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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

Integer programming-based decomposition approaches for solving machine scheduling problems

Sadykov, Ruslan 26 June 2006 (has links)
The aim in this thesis is to develop efficient enumeration algorithms to solve certain strongly NP-hard scheduling problems. These algorithms were developed using a combination of ideas from Integer Programming, Constraint Programming and Scheduling Theory. In order to combine different techniques in one algorithm, decomposition methods are applied. The main idea on which the first part of our results is based is to separate the optimality and feasibility components of the problem and let different methods tackle these components. Then IP is ``responsible' for optimization, whereas specific combinatorial algorithms tackle the feasibility aspect. Branch-and-cut and branch-and-price algorithms based on this idea are proposed to solve the single-machine and multi-machine variants of the scheduling problem to minimize the sum of the weights of late jobs. Experimental research shows that the algorithms proposed outperform other algorithms available in the literature. Also, it is shown that these algorithms can be used, after some modification, to solve the problem of minimizing the maximum tardiness on unrelated machines. The second part of the thesis deals with the one-machine scheduling problem to minimize the weighted total tardiness. To tackle this problem, the idea of a partition of the time horizon into intervals is used. A particularity of this approach is that we exploit the structure of the problem to partition the time horizon. This particularity allowed us to propose two new Mixed Integer Programming formulations for the problem. The first one is a compact formulation and can be used to solve the problem using a standard MIP solver. The second formulation can be used to derive lower bounds on the value of the optimal solution of the problem. These lower bounds are of a good quality, and they can be obtained relatively fast.
2

Efficient Fpga Implementation Of Image Enhancement Using Video Streams

Gunay, Hazan 01 January 2010 (has links) (PDF)
This thesis is composed of three main parts / displaying an analog composite video input by via converting to digital VGA format, license plate localization on a video image and image enhancement on FPGA. Analog composite video input, either PAL or NTSC is decoded on a video decoder board / then on FPGA, video data is converted from 4:2:2 YCbCr format to RGB. To display RGB data on the screen, line doubling de-interlacing algorithm is used since it is efficient considering computational complexity and timing. When taking timing efficiency into account, image enhancement is applied only to beneficial part of the image. In this thesis work, beneficial part of the image is considered as numbered plates. Before image enhancement process, the location of the plate on the image must be found. In order to find the location of plate, a successful method, edge finding is used. It is based on the idea that the plate is found on the rows, where the brightness variation is largest. Because of its fast execution, band-pass filtering with finite response (FIR) is used for highlighting the high contrast areas. Image enhancement with rank order filter method is chosen to remove the noise on the image. Median filter, a rank order filter, is designed and simulated. To improve image quality while reducing the process time, the filter is applied only to the part of the image where the plate is. Design and simulation is done using hardware design language VHDL. Implementations of the chosen approaches are done on MATLAB and Xilinx Virtex-2 Pro FPGA. Improvement of the implementation considering speed and area is evaluated.

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