CHRIS P. TSOKOS and A.N.V. RAO
1 INTRODUCTION Consider the stochastic control system of the form
Nalina Suresh, A.N.V. Rao and A.J.G. Babu
Most of the existing software reliability models assume time between failures to follow an exponential distribution. Develops a reliability growth model based on non‐homogeneous…
Abstract
Most of the existing software reliability models assume time between failures to follow an exponential distribution. Develops a reliability growth model based on non‐homogeneous Poisson process with intensity function given by the power law, to predict the reliability of a software. Several authors have suggested the use of the non‐homogeneous Poisson process to assess the reliability growth of software and to predict their failure behaviour. Inference procedures considered by these authors have been Bayesian in nature. Uses an unbiased estimate of the failure rate for prediction. Compares the performance of this model with Bayes empirical‐Bayes models and a time series model. The model developed is realistic, easy to use, and gives a better prediction of reliability of a software.
Details
Keywords
Arun Jyoti Nath and Ashesh Kumar Das
The present study seeks to evaluate the role of village bamboo management in the rural landscape of North East India in global climate change mitigation.
Abstract
Purpose
The present study seeks to evaluate the role of village bamboo management in the rural landscape of North East India in global climate change mitigation.
Design/methodology/approach
A set of 100 home gardens and 40 bamboo groves were selected from Irongmara and Dargakona village, in Cachar district, Assam, North East India through random sampling. Sampling was done mostly for smallholders. Culm growth, carbon storage, carbon sequestration and carbon in litter floor mass and soil of bamboo growing areas in homegarden was explored from 2003‐2007.
Findings
Culm growth extension revealed the brief periodicity of culm growth in a single growth period. Of the total carbon storage soil contributed 84.6 per cent of the total (50.1 Mg ha−1) followed by carbon in above ground vegetation 15 per cent (9 Mg ha−1) and carbon in litter floor mass 0.4 per cent (0.2 Mg ha−1).
Practical implications
Bamboo plantation development and its management in home gardens has social, ecological and economical benefits for the rural life in North East India and its promotion can become an effective choice for climate change mitigation strategy.
Originality/value
Bamboo forms an important component in the traditional home garden system of North East India where the practice of bamboo cultivation and management provides an important sink for CO2. Village bamboos play an important role in local economics, societies and environments and, considering its potential to mitigate global climate change, the authors recommend the promotion of bamboo in agroforestry expanding practices and rehabilitation of degraded lands. Management of village bamboos in rural landscape is highlighted in context to environmental sustainability and as a sink measure under the Clean Development Mechanism (CDM) of Kyoto Protocol.
Details
Keywords
Kavitha Rajagopal, George T Oommen, P. Kuttinarayanan, Sisilamma George and K.M. SyamMohan
This study aims to assess the effects of calcium chloride marination on buffalo meat tenderness, instrumental color and palatability traits and to compare the effects with that of…
Abstract
Purpose
This study aims to assess the effects of calcium chloride marination on buffalo meat tenderness, instrumental color and palatability traits and to compare the effects with that of aging, so as to suggest a cost-effective tenderizing method to meat retailers.
Design/methodology/approach
Buffalo longissimus thoracis (LT) steaks were marinated post-rigor with 200-mM (5 per cent w/w) calcium chloride solution and were subjected to aging at 2-4°C for eight days. The pH, water holding capacity (WHC), cooking loss, color, myofibrillar fragmentation index, Warner–Bratzler shear force and sensory quality attributes were assessed at 1, 2, 4, 6 and 8 days post-mortem. The values were then compared with those of control steaks kept at the same storage conditions.
Findings
Marination was not found to affect pH, WHC, cooking loss or color as compared to the control steaks. Tenderness was found to be improved in marinated steaks by 53.44 per cent as against 35.59 per cent in those that aged without marination. The sensory panel evaluation showed that marinated steaks significantly improved (p < 0.01) in the scores for the different attributes, and no flavor problems or alterations in cooked color were noticed.
Research limitations/implications
The animals used in this study fall in the age group of four-eight years with one of them being four years old and the rest above the age of six years. Given the fact that, age-related increase in pyridinoline content of intramuscular collagen and cross-link formation influenced by sex can contribute to the toughness of meat in spent animals (Bosselmann et al., 1995), the variation in age of the animals under study could be regarded as a limitation of the study. But apart from one animal, all of them were more than six years old, forming more or less uniform samples.
Originality/value
This research is of value to the meat industry or retailers. The post-rigor marination of buffalo LT steaks with 200-mM CaCl2 (5 per cent w/w) appears to be a promising measure from the view of practicability. The relative ease of operation makes it superior to other successful techniques in reducing toughness, such as electrical stimulation.
Details
Keywords
Alexei V. Matveev and Richard G. Milter
Managers working in multinational companies carry out their organizational goals through multicultural teams. Performance of multicultural teams can be examined from an…
Abstract
Managers working in multinational companies carry out their organizational goals through multicultural teams. Performance of multicultural teams can be examined from an intercultural communication perspective. Executives, managers, management consultants, and educators interested in improving multicultural team performance need to know about intercultural competence and how it affects team performance. This article provides a working definition of high‐performance multicultural teams and outlines the challenges multicultural teams face. These definitions along with extensive interview data and detailed self‐reports of American and Russian managers working in multicultural teams emphasize the high importance of intercultural competence in improving the performance of these teams. This article also serves to highlight the characteristics of high‐performance multicultural teams, the common challenges of multicultural teams, and the sources of these challenges.
Details
Keywords
Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the…
Abstract
Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the theoretical as well as practical points of view. The range of applications of FEMs in this area is wide and cannot be presented in a single paper; therefore aims to give the reader an encyclopaedic view on the subject. The bibliography at the end of the paper contains 2,025 references to papers, conference proceedings and theses/dissertations dealing with the analysis of beams, columns, rods, bars, cables, discs, blades, shafts, membranes, plates and shells that were published in 1992‐1995.
Details
Keywords
Shashank Rebelli and Bheema Rao Nistala
This paper aims to model the coupled on-chip Copper (Cu) interconnects by using the multiresolution time-domain (MRTD) method.
Abstract
Purpose
This paper aims to model the coupled on-chip Copper (Cu) interconnects by using the multiresolution time-domain (MRTD) method.
Design/methodology/approach
The proposed model is a wavelet-based numerical method for analyzing signal integrity and propagation delay of coupled on-chip interconnects. Moreover, the dependency of crosstalk noise and delay on coupling parasitics (L12, C12) are analyzed.
Findings
The proposed MRTD method captures the behaviour of propagation delay and peak crosstalk noise on victim line against coupling parasitics, which is in close agreement with that of H simulation program with integrated circuit emphasis (HSPICE). The average error for the proposed model is less than 1 per cent with respect to HSPICE for the estimation of peak crosstalk noise voltage.
Practical implications
Simulations are performed using HSPICE and compared with those performed using the proposed MRTD method for global interconnect length with 130-nm technology, where the computations of the proposed model are carried out using Matlab.
Originality/value
The MRTD method with its unique features is tailored for modelling interconnects. To build further credence to this and its profound existence in the latest state-of-art works, simulations of crosstalk noise and propagation delay, for coupled Cu interconnect lines, using MRTD and finite-difference time-domain (FDTD) are executed. The results illustrated the dominance of MRTD method over FDTD in terms of accuracy.
Details
Keywords
Balancing accuracy and efficiency is an important evaluation index of response surface method. The purpose of this paper is to propose an adaptive order response surface method…
Abstract
Purpose
Balancing accuracy and efficiency is an important evaluation index of response surface method. The purpose of this paper is to propose an adaptive order response surface method (AORSM) based on univariate decomposition model (UDM).
Design/methodology/approach
First, the nonlinearity of the univariate function can be judged by evaluating the goodness of fit and the error of curve fit rationally. Second, combining UDM with the order analysis of separate component polynomial, an easy-to-implement AORSM is proposed. Finally, several examples involving mathematical functions and structural engineering problems are studied in detail.
Findings
With the proposed AORSM, the orders of component functions in the original response surface can be determined adaptively and the results of those cases in this paper indicate that the proposed method performs good accuracy, efficiency and robustness.
Research limitations/implications
Because just the cases with single failure mode and single MPP are studied in this paper, the application in multi-failure mode and multi-MPP cases need to be investigated in the coming work.
Originality/value
The nonlinearity of the univariate in the response surface can be determined adaptively and the undetermined coefficients of each component function are obtained separately, which reduces the computation dramatically.
Details
Keywords
An unconditionally positive definite finite difference scheme termed as UPFD has been derived to approximate a linear advection-diffusion-reaction equation which models…
Abstract
Purpose
An unconditionally positive definite finite difference scheme termed as UPFD has been derived to approximate a linear advection-diffusion-reaction equation which models exponential travelling waves and the coefficients of advection, diffusion and reactive terms have been chosen as one (Chen-Charpentier and Kojouharov, 2013). In this work, the author tests UPFD scheme under some other different regimes of advection, diffusion and reaction. The author considers the case when the coefficient of advection, diffusion and reaction are all equal to one and also cases under which advection or diffusion or reaction is more important. Some errors such as L1 error, dispersion, dissipation errors and relative errors are tabulated. Moreover, the author compares some spectral properties of the method under different regimes. The author obtains the variation of the following quantities with respect to the phase angle: modulus of exact amplification factor, modulus of amplification factor of the scheme and relative phase error.
Design/methodology/approach
Difficulties can arise in stability analysis. It is important to have a full understanding of whether the conditions obtained for stability are sufficient, necessary or necessary and sufficient. The advection-diffusion-reaction is quite similar to the advection-diffusion equation, it has an extra reaction term and therefore obtaining stability of numerical methods discretizing advection-diffusion-reaction equation is not easy as is the case with numerical methods discretizing advection-diffusion equations. To avoid difficulty involved with obtaining region of stability, the author shall consider unconditionally stable finite difference schemes discretizing advection-diffusion-reaction equations.
Findings
The UPFD scheme is unconditionally stable but not unconditionally consistent. The scheme was tested on an advection-diffusion-reaction equation which models exponential travelling waves, and the author computed various errors such as L1 error, dispersion and dissipation errors, relative errors under some different regimes of advection, diffusion and reaction. The scheme works best for very small values of k as k → 0 (for instance, k = 0.00025, 0.0005) and performs satisfactorily at other values of k such as 0.001 for two regimes; a = 1, D = 1, κ = 1 and a = 1, D = 1, κ = 5. When a = 5, D = 1, κ = 1, the scheme performs quite well at k = 0.00025 and satisfactorily at k = 0.0005 but is not efficient at larger values of k. For the diffusive case (a = 1, D = 5, κ = 1), the scheme does not perform well. In general, the author can conclude that the choice of k is very important, as it affects to a great extent the performance of the method.
Originality/value
The UPFD scheme is effective to solve advection-diffusion-reaction problems when advection or reactive regime is dominant and for the case, a = 1, D = 1, κ = 1, especially at low values of k. Moreover, the magnitude of the dispersion and dissipation errors using UPFD are of the same order for all the four regimes considered as seen from Tables 1 to 4. This indicates that if the author is to optimize the temporal step size at a given value of the spatial step size, the optimization function must consist of both the AFM and RPE. Some related work on optimization can be seen in Appadu (2013). Higher-order unconditionally stable schemes can be constructed for the regimes for which UPFD is not efficient enough for instance when advection and diffusion are dominant.