TreeDQN: Learning to minimize Branch-and-Bound tree

Combinatorial optimization problems require an exhaustive search to find the optimal solution. A convenient approach to solving combinatorial optimization tasks in the form of Mixed Integer Linear Programs is Branch-and-Bound. Branch-and-Bound solver splits a task into two parts dividing the domain of an integer variable, then it solves them recursively, producing a tree of nested sub-tasks. The efficiency of the solver depends on the branchning heuristic used to select a variable for splitting. In the present work, we propose a reinforcement learning method that can efficiently learn the branching heuristic. We view the variable selection task as a tree Markov Decision Process, prove that the Bellman operator adapted for the tree Markov Decision Process is contracting in mean, and propose a modified learning objective for the reinforcement learning agent. Our agent requires less training data and produces smaller trees compared to previous reinforcement learning methods.Comment: Submitted to NeurIPS 202

INDUSTRIAL FORESTS GROWTH ON CHESTNUT SOILS OF DRY STEPPE ZONE ON THE EUROPEAN TERRITORY OF RUSSIA

Authors present materials on assessment of growth and the current state of massive petiolate oak trees in dry steppe, their dependence on the soil and climate, silvicultural factors. The ways of increasing their durability and drainage efficiency are offered

Nonlinear magnetoinductive waves and domain walls in composite metamaterials

We describe novel physics of nonlinear magnetoinductive waves in left-handed composite metamaterials. We derive the coupled equations for describing the propagation of magnetoinductive waves, and show that in the nonlinear regime the magnetic response of a metamaterial may become bistable. We analyze modulational instability of different nonlinear states, and also demonstrate that nonlinear metamaterials may support the propagation of domain walls (kinks) connecting the regions with the positive and negative magnetization.Comment: 5 pages, 5 figure

Factor VII activating protease (FSAP) influences vascular remodeling in the mouse hind limb ischemia model

Background: Investigations in factor VII activating protease (FSAP)-/- mice suggest a role for FSAP in stroke, thrombosis and neointima formation. Here, we analyzed the role of FSAP in vascular remodeling processes related to arteriogenesis and angiogenesis in the mouse hind limb ischemia model. Methods and results: Femoral artery ligation was performed in mice and exogenous FSAP was injected locally to examine its effect on arteriogenesis in the adductor and angiogenesis in the gastrocnemius muscle over 21 days. Perfusion was decreased by FSAP, which was reflected in a lower arterial diameter and was associated with reduced monocyte infiltration in the adductor muscle. There was increased angiogenesis in the gastrocnemius muscle triggered indirectly by less blood supply to the lower limb. Comparison of wild-type (WT) and FSAP-/- mice showed that perfusion was not different between the genotypes but there were 2.5-fold more collateral arteries in the adductor muscle of FSAP-/- mice at day 21. This was associated with a higher infiltration of monocytes at day 3. Capillary density in the gastrocnemius muscle was not altered. Activity of the two major proteolytic pathways associated with vascular remodeling; matrix metalloprotease (MMP)-9 and urokinase-type plasminogen activator (uPA) was elevated in the gastrocnemius but not in the adductor muscle in FSAP-/- mice. Conclusions: Arteriogenesis is enhanced, and this is associated with a higher infiltration of monocytes, in the absence of endogenous FSAP but angiogenesis is unchanged. Exogenous FSAP had the opposite effect on arteriogenesis indicating a possible therapeutic potential of modulating endogenous FSAP

Rheological properties of wheat dough with the addition of green buckwheat flour

Bread is the most affordable products in the world. In addition, bread and bakery products have high indicators of nutritional and biological value. The most important direction in this sphere, according to experts, is the enrichment of bakery products with proteins, essential amino acids, and various macro- and micronutrients. At the same time, it is important that the final product has high quality, attractive consumer properties and can be effectively sold in retail chains. Rheological studies make it possible to judge the characteristics, quality and prospects of obtaining bakery products. To the date, there is not enough information about the effect of green buckwheat flour additives on the rheological parameters of dough semi-finished products. The solution of this problem formed the basis of the study. According to the conducted research, it is optimal to introduce up to 10% of green buckwheat flour into the dough semi-finished product. In these dosages, green buckwheat flour does not have a negative effect on the rheological properties of the dough. Therefore, the resulting mixture can be used for standard bread production technologies. In addition, the addition of green buckwheat flour in the quantities described has a positive effect on the farinograph quality number, the stability of the dough and the degree of softening of the dough compared to the check sample

Theoretical prerequisites for substantiating the parameters of a rotary ripper for interrow potato cultivation

The article is devoted to the study of the process of interaction of the rotary ripper’s working bodies with the soil. The classification of rotary machines and implements according to the energy transmitted to the working body and the location of the rotation axis is outlined. The article notes that the main characteristics of the rotor work body motion are the trajectory type, the magnitude and direction of velocity of its most characteristic point, and in some cases, the magnitude and direction of acceleration. The article presents the results of theoretical research in the field of kinematics of interaction of rotary working tools with the soil. The design of the rotary ripper is presented and the description of the trajectory of its working bodies is made, the value of movement of the scraper plate in the contact area with the soil is established. We analyzed the segment of the path from the beginning of contact with the soil (the beginning of dragging the surface layer of soil) and the end of contact (the end of dragging the surface layer of soil), on the line of which weed combing, loosening and destruction of soil crust occurs

Digital Echelons and Interfaces within Value Chains: End-to-End Marketing and Logistics Integration

[EN] The goals of real business in the context of the digital transformation of international logistics networks and marketing channels have necessitated the application of a scientifically based theoretical approach to the development of a formalized description acceptable for predictive planning based on leading indicators. In the context of globalization and interstate and regional economic unions, this will lead to achieving the maximum end-to-end integration of digital platforms. Based on the analysis, the article presents the integration of digital logistics and marketing approaches with the mathematical models of the ecosystem organization of economic relations. The features of the organization of economic relations between contractors involved in the execution of virtual transactions and the material movement of resources were analyzed. The researchers considered prerequisites for the analytical description of interconnections between the participants of digital platforms in cross border e-commerce. The authors' approach is based on the idea of both a sales funnel in marketing and a conversion funnel in digital transformation. Considering the integration of logistics and marketing, authors offer the definition of business echelons as stages of the consumer value creation. The theoretical contribution of this article consists in constructing a mathematical description of business echelons along the entire value chain. The developed analytical description of business echelons is acceptable both for embedding a digital management support system into various software products, and for conducting in-depth analysis and finding optimal solutions.The research of S.E.B., S.M.S. and I.V.K. is partially funded by the Ministry of Science and Higher Education of the Russian Federation under the strategic academic leadership program Priority 2030 (Agreement 075-15-2021-1333 dated 30 September 2021).Barykin, SE.; Smirnova, EA.; Chzhao, D.; Kapustina, IV.; Sergeev, SM.; Mikhalchevsky, YY.; Gubenko, AV.... (2021). Digital Echelons and Interfaces within Value Chains: End-to-End Marketing and Logistics Integration. Sustainability. 13(24):1-18. https://doi.org/10.3390/su132413929S118132

First Observation of barB0 to D*0 pi+pi+pi-pi- Decays

We report on the observation of B0bar -> D*0 pi+ pi+ pi- pi- decays. The branching ratio is (0.30 +/- 0.07 +/- 0.06)%. Interest in this particular mode was sparked by Ligeti, Luke and Wise who propose it as a way to check the validity of factorization tests in B0bar -> D*+ pi+ pi- pi- pi0 decays.Comment: 11 pages postscript, also available through http://w4.lns.cornell.edu/public/CLNS, Version to appear in Phys. Rev.