An analytical solution to optimize satellite communication systems is derived. The network is starshaped and a central hub station is connected to VSATs (Very Small Aperture Terminals) via a communication satellite. The traffic is thin and a simplified VSAT cost model is used. The system cost including a satellite transponder and VSATs are minimized by optimizing the size of the antennae.
This paper presents design problems of a ramengine combustor which is supposed to operate in the flight speed range between Mach numbers 3 to 5. Two types of model combustors were tested. Main aims were to examine their flame holding ability and to measure the pollutant emission along the predicted operational conditions. It was found that both combustors, satisfying required pressure loss, could not sustain stable flame at flight Mach number 3 condition. The improvement strategy is discussed. NOx emission was measured at temperatures ranging up to 1050K in electrically heated air. An experimentally derived correlation was used to predict NOx emission levels for the cruise flight condition of the engine. Present results lead to the conclusion that homogeneous combustion is a prerequisite for improving the combustor performance as well as for reducing NOx emission.
Visual design of the user interfaces is performed with the design principles of the graphical user interfaces (GUI). The design process of the GUI is consist of determining the functions based on user's requests and interpreting the design principles to implement the GUI by using a specific graphic widget, that is the OSF/Motif. The users focused on this paper are software engineers to develop missile simulation systems. Most primitive functions to make programming and testing the simulation programs are classified into two groups: one is associated with editing and compiling the source codes, and the other is associated with visualizing the simulation results. The design principles deduced from usability inspection are applied to decide hierarchy and layout of the menus of functions. Details of the layout should be discussed with the layout guidlines of the OSF/Motif widget. The author built the system with the GUI to develop the missile simulation programs, and shows an example of utilizing the system to develop a missile trajectory simulation program.