2,199 research outputs found
Natural and Technological Hazards in Urban Areas
Natural hazard events and technological accidents are separate causes of environmental impacts. Natural hazards are physical phenomena active in geological times, whereas technological hazards result from actions or facilities created by humans. In our time, combined natural and man-made hazards have been induced. Overpopulation and urban development in areas prone to natural hazards increase the impact of natural disasters worldwide. Additionally, urban areas are frequently characterized by intense industrial activity and rapid, poorly planned growth that threatens the environment and degrades the quality of life. Therefore, proper urban planning is crucial to minimize fatalities and reduce the environmental and economic impacts that accompany both natural and technological hazardous events
LIPIcs, Volume 251, ITCS 2023, Complete Volume
LIPIcs, Volume 251, ITCS 2023, Complete Volum
Towards electric bus system: planning, operating and evaluating
The green transformation of public transportation is an indispensable way to achieve carbon neutrality. Governments and authorities are vigorously implementing electric bus procurement and charging infrastructure deployment programs. At this primary but urgent stage, how to reasonably plan the procurement of electric buses, how to arrange the operation of the heterogeneous fleet, and how to locate and scale the infrastructure are urgent issues to be solved. For a smooth transition to full electrification, this thesis aims to propose systematic guidance for the fleet and charging facilities, to ensure life-cycle efficiency and energy conservation from the planning to the operational phase.One of the most important issues in the operational phase is the charge scheduling for electric buses, a new issue that is not present in the conventional transit system. How to take into account the charging location and time duration in bus scheduling and not cause additional load peaks to the grid is the first issue being addressed. A charging schedule optimization model is constructed for opportunity charging with battery wear and charging costs as optimization objectives. Besides, the uncertainty in energy consumption poses new challenges to daily operations. This thesis further specifies the daily charging schedules with the consideration of energy consumption uncertainty while safeguarding the punctuality of bus services.In the context of e-mobility systems, battery sizing, charging station deployment, and bus scheduling emerge as crucial factors. Traditionally these elements have been approached and organized separately with battery sizing and charging facility deployment termed planning phase problems and bus scheduling belonging to operational phase issues. However, the integrated optimization of the three problems has advantages in terms of life-cycle costs and emissions. Therefore, a consolidated optimization model is proposed to collaboratively optimize the three problems and a life-cycle costs analysis framework is developed to examine the performance of the system from both economic and environmental aspects. To improve the attractiveness and utilization of electric public transportation resources, two new solutions have been proposed in terms of charging strategy (vehicle-to-vehicle charging) and operational efficiency (mixed-flow transport). Vehicle-to-vehicle charging allows energy to be continuously transmitted along the road, reducing reliance on the accessibility and deployment of charging facilities. Mixed flow transport mode balances the directional travel demands and facilities the parcel delivery while ensuring the punctuality and safety of passenger transport
The Distributional Impacts of Economic Development Incentives: Three Essays
Economic Development Incentives (EDIs) are among the most common and costly tools used by state and local governments in the United States to promote economic development. While literature has predominantly focused on the efficiency of EDIs, comparatively less focus has been paid to the distributional impacts of business attraction or the impact on individual welfare. In three papers, this dissertation seeks to better understand and evaluate how business attraction supported by EDIs impacts current residents. The first paper critiques EDI evaluations that focus on bottom-line growth instead of metrics that can show changes to the quality of life and welfare of current resident. A new framework, Distributive Welfare Evaluations, is proposed. A second paper examines how business attraction impacts wages and employment rates in local economies, using large warehouses as a natural experiment. Analysis shows that jobs were filled by shifting commuting patterns and had minimal benefits for incumbent workers. Finally, a third paper, co-authored with Jeremy Moulton and Scott Wentland, measures the impacts of EDI announcements on housing markets. We find highly variable results across 114 cases but demonstrate significant increases in prices when many jobs are promised. Together, evidence contributes to a growing body of work arguing that EDIs have limited or even negative impacts on the welfare of current residents and can contribute to growing inequalityDoctor of Philosoph
Ypsilanti Histories: A Look Back at the Last Fifty Years
In commemoration of their city\u27s bicentennial, the people of Ypsilanti look back on the dramatic changes that the last fifty years brought to this small town in southeastern Michigan. Drawing on archival research, published sources, and personal recollections, Ypsilanti Histories explores the government, educational institutions, businesses, community organizations, neighborhoods, and individuals that have defined Ypsilanti since 1973.
As befits the rich diversity of the community, Ypsilanti Histories captures a range of experiences. It explores the controversies that have rocked the city from the university mascot to school consolidation, while also celebrating the city\u27s oldest African American civic organization and the pioneering Ypsilanti Heritage Foundation. Beloved businesses like the Ypsilanti Food Coop and the Ypsilanti Thrift Shop are profiled here as are some of the city\u27s greatest heroes including a Medal of Honor recipient. The effects of deindustrialization are documented as are the challenges that this brought to Michigan Avenue, Depot Town, and various neighborhoods. Education has long been central to Ypsilanti\u27s history, and Ypsilanti Histories examines changes at the city\u27s high school and Eastern Michigan University.
The authors of Ypsilanti Histories are amateur and professional historians who call Ypsilanti home. Many personally witnessed the events they describe, and some played a key role in the histories they tell. Ypsilanti Histories: A Look Back at the Last Fifty Years is edited by John McCurdy, Bill Nickels, Evan Milan, and Sarah Zawacki.https://commons.emich.edu/books/1011/thumbnail.jp
Under construction: infrastructure and modern fiction
In this dissertation, I argue that infrastructural development, with its technological promises but widening geographic disparities and social and environmental consequences, informs both the narrative content and aesthetic forms of modernist and contemporary Anglophone fiction. Despite its prevalent material forms—roads, rails, pipes, and wires—infrastructure poses particular formal and narrative problems, often receding into the background as mere setting. To address how literary fiction theorizes the experience of infrastructure requires reading “infrastructurally”: that is, paying attention to the seemingly mundane interactions between characters and their built environments. The writers central to this project—James Joyce, William Faulkner, Karen Tei Yamashita, and Mohsin Hamid—take up the representational challenges posed by infrastructure by bringing transit networks, sanitation systems, and electrical grids and the histories of their development and use into the foreground. These writers call attention to the political dimensions of built environments, revealing the ways infrastructures produce, reinforce, and perpetuate racial and socioeconomic fault lines. They also attempt to formalize the material relations of power inscribed by and within infrastructure; the novel itself becomes an imaginary counterpart to the technologies of infrastructure, a form that shapes and constrains what types of social action and affiliation are possible
Integrating materials supply in strategic mine planning of underground coal mines
In July 2005 the Australian Coal Industry’s Research Program (ACARP) commissioned Gary Gibson to identify constraints that would prevent development production rates from achieving full capacity. A “TOP 5” constraint was “The logistics of supply transport distribution and handling of roof support consumables is an issue at older extensive mines immediately while the achievement of higher development rates will compound this issue at most mines.” Then in 2020, Walker, Harvey, Baafi, Kiridena, and Porter were commissioned by ACARP to investigate Australian best practice and progress made since Gibson’s 2005 report. This report was titled: - “Benchmarking study in underground coal mining logistics.” It found that even though logistics continue to be recognised as a critical constraint across many operations particularly at a tactical / day to day level, no strategic thought had been given to logistics in underground coal mines, rather it was always assumed that logistics could keep up with any future planned design and productivity. This subsequently meant that without estimating the impact of any logistical constraint in a life of mine plan, the risk of overvaluing a mining operation is high.
This thesis attempts to rectify this shortfall and has developed a system to strategically identify logistics bottlenecks and the impacts that mine planning parameters might have on these at any point in time throughout a life of mine plan. By identifying any logistics constraints as early as possible, the best opportunity to rectify the problem at the least expense is realised. At the very worst if a logistics constraint was unsolvable then it could be understood, planned for, and reflected in the mine’s ongoing financial valuations. The system developed in this thesis, using a suite of unique algorithms, is designed to “bolt onto” existing mine plans in the XPAC mine scheduling software package, and identify at a strategic level the number of material delivery loads required to maintain planned productivity for a mining operation. Once an event was identified the system then drills down using FlexSim discrete event simulation to a tactical level to confirm the predicted impact and understand if a solution can be transferred back as a long-term solution. Most importantly the system developed in this thesis was designed to communicate to multiple non-technical stakeholders through simple graphical outputs if there is a risk to planned production levels due to a logistics constraint
A Methodology to Enable Concurrent Trade Space Exploration of Space Campaigns and Transportation Systems
Space exploration campaigns detail the ways and means to achieve goals for our human spaceflight programs. Significant strategic, financial, and programmatic investments over long timescales are required to execute them, and therefore must be justified to decision makers. To make an informed down-selection, many alternative campaign designs are presented at the conceptual-level, as a set and sequence of individual missions to perform that meets the goals and constraints of the campaign, either technical or programmatic. Each mission is executed by in-space transportation systems, which deliver either crew or cargo payloads to various destinations. Design of each of these transportation systems is highly dependent on campaign goals and even small changes in subsystem design parameters can prompt significant changes in the overall campaign strategy. However, the current state of the art describes campaign and vehicle design processes that are generally performed independently, which limits the ability to assess these sensitive impacts. The objective of this research is to establish a methodology for space exploration campaign design that represents transportation systems as a collection of subsystems and integrates its design process to enable concurrent trade space exploration. More specifically, the goal is to identify existing campaign and vehicle design processes to use as a foundation for improvement and eventual integration.
In the past two decades, researchers have adopted terrestrial logistics and supply chain optimization processes to the space campaign design problem by accounting for the challenges that accompany space travel. Fundamentally, a space campaign is formulated as a network design problem where destinations, such as orbits or surfaces of planetary bodies, are represented as nodes with the routes between them as arcs. The objective of this design problem is to optimize the flow of commodities within network using available transport systems. Given the dynamic nature and the number of commodities involved, each campaign can be modeled as a time-expanded, generalized multi-commodity network flow and solved using a mixed integer programming algorithm. To address the challenge of modeling complex concept of operations (ConOps), this formulation was extended to include paths as a set of arcs, further enabling the inclusion of vehicle stacks and payload transfers in the campaign optimization process. Further, with the focus of transportation system within this research, the typical fixed orbital nodes in the logistics network are modified to represent ranges of orbits, categorized by their characteristic energy. This enables the vehicle design process to vary each orbit in the mission as it desires to find the best one per vehicle.
By extension, once integrated, arc costs of dV and dT are updated each iteration. Once campaign goals and external constraints are included, the formulated campaign design process generates alternatives at the conceptual level, where each one identifies the optimal set and sequence of missions to perform.
Representing transportation systems as a collection of subsystems introduces challenges in the design of each vehicle, with a high degree of coupling between each subsystem as well as the driving mission. Additionally, sizing of each subsystem can have many inputs and outputs linked across the system, resulting in a complex, multi-disciplinary analysis, and optimization problem. By leveraging the ontology within the Dynamic Rocket Equation Tool, DYREQT, this problem can be solved rapidly by defining each system as a hierarchy of elements and subelements, the latter corresponding to external subsystem-level sizing models. DYREQT also enables the construction of individual missions as a series of events, which can be directly driven and generated by the mission set found by the campaign optimization process. This process produces sized vehicles iteratively by using the mission input, subsystem level sizing models, and the ideal rocket equation.
By conducting a literature review of campaign and vehicle design processes, the different pieces of the overall methodology are identified, but not the structure. The specific iterative solver, the corresponding convergence criteria, and initialization scheme are the primary areas for experimentation of this thesis. Using NASA’s reference 3-element Human Landing System campaign, the results of these experiments show that the methodology performs best with the vehicle sizing and synthesis process initializing and a path guess that minimizes dV. Further, a converged solution is found faster using non-linear Gauss Seidel fixed point iteration over Jacobi and set of convergence criteria that covers vehicle masses and mission data.
To show improvement over the state of the art, and how it enables concurrent trade studies, this methodology is used at scale in a demonstration using NASA’s Design Reference Architecture 5.0. The LH2 Nuclear Thermal Propulsion (NTP) option is traded with NH3and H2O at the vehicle-level as a way to show the impacts of alternative propellants on the vehicle sizing and campaign strategy. Martian surface stay duration is traded at the campaign-level through two options: long-stay and short-stay. The methodology was able to produce four alternative campaigns over the course of two weeks, which provided data about the launch and aggregation strategy, mission profiles, high-level figures of merit, and subsystem-level vehicle sizes for each alternative. Expectedly, with their lower specific impulses, alternative NTP propellants showed significant growth in the overall mass required to execute each campaign, subsequently represented the number of drop tanks and launches. Further, the short-stay campaign option showed a similar overall mass required compared to its long-stay counterpart, but higher overall costs even given the fewer elements required. Both trade studies supported the overall hypothesis and that integrating the campaign and vehicle design processes addresses the coupling between then and directly shows the impacts of their sensitivities on each other. As a result, the research objective was fulfilled by producing a methodology that was able to address the key gaps identified in the current state of the art.Ph.D
Cross-Supply Chain Collaboration Platform for Pallet Management
Standardized pallets are an important factor in today's logistics sector to enable efficient processes in transport, storage and handling. By using an open exchange pool for pallets, additional opportunities arise for horizontal and vertical collaboration of various actors from different supply chains. The dissertation "Cross-Supply Chain Collaboration Platform for Pallet Management" investigates the potential of a digital platform for such cross-actor collaboration in pallet management. The designed platform has special mechanisms for balancing pallet debts that arise in the network and for joint planning of empty pallet flows. Therefore, the impact of the designed platforms on logistic processes, especially transports, is explored using simulation modeling. Furthermore, blockchain technology is investigated, which could be used for the implementation of the platform concept and could generate trust in a network of unknown actors. In this context, an empirical online-experiment is used to analyze in a differentiated way which specific features of the blockchain technology generate trust in technology and how these features interact with each other
To the Last Drop: Affective Economies of Extraction and Sentimentality
The romance of extraction underlies and partly defines Western modernity and our cultural imaginaries. Combining affect studies and environmental humanities, this volume analyzes societies' devotion to extraction and fossil resources. This devotion is shaped by a nostalgic view on settler colonialism as well as by contemporary "affective economies" (Sara Ahmed). The contributors examine the links between forms of extractivism and gendered discourses of sentimentality and the ways in which cultural narratives and practices deploy the sentimental mode (in plots of attachment, sacrifice, and suffering) to promote or challenge extractivism
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