Coverage Strategy for Target Location in Marine Environments Using Fixed-Wing UAVs

In this paper, we propose a coverage method for the search of lost target or debris on the ocean surface. The OSCAR data set is used to determine the marine currents and the differential evolution genetic filter is used to optimize the sweep direction of the lawnmower coverage and get the sweep angle for the maximum probability of containment. The position of the target is determined by a particle filter, where the particles are moved by the ocean currents and the final probabilistic distribution is obtained by fitting the particle positions to a Gaussian probability distribution. The differential evolution algorithm is then used to optimize the sweep direction that covers the highest probability of containment cells before the less probable ones. The algorithm is tested with a variety of parameters of the differential evolution algorithm and compared to other popular optimization algorithms.

Optimal Path Planning for a Team of Heterogeneous Drones to Monitor Agricultural Fields

In this work, we investigate the problem of finding the minimum coverage time of an agricultural field using a team of heterogeneous unmanned aerial vehicles (UAVs). The aerial robotic system is assumed to be heterogeneous in terms of the equipped cameras’ field of view, flight speed, and battery capacity. The coverage problem is formulated as a vehicle routing problem (VRP) [1] with two significant extensions. First, the field is converted into a graph, including nodes and edges generated based on sweep direction and the minimum length of UAVs’ footprints. Second, the underlying optimization problem accounts for aerial vehicles having different sensor footprints. A series of simulation experiments are carried out to demonstrate that the proposed strategy can yield a satisfactory monitoring performance and offer promise to be used in practice.

Multisensory perceptual interactions between higher-order temporal frequency signals

Naturally occurring signals in audition and touch can be complex and marked by temporal variations in frequency and amplitude. Auditory frequency sweep processing has been studied extensively; however, much less is known about sweep processing in touch since studies have primarily focused on the perception of simple sinusoidal vibrations. Given the extensive interactions between audition and touch in the frequency processing of pure tone signals, we reasoned that these senses might also interact in the processing of higher-order frequency representations like sweeps. In a series of psychophysical experiments, we characterized the influence of auditory distractors on the ability of participants to discriminate tactile frequency sweeps. Auditory frequency sweeps systematically biased the tactile perception of sweep direction. Importantly, auditory cues exerted little influence on tactile sweep direction perception when the sounds and vibrations occupied different absolute frequency ranges or when the sounds consisted of intensity sweeps. Thus, audition and touch interact in frequency sweep perception in a frequency- and feature-specific manner. Our results demonstrate that audio-tactile interactions are not constrained to the processing of simple sinusoids. Because higher-order frequency representations may be synthesized from simpler representations, our findings imply that multisensory interactions in the temporal frequency domain span multiple hierarchical levels in sensory processing.

Standardization of Current-Voltage Test Method for DSSC Products

The major differences between dye sensitized solar cell (DSSC) and p-n junction solar cells are spectrum absorption range, photoelectric conversion response time and standard test condition (STC). The operation principle of DSSC is using layers of organic molecules subject to lighting after excitation electronic then pass to the inorganic/organic layer of the wide energy gap nanolayer and voltage. Therefore, characterizations of DSSC are important in order to clarify how to determine its performance accurately. Such measurement requires considering the different level lighting on each very slow temporal response (hysteresis and transient) in its current-voltage (I-V) curves, which are dependent on the voltage sweep direction, even when the sweep time is the order of seconds. This paper presents a new test method for determining I-V performance of DSSC, which differs with IEC 60904-1 addressed on single and multi-junction samples. Results were applied to SEMI Doc. 5597 and released as SEMI PV57 by voting in 2014. Consequently, emerging photovoltaic device makers and buyers, or any other party interested, can thus have a common testing standard to refer to when desired.

New Performance Method of Capacity Effect from High to Low Level Lighting for DSC Device

With increasing applications in consumer electronics such as smart phones, laptops and tablet PCs, the need for pervasive computing with a requirement of lower power consumption is increasing every day. This opens the door for energy harvesting that could charge the batteries in these devices to keep them continually functioning in some useful state. There has been a lot of attention on flexible thin film solar cells, such as dye sensitized (DSC), organic and inorganic, given their low-cost and improving efficiency. Performance characterization DSC has been investigated, in order to clarify how to determine their performance accurately. Accurate characterization of DSC requires level lighting consideration on each very slow temporal response in the I-V curves of the DSC are clearly dependent on the voltage sweep direction, even when the sweep time is the order of seconds. Furthermore, the temporal response is dependent on different level lighting consideration. This analysis showed to improve accuracy, measurement should be real time removing capacitance effect with a Real-Time One-Sweep Method (RTOSM). Additionally, RTOSM will be useful to measuring cell performance more accurately and rapidly when evaluating solar cell performance.

Distributed acoustic cues for caller identity in macaque vocalization

Individual primates can be identified by the sound of their voice. Macaques have demonstrated an ability to discern conspecific identity from a harmonically structured ‘coo’ call. Voice recognition presumably requires the integrated perception of multiple acoustic features. However, it is unclear how this is achieved, given considerable variability across utterances. Specifically, the extent to which information about caller identity is distributed across multiple features remains elusive. We examined these issues by recording and analysing a large sample of calls from eight macaques. Single acoustic features, including fundamental frequency, duration and Weiner entropy, were informative but unreliable for the statistical classification of caller identity. A combination of multiple features, however, allowed for highly accurate caller identification. A regularized classifier that learned to identify callers from the modulation power spectrum of calls found that specific regions of spectral–temporal modulation were informative for caller identification. These ranges are related to acoustic features such as the call’s fundamental frequency and FM sweep direction. We further found that the low-frequency spectrotemporal modulation component contained an indexical cue of the caller body size. Thus, cues for caller identity are distributed across identifiable spectrotemporal components corresponding to laryngeal and supralaryngeal components of vocalizations, and the integration of those cues can enable highly reliable caller identification. Our results demonstrate a clear acoustic basis by which individual macaque vocalizations can be recognized.