Hardware In The Loop Simulation Of Underactuated Mechanical Systems

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2007Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2007Hava ve Uzay araçları gibi kritik sistemler için kontrolör tasarımında asıl sisteme benzer ve gerçek-zamanlı (Real-Time) çalışabilen benzetim sistemleri; ileride çıkabilecek birçok arızanın, henüz tasarım ve test aşamasında çözülmesini sağlamaktadır. Bu çalışmada, gerçek-zamanlı benzetim yapabilen ve klasik benzetim yöntemlerine göre asıl sistem davranışına daha yakın sonuçlar veren Donanım Çevrimli Benzetim (Hardware-in-the-loop Simulation) yöntemi kullanılarak, Eksik Uyarımlı (Underactuated) mekanik sistemlerin benzetimi üzerine çalışılmıştır. Gerçeklenen sistem üzerinde ilk olarak, 1-Serbestlik derecesine sahip olan basit sarkaç modelinin benzetimi yapılmıştır. Platform üzerinde en fazla 2-Serbestlik derecesine sahip mekanik sistemler test edilebilmektedir. Donanım Çevrimli Benzetim yöntemine dayalı bu platform sayesinde farklı mekanik sistemlerin, model üzerinde yapılacak değişiklikler ve bazı sistem parametrelerinin ayarlanmasıyla, gerçek-zamanlı benzetimi yapılabilir.In controller design for the critical systems like aircrafts and space vehicles, real-time simulation systems provides to designers to seize the failures that will be possible for the designed system, during the test and design process. In this study, underactuated mechanical systems simulation is processed using Hardware-in-the-loop Simulation technique for its real-time simulation and more precise results superiorities with respect to conventional simulation techniques. A simple pendulum model is simulated in the implemented system as a 1-degree-of-freedom system. Mechanical systems, which have 2-degrees-of-freedom, could be tested on the platform. Different kinds of mechanical systems could be simulated on this platform by means of Hardware-in-the-Loop simulation technique, only requires some parameter tuning process.Yüksek LisansM.Sc

Fragmented QRS predicted major adverse cardiovascular events in patients with coronary artery disease and percutaneous coronary intervention, 10-years of follow-up

Aim Identifying high-risk groups in patient with coronary artery disease (CAD) is critical for predicting future adverse events. fQRS has been shown to be related to major cardiovascular adverse events (MACE) in patients with CAD. However, predictive value of fQRS for more than 5 yrs has not been evaluated. This study examined the predictive value of fQRS in patients with CAD and percutaneous coronary intervention during a 10-yrs period. Material and methods Patients with CAD and percutaneous coronary intervention between March 2007 and May 2009 were included the study. An electrocardiogram was recorded following percutaneous coronary intervention and analyzed for the presence of fQRS. The fQRS pattern was defined as an additional spike inside the QRS complexes of at least two consecutive leads. Patients were followed for 10 yrs. A MACE was all-cause mortality or new-onset decompensated heart failure. Patients were divided into two groups according to presence or absence of MACE, and their clinical variables were compared. Results Of 1261 patients included in the study, MACE developed in 374 (29.6%). MACE (+) patients were older (p<0.001), more likely to have diabetes mellitus (p=0.003), fQRS (p<0.001), and ST-elevated myocardial infarction (STEMI) (p<0.001). Multivariable Cox regression analysis revealed that age (p<0.001), STEMI (p=0.001), fQRS (p=0.017), and elevated serum creatinine (p=0.001) were independent predictors of MACE. Conclusion The presence of fQRS predicted MACE during 10 yrs of follow-up of patients with CAD and percutaneous coronary intervention

Mikro derin çekme işleminde numune ve tribolojik boyut etkisinin sonlu eleman analiziyle incelenmesi

Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2013Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2013Bu çalışmada nümune boyut etkisi ve sürtünme katsayısının bir mikro derin çekme parçasının şekillendirilmesine etkisi sonlu eleman analizi yardımıyla incelenmiştir. Boyut etkisini incelemek amacıyla 0.1 , 0.2 ve 1 mm kalınlıklarında 3 farklı sac kullanılmış; kalıp ve zımbaya ait ölçüler de her bir işlemde aynı oranda arttırılarak 3 farklı sonlu eleman modeli oluşturulmuştur. Sac kalınlığının azaltılmasıyla eşdeğer von Mises gerilmesi değerlerinin arttığı tespit edilmiştir. Tribolojik boyut etkisinin belirlenmesi amacıyla yapılan analizlerde ise sürtünme katsayısının arttırılması durumunda eşdeğer gerilmelerde artış gözlenmiş ve 0.1 mm sac kalınlığı için en yüksek eşdeğer gerilme değeri elde edilmiştir.Effects of specimen size and coefficient of friction on micro-deep drawn part have been investigated by means of finite element analysis. To this goal, blanks with three different thicknesses, namely 0.1, 0.2, and 1 mm, have been used. Furthermore, dimensions for die and punch are increased by same factor in FE models. Results showed that, equivalent von Mises stress values are increased when thinner sheet gauges are used. Similarly, increased equivalent von Mises stress values are observed with increasing coefficient friction values, and the highest values are obtained for the smallest sheet thickness

Monthly Electricity Generatıon Forecast in Solar Power Plants with LSTM

Today, with the intensive use of electrical devices, the need for electricity has increased. Fossil fuels are generally used to meet this need. However, considering the damage caused by fossil fuels to the environment, governments make various incentives for renewable energy sources. The incentives of countries for solar power plants are quite large. Recently, there are many investors who want to build solar power plants. The sunshine duration of our country is quite high. And the fact that the climatic conditions are efficient for the generation of electricity attracts many investors. However, the installation of these power plants is quite costly. It is possible to predict the amortization periods of these costs with the ever-developing artificial intelligence technology. In this study, the energy data to be produced in the future is estimated by using real solar power plant data with machine learning algorithms. Data, take from solar power plants owned by Humartaş Energy company. In the study, predictions and analyses were made using the LSTM (Long Short-Term Memory) method, which is one of the artificial neural networks. The error rate of the study between 1% and 15%. It is foreseen that studies will also be implemented with other renewable energy sources such as wind, geothermal, hydraulic energy data in the coming stages

Left atrial dimension to left ventricle ejection fraction ratio can predict longterm major adverse events ın patients with acute coronary syndrome

Background: It is critical to specify the high-risk group in acute coronary syndrome following percutaneous coronary intervention. Left atrial diameter and Left ventricle ejection fraction are functional echocardiographic parameters for risk classification thanks to easy obtainable, cheap, and non-invasive nature. However, major adverse cardiovascular events may be predicted less than actual where ejection fraction or left atrial diameter are in the normal range. We aimed to assess the left atrial diameter to ejection fraction ratio for major adverse cardiovascular events prediction in acute coronary syndrome. Materials and Methods: Individuals with acute coronary syndrome were included in the study. Atrial diameter and ejection fraction parameters were obtained at admission. The left atrial diameter to left ventricular ejection fraction ratio was calculated through atrial diameter dividing by ejection fraction, and the relationship between new-onset heart failure and all-cause mortality with this ratio was investigated for two years period. Results: The mean age of total 262 patients were 62.1±11.5 years. Thirty-nine (18.9 %) of patients were female and major adverse cardiovascular events occurred in 73 (28%) of the patients. In the backward multivariable Cox regression analysis, age [Hazard ratio (HR)=1.039, 95%CI:1.017-1.060, p<0.001], Killip class [HR=2.099, 95%CI:1.011-4.365, p=0.045], serum creatinine level [HR=2.202, 95%CI:1.247-3.811, p=0.003], and left atrial diameter to left ventricular ejection fraction ratio [HR=1.029, 95%CI:1.019-1.038, p<0.001] were revealed to be independent predictors of major adverse events. Conclusion: Left atrial diameter to left ventricular ejection fraction ratio were predictors of two years new-onset heart failure and mortality in acute coronary syndrome. This novel practical index may provide better prediction for adverse events in all patient groups.Amaç: Akut koroner sendromlu hastalarda perkütan koroner girişim sonrası yüksek riskli grupların belirlenmesi oldukça önemlidir. Sol ventrikül ejeksiyon fraksiyonu ve sol atrium çapı, kolay elde edilebilebilir, ucuz ve invaziv olmaması nedeniyle risk sınıflandırması için fonksiyonel ekokardiyografik parametrelerdir. Bununla birlikte, majör istenmeyen kardiyovasküler olaylar, ejeksiyon fraksiyonu veya atrium çapının normal aralıkta olduğu durumlarda gerçek olandan daha az tahmin edilebilir. Bu nedenle akut koroner sendrom hastalarında majör istenmeyen olay öngörüsü için sol atrium çapının sol ventrikül ejeksiyon fraksiyonuna oranının değerlendirilmesini amaçladık. Materyal ve Metod: Çalışmaya akut koroner sendrom tanısı almış hastalar dahil edildi. Tüm hastalardan sol ventrikül ejeksiyon fraksiyonu ve sol atrium çapları parametreleri başvuru sırasında elde edildi. Sol atrial çapın sol ventrikül ejeksiyon fraksiyonuna oranı, sol atriyal çapın ejeksiyon fraksiyonuna bölünmesi ile hesaplandı ve 2 yıllık takiplerde tüm nedenlere bağlı ölüm ve yeni başlayan kalp yetmezliği ile olan ilişkisi incelendi. Bulgular: Toplam 262 hastanın ortalama yaşı 62.1±11.5 yıldı. Hastaların 39'u (%18.9) kadındı ve major istenmeyen kardiyovasküler olay 73 (%28) hastada meydana geldi. Geriye dönük çok değişkenli Cox regresyon analizinde, yaş [Hazard ratio (HR)=1.039, 95%CI:1.017-1.060, p<0.001], Killip sınıfı [HR=2.099, 95%CI:1.011-4.365, p=0.045], serum kreatinin düzeyi [HR=2.202, 95%CI:1.247-3.811, p=0.003], ve sol atrial çapın sol ventrikül ejeksiyon fraksiyonuna oranı [HR=1.029, 95%CI:1.019-1.038, p<0.001] major istenmeyen olayların bağımsız prediktörleri olarak bulundu. Sonuç: Sol atrial çapın sol ventrikül ejeksiyon fraksiyonuna oranı, akut koroner sendrom hastalarında 2 yıllık yeni tanı kalp yetmezliği ve ölümün bağımsız prediktörleriydi. Bu yeni pratik index istenmeyen olayların öngörülmesi için tüm hasta gruplarında daha fazla öngörü sağlayabili

A Matrix Decomposition Method for Optimal Normal Basis Multiplication

We introduce a matrix decomposition method and prove that multiplication in GF(2^k) with a Type 1 optimal normal basis for can be performed using k^2-1 XOR gates irrespective of the choice of the irreducible polynomial generating the field. The previous results achieved this bound only with special irreducible polynomials. Furthermore, the decomposition method performs the multiplication operation using 1.5k(k-1) XOR gates for Type 2a and 2b optimal normal bases, which matches previous bounds

Incidental foreign language vocabulary acquisition from social network games

It is widely known that young people use social networks not only for sharing and communication purposes but also as means of entertainment and pleasure by playing various online games. Furthermore, there is a common belief among pedagogues that spending valuable amount of time on social networks to play online games can lead to negative academic, personal and social outcomes. However, the findings of this study based on survey conducted with 248 high school students reveal that social network games can also have pedagogical benefits. The results of this research have shown that students can incidentally learn an important number of foreign language words from popular online games on social networks.