Distance measures for reduced ordering-based vector filters

Reduced ordering-based vector filters have proved successful in removing long-tailed noise from colour images while preserving edges and fine image details. These filters commonly utilise variants of the Minkowski distance to order the colour vectors with the aim of distinguishing between noisy and noise-free vectors. In this study, the authors review various alternative distance measures and evaluate their performance on a large and diverse set of images using several effectiveness and efficiency criteria. The results demonstrate that there are in fact strong alternatives to the popular Minkowski metrics.     

The response of human premolars to cyclic loading

Thirty-seven dogs with moderately differentiated, cutaneous mast cell tumors had incomplete surgical excisions as determined by histopathology, but no gross evidence of tumor. All dogs were irradiated to a total dose of between 46.2 and 48.0 Gy using either an orthovoltage source (n = 20) or a linear accelerator (megavoltage) (n = 17). Radiation was delivered to an area bordered by margins of 3 cm or greater around the surgical scar. The mast cell tumors had not recurred in 97% of dogs by one year after radiation therapy and had not recurred in 93% of dogs by three years after radiation. Both orthovoltage and megavoltage radiation provide excellent local control of moderately differentiated mast cell tumors in dogs.     

Modelling of the Linewidth Enhancement Factor with the Use of Radial Basis Function Network

A different method based on the use of radial basis function network for modelling the linewidth enhancement factor of laser diodes is presented. The learning is achieved using a clustering algorithmfor determining the cluster centres and the extended delta-bar-delta algorithm. The linewidth enhancement factor results presented in this article arein very good agreement with the experimental findings reported elsewhere.     

Hydrothermal Synthesis of Xenotime-Type Gadolinium Orthophosphate

Xenotime-type GdPO₄ (tetragonal, I 4₁/ amd ) has been synthesized hydrothermally at 400°C. X-ray powder data have been presented, and the lattice parameters have been calculated as a = 0.6969(2) nm and c = 0.6095(3) nm.     

On Euclidean norm approximations

Euclidean norm calculations arise frequently in scientific and engineering applications. Several approximations for this norm with differing complexity and accuracy have been proposed in the literature. Earlier approaches [1], [2] and [3] were based on minimizing the maximum error. Recently, Seol and Cheun [4] proposed an approximation based on minimizing the average error. In this paper, we first examine these approximations in detail, show that they fit into a single mathematical formulation, and compare their average and maximum errors. We then show that the maximum errors given by Seol and Cheun are significantly optimistic.     

Utilization of Location Information in Cognitive Wireless Networks

Location awareness is an essential characteristic of cognitive radios as well as networks. In this article a location awareness engine architecture is proposed for the realization of location awareness in cognitive radios and networks. The proposed architecture consists of location estimation and/or sensing, seamless positioning and interoperability, statistical learning and tracking, security and privacy, mobility management, and location-based applications. However, the focus of this article is on location-based applications where we demonstrate the utilization of location information in cognitive wireless networks by presenting some representative location-assisted network optimization applications such as location-assisted spectrum management, network planning and expansion, and handover. Our study unveils that location information can be used in cognitive wireless networks to optimize network performance. Possible solutions to the implementation issues are proposed, and the remaining open issues are also addressed.     

Interblock interference (IBI) and time of reference (TOR)computation in OFDM systems

Orthogonal frequency-division multiplexing (OFDM) is a popular line code scheme that has found application in wideband modem technologies such has asynchronous digital subscriber loop, high bit rate digital subscriber loop, in addition to digital audio broadcast, digital television terrestrial broadcast, and mobile data communication. To prevent interblock interference (IBI), OFDM inserts a guard time sequence, called the cyclic prefix (CP), between each transmitted block. In practice, CP is rarely long enough for the complete elimination of IBI. Understanding the nature of IBI is crucial in subduing its adverse effects. This study characterizes the power spectral density of the IBI in terms of the channel impulse response and the cyclic prefix length. One of the key findings is that the samples of the impulse response tails do not contribute to IBI power uniformly, but rather their contributions grow linearly as the samples move closer to the edges of impulse response. Based on this observation, the study proposes a time of reference computation technique that minimizes the total IBI power as seen by the receiver     

Colour quantisation using the adaptive distributing units algorithm

Colour quantisation (CQ) is an important operation with many applications in graphics and image processing. Most CQ methods are essentially based on data clustering algorithms one of which is the popular k-means algorithm. Unfortunately, like many batch clustering algorithms, k-means is highly sensitive to the selection of the initial cluster centres. In this paper, we adapt Uchiyama and Arbib’s competitive learning algorithm to the CQ problem. In contrast to the batch k-means algorithm, this online clustering algorithm does not require cluster centre initialisation. Experiments on a diverse set of publicly available images demonstrate that the presented method outperforms some of the most popular quantisers in the literature.     

Carbon nanofiber growth on carbon paper for proton exchange membrane fuel cells

Homogeneous deposition precipitation (HDP) of nickel has been investigated for the growth of carbon nanofibers (CNFs) on carbon paper for use in proton exchange membrane fuel cells as a gas diffusion layer. Selective CNF growth on only one side of carbon paper is required to transfer the generated protons on platinum catalyst fast enough to avoid any proton mass transfer losses. For this purpose, a mask deposition holder was designed to deposit the nickel hydroxide which is reduced to nickel with hydrogen before catalyzing the CNF growth. The deposition time effect on the catalyst loading and the effect of the catalyst loading variation on the yield of CNF growth on carbon paper were investigated. Both effects had linear dependence in the region of interest. The HDP of nickel on the carbon paper ensured strong attachment of nickel crystals on the carbon paper fibers keeping the porosity at a promising level with an acceptable BET area of CNFs. The HDP method provides fine-tuning in the CNF layer thickness only on one side of the carbon paper with good reproducibility in the deposition of nickel.     

The effects of sources of supplemental fat on performance,egg quality,and fatty acid composition of egg yolk in laying hens

BACKGROUND: The objective of this study was to determine the effects of sources of supplemental fat on laying performance, egg quality, and fatty acid composition of egg yolk. RESULTS: Two hundreds Isa Brown layers were assigned randomly to be fed ad libitum a standard commercial layer feed (BD), basal diet plus 2% tallow (T), basal diet plus a mixture of 1% tallow and 1% flaxseed oil (MTFO), basal diet plus 2% sunflower oil (SO), or basal diet plus 2% flaxseed oil (FO), which were offered for 8 weeks. Each diet was given to five groups, each containing 10 hens. The feed efficiency and egg production were 2.78 and 53.51% for BD; 2.30 and 63.47% for T; 2.45 and 60.14% for MTFO; 2.29 and 64.30% for SO, and 2.62 and 61.18% for FO groups, respectively. Dietary fat supplementation affected the laying performance but had no significant effects on egg quality parameters. The fatty acid composition of egg yolk lipids were significantly affected by dietary fatty acid composition. The supplemental tallow increased palmitic fatty acid. The proportions of linoleic and arachidonic fatty acids in egg yolks for layers fed the SO diet were higher than in the BD group and those on diets containing other fats. Concentrations of oleic and omega‐3 fatty acids were the highest in layers fed the FO diet during the laying period. CONCLUSION: The results indicated that dietary animal and plant fats changed the fatty acid composition of egg yolk. Copyright © 2008 Society of Chemical Industry