共查询到19条相似文献,搜索用时 115 毫秒
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研究了基于哼唱的歌曲检索算法,提出了一个完整的哼唱检索框架,由特征提取模块、歌曲模板库模块、旋律匹配模块组成。为改善系统性能,在旋律提取部分采用基于小波变换的基音提取方式。旋律匹配模块在对传统的动态时间弯折进行分析后,对之进行了改进。在548首歌曲的测试集上,该系统的识别效果达到89.1%。 相似文献
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一种计算MDCT的快速算法 总被引:2,自引:0,他引:2
提出了一种计算MDCT的快速算法,并分析了算法的计算复杂度。与利用FFT计算的算法相比,本算法的计算复杂度降低了约一半。最后给出该算法的计算机仿真结果。 相似文献
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一种DWT与DCT结合的盲音频水印算法 总被引:22,自引:0,他引:22
该文提出了一种新的盲音频水印算法。它充分利用离散小波变换的多分辨率特性和离散余弦变换的能量压缩能力,通过量化处理把降维后的二值图像水印嵌入到原始的音频信号中,在水印的提取过程中不需要原始音频信号的参与。仿真实验证明了算法的鲁棒性和不可感知性。 相似文献
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二维离散余弦变换的一种新的快速算法 总被引:2,自引:0,他引:2
本文介绍了二维离散余弦变换(DCT)的一种新的快速算法,对于N×N DCT(N=2^m),只需用N个一维DCT和若干加法运算。与常规的行-列法相比,所需的乘法运算量减少了一半,也比其它的快速算法的乘法运算量要少,而加法运算量基本上是相同的。 相似文献
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传统的无线通信中,由于外部环境的干扰,信道的不稳定,网络的中断率比较高。在信道条件较差时,通信性能较差。本文利用无线通信节点间的合作,通过不同节点对信息的中继放大、解码(或者网络编码),对直接传输的无线信道性能进行改进,大大提高了网络性能,降低网络的中断率;通过比较不同频谱效率下的不同转发方式的中断率性能,选择合适的传输方法。仿真实验得到:频谱效率小于一定值的情况下,利用放大和网络编码转发方式的性能大大高于直接传输方式。 相似文献
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Wen-Jang Jiang Lung-Chien Chen Meng-Chyi Wu Hsin-Chieh Yu Hung-Pin Yang Chia-Pin Sung Jim-Yong Chi Chun-Yuan Huang Yi-Tsuo Wu 《Solid-state electronics》2002,46(12):2287-2289
In this article, we propose a new process method to improve the light output power of GaAs vertical-cavity surface-emitting lasers (VCSELs). The VCSELs with filling Al metal into the ring trench will exhibit a higher quantum efficiency and have a light output power of 1.45 times higher than those without filling Al. In addition, the trench filled with Al metal can benefit in the bonding process and behavior as a mirror to reduce the output power loss. These VCSELs show good output characteristics and high-temperature operation. 相似文献
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随着无线网络的迅速发展,如何改进TCP在无线网络中的传输性能这一课题,已经成为国内外研究的热点.文章分析了现有的几种典型的TCP改进方案,并在此基础上介绍一种新的跨层方案.通过在传输层和链路层之间引入ARQ Snoop代理,在链路层检测并重传ARQ分组的同时,协调WLAN MAC子层的ARQ机制与TCP的ARQ策略. 相似文献
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Abnormal harmonics of significant magnitude are generated at the output and input terminals of a PWM (pulse-width-modulated) AC-to-DC power converter under unbalanced operating conditions. A new control strategy is presented to selectively cancel the generated lower-order abnormal harmonics at the output and input terminals and thereby to preserve the high-performance features of a PWM AC-to-DC power converter. The proposed technique essentially involves computing the sequence components of the unbalanced input supply and suitably counter-unbalances the PWM gating signals of the power converter switches to cancel the generated abnormal harmonics. The technique is essentially a feedforward approach and is suitable for higher-power GTO (gate turn-off thyristor) type PWM AC-to-DC power converters. A procedure for implementing this technique in real time is discussed. Selected results are verified experimentally on a prototype PWM AC-to-DC power converter 相似文献
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A new bonding-tool solution to improve stitch bondability 总被引:1,自引:0,他引:1
K.S. Goh 《Microelectronic Engineering》2007,84(1):173-179
A new bonding-tool solution is proposed to improve stitch bondability by creating a new surface morphology on the tip surface of a wire-bonding tool (capillary). The surface has relatively deep lines with no fixed directions. This new capillary has less slipping between the wire and the capillary tip surface and provides better coupling effect between them. Experiments of wire bonding on unstable lead frames/substrates, alloyed wire (2N gold wire) bonding, and copper wire bonding were carried out to confirm the effect of the new capillary on the stitch bondability. The experimental results are promising and have proved that the use of the new capillary could improve the bondability of the stitch bond and minimize the occurrence of short tail defects and non-sticking on lead during bonding. 相似文献
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Control engineers have been investigating and developing different on-line adaptation schemes to fine-tune performance of controllers after off-line design. Artificial neural network technology has shown satisfactory results for many control applications. However, certain types of nonlinear problems are difficult for the neural controller to learn by conventional on-line adaptation schemes, while the nonlinear system can be effectively controlled by incorporating heuristics knowledge. This paper presents an effective approach to incorporate heuristics control knowledge into a neural controller by off-line pre-training, then fine-tune the neural controller performance further by on-line adaptation. Experimental results on a servomotor system with significant nonlinear friction characteristics are used to demonstrate the effectiveness of the design approach. 相似文献