Normalizing Flow Ensembles for Rich Aleatoric and Epistemic Uncertainty Modeling

In this work, we demonstrate how to reliably estimate epistemic uncertainty while maintaining the flexibility needed to capture complicated aleatoric distributions. To this end, we propose an ensemble of Normalizing Flows (NF), which are state-of-the-art in modeling aleatoric uncertainty. The ensembles are created via sets of fixed dropout masks, making them less expensive than creating separate NF models. We demonstrate how to leverage the unique structure of NFs, base distributions, to estimate aleatoric uncertainty without relying on samples, provide a comprehensive set of baselines, and derive unbiased estimates for differential entropy. The methods were applied to a variety of experiments, commonly used to benchmark aleatoric and epistemic uncertainty estimation: 1D sinusoidal data, 2D windy grid-world ($\it{Wet Chicken}$), $\it{Pendulum}$, and $\it{Hopper}$. In these experiments, we setup an active learning framework and evaluate each model's capability at measuring aleatoric and epistemic uncertainty. The results show the advantages of using NF ensembles in capturing complicated aleatoric while maintaining accurate epistemic uncertainty estimates

SB22-10/11: COT West Campus

SB22-10/11: COT West Campus. This resolution passed unanimously during the March 9, 2011 meeting of the Associated Students of the University of Montana (ASUM)

Circumscribed choroidal hemangioma: A case report and literature review

AbstractChoroidal hemangioma is a rare congenital ocular tumor that can present as either circumscribed or diffuse. Circumscribed choroidal hemangioma (CCH) typically manifests as a red-orange mass within the posterior pole and appears similar to other ocular conditions, such as choroidal melanoma and choroidal metastasis. Proper diagnosis is crucial and is aided by the use of ancillary testing. CCH itself is benign but can cause secondary complications such as subretinal fluid accumulation and subsequent retinal detachment. If these conditions should arise, several treatment options are available

Circumscribed choroidal hemangioma: A case report and literature review

AbstractChoroidal hemangioma is a rare congenital ocular tumor that can present as either circumscribed or diffuse. Circumscribed choroidal hemangioma (CCH) typically manifests as a red-orange mass within the posterior pole and appears similar to other ocular conditions, such as choroidal melanoma and choroidal metastasis. Proper diagnosis is crucial and is aided by the use of ancillary testing. CCH itself is benign but can cause secondary complications such as subretinal fluid accumulation and subsequent retinal detachment. If these conditions should arise, several treatment options are available

Monitoring Salish Sea bull kelp (Nereocystis luetkeana) via kayak surveys

Conspicuous declines in the abundance of bull kelp (Nereocystis luetkeana), the most common canopy-forming species in Puget Sound, have been observed in many areas. Despite these observations, little information on abundance, or temporal changes in kelp distribution have been scientifically documented. To document and increase attention to changes in kelp populations around the region, the Northwest Straits Initiative formed a Salish Sea International Kelp Alliance and developed a scientifically-driven monitoring protocol. Citizen scientists of the Northwest Straits Marine Resources Committees then applied the protocol to delineate kelp beds via kayak over the summers of 2015-2107. The protocol has now been added to the Washington State Puget Sound Estuarine Monitoring Program PSEMP Nearshore Monitoring Toolbox and is very similar to protocols used by citizen science groups in the Gulf Islands of British Columbia. This presentation provides a summary of results on changes in extent observed throughout summer months, as well as, changes observed over the 3 years of sampling. To date, more than 177 Bull kelp kayak surveys, at 42 sites, have been acquired in 7 counties of the Northwest Straits over 3 summers. Fourteen of the sites have a full 3 years of data on presence/absence, acreage and ancillary measurements of depth and temperature. Data will be made available from the Northwest Straits online mapping application SoundIQ linked to interactive maps, data, photos and summary results in Storymap format

Hybrid Hidden Markov Model and Generalized Linear Model for Auto Insurance Premiums

We describe a new approach to estimate the pure premium for automobile insurance. Using the theory of hidden Markov models (HMM) we derive a Poisson-gamma HMM and a hybrid between HMMs and generalized linear models (HMM-GLM). The hidden state is meant to represent a driver's skill thus capturing an unseen variable. The Poisson-gamma HMM and HMM-GLM have two emissions, severity and claim count, making it easier to compare to current actuarial models. The proposed models help deal with the overdispersion problem in claim counts and introduces dependence between the severity and claim count. We derive maximum likelihood estimates for the parameters of the proposed models and then using simulations with the Expectation Maximization algorithm we compare the three methods: GLMs, HMMs and HMM-GLMs. We show that in some instances the HMM-GLM outperforms the standard GLM, while the Poisson-gamma HMM under-performs the other models. Thus in certain situations it may be worth the added complexity of a HMM-GLM

Phase transition in a stochastic prime number generator

We introduce a stochastic algorithm that acts as a prime number generator. The dynamics of such algorithm gives rise to a continuous phase transition which separates a phase where the algorithm is able to reduce a whole set of integers into primes and a phase where the system reaches a frozen state with low prime density. We present both numerical simulations and an analytical approach in terms of an annealed approximation, by means of which the data are collapsed. A critical slowing down phenomenon is also outlined.Comment: accepted in PRE (Rapid Comm.

Towards an embedding of Graph Transformation in Intuitionistic Linear Logic

Linear logics have been shown to be able to embed both rewriting-based approaches and process calculi in a single, declarative framework. In this paper we are exploring the embedding of double-pushout graph transformations into quantified linear logic, leading to a Curry-Howard style isomorphism between graphs and transformations on one hand, formulas and proof terms on the other. With linear implication representing rules and reachability of graphs, and the tensor modelling parallel composition of graphs and transformations, we obtain a language able to encode graph transformation systems and their computations as well as reason about their properties