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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

Uso da tecnologia Weigh-in-Motion para a caracterização do tráfego rodoviário e do excesso de carga em veí­culos comerciais. / Use of the Weigh-in-Motion technology for the characterization of road traffic and overloading in commercial vehicles.

Mariana Bosso 04 July 2018 (has links)
A caracterização do tráfego rodoviário é de grande importância para o dimensionamento de pavimentos, bem como para a garantia de sua vida útil, sendo a carga aplicada pelo tráfego uma das maiores responsáveis pelos danos na estrutura. Com o objetivo de garantir a durabilidade dos pavimentos, sistemas Weigh-in-Motion (WIM) podem ser utilizados para coleta de informações sobre os veículos que trafegam em uma rodovia. Propôs-se neste estudo caracterizar o tráfego a partir da avaliação contínua das solicitações de carga na BR-381, sentido Sul, por meio da coleta de dados de Sistema WIM. A partir da análise dos dados coletados entre setembro de 2015 e fevereiro de 2017, observou-se que aproximadamente 85% dos veículos comerciais trafegam na faixa de rolamento mais solicitada (faixa 2). Com relação ao volume de veículos comerciais, pôde-se constatar a presença de uma maior quantidade de veículos durante os dias úteis quando comparados aos finais de semana. Além das variações com relação ao dia da semana, o volume de tráfego também apresenta particularidades com relação às distribuições horárias. Foram obtidas e analisadas as distribuições de carga para cada tipo de eixo das 15 categorias de veículos comerciais mais frequentes (representando 97,3% do tráfego comercial registrado). Com base na Legislação Brasileira vigente, quantificou-se o excesso de carga praticado na rodovia, onde foram identificados 23,7% dos veículos com excesso. Notou-se que a maioria dos excessos se encontram na faixa de até 10% dos respetivos limites legais, indicando que muitos transportadores carregam seus veículos considerando a tolerância como um ganho real de sobrecarga. Um método para identificação de padrões de viagem dos veículos com excesso foi proposto, que se baseia nas árvores de classificação e regressão (Classification and Regression Tree Analysis - CART), uma ferramenta analítica. Por fim, os dados de tráfego foram correlacionados com os defeitos observados no trecho experimental construído logo após o sistema WIM, onde se simulou a redução da vida útil de estruturas de pavimentos considerando diferentes cenários de carga, sendo eles: (i) tráfego real; (ii) tráfego na tolerância (considerando a tolerância de 10%); e (iii) tráfego legal, concluindo-se que a prática do excesso de carga nas rodovias penaliza o transporte rodoviário ao acelerar a degradação das rodovias. / The traffic characterization is of great importance for pavement design, as well as for prediction of its remaining service life. In fact, traffic loading is one of the major contributors for the pavement deterioration. In order to ensure pavement durability, Weigh-in-Motion (WIM) systems can be used to collect traffic data. Therefore, this study was conducted to analyze the effect on the pavements of characterizing the traffic through a Weigh-in-Motion system installed between km 948 and 949 at the Brazilian Federal Highway BR-381. The analysis of the data collected from September 2015 to February 2017 shows that approximately 85% of commercial vehicles travel on the outside slow lane (lane 2). Regarding the volume of commercial vehicles, traffic volume was lower in weekends. In addition to the daily variations, traffic patterns also presented hourly variations. The axle load distributions were obtained and analyzed for the 15 more frequent commercial vehicle categories (representing 97.3% of all the commercial traffic registered). Based on the current Brazilian laws, the results from this study have indicated a significant percentage of violation involving overloaded heavy good vehicles in the highway (23.7%). In general, most axles exceed the legal limits up to 10%, indicating that many vehicles are loaded considering the tolerance as a real gain. A method to identify overloaded truck travel patterns and loading characteristics from available HS-WIM data was proposed. The method is based on Classification and Regression Tree Analysis (CART), an analytical tool. Finally, the traffic data were correlated with the distresses observed in the experimental section constructed closer to the WIM system, where it was simulated the reduction of the useful life of pavement structures considering different load scenarios: (i) real traffic; (ii) traffic in the tolerance (considering the tolerance of 10%); and (iii) legal traffic. it was concluded that the practice of overloading on highways penalizes road transport by accelerating road degradation.
32

Estudo da influência do levantamento de eixos em veículos comerciais no desempenho na frenagem e na estabilidade direcional / Study of commercial vehicles elevated axle influence on braking performance and on directional stability

Eduardo Piquera Vianna 22 March 2006 (has links)
Os sistemas que elevam os eixos dos veículos comerciais foram inicialmente desenvolvidos com o objetivo de economizar pneus. Até o final da década de 90, o uso destes sistemas era restrito, não causando um efeito estatístico sensível na segurança veicular. Devido a um acordo entre concessionárias rodoviárias e o governo, os veículos comerciais pagam nas praças de pedágio o valor correspondente ao número de eixos em contato com o solo naquele momento, minimizando as tarifas dos veículos que fazem uso deste sistema. Esta prática se difundiu rapidamente e poucos estudos técnicos foram realizados focando sua influência na segurança veicular. A elevação dos eixos altera de forma significativa a margem de estabilidade do veículo e a distribuição ideal das forças de frenagem, podendo elevar os riscos de acidentes. Este trabalho consiste num estudo aprofundado do desempenho dos veículos comerciais com estes sistemas de elevação de eixos, sob o ponto de vista técnico e operacional, focando a segurança veicular. Para tanto, são utilizados como metodologia modelos matemáticos já desenvolvidos na literatura científica em veículos exemplos. Parâmetros como a margem de estabilidade, gradiente de esterçamento, eficiência da frenagem dentre outros são analisados; também os efeitos na resposta direcional durante o período transitório em manobras e nos instantes iniciais da frenagem. As influências da elevação dos eixos são analisadas conforme normas e requisitos estabelecidos pela ABNT e ECE R13, inclusive anexo 10, pois a prática da elevação dos eixos pode estar infringindo requisitos impostos por estas normas. Como conclusão é visto que o levantamento dos eixos é prejudicial ao desempenho dinâmico do veículo. Em virtude disto, o seu uso deveria ser fundamentado tanto nas fases conceitual e de desenvolvimento quanto na legislação vigente no país. / The systems that elevate the axles of the commercial vehicles were initially developed with the objective of saving tires. The use of these systems was restricted, not causing a notable statistical effect in the vehicle safety. Due to an agreement between road concessionaires and the government, the commercial vehicles pay toll value according to the number of axles in contact with the soil on that moment, minimizing the taxes of the vehicles using this system. This practice was diffused quickly and few technical studies were accomplished focusing its influence in the vehicle safety. The elevated axles alters in a significant way the vehicle static margin of stability and the ideal distribution of the braking forces, increasing the accident risks. This work consist in deepened studies of the commercial vehicles with these systems of elevation of axles, of the technical and operational point of view, focusing the vehicle safety. For this is used as methodology mathematical models developed already in the scientific literature in vehicles examples. Parameters as the margin of stability, steer gradient, braking efficiency and others are analyzed. Likewise, the effects in the directional response during the transient maneuvers and in the initial instants of the braking. The influences of the elevation of the axes are analyzed according to norms and established requirements for ABNT and ECE R13, including annex 10, because the practice of the elevation of the axes can be infringing requirements imposed by these norms. As main conclusion these systems are prejudicial to vehicle dynamics and handling and its use could be anticipated in conceptual and design phase and in brazilian transport laws.
33

Energy Optimal Routing of Vehicle Fleet with Heterogeneous Powertrains

Arasu, Mukilan T. January 2019 (has links)
No description available.
34

Definition av näringslivstransporter ur ett trafikmätningsperspektiv / A Definition of Commercial Vehicle Transport from a Traffic Measurement Perspective

Olofsson, Josefin January 2021 (has links)
Kunskap om vägtrafikens sammansättning behövs för planering av relevanta åtgärder och utvärdering av framtida lösningar inom trafiksystemet. För att öka kunskapsunderlaget om trafikens tillstånd utvecklar Trafikverket Region Stockholm en mätplan för Stockholmsregionen som syftar till att genom mått och indikatorer bättre kunna förklara trafikläget och dess förändring. Behovet av att samordna transporter blir allt större i takt med att befolkningen ökar, men idag finns varierade möjligheter att kartlägga olika grupper av vägtrafiken. Näringslivstransporter pekas ut som ett av Trafikverkets målområden i mätplanen, inom vilka det finns behov av att öka kunskap och dataunderlag. I ett första steg att nå det målet behöver näringslivstransporter beskrivas genom en definition, vilket är det huvudsakliga syftet med detta examensarbete. Definitionen som formulerats, och som beskriver vad som bör betraktas som näringslivstransporter, baseras på information från litteratur och genom intervjuer där begreppet analyserats ur olika perspektiv. Resultatet visar att gruppen är bred och svår att kartlägga eftersom den innefattar en mängd olika transporttyper som genomförs med allt från personbil till stora lastbilar. Eftersom det finns en risk att näringslivstransporter som helhetsbegrepp kan bli begränsat i sin användning genom en för snäv definition har gruppen definierats med aktsamhet. Definitionen delas in i tre kategorier enligt följande: Näringslivstransport av gods, Näringslivstransport av personer och Näringslivstransport av tjänster. Eftersom kunskapsbristen om näringslivstransporter är stor och definitionen ska vara så anpassningsbar som möjligt görs ingen vidare indelning av de tre kategorierna, men exempel på vad varje kategori kan innehålla ges för att förklara hur definitionen kan tillämpas. Det är dock viktigt att poängtera att de olika kategorierna är i olika stort behov av ett ökat kunskapsunderlag baserat på deras omfattning och hur väl de kan kartläggas i olika mätmetoder. Utifrån definitionen genomfördes en dataanalys i syfte att undersöka hur stor del av näringslivstransporter som kan kartläggas i tillgängliga datakällor. Den data som studerades var MCS- och ANPR-data, samt en filminspelning av trafiken. Resultatet visar att det finns goda möjligheter att kategorisera olika typer av lastbilar som kan antas höra till näringslivstransporter genom framför allt ANPR-data, men en del av näringslivstransporter går endast att identifiera genom visuell information såsom logotyper i det filmade materialet. Förslag på vidare studier är att fortsatt kombinera tillgängliga mät- och kartläggningsmetoder, dels i syfte att härleda data till näringslivstransporter, dels för att undersöka vilken typ av information som idag inte kan erhållas om gruppen. Eftersom tidigare studier på näringslivstransporter som helhetsbegrepp är begränsade finns det även behov av att undersöka gruppen vidare, både i sin helhet och undergrupperna för sig. / Knowledge regarding the composition of road traffic is needed for the planning of relevant measures and evaluation of future infrastructure solutions in the transport system. In order to increase knowledge in this area, the Stockholm region of the Swedish Transport Administration is developing a measurement plan that aims to describe the status of the road traffic system and its development using a number of chosen measures and indicators. The need to coordinate transport is increasing with population growth, but today the opportunities to measure different transport categories varies. Commercial vehicles are identified as one of the target areas in the measurement plan, within which there is a need to increase knowledge and explore data sources for further analysis. A step towards achieving this goal is to define what is implied by the term commercial vehicles. This is the main aim of the thesis. The definition of commercial vehicles is based on information obtained from literature and interviews. This information has resulted is a categorization that includes a range of different types of transport. Measuring commercial vehicles is difficult as the definition includes transport carried out by passenger cars as well as trucks. As there is a risk that commercial vehicles as a group may be restricted by a definition that is too narrow, it must be carefully defined. The suggested definition divides commercial vehicles into three main categories: transport of goods, transport of people and transport of services. The aim of this definition is to make it adaptable to specific needs. Examples of what each category may contain, and how the definition can be applied are given in the report. It is important to point out that the different categories are in need of further study in order to increase the knowledge base. Based on the definition, a data analysis was carried out to investigate how commercial vehicles can be explained and measured using three available data sources. The data used included MCS (Motorway Control System), ANPR (Automatic Number Plate Recognition), and film recording. The results showed that there are good opportunities to categorize different types of trucks used for commercial purposes from the ANPR data in particular. However, some attributes of the group can only be identified through visual information such as logos from the film recordings. Proposals for further studies include the need to combine readily available measurement methods and data. Also, as previous studies on commercial vehicles are limited, there is also a need to investigate the group further, both in its entirety and the three categories separately.
35

What future for electric light commercial vehicles ? : a prospective economic and operational analysis of electric vans for business users, with a focus on urban freight / Quel avenir pour les véhicules utilitaires légers électriques ? : une analyse prospective du marché des vans électriques pour le transport de marchandises en ville

Camilleri, Pierre 26 October 2018 (has links)
Le marché des véhicules électriques est animé par une dynamique très positive. Il s'agit cependant essentiellement d'un marché de niche. Il est donc légitime de s’interroger quant à son avenir.D'une part, cette dynamique est portée par de fortes préoccupations environnementales et bénéficie d'un large soutien des autorités publiques. Les constructeurs automobiles ont ces dernières années fortement investi dans cette technologie, les progrès technologiques sont rapides et offrent des perspectives intéressantes.D'autre part, des subventions conséquentes sont aujourd’hui nécessaires pour permettre aux véhicules électriques d’être compétitifs. Il est inévitable que ces subventions diminuent si le marché grandit. Deux mécanismes opposés sont donc en jeu et rendent incertain le développement du marché des véhicules électriques pour les années à venir.Notre recherche propose d'analyser ces mécanismes pour les véhicules utilitaires légers, et plus particulièrement pour le transport urbain de marchandises. Les besoins des entreprises de transport de marchandises sont évalués à travers une quarantaine d'entretiens, menés dans quatre pays européens et analysés à la lumière de la théorie de la diffusion de l'innovation. Ces entretiens mettent en évidence les obstacles opérationnels et économiques à l'utilisation de véhicules électriques, qui sont liés à la technologie elle-même mais aussi à sa nouveauté.Une approche quantitative complète cette étude. Elle s’appuie sur un modèle de prédiction de parts de marché, qui quantifie la façon dont les contraintes économiques et opérationnelles évoluent avec les développements technologiques. Ces contraintes sont mesurées par deux indicateurs: l'adéquation de l'autonomie du véhicule avec son usage et les comparaisons de coûts totaux de possession (TCO). Une originalité du modèle est qu’il traite le montant des subventions à l’achat d’un véhicule électrique comme une variable endogène, qui s’adapte dynamiquement aux évolutions du marché.Afin de compenser le manque de données disponibles sur les usages des véhicules utilitaires, un modèle statistique a été développé. Ce modèle permet d’exploiter au mieux les données d'une enquête sur les véhicules utilitaires légers en France, menée par le service de la donnée et des études statistiques (SDES) du Ministère de la Transition Écologique et Solidaire / Freight transport. The needs of freight transport companies are assessed through some forty interviews conducted in four European countries and analyzed in the light of innovation diffusion theory. These interviews highlight the operational and economic obstacles to the use of electric vehicles, which are linked to the technology itself but also to its novelty.A quantitative approach completes this study. It is based on a market share prediction model, which quantifies how economic and operational constraints evolve with technological developments. These constraints are measured by two indicators: the vehicle's range adequacy given its use and total cost of ownership (TCO) comparisons. An original feature of the model is that it treats the amount of subsidies for the purchase of an electric vehicle as an endogenous variable that dynamically adapts to market developments.In order to compensate for the lack of available data on commercial vehicle uses, a statistical model has been developed. This model makes the best use of data from a survey on light commercial vehicles in France, conducted by the statistical department of the Ministry of the Environment (SDES).These analyses confirm that the development of the electric vehicle market is not certain and that it is currently extremely dependent on public support. Even in scenarios of continued financial support from public administrations, exponential market growth is unlikely. Rather, the market will grow slowly for many years to come, the time for technology to overcome its8dependence on public financial support. For example, our reference scenario forecasts a 13% market share for electric vans in 2032
36

INFLUÊNCIA DA AÇÃO DO TRÁFEGO NO CUSTO DE CONSTRUÇÃO E RESTAURAÇÃO DE PAVIMENTOS ASFÁLTICOS / THE INFLUENCE OF THE ACTION OF TRAFFIC IN THE COST OF CONSTRUCTION AND RESTORATION IN ASPHALT FLOORING

Klamt, Rodrigo André 16 December 2014 (has links)
It is known that traffic in Brazil has increased significantly in recent years due to high dependence on road transportation. In addition, commercial vehicles come to market with new settings, with more axles and greater cargo capacity; also as a function of legislation, that currently tolerates an overload of 10% per axle, when the vehicle is within the 5% of limit for the total gross weight (TGW). Consequently, there has been a considerable increase in the degradation of our road network. In this context, the present study aims to evaluate effects caused by the action of traffic in the cost of flexible pavements, focusing on aspects related to growth rate and excess load. Thus, the projection of traffic volume during a given period of time should express the current growth rates of cargo, so, the commercial vehicles; and it was also examined, if these indices are correlated with the Brazilian GDP and with the truck sales in the country. In another step, it was proposed a case study by selecting one of the toll plazas of the study to perform the sizing of the pavement by using DNIT method and mechanistic-empirical methods in order to analyze the influence of overloading in commercial vehicles in the design and in the cost of construction of the asphalt floors. For the same case study, it was performed the sizing and the calculation of the cost of paving restoration. Thus, in this study, it was concluded that the real traffic growth rate in the regions investigated are considerably above the one proposed by DNIT, which is 3.00%. The average growth rate of the study was 7.16%. The correlation between the rate of growth, the GDP and the truck sales was weak. The influence of overloading in the number N was in the order of 23.11% if compared the scenarios from the minor to the larger load. As for the DNIT method for different values of subgrade CBR (4%, 10% and 16%) the thickness of coating was the same for all loads, reaching the upper limit of the method in 12.5cm. By the mechanistic-empirical analysis, the one that showed to be more conservative was the comparison of the methods FHWA x Asphalt; with higher coating thickness (up to 16 cm) depending on fatigue and permanent deformation, while setting a higher execution cost, which increases the higher is the overload on commercial vehicles, being the maximum difference of cost depending on the cargo, in the order of R$ 158,231.00 (6.18%) per kilometer of pavement. As for the restoration, it was possible to realize that the increase in percentage of commercial vehicles and overloading in these vehicles causes a decrease in the allowable deflection and, consequently, an increase in thickness of reinforcement. It was observed a need of strengthen in all scenarios of loading for all characteristic deflections studied. The highest values of reinforcement thickness were for Dc equal to 125 (10−2mm) with 19 cm. The difference in the cost in function of the loading was R$ 51,450.00 (4.95%) per kilometer of pavement. The survey allowed obtain real parameters for subsequent interventions on existing roads; as well as to support new designs of road engineering. / Sabe-se que o tráfego no Brasil tem aumentado de forma significativa nos últimos anos devido à alta dependência do modo rodoviário. Além disso, os veículos comerciais surgem no mercado com novas configurações, com mais eixos e com maior capacidade de carga, em função também da legislação, que atualmente tolera sobrecarga por eixo de 10%, quando o veículo está dentro dos 5% de limite para o peso bruto total (PBT). Como consequência disso, tem-se um aumento considerável na degradação de nossa malha rodoviária. Neste âmbito, o presente estudo tem por objetivo avaliar efeitos provocados pela ação do tráfego no custo de pavimentos flexíveis, focando em aspectos relacionados a taxa de crescimento e excesso de carga. Assim, a projeção do volume de tráfego durante um dado período de tempo deverá exprimir os índices de crescimento atual da movimentação de cargas, portanto, dos veículos comerciais; procurou-se analisar, também, se tais índices se correlacionam com o PIB e com a venda de caminhões do país. Em outra etapa foi proposto um estudo de caso selecionando uma das praças do estudo para realizar o dimensionamento do pavimento pelo método do DNIT e por métodos empírico-mecanísticos a fim de analisar a influência da sobrecarga em veículos comerciais no dimensionamento e no custo da construção do pavimento. Para o mesmo estudo de caso foi realizado o dimensionamento e cálculo do custo de restauração do pavimento. Dessa forma, com este estudo, concluiu-se que a taxa de crescimento de tráfego real das regiões estudadas estão consideravelmente acima da proposta pelo DNIT, que é de 3,00%. A taxa de crescimento média global do estudo foi de 7,16%. A correlação entre a taxa de crescimento com o PIB e com a venda de caminhões foi fraca. A influência da sobrecarga no número N foi na ordem de 23,11% se comparados os cenários de menor para o maior carregamento. Quanto ao método do DNIT para diferentes valores de CBR de subleito (4%, 10% e 16%) a espessura de revestimento foi a mesma para todos os carregamentos, atingindo o limite superior do método em 12,5cm. Pela análise empírico-mecanística, a que se mostrou mais conservadora foi a comparação dos métodos FHWA x Asphalt Institute, com maiores valores de espessura de revestimento (até 16 cm) em função da fadiga e deformação permanente, apresentando também um maior custo de execução, o qual aumenta quanto maior a sobrecarga em veículos comerciais, sendo a diferença máxima de custo em função do carregamento na ordem de R$ 158.231,00 (6,18%) por quilômetro de pavimento. Quanto às restaurações, foi possível perceber que o aumento da porcentagem de veículos comerciais e sobrecarga nestes veículos ocasiona diminuição da deflexão admissível e, como consequência, um aumento na espessura de reforço. Verificou-se a necessidade de reforço em todos os cenários de carregamento para todas as deflexões características estudadas. Os maiores valores de espessura de reforço foram para Dc igual a 125 (10−2mm) com 19 cm. A diferença no custo em função do carregamento foi da ordem de R$ 51.450,00 (4,95%) por quilômetro de pavimento. A pesquisa permitiu obter parâmetros reais para posteriores intervenções nas rodovias existentes bem como para subsidiar novos projetos de engenharia rodoviária.
37

Avaliação do processo de compra de alto envolvimento : aplicação da escala Consumer Styles Inventory ao mercado brasileiro de veículos comerciais leves / Evaluation of the process of purchase of high involvement: application of the scale Consumer Styles Inventory to the Brazilian market of light commercial vehicles

Baldini, Ana Paula Teixeira 22 March 2017 (has links)
Submitted by Adriana Alves Rodrigues (aalves@espm.br) on 2017-11-22T12:41:30Z No. of bitstreams: 1 ANA PAULA TEIXEIRA BALDINI.pdf: 3710864 bytes, checksum: 138420c4029a61f1d93cdc63b5865011 (MD5) / Approved for entry into archive by Adriana Alves Rodrigues (aalves@espm.br) on 2017-11-22T12:42:00Z (GMT) No. of bitstreams: 1 ANA PAULA TEIXEIRA BALDINI.pdf: 3710864 bytes, checksum: 138420c4029a61f1d93cdc63b5865011 (MD5) / Approved for entry into archive by Ana Cristina Ropero (ana@espm.br) on 2017-11-22T13:00:44Z (GMT) No. of bitstreams: 1 ANA PAULA TEIXEIRA BALDINI.pdf: 3710864 bytes, checksum: 138420c4029a61f1d93cdc63b5865011 (MD5) / Made available in DSpace on 2017-11-22T13:00:53Z (GMT). No. of bitstreams: 1 ANA PAULA TEIXEIRA BALDINI.pdf: 3710864 bytes, checksum: 138420c4029a61f1d93cdc63b5865011 (MD5) Previous issue date: 2017-03-22 / Evaluate buying process from consumer behavior perspective is key to develop effective marketing strategies. Its importance grows as the involvement increases and decision process is perceived as riskier and more complex, especially in the search for information. In this scenario, this dissertation presents an involvement measurement for a specific category purchase: light commercial vehicles. The target is to present also the decision style that the consumer adopts in the buying process, through a scale that captures cognitive and emotional factors, known as Consumer Styles Inventory or CSI. It is also evaluated the importance of recommendations sources as they play an important role in this context, impacting not only the style adopted, but also the final choice. Therefore, it is presented four consumer clusters, according to the styles adopted. It was highlighted involvement and importance of recommendations source in the buying process for the four groups. These goals were achieved through a survey collected from 311 Brazilian buyers of light commercial vehicles. The results confirm the relationship between the constructs decision styles and involvement, as well identifies the most important recommendation sources on the buying process, according to the four clusters. Management implications are also presented based not only on the analysis and results from the survey but also in the experience of field interviews. Based on analysis and results, it is recommended improvements on the scale due low internal consistency of four CSI factors. Besides that, opportunities related to further exploratory studies and transversal analysis are presented as relevant for the light commercial vehicle buying process. / Avaliar o processo de compra sob a perspectiva do comportamento do consumidor é fundamental para traçar estratégias de marketing efetivas. A importância dessa compreensão cresce na medida em que aumenta o envolvimento na compra, ou seja, a decisão é percebida como mais arriscada e o processo, mais complexo, principalmente no tocante à busca de informações. Nesse sentido, essa dissertação apresenta o mensuramento do envolvimento em uma compra de categoria específica: veículos comerciais leves. Busca-se explicitar o estilo que o mesmo adota nesse processo de decisão, por meio de uma escala que captura fatores cognitivos e emocionais, conhecida como Consumer Styles Inventory, ou CSI. Sabe-se que as fontes de recomendações têm papel importante nesse processo, impactando não somente o estilo adotado, mas também a escolha final. Assim, adicionalmente associou-se os estilos do consumidor, ao envolvimento e às fontes de recomendações importantes no processo de compra. Esses objetivos foram atingidos por meio de pesquisa quantitativa com uma amostra de 311 respondentes brasileiros consumidores de veículos comerciais leves, que gerou quatro grupos distintos de consumidores. Os resultados confirmaram o relacionamento entre os construtos estilos decisórios e envolvimento, bem como identificaram as fontes de informação mais importantes no processo de compra, apresentando-os de maneira segmentada. A aplicabilidade gerencial da dissertação é discorrida, a partir da pesquisa quantitativa, bem como a partir da experiência de entrevistas presenciais. Baseando-se nas análises e resultados, sugerem-se melhorias da escala para a categoria de produto, devido a baixa consistência interna de quatro fatores do CSI. Além disso, oportunidades relacionadas a estudos exploratórios e transversais são apresentados como relevantes para o contexto de compra de veículos comerciais leves.
38

Des usages situés aux classes de situations : contribution à un outil destiné aux acteurs de la conception. : le cas des usages de véhicules utilitaires légers / From situated usages to classes of situations : contribution to a tool for the actors of the design process : the case of Light Commercial Vehicles' usages

Klein, Aurelie 20 October 2017 (has links)
La question générale de cette recherche porte sur l’identification et l’analyse de la diversité des usages de systèmes techniques complexes, les Véhicule Utilitaires Légers (VUL), réalisés par un groupe hétérogène d’utilisateurs professionnels pour contribuer à une typologie des usages. Cette dernière est destinée à servir de ressource informationnelle pour les acteurs de la conception de ces véhicules. Ce travail s’articule autour de deux orientations.■ La première orientation vise l’analyse de la diversité des usages afin d’en faire ressortir des critères structurant. Pour cela, nous proposons une unité d’analyse transverse à l’ensemble des activités : les « usages situés d’un système multi-instrumenté (SMI) ». Nous les définissons comme l’ensemble des actions de l’utilisateur dirigées vers un but et servant une activité générale et située, impliquant tout ou une partie du SMI en tant que médiateur ou objet de l’activité. Un SMI représente le sous-système d’instruments construit par l’utilisateur à partir d’un système technique complexe.Les analyses s’appuient sur deux séries d’observations (exploratoires et systématiques outillées) auprès d’une diversité d’utilisateurs. Les résultats montrent qu’il existe des dimensions plus larges que les différents pôles de l’activité instrumentée influençant la réalisation des usages. En effet, l’utilisateur entretient des interrelations complexes avec les ressources de son action ; les caractéristiques de l’activité générale que les usages permettent et les caractéristiques de la situation au sein de laquelle ils sont réalisés. Il existe ainsi différents types d’usages en fonction de la place du SMI au sein de l’usage et de l’objet de l’usage.■ La seconde orientation poursuit un travail de réduction de la diversité des usages dans une perspective de catégorisation. Créer une catégorisation induit la définition d’une unité d’analyse qui sous-tend la construction des catégories et les variables permettant leur discrimination. Pour cela, nous proposons de mobiliser une seconde unité d’analyse, les « classes de situations d’usages d’un SMI », permettant de monter en généralisation à travers l’identification de variables structurant les usages.Mais la simple construction d’une catégorisation n’est pas suffisante au regard des caractéristiques des processus de conception de l’entreprise et des différents besoins informationnels de ses acteurs. Nous proposons donc un premier travail de compréhension de ces processus, des tâches des différents acteurs qui y contribuent et de leurs besoins informationnels associés en termes d’usages des utilisateurs finaux. Pour cela, une série d’entretiens semi-directifs a été menée auprès d’acteurs de la conception : 1) dont certaines tâches impliquent la prise en compte des usages des VUL ; 2) réalisant des activités distinctes à différentes périodes et/ou processus de conception. Les résultats offrent des lignes directrices pour contribuer à l’évolution de la typologie des usages.Ces différents travaux permettent de proposer différentes pistes de développement de la typologie des usages existante dans l’entreprise. Celles-ci couvrent deux dimensions : 1) les données fournies par la typologie et leur mode de présentation ; 2) la méthode de mise à jour de ces données. / The main purpose of this research is based on identifying and analysing the usages diversity of complex technical systems, Light Commercial Vehicles (LCV), carried out by heterogeneous professional users so as to contribute to a typology of usages. The aim of the typology is to serve as an informational resource for the actors of the design process. This work revolves around two directions. ■ The first direction focuses on the analysis of the usages diversity so as to be able to put to the fore the structuring criteria. To this end, we propose a transversal analysis unit to all the activities: “the situated usages of a multi instrumented system (MIS)”. We define them as all the user’s actions directed towards a specific goal that performs a general and situated activity, and involves all or part of the MIS as a mediator or object of the activity. The MIS represents the sub-instrumental system built from a complex technical system by the user. The analyses are based on two sets of observations (exploratory and systematic ones) among a variety of users. The results show that there are wider dimensions to the several poles of the instrumented activity influencing the realization of the usages. Indeed, the user is having complex interrelations with the resources of his action and with the characteristics of the global activity allowed by the usages and the characteristics of the situation under which they are produced. Therefore there are different types of usages depending on the SMI position within the usage and the object of the usage.■ The second direction aims at a reduction of the usages diversity purpose so as to achieve of categorization. Creating a categorization implies the need to define an analysis unit that underlies the construction of categories and variables allowing their discrimination. To this end, we propose to highlight a second analysis unit, “the usages situations’ classes of a SMI”, to enable further generalization through variables that structure the usages.But the sole conception of a categorization is not sufficient enough compared to the company’s design characteristics and to the various informative needs of its actors. As a consequence we propose a first task to apprehend the understanding of the processes involved as well as the different agents’ assignments which contribute to this understanding and to the informational needs in terms of final users’ usages they may require. In order to do so, a series of semi structured interviews were held with those involved in design: 1) some tasks imply the necessity to take into account LCV usages; 2) the performing of distinct activities at various set times and/or design processes. The results offer guidelines to contribute to the evolution of the typology of usages.These various works conducted enable us to propose different ways of developing the existing typology of usages in the company. They cover two dimensions: 1) the data provided by typology itself and one’s way to present it; 2) the methodology used to update the data.
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Estudo de viabilidade técnica sobre o uso de ligas de alumínio na fabricação de eixos traseiros trativos para aplicação em veículos comerciais

Saito, Kyosuke Siqueira 15 February 2013 (has links)
Made available in DSpace on 2016-03-15T19:36:37Z (GMT). No. of bitstreams: 1 Kyosuke Siqueira Saito.pdf: 4273063 bytes, checksum: 72ef7d0c147daede5763573276e7efda (MD5) Previous issue date: 2013-02-15 / Universidade Presbiteriana Mackenzie / The development of new commercial vehicles have as one of its major goals increase the operational energetic efficiency or fuel consumption decrease. The vehicle´s mass reduction is one of the most direct ways to achieve this goal. The vehicle´s axles usually have its structure made of ferrous materials due to its high strength and low cost. Alternative materials with lower density and higher strength are continuosly researched and developed. Among these materials the aluminum compared with ferrous materials appears as an interesting alternative to replace ferrous alloys in some applications. The aluminum have its density significantly smaller than ferrous materials opening possibilities to significant mass reductions. In this study were performed an evaluation through the comparison of aluminum alloys and ferrous materials on different load conditions and were presented the replacement gains for each load situation. It was evaluated possibility to replace ferrous materials with aluminum alloys on commercial vehicles rear axle structures through finite element analysis as a step on a new product validation. The study results show that is possible to use the aluminum in commercial vehicle axles with mass reduction ranging from 1,1% to 61,0% without loss of structural properties. / O desenvolvimento de novos veículos comerciais tem como um de seus objetivos principais o aumento da eficiência energética operacional ou redução do consumo de combustível. A redução da massa dos veículos é uma das estratégias mais diretas para o alcance deste objetivo. Os eixos de veículos tradicionalmente têm sua estrutura feita de materiais ferrosos devido à sua alta resistência e baixo custo. Materiais alternativos de mais baixa densidade e alta resistência são pesquisados e desenvolvidos continuamente. Dentre esses materiais, o alumínio, comparado com materiais ferrosos tem-se mostrado uma alternativa interessante para a substituição de ligas ferrosas para algumas aplicações. O alumínio possui uma densidade muito inferior a dos ferrosos abrindo a possibilidade de ganhos significativos de massa. Neste estudo foi feito uma avaliação através da comparação entre ligas de alumínio e materiais ferrosos em diferentes condições de carregamento e apresentado os ganhos da substituição em cada condição de carregamento. Foi avaliada a possibilidade de substituir materiais ferrosos por ligas de alumínio na estrutura de eixos traseiros de veículos comerciais através de uma análise por elementos finitos como uma etapa da validação de um novo produto. Os resultados do estudo mostram que é possível usar o alumínio na estrutura de eixos de veículos comerciais com redução de massa variando de 1,1% a 61,0% sem perda de características estruturais.
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Návrh řídícího algoritmu ABS pro nákladní vozidlo / Development of ABS Control Algorithm for Heavy Commercial Vehicle

Slepánek, David January 2018 (has links)
This thesis is concerned with ABS algorithm project for commercial vehicles. In the first part the reader is introduced to the history and first usage of the anti-blocking system, its principles and main functions. There are also driving algorithms and functionality system control. The second part is dedicated to the dynamic model, programs and ADAMS Car and MATLAB Simulink interfaces. It also contains the description of the algorithm, its parameters and basic functionality assay. Simulation, program interlink, testing and tuning are also described. The concluding part deals with results and their assessment.

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