Topological visual mapping in robotics

A key problem in robotics is the construction of a map from its environment. This map could be used in different tasks, like localization, recognition, obstacle avoidance, etc. Besides, the simultaneous location and mapping (SLAM) problem has had a lot of interest in the robotics community. This paper presents a new method for visual mapping, using topological instead of metric information. For that purpose, we propose prior image segmentation into regions in order to group the extracted invariant features in a graph so that each graph defines a single region of the image. Although others methods have been proposed for visual SLAM, our method is complete, in the sense that it makes all the process: it presents a new method for image matching; it defines a way to build the topological map; and it also defines a matching criterion for loop-closing. The matching process will take into account visual features and their structure using the graph transformation matching (GTM) algorithm, which allows us to process the matching and to remove out the outliers. Then, using this image comparison method, we propose an algorithm for constructing topological maps. During the experimentation phase, we will test the robustness of the method and its ability constructing topological maps. We have also introduced new hysteresis behavior in order to solve some problems found building the graph.     

Advancing age progressively affects obstacle avoidance skills in the elderly

The ability to adequately avoid obstacles while walking is an important skill that allows safe locomotion over uneven terrain. The high proportion of falls in the elderly that is associated to tripping over obstacles potentially illustrates an age-related deterioration of this locomotor skill. Some studies have compared young and old adults, but very little is known about the changes occurring within different age groups of elderly. In the present study, obstacle avoidance performance was studied in 25 young (20-37 years) and 99 older adults (65-88 years). The participants walked on a treadmill at a speed of 3 km/h. An obstacle was dropped 30 times in front of the left foot at various phases in the step cycle. Success rates (successful avoidance) were calculated and related to the time available between obstacle appearance and the estimated instant of foot contact with the obstacle (available response times or ARTs ranging from 200 to more than 350 ms). In addition, latencies of avoidance reactions, the choice of avoidance strategies (long or short step strategy, LSS or SSS), and three spatial parameters related to obstacle avoidance (toe distance, foot clearance, and heel distance) were determined for each participant. Compared to the young, the older adults had lower success rates, especially at short ARTs. Furthermore, they had longer reaction times, more LSS reactions, smaller toe and heel distances, and larger foot clearances. Within the group of elderly, only the 65-69 year olds were not different from young adults with respect to success rate, despite marked changes in the other parameters measured. In particular, even this younger group of elderly showed a dramatic reduction in the amount of SSS trials compared to young adults. Overall, age was a significant predictor of success rates, reaction times, and toe distances. These parameters deteriorated with advancing age. Finally, avoidance success rates at short ARTs were considerably worse in elderly participants who sustained recurrent falls in the six-month period prior to the assessment compared to those who sustained no or only one fall. An exercise program has been shown to improve avoidance success rates, especially at short ARTs, but the training effects on the determinants of success still need to be assessed.     

Emotional Responses to APO E Genotype Disclosure for Alzheimer Disease

The purpose of our study is to assess the emotional responses to disclosing APO E genotype to asymptomatic older adults at increased risk for Alzheimer disease (AD). This is a longitudinal cohort study of volunteer subjects who were aged 50 years or over, asymptomatic for (AD), had a family history of AD, passed a psychological assessment, and participated in pre- and post-test genetic counseling and three follow-up visits over 10 months. We analyzed responses by three emotional constructs: depressed, worried, and relieved. Three hundred and twenty-eight subjects were screened, 76 received their APO E genotype. When emotional responses occurred it was immediate, between baseline and the 1 month follow-up. Emotional reactions did not change significantly past 1 month. Our results suggest that for emotionally stable persons, disclosing results of their APO E genotype, high risk subjects did not report more depression or worry and low risk subjects felt relieved by knowing the results. Future studies should evaluate the risks of disclosure to family members involved in the diagnostic work-up of a relative and include subjects from a broader range of emotional stability and socioeconomic background.     

Pastoral counseling among Chinese churches: a Canadian study

This article reports the results of a survey of Canadian Chinese pastors (N 20) regarding their experiences and attitudes related to pastoral counseling. It identifies common concerns encountered during pastoral counseling, as well as key areas of church concerns. Results of the survey indicate that pastoral counseling may be more important than is currently recognized by Chinese pastors, particularly in key areas of marriage, family life, and general relationship issues. The authors discuss possible implications of the survey relative to training and equipping Chinese pastors to engage more in pastoral counseling as an integral part of their parish ministry.     

Direct and Nondirect Communication of Maternal Beliefs to Adolescents: Adolescent Motivations for Premarital Sexual Activity1

Communication between mothers and adolescents about premarital sexual intercourse was studied in the context of a model of maternal influence on the formation of adolescent beliefs about sexual behavior. Two different forms of maternal influence were explored: (a) direct communication, and (b) indirect transmission of maternal orientations. Respondents were 751 inner-city, African American adolescents (ages 14 to 17) and their mothers. Results indicated that adolescent motivations were related to their sexual behavior, and that maternal beliefs about sex were predictive of those motivations, independent of reports of the amount of communication that had taken place. These data are consistent with a model that underscores multiple mechanisms by which parents influence adolescent sexual behavior over and above direct communication.     

Detecting phonemes and letters in text: Interactions between different types and levels of processes

In six experiments, subjects detected phonemes or letters in text presented auditorily or visually. Experiments 1 and 2 provided support for the hypothesis that a mismatch between the phoneme and letter representations of a target leads to detection errors. In addition, visual word unitization processes were implicated. Experiments 3 and 4 provided support for the hypothesis that the Gestalt goodness of pattern affected detection errors when subjects searched for letters. Experiments 5 and 6 demonstrated that the effects of unitization on the detection of letters in common words were decreased by altering the familiar configuration of the test words. The combined results of all six experiments lead to the conclusion that both visual and phonetic processes influence letter detection, that these processes communicate through a type of cross-checking, and that there are at least two levels of visual (and perhaps of phonetic) processing involved in the letter detection task.     

Seeking harmony in Chinese families: A dyadic analysis on Chinese parent‒child relations

Based on Leung, Koch, and Lu’s (2002) dualistic harmony model, we examined the relations of two harmony‐seeking behaviors—harmony enhancement and disintegration avoidance—to family functioning among 177 Hong Kong Chinese adolescent?parent dyads. Structural equation modeling results showed that adolescent‐rated harmony enhancement was positively related to adolescent‐rated family functioning whereas parent‐rated harmony enhancement was positively related to parent‐rated family functioning. Disintegration avoidance, however, was not related to family functioning in the two samples. Furthermore, no significant cross‐path association between harmony‐seeking behaviors and family functioning was identified, meaning that the harmony‐seeking behaviors of adolescents and their parents did not relate to each other’s perception of family functioning. Implications of these findings to our understanding of family in Chinese culture are discussed.     

On the definition of differential reinforcement of alternative behavior

Differential reinforcement of alternative behavior (DRA) has a long history as a behavioral treatment. The term has usually been defined in a manner that suggests one form of behavior (usually some appropriate alternative) is reinforced, while another form of behavior (usually problem behavior) is placed on extinction. In this paper, we will suggest that DRA should not require extinction, either procedurally or by definition. Ideally, problem behavior would be placed on extinction when possible; however, when problem behavior is not or cannot be placed on extinction, the procedure used is still DRA. Thus, we propose the following definition: Providing greater reinforcement, along at least one dimension, contingent on the occurrence of one form or type of behavior, while minimizing reinforcement for another form or type of behavior.