Xiaoqian Sun, Changhong Zheng, Sebastian Wandelt and Anming Zhang
The COVID-19 pandemic, having emerged early in the year 2020, had a devastating impact on the whole aviation industry. Airlines were particularly hit hard, given unprecedented…
Abstract
The COVID-19 pandemic, having emerged early in the year 2020, had a devastating impact on the whole aviation industry. Airlines were particularly hit hard, given unprecedented border closures, the inability to adapt to highly volatile demand, and an embarrassing lack of overall pandemic preparedness. As of summer 2022, the airline industry seems on the track of strong recovery, with many airlines returning to profits and passenger numbers occasionally exceeding those of pre-COVID-19 levels. This study investigates the induced pandemic cycle, from January 2020 to December 2022, through tools from the network science literature. We model airline networks as a collection of nodes, representing airports, and a collection of links, representing direct flights between airports. This analysis has a strong focus on spatiotemporal evolution of airlines worldwide during the COVID-19 pandemic, leading to a comprehensive description of network science effects and counter measures during this excessive health and economic shock. Such an analysis could be helpful for better dealing with future pandemics, which are likely to emerge, if potential lessons learned are not implemented by the aviation industry.
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The purpose of this paper is to present a new approach in the concept and implementation of autonomous micro‐spacecraft. The one true “artificial agent” approach to autonomy…
Abstract
The purpose of this paper is to present a new approach in the concept and implementation of autonomous micro‐spacecraft. The one true “artificial agent” approach to autonomy requires the micro‐spacecraft to interact in a direct manner with the environment through the use of sensors and actuators. As such, little computational effort is required to implement such an approach, which is clearly of great benefit for limited micro‐satellites. Rather than using complex world models, which have to be updated, the agent is allowed to exploit the dynamics of its environment for cues as to appropriate actions to achieve mission goals. The particular artificial agent implementation used here has been borrowed from studies of biological systems, where it has been used successfully to provide models of motivation and opportunistic behaviour. The so‐called “cue‐deficit” action selection algorithm considers the micro‐spacecraft to be a non‐linear dynamical system with a number of observable states. Using optimal control theory rules are derived which determine which of a finite repertoire of behaviours the satellite should select and perform. The principal benefits of this approach is that the micro‐spacecraft is endowed with self‐sufficiency, defined here to be the ability to achieve mission goals, while never placing itself in an irrecoverable position.
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Kenneth Leithwood, Jingping Sun, Randall Schumacker and Cheng Hua
This study extends research on one of the most frequently cited school leadership frameworks by examining the psychometric properties of the instrument designed to assess many of…
Abstract
Purpose
This study extends research on one of the most frequently cited school leadership frameworks by examining the psychometric properties of the instrument designed to assess many of the practices included in that framework.
Design/methodology/approach
Using data collected from 1,401 teachers the study examined the instrument’s measurement invariance, score reliabilities, as well as construct and predictive validities. Polytomous latent trait models (Many-Facet Rasch model), scale and principal component analysis using second-order Confirmatory Factor Analysis, and Structural Equation Modeling (SEM)-Path modelling were used for these purposes.
Findings
Findings report levels of score reliability and valid score inferences. Results concerning the predictive validity of the instrument indicate a complex set of relations among the domains of leadership practices measured by the instrument, variables selected as mediators of leaders’ influence, and their direct and indirect effects on student learning.
Research limitations/implications
This study provides researchers with a reliable and valid instrument for use in their future research. Data for the study were provided by elementary teachers in one US state. The extent to which results of the instrument are valid across different cultural and organizational settings remains to be determined.
Practical implications
Leadership developers may find the instrument useful for assessing the strengths and weaknesses of those participating in their programs while leaders themselves many find the instrument useful for self-diagnosis.
Originality/value
This study contributes to the development of school leadership measures by including Rasch modeling among the methods used for examining the instrument’s psychometric properties.
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Kathleen Rehbein, Frank den Hond and Frank G. A. Bakker
Corporate social responsibility (CSR) and corporate political activity (CPA) are two important components of firms’ nonmarket strategies, oriented toward shaping the firm’s…
Abstract
Corporate social responsibility (CSR) and corporate political activity (CPA) are two important components of firms’ nonmarket strategies, oriented toward shaping the firm’s political and social conditions. Although this is acknowledged in the literature, there are contradictory arguments and evidence, concerning, first, whether and under which conditions firms align their CPA and CSR activities, and second, what the impacts might be if they do align these activities. In light of this, this chapter draws from earlier reviews of nonmarket strategies, to explore the factors at multiple levels, macro and micro, that may drive a firm’s alignment of CPA and CSR. In doing so, we draw from management research to identify the macro- and micro-level factors that shape CPA and CSR alignment as CSR and CPA alignment research mostly focuses on outcomes rather than identifying the drivers of alignment. We develop a general model that integrates the macro- and micro-level discussions to make suggestions about where future research needs to go to increase understanding of when corporations will combine their CPA and CSR efforts and the merits of these efforts.
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Xiangru Wu, Kun Wang and Xiaowen Fu
This chapter reviews the competition between full-service carrier (FSC) and low-cost carrier (LCC) in China. More importantly, we discuss the impacts of the COVID-19 pandemic on…
Abstract
This chapter reviews the competition between full-service carrier (FSC) and low-cost carrier (LCC) in China. More importantly, we discuss the impacts of the COVID-19 pandemic on FSC–LCC competition. Specifically, the airlines' route choices and also the market contact between FSCs and LCCs in China are examined and discussed. Our review results suggest that, despite the rapid growth of the independent LCC Spring Airlines and the establishment of new subsidiary LCCs by FSCs, China's LCC sector still plays relatively minor roles compared with many fully deregulated markets. Subsidiary LCCs serve more as competitive tools for their parent FSCs, primarily deployed on their parent FSCs' routes to jointly compete against rival FSCs. This competition is primarily focused on niche regional markets rather than engaging in full-scale competition. Spring Airlines also strategically avoided direct head-to-head competition with FSCs before the pandemic by mainly connecting with the secondary cities. However, the pandemic has introduced significant changes, notably the network differentiation between FSCs and LCCs in mainland China. With the relaxation of government's regulations on airline route entries into hub airports during pandemic, Chinese LCCs have shifted their focus toward serving more dense routes, especially those connected to the top five cities. This shift has led to an intensified head-to-head competition between LCCs and FSCs following the outbreak of the pandemic. Such a process is likely to continue in the years to come. This chapter's discussions could also provide new insights into LCC development and the impact of the pandemic on FSC–LCC competition interactions to supplement existing literature studying other major airline markets.
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The most powerful and effective forces of hierarchizing are those that naturalize difference so that it is beyond dispute and something to be tacitly accepted. In the Classic Maya…
Abstract
The most powerful and effective forces of hierarchizing are those that naturalize difference so that it is beyond dispute and something to be tacitly accepted. In the Classic Maya world, this “social speciation” was materialized and naturalized through a complex web of ritual practice, deity emulation, enhancement of body aesthetics, and the fabrication and possession of hypertrophic goods. The architecture of Classic Maya royal courts broke with an older Maya residential pattern of accretional construction filled with ancestral burials in order to materialize more effectively social difference, to provide space for exclusive ritual performance, and to showcase the highly valued and gendered labor of textile production. Such instruments of authority are “weapons of exclusion” that can be wielded to fend off assaults on hierarchy. From this perspective, informed by the ritual economy approach, the profound transformations of the 9th century in the Maya lowlands are considered an assault that was not defendable.
Monojit Das, V.N.A. Naikan and Subhash Chandra Panja
The aim of this paper is to review the literature on the prediction of cutting tool life. Tool life is typically estimated by predicting the time to reach the threshold flank wear…
Abstract
Purpose
The aim of this paper is to review the literature on the prediction of cutting tool life. Tool life is typically estimated by predicting the time to reach the threshold flank wear width. The cutting tool is a crucial component in any machining process, and its failure affects the manufacturing process adversely. The prediction of cutting tool life by considering several factors that affect tool life is crucial to managing quality, cost, availability and waste in machining processes.
Design/methodology/approach
This study has undertaken the critical analysis and summarisation of various techniques used in the literature for predicting the life or remaining useful life (RUL) of the cutting tool through monitoring the tool wear, primarily flank wear. The experimental setups that comprise diversified machining processes, including turning, milling, drilling, boring and slotting, are covered in this review.
Findings
Cutting tool life is a stochastic variable. Tool failure depends on various factors, including the type and material of the cutting tool, work material, cutting conditions and machine tool. Thus, the life of the cutting tool for a particular experimental setup must be modelled by considering the cutting parameters.
Originality/value
This submission discusses tool life prediction comprehensively, from monitoring tool wear, primarily flank wear, to modelling tool life, and this type of comprehensive review on cutting tool life prediction has not been reported in the literature till now. The future suggestions provided in this review are expected to provide avenues to solve the unexplored challenges in this field.