Embora a estimação de distância tenha sido extensivamente estudada, a habilidade de humanos julgarem distâncias maiores do que 30 m tem sido pouco investigada. O objetivo deste trabalho foi avaliar o desempenho de voluntários em tarefas envolvendo o julgamento de distância e de orientação espacial pelo indicativo de resposta do caminhar com a visão ocluída em distâncias de 30,00; 41,60; 57,69 e 80,00 metros, em um ambiente amplo e natural. Para tanto, trinta e cinco voluntários de ambos os sexos, com idades ente 18 e 35 anos foram divididos aleatoriamente em três tarefas experimentais. A primeira tarefa consistiu em caminhar diretamente a um alvo, com a visão ocluída, após vê-lo brevemente. A segunda tarefa consistiu em caminhar vidente até um alvo, e subsequentemente realizar um giro de 180º e retornar sozinho, com a visão ocluída, à origem do percurso. A terceira tarefa foi similar à segunda, mas com uma diferença, o participante caminhou por distâncias com a visão ocluída, pelo guiar de um condutor, e ao final da caminhada subsequentemente, girou e retornou sozinho à origem do percurso. Em todas as tarefas experimentais, a distância caminhada (em metros) e o tempo (em segundos) de cada trajetória na fase de resposta, foram coletados e registrados utilizando um receptor de Sistema de Posição Global (GPS). Após a medição do movimento, os dados extraídos do GPS foram pós-processados e as coordenadas de todas as grandezas físicas de cada sujeito foram calculadas, a saber, a distância percorrida (metros), a velocidade (metros por segundo), o desvio angular (graus), e para o caso da trajetória circular, a velocidade angular média (radianos por segundo) e o raio da trajetória circular teórica (metros). Independente da tarefa, a observação das trajetórias produzidas pelos participantes demonstrou que os desvios de direção apresentavam padrões geométricos bem definidos (reta, circular, reta-circular, reta-reta e alternada), e os padrões reta e circular foram os mais frequentes. Em todas as tarefas, a análise das distâncias caminhadas mostrou uma tendência à subconstância perceptiva por conta do valor do expoente psicofísico abaixo de 1,0. Entretanto, esta tendência foi mais acentuada na resposta de retornar a um ponto de origem após deslocamento com os participantes sob completa privação visual sem prévisualização do alvo. Nossos resultados sugerem que os padrões das trajetórias e a acurácia das distâncias produzidas dependem da amplitude da distância, do ambiente experimental onde as distâncias foram estimadas e da disponibilidade de indícios perceptuais presentes na tarefa experimental. / Although distance estimation has been extensively studied, the human ability to judge distances greater than 30.00 m has been understudied. The objective of this work was to evaluate and analyze the performance of volunteers in tasks involving the judgment of distance and spatial orientation by the response of walking with occluded vision 30.00, 41.60, 57.69 and 80.00-meter distances. For this purpose, thirty-five volunteers of both genders, aged between 18 and 35 years were invited to participate in three experimental tasks in a natural and open field. For this purpose, thirty-five volunteers aged between 18 and 35 years of both genders were invited to participate in three experimental tasks in a natural and open field. The first task consisted of walking blindfolded directly towards a target, after seeing it briefly. The second task consisted in sighted walking until the target, and after that he or she rotated 180º and returned alone with the blinded vision to the origin of the trajectory. Finally the third task was similar to the second, but with the difference that the subject walked with the occluded vision in a straight lines distances, led by the experimenter, and subsequently, to turn and returning to the origin of the route alone. In all experimental tasks, the walked distance (in meters) and the time (in seconds) of each trajectory over the distance phase were collected and registered using a Global System Position receiver (GPS). After the measurement of the movement, the data obtained from the GPS were processed, the coordinators of the movement were determined, and the physical quantities of each subject were calculated, namely the walked distance (meters), the velocity (meters per seconds), the angular deviance (degrees), and only for the circular trajectory, the mean angular velocity (radians per seconds) and the mean radius of the theoretical circular trajectory (meters). The observation of the trajectories demonstrated that the direction deviances showed well-defined geometrical patterns (straight, circular, straight-circular, straight-straight and alternate), and the straight and circular patterns were the most frequent ones. Our results suggest that both trajectory patterns and the accuracy of the participants walked distances depend on the amplitude of the distance, the experimental environment in which distances were estimated, and the availability of perceptual evidence of distance present in the experimental task.

Embora a estimação de distância tenha sido extensivamente estudada, a habilidade de humanos julgarem distâncias maiores do que 30 m tem sido pouco investigada. O objetivo deste trabalho foi avaliar o desempenho de voluntários em tarefas envolvendo o julgamento de distância e de orientação espacial pelo indicativo de resposta do caminhar com a visão ocluída em distâncias de 30,00; 41,60; 57,69 e 80,00 metros, em um ambiente amplo e natural. Para tanto, trinta e cinco voluntários de ambos os sexos, com idades ente 18 e 35 anos foram divididos aleatoriamente em três tarefas experimentais. A primeira tarefa consistiu em caminhar diretamente a um alvo, com a visão ocluída, após vê-lo brevemente. A segunda tarefa consistiu em caminhar vidente até um alvo, e subsequentemente realizar um giro de 180º e retornar sozinho, com a visão ocluída, à origem do percurso. A terceira tarefa foi similar à segunda, mas com uma diferença, o participante caminhou por distâncias com a visão ocluída, pelo guiar de um condutor, e ao final da caminhada subsequentemente, girou e retornou sozinho à origem do percurso. Em todas as tarefas experimentais, a distância caminhada (em metros) e o tempo (em segundos) de cada trajetória na fase de resposta, foram coletados e registrados utilizando um receptor de Sistema de Posição Global (GPS). Após a medição do movimento, os dados extraídos do GPS foram pós-processados e as coordenadas de todas as grandezas físicas de cada sujeito foram calculadas, a saber, a distância percorrida (metros), a velocidade (metros por segundo), o desvio angular (graus), e para o caso da trajetória circular, a velocidade angular média (radianos por segundo) e o raio da trajetória circular teórica (metros). Independente da tarefa, a observação das trajetórias produzidas pelos participantes demonstrou que os desvios de direção apresentavam padrões geométricos bem definidos (reta, circular, reta-circular, reta-reta e alternada), e os padrões reta e circular foram os mais frequentes. Em todas as tarefas, a análise das distâncias caminhadas mostrou uma tendência à subconstância perceptiva por conta do valor do expoente psicofísico abaixo de 1,0. Entretanto, esta tendência foi mais acentuada na resposta de retornar a um ponto de origem após deslocamento com os participantes sob completa privação visual sem prévisualização do alvo. Nossos resultados sugerem que os padrões das trajetórias e a acurácia das distâncias produzidas dependem da amplitude da distância, do ambiente experimental onde as distâncias foram estimadas e da disponibilidade de indícios perceptuais presentes na tarefa experimental. / Although distance estimation has been extensively studied, the human ability to judge distances greater than 30.00 m has been understudied. The objective of this work was to evaluate and analyze the performance of volunteers in tasks involving the judgment of distance and spatial orientation by the response of walking with occluded vision 30.00, 41.60, 57.69 and 80.00-meter distances. For this purpose, thirty-five volunteers of both genders, aged between 18 and 35 years were invited to participate in three experimental tasks in a natural and open field. For this purpose, thirty-five volunteers aged between 18 and 35 years of both genders were invited to participate in three experimental tasks in a natural and open field. The first task consisted of walking blindfolded directly towards a target, after seeing it briefly. The second task consisted in sighted walking until the target, and after that he or she rotated 180º and returned alone with the blinded vision to the origin of the trajectory. Finally the third task was similar to the second, but with the difference that the subject walked with the occluded vision in a straight lines distances, led by the experimenter, and subsequently, to turn and returning to the origin of the route alone. In all experimental tasks, the walked distance (in meters) and the time (in seconds) of each trajectory over the distance phase were collected and registered using a Global System Position receiver (GPS). After the measurement of the movement, the data obtained from the GPS were processed, the coordinators of the movement were determined, and the physical quantities of each subject were calculated, namely the walked distance (meters), the velocity (meters per seconds), the angular deviance (degrees), and only for the circular trajectory, the mean angular velocity (radians per seconds) and the mean radius of the theoretical circular trajectory (meters). The observation of the trajectories demonstrated that the direction deviances showed well-defined geometrical patterns (straight, circular, straight-circular, straight-straight and alternate), and the straight and circular patterns were the most frequent ones. Our results suggest that both trajectory patterns and the accuracy of the participants walked distances depend on the amplitude of the distance, the experimental environment in which distances were estimated, and the availability of perceptual evidence of distance present in the experimental task.

Orientador: Eliane Mauerberg de Castro / Banca: Nilton Pinto Ribeiro Filho / Banca: Ricardo Kamizaki / Resumo: A percepção do espaço depende da integração das informações sensório-motoras sendo que, durante o processo de envelhecimento, essas informações podem ser alteradas, tanto em acurácia como em otimização e, então, afetar o comportamento motor. A proposta deste estudo foi verificar o status da percepção da distância egocêntrica em indivíduos idosos, usando o método experimental de triangulação. Ainda, verificar se indivíduos idosos fisicamente ativos podem ou não ter uma melhor performance do que seus pares sedentários em duas tarefas de percepção de distância. A tarefa de percepção da distância egocêntrica incluiu: 1. Apontar para os alvos continuamente enquanto caminha em uma linha reta com os olhos vendados (i.e. quatro caminhos andando com distâncias variadas foram testados) com os olhos vendados, até o final da trajetória. 2. Julgamento verbal da distância real para os alvos. Em geral, os resultados mostraram uma tendência em superestimar as distâncias curtas (i.e., 8 e 13 metros) e uma tendência em subestimar as distâncias mais longas (i.e., 20 e 30 metros). Ambos os grupos, ativos e sedentários, exibiram uma alta variabilidade na tarefa de apontar, e isso pode ser explicado pelas mudanças individuais do sistema de orientação espacial causado pelo envelhecimento. Ainda, a amplitude de movimento do braço poderia explicar o apontar não acurado para alguns alvos colocados no final do caminho percorrido. O método de triangulação não foi sensível para medir a percepção espacial destes participantes. O julgamento verbal da distância em ambos os grupos, foram igualmente acurados / Abstract: Because spatial orientation relies on integration of sensory-motor information, aging process can affect accuracy and optimization and, therefore, affect motor behavior. The purpose of this study was to verify the status of egocentric distance perception in older individuals using the triangulation experimental method. Also, to verify whether or not physically active older individuals can perform better than their sedentary peers in two egocentric distance perception tasks. The egocentric distance perception tasks included 1. pointing to targets while walking in a straight line with eyes closed (i.e., four walking paths with varied distances were tested), and 2. verbally expressing the actual distances to targets. Overall, results showed an overestimation tendency for short distances (i.e., 8 and 13 meters), and an underestimation tendency for longer distances (i.e., 20 and 30 meters). Both groups, active and sedentary, exhibited a high variability in all of the pointing task conditions. In the verbal egocentric distance perception, participants were more accurate than during the pointing task. The high variability of the pointing task can be explained by changes in individualsþ spatial orientation system caused by aging. Also, limited range of motion of the arm could explain poor pointing to some targets placed at the end of the walking pathway. The triangulation method was not sensitive to measure these participants spatial perception. The verbal judgments of distances in both groups were equally accurate / Mestre

This dissertation research separates out the social relations implied in identity theory and empirically shows the interaction of identity and social relations. I conducted 60 interviews and one online survey with respondents at two public universities in two cities with distinctive sociocultural characteristics. The respondents were graduate students from mainland China pursuing their master’s or doctoral degrees in the U.S. The students’ lengths of stay in the U.S. varied, but all experienced a major life transition from China to the U.S. The qualitative interview data show that the adoption of a religious identity in the two places, defined as different social environments, impact the interaction of identity and networks. Where the community is small and homogeneous, the Chinese graduate students are quickly thrown into strong religious dyadic relationships and primary groups, and soon thereafter acquire a religious identity. Where the community is large and sparsely connected, the identity pool is large and the adoption of the religious identity becomes less constrained by dyadic relationships and primary groups. The interview data also show that within-person time spanning (the time span between prior to the respondents’ arrival in the U.S. and after the respondents’ coming to the U.S.), and between-person time spanning (the “newcomers” who have lived in the U.S. for less than one year versus the “old-timers” who have lived in the U.S. for over one year) are important in the identity network process. The transfer from China to the U.S. fosters the emergence of the Chinese ethnic identity. The Chinese network composition of the newcomers and the old-timers granted them a similar list of important identities. The quantitative findings confirm that place, time, and personal network function together to impact identity importance. Also, the classification of ties into “important people” and “time bound people” are effective predictors of identity importance. In conclusion, this dissertation research demonstrates empirically how social relations and identity impact each other. This research also provides a case study for the population – Chinese graduate students in the U.S.

The 2011 Saskatchewan Election saw a landslide victory for The Saskatchewan Party. They also achieved this victory during a time in which the province was experiencing economic revitalization. Past studies have suggested that incumbents are rewarded for good economic times. As such, the 2011 Saskatchewan election provides for a good case study that aims to understand if perceptions of the economy influenced Saskatchewan residents vote choice at that time. Using data collected from the 2011 Saskatchewan Election Study, this thesis has found that retrospective sociotropic and egocentric perceptions of the economy did have a small direct role in influencing vote choice during the election. However, this thesis also found that once leadership opinions of Brad Wall were added to the statistical analysis these perceptions became insignificant. Interestingly, the same economic perceptions were found to make up a part of Wall’s leadership evaluation. With leadership evaluations being the largest determinant of vote choice, this thesis found that economic perceptions did play a role in the 2011 Saskatchewan Election, albeit in a roundabout way.

In this thesis, I study the computational advantages of the allocentric represen- tation as compared to the egocentric representation for autonomous local navigation. Whereas in the allocentric framework, all variables of interest are represented with respect to a coordinate frame attached to an object in the scene, in the egocentric one, they are always represented with respect to the robot frame at each time step. In contrast with well-known results in the Simultaneous Localization and Mapping literature, I show that the amounts of nonlinearity of these two representations, where poses are elements of Lie-group manifolds, do not affect the accuracy of Gaussian- based filtering methods for perception at both the feature level and the object level. Furthermore, although these two representations are equivalent at the object level, the allocentric filtering framework is better than the egocentric one at the feature level due to its advantages in the marginalization process. Moreover, I show that the object- centric perspective, inspired by the allocentric representation, enables novel linear- time filtering algorithms, which significantly outperform state-of-the-art feature-based filtering methods with a small trade-off in accuracy due to a low-rank approximation. Finally, I show that the allocentric representation is also better than the egocentric representation in Model Predictive Control for local trajectory planning and obstacle avoidance tasks.

Considerable research has examined strategies involved in spatial navigation, and what factors determine which strategy an individual will use. The little research that has examined strategy adoption has produced conflicting results. The present study investigated the relative rate of adoption of allocentric and egocentric strategies in an environment that allowed individuals to adopt one or the other, or switch between them. Results indicated that by the end of testing nearly all participants had adopted one strategy or the other. Also, more participants were using an allocentric strategy than an egocentric strategy. However, strategy selection was not related to gender, or the relative efficiency of the two strategies. Analysis of gaze position at the start of trials showed that those who adopted an allocentric strategy tended to focus their attention on the distal (landscape) features of the environment whereas those who adopted an egocentric strategy tended to focus their attention on the proximal object features. However, vertical gaze position could not be used to reveal the rate of adoption of an egocentric strategy, because this did not vary over trials. Analysis of gaze position using “regions of interest” overcame this problem and showed that both strategies are adopted at a similar rate early in trials. Comparison of strategy by gaze position and strategy by navigation probe indicated that these two metrics were measuring two different stages of navigation. Finally, analysis of the navigational efficiency of different strategies indicated that the best navigators were those who used both strategies. These findings indicate allocentric and egocentric strategies are adopted at a similar rate and that within the space of a few seconds, individuals may use different strategies for orientation and navigation. / Graduate

The research program described in this dissertation updates the knowledge base concerning human navigation and presents new methods for investigating selection and use of cognitive navigational strategies. Four experiments were designed to answer questions about the effects of environmental and experiential factors on cognitive mapping and selection of navigation strategies. Humans are thought to navigate using two different reference frames often referred to as “world based” and “person based”. These reference frames correspond to two probable cognitive/memory systems respectively labelled “allocentric” for the formation and use of cognitive maps of the environment, and “egocentric” for navigation by stimulus response or guidance. Different navigational strategies are associated with the two systems. Allocentric strategies rely on the presence of a stable environmental structure containing a number of more distal, relational stimuli whereas egocentric strategies rely only on the presence of simple, local cues (cue-based egocentric) or on body movements (response-based egocentric). The experiments tested navigation behaviour and strategy selection using virtual environment analogues of an animal model, the Morris water maze. Adaptations included, 1) the Place maze biasing participants toward the use of an allocentric strategy, 2) the Cue maze (and Floor Cue maze) biasing participants toward the use of an egocentric strategy, and 3) the Dual-strategy maze that has no bias because participants can choose to utilize either an allocentric or egocentric strategy. Experiment 1 was a behavioural study testing 101 university students in the Place maze and Floor Cue maze, with and without the opportunity to explore the environment before testing. The experiment showed for the first time that exploration is necessary for allocentric but not for egocentric navigation, suggesting that prior exploration is important for cognitive mapping. Experiment 2 outlined a novel and reliable eye tracking method for differentiating strategy use in the Place and Cue mazes. Eye movements were measured during the first orientation second of behavioural trials to differentiate allocentric from egocentric strategy use. Experiment 3 employed the established eye tracking method to test the effects of experience on strategy selection. Participants were trained in either the Place maze or the Cue maze and then tested in the Dual-strategy maze. A strategy probe trial was introduced at the end of testing to indicate whether participants had selected an allocentric or an egocentric strategy. Training experience had a strong behavioural effect on later strategy selection at the end of testing. Furthermore the effect of experience occurred independently of the gender of participants. However, the experience effect was only briefly shown using eye tracking measures. Experiment 4 was a successful feasibility study showing that eye tracking measures can be utilized to measure navigational strategy use in survivors of traumatic brain injury. Together these experiments may indicate that strategies are not innate or within the person but rather are interactions of the person with the environment. / Graduate

Made available in DSpace on 2014-06-11T19:22:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-04-10Bitstream added on 2014-06-13T20:29:14Z : No. of bitstreams: 1 cavicchia_mc_me_rcla.pdf: 485720 bytes, checksum: c910b38b7806cbea37a47eb57d7a5468 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A percepção do espaço depende da integração das informações sensório-motoras sendo que, durante o processo de envelhecimento, essas informações podem ser alteradas, tanto em acurácia como em otimização e, então, afetar o comportamento motor. A proposta deste estudo foi verificar o status da percepção da distância egocêntrica em indivíduos idosos, usando o método experimental de triangulação. Ainda, verificar se indivíduos idosos fisicamente ativos podem ou não ter uma melhor performance do que seus pares sedentários em duas tarefas de percepção de distância. A tarefa de percepção da distância egocêntrica incluiu: 1. Apontar para os alvos continuamente enquanto caminha em uma linha reta com os olhos vendados (i.e. quatro caminhos andando com distâncias variadas foram testados) com os olhos vendados, até o final da trajetória. 2. Julgamento verbal da distância real para os alvos. Em geral, os resultados mostraram uma tendência em superestimar as distâncias curtas (i.e., 8 e 13 metros) e uma tendência em subestimar as distâncias mais longas (i.e., 20 e 30 metros). Ambos os grupos, ativos e sedentários, exibiram uma alta variabilidade na tarefa de apontar, e isso pode ser explicado pelas mudanças individuais do sistema de orientação espacial causado pelo envelhecimento. Ainda, a amplitude de movimento do braço poderia explicar o apontar não acurado para alguns alvos colocados no final do caminho percorrido. O método de triangulação não foi sensível para medir a percepção espacial destes participantes. O julgamento verbal da distância em ambos os grupos, foram igualmente acurados. / Because spatial orientation relies on integration of sensory-motor information, aging process can affect accuracy and optimization and, therefore, affect motor behavior. The purpose of this study was to verify the status of egocentric distance perception in older individuals using the triangulation experimental method. Also, to verify whether or not physically active older individuals can perform better than their sedentary peers in two egocentric distance perception tasks. The egocentric distance perception tasks included 1. pointing to targets while walking in a straight line with eyes closed (i.e., four walking paths with varied distances were tested), and 2. verbally expressing the actual distances to targets. Overall, results showed an overestimation tendency for short distances (i.e., 8 and 13 meters), and an underestimation tendency for longer distances (i.e., 20 and 30 meters). Both groups, active and sedentary, exhibited a high variability in all of the pointing task conditions. In the verbal egocentric distance perception, participants were more accurate than during the pointing task. The high variability of the pointing task can be explained by changes in individualsþ spatial orientation system caused by aging. Also, limited range of motion of the arm could explain poor pointing to some targets placed at the end of the walking pathway. The triangulation method was not sensitive to measure these participants spatial perception. The verbal judgments of distances in both groups were equally accurate.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22778号 / 工博第4777号 / 新制||工||1747(附属図書館) / 京都大学大学院工学研究科電気工学専攻 / (主査)教授 中村 裕一, 教授 小山田 耕二, 教授 西野 恒 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM