No abstract

This paper presents a different approach to tackle the Sound Source Localization (SSL) problem apply on a compact microphone array that can be mounted on top of a small moving robot in an indoor environment. Sound source localization approaches can be categorized into the three main categories; Time Difference of Arrival (TDOA), high-resolution subspace-based methods, and steered beamformer-based methods. Each method has its limitations according to the search or application requirements. Steered beamformer-based method will be used in this paper because it has proven to be robust to ambient noise and reverberation to a certain extent. The most successful and used algorithm of this method is the SRP-PHAT algorithm. The main limitation of SRP-PHAT algorithm is the computational burden resulting from the search process, this limitation comes from searching among all possible candidate locations in the searching space for the location that maximizes a certain function. The aim of this paper is to develop a computationally viable approach to find the coordinate location of a sound source with acceptable accuracy. The proposed approach comprises two stages: the first stage contracts the search space by estimating the Direction of Arrival (DoA) vector from the time difference of arrival with an addition of reasonable error coefficient around the vector to make sure that the sound source locates inside the estimated region, the second stage is to apply the SRP-PHAT algorithm to search only in this contracted region for the source location. The AV16.3 corpus was used to evaluate the proposed approach, extensive experiments have been carried out to verify the reliability of the approach. The results showed that the proposed approach was successful in obtaining good results compared to the conventional SRP-PHAT algorithm.

No abstract

No abstract

Underactuation is widely used when designing anthropomorphic hand, which involves fewer degrees of actuation than degrees of freedom. However, the similarities between coordinated joint movements and movement variances across different grasp tasks have not been suitably examined. This work suggests a systematic approach to identify the actuation strategy with the minimum number for degrees of actuation for anthropomorphic hands. This work evaluates the correlations of coordinated movements in human hands during 23 grasp tasks to suggest actuation strategies for anthropomorphic hands. Our approach proceeds as follows: first, we find the best description for each coordinated joint movement in each grasp task by using multiple linear regression; then, based on the similarities between joint movements, we classify hand joints into groups by using hierarchical cluster analysis; finally, we reduce the dimensionality of each group of joints by employing principal components analysis. The metacarpophalangeal joints and proximal interphalangeal joints have the best and most consistent description of their coordinated movements across all grasp tasks. The thumb metacarpophalangeal and abduction/adduction between the ring and little fingers exhibit relatively high independence of movement. The distal interphalangeal joints show a high degree of independent movement but not for all grasp tasks. Analysis of the results indicates that for the distal interphalangeal joints, their coordinated movements are better explained when all fingers wrap around the object. Our approach fails to provide more information for the other joints. We conclude that 19 degrees of freedom for an anthropomorphic hand can be reduced to 13 degrees of actuation distributed between six groups of joints. The number of degrees of actuation can be further reduced to six by relaxing the dimensionality reduction criteria. Other resolutions are as follows: (a) the joint coupling scheme should be joint-based rather than finger-based and (b) hand designs may need to include finger abduction/adduction movements. Keywords Anthropomorphic hand, prosthetic hand, degrees of freedom, dimensionality of hand movements, hand kinematics, degrees of actuation Date