Three-Dimensional Extended Object Tracking and Shape Learning Using Gaussian Processes

In this study, we investigate the problem of tracking objects with unknown shapes using three-dimensional (3D) point cloud data. We propose a Gaussian process-based model to jointly estimate object kinematics, including position, orientation and velocities, together with the shape of the object for online and offline applications. We describe the unknown shape by a radial function in 3D, and induce a correlation structure via a Gaussian process. Furthermore, we propose an efficient algorithm to reduce the computational complexity of working with 3D data. This is accomplished by casting the tracking problem into projection planes which are attached to the object's local frame. The resulting algorithms can process 3D point cloud data and accomplish tracking of a dynamic object. Furthermore, they provide analytical expressions for the representation of the object shape in 3D, together with confidence intervals. The confidence intervals, which quantify the uncertainty in the shape estimate, can later be used for solving the gating and association problems inherent in object tracking. The performance of the methods is demonstrated both on simulated and real data. The results are compared with an existing random matrix model, which is commonly used for extended object tracking in the literature

Extended Target Tracking and Classification Using Neural Networks

Extended target/object tracking (ETT) problem involves tracking objects which potentially generate multiple measurements at a single sensor scan. State-of-the-art ETT algorithms can efficiently exploit the available information in these measurements such that they can track the dynamic behaviour of objects and learn their shapes simultaneously. Once the shape estimate of an object is formed, it can naturally be utilized by high-level tasks such as classification of the object type. In this work, we propose to use a naively deep neural network, which consists of one input, two hidden and one output layers, to classify dynamic objects regarding their shape estimates. The proposed method shows superior performance in comparison to a Bayesian classifier for simulation experiments

Exposure to Perchlorate in Lactating Women and Its Associations With Newborn Thyroid Stimulating Hormone

Background: Perchlorate, thiocyanate, and nitrate can block iodide transport at the sodium iodide symporter (NIS) and this can subsequently lead to decreased thyroid hormone production and hypothyroidism. NIS inhibitor exposure has been shown to reduce iodide uptake and thyroid hormone levels; therefore we hypothesized that maternal NIS inhibitor exposure will influence both maternal and newborn thyroid function.Methods: Spot urine samples were collected from 185 lactating mothers and evaluated for perchlorate, thiocyanate, and nitrate concentrations. Blood and colostrum samples were collected from the same participants in the first 48 h after delivery. Thyroid hormones and thyroid-related antibodies (TSH, fT3, fT4, anti-TPO, anti-Tg) were analyzed in maternal blood and perchlorate was analyzed in colostrum. Also, spot blood samples were collected from newborns (n = 185) between 48 and 72 postpartum hours for TSH measurement. Correlation analysis was performed to assess the effect of NIS inhibitors on thyroid hormone levels of lactating mothers and their newborns in their first 48 postpartum hours.Results: The medians of maternal urinary perchlorate (4.00 μg/g creatinine), maternal urinary thiocyanate (403 μg/g creatinine), and maternal urinary nitrate (49,117 μg/g creatinine) were determined. Higher concentrations of all three urinary NIS inhibitors (μg/g creatinine) at their 75th percentile levels were significantly correlated with newborn TSH (r = 0.21, p < 0.001). Median colostrum perchlorate level concentration of all 185 participants was 2.30 μg/L. Colostrum perchlorate was not significantly correlated with newborn TSH (p > 0.05); however, there was a significant correlation between colostrum perchlorate level and maternal TSH (r = 0.21, p < 0.01). Similarly, there was a significant positive association between colostrum perchlorate and maternal urinary creatinine adjusted perchlorate (r = 0.32, p < 0.001).Conclusion: NIS inhibitors are ubiquitous in lactating women in Turkey and are associated with increased TSH levels in newborns, thus signifying for the first time that co-exposure to maternal NIS inhibitors can have a negative effect on the newborn thyroid function

Bir insansız su üstü aracının navigasyonu ve denetimi.

In this study, navigation and control algorithms for unmanned sea surface vehicles are investigated. For this purpose, firstly the mathematical model of a sea surface vehicle with two propellers providing stable maneuvering capabilities is constructed considering Newton-Euler equations. The next phase is to design a suitable navigation algorithm which integrates the solutions of “Inertial Navigation System (INS)” and external aids such as “Global Navigation Satellite System (GNSS)” and magnetometer. At this step, different loosely coupled integration algorithms are developed, and their performances are compared. After that, a model boat is assembled with necessary electrical equipment and driving system as a test platform for the navigation implementations. The results of the navigation algorithm obtained by processing real data collected from the model boat are presented. Meanwhile, the corrected navigation solution is also utilized within a parallel independent study aiming to identify the real parameters of the mathematical model of the boat. Finally, the design of various autopilot algorithms is studied taking the improved mathematical model into account. LQR and “Feedback Linearization” based controllers are realized for this job. The results of the controllers are provided and compared.M.S. - Master of Scienc

A survey on tactical control algorithms for path tracking unmanned surface vehicles

In this study, a survey on control allocation algorithms in tactical level control for path tracking unmanned surface vehicles (USV) is conducted. The strategic goal in the path tracking problem is to assist navigation solution of an unmanned underwater vehicle (UUV). USV with the help of its onboard acoustic sensors, tracks UUV according to constant bearing guidance rule. The survey on tactical controllers comprises comparisons of tracking performances of USVs under proportional-integral-derivative, pole placement, feedback linearization and sliding mode controllers according to the strategic goal. The parameters of the controllers are tuned with a common elitist genetic algorithm optimization infrastructure. The disturbance rejection capabilities of the controllers are discussed through Monte Carlo simulations of USVs within various wave disturbances as well

Konstrüktif Ödevlerin Sistematik Geliştirilmesi Ve Bir Uygulama Örneği

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 1998Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 1998Konstrüksiyon esas itibarıyla yaratıcı olan, bilim ve deneyimlerden elde edilen bilgiler üzerine kurulan ve optimal bir çözümü amaçlayan bir uğraşıdır. Konstrüktif geliştirme prosesi bilimsel ve pratik açıdan incelenebilir. Konstrüktif geliştirme ile uğraşan bilim adamları daha çok soyut ve teorik kavramlar içeren Konstrüksiyon Bilimleri ile uğraşmaktadırlar. Daha basit ve anlaşılır ancak bilimsel tabana dayanmayan, bir çok konstrüktörün kolayına gelen pratik konstrüksiyon çalışmaları ise daha yaygın olarak yapılmaktadır. Bilimsel konstrüksiyonda tümdengelim tarzı çalışma yöntemi söz konusudur. Ayrıntılı ve geniş bir bazda yapılan çalışmada genel problem ele alınmakta ve metodik çalışma adımlarıyla birim probleme inilmektedir. Teknik sistemlerin geliştirilmesi ve üretilmesi süreci, aralarında sıkı ilişkiler olan usul geliştirme, konstrüktif geliştirme ve teknolojik geliştirme süreçlerinden oluşur. Pazardan doğrudan doğruya veya dolaylı olarak konstrüksiyon bürosuna gelen ürün fikri üzerine konstrüktif geliştirme süreci başlar. Konstrüksiyonun öğrenilebilir ve öğretilebilir bir teknik bilim veya teknik olması için bunu bir sistematik içine oturtma gereği vardır. Kuvvetli bilimsel bir alt yapı üzerine inşa edilecek konstrüksiyon tekniği mühendislik bilimlerindeki yeni hesap metotlarının ve bunların bilgisayar yardımı ile kullanılmasının yanında hızla diğer alanlara da yayılan sistem tekniği usul ve metotlarından yararlanılmasına olanak sağlamaktadır. Soyuttan somuta doğru ilerleyen konstrüktif geliştirme sürecinin çalışma kademelerine konstrüktif geliştirme sürecinin fazları denir. Bu fazlar, ödevin analizi ve kesinlik kazanması, tasarım ve şekillendirme adı altında açıklanmıştır. Yapılan çalışmaların sonucunda ödevi yerine getiren birden fazla çözüme ulaşılmaktadır. Her seçme işleminde iki önemli nokta vardır. Bunlar, hiç başarı şansı olmayanları elemek ve başarı şansı olanları aralarında belirli değerlendirme kriterlerine göre sıralamaktır. Son yıllarda üzerinde en çok durulan değerlendirme yöntemlerinden biri Fayda - Değer Analizidir. Benzer bir değerlendirme sistemi de VDI 2225 esaslan ile Alman Mühendisler Birliği tarafından duyurulan Teknik - Ekonomik Değerlendirme sistemidir. Çeşitli çözüm tipleri için tespit edilen değerlendirme tablolarının kritik bir incelemeye tabi tutulması ile her bir çözüm hali için değer düşüren hedef kriterlerinin ne olduğu Zayıf Nokta Analizi'ne dayanarak Değer Profili hazırlanıp tespit edilmektedir. Yukarıda da belirtilen açıklamalar ışığında bir ödevin sistematik olarak geliştirilmesi için gerekli çalışmalar Piezo Çakmak için tatbik edilmiş, ortaya çıkan farklı çözümler arasından en uygun olanı Fayda-Değer Analizi ve Teknik ve Ekonomik değerlendirmeler sonucunda tespit edilmiş, ayrıca her bir çözüm hali için değer düşüren hedef kriterleri, çözümlerin değer profilleri hazırlanarak tespit edilmiştir.Construction is an activity that is creative, based on knowledge gained from science and experience and oriented towards getting an optimal solution. The constructive development process can be analyzed from a scientific and a practical standpoint. Scientists who work on constructive development are involved in Constructions Sciences which are largely focused on theoretical and abstract concepts, Practical construction works which practicing constructors prefer are widespread, simpler and easier to understand but don't have a scientific basis. On scientific construction the work method used is based on the principle. On a detailed and comprehensive work the first step is to look at the general problem and to go down to the unit problem through certain methodological steps. The process of developing and producing technical systems consists of method development, constructive development and technological development. The constructive development process starts when a product idea reaches the construction office directly or indirectly from the market. In order for construction to be a technique or technical science that can be taught and learnt, it has to be systematic. A construction technique that is based on sound scientific knowledge will assist to the rapid acquisition and computer aided implementation of new calculation techniques in engineering. Moreover, it will provide a basis for making better use of the ways and means of that systems technique which is expanding rapidly. The different steps used in a constructive development process move from the abstract to the concrete and these are known as the phases. These phases are referred to task analysis and finalization, design and formation. At the and of the analyses, more then a single number of solutions fulfilling the same task are identified. Any selection, two points have to be considered: These are the elimination of the no-chance option and the ranking of those options with a chance of success according to certain evaluation criteria. In the recent years, one of the most prominent evaluation methods is the Benefit - Value Analysis. Another similar evaluation system is the Technical - Economical Evaluation system based on VDI 2225 and developed by German Engineers Association. Evaluation charts are prepared for different solution options, critically analyzed and a Value Profile is prepared by comparing the solution with target criteria by means of Weak Point Analyses. This study has applied the above mentioned steps of systematically developing a task to the case of Piezo Ignitor. Among the options identified the most suitable one has been assessed by Benefit - Value and Technical and Economic evaluations and target criteria that decrease value for each solution have been defined by means of the value profiles of the available options.Yüksek LisansM.Sc

3D Extended Object Tracking Using Recursive Gaussian Processes

In this study, we consider the challenging task of tracking dynamic 3D objects with unknown shapes by using sparse point cloud measurements gathered from the surface of the objects. We propose a Gaussian process based algorithm that is capable of tracking the dynamic behavior of the object and learn its shape in 3D simultaneously. Our solution does not require any parametric model assumption for the unknown shape. The shape of the objects is learned online via a Gaussian process. The proposed method can jointly estimate the position, orientation, and the shape of the object. The inference is performed by an extended Kalman filter which is suitable for online real-time applications. Lastly, we demonstrate the initial results of a promising approach, which aims at reducing the computational complexity

Variational Measurement Update for Extended Object Tracking Using Gaussian Processes

We present an alternative inference framework for the Gaussian process-based extended object tracking (GPEOT) models. The method provides an approximate solution to the Bayesian filtering problem in GPEOT by relying on a new measurement update, which we derive using variational Bayes techniques. The resulting algorithm effectively computes approximate posterior densities of the kinematic and the extent states. We conduct various experiments on simulated and real data and examine the performance compared with a reference method, which employs an extended Kalman filter for inference. The proposed algorithm significantly improves the accuracy of both the kinematic and the extent estimates and proves robust against model uncertainties

The Relationship Between Business Cycle and Energy Prices in Turkey

anemonRecently it is observed an increase in businesscycle in Turkey. One of the most important factors affecting these fluctuationsis energy prices. In this study, relations between business cycle and energyprices are investigated using analysis of cross correlation, causalityanalysis, impulse response analysis and VAR model for the period of 1998-Q3 and2017-Q2 in Turkey. In the study, quarterly time series are used for thevariables of real gross domestic product, coal, oil and electricity priceindex. As a result of the analysis; it is observed that fluctuations in coal, oil and electricity prices move in reverse direction with business cycle andthat there is a one-way causality relationship from the electricity price indexto business cycle. Furthermore, the largest share of the change that may occuron business cycle has been found to be the change in electricity prices.Sondönemlerde Türkiye’de konjonktürel dalgalanmaların sıklaştığı ve boyutununarttığı gözlemlenmektedir. Bu dalgalanmaları etkileyen en önemli unsurlardanbiri enerji fiyatlarıdır. Bu amaçla çalışmada, Türkiye’de 1998-Q3 ve 2017-Q2dönemi için konjonktür dalgalanmaları ile enerji fiyatları arasındaki ilişkiçapraz korelasyon, nedensellik analizi, etki-tepki analizi ve VAR modeliyardımıyla analiz edilmektedir. Çalışmada reel gayrisafi yurtiçi hasıla, kömür, petrol ve elektrik fiyat endeksi değişkenlerine ilişkin üç aylık zaman serilerikullanılmıştır. Yapılan analiz sonucunda; kömür, petrol ve elektrik fiyatlarındaki dalgalanmaların her birininkonjonktürel dalgalanmalar ile ters yönde hareket ettiği ve elektrik fiyatlarındakidalgalanmalardan konjonktürel dalgalanmalara doğru tek yönlü bir nedensellikilişkisinin olduğu gözlemlenmiştir. Ayrıca konjonktürel dalgalanmalar üzerindemeydana gelebilecek değişimi açıklamada en büyük paya elektrik fiyatlarındakideğişimin sebep olduğu bulgusuna ulaşılmıştır.45264