Time and Energy Performance of Parallel Systems with Hierarchical Memory

In this paper we analyze the impact of memory hierarchies on time-energy trade-off in parallel computations. Contemporary computing systems have deep memory hierarchies with significantly different speeds and power consumptions. This results in nonlinear phenomena in the processing time and energy usage emerging when the size of the computation is growing. In this paper the nonlinear dependence of the time and energy on the size of the solved problem is formalized and verified using measurements in practical computer systems. Then it is applied to formulate a problem of minimum time and minimum energy scheduling parallel processing of divisible loads. Divisible load theory is a scheduling and performance model of data-parallel applications. Mathematical programming is exploited to solve the scheduling problem. A trade-off between energy and schedule length is analyzed and again nonlinear relationships between these two criteria are observed. Further performance analysis reveals that energy consumption and schedule length are ruled by a complex interplay between the costs and speeds of on-core and out-of-core computations, communication delays, and activating new machines.     

Scheduling multiple divisible loads in homogeneous star systems

In this paper we analyze scheduling multiple divisible loads on a star-connected system of identical processors. It is shown that this problem is computationally hard. Some special cases appear to be particularly difficult, so it is not even known if they belong to the class NP. Exponential algorithms and special cases solvable in polynomial time are presented. M. Drozdowski’s research partially supported by Polish Ministry of Science and Higher Education.     

Scheduling divisible loads with time and cost constraints

In distributed computing, divisible load theory provides an important system model for allocation of data-intensive computations to processing units working in parallel. The main task is to define how a computation job should be split into parts, to which processors those parts should be allocated and in which sequence. The model is characterized by multiple parameters describing processor availability in time, transfer times of job parts to processors, their computation times and processor usage costs. The main criteria are usually the schedule length and cost minimization. In this paper, we provide the generalized formulation of the problem, combining key features of divisible load models studied in the literature, and prove its NP-hardness even for unrestricted processor availability windows. We formulate a linear program for the version of the problem with a fixed number of processors. For the case with an arbitrary number of processors, we close the gaps in the study of special cases, developing efficient algorithms for single criterion and bicriteria versions of the problem, when transfer times are negligible.

     

Effect of the unsaturated acyl position in triglycerides on the Hydrogenation rate

Linseed and cod liver oil triglycerides as well as the randomly rearranged triglycerides of soybean and rapeseed oils were subjected to partial hydrogenation in the presence of nickel or platinum catalyst. The hydrogenated triglycerides were subjected to enzymatic hydrolysis with pancreatic lipase in order to determine the changes of their structure. It follows from the data obtained that the position of an unsaturated acyl in a triglyceride affects its hydrogenation rate.     

The age-related decline in intestinal lipid uptake is associated with a reduced abundance of fatty acid-binding protein

Aging is associated with changes in the absorptive capacity of the small intestine. We tested the hypotheses that (i) aging is associated with a decline in lipid absorption, and that (ii) this decreased lipid absorption is due to a decline in the abundance of mRNA and/or the enterocyte cytosolic intestinal FA-binding protein (I-FABP), the liver FA-binding protein (L-FABP), and the ileal lipid-binding protein (ILBP). In vitro uptake studies were performed on Fischer 344 rats at ages 1, 9, and 24 mon. Northern blotting (L-FABP, ILBP) and immunohistochemistry (I-FABP, ILBP) were performed. Aging was associated with decreased animal weights, but the surface area of the intestine was not significantly altered with age. The rates of ileal uptake of 16∶0, 18∶0, 18∶1, and 18∶2 were reduced by greater than 50% with aging when expressed on the basis of mucosal weight. This decline was not associated with reduced expression of mRNA for L-FABP or ILBP but was associated with a 50% decrease in the abundance of I-FABP and a 40% decrease in the abundance of ILBP. Thus, the decrease with aging in the ileal uptake of some FA when rates were expressed on the basis of mucosal weight was associated with a reduced abundance of I-FABP and ILBP.     

VUV spectroscopy and low temperature thermoluminescence of LSO:Ce and YSO:Ce

Radioluminescence and UV-excited photoluminescence spectra, photoluminescence time profiles, thermoluminescence glow curves and gamma-excited energy spectra (determining scintillation light yields) of several Lu₂SiO₅:Ce and Y₂SiO₅:Ce samples were recorded. The results are analyzed with attention focused on possible correlations between trap distributions, VUV responses, and light yields. The aspect of two distinct sites occupied by Ce³⁺ ions is also discussed.     

Isopropyl alcohol extraction of oil and lipids in the production of fish protein concentrate from herring

The extraction of lipid from fatty fish (herring) by the Halifax process for producing fish protein concentrate, using isopropyl alcohol (IPA), is virtually complete. The largest portion of the lipid is found in the first extract and high quality triglyceride oil is readily recovered by cooling this extract; under certain circum-stances it can also be recovered from the second extract. The phospholipids are extracted without obvious degradation and together with free fatty acids are found mostly in the IPA-rich phase from the first extraction. Residual lipid in fish protein concentrate resembles the starting lipid of the fish. Detailed fatty acid compositions are given for various materials.     

Selective hydrogenation of rapeseed oils with copper-chromite catalyst: Influence of erucic acid

Rapeseed oils with different erucic acid contents have been hydro-genated in a “dead-end” type of laboratory reactor with Adkins-type copper-chromite catalyst. It was observed that, as is true with oleic acid, erucic acid is not hydrogenated by this catalyst, but it differs in that positional or geometrical isomerization does not occur. The presence of erucic acid does not change the mechanism of hydrogenation of rapeseed oils in a range of concentrations of this acid. On the other hand, it markedly influences the rate of reaction.     

Particle clustering in photocurable nanocomposites: Dependence of curing kinetics and viscoelastic properties

The aim of this article is to investigate the effect of nanoparticle clustering on the mobility of nanoparticles in nanocomposites, using spectroscopic methods (Brillouin and Raman). Special attention is paid to the effect of particle clustering on photocuring kinetics. The model system was poly(2‐hydroxyethyl acrylate) filled with fumed nanosilica in concentration range encompassing the percolation threshold. Results obtained from Brillouin spectroscopy show substantial changes in the sound velocity and the attenuation coefficient with increasing filler content. The damping of acoustic waves reaches the maximum at the percolation threshold (～15 wt %), which is related to changes in the mechanism of acoustic wave propagation. The formation of the cocontinuous silica phase strongly affects the curing kinetics of the monomer/silica system: the polymerization rate is the highest at a silica content corresponding to the percolation threshold. These results correlate well with the results of AFM surface roughness analysis. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39895.     

Using spreadsheets in student exercises for signal and linearsystem analysis

Several student exercises in signal and linear system analysis that use the power of PC-based spreadsheet programs to aid students' understanding and cognitive development are presented. The first exercise examines the Fourier series and allows students to see graphically how the harmonics of the series add and subtract to form a new periodic waveform. In the second assignment, students work through problems designed to acquaint them with implementing singularity functions and integration methods on the path to accomplishing the convolution of two signals. The final exercise teaches students how to form iterative solutions to state space problems. The exercises allow students to focus on gaining a conceptual understanding of signal and linear system analysis while deemphasizing the rigors of developing a user interface, a common problem when using structured programming languages