482 research outputs found

    An Emulation Framework for Evaluating V2X Communications in C-ITS Applications

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    C-ITS enhances transportation systems with advanced communication tech, enabling vehicle-to-vehicle and vehicle-to-infrastructure data exchange for real-time decision-making. The thesis explores C-ITS concepts, DSRC, and C-V2X tech, and proposes a versatile C-ITS framework for app prototyping and communication evaluation. Real-world tests and simulations validate its potential to improve road safety and efficiency, suggesting integration opportunities for stakeholders and promoting a smarter, sustainable transportation ecosystem

    The Implementation of Time Management Solution

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    This project proposes a technical solution that will improve the time tracking capabilities of the software department at Diagnostic Product Corporation (DPC). Currently, each developer submits ad-hoc monthly reports indicating how he or she spends their time. This is problematic for management since there is no standard methodology for recording time spent by each developer. Also, there is not a central repository for collecting this data, resulting in management not being able to accurately interpret how the staff is used from project to project. The goal of this project is the development of an application utilizing a networked database that would allow multiple user access to needed data, as well as reports that can be used by developers and management to interpret time spent. Implementing this system would give management the ability to better assess the needs of the department and the various projects within the department

    A Web-Based Collaborative Multimedia Presentation Document System

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    With the distributed and rapidly increasing volume of data and expeditious development of modern web browsers, web browsers have become a possible legitimate vehicle for remote interactive multimedia presentation and collaboration, especially for geographically dispersed teams. To our knowledge, although there are a large number of applications developed for these purposes, there are some drawbacks in prior work including the lack of interactive controls of presentation flows, general-purpose collaboration support on multimedia, and efficient and precise replay of presentations. To fill the research gaps in prior work, in this dissertation, we propose a web-based multimedia collaborative presentation document system, which models a presentation as media resources together with a stream of media events, attached to associated media objects. It represents presentation flows and collaboration actions in events, implements temporal and spatial scheduling on multimedia objects, and supports real-time interactive control of the predefined schedules. As all events are represented by simple messages with an object-prioritized approach, our platform can also support fine-grained precise replay of presentations. Hundreds of kilobytes could be enough to store the events in a collaborative presentation session for accurate replays, compared with hundreds of megabytes in screen recording tools with a pixel-based replay mechanism

    Modeling and Analysis of Power Processing Systems

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    The feasibility of formulating a methodology for the modeling and analysis of aerospace electrical power processing systems is investigated. It is shown that a digital computer may be used in an interactive mode for the design, modeling, analysis, and comparison of power processing systems

    Executable Architectures and their Application to a Geographically Distributed Air Operations Center

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    Integrated Architectures and Network Centric Warfare represent two central concepts in the Department of Defense\u27s (DoD) on-going transformation. The true power of integrated architectures is brought to bear when they are combined with simulation to move beyond a static representation and create an executable architecture. This architecture can then be used to experiment with system configurations and parameter values to guide employment decisions. The process of developing and utilizing an executable architecture will be employed to assess an Air Operations Center (AOC). This thesis applies and expands upon the methodology of Dr. Alexander Levis, former Chief Scientist of the Air Force, to the static architecture representing the Aerospace Operations Center (AOC). Using Colored Petri Nets and other simulation tools, an executable architecture for the AOC\u27s Air Tasking Order (ATO) production thread was developed. These models were then used to compare the performance of a current, forward-deployed AOC configuration to three other potential configurations that utilize a network centric environment to deploy a portion of the AOC and provide reach-back capabilities to the non-deployed units. Performance was measured by the amount of time required to execute the ATO cycle under each configuration. Communication requirements were analyzed for each configuration and stochastic delays were modeled for all transactions in which requirements could not be met due to the physical configuration of the AOC elements. All four configurations were found to exhibit statistically different behavior with regard to ATO cycle time

    The Limits of Liability in Promoting Safe Geologic Sequestration of CO2

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    Deployment of new technologies is vital to climate change policy, but it invariably poses difficult tradeoffs. Carbon capture and storage (“CCS”), which involves the capture and permanent burial of CO2 emissions, exemplifies this problem. This article provides an overview of CCS in Part I, focusing on geologic sequestration, and analyzes the scientific work on the potential for releases of CO2 and brine from sequestrian reservoirs. Part II evaluates the comparative advantages of government regulation and common law liability. Part III examines the relative efficiencies of different doctrines of common law liability when applied to likely releases from sequestrian sites. The authors propose a hybrid legal framework in Part IV that combines a traditional regulatory regime with a novel two-tiered system of liability that is calibrated to objective site characteristics.The Kay Bailey Hutchison Center for Energy, Law, and Busines

    Deploying building information modeling software on Desktop as a Service platform

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    Desktop as a Service (DaaS) is a novel cloud computing service that provides cloud-based virtual desktops on-demand to end users. The major advantage of DaaS is the capability to quickly deliver expeditious control of a full desktop environment to end users from various device platforms such as Android, iOS, MacOS or Web access from anywhere and at any time. This master thesis is a proof of concept to demonstrate the practicability to deploy the case company's graphics-intensive building information modeling software, Tekla Structures on Amazon Web Services' DaaS solution, named Amazon WorkSpaces. We investigated the whole deployment process of the software to the Amazon WorkSpaces. After clarifying the deployment process, we developed the working prototype consisting of different Amazon Web Services to automate the process. Furthermore, we implemented operational test cases for the prototype and for the Tekla Structures running on Amazon WorkSpaces to determine the feasibility of using this novel cloud service for the production purpose in the case company. In summary, Amazon WorkSpaces is a highly anticipated DaaS solution that can simplify the desktop and software delivery process to the case company's customers. The prototype developed in the thesis can automate the deployment process and launch new Amazon WorkSpaces to a sufficient extent. Moreover, the evaluation shows that the prototype can handle its automation tasks correctly based on the proposed architectural design and the Amazon WorkSpaces with Graphics hardware configuration are capable of operating Tekla Structures impeccably as in physical Windows desktops

    Investigation of a bearingless helicopter rotor concept having a composite primary structure

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    Experimental and analytical investigations were conducted to evaluate a bearingless helicopter rotor concept (CBR) made possible through the use of the specialized nonisotropic properties of composite materials. The investigation was focused on four principal areas which were expected to answer important questions regarding the feasibility of this concept. First, an examination of material properties was made to establish moduli, ultimate strength, and fatigue characteristics of unidirectional graphite/epoxy, the composite material selected for this application. The results confirmed the high bending modulus and strengths and low shear modulus expected of this material, and demonstrated fatigue properties in torsion which make this material ideally suited for the CBR application. Second, a dynamically scaled model was fabricated and tested in the low speed wind tunnel to explore the aeroelastic characteristics of the CBR and to explore various concepts relative to the method of blade pitch control. Two basic control configurations were tested, one in which pitch flap coupling could occur and another which eliminated all coupling. It was found that both systems could be operated successfully at simulated speeds of 180 knots; however, the configuration with coupling present revealed a potential for undesirable aeroelastic response. The uncoupled configuration behaved generally as a conventional hingeless rotor and was stable for all conditions tested

    Stochastic modeling of responsiveness, schedule risk and obsolescence of space systems, and implications for design choices

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    The U.S Department of Defense and the National Aeronautics and Space Administration continue to face common challenges in the development and acquisition of their space systems. In particular, space programs repeatedly experience significant schedule slippages, and spacecraft are often delivered on-orbit several months, sometimes years, after the initially planned delivery date. The repeated pattern of these schedule slippages suggests deep-seated flaws in managing spacecraft delivery and schedule risk, and an inadequate understanding of the drivers of schedule slippages. Furthermore, due to their long development time and physical inaccessibility after launch, space systems are exposed to a particular and acute risk of obsolescence, resulting in loss of value or competitive advantage over time. The perception of this particular risk has driven some government agencies to promote design choices that may ultimately be contributing to these schedule slippages, and jeopardizing what is increasingly recognized as critical, namely space responsiveness. The overall research objective of this work is twofold: (1) to identify and develop a thorough understanding of the fundamental causes of the risk of schedule slippage and obsolescence of space systems; and in so doing, (2) to guide spacecraft design choices that would result in better control of spacecraft delivery schedule and mitigate the impact of these "temporal risks" (schedule and obsolescence risks). To lay the groundwork for this thesis, first, the levers of responsiveness, or means to influence schedule slippage and impact space responsiveness are identified and analyzed, including design, organizational, and launch levers. Second, a multidisciplinary review of obsolescence is conducted, and main drivers of system obsolescence are identified. This thesis then adapts the concept of a technology portfolio from the macro- or company level to the micro-level of a single complex engineering system, and it analyzes a space system as a portfolio of technologies and instruments, each technology with its distinct stochastic maturation path and exposure to obsolescence. The selection of the spacecraft portfolio is captured by parameters such as the number of instruments, the initial technology maturity of each technology/instrument, the resulting heterogeneity of the technology maturity of the whole system, and the spacecraft design lifetime. Building on the abstraction of a spacecraft as a portfolio of technologies, this thesis then develops a stochastic framework that provides a powerful capability to simultaneously explore the impact of design decisions on spacecraft schedule, on-orbit obsolescence, and cumulative utility delivered by the spacecraft. Specifically, this thesis shows how the choice of the portfolio size and the instruments Technology Readiness Levels (TRLs) impact the Mean-Time-To-Delivery (MTTD) of the spacecraft and mitigate (or exacerbate) schedule risk. This work also demonstrates that specific combinations/choices of the spacecraft design lifetime and the TRLs can reduce the risk of on-orbit obsolescence. This thesis then advocates for a paradigm shift towards a calendar-based design mindset, in which the delivery time of the spacecraft is accounted for, as opposed to the traditional clock-based design mindset. The calendar-based paradigm is shown to lead to different design choices, which are more likely to prevent schedule slippage and/or enhance responsiveness and ultimately result in a larger cumulative utility delivered. Finally, missions scenarios are presented to illustrate how the framework and analyses here proposed can help identify system design choices that satisfy various mission objectives and constraints (temporal as well as utility-based).PhDCommittee Chair: Saleh Joseph; Committee Member: Brown Owen; Committee Member: Erwin R. Scott; Committee Member: Feron Eric; Committee Member: Mavris Dimitr
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