首近似值 的英文怎麼說
中文拼音 [shǒujìnsìzhí]
首近似值
英文
first approximation-
( 4 ) on the efficient method for the dynamical core of the new generation multi - scale forecasting model i ) we present a new multi - level sparse approximate inverse preconditnioner for the complicated 3 - d helmholtz equations in the new generation weather forecasting model. as a result, the new sparse approximate inverse preconditioned gcr and gmres algorithms are given and successfully applied in the dynamical core. numerical tests show that the new algorithms perform very efficiently, and can greatly improve the efficiency of numerical model
對此，本文提出了一種基於逐層門限技術的近似逆矩陣稀疏模式預選方法，並構造了相應的稀疏近似逆預條件子，結合gcr演算法和g州[ r衛s演算法，首次將逐層門限稀疏近似逆預條件子應用於新一代多尺度預報模式動力內核的實際計算，數值實驗表明這里給出的方法可以大大提高數值模式的計算效率。The equation including the nonlinear dispersion, i. e. the modified nonlinear schrodinger ( mnls ) equation, is a better model. in this thesis, we take mnls solitons as a model for femtosecond soltions. then based on the recently developed direct perturbation theory for perturbed mnls equation, we study the raman self - frequency shift of femtosecond solitons and its suppression by the means of frequency filters. for this purpose, first, we define the physical parameters of mnls solitons ; next, through the direct perturbation theory for perturbed mnls equation, under adiabatic approximation, we obtain the evolving parameters of mnls soliton on our questions and then choose the parameters of frequency filters based on it ; at last, we directly numerically simulated our questions by split - step fourier ( ssf ) method after improving the arithmetic of the differentiation of the nonlinear item for satisfying mnls equation
本論文以mnls孤子作為光纖飛秒孤子的模型，通過新近建立的mnls孤子直接微擾理論，研究光纖中由拉曼效應引起的飛秒孤子在傳輸中的自頻移，以及通過頻率濾波對自頻移的抑制。為此，首先給出描述mnls孤子的各物理量，然後用mnls孤子直接微擾理論，解析地得到這些問題絕熱近似下的孤子參數演化，並由此選擇頻率濾波的參數，最後用分步傅里葉方法，在對非線性項微商的演算法做出了適合於mnls孤子的改善後，對拉曼效應及頻率濾波進行了直接數值模擬，其中頻率濾波參數用微擾理論確定。In the section 2, firstly based on the diffusion approximation theory, the temporal characteristics of the reflectance and the transmittance were theoretically analyzed in turbid tissues ; secondly, the curves were simulated that the intensity and the pulse shape of the time resolved reflectance and transmittance versus the absorption a, the scattering s and the anisotropy coefficient g in two different boundary conditions : semi - infinite turbid media and homogeneous slab ; at last, the optical properties can be derived from the curves ; in the section 3, the conditions of ultra short laser pulses of different pulse - width and shapes has been theoretical analyzed and calculated, besides, the simulated the curves of the intensity and pulse shapes of the reflectance and transmittance in a homogeneous slab are obtained for use and future studying
第二章中首先根據漫射近似理論對超短脈沖在以生物組織為典型的混濁介質中傳輸進行了理論分析，然後對兩種邊界條件下產生的漫反射、漫透射光脈沖強度和形狀隨各光學特性參數的變化情況進行了數值模擬，最後得到了混濁介質的光學特性參數與漫反射、透射脈沖強度與形狀的關系曲線。第三章對不同形狀和脈寬的脈沖光源入射到混濁介質中產生的漫反射、漫透射脈沖的強度和形狀進行了理論分析和數值模擬，並將高斯脈沖與方波脈沖情況進行了對比，得到了各種情況的漫反射、漫透射脈沖強度、形狀與各光學特性參數的關系曲線，這對從分析脈沖形狀中提取介質的光學特性參數的信息有重要的意義。The error analysis model of sampling system was set up for the first time, by combining the saddlepoint approximation analysis and numerical arithmetic, which greatly increased the potential of further application and improved the reliability of the error approximation of the optical sampling histogram
論文首次建立了採用鞍點近似法與數值演算法相結合的取樣系統誤差分析模型，大大擴展了鞍點近似演算法的適用范圍，提高了誤碼率估算的可靠性。論文提出了基於時分取樣方法的光子模數轉換。The search space is divided into many small areas, and each area is given a certain pheromone value. according to the state transition rules, the artificial ants move to the next solution which is generated randomly or calculated by particle swarm optimization. local search strategy is also added into psaco so that the search speed and precision is enhanced
該演算法首先將連續對象定義域平均分成許多邊緣相互重疊的小區域，區域的稠密程度決定了演算法解的精度，每個區域賦予一定的信息素值;螞蟻根據狀態轉移規則在隨機生成的可行解與利用微粒群演算法得出的可行解之間選擇下一步要去的位置;引入局部尋優策略，加強近似最優解鄰域內的局部搜索，提高搜索速度和精度。Using the theories of probability, algebra and number theory comprehensively, we investigate a class of boolean functions with three - valued walsh spectrum in the first part of this dissertation : the properties of the extended semi - bent functions, which are constructed from any two bent functions, are studied, followed by the structure characteristics of the boolean functions satisfying propagation criterion with respect to all but two vectors ; the definition and cryptographic properties of k - order quasi - bent functions are proposed whose walsh spectrum takes on only three values. some sufficient and necessary conditions are offered to decide whether a boolean function is a k - order quasi - bent function ; a special method is presented to construct the k - order quasi - bent functions, whose cryptographic properties are explored by the matrix method, which is different from the method of walsh spectrum and that of autocorrelation of boolean functions ; the application of this kind of boolean functions in the fields of stream cipher, communications and block ciphers is discussed, which shows the great importance of the fc - order quasi - bent functions ; some methodology are proposed to construct the k - order quasi - bent functions, including the complete construction by using the characteristic matrices of boolean functions, and the recursive method by two known k - order quasi - bent functions we further extend our investigation to the ring zp, where p is a prime, and the similar results are presented as far as the p - valued quasi - generalized - bent functions are considered
本文首先綜合運用概率論、代數學、數論等基礎學科的理論知識，並以頻譜理論作為主要研究工具，對一類譜值分佈相對均勻的函數? ?廣半bent函數、 k階擬bent函數和p值k階擬廣義bent函數進行了系統、深入的研究，給出了廣半bent函數定義，並探討了廣半bent函數的密碼學性質；給出了k階擬bent函數和p值k階擬廣義bent函數的定義及等價判別條件；討論了k階擬bent函數和p值k階擬廣義bent函數與部分bent函數和p值廣義部分bent函數的關系，探討了它們的密碼學性質；給出了k階擬bent函數和p值k階擬廣義bent函數的典型構造方法，並將對k階擬bent函數的密碼性質的研究轉化到對一類特殊的矩陣的研究上；利用布爾函數的特徵矩陣原則上給出了k階擬bent函數的一種完全構造方法，還給出了從已有的p值k階擬廣義bent函數出發，遞歸構造變元個數更多的p值k階擬廣義bent函數的方法；初步探討了k階擬bent函數在序列密碼、分組密碼以及通信中的應用；給出了一類布爾函數walsh譜的分解式，並利用這類布爾函數的walsh譜分解式給出了一類近似穩定的布爾函數的構造，特殊情形下為k階擬bent函數；利用代數數論的知識考察了p值k階擬廣義bent函數的譜特徵，並給出了k階擬廣義bent函數與所有仿射函數的符合率特徵等等。First, we concisely recall the formation and development of bose - einstein condensa - tion ' s theory and it ' s experimentation. secondly, we briefly intro - duce some properties of weakly interactive bose gases, and derive the nonlinear gross - pitaevskii equation that is the condensate macroscopic wave function ' s equation. thirdly, we give a exam - pie, an approximation analytical solution of the gross - pitaevskii equation in a spherical symmetric harmonic trap is derived by a perturbation theory approach, this solution is consistent with that numerically obtained
全文共分為四章：第一章首先簡要的介紹和回顧了玻色-愛因斯坦凝聚理論的產生和發展，以及其實驗研究的過程，然後著重介紹了弱相互作用的玻色氣體的一些性質，並推導出了凝聚體宏觀波函數滿足非線性的gp方程，還以球對稱的諧振子勢為例，用標準的微擾方法求出了定態的gp方程近似解，發現其與已知的數值結果符合得很好。Lastly, aiming at the poor results which all current algorithms do for directional textures, and cannot synthesis texture directly, aiming at the particularity of this kind of textures, we bring forward the conceptions of non frontal parallel textures and frontal parallel textures. by analyzing texture ' s direction through fourier spectrum, we introduce the conception of main direction, and solve the approximation value of texture ' s main direction by discrete approximated approach. by this way, we can synthesis indirectly simple structural non frontal parallel textures
最後針對現有演算法對帶有方向的紋理合成效果差，無法直接合成紋理圖像的難點，本論文首先提出了非正平行紋理與正平行紋理的概念，分析了它們之間的內在聯系，引入了兩個角度參數來描述紋理的朝向，採用傅立葉頻譜法分析紋理的方向特性，並提出了紋理主方向的概念，本論文引入離散逼近的方法來求解出紋理主方向的近似值，這樣我們就能用一種間接的方法合成簡單的結構性非正平行紋理。First, the formula for average intensity of ocean reverberation is deduced on the basis of ray theon " for monostatic case, then it is proved by computer simulation and experiment data
本文首先從分層介質的射線理論出發導出傾斜海底收發合置淺海近程海洋混響平均強度的近似表達式，並對其進行數值分析與實驗驗證。The prevailing approaches depend on costly time domain convolution, using the frequency domain network parameters such as s - parameter, y - parameter or abcd parameters to find analytic solution, and finding the time domain approximations by fft or even numerical inversion of laplace transform ( nitl ) if there are a large number of nonlinear devices in the network
目前盛行的方法是採用費時的時域卷積法：首先運用諸如s 、 y 、 abcd的頻域網路參數求出頻域解析解，然後通過快速福利葉變換（ fft ）得出時域近似解，如果網路中存在大規模的非線性設備，還需要採用數值逆拉普拉斯變換（ nilt ） 。The acceleration is first evaluated from governing equation, secondly, the formulae of displacement and velocity are developed basing on some assumptions, and then the discrete expressions of the response mean square value are deduced
首先，直接從控制方程出發計算加速度，其次，給出了位移和速度的一種近似計算公式，最後，推導出響應均方值的離散計算表達式。Chapter 5 directly sets out from the green formulae of velocity potential due to the existence of lifting force, adopts an approximate kutta condition and firstly calculates the maneuvering hydrodynamics of a wigley ship with an attack angle using the present method of b spline
由於有升力的存在，第5章直接從速度勢格林公式出發，並採用了一種近似的kutta條件，首次採用b樣條邊界元方法對作斜航船武漢理} _人學博十學位論文體的操縱水動力開展了數值計豹( 3 ) by means of expanding the aperture function into a finite sum of complex gaussian functions, the propagation of fgbs through a paraxial optical abcd system with hard - edged aperture is studied, and the approximate closed - form equations of apertured fgbs are obtained for the first time. the results obtained by using the approximate closed - form equation and collins formula are compared, and the condition under which the approximate closed - form equation is applicable is analyzed
（ 3 ）利用光闌函數的復高斯函數展開法對截斷平頂高斯光束的傳輸作了研究，首次得到了截斷平頂高斯光束在近軸abcd光學系統中傳輸時的近似解析傳輸公式，通過比較用近似傳物公式和colhns公式直接數值積分所得的結果，得出了近似公式的適用范圍。分享友人