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排序方式: 共有987条查询结果,搜索用时 15 毫秒
81.
In this paper, we study the problem of reconstruction of a high-resolution (HR) image from several blurred low-resolution (LR) image frames in medium field. The image frames consist of blurred, decimated, and noisy versions of a HR image. The HR image is modeled as a Markov random field (MRF), and a maximum a posteriori (MAP) estimation technique is used for the restoration. We show that with the periodic boundary condition, a HR image can be restored efficiently by using fast Fourier transforms. We also apply the preconditioned conjugate gradient method to restore HR images in the aperiodic boundary condition. Computer simulations are given to illustrate the effectiveness of the proposed approach. This research was conducted with support from the Army Research Office Grant DAAD 19-03-1-0261 and the National Science Foundation Grant CCF-0429481. Research supported in part by RGC Grant Nos. 7130/02P, 7046/03P, 7035/04P and 7035/04P and FRG/04-05/II-51.  相似文献   
82.
In this paper, we seek to provide a systematic anti-windup control synthesis approach for systems with actuator saturation within a linear parameter-varying (LPV) design framework. The closed-loop induced L2 gain control problem is considered. Different from conventional two-step anti-windup design approaches, the proposed scheme directly utilizes saturation indicator parameters to schedule accordingly the parameter-varying controller. Hence, the synthesis conditions are formulated in terms of linear matrix inequalities (LMIs) that can be solved very efficiently. The resulting gain-scheduled controller is non-linear in general and would lead to graceful performance degradation in the presence of actuator saturation non-linearities and linear performance recovery. An aircraft longitudinal dynamics control problem with two input saturation non-linearities is used to demonstrate the effectiveness of the proposed LPV anti-windup scheme.  相似文献   
83.
This paper considers the problem of output feedback trajectory tracking with a unicycle mobile robot system. A state-feedback controller for the non-linear error dynamics of the robot is combined with an observer that estimates the orientation error based on available trajectory information and measurement of the position coordinates. A stability analysis, derivation and implementation of the resulting controller is given and tested on an experimental mobile robot.  相似文献   
84.
Andy Gryc 《软件》2010,(1):44-45
智能屏幕人机界面的开发人员通过使用闪存和C/C++组件,使产品达到了工业级的可靠性和实时性能。楼宇自动化系统的设计便是一个例子。  相似文献   
85.
86.
Undocumented assumptions are often the cause of serious software system failure. Thus, to reduce such failures, developers must become better at discovering and documenting their assumptions. In this article, we focus on common categories of assumptions in software, discuss methods for recognizing when developers are making them, and recommend techniques for documenting them.  相似文献   
87.
GaAs MESFETs with novel lowly-doped drain structures have been developed utilizing molecular implants of silicon trifluoride. Short-channel effects in the 1/4 μm enhancement- and depletion-mode transistors have been suppressed with drain-induced barrier height lowering of less than 70 mV/V and pinch-off voltage shifts of less than 220 mV as the gate length was scaled from 1.0 to 1/4 μm. The 3-terminal breakdown, the transconductance to output conductance ratio, and the unity current gain, cut-off frequency were simultaneously optimized. The E-mode device possessed breakdown of >10 V, Gm · Rds > 9.5, Ft > 55 GHz, and nominal on-resistance of 2.1 Ω mm while the D-mode device had breakdown >10 V, Gm · Rds > 6.0, Ft > 45 GHz, and nominal on-resistance of 1.9 Ω mm. These optimized transistors enabled the realization of a variety of low-power digital and high-power mixed signal circuits, using 3-level source-coupled transistor and common-mode logic, such as laser and electro-optic drivers, highly integrated transceivers, multiplexers, demultiplexers, and clock data recover circuits.  相似文献   
88.
Self‐help has been a neglected aspect of housing provision in industrialised nations, yet in many locations it accounts for a significant share of new production and can contribute to improved housing circumstances for those whose housing need is not too severe. This paper discusses self‐help housing provision in Atlantic Canada and argues that it reduces the profitability of the residential construction industry and for this and other reasons, self‐help is likely to continue as a major form of production. This paper also evaluates the impact on self‐help of several housing policy options.  相似文献   
89.
In Minimum Error Rate Training (MERT), Bleu is often used as the error function, despite the fact that it has been shown to have a lower correlation with human judgment than other metrics such as Meteor and Ter. In this paper, we present empirical results in which parameters tuned on Bleu may lead to sub-optimal Bleu scores under certain data conditions. Such scores can be improved significantly by tuning on an entirely different metric altogether, e.g. Meteor, by 0.0082 Bleu or 3.38% relative improvement on the WMT08 English–French data. We analyze the influence of the number of references and choice of metrics on the result of MERT and experiment on different data sets. We show the problems of tuning on a metric that is not designed for the single reference scenario and point out some possible solutions.  相似文献   
90.
Andy  Julie Plata 《数码印刷》2008,(12):27-29
Andy:大家好,我是Andy Plata。 Julie:我是Julie Plata。很高兴今天能在这里为大家演讲。我和Andy共同拥有一些服务于全球印刷业的公司。我们也为全球许多印刷类刊物撰文,我想诸位应该已经读过我们在科印传媒《数码印刷》杂志上发表的文章。  相似文献   
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