modeling n. 制造模型的方法,造型(術(shù));塑像術(shù);【美術(shù)】立體感 ...
approximate vt. 1.使接近。 2.接近;走近。 3.近似,約計。 4.模擬。 5.估計。 approximate a solution to a problem 使問題近于解決。 approximate something to perfection 使某物臻于完善。 The total income this year approximates 10,000 dollors. 今年總收入接近一萬元。 approximate the motions of the stars in a planetarium 在天文館中模擬行星的運(yùn)行情況。 We approximated the distance at 100 miles. 我們估計行程距離為100英里。 vi. 近于。 His income this year approximates to 8,000 dollars. 他今年的收入接近八千美元。 adj. 近似的,大概的。 an approximate account 簡要的說明。 an approximate date 大約的日期。 the approximate estimate 大概的估計。 an approximate number 概數(shù)。 an approximate value 近似值。 adv. -ly 大體,大致。
Control systems in modern automatic engineering are nonlinear , time - changed and indefinite . lt is difficult to model by traditional method , even sometime impossible . under these circumstances we should apply model identification to gain the approximate model of object for effective control , there are many models to be chosen , fuzzy model is one of them , it is put forward with the development of fuzzy control . fuzzy model has characteristics of general approximation and strong nonlinear , it is fit for describing complex , nonlinear systems . to avoid rules expansion when the number of input values are very big . in this paper we apply hierarchical fuzzy model to resolve this problem , we also illustrate it has general approximation to any nonlinear systems . genetic algorithm is a algorithm to help find the best parameters of process . lt has abilities of global optimizing and implicit parallel , it can be generally used for all applications . in our paper we use fuzzy model as predictive model and apply ga to identify fuzzy model ( including hierarchical fuzzy model ) , we made experiments to nonlinear predictive systems and got very good results . the paper contains chapters as below : chapter 1 preface 現(xiàn)代控制工程中的系統(tǒng)多表現(xiàn)為非線性、時變和不確定性,采用傳統(tǒng)的建模方法比較困難,或者根本無法實現(xiàn),在這種情況下,要實現(xiàn)有效的控制,必須采用模型辨識的方法來獲取對象的近似模型,并加以控制,目前用于系統(tǒng)辨識的模型種類很多,模糊模型是其中的一種,它隨著模糊控制的發(fā)展而被人提出,模糊模型具有萬能逼近和強(qiáng)非線性的特點(diǎn),比較適合于描述復(fù)雜非線性系統(tǒng),為了解決模糊模型在輸入變量較多時規(guī)則數(shù)膨脹的問題,文中引入遞階型模糊模型,并引證這種結(jié)構(gòu)的通用逼近特性。遺傳算法是模擬自然界生物進(jìn)化“優(yōu)勝劣汰”原理的一種參數(shù)尋優(yōu)算法,它具有隱含并行性和全局最優(yōu)化的能力,并且對尋優(yōu)對象的要求比較低,在工程應(yīng)用和科學(xué)研究中,得到了廣泛的應(yīng)用,本文將遺傳算法引入模糊模型的辨識,取得了很好的效果。
The innovations of this thesis are as the follows : 1 ) it is analyzed that the lower - order jacobi - anger expansion model for an incoherently distributed source has better accuracy performance than some other approximate source models such as space frequency model , two - point source model , and low - rank approximate model . using the parametric decoupling property of the ja - based model , a novel angular parameter estimator is proposed , which is very robust in case of large angular spreading 本文從這三個方面開展了空間分布源波達(dá)方向估計研究,創(chuàng)新點(diǎn)包括: 1 )分析了低階jacobi - anger級數(shù)展開近似模型的誤差性能;利用該近似模型的參數(shù)解耦特性,提出了一種新的波達(dá)方向估計器,在大角度擴(kuò)展條件下,該估計器表現(xiàn)非常穩(wěn)健。