Erke Aribas

3D blood flow simulations in human arterial tree bifurcations

This paper intends to simulate 3D blood flow of carotid artery bifurcations using a suitable geometrical model with the help of various processing tools and methods. To understand flow characteristics of human blood flow, it is essential to model 3D human arterial tree with as many branches as possible. Geometric modeling of the artery network is structured using a commercial program (Mimics). Conversion of the medical raw data to the geometrical model requires preprocessing tools and software in order to clean the distorted data or irregular data. This step is handled by using Mimics Medical Graphics Software. Next step is conversion of geometric model to a flow model including the crucial preprocessing operation using TGrid which is a commercial preprocessing program. Further, computational grid generation methods are applied to enhance the flow model. In addition to that, for future work it is made possible to add more bifurcations on the computational model. Exporting the geometrical data into a well-known fluid solver (Fluent) requires certain group of simulations and analysis. Therefore, a source mesh file is created for initial simulations that include 3D steady, unsteady (transient) flows with upstream velocities in constant and sinus wave form. All cases are compared according to pressure, shear stress and velocity values.

Effects of using depletion interaction theory in variable hematocrit levels of bio-flows

In our study, hematocrit levels and differences in rheological properties of blood, especially in red blood cell (RBC) using depletion interaction theory are investigated. In simulation, we apply depletion interaction theory which is a chemical concept at mesoscale level and unite with bio-fluid mechanics at a macro scale level. In order to differentiate the advantages of this theory, two-phase simulations are performed and RBC aggregation is studied. Wall shear stresses (WSS), phase distributions and volume fractions, with a range of hematocrit levels of RBC are calculated using depletion theory for multi-phase simulation and compared with numerical and experimental data in literature.In our study, hematocrit levels and differences in rheological properties of blood, especially in red blood cell (RBC) using depletion interaction theory are investigated. In simulation, we apply depletion interaction theory which is a chemical concept at mesoscale level and unite with bio-fluid mechanics at a macro scale level. In order to differentiate the advantages of this theory, two-phase simulations are performed and RBC aggregation is studied. Wall shear stresses (WSS), phase distributions and volume fractions, with a range of hematocrit levels of RBC are calculated using depletion theory for multi-phase simulation and compared with numerical and experimental data in literature.

Realtime object detection in IoT (Internet of Things) devices

IoT (Internet of Things) is acommunication network that connects physical or things to each other or with a group all together. The use is widely popular nowadays and its usage has expanded into interesting subjects. Especially, it is getting more popular to research in cross subjects such as mixing smart systems with computer sciences and engineering applications together. Object detection is one of these subjects. Realtime object detection is one of the foremost interesting subjects because of its compute costs. Gaps in methodology, unknown concepts and insufficiency in mathematical modeling makes it harder for designing these computing algorithms. Algortihms in these applications can be developed with in machine learning and/or numerical methods that are available in scientific literature. These operations are possible only if communication of objects within theirselves in physical space and awareness of the objects nearby. Artificial Neural Networks may help in these studies. In this study, yolo algorithm which is seen as a key element for real-time object detection in IoT is researched. It is realized and shown in results that optimization of computing and analyzation of system aside this research which takes Yolo algorithm as a foundation point [10]. As a result, it is seen that our model approach has an interesting potential and novelty.

Personality identification by deep learning

In recent years, that researchers in psycho-social fields classify the personalities according to different criterias, is one of the most interesting studies. In the viewpoint of the artificial intelligence researches, it is considered that analyzing the personalities will provide achieving realistic character modellings and realizing more intelligent systems via engineering disiplines in future. Beside of methodological gaps and conceptual uncertainities, insufficiencies in the mathematical modellings make developing computational algorithm difficult for this issue. These algorithms can be developed by present numerical or machine learning based methods in the literature. It can be realized by a hybrid method as composition of them. Numerical methods with linear or nonlinear system can also be suitable. From the standpoint of uncertainities, probabilistic (Bayesian, Monte Carlo, etc.) or fuzzy approaches can elaborate the modelling. Machine learning based methods (Markovian, support vector machines, Boltzman machines or artificial neural networks, etc.) can provide benefit to this kind of the study. In this study, we propose deep neural network based personality identification system with dataset which is composed from given responses to a questionaire prepared as suitable to the purpose. Our approach is verified with the classification results related to this.

High altitude smart monitoring system integration by using a helium powered mechanical balloon

Weather Balloons are used excessively in numerous areas and applications today. High altitude balloons are usually unmanned balloons that may climb up to 40km. We propose a high-altitude balloon system design that is capable of self-tuning itself in order to stay at a predefined height limit [1]. This type of a balloon system may be very useful from monitoring geophysical and atmospheric events but also for a vessel to use technological devices such as relay points. This altitude balancing design also allows to be manipulated using a controlled mechanism and may be easily applied for scientific, engineering and industrial purposes. They are much more economic and they almost use no power when they are compared with the alternative technologies.

Design of unmanned semi-autonomous smart probe for near earth space research operations

To conduct studies related to our planet and its atmosphere at high altitudes above 100 km from the ground requires to overcome great challenges. These studies can include meteorological, geographical and astrophysical missions. In this paper, we designed a high altitude unmanned semi-autonomous probe with helium gas balloon for general purpose near Earth space studies. Also hardware architecture of our proposed system includes high performance computing module, Low-level control systems, propulsion/steering mechanisms, radio telemetry system, real-time measurement and data acquisition system, fail-safe mechanisms and real-time vision system. 3D solid design of the system contains helium gas balloon, main flight capsule (craft), peripheral equipment (e.g. cameras, battery packs, radio antenna, etc.) to be connected to the craft and payload capsule. In the future, our probe can be customized according to the other specified missions.

Oscillating shear index, time averaged wall shear index, relative residence time analysis in 3D structured analytical artery

This study investigates the bio-mechanics of one main artery model in a three dimensional analytical cylindrical generated geometry based on a real human artery. Structured geometry is a medium large (celiac) artery. Constant and sinus velocity profile is applied as an interpolated input. Non-Newtonian Carreau viscosity model and fluid-structure interaction (FSI) is applied numerically. Oscillating Shear Index (OSI), Time Averaged Wall Shear Stress Index (TAWSSI) and Relative Residence Time (RRE) as well as velocity, pressure and pressure are studied. As an example, stenosed areas can be studied with the help of the model. Then these values are compared and presented for their importance.