Genetic algorithms for task scheduling problem

The scheduling and mapping of the precedence-constrained task graph to processors is considered to be the most crucial NP-complete problem in parallel and distributed computing systems. Several genetic algorithms have been developed to solve this problem. A common feature in most of them has been the use of chromosomal representation for a schedule. However, these algorithms are monolithic, as they attempt to scan the entire solution space without considering how to reduce the complexity of the optimization process. In this paper, two genetic algorithms have been developed and implemented. Our developed algorithms are genetic algorithms with some heuristic principles that have been added to improve the performance. According to the first developed genetic algorithm, two fitness functions have been applied one after the other. The first fitness function is concerned with minimizing the total execution time (schedule length), and the second one is concerned with the load balance satisfaction. The second developed genetic algorithm is based on a task duplication technique to overcome the communication overhead. Our proposed algorithms have been implemented and evaluated using benchmarks. According to the evolved results, it has been found that our algorithms always outperform the traditional algorithms.     

Intelligent QoS management for multimedia services support in wireless mobile ad hoc networks

In this paper, we propose a new intelligent cross-layer QoS support for wireless mobile ad hoc networks. The solution, named FuzzyQoS, exploits fuzzy logic for improving traffic regulation and the control of congestion to support both real-time multimedia (audio/video) services and non-real-time traffic services. FuzzyQoS includes three contributions: (1) a fuzzy logic approach for best-effort traffic regulation (FuzzyQoS-1), (2) a new fuzzy Petri nets technique (FuzzyQoS-2) for modeling and analyzing the QoS decision making for traffic regulation control, and (3) a fuzzy logic approach for threshold buffer management (FuzzyQoS-3). In FuzzyQoS-1, the feedback delay information received from the network is used to perform a fuzzy regulation for best-effort traffic. Using fuzzy logic, FuzzyQoS-3 uses fuzzy thresholds to adapt to the dynamic conditions. The evaluation of FuzzyQoS performances was studied under different mobility, channel, and traffic conditions. The results of simulations confirm that a cross layer design using fuzzy logic at different levels can achieve low and stable end-to-end delay, and high throughput under different network conditions. These results will benefit delay- and jitter-sensitive real-time services.     

PPT-Multicore: performance prediction of OpenMP applications using reuse profiles and analytical modeling

The Journal of Supercomputing - We present PPT-Multicore, an analytical model embedded in the Performance Prediction Toolkit (PPT) to predict parallel applications’ performance running on a...     

Occurrence of Vibrio spp. in blue mussels (Mytilus edulis) from the German Wadden Sea

The present study aimed at determining the contamination of blue mussels grown in Germany with relevant bacterial organisms. Seasonal variations were examined. For that purpose, mussel samples were taken regularly between June 2004 and May 2005 in seven shellfish-growing areas of the German Wadden Sea. A total of 90 samples were analysed. The analysis included the compulsory microbiological parameters Escherichia coli and Salmonella spp., as well as the determination of the contamination with Vibrio spp. Although the analysed mussels complied with the legislation in force, potential human pathogens were detected in a wide range of samples. Vibrio spp. was detected in 74.4% of the samples analysed in this study. Among Vibrio isolates, Vibrio alginolyticus was the species most frequently detected (51.2%), followed by Vibrio parahaemolyticus (39.5%). Vibrio vulnificus was detected in 3.5% of the samples. V. parahaemolyticus and V. vulnificus were not found in samples collected at low water temperatures. The results indicate that blue mussels from shellfish-growing areas in the German Wadden Sea regularly contain pathogens relevant to public health. They also show that E. coli is not a reliable indicator for the contamination with Vibrio spp. To improve consumer protection, it therefore seems necessary to extend the analysis of mussels for direct human consumption by additional parameters.     

Seasonal occurrence and toxicity of Microcystis spp. and Oscillatoria tenuis in the Lebna Dam, Tunisia

Physicochemical and biological water quality, including the total microcystin concentrations, was investigated for the first time from January to December 2005 in the Lebna Dam, Tunisia. Microcystin levels and characterization of the different microcystin variants present were measured by protein phosphatase (PP2A) inhibition assays and by LC/MS/MS, respectively. Nutrient values were high, with total inorganic nitrogen and phosphorus concentrations ranging from 0.05 to 8.4 mg L(-1) and from 0.03 to 1.37 mg L(-1), respectively. However, the chlorophyll-a concentrations were very low with a peak (5.32 microg L(-1)) on 20 September 2005 at 9 m depth water samples. Microscopic examination of the phytoplankton samples showed the dominance in the autumn of three morphospecies of the genus Microcystis and the species Oscillatoria tenuis. The total (particulate and dissolved) microcystin concentrations at the surface and at 9 m depth water samples ranged between 0.008 and 1.73, and 0.005 and 5.57 microg microcystin (MC)-LR equivalent L(-1), respectively, with a peak on 20 September. The presence of the microcystin synthetase genes (mcyA, -B, and -C) in the lysates of the three morphospecies of the genus Microcystis and the species O. tenuis indicated that these species were responsible for the microcystin production in this system. The analysis of the field cyanobacterial sample extract containing these species by LC/MS/MS revealed the presence of two microcystin variants: microcystin-LR (MC-LR) and microcystin-YR (MC-YR).     

Phenolic Composition,Essential Oil,and Antioxidant Activity in the Aerial Part of Artemisia Herba-Alba from Several Provenances: A Comparative Study

This study characterized the phenolic, aroma compositions, and antioxidant capacities of four Artemisia herba alba accessions collected from north and center regions in Tunisia in order to select valuable origin with optimal bioactive compounds production. The total polyphenol and flavonoid contents varied between accessions with maxima contents observed in center regions. Kaempherol, apigenin, naringenin, p-coumaric, trans-cinnamic, and caffeic acids were the most abundant compounds with percentage varying depending on the considered accession. Significant changes on essential oil yields (0.4–1.2%) were found between accessions and three different oil chemotypes were distinguished: camphor, fenchol/α-thujone, and α-thujone/camphor. Cluster analysis of volatile and phenolic compositions grouped the accessions on different groups. Antioxidant activities of extracts were found to be higher than essential oils for the four provenances. The results suggested that the center regions have high potential for selecting varieties rich on essential oil, antioxidant phenolic acids, and flavonoids.     

Pea and Broad Bean Pods as a Natural Source of Dietary Fiber: The Impact on Texture and Sensory Properties of Cake

Attention has focused on bakery products such as cake which is one of the most common bakery products consumed by people in the world. Legume by‐products, pea pods (PPs) (Pisum sativum L.) and broad bean pods (BBPs) (Vicia faba L.) mediterranean (Tunisian), has been studied for its high dietary fiber content (PP: 43.87 g/100 g; BBP: 53.01 g/100 g). Protein content was also a considerable component for both by‐products. We investigated the effect of substituted of 5%, 10%, 15%, 20%, 25%, and 30% of PP and BBP flours on the sensory and technological properties in cake. Cakes hardness increased whereas L^* and a^* color values decreased. The overall acceptability rate showed that a maximum of 15% of PP and BBP flours can be added to prepare acceptable quality cakes.     

Formation, Characterization and Electrical Conductivity of Polycarbosilazane-Cu(II), -Ni(II) and -Cr(III) Chloride Metallopolymers

A series of transition metal-polycarbosilazane complexes have been prepared by the reaction of poly(N,N-bis(dimethylsilyl)ethylenediamine), [–Si(CH₃)₂NHCH₂CH₂NH–] _n , with Cu(II), Ni(II), and Cr(III) chloride. The resulting complexes were characterized by infrared (FT-IR) and UV-visible spectroscopy, magnetic susceptibility measurements, thermogravimetric analysis (TGA), and powder X-ray diffraction (XRD). The average chain-chain spacing in these materials were estimated from XRD data and found to be 6.88, 7.91, 7.09, and 6.33 Å in metal-free, Cu(II)-, Ni(II)-, and Cr(III)-containing polycarbosilazanes, respectively. DC electrical conductivity measurements showed that all these metal-polycarbosilazane complexes exhibit semiconductor behavior while the metal-free matrix is an insulator.     

Bewertung von Setzungsmessungen flachgegründeter Gebäude in weichen Böden

Evaluation of settlement measurements of buildings with shallow foundation on soft soils. Available settlement measurements of 10 buildings with shallow foundations on lacustrine clay in Southern Germany represent the basis of a statistical evaluation of the primary‐ as well as the creep‐settlement. Generally, the measurements show that the predicted settlements using the standard one‐dimensional consolidation tests are significantly larger than the actually occurred settlements. According to the evaluation a correction factor to the calculation of settlement in soft soils was derived. By means of back‐analysis of the measured settlements the coefficients of the consolidation and the secondary compression are determined so that the time‐settlement behavior could be also investigated.     

A self learned invasive weed-mixed biogeography based optimization algorithm for RFID network planning

The optimal placement of the RFID readers inaugurates an ongoing research field, namely the RFID network planning (RNP). The main issue in the RNP is to know how many readers have to be used and what is their best distribution that guarantees fulfillment of multiple objectives. The common RNP objectives are the optimal coverage, readers’ interference avoidance, redundant reader elimination, load balance among deployed readers and minimum power losses, which are considered as conflicting objectives that leads the RNP to be an NP-hard problem need to be solved. The contributions in this paper are: firstly, utilizing both the Biogeography based optimization (BBO) and the Hybrid Invasive Weed-Biogeography based optimization (HIW-BBO) as new algorithms have not used before for solving the RNP. Secondly, we proposed a Self Learning (SL) strategy with a mixed BBO Migration (MBBOM) operation to modify the HIW-BBO algorithm in an algorithm called Self Learned Invasive Weed-Mixed Biogeography based optimization (SLIWMBBO). Thirdly, the performance of the proposed SLIWMBBO algorithm is compared to both the HIW-BBO and the Self Adaptive Cuckoo Search (SACS) optimization algorithms according to a set of 13 benchmark functions. The results of this comparison encourage the application of the SLIWMBBO as an optimization algorithm for solving the complex problems. Lastly, the BBO, HIW-BBO and SLIWMBBO optimization algorithms are used for solving three complex RNP instances and compared to the SACS algorithm. Simulation results of the SLIWMBBO are outstanding and demonstrate its superiority over the compared algorithms.