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Universal Framework for Edge Controllability of Complex Network

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Dynamical processes occurring on the edges in complex networks are relevant to a variety of real-world situations. Despite recent advances, a framework for edge controllability is still required for complex networks of arbitrary structure and interaction strength. Generalizing a previously

Dynamical processes occurring on the edges in complex networks are relevant to a variety of real-world situations. Despite recent advances, a framework for edge controllability is still required for complex networks of arbitrary structure and interaction strength. Generalizing a previously introduced class of processes for edge dynamics, the switchboard dynamics, and exploit- ing the exact controllability theory, we develop a universal framework in which the controllability of any node is exclusively determined by its local weighted structure. This framework enables us to identify a unique set of critical nodes for control, to derive analytic formulas and articulate efficient algorithms to determine the exact upper and lower controllability bounds, and to evaluate strongly structural controllability of any given network. Applying our framework to a large number of model and real-world networks, we find that the interaction strength plays a more significant role in edge controllability than the network structure does, due to a vast range between the bounds determined mainly by the interaction strength. Moreover, transcriptional regulatory networks and electronic circuits are much more strongly structurally controllable (SSC) than other types of real-world networks, directed networks are more SSC than undirected networks, and sparse networks are typically more SSC than dense networks.

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2017-06-26

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Universal Formalism of Fano Resonance

Description

The phenomenon of Fano resonance is ubiquitous in a large variety of wave scattering systems, where the resonance profile is typically asymmetric. Whether the parameter characterizing the asymmetry should be complex or real is an issue of great experimental interest.

The phenomenon of Fano resonance is ubiquitous in a large variety of wave scattering systems, where the resonance profile is typically asymmetric. Whether the parameter characterizing the asymmetry should be complex or real is an issue of great experimental interest. Using coherent quantum transport as a paradigm and taking into account of the collective contribution from all available scattering channels, we derive a universal formula for the Fano-resonance profile. We show that our formula bridges naturally the traditional Fano formulas with complex and real asymmetry parameters, indicating that the two types of formulas are fundamentally equivalent (except for an offset). The connection also reveals a clear footprint for the conductance resonance during a dephasing process. Therefore, the emergence of complex asymmetric parameter when fitting with experimental data needs to be properly interpreted. Furthermore, we have provided a theory for the width of the resonance, which relates explicitly the width to the degree of localization of the close-by eigenstates and the corresponding coupling matrices or the self-energies caused by the leads. Our work not only resolves the issue about the nature of the asymmetry parameter, but also provides deeper physical insights into the origin of Fano resonance. Since the only assumption in our treatment is that the transport can be described by the Green’s function formalism, our results are also valid for broad disciplines including scattering problems of electromagnetic waves, acoustics, and seismology.

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2015-01-01

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Universal Flux-Fluctuation Law in Small Systems

Description

The relation between flux and fluctuation is fundamental to complex physical systems that support and transport flows. A recently obtained law predicts monotonous enhancement of fluctuation as the average flux is increased, which in principle is valid but only for

The relation between flux and fluctuation is fundamental to complex physical systems that support and transport flows. A recently obtained law predicts monotonous enhancement of fluctuation as the average flux is increased, which in principle is valid but only for large systems. For realistic complex systems of small sizes, this law breaks down when both the average flux and fluctuation become large. Here we demonstrate the failure of this law in small systems using real data and model complex networked systems, derive analytically a modified flux-fluctuation law, and validate it through computations of a large number of complex networked systems. Our law is more general in that its predictions agree with numerics and it reduces naturally to the previous law in the limit of large system size, leading to new insights into the flow dynamics in small-size complex systems with significant implications for the statistical and scaling behaviors of small systems, a topic of great recent interest.

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2014-10-27

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Water Footprint of Cities: A Review and Suggestions for Future Research

Description

Cities are hotspots of commodity consumption, with implications for both local and systemic water resources. Water flows “virtually” into and out of cities through the extensive cross-boundary exchange of goods and services. Both virtual and real water flows are affected

Cities are hotspots of commodity consumption, with implications for both local and systemic water resources. Water flows “virtually” into and out of cities through the extensive cross-boundary exchange of goods and services. Both virtual and real water flows are affected by water supply investments and urban planning decisions, which influence residential, commercial, and industrial development. This form of water “teleconnection” is being increasingly recognized as an important aspect of water decision-making. The role of trade and virtual water flows as an alternative to expanding a city’s “real” water supply is rarely acknowledged, with an emphasis placed instead on monotonic expansion of engineering potable water supplies. We perform a literature review of water footprint studies to evaluate the potential and importance of taking virtual flows into account in urban planning and policy. We compare and contrast current methods to assess virtual water flows. We also identify and discuss priorities for future research in urban water footprint analysis.

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2015-06-30

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Ventricular Shape and Relative Position Abnormalities in Preterm Neonates

Description

Recent neuroimaging findings have highlighted the impact of premature birth on subcortical development and morphological changes in the deep grey nuclei and ventricular system. To help characterize subcortical microstructural changes in preterm neonates, we recently implemented a multivariate tensor-based method

Recent neuroimaging findings have highlighted the impact of premature birth on subcortical development and morphological changes in the deep grey nuclei and ventricular system. To help characterize subcortical microstructural changes in preterm neonates, we recently implemented a multivariate tensor-based method (mTBM). This method allows to precisely measure local surface deformation of brain structures in infants. Here, we investigated ventricular abnormalities and their spatial relationships with surrounding subcortical structures in preterm neonates. We performed regional group comparisons on the surface morphometry and relative position of the lateral ventricles between 19 full-term and 17 preterm born neonates at term-equivalent age. Furthermore, a relative pose analysis was used to detect individual differences in translation, rotation, and scale of a given brain structure with respect to an average. Our mTBM results revealed broad areas of alterations on the frontal horn and body of the left ventricle, and narrower areas of differences on the temporal horn of the right ventricle. A significant shift in the rotation of the left ventricle was also found in preterm neonates. Furthermore, we located significant correlations between morphology and pose parameters of the lateral ventricles and that of the putamen and thalamus. These results show that regional abnormalities on the surface and pose of the ventricles are also associated with alterations on the putamen and thalamus. The complementarity of the information provided by the surface and pose analysis may help to identify abnormal white and grey matter growth, hinting toward a pattern of neural and cellular dysmaturation.

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Date Created
2017-05-28

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100-Year Love Story: The National Football League and Its Fandom

Description

The sport of football has become one of the most widely loved and watched sports in the United States. Fans of football are extremely dedicated to the sport and form very personal, emotional attachments to teams within the National Football

The sport of football has become one of the most widely loved and watched sports in the United States. Fans of football are extremely dedicated to the sport and form very personal, emotional attachments to teams within the National Football League. Through studying these fans, three main analysis topics will be addressed in this thesis: the established fan knowledge that creates rules within the fandom on how a fan participates and the exceptions to those rules, the need that fan's who do not fit into the normative patterns of the fandom feel to explain their motivations, and the degree of fanship that can be measured through a fan's explanation for their deviant behavior. For this fandom analysis, two sets of data will be referenced throughout the discussion. The first is anecdotal data pulled from various reddit threads on the personal experiences of each fan as well as some opinion sharing about the National Football League fandom. The second set of data is primary data that I have compiled via a survey. The established fan knowledge within this fandom is two fold: First, fans choose their team for a specific reason (usually based off of the team their parent's are a fan of or the state they grew up in), which typically takes place by age twelve. Secondly, once a fan chooses a team, they should stick with that team through their entire fanship. This second piece of fan knowledge is the most important rule within the fandom. This idea of loyalty is what guides fan participation. Identifying this rule led me to my main question about this fandom \u2014 if fans are so dedicated to their chosen team, what does it mean when someone switches to a new team. I feel that this breaking of a bond that seems so personal to fans is important and should be researched. This brought me to researching these fans that have switched teams, learning why, as well as what this group of fans can say about the National Football League fandom as a whole.

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Date Created
2017-05

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Inhibition of PKR phosphorylation by Vaccinia Virus' E3 Protein

Description

Vaccinia virus is a cytoplasmic, double-stranded DNA orthopoxvirus. Unlike mammalian cells, vaccinia virus produces double-stranded RNA (dsRNA) during its viral life cycle. The protein kinase R, PKR, is one of the principal host defense mechanisms against orthopoxvirus infection. PKR can

Vaccinia virus is a cytoplasmic, double-stranded DNA orthopoxvirus. Unlike mammalian cells, vaccinia virus produces double-stranded RNA (dsRNA) during its viral life cycle. The protein kinase R, PKR, is one of the principal host defense mechanisms against orthopoxvirus infection. PKR can bind double-stranded RNA and phosphorylate eukaryotic translation initiation factor, eIF2α, shutting down protein synthesis and halting the viral life cycle. To combat host defenses, vaccinia virus encodes E3, a potent inhibitor of the cellular anti-viral eIF2α kinase, PKR. The E3 protein contains a C-terminal dsRNA-binding motif that sequesters dsRNA and inhibits PKR activation. We demonstrate that E3 also interacts with PKR by co-immunoprecipitation. This interaction is independent of the presence of dsRNA and dsRNA-binding by E3, indicating that the interaction is not due to dsRNA-bridging.
PKR interaction mapped to a region within the dsRNA-binding domain of E3 and overlapped with sequences in the C-terminus of this domain that are necessary for binding to dsRNA. Point mutants of E3 were generated and screened for PKR inhibition and direct interaction. Analysis of these mutants demonstrates that dsRNA-binding but not PKR interaction plays a critical role in the broad host range of VACV. Nonetheless, full inhibition of PKR in cells in culture requires both dsRNA-binding and PKR interaction. Because E3 is highly conserved among orthopoxviruses, understanding the mechanisms that E3 uses to inhibit PKR can give insight into host range pathogenesis of dsRNA producing viruses.

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Date Created
2017-05

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The Adaptive Lasso Procedure for Building a Traffic Forecasting Model

Description

This paper will begin by initially discussing the potential uses and challenges of efficient and accurate traffic forecasting. The data we used includes traffic volume from seven locations on a busy Athens street in April and May of 2000. This

This paper will begin by initially discussing the potential uses and challenges of efficient and accurate traffic forecasting. The data we used includes traffic volume from seven locations on a busy Athens street in April and May of 2000. This data was used as part of a traffic forecasting competition. Our initial observation, was that due to the volatility and oscillating nature of daily traffic volume, simple linear regression models will not perform well in predicting the time-series data. For this we present the Harmonic Time Series model. Such model (assuming all predictors are significant) will include a sinusoidal term for each time index within a period of data. Our assumption is that traffic volumes have a period of one week (which is evidenced by the graphs reproduced in our paper). This leads to a model that has 6,720 sine and cosine terms. This is clearly too many coefficients, so in an effort to avoid over-fitting and having an efficient model, we apply the sub-setting algorithm known as Adaptive Lass.

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Date Created
2017-05

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The Legality of Fantasy Sports in the State of Arizona

Description

This research is solely based on the legality of fantasy sports in Arizona. At this time, these contests are deemed as illegal gambling and historically banned. Throughout my research I consider the many entities involved, particularly the Native American tribes.

This research is solely based on the legality of fantasy sports in Arizona. At this time, these contests are deemed as illegal gambling and historically banned. Throughout my research I consider the many entities involved, particularly the Native American tribes. I also go on to discuss a historical timeline of all the social, intellectual, and legal aspects within the industry and how it became so prevalent today.

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Date Created
2017-05

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A Business Perspective and Solutions to the Kidney Transplant Shortage

Description

This research was aimed at identifying the problems of the kidney transplant market and then proposing business-minded solutions. The methodology that was used to compile research was an industry analysis, a business model canvas, the lean startup methodology, academic papers,

This research was aimed at identifying the problems of the kidney transplant market and then proposing business-minded solutions. The methodology that was used to compile research was an industry analysis, a business model canvas, the lean startup methodology, academic papers, popular culture references, previous and present marketing campaigns, an internship at a local hospital, and organ transplant databases. The problems I identified was that kidney transplant industry was favorable but had few competitors, a mounting demand with a lack of supply, a lack of public awareness, negative public perception, and incorrectly focused marketing campaigns. The solutions that I constructed were the endorsement of grocery retail clinics as a step to prevent a future increase in demand for kidneys, a hybridized opt-in system that would increase the supply of transplantable kidneys, a public awareness campaign that would increase the public's awareness and shift it into a positive light, and a refocused marketing campaign that centered on why people become donors. The implementation of these solutions should be solution1, then solution 3 and 4, and then after the public has enough time to ruminate, employ solution 2.

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Date Created
2017-05