Fault tolerant decentralised K-Means clustering for asynchronous large-scale networks

The K-Means algorithm for cluster analysis is one of the most influential and popular data mining methods. Its straightforward parallel formulation is well suited for distributed memory systems with reliable interconnection networks, such as massively parallel processors and clusters of workstations. However, in large-scale geographically distributed systems the straightforward parallel algorithm can be rendered useless by a single communication failure or high latency in communication paths. The lack of scalable and fault tolerant global communication and synchronisation methods in large-scale systems has hindered the adoption of the K-Means algorithm for applications in large networked systems such as wireless sensor networks, peer-to-peer systems and mobile ad hoc networks. This work proposes a fully distributed K-Means algorithm (EpidemicK-Means) which does not require global communication and is intrinsically fault tolerant. The proposed distributed K-Means algorithm provides a clustering solution which can approximate the solution of an ideal centralised algorithm over the aggregated data as closely as desired. A comparative performance analysis is carried out against the state of the art sampling methods and shows that the proposed method overcomes the limitations of the sampling-based approaches for skewed clusters distributions. The experimental analysis confirms that the proposed algorithm is very accurate and fault tolerant under unreliable network conditions (message loss and node failures) and is suitable for asynchronous networks of very large and extreme scale.

Non-uniform data distribution for communication-efficient parallel clustering

Global communicationrequirements andloadimbalanceof someparalleldataminingalgorithms arethe major obstacles to exploitthe computational power of large-scale systems. This work investigates how non-uniform data distributions can be exploited to remove the global communication requirement and to reduce the communication costin parallel data mining algorithms and, in particular, in the k-means algorithm for cluster analysis. In the straightforward parallel formulation of the k-means algorithm, data and computation loads are uniformly distributed over the processing nodes. This approach has excellent load balancing characteristics that may suggest it could scale up to large and extreme-scale parallel computing systems. However, at each iteration step the algorithm requires a global reduction operationwhichhinders thescalabilityoftheapproach.Thisworkstudiesadifferentparallelformulation of the algorithm where the requirement of global communication is removed, while maintaining the same deterministic nature ofthe centralised algorithm. The proposed approach exploits a non-uniform data distribution which can be either found in real-world distributed applications or can be induced by means ofmulti-dimensional binary searchtrees. The approachcanalso be extended to accommodate an approximation error which allows a further reduction ofthe communication costs. The effectiveness of the exact and approximate methods has been tested in a parallel computing system with 64 processors and in simulations with 1024 processing element

Dynamic group communication for large-scale parallel data mining

Exascale systems are the next frontier in high-performance computing and are expected to deliver a performance of the order of 10^18 operations per second using massive multicore processors. Very large- and extreme-scale parallel systems pose critical algorithmic challenges, especially related to concurrency, locality and the need to avoid global communication patterns. This work investigates a novel protocol for dynamic group communication that can be used to remove the global communication requirement and to reduce the communication cost in parallel formulations of iterative data mining algorithms. The protocol is used to provide a communication-efficient parallel formulation of the k-means algorithm for cluster analysis. The approach is based on a collective communication operation for dynamic groups of processes and exploits non-uniform data distributions. Non-uniform data distributions can be either found in real-world distributed applications or induced by means of multidimensional binary search trees. The analysis of the proposed dynamic group communication protocol has shown that it does not introduce significant communication overhead. The parallel clustering algorithm has also been extended to accommodate an approximation error, which allows a further reduction of the communication costs. The effectiveness of the exact and approximate methods has been tested in a parallel computing system with 64 processors and in simulations with 1024 processing elements.

Efficient group communication for large-scale parallel clustering

Global communication requirements and load imbalance of some parallel data mining algorithms are the major obstacles to exploit the computational power of large-scale systems. This work investigates how non-uniform data distributions can be exploited to remove the global communication requirement and to reduce the communication cost in iterative parallel data mining algorithms. In particular, the analysis focuses on one of the most influential and popular data mining methods, the k-means algorithm for cluster analysis. The straightforward parallel formulation of the k-means algorithm requires a global reduction operation at each iteration step, which hinders its scalability. This work studies a different parallel formulation of the algorithm where the requirement of global communication can be relaxed while still providing the exact solution of the centralised k-means algorithm. The proposed approach exploits a non-uniform data distribution which can be either found in real world distributed applications or can be induced by means of multi-dimensional binary search trees. The approach can also be extended to accommodate an approximation error which allows a further reduction of the communication costs.

Antecedents of travellers' electronic word-of-mouth communication

Electronic word-of-mouth (eWOM) is recognised as a means of interpersonal communication and a powerful marketing tool. However, previous studies have focussed on related motivations, and limited attention has been given to understanding the antecedents of eWOM communication behaviour in the travel industry. This study proposes a full and partial mediation model, which brings together for the first time three key antecedents: adoption of electronic communication technology, consumer dis/satisfaction with travel consumption experience, and subjective norm. The model aims to understand the impact of these antecedents on travellers' attitude towards eWOM communication and intention to use eWOM communication media. The data were collected from international travellers (n = 524), and structural equation modelling is used to test the conceptual framework. The findings of the study suggest that overall attitude towards eWOM communication partially mediates the impact of the traveller's adoption of electronic communication technology and subjective norm, and fully mediates the impact of consumer dis/satisfaction with travel consumption experience on travellers' intention to use eWOM communication media.

Multimodal Literacy as a form of Communication : What is the state of the students at Dalarna University multimodal literacy?

Literacy is an invaluable asset to have, and has allowed for communication, documentation and the spreading of ideas since the beginning of the written language. With technological advancements, and new possibilities to communicate, it is important to question the degree to which people’s abilities to utilise these new methods have developed in relation to these emerging technologies. The purpose of this bachelor’s thesis is to analyse the state of students’ at Dalarna University mulitimodal literacy, as well as their experience of multimodality in their education. This has led to the two main research questions: What is the state of the students at Dalarna University multimodal literacy? And: How have the students at Dalarna University experienced multimodality in education? The paper is based on a mixed-method study that incorporates both a quantitative and qualitative aspect to it. The main thrust of the research paper is, however, based on a quantitative study that was conducted online and emailed to students via their program coordinators. The scope of the research is in audio-visual modes, i.e. audio, video and images, while textual literacy is presumed and serves as an inspiration to the study. The purpose of the study is to analyse the state of the students’ multimodal literacy and their experience of multimodality in education. The study revealed that the students at Dalarna University have most skill in image editing, while not being very literate in audio or video editing. The students seem to have had mediocre experience creating meaning through multimodality both in private use and in their respective educational institutions. The study also reveals that students prefer learning by means of video (rather than text or audio), yet are not able to create meaning (communicate) through it.

Exploratory study of corporate social responsibility: blogs as a communication tool to enhance company-stakeholders relationships

O conceito de responsabilidade social corporativa (RSE) evoluiu gradualmente do objetivo de satisfazer as expectativas dos acionistas para o cumprimento das expectativas das partes interessadas. Tornou-se um conceito amplamente aceitado e promovido como as empresas enfrentam maiores pressões de atores internos e externos para cumprir objetivos sociais maiores. Assim, elas cada vez mais comunicam sobre os esforços de responsabilidade social delas, a fim de fomentar a confiança e o envolvimento dos stakeholders. Mas o aumento da cidadania global e as novas tecnologias de informação e de comunicação – como as mídias sociaias – está criando uma paisagem desafiador para a comunicação RSE, se traduzindo em escrutínio e ceticismo do público. No entanto, também está criando novas oportunidades para as empresas compartilhar e interagir com as partes interessadas. O estudo analisa especificamente como os blogs corporativos dedicados à comunicação RSE conseguem melhorar as relações entre as empresas e as partes interessadas. Esta pesquisa exploratória da estrutura e das mensagens de 9 blogs corporativos, é baseada em um quadro de análise sobre comunicação RSE em plataformas de mídias sociais desenvolvido por Gomez e Chalmeta (2013). O quadro está melhorado e adaptado para blogs graças à literatura sobre comunicação RSE, mídias sociais e blogs corporativos. Os resultados demonstram que o uso de características de blogs como apresentação, conteúdo e interatividade, é diversificado e reflete estratégias diferentes de comunicação RSE. Blogs permitem às empresas aumentar a visibilidade da comunicação RSE, melhorar a credibilidade e a legitimidade dos esforços de responsabilidade social, e também trazer discussões com os stakeholders. No entanto, demonstramos que as características e recursos dos blogs raramente são totalmente desenvolvidos, sugerindo avenidas para a melhoria no campo da comunicação nas mídias sociais. Especificamente, o uso da interatividade para criar relações baseadas em diálogo entre empresas e stakeholders está até atrasado em relação à extensão das oportunidades oferecidas pelos blogs. Além disso, o grau de utilização das ferramentas de blogs determina a eficácia da comunicação de RSE 2.0 das empresas na criação de relações empresa-stakeholder.

How Communication experts express communicative competence

Este estudo teve por objetivo compreender como especialistas brasileiros em comunicação expressam sua competência comunicativa. Investigou-se um grupo de professores universitários de enfermagem, especialistas na área de comunicação, utilizando-se a seguinte pergunta norteadora: Como você expressa sua competência comunicativa? Os entrevistados referiram expressar sua competência comunicativa vivenciando-a em sua vida profissional e em sua rotina diária, ouvindo outras pessoas, percebendo a comunicação não-verbal, validando a compreensão de mensagens, quebrando barreiras de comunicação, demonstrando afetividade e desenvolvendo o autoconhecimento. Os resultados obtidos a partir deste estudo nos permitiram compreender a comunicação como algo a ser aprendido, sentido e vivenciado, ou seja, percebendo as nossas próprias emoções e sentimentos assim como os de outras pessoas, tanto no cuidado em enfermagem quanto em ações da vida diária.

Dental caries of lifetime residents in Baixo Guandu, Brazil, fluoridated since 1953: a brief communication

Objectives: This study aimed to verify the dental caries prevalence in Baixo Guandu, the first Brazilian city to fluoridate its public water supplies; to compare the findings with the data from the national survey; and also to compare the prevalence in the 12-year-old age group with the data obtained before the beginning of the fluoridation. Methods: All the lifetime residents aged 5, 12, 15 to 19, and 35 to 44 years old were clinically examined (World Health Organization). Results: The means of dmft/DMFT were lower than in the Brazilian population living in fluoridated communities. The DMFT Index in 12-year-old residents decreased between 1953 and 2005 from 8.61 to 1.55. Conclusions: The addition of fluoride to public water supplies was an important ally in the improvement of the oral health of Baixo Guandu inhabitants.

GRAMMAR and COMMUNICATION IN PORTUGUESE AS A FOREIGN LANGUAGE A Study in the Context of Teletandem Interactions

This paper presents a study about the role of grammar in on-line interactions conducted in Portuguese and in English, between Brazilian and English-speaking interactants, with the aim of teaching Portuguese as a foreign language (PFL). The interactions occurred by means of chat and the MSN Messenger, and generated audio and video data for language analysis. Grammar is dealt with from two perspectives, an inductive and a deductive approach, so as to investigate the relevance of systematization of grammar rules in the process of learning PFL in teletandem interactions.

Organizational communication and innovation in micro and small companies: a study on the application of the Innovation Radar

This paper is a study on corporate communication and the ability to innovate in small businesses. The guiding question seeks to respond whether organizational communication is able to make progress and / or support innovation in micro and small companies, and the main objective is to analyze the relationship between innovation and organizational communication. It was applied the case study method and document research for interpreting a diagnosis instru- ment called “Innovation Radar” in a small business company located in the countryside of São Paulo state. The diagnosis is made based on assessment dimensions aimed at checking the maturity and the degree of innovation in micro and small companies. By evaluating these di- mensions it was possible to build analytical frameworks and highlight the influence of corporate communication in promoting innovation. The results indicate that every dimension of the “In- novation Radar” can improve their performance by means of corporate communication.

Working Experience and Librarians' Knowledge of Information and Communication Technologies (ICTs) in Nigerian University Libraries

This paper discuses the influence of librarians' years of working experience and sources of acquisition of ICTs' knowledge and skills. The study is based on 169 librarians working in thirteen university libraries in the universities of six states located in the South-South zone of Nigeria. The purpose of the paper is to find out if years of working experience has an effect on librarians' sources/means of acquisition of ICT knowledge and skills. The questionnaires used were answered by two categories of librarians. Those with longer years of experience – 16 years and above and those with fewer years of working experience. It was concluded that librarians with fewer years of working experience explore means of acquiring ICTs knowledge and skills more than librarians with more years of working experience. It was recommended that librarians with longer years of working experience develop more interest in sources through which they can acquire ICT knowledge and skills.

Semiotics of Communication: From Semiosis of Nature to Culture

Communication Studies currently undergoes a crisis of paradigms that requires an ontological review that must begin with a debate about the conditions of possibility of every communicational phenomena. In this article we argue that semiosis offers a conceptual framework that allows for the study of communication as qualitative action. Semiosis, or the action of the sign, is here defined as a fundamental process based on perception that models the world of species, creating cognition and culture. At the core of semiosis are dynamic structures that the authors have defined as 'ontological diagrams'. The first purpose of Semiotics of Communication is to understand how these modeling systems evolve ontologically and phylogenically, producing, in the case of human culture, means of communication ever more varied and technologically advanced.

Memory hierarchy and data communication in heterogeneous reconfigurable SoCs

The miniaturization race in the hardware industry aiming at continuous increasing of transistor density on a die does not bring respective application performance improvements any more. One of the most promising alternatives is to exploit a heterogeneous nature of common applications in hardware. Supported by reconfigurable computation, which has already proved its efficiency in accelerating data intensive applications, this concept promises a breakthrough in contemporary technology development. Memory organization in such heterogeneous reconfigurable architectures becomes very critical. Two primary aspects introduce a sophisticated trade-off. On the one hand, a memory subsystem should provide well organized distributed data structure and guarantee the required data bandwidth. On the other hand, it should hide the heterogeneous hardware structure from the end-user, in order to support feasible high-level programmability of the system. This thesis work explores the heterogeneous reconfigurable hardware architectures and presents possible solutions to cope the problem of memory organization and data structure. By the example of the MORPHEUS heterogeneous platform, the discussion follows the complete design cycle, starting from decision making and justification, until hardware realization. Particular emphasis is made on the methods to support high system performance, meet application requirements, and provide a user-friendly programmer interface. As a result, the research introduces a complete heterogeneous platform enhanced with a hierarchical memory organization, which copes with its task by means of separating computation from communication, providing reconfigurable engines with computation and configuration data, and unification of heterogeneous computational devices using local storage buffers. It is distinguished from the related solutions by distributed data-flow organization, specifically engineered mechanisms to operate with data on local domains, particular communication infrastructure based on Network-on-Chip, and thorough methods to prevent computation and communication stalls. In addition, a novel advanced technique to accelerate memory access was developed and implemented.

Innovative architecture of on-board and on-ground radio systems for space communication

The radio communication system is one of the most critical system of the overall satellite platform: it often represents the only way of communication, between a spacecraft and the Ground Segment or among a constellation of satellites. This thesis focuses on specific innovative architectures for on-board and on-ground radio systems. In particular, this work is an integral part of a space program started in 2004 at the University of Bologna, Forlì campus, which led to the completion of the microsatellite ALMASat-1, successfully launched on-board the VEGA maiden flight. The success of this program led to the development of a second microsatellite, named ALMASat-EO, a three-axis stabilized microsatellite able to capture images of the Earth surface. Therefore, the first objective of this study was focused on the investigation of an innovative, efficient and low cost architecture for on-board radio communication systems. The TT&C system and the high data rate transmitter for images downlink design and realization are thoroughly described in this work, together with the development of the embedded hardware and the adopted antenna systems. Moreover, considering the increasing interest in the development of constellations of microsatellite, in particular those flying in close formations, a careful analysis has been carried out for the development of innovative communication protocols for inter-satellite links. Furthermore, in order to investigate the system aspects of space communications, a study has been carried out at ESOC having as objective the design, implementation and test of two experimental devices for the enhancement of the ESA GS. Thus, a significant portion of this thesis is dedicated to the description of the results of a method for improving the phase stability of GS radio frequency equipments by means of real-time phase compensation and a new way to perform two antennas arraying tracking using already existing ESA tracking stations facilities.