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.

The Sensors Connectivity within SCADA Automation Environment and New Trends for Security Development during Multicasting Routing Transmission

Shahzad, Aamir,Udagepola, Kalum Priyanath,Lee, Young-keun,Park, Soojin,Lee, Malrey SAGE Publications 2015 INTERNATIONAL JOURNAL OF DISTRIBUTED SENSOR NETWOR Vol.2015 No.-

<P>This study examined the security of SCADA system and its protocols, more specifically, SCADA/DNP3 protocol security. To achieve the study goals, a SCADA simulation environment is designed for water pumping process through connectivity of intelligent sensors, the payload is constructed, and security is deployed inside DNP3 protocol stack and then bytes are multicast to subcontrollers.</P>

Observation of photoluminescence from large-scale layer-controlled 2D ß-Cu₂S synthesized by the vapor-phase sulfurization of copper thin films

Shahzad, Rauf,Kim, TaeWan,Mun, Jihun,Kang, Sang-Woo IOP Pub 2017 Nanotechnology Vol.28 No.50

<P>Two-dimensional (2D) copper chalcogenides (Cu<SUB>2−<I>x</I> </SUB> <I>X</I> where <I>X</I>?=?S, Se, Te) have had much attention regarding various applications due to their remarkable optical and electrical properties, abundance, and environmentally friendly natures. This work indicates that highly uniform Cu<SUB>2−<I>x</I> </SUB>S (where 0?<U><</U>?<I>x</I>?<U><</U>?1) nanosheets can be obtained by the two-step method of Cu deposition by sputtering with precisely controlled and extremely low growth rate followed by vapor-phase sulfurization. The phase transformations of thin Cu<SUB>2−<I>x</I> </SUB>S films upon the Cu seed layer thickness are investigated. A unique thickness-constrained synthesis process using vapor-phase sulfurization is employed here, which evolves from a vertical to lateral growth mechanism based on the optimization of the Cu seed layer thickness. Atomically thin 2D <I>β</I>-Cu<SUB>2</SUB>S film was successfully synthesized using the thinnest Cu seed film. We have systematically investigated the phase- and thickness-dependent optical properties of Cu<SUB>2−<I>x</I> </SUB>S films at room temperature. Micro-photoluminescence (PL) spectroscopy reveals that the 2D <I>β</I>-Cu<SUB>2</SUB>S film possesses a direct band gap with an energy of 1.1 eV while the PL intensities are greatly suppressed in the multilayer Cu<SUB>2−<I>x</I> </SUB>S (where 0?≤?<I>x</I>?<U><</U>?1).</P>

Sulfur-doped graphene laminates for EMI shielding applications

Shahzad, Faisal,Kumar, Pradip,Yu, Seunggun,Lee, Seunghwan,Kim, Yoon-Hyun,Hong, Soon Man,Koo, Chong Min The Royal Society of Chemistry 2015 Journal of Materials Chemistry C Vol.3 No.38

<▼1><P>Herein, for the first time, we demonstrate that a laminated structure of sulfur-doped reduced graphene oxide (SrGO) provides significant potential for electromagnetic interference shielding applications.</P></▼1><▼2><P>Herein, for the first time, we demonstrate that a laminated structure of sulfur-doped reduced graphene oxide (SrGO) provides significant potential for electromagnetic interference shielding applications. In this study, SrGO was prepared through the reaction between graphene oxide and hydrogen disulfide (H2S) gas at elevated temperatures. The doping degree of S was controlled through varying the time and temperature of the reaction and the maximum doping content of 5.6 wt% was achieved. Because of the n-type doping contribution of the S atom to the doped graphene, SrGO laminate not only revealed a 47% larger electrical conductivity (75 S cm<SUP>−1</SUP>) than undoped reduced graphene oxide laminate (51 S cm<SUP>−1</SUP>) but also revealed 119% larger EMI shielding effectiveness (33.2 dB) than the undoped one (15.5 dB) at the same sample thickness.</P></▼2>

Seed-borne endophytic Bacillus amyloliquefaciens RWL-1 produces gibberellins and regulates endogenous phytohormones of Oryza sativa

Shahzad, R.,Waqas, M.,Khan, A.L.,Asaf, S.,Khan, M.A.,Kang, S.M.,Yun, B.W.,Lee, I.J. Gauthier-Villars ; Elsevier Science Ltd 2016 Vol. No.

<P>Some microorganisms are adapted to an endophytic mode, living symbiotically with plants through vertical transmission in seeds. The role of plant growth-promoting endophytes has been well studied, but those of seed-associated endophytic bacteria are less understood. The current study aimed to isolate and identify bacterial endophytes associated with rice (Oryza sativa L. 'Jin so mi') seeds, their potential to produce gibberellins (GAs), and role in improving host-plant physiology. The isolated bacterial endophyte RWL-1 was identified as Bacillus amyloliquefaciens by using 16S rRNA sequencing and phylogenetic analysis. The pure culture of B. amyloliquefaciens RWL-1, supplied with deuterated internal standards, was subjected to gas chromatography and mass spectrometric selected ion monitoring (GC-MS/SIM) for quantification of GAs. Results showed the presence of GAs in various quantities (ng/mL) viz., GA(20) (17.88 +/- 4.04), GA(36) (5.75 +/- 2.36), GA(24) (5.64 +/- 2.46), GA(4) (1.02 +/- 0.16), GA(53) (0.772 +/- 0.20), GA(9) (0.12 +/- 0.09), GA(19) (0.093 +/- 0.13), GA(5) (0.08 +/- 0.04), GA(12) (0.014 +/- 0.34), and GA(8) (0.013 +/- 0.01). Since endogenous seed GAs are essential for prolonged seed growth and subsequent plant development, we used exogenous GA(3) as a positive control and water as a negative control for comparative analysis of the application of B. amyloliquefaciens RWL-1 to rice plants. The growth parameters of rice plants treated with endophytic bacterial cell application was significantly increased compared to the plants treated with exogenous GA3 and water. This was also revealed by the significant up-regulation of endogenous GA(1) (17.54 +/- 2.40 ng), GA(4) (310 +/- 5.41 ng), GA(7) (192.60 +/- 3.32 ng), and GA(9) (19.04 +/- 2.49 ng) as compared to results of the positive and negative control treatments. Rice plants inoculated with B. amyloliquefaciens RWL-1 exhibited significantly higher endogenous salicylic acid (1615.06 +/- 10.81 mu g), whereas endogenous abscisic acid (23.31 +/- 2.76 ng) and jasmonic acid (25.51 +/- 4.20 ng) were observed to be significantly lower in these inoculated plants than in those treated with exogenous GA3 and water. Results of the present study suggest that B. amyloliquefaciens RWL-1 has the ability to produce GAs and that its inoculation in seedlings can be beneficial to rice plants. Broader field trials should be conducted to determine its use as an alternative biofertilizer. (C) 2016 Elsevier Masson SAS. All rights reserved.</P>

Foliar application of methyl jasmonate induced physio-hormonal changes in Pisum sativum under diverse temperature regimes

Shahzad, R.,Waqas, M.,Khan, A.L.,Hamayun, M.,Kang, S.M.,Lee, I.J. Gauthier-Villars ; Elsevier Science Ltd 2015 Vol. No.

Global climate change brings with it unwarranted shifts in both abiotic (heat stress, cold stress, wind, precipitation) and biotic (pathogens, pests) environmental factors, thus posing a threat to agricultural productivity across the world. In plants, lodging due to storms or herbivory causes wounding stress and consequently enhances endogenous jasmonates. In response, the plant growth is arrested as plant defense is prioritized. We pre-treated pea plants with elevated methyl jasmonate (MeJA) levels i.e. 50 μM, 100 μM and 200 μM under controlled growth chamber conditions. The pre-treated plants were then kept at 40 <SUP>o</SUP>C (heat stress-HS), 4 <SUP>o</SUP>C (cold stress-CS) and 20 <SUP>o</SUP>C (optimum/control temperature-OT) for 72 h. The effect of such treatments on plant growth attributes, photosynthesis, stomatal conductance, cell death rate, and regulation of endogenous hormones were observed. Elevated MeJA application hindered plant growth attributes under HS, CS and OT conditions. Moreover, elevated MeJA levels lowered the rate of photosynthesis and stomatal conductance, induced stomatal closure, caused higher cells mortality in leaves under HS, CS, and OT conditions. Endogenous ABA contents significantly declined in all MeJA treatments under HS and OT, but increased under CS conditions. Exogenous MeJA enhanced endogenous jasmonic acid contents of pea plants, but altered endogenous salicylic acid contents under varying temperatures. Current study shows that higher concentrations of exogenous MeJA strengthen plant defense mechanism by hindering plant growth under stress conditions.

An Improved Method of Organogenesis from Cotyledon Callus of Acacia sinuata (Lour.) Merr. using Thidiazuron

Shahzad Anwar,Ahmad Naseem,Anis Mohammad The Korean Society of Plant Biotechnology 2006 Plant molecular biology and biotechnology research Vol.8 No.1

An efficient protocol for in vitro multiple shoot bud induction and plant regeneration from mature green cotyledon derived callus tissues of Acacia sinuata has been developed. Callus formation occurs at all the concentrations of thidiazuron (TDZ) in Murashige and Skoog's (MS) medium, but 0.6 ${\mu}M$ proved to be the best with maximum callus formation frequency. Supplementation of TDZ in combination with indole-acetic acid (IAA) in MS media accelerates shoot bud organogenesis in differentiating callus tissues with 60-70% conversion of shoot buds into shoot Most efficient shoot organogenesis was recorded when TDZ induced calli were subcultured at different concentrations of 6-benzyla-denine (BA). Optimum shoot bud induction and plant regeneration from callus was achieved when 0.6 ${\mu}M$ (TDZ) induced calli were subcultured at 3.0 ${\mu}M$ (BA) where $16.6{\pm}0.74$ shoots/unit callus on obtained. Rooting in in vitro differentiated shoots was achieved when transferred to medium containing different concentration of indole-3-butyric acid (IBA) in full & half strength MS medium. The well rooted plantlets were hardened and transferred to net house with 90% survival rate.

Electrowetting in a water droplet with a movable floating substrate

Shahzad, Amir,Masud, A. R.,Song, Jang-Kun American Physical Society 2016 Physical review. E Vol.93 No.5

An improved indirect evaporative cooler experimental investigation

Shahzad, Muhammad Wakil,Burhan, Muhammad,Ybyraiymkul, Doskhan,Oh, Seung Jin,Ng, Kim Choon ELSEVIER 2019 Applied Energy Vol. No.

<P><B>Abstract</B></P> <P>Air conditioning has enhanced the work efficiency and improved life style by maintaining comfortable environment. The growing demand of air conditioning has negative impact on energy and environment. In 2015, air conditioning consumed 6% of total global electricity produced and it is expected to increase to 20% by 2050. The leveling-off conventional chiller’s efficiency at 0.85 ± 0.03 kW/Rton due to pairing of dehumidification and cooling processes in one machine is not only the major reason of high energy consumption but also the key limitation in efficiency improvement. The de-coupling of dehumidification and cooling processes can be one of the solution to achieve the quantum jump in the performance, 0.6 ± 0.03 kW/Rton, by improving individual processes. We proposed an improved indirect evaporative cooler system for sensible cooling that can be combined with dehumidification processes to achieve sustainable cooling goals. The experimentation on 800 mm long and 280 mm wide generic cell showed that it can produce temperature differential up to 10 °C with small area of heat transfer. It was showed that the proposed vertical heat exchanger configuration with multi point injection of working air is the best configuration of the indirect evaporative cooler, achieving coefficient of performance level of 78 for cooling alone. We expect that overall coefficient of performance level of 7–8 is achievable by incorporating efficient dehumidification processes. We also presented detailed design parameters that can be used as a reference for commercial system design.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Decoupling of latent and sensible load in cooling is the key for sustainability. </LI> <LI> The indirect evaporative cooler integrated with dehumidification is one of the solution. </LI> <LI> Improved IEC with three major modification can achieve COP up to 78 for cooling only. </LI> <LI> The dehumidification system COP around 4–5 can help to achieve overall COP of 7–8. </LI> <LI> The proposed multi injection vertical heat exchanger design has the best performance. </LI> </UL> </P>

Performance and cost-benefit analysis of anaerobic moving bed biofilm reactor for pretreatment of textile wastewater

Shahzad Hafiz Muhammad Aamir,Khan Sher Jamal,Khan Musharib,Schönberger Harald,Weber Frank-Andreas 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.6

Performance of an anaerobic moving bed biofilm reactor (AnMBBR) was evaluated for pretreatment of real textile desizing wastewater at organic loading rate (OLR) of 1±0.05 to 6.3±0.37 kgCOD/m3/d. After OLR optimization, the performance of AnMBBR was evaluated for biodegradation of reactive dyes. AnMBBR was operated under a mesophilic temperature range of 30 to 36 °C, while the oxidation-reduction potential (ORP) and pH were in the range of 504 to 594 (-mV) and 6.98 to 7.28, respectively. By increasing the OLR from 1±0.05 to 6.3±0.37 kgCOD/m3/d, COD and BOD5 removal was decreased from 84 to 39% and 89 to 49%, respectively. While the production of biogas was increased from 0.12 to 0.83 L/L·d up to an optimum OLR of 4.9±0.43 kgCOD/m3/d. With increase in the dye concentration in the feed, COD, BOD5, color removal and biogas production reduced from 56, 63, 70% and 0.65 L/L·d to 34, 43, 41% and 0.08 L/L·d, respectively. Based on the data obtained, a cost-benefit analysis of AnMBBR was also investigated for the pretreatment of real textile desizing wastewater. Cost estimation of anaerobic pretreatment of textile desizing wastewater indicated a net profit of 21.09 million PKR/yr (114,000 €/yr) and a potential payback period of 2.54 years.