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Institution

Koç University

EducationIstanbul, Turkey
About: Koç University is a education organization based out in Istanbul, Turkey. It is known for research contribution in the topics: Population & Laser. The organization has 3655 authors who have published 10332 publications receiving 189827 citations.


Papers
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Journal ArticleDOI
TL;DR: This paper used a generalized vector autoregressive framework to characterize daily volatility spillovers across US stock, bond, foreign exchange and commodities markets, from January 1999 to January 2010, and showed that despite significant volatility fluctuations in all four markets during the sample, cross-market volatility spillover were quite limited until the global financial crisis, which began in 2007.

2,688 citations

Journal ArticleDOI
TL;DR: In this paper, the authors provide a detailed overview and historical perspective on state-of-the-art solutions, and elaborate on the fundamental differences with other technologies, the most important open research issues to tackle, and the reasons why the use of reconfigurable intelligent surfaces necessitates to rethink the communication-theoretic models currently employed in wireless networks.
Abstract: The future of mobile communications looks exciting with the potential new use cases and challenging requirements of future 6th generation (6G) and beyond wireless networks. Since the beginning of the modern era of wireless communications, the propagation medium has been perceived as a randomly behaving entity between the transmitter and the receiver, which degrades the quality of the received signal due to the uncontrollable interactions of the transmitted radio waves with the surrounding objects. The recent advent of reconfigurable intelligent surfaces in wireless communications enables, on the other hand, network operators to control the scattering, reflection, and refraction characteristics of the radio waves, by overcoming the negative effects of natural wireless propagation. Recent results have revealed that reconfigurable intelligent surfaces can effectively control the wavefront, e.g., the phase, amplitude, frequency, and even polarization, of the impinging signals without the need of complex decoding, encoding, and radio frequency processing operations. Motivated by the potential of this emerging technology, the present article is aimed to provide the readers with a detailed overview and historical perspective on state-of-the-art solutions, and to elaborate on the fundamental differences with other technologies, the most important open research issues to tackle, and the reasons why the use of reconfigurable intelligent surfaces necessitates to rethink the communication-theoretic models currently employed in wireless networks. This article also explores theoretical performance limits of reconfigurable intelligent surface-assisted communication systems using mathematical techniques and elaborates on the potential use cases of intelligent surfaces in 6G and beyond wireless networks.

2,021 citations

Journal ArticleDOI
TL;DR: In this paper, the authors propose several connectedness measures built from pieces of variance decomposition positions, and argue that they provide natural and insightful measures of connectedness among nancial asset returns and volatilities.

1,912 citations

Journal ArticleDOI
27 May 2011-Science
TL;DR: The differences across cultures in the enforcement of conformity may reflect their specific histories and advances knowledge that can foster cross-cultural understanding in a world of increasing global interdependence and has implications for modeling cultural change.
Abstract: With data from 33 nations, we illustrate the differences between cultures that are tight (have many strong norms and a low tolerance of deviant behavior) versus loose (have weak social norms and a high tolerance of deviant behavior). Tightness-looseness is part of a complex, loosely integrated multilevel system that comprises distal ecological and historical threats (e.g., high population density, resource scarcity, a history of territorial conflict, and disease and environmental threats), broad versus narrow socialization in societal institutions (e.g., autocracy, media regulations), the strength of everyday recurring situations, and micro-level psychological affordances (e.g., prevention self-guides, high regulatory strength, need for structure). This research advances knowledge that can foster cross-cultural understanding in a world of increasing global interdependence and has implications for modeling cultural change.

1,895 citations

Journal ArticleDOI
TL;DR: In this article, the authors provide a simple and intuitive measure of interdependence of asset returns and/or volatilities, and formulate and examine precise and separate measures of return spillovers and volatility spillovers.
Abstract: We provide a simple and intuitive measure of interdependence of asset returns and/or volatilities. In particular, we formulate and examine precise and separate measures of return spillovers and volatility spillovers. Our framework facilitates study of both non-crisis and crisis episodes, including trends and bursts in spillovers, and both turn out to be empirically important. In particular, in an analysis of sixteen global equity markets from the early 1990s to the present, we find striking evidence of divergent behavior in the dynamics of return spillovers vs. volatility spillovers: Return spillovers display a gently increasing trend but no bursts, whereas volatility spillovers display no trend but clear bursts.

1,743 citations


Authors

Showing all 3781 results

NameH-indexPapersCitations
Ruth Nussinov11472752320
Thomas W. Smith9873537246
Metin Sitti8754128294
Andrew J. Coates8061123275
Alfred Mahr7322922581
Umran S. Inan6944518403
Hülya Kayserili6125615397
Buyong Ma6121716506
Christian Holm6038114067
Turan G. Bali5919310531
John Shalf5523613215
Mehmet Kanbay543709894
N. Volkan Adsay5214611971
Ozlem Keskin511809823
Gün R. Semin502048819
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20241
202349
2022194
20211,440
20201,266
2019990