1,721,008 research outputs found
An image watermarking algorithm via zero assigned filter banks
No full textIn this paper a new method for digital image watermarking based on Zero Assigned Filter Banks and Embedded Zero Tree Wavelet (EZW) algorithm is presented. An image is partitioned into 128 x 128 subblocks and each block is processed in a three stage decomposition structure by a filter bank which is assigned a zero around the stop band. The coefficients to be marked are chosen according to the EZW algorithm. This method not only provides a robust watermarking scheme but may also be used as an effective compression strategy. The algorithm is tested under white Gaussian noise and against JPEG compression and it is observed to be robust even when exposed to high levels of corruption
Detection of Epilepsy Seizures and Epileptic Indicators in EEG Signals
No full textSymptoms of epilepsy, which is characterized by abnormal
brain electrical activity, can be observed on electroencephalography
(EEG) signal. This paper employs models of chaotic
measures of EEG and aims to help detection of epilepsy seizures
and diagnosis of epileptic indicators in seizure-free signals
Detection of epileptic indicators on clinical subbands of EEG
No full textSymptoms of epilepsy, which is characterized by abnormal brain electrical activity, can be observed on electroencephalography (EEG) signal. This paper employs models of chaotic measures on standard clinical subbands of EEG and aims to help detection of epilepsy seizures and diagnosis of epileptic indicators in interictal signals. copyright by EURASIP
An audio watermarking algorithm via zero assigned filter banks
No full textIn order to identify the owner and distributor of digital data, a watermarking scheme for audio files is proposed in frequency domain. The scheme satisfies the imperceptibility and persistence requirements and is robust against additive noise. It consists of a few stages of wavelet decomposition of several frames of the original signal using special zero assigned filter banks. By assigning zeros to filters on the high frequency portion of the spectrum, filter banks with frequency selective response is obtained. Text information is then inserted in the wavelet-decomposed and compressed signal. Several robustness tests are performed on male voice, female voice, and music files
Modeling the impact of interaction on pedestrian group motion
No full textMobile social robots aimed at interacting with and assisting humans in pedestrian areas need to understand the dynamics of pedestrian social interaction. In this work, we investigate the effect of interaction on pedestrian group motion by defining three motion models to represent (1) interpersonal-distance, (2) relative orientation and (3) absolute difference of velocities; and model them using a dataset of 12000+ pedestrian trajectories recorded in uncontrolled settings. Our contributions include: (i) Demonstrating that interaction has a prominent effect on the empirical distributions of the proposed joint motion attributes, where increasing levels of interaction lead to more regular behavior (ii) Developing analytic motion models of such distributions and reflect the effect of interaction on model parameters (iii) Detecting the social groups in a crowd with almost perfect accuracy utilizing the proposed models, despite the constant flow direction in the environment which causes unrelated pedestrians to move in a correlated way, and thus makes group recognition more difficult (iv) Estimating the level of intensity with considerable rates utilizing the proposed models
Intrinsic group behaviour II: On the dependence of triad spatial dynamics on social and personal features; and on the effect of social interaction on small group dynamics
Full text linkIn a follow-up to our work on the dependence of walking dyad dynamics on intrinsic properties of the group, we now analyse how these properties affect groups of three people (triads), taking also in consideration the effect of social interaction on the dynamical properties of the group. We show that there is a strong parallel between triads and dyads. Work-oriented groups are faster and walk at a larger distance between them than leisure-oriented ones, while the latter move in a less ordered way. Such differences are present also when colleagues are contrasted with friends and families; nevertheless the similarity between friend and colleague behaviour is greater than the one between family and colleague behaviour. Male triads walk faster than triads including females, males keep a larger distance than females, and same gender groups are more ordered than mixed ones. Groups including tall people walk faster, while those with elderly or children walk at a slower pace. Groups including children move in a less ordered fashion. Results concerning relation and gender are particularly strong, and we investigated whether they hold also when other properties are kept fixed. While this is clearly true for relation, patterns relating gender often resulted to be diminished. For instance, the velocity difference due to gender is reduced if we compare only triads in the colleague relation. The effects on group dynamics due to intrinsic properties are present regardless of social interaction, but socially interacting groups are found to walk in a more ordered way. This has an opposite effect on the space occupied by non-interacting dyads and triads, since loss of structure makes dyads larger, but causes triads to lose their characteristic V formation and walk in a line (i.e., occupying more space in the direction of movement but less space in the orthogonal one)
Social group behaviour of triads. Dependence on purpose and gender
Full text linkWe analysed a set of uninstructed pedestrian trajectories automatically tracked in a public area, and we asked a human coder to assess their group relationships. For those pedestrians who belong to the groups, we asked the coder to identify their apparent purpose of visit to the tracking area and apparent gender. We studied the quantitative dependence of the group dynamics on such properties in the case of triads (three people groups) and compared them to the two pedestrian group case (dyads), studied in a previous work. We found that the group velocity strongly depends on relation and gender for both triads and dyads, while the influence of these properties on spatial structure of groups is less clear in the triadic case. We discussed the relevance of these results to the modelling of pedestrian and crowd dynamics, and examined the possibility of the future works on this subject
Walk the Talk: Gestures in Mobile Interaction
No full textThis study aims at describing navigation guidelines and concerning analytic motion models for a mobile interaction robot, which moves together with a human partner. We address particularly the impact of gestures on the coupled motion of this human-robot pair. We pose that the robot needs to adjust its navigation in accordance to its gestures in a natural manner (mimicking human-human locomotion). In order to justify this suggestion, we first examine the motion patterns of real-world pedestrian dyads in accordance to 4 affective components of interaction (i.e. gestures). Three benchmark variables are derived from pedestrian trajectories and their behavior is investigated with respect to three conditions: (i) presence/absence of isolated gestures, (ii) varying number of simultaneously performed (i.e. concurring) gestures, (iii) varying size of the environment. It is observed empirically and proven quantitatively that there is a significant difference in the benchmark variables between presence and absence of the gestures, whereas no prominent variation exists in regard to the type of gesture or the number of concurring gestures. Moreover, size of the environment is shown to be a crucial factor in sustainability of the group structure. Subsequently, we propose analytic models to represent these behavioral variations and prove that our models attain significant accuracy in reflecting the distinctions. Finally, we propose an implementation scheme for integrating the analytic models to practical applications. Our results bear the potential of serving as navigation guidelines for the robot so as to provide a more natural interaction experience for the human counterpart of a robot-pedestrian group on-the-move
Gender profiling of pedestrian dyads
No full textIn traffic safety community, behavioral differences between genders
have been attracting considerable attention in recent decades. Various empirical
studies have proven that gender has a significant relation to drivers’, cyclists’ or
pedestrians’ decision making, route choice, rule compliance, as well as risk tak-
ing/perception. However, most studies examine behavior of individuals, and only
very few consider (pedestrian) groups with different gender profiles. Therefore,
this study investigates effect of gender composition of pedestrian dyads on the
tangible dynamics, which may potentially help in automatically understanding
and interpreting higher level behaviors such as decision making. We first propose
a set of variables to represent dyads’s physical/dynamical state. Observing em-
pirical distributions, we comment on the effect of gender interplay on locomotion
preferences. In order to verify our inferences quantitatively, we propose a gender
profile recognition algorithm. Removing one variable at a time, contribution of
each variable to recognition is evaluated. Our findings indicate that height related
variables have a more strict relation to gender, followed by group velocity and
inter-personal distance. Moreover, the “male” effect on dyad motion is found to
somehow diminish when the male is paired with a female
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