scholarly journals Improvements on Spectral Bisection

2021 ◽  
Vol 36 (36) ◽  
pp. 857-877
Author(s):  
Israel De Souza Rocha

In this paper, the third eigenvalue of the Laplacian matrix is used to provide a lower bound on the minimum cutsize. This result has algorithmic implications that are exploited in this paper. Besides, combinatorial properties of certain configurations of a graph partition which are related to the minimality of a cut are investigated. It is shown that such configurations are related to the third eigenvector of the Laplacian matrix. It is well known that the second eigenvector encodes structural information, and that can be used to approximate a minimum bisection. In this paper, it is shown that the third eigenvector carries structural information as well. Then a new spectral bisection algorithm using both eigenvectors is provided. The new algorithm is guaranteed to return a cut that is smaller or equal to the one returned by the classic spectral bisection. Also, a spectral algorithm that can refine a given partition and produce a smaller cut is provided.

2004 ◽  
Vol 34 (136) ◽  
pp. 455-468
Author(s):  
Hartwig Berger

The article discusses the future of mobility in the light of energy resources. Fossil fuel will not be available for a long time - not to mention its growing environmental and political conflicts. In analysing the potential of biofuel it is argued that the high demands of modern mobility can hardly be fulfilled in the future. Furthermore, the change into using biofuel will probably lead to increasing conflicts between the fuel market and the food market, as well as to conflicts with regional agricultural networks in the third world. Petrol imperialism might be replaced by bio imperialism. Therefore, mobility on a solar base pursues a double strategy of raising efficiency on the one hand and strongly reducing mobility itself on the other.


2011 ◽  
Vol 13 (2) ◽  
pp. 201-171
Author(s):  
Nāṣir Al-Dīn Abū Khaḍīr

The ʿUthmānic way of writing (al-rasm al-ʿUthmānī) is a science that specialises in the writing of Qur'anic words in accordance with a specific ‘pattern’. It follows the writing style of the Companions at the time of the third caliph, ʿUthmān b. ʿAffān, and was attributed to ʿUthmān on the basis that he was the one who ordered the collection and copying of the Qur'an into the actual muṣḥaf. This article aims to expound on the two fundamental functions of al-rasm al-ʿUthmānī: that of paying regard to the ‘correct’ pronunciation of the words in the muṣḥaf, and the pursuit of the preclusion of ambiguity which may arise in the mind of the reader and his auditor. There is a further practical aim for this study: to show the connection between modern orthography and the ʿUthmānic rasm in order that we, nowadays, are thereby able to overcome the problems faced by calligraphers and writers of the past in their different ages and cultures.


2013 ◽  
pp. 32-47
Author(s):  
S. V. Osipov

Geobotanical mapping of the territory in riverheads Bureya of 4500 sq.km is carried out and the map of a actual vegetation cover of scale 1 : 200 000 is prepared. The legend of the map is presented in the form of the text with three-level hierarchy of classes. At the heart of structure of a legend of the map such regularities of a vegetation cover, as its latitudinal zonality / altitudinal belts, situation in a relief and dynamic series lie. The largest divisions of the legend reflect, first, change of large classes of mesocombinations of vegetation at the level of belts and, secondly, distinction in a boreal - forestry belt between a vegetation cover of tops and slopes of mountains, on the one hand, and the bottoms of river valleys, with another. Divisions of the legend of the second level reflect, first, vegetation changes in the form of high-rise and barrier changes of subbelts, secondly, distinctions of a vegetation cover in different geomorphological conditions (small and average river valleys, northern slopes, etc.). Divisions of the legend of the second level correspond to dynamic series of units of the third level. Essential addition to it are block diagrams of dynamics of a vegetation cover.


Author(s):  
Patrick Colm Hogan

The introduction first sets out some preliminary definitions of sex, sexuality, and gender. It then turns from the sexual part of Sexual Identities to the identity part. A great deal of confusion results from failing to distinguish between identity in the sense of a category with which one identifies (categorial identity) and identity in the sense of a set of patterns that characterize one’s cognition, emotion, and behavior (practical identity). The second section gives a brief summary of this difference. The third and fourth sections sketch the relation of the book to social constructionism and queer theory, on the one hand, and evolutionary-cognitive approaches to sex, sexuality, and gender, on the other. The fifth section outlines the value of literature in not only illustrating, but advancing a research program in sex, sexuality, and gender identity. Finally, the introduction provides an overview of the chapters in this volume.


1980 ◽  
Vol 17 (04) ◽  
pp. 1133-1137 ◽  
Author(s):  
A. O. Pittenger

Two people independently and with the same distribution guess the location of an unseen object in n-dimensional space, and the one whose guess is closer to the unseen object is declared the winner. The first person announces his guess, but the second modifies his unspoken idea by moving his guess in the direction of the first guess and as close to it as possible. It is shown that if the distribution of guesses is rotationally symmetric about the true location of the unseen object, ¾ is the sharp lower bound for the success probability of the second guesser. If the distribution is fixed and the dimension increases, then for a certain class of distributions, the success probability approaches 1.


2005 ◽  
Vol 11 (5) ◽  
pp. 535-546 ◽  
Author(s):  
Anna Kondakov ◽  
Buko Lindner

Bacterial glycolipids are complex amphiphilic molecules which are, on the one hand, of utmost importance for the organization and function of bacterial membranes and which, on the other hand, play a major role in the activation of cells of the innate and adaptive immune system of the host. Already small alterations to their chemical structure may influence the biological activity tremendously. Due to their intrinsic biological heterogeneity [number and type of fatty acids, saccharide structures and substitution with for example, phosphate ( P), 2-aminoethyl-(pyro)phosphate groups ( P-Etn) or 4-amino-4-deoxyarabinose (Ara4N)], separation of the different components are a prerequisite for unequivocal chemical and nuclear magnetic resonance structural analyses. In this contribution, the structural information which can be obtained from heterogenous samples of glycolipids by Fourier transform (FT) ion cyclotron resonance mass spectrometric methods is described. By means of recently analysed complex biological samples, the possibilities of high-resolution electrospray ionization FT-MS are demonstrated. Capillary skimmer dissociation, as well as tandem mass spectrometry (MS/MS) analysis utilizing collision-induced dissociation and infrared multiphoton dissociation, are compared and their advantages in providing structural information of diagnostic importance are discussed.


1970 ◽  
Vol 37 (2) ◽  
pp. 267-270 ◽  
Author(s):  
D. Pnueli

A method is presented to obtain both upper and lower bound to eigenvalues when a variational formulation of the problem exists. The method consists of a systematic shift in the weight function. A detailed procedure is offered for one-dimensional problems, which makes improvement of the bounds possible, and which involves the same order of detailed computation as the Rayleigh-Ritz method. The main contribution of this method is that it yields the “other bound;” i.e., the one which cannot be obtained by the Rayleigh-Ritz method.


2021 ◽  
Vol 1 (15) ◽  
pp. 67-107
Author(s):  
Ines R. Artola

The aim of the present article is the analysis of Concerto for harpsichord and five instruments by Manuel de Falla – a piece which was dedicated by the composer to Wanda Landowska, an outstanding Polish harpsichord player. The piece was meant to commemorate the friendship these two artists shared as well as their collaboration. Written in the period of 1923-1926, the Concerto was the first composition in the history of 20th century music where harpsichord was the soloist instrument. The first element of the article is the context in which the piece was written. We shall look into the musical influences that shaped its form. On the one hand, it was the music of the past: from Cancionero Felipe Pedrell through mainly Bach’s polyphony to works by Scarlatti which preceded the Classicism (this influence is particularly noticeable in the third movement of the Concerto). On the other hand, it was music from the time of de Falla: first of all – Neo-Classicism and works by Stravinsky. The author refers to historical sources – critics’ reviews, testimonies of de Falla’s contemporaries and, obviously, his own remarks as to the interpretation of the piece. Next, Inés R. Artola analyses the score in the strict sense of the word “analysis”. In this part of the article, she quotes specific fragments of the composition, which reflect both traditional musical means (counterpoint, canon, Scarlatti-style sonata form, influence of old popular music) and the avant-garde ones (polytonality, orchestration, elements of neo-classical harmony).


2021 ◽  
Author(s):  
Rochelle Lieber

A lively introduction to morphology, this textbook is intended for undergraduates with relatively little background in linguistics. It shows students how to find and analyze morphological data and presents them with basic concepts and terminology concerning the mental lexicon, inflection, derivation, morphological typology, productivity, and the interfaces between morphology and syntax on the one hand and phonology on the other. By the end of the text students are ready to understand morphological theory and how to support or refute theoretical proposals. Providing data from a wide variety of languages, the text includes hands-on activities designed to encourage students to gather and analyse their own data. The third edition has been thoroughly updated with new examples and exercises. Chapter 2 now includes an updated detailed introduction to using linguistic corpora, and there is a new final chapter covering several current theoretical frameworks.


2021 ◽  
Vol 12 (8) ◽  
pp. 2161-2179
Author(s):  
Daiane Maria de Genaro Chiroli ◽  
Raíza Conde Coradazi ◽  
Fabio Jose Ceron Branco ◽  
Yslene Rocha Kachba ◽  
Franciely Velozo Aragão ◽  
...  

Healthcare logistics play an important role in management, being attributed the activities of acquisition, distribution and movement of materials, professionals and patients. This work aims to develop a study, using the healthcare logistics in the movement of patients in the third health region of Paraná, proposing a linear programming problem that will pass through a computational simulation, considering the existing demands and constraints in the system, aiming to optimize the flow of patients from this region. The present study developed four mathematical models, based on demands and constraints followed by linear programming in order to find the best possible solution for the flow of patients from the third health region of the state of Paraná. The study developed reached its goal of optimization, generating an economy in the transportation of patients. Through the analysis of the results, it is concluded that the model that best suits the presented problem is the one of costs minimization, since the one of vehicles presented higher costs. Possibly the model that minimizes the vehicles would bring better results if the vehicles were not outsourced, but of the Ponta Grossa City Hall (PMPG). Was possible to verify the importance of the theme, especially when referring to the flow of patients in the health services due to the lack of studies with this specific approach. Even with the scarcity of data, it is possible to notice the potential for improvements on this patient transport system.


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