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  • 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.
1

Large-signal characterization and modeling of nonlinear devices using scattering parameters

Call, John B. 07 November 2002 (has links)
Characterization and modeling of devices at high drive levels often requires specialized equipment and measurement techniques. Many large-signal devices will never have traditional nonlinear models because model development is expensive and time-consuming. Due to the complexity of the device or the size of the application market, nonlinear modeling efforts may not be cost effective. Scattering parameters, widely used for small-signal passive and active device characterization, have received only cursory consideration for large-signal nonlinear device characterization due to technical and theoretical issues. We review the theory of S-parameters, active device characterization, and previous efforts to use S-parameters with large-signal nonlinear devices. A robust, calibrated vector-measurement system is used to obtain device scattering parameters as a function of drive level. The unique measurement system architecture allows meaningful scattering parameter measurements of large-signal nonlinear devices, overcoming limitations reported by previous researchers. A three-port S-parameter device model, with a nonlinear reflection coefficient terminating the third port, can be extracted from scattering parameters measured as a function of drive level. This three-port model provides excellent agreement with device measurements across a wide range of drive conditions. The model is used to simulate load-pull data for various drive levels which are compared to measured data. / Master of Science
2

Tack för kaffet! : - en analys av konsumentbeteende hos Premium Coffees potentiella kunder

Holmberg, Niclas, Frank, Richard January 2010 (has links)
<p>Hur resonerar potentiella kunder kring inköp av produkten som ens företag tillhandahåller? En av de främsta frågorna hos en marknadsförare, men också en fråga som är aktuell i vår marknadsekonomi i stort. Konsumentbeteende är därför ett givet fält inom företagsekonomin. Men hur går det till när konsumenten är ett företag? Vilka aspekter är viktiga och varför? Vilka marknadsföringsinsatser bör genomföras utifrån denna adderade förståelse? Det är utgångspunkten för denna uppsats. För att kunna svara på dessa frågor har en ny konsumentbeteendemodell utarbetats, vilket skett utifrån befintliga teorier inom konsumentbeteende och då särskilt den så kallade svarta lådan-modellen. Målet med modellen är att kasta ljus över relevanta aspekter och processer som beaktas och gås igenom i samband med inköp inom ett företag.</p><p>Studien avser inköp av kaffemaskiner avgränsat till potentiella kunder för kaffe- och kaffemaskinleverantören Premium Coffee och dess produkt Nespresso, med betoning på större företag i Stockholmsområdet. Informationsinsamlingen har skett med hjälp av enkäter per mail.</p><p>Utifrån vår empiri och analys av denna har vi gjort antagandet att priset är den absolut mest styrande faktorn för gruppen. Det verkar dock som om man kan tänka sig att betala mer om detta ”mer” är konkret och efterfrågat. Hit verkar inte en godare smak och möjligheter till varumärkesbyggande finnas utan snarare värden som miljövänlighet, kvalité och hållbarhet. Vidare kan vi också anta att inköp nästan alltid sker via anbud.</p><p>Utifrån detta kan man dra slutsatser kring vilka insatser som skulle kunna genomföras. Hit hör att berättiga sitt ändå högre pris, men också utforma ett bättre svar på miljöfrågorna och en uppväxling av positioneringsaktiviteterna.</p> / <p>How do potential customers reason concerning the purchase of a product supplied? This is one of the main issues for a marketer, but also an issue that is current in our market economy at large. Consumer behaviour is a given field of business economy. But how does this work when the consumer is a company? What marketing efforts should be implemented based on these new findings? This is the starting point of this essay. To answer these questions, a new consumer model, has therefore, been developed, which is based on existing theories of consumer behaviour and in particular the so-called black box model. The goal of the model is to shed light on the relevant aspects and processes that are reviewed and considered in connection to the purchase of an enterprise.</p><p>The study relates to the purchase of coffee machines to the limited prospects for the coffee and coffee machine supplier Coffee Premium, with an emphasis on large companies in the Stockholm region. Information has been collected using questionnaires by mail.</p><p>Based on our empirical data, we can assume that price is the absolutely most governing factor for the group. They are however willing to pay for more if this "more" is defined and demanded. It does not seem as a better taste and the ability to strengthen the brand are aspects considered as such but rather aspects as quality and durability. Furthermore, we can also assume that the purchase is almost always done through tenders.</p><p>Based on this we are able to draw a number of conclusions about what actions that could be implemented. These include, for example, to review the pricing, combined with the aim to justify the higher prices, but also design a better response to environmental issues and an up shift of positioning activities.</p>
3

Tack för kaffet! : - en analys av konsumentbeteende hos Premium Coffees potentiella kunder

Holmberg, Niclas, Frank, Richard January 2010 (has links)
Hur resonerar potentiella kunder kring inköp av produkten som ens företag tillhandahåller? En av de främsta frågorna hos en marknadsförare, men också en fråga som är aktuell i vår marknadsekonomi i stort. Konsumentbeteende är därför ett givet fält inom företagsekonomin. Men hur går det till när konsumenten är ett företag? Vilka aspekter är viktiga och varför? Vilka marknadsföringsinsatser bör genomföras utifrån denna adderade förståelse? Det är utgångspunkten för denna uppsats. För att kunna svara på dessa frågor har en ny konsumentbeteendemodell utarbetats, vilket skett utifrån befintliga teorier inom konsumentbeteende och då särskilt den så kallade svarta lådan-modellen. Målet med modellen är att kasta ljus över relevanta aspekter och processer som beaktas och gås igenom i samband med inköp inom ett företag. Studien avser inköp av kaffemaskiner avgränsat till potentiella kunder för kaffe- och kaffemaskinleverantören Premium Coffee och dess produkt Nespresso, med betoning på större företag i Stockholmsområdet. Informationsinsamlingen har skett med hjälp av enkäter per mail. Utifrån vår empiri och analys av denna har vi gjort antagandet att priset är den absolut mest styrande faktorn för gruppen. Det verkar dock som om man kan tänka sig att betala mer om detta ”mer” är konkret och efterfrågat. Hit verkar inte en godare smak och möjligheter till varumärkesbyggande finnas utan snarare värden som miljövänlighet, kvalité och hållbarhet. Vidare kan vi också anta att inköp nästan alltid sker via anbud. Utifrån detta kan man dra slutsatser kring vilka insatser som skulle kunna genomföras. Hit hör att berättiga sitt ändå högre pris, men också utforma ett bättre svar på miljöfrågorna och en uppväxling av positioneringsaktiviteterna. / How do potential customers reason concerning the purchase of a product supplied? This is one of the main issues for a marketer, but also an issue that is current in our market economy at large. Consumer behaviour is a given field of business economy. But how does this work when the consumer is a company? What marketing efforts should be implemented based on these new findings? This is the starting point of this essay. To answer these questions, a new consumer model, has therefore, been developed, which is based on existing theories of consumer behaviour and in particular the so-called black box model. The goal of the model is to shed light on the relevant aspects and processes that are reviewed and considered in connection to the purchase of an enterprise. The study relates to the purchase of coffee machines to the limited prospects for the coffee and coffee machine supplier Coffee Premium, with an emphasis on large companies in the Stockholm region. Information has been collected using questionnaires by mail. Based on our empirical data, we can assume that price is the absolutely most governing factor for the group. They are however willing to pay for more if this "more" is defined and demanded. It does not seem as a better taste and the ability to strengthen the brand are aspects considered as such but rather aspects as quality and durability. Furthermore, we can also assume that the purchase is almost always done through tenders. Based on this we are able to draw a number of conclusions about what actions that could be implemented. These include, for example, to review the pricing, combined with the aim to justify the higher prices, but also design a better response to environmental issues and an up shift of positioning activities.
4

Black-Box Model Development of the JAS 39 Gripen Fuel Tank Pressurization System : Intended for a Model-Based Diagnosis System / Black-box-modellering av tanktrycksättning hos bränslesystemet i JAS 39 Gripen : Avsedd för ett modellbaserat diagnossystem

Kensing, Vibeke January 2002 (has links)
The objective with this thesis is to build a Black-Box model of the tank pressurization system in JAS 39 Gripen. This model is intended to be used in an existing diagnosis system for the security control in the tank pressurization system. The tank pressurization system is a MIMO system. This makes the identification process more complicated when the best model is to be chosen. In this master's thesis the identification procedure for a MIMO system can be followed. Testing of the diagnosis system with the created Black-Box model shows that the model seems to be good enough. The diagnosis system takes the right decisions in the performed simulations. This shows that system identification might be a good alternative to physical modelling for a real-time model. The disadvantage with the Black-Box model is that it is less accurate in steady-state than the physical model used before is. The advantage is that it is faster than the physical model. The diagnosis system and the model developed in this thesis are not directly applicable on the real system today. The model has to be redesigned on the real system, this is also the case for the diagnosis system. The diagnosis system also has to be redesigned, so general flight cases, not only the security control can be supervised. However, experiences and choices like input and output signals, and choice of sample interval can be reused from this thesis when a new model might be developed.
5

Black-Box Model Development of the JAS 39 Gripen Fuel Tank Pressurization System : Intended for a Model-Based Diagnosis System / Black-box-modellering av tanktrycksättning hos bränslesystemet i JAS 39 Gripen : Avsedd för ett modellbaserat diagnossystem

Kensing, Vibeke January 2002 (has links)
<p>The objective with this thesis is to build a Black-Box model of the tank pressurization system in JAS 39 Gripen. This model is intended to be used in an existing diagnosis system for the security control in the tank pressurization system. The tank pressurization system is a MIMO system. This makes the identification process more complicated when the best model is to be chosen. In this master's thesis the identification procedure for a MIMO system can be followed. Testing of the diagnosis system with the created Black-Box model shows that the model seems to be good enough. The diagnosis system takes the right decisions in the performed simulations. This shows that system identification might be a good alternative to physical modelling for a real-time model. The disadvantage with the Black-Box model is that it is less accurate in steady-state than the physical model used before is. The advantage is that it is faster than the physical model. The diagnosis system and the model developed in this thesis are not directly applicable on the real system today. The model has to be redesigned on the real system, this is also the case for the diagnosis system. The diagnosis system also has to be redesigned, so general flight cases, not only the security control can be supervised. However, experiences and choices like input and output signals, and choice of sample interval can be reused from this thesis when a new model might be developed.</p>
6

Business Incubators: Wind Turbines of Entrepreneurship? : A qualitative study on University Business Incubators

Andersson, Louise, Müller, Sebastian January 2023 (has links)
Over the past three decades, interest in the topic of Business Incubation and more specifically University Business Incubation, has increased, due to its potential to encourage entrepreneurial activities, which initiate innovation and economic development. The literature on entrepreneurship devotes significant attention to BI as a tool for supporting entrepreneurs in overcoming difficulties associated with starting a business. Meanwhile, the fact that incubators themselves are vulnerable to different challenges needs to be sufficiently highlighted in the research currently in publication. By adopting an incubator’s perspective on developing entrepreneurs and, therefore, its dynamics that form new ventures, this qualitative study has focused on difficulties adjacent to the administration of the incubator. By building on the Black Box model of incubation, the Triad model, as well as Institutionalized entrepreneurship, the researchers have contributed to the phenomena of UBIs, and the many challenges they encounter when incubating business tenants. The thesis has successfully confirmed the inherent value of ensuring the financial viability of publicly financed incubators while shedding light on the challenges involved in achieving self-sufficiency. This examination has delved into the acquisition of government funds by incubators and explored the opportunities and constraints accompanying such support. Building on existing literature, which identifies sustainability and growth as key indicators, this study has provided empirical evidence and analysis that underscores the detrimental impact on the incubator's core mission when these criteria are not maintained.
7

Modellierung dynamischer Prozesse mit radialen Basisfunktionen / Modeling of dynamical processes using radial basis functions

Dittmar, Jörg 20 August 2010 (has links)
No description available.
8

Contribution des technologies CPL et sans fil à la supervision des réseaux de distribution d'électricité / Contribution of PLC and wireless technologies to supervision of electric distribution networks

Lefort, Romain 03 February 2015 (has links)
Le déploiement d'une infrastructure de supervision permet une gestion plus intelligente des réseaux de distribution d'électricité comparé à un renforcement traditionnel pour répondre aux nouveaux enjeux de la maitrise de l'énergie (Consommations, EnR, VE, ...). Pour acheminer les données, les Courants Porteurs en Ligne (CPL) possèdent un atout majeur. En effet, cette technologie permet de superposer un signal de plus haute fréquence au signal électrique 50/60 Hz. Toutefois, le support de transmission est difficile et non maîtrisable. Ces travaux de recherche ont pour objectif d'apporter une contribution à cette problématique par l'élaboration d'une plateforme de simulation des réseaux pour des fréquences allant jusqu'à 1 MHz dans un but de transmission de données. Des éléments clés des réseaux sont traités de façon séparés puis assemblés pour estimer les performances des CPL « Outdoor » actuels. La variation du comportement des réseaux en fonction du temps et de la fréquence, en particulier des perturbations en tête d'installation clients sur 24h est étudiée. Les transformateurs entre les réseaux HTA et BT sont modélisés sous la forme d'un « modèle à constantes localisées » et d'un « modèle boite noire ». Les deux modèles sont appliqués sur un transformateur H61 100 kVA. Par la suite, une modélisation des câbles de distribution est proposée sous forme d'un « modèle cascadé ». Celle-ci est appliquée sur un câble souterrain BT. Chaque modèle est obtenu à l'aide de mesures d'impédances, et validé par des mesures de transmissions. Pour compléter, une étude préliminaire sur les communications radio mobile est réalisée pour la supervision des réseaux de distribution. / Establishing a supervisory infrastructure allows a better smart management than an expensive strengthening of distribution network to respond to new constraints at the energies control (Consumption, REN, EV ...). To transmit data, Power Line Communication (PLC) technologies present an advantage in this context. In fact, it enables a superposition of High Frequency (HF) signals on electrical signal 50/60 Hz. However, electric networks have not been developed to this application because of difficult propagation conditions. This research work makes a contribution to develop a simulation platform in objective to transmit data to 1 MHz. In first time, each network element is studied singly and in second time, together, to estimate "Outdoor PLC" transmission performance. The first element studied is the networks variation in function of frequency and time. Several 24h disturbance measurements on LV customers are presented. The second element is the transformers which established connection between Medium Voltage (MV) and Low Voltage (LV). The proposed modeling method is based on a "lumped model" and a "black box model". These models are applied to a 100 kVA H61 transformer most commonly used by French distribution system operator in rural and suburban networks. The third element is the power line used in MV and LV networks. The proposed modeling method is based on a "cascaded model" from the theory of transmission line. This model is applied to one power line used in LV underground network. Each model is obtained from various impedance measurements. To complete, an introductory study on mobile radio communication is performed to remote network distribution.
9

Combined Actuarial Neural Networks in Actuarial Rate Making / Kombinerade aktuariska neurala nätverk i aktuarisk tariffanalys

Gustafsson, Axel, Hansén, Jacob January 2021 (has links)
Insurance is built on the principle that a group of people contributes to a common pool of money which will be used to cover the costs for individuals who suffer from the insured event. In a competitive market, an insurance company will only be profitable if their pricing reflects the covered risks as good as possible. This thesis investigates the recently proposed Combined Actuarial Neural Network (CANN), a model nesting the traditional Generalised Linear Model (GLM) used in insurance pricing into a Neural Network (NN). The main idea of utilising NNs for insurance pricing is to model interactions between features that the GLM is unable to capture. The CANN model is analysed in a commercial insurance setting with respect to two research questions. The first research question, RQ 1, seeks to answer if the CANN model can outperform the underlying GLM with respect to error metrics and actuarial model evaluation tools. The second research question, RQ 2, seeks to identify existing interpretability methods that can be applied to the CANN model and also showcase how they can be applied. The results for RQ 1 show that CANN models are able to consistently outperform the GLM with respect to chosen model evaluation tools. A literature search is conducted to answer RQ 2, identifying interpretability methods that either are applicable or are possibly applicable to the CANN model. One interpretability method is also proposed in this thesis specifically for the CANN model, using model-fitted averages on two-dimensional segments of the data. Three interpretability methods from the literature search and the one proposed in this thesis are demonstrated, illustrating how these may be applied. / Försäkringar bygger på principen att en grupp människor bidrar till en gemensam summa pengar som används för att täcka kostnader för individer som råkar ut för den försäkrade händelsen. I en konkurrensutsatt marknad kommer försäkringsbolag endast vara lönsamma om deras prissättning är så bra som möjligt. Denna uppsats undersöker den nyligen föreslagna Combined Actuarial Neural Network (CANN) modellen som bygger in en Generalised Linear Model (GLM) i ett neuralt nätverk, i en praktiskt och kommersiell försäkringskontext med avseende på två forskningsfrågor. Huvudidén för en CANN modell är att fånga interaktioner mellan variabler, vilket en GLM inte automatiskt kan göra. Forskningsfråga 1 ämnar undersöka huruvida en CANN modell kan prestera bättre än en GLM med avseende på utvalda statistiska prestationsmått och modellutvärderingsverktyg som används av aktuarier. Forskningsfråga 2 ämnar identifiera några tolkningsverktyg som kan appliceras på CANN modellen samt demonstrera hur de kan användas. Resultaten för Forskningsfråga 1 visar att CANN modellen kan prestera bättre än en GLM. En literatursökning genomförs för att svara på Forskningsfråga 2, och ett antal tolkningsverktyg identifieras. Ett tolkningsverktyg föreslås också i denna uppsats specifikt för att tolka CANN modellen. Tre av tolkningsverktygen samt det utvecklade verktyget demonstreras för att visa hur de kan användas för att tolka CANN modellen.
10

Combined Actuarial Neural Networks in Actuarial Rate Making / Kombinerade aktuariska neurala nätverk i aktuarisk tariffanalys

Gustafsson, Axel, Hansen, Jacob January 2021 (has links)
Insurance is built on the principle that a group of people contributes to a common pool of money which will be used to cover the costs for individuals who suffer from the insured event. In a competitive market, an insurance company will only be profitable if their pricing reflects the covered risks as good as possible. This thesis investigates the recently proposed Combined Actuarial Neural Network (CANN), a model nesting the traditional Generalised Linear Model (GLM) used in insurance pricing into a Neural Network (NN). The main idea of utilising NNs for insurance pricing is to model interactions between features that the GLM is unable to capture. The CANN model is analysed in a commercial insurance setting with respect to two research questions. The first research question, RQ 1, seeks to answer if the CANN model can outperform the underlying GLM with respect to error metrics and actuarial model evaluation tools. The second research question, RQ 2, seeks to identify existing interpretability methods that can be applied to the CANN model and also showcase how they can be applied. The results for RQ 1 show that CANN models are able to consistently outperform the GLM with respect to chosen model evaluation tools. A literature search is conducted to answer RQ 2, identifying interpretability methods that either are applicable or are possibly applicable to the CANN model. One interpretability method is also proposed in this thesis specifically for the CANN model, using model-fitted averages on two-dimensional segments of the data. Three interpretability methods from the literature search and the one proposed in this thesis are demonstrated, illustrating how these may be applied. / Försäkringar bygger på principen att en grupp människor bidrar till en gemensam summa pengar som används för att täcka kostnader för individer som råkar ut för den försäkrade händelsen. I en konkurrensutsatt marknad kommer försäkringsbolag endast vara lönsamma om deras prissättning är så bra som möjligt. Denna uppsats undersöker den nyligen föreslagna Combined Actuarial Neural Network (CANN) modellen som bygger in en Generalised Linear Model (GLM) i ett neuralt nätverk, i en praktiskt och kommersiell försäkringskontext med avseende på två forskningsfrågor. Huvudidén för en CANN modell är att fånga interaktioner mellan variabler, vilket en GLM inte automatiskt kan göra. Forskningsfråga 1 ämnar undersöka huruvida en CANN modell kan prestera bättre än en GLM med avseende på utvalda statistiska prestationsmått och modellutvärderingsverktyg som används av aktuarier. Forskningsfråga 2 ämnar identifiera några tolkningsverktyg som kan appliceras på CANN modellen samt demonstrera hur de kan användas. Resultaten för Forskningsfråga 1 visar att CANN modellen kan prestera bättre än en GLM. En literatursökning genomförs för att svara på Forskningsfråga 2, och ett antal tolkningsverktyg identifieras. Ett tolkningsverktyg föreslås också i denna uppsats specifikt för att tolka CANN modellen. Tre av tolkningsverktygen samt det utvecklade verktyget demonstreras för att visa hur de kan användas för att tolka CANN modellen.

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