No description available.

No description available.

No description available.

Many studies have been carried out throughout the world on how street-connected children relate to the streets, but not enough of these studies are seen through a gender perspective. Hence, the general conception of street-connected children is in some manner still mainstreamed, which casts an image claiming all children in the same category. This demonstrates that there is currently a missing gap of knowledge. This study covers whether the role of gender could affect the lives of the children that live and work on the streets, through a qualitative research in the field with 28 interviewees. These interviews were largely conducted in Brikama, Serekunda, Topkunda, Farafenni, Madina Salaam and Bakau in The Gambia, where the majority of the Gambian NGOs and street-connected children is located. The results from analysing these interviews pointed towards the same pattern: that there were a few similarities in the livelihoods of the street-connected boys and girls. However, the differences concerning their livelihoods on the streets were greater since the findings demonstrated that their challenges and opportunities of achieving the Ten Central Human Capabilities were different. Street-connected boys and street-connected girls were both exposed to child labour. The main difference was, street-connected boys, who lived in groups, worked in car garages, fish industries and for shop owners, while the few girls who permanently lived on the streets, were alone and sexual exploited. This research is thus not merely a contribution to the studies of street-connected children, but how gender is relating to the streets. Furthermore, a contribution to improve these vulnerable children’s livelihoods and also increase the awareness through the perspective of humanities, which might be crucial in future policy recommendations and research.

No description available.

The availability of high speed and high power switching devices, such as the IGBT, has opened the opportunity for an increasing number of grid-connected inverter applications that have historically been unachievable. Recently, the number of inverter applications has surged, with now the focus being on increasing the relative performance and power capability. Such applications include UPSs, dynamic voltage restorers, STATCOMs, frequency converters and distributed grid sources such as solar panels. The inverter switching frequency limits its associated bandwidth and hence performance. Every application can benefit by reduction of the extent of this limitation. While state of the art devices like IGBTs enable such applications, the onus is now on developing high bandwidth digital controllers; the ability to connect multiple devices together to achieve power scaling; and having the confidence that the applications will work with other systems on a grid.% Solutions for for improving the inverter performance, ability to scale the power and operation compliance with other grid-connected devices are sought. Constraints and limitations imposed by the hardware and traditional continuous-time derived controllers are identified. A discrete-time direct design controller is then developed specifically for digital controllers, that for the same inverter configuration, achieves twice the bandwidth of a well-tuned traditional controller. An important feature of a controller is having the configurability of being able to choose inverter bandwidth over stability margin. To provide power scaling above that of a single switching module, investigations are performed on the suitability of actively paralleling inverter modules. Both the use of the developed discrete direct design controller and the identification of potential inter-module instabilities for a particular configuration enables the application of paralleled inverters. The operation is confirmed through the application of a sixteen paralleled module inverter system. Finally, a graphical analysis technique is introduced for analysing complex grids that may include inverter systems. The graphical technique demonstrates stability constraints with a range of sources and loads, including both inverters and rotating machines, which historical analysis techniques have been unable to do.

Performance monitoring systems have experienced remarkable development in the past few decades. In today's world, an important issue for almost every industry is to find a way to appropriately evaluate the performance of the provided service. Having a reliable performance monitoring system is necessary, and researchers have developed assessment models and tools to deal with this concern. There are many approaches to the development of performance measurement and observation systems. The internet-of-things (IoT) creates a broad range of opportunities to monitor the systems by using the information from connected people and devices. The IoT is providing many new sources of data that need to be managed. One of the key issues that arises in any data management system is confidentiality and privacy.Significant progress has been made in development and deployment of performance monitoring systems in the signalized traffic environment. The current monitoring and data collection system relies mostly on infrastructure-based sensors, e.g. loop detectors, video surveillance, cell phone data, vehicle signatures, or radar. High installation and maintenance costs and a high rate of failure are the two major drawbacks of the existing system. Emerging technologies, i.e. connected vehicles (CV), will provide a new, high fidelity approach to be used for better performance monitoring and traffic control.This dissertation investigates the real-time performance observation system in a multi-modal connected vehicle environment. A trajectory awareness component receive and processes the connected vehicle data using the Basic Safety Message (BSM). A geo-fence section makes sure the infrastructure system (for example, roadside unit (RSU)) receives the BSM from only the connected vehicles on the roadway and within the communication range. The processed data can be used as an input to a real-time performance observer component.Three major classes of performance metrics, including mobility, signal, and CV-system measures, are investigated. Multi-modal dashboards that utilize radar diagrams are introduced to visualize large data sets in an easy to understand way. A mechanism to maintain the anonymity of vehicle information to ensure privacy was also developed. The proposed algorithm uses partial vehicle trajectories to estimate travel time average and variability on a link basis. It is shown that the model is not very sensitive to the market penetration rate of connected vehicles. This is a desirable feature especially because of the fact that the market penetration rate of connected vehicles will not be very high in near future. The system architecture for connected vehicle based performance observation applications was developed to be applicable for both a simulation environment and a real world traffic system. Both hardware-in-the-loop (HIL) and software-in-the-loop (SIL) simulation environments are developed and calibrated to mimic the real world. Comprehensive testing and assessment of the proposed models and algorithms are conducted in simulation as well as field test networks. A web application is also developed as part of a central system component to generate reports and visualizations of the data collection experiments.

Master of Science / Department of Architectural Engineering and Construction Science / Fred L. Hasler / The Internet of Things (IoT) is rapidly growing and is starting to be incorporated into commercial buildings. One of the ways that the IoT is being used in buildings is connected lighting, also referred to as smart lighting. Connected lighting allows for communication between the lighting system, people, the environment, and other devices. This paper will focus on connected lighting and its effect on lighting controls and design. The IoT is expected to see substantial growth in the next few years and the growth of connected devices will have a huge impact on the lighting industry as connected lighting systems will be installed in more commercial buildings. The shift to solid state lighting (SSL) in recent years has brought the transition from conventional lighting controls to connected lighting controls. For this shift to be successful, issues with interoperability, security and reliability will need to be overcome. Connected lighting systems on the market are using both wired and wireless technologies. Power over Ethernet (PoE) and wireless technologies such as ZigBee and Bluetooth Smart are currently being incorporated into connected lighting systems. The introduction of these technologies is changing the way that lighting control systems are designed and installed. Products such as fixture-integrated sensors and wireless devices are also being used in connected lighting systems. These products, along with the wired and wireless technologies, are changing lighting control system configurations. Lighting design will also be affected by connected lighting systems. New features including color-tunability and indoor positioning will be used to enhance the lighting system and improve occupant health. Also, energy code compliance will be easier since connected lighting controls will be mostly software-based and can be reprogrammed. Connected lighting systems will be integrated into other building systems such as heating, ventilating, and air conditioning systems or security systems and will also be used in a variety of applications. Connected lighting systems will greatly affect both lighting controls and design of lighting control systems. This paper introduces connected lighting and is intended for those who are not familiar with its design, applications, and implementation.

Este trabalho apresenta o desenvolvimento de uma metodologia para a etiquetagem e qualificação de inversores para Sistemas Fotovoltaicos Conectados à Rede, com finalidade de servir de proposta de procedimento para inclusão no Regulamento de Avaliação de Conformidade de Equipamentos e Sistemas Fotovoltaicos do Programa Brasileiro de Etiquetagem. O procedimento desenvolvido avalia os inversores quanto à eficiência, qualidade de energia, proteções e informações operacionais e de instalação. / This work presents the development of a methodology for qualification and labeling of inverters for grid-connected photovoltaic systems, aiming serving as procedural proposal for inclusion in the Conformity Assessment Rules of Equipments and Photovoltaic Systems of the Brazilian Labeling Program. The developed procedure evaluates the inverters efficiency, power quality, protections and operational and installation information.

Reaction-diffusion systems and delay differential equations have been extensively used over the years to model and study the dynamics of infectious diseases. In this thesis we consider two aspects of disease dynamics: spatial dynamics in a reaction-diffusion epidemic model with nonlinear incidence rate, and a delayed epidemic model with combined effects of latency and temporary immunity. The first part of the thesis is devoted to the analysis of stability and pattern formation in an SIS-type epidemic model with nonlinear incidence rate. By considering the dynamics without spatial component, conditions for local asymptotic stability are obtained for general values of the powers of nonlinearity. We prove positivity, boundedness, invariant principle and permanence of our model. The next generation matrix method is used to derive the corresponding basic reproductive number R0, and the Routh-Hurwitz criterion is used to show that for R0 ≤ 1, the disease-free equilibrium is found to be locally asymptotically stable, for R0 > 1, a unique endemic steady state exists and is found to be locally asymptotically stable. In the presence of diffusion, Turing instability conditions are established in terms of system parameters. Numerical simulations are performed to identify the spatial regions for spots, stripes and labyrinthine patterns in the parameter space. Numerical simulations show that the system has complex and rich dynamics and can exhibit complex patterns, depending on the recovery rate r and the transmission rate β. We have discovered that whenever the transmission rate exceeds the recovery rate the system exhibits stripe patterns which correspond to a disease outbreak, and in the opposite case the system settles on spot patterns which imply the absence of disease outbreaks. Also, we find that increasing the power q can lead to epidemic outbreak even at lower values of the transmission rate β. All numerical simulations use an Implicit-Explicit (IMEX) Euler's method, which computes diffusion terms in Fourier space and reaction terms in the real space. Numerical approximation of the model is benchmarked to prove stability of the numerical scheme, and the method is shown to converge with the correct order. Experimental order of convergence (EOC) and estimates for the error in both L2, H1 and maximum norms have also been computed. Also, we compare our results to those on infectious diseases and our model shows good predictions. In the second part of this thesis, we derive and analyse a delayed SIR model with bilinear incidence rate and two time delays which represent latency Τ1 and temporary immunity Τ2 periods. We prove both local and global stability of the system equilibria in the case when there are no time delays, i.e. both the latency and temporary immunity periods are set to zero. For the case when there is only latency (Τ1 > 1, Τ2 = 0) and the case when the two time delays are identical (Τ1 = Τ2 = Τ ), we show that the endemic steady state is always stable for any parameter values. For the case when there is only temporary immunity (Τ2 > 0, Τ1 = 0) and the case when there are both latency and temporary immunity in the system (Τ1 > 0, Τ2 > 0), we prove the existence of periodic solutions arising from the Hopf bifurcation. The endemic steady state undergoes Hopf bifurcation giving rise to stable periodic solutions. For the last two cases, we show interesting regions of (in)stability of the endemic steady state in the different parameter regimes. We find that by varying the transmission rate β, the natural death rate γ and the disease-induced death rate μ increase the regions of (in)stability. Also, we find that the dynamics of the system is richer when we have the two time delays in the model. Analytical results are supported by extensive numerical simulations, illustrating temporal behaviour of the system in different dynamical regimes. Finally, we relate our results to modelling infectious diseases and our results show good predictions of safety and epidemic outbreak.