scholarly journals Model selection in stock correlation networks

2021 ◽  
Author(s):  
Narges Alipourjeddi

In this research we construct market networks to study correlation between the price return for all Dow Jones, NASDAQ-100 and S&P 100 indices that were traded over a period of time. We consider market networks, which have stocks as nodes and edges corresponding to correlated stocks. Specifically, a winner-take-all approach is used to determine if two nodes are adjacent. We identify that all networks based on the connecting stocks of highly correlated price returns display a scale-free degree distribution. Additionally, we use features for representing different aspects of the network. The feature includes small connected sub-graphs with three and four vertices. We use an algorithm to count frequently the number of the graphlets for our mathematical models and our constructed networks. Each network is assigned an 8-dimensional vector. We present a model selection algorithm based on supervised learning. Our algorithm classifies our market networks with the best fitting mathematical model.

2021 ◽  
Author(s):  
Narges Alipourjeddi

In this research we construct market networks to study correlation between the price return for all Dow Jones, NASDAQ-100 and S&P 100 indices that were traded over a period of time. We consider market networks, which have stocks as nodes and edges corresponding to correlated stocks. Specifically, a winner-take-all approach is used to determine if two nodes are adjacent. We identify that all networks based on the connecting stocks of highly correlated price returns display a scale-free degree distribution. Additionally, we use features for representing different aspects of the network. The feature includes small connected sub-graphs with three and four vertices. We use an algorithm to count frequently the number of the graphlets for our mathematical models and our constructed networks. Each network is assigned an 8-dimensional vector. We present a model selection algorithm based on supervised learning. Our algorithm classifies our market networks with the best fitting mathematical model.


Author(s):  
Jeffrey M. Berry

The relationships between interest groups, political parties, and elections have always been dynamic, but in recent years change has accelerated in ways that have favored some interests over others. This chapter considers these developments as the result of a variety of factors, the most critical of which are the growth of polarization, a new legal landscape for campaign finance, and new organizational forms. The chapter goes on to suggest, that as bipartisanship has ebbed, elections have become winner-take-all affairs and interest groups are pushed to choose sides. The chapter further suggests that the rise of super PACs is especially notable as wealthy individuals have become increasingly important, single sources of campaign money, supplanting in part traditional interest groups, especially conventional PACs. It concludes that even as sums spent by super PACs and other interest groups have skyrocketed, the impact of their direct spending on persuading voters remains uncertain.


PLoS ONE ◽  
2017 ◽  
Vol 12 (9) ◽  
pp. e0182455 ◽  
Author(s):  
Nicole White ◽  
Miles Benton ◽  
Daniel Kennedy ◽  
Andrew Fox ◽  
Lyn Griffiths ◽  
...  

2011 ◽  
Vol 9 (3) ◽  
pp. 659-662 ◽  
Author(s):  
Brian Waddell

Jacob S. Hacker and Paul Pierson's Winner-Take-All Politics: How Washington Made the Rich Richer—And Turned Its Back on the Middle Class is both a work of political science and a contribution to broad public discussion of distributive politics. Its topic could not be more relevant to a US polity wracked by bitter partisan disagreements about taxes, social spending, financial regulation, social insecurity, and inequality. The political power of “the rich” is a theme of widespread public attention. The headline on the cover of the January–February 2011 issue of The American Interest—“Inequality and Democracy: Are Plutocrats Drowning Our Republic?”—is indicative. Francis Fukuyama's lead essay, entitled “Left Out,” clarifies that by “plutocracy,” the journal means “not just rule by the rich, but rule by and for the rich. We mean, in other words, a state of affairs in which the rich influence government in such a way as to protect and expand their own wealth and influence, often at the expense of others.” Fukuyama makes clear that he believes that this state of affairs obtains in the United States today.Readers of Perspectives on Politics will know that the topic has garnered increasing attention from political scientists in general and in our journal in particular. In March 2009, we featured a symposium on Larry Bartels's Unequal Democracy: The Political Economy of the New Gilded Age. And in December 2009, our lead article, by Jeffrey A. Winters and Benjamin I. Page, starkly posed the question “Oligarchy in the United States?” and answered it with an equally stark “yes.” Winner-Take-All Politics thus engages a broader scholarly discussion within US political science, at the same time that it both draws upon and echoes many “classic themes” of US political science from the work of Charles Beard and E. E. Schattschneider to Ted Lowi and Charles Lindblom.In this symposium, we have brought together a group of important scholars and commentators who offer a range of perspectives on the book and on the broader themes it engages. While most of our discussants are specialists on “American politics,” we have also sought out scholars beyond this subfield. Our charge to the discussants is to evaluate the book's central claims and evidence, with a focus on three related questions: 1) How compelling is its analysis of the “how” and “why” of recent US public policy and its “turn” in favor of “the rich” and against “the middle class”? 2) How compelling is its critique of the subfield of “American politics” for its focus on the voter–politician linkage and on “politics as spectacle” at the expense of an analysis of “politics as organized combat”? 3) And do you agree with its argument that recent changes in US politics necessitate a different, more comparative, and more political economy–centered approach to the study of US politics?—Jeffrey C. Isaac, Editor


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