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Magnetic Resonance Brain Image Contrast Enhancement Using Histogram Equalization Techniques
Zahid Ullah,Su-Hyun Lee(이수현) 한국컴퓨터정보학회 2019 한국컴퓨터정보학회 학술발표논문집 Vol.27 No.1
Histogram equalization is extensively used for image contrast enhancement in various applications due to its effectiveness and its modest functions. In image research, image enhancement is one of the most significant and arduous technique. The image enhancement aim is to improve the visual appearance of an image. Different kinds of images such as satellite images, medical images, aerial images are affected from noise and poor contrast. So it is important to remove the noise and improve the contrast of the image. Therefore, for this purpose, we apply a median filter on MR image as the median filter remove the noise and preserve the edges effectively. After applying median filter on MR image we have used intensity transformation function on the filtered image to increase the contrast of the image. Than applied the histogram equalization (HE) technique on the filtered image. The simple histogram equalization technique over enhances the brightness of the image due to which the important information can be lost. Therefore, adaptive histogram equalization (AHE) and contrast limited histogram equalization (CLAHE) techniques are used to enhance the image without losing any information.
Saamia Zahid,Muhammad Ali Nasir,Saad Nauman,Mehmet Karahan,Yasir Nawab,H. M. Ali,Yasir Khalid,Muhammad Nabeel,Mudaser Ullah 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.1
In this study experimental investigation of interlaminar shear strength of glass fibre reinforced thermoplastic polyurethane (TPU) and epoxy based thermosets composites enhanced with multi walled carbon nanotubes (MWCNTs) is presented, and comparison is made between thermoplastic and thermosets composites. Suspension of MWCNTs in TPU and epoxy matrix was prepared using magnetic stirring and sonication technique. Both thermoplastic reinforced glass fibre and thermosets reinforced glass fibre composites were manufactured using hand layup technique. Carbon nanotubes were added in the concentrations of 0.1 %weight, 0.3 %weight and 0.5 %weight in both types of composites. Results showed that as the concentration of CNTs increases, the ILSS of the nanocomposites was also improved. With an addition of 0.5 % weight CNTs, there was improvement of 24.37 % in ILSS in epoxy based composites and 10.05 % enhancement in thermoplastic polyurethane reinforced glass fibre composites. The average ILSS obtained for thermoplastic polyurethane composites was less than that of epoxy composites. The TPU based composites also demonstrated inelastic deformations without any trace of brittle fracture. The pristine epoxy based composites on the other hand did show inelastic deformations followed by brittle fracture. Higher concentrations of MWCNTs led to an absence of brittle fracture during the tests, owing to the crack bridging effect of the CNTs.
Muhammad, Naik,Ullah, Zahid,Choi, Dong-Ho Springer-Verlag 2018 International Journal of Steel Structures Vol.18 No.1
<P>An effective numerical method is proposed for the three-dimensional nonlinear analysis of mooring cables using catenary theory. In this method, the mooring line is divided into finite number of catenary elements. In addition to self-weight, each catenary element is subjected to drag force due to steady ocean currents. The proposed procedure is validated by comparing the results with those of the shooting optimization and the finite element methods. Finally, a parametric study is conducted to study the effect of extensibility on the static response of mooring cables. The effects of fluid drag forces and cable extensibility on mooring cable tension, equilibrium configurations, and stressed lengths are illustrated for two- and three-dimensional mooring cable problems. From the numerical results, the method is found to be numerically stable, and it provides a more rational static response for mooring cables.</P>
Iqbal Muhammad Zahir,Ullah Akhtar,Aziz Umer,Asif Muhammad,Wabaidur Saikh Mohammad,Ansari Mohd Zahid 한국물리학회 2023 Current Applied Physics Vol.52 No.-
Hybrid supercapacitors (SCs) have acquired astonishing features and being recognized as prospective energy storage devices for energy applications. Herein this work, we describe the hydrothermal synthesis of cobalt sulfide and the polymerization of aniline to prepare polyaniline (PANI). Initially, each electrode was tested in three electrode setup in which the CoS/PANI composite showed high electrochemical performance compared to pristine sample. Furthermore, CoS/PANI was studied along with activated carbon (AC) to explore the hybrid SCs application of the prepared composite. In two electrode arrangement, the hybrid device has achieved a remarkable Qs of 123.6 C g-1 at 0.2 A g-1, energy 29.2 Wh kg-1 as well as high specific power 1275 W kg-1. The hybrid SCs also displayed a maximum capacity retain value of 86.4% after 5000 GCD cycles. These results show that the CoS/PANI can be utilized as a best electrode material for the contemporary energy storage devices.
Reactive oxygen species-mediated unfolded protein response pathways in preimplantation embryos
Ihsan Ali,Syed Zahid Ali Shah,Yi Jin,Zhong-Shu Li,Obaid Ullah,Nan-Zhu Fang 대한수의학회 2017 Journal of Veterinary Science Vol.18 No.1
Excessive production of reactive oxygen species (ROS) and endoplasmic reticulum (ER) stress-mediated responses are critical to embryonic development in the challenging in vitro environment. ROS production increases during early embryonic development with the increase in protein requirements for cell survival and growth. The ER is a multifunctional cellular organelle responsible for protein folding, modification, and cellular homeostasis. ER stress is activated by a variety of factors including ROS. Such stress leads to activation of the adaptive unfolded protein response (UPR), which restores homeostasis. However, chronic stress can exceed the toleration level of the ER, resulting in cellular apoptosis. In this review, we briefly describe the generation and impact of ROS in preimplantation embryo development, the ROS-mediated activation mechanism of the UPR via the ER, and the subsequent activation of signaling pathways following ER stress in preimplantation embryos.
복원 모델 기반 이상 탐지를 위한 효율적인 데이터 전처리 방법
Jaeyong Kang,Hyunseok Lim,Mingyu Kim,Zahid Ullah,Jeonghwan Gwak 한국차세대컴퓨팅학회 2021 한국차세대컴퓨팅학회 학술대회 Vol.2021 No.05
최근 몇 년간 딥 오토 인코더 또는 UNet과 같은 딥러닝 모델이 이상 상황 탐지를 위한 재구성 기반 모델로 사용되었다. 이러한 재구성 기반 모델은 재구성 손실을 기반으로 비정상 지수를 측정한다. 그러나 재구성 기반 모델의 탐지 성능은 입력 데이터의 형식에 따라 크게 좌우되므로 데이터 전처리 과정은 재구성 기반 이상 탐지 모델의 탐지 성능을 향상하는 데 매우 중요한 요소이다. 따라서 본 연구에서는 이상 탐지를 위한 새로운 데이터 처리 방법을 제안한다. 우리가 제안한 데이터 전처리 과정에서는 우선 현재 프레임과 이전 프레임 간의 차이를 계산하여 새로운 이미지를 생성한다. 그런 다음 새로 구축된 이미지를 UNet 모델에 대한 입력 이미지로 사용한다. 그런 다음 원래 이미지와 UNet 모델을 통해 재구성된 이미지 간의 차이를 계산하여 이상 영역 위치를 탐지한다. 실험에서 우리가 제안한 데이터 전처리 방법과 기존의 다른 데이터 전처리 기법의 탐지 성능을 비교하였다. 실험 결과 우리가 제안한 데이터 처리 방법을 사용한 UNet 기반 이상 탐지 모델이 다른 데이터 전처리 방법을 사용한 모델보다 이상 영역을 더 잘 탐지할 수 있음을 보여준다.
ResUNet++ 기반 이미지 복원 기법을 사용한 이상 탐지 시스템
Jaeyong Kang,Hyunseok Lim,Dongwook Min,Zahid Ullah,Jeonghwan Gwak 한국차세대컴퓨팅학회 2021 한국차세대컴퓨팅학회 학술대회 Vol.2021 No.05
이상 감지는 비디오 프레임에서 정상 이벤트에서 벗어난 이상 영역의 위치를 찾아내거나 또는 주어진 이미지에 대한 이상 상황 분류 문제에 중점을 둔다. 최근에는 입력 영상과 재구성 영상의 차이를 계산하여 이상 영역을 탐지하기 위해 오토 인코더 또는 UNet과 같은 딥 러닝 모델을 사용하는 접근 방식이 많이 제안되었다. 이러한 접근 방식은 오토 인코더 또는 UNet과 같은 모델이 비정상적인 영역에 대해서는 재구성할 수 없다고 가정한다. 그러나 이러한 접근 방식은 자동 인코더 또는 UNet가 가지는 높은 일반화 성능으로 인해 이상 영역도 정상 영역과 마찬가지로 충분히 잘 재구성하여 차이가 두드러지지 않는 문제가 흔히 발생한다. 이러한 문제를 해결하기 위해 본 연구에서는 이미지 영역의 특정 부분들을 제거하고 제거한 부분들에 대해 인페인팅 기법을 적용해 다시 이미지를 재구성하는 고급 이상 탐지 방식을 채택하였다. 또한, UNet 모델을 좀 더 개선한 모델인 ResUNet++를 이상 탐지 네트워크로서 사용하였다. 본 연구의 실험에서는 이상 탐지 분야에서 자주 사용되는 데이터 셋 중 하나인 UCSD Ped2 데이터 셋을 사용하였다. 실험 결과 본 연구에서 제안한 ResUNet++를 사용한 모델이 이상 영역을 잘 감지할 수 있음을 확인하였다.
Multi-aging Effects on Vegetable Based Oils for Transformer Insulation in HV Systems
Khan Irfanullah,Abid Muhammad Ahtasham,Ullah Kaleem,Ullah Zahid,Haider Aun,Ahmad Farhan Ammar,Zia Zain,Ali Sahibzada Muhammad 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.5
Liquid insulation media is used for insulation and cooling purpose inside the transformer. Currently, transformers are using petroleum based mineral oil, which poses a serious hazardous environmental impact, since the mineral oil is non-renewable and non-biodegradable. Although, the increased cost and depleting nature of mineral oil cause an emergent need to use suitable alternatives to mineral oils that are biodegradable and environmentally friendly. In response to this resource issue, various vegetable oils, namely Sunfl ower oil, Soya bean oil, and a blend of Sunfl ower and Olive (BSO) oil are suitable alternatives for transformer insulation in high voltage systems. The afore-mentioned vegetable oils are subjected to multi-aging and comparative analysis is performed with mineral oil. Further, the dielectric and thermal properties of vegetable oils are tested before and after aging. Fourier Transform Infrared spectroscopy, water content, breakdown voltage, viscosity, fl ash point, tan delta, and pour point tests are performed on vegetable oils before and after aging. Finally, a comparative analysis of vegetable oils with mineral oil is provided to prove the effi cacy of the proposed vegetable oils. The BSO oil resulted in higher breakdown strength and good thermal behavior when subjected to the abovementioned various diagnostic measurement tests in comparison to other oils