Gynecologic pathologies in our appendectomy series and literature review

Omer Engin,Bulent Calik,Mehmet Yildirim,Ali Coskun,Gulnihal Ay Coskun 대한외과학회 2011 Annals of Surgical Treatment and Research(ASRT) Vol.80 No.4

Purpose: Appendectomy applied from the diagnosis of acute appendicitis is one the most common operations in surgery. The rates of negative appendectomy are still high. The rates of negative appendectomy in males and females differ and are higher in females. In our study, these differences, particularly in females, were studied and possible solutions were discussed. Methods: Between October 2002 and October 2009, among women receiving urgent appendectomies, those whose primary cause was gynecological pathology were studied retrospectively. All our women subjects were examined by preoperative gynecologists. After gynecological consultation, the patients were evaluated by a general surgeon due to lack of urgent ultrasonography, computed tomography (CT) and diagnostic laparoscopy and the patient received appendectomy due to acute appendicitis. Results: In our series of 1,969 appendectomies, the rate of female/male is 811/1,158. It was determined that the primary cause in 47 (47/811; 5.8%) women with applied appendectomy was gynecological pathology. As a gynecological pathology, it was observed that the most common cause was ovarian cyst ruptures at a rate of 72.3%. The negative appendectomy rate in males was found to be 14.94% (173/1,158), and in females it was 22.56% (183/811). The difference between them is significant (P < 0.01). Of these women, 5.8% were gynecologically-induced and 16.76% were unrelated to gynecological causes. Conclusion: We believe that gynecological consultation before appendectomy in women is necessary, but not sufficient. It is also important that at least one of the facilities, such as us, CT, magnetic resonance imaging, and diagnostic laparoscopy should be available in surgical use for the diagnosis of negative appendicitis.

Unclassified Mucinous Renal Cell Carcinoma: A Rare Histopathological Entity

Omer A Raheem,Elana Godebu,Seth A. Cohen,Ahmed Shabaik,J. Kellogg Parsons 대한비뇨의학회 2014 Investigative and Clinical Urology Vol.55 No.10

Renal cell carcinoma (RCC) with mucin production is extremely rare. We present thecase of a previously healthy 76-year-old woman who underwent a robotic-assisted laparoscopicright nephrectomy for a 5-cm heterogeneously enhancing right renal mass. Pathology revealed mucin-producing epithelial RCC. We discuss the presentation andpathological features of this case and comment on its definitive treatment.

Consistent dynamic model identification of the Stäubli RX-160 industrial robot using convex optimization method

Omer Faruk Argin,Zeki Yagiz Bayraktaroglu 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.5

Dynamic models of robot manipulators with standard dynamic parameters are required for simulations, model-based controller design and external force estimation. The aim of this work is to identify the complete dynamic model of the 6-axis Stäubli RX-160 industrial robot. A convex optimization-based method is used for parameter identification. Consistent model parameters are obtained as the result of the optimization procedure subject to physical constraints. Low-speed behavior of the robot being dominated by joint friction, the dynamic model includes an algebraic friction model consisting of the Coulomb and viscous friction components along with the Stribeck effect. The coupled mechanical structure of the 5th and 6th joints, and elasticity due to the presence of balancing springs are also represented in the proposed dynamic model. The ordinary least square error method is used for the performance evaluation of the convex optimization-based method. Estimated parameters from both methods are experimentally verified over identification and test trajectories. The identified model is finally used as a basis in the estimation of external forces acting on the robot’s end-effector. The proposed sensor-less model-based approach for the estimation of external forces constitutes an alternative mean of experimental validation. Comparison of computed external forces with measured ones by an F/T transducer shows that the dynamic model obtained with the proposed method provides an accurate estimation.

Effect of Autoclave Curing on the Microstructure of Blended Cement Mixture Incorporating Ground Dune Sand and Ground Granulated Blast Furnace Slag

Omer Abdalla Alawad,Abdulrahman Alhozaimy,Mohd Saleh Jaafar,Farah Nora Abdul Aziz,Abdulaziz Al-Negheimish 한국콘크리트학회 2015 International Journal of Concrete Structures and M Vol.9 No.3

Investigating the microstructure of hardened cement mixtures with the aid of advanced technology will help the concrete industry to develop appropriate binders for durable building materials. In this paper, morphological, mineralogical and thermogravimetric analyses of autoclave cured mixtures incorporating ground dune sand and ground granulated blast furnace slag as partial cementing materials were investigated. The microstructure analyses of hydrated products were conducted using scanning electron microscopy (SEM), energy dispersive X ray spectroscopy (EDX), differential thermal analysis (DTA), thermo graphic analysis (TGA) and X ray diffraction (XRD). The SEM and EDX results demonstrated the formation of thin plate like calcium silicate hydrate plates and a compacted microstructure. The DTA and TGA analyses revealed that the calcium hydroxide generated from the hydration binder materials was consumed during the secondary pozzolanic reaction. Residual crystalline silica was observed from the XRD analysis of all of the blended mixtures, indicating the presence of excess silica. A good correlation was observed between the compressive strength of the blended mixtures and the CaO/SiO₂ ratio of the binder materials.

Augmentation of Fractional-Order PI Controller with Nonlinear Error-Modulator for Enhancing Robustness of DC-DC Boost Converters

Omer Saleem,Mohsin Rizwan,Ahmad Khizar,Muaaz Ahmad 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.4

This paper presents a robust-optimal control strategy to improve the output-voltage error-tracking and control capability of aDC-DC boost converter. The proposed strategy employs an optimized Fractional-order Proportional-Integral (FoPI) controllerthat serves to eliminate oscillations, overshoots, undershoots and steady-state fluctuations. In order to significantly improve theerror convergence-rate during a transient response, the FoPI controller is augmented with a pre-stage nonlinear error-modulator. The modulator combines the variations in the error and error-derivative via the signed-distance method. Then it feeds theaggregated-signal to a smooth sigmoidal control surface constituting an optimized hyperbolic secant function. The error-derivative isevaluated by measuring the output-capacitor current in order to compensate the hysteresis effect rendered by the parasiticimpedances. The resulting modulated-signal is fed to the FoPI controller. The fixed controller parameters are meta-heuristicallyselected via a Particle-Swarm-Optimization (PSO) algorithm. The proposed control scheme exhibits rapid transits with improveddamping in its response which aids in efficiently rejecting external disturbances such as load-transients and input-fluctuations. The superior robustness and time-optimality of the proposed control strategy is validated via experimental results.

A numerical parametric study on hydrofoil interaction in tandem

Omer Kemal Kinaci 대한조선학회 2015 International Journal of Naval Architecture and Oc Vol.7 No.1

Understanding the effects of the parameters affecting the interaction of tandem hydrofoil system is a crucial subject in order to fully comprehend the aero/hydrodynamics of any vehicle moving inside a fluid. This study covers a parametric study on tandem hydrofoil interaction in both potential and viscous fluids using iterative Boundary Element Method (BEM) and RANSE. BEM allows a quick estimation of the flow around bodies and may be used for practical purposes to assess the interaction inside the fluid. The produced results are verified by conformal mapping and Finite Volume Method (FVM). RANSE is used for viscous flow conditions to assess the effects of viscosity compared to the inviscid solutions proposed by BEM. Six different parameters are investigated and they are the effects of distance, thickness, angle of attack, chord length, aspect ratio and tapered wings. A generalized 2-D code is developed implementing the iterative procedure and is adapted to generate results. Effects of free surface and cavitation are ignored. It is believed that the present work will provide insight into the parametric interference between hydrofoils inside the fluid.

Dielectric and thermal properties of Na2O-CaO-SiO2- MgO-Al2O3-TiO2 glass-ceramic

Omer Kaygili,Fahrettin Yakuphanoglu,Cengiz Tatar 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.8

The Na2O-CaO-SiO2-MgO-Al2O3-TiO2 (NCSMAT) glass-ceramic having the composition of 49 Na2O, 19 CaO, 31 SiO2,0.25 MgO, 0.50 Al2O3 and 0.25 TiO2 (wt.%) was prepared by conventional method. The crystal structure, phase composition,microstructural, chemical, thermal and dielectric properties of the glass-ceramic were investigated. Using the X-ray diffraction(XRD) results, biphasic structure of the glass-ceramic sample was detected, the crystallite size was found to be 13.21 nm forNa4CaSi3O9 phase and 11.02 nm for Na8Al4Si4O18 phase, and the crystallinity percent was calculated to be 86.74 %. Scanningelectron microscope (SEM) observations show that the NCSMAT glass-ceramic has the fine-grained particle distribution withthe smaller particles than 1 µm. The stretching modes of Si-O-Si bound were detected from Fourier transform infrared (FTIR)spectrum. The NCSMAT glass-ceramic is thermally stable from room temperature to 1173 K and the mass loss of the samplein this range is 1.05%. The density was calculated to be 2,751 kg m−3. The relative permittivity at 1 kHz was found to be 85.35. The alternating current conductivity increases with increasing frequency and obeys the universal power law.

Sensitivity of WRF Model"s Physical Parameterizations on Surface Temperature Forecast in Sudan

Omer Khalid Hilal,Kim Sang Il 한국대기환경학회 2018 한국대기환경학회 학술대회논문집 Vol.2018 No.10

Robust Face Recognition under Limited Training Sample Scenario using Linear Representation

( Omer Iqbal ),( Waqas Jadoon ),( Zia Ur Rehman ),( Fiaz Gul Khan ),( Babar Nazir ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.7

Recently, several studies have shown that linear representation based approaches are very effective and efficient for image classification. One of these linear-representation-based approaches is the Collaborative representation (CR) method. The existing algorithms based on CR have two major problems that degrade their classification performance. First problem arises due to the limited number of available training samples. The large variations, caused by illumintion and expression changes, among query and training samples leads to poor classification performance. Second problem occurs when an image is partially noised (contiguous occlusion), as some part of the given image become corrupt the classification performance also degrades. We aim to extend the collaborative representation framework under limited training samples face recognition problem. Our proposed solution will generate virtual samples and intra-class variations from training data to model the variations effectively between query and training samples. For robust classification, the image patches have been utilized to compute representation to address partial occlusion as it leads to more accurate classification results. The proposed method computes representation based on local regions in the images as opposed to CR, which computes representation based on global solution involving entire images. Furthermore, the proposed solution also integrates the locality structure into CR, using Euclidian distance between the query and training samples. Intuitively, if the query sample can be represented by selecting its nearest neighbours, lie on a same linear subspace then the resulting representation will be more discriminate and accurately classify the query sample. Hence our proposed framework model the limited sample face recognition problem into sufficient training samples problem using virtual samples and intra-class variations, generated from training samples that will result in improved classification accuracy as evident from experimental results. Moreover, it compute representation based on local image patches for robust classification and is expected to greatly increase the classification performance for face recognition task.

Skeletal Angle Pattern Based Human Activity Recognition using RGB-Depth Sensor

Omer Faruk Ince,박장식 제어로봇시스템학회 2018 제어로봇시스템학회 국내학술대회 논문집 Vol.2018 No.5