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  MIDAS 3.0
  Although application directed work with the existing software comprises half of the program's funding, a major effort to rearchitect the MIDAS system is also underway. The goals driving this redesign include decreasing development time for new scenarios (from several months to one or two weeks), increasing the efficiency of the running system (from around 50 times real- time to near real- time), facilitating the process of replacing cognitive and perceptual models (from weeks to days), and expanding the functionality of the system as detailed below.

Presently, MIDAS is implemented in a combination of C/C++ and LISP, with the human performance elements being largely LISP- based. As a result, supporting the interaction of modules in different languages and trying to map design concepts uniformly across very different programming paradigms (e.g., the notion of agent), has proved difficult. In addition, while it began with a fairly rigorous design process, over the years MIDAS has acquired a number of idiosyncratic and hard-wired features, simply due to time constraints and the nature of complex software evolution. The resulting system is difficult to learn, maintain, and modify. There was also a desire to update the human operator model - in particular to account for more widely accepted views on human information processing and its likely underlying architecture.

For these reasons, a research phase is underway with the goal of redesigning MIDAS using object-oriented techniques and implementing the system entirely in C++. While human factors analysis will remain the key purpose of the system, the new design was not intended to map directly to the existing version of MIDAS. Further, the described applications and other research in human modeling demanded expanded functionality for the system in several areas. These included enhancements of the human operator model to encompass more complete notions of attention and working memory, as well as support for modeling multiple human operators and their interactions. Further emphasis also needed to be placed on the human-computer interface of the system, as well as adding an explicit simulation analysis environment to enable a more complete examination of simulation results.

The approach taken in MIDAS' redesign is object-oriented rapid prototyping. Initial design efforts produced a high-level system architecture with the following elements: a domain model supporting components necessary for running a simulation; a graphics system to enable simulation visualization; an interface for end user specification of the target domain models; a simulation system for controlling the simulation and collecting data therefrom; and a results analysis system for examining simulation data after it has been collected.

MIDAS Interface Screenshot ImageThe latest and most current version of MIDAS integrates the Apex architecture into the MIDAS architecture. Apex: MIDAS is a tool for rapidly developing 3-D models and simulations of human performance in complex operational environments, for example, modeling how an astronaut would use a new display interface. Apex is an autonomy architecture that provides the decision-making model for the simulated human (operator) in MIDAS. Procedural knowledge for each operator is encoded in Apex's Procedure Description Language (PDL). As the MIDAS simulation runs, sensory events (visual and auditory) are passed to Apex, which responds by invoking behaviors in the operator as specified in its active procedures. Apex also includes Sherpa, a visualization tool that provides detailed views of the operator's procedure execution status and event history with task timelines.

MIDAS is now an agent-based architecture that includes additional multitasking and scheduling capabilities in response to environmental and other human-related constraints. This version of MIDAS is currently being applied to Crew Exploration Vehicle simulations to validly replicate human-in-the-loop performance conducted in the ISIS laboratory. This version of MIDAS is a 3-D rapid prototyping human performance modeling and simulation environment that produces quantitative predictions of human-system safety (resource use and allocation). MIDAS with Apex supports the design of automation, crew stations and operating procedures, and reduces design cycle time. MIDAS/Apex adheres to a both top-down and bottom-up modeling approaches through its integrated structure. This integrated structure allows generation of emergent behaviors. In addition, it is packaged into a consistent integrated computer desktop development environment. This desktop environment allows users to enter procedures, populate the environment, examine run-time visualization, analyze workload (6-channel), analyze situation awareness, performance error predictions, and conduct safety evaluations.  MIDAS/Apex provides a number of augmentation to the existing MIDAS architecture. MIDAS/Apex provides advanced decision-making support for enabling multi-tasking and resource scheduling models; a unified query system that supports event, state, and temporal reasoning; allows fast time simulation data to be used from an outside source; permits use of visualization tools to increase system safety.
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