An exploratory study is described in which the same text was presented to subjects in one of four formats, of which two were hypertext (TIES and Hypercard) and two were linear (Word Processor and paper). Subjects were required to use the text to answer 12 questions. Measurement was made of their time and accuracy and their movement through the document was recorded, in addition to a variety of ...

We consider the unit-demand min-buying pricing problem, in which we want to compute revenue maximizing prices for a set of products P assuming that each consumer from a set of consumer samples C will purchase her cheapest affordable product once prices are fixed. We focus on the special uniform-budget case, in which every consumer has only a single non-zero budget for some set of products. This...

Themaximum independent set problem (MAXIS) on general graphs is known to beNPhard to approximate within a factor of n1−ǫ, for any ǫ > 0. However, there are many “easy” classes of graphs on which the problem can be solved in polynomial time. In this context, an interesting question is that of computing the maximum independent set in a graph that can be expressed as the union of a small number of...

An independent set Ic is a critical independent set if |Ic|−|N(Ic)| ≥ |J | − |N(J)|, for any independent set J . The critical independence number of a graph is the cardinality of a maximum critical independent set. This number is a lower bound for the independence number and can be computed in polynomial-time. Any graph can be decomposed into two subgraphs where the independence number of one s...

We consider the problem of providing a resolution proof of the statement that a given graph with n vertices and A n edges does not contain an independent set of size k. For randomly chosen graphs with constant A, we show that such proofs almost surely require size exponential in n. Further; f o r A = o(n1f5) and any k 5 n/5, we show that these proofs almost surely require size 2”‘ for some glob...

We present a novel probabilistic rating system for team competitions. Building upon TrueSkill, we change the factor graph structure to cope with the problems of TrueSkill, e.g., multiway ties and variable team size. We give detailed inference algorithms for the new structure. Experimental results show a significant improvement over TrueSkill.

The Maximum Weight Independent Set (MWIS) problem on graphs with vertex weights asks for a set of pairwise nonadjacent vertices of maximum total weight. MWIS is known to be NP -complete in general, even under various restrictions. Let Si,j,k be the graph consisting of three induced paths of lengths i, j, k with a common initial vertex. The complexity of the MWIS problem for S1,2,2-free graphs, ...

A new technique for lighting participating media is suggested. The technique is based on the lattice-Boltzmann method, which is gaining popularity as alternative to finite-element methods for flow computations, due to its ease of implementation and ability to handle complex boundary conditions. A relatively simple, grid-based photon transport model is postulated and then shown to describe, in t...

We introduce a formal model of teaching in which the teacher is tailored to a particular learner, yet the teaching protocol is designed so that no collusion is possible. Not surprisingly, such a model remedies the non-intuitive aspects of otehr models in which the teacher must successfully teach any consistent learner. We prove that any class that can be exactly identified by a deterministic po...

A facial analysis-synthesis framework based on a concise set of local, independently actuated, Coarticulation Regions (CR) is presented for the control of 2D animated characters. CR’s are parameterized by muscle actuations and thereby provide a physically meaningful description of face state that is easily abstracted to higher-level descriptions of facial expression. Independent component analy...