The task of building a map of an unknown environment and concurrently using that map to navigate is a central problem in mobile robotics research. This paper addresses the problem of how to perform concurrent mapping and localization (CML) adaptively using sonar. Stochastic mapping is a feature-based approach to CML that generalizes the extended Kalman filter to incorporate vehicle localization and environmental mapping. The authors describe an implementation of stochastic mapping that uses a delayed nearest neighbor data association strategy to initialize new features into the map, match measurements to map features, and delete out-of-date features. The authors introduce a metric for adaptive sensing that is defined in terms of Fisher information and represents the sum of the areas of the error ellipses of the vehicle and feature estimates in the map. Predicted sensor readings and expected dead-reckoning errors are used to estimate the metric for each potential action of the robot, and the action that yields the lowest cost (i.e., the maximum information) is selected. This technique is demonstrated via simulations, in-air sonar experiments, and underwater sonar experiments. Results are shown for (1) adaptive control of motion and (2) adaptive control of motion and scanning. The vehicle tends to explore selectively different objects in the environment. The performance of this adaptive algorithm is shown to be superior to straight-line motion and random motion. Nomenclature F dynamic model H observation model M transformation relating the Fisher information between time steps recursively

The protein kinase catalytic core in essence comprises an extended network of interactions that link distal parts of the molecule to the active site where they facilitate phosphoryl transfer from ATP to protein substrate. This review defines key sequence and structural elements, describes what is currently known about the molecular interactions, and how they are involved in catalysis.

Carrier interactions in 2D nanostructures are of central importance not only in condensed‐matter physics but also for a wide range of optoelectronic and photonic applications. Here, new insights into the behavior of photoinduced carriers in layered platinum diselenide (PtSe2) through ultrafast time‐resolved pump–probe and nonlinear optical measurements are presented. The measurements reveal the temporal evolution of carrier relaxation, chemical potential and bandgap renormalization in PtSe2. These results imply that few‐layer PtSe2 has a semiconductor‐like carrier relaxation instead of a metal‐like one. The relaxation follows a triple‐exponential decay process and exhibits thickness‐dependent relaxation times. This occurs along with a band‐filling effect, which can be controlled based on the number of layers and may be applied in saturable absorption for generating ultrafast laser pulses. The findings may provide means to study many‐body physics in 2D materials as well as potentially leading to applications in the field of optoelectronics and ultrafast photonics.