The High Frequency (HF) band, 3-30 MHz, is used when no infrastructure for long-range communications is available. New technology, such as digital signal processing enables higher data rate in the HF band, which in 2000s has resulted in increased commercial use. Reflection of radio waves in the ionosphere allows for beyond horizon communication, and are a unique property of the HF band. However, properties of the ionosphere are highly dependent of radiation from the sun, which varies with geographical location, season and time. The use of unmanned areal vehicle (UAV) has increased during the past years. In this project it is investigated if a HF transmitter can be placed on a small UAV platform. The objective is to get an estimation of the probabilities for successful HF transfer of real-time data from a small UAV. For example, the data could be sensor- or position data. When studying a complex problem having several parameters, such as a HF communication system, it is necessary to use the systems approach. This report illustrates the impact of size of the transmitting antenna, transmitter output power and bandwidth as well as different sources of noise and its levels. The results and analysis, made in this project, shows that there are feasible solutions for every tested case except at very high latitudes. Frequency planning, that is finding the less occupied channel, is almost as important as maximizing the signal to noise ratio. This project has been carried out on behalf of ÅF Technology in Solna, Sweden.

This thesis presents the design of a communication system (PRCS) which improves on all aspects of the current state of the art 4G communication system Long Term Evolution (LTE) including peak to average power ratio (PAPR), data reliability, spectral efficiency and complexity using the most recent state of the art research in the field combined with novel implementations. This research is relevant and important to the field of electrical and communication engineering because it provides benefits to consumers in the form of more reliable data with higher speeds as well as a reduced burden on hardware original equipment manufacturers (OEMs). The results presented herein show up to a 3 dB reduction in PAPR, less than 10-5 bit errors at 7.5 dB signal to noise ratio (SNR) using 4QAM, up to 3 times increased throughput in the uplink mode and 10 times reduced channel coding complexity.

A tecnologia de comunicação em redes sem fio em malha, com base no padrão IEEE 802.11, tem sido uma solução tecnológica relevante no cenário atual das redes sem fio. Entretanto, com a eliminação dos cabos para comunicação de dados, as redes sem fio em malha dependem de fonte de energia para energizar os pontos de acesso da rede, que nem sempre está disponível na forma cabeada no local da instalação. Neste cenário, sendo o Brasil um país situado em uma zona tropical com alta incidência anual de radiação solar, a possibilidade da utilização da conversão da energia solar em elétrica é uma alternativa para eliminar a dependência de fonte de energia cabeada dos pontos de acesso da rede sem fio em malha. Este trabalho apresenta considerações sobre o desenvolvimento de sistemas autônomos de comunicação sem fio em malha, alimentados por energia solar fotovoltaica, compactos e de fácil instalação em área urbana e rural. Apresenta também, informações sobre o protótipo implementado denominado SAM Solar e respectiva avaliação quanto a autonomia, área de cobertura, número de usuários, altura mínima de instalação e taxa de transferência. / The wireless mesh network communication technology, based on the IEEE802.11 standard, has been a relevant technology solution for wireless networking in the recent years. However, even with the elimination of cables for data communication, the wireless mesh networks have to be connected to a voltage source using an electrical cable that may not be available at the local installation. In this scenario, being Brazil a country located in a tropical zone that receives large annual solar irradiation, the conversion of photons to electricity an be an alternative to eliminate the needs of wiring to the mesh access points. This work contributes to the development of autonomous wireless mesh communication systems powered by solar energy, with easy installation in urban or rural areas. This work also describes its evaluations in aspects such as autonomy, wireless coverage, number of users supported, installation height and throughput.

A tecnologia de comunicação em redes sem fio em malha, com base no padrão IEEE 802.11, tem sido uma solução tecnológica relevante no cenário atual das redes sem fio. Entretanto, com a eliminação dos cabos para comunicação de dados, as redes sem fio em malha dependem de fonte de energia para energizar os pontos de acesso da rede, que nem sempre está disponível na forma cabeada no local da instalação. Neste cenário, sendo o Brasil um país situado em uma zona tropical com alta incidência anual de radiação solar, a possibilidade da utilização da conversão da energia solar em elétrica é uma alternativa para eliminar a dependência de fonte de energia cabeada dos pontos de acesso da rede sem fio em malha. Este trabalho apresenta considerações sobre o desenvolvimento de sistemas autônomos de comunicação sem fio em malha, alimentados por energia solar fotovoltaica, compactos e de fácil instalação em área urbana e rural. Apresenta também, informações sobre o protótipo implementado denominado SAM Solar e respectiva avaliação quanto a autonomia, área de cobertura, número de usuários, altura mínima de instalação e taxa de transferência. / The wireless mesh network communication technology, based on the IEEE802.11 standard, has been a relevant technology solution for wireless networking in the recent years. However, even with the elimination of cables for data communication, the wireless mesh networks have to be connected to a voltage source using an electrical cable that may not be available at the local installation. In this scenario, being Brazil a country located in a tropical zone that receives large annual solar irradiation, the conversion of photons to electricity an be an alternative to eliminate the needs of wiring to the mesh access points. This work contributes to the development of autonomous wireless mesh communication systems powered by solar energy, with easy installation in urban or rural areas. This work also describes its evaluations in aspects such as autonomy, wireless coverage, number of users supported, installation height and throughput.

Esta dissertação versa sobre a incomunicabilidade humana. A pergunta problematizadora que temos como objetivo aprofundar é: o ser humano é, ontologicamente, um ser capaz de se comunicar? ou de outra forma: é possível a existência da comunicação? A hermenêutica imanente dos textos de natureza filosófica, seguida da reflexão analítica, nos aproxima da problemática sobre a incomunicabilidade humana, iluminando os enfoques chave do estado instaurado de incomunicação radical e generalizada, por outro lado a possibilidade do ser de relacionar-se e abrir a comunicação para sua existência. A possibilidade do ser humano de relacionar-se é mínima no sistema planetário de comunicação, o que nos faz concluir que vivemos na era da incomunicabilidade humana, por primeiro da incomunicabilidade entre eu e o outro. / This dissertation deals with human incommunicability. We intend to further study the following problematizing issue: Ontologically speaking, is the human being capable of communicating? In other words: can communication exist? The immanent hermeneutics of philosophical texts, followed by analytical reflection, leads us to the problem of human incommunicability, throws light on key approaches to the state of radical and generalized incommunication, and, on the other hand, the possibility for human beings to establish relationships and open lines of communication for their survival. The planets communication system allows for minimal possibilities of human beings establishing relationships; we have, therefore, to conclude that we live in an era of human incommunicability, starting with the incommunicability between the self and others.

The purpose of the study was to evaluate the effectiveness of teaching a picture communication system to students with moderate to severe disabilities using the PECS Phase III application. A multiple probe across participants design was used to conduct the study and evaluate the effectiveness of the training on the PECS Phase III application. The results of the study demonstrated that teaching a picture communication system on an augmentative and alternative communication device is effective in the school setting with young adults with moderate and severe disabilities.

Novel event-triggered sensing and actuation strategies are presented for networked control systems with limited communication resources. Two architectures are considered: one with the controller co-located with the sensor and one with the control co-located with the actuator. A stochastic control problem with an optimal stopping rule is shown to capture two interesting instances of these architectures. The solution of the problem leads to a parametrization of the control alphabet as piecewise constant commands. The execution of the control commands is triggered by stopping rules for the sensor. In simple situations, it is possible to analytically derive the optimal controller. Examples illustrate how the new event-based control and sensing strategies outperform conventional time-triggered schemes. / <p>© 2008 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. Qc 20120220</p>

Syftet med denna studie var att undersöka hur en för situationen anpassad kommunikationskarta, en pratkarta, kan möjliggöra samtal mellan en 11-årig pojke med autism och utvecklingsstörning och hans mamma när de samtalar om en händelse som inte händer nu. Erik har inget fungerande tal och är beroende av Alternativ och Kompletterande Kommunikation (AKK). Han har sedan förskoletiden en pärm med löstagbara bilder (PECS), som han använder för att uttrycka sina behov och intentioner. I studien undersöktes hur interaktionen mellan Erik och hans mamma Maria organiserades sekventiellt. Analysen visade att en kommunikationskarta, en pratkarta med bilder anpassade för samtalet, var en viktig gemensam resurs för både Maria och Erik för att initiera, utveckla och avsluta pratstunden. Analysen baserades på videoinspelat material i hemmet, inspelat av Maria, där deltagarna pratade om den förestående julhelgen. Samtalsanalys (Conversation Analysis) användes som analysmetod. Det visade sig att deltagarna orienterar mot tre huvudsakliga faser i det kommunikativa projektet att etablera samtal om julen:prefas, huvudfas och postfas. Pratkartan var en viktig kommunikativ resurs för både Maria och Erik, vilken de orienterade mot i alla delar av samtalet. Prefasen bestod av de handlingar som leder fram till att Erik använder PECS-bilder för att involvera sig i samtalet. I prefasen var pratkartan helt avgörande för att Erik skulle komma igång och pecsa. I huvudfasen, den fas där Erik använder PECS-bilder för att samtala om julen, utvecklade Maria och Erik gemensamt olika ämnesaspekter av samtalet. Maria upprepade och utvidgade utifrån Eriks pecsyttranden. Hon gav också värderande bidrag och föreslog nya perspektiv på det pågående ämnet. Erik upprepade, byggde ut och överlappade Marias bidrag, men han kunde också aktivt bibehålla koherens i episoden och följde inte alltid Marias utvidgning eller förslag på nya ämnesaspekter. I postfasen avslutade deltagarna pratstunden och talet om julen. Erik bidrog aktivt till avslutandet genom att plocka ihop pratkartorna. Maria bekräftade både verbalt och genom att använda SLUTA-PRATA-bilden att pratstunden är avslutad. Förslag ges på framtida praktikbaserade studier som kan bidra till evidensbaserad praktik.

This thesis describes fundamental approaches to quantify rate versus power consumption tradeoffs for cascaded communication systems. The discussion is bolstered by a large number of in-situ channel measurements, which are used in discussions of the power consumption of future massively broadband cellular systems. Chapter one provides an introduction. Chapter two discusses power consumption trends in modern communication systems. Chapter three introduces the consumption factor framework. Chapter four discusses the channel measurement campaign. Chapter five concludes the thesis, and uses the measurement results to estimate power consumption and capacity of future cellular systems. In addition, chapter five extends the consumption factor theory and draws fundamental conclusions about the energy price per bit for a general cascaded communication system. / text

Three preschoolers with limited or no verbal language were taught to request preferred objects using an adapted Picture Exchange Communication System (Bondy & Frost, 1998) and elements of peer mediated instruction and intervention (Neitzel, 2008) (PECS/PMII). These two interventions have been established as evidence based practices, but have not previously been taught and implemented by one adult and a preschool child in a preschool classroom. Same-aged peers were the communicative partners for the picture exchange. A teacher served as the facilitator of the exchanges. A multiple probe (days) across participants design was utilized to determine the effectiveness of the intervention. The percentage of successful exchanges/requests made by the target child using the adapted PECS/PMII method was evaluated to determine the effectiveness of the intervention when implemented by a same-aged peer. The target children not only made requests to the criterion level, two of the three increased their appropriate verbal responses. The same-aged peers were able to effectively implement the steps for PECS phase 1.