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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.
31

Cost Estimation Of Housing Projects By Functional Areas

Oncul, Mustafa 01 January 2006 (has links) (PDF)
Good conceptual cost estimates is one of the most important factors affecting the project success. Investment decisions taken and budget preparations are performed from the results of the conceptual estimates. Also, the most difficult cost estimation is the early estimates where there is very limited information. This thesis provides a model for the cost estimation of the housing projects at the conceptual stage, considering not only the total area of the construction, but also considering fractional areas, as kitchen area, bathroom area, living room area and etc. Moreover, model outputs a range of costs considering quality of the construction instead of a point estimate which allows investors to see the possible costs of the project by their choice of luxury.
32

Development of interactive aircraft design software for use in problem based learning

Al-Shamma, Omran January 2013 (has links)
In the last ten years or so, many interactive aircraft design software packages have been released into the market. One drawback of these packages is that they assume prior knowledge in the field of aircraft design. Also, their main purpose being the preliminary aircraft design in a commercial environment, and are not intended for instructional use. Aircraft Design is an iterative process, and the students in the formative years of training must realise that one year of study is not enough to embrace all the necessary underlying concepts in this field. Most universities present the aircraft design as a classical Problem-Based Learning scenario, where students work in groups, with the group size varying between 5 and 8 students., each with a designated role, to carry out a specific task. The students work through the classical process of preliminary design based largely on textbook methods. Therefore, the need for a preliminary design tool (software) that helps the students to understand, analyse, and evaluate their aircraft design process exists. The developed software does everything that is needed in the preliminary design environment. Students are interactively guided through the design process, in a manner that facilitates lifelong learning. Comprehensive output is provided to highlight the “what if scenarios”. The software consists of many modules such as input (user interface), weight estimation, flight performance, cost estimation, take-off analysis, parametric studies, optimisation, and dynamic stability. Due to the large number of input design variables, a full interactive Graphical-User-Interface (GUI) is developed to enable students to evaluate their designs quickly. Object-Oriented-Programming (OOP) is used to create the GUI environment. The stability and control derivatives computed in this work are largely based on analytical techniques. However, a facility is provided in the software to create the data input file required to run a software package produced by USAF, called DATCOM, that enables computation of the dynamic stability and control derivatives that can be ultimately used in flight simulation work. Amongst all the variables used in aircraft design, aircraft weight is the most significant. A new weight estimation module has been developed to increase the accuracy of estimation to better than 5%. Its output results agree very favourably with the published data of current commercial aircraft such as Airbus and Boeing. Also, a new formula is proposed to estimate the engine weight based on its thrust in the absence of the data available with high degree of accuracy. In order to evaluate the effectiveness of the design under consideration, a comprehensive methodology has been developed that can predict the aircraft price as a function of aircraft weight. The Direct Operating Cost (DOC) is also calculated using methods proposed by ATA, NASA, and AEA. Finally, a walk-through of two case studies are presented, one for large transport aircraft and other for small business jet, to show how typical undergraduate students will proceed with the design and to demonstrate the effectiveness of the developed software.
33

Estimating Internet-scale Quality of Service Parameters for VoIP

Niemelä, Markus January 2016 (has links)
With the rising popularity of Voice over IP (VoIP) services, understanding the effects of a global network on Quality of Service is critical for the providers of VoIP applications. This thesis builds on a model that analyzes the round trip time, packet delay jitter, and packet loss between endpoints on an Autonomous System (AS) level, extending it by mapping AS pairs onto an Internet topology. This model is used to produce a mean opinion score estimate. The mapping is introduced to reduce the size of the problem in order to improve computation times and improve accuracy of estimates. The results of testing show that estimating mean opinion score from this model is not desirable. It also shows that the path mapping does not affect accuracy, but does improve computation times as the input data grows in volume.
34

Economic aspects of additive manufacturing : benefits, costs and energy consumption

Baumers, Martin January 2012 (has links)
Additive Manufacturing (AM) refers to the use of a group of technologies capable of combining material layer-by-layer to manufacture geometrically complex products in a single digitally controlled process step, entirely without moulds, dies or other tooling. AM is a parallel manufacturing approach, allowing the contemporaneous production of multiple, potentially unrelated, components or products. This thesis contributes to the understanding of the economic aspects of additive technology usage through an analysis of the effect of AM s parallel nature on economic and environmental performance measurement. Further, this work assesses AM s ability to efficiently create complex components or products. To do so, this thesis applies a methodology for the quantitative analysis of the shape complexity of AM output. Moreover, this thesis develops and applies a methodology for the combined estimation of build time, process energy flows and financial costs. A key challenge met by this estimation technique is that results are derived on the basis of technically efficient AM operation. Results indicate that, at least for the technology variant Electron Beam Melting, shape complexity may be realised at zero marginal energy consumption and cost. Further, the combined estimator of build time, energy consumption and cost suggests t AM process efficiency is independent of production volume. Rather, this thesis argues that the key to efficient AM operation lies in the user s ability to exhaust the available build space.
35

A cost-benefit forecasting framework for assessment of advanced manufacturing technology development

Jones, Mark Benjamin January 2014 (has links)
Development of new Advanced Manufacturing Technology (AMT) for the aerospace industry is critical to enhance the manufacture and assembly of aerospace products. These novel AMTs require high development cost, specialist resource capabilities, have long development periods, high technological risks and lengthy payback durations. This forms an industry reluctance to fund the initial AMT development stages, impacting on their success within an ever increasingly competitive environment. Selection of suitable AMTs for development is typically performed by managers who make little reference to estimating the non-recurring development effort in resources and hardware cost. In addition, the performance at the conceptual stage is predicted using expert opinion, consisting of subjective and inaccurate outputs. AMTs selected are then submerged into development research and heavily invested in, with incorrect selections having a detrimental impact on the business. A detailed study of the UK aerospace manufacturing industry corroborated these findings and revealed a requirement for a new process map to resolve the problem of managing AMT developments at the conceptual stages. This process map defined the final research protocol, forming the requirement for a Cost-Benefit Forecasting Framework. The framework improves the decision making process to select the most suitable AMTs for development, from concept to full scale demonstration. Cost is the first element and is capable of estimating the AMT development effort in person-hours and cost of hardware using two parametric cost models. Benefit is the second element and forecasts the AMT tangible and intangible performance. The framework plots these quantified cost-benefit parameters and is capable of presenting development value advice for a diverse range of AMTs with varied applications. A detailed case study is presented evaluating a total of 23 novel aerospace AMTs verifying the capability and high accuracy of the framework within a large aerospace manufacturing organisation. Further validation is provided by quantifying the responses from 10 AMT development experts, after utilising the methodology within an industrial setting. The results show that quantifying the cost-benefit parameters provides manufacturing research and technology with the ability to select AMTs that provide the best value to a business.
36

The representation of an advanced service delivered by a product service system : a qualitative model of avionics availability

Thenent, Nils Elias January 2014 (has links)
The research presented in this thesis demonstrates the qualitative modelling of an advanced service delivered by a Product Service System (PSS) through the use of a socio-technical systems-based approach. The created model represents dependencies between functions and organisations, and can be used as basis for a quantitative cost model. Focus is on how one particular example of advanced services, namely availability is delivered in an industrial context. Following a review of multi-disciplinary literature and the outline of a suitable methodological approach, a detailed case study of the delivery of an exemplar piece of avionics equipment by BAE Systems and GE Aviation to the UK Royal Air Force is described. This research shows that the delivery of avionics availability through a PSS has organisational, contractual and functional facets that overlap and influence each other. Multiple qualitative models represent the investigated setting, from a functional and from an organisational perspective. Top-level functions ‘Analysis & Optimisation’, ‘Administration’ and ‘Delivery’ are identified. The results show distinctive similarities and differences between GE Aviation and BAE Systems including a variety of parallel contracts, organisational segmentation and tensions between relationships and contractual obligations. The findings suggest that understanding a PSS as a socio-technical system is crucial for modelling the PSS and the cost associated with it. This is particularly important when the aim is to continuously control and manage costs rather than the creation of a one-off forecast. The contribution of this work to the existing body of knowledge, primarily within the domain of cost engineering is twofold: First the creation of qualitative models of an existing PSS delivering avionics availability to show “what is a PSS”, and second a methodologically robust approach that takes into account the sociotechnical character of PSS to demonstrate “how to know about PSS”.
37

Cost Based Design Optimization of a Laminated Plate

Beltempo, Christopher André 24 February 2009 (has links)
The focus of this thesis is to introduce a proof-of-concept illustrating the integration of cost and performance as primary design drivers for structural design. Of particular interest to the aerospace industry is laminated structural design, therefore an example problem of a laminated plate structure is selected. This problem presents two primary challenges: linking cost in as general a way as possible to the design variables, and dealing with the many discrete design options available in a laminated plate. The first issue is examined by using a theoretical cost model for advanced composite fabrication and using a Direct Operating Cost model. The second issue is addressed using a gradient based optimization algorithm and a Discrete Material Optimization (DMO) method, which is typically used in topology optimization of structures.
38

Cost Based Design Optimization of a Laminated Plate

Beltempo, Christopher André 24 February 2009 (has links)
The focus of this thesis is to introduce a proof-of-concept illustrating the integration of cost and performance as primary design drivers for structural design. Of particular interest to the aerospace industry is laminated structural design, therefore an example problem of a laminated plate structure is selected. This problem presents two primary challenges: linking cost in as general a way as possible to the design variables, and dealing with the many discrete design options available in a laminated plate. The first issue is examined by using a theoretical cost model for advanced composite fabrication and using a Direct Operating Cost model. The second issue is addressed using a gradient based optimization algorithm and a Discrete Material Optimization (DMO) method, which is typically used in topology optimization of structures.
39

Empirical Study of MacroBIM and Conceptual Estimation

Gajbhiye, Anand Dhanraj 2010 May 1900 (has links)
Building Information Modeling (BIM) has set up a mark in the construction industry over a decade. In order to gain benefit of BIM in estimating the project cost at the early stage of construction with the limited data available, a new concept of MacroBIM has been introduced in the industry. However, limited amount of research has been implemented to determine how MacroBIM has been accepted in the construction industry. Most research was focused on the accuracy of the conceptual estimation. This research attempted to determine the effectiveness of MacroBIM process applied at early stages of construction for conceptual cost estimation. Experts from the discipline of architecture, contractor and owners were interviewed and their professional opinions on MacroBIM were analyzed using grounded theory. The results show that, compared to the traditional conceptual estimating process, MacroBIM is an effective method for 1) saving labor hours, 2) conveying assumptions with the help of its visualization capabilities, 3) enhancing the collaboration among the project participants, and 4) evaluating multiple design scenarios. However, fear of using MacroBIM and trust in its outcome existed among some contractors, architects, and owners because this technology has not matured yet. Moreover, the need of interoperability between the MacroBIM tools and MicroBIM tools, such as Revit, has also surfaced in the study.
40

Estimation Of Time-dependent Link Costs Using Gps Track Data

Unsal, Ahmet Dundar 01 December 2006 (has links) (PDF)
Intelligent Transport Systems (ITS) are becoming a part of our daily lives in various forms of application. Their success depends highly on the accuracy of the digital data they use. In networks where characteristics change by time, time-based network analysis algorithms provide results that are more accurate. However, these analyses require time-based travel speed data to provide accurate results. Conventionally, traffic data are usually obtained using the data provided from loop-detectors. These detectors usually exist on main arteries, freeways and highways / they rarely exist on back roads, secondary roads and streets due to their deployment costs. Today, telematics systems offer fleet operators to track their fleet remotely from a central system. Those systems provide data about the behaviors of vehicles with time information. Therefore, a tracking system can be used as an alternative to detector-based systems on estimating travel speeds on networks. This study aims to provide methods to estimate network characteristics using the data collected directly from fleets consisting of global positioning system (GPS) receiver equipped vehicles. GIS technology is used to process the collected GPS data spatially to match digital road maps. After matching, time-dependent characteristics of roads on which tracked vehicles traveled are estimated. This estimation provides data to perform a time-dependent network analysis. The methods proposed in this study are tested on traffic network of Middle East Technical University campus. The results showed that the proposed methods are capable of measuring time-dependent link-travel times on the network. Peak hours through the network are clearly detected.

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