98,262 research outputs found
Joshua Davis: Author of Spare Parts
No full textCitation: K-State First (2016). Joshua Davis: Author of Spare Parts [Flier]. Manhattan, Kansas: K-State First.Flyer advertising Joshua Davis's author talk at Kansas State University
Epic Fail: Emulators Can Tolerate Polynomially Many Edge Faults for Free
No full textA t-emulator of a graph G is a graph H that approximates its pairwise shortest path distances up to multiplicative t error. We study fault tolerant t-emulators, under the model recently introduced by Bodwin, Dinitz, and Nazari [ITCS 2022] for vertex failures. In this paper we consider the version for edge failures, and show that they exhibit surprisingly different behavior.
In particular, our main result is that, for (2k-1)-emulators with k odd, we can tolerate a polynomial number of edge faults for free. For example: for any n-node input graph, we construct a 5-emulator (k = 3) on O(n^{4/3}) edges that is robust to f = O(n^{2/9}) edge faults. It is well known that Ω(n^{4/3}) edges are necessary even if the 5-emulator does not need to tolerate any faults. Thus we pay no extra cost in the size to gain this fault tolerance. We leave open the precise range of free fault tolerance for odd k, and whether a similar phenomenon can be proved for even k
Steven Johnson Author Talk Poster
No full textK-State Book NetworkA poster advertising an author talk by Steven Johnson at Kansas State University on September 3, 2014. Steven Johnson's book "The Ghost Map" was the 2014-2015 common book
Data for Nazari et al 2023.zip in Cells: doi: 10.3390/cells12202474
No full textData underlying the manuscript "Long prehensile protrusions can facilitate cancer cell invasion through the basement membrane" in the journal Cells by Nazari et al. 2023: doi: 10.3390/cells12202474</p
Near-Optimal Decremental Hopsets with Applications
No full textGiven a weighted undirected graph , a hopset of hopbound
and stretch is a set of edges such that for any pair of
nodes , there is a path in of at most hops,
whose length is within a factor from the distance between
and in .
We show the first efficient decremental algorithm for maintaining hopsets
with a polylogarithmic hopbound. The update time of our algorithm matches the
best known static algorithm up to polylogarithmic factors. All the previous
decremental hopset constructions had a superpolylogarithmic (but subpolynomial)
hopbound of [Bernstein, FOCS'09; HKN, FOCS'14;
Chechik, FOCS'18].
By applying our decremental hopset construction, we get improved or near
optimal bounds for several distance problems. Most importantly, we show how to
decrementally maintain -approximate all-pairs shortest
paths (for any constant , in amortized update
time and query time. This improves (by a polynomial factor) over the
update-time of the best previously known decremental algorithm in the constant
query time regime. Moreover, it improves over the result of [Chechik, FOCS'18]
that has a query time of , where is the aspect ratio, and
the amortized update time is
. For sparse
graphs our construction nearly matches the best known static running time /
query time tradeoff.
We also obtain near-optimal bounds for maintaining approximate multi-source
shortest paths and distance sketches, and get improved bounds for approximate
single-source shortest paths. Our algorithms are randomized and our bounds hold
with high probability against an oblivious adversary.Comment: In proceedings of ICALP 2022:
https://drops.dagstuhl.de/opus/volltexte/2022/16427
Stigmaeidae OUDEMANS 1931
No full textFAMILY STIGMAEIDAE OUDEMANS, 1931 Type genus: Stigmaeus Koch, 1836 Stigmaeus Koch, 1836 Type species: Stigmaeus cruentus Koch, 1836Published as part of Nazari, A., Khanjani, M. & Kamali, K., 2012, Two New Eyeless Mite Species From The Western Provinces Of Iran: Stigmaeus Ladanae N. Sp. And Stigmaeus Nasrinae N. Sp. (Acari: Stigmaeidae), pp. 173-181 in Acarologia 52 (2) on page 175, DOI: 10.1051/acarologia/20122047, http://zenodo.org/record/466707
Distributed Distance-Bounded Network Design Through Distributed Convex Programming
No full textSolving linear programs is often a challenging task in distributed settings. While there are good algorithms for solving packing and covering linear programs in a distributed manner (Kuhn et al. 2006), this is essentially the only class of linear programs for which such an algorithm is known. In this work we provide a distributed algorithm for solving a different class of convex programs which we call “distance-bounded network design convex programs”. These can be thought of as relaxations of network design problems in which the connectivity requirement includes a distance constraint (most notably, graph spanners). Our algorithm runs in O((D/ε) log n) rounds in the LOCAL model and with high probability finds a (1+ε)-approximation to the optimal LP solution for any 0 < ε ≤ 1, where D is the largest distance constraint.
While solving linear programs in a distributed setting is interesting in its own right, this class of convex programs is particularly important because solving them is often a crucial step when designing approximation algorithms. Hence we almost immediately obtain new and improved distributed approximation algorithms for a variety of network design problems, including Basic 3- and 4-Spanner, Directed k-Spanner, Lowest Degree k-Spanner, and Shallow-Light Steiner Network Design with a spanning demand graph. Our algorithms do not require any “heavy” computation and essentially match the best-known centralized approximation algorithms, while previous approaches which do not use heavy computation give approximations which are worse than the best-known centralized bounds
Oscillon collapse to black holes
No full textUsing numerical relativity simulations we study the dynamics of pseudo-topological objects called oscillons for a class of models inspired by axion-monodromy. Starting from free field solutions supported by gravitational attractions, we investigate the effect of adding self-interactions, and contrast this with the effect of adding self-interactions whilst removing gravitational support. We map out regions of the parameter space where the initial conditions rapidly collapse to black holes, and other regions where they remain pseudo-stable or disperse
Optimal generation scheduling of large-scale multi-zone combined heat and power systems
No full textCombined heat and power (CHP) technology can simultaneously satisfy heat and power loads. The objective of optimal production scheduling of CHP plants is finding optimal schedule of heat and power plants according to the constraints of network and component. In this research, the solution of CHP economic dispatch (CHPED) in large scale is investigated considering different scenarios. Firstly, the CHPED is tested on a 48-unit system to obtain minimum total operation cost, which includes the operation cost of thermal plants, CHP units and boilers, and the obtained optimal solutions are compared with recent publications. Then, a novel framework for a large-scale multi-zone CHPED problem is introduced, where each zone is responsible of providing the associated heat load. Finally, the multi-objective CHP dispatch problem is studied for handling two competing objectives consisting of operation cost and emissions of pollutant gases. The emission of pollutant gases includes the greenhouse gases emitted by thermal plants, CHP units and boilers. The model is tested on a three-zone 48-unit system for verifying the performance and effectiveness of the model. An annual cost saving of $1,939,534.08 can be attained by using the applied method for the 48-unit CHP system in comparison with the reported results in recent studies
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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