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  1. Article ; Online: Current practices of craniospinal irradiation techniques in Turkey: a comprehensive dosimetric analysis.

    Şenkesen, Öznur / Tezcanlı, Evrim / Alkaya, Fadime / İspir, Burçin / Çatlı, Serap / Yeşil, Abdullah / Bezirganoglu, Ebrar / Turan, Sezgi / Köksal, Canan / Güray, Gülay / Hacıislamoğlu, Emel / Durmuş, İsmail Faruk / Çavdar, Şeyma / Aksu, Telat / Çolak, Nurten / Küçükmorkoç, Esra / Doğan, Mustafa / Ercan, Tülay / Karaköse, Fatih /
    Alpan, Vildan / Ceylan, Cemile / Poyraz, Gökhan / Nalbant, Nilgül / Kınay, Şeyda / İpek, Servet / Kayalılar, Namık / Tatlı, Hamza / Zhu, Mingyao

    Radiation oncology (London, England)

    2024  Volume 19, Issue 1, Page(s) 49

    Abstract: Objective: This study evaluates various craniospinal irradiation (CSI) techniques used in Turkish centers to understand their advantages, disadvantages and overall effectiveness, with a focus on enhancing dose distribution.: Methods: Anonymized CT ... ...

    Abstract Objective: This study evaluates various craniospinal irradiation (CSI) techniques used in Turkish centers to understand their advantages, disadvantages and overall effectiveness, with a focus on enhancing dose distribution.
    Methods: Anonymized CT scans of adult and pediatric patients, alongside target volumes and organ-at-risk (OAR) structures, were shared with 25 local radiotherapy centers. They were tasked to develop optimal treatment plans delivering 36 Gy in 20 fractions with 95% PTV coverage, while minimizing OAR exposure. The same CT data was sent to a US proton therapy center for comparison. Various planning systems and treatment techniques (3D conformal RT, IMRT, VMAT, tomotherapy) were utilized. Elekta Proknow software was used to analyze parameters, assess dose distributions, mean doses, conformity index (CI), and homogeneity index (HI) for both target volumes and OARs. Comparisons were made against proton therapy.
    Results: All techniques consistently achieved excellent PTV coverage (V95 > 98%) for both adult and pediatric patients. Tomotherapy closely approached ideal Dmean doses for all PTVs, while 3D-CRT had higher Dmean for PTV_brain. Tomotherapy excelled in CI and HI for PTVs. IMRT resulted in lower pediatric heart, kidney, parotid, and eye doses, while 3D-CRT achieved the lowest adult lung doses. Tomotherapy approached proton therapy doses for adult kidneys and thyroid, while IMRT excelled for adult heart, kidney, parotid, esophagus, and eyes.
    Conclusion: Modern radiotherapy techniques offer improved target coverage and OAR protection. However, 3D techniques are continued to be used for CSI. Notably, proton therapy stands out as the most efficient approach, closely followed by Tomotherapy in terms of achieving superior target coverage and OAR protection.
    MeSH term(s) Adult ; Humans ; Child ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted/methods ; Craniospinal Irradiation/methods ; Turkey ; Radiotherapy, Conformal/methods ; Radiotherapy, Intensity-Modulated/methods
    Language English
    Publishing date 2024-04-16
    Publishing country England
    Document type Journal Article
    ZDB-ID 2224965-5
    ISSN 1748-717X ; 1748-717X
    ISSN (online) 1748-717X
    ISSN 1748-717X
    DOI 10.1186/s13014-024-02435-4
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Two Different Points of View through Artificial Intelligence and Vector Autoregressive Models for Ex Post and Ex Ante Forecasting.

    Aydin, Alev Dilek / Caliskan Cavdar, Seyma

    Computational intelligence and neuroscience

    2015  Volume 2015, Page(s) 409361

    Abstract: The ANN method has been applied by means of multilayered feedforward neural networks (MLFNs) by using different macroeconomic variables such as the exchange rate of USD/TRY, gold prices, and the Borsa Istanbul (BIST) 100 index based on monthly data over ... ...

    Abstract The ANN method has been applied by means of multilayered feedforward neural networks (MLFNs) by using different macroeconomic variables such as the exchange rate of USD/TRY, gold prices, and the Borsa Istanbul (BIST) 100 index based on monthly data over the period of January 2000 and September 2014 for Turkey. Vector autoregressive (VAR) method has also been applied with the same variables for the same period of time. In this study, different from other studies conducted up to the present, ENCOG machine learning framework has been used along with JAVA programming language in order to constitute the ANN. The training of network has been done by resilient propagation method. The ex post and ex ante estimates obtained by the ANN method have been compared with the results obtained by the econometric forecasting method of VAR. Strikingly, our findings based on the ANN method reveal that there is a possibility of financial distress or a financial crisis in Turkey starting from October 2017. The results which were obtained with the method of VAR also support the results of ANN method. Additionally, our results indicate that the ANN approach has more superior prediction performance than the VAR method.
    MeSH term(s) Algorithms ; Artificial Intelligence ; Computer Simulation ; Forecasting ; Humans ; Neural Networks (Computer)
    Language English
    Publishing date 2015
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2388208-6
    ISSN 1687-5273 ; 1687-5265
    ISSN (online) 1687-5273
    ISSN 1687-5265
    DOI 10.1155/2015/409361
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: An empirical analysis for the prediction of a financial crisis in Turkey through the use of forecast error measures

    Cavdar, Seyma Caliskan / Aydin, Alev Dilek

    Journal of risk and financial management : JRFM Vol. 8, No. 3 , p. 337-354

    2015  Volume 8, Issue 3, Page(s) 337–354

    Abstract: In this study, we try to examine whether the forecast errors obtained by the ANN models affect the breakout of financial crises. Additionally, we try to investigate how much the asymmetric information and forecast errors are reflected on the output ... ...

    Author's details Seyma Caliskan Cavdar and Alev Dilek Aydin (Halic University, Faculty of Business)
    Abstract In this study, we try to examine whether the forecast errors obtained by the ANN models affect the breakout of financial crises. Additionally, we try to investigate how much the asymmetric information and forecast errors are reflected on the output values. In our study, we used the exchange rate of USD/TRY (USD), the Borsa Istanbul 100 Index (BIST), and gold price (GP) as our output variables of our Artificial Neural Network (ANN) models. We observe that the predicted ANN model has a strong explanation capability for the 2001 and 2008 crises. Our calculations of some symmetry measures such as mean absolute percentage error (MAPE), symmetric mean absolute percentage error (sMAPE), and Shannon entropy (SE), clearly demonstrate the degree of asymmetric information and the deterioration of the financial system prior to, during, and after the financial crisis. We found that the asymmetric information prior to crisis is larger as compared to other periods. This situation can be interpreted as early warning signals before the potential crises. This evidence seems to favor an asymmetric information view of financial crises.
    Keywords symmetry measurements ; forecast error measures ; asymmetric information ; artificial neural network ; machine learning ; Shannon entropy ; financial crisis
    Language English
    Size Online-Ressource
    Publisher MDPI
    Publishing place Basel
    Document type Article ; Online
    ZDB-ID 2739117-6
    ISSN 1911-8074 ; 1911-8066
    ISSN (online) 1911-8074
    ISSN 1911-8066
    DOI 10.3390/jrfm8030337
    Database ECONomics Information System

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  4. Article: Prediction of financial crisis with artificial neural network

    Aydın, Alev Dilek / Cavdar, Seyma Çalıskan

    International journal of financial research Vol. 6, No. 4 , p. 36-45

    an empirical analysis on Turkey

    2015  Volume 6, Issue 4, Page(s) 36–45

    Author's details Alev Dilek Aydın & Seyma Çalıskan Cavdar
    Keywords artificial neural network ; forecasting ; financial crisis ; ENCOG machine learning ; JAVA
    Language English
    Size graph. Darst.
    Publisher Sciedu Press
    Publishing place Toronto
    Document type Article
    ZDB-ID 2611282-6 ; 2611285-1
    ISSN 1923-4031 ; 1923-4023
    ISSN (online) 1923-4031
    ISSN 1923-4023
    Database ECONomics Information System

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  5. Article: A different perspective for current account deficit issue on some OECD member countries

    Cavdar, Seyma Caliskan / Aydin, Alev Dilek

    Research in world economy Vol. 6, No. 3 , p. 14-22

    a binary panel logit approach

    2015  Volume 6, Issue 3, Page(s) 14–22

    Author's details Seyma Caliskan Cavdar & Alev Dilek Aydin
    Keywords binary panel logit ; current account deficit ; financial crisis ; pre-crisis period ; fixed effect panel logit
    Language English
    Publisher Sciedu Press
    Publishing place Toronto
    Document type Article
    ZDB-ID 2647497-9 ; 2635432-9
    ISSN 1923-399X ; 1923-3981
    ISSN (online) 1923-399X
    ISSN 1923-3981
    Database ECONomics Information System

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  6. Article: TÜRKİYE'DE BÜTÇE AÇIKLARININ İKTİSADİ BÜYÜME VE İSTİKRAR ÜZERİNE ETKİLERİ (1994:Q1-2004:Q4)

    ÇAVDAR, Şeyma Çalışkan

    Elektronik Sosyal Bilimler Dergisi; Sayı: 37

    Abstract: Bu çalışmada, Türkiye'de 1994:Q1- 2004:Q4 dönemindeki bütçe açıklarındaki herhangi bir artışın ekonomik büyümeye etkisi araştırılmıştır. Araştırmada Geleneksel birim kök testinin (Augmented Dickey Fuller) yanı sıra, standart Granger nedensellik testi ... ...

    Abstract Bu çalışmada, Türkiye'de 1994:Q1- 2004:Q4 dönemindeki bütçe açıklarındaki herhangi bir artışın ekonomik büyümeye etkisi araştırılmıştır. Araştırmada Geleneksel birim kök testinin (Augmented Dickey Fuller) yanı sıra, standart Granger nedensellik testi uygulanmış, bütçe açıkları ve büyüme oranı arasında, bütçe açıklarından büyüme oranına doğru bir nedensellik ilişkisinin bulunduğu sonucuna varılmıştır ( . Elde edilen bu sonuç ise, Keynes'gil yaklaşımda "dışsal bir değişken" olarak kabul edilen kamu harcamalarının ekonomideki büyümeyi tetikleyici yönde etkileceği yönündeki görüşü desteklemesi bakımından ilginç bulunmuştur.
    Language Turkish
    Document type Article
    ISSN 1304-0278
    Database AGRIS - International Information System for the Agricultural Sciences and Technology

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