Channel Clustering and QoS Level Identification Scheme for Multi-Channel Cognitive Radio Networks

Ali, Amjad,Yaqoob, Ibrar,Ahmed, Ejaz,Imran, Muhammad,Kwak, Kyung Sup,Ahmad, Adnan,Hussain, Syed Asad,Ali, Zulfiqar IEEE 2018 IEEE communications magazine Vol.56 No.4

<P>The increasing popularity of wireless services and devices necessitates high bandwidth requirements; however, spectrum resources are not only limited but also heavily underutilized. Multiple license channels that support the same levels of QoS are desirable to resolve the problems posed by the scarcity and inefficient use of spectrum resources in multi-channel cognitive radio networks (MCRNs). One reason is that multimedia services and applications have distinct, stringent QoS requirements. However, due to a lack of coordination between primary and secondary users, identifying the QoS levels supported over available licensed channels has proven to be problematic and has yet to be attempted. This article presents a novel Bayesian non-parametric channel clustering scheme, which identifies the QoS levels supported over available license channels. The proposed scheme employs the infinite Gaussian mixture model and collapsed Gibbs sampler to identify the QoS levels from the feature space of the bit rate, packet delivery ratio, and packet delay variation of licensed channels. Moreover, the real measurements of wireless data traces and comparisons with baseline clustering schemes are used to evaluate the performance of the proposed scheme.</P>

Adjusting Water Absorption, Stimulus-Response and Adsorption Capacity for Toxic Heavy Metal Ions of Poly(acrylamide-co-potassium methacrylate) Hydrogel by Poly(ethylene glycol) Addition

Syed Wasim Ali,Munib Ahmed Shafique,Muhammad Arif Malik,Muhammad Saad,Syeda Rida Amber,Aatiqa Jabeen 한국고분자학회 2021 폴리머 Vol.45 No.6

Hydrogels, composed of poly(acrylamide-potassium methacrylate), cross-linked with N,N"-methylene bis-acrylamide, and having different proportions of poly(ethylene glycol) were synthesized by a free radical copolymerization technique. The effect of the cross-linkage and poly(ethylene glycol) contents on swelling in water, diffusion kinetics of water in the hydrogel matrix, stimuli response to pH, ionic strength of the external solution, and capacity for chromium(III) and uranyl ions from polluted water samples were evaluated. The results show that the swelling in water decreased. Still, the diffusion rate of water in the copolymer matrix increased with an increase in the cross-linkage and an increase in the poly(ethylene glycol) amount under the conditions of this study. Poly(ethylene glycol) addition provided another tool to adjust the swelling, diffusion kinetics, and adsorption characteristics of the hydrogel. For example, poly(ethylene glycol) addition made the hydrogel adsorb uranyl ions from polluted water.

Delayed diagnosis of a primary intraosseous squamous cell carcinoma: A case report

Ahmed Z. Abdelkarim,Ahmed M. Elzayat,Ali Z. Syed,Scott Lozanoff 대한영상치의학회 2019 Imaging Science in Dentistry Vol.49 No.1

Primary intraosseous squamous cell carcinoma is a rare malignant central jaw tumor derived from odontogenic epithelial remnants. Predominantly, it affects mandible, although both jaw bones may be involved. This report describes a 60-yearold man who was initially misdiagnosed with a periapical infection related to the right lower wisdom tooth. After four months, the patient presented to a private dental clinic with a massive swelling at the right side of the mandible. Panoramic radiographs and advanced imaging revealed a lesion with complete erosion of the right ramus, which extended to the orbital floor. A biopsy from the mandibular angle revealed large pleomorphic atypical squamous cells, which is the primary microscopic feature of a poorly differentiated squamous cell carcinoma.

Resilience Assessment Framework for an Urban Road Network Subjected to Disruptions

Syed Qasim Abbas Kazmi,Syed Ahsan Ali Naqvi,Etikaf Hussain,Shoaib Ahmed 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.12

This research paper introduces a novel framework for assessing the resilience of urban transport networks. Traditional approaches to quantify resilience primarily focus on evaluating resilience based on the accessibility and vulnerability of network links. However, this study proposes a different approach by considering the dynamic role of links within the overall network, including their ability to accommodate additional traffic demand from other links. To accomplish this, a comprehensive scanning network approach is implemented using an iterative traffic assignment performed. The framework is applied to the urban transport network of Karachi, Pakistan. The model incorporates parameters for calibrations derived from volume delay functions, specifically alpha and beta, which are obtained from actual traffic travel times during free-flow and peak hours. The accuracy of the model is validated by comparing observed traffic counts at various locations with the simulated traffic volumes, resulting in an average error of 9% and a standard deviation of 7.4%. The study’s findings reveal significant losses within the network and identify critical links that are particularly susceptible to disruptions. The analysis provides valuable insights into delays experienced by travellers and the additional distances travelled when specific links are closed. Furthermore, the framework enables the evaluation of the overall impacts of disruptions at the network level. The proposed methodology will allow traffic engineers and decision-makers to effectively plan rerouted through alternative links during disruptions.

Mild hydrocracking of 1-methyl naphthalene (1-MN) over alumina modified zeolite

박주일,Syed Ahmed Ali,Khalid Alhooshani,Nor Azizi,Jin Miyawaki,김태곤,이영진,김현석,윤성호,Isao Mochida 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.2

The catalytic activity and life of the NiMoS supported on alumina–USY zeolite (physical mixture of alumina and USY (NMAZ), USY zeolite coated with alumina (NMACZ-2)) were compared in the hydrocracking of 1-methyl naphthalene by a single run at the several reaction temperatures between 360 and 400 8C as well as repeated runs at 360 8C. The relative activity of NMAZ is slightly higher after 1 h at all reaction temperatures, but was lower after 2 h at reaction temperatures above 380 8C. The preference of NMACZ-2 became distinct and definite by further increasing the reaction time at all reaction temperatures. Too long reaction time, particularly at higher reaction temperature, decreased the yield of (alkyl)benzenes, indicating the significant progress of the successive reactions. Thus, the highest yield of alkyl(benzenes) of about 97% was obtained over NMACZ-2 after 4 h at 380–390 8C. This was much less than the yield of about 82% obtained over NMAZ after 4 h at 370 8C. Ten repeated runs at 360 8C for 6 h resulted in marked decrease of yield over NMAZ from 73% to 64%, while the decrease in yield over NMACZ-2 was only from about 80% to 78%. The decrease of catalytic activity appears to reflect the coke formation on the USY which occurs on the naked acidic site of the substrate, which are rather isolated from the NiMoS on alumina. In contrast, alumina-coated support keeps USY underneath the alumina, which carries NiMoS and acidic sites on the same surface. The acidity of surface alumina is moderated by the underneath USY. The adequate acidity of the neighboring NiMoS and high hydrogenation activity provide a good balance resulting in an excellent catalytic activity and life of NiMoS supported on alumina-coated USY zeolite.

Delayed diagnosis of a primary intraosseous squamous cell carcinoma: A case report

Abdelkarim, Ahmed Z.,Elzayat, Ahmed M.,Syed, Ali Z.,Lozanoff, Scott Korean Academy of Oral and Maxillofacial Radiology 2019 Imaging Science in Dentistry Vol.49 No.1

Primary intraosseous squamous cell carcinoma is a rare malignant central jaw tumor derived from odontogenic epithelial remnants. Predominantly, it affects mandible, although both jaw bones may be involved. This report describes a 60-year-old man who was initially misdiagnosed with a periapical infection related to the right lower wisdom tooth. After four months, the patient presented to a private dental clinic with a massive swelling at the right side of the mandible. Panoramic radiographs and advanced imaging revealed a lesion with complete erosion of the right ramus, which extended to the orbital floor. A biopsy from the mandibular angle revealed large pleomorphic atypical squamous cells, which is the primary microscopic feature of a poorly differentiated squamous cell carcinoma.

Elimination of solidification shrinkage defects in the casting of aluminum alloy

Rashid Ali,Muhammad Zafar,Tareq Manzoor,Woo-Young Kim,Muhammad Usman Rashid,Syed Zameer Abbas,Behzad Ahmed Zai,Muddassir Ali 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.5

In this study, the analysis is carried out to optimize in-gate position and size of riser for casting mold. The baseline size of riser for the casting of boat propeller is based on geometric modulus and thermal analysis. The riser size is analyzed with thermal-volumetric numerical calculations to predict critical fraction solid (CFS) time and temperature gradient in casting. Simulation predictions are compared with inspection results of actual castings and found good qualitative agreement. The riser reached CFS temperature well before the castings’ cross-sectional transition regions. In feeding the molten metal, the in-gate is placed where the section modulus of casting is higher. However, the tongue of sand at in-gate increases the local cooling rate, resulting in early solidification and blockage of feeding path. The increase in riser size and in-gate position results in elimination of shrinkage cavities. An optical microscopy of the casting critical region is carried out to investigate the effect of numerical measures on internal closed microporosity and microstructure morphology.

Fenugreek Induced Apoptosis in Breast Cancer MCF-7 Cells Mediated Independently by Fas Receptor Change

Alshatwi, Ali Abdullah,Shafi, Gowhar,Hasan, Tarique Noorul,Syed, Naveed Ahmed,Khoja, Kholoud Khalid Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.10

Trigonella foenum in graecum (Fenugreek) is a traditional herbal plant used to treat disorders like diabetes, high cholesterol, wounds, inflammation, gastrointestinal ailments, and it is believed to have anti-tumor properties, although the mechanisms for the activity remain to be elucidated. In this study, we prepared a methanol extract from Fenugreek whole plants and investigated the mechanism involved in its growth-inhibitory effect on MCF-7 human breast cancer cells. Apoptosis of MCF-7 cells was evidenced by investigating trypan blue exclusion, TUNEL and Caspase 3, 8, 9, p53, FADD, Bax and Bak by real-time PCR assays inducing activities, in the presence of FME at $65{\mu}g/mL$ for 24 and 48 hours. FME induced apoptosis was mediated by the death receptor pathway as demonstrated by the increased level of Fas receptor expression after FME treatment. However, such change was found to be absent in Caspase 3, 8, 9, p53, FADD, Bax and Bak, which was confirmed by a time-dependent and dose-dependent manner. In summary, these data demonstrate that at least 90% of FME induced apoptosis in breast cell is mediated by Fas receptor-independently of either FADD, Caspase 8 or 3, as well as p53 interdependently.

Ethernet‑Based Fault Diagnosis and Control in Smart Grid: A Stochastic Analysis via Markovian Model Checking

Riaz Uddin,Ali S. Alghamdi,Muhammad Hammad Uddin,Ahmed Bilal Awan,Syed Atif Naseem 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.6

The fault diagnosis and control through fault detection, isolation and supply restoration (FDIR) technique is the part of a commonly used distribution management system application in smart grid. When the fault occurs, it becomes essential to detect and isolate the faulty section of the distribution network at once and then restore back to its running condition through tie switches. The communication between IEDs is done through diferent communication mediums such as Ethernet, wireless, power line communication etc. Therefore, formal analysis of the FDIR mechanism is required with communication network (ideally Ethernet), which helps us to predict the behavior of FDIR response upon the occurrence of fault in terms of various important probabilities, reliability study and efciency (showing the system will work properly). In this regard, for the above said analyses, this article discusses (a) the development of the Markovian model of FDIR for distribution network of smart grid considering Tianjin Electric Power Network as case study with intelligent electronic devices (IEDs) using ideal communication medium (Ethernet); (b) utilized probabilistic model checker (PRISM tool) to predict the probabilities; (c) perform the reliability analyses and (d) study the efciency of FDIR behavior for future grid using logical properties. The detailed analysis and prediction (done for the fault occurrence scenario) mainly focus in determining the (1) the probability of switching failures of FDIR in smart grid; (2) the probability of isolating the defective switch from the system within limited time and (3) the probability of restoring the system automatically within the minimum possible interval.

Analysis and deep hydrodesulfurization reactivity of Saudi Arabian gas oils

김태곤,박주일,Syed Ahmed Ali,Khalid Alhooshani,Mohammed Al-Yami,윤성호,Isao Mochida 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.5

Gas oils obtained from Arabian Light (AL-GO), Arabian Medium (AM-GO) and Arabian Heavy (AH-GO)crude oils were subjected to detailed analysis in terms of reactive and refractory sulfur, nitrogen, as well as aromatic species. Deep hydrodesulfurization (HDS) of these gas oils over SiO2–Al2O3-supported CoMo and NiMo catalysts was studied using autoclave reactor either in one- or two-stage operations. AL-GO was easily and deeply desulfurized to 15 ppm over CoMo/Al2O3–SiO2 (catalyst X) at 340 8C and 5 MPa (H2) for 2 h. At the same conditions, AM-GO and AH-GO could be desulfurized to 70 and 78 ppm,respectively. Two-staged HDS, by combining CoMo and NiMo catalysts, in successive steps resulted in effective deep HDS. The replacement of hydrogen atmosphere after the first-stage (1 h) enhanced the AH-GO HDS during the second-stage (1 h) to 9 ppm. However, replacing the hydrogen in the secondstage with 5% H2S in hydrogen inhibited the HDS, resulting in product sulfur content of 15 ppm. Analysis of sulfur species indicate that significant fraction of reactive and refractory sulfur species were removed during the first-stage whereas the remaining refractory sulfur species were removed during the second-stage. Kinetic analysis indicates overwhelming influence of refractive sulfur species on the overall HDS. The results from this study show that two-stage scheme with optimum catalysts in series can be applied to overcome the difficulty to achieve deep HDS of AH-GO.