Ugur Ozdemir

Bio: Ugur Ozdemir is an academic researcher from Istanbul Technical University. The author has contributed to research in topics: Iterative design & Longitudinal static stability. The author has an hindex of 8, co-authored 14 publications receiving 309 citations.

Design of a pilot-centered visual decision-support system for airborne collision avoidance

Abstract: In this work we present a pilot-centered visual decision support system for flight critical collision avoidance using “dynamic 4D trajectory management”. The system utilizes an underlying automation support system, which is connected to the onboard avionics, and the NextGen/SESAR enhanced flight deck technologies enabling new Communication, Navigation and Surveillance (CNS) and System Wide Information Management (SWIM) services. The overall automation support system which embeds “dynamic 4D trajectory management” is envisioned to a) provide the pilots with alternative trajectories as tunnels-in-the-sky through avionics displays on the console and head-up/augmented reality displays in real-time, b) provide the flight crew with quantified and visual understanding of collision risks in terms of time, directions, and countermeasures, and c) provide autonomous conflict resolution as an autopilot mode. Thus, ensuring highly responsive and adaptive airborne collision avoidance in face of ever challenging scenarios that involve blunders, weather/ terrain/ obstacle/ new conflict hazards. The designed visual decision support system does not increase workload of the pilot and dilutes “tunneling effect” in interaction while increasing situational awareness. These algorithms and tools developed are currently being integrated on an Automation Support System for implementation on a Boeing 737-NG FNPT II Flight Simulator with synthetic vision and augmented reality.

Kinesiophobia Following Anterior Cruciate Ligament Reconstruction.

Abstract: Amac : Kinezyofobi’nin gundelik ve sportif aktivitelerin uzerindeki rolunu, Tempa Kinezyofobi skorunu (TSK) Tagner aktivite skoru (TAS) uzerindeki etkilerini arastirmaya ama c ladik. Hipotez: Yuksek Tempa Kinezyofobi skoru Tagner aktivite skorunu dusurur. Materyal Metod: Ocak 2010-Aralik 2016 yillari arasinda o n c apraz bag rekonstruksiyonu yapi lan 50 hasta c alismaya alindi. Tum hastalara Lysholm diz skorlamasi, Tagner aktivite skorlamasi ve Tempa Kinezyofobi skorlamasi yapildi. Hastalarin her iki dizine 30 derecede KT-1000 artrometre uygulandi. Tempa Kinezyofobi skoru, Tagner aktivite skoru ve Lysholm knee skoru ile karsilastirildi . Sonuclar: Hastalarin ortalama yasi 29.6 (18-50) ve minimum takip sureleri 12 ay idi. Hastalarin 20’sinde (%40) ayni zamanda meniskus yirtigi mevcuttu. Tagner aktivite skoru, Tempa Kinezyofobi skoru ile anlamli olarak negatif bir korelasyon oldugu goruldu. Yuksek Tempa kinezyofobi skoru olan hastalarda Tegner aktivite skoru dusuk, dusuk Tempa kinezyofobi skoru olan hastalarda Tegner aktivite skoru anlamli olarak yukek oldugu goruldu. Istatistiksel olarak TKS ve TAS Lysholm skorlari arasinda, meniskus yirtigi olan ve olmayan hastalar arasinda anlamli bir fark bulunmadi. Cikarim: Calismamiz diz fonksiyonlarinin, istenilen duzeyde olmasi, yaralanma oncesi gundelik aktivite ve sportif aktiviteye geri donus icin yeterli olmadigini gosterdi. Lysholm skoru yuksek olsa bile Kinezyofobini sportif aktiviteye geri donuste onemli rol oynamaktadir. Calismamiz sonuclarina gore, tum on capraz bag yirtigi icin opere edilecek hastalarin kinezyofobi hakkinda bilgilendirilmesini ve testin yapilmasini, ayrica, yuksek kinezyofobi skoru olan hastalara fizik tedavinin yaninda psikolojik terapi almalari oneririz.

Simulation and Control of Fixed Wing Aircraft after a Major Component Loss

Abstract: The objective of this paper is to find means to control and stabilize a fixed wing aircraft after loss of a major stabilization and/or control component or a failure during the flight. The method seeks a possible trim condition for the aircraft after the loss or failure. A smooth transition from the initial trim condition to the post failure trim condition is aimed. After the incident, it is desired that the aircraft follows a defined trajectory. One way to achieve this goal is to obtain trim conditions along this trajectory and apply control inputs accordingly. Various tools are developed to reach this goal such as aircraft models and the algorithms for three and six degree of freedom trim analyses, and nonlinear flight simulation.

Longitudinal Stability Analysis of a UAV under the Uncertainty of Two Stability Derivatives

Abstract: The longitudinal stability analysis of an aircraft is performed by the investigation of root locations of its transfer function’s denominator (the characteristic equation). However, this transfer function is obtained by linearizing aircraft dynamic model at a certain operation point (altitude and speed). However, aircraft have varying stability derivatives, therefore dynamic behavior, for different flight phases such as take-off, cruise, and landing. Thus, the stability investigation of the characteristic equation can be said to be valid only for a certain flight condition. In reality, stability derivatives have varying values depending on flight conditions. Therefore, an analysis including all possible values of stability derivatives in the flight envelope is required to guarantee stability. In this study, two most varying stability derivatives in the transfer function were taken as uncertain parameters. Gridding these two parameters to check the stability of the UAV for all possible flight conditions can be thought as a method, but it is very time-consuming, and it cannot assure the stability theoretically. A new simple approach, guaranteeing stability under the uncertainty of two stability derivatives, is developed by using the Edge and Bialas theorems. Here, the problem of the investigation of the stability under the uncertainty of two stability derivatives is reduced to the analysis of four polynomials. Thus, the stability characteristics of an airplane for a given flight envelope can be easily determined by just looking at the eigenvalues of the matrices obtained from these four polynomials.

Advanced Calculus I

Abstract: WITH the ever-widening scope of modern mathematical analysis and its many ramifications, it is quite impossible to include, in a single volume of reasonable size, an adequate and exhaustive discussion of the calculus in its more advanced stages. It therefore becomes necessary, in planning a thoroughly sound course in the subject, to consider several important aspects of the vast field confronting a modern writer. The limitation of space renders the selection of subject-matter fundamentally dependent upon the aim of the course, which may or may not be related to the content of specific examination syllabuses. Logical development, too, may lead to the inclusion of many topics which, at present, may only be of academic interest, while others, of greater practical value, may have to be omitted. The experience and training of the writer may also have, more or less, a bearing on both these considerations.Advanced CalculusBy Dr. C. A. Stewart. Pp. xviii + 523. (London: Methuen and Co., Ltd., 1940.) 25s.

An Overview of Small Unmanned Aerial Vehicles for Air Quality Measurements: Present Applications and Future Prospectives

Abstract: Assessment of air quality has been traditionally conducted by ground based monitoring, and more recently by manned aircrafts and satellites. However, performing fast, comprehensive data collection near pollution sources is not always feasible due to the complexity of sites, moving sources or physical barriers. Small Unmanned Aerial Vehicles (UAVs) equipped with different sensors have been introduced for in-situ air quality monitoring, as they can offer new approaches and research opportunities in air pollution and emission monitoring, as well as for studying atmospheric trends, such as climate change, while ensuring urban and industrial air safety. The aims of this review were to: (1) compile information on the use of UAVs for air quality studies; and (2) assess their benefits and range of applications. An extensive literature review was conducted using three bibliographic databases (Scopus, Web of Knowledge, Google Scholar) and a total of 60 papers was found. This relatively small number of papers implies that the field is still in its early stages of development. We concluded that, while the potential of UAVs for air quality research has been established, several challenges still need to be addressed, including: the flight endurance, payload capacity, sensor dimensions/accuracy, and sensitivity. However, the challenges are not simply technological, in fact, policy and regulations, which differ between countries, represent the greatest challenge to facilitating the wider use of UAVs in atmospheric research.

A review on the platform design, dynamic modeling and control of hybrid UAVs

Abstract: This article presents a review on the platform design, dynamic modeling and control of hybrid Unmanned Aerial Vehicles (UAVs). For now, miniature UAVs which have experienced a tremendous development are dominated by two main types, i.e., fixed-wing UAV and Vertical Take-Off and Landing (VTOL) UAV, each of which, however, has its own inherent limitations on such as flexibility, payload, axnd endurance. Enhanced popularity and interest are recently gained by a newer type of UAVs, named hybrid UAV that integrates the beneficial features of both conventional ones. In this paper, a technical overview of the recent advances of the hybrid UAV is presented. More specifically, the hybrid UAV's platform design together with the associated technical details and features are introduced first. Next, the work on hybrid UAV's flight dynamics modeling is then categorized and explained. As for the flight control system design for the hybrid UAV, several flight control strategies implemented are discussed and compared in terms of theory, linearity and implementation.