Competition Coefficients Research Articles

Three-Phase Resonant Capacitive Power Transfer for Rotary Applications

This article proposes a three-phase resonant capacitive power transfer (RCPT) system for rotating applications requiring loose coupling. Existing plate designs for rotational CPT, such as the stacked four-plate and concentric structures, are found to exhibit imbalances that give rise to ground return or common-mode currents. These are particularly harmful at the high switching frequencies employed by compact and low-cost RCPT systems. Inherently balanced multiphase electrode designs are proposed to address this at the expense of permitting some coupling variation over rotation. Simulations show that three or more phases are required to avoid coupling nulls. While four or more phases may be preferred for applications requiring very stable coupling, three-phase is found to be the most practical solution in the context of cost, complexity, and inductor size. The proposed electrode structure offers high balance, a competitive average coupling coefficient, and a low per-plate resonating inductance. A highly integrated 27.12-MHz RCPT system was designed and implemented to validate these findings while accounting for practical limitations, such as manufacturability and cost. Using primarily commercial-off-the-shelf components, the system transferred 50 W at 25 mm under full rotation with an end-to-end efficiency of 73%.

РОЗРОБЛЕННЯ НАПРЯМІВ ПІДВИЩЕННЯ КОНКУРЕНТОСПРОМОЖНОСТІ ПІДПРИЄМСТВА

У статті оцінено управління конкурентоспроможністю та конкурентні переваги підприємства. З проведеної оцінки видно, що підприємство має такі конкурентні переваги, як: якість продукції, відомість серед споживачів, цінова політика та ступінь охоплення ринку. Завдяки цим перевагам підприємство утримує високі конкурентні позиції. Ключовим етапом був аналіз конкурентоспроможності продукції та самого підприємства, який проводився за допомогою побудови Матриці БКГ, багатокутника конкурентоспроможності та розрахунку комплексного коефіцієнта конкурентоспроможності. Аналіз показав, що послуги підприємства є конкурентними майже на всіх етапах свого життєвого циклу і приносять стабільний дохід. Аналіз конкурентоспроможності підприємства показав, що комплексний коефіцієнт конкурентоспроможності з кожним роком збільшується і в 2020 році становив 2,45, тим самим зміцнюючи позиції підприємства на ринку і серед конкурентів. На основі цього аналізу розроблено напрями підвищення конкурентоспроможності підприємства.

Coexistence and bistability of a competition model with mixed dispersal strategy

In this paper, we investigate a Lotka–Volterra competition model with Danckwerts boundary conditions in a one-dimensional habitat where one species assumes pure random diffusion while another one undergoes mixed movement (both random and directed movements). We focus on the joint influence of advection rate, intrinsic growth rate and interspecific competition coefficient on the competition outcomes. It turns out that there exist some critical curves which separate the stable region of the semitrivial steady states from the unstable one. The locations of these curves determine whether coexistence or bistability occurs. More precisely, there are various tradeoffs between advection rate, intrinsic growth rate and interspecific competition coefficient that allow the transition of competition outcomes including competition exclusion, coexistence and bistability. We illustrate our results in various parameter spaces.

Trade development between China and countries along the Belt and Road: A spatial econometric analysis based on trade competitiveness and complementarity

AbstractThis paper empirically analyses the effect of trade competitiveness and complementarity on the trade development between China and the countries along the Belt and Road (B&R). The study first measures the trade competitiveness and the complementarity between China and the countries along the B&R by using the trade competitiveness coefficient (TCC) and the trade complementarity index (TCI). Then a spatial gravity model is constructed to analyse the effect of trade competitiveness and complementarity on trade development between China and the countries along the B&R. We use generalized method of moments (GMM) and spatial filtering technology to verify the robustness of the model. The results show that the GDP of China and the countries along the B&R, the land area of countries along the B&R, trade complementarity, common language, free trade agreements (FTA), and the B&R Initiative significantly promote the trade development between China and the countries along the B&R, whereas the geographical distance between countries and trade competitiveness significantly inhibit it. Finally, to promote the trade development between China and the countries along the B&R, the present paper puts forward suggestions including improving trade promotion policies between China and the countries along the B&R and vigorously expanding cooperation with complementary industries in the countries along the B&R to enhance trade dependence.

Construction of a multi-echelon supply chain complex network evolution model and robustness analysis of cascading failure

This paper proposes a description rule and an evolutionary algorithm of a dumbbell-shaped multi-echelon supply chain complex network based on node degree preference and the connection preferences of competitive advantage coefficient. Furthermore, an evolutionary model of synthesis network and its subnets of supply chain is established to reveal the evolution of statistical characteristics. The model can reveal the correlation between the synthesis network and its subnets, and is verified by an example. A global network-based and core-echelon failure strategy is proposed based on the model. A node cascading failure algorithm is designed to measure dynamic robustness of a network, and a method for comprehensively evaluating robustness of supply chain complex networks from multiple dimensions is proposed. The impact of dynamic robustness on a supply chain is demonstrated. The research provides a scientific basis for the optimization of multi-echelon supply chain network structure and dynamic robust control.

Study on Quality Decisions in Supply Chain considering the Lagged Time and Retailers Competition

The lagged time on goodwill is a common phenomenon in the process of quality improvement, which plays an important role in making quality strategy of supply chain. With increasing public attention to quality, supply chain quality management has become a research focus in recent years. This paper probes into the lagged time of quality on goodwill under the competitive environment of retailers and constructs a lagged differential equation of quality on goodwill based on the Nerlove–Arrow model. The results indicate that the optimal goodwill and quality are higher under centralized decision-making than under decentralized decision-making; however, whether or not the profit of the entire supply chain is higher under centralized decision-making depends on the span of the lagged time. Under decentralized decision-making, the lagged time of product quality on goodwill is favorable to retailers but unfavorable to manufacturers and vice versa. Therefore, when competition is low, a supply chain tends to adopt centralized decision-making. When competition is intense, it is appropriate for a supply chain to adopt decentralized decision-making. In conclusion, this paper analyzes the effects of the lagged time on the optimal quality level and supply chain profit as well as the effect of the competition coefficient on research findings concerning supply chain profit under centralized and decentralized decision-making to verify the relevant conclusions of this paper.

Performance of a temperature and humidity independent control air-conditioning system based on liquid desiccant for industrial environments

Saving energy consumption of air-conditioning systems is becoming increasingly important in industrial buildings. In this study, measurements were conducted to reveal on-site performance of a full fresh air-conditioning system based on liquid desiccant applied in an industrial factory. Operating the system, temperature and humidity independent control (THIC) can be realized. The results reveal that the THIC system requires higher-temperature chilled water and no reheating process because of the adoption of a liquid desiccant dehumidifier, compared with the conventional vapor compression air-conditioning system. Therefore, a competitive system's coefficient of performance of 3.6 can be realized under the THIC system and an annual electricity-saving ratio of 23.3% can be achieved. In this system, the process air is divided into two parts, and the flow rate ratio of these two parts is discussed to further improve the system's performance. An optimal range of the ratio is determined in this study. When adjusting the ratio from the current 0.72 to 0.5, annual electricity consumption of the THIC system can be further saved by 5.4%. This study would provide valuable experience and reference for energy conservation of industrial air-conditioning systems.

Practical aspects of using the model of the competitiveness development management system

The practical aspect of using the model of management system of development of competitiveness of a general secondary education institution is considered in the article. The prospects of using pedagogical qualimetry as a structural element of managing the competitiveness of an institution of general secondary education are analyzed, the main directions of the use of pedagogical qualimetry and ensuring its competitiveness in the internal and external markets of education, research of the state and tendencies of development of the educational process through the factor submodel are analyzed. The stages of the pedagogical experiment are analyzed. The explanation for the researcher at the ascertaining, forming and control stages of the experiment is given.Management objects are identified: educational process; marketing; financial and economic activities; innovativeness of management system and educational technologies; organizational and corporate culture; strategic and managerial component; logistical and technological support of the educational process; staff competitiveness, which need to be directed by management actions in order to ensure a high level of competitiveness of a general secondary education institution. It is noted, that certain management units in their totality are a certain integrated quality of competitiveness of a general secondary education institution.Criteria for the controls of objects are developed. In determining the weight of these criteria, the method of expert determination of the weights is applied. In order to calculate the coefficient of competitiveness of a General Secondary Education Institution, a survey was conducted among experts and a weighted average of each expert group was rounded to one.The characteristics of four levels (high, sufficient, middle and low) of competitiveness of an institution of general secondary education are formed on the basis of the factor-criterion model, as well as by means of combination of quantitative and descriptive approaches

Stability Analysis of Competition among Companies: A Guide from Predator Prey Modeling

This paper studied the behavior of two companies using predator prey model as the basis. As the companies are competing constantly, it affects them because their interaction determines the availability of resources for their growth. Considering growth of these companies, the parameters which were respectively the carrying capacity and competitive impact of either of the competing companies on each other were included in the model. Equilibrium point and their existence criteria were analyzed to find the threshold that will guarantee the coexistence of both companies or collapse of either of them or both. It was shown that both companies can grow and rise simultaneously, (coexist) by dividing their resources correspondingly or that even the slightest change in their competition coefficient can lead to adverse situation, which may cause complete disappearance of one of the companies or both. We conclude that as long as these companies did not operate beyond their effective carrying capacity and equally maintain their respective competitive advantage, coexistence might be achieved. Some simulations are also given to illustrate our results.

Global dynamics of a general Lotka-Volterra competition-diffusion system in heterogeneous environments

Previously in [ 14 ], we considered a diffusive logistic equation with two parameters, \begin{document}$ r(x) $\end{document} – intrinsic growth rate and \begin{document}$ K(x) $\end{document} – carrying capacity. We investigated and compared two special cases of the way in which \begin{document}$ r(x) $\end{document} and \begin{document}$ K(x) $\end{document} are related for both the logistic equations and the corresponding Lotka-Volterra competition-diffusion systems. In this paper, we continue to study the Lotka-Volterra competition-diffusion system with general intrinsic growth rates and carrying capacities for two competing species in heterogeneous environments. We establish the main result that determines the global dynamics of the system under a general criterion. Furthermore, when the ratios of the intrinsic growth rate to the carrying capacity for each species are proportional — such ratios can also be interpreted as the competition coefficients — this criterion reduces to what we obtained in [ 18 ]. We also study the detailed dynamics in terms of dispersal rates for such general case. On the other hand, when the two ratios are not proportional, our results in [ 14 ] show that the criterion in [ 18 ] cannot be fully recovered as counterexamples exist. This indicates the importance and subtleties of the roles of heterogeneous competition coefficients in the dynamics of the Lotka-Volterra competition-diffusion systems. Our results apply to competition-diffusion-advection systems as well. (See Corollary 5.1 in the last section.)

Mathematical modeling of radiotherapy cancer treatment using Caputo fractional derivative

BackgroundThis paper presents a mathematical model that simulates a radiotherapy cancer treatment process. The model takes into consideration two important radiobiological factors, which are repair and repopulation of cells. The model was used to simulate the fractionated treatment process of six patients. The results gave the population changes in the cells and the final volumes of the normal and cancer cells. MethodThe model was formulated by integrating the Caputo fractional derivative with the previous cancer treatment model. Thereafter, the linear-quadratic with the repopulation model was coupled into the model to account for the cells’ population decay due to radiation. The treatment process was then simulated with numerical variables, numerical parameters, and radiation parameters. The numerical parameters which included the proliferation coefficients of the cells, competition coefficients of the cells, and the perturbation constant of the normal cells were obtained from previous literature. The radiation and numerical parameters were obtained from reported clinical data of six patients treated with radiotherapy. The patients had tumor volumes of 24.1cm3, 17.4cm3, 28.4cm3, 18.8cm3, 30.6cm3, and 12.6cm3 with fractionated doses of 2 Gy for the first two patients and 1.8 Gy for the other four. The initial tumor volumes were used to obtain initial populations of cells after which the treatment process was simulated in MATLAB. Subsequently, a global sensitivity analysis was done to corroborate the model with clinical data. Finally, 96 radiation protocols were simulated by using the biologically effective dose formula. These protocols were used to obtain a regression equation connecting the value of the Caputo fractional derivative with the fractionated dose. ResultsThe final tumor volumes, from the results of the simulations, were 3.58cm3, 8.61cm3, 5.68cm3, 4.36cm3, 5.75cm3, and 6.12cm3, while those of the normal cells were 23.87cm3, 17.29cm3, 28.17cm3, 18.68cm3, 30.33cm3, and 12.55cm3. The sensitivity analysis showed that the most sensitive model factors were the value of the Caputo fractional derivative and the proliferation coefficient of the cancer cells. Lastly, the obtained regression equation accounted for 99.14% of the prediction. ConclusionThe model can simulate a cancer treatment process and predict the results of other radiation protocols.

Estimation Methods of Cost of Competitiveness Potential of a Transport Enterprise

The article deals with a methodological approach to the cost estimation of competitiveness potential of a transport enterprise. The sequence of estimation of competitiveness potential of a transport enterprise is suggested to be carried out in several stages. A competitive status of the transport enterprise is defined at the first stage by means of a construction of competitiveness matrix. The competitiveness coefficient of transportation service is defined at the second stage. Then competitiveness of all services of transport enterprise is analyzed and the average value of competitiveness of all transport and related services is obtained by means of defining the estimation. Having defined the indicators of competitiveness and the cost of transport enterprise, we estimate market cost of competitiveness potential appropriately. At the next stage of the analysis of efficiency of control of competitiveness potential it is necessary to estimate achievement of development aims and strategic plan of the transport enterprise. In order to estimate the development efficiency and competences implementation and competitive advantages in terms of the market we use traditional approach to the analysis of efficiency according to the effect and cost of the resources spent for its obtaining.

Numerical simulation of normal and cancer cells’ populations with fractional derivative under radiotherapy

BackgroundThis paper presents a numerical simulation of normal and cancer cells’ population dynamics during radiotherapy. The model used for the simulation was the improved cancer treatment model with radiotherapy. The model simulated the population changes during a fractionated cancer treatment process. The results gave the final populations of the cells, which provided the final volumes of the tumor and normal cells.MethodThe improved model was obtained by integrating the previous cancer treatment model with the Caputo fractional derivative. In addition, the cells’ population decay due to radiation was accounted for by coupling the linear-quadratic model into the improved model. The simulation of the treatment process was done with numerical variables, numerical parameters, and radiation parameters. The numerical variables include the populations of the cells and the time of treatment. The numerical parameters were the model factors which included the proliferation rates of cells, competition coefficients of cells, and perturbation constant for normal cells. The radiation parameters were clinical data based on the treatment procedure. The numerical parameters were obtained from the previous literature while the numerical variables and radiation parameters, which were clinical data, were obtained from reported data of four cancer patients treated with radiotherapy. The four cancer patients had tumor volumes of 28.4 cm3, 18.8 cm3, 30.6 cm3, and 12.6 cm3 and were treated with different treatment plans and a fractionated dose of 1.8 Gy each. The initial populations of cells were obtained by using the tumor volumes. The computer simulations were done with MATLAB.ResultsThe final volumes of the tumors, from the results of the simulations, were 5.67 cm3, 4.36 cm3, 5.74 cm3, and 6.15 cm3 while the normal cells’ volumes were 28.17 cm3, 18.68 cm3, 30.34 cm3, and 12.54 cm3. The powers of the derivatives were 0.16774, 0.16557, 0.16835, and 0.16. A variance-based sensitivity analysis was done to corroborate the model with the clinical data. The result showed that the most sensitive factors were the power of the derivative and the cancer cells’ proliferation rate.ConclusionThe model provided information concerning the status of treatments and can also predict outcomes of other treatment plans.

Binary adsorption of Cu(II) and Ni(II) on Lai'yang bentonite: Kinetics, equilibrium, competition quantitative and mechanisms investigation

AbstractIn this study, the competitive adsorption of Cu(II) and Ni(II) adsorption onto bentonite were investigated. The effects of initial adsorbate concentration, pH, contact time, temperature on adsorption and the kinetics, thermodynamic, quantification of adsorption competition and competitive mechanisms have been studied. The results indicated that Cu(II) has a higher affinity than Ni(II) for adsorption on bentonite. But the inhibition effect was not noticeable under alkaline conditions. The Langmuir and pseudo‐second‐order kinetics models can be applied to simulate the isothermal adsorption and adsorption dynamic, respectively. Under a single system/binary system, the maximum adsorption capacity of bentonite for Cu(II) and Ni(II) is 12.76/10.57 and 11.12/9.11 mg/g, respectively. The equilibrium adsorption capacity reduction rate is suitable for quantitative characterization of adsorption competition under any concentration conditions; adsorption competition coefficient is more suitable for low concentration adsorption; although the distribution coefficient is not suitable for quantitative adsorption competition at high concentrations, it can be used to characterize the variation of adsorption competitiveness of Cu(II) at different concentrations. The higher electronegativity, lower first hydrolysis constant and Misono softness, and a better “guest‐host” consistency between Cu(II)O6 and the vacancies in the montmorillonite octahedral sheet make the higher affinity of Cu(II) to bentonite and result in the possible ion exchange between Cu(II) in solution and adsorbed Ni(II). In addition, at high concentrations, Cu(II) and Ni(II) precipitates formed on the surface of montmorillonite may cause remained Cu(II) ions in the solution unable to enter the internal space of the montmorillonite octahedron.

On steady state of some Lotka-Volterra competition-diffusion-advection model

In this paper, we study a shadow system of a two species Lotka-Volterra competition-diffusion-advection system, where the ratio of diffusion and advection rates are supposed to be a positive constant. We show that for any given migration, if the product of interspecific competition coefficients of competitors is small, then the shadow system has coexistence state; otherwise we can always find some migration such that it has no coexistence state. Moreover, these findings can be applied to steady state of the two-species Lotka-Volterra competition-diffusion-advection model. Particularly, we show that if the interspecific competition coefficient of the invader is sufficiently small, then rapid diffusion of the invader can drive to coexistence state.

Growth prediction of two bacterial populations in co-culture with lactic acid bacteria.

The co-culture growth of Staphylococcus aureus, Escherichia coli and lactic acid bacteria starter culture in milk was quantitatively evaluated and modelled with a set of coupled differential equations originally proposed by Baranyi and Roberts and by Gimenez and Dalgaard (BR-GD model). The lactic acid bacteria starter culture showed the ability to induce an early stationary phase of both E. coli and S. aureus populations at different combination of temperature (ranging from 12 to 37 ℃) and lactic acid bacteria inocula (from approx. 103 to 106 CFU/ml). First, the prediction ability was performed only with parameters estimated from individual growth curves of E. coli, S. aureus and the lactic acid bacteria in milk (Dataset 1, 21 experiments). Subsequently, the model was extended with the average competition coefficients (E-BR-GD model) that represented quantitative relations among the populations. The prediction ability of this model was validated with the second dataset consisting of seven experiments. Results and also their statistical indices (accuracy and bias factors) showed that the E-BR-GD model improved growth prediction of all involved populations. Thus, the total root mean square error decreased from 0.457, 0.840 and 0.322 log CFU/ml (BR-GD model) to 0.290, 0.245 and 0.333 log CFU/ml (E-BR-GD) for S. aureus, E. coli and lactic acid bacteria, respectively. This approach in growth prediction of multiple competing microbial populations can be used in assessment of S. aureus and E. coli exposure from raw milk cheeses consumption and contribute to decision making in prevention of staphylococcal enterotoxin production.

Interspecific Competition Between Levanderina fissa (Dinophyceae) and the Other Three Microalgal Species in Co-Cultures

Growth interactions between the dinoflagellate Levanderina fissa (=Gyrodinium instriatum) and the other three algal bloom species Skeletonema costatum (Bacillariophyceae), Prorocentrum micans (Dinophyceae), and Chattonella marina (Raphidophyceae) were studied using bi- or tri-algal co-cultures under laboratory conditions. The Lotka-Volterra model was applied to estimate the interspecific competition between them. Results showed that the growth of L. fissa was significantly suppressed in both bi-algal and tri-algal cultures, and the maximum cell densities in co-cultures were only between 21% and 69% of that in mono-culture. L. fissa outcompeted P. micans; however, its effects on S. costatum and C. marina were generally less than the effects of their intraspecific competitions based on the competition coefficients. Contrarily, the inhibitory effects of S. costatum and C. marina on L. fissa were much greater. S. costatum outcompeted the other three species in all co-cultures, and its competition coefficients on the other species were more than 10000 times higher than the opposite. The growth of C. marina was suppressed by S. costatum; however, it outcompeted L. fissa and P. micans. The growth of P. micans was most strongly inhibited in co-cultures, and the maximum cell densities in co-cultures were less than 15% of that in mono-species culture. The results suggested that L. fissa had few advantages in the interspecific competition. The adaptation to low salinity and the utilization of organic phosphorus might be the important reasons for L. fissa to take the competitive predominance in brackish estuarine environments.

Re-evaluating the ‘plankton paradox’ using an interlinked empirical data and a food web model

Species coexistence in the plankton community, which is also known as the ‘plankton paradox’, has been extensively discussed in studies of the aquatic ecosystem. Theoretical work also proves that seasonal variation can produce population chaos, which can reduce species extinction. However, there is still a lack of empirical research to analyze how both species interactions and seasonal forcing affect both species coexistence and system stability in the plankton community. In this work, we model plankton system via combining both seasonal temperature and a food web model with prey preference, and further use the Markov chain Monte Carlo (MCMC) algorithms to estimate model parameters. Theoretical predictions show both internal factor (intraspecific competition coefficient of calanoid copepods) and external factor (seasonal temperature) are the key factors, which can produce population chaos. Meanwhile, phase space reconstruction method shows Lyapunov exponents of empirical data are positive. Both theoretical predictions and empirical data show the plankton community presents the chaotic dynamics, which reduce species extinction and may help understand the ‘plankton paradox’.

Pathology-preserving intensity standardization framework for multi-institutional FLAIR MRI datasets

Fluid-Attenuated Inversion Recovery (FLAIR) MRI are used by physicians to analyze white matter lesions (WML) of the brain, which are related to neurodegenerative diseases such as dementia and vascular disease. To study the causes and progression of these diseases, multi-centre (MC) studies are conducted, with images acquired and analyzed from multiple institutions. Due to differences in acquisition software and hardware, there is variability in image properties, which creates challenges for automated algorithms. This work explores this variability, known as the MC effect, by analyzing nearly 5000 MC FLAIR volumes and proposes an intensity standardization framework to normalize intensity non-standardness in FLAIR MRI, while ensuring the appearance of WML. Results show that original image characteristics varied significantly between scanner vendors and centres, and that this variability was reduced with standardization. To further highlight the utility of intensity standardization, a threshold-based brain extraction algorithm is implemented and compared with a classifier-based approach. A competitive Dice Similarity Coefficient of 81% was achieved on 183 volumes, demonstrating that optimized pre-processing can effectively reduce the variability in MC studies, allowing for simplified algorithms to be applied on large datasets robustly.

Spiraling Asymptotic Profiles of Competition‐Diffusion Systems

AbstractThis paper describes the structure of the nodal set of segregation profiles arising in the singular limit of planar, stationary, reaction‐diffusion systems with strongly competitive interactions of Lotka‐Volterra type, when the matrix of the interspecific competition coefficients is asymmetric and the competition parameter tends to infinity. Unlike the symmetric case, when it is known that the nodal set consists of a locally finite collection of curves meeting with equal angles at a locally finite number of singular points, the asymmetric case shows the emergence of spiraling nodal curves, still meeting at locally isolated points with finite vanishing order. © 2019 Wiley Periodicals, Inc.