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Yayın Standing waves for a generalized Davey-Stewartson system(IOP Publishing, 2006-10-27) Eden, Osman Alp; Erbay, SaadetIn this paper, we establish the existence of non-trivial solutions for a semi-linear elliptic partial differential equation with a non-local term. This result allows us to prove the existence of standing wave ( ground state) solutions for a generalized Davey-Stewartson system. A sharp upper bound is also obtained on the size of the initial values for which solutions exist globally.Yayın Spectral renormalization group for the Gaussian model and 𝜓4 theory on nonspatial networks(American Physical Society, 2015-08-06) Tuncer, Aslı; Erzan, AyşeWe implement the spectral renormalization group on different deterministic nonspatial networks without translational invariance. We calculate the thermodynamic critical exponents for the Gaussian model on the Cayley tree and the diamond lattice and find that they are functions of the spectral dimension, (d) over tilde. The results are shown to be consistent with those from exact summation and finite-size scaling approaches. At (d) over tilde = 2, the lower critical dimension for the Ising universality class, the Gaussian fixed point is stable with respect to a psi(4) perturbation up to second order. However, on generalized diamond lattices, non-Gaussian fixed points arise for 2 < <(d)over tilde> < 4.Yayın Adaptation of professional skills in the unit operations laboratory(2012) Rende, Deniz; Rende, Sevinç; Baysal, NihatWe introduce the design of three consecutive unit operations laboratory (UOL) courses that retain the academic rigor of the course while incorporating skills essential for professional careers, such as ability to propose ideas, develop practical solutions, participate in teamwork, meet deadlines, establish communication between technical support and suppliers and oversee financial issues. We follow up the course outcomes with a survey targeting the graduates of the program. The results show that the implementation of these skills varies across post-graduate careers, highlighting the need for adaptive approaches for different graduate trajectories in designing the course.Yayın Neuropsychiatric outcomes and caregiver distress in primary progressive aphasia(Wiley, 2023-01) Seçkin, Mustafa; Yıldırım, Elif; Demir, İlayda; Orhun, Ömer; Bülbül, Ezgi; Velioğlu, H. Aziz; Öget, Öktem; Yeşilot, Nilüfer; Çoban, Oğuzhan; Gürvit, HakanBackground: In this study, we aimed to outline the neuropsychiatric consequences of primary progressive aphasia (PPA) and to understand how neuropsychiatric symptomatology affects distress in caregivers. Methods: The Neuropsychiatric Inventory (NPI) including the distress index (NPI-Distress) was used. Additional information about the caregiver burden was obtained using Zarit Burden Interview (ZBI). NPI, NPI-Distress, and ZBI data from 17 patients with a clinical diagnosis of PPA were compared with 10 stroke aphasia patients. Neuropsychiatric symptomatology was investigated based on three clusters; Mood, Frontal/Comportmental, and Psychotic/Disruptive. Additionally, the Activities of Daily Living Questionnaire (ADLQ) was used to outline the functional impairment. Twelve healthy controls were included to compare the neurocognitive test scores with PPA and stroke aphasia groups. Results: A greater number of neuropsychiatric symptoms were observed in the PPA group compared to the stroke aphasia group. The number of symptoms in Mood, and Frontal/Comportmental clusters were greater than the number of symptoms in Psychotic/Disruptive clusters in the PPA group, whereas no significant relationship between the number of symptoms and symptom clusters was found in the stroke aphasia group. In the PPA group, a strong correlation was found between the NPI-Frequency × Severity scores and the NPI-Distress scores. Moreover, the NPI-Distress scores in the PPA group strongly correlated with the ZBI scores. Scores for anxiety, irritability/lability, and apathy had a stronger correlation with the NPI-Distress scores compared to the other NPI symptoms. The Communication subscale was the most impaired domain in the PPA group. Travel, and Employment and Recreation subscales showed greater functional impairment in the stroke aphasia group compared to the PPA group. Conclusions: Neuropsychiatric symptoms in PPA in our study were more frequent than previously reported. Furthermore, the distress index of the NPI was not only correlated with the severity of the neuropsychiatric symptoms but also reflected the overall burden on the caregivers in the PPA group.Yayın Strategies for the evolution of sex(American Institute of Physics Inc., 2001-12) Tüzel, Erkan; Sevim, Volkan; Erzan, AyşeThe maintenance of a macroscopic sexual population is addressed. As a scenario, the mechanism of random conversion to sex, in the presence of a constant rate of mutation is examined. This scenario is very closely related to "coevolution of cell senescence and diploid sexual reproduction in unicellular organisms." In this work, a "senescence clock" ticks off a finite lifetime for each bit string. Sexual reproduction resets the senescence of clock; unless this happens after a number of generations of cloning, the offspring stop dividing and die.Yayın Maximum likelihood blind channel estimation for space-time coding systems(Hindawi Publishing Corporation, 2002-05) Çırpan, Hakan Ali; Panayırcı, Erdal; Çekli, ErdinçSophisticated signal processing techniques have to be developed for capacity enhancement of future wireless communication systems, In recent years, space-time coding is proposed to provide significant capacity gains over the traditional communication systems in fading wireless channels. Space-time codes are obtained by combining channel coding, modulation, transmit diversity, and optional receive diversity in order to provide diversity at the receiver and coding gain without sacrificing the bandwidth. In this paper, we consider the problem of blind estimation of space-time coded signals along with the channel parameters. Both conditional and unconditional maximum likelihood approaches are developed and iterative solutions are proposed. The conditional maximum likelihood algorithm is based on iterative least squares with projection whereas the unconditional maximum likelihood approach is developed by means of finite state Markov process modelling. The performance analysis issues of the proposed methods are studied. Finally, some simulation results are presented.Yayın From past to present: spam detection and identifying opinion leaders in social networks(Yildiz Teknik Univ., 2022-06-22) Altınel Girgin, Ayşe Berna; Gümüşçekiçci, GizemOn microblogging sites, which are gaining more and more users every day, a wide range of ideas are quickly emerging, spreading, and creating interactive environments. In some cases, in Turkey as well as in the rest of the world, it was noticed that events were published on microblogging sites before appearing in visual, audio and printed news sources. Thanks to the rapid flow of information in social networks, it can reach millions of people in seconds. In this context, social media can be seen as one of the most important sources of information affecting public opinion. Since the information in social networks became accessible, research started to be conducted using the information on the social networks. While the studies about spam detection and identification of opinion leaders gained popularity, surveys about these topics began to be published. This study also shows the importance of spam detection and identification of opinion leaders in social networks. It is seen that the data collected from social platforms, especially in recent years, has sourced many state-of-art applications. There are independent surveys that focus on filtering the spam content and detecting influencers on social networks. This survey analyzes both spam detection studies and opinion leader identification and categorizes these studies by their methodologies. As far as we know there is no survey that contains approaches for both spam detection and opinion leader identification in social networks. This survey contains an overview of the past and recent advances in both spam detection and opinion leader identification studies in social networks. Furthermore, readers of this survey have the opportunity of understanding general aspects of different studies about spam detection and opinion leader identification while observing key points and comparisons of these studies.Yayın On the equilibrium of a rigid body suspended by a set of linear springs(John Wiley & Sons, 2000-08) Tokad, YılmazIn this paper an approach is described for determining equilibrium states of a rigid body suspended elastically in space by a set of linear springs. This system is considered as a two-terminal generalized spring with terminal across (translational and rotational velocities, V-G, omega(G)) and terminal through (terminal force and moment, f(G), m(G)) variables. The algorithmic approach used for the solution of six nonlinear and coupled equilibrium equations consists of two major steps. The first step is to assign an initial orientation to the rigid body which is represented by the transformation (rotation) matrix T(theta,n) and reduce the problem to the solution of force equations only through a computer program. This yields the position vector xi of a preselected point G on the rigid body. Although the terminal force f(G) becomes zero at this position, the calculated terminal moment m(G), in general, is not equal to zero. The second step is to try to determine the correct orientation of the rigid body based on an argument that the terminal moment should vanish. The same argument is also used for the solution of force equilibrium equations. These two steps are repeated several times until both f(G) and m(G) vanish simultaneously yielding an equilibrium state (xi,T(theta, n)). Application of the approach is illustrated through various examples. It is observed that, if there are nonstable equilibrium states of the system, then sometimes all possible physical equilibrium states may not be obtained with this approach.Yayın Polish-Russian relations: history, geography and geopolitics(East European Quarterly, 2008-03) Özbay, Fatih; Aras, Bülent[No abstract available]Yayın An approximate wave solution for perturbed KDV and dissipative NLS equations: weighted residual method(Işık University Press, 2019-06-21) Demiray, HilmiIn the present work, we modified the conventional "weighted residual method" to some nonlinear evolution equations and tried to obtain the approximate progressive wave solutions for these evolution equations. For the illustration of the method we studied the approximate progressive wave solutions for the perturbed KdV and the dissipative NLS equations. The results obtained here are in complete agreement with the solutions of inverse scattering method. The present solutions are even valid when the dissipative effects are considerably large. The results obtained are encouraging and the method can be used to study the cylindrical and spherical evolution equations.
