Evolutionary fuzzy cognitive maps: technique development and application in modeling, control and forecasting of dynamic systems

This dissertation concerns the investigation, development and application of computational and artificial intelligence methodologies for the modelling, simulation, control and forecasting of complex, non-linear, dynamic systems behavior. At first, the inference mechanism of fuzzy cognitive maps (FCM) is improved with the incorporation of an innovative convex algorithm used in case of multiple parallel external stimulations while the evolution strategies are applied for the development of a new adaptive-learning property and function through a training procedure based on examples, which indicates the automatic, dynamic and holistic design of FCM. As an indicative application, a stock market model is developed, a highly non-linear synamic system, including 34 quantitative indices ans qualitative factors and 54 cause-effect relationships that formulate 5 subsystems composing the whole model. The experimental results are among the best returns reported n the international bibliography and notify in advance the further succesful application of the presented methodology.Η διατριβή αυτή ασχολείται με τη διερεύνηση, την ανάπτυξη και την εφαρμογή μεθοδολογιών υπολογιστικής και τεχνητής νοημοσύνης για την μοντελοποίηση, προσομοίωση, έλεγχο και πρόβλεψη της συμπεριφοράς πολύπλοκων, μη-γραμμικών , δυναμικών συστημάτων. Καταρχήν βελτιώνεται η λειτουργία των ασαφών εννοιολογικών γραφών (FCM) με την εισαγωγή ενός νεωτερικού κυρτού σχήματος συμπερασμού για περιπτώσεις πολλαπλών ταυτοχρόνων εξωτερικών διεγέρσεων ενώ χρησιμοποιούνται οι εξελικτικές στρατηγικές για την ανάπτυξη καινοφανούς προσαρμοστικής-μαθησιακής ιδιότητας και λειτουργίας τους μέσω διαδικασίας εκπαίδευσης βάσει παραδειγμάτων, η οποία υποδυκνύει την αυτόματη, δυναμική και εν τω συνόλω σχεδίαση των FCM. Ως εφαρμογή αναπτύσσεται ένα μοντέλο της χρηματιστηριακής αγοράς, ως χαρακτηριστικό μι-γραμμικό δυναμικό σύστημα, με 34 ποσοτικούς δείκτες και ποιοτικούς παράγοντες και 54 σχλεσεις αιτίου-αιτιατού οι οποίες συνθέτουν 5 υποσυστήματα τα οποία συναποτελούν το μοντέλο. Τα αποτελέσματα συγκαταλέγονται στις καλύτερες αποδόσεις της διεθνούς βιβλιογραφίας, και προδιαγράφουν την περαιτέρω επιτυχή εφαρμογή της προκείμενης μεθοδολογίας

Risk-Acceptance Criteria in Occupational Health and Safety Risk-Assessment—The State-of-the-Art through a Systematic Literature Review

The utilization of risk acceptance criteria (RAC) can help a business to judge whether the risk level concerning any process involved in its working environment is acceptable or not, especially when the risk has a significant societal impact. Thus, the main intention of this study is to make known the current state-of-the-art concerning RACs and to propose new interpretations of it by surveying, for first time, the scientific literature about the RACs associated with the occupational health and safety (OHS) risk-assessment methodologies (RAA). A second objective of this work is the attainment of a prediction for the evolution of the quantity of the publications concerning OHS-RACs, and a third one is the derivation of an algorithm (via a flow-chart) in order to illustrate the process of the formation of new OHS-RACs. The work consists of two parts, (a) exploring and presenting methods of developing RACs in OHS; (b) classifying, analyzing, and benchmarking relevant published scientific articles by surveying the Scopus data base with proper search-hints, through a time interval of 20 years (January2000–December 2019). The review has defined a plethora of RAC-papers with reference to OHS, which is a remarkable percentage in comparison with the other fields aggregated, and this outcome proves that the issue of utilizing RACs is fundamental for the field of OHS. Additionally, it has been deduced that, day after day, there is an increasing tendency for the scientific community to develop and use RACs in the field of occupational safety, as this is evident by their frequent reference to the risk analysis and assessment (RAA) process. Our specific research methodology has been compatible with the PRISMA protocol. A prediction for the evolution of the quantity of the OHS-RAC publications is also given by confirming the Poisson stochastic process. Finally, we propose a generic guideline framework that can contribute to the establishment of new empirically-generated OHS-RACs

Blending E-Learning with Hands-on Laboratory Instruction in Engineering Education: An Experimental Study on Early Prediction of Student Performance and Behavior

Among the various information sources exploited for the improvement of the learning process and outcomes, access and usage data from the interaction of students with e-learning platforms along with (past) student performance data are established as the two most meaningful and informative groups of variables. In the present study, these two groups of variables are jointly investigated as to their efficiency in providing both accurate and early prediction of student performance and behavior. The relevant educational intervention is designed and implemented as a quasi-experiment with undergraduate Electrical and Electronics Engineering students, under a novel approach that blends e-learning (asynchronous e-study and synchronous e-assessment) with a hands-on laboratory component. Can educational data mining algorithms provide both early and accurate prediction of student performance and student behavior under this scenario? If yes, how much prediction accuracy can be traded for prediction timeliness in order to allow a proactive class instructor take supportive measures for weak/marginal students, implementing a ‘self-contained’ strategy? To answer these questions, real data from the interaction of 3 academic year student cohorts with moodle are collected and analyzed. Results reveal that the proposed scenario can afford both accurate and early prediction of student performance and behavior, on the basis of data collected within the running academic term. The middle of the term is indicated as the earliest time point for getting meaningful predictions. Moreover, clustering of the data in the selected feature space reveals a consistent and therefore exploitable behavior of students along the term

International Management System Standards Related to Occupational Safety and Health: An Updated Literature Survey

The implementation of an international management system (IMS) in any organization (or part thereof) creates an efficient framework regarding the sustainable development and the review of processes required to manage occupational safety and health (OSH) efficaciously. Moreover, Occupational Safety and Health Management System (OSHMS) standards identify requirements regarding OSH management systems, with the aim of enabling an organization to adopt dynamic policy and objectives that take into consideration lawful requirements relating to OSH risks (e.g., safe and healthy workplaces, prevention of work-related injuries, etc.). This article extends the research and the results of a previous study of ours and comparatively presents (a) the main IMS standards concerning OSHMS and (b) the statistical results and new findings of an updated literature survey for additional time intervals (i.e., the years 1995–2005 and 2018–2020), ultimately covering the entire period of the years 1995–2020. Thus, the main targets of the study were (i) the implementation and comparative presentation of OSHMS standards, (ii) the reinforcement of their application at the worksites of any organization, and (iii) the development of a new ameliorated OSH management system model based on the knowledge from the literature review. On the other hand, some dominant results and findings are the following: (a) The industrial sector and construction sector demonstrate the highest percentage of OSHMS utilization. (b) The OHSAS 18001 standard remains the most frequent OSHMS standard even though, despite the fact that the ISO 45001:2018 is a recently developed OSHMS, it presents a considerable percentage distribution with reference to the total OSHMS articles despite its brief lifespan. (c) An effectual IMS OSHMS must merge various management systems, such as OSH (safety and health), QMS (quality), and EMS (environmental). (d) Organizations and businesses of any kind and any size can certainly develop and implement OSHMS standards. (e) Some substantial barriers to the implementation of an OSHMS standard are the high cost vis à vis implementation and management, the difficulty for the employees to realize its significance in OSH, and the complicatedness of combining different standards. (f) Occupational epidemiology must be one of the main features of an OSHMS standard. (g) Governments, employers, and employees admit day after day that the effectiveness of applying OSHMS standards at the organization level is considerable for decreasing the occupational hazards and risks and also for raising productivity

International Management System Standards Related to Occupational Safety and Health: An Updated Literature Survey

The implementation of an international management system (IMS) in any organization (or part thereof) creates an efficient framework regarding the sustainable development and the review of processes required to manage occupational safety and health (OSH) efficaciously. Moreover, Occupational Safety and Health Management System (OSHMS) standards identify requirements regarding OSH management systems, with the aim of enabling an organization to adopt dynamic policy and objectives that take into consideration lawful requirements relating to OSH risks (e.g., safe and healthy workplaces, prevention of work-related injuries, etc.). This article extends the research and the results of a previous study of ours and comparatively presents (a) the main IMS standards concerning OSHMS and (b) the statistical results and new findings of an updated literature survey for additional time intervals (i.e., the years 1995–2005 and 2018–2020), ultimately covering the entire period of the years 1995–2020. Thus, the main targets of the study were (i) the implementation and comparative presentation of OSHMS standards, (ii) the reinforcement of their application at the worksites of any organization, and (iii) the development of a new ameliorated OSH management system model based on the knowledge from the literature review. On the other hand, some dominant results and findings are the following: (a) The industrial sector and construction sector demonstrate the highest percentage of OSHMS utilization. (b) The OHSAS 18001 standard remains the most frequent OSHMS standard even though, despite the fact that the ISO 45001:2018 is a recently developed OSHMS, it presents a considerable percentage distribution with reference to the total OSHMS articles despite its brief lifespan. (c) An effectual IMS OSHMS must merge various management systems, such as OSH (safety and health), QMS (quality), and EMS (environmental). (d) Organizations and businesses of any kind and any size can certainly develop and implement OSHMS standards. (e) Some substantial barriers to the implementation of an OSHMS standard are the high cost vis à vis implementation and management, the difficulty for the employees to realize its significance in OSH, and the complicatedness of combining different standards. (f) Occupational epidemiology must be one of the main features of an OSHMS standard. (g) Governments, employers, and employees admit day after day that the effectiveness of applying OSHMS standards at the organization level is considerable for decreasing the occupational hazards and risks and also for raising productivity

International Occupational Health and Safety Management-Systems Standards as a Frame for the Sustainability: Mapping the Territory

A significant part of literature has shown that the adoption of Sustainability and Health-Safety management systems from organizations bears some substantial benefits since such systems (i) create a suitable frame for the sustainable development, implementation and review of the plans and/or processes, necessary to manage occupational health-safety (OHS) in their workplaces and (ii) imply innovative thinking and practices in fields of economics, policy-making, legislation, health and education. To this context, the paper targets at analysing current sustainability and OHSMSs in order to make these issues more comprehend, clear and functional for scholars and practitioners. Therefore, a literature survey has been conducted to map the territory by focusing on two interrelated tasks. The first one includes the presentation of the main International Management Systems (IMS) with focus on Sustainability and OHS (S_OHSMS) topics and the second task depicts a statistical analysis of the literature-review findings (for the years 2006–2017). In particular, the main purposes of the literature research were: (i) the description of key points of OHSMS and sustainability standards, (ii) the comparative analysis of their characteristics, taking into account several settled evaluation-criteria and (iii) the statistical analysis of the survey’s findings, while our study’s primary aim is the reinforcement of OHMSs’ application in any organization. The results evince, that the field of industry (with 28%) and also of the constructions (with 16%), concentrate the highest percentage of OHSMS use. In general, there were only few publications including OHSMSs (referred to various occupational fields) available in the scientific literature (during 2006–2017) but on the other hand, there was a gradually increasing scientific interest for these standards (especially during 2009–2012)

Risk Prioritization in a Natural Gas Compressor Station Construction Project Using the Analytical Hierarchy Process

Recently, the seamless construction and operation of natural gas pipelines has become even more critical, while the oil and gas industry’s capability to operate effectively with acceptable risks and hazardous situations is mainly dependent on safety. As a result, it is very important to have a wide knowledge of effective management tactics for enhancing implementation of safety regulations and procedures. The problem of assuring workers’ health and safety in the workplace is a crucial component in the endeavor to raise the productivity of labor and the level of competitiveness of building projects. To promote the health, safety, and well-being of workers, issues that are embedded within the concept of sustainability, we propose in this study a safety risk-assessment process that uses the analytical hierarchy process for assigning priorities to risks on construction worksites. This process uses a popular multicriteria method. The success of this strategy was shown by its application to the building of a natural gas compressor plant in Greece. The main contribution of this study is the application of a well-known multicriteria method for assessing risks in a natural gas compressor station construction project and prioritizing hazards to allocate budget for risk-mitigation measures

Safety Considerations by Synergy of HAZOP/DMRA with Safety Color Maps—Applications on: A Crude-Oil Processing Industry/a Gas Transportation System

A collaborative framework by the synergy of Hazard and Operability (HAZOP) process and the Decision-Matrix Risk Assessment (DMRA) in association with safety-color mapping (SCM) is presented, in order to identify critical points and prioritize risks, and also to visualize the occupational safety and health (OSH) situation, at the workplaces (i) of a sour crude-oil processing industry (SCOPI), and (ii) of a measurement and regulatory station (MRS) in a gas transportation system (GTS), situated in Greece. Firstly, the conventional HAZOP analysis is executed in order to identify the potential fault causes of abnormal conditions (deviations) in the plants. The application of the DMRA-modus is valuable to rank the identified risks (hierarchy of risks). In view of the results, both of the HAZOP pattern (for identifying the hazards) and also the DMRA one (for assessing and ranking the risks), SCMs have been derived for the specific workplaces of the SCOPI and the MRS/GTS station, which could be a precious means for safety managers to appraise the urgency of investing limited budgets in measures preventing particular types of deviations, and also protecting the employees