Stelios Tsafarakis

• Phd
• Professor (Associate) at Technical University of Crete

Customer segmentation, a critical strategy in marketing, involves grouping consumers based on shared characteristics like age, income, and geographical location, enabling firms to effectively establish different strategies depending on the target group of customers. Clustering is a widely utilized data analysis technique that facilitates the identi...

The rapid shift to online education during the COVID-19 crisis has presented both challenges and opportunities for educators worldwide. This paper aims to analyze free-text comments from instructors at Greek Higher Education Institutions (HEIs), gathered during a quantitative survey on the impact of the intensive use of ICT during the lockdown. Top...

Online review sites play a crucial role in shaping consumer purchasing decisions, making the analysis of customer feedback essential for businesses. Given the complexity of these reviews, often including both quantitative and qualitative data, advanced analytical frameworks are necessary. To this end, this paper introduces an integrated framework f...

The aim of this study is to apply a multi-objective product line optimization approach for reducing food waste while balancing profit and buyer’s welfare. The proposed approach is based on a Non-dominated Sorting Genetic Algorithm II (NSGA-II) and it is used for addressing the NP-hard problem of product line redesign, by optimizing both economic an...

This study addresses the critical question of how AI and algorithmic HRM can be deployed to reconfigure HR practices for enhancing workforce development. Employing a novel methodological approach, this study leverages a dataset from an online employer review platform, incorporating employee ratings and textual feedback across multiple HR criteria....

As online journalism is expanding, the requirements of the readers are increasing. The need for engaging and sustaining online users/readers is more important than ever. This study aims to investigate the level of readers’ satisfaction towards the services of news websites in Greece. Through a market survey 357 responses to a specifically designed...

The aim of this study is to investigate the challenges and opportunities faced by university instructors in using ICT technologies during the COVID-19 pandemic. The study utilized a dataset collected through an online survey of university instructors in Greece during the lockdown and applied advanced topic modelling techniques using Large Language...

Research indicates that the importance the social validity of an appropriate principal-selection method may have, as well as the importance of the parameters that affect it, is directly related to the acceptance or reaction of the candidates to it and their job satisfaction. The aim of this quantitative research is to examine and present the candid...

Theatrical performance constitutes a complicated way for students to express and to communicate with each other, since it targets both various artistic and educational goals. Even though it constitutes a top moment of students’ expression, several students do not feel comfortable when participating in such cultural activities, as performance anxiet...

We presented an MMR methodology focused on customer feedback, able to combine information from comments and ratings to create insights for VoC program support. Our methodology can be integrated into a system with data crawling, processing and analysis tools. Our method was awarded with the "Best Methodoloy Award".

During the pandemic, the Higher Education Institutions of Greece used Information and Communications Technologies (ICT) to an unprecedented degree to respond to the requirements of distance education and research work. The aim of this article is to present the main results of a nationwide quantitative survey that involved 1183 participating univers...

The aim of the current paper is to introduce a global optimization algorithm, inspired from the survival strategies of flying foxes during a heatwave, called as Flying Foxes Optimization (FFO). The proposed method exploits a Fuzzy Logic (FL) technique to determine the parameters individually for each solution, thus resulting in a parameters-free op...

Product design constitutes a critical process for a firm, which if not implemented effectively it may even question its viability. The optimal product line design is an NP-hard problem, where a company aims at designing a set of products that will optimize a specific objective. Whilst Tabu Search (TS) has effectively solved a large number of combin...

Product design constitutes a critical process for a firm to stay competitive. Whilst the biologically inspired Clonal Selection Algorithms (CSA) have been applied to efficiently solve several combinatorial optimization problems, they have not yet been tested for optimal product lines. By adopting a previous comparative analysis with real and simula...

The aim of this paper is to present a method that uses computational intelligence techniques to classify students according to the principles of differentiated instruction. A clustering algorithm based on particle swarm optimization is applied to two sets of data emerging from the holistic assessment of the student's particular characteristics and...

Designing a successful product line is a critical decision for a firm to stay competitive. By offering a line of products, the manufacturer can maximize profits or market share through satisfying more consumers than a single product would. The optimal Product Line Design (PLD) problem is classified as NP-hard. This paper proposes a Fuzzy Self-Tunin...

This paper introduces a new method called the Mayfly Algorithm (MA) to solve optimization problems. Inspired from the flight behavior and the mating process of mayflies, the proposed algorithm combines major advantages of swarm intelligence and evolutionary algorithms. To evaluate the performance of the proposed algorithm, 38 mathematical benchmark...

The optimal product line design is one of the most critical decisions for a firm to stay competitive, since it is related to the sustainability and profitability of a company. It is classified as an NP-hard problem since no algorithm can certify in polynomial time that the optimum it identifies is the overall optimum of the problem. The focus of th...

Introduction: Public Transport users have diverse mobility needs and preferences on how to meet those needs. While this is consistent with typical standards for both academic scholars and practitioners, less is known about the structure of these preferences, how different they are, especially with regard to innovations in Public Transport. Previous...

The presentation focuses on the replacement of the ordinal-type qualitative satisfaction data with positive real numbers and on the choice of three numbers as qualitative anchors for the exclusion-crossover-inclusion thresholds when applying the fsQCA

Measuring customer satisfaction is a key element for modern businesses as it can significantly contribute to a continuing effort of service quality improvement. In order to meet customer expectations and achieve higher quality levels, airlines need to develop a specific mechanism of passenger satisfaction measurement. In this paper we show how MUSA...

The optimal product line design is an NP-hard optimization problem in marketing that involves a number of decisions, such as product line length and configuration. Simulated annealing constitutes the best performing approach so far, but with extremely large running times. In the current study simulated annealing is hybridized with an evolutionary a...

Despite the longstanding recognition of the importance of product assortment planning (PAP), existing literature has failed to provide satisfactory solutions to a great deal of problems that reside in this area of research. The issue of optimal assortment planning in the retail sector becomes even more important in periods of economic crisis, as re...

The product life cycle of cars is becoming shorter and carmakers constantly introduce new or revised models in their lines, tailored to their customer needs. At the same time, new car model design decisions may have a substantial effect on the cost and revenue drivers. For example, although a new car model configuration with component commonality m...

In this paper we introduce a new descriptor, the Human Constrained Pixel Change History (HC-PCH), which is based on Pixel Change History (PCH) but focuses on the human body movements over time. We propose a modification of the conventional PCH which entails the calculation of two probabilistic maps, based on human face and body detection respective...

This article presents an artificial intelligence-based solution to the problem of product line optimization. More specifically, we apply a new hybrid particle swarm optimization (PSO) approach to design an optimal industrial product line. PSO is a biologically-inspired optimization framework derived from natural intelligence that exploits simple an...

Market segmentation is a broadly recognized concept in strategic marketing and planning. Although K-means cluster analysis has been traditionally used as a means to segment markets during the last 50 years, the results have often been reported to be less than satisfactory. This paper develops and introduces a new nature-inspired mechanism, called P...

The optimal product design is an NP-hard marketing optimization problem, in which a firm aims at the maximization of its market share or profit. A manager that deals with the problem has to decide on a number of issues, such as how to simulate the consumer choice process, which optimization algorithm to apply, and how to model the competitors' reta...

Firms need to continuously develop new products or redesign their existing ones, due to the intense competition they are facing, as well as the rapidly changing economical and sociopolitical environment. In this context, consumer behaviour modelling has become an important and inextricable part of successful new product development during the last...

This article introduces nature-inspired modeling to strategic service management. It determines optimal service diversification through an evolutionary mechanism of natural selection and population genetics as well as a model of cooperative behavior and collective intelligence in swarms. Specifically, we design and implement Genetic and Particle Sw...

Lack of adaptability within WorkFlow Management Systems (WFMS) has been early identified as one of their limitations. WFMS suffer from disadvantages such as not supporting the dynamic incorporation/modification of process models and poor adaptability of process models at runtime. The static workflow definition and its passive interpretation does no...

The product life cycle of cars is becoming shorter and carmakers constantly introduce new or revised models in their lines, tailored to their customer needs. At the same time, new car model design decisions may have a substantial effect on the cost and revenue drivers. For example, although a new car model configuration with component commonality m...

The extremely high costs associated with the commercial failure of a new product, stresses the importance of a model that will effectively forecast the market penetration of a product at the design stage. The purpose of our study is to discover heuristics that will better explain market share, an issue of considerable concern to industry, which als...

The optimal product line design problem consists of predicting the acceptance of new products in the market, prior of the actual production phase. It requires a unique blend of techniques and resources as it deals with multiple parameters and hard optimization problems. This paper proposes a service oriented architecture which outlines the basic fe...

The high cost of a product failure makes it imperative for a company to assess the market penetration of a new product at its early design. In this context, the Optimal Product Line Design problem was formulated thirty five years ago, and remains a significant research topic in the area of quantitative marketing until today. In this chapter we prov...

This chapter emphasizes on the major components under which MCDA applications in marketing and e-commerce have been developed and describes characteristic examples of research works that apply MCDA methodologies in marketing and e-commerce. The chapter is divided into two main sections separating the MCDA applications in the marketing discipline fr...

Designing optimal products is one of the most critical activities for a firm to stay competitive. Except for genetic algorithms, previous approaches that solve the optimal product line design problem provide the decision maker with a single best solution. Furthermore, they assume a static market, in which the incumbent firms will not respond to the...

UTARec, a Recommender System that incorporates Multiple Criteria Analysis methodologies is presented. The system's performance and capability of addressing certain shortfalls of existing Recommender Systems is demonstrated in the case of movie recommendations. UTARec's accuracy is measured in terms of Kendall's tau and ROC curve analysis and is als...

Designing optimal product lines is essential for any firm to stay competitive. Whereas a large number of optimization algorithms have been applied for solving the problem, most of them adopt the first choice rule to simulate the consumer's choice process. Researchers avoid using probabilistic choice models, such as the logit, since they tend to pro...

Market simulators assist managers in product design and pricing decisions, through advanced heuristic algorithms for consumer buying behavior modeling. We propose a model for use in such systems, which combines the effective incorporation of the two critical properties a simulator should theoretically reflects, with exceptionally performance in act...