Scaling Approach Research Articles

Achieving Agility through Auto-Scaling: Strategies for Dynamic Resource Allocation in Cloud Computing

Abstract: Auto-scaling is a crucial aspect of cloud computing, allowing for the efficient allocation of computational resources in response to immediate demand. This article delves into the concept of auto-scaling, its key components, and the strategies used to effectively manage resources in cloud environments. This study emphasizes the importance of auto-scaling in the cloud computing landscape by exploring its benefits, including cost efficiency, performance optimization, high availability, and scalability [1]. The article explores the various factors to consider when implementing scaling policies, such as selecting the right approach for scaling, whether it be predictive or reactive and the availability of auto-scaling services provided by major cloud platforms like Amazon Web Services (AWS), Google Cloud Platform (GCP), and Microsoft Azure [2, 3]. In addition, the paper addresses the challenges and complexities related to configuring auto-scaling systems, cost management, and latency in resource provisioning [4]. The article also showcases case studies that illustrate the successful implementation of auto-scaling in different industries, along with valuable insights and recommended approaches [5]. Lastly, this paper delves into future trends and research directions in auto-scaling techniques, integration with emerging technologies, and potential research areas [6].

Methane production from sugarcane vinasse: The alkalinizing potential of fermentative-sulfidogenic processes in two-stage anaerobic digestion

The two-stage anaerobic digestion (2st-AD) of sugarcane vinasse is widely studied and well-known for improving the energy recovery potential in sugarcane biorefineries. Maintaining enhanced substrate acidification in a separate (first stage) reactor directly improves the performance of methanogenesis (second stage). However, problems derived from the presence of sulfate (SO42−) and the subsequent sulfide formation in the second stage are not prevented in conventional 2st-AD systems. In addition, high costs related to reactor alkalinization still represent significant drawbacks in that configuration. The energy recovery potential via methanogenesis was assessed from acidified sugarcane vinasse samples collected from different dark fermentative systems, namely: V1 (subjected to NaOH+NaHCO3 dosing), V2 (subjected to NaOH dosing) and V3 (subjected to no pH control). Despite the harmfulness of sulfide, the enhanced production of acetate from the incomplete oxidation of organic matter in sulfidogenesis can benefit methanogens. The highest methane yield (296.3 NmL-CH4 g-COD−1) and global energy recovery potential (354,603 GWh per season) were obtained from the lactate and SO42−rich vinasse (V2). Nevertheless, from a technological perspective, the methanogenesis of vinasses subjected to the fermentative-sulfidogenic process (V1) provided a higher quality biogas due to a higher calorific power (26.4-27.0 MJ Nm−3) and decreased H2S content in the biogas. Finally, the fermentative-sulfidogenic process as an alkalinizing strategy was demonstrated to be the best economic approach for scaling up the 2st-AD of sugarcane vinasse, overcoming the main economic drawback of this configuration.

Strategi Konservasi Daerah Tangkapan Air Danau Singkarak

Land use changes that occur in the upstream areas of the watershed will certainly result in changes in the hydrological characteristics of the watershed. Area expansion in the form of land conversion, whether into residential or agricultural land, in the process often does not pay attention to soil and water conservation principles. Therefore, sustainable water catchment management is needed to reduce increasing land degradation. This research uses the Descriptive Analysis method through the Multidimensional Scaling approach. The sustainability status of the Lake Singkarak catchment area based on the results of the RapDTA analysis is in the moderately sustainable category with an index value of 54.87%. If we look at each dimension that is included in the quite sustainable category, it is the economic dimension with an index value of 55.10% and the social dimension with an index value of 50.37%, while the ecological dimension has an index value of 49.88%.

Electroelastic wave dispersion in the rotary piezoelectric NEMS sensors/actuators via nonlocal strain gradient theory

This article introduces a computational means for investigating the electroelastic nonlinear wave dispersion traits of the nano-dimension sandwich pipe, which is composed of a core formed of a bi-directional functionally graded (Bi-FG) material, together with a piezoelectric sensor/actuator. A combination of Hamilton’s principle, first-order shear deformation, along with Von-Karman nonlinearity, is used for modeling and obtaining the nonlinear governing equations of the nano-sized sandwich pipe connected to a piezoelectric part. The nonlinear governing equations to obtain the nonlinear phase velocity of the current system are determined using a combination of analytical and multiple scales approaches. Due to some computational cost for choosing the precise values of both the nonlocality factor and length scale of the nanopipe in the laboratory, for the first time in this research, with the aid of COMSOL multi-physics finite element simulation, the results are verified, and new outcomes for obtaining the exact functions for nonlocal and length scale factors is presented. In addition, an artificial neural network (ANN) is utilized in this study for the prediction of the results. The mathematical and finite element results were used to train the ANN. A newly presented optimization algorithm is exploited for the first time for optimizing the ANN parameters concluding higher accuracy of the ANN predictions. Consequently, to explore the influences of the location of the piezoelectric patch, nonlocality and length scale factors, and applied voltage parameter on the phase velocity characteristics of the nano-dimension sandwich pipe made of a Bi-FG core and electrically patch, an effort is performed. As an applicable result that can be useful in the related nano-industries, the current work presents exact nonlocal and length scale functions for different conditions.

Gravitational wave turbulence: A multiple time scale approach for quartic wave interactions

Gravitational wave turbulence: A multiple time scale approach for quartic wave interactions

Flowback Rates for Pump-In/Flowback Test

Summary The pump-in/flowback test (PIFT), often referred to as the diagnostic fracture injection test (DFIT) with flowback, offers notable advantages in terms of time efficiency and accuracy, particularly in the context of low-permeability formations. The key to the success of this test lies in the careful selection of an optimal flowback rate to yield meaningful results. The fundamental assumption underlying the pressure analysis of these tests is the uniform closure of fractures during the flowback phase, which is considered the default fracture closure mode in current analyses. In this study, we present evidence that challenges the validity of this assumption, highlighting instances where unsuitable flowback rates can lead to nonuniform fracture closure and result in abnormal pressure data. To address this challenge, we identify different closure modes through the signature of fracture closure in the excessive bottomhole pressure decline curve. Subsequently, we propose an optimal range of flowback rates using a scaling analysis approach to obtain a uniform closure mode in an extended openhole section of a vertical well. Our method has been rigorously validated through 3D numerical simulations and field studies, enhancing its reliability and applicability. This approach helps operators to conduct effective tests in complex situations, overcoming a barrier to widespread test application.

Aeroelastic Scaling of a High-Aspect-Ratio Wing Incorporating a Semi-Aeroelastic Hinge

There has been a growing interest in utilizing flared folding wingtips as an in-flight load alleviation device to enable increased wing spans that meet airport gate limits but with little increase in wing weight. The semi-aeroelastic hinge (SAH) concept is implemented in high-aspect-ratio wings to enable wingtips to be released during severe load cases such as maneuvers and gusts to alleviate the bending moments while maintaining optimum aerodynamic shape for the rest of the flight. In this paper, scaling methods for wings incorporating the SAH are explored, allowing for the development of equivalent scaled unmanned aerial vehicles or wind tunnel models with similar aeroelastic behavior as full-size aircraft. Three scaling approaches are considered in this study, namely, Iso-Froude, Iso-Frequency, and Iso-Strain, where a set of governing nondimensional quantities and scaling factors are determined. Despite the significant nonlinearities resulting from large wingtip fold angles, it is shown that a linear scaling approach can be appropriate for such a wing configuration. Furthermore, the aeroelastic properties of each scaled model are compared to those of the full-scale model, where the best match was obtained from the Iso-Strain model, although it is challenging to meet the required operational conditions.

Experimental investigation of countercurrent flow limitation (CCFL) in a 1/19 scale of VVER-1000 geometry

Countercurrent flow limitation (CCFL) has been experimentally considered in a VVER-1000 hot-leg. The proposed test facility consists of a hot-leg pipe, a reactor vessel simulator (RVs), and a steam generator simulator (SGs). It was designed and constructed based on power-to-volume scaling approach by preserving the Froud number in the hot leg. The scaling ratio was considered 1/19 of the Bushehr NPP (VVER-1000) geometry. The hot leg of the proposed facility provides good optical observation of the gas/liquid interface. The SG simulator has also a side view for optical observation. Experimental results were captured at atmospheric pressure with air/water as fluid. CCFL was obtained by analyzing the pressure differences between RV and SG simulators.This CCFL data was compared with empirical data and correlations available in the literature. With increasing liquid superficial velocity, the gas superficial velocity curve is continuously decreased, which is consistent with Navarro's results. In this study, an experimental correlation is proposed and compared to other correlations. It was very close to the Navarro and Richter correlations.The results of experimental investigations clarified the onset of the CCFL phenomenon in a Bushehr NPP (VVER-1000) hot-leg geometry. Moreover, the achieved patterns and behaviors of the air/water mixture would be used in computational fluid dynamics (CFD) code validations.

The quest for down scale representativeness: how to exploit CFD to design a shear study for vaccines

In this work, we exploit computational fluid dynamics (CFD) to evaluate stirred tank reactor (STR) process engineer parameters (PEP) and design a scale-down system (SDS) to be representative of the formulation and filling process steps for an Aluminum adjuvanted vaccine drug product (DP). To study the shear history in the SDS we used the concept of number of passages, combined with an appropriate stirring speed down scale strategy comprising of either (i) tip speed equivalence, widely used as a scale-up criterion for a shear-sensitive product, or (ii) rotating shear, a shear metric introduced by Metz and Otto in 1957 but never used as scaling criterion. The outcome of the CFD simulations shows that the tip equivalence generates a worst-case SDS in terms of shear, whereas the rotating shear scaling approach could be used to design a more representative SDS. We monitored the trend over time for “In Vitro Relative Potency” as DP Critical Quality Attribute for both scaling approaches, which highlighted the crucial role of choosing the appropriate scaling-down approach to be representative of the manufacturing scale during process characterization studies.

Contribution of strong electron-phonon interaction in the transport properties of La0.8Ca0.2Mn0.5Ni0.5O3 system

La0.8Ca0.2Mn0.5Ni0.5O3 NTC (negative thermal coefficient) thermo-sensitive material was prepared using a conventional solid-state reaction method. From the structural results, we found that the material is pure and crystallizes in the orthorhombic structure with a Pnma space group. It is found that the La0.8Ca0.2Mn0.5Ni0.5O3 ceramic can be used as an NTC thermistor compound in specific temperature sensors and attenuators. Based on Holsten's theory, detailed electrical investigations concerning the nature of the activated small polaron hopping mechanism were reported. The temperature dependence of the DC conductance was used to determine the electrical conduction processes that govern the transport properties of La0.8Ca0.2Mn0.5Ni0.5O3. Hence, the DC mechanisms exhibit changes from the variable range hopping at very low temperatures to the non-adiabatic small polaronic hopping at T = 210 K. In the intermediate temperature range, the semiconductor behavior of La0.8Ca0.2Mn0.5Ni0.5O3 was attributed to the contribution of the tunneling transport process. At various temperatures, the conductance spectra were discussed based on Jonscher and Bruce's laws. Contributions of the overlapping-large-polaron-tunneling, the correlated barrier hopping, the quantum mechanical tunneling, and the non-overlapping small polaron tunneling mechanisms to the transport properties were observed in the dispersive region of the conductance spectra. In addition, Summerfield scaling and corrected Summerfield scaling approaches prove that the charge mobility is temperature-dependent. The positive value of the correction parameter α = 1.2 confirms the presence of interactions in the studied sample.

Designated‐time stabilizing strategy for a class of time‐varying nonlinear systems and its application to pendulum system

AbstractIn this paper, a new scheme is proposed to stabilize a class of nonlinear systems within a designated time, mainly motivated by two unsolved problems: the singularity caused by infinity control magnitudes at the prescribed time instant and the lack of formulating/manipulating state responses after the prescribed time. Under the proposed scheme, an exquisite controller is constructed by entailing both the state scaling approach and a finite‐time stabilizing procedure. It is shown that the obtained control is well defined with bounded magnitude on the whole‐time horizon and ensures the existence of the solutions of the closed‐loop system. Superior to the existing prescribed time stabilization results, the proposed method is capable of ensuring that the states of the closed‐loop system converge to a small compact set within the designated time, stay inside it thereafter and perform finite‐time convergence eventually. Simulation examples are presented to illustrate the effectiveness of the proposed approach.

Scaling approaches and macroecology provide a foundation for assessing ecological resilience in the Anthropocene.

In the Anthropocene, intensifying ecological disturbances pose significant challenges to our predictive capabilities for ecosystem responses. Macroecology-which focuses on emergent statistical patterns in ecological systems-unveils consistent regularities in the organization of biodiversity and ecosystems. These regularities appear in terms of abundance, body size, geographical range, species interaction networks, or the flux of matter and energy. This paper argues for moving beyond qualitative resilience metaphors, such as the 'ball and cup', towards a more quantitative macroecological framework. We suggest a conceptual and theoretical basis for ecological resilience that integrates macroecology with a stochastic diffusion approximation constrained by principles of biological symmetry. This approach provides an alternative novel framework for studying ecological resilience in the Anthropocene. We demonstrate how our framework can effectively quantify the impacts of major disturbances and their extensive ecological ramifications. We further show how biological scaling insights can help quantify the consequences of major disturbances, emphasizing their cascading ecological impacts. The nature of these impacts prompts a re-evaluation of our understanding of resilience. Emphasis on regularities of ecological assemblages can help illuminate resilience dynamics and offer a novel basis to predict and manage the impacts of disturbance in the Anthropocene more efficiently. This article is part of the theme issue 'Ecological novelty and planetary stewardship: biodiversity dynamics in a transforming biosphere'.

Bioconversion of hemicellulosic fraction of wheat straw biomass to bioethanol by Scheffersomyces stipitis: A kLa-based scale-up study

The potent utilization of hemicellulosic fraction, which comprises one-third of carbohydrates in lignocellulosic biomass (LCB), is vital to strengthen the bioethanol production from it. Most studies on bioethanol production from LCB focused on cellulosic fraction only, or very low ethanol productivity is reported from hemicellulosic fraction. The present study investigated a process to convert the hemicellulosic fraction of wheat straw biomass to bioethanol effectively using Scheffersomyces stipitis. This work aimed to develop and demonstrate a systematic approach for scaling up the fermentation process, keeping the volumetric oxygen transfer coefficient (kLa) nearly constant in different scale bioreactors. It was found that 99.11±0.13% of synthetic xylose and 99.04±0.10% of lignocellulosic xylose were converted to bioethanol with a yield and productivity of 0.4706±0.0022 g/g and 1.5325±0.0020 g/Lh; 0.4290±0.0030 g/g and 0.7399±0.0043 g/Lh, respectively at an optimum kLa of 0.5776 (0.5735, 0.5817) min−1 and 0.6924 (0.6887, 0.6961) min−1, respectively in a 0.5 L bioreactor. After that, these optimum kLa were validated in 1 L and 5 L bioreactors. The successful kLa validation revealed that the hemicellulosic fraction of lignocellulosic biomass could also be well utilized for bioethanol production.

A new subjective well-being index using anchored best-worst scaling

Subjective well-being (SWB) describes an individual's life evaluation. Direct elicitation methods for SWB via rating scales do not force individuals to trade-off among life domains, whilst best-worst scaling (BWS) approaches only provide relative measures. This paper instead offers a dual-response BWS task, where respondents nominate areas of most and least importance and satisfaction with respect to 11 SWB domains, whilst also eliciting anchoring points to obtain an absolute measure of domain satisfaction. Combining domain satisfaction and importance produces a robust measure of individual SWB, but statistically unique relative to other life satisfaction measures utilizing single- and multi-item ratings, including global satisfaction and those aggregated over SWB domains, as well as eudemonia. Surveying 2500 Australians reveals anchored-BWS improves discrimination amongst domains in terms of importance and satisfaction, illustrating its value as a diagnostic tool for SWB measurement to focus services, policy, and initiatives in areas to most impact wellbeing. This includes highlighting a major discrepancy between health satisfaction and importance, whilst also reporting that SWB is significantly lower for Indigenous, unemployed, middle-aged, males and lower income groups.

A Multiple Scale Approach to Nonlinear Vibrations and Stability of Doubly Curved Shells/Panels Under External and Parametric Excitations

This study focuses on nonlinear vibrations and stability of doubly curved shells/panels. The thin-walled shell structure is assumed to be acted upon by external loads as well as parametric excitation. Using the first-order shear deformation Fülgge theory assumptions, governing equations of motion are derived for a general doubly curved geometry. Nonlinear components which are compatible with the Von-Karman kinematic assumptions are retained in the formulation and the rest of nonlinear components are neglected due to the fact that strains are assumed to be small and rotations to be moderate. The formulation can be readily reduced to any geometry including cylindrical shells and spherical panels, as benchmark examples in this study. Employing the Galerkin discretization approach and applying a modification to the Volmir assumption, a reduced order form of the original system is determined, which is shown to be a great representative of the original system with much more computational advantages. Using the method of multiple scales, the reduced order nonlinear governing equations are solved to discover the primary resonance, forced vibration characteristics and stability margins of thin-walled shells/panels under the action of parametric excitation. Several interesting findings on nonlinear behavior of cylindrical shells and spherical panels (as benchmark geometries) are presented while giving a demonstration of the accuracy and computational advantages of the proposed model.

Dynamic Data Scaling Techniques for Streaming Machine Learning

This research delves into innovative dynamic data scaling techniques designed for streaming machine learning environments. In the realm of real-time data streams, conventional static scaling methods may encounter challenges in adapting to evolving data distributions. To overcome this hurdle, our study explores dynamic scaling approaches capable of adjusting and optimizing scaling parameters dynamically as the characteristics of incoming data shift over time. The objective is to augment the performance and adaptability of machine learning models in streaming scenarios by ensuring that the scaling process remains responsive to changing patterns in the data. Through empirical evaluations and comparative analyses, the study aims to showcase the efficacy of the proposed dynamic data scaling techniques in enhancing predictive accuracy and sustaining model relevance in dynamic and fast-paced streaming environments. This research contributes to the advancement of scalable and adaptive machine learning methodologies, particularly in applications where timely and accurate insights from streaming data are crucial.

Understanding the reasons why career changers pursue or pass on a STEM teaching career: a Best–Worst Scaling (BWS) approach

AbstractIntractable shortages of science, technology, engineering, and mathematics (STEM) teachers have prompted international policy efforts to recruit career changers to the profession. This research determines the significant influences on career changers’ decisions to pursue or pass on STEM teaching careers. Surveys completed by 91 career changers from Queensland, Australia, were analysed with Best–Worst Scaling (BWS) methods and Margaret Archer’s theories of reflexivity to establish the relative importance of factors influencing career changers’ deliberations on a STEM teaching career. The social impact of teaching was the most influential factor for career changers considering STEM teaching. Career changers who pursued the profession were also influenced by past teaching experiences and feelings towards STEM subjects. Conversely, career changers who decided against STEM teaching indicated their personal traits and life circumstances might not suit a teaching career. These findings offer implications for research and policy aimed at recruiting career changers into STEM teaching careers.

Non-linear vibration and bifurcation analysis of Euler-Bernoulli beam under parametric excitation

This paper presents an analysis of the non-linear vibrations of beams, which play a crucial role in various industrial and construction structures. Understanding the transverse vibrations of beams and accurately determining their frequency response is essential for achieving optimal design and structural performance. The novelty of this study lies in conducting a transverse non-linear vibration analysis of a three-dimensional beam while considering the effect of mid-plane elongation. By incorporating this aspect into the analysis, the study aims to provide deeper insights into the dynamic behavior of beams subjected to non-linear effects. A multiple-time scale approach has been adopted to conduct this research. To verify the accuracy of the method as well as the accuracy of the outcomes gained from this method, a contrast has been made with the 4th-order Runge-Kutta technique, which indicates that the results obtained are acceptable. The frequency response of the beam indicates the presence of a phenomenon of splitting into two non-linear branches during the three-dimensional vibrations of the beam, as well as a hardening state in the frequency response as a result of stretching the middle plane of the beam. Furthermore, a parametric study was conducted in which different parameters were examined to determine the starting point of non-linear bifurcation. As a result, the damping coefficient and resonance deviation parameter are two factors that affect the preference for critical bifurcation over safe bifurcation. Furthermore, the stretching of the middle plane results in a higher non-linear term coefficient in the vibration equations of the beam, which increases the oscillation frequency of the beam.

Development and Validation of a Simple Risk Calculator for Alcohol-Related Adverse Outcomes: Results from a Composite Scale Approach in a Nationally Representative Sample

AbstractWe tested how 5 simple variables, routinely collected in primary care (i.e., the 3 AUDIT-C items, age, and sex), could constitute a clinician-friendly risk calculator tool of the 3-year risk of several alcohol-related adverse outcomes (i.e., alcohol use disorder, withdrawal symptoms, occurrence of tremors or seizures, and alcohol related interpersonal relationship problems, legal problems, and psychological problems) among non-alcohol-dependent individuals consuming alcohol. Data were drawn from a nationally representative sample of US adults, the National Epidemiologic Survey on Alcohol and Related Conditions (wave 1, 2001–2002; wave 2, 2004–2005). We used scaled and rounded composite scoring systems to combine information derived from these predictors and quantify the risks for each subject. Analyses were limited to 16,710 respondents without a lifetime history of alcohol use disorder who completed both interviews and had consumed alcohol during the year prior to wave 1 (development sample N = 8355, validation sample N = 8355). The risk equations calibrated well (Hosmer and Lemeshow test p values ≥ 0.072) and showed good predictive values (C indices ranging from 0.727 to 0.872) in the validation sample. This risk calculator can be clinically useful in primary care for identification of at-risk individuals, encourage respondents to reduce their drinking, and improve prevention.

Integration of vorticity–velocity formulation in a lattice Boltzmann method for porous media

A lattice Boltzmann method (LBM) is proposed to address the two-dimensional macroscopic equations of velocity–vorticity for porous media in incompressible flows. The macroscopic equations of two-dimensional porous media using the representative element volume scale approach, employing various models, are shown. The momentum equations are transformed and presented in the velocity and vorticity format. Additionally, the energy and concentration equations are thoroughly examined. Subsequently, the LBM is presented to restore the dimensional macroscopic equations of the velocity–vorticity format for various porous models, accounting for external forces. The paper provides proof and derivations of the equations for the LBM, which are then demonstrated and discussed. The suggested approach is evaluated across a variety of well-established benchmark examples within the realm of fluid flow, heat, and mass transfer in porous media. Importantly, the LBM approach significantly reduces computational time compared to previous methods in the field by eliminating pressure in the momentum equation, thereby reducing the number of unknown variables and transforming the equation into a convection–diffusion form. This modification leads to a linear equilibrium distribution function and a noteworthy decrease in computational costs.