1996 Working Papers
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Item Melody transcription for interactive applications(Working Paper, 1996-12) McNab, Rodger J.; Smith, Lloyd A.A melody transcription system has been developed to support interactive music applications. The system accepts monophonic voice input ranging from F2 (87 HZ) to G5 (784 HZ) and tracks the frequency, displaying the result in common music notation. Notes are segmented using adaptive thresholds operating on the signal's amplitude; users are required to separate notes using a stop consonant. The frequency resolution of the system is ±4 cents. Frequencies are internally represented by their distance in cents above MIDI note 0 (8.176 Hz); this allows accurate musical pitch labeling when a note is slightly sharp or flat, and supports a simple method of dynamically adapting the system's tuning to the user's singing. The system was evaluated by transcribing 100 recorded melodies-10 tunes, each sung by 5 male and 5 female singers-comprising approximately 5000 notes. The test data was transcribed in 2.8% of recorded time. Transcription error was 11.4%, with incorrect note segmentation accounting for virtually all errors. Error rate was highly dependent on the singer, with one group of four singers having error rates ranging from 3% to 5%, error over the remaining 6 singers ranged from 11% to 23%.Item Selecting multiway splits in decision trees(Working Paper, 1996-12) Frank, Eibe; Witten, Ian H.Decision trees in which numeric attributes are split several ways are more comprehensible than the usual binary trees because attributes rarely appear more than once in any path from root to leaf. There are efficient algorithms for finding the optimal multiway split for a numeric attribute, given the number of intervals in which it is to be divided. The problem we tackle is how to choose this number in order to obtain small, accurate trees.Item Reconstructing Minard's graphic with the relational visualisation notation(Working Paper, 1996-12) Humphrey, Matthew C.Richly expressive information visualisations are difficult to design and rarely found. Few software tools can generate multi-dimensional visualisations at all, let alone incorporate artistic detail. The Relational Visualisation Toolkit is a new system for specifying highly expressive graphical representations of data without traditional programming. We seek to discover the accessible power of this notation-both its graphical expressiveness and its ease of use. Towards this end we have used the system to design and reconstruct Minard's Visualisation of Napoleon's Russian campaign of 1812. The resulting image is very similar to the original, and the design is straightforward to construct. Furthermore, the design is sufficiently general to be able to visualise Hitler's WWII defeat before Moscow.Item OzCHI'96 Workshop on the Next Generation of CSCW Systems(Working Paper, 1996-11-25) Grundy, John C.This is the Proceedings of the OZCHI'96 Workshop on the Next Generation of CSCW Systems. Thanks must go to Andy Cockburn for inspiring the name of the workshop and thus giving it a (general) theme! The idea for this workshop grew out of discussions with John Venable concerning the Next Generation of CASE Tools workshop which he'd attended in 1995 and 1996. With CSCW research becoming more prominent within the CHI community in Australasia, it seemed a good opportunity to get people together at OZCHI'96 who share this interest. Focusing the workshop on next-generation CSCW system issues produced paper submissions which explored very diverse areas of CSCW, but which all share a common thread of "Where do we go from here?", and, perhaps even more importantly "Why should be doing this?".Item Teaching students to critically evaluate the quality of Internet research resources(Working Paper, 1996-11) Cunningham, Sally JoThe Internet offers a host of high-quality research material in computer science-and, unfortunately, some very low quality resources as well. As part of learning the research process, students should be taught to critically evaluate the quality of all documents that they use. This paper discusses the application of document evaluation criteria to WWW resources, and describes activities for including quality evaluation in a course on research methods.