İşletme Fakültesi

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Citation - WoS: 1
Citation - Scopus: 1
Analysis of the Patients and Physicians Connection Network on an Online Health Information Platform
(IOS Press, 2014) Aydın, Mehmet Nafiz; Perdahci, N. Ziya
Social network applications have gained popularity in the health domain as they bring health information seekers (patients and alike) and medication advice providers (physicians and other relevant actors) together. By employing a network science perspective this research is aimed to understand an information network establishing connections among and between information seekers and providers. We found that such a connection network surfaces most of the essential characteristics of a typical complex network. Furthermore a detailed structural analysis shows some intriguing relations and connection behaviours in the network. Implications of the findings are discussed from the perspectives of medical informatics and social network analysis.
Citation - WoS: 2
Citation - Scopus: 6
Branch Outage Simulation Based Contingency Screening by Gravitational Search Algorithm
(Praise Worthy Prize Srl, 2012) Ceylan, Oğuzhan; Özdemir, Aydoğan; Dağ, Hasan
Power systems contingency analysis is an important issue for electric power system operators. This paper performs branch outage simulation based contingency screening using a bounded network approach. Local constrained optimization problem representing the branch outage phenomena is solved by the gravitational search algorithm. The proposed method is applied to IEEE 14 30 57 and 118 Bus Test systems and its performance from the point of capturing violations is evaluated. In addition false alarms and the computational accuracy of the proposed method are also analyzed by using scattering diagrams. Finally the proposed gravitational search based contingency screening is compared with full AC load flow solutions from the point of computational speed. Copyright (C) 2012 Praise Worthy Prize S.r.l. - All rights reserved.
A Characterization of Totally Umbilical Hypersurfaces of a Space Form by Geodesic Mapping
(Springer, 2013) Canfes, Elif Ozkara; Özdeğer, Abdülkadir
The idea of considering the second fundamental form of a hypersurface as the first fundamental form of another hypersurface has found very useful applications in Riemannian and semi-Riemannian geometry especially when trying to characterize extrinsic hyperspheres and ovaloids. Recently T. Adachi and S. Maeda gave a characterization of totally umbilical hypersurfaces in a space form by circles. In our paper we give a characterization of totally umbilical hypersurfaces of a space form by means of geodesic mapping.
Citation - Scopus: 6
A Country-Specific Analysis on Internet Interconnection Ecosystems
(IEEE, 2018) Cakmak, Gorkem; Aydın, Mehmet Nafiz
With the proliferating number of diverse participants and destinations to reach the Internet construct has become more intricate to assay. Today Internet Service Providers (ISPs) establish resilient networks from multiple providers and broaden the number of peering links-as financially as viable. However the complex structure of the global Internet ecosystem and entwined roles of Internet players simply prevent us from conducting generalized models for grasping interconnections which could be applied globally regardless of the local surroundings. In this paper the global inter-domain Internet topology is scrutinized by the help of interconnection characteristics within a country-specific stance. Our study on the Internet ecosystems helps us highlight the non-uniformity of interconnections by using both 'real world' metrics and network science metrics. One of the significant findings that the analysis yields is that presence of well-established Internet Exchange Points (IXPs) in an interconnection ecosystem-besides the benefit of bolstering the peering fabric-increases the competitive nature of Internet transit market and boosts the inclination to multihome for stub networks thus increases the resilience of national Internet constructs. © 2017 IEEE.
Citation - WoS: 2
A Country-Specific Analysis on Internet Interconnection Ecosystems
(IEEE, 2017) Çakmak, Görkem; Aydın, Mehmet Nafiz
With the proliferating number of diverse participants and destinations to reach, the Internet construct has become more intricate to assay. Today, Internet Service Providers (ISPs) establish resilient networks from multiple providers and broaden the number of peering links - as financially as viable. However, the complex structure of the global Internet ecosystem and entwined roles of Internet players simply prevent us from conducting generalized models for grasping interconnections which could be applied globally regardless of the local surroundings. In this paper, the global inter-domain Internet topology is scrutinized by the help of interconnection characteristics within a country-specific stance. Our study on the Internet ecosystems helps us highlight the non-uniformity of interconnections by using both "real world" metrics and network science metrics. One of the significant findings that the analysis yields is that presence of well-established Internet Exchange Points (IXPs) in an interconnection ecosystem - besides the benefit of bolstering the peering fabric - increases the competitive nature of Internet transit market and boosts the inclination to multi-home for stub networks, thus increases the resilience of national Internet constructs.
Citation - WoS: 1
Citation - Scopus: 1
A Critical Analysis of Current Legal Developments on the Political Participation of Minorities in Turkey
(2010) Akbulut, Olgun
This is a follow-up article to the one published in the IJMGR half a decade ago (Vol. 12 2005). Although there have been domestic and international legal cases that are directly concerned with the political participation of minorities in Turkey few improvements have been made in law covering the subject. This encouraged this author to analyse and criticise the judgements of the European Court of Human Rights and the legal and political actors at domestic level. The aim of this article is to reflect upon how international human rights monitoring affects national laws in certain thorny issues such as the rights of minorities. Since the current and previous articles have a common theme and complement each other I strongly recommend reading both articles. © 2010 Martinus Nijhoff Publishers.
Citation - Scopus: 1
Distributed Memory Parallel Transient Stability Analysis on a Pc Cluster With Ethernet
(Praise Worthy Prize Srl, 2010) Soykan, Gürkan; Flueck, Alexander J.; Dağ, Hasan
On-line transient stability analysis is a necessity for real-time power system control and security. Parallel processing is a natural technology for achieving real-time solution performance. This paper presents a parallel-in-space algorithm based on a multi-level partitioning scheme in a distributed memory cluster environment. The main aim of the research is to decrease the wallclock time of transient stability analysis of large scale power systems by leveraging open source software and commodity off the shelf hardware of a Linux PC cluster. The proposed solution algorithm focuses on speeding up the transient stability simulation by partitioning via METIS the linearized update solution process of the Very Dishonest Newton Method for solving the differential-algebraic equation system. Results are presented for two power systems: I) 3493 buses 844 generators 6689 branches and 2) 7935 buses 2135 generators 13624 branches. The simulations were run on a small Linux-cluster with a 100 Mbit/s ethernet interconnect which is cheaper than any specially constructed parallel computer. By tuning vertex weights the performance of the partition strategy can be improved relative to the no-weight case. The proposed method easily can be adapted by commercial packages and used in various parallel environments including multicore architectures with non-uniform memory access. Copyright (C) 2010 Praise Worthy Prize S.r.l. - All rights reserved.
Citation - Scopus: 11
Exploring Competitive Intelligence Practices of French Local Public Agricultural Organisations
(Halmstad University, 2014) Bisson, Christophe
Modern agriculture has increased the need for information when making strategic decisions for farmers since they must be more entrepreneurial to survive. This paper investigates the levels of Competitive Intelligence practices in a French Regional Chamber of Agriculture and its four Departmental Chambers of Agriculture to examine the ability of these public organisations to keep fulfilling one of their missions which is to provide the necessary information and knowledge to farmers. Thus this study proposes a behavioural and operational typology of Competitive Intelligence practice. Both types of organisations demonstrate that they are not well adapted to support the entrepreneurial farmers on this issue. The findings of this study and the diagnosis of the Competitive Intelligence practices applied to the typology could be of help to increase their and other public agricultural structures performance levels. Furthermore the platform has the potential to inspire the public sector through subsequent adaptations.
Citation - WoS: 14
Citation - Scopus: 19
Inverse Coefficient Problem of the Parabolic Equation With Periodic Boundary and Integral Overdetermination Conditions
(Hindawi Publishing Corporation, 2013) Kanca, Fatma
This paper investigates the inverse problem of finding a time-dependent diffusion coefficient in a parabolic equation with the periodic boundary and integral overdetermination conditions. Under some assumption on the data the existence uniqueness and continuous dependence on the data of the solution are shown by using the generalized Fourier method. The accuracy and computational efficiency of the proposed method are verified with the help of the numerical examples.
The “karakoncolos/kalikancaros” belief in Turkish and Greek sources [Türkçe ve yunanca kaynaklarda karakoncolos/kalikancaros inancı]
(Milli Folklor Dergisi, 2018) Şişmanoğlu Şimşek, Şehnaz
The belief in “karakoncolos/kalikancaros” is seen in a wide geography spreading from Central Anatolia and Black Sea region in Turkey to Balkan Peninsula including Greece Bulgaria and Serbia. Though karakoncolos is defined under different names in Turkish sources the period it is depicted and its features are almost similar. According to this the karakoncolos believed to have emerged on the coldest days of the year is depicted as a creature that is often hairy resembling animal haunting people and disturbing them. One of the first written sources in Turkish that included the belief in karakoncolos is Evliya Çelebi’s Seyahatnâme. Today it is rarely a tradition in games such as “karakoncilo” in the Eastern Black Sea or a belief that has been almost forgotten or even unknown by the majority even though it continues to exist as a trivial image in Turkish literature and cinema. On the other hand this belief often referred to as kalikancaros in Greek was compiled by the folklorist Nikolaos Politis at an early date (1904). In this study first of all referring to the various beliefs concerning kalikancaros in the mentioned compilations of Politis the rewritings of them in the present Greek children’s literature by Filippos Mandilaras will be introduced. In today’s Greece it will be revealed that especially during the Christmas period it continues to exist as a popular figure of the musical performances in schools and in children’s books. When we have a look at the Turkish and Greek compilations of this belief in general which is spread over a wide geographical area we can see that the reviewed Turkish sources are mostly collected from the Eastern Black Sea region and rarely lived as an almost forgotten tradition. Today in Greece also due to the Velloudios’ paintings which still circulate today the mentioned belief continues to exist as a “national” and a popular element of the childrens’ literature. © 2019 Milli Folklor Dergisi. All rights reserved.
Citation - Scopus: 26
Land Use and Land Cover Classification of Sentinel 2-A: St Petersburg Case Study
(International Society for Photogrammetry and Remote Sensing, 2019) Çavur, Mahmut; Düzgün, Hafize Şebnem; Kemeç, Serkan; Demirkan, Doğa Çağdaş
Land use and land cover (LULC) maps in many areas have been used by companies, government offices, municipalities, and ministries. Accurate classification for LULC using remotely sensed data requires State of Art classification methods. The SNAP free software and ArcGIS Desktop were used for analysis and report. In this study, the optical Sentinel-2 images were used. In order to analyze the data, an object-oriented method was applied: Supported Vector Machines (SVM). An accuracy assessment is also applied to the classified results based on the ground truth points or known reference pixels. The overall classification accuracy of 83,64% with the kappa value of 0.802 was achieved using SVM. The study indicated that of SVM algorithms, the proposed framework on Sentinel-2 imagery results is satisfactory for LULC maps.
Citation - WoS: 1
Citation - Scopus: 2
The Maximum Surplus in a Finite-Time Interval for a Discrete-Time Risk Model With Exchangeable Dependent Claim Occurrences
(John Wiley and Sons Ltd, 2019) Gebizlioğlu, Ömer Lütfi; Eryilmaz, Serkan
This paper investigates a discrete-time risk model that involves exchangeable dependent loss generating claim occurrences and compound binomially distributed aggregate loss amounts. First a general framework is presented to derive the distribution of a surplus sequence using the model. This framework is then applied to obtain the distribution of any function of a surplus sequence in a finite-time interval. Specifically the distribution of the maximum surplus is obtained under nonruin conditions. Based on this distribution the computation of the minimum surplus distribution is given. Asset and risk management–oriented implications are discussed for the obtained distributions based on numerical evaluations. In addition comparisons are made involving the corresponding results of the classical discrete-time compound binomial risk model for which claim occurrences are independent and identically distributed. © 2018 John Wiley & Sons Ltd.
Citation - WoS: 2
Citation - Scopus: 2
A New Preconditioner Design Based on Spectral Division for Power Flow Analysis
(Praise Worthy Prize Srl, 2011) Dağ, Hasan; Yetkin, E. Fatih; Manguoglu, Murat
Solution of large sparse linear systems is the most lime consuming part in many power system simulations. Direct solvers based on LU factorization although robust are known to have limited satiability on parallel platforms. Thus. Krylov subspace based iterative methods (i.e. Conjugate Gradient method Generalized Minimal Residuals (GMRES) method) can be used as alternatives. To achieve competitive performance and robustness however the Krylov subspace methods need a suitable preconditioner. In this work we propose a new preconditioner iterative methods which can be used in Newton-Raphson process of power flow analysis. The suggested preconditioner employs the basic spectral divide and conquer methods and invariant subspaces for clustering the eigenvalues of the Jacobian matrix appearing in Newton-Raphson steps of power flow simulation. To obtain the preconditioner we use Matrix Sign Function (MSF) and to obtain the MSF itself we use Sparse Approximate Inverse (SPAI) algorithm with Newton iteration. We compare the convergence characteristics of our preconditioner against the well-known black-box preconditioners such as incomplete-LU and SPAI. Copyright (C) 2011 Praise Worthy Prize S.r.l. - All rights reserved.
Citation - WoS: 7
Citation - Scopus: 7
Personality Motivation and Math Achievement Among Turkish Students: Evidence From Pisa Data
(Sage Publications Inc, 2017) Akben Selçuk, Elif
Using the Turkish portion of the Programme for International Student Assessment dataset (N=4848
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 - WoS: 2
Traditional Folklore Forms in Temasa-I Dunya Ve Cefakar U Cefakes
(Milli Folklor Dergisi, 2016) Şişmanoğlu Şimşek, Şehnaz
Temasa-i Dunya ve Cefakar u Cefakes written by Evangelinos Misailidis in 1871-1872 has widely been considered to be an adaptation of the Greek novel O Polipathis (1839) and its originality has not been adequately emphasized in past studies. This article suggests that Temasa-i Dunya should be considered an original novel since it incorporates traditional folklore forms peculiar to Ottoman literature which are absent in Polipathis. This study first of all describes the variety and the origins of the traditional folklore forms in Temasa-i Dunya and delineates the literary tools by the help of which they were included in the text. Furthermore it analyzes how these elements affect the narrative discourse and the author's purposes in employing them. The analysis demonstrates that in Temasa-i Dunya oral and print culture materials of both Muslim and non-Muslim origins are embedded in the text primarily in the form of narrative digressions and digressions from the frame story. These digressions carry the marks of the traditional story teller both in terms of functionality and at the discursive level. In other words Misailidis' narrator being an active subject similar to the story teller in the oral culture chooses and manipulates the appropriate traditional story in accordance with the messages he conveys to the Karamanli readership. It can also be said that unrealistic features of traditional stories are eliminated and the stories are presented in a realistic style and content. Moreover the aforementioned narratives help to overcome the limited perspective of the first person narrative and to portray a variety of experiences. Temasa-i Dunya also presents a folkloric panorama of 19th century Istanbul through numerous idioms and proverbs.
Traditional Folklore Forms İn Temaşa-i Dünya ve Cefakar-u Cefakeş [temaşa-i Dünya ve Cefakar-u Cefakeş´te Geleneksel Folklor Biçimleri]
(Milli Folklor Dergisi, 2016) Şişmanoğlu Şimşek, Şehnaz
Temaşa-i Dünya ve Cefakâr u Cefakeş written by Evangelinos Misailidis in 1871-1872 has widely been considered to be an adaptation of the Greek novel O Polipathis (1839) and its originality has not been adequately emphasized in past studies. This article suggests that Temaşa-i Dünya should be considered an original novel since it incorporates traditional folklore forms peculiar to Ottoman literature which are absent in Polipathis. This study first of all describes the variety and the origins of the traditional folklore forms in Temaşa-i Dünya and delineates the literary tools by the help of which they were included in the text. Furthermore it analyzes how these elements affect the narrative discourse and the author’s purposes in employing them. The analysis demonstrates that in Temaşa-i Dünya oral and print culture materials of both Muslim and non-Muslim origins are embedded in the text primarily in the form of narrative digressions and digressions from the frame story. These digressions carry the marks of the traditional story teller both in terms of functionality and at the discursive level. In other words Misailidis’ narrator being an active subject similar to the story teller in the oral culture chooses and manipulates the appropriate traditional story in accordance with the messages he conveys to the Karamanli readership. It can also be said that unrealistic features of traditional stories are eliminated and the stories are presented in a realistic style and content. Moreover the aforementioned narratives help to overcome the limited perspective of the first person narrative and to portray a variety of experiences. Temaşa-i Dünya also presents a folkloric panorama of 19th century Istanbul through numerous idioms and proverbs.

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