Theoretical Statements Research Articles

Identification of Boundary Conditions in a Spherical Heat Conduction Transmission Problem

Although numerous analytical and numerical methods have been developed for inverse heat conduction problems in single-layer materials, few methods address such problems in composite materials. The following paper studies inverse interface problems with unknown boundary conditions by using interior point observations for heat equations with spherical symmetry. The zero degeneracy at the left interval 0<r<R1 leads to solution difficulties in the one-dimensional interface problem. So, we first investigate the well-posedness of the direct (forward) problem in special weighted Sobolev spaces. Then, we formulate three groups of unknown boundary conditions and inverse problems upon internal point measurements for the heat equation with spherical symmetry. Second-order finite difference scheme approaches for direct and inverse problems are developed. Computational test examples illustrate the theoretical statements proposed.

The Humanbecoming Concept Inventing Model: Another Exploration of Hope.

In this paper, a community of eight aspiring Parse scholars presents experiences with a scholarly investigation using Parse's humanbecoming concept inventing model to discover the meaning of the nursing phenomenon hope as a universal humanuniverse living experience. The now-truth of the universal humanuniverse living experience hope surfaced as envisioning possibilities with sureness-unsureness arising with opportunities-restrictions. The ingenuous proclamation of hope, together with the aspiring Parse scholars' chosen artform, is declared as a theoretical statement at the level of the humanbecoming paradigm is imaging the originating of enabling-limiting. The contributions of aspiring Parse scholars offer opportunities to advance nursing knowledge of the universal humanuniverse living experience hope.

Coordination of a socially responsible two-stage supply chain under random yield and demand

This study integrates corporate social responsibility (CSR) and channel coordination in a supply chain (SC) under random yield and random demand. In the SC, a supplier with random yield determines wholesale price and production input, and a producer with CSR decides order quantity and CSR investment facing CSR-related random demand. For centralized SCs with and without CSR, we prove the unimodality of the expected profits of the SCs for generic random yield and demand, and show the uniqueness of optimal ratio of order quantity to production input quantity. We disclose that the optimal expected profit of the SC with CSR is larger than that of the SC without CSR, and the profit difference increases with CSR effort and expected yield. We also find that the optimal CSR investment increases with the expected yield. Subsequently, the Nash equilibrium solutions of decentralized SCs under wholesale price and revenue-sharing contracts are analyzed. Next, we present a revenue and CSR sharing contract to realize channel coordination and win-win of SC members and related stakeholders. Lastly, we verify theoretical statements of centralized and decentralized SCs versus three numerical examples, and present managerial insights for the effect of yield uncertainty and CSR effort.

Magnetic field of electrical heating cable systems of the floors for residential premises

Problem. In order to effectively protect public health from the magnetic field of electric heating cable systems of the floors, it is necessary to reduce it to a safe level. However, this requires careful study of the magnetic field. The purpose of the work is to develop a mathematical model and a verified methodology for calculating the magnetic field of electric heating cable systems of the floors in residential premises, and assessment of compliance of the magnetic field with the normative level. Method. A methodology for calculating the magnetic field of electric heating cable systems of the floors in residential premises has been developed. Scientific novelty. Based on Bio-Savar’s law and the principle of superposition, an analytical model of the magnetic field of electric heating cable systems of the floors and its calculation method was created. The magnetic field of the coaxial heating cable is determined, taking into account the value of its maximum eccentricity. The experimentally substantiated correctness of the obtained theoretical statements, which is confirmed by their coincidence with the results of the experiment with a spread of less than 7 %. Practical significance. A verified methodology for calculating the magnetic field of electric heating cable systems of the floors was proposed and an assessment of compliance of their magnetic flux density with the normative level of 0.5 μT was performed. It is recommended to lay modern two-wire heating cables at a depth of at least 75–100 mm from the floor. With a smaller laying depth, it is recommended to use coaxial heating cables, which have an order of magnitude smaller magnetic field. References 51, tables 1, figures 11.

A variable‐step high‐order scheme for time‐fractional advection‐diffusion equation with mixed derivatives

AbstractWe consider a high accuracy numerical scheme for solving the two‐dimensional time‐fractional advection‐diffusion equation including mixed derivatives, where the variable‐step Alikhanov formula and a fourth‐order compact approximation are employed to time and space derivatives, respectively. Under mild assumptions on the time step‐sizes, we obtain the unconditional stability and high‐order convergence (second‐order in time and fourth‐order in space) of the proposed scheme by energy method. The theoretical statements are justified by the numerical experiments.

Variable-step [formula omitted] method combined with time two-grid algorithm for multi-singularity problems arising from two-dimensional nonlinear delay fractional equations

In this paper, we focus on the numerical simulation for two-dimensional nonlinear fractional sub-diffusion equations in the presence of time delay. Firstly, we investigate the existence, uniqueness and regularity of the solution for such problems. The theoretical result implies that the solution at τ+ is smoother than that at 0+, where τ is a constant time delay, and this is an improvement for the work (Tan et al., 2022). Secondly, a high-order difference scheme based on L1 method is constructed. For the sake of repairing the convergence order in temporal direction and improving the computational efficiency, an efficient time two-grid algorithm based on nonuniform meshes is first developed. The convergence order of the two-grid scheme reaches O(NF−min{rα,2−α}+NC−min{2rα,4−2α}+h12+h22), where NF and NC represent the number of the fine and coarse grids respectively, while h1 and h2 are the space-step sizes. Furthermore, stability and convergence analysis of the proposed scheme are carefully verified by energy method. Finally, numerical experiments are carried out to show the validity of theoretical statements.

ON THE PROPERTIES OF A FAST ALGORITHM FOR SOLVING A THREE-DIMENSIONAL INVERSE PROBLEM OF SCALAR ACOUSTICS

t Theinverse single-frequency problem of scalar acoustics in three-dimensional space is considered. It consists in determining the characteristics of acoustic inhomogeneities lying in a flat layer from the distribution of the complex amplitude of the acoustic field in a flat recording layer. To effectively solve it, a special numerical algorithm is used, previously proposed and justified by the authors. As its component part, the algorithm uses solutions to special one-dimensional Fredholm equations of the 1st kind, and in the case of ambiguity in the solution of the latter, their normal solutions (solutions with a minimum norm) are sought. To regularize this ill-posed inverse problem, Tikhonov regularization and the TSVD method are used. A systematic numerical study is carried out of the influence of various parameters in the data recording scheme on the accuracy of the approximate solutions obtained using the algorithm. In particular, we study the dependence of this accuracy on the position of point sources and composite sources that cause sound vibrations, its dependence on the position of the data recording layer, and on the number of planes in which the recording sensors lie. It is shown that acceptable accuracy of approximate solutions can be obtained even with two such layers. In addition, an approach to the numerical study of the ambiguity of the solution to the inverse problem under consideration is proposed. It is based on special theoretical statements given in the article, and on the same numerical algorithm for solving the inverse problem. The approach is focused on comparing several normal solutions of one-dimensional integral equations from the problem under consideration. These normal solutions are calculated with respect to various elements. An example of using this theory to numerically estimate the non-uniqueness of a solution is given.

Relational Quantum Mechanics: Ozawa’s Intersubjectivity Theorem as Justification of the Postulate on Internally Consistent Descriptions

The Ozawa’s intersubjectivity theorem (OIT) proved within quantum measurement theory supports the new postulate of relational quantum mechanics (RQM), the postulate on internally consistent descriptions. But from OIT viewpoint postulate’s formulation should be completed by the assumption of probability reproducibility. We remark that this postulate was proposed only recently to resolve the problem of intersubjectivity of information in RQM. In contrast to RQM for which OIT is a supporting theoretical statement, QBism is challenged by OIT.

A second-order fitted scheme combined with time two-grid technique for two-dimensional nonlinear time fractional telegraph equations involving initial singularity

In this paper, we derive the improved regularity for two-dimensional nonlinear time fractional telegraph equations by virtue of the technic of decomposition at first. Then, the famous L2-1σ formula is adopted to approximate the Caputo derivative and the central finite difference method is used for spatial discretization. The convergence accuracy of the proposed method is second order in both temporal and spatial direction. Meanwhile, for the sake of reducing the time of solving the high dimensional nonlinear problems, an efficient time two-grid algorithm is proposed. Furthermore, stability analysis of the proposed scheme is studied by the energy method. At last, numerical experiments are presented to verify the validity of the theoretical statements.

Advancing Nursing Science: Deriving a Middle-Range Theory for System-Level Communication Research in Complex Hospital Environments.

Background: Millions of injuries and deaths occur yearly from preventable errors, despite interventions applied at the point of care. Although evidence suggests that system-level factors are responsible for hospital system health and patient safety, research has largely not accounted for hospital complexity. Prior to the authors' research regarding the communication of system-level events that influence hospital system health and patient safety, no nursing-specific communication theories that accounted for hospital complexity were identified. However, theory-guided research holds the potential to boost scientific knowledge through the provision of a robust foundational understanding of phenomena. Purpose: The purpose of this article is to discuss the concept derivation used to create a middle-range theory for the guidance of research involving system-level communication in complex healthcare environments as it relates to hospital system health and patient safety. Methods: Concept derivation as described by Walker and Avant (2018) was conducted using parent concepts from the Effective Nurse-to-Nurse Communication Framework, Symbolic Interactionism, Information Theory, Gerbner's Communication Model, and Complexity Theory. Results: Authentication of the derived Effective System-to-System Communication Theory (ESSCT) was confirmed through identification of coherent relationships between the concepts and conceptual statements, alignment with the nursing metaparadigm, and peer review by a subject matter expert from the nursing discipline. Additionally, research revealed an overall congruency between the research findings and the ESSCT's theoretical statements. Implications: The current healthcare climate necessitates that research involving communication be optimized by a germane theoretical underpinning that accounts for hospital complexity. The authors contend that the use of the derived theory may assist such endeavors.

The Humanbecoming Concept Inventing Model: Feeling Sad.

In this paper, the scholar explored the universal humanuniverse living experience of feeling sad with the humanbecoming concept inventing model. The now-truth of feeling sad is penetrating discomfort arising with contemplating joy-sorrow of affiliations amid envisioning new possibilities. The theoretical statement as the ingenuous proclamation of feeling sad is imaging the connecting-separating of transforming with the scholar's chosen artform, Melancholy by Albert Gyorgy. The scholar aimed to advance nursing knowledge of the universal humanuniverse living experience of feeling sad.

MONITORING RESEARCH IN THE SYSTEM OF SOCIAL COMMUNICATION SCIENCES

The article interprets and systematizes the idea of monitoring as a research method in the field of social communication sciences for the solution of traditional issues of journalism science and outlines the prospects of its application in view of the current issues of media science, which introduce into the research field the latest trends in the development of the mass media system at the current stage of deployment information society. The scientific value of monitoring as a research method is inseparable from its ability to see mass media as a complex heterogeneous system object and to ensure systematicity (complexity of vision, comparability of data, consistency of aspects of object analysis) of observations of this object at its different levels and in different sections. It is also important to be aware of the need to see the background as a theoretical basis for interpreting monitoring data. Self-sufficient, self-valued empirical monitoring studies of mass media activity can be good material for larger research projects, which demonstrates the high research potential of the monitoring method. Monitoring studies of mass media is the accumulation of empirical material for large-scale research projects in the field of social communications of both synchronic and diachronic type. However, only qualitative data from monitoring studies can be adequately used in the future and productively included in large-scale scientific projects, where comparison of data, combination of disparate empirical material with other analytical data is expected. Monitoring studies of mass media is a perspective of using the accumulation of empirical material for media critical studies and providing recommendations and practical advice for the implementation of mass media activities of editorial teams. This is the potential of monitoring research in the aspect of management decisions in the mass media system. The latest media phenomena that are of research interest, but have not yet entered the science of social communications as an object and subject of scientific understanding, with clearly defined parameters, are probably promising material for monitoring observations. This is a question of understanding the potential of the monitoring method in its application to the newest media phenomena that are significantly transforming the sphere of mass communication activity. Among the media phenomena that can become material for monitoring studies, the author of the article sees, first of all, such notable and influential phenomena as constructive journalism (journalism of solutions) and brand journalism. Monitoring provides an opportunity to verify, through the observation of extensive empirical material, the theoretical statements of scientists regarding the requirements for constructive journalism and brand journalism, which are formulated on the basis of the construction of a conceptual model of this type of mass media work. Thanks to monitoring, it is possible to study constructive journalism and brand journalism in terms of their use of forms of information submission, the specifics of addressing narrow target segments of the mass audience, technologies for retaining the recipient’s attention, etc. The data obtained during the monitoring can be used in a comparative study in the future, which can significantly expand the understanding of modern science about the latest media phenomena, which are still difficult to fit into the limits of scientific interpretations. If we see the latest trends and phenomena in the mass communication environment as indicators of transformations and look for factors of significant changes and shifts in social communication activity, then monitoring as a research method can be extremely useful and promising in understanding changes in the mass media system.

The Kripkean explanation of aposteriori necessity: in the case of identity statements about chemical substances

ABSTRACT In the addenda to his Naming and Necessity, Kripke provides an account of how necessary aposteriori statements are possible. In such a case, there is an apriori general principle telling us that it is necessary if true at all. Though straightforward in its broad compass, this account faces two obvious questions in its application: in each case of necessary aposteriori statements, what is the underlying principle and how is it established apriori? I treat these questions with respect to theoretical identity statements concerning chemical substances, such as ‘water is H 2 O ’. I argue that the general principle underlying the necessity of the statements is that if a chemical substance has a certain chemical composition, then it could not have had any other chemical composition. Then I defend the view that the principle is a conceptual truth by providing a novel derivation of it from the theoretical concept of chemical substance with a sufficient level of formal rigor. The logical principles required for the derivation will also be stated and defended.

Model of the process safety management system at an airline

The purpose of the process safety management system is to identify hazard factors and develop a set of methods to prevent injuries at an airline, occupational illness, material costs in case of damage to property and the environment. The analysis of the structure of occupational pathology depending on the factors of the production environment and the working process for the period 2013–2022 shows that the percentage of diseases associated with the impact of production physical factors for this period remains at the same level. This fact, in turn, confirms the relevance of the chosen study. Analysis and identification of the current production situation is necessary to assess the impact of adverse production factors. In this study, a new approach to the mathematical model for a process safety management system is implemented. Mathematical modeling allows a deeper understanding of the nature of certain phenomena and to obtain information about the real situation, which in turn stimulates the development of new scientific problems and methods of solving them, and is also the basis for choosing specific solutions for the implementation of certain projects. The successful implementation of strategies in order to create a process safety system for a flexible monitoring and management structure depends on how effective its functional structure is; this provision is explained by the fundamental nature of the tasks that are solved at the management stage. The article discusses the theoretical statements concerning mathematical modeling. When creating the model, the apparatus of abstract algebra-set theory – was used. The model developed in the course of the study makes it possible to introduce a model of the process safety management system into the activities of aviation enterprises.

A pulse oximeter for measuring the blood oxygenation level considering the carboxyhemoglobin concentration: principles of development, computer model and accuracy assessment

The main method for estimating the level of arterial blood oxygenation is pulse oximetry, which has the advantages of being fast, simple, reliable, and non-invasive. However, in well-known pulse oximeters, oxygen saturation is determined only by hemoglobin functional fractions, which reduces the device accuracy and is unacceptable in certain clinical cases. The known pulse oximeter improvement that considers the dysfunctional fraction concentration, especially carboxyhemoglobin, when measuring the level of blood oxygenation is an actual scientific and technical task. The research subjects. Mathematical, algorithmic, and technical support of a pulse oximeter that measures blood oxygenation levels considering the carboxyhemoglobin concentration. Objective. To expand the pulse oximeter functionality to consider the concentration of carboxyhemoglobin in arterial blood. Methods. Methods of computer simulation for developing a model and estimating the pulse oximeter accuracy that measures the blood oxygenation level considering the carboxyhemoglobin concentration. Results. The theoretical statements of measuring the level of blood oxygenation considering the carboxyhemoglobin concentration and the simplest pulse oximeter structural diagram for measuring are developed. An additional LED used in the pulse oximeter is proposed, and the wavelength choice is justified on the condition of maximizing the carboxyhemoglobin contribution to the optical density of the biological object. Computer models of a traditional pulse oximeter and a pulse oximeter with an additional LED were developed, simulation research was conducted using the developed models, and the device accuracy for measuring the level of blood oxygenation was estimated considering the carboxyhemoglobin concentration. Conclusions. Simulation studies based on the developed models show that the proposed pulse oximeter, compared with the known one, allows determining and estimating a decrease in blood oxygenation caused by the carboxyhemoglobin concentration increasing in the patient’s blood. Considering that light is also absorbed by the third derivative of hemoglobin, carboxyhemoglobin, increases the accuracy of the proposed pulse oximeter in measuring functional saturation.

Schatten Index of the Sectorial Operator via the Real Component of Its Inverse

In this paper, we study spectral properties of non-self-adjoint operators with the discrete spectrum. The main challenge is to represent a complete description of belonging to the Schatten class through the properties of the Hermitian real component. The method of estimating the singular values is elaborated by virtue of the established asymptotic formulas. The latter fundamental result is advantageous since, of many theoretical statements based upon it, one of them is a concept on the root vectors series expansion, which leads to a wide spectrum of applications in the theory of evolution equations. In this regard, the evolution equations of fractional order with the sectorial operator in the term not containing the time variable are involved. The concrete well-known operators are considered and the advantage of the represented method is convexly shown.

Думи на водещите броя

Issue 58, January 2024 is thematically situated in the areas of rhetoric, argumentation and philosophy. There are eight scholarly articles, divided into two sections: Rhetoric and Argumentation and Philosophy, Communication and Society. The two authors (Ulrike Nespital and Christian Heiliger) of the article “Efficacy Study for Co-Teaching in Practices in Rhetoric and Natural Sciences” are from Justus Liebig University Giessen, Germany. They present the results of a study on rhetoric and more specifically on the formation of presentation skills in students studying technical subjects and science. Hilda Narch is from the Modern University for Business and Science, Lebanon and in her article “Crisis Management Communications System” she presents a theoretical overview of basic concepts related to crisis communication management. This continues a steady tradition of the journal publishing articles by authors from universities in other countries; these are scholars who are established in a particular academic field and who share their expertise as teachers and researchers. Six authors are from Bulgarian educational institutions and research units: Sofia University “St. Kliment Ohridski”, University of National and World Economy, NATFA “Krastio Sarafov”, the American University in Bulgaria – Academic Library, etc. Argumentation as part of the rhetorical heritage is presented in the context of judicial rhetoric; the author Metin Ibriyamov focuses on abductive reasoning and abductive schemes in criminal proceedings; he provides a theoretical overview, presents examples and reaches reasonable conclusions on their use. Two of the articles include the results of an analysis of political rhetoric, in particular presidential and presidential candidate rhetoric, exhibited during debates. Maglena Gurkova provides a rhetorical analysis of the pre-election debate between Emmanuel Macron and Marine Le Pen held on 3 May 2017; she examines the history, organisation, media context, participants' behaviour, argumentation and non-linguistic means. Maryana Mihaylova analyses presidential candidate debates in Bulgaria in 2016, in particular a televised debate between Rumen Radev and Tsetska Tsacheva, and focuses on the non-verbal communication of presidential contenders in the country. The verbal part of both articles is illustrated with visual elements from the debates, which contributes to a quick and accurate decoding of the presented conclusions. Nora Goleshevska is the author of the scientific publication “Giorgio Agamben’s The language of philosophy and the language of poetry: The world in crisis”. The text is an interesting syncretic version, namely a translational commentary, which is an in-depth analysis and translation of Agamben's text entitled “Quando la casa brucia” (“When the house burns”). In this way, the reader has the opportunity to validate the scholarly analysis with the original text of Giorgio Agamben, one of Italy's most renowned contemporary philosophers, translated into Bulgarian. Stoyanka Delibeeva studies scientific publications and normative documents that refer to a topical issue and studies the influence of language learning and multilingual practices on positive identifications with the European Union at the secondary school stage in Bulgaria. The novelty of the article is to establish the affordances of Q-methodology for the implementation of research in this area. Radina Damyanova presents the results of a content analysis of social networks used by academic libraries in Bulgaria and summarizes the results in tables and charts, presenting an up-to-date picture and recommendations for improving the work of these institutions in understanding the opportunities of reaching different audiences in a fast, effective and contemporary way. The issue is interesting and useful in that it brings together both theoretical overviews and methodological statements; both interpretations from a scientific perspective and results from analyses implemented with contemporary methods.

On the unique weak solvability of second-order unconditionally stable difference scheme for the system of sine-Gordon equations

In the present paper, a nonlinear system of sine-Gordon equations that describes the DNA dynamics is considered. A novel unconditionally stable second-order accuracy difference scheme corresponding to the system of sine-Gordon equations is presented. In this work, for the first time in the literature, weak solution of this difference scheme is studied. The existence and uniqueness of the weak solution for the difference scheme are proved in the space of distributions, and the methods of variational calculus are applied. The finite-difference method and the fixed point theory are used in combination to perform numerical experiments that verify the theoretical statements.

Spatial Modeling of the Relationship Between the Social Map and the Level of Educational Development in the Municipalities of the Luján River Basin, Argentina

This study aimed to determine the degree of association between the social map (Synthetic Economic-Housing Index—ISEH) and the level of educational development (Synthetic Educational Index—ISE) modeled for the municipalities of the Lujan River basin. The indices were constructed by applying multivariate analysis methods based on Geographic Information Systems (GIS), and the Exploratory Analysis of Spatial Data determined their links using a spatial decision support system (SDSS). The result facilitated the contrast of the proposed hypothesis. In this sense, a theoretical statement and a methodological tool are built from the cartography. The analysis highlights the importance of contextual variables and their incidence on educational development indicators since the spatial perspective provides the bases to support spatial decision-making at the municipal management level.

Enhanced Solutions to Intuitionistic Fuzzy Multiobjective Linear Fractional Optimization Problems via Lexicographic Method

Optimization involving fuzzy numbers generally, and intuitionistic fuzzy numbers particularly is more and more an essential part of any computational intelligence method; and might be of interest in modeling fuzzy control systems, or carrying out a fuzzy sensitivity analysis. The recent literature includes many research papers related to both theoretical modelling, and practical implementation of fuzzy decision support systems. Fuzzy optimization is one of the main part in such decisionmaking tools. A realistic solution to a fuzzy optimization problem is always desired, and similarly, a Pareto optimal solution to a multiple objective optimization problem is always a need. In this paper we analyze the shortcomings; and eliminate the weaknesses of a solution approach from the literature proposed by Moges et al. in 2023. Firstly, Moges et al. used an accuracy function to de-fuzzify the original intuitionistic fuzzy optimization problem; then linearized the obtained crisp problem; and finally involved fuzzy goals to solve the derived multiple objective linear problem. We present two faulty key points of their approach, namely the de-fuzzification and linearization steps; prove the inappropriateness of their results; and propose some improvements. The final aim in addressing the first key point is to clarify the border between defuzzifications made in accordance to true theoretical statements, and those made for modeling reasons. The methodological improvement we propose is related to the second key point and it assures that Pareto optimal solutions - highly required in multiple objective optimization - are obtained. To illustrate our point of view, we use a numerical example from the literature, and report better numerical results derived by the improved methodology.