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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.
Shahzad, Ahsan,Ko, Seunguk,Lee, Samgyu,Lee, Jeong-A,Kim, Kiseon IEEE 2017 IEEE SENSORS JOURNAL Vol.17 No.20
<P>Falls are a major cause of morbidity and long-term hospitalization among growing older population. An automated and accurate fall-risk assessment system is vital to identify high fall-risk population and to prevent falls by early intervention. Therefore, this paper provides an objective, cost-effective, and unsupervised method to obtain functional balance and mobility assessment-based fall-risk of community-dwelling older adults. More specifically, waist-mounted triaxial accelerometer signals acquired from directed routine (supervised control movements) are used to estimate the well-known clinical assessment score-Berg balance scale (BBS). The trunk acceleration signals are used to extract features and to find the optimal subset of features for each training data during repeated tenfold cross validation of the BBS estimation model. The average of two BBS estimates based on test and retest yielded a strong correlation rho = 0.86 with the standard BBS score. Also, high correlation (rho = 0.90) and low root-mean-square error (1.66) was observed between the two estimates of each subject. The proposed method is well suited for the assessment of balance impairment and pre-screening of quantitative fall-risk in an unsupervised setting. It has the potential to act as a surrogate of the standard clinical assessment-BBS.</P>
Reliable and Advanced Predictors for Corporate Financial Choices in Pakistan
SHAHZAD, Umeair,FUKAI, Luo,MAHMOOD, Faisal,JING, Liu,AHMED, Zahoor Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.7
Existing studies disagree over the core predictors of firm-level financial choices in developing countries. The general practice only validates the traditional capital structure model, which leads to inconsistency and a lack of novelty. This study removed overfitting issues among existing factors and presented the most reliable and advanced capital structure model in Pakistani firms. The panel data include 368 Pakistani companies from 19 non-financial sectors over the period 2004 to 2017. We apply Akaike and Bayesian Information Criteria to remove overfitting issues among inconsistent proxies in the capital structure model. The fixed effects regression is used for basic results and the Generalized Method of Moments is applied to control the endogeneity. Besides the conventional proxies, we report that credit rating, distance from bankruptcy, managerial concentration, and institutional quality are the most advanced capital structure determinants in Pakistan. These predictors remain significant across firm size and growth levels. Also, the findings confirm that new predictors are reliable to define capital structure dynamics and improve the speed of adjustment in overall and sub-sample analysis. The major findings suggest that managers and policymakers should consider these advanced predictors to design their financial settings in firms.
Dual targeting of EphA2 and FAK in ovarian carcinoma.
Shahzad, Mian M K,Lu, Chunhua,Lee, Jeong-Won,Stone, Rebecca L,Mitra, Rahul,Mangala, Lingegowda S,Lu, Yiling,Baggerly, Keith A,Danes, Christopher G,Nick, Alpa M,Halder, Jyotsnabaran,Kim, Hye-Sun,Vivas- Landes Bioscience 2009 Cancer Biology & Therapy Vol.8 No.11
<P>EphA2 gene silencing has been shown to result in antitumor efficacy. Here we considered whether silencing additional targets downstream of EphA2 would further enhance the therapeutic effect. EphA2 targeted siRNA was tested in combination with either FAK or Src targeted siRNA using DOPC nanoliposomes in orthotopic models of ovarian carcinoma. The effects of therapy were determined by changes in tumor weight, proliferation (Ki-67), and microvessel density (CD31). In our initial in vivo study, EphA2 plus FAK silencing resulted in the greatest reduction in tumor growth (by 73%, p < 0.005) as compared to control siRNA alone. In the SKOV3ip1 and HeyA8 ovarian cancer models, EphA2 siRNA-DOPC treatment resulted in a 50-67% decrease in tumor growth (p < 0.02, for both), and FAK siRNA-DOPC resulted in a 61-62% decrease in tumor growth (p < 0.009, p < 0.05, respectively). EphA2 plus FAK siRNA-DOPC treatment resulted in a significant reduction (SKOV3ip1: 76%, p < 0.007, HeyA8: 90%, p < 0.003) in tumor growth compared to control siRNA-DOPC. Combination treatment with EphA2 + FAK siRNA-DOPC resulted in significant decreases in tumor cell proliferation (p < 0.001) and microvessel density compared to control siRNA-DOPC (80%; p < 0.001), or the monotherapy groups (p values <0.001). These data suggest that the antitumor efficacy of in vivo EphA2 targeting is enhanced in combination with FAK silencing. Dual targeting of EphA2 and FAK may have therapeutic implications for ovarian cancer management.</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>
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.
Shahzad, F.,Abdullah, M.,Chaudhry, A.S.,Bhatti, J.A.,Jabbar, M.A.,Ahmed, F.,Mehmood, T.,Asim, M.,Ahmed, S.,Kamran, Z.,Irshad, I.,Tahir, M.N. Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.3
The study was carried out to explore the effects of replacing wheat straw with fungal treated wheat straw as an ingredient of total mixed ration (TMR) on the growth performance and nutrient digestibility in Nili Ravi buffalo male calves. Fungal treated wheat straw was prepared using Arachniotus sp. Four TMRs were formulated where wheat straw was replaced with 0 (TMR1), 33 (TMR2), 67 (TMR3), and 100% (TMR4) fungal treated wheat straw in TMR. All TMRs were iso-caloric and iso-nitrogenous. The experimental TMRs were randomly assigned to four groups of male calves (n = 6) according to completely randomized design and the experiment continued for four months. The calves fed TMR2 exhibited a significant improve in dry matter intake, average daily weight gain, feed conversion ratio and feed economics compared to other groups. The same group also showed higher digestibility of dry matter, crude protein, neutral-, and acid detergent fibers than those fed on other TMRs. It is concluded that TMR with 33% fungal-treated wheat straw replacement has a potential to give an enhanced growth performance and nutrient digestibility in male Nili Ravi buffalo calves.
Shahzad, Aasim,Kim, Woo-Sik,Yu, Taekyung The Royal Society of Chemistry 2016 Dalton transactions Vol.45 No.22
<P>This paper describes a simple and fast aqueous-phase route to the synthesis of Ag/AgCl hybrid nanostructures. These hybrid nanostructures were synthesized by reduction of AgCl nanoparticles with controlled shapes prepared by reacting Ag+ with Cl-in the presence of polyethyleneimine (PEI) in an aqueous-phase. We could easily control the morphology and composition of the nanostructures by varying the experimental conditions, including the reaction temperature and the amount of the reducing agent. The as-synthesized Ag/AgCl hybrid nanostructures exhibited enhanced photocatalytic activity and stability during the degradation of methyl orange under visible light irradiation because of their strong surface plasmon resonance (SPR) effect.</P>