Obstacle detection display for visually impaired:Coding of direction, distance, and height on a vibrotactile waist band

Electronic travel aids (ETAs) can potentially increase the safety and comfort of blind users by detecting and displaying obstacles outside the range of the white cane. In a series of experiments, we aim to balance the amount of information displayed and the comprehensibility of the information taking into account the risk of information overload. In Experiment 1, we investigate perception of compound signals displayed on a tactile vest while walking. The results confirm that the threat of information overload is clear and present. Tactile coding parameters that are sufficiently discriminable in isolation may not be so in compound signals and while walking and using the white cane. Horizontal tactor location is a strong coding parameter, and temporal pattern is the preferred secondary coding parameter. Vertical location is also possible as coding parameter but it requires additional tactors and makes the display hardware more complex and expensive and less user friendly. In Experiment 2, we investigate how we can off-load the tactile modality by mitigating part of the information to an auditory display. Off-loading the tactile modality through auditory presentation is possible, but this off-loading is limited and may result in a new threat of auditory overload. In addition, taxing the auditory channel may in turn interfere with other auditory cues from the environment. In Experiment 3, we off-load the tactile sense by reducing the amount of displayed information using several filter rules. The resulting design was evaluated in Experiment 4 with visually impaired users. Although they acknowledge the potential of the display, the added of the ETA as a whole also depends on its sensor and object recognition capabilities. We recommend to use not more than two coding parameters in a tactile compound message and apply filter rules to reduce the amount of obstacles to be displayed in an obstacle avoidance ETA.</p

Opsporing Verzocht

Wekelijks kijkt meer dan een miljoen mensen naar Opsporing Verzocht op televisie. Hoewel dit programma al bijna dertig jaar bestaat, past het in een trend waarin de politie steeds vaker gebruik maakt van de media om de hulp van burgers in te roepen bij de opsporing van verdachten. We spreken hier van opsporingsberichtgeving: het tonen van beelden van verdachten of het verspreiden van andere informatie over delicten met als primair doel hulp te vragen aan het publiek bij het oplossen van deze zaken. Dat roept de vraag op hoe effectief opsporingsberichtgeving is. Die vraag is mede relevant omdat het verspreiden van informatie over verdachten mogelijk verstrekkende gevolgen voor hen kan hebben. Dit onderzoek beantwoordt de vraag naar de bijdrage van Opsporing Verzocht aan de oplossing van delicten. Deze vraagstelling wordt beantwoord middels een quasi-experimenteel onderzoek. De in Opsporing Verzocht uitgezonden zaken worden in de eerste plaats vergeleken met delicten waarvan geen opsporingsbericht in Opsporing Verzocht is getoond. In de tweede plaats meten we het effect van variatie in de kijkcijfers van Opsporing Verzocht. Hiervoor maken we gebruik van de variatie in kijkcijfers die wordt veroorzaakt door het gelijktijdig uitzenden van een voetbalwedstrijd uit de Champions League. Op basis van beide onderzoeksmethoden blijkt de bijdrage van Opsporing Verzocht aan het oplossen van delicten aanzienlijk te zijn

A Tactile P300 Brain-Computer Interface

In this study, we investigated a Brain-Computer Interface (BCI) based on EEG responses to vibro-tactile stimuli around the waist. P300 BCIs based on tactile stimuli have the advantage of not taxing the visual or auditory system and of being potentially unnoticeable to other people. A tactile BCI could be especially suitable for patients whose vision or eye movements are impaired. In Experiment 1, we investigated its feasibility and the effect of the number of equally spaced tactors. Whereas a large number of tactors is expected to enhance the P300 amplitude since the target will be less frequent, it could also negatively affect the P300 since it will be difficult to identify the target when tactor density increases. Participants were asked to attend to the vibrations of a target tactor, embedded within a stream of distracters. The number of tactors was two, four or six. We demonstrated the feasibility of a tactile P300 BCI. We did not find a difference in SWLDA classification performance between the different numbers of tactors. In a second set of experiments we reduced the stimulus onset asynchrony (SOA) by shortening the on- and/or off-time of the tactors. The SOA for an optimum performance as measured in our experiments turned out to be close to conventional SOAs of visual P300 BCIs

Avolition in a patient with hypogonadism

Background and Objectives: Testosterone deficiency has been implicated in the etiology of depression although there is an ongoing debate on the nature of this association. There is a paucity of data about the psychological impact of hypogonadism in genetic disorders associated with testosterone deficiency. Methods:A 57-year-old male is described who was referred for treatment resistant depression. His history showed infertility and lowered testosterone. A selective literature review is given to clarify the patient's clinical condition. Results: Cytogenetic analysis demonstrated a Robertsonian translocation between chromosomes 13 and 14 that accounted for his infertility. The psychopathological picture did not meet the criteria for a major depressive disorder but was characterized by symptoms of apathy or avolition. These symptoms were most probably aggravated by previous long lasting treatment with antidepressants. Conclusions: Testosterone deficiency may be related to motivational deficits that should not be misunderstood for depressive illness. Apathy is probably an underestimated side effect of antidepressants

A stitch in time: Efficient computation of genomic DNA melting bubbles

Background: It is of biological interest to make genome-wide predictions of the locations of DNA melting bubbles using statistical mechanics models. Computationally, this poses the challenge that a generic search through all combinations of bubble starts and ends is quadratic. Results: An efficient algorithm is described, which shows that the time complexity of the task is O(NlogN) rather than quadratic. The algorithm exploits that bubble lengths may be limited, but without a prior assumption of a maximal bubble length. No approximations, such as windowing, have been introduced to reduce the time complexity. More than just finding the bubbles, the algorithm produces a stitch profile, which is a probabilistic graphical model of bubbles and helical regions. The algorithm applies a probability peak finding method based on a hierarchical analysis of the energy barriers in the Poland-Scheraga model. Conclusions: Exact and fast computation of genomic stitch profiles is thus feasible. Sequences of several megabases have been computed, only limited by computer memory. Possible applications are the genome-wide comparisons of bubbles with promotors, TSS, viral integration sites, and other melting-related regions.Comment: 16 pages, 10 figure

EmojiGrid: A 2D Pictorial Scale for the Assessment of Food Elicited Emotions

Research on food experience is typically challenged by the way questions are worded. We therefore developed the EmojiGrid: a graphical (language-independent) intuitive self-report tool to measure food-related valence and arousal. In a first experiment participants rated the valence and the arousing quality of 60 food images, using either the EmojiGrid or two independent visual analog scales (VAS). The valence ratings obtained with both tools strongly agree. However, the arousal ratings only agree for pleasant food items, but not for unpleasant ones. Furthermore, the results obtained with the EmojiGrid show the typical universal U-shaped relation between the mean valence and arousal that is commonly observed for a wide range of (visual, auditory, tactile, olfactory) affective stimuli, while the VAS tool yields a positive linear association between valence and arousal. We hypothesized that this disagreement reflects a lack of proper understanding of the arousal concept in the VAS condition. In a second experiment we attempted to clarify the arousal concept by asking participants to rate the valence and intensity of the taste associated with the perceived food items. After this adjustment the VAS and EmojiGrid yielded similar valence and arousal ratings (both showing the universal U-shaped relation between the valence and arousal). A comparison with the results from the first experiment showed that VAS arousal ratings strongly depended on the actual wording used, while EmojiGrid ratings were not affected by the framing of the associated question. This suggests that the EmojiGrid is largely self-explaining and intuitive. To test this hypothesis, we performed a third experiment in which participants rated food images using the EmojiGrid without an associated question, and we compared the results to those of the first two experiments. The EmojiGrid ratings obtained in all three experiments closely agree. We conclude that the EmojiGrid appears to be a valid and intuitive affective self-report tool that does not rely on written instructions and that can efficiently be used to measure food-related emotions