scholarly journals Energy scaling and reduction in controlling complex networks

2016 ◽  
Vol 3 (4) ◽  
pp. 160064 ◽  
Author(s):  
Yu-Zhong Chen ◽  
Le-Zhi Wang ◽  
Wen-Xu Wang ◽  
Ying-Cheng Lai
Keyword(s):  
Energy Distribution ◽  
Real World ◽  
High Probability ◽  
Physical Theory ◽  
Scaling Law ◽  
Structural Elements ◽  
Nonlinear Dynamical ◽  
Energy Scaling ◽  
Structural Controllability ◽  
Shed Light

Recent works revealed that the energy required to control a complex network depends on the number of driving signals and the energy distribution follows an algebraic scaling law. If one implements control using a small number of drivers, e.g. as determined by the structural controllability theory, there is a high probability that the energy will diverge. We develop a physical theory to explain the scaling behaviour through identification of the fundamental structural elements, the longest control chains (LCCs), that dominate the control energy. Based on the LCCs, we articulate a strategy to drastically reduce the control energy (e.g. in a large number of real-world networks). Owing to their structural nature, the LCCs may shed light on energy issues associated with control of nonlinear dynamical networks.

scholarly journals Where the action could be: Speakers look at graspable objects and meaningful scene regions when describing potential actions

2019 ◽  
Author(s):  
Gwendolyn L Rehrig ◽  
Candace Elise Peacock ◽  
Taylor Hayes ◽  
Fernanda Ferreira ◽  
John M. Henderson
Keyword(s):  
Visual Attention ◽  
Real World ◽  
Language Production ◽  
Native English Speakers ◽  
English Speakers ◽  
Linguistic Processing ◽  
General Meaning ◽  
New Evidence ◽  
Shed Light ◽  
Better Than

The world is visually complex, yet we can efficiently describe it by extracting the information that is most relevant to convey. How do the properties of real-world scenes help us decide where to look and what to say? Image salience has been the dominant explanation for what drives visual attention and production as we describe displays, but new evidence shows scene meaning predicts attention better than image salience. Here we investigated the relevance of one aspect of meaning, graspability (the grasping interactions objects in the scene afford), given that affordances have been implicated in both visual and linguistic processing. We quantified image salience, meaning, and graspability for real-world scenes. In three eyetracking experiments, native English speakers described possible actions that could be carried out in a scene. We hypothesized that graspability would preferentially guide attention due to its task-relevance. In two experiments using stimuli from a previous study, meaning explained visual attention better than graspability or salience did, and graspability explained attention better than salience. In a third experiment we quantified image salience, meaning, graspability, and reach-weighted graspability for scenes that depicted reachable spaces containing graspable objects. Graspability and meaning explained attention equally well in the third experiment, and both explained attention better than salience. We conclude that speakers use object graspability to allocate attention to plan descriptions when scenes depict graspable objects within reach, and otherwise rely more on general meaning. The results shed light on what aspects of meaning guide attention during scene viewing in language production tasks.

scholarly journals Molecular requirements for the formation of a kinetochore–microtubule interface by Dam1 and Ndc80 complexes

2012 ◽  
Vol 200 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Fabienne Lampert ◽  
Christine Mieck ◽  
Gregory M. Alushin ◽  
Eva Nogales ◽  
Stefan Westermann
Keyword(s):  
Chromosome Segregation ◽  
Protein Complexes ◽  
Structural Elements ◽  
Large Protein ◽  
Kinetochore Assembly ◽  
Sister Chromatids ◽  
Dam1 Complex ◽  
Shed Light ◽  
Kinetochore Function

Kinetochores are large protein complexes that link sister chromatids to the spindle and transduce microtubule dynamics into chromosome movement. In budding yeast, the kinetochore–microtubule interface is formed by the plus end–associated Dam1 complex and the kinetochore-resident Ndc80 complex, but how they work in combination and whether a physical association between them is critical for chromosome segregation is poorly understood. Here, we define structural elements required for the Ndc80–Dam1 interaction and probe their function in vivo. A novel ndc80 allele, selectively impaired in Dam1 binding, displayed growth and chromosome segregation defects. Its combination with an N-terminal truncation resulted in lethality, demonstrating essential but partially redundant roles for the Ndc80 N-tail and Ndc80–Dam1 interface. In contrast, mutations in the calponin homology domain of Ndc80 abrogated kinetochore function and were not compensated by the presence of Dam1. Our experiments shed light on how microtubule couplers cooperate and impose important constraints on structural models for outer kinetochore assembly.

scholarly journals A Theory of Experimenters: Robustness, Randomization, and Balance

2020 ◽  
Vol 110 (4) ◽  
pp. 1206-1230 ◽  
Author(s):  
Abhijit V. Banerjee ◽  
Sylvain Chassang ◽  
Sergio Montero ◽  
Erik Snowberg
Keyword(s):  
Decision Maker ◽  
Real World ◽  
Robust Performance ◽  
Control Groups ◽  
Trade Off ◽  
Performance Guarantees ◽  
Important Concern ◽  
Expected Performance ◽  
And Control ◽  
Shed Light

This paper studies the problem of experiment design by an ambiguity-averse decision-maker who trades off subjective expected performance against robust performance guarantees. This framework accounts for real-world experimenters’ preference for randomization. It also clarifies the circumstances in which randomization is optimal: when the available sample size is large and robustness is an important concern. We apply our model to shed light on the practice of rerandomization, used to improve balance across treatment and control groups. We show that rerandomization creates a trade-off between subjective performance and robust performance guarantees. However, robust performance guarantees diminish very slowly with the number of rerandomizations. This suggests that moderate levels of rerandomization usefully expand the set of acceptable compromises between subjective performance and robustness. Targeting a fixed quantile of balance is safer than targeting an absolute balance objective. (JEL C90, D81)

A new edge-based energy scaling law for W7-AS and its implications for boundary-island divertor operation

2007 ◽  
Vol 363-365 ◽  
pp. 389-394 ◽  
Author(s):  
K. McCormick ◽  
P. Grigull ◽  
H. Ehmler ◽  
E. Pasch
Keyword(s):  
Scaling Law ◽  
Energy Scaling ◽  
Edge Based

From Evidence-Based Practice in Suicide Prevention to the Real World: How Long is the Leap?

2009 ◽  
Vol 24 (S1) ◽  
pp. 1-1
Author(s):  
M. Pompili
Keyword(s):  
Suicide Prevention ◽  
Mental Health Professionals ◽  
Real World ◽  
Evidence Based Practice ◽  
Primary Care Providers ◽  
Evidence Based ◽  
Care Providers ◽  
The Real ◽  
The Everyday ◽  
Shed Light

This presentation aims to shed light on effective suicide prevention activities that often are missing in the everyday clinical practice. Too often in fact suicidal individuals seek help from mental health professionals that nevertheless fail to recognize suicide risk. For instance, on average, 45% of suicide victims had contact with primary care providers within 1 month of suicide. Likewise, the real world often presents challenges that impair proper utilization of the evidence-based practice. Also, the alarming suicide rates around the world points to lack of effective preventive understanding of suicide. This presentation will present key point of the evidence-based practice, how to implement such approach and how to overcome difficulties in the real world. It will deal with the state of the art of preventive measures of suicide, what the missing elements are and how to make the most from personal experience without risking relying on clinician's intuition in management of suicidal individuals.

scholarly journals In harm’s way, but not stressed about it: On the antecedents and consequences of belief in COVID-19 conspiracy theories

2021 ◽  
Author(s):  
Javier Granados Samayoa ◽  
Courtney Moore ◽  
Benjamin Ruisch ◽  
Shelby Taylor Boggs ◽  
Jesse T. Ladanyi ◽  
...  
Keyword(s):  
Real World ◽  
Economic Consequences ◽  
Conspiracy Theory ◽  
Scientific Advice ◽  
Conspiracy Theories ◽  
Social Distancing ◽  
General Stress ◽  
Antecedents And Consequences ◽  
Shed Light ◽  
Psychological Benefit

Conspiracy theories proliferate during times of turmoil. Not surprisingly, the COVID-19 pandemic has created an environment in which virus-related conspiracy theories have thrived. The current study leverages prior research to shed light on the antecedents and consequences of conspiracy theory beliefs in the important, real-world context of the COVID-19 pandemic. Specifically, we found that suffering greater negative economic consequences due to the pandemic predicted greater belief in COVID-19 conspiracy theories, and this relation was strongest among those generally inclined to believe conspiracy theories. We then examined the consequences of coming to hold such beliefs. Greater endorsement of COVID-19 conspiracy theories predicted less social distancing behavior, greater minimization of the threat of COVID-19, and lower levels of general stress. These findings replicate and extend prior research showing a link between conspiracy theory beliefs and rejection of scientific advice, but also offer evidence pointing to a psychological benefit of believing conspiracy theories.

scholarly journals Solving Vertex Cover in Polynomial Time on Hyperbolic Random Graphs

2021 ◽  
Author(s):  
Thomas Bläsius ◽  
Philipp Fischbeck ◽  
Tobias Friedrich ◽  
Maximilian Katzmann
Keyword(s):  
Computational Complexity ◽  
Structural Properties ◽  
Random Graphs ◽  
Polynomial Time ◽  
Real World ◽  
Degree Distribution ◽  
High Probability ◽  
Vertex Cover ◽  
Optimal Solution ◽  
Np Complete

AbstractThe computational complexity of the VertexCover problem has been studied extensively. Most notably, it is NP-complete to find an optimal solution and typically NP-hard to find an approximation with reasonable factors. In contrast, recent experiments suggest that on many real-world networks the run time to solve VertexCover is way smaller than even the best known FPT-approaches can explain. We link these observations to two properties that are observed in many real-world networks, namely a heterogeneous degree distribution and high clustering. To formalize these properties and explain the observed behavior, we analyze how a branch-and-reduce algorithm performs on hyperbolic random graphs, which have become increasingly popular for modeling real-world networks. In fact, we are able to show that the VertexCover problem on hyperbolic random graphs can be solved in polynomial time, with high probability. The proof relies on interesting structural properties of hyperbolic random graphs. Since these predictions of the model are interesting in their own right, we conducted experiments on real-world networks showing that these properties are also observed in practice.

scholarly journals Computing top-k temporal closeness in temporal networks

2022 ◽  
Author(s):  
Lutz Oettershagen ◽  
Petra Mutzel
Keyword(s):  
Real World ◽  
High Probability ◽  
Transitive Closure ◽  
Closeness Centrality ◽  
Data Sets ◽  
Temporal Networks ◽  
Real World Data ◽  
World Data ◽  
Temporal Domain ◽  
Vertex Sets

AbstractThe closeness centrality of a vertex in a classical static graph is the reciprocal of the sum of the distances to all other vertices. However, networks are often dynamic and change over time. Temporal distances take these dynamics into account. In this work, we consider the harmonic temporal closeness with respect to the shortest duration distance. We introduce an efficient algorithm for computing the exact top-k temporal closeness values and the corresponding vertices. The algorithm can be generalized to the task of computing all closeness values. Furthermore, we derive heuristic modifications that perform well on real-world data sets and drastically reduce the running times. For the case that edge traversal takes an equal amount of time for all edges, we lift two approximation algorithms to the temporal domain. The algorithms approximate the transitive closure of a temporal graph (which is an essential ingredient for the top-k algorithm) and the temporal closeness for all vertices, respectively, with high probability. We experimentally evaluate all our new approaches on real-world data sets and show that they lead to drastically reduced running times while keeping high quality in many cases. Moreover, we demonstrate that the top-k temporal and static closeness vertex sets differ quite largely in the considered temporal networks.

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