Global ETD Search

161	兩個組合數學的主題： Hadamard 矩陣的建構及有關森林的研究 / Two Combinatorial Topics: Constructions of Hadamard Matrices and Studies of Forests 施耀振, Shih,Yaio-Zhern Unknown Date (has links) 在這篇論文，我們主要探討兩個獨立的組合數學主題：一個是Hadamard矩陣的建構，一個是有關森林的研究。在第一個主題，所得者又分為二，其一，我們從一個已知的Hadamard矩陣，利用Sylvester的方法去建構名為Jm-Hadamard矩陣。從這個矩陣裡，藉由在Sm上適當的排列，可以獲致其他2mm!-1個Hadamard矩陣。另外，我們引進Jm-class的概念，將之寫成CJm，並探討當n整除n'時，CJn'是否包含於CJn。關於這個問題，我們得到最初的結論是CJ8 CJ4 CJ2。其二，在已知的t個階數分別是4m1，4m2，…，4mt的Hadamard矩陣，希望獲得一個階數是2km1m2… mt的Hadamard矩陣，使得k值愈小愈好。我們可以找到最小指數的上界，這個數稍好於Craigen及de Launey所得到的值。在第二個主題裡，我們致力於三個目標，首先，我們將平面樹上的一些結果，推廣到平面森林上，諸如Shapiro的結果，葉子的偶數、奇數問題，Catalan數與類似數之間的恒等式。其二，我們用了一個很簡潔的方法去證明Chung-Feller定理，也獲致相關的結果及應用。最後，我們以研究數種n-caterpillars的優美標法，作為本文的結束，最特別的是我們可藉用拉丁方陣去建構2n-caterpillars的優美標法。 Kronecker乘積 Sylvester-Hadamard矩陣 J_m-Hadamard矩陣正交對 Weighing矩陣最小指數平面森林 Catalan數 Motzkin數 Riordan數 Narayana數 Dyck路徑 Motzkin路徑 Chung-Feller定理優美標法拉丁方陣 J_m-classes n-Caterpillars
162	Crisis, endeudamiento y desposesión en el mundo rural catalán de finales del siglo XIX Garcia, Ricard, 1968- 16 April 2009 (has links) Esta tesis doctoral examina las repercusiones de la llamada "Gran Depresión" de finales del siglo XIX sobre la sociedad rural catalana a partir del análisis del que puede ser visto como uno de los síntomas más característicos de cualquier crisis agraria: la pérdida de derechos de propiedad sobre la tierra o sobre otros inmuebles de carácter rural como consecuencia de reclamaciones de deudas, promovidas por particulares o por el Estado, que culminaron en subasta pública.El trabajo ha sido dividido en dos secciones. En la primera se analiza la desposesión causada por procedimientos ejecutivos impulsados por la Administración de Hacienda por impuestos impagados. En la segunda se ha estudiado la actividad judicial que concluyó en subasta pública de bienes inmuebles, y se han mostrado sus relaciones con la situación agraria, especialmente en los sectores del trigo y de la vid. / This Doctoral Thesis examines the repercussions of the Great Depression of end of the 19th century on the Catalan rural society from the analysis of the one that can be seen as one of the most characteristic symptoms of any agrarian crisis: the loss of property rights on the land or on other real estate of rural nature as a consequence of claims of debts carried out by individuals or by the State that culminated in public auctions.The work has been divided in two sections. In the first, the dispossession because of administrative executive procedures by unpaid taxes that took place in Catalonia in this period is analysed. In the second, we have studied the judicial activity that finished in public auction of real estate goods and we tried to relate it to the agrarian situation, especially in the wheat and the wine sectors. Dispossession of real state goods Embargos de immuebles Embargament d'immobles Financial debt Endeutament fiscal Endeudamiento fiscal Mortgage credit Crèdit hipotecari Crédito hipotecario Catalan rural society Món rural català Mundo rural catalán Rural credit Crèdit rural Crédito rural Agrarian crisis Crisi agrària Crisis agraria Subasta pública Public auctions 332 9
163	Innovative masonry shell construction in India's evolving building crafts : a case for tile vaulting Jalia, Aftab January 2017 (has links) This thesis uses the lens of building technology to examine cultural exchange and its relationship to the building crafts. By focusing on masonry vaulting in India, my research brings together two worlds – one that shines light on the variety of innovative masonry shell construction techniques that exist in the county and another that seeks to evaluate the scope of tile vaulting, an over 600-year old Mediterranean building technique, within India’s evolving building crafts culture. This thesis is organized in three parts: PART ONE Tile Vaulting and Relevance Today \| A Brief History of Masonry Shells in India Part one introduces tile vaulting’s unique principles compared to other vaulting traditions while contextualizing its relevance to present day India. A survey of varied masonry vaulting techniques and modules, endemic and imported, practiced across India is presented against the backdrop of what is a predominantly reinforced concrete-based construction industry. PART TWO Modules, Methods and Motivations The second part of this research comprises case studies that include some of India’s most iconic buildings such as the Villa Sarabhai by Le Corbusier, the National Institute of Design by Gautam Sarabhai and Sangath by B.V. Doshi, each of which employed innovative construction techniques for its vaults. The production and use of the enigmatic ceramic fuses in India is examined for the first time alongside their indigenous cousins: burnt clay tubes. Together with Muzaffarnagar vaulting, the case studies reveal cultural motivations for architectural expression and production in postcolonial India. PART THREE Prototypes \| Comparatives \| Limitations & Extension of Research Part three presents five tile vaulting prototypes in India constructed with local artisans to gain understanding of its cultural reception, assess effective transfer of skills and potential internalisation. Recommendations for tile vaulting’s potential uptake into mainstream architectural production is evaluated by comparing findings against prevalent building methods and by contextualizing current architectural trends and social policy. Limitations and scope for extension of research are also discussed.
164	Shift gray codes Williams, Aaron Michael 11 December 2009 (has links) Combinatorial objects can be represented by strings, such as 21534 for the permutation (1 2) (3 5 4), or 110100 for the binary tree corresponding to the balanced parentheses (()()). Given a string s = s1 s2 sn, the right-shift operation shift(s, i, j) replaces the substring si si+1..sj by si+1..sj si. In other words, si is right-shifted into position j by applying the permutation (j j−1 .. i) to the indices of s. Right-shifts include prefix-shifts (i = 1) and adjacent-transpositions (j = i+1). A fixed-content language is a set of strings that contain the same multiset of symbols. Given a fixed-content language, a shift Gray code is a list of its strings where consecutive strings differ by a shift. This thesis asks if shift Gray codes exist for a variety of combinatorial objects. This abstract question leads to a number of practical answers. The first prefix-shift Gray code for multiset permutations is discovered, and it provides the first algorithm for generating multiset permutations in O(1)-time while using O(1) additional variables. Applications of these results include more efficient exhaustive solutions to stacker-crane problems, which are natural NP-complete traveling salesman variants. This thesis also produces the fastest algorithm for generating balanced parentheses in an array, and the first minimal-change order for fixed-content necklaces and Lyndon words. These results are consequences of the following theorem: Every bubble language has a right-shift Gray code. Bubble languages are fixed-content languages that are closed under certain adjacent-transpositions. These languages generalize classic combinatorial objects: k-ary trees, ordered trees with fixed branching sequences, unit interval graphs, restricted Schr oder and Motzkin paths, linear-extensions of B-posets, and their unions, intersections, and quotients. Each Gray code is circular and is obtained from a new variation of lexicographic order known as cool-lex order. Gray codes using only shift(s, 1, n) and shift(s, 1, n−1) are also found for multiset permutations. A universal cycle that omits the last (redundant) symbol from each permutation is obtained by recording the first symbol of each permutation in this Gray code. As a special case, these shorthand universal cycles provide a new fixed-density analogue to de Bruijn cycles, and the first universal cycle for the "middle levels" (binary strings of length 2k + 1 with sum k or k + 1). shorthand universal cycles combinatorial generation minimal-change order loopless algorithm efficient algorithm combinations multiset permutations balanced parentheses Dyck words Catalan paths Schroder paths Motzkin words linear-extensions posets connected unit interval graphs inversions binary trees k-ary trees Lyndon words pre-necklaces theoretical computer science discrete mathematics combinatorics brute forcs de Bruijn cycles bubble languages cool-lex order lexicographic order combinatorial enumeration stacker-crane problem traveling salesman problem middle levels fixed-density de Bruijn cycle fixed-content

Page generated in 0.1121 seconds