【導讀】LMS算法是時域變換，DCT是頻域變換，文章采?；镜母拍?，是其它許多算法的基礎，是實際中使用的最廣泛的一種算法。表1詳細地給出LMS算法，其中x為n時刻濾波器的輸入信號，w為。為濾波器的估計誤差，u為更新步長。為特征值中的最大值。這必然導致其它收斂模式的收斂速度下降，針對LMS算法存在特征值分散度的問題，我們可以采用牛頓法來進行克服，從根本上消除了最陡梯度下降法受特征值分布影響的缺陷。牛頓方法其實就是。TDAF就是變換域中的LMS算法，所以也稱為TDLMS算法。常被信號處理和圖像處理使用，用于對信號和圖像進行有損數(shù)據(jù)壓縮。葉變換緊密相關的數(shù)學運算。在傅立葉級數(shù)展開式中，如果被展開的函數(shù)是實偶。稱之為離散余弦變換。該變換有八種表達形式，其中主要的四種變換形式如下圖。本文采用其中第二種來進行討論。據(jù)壓縮信號重建的時域波形存在失真，但在工程上這樣的失真是允許的。失真度指標下，通過DCT變換可以使數(shù)據(jù)得到很大程度的壓縮。

　　

【正文】 developed empire.‖(Liu Xiaohan, 2020: 22) It is worth mentioning, she realizes the side of hero from Sherlock Holmes in this study. ―… Holmes represents the scientific and rational. He tries his best to dislodge all the colonialism poisons which are invading his mind and recovers the original British cultures and orders.‖(Liu Xiaohan, 2020: 22) Wang Ting‘s Complete Sherlock Holmes: the Panorama Gram of Victorian Era studies various aspects in Victorian Era with the descriptions in Conan Doyle‘s tales of Sherlock Holmes. ―The popularity of Complete Sherlock Holmes is not only for its attractive stories, but also for its making readers understand a real London, a real Victorian Era.‖(Wang Ting, 2020: 104) Wang Ting analyzes the economy, science, culture, social classes and the minds of the public. What is more, Wang Ting realizes the change of women‘s power in this work. ―The women widely expend their views and realize the importance to strive the rights for themselves. The Feminist Consciousness is awakening.‖(Wang Ting, 2020: 106) The points in the thesis are useful in this study, providing the detailed date of Victorian Era. Feng Xinhua holds that the word ―gentleman‖ originates in Victorian Era. Yu Xiaoqun points the Sherlock Holmes‘ influences to the society in Victorian Era in his Discussion on the Social Condition of Holmes39。s Image and His Character Charm which is published in Writer Magazine. It presents the Sherlock Holmes changes the London of Victorian Era. ―For a long time, Holmes, the amazing character who was created by the famous British writer Arthur Conan Doyle, is not the character in the novels again, and he bees a man who has a great influence to British people.‖ (Yu Xiaoqun, 2020: 67) And her study analyses the image of Sherlock Holmes. The most impressive part is she thought Holmes is a ―lone hero‖ in London. ―In a sense, although Holmes lives in the city, he is just as Robinson in the lonely island. His fighting will shows the spirit and value of individual struggle. His creativity and intelligence embodies the charm from human.‖ (Yu Xiaoqun, 2020: 68) Previous Studies on the Tales of Sherlock Holmes The tales of Sherlock Holmes is thought as the Bible in detective novels. As same as ―the study of Shakespeare‖, there is ―the study of Holmes‖, too. And the foreign and domestic scholars make great contributions to the study. 寧波大學科學技術學院本科畢業(yè)設計（論文） 11 The foreign scholars presented their achievements in their monographs. Christopher Morley and Steven Rothman wrote The Standard Doyle Company: Christopher Morley on Sherlock Holmes together, and published in 1990. That Monograph collected large numbers of famous writers‘ mentaries. In those mentaries, the famous British novelist William Somerset Maugham‘s mentary was wildly known, ―No detective stories have ever had the popularity of Conan Doyle‘s and because of the invention of Sherlock Holmes I think it must be admitted that none have so well deserved it.‖ (Christopher Morley and Steven Rothman, 1990: 209) The mentaries in that book will make this thesis bee in persuasiveness. Jeffrey Meyers and Valerie Meyers created their work—The Sir Arthur Conan Doyle Reader: from Sherlock Holmes to Spiritualism. This work pointed out the social hero side in Sherlock Holmes‘s character. The readers can find this point in most pages of that book, and it shows the two writers‘ respect to this hero. ―Conan Doyle was an instinctive storyteller, with a Dickensian eye for the striking and often macabre detail. He shared Dickens‘s sense of justice and social responsibility, his warm humanity and delight in the lively individuality of the characters he created.‖ (Jeffrey Meyers and Valerie Meyers, 2020: 10) That work successfully makes readers see Holmes‘s working hard for the London of Victorian Era and connect our detective with hero. Andrew Smith collected much information from the previous studies, and found the respect to women from the tales of Sherlock Holmes. And his achievement was published by Manchester University Press in 2020. He provided his mind in his Victorian Demons: Medicine, Masculinity, and the Gothic at the findesi232。cle, ―The gradual emergence of a selfconscious scrutiny of gender is charted in these texts and it constitutes a tradition of scrutiny which is developed by Doyle in the Sherlock Holmes stories.‖ (Andrew Smith, 2020: 127) In Sherlock Holmes39。 London, which was published in Crazy English Reader, the writer Joshua Hammer told the stories during Sir Arthur Conan Doyle writing the tales of Sherlock Holmes. It provides many valuable historical data. The domestic scholars studied a lot in this field. In 2020, Zhang Jiong‘s study, Discussion on Holmes’s Image, was published in the Journal of Guyuan Teachers College. In this study, he tried to inquire into the image of Holmes by the details in the tales of Sherlock Holmes. ―His unbelievable fancy, the changeful camouflage and the power of knowing the essence in things are the perfect bine between science and art.‖ (Zhang Jiong, 2020: 75) Chen Xiaolan, the associate professor in Comparative Literature in school of Literature, Shanghai University, she 寧波大學科學技術學院本科畢業(yè)設計（論文） 12 talked about the relation between the novel and the city in her Detective Novels and the control of Cities: A Study Based on Conan Doyle’s Novels. What is more, she held the opinion that Holmes tried his best to help the London, even the world. ―… the rent apartment (Baker Street 221B) is full of the warm of family. It is not only Holmes and Watson‘s harbor of refuge, but also the information counter to the people in London, even in everywhere in Europe.‖(Chen Xiaolan, 2020: 355) According to the paragraph above, we can find that Mrs. Chen shows the positive view towards the opinion that Sherlock Holmes is a hero in the London of Victorian Era. At the same