Three-level Hierarchical Structure Research Articles

Indirect 3D printing CDHA scaffolds with hierarchical porous structure to promote osteoinductivity and bone regeneration

Hierarchical porous structure, which include macropores, minor pores, and micropores in scaffolds, are essential in the multiple biological functions of bone repair and regeneration. In this study, patient-customized calcium-deficient hydroxyapatite (CDHA) scaffolds with three-level hierarchical porous structure were fabricated by indirect 3D printing technology and particulate leaching method. The sacrificial template scaffolds were fabricated using a photo-curing 3D printer, which provided a prerequisite for the integral structure and interconnected macropores of CDHA scaffolds. Additionally, 20 wt% pore former was incorporated into the slurry to enhance the content of smaller pores within the CDHA-2 scaffolds, and then the CDHA-2 scaffolds were sintered to remove the sacrificial template scaffolds and pore former. The obtained CDHA-2 scaffolds exhibited interconnected macropores (300–400 μm), minor pores (∼10–100 μm), and micropores (< 10 μm) distributed throughout the scaffolds, which could promote bone tissue ingrowth, increase surface roughness, and enhance protein adsorption of scaffolds. In vitro studies identified that CDHA-2 scaffolds had nanocrystal grains, high specific surface area, and outstanding protein adsorption capacity, which could provide a microenvironment for cell adhesion, spreading, and proliferation. In addition, the murine intramuscular implantation experiment suggested that CDHA-2 scaffolds exhibited excellent osteoinductivity and were superior to traditional BCP ceramics under conditions without the addition of live cells and exogenous growth factors. The rabbit calvarial defect repair results indicated that CDHA-2 scaffolds could enhance in situ bone regeneration. In conclusion, these findings demonstrated that the hierarchical porous structure of CDHA scaffolds was a pivotal factor in modulating osteoinductivity and bone regeneration, and CDHA-2 scaffolds were potential candidates for bone regeneration.

Numerical and experimental investigation of the dynamic mechanical behavior of precipitation-strengthed NiCoCrSi0.3C0.048 medium-entropy alloy

An extended crystal plasticity model and an optimized neural network are established to investigate the mechanical behavior of CoCrNiSi0.3C0.048 Medium entropy alloy (MEA) with a three-level hierarchical precipitation structure under dynamic compressive deformation at a variety of ranges of strain rates. The interaction between the matrix and first-level precipitates is described by a presented hybrid representative volume element RVE model, involving the effects of volume fraction (Vf), radius and geometric distribution on heterogeneous deformation. Effects of second- and third-level precipitates are realized through the extended crystal plasticity constitutive model, reflecting the motion mechanism of dislocations near the precipitates in the form of initial slip resistance. Meanwhile, this study investigates the influence of the presence of primary precipitates on the initiation of slip systems within special grains with Goss or S orientations in the matrix. Additionally, it provides a more in-depth explanation of the underlying principles behind the suppression of Goss texture formation by the precipitates from the perspective of slip systems analysis. The changing of volume fractions affects flow stress evolution. Avoiding suffering from expensive computational consumption by the crystal plasticity finite element method, an artificial neural network model optimized through a genetic algorithm, is presented to predict stress-strain responses and texture evolution results under varying compression strain rates. A reliable dataset derived from crystal plasticity finite element models and experimental results is utilized to train, test, and validate the genetic algorithm-based artificial neural network model. This model demonstrates good prediction capability in dynamic mechanical behavior and texture evolution, showcasing the feasibility and efficacy of the proposed neural network model. Compared to the CPFEM method, neural network models can greatly improve computational efficiency.

Statistical Power Analysis for Univariate Meta-Analysis: A Three-Level Model

This study extends prior work on power analysis in two-level meta-analysis and provides methods on power analysis for univariate three-level meta-analysis. In a three-level hierarchical structure effect sizes are nested within studies, which in turn are nested within research groups of investigators. Consequently, the three-level model takes into account the between-study (second level) and the between-research group (third level) variances. The study provides closed form equations to compute the prospective statistical power of the z-test of the combined weighted average effect size. Illustrative examples that demonstrate the applicability of the methods in prospective power analysis are provided. Moreover, a simulation study is also conducted to demonstrate how prospective statistical power is modified by changes of the values of the design parameters that impact power within the context of the three-level model. Results indicate the third-level variance is inversely related with statistical power in three-level meta-analysis.

О вариативно-модульном характере современной социально-практической философии

The article deals with the topical issue of creating a variation-modular system of practical worldview. This topic of modern socio-practical philosophy acquires particular importance in the extreme conditions of estabishing a new geopolitical architecture and the forced reduction of personal and public freedom in the Russian society. The socio-evolutionary approach, supplemented by the author’s model of ten degrees of freedom as independence, as well as the institutional-matrix approach which assumes a three-level hierarchical structure of human consciousness, in which the module of religious and metaphysical meaning-making and moral goal-setting play a determining role, are used as methodological foundations of the alternative worldview system. The variation-modular nature of practical philosophy allows us to successfully adapt to rapidly changing conditions of life, while preserving the basic structure of moral-legal principles (do not kill, do not lie, do not steal) based on the practical postulate – “I am always free to a certain extent”, i.e. the idea of matching personal responsibility of man with a real degree of his freedom. For a person in an extreme situation, social and practical philosophy offers an opportunity to construct his own worldview system, which allows him to adapt effectively to various crisis situations and at the same time to preserve the potential for further progress to higher degrees of freedom – political, moral and religious and creative. The worldview variability is considered in this article as a necessary way of constructive adaptation in the conditions of the global information struggle – “when everybody lies”, and when it is necessary to assert one’s per-sonal interests and values or autonomy in order to preserve the moral and practical prospect of being worthy of a happy life.

MANAGEMENT MODEL OF CORPORATE TRADE SYSTEM

The purpose of the article is to develop a model for managing a corporate trading system and define the principles that ensure its use. Methodology. The research methodology is based on the dialectical and systemic approach, i.e., the activities of the components of the business system are considered in their interconnection and interdependence. The methods of multidimensional logic, formalisation, structural synthesis, modelling and scientific generalisation are used to develop the management model of the business system. Results. The evolution of the business trading system reflects changes in space and time. It is impossible to change the scale of its activities without introducing managerial and organisational innovations. Corporate management is based on a three-level hierarchical structure: shareholders, board of directors and top management. The effectiveness of corporate management in commerce is determined by the degree of centralisation of management decisions. Corporate management and its senior executives ensure the achievement of the system's objectives, control and plan its development. A unified strategic management centre carries out strategic management of business units and internal coordination of actions, change management, while at the same time giving them the right to independent operational management. Separation of strategic and operational management subsystems allows to create a management system combining strategic objectives and performance parameters. Practical implications. The practical results can serve as a basis for further research on ways to improve the strategic and operational management of business units that are part of the corporate trading system, taking into account changes in the internal and external environment. Value/Originality. The proposed model of corporate trading system management allows to better understand the essence of the management process, provides strategic management of their activities from a single strategic management centre and gives the right to independent operational management.

Multi-channel distribution in the banking sector and the branch network restructuring

European banking groups have been addressing the problem of restructuring their branch networks. Indeed, in the light of the recent digital transition of services, they aim to leverage digital channels to deliver basic services and reduce the number of physical facilities to dedicate to more complex and added-value operations. In order to implement the new business model, banking groups are shrinking their internal branch networks and outsourcing basic services to maintain physical proximity to customers unwilling to adopt digital channels. This work aims to formulate a mathematical programming model to support the decision-making process concerning the branch network restructuring. The model is formulated as a hierarchical covering location problem. Three types of branches providing different categories of services are considered. They are organized according to a three-level hierarchical structure, and each level is associated with a covering radius, representing the related accessibility condition to be guaranteed to users. A further category of facilities is considered, namely external facilities, that may support internal ones in providing basic banking services. The objective is to identify the network structure able to serve all the demand for banking services and minimize the total costs. A specific parameter is introduced to regulate the maximum outsourcing level that the bank is willing to achieve. The model is tested by considering a real case study concerning one of the main banking groups in Italy. The obtained results show the capability of the model to provide interesting scenarios and fruitful managerial implications.

Machine learning-based early diagnosis of autism according to eye movements of real and artificial faces scanning.

Studies on eye movements found that children with autism spectrum disorder (ASD) had abnormal gaze behavior to social stimuli. The current study aimed to investigate whether their eye movement patterns in relation to cartoon characters or real people could be useful in identifying ASD children. Eye-tracking tests based on videos of cartoon characters and real people were performed for ASD and typically developing (TD) children aged between 12 and 60 months. A three-level hierarchical structure including participants, events, and areas of interest was used to arrange the data obtained from eye-tracking tests. Random forest was adopted as the feature selection tool and classifier, and the flattened vectors and diagnostic information were used as features and labels. A logistic regression was used to evaluate the impact of the most important features. A total of 161 children (117 ASD and 44 TD) with a mean age of 39.70 ± 12.27 months were recruited. The overall accuracy, precision, and recall of the model were 0.73, 0.73, and 0.75, respectively. Attention to human-related elements was positively related to the diagnosis of ASD, while fixation time for cartoons was negatively related to the diagnosis. Using eye-tracking techniques with machine learning algorithms might be promising for identifying ASD. The value of artificial faces, such as cartoon characters, in the field of ASD diagnosis and intervention is worth further exploring.

Hierarchical precipitates facilitate the excellent strength-ductility synergy in a CoCrNi-based medium-entropy alloy

An interstitial carbon-doped CoCrNiSi0.3 medium-entropy alloy (MEA) has been developed, which exhibits excellent strength-ductility synergy. This has been achieved through the implementation of a three-level hierarchical-precipitate-microstructure design. The CoCrNiSi0.3C0.048 MEA displays an ultra-high yield strength of 1.34 GPa, accompanied by a uniform tensile elongation of 8.62%, surpassing the performance of most carbon/silicon-doped MEAs. The three-level hierarchical precipitate structure comprises the primary Cr23C6 carbides (2–10 μm), the secondary SiC precipitates (200–500 nm) surrounding the grain boundaries, and the tertiary SiC precipitates (∼50 nm) within the grains. The strengthening and toughening behavior of the current MEAs are attributed to multiple mechanisms, including crack branching and blunting in Cr23C6 carbides, dislocation-bypass mechanism around the non-shearable SiC precipitates, hetero-deformation-induced strengthening caused by the interface between matrix/three-level hierarchical precipitates, as well as stacking-fault networks and dense nanotwins activated by precipitates in the matrix. These findings provide valuable insights into the development of high-performance alloys for engineering applications in the future.

Condition index for public toilets using multi-criteria decision-making techniques

Maintaining public toilets in good condition is essential for public health. Lack of maintenance may render them inefficient and unusable. Overall knowledge of the condition of toilets and prioritising maintenance activities are crucial for optimal enhancement and maintenance. A condition index helps to evaluate the facilities in toilets and categorise toilets based on their condition. To achieve this, a three-level hierarchical structure was developed from the literature search to identify factors and their attributes related to the condition of toilets. Then, a hierarchy process was used to estimate the weights of the factors and their attributes based on expert opinions. Finally, a weighted-sum method was used to develop an index. The developed index was applied to 40 randomly selected public toilet facilities to check the sensitivity of the index to changes in weighting and attributes.

Evaluation of Power Grid Investment Decision-Making with Mixed Binomial Coefficient and Coefficient of Variation

The investment evaluation of power grid construction projects is a necessary link for power grid companies to carry out power grid construction. In the traditional evaluation process, it is generally based on the original index scores or similar schemes for comparison and decision-making. There are problems of simple methods and insufficient theoretical support. Fully considering various factors in the investment process of power grid construction, a set of rating index system with three-level hierarchical structure is constructed with actual demand as the standard. The evaluation model is verified and analyzed by an example.

Priority Areas of Scientific and Technological Development

The accelerated scientific and technological development of Russia requires the development of both platform (end-to-end) technologies with significant multiplicative potential and targeted areas that form the basis of the Russian economy and are focused on solving the most important socio-economic problems. Accounting for the effects of global trends, combined with the expected demand for new technologies from the sectors of the economy, made it possible to form promising areas of scientific and technological development, which are presented in the report in the form of a three-level hierarchical structure.

Non-pharmaceutical interventions in response to the COVID-19 pandemic in 30 European countries: the ECDC-JRC Response Measures Database.

In response to the COVID-19 pandemic, the European Union/European Economic Area (EU/EEA) countries implemented a wide set of non-pharmaceutical interventions (NPIs), sometimes with limited knowledge on their effect and impact on population. The European Centre for Disease Prevention and Control (ECDC) and the European Commission’s Joint Research Centre (JRC) developed a Response Measures Database (ECDC–JRC RMD) to archive NPIs in 30 EU/EEA countries from 1 January 2020 to 30 September 2022. We aimed to introduce a tool for the wider scientific community to assess COVID-19 NPIs effect and impact in the EU/EEA. We give an overview of the ECDC–JRC RMD rationale and structure, including a brief analysis of the main NPIs applied in 2020, before the roll-out of the COVID-19 vaccination campaigns. The ECDC–JRC RMD organises NPIs through a three-level hierarchical structure and uses four additional parameters (‘status’, ‘implementation’, ‘target group’ and ‘geographical representation’) to provide further information on the implementation of each measure. Features including the ready-for-analysis, downloadable format and its agile taxonomy and structure highlight the potential of the ECDC–JRC RMD to facilitate further NPI analysis and optimise decision making on public health response policies.

The multiscale meso-mechanics model of viscoelastic cortical bone.

Cortical bone is a complex hierarchical structure consisting of biological fiber composites with transversely isotropic constituents, whose microstructures deserve extensive study to understand the mechanism of living organisms and explore development of biomimetic materials. Based on this, we establish a three-level hierarchical structure from microscale to macroscale and propose a multiscale micromechanics model of cortical bone, which considers Haversian canal, osteonal lamellae, cement line and interstitial lamellae. In order to study the microstructural effect on the elastic behavior of hierarchical structures, the Mori-Tanaka model and locally exact homogenization theory are introduced for the homogenization of heterogeneous materials of microstructure at each level. Within sub-microscale, Haversian canal and Osteonal lamella are treated as fiber and matrix, whose homogenization is surrounded with cement line matrix in microstructure (or what we called "osteon") for the second homogenization; finally, osteon and interstitial lamella establish the meso-structure for the third homogenization, predicting the effective moduli of cortical bone. The correctness of the model in this paper is verified against the data in literature with good agreement. Finally, the dynamic viscoelastic response of cortical bones is investigated from a multiscale perspective, where the measured data are substituted into the present models to study the hydration and aging effect on bones' stiffness and viscoelasticity. It is demonstrated that the hydration is much more influential in affecting the storage and loss moduli of cortical bone than the aging effect. We also present a few numerical investigations on microstructural material and geometric parameters on the overall mechanical properties of cortical bone.

Factors Evaluating the Crisis Preparedness of a City in the Era of New Normal: Based on an Analytic Hierarchy Process Survey of Korean Experts

This study aimed to identify the key components of crisis preparedness and understand the relative importance of various public relations (PR) factors to suggest efficient ways to prepare for a pandemic crisis, such as COVID-19. We highlight the processoriented approach of crisis preparedness in addition to the static readiness in response to a crisis. Specifically, we conducted an analytic hierarchy process (AHP) using focus group interviews and a pairwise comparison questionnaire with 25 PR experts from academia, industry, and local governments. The experts highlighted a three-level hierarchical structure of crisis preparedness. At the highest level, issue management (43.3%) was relatively more important than crisis communication (30.4%) and risk communication (26.3%). Overall, we observed that process-oriented crisis preparedness (e.g., monitoring issues, building positive and resolving negative issues, and reporting crisis) are relatively more important than the static preparedness system (e.g., budgets and printing periodicals, or classic offline PR tactics such as communication with different stakeholders and interest groups). Overall, we highlight the importance of pre-crisis readiness over post-crisis readiness, preemptive PR over typical offline PR activities, and intangible trust-building based on systematic information monitoring.

Development of hardware and software support of computer-integrated technology of complex of secondary condensation of ammonia production

The object of research is the technological complex of secondary condensation (TCSC) and the control system of a typical ammonia synthesis unit of the AM-1360 series. The analysis of the conditions of its functioning and hardware and technological design was carried out. The coordinates of the control vector are determined. The features of the proposed functional diagram and the necessary algorithmic software for the computer-integrated control technology of the TCSC with a correction subsystem for decision-making under uncertainty are established. The implementation of the proposed solutions is complicated by the use of the information and control complex TDC-300 (USA) with closed-type software installed on the existing ammonia synthesis units. The need for such a control complex to implement a decision-making subsystem under conditions of uncertainty is shown to supplement the existing control system with hardware and software of an «open» type. A computer-integrated TCSC technology based on a three-level hierarchical structure has been created. The implementation of the zero and first levels of such a structure form single software and hardware complex consisting of a programmable logic controller and an automated operator's workplace based on an industrial computer with installed software. A software implementation of decision-making on the correction of the coordinates of the control vector by additional hardware and software based on the VIPA logic controller and the Zenon SCADA system was made. A scheme of network information flows has been implemented, which illustrates the functioning of the decision-making correction subsystem in the general structure of the TCSC computer-integrated control technology. Implementation of the developed system allows, under the existing uncertainties, to reduce the secondary condensation temperature by an average of 3 °C, which ensures an annual reduction in natural gas consumption by 1 million nm3. The proposed approach to the possibility of combining «open» and «closed» type hardware and software can be applied in other industries.

Superhydrophobic SLA 3D printed materials modified with nanoparticles biomimicking the hierarchical structure of a rice leaf

ABSTRACT The rice leaf, combining the surface properties of lotus leaves and shark skin, presents outstanding superhydrophobic properties motivating its biomimesis. We created a novel biomimetic rice-leaf superhydrophobic surface by a three-level hierarchical structure, using for a first time stereolithographic (SLA) 3D printed channels (100µm width) with an intrinsic roughness from the printing filaments (10µm), and coated with TiO2 nanoparticles (22 and 100nm). This structure presents a maximum advancing contact angle of 165° characterized by lower both anisotropy and hysteresis contact angles than other 3D printed surfaces, due to the presence of air pockets at the surface/water interface (Cassie-Baxter state). Dynamic water-drop tests show that the biomimetic surface presents self-cleaning, which is reduced under UV-A irradiation. The biomimetic surface further renders an increased floatability to 3D printed objects meaning a drag-reduction due to reduced water/solid contact area. Numerical simulations of a channel with a biomimetic wall confirm that the presence of air is essential to understand our results since it increases the average velocity and decreases the friction factor due to the presence of a wall-slip velocity. Our findings show that SLA 3D printing is an appropriate approach to develop biomimetic superhydrophobic surfaces for future applications in anti-fouling and drag-reduction devices.

Liquidity: the genesis of the concept, structure and its role in the financial relations of economic entities

The aim of this article is to provide a theoretical definition of the financial aspect of liquidity of enterprises, to improve the classification of the types of liquidity and determine its functions. The subject of the study is to consider the problematic issues of classification of the types of liquidity, which are manifested in the object or subject in the form of a three-level hierarchical structure at the macro- and micro levels of management and the interconnections between them. The theoretical foundations of financial and economic categories of "liquidity" are presented in the works of A. Marshall, A. Montchrestien, W. Petty, A. Smith, W. Stafford and others. J Keynes and K. Marx made a significant contribution to the development of this theory. At the present stage of consideration the enterprises liquidity, the works of many Ukrainian and foreign economists are devoted: S. Brue, S. Myers, K. McConnell, I. Fischer, M. Friedman, J. Hicks, P. Laiko, L. Lakhtionova, E. Nikbacht and A. Gropelli, A. Podderyogin, G. Savitskaya and others. However, these issues have not been sufficiently investigated in the published scientific works. Financial stability is the basis of every enterprise in a market economy. In this process, the priority is to ensure its liquidity. Many scientific works of both foreign and Ukfainian scientists are devoted to the study of various aspects of liquidity. However, so far there is no clearly defined system of theoretical conclusions on the assessment of the enterprises liquidity. Remains undisclosed or debatable questions about the place and role of liquidity in the financial management of the enterprise, the classification of its types needs to be improved. This has a negative impact on the possibilities for efficient liquidity management. Therefore, the problem of ensuring liquidity in a market economy remains relevant.

Impact of different platform promotions on online sales and conversion rate: The role of business model and product line length

Facing fierce competition, e-commerce platforms are implementing various promotional strategies to attract consumers. Based on real-world transaction data from the largest online retailer in China, JD.com, this study builds a three-level hierarchical promotion structure and evaluates the impact of different platform promotions on sales and conversion rate. We find that monetary promotions have a stronger impact on sales than gift promotions. Among monetary promotions, standard promotions are more influential than coupon promotions. And among standard promotions, direct and quantity promotions are more effective than bundle promotions. Moreover, we find that the platforms' business model (i.e., reseller or marketplace) and product line length have significant moderating effects on the impact of quantity promotions on both sales and the conversion rate, while the moderating effects on direct promotions are only observed on its impact on sales. Our findings offer guidelines for e-commerce platforms to implement efficient promotion strategies to improve their performance by generating online consumer purchase intention and behavior based on the business model and product line length.

Suitable site selection for transfer stations in a solid waste management system using analytical hierarchy process as a multi-criteria decision analysis: a case study in Azuay-Ecuador

To guarantee a dignified life in low-incoming countries where socio-environmental negative implications derived from the municipal solid waste (MSW) by its excessive generation, lack of governance, and financial resources, sustainable and integrated solutions are required. From this perspective, well-located transfer stations (TSs) are conceived as an alternative to improve MSW management quality in municipalities that generate little MSW and have long transportation distances. Consequently, this research aims to find optimum areas to locate TSs in the province of Azuay-Ecuador as a commonwealth proposal. It applies a multi-criteria decision analysis based on geographic information systems with the analytical hierarchical process technique: a heuristic and scalable method that simultaneously evaluates subjective and non-monetized inputs. The authors faced it from a holistic perspective in a three-level hierarchical structure; starting from categories: technical, environmental, economic, and social; then criteria: rivers, protected areas, populated areas, land use, educational centers, health centers, tourist sites, basic services, roads, gravity centers, geology, power grid, and slopes; and finally, sub-criteria defined by criteria´s measurable attributes. This research provides local decision-makers with middle-scale tools and a first diagnosis to focus later efforts in local studios over potential sites. The results showed that 79.12% of the study area was restrictive to place a TS. The remaining territory suitability index values between 13 and 89% were found, with possible TSs at Paute, Sigsig, and Nabón to serve nine from fifteen cantons.

Application of MHE-based NMPC on a Rotary Tablet Press under Plant-Model Mismatch

Active control strategies play a vital role in modern pharmaceutical manufacturing. Automation and digitalization are revolutionizing the pharmaceutical industry and are particularly important in the shift from batch operations to continuous operation. Active control strategies provide real-time corrective actions when departures from quality targets are detected or even predicted. Under the concept of Quality-by-Control (QbC), a three-level hierarchical control structure can be applied to achieve effective setpoint tracking and disturbance rejection in the tablet manufacturing process through the development and implementation of a moving horizon estimation-based nonlinear model predictive control (MHE-NMPC) framework. When MHE is coupled with NMPC, historical data in the past time window together with real-time data from the sensor network enable model parameter updating and control. The adaptive model in the NMPC strategy compensates for process uncertainties, further reducing plant-model mismatch effects. The frequency and constraints of parameter updating in the MHE window should be determined cautiously to maintain control robustness when sensor measurements are degraded or unavailable. The practical applicability of the proposed MHE-NMPC framework is demonstrated via using a commercial scale tablet press, Natoli NP-400, to control tablet properties, where the nonlinear mechanistic models used in the framework can predict the essential powder properties and provide physical interpretations.