A Robust Quantile Huber Loss With Interpretable Parameter Adjustment In Distributional Reinforcement Learning

Distributional Reinforcement Learning (RL) estimates return distribution mainly by learning quantile values via minimizing the quantile Huber loss function, entailing a threshold parameter often selected heuristically or via hyperparameter search, which may not generalize well and can be suboptimal. This paper introduces a generalized quantile Huber loss function derived from Wasserstein distance (WD) calculation between Gaussian distributions, capturing noise in predicted (current) and target (Bellman-updated) quantile values. Compared to the classical quantile Huber loss, this innovative loss function enhances robustness against outliers. Notably, the classical Huber loss function can be seen as an approximation of our proposed loss, enabling parameter adjustment by approximating the amount of noise in the data during the learning process. Empirical tests on Atari games, a common application in distributional RL, and a recent hedging strategy using distributional RL, validate the effectiveness of our proposed loss function and its potential for parameter adjustments in distributional RL. The implementation of the proposed loss function is available here.Comment: 6 pages, 1 figure, to be published in ICASSP 202

Rugby sevens match demands and measurement of performance: A review

© 2018, University of Zagreb - Faculty of Kinesiology. All rights reserved. The purpose of this review is to summarize the research that has examined the match demands of elite-level, men’s rugby sevens, and provide enhanced understanding of the elements contributing to successful physical and technical performance. Forty-one studies were sourced from the electronic database of PubMed, Google Scholar and SPORTDiscus. From these, twelve original investigations were included in this review. Positive match outcomes are the result of an interplay of successful physical, technical, and tactical performances. The physical performance of players (activity profile measurement from GPS) includes high relative total distance and high-speed distance values in comparison to other team sports. The technical performance of players (skill involvement measurement from match statistics) involves the execution of a range of specific offensive and defensive skills to score points or prevent the opponent from scoring. The factors influencing change in these performance constructs has not been investigated in rugby sevens. There is a paucity in the literature surrounding the situational and individual factors affecting physical and skill performance in elite rugby sevens competition. Future studies should investigate the factors likely to have the strongest influence on player performance in rugby sevens. This should include larger sample sizes and account for repeated measures within players. This will allow coaches and scientists to improve their interpretation of activity and skill profile data, and make more informed decisions on players’ athletic preparation program

Hillslope Asymmetry Maps Reveal Widespread, Multi-Scale Organization

Hillslope asymmetry is the condition in which oppositely-facing hillslopes within an area have differing average slope angles, and indicates aspect-related variability in hillslope evolution. As such, the presence, orientation and magnitude of asymmetry may be a useful diagnostic for understanding process dominance. We present a new method for quantifying and mapping the spatial distribution of hillslope asymmetry across large areas. Resulting maps for the American Cordillera of the Western Hemisphere and the western United States reveal that hillslope asymmetry is widespread, with distinct trends at continental to drainage scales. Spatial patterns of asymmetry correlate with latitude along the American Cordillera, mountain-range orientation for many ranges in the western United States, and elevation in the Idaho Batholith of the Northern Rocky Mountains. Spatial organization suggests that non-stochastic, process-driven controls cause these patterns. The hillslope asymmetry metric objectively captures previously-documented extents and frequencies of valley asymmetry for the Gabilan Mesa of the central California Coast Range. Broad-scale maps of hillslope asymmetry are of interest to a wide range of disciplines, as spatial patterns may reflect the influence of tectonics, atmospheric circulation, topoclimate, geomorphology, hydrology, soils and ecology on landscape evolution. These maps identify trends and regions of hillslope asymmetry, allow possible drivers to be spatially constrained, and facilitate the extrapolation of site-specific results to broader regions

A Review of: “Leah Vande Berg & Nick Trujillo, Cancer and Death: A Love Story in Two Voices.”

A review of the book “Cancer and Death: A Love Story in Two Voices” by Leah Vande Berg and Nick Trujillo

My Father’s Ghost: A Story of Encounter and Transcendence

This autoethnography is about my personal search for my father, who was an early presence in my life, but who gradually became a palpable absence. In many ways, I have been searching for my father all my life, and somehow hoping to rekindle a relationship that I have experienced mostly as something I lost early. As my search progressed across a span of more than fifty years, I found my father in the one place I least expected. In this article, I begin to write my father in a new light, one that offers insights into his legacy for me, and for my sons. In the end, I hope to write our lives in a way that captures just a bit of the spirit of my spirited father

Review of the book, Prejudiced communication: A social psychological perspective

The race problem is solved. Racism is dead. Now we just have the backlash problem: too many groups pushing too hard for special rights and special status. These, at least, are the beliefs of the "modern racist," according to Janet Ruscher

Writing Through the Memories: Autoethnography as a Path to Transcendence

This autoethnography is about writing through the sometimes difficult or traumatic memories that show up in my life from time to time. It is about narrative healing and transformation through the practice of autoethnographic writing

Disruption, Silence, and Creation: The Search for Dialogic Civility in the Age of Anxiety

This article searches the contours of anxiety, asking whether anxiety can serve as a springboard to creative engagement in dialogue. Specifically, the article explores the university classroom as a possible site where anxiety might be transformed into the spark of creation. Three opportune moments are examined—disruption, silence, and creation— for the possibilities they present for creating new spaces of energy and new engagement with the call of alterity that erupts in human encounter. The encounter with an “Other” who calls to us from across a chasm of difference—a call that demands a response—is the opening to the possibility of creative engagement that can lead to new levels of transcendence in the classroom and beyond

Joy Notes

In this essay, I attempt to write the emergence of joy in my life, as I have stumbled into it, in little flashes and glimpses, in minor notes and in waves. I do not think that joy can be more than ephemeral, though I seek here to embrace it, to hold it, to celebrate it when it appears

Spirited Accidents: An Autoethnography of Possibility

Kierkegaard says, "A human being is spirit. But what is spirit? Spirit is the self. But what is the self? The self is a relation …" This understanding of spirit-as-self-in-relation, leads, inevitably, to concerns for personal fulfillment, dialogue, community, and social justice in our world. To engage spirit in our ethnographic practice is to engage the self in relation —with the world, with others, with the very frames and possibilities of our being. The accidental ethnographer, open to the driving pulse of spirited searching, may stumble into openings never anticipated. Following these openings may lead to transcendent experiences that bring new relational possibilities into view