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Institution

University of Colorado Colorado Springs

EducationColorado Springs, Colorado, United States
About: University of Colorado Colorado Springs is a education organization based out in Colorado Springs, Colorado, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 6664 authors who have published 10872 publications receiving 323416 citations. The organization is also known as: UCCS & University of Colorado at Colorado Springs.


Papers
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Journal ArticleDOI
TL;DR: Experimental results on representative server workloads show that STFC outperforms popular controllers such as Kalman filter, ARMA and, Adaptive PI in the control of CPU, memory, and disk bandwidth resources under both static and dynamic workloads.
Abstract: Cloud elasticity allows dynamic resource provisioning in concert with actual application demands. Feedback control approaches have been applied with success to resource allocation in physical servers. However, cloud dynamics make the design of an accurate and stable resource controller challenging, especially when application-level performance is considered as the measured output. Application-level performance is highly dependent on the characteristics of workload and sensitive to cloud dynamics. To address these challenges, we extend a self-tuning fuzzy control (STFC) approach, originally developed for response time assurance in web servers to resource allocation in virtualized environments. We introduce mechanisms for adaptive output amplification and flexible rule selection in the STFC approach for better adaptability and stability. Based on the STFC, we further design a two-layer QoS provisioning framework, DynaQoS, that supports adaptive multi-objective resource allocation and service differentiation. We implement a prototype of DynaQoS on a Xen-based cloud testbed. Experimental results on representative server workloads show that STFC outperforms popular controllers such as Kalman filter, ARMA and, Adaptive PI in the control of CPU, memory, and disk bandwidth resources under both static and dynamic workloads. Further results with multiple control objectives and service classes demonstrate the effectiveness of DynaQoS in performance-power control and service differentiation.

77 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigate if leaf hydrophobicity and water droplet retention are additional influences on canopy storage capacity and test the hypothesis that species with the highest leaf hydophobicity had the lowest canopy storage capability on per leaf area basis.
Abstract: Canopy storage capacity is influenced by several variables, including canopy surface area, canopy architecture, and wind. Different species with the same canopy area, but with differences in leaf hydrophobicity and water droplet retention, may produce different values of canopy storage capacity. The objective of this study was to investigate if leaf hydrophobicity and water droplet retention are additional influences on canopy storage capacity. Specifically, this study tested the hypothesis that species with the highest leaf hydrophobicity and the lowest water droplet retention had the lowest canopy storage capacity on a per leaf area basis. Seven tree species from Colorado, United States were selected for experimentation. Five branches from each species were lopped, positioned under a rainfall simulator, and connected to a balance to record the mass gain of the branches by rainfall interception during 17 min of rainfall simulation. Each branch was destructively sampled following rainfall simulation to calculate the leaf and woody surface areas. The rank order of leaf surface storages at canopy storage capacity for each species corresponded to the rank order of leaf hydrophobicity and water droplet retention for each species. Species with the highest leaf surface storage had the lowest leaf hydrophobicity and the lowest water droplet retention. The significance of leaf hydrophobicity and water droplet retention as variables that influence canopy storage capacity is a largely unexplored topic in ecohydrology. Copyright © 2012 John Wiley & Sons, Ltd.

77 citations

Journal ArticleDOI
21 Aug 2015-PLOS ONE
TL;DR: This study provides the first examination of terse message retransmission of official warning messages in response to a domestic terrorist attack, the Boston Marathon Bombing in 2013, using messages posted from public officials’ Twitter accounts and employs a negative binomial model to examine how message characteristics affect messageretransmission.
Abstract: Message retransmission is a central aspect of information diffusion. In a disaster context, the passing on of official warning messages by members of the public also serves as a behavioral indicator of message salience, suggesting that particular messages are (or are not) perceived by the public to be both noteworthy and valuable enough to share with others. This study provides the first examination of terse message retransmission of official warning messages in response to a domestic terrorist attack, the Boston Marathon Bombing in 2013. Using messages posted from public officials’ Twitter accounts that were active during the period of the Boston Marathon bombing and manhunt, we examine the features of messages that are associated with their retransmission. We focus on message content, style, and structure, as well as the networked relationships of message senders to answer the question: what characteristics of a terse message sent under conditions of imminent threat predict its retransmission among members of the public? We employ a negative binomial model to examine how message characteristics affect message retransmission. We find that, rather than any single effect dominating the process, retransmission of official Tweets during the Boston bombing response was jointly influenced by various message content, style, and sender characteristics. These findings suggest the need for more work that investigates impact of multiple factors on the allocation of attention and on message retransmission during hazard events.

77 citations

Proceedings ArticleDOI
13 Nov 2014
TL;DR: In this article, a modular approach based on distributed continuous cell-level control is presented that extends the balancing function to higher level pack performance objectives such as improving power capability and increasing pack lifetime.
Abstract: Energy storage systems require battery cell balancing circuits to avoid divergence of cell state of charge (SOC). A modular approach based on distributed continuous cell-level control is presented that extends the balancing function to higher level pack performance objectives such as improving power capability and increasing pack lifetime. This is achieved by adding DC-DC converters in parallel with cells and using state estimation and control to autonomously bias individual cell SOC and SOC range, forcing healthier cells to be cycled deeper than weaker cells. The result is a pack with improved degradation characteristics and extended lifetime. The modular architecture and control concepts are developed and hardware results are demonstrated for a 91.2 Wh battery pack consisting of four series li-ion battery cells and four dual active bridge (DAB) bypass DC-DC converters.

77 citations

Patent
02 Jul 1987
TL;DR: In this article, a transpolarizer is employed as a programmable capacitance divider, where two ferroelectric capacitors are coupled in series to form a common node and two extreme poles, and a voltage develops at the common node which is above or below the midpoint between VSS and VCC, and will be indicative of the stored data.
Abstract: A transpolarizer is employed as a programmable capacitance divider. Two ferroelectric capacitors are coupled in series to form a common node and two extreme poles. The polarization of the two capacitors is set by grounding the two poles and then bringing them both up to VCC while impressing a voltage at the common node corresponding to data to be stored. Later, while one pole is held at VSS, the other pole is pulsed from VSS to VCC with the common node floating. A voltage develops at the common node which is above or below the midpoint between VSS and VCC, and will be indicative of the stored data. The capacitance divider is programmed in accordance with data. One such divider is added to a DRAM memory cell to form a shadow DRAM cell. Two such dividers are added to a static RAM memory cell to form a shadow static RAM cell. The same divider arrangement is operable in both volatile and non-volatile modes. An improvement arises by using PZT as dielectric in 54:46 mole ratio.

77 citations


Authors

Showing all 6706 results

NameH-indexPapersCitations
Jeff Greenberg10554243600
James F. Scott9971458515
Martin Wikelski8942025821
Neil W. Kowall8927934943
Ananth Dodabalapur8539427246
Tom Pyszczynski8224630590
Patrick S. Kamath7846631281
Connie M. Weaver7747330985
Alejandro Lucia7568023967
Michael J. McKenna7035616227
Timothy J. Craig6945818340
Sheldon Solomon6715023916
Michael H. Stone6537016355
Christopher J. Gostout6533413593
Edward T. Ryan6030311822
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202325
202246
2021568
2020543
2019479
2018454