We study the temporal evolution of the market efficiency in the stock markets using the complexity, entropy density, standard deviation, autocorrelation function, and probability distribution of the log return for Standard and Poor’s 500 (S&P 500), Nikkei stock average index, and Korean composition stock price index (KOSPI). Based on a microscopic spin model, we also find that these statistical...

In the introductory lectures, we have discussed Markowitz’ theory of mean-variance optimization (MVO) for the selection of portfolios of securities (or asset classes) in a manner that trades off the expected returns and the perceived risk of potential portfolios. Consider assets S1, S2, . . . , Sn (n ≥ 2) with random returns. Let μi and σi denote the expected return and the standard deviation o...

This paper proposes simple methods for staffing a single-class call center with uncertain arrival rate and uncertain staffing due to employee absenteeism. The arrival rate and the proportion of servers present are treated as random variables. The basic model is a multi-server queue with customer abandonment, allowing non-exponential service-time and time-to-abandon distributions. The goal is to...

BACKGROUND In systematic reviews and meta-analysis, researchers often pool the results of the sample mean and standard deviation from a set of similar clinical trials. A number of the trials, however, reported the study using the median, the minimum and maximum values, and/or the first and third quartiles. Hence, in order to combine results, one may have to estimate the sample mean and standard...

This paper reports on the factors affecting occupational composition of Pakistani workers upon their return from Middle East employment locations as determined by using the 1986 ILO/ARTEP Survey of Return Migrant Households. Three issues related to post-migration occupation change of return migrants were explored: 1) the comparison of occupational composition in the pre-migration phase with th...

The Olivetti Research Laboratory has developed an experimental system based on intelligent peripherals connected directly to an ATM network. As well as multimedia modules (e.g. audio and video) the system also includes a directly connected RAID-3 storage server called the “Disc Brick”. This paper describes the architecture of the Disc Brick, and discusses some of the hardware and software issue...