62 research outputs found
Chief executive officer’s dark triad personality and firm's degree of internationalization: The mediating role of ambidexterity
No full textThis study empirically examines the relationships among CEOs’ dark triad personality (narcissism, psychopathy,
and Machiavellianism), ambidexterity, and firms’ internationalization behavior. Dark triad personality traits
have attracted growing attention in the fields of psychology and organizational behavior due to their influence
on individual decision-making, particularly by individuals in executive leadership roles. We extend research on
dark triad personality to international business (IB) and examine the link between IB decision-makers’ personality traits and firms’ IB outcomes. Our research highlights the complex dynamics shaping firm internationalization, with both the CEO’s dark triad personality and ambidexterity playing significant roles in driving firm
internationalization outcomes. An analysis of 405 firms from the United Kingdom and the United States reveals
that ambidexterity partially mediates the relationship between dark triad personality and the degree of internationalization and that firms pursuing internationalization may benefit from CEOs with a dark triad personality
Performance prediction of crosses in plant breeding through genotype by environment interactions
No full textPerformance prediction of potential crosses plays a significant role in plant breeding, which aims to produce new crop varieties that have higher yields, require fewer resources, and are more adaptable to the changing environments. In the 2020 Syngenta crop challenge, Syngenta challenged participants to predict the yield performance of a list of potential breeding crosses of inbreds and testers based on their historical yield data in different environments. They released a dataset that contained the observed yields for 294,128 corn hybrids through the crossing of 593 unique inbreds and 496 unique testers across multiple environments between 2016 and 2018. To address this challenge, we designed a new predictive approach that integrates random forest and an optimization model for G × E interaction detection. Our computational experiment found that our approach achieved a relative root-mean-square-error (RMSE) of 0.0869 for the validation data, outperforming other state-of-the-art models such as factorization machine and extreme gradient boosting tree. Our model was also able to detect genotype by environment interactions that are potentially biologically insightful. This model won the first place in the 2020 Syngenta crop challenge in analytics.This article is published as Ansarifar, Javad, Faezeh Akhavizadegan, and Lizhi Wang. "Performance prediction of crosses in plant breeding through genotype by environment interactions." Scientific Reports 10, no. 1 (2020): 11533.
DOI: 10.1038/s41598-020-68343-1.
Copyright 2020 The Author(s).
Attribution 4.0 International (CC BY 4.0).
Posted with permission
It’s all about resources: Narcissistic CEOs and entrepreneurial orientation during disruptions
No full textResearch regarding the influence of personality traits, such as narcissism, on entrepreneurial orientation (EO) is burgeoning, yet the role of affective and cognitive mechanisms is under-examined. Drawing from research on conservation of resources (COR) theory, entrepreneurial cognition and emotion, we examine the narcissism-EO relationship nexus. Specifically, we analyse the mediating role of the resource-induced coping heuristic (RICH) and the moderating influence of fear on the relationship between narcissism and EO. Longitudinal data from CEO-entrepreneurs of SMEs in six countries were collected during the COVID-19 disruptions. Results suggest that the RICH fully mediates the relationship between narcissism and EO. Fear of COVID-19 (FC-19) positively influenced EO and strengthened the narcissism-RICH relationship. Further, pandemic-related disruptions negatively influenced EO and attenuated the positive influence of FC-19 on EO. These findings offer insight into the drivers of entrepreneurial behaviour during times of disruption
Kernel-Summability Methods and the Silverman-Toeplitz Theorem
No full textWe introduce kernel-summability methods in Banach spaces using the
vector-valued integrals and prove an analogue of the Silverman-Toeplitz Theorem
for regular kernel-summability methods. We also show that if is a Banach
space and one kernel-summability method is included in another
kernel-summability method for scalar-valued functions, then the first method is
included in the second method, for -valued functions. This extends a
previous result from Javad Mashreghi, Thomas Ransford and the author. We then
apply these abstract results to the summability of Taylor series of functions
in a Banach space of holomorphic functions on the unit disk
Prediction of clear water local scour at bridge piers
No full textLAUREA MAGISTRALELa funzionalità delle infrastrutture è cruciale per la società moderna e ogni fallanza delle stesse provoca conseguenze negative per l’economia e il benessere dei cittadini. I ponti fluviali non fanno eccezione, dal momento che eventuali danneggiamenti o crolli di queste strutture possono provocare ingenti danni, isolamento di territori e perdite di vite umane. La vulnerabilità dei ponti dipende da diversi fenomeni, tra i quali si possono includere i processi erosivi localizzati.
A dispetto della grande mole di ricerche condotte su questi fenomeni, non sono ancora disponibili equazioni per la previsione dell’evoluzione temporale dell’erosione, che possano ritenersi di validità generale. Molto spesso la validità delle formule disponibili è limitata agli esperimenti condotti per ottenerle.
In questo lavoro è stato analizzato un ampio campione di dati di letteratura, per il caso dell’erosione a una pila circolare in condizioni di acque chiare. È stata stimata una nuova equazione con l’obiettivo di rappresentare il complesso dei dati.
I dati proposti dai singoli autori non sono in generale omogenei, perché ottenuti tramite procedure sperimentali diverse e inquadrati in schemi di riferimento diversi. È stato dunque necessario un lavoro di omogeneizzazione dei parametri. Uno di quelli più importanti è la velocità del flusso, che alcuni autori considerano media sulla sezione trasversale e altri sulla profondità. I valori di velocità sono stati convertiti laddove necessario. Un opportuno inquadramento adimensionale è stato usato per individuare i parametri di maggiore importanza: la snellezza della pila in relazione alla profondità della corrente, la dimensione dell’ostacolo rispetto a quella dei sedimenti, l’intensità del flusso rispetto alle condizioni critiche, e il tempo. La formula finale proposta è costituita da una produttoria di funzioni dei singoli parametri.
La capacità della formula di prevedere i valori di erosione è stata confrontata con quella di analoghi strumenti disponibili in letteratura, riscontrando un generale miglioramento.
Parole chiave: Pila di ponte; Erosione localizzata; Evoluzione temporale; Stima dell’erosione.In modern societies, the normal life of people is highly dependent on the operation of the infrastructures. Any disruption to the normal performance of these critical infrastructures can have negative impacts on the economy of the society and the welfare of the citizens.
Bridges at river crossings, being one of the most important and vital infrastructures, are prone to a major damage during floods. Damage can be caused by various reasons; one of the main ones is riverbed scour at bridge foundations. The damage can range from minor erosion to complete failure of the bridge structure which can lead to death casualties and isolation of entire areas.
In spite of the extensive research efforts on this topic, a general equation which can be able to predict the temporal evolution of scour depth is still missing due to the fact that the existing formulae are manly appropriate for the experiments that they are developed for.
In this work, an extensive data set for long-duration, clear-water pier scour experiments has been considered. Data from several authors were used to fit a novel predictive equation for the temporal development of the maximum scour depth at a circular pier.
Since the mentioned data by different authors were included in different frameworks, it was necessary to make them homogeneous and present them with the same parameters. In this respect, the approach flow velocity was one of the most influential parameters for the scour trend; some authors used a cross-sectional average flow velocity, some others used instead a depth-averaged value at mid-channel. Therefore, values were converted whenever necessary. A dimensionless framework was considered to highlight the most relevant parameters; the final predictive equation was the product of functions of the individual parameters. The most important dimensionless parameters were the flow shallowness, the sediment coarseness, the ratio of the flow velocity to the critical one, and the dimensionless time.
The performance of the estimated scour function was finally compared to that of previous literature equations, documenting a general improvement of prediction capabilities.
Author keywords: Bridge piers; Local scour; Temporal evolution; Scour prediction
High power quality maximum power point tracking-based islanding detection method for grid-connected photovoltaic systems
No full textIslanding is a condition when distributed generators (DGs) are disconnected electrically from the upstream network. This unwanted situation should be detected effectively to ensure the safety of the maintenance staffs and power quality (PQ) requirements. This paper presents a new high PQ maximum power point tracking (MPPT)-based methodology for detecting the islanding operating mode of grid-connected photovoltaic systems (GCPVSs). In the recommended two-level scheme, a disturbance is injected into the MPPT algorithm under suspicious conditions, recognized by a passive criterion. This disturbance declines the DG active power output remarkably, drifting the output voltage beyond the minimum standard set in islanding state while its impact is negligible at the network presence. The effectiveness of the proposed technique has been evaluated through several hardware-in-the-loop simulations for a case study system, containing two power plant GCPVSs equipped with a pair of multi-functional relays. The results highlight precise islanding classification within 137 ms with the small non-detection zone. Moreover, the results of PQ analyses indicate acceptable total demand distortion and harmonic spectra of the output current in compliance with the existing standards under various DG power penetrations. Since the presented scheme diminishes the active power output in case of suspicious islanding events, its influence on GCPVS efficiency has been studied as well. The outputs underline that the efficiency drops by 0.52% whilst the disturbance is stimulated every minute of the time. It is finally concluded that the proposed technique provides a reliable islanding classification as well as insignificant degradation of PQ and efficiency.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Intelligent Electrical Power Grid
Comprehensive Study on Transformer Fault Detection via Frequency Response Analysis
No full textThe sudden outage of a transformer due to a fault can cause irreparable damage to the electricity industry. Hence, by conducting momentarily inspections of the transformer’s condition, faults can be promptly detected, and the transformer can be disconnected from the power grid to prevent subsequent failures in this equipment. Detecting faults at an early stage can also result in reduced repair costs. One recent promising technique for fault detection is Frequency Response Analysis (FRA), which compares the transformer’s response in healthy and faulty conditions for understanding the occurrence of transformer faults. This paper presents a comprehensive and accurate modeling approach for the behavior of the transformer at different frequencies, followed by an exposition of the requirements for implementing this method in order to find the fault type, severity, and location. Additionally, various methods for analyzing the results of frequency response are introduced and discussed. In this regard, attempts have been made to introduce advanced complementary methods to address the weaknesses and limitations of the frequency response method. Finally, the concepts are summarized, and suggestions for further research with applications in this field are presented and compared
The Literature Landscape of Covid-19 and Socio-Economic Research: A Bibliometric Analysis
No full textThis study reviews the literature on COVID-19 and socio-economic studies to
identify current research areas and suggest ways forward through bibliometric analysis
of 426 published documents retrieved from the Scopus database concerning COVID-19,
scientific and socio-economic research in the year 2020. The findings reveal that the
pandemic affected the socio-economic domain through the imposed social distancing,
applied based on different severity levels in various countries. This study shows that the
most common keyword used in titles, abstracts and author keywords is “COVID-19”. Twoauthored documents have the highest number of total publications. The top affiliations are
the University College London and the London School of Hygiene and Tropical Medicine.
The United States is the top country in terms of total publications. The findings highlighted
the increase in stress levels in the healthcare system during the COVID-19 pandemic and
the necessity of scientific research to help scholars understand the various socio-economic
impacts of this crisis. The most influential aspects of research are virus and protein
interaction maps and the effects of the pandemic on economics and psychology. The main
search stream is COVID-19 and its effects on health. This study has practical implications
for policymakers and governments in implementing social policies to reduce anxiety in
social situations among households and protect public health
Review on islanding detection methods for grid-connected photovoltaic systems, existing limitations and future insights
No full textThe connection of renewable energy sources (RESs) to the distribution network has been rising at a steady pace over the past decades. The great penetration of RESs such as grid-connected photovoltaic system brings new technical challenges to the distribution networks such as unintentional islanding. Conceptually, this situation occurs when a portion of the network that has been isolated from the main grid remains energised by the embedded RESs. This unexpected scenario should be thereby identified effectively to avoid frequency and voltage deviations and their hazardous effects. The aim of this paper is to provide a comprehensive review on the recently developed islanding detection methods for grid-following/grid-connected photovoltaic system, analyse their existing limitations, and suggest possible future research implementations. In this context, an in-depth comparison is provided considering the main features used in islanding detection methods such as non-detection zone, detection time, implementation cost and complexity, and power quality degradation. Finally, the main technical requirements established by the current grid codes are recalled identifying potential multi-functional approaches to expand the current islanding detection capabilities.Intelligent Electrical Power Grid
Plot and Personification in “Tehran-e- Makhuf“
No full textStory is one of the important and influential literary genres that deserves to research on its structure and content .By study and analysis of a story, the reader could comprehend the textual messages and change his attitude toward life and different issues .After defining of the social novel, the author tries to analyze plot and personification in novel of “Tehran-e- Makhuf” and respond to the questions on the method employed for plot and personification and analyze it from plot and its components such as conflict, suspension and resolution and compare the differences and similarities between old tales and modern novels.The plot of “Tehran-e- Makhuf” is not so complex due to its subject and content and natural order of events dominates on artificial discipline and it lacks open plot. Of main elements of plot, conflict is more outstanding here. This novel is full of emotional and moral conflicts and there is no similarity with historical novels that describe good and bad conflicts. Cause and effect relationship is main element of plot that shadows on the story events .In “Tehrna-e- Makhuf”, the author tries to violate the principles and cause to imbalance in natural events sequences with discomposing rational and experiential relationship and take action toward artificiality and unnatural suspension. In creating suspension by emphasis on incidences in some extremist cases, Kazemi tries to found the story based on the considerable sequence of events and this conduct reduces quality of the story significantly and leads to imbalance in rational and acceptable discipline.Kazemi employs direct or reporting personification mostly. This novel lacks diversity in personage considerably .All characters speak in similar style and there is no particular speech style. The personification of Kazemi in “Tehran-e-Makhuf” is continuous and interdependent in style of old tales and novel in European account. In some cases, he approaches to story characters specifications and in other cases, he distances from traditional personification due to familiarity with western countries particularly Russian and French writers .Indeed, it can be said that personification in “Tehran-e- Makhuf” is passing from traditional to modern and western style. The characters of “Tehran-e- Makhuf” are classified in two categories: the first category involves aristocrats and their purpose is power and wealth and prevention of any social shift. They are identified by traits like “reveler”, “hypocrite”, “stingy” and “rich” .The characters like Siyavash Mirza, F.Saltaneh, Shazdeh and Ali Ashraf khan are in this group .The second category is identified by traits like “noble”, “loyal”, “sufferer “ and “patient” and they are common people. Characters like Farrokh, Javad, servant of Farrokh, Mahin and Efat are in this group and they are noble and humanely and good .The main and secondary personages are constant and static in this novel .They attend in the story without changing. All characters introduced by Kazemi in “Tehran-e- Makhuf” are real and they reflect society realities .The characters reflect historical and social realities of particular place and time
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