Esta Tese apresenta uma contribuição para avaliação da comunicação digital na operação de veículos aéreos não tripulados (VANT) no ambiente aeronáutico. A comunicação digital aeronáutica relaciona-se diretamente ao nível de segurança crítica desejado para o controle do fluxo de tráfego aéreo, por parte de autoridades e de órgãos normativos, os quais possuem como objetivo tornar a comunicação uniforme para todos os continentes. Diversas são as discussões acerca do nível de segurança crítica que a comunicação digital entre VANT e controle em terra possa exibir, sempre buscando redução da exposição a riscos inerentes à operação desse tipo de veículo. Nesse contexto, a proposta desta Tese é avaliar a segurança na comunicação digital, por meio do uso de injeção de falhas, para operações de veículos aéreos não tripulados. Este trabalho descreve a importância de analisar as interferências causadas por falhas na comunicação digital, relacionadas ao envio de mensagens entre o órgão de controle e a aeronave não tripulada. Também são definidos quais os tipos de falhas que causam um maior impacto na comunicação, bem como quais os parâmetros que devem ser utilizados para manipulação das variáveis de falhas na comunicação. Para atender a avaliação proposta, foi utilizado o ambiente simulado que reúne as características do ambiente aeronáutico, denominado PipE-SEC (Plataforma Integrada para Ensaios de Sistemas Embarcados Críticos), bem como o protocolo CPDLC (Controller-Pilot Data Link Communications) para troca de mensagens digitais. / This thesis presents a contribution to the evaluation of digital communication in the operation of unmanned aerial vehicles (UAV) in the aeronautical environment. Aeronautical digital communication relates directly to the critical safety level required for controlling the air traffic flow by authorities and regulatory agencies, which are aimed at making communication uniform for all continents. There are several discussions about the safety critical level that digital communication between UAVs and ground control can display, always seeking to reduce exposure to risks inherent in the operation of such vehicles. In this context, the proposal of this thesis is to evaluate the safety in digital communication, through the use of fault injection for operations of UAV. This work describes the importance of analyzing the interference caused by faults in digital communication related to sending messages between the control agency and the UAV. There are also defined what types of faults cause a greater impact on communication as well as which parameters should be used to simulate communication faults. To answer the proposed evaluation, we used the simulated environment that combines the features of the aeronautical environment, called PIpE-SEC (Integrated Platform for Test Critical Embedded Systems), as well as the protocol CPDLC (Controller-Pilot Data Link Communications) to exchange digital messages.

Cities are composed of multiple interconnected, interdependent infrastructure networks. These networks are expected to continuously operate at near 100\% of their designed service capacities. When the operation of just one of these networks is disrupted the effects are often not contained to a single network. How these networks function and interact is critically important in increasing urban community resilience when subjected to stochastic disruptions. Despite apparent differences in the physical qualities of both infrastructure and cities this work, uses principles of complex network analysis to reveal stunning similarities in the functional topology of infrastructure networks around the globe. Network based models are used to demonstrate how failures cascade between infrastructure networks. The severity of these cascades is shown to be influenced by population, design decisions, and localized variance within the larger infrastructure networks. These results are important for all design, maintenance, retrofitting, and resilience aspects of urban communities.

Esta Tese apresenta uma contribuição para avaliação da comunicação digital na operação de veículos aéreos não tripulados (VANT) no ambiente aeronáutico. A comunicação digital aeronáutica relaciona-se diretamente ao nível de segurança crítica desejado para o controle do fluxo de tráfego aéreo, por parte de autoridades e de órgãos normativos, os quais possuem como objetivo tornar a comunicação uniforme para todos os continentes. Diversas são as discussões acerca do nível de segurança crítica que a comunicação digital entre VANT e controle em terra possa exibir, sempre buscando redução da exposição a riscos inerentes à operação desse tipo de veículo. Nesse contexto, a proposta desta Tese é avaliar a segurança na comunicação digital, por meio do uso de injeção de falhas, para operações de veículos aéreos não tripulados. Este trabalho descreve a importância de analisar as interferências causadas por falhas na comunicação digital, relacionadas ao envio de mensagens entre o órgão de controle e a aeronave não tripulada. Também são definidos quais os tipos de falhas que causam um maior impacto na comunicação, bem como quais os parâmetros que devem ser utilizados para manipulação das variáveis de falhas na comunicação. Para atender a avaliação proposta, foi utilizado o ambiente simulado que reúne as características do ambiente aeronáutico, denominado PipE-SEC (Plataforma Integrada para Ensaios de Sistemas Embarcados Críticos), bem como o protocolo CPDLC (Controller-Pilot Data Link Communications) para troca de mensagens digitais. / This thesis presents a contribution to the evaluation of digital communication in the operation of unmanned aerial vehicles (UAV) in the aeronautical environment. Aeronautical digital communication relates directly to the critical safety level required for controlling the air traffic flow by authorities and regulatory agencies, which are aimed at making communication uniform for all continents. There are several discussions about the safety critical level that digital communication between UAVs and ground control can display, always seeking to reduce exposure to risks inherent in the operation of such vehicles. In this context, the proposal of this thesis is to evaluate the safety in digital communication, through the use of fault injection for operations of UAV. This work describes the importance of analyzing the interference caused by faults in digital communication related to sending messages between the control agency and the UAV. There are also defined what types of faults cause a greater impact on communication as well as which parameters should be used to simulate communication faults. To answer the proposed evaluation, we used the simulated environment that combines the features of the aeronautical environment, called PIpE-SEC (Integrated Platform for Test Critical Embedded Systems), as well as the protocol CPDLC (Controller-Pilot Data Link Communications) to exchange digital messages.

abstract: Nowadays there is a pronounced interest in the need for sustainable and reliable infrastructure systems to address the challenges of the future infrastructure development. This dissertation presents the research associated with understanding various sustainable and reliable design alternatives for water distribution systems. Although design of water distribution networks (WDN) is a thoroughly studied area, most researchers seem to focus on developing algorithms to solve the non-linear hard kind of optimization problems associated with WDN design. Cost has been the objective in most of the previous studies with few models considering reliability as a constraint, and even fewer models accounting for the environmental impact of WDN. The research presented in this dissertation combines all these important objectives into a multi-objective optimization framework. The model used in this research is an integration of a genetic algorithm optimization tool with a water network solver, EPANET. The objectives considered for the optimization are Life Cycle Costs (LCC) and Life Cycle Carbon Dioxide (CO2) Emissions (LCE) whereby the system reliability is made a constraint. Three popularly used resilience metrics were investigated in this research for their efficiency in aiding the design of WDNs that are able to handle external natural and man-made shocks. The best performing resilience metric is incorporated into the optimization model as an additional objective. Various scenarios were developed for the design analysis in order to understand the trade-offs between different critical parameters considered in this research. An approach is proposed and illustrated to identify the most sustainable and resilient design alternatives from the solution set obtained by the model employed in this research. The model is demonstrated by using various benchmark networks that were studied previously. The size of the networks ranges from a simple 8-pipe system to a relatively large 2467-pipe one. The results from this research indicate that LCE can be reduced at a reasonable cost when a better design is chosen. Similarly, resilience could also be improved at an additional cost. The model used in this research is more suitable for water distribution networks. However, the methodology could be adapted to other infrastructure systems as well. / Dissertation/Thesis / Ph.D. Construction 2012

abstract: Interpersonal communications during civil infrastructure systems operation and maintenance (CIS O&M) are processes for CIS O&M participants to exchange critical information. Poor communications that provide misleading information can jeopardize CIS O&M safety and efficiency. Previous studies suggest that communication contexts and features could be indicators of communication errors and relevant CIS O&M risks. However, challenges remain for reliable prediction of communication errors to ensure CIS O&M safety and efficiency. For example, existing studies lack a systematic summarization of risky contexts and features of communication processes for predicting communication errors. Limited studies examined quantitative methods for incorporating expert opinions as constraints for reliable communication error prediction. How to examine mitigation strategies (e.g., adjustments of communication protocols) for reducing communication-related CIS O&M risks is also challenging. The main reason is the lack of causal analysis about how various factors influence the occurrences and impacts of communication errors so that engineers lack the basis for intervention. This dissertation presents a method that integrates Bayesian Network (BN) modeling and simulation for communication-related risk prediction and mitigation. The proposed method aims at tackling the three challenges mentioned above for ensuring CIS O&M safety and efficiency. The proposed method contains three parts: 1) Communication Data Collection and Error Detection – designing lab experiments for collecting communication data in CIS O&M workflows and using the collected data for identifying risky communication contexts and features; 2) Communication Error Classification and Prediction – encoding expert knowledge as constraints through BN model updating to improve the accuracy of communication error prediction based on given communication contexts and features, and 3) Communication Risk Mitigation – carrying out simulations to adjust communication protocols for reducing communication-related CIS O&M risks. This dissertation uses two CIS O&M case studies (air traffic control and NPP outages) to validate the proposed method. The results indicate that the proposed method can 1) identify risky communication contexts and features, 2) predict communication errors and CIS O&M risks, and 3) reduce CIS O&M risks triggered by communication errors. The author envisions that the proposed method will shed light on achieving predictive control of interpersonal communications in dynamic and complex CIS O&M. / Dissertation/Thesis / Doctoral Dissertation Civil, Environmental and Sustainable Engineering 2020

No description available.

This dissertation contains an examination of the problem of reconfiguration for restoration in critical infrastructure systems, with regard for the prioritization of those systems and the relationships between them. The complexity of the reconfiguration problem is demonstrated, and previous efforts to present solutions to the problem are discussed. This work provides a number of methods by which reconfiguration for restoration of an arbitrary number of prioritized interdependent critical infrastructure systems can be achieved. A method of modeling systems called Graph Trace Analysis is used to enable generic operation on various system types, and a notation for writing algorithms with Graph Trace analysis models is presented. The algorithms described are compared with each other and with prior work when run on a model of actual electrical distribution systems. They operate in a greedy fashion, attempting to restore loads in decreasing priority order. The described algorithms are also run on example models to demonstrate the ability to reconfigure interdependent infrastructure systems and systems which do not operate radially. / Ph. D.

No description available.

Water distribution systems are critical infrastructure systems enabling the social and economic welfare of a community. While normal failures are expected and repaired quickly, low-probability and high consequence disruptive events have potential to cause severe damage to the infrastructure and significantly reduce their performance or even stop their function altogether. Resilient infrastructure is a necessary component towards achieving resilient and sustainable communities. Resilience concepts allow improved decision making in relation with risk assessment and management in water utilities. However, in order to operationalize infrastructure resilience concepts, it is fundamental to develop practical resilience assessment methods such as the methodology and tool proposed in this research, named Effective Resilience Assessment Methodology for Utilities (ERASMUS). ERASMUS utilizes a stochastic simulation model to evaluate the probability of resilient response from a water distribution system in case of disruption. This methodology utilizes a parametric concept of resilience, in which a resilient infrastructure system is defined in terms of a set of performance parameters compared with their socially acceptable values under a variety of disruptive events. The methodology is applied to two actual water distribution networks in the East and West coasts of the US. / Ph. D.

This dissertation brings together the areas of safety science and operations management through a mixed-methods approach to investigate the complex relationships between two, often conflicting, organizational goals - efficiency and safety, in sociotechnical systems (STSs). This research mainly focuses on production pressure (PrP) which is considered as one of the main negative outcomes of overprioritizing the efficiency aspect of STSs. This work seeks to introduce novel methodologies for assessing PrP in real time for the purpose of mitigating its risks and unwanted consequences, particularly in safety critical environments such as traffic control centers (TCCs). Essay 1 concentrates on the theoretical underpinnings of PrP by systematically reviewing the existing literature to clarify and unify the concept under the context of safety science. It identifies key factors contributing to PrP, its negative effects on safety performance in various industries, and potential mitigation strategies. By doing so, this essay contributes to the field through laying the groundwork for more effective management strategies to improve workplace safety. Essay 2 addresses a significant gap identified in Essay 1 by developing a methodology based on Data Envelopment Analysis (DEA) for the ongoing measurement and monitoring of PrP. This innovative approach introduces a quantitative mechanism that juxtaposes efficiency and safety related outcomes of hourly performance in safety critical environments. This proposed method allows for a detailed analysis of performance dynamics within STSs. The practical application of this model is demonstrated through its implementation in the infrastructure management system of INFRABEL, the Belgian National Railroad Company. Essay 3 advances the conversation by tackling the predictive limitations of the DEA model established in Essay 2. It integrates Machine Learning (ML) techniques with DEA to develop an innovative method for forecasting near-future PrP levels for proactive management of safety risks. The major contribution of Essay 3 is the novel interface between ML and DEA that can improve decision-making capabilities of managers in safety-critical STSs through real-time monitoring and predictive analytics. Together, these studies contribute to the theoretical discussions around PrP and present practical solutions to longstanding challenges in safety science and operational management. / Doctor of Philosophy / In today's increasingly complex world, the systems that run our industries, from traffic control to healthcare, face a dilemmatic balance between pushing for higher productivity and ensuring safety. This dissertation explores the trade-offs between efficiency and safety which has become more pronounced with the advancement of technology. Traditional safety approaches which used to be effective in simpler systems, struggle in modern STSs where causes and effects are not linear but tangled in a web of unpredictable interactions. Production pressure (PrP), at the core of the mentioned balance, is the drive to maximize output and efficiency, often at the expense of safety. This pressure can lead to unintended and sometimes catastrophic outcomes in the long term, especially in environments where safety is critical, such as rail traffic control centers. Despite its vital impact, there has been a noticeable gap in understanding and managing PrP. In fact, existing safety frameworks are struggling to capture the dynamic nature of PrP, consequently, its real-time measurement and control remain difficult to achieve. This work, therefore, tries to broaden our understanding of PrP and to develop methods to monitor, measure, and predict it, to equip managers and policymakers with the tools to navigate the efficiency-safety dichotomy more effectively. Through a series of essays, this dissertation reviews the current state of knowledge on PrP to identify its sources and impacts and also innovates a novel approach to quantify PrP in real-time and predict its future trends.