HADES

 

HADES (Haskins Analysis Display and Experiment System) refers to a family of computer programs that was developed at Haskins Laboratories (Rubin, 1995) to provide for the display and analysis of multiple channel physiological, speech, and other sampled data in an experimental context. HADES has become the main system for signal display and analysis at Haskins and is also being used at a number of academic research sites around the world. In general, HADES is used in two ways. The principal use of the system is for the display and analysis of physiological signals. These signals can be acquired from a variety of sources, including the EMMA magnetometer hardware. The second main use of HADES is for automated editing, labelling, and analysis of speech signals.

Three main functions lie at the heart of the HADES system: display, manipulation and analysis of sampled data. Signal vectors are separated from display tools to allow for multiple views of the same data set. Data sets of up to 64 channels, supporting mixed sampling rates, can be handled. A variety of display and analysis tools are available to the user. Some of these tools are fairly general for the types of signals being used. Examples of standard displays include simple time waveform plots, overlayed multiple waveform plots, spectrograms, spectral cross-sections, waterfalls, etc. For analysis, we provide standard Fast Fourier Transform (FFT) and Linear Predictive Coding (LPC) analyses. Other tools are more specific to the research environment at Haskins Laboratories and have been (or are being) developed in the context of the needs of our own specific research environment, in particular the use of an electromagnetic midsagittal articulometer for acquiring information about speech production (Perkell). We have found, however, that most of the tools and primitives that we have developed are of use to researchers outside of Haskins Laboratories. Less standard displays and analyses include phase and lissajous plots, TIFF, displays, vocal tract pellet animation, event marking, centroid calculations, etc.

The most significant feature of HADES is the incorporation of a procedural language (known as SPIEL). SPIEL permits the creation and customization of specialized analysis procedures that can be stored as text files, edited, etc., and are similar to functions and subroutines in programming languages like C and FORTRAN. SPIEL procedures are either interpreted from command-line entry or from text stored in ASCII command files. All the data displayed by or stored in HADES is accessible to the language as variables, and most operations of the programs are available as commands. This procedural language lets users automate routine operations, such as labelling and removing stretches of silence, and permits simple processing/analysis, within individual signals and across sets of separate signals.

The HADES system was designed to run on VAX computers, using the VMS operating system. The development of HADES on a VAX platform combines specific configuration requirements at Haskins Laboratories along with the need for an analysis package that would run on engineering workstations. In a limited form, the program will run on any terminal connected to a VAX and can also be accessed via Ethernet from microcomputer terminals that support either Tektronix 4010/4014 graphics of XWindows/Motif emulation. A variety of flavors of HADES exist. These are related, again, to the historical development of the system along with the changing workstation graphical user interface (GUI) standards. At present, HADES exists in two main flavors: HADES, which runs on VAX VMS workstations that support UIS graphics; and XHADES, which runs on VAX VMS workstations that support XWindows graphics. A third version of HADES, called MHADES, is presently under development. MHADES is designed for full compatability with the Motif user interface. Finally, AHADES is in the planning stages. AHADES is a version of MHADES that will run on Digital's newer Alpha (DEC AXP) platform.

Rubin, Philip E. (1995). HADES: A Case Study of the Development of a Signal Analysis System. In R. Bennett, S. L. Greenspan & A. Syrdal (Eds.), Behavioral Aspects of Speech Technology: Theory and Applications. Elsevier.

Rubin, Philip E. and Löfqvist, Anders (1995). HADES (Haskins Analysis Display and Experiment System). Haskins Laboratories Status Report, submitted.
(This is a long (81 pages) document in PDF format).

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