A Methodology for Efficient Tile Size Selection for Affine Loop Kernels

International Journal of Parallel Programming - Reducing the number of data accesses in memory hierarchy is of paramount importance on modern computer systems. One of the key optimizations...     

A model for the estimation of the carrier‐to‐noise plus total interference ratio between two adjacent dual polarized satellite links sharing the same frequency band

In modern satellite communications, matters such as frequency congestion, transmission of dual polarized carriers and increase of the number of geostationary satellites in use, necessitate the implementation of interference analysis in neighbouring networks so as to ensure satisfactory quality of service. In this paper, a recently proposed model for the prediction of the degradation of the carrier‐to‐interference ratio due to differential rain attenuation and cross‐polarization, which is applicable only for the noise‐dominant case, has been properly modified to include the general case. The proposed model is based on the lognormal assumption for the point rainfall rate statistics and the convective raincell model. Due to complexity of the proposed analysis, some simple regression‐derived formulas have been generated forming a very useful tool for the system engineer. The elaborations of numerical results examine the influence of various parameters upon the total availability performance and the optimum utilization of the geostationary orbit. Copyright © 2005 John Wiley & Sons, Ltd.     

A multi-criteria optimisation approach for the design of sustainable utility systems

Large amounts of gaseous emissions are generated by combustion processes associated with the utility systems. The emissions include SO_x, CO₂, CO, NO_x, CH₄, and N₂O. Such emissions can result in significant impact on the surrounding environment. As a result of serious concerns about environmental problems in recent years, the design criteria for a modern utility system should include both environmental and economic requirements. This work proposes a multi-objective optimisation (MOO) strategy to identify the sustainable design of utility systems that satisfies both economic and environmental goals. A MOO mixed integer linear programming (MILP) model is developed to combine the minimisation of costs with the minimisation of environmental impact that is assessed in terms of life cycle environmental burdens. Most of the gaseous emissions are addressed in the model. The resulting MOO problem is solved using lexicographic goal programming (LGP) techniques. The new strategy has been applied to a case study for the design of a utility system with specific utility demands.     

Polyphenolic profile and antioxidant activity of five apple cultivars grown under organic and conventional agricultural practices

The polyphenols and total antioxidant activities of five apple cultivars, grown by organic and conventional agricultural methods in neighbouring farms, were determined and compared. Total polyphenols in the whole fruit and in the peel were determined by the Folin-Ciocalteu method, and the total antioxidant activity was determined by three established methods, diphenyl picrylhydrazyl (DPPH), azinobis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and ferric reducing/antioxidant power (FRAP). Polyphenolic content for the whole fruit was in the range of 80–196 and for the peel 165–400 (mg Gallic Acid Equivalent (GAE)/100 g fresh weight) for both types of agricultural practices. Antioxidant activities of fruit extracts were also relatively similar and well correlated to their polyphenolic content. High-performance liquid chromatography (HPLC) analysis of the most important polyphenolics (chlorogenic acid, catechin, epicatechin, procyanidin B1 and B2, cyaniding 3-galactoside, phloridzin, quercetin 3-galactoside and quercetin 3-arabinoside) also showed that concentrations do not differentiate significantly between the organic and conventional apples. Statistical significance of differences in antioxidant activities among the same cultivars was relatively small (flesh + peel or peel only) for both types of apples. These results indicate that organic apples do not present higher antioxidant or nutritional value compared with conventionally grown ones, as far as polyphenolic content and total antioxidant activities are concerned.     

Comparative study of batch and continuous multi-stage fixed-bed tower (MFBT) bioreactor during wine-making using freeze-dried immobilized cells

A freeze-dried immobilized biocatalyst produced by immobilization of Saccharomyces cerevisiae AXAZ-1 yeast cells on gluten pellets and subsequent freeze-drying was used in a multistage fixed-bed tower (MFBT) bioreactor for batch and continuous wine-making. The MFBT bioreactor resulted in higher alcohol productivity compared to fermentations carried out in a packed bed (PB) bioreactor and showed an important operational stability and no decrease in activity, even at low fermentation temperature (5 °C) and after storage for 6 months at 4 °C. The production of amyl alcohols proved to be temperature dependent and was significantly reduced at low temperatures. Re-activation of the freeze-dried immobilized cells after storage for 6 months resulted in further decreased content of amyl alcohols. The SPME GC/MS analysis of volatile compounds revealed no significant differences in the wines produced by MFBT and PB bioreactors, while the preliminary sensory evaluation ascertained the overall improved quality of the produced wines. Potential industrial application of MFBT bioreactor is also assessed and discussed.     

A study of simple usage‐based charging schemes for broadband networks

Operators of multi‐service networks require simple charging schemes with which they can fairly recover costs from their users and effectively allocate network resources. This paper studies an approach for computing such charges from simple measurements (time and volume), and relating these to bounds of the effective bandwidth. To achieve economic efficiency, it is necessary that usage‐based charging schemes capture the relative amount of resources used by connections. Based on this criteria, we evaluate our approach for real traffic consisting of Internet Wide Area Network traces and MPEG‐1 compressed video. Its incentive compatibility is shown with an example involving deterministic multiplexing, and the effect of pricing on a network's equilibrium is investigated for deterministic and statistical multiplexing. Finally, we investigate the incentives for traffic shaping provided by the approach. This revised version was published online in June 2006 with corrections to the Cover Date.     

Application of statistical design of experiment with desirability function for the removal of organophosphorus pesticide from aqueous solution by low-cost material

This paper deals with the multiple response optimization for the removal of organophosphorus pesticide quinalphos [QP: O,O-diethyl O-2-quinoxalinyl phosphorothioate] from the aqueous solution onto low-cost material and tried to overcome the drawbacks of univariate optimization. Used tea leaves were used as low-cost adsorbent and batch equilibration method was followed for this study. A Box–Behnken design was used to develop response model and desirability function was then used for simultaneous optimization of all affecting parameters in order to achieve the highest removal% of quinalphos. The optimum conditions of factors predicted for quinalphos removal% were found to be: pH 8.83, concentration 7 mg L⁻¹ and dose 0.40 g. Under these conditions, maximum removal% of quinalphos was obtained 96.31%. Considering the above optimum conditions, the adsorption isotherms were developed and provided adsorption capacity of 196.07 μg g⁻¹ by using Langmuir equation, indicating that used tea leaves may be applied as a low-cost material for pesticides removal from aqueous matrices.     

Network intrusion detection: Evaluating cluster, discriminant, and logit analysis

This paper evaluates the statistical methodologies of cluster analysis, discriminant analysis, and Logit analysis used in the examination of intrusion detection data. The research is based on a sample of 1200 random observations for 42 variables of the KDD-99 database, that contains ‘normal’ and ‘bad’ connections. The results indicate that Logit analysis is more effective than cluster or discriminant analysis in intrusion detection. Specifically, according to the Kappa statistic that makes full use of all the information contained in a confusion matrix, Logit analysis (K = 0.629) has been ranked first, with second discriminant analysis (K = 0.583), and third cluster analysis (K = 0.460).     

Ordering fullerene materials at nanometer dimensions

The combination of the hydrophobic fullerene core with hydrophilic functional groups of both ionic and nonionic nature produces organized structures with sizes that range from nanometer to micrometer length scales. The driving force toward this spontaneous organization is the amphiphilic character of the fullerene derivatives. To control both shape and size of the supramolecular assemblies and ultimately their function, important parameters that must be tuned are (i) the balance between the hydrophobic and the hydrophilic moieties, (ii) the effect of the environment, typically provided by simple solvents, (iii) the interface on which the aggregation occurs or, more precisely, surface templating effects, and (iv) the solvation process.