Monocular navigation for long-term autonomy

We present a reliable and robust monocular navigation system for an autonomous vehicle. The proposed method is computationally efficient, needs off-the-shelf equipment only and does not require any additional infrastructure like radio beacons or GPS. Contrary to traditional localization algorithms, which use advanced mathematical methods to determine vehicle position, our method uses a more practical approach. In our case, an image-feature-based monocular vision technique determines only the heading of the vehicle while the vehicle's odometry is used to estimate the distance traveled. We present a mathematical proof and experimental evidence indicating that the localization error of a robot guided by this principle is bound. The experiments demonstrate that the method can cope with variable illumination, lighting deficiency and both short- and long-term environment changes. This makes the method especially suitable for deployment in scenarios which require long-term autonomous operation

Eventos efímeros y sus huellas en la estructura urbana: Universiada de Zagreb 1987

Organizing a mega event, even an ephemeral one, can leave many material and non-material traces in a city and a host region and can be a means of bringing to life development visions and urban policy strategy. During preparations for the event itself, numerous interventions are carried out that are directly or indirectly related to the event. Depending on the type and concept of the event itself, the interventions in the city and its region can become part of their permanent heritage, thus improving the long-term quality of life of their inhabitants. The aim of this paper is to show how a large sports event, the 1987 Zagreb Summer Universiade, contributed to the development of the city and the host region, and to the implementation of the urban policy strategy of the time. Although Zagreb has a long history of urban planning, emphasis here is placed on the spatial planning documentation of the second half of the 20th century that preceded the organization of this large sports event. This paper looks at interventions carried out during the preparatory phase of the event that were directly or indirectly related to the temporary event itself as well as at the cultural and social program related to the Universiade. It may be concluded that the 14th Summer Universiade was a significant sports and cultural event that served as an instrument for carrying out numerous projects aimed at constructing new and improving existing sports facilities, accommodation capacities and the urban renewal of the city centre. Since most of the interventions would not have been carried out in such a short period of time were it not for the Universiade, it can be said that the Universiade was a means of realizing urban development policies and renewing Zagreb. The event left a lasting legacy of elements of infrastructure, suprastructure and ecostructure that the inhabitants of the city and the region continue to use for the same purposes.La organización de un mega evento, aunque sea efímero puede dejar muchas huellas materiales e inmateriales en la ciudad y la región anfitriona, y puede servir como un medio para realizar las visiones de desarrollo y la estrategia de política urbana. En la etapa de planeación y preoperativos del evento se llevan a cabo numerosas intervenciones, directa o indirectamente relacionadas con el mismo. Dependiendo del tipo y concepto del evento, las intervenciones en la ciudad y su región pueden convertirse en un patrimonio permanente, mejorando así la calidad de vida de sus habitantes a largo plazo. El objetivo de este artículo es mostrar cómo un gran evento deportivo como el de la Universiada de Verano de Zagreb en 1987 contribuyó al desarrollo de la ciudad y la región anfitriona, y a la realización de la estrategia de política urbana de esa época. Aunque Zagreb tiene una larga historia de planificación urbana, el énfasis se coloca en la documentación de planeación de la segunda mitad del siglo XX que precedió a la organización de un gran evento deportivo. Este artículo investiga las intervenciones realizadas en el período preoperativos del evento directa o indirectamente relacionado con un evento temporal, así como los programas culturales y sociales. Se puede concluir que la Catorceava Universiada de Verano fue un evento deportivo y cultural importante que sirvió como instrumento para la ejecución de numerosos proyectos; mejorando los espacios deportivos existentes, la capacidad de alojamiento y la traza urbana del centro de la ciudad a través de remodelaciones y construcciones nuevas. Dado que la mayoría de las intervenciones no se hubieran realizado en tan poco tiempo se puede decir que la Universidad fue un medio para la ejecución de la política de desarrollo urbano y la renovación de Zagreb. Ese evento dejó en el patrimonio permanentemente diversas obras de infraestructuras, supraestructuras y ecoestructuras que los habitantes de la ciudad y la región todavía utilizan para los mismos fines

Navigation without localisation: reliable teach and repeat based on the convergence theorem

We present a novel concept for teach-and-repeat visual navigation. The proposed concept is based on a mathematical model, which indicates that in teach-and-repeat navigation scenarios, mobile robots do not need to perform explicit localisation. Rather than that, a mobile robot which repeats a previously taught path can simply `replay' the learned velocities, while using its camera information only to correct its heading relative to the intended path. To support our claim, we establish a position error model of a robot, which traverses a taught path by only correcting its heading. Then, we outline a mathematical proof which shows that this position error does not diverge over time. Based on the insights from the model, we present a simple monocular teach-and-repeat navigation method. The method is computationally efficient, it does not require camera calibration, and it can learn and autonomously traverse arbitrarily-shaped paths. In a series of experiments, we demonstrate that the method can reliably guide mobile robots in realistic indoor and outdoor conditions, and can cope with imperfect odometry, landmark deficiency, illumination variations and naturally-occurring environment changes. Furthermore, we provide the navigation system and the datasets gathered at http://www.github.com/gestom/stroll_bearnav.Comment: The paper will be presented at IROS 2018 in Madri

In the Shadow of Night: Sleeping and Dreaming and Their Technical Rôles in Shakespearian Drama

This thesis aims to demonstrate the variety of ways in which sleep and dreams are employed in Shakespeare’s dramatic canon. Using a historical perspective, the work primarily examines the functions of these motifs within the design of the plays: how they contribute to the structure and unity of the works, how they assist in delineating some of the individual characters, and how they shape the atmosphere of specific dramatic situations. This kind of analysis requires an understanding of the cultural and intellectual contexts in which the fictitious representations of these phenomena were originally written and received. For this reason, the present thesis also offers a historical and cultural background, outlining the social character of the phenomena of sleep and dreams in early modern England and the history of their employment in pre-Shakespearian literature. Where relevant, the use of these motifs in the works of Shakespeare’s contemporaries is also studied. The Introduction to the thesis summarizes the current state of knowledge of the topic and defines the present author’s approach to the research question. The first chapter discusses dream literature as a genre, its themes and development before Shakespeare’s time. The second chapter analyses the dramatic functions of a sleeping character on the stage in Shakespeare’s drama and how this image developed from the dramatist’s early plays to his later and more mature works. It examines how the motif affects the image of the character in question, but also how it influences the immediate dramatic context. A special section is devoted to the topos of dreams and its use as a characterization device. The third chapter deals with fictitious dream prophecies and their technical functions in Shakespeare’s plays. Again, the chapter follows the motif from the early stages of Shakespeare’s dramatic career to his last plays, trying to determine both its staple functions and changes in its employment. The last chapter addresses the dramatic image of the night as a time in which sleeping and dreaming – but also other typically dark enterprises – occur. A special section is devoted to Shakespeare’s use of the death-as-sleep metaphor and its dramatic implications