Thesis (Nav. E.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and, (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, 2013. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 145-146). / Internal arrangements and bulky equipment like machinery have been treated for many years as a secondary aspect of the ship design. Traditionally, in the design process, the centerpiece of the effort is the hull and its hydrodynamic performance. Once the hull of a ship has been selected, all the other systems, like propulsion and electric plants, are selected and fitted in the ship. Due to the fact that the hull is considered as the most important system of the ship, any compromises and systems trade-offs that need to be done in the design process are focused mainly on all the systems apart from the hull-form. This inherent prioritization in the traditional design process, might lead to the selection of suboptimal solutions for the other systems like the propulsion and electric plants, which in turns might lead to a global suboptimal solution for the whole ship design. Unfortunately, these decisions bound the designed ship for lifetime and, down the road, might lead to excess operational costs. The tool developed in this thesis treats the internal arrangements and the hull-form of the ship as two systems that need to be optimized together and not on a decoupled manner. Thus, the selection of the propulsion and electric plants or even large weapon systems like VLCs becomes as important as the hull during the design process. Propulsion and electric systems can be preselected in the early stage design, based on their efficiency and then a hull can be wrapped around them. The optimization of the hull can be done either with the use of the Holtrop method or a potential flow panel method, which provides higher fidelity. The designer has the ability to utilize this tool in order to easily conduct trade-off studies between the internal arrangements and the hull-form or save time from their integration and allocate it in other important problems of the design. This could aid the decision-making process in the early stage of the design, where information is scarce, decisions are crucial and uncertainty is high. / by Konstantinos Nestoras. / S.M. / Nav.E.

No description available.

Thesis (Nav. E.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and, (S.M. in Engineering and Management)--Massachusetts Institute of Technology, Engineering Systems Division, System Design and Management Program, 2011. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. [100]-102). / Although propulsion and electric power systems selection is an important part of naval ship design, respective decisions often have to be made without detailed ship knowledge (resistance, propulsors, etc.). Propulsion and electric power systems have always had to satisfy speed and ship-service power requirements. Nowadays, increasing fuel costs are moving such decisions towards more fuel-efficient solutions. Unlike commercial ships, naval ships operate in a variety of speeds and electric loads, making fuel consumption optimization challenging. This thesis develops a flexible decision support tool in Matlab® environment, which identifies the propulsion and ship-service power generation systems configuration that minimizes fuel consumption for any ship based on its operating profile. Mechanical-driven propulsion systems with or without propulsion derived ship-service power generation, separate ship-service systems and integrated power systems are analyzed. Modeling includes hull resistance using the Holtrop-Mennen method requiring only basic hull geometry information, propeller efficiencies using the Wageningen B series and transmission and prime movers fuel efficiencies. Propulsion and ship-service power generation systems configuration is optimized using the genetic algorithm. US Navy's Advanced Surface Ship Evaluation Tool (ASSET) model for the DDG-51 Flight I destroyer was used for modeling validation. Optimal fuel consumption results are compared against the existing configuration for the DDG-51 Flight I destroyer using a representative operating profile. / by Emmanouil Sarris. / S.M.in Engineering and Management / Nav.E.

<p> The discipline of systems engineering continues to increase in importance. There are more projects, projects are larger, and projects are more critical, and all of these mean that more and better systems engineering is required. It follows that the cost of systems engineering continues to increase in importance. In turn, it follows that accurate estimation of systems engineering costs continues to increase in importance, as systems engineering results suffer if a project either underestimates or overestimates its cost. </p><p> There are models for estimating systems engineering cost, notably COSYSMO 1.0, but all these models leave out some aspect of modern practices, and therefore tend to estimate a modern systems engineering cost inaccurately, or not at all. These modern practices include reuse of engineering artifacts, requirements volatility, and engineering in a system-of-systems context. While all of these practices have been addressed to some extent in research papers, there is no all-encompassing model that integrates all of them. </p><p> My research has resulted in an integrated model that includes the features of COSYSMO 1.0 and covers those modern practices. It is open and therefore widely available. I have completed a comprehensive model based, in part, on actual project data.</p><p>

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics; and, (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, 2007. / Includes bibliographical references (p. 143-154). / Product development is a major source of competitive advantage in the commercial aircraft business. Judiciously implementing commonality across a range of products yields important benefits in this area. Thus, measuring the quality of commonality implementation is extremely beneficial for aircraft manufacturers. This thesis analyses the concept of commonality and divides it into three constructs that can help understand all of its aspects: standardization, reusability and modularity. This work then presents a set of metrics measuring each of these aspects, from the point of view of the manufacturer and of the customer. The appropriateness of this set of metrics is then tested in a case study analyzing the efficiency of commonality implementation in the cockpit of two well-known commercial aircraft families: the Airbus A320 family and the Boeing 737 family. This thesis further describes what additional analysis should be performed to validate the set of metrics for broader applications. After documenting the efficiency of the set of metrics, this thesis analyses the current practices of commonality management in commercial aviation. It finally explores some of the limitations of the concept of commonality and sketches solutions to overcome them. / by Damien Bador. / S.M.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also from UMI/Dissertation Abstracts International.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references (leaves 104-112). Available also in a digital version from Dissertation Abstracts.

This work examines the belief system underlying computer-based systems development, by reference to an analogy with a model of scientific research due to Kuhn. Kuhn's model describes 'scientific communities', each united by an underlying many-faceted belief system, the 'disciplinary matrix', which forms a constellation of commitments shared by the members of these communities. A scientific community is compared here with the community of computer-based systems developers and its sub-groups. The division of the developers of computer-based systems development methods and tools into schools based on paradigmatic differences is paralleled with Kuhn's view of a scientific discipline at the early, pre-science, stage. The use of a computer-based systems development method in practice, and informal computer-based systems development activities, are paralleled with Kuhnian normal science, working within the paradigm of the discipline and of the techniques employed. This parallel provides a framework for structuring the explicit and implicit assumptions and models which form the craft knowledge underlying computer-based systems development theory and practice. Following a search for elements of the disciplinary matrix in the theory of computer-based systems development, as described in textbooks, and in its practice through interviews with developers, the results of action research and reports of systems development failures, it is concluded that the analogy with Kuhn's view of scientific activity is justifiable, and that articulation and examination of the implications of the analogy can reveal useful information to assist in describing and improving computer-based systems development. The results of this search are presented in terms of the specific beliefs and models identified. It is suggested that, as future research, the Kuhn-based model of computer-based systems development should be extended into a detailed investigation into the effects of individual elements of the disciplinary matrix, either individually or in combination, on the mind set of the computer-based systems developer.

This thesis describes the development of a computer-aided fault tree synthesis package for application in the process industries. It builds on the previous research work carried out in the Plant Engineering Group at Loughborough University. The emphasis has been put on describing the underlying methodology as opposed to the actual computer programs. The methodology described was developed by modelling a number of "real" systems, which had already been analysed using manual fault tree construction techniques by British Gas plc. Additionally a number of standard examples from the literature were utilised, as well as a large number of contrived examples to fully evaluate the package. The problems encountered and their solution are described. The culmination of this project was the implementation of the computer package at the Midlands Research Station of British Gas plc. It is not intended that the package should replace the fault tree expert. It should rather be viewed as a tool to facilitate the work of the process engineer, particularly during the design phase. This should enable the evaluation of many more options, which would otherwise have been proved prohibitive by the effort required to manually synthesise the fault trees.

Thesis (Ph.D.)--Drexel University, 2009. / Includes abstract and vita. Includes bibliographical references (leaves 112-122).