Link Adaptation for WiMAX Supported Mobile Hotspot

In recent years, mobile hotspots have been getting much attention of the researchers. They are implemented on moving platforms. Research interests in mobile hotspots are motivated by the demand of seamless mobility. The IEEE 802.16e or mobile WiMAX opens a new door of possibility of mobile broadband. It provides extended mobility support and larger cell coverage. In this thesis we propose a simple link adaptation (LA) algorithm for the mobile hotspots, which are supported by (mobile) WiMAX network. The role of link adaptation (LA) is very important because it controls the physical layer throughput. Therefore, all the higher layers are affected by LA. The main function of an LA algorithm is to select an appropriate burst profile. We consider downlink scenarios of WiMAX supported mobile hotspot. We formulate a discrete value optimization problem for LA, whose objective is throughput maximization. We choose forward error correction block rate (FBER) as constraint. The proposed LA algorithm comes as solution of the optimization problem. The proposed algorithm adapt with MAC layer performance. We develop a downlink channel estimation technique, propose an intra subchannel power allocation strategy, and propose an adaptive automatic repeat request (ARQ) mechanism as part of LA technique. We estimate SNR using channel estimation and intra subchannel power allocation. Then the estimated SNR is adjusted based on velocity of mobile hotspot. Adjusted SNR is used to select optimum burst profile. The performances of the proposed LA algorithm are evaluated through numerical results obtained from link level simulations. According to numerical results, the proposed LA algorithm is able to maintain a certain level quality of service (QoS)

Advancing Urban Flood Resilience With Smart Water Infrastructure

Advances in wireless communications and low-power electronics are enabling a new generation of smart water systems that will employ real-time sensing and control to solve our most pressing water challenges. In a future characterized by these systems, networks of sensors will detect and communicate flood events at the neighborhood scale to improve disaster response. Meanwhile, wirelessly-controlled valves and pumps will coordinate reservoir releases to halt combined sewer overflows and restore water quality in urban streams. While these technologies promise to transform the field of water resources engineering, considerable knowledge gaps remain with regards to how smart water systems should be designed and operated. This dissertation presents foundational work towards building the smart water systems of the future, with a particular focus on applications to urban flooding. First, I introduce a first-of-its-kind embedded platform for real-time sensing and control of stormwater systems that will enable emergency managers to detect and respond to urban flood events in real-time. Next, I introduce new methods for hydrologic data assimilation that will enable real-time geolocation of floods and water quality hazards. Finally, I present theoretical contributions to the problem of controller placement in hydraulic networks that will help guide the design of future decentralized flood control systems. Taken together, these contributions pave the way for adaptive stormwater infrastructure that will mitigate the impacts of urban flooding through real-time response.PHDCivil EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/163144/1/mdbartos_1.pd

Cycling risks communication using Web-GIS: different visualisation techniques and their effectiveness

Scottish Government has been committed for many years to encouraging cycling as main private means of transport, in 2008 1% of all Scottish travel were made by bicycle, the vision is to increase this rate to 10% by 2020. In 2012, 2% of travels between 3 and 5 km in Scotland were made by bicycle, the goal is actually far but in the meantime we are noticing that cycling has become more and more popular in daily commute, especially in urban environments where its rapid growth has usually been associated with safety problems. In Scotland and UK between 2011 and 2012 the number of people injured in accidents involving bicycles has raised. Reducing casualties is therefore a primary objective sought by public institutions at any levels. I will explore innovative visualisation techniques and I will elaborate a safe route planner able avoid critical areas where cycling accidents tend to cluster. Bicycles collisions data from 2005-2012 are provided by Department for Transport. A safe route choice model will make use of information derived from this dataset to optimise a least cost path algorithm for the route planner. Effectiveness of the route planner will be tested to assess the risk reduction and to evaluate how conceived risk communication techniques succeed at generating awareness in experienced and non-experienced cyclists. The first test will actually highlight the success of the model while users will responses will vary according to their cycling experience. The research will fill gaps regarding cyclist aimed web-GIS services and at the same time will point out how the communication and perception of risk might be taken into account for further research

Dynamize CERES: Bringing Activities to a Community Environment Park

CERES Community Environment Park in Melbourne is a leader in environmental practice in Australia, but it offers no interactive activities for visitors. In order to add fun family activities to the park, we conducted surveys on visitors, interviews with CERES employees and local experts, observations of park visitors, and playtesting of our activities. Our final deliverables included seven activities based in the CERES Chook app, data on high-traffic park areas, and recommendations for improving both the app and the park as a whole

Delay-Aware Online Service Scheduling in High-Speed Railway Communication Systems

We investigate the downlink service scheduling problem in relay-assisted high-speed railway (HSR) communication systems, taking into account stochastic packet arrivals and quality-of-service (QoS) requirements. The scheduling problem is formulated as an infinite-horizon average cost constrained Markov decision process (MDP), where the scheduling actions depend on the channel state information (CSI) and the queue state information (QSI). Our objective is to find a policy that minimizes the average end-to-end delay through scheduling actions under the service delivery ratio constraints. To address the challenge of centralized control and high complexity of traditional MDP approaches, we propose a distributed online scheduling algorithm based on approximate MDP and stochastic learning, where the scheduling policy is a function of the local CSI and QSI only. Numerical experiments are carried out to show the performance of the proposed algorithm

Information collection algorithm for vehicular ad-hoc networks (application domain: Urban Traffic Wireless Vehicular Ad-Hoc Networks (VANETs))

Vehicle to vehicle communication (V2VC) is one of the modern approaches for exchanging and generating traffic information with (yet to be realized) potential to improve road safety, driving comfort and traffic control. In this research, we present a novel algorithm which is based on V2V communication, uses in-vehicle sensor information and in collaboration with the other vehicles' sensor information can detect road conditions and determine the geographical area where this road condition exists – e.g. geographical area where there is traffic density, unusual traffic behaviour, a range of weather conditions (raining), etc. The algorithms' built-in automatic geographical restriction of the data collection, aggregation and dissemination mechanisms allows warning messages to be received by any car, not necessarily sharing the identified road condition, which may then be used to identify the optimum route taken by the vehicle e.g. avoid bottlenecks or dangerous areas including accidents or congestions on their current routes. This research covers the middle ground between MANET [1] and collaborative data generation based on knowledge granularity (aggregation). It investigates the possibility of designing, implementing and modelling of the functionality of an algorithm (as part of the design of an intelligent node in an Intelligent Transportation System - ITS) that ensures active participation in the formation, routing and general network support of MANETs and also helps in-car traffic information and real-time control generation and distribution. The work is natural extension of the efforts of several large EU projects like DRIVE [2], GST [3] and SAFESPOT [4]

Analysis and optimization of resource control in high-speed railway wireless networks

This paper considers a joint optimal design of admission control and resource allocation for multimedia services delivery in highspeed railway (HSR) wireless networks. A stochastic network optimization problem is formulated which aims at maximizing the system utility while stabilizing all transmission queues under the average power constraint. By introducing virtual queues, the original problem is equivalently transformed into a queue stability problem, which can be naturally decomposed into three separate subproblems: utility maximization, admission control, and resource allocation. A threshold-based admission control strategy is proposed for the admission control subproblem. And a distributed resource allocation scheme is developed for the mixed-integer resource allocation subproblem with guaranteed global optimality. Then a dynamic admission control and resource allocation algorithm is proposed, which is suitable for distributed implementation. Finally, the performance of the proposed algorithm is evaluated by theoretical analysis and numerical simulations under realistic conditions of HSR wireless networks

A mobile tour guide app for sustainable tourism

Portugal has had a flourishing tourism sector for the past few years. In fact, Portugal’s tourism boom has made the industry one of the biggest contributors to the national economy and the largest employer. In the year 2019, Portugal had a total of 27 million tourists, surpassing once again the record established in the previous year. However, tourism also brings a series of unintended negative side effects, such as overcrowding. The Santa Maria Maior historic district in Lisbon is being particularly affected by this problem. The work undertaken in this dissertation is part of the Sustainable Tourism Crowding project, that aims to mitigate the overcrowding phenomenon in this district, by fostering a balanced distribution of visitors while promoting the visitation of sustainable points of interest. This dissertation focuses on developing a mobile app prototype targeted at tourists, through which these sustainable walking tour recommendations can be delivered. To validate the functional requirements of the prototype, more specifically the trip creation process, a series of unit tests, integration tests, and manual tests were developed. To evaluate the usability of the prototype, a user-centered approach was adopted during the design stage, in which two usability techniques were conducted with members of ISCTE’s research center ISTAR and partners from the Junta de Freguesia de Santa Maria Maior, that guided and validated the decisions made. The achieved prototype contains mechanisms for measuring tourists’ adherence to the recommended tours using the Dynamic Time Warping algorithm, which raises new research opportunities on tourists’ behaviour.O desenvolvimento próspero do setor turístico em Portugal nos últimos anos fez da indústria um dos maiores contribuintes para a economia nacional e o maior empregador do país. No ano de 2019, Portugal recebeu um total de 27 milhões de turistas, ultrapassando uma vez mais uma vez o recorde estabelecido no ano anterior. No entanto, o turismo traz também uma série de efeitos secundários negativos não intencionais, tais como overcrowding. A freguesia histórica de Santa Maria Maior em Lisboa está a ser particularmente afetada por este problema. O trabalho desenvolvido nesta dissertação faz parte do projeto de pesquisa Sustainable Tourism Crowding, que visa mitigar o fenómeno de overcrowding nesta freguesia, promovendo uma distribuição equilibrada dos visitantes e incentivando a visita de pontos de interesse sustentáveis. Esta dissertação foca-se no desenvolvimento de uma aplicação móvel protótipo destinada a turistas, através do qual recebem recomendações de visitas sustentáveis. Para validar os requisitos funcionais do protótipo, mais especificamente o processo de criação de visitas, foram desenvolvidos testes unitários, testes de integração, e testes manuais. Para avaliar a usabilidade do protótipo, foi adotada uma abordagem centrada no utilizador durante a fase de conceção, em que foram utilizadas duas técnicas de usabilidade em parceria com o ISTAR (centro de investigação do ISCTE) e com a Junta de Freguesia de Santa Maria Maior, cujos resultados guiaram e validaram as decisões tomadas. O protótipo desenvolvido contém mecanismos para medir a aderência dos turistas às recomendações sugeridas através do algoritmo Dynamic Time Warping, proporcionando novas oportunidades de pesquisa nesta área