CARMEN ELENA STOENOIU

@utcluj.ro

Department Electrical Machines and Drives/ Faculty of Electrical Engineering
Technical University of Cluj -Napoca



                 

https://researchid.co/carmens

RESEARCH INTERESTS

management, economy, accounting

26

Scopus Publications

153

Scholar Citations

6

Scholar h-index

4

Scholar i10-index

Scopus Publications

  • Connecting the Computer Skills with General Performance of Companies—An Eastern European Study
    Carmen Elena Stoenoiu and Lorentz Jäntschi
    MDPI AG
    In the current era, the economic model that measures the dependence of the training offered by companies to their employees on certain variables allows for identifying the steps taken on account of digital transformations, given the fact that companies want to be competitive, to develop sustainably and the positive effect to it spreads globally. However, how digital transformation contributes remains unclear in both the literature and practice. Five descriptors of information on the economy in relation to the digital economy were extracted from the Eurostat database, and data on eight Eastern European countries in the period 2012–2020 served as primary data in the analysis. A generalized linear model was used as a statistical tool to infer the data series. Following the statistical regression analysis, it was found that the variable measuring the share of companies that offered training for the development/improvement of information and communication technology (ICT) skills is influenced by the combined effect of several other variables: ‘country’, ‘country × year’, ‘country × share of ICT personnel in total employees’, year × “share of ICT sector in GDP”. Based on the results, we noticed that the studied countries are included in two groups with distinct features, which influence the obtained GLZ model, showing the increase in the dependency effect or, on the contrary, the decrease in this effect.

  • Sustainable Development of the Economy—A Case Study of the Impacts of the Size of Enterprises and Factors Affecting Performance
    Carmen Elena Stoenoiu and Lorentz Jäntschi
    MDPI AG
    Approaches to the sustainable development of enterprises are a continuous concern of EU countries, contributing to the achievement of national well-being. Companies today face the combined effects of a multitude of factors that affect their results. This study was carried out to analyse the factors that influence the enterprises in the non-financial sector (industry, trade, and services). The analysis used the related data from eight Eastern European countries in the period of 2018–2020, and includes companies by country, size, number of employees, number of companies by number of employees, turnover, added value and average productivity per employee in generating turnover and added value, respectively. To carry out the study, four research questions and four possible hypotheses were used. For data analysis, generalized linear models were used, and four models were obtained and statistically validated. The obtained results led to the identification of the factors associated with the dependent variables that were the basis for the creation of the models.

  • A New Adaptive Eleventh-Order Memory Algorithm for Solving Nonlinear Equations
    S. Panday, Shubham Kumar Mittal, C. Stoenoiu and L. Jäntschi

    In this article, we introduce a novel three-step iterative algorithm with memory for finding the roots of nonlinear equations. The convergence order of an established eighth-order iterative method is elevated by transforming it into a with-memory variant. The improvement in the convergence order is achieved by introducing two self-accelerating parameters, calculated using the Hermite interpolating polynomial. As a result, the R-order of convergence for the proposed bi-parametric with-memory iterative algorithm is enhanced from 8 to 10.5208. Notably, this enhancement in the convergence order is accomplished without the need for extra function evaluations. Moreover, the efficiency index of the newly proposed with-memory iterative algorithm improves from 1.5157 to 1.6011. Extensive numerical testing across various problems confirms the usefulness and superior performance of the presented algorithm relative to some well-known existing algorithms.

  • Circular Economy Similarities in a Group of Eastern European Countries: Orienting towards Sustainable Development
    Carmen Elena Stoenoiu and Lorentz Jäntschi
    MDPI AG
    The transition to a circular economy determines benefits at the level of each country by ensuring the premises for a sustainable economy in the future. The purpose of this study is to analyze indicators that measure the results of the implementation of circular economy through five study directions: Production and Consumption, Waste Management, Secondary Raw Materials, Competitiveness and Innovation, and Global Sustainability and Resilience. The analysis used 11 indicators that allow for the measurement of the evolution of eight Eastern European countries in the years 2012–2020. The study used three working hypotheses, which were all verified. The obtained results allowed for the classification of countries using a composite index and the grouping of countries with the help of cluster analysis using Pearson’s correlation coefficient. In a nutshell, sustainable development requires both economic development and environmental sustainability, and the developed composite index groups the countries’ evolution towards this goal.

  • A computer-based evaluation system: Its design, implementation and results obtained on a general chemistry course
    Carmen Elena Stoenoiu and Lorentz Jäntschi
    EnPress Publisher
    Using multiple evaluation methods and systems give a comprehensive assessment. A computer-based multiple-choice assessment system was designed, implemented, posted online, and used to assess students as part of their final evaluation marks for a discipline. The online system of evaluation was intended to be used multiple times for evaluating the assimilation degree of a specific course at the end of the course. The data recorded for the period 2017–2023 with about 1400 distinct users were used to analyze the performance of the evaluation system. The system worked fine and a slight modification of it served well on remote evaluation during COVID-19 period. However, the upturn of mobile phone applications requires the creation of a system adapted to the new virtual reality.


  • Generalized high-order iterative methods for solutions of nonlinear systems and their applications
    G Thangkhenpau, Sunil Panday, Bhavna Panday, Carmen E. Stoenoiu, and Lorentz Jäntschi
    American Institute of Mathematical Sciences (AIMS)
    <abstract><p>In this paper, we have constructed a family of three-step methods with sixth-order convergence and a novel approach to enhance the convergence order $ p $ of iterative methods for systems of nonlinear equations. Additionally, we propose a three-step scheme with convergence order $ p+3 $ (for $ p\\geq3 $) and have extended it to a generalized $ (m+2) $-step scheme by merely incorporating one additional function evaluation, thus achieving convergence orders up to $ p+3m $, $ m\\in\\mathbb{N} $. We also provide a thorough local convergence analysis in Banach spaces, including the convergence radius and uniqueness results, under the assumption of a Lipschitz-continuous Fréchet derivative. Theoretical findings have been validated through numerical experiments. Lastly, the performance of these methods is showcased through the analysis of their basins of attraction and their application to systems of nonlinear equations.</p></abstract>

  • Is triple crossed C<inf>28</inf> cyclic polyyne cluster a stable conformation?
    Carmen E. Stoenoiu, Mihai V. Putz, and Lorentz Jäntschi
    Informa UK Limited

  • Accelerating the Convergence in the Identification of PV Cells Parameters
    Carmen Elena Stoenoiu and Lorentz Jäntschi
    IEEE
    The current trend in energy sources is towards the large-scale use of small-scale photovoltaic (PV) systems for local energy supply. The today's common commercial PV systems today include PV cells of various manufactures and origins based mostly on a large-area p-n junction made of silicon. The characteristic equation describes the non-linear dependence between current and voltage and the parameters values of the characteristic equation define the working regime of the PV system. Parameters identification involves a series of iterations in which the sum of squared errors is minimized (and thus the chance of observation is maximized). A large number of iterations are required if the optimization follows the usual course from the solution proposed by the vertical offsets to the perpendicular offsets. In the present work, an intermediate solution is used to speed up the convergence.

  • A Computer Based Evaluation System: Design, Implementation and Results on General Chemistry
    Carmen Elena Stoenoiu and Lorentz Jäntschi
    IEEE
    A computer based multiple choice multiple answers evaluation system has been designed, implemented, posted online and used to evaluate students on general chemistry for the last 10 years. In this paper, the design, implementation, and some results regarding the students' performances are presented and discussed.

  • Simultaneous Determinations for the Internal Resistance of Three Batteries. Three Analytical Methods Involved
    Carmen E. STOENOIU and Lorentz JÄNTSCHI
    IEEE
    Surprisingly or not, batteries were the primary source of electricity before the development of electric generators and electrical grids. Perhaps Voltaic pile was the first electrical battery that could continuously provide an electric current to a circuit, even if the electrochemical behavior of zinc and copper in a bimetallic arch, in contact with the electrolytes of muscle tissue were observed before. Ordinary batteries consist of one or more electrochemical cells. A cell is created by placing electrodes in an electrolyte where a chemical reaction either generates (at battery use) or uses (at battery recharging) an electric current. Here a very simple circuit has been used to provide raw data for estimating the electromotive force of a power source. The circuit has been used to measure pairs of potential versus intensity for three commercial batteries. From measured data three methods were employed to provide estimates of the internal resistance and electromotive force. The estimating of the internal resistances is discussed.

  • Sustainable Development—A Path to a Better Future
    Carmen Elena Stoenoiu
    MDPI AG
    The need for sustainable development is a common concern for many countries, and the level reached by each country validates the efforts made and the effects of their associated well-being. In this study, an analysis of the indicators included in SDG-9 was performed, indicators that aim to achieve sustainable industrialization, increase research and innovation, and create a resilient infrastructure. The analysis used nine indicators that measure the situation of eight Eastern European countries during 2013–2019 to signal improvements or deteriorations in situations. The study used three working hypotheses that were verified and presented the evolution of countries in the aforementioned years. The results obtained led to the ranking of the countries by evaluating their economies from the perspective of the effects obtained by the method of sustainable development, thus categorizing the countries into ones with real, moderate, and low progress.

  • Renewable energy in European countries, retrospective analysis
    C E Stoenoiu, I Birou, C Cristea, and F M Serban
    IOP Publishing
    Abstract This study performs an exploratory analysis of the evolution of primary production of RES for EU28 countries over the ten years studied. Through the analysis, the document presents: the structure of production by sectors of production and by renewable energy sources, analyses the evolution of the mentioned indicators both in total and in detail on each renewable energy source and allows the identification of differences in the level of production from RES: between countries and regions. The analysis shows that these countries have implemented EU strategies in the field and exceeded the proposed target for 2020 starting from 2017. Among the most important RESs in primary energy production were the sources: Hydro, Wind and Solar, in the countries from the EU28 due to the existence of a natural potential that has been exploited and encouraged by the country-specific internal policies, but also due to the development of technologies and lower costs for these renewable energy sources.

  • Evolution of renewable energy consumption in the European countries
    C E Stoenoiu, M C Balan, F M Serban, and C Cristea
    IOP Publishing
    Abstract This study performs an exploratory analysis of the evolution of consumption of RES for EU28 countries over the ten years studied. Through the analysis, the document presents: the consumption by sectors of production and by renewable energy sources, analyses the evolution of consumption from RES: between countries and regions. Regarding the consumption of RES, it is increasing, reaching in 2017 compared to 2008 to increase by 147.8%.

  • Retrospective analysis of the evolution of industrial production in relation to energy consumption
    Carmen-Elena Stoenoiu
    IEEE
    The study allows to know the evolution, for ten years, of the production in industry and of the energy consumption for the 27 countries of the EU. A comparative analysis was performed in which it can be seen how each country evolved, then the countries where the increase of production determined the increase of energy consumption were established, but also the countries where this connection is not direct. At the same time, the evolution of the production by activity sectors was determined, this allowing the knowledge of the sectors from each country that contribute to the achievement of the gross domestic product and of the economic well-being.

  • Performance analysis of grid-connected rooftop solar photovoltaic systems using different photovoltaic technologies: A case study in Romania
    Ciprian Cristea, Maria Cristea, Radu-Adrian Tirnovan, Iulian Birou, Carmen Elena Stoenoiu, and Florica Mioara Serban
    IEEE
    Solar energy is one of the most important unlimited renewable energy sources that is becoming an increasingly used alternative to generate cleaner electricity. The efficiency of solar photovoltaic technologies has improved considerably, especially in the last decade. This study investigates the performance of a 6-kW grid-connected residential rooftop photovoltaic systems that are using various photovoltaic modules technologies, namely monocrystalline silicon, polycrystalline silicon, heterojunction with intrinsic thin layer, thin film copper indium gallium selenide, cadmium telluride and amorphous silicon for a residence in Romania. The results highlight that thin film copper indium gallium selenide technology is the most suitable in terms of monthly average performance ratio, while monocrystalline silicon panel is the most appropriate option in terms of ratio between produced electricity and occupied area. The findings of this paper are valuable for the stakeholders in establishing the photovoltaic modules technologies that are suitable for the investigated location or other zones with similar climatic characteristics.

  • The Evolution of Efficiency Indicators in the Economies of European Countries
    Stoenoiu Carmen-Elena
    IEEE
    This study includes an analysis of resource and energy productivity indicators over ten years. Through these indicators it was possible to obtain the evolution of these indicators during the years studied as well as the differences between countries because of the achievements in those economies. The comparative analysis of the two indicators shows that the evolution trend is similar during 2019. Subsequently, a ranking of countries was made according to 5 indicators: Energy productivity, Resource productivity, Greenhouse gas emissions per capita and Eco innovation index. According to this ranking, it can be seen which are the countries that registered high values for the productivity and eco-innovation indicators and countries where the Greenhouse gas emissions per capita indicator registered decreasing values.

  • The analysis of government expenditures in the european union
    F. M. Șerban, Romania Drives and C. Stoenoiu

    This article analyses data on general government expenditure, at the level of the European Union (EU 28) according to the Classification of the Functions of Government – COFOG over the 2008-2017 period. Data shows that the expenditures increased at the beginning of the economic crisis in all EU countries, being followed by a slowdown in expenditures growth. All countries have adopted policies in order to reduce government expenditures towards the end of the period, aiming to increase their efficiency. Usually in high-income countries, compared with low-income countries, government expenditures are much larger as percent of gross domestic product (GDP), but the relations are not very strong though.

  • Comparative analysis for estimating production costs
    Carmen-Elena Stoenoiu
    EDP Sciences
    The analysis of the cost of production is a complex problem, being very useful in the planning and control process as well as in production and sales. In this study, this was done using three methods: accounting analysis, high-low and regression analysis that allowed cost elements to be identified through a cost equation that can be used in planning and control analysis or in sales activity. At the same time, the evolution of the cost elements was achieved using two estimates used by the accounting method. The High-Low method allowed the determination of the minimum and maximum activity level at one year's level, which was then analyzed through the company's available activity range. The multivariate regression analysis determined the analysis of the obtained model, being linear, thus establishing the production line.

  • Sensitivity of indicators used in cost-volume-profit analysis
    Carmen-Elena Stoenoiu
    EDP Sciences
    The need for cost-volume-profit analysis (CVP) starts from the need to optimize and manage costs due to unforeseen events that accompany economic activity in all areas. In this paper, the dependency relationship between the three cost-volume-profit indicators was analyzed to highlight the need to permanently track and optimize these variables so that managers' decisions can be supported by adaptive analyzes to concrete needs. The study also includes a sensitivity analysis that has shown that the magnitude and meaning of changes occurring when changes occur to one or more variables may be different due to direct and inverse relationships that are established between these variables.

  • Pattern of energy productivity and gross domestic product among european countries


  • Patterns in enterprise management software
    Carmen Elena Stoenoiu
    Walter de Gruyter GmbH
    Abstract In this paper a study was conducted on the complex integrated software that exists on the Romanian market. This consisted in identifying and analysing the size of the enterprise, the number of users, the technical characteristics determined by the type and number of modules included in the software and other information related to the implementation, according to the supplier's specifications. The primary analysis made it possible to obtain results regarding the integrated software market in Romania in terms of customer size, field of activity, software products that include the biggest number of modules. By statistical analysis using the multivariate cluster grouping exploration technique, the degree of similarity between the software and the modules was determined, calculating the distance by means of three measurement methods: the Euclidean distance, the percentage of disagreement, and the correlation coefficient 1- Pearson-r.

  • Role of academic community in defining professional route: Students' perception


  • Students perception of degree of academic community involvement in academic life


  • Undergraduate students assessment on materials chemistry topic using an auto-calibrated online system
    Lorentz JÄNTSCHI, Carmen Elena STOENOIU, and Sorana Elena BOLBOACMĂ
    Springer Netherlands

RECENT SCHOLAR PUBLICATIONS

  • Connecting the Computer Skills with General Performance of Companies—An Eastern European Study
    CE Stoenoiu, L Jntschi
    Sustainability 16 (22), 10024 2024

  • Sustainable Development of the Economy—A Case Study of the Impacts of the Size of Enterprises and Factors Affecting Performance
    CE Stoenoiu, L Jntschi
    Sustainability 16 (13), 5376 2024

  • A New Adaptive Eleventh-Order Memory Algorithm for Solving Nonlinear Equations
    S Panday, SK Mittal, CE Stoenoiu, L Jntschi
    Mathematics 12 (12), 1809 2024

  • Circular Economy Similarities in a Group of Eastern European Countries: Orienting towards Sustainable Development
    CE Stoenoiu, L Jntschi
    Sustainability 16 (4), 1593 2024

  • Is triple crossed C28 cyclic polyyne cluster a stable conformation?
    CE Stoenoiu, MV Putz, L Jntschi
    Fullerenes, Nanotubes and Carbon Nanostructures 32 (1), 55-67 2024

  • Generalized high-order iterative methods for solutions of nonlinear systems and their applications
    G Thangkhenpau, S Panday, B Panday, CE Stoenoiu, L Jntschi
    AIMS Math 9 (3), 6161-6182 2024

  • A computer based evaluation system: design, implementation and results on general chemistry
    CE Stoenoiu, L Jntschi
    2023 International Conference on Computational Science and Computational 2023

  • Accelerating the convergence in the identification of PV cells parameters
    CE Stoenoiu, L Jntschi
    2023 International Conference on Computational Science and Computational 2023

  • Least Squares for Generalized Gauss–Laplace Distribution of the Error in Certain Nonlinear Regressions with Perpendicular Offsets
    CE Stoenoiu, L Jntschi
    International Conference on Mathematical Modeling in Physical Sciences, 153-162 2023

  • Simultaneous Determinations for the Internal Resistance of Three Batteries. Three Analytical Methods Involved
    CE STOENOIU, L JNTSCHI
    2023 10th International Conference on Modern Power Systems (MPS), 01-05 2023

  • Analysis and evaluation of the risk of non-competitiveness
    CE Stoenoiu, C Cristea, FM Serban
    IOP Conference Series: Materials Science and Engineering 1256 (1), 012030 2022

  • Reducing the Economic Risk and Increasing the Operational Profit
    CE Stoenoiu
    IOP Conference Series: Materials Science and Engineering 1256 (1), 012029 2022

  • Sustainable development—A path to a better future
    CE Stoenoiu
    Sustainability 14 (15), 9192 2022

  • The effect of the COVID-19 pandemic on European economies
    CE STOENOIU
    8th Review of Management and Economic Engineering International Management 2022

  • The impact of the COVID-19 pandemic on businesses in european countries
    CE STOENOIU
    8th Review of Management and Economic Engineering International Management 2022

  • The Evolution of Efficiency Indicators in the Economies of European Countries
    S Carmen-Elena
    2021 International Conference on Electromechanical and Energy Systems 2021

  • Retrospective analysis of the evolution of industrial production in relation to energy consumption
    CE Stoenoiu
    2021 International Conference on Electromechanical and Energy Systems 2021

  • Performance analysis of grid-connected rooftop solar photovoltaic systems using different photovoltaic technologies: a case study in Romania
    C Cristea, M Cristea, RA Tirnovan, I Birou, CE Stoenoiu, FM Șerban
    2021 International Conference on Electromechanical and Energy Systems 2021

  • The variation of the turnover and its effect on the exploitation risk
    CE Stoenoiu, FM Serban, C Cristea
    IOP Conference Series: Materials Science and Engineering 1169 (1), 012033 2021

  • Productivity assessment of the Romanian construction industry using Malmquist Productivity Index
    C Cristea, M Cristea, FM Șerban, C Făgărășan, CE Stoenoiu
    IOP Conference Series: Materials Science and Engineering 1169 (1), 012018 2021

MOST CITED SCHOLAR PUBLICATIONS

  • Sensitivity of indicators used in cost-volume-profit analysis
    CE Stoenoiu
    MATEC Web of Conferences 184, 04003 2018
    Citations: 19

  • Sustainable development—A path to a better future
    CE Stoenoiu
    Sustainability 14 (15), 9192 2022
    Citations: 16

  • Mobile Phase Optimization Method for Steroids Separation
    CE Stoenoiu, SD Bolboacă, L Jntschi
    Applied Medical Informatics 18 (1-2), 17-24 2006
    Citations: 13

  • National trends on agricultural crops production: Cluster analysis
    L JNTSCHI, SD Bolboaca, CE Stoenoiu
    Bulletin of University of Agricultural Sciences and Veterinary Medicine 2007
    Citations: 10

  • Comparative analysis for estimating production costs
    CE Stoenoiu
    MATEC Web of Conferences 184, 04004 2018
    Citations: 8

  • Linking assessment to e-learning in microbiology and toxicology for undergraduate students
    L Jantschi, CE Stoenoiu, SD Bolboaca
    EUROCON 2007-The International Conference on" Computer as a Tool", 2447-2452 2007
    Citations: 8

  • Performance analysis of grid-connected rooftop solar photovoltaic systems using different photovoltaic technologies: a case study in Romania
    C Cristea, M Cristea, RA Tirnovan, I Birou, CE Stoenoiu, FM Șerban
    2021 International Conference on Electromechanical and Energy Systems 2021
    Citations: 6

  • Molecular descriptors family on vertex cutting: relationships between acelazolamide structures and their inhibitory activity
    SD Bolboacă, MM Marta, CE Stoenoiu, L Jntschi
    Applied Medical Informatics 25 (3, 4), 65-74 2009
    Citations: 6

  • Circular Economy Similarities in a Group of Eastern European Countries: Orienting towards Sustainable Development
    CE Stoenoiu, L Jntschi
    Sustainability 16 (4), 1593 2024
    Citations: 4

  • Evolution of renewable energy consumption in the European countries
    CE Stoenoiu, MC Balan, FM Serban, C Cristea
    IOP Conference Series: Earth and Environmental Science 664 (1), 012018 2021
    Citations: 4

  • Pattern of Energy Productivity and Gross Domestic Product Among European Countries
    CE Stoenoiu
    Problemy Ekorozwoju 13 (2), 113-123 2018
    Citations: 4

  • Model formulation & interpretation-from experiment to theory
    CE Stoenoiu, SD Bolboaca, L Jntschi
    Int. J. Pure Appl. Math 47, 9-16 2008
    Citations: 4

  • Generalized high-order iterative methods for solutions of nonlinear systems and their applications
    G Thangkhenpau, S Panday, B Panday, CE Stoenoiu, L Jntschi
    AIMS Math 9 (3), 6161-6182 2024
    Citations: 3

  • Distribution Fitting 4. Benford Test on a Sample of Observed Genotypes Number from Running of a Genetic Algorithm.
    L Jntschi, SD Bolboacă, CE Stoenoiu, M Iancu, MM Marta, EM Pică, ...
    Bulletin of the University of Agricultural Sciences & Veterinary Medicine 2009
    Citations: 3

  • Key issues in choosing a university.
    MM Marta, CE Stoenoiu, L Jntschi, I Abrudan
     2009
    Citations: 3

  • A New Adaptive Eleventh-Order Memory Algorithm for Solving Nonlinear Equations
    S Panday, SK Mittal, CE Stoenoiu, L Jntschi
    Mathematics 12 (12), 1809 2024
    Citations: 2

  • Is triple crossed C28 cyclic polyyne cluster a stable conformation?
    CE Stoenoiu, MV Putz, L Jntschi
    Fullerenes, Nanotubes and Carbon Nanostructures 32 (1), 55-67 2024
    Citations: 2

  • A computer based evaluation system: design, implementation and results on general chemistry
    CE Stoenoiu, L Jntschi
    2023 International Conference on Computational Science and Computational 2023
    Citations: 2

  • Retrospective analysis of the evolution of industrial production in relation to energy consumption
    CE Stoenoiu
    2021 International Conference on Electromechanical and Energy Systems 2021
    Citations: 2

  • Productivity assessment of the Romanian construction industry using Malmquist Productivity Index
    C Cristea, M Cristea, FM Șerban, C Făgărășan, CE Stoenoiu
    IOP Conference Series: Materials Science and Engineering 1169 (1), 012018 2021
    Citations: 2