Similarity Criteria Research Articles

Adaptable software tools for searching objects-analogues tasks in NO-CODE concept

The paper is devoted to the problem of methodological and software support for the search of object analogues, performed when solving the problems of modelling and designing the development of oil and gas fields. The article shows that there is no single generally accepted methodology for searching analogues, existing methodologies differ in applied similarity criteria and search algorithms, are adapted to the search conditions, and are modernised. With the inconsistency of methods computer programs for searching analogues are created at a low level of abstraction, for a limited range of tasks, the existing developments are integrated with corporate databases and in general do not solve the problem of providing analysts with pro-software tools. As a solution we propose the development of programs for searching analogues in the concept of "no-code" (without programming) on the basis of analytical platforms. The "no-code" approach will allow analysts without involving programmers to create software tools for searching analogues, implementing their own variant methods. The article presents the authors' algorithm for express analysis of data at the initial stage of analogue search and the software tool that implements it, created "no code" on the basis of the Russian analytical platform Loginom.

On Additional “Multi-Scale” Similarity Criteria for Experimental Work-Out of Aerospace Engineering Products

On Additional “Multi-Scale” Similarity Criteria for Experimental Work-Out of Aerospace Engineering Products

FEATURES OF THE BOUNDARY LAYER ORGANIZATION IN TESLA DISC TURBINES

To ensure maximum efficiency of bladeless Tesla turbines, it is important to maintain a laminar flow regime within the boundary layer that forms on the disc surfaces. Depending on the flow regime, the state of the disc surfaces, and the geometry of the interdisk gaps, the nature of the boundary layer varies. It is crucial for the flow regime to remain laminar, and the distance between the discs should not exceed twice the thickness of the boundary layer. Experimental investigations of the characteristics of the boundary layer during the flow around turbine blades were proposed to determine the parameters necessary for achieving maximum efficiency. These experiments were conducted in an aerodynamic test rig that provided a uniform velocity field with minimal turbulence (0.7 %) within a speed range up to 0.33 Mach. The primary focus of these studies was to determine the location of the transition zone within the boundary layer, which allows for the examination of conditions for stable maintenance and characteristics of laminar flow. The transition zone was determined based on changes in the tangential friction stress in the experiments. The obtained results facilitated the establishment of the necessary dimensions for the inter-disk gaps and the optimum values of the similarity criterion Re from the perspective of flow regime. For a smooth surface, laminar flow within the boundary layer is maintained up to a relative coordinate of 0.17 x= from the start of the surface, across a wide range of Reynolds numbers. For a rough surface, the extent of the zone with a laminar boundary layer is approximately the same as that for a smooth surface at Re=3.6∙105. However, at Re=7.4∙105 the laminar flow terminates slightly earlier, at 0.13 x= , with a very short transitional zone between laminar and turbulent flow characteristics. The thickness of the laminar boundary layer on a smooth surface is 0.5…0.7 mm, while for a rough surface, it is slightly greater at 0.7…0.8 mm. Therefore, to ensure high efficiency of Tesla disc turbines, the distance between the discs should be maintained at 1…1.5 mm, considering the requirements for laminar flow.

Design parameters of water intake chambers on water supply channels of pumping stations

The research is devoted to improving the working conditions of chamber water intakes of pumping stations (PS) on water supply channels, which is one of the main factors determining the efficiency of operation of pumping units and stations. An analysis of the current state of the operating conditions of chamber water intakes according to field surveys and literary sources shows that the dimensions of the water intake chambers were assigned based on the minimum energy loss in the suction pipeline of the pump, which, in conditions of high turbidity of water, leads to siltation and complicates the operation of pumping stations. When the water intake chambers are silted, its hydraulic resistance increases, air vortex funnels are formed, the water supply of the pump decreases and the likelihood of cavitation phenomena increases. A significant amount of work has been devoted to the issues of improving the hydraulic characteristics of the flow in the fore chamber and water intake chambers. Therefore, without duplicating them, we conducted research to establish the effect of silting of the chambers on the value of the hydraulic resistance of the suction pipeline and to develop measures to improve the hydraulic characteristics of the intake chamber under conditions of operation in a suspension-carrying flow. To solve the problem, a laboratory stand was made that simulates hydraulic processes in natural conditions based on modeling methods, taking into account the preservation of the constancy of the main similarity criteria.

A hue preserving uniform illumination image enhancement via triangle similarity criterion in HSI color space

A hue preserving uniform illumination image enhancement via triangle similarity criterion in HSI color space

USE OF ANALYTICAL MODEL FOR SYNTHESIS OF ALGORITHMS FOR CONTROL OF TRANSPORT CONVEYOR PARAMETERS

This study presents a methodology for synthesizing optimal control algorithms for the flow parameters of a conveyor-type transport system with a variable transport delay. A multi-section transport conveyor is a complex dynamic system with a variable transport delay. The transport conveyor is an important element of the production system, used to synchronize technological operations and move material. The Analytical PiKh-model of the conveyor section was used as a model for designing a control system for flow parameters. The characteristic dimensionless parameters of the conveyor section are introduced and the similarity criteria for the conveyor sections are determined. The model of a conveyor section in a dimensionless form is used to develop a methodology for synthesizing algorithms for optimal control of the flow parameters of a transport conveyor section. The dependencies between the value of the input and output material flow of the section are determined, taking into account the initial distribution of the material along the conveyor section, variable transport delay, restrictions on the specific density of the material, and restrictions on the speed of the belt. The dependencies between the value of the input and output material flow for the case of a constant transport delay are analyzed. A technique for synthesizing algorithms for optimal belt speed control based on the PiKh-model of a conveyor section is presented. As a simplification, a two-stage belt speed control is considered. Particular attention is paid to the methodology for synthesizing optimal control algorithms based on the energy management methodology (TOU-Tariffs). The criteria of control quality are introduced and problems of optimal control of flow parameters of the transport system are formulated. Taking into account differential connections and restrictions on phase variables and admissible controls, which are typical for the conveyor section, the Pontryagin function and the adjoint system of equations are written. As examples demonstrating the design of optimal control, algorithms for optimal control of the flow parameters of the transport system are synthesized and analysis of optimal controls is performed.

Random wave action on pile group foundations with complex geometry for sea-crossing bridges

To explore the mechanical properties of pile group foundations (PGFs) with complex geometry in sea-crossing bridges under ocean wave action, this study develops a numerical model for predicting wave loads on PGFs under multidirectional random wave action. Furthermore, an experimental model of the PGF composed of a quasi-elliptical pile cap and 13 tilted piles is designed and made based on the gravity similarity criterion. By performing model experiments and numerical analysis, the mechanical characteristics of the PGF model under random wave action, the effect of principal wave direction angle and random wave directionality, and the influence of the pile cap on wave loads of tilted piles are systematically investigated. The results show that the calculated results of the presented numerical model match well with the experimental data. The frequency characteristics of wave loads on the PGF model are mainly determined by the wave spectrum. The increase of the significant period improves the contribution of the pile group to the horizontal wave loads on the PGF. The effect of the principal wave direction on the vertical wave loads on the PGF is not obvious under the experimental wave conditions. Neglecting the wave directionality will overestimate the wave loads in the principal wave direction and vertical direction on the PGF. Under the influence of diffraction waves from the pile cap, the wave loads on the pile group and the piles where the wave finally acts are easily amplified when the wave number is small, but in the large wave number case, the wave loads on the pile group and the piles below the middle of the pile cap may be weakened.

New Digital Field of Drawing and Survey for the Automatic Identification of Debris Accumulation in Flooded Areas

Floods are among the most devastating natural hazards in the world, causing the largest percentage of deaths and property damage. The impact of floods can be mitigated with an adequate knowledge of the territory, which makes it possible to better organize prevention plans with an appropriate analysis of the risk areas, which allows the management of relief efforts quickly and adequately. This work presents a methodology for mapping and monitoring the areas affected by floods and landslides by remote sensing: the correct representation and full interpretation of the territory matrix are essential for quality and sustainability design. In this paper, we used tools and technology that allow us to analyze and visualize the landscape evolution. The calibration of the method was performed on the events that took place in Calabria, in Southern Italy, on 12 August 2015. The proposed methodology concerned the planning of acquisition flights, the selection and setting of the sensors used, and the processing and post-processing of the data collected through the application of algorithms used for data manipulation and interpretation. The process of recognizing the areas with deposits of debris through the spectral signature was carried out using similarity criteria relating to hyperspectral data. The results obtained recommend the adoption of this methodology to deal with emergencies due to flood events.

A new similarity criterion and design method for wind tunnel model tests of floating offshore wind turbines

Floating offshore wind turbines (FOWTs) have received strong attention in recent years, and numerous experimental studies have been conducted on them. However, the small-scaled wind turbine models designed by the criterion of traditional thrust coefficient similarity are unable to obtain similar power coefficients with the prototype, and they are not able to reflect the expected dynamic aerodynamics induced by the platform motions. To this end, this paper presents a new criterion for wind tunnel model tests based on the mapping of the optimal tip speed ratio (TSR) and the similarity of the changing rate of the relative TSR. The National Renewable Energy Laboratory's offshore 5-MW wind turbine is selected as the prototype wind turbine. The blade of the model wind turbine is generated by NACA 4412 airfoil, and the chord and twist are optimized by the genetic algorithm. The objective is to keep the thrust and power coefficients of the model wind turbine around the optimal TSR consistent with that of the prototype through a linear mapping relationship. Dynamic simulations with the Unsteady Blade-Element Momentum method are performed to verify the new similarity criterion at different surge frequencies. Compared with those of the model wind turbine designed by the traditional method, fluctuations of the mapped thrust and power coefficients of the new model are in better agreement with the prototype. Hysteresis effects with respect to the relative TSR are newly captured, and loops of the new model are also closer to that of the prototype. This paper provides a more reasonable criterion for wind tunnel model tests of FOWTs, and the dynamic aerodynamics of the prototype can be reflected more accurately compared with the traditional method, which is important for the performance evaluation and optimization design of large-scale FOWTs.

ON THE ISSUE OF THE RELATIONSHIP BETWEEN THE LABOR AND CORPORATE STATUS OF THE COMPANY'S CHIEF EXECUTIVE AS A SPECIAL REPRESENTATIVE OF A LEGAL ENTITY

The article examines the legal status of a company's chief executive. The ambiguity of the company's chief executive's status, taking into account the nature and goals of establishing the organization, creates a variety of means to regulate the chief executive's status by sector specific legislation. The issue of the relationship between the labor and corporate status of the company's chief executive is especially important, as well as that of criteria for similarity and differentiation of statuses. The answer to this problem lies in the essence of corporate organizations. The purpose of the study is to trace the similarity and difference between the labor and corporate status of a company's chief executive in a corporate organization based on the analysis of regulatory legal acts of various industry affiliation and to propose criteria for their correlation. The methodological basis of the study was the dialectical approach, systematic, logical methods, formal legal and other methods of scientific cognition. The authors note that the study of the issue leads to the conclusion that the labor status of a company's chief executive in a corporate organization is dependent on the corporation. The article proposes similarity criteria and differentiation criteria of the labor and corporate statuses of a company's chief executive in a corporate organization: similarity of both statuses – labor and corporate – lies only in general orientation of the nature of the activity carried out by the company's chief executive: they are the executive body in the organization; the criterion of differentiation: the existence of an employment contract of the company's chief executive . At the same time, while remaining in the corporate status, the company's chief executive is obliged to adhere to the norms of labor legislation in relations with the employees.

Effects of Radiant Floor Heating Integrated with Natural Ventilation on Flow and Dispersion in a Newly Decorated Residence.

To date, few studies have been conducted on the characteristics of flow and dispersion caused by indoor radiant floor heating integrated with natural ventilation. In this study, we employed reduced-scale numerical models validated by wind-tunnel experiments to investigate the influence of radiant floor heating integrated with natural ventilation on airflow, heat transfer, and pollutant dispersion within an isolated building. The Richardson number (Ri) was specified to characterize the interaction between the inflow inertia force and the buoyancy force caused by radiant floor heating. Several Ri cases from 0 to 26.65, coupled with cross- or single-sided ventilation, were considered. Model validation showed that the numerical model coupled with the RNG k-ε model was able to better predict the indoor buoyant flow and pollutant dispersion. The results showed that the similarity criterion of Ri equality should be first satisfied in order to study indoor mixed convection using the reduced-scale model, followed by Re-independence. For cross-ventilation, when Ri < 5.31, the incoming flow inertia force mainly dominates the indoor flow structure so that the ACH, indoor temperature, and pollutant distributions remain almost constant. When Ri > 5.31, the thermal buoyancy force becomes increasingly important, causing significant changes in indoor flow structures. However, for single-sided ventilation, when Ri > 5.31 and continues to increase, the buoyancy force mainly dominates the indoor flow structure, causing a significant increase in ACH, thus reducing the indoor average temperature and pollutant accumulation.

Fingerprint-Based Localization and Channel Estimation Integration for Cell-Free Massive MIMO IoT Systems

In this article, we propose a novel localization and channel estimation integration framework for cell-free massive multiple-input–multiple-output (MIMO) Internet of Things (IoT) systems, in which position information supports accurate channel estimation and accurate channel information can, in turn, improve positioning accuracy. Under this integration framework, we propose a two-phase fingerprint-based localization method consisting of both initial and accurate localization phases and a coarse-location-based (CLB) pilot reassignment scheme. The coarse location information for pilot reassignment is obtained in the initial localization phase of the two-phase localization method, and the fingerprint information used in the accurate localization phase is extracted through channel estimation based on the CLB scheme. Furthermore, for localization, two different fingerprint similarity criteria are proposed to meet the requirements of the different localization phases. Simulation results demonstrate that our proposed two-phase fingerprint-based localization method achieves better positioning performance than existing methods, although there is a slight increase in computational complexity compared to the initial localization. Moreover, our proposed CLB pilot reassignment scheme outperforms the conventional pilot assignment schemes in the comprehensive performance considering both channel estimation performance and complexity.

SBCDetector: a hybrid approach to detect second-order similarity or change

Software Configuration Management (SCM) involves tracking similarities/changes during software evolution. Efficient comparison for tracking requires two perspectives—Granularity: comparing the entities at file level, class level, and method level. Second, Robustness should be prominent to detect renaming and shifting that occur as a part of restructuring. Even GIT repository, which is widely used, allows such comparison with renaming and shifting details but is limited to file level only, along with its own limitation of default similarity criteria of above 50%. In this study, the proposed technique named SBCDetector detects similarity/change status with both perspectives that is lacking in the existing literature. Result shows that one-fourth of entities have been found renamed/shifted at three granularities for eight subject systems improving tracking, understandability, and onboarding. Hybrid technique involving fuzzy logic derives classification model with .99 f-score to detect first- and second-order similarity/change.

Transfer learning for landslide susceptibility modeling using domain adaptation and case-based reasoning

Abstract. Transferability of knowledge from well-investigated areas to a new study region is gaining importance in landslide hazard research. Considering the time-consuming compilation of landslide inventories as a prerequisite for landslide susceptibility mapping, model transferability can be key to making hazard-related information available to stakeholders in a timely manner. In this paper, we compare and combine two important transfer-learning strategies for landslide susceptibility modeling: case-based reasoning (CBR) and domain adaptation (DA). Care-based reasoning gathers knowledge from previous similar situations (source areas) and applies it to solve a new problem (target area). Domain adaptation, which is widely used in computer vision, selects data from a source area that has a similar distribution to the target area. We assess the performances of single- and multiple-source CBR, DA, and CBR–DA strategies to train and combine landslide susceptibility models using generalized additive models (GAMs) for 10 study areas with various resolutions (1, 10, and 25 m) located in Austria, Ecuador, and Italy. The performance evaluation shows that CBR and combined CBR–DA based on our proposed similarity criterion were able to achieve performances comparable to benchmark models trained in the target area itself. Particularly the CBR strategies yielded favorable results in both single- and multi-source strategies. Although DA tended to have overall lower performances than CBR, it had promising results in scenarios where the source–target similarity was low. We recommend that future transfer-learning research for landslide susceptibility modeling can build on the similarity criterion we used, as it successfully helped to transfer landslide susceptibility models by identifying suitable source regions for model training.

What is the overlap between malnutrition, frailty and sarcopenia in the older population? Study protocol for cross-sectional study using UK Biobank.

In an increasingly older adult population, understanding the inter-relationship between three age related conditions malnutrition, frailty and sarcopenia is important in order to improve their recognition, treatment and prevention. This study aims to determine the overlap between malnutrition, frailty and sarcopenia by measuring estimates of prevalence for each individual condition. In addition, we will compare two models of frailty which are the accumulation of deficits and phenotype models. This is a cross-sectional study that will use the UK Biobank database, which will include a subset of 381,000 participants: males and females aged 50 years and above who completed the baseline assessments. For the baseline assessments, details of the participants' characteristics will be included. All three conditions will be identified and mapped to variables collected at the baseline assessment. Variables for malnutrition will be mapped according to the Global Leadership Initiative on Malnutrition (GLIM) criteria. Frailty will be defined according to two models: the 36 deficits and the phenotype model. Finally, sarcopenia will be assessed according to the European Working Group on Sarcopenia in Older People (EWGSOP) standard. This proposed study will help to understand the presence of malnutrition, frailty and sarcopenia in the older population and describe any overlap between the conditions. There is little published research on the overlap between these three conditions. Despite the similarity and shared criteria used for the identification of malnutrition, frailty and sarcopenia there is still a lack of cohesive thinking around the overlap of applied definitions and identification criteria. ClinicalTrials.gov NCT04655456 approved on the 10th of December 2020.

Utilization mechanism of foam flooding and distribution situation of residual oil in fractured-vuggy carbonate reservoirs

The development of fractured-vuggy carbonate reservoirs is extremely difficult because of the complex fractured-vuggy structure and strong heterogeneity. Foam flooding is a potential enhanced oil recovery (EOR) technology in fractured-vuggy carbonate reservoirs. Based on the similarity criterion, three types of 2D visual physical models of the fractured-vuggy structure were made by laser ablation technique, and a 3D visual physical model of the fractured-vuggy reservoir was made by 3D printing technology. Then the physical analog experiments of foam flooding were carried out in these models. The experimental results show that foam can effectively improve the mobility ratio, control the flow velocity of the fluid in different directions, and sweep complex fracture networks. The effect of foam flooding in fractures can be improved by increasing foam strength and enhancing foam stability. The effect of foam flooding in vugs can be improved by reducing the density of the foam and the interfacial tension between foam and oil. Three types of microscopic residual oil and three types of macroscopic residual oil can be displaced by foam flooding. This study verifies the EOR of foam flooding in the fractured-vuggy reservoir and provides theoretical support for the application of foam flooding in fractured-vuggy reservoirs.

A numerical rotating water tank can reproduce the Coriolis effect on the urban heat dome flow

Urban heat dome flow forms under calm background conditions, which has large impacts on urban ventilation, building energy consumption and pollutants dispersion. With ongoing rapid and intense urbanisation, an increasing number of megacities have emerged. The hydraulic diameter of megacities can reach beyond than 20 km, leading to the Coriolis force playing an important role in urban heat dome flow over high-latitude cities. In this study, based on the Rossby number similarity criterion, a numerical rotating tank model (length scale of 0.5 m) was designed and compared with the real atmospheric scale (length scale of 20 km) large eddy simulation (LES) models. The reduced-scale model reproduced the deflection behaviour of the urban heat dome flow compared with those of the atmospheric cases at the same Ro number. To quantify the magnitude of deflection, an outflow angle γ in the upper-level divergent outflow region was defined. The outflow angle of the reduced-scale cases agrees well with those of the corresponding atmospheric cases. The velocity fields, temperature fields, vorticity fields, and dome structures were also analysed in both reduced scale numerical reduced-scale cases and real atmospheric scale cases. The computational time in reduced-scale cases can be reduced significantly with acceptable accuracy. These findings suggest that a rotating tank can be used to study the effect of the Coriolis force.

Identification modeling of ship maneuvering motion based on local Gaussian process regression

A fast and accurate nonparametric modeling method based on local Gaussian process regression (LGPR) is proposed for the identification modeling and prediction of ship maneuvering motion. The training dataset collected from the free-running model tests of ship maneuvering is automatically divided into a number of clusters according to the similarity criterion by clustering analysis using k-means algorithm. Utilizing the data in each cluster, the corresponding local nonparametric model is identified. The computational cost of training and prediction based on LGPR is reduced compared to that based on the classic Gaussian process regression (CGPR) using the whole training dataset. Taking the KVLCC2 tanker and an unmanned surface vehicle (USV) as study objects, the nonparametric models are identified based on the experimental data of zigzag maneuvers of the KVLCC2 model and random maneuver of the USV. Using the identified models, the zigzag maneuvers of the KVLCC2 model and the random maneuver of the USV, which are not involved in the training data, are predicted. The results show that LGPR has higher computational efficiency than CGPR with acceptable prediction accuracy.

DC Series Arc Fault Detection Method in Photovoltaic System Based on Multiple Frequency Selections for Common-Mode Conductive Voltage

DC series arc faults are one of the main causes of fire hazards in photovoltaic power systems. The common method of the traditional dc series arc fault detection uses wideband current sensors to obtain the arc current signal, extract arc characteristic frequency components, and make intelligent judgments based on numerous samples. This kind of detection method requires high-performance hardware and has a high cost. This article takes the common-mode conductive voltage (CMCV) signal, which is produced by arc faults, as the object and confirms the feature frequency band of the arc CMCV signal based on the spectral analysis. To obtain the feature frequency component and perform frequency reduction at the hardware level, multiple frequency selection and detection circuits were designed, and the feature quantities of the time and frequency domains were extracted from the output of the circuits. Subsequently, a two-dimensional arc fault feature plane was constructed, and an arc/normal similarity criterion and arc fault judgment algorithm were proposed. Finally, this article discusses or experimentally verifies the effectiveness, reliability, and anti-interference ability of the proposed method. The proposed method is low cost, simple, reliable, and effective and provides a novel idea and approach for dc series arc fault detection.

Numerical Simulation of Close-Range Interference of Main Engine Jet/Rudder

Carrier rockets and certain spaces are usually driven by the tail engine. Some spaces can increase the flap at the end of the aircraft as the control plane. When the main jet engine opens, the jet flow disturbs the body flap seriously. The engine exhausts are usually mixed gas, but it is difficult to numerically simulate multi-component gas directly. Generally, the similarity criterion is adopted to convert hot jet gas medium into cold jet air medium for calculation. In this paper, the numerical simulation of close interference between the main engine jet and the flap is carried out for a simplified aircraft model, and the flow field of jet interference under different incoming Mach numbers is analyzed. The result shows that a similar parameter mass flow ratio can improve the accuracy of numerical simulation.