they sought input from attendees on how KBART is being used and what new content types it should support. Presenters from the KBART Standing Committee were Noah Levin (Independent Professional), Stephanie Doellinger (OCLC, Inc.), Robert Heaton (Utah State University), and Andrée Rathemacher (University of Rhode Island). Assisting them in preparing the presentation were Jason Friedman (Canadian Research Knowledge Network), Sheri Meares (EBSCO Information Services), Benjamin Johnson (ProQuest), Elif Eryilmaz-Sigwarth (Springer Nature), and Nettie Lagace (NISO)

KBART Unresolved Questions

Presentation, KBART Unresolved Questions , presented at the NISO Plus 2021, Global Conversations, Global Connections conference on February 23, 2021. The conference was held online due to COVID-19. ------- This session was part of the NISO Update: NISO projects are numerous, diverse in output, coverage, and participation, and ACTIVE! This session will support presentations from a small selection of current efforts, all at different stages of their lifecycles. Following project presentations, we will move into breakout rooms for more direct project Q&A and discussions. Speakers: Stephanie Doellinger, Robert Heaton, Noah Levin, Andrée Rathemacher ------- The KBART presentation included an introduction with presentation slides and a breakout discussion using an interactive board on the EasyRetro.io platform. The main session had approximately 140 attendees, and the KBART breakout room had about 33. The link leads to session description at Sched website at https://sched.co/gKIA. A recording of the presentation is available here: https://nisoplus2021.cadmore.media/session/47?passcode=gKIA Additional files include a PDF of presentation slides, the EasyRetro board in multiple formats, screenshots of posts on https://discourse.niso.org/ and Twitter related to the session, and a PDF printout of the entire NISO Plus 2021 conference program schedule

Local Convergence and Global Diversity: From Interpersonal to Social Influence

Axelrod (1997) showed how local convergence in cultural influence can preserve cultural diversity. We argue that central implications of Axelrod's model may change profoundly, if his model is integrated with the assumption of social influence as assumed by an earlier generation of modelers. Axelrod and all follow up studies employed instead the assumption that influence is interpersonal (dyadic). We show how the combination of social influence with homophily allows solving two important problems. Our integration of social influence yields monoculture in small societies and diversity increasing in population size, consistently with empirical evidence but contrary to earlier models. The second problem was identified by Klemm et al.(2003a,b), an extremely narrow window of noise levels in which diversity with local convergence can be obtained at all. Our model with social influence generates stable diversity with local convergence across a much broader interval of noise levels than models based on interpersonal influence.Comment: 20 pages, 3 figures, Paper presented at American Sociological Association 103rd Annual Meeting, August 1-4, 2008, Boston, MA. Session on Mathematical Sociolog