Optimization tasks in practice have multifaceted challenges as they are often black box, subject to multiple equality and inequality constraints and expensive to evaluate. The efficiency of a... Show moreOptimization tasks in practice have multifaceted challenges as they are often black box, subject to multiple equality and inequality constraints and expensive to evaluate. The efficiency of a constrained optimizer has a crucial importance when it comes to selecting a suitable method for solving real-world optimization problems from industry with strict resource limitations. The primary concern of this work is to develop new black box optimization algorithms which are generic enough to successfully handle a broad set of constrained optimization problems (COPs) efficiently and without requiring apriori parameter tuning for different classes of the problems. To achieve this goal we benefit from two main conceptual components in the development of new constrained solvers: 1. utilizing surrogate modeling techniques to save real function evaluations, 2. automatically adjusting sensitive problem-dependent parameters based on the information gained about the problems during the optimization procedure. This work eventuated in the development of two surrogate-assisted constrained solvers: SACOBRA and SOCU. It turns out that SACOBRA outperforms most other COP-solvers in solving the well-known G-problem suite and MOPTA08 (a COP from automotive industry), if the number of function evaluations is strongly limited. Show less
Including modelling as part of software development appears to have various benefits. Why then is it that not all companies use software modelling? One of the main reasons is that it requires up... Show moreIncluding modelling as part of software development appears to have various benefits. Why then is it that not all companies use software modelling? One of the main reasons is that it requires up-front investments. From an economic point of view, any type of investment must be justified in terms of how much payback there will be at a later stage. This being the case, in the context of software projects, investment in modelling should be justified by benefits, such as improved productivity and improved product quality, which can be seen later during software development or maintenance. When such benefits are not tangible or foreseeable, modelling becomes a practice without clear added value for the system being developed. The problem, therefore, is how we can investigate and prove whether or not modelling, or some specific characteristics of modelling, provide any benefits during software development and maintenance. As long as this question remains unanswered, it will be difficult to motivate and justify modelling activities in real software projects. This thesis therefore contributes to partially answering these open questions by focusing the empirical research on the benefits of using UML modelling during software maintenance. Show less
With the rapid development of electronic commerce, logistics management has become more and more important in the procedure of supply chain management. The goal of logistics management is to... Show moreWith the rapid development of electronic commerce, logistics management has become more and more important in the procedure of supply chain management. The goal of logistics management is to satisfy the demands of customers while minimizing the use of resources of the whole process in logistics management from the point of origin to the point of consumption. The logistics management technology has been widely used in the field of engineering and contributes to reducing the total logistics cost. In this thesis, we focus on algorithms based on nature-inspired paradigms to solve dynamic logistics management problems. Results show that the proposed multiple ant system algorithm and the multi-objective cooperative particle swarm algorithm are able to produce good solutions for the vehicle routing problems and inventory routing problems not only in theory but also in practice. Show less
As the de facto industry standard for software modeling, the Unified Modeling Language (UML) is used widely across various IT domains. UML__s wide acceptance is partly because the language offers... Show moreAs the de facto industry standard for software modeling, the Unified Modeling Language (UML) is used widely across various IT domains. UML__s wide acceptance is partly because the language offers flexibility and freedom in modeling software systems: 1) UML provides an extensive set of modeling notations that can be used to model various concepts; 2) UML can be used both in a casual and formal manners. In the context of model-driven software development, the degree of freedom in which UML is used raises an important issue related to model quality. Different styles and rigors in using UML affect the quality of the resulting models. It is then logical to think that the level of quality of the UML model may affect the quality of the resulting software. This thesis reports on a series of empirical studies performed to address a pivotal question concerning the benefits of UML modeling in software development, particularly from a quality perspective. The results of these empirical studies show that the use of UML provides benefits in terms of increased quality and productivity in software development. The availability of UML models also allows early prediction of defects in software systems. Such prediction is potentially useful for identifying and fixing defects early during software development, and for prioritizing testing. Show less
