Image based visual servoing using bitangent points applied to planar shape alignment

We present visual servoing strategies based on bitangents for aligning planar shapes. In order to acquire bitangents we use convex-hull of a curve. Bitangent points are employed in the construction of a feature vector to be used in visual control. Experimental results obtained on a 7 DOF Mitsubishi PA10 robot, verifies the proposed method

Positioning and trajectory following tasks in microsystems using model free visual servoing

In this paper, we explore model free visual servoing algorithms by experimentally evaluating their performances for various tasks performed on a microassembly workstation developed in our lab. Model free or so called uncalibrated visual servoing does not need the system calibration (microscope-camera-micromanipulator) and the model of the observed scene. It is robust to parameter changes and disturbances. We tested its performance in point-to-point positioning and various trajectory following tasks. Experimental results validate the utility of model free visual servoing in microassembly tasks

Web and Java based architecture for laboratory experiments

Thesis (Master)--Izmir Institute of Technology, Computer Engineering, Izmir, 2003Includes bibliographical references (leaves: 54-55)Text in English; Abstract: Turkish and Englishix, 55 leavesDevelopments in the communication technologies area have increased the popularity of usage of communication channels for the education activities.Being one of these communication channels, Internet, has become an inevitable component for theoretical education.Internet has brought together instructor and student without any geographical constraint.But having different requirements and difficulties during the satisfaction of these requirements are the common drawbacks for the widespread usage of Internet for laboratory educations.In this thesis, methodologies, which can be used in remote laboratory systems, have been discussed. Requirements have been scrutinized and refined.Remote laboratory architecture for IYTE has been proposed according to these requirements.Analysis of software that can be developed on the proposed architecture has been made

Free Vibration Behavior of a Gradient Elastic Beam with Varying Cross Section

Based on strain gradient elasticity theory, a finite element procedure is proposed for computation of natural frequencies for the microbeams of constant width and linear varying depth. Weak form formulation of the equation of motion is obtained first as in common classical finite element procedure in terms of various kinds of boundary conditions. Gradient elastic shape functions are used for interpolating deflection inside a finite element. Stiffness and mass matrices are then calculated to solve the microbeam eigen value problem. A solution for natural frequencies is obtained using characteristic equation of microbeam in gradient elasticity. The results are given in a series of figures and compared with their classical counterparts. The effect of various slope values on the natural frequencies are examined in some numerical examples. Comparison with the classical elasticity theory is also performed to verify the present study

Gasoline pricing, taxation and asymmetry: The case of Turkey

This study analyzes the role of tax policy in gasoline prices in Turkey by utilizing time series techniques. It provides and compares empirical results by using daily gasoline prices between January 2005 and July 2012, with and without the effect of taxation. Our results, based on the standard asymmetric error-correction model, indicate no evidence of asymmetry in retail gasoline prices, which implies that the government does not benefit from the adjustment of gasoline prices through taxation. However, one can miss the big picture in gasoline pricing by concentrating only on the short term price adjustment dynamics via error-correction models. Therefore, we analyzed the long-run relationships between crude oil and gasoline prices with and without taxes. The results indicate that Turkish government succeeded at implicitly imposing an exceptionally high tax burden on gasoline (about 70%) over the longer term by adjusting non-salient excise tax amounts on gasoline and benefited from the resultant tax revenues as means of public finance

Lip segmentation using adaptive color space training

In audio-visual speech recognition (AVSR), it is beneficial to use lip boundary information in addition to texture-dependent features. In this paper, we propose an automatic lip segmentation method that can be used in AVSR systems. The algorithm consists of the following steps: face detection, lip corners extraction, adaptive color space training for lip and non-lip regions using Gaussian mixture models (GMMs), and curve evolution using level-set formulation based on region and image gradients fields. Region-based fields are obtained using adapted GMM likelihoods. We have tested the proposed algorithm on a database (SU-TAV) of 100 facial images and obtained objective performance results by comparing automatic lip segmentations with hand-marked ground truth segmentations. Experimental results are promising and much work has to be done to improve the robustness of the proposed method

İki noktada teğetler kullanarak görüntü tabanlı görsel geri beslemeli kontrol ile düzlemsel şekil hizalama

Bu bildiride, düzlemsel şekilleri hizalamak için iki noktada teğetlerden (bitangent) faydalanan görsel geri beslemeli kontrol stratejileri sunulmuştur. Bitangentları elde etmek ic¸in bir eğrinin dışbükey zarfından (convex-hull) yararlanılmıştır. İmge nitelik vektörü bitangent noktalarından oluşturularak görsel kontrolde kullanılmıştır. 7 serbestlik dereceli Mitsubishi PA10 robotu üzerinde gerçekleştirilen deneyler önerilen metodun geçerliliğini göstermiştir

Model-based vs. model-free visual servoing: A Performance evaluation in microsystems

In this paper, model-based and model-free image based visual servoing (VS) approaches are implemented on a microassembly workstation, and their regulation and tracking performances are evaluated. A precise image based VS relies on computation of the image jacobian. In the model-based visual servoing, the image Jacobian is computed via calibrating the optical system. Precisely calibrated model based VS promises better positioning and tracking performance than the model-free approach. However, in the model-free approach, optical system calibration is not required due to the dynamic Jacobian estimation, thus it has the advantage of adapting to the different operating modes

İneklerde geçiş döneminde anti-müllerian hormon, metabolik profil ve mineral düzeylerinin buzağılama – gebelik aralığına etkisi

The transition period in dairy cows is generally accepted as the period covering 3 weeks before calving and 3 weeks after calving. The aim of the study was to compare the profiles of β-hydroxybutyrate, calcium, magnesium, phosphorus, total cholesterol, total protein, triacylglycerol, free glycerol, serum lipid and serum protein with Anti-Mullerian Hormone (AMH) in dairy cows in the transition period, and to determine whether AMH to examine whether it can be used as a marker in the next insemination period. The cows whose blood samples were taken were followed up and it was determined that they became pregnant at the insemination and the study was terminated. According to the results obtained; It was determined that BHB and free glycerol, which are important markers of negative energy balance (NEB), have an effect on AMH concentration. However, it was determined that the concentration of magnesium and the ratio of cholesterol ester in serum total fat did not change much during the transition period. Our results suggest that AMH is a good biomarker of decreased follicular activity due to NEB in the transition period and that AMH can be used for herd weeding in reinsemination.Sütçü ineklerde geçiş dönemi genel kabul ile buzağılamadan önceki 3 hafta ile buzağılamadan sonraki 3 haftatı kapsayan süreçtir. Bu çalışmanın amacı geçiş dönemindeki sütçü ineklerde negaif eneji dengesinden (NED) dolayı değişen β-hidroksibütirat, kalsiyum, magnezyum, fosfor, total kolesterol, total protein, triaçilgliserol, serbest gliserol, serum lipid ve serum protein profillerinin Anti-Müllerian Hormon (AMH) ile karşılaştırılarak AMH’nin bir sonraki tohumlama döneminde belirteç olarak kullanılıp lullanılmayacağını incelemektir. Kan örnekleri alınan inekler daha sonra takip edilerek kaçıncı tohumlamada gebe kaldıkları tespit edildi ve çalışma sonlandırıldı. Santrifüj edilerek serumları toplanan kanlar analiz edildi. Elde edilen sonuçlara göre; NED’in önemli belirteçlerinden BHB’nin ve serbest gliserolün AMH konsantrasyonu üzerine etkisi olduğu saptandı. Bununla birlikte, magnezyumun konsantrasyonunun ve serum toplam yağı içerisindeki kolesterol esteri oranının geçiş döneminde fazla değişmediği tespit edildi. Sonuçlarımız AMH’nin geçiş döneminde NED’den dolayı azalan folliküler aktivitenin iyi bir biyobelirteci olduğunu ve tekrar tohumlamada AMH’nin sürü ayıklama için kullanılabileceğini göstermektedir