Sistem ve Kontrol Mühendisliği
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Browsing Sistem ve Kontrol Mühendisliği by Author "Acar, Burak."
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Item 3D stylus: an intuitive 3D pointer for volumetric radiological data(Thesis (M.S.)-Bogazici University. Institute for Graduate Studies in Science and Engineering, 2007., 2007.) Yağcı, Enver.; Acar, Burak.This work introduces a new human-computer interface(HCI) device for three dimensional (3D) visualized data. Although there are different approaches developed in the literature, 3D interfaces have not finished their development. The HCI we designed basically aims at taking an arbitrary cross-section (oblique slicing) from volumetric data. Additionally, the interface we called "3D Stylus" has an extra option which enables the user to draw two dimensional curves. The 3D Stylus is a colorful, long and thin structure like a pen. The 3D Stylus is tracked by using image processing algorithms. 3D information about the interface is acquired with the help of stereo processing techniques applied to the images come from the stereo camera. The 3D Stylus is a flexible tool that can be used for different purposes in different applications. In the thesis, we firstly develop a oblique slicing application using 3D Stylus as normal vector of slicer held by the user. Then another application is developed for 2D drawing, and the 3D Stylus used as a chalk. At the end of the thesis, experiments are presented. Users are asked to use the 3D Stylus and mouse interfaces in our applications. Results about efficiency of the 3D Stylus are given, compared with mouse.Item Seed-based and data-driven analyses of default mode network connectivity measures in dementia(Thesis (M.S.) - Bogazici University. Institute for Graduate Studies in Science and Engineering, 2017., 2017.) Kılıç, Başak.; Acar, Burak.Functional neuroimaging and its applications to neurodegenerative diseases and mental illnesses have created an enlarging area of interest that varying lines of research ranging from molecular biology to engineering contribute to. Among them, Alzheimer's disease has a critical importance by causing the largest number of dementia cases. Recently, mild and subjective cognitive impairments have also been associated with Alzheimer's as possible indicators of cognitive decline. Using resting-state fMRI to investigate functional connectivity measures and detect any abnormality within and between networks have yielded promising results that disclose information about the nature of the diseases. The objective of this thesis is to use varying resting-state fMRI methods to di erentiate between SCI, MCI and AD patients by investigating the changes within Default Mode Network (DMN). The obtained results indicate that the changes within the functional connectivity measures among DMN components can be detected independent of the method of choice, and the measures of connectivity di er among groups. Subsequent research would aim for detection of possible bio-markers that are present through several stages and nding a common framework where metrics obtained from di erent methods can be compared.