Rehabilitation Design Program for Older People through Co-Design Activities

Tufail Muhammad,YangGyu Moon,KwanMyung Kim 한국디자인학회 2019 한국디자인학회 학술발표대회 논문집 Vol.2019 No.5

Assessing Employee Resilience to Economic Crisis

Muhammad Tufail,Marian Adusei 한국디자인학회 2016 한국디자인학회 학술발표대회 논문집 Vol.2016 No.10

Effects of cursor freeze time on the performance of older adult users on mouse-related tasks

Tufail, Muhammad,Kim, KwanMyung Elsevier 2017 Applied ergonomics Vol.65 No.-

<P><B>Abstract</B></P> <P>This study determines the optimum range of cursor freeze time (CFT) for basic target acquisition tasks. The effect of five levels of CFT was measured on double-clicking, clicking, and drag-and-drop operations, along with the inconvenience perceived by users at these levels. Older adult users find these standard mouse operations challenging because of slipping and accidental cursor movement. In this study, 24 older adult participants (13 males and 11 females) performed the abovementioned tasks repeatedly across five levels of CFT (0, 200, 400, 600, and 800 ms) and rated their perceived inconvenience at each level. CFT was found to have a significant effect on the three basic target acquisition tasks as well as the inconvenience perceived by participants. Performance on the drag-and-drop task was negatively influenced when the CFT was increased from 600 to 800 ms. The analysis suggests that a CFT of 200–400 ms is the optimum range for improved performance on the tasks.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Older adult users performed three mouse-related tasks at five levels of CFT. </LI> <LI> CFT varyingly influenced task performance and perceived inconvenience. </LI> <LI> The results suggest an optimum range of 200–400 ms for successful mouse tasks. </LI> </UL> </P>

Simultaneous Estimation of Azimuth and Elevation Angles and Frequency of Plane Wave Signals Using a Modified Matrix Pencil Method

Muhammad Faisal Khan,Muhammad Tufail 대한전자공학회 2008 ITC-CSCC :International Technical Conference on Ci Vol.2008 No.7

In this paper, the modified matrix pencil method [1] is extended from 2D to 3D for simultaneously estimating azimuth and elevation angles and frequency of multiple signals impinging on a volumetric array of sensors. Conventional matrix pencil method, which is used to estimate unknown parameters, needs a separate algorithm to associate the estimated components with each other to get proper groups of azimuth and elevation angles and frequencies of incoming signals [2]. The method proposed here automatically estimates unknown parameters in a group form, thereby bypassing the computationally expensive pairing operation. Moreover, simulation results show that grouping of unknown parameters using the proposed method is always correct in contrast to matrix pencil method whose results are sometimes erroneous.

Maintenance and Diagnostics Scenario Design for Prognostics and Health Management of Robots in Manufacturing Industries

Tufail Muhammad,Jae-eun Kim,Guk-hwa Im,KwanMyung Kim 한국디자인학회 2018 한국디자인학회 학술발표대회 논문집 Vol.2018 No.11

Effect of Elevated Temperature on Mechanical Properties of Limestone, Quartzite and Granite Concrete

Muhammad Tufail,Khan Shahzada,Bora Gencturk,Jianqiang Wei 한국콘크리트학회 2017 International Journal of Concrete Structures and M Vol.11 No.1

Although concrete is a noncombustible material, high temperatures such as those experienced during a fire have a negative effect on the mechanical properties. This paper studies the effect of elevated temperatures on the mechanical properties of limestone, quartzite and granite concrete. Samples from three different concrete mixes with limestone, quartzite and granite coarse aggregates were prepared. The test samples were subjected to temperatures ranging from 25 to 650 『C for a duration of 2 h. Mechanical properties of concrete including the compressive and tensile strength, modulus of elasticity, and ultimate strain in compression were obtained. Effects of temperature on resistance to degradation, thermal expansion and phase compositions of the aggregates were investigated. The results indicated that the mechanical properties of concrete are largely affected from elevated temperatures and the type of coarse aggregate used. The compressive and split tensile strength, and modulus of elasticity decreased with increasing temperature, while the ultimate strain in compression increased. Concrete made of granite coarse aggregate showed higher mechanical properties at all temperatures, followed by quartzite and limestone concretes. In addition to decomposition of cement paste, the imparity in thermal expansion behavior between cement paste and aggregates, and degradation and phase decomposition (and/or transition) of aggregates under high temperature were considered as main factors impacting the mechanical properties of concrete. The novelty of this research stems from the fact that three different aggregate types are comparatively evaluated, mechanisms are systemically analyzed, and empirical relationships are established to predict the residual compressive and tensile strength, elastic modulus, and ultimate compressive strain for concretes subjected to high temperatures.

Effect of Elevated Temperature on Mechanical Properties of Limestone, Quartzite and Granite Concrete

Tufail, Muhammad,Shahzada, Khan,Gencturk, Bora,Wei, Jianqiang Korea Concrete Institute 2017 International Journal of Concrete Structures and M Vol.11 No.1

Although concrete is a noncombustible material, high temperatures such as those experienced during a fire have a negative effect on the mechanical properties. This paper studies the effect of elevated temperatures on the mechanical properties of limestone, quartzite and granite concrete. Samples from three different concrete mixes with limestone, quartzite and granite coarse aggregates were prepared. The test samples were subjected to temperatures ranging from 25 to $650^{\circ}C$ for a duration of 2 h. Mechanical properties of concrete including the compressive and tensile strength, modulus of elasticity, and ultimate strain in compression were obtained. Effects of temperature on resistance to degradation, thermal expansion and phase compositions of the aggregates were investigated. The results indicated that the mechanical properties of concrete are largely affected from elevated temperatures and the type of coarse aggregate used. The compressive and split tensile strength, and modulus of elasticity decreased with increasing temperature, while the ultimate strain in compression increased. Concrete made of granite coarse aggregate showed higher mechanical properties at all temperatures, followed by quartzite and limestone concretes. In addition to decomposition of cement paste, the imparity in thermal expansion behavior between cement paste and aggregates, and degradation and phase decomposition (and/or transition) of aggregates under high temperature were considered as main factors impacting the mechanical properties of concrete. The novelty of this research stems from the fact that three different aggregate types are comparatively evaluated, mechanisms are systemically analyzed, and empirical relationships are established to predict the residual compressive and tensile strength, elastic modulus, and ultimate compressive strain for concretes subjected to high temperatures.

Stabilisation of locally Lipschitz non-linear systems under input saturation and quantisation

Rehan, Muhammad,Tufail, Muhammad,Ahn, Choon Ki,Chadli, Mohammed IET 2017 IET CONTROL THEORY AND APPLICATIONS Vol.11 No.9

<P>This study addresses the control of locally Lipschitz non-linear systems under quantisation and input saturation non-linearities. The non-linear dynamics of the systems are taken to be locally Lipschitz, rather than the conventional globally Lipschitz counterpart, to consider a generalised form of the Lipschitz non-linear systems. An ellipsoidal region containing the origin is constructed, for which the non-linear dynamics satisfy the Lipschitz condition in contrast to the conventional approaches. Saturation and quantisation non-linearities are dealt using a generalised local sector condition and a bound on the quantisation noise. A regional control strategy for the stabilisation of non-linear systems using state feedback is devised by employing these conditions, which is further extended to attain robustness against external perturbations. The proposed control strategies guarantee convergence of the states of a non-linear system inside a bounded reducible region in the neighbourhood of the origin. In contrast to the conventional approaches, the present study considers ellipsoidally Lipschitz non-linear systems, supports various types of quantisers, ensures attenuation of the disturbances, and provides a clear picture of the region of stability. An example of the application of the proposed control strategies for a modified Chua's circuit is demonstrated.</P>

A Novel Method for Guaranteed Overflow Oscillation Elimination in Digital Filters Subject to Quantization

Rehan, Muhammad,Mobeen, Muhammad Bilal,Tufail, Muhammad,Ahn, Choon Ki IEEE 2018 IEEE transactions on circuits and systems. a publi Vol.65 No.9

<P>This brief provides a novel criterion for the analysis of convergence of states of an infinite impulse response (IIR) digital filter to a bounded region under the influence of composite effects of quantization and overflow nonlinearities. The developed criterion is less conservative in its approach in terms of analyzing stability than conventional methods and can be employed for implementation of an IIR filter on comparatively smaller hardware word-length than existing methods. The conventional approaches consider asymptotic stability of a filter with respect to the quantization noise; however, quantization in digital filters can result into bounded oscillation and lead to infeasibility of the asymptotic stability. Therefore, a less conservative stability analysis together with estimation of steady-state region of convergence for an IIR filter is provided. In addition, the conventional approaches, analyzing stability, and steady-state region of convergence, may not guarantee an overflow oscillation-free realization of a filter. Consequently, a condition for estimating the steady-state region of convergence (along with the filter stability) with an additional constraint that the filter’s state should not overflow in the bounded region has been derived. A comparative analysis with conventional methods is provided in simulation results.</P>

Behavioral response of Nilaparvata lugens (Stål), Cyrtorhinus lividipennis Reuter and Paederus fuscipes Curtis to three synthetic volatile chemical compounds

Khan Muhammad Musa,Huang Qing,Wagan Tufail Ahmed,Hua Hongxia,Cai Wanlun,Zhao Jing 한국응용곤충학회 2020 Journal of Asia-Pacific Entomology Vol.23 No.2

Plant essential oils (EOs) and a wide range of chemicals affect insect pests in many ways, such as via stimulatory, deterrent, toxic and hormonal effects. Three different compounds ((E)-β-caryophyllene (E-β-C), D-limonene (Dlime) and trans-2-dodecenol (T-2-D)) were tested against Nilaparvata lugens, Cyrtorhinus lividipennis and Paederus fuscipes, and their behavioral response was assessed. The results showed that on average, more N. lugens nymphs were repelled by E-β-C and T-2-D than by D-lime. More C. lividipennis nymphs were attracted to T-2-D and D-lime than to E-β-C. However, P. fuscipes displayed no significant response to the three chemical compounds. The results also demonstrated that T-2-D has exerted significant repellency against N. lugens and a significant attraction for C. lividipennis, while E-β-C and D-lime have no significant effect on any tested insect. T-2-D was selected and tested in a greenhouse under semi-field conditions, where the observations confirmed the results of the laboratory experiments. From the results, it can be concluded that T-2-D at a concentration of 0.06 g/L is an effective synthetic volatile chemical compound and is the strongest repellent of N. lugens and the strongest attractant for C. lividipennis. This synthetic chemical compound can be used as a pest management tool in rice agroecosystems.