• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 59
  • 29
  • 23
  • 10
  • 7
  • 6
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 149
  • 149
  • 130
  • 32
  • 28
  • 23
  • 21
  • 20
  • 19
  • 18
  • 17
  • 17
  • 16
  • 15
  • 15
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Optimalizace konstrukce zvedače dutinky spřádacího stroje / Optimalization construction tube lifter of spinner machine

Jeník, Jan January 2012 (has links)
The first part of this thesis describes the current technologies of mechanical spin-ning. This is a ring, rotor and air-jet spinning. The product of spinning machines is yarn, the basic material for production textile. The next section describes in detail the current state of the node manipulator lifter tube on spinning machine TORNADO J20, by concern RIETER. It describes the structure, kinematics, duty cycle and requirements for the manipulator. The following optimization options which are described more options for solutions of individual functions of the manipulator, on the end is selected by multi-criteria analysis. The best solution that is elaborate in the next section. The author has created 3-D model optimized lifter tube. Positioning mechanism maintains the current kinematics, it is very similar. But gripper was designed as a passive, thus reduce the load positioning mechanism. Optimization was performed primarily to reduce overall production costs and to reduce weight manipulator. The conclusion is a comparison of current and new solutions. There are also eco-nomic recovery to.
72

Studie obchvatu Valašského Meziříčí / The study bypass Valasske Mezirici

Horka, Pavel January 2017 (has links)
The subject of the thesis is to elaborate the search study of the west four-line bypass of the town of Valašské Meziříčí. The reasons for constructing the bypass are to divert heavy transit traffic, to increase safety in the town and to reduce the negative impacts of transport. Road is designed as a category R21,5/100. Three Seven direction solutions were designed of which one was chosen by multi-criteria analysis for further solution.
73

Preliminary design and multi-criteria analysis of solutions for widening an existing concrete bridge : Case of the Bridge of Chaillot in Vierzon (France)

Fline, Pierre January 2011 (has links)
Europe experienced the destruction of numerous infrastructures during World War II, followed by a reflation and a strong economic growth during the next two decades allowing a more perennial and durable situation. A classical bridge lasting in general around 80 years, one should observe that these constructions built after the war will have to be either replaced either seriously strengthened in a few years. Besides, since the needs also vary over time, transportation infrastructures built during those years might not be adapted to the actual needs anymore – some bridges might thus have to be widened. A case study has been chosen in order to simulate under which conditions the widening of such a bridge can be performed. This road bridge, located in Vierzon in France, is rather simple since it is made of simply supported prestressed concrete beams and of reinforced concrete piers. It has been chosen in particular for its reduced size – three spans of 30 m each and two road lanes – that corresponded well to this project. Based on some data provided when the bridge was initially built and on a visual inspection, this project suggests six technical solutions to double the actual amount of lanes. An evaluation of the performance of the solutions according to three criteria – durations of works, cost of the works, and environmental impact – is made in order to give recommendations regarding the optimal solution. The results show that in spite of being installed quickly, adding steel beams is more expensive and has a greater impact on the environment than adding prestressed concrete beams. Regarding the modification of piers, the solution suggesting widening the existing piers is preferable than adding new extra piers according to all the criteria. Consequently, among all the solutions analysed, the optimal one is also the simplest one. Finally, the limits of the study and some suggestions for improvements are indicated.
74

Interdisciplinary and interspatial discrepancies in urban planning : a multi-actor-multi-criteria analysis of the effects of densification on accessibility and sustainability

van der Ham, Jelmer January 2022 (has links)
Density has increasingly been used as a strategy by urban planners to increase accessibility and urban sustainability. Particularly, it has been opted as a tool to achieve sustainable development goal 11 ‘inclusive, safe, resilient, and sustainable cities and human settlements’. Though densification is considerably impactful in realising resource efficiency and transport benefits, its effects are too multi-lateral to be used as a linear tool to realise accessibility and sustainability. This is both caused by the assume d knowledge-practice gap between academics and urban planners, as well as the complexity of interspatial collaboration between local and global practitioners. Particularly, the universal application of sustainable development goal 11 and the top-down approaches to evaluate performance in achieving sustainability hinder strategic interspatial integration. Fostering interspatial and interdisciplinary collaboration would require establishing a holistic indicator framework that acts as a foundation for contextualised project appraisal. Relevant topics were identified and validated by expert opinion to establish such an operationalised indicator framework that could be used as a foundation for practitioners to evaluate the effects of densification projects on accessibility and sustainability. To identify what topics planning actors across spatial scales (i.e., local, regional, and national)and between disciplines (i.e., academia and practice) value differently, the priorities of topics presented in the indicator list were compared by various stakeholders from the Greater Gothenburg region. Comparing priorities and identifying disparities was done using the methodological framework of the Analytical Hierarchy Process. More specifically, a multi-actor-multi-criteria analysis was used to compare priorities. The differences between responses showed that the gap between knowledge and adaptation might be smaller than initially suspected. Differences in priorities between planning actors across spatial scales shows interspatial discrepancies in mainly the valuation of public transport, urban services, and biodiversity conservatio n. Furthermore, notable differences in prioritisation by singular actors illustrate the need to qualitatively inquire certain topics further, including the role of inter-urban employment on transport networks, the incorporation of social factors in quantitative appraisal, the capacity of small municipalities to incorporate contextualised biodiversity conservation, and the role of a varied accommodation supply on metropolitan housing shortage.
75

En fallstudie av olika typer ytterväggsisolering och dess påverkan på hållbar samhällsbyggnad / A case study of different types of exterior wall insulations and their impact on sustainable society

Nissen, Martin, Alameri, Zain January 2022 (has links)
Introduction: Sweden's climate creates several challenges to achieve habitable indoor climate. In Sweden, it is most common for detached houses of wooden construction to use mineral wool or wood fibre to insulate the exterior walls. While mineral wool and wood fibre are the most popular choices, there are several other alternative insulation materials that can be beneficial. The thesis deals with four insulation materials where stone wool and wood fibre are pitted against the more modern materials PIR and PUR to investigate which is most advantageous with the help of life cycle analysis, life cycle cost analysis and energy use in production, installation and end of life. The three criteria are then summed up in a multi-criteria analysis to decide which material is most beneficial.  Method: To reach a result, a literature study and case study is conducted with life cycle analysis, life cycle cost analysis and energy use. The life cycle assessment answers question 1, the life cycle cost analysis answers question 2 and the multi-criteria analysis answers question 3.  Results & Analysis: Four different insulation materials in a wood-constructed wall were studied where PIR and PUR were considered in two different forms, onewith the same U-value as the stone wool and wood fibre, the other with the same thickness as the stone wool and wood fibre. The different variants are studied using the different criteria in the multi-criteria analysis. The material that has the best environmental impact in the life cycle analysis is wood fibre and then the thin PIR, stone wool, thick PIR, thin PUR and lastly thick PUR. In the life cycle cost analysis, the stone wool is most price efficient, then wood fibre, thin PIR, thick PIR, thin PUR and the most expensive price has the thick PUR. The material with the least energy use throughout the life of the material is wood fibre which is 100 % recyclable, after the wood fibre comes stone wool, thin PIR, thick PIR, thin PUR and the most energy use for the life of the material has thick PUR. Finally, the different results are summarized and show that wood fibre is the material that is most advantageous with the criteria chosen, while the thick variation of PUR is the least advantageous in both environmental aspect and cost.  Discussion: The three methods of analysis that have been used in this work have their advantages and disadvantages. The advantages are that they show concrete answers, and the disadvantages are mainly the programs they are performed on. Input into these programs has been thorough, but as they are slow and difficult to navigate, there may be a risk of errors. The multi-criteria analysis should be reviewed, and more criteria examined is recommended.
76

Transport infrastructure: making more sustainable decisions for noise reduction

Oltean-Dumbrava, Crina, Watts, Gregory R., Miah, Abdul H.S. January 2013 (has links)
There is a global and growing sustainability agenda for surface transport yet there are no specific means of assessing the relative sustainability of infrastructure equipment. Transport noise reduction devices are a significant part of the surface transport infrastructure: they specifically address environmental and social needs, have a high economic impact, and involve a wide range of raw materials raising multiple technical issues. The paper presents an account of the bespoke tool developed for assessing the sustainability of transport noise reduction devices. Regulatory standards for noise reduction devices and the relevant sustainability assessment tools and procedures adopted worldwide were reviewed in order to produce a set of pertinent sustainability criteria and indicators for NRDs projects, which were reviewed and edited during a stakeholder engagement process. A decision making process for assessing the relative sustainability of noise reduction devices was formulated following the review of the literature. Two key stages were identified: (1) collection of data for criteria fulfillment evaluation and (2) multi-criteria analysis for assessing the sustainability of noise reduction devices. Appropriate tools and methods for achieving both objectives are recommended.
77

Multifunktionalitet i skyfallsplaneringen : Utformning av ett ramverk för synliggörande och utvärdering av multifunktionella värden / Multifunctionality in Cloudburst Planning : Developing a Framework for Highlighting and Evaluating Multifunctional Values

Hermansson, Emma, Lindström, Mathilda January 2024 (has links)
Jordens klimat blir allt varmare, och de redan befintliga hoten från kraftiga skyfall förväntas öka. Behovet av att anpassa våra städer till dessa förändringar blir alltmer påtagligt, då det bland annat medför ökade risker för översvämningar, skador på infrastruktur och ekonomiska förluster. En form av klimatanpassningsåtgärder som har fått ökat intresse är multifunktionella skyfallsåtgärder, då de har förmågan att tillgodose fler funktioner och nyttor än enbart vattenhantering. Även multifunktionella skyfallsåtgärder måste dock integreras i stadsmiljön för att vara effektiva och accepteras. Mot bakgrund av det är syftet med studien är att belysa hur ett multifunktionalitetsperspektiv kan integreras i skyfallsplaneringen, med fokus på att belysa platsers funktioner och värden. Specifikt undersöks hur ett kriteriebaserat ramverk kan utformas för att synliggöra och utvärdera sociala, ekonomiska och miljömässiga värden. Studien utforskar också användningen av ramverket för att skapa diskussion och samsyn kring prioriteringar av värden samt identifierar potentiella förbättringar för att bredda ramverkets användbarhet i skyfallsplaneringen.  För att uppnå det här syftet utgår studien från en anpassad version av beslutsstödsmetoden multikriterieanalys, vilket utgör det huvudsakliga ramverket som tas fram och tillämpas i studien. Ramverket tillämpas i de två fallstudierna Botkyrka kommun och Uppsala kommun, där värdena rangordnas utifrån kommunernas prioriteringar. Metoder för datainsamling inkluderar litteraturstudier, workshoppar samt en enkätstudie. Resultaten visar på 20 kriterier som kan integreras i ramverket för att omfatta de centrala aspekterna av multifunktionalitet. Samtidigt betonas att ramverkets utformning bör anpassas efter den specifika kontext där det tillämpas och inte betraktas som statiskt verktyg. Vidare visar resultaten att ramverket har potential att främja diskussioner, gemensam förståelse och kreativt tänkande, samt underlätta kommunikationen mellan olika parter. För att optimera och utvidga ramverkets användbarhet föreslås ytterligare kriterier, inklusive lösningsspecifika, samt ökat deltagande från externa aktörer. Dessutom framhålls behovet av tydligare definitioner och formuleringar av kriterier och frågeställningar för att säkerställa effektiv användning. / The Earth's climate is becoming increasingly warmer, and the already existing threats from cloudbursts and heavy rainfall are expected to increase. The need to adapt our cities to these changes is becoming more urgent, as it brings increased risks of flooding, damage to infrastructure, and economic losses. One form of climate adaptation measure that has gained increased interest is multifunctional stormwater management, as it can provide multiple functions and benefits beyond just water management. However, even multifunctional stormwater measures must be integrated into the urban environment to be effective and accepted. Against this backdrop, this study aims to highlight how a multifunctional perspective can be integrated into cloudburst planning, with a focus on highlighting the functions and values of places. Specifically, it examines how a criteria-based framework can be designed to highlight and evaluate social, economic, and environmental values. The study also explores the use of the framework to create discussion and consensus around value priorities and identifies potential improvements to broaden the framework's usefulness in cloudburst planning.  To achieve this purpose, the study is based on an adapted version of the decision support method multi-criteria analysis, which forms the main framework developed and applied in the study. The framework is applied in the two case studies of Botkyrka Municipality and Uppsala Municipality, where values are ranked based on the municipalities' priorities. Data collection methods include literature studies, workshops, and a survey. The results identify 20 criteria that can be integrated into the framework to encompass the central aspects of multifunctionality. At the same time, it is emphasized that the design of the framework should be adapted to the specific context in which it is applied and not considered a fixed tool. Furthermore, the results show that the framework has the potential to promote discussions, shared understanding, and creative thinking, as well as facilitate communication between different actors. To optimize and expand the framework's usefulness, additional criteria are suggested, including solution-specific ones, as well as increased participation from external actors. Additionally, the need for clearer definitions and formulations of criteria and questions is highlighted to ensure effective use.
78

Utvärdering av multikriterieanalys som verktyg för spatial resursallokering av dagvattenåtgärder för tillskottsvatten i spillvattennät / Evaluation of multi criteria analysis as a tool for spatial resource allocation of stormwater measures for inflow and infiltration to the sewage water system

Vallin, Hanna January 2016 (has links)
Utbyggnation av städer och allt större andel hårdgjorda ytor leder till problem med dagvattenhanteringen. Flödena blir snabbare samtidigt som större mängder än tidigare bildar avrinning och då är det viktigt att de befintliga systemen klarar av att hantera dem. Dagvatten från tak och hårdgjorda ytor och dräneringsvatten från källarfastigheter kan vara kopplat till spillvattennätet och leda till att vattenflödena i ledningarna vid stora regn kan bli betydligt större än de är dimensionerade för, med kapacitetsproblem som följd. En lösning som många VA-huvudmän har implementerat är att använda öppna dagvattenlösningar istället för att välja det mer kostnadskrävande alternativet att bygga ut ledningssystemet. Att koppla om stuprör, brunnar och dräneringsledningar och gräva diken för att leda om vattnet är både kostnads- och resurskrävande. Syftet var därför att undersöka om multikriterieanalys kan fungera som ett lämpligt verktyg för att allokera resurserna till de områden som ger mest nytta per satsad krona. Detta genom att ta fram en metodik för detta syfte och testa dess robusthet för att avgöra om den är lämplig att applicera eller om osäkerheterna i parametervärdena blir för stora för att några slutsatser ska kunna dras. Metodiken som togs fram testades på Bjursås, ett litet samhälle två mil utanför Falun, eftersom omfattande utredningar gjorts i området tidigare, vilket innebar att mycket data fanns att tillgå. Undersökningar gjordes av var mängderna kunde förväntas bli stora, var det fanns stor risk för källaröversvämningar och vilka områden som bidrog mest till bräddningar. Detta utvärderades tillsammans med förväntade åtgärdskostnader och en samlad bedömning gjordes av var nyttan per satsad krona bör bli störst. Stora osäkerheter återfanns i bedömningen. Slutsatsen blev att metoden kan fungera som stöd vid beslutsunderlag, men att den inte är tillräckligt robust för att kunna användas uteslutande utan att efterföljande utvärderingar och kritisk granskning av resultaten måste göras. Detta kan lämpligtvis ske genom en känslighetsanalys. För att resultaten ska utgöra ett användbart verktyg för VA-huvudmannen måste också kostnaderna utvärderas noggrannare än de har gjorts i den här studien. / Urbanization along with a greater amount of hardened surfaces affects the storm water management. When the flows get faster and larger amounts create runoff, it is crucial that the available systems are able to handle the water. Storm water from roofs and asphalt surfaces and drainage water can be connected to the sewage water pipelines and make the flows in the conduits at rainfall much greater than they are designed for, leading to capacity issues. Many municipalities have implemented open storm water solutions instead of choosing the more cost-ineffective way of expanding the conduit system. Reconnecting downspouts, wells and drainage pipelines and digging trenches to lead the water is both cost and resource demanding. Therefore the aim of this study was to investigate whether multi criteria analysis can be used as an appropriate tool in order to allocate the resources to the most beneficial areas. This was done by developing a method for this aim and testing its robustness in order to determine if it is suitable to use in this context or if the uncertainties make the method too unreliable. The robustness in the method developed can be questioned since the uncertainties can be substantial. To be able to use this method, a lot of data is needed and the method needs to be updated relatively often in order to contain relevant information. It is recommended that a sensitivity analysis is performed along with the method, since the use of only one set of parameters can make the result relatively arbitrary. Using a Monte Carlo procedure with the uncertainties defined can reduce the time needed to measure and identify the values. The sensitivity analysis showed that the parameters that have the largest impact on the results are the number of residents living in every real estate with a basement, the catchment areas, the roughness parameters of the pipelines and the use of energy and chemicals in the system. In the future, the urbanization is expected to increase as well as the amount of rainfall and problems related to inflow and infiltration are expected to become more common. The hope is that the method used and its results will be useful for the municipalities’ future planning and to inspire to more studies on this topic.
79

Samordnad varudistribution : Jämförelse mellan två logistikmodeller med nuläget i Sundsvalls Stenstad

Andersson, Petter, Melander, Melander January 2014 (has links)
As the cities are becoming more crowded, the urban distribution has become a major logistical challenge. Some commonproblems in the inner cities arelimited accessibility and idling. Many of Sweden's municipalities are above the limit values for PM10limit set by the EU.Sundsvall is one of these municipalities and has the vision to create a sustainable city and region. Sundsvall LogistikparkAB is part of an EU project, SMARTSET, which is collaborationbetween several cities in Europe. SMARTSETSundsvall is about to develop a market-based sustainable model for city logistics. Itsobjective has been to compare and assess the potential of two business models forcoordinated goods distribution, with a micro terminal, in to Sundsvall Stenstad,with the current status. To achieve the purpose of the survey is the mapping of the current situation made with the help of interviews with shippers and identification of criteria for a multi-criteria analysis. In the result, the interviews compiled and formed the basis of the data used in the MCA. To get the values of the different criteria, the calculations are made and then the dependency between the different criteria illustrated in the scatter plots. It has been found that business model 1 and 2 is better than the current statusofthe majority of the criteria. The study's main purpose has been fulfilled when the MCA has shown that both the business modelsare profitable for shippers and reduces emissions in Sundsvall. The study has also shown that there are more factors than just the profitability and environmental impacts that affect an imple-mentation of any of these business models. To further develop this survey is required that more shippers interviewed and that the stores specifications are compiled. To get a project with a longer lifethan the contribution period required financing method identified. / I och med att städerna blir allt mer befolkade har stadsdistributionen blivit en stor logistisk utmaning. Några vanliga problem i innerstäderna är begränsad framkomlighet och tomgångskörning. Många av Sveriges kommuner ligger överde gränsvärden för PM10som bestämts av EU. Sundsvall är en av dessa kommuner och har som vision att skapa en hållbar stad och region. Sundsvall Logiskpark AB ingår i ett EU-projekt, SMARTSET, som är ett samarbete mellan flera städer i Europa. SMARTSET Sundsvall handlar om att fram en marknadsmässigt hållbar modell för citylogistik. Undersökningens syfte äratt jämförasamt bedöma potentialen hostvå logistikmodellerför samordnad varudistribution,med en mikroterminal,in till Sundsvalls Stenstadmed nuläget.För att uppnå undersökningens syfte har kartläggning av nuläget gjorts med hjälp av interjuver med speditörer samt identifiering av kriterier för en multikriterieanalys. I resultatet har intervjuerna sammanställts och legat till grund för dedata som har använts i multikriterieanalysen. För att få värden på de olika kriterierna har beräkningar gjorts och sedan har beroendet mellan de olika kriterierna illustrerats i scatter plots. Det har visat sig att logistikmodell1 och 2 är bättre än nuläget på majoriteten av kriterierna.Undersökningens huvudsakliga syfte har uppfyllts då multikriterieanalysen harvisat att båda logistikmodellernaär lönsam för speditörerna samt minskar utsläppen i Sundsvall. Undersökningen har också visat att det är fler faktorer än bara lönsamhet och miljöpåverkan som påverkar en implementation av någon av dessa logistikmodeller.För att vidareutveckla denna undersökning krävs det att fler speditörer intervjuas samt att butikernas kravspecifikation sammanställs. För att få ett projekt med längre livslängd än bidragsperioden behövs finansieringssätt identifieras.
80

Multi-criteria analysis in naval ship design

Anil, Kivanc A. 03 1900 (has links)
Approved for public release, distribution is unlimited / Numerous optimization problems involve systems with multiple and often contradictory criteria. Such contradictory criteria have been an issue for marine/naval engineering design studies for many years. This problem becomes more important when one considers novel ship types with very limited or no operational record. A number of approaches have been proposed to overcome these multiple criteria design optimization problems. This Thesis follows the Parameter Space Investigation (PSI) technique to address these problems. The PSI method is implemented with a software package called MOVI (Multi-criteria Optimization and Vector Identification). Two marine/naval engineering design optimization models were investigated using the PSI technique along with the MOVI software. The first example was a bulk carrier design model which was previously studied with other optimization methods. This model, which was selected due to its relatively small dimensionality and the availability of existing studies, was utilized in order to demonstrate and validate the features of the proposed approach. A more realistic example was based on the "MIT Functional Ship Design Synthesis Model" with a greater number of parameters, criteria, and functional constraints. A series of optimization studies conducted for this model demonstrated that the proposed approach can be implemented in a naval ship design environment and can lead to a large design parameter space exploration with minimum computational effort. / Lieutenant Junior Grade, Turkish Navy

Page generated in 0.0621 seconds