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Wyatt Pochman

Publications and source records attributed to Wyatt Pochman.

3 recordsLinked to original sources

Structural and Temporal Hallmarks of Genealogical Networks

The rapid growth of the genealogical sector, spanning platforms with billions of records and millions of users, has produced some of the largest and most complex networks available for analysis. Despite substantial advances in genealogical network research, it remains unclear whether human kinship networks exhibit universal structural properties. We address this by developing an integrated approach to genealogical network analysis that combines network-theoretic structure with an inferred notion of time. Using over one hundred datasets from the Kinsources repository, we reinterpret standard network measures in genealogical terms and introduce \emph{pseudogenerations}, a method for extracting temporal structure directly from network topology. Within this framework, we identify common features shared across datasets. We find that genealogical networks exhibit scale-free--like degree and component-size distributions, multiscale family organization, and small-world behavior with respect to genetic and union-based distances. We show that 2-components provide a natural unit of genealogical structure, observe consistent disassortative mixing, and find that recorded unions are strongly biased toward short genetic distances relative to potential pairings. We also document temporal and demographic patterns, including shifts in recorded parental and child information, as well as correlations among recorded unions, parents, and children. These results suggest that diverse genealogical datasets share a common set of structural and temporal characteristics, providing evidence for universal features of human kinship networks and establishing a general framework for their comparative analysis.

cs.SI

Optimal Control Strategies for Multi-Agent Sheep Herding

We develop a cost functional and state-space equations to model the problem of herding m sheep to the origin using n dogs. Our initial approach uses solve_bvp to approximate optimal control trajectories. But this method often fails to converge due to the system's high dimensionality and nonlinearity. However, with a well-chosen initial guess and carefully selected hyperparameters, we succeed in getting solve_bvp to converge. We also explore alternatives including the shooting method and linearization with the iterative Linear Quadratic Regulator (iLQR). While the shooting method also suffers from poor convergence, the linearized iLQR approach proves more scalable and successfully handles scenarios with more agents. However, it struggles in regions where dogs and sheep are in close proximity, due to strong nonlinearities that violate the assumptions of local linearization. This leads to jagged, oscillatory paths and slow convergence, particularly when the number of sheep exceeds the number of dogs. These challenges reveal key limitations of standard numerical techniques in multi-agent control and underscore the need for more robust, nonlinear strategies for coordinating interacting agents.

math.OC

Explorations of Epidemiological Dynamics across Multiple Population Hubs

Understanding the dynamics of the spread of diseases within populations is critical for effective public health interventions. We extend the classical SIR model by incorporating additional complexities such as the introduction of a cure and migration between cities. Our framework leverages a system of differential equations to simulate disease transmission across a network of interconnected cities, capturing more realistic patterns. We present theoretical results on the convergence of population sizes in the migration framework (in the absence of deaths). We also run numerical simulations to understand how the timing of the introduction of the cure affects mortality rates. Our numerical results explain how localized interventions affect the spread of the disease across cities. In summary, this work advances the modeling of epidemics to a more local scope, offering a more expressive tool for epidemiological research and public health planning.

q-bio.PE