| 1. |
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| 2. |
- Aad, G., et al.
(author)
-
- 2014
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Journal article (peer-reviewed)
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| 3. |
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| 4. |
- Özdinc, Mesut, et al.
(author)
-
Predicting the progress of COVID-19 : the case for Turkey
- 2020
-
In: Turkiye Klinikleri Journal of Medical Sciences. - : Türkiye Klinikleri. - 1300-0292 .- 2146-9040. ; 40:2, s. 117-119
-
Journal article (peer-reviewed)abstract
- The SIR model is applied to a dataset of 43 days from the beginning of the COVID-19 pandemic in Turkey. Model outputs regarding the estimates of effective reproduction number and peak date of the maximum number of actively infected are presented. Favorable impact of social distancing measures are observed in comparing model outputs on progressive days. Findings are valuable for policy and decision makers in shedding light on the next phases of the pandemic.
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| 5. |
- Özgünoglu, Mehmet, 1989, et al.
(author)
-
Numerical Assessment of Cavitation Erosion for a Nozzle Flow Configuration
- 2021
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In: 11th International Symposium on Cavitation (CAV2021).
-
Conference paper (peer-reviewed)abstract
- The main purpose of this study is to numerically investigate and predict the cavitation erosion mechanisms in a nozzle flow configuration. To do this, an injector type geometry is numerically investigated with the open-source CFD package OpenFOAM. A compressible Euler approached is applied for two operating conditions, where results are compared with other studies from the literature. Spectral statistics and maximum surface pressure results are compared with experiments. Results show that the proposed modelling approach is capable to explain main cavitation structures that promotes erosion.
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| 6. |
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| 7. |
- Aad, G., et al.
(author)
-
- 2012
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Journal article (peer-reviewed)
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| 8. |
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| 9. |
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| 10. |
- Özdür, N.A., et al.
(author)
-
Residual Intensity as a Morphological Identifier of Twinning Fields in Microscopic Image Correlation
- 2021
-
In: Experimental mechanics. - : Springer Nature. - 0014-4851 .- 1741-2765. ; 61:3, s. 499-514
-
Journal article (peer-reviewed)abstract
- Background: In the microscopic observation of deforming metals, it is well known that crystallite defects that accommodate strain can occasionally become visible, namely, they introduce image contrast to their locality. For microscopic digital image correlation (DIC) applications, this is typically known as a disturbance. Objective: Here, we explore a potential upside of these image-intensity offsets, to present a new mode of differential imaging that exclusively displays the underlying plasticity agents. Methods: For this, the intensity-offset signal is isolated with residual intensity, essentially the differential between reference- and deformed-configuration intensity of each material point. The premise is showcased over an autocatalytic twin band in Magnesium AZ31, with an advanced DIC instrument that utilizes bright-field optical microscopy. With robust area-scanning that utilizes in-situ corrective measures, a material field of around 5000 grains (13 μm average size) is sampled with a maximal intragranular resolution (~250 data points per grain) for this technique. For added robustness against the intensity alterations, a DIC algorithm (Augmented Lagrangian DIC) that enforces global kinematic compatibility constraints is utilized. Results: The calculated residual intensity map yields a detailed image of the twin networks that show a strong positional alignment with the strain localizations. At the band boundary, the twins (and their accompanying strain localization) protrude into the dormant material in a comb-like pattern. Conclusions: With a combination of high-resolution optics and defects that alter the surface topography, residual intensity presents a new in-situ microscopy mode that is tied to the DIC analysis. This principle also offers potential micro-deformation imaging capabilities for various other material-microscopy combinations.
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| 11. |
- Özeren, Hüsamettin Deniz, et al.
(author)
-
Starch/Alkane Diol Materials: Unexpected Ultraporous Surfaces, Near-Isoporous Cores, and Films Moving on Water
- 2020
-
In: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 5:44, s. 28863-28869
-
Journal article (peer-reviewed)abstract
- The aim of this study was to find alternative starch plasticizers to glycerol that yielded a less tacky material in high-moisture conditions without leading to starch crystallization. A range of glycerol films containing different potential plasticizers (linear alkane diols) were therefore produced, and it was shown that 1,3-propanediol, in combination with glycerol, was a possible solution to the problem. Several additional interesting features of the starch films were however also revealed. The larger diols, instead of showing plasticizing features, yielded a variety of unexpected structures and film properties. Films with 1,6-hexanediol and 1,7-heptanediol showed an ultraporous film surface and near-isoporous core. The most striking feature was that starch films with these two diols moved/rotated over the surface when placed on water, with no other stimulus than the interaction with water. Films with 1,8-octanediol and 1,10-decanediol did not show these features, but there was clear evidence of a structure with phase-separated crystallized diol in a starch matrix, as observed in high-resolution scanning electron microscopy (SEM) images.
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| 12. |
- Özkahraman, Özer, 1992-, et al.
(author)
-
Efficient Navigation Aware Seabed Coverage using AUVs
- 2021
-
In: Proceedings of 2021 IEEE International Conference on Safety, Security, and Rescue Robotics (SSRR), October 25-27 2021, New York, USA..
-
Conference paper (peer-reviewed)abstract
- Area coverage and robot navigation are two important research fields within robotics. However, their intersection has received limited attention. In coverage problems, perfect navigation is often assumed, and in robot navigation, the focus is often to minimize the localization error while traveling a given trajectory.The need for integration of the two becomes clear in environments with very sparse features or landmarks, for example when an Autonomous Underwater Vehicle (AUV) is to search the seafloor for dangerous objects, such as mines.The potential consequences of missing a mine due to navigation errors can be catastrophic.If the localization error is large, a trajectory that was designed to guarantee complete coverage might have missed significant parts of the area. Thus, the coverage trajectory must be planned with the navigation performance in mind, applying a combination of using large enough planned overlaps of sensor footprints to account for the position uncertainty, and reducing this uncertainty by re-visiting the known sparse landmarks.In this paper we compute trajectories that guarantee coverage for a given area under assumptions on worst case localization error growth.We further more compute upper bounds for how large areas can be covered using common coverage patterns and a single landmark, which leads to bounds on how sparse the landmarks can be in the regions to be covered.
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| 13. |
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| 14. |
- Öztürk, Ahmet Erdi
(author)
-
An alternative reading of religion and authoritarianism : the new logic between religion and state in the AKPs New Turkey
- 2019
-
In: Journal of Southeast European and Black Sea Studies. - : Routledge. - 1468-3857 .- 1743-9639. ; 19:1, s. 79-98
-
Journal article (peer-reviewed)abstract
- Since roughly 2011, the Turkish state and the ruling Justice and Development Party (AKP) have been going through a process of mutual transformation. Some of the historical apprehensions, biases and frustrations exhibited by Turkey as a middle power have been absorbed by the relatively reformist AKP. Conversely, the AKP and its undisputed leader Erdogan have seen their socio-political fears, power based conflicts and ethno-religious desires become dominant in all areas, including religion. As a consequence of this bilateral transformation, Turkey has become both an inclusionary and a hegemonic-authoritarian state, and at the same time a weak one. Within this new identity and structure of the state, Sunni Islam has become one of the regimes key focal points, with a new logic. This article seeks to explain the transformation of the relations between the AKPs Turkish state, religion and religious groups, by scrutinising Karrie Koesels logic of state-religion interaction in authoritarian regimes.
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| 15. |
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| 16. |
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| 17. |
- Özkirimli, Umut, et al.
(author)
-
Cosmopolitanism
- 2016
-
In: The Wiley-Blackwell Encyclopaedia of Race, Ethnicity and Nationalism. - Oxford, UK : John Wiley & Sons, Ltd. - 9781405189781 - 9781118663202
-
Book chapter (peer-reviewed)
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| 18. |
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| 19. |
- Öztayşi, Başar, et al.
(author)
-
Fuzzy Analytic Hierarchy Process with Interval Type-2 Fuzzy Sets
- 2014
-
In: Knowledge-Based Systems. - : Elsevier BV. - 0950-7051. ; 59, s. 48-57
-
Journal article (peer-reviewed)abstract
- The membership functions of type-1 fuzzy sets have no uncertainty associated with it. While excessive arithmetic operations are needed with type-2 fuzzy sets with respect to type-1’s, type-2 fuzzy sets generalize type-1 fuzzy sets and systems so that more uncertainty for defining membership functions can be handled. A type-2 fuzzy set lets us incorporate the uncertainty of membership functions into the fuzzy set theory. Some fuzzy multicriteria methods have recently been extended by using type-2 fuzzy sets. Analytic Hierarchy Process (AHP) is a widely used multicriteria method that can take into account various and conflicting criteria at the same time. Our objective is to develop an interval type-2 fuzzy AHP method together with a new ranking method for type-2 fuzzy sets. We apply the proposed method to a supplier selection problem.
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| 20. |
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| 21. |
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| 22. |
- Özlü, Neslihan
(author)
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Point forecasts from experience: An empirical examination of judgmental forecasting
-
Other publication (other academic/artistic)abstract
- The recent surge in prices brings predictions of future inflation into focus for many businesses. It is striking, however, that the forecasts of professionals with similar background in higher education are inherently heterogeneous. This poses the question of what drives the differences in forecasts. In the literature, different lifetime experiences are cited as a source of diversity (heterogeneity) in forecasts by individuals. We analyze a data set containing the individual point forecasts of monthly inflation rates made by 26 professional forecasters, over a period of 13 years for three different categories of inflation basket items. We find that besides available information, lifetime experience of inflation is a factor affecting the estimates of inflation and explaining the heterogeneity of forecasts. In the apparel category where, relative to other categories, inflation is easier to predict, forecasters rely mainly on available information. Finally, we observe differences across cohorts of forecasters when they are clustered according to lifetime experiences based on demographic data. Our results contribute to the broader literature on experiential effects on the forecasting task. Our findings have practical implications underscoring the need for managers to familiarize themselves with the work history and lifetime experiences of their employees.
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| 23. |
- Aad, G., et al.
(author)
-
- 2011
-
swepub:Mat__t (peer-reviewed)
|
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| 24. |
- Aad, G., et al.
(author)
-
- 2012
-
swepub:Mat__t (peer-reviewed)
|
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| 25. |
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| 26. |
- Özdogan, Özgecan, 1992-, et al.
(author)
-
Using Intelligent Reflecting Surfaces for Rank Improvement in MIMO Communications
- 2020
-
In: ICASSP 2020 - 2020 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP). - : IEEE. - 9781509066315 - 9781509066322 ; , s. 9160-9164
-
Conference paper (peer-reviewed)abstract
- An intelligent reflecting surface (IRS), consisting of reconfigurable metamaterials, can be used to partially control the radio environment and thereby bring new features to wireless communications. Previous works on IRS have particularly studied the range extension use case and under what circumstances the new technology can beat relays. In this paper, we study another use case that might have a larger impact on the channel capacity: rank improvement. One of the classical bottlenecks of point-to-point MIMO communications is that the capacity gains provided by spatial multiplexing are only large at high SNR, and high SNR channels are mainly appearing in line-of-sight (LoS) scenarios where the channel matrix has low rank and therefore does not support spatial multiplexing. We demonstrate how an IRS can be used and optimized in such scenarios to increase the rank of the channel matrix, leading to substantial capacity gains.
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| 27. |
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| 28. |
- Aad, G., et al.
(author)
-
- 2012
-
Journal article (peer-reviewed)
|
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| 29. |
- Aad, G., et al.
(author)
-
- 2011
-
swepub:Mat__t (peer-reviewed)
|
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| 30. |
- Özgü, Alay, et al.
(author)
-
End to End 5G Measurements with MONROE: Challenges and Opportunities
- 2018
-
In: 4th International Forum on Research and Technologies for Society and Industry (IEEE RTSI 2018). - : IEEE. - 9781538662823
-
Conference paper (peer-reviewed)abstract
- To be able to support diverse requirements of massive number of connected devices while also ensuring good user experience, 5G networks will leverage multi-access technolo- gies, deploy supporting operational mechanisms such as SDN and NFV, and require enhanced protocols and algorithms. For 4G networks, MONROE has been key to provide a common measurement platform and a set of methodologies available to the wider community. Such common grounds will become even more important and more challenging with 5G. In this paper, we elaborate on some key requirements for the design and implementation of 5G technologies and highlight the key challenges and needs for new solutions as seen in the context of 5G end-to-end measurements. We then discuss the opportunities that MONROE provides and more specifically, how a 5G-capable MONROE platform could facilitate these efforts.
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| 31. |
- Özkahraman, Özer, 1992-
(author)
-
Multi-Agent Mission Planning and Execution for Small Autonomous Underwater Vehicles
- 2023
-
Doctoral thesis (other academic/artistic)abstract
- Our planet is mostly covered in water, most of it still unexplored.In order to understand our environment better, oceanographers have been mapping and monitoring these waters using ship-mounted sensors and wired vehicles with limited range compared to the vastness of the oceans.The limited range and dependence on manned support vehicles has kept missions expensive and infrequent.To solve this problem, the sensors need to become independent of support vehicles, they need to venture into completely unexplored, unmapped regions of the seas by themselves and safely return with the data.This is where autonomous underwater vehicles (AUVs) have started to make a difference.In this thesis we investigate how multiple small AUVs can be utilized to efficiently and accurately sense very large volumes of water.Water absorbs electromagnetic radiation, meaning satellite-based global positioning systems (we will use GPS to refer to any such system), wide-angle cameras and radio communications are infeasible.These constraints ultimately result in uncertain localization of the vehicles.Furthermore, the vehicles are under constant disturbances from the water currents, fish and bio-fouling, which result in the dynamics of the vehicles being uncertain or even changing during the mission.In the first part of this thesis, we focus on the large-scale sensing problem under localization uncertainties by examining the caging and coverage problems.In the coverage problem, each AUV is uncertain about its exact position while tasked with sensing a stationary area.We show that we can still guarantee complete coverage and formulate the efficiency characteristics of different approaches.Furthermore, we show that when the vehicles are equipped with sensors and low-bandwidth communication methods, we can increase the effective range of a team of AUVs considerably by utilizing loop-closures over shared pose-graphs. In the caging problem, the localization uncertainty is focused on the entity that is being caged, its location is unknown but bounded.We show that through a combination of algorithms, the caging problem can be solved and a solution can be guaranteed, while simultaneously producing a list of specifications for the mission.In the second part, we focus on the individuals of the team and what they need to do in order for the team of AUVs to succeed.First, we identify that when there is a team of cooperative vehicles working together, conflicting goals rise.Each vehicle needs to pick between satisfying its own constraints and the constraints that come from being in a team. We propose a solution to this problem through a combination of Control Barrier Function (CBF) and Behavior Trees (BT).Secondly, we examine the possibility that a vehicle might undergo physical changes, like a broken thruster, that result in the vehicle being unable to complete the entire mission.Even in such a scenario, if the broken vehicle can still move to contact a normal one, the rest of the team can compensate through re-planning and the overall mission can still be completed.To do so, the broken vehicle must compensate for the change until a rendezvous.We propose a data-driven pipeline that can detect and plan around such a physical change within some bounds.
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| 32. |
- Karlsson, Magnus
(author)
-
- 2006
-
Reports (peer-reviewed)
|
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| 33. |
- Aad, G., et al.
(author)
-
- 2013
-
Journal article (peer-reviewed)
|
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| 34. |
|
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| 35. |
- Özdemir, O., et al.
(author)
-
Anticancer effects of novel NSAIDs derivatives on cultured human glioblastoma cells
- 2020
-
In: Zeitschrift für Naturforschung C - A Journal of Biosciences. - : Walter de Gruyter GmbH. - 0939-5075 .- 1865-7125.
-
Journal article (peer-reviewed)abstract
- Several epidemiologic, clinical and experimental reports indicate that nonsteroidal anti-inflammatory drugs (NSAIDs) could have a potential as anticancer agents. The aim of this study was the evaluation of cytotoxic potential in human glioblastoma cells of novel synthesized NSAID derivatives, obtained by linking, through a spacer, α-lipoic acid (ALA) to anti-inflammatory drugs, such as naproxen (AL-3, 11 and 17), flurbiprofen (AL-6, 13 and 19) and ibuprofen (AL-9, 15 and 21). The effects on the level of gene expression were also determined using quantitative real-time polymerase chain reaction (qRT-PCR) analysis. According to our results, NSAID derivatives exhibited concentration dependent cytotoxic effects on U87-MG cell line when compared with the control group. Moreover, treatment of the most active compounds (AL-3, AL-6 and AL-9) caused upregulation of tumor suppressor gene PTEN and downregulation of some oncogenes such as AKT1, RAF1 and EGFR. In conclusion, our results revealed that AL-3, AL-6 and AL-9 could be suitable candidates for further investigation to develop new pharmacological strategies for the prevention of cancer.
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| 36. |
- Özeren, Hüsamettin Deniz, et al.
(author)
-
Role of Hydrogen Bonding in Wheat Gluten Protein Systems Plasticized with Glycerol and Water
- 2021
-
In: Polymer. - : Elsevier BV. - 0032-3861 .- 1873-2291. ; 232, s. 124149-
-
Journal article (other academic/artistic)abstract
- Many biopolymers are stiff and brittle and require plasticizers. To optimize the choice and amount of plasticizer, the mechanisms behind plasticization need to be understood. For polar biopolymers, such as polysaccharides and proteins, plasticization depends to a large extent on the hydrogen bond network. In this study, glycerol-plasticized protein systems based on wheat gluten were investigated, in combination with the effects of water. The methodology was based on a combination of mechanical tests and molecular dynamics simulations (MD). The simulations accurately predicted the glycerol content where the experimental depression in glass transition temperature (Tg) occurred (between 20 and 30 wt.% plasticizer). They also predicted the strong water-induced depression in Tg. Detailed analysis revealed that in the dry system, the main effect of glycerol was to break protein-protein hydrogen bonds. In the moist system, glycerol was partly outcompeted by water in forming hydrogen bonds with the protein, making the glycerol plasticizer less effective than in dry conditions. These results show that MD can successfully predict the plasticizer concentration at which the onset of efficient plasticization occurs. MD can therefore be an important tool for understanding plasticizer mechanisms, even in a complex system, on a level of detail that is impossible with experiments.
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| 37. |
- Özkahraman, Özer, 1992-, et al.
(author)
-
Data-Driven Damage Detection and Control Adaptation for an Autonomous Underwater Vehicle
- 2022
-
In: 61st IEEE Conference on Decision and Control (CDC), 2022.
-
Conference paper (peer-reviewed)abstract
- Underwater robotic exploration missions typically involve traveling long distances without any human contact.The robots that go on such missions risk getting damaged by the unknown environment, accruing great costs and missed opportunities.Thus it is important for the robot to be able to accommodate unknown changes to its dynamics as much as possible and attempt to finish the given mission, or at the very least move itself to a retrievable position.In this paper, we show how we can detect physical changes to the robot reliably (79\% on real robot data) and then incorporate these changes through adapting the model to the data followed by automated control redesign. We adopt a piecewise-affine (PWA) modelling of the dynamics that is well suited for low data regime learning of the dynamics and provides a structure for computationally efficient control synthesis.We demonstrate the effectiveness of the proposed method on a combination of real robot data and simulated scenarios.
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| 38. |
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| 39. |
- Miranda Carranza, Pablo, 1972-, et al.
(author)
-
- 2009
-
Conference paper (other academic/artistic)abstract
- This paper gives an overview of the approach of working methods at the Aedas R&DComputational Design and Research [CDR] Group. It first contextualizes research inarchitectural practice and tries to propose an explanation for the difficulties inimplementing it; then explains the evolution of the groups’ computing approach frombespoke to heuristic sets of lightweight applications. It concludes with examples of thedeveloped computational design approach.
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| 40. |
- Ryberg, Ingrid, 1976
(author)
-
- 2019
-
In: Which Human Rights? Film Festival Istanbul.
-
Other publication (other academic/artistic)
|
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| 41. |
- Aad, G., et al.
(author)
-
- 2014
-
In: Physical Review C (Nuclear Physics). - 0556-2813 .- 1089-490X. ; 90:4
-
Journal article (peer-reviewed)
|
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| 42. |
- Aad, G., et al.
(author)
-
- 2013
-
Journal article (peer-reviewed)
|
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| 43. |
- Aad, G., et al.
(author)
-
- 2012
-
swepub:Mat__t (peer-reviewed)
|
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| 44. |
- Aad, G., et al.
(author)
-
- 2012
-
Journal article (peer-reviewed)
|
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| 45. |
- Aad, G., et al.
(author)
-
- 2014
-
In: Physical Review C (Nuclear Physics). - 0556-2813 .- 1089-490X. ; 90:2
-
Journal article (peer-reviewed)
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| 46. |
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| 47. |
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| 48. |
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| 49. |
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| 50. |
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