Optimized Unrolling of Nested Loops

Loop unrolling is a well known loop transformation that has been used in optimizing compilers for over three decades. In this paper, we address the problems of automatically selecting unroll factors for perfectly nested loops, and generating compact code for the selected unroll factors. Compared to past work, the contributions of our work include (i) a more detailed cost model that includes register locality, instruction-level parallelism and instruction-cache considerations; (ii) a new code generation algorithm that generates more compact code than the unroll-and-jam transformation; and (iii) a new algorithm for efficiently enumerating feasible unroll vectors. Our experimental results confirm the wide applicability of our approach by showing a 2.2× speedup on matrix multiply, and an average 1.08× speedup on seven of the SPEC95fp benchmarks (with a 1.2× speedup for two benchmarks). Larger performance improvements can be expected on processors that have larger numbers of registers and larger degrees of instruction-level parallelism than the processor used for our measurements (PowerPC 604).     

Egomotion Estimation Using Assorted Features

We propose a novel minimal solver for recovering camera motion across two views of a calibrated stereo rig. The algorithm can handle any assorted combination of point and line features across the four images and facilitates a visual odometry pipeline that is enhanced by well-localized and reliably-tracked line features while retaining the well-known advantages of point features. The mathematical framework of our method is based on trifocal tensor geometry and a quaternion representation of rotation matrices. A simple polynomial system is developed from which camera motion parameters may be extracted more robustly in the presence of severe noise, as compared to the conventionally employed direct linear/subspace solutions. This is demonstrated with extensive experiments and comparisons against the 3-point and line-sfm algorithms.     

Evaluating acid and base catalysts in the methylation of milk and rumen fatty acids with special emphasis on conjugated dienes and total trans fatty acids

Milk analysis is receiving increased attention. Milk contains conjugated octadecadienoic acids (18∶2) purported to be anticarcinogenic, low levels of essential fatty acids, and trans fatty acids that increase when essential fatty acids are increased in dairy rations. Milk and rumen fatty acid methyl esters (FAME) were prepared using several acid-(HCl, BF₃, acetyl chloride, H₂SO₄) or base-catalysts (NaOCH₃, tetramethylguanidine, diazomethane), or combinations thereof. All acid-catalyzed procedures resulted in decreased cis/trans (Δ9c, 11t-18∶2) and increased trans/trans (Δ9t, 11t-18∶2) conjugated dienes and the production of allylic methoxy artifacts. The methoxy artifacts were identified by gas-liquid chromatography (GLC)-mass spectroscopy. The base-catalyzed procedures gave no isomerization of conjugated dienes and no methoxy artifacts, but they did not transesterify N-acyl lipids such as sphingomyelin, and NaOCH₃ did not methylate free fatty acids. In addition, reaction with tetramethylguanidine coextracted material with hexane that interfered with the determination of the short-chain FAME by GLC. Acid-catalyzed methylation resulted in the loss of about 12% total conjugated dienes, 42% recovery of the Δ9c,11t-18∶2 isomer, a fourfold increase in Δ9t,11t-18∶2, and the formation of methoxy artifacts, compared with the base-catalyzed reactions. Total milk FAME showed significant infrared (IR) absorption due to conjugated dienes at 985 and 948 cm⁻¹. The IR determination of total trans content of milk FAME was not fully satisfactory because the 966 cm⁻¹ trans band overlapped with the conjugated diene bands. IR accuracy was limited by the fact that the absorptivity of methyl elaidate, used as calibration standard, was different from those of the other minor trans fatty acids (e.g., dienes) found in milk. In addition, acid-catalyzed reactions produced interfering material that absorbed extensively in the trans IR region. No single method or combination of methods could adequately prepare FAME from all lipid classes in milk or rumen lipids, and not affect the conjugated dienes. The best compromise for milk fatty acids was obtained with NaOCH₃ followed by HCl or BF₃, or diazomethane followed by NaOCH₃, being aware that sphingomyelins are ignored. For rumen samples, the best method was diazomethane followed by NaOCH₃.     

MPI + MPI: a new hybrid approach to parallel programming with MPI plus shared memory

Hybrid parallel programming with the message passing interface (MPI) for internode communication in conjunction with a shared-memory programming model to manage intranode parallelism has become a dominant approach to scalable parallel programming. While this model provides a great deal of flexibility and performance potential, it saddles programmers with the complexity of utilizing two parallel programming systems in the same application. We introduce an MPI-integrated shared-memory programming model that is incorporated into MPI through a small extension to the one-sided communication interface. We discuss the integration of this interface with the MPI 3.0 one-sided semantics and describe solutions for providing portable and efficient data sharing, atomic operations, and memory consistency. We describe an implementation of the new interface in the MPICH2 and Open MPI implementations and demonstrate an average performance improvement of 40 % to the communication component of a five-point stencil solver.     

Effects of Driver and Secondary Task Characteristics on Lane Change Test Performance

The main objective of this study was to examine the sensitivity of the Lane Change Test (LCT) as proposed by International Organization of Standardization by evaluating LCT performance between primary and dual‐task conditions in simulated driving conditions. The study involved four different secondary tasks that involved tracking, visual search, memory, and data entry, each under two different difficulty levels. The primary task involved a series of lane changes on a three‐lane straight roadway where the actual lane change trajectory was compared with a normative model of the trajectory. Thus, the lane change performance was measured by the mean deviation of the actual driving trajectory from the normative trajectory. Twenty‐four participants within three age groups (25–34, 35–45, and >55 years) and equally distributed between male and female took part in the study. Thus, the study also investigated the effect of age and gender on driving performance. The results showed that secondary tasks that require visual attention and psychomotor coordination deteriorated driving performance the most, whereas tasks that required memory scanning and utilization of the auditory modality least affected driving performance. The study also found differences in LCT performances with respect to three different age categories and gender. © 2012 Wiley Periodicals, Inc.     

A Framework for Proof Systems

Linear logic can be used as a meta-logic to specify a range of object-level proof systems. In particular, we show that by providing different polarizations within a focused proof system for linear logic, one can account for natural deduction (normal and non-normal), sequent proofs (with and without cut), and tableaux proofs. Armed with just a few, simple variations to the linear logic encodings, more proof systems can be accommodated, including proof system using generalized elimination and generalized introduction rules. In general, most of these proof systems are developed for both classical and intuitionistic logics. By using simple results about linear logic, we can also give simple and modular proofs of the soundness and relative completeness of all the proof systems we consider.     

The role of hyperarousal in the manifestation of posttraumatic psychological distress following injury.

The authors examined the temporal relation among posttraumatic stress disorder symptom clusters, using data derived from a longitudinal study of survivors of orofacial injury (N = 264). They conducted cross-lagged panel analyses, with self-reported symptom data collected at 1, 6, and 12 months postinjury. Results demonstrate that hyperarousal was a potent predictor of subsequent symptoms of reexperiencing and avoidance as well as hyperarousal. By contrast, neither reexperiencing nor avoidance was significantly related to other symptom clusters other than themselves over time. These findings underscore the distinctive nature of hyperarousal in the manifestation of posttraumatic psychological distress over time. Implications for theory, clinical intervention, and future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synergistic effect of organic and inorganic nano fillers on the dielectric and mechanical properties of epoxy composites

Titanium oxide TiO₂/epoxy and TiO₂ with detonation nano-diamond (DND)/epoxy nanocomposites were prepared by using ultrasonication method. TiO₂ and DND particles as reinforcement species and epoxy as matrix were used to produce nanocomposites. The addition of DND particles into TiO₂/epoxy composite improved the dielectric and mechanical properties of nanocomposites in significant amount. The dielectric properties of TiO₂-DND/epoxy nanocomposite demonstrated increase in permittivity and conductivity after addition of the DND particles. The maximum and minimum reflection losses of TiO₂-DND/epoxy nanocomposite for 0.6 and 0.2 wt% DND loading were detected at ?14.5 and ?1.3 dB, respectively. The flexural and tensile strength of TiO₂-DND/epoxy nanocomposites with the addition of 0.4 wt% DNDs were enhanced to 220% and 223%, respectively. Additionally, the energy to break and percent break strain were 3.9 J and 3.86, respectively for 0.4 wt% DND loading in TiO₂-DND/epoxy nanocomposite. Therefore, the present work findings claim that DND particles are well suitable to enrich the dispersion of TiO₂ nanoparticles in epoxy matrix, which develops a strong load transfer interface between the nanoparticles and epoxy matrix and consequently leads to superior properties.     

Study of the Electronic Structure,Magnetic and Elastic Properties and Half-Metallic Stability on Variation of Lattice Constants for CoFeCr<Emphasis Type="Italic">Z</Emphasis> (<Emphasis Type="Italic">Z</Emphasis> = P,As, Sb) Heusler Alloys

Structural, elastic, magnetic and electronic properties of CoFeCrZ (Z = P, As, Sb) Heusler alloys in their YI-type structure have been computed by density functional theory-based WIEN2k code within generalized gradient approximation for exchange correlation functions. Values of formation energy and elastic constants verify the stability of these alloys. True half metallic ferromagnetic behaviour with 100% spin polarization and good band gap in the minority spin are obtained for all the alloys. Magnetic moment of these alloys is 4.00 μ _B , which matches well with the value predicted from Slater-Pauling rule. Half-metallicity is maintained over a wide range of lattice constants making these alloys promising for spintronics device applications.     

Green synthesis of gold nanoparticles: Its effect on cocoon and silk traits of mulberry silkworm (Bombyx mori L.)

In the present century the small particles are unique phenomenon which can be developed by bottom-up and top-down processes. These small particles may be considered as nanoparticles which help to build up a technology called nanotechnology. Nanomaterials are those materials which possess the length scales below 100 nm and quite often they make a comparison with a human hair, which is about 80,000 nm wide. We have introduced this technology, specially the green synthesis of gold (Au) nanoparticles in silkworm (Bombyx mori L.). The gold nanoparticles clearly indicate that they have a tremendous effect on enhancement of silk proteins and thus the enhancement of the cocoon weight in silkworms. Gold nanoparticles were prepared from onion, Allium cepa L. The extracted green gold nanomaterials from A. cepa were confirmed by UV-Vis spectrophotometer, XRD, FTIR, SEM, TEM and AFM. The function of green gold nanomaterials extracted from A. cepa was tested on silkworm physiology. We have used UV for judgment of the nature of particles and spectrum peak wavelength showed an absorption peak at 535 nm and indicated the wavelength of the surface plasmon resonance in gold nanoparticles (Au NPs). In blank solutions no such absorption peak was observed at 535 nm. Moreover, the gold (Au) XRD spectrum is supposed to and does demonstrate (111), (200), (220), and (311) peaks in the assortment of superimpose on the background. The process includes the (002) trace graphite peaks, where the (111) peak appears to be exceptionally sharp and strong which helps to propose that it is gold in nature. The FTIR shows that the examined particles are gold in nature. In SEM where electrons interact with atoms in the sample, producing various signals that can be detected and that hold information about the sample's surface topography and composition. The electron beam in SEM is generally scanned in a raster scan pattern, and therefore the beam's position is combined and detects the signal to produce an image. SEM can attain a resolution better than 1 nanometer size. The transmission electron microscope helps to accelerate the electrons as a source of elucidation. The AFM measurement is made in three dimensions process and thus it may be measured as horizontal to X-Y plane. Therefore, decree (magnification) measured at Z–direction, which is normally higher than X-Y. The said repulsive force is major one in AFM. Thus the tip and sample may considered to be the specific force in AFM which may measured at Z–direction. The effect of green gold nanoparticles on mulberry silkworm (Bombyx mori L) can exaggerated the silkworm physiological function. Larvae at 50, 100, 200, and 300 ppm doses were studied right from 1st stage to 5th instar stage. Gold nano treatment resulted in significant alterations in the percentage of fibroin and sericin proteins in the 5th instar as compared to that of control. At a 300 ppm dose of green nano gold the percentage of fibroin was 78.07, while sericin decreased from 39.46 (control) to 21.92. It was observed that the green gold nanomaterials have the ability to not only alter the fibroin protein but also enhance the cocoon and silk traits. The aim of this study was to investigate the effect of extra foliation of mulberry leaves with G-GNPs extracted from A. cepa on larval duration, mature silk gland weight, pupal weight, cocoon weight, cocoon shell weight, fibroin and sericins contents, etc. Moreover, the enhanced production of fibroin will explore a new venture in bioengineering and also in biomedical field.