Architectural,construction and environmental matters of Bahrain's International Formula 1 Circuit

The Bahrain International Circuit (BIC) is considered as one of the best international racing car track in terms of technical aspects and architectural quality. Two Formula 1 races have been hosted in the Kingdom of Bahrain, in 2004 and 2005, at BIC. The BIC had recently won the award of the best international racing car circuit.     

The Michigan benchmark: towards XML query performance diagnostics

We propose a micro-benchmark for XML data management to aid engineers in designing improved XML processing engines. This benchmark is inherently different from application-level benchmarks, which are designed to help users choose between alternative products. We primarily attempt to capture the rich variety of data structures and distributions possible in XML, and to isolate their effects, without imitating any particular application. The benchmark specifies a single data set against which carefully specified queries can be used to evaluate system performance for XML data with various characteristics.     

Online droplet diameter measurements to improve the crude oil dehydration process

Emulsion droplet size is information of paramount importance in the design and evaluation of oil–water separators. This paper describes the application of a technique for in situ determination of water droplet diameter distribution (DDD) in actual production scenarios. We discuss the DDD and water content measurements in emulsions obtained during normal operation and plant upsets including variations of the demulsifier chemical dosage or tripping of the electrostatic coalescer grids inside a large dehydrator vessel operated on a crude oil production field in Saudi Arabia. It is demonstrated that DDD data can provide a detailed understanding of the oil–water separation phenomena occurring inside the dehydrator vessel, which helped in planning process recovery strategies in the event of a plant upset.     

An adaptive step-down procedure for fault variable identification

In a process with a large number of process variables (high-dimensional process), identifying which variables cause an out-of-control signal is a challenging issue for quality engineers. In this paper, we propose an adaptive step-down procedure using conditional T² statistic for fault variable identification. While existing procedures focus on selecting variables that have strong evidence of a change, the proposed step-down procedure selects a variable having the weakest evidence of a change at each step based on the variables that are selected in previous steps. The information of selected unchanged variables is effectively utilised in obtaining a powerful conditional T² test statistic for identifying the changed elements of the mean vector. The proposed procedure is designed to utilise the correlation information between fault and non-fault variables for the efficient fault variables identification. Further, the simulation results show that the proposed procedure has the better diagnostic performance compared with existing methods in terms of fault variable identification and computational complexity, especially when the number of the variables is high and the number of fault variables is small.     

Multivariate statistical process control charts based on the approximate sequential χ2 test

Similar to the univariate CUSUM chart, a multivariate CUSUM (MCUSUM) chart can be designed to detect a particular size of the mean shift optimally based on the scheme of a sequential likelihood ratio test for the noncentrality parameter. However, in multivariate case, the probability ratio of a sequential test is intractable mathematically and the test statistic based on the ratio does not have a closed form expression which makes it impractical for real application. We drive an approximate log-likelihood ratio and propose a multivariate statistical process control chart based on a sequential χ² test to detect a change in the noncentrality parameter. The statistical properties of the proposed test statistic are explored. The average runs length (ARL) performance of the proposed charts is compared with other MCUSUM charts for process mean monitoring. The experimental results reveal that the proposed charts achieve superior, both zero-state and steady-state, ARL performance over a wide range of mean shifts, especially when the dimension of measurements is large.     

Revisiting the accessibility of Saudi Arabia government websites

Universal Access in the Information Society - With the significant inclusion of the Internet in nearly all aspects of our daily lives, achieving accessible e-government services that enable...     

The accessibility of Saudi Arabia government Web sites: an exploratory study

This study is intended to provide an exploratory evaluation of Saudi Arabia government Web sites based on the Web Accessibility Guidelines 2.0 provided by the W3C. The results indicate that the Saudi government Web sites have made many of the accessibility mistakes as predicted. In the light of the study findings, this paper will present some recommendations for improving Saudi government Web sites, as well as discuss future implications.     

Economic cost models of integrated APC controlled SPC charts

In this paper, an economic cost model is proposed for processes integrating both automatic process control (APC) and statistical process control (SPC) for quality monitoring and control. Both the special cause and common cause variations are reduced by applying integrated APC and SPC. Traditionally, the integrated processes using APC and SPC are evaluated by the average run length (ARL). However, ARL may not be appropriate as a measurement of the economic design since it does not take into consideration the run length variation. Also, there are few studies that compare the cost models of such an integrated control system and the effect of cost parameters using different APC controllers. Therefore, we develop an economic cost model using non-homogenous Poisson process to describe the occurrence of an APC adjustment and develop a long run expected cost to investigate the use of different controllers in such integrated systems. Numerical examples are presented to demonstrate the applicability of the proposed model.