The genetic algorithm paradigm is a well-known heuristic for solving many problems in science and engineering in which candidate solutions, or “individuals”, are manipulated in ways analogous to biological evolution, to produce new solutions until one with the desired quality is found. As problem sizes increase, a natural question is how to exploit advances in distributed and parallel computing to speed up the execution of genetic algorithms. This thesis proposes a new distributed architecture for genetic algorithms, based on distributed storage of the individuals in a persistent pool. Processors extract individuals from the pool in order to perform the computations and then insert the resulting individuals back into the pool. Unlike previously proposed approaches, the new approach is tailored for distributed systems in which processors are loosely coupled, failure-prone and can run at different speeds. Proof-of-concept simulation results are presented for four benchmark functions and for a real-world Product Lifecycle Design problem. We have experimented with both the crash failure model and the Byzantine failure model. The results indicate that the approach can deliver improved performance due to the distribution and tolerates a large fraction of processor failures subject to both models.

Products make substantial impact on environment. Design for Environment (DfE) is an approach to design where all the environmental impacts of a product are considered over entire products life. Since over 80% of the product costs are committed during the early stages, design can play a central role in reducing this environmental overloading by product. However, unlike cost and performance, use of environmental criteria and DfE is far from part of mainstream designing. Individual guidelines often exist for DfE but these are not integrated with design tools. There is a need for capture of the rationale in design process as a know how backup for later use. Life Cycle Assessment (LCA) is currently the most promising and scientifically proven technique for estimating environmental impacts of a product during its lifecycle. Current LCA tools are not well integrated with design process and CAD tools. Consequently, there is a need for an LCA tool integrated into the natural design process that can be applied to early as well as detailed design stages. Detailed LCA is critically dependent on high volumes of product specific data, time consuming, often unaffordable and used after the detailed stages of design. Current approximate LCA methods are either incomplete, inaccurate or require prior knowledge of what data is important There is substantial uncertainty involved in the environmental impact calculations in LC. While Literature discusses uncertainty of impact data, there is no discussion on how to calculate and represent the total uncertainty in the potential impact of a product proposal at any given stage in design with respect to LCA. There is a need for a method that can aid in decision making by supporting quantitative comparison of available alternatives to identify the best alternative, under uncertain information about alternatives. Often the likely performance, cost or environmental impacts of a product proposal could be estimated only with certain confidence, which may vary from one proposal to another. The overall objective of this thesis is to “Develop a support to the designers using which they can develop environmentally friendly product lifecycles in much the same way as they currently design products, at all stages of their design, while reusing information from their past design activities”. For this the specific objectives are to: 1.Understand how designers currently design products and what they need for developing environmentally friendly product design. 2.Develop a holistic framework for both generation and evaluation of environmentally friendly life cycle proposals. 3. Capture rationale as part of the design process. 4. Estimate uncertainty in the environmental impact assessment during design. 5. Evaluate product lifecycle proposals with multiple criteria under uncertainty. 6. Integrate design process with environmental impact assessment. 7. Apply environmental impact assessment through the design process. From the descriptive studies we found that there is substantial difference in the environmental impact among products having the same functionality generated during the same design process. Analysis of industrial products available in the market show similar results. This means that design can substantially affect the impact created by a product. In our studies, designers did not consider environmental impact as a criterion in evaluation and we also identified the typical activities performed by designers during An Interactive Support for Developing Environmentally Friendly Product Lifecycles designing that must be allowed, supported or taken into account while developing a support for environmentally friendly product lifecycle design (EFPLD). The requirements of the designer for support are: tools should be proactive, easy to learn, understand and use, allow understanding of design rationale, act as a checklist, reduce total time, store knowledge and experience as know‐how backup, useful in all stages of design, not require too much extra effort for analysis, integrated to CAD, aid in trade off between choices, show uncertainty analysis, aid in analysis & improvement, and consider all lifecycle phases. A holistic framework, ACLODS (is a acronym of the six dimensions) constituting the following six dimensions: a) Activities, b) Criteria, c) Lifecycle phases, d) Outcomes, e) Design stages, and f) Product Structure was proposed for development of environmentally friendly product lifecycle designs. Through descriptive studies we found mainly 4 categories and associated sub categories of uncertainty in information with respect to LCA in design. The four categories are uncertainty in product structure, lifecycle phases, data quality, and methodological choices. The sub categories are assemblies, sub- assemblies, parts, relations, and features in product structure, material, production, distribution, usage, and after‐usage in lifecycle phases, temporal relevance, spatial relevance and sample size in data quality, and temporal relevance, spatial relevance, and comprehensiveness in methodological choices. At any point of time, uncertainty in information available is an accrual of the combination of the individual uncertainties. A method called confidence weighted objectives method is developed to compare the whole lifecycle of product proposals using multiple evaluation criteria under various levels of uncertainty. It is compared with normal weighted objectives method and found to be better since it estimates the overall worth of proposal nd confidence on the estimate, enabling deferment of decision making when decisions cannot be made using current information available. A new integrated platform IDEA‐SUSTAIN is developed in this thesis for supporting synthesis in product development on a commercial CAD workspace, while also aiding automated capture and storage of the rationale behind the decisions for retrieval whenever required during design. It is extended to support life cycle assessment of product proposals created by automatically extracting the information already stored while designing and ask for other information required to model the lifecycle without much extra effort from the designer. Then it uses the method for uncertainty reasoning developed also as a part of this research to estimate the level of confidence on the impact value owing to the incompleteness in knowledge available. The estimation is possible at part, assembly or product levels, for a single lifecycle phase or multiple phases. Using in‐house design exercises and feedback questionnaire evaluation of support is done. The usage of Idea‐Sustain has been found to be the best for both generation and evaluation of product proposals. The two computer aided tools – software (LCA) and Idea-Sustain-are compared with each other for fulfilling the functional requirements by analysing the feedbacks given by the designers on these tools against these requirements. Idea‐Sustain fulfilled well most of the requirements while the software (LCA) fulfilled only some of the needs, that too less effectively.