scholarly journals Classification of bijections between 321- and 132-avoiding permutations

2008 ◽  
Vol DMTCS Proceedings vol. AJ,... (Proceedings) ◽  
Author(s):  
Anders Claesson ◽  
Sergey Kitaev

International audience It is well-known, and was first established by Knuth in 1969, that the number of 321-avoiding permutations is equal to that of 132-avoiding permutations. In the literature one can find many subsequent bijective proofs confirming this fact. It turns out that some of the published bijections can easily be obtained from others. In this paper we describe all bijections we were able to find in the literature and we show how they are related to each other (via "trivial'' bijections). Thus, we give a comprehensive survey and a systematic analysis of these bijections. We also analyze how many permutation statistics (from a fixed, but large, set of statistics) each of the known bijections preserves, obtaining substantial extensions of known results. We also give a recursive description of the algorithmic bijection given by Richards in 1988 (combined with a bijection by Knuth from 1969). This bijection is equivalent to the celebrated bijection of Simion and Schmidt (1985), as well as to the bijection given by Krattenthaler in 2001, and it respects 11 statistics (the largest number of statistics any of the bijections respect).


Ergodesign ◽  
2020 ◽  
Vol 2020 (2) ◽  
pp. 58-62
Author(s):  
Alexander Anishenko ◽  
Tatyana Krotenko ◽  
Dmitriy Erokhin

A systematic analysis of the concept of "sustainable development of the region" is carried out . The classification of factors that affect the process of sustainable development is given. A three -factor resource model for the formation of sustainable development of the region , including human, financial and raw materials, is described. The necessity of systematic monitoring as an element of regional development control is substantiated.



2013 ◽  
Vol 4 (2) ◽  
Author(s):  
Dušan Ignjatović ◽  
Nataša Ćuković Ignjatović ◽  
Milica Jovanović Popović

Serbia’s Law on Planning and Building has imposed the topics of energy efficiency in building sector, requiring adequate policy making and providing a starting point for improvement of the current situation in this field. Considering the fact that there are more than 3.200.000 housing units without any statistical classification a need arose for establishing a national building typology as a starting point for further decision making and appropriate activities definition regarding the existing housing stock. After joining EU TABULA (Typology Approach for Building Stock Energy Assessment) project, methodologies and approaches of the European countries have been analysed providing a common experience, at the same illustrating a need for identification and classification of local characteristics. In order to obtain adequate data a comprehensive survey has been conducted, providing a starting point for creation of typology. The National Typology has identified typical “model” buildings and defined the levels of improvement ranging from standard (according to the current law) to the low-energy level. The paper explains the methodology, procedures and local characteristics of the process and gives an insight in the activity describing the problems and potentials of the approach.



2019 ◽  
Vol 18 (2) ◽  
pp. 66-72
Author(s):  
Abhijit Bhowmik ◽  
AZM Ehtesham Chowdhury

The necessity for designing autonomous indexing tools to establish expressive and efficient means of describing musical media content is well recognized. Music genre classification systems are significant to manage and use music databases. This research paper proposes an enhanced method to automatically classify music into different genre using a machine learning approach and presents the insight and results of the application of the proposed scheme to the classification of a large set of The Bangla music content, a South-East Asian language rich with a variety of music genres developed over many centuries. Building upon musical feature extraction and decision-making techniques, we propose new features and procedures to achieve enhanced accuracy. We demonstrate the efficacy of the proposed method by extracting features from a dataset of hundreds of The Bangla music pieces and testing the automatic classification decisions. This is the first development of an automated classification technique applied specifically to the Bangla music to the best of our knowledge, while the superior accuracy of the method makes it universally applicable.



2020 ◽  
Vol 16 (3) ◽  
pp. 714-759
Author(s):  
Zuhra Z. Kuzeeva

The article is devoted to the classification analysis of the glazed ceramics of Derbent, originating from the materials of archaeological excavations (excavations XXVII and XXXIII), carried out in 2014-2015. in the city. The chronological framework of the study was presumably determined by the end of the VIII-X centuries. The relevance of the topic is characterized by the importance of studying the glazed ceramics of Derbent as a source of a large set of information (historical, cultural and socio-economic interactions of Derbent with a wide range of countries of the Near and Far Abroad).Typology of glazed ceramics in Derbent at the end of the 8th-10th centuries is considered in the article on the basis of modern methodological developments based on three main approaches to the study of any ceramics: the study of technology together with the morphology and decor of the dishes. All investigated ceramics, consisting of fragments of rims, bodies, bases and handles of vessels, are included in one large Section - Household ceramics. This section includes three sections, which are based on the analysis of the clay color of the shard (red clay, brown clay, beige clay ceramics), which determines the technology for the production of dishes. Based on the presence or absence of engobe on ceramics, two subsections are allocated in each department. The next division is the groups that are formed according to the degree of transparency of the opaque glaze. There are three of them: ceramics with transparent, translucent, opaque (dull) glaze. Within some groups, four subgroups are additionally distinguished, determined by the color of the glaze. According to the peculiarities of the additional decor, the types (overglaze, underglaze ornament) and subtypes (painting, engraving, combination of painting with engraving, relief ornament) of ceramics are distinguished. Thus, the characteristics of the glazed ceramics of Derbent from these excavations include: Section, department, sub-department, group, subgroup, type, subtype.



2011 ◽  
Vol DMTCS Proceedings vol. AO,... (Proceedings) ◽  
Author(s):  
Hoda Bidkhori

International audience In this paper we study finite Eulerian posets which are binomial or Sheffer. These important classes of posets are related to the theory of generating functions and to geometry. The results of this paper are organized as follows: (1) We completely determine the structure of Eulerian binomial posets and, as a conclusion, we are able to classify factorial functions of Eulerian binomial posets; (2) We give an almost complete classification of factorial functions of Eulerian Sheffer posets by dividing the original question into several cases; (3) In most cases above, we completely determine the structure of Eulerian Sheffer posets, a result stronger than just classifying factorial functions of these Eulerian Sheffer posets. We also study Eulerian triangular posets. This paper answers questions posed by R. Ehrenborg and M. Readdy. This research is also motivated by the work of R. Stanley about recognizing the \emphboolean lattice by looking at smaller intervals. Nous étudions les ensembles partiellement ordonnés finis (EPO) qui sont soit binomiaux soit de type Sheffer (deux notions reliées aux séries génératrices et à la géométrie). Nos résultats sont les suivants: (1) nous déterminons la structure des EPO Euleriens et binomiaux; nous classifions ainsi les fonctions factorielles de tous ces EPO; (2) nous donnons une classification presque complète des fonctions factorielles des EPO Euleriens de type Sheffer; (3) dans la plupart de ces cas, nous déterminons complètement la structure des EPO Euleriens et Sheffer, ce qui est plus fort que classifier leurs fonctions factorielles. Nous étudions aussi les EPO Euleriens triangulaires. Cet article répond à des questions de R. Ehrenborg and M. Readdy. Il est aussi motivé par le travail de R. Stanley sur la reconnaissance du treillis booléen via l'étude des petits intervalles.



2015 ◽  
Vol DMTCS Proceedings, 27th... (Proceedings) ◽  
Author(s):  
Emily Barnard ◽  
Emily Meehan ◽  
Shira Polster ◽  
Nathan Reading

International audience We construct universal geometric coefficients for the cluster algebra associated to the four-punctured sphere and obtain, as a by-product, the $g$ -vectors of cluster variables. We also construct the rational part of the mutation fan. These constructions rely on a classification of the allowable curves (the curves which can appear in quasi-laminations). The classification allows us to prove the Null Tangle Property for the four-punctured sphere, thus adding this surface to a short list of surfaces for which this property is known. The Null Tangle Property then implies that the shear coordinates of allowable curves are the universal coefficients. We compute these shear coordinates to obtain universal geometric coefficients. Nous construisons des coefficients géométriques universels pour l’algèbre amassée associée à la sphère privée de 4 points, et obtenons ce faisant les $g$-vecteurs des variables d’amas. Nous construisons aussi la partie rationnelle de l’éventail de mutation. Ces constructions reposent sur la classification des courbes admissibles (les courbes qui peuvent apparaître dans les quasi-laminations). Cette classification nous permet de prouver la “Null Tangle Property” pour la sphère privée de 4 points, ajoutant ainsi cette surface à la courte liste de surfaces pour lesquelles cette propriété est connue. La “Null Tangle Property” implique alors que les coordonnées de décalage des courbes admissibles sont les coefficients universels. Nous calculons ces coordonnées de décalage pour obtenir les coefficients géométriques universels.



2017 ◽  
Vol 29 (2) ◽  
pp. 680-693 ◽  
Author(s):  
Volker Nickeleit ◽  
Harsharan K. Singh ◽  
Parmjeet Randhawa ◽  
Cinthia B. Drachenberg ◽  
Ramneesh Bhatnagar ◽  
...  

Polyomavirus nephropathy (PVN) is a common viral infection of renal allografts, with biopsy-proven incidence of approximately 5%. A generally accepted morphologic classification of definitive PVN that groups histologic changes, reflects clinical presentation, and facilitates comparative outcome analyses is lacking. Here, we report a morphologic classification scheme for definitive PVN from the Banff Working Group on Polyomavirus Nephropathy, comprising nine transplant centers in the United States and Europe. This study represents the largest systematic analysis of definitive PVN undertaken thus far. In a retrospective fashion, clinical data were collected from 192 patients and correlated with morphologic findings from index biopsies at the time of initial PVN diagnosis. Histologic features were centrally scored according to Banff guidelines, including additional semiquantitative histologic assessment of intrarenal polyomavirus replication/load levels. In-depth statistical analyses, including mixed effects repeated measures models and logistic regression, revealed two independent histologic variables to be most significantly associated with clinical presentation: intrarenal polyomavirus load levels and Banff interstitial fibrosis ci scores. These two statistically determined histologic variables formed the basis for the definition of three PVN classes that correlated strongest with three clinical parameters: presentation at time of index biopsy, serum creatinine levels/renal function over 24 months of follow-up, and graft failure. The PVN classes 1–3 as described here can easily be recognized in routine renal biopsy specimens. We recommend using this morphologic PVN classification scheme for diagnostic communication, especially at the time of index diagnosis, and in scientific studies to improve comparative data analysis.



Author(s):  
Irina Tal ◽  
Gabriel-Miro Muntean

This chapter highlights the importance of Vehicular Ad-Hoc Networks (VANETs) in the context of smarter cities and roads, a topic that currently attracts significant academic, industrial, and governmental planning, research, and development efforts. In order for VANETs to become reality, a very promising avenue is to bring together multiple wireless technologies in the architectural design. Clustering can be employed in designing such a VANET architecture that successfully uses different technologies. Moreover, as clustering addresses some of VANETs' major challenges, such as scalability and stability, it seems clustering will have an important role in the desired vehicular connectivity in the cities and roads of the future. This chapter presents a comprehensive survey of clustering schemes in the VANET research area, covering aspects that have never been addressed before in a structured manner. The survey presented in this chapter provides a general classification of the clustering algorithms, presents some of the most advanced and latest algorithms in VANETs, and in addition, constitutes the only work in the literature to the best of authors' knowledge that also reviews the performance assessment of clustering algorithms.



2019 ◽  
Vol 9 (24) ◽  
pp. 5358 ◽  
Author(s):  
Shaohua Jiang ◽  
Liping Jiang ◽  
Yunwei Han ◽  
Zheng Wu ◽  
Na Wang

The expansion of scale and the increase of complexity of construction projects puts higher requirements on the level of collaboration among different stakeholders. How to realize better information interoperability among multiple disciplines and different software platforms becomes a key problem in the collaborative process. openBIM (building information model), as a common approach of information exchange, can meet the needs of information interaction among different software well and improve the efficiency and accuracy of collaboration. To the best of our knowledge, there is currently no comprehensive survey of openBIM approach in the context of the AEC (Architecture, Engineering & Construction) industry, this paper fills the gap and presents a literature review of openBIM. In this paper, the openBIM related standards, software platforms, and tools enabling information interoperability are introduced and analyzed comprehensively based on related websites and literature. Furthermore, engineering information interoperability research supported by openBIM is analyzed from the perspectives of information representation, information query, information exchange, information extension, and information integration. Finally, research gaps and future directions are presented based on the analysis of existing research. The systematic analysis of the theory and practice of openBIM in this paper can provide support for its further research and application.



Author(s):  
Andrew Kertesz

SUMMARY:A brief but comprehensive survey of classifying aphasia reveals that most investigators describe at least four major groups, conveniently labelled Broca's, Wernicke's, anomic and global. Conduction and transcortical aphasias are less generally described and modality specific syndromes rarely, if ever, exist purely. The controversy between unifiers and splitters continues but objective numerical taxonomy may solve some of the problems of classification.



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