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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.
31

Análise, design e inovação de modelos de negócios para servitização / Analysis, design and innovation of business models for servitization.

Renato Machado Costa 13 June 2017 (has links)
Empresas de manufatura tradicionalmente concentram os seus esforços em concepção, desenvolvimento, fabricação e comercialização de produtos físicos. No entanto, alguns fabricantes têm alterado suas estratégias de negócio, complementando a venda de produtos com o fornecimento de serviços, incorporando conhecimentos e atividades associados ao seu uso, e gerando maior percepção de valor por parte dos seus clientes. Com isso, a competição estratégica por meio de serviços tem se tornado uma marca distintiva das empresas de manufatura inovadoras, proporcionando à empresa um meio robusto para proteger o seu mercado dos concorrentes. Assim, observa-se um interesse crescente em pesquisas sobre o papel dos serviços para sustentar a competitividade da indústria. Abordagens orientadas a serviço, que incorporam esta mudança de foco do negócio, da oferta de produtos isolados para soluções integradas, têm sido tratadas na comunidade acadêmica como servitização, e tipicamente acarretam inovações no modelo de negócios (MN) da empresa. O objetivo deste trabalho é investigar como as empresas podem promover inovações em seus MNs para suportar suas estratégias de servitização, e propor um conjunto de artefatos para apoiá-las na implantação destas estratégias, a partir do seguinte problema de pesquisa: \"Como inovar o MN de uma empresa que adota a estratégia de servitização?\", que se desdobra nas seguintes questões: (i) quais são os principais fatores motivadores para uma empresa adotar a estratégia de servitização?; (ii) como representar o MN de uma empresa incorporando a lógica dominante de serviço, mais adequada para servitização?; (iii) como inovar o MN de uma empresa para implantar sua estratégia de servitização?; e (iv) como aplicar os artefatos propostos para apoiar a implantação da estratégia de servitização em uma empresa? Realiza-se uma pesquisa de natureza exploratória e prescritiva, baseada no método design scienceresearche amparada por uma revisão sistemática da literatura sobre os temas correlatos, visando propor artefatos em resposta às questões colocadas. A demonstração de um dos artefatos propostos é feita com suporte de um estudo de caso em uma empresa multinacional, fabricante de equipamentos médicos, seguida por uma avaliação empírica desta demonstração, suportada pelo método thinkingaloud. A partir das quatro questões de pesquisa, são obtidos os seguintes resultados: (i) identificação, análise e categorização dos principais fatores motivadores para adoção da servitização; (ii) proposição de uma arquitetura de MN incorporando a lógica dominante de serviço, para facilitar o estudo da servitização; (iii) proposição de um processo de inovação do MN da empresa, para implantar a servitização. e (iv) demonstração e avaliação da arquitetura proposta de MN para servitização. A pesquisa oferece contribuições à literatura de MN e servitização, e aos gestores de empresas, propondo os artefatos canvas do modelo de negócios para servitização (CMNS) e o processo IPIDI para inovação do MN para servitização, além de contribuições metodológicas relativas a design scienceresearch e thinking aloud. / Manufacturing companies traditionally are focused on designing, developing, manufacturing and marketing physical products. However, some manufacturers are changing their business strategies, complementing the sale of products by providing services, adding knowledge and activities associated with their use, and creating a higher perception of value by their customers.Strategic competition through service delivery has become a hallmark of the innovative manufacturing companies, providing the companies with a robust means to protect their market from competitors. Thus, there is a growing interest in researching the role of services in sustaining the competitiveness of manufacturing industry.Service-oriented approaches, which incorporate this shift in business\' focus from offering isolated products, to proposing integrated solutions, have been addressed in the literature as servitization, and typically entail innovations in the company\'s business model (BM). The goal of this research is investigating how companies can promote transformations in their BMs to support their servitization strategies, and proposing a set of artifacts to support them in the implementation of these strategies, since the following research problem: \"How to innovate the BM of a company which adopts the servitization strategy? \", which unfolds in the following questions: (i) what are the main motivating factors for a company to adopt the servitization strategy?; (ii) how to represent the BM of a company incorporating the service-dominant logic, more suitable for servitization?; (iii) how to innovate a company\'s BM to implement its servitization strategy ?; and (iv) how to apply the proposed artifacts to support the implementation of the servitization strategy in a company? An exploratory and prescriptive research is carried out, based on the design science research methodology, and supported by a systematic literature review on the related subjects, aiming at proposing artifacts in response to the questions posed. The demonstration of the proposed artifacts is done by means of a case study in a multinational company, which manufactures medical devices, followed by an assessment of this demonstration, supported by the thinking aloud method. From the four research questions, the following results are obtained: (i) identification, analysis and categorization of the main motivating factors for servitization adoption; (ii) proposing a BM architecture according to the service-dominant logic, to help the servitization study; (iii) proposing an innovation process for the company\'s BM, to implement the servitization; and (iv) demonstration and assessment of the proposed BM architecture for servitization. The research offers contributions to the literature of BM and servitization, and to practitioners, proposing the artifacts business model canvas for servitization (BMCS) and the IPIDI process for innovation of BM for servitization, besides some methodological contributions related to design science research and thinking aloud.
32

Relaxace smykového napětí asfaltových pojiv v DSR / Shear stress relaxation of bituminous binders in DSR

Musil, Vladimír January 2015 (has links)
The thesis describes the relaxation properties of bituminous binders determined in dynamic shear rheometer (DSR). Paving bitumen, polymer modified bitumen (PMB) and crumb rubber modified bitumen (CRmB) were chosen for comparison. In order to describe the effects of ageing on asphalt binders relaxation properties, the laboratory simulation of ageing using RTFOT and 3xRTFOT method was performed. For each binder were simultaneously conducted tests of needle penetration, softening point and elastic recovery. Selected bitumens were used for the production of asphalt mixtures. The low-temperature properties tests (TSRST) were performed for these mixtures, when the results were compared to the relaxation properties of binders determined in the DSR.
33

Stárnutí asfaltových pojiv / Ageing of asphalt binders

Střasáková, Monika January 2016 (has links)
The theoretical part of this thesis describes the rheology of bituminous binders, aging of asphalt binders and laboratory methods simulating short and long term aging. The following describes an empirical tests (needle penetration, softening point ring ball method) and functional tests (complex shear modulus and phase angle, dynamic viscosity), which are performed in the dynamic shear rheometer. At the end of this section, laboratory aging of bituminous binders using method RTFOT and method RTFOT + PAV is described in more detail. In the practical part of this thesis, the results of all tests performed on the binders aged using RTFOT + PAV are introduced and compared with results of properties of non-aged binders and binders aged by 3xRTFOT.
34

[en] ELABORATION OF A DECISION DIAGRAM AS AN ARTIFACT TO ASSIST IN THE DECISION OF THE INVENTORY CONTROL METHOD OF AN OIL AND GAS COMPANY / [pt] ELABORAÇÃO DE UM DIAGRAMA DE DECISÃO COMO ARTEFATO PARA AUXILIAR NA DECISÃO DO MÉTODO DE CONTROLE DE ESTOQUE DE UMA EMPRESA DO RAMO DE PETRÓLEO E GÁS

CESAR CARDOZO AMARAL 23 December 2020 (has links)
[pt] A Gestão de Estoque eficiente permeia a escolha do método de controle mais adequado, principalmente em empresas que apresentem grande variedade de itens em estoque, quando a definição de métodos diferentes para cada item pode resultar em ganhos pela redução de excessos ou faltas, assim como pela redução de custos administrativos dessa gestão. A empresa estudada se insere nesse contexto, pois apresenta excesso de materiais em estoque, bem como faltas de alguns itens, gerando prejuízos financeiros decorrentes da má gestão de seu estoque. Assim, por adotar a mesma política de controle de estoque para todos os itens, que abrangem de materiais de administração predial a equipamentos de exploração de petróleo e gás, essa empresa se depara com a necessidade de implementar controles de estoque mais adequados para cada um desses itens. Desse modo, este trabalho propõe responder a seguinte pergunta-chave de estudo: Qual a política de gestão de estoques mais adequada para cada produto analisado? Para responder a essa pergunta, o trabalho propõe a elaboração de um Diagrama de Decisão que auxilie na tomada dessa decisão. Para tanto, busca classificar esses SKU quanto a Curva ABC para valor (RS), volume consumido e criticidade, sendo esta última definida com apoio do Analytic Hierarchy Process (AHP). Além disso, analisa as distribuições de demanda e de lead time de cada SKU como parâmetros para auxiliar nessa decisão, formando um diagrama onde os nós representam esses parâmetros (Curva ABC, Demanda e Lead Time) e os caminhos correspondem as classificações internas de cada um desse parâmetros, apontando, ao final de cada caminho, qual o melhor controle de estoque para o SKU analisado considerando o Kanban e o MRP como alternativas. Aplicou-se a Design Science Research (DSR) como método de estudo. Com a aplicação desse método pretende-se que o Diagrama proposto seja um artefato capaz de atender as diferentes áreas de negócio da empresa, contribuindo para disseminação de uma ferramenta padrão para a tomada de decisão quanto ao método de controle de estoque a ser empregado para cada SKU. Assim, espera-se que o artefato proposto posso contribuir com todas as áreas da empresa, ampliando o conhecimento gerado na área de negócio delimitada para este estudo. Por fim, o trabalho contribuiu com o desenvolvimento de uma ferramenta capaz de atender as necessidades da empresa quanto a adoção de diferentes métodos de controle de estoques, indiferentemente da área de negócio a qual se aplica. Além disso, na área delimitada para implementação deste estudo, a aplicação desse diagrama obteve a redução do excesso e das faltas para os SKU analisados, bem como apresentou forte potencial de redução de custos administrativos em função da possibilidade de adotar métodos mais simples de controle de estoque para alguns itens. / [en] Efficient Inventory Management permeates the choice of the most appropriate control method, especially in companies that have a wide variety of items in stock, when the definition of different methods for each item can result in gains by reducing excesses or shortages, as well as by reduction of administrative costs of this management. The studied company is part of this context, as it presents an excess of materials in stock, as well as shortages of some items, generating financial losses resulting from the mismanagement of its stock. Thus, by adopting the same inventory control policy for all items, which range from building management materials to oil and gas exploration equipment, this company is faced with the need to implement more adequate inventory controls for each of these tems. Thus, this paper proposes to answer the following key study question: What is the most adequate inventory management policy for each product analyzed? To answer this question, this work proposes the elaboration of a Decision Diagram that helps in making that decision. Therefore, it seeks to classify these SKU as the ABC Curve for value (Rs), volume consumed and criticality, the latter being defined with the support of the Analytic Hierarchy Process (AHP). In addition, it analyzes the demand and lead time distributions of each SKU as parameters to assist in this decision, forming a diagram where the nodes represent these parameters (ABC curve, Demand and Lead Time) and the paths correspond to the internal classifications of each one of these parameters, pointing, at the end of each path, which is the best stock control for the SKU analyzed considering Kanban and MRP as alternatives. Design Science Research (DSR) was applied as a study method. With the application of this method, the proposed Diagram is intended to be an artifact capable of serving the different business areas of the company, contributing to the dissemination of a standard tool for decision making regarding the inventory control method to be employed for each SKU. Thus, it is expected that the proposed artifact can contribute to all areas of the company, expanding. Finally, the work contributed to the development of a tool capable of meeting the company s needs regarding the adoption of different inventory control methods, regardless of the business area to which it applies. In addition, in the area defined for the implementation of this study, the application of this diagram obtained the reduction of excess and shortages for the SKUs analyzed, as well as presenting a strong potential for reducing administrative costs due to the possibility of adopting simpler methods of controlling stock for some items.
35

Design and evaluation of security mechanism for routing in MANETs : elliptic curve Diffie-Hellman cryptography mechanism to secure Dynamic Source Routing protocol (DSR) in Mobile Ad Hoc Network (MANET)

Almotiri, Sultan H. January 2013 (has links)
Ensuring trustworthiness through mobile nodes is a serious issue. Indeed, securing the routing protocols in Mobile Ad Hoc Network (MANET) is of paramount importance. A key exchange cryptography technique is one such protocol. Trust relationship between mobile nodes is essential. Without it, security will be further threatened. The absence of infrastructure and a dynamic topology changing reduce the performance of security and trust in mobile networks. Current proposed security solutions cannot cope with eavesdroppers and misbehaving mobile nodes. Practically, designing a key exchange cryptography system is very challenging. Some key exchanges have been proposed which cause decrease in power, memory and bandwidth and increase in computational processing for each mobile node in the network consequently leading to a high overhead. Some of the trust models have been investigated to calculate the level of trust based on recommendations or reputations. These might be the cause of internal malicious attacks. Our contribution is to provide trustworthy communications among the mobile nodes in the network in order to discourage untrustworthy mobile nodes from participating in the network to gain services. As a result, we have presented an Elliptic Curve Diffie-Hellman key exchange and trust framework mechanism for securing the communication between mobile nodes. Since our proposed model uses a small key and less calculation, it leads to a reduction in memory and bandwidth without compromising on security level. Another advantage of the trust framework model is to detect and eliminate any kind of distrust route that contain any malicious node or suspects its behavior.
36

TRASMISSION CONTROL PROTOCOL (TCP) PERFORMANCE EVALUATION IN MANET / TRASMISSION CONTROL PROTOCOL (TCP) PERFORMANCE EVALUATION IN MANET

Ijaz, Muhammad January 2009 (has links)
Mobile Ad hoc network routing protocols have been divided in several different categories such as Reactive and Proactive Routing Protocol. The performances of these categories are evaluated in different scenario with TCP variants. We present a comprehensive TCP performance evaluation study to understand the nature of the TCP performance in different scenarios with variable amount of payload and number of nodes. The traffic consists of three different packet sizes i.e. 512, 1000, 1500 bytes each. Three different routing protocols (AODV, DSR and TORA) are to be evaluated with three different TCP variants (Tahoe, Reno and New Reno) in three different scenarios having 3, 5 and 8 nodes. The performances parameters on the basis of which routing protocols are to be graded are mainly throughput, congestion window and delay. Conclusions are drawn based on the simulation results and the comparisons between them have been elaborated. / N.W.F.P PAKISTAN. Mobile no: 0092-3339173438
37

Multiplexing NFC Antennas : An evaluation of the technique and its limitations / Multiplexande NFC Antenner

Gustafsson, Viktor, Ottosson, Per January 2023 (has links)
Introduction This study aims to investigate the possibility of driving multiple NFC antennas with a single NFC-controller by using a multiplexer. An artifact was developed and experiments were conducted in order to evaluate the design choice and in addition, to observe the impact of a multiplexer in an NFC system with respect to the number of successful tag detections, bit error rate (BER), the utilization of automatic antenna tuning (AAT) and the physical distance to the NFC tag. Data collected from the experiments was analyzed, and the results were discussed. The purpose of the thesis was concretized by formulating three research questions: [RQ1] How can the design proposed in the problem statement be implemented? [RQ2] How does the multiplexer impact the system’s ability to detect an NFC tag and read its contents at different distances? [RQ3] To which degree does the AAT-technology compensate for the issues caused by the multiplexer? Method This research has been conducted according to the design science research (DSR) methodology. DSR is a well-established methodology and suits the nature of this research, therefore it is used to answer the research questions. Findings The thesis demonstrates a viable solution using a multiplexer in NFC systems, with reduced detection distance as a factor to consider. The impact of AAT remains inconclusive, requiring further research. Implications This study shows that using a multiplexer in NFC systems can save costs and space, leading to more affordable and compact devices. It enables scalable, advanced NFC devices for diverse applications, encouraging wider adoption. However, developers must consider the impact of a multiplexer on detection distance when designing NFC-based applications Limitations This study has certain limitations. It focuses on a particular multiplexer and NFC antenna type, and specific testing conditions. It does not delve into the potential profitability, diverse applications, security or encryption concerns, compatibility with other devices, compliance with regulations, or hands-on verification of part connectivity.
38

Design and Evaluation of Security Mechanism for Routing in MANETs. Elliptic Curve Diffie-Hellman cryptography mechanism to secure Dynamic Source Routing protocol (DSR) in Mobile Ad Hoc Network (MANET).

Almotiri, Sultan H. January 2013 (has links)
Ensuring trustworthiness through mobile nodes is a serious issue. Indeed, securing the routing protocols in Mobile Ad Hoc Network (MANET) is of paramount importance. A key exchange cryptography technique is one such protocol. Trust relationship between mobile nodes is essential. Without it, security will be further threatened. The absence of infrastructure and a dynamic topology changing reduce the performance of security and trust in mobile networks. Current proposed security solutions cannot cope with eavesdroppers and misbehaving mobile nodes. Practically, designing a key exchange cryptography system is very challenging. Some key exchanges have been proposed which cause decrease in power, memory and bandwidth and increase in computational processing for each mobile node in the network consequently leading to a high overhead. Some of the trust models have been investigated to calculate the level of trust based on recommendations or reputations. These might be the cause of internal malicious attacks. Our contribution is to provide trustworthy communications among the mobile nodes in the network in order to discourage untrustworthy mobile nodes from participating in the network to gain services. As a result, we have presented an Elliptic Curve Diffie-Hellman key exchange and trust framework mechanism for securing the communication between mobile nodes. Since our proposed model uses a small key and less calculation, it leads to a reduction in memory and bandwidth without compromising on security level. Another advantage of the trust framework model is to detect and eliminate any kind of distrust route that contain any malicious node or suspects its behavior.
39

EFFECT OF CHEMICAL SOLVENTS ON RHEOLOGICAL PROPERTIES OF RECOVERED ASPHALT BINDERS

AbuHassan, Yazeed 18 November 2016 (has links)
No description available.
40

Design, Implementation and Analysis of Wireless Ad Hoc Messenger

Cho, Jin-Hee 12 August 2004 (has links)
Popularity of mobile devices along with the presence of ad hoc networks requiring no infrastructure has contributed to recent advances in the field of mobile computing in ad hoc networks. Mobile ad hoc networks have been mostly utilized in military environments. The recent advances in ad hoc network technology now introduce a new class of applications. In this thesis, we design, implement and analyze a multi-hop ad hoc messenger application using Pocket PCs and Microsoft .Net Compact Framework. Pocket PCs communicate wirelessly with each other using the IEEE 802.11b technology without the use of an infrastructure. The main protocol implemented in this application is based on Dynamic Source Routing (DSR), which consists of two important mechanisms, Route Discovery and Route Maintenance. We adopt DSR since DSR operates solely based on source routing and "on-demand" process, so each packet does not have to transmit any periodic advertisement packets or routing information. These characteristics are desirable for the ad hoc messenger application for which a conversation is source-initiated on-demand. To test our application easily, we have developed a testing strategy by which a mobility configuration file is pre-generated describing the mobility pattern of each node generated based on the random waypoint mobility model. A mobility configuration file thus defines topology changes at runtime and is used by all nodes to know whether they can communicate with others in a single-hop or multi-hops during an experimental run. We use five standard metrics to test the performance of the wireless ad hoc messenger application implemented based on DSR, namely, (1) average latency to find a new route, (2) average latency to deliver a data packet, (3) delivery ratio of data packets, (4) normalized control overhead, and (5) throughput. These metrics test the correctness and efficiency of the wireless ad hoc messenger application using the DSR protocol in an 802.11 ad hoc network that imposes limitations on bandwidth and resources of each mobile device. We test the effectiveness of certain design alternatives for implementing the ad hoc messenger application with these five metrics under various topology change conditions by manipulating the speed and pause-time parameters in the random waypoint model. The design alternatives evaluated include (1) Sliding Window Size (SWS) for end-to-end reliable communication control; (2) the use of per-hop acknowledgement packets (called receipt packets) deigned for rapid detection of route errors by intermediate nodes; and (3) the use of cache for path look-up during route discovery and maintenance. Our analysis results indicate that as the node speed increases, the system performance deteriorates because a higher node speed causes the network topology to change more frequently under the random waypoint mobility model, causing routes to be broken. On the other hand, as the pause time increases, the system performance improves due to a more stable network topology. For the design alternatives evaluated in our wireless ad hoc messenger, we discover that as SWS increases, the system performance also increases until it reaches an optimal SWS value that maximizes the performance due to a balance of a higher level of data parallelism introduced and a higher level of medium contention in 802.11 because of more packets being transmitted simultaneously as SWS increases. Beyond the optimal SWS, the system performance deteriorates as SWS increases because the heavy medium contention effect outweighs the benefit due to data parallelism. We also discover that the use of receipt packets is helpful in a rapidly changing network but is not beneficial in a stable network. There is a break-even point in the frequency of topology changes beyond which the use of receipt packets helps quickly detect route errors in a dynamic network and would improve the system performance. Lastly, the use of cache is rather harmful in a frequently changing network because stale information stored in the cache of a source node may adversely cause more route errors and generate a higher delay for the route discovery process. There exists a break-even point beyond which the use of cache is not beneficial. Our wireless ad hoc messenger application can be used in a real chatting setting allowing Pocket PC users to chat instantly in 802.11 environments. The design and development of the dynamic topology simulation tool to model movements of nodes and the automatic testing and data collection tool to facilitate input data selection and output data analysis using XML are also a major contribution. The experimental results obtained indicate that there exists an optimal operational setting in the use of SWS, receipt packets and cache, suggesting that the wireless ad hoc messenger should be implemented in an adaptive manner to fine-tune these design parameters based on the current network condition and performance data monitored to maximize the system performance. / Master of Science

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