Tony Mason

John Levine

Doug Brown

lex & yacc

qmail has quietly become one of the most widely used applications on the Internet today. It's powerful enough to handle mail for systems with millions of users--Like Yahoo! Mail and Hotmail, while remaining compact and manageable enough for the smallest Unix- and Linux-based PC systems. Its component design makes it easy to extend and customize while keeping its key functions secure, so it's no wonder that adoption of qmail continues at a rapid pace. The downside? Apparently none. Except that qmail's unique design can be disorienting to those familiar with other popular MTAs (Mail Transfer Agents). If you're coming from sendmail, for instance, you might have trouble recasting your problems and solutions in qmail terms. qmail first helps you establish a "qmail frame of mind," then explores the installation, configuration, administration, and extension of this powerful MTA. Whether you're installing from scratch or managing mailing lists with thousands of users, qmail provides detailed information about how to make qmail do precisely what you want qmail concentrates on common tasks like moving a sendmail setup to qmail, or setting up a "POP toaster," a system that provides mail service to a large number of users on other computers sending and retrieving mail remotely. The book also fills crucial gaps in existing documentation, detailing exactly what the core qmail software does. Topics covered include: Installation and configuration, including patching qmail Moving from sendmail to qmail Handling locally and remotely originated messages Managing virtual domains Logging qmail activity Tuning qmail performance Running multiple copies of qmail on the same computer Mailing list setup and management Integrating the qmail MTA with POP and IMAP delivery Filtering out spam and viruses If you need to manage mailing lists, large volumes of mail, or simply find sendmail and other MTAs too complicated, qmail may be exactly what's called for. Our new guide, qmail, will provide the guidance you need to build an email infrastructure that performs well, makes sense, and is easy to maintain.

Qmail

This book shows you how to use two Unix utilities, lex andyacc, in program development. These tools help programmers build compilers and interpreters, but they also have a wider range of applications.The second edition contains completely revised tutorial sections for novice users and reference sections for advanced users. This edition is twice the size of the first and has an expanded index.The following material has been added: Each utility is explained in a chapter that covers basic usage and simple, stand-alone applications How to implement a full SQL grammar, with full sample code Major MS-DOS and Unix versions of lex and yacc are explored in depth, including AT&T lex and yacc, Berkeley yacc, Berkeley/GNU Flex, GNU Bison, MKS lex andyacc, and Abraxas PCYACC

Georgios N. Yannakakis

John Hallam

Which features of a computer game contribute to the player's enjoyment of it? How can we automatically generate interesting and satisfying playing experiences for a given game? These are the two key questions addressed in this dissertation. Player satisfaction in computer games depends on a variety of factors; here the focus is on the contribution of the behaviour and strategy of game opponents in predator/prey games. A quantitative metric of the 'interestingness' of opponent behaviours is defined based on qualitative considerations of what is enjoyable in such games, and a mathematical formulation grounded in observable data is derived. Using this metric, neural-network opponent controllers are evolved for dynamic game environments where limited inter-agent communication is used to drive spatial coordination of opponent teams. Given the complexity of the predator task, cooperative team behaviours are investigated. Initial candidates are generated using off-line learning procedures operating on minimal neural controllers with the aim of maximising opponent performance. These example controllers are then adapted using on-line (i.e. during play) learning techniques to yield opponents that provide games of high interest. The on-line learning methodology is evaluated using two dissimilar predator/prey games with a number of different computer player strategies. It exhibits generality across the two game test-beds and robustness to changes of player, initial opponent controller selected, and complexity of the game field. The interest metric is also evaluated by comparison with human judgement of game satisfaction in an experimental survey. A statistically significant number of players were asked to rank game experiences with a test-bed game using perceived interestingness and their ranking was compared with that of the proposed interest metric. The results show that the interest metric is consistent with human judgement of game satisfaction. Finally, the generality, limitations and potential of the proposed methodology and techniques are discussed, and other factors affecting the player's satisfaction, such as the player's own strategy, are briefly considered. Future directions building on the work described herein are presented and discussed.

John Levine

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