Propellant-powered actuator for gas generators

Hydrazine operated monopropellant generators are used for spacecraft rocket engines and propellant pressurization systems. Measured work output of monopropellant actuators compares favorably with output of squib-type actuators

Ferromagnetic-fluid logic devices

Logic element switches flows of low pressure process control fluid in fluidics assemblies. Device operates both electrically and fluidically and is controlled by passing permanent magnet or electromagnet over elements, thus providing proximity switching functions

Selected Issues of Design and Implementation od Decision Support Systems

The paper presents selected issues related to design and implementation of model based Decision Support Systems (DSS). For over ten years the SDS Program has been involved in cooperation with various projects at IIASA and in collaborating research institutes. This cooperation has resulted in the development of many DSS, which in turn stimulated research on the theory and methodology of decision analysis. An overview of selected DDS developed within the cooperation with IIASA is presented. Different concepts of DSS are briefly discussed and one specific type of DSS, namely model based, aspiration-led DSS is characterized. Finally, selected problems of designing and implementation of a DSS are discussed in more detail. A short description of software packages developed within the cooperation with the MDA Project is provided. The paper also gives a short summary of recent activities of the Methodology of Decision Analysis Project and of the DSS software available from the MDA Project

A Structured Modeling Technology

This paper presents the methodological background and implementation of a structured modeling environment developed to meet the requirements of modeling activities undertaken to support intergovernmental negotiations aimed at improving European air quality. Although the motivation for the reported work came from the actual complex application presented in the paper, the actual scope of the paper covers a wide range of issues related to model-based decision- making support. The paper starts with a summary of the context of modeling composed of: the role of models in decision-making support; modeling paradigms; and state-of-the-art aspects of modeling complex problems. The modeling process is then characterized, and the requirement analysis for implementation of structured modeling is specified. The main part of the paper presents the structured modeling technology which was developed to support the implementation of the structured modeling principles for modeling complex problems

Implementation of an Algorithm for Scaling Matrices and Other Programs Useful in Linear Programming

Matrix scaling is an operation in which the rows and columns of a matrix are multiplied by positive scalars such that the elements of the scaled matrix are similar in absolute magnitude. This can be very important when dealing with models in which matrix elements can take a wide range of values, especially since certain mathematical codes, such as MINOS, require that the absolute values of all non-zero elements should be "reasonably" close to one. This paper describes the implementation of an optimal scaling method proposed by Curtis and Reid. The algorithm is outlined and a users' guide to the program implemented on the VAX at IIASA is given. (The scaling algorithm has been linked to the MINOS package at IIASA by Zenon Fortuna, who has also developed a rescaling routine linked to this package.) Two other programs useful in linear programming are also described: the first is designed to print out a matrix by rows, and also gives diagnostic aid; the second makes it possible to merge up to five LP models into one, generating a resultant MPSX file that may be used to solve multicriteria problems