Experimental Demonstration Of A New Concept Of Drag Reduction And Thermal Protection For Hypersonic Vehicles

A new idea of drag reduction and thermal protection for hypersonic vehicles is proposed based on the combination of a physical spike and lateral jets for shock-reconstruction. The spike recasts the bow shock in front of a blunt body into a conical shock, and the lateral jets work to protect the spike tip from overheating and to push the conical shock away from the blunt body when a pitching angle exists during flight. Experiments are conducted in a hypersonic wind tunnel at a nominal Mach number of 6. It is demonstrated that the shock/shock interaction on the blunt body is avoided due to injection and the peak pressure at the reattachment point is reduced by 70% under a 4A degrees attack angle.

coconceptmap: a system for collaborative concept mapping

Concept mapping is a technique for visualizing the relationships between different concepts, and collaborative concept mapping is used to model knowledge and transfer expert knowledge. Because of lacking some features,existing systems can’t support collaborative concept mapping effectively. In this paper, we analysis the collaborative concept mapping process according to the theory of distributed cognition, and argue the functions effective systems ought to include. A collaborative concept mapping system should have the following features: visualization of concept map, flexible collaboration style,supporting natural interaction, knowledge management and history management. Furthermore, we describe every feature in details. Finally,a prototype system has been built to fully explore the above technologies.

structuring and manipulating hand-drawn concept maps

Concept maps are an important tool to knowledge organization,representation, and sharing. Most current concept map tools do not provide full support for hand-drawn concept map creation and manipulation, largely due to the lack of methods to recognize hand-drawn concept maps. This paper proposes a structure recognition method. Our algorithm can extract node blocks and link blocks of a hand-drawn concept map by combining dynamic programming and graph partitioning and then build a concept-map structure by relating extracted nodes and links. We also introduce structure-based intelligent manipulation technique of hand-drawn concept maps. Evaluation shows that our method has high structure recognition accuracy in real time, and the intelligent manipulation technique is efficient and effective.

The mean value concept in mono-linear regression of multi-variables and its application to trace studies in geosciences

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