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121.
This paper presents an efficient optimal control and recursive dynamics-based computer animation system for simulating and controlling themotion of articulated figures. A quasi-Newton nonlinear programmingtechnique (super-linear convergence) is implemented to solve minimumtorque-based human motion-planning problems. The explicit analyticalgradients needed in the dynamics are derived using a matrix exponentialformulation and Lie algebra. Cubic spline functions are used to make thesearch space for an optimal solution finite. Based on our formulations,our method is well conditioned and robust, in addition to beingcomputationally efficient. To better illustrate the efficiency of ourmethod, we present results of natural looking and physically correcthuman motions for a variety of human motion tasks involving open andclosed loop kinematic chains. 相似文献
122.
随着无线Internet用户的急剧增长和数据业务的快速增加,对下代无线网络系统提出了越来越高的要求。各运营商更是积极地部署各种宽带无线接入(BWA)技术;第三代无线移动通信技术(3G)就是其中的备选方案之一。同时,随着无限局域网(WLAN)802.11的成功商用,IEEE802.16以及对应的无线城域网(WMAN)空口也成为宽带无线接入技术的有利可选方案。在本文中,我们将对这两种技术提供详细的性能分析和比较。 相似文献
123.
In this paper, we investigate the problem of robust H/sub /spl infin// performance and stabilization for a class of uncertain fuzzy systems with Frobenius norm-bounded parameter uncertainties in all system matrices. Both continuous- and discrete-time uncertain fuzzy systems are considered under a unified treatment called bounded real lemma for fuzzy systems. Unlike the bounded real lemma in the linear theory of robust H/sub /spl infin// control where necessary and sufficient conditions were obtained, only sufficient condition based on Lyapunov method is shown. Furthermore, connection between robust H/sub /spl infin// problems involving uncertainty and standard uncertainty-free H/sub /spl infin// problems is established via matrix algebra. As for controller synthesis, a state feedback fuzzy control law is designed via relaxed linear matrix inequality (LMI) formulations. 相似文献
124.
Angrisani L. Baccigalupi A. Schiano Lo Moriello R. 《IEEE transactions on instrumentation and measurement》2006,55(4):1077-1084
This paper deals with distance or level measurements based on ultrasonic time-of-fight estimation. Moving from a past experience concerning the proposal of a method based on discrete extended Kalman filter (DEKF) to overcome some limitations of already available ultrasonic-based techniques, a new digital signal processing method capable of granting further improvements is presented. The method is based on the unscented Kalman filter (UKF), which is a new extension of the Kalman filter theory mandated to face some DEKF problems, mainly due to its inherent linearization approach. To this aim, UKF is applied to the acquired ultrasonic signal in order to estimate the returned echo envelope as well as to locate its onset more accurately. After describing key features and implementation issues of the new method, the results obtained in a number of tests on simulated and actual ultrasonic signals, which assess its reliability and effectiveness as well as advantages with respect to the previous one, are given. 相似文献
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Jie B.B. Li M.F. Lou C.L. Chim W.K. Chan D.S.H. Lo K.F. 《Electron Device Letters, IEEE》1997,18(12):583-585
Interface traps in submicron buried-channel LDD pMOSTs, generated under different stress conditions, are investigated by the direct-current current-voltage (DCIV) technique. Two peaks C and D in the DCIV spectrum are found corresponding to interface traps generated in the channel region and in the LDD region respectively. The new DCIV results clarify certain issues of the underlying mechanisms involved on hot-carrier degradation in LDD pMOSTs. Under channel hot-carrier stress conditions, the hot electron injection and electron trapping in the oxide occurs for all stressing gate voltage. However, the electron injection induced interface trap spatial location changes from the LDD region to the channel region when the stressing gate voltage changes from low to high 相似文献
127.
Failure to comply with medical regimes is endemic and is extremely costly both in economic and wellness terms. Adherence failure is explored in this study of 95 non-insulin-dependent-diabetics (NIDDM) subjects. Results indicate that the factors governing failure to adhere are not necessarily the obverse of psychosocial factors correlated with successful adherence to medical regimes. Success in complying to wellness behaviours was a function of positive attitudes and an acceptance of the challenges of the illness, the capacity to utilise family support, and not having negative self esteem. Failure to comply was a function of a syndrome of stress, chronic and transient mental distress. Common to both success and failure in complying were attitudes to health professionals, extent of knowledge about the disease and perceptions of the success or otherwise in overcoming inconvenience and barriers which might impede compliance. 相似文献
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氧气平炉的电除尘灰粒径小,水渗透性差,因而极易在空中飘浮,在装卸、运输、储存的过程中,易造成二次环境污染。用颗粒状没有粘性的平炉水淬渣作吸附体,与电除尘灰一起加水搅拌成渣灰混合料,既解决了电除尘灰对环境的污染问题,又为烧结厂提供了合格原料。 相似文献