RLECN—A learning based dynamic threshold control of ECN

Shahzad,정은성,김형석 한국통신학회 2023 ICT Express Vol.9 No.6

Explicit congestion notification (ECN) enables the network routers to mark packets instead of dropping them. When the queue size reaches a certain threshold, the queued packets are marked to indicate predicted congestion. However, an optimal value of the ECN threshold is not defined. A pre-decided value is chosen either by estimation or by hit and trial and therefore, it does not generalize well under a wide range of network scenarios. We propose a reinforcement learning (RL)-based ECN mechanism that utilizes software-defined networks (SDN) to address this problem. Our solution enables the routers to keep a dynamic ECN threshold according to the current network conditions. SDN provides the network visibility and reach to train the RL model and to dynamically adjust the ECN threshold. We show through experimental results that our proposed model outperforms the current state of the art.

Highly sensitive electrochemical sensor based on environmentally friendly biomass-derived sulfur-doped graphene for cancer biomarker detection

Shahzad, F.,Zaidi, S.A.,Koo, C.M. Elsevier Sequoia 2017 Sensors and actuators. B, Chemical Vol.241 No.-

<P>Herein, we demonstrate a sulfur-doped reduced graphene oxide (SrGO) product fabricated using an ecofriendly biomass precursor 'lenthionine' through a high temperature doping process. The product is used for making a highly sensitive electrochemical sensor for detection of 8-hydroxy-2'-deoxyguanosine (8-OHdG) molecule, which is an important biomarker for oxidative stress, cardiovascular diseases, and cancers. The sulfur-doping amount was regulated and a maximum sulfur content of 2.28 atom% was achieved through controlling the precursor amount. Homogenous presence of large number of sulfur atoms in SrGO in the form of thiophenic (-C-S-C-) bond produced robust sensitivity (similar to 1 nM), very wide detection window (20-0.002 mu M), good selectivity, high stability and reproducibility, and excellent recoveries for the detection of 8-OHdG biomarker in optimized experimental conditions. The excellent electrochemical sensitivity of SrGO sensor is attributed to the strong electron-donating ability of sulfur that facilitates the electron transfer to the biomolecules in the electrochemical reactions. Thus, the proposed method endorses an excellent platform for the electrochemical detection of 8-OHdG with great ease and reliability. (C) 2016 Elsevier B.V. All rights reserved.</P>

Influence of Replacing Corn Grain by Enzose (Corn Dextrose) on Nutrient Utilization, Thyroid Hormones, Plasma Metabolites, and Weight Gain in Growing Lambs

Shahzad, M. Aasif,Nisa, M.,Sarwar, M. Asian Australasian Association of Animal Productio 2011 Animal Bioscience Vol.24 No.7

The study was conducted to evaluate enzose (corn dextrose), a corn milling byproduct, as substitute for corn grain as energy in growing lambs. Five iso-caloric and iso-nitrogenous diets were formulated. The control diet (E0) had no enzose whereas enzose replaced 20, 40, 60 and 80% corn grain in E20, E40, E60 and E80 diets on the basis of energy supply, respectively. Fifty growing lambs were divided into 5 groups, 10 animals in each, in a randomized complete block design. Nutrients (dry matter, crude protein, neutral detergent fiber and acid detergent fibre) intake and digestibilities increased with gradual replacement of corn grain by enzose. Lambs fed E80 diet also retained higher nitrogen (N) than those fed E0 diet. Plasma glucose, $T_3$ and $T_4$ increased while urea N decreased in lambs receiving higher enzose content. Maximum weight gain was recorded in lambs fed diets containing maximum concentration of E as a replacement for corn grains. A better feed conversion ratio was recorded in lambs fed E80 compared with those fed E0 diet. The study suggests that enzose can be used as an economical feed ingredient to replace corn grain upto 80%, without any adverse effects on growth performance of growing lambs.

Ti₃C₂T_x MXene core-shell spheres for ultrahigh removal of mercuric ions

Shahzad, Asif,Nawaz, Mohsin,Moztahida, Mokrema,Jang, Jiseon,Tahir, Khurram,Kim, Jiho,Lim, Youngsu,Vassiliadis, Vassilios S.,Woo, Seung Han,Lee, Dae Sung Elsevier 2019 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.368 No.-

<P><B>Abstract</B></P> <P>Two-dimensional (2-D) titanium carbide MXene core (Ti<SUB>3</SUB>C<SUB>2</SUB>T<SUB>x</SUB>) shell aerogel spheres (MX-SA) for mercuric ion removal were designed and fabricated with varying concentrations of Ti<SUB>3</SUB>C<SUB>2</SUB>T<SUB>x</SUB> MXene and sodium alginate (SA) using a facile method. Owing to their unique inside structures, high porosities, large specific surface areas, oxygenated functional groups of MXene nanosheets, and available active binding sites, the synthesized microspheres constitute a unique adsorbent for heavy metals removal in water. The MX-SA<SUB>4:20</SUB> spheres exhibit an exceptional adsorption capacity of 932.84 mg/g for Hg<SUP>2+</SUP>, which is among the highest value reported for adsorbents. The adsorbent exhibits high single- and multi-component removal efficiencies, with 100% efficiency for Hg<SUP>2+</SUP> and >90% efficiency for five heavy metal ions. The synthesized materials are highly efficient for Hg<SUP>2+</SUP> removal under extreme pH conditions (0.5–1.0 M HNO<SUB>3</SUB>) and have additional excellent reproducible properties. The micro-size and spherical shape of MX-SA<SUB>4:20</SUB> also allow it to be used in column-packed devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ti<SUB>3</SUB>C<SUB>2</SUB>T<SUB>x</SUB> nanosheets were synthesized using a low-toxicity etching agent (NH<SUB>4</SUB>F). </LI> <LI> Core-shell of MX-SA<SUB>4:20</SUB> spheres was capable of very effectively removing heavy metals. </LI> <LI> MX-SA<SUB>4:20</SUB> spheres exhibited exceptional Hg<SUP>2+</SUP> adsorption capacity of 932.84 mg g<SUP>−1</SUP>. </LI> <LI> MX-SA<SUB>4:20</SUB> performed excellently in extreme acidic conditions. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Fabrication of MX-SA<SUB>4:20</SUB> spheres through MXene-Alginate networking and their application in Hg<SUP>2+</SUP> uptake.</P> <P>[DISPLAY OMISSION]</P>

Impact of Social and Institutional Quality Capital on Total Factor Productivity and Economic Growth

Shahzad Saeed,유태환 경성대학교 산업개발연구소 2018 산업혁신연구 Vol.34 No.3

This study examines whether economic growth is affected by social and institutional quality capital directly or indirectly via total factor productivity (TFP). Based on the fifth-wave data of the World Values Survey conducted during 1995–2014 (2005–2009 for short-run analysis), we adopt a cross-sectional and pooled time series regression framework to investigate the role of social and institutional quality capital on economic growth and TFP changes for 12 high-income and 15 low- and middle-income countries (24 high-income and 25 low- and middle-income countries for the short-run), respectively. The research extrapolates that there are considerable differences in the strength of impact for social and institutional quality capital in the countries with different income levels over different time horizons. Specifically, social capital explicates a positive effect on economic growth only for high-income countries in the long-run. While having both direct and indirect effects, the institutional quality capital affects economic growth indirectly via TFP with a higher magnitude, except for low- and middle-income countries in the long-run, compared to the short-run with regard to other income groups.

Heterostructural TiO₂/Ti₃C₂T_x (MXene) for photocatalytic degradation of antiepileptic drug carbamazepine

Shahzad, Asif,Rasool, Kashif,Nawaz, Mohsin,Miran, Waheed,Jang, Jiseon,Moztahida, Mokrema,Mahmoud, Khaled A.,Lee, Dae Sung Elsevier 2018 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.349 No.-

<P><B>Abstract</B></P> <P>A simple hydrothermal treatment process was used for the fabrication of a Ti<SUB>3</SUB>C<SUB>2</SUB>T<SUB>x</SUB> (MXene) nanosheet-based hybrid photocatalyst. The chemical composition of the MXene and its derivatives (nanosize {0 0 1} facets of TiO<SUB>2</SUB> in Ti<SUB>3</SUB>C<SUB>2</SUB>T<SUB>x</SUB> (001-T/MX)), as well as the structural properties and morphology of the as-prepared photocatalyst, were well characterised. The heterostructure of the as-prepared photocatalyst was obtained by controlled oxidation action via the Schottky junction formed between TiO<SUB>2</SUB>-MXene interfaces. The adsorption/photocatalytic degradation abilities of the pristine MXene and the as-synthesised 001-T/MX nanocomposite for carbamazepine (CBZ) were investigated. The determined <I>K<SUB>app</SUB> </I> value of CBZ under ultraviolet light was 0.0304 min<SUP>−1</SUP>, higher than that under natural solar light, and the degradation capacity was strongly controlled under acidic conditions (pH 3.0–5.0). During the photocatalytic degradation, <SUP> </SUP>OH and <SUP> </SUP>O<SUB>2</SUB> attacked the CBZ molecule; detailed degradation pathways were proposed accordingly. The novel heterojunction 001-T/MX exhibited excellent applicability for CBZ decomposition.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A simple hydrothermal process is used for the fabrication of Ti<SUB>3</SUB>C<SUB>2</SUB>T<SUB>x</SUB> (MXene) nanosheets. </LI> <LI> Ti<SUB>3</SUB>C<SUB>2</SUB>T<SUB>x</SUB> MXene-based heterojunction (001-T/MX) can be used as a photocatalyst. </LI> <LI> Carbamazepine (CBZ) degradation under direct sunlight and ultraviolet light is studied. </LI> <LI> T/MX photocatalyst degrades 98.67% CBZ under UV light irradiation. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Thickness dependent magnetic and ferroelectric properties of LaNiO3 buffered BiFeO3 thin films

Shahzad Hussain,S.K. Hasanain,G. Hassnain Jaffari,S. Ismat Shah 한국물리학회 2015 Current Applied Physics Vol.15 No.3

BiFeO3 (BFO) thin films with thickness increasing from 40 to 480 nm were successfully grown on LaNiO3 (LNO) buffered Pt/Ti/SiO2/Si(100) substrate and the effects of thickness evolution on magnetic and ferroelectric properties are investigated. The LNO buffer layer promotes the growth and crystallization of BFO thin films. Highly (100) orientation is induced for all BFO films regardless of the film thickness together with the dense microstructure. All BFO films exhibited weak ferromagnetic response at room temperature and saturation magnetization is found to decrease with increase in film thickness. Well saturated ferroelectric hysteresis loops were obtained for thicker films; however, the leakage current dominated the ferroelectric properties in thinner films. The leakage current density decreased by three orders of magnitude for 335 nm film compared to 40 nm film, giving rise to enhanced ferroelectric properties for thicker films. The mechanisms for the evolution of ferromagnetic and ferroelectric characteristics are discussed.

Optimal Planning of Distributed Energy Storage Systems in Active Distribution Networks using Advanced Heuristic Optimization Techniques

Shahzad Kashif,Amin Arslan Ahmed 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.5

In this paper, the optimal planning of Distributed Energy Storage Systems (DESSs) in Active Distribution Networks (ADNs) has been addressed. As the proposed problem is mixed-integer, non-convex, and non-linear, this paper has used heuristic optimization techniques. In particular, fi ve optimization techniques namely Genetic algorithm, Particle swarm optimization, Tabu search, Simulated annealing, and Pattern search optimization techniques have been applied to optimal planning of DESS. The problem has been formulated to consider distributed storage units’ optimal locations and sizes to be placed in an ADN while respecting the constraints of the system. The problem has been addressed on two levels. In the fi rst level, an optimization technique is applied for DESS planning to determine the optimal solution and in the second level, the fi tness value of this solution is evaluated by solving a daily AC Optimal Power Flow (OPF) problem. Simulations have been done for the IEEE 34 and IEEE 123 nodes network to demonstrate and compare the effi ciency of diff erent optimization techniques. The comparison of these optimization techniques has shown that Particle swarm optimization and Tabu search optimization (with a particular value of tabu tenure found by hit and trial) have performed better in fi nding the lowest DESS location corresponding to minimum fi tness value as compared to other optimization techniques both for IEEE 34 nodes and IEEE 123 nodes network

Indoleacetic acid production and plant growth promoting potential of bacterial endophytes isolated from rice (Oryza sativa L.) seeds

Shahzad, Raheem,Waqas, Muhammad,Khan, Abdul Latif,Al-Hosni, Khadija,Kang, Sang-Mo,Seo, Chang-Woo,Lee, In-Jung AKADEMIAI KIADO BUDABPEST 2017 Biologia futura Vol.68 No.2

<P>Bacterial endophytes from the phyllosphere and rhizosphere have been used to produce bioactive metabolites and to promote plant growth. However, little is known about the endophytes residing in seeds. This study aimed to isolate and identify seed-borne bacterial endophytes from rice and elucidate their potential for phytohormone production and growth enhancement. The isolated endophytes included Micrococcus yunnanensis RWL-2, Micrococcus luteus RWL-3, Enterobacter soli RWL-4, Leclercia adecarboxylata RWL-5, Pantoea dispersa RWL-6, and Staphylococcus epidermidis RWL-7, which were identified using 16S rRNA sequencing and phylogenetic analysis. These strains were analyzed for indoleacetic acid (IAA) production by using GC-MS and IAA was found in the range of 11.50 +/- 0.77 mu g ml(-1) to 38.80 +/- 1.35 mu g ml(-1). We also assessed the strains for plant growth promoting potential because these isolates were able to produce IAA in pure culture. Most of the growth attributes of rice plants (shoot and root length, fresh and dry biomass, and chlorophyll content) were significantly increased by bacterial endophytes compared to the controls. These results show that IAA producing bacterial endophytes can improve host-plant growth traits and can be used as bio-fertilizers.</P>

APPROXIMATION METHODS FOR A COMMON MINIMUM-NORM POINT OF A SOLUTION OF VARIATIONAL INEQUALITY AND FIXED POINT PROBLEMS IN BANACH SPACES

Shahzad, N.,Zegeye, H. Korean Mathematical Society 2014 대한수학회보 Vol.51 No.3

We introduce an iterative process which converges strongly to a common minimum-norm point of solutions of variational inequality problem for a monotone mapping and fixed points of a finite family of relatively nonexpansive mappings in Banach spaces. Our theorems improve most of the results that have been proved for this important class of nonlinear operators.