This paper studies the complexity of operations on finite automata and the complexity of their decision problems when the alphabet is unary. Let $n$ denote the maximum of the number of states of the input finite automata considered in the corresponding results. The following main results are obtained: (1) Given two unary NFAs recognising $L$ and $H$, respectively, one can decide whether $L \subseteq H$ as well as whether $L = H$ in time $2^{O((n \log n)^{1/3})}$. The previous upper bound on time was $2^{O((n \log n)^{1/2})}$ as given by Chrobak (1986), and this bound was not significantly improved since then. (2) Given two unary UFAs (unambiguous finite automata) recognising $L$ and $H$, respectively, one can determine a UFA recognising $L \cup H$ and a UFA recognising complement of $L$, where these output UFAs have the number of states bounded by a quasipolynomial in $n$. However, in the worst case, a UFA for recognising concatenation of languages recognised by two $n$-state UFAs, uses $2^{Θ((n \log^2 n)^{1/3})}$ states. (3) Given a unary language $L$, if $L$ contains the word of length $k$, then let $L(k)=1$ else let $L(k)=0$. Let $ω_L$ be the $ω$-word $L(0)L(1)\ldots$ and let $\cal L$ be a fixed $ω$-regular language. The last section studies how difficult it is to decide, given an $n$-state UFA or NFA

This paper reports on an ongoing attempt to develop an author-friendly approach to procedural game dialogue generation. Various affordances of the experimental authoring tool Expressionist are appropriated to allow non-computer scientist authors to design virtual characters' discourse and reasoning potential. The paper describes how the Hammurabi game project makes use of metadata-driven context free grammars to author virtual characters that can generate not only discourse but also context-relevant decisions. The author-friendliness and generativity of the approach is discussed.

The wave of a knowledge economy drives today's education to equip students with knowledge building abilities. While collaborative learning has been proven to be an effective constructivist pedagogy, it is difficult to elicit, coordinate, and capture the corresponding knowledge construction process. The situation becomes more challenging when learning is conducted in a distributed environment in which the participants are scattered in different geographical locations. In this paper, we depict the theories, architecture, applications, and analysis of a Web-based computer-supported collaborative learning and knowledge-building system called Knowledge Community (KC), which currently serves a series of 3I (interdisciplinary, interschool, and international) Project Learning activities with more than 10 000 students and teachers participating globally. We also describe the corresponding 3I Project Learning model, a novel technology-enabled pedagogy in which learners perform collaborative, comparative study projects with peers from other countries. Technologically, KC is the use of Web technologies to provide a collaborative learning environment. Pedagogically, KC with its embedded learning theories has created a new learning culture that meets the demands of knowledge economy.