A literature review on the use of expert opinion in probabilistic risk analysis

Risk assessment is part of the decision making process in many fields of discipline, such as engineering, public health, environment, program management, regulatory policy, and finance. There has been considerable debate over the philosophical and methodological treatment of risk in the past few decades, ranging from its definition and classification to methods of its assessment. Probabilistic risk analysis (PRA) specifically deals with events represented by low probabilities of occurring with high levels of unfavorable consequences. Expert judgment is often a critical source of information in PRA, since empirical data on the variables of interest are rarely available. The author reviews the literature on the use of expert opinion in PRA, in particular on the approaches to eliciting and aggregating experts'assessments. The literature suggests that the methods by which expert opinions are collected and combined have a significant effect on the resulting estimates. The author discusses two types of approaches to eliciting and aggregating expert judgments-behavioral and mathematical approaches, with the emphasis on the latter. It is generally agreed that mathematical approaches tend to yield more accurate estimates than behavioral approaches. After a short description of behavioral approaches, the author discusses mathematical approaches in detail, presenting three aggregation models: non-Bayesian axiomatic models, Bayesian models, andpsychological scaling models. She also discusses issues of stochastic dependence.Health Monitoring&Evaluation,ICT Policy and Strategies,Public Health Promotion,Enterprise Development&Reform,Statistical&Mathematical Sciences,ICT Policy and Strategies,Health Monitoring&Evaluation,Statistical&Mathematical Sciences,Science Education,Scientific Research&Science Parks

Inventory Control at AQ Electric Suzhou

This report details the process and result of developing a mathematical inventory control model to be use by AQ Electric Suzhou. The mathematical model was written in Microsoft Excels inherent programming language Visual Basic and utilizes printouts such as sales history, bill of materials, component data etc. from AQ Electric Suzhous ERP system Monitor to derive a demand history for each component. Each component is then given a compound Poisson lead time demand distribution with an optimization of reorder point in a (R,Q) continuous review inventory system with regards to service level and maximum inventory constraints. The results were that AQ Electric Suzhou would find it difficult to achieve the target on time delivery and target inventory turn rate simultaneously without changing input parameters such as minimum order quantities and lead times

Constrained activity sequencing

Mnoho rozvrhovacích problémů lze považovat za problémy s hledáním posloupností aktivit splňujících určité podmínky a omezení. Typickým příkladem je rozvrhování letů v leteckém průmyslu, kde úlohou je přiřazení segmentů letů a servisních aktivit k jednotlivým letadlům. Tato diplomová práce se zaměřuje na hledání takovýchto omezených posloupností aktivit. Cílem práce je navrhnout formální model problému, včetně přesné specifikace podmínek a účelové funkce, schopný najít (sub)optimální posloupnosti aktivit. Navrhovaný model je založen na technikách Programování s omezujícími podmínkami.Many scheduling problems can be seen as activity sequencing problems, where the activity sequence in demand satisfies certain constraints. A typical example is scheduling in the airline industry where the task is to assign to each aircraft a segment of flight and nonflight activities while guaranteeing certain required properties. This diploma thesis deals with such type of constrained activity sequencing. The aim is to propose a formal model of the problem, including specification of all constraints and objectives, capable of finding (near)optimal sequences of activities. The proposed model is based on Constraint programming techniques.Department of Theoretical Computer Science and Mathematical LogicKatedra teoretické informatiky a matematické logikyFaculty of Mathematics and PhysicsMatematicko-fyzikální fakult