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DTSTAMP:20261023T163312Z
LAST-MODIFIED:20140328T181258Z
DTSTART:20140409T133000Z
DTEND:20140409T150000Z
UID:event1265@bu.edu
URL:http://physics.bu.edu/internal/events/show/1265
SUMMARY:Opinion Models on Complex Networks
DESCRIPTION:Featuring Qian Li\n\nPart of the PhD Final Oral Exams.\n\nDisse
	rtation Committee:  H.E. Stanley\, William Klein\, Robert Carey\, William S
	kocpol\, Plamen Ivanov\n\nABSTRACT\nWe focus on non-consensus opinion model
	s in which above a certain threshold two opinions\ncoexist in a stable rela
	tionship. We revisit and extend the non-consensus opinion (NCO)\nmodel intr
	oduced by Shao et al. The NCO model in random networks displays a second\no
	rder phase transition that belongs to regular mean field percolation and is
	 characterized\nby the appearance (above a certain threshold) of a large sp
	anning cluster of the minority\nopinion. We generalize the NCO model by add
	ing a weight factor W to each individual’s\noriginal opinion when determi
	ning their future opinion (NCOW model). We find that as\nW increases the mi
	nority opinion holders tend to form stable clusters with a smaller initial\
	nminority fraction than in the NCO model. We also study another non-consens
	us opinion\nmodel based on the NCO model\, the inflexible contrarian opinio
	n (ICO) model\, which\nintroduces inflexible contrarians to model the compe
	tition between two opinions in a steady\nstate. Inflexible contrarians are 
	individuals that never change their original opinion but may\ninfluence the
	 opinions of others. The inflexible contrarians effectively decrease the si
	ze of the\nlargest rival-opinion cluster. All of the above models have prev
	iously been explored in terms\nof a single network\, but human communities 
	are usually interconnected\, not isolated. We\nstudy here the opinion dynam
	ics in coupled networks. We find that the interdependent links\neffectively
	 force the system from a second order phase transition\, which is character
	istic of\nthe NCO model on a single network\, to a hybrid phase transition\
	, i.e.\, a mix of second-order\nand abrupt jump-like transitions that ultim
	ately becomes\, as we increase the percentage of\nv\ninterdependent agents\
	, a pure abrupt transition. We conclude that for the NCO model on\ncoupled 
	networks\, interactions through interdependent links could push the non-con
	sensus\nopinion model to a consensus opinion model\, which mimics the reali
	ty that increased mass\ncommunication causes people to hold opinions that a
	re increasingly similar.\nMoreover we also study the NCO model on directed 
	networks. We define directionality\nas the percentage of unidirectional lin
	ks in a network\, and we use the linear correlation\ncoefficient between th
	e indegree and outdegree of a node to quantify the asymmetry between\nthe i
	ndegree and outdegree. We introduce two degree-preserving rewiring approach
	es which\nallow us to construct directed networks that can have a broad ran
	ge of possible combinations\nof directionality and linear correlation coeff
	icient to further study how directionality and\nlinear correlation coeffici
	ent impact opinion competitions. We find that as the directionality\nor the
	 indegree and outdegree correlation coefficient increase the majority opini
	on spread\nbetter becoming more dominant and it becomes harder for the mino
	rity opinion to survive.
LOCATION:PRB 595\, 3 Cummington Mall\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
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