6,925 research outputs found
A fine grained heuristic to capture web navigation patterns
In previous work we have proposed a statistical model to capture the user behaviour when browsing the web. The user navigation information obtained from web logs is modelled as a hypertext probabilistic grammar (HPG) which
is within the class of regular probabilistic grammars. The set of highest probability strings generated by the grammar corresponds to the user preferred navigation trails. We have previously conducted experiments with a Breadth-First Search algorithm (BFS) to perform the exhaustive computation of all the strings with probability above a specified cut-point, which we call the rules. Although the algorithm’s running time varies linearly with the number of grammar states, it has the drawbacks of returning a large number of rules when the cut-point is small and a small set of very short rules when the cut-point is high.
In this work, we present a new heuristic that implements an iterative deepening search wherein the set of rules is incrementally augmented by first exploring trails with high probability. A stopping parameter is provided which measures the distance between the current rule-set and its corresponding maximal set obtained by the BFS algorithm. When the stopping parameter takes the value zero the heuristic corresponds to the BFS algorithm and as the parameter takes
values closer to one the number of rules obtained decreases accordingly.
Experiments were conducted with both real and synthetic data and the results show that for a given cut-point the number of rules induced increases smoothly with the decrease of the stopping criterion. Therefore, by setting the value of the stopping criterion the analyst can determine the number and quality of rules to be induced; the quality of a rule is measured by both its length and probability
A Framework for Exploring and Evaluating Mechanics in Human Computation Games
Human computation games (HCGs) are a crowdsourcing approach to solving
computationally-intractable tasks using games. In this paper, we describe the
need for generalizable HCG design knowledge that accommodates the needs of both
players and tasks. We propose a formal representation of the mechanics in HCGs,
providing a structural breakdown to visualize, compare, and explore the space
of HCG mechanics. We present a methodology based on small-scale design
experiments using fixed tasks while varying game elements to observe effects on
both the player experience and the human computation task completion. Finally
we discuss applications of our framework using comparisons of prior HCGs and
recent design experiments. Ultimately, we wish to enable easier exploration and
development of HCGs, helping these games provide meaningful player experiences
while solving difficult problems.Comment: 11 pages, 5 figure
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