Comparison of genomic sequences using the Hamming distance

The paper considers the problem of homogeneity among groups by comparison of genomic sequences. Some alternative procedures that attach less emphasis on the likelihood approach, and more on alternative measures that deal with similar homogeneity problems are considered here. On this approach, a one-sided hypothesis test is considered and the classical ANOVA decomposition can be directly adapted to sample measures based on the Hamming distance, without necessarily going through their second moments. Some results of U-statistics theory will be useful for the decomposition of the test statistic and to find its asymptotic distribution. An application of this test with real data is shown and the p-value of the test statistic is found via bootstrap resampling.     

Joint confidence regions in the multivariate calibration problem

Consider a vector valued response variable related to a vector valued explanatory variable through a normal multivariate linear model. The multivariate calibration problem deals with statistical inference on unknown values of the explanatory variable. The problem addressed is the construction of joint confidence regions for several unknown values of the explanatory variable. The problem is investigated when the variance covariance matrix is a scalar multiple of the identity matrix and also when it is a completely unknown positive definite matrix. The problem is solved in only two cases: (i) the response and explanatory variables have the same dimensions, and (ii) the explanatory variable is a scalar. In the former case, exact joint confidence regions are derived based on a natural pivot statistic. In the latter case, the joint confidence regions are only conservative. Computational aspects and the practical implementation of the confidence regions are discussed and illustrated using an example.     

A Social Decision Analysis of the Earthquake Safety Problem: The Case of Existing Los Angeles Buildings

In this paper we propose a framework for conducting a decision analysis for a societal problem such as earthquake safety. The application deals with the formulation and evaluation of alternative policies for the seismic safety problem faced by the city of Los Angeles with regard to its old masonry buildings. A social decision analysis compares the costs and benefits of the alternative policies from the viewpoints of the impacted constituents. The emphasis is on identifying acceptable policy that considers the interests of the impacted constituents and provides incentives for their cooperation. Alternatives ranging from strict regulation to free market are examined. In order to evaluate the trade-offs between additional cost and savings in lives, a direct willingness-to-pay and an economic approach, based on property value differential, are used. Recommendations range from strict regulation for the residential and critical buildings (schools, hospitals, fire stations, etc.) to simply informing the occupants (in the case of commercial and industrial buildings) of the risks involved.     

Book reviews

L. Keeble and B.D. Loader (eds) Community Informatics. Shaping Computer-mediated Social Relations (London: Routledge, 2001), pp. 388, ISBN 0-415-23112-4 (pbk) £18.99.

H. Dreyfus, On the Internet: Thinking in Action (London: Routledge, 2001), pp. 136, ISBN 0-415228-077 (pbk).

D. Miller and D. Slater, The Internet: An Ethnographic Approach (Oxford and New York: Berg, 2000), pp. 217, ISBN 1-8S973-389-1 (pbk) £14.99.     

Assessment of physical exposures and comparison of exposure definitions in a repetitive sawmill occupation: trim-saw operator

This paper describes the physical exposures required to perform a sawmill job associated with a high incidence of upper extremity musculoskeletal injury. Exposure variables are described by multiple posture, exertion and frequency definitions and the comparability of those definitions are examined. Effective industrial prevention efforts require an accurate assessment of risk. Surface electromyography and electrogoniometry were used to quantify the physical exposures of 29 trim-saw operators in four sawmill facilities. Average wrist ranges of motion of 32, 57 and 58 degrees in wrist radial/ulnar deviation, flexion/extension and pronation/supination respectively were required to perform the job. Defining wrist range of motion by the peak postures observed versus those required to perform the primary task resulted in significantly different ranges of motion (p<0.05). Job performance required an average of 33% of maximum voluntary contraction. Repetitions per day ranged from 3,549 to 14,460. Percentage of maximum voluntary contraction was not associated with psychophysical measures of exertion.     

Bayes estimation for exponential distributions with common location parameter and applications to multi-state reliability models

This paper considers the estimation of the stress–strength reliability of a multi-state component or of a multi-state system where its states depend on the ratio of the strength and stress variables through a kernel function. The article presents a Bayesian approach assuming the stress and strength as exponentially distributed with a common location parameter but different scale parameters. We show that the limits of the Bayes estimators of both location and scale parameters under suitable priors are the maximum likelihood estimators as given by Ghosh and Razmpour [15 M. Ghosh and A. Razmpour, Estimation of the common location parameter of several exponentials, Sankhyā, Ser. A 46 (1984), pp. 383–394. [Google Scholar]]. We use the Bayes estimators to determine the multi-state stress–strength reliability of a system having states between 0 and 1. We derive the uniformly minimum variance unbiased estimators of the reliability function. Interval estimation using the bootstrap method is also considered. Under the squared error loss function and linex loss function, risk comparison of the reliability estimators is carried out using extensive simulations.     

Moment identity for discrete random variable and its applications

In this paper, we obtain a moment identity applicable to a general class of discrete probability distributions. We then derive the corresponding identities for modified power series, Ord and Katz families. It is noted that the proposed identity has potential applications in different fields.     

Implementing lean sigma in an Indian rotary switches manufacturing organisation

The manufacturing organisations have been witnessing a transformation in the manufacturing paradigm. Lean sigma and six sigma are the two business process improvement strategies widely employed by organisations to enhance their manufacturing performance. To achieve dramatic result in cost, quality and time, best strategies need to be applied to enhance the process performance. Lean sigma and six sigma are two powerful and effective strategies, enabling the organisation to overcome their weakness and for retaining their improvement. Lean sigma combines the variability reduction tools and techniques drawn from six sigma with the waste and non-value added elimination tools and techniques from lean manufacturing to achieve savings in the organisations. This study uses an integrated lean sigma framework to reduce the defects occurring in the final product, thereby contributing savings to the organisation. The proposed framework integrates lean tools within six sigma methodology to enhance the bottom-line results and to win customer loyalty. The implementation of the proposed framework shows dramatic improvement in key metrics and substantial financial savings to be generated by the organisation.