A Dynamic Heuristic for the Stochastic Unrelated Parallel Machine Scheduling Problem

This paper addresses the problem of batch scheduling in an unrelated parallel machine environment with sequence dependent setup times and an objective of minimizing the total weighted mean completion time. The jobs\u27 processing times and setup times are stochastic for better depiction of the real world. This is a NP-hard problem and in this paper, new heuristics are developed and compared to existing ones using simulation. The results and analysis obtained from the computational experiments proved the superiority of the proposed algorithm PMWP over the other algorithms presented

Development of a System of Systems Engineering Method

Systems engineers have been facing challenges with the design and analysis of multiple complex systems. System of Systems Engineering has emerged to assist in this challenge with the systemic analysis, design, and transformation of complex metasystems. This paper outlines a proposed method to overcome these challenges, which is grounded in System of Systems Engineering principles and methodology. An overview of System of Systems Engineering will be provided for understanding of its significance and the attempt to complement Systems Engineering efforts in dealing with the aforementioned challenges. Finally, discussion on the proposed method, with respect to complex system analysis, is provided

Efficient protein digestion using highly-stable and reproducible trypsin coatings on magnetic nanofibers

Protein digestion, using an enzyme called trypsin (TR), is one of the key steps in proteomic analysis. The current technology of protein digestion in proteomic analysis is time-consuming, tedious and not automated due to the poor stability and autolysis of trypsin. To improve the protein digestion process, trypsin was immobilized and stabilized on polymer nanofibers entrapping superparamagnetic nanoparticles (magnetic nanofibers, NP-NFs). By electrospinning the homogeneous mixture of superparamagnetic nanoparticles (NPs) and polystyrene-poly(styrene-co-maleic anhydride), NPs could be effectively entrapped within polymer nanofibers, generating magnetically-separable nanofibers with high surface area for trypsin immobilization via the approach of enzyme coatings. Trypsin coatings on magnetic nanofibers (EC-TR/NP-NFs; EC-TR), fabricated via simple attachment of crosslinked trypsin molecules onto NP-NFs, were highly stable and could be recycled via facile magnetic separation. EC-TR showed negligible loss of trypsin activity even after incubation in an aqueous buffer under rigorous shaking (200 rpm) for 80 days, while the control samples of covalently-attached trypsin on NP-NFs (CA-TR/NP-NFs; CA-TR) and free trypsin lost more than 90% of their initial activities within 11 and 6 days, respectively. When highly-stable and magnetically-separable EC-TR was employed for the repetitive digestions of enolase under recycled uses for the duration of 50 days and even after treatment with another protease (chymotrypsin) for 32 h, the performance of enolase digestion was successfully maintained. The use of EC-TR for the enolase digestion in the ultra-sonication system resulted in fast (similar to 10 min) and efficient digestions with reproducible performance under recycled uses.N