Browsing by Subject "Heuristic"
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Item Lot-sizing and scheduling problem with earliness and tardiness penalties(Texas Tech University, 2004-05) Supithak, WisutNot availableItem ObjectRhetoric: an object-oriented rhetoric of hypertext for technical communication(Texas Tech University, 2007-12) Jones, Roland AlexanderTechnical communication is becoming increasingly focused on the efficient production of documentation, largely commoditizing a profession based, at least in part, on the art of rhetoric. As technical communicators embrace single sourcing, the practice of writing content for one context and reusing it in others, the impetus is on technological solutions that enable more output with less effort. This dissertation will describe a new rhetoric to help technical communicators in dealing with the complexities of composing within a hypertextual and single-source based environment while employing the traditional skills of the profession. A useful model for technical communicators working with reusable content is that offered by object-orientation, a programming method that likewise focuses on reusable content, specifically program code. Rather than defining a series of algorithms in program code, which results in inefficiencies similar to those of writing and maintaining individual documents, object-orientation segregates code by creating models of interaction among code objects which then govern themselves. Such a process could help create more efficient and sustainable methods of creating documentation if applied to technical communication. Since these objects offer a new approach to authoring, a rhetoric of such objects becomes necessary before they can be implemented for technical communication. Since these objects are connected through complex referential relationships, they are also an advanced form of hypertext. Object-orientation and the hypertext theory of Ted Nelson provide language suitable for defining such a rhetoric. A theory of invention is equivalent to understanding how knowledge is formed, manipulated, and stored within the mind; cognitive theory and the work of Marvin Minsky and Roger Shank help define a suitable metaphor for this rhetoric. Lastly, elements of the process will be shown through the example of real-world activities such as those involved in complex documentation efforts.Item The Coordianted Decentralized Paratransit Sysyem: Design, Formulation, and Heuristic(2012-07-16) Shen, Chung-WeiThis dissertation investigates the different organizational structures of paratransit services that cover large regions. A paratransit service is demand-responsive, shared-ride transit service using vans or small buses. It is characterized by the use of vehicles that do not operate on a fixed route or a fixed schedule. The paratransit route and schedule are arranged from a user-specified origin to a user-specified destination, and at a user-specified time. To retain productivity by focusing on shorter trips within a denser area, some larger systems have outsourced operations to more than one contractor, with each contractor responsible for the service zone to which their vehicles have been assigned. This service design is called a "zonal structure" or a "zoning approach." The zoning with transfer system coordinates vehicles' schedules at various transfer locations. The schedule coordination of inter-zonal mechanisms of transportation likely reduces trip costs by increasing the ridesharing rate and lowering the number of empty return miles. This study first presents the exact formulation for a coordinated decentralized paratransit system in order to compare its productivity and service quality with independent decentralized and centralized strategies. The formulation is then proven to work correctly, and the results of the computational experiments of small scale instances are shown to demonstrate that the proposed coordinated system is superior to independent decentralized systems in terms of passenger miles per vehicle revenue mile. In the second section, this study develops an insertion-based heuristic method in order to compare the performances of different operational designs when applied to a large-scale system. In an experiment utilizing Houston's demand-responsive service data, we compare the productivity and service levels among three organizational structures: zoning with transfer, zoning without transfer, and no-zoning designs. The results indicate that zoning with transfer can provide significant benefits to paratransit operations that manage zoning structure; however, the no-zoning strategy used by Houston METRO (a relatively low-density region) performs better on average in terms of efficiency. This study concludes that the zoning with transfer method can be proven to be a productive organizational structure.