Master of Science

Safety concerns have been keeping autonomous vehicles off the roads for decades, although the main drivers for introducing some autonomy are to increase safety, reduce congestion, and greenhouse gas emissions. Safety is a vast topic that includes the safety of the system alone, known as string stability, and the safety of the system on public roads. This thesis provides experimental validation of the string stability of the Assume-Guarantee approach. This approach suggests that each agent models the interactions with neighbors as bounded disturbances while simultaneously self-imposing symmetric magnitude bounds. Two main controllers were tested in an indoor lab set-up: decentralized platooning and decentralized cooperative adaptive cruise controllers. First, we tested three versions of the platooning controller whose objective is to maintain a constant spacing. They differ in the assumptions and guarantees. We observed a robust performance with relaxed bounds and some violations as the bounds become tighter and tighter. Second, we modified and transformed the platoon model into cooperative adaptive cruise control (CACC). Unlike the platoon controller, the cooperative adaptive cruise controller keeps the time gap constant. Two experiments were conducted at different velocities to evaluate the limitation of the controller. The results show a stable and smooth performance.

Indiana University-Purdue University Indianapolis (IUPUI) / Autonomous vehicles currently dominate the automobile field for their impact on humanity and society. Connected and Automated Vehicles (CAV’s) are vehicles that use different communication technologies to communicate with other vehicles, infrastructure, the cloud, etc. With the information received from the sensors present, the vehicles analyze and take necessary steps for smooth, collision-free driving. This the sis talks about the cruise control system along with the intersection collision avoidance system based on Petri net models. It consists of two internal controllers for velocity and distance control, respectively, and three external ones for collision avoidance. Fault-tolerant redundant controllers are designed to keep these three controllers in check. The model is built using a PN toolbox and tested for various scenarios. The model is also validated, and its distinct properties are analyzed.

Preliminary plots are required when beginning a cruise for a timber sale in order to get an idea of how much variation in volume exists within the sale area. This variation is known as the coefficient of variation (CV) and is subsequently used to estimate the number of plots needed to implement the cruise to a desired level of accuracy (allowable error). By looking at a large number of sale inventories and finding similarities among key attributes (trees per acre, diameter at breast height and an estimate of variance), two models were derived based on simple stand observations to aid field personnel in determining a more accurate estimate of the CV. Furthermore, the models estimate the number of 1/10 acre plots needed to sample a stand to within a ± 10% allowable error at the 90% confidence level for total tonnage.

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Yes / The purpose of this study is to investigate what type of Facebook posts help cruise lines build bridging and bonding social capital. The study applies the Chi-Square Automatic Interaction Detection (CHAID) method to identify which types of posts establish bridging and bonding social capital. The analysis is conducted on an international cruise line’s official Facebook posts posted between 1 January 2018 and 1 January 2020 before the Covid-19 pandemic. The results highlight that media type, embedding passenger motivation, and a ship image help establish both bridging and bonding social capital, while content type helps establish bridging social capital. The paper is original because it helps understand how cruise lines can improve bonding and bridging social capital via social media. The paper also enhances understanding of social capital theory in the travel industry by investigating the relationship between Facebook post types and social capital in cruise shipping.

An investigation of the flow field during eject of a cruise missile from the launch tube was undertaken using a "cold" flow simulation. A facility was developed whereby various design changes in the missile ejection apparatus, denoted the vertical support assembly, could be quickly and easily assessed in terms of the relative effects on the flow field. Flow visualization techniques using fluorescent dye allowed for documentation of flow patterns in the baseline configuration, such as backflow, jetting, and recirculation regions, as well as for the location of several potential hot spots. The mixing of the fuel-rich gas generator effulent and the air in the launch tube was assessed by thermocouple measurements; warm water was used to simulate the exhaust while ambient water represented the air initially contained in the launch tube. The results have shown that air is inefficiently mixed in large portions of the vertical support assembly volume. However, strong flameholding zones are established in the region vacated by the accelerating missile, where it is believed that secondary combustion could occur. The flow field characterization has shown that considerable improvements to system performance should be possible through geometrical changes to promote more efficient mixing. / M.S.

Une trace est une suite d’empreintes, laissées par le passage d’un être ou d’un objet – c’est donc avant tout l’indice d’un chemin parcouru. C’est à ce déplacement dans le temps et dans l’espace qu’invitent mes travaux de recherche dont l’objectif est de suivre Edith Wharton « à la trace ». La trace, c’est d’abord, pour ce qu’elle nous apprend sur le voyageur et son rapport au monde, cette croisière en Méditerranée qu’elle entreprend en 1888 à bord du Vanadis. C’est également l’empreinte qui subsiste de cette expérience du voyage : un manuscrit dactylographié qui retrace le périple et rend compte du rapport particulier d’Edith Wharton à l’écriture.La trace – ce qu’on suit (« suivre à la trace ») – renvoie donc à une double activité : d’une part au voyage lui-même, d’autre part, à l’exploration de toutes les pistes que j’ai cru bon d’ouvrir à partir du document originel : sur la vie et l’œuvre d’Edith Wharton, sur son environnement socio-culturel et sur le genre de la littérature de voyage – toute une série d’empreintes, donc de signes conduisant à de nombreux signifiés. La question demeure toujours, en dernier ressort, de savoir si les signifiés que croit avoir découvert le chercheur sont bien ceux de l’écrivain. / A trace is both a material imprint and a trail or series of imprints, marking the passage of a being or an object in transit; it can therefore be understood as the material evidence of a path that has been pursued. In the particular context of this research, the term trace refers first and foremost to the record of a sea voyage. This unpublished journal, kept by Edith Wharton, gives an account of the various stages of the Mediterranean cruise she made in the yacht, the Vanadis, in the spring of 1888.This long book is of particular interest, insofar as it, not only gives a fascinating account of the response of a young nineteenth-century cultivated American to the different cultures discovered in the course of a voyage leading her from North Africa to the Greek Islands and the shores of the Adriatic, but also provides valuable insight into the early responses of an artist in the making.The term “trace” therefore refers to both these aspects: first the voyage itself, the places visited, their physical features and historical significance; secondly the traces left by the visitor who embarked on this adventure at a turning point in her life. The sentiment that the future artist is poised at the crossroads of her existence, leads the researcher – in an attempt to leave as few stones as possible unturned – on a trail leading back to her past and forward to her future. This investigation would not be complete without a survey of travel literature, as the particular genre Edith Wharton has chosen as her means of expression. All these traces unite to form a series of “signs” (in the Saussurian sense of the word), which the researcher endeavours to interpret in the hopes of understanding what is “signified” on a deeper level.

Carnival, Royal Caribbean, and Norwegian—the most profitable cruise lines today—emerged between the late 1960s and early 1970s, as the elitist leisure ocean travel industry attempted to recover from economic downturn. These mass-market lines targeted an American middle class that increasingly had the desire and financial means to travel. They secured much of this untapped market by creating packaged vacations that responded to the needs and tastes of a middle-class clientele. Drawing on cruise advertisements, newspaper articles, ephemera, industry documents, travel writing, and memorabilia books, this dissertation analyzes how these three companies used cultural and geographic referents to produce cruise vacations, responding to an increased consumer interest in cultural sampling as an accruement of economic globalization. Findings suggest that cruise ships offered their owners a space to arrange simulated interactions with global cultures—a practice that soon extended to Caribbean cruise ports as these companies gained the market power to influence encounters there. This complex collision of global cultures was advanced by a goal to offer passengers opportunities to discover new worlds. However, many of the cultural representations displayed on cruise ships were pastiches—essentializations drawn from popular media forms and based in Eurocentrism. These were meant to be entertaining, not accurate, representations. Nevertheless, as themed environments gained momentum, these cultural forms helped to transform ships into destinations in their own right—a process through which cruise lines produced a captive audience to siphon passenger spending from the Caribbean. At the same time, cruise lines leveraged their mediating power and economic influence to hide from passengers the supposed poverty, crime, and disease at Caribbean ports, and even the mundanities of daily life there, while increasingly installing mechanisms to appropriate spending from those who chose to debark the ship. These processes intensified as the decades advanced. This study thus finds that cultural homogenization did not result in an immediately apparent reduction of difference, because difference was profitable and central to the mass-market cruise industry’s advertising strategies. However, the surface-level cultural heterogeneity that cruises offered was reduced through a homogenizing vision that balanced novelty with passenger comfort, engagement, and convenience in support of corporate profits. The resulting cultural production process was not suggestive of glocalization, but rather a new phenomenon meriting further research.

Detta projekt behandlar metodutveckling för att modellera en trevägskatalysator som skulle kunna användas vidare för att uppskatta utsläppen från en Ottomotor. Modellen är byggd i AVL Cruise M för att bestämma omvandlingarna för de tre lagstiftade föroreningarna kolmonoxid, kväveoxider (NOx) och metan baserat på reaktioner som sker i trevägskatalysatorer. Projektet tar också upp olika experimentella metoder och specifika kalibreringsmetoder som används för att samla in data och bygga modellen. Projektet diskuterar två olika kalibreringsprocesser baserade på insamlade experimentella data och antalet reaktioner kalibrerade i varje steg. Dessutom diskuteras programvaran som används och ändringarna som gjorts i den fördefinierade modellen av programvaran. Resultatet efter kalibreringen visade att den andra kalibreringsprocessen gav bättre resultat, men vissa avvikelser observerades i den byggda modellen. Avvikelserna antas bero på följande tre anledningar. För det första, försummar ytreaktionsmodellen föroreningarnas diffusionshastigheter. Dessutom kan komplexiteten hos objektfunktionen som matas in i optimeraren samt de stationära data som används för kalibreringsändamål också ge avvikelser. Dessa tre argument testas i projektet och slutsatserna som dras för att kunna förbättra modellen är följande.  Objektfunktionen behöver förenklas så mycket som möjligt, diffusion av föroreningar genom washcoaten kan inkluderas i olika komplicerade steg och syrelagringsreaktioner blir viktiga när man tar hänsyn till transienta förhållanden. / This project discusses about development of a method to model the three-way catalyst which could be used further to estimate the emissions from an Otto engine. The model is built in the commercial software called AVL Cruise M to determine the conversions of three legislative pollutants namely, carbon monoxide, nitrogen oxide and methane based on reactions occurring within the three-way catalyst. The project also discusses about different experimental and calibration methods used for collecting the data and building the model. The project discusses two different calibration process based on the experimental data used and number of reactions calibrated on each step. Furthermore, the software used, and the modifications made in the predefined model of the software are also discussed. The result after the calibration showed that the second calibration process gave better results, but some deviations were observed in the model built. The deviations are assumed to be because of three arguments present. Firstly, considering the surface reaction model which neglects the diffusion rates of the species. Secondly, the complexity of the objective function fed into the optimiser. The optimiser is also a software by AVL named design explorer which helps to optimise the parameters. And thirdly, the use of steady state data only and not including transient conditions for the calibration purposes. These arguments are tested in the project, and it is concluded to improve the model, the objective function needs to be simplified as much as possible, diffusion of species through washcoat could be considered at advance stages and oxygen storage reactions become important when transient conditions are taken into consideration.