COMPRESSIVE QUANTIZATION FOR SCALABLE CLOUD RADIO ACCESS NETWORKS

With the proliferation of new mobile devices and applications, the demand for ubiquitous wireless services has increased dramatically in recent years. The explosive growth in the wireless traffic requires the wireless networks to be scalable so that they can be efficiently extended to meet the wireless communication demands. In a wireless network, the interference power typically grows with the number of devices without necessary coordination among them. On the other hand, large scale coordination is always difficult due to the low-bandwidth and high-latency interfaces between access points (APs) in traditional wireless networks. To address this challenge, cloud radio access network (C-RAN) has been proposed, where a pool of base band units (BBUs) are connected to the distributed remote radio heads (RRHs) via high bandwidth and low latency links (i.e., the front-haul) and are responsible for all the baseband processing. But the insufficient front-haul link capacity may limit the scale of C-RAN and prevent it from fully utilizing the benefits made possible by the centralized baseband processing. As a result, the front-haul link capacity becomes a bottleneck in the scalability of C-RAN. In this dissertation, we explore the scalable C-RAN in the effort of tackling this challenge. In the first aspect of this dissertation, we investigate the scalability issues in the existing wireless networks and propose a novel time-reversal (TR) based scalable wireless network in which the interference power is naturally mitigated by the focusing effects of TR communications without coordination among APs or terminal devices (TDs). Due to this nice feature, it is shown that the system can be easily extended to serve more TDs. Motivated by the nice properties of TR communications in providing scalable wireless networking solutions, in the second aspect of this dissertation, we apply the TR based communications to the C-RAN and discover the TR tunneling effects which alleviate the traffic load in the front-haul links caused by the increment of TDs. We further design waveforming schemes to optimize the downlink and uplink transmissions in the TR based C-RAN, which are shown to improve the downlink and uplink transmission accuracies. Consequently, the traffic load in the front-haul links is further alleviated by the reducing re-transmissions caused by transmission errors. Moreover, inspired by the TR-based C-RAN, we propose the compressive quantization scheme which applies to the uplink of multi-antenna C-RAN so that more antennas can be utilized with the limited front-haul capacity, which provide rich spatial diversity such that the massive TDs can be served more efficiently.

Phase transitions in gene networks evolved under different selection rules

Mathematical models of gene regulation are a powerful tool for understanding the complex features of genetic control. While various modeling efforts have been successful at explaining gene expression dynamics, much less is known about how evolution shapes the structure of these networks. An important feature of gene regulatory networks is their stability in response to environmental perturbations. Regulatory systems are thought to have evolved to exist near the transition between stability and instability, in order to have the required stability to environmental fluctuations while also being able to achieve a wide variety of functions (corresponding to different dynamical patterns). We study a simplified model of gene network evolution in which links are added via different selection rules. These growth models are inspired by recent work on `explosive' percolation which shows that when network links are added through competitive rather than random processes, the connectivity phase transition can be significantly delayed, and when it is reached, it appears to be first order (discontinuous, e.g., going from no failure at all to large expected failure) instead of second order (continuous, e.g., going from no failure at all to very small expected failure). We find that by modifying the traditional framework for networks grown via competitive link addition to capture how gene networks evolve to avoid damage propagation, we also see significant delays in the transition that depend on the selection rules, but the transitions always appear continuous rather than `explosive'.

A monitorização da carga de treino através da análise tempo-movimento e da perceção subjetiva do esforço, PSE, no futebol

O objetivo do presente estudo foi verificar se existe variação dos parâmetros que caraterizam a atividade motora de jogadores de futebol em treino, obtidos através do Viper Software STATSports, ao longo de vários microciclos (MCs) integrando o período preparatório (PP) e o início do período competitivo (PC), assim como, averiguar a associação existente entre a variação destes parâmetros, MC a MC, e a Perceção Subjetiva do Esforço Sessão (PSE-sessão) respetiva, e verificar, ainda, se existe correlação entre estes parâmetros e a PSE, em cada MC do período considerado. A amostra do estudo foi constituída por 13 jogadores (idade: 25 ± 1,78 anos) de futebol do sexo masculino a competir no escalão de Séniores da Associação Futebol de Setúbal. A recolha de dados ocorreu durante o PP (4 semanas) e o PC (4 semanas). Os jogadores incluídos no estudo cumpriram o único critério definido: a realização total das sessões de treino previstas. Os instrumentos utilizados durante o processo foram o sistema Viper (Viper Software v.1.2, STATSports), integrando um GPS 10 Hz, acelerómetro 100 Hz, cardiofrequencímetro e a escala de PSE adaptada por Foster. Verificou-se elevada variabilidade no comportamento dos parâmetros no PP, mas não nos 3 últimos MCs já integrados no PC. Verificamos forte associação entre os parâmetros Distância Explosiva (r=0,762), Nº Esforços de Elevada Carga Metabólica (r=0,714), Nº Acelerações (r=0,714), Nº Desacelerações (r=0,762) e a PSE-sessão (p˂0,05). O parâmetro com maior potencial preditor de elevados valores da PSE-sessão é a Distância Explosiva (p˂0,001). Por fim, não encontramos uma associação regular entre os parâmetros e a PSE-sessão em cada MC. Os valores de PSE-sessão apresentados durante o estudo são semelhantes a valores apresentados em outros estudos no futebol profissional. Conclui-se que no PP ocorreu a variabilidade de todos os parâmetros e estabilização no PC da Distância Total, Distância de Elevada Carga Metabólica, Distâcia Explosiva, Nº Esforços de Elevada Carga Metabólica e PSE-sessão. A PSE-sessão depende dos parâmetros Distância Explosiva, Nº Esforços de Elevada Carga Metabólica, Nº Acelerações e Nº Desacelerações, i.e., as ações de elevada exigência metabólica e neuromuscular explicam a relação existente entre os parâmetros de carga e a PSE-sessão como indicador global de carga interna. A utilização do sistema Viper possibilita a recolha de parâmetros que descrevem as exigências fisícas a que os jogadores estão sujeitos e fornece informação fundamental para o planeamento do treino em conjunto com a recolha sistemática da PSE-sessão.

A Simulação nos Desafios do Futuro para a Operacionalidade das Forças de Segurança: o seu Emprego na Guarda Nacional Republicana

O objetivo da simulação é confrontar os instruendos com situações que permitam recriar as condições mais próximas da realidade, para que o processo de aprendizagem possa atingir os objetivos da formação. As polícias estrangeiras já utilizam simuladores nas áreas do ensino da condução, tiro, inativação de engenhos explosivos e fiscalização rodoviária. Cada equipamento ensina e desenvolve as capacidades dos agentes policiais, que por sua vez, contribui para a promoção da eficácia policial. Este estudo estabelece a ligação entre os conceitos de simulação e de formação no sentido de tentar desenvolver as linhas orientadoras da formação policial da GNR com recurso à simulação. Abstract: The intent of simulations is to immerse trainees in situations wich provide to recreate conditions similar to reality, for the purpose that the training process would reach training objectives. Law enforcement agencies abroad already use simulators for driver training, shooting, explosive ordinance disposal and road and transport enforcement. Each equipment teaches and enhance skills of individual officers which, in turn, will contribute to promote police effectiveness. This study aims to link the concepts of simulation and training in order to develop the guidelines of the GNR police training using simulators.

Plantar a cidade

Dissertação para obtenção do grau de Mestre em Arquitectura, apresentada na Universidade de Lisboa - Faculdade de Arquitetura.

A contrainsurgência na atualidade : Ambiente OTAN

O presente trabalho de investigação versa sobre o tema “A contrainsurgência na atualidade: ambiente Organização do Tratado Atlântico Norte”. O objetivo desta investigação será identificar quais os aspetos a melhorar na organização, no aprontamento e nos meios necessários para uma Quick Reaction Force enfrentar um adversário insurgente num teatro de operações de uma força da Organização do Tratado Atlântico Norte. Pretende-se analisar o emprego das Forças Comandos integrando os módulos do Apoio de Combate e Apoio de Serviços. Assim, esta investigação iniciar-se-á com uma componente teórica, fundamentada numa pesquisa bibliográfica, seguida de uma componente prática, correspondente à realização de entrevistas que permitiram obter respostas para a questão central em apreço. Estas duas componentes culminam com a conclusão resultante do processo de investigação. O presente trabalho de investigação aplicada permitiu concluir que, relativamente à organização, a força de Comandos, integrada com os seus módulos provou ser a adequada para o cumprimento da missão de Quick Reaction Force, denotando, ainda assim, carência relativamente à inclusão de equipas de desativação de engenhos explosivos. O treino da força provou ser o adequado, estando relacionado com o tipo de tarefas que efetivamente foram realizadas no Afeganistão. Nos meios que equipavam a força, apesar de adequados, constatou-se que seria necessária uma atualização relativamente às versões dos mesmos.

SLOPE STABILITY ANALYSIS OF MOUNT MEAGER, SOUTH-WESTERN BRITISH COLUMBIA, CANADA

The Mount Meager Volcanic Complex (MMVC) in south-western British Columbia is a potentially active, hydrothermally altered massif comprising a series of steep, glaciated peaks. Climatic conditions and glacial retreat has led to the further weathering, exposure and de-buttressing of steep slopes composed of weak, unconsolidated material. This has resulted in an increased frequency of landslide events over the past few decades, many of which have dammed the rivers bordering the Complex. The breach of these debris dams presents a risk of flooding to the downstream communities. Preliminary mapping showed there are numerous sites around the Complex where future failure could occur. Some of these areas are currently undergoing progressive slope movement and display features to support this such as anti-scarps and tension cracks. The effect of water infiltration on stability was modelled using the Rocscience program Slide 6.0. The main site of focus was Mount Meager in the south- east of the Complex where the most recent landslide took place. Two profiles through Mount Meager were analysed along with one other location in the northern section of the MMVC, where instability had been detected. The lowest Factor of Safety (FOS) for each profile was displayed and an estimate of the volume which could be generated was deduced. A hazard map showing the inundation zones for various volumes of debris flows was created from simulations using LAHARZ. Results showed the massif is unstable, even before infiltration. Varying the amount of infiltration appears to have no significant impact on the FOS annually implying that small changes of any kind could also trigger failure. Further modelling could be done to assess the impact of infiltration over shorter time scales. The Slide models show the volume of material that could be delivered to the Lillooet River Valley to be of the order of 109 m3 which, based on the LAHARZ simulations, would completely inundate the valley and communities downstream. A major hazard of this is that the removal of such a large amount of material has the potential to trigger an explosive eruption of the geothermal system and renew volcanic activity. Although events of this size are infrequent, there is a significant risk to the communities downstream of the complex.

CHARACTERIZING THE FIRST HISTORIC ERUPTION OF NABRO, ERITREA: INSIGHTS FROM THERMAL AND UV REMOTE SENSING

June 2011 saw the first historic eruption of Nabro volcano, one of an ongoing sequence of eruptions in the Afar-Red Sea region since 2005. It halted air travel in northern Africa, contaminated food and water sources, and displaced thousands from their homes. Due to its remote location, little was known about this event in terms of the quantity of erupted products and the timing and mechanisms of their emplacement. Geographic isolation, previous quiescence and regional civil unrest meant that this volcano was effectively unmonitored at the time of eruption, and opportunities for field study are limited. Using free, publicly available satellite data, I examined rates of lava effusion and SO2 emission in order to quantify the amount of erupted products and understand the temporal evolution of the eruption, as well as explore what information can be gleaned about eruption mechanisms using remote sensing data. These data revealed a bimodal eruption, beginning with explosive activity marked by high SO2 emission totalling 1824 - 2299 KT, and extensive ash fall of 270 - 440 km2. This gave way to a period of rapid effusion, producing a ~17 km long lava flow, and a volume of ~22.1 x 106 m3. Mass balance between the SO2 and lava flows reveals no sulfur 'excess', suggesting that nearly all of the degassed magma was extruded. The 2011 eruption of Nabro lasted nearly 6 weeks, and may be considered the second largest historic eruption in Africa. Work such as this highlights the importance of satellite remote sensing for studying and monitoring volcanoes, particularly those in remote regions that may be otherwise inaccessible.

Volcanic processes and human exposure as elements to build a risk model for Volcan de Fuego, Guatemala

The activity of Fuego volcano during the 1999 - 2013 eruptive episode is studied through field, remote sensing and observatory records. Mapping of the deposits allows quantifying the erupted volumes and areas affected by the largest eruptions during this period. A wide range of volcanic processes results in a diversity of products and associated deposits, including minor airfall tephra, rockfall avalanches, lava flows, and pyroclastic flows. The activity can be characterized by long term, low level background activity, and sporadic larger explosive eruptions. Although the background activity erupts lava and ash at a low rate (~ 0.1 m3/s), the persistence of such activity over time results in a significant contribution (~ 30%) to the eruption budget during the studied period. Larger eruptions produced the majority of the volume of products during the studied period, mainly during three large events (May 21, 1999, June 29, 2003, and September 13, 2012), mostly in the form of pyroclastic flows. A total volume of ~ 1.4 x 108 m3 was estimated from the mapped deposits and the estimated background eruption rate. Posterior remobilization of pyroclastic flow material by stream erosion in the highly confined Barranca channels leads to lahar generation, either by normal rainfall, or by extreme rainfall events. A reassessment of the types of products and volumes erupted during the decade of 1970's allows comparing the activity happening since 1999 with the older activity, and suggests that many of the eruptive phenomena at Fuego may have similar mechanisms, despite the differences in scale between. The deposits of large pyroclastic flows erupted during the 1970's are remarkably similar in appearance to the deposit of pyroclastic flows from the 1999 - 2013 period, despite their much larger volume; this is also the case for prehistoric eruptions. Radiocarbon dating of pyroclastic flow deposits suggests that Fuego has produced large eruptions many times during the last ~ 2 ka, including larger eruptions during the last 500 years, which has important hazard implications. A survey was conducted among the local residents living near to the volcano, about their expectations of possible future crises. The results show that people are aware of the risk they could face in case of a large eruption, and therefore they are willing to evacuate in such case. However, their decision to evacuate may also be influenced by the conditions in which the evacuation could take place. If the evacuation represents a potential loss of their livelihood or property they will be more hesitant to leave their villages during a large eruption. The prospect of facing hardship conditions during the evacuation and in the shelters may further cause reluctance to evacuate. A short discussion on some of the issues regarding risk assessment and management through an early warning system is presented in the last chapter.

The Development of Calibrants through Characterization of Volatile Organic Compounds from Peroxide Based Explosives and a Non-target Chemical Calibration Compound

Detection canines represent the fastest and most versatile means of illicit material detection. This research endeavor in its most simplistic form is the improvement of detection canines through training, training aids, and calibration. This study focuses on developing a universal calibration compound for which all detection canines, regardless of detection substance, can be tested daily to ensure that they are working with acceptable parameters. Surrogate continuation aids (SCAs) were developed for peroxide based explosives along with the validation of the SCAs already developed within the International Forensic Research Institute (IFRI) prototype surrogate explosives kit. Storage parameters of the SCAs were evaluated to give recommendations to the detection canine community on the best possible training aid storage solution that minimizes the likelihood of contamination. Two commonly used and accepted detection canine imprinting methods were also evaluated for the speed in which the canine is trained and their reliability. As a result of the completion of this study, SCAs have been developed for explosive detection canine use covering: peroxide based explosives, TNT based explosives, nitroglycerin based explosives, tagged explosives, plasticized explosives, and smokeless powders. Through the use of these surrogate continuation aids a more uniform and reliable system of training can be implemented in the field than is currently used today. By examining the storage parameters of the SCAs, an ideal storage system has been developed using three levels of containment for the reduction of possible contamination. The developed calibration compound will ease the growing concerns over the legality and reliability of detection canine use by detailing the daily working parameters of the canine, allowing for Daubert rules of evidence admissibility to be applied. Through canine field testing, it has been shown that the IFRI SCAs outperform other commercially available training aids on the market. Additionally, of the imprinting methods tested, no difference was found in the speed in which the canines are trained or their reliability to detect illicit materials. Therefore, if the recommendations discovered in this study are followed, the detection canine community will greatly benefit through the use of scientifically validated training techniques and training aids.

Determining magmatic processes from analysis of phenocrysts and gabbroic xenoliths contained in Calbuco andesites

Calbuco Volcano, in Southern Chile, has eruptive products of predominantly andesitic hornblende-bearing lava. A purpose of this work is to understand magmatic processes and how Calbuco magma chemistry is related to the explosive volcanic character. Calbuco lava has a mineral assemblage of plagioclase, hornblende, orthopyroxene, clinopyroxene, olivine, and magnetite and entrained gabbroic xenoliths with the same mineral assemblage. The presence of hornblende is evidence for dissolved water in the magma. Detailed petrographic/textural analysis has been done using petrographic microscopy and back-scattered electron imaging (BSE); geochemical analysis by electron microprobe (EPMA). Major findings include 1) that hornblende and hornblende-bearing gabbroic cumulates crystallize from Calbuco magma, 2) that plagioclase grains are compositionally zoned, recording evidence of temperature, chemical, and water content fluctuations in the magma, and 3) that hornblende is unstable under upper magma chamber conditions at Calbuco, and is breaking down into plagioclase, olivine, orthopyroxene, clinopyroxene, and magnetite in the magma.

Fuel level sensor based on polymer optical fiber Bragg gratings for aircraft applications

Safety in civil aviation is increasingly important due to the increase in flight routes and their more challenging nature. Like other important systems in aircraft, fuel level monitoring is always a technical challenge. The most frequently used level sensors in aircraft fuel systems are based on capacitive, ultrasonic and electric techniques, however they suffer from intrinsic safety concerns in explosive environments combined with issues relating to reliability and maintainability. In the last few years, optical fiber liquid level sensors (OFLLSs) have been reported to be safe and reliable and present many advantages for aircraft fuel measurement. Different OFLLSs have been developed, such as the pressure type, float type, optical radar type, TIR type and side-leaking type. Amongst these, many types of OFLLSs based on fiber gratings have been demonstrated. However, these sensors have not been commercialized because they exhibit some drawbacks: low sensitivity, limited range, long-term instability, or limited resolution. In addition, any sensors that involve direct interaction of the optical field with the fuel (either by launching light into the fuel tank or via the evanescent field of a fiber-guided mode) must be able to cope with the potential build up of contamination-often bacterial-on the optical surface. In this paper, a fuel level sensor based on microstructured polymer optical fiber Bragg gratings (mPOFBGs), including poly (methyl methacrylate) (PMMA) and TOPAS fibers, embedded in diaphragms is investigated in detail. The mPOFBGs are embedded in two different types of diaphragms and their performance is investigated with aviation fuel for the first time, in contrast to our previous works, where water was used. Our new system exhibits a high performance when compared with other previously published in the literature, making it a potentially useful tool for aircraft fuel monitoring.

Developmental and physical-fitness associations with gross motor coordination problems in peruvian children

he aims of this cross-sectional study were to examine the developmental characteristics (biological maturation and body size) associated with gross motor coordination problems in 5193 Peruvian children (2787 girls) aged 6–14 years from different geographical locations, and to investigate how the probability that children suffer with gross motor coordination problems varies with physical fitness. Children with gross motor coordination problems were more likely to have lower flexibility and explosive strength levels, having adjusted for age, sex, maturation and study site. Older children were more likely to suffer from gross motor coordination problems, as were those with greater body mass index. However, more mature children were less likely to have gross motor coordination problems, although children who live at sea level or at high altitude were more likely to suffer from gross motor coordination problems than children living in the jungle. Our results provide evidence that children and adolescents with lower physical fitness are more likely to have gross motor coordination difficulties. The identification of youths with gross motor coordination problems and providing them with effective intervention programs is an important priority in order to overcome such developmental problems, and help to improve their general health status.

A influência de um protocolo de treino pliométrico na força explosiva em jovens atletas de voleibol feminino

Projeto de Graduação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Licenciado em Fisioterapia

Comparación entre los efectos de un programa de entrenamiento de fuerza explosiva mediante bandas elásticas y un programa de entrenamiento con electro-estimulación de cuerpo completo

El objetivo del presente estudio fue analizar los cambios en el rendimiento en función de dos métodos de entrenamiento, el desarrollado mediante electro-estimulación muscular integral (EMI) frente a otro en el que se utilizaron bandas elásticas y que denominamos entrenamiento funcional con elásticos (EFE). La muestra estuvo compuesta por un grupo de diez (N=10) personas físicamente activas (23,04 ± 2,5 años). Se utilizó un diseño cuasi-experimental con medidas pre-post. Y fueron analizados los resultados de las pruebas: salto vertical con ayuda de brazos; y velocidad de desplazamiento en una carrera de ida y vuelta de 12 metros de distancia (6+6). Se realizó un análisis descriptivo de casos y medias. Y dado el tamaño de la muestra se calculó el tamaño del efecto, el cual fue bajo o moderado (d<0,5). Por último se compararon las diferencias de las medias de los grupos mediante la U de Mann Whitney, y las diferencias de las medias en función del tiempo (pre-post) mediante Friedman; en ambos casos los resultados no fueron significativos (p<0,5). En cuanto a los valores descriptivos del pre-post en ambos grupos: el grupo que entrenó con bandas elásticas obtuvo mejores resultados en ambas pruebas que el grupo que entrenó con EMI. En conclusión, el entrenamiento con bandas elásticas, a pesar de no ser significativo, parece mostrarse más efectivo que el entrenamiento con electro-estimulación muscular integral. Si bien, dadas las limitaciones del estudio estos datos hay que tomarlos con la pertinente cautela.