Parametric representation of the normalized property curve is studied . 8 同時,還提出了歸一化特性曲線的參數(shù)化描述方法。
Basically , they can be classified into three categories : mesh representation , parametric representation and implicit representation 這些方法大體上可以分為三類:網(wǎng)格表示、參數(shù)表示以及隱式代數(shù)表示。
For a simple and fast visualization of curves and surfaces , the model widely used is the mesh representation . parametric representation is suitable to a cad use 網(wǎng)格表示適用于快速顯示曲線曲面,參數(shù)表示適用于cad使用,隱式代數(shù)表示在曲面求交、圖形裁剪中應(yīng)用廣泛。
American journal of botany , 2003 , 90 : 333 - 338 . 19 fougerolle y d , gribok a , foufou s , truchetet f , abidi m a . boolean operations with implicit and parametric representation of primitives using r - functions 在此,超形的表面以所允許的精度進行采樣生成,而它們的頂點和面片將根據(jù)隱函數(shù)的刻畫來決定它們是否用于最終實體表面的生成。
Abstract : the idea of feature library in two - dimension is proposed which absorbs the thoughts and methods about step . adopting the information modeling language express , the parametric representation schema of the feature based on the classifacation is introduced , too 文摘:借鑒step提供的思想與方法學(xué),提出了二維視圖特征類庫的思想,在二維特征分類基礎(chǔ)上,采用express信息建模語言進行二維特征的參數(shù)化描述。
In section 4 . 2 we analyze its main idea and algorithm in detail , two relevant theorems included ; section 4 . 3 provides plenty instances so to explain its nonlinear dimension reduction ability , section 4 . 4 propose a combined method that integrates the advantage of various methods . in section 4 . 5 we analyze some significant problems in lle , including the locality of manifold representation , the choice of the neighborhood , the intrinsic dimension estimation and the parametric representation of mapping . in section 4 . 6 we design an algorithm for estimating the intrinsic dimension in the base of locally linear approximation and discuss the choice of its parameters 第四章是本文的重點內(nèi)容,研究一種全新的非線性降維方法? ?局部線性嵌入方法,對它的思想和算法進行了詳細(xì)的分析,給出算法兩個相關(guān)定理的證明;第三節(jié)對比主成分分析,通過實例說明局部線性嵌入方法的非線性降維特征;第四節(jié)在此基礎(chǔ)上提出了旨在結(jié)合兩者優(yōu)勢的組合降維方法;第五節(jié)提出了局部線性嵌入方法中存在的若干關(guān)鍵性問題,包括流形的局部性、鄰點的選擇、本征維數(shù)的估計和降維映射的表示,第六節(jié)基于局部線性近似的思想提出了一種本征維數(shù)的估計方法,設(shè)計了實用算法,結(jié)合實例對算法中參數(shù)的選取進行了討論;最后一節(jié)提出了一種基于局部線性重構(gòu)的圖形分類和識別方法,將其應(yīng)用于手寫體數(shù)字的圖像分類識別實驗,實驗得到的分類準(zhǔn)確率達(dá)96 . 67 。