bluuebunny/crossref_metadata_2025_split huggingface dataset:
Generic complexity of algorithmic problems over Brandt semigroups
Authors: Rybalov Alexander 
Published: February 2021

Abstract
In this paper we present a generic polynomial algorithm for the problem about the sum of subset over Brandt semigroup with index set ℕ over any finitely defined group with polynomially decidable word problem. The problem about the sum of subset is a classical combinatorial problem, studied for many decades. This problem is very popular in cryptography, where there are many cryptosystems based on it. Myasnikov, Nikolaev, and Ushakov in 2015 introduced analogs of the problem about the sum of subset for arbitrary groups (semigroups). There are Brandt semigroups for which this problem is NP-complete. Also we propose a polynomial generic algorithm for the problem of identity checking over all finite Brandt monoids

B
n
1

. This problem is co-NP-complete in the classical sence. Generic algorithms solve problems for almost all inputs with respect to some natural measures on the set of inputs. Supported by Russian Science Foundation, grant 18-71-10028.
Numerical research of placement problem on lines with forbidden zones and routing communications
Authors: Zabudsky G G , Veremchuk N S 
Published: February 2021

Abstract
This paper discusses of placement problem of connected equipment (facilities) on parallel lines with forbidden zones. You can’t place equipment inside of forbidden zones. The facilities are connected among themselves and with zones by some kind of communications. The communications (routing of communications) between the facilities and between facilities and zones located on adjacent lines pass through the vertical equipment (viaduct). The target is to find the facilities placement on lines outside zones. Facilities do not must intersect among themselves. It is necessary to minimize the total cost of communications facilities among themselves and with zones. Practical usage of this problem is found, for example, in technology in the design of engineering devices. We consider cases when the viaduct placement is fixed and when its optimal placement is found. The goal function’s value for a fixed viaduct with a specified placement step is compared with the goal function for optimal placement of the viaduct. The results of numerical experiments are presented.
Implementation of new methods for non-destructing testing of diffusion coefficient in porous material products
Authors: Belyaev V P , Varepo L G , Belyaev P S , Divin A G , Pavlinov V V , Nagornova I V 
Published: February 2021

Abstract
New methods for non-destructive testing of diffusion coefficient in thin-sheet and massive products made of isotropic and anisotropic porous materials are considered. In contrast to the rigid structure in the known methods, the represented methods are more flexible in implementing measurement procedures due to higher accuracy of measuring the desired coefficient. Flexibility is provided by calculating experimental data in the preferred sections and by choosing there the static characteristic of the transducer with a stable and noise-proof output signal and in the ranges with high sensitivity to changes in parameters. Expressions for calculating the desired diffusion coefficient for each test subject and a generalized sequence of measurement procedures are introduced. The modified version of the information and measurement system for implementing the proposed methods is described, and the results of the research are presented.
Mathematical methods for determining the guaranteed accuracy of the components content in a mixture made by a conveyor non-mixer
Authors: Evseev A V , Preys V V , Lapina V A , Kasatkin G V 
Published: February 2021

Abstract
In work two mathematical techniques of studying of quality of mixes of heterogeneous (tubular) components (length gages) based on the analysis of synthesis of mix in automatic conveyor non-mixer with use of two and more drum dozers are considered. The relevance and novelty of development are shown on examples of receiving the general party of composite tubular product from small similar parties, at the determined forming of its uniformity, with the set qualitative and quantitative characteristics from heterogeneous tubular components. The criteria allowing determining the required guaranteed accuracy of maintenance of components in the mixes received on installation are also offered.
Acousto-optical method for measuring the displacements of a laser beam in two directions orthogonal to its axis
Authors: Leun E V 
Published: February 2021

Abstract
The issues of improving the method for controlling the two-coordinate displacements Δly and Δlz of a laser beam in the OY and OZ directions orthogonal to its OX axis are considered. It is proposed to use a fiber photodetector with a micro-optical lens at the input of the light guide to register the interference picture produced in the Fresnel zone by the first and zero diffraction orders formed by an acousto-optical (AO) modulator.
In the method, it is proposed to use a prismatic optical scheme placed in front of a single-axis AO modulator for a laser beam displaced Δly and Δlz along two axes OY and OZ, forming two output beams. For the first beam, displacements along the OY axis are excluded: Δly-var, Δlz=0, and the second beam is rotated relative to the first beam by 90° around the OX axis (i.e., Δly→Δlz) with the same exception of displacements along the OY axis with the achievement of the following: Δly=0, Δlz-var. This technique allows you to use a single-axis (1D) AO modulator to control the two-coordinate (2D) displacements Δly, Δlz of the initial laser beam. We also discuss the implementation of a differential measurement method by using two phase measuring devices: an interpolator and a phase meter, and the effect of signal noise on the resolution.
Practice of the VOF Open Foam techniques aimed to parameters prediction of the « dampening solution - paper» interaction for the printing systems
Authors: Orlova E Yu , Chernaya I V , Sultanova Yu M , Rovenskikh A A , Varepo L G , Trapeznikova O V 
Published: February 2021

Abstract
The results of CFD research using the VOF method with Open Foam open source are presented. In the process of study, we built a digital model allowing us to analyze and predict the process of interaction of the dampening solution with substrate (paper) surface in the measuring cell of the PDA ultrasonic device. Discretization of the area for calculation was created using the blockMesh utility. A block-structural hexahedral computational grid has been constructed. The computational grid area is presented in such a way that the number of cells increases in the direction of the paper sample. The visualization of calculations in the ParaView package coincides with the time intervals obtained on the PDA ultrasonic measuring device. The practical significance of the study lies in the realization of the possibility to evaluate the dampening solution parameters, to control the modes of its supply, taking into account the use of modern papers and printing systems.
Improving the efficiency of setting up a five-axis CNC machine in processing of helical gears using a three-dimensional probe
Authors: Safarov D T , Kondrashov A G 
Published: February 2021

Abstract
The most universal method of gear cutting is the method of processing the gear rims of wheels with a universal tool-disk cutters. The main dimension parameter of the gear ring, which is key for ensuring the efficiency of the gear train, is the length of the overall normal. Accurate determination of this parameter is possible only if withdrawal after trial machining and measuring it on a dedicated co-ordinate measuring machine, lost time for the process measurement details, there is a risk of adjustment in marriage. The article considers a method for measuring the length of the General normal of a skewed cylindrical wheel, which allows obtaining its exact value without removing the part after gear processing and measuring this parameter if only one cavity of the gear wheel is processed. Measurements are made using a three-dimensional linear measurement probe. Formulas for calculating the length of the General normal are given, which allow calculating the value of the length of the General normal based on the data of a three-dimensional probe. Comparison of the measurement data of gears with a three-dimensional probe and a specialized CNC gear measuring machine allows us to conclude that the measurement accuracy is sufficient in comparison with the accepted tolerance for the length of the General normal. The introduction of the method of measuring the length of the common normal with a three-dimensional indicator allowed to completely eliminate the probability of commissioning defects and reduced the complexity of carrying out machine changeovers in the mode of single and small-batch processing of gears.
Visual level measurement system application in the technological process automated control system of the recuperative furnace bath
Authors: Valke A A , Lobov D G , Shkaev A G , Shkaev A A , Ponomarev D B 
Published: February 2021

Abstract
The paper considers the melted material level determining problem in the recuperative furnace bath melter in technological process automated control system for the basalt mineral fiber production. To solve this problem, it is proposed to use a visual level measurement system based on the analysis and processing of the melt boundary image. A block diagram of the visual level measurement system developed by the authors is presented, and an algorithm for determining the melt level using a modified Sobel edge detection method is proposed.
Finding ways to improve the performance of welded joints based on controlled heat input and use of shock-mechanical treatment
Authors: Saraev Yu N , Kamantsev I S , Grigoryeva A A , Kuznetsov A V , Semenchuk V M , Nepomnyashchiy A S 
Published: February 2021

Abstract
The paper summarizes the study’s results of welded joints fatigue failure obtained by arc welding with controlled and uncontrolled heat input and shock-mechanical treatment. Based on energy parameters of the mode fixed in welding process of samples obtained at various technologies, the experiments on determination of their fatigue life were performed. The results of numerical estimation of fatigue failure of welded joints made of 09G2S steel are presented. The positive influence of shock-mechanical treatment on test samples durability is shown.
Effect of asymmetric deformation dynamics in amoeboid organism on its search ability
Authors: Saito Kenta , Suefuji Naoki , Kasai Seiya 
Published: February 2021

Abstract
We investigate the effect of asymmetric deformation dynamics in an amoeboid organism on its search ability using a model amoeba. The model represents the behaviours of the amoeboid organism and its search ability is evaluated by searching for the solution to a Boolean satisfiability problem (SAT). We found that the efficiency of the search is significantly improved by implementing asymmetric delays in response to the feedback signals that increase and decrease the variable under appropriate errors. The results indicate that the model could search around the variable vector space by means of the appropriate combination of the inherent local search in the model and the error-induced global search. The results also show that the asymmetric response delays bias the variable to the values that can satisfy the SAT. We also demonstrate that an analog electronic system implementing the amoeba model with asymmetric dynamics possesses the search characteristics of the model.
A bioinspired navigation strategy that uses magnetic signatures to navigate without GPS in a linearized northern Atlantic ocean: a simulation study
Authors: Taylor Brian K , Bernish Margaret K , Pizzuti Susan A , Kehl Catherine E 
Published: February 2021

Abstract
Certain animal species use the Earth’s magnetic field (i.e. magnetoreception) in conjunction with other sensory modalities to navigate long distances. It is hypothesized that several animals use combinations of magnetic inclination and intensity as unique signatures for localization, enabling migration without a pre-surveyed map. However, it is unknown how animals use magnetic signatures to generate guidance commands, and the extent to which species-specific capabilities and environmental factors affect a given strategy’s efficacy or deterioration. Understanding animal magnetoreception can aid in developing better engineered navigation systems that are less reliant on satellites, which are expensive and can become unreliable or unavailable under a variety of circumstances. Building on previous studies, we implement an agent-based computer simulation that uses two variants of a magnetic signature-based navigation strategy. The strategy can successfully migrate to eight specified goal points in an environment that resembles the northern Atlantic ocean. In particular, one variant reaches all goal points with faster ocean current velocities, while the other variant reaches all goal points with slower ocean current velocities. We also employ dynamic systems tools to examine the stability of the strategy as a proxy for whether it is guaranteed to succeed. The findings demonstrate the efficacy of the strategy and can help in the development of new navigation technologies that are less reliant on satellites and pre-surveyed maps.
Stem cells based in vitro models: trends and prospects in biomaterials cytotoxicity studies
Authors: Ahmed Uzair , Ahmed Rashid , Masoud Muhammad Shareef , Tariq Muhammad , Ashfaq Usman Ali , Augustine Robin , Hasan Anwarul 
Published: February 2021

Abstract
Advanced biomaterials are increasingly used for numerous medical applications from the delivery of cancer-targeted therapeutics to the treatment of cardiovascular diseases. The issues of foreign body reactions induced by biomaterials must be controlled for preventing treatment failure. Therefore, it is important to assess the biocompatibility and cytotoxicity of biomaterials on cell culture systems before proceeding to in vivo studies in animal models and subsequent clinical trials. Direct use of biomaterials on animals create technical challenges and ethical issues and therefore, the use of non-animal models such as stem cell cultures could be useful for determination of their safety. However, failure to recapitulate the complex in vivo microenvironment have largely restricted stem cell cultures for testing the cytotoxicity of biomaterials. Nevertheless, properties of stem cells such as their self-renewal and ability to differentiate into various cell lineages make them an ideal candidate for in vitro screening studies. Furthermore, the application of stem cells in biomaterials screening studies may overcome the challenges associated with the inability to develop a complex heterogeneous tissue using primary cells. Currently, embryonic stem cells, adult stem cells, and induced pluripotent stem cells are being used as in vitro preliminary biomaterials testing models with demonstrated advantages over mature primary cell or cell line based in vitro models. This review discusses the status and future directions of in vitro stem cell-based cultures and their derivatives such as spheroids and organoids for the screening of their safety before their application to animal models and human in translational research.
Robust short-term scheduling based on information-gap decision theory for cascade reservoirs considering bilateral contract fulfillment and day-ahead market bidding in source systems
Authors: Yu Xuguang , Li Gang , Li Yapeng , Cheng Chuntian 
Published: February 2021

Abstract
China is implementing a new power system reform, with one goal of renewable energy absorption such as hydropower. However, the forthcoming spot market challenges cascade hydropower generation in terms of the short-term hydro scheduling (STHS) problem. Specifically, STHS involves fulfilling bilateral market obligations and bidding for the day-ahead market with uncertainty. Coordination of these two tasks while managing market risks becomes a problem that must be urgently solved. Herein, we propose a method based on the information-gap decision theory (IGDT) to solve the cascade hydropower STHS problem, wherein the aforementioned tasks are coordinated simultaneously. The IGDT method was used to deal with the uncertainty of the day-ahead market price, and the robustness function was derived. A mixed-integer nonlinear programming model was used to describe the proposed problem, and a commercial solver was used to solve it. A four-reservoir cascade hydropower company was used as the research object. Through the robust dispatching results, the preset profit objectives of the power generation company were satisfied within the price information gap, and the day-ahead market bidding strategy and daily contract decomposition curve were obtained. The proposed model is found to be superior to the scenario-based probability method. Moreover, a comparative analysis of bilateral contract fulfillment showed that more profits can be obtained by coordinating contract fulfillment in the day-ahead market.
The effect of current and future maternal exposure to near-surface ozone on preterm birth in 30 European countries—an EU-wide health impact assessment
Authors: Ekland Johan , Olsson David , Forsberg Bertil , Andersson Camilla , Orru Hans 
Published: February 2021

AbstractPreterm birth is the largest contributor to neonatal mortality globally and it is also associated with several adverse health outcomes. Recent studies have found an association between maternal exposure to air pollution and an increased risk for preterm birth. As a constituent of air pollution, ozone is a highly reactive molecule with several negative health effects when present near earth’s surface. This health impact assessment aims to estimate the proportion of preterm births—in current and future situations—attributable to maternal ozone exposure in 30 European countries (EU30). A literature search was performed using relevant keywords, followed by meta-analysis with STATA software in which five studies investigating exposure-response relationship of interest were included. The attributable proportion, and number of cases, was modelled with the software AirQ+ against current and future European ozone concentrations. According to our meta-analysis, the relative risk for giving birth preterm was calculated to 1.027 (95% CI 1.009–1.046) per 10μg m−3increase in ozone concentration. This rendered 7.1% (95% CI 2.5–11.7) of preterm births attributable to maternal ozone exposure to in EU30 during 2010, which is equal to approximately 27 900 cases. By 2050, the projected decrease in ozone precursor emissions rendered an estimated 30% decrease of ozone attributable preterm births. Not taking emission change into account, due to climate change the ozone-related preterm birth burden might slightly increase by 2050 in Central and Southern Europe, and decrease in Eastern and Northern Europe. In summation, these numbers make a substantial impact on public health.
Nutrient enrichment changes water transport structures of savanna woody plants
Authors: Costa Lucas Silva , De Moura Clapton Olimpio , Bucci Sandra Janet , Sonsin-Oliveira Julia , Gomes Sueli Maria , Bustamante Mercedes Maria Da Cunha 
Published: February 2021

Abstract
Brazilian savanna is a seasonally dry biome, highly diverse and distributed mainly on nutrient-limited soils. Interactions between water stress and nutrient availability are important evolutionary filters in these environments. Previous evidence indicated that reducing the nutritional limitation increases growth rate, optimizes water transport and decreases stomatal conductance in woody plants. However, the anatomical mechanisms that explain such responses are not well-understood. We studied the effects of long-term (20 years) nutrient addition (N, NP and P) on soil chemistry and hydraulic morphological and anatomical traits in six dominant woody savanna species. Nutrient addition and decrease in soil moisture, probably related to changes in grass cover, influenced the plant hydraulic traits at the anatomical level, namely increasing the xylem vessels’ diameter. Consequently, the specific theoretical xylem conductivity (K
tx) increased in five species under NP and P addition. Additionally, the stomatal pore index (SPI) decreased with species-specific responses regarding the intrinsic water use efficiency (iWUE). Four species had higher vulnerability to cavitation (l
vul) under NP and P addition. Using community-weighted mean and structural equation modeling approaches, we observed that nutrient enrichment at the community level did not affect iWUE, while the vulnerability to cavitation (l
vul) strongly increased. The K
tx and SPI were positively and negatively affected by nutrient addition, respectively, but the effects were not as strong as expected due to contrasting species responses. These changes optimized water transport with a hydraulic safety cost and reduced water loss. In comparison with responses to N addition, the greater P-limitation in Cerrado vegetation explains the inter-specific convergence in the responses of P-fertilized individuals. We showed that long-term responses to increased nutrient availability in dystrophic soils include anatomical changes in savanna woody vegetation with relevant interactions with soil-plant–atmosphere water relations.
Modest capacity of no-till farming to offset emissions over 21st century
Authors: Graham Michael W , Thomas R Quinn , Lombardozzi Danica L , O’Rourke Megan E 
Published: February 2021

Abstract
‘No-till’ (NT) agriculture, which eliminates nearly all physical disturbance of the soil surface on croplands, has been widely promoted as a means of soil organic carbon (SOC) sequestration with the potential to mitigate climate change. Here we provide the first global estimates of the SOC sequestration potential of NT adoption using a global land surface model (LSM). We use an LSM to simulate losses of SOC due to intensive tillage (IT) over the historical time period (1850–2014), followed by future simulations (2015–2100) assessing the SOC sequestration potential of adopting NT globally. Historical losses due to simulated IT practices ranged from 6.8 to 16.8 Gt C, or roughly 5%–13% of the 133 Gt C of global cumulative SOC losses attributable to agriculture reported elsewhere. Cumulative SOC sequestration in NT simulations over the entire 21st century was equivalent to approximately one year of current fossil fuel emissions and ranged between 6.6 and 14.4 Gt C (0.08–0.17 Gt C yr−1). Modeled increases in SOC sequestration under NT were concentrated in cool, humid temperate regions, with minimal SOC gains in the tropics. These results indicate that the global potential for SOC sequestration from NT adoption may be more limited than reported in some studies and promoted by policymakers. Our incorporation of tillage practices into an LSM is a major step toward integration of soil tillage as a management practice into LSMs and associated Earth system models. Future work should focus on improving process-understanding of tillage practices and their integration into LSMs, as well as resolving modeled versus observed estimates of SOC sequestration from NT adoption, particularly in the tropics.