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This dissertation investigates how to plan paths for Unmanned Aerial Vehicles (UAV) for the task of covering an environment. Three increasingly complex coverage problems based on the environment that needs to be covered are studied. The dissertation starts with a 2D point coverage problem where the UAV needs to visit a set of sites on the ground plane by flying on a fixed altitude plane parallel to the ground. The UAV has limited battery capacity which may make it infeasible to visit all the points. A novel symbiotic UAV and Unmanned Ground Vehicle (UGV) system where the UGV acts as a mobile recharging station is proposed. A practical, efficient algorithm for solving this problem using Generalized Traveling Salesperson Problem (GTSP) solver is presented. Then the algorithm is extended to a coverage problem that covers 2D regions on the ground with a UAV that can operate in fixed-wing or multirotor mode. The algorithm is demonstrated through proof-of-concept experiments. Then this algorithm is applied to covering 2D regions, not all of which lie on the same plane. This is motivated by bridge inspection application, where the UAV is tasked with visually inspecting planar regions on the bridge. Finally, a general version of the problem where the UAV is allowed to fly in complete 3D space and the environment to be covered is in 3D as well is presented. An algorithm that clusters viewpoints on the surface of a 3D structure and has an UAV autonomously plan online paths to visit all viewpoints is presented. These online paths are re-planned in real time as the UAV obtains new information on the structure and strives to obtain an optimal 3D coverage path. / Doctor of Philosophy / This dissertation investigates how to plan paths for Unmanned Aerial Vehicles (UAV). Three increasingly complex coverage problems based on the environment that needs to be covered are studied. The dissertation starts with a 2D point coverage problem where the UAV needs to visit a set of sites on the ground by flying at a fixed altitude. The UAV has limited battery capacity which may make it impossible to visit all the points. A novel symbiotic UAV and Unmanned Ground Vehicle (UGV) system where the UGV acts as a mobile recharging station is proposed. A practical, efficient algorithm for solving this problem using Generalized Traveling Salesperson Problem (GTSP) solver is presented. Then the algorithm is extended to coverage of 2D regions on the ground with a hybrid UAV. The algorithm is demonstrated through proof-of-concept experiments. Then this algorithm is applied to covering 2D regions on 3D structures. This is motivated by bridge inspection application, where the UAV is tasked with visually inspecting regions on the bridge. Finally, a general version of the problem where the UAV is allowed to fly in 3D space and the environment to be covered is in 3D as well is presented. An algorithm that clusters points on the surface of a 3D structure and has an UAV autonomously plan online paths to visit all viewpoints is presented. These online paths are re-planned in real time as the UAV obtains new information on the structure and strives to obtain an optimal 3D coverage path.

This thesis aims to analyze the effects of geometric imperfections on the load-bearing capacity of high-strength steel grades and how the industry implements these imperfections in Finite Element Method (FEM) modeling. The goal was to examine the industry's implementation of these geometric imperfections in relation to compliance with established standards and regulations. Through conducted interviews, hand calculations, and numerical simulations, the study provided SSAB with a deeper understanding of geometric imperfections. The interview focused on handling geometric imperfections in the manufacturing of truck cranes, exploring various strategies to ensure structural integrity and compliance with industry standards. The company in focus oversized the construction in nominal analyses and followed EN 13001 and internal guidelines to prevent the effects of imperfections. A test specimen from SSAB's laboratory was used as a reference against the simulations. The test specimen consisted of a high-strength steel profile mimicking those used in cranes. The geometry of the test specimen was then applied to the numerical simulations   In numerical simulations, the flat and round sides of the test specimen were compared under compression. When the round part was in compression, the simulation underestimated the moment capacity by approximately 14 kN, equivalent to about 7.1%, compared to the actual test results. When the flat part was in compression, the simulation overestimated the moment capacity by approximately 7 kN, equivalent to 8.4%. The differences between simulations and tests were relatively small, and simulations were deemed quite representative compared to tests.   Simulations with imperfections showed marginal effects on load-bearing capacity. For the profile simulated with imperfections, the load-bearing capacity before failure was 84.5 kN, while the capacity for the profile without imperfections was 82.6 kN, with a difference of 2.24%. No major conclusions regarding the impact of imperfections can be drawn with such a small difference, but it is interesting that the profile with applied imperfections has 2.24% better load-bearing capacity than the one without. The impact of thickness on load-bearing capacity was also examined. The most significant difference noted between the ideal geometry and the one with imperfections was at a thickness of 8 mm. The main reason imperfections made the most difference there is the slenderness. Thinner thicknesses of 2, 4, and 6 mm were so slender that all would be limited by local buckling. For the larger thickness of 10 mm, the idea was that the profile becomes thick and rigid enough to avoid buckling affecting load capacity. In the case of 8 mm, the cross-section was right on the border between cross-section class 3 and 4, where imperfections take a larger part of the cross-section to class 4. It can be concluded that in cases where the part in compression is right on the verge of being so slender that cross-section reduction is almost relevant, imperfections can significantly reduce load capacity. It is noted that thicker profiles can be affected by imperfections much more than slender ones.   Hand calculations revealed differences between calculated and experimental failure loads, varying between 18% and 29%. These differences can be attributed to discrepancies in strength class and the geometry of the test component. Adjusting the strength class to 850 MPa in hand calculations improved the agreement with experiments. Geometric uncertainties include variations in thickness, where a larger thickness increases load capacity. Additional uncertainties arise for the flat part regarding cross-section reduction.   In conclusion, hand calculations align reasonably well with test results, but differences were scattered and challenging to attribute to geometric imperfections. For future studies, a closer examination of the company's method with safety factors for imperfection calculations is suggested, along with investigations into cross-sectional profiles and the transition between cross-section classes. Furthermore, the need for more simulations with different geometries is emphasized to better understand the effects of geometric imperfections.

Nourrie par la rencontre spéculative des disciplines esthético-philosophiques et la démarche opérationnelle du Landscape Urbanism, cette étude part d'une lecture du paysage en termes de "constellation visible" voire de "trame de relations" matérielles et immatérielles entre éléments hétérogènes et contemporains, et, parallèlement, de l'acceptation étymologique du terme infrastructure en tant que "dispositif de support" des activités économiques, socio-culturelles et écologiques d'une communauté. A la lumière de ces définitions de paysage et d'infrastructure, la recherche essaie de répondre à la question principale formulée dans le cadre de la problématique, portant sur la possibilité d'accorder au paysage une "dimension infrastructurelle", propriété qui attribuerait à ce dernier la même connotation dynamique propre aux agents catalyseurs infrastructurels. L'étude de cette dimension infrastructurelle fait ressortir l'émergence d'une caractéristique ontologique du paysage définissable en termes de réseau multipolaire et donc par les relations horizontales et verticales entre ses éléments, liens physiques ou virtuels, matériels ou immatériels, qui lui donnent une cohérence unitaire et le transforment en un tout pourvu du sens (...) / Taking as a starting point on the one hand the consideration of the landscape as a "visible constellation" and a "network of material and immaterial connections" between a range of heterogeneous elements, and, on the other hand, the etymological meaning of the word infrastructure as a "support device" for the economic, socio-cultural and ecological activities of a community, this study is grounded on the interaction between the speculative approach of aesthetic-philosophical disciplines and the Landscape Urbanism operational stratedy (...)

This document investigates a set of projects I call DIY Infrastructure, in which designers are building alternative infrastructural systems. Through these projects, new actors-often non-experts-reveal and re-imagine long-established social and technological relationships which were previously off limits to them. These projects are significant to the study of design and digital media for the following reasons: First, they detail a new area of design. The designers of DIY infrastructure present an expansion of the scope of design coupled with a nuanced and almost paradoxical understanding of infrastructure as an intractable and exceedingly complex problem. At the same time, their work reveals the extensive social and political effects of existing design decisions-the far-reaching consequences of the design decisions which formed existing infrastructure. These decisions are in play across a variety of scales of time and space, affecting individual bodies as much as continental ecosystems, and shaping personal behavior as much as global commerce and trade. Second, they expand the scope of digital media studies. Digital media studies often overlook infrastructure, in spite of their interdependence. Digital media are involved in areas including the control and monitoring of the electrical system, the treatment and movement of water and sewage, and the routing of freight through intermodal shipping systems. The study of DIY infrastructure design, and infrastructure more broadly, exposes the role of digital media in shaping these overlooked aspects of modern life. There is an invisible relationship between digital media, infrastructure, and political authority, and it includes the interdependence of infrastructure and the contingent nature of our ongoing reliance on these complex sociotechnical systems. For example, Cloacina is the project of two activists developing a new municipal waste disposal system in which a decentralized networked system significantly lessens the amount of water used in processing human waste. Another project, Feral Trade Courier, employs the sort of shipping database we might associate with FedEx or UPS to facilitate an alternative shipping infrastructure, in which volunteers transport goods in an ad hoc freight network. I begin by surveying and defining DIY practice, delineating the properties of infrastructure, and determining the ways that those properties and practices can be augmented or diminished by the affordances of digital media. Next, I review the attributes that these DIY infrastructure projects share before revealing their significance through in-depth case studies. Finally, each of these case studies highlights a particular lesson from DIY infrastructure. Feral Trade Courier exposes the role of the social and the subjective in the design of logistics systems. Village Telco and Fluid Nexus show us that the relationship between established infrastructure and DIY infrastructure can be both complementary and antagonistic. Cloacina provides us an example of a way that DIY infrastructure might scale up and effect lasting sociotechnical change. Whether motivated to reveal or overcome dependence on infrastructure, address flaws in its design, or correct externalities generated by its use, new designers have begun to engage with the problem of infrastructure in new ways. This document analyzes these design projects through a series of case studies, synthesizing a new perspective on the study of infrastructure through design and on the scope of digital media research along the way.

Performance goals for a highway system are an indication of the desired system condition, and the level of service to be provided to its users. Setting the appropriate performance goals has a significant impact on the way highway agencies conduct business. With growing needs and limited resources, the consequences of setting different levels of performance goals should be examined and compared to optimize the highway infrastructure needs at the network level. Three interacting sets of costs are typically considered for a complete economic appraisal of highway projects: construction, maintenance and road use costs. Due to the shift in focus from design-and-build mode to the repair-and-maintain mode, this study focuses on maintenance related costs and the road user cost aspects only. Maintenance and rehabilitation activities on pavement infrastructure are ongoing processes that are required for the entire road network. This suggests that for long planning horizons and geographically extensive networks, their application usually results in significant financial needs. Typically, highway agencies have based their policy decisions such as the target condition levels for the system on the budget needs for maintenance and rehabilitation actions. Since in most cases, the funding needs exceed the available budget, the required preventive and routine maintenance activities suffer or are overlooked completely. Failure to timely apply these maintenance actions cause the pavements to deteriorate more rapidly into condition states that require for more expensive rehabilitation actions during the life cycle of the pavement. Over time, a vicious cycle is instigated in which the maintenance and rehabilitation needs of the network keep increasing each year. Although most highway administrators acknowledge the fact that pavement preservation is perhaps the most effective way of using the limited budgets available, the costs associated with deferring maintenance actions is oftentimes overlooked when establishing performance goals for the system. Road user costs in the form of costs for vehicle operation have been recognized as another large component of the total transportation related costs. These costs are then arguably the most important to consider for a complete economic appraisal. Ironically, they are also often disregarded while making important policy decisions. Other road user costs such as those related to the impact of traffic congestion and detours caused by construction and maintenance activities are difficult to quantify and were not accounted for in this study. Although it is widely accepted that establishing suitable performance goal is critical for system maintenance and preservation, a framework that considers the inter-relationship between conflicting objectives of minimum maintenance and rehabilitation costs, deferred maintenance costs, and vehicle operating costs to the users does not exist. This thesis proposes a methodological framework that is aimed at assisting highway agencies with the problem of objectively analyzing policy decisions in terms of the performance goals for their highway networks that would minimize the total transport costs to the society. In a case study of the proposed framework, the highway network managed by the Texas Department of Transportation was examined for different performance goals. The results from the case study indicate that setting lower performance goals lead to savings in the M&R needs, but at the same time, they also significantly increase the exogenous costs such as deferred maintenance costs and the vehicle operating costs. / text

Infrastructure plays an instrumental role in the shaping of the landscape across many scales and is a critical human component within the landscape, yet these systems have tended to ignore the function of appearance and aesthetics in their design. Consequently, the relationship between our infrastructure, the environment, and us has become increasingly opaque. The majority of the vast infrastructure systems that weave throughout the landscape promote a mono-functional agenda which is relegated to the background of our everyday experiences. By investigating the traditional methods of designing infrastructure, we can begin to understand how to integrate aesthetics into the design of infrastructure. This is explored through one of the largest infrastructure systems in the United States; flood control. Flood control infrastructure in is an extensive system that has formed a protective barrier between human and natural processes for over 200 years. Its largest component, the levee, is an elegantly simple structure that contains many layers of significant cultural and historic aesthetic narratives. This thesis focuses on the levee as an infrastructure that mediates between natural processes and human development and studies how it can perform aesthetically to convey new meaning and value. What is the potential of the levee to become expressive in our lives, and be designed in such a way to move us? This new infrastructural paradigm explores the implications of utilizing aesthetics as an expressive and significant function of levee design that can inform and inspire the public and define a new dialogue between man, nature, and technology. / Master of Landscape Architecture

<p>Water infrastructure forms a critical sector of our social system and provides goods and services for public health, the natural environment, economic safety, various businesses, and government operations. In the United States (US), drinking water is supplied nationally through one million miles of pipes, most of which were installed in the early to mid-20th century with a life span of 75 to 100 years. Along with this fact, water bills which are rising faster than inflation, result in communities grappling with aging water systems, fewer water resources, and extreme weather. The federal government’s share of capital investment for water infrastructure has fallen from 31% in 1977 to 4% in 2017. Regional and state expenditure has accounted for a much larger share as federal aid for water infrastructure capital needs has declined. This has led to water rates rising to cover the costs of replacing and upgrading water infrastructure in many communities across the country. They are struggling to meet such costs through local rates and fees.</p><p>Over the next 20 years, more than 56 million new users are expected to connect to centralized treatment systems, and $271 billion is needed to meet current and future demands. However, the investment in critical water infrastructure is currently only meeting a fraction of the funding need. In 2019, the total capital spending on water infrastructure at all levels was $48 billion, while investment needs totaled $129 billion, creating an $81 billion gap. As such, the most recent American Society of Civil Engineers’ Infrastructure Report Card assigned a D to the drinking water infrastructure and a D+ to the nation’s wastewater infrastructure. Ineffectual and wasteful investment in the water sector has caused an adverse effect on grades in the infrastructure report card for water infrastructures. Moreover, this may negatively impact water-reliant sectors and water-related infrastructures due to the economic ripple effect.</p><p>This research has developed a data-driven strategic investment decision support system to close the existing water infrastructure investment gap and reduce the vulnerability of aging water infrastructure. The first phase of this study was to determine the causes affecting the grades in the infrastructure report card for drinking water and wastewater infrastructure and contributing to any latent threats and prolonged risks. It uses data-driven approaches based on analysis of existing ineffective improvement methods and recommendations. It attempts to leverage a data-driven supervised statistical learning method to capture the complex relationships between new challenges and the growing demand for water infrastructure needs. The ultimate outcome of this phase is a research approach to minimize water and wastewater vulnerability and close the investment gap to help create a paradigm shift in the current state of practice. Furthermore, improving the resiliency of and increasing investments in the water and wastewater infrastructure will lead to a resilient, efficient, and reliable water future and protect the public health of future generations.</p><p>The second phase of this study was to predict the economic benefits of additional federal support in water infrastructure among interdependent sectors within an economic system to facilitate the federal government’s share of capital investment. It conducts ripple effects analysis, which predicts the effectiveness of water infrastructure capital investment using historical economic data. It explores how federal capital investment in water infrastructure spreads economic benefits within an interdependent system. This phase was conducted at the federal level using the interindustry-macro model that analyzes macroeconomic data, including over 400 sectors. Investments that are coordinated at the federal, state, and local level will help control and stabilize rising water rates across the US.</p><p>The third phase of this study was to conduct a cost-benefit assessment in terms of private, financial, economic, and efficiency considerations using nominal and real terms to maximize the benefit of investing in the water sector and reduce the vulnerability of water infrastructures. In order to measure the costs and benefits of a strategy to maximize the efficiency of limited budgets and resources, this phase conducts a cost-benefit analysis due to the investment costs for rehabilitating and improving water infrastructures using historical economic and financial data. The long-term financial framework, including considerations of deep uncertainties so that decision-makers can understand the benefit of investing assets for an optimal level versus the cost of doing nothing and allowing the asset to run to failure is developed using the cost-benefit assessment.</p><p>Finally, a data-driven strategic investment decision support system that helps governments make water infrastructure development plans and infrastructure investment decisions in the water sector is presented. It can help governments with designing a novel system or modifying existing ineffective assessment methods and recommendations aimed at minimizing the mismatch in the water infrastructure investment gap between current spending levels and funding needs. Furthermore, minimizing the risks of ineffectual and wasteful water sector investment through rehabilitating and improving water infrastructures in a rational manner will lead to improved grades in the infrastructure report card and the resiliency of interrelated infrastructures and sectors.</p>

Maintenance of transport infrastructure assets is widely advocated as the key in minimizing current and future costs of the transportation network. While effective maintenance decisions are often a result of engineering skills and practical knowledge, efficient decisions must also account for the net result over an asset's life-cycle. One essential aspect in the long term perspective of transport infrastructure maintenance is to proactively estimate maintenance needs. In dealing with immediate maintenance actions, support tools that can prioritize potential maintenance candidates are important to obtain an efficient maintenance strategy. This dissertation consists of five individual research papers presenting a microdata analysis approach to transport infrastructure maintenance. Microdata analysis is a multidisciplinary field in which large quantities of data is collected, analyzed, and interpreted to improve decision-making. Increased access to transport infrastructure data enables a deeper understanding of causal effects and a possibility to make predictions of future outcomes. The microdata analysis approach covers the complete process from data collection to actual decisions and is therefore well suited for the task of improving efficiency in transport infrastructure maintenance. Statistical modeling was the selected analysis method in this dissertation and provided solutions to the different problems presented in each of the five papers. In Paper I, a time-to-event model was used to estimate remaining road pavement lifetimes in Sweden. In Paper II, an extension of the model in Paper I assessed the impact of latent variables on road lifetimes; displaying the sections in a road network that are weaker due to e.g. subsoil conditions or undetected heavy traffic. The study in Paper III incorporated a probabilistic parametric distribution as a representation of road lifetimes into an equation for the marginal cost of road wear. Differentiated road wear marginal costs for heavy and light vehicles are an important information basis for decisions regarding vehicle miles traveled (VMT) taxation policies. In Paper IV, a distribution based clustering method was used to distinguish between road segments that are deteriorating and road segments that have a stationary road condition. Within railway networks, temporary speed restrictions are often imposed because of maintenance and must be addressed in order to keep punctuality. The study in Paper V evaluated the empirical effect on running time of speed restrictions on a Norwegian railway line using a generalized linear mixed model.