Camelia Delcea

Bucharest Academy of Economic Studies | ASE · Department of Computer Science and Cybernetics

Social media has become a preeminent medium of communication during the early 21st century, facilitating dialogue between the political sphere, businesses, scientific experts, and everyday people. Researchers in the social sciences are focusing their attention on social media as a central site of social discourse, but such approaches are hampered b...

Agent-based modeling (ABM) has emerged as a distinct and innovative paradigm offering an alternative to conventional modeling techniques which often rely on equation-based representations to depict specific events or phenomena [...]

Given the high amount of information available on social media, the paper explores the degree of vaccine hesitancy expressed in English tweets posted worldwide during two different one-month periods of time following the announcement regarding the discovery of new and highly contagious variants of COVID-19—Delta and Omicron. A total of 5,305,802 CO...

The uncertainty of the environment, the complexity of economic systems, both at the national and global economy levels, and the digital age and artificial intelligence draw attention to the existence or appearance of systemic, disruptive phenomena that can appear and propagate in different forms, producing effects that can turn into economic crises...

The airplane boarding problem is discussed in this chapter by taking into account both the transport cost reduction and the risk assessment generated by the COVID-19 pandemic, while accounting for the passengers’ comfort while boarding. For addressing the airplane boarding problem, an agent-based approach is created and used for simulating the pass...

In this chapter, a basic presentation of the project management is made from the perspective of the operations research, having the purpose of familiarizing the reader with the terms used and with the current approach in determining the time needed for completing a complex project. Due to its numerous advantages, it has been observed that the grey...

This chapter is dedicated to the application of the grey relational analysis in the public opinion mining. Due to the complex economic and social situation the entire mankind has passed in the last few years since the occurrence of the COVID-19 pandemics, the chapter features an application on the public opinion assessment in connection with the CO...

Over the years, the grey systems theory has succeeded in providing to the research community a framework for dealing with partially known information through a series of specific methods. Besides the advancements made in various research areas, the grey systems theory has been rapidly adopted in the economic and social sciences area for solving bot...

Supplier selection is a multi-attribute decision-making (MADM) problem largely discussed in the scientific literature. The supplier selection problem has evolved from a commodity-based operational decision approach—which considers mainly aspects related to economic issues, described through a series of strategic performance measures (such as cost,...

The present chapter has been dedicated to the hybrid approaches in the scientific literature in which grey systems theory has been used along with other intelligent artificial techniques for modeling different situations related to the economics and social sciences field. In terms of grey hybridization, four main theories have been chosen, namely f...

The issues discussed under the programming umbrella are various and have attracted, over time, the interest of the researchers from all around the world. In the case of linear programming, both the objective function and the constraint conditions are linear functions. With the arise and the development of the grey systems theory, the use of the gre...

Various sentiment lexicons have been created over time for helping researchers and other interested parties in better determining the sentiments associated with a message or a text. The sentiment lexicons contain words and sequences of words (called tokens) pre-classified in positive, negative and neutral categories. Some of the lexicons provide ev...

The author’s first name in chapter “Companies Image Evaluation Using Social Media and Sentiment Analysis” was incorrect in the initially published version. This is now corrected and is given as Liviu-Adrian Cotfas.

The economic systems are basically grey systems due to their components and to their interactions which enable the occurrence of uncertainty. First, the human component plays an important role as a consequence of its usually unpredictable and sometimes irrational behavior, a situation strictly related to the way the humans are thinking and acting....

Recent studies have shown that based on informal communication, made from one user to another, certain opinions regarding the activity of a company can be formed, with long-term influence on consumers, perception on its image. By focusing on the Millennial generation, this research presents its main characteristics and examines the consumer’s behav...

This paper aims to model the covariance of financial assets using neutrosophic fuzzy numbers. Two main concepts are discussed and used, namely the neutrosophic covariance of the financial assets and the independent neutrosophic portfolios. In terms of methodology, a three-step approach is proposed with the purpose of identifying the independent neu...

The coronavirus pandemic has undoubtedly been one of the major recent events that have affected our society at the global level. During this period, unprecedented measures have been imposed worldwide by authorities in an effort to contain the spread of the disease. These measures have led to a worldwide debate among the public, occurring not least...

Time is crucial in public buildings evacuation during an emergency as it can have a direct impact on the number of people injured, or on the gravity of the injuries. Designing emergency evacuation plans or proposing various alternatives to public buildings’ design, by considering the dynamic behavior of pedestrians, has the potential to reduce the...

The coronavirus pandemic has forced authorities to take unprecedented measures, including the temporary closure of business and the instauration of national and regional lockdowns. The educational system, one of the key components of the society, has also been disrupted, as many schools and universities have moved their courses online for prolonged...

The cruise ship industry has faced in recent years a continuous increase in the number of passengers, reaching 28.5 million passengers in 2018, 60.11% more than in 2009. In this context, the research literature has acknowledged the key role played by the passengers' safety and has considered different aspects when dealing with the ship evacuation p...

While social media platforms can serve as public discussion forums of great benefit to democratic debate, they can also become a source of disinformation, bullying, hate speech, and a setting for fruitless polemics. In extreme cases, discourse originating in or propagated through social media can stoke political polarization and partisanship, with...

Many airlines instituted social distancing practices to keep passengers safe during the pandemic. The practices include keeping the middle seats empty, reducing the number of passengers taking an apron bus from the terminal to the airplane, and prescribing that passengers maintain 1 m social distance of separation from other passengers in the aisle...

Vaccination has been proposed as one of the most effective methods to combat the COVID-19 pandemic. Since the day the first vaccine, with an efficiency of more than 90%, was announced, the entire vaccination process and its possible consequences in large populations have generated a series of discussions on social media. Whereas the opinions trigge...

The integration of renewable energy sources into the energy system requires both new investment in network infrastructures, and the introduction of new models of energy management. In this framework, new structures of collaborations were born: the aggregator is one of them. It involves grouping different players of the power system, acting, however...

The COVID-19 pandemic has produced changes in the entire aviation industry, including adjustments by airlines to keep the middle seats of airplanes empty to reduce the risk of disease spread. In this context, the scientific literature has introduced new metrics related to passengers’ health when comparing airplane boarding methods in addition to th...

The paper explores the usage of agent-based modeling in the context of large event halls evacuation during music festivals and cultural events. An agent-based model is created in NetLogo 6.2.2 for better representing the human behavior when involved in such situations. A series of characteristics have been set for the agents in order to preserve th...

We provide a mixed-integer programming model (MIP) to assign airplane passengers to seats while preserving two types of social distancing: the distance from the passengers’ seats to the aisle and the distance among groups of passengers who are not travelling together. The method assigns passengers travelling within a family group to seats near othe...

Wearing a mask by the general public has been a controversial issue from the beginning of the COVID-19 pandemic as the public authorities have had mixed messages, either advising people not to wear masks if uninfected, to wear as a protective measure, to wear them only when inside a building/room with insufficient air flow or to wear them in all th...

The occurrence of the novel coronavirus has changed a series of aspects related to people's everyday life, the negative effects being felt all around the world. In this context, the production of a vaccine in a short period of time has been of great importance. On the other hand, obtaining a vaccine in such a short time has increased vaccine hesita...

Airlines and researchers have been working to reduce the health risk to passengers from the novel coronavirus SARS-CoV2. Recent literature indicates that the Reverse Pyramid boarding method provides a lower health risk than other boarding methods using a limited number of boarding groups, while keeping the middle seats empty. With a primary objecti...

The purpose of this paper was to model, with the help of neutrosophic fuzzy numbers, the optimal financial asset portfolios, offering additional information to those investing in the capital market. The optimal neutrosophic portfolios are those categories of portfolios consisting of two or more financial assets, modeled using neutrosophic triangula...

The social distancing imposed by the novel coronavirus, SARS-CoV-2, has affected people’s everyday lives and has resulted in companies changing the way they conduct business. The airline industry has been continually adapting since the novel coronavirus appeared. A series of airlines have changed their airplane boarding and passenger seat allocatio...

Purpose The airline industry has been significantly hit by the occurrence of the new coronavirus SARS-CoV-2, facing one of its worst crises in history. In this context, the present paper analyses one of the well-known boarding methods used in practice by the airlines before and during the coronavirus outbreak, namely back-to-front and suggests whic...

The rapid growth and use of the online social networks have generated an increasing interest in different research areas, while a series of studies have shown the importance of the consumers’ influence in these networks on other users’ decisions and attitudes. In this context, the current research focuses on the recycling habits’ influences that mi...

The coronavirus outbreak has brought unprecedented measures, which forced the authorities to make decisions related to the instauration of lockdowns in the areas most hit by the pandemic. Social media has been an important support for people while passing through this difficult period. On November 9, 2020, when the first vaccine with more than 90%...

The onset of the novel coronavirus SARS-CoV2 has changed many aspects of people's economic and social activities. For many airlines, social distancing has reduced airplane capacity by one third as a result of keeping the middle seats empty. Additionally, social distancing between passengers traversing the aisle slows the boarding process. Recent li...

Social distancing resulting from the new coronavirus (SARS-CoV2) has disrupted the airplane boarding process. Social distancing norms reduce airplane capacity by keeping the middle seats unoccupied, while an imposed aisle social distance between boarding passengers slows the boarding. Recent literature suggests the Reverse Pyramid boarding method i...

Airlines have recently instituted practices to reduce the risk of their passengers becoming infected with the novel coronavirus (SARS-CoV-2). Some airlines block their airplanes’ middle seats to preserve social distancing among seated passengers. In this context, we present six new boarding methods and compare their performance with that of the two...

This paper addresses the airplane passengers’ seat assignment problem while practicing social distancing among passengers. We proposed a mixed integer programming model to assign passengers to seats on an airplane in a manner that will respect two types of social distancing. One type of social distancing refers to passengers being seated far enough...

While the literature contains many slightly different definitions for the image of a company, they all put great emphasis on its importance. Many of the messages posted on social media networks nowadays contain strong sentiment and emotion indications regarding almost any topic, therefore turning them into a rich and almost real-time data source fo...

The increase in consumerism due to population growth, excessive advertising and the constant encouragement of buying behavior by advertising media and opinion formers comes with side effects for the environment and public health if it is not properly supported by a sustainable selective waste collection process. In this context, the paper aims at d...

Social distancing reduces the risk of people becoming infected with the novel coronavirus (SARS-CoV-2). When passengers are transported from an airport terminal to an airplane using apron buses, safe social distancing during pandemic times reduces the capacity of the apron buses and has led to the practice of airlines keeping the middle seats of th...

The novel coronavirus (SARS-CoV-2) has imposed the need for a series of social distancing restrictions worldwide to mitigate the scourge of the COVID-19 pandemic. This applies to many domains, including airplane boarding and seat assignments. As airlines are considering their passengers' safety during the pandemic, boarding methods should be evalua...

As it is well acknowledged that the electoral system is one of the fundamental rocks of our modern society, the behavior of electors engaged in a voting system is of the utmost importance. In this context, the goal of the study is to model the behavior of voters in a first-past-the-post system and to analyze its consequences on a party system. Amon...

Purpose The article proposes a new method of strategic analysis. The method was called the grey portfolio analysis method. The presented method is complementary to the popular BCG matrix. The use of the grey portfolio analysis method enables to make a dynamic portfolio analysis for data with a high level of uncertainty. Design/methodology/approach...

As the evacuation problem has attracted and continues to attract a series of researchers due to its high importance both for saving human lives and for reducing the material losses in such situations, the present paper analyses whether the evacuation doors configuration in the case of classrooms and lecture halls matters in reducing the evacuation...

Due to the increase of the amount of electrical and electronical equipment waste (e-waste), the understanding of individual consumers’ main decision triggers represents a key point in increasing the quantity of recycled e-waste. A series of studies from the literature have shown a positive relationship between the consumers’ attitude, awareness, se...

This paper proposes a method for reducing the time to complete the boarding of a two-door airplane when its passengers are transported from the airport terminal to the airplane using two apron buses. In contrast to other methods that assign passengers to apron buses, our method considers groups of passengers traveling together (e.g. families). In p...

This paper studies the problem of tangible assets acquisition within the company by proposing a new hybrid model that uses linear programming and fuzzy numbers. Regarding linear programming, two methods were implemented in the model, namely: the graphical method and the primal simplex algorithm. This hybrid model is proposed for solving investment...

Human behavior and the environment’s characteristics have proven to play an important role within the evacuation process as they can facilitate a shorter evacuation time. The collaborative classrooms represent a now-a-days architectural trend as, when compared to the classical classrooms, they provide a friendlier space for learning, allowing stude...

Bad decisions have harmful effects on the quality of human life and an increase of their duration expands these undesirable effects. Systematic bad decisions related to dividend policy can affect the investors’ quality of life in the long-term. We propose an agent-based model for the estimation of the duration of systematically making bad decisions...

This paper studies the problem of neutrosophic portfolios of financial assets as part of the modern portfolio theory. Neutrosophic portfolios comprise those categories of portfolios made up of financial assets for which the neutrosophic return, risk and covariance can be determined and which provide concomitant information regarding the probability...

This paper investigates the time to complete the boarding of a partially occupied two-door airplane when its passengers are transported from the airport terminal to the airplane using two apron buses. We propose a greedy method that assigns each passenger to a particular apron bus based on the passengers’ airplane seat assignments. This greedy appr...

The use of apron buses for transporting passengers from the airport terminal to the airplane has become common practice for a series of airports worldwide. Airline companies have become increasingly aware of this practice and have added information to their boarding passes to suggest the airplane door passengers should use while boarding the airpla...

The use of apron buses has become a common practice at many European airports. Previous studies related to airplane boarding rarely apply when apron buses are used, leaving airlines with no well-researched option except to use the random boarding method. In this paper, we test the time to complete boarding a two-door airplane using various boarding...

Apron buses are widely employed by European airlines to transfer passengers from airport terminals to airplanes. However, the vast majority of current boarding methods are designed for use with jet-bridges and one-door boarding of airplanes and thus are not well suited for apron buses and passengers boarding simultaneously through both a front door...

This research sets the basis for modeling the performance indicators of financial assets using triangular neutrosophic fuzzy numbers. This type of number allows for the modeling of financial assets performance indicators by taking into consideration all the possible scenarios of their achievement. The key performance indicators (KPIs) modeled with...

Educational properties have recorded an average of 4980 structure fires between 2011 and 2015 according to US National Fire Protection Association. It has been determined that four out of five fires in schools have occurred between 6 a.m. and 6 p.m., when pupils were around. Even though the percentage of structure fires in educational properties ha...

This paper develops a Mamdani fuzzy logic system (FLS) that has stochastic fuzzy input variables designed to identify cash-flow deficits in bank lending policies. These deficits do not cover the available cash-flow (CFA) resulting from the company's operating activity. Thus, due to these deficits, solutions must be identified to avoid companies' fi...

Social influence has a positive impact on the purchase intention for eco-friendly products along with other subjective and objective aspects related to environmental attitude, product attitude, and subjective and objective knowledge. Also, exposure to media has been proven to have a significant positive affect on environmental attitude, with effect...

As companies operate in a competitive environment, where the struggle for survival on the market is rather tough, the top management face new challenges to identify methods, and even techniques, which allows it to select from the market those assets that provide an optimal ratio between the acquisition cost and the economic performance. In this con...

As time is crucial in the human evacuation process during an emergency situation, several aspects related to how the humans involved in such a process act have been studied over the time, underlying that the humans’ behavior is rather unpredictable and depends on social background, emotions, the degree of familiarity with the environment, age, gend...

Research related to creating new and improved airplane boarding methods has seen continuous advancement, in recent years, while most of the airline companies have remained committed to the traditional boarding methods. Among the most-used boarding methods, around the world, are back-to-front and random boarding with and without assigned seats. Whil...

Seat and aisle interferences are assumed to be linked with a prolonged boarding time along with several other aspects related to airplane boarding such as: luggage handling, luggage distribution inside the cabin, number of passengers, passengers’ physique characteristics, group behavior, seat selection, aircraft occupancy, aircraft design, etc. Bas...

Boarding is one of the major processes of airplane turnaround time, with a direct influence on the airline companies’ costs. From a sustainable point of view, a faster completion of the boarding process has impact not only on the airline company’s long-term performance, but also on customers’ satisfaction and on the airport’s possibility of offerin...

The airplane turnaround time costs money to the airline companies and, over the years, it has been determined that the best way to reduce it is by using efficient boarding strategies. Many boarding strategies have been proposed but a consensus as to which is the best method has not been reached yet. The aim of this paper is to gather and test all t...