Optimizing channel capacity in a MIMO–PSK wireless rayleigh fading channel

Due to the continual advancement of future generation communication systems, channel capacity is considered to be an important parameter for achieving greater signal strength by means of faster data transmission speed. Usually in multiple input multiple output (MIMO) systems, the diversity technique lessens the propagation speed significantly than the channel capacity. Using MIMO in combination with phase shift keying (PSK) modulation jointly known as MIMO–PSK systems, the present paper focuses on a novel distribution method in order to optimize the channel capacity over a Rayleigh fading channel. First, ergodic channel capacity and distribution capacity in terms of outage capacity is simulated for different MIMO–PSK configurations as well as channel conditions. Later, the channel performance of MIMO–PSK for the novel distribution conditions with antenna correlation effect is evaluated and finally the optimal channel capacity is determined.

     

Finite-time stabilisation for discrete-time T–S fuzzy model system with channel fading and two types of parametric uncertainty

In this paper, the problem of finite-time stabilisation is firstly studied for the Takagi–Sugeno (T–S) fuzzy model system with channel fading and parameter uncertainty. Two theorems are given for the cases with different types of uncertainty. The sufficient conditions in the form of the linear matrix inequalities are derived such that the stabilisation of the closed-loop system is guaranteed. At last, some illustrative examples are employed to demonstrate the efficiency of the results.     

The application of Kolmogorov–Rényi statistics to problems of parameter uncertainty in systems design†

This paper presents a method for dealing with parameter uncertainty in system design which is based on the study of the statistical properties of an ensemble of systems defined by a given structure and by a priori parameter distributions rather than point parameter estimates. It is assumed that the model of the actual system is a random member of the ensemble. The object of the analysis is to design or modify the properties of the ensemble to ensure a high probability of adequate performance of the actual system. The primary statistical function employed is the sample distribution function. This function is used to estimate the true population distribution of a scalar variable chosen to measure the system property of interest. The sample distribution function is constructed from random samples of this figure of merit generated by a suitable digital computer programme. The accuracy of the estimation of the population distribution by the sample distribution is determined by application of statistical results of Kolmogorov and Rényi.     

Double encoding—a technique for reducing storage requirement of text

Many recent advances have been made in data storage and communications media. However, the explosive proliferation of information and the continuous growth of data applications are outgrowing any technological advances in storage devices and communications tools. Data compression offers an attractive approach to alleviate many of the problems associated with data proliferation. In this paper, we present a new double compression scheme for text, program source and documentation files. The first phase of compression is a dictionary-based method that also uses run-length encoding. The second phase of compression is based on utilizing the distributional and correlational properties of the output of the first phase. The technique achieves high degrees of compression and is further enhanced by the hardware assistance that VLSI technology will eventually offer to the realization of data compression techniques.     

The numerical simulation of periodic solutions for a predator–prey system

In this article, the existence and global stability of periodic solutions for a semi-ratio-dependent predator–prey system with Holling IV functional response and time delays are investigated. Using coincidence degree theory and Lyapunov method, sufficient conditions for the existence and global stability of periodic solutions are obtained. A numerical simulation is given to illustrate the results.     

Enhancement of heat transfer in a convergent/divergent channel by using carbon nanotubes in the presence of a Darcy–Forchheimer medium

This article explores the influence of thermal radiation on the flow and heat transfer of single-walled carbon nanotubes over both a convergent and divergent channel. Flow is induced due to a Darcy–Forchheimer medium. Further, the heat transfer mechanism is analyzed in the presence of a thermal radiation process. Guided by some appropriate similarity transformations, the fundamental PDEs are converted into a self-similar system of coupled non-linear ODEs. The findings are obtained with the help of the Runge–Kutta-45-based shooting method. The roles of the Reynolds number, porosity parameter, inertia coefficient parameter, Prandtl number and radiation parameter are presented graphically. Results are displayed and show that the rate of heat transfer is higher in a divergent channel as compared to a convergent channel.

     

The effects of recommendations’ presentation on persuasion and satisfaction in a movie recommender system

The explosive growth of Internet applications and content, during the last decade, has revealed an increasing need for information filtering and recommendation. Most research in the area of recommendation systems has focused on designing and implementing efficient algorithms that provide accurate recommendations. However, the selection of appropriate recommendation content and the presentation of information are equally important in creating successful recommender applications. This paper addresses issues related to the presentation of recommendations in the movies domain. The current work reviews previous research approaches and popular recommender systems, and focuses on user persuasion and satisfaction. In our experiments, we compare different presentation methods in terms of recommendations’ organization in a list (i.e. top N-items list and structured overview) and recommendation modality (i.e. simple text, combination of text and image, and combination of text and video). The most efficient presentation methods, regarding user persuasion and satisfaction, proved to be the “structured overview” and the “text and video” interfaces, while a strong positive correlation was also found between user satisfaction and persuasion in all experimental conditions.     

Performance impact of new product development processes for distinct scenarios under different supplier–manufacturer relationships

Although supplier involvement in new product development (NPD) projects has become increasingly important for strengthening a firm's competitive position, few studies have investigated the impact of changing research and development (R&D) workloads in NPD. According to the level of design-related characteristics including design-related communication and design-related nature, we identify four types of supplier–manufacturer relationships: sequential mode, passive supplier involvement, active supplier involvement, and strategic development. Differing from qualitative and survey-oriented research, this study proposes a system dynamics model for the quantitative exploration of workload impacts on R&D-system equilibrium under different supplier–manufacturer relationships. We justify experimentally the NPD performances of these supplier–manufacturer relationship configurations under workload impacts and provide managerial insights.     

The development of a comprehensive computer program for the study of solid–solid atomic interfaces

This paper describes the construction of a comprehensive computer program to model the structure of the silicon–silicon dioxide (Si–SiO₂) boundary layer of semiconductor devices by combining experimental data from an X-ray storage ring with graphical simulations on a multiprocessor distributed net (or a multiprocessor supercomputer). The term ‘comprehensive’ refers to the program's planned ability to incorporate all stages necessary to translate 2D X-ray spectra to the final 3D atomic image with little or no human intervention. If successful, our efforts will provide materials scientists, engineers, and manufacturers of integrated circuits with an additional tool for understanding interfacial chemistry and thereby suggest new ways to improve the chemical and electronic behavior of their devices.     

A manufacturer–buyer integrated inventory model with stochastic lead times for delivering equal- and/or unequal-sized batches of a lot

Although the subject of manufacturer–buyer integrated inventory management with deterministic lead times has received a lot of attention from researchers, the corresponding problem with stochastic lead times has been given comparatively little consideration. Recently, it has been treated in the case of an exponential distribution of lead times with the lot transferred in equal-sized batches (sub-lots). In this treatment the buyer orders the next batch when his/her stock level falls to a certain reorder point, allowing for shortages and complete backordering. The total cost benefit of solving the problem using an integrated inventory system instead of independent ones had been demonstrated. However, rather than an exponential distribution, a normal distribution of lead times seems to provide a better fit to the problem. Moreover, synchronization of the integrated production flow by generalizing the method of transferring batches of the lot might lead to a lower total cost. Based on these notions, we develop here a manufacturer–buyer integrated inventory model with a normal distribution of lead times for delivering equal- and/or unequal-sized batches of a lot. Then a solution technique to the model and hence a solution algorithm are presented. The potential benefit of the present method is illustrated with solutions of some numerical problems. The sensitivities of the solutions to variations in the parameter values are also studied.     

The Berlin Brain-Computer Interface (BBCI) – towards a new communication channel for online control in gaming applications

The investigation of innovative Human-Computer Interfaces (HCI) provides a challenge for future multimedia research and development. Brain-Computer Interfaces (BCI) exploit the ability of human communication and control bypassing the classical neuromuscular communication channels. In general, BCIs offer a possibility of communication for people with severe neuromuscular disorders, such as Amyotrophic Lateral Sclerosis (ALS) or spinal cord injury. Beyond medical applications, a BCI conjunction with exciting multimedia applications, e.g., a dexterity game, could define a new level of control possibilities also for healthy customers decoding information directly from the user’s brain, as reflected in electroencephalographic (EEG) signals which are recorded non-invasively from user’s scalp. This contribution introduces the Berlin Brain–Computer Interface (BBCI) and presents setups where the user is provided with intuitive control strategies in plausible gaming applications that use biofeedback. Yet at its beginning, BBCI thus adds a new dimension in multimedia research by offering the user an additional and independent communication channel based on brain activity only. First successful experiments already yielded inspiring proofs-of-concept. A diversity of multimedia application models, say computer games, and their specific intuitive control strategies, as well as various Virtual Reality (VR) scenarios are now open for BCI research aiming at a further speed up of user adaptation and increase of learning success and transfer bit rates.

Joint determination of the lot size and number of shipments for a family of integrated vendor–buyer systems considering defective products

In this paper we present two solution procedures to obtain the solution for a family of economic production quantity inventory models for an integrated vendor–buyer system considering that production system generates defective products, in which the number of shipments must be a discrete value and that the lot size can take continuous (case 1) or integer (case 2) values. These solution procedures provide a more realistic approach for solving a family of inventory models. Previous works only derive the optimal lot size considering the number of shipments as a given value or derive both the lot size and the number of shipments considering both decision variables as continuous. The number of shipments takes integer values in real life and thus it must be considered as a discrete variable. This paper revisits and solves previous inventory models considering the variables (lot size and number of shipments) according to their real-life nature.     

The EM algorithm in a distributed computing environment for modelling environmental space–time data

Statistical models for spatio-temporal data are increasingly used in environmetrics, climate change, epidemiology, remote sensing and dynamical risk mapping. Due to the complexity of the relationships among the involved variables and dimensionality of the parameter set to be estimated, techniques for model definition and estimation which can be worked out stepwise are welcome. In this context, hierarchical models are a suitable solution since they make it possible to define the joint dynamics and the full likelihood starting from simpler conditional submodels. Moreover, for a large class of hierarchical models, the maximum likelihood estimation procedure can be simplified using the Expectation–Maximization (EM) algorithm.In this paper, we define the EM algorithm for a rather general three-stage spatio-temporal hierarchical model, which includes also spatio-temporal covariates. In particular, we show that most of the parameters are updated using closed forms and this guarantees stability of the algorithm unlike the classical optimization techniques of the Newton–Raphson type for maximizing the full likelihood function. Moreover, we illustrate how the EM algorithm can be combined with a spatio-temporal parametric bootstrap for evaluating the parameter accuracy through standard errors and non-Gaussian confidence intervals.To do this a new software library in form of a standard R package has been developed. Moreover, realistic simulations on a distributed computing environment allow us to discuss the algorithm properties and performance also in terms of convergence iterations and computing times.     

A design method – based on a shock-response-spectrum analysis – for reducing acoustic noise of a seeking control system in a hard disk drive

A design methodology for reducing seeking noise in a hard disk drive has been developed. This method can optimize the seeking current according to a shock-response-spectrum analysis. It was verified experimentally that this method can reduce the seeking noise by about 4 dBA on average without increasing the seeking time.     

The Design of Human–Machine Interface for Accident Support in Nuclear Power Plants

As feedback from Three Mile Island No. 2, a large amount of human–machine interface (HMI) design has been proposed to support operators during accidents by presenting information on plant status, some of which is implemented in commercial nuclear power plants (NPPs). However, it has not yet been discussed what role HMI should play under conditions where operators must take action as instructed under emergency operating procedure. Regarding this principal issue, an HMI design is proposed together with specific screen images. The advantage of this design is based on the involvement of an ex-operator in NPP in this paper. The participation of users in the design of HMI has been rare. Accordingly the proposed HMI is comprehensive for average operators and is expected to be acceptable for future implementation in commercial NPPs. The effectiveness of the proposed HMI has been examined in a small experiment.     

Using the extension of DEMATEL to integrate hotel service quality perceptions into a cause–effect model in uncertainty

This study proposes an evaluation approach on assessing service quality perceptions based on the fuzzy measure and extension of decision-making trial and evaluation laboratory (EDEMATEL). This research comprises the perception of two study groups, namely, customers and employees, which include 22 evaluation criteria assessed by two groups from the top four English hotels in Taiwan. The human perception on service quality usually involves in imprecision and vagueness. The triangular fuzzy numbers presents the vagueness and subjectivity information, and use defuzzification method to handle the vagueness linguistic information into a crisp value. This study applies fuzzy set theory and EDEMATEL method to evaluate the interrelationships of service quality evaluation criteria and to compromise the group perceptions into a cause and effect model in uncertainty. The proposed approach is an effective method for assessing the group perceptions, and it integrates the different perceptions into a compromised cause and effect model of hotel service quality in uncertainty. The managerial implications are discussed.     

The Context of Information Use in a Hospital as Simultaneous Similarity–Difference Relations

In the light of the developing discourse on the relative merits of ‘hard’ and ‘soft’ approaches to information systems development, we present a case study application of a methodology which attempts to dissolve such dualities. Personal Construct Psychology (PCP) offers, as a unity, the construing person who is both biology and culture. PCP argues that both the world and the person’s construct system are phenomenologically real and that the viability of any particular construct system depends only on its usefulness to the construing person. In this study, we used PCP to explore the organisational context of information use and distribution in a large hospital. We used repertory grids, a PCP technique, to elicit from 16 members of staff their personal construals of information from different sources in the hospital. The results highlight the relationship between meaningful information and meaningfully active relationships, a theme which we discuss in terms of the development of the hospital information system and in terms of the value of PCP in dissolving hard–soft dichotomies.     

The superconvergence of composite Newton–Cotes rules for Hadamard finite-part integral on a circle

We study the general (composite) Newton–Cotes rules for the computation of Hadamard finite-part integral on a circle with the hypersingular kernel and focus on their pointwise superconvergence phenomenon, i.e., when the singular point coincides with some a priori known point, the convergence rate is higher than what is globally possible. We show that the superconvergence rate of the (composite) Newton–Cotes rules occurs at the zeros of a special function and prove the existence of the superconvergence points. The relation between and defined in Wu and Sun (Numer Math 109:143–165, 2008) is established, and the efficient calculation of Cotes coefficients is also discussed. Several numerical examples are provided to validate the theoretical analysis.      

The impact of raindrop drift in a three-dimensional wind field on a radar–gauge rainfall comparison

There are many causes for the discrepancies between weather radar and rain gauges, and among these, displacement of raindrops due to wind drift – which is especially a problem with high-spatial resolution weather radar – is largely ignored in the published literature. This is mainly due to the lack of high-resolution three-dimensional wind fields and feasible treatment of the raindrop size distribution (DSD). In this study, a new systematic approach is proposed to explore the radar–gauge relationship under the wind influence. The mass-weighted mean diameter of raindrops is derived for each radar grid from the DSD data. The reanalysis project ERA-40 data of the European Centre for Medium-range Weather Forecasts (ECMWF) are used to drive the numerical weather research and forecasting (WRF) model to generate high-resolution hourly three-dimensional wind fields. Trajectories and displacements of raindrops are then computed using a three-dimensional motion equation from the given radar beam height to the ground surface. Based on the radar rainfall surface interpolated by the bicubic spline method, the correlation of the radar–gauge pairs is used to validate the results. A case study with 20 storm events in the Brue catchment in South West England is chosen to evaluate the proposed scheme. It has been found that when wind drift is taken into account, the correlation coefficient in hourly gauge–radar comparisons can be enhanced by up to 30% and the average correlation coefficient for an event can be improved by 10%. However, there are still some situations in which the scheme fails to work, indicating the complexity and uncertainties in tackling this challenging problem. Further studies are needed to explore why those cases cause problems to the scheme and how it could be improved to cope with them.