More Like this

1. Branch-Pipe: Improving Graph Skeletonization around Branch Points in 3D Point Clouds

   https://doi.org/10.3390/rs13193802  

   Ziamtsov, Illia ; Faizi, Kian ; Navlakha, Saket ( September 2021 , Remote sensing)

   Modern plant phenotyping requires tools that are robust to noise and missing data, while being able to efficiently process large numbers of plants. Here, we studied the skeletonization of plant architectures from 3D point clouds, which is critical for many downstream tasks, including analyses of plant shape, morphology, and branching angles. Specifically, we developed an algorithm to improve skeletonization at branch points (forks) by leveraging the geometric properties of cylinders around branch points. We tested this algorithm on a diverse set of high-resolution 3D point clouds of tomato and tobacco plants, grown in five environments and across multiple developmental timepoints. Compared to existing methods for 3D skeletonization, our method efficiently and more accurately estimated branching angles even in areas with noisy, missing, or non-uniformly sampled data. Our method is also applicable to inorganic datasets, such as scans of industrial pipes or urban scenes containing networks of complex cylindrical shapes. 

   more » « less
2. To preserve, release, and litigate: Dimensions of executive branch transparency

   https://doi.org/10.1111/psq.12824  

   Johnson, Gbemende E. ; George, Tracey E. ( June 2023 , Presidential Studies Quarterly)

   Douglas Kriner (Ed.)

   Transparency is essential for public awareness of government activity and in holding officials accountable for their behavior and decisions. However, executives understandably have a desire to maintain autonomy over the flow of information outside of the executive branch, which can sometimes lead to a clash between government openness and executive control over information. This article investigates executive branch transparency along two specific dimensions: threats to the preservation of government information, and the judicial monitoring of executive branch transparency. Federal law directs executive branch actors to preserve government information. Statutes and regulations detail governing policies as well as guidelines that apply to every presidential administration. However, we consider each rule and recommendation through the lens of the Trump administration to gain greater clarity and precision. The Trump administration proves a useful focus for our empirical analysis because of its recency as well as multiple reports of its improper handling and preservation of records. We lay out and develop a typology of threats to record preservation. Preservation conflicts have emerged across multiple presidential administrations and have become increasingly common and visible. Judicial monitoring of executive branch transparency has become a crucial tool to address the withholding of records. We show that federal judges can play a vital role in defining the boundaries of government transparency through their decisions in Freedom of Information Act (FOIA) litigation. The U.S. Department of Justice oversees and often leads the government's defense against FOIA actions. We find that federal judges are most likely to require executive branch responsiveness and disclosure when the judges' underlying policy preferences are most distant from that of the administration. Our findings should inform reforms to protect government transparency.

    

   more » « less
3. Isolation branching: a branch and bound algorithm for the k-terminal cut problem

   https://doi.org/10.1007/s10878-020-00534-y  

   Velednitsky, Mark ; Hochbaum, Dorit S. ( February 2020 , Journal of Combinatorial Optimization)
4. Short branch cut approximation in two-dimensional hydrodynamics with free surface

   https://doi.org/10.1098/rspa.2020.0811  

   Dyachenko, A. I. ; Dyachenko, S. A. ; Lushnikov, P. M. ; Zakharov, V. E. ( May 2021 , Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences)

   null (Ed.)

   A potential motion of ideal incompressible fluid with a free surface and infinite depth is considered in two-dimensional geometry. A time-dependent conformal mapping of the lower complex half-plane of the auxiliary complex variable w into the area filled with fluid is performed with the real line of w mapped into the free fluid’s surface. The fluid dynamics can be fully characterized by the motion of the complex singularities in the analytical continuation of both the conformal mapping and the complex velocity. We consider the short branch cut approximation of the dynamics with the small parameter being the ratio of the length of the branch cut to the distance between its centre and the real line of w . We found that the fluid dynamics in that approximation is reduced to the complex Hopf equation for the complex velocity coupled with the complex transport equation for the conformal mapping. These equations are fully integrable by characteristics producing the infinite family of solutions, including moving square root branch points and poles. These solutions involve practical initial conditions resulting in jets and overturning waves. The solutions are compared with the simulations of the fully nonlinear Eulerian dynamics giving excellent agreement even when the small parameter approaches about one. 

   more » « less
5. Left branch extraction, object shift, and freezing effects in Tumbalá Ch’ol

   https://doi.org/10.5334/gjgl.988  

   Little, Carol-Rose ( January 2020 , Glossa: a journal of general linguistics)