Modified Shuffled Based Architecture for High-Throughput Decoding of LDPC Codes

Low Density Parity-Check (LDPC) codes achieve the best performance when they are decoded with the sum-product (SP) algorithm. This is a two-phase iterative algorithm where two types of messages are interchanged and updated in each iteration. The group-shuffled or layered decoding schemes applied to the SP algorithm speed up its convergence by modifying its schedule, so they yield a reduction in the number of iterations required to achieve a given performance. However, the two-phase processing is still maintained. In this paper a modification of the group-shuffled scheme suitable for high-rate LDPC codes is proposed. The modification allows the overlapping of the two-phase computation, achieving a convergence speed up close to that of the group-shuffled scheme with higher throughput. Besides, high throughput architectures are presented for the modified algorithm. As an example, the proposed architecture has been implemented for the 2048-bit LDPC code of the IEEE 802.3an standard and it was synthesized in a 90 nm CMOS process achieving a throughput of 22.40 Gbps at 14 iterations with a clock frequency of 306 MHz and a total area of 10.5 mm². Furthermore, the decoder performs within 0.5 dB of the floating-point 100 iterations sum-product algorithm at a PER of 10⁻⁵.     

Regression and correlation analyses of a linear relation between random intervals

In this paper we develop regression and corrclation analyses of a certain general linear relation between two random elements whose values are non-empty compact intervals. To this purpose, we firstly extend the least-squares method to deal with the involved random elements on the basis of a generalized metric defined on the space of the considered intervals. As a complementary study, a coefficient quantifying the strength of the linear relation between the two random elements is also presented, and a discussion of the extreme values for this measure is presented. A real-life example illustrates these studies. Research partially supported by DGESIC/MEC Grants No. DGE-99-PB98-1534 and No. DGE-98-PB97-1282.     

Effect on wear resistance of nanoparticles addition to a powder polyester coating through ball milling

The wear properties of a textured polyester powder coating with pyrogenic silica nanoparticles addition were evaluated. Raw powders of a commercial, textured polyester organic coating were mixed with low amounts of SiO₂ nanoparticles (0.5–3 wt%) using ball milling, a simple and economical method. Nanoparticles were mixed into the powder of thermoset organic coating for 10 min in a two-body planetary ball mill. Particle size distribution of the powder was measured to evaluate the milling effect. The coatings were applied and cured in an industrial installation on aluminum substrates. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) images of the coatings were taken to analyze the homogeneity of the organic coating. Roughness, gloss and color were measured in order to evaluate their appearance. The effect of nanoparticles on abrasive and erosion wear performances was measured. Pin-on-disk wear tests were carried out. Erosion measurements were performed with free fall of sand on the samples, a test based on ASTM D968 standard. The results showed that the milling process provides a good distribution of nanoparticles as no agglomerates were found. The addition of 0.5 wt% silica nanoparticles allows for improvement of the wear resistance of the coatings.     

Two-Dimensional Compact Third-Order Polynomial Reconstructions. Solving Nonconservative Hyperbolic Systems Using GPUs

We present a new kind of high-order reconstruction operator of polynomial type, which is used in combination with the scheme presented in Castro et al. (J. Sci. Comput. 39:67?C114, 2009) for solving nonconservative hyperbolic systems. The implementation of the scheme is carried out on Graphics Processing Units (GPUs), thus achieving a substantial improvement of the speedup with respect to normal CPUs. As an application, the two-dimensional shallow water equations with geometrical source term due to the bottom slope is considered.     

Antioxidative activity and general fruit characteristics in different traditional orange [<Emphasis Type="Italic">Citrus sinensis</Emphasis> (L.) Osbeck] varieties

Genotypic variation in some attributes related to fruit quality and total antioxidative activity (TAA) were evaluated in 16 traditional orange varieties and in the Naveline variety, nowadays the most commonly cultivated in Spain. Significant differences were found in fruit weight, soluble solid content, titratable acidity and scores for sensory analysis among orange varieties. TAA in orange juice ranged between ca. 40 and 140 mg ascorbic acid equivalent/100 g of juice depending on variety, and contributed to the TAA of the fruits edible tissues by more than 99.5%. TAA in orange juice correlated to ascorbic acid concentration, and was responsible for 50–82% of the TAA evaluated. According to the TAAs of the orange fruits and the sensory analysis results, Guasi, Newhall and Capuchina varieties would be the most appropriate for consumption, owing to their desirable organoleptic properties, and in order to increase the dietary intake of antioxidative compounds and their health-promoting effects.     

Soft computing techniques applied to finance

Soft computing is progressively gaining presence in the financial world. The number of real and potential applications is very large and, accordingly, so is the presence of applied research papers in the literature. The aim of this paper is both to present relevant application areas, and to serve as an introduction to the subject. This paper provides arguments that justify the growing interest in these techniques among the financial community and introduces domains of application such as stock and currency market prediction, trading, portfolio management, credit scoring or financial distress prediction areas.     

Increase in plasma thyrotropin levels in hypothyroid patients during treatment due to a defect in the commercial preparation

Around mid-1995, the Molecular Endocrinology Laboratory of the Regional Hospital (Malaga, Spain) began detecting an increase in TSH levels in the serum of patients under study to control the treatment of hypothyroidism with levothyroxine. Over a period of 5 months, of a total of 467 hypothyroid patients treated with Levothyroid, 53% had TSH levels higher than 6 microU/mL. The reliability of the biochemical results was verified by duplicating 56 randomly chosen samples from all those with high TSH levels and by an external control performed in four different laboratories. The amount of levothyroxine in the tablets was analyzed by RIA, high performance liquid chromatography, and their iodine contents. The lowest levels of levothyroxine found in the 50 micrograms Levothyroid tablets were those determined by RIA, with a mean value of 32.3 micrograms, resulting in a 35.3% loss of activity. The mean value of levothyroxine found in these same tablets by high performance liquid chromatography was 39.3 micrograms, amounting to a 21.3% loss in activity. The iodine showed no significant loss in these tablets, with a mean experimental value of 48 micrograms. The commercial laboratory withdrew lot J from the market, the one in which these deficiencies were found.