Exponential Stabilization of a Class of Underactuated Mechanical Systems using Dynamic Surface Control

Nadeem Qaiser,Naeem Iqbal,Amir Hussain,Naeem Qaiser 대한전기학회 2007 International Journal of Control, Automation, and Vol.5 No.5

This paper proposes a simpler solution to the stabilization problem of a special class of nonlinear underactuated mechanical systems which includes widely studied benchmark systems like Inertia Wheel Pendulum, TORA and Acrobot. Complex internal dynamics and lack of exact feedback linearizibility of these systems makes design of control law a challenging task. Stabilization of these systems has been achieved using Energy Shaping and damping injection and Backstepping technique. Former results in hybrid or switching architectures that make stability analysis complicated whereas use of backstepping some times requires closed form explicit solutions of highly nonlinear equations resulting from partial feedback linearization. It also exhibits the phenomenon of explosions of terms resulting in a highly complicated control law. Exploiting recently introduced Dynamic Surface Control technique and using control Lyapunov function method, a novel nonlinear controller design is presented as a solution to these problems. The stability of the closed loop system is analyzed by exploiting its two-time scale nature and applying concepts from Singular Perturbation Theory. The design procedure is shown to be simpler and more intuitive than existing designs. Design has been applied to important benchmark systems belonging to the class demonstrating controller design simplicity. Advantages over conventional Energy Shaping and Backstepping controllers are analyzed theoretically and performance is verified using numerical simulations.

Isolation and Biocontrol Potential of Bacillus amyloliquefaciens Y1 against Fungal Plant Pathogens

Qaiser Jamal,Yong Seong Lee,Hyeon Deok Jeon,Yun Suk Park,Kil Yong Kim 한국토양비료학회 2015 한국토양비료학회지 Vol.48 No.5

This study was performed to investigate thermophilic bacteria from soil having broad antifungal spectrum against Rhizoctonia solani, Colletotrichum gloeosporioides, Phytophthora capsici, Fusarium oxysporum f.sp. lycopersici, and Botrytis cinerea. One isolate selected could resist heat shock of 60°C for one hour, and had broad antifungal activity in dual culture assay against all tested fungal pathogens and was identified as Bacillus amyloliquefaciens Y1 using 16S rRNA gene sequence. Further investigation for antifungal activity of bacterial culture filtrate (BCF) and butanol crude extract (BCE) of various concentrations showed broad spectrum antifungal activity and fungal growth inhibition significantly increased with increasing concentration with highest growth inhibition of 100% against R. solani with 50% BCF and 11 mm of zone of inhibition against R. solani with 4 mg BCE concentration. Treatment of butanol crude extract resulted in deformation, lysis or degradation of C. gloeosporioides and P. capsici hyphae. Furthermore, B. amyloliquefaciens Y1 produced volatile compounds inhibiting growth of R. solani (70%), C. gloeosporioides (65%) and P. capsici (65-70%) when tested in volatile assay. The results from the study suggest that B. amyloliquefaciens Y1 could be a biocontrol candidate to control fungal diseases in crops.

Visualization, Economic Complexity Index, and Forecasting of South Korea International Trade Profile: A Time Series Approach

Qaiser Farooq Dar,Gulbadin Farooq Dar,Jin-Hee Ma,Young-Hyo Ahn 한국무역학회 2020 Journal of Korea trade Vol.24 No.1

Purpose – The recent growth of South Korean products in the international market is the benchmark for both developed as well as developing countries. According to the development index, the role of international trade is indeed crucial for the development of the national economy. However, the visualization of the international trade profile of the country is the prerequisite of governmental policy decision-makers and guidance for forecasting of foreign trade. Design/methodology – We have utilized data visualization techniques in order to visualize the import & export product space and trade partners of South Korea. Economic Complexity Index (ECI) and Revealed Comparative Advantage (RCA) were used to identify the Korean international trade diversification, whereas the time series approach is used to forecast the economy and foreign trade variables. Findings – Our results show that Chine, U.S, Vietnam, Hong Kong, and Japan are the leading trade partners of Korea. Overall, the ECI of South Korea is growing significantly as compared to China, Hong Kong, and other developed countries of the world. The expected values of total import and export volume of South Korea are approximately US$535.21 and US$ 781.23B, with the balance of trade US$ 254.02B in 2025. It was also observed from our analysis that imports & exports are equally substantial to the GDP of Korea and have a significant correlation with GDP, GDP per capita, and ECI. Originality/value – To maintain the growth rate of international trade and efficient competitor for the trade partners, we have visualized the South Korea trade profile, which provides the information of significant export and import products as well as main trade partners and forecasting.

Purchasing Power Parity of ASEAN-5 Countries Revisited: Heterogeneity, Structural Breaks and Cross-sectional Dependence

Qaiser Munir,Sook Ching Kok 연세대학교 동서문제연구원 2015 Global economic review Vol.44 No.1

This paper tests the purchasing power parity (PPP) hypothesis for a collection of ASEAN-5 countries using monthly data spanning the period 1968:1–2009:11. For this purpose, a number of recently developed more powerful panel unit root tests that permit for dependence among the individual countries are employed. In addition to this, we utilize the Lagrange multiplier (LM) cointegration test developed by Westerlund, which is flexible enough to accommodate a large degree of country specific heterogeneity, cross-country dependence as well as multiple structural breaks. The main results derived from this study are: first, our findings from panel unit root tests which do not control for cross-sectional dependence appear to be clearly showing evidence against PPP. Second, the evidence from panel tests controlling for crosssectional dependence is against PPP over the whole and 1997 pre-financial crisis periods. On the other hand, we find sufficient evidence to support PPP for ASEAN-5 countries over the postfinancial crisis period. Third, in stark contrast stand the results obtained from the application of the panel cointegration test provide strong evidence of panel cointegration in whole and subperiods, providing evidence for PPP; however, these findings have become apparent after allowing for multiple structural breaks as well as for general forms of cross-sectional dependence through bootstrap methods. We provide a detailed description of the breaks identified in the analysis, which appear to be closely associated with some macroeconomic shocks and institutional arrangements. The findings of this study offer important policy implications.

Effect of machining parameters on surface quality and delamination of carbon/glass/epoxy hybrid composite material during end milling operation

Qaiser Saghir,Atta ur Rehman Shah,S. Kamran Afaq,Tanveer Ahmed,송정일 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.5

Glass, carbon, and hybrid/glass/carbon-reinforced polymer composites are the most important materials used in defense, aerospace, automobile, and sports industry because of their excellent mechanical properties. End-milling process is the final and important machining process of composites to achieve the desired shape and dimensions. The main concern of this research is to minimize delamination and surface roughness in carbon/glass/epoxy hybrid composites after end milling. The effects of tool material, spindle speed, feed rate, and cut depth on delamination and surface quality were investigated. Taguchi design of experiment method was used to vary the machining parameters. Surface quality was examined by a surface roughness tester, and the delamination of milled surfaces was inspected by non-destructive technique using ultrasonic testing. The surface morphology of milled surfaces was studied by scanning electron microscopy. Results were verified by signal-to-noise ratio and analysis of variance technique. Carbon/glass/epoxy hybrid composite exhibited better surface finish with diamond flute end mill cutter, spindle speed of 1500 rpm, feed rate of 0.15 mm/min, and cut depth of 0.05 mm. After nondestructive testing, minimum delamination in carbon/glass/epoxy hybrid composite was found using diamond flute end mill cutter at a spindle speed of 1500 rpm, feed rate of 0.10 mm/ min, and cut depth of 0.10 mm.

Hybrid Rice Promotes Ammonia Oxizing Baceria Relative to Ammonia Oxidizing Archaea in Rhizosphere at Different Growing Stages

Qaiser Hussain,Genxing Pan 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Assessing Efficiency and Ranking of English Premier League Strikers Using Data Envelopment Analysis

Qaiser Farooq Dar,Zahoor, Ul Haqbhat,마진희,안영효 한국상품학회 2022 商品學硏究 Vol.40 No.6

Performance evaluation and ranking of sports players have always been important objectives for decision-making in the sports industry. In this study, we introduce a powerful non-parametric methodology for the evaluation of performance and ranking based on the efficiency of players using Data Envelopment Analysis (DEA). The goal of this work is to provide a methodology to improve efficiency of players to provide valuable benchmark information to the management of football clubs, their coaches, decision-makers, and football players. The study is based on the efficiency of strikers (forwards and midfielders) for the 2020-21 season of the English Premier League. The aggregate, technical, scale, and super efficiencies were estimated along with the nature of returns to scale and ranking in the case of forward and midfielder players separately by using the DEA approaches. Further, the study is extended to compare the mean efficiency of both types of strikers and the efficiency estimated by radial and non-radial approaches of DEA. Finally, based on our data analysis, we reported that the averages of radial and non-radial technical efficiency of forward strikers are ( .89) and ( .71), whereas the midfielder strikers are ( .83) and ( .66). It was also observed that the aggregate and scale efficiency of forward and midfielder strikers are statistically significant as competed to the technical and super efficiency.

JOINING OF CIRCUITS IN PSL(2; Z)-SPACE

Qaiser Mushtaq,Abdul Razaq 대한수학회 2015 대한수학회보 Vol.52 No.6

The coset diagrams are composed of fragments, and the fragments are further composed of circuits at a certain common point. A condition for the existence of a certain fragment γ of a coset diagram in a coset diagram is a polynomial f in Z[z]: In this paper, we answer the question: how many polynomials are obtained from the fragments, evolved by joining the circuits (n; n) and (m;m) ; where n < m, at all points.

Investigate Central Bank Efficiency and its relation with Export level: A Case of Top Asian Exporter Countries

QAISER FAROOQ DAR,Ahn Young Hyo 한국무역학회 2019 한국무역학회 국제학술대회 Vol.2019 No.08

Numerical Modeling of Fracture-Resistant Sn Micropillars as Anode for Lithium Ion Batteries

Qaiser, Nadeem,Kim, Yong Jae,Hong, Chung Su,Han, Seung Min American Chemical Society 2016 The Journal of Physical Chemistry Part C Vol.120 No.13

<P>Sn possesses three times higher capacity in comparison to graphite anode (372 mAhg(-1)) that makes it a promising candidate for enhanced performance Li ion batteries. Contrary to Si, Sn is compliant and ductile in nature and thus is expected to readily relax the Li diffusion-induced stresses. The low melting point of Sn additionally allows for stress relaxations from time-dependent or creep deformations even at room temperature. In this study, numerical modeling is used to reveal the significance of plasticity and creep-based stress relaxations in the Sn working electrode. The maximum elastic tensile hoop stresses for 1 mu m micropillar size with 1C charging rate conditions reduces down from similar to 1 GPa to similar to 200 MPa when Sn is allowed to plastically deform at a yield strength of similar to 150 MPa. After experimentally determining the creep response of Sn micropillars, creep deformations are incorporated in numerical modeling to show that the maximum tensile hoop stress is further reduced to similar to 0.45 MPa under the same conditions. Lastly, the Li-induced stresses are analyzed for different micropillar sizes to evaluate the critical size to prevent fracture, which is determined to be similar to 5.3 mu m for C/10 charging rate, which is significantly larger than that in Si.</P>