Yönetim Bilişim Sistemleri Bölümü Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12469/68

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Now showing 1 - 17 of 17

Citation - WoS: 6
Citation - Scopus: 10
A Competitive Intelligence Practices Typology in an Airline Company in Turkey
(Springer, 2020) Şahin, Murat; Bisson, Christophe
Oil prices, political instabilities, travel legislations, and many other competitive factors make it essential for any international airline with the instinct to survive to be on constant watch in such a fiercely competitive environment. To meet this need, it is vital for international airline companies to integrate competitive intelligence (CI) into their strategy building process. In this study, we create for the first time a typology of competitive intelligence practices of an international airline company (in Turkey), based on the model developed by (Wright et al.Journal of Strategic Marketing, 20(1), 19-33,2012), and it is one of the very first to investigate Competitive intelligence in this sector. Furthermore, we made a two-step cluster analysis to uncover hidden clusters that change the way of thinking within the company. Our findings show where the company would need to make improvements on the 6 strands of the model which are attitude, gathering, use, location, technological support, and IT support. Yet, that could lead towards stronger business performance. It might also inspire other companies of the airline sector and beyond.
Citation - WoS: 1
Citation - Scopus: 2
Continuous Dependence on Data for a Solution of the Quasilinear Parabolic Equation With a Periodic Boundary Condition
(Springer International Publishing Ag, 2013) Kanca, Fatma; Baglan, Irem Sakinc; Kanca, Fatma
In this paper we consider a parabolic equation with a periodic boundary condition and we prove the stability of a solution on the data. We give a numerical example for the stability of the solution on the data.
Citation - WoS: 5
Citation - Scopus: 5
Designing of Multi-Targeted Molecules Using Combination of Molecular Screening and in Silico Drug Cardiotoxicity Prediction Approaches
(Elsevier Science Inc, 2014) Buturak, Birce; Durdagi, Serdar; Noskov, Sergei Y.; Ildeniz, A. Tugba Ozal
We have previously investigated and reported a set of phenol- and indole-based derivatives at the binding pockets of carbonic anhydrase isoenzymes using in silico and in vitro analyses. In this study we extended our analysis to explore multi-targeted molecules from this set of compounds. Thus 26 ligands are screened at the binding sites of 229 proteins from 5 main enzyme family classes using molecular docking algorithms. Derived docking scores are compared with reported results of ligands at carbonic anhydrase I and II isoenzymes. Results showed potency of multi-targeted drugs of a few compounds from investigated ligand set. These promising ligands are then tested in silico for their cardiotoxicity risks. Results of this work can be used to improve the desired effects of these compounds by molecular engineering studies. In addition these results may lead to further investigation of studied molecules by medicinal chemists to explore different therapeutic aims. (C) 2014 Elsevier Inc. All rights reserved.
Citation - WoS: 6
Citation - Scopus: 7
Determination of an Unknown Heat Source From Integral Overdetermination Condition
(Springer International Publishing, 2018) Baglan, İrem Sakınç; Kanca, Fatma; Mishra, Vishnu Narayan
In this research we consider a coefficient problem of an inverse problem of a quasilinear parabolic equation with periodic boundary and integral over determination conditions. We prove the existence uniqueness and continuously dependence upon the data of the solution by iteration method. Also we consider numerical solution for this inverse problem using linearization and finite difference method is proved.
Citation - WoS: 4
Citation - Scopus: 5
Development of a Supervised Classification Method To Construct 2d Mineral Maps on Backscattered Electron Images
(Tubitak, 2020) Camalan, Mahmut; Çavur, Mahmut
The Mineral Liberation Analyzer (MLA) can be used to obtain mineral maps from backscattered electron (BSE) images of particles. This paper proposes an alternative methodology that includes random forest classification, a prospective machine learning algorithm, to develop mineral maps from BSE images. The results show that the overall accuracy and kappa statistic of the proposed method are 97% and 0.94, respectively, proving that random forest classification is accurate. The accuracy indicators also suggest that the proposed method may be applied to classify minerals with similar appearances under BSE imaging. Meanwhile, random forest predicts fewer middling particles with binary and ternary composition, but the MLA predicts more middling particles only with ternary composition. These discrepancies may arise because the MLA, unlike random forest, may also measure the elemental compositions of mineral surfaces below the polished section.
Citation - WoS: 4
Citation - Scopus: 6
Harmony Search Algorithm Based Management of Distributed Energy Resources and Storage Systems in Microgrids
(MDPI, 2020) Ceylan, Oğuzhan; Sezgin, Mustafa Erdem; Goel, Murat; Verga, Maurizio; Lazzari, Riccardo; Kwaye, Marcel Pendieu; Sandroni, Carlo
Microgrids are composed of distributed energy resources (DERs), storage devices, electric vehicles, flexible loads and so on. They may either operate connected to the main electricity grid (on-grid operation) or separated from the grid (islanded operation). The outputs of the renewable energy sources may fluctuate and thus can cause deviations in the voltage magnitudes especially at islanded mode. This may affect the stability of the microgrids. This paper proposes an optimization model to efficiently manage controllable devices in microgrids aiming to minimize the voltage deviations both in on-grid and islanded operation modes. RSE Distributed Energy Resources Test Facility (DER-TF), which is a low voltage microgrid system in Italy, is used to verify the algorithm. The test system's data is taken through an online software system (REDIS) and a harmony search based optimization algorithm is applied to control the device parameters. The experimental results show that the harmony search based optimization approach successfully finds the control parameters, and can help the system to obtain a better voltage profile.
Citation - WoS: 5
Citation - Scopus: 5
Heuristic Methods for Postoutage Voltage Magnitude Calculations
(TUBITAK Scientific & Technical Research Council Turkey, 2016) Ceylan, Oğuzhan; Özdemir, Aydogan; Dağ, Hasan
Power systems play a significant role in every aspect of our daily lives. Hence their continuation without any interruption (or with the least duration of interruption due to faults or scheduled maintenances) is one of the key aims of electrical energy providers. As a result electrical energy providers need to check in great detail the integrity of their power systems by performing regular contingency studies of the equipment involved. Among others line and transformer outage simulations constitute an integral part of an electrical management system. Both accuracy and calculation speed depend on the branch outage model and/or the solution algorithms applied. In this paper the local constrained optimization problem of the single-branch outage problem is solved by intelligent methods: particle swarm optimization differential evolution and harmony search. Simulations of IEEE 14- 30- 118- and 300 -bus systems are computed both by intelligent methods and by AC load flow. The results of the intelligent method -based simulations and AC load flow -based simulations are compared in terms of accuracy and computation speed.
Citation - WoS: 16
Citation - Scopus: 34
The Impact of Text Preprocessing on the Prediction of Review Ratings
(Tubitak, 2020) Işık, Muhittin; Dağ, Hasan
With the increase of e-commerce platforms and online applications, businessmen are looking to have a rating and review system through which they can easily reveal the feelings of customers related to their products and services. It is undeniable from the statistics that online ratings and reviews attract new customers as well as increase sales by means of providing confidence, ratification, opinions, comparisons, merchant credibility, etc. Although considerable research has been devoted to the sentiment analysis for review classification, rather less attention has been paid to the text preprocessing which is a crucial step in opinion mining especially if convenient preprocessing strategies are found out to increase the classification accuracy. In this paper, we concentrate on the impact of simple text preprocessing decisions in order to predict fine-grained review rating stars whereas the majority of previous work focused on the binary distinction of positive vs. negative. Therefore, the aim of this research is to analyze preprocessing techniques and their influence, at the same time explain the interesting observations and results on the performance of a five-class-based review rating classifier.
Citation - WoS: 6
Citation - Scopus: 8
An Integrated Framework for Examining Innovation Alignment in Organizations
(World Scientific Publ Co Pte Ltd, 2018) Dilan, Ebru; Aydın, Mehmet Nafiz
Innovation has been promoted as a panacea to solve the long-standing problem of how organizations deal with complexities associated with uncertainty and instability in ever changing environments. information systems (IS) research focusing on innovation has adopted several perspectives to reveal a rich context in which the innovation surfaces as a phenomenon. Examination of a rich context may contribute to a better understanding of an extent to which uncertainty and instability can affect or be affected by innovation strategies that require various innovation efforts in an organization. In this regard one of the most critical issues is to ensure that these innovation efforts can achieve a successful outcome via their strategic and structural alignment. In this research we propose an integrated framework that addresses an innovation alignment issue by employing three high-level notions (strategic dimensions structural characteristics strategizing acts). The integrated framework has been used rigorously in two cases for an explorative purpose. Our interpretation of the evidence suggests that strategizing act as a high-level notion has an explanatory power to articulate the associations between strategic dimensions and structural characteristics. Among other findings we have observed that the closed incremental and process-oriented innovation strategy is particularly relevant to the corporate level whereas radical product-oriented and partially open innovation strategy is associated with a more exclusive innovation structure. © 2019 World Scientific Publishing Company.
Citation - WoS: 15
Citation - Scopus: 15
An Inverse Boundary Value Problem for a Second Order Elliptic Equation in a Rectangle
(Vilnius Gediminas Tech Univ, 2014) Mehraliyev, Yashar T.; Kanca, Fatma
In this paper the inverse problem of finding a coefficient in a second order elliptic equation is investigated. The conditions for the existence and uniqueness of the classical solution of the problem under consideration are established. Numerical tests using the finite-difference scheme combined with an iteration method is presented and the sensitivity of this scheme with respect to noisy overdetermination data is illustrated.
Citation - WoS: 8
Citation - Scopus: 7
An Inverse Coefficient Problem for a Quasilinear Parabolic Equation With Nonlocal Boundary Conditions
(Springer International Publishing Ag, 2013) Kanca, Fatma; Bağlan, İrem
In this paper the inverse problem of finding the time-dependent coefficient of heat capacity together with the nonlocal boundary conditions is considered. Under some natural regularity and consistency conditions on the input data, the existence, uniqueness and continuous dependence upon the data of the solution are shown. Some considerations on the numerical solution for this inverse problem are presented with an example.
Citation - WoS: 13
Citation - Scopus: 17
The Inverse Problem of the Heat Equation With Periodic Boundary and Integral Overdetermination Conditions
(Springer International Publishing Ag, 2013) Kanca, Fatma
In this paper the inverse problem of finding the time-dependent coefficient of heat capacity together with the solution of a heat equation with periodic boundary and integral overdetermination conditions is considered. The conditions for the existence and uniqueness of a classical solution of the problem under consideration are established. A numerical example using the Crank-Nicolson finite-difference scheme combined with the iteration method is presented.
Citation - WoS: 11
Citation - Scopus: 10
Numerical Solution and Distinguishability in Time Fractional Parabolic Equation
(Springer International Publishing Ag, 2015) Demir, Ali; Kanca, Fatma; Ozbilge, Ebru
This article deals with the mathematical analysis of the inverse problem of identifying the distinguishability of input-output mappings in the linear time fractional inhomogeneous parabolic equation D(t)(alpha)u(x t) = (k(x)u(x))(x) + r(t)F(x t) 0 < alpha = 1 with mixed boundary conditions u(0 t) = psi(0)(t) u(x)(1 t) = psi(1)(t). By defining the input-output mappings Phi[center dot] : kappa -> C-1[0 T] and psi[center dot] : kappa -> C[0 T] the inverse problem is reduced to the problem of their invertibility. Hence the main purpose of this study is to investigate the distinguishability of the input-output mappings Phi[center dot] and psi[center dot]. Moreover the measured output data f (t) and h(t) can be determined analytically by a series representation which implies that the input-output mappings Phi[center dot] : kappa -> C-1[0 T] and psi[center dot] : kappa -> C[0 T] can be described explicitly where Phi[r] = k(x)u(x)(x t
Citation - WoS: 33
Citation - Scopus: 44
Semantic and Syntactic Interoperability for Agricultural Open-Data Platforms in the Context of Iot Using Crop-Specific Trait Ontologies
(MDPI AG, 2020) Aydın, Şahin; Aydın, Mehmet Nafiz
In recent years, Internet-of-Things (IoT)-based applications have been used in various domains such as health, industry and agriculture. Considerable amounts of data in diverse formats are collected from wireless sensor networks (WSNs) integrated into IoT devices. Semantic interoperability of data gathered from IoT devices is generally being carried out using existing sensor ontologies. However, crop-specific trait ontologies-which include site-specific parameters concerning hazelnut as a particular agricultural product-can be used to make links between domain-specific variables and sensor measurement values as well. This research seeks to address how to use crop-specific trait ontologies for linking site-specific parameters to sensor measurement values. A data-integration approach for semantic and syntactic interoperability is proposed to achieve this objective. An open-data platform is developed and its usability is evaluated to justify the viability of the proposed approach. Furthermore, this research shows how to use web services and APIs to carry out the syntactic interoperability of sensor data in agriculture domain.
Citation - WoS: 12
Citation - Scopus: 15
Social Media Adoption: a Process-Based Approach
(Taylor & Francis Inc, 2016) Toker, Ayşegül; Seraj, Mina; Kuşçu, Asli; Yavuz, Ramazan; Koch, Stefan; Bisson, Christophe
This research conceptualizes and measures social media adoption (SMA) of companies with a process-based approach and explains its antecedents of micro- and macro-environment size and ownership as well as its consequence of intention to increase resources dedicated to social media. Based on data from 310 Turkish small and medium enterprises the study first develops a conceptual framework on the pillars of internal and external stakeholder focus as well as relationship and information oriented implementation. Based on these two dimensions it discusses the novel concepts of social customer relations social stakeholder communication social intelligence and social responsiveness related to SMA. The study further indicates that ownership type and micro environment play a role in SMA and that path dependence exists in the interplay of current adoption and future intentions.
A Sparsity-Preserving Spectral Preconditioner for Power Flow Analysis
(TUBITAK Scientific & Technical Research Council Turkey, 2016) Yetkin, Emrullah Fatih; Dağ, Hasan
Due to the ever-increasing demand for more detailed and accurate power system simulations the dimensions of mathematical models increase. Although the traditional direct linear equation solvers based on LU factorization are robust they have limited scalability on the parallel platforms. On the other hand simulations of the power system events need to be performed at a reasonable time to assess the results of the unwanted events and to take the necessary remedial actions. Hence to obtain faster solutions for more detailed models parallel platforms should be used. To this end direct solvers can be replaced by Krylov subspace methods (conjugate gradient generalized minimal residuals etc.). Krylov subspace methods need some accelerators to achieve competitive performance. In this article a new preconditioner is proposed for Krylov subspace-based iterative methods. The proposed preconditioner is based on the spectral projectors. It is known that the computational complexity of the spectral projectors is quite high. Therefore we also suggest a new approximate computation technique for spectral projectors as appropriate eigenvalue-based accelerators for efficient computation of power flow problems. The convergence characteristics and sparsity structure of the preconditioners are compared to the well-known black-box preconditioners such as incomplete LU and the results are presented.
Citation - WoS: 10
Citation - Scopus: 10
Two-Dimensional Inverse Quasilinear Parabolic Problem With Periodic Boundary Condition
(Taylor & Francis Ltd, 2019) Baglan, İrem Sakınç; Kanca, Fatma
In this study we consider a coefficient problem of a quasi-linear two-dimensional parabolic inverse problem with periodic boundary and integral over determination conditions. We prove the existence uniqueness and continuously dependence upon the data of the solution by iteration method. Also we consider numerical solution for this inverse problem by using linearization and the implicit finite-difference scheme.

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