BilVideo-7 : video parsing, indexing and retrieval

Ankara : The Department of Computer Engineering and the Institute of Engineering and Science of Bilkent University, 2010.Thesis (Ph. D.) -- Bilkent University, 2010.Includes bibliographical references leaves 91-103.Video indexing and retrieval aims to provide fast, natural and intuitive access to large video collections. This is getting more and more important as the amount of video data increases at a stunning rate. This thesis introduces the BilVideo-7 system to address the issues related to video parsing, indexing and retrieval. BilVideo-7 is a distributed and MPEG-7 compatible video indexing and retrieval system that supports complex multimodal queries in a unified framework. The video data model is based on an MPEG-7 profile which is designed to represent the videos by decomposing them into Shots, Keyframes, Still Regions and Moving Regions. The MPEG-7 compatible XML representations of videos according to this profile are obtained by the MPEG-7 compatible video feature extraction and annotation tool of BilVideo-7, and stored in a native XML database. Users can formulate text, color, texture, shape, location, motion and spatio-temporal queries on an intuitive, easy-touse visual query interface, whose composite query interface can be used to formulate very complex queries containing any type and number of video segments with their descriptors and specifying the spatio-temporal relations between them. The multithreaded query processing server parses incoming queries into subqueries and executes each subquery in a separate thread. Then, it fuses subquery results in a bottom-up manner to obtain the final query result and sends the result to the originating client. The whole system is unique in that it provides very powerful querying capabilities with a wide range of descriptors and multimodal query processing in an MPEG-7 compatible interoperable environment.Baştan, MuhammetPh.D

Visual servoing of mobile robots using potential fields /

The popularity of autonomous mobile robots have been rapidly increasing due to their new emerging application areas, from room cleaning, tourist guidance to space explorations. However, the development of a satisfactory control algorithm that will enable the autonomous mobile robots to navigate safely especially in dynamic environments is still an open research problem. In this work, a newly proposed potential field based control method is implemented, analyzed, and improvements are suggested based on experimental results obtained from a real robot. The experimental system, planned to be the groundwork for robot soccer team, consists of an overhead global vision camera, personal computer, wireless module, and a non-holonomic mobile robot, which is supposed to navigate safely among obstacles and reach its goal point. Images of the robots operating area are acquired by the camera, color processed by the PC in real-time to retrieve the required position and orientation information of the robot, goal, and obstacles. Then, the control algorithm is applied, and resulting reference wheel velocities are sent to the robot via wireless link. Finally, robot has to drive with these reference velocities for safe navigation and goal tracking. Experimental results in the form of motion history images, graphs and movies are presented to demonstrate the successful as well as problematic aspects of the implemented algorithm and the setup

Sliding mode based behavior control

In this work, we suggested a new approach for the control of a mobile robot capable of being a building block of an intelligent agent. This approach includes obstacle avoidance and goal tracking implemented as two different sliding mode controllers. A geometry based behavior arbitration is proposed for fusing the two outputs. Proposed structure is tested on simulations and real robot. Results have confirmed the high performance of the method

Sliding mode based obstacle avoidance and target tracking for mobile robots

In this work, we suggested a solution for the basic tasks of a mobile robot capable of being a building block of an intelligent agent in group. This solution includes obstacle avoidance and goal tracking implemented as two different controllers. A geometry based behavior arbitration is proposed for fusing the output of those two controllers. Proposed structure is tested both on simulations and on real robot with different scenarios. Results have confirmed the high performance of the method

Increased serum citrullinated histone H3 levels in COVID-19 patients with acute ischemic stroke = Akut ischaemiás stroke-ban szenvedő Covid-19-betegek körében megnő a szérum citrullinált hiszton H3-szintje

Prevalence of acute ische­mic stroke (AIS) is increased in patients with coronavirus disease 2019 (COVID-19). A proposed hypothesis is increased virus-induced propensity to hypercoagulation resulting in arterial thrombosis. Our aim was to provide evidence regarding the involvement of neutrophil extracellular trap (NET) formation (NETosis) in COVID-19 related AIS. Twenty-six consecutively enrolled COVID-19+ pneumonia patients with AIS, 32 COVID-19+ pneumonia patients without AIS and 24 AIS patients without COVID-19 infection were included to the study. Clinical characteristics of recruited patients were collected. Serum levels of citrullinated histone H3 (H3Cit; a factor of NETosis), IL-8 and C5a (mediators associated with NETosis) were measured by ELISA (enzyme-linked immunosorbent assay). H3Cit levels were significantly higher in COVID-19+ AIS patients, whereas all study groups showed comparable IL-8 and C5a levels. There were no significant differences among etiological subgroups of AIS patients with or without COVID-19. AIS patients with COVID-19 showed relatively increased white blood cell, lymphocyte, neutrophil, D-dimer, C-reactive protein and procalcitonin levels than control groups. H3Cit levels did not correlate with clinical/prognostic features and inflammation parameters. H3Cit and IL-8 levels were correlated in COVID-19 patients without stroke but not in COVID-19 positive or negative AIS patients. Increased levels of inflammation parameters and H3Cit in COVID-19 related AIS suggest that NETosis may cause susceptibility to arterial thrombosis. However, H3Cit levels do not correlate with clinical severity measures and inflammation parameters diminishing the prognostic biomarker value of NETosis factors. Moreover, the link between IL-8 and NETosis appears to be abolished in AIS