Mapping standard for sprint orienteering: standardized competition maps for urban, park and forest areas

Orienteering maps are one of the map products where the symbol set is standardized, no national deviations are allowed. Orienteering has developed a new form of competition which was originally held in parks or urban areas. This competition form is a very short and fast event where good media coverage is possible. The use of parks and urban areas has a significant advantage: it brings the sport into the midst of people and offers opportunities for increasing public and media awareness of orienteering. The international specification for traditional orienteering maps contains symbols for man-made features. However, the symbol set needed revision and extension in order to provide a clear and unambiguous interpretation of urban terrain required for fair competition in sprint orienteering. There are a number of reasons why the mapping of urban areas needs a modified approach compared to that used for the depiction of the 'classic' forested terrain

Race development and performance-determining factors in a mass-start cross-country skiing competition

Introduction: Although five of six Olympic events in cross-country skiing involve mass-starts, those events are sparsely examined scientifically. Therefore, in this study, we investigated speed profiles, pacing strategies, group dynamics and their performance-determining impact in a cross-country skiing mass-start competition. Methods: Continuous speed and position of 57 male skiers was measured in a six-lap, 21.8 km national mass-start competition in skating style and later followed up with an online questionnaire. Skiers ranked from 1 to 40 were split into four performance-groups: R1–10 for ranks 1 to 10, R11–20 for ranks 11 to 20, R21–30 for ranks 21 to 30, and R31–40 for ranks 31 to 40. Results: All skiers moved together in one large pack for 2.3 km, after which lower-performing skiers gradually lost the leader pack and formed small, dynamic packs. A considerable accordion effect occurred during the first half of the competition that lead to additional decelerations and accelerations and a higher risk of incidents that disadvantaged skiers at the back of the pack. Overall, 31% of the skiers reported incidents, but none were in R1–10. The overall trend was that lap speed decreased after Lap 1 for all skiers and thereafter remained nearly unchanged for R1–10, while it gradually decreased for the lower-performing groups. Skiers in R31–40, R21–30, and R11–20 lost the leader pack during Lap 3, Lap 4, and Lap 5, respectively, and more than 60% of the time-loss relative to the leader pack occurred in the uphill terrain sections. Ultimately, skiers in R1–10 sprinted for the win during the last 1.2 km, in which 2.4 s separated the top five skiers, and a photo finish differentiated first from second place. Overall, a high correlation emerged between starting position and final rank. Conclusions: Our results suggest that (a) an adequate starting position, (b) the ability to avoid incidents and disadvantages from the accordion effect, (c) tolerate fluctuations in intensity, and (d) maintain speed throughout the competition, particularly in uphill terrain, as well as (e) having well-developed final sprint abilities, are key factors determining performance during skating-style mass-start cross-country skiing competitions.publishedVersio

Oceanus.

v. 28, no. 1 (1985

Radar systems for the water resources mission, volume 1

The state of the art determination was made for radar measurement of: soil moisture, snow, standing and flowing water, lake and river ice, determination of required spacecraft radar parameters, study of synthetic-aperture radar systems to meet these parametric requirements, and study of techniques for on-board processing of the radar data. Significant new concepts developed include the following: scanning synthetic-aperture radar to achieve wide-swath coverage; single-sideband radar; and comb-filter range-sequential, range-offset SAR processing. The state of the art in radar measurement of water resources parameters is outlined. The feasibility for immediate development of a spacecraft water resources SAR was established. Numerous candidates for the on-board processor were examined

Visual attention and swarm cognition for off-road robots

Tese de doutoramento, Informática (Engenharia Informática), Universidade de Lisboa, Faculdade de Ciências, 2011Esta tese aborda o problema da modelação de atenção visual no contexto de robôs autónomos todo-o-terreno. O objectivo de utilizar mecanismos de atenção visual é o de focar a percepção nos aspectos do ambiente mais relevantes à tarefa do robô. Esta tese mostra que, na detecção de obstáculos e de trilhos, esta capacidade promove robustez e parcimónia computacional. Estas são características chave para a rapidez e eficiência dos robôs todo-o-terreno. Um dos maiores desafios na modelação de atenção visual advém da necessidade de gerir o compromisso velocidade-precisão na presença de variações de contexto ou de tarefa. Esta tese mostra que este compromisso é resolvido se o processo de atenção visual for modelado como um processo auto-organizado, cuja operação é modulada pelo módulo de selecção de acção, responsável pelo controlo do robô. Ao fechar a malha entre o processo de selecção de acção e o de percepção, o último é capaz de operar apenas onde é necessário, antecipando as acções do robô. Para fornecer atenção visual com propriedades auto-organizadas, este trabalho obtém inspiração da Natureza. Concretamente, os mecanismos responsáveis pela capacidade que as formigas guerreiras têm de procurar alimento de forma auto-organizada, são usados como metáfora na resolução da tarefa de procurar, também de forma auto-organizada, obstáculos e trilhos no campo visual do robô. A solução proposta nesta tese é a de colocar vários focos de atenção encoberta a operar como um enxame, através de interacções baseadas em feromona. Este trabalho representa a primeira realização corporizada de cognição de enxame. Este é um novo campo de investigação que procura descobrir os princípios básicos da cognição, inspeccionando as propriedades auto-organizadas da inteligência colectiva exibida pelos insectos sociais. Logo, esta tese contribui para a robótica como disciplina de engenharia e para a robótica como disciplina de modelação, capaz de suportar o estudo do comportamento adaptável.Esta tese aborda o problema da modelação de atenção visual no contexto de robôs autónomos todo-o-terreno. O objectivo de utilizar mecanismos de atenção visual é o de focar a percepção nos aspectos do ambiente mais relevantes à tarefa do robô. Esta tese mostra que, na detecção de obstáculos e de trilhos, esta capacidade promove robustez e parcimónia computacional. Estas são características chave para a rapidez e eficiência dos robôs todo-o-terreno. Um dos maiores desafios na modelação de atenção visual advém da necessidade de gerir o compromisso velocidade-precisão na presença de variações de contexto ou de tarefa. Esta tese mostra que este compromisso é resolvido se o processo de atenção visual for modelado como um processo auto-organizado, cuja operação é modulada pelo módulo de selecção de acção, responsável pelo controlo do robô. Ao fechar a malha entre o processo de selecção de acção e o de percepção, o último é capaz de operar apenas onde é necessário, antecipando as acções do robô. Para fornecer atenção visual com propriedades auto-organizadas, este trabalho obtém inspi- ração da Natureza. Concretamente, os mecanismos responsáveis pela capacidade que as formi- gas guerreiras têm de procurar alimento de forma auto-organizada, são usados como metáfora na resolução da tarefa de procurar, também de forma auto-organizada, obstáculos e trilhos no campo visual do robô. A solução proposta nesta tese é a de colocar vários focos de atenção encoberta a operar como um enxame, através de interacções baseadas em feromona. Este trabalho representa a primeira realização corporizada de cognição de enxame. Este é um novo campo de investigação que procura descobrir os princípios básicos da cognição, ins- peccionando as propriedades auto-organizadas da inteligência colectiva exibida pelos insectos sociais. Logo, esta tese contribui para a robótica como disciplina de engenharia e para a robótica como disciplina de modelação, capaz de suportar o estudo do comportamento adaptável.Fundação para a Ciência e a Tecnologia (FCT,SFRH/BD/27305/2006); Laboratory of Agent Modelling (LabMag

A low cost virtual reality interface for educational games

Mobile virtual reality has the potential to improve learning experiences by making them more immersive and engaging for students. This type of virtual reality also aims to be more cost effective by using a smartphone to drive the virtual reality experience. One issue with mobile virtual reality is that the screen (i.e. main interface) of the smartphone is occluded by the virtual reality headset. To investigate solutions to this issue, this project details the development and testing of a computer vision based controller that aims to have a cheaper per unit cost when compared to a conventional electronic controller by making use of 3D printing and the built-in camera of a smartphone. Reducing the cost per unit is useful for educational contexts as solutions would need to scale to classrooms sizes. The research question for this project is thus, “can a computer vision based virtual reality controller provide comparable immersion to a conventional electronic controller”. It was found that a computer vision based controller can provide comparable immersion, though it is more challenging to use. This challenge was found to contribute more towards engagement as it did not diminish the performance of users in terms of question scores

In the Hustle Park: The Social Organization of Disorder in a West African Travel Hub

Accra’s central bus station is a hub of travel and of turmoil. On its grounds, a great many people interact with each other in a great many ways. While this plenitude of actions and transactions is framed by an eclectic array of involutionary-evolved organizational structures, in the combined thrust of activities, confusion and unpredictability abound. For the transient traveller, the experience of the station’s turmoil translates into feelings of threat and anxiety. For those who inhabit the station, it is the very unpredictability inscribed into its space that provides opportunities and shelter. These contrastive local perceptions of the station echo the diverging academic discourses on the states of disorder that rule many spheres of everyday life in African cities, in which scenarios of unruly chaos are contrasted with visions of the self-regulating powers of social ingenuity. In this article, I explore urban disorder’s ambivalent potency as it becomes manifest, writ large, in the organization and the everyday life of a West African travel hub