Heat shield characterization: Outer planet atmospheric entry probe

A full scale carbon phenolic heat shield was fabricated for the Outer Planet Probe in order to demonstrate the feasibility of molding large carbon phenolic parts with a new fabrication processing method (multistep). The sphere-cone heat shield was molded as an integral unit with the nose cap plies configured into a double inverse chevron shape to achieve the desired ply orientation. The fabrication activity was successful and the feasibility of the multistep processing technology was established. Delaminations or unbonded plies were visible on the heat shield and resulted from excessive loss of resin and lack of sufficient pressure applied on the part during the curing cycle. A comprehensive heat shield characterization test program was conducted, including: nondestructive tests with the full scale heat shield and thermal and mechanical property tests with small test specimen

Multi–criteria Route Planning in Bus Network

Part 7: NetworkingInternational audienceIn this paper, we consider the problem of finding itineraries in bus networks under multiple independent optimization criteria, namely arrival time at destination and number of transfers. It is also allowed to walk from one stop to another if the two stops are located within a small distance. A time–dependent model is proposed to solve this problem. While focusing on the network where the size of the Pareto set in the multi–criteria shortest path problem might grow exponentially, we develop an efficient algorithm with its speed–up techniques. An evaluation on the qualities of found paths and the empirical results of different implementations are given. The results show that the allowance of walking shortcuts between nearby stops gives a better route planning

Engineering Route Planning Algorithms

Algorithms for route planning in transportation networks have recently undergone a rapid development, leading to methods that are up to three million times faster than Dijkstra’s algorithm. We give an overview of the techniques enabling this development and point out frontiers of ongoing research on more challenging variants of the problem that include dynamically changing networks, time-dependent routing, and flexible objective functions