Detection of Static and Mobile Targets by an Autonomous Agent with Deep Q-Learning Abilities

This paper addresses the problem of detecting multiple static and mobile targets by an autonomous mobile agent acting under uncertainty. It is assumed that the agent is able to detect targets at different distances and that the detection includes errors of the first and second types. The goal of the agent is to plan and follow a trajectory that results in the detection of the targets in a minimal time. The suggested solution implements the approach of deep Q-learning applied to maximize the cumulative information gain regarding the targets’ locations and minimize the trajectory length on the map with a predefined detection probability. The Q-learning process is based on a neural network that receives the agent location and current probability map and results in the preferred move of the agent. The presented procedure is compared with the previously developed techniques of sequential decision making, and it is demonstrated that the suggested novel algorithm strongly outperforms the existing methods.     

Linearizable Abel equations and the Gurevich–Pitaevskii problem

Applying symmetry reduction to a class of $\mathrm{SL}(2,\mathbb{R})$-invariant third-order ordinary differential equations (ODEs), we obtain Abel equations whose general solution can be parameterized by hypergeometric functions. Particular case of this construction provides a general parametric solution to the Kudashev equation, an ODE arising in the Gurevich–Pitaevskii problem, thus giving the first term of a large-time asymptotic expansion of its solution in the oscillatory (Whitham) zone.     

Recent advances in laser self-injection locking to high-Q microresonators

The stabilization and manipulation of laser frequency by means of an external cavity are nearly ubiquitously used in fundamental research and laser applications. While most of the laser light transmits through the cavity, in the presence of some back-scattered light from the cavity to the laser, the self-injection locking effect can take place, which locks the laser emission frequency to the cavity mode of similar frequency. The self-injection locking leads to dramatic reduction of laser linewidth and noise. Using this approach, a common semiconductor laser locked to an ultrahigh-Q microresonator can obtain sub-Hertz linewidth, on par with state-of-the-art fiber lasers. Therefore it paves the way to manufacture high-performance semiconductor lasers with reduced footprint and cost. Moreover, with high laser power, the optical nonlinearity of the microresonator drastically changes the laser dynamics, offering routes for simultaneous pulse and frequency comb generation in the same microresonator. Particularly, integrated photonics technology, enabling components fabricated via semiconductor CMOS process, has brought increasing and extending interest to laser manufacturing using this method. In this article, we present a comprehensive tutorial on analytical and numerical methods of laser self-injection locking, as well a review of most recent theoretical and experimental achievements.     

Integer knapsack problems with profit functions of the same value range

4OR - Integer knapsack problems with profit functions of the same value range are studied. Linear time algorithms are presented for the case of convex non-decreasing profit functions, and an...     

Diblock Copolymer Micelles with Ionic Amphiphilic Corona

Summary: Aqueous dispersions of diblock copolymer micelles with homogeneous hydrophobic core (polystyrene) and heterogeneous amphiphilic corona from ionic N-ethyl-4-vinylpyridinium bromide (EVP) and hydrophobic 4-vinylpyridine (4VP) units have been prepared at pH 9. The structure and dispersion stability of micelles as function of the ratio and distribution pattern of ionic and hydrophobic units in corona have been systematically studied by means of transmission electron microscopy, static and dynamic light scattering, UV-spectrophotometry techniques. It was shown that gradual decrease of the quantity of EVP-units in corona had no impact on micelle structure until its fraction was above 0.7. When EVP-fraction dropped below this point noticeable changes in micelle mass and dimensions were observed. In the case of random distribution of 4VP and EVP units these changes were moderate in value and jump-like in character. In the case of mictoarm (starlike) distribution of 4VP and EVP blocks changes were large in value and monotonous in character. The presented results may be of certain use for design of polymer micelles with nanosegregated corona.     

Mutual effect of the interaction of human serum albumin with cellulose in water

Adsorption of human serum albumin to microcrystalline cellulose interface has been determined as functions of protein concentration and pH of the aqueous solutions. The maximum adsorption value is reached at the protein isoelectric point. The study of adsorption at several values of pH indicates that its interaction with the MCC interface is not controlled by the electrostatic effect. The FTIR, ¹³C NMR data reveal that human serum albumin denaturates at its IEP and its macromolecules become extended. Resulting intercalates consist of microcrystalline cellulose, albumin, and solvent.     

Micromolar Affinity and Higher: Synthetic Host–Guest Complexes with High Stabilities

The design of high-affinity synthetic host–guest complexes is of paramount importance because they are key elements in constructing unprecedented supramolecular assemblies, functional materials, molecular probes, artificial signal transduction events, and interfaces with the biological world. The present review article collects recent achievements in the design of 1 : 1 host–guest complexes with outstanding stabilities, i.e., exceeding 10⁶ M⁻¹. The relationships between the measured thermodynamic constants and the structural parameters of the interacting species are analyzed. The design features of high-affinity hosts are discussed in light of their binding properties. Different solvents and different types of noncovalent interactions are considered for the stabilization of the complexes. Finally, some hints are provided for the design of future synthetic receptors displaying high affinity and selectivity.