Bidirectional communication using delay coupled chaotic directly modulated semiconductor lasers

Chaotic synchronization of two directly modulated semiconductor lasers with negative delayed optoelectronic feedback is investigated and this scheme is found to be useful for e±cient bidirectional communication between the lasers. A symmetric bidirec- tional coupling is identified as a suitable method for isochronal synchronization of such lasers. The optimum values of coupling and feedback strength that can provide maxi- mum quality of synchronization are identified. This method is successfully employed for encoding/decoding both analog and digital messages. The importance of a symmetric coupling is demonstrated by studying the variation of decoding efficiency with respect to asymmetric coupling.

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.

Puzzle game online running on a bidirectional communication framework based on Node.js and Socket.io

Máster Universitario en Ingeniería Informática (Escuela Universitaria de Informática)

Coordination between mid-term maintenance outage decisions and short-term security-constrained scheduling in smart distribution systems

Distribution systems are the first volunteers experiencing the benefits of smart grids. The smart grid concept impacts the internal legislation and standards in grid-connected and isolated distribution systems. Demand side management, the main feature of smart grids, acquires clear meaning in low voltage distribution systems. In these networks, various coordination procedures are required between domestic, commercial and industrial consumers, producers and the system operator. Obviously, the technical basis for bidirectional communication is the prerequisite of developing such a coordination procedure. The main coordination is required when the operator tries to dispatch the producers according to their own preferences without neglecting its inherent responsibility. Maintenance decisions are first determined by generating companies, and then the operator has to check and probably modify them for final approval. In this paper the generation scheduling from the viewpoint of a distribution system operator (DSO) is formulated. The traditional task of the DSO is securing network reliability and quality. The effectiveness of the proposed method is assessed by applying it to a 6-bus and 9-bus distribution system.

Gestão do deslastre de cargas: Évora como caso de estudo

Dissertação para obtenção do grau de Mestre em Engenharia Electrotécnica na Área de Especialização de Energia

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In the last years, the classical view of glial cells (in particular of astrocytes) as a simple supportive cell for neurons has been replaced by a new vision in which glial cells are active elements of the brain. Such a new vision is based on the existence of a bidirectional communication between astrocytes and neurons at synaptic level. Indeed, perisynaptic processes of astrocytes express active G-protein-coupled receptors that are able (1) to sense neurotransmitters released from the synapse during synaptic activity, (2) to increase cytosolic levels of calcium, and (3) to stimulate the release of gliotransmitters that in turn can interact with the synaptic elements. The mechanism(s) by which astrocytes can release gliotransmitter has been extensively studied during the last years. Many evidences have suggested that a fraction of astrocytes in situ release neuroactive substances both with calcium-dependent and calcium-independent mechanism(s); whether these mechanisms coexist and under what physiological or pathological conditions they occur, it remains unclear. However, the calcium-dependent exocytotic vesicular release has received considerable attention due to its potential to occur under physiological conditions via a finely regulated way. By releasing gliotransmitters in millisecond time scale with a specific vesicular apparatus, astrocytes can integrate and process synaptic information and control or modulate synaptic transmission and plasticity.

Unidireccionalitat i bidireccionalitat en les xarxes socials dels museus catalans

L’objectiu general d’aquest treball és analitzar les xarxes socials dels museus catalans registrats per a veure si les utilitzen com a un canal de comunicació unidireccional o bidireccional

Selective protection of the cerebellum against intracerebroventricular LPS is mediated by local melatonin synthesis

Although melatonin is mainly produced by the pineal gland, an increasing number of extra-pineal sites of melatonin synthesis have been described. We previously demonstrated the existence of bidirectional communication between the pineal gland and the immune system that drives a switch in melatonin production from the pineal gland to peripheral organs during the mounting of an innate immune response. In the present study, we show that acute neuroinflammation induced by lipopolysaccharide (LPS) injected directly into the lateral ventricles of adult rats reduces the nocturnal peak of melatonin in the plasma and induces its synthesis in the cerebellum, though not in the cortex or hippocampus. This increase in cerebellar melatonin content requires the activation of nuclear factor kappa B (NF-κB), which positively regulates the expression of the key enzyme for melatonin synthesis, arylalkylamine N-acetyltransferase (AA-NAT). Interestingly, LPS treatment led to neuronal death in the hippocampus and cortex, but not in the cerebellum. This privileged protection of cerebellar cells was abrogated when G-protein-coupled melatonin receptors were blocked by the melatonin antagonist luzindole, suggesting that the local production of melatonin protects cerebellar neurons from LPS toxicity. This is the first demonstration of a switch between pineal and extra-pineal melatonin production in the central nervous system following a neuroinflammatory response. These results have direct implications concerning the differential susceptibility of specific brain areas to neuronal death.

Lipopolysaccharide-Induced Sickness Behaviour Evaluated in Different Models of Anxiety and Innate Fear in Rats

The fact that there is a complex and bidirectional communication between the immune and nervous systems has been well demonstrated. Lipopolysaccharide (LPS), a component of gram-negative bacteria, is widely used to systematically stimulate the immune system and generate profound physiological and behavioural changes, also known as sickness behaviour (e.g. anhedonia, lethargy, loss of appetite, anxiety, sleepiness). Different ethological tools have been used to analyse the behavioural modifications induced by LPS; however, many researchers analysed only individual tests, a single LPS dose or a unique ethological parameter, thus leading to disagreements regarding the data. In the present study, we investigated the effects of different doses of LPS (10, 50, 200 and 500 mu g/kg, i.p.) in young male Wistar rats (weighing 180200 g; 89 weeks old) on the ethological and spatiotemporal parameters of the elevated plus maze, light-dark box, elevated T maze, open-field tests and emission of ultrasound vocalizations. There was a dose-dependent increase in anxiety-like behaviours caused by LPS, forming an inverted U curve peaked at LPS 200 mu g/kg dose. However, these anxiety-like behaviours were detected only by complementary ethological analysis (stretching, grooming, immobility responses and alarm calls), and these reactions seem to be a very sensitive tool in assessing the first signs of sickness behaviour. In summary, the present work clearly showed that there are resting and alertness reactions induced by opposite neuroimmune mechanisms (neuroimmune bias) that could lead to anxiety behaviours, suggesting that misunderstanding data could occur when only few ethological variables or single doses of LPS are analysed. Finally, it is hypothesized that this bias is an evolutionary tool that increases animals security while the body recovers from a systemic infection.

Role of BDNF secretion and signaling in the activity-dependent refinement of synaptic connections

Neuronal networks exhibit diverse types of plasticity, including the activity-dependent regulation of synaptic functions and refinement of synaptic connections. In addition, continuous generation of new neurons in the “adult” brain (adult neurogenesis) represents a powerful form of structural plasticity establishing new connections and possibly implementing pre-existing neuronal circuits (Kempermann et al, 2000; Ming and Song, 2005). Neurotrophins, a family of neuronal growth factors, are crucially involved in the modulation of activity-dependent neuronal plasticity. The first evidence for the physiological importance of this role evolved from the observations that the local administration of neurotrophins has dramatic effects on the activity-dependent refinement of synaptic connections in the visual cortex (McAllister et al, 1999; Berardi et al, 2000; Thoenen, 1995). Moreover, the local availability of critical amounts of neurotrophins appears to be relevant for the ability of hippocampal neurons to undergo long-term potentiation (LTP) of the synaptic transmission (Lu, 2004; Aicardi et al, 2004). To achieve a comprehensive understanding of the modulatory role of neurotrophins in integrated neuronal systems, informations on the mechanisms about local neurotrophins synthesis and secretion as well as ditribution of their cognate receptors are of crucial importance. In the first part of this doctoral thesis I have used electrophysiological approaches and real-time imaging tecniques to investigate additional features about the regulation of neurotrophins secretion, namely the capability of the neurotrophin brain-derived neurotrophic factor (BDNF) to undergo synaptic recycling. In cortical and hippocampal slices as well as in dissociated cell cultures, neuronal activity rapidly enhances the neuronal expression and secretion of BDNF which is subsequently taken up by neurons themselves but also by perineuronal astrocytes, through the selective activation of BDNF receptors. Moreover, internalized BDNF becomes part of the releasable source of the neurotrophin, which is promptly recruited for activity-dependent recycling. Thus, we described for the first time that neurons and astrocytes contain an endocytic compartment competent for BDNF recycling, suggesting a specialized form of bidirectional communication between neurons and glia. The mechanism of BDNF recycling is reminiscent of that for neurotransmitters and identifies BDNF as a new modulator implicated in neuro- and glio-transmission. In the second part of this doctoral thesis I addressed the role of BDNF signaling in adult hippocampal neurogenesis. I have generated a transgenic mouse model to specifically investigate the influence of BDNF signaling on the generation, differentiation, survival and connectivity of newborn neurons into the adult hippocampal network. I demonstrated that the survival of newborn neurons critically depends on the activation of the BDNF receptor TrkB. The TrkB-dependent decision regarding life or death in these newborn neurons takes place right at the transition point of their morphological and functional maturation Before newborn neurons start to die, they exhibit a drastic reduction in dendritic complexity and spine density compared to wild-type newborn neurons, indicating that this receptor is required for the connectivity of newborn neurons. Both the failure to become integrated and subsequent dying lead to impaired LTP. Finally, mice lacking a functional TrkB in the restricted population of newborn neurons show behavioral deficits, namely increased anxiety-like behavior. These data suggest that the integration and establishment of proper connections by newly generated neurons into the pre-existing network are relevant features for regulating the emotional state of the animal.

Optimization of Arq Parameters of Stanag 5066 for the HFDVL Modem

The reliability of bidirectional communication link can be guaranteed with Automatic Repeat Request Procedures (ARQ). The standard STANAG 5066 describes the ARQ procedure for HF communications that can either be applied to existing HF physical layers modems or adapted to future physical layer designs. In this contribution the physical layer parameters of an HF modem (HFDVL), developed by the authors over the last decade, are chosen to optimize the performance of the ARQ procedure described in STANAG 5066. Besides the interleaving length, constellation size and coding type, the OFDM-based HFDVL modem permits the selection of the number of receiver antennas. It will be shown that this parameter gives additional degrees of freedom and permits reliable communication over low SNR HF communication links.

Introducción de las plataformas tecnológicas 2.0 y la innovación abierta en la estrategia empresarial: estudio del sector de componentes electrónicos

Este proyecto se encuadra dentro de los estudios de impacto que están produciendo en las empresas el desarrollo e incorporación de las nuevas tecnologías, y más concretamente la implantación de las aplicaciones provenientes de la denominada web 2.0. Se conoce con este nombre a las herramientas web que permiten una comunicación bidireccional, es decir, el usuario y la empresa pueden intercambiar opiniones, de manera que el usuario adquiere un nuevo papel más protagonista, presentando ideas, aclaraciones, gustos, críticas...que son tenidas en cuenta por la empresa para realizar su actividad. De esta manera se ha roto con el modelo anterior donde el usuario solo podía consultar la información de una página web, era simple receptor de la información. El objetivo de este estudio es conocer cómo las empresas están incorporando estas tecnologías 2.0 a su estrategia empresarial, y cómo términos como innovación abierta o co-creación están tomando mayor importancia en el entorno empresarial gracias a estas nuevas tecnologías. Si bien existen estudios a nivel de consultoría que generalmente aportan información sobre cuáles son las plataformas 2.0 más utilizadas en el mundo empresarial, no se han encontrado hasta ahora estudios que vinculen estas plataformas entre ellas y con la estructura empresarial, para poder definir un perfil de la organización que trabaja con ellas o el nivel de madurez de la incorporación de estas tecnologías en las organizaciones. Analizar cualitativamente estos aspectos, significa estudiar los nuevos conceptos incorporados a las tecnologías 2.0 en la empresa. Un análisis cuantitativo nos llevaría a estudiar de manera práctica que tipo de recursos y en qué cantidad se están utilizando y su vinculación con la estructura de la organización. Para ello: En una primera parte, nos centraremos en las diferentes formas en las que se puede acceder a Internet, y a continuación enfocaremos el estudio en los dispositivos móviles que nos permiten la conexión desde cualquier lugar y en cualquier instante. Con esto conseguiremos tener una situación actual del mercado de las TIC y veremos cómo las empresas han ido construyendo nuevas políticas para cambiar su estrategia con el fin de estar presentes en los nuevos dispositivos móviles y no perder cuota de mercado. Tras ello, veremos porqué conceptos como el de innovación abierta y proceso de co-creación han sido posibles gracias a la implantación de las tecnologías 2.0 en el ámbito empresarial, facilitando que la empresa y el usuario final cooperen y vayan de la mano en una misma dirección; la empresa se surte de las aportaciones que los usuarios ofrecen, y por otra parte el usuario se siente valorado por la empresa para conseguir la meta final. Es aquí donde comprobaremos la transformación que ha sufrido la empresa en sus distintos sectores departamentales (marketing, ventas, recursos humanos y atención al cliente) como consecuencia de la incorporación de las herramientas 2.0 al mundo laboral. Por todo ello, se enumerarán los distintos usos que realizan las empresas de las redes social más habituales, y además se describirán las principales herramientas y/o aplicaciones para monitorizar las redes sociales que servirán a la empresa para hacer un seguimiento de las mismas. La segunda parte del proyecto será un caso práctico y servirá para ofrecer una visión más real del estado actual de las empresas y su relación con las redes sociales. Para la recopilación de los datos se han escogido las empresas que pertenecen al sector de la “Fabricación de productos informáticos, electrónicos y ópticos”. En cuento a las redes sociales elegidas, han sido Facebook y Twitter. Este estudio práctico nos hará entender mejor el impacto directo que tienen las redes sociales en la actividad diaria de las empresas. Finalmente se realizarán una serie de consideraciones a modo de directrices que servirán para tratar de entender cómo se están utilizando las redes sociales en el entorno empresarial y cuál puede ser la manera más óptima de utilizarlas según el estudio presentado. ABSTRACT. This project is part of the impact studies arisen in companies by the development and incorporation of new technologies and, specifically, by the implementation of applications from the so-called web 2.0. That is how we call the web tools that allow bidirectional communication, this is, user and company can exchange opinions, in such a way that users acquire a leading role, submitting ideas, explanations, preferences, criticism... considered by the company when performing its activities. This way, we have broken with the previous model, where users could only check information from a web page and were simple information recipients. The objective of this study is to get to know how companies are incorporating these technologies 2.0 to their business strategy and how terms such as open innovation or co-creation are becoming more important in the business sphere thanks to these new technologies. Even if there are consulting studies that generally provide information about which are the platforms 2.0 more used in the business world, no studies have been found until now that link such platforms among them and with the business structure, in order to define a profile of the organization that works with them or the level of development of the incorporation of these technologies in the organizations. A qualitative analysis of these aspects involves studying the new concepts incorporated to technologies 2.0 by companies. A qualitative analysis would lead us to study in a practical manner what kind of resources and what amount are being used and their relation with the organization structure. Therefore: First, we will focus on the different ways to gain access to the Internet and, afterwards, we will focus the study on mobile devices that allow us to be connected everywhere any time. This way, we will manage to obtain a present situation of the ICT market and we will see how companies have constructed new policies to change their strategy in order to be present in the new mobile devices without losing their market share. Later, we will review why concepts such as open innovation and co-creation process have been possible thanks to the implementation of technologies 2.0 in the business environment, facilitating that companies and final users cooperate and walk hand in hand in the same direction; companies stock up on the contributions offered by users and, on the other hand, users feel appreciated by companies in the achievement of the final goal. Here we will confirm the transformation suffering by companies in different department sectors (marketing, sales, human resources and customer service) as a result of the incorporation of tools 2.0 to the work environment. Therefore, we will enumerate the different uses that companies make of the most common social networks, describing the main tools and/or applications to monitor social networks used by companies to follow them up. The second part of the project will be a case study to offer a more real vision of the present status of companies and their relation with social networks. To collect the data, we have selected companies from the “Manufacture of computer, electronic and optical products” industry. The social networks chosen are Facebook and Twitter. This case study will help us to get a better understanding of the direct impact of social networks in companies’ daily activity. Finally, we will offer a series of considerations and guidelines to try to understand how are social networks being used in the business environment and what can be the most suitable manner to use them according to this study.

Mixed synapses discovered and mapped throughout mammalian spinal cord.

Previously, synaptic activity in the spinal cord of adult mammals was attributed exclusively to chemical neurotransmission. In this study, evidence was obtained for the existence, relative abundance, and widespread distribution of "mixed" (chemical and electrical) synapses on neurons throughout the spinal cords of adult mammals. Using combined confocal microscopy and "grid-mapped freeze fracture," 36 mixed synapses containing 88 "micro" gap junctions (median = 45 connexons) were found and mapped to 33 interneurons and motor neurons in Rexed laminae III-IX in cervical, thoracic, and lumbosacral spinal cords of adult male and female rats. Gap junctions were adjacent to presumptive active zones, where even small gap junctions would be expected to increase synaptic efficacy. Two morphological types of mixed synapse were discerned. One type contained distinctive active zones consisting of "nested" concentric toroidal deformations of pre- and postsynaptic membranes, which, because of their unusual topology, were designated as "synaptic sombreros." A second type had gap junctions adjacent to active zones consisting of broad, flat, shallow indentations of the plasma membrane. Morphometric analysis indicates that mixed synapses correspond to 3-5% of all synapses on the somata and proximal dendrites, but, because of their subcellular location and morphology, they could represent 30-100% of excitatory synapses. The relative abundance of mixed synapses on several classes of neurons in spinal cords of adult rats suggests that mixed synapses provide important but previously unrecognized pathways for bidirectional communication between neurons in the mammalian central nervous system.

Electronic booklet: vision of teachers and guardians of Basic School Students of Galicia

This research here described explores the first phase of a research project whose aim is to introduce a new form of collaboration and communication among the Family and School through an Electronic Booklet (EB), in Spain, in the Galician schools. The EB appears to meet the growing needs of collaboration between the school and the family, promoting the teaching learning process and educational success, supported by the Information and Communication Technologies (ICT). Through a questionnaire we sought to obtain the perceptions of teachers and parents regarding the adoption of an EB. Both groups stressed the importance of communication between the school and the family and expressed interest in EB, as bidirectional communication tool.

Customer involvement in new service development

This case study aims at filling the research gap in the literature, by researching how customers experience customer involvement in new service development, in addition to giving insight on what are the organisational customers’ motivations to become involved in service development. These subjects are studied by conducting three interviews. The thesis gives a review of previous findings regarding customer-driven new service development, customer involvement, customer roles, modes of involvement, communication in the involvement process, what is the role of customer engagement and what are the motivational drivers for customers. The thesis also explains what new service development is and makes a distinction between new service development and new service design. The results revealed that organisational customers want to be involved throughout the development process, with active involvement in the beginning and end phases. Moreover, customers prefer face-to-face methods and active and bidirectional communication throughout the process. The findings propose seven motivational factors, a new framework for customer-driven new service development and communication process map. The managerial implications list five themes for service providers to take into consideration when involving customers to the service development process.