Detta examensarbete har utförts som en del av civilingenjörsprogrammet i maskinteknik vid Karlstads Universitet i samarbete med Valmet. För Valmet är försäljning av reservdelar är en vital del av deras totala affär. I avsikt att stärka konkurrenskraften mot kunder i framförallt lågkostnadsländer vill Valmet erbjuda mer kostnadseffektiva lösningar genom att utveckla konstruktionen på befintliga reservdelar. Målet med examensarbetet var därför att ta fram ett systematiskt arbetssätt för produktutveckling av kostnadseffektiva reservdelar och validera det genom implementering på en befintlig produkt i Valmets reservdelssortiment.   Underlaget till det framtagna arbetssättet samlades in genom att utföra en litteraturstudie, en nulägesanalys på Valmet och en intervju på ett företag som är framgångsrikt inom eftermarknad. Arbetssättet syntetiserades som en process med stöttande riktlinjer genom att utgå från Valmets befintliga utvecklingsprocess och integrera teoretiska modeller, principer och verktyg ur vetenskaplig litteratur. Arbetssättet testades sedan på lutmunstycken för sodapannor.   Grunden för det framtagna arbetssättet bestod av en kombination av Value Management och Design to Cost. Fokus i arbetssättet ligger vid att utveckla en reservdel som återställer systemet till sitt normala arbetstillstånd, för ett pris som kunden är beredd att betala, och som balanserar tillförlighet med tillgänglighet så att den totala kostnaden för kunden minimeras.   Genom att implementera det framtagna arbetssättet på lutmunstycken för sodapannor kunde ett förslag på en lösning med 66 % lägre pris och med 50 % lägre total kostnad för kunden tas fram. Implementeringen visade att arbetssättet praktiskt kan användas på enklare reservdelar men att det behöver testas på komplexa produkter av ett tvärfunktionellt team innan det används av Valmet.  Arbetssättet stärker Valmets förutsättningar för att erbjuda ett mer kostnadseffektiv reservdelsortiment.

Palms support the largest leaves in the world and have evolved on Earth for over 120 million years. They are often reported to be the only structure left standing post-hurricane. Cross-sectional shapes of cantilevered structures are important design factors affecting torsional and bending performance. Understanding the shape contribution of natural sections such as palm petioles (modified leaf stalks) is more difficult than those for simple 2D shapes because conventional methods of calculating section properties are not well suited to these irregular shapes. The role of internal structure, material properties and external shape of palm petioles in cantilever performance has been investigated and three main contributions to knowledge result from this research. Firstly, 3D mapping, i.e., the size, orientation and position, of vascular bundles in the Trachycarpus fortunei palm petiole reveals the distributions of stress and Young’s modulus values, providing a more detailed understanding of petioles than previous work. Secondly, bulk elastic material properties along the longitudinal axis of the same petiole are then input to a bi-layered model of the same petiole establishing the Young’s modulus of the two layers without mechanically testing them individually and for determining that the outer layer is not lignified. Thirdly, the largest contribution is the introduction of modified shape transformers employing the use of circular envelopes, eliminating error caused by approximating second moment of area with the torsional constant. This leads to a novel Shape Edge Mapping (SEM) technique which deconstructs petiole cross section shape elements and enables the structural contribution of these elements to be calculated, improving the understanding of the petiole section and how it relates to its mechanical function. This thesis makes a valuable addition to the knowledge of palm function and presents novel techniques for non-destructive extraction of natural shape data for abstraction and use in preliminary engineering design.

In the last two decades, energy is becoming one of the main issues in the manufacturing industry as it contributes substantially to production cost, CO2 emissions, and other destructive environmental impact. Due to rising energy costs, environmental concerns and stringent regulations, manufacturing is increasingly driven towards sustainable manufacturing which needs to address the associated environmental, social and economic aspects simultaneously. One common approach is to achieve sustainability and to implement energy-resource efficient production management systems that enable optimisation of energy consumption and resource utilisation in the production system. However, by reducing energy consumption, the product quality and production cost may be compromised. To remain competitive in the dynamic environment, the energy-efficient management system should not only concern energy consumption but also maintain product quality and production efficiency. This thesis presents a development of the Energy-smart Production Management (e-ProMan) system which provides a systematic, virtual simulation that integrates manufacturing data relating to thermal effect and correlation analysis between energy flow, work flow and data flow for the heating, ventilation and air conditioning (HVAC) system and production process. First, the e-ProMan system comprises of the multidimensional analysis between energy flow, work flow and data flow. The results showed that the product quality is significantly affected by ambient temperature in CNC precision machining. Product quality appears to be improved at lower temperatures. This research highlights the significance of ambient temperature in sustainable precision machining. Second, the simulation experiment was modelled at the production process due to it being the main source of energy consumption in manufacturing. An up-hill workload scenario was found to be the most energy and cost-efficient production processes. In other words, energy consumption, CO2 emission and total manufacturing cost could be reduced when workload capacity and operating machine increase incrementally. Moreover, the e-ProMan system was modelled and simulated using the weather forecast and real-time ambient temperature to reduce energy consumption of the HVAC system. The e-ProMan system results in less energy consumption compared to the fuzzy control system. To conclude, the e-ProMan demonstrates energy efficiency at all relevant levels in the manufacturing: machine, process and plant. For the future research, the e-ProMan system needs to be applied and validated in actual manufacturing environments.

Les textiles techniques enduits sont de plus en plus utilisés pour des applications telles que les structures gonflables, les airbags ou les voiles de parachutes. Ces textiles performants et de faible grammage, sont constitués d’un renfort en tissu polyester thermoplastique (polyéthylène téréphtalate (PET)) ou polyamide (PA) et d’une matrice généralement en PVC. Cependant les contraintes environnementales imposent d’envisager une substitution au PVC, nocif et difficilement recyclable. Les polyuréthanes thermoplastiques représentent des candidats potentiels à cette substitution, mais l’absence d’adhésion inhérente à l’incompatibilité chimique avec le tissu constitue l’un des principaux verrous.Les travaux de cette thèse s’inscrivent dans le cadre du projet INOVANEX ayant pour objectif de réduire l’impact environnemental de textiles enduits types PVC / PET conventionnels par substitution isoperformante d’enduction polyuréthane thermoplastique TPU/ PET suivant une démarche d’éco-conception.Les travaux ont consisté à :1) Améliorer l’adhésion de l’enduction TPU sur le tissu PET via une augmentation de la température d’extrusion. Cette augmentation de la température a été rendue possible grâce à l’ajout de PEBD dans la matrice TPU (avec et sans compatibilisant) pour maintenir une viscosité suffisamment importante pour que le film puisse être extrudé.2) Étudier les propriétés rhéologiques et mécaniques des mélanges TPU/PEBD avec et sans ajout de compatibilisant3) Améliorer l’adhésion du TPU sur le tissu en effectuant des prétraitements du renfort et étudier la tenue en service des matériaux ainsi développés Les recherches menées ont montré une augmentation importante de la force d’adhésion de l’enduction sur le tissu pour les deux méthodes suivies. L’étude de la compatibilisation du mélange TPU/PEBD a montré une forte diminution de la tension interfaciale et une augmentation de la résistance à l’amorçage de la déchirure des mélanges avec ajout du compatibilisant. / Coated technical textiles are widely used for several industrial applications. A lot of producers use the extrusion calendering process to produce coated fabrics because it is one of the cheapest processes. Most of these coated fabrics are made with a polyester fabric and a polyvinyl chloride coating but in order to reduce the environmental impact, the producers are willing to substitute PVC by thermoplastic polyurethane (TPU). However, a technological lock of the calendering of TPU on polyester fabric is the ability to get a good adhesion of the coating on the fabric.This PhD has been realized in collaboration with the different partners of the INOVANEX project which aim is to reduce the environmental impact of PVC coated textiles by the substitution with TPU coated textiles.The main steps of the PhD were:1) Increase the peel strength of the coating on the fabric by increasing the extrusion temperature. It was possible to increase the extrusion temperature thanks to a blend with TPU and LDPE. The LDPE enabled us to maintain the viscosity of the extruded sheet high enough to get a good film2) Study the rheological and mechanical properties of the TPU/LDPE blends with or without compatibilizer3) Increase the peel strength of the TPU on the fabric thanks to several treatments on the fabric before the extrusion of TPU. Study the in-service strength of the materials that have been developed.The results showed a strong adhesion of the coating on the fabric for both studied methods. The study of the compatibilization of the blend has shown an important decrease of the interfacial tension and a strong increase of the resistance to crack ignition with the addition of the compatibilizer.

Made available in DSpace on 2015-02-04T21:38:45Z (GMT). No. of bitstreams: 1 Sheila Ferreira.pdf: 3099826 bytes, checksum: 5067b4517b84c9fb1bdb2e52a003b5e0 (MD5) Previous issue date: 2008-06-03 / Com a evolução dos supermercados brasileiros desde o inicio do Plano Real em 1994, aconteceram muitas transformações nos modelos de operações não apenas com a adoção de recursos tecnológicos e também de formatos, mix de produtos, oferta de serviços, entre outros. Assim o varejo obteve uma forte tendência de concentração, buscando estar próximo ao seu consumidor. Por estar desenvolvendo praticas para melhor se adaptar a este novo cenário essa dissertação dentro dos princípios adotados pelo ECR Efficient Consumer Response, tem como objetivo de pesquisa analisar mais especificamente o processo de gerenciamento por categorias tendo como metodologia um estudo de caso, entre um fabricante da categoria de refrigerados lácteos e um supermercadista com o formato de loja compacta, levando em consideração a parceria e expectativas estabelecidas pelo supermercadista local e a capacitação industria parceira. Os resultados do estudo demonstram que o processo de GC profere resultados positivos na industria e varejo se os mesmos possuírem cultura organizacional alinhada e recursos mínimos necessários.

This work presents optimizations for modern capability machines and specifically for the CHERI architecture, a 64-bit MIPS instruction set extension for security, supporting fine-grained memory protection through hardware-enforced capabilities. The original CHERI model uses 256-bit capabilities to carry information required for various checks helping to enforce memory safety, leading to increased memory bandwidth requirements and cache pressure when using CHERI capabilities in place of conventional 64-bit pointers. In order to mitigate this cost, I present two new 128-bit CHERI capability formats, using different compression techniques, while preserving C-language compatibility lacking in previous pointer compression schemes. I explore the trade-offs introduced by these new formats over the 256-bit format. I produce an implementation in the L3 ISA modeling language, collaborate on the hardware implementation, and provide an evaluation of the mechanism. Another cost related to CHERI capabilities is the memory traffic increase due to capability-validity tags: to provide unforgeable capabilities, CHERI uses a tagged memory that preserves validity tags for every 256-bit memory word in a shadowspace inaccessible to software. The CHERI hardware implementation of this shadowspace uses a capability-validity-tag table in memory and caches it at the end of the cache hierarchy. To efficiently implement such a shadowspace and improve on CHERI’s current approach, I use sparse data structures in a hierarchical tag-cache that filters unnecessary memory accesses. I present an in-depth study of this technique through a Python implementation of the hierarchical tag-cache, and also provide a hardware implementation and evaluation. I find that validity-tag traffic is reduced for all applications and scales with tag use. For legacy applications that do not use tags, there is near zero overhead. Removing these costs through the use of the proposed optimizations makes the CHERI architecture more affordable and appealing for industrial adoption.

Dans cette thèse, nous nous intéressons à l'estimation de modèles conditionnellement hétéroscédastiques (CH) sous différentes hypothèses. Dans une première partie, en modifiant l'hypothèse d'identification usuelle du modèle, nous définissions un estimateur de quasi-maximum de vraisemblance (QMV) non gaussien et nous montrons que, sous certaines conditions, cet estimateur est plus efficace que l'estimateur du quasi maximum de vraisemblance gaussien. Nous étudions dans une deuxième partie l'inférence d'un modèle CH dans le cas où le processus des innovations est distribué selon une loi alpha stable. Nous établissons la consistance et la normalité asymptotique de l'estimateur du maximum de vraisemblance. La loi alpha stable n'apparaissant que comme loi limite, nous étudions ensuite le comportement de ce même estimateur dans le cas où la loi du processus des innovations n'est plus une loi alpha stable mais est dans le domaine d'attraction d'une telle loi. Dans la dernière partie, nous étudions l'estimation d'un modèle GARCH lorsque le processus générateur de données est un modèle CH dont les coefficients sont sujets à des changements de régimes markoviens. Nous montrons que cet estimateur, dans un cadre mal spécifié, converge vers une pseudo vraie valeur et nous établissons sa loi asymptotique. Nous étudions cet estimateur lorsque le processus observé est stationnaire mais nous détaillons également ses propriétés asymptotiques lorsque ce processus est non stationnaire et explosif. Par des simulations, nous étudions les capacités prédictives du modèle GARCH mal spécifié. Nous déterminons ainsi la robustesse de ce modèle et de l'estimateur du QMV à une erreur de spécification de la volatilité. / In this thesis, we focus on the inference of conditionally heteroskedastic models under different assumptions. This thesis consists of three parts and an introductory chapter. In the first part, we use an alternate identification assumption of the model and we define a non Gaussian quasi maximum likelihood estimator. We show that, under certain conditions, this estimator is more efficient than the Gaussian quasi maximum likelihood estimator. In a second part, we study the inference of a conditionally heteroskedastic model when the process of the innovations is distributed as an alpha stable law. We establish the consistency and the asymptotic normality of the maximum likelihood estimator. Since the alpha stable laws appear in general as a limit, we then focus of the behavior of this same estimator when the law of the innovation process is not stable but in the domain of attraction of a stable law. In the last part of this thesis, we study the estimation of a GARCH model when the data generating process is a conditionally heteroskedastic model whose coefficients are subject to Markov switching regimes. We show that, in a missspecified framework, this estimator converges toward a pseudo true value and we establish its asymptotic properties when this process is non stationary and explosive. Through simulations, we investigate the predictive ability of the missspecified GARCH model. Thus we determinate the robustness of the model and of the estimator of the quasi maximum likelihood to the missspecification of the volatility

Orientador: Luzia Aparecida Trinca / Resumo: Nas mais diversas áreas do conhecimento se procura aumentar a eficiência dos delineamentos experimentais, principalmente, para minimizar os custos das pesquisas. O uso dos delineamentos ótimos, com seus diferentes critérios de otimização, é fundamental para se obter resultados que maximizam a informação em estudos experimentais. A maioria dos métodos pressupõe homogeneidade de variâncias, a qual nem sempre é veri cada no conjunto de dados. O objetivo deste trabalho é desenvolver uma metodologia para construção de delineamentos ótimos exatos e cientes em situações de variância não homogênea. Assume-se que linearidade e homoscedasticidade são obtidas via o uso de transformações da família Box-Cox e, além de critérios de otimização puros, critérios compostos que combinam duas propriedades são propostos. Resultados para vários exemplos sob os modelos de primeira e segunda ordem são obtidos e discutidos. / Abstract: In several areas of knowledge we seek to increase the efficiency of experimental designs, mainly in order to minimize the costs of reaserch. The use of optimal design with different optimization criteria is fundamental to obtain results that maximize the information in experimental studies. Most of the methods assume homogeneity of variances, which is not always verified in the data set. The goal of this work is to develop a methodology to construct exact optimal or efficient designs in situations of nonhomogeneous variance. It is assumed that application of a transformation from the Box-Cox family accomplish both linearity and homocedasticity. Pure design criterion as well as compound criteria using two desired properties are used. Results for several examples assuming first and second order models are presented and discussed. / Doutor

The performance of many protocols and applications of Vehicular Ad hoc Networks (VANETs), depends on vehicles obtaining enough fresh information on the status of their neighbouring vehicles. This should be fulfilled by exchanging Basic Safety Messages (BSMs) also called beacons using a shared channel. In dense vehicular conditions, many of the beacons are lost due to channel congestion. Therefore, in such conditions, it is necessary to control channel load at a level that maximizes BSM dissemination. To address the problem, in this thesis algorithms for adaptation of beaconing to control channel load are proposed. First, a position-based routing protocol for VANETs is proposed and the requirement of adaptive beaconing to increase the performance of the protocol is indicated. The routing protocol is traffic-aware and suitable for city environments and obtains real-time traffic information in a completely ad hoc manner without any central or dedicated control, such as traffic sensors, roadside units, or information obtained from outside the network. The protocol uses an ant-based algorithm to find a route that has optimum network connectivity. Using information included in small control packets called ants, vehicles calculate a weight for every street segment that is proportional to the network connectivity of that segment. Ant packets are launched by vehicles in junction areas. To find the optimal route between a source and destination, a source vehicle determines the path on a street map with the minimum total weight for the complete route. The correct functionality of the protocol design has been verified and its performance has been evaluated in a simulation environment. Moreover, the performance of the protocol in different vehicular densities has been studied and indicated that in dense vehicular conditions the performance of the protocol degrades due to channel load created by uncontrolled periodic beaconing. Then, the problem of beaconing congestion control has been formulated as non-cooperative games, and algorithms for finding the equilibrium point of the games have been presented. Vehicles as players of the games adjust their beacon rate or power or both, based on the proposed algorithms so that channel load is controlled at a desired level. The algorithms are overhead free and fairness in rate or power or both rate and power allocation are achieved without exchanging excess information in beacons. Every vehicle just needs local information on channel load while good fairness is achieved globally. In addition, the protocols have per-vehicle parameters, which makes them capable of meeting application requirements. Every vehicle can control its share of bandwidth individually based on its dynamics or requirements, while the whole usage of the bandwidth is controlled at an acceptable level. The algorithms are stable, computationally inexpensive and converge in a short time, which makes them suitable for the dynamic environment of VANETs. The correct functionality of the algorithms has been validated in several high density scenarios using simulations.

Optical fibre has become the dominant theme of transmission in long haul, high data rate communication systems due to its tremendous bandwidth and low loss. Radio over Fibre (RoF) technology facilitates the seamless integration between wireless and optical communication systems and found to be the most promising solution to meet the exponential bandwidth demands expected for the upcoming years. However, the main bit-rate/distance limitation in RoF systems is the chromatic dispersion. In this thesis, the two generations of RoF technologies, namely Analogue RoF (ARoF) and Digital RoF (DRoF) are investigated. The overall aim of this research is to optimise the optical bandwidth utilisation of these two approaches for a typical transmission of the fronthaul link proposed in the next generation Centralised Radio Access Network (C-RAN). Consequently, a number of physical layer design scenarios for the optimised transmission of the Radio Frequency (RF) signals over a Standards Single Mode Fibre (SSMF) are demonstrated. Firstly, for an ARoF transmission, where the analogue RF signals are transported over SSMF using an optical carrier, a bidirectional link transmitting four Downlink/Uplink channels in a chromatic dispersion limited scenario is designed. Simulation results have shown a clear constellation diagram of a 2.5 Gb/s RF signal transmission over 120 km fibre length. Secondly, a DRoF system with reduced optical bandwidth occupancy is proposed. This system employs an optical Duobinary transmission to the digitised RF signal at the transmitter side to reduce its spectrum and to address the chromatic dispersion effect, simultaneously. Simulation results demonstrate the capability of the proposed system to maintain high-quality transmission of the digitised signals over 70 km of fibre distance without dispersion compensation requirements. Finally, an advanced DRoF transmission link based on integrating digital Optical Single Sideband (OSSB) transmission with Duobinary encoding scheme is designed. Simulation results have clearly verified system's robustness against transmission impairments and have better performances in terms of the obtained BER and EVM with respect to the 3GPP standardised values. Moreover, the results show that both transmission distance and power budget are furtherly improved in comparison with two other digital transmission scenarios.