TY - GEN

T1 - On approximation of bookmark assignments

AU - Asahiro, Yuichi

AU - Miyano, Eiji

AU - Murata, Toshihide

AU - Ono, Hirotaka

PY - 2007

Y1 - 2007

N2 - Consider a rooted directed acyclic graph G = (V, E) with root r, representing a collection V of web pages connected via a set E of hyperlinks. Each node v is associated with the probability that a user wants to access the node v. The access cost is defined as the expected number of steps required to reach a node from the root r. A bookmark is an additional shortcut from r to a node of G, which may reduce the access cost. The bookmark assignment problem is to find a set of bookmarks that achieves the greatest improvement in the access cost. For the problem, the paper presents a polynomial time approximation algorithm with factor (1 -1/e), and shows that there exists no polynomial time approximation algorithm with a better constant factor than (1-1/e) unless NP ⊆ DTIME(NO(log log N)), where N is the size of the inputs.

AB - Consider a rooted directed acyclic graph G = (V, E) with root r, representing a collection V of web pages connected via a set E of hyperlinks. Each node v is associated with the probability that a user wants to access the node v. The access cost is defined as the expected number of steps required to reach a node from the root r. A bookmark is an additional shortcut from r to a node of G, which may reduce the access cost. The bookmark assignment problem is to find a set of bookmarks that achieves the greatest improvement in the access cost. For the problem, the paper presents a polynomial time approximation algorithm with factor (1 -1/e), and shows that there exists no polynomial time approximation algorithm with a better constant factor than (1-1/e) unless NP ⊆ DTIME(NO(log log N)), where N is the size of the inputs.

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U2 - 10.1007/978-3-540-74456-6_12

DO - 10.1007/978-3-540-74456-6_12

M3 - Conference contribution

AN - SCOPUS:38049040864

SN - 9783540744559

T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

SP - 115

EP - 124

BT - Mathematical Foundations of Computer Science 2007 - 32nd International Symposium, MFCS 2007, Proceedings

PB - Springer Verlag

T2 - 32nd International Symposium on Mathematical Foundations of Computer Science, MFCS 2007

Y2 - 26 August 2007 through 31 August 2007

ER -