Query routing in cooperative semi-structured peer-to-peer information retrieval networks

Conventional web search engines are centralised in that a single entity crawls and indexes the documents selected for future retrieval, and the relevance models used to determine which documents are relevant to a given user query. As a result, these search engines suffer from several technical drawbacks such as handling scale, timeliness and reliability, in addition to ethical concerns such as commercial manipulation and information censorship. Alleviating the need to rely entirely on a single entity, Peer-to-Peer (P2P) Information Retrieval (IR) has been proposed as a solution, as it distributes the functional components of a web search engine – from crawling and indexing documents, to query processing – across the network of users (or, peers) who use the search engine. This strategy for constructing an IR system poses several efficiency and effectiveness challenges which have been identified in past work. Accordingly, this thesis makes several contributions towards advancing the state of the art in P2P-IR effectiveness by improving the query processing and relevance scoring aspects of a P2P web search. Federated search systems are a form of distributed information retrieval model that route the user’s information need, formulated as a query, to distributed resources and merge the retrieved result lists into a final list. P2P-IR networks are one form of federated search in routing queries and merging result among participating peers. The query is propagated through disseminated nodes to hit the peers that are most likely to contain relevant documents, then the retrieved result lists are merged at different points along the path from the relevant peers to the query initializer (or namely, customer). However, query routing in P2P-IR networks is considered as one of the major challenges and critical part in P2P-IR networks; as the relevant peers might be lost in low-quality peer selection while executing the query routing, and inevitably lead to less effective retrieval results. This motivates this thesis to study and propose query routing techniques to improve retrieval quality in such networks. Cluster-based semi-structured P2P-IR networks exploit the cluster hypothesis to organise the peers into similar semantic clusters where each such semantic cluster is managed by super-peers. In this thesis, I construct three semi-structured P2P-IR models and examine their retrieval effectiveness. I also leverage the cluster centroids at the super-peer level as content representations gathered from cooperative peers to propose a query routing approach called Inverted PeerCluster Index (IPI) that simulates the conventional inverted index of the centralised corpus to organise the statistics of peers’ terms. The results show a competitive retrieval quality in comparison to baseline approaches. Furthermore, I study the applicability of using the conventional Information Retrieval models as peer selection approaches where each peer can be considered as a big document of documents. The experimental evaluation shows comparative and significant results and explains that document retrieval methods are very effective for peer selection that brings back the analogy between documents and peers. Additionally, Learning to Rank (LtR) algorithms are exploited to build a learned classifier for peer ranking at the super-peer level. The experiments show significant results with state-of-the-art resource selection methods and competitive results to corresponding classification-based approaches. Finally, I propose reputation-based query routing approaches that exploit the idea of providing feedback on a specific item in the social community networks and manage it for future decision-making. The system monitors users’ behaviours when they click or download documents from the final ranked list as implicit feedback and mines the given information to build a reputation-based data structure. The data structure is used to score peers and then rank them for query routing. I conduct a set of experiments to cover various scenarios including noisy feedback information (i.e, providing positive feedback on non-relevant documents) to examine the robustness of reputation-based approaches. The empirical evaluation shows significant results in almost all measurement metrics with approximate improvement more than 56% compared to baseline approaches. Thus, based on the results, if one were to choose one technique, reputation-based approaches are clearly the natural choices which also can be deployed on any P2P network.

Para una crítica de la educación democrática

El propósito central de este trabajo consiste en hacer un análisis crítico de la idea de educación democrática. Como hilo conductor se discute la tesis desarrollada por Amy Gutmann, según la cual, la educación democrática tiene como fin garantizar la reproducción consciente de la sociedad. En este contexto, la tesis que se defiende afirma que la educación democrática exige, además de los principios de no represión y la no discriminación desarrollados por Gutmann, un principio de reconocimiento, que articule la orientación de las acciones educativas a fuentes de normatividad asociadas con una interpretación intersubjetivista de la autonomía, de manera que se puedan generar más elementos de juicio, sobre todo, aquellos incorporados en las dimensiones moral, ética, política, legal y social de la persona, al momento de proponer prácticas educativas encaminadas a la formación de una ciudadanía participativa y crítica. Para esto se propone una interpretación que integra las perspectivas deliberativa y agonal de la democracia, se defiende que la expresión clave del ejercicio de la ciudadanía democrática es la participación, que el ejercicio de la participación tiene por condición la realización de la autonomía personal, por lo cual, en la parte final se elabora una lectura intersubjetivista de la autonomía, a partir de los trabajos de Axel Honneth y Rainer Forst.

Un aporte a la comprensión de las estrategias emergentes en las organizaciones a través del concepto de improvisación y la metáfora musical

Este trabajo se inscribe en uno de los grandes campos de los estudios organizacionales: la estrategia. La perspectiva clásica en este campo promovió la idea de que proyectarse hacia el futuro implica diseñar un plan (una serie de acciones deliberadas). Avances posteriores mostraron que la estrategia podía ser comprendida de otras formas. Sin embargo, la evolución del campo privilegió en alguna medida la mirada clásica estableciendo, por ejemplo, múltiples modelos para ‘formular’ una estrategia, pero dejando en segundo lugar la manera en la que esta puede ‘emerger’. El propósito de esta investigación es, entonces, aportar al actual nivel de comprensión respecto a las estrategias emergentes en las organizaciones. Para hacerlo, se consideró un concepto opuesto —aunque complementario— al de ‘planeación’ y, de hecho, muy cercano en su naturaleza a ese tipo de estrategias: la improvisación. Dado que este se ha nutrido de valiosos aportes del mundo de la música, se acudió al saber propio de este dominio, recurriendo al uso de ‘la metáfora’ como recurso teórico para entenderlo y alcanzar el objetivo propuesto. Los resultados muestran que 1) las estrategias deliberadas y las emergentes coexisten y se complementan, 2) la improvisación está siempre presente en el contexto organizacional, 3) existe una mayor intensidad de la improvisación en el ‘como’ de la estrategia que en el ‘qué’ y, en oposición a la idea convencional al respecto, 4) se requiere cierta preparación para poder improvisar de manera adecuada.

Rethinking Le Corbusier: Urban Design and History

It is generally assumed that Le Corbusier’s urban planning made a break with the past, and that the public spaces designed by him had nothing to do with anything that existed before – a conviction fostered by both the innovative character of his proposals and by the proliferation in his manifestos of watchwords that mask any evocation of the past – words like civilisation machiniste, l’esprit nouveau, l’architecture de demain. However, in his writings, Le Corbusier often mentioned the powerful analogy that exists between the architecture of other times and the logic of modern production. Vers une architecture, for example, contains a mixture of photographs showing silos, cars, aeroplanes, ships (i.e. the fruits of 19th and 20th century civil architecture and mechanical engineering) alongside photographs of Greek and Roman buildings. While Le Corbusier, at the end of the 1920s, claimed “I have only one teacher: the past; only one education: the study of the past”, a series of sketches in the first volume of the Œuvre complète, done during his youth at the archaeological sites visited during his Grand Tour, shows that his interest in the past went far beyond a simple reference.

A qualidade da comunicação dos técnicos e auxiliares de ressonância magnética num serviço de radiologia: um programa de intervenção

O presente estudo preliminar teve como finalidade analisar a qualidade da comunicação dos técnicos e auxiliares de ação médica nos exames de Ressonância Magnética, partindo da observação da linguagem verbal e não-verbal. Por analogia com outros domínios, desenvolveu-se um programa de intervenção que incidiu na formação dos técnicos e auxiliares ação médica do Serviço de Radiologia de um hospital público. Recorrendo a uma grelha de observação, avaliou-se o efeito do treino de competências no aumento dos comportamentos adequados durante as Ressonâncias Magnéticas. De uma forma geral, os resultados analisados demonstraram que a formação teve um efeito significativo nos técnicos e nos auxiliares das ressonâncias magnéticas, originando mudanças positivas no local de trabalho, tal como o desenvolvimento de uma relação mais adequada com os doentes que potencie o sucesso do diagnóstico; "Analysis of communication quality of technicians and auxiliaries of MRI radiology service" Abstract: With this preliminary study, we intented to analyze the quality of communication in magnetic resonance imaging exams, starting from the observation of verbal and non-verbal language. By analogy with other areas, it was developed an intervention program focused on the training of technicians and operational assistants of the Radiology service of public hospital. Using a grid note, we assessed the effect of skills training in the increased of appropriate behaviour during the MRIs. In General, the results examined showed that the training had a significant effect on operational assistants and technicians of MRIs, resulting in positive changes in the workplace, such as developing a proper relationship with patients to promote the success of the diagnosis.