ROS open-source audio recognizer: ROAR environmental sound detection tools for robot programming

Advances in audio recognition have enabled the real-world success of a wide variety of interactive voice systems over the last two decades. More recently, these same techniques have shown promise in recognizing non-speech audio events. Sounds are ubiquitous in real-world manipulation, such as the click of a button, the crash of an object being knocked over, and the whine of activation from an electric power tool. Surprisingly, very few autonomous robots leverage audio feedback to improve their performance. Modern audio recognition techniques exist that are capable of learning and recognizing real-world sounds, but few implementations exist that are easily incorporated into modern robotic programming frameworks. This paper presents a new software library known as the ROS Open-source Audio Recognizer (ROAR). ROAR provides a complete set of end-to-end tools for online supervised learning of new audio events, feature extraction, automatic one-class Support Vector Machine model tuning, and real-time audio event detection. Through implementation on a Barrett WAM arm, we show that combining the contextual information of the manipulation action with a set of learned audio events yields significant improvements in robotic task-completion rates.     

Informations-technologie

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Informations-technologie     

Improving contact realism through event-based haptic feedback

Tapping on surfaces in a typical virtual environment feels like contact with soft foam rather than a hard object. The realism of such interactions can be dramatically improved by superimposing event-based, high-frequency transient forces over traditional position-based feedback. When scaled by impact velocity, hand-tuned pulses and decaying sinusoids produce haptic cues that resemble those experienced during real impacts. Our new method for generating appropriate transients inverts a dynamic model of the haptic device to determine the motor forces required to create prerecorded acceleration profiles at the user's fingertips. After development, the event-based haptic paradigm and the method of acceleration matching were evaluated in a carefully controlled user study. Sixteen individuals blindly tapped on nine virtual and three real samples, rating the degree to which each felt like real wood. Event-based feedback achieved significantly higher realism ratings than the traditional rendering method. The display of transient signals made virtual objects feel similar to a real sample of wood on a foam substrate, while position feedback alone received ratings similar to those of foam. This work provides an important new avenue for increasing the realism of contact in haptic interactions.     

Minimization of the Intermodulation Distortion of a Nonlinearly Amplified OFDM Signal

In the course of development of the HIPERLAN-Standard OFDM (Orthogonal Frequency Division Multiplexing) was a possible candidate for the modulation scheme.An advantage of OFDM is that it can be implemented simply and that it is suitable for the transmission of high data rates in the mobile radio channel. Furthermore, it is insensitive against disturbances caused by multipath propagation. However, the OFDM signal shows a nonconstant envelope that leads to unwanted out-of-band radiation, in case the transmitter amplifier has a nonlinear characteristic.In this paper a method for the reduction of the fluctuation of the envelope of an OFDM signal is presented. Combined with a predistortion to linearize the characteristic of the transmitter amplifier an efficient method for the reduction of the out-of-band radiation results so that OFDM could prove to be a suitable modulation scheme for future mobile telecommunication applications.     

Finger motion and contact by a second finger influence the tactile perception of electrovibration

Electrovibration holds great potential for creating vivid and realistic haptic sensations on touchscreens. Ideally, a designer should be able to control what users feel independent of the number of fingers they use, the movements they make, and how hard they press. We sought to understand the perception and physics of such interactions by determining the smallest 125 Hz electrovibration voltage that 15 participants could reliably feel when performing four different touch interactions at two normal forces. The results proved for the first time that both finger motion and contact by a second finger significantly affect what the user feels. At a given voltage, a single moving finger experiences much larger fluctuating electrovibration forces than a single stationary finger, making electrovibration much easier to feel during interactions involving finger movement. Indeed, only about 30% of participants could detect the stimulus without motion. Part of this difference comes from the fact that relative motion greatly increases the electrical impedance between a finger and the screen, as shown via detailed measurements from one individual. By contrast, threshold-level electrovibration did not significantly affect the coefficient of kinetic friction in any conditions. These findings help lay the groundwork for delivering consistent haptic feedback via electrovibration.     

Hot carrier effects in Si-SiGe HBTs

Life tests were performed at room temperature on Si-SiGe HBTs by reverse biasing the base-emitter junction under open collector conditions. The effects on the DC, the low-frequency noise, and the microwave characteristics were investigated both by the analysis of experimental data and by simulations and analytical models. The stress-induced surface damage close to the emitter perimeter was identified to be the degradation mechanism mainly responsible for the variations observed, in all the investigated parameters     

Digital audio broadcasting in the FM band based on continuous phase modulation

A method for broadcasting digital audio signals simultaneously with existing analog frequency modulation radio (88-108 MHz) in adjacent channels is presented. The digital transmission is based on continuous phase modulation (CPM) and a proper reduced-state sequence estimator. With the proposed method, the power level and the symbol rate of the transmitter signal is determined in a manner that the interference the CPM signal poses for the analog FM signal in adjacent channels remains below a level according to the radio frequency emission mask defined by international rules. Due to the multipath propagation of the transmitted signal, the transmission behavior of the radio channel is determined by high dispersion up to 85 /spl mu/s. With the selected bit rate, the receiver has to cope with a channel memory of up to 17 bits. Since Viterbi detection is not feasible due to the number of channel states, detection is performed by a reduced-state sequence estimator that is able to eliminate the complete channel interference by decision feedback. Simulation results show that the detector almost achieves the detection quality of the optimum receiver. CPM achieves data rates of up to 200 kb/s inside a 200 kHz FM channel, which is sufficient for transmission of digital compressed audio signals at compact disc quality. The encouraging results of field tests will be published in another paper.     

The advent of MEMS in space

An overview of the MEMS activity at the French Space Agency (CNES) is presented. At present, MEMS are in the introduction phase and failure analysis and quality assurance (FA/QA) activities are underway for a large variety of MEMS technologies. This paper presents the CNES roadmap and methodology developed to assess the reliability of MEMS for space applications. The presented approach focuses, in particular, on the use of advanced analytical models, test vehicles, process control monitoring test structures and simulation tools to control and validate the quality of a technology. It also discusses the FA know-how and associated techniques acquired by CNES to observe, characterize, prepare and test in controlled environment MEMS processes. Finally, case studies illustrating the CNES MEMS FA/QA strategy are presented.