Browsing by Author "Eren, Saban"

Now showing 1 - 6 of 6

A general characterization of the stochastic optimal combined control of mean field stochastic systems with application
(Springer Berlin Heidelberg, 2018) Shahlar Meherrem; Mokhtar Hafayed; Deniz Hasan Guçoglu; Şaban Eren; Hafayed, Mokhtar; Meherrem, Shahlar; Gucoglu, Deniz H.; Eren, Saban
In this paper a general characterization of the optimal stochastic combined control for mean-field jump-systems is derived by applying mixed convex-spike perturbation method. The diffusion coefficient depends on the continuous control variable and the control domain is not necessary convex. In our combined mean-field control problem we discuss two classes of jumps for the state processes the inaccessible jumps which caused by Poisson martingale measure and the predictable ones which caused by the singularity of the control variable. Markowitz’s mean–variance portfolio selection problem with intervention control is discussed. © 2020 Elsevier B.V. All rights reserved.
Citation - Scopus: 14
Implementation and comparison of machine learning classifiers for information security risk analysis of a human resources department
(2010) Mete Eminaǧaoǧlu; Şaban Eren; Eminagaoglu, Mete; Eren, Saban
The aim of this study is threefold. First a qualitative information security risk survey is implemented in human resources department of a logistics company. Second a machine learning risk classification and prediction model with proper data set is established from the results obtained in this survey. Third several classifier algorithms are tested where their training and test performances are compared using error rates ROC curves Kappa statistics and F-measures. The results show that some classifier algorithms can be used to estimate specific human based information security risks within acceptable error rates. ©2010 IEEE. © 2011 Elsevier B.V. All rights reserved.
Citation - WoS: 19
Citation - Scopus: 19
On optimal singular control problem for general Mckean-Vlasov differential equations: Necessary and sufficient optimality conditions
(John Wiley and Sons Ltd vgorayska@wiley.com Southern Gate Chichester West Sussex PO19 8SQ, 2018) Mokhtar Hafayed; Shahlar Meherrem; Şaban Eren; Deniz Hasan Guçoglu; Hafayed, Mokhtar; Meherrem, Shahlar; Eren, Saban; Gucoglu, Deniz Hasan
In this paper we derive the necessary and sufficient conditions for optimal singular control for systems governed by general controlled McKean-Vlasov differential equations in which the coefficients depend on the state of the solution process as well as of its law and control. The control domain is assumed to be convex. The control variable has 2 components ie the first being absolutely continuous and the second being singular. The proof of our result is based on the derivative of the solution process with respect to the probability law and a corresponding Itô formula. Finally an example is given to illustrate the theoretical results. © 2018 Elsevier B.V. All rights reserved.
Citation - WoS: 31
Citation - Scopus: 41
Prospective Comparison of 3 Dacryocystorhinostomy Surgeries: External Versus Endoscopic Versus Transcanalicular Multidiode Laser
(LIPPINCOTT WILLIAMS & WILKINS, 2015) Melike Balikoglu-Yilmaz; Tolga Yilmaz; Umit Taskin; Muhittin Taskapili; Mehmet Akcay; M. Faruk Oktay; Saban Eren; Taskapili, Muhittin; Eren, Saban; Oktay, M. Faruk; Yilmaz, Tolga; Akcay, Mehmet; Balikoglu-Yilmaz, Melike; Taskin, Umit
Purpose: To analyze the clinical outcomes of external (EX-) endoscopic (EN-) and transcanalicular multidiode laser (TC-) with dacryocystorhinostomy (DCR). Methods: Ninety-two patients with primary acquired nasolacrimal duct obstruction were enrolled (divided into EX-DCR [n = 33] EN-DCR [n = 30] and TC-DCR groups [n = 29]) in this prospective study. Primary outcome measures were the anatomical and functional success of operations at the last control examination. Secondary outcome measures were the ostium size surgical time and complications. Results: The difference in mean surgical time among the 3 groups was statistically significant (p < 0.0001). External DCR required the longest surgical time (46.6 +/- 15.3 minutes) while TC-DCR was the shortest (20.3 +/- 7.7 minutes). There were no significant differences between the groups regarding anatomical (81.8% 75.9% and 76.7% in EX- EN- and TC-DCR groups respectively, p = 0.824) and functional success rates (81.8% 72.4% and 73.3% in EX- EN- and TC-DCR groups respectively, p = 0.626). Final ostium size was the largest with EX-DCR (33.7 +/- 17.4 mm(2)) and smallest with EN-DCR (19.0 +/- 8.9 mm(2), p = 0.001). The complication rate was similar in all groups. The most common complications were the formation of granulation tissue (16.3%) and intranasal synechiae (9.8%) all of which led to surgical failure and were more frequent in the EN-and TC-DCR groups. Conclusions: External DCR EN-DCR and TC-DCR had similar success and complication rates in patients with primary acquired nasolacrimal duct obstruction. External DCR resulted in the largest ostium size. Transcanalicular DCR appeared to be effective with the shortest surgical time.
Software Evolution or Software Enhancement?
(IEEE, 2018) Kaan Kurtel; Saban Eren; Kurtel, Kaan; Eren, Saban
In the software engineering we use the words evolution improvement enhancement development change or maintenance to emphasize the activities after the delivery of a software product. These isomorphic words are a serious annoyance to people who care about the words they choose to use. The software evolution is the most common word we use for these actions. However the meaning of the word evolution there is a very strong influence of biology. This is even more noticeable when it comes to computer software. Many authors assess this ambiguity in the several works published in English. However the confusion between the words is even more prominent in Turkish. In this study to reduce the above concerns we proposed and advocated to use word software enhancement instead of software evolution.
Citation - WoS: 3
Citation - Scopus: 3
Variational principle for stochastic singular control of mean-field Levy-forward-backward system driven by orthogonal Teugels martingales with application
(INDERSCIENCE ENTERPRISES LTD, 2017) Mokhtar Hafayed; Shahlar Meherrem; Deniz H. Gucoglu; Saban Eren; Hafayed, Mokhtar; Meherrem, Shahlar; Gucoglu, Deniz H.; Eren, Saban
We consider stochastic singular control for mean-field forward-backward stochastic differential equations driven by orthogonal Teugels martingales associated with some Levy processes having moments of all orders and an independent Brownian motion. Under partial information necessary and sufficient conditions for optimality in the form of maximum principle for this mean-field system are established by means of convex variation methods and duality techniques. As an illustration this paper studies a partial information mean-variance portfolio selection problem driven by orthogonal Teugels martingales associated with gamma process as Levy process of bounded variation.