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Tribological Studies of Microelectromechanical Systems

Dugger, Michael T.

Understanding and controlling friction in micromachine interfaces is critical to the reliability and operational efficiency of microelectromechanical systems (MEMS). The relatively high adhesion forces and friction forces encountered in these devices often present major obstacles to the design of reliable MEMS devices. Using surface micromachining, arrays of microstructures are being designed and tested to examine the adhesion characteristics, static friction behavior, and dynamic friction response. Emphasis is also being given to the control and actuation of the test structures and the modeling of the dynamic response and contact mechanics at the interface. Specifically, the purpose of the research is to fabricate and test MEMS devices in order to obtain insight into the effect of surface topography, material properties, surface chemical state, environmental conditions, and contact load on the static and dynamic characteristics of the contact interface.

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TYPE SAND Report YEAR 2008
DOIDOIOSTIOSTI

A survey of routing techniques in store-and-forward and wormhole interconnects

Lee, David S.

This paper presents an overview of algorithms for directing messages through networks of varying topology. These are commonly referred to as routing algorithms in the literature that is presented. In addition to providing background on networking terminology and router basics, the paper explains the issues of deadlock and livelock as they apply to routing. After this, there is a discussion of routing algorithms for both store-and-forward and wormhole-switched networks. The paper covers both algorithms that do and do not adapt to conditions in the network. Techniques targeting structured as well as irregular topologies are discussed. Following this, strategies for routing in the presence of faulty nodes and links in the network are described.

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TYPE SAND Report YEAR 2008
DOIOSTI

Network topology analysis

Lee, David S.; Kalb, Jeffrey L.

Emerging high-bandwidth, low-latency network technology has made network-based architectures both feasible and potentially desirable for use in satellite payload architectures. The selection of network topology is a critical component when developing these multi-node or multi-point architectures. This study examines network topologies and their effect on overall network performance. Numerous topologies were reviewed against a number of performance, reliability, and cost metrics. This document identifies a handful of good network topologies for satellite applications and the metrics used to justify them as such. Since often multiple topologies will meet the requirements of the satellite payload architecture under development, the choice of network topology is not easy, and in the end the choice of topology is influenced by both the design characteristics and requirements of the overall system and the experience of the developer.

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TYPE SAND Report YEAR 2008
DOIOSTI
Results 77351–77375 of 96,771
Results 77351–77375 of 96,771