Dynamic scheduling techniques for heterogeneous computing systems

There has been a recent increase of interest in heterogeneous computing systems, due partly to the fact that a single parallel architecture may not be adequate for exploiting all of a program's available parallelism. In some cases, heterogeneous systems have been shown to produce higher performance for lower cost than a single large machine. However, there has been only limited work on developing techniques and frameworks for partitioning and scheduling applications across the components of a heterogeneous system. In this paper we propose a general model for describing and evaluating heterogeneous systems that considers the degree of uniformity in the processing elements and the communication channels as a measure of the heterogeneity in the system. We also propose a class of dynamic scheduling algorithms for a heterogeneous computing system interconnected with an arbitrary communication network. These algorithms execute a novel optimization technique to dynamically compute schedules based on the potentially non-uniform computation and communication costs on the processors of a heterogeneous system. A unique aspect of these algorithms is that they easily adapt to different task granularities, to dynamically varying processor and system loads, and to systems with varying degrees of heterogeneity. Our simulations are designed to facilitate the evaluation of different scheduling algorithms under varying degrees of heterogeneity. The results show improved performance for our algorithms compared to the performance resulting from existing scheduling techniques.     

Meta-analysis and review of cannabinoids extraction and purification techniques

Projected revenues of cannabis concentrates and extracts in Canada will reach 5 billion dollars, of which infused products will account for half of the total. The pharmacologically active cannabinoids accumulate in the crop's flowers, accounting for as much as 30% of their dry mass, and are absent from the rest of the plant's body. To achieve a cost effective drug formulation requires optimizing cannabis processing techniques. Here, we review the pre-treatment of Cannabis sativa L., its solvent extraction, and the isolation of its active metabolites. We describe traditional extraction processes such as maceration and percolation with organic solvents, but focus on recent green solvent and methods including supercritical fluid extraction (SCFE) and microwave- and ultrasound-enhanced techniques. Furthermore, we report the decarboxylation kinetics to convert tetrahydrocannabinolic acid and cannabidiolic acid and purification-isolation techniques to satisfy regulatory and consumer requirements. Cannabinoids decarboxylate in 10–60 min at 100–150°C. Ethanol and petroleum ether recover up to 90% of the neutral cannabinoids from plant inflorescences, but the crude extracts require further refining as the purity is less than 50%. Propane and butane compressed gas extraction facilitate solvent removal but introduce safety hazards related to flammability. SCFE is the safest solvent-free extraction method with improved terpenoid recovery and $>80\%$ purity. Academic and commercial interest in the field is expected to accelerate in the next decade due to recent changes in regulatory schemes across North America, which will reduce legal and stigmatic barriers to research.     

Investigation of a Near-Perfect Quad-Band Polarization-Insensitive Metamaterial Absorber Based on Dual-T Circular Shaped Resonator Array Designed on a Silicon Substrate for C-, X- and Ku-bands Applications

Silicon - Multi-band metamaterial absorbers (MMAs) are increasingly becoming main devices for many electrical systems. Optimizing the electromagnetic qualities of this type of absorber in the...