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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.
11

Modelling multivariate interval-censored and left-truncated survival data using proportional hazards model

Cheung, Tak-lun, Alan, 張德麟 January 2003 (has links)
published_or_final_version / abstract / toc / Statistics and Actuarial Science / Master / Master of Philosophy
12

Failure and Workspace Analysis of Parallel Robot Manipulators

Nazari, VAHID 10 March 2014 (has links)
A failure recovery methodology based on decomposing the platform task space into the major and secondary subtasks is proposed which enables the manipulator to minimize the least-squares error of the major subtasks and to optimize the secondary criterion. A methodology for wrench recovery of parallel manipulators is proposed so that the platform task is divided into the recoverable and non-recoverable subtasks based on the number and type of actuator failures, manipulator configuration and task/application purposes. It is investigated that when the Jacobian matrix of the manipulator is of full row-rank and the minimum 2-norm of the joint velocity vector satisfies the velocity limits of the joints, the full recovery of the platform twist will be provided. If the full recovery of the platform twist cannot be achieved, the optimization method followed by the partitioned Jacobian matrix is used to deal with the failure recovery. It is verified that the optimization method recovers as many as possible components of the platform velocity vector when the objective function, 2-norm of the overall velocity vector of the healthy joints, is minimized. To model uncertainty in the kinematic parameters, the interval analysis is proposed. Different interval-based algorithms to enclose the solution set to the interval linear systems are applied and the solution sets are compared. A novel approach in characterizing the exact solution of the interval linear system is proposed to deal with the failure recovery of parallel manipulators with velocity limits of the joints and uncertainty in the kinematic parameters. Simulation results show how the solution sets of the joint velocity vector are characterized by introducing uncertainties in the kinematic parameters. The calculation of the exact solution takes more computation time compared to the interval-based algorithms. However, the interval-based algorithms give the wider solution box with less computation time. The effect of variations and/or uncertainties in design parameters on the workspace of wire-actuated parallel manipulators without and with gravity is investigated. Simulation results show how the workspace size and shape are changed under variations in design parameters. / Thesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2014-03-09 16:18:12.74
13

Rigorous and reasonable error bounds for the numerical solution of dynamical systems

Kuhn, Wolfgang 12 1900 (has links)
No description available.
14

Robust Mechanism synthesis with random and interval variables

Venigella, Pavan Kumar, January 2007 (has links) (PDF)
Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed March 27, 2008) Includes bibliographical references (p. 86-89).
15

Nondeterministic linear static finite element analysis an interval approach /

Zhang, Hao. January 2005 (has links)
Thesis (Ph. D.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2006. / White, Donald, Committee Member ; Will, Kenneth, Committee Member ; Zureick, Abdul Hamid, Committee Member ; Hodges, Dewey, Committee Member ; Muhanna, Rafi, Committee Chair ; Haj-Ali, Rami, Committee Member.
16

Guaranteed error bounds for computed solutions of nonlinear two-point boundary value problems

Talbot, Thomas D. January 1968 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. Description based on print version record. Includes bibliographical references (p. 185-187).
17

Εκπαιδευτικό λογισμικό για την ανάλυση διαστημάτων

Γκανά, Αλεξάνδρα 11 January 2010 (has links)
Η διπλωματική εργασία αυτή,ασχολείται με τη δημιουργία ενός διδακτικού πακέτου που θα χρησιμοποιείται για τη διδασκαλία του μαθήματος "Ανάλυση Διαστημάτων" από απόσταση. Σκοπός του είναι η αξιοποίησή του από τον φοιτητή για περαιτέρω εξάσκηση στο σπίτι και για εμπέδωση των όσων διδάχθηκε στην τάξη. Πριλαμβάνει συνοπτική θεωρία στα πλαίσια του μαθήματος που διδάσκεται σε προπτυχιακό επίπεδο στο τμήμα Μαθηματικών του Παν/μιου Πατρών καθώς και παραδείγματα συνδεδεμένα άμεσα με τη θεωρία που έχει διδαχθεί. Υπάρχει σύνδεση κάθε παραγράφου της θεωρίας με τα αντίστοιχα παραδείγματα, τα οποία είναι σε μορφή video. Υλοποιούνται όλες οι μέθοδοι που αναφέρονται στο βιβλίο και υπάρχει γραφική απεικόνιση κάθε βήματος του αλγορίθμου τους και ηχητική επεξήγηση αυτών, με σκοπό την καλύτερη κατανόησή τους. Μέσα στο πακέτο υπάρχουν και ασκήσεις πολλαπλής επιλογής, αντιστοίχησης και σταυρόλεξο, όπου είτε θα μπορεί ο αναγνώστης φοιτητής να ασχοληθεί μόνος του στο σπίτι, είτε να αξιοποιηθούν από τον διδάσκοντα με τη χρήση μηχανής προβολής για εξάσκηση στην τάξη. / This diplomatic essay is related to the creation of a teaching package which will be used in the teaching process of "Interval Analysis" through distant learning. Its aim is to be fully used by the student for further practice at home and to consolidate everything they have been taught within the classroom. More analytically, it includes concise theory of the subject framework whivh is taught in Mathematics Department of Patra University in the Bachelor's level. It also includes examples directly connected to the already taught theory. Specifically, there is a connection of each theory paragraph to the corresponding examples which exist in the form of a video clip. In addition, every method mentioned in the book is accomplished and there is a graph of every step in their algprithm as well as sound effect explanation in order to their being better understood. This package includes multiple choice exercises, mathing exercises and a crossword puzzle with which the student reader will be able either to be busy with at home or the teacher will be able to fully used them with the use of a projector for practice in classroom.
18

The use of multistaic radar in reducing the impact of wind farm on civilian radar system

Al Mashhadani, Waleed January 2017 (has links)
The effects of wind farm installation on the conventional monostatic radar operation have been investigated in previous studies. The interference on radar operation is due to the complex scattering characteristics from the wind turbine structure. This research considers alternative approach for studying and potentially mitigating these negative impacts by adapting the multistatic radar system technique. This radar principle is well known and it is attracting research interest recently, but has not been applied in modelling the wind farm interference on multistatic radar detection and tracking of multiple targets. The research proposes two areas of novelties. The first area includes the simulation tool development of multistatic radar operation near a wind farm environment. The second area includes the adaptation of Range-Only target detection approach based on mathematical and/or statistical methods for target detection and tracking, such as Interval Analysis and Particle Filter. These methods have not been applied against such complex detection scenario of large number of targets within a wind farm environment. Range-Only target detection approach is often considered to achieve flexibility in design and reduction in cost and complexity of the radar system. However, this approach may require advanced signal processing techniques to effectively associate measurements from multiple sensors to estimate targets positions. This issue proved to be more challenging for the complex detection environment of a wind farm due to the increase in number of measurements from the complex radar scattering of each turbine. The research conducts a comparison between Interval Analysis and Particle Filter. The comparison is based on the performance of the two methods according to three aspects; number of real targets detected, number of ghost targets detected and the accuracy of the estimated detections. Different detection scenarios are considered for this comparison, such as single target detection, wind farm detection, and ultimately multiple targets at various elevations within a wind farm environment.
19

Rigorous Simulation : Its Theory and Applications

Duracz, Adam January 2016 (has links)
Designing Cyber-Physical Systems is hard. Physical testing can be slow, expensive and dangerous. Furthermore computational components make testing all possible behavior unfeasible. Model-based design mitigates these issues by making it possible to iterate over a design much faster. Traditional simulation tools can produce useful results, but their results are traditionally approximations that make it impossible to distinguish a useful simulation from one dominated by numerical error. Verification tools require skills in formal specification and a priori understanding of the particular dynamical system being studied. This thesis presents rigorous simulation, an approach to simulation that uses validated numerics to produce results that quantify and bound all approximation errors accumulated during simulation. This makes it possible for the user to objectively and reliably distinguish accurate simulations from ones that do not provide enough information to be useful. Explicitly quantifying the error in the output has the side-effect of leading to a tool for dealing with inputs that come with quantified uncertainty. We formalize the approach as an operational semantics for a core subset of the domain-specific language Acumen. The operational semantics is extended to a larger subset through a translation. Preliminary results toward proving the soundness of the operational semantics with respect to a denotational semantics are presented. A modeling environment with a rigorous simulator based on the operational semantics is described. The implementation is portable, and its source code is freely available. The accuracy of the simulator on different kinds of systems is explored through a set of benchmark models that exercise different aspects of a rigorous simulator. A case study from the automotive domain is used to evaluate the applicability of the simulator and its modeling language. In the case study, the simulator is used to compute rigorous bounds on the output of a model.
20

Přeurčené soustavy intervalových lineárních rovnic / Overdetermined systems of interval linear equations

Horáček, Jaroslav January 2011 (has links)
This work is focused on overdetermined systems of interval linear equati- ons. First part consists of introduction to interval arithmetics and interval linear algebra and basic theory of interval linear systems. In the second part various methods for solving overdetermined interval linear systems are de- scribed. By solution of overdetermined interval system we mean union of all solutions of all subsystems. Known and our variants of algorithms are discussed. We introduce our subsquare method. All mentioned methods are implemented in one toolbox for Matlab. Methods are tested on solvable and unsolvable overdetermined systems. For solvable systems we test solution enclosure, time and special features of methods. For unsolvable systems we test detection of unsolvability. At the end of this work we provide basic in- troduction to Intlab. 1

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