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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.
1

Progressive Enlightenment: The Origins of the Gaslight Industry 1780–1820

Tomory, Leslie 28 September 2009 (has links)
Gaslight, an Industrial Revolution technology, developed in the period 1780–1820. The foundations for the technology are partly found in the pneumatic chemistry of the eighteenth century, both in terms of the knowledge of gases and their properties, and the instruments used to manipulate them, such as the gasometer, making gaslight one of the earliest instances of a technology heavily based on science. Although many people experimented with lighting with gases in the late eighteenth century, the move to a commercial technology began with Philippe Lebon and William Murdock who had a clear commercial purpose in mind. The technology in its early phases was found everywhere in Europe, but it was at Boulton & Watt in Birmingham that it was first successfully applied. As Boulton & Watt developed the technology they identified many and solved some of the problems associated with scaling up the technology. They were not, however, very interested in gaslight and only sporadically gave attention to it, before effectively abandoning it around 1812. They nevertheless had an important role to play in its development not only because if their technical work, but also because they demonstrated the technology’s viability to the broad public, and by giving people experience in gas engineering. The technology's final form as a network utility was partly as a result of a battle fought between Boulton & Watt and Frederick Winsor's Gas Light and Coke Company in London during 1807–1810. Boutlon & Watt did not want a large limited-liability corporation as a competitor, and the contest in Parliament between the two groups resulted in a negotiated compromise where the Gas Light and Coke Company gave up all rights to manufacture apparatus, and focused exclusively on gas provision, effectively making it a utility. The years from 1812–1820 saw the technology mature into a large network which included not only technical development, such as the pressure balancing with valves and regulators, but also political and social elements, such as the control of user expectations through education and usage enforcement through inspectors. By 1820, the technology was sufficiently developed to be transferred to the Continent.
2

Progressive Enlightenment: The Origins of the Gaslight Industry 1780–1820

Tomory, Leslie 28 September 2009 (has links)
Gaslight, an Industrial Revolution technology, developed in the period 1780–1820. The foundations for the technology are partly found in the pneumatic chemistry of the eighteenth century, both in terms of the knowledge of gases and their properties, and the instruments used to manipulate them, such as the gasometer, making gaslight one of the earliest instances of a technology heavily based on science. Although many people experimented with lighting with gases in the late eighteenth century, the move to a commercial technology began with Philippe Lebon and William Murdock who had a clear commercial purpose in mind. The technology in its early phases was found everywhere in Europe, but it was at Boulton & Watt in Birmingham that it was first successfully applied. As Boulton & Watt developed the technology they identified many and solved some of the problems associated with scaling up the technology. They were not, however, very interested in gaslight and only sporadically gave attention to it, before effectively abandoning it around 1812. They nevertheless had an important role to play in its development not only because if their technical work, but also because they demonstrated the technology’s viability to the broad public, and by giving people experience in gas engineering. The technology's final form as a network utility was partly as a result of a battle fought between Boulton & Watt and Frederick Winsor's Gas Light and Coke Company in London during 1807–1810. Boutlon & Watt did not want a large limited-liability corporation as a competitor, and the contest in Parliament between the two groups resulted in a negotiated compromise where the Gas Light and Coke Company gave up all rights to manufacture apparatus, and focused exclusively on gas provision, effectively making it a utility. The years from 1812–1820 saw the technology mature into a large network which included not only technical development, such as the pressure balancing with valves and regulators, but also political and social elements, such as the control of user expectations through education and usage enforcement through inspectors. By 1820, the technology was sufficiently developed to be transferred to the Continent.
3

Content Distribution in Social Groups

Aggarwal, Saurabh January 2014 (has links) (PDF)
We study Social Groups consisting of self-interested inter-connected nodes looking for common content. We can observe Social Groups in various socio-technological networks, such as Cellular Network assisted Device-to-Device communications, Cloud assisted Peer-to-Peer Networks, hybrid Peer-to-Peer Content Distribution Networks and Direct Connect Networks. Each node wants to acquire a universe of segments at least cost. Nodes can either access an expensive link to the content distributor for downloading data segments, or use the well-connected low cost inter-node network for exchanging segments among themselves. Activation of an inter-node link requires cooperation among the participating nodes and reduces the cost of downloading for the nodes. However, due to uploading costs, Non-Reciprocating Nodes are reluctant to upload segments, in spite of their interest in downloading segments from others. We define the Give-and-Take (GT) criterion, which prohibits non-reciprocating behaviour in Social Groups for all nodes at all instants. In the “Full Exchange” case studied, two nodes can exchange copies of their entire segment sets, if each node gains at least one new segment from the other. Incorporating the GT criterion in the Social Group, we study the problem of downloading the universe at least cost, from the perspective of a new node having no data segments. We analyze this NP-hard problem, and propose algorithms for choosing the initial segments to be downloaded from the content distributor and the sequence of nodes for exchange. We compare the performance of these algorithms with a few existing P2P downloading strategies in terms of cost and running time. In the second problem, we attempt to reduce the load on the content distributor by choosing a schedule of inter-node link activations such that the number of nodes with the universe is maximized. Link activation decisions are taken by a central entity, the facilitator, for achieving the social optimum. We present the asymptotically optimal Randomized algorithm. We also present other algorithms, such as the Greedy Links algorithm and the Polygon algorithm, which are optimal under special scenarios of interest. We compare the performances of all proposed algorithms with the optimal value of the objective. We observe that computationally intensive algorithms exhibit better performance. Further, we consider the problem of decentralized scheduling of links. The decisions of link activations are made by the participating nodes in a distributed manner. While conforming to the GT criterion for inter-node exchanges, each node's objective is to maximize its utility. Each node tries to find a pairing partner by preferentially exploring nodes for link formation. Unpaired nodes choose to download a segment using the expensive link with Segment Aggressiveness Probability (SAP). We present linear complexity decentralized algorithms for nodes to choose their best strategy. We present a decentralized randomized algorithm that works in the absence of the facilitator and performs close to optimal for large number of nodes. We define the Price of Choice to benchmark performance of Social Groups (consisting of non-aggressive nodes) with the optimal. We evaluate the performance of various algorithms and characterize the behavioural regime that will yield best results for node and Social Group as well.

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