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991.
Simultaneous Use of Runs Rules and Auxiliary Information With Exponentially Weighted Moving Average Control Charts 下载免费PDF全文
Waqas Arshad Nasir Abbas Muhammad Riaz Zawar Hussain 《Quality and Reliability Engineering International》2017,33(2):323-336
Quality has become a key determinant of success in all aspects of industry. Exponentially weighted moving average control chart is an important tool of statistical process control used to monitor and improve quality of industrial processes. To enhance the performance of control charts, there are many strategies including the choice of an efficient plotting statistic, the choice of an efficient sampling design, the application of runs rules, and the use auxiliary information among many others. In this study, we propose nine different signaling schemes to enhance the performance of an exponentially weighted moving average control chart for location parameter, which is based on the exploitation of auxiliary information. Performance evaluation of the proposed schemes is carried out in terms of average run length. Comparisons of proposals are made with the classical as well as the auxiliary based exponentially weighted moving average and cumulative sum charts, which indicate that the proposed schemes perform better than the comparative counterparts under discussion. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
992.
Muhammad Fahad Usman Arshad Hussain Farah Nadeem 《International Journal of Wireless Information Networks》2014,21(2):101-113
The IEEE 802.11e EDCA is designed to provide quality of support for real time applications with stringent latency and throughput requirements. Theoretical frameworks for analysis of throughput performance of wireless LAN employing exponential back-off exist extensively. Several models rely on simplification assumptions that preclude their direct applicability to the enhanced distributed coordination access (EDCA) which uses heterogeneous protocol parameters, while other models are exceedingly complex to analyze. In this paper, a tractable analytical model is proposed for saturation throughput of the IEEE 802.11e EDCA. The prioritization through channel access parameters including the AIFS and contention window is catered for within a three dimensional Markov chain. The integration of back-off counter freezing and retry limit enhance the models precision. Its validation is done by simulation on NS-2. Practical applicability of the model is established based on accuracy and computational efficiency. The model is utilized for throughput analysis of the EDCA under saturated traffic loads. 相似文献
993.
Zareei Hassan Mohd. Yusuff Rosnah Mohd. Salit Sapuan Norazizan S.A.R. Sharifah Hussain Mohd. Rizal 《Universal Access in the Information Society》2017,16(2):425-433
Universal Access in the Information Society - The increasing elderly population and their specific needs have challenged communication technology developers regarding the usability of their... 相似文献
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Arshad Hussain Sirajul Haq Marjan Uddin 《Engineering Analysis with Boundary Elements》2013,37(11):1351-1366
We investigate numerical solution of the one dimensional nonlinear Klein–Gordon and two-dimensional sine-Gordon equations by meshless method of lines using radial basis functions. Results are compared with some earlier work showing the efficiency of the applied method. Salient feature of this method is that it does not require a mesh in the problem domain. Multiquadric and Gaussian are used as radial basis functions, which use a shape parameter. Choice of the shape parameter is still an open problem. We explore optimal value of the shape parameter without applying any extra treatment. For multiquadric, eigenvalue stability is studied without enforcing the boundary conditions whereas for Gaussian, the boundary conditions are enforced. 相似文献
996.
Hussain A. Alzaher Noman A. Tasadduq 《AEUE-International Journal of Electronics and Communications》2013,67(10):898-904
A new 4th-order reconfigurable (complex bandpass or normal lowpass) filter for implementing the channel select filter for dual-mode receivers adopting low-IF for Bluetooth (BT) and zero-IF for WLAN (IEEE 802.11b) is presented. It provides an alternative solution to the optimum low-power complex filter based on the current amplifier. The new filter avoids the employment of capacitor and/or resistor banks leading to an area efficient design solution while maintaining high linearity and relatively low power consumption. The center frequency in BT mode and the pole frequency in 802.11b mode are digitally tuned through programming active current division networks (CDNs). Experimental results obtained from 0.18 μm CMOS chips show that the proposed design offers improved characteristics over available solutions in terms of power consumption, spurious-free dynamic range (SFDR) and/or area. It achieves in-band SFDR of 65.3 dB for BT and 65.2 dB for 802.11b while it consumes 1.8 mW. Also, it offers image rejection of better than 59 dB. 相似文献
997.
Chitosan oligomers (average Dp-4) are known for their antifungal activity and wood decay resistance. These oligomers are susceptible to moisture, and promote yeast growth upon air exposure after a sufficient length of time. Chitosan oligomers of three different states viz. completely dried, freshly prepared and highly viscous form, were prepared to compare their in-vitro antifungal activities against three brown-rot fungi, two sapstain and one mould fungus using agar nutrient medium. Additionally, a mixture of chitosan oligomers and boric acid was used for wood treatment. The nutrient medium bioassay results show that all states of chitosan oligomers inhibited the growth of tested basidiomycetes fungi, but not sapstain and mould fungi. Subsequently, wood decay results confirm antifungal activity of chitosan oligomers plus boron against basidiomycetes, but highlighted their leachability upon water exposure. 相似文献
998.
Product quality in mechanical assemblies is determined by controlling the propagation of manufacturing variations as the structure is built. This paper focuses on straight-build assembly and uses a probabilistic approach to analyse the influence of component variation on the eccentricity of the build. Connective models are used to predict assembly variations arising from individual component variations, and a probabilistic approach is used to calculate the probability density function (pdf) for the eccentricity of the build. The probabilistic approach considers three different straight-build scenarios: (i) direct build; (ii) best build; and (iii) worst build, for two-dimensional “axi-symmetric” assemblies. The probabilistic approach is much more efficient than Monte Carlo simulation. The paper also uses numerical examples to investigate the accuracy of the probabilistic approach in comparison to Monte Carlo simulation. 相似文献
999.
S. Nazir N. Ikram S.A. Siddiqi Y. Saeed A. Shaukat Ali Hussain Reshak 《Current Opinion in Solid State & Materials Science》2010,14(1):1-6
We employ the full-potential linearized augmented plane wave plus local orbital (FP-L/APW + lo) method based on spin-polarized density functional theory (DFT) in order to investigate the structural, electronic and magnetic properties of ordered dilute ferromagnetic semiconductors Zn1?xCrxS and Cd1?xCrxS (x = 0.25) in the zinc blende (B3) phase. For the exchange-correlation functional, the generalized gradient approximation GGA (Wu-Cohen 06) has been used. Results of calculated electronic band structures and density of states of these dilute magnetic semiconductors (DMSs) are discussed in terms of the contribution of Cr 3d5 4s1, Zn 3d10 4s2, Cd 4d10 5s2 and S 3s2 3p4 partial density of states. For Cr-based systems without n or p-type doping, the stability of the ferromagnetic spin state versus the antiferromagnetic state is predicted. Band structure and density of states studies show half-metallic ferromagnetic nature for both alloys, Zn1?xCrxS and Cd1?xCrxS. Calculations of the s–d exchange constant N0α and p–d exchange constant N0β clearly indicate the magnetic nature of these compounds. From the calculated total magnetic moments we observe that p–d hybridization reduces the local magnetic moment of Cr from its free space charge value and produces small local magnetic moments on the nonmagnetic Zn, Cd and S sites. The robustness of half-metallicity of Zn1?xCrxS and Cd1?xCrxS as a function of lattice constant is also discussed. 相似文献
1000.