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Acquisitions, Overconfident Managers and Self-attribution Bias

John A. Doukas, Dimitris Petmezas
2007 European Financial Management  
Doukas and Kan (2004) show that diversifying acquirers experience greater excess cash flow declines and valuation discounts than non-diversifying acquirers.  ... 
doi:10.1111/j.1468-036x.2007.00371.x fatcat:s5o5nwt5wjbexa3qhy2ultfdsq

Efficient RES Penetration under Optimal Distributed Generation Placement Approach

Paschalis Gkaidatzis, Aggelos Bouhouras, Kallisthenis Sgouras, Dimitrios Doukas, Georgios Christoforidis, Dimitris Labridis
2019 Energies  
In this paper, a novel version of the Optimal Distributed Generation Placement (ODGP) problem regarding the siting and sizing of Renewable Energy Sources (RESs) units is presented, called Optimal RES placement (ORESP). Power losses constitute the objective function to be minimized, subject to operational constraints. The simultaneous installation of a mix of RESs is considered and the Capacity Factor (CF) ratio is used as an aid for taking into account: (a) the geographical characteristics of
more » ... e area, in which the examined Distribution Network (DN) is placed, (b) the different weather conditions, and (c) the availability of RESs, all of that at the same time, while keeping the problem complexity at minimum. The contribution of this work is that the proposed methodology bypasses the weather uncertainties and, thus, the RESs' power generation stochasticity and provides an adequate solution with minimum computational burden and time, since the proposed CF use allows solving the problem under a straightforward way. Unified Particle Swarm Optimization (uPSO) is used for solving ODGP and ORESP. Moreover, a sensitivity analysis regarding the CFs variations is performed and finally a comparison of the proposed method with a more realistic one is performed, to consolidate further the claims of this paper. The proposed method is evaluated on RES-region-modified 33- and 118 bus systems.
doi:10.3390/en12071250 fatcat:snxkj7bzuncrtkehxriezttam4

Battery energy storage systems modeling for online applications

George S. Misyris, Tomas Tengner, Antonis G. Marinopoulos, Dimitrios I. Doukas, Dimitris P. Labridis
2017 2017 IEEE Manchester PowerTech  
Over the last decade the use of battery energy storage systems (BESS) on different applications, such as smart grid and electric vehicles, has been increasing rapidly. Therefore, the development of an electrical model of a battery, capable to estimate the states and the parameters of a battery during lifetime is of critical importance. To increase the lifetime, safety and energy usage, appropriate algorithms are used to estimate, with the lowest estimation error, the state of charge of the
more » ... ry, the battery impedance, as well as its remaining capacity. This paper focuses on the development of model-based online condition monitoring algorithms for Li-ion battery cells, which can be extended to battery modules and systems. The condition monitoring algorithms were implemented after considering an optimal trade-off between their accuracy and overall complexity. Index Terms-Battery energy storage systems (BESS), capacity, equivalent circuit model (ECM), internal resistance, model-based method, parameter identification, state of charge (SOC), state of health (SOH).
doi:10.1109/ptc.2017.7980809 fatcat:o727cvwy55dxhntlvvtdm2lf2y

An Inference-based Knowledge Reuse Framework for Historical Product and Production Information Retrieval

Dimitris Mourtzis, Michael Doukas, Christos Giannoulis
2016 Procedia CIRP  
The reuse of past knowledge constitutes a key factor for improving manufacturing performance, during design, planning, and operational phases. However, valuable knowledge generated and associated to products and processes on a daily basis, remains implicit and its reusability is confined to a specific machine operator or within legacy IT databases. The work proposed in this paper introduces a framework to enable reusability of manufacturing knowledge through inference rules applied on
more » ... ing ontologies. Initially, a mechanism is used to access a Relational Database Management System (RDBMS) and through a rule-based approach, it exports the analogous ontological schema. The ontology constitutes the knowledge base and is stored in a knowledge repository. An inference engine is then used to query this repository and derive additional assertions, which are entailed from the base schema, on product, process, and resource. The method is developed in a web app, which offers to the users the capability to create, activate, and share rules and results on engineering topics. The effectiveness of the framework is validated using a real industrial case from a high-precision mould-making SME.
doi:10.1016/j.procir.2015.12.026 fatcat:soauqdkxp5czddhw6eom54n63q

Energy and GHG Emissions Aspects of the COVID Impact in Greece

Dimitri Lalas, Nikolaos Gakis, Sebastian Mirasgedis, Elena Georgopoulou, Yannis Sarafidis, Haris Doukas
2021 Energies  
The effects of COVID-19 have had devasting effects on both health and economies in 2020. At the same time, the lockdown and the downturn of economic activity resulted in a decrease in energy consumption and an accompanying reduction in greenhouse gas emissions. In this article, a comparison with the temperature adjustment of energy use is presented for the main carriers of electricity, natural gas, and oil products in the residential, tertiary, industry, and transport (road transport, domestic
more » ... viation, and navigation) sectors in 2020 against the previous two years in Greece, along with the corresponding emissions. As the comparison covers the entire year, both COVID peaks in the March–April and November–December periods and the corresponding lockdown effects as well as seasonal variations are included. The analysis shows a reduction, adjusted for temperature, of 3528 GWh in electricity and 10,286 GWh in transport, and an increase of 1916 GWh in heating and other final uses for a net 11,898 GWh decrease and a resulting emissions reduction of 3.48 MtCO2eq (1.29 MtCO2eq in electricity, 2.69 MtCO2eq in transport, and an increase of 0.54 MtCO2eq in heating), or 4.1%, from total national emissions in 2019. The effect is, to a considerable extent, the result of drastic tourist activity contraction, which is starkly evident in the electricity consumption in the Aegean islands. The comparison between the two lockdown periods brings out clear differences, with the reduction in the second one being considerably smaller as the population reverted, to a large extent, to pre-COVID behavior, which implies that no permanent gains from the COVID long-term impact toward decarbonization should be expected.
doi:10.3390/en14071955 fatcat:7keu5eg7mjeixjlvu3ikmffy7y

Hospitals' Cybersecurity Culture during the COVID-19 Crisis

Anna Georgiadou, Ariadni Michalitsi-Psarrou, Fotios Gioulekas, Evangelos Stamatiadis, Athanasios Tzikas, Konstantinos Gounaris, Georgios Doukas, Christos Ntanos, Luís Landeiro Ribeiro, Dimitris Askounis
2021 Healthcare  
The coronavirus pandemic led to an unprecedented crisis affecting all aspects of the concurrent reality. Its consequences vary from political and societal to technical and economic. These side effects provided fertile ground for a noticeable cyber-crime increase targeting critical infrastructures and, more specifically, the health sector; the domain suffering the most during the pandemic. This paper aims to assess the cybersecurity culture readiness of hospitals' workforce during the COVID-19
more » ... isis. Towards that end, a cybersecurity awareness webinar was held in December 2020 targeting Greek Healthcare Institutions. Concepts of cybersecurity policies, standards, best practices, and solutions were addressed. Its effectiveness was evaluated via a two-step procedure. Firstly, an anonymous questionnaire was distributed at the end of the webinar and voluntarily answered by attendees to assess the comprehension level of the presented cybersecurity aspects. Secondly, a post-evaluation phishing campaign was conducted approximately four months after the webinar, addressing non-medical employees. The main goal was to identify security awareness weaknesses and assist in drafting targeted assessment campaigns specifically tailored to the health domain needs. This paper analyses in detail the results of the aforementioned approaches while also outlining the lessons learned along with the future scientific routes deriving from this research.
doi:10.3390/healthcare9101335 pmid:34683015 fatcat:4w63ysmztfc6vhngrsgnoyyd6a

Simulation-Based Design of Production Networks for Manufacturing of Personalised Products [chapter]

Dimitris Mourtzis, Michalis Doukas, Foivos Psarommatis
2013 IFIP Advances in Information and Communication Technology  
This paper presents a method for the design of manufacturing networks focused on the production of personalised goods. The method, which is implemented to a software tool, comprises of a mechanism for the generation and evaluation of manufacturing network alternative configurations. An exhaustive search and an intelligent search algorithm are used, for the identification of efficient configurations. Multiple conflicting user-defined criteria are used in the evaluation, including cost, time, CO
more » ... emissions, energy consumption and quality. Discrete Event Simulation models of manufacturing networks are simulated for the calculation of performance indicators of flexibility, throughput and work-in-process, and are used for assessing the performance of centralised and decentralised networks. The results obtained through the exhaustive and intelligent search methods are compared. The applicability of the method is tested on a real-life industrial pilot case utilising data from an automotive manufacturer.
doi:10.1007/978-3-642-40352-1_38 fatcat:2roxlgjvqveubin2v64cl3j3ze

Performance Indicators for the Evaluation of Product-Service Systems Design: A Review [chapter]

Dimitris Mourtzis, Sophia Fotia, Michael Doukas
2015 IFIP Advances in Information and Communication Technology  
doi:10.1007/978-3-319-22759-7_68 fatcat:tazi5rlspjcrpfhiupsd5nv2pm

A toolbox for the design, planning and operation of manufacturing networks in a mass customisation environment

Dimitris Mourtzis, Michalis Doukas, Foivos Psarommatis
2015 Journal of manufacturing systems  
The task of design, planning and operation of manufacturing networks is becoming more and more challenging for companies, as globalisation, mass customisation and the turbulent economic landscape create demand volatility, uncertainties and high complexity. In this context, this paper investigates the performance of decentralised manufacturing networks through a set of methods developed into a software framework in a toolbox approach. The Tabu Search and Simulated Annealing metaheuristic methods
more » ... are used together with an Artificial Intelligence method, called Intelligent Search Algorithm. A multi-criteria decision making procedure is carried out for the evaluation of the quality of alternative manufacturing network configurations using multiple conflicting criteria including dynamic complexity, reliability, cost, time, quality and environmental footprint. A comparison of the performance of each method based on the quality of the solutions that it provided is carried out. The statistical design of experiments robust engineering technique is used for the calibration of the adjustable parameters of the methods. Moreover, the impact of demand fluctuation to the operational performance of the alternative networks, expressed thorough a dynamic complexity indicator, is investigated through simulation. The developed framework is validated through a real life case, with data coming from the CNC machine building industry.
doi:10.1016/j.jmsy.2014.06.004 fatcat:xzheiuor7rbvzeg4ob7qkmuhae

A Knowledge-Based Decision-Making Framework for the Design of Manufacturing Networks for Custom-Made Products [chapter]

Dimitris Mourtzis, Michalis Doukas
2014 IFIP Advances in Information and Communication Technology  
Efficient design of manufacturing networks is paramount for a sustainable growth. The establishment of mass customization and the transition to personalization complicates design activities and leads to vast amounts of unexploited data. This research work aims to exploit existing knowledge for enhancing decision-making during the initial manufacturing networks design, which carry out custom orders of industrial equipment. A method developed into software is proposed, comprising a Genetic
more » ... hm with knowledgeenriched operators and an intelligent initialization algorithm that exploits existing planning knowledge. The validation of the method is performed using data from a high-precision mold-making manufacturer and its network of first-tier suppliers.
doi:10.1007/978-3-662-44739-0_69 fatcat:ors7fxskurh4rieuf6gkuoz6xu

Atomic Physics at the 5 MV Tandem at Demokritos: the UoC APAPES project

I. Madesis, A. Dimitriou, S. Doukas, A. Laoutaris, C. Nounis, A. Lagoyannis, M. Axiotis, T. J. Mertzimekis, S. Harrisopulos, O. Sise, E. P. Benis, B. Sulik (+1 others)
2019 HNPS Proceedings  
University of Crete (UoC) has initiated the research initiative APAPES funded by THALES‡ that has already set up a new experimental station with a beam line dedicated solely on basic atomic physics research. This new experiment utilizing Zero-degree Auger Projectile Spectroscopy (ΖΑPS) is located at the 5 MV TANDEM accelerator of the National Center for Scientific Research (NCSR) "Demokritos" in Athens, and has been put together to perform high resolution studies of electrons emitted during
more » ... atom collisions. The apparatus consists of a Hemispherical Deflector Analyzer (HDA) combined with a 2-dimensional Position Sensitive Detector (PSD) and a doubly-differentially pumped gas cell containing the gas-target. The goal is to perform a systematic isoelectronic investigation of K-Auger spectra emitted from pre-excited and ground state He-like ions in collisions with gas targets using novel techniques. So far, various Auger electron spectra produced through collisions of mixed state (1s2, 1s2s3S) C4+ ion beam with various gas targets have been recorded. In addition, detailed simulations using SIMION have also explored the optimal lens voltages and the solid angle correction factors for long-lived metastable states. A terminal gas stripper system is scheduled to be installed in the accelerator, extending its range of available charge states and enabling the production of pure ground state as well as mixed state beams with different metastable fractions, a measurement vital to APAPES. Here, we report on the progress made up to date on the APAPES project, the description of the apparatus, updated results and plans for the near future.
doi:10.12681/hnps.1908 fatcat:jjrpxbdggve47gwshhz7uy4wm4

Adaption and validity of the "Physical Activity Class Satisfaction Questionnaire» (PACSQ) in Greek educational dancing context

Filippos Filippou, Stella Rokka, Stella Douka, Athena Pitsi, Aikaterini Koupani, Gregory Masadis, Dimitra Varsami, Eleni Samara, Dafni-Anastasia Filippou, Veroniki Karagiannidou, Dimitris Petanidis
2021 Cuadernos de Psicologia del Deporte  
La satisfacción es un factor que contribuye a aumentar la participación en las actividades deportivas, principalmente porque está vinculada a procedimientos conductuales responsables de generar sentimientos positivos en las personas involucradas. El objetivo de este estudio fue confirmar el "Cuestionario de Satisfacción de La Clase de Educación Física" en un contexto educativo de danza griega. También se examinó la coherencia interna del cuestionario. La muestra del estudio consistió en 482
more » ... icipantes, 184 de los cuales eran hombres y 298 eran mujeres. Todos los participantes asistieron a cursos de danza tradicional griega en diferentes asociaciones de danza en Grecia. La escala consta de 45 preguntas que constituyen nueve factores. Se realizaron los siguientes análisis estadísticos: La validez y fiabilidad del cuestionario se examinaron mediante un análisis de factores exploratorios y un análisis de factores confirmatorios. Se llevó a cabo un análisis de fiabilidad para examinar la cohesión interna de los factores. Se calcularon estadísticas descriptivas para examinar ampliamente el grado de satisfacción. El análisis de los resultados llegó a la siguiente conclusión: a) La versión griega del cuestionario mostró propiedades psicométricas estacionarias estables, que apoyan parcialmente su uso en el contexto de la danza griega. b) Las correlaciones entre las subescalas indicaban un modelo de factor relacionado que soporta la validez de la construcción de escalas. Satisfaction is a contributing factor to increasing participation in sports activities, especially due to the fact that it is linked to behavioral procedures responsible for causing positive feelings to people involved. The aim of this study was to confirm the "Physical Activity Class Satisfaction Questionnaire" in a Greek educational dancing context. The internal consistency of the questionnaire has also been examined. The sample of the study consisted of 482 participants, 184 males, and 298 females. All participants have attended Greek traditional dance courses in dancing associations among Greece. The scale consists of 45 questions which constitute nine factors. The following statistical analyses were carried out: Questionnaire's validity and reliability were examined via exploratory factor analysis and confirmatory factor analysis. Reliability analysis was conducted to examine the internal cohesion of the factors. Descriptive statistics have been calculated to broadly examine the degree of satisfaction. Results' analysis arrived at the following conclusion: a. The Greek version of the questionnaire has shown stable stationary psychometric properties, which partially support its use in the Greek dancing context. b. Correlations among subscales indicated a related factor model supporting the construct validity of the scale. A satisfação é um fator que contribui para aumentar a participação nas atividades desportivas, principalmentepor estar ligada a procedimentos comportamentais responsáveis por gerarem sentimentos positivos nas pessoas envolvidas. O objetivo deste estudo foi confirmar o "Questionário de Satisfação da Aula de Educação Física" num contexto educacional grego de dança. A consistência interna do questionário também foi examinada. A amostra do estudo foi composta por 482 participantes, sendo que 184 eram homens e 298 eram mulheres. Todos os participantes frequentaram cursos de dança tradicional grega em diferentes associações de dança na Grécia. A escala é composta por 45 questões que constituem nove fatores. Foram realizadas as seguintes análises estatísticas: A validade e confiabilidade do questionário foram examinadas através de uma análise de fatores exploratória e uma análise de fatores confirmatória. A análise de confiabilidade foi conduzida para examinar a coesão interna dos fatores. Foram calculadas estatísticas descritivas para examinaramplamente o grau de satisfação. A análise dos resultados chegou à seguinte conclusão: a) A versão grega do questionário mostrou propriedades psicométricas estacionárias estáveis, que suportam parcialmente o seu uso no contexto da dança grega. b) As correlações entre as subescalas indicaram um modelo de fator relacionado que suporta a validade de construção da escala.
doi:10.6018/cpd.421821 fatcat:xzh7zcx5kbay7buq7xumkvjyte

Determination of the solid angle and response function of a hemispherical spectrograph with injection lens for Auger electrons emitted from long lived projectile states

S. Doukas, I. Madesis, A. Dimitriou, A. Laoutaris, T. J. M. Zouros, E. P. Benis
2015 Review of Scientific Instruments  
Downloaded to IP: 043111-3 Doukas et al. Rev. Sci. Instrum. 86, 043111 (2015) Reuse of AIP content is subject to the terms at:  ...  Downloaded to IP: On: Tue, 14 Apr 2015 20:04:41 043111-4 Doukas et al. Rev. Sci. Instrum. 86, 043111 (2015) This article is copyrighted as indicated in the article.  ... 
doi:10.1063/1.4917274 pmid:25933845 fatcat:qrveyogut5fczobhfzhmyeki3m

High Resolution Auger Projectile Electron Spectroscopy of Li-like Ions Produced by Electron Capture in Collisions of He-like Ions with Gaseous Targets

A. Dimitriou, A. Laoutaris, I. Madesis, S. Doukas, E. P. Benis, B. Sulik, O. Sise, A. Lagoyannis, M. Axiotis, T. J.M. Zouros
2016 Journal of Atomic Molecular Condensate and Nano Physics  
Dimitriou et al.  ... 
doi:10.26713/jamcnp.v3i2.523 fatcat:vcgcsuijg5e2zbjzbq6whu6ojy

Hospital Resources May Be an Important Aspect of Mortality Rate among Critically Ill Patients with COVID-19: The Paradigm of Greece

Christina Routsi, Eleni Magira, Stelios Kokkoris, Ilias Siembos, Charikleia Vrettou, Dimitris Zervakis, Eleni Ischaki, Sotiris Malahias, Ioanna Sigala, Andreas Asimakos, Theodora Daidou, Panagiotis Kaltsas (+22 others)
2020 Journal of Clinical Medicine  
(Evangelia Douka), A.S. (Adamandia Sotiriou), V.M., P.T., A.K. (Apostolos Koroneos), P.P., Z.M., E.D. (Efrosini Dima), T.T., I.P., P.G., A.S. (Athina Strilakou), A.M., E.M. (Eleftheria Mizi), A.K.  ... 
doi:10.3390/jcm9113730 pmid:33233686 pmcid:PMC7699728 fatcat:gwfdwgsxdfau3m23a67ivu63oq
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