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A variable neighborhood search simheuristic algorithm for reliability optimization of smart grids under uncertainty
No full textA fundamental part of the self-healing grid is reducing disturbances and automatically responding to problems. Toward this goal, smart grid operators would be of great use to ensure stability after a potential overload for a planning horizon, as the electrical values are unknown. To evaluate the robustness of the topology reconfiguration after a disturbance, like an overload, reliability analysis through simulation can be employed. However, the simulation approach we propose in this paper, except for the excessive time it consumes, cannot assure the quality of its solutions. To achieve a more robust configuration, we, additionally, propose a single-stage stochastic program to optimize the grid topology configuration after a potential overload to ensure stability for the next day. We suggest a simheuristic approach based on a Variable Neighborhood Search metaheuristic to solve the above stochastic optimization problem. We evaluate the two approaches for this real-world problem, together with Creos Luxembourg S.A., the leading grid operator in Luxembourg. We show that our method can quickly suggest countermeasures to operators facing potential overloading incidents, ensuring the smart grid's stability for the next day.2942172220
Ambidextrous leadership: a narrative literature review for theory development and directions for future research
No full textPurposeThis study seeks to provide a narrative literature review of existing empirical research, in order to better understand the processes and theory of ambidextrous leadership, as well as its influence on followers, employees and organizations.Design/methodology/approachData from 26 studies were extracted and synthesied providing a critical discussion about the methodological and theoretical aspects of the studies identified in the review.FindingsIt was revealed the attributes for an effective ambidextrous leader, it was presented the recently proposed concept of ambidextrous leadership theory and it was noticed the main criticisms against the findings of the extant ambidextrous leadership literature. It was also identified many research gaps in the literature which in turn can guide academics in the development of ambidextrous leadership.Research limitations/implicationsThe ambidextrous leadership theory represents a novel and unique approach to the domain of leadership for creativity and innovation. It is shared across hierarchical levels throughout the organization. Leaders have a significant effect on employees' behaviors and should determine its applicability to different situations. Organizations require ambidextrous managers who combine flexible, situational and versatile leadership styles developing ever increasingly new and divergent ideas. Many research gaps in the literature were also identified that can guide academics in the development of ambidextrous leadership.Practical implicationsUnderstanding that ambidextrous leadership is required to significantly influence ambidexterity and innovation allows organizations to direct their leadership selection and development.Originality/valueThis review contributes to the ambidextrous leadership literature by creating a holistic picture of where it has been and where it should go.17220623
An optimization model for a manufacturing-inventory system with rework process based on failure severity under multiple constraints
No full textThe present work investigates a manufacturing-inventory system with a single machine and multiple products, featuring returns on sales and backorders. In the proposed model, some imperfect items, including scrapped and defective items, are produced by the manufacturer. Such items can be classified, based on the severity of the failure, into several categories; as a result, the rework process is carried out at different rates. Moreover, the implementation of the quality control policy requires monitoring and checking the items during the production and reworking processes via an inspection process. The present study is aimed to calculate and obtain the optimal values of the cycle length and backorders quantity for every product in order to achieve the minimum total cost of system considering machine capacity, service level, warehouse space, and budget constraints. To solve the presented model, given as a Nonlinear Programming (NLP) problem, the GAMS software as well as four commonly used algorithms, which are categorized among the meta-heuristic algorithms, is used. These algorithms include the GA (Genetic Algorithm), IWO (Invasive Weed Optimization), GWO (Grey Wolf Optimizer) and HHO (Harris Hawks Optimization) algorithms. Along with these algorithms, the Response Surface Methodology (RSM) is applied to calibrate the parameters of the proposed algorithms. Finally, several numeric problems are solved, the results of which are then compared with each other. Moreover, an analytical hierarchy process (AHP) technique for order performance by similarity to ideal solution (TOPSIS), which is a hybrid method of decision making with multiple attributes, is used for ranking the algorithms.3464221426
A comparative analysis of tools for developing location based games
No full textThe extended usage of mobile digital devices has nowadays become commonplace. Location-based games make the most of the mobile technologies by being played solely on mobile devices. The ever-growing interest for this type of applications goes beyond the mere goal of player entertainment, even reaching to the advocacy of civilization, research and education. In this article, three of the most famous and modern authoring tools for location-based games, Taleblazer, ARIS and Unity with Mapbox, are studied in-depth. The objective is to produce a comparative analysis of the aforementioned tools. Game developers may refer to this analysis to opt for the appropriate tool based on their needs, goals and technical expertise. In order to better understand the tool functionality and thus construct a reliable comparison framework, three game prototypes have been implemented. The results have shown that all studied tools provide the mechanics to develop location-based interactive experiences. Nevertheless, significant differences exist in their functionality, in their coding requirements, and in the extent of their respective learning curves. In conclusion, TaleBlazer seems to favor educational role-based games while ARIS favors hybrid story-based games. Unity with Mapbox, in turn, favors the development of recreational action-based games.3710040
A state-of-practice review of urban consolidation centres: practical insights and future challenges
No full textUrban Consolidation Centers (UCCs) constitute an appealing solution to urban freight distribution that ensures environmental-friendly and cost-efficient distribution in densely populated areas. Existing relevant research has placed the emphasis on the analysis of the underlying characteristics, services and operational advantages of UCCs, with limited focus on key determinants of long-term viability of UCC initiatives. The objective of this paper is to provide a comprehensive state-of-practice review of UCCs in Europe. The research capitalises on positive and negative experiences and practices so that it comes up with key success factors and viability drivers, common sources of failure, as well as key determinants for the successful operation and management of UCCs. A hybrid approach combining Systematic Literature Review (SLR) methodology with multiple case study research was adopted. Our analysis highlights specific strategic, tactical and operational factors that directly affect the successful operation and viability of a UCC.26673276
A superiority–inferiority hypothesis on disparagement humor: The role of disposition toward ridicule
No full textThe present paper adopts and substantiates a superiority–inferiority hypothesis on disparagement humor generation and appreciation. Two between-subjects (identification with a character acting as victimizer or victim) experiments address disparaging humorous advertising effectiveness, providing a novel perspective on very old questions. Perceived superiority and inferiority autonomously mediate the relationship between a disparaging advertisement and perceived humorousness. Individuals with high superiority motivation (i.e., high-katagelasticists) experience increased humorousness and an improved attitude toward the brand when they identify with a character acting as victimizer in the disparaging ad. People with a motivation to avoid inferiority (i.e., high-gelotophobes) experience reduced humorousness and lower positive attitudes toward the brand when they identify with a character who is victimized in the disparaging ad. Gelotophiles are not driven by feelings of superiority or inferiority and experience increased humorousness as well as more positive brand attitudes irrespective of the ad's victimization focus.204923941Special Issue: Contemporary Personality Perspectives in Consumer Behaviou
An Effective Multidimensional Model for Analyzing Social Web Big Data – Testing in simple Web 2.0 Applications of Internet Politics
No full textWeb 2.0 applications have provided researchers with vast quantities of Big Data, opening up new horizons for developing innovative analysis techniques that are applicable in multiple cognitive fields. Politics is definitely among them and is currently in a dynamically evolving range of these applications. Although modern Social Networking Platforms dominate the digital political landscape by supporting impressive volumes of political Big Data, political trends could nevertheless be traced in the pioneering network of one of the first participatory web applications: the blogs. The blogs and their social network, the so-called blogosphere, featured most of the advanced characteristics of contemporary Social Media Platforms, in a more simplistic form. After 15 years of digital existence, they maintained a noticeable presence in the Social Web while they have additionally undertaken the role of gateways to the multifaceted realm of Social Media Networks. Since their introduction, they have been providing digital citizens with a user-friendly tool to post political content, mutually interact, shape the political agenda and horizontally influence the public opinion as well as vertically affect the administrative decision centers. Therefore, they can be used as a reach Big Data fields suitable for testing multidimensional modeling methods towards mapping political trends, which could be upgraded accordingly for use in more complicated Social Media Applications. In this paper, a qualitative as well as quantitative method for analyzing the political blogosphere is introduced, consisting of three components. It focuses on the formation of blog communities, based on their hyperlink interconnectivity, the blogs’ influence and their users’ generated content. By applying a Multidimensional Scaling and Cluster Analysis, clusters were located, which correspond to the afore mentioned communities. These clusters, were found to be somehow related to the degree they may potentially influence their readers. Findings showed that high influence does not always involve high rates of hyperlinking. Eventually, by applying Content Analysis to the content of the blogs forming the clusters, the qualitative characteristics and the general topics of the political discussion were identified, regarding the specific survey period. Findings suggested that the qualitative characteristics of the political blogs are significantly related to the cluster they belong to, according to their hyperlinking. In the case study presented, the method proved to be able to investigate both the political qualitative and quantitative blogosphere characteristics. By applying it in the Greek political blogosphere, it proved to be able to thoroughly investigate the political debate that takes place on a portion of the social web, its characteristics and the influence it potentially has on public opinion.202158900
COVID-19 and organizational performance: a quasi-longitudinal and multilevel study of Greece
No full textBased on threat-rigidity theory, the purpose of this study is to examine the effect of organisational responses to COVID-19 on organisational performance, through the serially mediating mechanism of employee motivation and employee work engagement. The research analysis is based on two surveys referring to Greek organisations, which were conducted six months apart in 2020 and 2021. Using a quasi-longitudinal and multilevel structural equation modelling approach, the findings suggest that the first wave of the COVID-19 pandemic led to a decline in organisational performance due to fear and uncertainty which weakened employee motivation. The second wave of the COVID-19 pandemic revealed a trend of organisational performance returning to its initial equilibrium. Based on these findings, which underline the meaning of the serially mediating mechanism of employee motivation and employee work engagement, the study has several theoretical and practical implications.9411713
Digital Skills for Building and Using Personal Learning Environments
No full textIn the competitive worldwide reality, there is a need for lifelonglearning. People need to continuously learn new knowledge, acquirenew skills, and adapt to new situations. PLEs could supportthis continuous learning necessity. However, the learner shouldhave specific digital skills for PLE development and management.This paper addresses these needed digital skills. Initially, the paperintroduces a PLE model to present how the learner uses applicationsto access and manage resources in order to develop his/herPLE. Then, it describes the stages that the learner follows in orderto collect, manage, develop, and share resources as well as communicateand collaborate with others in his/her PLE. Finally, the paperpresents the digital skills needed by the learner in order to developand manage a PLE.Proceedings of 9th Technological Ecosystems for Enhancing Multiculturality (TEEM
Digital Transformation and Strategy in the Banking Sector: Evaluating the Acceptance Rate of E-Services
No full textDigital transformation in the banking sector is a continuous process that affects both the external and internal environment by redesigning internal processes and existing methods. There are many reasons that digital transformation takes place, such as servicing remote areas without physical branches, differentiation from competitors or reduction of operating costs. In any case, there are a lot of doubts about the acceptance of digital technologies. Thus, this article examines the acceptance rate of digital transformation in the banking sector in Greece. One hundred and sixty-one employees at Greek banks completed the survey. A Multivariate Regression Analysis was implemented to analyze the items of the Technology Acceptance Model. The findings of this paper indicate the perception of bank employees with regard to new technologies. This paper provides a practical contribution for executives of Greek banking organizations to schedule targeted educational programs to facilitate the transition to the new digital era for their employees. Executives are curious if employees are ready to accept and implement digitalization in their daily job routine. Therefore, the Technology Acceptance Model can provide answers to executives in facing these challenges.7320