A paradigm shift is underway in which the classical materials selection approach in engineering design is being replaced by the design of material structure and processing paths on a hierarchy of length scales for specific multifunctional performance requirements. In this dissertation, the focus is on designing mesoscopic material and product topology?? geometric arrangement of solid phases and voids on length scales larger than microstructures but smaller than the characteristic dimensions of an overall product. Increasingly, manufacturing, rapid prototyping, and materials processing techniques facilitate tailoring topology with high levels of detail. Fully leveraging these capabilities requires not only computational models but also a systematic, efficient design method for exploring, refining, and evaluating product and material topology and other design parameters for targeted multifunctional performance that is robust with respect to potential manufacturing, design, and operating variations. In this dissertation, the Robust Topological Preliminary Design Exploration Method is presented for designing complex multi-scale products and materials by topologically and parametrically tailoring them for multifunctional performance that is superior to that of standard designs and less sensitive to variations. A comprehensive robust design method is established for topology design applications. It includes computational techniques, guidelines, and a multiobjective decision formulation for evaluating and minimizing the impact of topological and parametric variation on the performance of a preliminary topological design. A method is also established for multifunctional topology design, including thermal topology design techniques and multi-stage, distributed design methods for designing preliminary topologies with built-in flexibility for subsequent modification for enhanced performance in secondary functional domains. Key aspects of the approach are demonstrated by designing linear cellular alloys??ered metallic cellular materials with extended prismatic cells?? three applications. Heat exchangers are designed with increased heat dissipation and structural load bearing capabilities relative to conventional heat sinks for microprocessor applications. Cellular materials are designed with structural properties that are robust to dimensional and topological imperfections such as missing cell walls. Finally, combustor liners are designed to increase operating temperatures and efficiencies and reduce harmful emissions for next-generation turbine engines via active cooling and load bearing within topologically and parametrically customized cellular materials.

iv In this study, an Analytic Network Process (ANP) and Data Envelopment Analysis (DEA) based approach was developed in order to measure the performance of customer-based Research and Development projects being executed in T&Uuml / BTAKSAGE, Defense Research and Development Institute, under the Scientific and Technological Research Council of Turkey. In order to evaluate project performance, many criteria, containing various subcriteria were determined. In order to handle the interdependencies among the criteria and the sub-criteria, ANP was used. The ANP model generated in this study is a hybrid model consisting of both a hierarchy and a network. The pairwise comparison matrices that were built up for defining the importance and influences of the criteria/sub-criteria in the ANP model were formed as interval judgments from a group decision making process, based on data obtained from a questionnaire conducted among the experts in the Institute. From the interval pairwise comparison matrices, weight intervals for the sub-criteria were determined and these bounds were used as assurance region constraints in a super-efficiency DEA model, through which the project ranking was obtained. Taking into consideration that there may occur some missing values in some projects for some of the sub-criteria, the superefficiency DEA model was extended to handle missing data. The model was applied to a real case study on performance evaluation of the ongoing customer-based projects in the Institute. For comparison purposes, the case study was also solved by two other approaches.

<p>The purpose of this thesis is to develop a model for assessing cost effectiveness of applying lean tools. The model consists of eight phases: it starts by understanding customers' requirements using Voice of Customer (VOC) and Quality Function Deployment (QFD) tools. In phase 2, the current state of plant is assessed using lean profile charts based on Balanced Scorecard (BSC) measures. In phase 3 and phase 4, identification of critical problem(s) and generating of improvement suggestion(s) are performed. Phase 5 provide evaluation of the cost effectiveness of implementing the suggested lean methods based on life cycle cost analysis (LCCA) and phase 6 prefers the right alternative based on multiple criteria decision making (MCDM). In phase 7 the selected alternative is supposed to be implemented and finally the user should monitor and control the process to make sure that the improvement is going as planned. The model was verified successfully using a case study methodology at one Swedish sawmill called Södra Timber in Ramkvilla, one part of Södra group. Results obtained from the study showed that the production and human resources perspectives are the most critical problem areas that need to be improved. They got the lowest scores in the lean profile, 63% and 68%, respectively. Using value stream mapping (VSM) it was found that the non value added (NVA) ratios for the core and side products are 87.4% and 90.4%, respectively. Using the model, three improvement alternatives were suggested and evaluated using LCCA and MCDM. Consequently, implementing 5S got the highest score, second came redesigning the facility layout. However, it was estimated that 4.7 % of NVA for the side product would be reduced by redesigning the facility layout. The recommendations were suggested for the company to improve their performance. The novelty of the thesis is based on the fact that it addresses two main issues related to lean manufacturing: firstly, suggesting lean techniques based on assessment of lean profile that is based on BSC and QFD, and secondly assessing the cost effectiveness of the suggested lean methods based on LCCA and MCDM. This thesis provides a generalized model that enables the decision-maker to know and measure, holistically, the company performance with respect to customer requirements. This will enable the company to analyze the critical problems, suggest solutions, evaluate them and make a cost effective decision. Thus, the company can improve its competitiveness.</p>

Gyvenant šių dienų Lietuvoje jau neužtenka buityje ar gamyboje susidarančių atliekų tvarkyti taip kaip buvome įpratę anksčiau. Kitaip tvarkyti atliekas skatina Europos Sajungos ir kiti tarptautiniai įsipareigojimai. Gerėjant gyventojų gyvenimo sąlygoms, išaugus vartojimui, žmonės ypač daug perka ir keičia buitinės technikos, bei kitų prekių, kurių pasekoje susidaro įvairių atliekų. Lietuvoje pasirinkta strategija įdiegiant regioninę atliekų tvarkymo sistemą, nors žvelgiant į atskiras savivaldybes, galima teigti, kad kai kuriose ši, regioninė atliekų tvarkymo sistema nėra optimaliausias variantas. Regioninės atliekų tvarkymo sistemos diegimui, apskričių savivaldybės yra įkūrusios regiono atliekų tvarkymo centrus, kurių vienas artimiausiu tikslų tai senų sąvartynų uždarymas. Kaip tik sąvartynų uždarymo klausimui spręsti galime panaudoti sprendimų paramos sistemas, o būtent, daugiakriterinę analizę. Daugiakriterinei analizei atlikti gali būti pasitelkiama keletas kompiuterinių programų, tokių kaip HYPSE ar Sprendimų analizės modulis (DAM), kurią šiame darbe ir naudojame. Sprendimų analizės modulio panaudojimui buvo nustatyti tam tikri kriterijai, o alternatyva tai kiekvienas Jurbarko rajono sąvartynas. Kiekvienas kriterijus apibūdina kiekvieną alternatyvą (sąvartyną). / These days there isn‘t enough just taking care of communal or industry waste as we all are accustomed in Lithuania. The different waste managing is Europian Union and other international commit for Lithuania. Better everyday life in Lithuania brings bigger usage, that makes people to buy more life eguipment and other everyday goods, which brings to new waste. There is a regional waste managing system strategy in Lithuania, which isn't very optimal system for some of the Lithuanian municipalities. For this purpose district local governments established regional waste management centers, whose one of the first tasks is to close old landfills. For this problem to solve we will use decision making preferences, and that is multiple criteria decision analysis. There is several computer software for applying multiple criteria decision analysis, just like HYPSE and Decision analysis module (DAM), wich one we used in this study. For use of Decision analysis module we defined criteria, and alternative was Jurbarkas district landfills. Every criteria characterizes every alternative (landfill).

The aim of the disertation is to improve the efficiency of the of the refurbishment process of the public buildings by using methods of multiple criteria analysis, the developed model for integrated analysis of the negotiations process for refurbishment of buildings and the Multiple Criteria Decision Support System for Refurbishment of Public Buildings developed on the basis of these models.

The aim of the dissertation is to improve the efficiency of the refurbishment process of public buildings by using methods of multiple criteria analysis, the developed model for integrated analysis of the lifecycle of a public building, the model for integrated analysis of the negotiations process for refurbishment of buildings and the Multiple Criteria Decision Support System for Refurbishment of Public Buildings developed on then basis of these models.

Object of the research. The research object includes a CCA and a model of a web-based decision support system developed by integrating basic knowledge in the sphere of construction management, civil law, mathematical methods and advanced computer technologies; the model system enables effective implementation of aims of various parties of a CCA. Aim and tasks of the work. The main aim of the dissertation is to develop a theoretical model of a web-based decision support system for legal regulation of CCAs, taking in to consideration principles of construction management, improvement of effectiveness of legal regulation of CCAs, employing computer technologies, theoretical assumptions related to development of e-business systems, and etc. In order to make an effective theoretical model of a web-based decision support system for legal regulation of CCAs, the following tasks are stated: • To analyse importance of e-business in improvement of effectiveness of preparation of CCAs. • To make a feasibility study of the potential of e-business principles, of factors determining effectiveness and of decision support measures in preparation of CCAs. • To analyse principles of operating decision support systems intended for construction, law and agreement preparation. • To prepare several models for evaluation of CCAs and to select the best. • To analyse the potential of application of currently used multiple criteria analysis methods in a web-based decision support system for legal... [to full text]

During the design process for an aerospace vehicle, decision-makers must have an accurate understanding of how each choice will affect the vehicle and its performance. This understanding is based on experiments and, increasingly often, computer models. In general, as a computer model captures a greater number of phenomena, its results become more accurate for a broader range of problems. This improved accuracy typically comes at the cost of significantly increased computational expense per analysis. Although rapid analysis tools have been developed that are sufficient for many design efforts, those tools may not be accurate enough for revolutionary concepts subject to grueling flight conditions such as transonic or supersonic flight and extreme angles of attack. At such conditions, the simplifying assumptions of the rapid tools no longer hold. Accurate analysis of such concepts would require models that do not make those simplifying assumptions, with the corresponding increases in computational effort per analysis. As computational costs rise, exploration of the design space can become exceedingly expensive. If this expense cannot be reduced, decision-makers would be forced to choose between a thorough exploration of the design space using inaccurate models, or the analysis of a sparse set of options using accurate models. This problem is exacerbated as the number of free parameters increases, limiting the number of trades that can be investigated in a given time. In the face of limited resources, it can become critically important that only the most useful experiments be performed, which raises multiple questions: how can the most useful experiments be identified, and how can experimental results be used in the most effective manner? This research effort focuses on identifying and applying techniques which could address these questions. The demonstration problem for this effort was the modeling of a reusable booster vehicle, which would be subject to a wide range of flight conditions while returning to its launch site after staging. Contour-based sampling, an adaptive sampling technique, seeks cases that will improve the prediction accuracy of surrogate models for particular ranges of the responses of interest. In the case of the reusable booster, contour-based sampling was used to emphasize configurations with small pitching moments; the broad design space included many configurations which produced uncontrollable aerodynamic moments for at least one flight condition. By emphasizing designs that were likely to trim over the entire trajectory, contour-based sampling improves the predictive accuracy of surrogate models for such designs while minimizing the number of analyses required. The simplified models mentioned above, although less accurate for extreme flight conditions, can still be useful for analyzing performance at more common flight conditions. The simplified models may also offer insight into trends in the response behavior. Data from these simplified models can be combined with more accurate results to produce useful surrogate models with better accuracy than the simplified models but at less cost than if only expensive analyses were used. Of the data fusion techniques evaluated, Ghoreyshi cokriging was found to be the most effective for the problem at hand. Lastly, uncertainty present in the data was found to negatively affect predictive accuracy of surrogate models. Most surrogate modeling techniques neglect uncertainty in the data and treat all cases as deterministic. This is plausible, especially for data produced by computer analyses which are assumed to be perfectly repeatable and thus truly deterministic. However, a number of sources of uncertainty, such as solver iteration or surrogate model prediction accuracy, can introduce noise to the data. If these sources of uncertainty could be captured and incorporated when surrogate models are trained, the resulting surrogate models would be less susceptible to that noise and correspondingly have better predictive accuracy. This was accomplished in the present effort by capturing the uncertainty information via nuggets added to the Kriging model. By combining these techniques, surrogate models could be created which exhibited better predictive accuracy while selecting the most informative experiments possible. This significantly reduced the computational effort expended compared to a more standard approach using space-filling samples and data from a single source. The relative contributions of each technique were identified, and observations were made pertaining to the most effective way to apply the separate and combined methods.

Praktikoje dažnai tenka spręsti sudėtingus daugiakriterinius optimizavimo uždavinius, kai kriterijai būna prieštaringi, o galutinis apsisprendimas priklauso nuo sprendimų priėmėjo. Kai sprendimų priėmėjas dalyvauja sprendimo procese interaktyviai, tai jis gali koreguoti prioritetus ir siekiamus tikslus uždavinio sprendimo eigoje, kas įgalina spęsti uždavinius, turinčius daug kriterijų ir apribojimų. Be to, sprendimo priėmėjui svarbu gauti sprendinius iš visos Pareto aibės. Interaktyviam uždavinių sprendimui būtina sprendimų paramos sistema, kurios grafinė sąsaja yra pritaikyta sprendžiamam uždaviniui. Šio darbo tyrimų sritis yra interaktyvus daugiakriterinių optimizavimo uždavinių sprendimas bei sprendimų paramos sistemos. Disertacijoje nagrinėjant daugiakriterinio optimizavimo metodus, didesnis dėmesys skirtas metodams, užtikrinantiems gaunamų sprendinių tolygų pasiskirstymą Pareto aibėje bei interaktyviems metodams. Pasiūlytas ir ištirtas daugiakriterinių optimizavimo uždavinių sprendimo būdas, leidžiantis spręsti daugiakriterinius optimizavimo uždavinius interaktyviai ir užtikrinantis gaunamų sprendinių tolygų pasiskirstymą Pareto aibėje. Sukurta ir ištirta interaktyvi daugiakriterinių optimizavimo uždavinių sprendimų paramos sistemą, apjungianti pasiūlytą optimizavimo uždavinių sprendimo būdą, sprendimo proceso vizualizavimą ir jo lygiagretinimą. Taip pat pasiūlyta sprendimo strategija, pagal kurią sprendžiant daugiakriterinį optimizavimo uždavinį pasitelkiamas... [toliau žr. visą tekstą] / In practice, optimization problems are often multiple criteria. The criteria are usually contradictory, so the final decision depends on a decision maker. When the problem is solved interactively, the decision maker can change his/her preferences in decision process. Moreover, it is important to obtain solutions from the whole Pareto front. A decision support system adapted to the specific of the problem is essential for solving multiple criteria optimization problems interactively. The objects of research are multiple criteria optimization problems, interactive methods for solving these problems, interactive decision support systems, and application of parallel computing in decision support systems. Multiple criteria optimization methods are analyzed in the dissertation. The focus of attention is the methods for a uniform distribution of solutions on the Pareto front as well as the interactive methods. An interactive way for solving multicriteria optimization problems, which finds alternative solutions uniformly distributed on the Pareto front is proposed and investigated in this dissertation. An interactive decision support system which integrates the created interactive solving way, the decision process visualization and parallelization for multiple criteria optimization is developed. The solving strategies, when a multiple criteria optimization problem is solved interactively, using a computer cluster are developed and compared experimentally. The time required for a... [to full text]

In practice, optimization problems are often multiple criteria. The criteria are usually contradictory, so the final decision depends on a decision maker. When the problem is solved interactively, the decision maker can change his/her preferences in decision process. Moreover, it is important to obtain solutions from the whole Pareto front. A decision support system adapted to the specific of the problem is essential for solving multiple criteria optimization problems interactively. The objects of research are multiple criteria optimization problems, interactive methods for solving these problems, interactive decision support systems, and application of parallel computing in decision support systems. Multiple criteria optimization methods are analyzed in the dissertation. The focus of attention is the methods for a uniform distribution of solutions on the Pareto front as well as the interactive methods. An interactive way for solving multicriteria optimization problems, which finds alternative solutions uniformly distributed on the Pareto front is proposed and investigated in this dissertation. An interactive decision support system which integrates the created interactive solving way, the decision process visualization and parallelization for multiple criteria optimization is developed. The solving strategies, when a multiple criteria optimization problem is solved interactively, using a computer cluster are developed and compared experimentally. The time required for a... [to full text] / Praktikoje dažnai tenka spręsti sudėtingus daugiakriterinius optimizavimo uždavinius, kai kriterijai būna prieštaringi, o galutinis apsisprendimas priklauso nuo sprendimų priėmėjo. Kai sprendimų priėmėjas dalyvauja sprendimo procese interaktyviai, tai jis gali koreguoti prioritetus ir siekiamus tikslus uždavinio sprendimo eigoje, kas įgalina spęsti uždavinius, turinčius daug kriterijų ir apribojimų. Be to, sprendimo priėmėjui svarbu gauti sprendinius iš visos Pareto aibės. Interaktyviam uždavinių sprendimui būtina sprendimų paramos sistema, kurios grafinė sąsaja yra pritaikyta sprendžiamam uždaviniui. Šio darbo tyrimų sritis yra interaktyvus daugiakriterinių optimizavimo uždavinių sprendimas bei sprendimų paramos sistemos. Disertacijoje nagrinėjant daugiakriterinio optimizavimo metodus, didesnis dėmesys skirtas metodams, užtikrinantiems gaunamų sprendinių tolygų pasiskirstymą Pareto aibėje bei interaktyviems metodams. Pasiūlytas ir ištirtas daugiakriterinių optimizavimo uždavinių sprendimo būdas, leidžiantis spręsti daugiakriterinius optimizavimo uždavinius interaktyviai ir užtikrinantis gaunamų sprendinių tolygų pasiskirstymą Pareto aibėje. Sukurta ir ištirta interaktyvi daugiakriterinių optimizavimo uždavinių sprendimų paramos sistemą, apjungianti pasiūlytą optimizavimo uždavinių sprendimo būdą, sprendimo proceso vizualizavimą ir jo lygiagretinimą. Taip pat pasiūlyta sprendimo strategija, pagal kurią sprendžiant daugiakriterinį optimizavimo uždavinį pasitelkiamas... [toliau žr. visą tekstą]