An essential cycle on a surface is a simple cycle that cannot be continuously deformed to a point or a single boundary. We describe algorithms to compute the shortest essential cycle in an orientable combinatorial surface in O(n2 log n) time, or in O(n log n) time when both the genus and number of boundaries are fixed. Our results correct an error in a paper of Erickson and Har-Peled [DCG 2004].

Nowadays, web archives preserve the history of large portions of the web. As medias are shifting from printed to digital editions, accessing these huge information sources is drawing increasingly more attention from national and international institutions, as well as from the research community. These collections are intrinsically big, leading to index files that do not fit into the memory and ...

We argue that traditional sequencing technology developed in the field of intelligent tutoring systems could find an immediate place in largescale web-based education. This paper discusses two models that have been explored by the authors – the dynamic course generation system DCG and the concept-based course maintenance system CoCoA. DCG includes components for domain authoring and for automat...

Existing captcha solutions on the Internet are a major source of user frustration. Game captchas are an interesting and, to date, little-studied approach claiming to make captcha solving a fun activity for the users. One broad form of such captchas – called Dynamic Cognitive Game (DCG) captchas – challenge the user to perform a game-like cognitive task interacting with a series of dynamic image...

Linear NDCG is used for measuring the performance of the Web content quality assessment in ECML/PKDD Discovery Challenge 2010. In this paper, we will prove that the DCG error equals a new pair-wise loss.

We study the syntactic complexity of finite/cofinite, definite and reverse definite languages. The syntactic complexity of a class of languages is defined as the maximal size of syntactic semigroups of languages from the class, taken as a function of the state complexity n of the languages. We prove that (n − 1)! is a tight upper bound for finite/cofinite languages and that it can be reached on...

this study investigated the relative effects of deductive and inductive form-focused instruction (ffi) on the acquisition of 4 non-generic definite article uses(cultural, situational, structural, and textual) as assessed by explicit and implicit outcome measures. the tests utilized to assess efl learners' acquisition of definite article uses were timed and untimed grammaticality judgment tests....