Showing papers by "University of Bahrain published in 2003"

A fuzzy clustering neural network architecture for multifunction upper-limb prosthesis

Abstract: Accurate and computationally efficient means of classifying surface myoelectric signals has been the subject of considerable research effort in recent years. The aim of this paper is to classify myoelectric signals using new fuzzy clustering neural network (NN) architectures to control multifunction prostheses. This paper presents a comparative study of the classification accuracy of myoelectric signals using multilayered perceptron NN using back-propagation, conic section function NN, and new fuzzy clustering NNs (FCNNs). The myoelectric signals considered are used in classifying six upper-limb movements: elbow flexion, elbow extension, wrist pronation and wrist supination, grasp, and resting. The results suggest that FCNN can generalize better than other NN algorithms and help the user learn better and faster. This method has the potential of being very efficient in real-time applications.

Optical characterization of thermally evaporated thin CdO films

Abstract: Cadmium Oxide films have been prepared by vacuum evaporation method on a glass substrate at room temperature. Detailed structural, optical, and electrical properties of the films are presented at different annealing temperatures. The crystal structure of the samples was studied by X- ray diffraction. The spectral absorption coefficient of the CdO film at the fundamental absorption region (450-650nm) was determined using the spectral data of transmittance. The direct and indirect band gap energies were determined and found to be 2.33 eV and 1.95 eV respectively. The third order optical nonlinearities χ(3) of CdO films has been measured used the z-can technique. The real and imaginary parts of χ(3) have been measured at 514 nm and found to be 1.7x10-3 esu and 3.0x10-3 esu, respectively. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Corporate budget planning, control and performance evaluation in Bahrain

Abstract: Examines budget planning; implementation and performance evaluation practices by utilizing a questionnaire survey of 54 medium and large sized companies located in Bahrain. Most of the companies prepare long‐range plans and operating budgets, and they follow a definite budget procedure and implementation methodology. Uses budget variances to measure a manager’s ability, for timely recognition of problems, and to improve the next period’s budget. While both the listed and non‐listed companies have reported many similar budget practices, the main differences were specific purposes served by budgets, degree of budget participation, periodicity of variance reporting, and purposes and authority to evaluate budget variance reports. In certain cases, firm size influences budgeting practices. Contributes toward filling a gap in the literature on the use of budgets as a planning and control tool in developing countries. Most prior studies were mainly confined to advanced countries. The study findings suggest the need for research on attitudes held by the budgetees towards the use of budget variances in the context of advanced management accounting techniques.

Financial reporting on the internet: Empirical evidence from Bahrain and Kuwait

Abstract: In this paper, we examine the factors that are likely to explain the use of the internet as a vehicle for voluntary financial reporting by companies in Bahrain and Kuwait. A total of 75 companies (Kuwait 42 and Bahrain 33) were investigated to find out if they had websites and presented their financial statements on the internet. For Kuwait, 47.6% and for Bahrain 48.5% of sample companies had their own websites. Six variables were tested to examine their influence on the financial reporting by companies on the internet. A discriminant analysis was performed on the data and the results indicated that size (log of total assets) and industry were the main factors which influenced the financial reporting practices of companies on the internet. These results are in line with prior evidence. There is some indication that risk may also contribute to some extent in such decision. Perceptions of advantages and problems in using this new technology for financial reporting were also examined. It appears that the usage of this technology is still limited and slow in this part of the world, perhaps because of cultural dimensions and constraints.

Dynamic vehicular delay comparison between a police-controlled roundabout and a traffic signal

Abstract: Effects of queues on motorists during rush hours are severe at intersections controlled by roundabouts. Traffic police are frequently used in order to optimize the traffic flow and to control queue length at such intersections. However, the question as to how efficient such system is, compared with traffic signal, is not clear from the dynamic delay point of view. In this study a criterion is being developed based on vehicular delays as the motorist join the queues and cross the stop-line. The adopted method avoids oversimplification of reality and prevents unrealistic assumptions. The data required for the study were mainly collected through video filming technique. The results, for a given set of geometric and traffic characteristics, indicate that both a police-controlled roundabout and a traffic signal act in a similar manner in terms of vehicular delay at a certain critical value. This critical value is considered to be the point of intersection between the curves representing traffic signal and roundabout on a delay-space diagram for the vehicles as they join the tail end of the queue until they cross the stop-line. Beyond the critical value, the effect of delays and buildup of queues at roundabouts will be excessive, compared to traffic signals. Before the critical value the delays at traffic signals are quite high compared to roundabouts. The study will assist the concerned authorities to operate the existing conditions, particularly the roundabouts, more efficiently. It will also be beneficial for the traffic planners and policy makers in making judicious decisions regarding control type at intersections.

Poole-Frenkel electrical conduction in europium oxide films deposited on Si(100)

Abstract: Thin Eu2O3 films were prepared on Si (P) substrates to form MOS devices. The oxide crystal structure was determined by X-ray diffraction (XRD). The electrical transport properties of the devices with amorphous and crystalline Eu oxide were investigated. The current-voltage and current-temperature characteristics suggest a Poole-Frenkel (PF) type mechanism of carrier transport through the device when the applied field is more than 105 V/cm. A deviation from PF leakage current course was found and attributed to the current carrier trapping. We have also observed that, the dielectric spectra of MOS structure are different when the insulator is an amorphous or crystalline thin film. From which we calculate the relaxation time (τ) of the interface (insulator/semiconductor) dipoles. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Dynamics of an Elastic Cable Carrying a Moving Mass Particle

Abstract: The dynamic behavior of an elastic catenary cable due to a moving mass alongits length is investigated. The equations of motions are derived using theHamilton's principle for general supports that include the horizontal andinclined cables with small and large sags and for variable velocity of themoving mass. Those equations of motions are in general nonlinear partialdifferential equations due to the initial curvature of the cable. Theequations are also complex due to the presence of three different types ofaccelerations of the moving mass. Those are the normal, Coriolis andcentrifugal accelerations. Therefore, we used the Galerkin procedure withsine function (Fourier representation) and anti-derivative functions of thecompactly supported wavelets as trial basis and used direct integrationmethods to integrate the discretized equations of motions. Newton–Raphsonmethod is used for iterations. Several examples are studied and the resultsas obtained by Fourier and wavelet representations are compared. Because ofthe localization feature, wavelets are proven to minimize the spuriousoscillations specially those appearing in the cable tension.

Investigation of thermal performance of a ground coupled heat pump system with a cylindrical energy storage tank

Abstract: An analytical and computational model for a solar assisted heat pump heating system with an underground seasonal cylindrical storage tank is developed. The heating system consists of flat plate solar collectors, an underground cylindrical storage tank, a heat pump and a house to be heated during winter season. Analytical solution of transient field problem outside the storage tank is obtained by the application of complex finite Fourier transform and finite integral transform techniques. Three expressions for the heat pump, space heat requirement during the winter season and available solar energy are coupled with the solution of the transient temperature field problem. The analytical solution presented can be utilized to determine the annual variation of water temperature in the cylindrical store, transient earth temperature field surrounding the store and annual periodic performance of the heating system. A computer simulation program is developed to evaluate the annual periodic water and earth temperatures and system performance parameters based on the analytical solution. Copyright © 2003 John Wiley & Sons, Ltd.

Hydrodynamic studies in both bi-dimensional and three-dimensional bubble columns with a single sparger

Abstract: Gas holdup in highly viscous fluid in two-phase bubble column with a single sparger operated continuously with respect to the gas flow and batch wise with respect to the liquid was investigated using bed expansion technique. Two- and three-dimensional columns of the same effective cross-sectional area were investigated. Liquid viscosity varied between 0.063 and 0.320 Pa s, static bed heights between 0.12 and 0.60 m, surface tension between 0.0248 and 0.035 N m −1 and density between 906 and 928 kg m −3 . Columns were injected with air at superficial gas velocities between 0.0018 and 0.290 m s −1 . A single nozzle sparger of 0.01 m diameter was used. The behavior of bubbles in two-dimensional bubble column was found to fall into the bubble flow regime, whereas the behavior in three-dimensional column was found to fall into the churn turbulent regime. Two correlations for gas holdup in the two- and three-dimensional bubble columns were proposed and compared with correlations listed in the literature.

Structural and optical properties of evaporated Zn oxide, Ti oxide and Zn-Ti oxide films

Abstract: Zn oxide, Ti oxide and Zn-Ti oxide thin films were prepared by vacuum evaporation. Their structural and optical properties have been obtained by X-ray diffractometry (XRD), the energy-dispersive X-ray fluorescence (EDXRF) method and spectrophotometry. The EDXRF method was used to study the stoichiometry of the deposited Zn-Ti oxide films. The XRD patterns show that the prepared ZnO and Zn-Ti oxide films were polycrystalline, while Ti oxide films were amorphous. Spectroscopic optical constants n(λ) and k(λ) as well as the energy gap Eg were evaluated from spectrophotometry in the interband transition energy region. It was discovered that ZnO–TiO thin films remain transparent in a shorter wavelength range than the ZnO thin films, resulting from the slight increase of their band gap. It was found that n, k and transmittance values for the mixed-oxide film vary smoothly between the values of the pure constituent oxides in the fundamental energy gap region.

Fuzzy logic control of a pH neutralization process

Abstract: In this paper, fuzzy logic control of a pH neutralization process is attempted. The pH neutralization process is a classic example of a highly nonlinear system. For nonlinear systems, fuzzy logic control provides a better alternative to the classical proportional plus integral (PI) controller. Both the controllers namely the PI controller and fuzzy logic controller (FLC) are designed for a simulated pH neutralization process. It is shown that the FLC is able to control the pH neutralization process better. The simulation is performed in the MATLAB environment using Simulink and Fuzzy Logic Toolbox.

Acoustic waves in a liquid with a bubble screen

Abstract: In this work, certain peculiarities of the dynamics of pressure waves in a liquid containing bubbles are studied. The specification of a model of bubbly liquids with regard to acoustic damping of the bubbles is considered. Our theoretical results are compared with experimental ones.

Wavelet-Galerkin Method for Free Vibrations of Elastic Cable

Abstract: The wavelet-Galerkin method is applied to study the free vibration of a horizontally suspended catenary cable. Antiderivatives of the Daubechies compactly supported wavelets have been used with multilevel representations. Comparison between wavelet and Fourier methods is presented for natural frequencies, mode shapes, and dynamic tension of the cable. Both methods showed that they are converging fast in obtaining the natural frequencies and mode shapes. However, as the dynamic tension is obtained, the Fourier solution shows many oscillations and the existence of the Gibbs phenomenon at the cable supports, whereas, these oscillations do not appear in the wavelet solutions. Comparison is also made with the linear theory of cable vibration. Due to the inclusion of the inertia term of the longitudinal component in our solution, new modes have been found. Those modes are reverting but swapping modes in which the longitudinal displacement component is larger than the transverse displacement component.

Information-induced strategic alignment: toward a semiological analysis

Abstract: The concept of strategic alignment between organizational policies for business and information systems (IS) has not been defined previously in informational terms. In this paper, we define informational aspects of organizational behavior in three semiological dimensions: pragmatics, semantics and syntactics. We also introduce dynamics as a fourth dimension to address time-related changes. We demonstrate the importance of these ideas in the analysis of strategic alignment by taking recent examples to show how informational attributes are often implicitly discussed in the literature. We believe that the precise definition of the informational aspects of alignment is a necessary prerequisite for the advancement of understanding in this important area.

Spectra of a weakly driven two-level atom in an off-resonant squeezed vacuum

Abstract: We have derived analytical expressions for the absorption-dispersion spectra as well as the steady state fluorescence spectrum of a weakly excited single 2-level atom in a broadband squeezed vacuum. The atomic transition frequency and the central frequency of both the squeezed vacuum field and the driving field are assumed different. The absorption-dispersion and resonance fluorescence spectra are found to be very much dependent on the atomic as well as squeezed vacuum detuning and can lead to the situation of negative group velocities. Also, the resonance fluorescence spectrum is sensitive to the relative phase of squeezed vacuum and the driving field in the presence of finite detuning of the squeezed vacuum field.

Influence of the cross–cultural environment on the perception of aging and adult development in the developing world: A study of Bahrain, Brazil and Indonesia

Abstract: The present study examined the perceived characteristics associated with the different stages of adulthood in developing societies. Respondents from three societies, Bahrain, Brazil and Indonesia, identified those characteristics that are typical of the early, middle and late adulthood stages in their respective societies. Although developing nations, these societies differed in their levels of modernization or on the UN human development index score and respondents identified characteristics that were both common and different. On the whole, the characteristics identified reflected the influence of a cross–cultural environment (which included the global, developed and developing dimensions) on the perception of aging and adult development in developing societies.

Profile of the climate change in the Kingdom of Bahrain

Abstract: Long-term meteorological data from the Kingdom of Bahrain (1902 to 2001), along with other data from the Sultanate of Oman and the Kingdom of Saudi Arabia, were used to study the profile and the characteristics of the climate changes in the Kingdom of Bahrain. This article illustrates the possible effects of several factors, such as greenhouse gases (GHG), sunspot number, cosmic ray flux, planet conjunctions, the Earth's magnetic field, as well as volcanic eruption, on the profile of the climate change. In general, we found that the temperature variations, to a certain extent, are associated with the cyclic variations in sunspot number (the 11-year cycle), which in turn affect the pattern of the cosmic ray flux due to the distortion of the interplanetary magnetic field. The latter is believed to influence cloud formation. In addition, the discrepancy in the climate change pattern in Bahrain was also attributed to the combined effect of the high local level of CO2 emissions as well as that of other cooling gases in the region. Copyright © 2003 John Wiley & Sons, Ltd.

Squeezing evolution with non-dissipative SU(1,1) systems

Abstract: We investigate the squeezed regions in the phase plane for non-dissipative dynamical systems controlled by SU(1,1) Lie algebra. We analyse such a study for the two SU(1,1) generalized coherent states, namely the Perelomov coherent state and the Barut–Girardello coherent state.

New better than renewal-used classes of life distributions

Abstract: The concept of stochastic dominance in economics is used to compare the conditional life distribution of a used device that has lived until time t/spl ges/0 and its life distributions at time t=0. This comparison gives two classes of life distributions namely, the NBRU class of life distribution and its dual. Relations of these classes to existing criteria of aging and some of their closure properties under reliability operations are studied. The preservation of these aging properties for the survival probability under the homogeneous shock model process are investigated.