This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
The goal of this study is to examine and identify the factors influencing customer attitude towar... more The goal of this study is to examine and identify the factors influencing customer attitude toward and intention to use digital wallets (electronic wallets, e-wallets) during and after the COVID-19 pandemic. A total of 257 correctly fulfilled questionnaires from an online survey were summarized. The main features of e-wallet payment systems were classified with a focus on consumer satisfaction via the integration of classic and modern data analysis methods. Structural Equation Modeling (SEM) was preferred to reveal the dependencies between the variables from e-wallets users’ perspective. The designed model can discover and explain the underlying relationships that determine the e-wallets’ adoption mechanism. The obtained results lead to specific recommendations to stakeholders in the value chain of payment processing. Financial regulatory authorities could employ the presented results in planning the development of payment systems. E-commerce marketers could utilize the proposed met...
The purpose of the paper is to systematically analyze the capabilities of big data technology to ... more The purpose of the paper is to systematically analyze the capabilities of big data technology to solve important problems in electronic commerce. The role of big data as one of the central priorities in modern information technologies for online sellers and buyers is underlined. Big data methods to improve the basic functional areas of e-commerce: marketing, payments, supply chain, and management are described. A new model for automation of key business processes in e-commerce through new technology is presented. The model is verified using practical examples of e-commerce activities. The process of e-commerce modernization requires additional infrastructure, new methods and modern software for better data organizing, customer personalization and improved decision making.
Small and medium-sized enterprises represent 99% of all enterprises in the EU and in Bulgaria and... more Small and medium-sized enterprises represent 99% of all enterprises in the EU and in Bulgaria and generate about two thirds of gross value added. This makes small business competitiveness of utmost importance for the economies of both the Union and the country. Applying business intelligence in the decision making process of such companies could enhance their receptivity and adaptivity towards market changes and could create a new organizational culture aimed at continuous improvement. The objective of the presented research is to identify the current state and problems related to the application of business intelligent systems in small and medium enterprises in South Central Bulgaria (South Central Statistical Area), to explain the reasons for the status of Bulgarian companies, and to develop recommendations for efficient use of the business intelligence by small and medium-sized business.
The piecewise interpolation method for constructing a smooth curve passing through the sequence o... more The piecewise interpolation method for constructing a smooth curve passing through the sequence of points in the plane is presented. For each section, an interpolation between two points is done by a rational function describing the curve of Agnesi. Conditions of existence of the curve on a section and the methodology for determining its parameters are established. The interpolation error is estimated. The proposed scheme for $$C^1$$C1 rational interpolation can be used to solve the problems of shape preserving interpolation. The described algorithm can be adapted for interpolation of convex, monotonous, or positive datasets. Examples of numeric data are given.
In accordance with a presented classification of the types design procedures, a short overview ha... more In accordance with a presented classification of the types design procedures, a short overview has been provided, of the latest software for the design of mechanisms. The present overview shows that the theoretical basis for developing every design system leads to the construction of a formal mathematical model of a set of mechanism structures with a greater or smaller degree
In order to assess the impact of the COVID-19 pandemic on learning process of students in the Sou... more In order to assess the impact of the COVID-19 pandemic on learning process of students in the South-Central region of Bulgaria, an online survey was conducted at the University of Plovdiv Paisii Hilendarski during the period from November 17 to December 5, 2020. The questionnaire was created via Google Forms and the link was shared with the students through social media (Facebook pages of the University and Faculty of Economics and Social Sciences). A total of 134 questionnaires were correctly completed during the study period. For analysis of the collected data the percentage distribution is calculated and statistical methods and machine learning methods are applied. During the lockdown, all respondents are trained remotely, with about 60% (80) of the learners learning entirely in an electronic environment. Most of the trainees (62%) used a laptop to participate in the learning process. Students face various problems, such as lack of sufficient means of subsistence (51%), health problems (47%), internet connectivity problems (32%) and lack of suitable conditions for learning at home (21%). Students from small settlements and those with incomes below the poverty line face serious challenges during the pandemic.
The declared state of emergency and the measures taken against the spread of coronavirus by gover... more The declared state of emergency and the measures taken against the spread of coronavirus by governments have increased Internet shopping. All companies, regardless of size and type of business activity, had to adapt their business models to the new circumstances through transformation of their business processes and offering products or services tailored to the changing customer behavior. This study aims to analyze the peculiarities of online sales during the COVID-19 health crisis via the integration of classic and modern data analysis methods. The purpose of the paper is to identify the main factors determining user behavior and examine their impact on customer satisfaction in e-commerce. The survey method and structural equation modeling (SEM) were used to recognize the dependencies between variables from the online users’ perspective. The satisfaction determinants indicated and described in the paper affect differently the perceived value for the customers. As this value is subj...
In order to help curb the spread of the COVID-19 pandemic, this paper develops a multi-attribute ... more In order to help curb the spread of the COVID-19 pandemic, this paper develops a multi-attribute decision-making framework for COVID-19 vaccine evaluation based on their major clinical characteristics and efficacy. Firstly, a new multi-criteria Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) modification has been constructed in an interval-valued Fermatean fuzzy (IVFF) environment, improving the shortcomings of traditional TOPSIS. Secondly, a new conceptual framework for static and dynamic evaluation of COVID-19 vaccines has been built. The proposed methodology incorporates a variety of crisp and fuzzy MCDM methods. The analysis of the results of two practical examples shows that the new framework for vaccine comparison is feasible and effective, and finally, some recommendations for enhancement of government anti-COVID-19 strategies are suggested.
In order to assess the impact of the COVID-19 pandemic on learning process of students in the Sou... more In order to assess the impact of the COVID-19 pandemic on learning process of students in the South-Central region of Bulgaria, an online survey was conducted at the University of Plovdiv Paisii Hilendarski during the period from November 17 to December 5, 2020. The questionnaire was created via Google Forms and the link was shared with the students through social media (Facebook pages of the University and Faculty of Economics and Social Sciences). A total of 134 questionnaires were correctly completed during the study period. For analysis of the collected data the percentage distribution is calculated and statistical methods and machine learning methods are applied. During the lockdown, all respondents are trained remotely, with about 60% (80) of the learners learning entirely in an electronic environment. Most of the trainees (62%) used a laptop to participate in the learning process. Students face various problems, such as lack of sufficient means of subsistence (51%), health problems (47%), internet connectivity problems (32%) and lack of suitable conditions for learning at home (21%). Students from small settlements and those with incomes below the poverty line face serious challenges during the pandemic.
This research aims to analyse the applications of IoT in agriculture and to compare the most wide... more This research aims to analyse the applications of IoT in agriculture and to compare the most widely used IoT platforms. The problem of determining the most appropriate IoT system depends on many factors, often expressed by incomplete and uncertain estimates. In order to find a feasible decision, this study develops a multi-criteria framework for IoT solution selection in a fuzzy environment. In the proposed framework, a new modification of the Multi-Attribute Border approximation Area Comparison (MABAC) method with a specific distance measure via intuitionistic fuzzy values has been presented as a decision analysis method. The new technique is more precise than existing crisp and fuzzy analogues, as it includes the three components of intuitionistic numbers (degree of membership, degree of non-membership and hesitancy degree) and the relationships between them. The effectiveness of the new decision-making framework has been verified through an illustrative example of ranking IoT pla...
In this paper, we present a new fuzzy methodology for early students' failure detection. High... more In this paper, we present a new fuzzy methodology for early students' failure detection. High school background, subjects studied in the university and activities in learning management systems were determined to be the factors influencing students' performance. After selection of the impact factors of students' assessment, we convert linguistic evaluations into fuzzy numbers and employ multi-criteria methods for educational data processing. In two practical examples, the aggregate students' scores were calculated by using fuzzy multi-criteria algorithms. The obtained students' ranking helps instructors during the semester to detect students who will drop out the course and to plan additional learning activities for these students. In the future, we plan on analysing students' data from different university's courses and majors and mining several academic years in order to create a reliable assessment index for early prediction of students' failure.
Proceedings of the 9th Balkan Conference on Informatics, 2019
Small and medium-sized enterprises represent 99% of all enterprises in the EU and in Bulgaria and... more Small and medium-sized enterprises represent 99% of all enterprises in the EU and in Bulgaria and generate about two thirds of gross value added. This makes small business competitiveness of utmost importance for the economies of both the Union and the country. Applying business intelligence in the decision making process of such companies could enhance their receptivity and adaptivity towards market changes and could create a new organizational culture aimed at continuous improvement. The objective of the presented research is to identify the current state and problems related to the application of business intelligent systems in small and medium enterprises in South Central Bulgaria (South Central Statistical Area), to explain the reasons for the status of Bulgarian companies, and to develop recommendations for efficient use of the business intelligence by small and medium-sized business.
The purpose of the paper is to systematically analyze the capabilities of big data technology to ... more The purpose of the paper is to systematically analyze the capabilities of big data technology to solve important problems in electronic commerce. The role of big data as one of the central priorities in modern information technologies for online sellers and buyers is underlined. Big data methods to improve the basic functional areas of e-commerce: marketing, payments, supply chain, and management are described. A new model for automation of key business processes in e-commerce through new technology is presented. The model is verified using practical examples of e-commerce activities. The process of e-commerce modernization requires additional infrastructure, new methods and modern software for better data organizing, customer personalization and improved decision making.
Membership functions are a key concept in fuzzy set theory and their correctness and precision ar... more Membership functions are a key concept in fuzzy set theory and their correctness and precision are essential for the accuracy of obtained results. This article discusses the use of Bezier curve to construct a membership function. Based on the frequency distribution of data by minimization, the coordinate formulas of the control points that define the curve are derived. Use of the described membership function is illustrated by an example. These formulas are applied to bispectral index data sets in order to compare with other published method. MSC: 03E72, 65D05, 65D10, 65D15 keywords: Fuzzy set, Membership function, Bezier curve, Least-squares minimization ∗Accepted for publication on March 5, 2018 †[email protected] Faculty of Economics and Social Sciences, University of Plovdiv Paisii Hilendarski, 24 ”Tzar Assen” str., Plovdiv, Bulgaria ‡[email protected] Faculty of Economics and Social Sciences, University of Plovdiv Paisii Hilendarski, 24 ”Tzar Assen” str., Plovdiv, Bulgari...
Despite the worldwide physical closing of educational institutions due to the pandemic of COVID-1... more Despite the worldwide physical closing of educational institutions due to the pandemic of COVID-19 in the spring of 2020, the learning process was not interrupted. Learning management systems and digital tools for online collaboration ensured a safe distance and continuity of educational activities. However, the rapid transition to remote learning in electronic environment has created a number of challenges in higher education. In order to derive longterm benefits from the changes in the way of teaching and examining, the paper explores the possibilities of IoT technology for continuous monitoring and flexible management of the learning process. The proposed framework for IoT application in educational activities will facilitate the adaptation of studying process at universities to the new circumstances.
In accordance with a presented classification of the types design procedures, a short overview ha... more In accordance with a presented classification of the types design procedures, a short overview has been provided, of the latest software for the design of mechanisms. The present overview shows that the theoretical basis for developing every design system leads to the construction of a formal mathematical model of a set of mechanism structures with a greater or smaller degree
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
The goal of this study is to examine and identify the factors influencing customer attitude towar... more The goal of this study is to examine and identify the factors influencing customer attitude toward and intention to use digital wallets (electronic wallets, e-wallets) during and after the COVID-19 pandemic. A total of 257 correctly fulfilled questionnaires from an online survey were summarized. The main features of e-wallet payment systems were classified with a focus on consumer satisfaction via the integration of classic and modern data analysis methods. Structural Equation Modeling (SEM) was preferred to reveal the dependencies between the variables from e-wallets users’ perspective. The designed model can discover and explain the underlying relationships that determine the e-wallets’ adoption mechanism. The obtained results lead to specific recommendations to stakeholders in the value chain of payment processing. Financial regulatory authorities could employ the presented results in planning the development of payment systems. E-commerce marketers could utilize the proposed met...
The purpose of the paper is to systematically analyze the capabilities of big data technology to ... more The purpose of the paper is to systematically analyze the capabilities of big data technology to solve important problems in electronic commerce. The role of big data as one of the central priorities in modern information technologies for online sellers and buyers is underlined. Big data methods to improve the basic functional areas of e-commerce: marketing, payments, supply chain, and management are described. A new model for automation of key business processes in e-commerce through new technology is presented. The model is verified using practical examples of e-commerce activities. The process of e-commerce modernization requires additional infrastructure, new methods and modern software for better data organizing, customer personalization and improved decision making.
Small and medium-sized enterprises represent 99% of all enterprises in the EU and in Bulgaria and... more Small and medium-sized enterprises represent 99% of all enterprises in the EU and in Bulgaria and generate about two thirds of gross value added. This makes small business competitiveness of utmost importance for the economies of both the Union and the country. Applying business intelligence in the decision making process of such companies could enhance their receptivity and adaptivity towards market changes and could create a new organizational culture aimed at continuous improvement. The objective of the presented research is to identify the current state and problems related to the application of business intelligent systems in small and medium enterprises in South Central Bulgaria (South Central Statistical Area), to explain the reasons for the status of Bulgarian companies, and to develop recommendations for efficient use of the business intelligence by small and medium-sized business.
The piecewise interpolation method for constructing a smooth curve passing through the sequence o... more The piecewise interpolation method for constructing a smooth curve passing through the sequence of points in the plane is presented. For each section, an interpolation between two points is done by a rational function describing the curve of Agnesi. Conditions of existence of the curve on a section and the methodology for determining its parameters are established. The interpolation error is estimated. The proposed scheme for $$C^1$$C1 rational interpolation can be used to solve the problems of shape preserving interpolation. The described algorithm can be adapted for interpolation of convex, monotonous, or positive datasets. Examples of numeric data are given.
In accordance with a presented classification of the types design procedures, a short overview ha... more In accordance with a presented classification of the types design procedures, a short overview has been provided, of the latest software for the design of mechanisms. The present overview shows that the theoretical basis for developing every design system leads to the construction of a formal mathematical model of a set of mechanism structures with a greater or smaller degree
In order to assess the impact of the COVID-19 pandemic on learning process of students in the Sou... more In order to assess the impact of the COVID-19 pandemic on learning process of students in the South-Central region of Bulgaria, an online survey was conducted at the University of Plovdiv Paisii Hilendarski during the period from November 17 to December 5, 2020. The questionnaire was created via Google Forms and the link was shared with the students through social media (Facebook pages of the University and Faculty of Economics and Social Sciences). A total of 134 questionnaires were correctly completed during the study period. For analysis of the collected data the percentage distribution is calculated and statistical methods and machine learning methods are applied. During the lockdown, all respondents are trained remotely, with about 60% (80) of the learners learning entirely in an electronic environment. Most of the trainees (62%) used a laptop to participate in the learning process. Students face various problems, such as lack of sufficient means of subsistence (51%), health problems (47%), internet connectivity problems (32%) and lack of suitable conditions for learning at home (21%). Students from small settlements and those with incomes below the poverty line face serious challenges during the pandemic.
The declared state of emergency and the measures taken against the spread of coronavirus by gover... more The declared state of emergency and the measures taken against the spread of coronavirus by governments have increased Internet shopping. All companies, regardless of size and type of business activity, had to adapt their business models to the new circumstances through transformation of their business processes and offering products or services tailored to the changing customer behavior. This study aims to analyze the peculiarities of online sales during the COVID-19 health crisis via the integration of classic and modern data analysis methods. The purpose of the paper is to identify the main factors determining user behavior and examine their impact on customer satisfaction in e-commerce. The survey method and structural equation modeling (SEM) were used to recognize the dependencies between variables from the online users’ perspective. The satisfaction determinants indicated and described in the paper affect differently the perceived value for the customers. As this value is subj...
In order to help curb the spread of the COVID-19 pandemic, this paper develops a multi-attribute ... more In order to help curb the spread of the COVID-19 pandemic, this paper develops a multi-attribute decision-making framework for COVID-19 vaccine evaluation based on their major clinical characteristics and efficacy. Firstly, a new multi-criteria Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) modification has been constructed in an interval-valued Fermatean fuzzy (IVFF) environment, improving the shortcomings of traditional TOPSIS. Secondly, a new conceptual framework for static and dynamic evaluation of COVID-19 vaccines has been built. The proposed methodology incorporates a variety of crisp and fuzzy MCDM methods. The analysis of the results of two practical examples shows that the new framework for vaccine comparison is feasible and effective, and finally, some recommendations for enhancement of government anti-COVID-19 strategies are suggested.
In order to assess the impact of the COVID-19 pandemic on learning process of students in the Sou... more In order to assess the impact of the COVID-19 pandemic on learning process of students in the South-Central region of Bulgaria, an online survey was conducted at the University of Plovdiv Paisii Hilendarski during the period from November 17 to December 5, 2020. The questionnaire was created via Google Forms and the link was shared with the students through social media (Facebook pages of the University and Faculty of Economics and Social Sciences). A total of 134 questionnaires were correctly completed during the study period. For analysis of the collected data the percentage distribution is calculated and statistical methods and machine learning methods are applied. During the lockdown, all respondents are trained remotely, with about 60% (80) of the learners learning entirely in an electronic environment. Most of the trainees (62%) used a laptop to participate in the learning process. Students face various problems, such as lack of sufficient means of subsistence (51%), health problems (47%), internet connectivity problems (32%) and lack of suitable conditions for learning at home (21%). Students from small settlements and those with incomes below the poverty line face serious challenges during the pandemic.
This research aims to analyse the applications of IoT in agriculture and to compare the most wide... more This research aims to analyse the applications of IoT in agriculture and to compare the most widely used IoT platforms. The problem of determining the most appropriate IoT system depends on many factors, often expressed by incomplete and uncertain estimates. In order to find a feasible decision, this study develops a multi-criteria framework for IoT solution selection in a fuzzy environment. In the proposed framework, a new modification of the Multi-Attribute Border approximation Area Comparison (MABAC) method with a specific distance measure via intuitionistic fuzzy values has been presented as a decision analysis method. The new technique is more precise than existing crisp and fuzzy analogues, as it includes the three components of intuitionistic numbers (degree of membership, degree of non-membership and hesitancy degree) and the relationships between them. The effectiveness of the new decision-making framework has been verified through an illustrative example of ranking IoT pla...
In this paper, we present a new fuzzy methodology for early students' failure detection. High... more In this paper, we present a new fuzzy methodology for early students' failure detection. High school background, subjects studied in the university and activities in learning management systems were determined to be the factors influencing students' performance. After selection of the impact factors of students' assessment, we convert linguistic evaluations into fuzzy numbers and employ multi-criteria methods for educational data processing. In two practical examples, the aggregate students' scores were calculated by using fuzzy multi-criteria algorithms. The obtained students' ranking helps instructors during the semester to detect students who will drop out the course and to plan additional learning activities for these students. In the future, we plan on analysing students' data from different university's courses and majors and mining several academic years in order to create a reliable assessment index for early prediction of students' failure.
Proceedings of the 9th Balkan Conference on Informatics, 2019
Small and medium-sized enterprises represent 99% of all enterprises in the EU and in Bulgaria and... more Small and medium-sized enterprises represent 99% of all enterprises in the EU and in Bulgaria and generate about two thirds of gross value added. This makes small business competitiveness of utmost importance for the economies of both the Union and the country. Applying business intelligence in the decision making process of such companies could enhance their receptivity and adaptivity towards market changes and could create a new organizational culture aimed at continuous improvement. The objective of the presented research is to identify the current state and problems related to the application of business intelligent systems in small and medium enterprises in South Central Bulgaria (South Central Statistical Area), to explain the reasons for the status of Bulgarian companies, and to develop recommendations for efficient use of the business intelligence by small and medium-sized business.
The purpose of the paper is to systematically analyze the capabilities of big data technology to ... more The purpose of the paper is to systematically analyze the capabilities of big data technology to solve important problems in electronic commerce. The role of big data as one of the central priorities in modern information technologies for online sellers and buyers is underlined. Big data methods to improve the basic functional areas of e-commerce: marketing, payments, supply chain, and management are described. A new model for automation of key business processes in e-commerce through new technology is presented. The model is verified using practical examples of e-commerce activities. The process of e-commerce modernization requires additional infrastructure, new methods and modern software for better data organizing, customer personalization and improved decision making.
Membership functions are a key concept in fuzzy set theory and their correctness and precision ar... more Membership functions are a key concept in fuzzy set theory and their correctness and precision are essential for the accuracy of obtained results. This article discusses the use of Bezier curve to construct a membership function. Based on the frequency distribution of data by minimization, the coordinate formulas of the control points that define the curve are derived. Use of the described membership function is illustrated by an example. These formulas are applied to bispectral index data sets in order to compare with other published method. MSC: 03E72, 65D05, 65D10, 65D15 keywords: Fuzzy set, Membership function, Bezier curve, Least-squares minimization ∗Accepted for publication on March 5, 2018 †[email protected] Faculty of Economics and Social Sciences, University of Plovdiv Paisii Hilendarski, 24 ”Tzar Assen” str., Plovdiv, Bulgaria ‡[email protected] Faculty of Economics and Social Sciences, University of Plovdiv Paisii Hilendarski, 24 ”Tzar Assen” str., Plovdiv, Bulgari...
Despite the worldwide physical closing of educational institutions due to the pandemic of COVID-1... more Despite the worldwide physical closing of educational institutions due to the pandemic of COVID-19 in the spring of 2020, the learning process was not interrupted. Learning management systems and digital tools for online collaboration ensured a safe distance and continuity of educational activities. However, the rapid transition to remote learning in electronic environment has created a number of challenges in higher education. In order to derive longterm benefits from the changes in the way of teaching and examining, the paper explores the possibilities of IoT technology for continuous monitoring and flexible management of the learning process. The proposed framework for IoT application in educational activities will facilitate the adaptation of studying process at universities to the new circumstances.
In accordance with a presented classification of the types design procedures, a short overview ha... more In accordance with a presented classification of the types design procedures, a short overview has been provided, of the latest software for the design of mechanisms. The present overview shows that the theoretical basis for developing every design system leads to the construction of a formal mathematical model of a set of mechanism structures with a greater or smaller degree
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