Reducing cell loss in banyan based ATM switching fabrics

In this paper, we propose a new technique for reducing cell loss in multi‐banyan‐based ATM switching fabrics. We propose a switch architecture that uses incremental path reservation based on previously established connections. Path reservation is carried out sequentially within each banyan but multiple banyan planes can be concurrently reserved. We use a conflict resolution approach according to which banyans make concurrent reservation offers of conflict‐free paths to head of the line cells waiting in input buffers. A reservation offer from a given banyan is allocated to the cell whose source‐to‐destination path uses the largest number of partially allocated switching elements which are shared with previously reserved paths. Paths are incrementally clustered within each banyan. This approach leaves the largest number of free switching elements for subsequent reservations which has the effect of reducing the potential of future conflicts and improves throughput. We present a pipelined switch architecture based on the above concept of path‐clustering which we call path‐clustering banyan switching fabric (PCBSF). An efficient hardware that implements PCBSF is presented together with its theoretical basis. The performance and robustness of PCBSF are evaluated under simulated uniform traffic and ATM traffic. We also compare the cell loss rate of PCBSF to that of other pipelined banyan switches by varying the switch size, input buffer size, and traffic pattern. Copyright © 2001 John Wiley & Sons, Ltd.     

Surface Chemistry of Vitamin: Pyridoxal 5′‐Phosphate (Vitamin B6) as a Multifunctional Compound for Surface Functionalization

Vitamins are non‐toxic compounds that perform a variety of biological functions and also available in a large quantity. Other than the usage as food supplements, few attempts have been made to use them as functional materials. In this study, we report that vitamin B6, pyridoxal 5′‐phosphate (PLP), is a multi‐functional molecule for oxide surface chemistry. PLP‐immobilized surfaces exhibit superhydrophilicity and even hemophilicity, enhancing proliferation, migration, and differentiation of mammalian cells. Unlike existing molecules used so far in surface modification, PLP has an intrinsic chemical reactivity toward biomacromolecules due to the presence of the aldehyde group. In fact, RGD peptide is covalently tethered onto PLP surfaces directly in one step without any chemical activation. Furthermore, PLP‐functionalized implant device showed rapid bone healing. As vitamin B6 is a FDA approved molecule for human usage, the surface chemistry of vitamin B6 potentially allows a fast route for surface functionalized medical devices into clinic.     

LTE uplink MIMO receiver with low complexity interference cancellation

In LTE/LTE-A uplink receiver, frequency domain equalizers (FDE) are adopted to achieve good performance. However, in multi-tap channels, the residual inter-symbol and inter-antenna interference still exist after FDE and degrade the performance. Conventional interference cancellation schemes can minimize this interference by using frequency domain interference cancellation. However, those schemes have high complexity and large feedback latency, especially when adopting a large number of iterations. These result in low throughput and require a large amount of resource in software defined radio implementation. In this paper, we propose a novel low complexity interference cancellation scheme to minimize the residual interference in LTE/LTE-A uplink. Our proposed scheme can bring about 2 dB gains in different channels, but only adds up to 7.2 % complexity to the receiver. The scheme is further implemented on Xilinx FPGA. Compared to other conventional interference cancellation schemes, our scheme has less complexity, less data to store, and shorter feedback latency.     

Transformation champ proche — champ lointain bidimensionnelle et monodimensionnelle appliquée à des mesures de SER

In high frequency thercs measurement of large target must be done at important distances, so the distance of measurement (Fraunhofer’s distance) R is given by R ≥ 2d² /λ where d is the tranversal length of the target and λ the radiation wavelength. In this paper we present a method for target that are large relative to the curvature of the spherical wavefront and the curvature of the cylindrical wavefront. A two-dimensional analytical algorithm transforms the spherical wave (near-field) measurement into the desired plane wave (far-field) and a one-dimensionnal analytical algorithm transforms the cylindrical wave (near-field) measurement into the desired plane wave (far-field). We present some results on simulations and measurements. A comparison of one-dimensional and two-dimensional methods demonstrates the efficiency of the two dimensional methods.     

Value‐centric framework and pareto optimality for design and acquisition of communication satellites

Investments in space systems are substantial, indivisible, and irreversible, characteristics of high‐risk investments. Traditional approaches to system design, acquisition, and risk mitigation are derived from a cost‐centric mindset, and as such they incorporate little information about the value of the spacecraft to its stakeholders. These traditional approaches are appropriate in stable environments. However, the current technical and economic conditions are distinctly uncertain and rapidly changing. Consequently, these traditional approaches have to be revisited and adapted to the current context. We propose that in uncertain environments, decision‐making with respect to design and acquisition choices should be value‐based. We develop a value‐centric framework, analytical tools, and an illustrative numerical example for communication satellites. Our two proposed metrics for decision‐making are the system's expected value and value uncertainty. Expected value is calculated as the expected NPV of the satellite. The cash inflow is calculated as a function of the satellite loading, its transponder pricing, and market demand. The cash outflows are the various costs for owning and operating the satellite. Value uncertainty emerges due to uncertainties in the various cash flow streams, in particular because of market conditions. We propagate market uncertainty through Monte Carlo simulation, and translate it into value uncertainty for the satellite. The end result is a portfolio of Pareto‐optimal satellite design alternatives. By using value and value uncertainty as decision metrics in the down‐selection process, decision‐makers draw on more information about the system in its environment, and in making value‐based design and acquisition choices, they ultimately make more informed and better choices. Copyright © 2009 John Wiley & Sons, Ltd.     

The Impact of Political Talk Radio Exposure on Attributions About the Outcome of the 1996 U.S. Presidential Election

This study investigates the media's potential to affect audiences' interpretations of news events. It compares perceptions of the causes of the 1996 presidential election outcome across four media consumption groups: listeners to the program of Rush Limbaugh, listeners to other political talk radio, consumers of mainstream news media, and nonconsumers of news media. Limbaugh listeners were more likely to discount substantive election explanations than were consumers of other types of political talk radio, consumers of mainstream news media, and nonconsumers of news media. These differences in interpretation parallel differences between the content of his program and that of other media.     

Communication capabilities of product networks

Instead of providing separate solutions for each individual network, a unified theory is desirable to cover the study of a class of networks. Cartesian product graphs provide a common framework to investigate the performance of several individual networks. This paper addresses communication capabilities of product networks. Communication cost is generally characterized by the diameter, the average distance, the total number of paths, the traffic intensity, the saturation level, the queue length in each node, the communication delay and the network throughput. The diameter and average distance of product networks have been studied. However, no work has addressed the remaining measures for product networks. This paper presents a unified theory to evaluate the traffic intensity and the saturation level of product networks. We have theoretically computed the traffic intensity and the saturation level. Intensive simulations have been conducted to validate the analytical results and to compute the other measures for different workloads, different networks, and different network sizes. Examples of product networks that have been investigated are multidimensional meshes, multidimensional toruses, and r‐ary n‐cube networks. We have also shown that the structure (geometry) of a network is a primary factor for network high performance. For meshes and toruses, square networks present an optimal structure. While in case of an r‐ary n‐cubes, networks with higher radix outperform those with smaller radix. In particular, cross‐cubes (4‐ary n‐cube) are shown to perform better than binary cubes. This revised version was published online in June 2006 with corrections to the Cover Date.     

Substitution of wheat starch with non-wheat starches and cross-linked waxy barley starch affects sensory properties and staling of Arabic bread

Substitution of starch from barley, corn, oat, potato, rice or sorghum for prime wheat starch in the formulation of Arabic bread resulted in breads with significantly (P < 0.05) different textural attributes from regular wheat bread except for barley starch. Substitution of waxy barley starch (957 g kg⁻¹ amylopectin) for wheat starch (279 g kg⁻¹ amylopectin) resulted in bread that was not significantly different from regular wheat bread when assessed in the fresh state. However, upon aging, the waxy barley starch-containing bread staled at a significantly (P < 0.05) faster rate than regular wheat bread. Breads made with waxy barley starch cross-linked with 50, 200 or 500 ppm phosphorus oxychloride showed higher enthalpy of melting (ΔH) upon aging and staled faster than the bread formulated with waxy barley starch. These findings suggest that amylopectin retrogradation is one of the determinants of Arabic bread staling and that cross-linking promotes recrystallisation of amylopectin, possibly by keeping the polymer chains in close proximity. The rate of staling in breads formulated with cross-linked waxy barley starch decreased with increasing levels of cross-linking, possibly owing to restrictions in the degree of starch swelling. © 1999 Society of Chemical Industry     

Location Estimation via Support Vector Regression

Location estimation using the global system for mobile communication (GSM) is an emerging application that infers the location of the mobile receiver from multiple signals measurements. While geometrical and signal propagation models have been deployed to tackle this estimation problem, the terrain factors and power fluctuations have confined the accuracy of such estimation. Using support vector regression, we investigate the missing value location estimation problem by providing theoretical and empirical analysis on existing and novel kernels. A novel synthetic experiment is designed to compare the performances of different location estimation approaches. The proposed support vector regression approach shows promising performances, especially in terrains with local variations in environmental factors