48 results on '"PREDICTION models"'
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2. Egzersiz Yapma Sıklığı ve Bilinçli Farkındalığın Psikolojik iyi Oluş Üzerindeki Yordayıcı Etkisi: Tanımlayıcı Araştırma.
- Author
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ÇELİK, Nurullah and AKGÜN, Nurdan
- Subjects
EXERCISE physiology ,PREDICTION models ,MINDFULNESS ,STATISTICAL sampling ,AGE distribution ,DESCRIPTIVE statistics ,RESEARCH methodology ,WELL-being ,REGRESSION analysis ,EVALUATION - Abstract
Copyright of Turkiye Klinikleri Journal of Sports Sciences is the property of Turkiye Klinikleri and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
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- View/download PDF
3. Sürekli mıknatıslı senkron motorların hız-algılayıcısız model öngörülü akım kontrolü.
- Author
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Demir, Rıdvan and Gümüşcü, Duygu
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PREDICTIVE control systems , *PERMANENT magnet motors , *KALMAN filtering , *ANGULAR velocity , *PREDICTION models - Abstract
Permanent magnet synchronous motors (PMSMs) are widely used in industrial applications and electric vehicles which require high-performance variable torque and speed due to their high efficiency, simple structure, and wide speed range. In this study, an extended complex Kalman filter (ECKF) based observer is designed for simultaneous estimation of the load torque with the stator stationary axis components of stator currents and rotor angular velocity/position required for speed-sensorless model predictive current control of PMSMs. The designed ECKF observer and model predictive current control system has been tested and validated with challenging scenarios under different load torques in a wide speed range including zero speed and speed reversals. In addition, the performance of both the ECKF and the model predictive current control system is analyzed against parameter changes PMSM. The simulation results confirm that the ECKF observer and the speed-sensorless model predictive current control system using this observer have very high performance. In addition, the computational burden of the ECKF observer was compared with the conventional extended Kalman filter, which estimates the states and parameters estimated in this study, and it was shown that the processing computational burden decreased. [ABSTRACT FROM AUTHOR]
- Published
- 2025
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4. EĞİTİM YÖNETİCİLERİNİN KARİYER BAŞARILARININ SIRRI: SINIRSIZ VE ÇOK YÖNLÜ KARİYER YOLUYLA DEMOGRAFİK DEĞİŞKENLERİN GÜCÜNÜN KEŞFİ.
- Author
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SÖNER, Osman, DÜNDAR, Ferhat, KOŞAR, Mehmet, ŞARLAYAN, Gökhan, ECE, Fatih, and KANGAL, Yakup
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OCCUPATIONAL achievement ,REGRESSION analysis ,PREDICTION models ,ACQUISITION of data ,RESEARCH teams - Abstract
Copyright of Journal of Management Theory & Practices Research (JMTPR) is the property of Journal of Management Theory & Practices (JMTP) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2023
5. Pediatrik Behçet Hastalarında Ek İmmünsüpresif Tedavi Gereksiniminin Tahmin Edilmesi.
- Author
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Şener, Seher, Dalarslan, Sermin, and Batu, Ezgi Deniz
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ADRENOCORTICAL hormones , *CONFIDENCE intervals , *BEHCET'S disease , *MULTIVARIATE analysis , *ACUTE phase proteins , *TREATMENT effectiveness , *VENOUS thrombosis , *IMMUNOSUPPRESSIVE agents , *PREDICTION models , *COLCHICINE , *ODDS ratio , *CHILDREN - Abstract
Introduction: In our study, we evaluated the demographic and clinical characteristics of patients with pediatric Behçet's disease (BD) and our treatment approaches in these patients. In addition, we aimed to determine the predictive factors in patients who need additional immunosuppressive therapy in addition to colchicine and short-term corticosteroid therapy in the treatment of BD. Materials and Methods: Pediatric patients followed up with BD between 2004- 2022 were included in the study. The patients were divided into two groups: those receiving colchicine and/or short-term corticosteroids (group A) and those needing additional immunosuppressive treatments (group B). Results: Of a total of 103 patients, 57 (55.3%) were being followed up with a diagnosis of BD, and 46 (44.7%) with a diagnosis of incomplete BD. The most preferred drug in the treatment was colchicine (92.2%). Corticosteroids (55.3%) were often preferred with additional immunosuppressive agents in patients with major organ involvement. Biologic agents were used in 15 (14.6%) patients who were resistant to other immunosuppressive treatments. There were 56 patients in group A and 47 patients in group B. Ocular involvement and venous thrombosis were more common in group B. In addition, acute phase reactants and BHAAF scores at the diagnosis were higher in group B than in group A patients. As a result of multivariate analysis, ocular involvement [odds ratio (OR) 4,045, 95% CI 6,205-525,470; p=0.001], venous thrombosis (OR 2,497, 95% CI 3.048-48.358; p=0.001) and elevated acute phase reactants (OR 1.312, 95% CI 0.086-0.842; p=0.024) were identified as independent factors predicting the need for additional immunosuppressive therapy. Conclusion: Correct management of pediatric BD cases is very important in order to prevent complications that may develop. Our results showed that patients with ocular or vascular involvement, high acute phase reactants, and BHAAF scores may need additional immunosuppressive therapy at admission. Determining the factors that predict the need for treatment is important in making the appropriate treatment and follow-up plan for patients. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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6. Derin öğrenme temelli hibrid altın endeksi (XAU/USD) yön tahmin modeli.
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Kantar, Onur and Kilimci, Zeynep Hilal
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SOCIAL media , *SENTIMENT analysis , *DEEP learning , *INVESTORS , *PREDICTION models , *EARNINGS forecasting - Abstract
Forecasting the direction of the gold index, which determines the dollar value of 1 ounce of gold, is an attractive research topic for investors, researchers and analysts. In this study, it is aimed to construct a model that predicts the direction of the gold index based on deep learning. The proposed model is obtained as a result of blending the numerical dataset of the gold index with the textual data. This is a hybrid prediction model both in this aspect and in terms of hybrid deep learning methods used in direction prediction. As far as we know, this is the first attempt in the literature that uses the social media platform as a source for financial sentiment analysis and constructs a deep learning-based direction prediction model for the gold index by blending it with numerical data. The contribution of the study to the literature is summarized in four stages: In the first stage, in order to carry out the sentiment analysis, the dataset is cleaned and ready for modeling by methods such as parsing the dataset collected from the Twitter environment, finding the correct forms of the words in the dictionary, finding the roots of the words, normalizing the words, and cleaning the unused characters. Afterwards, the dataset is classified using 14 different deep learning-based methods. Secondly, the results of the sentiment analysis are blended with the numerical data of XAU/USD. Third, the XAU/USD direction prediction model is constructed with deep learning models. Fourth, the performance of the results from five different forecasting models in predicting the direction of XAU/USD is presented. As a result, the performance of the proposed model is significantly superior with high accuracy when compared to the state-of-the-art studies. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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7. Çok katmanlı algılayıcı ağı, uzun-kısa süreli bellek ağı ve regresyon yöntemleri ile tarımsal kurutma tahmini.
- Author
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KACAR, İlyas and KORKMAZ, Cem
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MACHINE learning , *MANUFACTURING processes , *ORGANIC fertilizers , *PREDICTION models , *PRODUCT quality , *MICROWAVE drying - Abstract
One of the processes used in the production of fertilizers, which has become an important part of agriculture, is the drying process. Determination of proper drying parameters is important both in terms of product quality and production efficiency. Regression methods are used to determine the drying process parameters frequently. In this study, in addition to the regression method, machine learning techniques are also examined such as artificial neural network, long short-term memory method. The data obtained from the drying process of a commercial organomineral fertilizer consisting of a mixture of 5% nitrogen and 10% phosphorus at 70˚C, 75˚C, and 80˚C were used for modelling. The simulation results obtained from the models of the methods and the data obtained from the experiments were compared. The predictions and performances of each model were presented. Determination the appropriate drying parameters is It is important for the drying efficiency of the product. In addition, model selection plays an important role in obtaining successful results in drying simulations. As a result, it has been observed that the prediction performance of the model created with the artificial neural network is more successful than the others. While regressions are efficient in modelling existing data, they are not successful in predicting. Moreover, it is not enough to predict the peak and pits in the drying data. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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8. TÜRKİYE KAYRAKTEPE SEDİMENT BYPASS TÜNELİNDE AŞINMA TAHMİNİ.
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YEŞİL ÖZDEN, Ayşe
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SEDIMENT transport ,BED load ,MECHANICAL abrasion ,PREDICTION models ,TUNNELS ,SEDIMENTS - Abstract
Copyright of DSI Technical Bulletin / DSİ Teknik Bülteni is the property of DSI Technical Bulletin / DSI Teknik Bulteni and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2022
9. DÖVİZ KURU VOLATİLİTESİNİ ÖNGÖRMEDE MELEZ BİR MODEL: YAPAY SİNİR AĞI TABANLI EGARCH .
- Author
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SAĞLAM BEZGİN, Müge and KAYA, Ebru
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ARTIFICIAL neural networks ,GARCH model ,TURKISH lira ,U.S. dollar ,PREDICTION models ,FOREIGN exchange rates - Abstract
Copyright of Journal of Financial Politic & Economic Reviews / Finans Politik & Ekonomik Yorumlar is the property of Journal of Financial Politic & Economic Reviews / Finans Politik & Ekomomik Yorumlar and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2022
10. Teknolojik değişimlerin patent verilerine dayalı istatistiksel kontrol grafikleri ile izlenmesi.
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Mutlu, Nazlı Gülüm and Altuntaş, Serkan
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INDUSTRIAL safety , *PATENT offices , *TIME series analysis , *MEDICAL technology , *PREDICTION models , *QUALITY control charts , *TECHNOLOGICAL forecasting - Abstract
Technology forecasting constitutes the basis of technology development and investment in technology. In a dynamic environment where technology is rapidly evolving and growing, the need to check the availability of a single prediction model has become an important research topic. The aim of this study is to follow the development of safety technologies in the field of occupational health and safety by using statistical quality control charts. Expanding the I-MR control chart rules used in monitoring the reliability of the technology forecasting model and considering the safety technologies in the field of occupational health and safety (OHS), which were previously discussed in the literature, are the original aspects of the study. At the beginning of the study, 91,580 patent data, was anlaysed using the United States Patent and Trademark Office (USPTO) database during including 1942-2020 (December) period. Time series modeling is performed using patent data on safety technologies, and I-MR graph is created using residual values of the model. The reliability of the model is monitored by controlling significant deviations with the obtained I-MR graphics. In addition, an S-curve is created for the patent numbers. The results of this study show that using a single technology forecasting model for a long period of time is misleading. Additionally, the forecast model for the period between 1942 and 2020 should be updated in various periods. Occupational health and safety technologies are an emerging technology field and appear to be incentives for policy makers and safety engineers to allocate resources. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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11. Kalça Protezi Ameliyatlarına Yönelik Bir Öneri: Olasılığa Dayalı Sürveyans.
- Author
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Hekimoğlu, Can Hüseyin, Batır, Esen, Gözel, Emine Yıldırım, and Meşe, Emine Alp
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PUBLIC health surveillance , *TOTAL hip replacement , *CONFIDENCE intervals , *AGE distribution , *RISK assessment , *HUMAN services programs , *SEX distribution , *SURGICAL site infections , *DESCRIPTIVE statistics , *PUBLIC hospitals , *PREDICTION models , *LOGISTIC regression analysis , *RECEIVER operating characteristic curves , *ODDS ratio , *DISEASE risk factors ,SURGICAL complication risk factors - Abstract
Objective: Surgical site infection (SSI) surveillance is time-consuming and hard. Identifying high-risk patients and focusing on these patients will be cost and time effective. This study aims to develop a model to identify high-risk patients for the development of SSI after hip replacement surgery and to estimate the utility of the model. Methods: Logistic regression model was created to determine the risk of SSI development using the National Health Service Associated Surveillance Network (USHİİSA) data. The stability of the model was tested using the Bootstrap resampling method. The individual probability of developing SSI was determined for each patient by using the model. The threshold probability to be used in distinguishing high-risk patients was found 1.2% by ROC analysis. For hospitals with different SSI rates and surveillance sensitivity, the utility of the model has been estimated by various parameters. Results: Female gender (OR:1.52; 95% CI:1.22-1.88), being over 65 years of age (OR:2.06; 95% CI:1.63-2.62), procedure duration longer than 75th percentile (OR:1.32; 95% CI:1.07-1.63), ASA score over 3 (OR:2.10; 95% CI:1.48-2.99), and surgery performed in a hospital other than a private hospital (p<0.001) were found to be independent risk factors for the development of SSI. When focusing on high-risk patients, as the rate of SSI of a hospital increases, the number of patients that need to be focused on detecting one more SSI decreased, and the number of additional SSIs increased. As the surveillance sensitivity of the hospitals decreases, the new rate obtained differs more from the old rate. Conclusions: Focusing on high-risk patients identified using the model caused to eliminate approximately half of the patients, thus saving labor and time. Using this model can be particularly beneficial for hospitals with a high SSI burden and low surveillance capacity. The model can be integrated into the national surveillance system so that highrisk patients can be prioritized. Modeling may be considered for the other surgeries. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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12. Kardiyak Cerrahide Mortalite Tayini: Kalp Cerrahi Skorlaması (CASUS) Sistemi Etkin mi?
- Author
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Polat, Senem and Yurtseven, Nurgül
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INTENSIVE care units , *CARDIAC surgery , *RECEIVER operating characteristic curves , *PREDICTION models , *MORTALITY - Abstract
Objective: This study was planned to evaluate effectiveness of cardiac surgery score (CASUS) system used for the prediction of mortality after the cardiac surgery and to compare it with EuroSCORE, a tested and approved method. Method: Fifty patients over the age of 18 who came to the intensive care unit (ICU) after open heart surgery and stayed in the ICU for more than 48 hours were prospectively included in the study. After the preoperative EuroSCORE evaluation of the patients, CASUS scoring systems were used for risk scoring from postoperative 0 day to the service or up to the 6th postoperative day (or possible mortality) in patients whose stay in ICU was prolonged. We evaluated the place of both models in the prediction of ICU mortality. Results: The study was conducted with 50 patients- 21 female, 29 male-, aged between 19 and 79 years (mean age: 60.38±12.50). Five (10%) cases exited.The areas under the ROC curve were estimated as follows: EuroSCORE, 45.3%; and for CASUS 0,1, and 2. day scores AUCs of ROC curve were 66,9%, 64,7%, and 79,8%, respectively. The CASUS 2nd day score was found to be valuable in predicting mortality (p<0.01). A statistically significant relationship was observed between the days of stay in the ICU and mortality. Conclusion: Our results show that the rate of the accurate prediction of mortality of CASUS is insufficient on postop 0th and 1st day; however CASUS score on postoperative 2nd day has sufficient.predictive accuracy EuroSCORE is not found effective in the prediction of mortality. It is observed that if the duration of stay in ICU is prolonged, it statistically significantly increases the risk of mortality. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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13. GRİ TAHMİNLEME İLE SÜLEYMAN DEMİREL ÜNİVERSİTESİ AĞIZ DİŞ SAĞLIĞI MERKEZİ'NDE YATAN HASTA SAYILARININ TAHMİNİ.
- Author
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ORUÇ, Kenan Oğuzhan and BAŞAĞAOĞLU FINDIK, Ayşe
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SCIENTIFIC method , *TIME series analysis , *ERROR rates , *UNIVERSITY faculty , *PREDICTION models - Abstract
In today's world, there is a steady increase in demand for healthcare. It is very important to realize these services that involve human health without interruption. For this reason, it is very important planning future steps for health services. Estimates made by scientific methods will greatly assist the planning of these units. This study; tries to determine the number of Inpatient Forecast with Grey Forecasting for Süleyman Demirel University Faculty of Dentistry. For the study, the data of 56 months is collected from the inpatient service between January 2015 and August 2019 is used during the process of estimation. In this study, estimations are made for 28 months covering the period of September 2019 to December 2021. Multiplication separation method is used in the process of separating the data with the time series feature from the seasonal effect. The accuracy (p) and error rate (C) criteria which are frequently used in MAPE and Gray Estimation are used to determine the predictive success of the model. According to the results of these evaluations made, P value is 0.82, C value is 0.46 and MAPE value is % 21. As a result of these values, a successful result was obtained from the study. [ABSTRACT FROM AUTHOR]
- Published
- 2020
14. Gri Tahmin Modelleri ile Toplam Enerji Talep Tahmini: Türkiye Örneği.
- Author
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ES, Hüseyin Avni
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FORECASTING , *PREDICTION models , *TIME series analysis , *ENERGY consumption , *ENERGY policy , *DEMAND forecasting - Abstract
Energy demand forecasts are needed for developing and emerging countries to be able to determine sustainable energy policies. Grey prediction models can make successful predictions with limited data without the need for any prior information. In this study, Grey prediction models are considered for the total energy demand of Turkey that shows significant economic and social development in recent years. Grey prediction includes forecasting models based on time series and cause-effect relationships. Four different grey prediction models including GM (1,1) and Grey Verhulst from the time series models, and GM (0,N) and GM (1,N) based on the cause-effect relationships were discussed. The purpose of using two types of forecasting structures is to achieve reliable and strong forecasts by capturing the recent trend with the time series and obtaining the change in energy demand by cause-effect relationship. GM (1,1) and Grey Verhulst model has been established with past total energy consumption data. By using independent variables of GDP, population, import, export and building surface area for GM (0, N) and GM (1, N) models, GM (0,6) and GM (1,6)models were formed. All applied models have been compared according to performance criteria, GM (1,1) and GM (1,6) have been designated to be superior models that performed successful predictions. As a result; Turkey’s total energy demand has been forecasted up to 2025 with GM (1,1) based on time series and GM (1,6) including high and low scenarios. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
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15. Sensör ve Akıllı Telefon Kayıtları Yardımı ile Yapının Dinamik Karakteristiklerin Belirlenmesi.
- Author
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UYAR, Hidayet and AĞCAKOCA, Elif
- Subjects
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INTELLIGENT sensors , *SMARTPHONES , *SIDING (Building materials) , *PREDICTION models , *STEEL - Abstract
In this study, the vibration ratios obtained from the sensor and smartphone placed in the steel model structure in the vibration table and the vibration ratios generated using the MATLAB mathematical prediction model were compared. The steel model structure used in the experimental study; made of single-span, four-ply steel. Column-beam connections in the steel model structure are rigid and the base connections on all four sides of the model building are mounted to the vibration table. The vibration values obtained from the experimental study were obtained from the sensor and the smartphone placed at the base of the vibration table and at the top of the steel model structure. The vibration table was forced with the vibration values of El-Centro, Loma-Prieta, Kobe and Sakarya earthquakes and the vibrations caused by the strain caused by the structure were recorded with the help of sensor and smart phone. Sensor and smartphone vibration values at the base of the shaking table are defined as input, sensor and smartphone vibration values at the top of the steel model structure are defined as output to the system. As a result of the studies, the compatibility ratios between the input-output data obtained experimentally, the autoregressive ARX in the Matlab program and the autoregressive moving averages were compared between the prediction-prediction found in the ARMAX model and the input-output produced. In addition, the difference between sensor and smartphone acceleration data was investigated and which of the methods used gave better results. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
16. Trakya Bölgesi'nde İklim Değişikliğinin Buğday Verimine Etkisinin AquaCrop ve WOFOST Modeller ile Tahmin Edilmesi.
- Author
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KONUKCU, Fatih, DEVECİ, Huzur, and ALTÜRK, Bahadır
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AGRICULTURAL productivity , *CLIMATE change , *ATMOSPHERIC models , *PREDICTION models , *WHEAT - Abstract
Since climate change will adversely affect the agricultural sector as well as many other sectors, the effects of climate change on agricultural production should be estimated and necessary measures should be taken. The aim of this study is to determine the effect of climate change on wheat yield in the short (2020-2030), medium (2046- 2055) and long (2076-2085) term periods in the Thrace Region using AquaCrop and WOFOST models. RegCM3 Regional Climate Model, reference and A2 scenario outputs were used to predict climate change. In the 1970- 1990 period, the measured temperature and precipitation data measured in the research area were compared with the model reference data and changes were estimated in the short, medium and long term periods. Wheat yields obtained from farmer fields in three different locations (Akıncılar, Sofular, Çövenli) in Çorlu Pınarbaşı sub-basin in 2016-2017 growing period were compared with the model prediction in order to do the calibration and yields were forecasted in the future periods. As a result, in the short term, an average 0.27 °C decrease in temperature were forecasted whereas 1,43 °C and 3,05 °C increase were estimated for medium and long terms, respectively when compared to model reference years. In total rainfall, 87 mm (13%) increase, 91 mm (14%) and 78 mm (12%) decreases were simulated for the short, medium and long-terms. AquaCrop Model predicted yield increases up to 50% in Akıncılar and Çövenli and yield decreases of 6% - 34% in Sofular whereas WOFOST Model predicted increases of 40% in Akıncılar and 12% in Sofular and decrease up to 2 - 7% in Çövenli. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
17. Türkiye'de Trafik Kazalarında Meydana Gelen Ölü Sayısı Tahmin Modellerinin Geliştirilmesinde Logaritmik Regresyon ve Yapay Sinir Ağları Metotlarının Kullanılması.
- Author
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Cansız, Ömer Faruk
- Subjects
ARTIFICIAL neural networks ,TRAFFIC accidents ,INDEPENDENT variables ,DEPENDENT variables ,PREDICTION models - Abstract
Copyright of Karaelmas Science & Engineering Journal / Karaelmas Fen ve Mühendislik Dergisi is the property of Karaelmas Science & Engineering Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2018
- Full Text
- View/download PDF
18. Örnek tabanlı sınıflandırıcı topluluklarıyla yeni bir klinik karar destek sistemi.
- Author
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Bulut, Faruk
- Subjects
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OBESITY risk factors , *MACHINE learning , *CLINICAL medicine software , *CLASSIFICATION , *PREDICTION models - Abstract
The main reason of obesity occurring in the future years is strongly related with the lifestyle and eating habits in childhood. This study focuses on developing an urgent precaution system which calculates the obesity risks. An original clinical decision support system (CDSS) has been developed by using Ensemble Classification methods in Machine Learnings. A questionnaire has been prepared and applied to the patients in the hospitals and to the elementary school students with official permissions in order to construct an original and reliable dataset. Extended versions of k Nearest Neighbors methods are used in Voting, Bagging, Boosting and Random Subspaces algorithms as base learners. During the experimental studies in the applications of cross validation procedures, successful results have been computed and Random Subspaces has been chosen as the most successful algorithm with 0.839 MCC (Matthews Correlation Coefficient) scores. With the help of the suggested model to a worldly wide health problem, the future probability of obesity risk for a child might be easily determined. Additionally, it has been enabled that some precautions can be taken by responsible people if there is a computed high risk for this child. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
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19. YÜK TAŞIMACILIĞININ ŞEHİR İÇİ KARAYOLU HACMİNE ETKİLERİNİN KESTİRİMİ: İZMİR ÖRNEĞİ.
- Author
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ORAL, Yıldırım and GÜLHAN, Görkem
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ROADS , *CITIES & towns , *PREDICTION models , *URBAN transportation , *URBAN planning - Abstract
Planning paradigms, which aim to overcome urban transport problems, have to evaluate the mobility prediction of goods besides the mobility of individuals. This is a requirement and it comes up with different scales and features in the cities which contain high density of regional interactions. Urban roads respond from freight transport due to economy besides relation of productions and consumptions. This study is an instance to generate solutions for future which tries to evaluate respective interaction in the process of urban planning and transport planning. Study area has been stated as the city Izmir, TURKEY. The exact area is the legal responsibility border of the law 3030. The location and impact of freight transport generation stations cause total freight transport demands to rise up. Concurrently, there is a high ratio of freight transport in the transit traffic. Freight vehicles may be seen in every level of roads due to features of the road network. Therefore, it has been aimed to correlate freight transport moves with the location and impacts of the freight generation stations. This study also assumes that freight transport moves may have some measurable reasons and may contain usable parameters, for this purpose. The measurement of freight transport in Izmir, the density of the vehicles which interacts with the several aggregation areas and the location or impacts of the freight transport generation stations in those areas have been tried to evaluate simultaneously. The stages of the paradigm are determined as below: • To determine the categories of the freight transport generation stations and measurement values on urban roads, • To draw the borders of several aggregations areas and CBD area borders by determining enumeration points, • To measure density of freight vehicles move in terms of inner traffic. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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20. BANKALARIN FİNANSAL BAŞARISIZLIKLARININ DİSKRİMİNANT ANALİZİ VE YAPAY SİNİR AĞLARI ÇERÇEVİSİNDE TAHMİNİ.
- Author
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ALTUNÖZ, Utku
- Subjects
BANK failures ,ARTIFICIAL neural networks ,PREDICTION models ,DISCRIMINANT analysis ,BANKING industry - Abstract
Copyright of Sakarya Journal of Economics / Sakarya Iktisat Dergisi is the property of Sakarya Journal of Economics / Sakarya Iktisat Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2013
21. Koroner arter baypa s greftleme sonrası erken mortalitenin belirlenmesinde standart, lojistik Euroscore ve Euroscore Il'nin karşılaştırılması.
- Author
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Akgül, Ahmet, Gürsoy, Mete, Bakuy, Vedat, Polat, Ebru Bal, Kömiircii, Ibrahim Giirkan, Kavala, Ali Ayçan, Türkyilmaz, Saygin, Çaglar, Ilker Murat, Tekdös, Yasemin, Atay, Mehmet, Altini, Senel, Gulmaliyev, Cabir, and Memmedov, Seymur
- Subjects
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CORONARY artery bypass , *MORTALITY , *LOGISTIC model (Demography) , *RISK assessment , *PREDICTION models , *MEDICAL statistics - Abstract
Objective: EuroSCORE is the most widely used risk prediction system. Standard EuroSCORE which had been published in 1999, was revised as a Logistic EuroSCORE in 2003. Further it was reconsidered and published as EuroSCORE II in 2011. In this study we compared Standard, Logistic EuroSCORE and EuroSCORE II in prediction of early mortality following coronary artery bypass grafting. Methods: We retrospectively analyzed 406 patients who underwent coronary artery bypass grafting operation between 2011-1012. Standard, Logistic and new version were compared with ROC analysis. Results: In general population, mean standard EuroSCORE was 3.25±1.05, mean logistic EuroSCORE was found 2.48±0.58, mean EuroSCORE II was found 1.30 ± 0.09 and overall mortality was 10 (10/406 2.46%). Area under curve (AUC) was found 0.992 95% CI: 0.978-0.998 for standard EuroSCORE, 0.992 95% CI: 0.977-0.998 for logistic EuroSCORE and 0.990 95% CI: 0.975-0.997 for EuroSCORE II. In high risk patients (patients with standard EuroSCORE > 6) AUC was found 0.870 95% CI 0.707-0.961 for standard EuroSCORE, 0.857 95% CI 0.691-0.954 for logistic EuroSCORE, and 0.961 95% CI: 0.829-0.998 for EuroSCORE II. Conclusion: Standard, Logisti c EuroSCORE and EuroSCORE II are similarly successful in mortality prediction. EuroSCORE II may be better in high-risk patients which needs confirmation in large prospective studies. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
22. Okul Yöneticilerinin Özyeterlik Algıları ile Çatışmayı Çözme Stratejileri Arasındaki İlişki.
- Author
-
İnandı, Yusuf, Tunç, Binali, and Gündüz, Bülent
- Subjects
SCHOOL administrators ,SELF-efficacy in students ,CONFLICT management ,EDUCATIONAL planning ,EDUCATIONAL surveys ,EDUCATIONAL quality ,PREDICTION models ,EDUCATION research - Abstract
Copyright of Educational Administration: Theory & Practice is the property of Educational Administration: Theory & Practice and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2013
23. BİLMENİN İLLÜZYONU: MATEMATİKSEL PROBLEM ÇÖZME VE TEST KALİBRASYONU.
- Author
-
ÖZSOY, Gökhan and KURUYER, Hayriye Gül
- Subjects
- *
PROBLEM solving , *CALIBRATION , *METACOGNITION , *PREDICTION models , *FIFTH grade (Education) , *STUDENTS - Abstract
Prediction and evaluation which are metacognitive skills called calibration. Test calibration is a measure of difference of current test score and predicted score. With this respect, the purpose of this study is to investigate primary school fifth grade students' problem solving achievement and their test calibration, and the relationship between problem solving skills and calibration skills including prediction and evaluation. One hundered twenty five students enrolling to fifth grade are participated in the study. Students' problem solving skills and their test calibration status were measured by administering the Problem Solving Achievement Test (PC AT) which is developed by the authors. The results of the study revealed that there is no significant releationship between problem solving achievement and test calibration (r = 0.091,p > .05); additionally results also showed that there is a significant negative relationship (r = - 0.816, p < .01) between problem solving achievement and confirmed test calibration. [ABSTRACT FROM AUTHOR]
- Published
- 2012
24. ÖZEL DERSHANELERDE GÖREV YAPAN ÖĞRETMENLERİN ÖRGÜTSEL ADALET ALGILARI.
- Author
-
YAVUZ, Mustafa
- Subjects
ORGANIZATIONAL justice ,PRIVATE schools ,SOCIAL security ,JOB security ,TEACHERS ,PREDICTION models - Abstract
Copyright of Electronic Turkish Studies is the property of Electronic Turkish Studies and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2012
25. YALIN SİNİRSEL BULANIK BİR MODEL İLE İMKB 100 ENDEKSİ TAHMİNİ.
- Author
-
OK, Yeşim, ATAK, Mehmet, and AKÇAYOL, M. Ali
- Subjects
- *
STOCK exchanges , *FUZZY systems , *PREDICTION models , *MATHEMATICAL models of forecasting , *MATHEMATICAL variables , *MATHEMATICAL models - Abstract
In this paper, Istanbul Stock Exchange (ISE) National 100 Index retrospective predictability was tested by using the Adaptive Neuro Fuzzy Inference System (ANFIS). In addition, contribution of the inputs to the model for index forecasting was evaluated on the basis of prediction performance. The most important factor to successful stock market prediction is achieving best results using minimum required input data and the least complex stock market model. In this context, we aim to prove consistent prediction of ISE 100 index without having to use a lot of input variables with ANFIS. For this purpose, about four and a half year period was chosen as the analysis period; two input variables (the exchange rate and repurchasing interest rate) and three input variables (the exchange rate, repurchasing interest rate and trading volume) were established in two different models. Consistent prediction results have been obtained with high predictive factor with both of the models. As a result, that is concluded that the ISE 100 Index has short-term predictability using only two input variables, without the need for a complex model with ANFIS. [ABSTRACT FROM AUTHOR]
- Published
- 2011
26. LİSE SON SINIF ÖĞRENCİLERİNİN DEPRESYON DÜZEYLERİNİ YORDAYAN SOSYO-DEMOGRAFİK DEĞİŞKENLERİN BELİRLENMESİ.
- Author
-
EMİROĞLU, Mürşide, MURAT, Mehmet, and BİNDAK, Recep
- Subjects
- *
PSYCHOLOGY of high school students , *MENTAL depression , *SOCIODEMOGRAPHIC factors , *PREDICTION models , *QUESTIONNAIRES , *SOCIOECONOMIC factors , *HEALTH behavior , *PSYCHIATRY - Abstract
This study was conducted to determine the socio-demographic factors affecting 12th grade students' depression levels. The sample of the research consists of 146 (46%female, 54% male), 12thgrade students from ismetpas.a high school in şehit Kamil, Gaziantep. The data were obtained from 146 students and were collected through "Beck Depression Inventory" and a questionnaire. The data were analyzed by stepwise linear regression analysis. The results of the study showed that the significant predictors of students' depression levels were the socio-economic level according to their perception, sleep problems, perception of their health status, number of brothers/sisters and students' gender. There is need for more research to determine psychological and psychiatric problems among high school students. [ABSTRACT FROM AUTHOR]
- Published
- 2011
27. Omurilik Yaralanmasında Otonomik Disrefleksi.
- Author
-
Köseoğlu, Ebru and Karataş, Gülçin Kaymak
- Subjects
SPINAL cord injuries ,CEREBROVASCULAR disease diagnosis ,DYSAUTONOMIA ,PREDICTION models ,PHARMACOLOGY ,ETIOLOGY of diseases ,PATHOLOGICAL physiology - Abstract
Copyright of Journal of Physical Medicine & Rehabilitation Sciences is the property of Turkiye Klinikleri and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2011
28. Şiddet İçeren Suç Davranışı Öngörülebilir mi? Erkek Mahkumlarda Yürütülen Bir Cezaevi Çalışması.
- Author
-
Güleç, Hüseyin, Güleç, Medine Yazıcı, Kaymak, Semra Ulusoy, Topaloğlu, Mürüvvet, and Ak, İsmail
- Subjects
- *
VIOLENCE , *CRIME , *PREDICTION models , *PRISON system , *MALE offenders , *SOCIAL problems , *SOCIODEMOGRAPHIC factors - Abstract
Objectives: Violence is an important social problem, which frequently coexist with offense. In this study, sociodemografic, historical and clinical features of the male offenders, and the relationship of these features with violent behaviour and feelings of compunction has been investigated. Method: One hundred and sixteen male offenders were enrolled in the study. Subjects were separated into two groups as violente offenders (42) non-violente offenders (74). Participants' history, sociodemographic data and clinical futures are assessed with a semi-structured interview. Previous violence, age of first violent behavior, relationship instability, employment problems, substance use, self destruction and compunction were asked. Temperemant and Character Inventory, Self Directedness Subscale, general symptom level, Plutchik and van Praag's impulsivity test were applied. Results: Employment problems and young age at first violent incident were more common in violent offenders. In addition, although major mental illnesses in this group were higher, it didn't show statistical significance. Major mental illness in the history and employment problems were predicted violent behavior. None of the variables was predicted compunction. Conclusion: The history of the employment problems, the young age at first violent and the psychiatric disorders are seen to be the risk factor for the violent behavior in the offenders. To create data about the understanding of our population provides a right basic which is necessary for community and psychiatric rehabilitation interventions dealing with prevention of violent and offense. [ABSTRACT FROM AUTHOR]
- Published
- 2011
29. İstanbul ofis kira tahmin modeli geliştirilmesi.
- Author
-
Pekdemir, Dilek and Dökmeci, Vedia
- Subjects
- *
OFFICE building leasing & renting , *PREDICTION models , *REGRESSION analysis , *MULTICOLLINEARITY - Abstract
In the last quarter of previous century, economic, social and technological development caused a change in employment structure and an increase in the share of service sector. Demand for modern office space was driven by faster growth in finance, insurance, real estate (FIRE) subsectors. Existing office inventory could not meet modern space requirement, hence new metropolitan areas has started to develop. Office demand has an important role in metropolitan urban development and emergence of new subcentres. Therefore, office rent prediction is a crucial issue in decision making of new office investments and planning strategies. Office rent prediction models have been the major concern of academic research since 1980s. Hedonic office rent prediction models which are the most common method based on multiple regression are well established in the literature. A wide range of variables, categorised as econometric, architectural, spatial and tenure rights, are used in these models for various cities. It is difficult to incorporate large number of variables into a simple mathematical model. As a result, the need has arisen to reduce or group the excessive number of variables to achieve simplier mathematical expressions with greater explanatory power. In the light of previous studies, some difficulties can arise in gathering data and applying the hedonic theory. The major difficulty lies within the hedonic regression models is the multicollinearity problem that may exist between a large number of independent variables. The common solution is exclusion of some variables depending on significance level or using "stepwise" or "backward" procedure in regression models. Another problem with development of rent prediction model is selection of dependent variable. In the literature, asking rent is preferred in some models while contract rent or effective rent are used in others, as the dependent variable. It is reported that the use of contract or effective rent instead of asking rent, can provide more accurate predictions. However, it is difficult to obtain sufficient contract data from real estate firms, due to confidentiality and competition. The aim of this study is to examine the problem with construction of an office rent prediction model and development of a viable prediction model for Istanbul. For this purpose, a proposed regression model is constructed with using asking rent, gross and net contract rents, as dependent variable for 1996 2006 period. First, full model is developed with thirtyfour variables, then a reduced model is constructed by eliminating some variables using "backward" procedure in standard regression model. Finally, the performances of prediction models are compared according to Rsquared and tstatistics. In addition, Akaike Information Criteria and Schwarz Bayesian Criteria are also employed to test the accuracy of proposed models. Based on the findings of most accurate model, the significant variables are defined for Istanbul office market. The similarities and differences from literature findings are discussed. The results confirmed that use of contract rents instead of asking rents can provide robust predictions with higher explanatory power. Besides, the reduce models offer better solution for multicollinearity problem. Building and locational variables are found the most significant office rent determinants for Istanbul metropolitan areas. The findings point out importance of accessibility and locational prestige in site selection for new office investments. Especially, distance from the CBD and important transportation nodes (Bosphorus Bridge, highway connection) have an important role to explain in rental change, in line with global literature. Results reveal that secondary centres gain importance. This strengthens the assertion that the tendency for office investment in Istanbul is away from the traditional centre (CBD) and closer to secondary centres. However, rental values are still higher in the CBD. For further studies, it is aimed to increase number of data to obtain more accurate prediction model for Istanbul. It is expected that office rent prediction models will be helpful to determine new office areas. [ABSTRACT FROM AUTHOR]
- Published
- 2011
30. Fallot tetralojili on iki ay altı infantlar ile bir-dört yaş arası çocuk hasta gruplarında tam düzeltme ameliyatı sonrasında kısa dönem mortalite ve morbiditenin belirleyicileri.
- Author
-
Şaşmazel, Ahmet, Fedakar, Ali, Baysal, Ayşe, Çalışkan, Ahmet, Buğra, Onursal, and Sunar, Hasan
- Subjects
- *
TETRALOGY of Fallot , *CONGENITAL heart disease , *CHILD mortality , *QUANTITATIVE research , *PREDICTION models ,MORTALITY risk factors - Abstract
Objective: In patients with tetralogy of Fallot, infants less than 12 months old and children between one and four years old were compared after total repair surgery for determination of outcome of surgery, risk factors influencing mortality and morbidity. Methods: Fifty- two patients with tetralogy of Fallot between five months and four years of ages were included into the study. The patients were divided into two groups depending on their ages; Group 1; one year old and younger (n=21) whereas, group 2; one and four years old (n=31). Statistical analysis was performed using Mann-Whitney U, Chi-square or where appropriate Fisher's exact tests and logistic regression analysis was applied for determination of predictors of mortality. Results: The parameters that were different between two groups include; age (Group 1; 10.00±1.67 months and Group 2; 2.39±0.77 years, p<0.001), weight (Group 1; 9.74±2.23 kg, Group 2; 11.97±1.78 kg, p<0.001), McGoon ratio (Group 1; 1.94±0.29, Group 2; 2.19±0.27, p=0.001). Mortality is found in 3 patients in group 1 (14.2%) whereas, in five patients in group 2 (16%) and the difference was not statistically significant. In group 2 in only one patient (0.03%) had complete atrioventricular block and required permanent pacemaker implantation. When patients were compared according to groups with and without mortality, the significant differences were found in following variables: peritoneal dialysis (p=0.001), pleural effusion (p=0.02), right ventricular pressure (p=0.001) and right ventricle/aorta pressures ratio (p=0.001). However, none of these risk factors had significant value in prediction of mortality. Conclusion: Depending on these results, in patients under one year of age with symptomatic tetralogy of Fallot, if there are no other pathologies that have potential to increase risk of mortality, the complete repair surgery can be performed with same amount of risks and similar morbidity and mortality ratios. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
31. BELİRGİN DALGA YÜKSEKLİKLERİNİN NEURO-FUZZY YAKLAŞIMI İLE TAHMİNİ: FİLYOS DENİZ YÖRESİ ÖRNEĞİ.
- Author
-
TÜR, Rıfat and BALAS, Can Elmar
- Subjects
- *
COASTAL engineering , *WAVES (Physics) , *PREDICTION models , *ARTIFICIAL neural networks - Abstract
First and the most important phase of designing high cost coastal structures is to forecast the significant wave height (Hs). In this study, an alternative approach to the deterministic and stochastic methods found in literature is proposed. Neuro-fuzzy is a method in which advantages of Artificial Neural Networks (ANN) and Fuzzy Logic (FL) are combined. In the Neuro-Fuzzy models developed in this study, daily significant wave height can be estimated using daily average Hs and significant wave period (Ts) data. Hs and Ts data recorded at different time intervals were used in the proposed models. In this study, Hs and Ts measured in Filyos region of the Black Sea was estimated by the Adaptive Network-based Fuzzy Inference System (ANFIS). Predicted results from proposed models were compared with the measured wave data and it is found that high correlation values are obtained. It is thus concluded that the proposed models can efficiently be used to estimate missing wave data. [ABSTRACT FROM AUTHOR]
- Published
- 2010
32. BULANIK MANTIK VE İSTATİSTİKSEL ANALİZ YÖNTEMLERİ İLE REVİBRASYON UYGULANMIŞ BETONLARDA BASINÇ DAYANIMI TAHMİNİ.
- Author
-
Subaşi, Serkan, Beycıoğlu, Ahmet, and Çullu, Mustafa
- Subjects
- *
CONCRETE testing , *MATERIALS compression testing , *PREDICTION models , *FUZZY logic , *REGRESSION analysis , *VIBRATION measurements - Abstract
The purpose of this study is to develop two different prediction models based on regression analysis and fuzzy logic for prediction of compressive strength of concrete samples which were subjected to vibration for different amount of time. For this study, a total of 50 cubic samples in C 16 class were prepared. The sample sizes were 15x15x15 cm. After applying 10 second initial vibration to all samples, they were grouped in to tens. Later, 30, 60, 90 and 120 second vibrations were applied to four different groups of samples. The samples in the last group were left un-vibrated. On the 28th days, unit weights and compressive strengths of the samples were measured. Using these measurements, two prediction models were developed. With these newly developed regression analysis and fuzzy logic models, compressive strength values were predicted in relation to unit weight and vibration time. The results obtained from the prediction models were compared to the results obtained from the tests and prediction performances of the new models were evaluated comparatively. The results showed that compressive strength of concrete can be predicted using fuzzy logic and multiple linear regression models. Moreover, it has been observed that fuzz logic model can predict concrete compressive strength with less amount of error compared to the multiple-linear regression model. [ABSTRACT FROM AUTHOR]
- Published
- 2010
33. ŞEHİRİÇİ KONTROLSÜZ EŞDÜZEY KAVŞAK KAZALARINI ETKİLEYEN UNSURLARIN DEĞERLENDİRİLMESİ.
- Author
-
SaplioĞLU∗, Meltem and KaraŞahİn, Mustafa
- Subjects
- *
TRAFFIC safety , *ROAD interchanges & intersections , *PREDICTION models , *GEOMETRIC analysis , *URBAN transportation - Abstract
Theory and models used for effective measures against traffic accidents, are main sources. Data must be in high quality and sufficient quantity in intersection safety reseaches and it is possible with making depth research. Until now, in no uncontrolled intersection study has been examined together with all effecting factors. Therefore, when creating accident prediction model sor performing intersection safety analysis, there is always a restriction for the effecting parameters. In this study, accident affecting factors except the human factor, road and environmental factors, especially the geometric features of intersections have been examined for urban uncontrolled intersections. The study aims to remendy deficiencies related to urban uncontrolled intersection safety analysis and it is thought the results could shed light on the values of intersection safety researches. [ABSTRACT FROM AUTHOR]
- Published
- 2010
34. ARMAX Modelleri ve Porsuk Baraji Su Seviyesinin Öngörüsü.
- Author
-
Sen, Hülya and Özaydın, ve Özer
- Subjects
WATER levels ,MATHEMATICAL models ,PREDICTION models ,WATER shortages ,FLOODS ,STATISTICS ,DAMS - Published
- 2009
35. Harran Kili Şişme Özelliklerinin Değerlendirmesi ve Dolaylı Tahmini.
- Author
-
Türköz, Murat and Tosun, ve Hasan
- Subjects
CLAY ,METHYLENE blue ,MULTIPLE regression analysis ,SOIL testing ,PRESSURE ,PREDICTION models - Published
- 2009
36. SMEED VE ANDREASSEN KAZA MODELLERİNİN TÜRKİYE UYGULAMASI: FARKLI SENARYO ANALİZLERİ.
- Author
-
AKGÜNGÖR, Ali Payıdar and DOĞAN, Erdem
- Subjects
- *
TRAFFIC accidents , *PREDICTION models , *DATA analysis - Abstract
In this study, accident prediction models for Turkey were developed by using the historical data, between 1986 and 2005, including population (P), the number of vehicles (N), accidents (C), injuries (I), and fatalities (D). In the models development, the structural form of Smeed and Andreassen Models were employed. However, Smeed Model was developed in different point of view so that this model was called as Smeed Similarity Model. The number of accident, injury and fatalities in Turkey which is on the way of a full member of European Union, were tried to estimate under different three scenarios until the year of 2010. Both models were compared in terms of percent difference (PD), mean absolute percent errors (MAPE), and root mean square errors (RMSE). Despite that Andreassen model for the years between 1986 and 2005 had errors lower than Smeed Similarity model, for future estimates latter gave more plausible results with scenarios. [ABSTRACT FROM AUTHOR]
- Published
- 2008
37. UYARLAMALI SİNİRSEL BULANIK MANTIK YAKLAŞIMI İLE AYLIK SU TÜKETİMİNİN TAHMİNİ.
- Author
-
Fırat, Mahmut, Yurdusev, M. Ali, and Mermer, Mutlu
- Subjects
- *
FUZZY systems , *PREDICTION models , *WATER consumption , *FORECASTING , *DEMAND chain planning , *SOCIOECONOMIC factors - Abstract
In this study, an adaptive Neuro-Fuzzy inference system (ANFIS) is used to forecast monthly water use from several socio-economic and climatic factors, which affect water use. Totally 108 data sets are collected and data sets are divided into two subsets, training and testing. The models consisting of the combination of the independent variables are constructed and the best fit input structure is investigated. The performance of ANFIS models in training and testing sets are compared with the observations and the best fit model forecasting model is identified. For this purpose, some criteria of performance evaluation such as, Root Mean Square Error (RMSE), efficiency (E) and correlation coefficient (CORR) are calculated for all models. Then, the best fit models are also trained and tested by Multiple Regression (MR). The results of models are compared to get more reliable comparison. The results indicated that ANFIS can be applied successfully for monthly water demand forecasting [ABSTRACT FROM AUTHOR]
- Published
- 2008
38. ENFLASYONUN ARIMA MODELLERİ ARACILIĞIYLA TAHMİNLENMESİ.
- Author
-
Güner, Ümit and Subaşi, Devrim Bariş
- Subjects
- *
BOX-Jenkins forecasting , *MATHEMATICAL models of inflation , *PREDICTION models , *ECONOMIC indicators , *TIME series analysis - Abstract
Inflation is one of the most important indicators that economic agents follow closely in arranging and planning their activities. In most cases, the expected inflation rates, in other words, the inflation forecasts are as important for the economic agents as the realized inflation rates. In this study, the inflation series starting from 1998-January to 2007-March are fitted using ARIMA models. In addition to the ARIMA models, in the study, the alternate univariate time series models are applied to the inflation series. However, on the basis of performance criteria these models fall below the base model. According to these performance criteria, the SARIMA(0,1,1)(0,0,1) model is found to be as the best model. Finally this model is used to get inflation forecasts in sample and out of sample. The main forecasting implication of the model is although there will be a short term rise in inflation rates, this increase will not change the inflation's long term decrease tendency. [ABSTRACT FROM AUTHOR]
- Published
- 2007
39. Epistemolojik açıdan büyük veri ve gelecek tahmin sistemleri
- Author
-
Dalgalıdere, Sertaç, Işıklı, Şevki, Gazetecilik Anabilim Dalı, and Gazetecilik Anabilim Dalı Bilişim Bilim Dalı
- Subjects
Future guess analysis ,Gelecek tahmini ,İletişim Bilimleri ,Statistics ,Epistemology ,Epistemoloji (Bilgi kuramı) ,Prediction models ,Philosophy ,Big data ,Felsefe ,İstatistik ,Scientific information ,Communication Sciences ,Information philosopy - Abstract
Francis Bacon'un `bilgi güçtür` sözü, verinin hayatın hemen hemen her alanında üretildiği ve değerlendiği günümüzde haklılığını ispatlamıştır. Bilgisayar teknolojisinin gündelik yaşama dâhil olmaya başladığı 1940'lardan bu yana hızla yayılması ve her alanda kendisinden söz ettirmesi tüm dünya için yeni bir dönüm noktasının da başlangıcı olmuştur. Bugünün toplumu artık `Bilgi Toplumu` şeklinde tanımlanmaktadır. Bilgiyi elde eden ve onu en iyi şekilde kullanan şirketler, devletler ve bireyler gücün de sahibi konumundadır. Verinin değeri her geçen gün daha da fazla anlaşılmakta ve her alanda üretilen veriler depolanmakta ve analiz edilmeye çalışılmaktadır. Bilgisayar teknolojisindeki gelişmeler, güvenlik kameraları, sensörler, sosyal paylaşım ağları, POS cihazları gibi daha pekçok farklı araç tarafından üretilen veriler klasik yöntemlerle depolanamayacak ve analiz edilemeyecek bir konuma geldiğinde yeni bir kavram; `büyük veri` tartışılmaya başlanmıştır. Klasik istatistiksel yöntemler ve depolama araçlarıyla saklanamayacak ve analiz edilemeyecek boyuttaki veri, petabyte seviyesine ulaşmıştır. Büyük veri kavramı yaklaşık 20 yıldır akademik literatürde kullanılmakta ve tartışılmaktadır. Ancak henüz ne kavramın ismi konusunda ne de kavramın yapısı ve işleyişi konusunda birliktelik sağlanamamıştır. Bu çalışmada, büyük veri kavramı epistemoloji açısından (bilgi kuramı) ele alınmıştır. Büyük veri imkân, ölçüt, kaynak, sınır ve değer bağlamında değerlendirilmiştir. Büyük verinin dünyada kullanımı ve yayılımına ilişkin tespitlerle kavramın kendisine anlam bulduğu alanlar tespit edilmeye çalışılmıştır. Büyük verinin kullanım alanlarına bakıldığında, büyük bir çoğunluğunun geleceği tahmin etmeye ilişkin çalışmalardan oluştuğu görülecektir. Gelecek tahmininin tarihi serüveni içerisinde gelecek bilimle büyük verinin ilişkisi tespit edilmeye çalışılmıştır. Gelecek bilimin temelleri üzerinden büyük verinin ortaya koyduğu tahmin, öngörü ve kestirim kavramları açıklanmaya çalışılmıştır. İstatistiksel analiz yöntemlerinden kestirim modelleri çerçevesinde ise büyük verinin işleyiş yapısı tespit edilmeye çalışılmıştır.Ayrıca, çalışma kapsamında bilim felsefeleri çerçevesinde büyük verinin modern ve postmodern bilimin özelliklerinden hangisine daha yakın olduğu araştırılmıştır. Büyük verinin, modern bilimin belirlenimcilik, nedensellik, örneklem alma, kesinlik ve hipotezden teoriye özelliklerini taşımadığı, postmodern bilimin belirlenimsizlik, korelasyon, örneklemden evrene, kesinsizlik ve teoriden hipoteze özelliklerine daha yakın olduğu görülmüştür.Büyük verinin çalışma boyunca anlatılan olumlu özellikleri dışında bir de karanlık yüzünün olduğu da unutulmamalıdır ancak; çalışmanın epistemoloji ve bilim felsefeleri üzerinden bir değerlendirme içermesi nedeniyle bu konuya kısaca değinilmiştir. Çalışma kapsamında ulaşılan sonuçların ileride bu konu ile ilgili yapılacak olan çalışmalara katkı sağlayacağı, büyük verinin karanlık yüzü hakkında araştırma yapacaklara kavramın anlaşılması konusunda yardımcı olacağı düşünülmektedir. Francis Bacon's `knowledge is power` motto has been validated by today's environment that data is produced and valued in almost every aspect of life since 1940's computer technology has been diffused rapidly in daily life and began to be popular and that was the beginning of a new turning point for the entire world. Today's society is described as `Information Society`. Companies that collect data and use it in the best way, the state and individuals are the owner of the power now. The value of data generated, stored and analyzed in each area has been realized more and more as time goes by. Data produced by advances in computer technology, security cameras, sensors, social media networks and the POS devices that cannot be stored and analyzed by conventional methods have led us to a new point and a discussion of a new concept, `big data` has been started.Data volume has been reached to petabyte levels that cannot be analyzed and by traditional statistical methods and cannot be stored by conventional computer storage techniques. Big data concept has been used and studied in academic articles almost for 20 years but a concensus on the structure and functioning and the name of the concept has not been reached. In this thesis, big data concept has been studied epistemologically and analyzed by its scales, implications, sources, deployments and boundaries. Also we have tried to determine the fields for the use and deployment of this concept in the world.Mostly big data concept has been studied by predictive analytics viewpoints. The relationship of big data and futurology is determined within the context of history of futurology. And also the concepts of estimate, forecasting and prediction have been studied and related to big data concept. The question of how big data functions within the framework of statistical prediction models is tried to be answered.Besides, within the framework of philosophies of science, we have studied the similarities of big data to the features of modern and postmodern sciences. And it was decided that big data hasn't got the determinism, causality, sampling, certainty and hypothesis to theory features of the modern science but it has similarities to the undeterminism, correlation, population, uncertainty and theory to hypothesis features of the postmodern science.Besides the positive points of big data that has been pointed out in our study, one should not forget that big data also has a dark side. But this issue has been briefly addressed because our study is a valuation from epistemological and philosophy of science views. On the long run, it has been thought that our study will contribute to the studies that studies the dark side of big data concept and be helpful. 154
- Published
- 2016
40. Heterojenliğin sağlık sigortalarında toplam hasar modellerine etkisi
- Author
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Şentürk Acar, Aslihan, Karabey, Uğur, and Aktüerya Bilimleri Anabilim Dalı
- Subjects
Generalized linear models ,Aktüerya Bilimleri ,Actuarial Sciences ,Prediction models - Abstract
Hayat dışı sigortada saf prim hasar frekansı ve hasar şiddetinin çarpılmasıyla elde edilmektedir. Genelleştirilmiş doğrusal modeller (GDM) hasar frekansı ve hasar şiddetinin modellenmesinde sıklıkla kullanılan bir yöntemdir. Genelleştirilmiş doğrusal modellerde gözlemlerin birbirinden bağımsız olduğu varsayılmaktadır. Ancak sağlık sigortası gibi bireylerin birden fazla hasar bildirme eğiliminin olduğu bir sigorta verisinde aynı bireyin tekrarlanan hasar tutarları arasında korelasyon olabilir. Tekrarlanan ölçümler arasındaki korelasyon üzerinde etkisi olan değişkenliğin kaynaklarından biri bireyler arasındaki heterojenliktir. Tekrarlanan ölçümlerin modellenmesi için temel olarak iki yaklaşım kullanılmaktadır: Bireye-özgü modeller ve marjinal (kitle üzerinden ortalaması alınmış) modeller. Bireye-özgü modellerde heterojenlik rassal etkiler kullanılarak açık biçimde modellenmektedir. Marjinal modellerde bağımlı değişken bireyler arasındaki heterojenlik göz önüne alınmadan açıklayıcı değişkenlerin bir fonksiyonu olarak modellenmektedir. Marjinal modellerde parametre tahmini için genelleştirilmiş tahmin denklemleri (GTD) kullanılmaktadır. Bu çalışmada, bireyler arasındaki heterojenliğin beklenen toplam hasar tutarı üzerindeki etkisinin araştırılması amacıyla bireylerin toplam hasar tutarı için alternatif bir kestirici önerilmiştir. Bu amaç doğrultusunda, bireyler arasındaki heterojenliğin göz önüne alınması için bireylerin her bir hasarda oluşan tutarları genelleştirilmiş doğrusal karma model (GDKM) ile modellenmiştir. Sağlık sigortası gibi yıllık yenilenebilir sigortada aynı poliçe sahiplerinin yıllar üzerinden takip edilmesinin zor olması nedeniyle marjinal kestirimlere odaklanılmıştır. Bu doğrultuda GDKM'de tanımlanan koşullu ortalamanın rassal etkilerin dağılımı üzerinden ortalaması alınarak marjinal ortalama elde edilmiştir. Hasar şiddeti ile hasar frekansı arasındaki bağımlılığın modellenmesi için hasar sayısı GDKM'de açıklayıcı değişken olarak kullanılmıştır. Hasar sayısı poliçe yılı başında bilinmediğinden hasar sayısı değişkeninin dağılımından yararlanılarak toplam hasar tutarının kestiricisinin kapalı-şekil ifadesi elde edilmiştir.Çalışmanın uygulama kısmında, Türkiye'de faaliyet gösteren özel bir sigorta şirketinden alınan sağlık sigortası verisi kullanılmıştır. Çalışmada önerilen kestirimci modelin kestirim performansı, tek-kısım modeller, iki-kısım modeller, toplam hasar modeli, her bir hasarda oluşan tutarların marjinal model ve doğrusal karma model ile modellendiği kestirimci modeller ile karşılaştırılmıştır. Hasar tutarları lognormal ve gamma dağılım varsayımı altında modellenmiştir. Frekans-şiddet modellerinde hasar sayılarının modellenmesi için sıfır-yığılmalı model, hurdle model ve negatif binom GDM kullanılmıştır. Analiz sonuçlarına göre, sıfır-yığılmalı negatif binom modeli ve hurdle negatif binom modeli sigorta hasar sayılarına negatif binom GDM'den daha iyi uyum göstermiştir. Hasar sayısının açıklayıcı değişken olarak kullanıldığı tüm hasar şiddeti modellerinde istatistiksel olarak anlamlı olduğu görülmüştür. Modellerin kestirim performanslarının değerlendirilmesinde hem iç model doğrulama hem dış model doğrulama yöntemlerinden yararlanılmıştır. Kestirim hatalarının hesaplanmasında hata kareler ortalamasının karekökü ve ortalama mutlak hata kriterleri kullanılmıştır. Ortalama mutlak hataya göre, her bir hasarda oluşan tutarların marjinalleştirilmiş GDKM ile modellendiği çalışmada önerilen kestirimci model diğer kestirimci modellere göre daha iyi performans göstermiştir. Anahtar Kelimeler: kestirim, toplam hasar, genelleştirilmiş doğrusal model, genelleştirilmiş doğrusal karma model, rassal etkiler, marjinal ortalama, korelasyon. Pure premium is obtained as the product of claim frequency and claim severity in non-life insurance. Generalized linear models (GLM) is a commonly used method for modeling claim frequency and claim severity. Observations are assumed to be independent in GLMs. However there may exist correlation between the repeated claim amounts of the same individual in an insurance data such as health insurance where people have a tendency to notify more than one claim. One of the sources of variability that has an impact on correlation among repeated measures is between-individual heterogeneity. There are two main approaches to model repeated measures: Subject-specific models and marginal (population-averaged) models. Heterogeneity is explicitly modeled by using random effects in subject-specific models. In marginal models dependent variable is modeled as a function of explanatory variables without taking into account between-individual heterogeneity. The method of generalized estimating equation (GEE) is used to estimate the parameters of marginal models. In this study an alternative predictor of total claim amount of individuals is suggested to investigate the impact of between-individual heterogeneity on expected total claim amount. In order to do this, claim amounts per claim of the individuals are modeled by generalized linear mixed model (GLMM) to account for the heterogeneity among individuals. Since it is difficult to follow the same policyholders over the years for annually renewable insurance contracts such as health insurance, the focus is on marginal predictions. Accordingly, marginal mean is obtained by averaging the conditional mean in GLMM over the distribution of random effects. To model the dependence between claim severity and claim frequency, claim number is used as an explanatory variable in GLMM. Since the number of claims is not known at the beginning of the policy year, closed-form predictor of total claim amount is obtained by using the distribution of the claim number variable.In application part of the study, a private health insurance data set of a Turkish insurance company is used. The prediction performance of the suggested predictive model is compared to one-part models, two-parts models, aggregate loss model and predictive models in which claim amounts per claim are modeled with marginal model and linear mixed model. Claim amounts are modeled with lognormal and gamma distribution. In frequency-severity models, claim numbers are modeled by zero-inflated model, hurdle model and negative binomial GLM. Based on analysis results, zero-inflated negative binomial model and hurdle negatif binomial model show better fit to insurance claim numbers than negative binomial GLM. Claim number is found to be statistically significant in all severity models in which it is used as an explanatory variable.To evaluate the predictive performance of the models both internal and external model validation methods are used. To calculate prediction errors, root mean square error and mean absolute error criteria are used. Based on mean absolute error purposed predictive model that is obtained by modeling claim amounts per claim by marginalized GLMM showed better performance than the other predictive models. Keywords: prediction, aggregate loss, generalized linear model, generalized linear mixed model, random effects, marginal mean, correlation. 129
- Published
- 2016
41. Yazılım hata kestirim yaklaşımları
- Author
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Sari, Özkan, Kalıpsız, Oya, and Bilgisayar Mühendisliği Anabilim Dalı
- Subjects
Error estimation ,Detection ,Logistic regression analysis ,Prediction models ,Software reliability ,Software metrics ,Computer Engineering and Computer Science and Control ,Bilgisayar Mühendisliği Bilimleri-Bilgisayar ve Kontrol ,Fault - Abstract
Geliştirilen yazılımların bazı hatalar içermesi doğaldır. Önemli olan bu hataların tespit edilebilmesidir. Hataların tespitinde testler önemli bir yer tutmaktadır ancak her zaman bu yeterli değildir. Bu nedenle yazılım hatalarının ve kusurlarının tespit edilebilmesi için etkin yöntemlere ihtiyaç vardır. Yazılım hatalarının, yazılım geliştirme faaliyetlerinin erken safhalarında tespit edilmesinin daha az masraflı olduğu bilinmektedir. Araştırmalara göre, yazılımın teslimi sonrası bir hatanın bulunması ve düzeltilmesi, hatanın yazılımın gereksinim ve tasarım safhalarında bulunmasına kıyasla 100 kat daha masraflıdır. Yazılımdaki hataların ortalama %80'i, yazılım parçalarının (modüllerin) %20'sinde toplanmakta ve yazılımın %50'lik kısmında ise hiç hata bulunmamaktadır. Bu olguya dayanarak, koddaki hatalı olabilecek yerler kodun özellikleri incelenerek tespit edilebilirse hataların daha erken bulunması ve müdahale edilmesi mümkün olacaktır. Bu şekilde, hata eğilimli yazılım parçalarının tespit edilmesiyle test çabaları buralarda yoğunlaştırılabilecek ve eldeki kaynakların hataların bulunma ihtimali yüksek yerlere yönlendirilmesi ile hata tespitinde başarı ihtimali artacak ve hatanın erken tespiti ile büyük kazanç sağlamak mümkün olacaktır.Hata eğilimli yazılım parçalarının tespiti ve hata kestirim faaliyetleri olarak adlandırılan bu çalışmalar bu amaca hizmet ederek, yazılımdaki hataların erken safhada tespitini amaçlamaktadır. Hata eğilimli yazılım parçalarının tespiti yönünde çok çeşitli yaklaşımlar bulunmaktadır. Bu yaklaşımlar hem yöntem hem de başarım açısından farklılıklar göstermektedirler. Tez çalışmasında, belli başlı hata eğilimli yazılım parçalarının tespiti yöntemlerinin incelenmesi ve hata kestirimi için bir etkin bir model geliştirilmesi amaçlanmaktadır. Çalışmamızda lojistik regresyon analizi tabanlı bir yaklaşım benimsenmiş ve kaynak kod metrikleri üzerine yoğunlaşılmıştır.Ortaya konulan model çeşitli halka açık veri setleri üzerinde ve Provus Bilişim Sistemleri A.Ş. bünyesinde geliştirilen yazılımlarda sınanmış ve sonuçlar paylaşılmıştır. For the software being developed, it is natural to have some degree of defects. What is important is to be able to find these defects. Testing activities are essential but testing each fragment of the software is impossible and defects still occur even after several detailed test activities. Therefore, there is a need for effective methods to detect bugs in software. It is well known that it's less expensive to find software defects early on in program. Research shows that finding and fixing a software problem after delivery is often 100 times more expensive than the requirements and design phase. About 80% of the defects come from 20% of the modules, and about half the modules are defect free. Considering these facts, if fault-prone modules are detected, software test efforts can be focused on these modules. By using the limited resources we have on the modules having the highest possibility to have defects, defect detection rate will increase and it will be possible to gain valuable resources by finding defects early.Serving this purpose, activities named as detection of fault-prone modules or defect prediction, help to detect the presence of defects as early as possible in an automated fashion. These approaches differ according to their techniques and success rates. The main approaches in the field will be inspected and an effective model is aimed to be developed in order to predict software entities having bugs. In our study, an approach based on logistic regression analysis and focusing on static software code metrics is utilized.A public bug database and an ATM monitoring software source code which is developed by Provus Bilişim Hizmetleri A.Ş., are used for the creation of the model and to find the performance of the study. 100
- Published
- 2015
42. Slotlu roket/füze modelleri için aerodinamik performans kestirim yöntemlerinin iyileştirilmesi
- Author
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Atak, Bora, Acar, Hayri, and İleri Teknolojiler Ana Bilim Dalı
- Subjects
Aerodynamics ,Havacılık Mühendisliği ,Defense and Defense Technologies ,Guided missiles ,Aeronautical Engineering ,Savunma ve Savunma Teknolojileri ,Prediction models - Abstract
Bu çalışmada, konvansiyonel roket/füzelerin aerodinamik katsayılarının belirlenmesine yönelik geliştirilen hızlı kestirim araçlarının, slotlu (gövde içine katlanabilir kanatlı) roket/füzelerin aerodinamik performans hesaplamalarında da kullanılabilmesi için yapılan iyileştirme çalışmaları anlatılmaktadır. Hesaplamalı akışkanlar dinamiği, bileşen-inşa metodu ve eşdeğer hücum açısı metodu modellerini bir arada kullanan bir yöntem (HAD-BİM) geliştirilmiştir. Bu yöntemin kullanılabilirliğini göstermek amacıyla jenerik bir tanksavar füze belirlenmiştir. Füzeyi oluşturan yüzeyler (gövde, kanat, kuyruk) için farklı uçuş koşullarında hesaplamalı akışkanlar dinamiği analizleri yapılarak aerodinamik veri-tabanları üretilmiştir. Jenerik füzenin farklı konfigürasyonları için bileşen-inşa metodu ile hesaplanan taşıyıcı yüzey-gövde etkileşim faktörleri ve eşdeğer hücum açısı metodu kullanılarak hesaplanan taşıyıcı yüzeylere ait eşdeğer hücum açıları elde edilmiştir. Üretilen veri-tabanları, etkileşim faktörleri ve eşdeğer hücum açıları ile beraber kullanılarak belirlenen konfigürasyonlar için aerodinamik katsayıların hesaplanmasına yönelik kestirimler yapılmıştır. HAD-BİM sonuçları, konvansiyonel roket/füze aerodinamik analizlerinde yaygın olarak kullanılan hızlı kestirim araçlarından biri olan Missile DATCOM sonuçları ve tüm-konfigürasyon hesaplamalı akışkanlar dinamiği sonuçları ile karşılaştırılmıştır. Sonuçlar incelendiğinde geliştirilen yöntemin, slotlu roket/füze kavramsal aerodinamik tasarım ve analizlerinde kullanılabilecek düzeyde olduğu değerlendirilmektedir. In this study aerodynamic fast prediction tools which are developed for conventional rockets/missiles are improved to be used for non-conventional slotted rockets/missiles. A method that uses computational fluid dynamic with component build-up and equivalent angle of attack methods together (CFD-CBU) is developed. A generic anti-tank missile is formed for the validation of this method. The individual databases are generated for the missile components by using computational fluid dynamic analysis in different flight conditions. On the other hand, the lifting surface-body interference factors and equivalent angle of attacks of these components are calculated by using component build-up and equivalent angle of attack methods. The individual databases, interference factors and equivalent angle of attacks are used together to estimate the aerodynamic performance of full configurations. CFD-CBU results are compared with one of the common fast prediction tools Missile DATCOM and computational fluid dynamic analysis of full-configurations. According to the results CFD-CBU method is in a much better agreement with full configuration computational fluid dynamic analysis than Missile DATCOM. As a result, CFD-CBU method can be used to estimate the aerodynamic performance of a non-conventional slotted missile. 87
- Published
- 2012
43. Doğrusal regresyonda çok değişkenli ayarlama (kalibrasyon) sorunu
- Author
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Özyurt, Özlem, Erar, Mehmet Aydın, and Diğer
- Subjects
İstatistik ,Statistics ,Calibration ,Linear regression ,Prediction models - Abstract
DOĞRUSAL REGRESYONDA ÇOK DEĞİŞKENLİ AYARLAMA (KALİBRASYON) SORUNU Özlem Özyurt Hacettepe Üniversitesi, İstatistik Bölümü, İstatistik Ana Bilim Dalı ÖZ Bu çalışmada, bağımsız değişkenlerin sabit olduğu durum için, klasik, ters ve koşullu regresyon teknikleri incelenerek, bağımsız değişkenin iyi önkestirimini (prediction) ve bu önkestirimin güven aralığını veren en iyi model denkleminin bulunması amaçlandı. Birinci bölümde konuya giriş yapıldı. İkinci bölümde, ayarlama kavramı, tek ve çok değişkenli ayarlama, çok değişkenli regresyon, klasik, ters ve koşullu ayarlama teknikleri, tek değişkenli ayarlamada güven aralıkları, çok değişkenli ayarlamada güven bölgeleri ile tek ve çok değişkenli ayarlamada, ayarlama ve önkestirim kümesi için aykırı değer kavramları incelendi. Üçüncü bölümde çok değişkenli doğrusal ayarlama uygulaması için geliştirilen MATLAB programı anlatıldı. Yapay veriler üzerinden geçerlilik incelemesi yapıldı. Gerçek veriler üzerinde klasik, ters ve koşullu ayarlama modelleri incelenerek verileri en iyi açıklayan modeller elde edildi. Ayrıca güven aralıkları bulundu, ayarlama ve önkestirim kümelerinde artık incelemesi yapıldı. Anahtar Kelimeler: Kalibrasyon, ters regresyon, önkestirim, koşullu kalibrasyon Danışman: Doç.Dr.Aydın ERAR, Hacettepe Üniversitesi, İstatistik Bölümü, İstatistik Ana Bilim Dalı MULTIVARIATE CALIBRATION PROBLEM IN LINEAR REGRSSION Özlem Özyurt Hacettepe University, Department of Statistics, Statistics Section ABSTRACT In this work, for the case that independent variable is fixed, classical, inverse and conditional calibration techniques are studied on application data which it was obtained as experimental results and artificial data. It is aimed to conclude the best model for prediction of the independent variables and the confidence areas of this prediction. The first chapter is introduction. In the second chapter, calibration object, univariate and multivariate calibration, multivariate regression, classical, inverse and conditional calibration techniques, confidence interval in univariate calibration, confidence areas in multivariate calibration, and research for calibration and prediction data in univariate and multivariate calibration are explained. In the third chapter, MATLAB program which was developed for multivariate calibration application is explained. The validity is examined on the artificial data. On the data which are obtained from experiments, classical, inverse and conditional calibration models which explain the data best are found. In addition, a search on confidence areas and residuals are done. Keywords: Calibration, inverse regression, prediction, conditional calibration Advisor: Ass.Prof. Aydın ERAR, Hacettepe University, Department of Statistics, Statistics Section 70
- Published
- 2002
44. Rekor değerlerine ilişkin ön kestirimlerin belirlenmesi ve bir uygulama
- Author
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Altin, Arzu, Kurt, Günseli, and İstatistik Anabilim Dalı
- Subjects
İstatistik ,Statistics ,Record values ,Prediction models - Abstract
ÖZET Bu tezde öncelikle rekor istatistiklerinin tarihçesi ele alınmış, daha sonra rekor zamanları ile rekor değerlerinin dağılımları teorik olarak ayrıntılarıyla incelenmiştir. Gözlemlenen rekor değerleri yardımıyla, rekorların geldiği dağılımın parametreleri kestirilmiş ve izleyen rekor değerinin meydana gelme olasılığı belirlenmiştir. Teorik olarak incelenen rekor, değerleri ile ilgili uygulama Eskişehir bölgesine su sağlayan barajlara gelen su miktarları dikkate alınarak yapılmıştır. SUMMARY In this thesis firstly the history of record statistics were taken into consideration and then record times and the distribution of record values were evaluated theoretically in details. Via the help of observed record values the parameters of distribution from which records come through are inferred and the possibility of happening of the following record values are determined. The application assaciated with the record statistics observed theoretically were evaluated with the practical application through which coming amount of the water the data of the dams supplying water to the Eskişehir area. 134
- Published
- 2001
45. Yazılım geliştirme metrikleri ve yazılımD proje izleme sistemi geliştirimi
- Author
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Sultanoğlu, Mustafa Sencer, Karakaş, Ümit, and Diğer
- Subjects
Software engineering ,Software development ,Computer softwares ,Prediction models ,Computer Engineering and Computer Science and Control ,Bilgisayar Mühendisliği Bilimleri-Bilgisayar ve Kontrol - Abstract
IV ÖZET Bir üretim alanının mühendislik adı ile anılabilmesi için, söz konusu üretim alanında, ürünün; üretimin özelliklerinin, emek ve hammadde maliyetinin önceden kestirilebilmesi, alternatif üretim maliyetlerinin çıkarılabilmesi, işin teslimi sırasında teslim alınan işin önceden belirlenen özelliklere uygunluğunun sınanabilmesi gerekir. Yazılım geliştirmenin de mühendislik olarak anılabilmesinin temel koşullarından biri önkestirim yöntemlerinde ve metriklerinde, kabul koşullarında anlayış birliği sağlamaktır. Bu amaçla tezde öncelikle, yazılım metrikleri, geliştirme emeği önkestirim yöntemleri ve yazılım kalitesi incelenmiş, 1970'li yılların sonundan günümüze kadar gelişimleri araştırılmış, eksiklikleri belirlenmiştir. Bunların belli başlıları arasında COCOMO'81 ve devamı COCOMO 2.0, Fonksiyon Puanı ve türevleri bulunmaktadır. Son zamanlarda ortaya çıkan, nesneye yönelik programlama ortamları için geliştirilen metrikler emek önkestirimine yönelmemektedirler. Tez kapsamında, Yazılım Mühendisliği teorisi ile pratiği arasındaki farkları gözlemlemek amacıyla kabul aşamasında yada kabul edilmiş beş yazılım üzerinde alan çalışması yapılmıştır. Alan çalışmalarında yazılım müşterileri ve geliştiricileri ile görüşülmüş, yorumları izlenmiştir. Üç yazılımın kaynak kodu ve çalışması incelenmiş, kalite belirleyici nitelikleri araştırılmıştır. Tez çalışmasında, ayrıca, yazılım maliyeti önkestirim yöntemlerinin teorisini desteklemek üzere YazılımD sl.O ( Yazılım Değerlendir ) adlı bir program geliştirilmiştir. Dört tane kabul görmüş önkestirim yöntemi ve üç kişinin yaptığı kestirimler birlikte değerlendirilmiş, kişilerin deneyimleri ve yazılım yaşam döngüsünde bulunulan yere göre değişen kestirimdeki belirsizliği de dikkate alarak ortak kestirim üretilmiştir. YazılımD ile hem önerilen birden fazla kestirimin birlikte kullanılması, hem de yazılım yaşam döngüsü içinde çeşitli aşamalarda maliyet kestiriminin yapılarak durumun izlenip değerlendirilmesi, belirsizlik de göz önüne alınarak, kolaylaşmaktadır. ABSTRACT For production in any domain to be considered a feat of engineering, the essential conditions to be met are: to estimate manpower and raw material costs necessary for production as well as the technical characteristics of the product, to estimate alternative costs of production, and to test the product's congruity with the specifications in the contract at the time of delivery. Subsequently, one of the essential conditions to be fulfilled for software development to be considered engineering is to reach, a priori, an aggreement of cost estimation methods, metrics and software acceptance criteria. Accordingly, in this thesis, existing software metrics, software development effort estimation methods and software quality are researched; their development since the end of the '70s is investigated; and their deficiencies are determined. Some principal methods among them are COCOMO'81 and its successor COCOMO'2.0, Function Point and its derivatives. Recently emerged metrics for object oriented programming are riot yet intended for estimating manpower requirements. In the coverage of this thesis, in order to observe the differences between theoretical and practical Software Engineering, case studies are performed on five different software which are on acceptance phase or already accepted. Interviews are held with various software customers and developers. Their comments are noted in the case studies. Source code and execution of three different software are investigated and their quality characteristics are analysed. In addition, in the preparation of the thesis, in order to support the theory of software cost estimation methods, a program called YazılımD sl.O (Software Evaluate) is developed. Results based on four accepted estimation methods together with estimations done by three individuals are evaluated and, taking into consideration the level of experience of the individuals and the uncertainty in respect to the phase of the software life cycle, a combined estimate is calculated. YazılımD is not only facilitates the proposed use of more than one estimation, but also enables the observation and evaluation of production conditions by making cost estimates available during various phases of the software life cycle, while allowing for the uncertainty factor. 146
- Published
- 1999
46. HF bandında gök dalgası yayılımı
- Author
-
Haşimoğlu, Serap, Yazgan, Erdem, and Diğer
- Subjects
Wave propagation ,Elektrik ve Elektronik Mühendisliği ,HF band ,Ionosphere ,Prediction models ,Electrical and Electronics Engineering - Abstract
In this thesis sky wave propagation in HF band is analyzed and some predictions are made for sound broadcasting. The reflecting layer for HF is ionosphere. Because of this, the effects of ionospheric properties on propagation is introduced. Then the sky wave propagation is seperated into two parts as point to point and point to area. For point to point propagation REC533A, REC533POINT, VOACAP programs, for point to area propagation REC533AREA, FIELDPLOT, VOAAREA programs are used for prediction. The input parameters of the programs are the ones used by TRT for sound broadcasting. The results of predictions are analyzed and the programs are compared. Also the antenna types and the way of selecting the appropriate antenna is introduced. Key words: Ionosphere, HF band, propagation, prediction. ABSTRACT In this thesis sky wave propagation in HF band is analyzed and some predictions are made for sound broadcasting. The reflecting layer for HF is ionosphere. Because of this, the effects of ionospheric properties on propagation is introduced. Then the sky wave propagation is seperated into two parts as point to point and point to area. For point to point propagation REC533A, REC533POINT, VOACAP programs, for point to area propagation REC533AREA, FIELDPLOT, VOAAREA programs are used for prediction. The input parameters of the programs are the ones used by TRT for sound broadcasting. The results of predictions are analyzed and the programs are compared. Also the antenna types and the way of selecting the appropriate antenna is introduced. Key words: Ionosphere, HF band, propagation, prediction. 113
- Published
- 1999
47. Arıma ve var modelleme yöntemlerince üretilen önkestirim modelleri ve Türkiye ekonomisi üzerine bir uygulama
- Author
-
Baytaş Deriş, Füsun, Cinemre, Nalan, and İstatistik Anabilim Dalı
- Subjects
Turkish economy ,İstatistik ,Statistics ,Prediction models - Abstract
ÖZET Bu çalışmada, kısa ve orta dönem için geleceğe yönelik kestirimlere ulaşmak üzere zaman serisi analizlerinde yoğun bir biçimde kullanılan ve bu konuda güncelliğini koruyan ARIMA ve VAR modeller incelenmektedir. Ayrıca, bu modellerin Türkiye ekonomisindeki bazı temel makro değişkenlere uygulaması yapılmaktadır. Çalışmada incelenen analiz yöntemlerinin yapılan, doğal olarak birbirlerinden farklılık göstermektedirler. Öyle ki, Tek Değişkenli Box- Jenkins Analizi veya ARIMA Modellemesi olarak adlandırılan yöntem; zaman serisiyle ifade edilebilen herhangi bir değişkenin geçmişte izlediği davranışları esas almaktadır. Bu davranışların ileride de değişmeyeceği varsayımı üzerine kurulan yöntem uyarınca elde edilen önkestirimler arasından İMKB endeksinin dışında kalan diğer ekonomik büyüklüklerin özellikle kısa dönemde oldukça büyük bir başarı sergilediği görülmektedir. Diğer bir deyişle, ARIMA modeller çerçevesinde enflasyon oranının, dolar kurunun, sanayi üretim endeksinin ve M2'nin gerçekleşen değerlerine yakın ve tutarlı sonuçlara ulaşılabilmektedir. Öte yandan, teorik olmayan Çok Değişkenli Zaman Serisi Analiz yöntemlerinden birisi olan VAR Modelleme yaklaşımı, modele katılacak her bir değişkenin hem kendisinin hem de diğer değişkenlerin geçmiş değerlerinden etkilendiği varsayımına dayanmaktadır. Buna göre. 1986 yılının Ocak ayından başlayan ve 1995 yılı Haziran ayma kadar olan dönem için derlenen aylık verilerden yola çıkılarak kurulan beşli otoregresif bir model aracılığıyla üretilen önkestirimler de çalışmada yer almaktadır. Kullanılan her iki yöntemin ürettiği Önkestirimlerin performansları karşılaştırıldığında; ARIMA modellerin önkestirim hatalarının, kısıtsız VAR modeline ilişkin önkestirim hatalarından daha küçük olduğu saptanmaktadır. Uygulama sonucunda elde edilen bu bulgular doğrultusunda yapılan değerlendirme, önkestirim konusunda ARIMA modellerin VAR modelinden daha başarılı olduğunu ortaya koymaktadır. SUMMARY In this study, for the purpose of reaching the short and middle-terms forecasting ARIMA and VAR Models which ared used very intensively in Time Series Analysis have been examined. In Turkish economy, an application of these models has been done to some macro econometrics variables. The structure of the techniques examined in this study are naturally different. The Univariate Box- Jenkins Analysis, which are also called ARIMA modelling, is based on the behaviours of a variable in the past time. The forecasts, which are obtained by assuming the invariability of these behaviours in the future are very successfull especially in short terms except İMKB index. In another words, by using ARIMA models, one can obtain very unbiased and consistent forecasts of Wholesale Prices Index (WPI) and inflation ratio, average US Dollar exchange rate, Industrial Production Index and M2. On the other hand, VAR Modelling is a atheoritical multivariate time series analysing technique and assumes that every single variable is affected both by its own and the other variables past values. In this study, five variable autoregressive model has been examined for the monthly data, from January 1986 to June 1995 (114 months). The study also presents this model's forecasts. As a result, the study compares the performances of these two techniques- ARIMA and VAR Models- and it has been found that the forecasts errors oî ARIMA models are smaller than those of VAR Models. Net, the preference is to examine every variables seperately by UUMA models. 194
- Published
- 1996
48. Faktör analizinin kestirim amaçlı kullanımı (Seçime katılma ve belli bir partiye oy vermede bazı ekonomik göstergelerin etkisinin analizi)
- Author
-
Durucasu, Hakan, Yüzer, Fuat, and Diğer
- Subjects
İstatistik ,Statistics ,Parameter estimation ,Factor analysis ,Prediction models ,Regression analysis - Abstract
II ÖZET önkestirim modellerinin de faktör analizi başlığı altında ele alınabileceğini göstermeyi amaçlayan bu çalışmada, faktör analizi ve regresyon analizi arasındaki benzerlik ve farklılıklar incelenmiştir. Veri ve korelasyon matrislerine ilişkin faktörleme yaklaşımları ele alınmış ve faktör analizinin yapısal analizine yer verilmiştir. Rank indirgemeye ilişkin temel bilgiler verilmiş ve rânk indirgeme yaklaşımının centroid tekniklerindeki rolü ve matematik ayrıntıları ele alınmıştır. Rank indirgemenin parametre kestirim problemlerinde de geçerli bir yaklaşım olduğu vurgulanarak, geliştirilen bilgisayar programları ile faktör analizinin kestirim yaklaşımının 82 sonrası seçimlerde elde edilen veriye uygulaması gerçekleştirilmiştir. III ABSTRACT In this study which aims to show prediction models that can be considered under the title of factor analy sis, the similarities and differences between regression analysis and factor analysis are examined. Factoring approaches which are related to the data and correlation matrix are studied and the structural analysis of factor analysis has been mentionned. Basic knowledge of rank reduction is given and the role of rank reduction approach to the cenÇroid technics and mathematical details are handled. Pointing out the validity of rank reduction in parameter estimation problems, estimation approach of factor analysis is practised with devoloped computer programs on the data obtained from elections for the years after 82. 164
- Published
- 1995
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