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Prediction of Gain Expansion and Intermodulation Performance of Nonlinear Amplifiers
Muhammad Taher Abuelma'atti 한국전자통신연구원 2007 ETRI Journal Vol.29 No.1
A mathematical model for the input-output characteristic of an amplifier exhibiting gain expansion and weak and strong nonlinearities is presented. The model, basically a Fourier-series function, can yield closedform series expressions for the amplitudes of the output components resulting from multisinusoidal input signals to the amplifier. The special case of an equal-amplitude two-tone input signal is considered in detail. The results show that unless the input signal can drive the amplifier into its nonlinear region, no gain expansion or minimum intermodulation performance can be achieved. For sufficiently large input amplitudes that can drive the amplifier into its nonlinear region, gain expansion and minimum intermodulation performance can be achieved. The input amplitudes at which these phenomena are observed are strongly dependent on the amplifier characteristics.
Muhammad Taher,Amnani Aminuddin,Deny Susanti,Nurul Iman Aminudin,Shamsul On,Farediah Ahmad,Hanisuhana Hamidon 한국생약학회 2016 Natural Product Sciences Vol.22 No.2
This paper reports in vitro cytotoxic, anti-inflammatory and adipocyte diffentiation with adipogenic effects of coumarins inophyllum D (1) and calanone (2), and a chromanone carboxylic acid namely isocordato-oblongic acid (3) isolated from Calophyllum symingtonianum as well as a biflavonoid morelloflavone (4) isolated from Garcinia prainiana on MCF-7 breast adenocarcinoma RAW 264.7 macrophages and 3T3-L1 preadipocytes cells, respectively. The cytotoxicity study on MCF-7 cell was conducted by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Meanwhile, the study of anti-inflammatory effects in RAW 264.7 macrophages and adipogenic effects on 3T3-L1 pre-adipocytes were conducted through nitrite determination assay and induction of adipocyte differentiation, respectively. In the cytotoxicity study, inophyllum D (1) was the only compounds that exhibited significant cytotoxic effect against MCF-7 cell with IC50 of 84 ?g/mL. Further, all by inhibiting the compounds have shown anti-inflammatory effects in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages of nitrite concentration with production. In addition, the compounds also exhibited adipogenic effects on 3T3-L1 pre-adipocytes by stimulating lipid formation. Thus, this study may provide significant input in discovery of the potential effects cytotoxic, anti-inflammatory and adipogenic agents.
Muhammad Taher,Putri Nur Hidayah Al-Zikri,Deny Susanti,Solachuddin Jauhari Arief Ichwan,Mohamad Fazlin Rezali 한국생약학회 2016 Natural Product Sciences Vol.22 No.4
Plant-derived triterpenoids commonly possesses biological properties such as anti-inflammatory, anti-microbial, anti-viral and anti-cancer. Luvunga scandens is one of the plant that produced triterpenoids. The aims of the study was to analyze cell cycle profile and to determine the expression of p53 unregulated modulator of apoptosis (PUMA), caspase-8 and caspase-9 genes at mRNA level in MCF-7 cell line treated with two triterpenoids, flindissol (1) and 3-oxotirucalla-7,24-dien-21-oic-acid (2) isolated from L. scandens. The compounds were tested for cell cycle analysis using flow cytometer and mRNA expression level using quantitative RT-PCR. The number of MCF-7 cells population which distributed in Sub G1 phase after treated with compound 1 and 2 were 7.7 and 9.3% respectively. The evaluation of the expression of genes showed that both compounds exhibited high level of expression of PUMA, caspase-8 and caspase-9 as normalized to b-actin via activation of those genes. In summary, the isolated compounds of L. scandens plant showed promising anticancer properties in MCF-7 cell lines.
Evaluation of Various Heuristics Techniques for Home Energy Management Using Smart Grid
Taher M. Ghazal,Shahan Yamin Siddiqui,Muhammad Ubaidullah,Hafiz Muhammad Usama,Sidra Khan,Muhammad Adnan Khan 한국차세대컴퓨팅학회 2022 한국차세대컴퓨팅학회 학술대회 Vol.2022 No.10
Electric energy is the basic need for human survival on this earth as these needs increase with the rapid increase in population. It’s become a challenge to manage home energy with the current situation. Smart grid provided different techniques to overcome these challenges to meet the need. This paper presents the result of the different optimization techniques that give the best performance in reducing cost, PAR, and user discomfort. Based on results the best result techniques are also combined to make a hybrid model for more accuracy. This paper not only describes optimization techniques but also the limitations and features of these techniques.
A New Voltage(Current)-Controlled Current-Feedback Operational-Amplifier Based Mulivibrator
Muhammad Taher Abuelma’atti,Zainualbideen Jamal Khalifa 대한전자공학회 2015 ITC-CSCC :International Technical Conference on Ci Vol.2015 No.6
In this paper a simple multivibrator circuit is proposed. The circuit uses two current-feedback operational amplifier. The duty cycle of the output rectangular wave can be controlled by adjusting a control voltage. The duty cycle can also be controlled by adjusting a control current instead of the control voltage.
Cloud Security Issues Detection Using Fuzzy Logic
Taher M. Ghazal,Shahan Yamin Siddiqui,Muhammad Ubaidullah,Hafiz Muhammad Usama,Ali Younas,Atif Ali 한국차세대컴퓨팅학회 2022 한국차세대컴퓨팅학회 학술대회 Vol.2022 No.10
Cloud computing is computing that provides, storage, databases, networking, intelligence, software, and analytics over the internet. Cloud services are delivered remotely and almost always from an offsite data center. Cloud services manage a better computing infrastructure efficiently. This study presents security issues & challenges in cloud computing and tries to find out the possible solution for some of the problems. It also discusses some solutions that deal with cloud computing-related to its privacy and security challenges. The proposed Intelligent Cloud Security Issues Detection using Multilayer Mamdani Fuzzy Inference System (ICSID-ML-MFIS) Expert System, can classify the different types of threats. The Expert System has eight input variables at layer-I, three input variables at layers-II, three input variables at layers-III, and six input variables at layers-IV. At layer-I input variables are threat-to-software, Traffic Monitoring, Networking Threat, Resource Availability, Platform availability, Trusted-Service-Availability, Device Availability, and Network Availability that detects output condition of threats to be affected or Not-Affected. At layer-II input variables are Detect SAAS Threats, Detect PAAS Threat, and Detect IAAS Threats, which determine the output condition as Yes or No. At layer-III input variables are Monitoring, Gaining, and managing which determine the output condition as cloud security type DCST. At layer-IV input variables are security incident response (SR), privilege identity management, locate current security problem (SP), super user account, a factor leading to inability to control traffic, and locate social engineering attacks. At last output, the layer consists of eight output types to detect the cloud security issues such as lack of visibility of data, theft of data, inability to control data, hijacking, system vulnerability, social engineering attacks, data breaches, and no-security issues. The proposed model based on Fuzzy reached 91.5% of true positive cases.
Data Mining Techniques : More Accurate Classified Algorithm For Cardiopulmonary Diseases Prediction
Taher M. Ghazal,Syed Hakim Masood,Atif Ali,Muhammad Usama Nazir 한국차세대컴퓨팅학회 2022 한국차세대컴퓨팅학회 학술대회 Vol.2022 No.10
Data mining techniques develop a more accurate classification algorithm for patients classified as either normotensive, prehypertensive, or hypertensive. Logistic Model Tree, NBTree, and Bagging were chosen as the three classification models with tenfold cross-validation (LMT). Over 24 hours, we collected ABP readings from 1161 patients. To analyze the data, data mining techniques were used and a tool called WEKA. The data was analyzed based on age, gender, wake-up blood pressure, medication, sleep-up blood pressure, and overall blood pressure. According to bagging results, 886 cases (76.3 percent) are correctly classified, with 270 cases classified as pre-hypertensive, 436 cases as Normotensive, and 180 cases as hypertensive. NBTree's results show that 882 (75.9%) of the 1161 instances are correctly classified. Pre-hypertensive patients make up 256, normotensive patients 442, and hypertensive patients 184. Of the 1161 instances, the LMT algorithm correctly classified 878 (75.6 percent). According to the results, 275 people are pre-hypertensive, 431 are normotensive, and 172 are hypertensive. According to our findings, bagging is the most accurate classifier for the 24 hour ABP Monitoring dataset we used. Bagging achieves less overfitting because it focuses on global accuracy. It stabilizes and improves the accuracy of unstable methods compared to single classifiers.
Mohammed Dahiru Ahmed,Muhammad Taher,Alhaji Hamusu Maimusa,Mohamad Fazlin Rezali,Mohammed Imad Al-deen Mustafa Mahmud 한국생약학회 2017 Natural Product Sciences Vol.23 No.1
An antimicrobial compound has been isolated from the leaves of Glochidion superbum. The compound was determined as methyl 3, 4, 5-trihydroxybenzoate (methyl gallate), based on ultraviolet (UV), infrared (IR), nuclear magnetic resonance (NMR) and mass spectroscopy (MS) analysis. The isolated compound exhibited potent antimicrobial activity against three clinical isolates of methicillin resistant Staphylococcus aureus (MRSA) by qualitative agar disc diffusion method and quantitative broth dilution method. Agar disc diffusion was done in a dose-dependent manner for each bacterial isolate at disc potencies of 25, 50, 100, and 150 ?g/disc. The zones of inhibition were on average equal to 12.27, 14.20, 15.43, and 24.17 mm respectively. The inhibition zones were compared with that of vancomycin disc at 30 ?g as a reference standard. The MIC and MBC values were 50 ?g/mL and 100 ?g/mL respectively. The results of anti MRSA activity were analyzed using one-way ANOVA with Turkey's HSD and Duncan test. In conclusion, methyl gallate which was isolated from G. superbum showed the inhibition activity against methicillin resistant S. aureus.
Sakil Mahmud,Yu Long,Muhammad Abu Taher,Han Hu,Ruoyu Zhang,Jin Zhu 한국섬유공학회 2020 Fibers and polymers Vol.21 No.7
Poly(butylene 2,5-furandicarboxylate) (PBF) derived from 2,5-furandicarboxylic acid (FDCA) is an emerging biobasedalipharomatic polyester that is expected to replace its fossil-based terephthalate and naphthate homologues. PBF holdsexcellent gas barrier properties, but its slow rate of crystallization might restrict wider applications. To improve the rate ofcrystalization, it was melt-blended with crystalline micro-cellulose (CMC) to prepare a composite through twin-screwextrusion. To ensure environmental friendly conditions, neither chemicals to modify fibers nor compatibilizers to improve thefiller/matrix interaction were used. Size exclusion chromatography (SEC), Fourier transform infrared (FTIR) spectroscopy,scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA) and Xraydiffraction (XRD) were used to characterize the composite. It was observed that a longer blending duration (cyclic mode)leads to a greater reduction in molecular weight (Mw) in the presence of CMC, which can be avoided by using a shorterblending duration (direct mode). The mechanical properties of the composite showed an increase in Young’s modulus byapproximately 23 % and 36 % with respect to reference PBF for the cyclic and direct mode respectively. It was furtherobserved that, although the elongation at break and tensile strength has decreased, it has improved gas barrier properties. Thermal analysis shows faster nucleation of PBF in the presence of CMC with a minor effect on its thermal degradation.