WoS İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://gcris.khas.edu.tr/handle/20.500.12469/4465

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Citation - WoS: 2
Citation - Scopus: 1
3D self-assemble formation of molybdenum disulfide (MoS2)-doped polyacrylamide (PAAm) composite hydrogels
(Tubitak Scientific & Technological Research Council Turkey, 2022) Özuğur Uysal, Bengü; Pekcan, Mehmet Önder; Uysal, Bengu Ozugur; Pekcan, Onder
Polyacrylamide (PAAm), a renowned member of the hydrogel class, has many uses throughout a wide range of industrial processes, including water absorbed diapers, contact lenses, wastewater treatment, biomedical applications such as drug delivery vehicles and tissue engineering because of its physical stability, durability, flexibility easier shaping, and so on. PAAm also provides new functionalities after the incorporation of inorganic structures such as molybdenum disulfide (MoS2). During the copolymerization process, the transmittance of all samples reduced significantly after a particular time, referred to as the gel point. Microgels form a tree above the gel point as projected by Flory-Stockmayer classical theory. Because of microgels positioned at the junction points of the Cayley tree, the addition of MoS2 results in strong intramolecular crosslinking and looser composites. Moreover, fractal geometry provides a quantitative measure of randomness and thus permits characterization of random systems such as polymers. Fractal dimension of these polymer composites is calculated from power-law-dependent scattered intensity. It was also confirmed that a hydrogel rapidly formed within a few seconds, indicating a 3D network formation inside the gel. These materials may have a great potential for application in wearable and implantable electronics due to this highly desired 3D self-assemble feature.
Citation - WoS: 1
Citation - Scopus: 1
Accelerated Trends in Tourism Marketing and Tourist Behaviour
(Routledge, 2023) Kozak, Metin; Kozak, Metin; Kozak, Metin
[No Abstract Available]
Citation - WoS: 6
Citation - Scopus: 5
The acquisition and use of relative clauses in Turkish-learning children's conversational interactions: a cross-linguistic approach
(Cambridge University Press, 2019) Arslan Uzundağ, Berna; Küntay, Aylin C.
Using a cross-linguistic approach, we investigated Turkish-speaking children's acquisition and use of relative clauses (RCs) by examining longitudinal child-caregiver interactions and cross-sectional peer conversations. Longitudinal data were collected from 8 children between the ages of 8 and 36 months. Peer conversational corpus came from 78 children aged between 43 and 64 months. Children produced RCs later than in English (Diessel, 2004) and Mandarin (Chen & Shirai, 2015), and demonstrated increasing semantic and structural complexity with age. Despite the morphosyntactic difficulty of object RCs, and prior experimental findings showing a subject RC advantage, preschool-aged children produced object RCs, which were highly frequent in child-directed speech, as frequently as subject RCs. Object RCs in spontaneous speech were semantically less demanding (with pronominal subjects and inanimate head nouns) than the stimuli used in prior experiments. Results suggest that multiple factors such as input frequency and morphosyntactic and semantic difficulty affect the acquisition patterns.
Citation - WoS: 0
Citation - Scopus: 0
Adaptive Sampling Noise Mitigation Technique for Feedback-Based Quantum Algorithms
(Springer international Publishing Ag, 2024) Karabacak, Özkan; Clausen, Henrik Glavind; Karabacak, Ozkan; Wisniewski, Rafal
Inspired by Lyapunov control techniques for quantum systems, feedback-based quantum algorithms have recently been proposed as alternatives to variational quantum algorithms for solving quadratic unconstrained binary optimization problems. These algorithms update the circuit parameters layer-wise through feedback from measuring the qubits in the previous layer to estimate expectations of certain observables. Therefore, the number of samples directly affects the algorithm's performance and may even cause divergence. In this work, we propose an adaptive technique to mitigate the sampling noise by adopting a switching control law in the design of the feedback-based algorithm. The proposed technique can lead to better performance and convergence properties. We show the robustness of our technique against sampling noise through an application for the maximum clique problem.
Citation - WoS: 4
Citation - Scopus: 4
Alternative Credit Scoring and Classification Employing Machine Learning Techniques on a Big Data Platform
(Institute of Electrical and Electronics Engineers Inc., 2019) Dağ, Hasan; Kiyakoğlu, Burhan Yasin; Rezaeinazhad, Arash Mohammadian; Korkmaz, Halil Ergun; Dağ, Hasan
With the bloom of financial technology and innovations aiming to deliver a high standard of financial services, banks and credit service companies, along with other financial institutions, use the most recent technologies available in a variety of ways from addressing the information asymmetry, matching the needs of borrowers and lenders, to facilitating transactions using payment services. In the long list of FinTechs, one of the most attractive platforms is the Peer-to-Peer (P2P) lending which aims to bring the investors and borrowers hand in hand, leaving out the traditional intermediaries like banks. The main purpose of a financial institution as an intermediary is of controlling risk and P2P lending platforms innovate and use new ways of risk assessment. In the era of Big Data, using a diverse source of information from spending behaviors of customers, social media behavior, and geographic information along with traditional methods for credit scoring prove to have new insights for the proper and more accurate credit scoring. In this study, we investigate the machine learning techniques on big data platforms, analyzing the credit scoring methods. It has been concluded that on a HDFS (Hadoop Distributed File System) environment, Logistic Regression performs better than Decision Tree and Random Forest for credit scoring and classification considering performance metrics such as accuracy, precision and recall, and the overall run time of algorithms. Logistic Regression also performs better in time in a single node HDFS configuration compared to a non-HDFS configuration.
Citation - WoS: 0
Citation - Scopus: 1
Analysis and Optimization of the Network Throughput in IEEE 802.15.13 based Visible Light Communication Networks
(IEEE, 2021) Baykaş, Tunçer; Elamassie, Mohammed; Baykas, Tuncer; Uysal, Murat
In line with the growing interest on visible light communication (VLC), IEEE has initiated standardization efforts on this emerging technology. In this work, we consider IEEE 802.15.13 Optical Wireless Personal Area Networks (OWPAN) standard draft. The underlying MAC protocol uses contention free and contention access periods. For a standard-compliant VLC network, we analyze the network load and propose an algorithm to improve the network throughput by proper selection of period lengths. Our suggested algorithm improves the network performance by at least 5% in the case of variable network traffic up to 15 active users.
Citation - WoS: 1
Citation - Scopus: 5
Analysis of deep learning based path loss prediction from satellite images
(IEEE, 2021) Baykaş, Tunçer; Ates, Hasan F.; Baykas, Tuncer; Gunturk, Bahadir K.
Determining the channel model parameters of a wireless communication system, either by measurements or by running electromagnetic propagation simulations, is a time-consuming process. Any rapid deployment of network demands faster determination of at least major channel parameters. In this paper, we investigate the idea of using deep convolutional neural networks and satellite images for channel parameters (i.e., path loss exponent n and shadowing factor sigma) prediction in a cellular network with aerial base stations. Specifically, we investigate the performance dependency of the method on three different factors: height of the transmitter antenna, quantization levels of the channel parameters and architectural design of CNN. The results presented in this paper show a high prediction accuracy of the channel parameters in real-time.
Citation - WoS: 1
An analysis of social media content shared by right-wing extremist groups in the United States, the Great Britain and Australia
(Istanbul Univ, Fac Communication, 2023) Baş, Özen; Bas, Ozen
The extreme right movements have increasingly appeared on social media, especially on Twitter and Facebook, coinciding with the 2019 New Zealand attack, the 2019 El Paso incident, and Britain's exit from the European Union in 2020. This study examines the content and the form of extreme right-wing activities on Facebook and Twitter to promote their ideologies. A qualitative content analysis was conducted on posts shared by extreme-right groups on public Facebook and Twitter accounts in Great Britain, the United States and Australia. The sample spans from March 15, 2019 to February 5, 2020. The posts were coded according to a coding instrument developed based on the existing literature spreading extremist ideologies on social media. The coding instrument consisted of categories and subcategories such as 'the protection of western values', 'anti-LGBT activism', 'anti-feminism', 'anti-Islam', 'anti-immigrant sentiments', 'fostering the white race', and 'anti-elitist populism'. Findings suggest that the most prevalent extremist ideologies on Facebook and Twitter posts were 'anti-elitist populism' and 'the protection of western values'. Also, extremist groups heavily shared posts that combined texts and images to spread their ideologies on social media.
Citation - WoS: 79
Citation - Scopus: 95
The association of the severity of obstructive sleep apnea with plasma leptin levels
(Amer Medical Assoc., 2003) Öztürk, Levent; Ünal, Murat; Tamer, Lülüfer; Çelikoğlu, Firuz
Objective: To examine whether circulating leptin levels correlate with the severity of disease in patients with obstructive sleep apnea. Design: Prospective nonrandomized study. Setting: Referral sleep laboratory for patients with sleep-disordered breathing and biochemistry laboratory. Patients: Thirty-two subjects (mean+/-SD age 47+/-12 years) who were referred for suspected sleep apnea underwent an overnight sleep study and fasting morning venous blood sampling. Patients were divided into 3 groups with respect to apnea-hypopnea index: (1) severe sleep apnea (n=8) apnea-hypopnea index greater than 20
Citation - WoS: 10
Citation - Scopus: 11
Automatic Adaptation of Hypermutation Rates for Multimodal Optimisation
(Assoc Computing Machinery, 2021) Çörüş, Doğan; Oliveto, Pietro S.; Yazdani, Donya
Previous work has shown that in Artificial Immune Systems (AIS) the best static mutation rates to escape local optima with the ageing operator are far from the optimal ones to do so via large hypermutations and vice-versa. In this paper we propose an AIS that automatically adapts the mutation rate during the run to make good use of both operators. We perform rigorous time complexity analyses for standard multimodal benchmark functions with significant characteristics and prove that our proposed algorithm can learn to adapt the mutation rate appropriately such that both ageing and hypermutation are effective when they are most useful for escaping local optima. In particular, the algorithm provably adapts the mutation rate such that it is efficient for the problems where either operator has been proven to be effective in the literature.
Citation - WoS: 5
Citation - Scopus: 5
Block Elimination Distance
(Springer Japan Kk, 2022) Yaşar Diner, Öznur; Giannopoulou, Archontia C.; Stamoulis, Giannos; Thilikos, Dimitrios M.
We introduce the parameter of block elimination distance as a measure of how close a graph is to some particular graph class. Formally, given a graph class g, the class B(G) contains all graphs whose blocks belong to G and the class A(G) contains all graphs where the removal of a vertex creates a graph in G. Given a hereditary graph class G, we recursively define G((k)) so that G((0)) = B(G) and, if k >= 1 G((k)) B(A(G((k-1))) ) N We show that, for every nontrivial hereditary class g, the problem of deciding whether G is an element of G((k)) is NP-complete. We focus on the case where G is minor-closed and we study the minor obstruction set of G((k)) i.e., the minor-minimal graphs not in G((k)). We prove that the size of the obstructions of G((k)) is upper bounded by some explicit function ofk and the maximum size of a minor obstruction of G. This implies that the problem of deciding whether G is an element of G((k)) is constructively fixed parameter tractable, when parameterized by k. Finally, we give two graph operations that generate members of G((k)) from members of G((k -1)) and we prove that this set of operations is complete for the class O of outerplanar graphs.Please check and confirm if the authors Given and Family names have been correctly identified for author znur YaYar Diner. All authors names have been identified conectly. Please confirm if the corresponding author is correctly identified. Amend if necessary.This is correct
Citation - WoS: 0
Block Elimination Distance
(Springer international Publishing Ag, 2021) Yaşar Diner, Öznur; Giannopoulou, Archontia C.; Stamoulis, Giannos; Thilikos, Dimitrios M.
We introduce the parameter of block elimination distance as a measure of how close a graph is to some particular graph class. Formally, given a graph class G, the class B(G) contains all graphs whose blocks belong to G and the class A(G) contains all graphs where the removal of a vertex creates a graph in G. Given a hereditary graph class G, we recursively define G((k)) so that G((0)) = B(G) and, if k >= 1, G((k)) = B(A(G((k-1)))). The block elimination distance of a graph G to a graph class G is the minimum k such that G is an element of G((k)) and can be seen as an analog of the elimination distance parameter, defined in [J. Bulian & A. Dawar. Algorithmica, 75(2):363-382, 2016], with the difference that connectivity is now replaced by biconnectivity. We show that, for every non-trivial hereditary class G, the problem of deciding whether G. G(k) is NPcomplete. We focus on the case where G is minor-closed and we study the minor obstruction set of G((k)) i.e., the minor-minimal graphs not in G((k)). We prove that the size of the obstructions of G((k)) is upper bounded by some explicit function of k and the maximum size of a minor obstruction of G. This implies that the problem of deciding whether G is an element of G((k)) is constructively fixed parameter tractable, when parameterized by k. Our results are based on a structural characterization of the obstructions of B(G), relatively to the obstructions of G. Finally, we give two graph operations that generate members of G((k)) from members of G((k-1)) and we prove that this set of operations is complete for the class O of outerplanar graphs. This yields the identification of all members O boolean AND G((k)), for every k is an element of N and every non-trivial minor-closed graph class G.
Citation - WoS: 3
Citation - Scopus: 3
Challenges of Teaching in a Different Culture: An Auto-Ethnographic Study
(Cognizant Communication Corp, 2021) Kozak, Metin
Teaching in a different culture and environment is always a challenging issue. This may last from a few months to a few years, depending on the consequences of personal characteristics and environmental situations. Based on a personal experience, this article investigates the possible cultural differences between the lecturer and students in a teaching environment and understanding how the student perceptions may gradually change and the student -lecturer interaction may evolve until the semester ends. In a methodological way, the conclusions were drawn out of a mixed-method approach that is composed of a personal observation of the lecturer (etic), and expressions, both verbal and written, and memories of other persons (students) within the same class (emit). In lights of Hofstede's cultural dimensions, the study addresses a list of practical implications as the lessons learned-presumably the best way to cope with the challenges of teaching in a different culture.
Citation - WoS: 0
Citation - Scopus: 0
Channel Estimation and Physical Layer Security in Optical MIMO-OFDM based LED Index Modulation
(IEEE, 2023) Panayırcı, Erdal; Panayırcı, Erdal; Khalighi, Mohammad Ali
In this paper, we propose a new and low-complexity channel estimation algorithm for the generalized LED index modulation (GLIM), recently proposed for visible-light communication systems based on multi-input multi-output (MIMO) and orthogonal frequency-division multiplexing (OFDM). For this scheme, denoted by GLIM-OFDM, we investigate the bit-error rate (BER), the mean-square error (MSE) of channel estimation, as well as the Cramer-Rao bound on the latter. Furthermore, we present a novel physical layer security (PLS) technique for the GLIM-OFDM scheme using precoding at the transmitter assuming it has the channel state information (CSI) between the LEDs and a legitimate user, but no knowledge of the CSI corresponding to eavesdroppers. The efficiency of the proposed PLS technique is demonstrated through numerical results.
Citation - WoS: 2
Citation - Scopus: 3
Channel Estimation Using Optical MIMO OFDM Based LED Index Modulation
(IEEE, 2021) Panayırcı, Erdal; Panayırcı, Erdal
In this paper, a new MIMO channel estimation technique is proposed for generalized LED index modulation (GLIM-OFDM) developed for multi-input multi-output (MIMO) orthogonal frequency division multiplexing (OFDM) based VLC systems. The mean square error (MSE) of the channel estimation algorithm, the bit error rate (BER) and the Cramer-Rao (CR) lower-bound of the system were obtained analytically and the performance of the algorithm according to the signal-to-noise ratio was investigated by computer simulations. From the obtained MSE, BER and CR curves it is concluded that the MSE performance of the proposed channel estimation algorithm is very high and the BER performance of the system obtained with the estimated channel information is very close to the BER performance in the case of perfect knowledge of the channel.
Citation - WoS: 2
Citation - Scopus: 2
Chemical profile, antiproliferative and antibacterial activities and docking studies of essential oil and hexane fraction of hydrosol from fresh leaf of Plectranthus amboinicus (Lour.) Spreng.
(Pergamon-Elsevier Science Ltd, 2023) Ibrahim, Enas I. E.; Yagi, Sakina; Tzanova, Tzvetomira; Schohn, Herve; Uba, Abdullahi Ibrahim; Zengin, Gokhan
Essential oils are commonly extracted from plants by hydrodistillation in which an aqueous phase called hydrosol is obtained. Like essential oil, this by-product of distillation can be a source of natural bioactive molecules with health benefits. This study aimed at the investigation of the chemical profile, antiproliferative and antibacterial activities of essential oil and hexane fraction of hydrosol from Plectrunthus amboinicus (family Lamiacease) fresh leaf cultivated in Sudan. Essential oil was obtained by hydrodistilation and hexane fraction (HF) was derived from hydrosol by liquid -liquid extraction. Results showed that the phenolic monoterpene thymol (72.9%) was the dominant component of the essential oil while the HF was characterized by the presence of long-chain (n-C29 to n-C68) alkanes (91.4%). The HF showed highest antiproliferative activity against the colon cancer HT29 (IC50 9.2 mu g/mL) and HCT116 (IC50 7.7 mu g/mL) cell lines. The essential oil exerted best antibacterial activity with highest inhibition (22.0-22.3 mm) and minimum inhibitory concentration (31 mu g/mL) against the Gram positive bacteria Bacillus subtilis and Staphylococcus aureus. In silico study showed that the major components of the oil displayed higher docking scores than those present in the HF suggesting an antagonistic effect by other molecules in the essential oil. In conclusion, beside the essential oil, the hydrosol possesses promising bioactive composition suggesting that it could be exploited for further therapeutic applications.
Citation - WoS: 0
The Choice of Law in the Infringement of Intellectual Property Rights by Soft Law Provisions
(Istanbul Univ, 2020) Ömeroğlu, Ekin
This study deals with the party autonomy principle as a connecting factor in the infringement of intellectual property rights in the light of soft law provisions. The territoriality principle and the lex loci protectionis rule govern as the main doctrines of law applicable to intellectual property infringement disputes. However, several academic projects from all over the world (the Principles by the American Law Institute, the Principles by the European Max Planck Group on Conflict of Laws in Intellectual Property, the Japanese Transparency Proposal, the Joint Principles drafted by members of the Private International Law Association of Korea, Japanese Waseda University Global COE Project and the Draft Guidelines on Intellectual Property in Private International Law of The International Law Association Intellectual Property and Private International Law Committee) suggested the party autonomy principle for the infringement of intellectual property rights in contrast to Article 8(3) of the Rome II Regulation. All these principles have no legally binding effect, but they are a set of principles that could be used both by international and national legislative bodies and courts. Moreover, the party autonomy principle in intellectual property infringement cases has been accepted by Turkish Private International Law Act (PILA), Swiss PILA and Chinese PILA. The purpose of this study is to analyse both soft law and national law provisions comparatively. Although the common aspect of the legal principles is to accept the will of the party, all of the provisions differ in several aspects. This study attempts to analyse and evaluate the suggested developments of the choice of law for intellectual property infringement cases.
Co-Insurance and Rights of Subrogation Post-gard Marine and Energy V China National Chartering Company Ltd
(Edward Elgar Publishing Ltd, 2024) Noussia, Kyriaki; Aslan, Yavuz Can
Citation - WoS: 106
Citation - Scopus: 126
Cognitive impairment in amyotrophic lateral sclerosis: evidence from neuropsychological investigation and event-related potentials
(Elsevier Science Bv, 2002) Hanagasi, Hasmet A.; Gurvit, I. Hakan; Ermutlu, Numan; Kaptanoğlu, Gulustu; Karamürsel, Sacit; Idrisoğlu, Halil A.; Emre, Murat; Demiralp, Tamer
The presence of subclinical cognitive impairment in patients with amyotrophic lateral sclerosis (ALS) is investigated using neuropsychological assessment and event-related potential recordings (ERP). An extensive battery of neuropsychological tests assessing the domains of attention memory language visuo-spatial and executive functions were administered to 20 non-demented patients with sporadic ALS and 13 age- and education-matched healthy control subjects. Mismatch negativity (MMN) P3b P3a (novelty P300) and contingent negative variation (CNV) were recorded. ALS patients were significantly impaired in tests of working memory sustained attention response inhibition naming verbal fluency and complex visuo-spatial processing. The memory impairment seemed to be secondary to deficits in forming learning strategies and retrieval. In ERP recordings P3a and P3b amplitudes of ALS patients were lower compared with the controls P3a latencies were significantly longer and mean CNV amplitudes were higher. These results indicate subclinical impairment of cognitive functions in patients with ALS. The pattern of cognitive impairment suggests the dysfunction of the frontal network. (C) 2002 Elsevier Science B.V. All rights reserved.
Citation - WoS: 4
Citation - Scopus: 7
Collective dynamics of random Janus oscillator networks
(AMER PHYSICAL SOC, 2020) Eroğlu, Deniz; Eroğlu, Deniz; Rodrigues, Francisco A.; Moreno, Yamir
Janus oscillators have been recently introduced as a remarkably simple phase oscillator model that exhibits nontrivial dynamical patterns-such as chimeras, explosive transitions, and asymmetry-induced synchronization-that were once observed only in specifically tailored models. Here we study ensembles of Janus oscillators coupled on large homogeneous and heterogeneous networks. By virtue of the Ott-Antonsen reduction scheme, we find that the rich dynamics of Janus oscillators persists in the thermodynamic limit of random regular, Erdos-Renyi, and scale-free random networks. We uncover for all these networks the coexistence between partially synchronized states and a multitude of solutions of a collective state we denominate as a breathing standing wave, which displays global oscillations. Furthermore, abrupt transitions of the global and local order parameters are observed for all topologies considered. Interestingly, only for scale-free networks, it is found that states displaying global oscillations vanish in the thermodynamic limit.

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