959 resultados para Digital Communication
Resumo:
The ability to use Software Defined Radio (SDR) in the civilian mobile applications will make it possible for the next generation of mobile devices to handle multi-standard personal wireless devices and ubiquitous wireless devices. The original military standard created many beneficial characteristics for SDR, but resulted in a number of disadvantages as well. Many challenges in commercializing SDR are still the subject of interest in the software radio research community. Four main issues that have been already addressed are performance, size, weight, and power. ^ This investigation presents an in-depth study of SDR inter-components communications in terms of total link delay related to the number of components and packet sizes in systems based on Software Communication Architecture (SCA). The study is based on the investigation of the controlled environment platform. Results suggest that the total link delay does not linearly increase with the number of components and the packet sizes. The closed form expression of the delay was modeled using a logistic function in terms of the number of components and packet sizes. The model performed well when the number of components was large. ^ Based upon the mobility applications, energy consumption has become one of the most crucial limitations. SDR will not only provide flexibility of multi-protocol support, but this desirable feature will also bring a choice of mobile protocols. Having such a variety of choices available creates a problem in the selection of the most appropriate protocol to transmit. An investigation in a real-time algorithm to optimize energy efficiency was also performed. Communication energy models were used including switching estimation to develop a waveform selection algorithm. Simulations were performed to validate the concept.^
Resumo:
Voice communication systems such as Voice-over IP (VoIP), Public Switched Telephone Networks, and Mobile Telephone Networks, are an integral means of human tele-interaction. These systems pose distinctive challenges due to their unique characteristics such as low volume, burstiness and stringent delay/loss requirements across heterogeneous underlying network technologies. Effective quality evaluation methodologies are important for system development and refinement, particularly by adopting user feedback based measurement. Presently, most of the evaluation models are system-centric (Quality of Service or QoS-based), which questioned us to explore a user-centric (Quality of Experience or QoE-based) approach as a step towards the human-centric paradigm of system design. We research an affect-based QoE evaluation framework which attempts to capture users' perception while they are engaged in voice communication. Our modular approach consists of feature extraction from multiple information sources including various affective cues and different classification procedures such as Support Vector Machines (SVM) and k-Nearest Neighbor (kNN). The experimental study is illustrated in depth with detailed analysis of results. The evidences collected provide the potential feasibility of our approach for QoE evaluation and suggest the consideration of human affective attributes in modeling user experience.
Resumo:
Communication has become an essential function in our civilization. With the increasing demand for communication channels, it is now necessary to find ways to optimize the use of their bandwidth. One way to achieve this is by transforming the information before it is transmitted. This transformation can be performed by several techniques. One of the newest of these techniques is the use of wavelets. Wavelet transformation refers to the act of breaking down a signal into components called details and trends by using small waveforms that have a zero average in the time domain. After this transformation the data can be compressed by discarding the details, transmitting the trends. In the receiving end, the trends are used to reconstruct the image. In this work, the wavelet used for the transformation of an image will be selected from a library of available bases. The accuracy of the reconstruction, after the details are discarded, is dependent on the wavelets chosen from the wavelet basis library. The system developed in this thesis takes a 2-D image and decomposes it using a wavelet bank. A digital signal processor is used to achieve near real-time performance in this transformation task. A contribution of this thesis project is the development of DSP-based test bed for the future development of new real-time wavelet transformation algorithms.
Resumo:
Multiple physiological systems regulate the electric communication signal of the weakly electric gymnotiform fish, Brachyhypopomuspinnicaudatus. Fish were injected with neuroendocrine probes which identified pharmacologically relevant serotonin (5-HT) receptors similar to the mammalian 5-HT1AR and 5-HT2AR. Peptide hormones of the hypothalamic-pituitary-adrenal/interrenal axis also augment the electric waveform. These results indicate that the central serotonergic system interacts with the hypothalamic-pituitaryinterrenal system to regulate communication signals in this species. The same neuroendocrine probes were tested in females before and after introducing androgens to examine the relationship between sex steroid hormones, the serotonergic system, melanocortin peptides, and EOD modulations. Androgens caused an increase in female B. pinnicaudatus responsiveness to other pharmacological challenges, particularly to the melanocortin peptide adrenocorticotropic hormone (ACTH). A forced social challenge paradigm was administered to determine if androgens are responsible for controlling the signal modulations these fish exhibit when they encounter conspecifics. Males and females responded similarly to this social challenge construct, however introducing androgens caused implanted females to produce more exaggerated responses. These results confirm that androgens enhance an individual's capacity to produce an exaggerated response to challenge, however another unidentified factor appears to regulate sex-specific behaviors in this species. These results suggest that the rapid electric waveform modulations B. pinnicaudatus produces in response to conspecifics are situation-specific and controlled by activation of different serotonin receptor types and the subsequent effect on release of pituitary hormones.
Resumo:
Hospitalized individuals are isolated from their familiar environment at the onset of illness. Those individuals who are non-communicative are detached from the world and from life, as they previously knew it. Although nurses have long since recognized the importance of communication, patients still report the lack of iy. This study was done to identify factors influencing critical care nurses to communicate with their noncommunicative patients. The overall results of the study indicate that nurses are aware of the importance of verbal communication with patients who may be intubated, paralyzed, unconscious, comatose or neurologically impaired and are not deterred by them. Despite these results, some significant observations emerged identified. CCRN certified nurses and nurses with more years of experience were less likely to have verbal communication with noncommunicative patients. Nurses with children, spouses and those working full-time were more likely to communicate with non-communicative patients.
Resumo:
The primary purpose of this thesis was to design a logical simulation of a communication sub block to be used in the effective communication of digital data between the host and the peripheral devices. The module designed is a Serial interface engine in the Universal Serial Bus that effectively controls the flow of data for communication between the host and the peripheral devices with the emphasis on the study of timing and control signals, considering the practical aspects of them. In this study an attempt was made to realize data communication in the hardware using the Verilog Hardware Description language, which is supported by most popular logic synthesis tools. Various techniques like Cyclic Redundancy Checks, bit-stuffing and Non Return to Zero are implemented in the design to provide enhanced performance of the module.
Resumo:
Nowadays the Distance Learning (DL) is in its fifth generation and New Information and Communication Technologies (NICT) mediate it. In this technological context it is then called Distance e-Learning (DeL). DeL has also in the e-books a potential interactive tool to the collaborative learning. So, this study was accomplished with the purpose of analyzing the e-books developed by SEDIS – Secretaria de Educação a Distância (Department of Distance Learning). This study was performed in two phases: Firstly it was done an exploratory study to check out the reading and the handling of digital e-learning material available to the student-users. These e-books are obtainable on SEDIS Moodle platform. Secondly, it was performed some analysis of an e-book sample by means of the heuristic evaluation. This research aims both to identify potential problems and give some suggestions to solve them. At last it is presented a final report with diagnosis and suggestions for a more applicable design in order to optimize the e-book by means of the distance e-learning usability guidelines
Resumo:
We quantify the error statistics and patterning effects in a 5x 40 Gbit/s WDM RZ-DBPSK SMF/DCF fibre link using hybrid Raman/EDFA amplification. We propose an adaptive constrained coding for the suppression of errors due to patterning effects. It is established, that this coding technique can greatly reduce the bit error rate (BER) value even for large BER (BER > 101). The proposed approach can be used in the combination with the forward error correction schemes (FEC) to correct the errors even when real channel BER is outside the FEC workspace.
Resumo:
En el presente artículo se reflexiona sobre los modos - dinámicos y cambiantes - en que la apropiación de las Tecnologías de Información y Comunicación (TIC) opera en la constitución de las desigualdades sociales y sobre las categorías utilizadas para comprenderlos. La reflexión se ilustra con los hallazgos de una investigación que compara la apropiación de las TIC por jóvenes de clases medias - altas y clases populares urbanas en el Gran La Plata. En el actual contexto de marcado crecimiento del acceso a la computadora e Internet, es preciso revisar las nociones de "brecha digital" y "nativos e inmigrantes digitales", superar resabios tecnologicistas y desplazar la mirada de los objetos a los procesos que resultan significativos para los propios actores: cómo se configuran las trayectorias de acceso; por qué se han convertido las TIC y ciertos saberes y habilidades en bienes de alta deseabilidad colectiva; qué procesos habilitan o permiten en el marco de una sociabilidad específica y qué diferencias logran así los actores suplir. De este modo, se espera contribuir a una evaluación cualitativa de las políticas públicas sobre el terreno "realmente existente" en que operan las desigualdades en la sociedad argentina contemporánea.
Resumo:
This paper focuses on the ties between social and digital inequalities among Argentinean youth. It uses a qualitative approach to explore different aspects of the everyday lives of adolescents, such as sociability, leisure time and family use of Information and Communication Technologies (ICTs), in order to assess the impact of the Connecting Equality Program (Programa Conectar Igualdad, PCI) on reducing digital inequalities and fostering social inclusion. What were the existing conditions of access for students and their families when the PCI was first implemented? What influence does the implementation of the PCI have on the individual, family and scholastic appropriation of ICTs? How does the use of computers and the Internet vary among youth? Has this large-scale incorporation of netbooks in schools, and especially homes and free time changed it in any way? Does the appropriation of ICTs through student participation in the PCI contribute to material and symbolic social inclusion? In order to answer these questions, we compare the processes of ICT appropriation among lower and middle class adolescents, focusing on the distinctive uses and meanings assigned to computers and the Internet by boys and girls in their daily lives. For this purpose we analyze data collected through semi-structured interviews in two schools in Greater La Plata, Argentina during 2012. The main findings show that in terms of access, skills and types of use, the implementation of the PCI has had a positive impact among lower class youth, guaranteeing access to their first computers and promoting the sharing of knowledge and digital skills with family members. Moreover, evidence of more diverse and intense use of ICTs among lower class students reveals the development of digital skills related to educational activities. Finally, in terms of sociability, having a personal netbook enables access to information and cultural goods which are very significant in generating ties and strengthening identities and social integration
Resumo:
En el presente artículo se reflexiona sobre los modos - dinámicos y cambiantes - en que la apropiación de las Tecnologías de Información y Comunicación (TIC) opera en la constitución de las desigualdades sociales y sobre las categorías utilizadas para comprenderlos. La reflexión se ilustra con los hallazgos de una investigación que compara la apropiación de las TIC por jóvenes de clases medias - altas y clases populares urbanas en el Gran La Plata. En el actual contexto de marcado crecimiento del acceso a la computadora e Internet, es preciso revisar las nociones de "brecha digital" y "nativos e inmigrantes digitales", superar resabios tecnologicistas y desplazar la mirada de los objetos a los procesos que resultan significativos para los propios actores: cómo se configuran las trayectorias de acceso; por qué se han convertido las TIC y ciertos saberes y habilidades en bienes de alta deseabilidad colectiva; qué procesos habilitan o permiten en el marco de una sociabilidad específica y qué diferencias logran así los actores suplir. De este modo, se espera contribuir a una evaluación cualitativa de las políticas públicas sobre el terreno "realmente existente" en que operan las desigualdades en la sociedad argentina contemporánea.
Resumo:
This paper focuses on the ties between social and digital inequalities among Argentinean youth. It uses a qualitative approach to explore different aspects of the everyday lives of adolescents, such as sociability, leisure time and family use of Information and Communication Technologies (ICTs), in order to assess the impact of the Connecting Equality Program (Programa Conectar Igualdad, PCI) on reducing digital inequalities and fostering social inclusion. What were the existing conditions of access for students and their families when the PCI was first implemented? What influence does the implementation of the PCI have on the individual, family and scholastic appropriation of ICTs? How does the use of computers and the Internet vary among youth? Has this large-scale incorporation of netbooks in schools, and especially homes and free time changed it in any way? Does the appropriation of ICTs through student participation in the PCI contribute to material and symbolic social inclusion? In order to answer these questions, we compare the processes of ICT appropriation among lower and middle class adolescents, focusing on the distinctive uses and meanings assigned to computers and the Internet by boys and girls in their daily lives. For this purpose we analyze data collected through semi-structured interviews in two schools in Greater La Plata, Argentina during 2012. The main findings show that in terms of access, skills and types of use, the implementation of the PCI has had a positive impact among lower class youth, guaranteeing access to their first computers and promoting the sharing of knowledge and digital skills with family members. Moreover, evidence of more diverse and intense use of ICTs among lower class students reveals the development of digital skills related to educational activities. Finally, in terms of sociability, having a personal netbook enables access to information and cultural goods which are very significant in generating ties and strengthening identities and social integration
Resumo:
This paper focuses on the ties between social and digital inequalities among Argentinean youth. It uses a qualitative approach to explore different aspects of the everyday lives of adolescents, such as sociability, leisure time and family use of Information and Communication Technologies (ICTs), in order to assess the impact of the Connecting Equality Program (Programa Conectar Igualdad, PCI) on reducing digital inequalities and fostering social inclusion. What were the existing conditions of access for students and their families when the PCI was first implemented? What influence does the implementation of the PCI have on the individual, family and scholastic appropriation of ICTs? How does the use of computers and the Internet vary among youth? Has this large-scale incorporation of netbooks in schools, and especially homes and free time changed it in any way? Does the appropriation of ICTs through student participation in the PCI contribute to material and symbolic social inclusion? In order to answer these questions, we compare the processes of ICT appropriation among lower and middle class adolescents, focusing on the distinctive uses and meanings assigned to computers and the Internet by boys and girls in their daily lives. For this purpose we analyze data collected through semi-structured interviews in two schools in Greater La Plata, Argentina during 2012. The main findings show that in terms of access, skills and types of use, the implementation of the PCI has had a positive impact among lower class youth, guaranteeing access to their first computers and promoting the sharing of knowledge and digital skills with family members. Moreover, evidence of more diverse and intense use of ICTs among lower class students reveals the development of digital skills related to educational activities. Finally, in terms of sociability, having a personal netbook enables access to information and cultural goods which are very significant in generating ties and strengthening identities and social integration
Resumo:
En el presente artículo se reflexiona sobre los modos - dinámicos y cambiantes - en que la apropiación de las Tecnologías de Información y Comunicación (TIC) opera en la constitución de las desigualdades sociales y sobre las categorías utilizadas para comprenderlos. La reflexión se ilustra con los hallazgos de una investigación que compara la apropiación de las TIC por jóvenes de clases medias - altas y clases populares urbanas en el Gran La Plata. En el actual contexto de marcado crecimiento del acceso a la computadora e Internet, es preciso revisar las nociones de "brecha digital" y "nativos e inmigrantes digitales", superar resabios tecnologicistas y desplazar la mirada de los objetos a los procesos que resultan significativos para los propios actores: cómo se configuran las trayectorias de acceso; por qué se han convertido las TIC y ciertos saberes y habilidades en bienes de alta deseabilidad colectiva; qué procesos habilitan o permiten en el marco de una sociabilidad específica y qué diferencias logran así los actores suplir. De este modo, se espera contribuir a una evaluación cualitativa de las políticas públicas sobre el terreno "realmente existente" en que operan las desigualdades en la sociedad argentina contemporánea.