Yönetim Bilişim Sistemleri Bölümü Koleksiyonu

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

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Management Information Systems: the Virtual Team Scorecard (vts)
(2013) Oberer, Birgit; Erkollar, Alptekin
Organizations resisting changes are missing opportunities to grow or to become or remain competitive. Management Information Systems (MIS) used as decision support systems may support organizations in making use of changes in environmental conditions. Nevertheless innovative structures are needed to motivate organizations contributing in change projects. Tn this study a virtual team scorecard which can be used as a management information system enabling requirements analyses for managing virtual teams in organizations and in virtual teams with members of different organizations was developed in two different versions: (a) an intemal VTS and (b) an inter-organizational VTS. The results revealed that the developed virtual team scorecard covers all the main strategic factors from a management perspective and in particular relies on the qualitative factors of the team determines the quality and group dynamics deficits of a team and may provide clues for knowing which factors should receive special attention. Furthermore the developed scorecard can be used for inter-organizational teams and any kind of structured co-operation between organizations.
On the Selection of Interpolation Points for Rational Krylov Methods
(Springer-Verlag Berlin, 2012) Yetkin, E. Fatih; Dağ, Hasan
We suggest a simple and an efficient way of selecting a suitable set of interpolation points for the well-known rational Krylov based model order reduction techniques. To do this some sampling points from the frequency response of the transfer function are taken. These points correspond to the places where the sign of the numerical derivation of transfer function changes. The suggested method requires a set of linear system's solutions several times. But they can be computed concurrently by different processors in a parallel computing environment. Serial performance of the method is compared to the well-known H-2 optimal method for several benchmark examples. The method achieves acceptable accuracies (the same order of magnitude) compared to that of H-2 optimal methods and has a better performance than the common selection procedures such as linearly distributed points.
Citation - WoS: 11
Mobile Learning in Higher Education: a Marketing Course Design Project in Austria
(Elsevier Science Bv, 2013) Oberer, Birgit; Erkollar, Alptekin
The course concept introduced in this paper was implemented in 2011 in a university in Austria and shows an approach for integrating mobile learning modules in higher education. The results of the course as revealed in the research show the advantages as well as the potential for improvement of the system and its use in higher education. (C) 2013 The Authors. Published by Elsevier Ltd.
Graph Optimized Locality Preserving Projection Via Heuristic Optimization Algorithms
(IEEE, 2019) Ceylan, Oğuzhan; Taşkın, Gülşen
Dimensionality reduction has been an active research topic in hyperspectral image analysis due to complexity and non-linearity of the hundreds of the spectral bands. Locality preserving projection (LPP) is a linear extension of the manifold learning and has been very effective in dimensionality reduction compared to linear methods. However, its performance heavily depends on construction of the graph affinity matrix, which has two parameters need to be optimized: k-nearest neighbor parameter and heat kernel parameter. These two parameters might be optimally chosen simply based on a grid search when using only one representative kernel parameter for all the features, but this solution is not feasible when considering a generalized heat kernel in construction the affinity matrix. In this paper, we propose to use heuristic methods, including harmony search (HS) and particle swarm optimization (PSO), in exploring the effects of the heat kernel parameters on embedding quality in terms of classification accuracy. The preliminary results obtained with the experiments on the hyperspectral images showed that HS performs better than PSO, and the heat kernel with multiple parameters achieves better performance than the isotropic kernel with single parameter.
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.
Sustainable and Responsible Business: the Renewed Eu Strategy 2011-2014 for Corporate Social Responsibility
(Int Business Information Management Assoc-IBIMA, 2012) Erkollar, Alptekin; Oberer, Birgit
Corporate social responsibility (CSR) refers to companies that voluntarily go beyond what the law requires in order to achieve social and environmental objectives during the course of their daily business activities. The European Commission encourages companies to apply fair employment practices that respect human rights particularly where products come from outside the EU. In this contribution the activities of the European Union on Corporate Social Responsibility are analyzed focusing on the 2011-2014 strategy on Corporate Social Responsibility which was published in 2011 and corporate social responsibility reporting and disclosure. The results of the analysis revealed that the European Commission by publishing their new policy on corporate social responsibility intends to enhance positive and to minimize and prevent negative impacts in close collaboration with their stakeholders addressing different actions such as the establishment of sector-based platforms for enterprises and stakeholders to make commitments and jointly monitor progress. The promotion of social and environmental responsibility through the supply-chain and the disclosure of non-financial information are recognised as important cross-cutting issues. Regarding the disclosure the European Commission has different open issues to work on to get a working process for reaching sustainable and responsible businesses.
Citation - WoS: 2
Citation - Scopus: 2
Determination of a Diffusion Coefficient in a Quasilinear Parabolic Equation
(De Gruyter Open Ltd, 2017) Kanca, Fatma
This paper investigates the inverse problem of finding the time-dependent diffusion coefficient in a quasilinear parabolic equation with the nonlocal boundary and integral overdetermination conditions. Under some natural regularity and consistency conditions on the input data the existence uniqueness and continuously dependence upon the data of the solution are shown. Finally some numerical experiments are presented.
Citation - WoS: 14
Citation - Scopus: 18
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: 6
Citation - Scopus: 9
Assessment of Harmonic Distortion on Distribution Feeders With Electric Vehicles and Residential Pvs
(IEEE, 2017) Ceylan, Oğuzhan; Paudyal, Sumit; Dahal, Sudarshan; Karki, Nava R.
Power-electronic interfacing based devices such as photovoltaic (PV) panels and electric vehicles (EVs) cause voltage/current harmonic distortions on the power grid. The harmonic current profiles from EVs and PVs depend on the design of the controllers integrated to the PV inverters and EV chargers. Similarly the voltage and current harmonic distortions on a grid change throughout the day as the PV output power number of grid connected EVs and the other load pattern change. In this context we present harmonic assessment to demonstrate cumulative effect of large number of EVs and PVs on a medium voltage distribution grid. We will demonstrate the case studies on the IEEE 123-node distribution feeder with 20% 50% and 100% PV and EV penetrations based on time series simulations carried out for an entire day.
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: 3
Citation - Scopus: 6
Machine Learning Model To Predict an Adult Learner's Decision To Continue Esol Course or Not
(Springer, 2019) Dahman, Mohammed R.; Dağ, Hasan
This study investigated the ability of the demographic and the affective variables to predict the adult learners' decision to continue ESOL courser. 278 adult learners, enrolled on ESOL course at FLS institution in Istanbul, Turkey, participated in the study. The result showed that the continued or dropped out groups, demonstrated statistical differences in the demographic variable (the placement test score) with a magnitude of large effect size (.378). Additionally, the result showed the effect size in the perception of the affective variables (motivation, attitude, and anxiety), accounts for about 50% of the variation between the continuation and dropout groups. Following that, three machine learning models were proposed; all possible subset regression analysis was used to compare the three models. The adequate model, which fitted the demographic variable (the placement test score) and the affective variables (motivation, attitude, and anxiety), correctly predicted 83.3% of the adult learners' decision to continue ESOL course. The model showed about 68% goodness-of-fit. The cultural implications of these findings are discussed, along with suggestions for future research.
Citation - WoS: 1
Citation - Scopus: 1
School-wide friendship metadata correlations
(Pergamon-Elsevier Science Ltd, 2019) Aydın, Mehmet Nafiz; Perdahçı, Nazım Ziya
Managers and education practitioners desire to know an extent to which sustainable school-wide friendship exists. Drawing on theory of network this research focuses on bestfriendships that may contribute to positive school experience or school belonging in the context of school-wide interactions. We emphasize that school-wide unity is essential to refer to shared perceived friendship experience at the school level. The basic trust of this study is that managers should consider interconnectedness as a complex system of entangled interactions among students. We investigate best friendship network on the meso-to-macro scale. Particular attention is paid to the network phenomena of the largest component and network correlations for examining school wide unity. The results show that abundance of asymmetric friendships leads to unity around school wide interactions. As suggested by network theory popular students' tendency to avoid forming closed clusters assures sustainability in school-wide friendships and having same gender type or being classmates correlate highly with the choice of best friends in contrast to achievement scores. Metadata correlations reveal same-gender and same-class clubs. Incorporating meso level findings into macro level indicates that some metadata (e.g. gender) may be considered as salient characteristics of the communities while other metadata (e.g. achievement scores) may be irrelevant.
Citation - WoS: 4
Project Management Method Adoption: a Service Industry Case Study
(IGI Global, 2017) Aydın, Mehmet Nafiz; Dilan, Ebru
The purpose of this research is to understand what aspects of brand-named project management method (Project Management Institute - PMI) have been adopted in a service organization and how. The case context examined demonstrates how a weak-matrix organizational structure and agency interpretation along with project management maturity for IT outsourcing projects can affect adoption of a project management method. An interpretative case study is employed for examining the interplays among key notions underlying project management method adoption in IT outsourcing projects. The case study is framed with a research logic constituting the underlying notions of method adoption: the context the agency and the method and its fragments. It is found that the organization realizes 43 out of 47 processes proposed by PMI. It is also observed that the perceived project management maturity level is not aligned with the method fragments adopted. Among other discussion points the present findings contribute to the existing literature by emphasizing the effects of management control on PM method adoption in IT outsourcing. Furthermore this case allows us to argue that product-focused orientation in project management method adoption is evident and has several implications. The adoption and adaptation of processes in different types of projects is on the authors' future research agenda.
Citation - Scopus: 1
National Electronic Government Strategies in Austria
(ACAD Conferences Ltd, 2011) Oberer, Birgit; Erkollar, Alptekin
One of the most emerging concepts of information technology is the one of electronic government. Electronic services that are made available by governments to citizens businesses and other governments (international) or governmental authorities (national) are general proof of the changes being made in the public sector. Intersecting the government citizen and business domain a business model can be defined considering the government-to-business government-to-citizen and government-to-government approaches. Governments around the world try to follow their most of the time ambitious strategies to become or stay competitive. In this study Austrian strategies and projects for electronic government as well as their implementation plans were analysed followed by an examination of the electronic services offered by the national governmental authorities in Austria one pioneer in electronic government in Europe leading in the European E-Government ranking 2010 and the declared 'European champion in eGovernment' for the fourth time in a row. The results revealed that Austria has developed hybrid electronic government strategies and has launched projects in that field in which national governmental authorities have to participate in order to offer electronic government services at a high level and in a competitive international environment. On a whole offering a one-stop shop gateway to governmental information and transactions generally offers higher attractiveness for conducting nationwide business and all incentives for electronic government focus on developing good practices in the area of efficient and effective electronic government. Nevertheless national strategies are transformed and implemented in different ways not always following the one-stop-shop approach and contributing to the development of isolated applications instead of integrated ones.
Analysis and Implications of the Giant Component for an Online Interactive Platform
(Int Business Information Management Assoc-IBIMA, 2016) Aydın, Mehmet Nafiz; Perdahci, N. Ziya
This research is concerned with practical and research challenges related to understanding the nature of online interactive platforms. So-called network science is adopted to investigate the very nature of these systems as complex systems. In this regard we examine an online interactive health network and show that the interactive platform examined exhibits essential structural properties that characterize most real complex networks. We basically look into the largest connected component so-called a giant component (GC) to better understand how the representative network has established. In particular we apply dynamic network analysis to investigate how the GC has evolved over time. We identify a particular pattern towards emerging a GC. Implications of the patterns have been elaborated from a management perspective. We recommend that the basic stages of the emergence of the GC might be of interest to platform managers while evaluating performance of online platforms.
Innovation in Management: the Virtual Project Performance Scorecard (vpps)
(INFORMATION ENGINEERING RESEARCH INST USA, 2013) Oberer, Birgit; Erkollar, Alptekin
Many organizations that resist change are missing growing opportunities
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.
Post-outage state estimations for outage management
(IFAC Secretariat, 2011) Ceylan, Oğuzhan; Ozdemir, Aydogan; Dağ, Hasan
Real time outage information is required to the utility operators for outage management process. In addition to some basic information regarding the outage post-outage system status will help to improve the response to outages and management of system reliability. This paper presents particle swarm optimization based reactive power estimations for branch outages. Post outage voltage magnitudes and reactive power flows results for IEEE 14 and IEEE 30 bus systems are given. Simulation results show that post outage voltage magnitudes and reactive power flows can be computed with a reasonable accuracy. © 2011 IFAC.
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 - Scopus: 3
A Comparative Study of Surrogate Based Learning Methods in Solving Power Flow Problem
(IEEE, 2020) Ceylan, Oğuzhan; Taşkın, Gülsen; Paudyal, Sumit
Due to increasing volume of measurements in smart grids, surrogate based learning approaches for modeling the power grids are becoming popular. This paper uses regression based models to find the unknown state variables on power systems. Generally, to determine these states, nonlinear systems of power flow equations are solved iteratively. This study considers that the power flow problem can be modeled as an data driven type of a model. Then, the state variables, i.e., voltage magnitudes and phase angles are obtained using machine learning based approaches, namely, Extreme Learning Machine (ELM), Gaussian Process Regression (GPR), and Support Vector Regression (SVR). Several simulations are performed on the IEEE 14 and 30-Bus test systems to validate surrogate based learning based models. Moreover, input data was modified with noise to simulate measurement errors. Numerical results showed that all three models can find state variables reasonably well even with measurement noise.

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