scholarly journals The hourglass effect in hierarchical dependency networks

2017 ◽  
Vol 5 (4) ◽  
pp. 490-528 ◽  
Author(s):  
KAESER M. SABRIN ◽  
CONSTANTINE DOVROLIS
Keyword(s):  
Low Complexity ◽  
Core Size ◽  
Original Network ◽  
Hierarchical Network ◽  
Modular Systems ◽  
The Core ◽  
Dependency Networks ◽  
Dependency Network ◽  
Hierarchical Dependency ◽  
Almost All

AbstractMany hierarchically modular systems are structured in a way that resembles an hourglass. This “hourglass effect” means that the system generates many outputs from many inputs through a relatively small number of intermediate modules that are critical for the operation of the entire system, referred to as the waist of the hourglass. We investigate the hourglass effect in general, not necessarily layered, hierarchical dependency networks. Our analysis focuses on the number of source-to-target dependency paths that traverse each vertex, and it identifies the core of a dependency network as the smallest set of vertices that collectively cover almost all dependency paths. We then examine if a given network exhibits the hourglass property or not, comparing its core size with a “flat” (i.e., non-hierarchical) network that preserves the source dependencies of each target in the original network. As a possible explanation for the hourglass effect, we propose the Reuse Preference model that captures the bias of new modules to reuse intermediate modules of similar complexity instead of connecting directly to sources or low complexity modules. We have applied the proposed framework in a diverse set of dependency networks from technological, natural, and information systems, showing that all these networks exhibit the general hourglass property but to a varying degree and with different waist characteristics.

Dependency network-based approach to the implicit structure and semantic diffusion modes of semantic prosody

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jianpeng Liu ◽  
Luyao Zhang ◽  
Xiaohui Bai
Keyword(s):  
Internal Structure ◽  
Shortest Path ◽  
Path Length ◽  
Cognitive Approach ◽  
Function Words ◽  
The Core ◽  
Dependency Networks ◽  
Dependency Network ◽  
Large Clusters ◽  
Semantic Prosody

Abstract This paper studies the implicit structures and the diffusion modes of semantic prosody on the dependency networks of some English words such as cause and their Chinese equivalents. It is found that the structure of semantic prosody is a bi-stratified network consisting of a few large clusters gathering in the center with most nodes of low dependency capability scattered around. With regard to the diffusion modes, results show that: (i) within one shortest path length, the core words directly attract the nodes with the same or similar semantic characteristics and exclude those with conflicting ones, creating the clearest and the most intense semantic diffusion; (ii) over one shortest path length, semantic diffusion is achieved through content words or function words, and the semantic diffusion modes created with function words as bridges are relatively vaguer and more complicated ones. This conclusion also results in the semantic prosodies of other English words and their Chinese equivalent words, revealing, to some extent, a common cognitive approach to understanding the internal structure and the diffusion modes of semantic prosody.

scholarly journals Geometrical Scaling of Antiresonant Hollow-Core Fibers for Mid-Infrared Beam Delivery

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 420
Author(s):  
Ang Deng ◽  
Wonkeun Chang
Keyword(s):  
Structural Parameters ◽  
Transmission Band ◽  
Confinement Loss ◽  
Hollow Core ◽  
Core Size ◽  
Core Diameter ◽  
Mid Infrared ◽  
The Core ◽  
Tubular Type ◽  
Beam Delivery

We numerically investigate the effect of scaling two key structural parameters in antiresonant hollow-core fibers—dielectric wall thickness of the cladding elements and core size—in view of low-loss mid-infrared beam delivery. We demonstrate that there exists an additional resonance-like loss peak in the long-wavelength limit of the first transmission band in antiresonant hollow-core fibers. We also find that the confinement loss in tubular-type hollow-core fibers depends strongly on the core size, where the degree of the dependence varies with the cladding tube size. The loss scales with the core diameter to the power of approximately −5.4 for commonly used tubular-type hollow-core fiber designs.

Revising the Assumption that Ḥadīṯ Studies Flourished in the 11th/17th-Century Ḥiǧāz: Ibrāhīm al-Kūrānī’s (d. 1101/1690) Contribution

Arabica ◽  
2021 ◽  
Vol 68 (1) ◽  
pp. 1-35
Author(s):  
Naser Dumairieh
Keyword(s):  
General Framework ◽  
18Th Century ◽  
Critical Role ◽  
17Th Century ◽  
Main Interest ◽  
Islamic World ◽  
The Core ◽  
Revival Movement ◽  
Almost All

Abstract The Ḥiǧāz in the 11th/17th century has long been considered the center of a “revival” movement in ḥadīṯ studies. This assumption has spread widely among scholars of the 11th-/17th- and 12th-/18th-century Islamic world based on the fact that the isnāds of many major ḥadīṯ scholars from almost all parts of the Islamic world from the 11th/17th century onward return to a group of scholars in the Ḥiǧāz. The scholarly group that is assumed to have played a critical role in the flourishing of ḥadīṯ studies in the 11th/17th-century Ḥiǧāz is called the al-Ḥaramayn circle or network. However, to date, there have been no studies that investigate what was actually happening in that century concerning ḥadīṯ studies. Examining the actual ḥadīṯ studies of one of the scholars at the core of al-Ḥaramayn circle, i.e. Ibrāhīm b. Ḥasan al-Kūrānī, will unpack the main interest of Ḥiǧāzī scholars in ḥadīṯ literature, reveal previously unstudied aspects of ḥadīṯ studies in the 11th/17th-century Ḥiǧāz, correct some unexamined assumptions, and situate the ḥadīṯ efforts of scholars of the 11th/17th-century Ḥiǧāz within a general framework of developments within ḥadīṯ studies.

scholarly journals All-fiber passively Q-switched ytterbium doped double-clad fiber lasers: experiment And modeling.

2021 ◽  
Author(s):  
Yi Lu
Keyword(s):  
Pulse Energy ◽  
Traveling Wave ◽  
Pulse Width ◽  
Fiber Lasers ◽  
Peak Power ◽  
Wave Model ◽  
Core Size ◽  
The Core ◽  
Q Switching ◽  
Output Characteristics

All-fiber passively Q-switched lasers were demonstrated using ytterbium-doped double cladding fiber (YDF) as an active medium. The laser was pumped by three 25W, 975nm fiber coupled diodes and Q-switching was initiated when the amplified spontaneous emission generated in the core of the gain fiber bleached the saturable absorber (SA). A piece of samarium-doped fiber was used as SA in first configuration and pulses with 68μJ pulse energy and 210ns pulse width were obtained. In second configuration, a piece of ytterbium-doped fiber with much smaller core size was used as SA to produce pulse energy of 86μJ. The last configuration incorporated a 9m-long YDF as gain fiber. The far end from pump was acting as SA in this case and pulses with 82μJ pulse energy and 148ns pulse width were observed. The peak power was estimated at 554W. Traveling wave model was implemented to numerically simulate the output characteristics versus pump power.

Polynomial Entropy of the Logistic Map

2021 ◽  
Vol 58 (2) ◽  
pp. 206-215
Author(s):  
Milan Perić
Keyword(s):  
Topological Entropy ◽  
Logistic Map ◽  
Low Complexity ◽  
Almost All

We study the polynomial entropy of the logistic map depending on a parameter, and we calculate it for almost all values of the parameter. We show that polynomial entropy distinguishes systems with a low complexity (i.e. for which the topological entropy vanishes).

Solution-Responsive Particle Size Adaptivity in Lagrangian Vortex Particle Methods

2021 ◽  
Author(s):  
Mark J. Stock ◽  
Adrin Gharakhani
Keyword(s):  
Particle Size ◽  
Particle Method ◽  
Adaptive Method ◽  
Particle Methods ◽  
Core Size ◽  
Large Particle Size ◽  
The Core ◽  
Vortex Particle Method ◽  
Computational Resources ◽  
Vortex Particle

Abstract In order to minimize the computational resources necessary for a given level of accuracy in a Lagrangian Vortex Particle Method, a novel particle core size adaptivity scheme has been created. The method adapts locally to the solution while preventing large particle size gradients, and optionally adapts globally to focus effort on important regions. It is implemented in the diffusion solver, which uses the Vorticity Redistribution Method, by allowing and accounting for variations in the core radius of participating particles. We demonstrate the effectiveness of this new method on the diffusion of a δ-function and impulsively started flow over a circular cylinder at Re = 9,500. In each case, the adaptive method provides solutions with marginal loss of accuracy but with substantially fewer computational elements.

"The Second New Near"

1993 ◽  
Vol 14 (1) ◽  
pp. 3-3
Keyword(s):  
The Self ◽  
Self Assessment ◽  
The Core ◽  
Core Content ◽  
Second Year ◽  
Almost All

With this volume, Pediatrics In Review begins its second year of publication with the new format and with most of the material being based on the core content statements developed by the American Board of Pediatrics that are the basis of the examination for renewal of certification. Of the more than 3800 such statements so far developed, we covered more than 1000 in 1992 and, more important, more than 300 of the 900 from which the 1993 examination will be based. By mid-1993, Pediatrics in Review plus the self assessment part of PREP will have covered almost all of these core content statements, thereby enabling those who are preparing for the examination to be well-prepared.

Conclusion

2020 ◽  
pp. 244-260
Author(s):  
Stefanie Walter ◽  
Ari Ray ◽  
Nils Redeker
Keyword(s):  
Policy Implications ◽  
European Council ◽  
Future Research ◽  
Policy Options ◽  
European Level ◽  
Eurozone Crisis ◽  
Policy Issues ◽  
The Core ◽  
Scant Attention ◽  
Almost All

The concluding chapter begins by summarizing and discussing the insights that this book has generated. It has addressed three aspects that have received scant attention in existing research: The importance of analyzing the Eurozone crisis in comparative perspective, the importance of examining the whole range of policy options, including the ones not chosen, and the importance of analyzing crisis politics not just in deficit-debtor, but also in surplus-creditor countries. Because the bulk of the book’s analyses have focused on domestic distributive struggles, the concluding chapter turns to the question to what extent the book’s approach is useful for understanding the distributive struggles on the European level as well. For this purpose, the chapter examines how surplus and deficit states positioned themselves with regard to the core EMU-related issues and reforms that were discussed in the European Council during the Eurozone crisis. The analysis shows that on policy issues related to questions of adjustment and financing, deficit and surplus countries aligned in opposing camps. Moreover, creditor-surplus countries managed to secure policy decisions in line with their preferences on almost all adjustment-related policy issues. This meant that deficit countries had to carry the bulk of the adjustment burden. In contrast, surplus countries showed more willingness to compromise on issues related to financing. The chapter concludes with a discussion of the policy implications of the findings and offers an agenda for future research.

Evolutionary developmental biology

2018 ◽  
Author(s):  
Ron Amundson
Keyword(s):  
Developmental Biology ◽  
Evolutionary Developmental Biology ◽  
Developmental Genetics ◽  
Comparative Biology ◽  
Embryological Development ◽  
Adult Form ◽  
The Core ◽  
Almost All ◽  
Evo Devo ◽  
Year 2000

Evolutionary developmental biology is the study of evolutionary change (called phylogeny) as it is revealed through the embryological development of individual organisms (called ontogeny). On this approach, the understanding of ontogeny contributes to our understanding of phylogeny, and vice versa. Evolutionary thinkers of the nineteenth century almost all held what may be called the core doctrine of evolutionary developmental biology: that in order to achieve a modification in the adult form, evolution must modify the embryological processes responsible for that form, so that an understanding of evolution requires an understanding of development. Evolutionary theory has no theoretical need for developmental views of evolution. Beginning around 1990 a series of discoveries and theoretical innovations in developmental genetics led to the reinvigoration of developmental approaches to evolution. Evolutionary developmental biology (‘evo-devo’ as it is now called) was inaugurated as a Division of the Society for Integrative and Comparative Biology in the year 2000.

Core@shell nanostructured Au-d@NimPtm for electrochemical oxygen reduction reaction: effect of the core size and shell thickness

2019 ◽  
Vol 9 (17) ◽  
pp. 4668-4677 ◽  
Author(s):  
Min Zhang ◽  
Shu Miao ◽  
Bo-Qing Xu
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Shell Thickness ◽  
Reduction Reaction ◽  
Core Shell ◽  
Core Size ◽  
The Core ◽  
Electrocatalytic Performance ◽  
Electrochemical Oxygen

Au-d@NimPtm nanostructures are studied to address the effects of the Au-core size (d) and NiPt-shell thickness (m) on the electrocatalytic performance of Pt for the ORR.

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