Genetic Stereo Matching Algorithm with Fuzzy Fitness

This paper presents a genetic stereo matching algorithm with fuzzy evaluation function. The proposed algorithm presents a new encoding scheme in which a chromosome is represented by a disparity matrix. Evolution is controlled by a fuzzy fitness function able to deal with noise and uncertain camera measurements, and uses classical evolutionary operators. The result of the algorithm is accurate dense disparity maps obtained in a reasonable computational time suitable for real-time applications as shown in experimental results

Kuadratik görüntü filtrelerinin hızlandırılmış eğitimi için GPU tabanlı yeni bir algoritma tasarımı

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Kuadratik görüntü filtreleri, doğrusal olmayan gürültü karakteristiklerini ele almada genellikle doğrusal filtrelere göre daha başarılıdır. Ancak, ikinci dereceden filtrelerin başarısı için uygun ağırlıkların belirlenmesi, doğrusal filtrelere ağırlıklarının belirlenmesi gibi kolay değildir. Bununla birlikte referans ve gürültülü görüntülerin bulunduğu durumlarda filtre ağırlıkları optimizasyon yöntemleri ile belirlenebilir. Sezgisel algoritmalar kullanılarak ağırlıkların belirlenmesi için, referans görüntü ile filtrelenmiş görüntüye dayanan bir uygunluk değeri (Fitness Value) hesaplanması gerekir. Hesaplanan bu uygunluk değerine göre maske ağırlıkları güncellenmektedir. Bu durum durdurma kriterine kadar yinelemeli olarak tekrarlanır ve maske ağırlıklarının uygun değerleri hesaplanır. Bu süreçler çarpma işlemleri yoğun olan Kuadratik filtrelerde çok zaman almaktadır. Bu tez çalışması kapsamında Kuadratik görüntü filtrelerinin maske eğitimlerini hızlandırmak için algoritmik hızlandırma, donanımsal hızlandırma ve bunların birlikte kullanıldığı yöntemler geliştirilmiştir. Kuadratik görüntü filtrelerin maske ağırlıklarının belirlenmesi için literatürde sıklıkla başvurulan sezgisel algoritmalardan, GA (Genetik Algoritmalar) ve PSO (Parçacık Sürü Optimizasyon) Algoritmaları kullanılmıştır. Deneysel çalışmalarda, referans görüntü üzerine Gaussian gürültüsü eklenerek gürültülü test görüntüleri elde edilmiştir. Uygunluk değeri, referans görüntü ve filtrelenmiş görüntü kullanılarak belirlenen hata fonksiyonundan hesaplanmıştır. Yapılan deneysel çalışmalardan elde edilen sonuçlara göre hem algoritmik hem de donanımsal hızlandırma için önerilen yöntemlerin eğitim sürelerini kısaltmada başarılı olduğu görülmüştür. Elde edilen karşılaştırmalı sayısal sonuçlara göre, GPU hızlandırma ile birlikte kullanılan algoritmik hızlandırmada eğitim süreleri ortalama 300 kat daha fazla kısalmıştır. Ayrıca görüntü kaliteleri de sıralı gerçekleştirme ile elde edilen görüntü kalitelerine benzer oranda elde edilmiştir.Quadratic image filters are usually more successful than linear filters in handling nonlinear noise characteristics. However, determining the appropriate weights for the success of the second order filters is not as straightforward as determining the weights of the linear filters. On the other hand, when there are reference and noisy images, the filter weights can be determined by optimization methods. To determine the weights using heuristic algorithms, a fitness value based on the reference image and the filtered image must be calculated. The mask weights are updated according to this calculated fitness value. This is iteratively repeated until the stopping criterion and the appropriate values of the mask weights are calculated. These processes take a lot of time in Quadratic filters, which are intensive processes of multiplication. Within the scope of this thesis, algorithmic acceleration, hardware acceleration and methods used together to develop mask training of quadratic image filters have been developed. GA (Genetic Algorithms) and PSO (Particle Swarm Optimization) Algorithms have been used for the heuristic algorithms frequently used in the literature for determining mask weights of quadratic image filters. In experimental studies, noisy test images were obtained by adding a Gaussian noise to the reference image. The fitness value is calculated from the error function determined using the reference image and the filtered image. According to the results obtained from the experimental studies, it is seen that the methods proposed for both algorithmic and hardware acceleration are successful in shortening the training periods. According to the comparative numerical results obtained, the training times were shortened by an average of 300 times in the algorithmic acceleration used with GPU acceleration. In addition, image qualities are similar to those obtained by sequential realization

Model based test suite minimization using metaheuristics

Software testing is one of the most widely used methods for quality assurance and fault detection purposes. However, it is one of the most expensive, tedious and time consuming activities in software development life cycle. Code-based and specification-based testing has been going on for almost four decades. Model-based testing (MBT) is a relatively new approach to software testing where the software models as opposed to other artifacts (i.e. source code) are used as primary source of test cases. Models are simplified representation of a software system and are cheaper to execute than the original or deployed system. The main objective of the research presented in this thesis is the development of a framework for improving the efficiency and effectiveness of test suites generated from UML models. It focuses on three activities: transformation of Activity Diagram (AD) model into Colored Petri Net (CPN) model, generation and evaluation of AD based test suite and optimization of AD based test suite. Unified Modeling Language (UML) is a de facto standard for software system analysis and design. UML models can be categorized into structural and behavioral models. AD is a behavioral type of UML model and since major revision in UML version 2.x it has a new Petri Nets like semantics. It has wide application scope including embedded, workflow and web-service systems. For this reason this thesis concentrates on AD models. Informal semantics of UML generally and AD specially is a major challenge in the development of UML based verification and validation tools. One solution to this challenge is transforming a UML model into an executable formal model. In the thesis, a three step transformation methodology is proposed for resolving ambiguities in an AD model and then transforming it into a CPN representation which is a well known formal language with extensive tool support. Test case generation is one of the most critical and labor intensive activities in testing processes. The flow oriented semantic of AD suits modeling both sequential and concurrent systems. The thesis presented a novel technique to generate test cases from AD using a stochastic algorithm. In order to determine if the generated test suite is adequate, two test suite adequacy analysis techniques based on structural coverage and mutation have been proposed. In terms of structural coverage, two separate coverage criteria are also proposed to evaluate the adequacy of the test suite from both perspectives, sequential and concurrent. Mutation analysis is a fault-based technique to determine if the test suite is adequate for detecting particular types of faults. Four categories of mutation operators are defined to seed specific faults into the mutant model. Another focus of thesis is to improve the test suite efficiency without compromising its effectiveness. One way of achieving this is identifying and removing the redundant test cases. It has been shown that the test suite minimization by removing redundant test cases is a combinatorial optimization problem. An evolutionary computation based test suite minimization technique is developed to address the test suite minimization problem and its performance is empirically compared with other well known heuristic algorithms. Additionally, statistical analysis is performed to characterize the fitness landscape of test suite minimization problems. The proposed test suite minimization solution is extended to include multi-objective minimization. As the redundancy is contextual, different criteria and their combination can significantly change the solution test suite. Therefore, the last part of the thesis describes an investigation into multi-objective test suite minimization and optimization algorithms. The proposed framework is demonstrated and evaluated using prototype tools and case study models. Empirical results have shown that the techniques developed within the framework are effective in model based test suite generation and optimizatio