N93 - 1 940 SPACE COMMUNICATION ARTIFICIAL INTELLIGENCE FOR LINK EVALUATION TERMINAL (SCAILET) Anoosh K. Shahidi* Richard F. Schlegelmilch Sverdrup Technology, Inc. The University of Akron Edward J. Petrik Jerry L. Walters NASA, Lewis Research Center NASA, Lewis Research Center the critical programming needs of the end-user. ABSTRACT INTRODUCTION A software application to assist end-users of the high burst rate (HBR) link evaluation terminal A software application to assist end-users of (LET) for satellite communications is being the link evaluation terminal (LET) for satellite developed. The HBR LET system developed at communications is being developed. This software NASA Lewis Research Center is an element of the application incorporates artificial intelligence (AI) Advanced C_ommunications Technology Satellite techniques and will be deployed as an interface to (ACTS) Project. LET. The high burst rate (HBR) LET provides 30 GHz transmitting/20 GHz receiving, 220/110 The HBR LET is divided into seven major Mbps capability for wideband communications subsystems, each with its own expert. technology experiments with the Advanced Programming scripts, test procedures defined by Communications Technology Satellite (ACTS). design engineers, set up the HBR LET system. The HBR LET can monitor and evaluate the These programming scripts are cryptic, hard to integrity of the HBR communications uplink and maintain and require a steep learning curve. These downlink to the ACTS satellite. The uplink HBR scripts were developed by the system engineers transmission is performed by bursting the bit- who will not be available for the end-users of the pattern as a modulated signal to the satellite. The system. HBR LET can determine the bit error rate (BER) under various atmospheric conditions by To increase end-user productivity a friendly interface needs to be added to the system. One comparing the transmitted bit pattern with the received bit pattern. An algoriflun for power possible solution is to provided the user with augmentation will be applied to enhance the adequate documentation to perform the needed system's BER performance at reduced signal tasks. With the complexity of this system the vast amount of documentation needed would be strength caused by adverse conditions. overwhelming and the information would be hard The HBR LET terminal consists of seven major to retrieve. With limited resources, maintenance is another reason for not using this form of subsystems: documentation. •Antenna subsystem • Radio frequency (RF) transmitter An advanced form of interaction is being subsystem explored using current computer techniques. This •RF receiver subsystem application, which incorporates a combination of • Control and performance monitor (C&PM) multirfiedia and artificial intelligence (AI) computer subsystem techniques to provided end-users with an •Local loopback subsystem at RF intelligent interface to the HBR LET system, is • Modulation and BER measurements comprised of an intelligent assistant, intelligent subsystem tutoring, and hypermedia documentation. The •Calibration subsystem intelligent assistant and tutoring systems address 130 PRECEDING PAGE BLAI_K NOT MLMED The C&PM computer controls and monitors requested changes in the system. The changes will all the other subsystems through an IEEE488 then be reflected dynamically on the schematic interface. I-IBR LET experiments with the ACTS diagram. satellite will be initiated by users through the C&PM experiment control and monitor (ECM) The dynamic graphics are implemented software. The ECM software was developed on a using the Choreographer Graphical User Interface Concurrent 3205 minicomputer in FORTRAN, toolkit, developed by GUidance Technologies which provides the end-user with the following Corp. The expert system shell used for this project capabilities: is KAPPA PC developed by Intellicorp Corp. KAPPA PC is a hybrid expert system shell which • Individual instrument control has both a complete object oriented programming • Interactive interface used to communicate system and a rule based expert system. All HBR with the digital ground terminal LET devices are implemented in KAPPA PC •Ability to conduct BER measurements objects. The devices are connected to one another • User-controlled data acquisition using message passing to create a dynamic model of the system. Rules are used to create programming scripts. Programming scripts, defined by the design engineer, set up the HBR LET terminal by programming subsystem devices through IEEE488 MULTIMEDIA DOCUMENTATION interfaces. However, the scripts are difficult to use, require a steep learning curve, are cryptic, and Multimedia is a software package that are hard to maintain. The combination of the applies a combination of text, graphics, voice, and learning curve and the complexities involved with video technologies in a computer application tool. editing the script files may discourage end-users The combination of these technologies provides a from utilizing the full capabilities of the HBR LET more powerful tool than any one medium alone. system. Text and graphics information can then be combined within the application. Similarly, The following SCAILET features will associated voice and video information can be integrated into the application. This module is improve the HBR LET system and enhance the implemented using the ToolBook hypertext shell end-user's ability to perform the experiments: developed by Asymetrix Corp. The documentation for the HBR LET INTELLIGENT ASSISTANT subsystems is being developed by different design engineers. However, the end-user will need to see An intelligent assistant is a software the association among the subsystems. program that will aid the user in operating of the Multimedia allows the user to look at a graphic HBR LET components. Friendly human interfaces image of a schematic diagram, and request written shield the user from the script and complexities of specifications of the components, more detailed the HBR LET system and furthermore aid images, or actual assembly diagrams. Multimedia performing iterative setup tasks. Any intelligent allows the users to follow schematics' links and assistant also contains sufficient information about visit subsystems within the circuitry. Using the HBR LET system to alert the user to erroneous printed documents would be less friendly and actions. require much more time and effort to understand. This module is connected to the intelligent The intelligent assistant uses a personal assistant so the user can access relevant computer to provide a dynamic schematic diagram documentation anytime during system of the overall system . The schematic diagram programming. provides a graphic user interface which serves as a "front-end" to the I-IBR LET system. The user can control the system by interacting with the schematic diagram. An expert system handles 131 FUTURE DIRECTION: INTELLIGENT BIBLIOGRAPHY TUTOR Computer assisted instruction (CAI) is a ° "Using Open Script: ToolBook Software traditional computer based training program which Construction Set for Windows". Asymetrix takes the user through a predetermined set of Corp., Bellevue, Washington 98004. (1990) lessons. The advent of artificial intelligence 2. "KAPPA PC Reference Manual". Intellicorp technology and advances in cognitive psychology Corp., Mountain View, CA (1989). gave rise to intelligent tutoring systems (ITS) as an improvement to CAI. In an ITS environment, the 3. " Choreographer Reference Manual". Guidance curriculum designer determines what concepts the Technologies Corp. (1989) student should learn in a lesson. The student is then taken through subjects to see which concepts he/she is lacking. The program then determines the curriculum depending on the needs of the student. For HBR LET, an initial overview of individual system components is necessary to aid in understanding the complete system. Concepts important to the operation of each HBR LET subsystem will be identified for SCAILET after the multimedia documentation and intelligent assistant tasks are completed. A guided learning process, which incorporates the use of a simulator, will be developed to provide ITS instruction on the operation of the HBR LET system. ACKNOWLEDGMENTS This project is being developed at and funded by the Space Electronics Division of the NASA Lewis Research Center. We would like to thank Mr. Rich Rienhart of Analax Corp., the programmer of the ECM software, for his excellent work and cooperation with the SCAILET team.We would also like to thank the NASA Lewis Research Center ACTS Project Office. *Principle contact: Anoosh K. Shahidi, Sverdrup Technology Inc. Mail Stop SVR-1, 2001 Aerospace Parkway, Brook Park, Ohio 44142 (216) 891-2213 132