Tobias Jacobs
Abstract
The concept of hotlink assignment aims at reducing the navigation effort for the users of a Web directory or similar structure by inserting a limited number of additional hyperlinks called hotlinks. The k-hotlink assignment problem denotes the task of adding at most k outgoing hotlinks to each page of a tree-like site, minimizing the path length, that is, the expected number of “clicks” necessary for the user to reach her destination page. Another common formulation of this problem is to maximize the gain, that is, the path length reduction achieved by the assignment.
In this work we analyze the natural greedy strategy, proving that it reaches the optimal gain up to the constant factor of 2. Considering the gain, we also prove the existence of a PTAS. Finally, we give a polynomial-time 2-approximation for the 1-hotlink assignment problem, which constitutes the first constant factor approximation in terms of the path length. The algorithms' performance analyses are made possible by a set of three new basic operations for the transformation of hotlink assignments.
- Bose, P., Kranakis, E., Krizanc, D., Martin, M. V., Czyzowicz, J., Pelc, A., and Gasieniec, L. 2000. Strategies for hotlink assignments. In Proceedings of the 11th International Symposium on Algorithms and Computation (ISAAC). 23--34. Google Scholar
Digital Library
- Czyzowicz, J., Kranakis, E., Krizanc, D., Pelc, A., and Martin, M. V. 2001. Evaluation of hotlink assignment heuristics for improving web access. In Proceedings of the 2nd International Conference on Internet Computing (ICOMP). 793--799.Google Scholar
- Czyzowicz, J., Kranakis, E., Krizanc, D., Pelc, A., and Martin, M. V. 2003. Enhancing hyperlink structure for improving web performance. J. Web Engin. 1, 2, 93--127. Google ScholarDigital Library
- Czyzowicz, J., Kranakis, E., Krizanc, D., Pelc, A., and Vargas Martin, M. 2007. Optimal assignment of bookmarks to Web pages. Ars Combinatoria, LXXXII, 165--179.Google Scholar
- Douïeb, K. and Langerman, S. 2005. Dynamic hotlinks. In Proceedings of the 9th Workshop on Algorithms and Data Structures (WADS). 182--194. Google ScholarDigital Library
- Douïeb, K. and Langerman, S. 2006. Near-Entropy hotlink assignments. In Proceedings of the 14th Annual European Symposium on Algorithms (ESA). 292--303. Google ScholarDigital Library
- Fuhrmann, S., Krumke, S. O., and Wirth, H.-C. 2001. Multiple hotlink assignment. In Proceedings of the 27th International Workshop on Graph-Theoretic Concepts in Computer Science (WG). 189--200. Google ScholarDigital Library
- Gerstel, O., Kutten, S., Laber, E. S., Matichin, R., Peleg, D., Pessoa, A. A., and Souza, C. 2007. Reducing human interactions in web directory searches. ACM Trans. Inf. Syst. 25, 4, 20. Google ScholarDigital Library
- Jacobs, T. 2008a. An experimental study of recent hotlink assignment algorithms. In Proceedings of the 9th Workshop on Algorithm Engineering and Experiments and the 1st Workshop on Analytic Algorithmics and Combinatorics(ALENEX/ANALCO). 142--151.Google ScholarCross Ref
- Jacobs, T. 2008b. On the complexity of optimal hotlink assignment. In Proceedings of the 15th European Symphosium on Algorithms (ESA). 540--552. Google ScholarDigital Library
- Kranakis, E., Krizanc, D., and Martin, M. V. 2002. The hotlink optimizer. In Proceedings of the 3rd International Conference on Internet Computing (ICOMP). 87--94.Google Scholar
- Kranakis, E., Krizanc, D., and Shende, S. 2004. Approximate hotlink assignment. Inf. Process. Lett. 90, 3, 121--128. Google ScholarDigital Library
- Krishnan, P., Raz, D., and Shavitt, Y. 2000. The cache location problem. IEEE/ACM Trans. Netw. 8, 5, 568--582. Google ScholarDigital Library
- Krizanc, D., Langerman, S., and Morin, P. 2002. Asymmetric communication protocols via hotlink assignments. In Theory of Computing Systems, 33--40.Google Scholar
- Laber, E. S. and Molinaro, M. 2007. Improved approximations for the hotlink assignment problem and for binary searching on trees. Tech. rep., Departamento de Informática, Pontificia Universidade Católica do Rio de Janeiro.Google Scholar
- Li, K. and Shen, H. 2004. Optimal placement of web proxies for tree networks. In Proceedings of the IEEE International Conference on e-Technology, e-Commerce and e-Service (EEE). 479--486. Google ScholarDigital Library
- Matichin, R. and Peleg, D. 2003. Approximation algorithm for hotlink assignments in web directories. In Proceedings of the 8th Workshop on Algorithms and Data Structures (WADS). 271--280.Google Scholar
- Matichin, R. and Peleg, D. 2007. Approximation algorithm for hotlink assignment in the greedy model. Theor. Comput. Sci. 383, 1, 102--110. Google ScholarDigital Library
- Perkowitz, M. and Etzioni, O. 2000. Towards adaptive web sites: Conceptual framework and case study. Artif. Intell. 118, 1-2, 245--275. Google ScholarDigital Library
- Pessoa, A. A., Laber, E. S., and de Souza, C. 2004. Efficient algorithms for the hotlink assignment problem: The worst case search. In Proceedings of the 15th International Symposium on Algorithms and Computation (ISAAC). 778--792. Google ScholarDigital Library
Index Terms
- Constant factor approximations for the hotlink assignment problem
Recommendations
Improved approximations for the hotlink assignment problem
Let G=(V,E) be a graph representing a Web site, where nodes correspond to pages and arcs to hyperlinks. In this context, hotlinks are defined as shortcuts (new arcs) added to Web pages of G in order to reduce the time spent by users to reach their ...
Constant factor approximations for the hotlink assignment problem
WADS'07: Proceedings of the 10th international conference on Algorithms and Data StructuresAn approach for reducing the navigation effort for the users of a web site is to enhance its hyperlink structure with additional hotlinks. We address the task of adding at most one such additional outgoing edge to each page of a tree-like site, ...
A Constant Factor Approximation Algorithm for the Storage Allocation Problem
We study the storage allocation problem (SAP) which is a variant of the unsplittable flow problem on paths (UFPP). A SAP instance consists of a path $$P = (V,E)$$P=(V,E) and a set J of tasks. Each edge $$e \in E$$e E has a capacity $$c_e$$ce and each ...
Comments