A comparative study on human activity classification with miniature inertial and magnetic sensors

Ankara : The Department of Electrical and Electronics Engineering and the Institute of Engineering and Science of Bilkent University, 2011.Thesis (Master's) -- Bilkent University, 2011.Includes bibliographical references leaves 57-67.This study provides a comparative assessment on the different techniques of classifying human activities that are performed using body-worn miniature inertial and magnetic sensors. The classification techniques compared in this study are: naive Bayesian (NB) classifier, artificial neural networks (ANNs), dissimilarity-based classifier (DBC), various decision-tree methods, Gaussian mixture model (GMM), and support vector machines (SVM). The algorithms for these techniques are provided on two commonly used open source environments: Waikato environment for knowledge analysis (WEKA), a Java-based software; and pattern recognition toolbox (PRTools), a MATLAB toolbox. Human activities are classified using five sensor units worn on the chest, the arms, and the legs. Each sensor unit comprises a tri-axial gyroscope, a tri-axial accelerometer, and a tri-axial magnetometer. A feature set extracted from the raw sensor data using principal component analysis (PCA) is used in the classification process. Three different cross-validation techniques are employed to validate the classifiers. A performance comparison of the classification techniques is provided in terms of their correct differentiation rates, confusion matrices, and computational cost. The methods that result in the highest correct differentiation rates are found to be ANN (99.2%), SVM (99.2%), and GMM (99.1%). The magnetometer is the best type of sensor to be used in classification whereas gyroscope is the least useful. Considering the locations of the sensor units on body, the sensors worn on the legs seem to provide the most valuable information.Yüksek, Murat CihanM.S

Sürücü koltuğu simülatörü mekanik ve tahrik sistemi tasarımı

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Simülatörler özellikle gerçek sistem üzerinde denenmesi tehlikeli veya imkansız olan eğitim konuları için ya da halihazırda olmayan sistemlerin davranışlarının gözlenmesi ve incelenmesi için kullanılır. Araç sürücü koltuğu simülatörü yapılması, başta sürücü kurslarında verilen pratik eğitimin daha ekonomik, verimli ve güvenli bir şekilde yapılmasını sağlar. Aynı zamanda çevresel etkileri de azaltacaktır. Bu doğrultuda tasarlanması planlanan sistem için önce literatür araştırması yapılmıştır. Simülatör; üç ayrı bölümden meydana gelecek şekilde tasarlanmıştır. Bu bölümler; Mekanik, Elektronik-Kontrol ve Tahrik Sistemidir. Tasarım öncesinde insanın anatomik özellikleri düşünülerek mekanik sistemin boyutlandırılması yapılmıştır. Mekanik sistem uygun bir zemine yerleştirilecek ve üç boyutlu sanal olarak tasarlanmış sürüş güzergahına uygun hareketler yapacak şekilde Elektronik-Kontrol ve Tahrik sistemleri projelendirilecektir. Burada iki farklı tahrik sistemi kullanılacaktır. Birincisinde mekanik sistemin tahriki hidrolik sistem, ikincisinde ise elektromekanik sistem tarafından sağlanacaktır. Bu iki farklı tahrik sisteminin simülatöre uygulanması, ekonomikliği ve verimliliği karşılaştırılacaktır.Simulators are especially used on educational subjects which are too dangerous or impossible to try on the real system or the observation and examination of unprepared systems' behaviors. The production of the Driver's Seat Simulator provides a more economical, more efficient and safer version of the practice lessons given at the driving schools. In this direction, first, literature research was made for the system planned for designing. The simulator was designed to be formed by 3 separate parts. These parts are Mechanic, Electronic-Control and Propulsion Systems. Before the designing the size of the system was calibrated by considering the anatomic structure of the human body. The Mechanical System will be placed in a proper base, the Electronic-Control and the Propulsion System will be projected with the ability to move appropriately to the 3 dimensional virtually designed driveway. There will be 2 different Propulsion Systems used in this set-up. At the first one the propulsion will be provided by the propulsionary hydraulic system of the mechanical system and at the second one the propulsion will be provided by the electromechanical system. The application of these two different propulsion systems will compare the productivity and the affordability

Initiatives and New Trends Towards Stem Education in Turkey

STEM (Science, Technology, Engineering, Mathematics) Education; Is an educational approach that many countries in the world have included in their curricula that allow learners to view the knowledge they learn in science, technology, engineering and mathematics courses, aiming at transforming theoretical knowledge into practice, product and innovative inventions. It is aimed to be able to adapt easily to the qualities of the business life thanks to these skills when the STEM trained individuals enter into the business world, as well as being an approach that is based on giving the skills of STEM education, production and invention. Within the scope of the study, attempts were made to investigate the initiatives and new trends of STEM education from 2010 until the day. Document analysis and thematic content analysis (meta-synthesis) method was used in the research process. Thematic content analysis; Analyze, synthesize and interpret the findings of more than one research on the same subject, with a critical point of view, in contrast to the theme or templates specified and raw data. During the research; Articles, theses, reports and reports which are reached from various sources in the national and international literature have been examined and a wide-scale resource has been created by considering every point related to the contents of the work. The results of the research were examined under various headings and a broad framework was established and recommendations were made

Determination and evaluation of acidity constants of some imidazole and thiazole linked acetamide compounds

In this work, the effect of substituents on the acidity constants of some acetamide derivatives was investigated. The acidity constants of nine acetamide derivatives were determined at 25 °C using a UV spectrophotometric method. When the molecules possessed different substituents the values of the acidity constants changed from 6.01 to 8.22 for the first protonation and from 3.07 to 4.73 for the second protonation. The first protonation under these circumstances was observed to occur on the nitrogen atom of the 2-mercaptoimidazole ring. The second protonation was observed to occur on the nitrogen atom of the thiazole ring

Sample size, power and effect size revisited: simplified and practical approaches in pre-clinical, clinical and laboratory studies

Calculating the sample size in scientific studies is one of the critical issues as regards the scientific contribution of the study. The sample size critically affects the hypothesis and the study design, and there is no straightforward way of calculating the effective sample size for reaching an accurate conclusion. Use of a statistically incorrect sample size may lead to inadequate results in both clinical and laboratory studies as well as resulting in time loss, cost, and ethical problems. This review holds two main aims. The first aim is to explain the importance of sample size and its relationship to effect size (ES) and statistical significance. The second aim is to assist researchers planning to perform sample size estimations by suggesting and elucidating available alternative software, guidelines and references that will serve different scientific purposes

The effect of surface roughness on push-out force in aluminum outer cage bushings

Bilyalama yöntemi parçalar üzerinde pürüzlülüğü arttırmak, atık gerilmeleri önlemek, yorulma ve çatlak oluşumu gibi durumları engellemek için yapılan bir işlemdir. Çaplama işlemi ise süspansiyon sistemini oluşturan parçalardan birisi olan burçların üretimi sonrasında oluşan ölçü farklılıklarını engellemek ve burcu uygun ölçüye getirmek için uygulanan bir yöntemdir. Bu çalışmada, alüminyum dış kafese sahip olan burçlarda bilyalama ve çaplama işlemleri farklı sıralamalar ve farklı parametreler ile gerçekleştirilerek yüzey pürüzlülükleri farklı burçlar elde edilmiştir. Elde edilen burçlar ile gerçekleştirilen montaj işlemleri sonrasında, salıncak üzerindeki çıkma yükleri incelenerek kayıt altına alınmıştır. Artan yüzey pürüzlülüğüne bağlı olarak burçların yuvalarında kayma esnasında karşılaşacağı sürtünme kuvvetleri arttığı için çıkma yüklerinde artış beklenmektedir. Çıkma yükleri incelendiğinde artan yüzey pürüzlülüğünün çıkma yüklerini arttırdığı gözlemlenmiştir.Shot peening is a process that used to increase surface roughness, decrease residual stress and prevent fatigue and crack propogation. On the other hand, gauging is a process to prevent differences between bush dimensions that used in the suspension system. In this study, shot peening and gauging are applied with different sequence and parameters to get bushes with various surface roughness. After assembly process of these bushes, push out forces are recorded. The push out force increases with respect to increasing surface roughness

A New Formulation For The Fundamental Period Of Reinforced Concrete Planar Shear Walls

The reinforced concrete shear wall system has become a popular structural component for lateral resistance in buildings and base shear of these structures has a vital effect on the earthquake induced lateral forces. The fundamental period of structures is used in most building codes to determine the lateral forces. However, accurate computation of period is not an easy task at the design stage. The main objective of this study is to evaluate the empirical easy-to-use equation for the calculation of fundamental periods of concrete planar shear walls. Genetic programming has been used to generate the proposed formula. Finite element analysis, were carried out for various shear walls having a variety of height and length and the results were used to develop the proposed formula. The outcomes of formula are compared with the results from equations in the seismic codes and finite element analysis. The comparison results indicate good agreement with finite element analysis and show better performance than codes

Bone height measurement of maxillary and mandibular bones in panoramic radiographs of edentulous patients

Objectives. The purpose of this in vitro study were to determine variation in maxillary and mandibular vertical measurements and to assess vertical bone loss made from panoramic radiographs in edentulous measurements. Study Design. In this descriptive study, a total of 600 panoramic radiograph’s of edentulous patient were examined. The mean ages of edentulous patients were 31 and 87 years respectively. Measurements were made from reference lines drawn from anatomic landmarks on standardized panoramic rediographs. All radiographs were made using a standardized manner by the same technician. Twelve sites were measured on every panoramic radiograph whenever possible, five sites in the maxilla and seven sites in the mandible. Results. In the maxilla all vertical measurements distance were significantly greater in the edentulous men than in the edentulous women (p<0,05). In the mandible all vertical measurements distance were significantly greater in the edentulous men than in the edentulous women (p<0,05). Conclusion. The results of this study may guide clinicians to make primer decision of implant insertion area for implant supported prosthesis in edentulous patient

The pain symptoms and mass recurrence rates after ovarian cystectomy or uni/bilateral oophorectomy procedures in patients over 40 years old with endometriosis

Objectives: To evaluate the rates of pain and mass recurrence of the patients over 40 years old with endometriosis who underwent ovarian cystectomy or uni/bilateral oophorectomy. Material and methods: A retrospective study was conducted with 98 patients undergoing laparoscopic surgery for endometriosis in a tertiary referral center between the time period July 2015 and July 2019. All the patients followed every 3 months and requested to fill the Visual Analogue Scale (VAS) for evaluation of pelvic pain and an ultrasound scan was performed. The inclusion criteria for this study were as follows, patients with ages over 40, with regular menstrual periods, and who denied hysterectomy and any postoperative hormonal medical treatments. Results: When the groups were compared in terms of age, body mass index, cyst diameter, CA-125 serum concentrations, preoperative and after surgical pelvic pain scores, mean follow up periods, postoperative hospital stay. However, each of the mean numbers of gravidity and parity were significantly higher than bilateral salpingo-oophorectomy (BSO) groups compared to the other groups (p = 0.04 and p = 0.03, respectively). The laterality, the recurrence rates, and the type of recurrence did not have a significant effect in the group comparison. Conclusions: The ovarian tissue preserving procedures could be offered for the women over 40 years old suffering from endometriosis with no significant increase in pain symptom or mass recurrence rates considering beneficial effects of estrogen on cardiovascular system, vasomotor symptoms, and bone mineral density