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Institution

Texas A&M University

EducationCollege Station, Texas, United States
About: Texas A&M University is a education organization based out in College Station, Texas, United States. It is known for research contribution in the topics: Population & Finite element method. The organization has 72169 authors who have published 164372 publications receiving 5764236 citations.


Papers
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Proceedings Article
05 Jul 2011
TL;DR: It is found that LSS users follow the “Levy Flight” mobility pattern and adopt periodic behaviors; while geographic and economic constraints affect mobility patterns, so does individual social status; and Content and sentiment-based analysis of posts associated with checkins can provide a rich source of context for better understanding how users engage with these services.
Abstract: Location sharing services (LSS) like Foursquare, Gowalla, and Facebook Places support hundreds of millions of user-driven footprints (i.e., "checkins"). Those global-scale footprints provide a unique opportunity to study the social and temporal characteristics of how people use these services and to model patterns of human mobility, which are significant factors for the design of future mobile+location-based services, traffic forecasting, urban planning, as well as epidemiological models of disease spread. In this paper, we investigate 22 million checkins across 220,000 users and report a quantitative assessment of human mobility patterns by analyzing the spatial, temporal, social, and textual aspects associated with these footprints. We find that: (i) LSS users follow the “Levy Flight” mobility pattern and adopt periodic behaviors; (ii) While geographic and economic constraints affect mobility patterns, so does individual social status; and (iii) Content and sentiment-based analysis of posts associated with checkins can provide a rich source of context for better understanding how users engage with these services.

742 citations

Book
14 Dec 2011
TL;DR: This book has three intended uses: a classroom textbook, a reference work for researchers in the sciences, and an account of classical and modern results in (aspects of) the theory that will be of interest to researchers in geometry.
Abstract: Tensors are ubiquitous in the sciences. The geometry of tensors is both a powerful tool for extracting information from data sets, and a beautiful subject in its own right. This book has three intended uses: a classroom textbook, a reference work for researchers in the sciences, and an account of classical and modern results in (aspects of) the theory that will be of interest to researchers in geometry. For classroom use, there is a modern introduction to multilinear algebra and to the geometry and representation theory needed to study tensors, including a large number of exercises. For researchers in the sciences, there is information on tensors in table format for easy reference and a summary of the state of the art in elementary language. This is the first book containing many classical results regarding tensors. Particular applications treated in the book include the complexity of matrix multiplication, $\mathbf{P}$ versus $\mathbf{NP}$, signal processing, phylogenetics, and algebraic statistics. For geometers, there is material on secant varieties, $G$-varieties, spaces with finitely many orbits and how these objects arise in applications, discussions of numerous open questions in geometry arising in applications, and expositions of advanced topics such as the proof of the Alexander-Hirschowitz theorem and of the Weyman-Kempf method for computing syzygies.

742 citations

Journal ArticleDOI
TL;DR: Simulation results show that the proposed spectrum sensing schemes can considerably improve system performance, and useful principles for the design of distributed wideband spectrum sensing algorithms in cognitive radio networks are established.
Abstract: Spectrum sensing is an essential functionality that enables cognitive radios to detect spectral holes and to opportunistically use under-utilized frequency bands without causing harmful interference to legacy (primary) networks. In this paper, a novel wideband spectrum sensing technique referred to as multiband joint detection is introduced, which jointly detects the primary signals over multiple frequency bands rather than over one band at a time. Specifically, the spectrum sensing problem is formulated as a class of optimization problems, which maximize the aggregated opportunistic throughput of a cognitive radio system under some constraints on the interference to the primary users. By exploiting the hidden convexity in the seemingly nonconvex problems, optimal solutions can be obtained for multiband joint detection under practical conditions. The situation in which individual cognitive radios might not be able to reliably detect weak primary signals due to channel fading/shadowing is also considered. To address this issue by exploiting the spatial diversity, a cooperative wideband spectrum sensing scheme refereed to as spatial-spectral joint detection is proposed, which is based on a linear combination of the local statistics from multiple spatially distributed cognitive radios. The cooperative sensing problem is also mapped into an optimization problem, for which suboptimal solutions can be obtained through mathematical transformation under conditions of practical interest. Simulation results show that the proposed spectrum sensing schemes can considerably improve system performance. This paper establishes useful principles for the design of distributed wideband spectrum sensing algorithms in cognitive radio networks.

742 citations

Journal ArticleDOI
TL;DR: The most reliable approach for discriminating bacterial versus thermochemical sulfate reduction is to combine as many of these criteria as possible as mentioned in this paper, which can be used in exploration or deposits of hydrocarbons, sour gas, elemental sulfur, and certain metal sulfides.

741 citations

Journal ArticleDOI
TL;DR: In soybean leaves that had been dehydrated to cause a 15% decrease in fresh weight, JA levels increased approximately 5-fold within 2 h and declined to approximately control levels by 4 h and a lag time of 1-2 h occurred before abscisic acid accumulation reached a maximum.
Abstract: Jasmonic acid (JA) is a naturally occurring growth regulator found in higher plants. Several physiological roles have been described for this compound (or a related compound, methyl jasmonate) during plant development and in response to biotic and abiotic stress. To accurately determine JA levels in plant tissue, we have synthesized JA containing 13C for use as an internal standard with an isotopic composition of [225]:[224] 0.98:0.02 compared with [225]:[224] 0.15:0.85 for natural material. GC analysis (flame ionization detection and MS) indicate that the internal standard is composed of 92% 2-(+/-)-[13C]JA and 8% 2-(+/-)-7-iso-[13C]JA. In soybean plants, JA levels were highest in young leaves, flowers, and fruit (highest in the pericarp). In soybean seeds and seedlings, JA levels were highest in the youngest organs including the hypocotyl hook, plumule, and 12-h axis. In soybean leaves that had been dehydrated to cause a 15% decrease in fresh weight, JA levels increased approximately 5-fold within 2 h and declined to approximately control levels by 4 h. In contrast, a lag time of 1-2 h occurred before abscisic acid accumulation reached a maximum. These results will be discussed in the context of multiple pathways for JA biosynthesis and the role of JA in plant development and responses to environmental signals.

741 citations


Authors

Showing all 72708 results

NameH-indexPapersCitations
Yi Chen2174342293080
Scott M. Grundy187841231821
Evan E. Eichler170567150409
Yang Yang1642704144071
Martin Karplus163831138492
Robert Stone1601756167901
Philip Cohen154555110856
Claude Bouchard1531076115307
Jongmin Lee1502257134772
Zhenwei Yang150956109344
Vivek Sharma1503030136228
Frede Blaabjerg1472161112017
Steven L. Salzberg147407231756
Mikhail D. Lukin14660681034
John F. Hartwig14571466472
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20241
2023211
2022938
20218,664
20208,925
20198,426