110,100 research outputs found
On Two Ways of Enumerating Ordered Trees
The middle-levels graph () has a dihedral quotient
pseudograph whose vertices are the -edge ordered trees , each
encoded as a -string formed via DFS by: {\bf(i)}
(BFS-assigned) Kierstead-Trotter lexical colors for
the descending nodes; {\bf(ii)} asterisks for the ascending edges. Two
ways of corresponding a restricted-growth -string to each
exist, namely one Stanley's way and a novel way that assigns to
via nested substring-swaps. These swaps permit to sort as an ordered
tree that allows a lexical visualization of as well as the Hamilton
cycles of constructed by P. Gregor, T. M\"utze and J. Nummenpalo.Comment: 26 pages, 8 figures, 10 table
TreeWatch.net : a water and carbon monitoring and modeling network to assess instant tree hydraulics and carbon status
TreeWatch.net is an initiative that has been developed to watch trees grow and function in real-time. It is a water- and carbon-monitoring and modeling network, in which high quality measurements of sap flow and stem diameter variation are collected on individual trees. Automated data processing using a cloud service enables instant visualization of water movement and radial stem growth. This can be used to demonstrate the sensitivity of trees to changing weather conditions, such as drought, heat waves, or heavy rain showers. But TreeWatch.net's true innovation lies in its use of these high precision harmonized data to also parameterize process-based tree models in real-time, which makes displaying the much needed mechanisms underlying tree responses to climate change possible. Continuous simulation of turgor to describe growth processes and long-term time series of hydraulic resistance to assess drought-vulnerability in real-time are only a few of the opportunities our approach offers. TreeWatch.net has been developed with the view to be complementary to existing forest monitoring networks and with the aim to contribute to existing dynamic global vegetation models. It provides high-quality data and real-time simulations in order to advance research on the impact of climate change on the biological response of trees and forests. Besides its application in natural forests to answer climate-change related scientific and political questions, we also envision a broader societal application of TreeWatch.net by selecting trees in nature reserves, public areas, cities, university areas, schoolyards, and parks to teach youngsters and create public awareness on the effects of changing weather conditions on trees and forests in this era of climate change
Task-based Augmented Contour Trees with Fibonacci Heaps
This paper presents a new algorithm for the fast, shared memory, multi-core
computation of augmented contour trees on triangulations. In contrast to most
existing parallel algorithms our technique computes augmented trees, enabling
the full extent of contour tree based applications including data segmentation.
Our approach completely revisits the traditional, sequential contour tree
algorithm to re-formulate all the steps of the computation as a set of
independent local tasks. This includes a new computation procedure based on
Fibonacci heaps for the join and split trees, two intermediate data structures
used to compute the contour tree, whose constructions are efficiently carried
out concurrently thanks to the dynamic scheduling of task parallelism. We also
introduce a new parallel algorithm for the combination of these two trees into
the output global contour tree. Overall, this results in superior time
performance in practice, both in sequential and in parallel thanks to the
OpenMP task runtime. We report performance numbers that compare our approach to
reference sequential and multi-threaded implementations for the computation of
augmented merge and contour trees. These experiments demonstrate the run-time
efficiency of our approach and its scalability on common workstations. We
demonstrate the utility of our approach in data segmentation applications
Mapping the Curricular Structure and Contents of Network Science Courses
As network science has matured as an established field of research, there are
already a number of courses on this topic developed and offered at various
higher education institutions, often at postgraduate levels. In those courses,
instructors adopted different approaches with different focus areas and
curricular designs. We collected information about 30 existing network science
courses from various online sources, and analyzed the contents of their syllabi
or course schedules. The topics and their curricular sequences were extracted
from the course syllabi/schedules and represented as a directed weighted graph,
which we call the topic network. Community detection in the topic network
revealed seven topic clusters, which matched reasonably with the concept list
previously generated by students and educators through the Network Literacy
initiative. The minimum spanning tree of the topic network revealed typical
flows of curricular contents, starting with examples of networks, moving onto
random networks and small-world networks, then branching off to various
subtopics from there. These results illustrate the current state of consensus
formation (including variations and disagreements) among the network science
community on what should be taught about networks and how, which may also be
informative for K--12 education and informal education.Comment: 17 pages, 11 figures, 2 tables; to appear in Cramer, C. et al.
(eds.), Network Science in Education -- Tools and Techniques for Transforming
Teaching and Learning (Springer, 2017, in press
Using the forest vegetation simulator as a teaching tool
The Forest Vegetation Simulator (FVS) is a tree-level, spatially non-explicit growth model. It is an outgrowth of the Stand Prognosis model that the U.S. Forest Service began developing in the late 1960s. Local variants of FVS now cover most of the forest types of the United States. Development of two complementary programs, Suppose and the Stand Visualization System (SVS), have opened the possibilities for using FVS as a teaching tool in forestry classes
A visual analysis of the usage efficiency of library books
The monographic collections in academic libraries have undergone a period of tremendous growth in volume, in subject diversity, and in formats during the recent several decades. Readers may find it difficult to prioritize which book(s) should be borrowed for a specific purpose. The log data of book loan record may serve as a visible indicator for the more sought-after books by the readers. This paper describes our experimental efforts in works in a university library setting. The visual analysis is thought to provide an effective way to extract the book usage information, which may yield new insights into a host of other related technical as well as user behavior issues. Initial experiment has demonstrated that the proposed approach as articulated in this article can actually benefit end-users as well as library collection development personnel in their endeavor of book selections with effective measure.</p
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