Ayşe Demirhan

Performance Evaluation of the Machine Learning Algorithms Used in Inference Mechanism of a Medical Decision Support System

The importance of the decision support systems is increasingly supporting the decision making process in cases of uncertainty and the lack of information and they are widely used in various fields like engineering, finance, medicine, and so forth, Medical decision support systems help the healthcare personnel to select optimal method during the treatment of the patients. Decision support systems are intelligent software systems that support decision makers on their decisions. The design of decision support systems consists of four main subjects called inference mechanism, knowledge-base, explanation module, and active memory. Inference mechanism constitutes the basis of decision support systems. There are various methods that can be used in these mechanisms approaches. Some of these methods are decision trees, artificial neural networks, statistical methods, rule-based methods, and so forth. In decision support systems, those methods can be used separately or a hybrid system, and also combination of those methods. In this study, synthetic data with 10, 100, 1000, and 2000 records have been produced to reflect the probabilities on the ALARM network. The accuracy of 11 machine learning methods for the inference mechanism of medical decision support system is compared on various data sets.

Creating Competitive Advantage by Using Data Mining Technique as an Innovative Method for Decision Making Process in Business

Orientarea organizatiilor spre marketingul relational a adus in prim plan trei concepte a caror importanta a crescut semnificativ in ultimul deceniu: atragerea, retentia si recastigarea clientilor pierduti. In mod firesc, se prefigureaza intrebarea privind gradul de prioritate al atragerii si respectiv al mentinerii clientilor. Raspunsul corect nu trebuie sa contrapuna cele doua laturi ale aceluiasi proces de dezvoltare a valorii fluxurilor viitoare de profit generate de portofoliul de clienti al organizatiei. In esenta, fiecare organizatie trebuie sa realizeze simultan demersuri pentru atragerea si retentia clientilor, investind insa un volum diferit de resurse in fiecare dintre cele doua arii, in functie de stadiul de evolutie al organizatiei, produsului/marcii si pietei. Optiunile managerilor si specialistilor de marketing se pot indrepta spre strategii ofensive, de atragere a unor noi clienti, sau spre strategii defensive, de mentinere a clientilor actuali.

Is Really Debt a Man's Whip?☆

Abstract There is a growing concern for ever increasing external debt stock of countries in the worldwide. Coupled with resent global crises, the sustainability and efficient use of external debt becomes more and more important. To this end, we have tested the hypothesis of external debt led growth hypothesis for the case of Turkish economy. Our result has confirmed that Turkeys external debt both sustainable and efficiently used, at least for the last decade or so. The overall result proves also the reality of Turkish proverb “debt is a mans whip”.

Analysis of changes in market shares of commercial banks operating in turkey using computational intelligence algorithms

This paper aims to model the change in market share of 30 domestic and foreign banks, which have been operating between the years 1990 and 2009 in Turkey by taking into consideration 20 financial ratios of those banks. Due to the fragile structure of the banking sector in Turkey, this study plays an important role for determining the changes in market share of banks and taking the necessary measures promptly. For this reason, computational intelligence methods have been used in the study. According to the research results, it is seen that it was not able to properly anticipate the data for the banking sector in the periods of financial crises (2000-2001 and 2008-2009). However, it is seen that, Simple Linear Regression is distinguished as a good algorithm among the computational intelligence algorithms for all periods between the years 1990 and 2009.

İçsel Güdülenme Envanteri Dilsel Eşdeğerlik, Güvenirlik ve Geçerlik Çalışması

Bu arastirmanin amaci, Ryan’in ilk kez 1982 yilinda gelistirdigi Icsel Gudulenme Envanteri’nin (IGE) “Intrinsic Motivation Inventory (IMI)” Turkiye dilsel esdegerlik, guvenirlik ve gecerlik calismasini yapmaktir. Bu arastirmada veriler Istanbul’da bulunan iki ayri universitenin farkli bolumlerinde ogrenim goren ogrencilerden (N=320) toplanmistir. Arastirmada test-tekrar test calismasi icin bu orneklemden 42 kisinin verilerinden yararlanilmistir. Bu orneklemin disinda, arastirmanin olcut gecerligi calismasi icin Kultur Universitesi ogrencisi 40 kisiye iki ayri gudulenme envanteri uygulanmistir. Icsel Gudulenme Envanteri (IGE) dilsel esdegerlik, guvenirlik ve gecerlik calismasinda yontem olarak Faktor Analizi ve Korelasyon uygulanmistir. Arastirma, oncelikle dilsel esdegerlik calismasiyla baslamistir. Arastirmanin guvenirlik calismasinda, envanterin test-tekrar test uygulamasi yapilmistir. Ayni olcegin iki farkli zamanda uygulamasi arasinda fark olup olmadigi “Iliskili Orneklemler Icin t-test” ile olculmustur. IGE’nin test-tekrar test guvenirlik katsayisi hesaplanmis ve anlamli iliski gorulmustur. Faktor analizinde de anlamli degerler elde edilmistir. IGE’nin yapi gecerliginin bir baska boyutu olan ic tutarlilik analizinde, olcegin alt olcek ve toplami arasinda pozitif yonde anlamli iliskiler bulunmustur. IGE’nin gecerlik calismasinda son olarak, olcut gecerligi analizinde anlamli iliski elde edilmistir. IGE dilsel esdegerlik, guvenirlik ve gecerlik calismasi sonucunda icsel gudulenme boyutlarini olcebilmektedir.