Multi-user bidirectional communication using isochronal synchronisation of array of chaotic directly modulated semiconductor lasers

Isochronal synchronisation between the elements of an array of three mutually coupled directly modulated semiconductor lasers is utilized for the purpose of simultaneous bidirectional secure communication. Chaotic synchronisation is achieved by adding the coupling signal to the self feedback signal provided to each element of the array. A symmetric coupling is effective in inducing synchronisation between the elements of the array. This coupling scheme provides a direct link between every pair of elements thus making the method suitable for simultaneous bidirectional communication between them. Both analog and digital messages are successfully encrypted and decrypted simultaneously by each element of the array.

Communication mechanisms and middleware for distributed video surveillance

A new generation of advanced surveillance systems is being conceived as a collection of multi-sensor components such as video, audio and mobile robots interacting in a cooperating manner to enhance situation awareness capabilities to assist surveillance personnel. The prominent issues that these systems face are: the improvement of existing intelligent video surveillance systems, the inclusion of wireless networks, the use of low power sensors, the design architecture, the communication between different components, the fusion of data emerging from different type of sensors, the location of personnel (providers and consumers) and the scalability of the system. This paper focuses on the aspects pertaining to real-time distributed architecture and scalability. For example, to meet real-time requirements, these systems need to process data streams in concurrent environments, designed by taking into account scheduling and synchronisation. The paper proposes a framework for the design of visual surveillance systems based on components derived from the principles of Real Time Networks/Data Oriented Requirements Implementation Scheme (RTN/DORIS). It also proposes the implementation of these components using the well-known middleware technology Common Object Request Broker Architecture (CORBA). Results using this architecture for video surveillance are presented through an implemented prototype.

Upgrading a TCABR data analysis and acquisition system for remote participation using Java, XML, RCP and modern client/server communication/authentication

The TCABR data analysis and acquisition system has been upgraded to support a joint research programme using remote participation technologies. The architecture of the new system uses Java language as programming environment. Since application parameters and hardware in a joint experiment are complex with a large variability of components, requirements and specification solutions need to be flexible and modular, independent from operating system and computer architecture. To describe and organize the information on all the components and the connections among them, systems are developed using the extensible Markup Language (XML) technology. The communication between clients and servers uses remote procedure call (RPC) based on the XML (RPC-XML technology). The integration among Java language, XML and RPC-XML technologies allows to develop easily a standard data and communication access layer between users and laboratories using common software libraries and Web application. The libraries allow data retrieval using the same methods for all user laboratories in the joint collaboration, and the Web application allows a simple graphical user interface (GUI) access. The TCABR tokamak team in collaboration with the IPFN (Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, Universidade Tecnica de Lisboa) is implementing this remote participation technologies. The first version was tested at the Joint Experiment on TCABR (TCABRJE), a Host Laboratory Experiment, organized in cooperation with the IAEA (International Atomic Energy Agency) in the framework of the IAEA Coordinated Research Project (CRP) on ""Joint Research Using Small Tokamaks"". (C) 2010 Elsevier B.V. All rights reserved.

Multiple Pathways Analysis of Brain Functional Networks from EEG Signals: An Application to Real Data

In the present study, we propose a theoretical graph procedure to investigate multiple pathways in brain functional networks. By taking into account all the possible paths consisting of h links between the nodes pairs of the network, we measured the global network redundancy R (h) as the number of parallel paths and the global network permeability P (h) as the probability to get connected. We used this procedure to investigate the structural and dynamical changes in the cortical networks estimated from a dataset of high-resolution EEG signals in a group of spinal cord injured (SCI) patients during the attempt of foot movement. In the light of a statistical contrast with a healthy population, the permeability index P (h) of the SCI networks increased significantly (P < 0.01) in the Theta frequency band (3-6 Hz) for distances h ranging from 2 to 4. On the contrary, no significant differences were found between the two populations for the redundancy index R (h) . The most significant changes in the brain functional network of SCI patients occurred mainly in the lower spectral contents. These changes were related to an improved propagation of communication between the closest cortical areas rather than to a different level of redundancy. This evidence strengthens the hypothesis of the need for a higher functional interaction among the closest ROIs as a mechanism to compensate the lack of feedback from the peripheral nerves to the sensomotor areas.

Translation, Communication and 'Learning' : Experiences from teaching a master program in Viet Nam

In Vietnam, as in other Asian countries, co-operation with foreign universities plays an important role for the development of higher education. This paper is based on personal experiences from teaching a Swedish Master Programme in Education Science at Vietnam National University in Hanoi. Using theories developed by Lev Vygotsky and Donald Schon, the programme is explored as an inter-cultural learning process. Three aspects are focused upon. Firstly, the fact that communication between students and teachers is conducted with the help of translators who support both teachers and students in their attempt to understand and make themselves understood. Secondly, the expressed need to connect the ideas and techniques which are studied in the programme to the students´ professional worlds. Thirdly, the need to construct a framework wherein the students can inquire into their own situations and to encourage them to try new and more productive ways to deal with problems they are confronted with.

Nurses’ and patients’ communication in smoking cessation at nurse-led COPD clinics in primary health care

Background: Smokers with chronic obstructive pulmonary disease (COPD) have high nicotine dependence making it difficult to quit smoking. Motivational interviewing (MI) is a method that is used in stimulating motivation and behavioral changes. Objective: To describe smoking cessation communication between patients and registered nurses trained in MI in COPD nurse-led clinics in Swedish primary health care. Methods: A prospective observational study with structured quantitative content analyses of the communication between six nurses with basic education in MI and 13 patients in non-smoking consultations. Results: Only to a small extent did nurses’ evoke patients’ reasons for change, stimulate collaboration, and support patients’ autonomy. Nurses provided information, asked closed questions, and made simple reflections. Patients’ communicationwasmainly neutral and focusing on reasons for and against smoking. It was uncommon for patients to be committed and take steps toward smoking cessation. Conclusion: The nurses did not adhere to the principles of MI in smoking cessation, and the patients focused to a limited extent on how to quit smoking. Practice implications: To make patients more active, the nurses need more education and continuous training in motivational communication.

Crisis communication: organization's reactions to unexpected events

A reputação é considerada o ativo mais importante das empresas. Ela permite o estabelecimento de relações comerciais e garante um bom funcionamento da organização. Quando um evento inesperado surge, a reputação pode ser ameaçada. Os gerentes, líderes da organização, têm então que demonstrar reatividade e capacidade em responder as necessidades dos stakeholders, e capacidade de detectar e consertar as falhas dentro da organização através de um processo de aprendizagem, para evitar conseqüências negativas que poderiam danificar a reputação e impactar o desenvolvimento operacional da empresa. Através da comunicação de crise, observamos que depois da queda do avião AF 447, a companhia Air France adotou diferentes posturas adaptadas ao pedido dos stakeholders e ao grau de ameaça sofrido. Logo depois do acidente, a empresa decidiu adotar a estratégia do reconhecimento, assumindo uma responsabilidade simbólica e comunicando prioritariamente para as famílias das vitimas e para a mídia. Nas seguintes semanas ela utilizou a estratégia do silêncio que consiste em não comunicar diretamente a mídia. Finalmente, ela usou a estratégia do “bode expiatório” quando ela foi sujeita a ataques diretos. As reações da empresa somadas ao avanço das investigações judiciais revelaram falhas organizacionais “históricas” dentro da própria empresa, como por exemplo, a falta de comunicação entre pilotos e gerentes ou uma falha de sensibilidade técnica e operacional da parte dos gerentes. Apesar de problemas interno e externo, a Air France demonstrou que uma comunicação de crise bem gerenciada limita os impactos financeiros e de reputação. As conseqüências negativas sofridas pela companhia Air France foram limitadas.

Sistemas distribuídos aplicados à compressão e recuperação de imagens

Digital image processing is a field that demands great processing capacity. As such it becomes relevant to implement software that is based on the distribution of the processing into several nodes divided by computers belonging to the same network. Specifically discussed in this work are distributed algorithms of compression and expansion of images using the discrete cosine transform. The results show that the savings in processing time obtained due to the parallel algorithms in comparison to its sequential equivalents is a function that depends on the resolution of the image and the complexity of the involved calculation; that is efficiency is greater the longer the processing period is in terms of the time involved for the communication between the network points.

On the reliability of visual communication in vertebrate-dispersed fruits

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Logistics and trade facilitation between CARICOM and Central America

Includes bibliography.

Influence of mobility models in precision spray aided by wireless sensor networks

Precision Spray is a technique to increase performance of Precision Agriculture. This spray technique may be aided by a Wireless Sensor Network, however, for such approach, the communication between the agricultural input applicator vehicle and network is critical due to its proper functioning. Thus, this work analyzes how the number of nodes in a wireless sensor network, its type of distribution and different areas of scenario affects the performance of communication. We performed simulations to observe system's behavior changing to find the most fitted non-controlled mobility model to the system.

Dinâmica de constituição e eventos geradores em redes de colaboração científica: estudo exploratório entre relações de coautoria e em bancas de defesas de teses e dissertações na área da Ciências da Comunicação.

O estudo da dinâmica de constituição de uma rede visa identificar que tipos de eventos ocorreram nas conexões entre os nós que levaram a formação da estrutura atual da rede em análise. Entender esses eventos é entender as formas específicas e estratégias de conectividade que deram origem a rede. O presente trabalho tem por objetivo analisar esses eventos geradores com foco específico em redes de colaboração científica, considerando relações de coautoria e participação em bancas de defesas de teses e dissertações. Analisando mais de 11.000 documentos específicos da área das Ciências da Comunicação, propomos dois tipos característicos de eventos que pretendem explicar a dinâmica de formação das redes em análise.

Analog Signal Acquisition and Conditioning for Near-Field Capacitive Communication and Active Combined EEG-EIT Monitoring

The work of the present thesis is focused on the implementation of microelectronic voltage sensing devices, with the purpose of transmitting and extracting analog information between devices of different nature at short distances or upon contact. Initally, chip-to-chip communication has been studied, and circuitry for 3D capacitive coupling has been implemented. Such circuits allow the communication between dies fabricated in different technologies. Due to their novelty, they are not standardized and currently not supported by standard CAD tools. In order to overcome such burden, a novel approach for the characterization of such communicating links has been proposed. This results in shorter design times and increased accuracy. Communication between an integrated circuit (IC) and a probe card has been extensively studied as well. Today wafer probing is a costly test procedure with many drawbacks, which could be overcome by a different communication approach such as capacitive coupling. For this reason wireless wafer probing has been investigated as an alternative approach to standard on-contact wafer probing. Interfaces between integrated circuits and biological systems have also been investigated. Active electrodes for simultaneous electroencephalography (EEG) and electrical impedance tomography (EIT) have been implemented for the first time in a 0.35 um process. Number of wires has been minimized by sharing the analog outputs and supply on a single wire, thus implementing electrodes that require only 4 wires for their operation. Minimization of wires reduces the cable weight and thus limits the patient's discomfort. The physical channel for communication between an IC and a biological medium is represented by the electrode itself. As this is a very crucial point for biopotential acquisitions, large efforts have been carried in order to investigate the different electrode technologies and geometries and an electromagnetic model is presented in order to characterize the properties of the electrode to skin interface.

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.

Cooperative Wireless Systems

This Ph.D. dissertation reports on the work performed at the Wireless Communication Laboratory - University of Bologna and National Research Council - as well as, for six months, at the Fraunhofer Institute for Integrated Circuit (IIS) in Nürnberg. The work of this thesis is in the area of wireless communications, especially with regards to cooperative communications aspects in narrow-band and ultra-wideband systems, cooperative links characterization, network geometry, power allocation techniques,and synchronization between nodes. The underpinning of this work is devoted to developing a general framework for design and analysis of wireless cooperative communication systems, which depends on propagation environment, transmission technique, diversity method, power allocation for various scenarios and relay positions. The optimal power allocation for minimizing the bit error probability at the destination is derived. In addition, a syncronization algorithm for master-slave communications is proposed with the aim of jointly compensate the clock drift and offset of wireless nodes composing the network.