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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
631

Energy watch: an energy conservation project for elementary schools

Trusler, Bonnie R. 01 January 1994 (has links)
The goal of this project was to organize and implement an energy conservation program for second and fifth grade students that would increase their overall awareness and understanding of energy concepts and energy conservation.
632

Analýza provozních dat ze studentského centra FIT VUT v Brně / Analysis of operating data from the student centre at the Faculty of Information Technologies

Suchá, Petra January 2008 (has links)
This diploma thesis is dedicated to the analysis of operating data from the Brewery, a former industrial building, which has been reconstructed to a student centre of the Faculty of Information Technologies. The main goal of the work was to analyze the performance of the building and to evaluate energy savings originating from the energy saving measures that were applied during the retrofit.. The first part of the thesis focuses on the particular energy saving measures and the predictions of energy savings. The second part presents the results of the monitoring of the building and the HVAC systems during the first year of the operation of the Brewery.
633

Process Integration: Unifying Concepts, Industrial Applications and Software Implementation

Mann, James Gainey 29 October 1999 (has links)
This dissertation is a complete unifying approach to the fundamentals, industrial applications and software implementation of an important branch of process-engineering principles and practice, called process integration. The latter refers to the system-oriented, thermodynamically-based and integrated approaches to the analysis, synthesis and retrofit of process plants, focusing on integrating the use of materials and energy, and minimizing the generation of emissions and wastes. This work extends process integration to include applications for industrial water reuse and wastewater minimization and presents previous developments in a unified manner. The basic ideas of process integration are: (1) to consider first the big picture by looking at the entire manufacturing process as an integrated system; (2) to apply process-engineering principles to key process steps to establish a priori targets for the use of materials and energy, and for the generation of emissions and wastes; and (3) to finalize the details of the process design and retrofit later to support the integrated view, particularly in meeting the established targets. Pinch technology is a set of primarily graphical tools for analyzing a process plant's potential for energy conservation, emission reduction and waste minimization. Here, we identify targets for the minimum consumption of heating and cooling utilities, mass-separating agents, freshwater consumption, wastewater generation and effluent treatment and propose economical grassroots designs and retrofit projects to meet these goals. An emerging alternative approach to pinch technology, especially when analyzing complex water-using operations and effluent-treatment systems, is mathematical optimization. We solve nonlinear programming problems for simple water-using operations through readily available commercial software. However, more complex, nonconvex problems require sophisticated reformulation techniques to guarantee optimality and are the subject of continuing academic and commercial development. This work develops the principles and practice of an environmentally significant breakthrough of process integration, called water-pinch technology. The new technology enables the practicing engineers to maximize water reuse, reduce wastewater generation, and minimize effluent treatment through pinch technology and mathematical optimization. It applies the technology in an industrial water-reuse demonstration project in a petrochemical complex in Taiwan, increasing the average water reuse (and thus reducing the wastewater treatment) in the five manufacturing facilities from 18.6% to 37%. This dissertation presents complete conceptual and software developments to unify the known branches of process integration, such as heat and mass integration, and wastewater minimization, and explores new frontiers of applications to greatly simplify the tools of process integration for practicing engineers. / Ph. D.
634

Using Spammers' Computing Resources for Volunteer Computing

Bui, Thai Le Quy 13 March 2014 (has links)
Spammers are continually looking to circumvent counter-measures seeking to slow them down. An immense amount of time and money is currently devoted to hiding spam, but not enough is devoted to effectively preventing it. One approach for preventing spam is to force the spammer's machine to solve a computational problem of varying difficulty before granting access. The idea is that suspicious or problematic requests are given difficult problems to solve while legitimate requests are allowed through with minimal computation. Unfortunately, most systems that employ this model waste the computing resources being used, as they are directed towards solving cryptographic problems that provide no societal benefit. While systems such as reCAPTCHA and FoldIt have allowed users to contribute solutions to useful problems interactively, an analogous solution for non-interactive proof-of-work does not exist. Towards this end, this paper describes MetaCAPTCHA and reBOINC, an infrastructure for supporting useful proof-of-work that is integrated into a web spam throttling service. The infrastructure dynamically issues CAPTCHAs and proof-of-work puzzles while ensuring that malicious users solve challenging puzzles. Additionally, it provides a framework that enables the computational resources of spammers to be redirected towards meaningful research. To validate the efficacy of our approach, prototype implementations based on OpenCV and BOINC are described that demonstrate the ability to harvest spammer's resources for beneficial purposes.
635

Efficient Adoption of Residential Energy Technologies Through Improved Electric Retail Rate Design

Rauschkolb, Noah Benjamin January 2023 (has links)
This dissertation combines methods from engineering, operations research, and economics to analyze how emerging residential energy technologies can be effectively used to reduce both energy costs and carbon emissions. Our most important finding is that air-source heat pumps can be used to reduce both energy costs and carbon emissions in four out of the five major climate regions studied, but that electric retail rate reform is needed to provide customers with appropriate incentives. In cold climates, it may be advantageous to use heat pumps in tandem with fossil fuel-powered furnaces; in warmer regions, furnaces can be cost-effectively abandoned altogether. We do not find that distributed rooftop solar panels or distributed battery storage are effective tools for reducing the cost of energy services. Rather, in our simulations, customers adopt these technologies in response to poor price signaling by electric utilities. By reforming electric retail rates so that the prices paid by consumers better reflect the cost of energy services, utilities can promote the adoption of technologies that reduce both aggregate costs and carbon emissions.
636

Engaged Employees in Energy Conservation : exploring how to get there

Bedoire, Linnea, Nordling, Maria January 2023 (has links)
Energy consumption is one of the major contributors to greenhouse gas emissions and to climate change. Renewable energy sources are one way of mitigating the problem, but behavioral change and reductions in consumption are also required. In addition, little is known about how energy conservation behaviors are driven or hindered at workplaces, but it has been found in previous research that employee engagement is an important factor. Therefore, this study takes a mixed method approach utilizing the framework of Community-Based Social Marketing at a pharmaceutical manufacturing site in Sweden to investigate drivers and barriers to energy conservation, designing an intervention aiming at increasing employee engagement as well as changing behaviors, and evaluating the study using interviews, surveys and real time measurements. The findings of this study suggest that several factors act as barriers and drivers to energy conservation behaviors at work, e.g., interest, organizational culture, work processes and commitment from the company and management. The designed intervention, an inclusionary trans- disciplinary workshop, seems to have increased engagement and has preliminarily influenced pro-environmental behavior changes, as well as mitigated some barriers and strengthened some drivers.
637

Performance Evaluation of UNT Apogee Stadium Wind Turbines

McCary, William D., III 05 1900 (has links)
The following report chronicles the University of North Texas Wind Turbine Project at Apogee Stadium. The timeline of events will include the feasibility study conducted by and for the university, grant awards from the Texas State Energy Conservation Office to fund the project, and a three-year sample of real time performance data since installation. The purpose of this case study is to compare the energy generation estimates by various stakeholders to the measured energy generation using a new but uniform performance relationship. In order to optimize energy generation in wind turbine generator systems, the most common wind speeds measured at the site should also be the most efficient wind speeds at which the wind turbine can convert the kinetic energy in the wind into mechanical energy and ultimately electrical energy. The tool used to convey this relationship will be a figure plotting the wind speed profile against the efficiency curve of the wind turbine. Applying this relationship tool to the UNT Apogee Stadium wind turbines provided valuable results. The most common wind speeds at Apogee Stadium are not the most efficient wind speed for the turbine. Also, the most common wind speeds were near the lower limit of the wind turbine’s performance parameters. This scenario was evident in both the energy generation predictions as well as the real-time recorded data. This case study will also present the economic analysis of the Apogee Stadium wind turbines using another tool that was not previously used in the feasibility study. The case study concludes with future steps to improve wind turbine performance, and to budget future cost using past, present and future energy savings.
638

Momentum work and the energetic foundations of physics: I. Newton’s laws of motion tailored to processes

Kalies, Grit, Do, Duong 05 January 2024 (has links)
Modern physics is based on Newton’s laws of motion, which describe interaction via forces. In this paper, we argue that interaction needs to be described in terms of processes. By introducing the momentum work and the associated momentum energy in mechanics, we present a coherent formulation of the process equations for mechanics and thermodynamics. This naturally leads to a simple derivation of the Lorentz-transformed mass, according to which any object changes its mass in real terms when its velocity is changed. Momentum work requires a revision of Newton’s laws of motion. For the first time in the history of physics, the elastic collision between objects, such as particles, can be described as a temporal process, not as interaction via force = counter-force. The mechanism of energy conversion during the elastic collision and other mechanical processes, such as free fall, becomes clear and demonstrates the validity of the principle of energy conservation on microscale at any point in time. The results suggest that physics can be rebuilt on a more coherent footing of dynamic processes up to quantum-process thermodynamics.
639

Design and Analysis of Adaptive Fault Tolerant QoS Control Algorithms for Query Processing in Wireless Sensor Networks

Speer, Ngoc Anh Phan 02 May 2008 (has links)
Data sensing and retrieval in WSNs have a great applicability in military, environmental, medical, home and commercial applications. In query-based WSNs, a user would issue a query with QoS requirements in terms of reliability and timeliness, and expect a correct response to be returned within the deadline. Satisfying these QoS requirements requires that fault tolerance mechanisms through redundancy be used, which may cause the energy of the system to deplete quickly. This dissertation presents the design and validation of adaptive fault tolerant QoS control algorithms with the objective to achieve the desired quality of service (QoS) requirements and maximize the system lifetime in query-based WSNs. We analyze the effect of redundancy on the mean time to failure (MTTF) of query-based cluster-structured WSNs and show that an optimal redundancy level exists such that the MTTF of the system is maximized. We develop a hop-by-hop data delivery (HHDD) mechanism and an Adaptive Fault Tolerant Quality of Service Control (AFTQC) algorithm in which we utilize "source" and "path" redundancy with the goal to satisfy application QoS requirements while maximizing the lifetime of WSNs. To deal with network dynamics, we investigate proactive and reactive methods to dynamically collect channel and delay conditions to determine the optimal redundancy level at runtime. AFTQC can adapt to network dynamics that cause changes to the node density, residual energy, sensor failure probability, and radio range due to energy consumption, node failures, and change of node connectivity. Further, AFTQC can deal with software faults, concurrent query processing with distinct QoS requirements, and data aggregation. We compare our design with a baseline design without redundancy based on acknowledgement for data transmission and geographical routing for relaying packets to demonstrate the feasibility. We validate analytical results with extensive simulation studies. When given QoS requirements of queries in terms of reliability and timeliness, our AFTQC design allows optimal "source" and "path" redundancies to be identified and applied dynamically in response to network dynamics such that not only query QoS requirements are satisfied, as long as adequate resources are available, but also the lifetime of the system is prolonged. / Ph. D.
640

Dynamic Redundancy Management of Multisource Multipath Routing Integrated with Voting-based Intrusion Detection in Wireless Sensor Networks

Al-Hamadi, Hamid Helal 24 April 2014 (has links)
Wireless sensor networks (WSNs) are frequently deployed unattended and can be easily captured or compromised. Once compromised, intrusion prevention methods such as encryption can no longer provide any protection, as a compromised node is considered a legitimate node and possesses the secret key for decryption. Compromised nodes are essentially inside attackers and can perform various attacks to break the functionality of the system. Thus, for safety-critical WSNs, intrusion detection techniques must be used to detect and remove inside attackers and fault tolerance techniques must be used to tolerate inside attackers to prevent security failure. In this dissertation research, we develop a class of dynamic redundancy management algorithms for redundancy management of multisource multipath routing for fault and intrusion tolerance, and majority voting for intrusion detection, with the goal of maximizing the WSN lifetime while satisfying application quality-of-service and security requirements, for base station based WSNs, homogeneous clustered WSNs, and heterogeneous clustered WSNs. By means of a novel model-based analysis methodology based on probability theory, we model the tradeoff between energy consumption vs. reliability, timeliness and security gain, and identify the optimal multisource multipath redundancy level and intrusion detection settings for maximizing the lifetime of the WSN while satisfying application quality-of-service requirements. A main contribution of our research dissertation is that our dynamic redundancy management protocol design addresses the issues of "how many paths to use" and "what paths to use" in multisource multipath routing for intrusion tolerance. Another contribution is that we take an integrated approach combining intrusion detection and tolerance in the protocol design to address the issue of "how much intrusion detection is enough" to prevent security failure and prolong the WSN lifetime time. We demonstrate resiliency of our dynamic redundancy management protocol design for intrusion detection and tolerance against sophisticated attacker behaviors, including selective and random capture, as well as persistent, random, opportunistic and insidious attacks, by model-based performance analysis with results supported by extensive simulation based on ns3. / Ph. D.

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