We report an observation of essentially full spatial coherence in a high average power soft-x-ray laser. Rapid coherence buildup due to strong refractive antiguiding in a long plasma column is experimentally demonstra...
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We report an observation of essentially full spatial coherence in a high average power soft-x-ray laser. Rapid coherence buildup due to strong refractive antiguiding in a long plasma column is experimentally demonstrated. This allows the generation of fully coherent, milliwatt-level average power soft-x-ray radiation by a tabletop device. The peak brightness of this laser reaches 2×1025photonss−1mm−2mrad−2 within 0.01% spectral bandwidth, making it one of the brightest soft-x-ray sources available.
A micro-mechanical switch has been designed and fabricated in which the bounce after contact closure has been reduced by using mechanical momentum transfer and magnetic damping, while maintaining high contact forces. ...
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ISBN:
(纸本)0780359984
A micro-mechanical switch has been designed and fabricated in which the bounce after contact closure has been reduced by using mechanical momentum transfer and magnetic damping, while maintaining high contact forces. The period of chatter has been reduced from 1.5 milliseconds to less than 0.3 milliseconds, while the switching speed is 5 millisecond. The switch has been fabricated using Permalloy (78% Ni and 22% Fe) and copper. The LIGA process was used in the fabrication of the switch. An improved copper process allowed the fabrication of high aspect ratio (20:1) structures which were subsequently freed and assembled.
Routing in ad-hoc networks is a difficult challenge that involves a tradeoff between efficiency and responsiveness. An ad-hoc network routing algorithm must adapt rapidly enough to topology changes to meet the perform...
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ISBN:
(纸本)0769510922
Routing in ad-hoc networks is a difficult challenge that involves a tradeoff between efficiency and responsiveness. An ad-hoc network routing algorithm must adapt rapidly enough to topology changes to meet the performance demands of users, without over-utilizing network resources. This paper presents the (/spl alpha/,t) cluster framework which utilizes a distributed dynamic clustering strategy to organize nodes into clusters in which the probability of path failure due to node movement can be bounded over time. The objective of the clustering strategy is to achieve scalability and support robust, efficient routing subject to a wide range of mobility rates. Based on the (/spl alpha/,t) cluster scheme, routes within clusters are maintained on a proactive basis, whereas hierarchical routing between clusters is managed on a demand-basis. Simulation results show that the cluster organization can be effectively adapted to node mobility and that routing is both more robust and efficient than routing in fully proactive, reactive or fixed-hybrid schemes.
We examine the feasibility of designing a gyroscope-free inertial navigation system (INS) that uses only accelerometers to compute the linear and angular motions of a rigid body. The accelerometer output equation is d...
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We examine the feasibility of designing a gyroscope-free inertial navigation system (INS) that uses only accelerometers to compute the linear and angular motions of a rigid body. The accelerometer output equation is derived to relate the linear and angular motions of a rigid body relative to a fixed inertial frame. A sufficient condition is given to determine if a configuration of accelerometers is feasible. If the condition is satisfied, the angular and linear motions can be computed separately using two decoupled equations of an input-output (I/O) dynamical system; a state equation for angular velocity and an output equation for linear acceleration. This simple computation scheme is derived from the corresponding dynamical system equations for a special cube configuration for which the angular acceleration is expressed as a linear combination of the accelerometer outputs.
We present a technique for reconstructing facial movies, given a small number of real images and a few parameters for the in-between images. The parameters can be automatically extracted by a tracking system. This sch...
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ISBN:
(纸本)0769510744
We present a technique for reconstructing facial movies, given a small number of real images and a few parameters for the in-between images. The parameters can be automatically extracted by a tracking system. This scheme can also be used for creating realistic facial animations and for compression of facial movies. The in-between images are produced without ever generating a 3D model of the face. Since facial motions due to expressions are not well defined mathematically our approach is based on utilizing image patterns in facial optical flow. These patterns were revealed by an empirical study which analyzed and compared image motion patterns in facial expressions.
In this paper we present a case study of our candidate design for the user-interface of a wireless vital-signs monitor. We reflect on our design of the user-interface, and relate our design experience to theories of a...
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ISBN:
(纸本)9781450373265
In this paper we present a case study of our candidate design for the user-interface of a wireless vital-signs monitor. We reflect on our design of the user-interface, and relate our design experience to theories of artefact design, evaluating from this case study how the theories apply to the broader design context of design for AR. Theories of 'good design' in artefact design literature do not unilaterally apply to the design for an augmented reality device. In many cases, design in AR fields requires the designer to create new cultural conventions by virtue of the fact that the designer is immersing the user in an unfamiliar environment. Thus, the designer is often unable to utilise affordances and existing cultural conventions because the functions and/or use of the object expands the environment in which affordances and cultural conventions currently have meaning. Copyright 2000 ACM.
Signals from 12 soprano and mezzo-soprano singers are analyzed with the modal distribution, a high-resolution time-frequency analysis method, to obtain measures of instantaneous amplitude and frequency of the signals...
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This paper presents the development of a plane wave tube with variable mean flow for static and dynamic calibration of shear stress sensors. The static response is obtained via a variable mean flow and the dynamic cal...
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This paper presents a comprehensive model of a circular-diaphragm piezoresistive microphone. The structural characteristics of the diaphragm are developed as a function of both in-plane stress and transverse loading. ...
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We classify an input space according to the outputs of a real-valued function. The function is not given, but rather examples of the function. We contribute a consistent classifier that avoids the unnecessary complexi...
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ISBN:
(纸本)0262122413
We classify an input space according to the outputs of a real-valued function. The function is not given, but rather examples of the function. We contribute a consistent classifier that avoids the unnecessary complexity of estimating the function.
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