1 |
A Monte-Carlo approach to tool selection for sheet metal punching and nibblingSummad, Emad January 2001 (has links)
Selecting the best set of tools to produce certain geometrical shapes/features in sheet metal punching is one of the problems that has a great effect on product development time, cost and achieved quality. The trend nowadays is, where at all possible, to limit design to the use of standard tools. Such an option makes the problem of selecting the appropriate set of tools even more complex, especially when considering that sheet metal features can have a wide range of complex shapes. Another dimension of complexity is limited tool rack capacity. Thus, an inappropriate tool selection strategy will lead to punching inefficiency and may require frequent stopping of the machine and replacing the required tools, which is a rather expensive and time consuming exercise. This work demonstrates that the problem of selecting the best set of tools is actually a process of searching an explosive decision tree. The difficulty in searching such types of decision trees is that intermediate decisions do not necessarily reflect the total cost implication of carrying out such a decision. A new approach to solve such a complex optimisation problem using the Monte Carlo Simulation Methods has been introduced in this thesis. The aim of the present work was to establish the use of Monte Carlo methods as an "assumptions or rule free" baseline or benchmark for the assessment of search strategies. A number of case studies are given, where the feasibility of Monte Carlo Simulation Methods as an efficient and viable method to optimise such a complex optimisation problem is demonstrated. The use of a Monte Carlo approach for selecting the best set of punching tools, showed an interesting point, that is, the effect of dominant "one-to-one" feature/tool matches on the efficiency of the search. This naturally led on to the need of a search methodology that will be more efficient than the application of the Monte Carlo method alone. This thesis presents some interesting speculations for a hybrid approach to tool selection to achieve a better solution than the use of the Monte Carlo method alone to achieve the optimum solution in a shorter time.
|
2 |
Development of an integrated building design information interfacePunjabi, Sonia Arjun 29 August 2005 (has links)
This research recognizes the need for building simulation/performance tools that
can easily be integrated into the building design process. The study examines available
simulation tools and attempts to determine why these tools are not used by building
designers/architects. Findings confirm that the complexity of simulation tools created by
scientists, who are more technically oriented, discourages use by architects who are
more visually oriented people.
The evaluation and analysis of available simulation tools suggests a thorough
research methodology for creating a new front-end interface that solves current usage
problems. The research is limited to the interface design of the new front-end which is
named Integrated Building Design Information Interface (IBDII). The new front end
provides an interface that allows designers to make more informed decisions during the
design process while providing a front-end that supports AutoCAD and permits a user
interface where the mode of input is graphical and not numerical.
Criteria for the new front-end interface enable the development of a series of
mock-up interface designs that are responsive to the needs of architects. A working
graphical user interface of the building information prototype is created and is then put
through an empirical user testing. The usability testing establishs the usefulness,
effectiveness, likeability and learnability of the developed interface design. The testing
includes six factors which act as indicators of usability and provide suggestions for
future developments. The testing evaluation ascertains that the interface is easy to learn
and use. Findings also show that the best feature of integrated building design
information front-end is its interface design and there is room for improvement in the
way input is selected.
|
3 |
Simulation Methods at Epiroc within Underground Rock Excavation : Simuleringsmetoder vid Epiroc inom underjordsdivisionen.Granberg, Simon January 2022 (has links)
Epiroc Underground Rock Excavation is a manufacturer of machines that operate in underground mines. The machines are complex and advanced with different functions and systems that interact with each other. Simulations provides a picture of machine design, its functions and how the real-world result would be. This method enables an iterative way of working with several different design solutions. Simulations is a crucial method for reducing cost and time-to-market. Recently, Epiroc has taken initiatives regarding development and continuous improvements within the underground division. Lack of documentation regarding what simulation methods that is used, and its purposes makes it difficult to work with development and improvements. The long-term target for Epiroc is to move the physical verification of machine systems, functions, and components to a digital environment. The mission of this project has been to collect and identify simulation methods used within the division and collect key information for future work. The information has been collected through interviews with simulation experts and the identified information is presented to get an understanding about the current state. Furthermore, waste and improvement areas has been highlighted within this thesis. / Epirocs underjordsdivision tillverkar maskiner som används inom underjordsarbete. Maskinerina är komplexa och avancerade med många olika funktioner och system som skall interagera med varandra. Simuleringar ger en första anblick i hur designen och maskiners funktioner senare kommer att fungera i verkligheten. Simuleringar möjliggör ett itterativt arbetssätt med flera olika designlösningar för att komma fram till den bästa lösningen. Detta är avgörande för att hålla ner kostnaden och att minska tiden-till-marknaden. På senare tid har initiativ tagits för att jobba med bland annat utveckling och ständiga förbättringar inom underjordsdivisionen. Bristande dokumentation gällande vilka simuleringsmetoder som används och syftet med dem gör det svårt att bedriva utvecklingsarbete gällande nya produkter. Det långsiktiga målet för Epiroc är att maskinens delar, system och funktioner skall kunna verifieras i en virtuell miljö istället för på fysisk maskin. Målet för det här projektet har varit att samla och identifiera simuleringsmetoder som används inom divisionen idag, för att förbereda för framtida arbete. Detta har gjorts genom att utföra intervjuer med simuleringsexperter och genom en nulägesanalys. Vidare så har även slöserier och förbättringsområden identifierats.
|
4 |
A Framework for the Implementation of Lighting Design and Light Cognitive Tools in Kuwait's Design PedagogyAli, Shahd Mahmoud 12 April 2022 (has links)
Lighting is an important design element that affects human health, comfort levels, mood, feelings, and the overall experience in spaces. Academically, light is integrated late in design education. Architecture and interior design schools usually introduce it as a design principle during the second or third year of education. As a result, students perceive it as an additive element in the schematic or design development phases rather than a concept generator from the ideation phase. If we accept that lighting design is essential in the conceptual design phase in order to create better-performing light spaces, then a new lighting design integration is needed in design curricula to encourage students to think about it from the ideation phase, enhance their understanding of lighting design knowledge, and facilitate their cognitive thinking and decision-making processes to eventually produce better performing lighting design projects.
The purpose of this research was to develop a new pedagogical framework for the integration of lighting design knowledge and lighting cognitive tools in design pedagogy to invite students to use it as a concept generator from the early design stages and to aid their cognitive thinking to produce high-quality lighting environments. The framework presents a learning path to introduce lighting design in a sequence from the first year of design education according to three main knowledge domains: the tacit, the procedural, and the explicit. The research contributes to shifting the current approach to lighting design education in Kuwait as an example and in architecture and interior design schools in general.
The researcher used multiple sources of data to develop the framework. First, she reviewed scholarly work and the literature that address lighting design pedagogy, design pedagogical theories, design curricula development models, the lighting design process, and design cognitive tools to create a logical argument for the framework's theoretical structure and to develop its research methods. Second, she analyzed lighting design documents from the United States' developed lighting design programs and Kuwait University to understand the current lighting design pedagogical structure, teaching methods, cognitive design tools, and foundational lighting knowledge. Third, she interviewed current lighting design educators from Kuwait University to understand the current lighting pedagogical model and sequence. Fourth, she interviewed lighting design educators from the United States to obtain new foundational lighting knowledge, creative teaching methods, advanced design cognitive tools, and other suggestions to improve lighting design pedagogy. Fifth, the researcher transferred knowledge from the United States' developed programs to Kuwait University to develop the new framework. Lastly, she presented the preliminary framework to lighting design professionals and educators using a Delphi Method to enhance it further and to rate its implementation possibilities. / Doctor of Philosophy / Lighting is an important design element that affects human health, comfort levels, mood, feelings, and the overall experience in spaces. Academically, light is integrated late in design education. Architecture and interior design schools usually introduce it as a design principle during the second or third year of education. As a result, students perceive it as an additive element in the schematic or design development phases rather than a concept generator from the ideation phase. If we accept that lighting design is essential in the conceptual design phase in order to create better-performing light spaces, then a new lighting design integration is needed in design curricula to encourage students to think about it from the ideation phase, enhance their understanding of lighting design knowledge, and facilitate their cognitive thinking and decision-making processes to eventually produce better performing lighting design projects.
The purpose of this research was to develop a new pedagogical framework for the integration of lighting design knowledge and lighting cognitive tools in design pedagogy to invite students to use it as a concept generator from the early design stages and to aid their cognitive thinking to produce high-quality lighting environments. The framework presents a learning path to introduce lighting design in a sequence from the first year of design education according to three main knowledge domains: the tacit, the procedural, and the explicit. The research contributes to shifting the current approach to lighting design education in Kuwait as an example and in architecture and interior design schools in general.
The researcher used multiple sources of data to develop the framework. First, she reviewed scholarly work and the literature that address lighting design pedagogy, design pedagogical theories, design curricula development models, the lighting design process, and design cognitive tools to create a logical argument for the framework's theoretical structure and to develop its research methods. Second, she analyzed lighting design documents from the United States' developed lighting design programs and Kuwait University to understand the current lighting design pedagogical structure, teaching methods, cognitive design tools, and foundational lighting knowledge. Third, she interviewed current lighting design educators from Kuwait University to understand the current lighting pedagogical model and sequence. Fourth, she interviewed lighting design educators from the United States to obtain new foundational lighting knowledge, creative teaching methods, advanced design cognitive tools, and other suggestions to improve lighting design pedagogy. Fifth, the researcher transferred knowledge from the United States' developed programs to Kuwait University to develop the new framework. Lastly, she presented the preliminary framework to lighting design professionals and educators using a Delphi Method to enhance it further and to rate its implementation possibilities.
|
5 |
Mobility prediction and Multicasting in Wireless Networks: Performance and AnalysisVenkatachalaiah, Suresh, suresh@catt.rmit.edu.au January 2006 (has links)
Handoff is a call handling mechanism that is invoked when a mobile node moves from one cell to another. Such movement may lead to degradation in performance for wireless networks as a result of packet losses. A promising technique proposed in this thesis is to apply multicasting techniques aided by mobility prediction in order to improve handoff performance. In this thesis, we present a method that uses a Grey model for mobility prediction and a fuzzy logic controller that has been fine-tuned using evolutionary algorithms in order to improve prediction accuracy. We also compare the self-tuning algorithm with two evolutionary algorithms in terms of accuracy and their convergence times. Our proposed method takes into account signal strengths from the base stations and predicts the signal strength of the next candidate base station in order to provide improved handover performance. The primary decision for mobility prediction is the accurate prediction of signal strengths obtained from the base stations and remove any unwanted errors in the prediction using suitable optimisation techniques. Furthermore, the model includes the procedures of fine-tuning the predicted data using fuzzy parameters. We also propose suitable multicasting algorithms to minimise the reservation of overall network resource requirements during handoff with the mobility prediction information. To be able to efficiently solve the problem, the situation is modelled using a multicast tree that is defined to maintain connectivity with the mobile node, whilst ensuring bandwidth guarantees and a minimum hop-count. In this approach, we have tried to solve the problem by balancing two objectives through putting a weight on each of two costs. We provide a detailed description of an algorithm to implement join and prune mechanisms, which will help to build an optimal multicast tree with QoS requirements during handoff as well as incorporating dynamic changes in the positions of mobile nodes. An analysis of how mobility prediction helps in the selection of potential Access Routers (AR) with QoS requirements - which affects the multicast group size and bandwidth cost of the multicast tree -- is presented. The proposed technique tries to minimise the number of multicast tree join and prune operations. Our results show that the expected size of the multicast group increases linearly with an increase in the number of selected destination AR's for multicast during handoff. We observe that the expected number of joins and prunes from the multicast tree increases with group size. A special simulation model was developed to demonstrate both homogeneous and heterogeneous handoff which is an emerging requirement for fourth generation mobile networks. The model incorporates our mobility prediction model for heterogeneous handoff between the Wireless LAN and a cellular network. The results presented in this thesis for mobility prediction, multicasting techniques and heterogeneous handoff include proposed algorithms and models which aid in the understanding, analysing and reducing of overheads during handoff.
|
6 |
Direction Finding Performance Of Antenna Arrays On Complex Platforms Using Numerical Electromagnetic Simulation ToolsOzec, Mustafa Onur 01 September 2011 (has links) (PDF)
An important step for the design of direction finding systems is the performance evaluation
using numeric electromagnetic simulation tools. In this thesis, a method is presented for both
modeling and simulation in a numeric electromagnetic simulation tool FEKO. The method
relies on the data generated by FEKO. The data is then processed by correlative interferometer
algorithm. This process is implemented in a MATLAB environment. Different types of
antenna arrays including dipole, monopole and discone antennas are used. The antenna arrays
are mounted on a UAV and SUV in order to see the platform effects. The direction finding
performance is evaluated for different scenarios. It is shown that the presented approach is an
effective tool for understanding the direction finding characteristic of antenna arrays.
|
7 |
Multi-Resolution Modeling of Managed Lanes with Consideration of Autonomous/Connected VehiclesFakharian Qom, Somaye 29 June 2016 (has links)
Advanced modeling tools and methods are essential components for the analyses of congested conditions and advanced Intelligent Transportation Systems (ITS) strategies such as Managed Lanes (ML). A number of tools with different analysis resolution levels have been used to assess these strategies. These tools can be classified as sketch planning, macroscopic simulation, mesoscopic simulation, microscopic simulation, static traffic assignment, and dynamic traffic assignment tools. Due to the complexity of the managed lane modeling process, this dissertation investigated a Multi-Resolution Modeling (MRM) approach that combines a number of these tools for more efficient and accurate assessment of ML deployments.
This study clearly demonstrated the differences in the accuracy of the results produced by the traffic flow models incorporated into different tools when compared with real-world measurements. This difference in the accuracy highlighted the importance of the selection of the appropriate analysis levels and tools that can better estimate ML and General Purpose Lanes (GPL) performance. The results also showed the importance of calibrating traffic flow model parameters, demand matrices, and assignment parameters based on real-world measurements to ensure accurate forecasts of real-world traffic conditions. In addition, the results indicated that the real-world utilization of ML by travelers can be best predicated with the use of dynamic traffic assignment modeling that incorporates travel time, toll, and travel time reliability of alternative paths in the assignment objective function. The replication of the specific dynamic pricing algorithm used in the real-world in the modeling process was also found to provide the better forecast of ML utilization.
With regards to Connected Vehicle (CV) operations on ML, this study demonstrated the benefits of using results from tools with different modeling resolution to support each other’s analyses. In general, the results showed that providing toll incentives for Cooperative Adaptive Cruise Control (CACC)-equipped vehicles to use ML is not beneficial at lower market penetrations of CACC due to the small increase in capacity with these market penetrations. However, such incentives were found to be beneficial at higher market penetrations, particularly with higher demand levels.
|
8 |
Stratégie de navigation sûre dans un environnement industriel partiellement connu en présence d’activité humaine / Safe navigation strategy in a partially known industrial environment in the presence of human activityBurtin, Gabriel Louis 26 June 2019 (has links)
Dans ces travaux, nous proposons un système sûr pour la localisation de robot mobile en milieu intérieur structuré. Le principe repose sur l’utilisation de deux capteurs (lidar et caméra monoculaire) combinés astucieusement pour assurer une rapidité de calcul et une robustesse d’utilisation. En choisissant des capteurs reposant sur des principes physiques différents, les chances qu'ils se retrouvent simultanément perturbés sont minimes. L’algorithme de localisation doit être rapide et efficient tout en conservant la possibilité de fournir un mode dégradé dans éventualité où l’un des capteurs serait endommagé. Pour atteindre cet objectif de localisation rapide, nous optimisons le traitement des données à divers niveaux tels que la quantité de données à traiter ou l’optimisation algorithmique. Nous opérons une approximation polygonale des données du lidar 2D ainsi qu’une détection des segments verticaux dans l’image couleur. Le croisement de ces deux informations, à l’aide d’un filtre de Kalman étendu, nous donne alors une localisation fiable. En cas de perte du lidar, le filtre de Kalman peut toujours fonctionner et, en cas de perte de la caméra, le robot peut faire un recalage laser avec le lidar. Les données des deux capteurs peuvent également servir à d’autres objectifs. Les données lidar permettent d’identifier les portes (points de collision potentiels avec des humains), les données caméra peuvent permettre la détection et le suivi des piétons. Les travaux ont été majoritairement menés et validés avec un simulateur robotique avancé (4DV-Sim) puis ont été confirmés par des expériences réelles. Cette méthodologie permet à la fois de développer nos travaux et de valider et améliorer le caractère fonctionnel de cet outil de robotique. / In this work, we propose a safe system for robot navigation in an indoor and structured environment. The main idea is the use of two combined sensors (lidar and monocular camera) to ensure fast computation and robustness. The choice of these sensors is based on the physic principles behind their measures. They are less likely to go blind with the same disturbance. The localization algorithm is fast and efficient while keeping in mind the possibility of a downgraded mode in case of the failure of one sensor. To reach this objective, we optimized the data processing at different levels. We applied a polygonal approximation to the 2D lidar data and a vertical contour detection to the colour image. The fusion of these data in an extended Kalman filter provides a reliable localization system. In case of a lidar failure, the Kalman filter still works, in case of a camera failure the robot can rely upon a lidar scan matching. Data provided by these sensors can also deserve other purposes. The lidar provides us the localization of doors, potential location for encounter with humans. The camera can help to detect and track humans. This work has been done and validated using an advanced robotic simulator (4DV-Sim), then confirmed with real experiments. This methodology allowed us to both develop our ideas and confirm the usefulness of this robotic tool.
|
9 |
Grafický editor simulačních modelů / Graphical Editor of Simulation ModelsBulka, Pavol January 2011 (has links)
This thesis deals with development of a graphical editor of simulation models. Design of the editor is based on a research which was carried out among professional simulation systems with graphical user interface. The new graphical editor is based on DEVS formalism since it is quite hard to implement a reliable simulation tool. This formalism was verified in great number of its implementation. One of them is Adevs library which is used in editor. Plugins can be used to provide additional features (i.e. another simulator) without need for changing the code of the editor. Another way to extend editor functionality are user scripts. The thesis presents the software development process of the editor in detail. Furthermore, a brief summary of DEVS formalism along with some DEVS modifications and extensions is included. In the end, a set of tests which were used for editor testing on multiple platforms is added.
|
10 |
Energy Efficiency Assessment,based on Field Measurements andComputational Simulations : A Swedish Hypermarket’s case studyCorceiro, Beatriz January 2022 (has links)
This study aims to compare the energy consumption of a supermarket according to field measurements and results from building’s simulation software. Additionally, measures of energy efficiency to minimize the energy intensity of the supermarket are investigated. For such purpose, an ICA MAXI hypermarket in Bålsta, Stockholm, with a total conditioned area of 6570 m2 has being under analysis. This hypermarket operates with a trans-critical CO2 booster refrigeration system, which allows to recover the heat taken out from the refrigeration cabinets to warm up the sales area, when necessary and the only energy source it uses is electricity. Ground source energy storage is used to store part of this heat and enable an effective space heating and domestic hot water supplies. This system is also responsible to provide the required space cooling. In that sense, the referred hypermarket is using the state of the art refrigeration system for supermarkets in cold climate’s countries. Results from the field measurements performed in 2021 showed a total electricity consumptionof 1734 MWh, which corresponds to 264 kWh/m2. This value is in accordance with several studies’ conclusions. However, the values predicted by the simulation tools appointed a lower annual consumption. EnergyPlus and CyberMart software were used to simulate the power loads of ICA MAXI. Subsequently, a Python tool was used to compute the energy consumption by the refrigeration system, taking into account the demands found on the building’s simulation tools. In the end, EnergyPlus’ model predicted an annual energy consumption of 1347 MWh, which equals 205 kWh/m2. Out of the 387 MWh gap, 266 MWh are due to the assumptions taken for the energy consumed by the electrical appliances, 120 MWh resulted from the non-optimal control strategy used on the refrigerationsystem and the remaining 48 MWh were related to different outsides temperatures, predicted on the model and field measurements. This allows to conclude that by managing the current refrigerationsystem in an optimal way, 77.6 thousands of swedish kroner may be saved and the equivalent of about 11 tons of CO2 can be avoided annually. The final results from CyberMart tool were close to the EnergyPlus’ ones and this software was found to be much more user-friendly. In addition, with the aim to identify energy efficiency measures to be applied in this hypermarket, several scenarios were constructed in EnergyPlus, by changing the temperature setpoints of the system, the infiltration rate and the store’s location. Findings pointed out that adapting the indoor temperature for Summer and Winter months can lead to energy savings. / Denna studie syftar till att jämföra energiförbrukningen i en stormarknad enligt fältmätningar och resultat från byggnadens simuleringsprogram. Dessutom undersöks mått på energieffektivitet för att minimera energiintensiteten i stormarknaden. För detta ändamål har en ICA MAXI stormarknad i Bålsta, Stockholm, med en total konditionerad yta på 6570 m2 under analys. Denna stormarknad arbetar med ett trans-kritiskt CO2 booster-kylsystem, som gör det möjligt att återvinna värmen som tas ut från kylskåpen för att värma upp försäljningsområdet, när det behövs och den enda energikälla den använder är elektricitet. Lagring av markenergi används för att lagra en del av denna värme och möjliggöra en effektiv uppvärmning av utrymmen och varmvattenförsörjning. Detta system är också ansvarigt för att tillhandahålla den nödvändiga utrymmeskylningen. I den meningen använder den hänvisade stormarknaden det toppmoderna kylsystemet för stormarknader i länder med kalla klimat. Resultat från de fältmätningar som utfördes 2021 visade en total elförbrukning på 1734 MWh, vilket motsvarar 264 kWh /m2. Detta värde överensstämmer med flera studiers slutsatser. Men de värden som förutspåddes av simuleringsverktygen utsåg en lägre årlig förbrukning. Programvaran EnergyPlus och CyberMart användes för att simulera strömbelastningarna för ICA MAXI. Därefter användes ett Python-verktyg för att beräkna energiförbrukningen i kylsystemet, med hänsyn tagen till de krav som finns på byggnadens simuleringsverktyg. Till slut förutspådde EnergyPlus modell en årlig energiförbrukning på 1347 MWh, vilket motsvarar 205 kWh /m2.Av gapet på 387 MWh beror 266 MWh på de antaganden som gjorts för den energi som förbrukas av de elektriska apparaterna, 120 MWh härrörde från den icke-optimala styrstrategin som användes på kylsystemet och de återstående 48 MWh var relaterade till olika utomhustemperaturer, förutspått på modellen och fältmätningar. Detta gör det möjligt att dra slutsatsen att genom att hantera nuvarande kylsystem på ett optimalt sätt kan 77,6 tusen svenska kronor sparas och motsvarande cirka 11 ton CO2 kan undvikas årligen. De slutliga resultaten från CyberMart- verktyget låg nära EnergyPlus och denna programvara visade sig vara mycket mer användarvänlig. Dessutom, i syfte att identifiera energieffektivitetsåtgärder som ska tillämpas i denna stormarknad, konstruerades flera scenarier i EnergyPlus, genom att ändra systemets temperaturbörvärden, infiltrationshastigheten och butikens läge. Resultaten påpekade att anpassning av inomhustemperaturen för sommar- och vintermånaderna kan leda till energibesparingar.
|
Page generated in 0.1484 seconds