Towards the optimal Bayes classifier using an extended self-organising map

In this paper, we propose an extended self-organising learning scheme, in which both distance measure and neighbourhood function have been replaced by the neuron's posterior probabilities. Updating of weights is within a limited but fixed sized neighbourhood of the winner. Each unit will converge to one component of a mixture distribution of input samples, so that an optimal pattern classifier can be formed. The proposed learning scheme can be used to train other forms of unsupervised networks, such as radial-basis-function networks. An application example on textured image segmentation is presented

Self-organising maps : statistical analysis, treatment and applications.

This thesis presents some substantial theoretical analyses and optimal treatments of Kohonen's self-organising map (SOM) algorithm, and explores the practical application potential of the algorithm for vector quantisation, pattern classification, and image processing. It consists of two major parts. In the first part, the SOM algorithm is investigated and analysed from a statistical viewpoint. The proof of its universal convergence for any dimensionality is obtained using a novel and extended form of the Central Limit Theorem. Its feature space is shown to be an approximate multivariate Gaussian process, which will eventually converge and form a mapping, which minimises the mean-square distortion between the feature and input spaces. The diminishing effect of the initial states and implicit effects of the learning rate and neighbourhood function on its convergence and ordering are analysed and discussed. Distinct and meaningful definitions, and associated measures, of its ordering are presented in relation to map's fault-tolerance. The SOM algorithm is further enhanced by incorporating a proposed constraint, or Bayesian modification, in order to achieve optimal vector quantisation or pattern classification. The second part of this thesis addresses the task of unsupervised texture-image segmentation by means of SOM networks and model-based descriptions. A brief review of texture analysis in terms of definitions, perceptions, and approaches is given. Markov random field model-based approaches are discussed in detail. Arising from this a hierarchical self-organised segmentation structure, which consists of a local MRF parameter estimator, a SOM network, and a simple voting layer, is proposed and is shown, by theoretical analysis and practical experiment, to achieve a maximum likelihood or maximum a posteriori segmentation. A fast, simple, but efficient boundary relaxation algorithm is proposed as a post-processor to further refine the resulting segmentation. The class number validation problem in a fully unsupervised segmentation is approached by a classical, simple, and on-line minimum mean-square-error method. Experimental results indicate that this method is very efficient for texture segmentation problems. The thesis concludes with some suggestions for further work on SOM neural networks

Descriptive analysis of online roulette gamblers: segmentation of different gamblers based on their behavior using data mining algorithms

Dissertation presented as the partial requirement for obtaining a Master's degree in Data Science and Advanced Analytics, specialization in Data ScienceThe popularity of gambling activities has been increasing over the last decades, with onlinebased gambling being a key driver of its growth due to the ease of accessing online platforms. Consequently, there is a severe concern that the negative social impact of gambling arises, and regulatory agencies are identifying and managing those effects. In this context, a potential solution to address those effects is based on the concept of 'Responsible Gambling', which means playing consciously, with complete control of time and money. The present study aims to segment online gamblers based on their playing behaviors, differentiating groups as much as possible and ultimately identifying a cluster with players of concern. This is achieved using unsupervised learning algorithms such as K-Means, Hierarchical Clustering, or Self-Organizing Maps. The information on which this project is based reflects the activity on some of the Portuguese online gambling platforms over 2019. Available data covers multiple aspects such as the gambling institution, type of gambling, player identification, each player's total bets, and the following outcomes of it

Artificial Intelligence in geospatial analysis: applications of self-organizing maps in the context of geographic information science.

A thesis submitted in partial fulfillment of the requirements for the degree of Doctor in Information Management, specialization in Geographic Information SystemsThe size and dimensionality of available geospatial repositories increases every day, placing additional pressure on existing analysis tools, as they are expected to extract more knowledge from these databases. Most of these tools were created in a data poor environment and thus rarely address concerns of efficiency, dimensionality and automatic exploration. In addition, traditional statistical techniques present several assumptions that are not realistic in the geospatial data domain. An example of this is the statistical independence between observations required by most classical statistics methods, which conflicts with the well-known spatial dependence that exists in geospatial data. Artificial intelligence and data mining methods constitute an alternative to explore and extract knowledge from geospatial data, which is less assumption dependent. In this thesis, we study the possible adaptation of existing general-purpose data mining tools to geospatial data analysis. The characteristics of geospatial datasets seems to be similar in many ways with other aspatial datasets for which several data mining tools have been used with success in the detection of patterns and relations. It seems, however that GIS-minded analysis and objectives require more than the results provided by these general tools and adaptations to meet the geographical information scientist‟s requirements are needed. Thus, we propose several geospatial applications based on a well-known data mining method, the self-organizing map (SOM), and analyse the adaptations required in each application to fulfil those objectives and needs. Three main fields of GIScience are covered in this thesis: cartographic representation; spatial clustering and knowledge discovery; and location optimization.(...

Architecture incorporated : authorship, anonymity, and collaboration in postwar modernism

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Architecture, 2018.Cataloged from PDF version of thesis.Includes bibliographical references (pages 305-344).A broad transformation occurred in the scale and scope of professional architectural practice in the United States in the decades after World War II. My dissertation explores this shift, in particular the rise of the body of collaborative and team-based methods of production that would come to be labeled as corporate architectural practice. An exploration of these practices reveals a climate of speculation in the postwar period on the corporation as a social and institutional form, and a widespread interest in the potentials of anonymous and collective methods to reshape the nature and objects of architectural production. Tracing the history of these collaborative approaches from progressive project to the critique of the corporate, the dissertation challenges the historiographic methods premised on singular authorship that have governed existing interpretations of postwar modernism. While there exists a growing body of work on architecture produced for corporations in the postwar period, far less critical attention has been paid to its corollary: the corporate production of architecture itself. Despite the dominant role of large firms within mainstream architectural practice in the United States, a comprehensive account has yet to be written of the motivations for and growth of such practices after 1945, the shifting economic and political conditions which underlay their production, and the problematic reception of their work by architectural critics after the 1970s, predicated on notions of signature and authorship which remained essentially unchanged despite these radical shifts in the nature of production. The dissertation proposes a cultural and discursive history of corporate architectural practice, from its origins and international extension to its built products and their reception within the architectural field. I explore these transformations in architecture through the history of The Architects Collaborative (TAC), founded in 1945 as an experiment in team-based design methods by seven young practitioners together with German émigré Walter Gropius. Despite the extensive historiography of Gropius and his work prior to 1945, there is as yet no detailed history of TAC itself, the largest architectural firm in the U.S. by the 1970s and the collective body through which Gropius practiced for the last twenty-five years of his career. An exploration of the firm's origins and expansion, its sustained legacy of work in the Middle East and Europe in the decades after World War II, and its eventual demise in 1995 reveals the contested stakes around questions of anonymity, authorship, and expertise at the heart of the U.S. architectural corporation and its continuing global impact up to the present.by Michael Kubo.Ph. D

Organization and Abstraction: The Architecture of Skidmore, Owings & Merrill from 1936 to 1956

This dissertation examines the history of the architecture firm, Skidmore, Owings & Merrill (SOM) between 1936 and 1956. While focusing on the birth and growth of SOM, this study attempts to position the firm in a larger historical development of the United States in the mid-twentieth century. While Louis Skidmore and Nathaniel A. Owings established the firm in 1936, the dissertation begins at the beginning of the Great Depression in 1929. During the 1930s, Skidmore and Owings learned critical lessons from industrial designers about the significance of the public as well as how to attract their attention. The founders discovered the importance of investigating people's reactions to certain forms and spaces, mainly working on small shops and exhibition halls. During WWII, SOM worked on prefabricated houses in the town of Oak Ridge, TN, which was part of the Manhattan Project. While working confidentially for the military for about three years, SOM mastered diverse kinds of building technology and gained experience with the various programs necessary for a conventional town. In addition, the firm constructed a modern architecture-engineering firm, which could handle complex architectural and engineering projects. As a result of their previous experience, SOM evolved into a leader in designing glass and steel office buildings after WWII, refining the architectural language it had discovered during the war. In the 1950s, the firm continued designing and constructing large town projects for American military and other corporations throughout the world. This dissertation records the shifts in the profession of architecture in each historical context throughout the mid-twentieth century. The first three chapters cover the years from 1929 to 1939, 1939 to 1945, and 1946 to 1956 respectively. The fourth chapter addresses the architecture community's perception of SOM and the firm's organizational characteristics. This dissertation investigates how SOM attempted to modernize architecture as a whole, responding to new materials as well as to the spatial and cultural conditions of the world

Hierarchical overlapped SOM's for pattern classification

We develop a multilayer overlapped self-organizing maps (SOM's) with limited structure adaptation capabilities, and associated learning scheme for labeled pattern classification applications. The learning algorithm consists of the standard unsupervised SOM learning of synaptic weights as well as the supervised learning vector quantization (LVQ) 2 learning. As higher layer SOM's overlap, the final classification is made by fusing the classifications of top-level overlapped SOM's. We obtained the best results ever reported for any SOM-based numerals classification system

Architectural design, 1954-1972.

This thesis examines the architectural magazine's contribution to the writing of modern architectural history using the magazine Architectural Design (AD) as a case study. There are four main narratives to this research, one "grand" and three "micro"; The overarching grand narrative (or meta-narrative) is the proposal to replace the existing art historical formulation of architectural history with a more holistic understanding of history based on power struggles in the field of architecture. This strategy is derived from an application of Pierre Bourdieu's theoretical framework to the field of architectural cultural production. The position of the architectural magazine as an institution in the construction of the architectural profession, and the ever-changing definition of architecture is one underlying micro-narrative. The introduction discusses the role that the architectural magazine played in the emergence of the modern architectural profession, alongside other institutions, specifically the academy and professional bodies. The central, and largest, micro-narrative is a critical history of the magazine Architectural Design from 1954 to 1972. Brief biographies of its editors and a background to the magazine from its inception in 1930 up to 1953 precede this by way of contextualisation. This history of AD discusses the content and context of the magazine and traces its shift from a professional architectural magazine to an autonomous. "little" magazine, focussing on several key structural themes that underpin the magazine. Throughout, the role that AD played in the promotion of the post-war neo-avant-garde, in particular the New Brutalists and Archigram, is documented and the relationships between the small circle of people privileged to produce and contribute to the magazine, and AD's rivalry with the Architectural Review are highlighted. The final micro-narrative is a reading of post-war modem architectural history from 1954 to 1972 through the pages of AD, tracing the rise and demise of modem architecture in terms of three defining shifts from the period evident in the magazine: "high to low"; "building to architecture"; and "hard to soft". This period also coincides exactly with the life of the Pruitt Igoe housing blocks in SI. Louis whose demolition, according to Jencks, represented the death of modern architecture. A growing post-modern sensibility in architecture is manifest in the magazine through an increasing resistance to modernist thinking. This study consciously employs post-modern methodologies to a period of modern architecture in an attempt to disturb modernist mythologies that have ossified into history