23 research outputs found
A Haptics Symposium Retrospective: 20 Years
The very first "Haptics Symposium" actually went by the name "Issues in the Development of Kinesthetic Displays of Teleoperation and Virtual environments." The word "Haptic" didn't make it into the name until the next year. Not only was the most important word absent but so were RFPs, journals and commercial markets. And yet, as we prepare for the 2012 symposium, haptics is a thriving and amazingly diverse field of endeavor. In this talk we'll reflect on the origins of this field and on its evolution over the past twenty years, as well as the evolution of the Haptics Symposium itself. We hope to share with you some of the excitement we've felt along the way, and that we continue to feel as we look toward the future of our field
A Heat Diffusion Perspective on Geodesic Preserving Dimensionality Reduction
Diffusion-based manifold learning methods have proven useful in
representation learning and dimensionality reduction of modern high
dimensional, high throughput, noisy datasets. Such datasets are especially
present in fields like biology and physics. While it is thought that these
methods preserve underlying manifold structure of data by learning a proxy for
geodesic distances, no specific theoretical links have been established. Here,
we establish such a link via results in Riemannian geometry explicitly
connecting heat diffusion to manifold distances. In this process, we also
formulate a more general heat kernel based manifold embedding method that we
call heat geodesic embeddings. This novel perspective makes clearer the choices
available in manifold learning and denoising. Results show that our method
outperforms existing state of the art in preserving ground truth manifold
distances, and preserving cluster structure in toy datasets. We also showcase
our method on single cell RNA-sequencing datasets with both continuum and
cluster structure, where our method enables interpolation of withheld
timepoints of data. Finally, we show that parameters of our more general method
can be configured to give results similar to PHATE (a state-of-the-art
diffusion based manifold learning method) as well as SNE (an
attraction/repulsion neighborhood based method that forms the basis of t-SNE).Comment: 31 pages, 13 figures, 10 table
BLIS-Net: Classifying and Analyzing Signals on Graphs
Graph neural networks (GNNs) have emerged as a powerful tool for tasks such
as node classification and graph classification. However, much less work has
been done on signal classification, where the data consists of many functions
(referred to as signals) defined on the vertices of a single graph. These tasks
require networks designed differently from those designed for traditional GNN
tasks. Indeed, traditional GNNs rely on localized low-pass filters, and signals
of interest may have intricate multi-frequency behavior and exhibit long range
interactions. This motivates us to introduce the BLIS-Net (Bi-Lipschitz
Scattering Net), a novel GNN that builds on the previously introduced geometric
scattering transform. Our network is able to capture both local and global
signal structure and is able to capture both low-frequency and high-frequency
information. We make several crucial changes to the original geometric
scattering architecture which we prove increase the ability of our network to
capture information about the input signal and show that BLIS-Net achieves
superior performance on both synthetic and real-world data sets based on
traffic flow and fMRI data
Ernst Freund as Precursor of the Rational Study of Corporate Law
Gindis, David, Ernst Freund as Precursor of the Rational Study of Corporate Law (October 27, 2017). Journal of Institutional Economics, Forthcoming. Available at SSRN: https://ssrn.com/abstract=2905547, doi: https://dx.doi.org/10.2139/ssrn.2905547The rise of large business corporations in the late 19th century compelled many American observers to admit that the nature of the corporation had yet to be understood. Published in this context, Ernst Freund's little-known The Legal Nature of Corporations (1897) was an original attempt to come to terms with a new legal and economic reality. But it can also be described, to paraphrase Oliver Wendell Holmes, as the earliest example of the rational study of corporate law. The paper shows that Freund had the intuitions of an institutional economist, and engaged in what today would be called comparative institutional analysis. Remarkably, his argument that the corporate form secures property against insider defection and against outsiders anticipated recent work on entity shielding and capital lock-in, and can be read as an early contribution to what today would be called the theory of the firm.Peer reviewe
The comparison of different wetland fish assemblages over time
Wetlands provide essential ecosystem services. Historically, we have drained and filled 73% of wetlands for agricultural use throughout the United States from the 1780s to the 1980s (Dahl, 1990). A nationwide focus on restoring wetlands has since occurred. Literature on restored/mitigated wetlands is rife with examples that do and do not support the same ecosystem services as natural wetlands (Langston, 1997; Meil, 2014). Restoration of wetlands occurred at the Green Bottom Wildlife Management Area (GBWMA) over several decades. Various sections of the wetland were classified by age, water depth, and vegetation. One hypothesis was that differences in fish assemblage would be observed based on the age of wetland assemblage. Fishes were sampled using Hoop nets in five wetland areas using proportional randomized sampling locations. Each location was sampled multiple times from March–May of 2023. We compared sampling efforts to find an efficient method for study replication. We also used Nonmetric Multidimensional Scaling (NMS) to see if an overlap in species composition was present between various sites. Differences between fish assemblages were driven by age, water depth, and habitat types. Sites that were similar in age and water depth had similar fish assemblages. Species specific growth rates were calculated to compare the health of different fish assemblages
'the Vicar Of Wakefield': Its Relationship To The Eighteenth Century Novel.
PhDLiteratureUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/182115/2/5807674.pd