The purpose of this study is to further advance the multiple space/time subdomain framework with model reduction. Existing linear multistep (LMS) methods that are second-order…
Abstract
Purpose
The purpose of this study is to further advance the multiple space/time subdomain framework with model reduction. Existing linear multistep (LMS) methods that are second-order time accurate, and useful for practical applications, have a significant limitation. They do not account for separable controllable numerical dissipation of the primary variables. Furthermore, they have little or no significant choices of altogether different algorithms that can be integrated in a single analysis to mitigate numerical oscillations that may occur. In lieu of such limitations, under the generalized single-step single-solve (GS4) umbrella, several of the deficiencies are circumvented.
Design/methodology/approach
The GS4 framework encompasses a wide variety of LMS schemes that are all second-order time accurate and offers controllable numerical dissipation. Unlike existing state-of-art, the present framework permits implicit–implicit and implicit–explicit coupling of algorithms via differential algebraic equations (DAE). As further advancement, this study embeds proper orthogonal decomposition (POD) to further reduce model sizes. This study also uses an iterative convergence check in acquiring sufficient snapshot data to adequately capture the physics to prescribed accuracy requirements. Simple linear/nonlinear transient numerical examples are presented to provide proof of concept.
Findings
The present DAE-GS4-POD framework has the flexibility of using different spatial methods and different time integration algorithms in altogether different subdomains in conjunction with the POD to advance and improve the computational efficiency.
Originality/value
The novelty of this paper is the addition of reduced order modeling features, how it applies to the previous DAE-GS4 framework and the improvement of the computational efficiency. The proposed framework/tool kit provides all the needed flexibility, robustness and adaptability for engineering computations.
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The purpose of this paper is to describe a novel implementation of a multispatial method, multitime-scheme subdomain differential algebraic equation (DAE) framework allowing a mix…
Abstract
Purpose
The purpose of this paper is to describe a novel implementation of a multispatial method, multitime-scheme subdomain differential algebraic equation (DAE) framework allowing a mix of different space discretization methods and different time schemes by a robust generalized single step single solve (GS4) family of linear multistep (LMS) algorithms on a single body analysis for the first-order nonlinear transient systems.
Design/methodology/approach
This proposed method allows the coupling of different numerical methods, such as the finite element method and particle methods, and different implicit and/or explicit algorithms in each subdomain into a single analysis with the GS4 framework. The DAE, which constrains both space and time in multi-subdomain analysis, combined with the GS4 framework ensures the second-order time accuracy in all primary variables and Lagrange multiplier. With the appropriate GS4 parameters, the algorithmic temperature rate variable shift can be matched for all time steps using the DAE. The proposed method is used to solve various combinations of spatial methods and time schemes between subdomains in a single analysis of nonlinear first-order system problems.
Findings
The proposed method is capable of coupling different spatial methods for multiple subdomains and different implicit/explicit time integration schemes in the GS4 framework while sustaining second-order time accuracy.
Originality/value
Traditional approaches do not permit such robust and flexible coupling features. The proposed framework encompasses most of the LMS methods that are second-order time accurate and unconditionally stable.
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Masao Shimada, David Tae, Tao Xue, Rohit Deokar and K K Tamma
The purpose of this paper is to present new implementation aspects of unified explicit time integration algorithms, called the explicit GS4-II family of algorithms, of a…
Abstract
Purpose
The purpose of this paper is to present new implementation aspects of unified explicit time integration algorithms, called the explicit GS4-II family of algorithms, of a second-order time accuracy in all the unknowns (e.g. positions, velocities, and accelerations) with particular attention to the moving-particle simulation (MPS) method for solving the incompressible fluids with free surfaces.
Design/methodology/approach
In the present paper, the explicit GS4-II family of algorithms is implemented in the MPS method in the following two different approaches: a direct explicit formulation with the use of the weak incompressibility equation involving the (modified) speed of sound; and a predictor-corrector explicit formulation. The first approach basically follows the concept of the explicit MPS method, presented in the literature, and the latter approach employs a similar concept used in, for example, a fractional-step method in computational fluid dynamics.
Findings
Illustrative numerical examples demonstrate that any scheme within the proposed algorithmic framework captures the physics with the necessary second-order time accuracy and stability.
Originality/value
The new algorithmic framework extended with the GS4-II family encompasses a multitude of pastand new schemes and offers a general purpose and unified implementation.
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Asli Ogunc and Randall C. Campbell
Advances in Econometrics is a series of research volumes first published in 1982 by JAI Press. The authors present an update to the history of the Advances in Econometrics series…
Abstract
Advances in Econometrics is a series of research volumes first published in 1982 by JAI Press. The authors present an update to the history of the Advances in Econometrics series. The initial history, published in 2012 for the 30th Anniversary Volume, describes key events in the history of the series and provides information about key authors and contributors to Advances in Econometrics. The authors update the original history and discuss significant changes that have occurred since 2012. These changes include the addition of five new Senior Co-Editors, seven new AIE Fellows, an expansion of the AIE conferences throughout the United States and abroad, and the increase in the number of citations for the series from 7,473 in 2012 to over 25,000 by 2022.
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Tae-Yeol Kim, Brad Gilbreath, Emily M. David and Sang-Pyo Kim
The purpose of this paper is to test whether self-verification striving serves as an individual difference antecedent of emotional labor and explore whether various emotional…
Abstract
Purpose
The purpose of this paper is to test whether self-verification striving serves as an individual difference antecedent of emotional labor and explore whether various emotional labor tactics acted as mediating mechanisms through which self-verification striving relates to employee outcomes.
Design/methodology/approach
The sample used in this paper consisted of supervisor–subordinate dyads working in six hotels in South Korea and used multi-level analyses and the Monte Carlo method to test the research hypotheses presented in this paper.
Findings
Self-verification striving was positively and directly related to job performance as well as two out of three forms of emotional labor (i.e. the expression of naturally felt emotions and deep acting). Self-verification striving also indirectly related to job satisfaction through the expression of naturally felt emotions and indirectly related to job performance through deep acting.
Practical implications
The findings of this paper suggest that organizations should consider self-verification striving as an employment selection criterion and provide training programs to help their customer service employees engage in appropriate types of emotional labor.
Originality/value
This paper is the first to explore the underlying mechanisms through which self-verification striving relates to employee outcomes. It also empirically bolsters the notion that expressing naturally felt emotions is an important means of authentic self-expression that positively contributes to job satisfaction. Further, the authors found that self-verification striving positively relates to job performance partially through deep acting. Moreover, they have shown that self-verification striving, as an individual differences variable, is an antecedent of different types of emotional labor.
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This paper uses various Data Envelopment Analysis (SBM-DEA) approaches to study the efficiency of major airlines in Asia-Pacific region. To evaluate the operation efficiency of…
Abstract
This paper uses various Data Envelopment Analysis (SBM-DEA) approaches to study the efficiency of major airlines in Asia-Pacific region. To evaluate the operation efficiency of fourteen major airlines in Asia-Pacific region from 2003-2011, Available Seat Kilometers(ASK), Available Ton Kilometers(ATK), the number of employees are used as input factors, Revenue Passenger Kilometers(RPK), Revenue Ton Kilometers(RTK), the amount of Sales are used as output factors.
The non-radial SBM-DEA (Slacks-based Measure of Efficiency) model was able to provide a more comprehensive efficiency of combining economic performance and regional difference. And it was also able to capture slack values in input excess and output shortage.
The results demonstrate that Korea and Japan airlines are operated efficiently and could be regarded as the benchmarking airlines. On the other hand, most of the China and ASEAN airlines are deemed to be inefficient. Also analyzing slacks may be more suitable way for the evaluation or suggestion of an improvement scheme for the inefficient airlines. The excess of labor is the major cause of the airlines’ inefficiency.
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Hardly surprisingly, like many fellow Glaswegians, I grew up believing that the language of the majority of my fellow citizens was slang1 and hence to be disparaged, if not…
Abstract
Hardly surprisingly, like many fellow Glaswegians, I grew up believing that the language of the majority of my fellow citizens was slang1 and hence to be disparaged, if not altogether despised. The fact that we were all equally able to express ourselves in Glaswegian or varying degrees of “Standard” English was conveniently overlooked. The hegemonical dominance of the “Standard” was total. Our native tongue was to be extirpated as rapidly as possible if we wanted any social advancement at all and in working class Glasgow in the 1960s and 1970s social advancement was a major item on many a personal agenda. The multilingualism now so much à la mode was never an issue. Implicitly we were indoctrinated with notions of transient bilingualism whose goal, like that of the 19th and 20th century social missionaries in the Celtic areas of Scotland (and elsewhere), was to teach us the English in order that we forget the Glaswegian.
This study attempts to introduce South Korea's unique experiences of civic operations made in Iraq and Lebanon. Koreans approached it with extreme caution since they are seeing…
Abstract
This study attempts to introduce South Korea's unique experiences of civic operations made in Iraq and Lebanon. Koreans approached it with extreme caution since they are seeing through two different lenses: “paying back syndrome” from the Korean War experiences is colliding with the “Vietnam syndrome” from the experiences of Vietnam War. Expanding its regional role through revitalizing PKOs is not an easy job for the ROK government despite the fact that President Lee has committed himself to increase its efforts since his campaign days. South Korea recently decided to send its KDX-II type destroyer to Somalia for joining the maritime peacekeeping while people in Korea strongly suspect that the Obama administration would soon request to send its troops to Afghanistan as a part of International Security Assistance Force (ISAF). As the Korean society is getting democratized, progressive NGOs have been opposing the government decision to send forces to assist the U.S. war efforts in Iraq and Afghanistan. It remains to be seen how President Lee persuades people to bear the burden and endure sacrifices. At least, four problems need to be addressed for Korea to become a major troop-contributing country (TCC): first, Korea needs to enact laws to deal with South Korea's participation in the UN PKOs. Second, Korea needs to find a way to include civilian experts in future activities of UN PKOs. Third, it needs to increase the budget and size of standby forces. Lastly, it needs to educate people to understand why Korea has to contribute further to make a safer world. It remains to be seen whether South Korea will continue to focus on its stabilization and reconstruction efforts without sending its combat troops.