68 research outputs found
Mathematics in Software Reliability and Quality Assurance
This monograph concerns the mathematical aspects of software reliability and quality assurance and consists of 11 technical papers in this emerging area. Included are the latest research results related to formal methods and design, automatic software testing, software verification and validation, coalgebra theory, automata theory, hybrid system and software reliability modeling and assessment
Integrated feedstock optimisation for multi-product polymer production
Thesis (PhD)--Stellenbosch University, 2022.ENGLISH ABSTRACT: A chemical complex can have multiple value chains, some of which may
span across geographical locations. Decisions regarding the distribution
of feedstock and intermediate feedstock to different production units can
occur at different time intervals. This is highlighted as two problems, a
feedstock distribution problem and an intermediate feedstock distribution
problem. Unexpected events can cause an imbalanced value chain which
requires timely decision-making to mitigate further adverse consequences.
Scheduling methods can provide decision support during such events. The
purpose of this research study is to develop an integrated decision support
system which handles the two problems as a single problem and maximises
profit in the value chain for hourly and daily decision-making. A high-level
DSS architecture is presented that incorporates metaheuristic algorithms
to generate production schedules for distribution of feedstock through the
value chain. The solution evaluation process contains a balancing period
to enable the application of metaheuristics to this type of problem and
a novel encoding scheme is proposed for the hourly interval problem. It
was found that metaheuristics algorithms can be used for this problem
and integrated into the proposed decision support system.AFRIKAANSE OPSOMMING: ’n Chemiese kompleks kan verskeie waardekettings hê, waarvan sommige
oor geografiese gebiede strek. Besluite rakende die verspreiding van grondstowwe en intermediêre grondstowwe na verskillende produksie-eenhede
kan op verskillende tydsintervalle plaasvind. Dit word uitgelig as twee
probleme: ’n probleem met die verspreiding van grondstowwe en ’n intermediêre grondstowwe verspreidingsprobleem. Onverwagte gebeure kan
’n ongebalanseerde waardeketting veroorsaak wat tydige besluitneming
benodig om verdere gevolge te versag. Beplanningsmetodes kan ondersteuning bied tydens sulke geleenthede. Die doel van hierdie navorsingstudie was om ’n geïntegreerde stelsel vir besluitnemingsondersteuning oor die twee probleme as een probleem te ontwikkel, wat wins in die
waardeketting vir uurlikse en daaglikse besluitneming maksimeer. ’n Hoëvlak DSS-argitektuur word aangebied met metaheuristieke om produksieskedules vir verspreidingstowwe deur die waardeketting te genereer.
Die oplossingsevalueringsproses bevat ’n balanseerperiode om die metaheuristiek op hierdie tipe probleme toe te pas, en ’n nuwe koderingskema
word voorgestel vir die uurlikse intervalprobleem. Die gevolgtrekking word gemaak dat metaheuristieke vir hierdie probleem gebruik kan word
en ge¨ıntegreer kan word in die voorgestelde ondersteuningsstelsel vir besluitneming.Doctora
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