Computer Science in Progress

Home   Artificial Intell.   Bio-exact   Chemistry   Computer Sci. BSc   Earth Sciences   Mathematics   Physics & Astr.   Science Educ.   Submit   Webmaster        


Displaying theses 1-10 of 310 total
Previous  1  2  3  4  5  6  7  8  9  10  11  Next  Search:

N. Motamed
Bachelor programme: Informatica August 24th, 2018
Institute: Informatics Institute Research group: Computational Science Graduation thesis Supervisor: Mike Lees
photo of the author
A Performance Analysis of Filtering Methods Applied to WiFi-based Position Reconstruction
WiFi-based position reconstruction is becoming an increasingly important field of study, with applications in both ubiquitous computing and crowd analysis. Many approaches to this problem provide high accuracy at the cost of low ease of use, by often requiring either specialised hardware of costly offline phases. We compare and analyze the use of several filtering methods in order to increase the accuracy of a low-cost and out-of-the-box trilateration approach to WiFi-based position reconstruction, by applying the filtering methods to positions reconstructed from walks through the largest stadium in the Netherlands. The compared filtering methods consist of exponential filtering, Gaussian filters, Savitzky-Golay filters, median filters and Kalman filters, along with several variations. In addition to the performance comparison, we apply sensitivity analysis to the parameters of the methods, determining which are of most importance to resulting accuracy. We find that the median filter and some of its variations perform the best, improving upon the baseline accuracy by seven metres. Other high performers include the Gaussian and Savitzky-Golay filters, which like the median filter, are simple in their procedures and require few parameters.
picture that illustrates the research done
Scientific abstract (pdf 1K)   Full text (pdf 6317K)

J. Bouman
Bachelor programme: Informatica August 10th, 2018
Institute: UvA / Other Research group: UvA / Other Graduation thesis Supervisor: dr. Zhiming Zhao
Characterizing access patterns from ftp logs
Research infrastructures provide data and other necessary services required by domain scientists for performing advanced research. The performance of the research infrastructure is crucial for the user experience. By analysing the access patterns in the log files data infrastructure operators can improve the quality of the offered end product. This study focuses on the access log files obtained from the file server of the Euro-Argo research infrastructure. Based on the operational history contained in the log files we evaluate how these usage patterns can be used to improve the offered service level to the users of the data infrastructure. We introduce a prediction based model that can forecast the future workload by exploiting the usage patterns extracted from the log files. This model makes it possible to allocate resources in advance leading to a more efficient and optimised data infrastructure improving the service level.
picture that illustrates the research done
Scientific abstract (pdf 2K)   Full text (pdf 749K)

K.W. Chung
Bachelor programme: Informatica July 13th, 2018
Institute: Informatics Institute Research group: Lecturer's Group Graduation thesis Supervisor: Robert Belleman
Short-lasting effects of Redirected Walking in Virtual Reality
This thesis takes a look at the effects that "Redirected Walking might have on users' ability to orientate.
picture that illustrates the research done
Scientific abstract (pdf 1K)   Full text (pdf 11240K)

M.B. Blom
Bachelor programme: Informatica July 13th, 2018
Institute: ILLC Research group: Logic & Computation Graduation thesis Supervisor: Christian Schaffner
photo of the author
Dirichlet L-series and transforming generators of principal ideals in lattice-based cryptography
We will discuss the principle of public-key cryptography, which is used when surfing the internet. In this case we have a person A trying to send a message to a person B. There is a third person E, who is trying to eavesdrop on the conversation. Person A encrypts a message using the public key, and sends the encrypted message to B. This encrypted message can only be decrypted using the secret key, so person E cannot see the contents of the message. When B receives the message, they can receive it using the secret key. Quantum computers can easily break encryption such as RSA. Even though current quantum computers are not powerful enough to actually break encryption, it is important to develop new future-proof cryptography. On of the possibilities is cryptography based on lattices. In this thesis we show an algorithm that breaks certain lattice-based cryptography by computing the secret key. This allows anyone to decrypt encrypted message, showing that the encryption scheme is not secure. Furthermore, the mathematical background of cryptography is discussed, including algebraic number theory. Some more results from algebraic number theory are also discussed.
picture that illustrates the research done
Scientific abstract (pdf 1K)   Full text (pdf 586K)

S. Molenaar
Bachelor programme: Informatica July 6th, 2018
Institute: UvA / Other Research group: UvA / Other Graduation thesis Supervisor: dr. G. Z├ívodszky
The Effect of a Non-Homogenous Erythrocytes Properties Distribution in In-Silico Blood Flows
Blood is a vital part of the human body that performs many important functions. The huge amount of tiny cells inside a blood suspension makes modelling blood a complex task. In this study a model that can simulate thousands of cells in human blood on a microscopic timescale is used to investigate what different distributions in properties such as cell volume can be implemented and the effect this has on the blood flow properties. Distribution in cell size opens up the ability to study the effects of conditions like iron deficiency and macrocytic anemia on both blood flow and transport properties.
picture that illustrates the research done
Scientific abstract (pdf 1K)   Full text (pdf 2026K)

E.M. Kooistra
Bachelor programme: Informatica June 29th, 2018
Institute: Informatics Institute Research group: System and Network Engineering Graduation thesis Supervisor: Ralph Koning
Hardening virtual environments against cache based side-channel attacks
Hosting applications in the cloud is cheaper because you only pay for the resources you use. However keeping all the customers sharing the resource isolated from each other is challenging. There are ways to break the isolation that hypervisors create, one method is using cache based side-channel attacks. We propose a method that makes it possible to detect cache based side-channel attacks on a Xen based system.
picture that illustrates the research done
Scientific abstract (pdf 1K)   For more info or full text, mail to: R.Koning@uva.nl

N.J.L. Kabel
Bachelor programme: Informatica June 29th, 2018
Institute: Informatics Institute Research group: Lecturer's Group Graduation thesis Supervisor: dr. R.G. Belleman
Persistent Tracking in Feature-Poor Environments
In many augmented reality solutions, visual markers are used to position virtual objects in the real world. A requirement for this solution is that the visual marker is always in view of the tracking camera. This poses a problem in situations where the virtual objects are far larger than the marker. This research proposes a solution for persistent tracking in feature-poor environments through a combination of multiple markers and the use of odometry in case no markers are visible.
picture that illustrates the research done
Scientific abstract (pdf 1K)   Full text (pdf 2327K)

R.J. Schlimbach
Bachelor programme: Informatica June 29th, 2018
Institute: Informatics Institute Research group: Intelligent Sensory Information Systems Graduation thesis Supervisor: Rein van den Boomgaard
photo of the author
Investigating scale in Receptive Fields Neural Networks
Jacobsen et al. proposed the Receptive Fields Neural Network in 2016, as a modification of the Convolution Neural Network design. This design replaces the convolution kernals of the CNN design with a weighted sum of convolutions with some fixed basis. Jacobsen et al. and Verkes showed the advantages of the RFNN design in their respective papers. Both Jacobsen et al. and Verkes have in their papers confirmed the similar performance of the RFNN network compared to a regular CNN. What is still remains uninvestigated, is the impact of the scale parameter of the Gaussian derivatives which fill the fixed kernels on the performance of the RFNN network design. Verkes simply chose a scale of 1.5 and 1 for the first and second layer of the RFNN in his experiments, but this choice remains unfounded. It is the ultimate hope that the scale parameter might be learnt by the network resulting in the network selecting the best 'scale' to examine an input image at. However, first a quantitative analysis should be performed on the general impact of the scale parameter on the performance of a simple RFNN, which is what this paper will try to do.
picture that illustrates the research done
Scientific abstract (pdf 2K)   Full text (pdf 723K)

D.B. de Haan
Bachelor programme: Informatica June 28th, 2018
Institute: Informatics Institute Research group: Institute for Informatics - Other Graduation thesis Supervisor: Taco Walstra
photo of the author
Energy Efficiency Analysis of the LEACH Protocol in Wireless Sensor Networks
Wireless sensor networks (WSN) are characterised by their energy constraints. The limited amount of available energy means energy efficiency is an important goal for every WSN since the energy consumption directly impacts the lifetime of the network. Choosing an energy efficient routing protocol is thus essential to minimise the energy consumption. One popular and important routing protocol for WSN is LEACH. In this thesis we analyse the energy efficiency of LEACH. More specifically, we analyse LEACH with different network sizes and different energy quantity. We will test different values for these test cases and observe how it impacts the lifetime of a WSN. The experiments are all simulated using the NS3 simulator. We have implemented the LEACH protocol in NS3 in order to analyse its energy efficiency.
picture that illustrates the research done
Scientific abstract (pdf 1K)   For more info or full text, mail to: T.R.Walstra@uva.nl

J.D. Moolhuizen
Bachelor programme: Informatica June 21st, 2018
Institute: Informatics Institute Research group: Institute for Informatics - Other Graduation thesis Supervisor: Anthony van Inge
photo of the author
Stochastic processing for computer vision applications
Modern processors face several design challenges. These challenges prevent processors from becoming exponentially faster despite the exponential decrease in size of processor components over the past few decades. In this paper we explore an old processing paradigm from the time before digital processing became the industry standaard to see how this stochastic manner of processing may help us in addressing the power wall, ILP wall and memory wall. This research proposes stochastic hardware for the Sobel operator, a stochastic comparator, and a stochastic median filter. In addition, we demonstrate the usage of stochastic bundle processing for image processing applications.
picture that illustrates the research done
Scientific abstract (pdf 1K)   Full text (pdf 3284K)

Previous  1  2  3  4  5  6  7  8  9  10  11  Next  

This page is maintained by thesis@science.uva.nl