We propose a preconditioned variant of the
modified HSS
(
MHSS
) iteration method for solving a class of complex symmetric systems of linear equations. Under suitable conditions, we prove the ...convergence of the
preconditioned MHSS
(
PMHSS
) iteration method and discuss the spectral properties of the PMHSS-preconditioned matrix. Numerical implementations show that the resulting PMHSS preconditioner leads to fast convergence when it is used to precondition Krylov subspace iteration methods such as GMRES and its restarted variants. In particular, both the stationary PMHSS iteration and PMHSS-preconditioned GMRES show meshsize-independent and parameter-insensitive convergence behavior for the tested numerical examples.
During the post-Reconstruction era in the United States, white southerners marked the cultural landscape with monuments and memorials honoring the Confederate cause and its heroes. These racialized ...symbols enjoyed an undisputed claim to public squares and parks throughout the South. It was not until the late twentieth century that commemorations to the black freedom struggle were publicly supported. This analysis examines the institutionalization of counter-memories of the civil rights movement in Memphis, Tennessee at the Lorraine Motel, the site of the assassination of Reverend Dr. Martin Luther King, Jr. The author draws on collective memory, cultural trauma, and social movements research as well as critical race theory to explain the creation of the National Civil Rights Museum. Using primary and secondary data sources the author examines how social memory agents, a changing political culture, and the passage of time mediated the cultural trauma of King's assassination and influenced the institutionalization of oppositional collective memories. Relying on Derrick Bell's interest-convergence principle, the author concludes that the creation of this major memorial museum was a result of the convergence of white and black interests, specifically the economic and political interests of white elites and the cultural and political interests of black symbolic entrepreneurs.
This article documents that the hydrogen economy continues to attract significant attention among politicians, the media, and some academics. We believe that an explanation lies in the way that the ...hydrogen economy fulfills psychological and cultural needs related to a future world where energy is abundant, cheap, and pollution-free, a “fantasy” that manifests itself with the idea that society can continue to operate without limits imposed by population growth and the destruction of the environment. The article begins by explaining its research methodology consisting of two literature reviews, research interviews of energy experts, and the application of symbolic convergence theory, a general communications theory about the construction of rhetorical fantasies. We then identify a host of socio-technical challenges to explain why the creation of a hydrogen economy would present immense (and possibly intractable) obstacles, an argument supplemented by our research interviews. Next, we employ symbolic convergence theory to identify five prevalent fantasy themes and rhetorical visions—independence, patriotism, progress, democratization, and inevitability—in academic and public discussions in favor of the hydrogen economy. We conclude by offering implications for scholarship relating to energy policy more broadly.
In this paper, enlightened by the effectiveness of Anderson acceleration (AA), a well‐established technique for accelerating fixed‐point solvers, we first present the Anderson accelerating ...modulus‐based matrix splitting (AAMS) algorithms for a class of horizontal nonlinear complementarity problems. Then, by introducing the strong semi‐smoothness of the absolute value function, we establish the local convergence theory of the AAMS algorithms. More importantly, we provide the optimal parameter for the AAMS algorithms, which is independent of iteration and applicable to other reduced MS algorithms. Finally, the numerical experiments are conducted to clarify the efficiency and practicability of the AAMS algorithms and its optimal parameter, and the effects of two parameters (both derived from AA) of the AAMS algorithms are analyzed.
In politics, ideas matter. They provide the foundation for economic policymaking, which in turn shapes what is possible in domestic and international politics. Yet until now, little attention has ...been paid to how these ideas are produced and disseminated, and how this process varies between countries.The National Origins of Policy Ideasprovides the first comparative analysis of how "knowledge regimes"-communities of policy research organizations like think tanks, political party foundations, ad hoc commissions, and state research offices, and the institutions that govern them-generate ideas and communicate them to policymakers.
John Campbell and Ove Pedersen examine how knowledge regimes are organized, operate, and have changed over the last thirty years in the United States, France, Germany, and Denmark. They show how there are persistent national differences in how policy ideas are produced. Some countries do so in contentious, politically partisan ways, while others are cooperative and consensus oriented. They find that while knowledge regimes have adopted some common practices since the 1970s, tendencies toward convergence have been limited and outcomes have been heavily shaped by national contexts.
Drawing on extensive interviews with top officials at leading policy research organizations, this book demonstrates why knowledge regimes are as important to capitalism as the state and the firm, and sheds new light on debates about the effects of globalization, the rise of neoliberalism, and the orientation of comparative political economy in political science and sociology.
The restricted version of the overlapping Schur complement (SchurRAS) preconditioner was introduced by Li and Saad (2006) for the solution of linear system Ax=b, and numerical results have shown that ...the SchurRAS method outperforms the restricted additive Schwarz (RAS) method both in terms of iteration count and CPU time. In this paper, based on meticulous derivation, we give an algebraic representation of the SchurRAS preconditioner, and prove that the SchurRAS method is convergent under the condition that A is an M-matrix and it converges faster than the RAS method.
One of the challenges that China currently faces is how to reduce the emissions of water pollution. However, the study of water pollution convergence has a certain policy significance for controlling ...the emissions of water pollution. This article firstly uses chemical oxygen demand (COD) and ammonia nitrogen (NH
3
–N) as indicators of water pollution. Due to the obvious spillover effect of water in space, this article adds a spatial effect to the convergence model. Based on panel data of 30 provinces and cities from 2006 to 2017, this article uses a dynamic spatial Dubin model to analyze the convergence of water pollution emission intensity to address the endogenous problem in the model. The empirical results of this paper show that there is absolute
β
-convergence and conditional
β
-convergence in the intensity of water pollution emissions. The spatial autocorrelation test shows that there is a positive spatial autocorrelation of water pollution emissions, which means that the pollution emissions in neighboring areas will affect the emissions in the local area. The industrial structure has a certain promoting effect on the emission of water pollution, which means that adjusting the industrial structure and alleviating the structure of the secondary industry is the trend of future development. Economic growth can curb the emissions of water pollution. The influences of urbanization and foreign investment on the emissions of the two pollutants are inconsistent, and policies can be formulated according to local conditions in the future.
The authors document and contrast changes (or lack thereof) in job stability over the past 25 years between Japan and the United States. Prime-age male workers with at least five years of tenure in ...Japan continued to enjoy much higher job stability than did their U.S. counterparts. Most remarkably, Japan’s “Lost Decade” had little discernible adverse effect on the job stability of this group of Japanese employees. By contrast, job stability for mid-career hires and youth workers deteriorated in Japan. The authors’ cross-national regression analysis of job loss confirms the consistently more important role that seniority plays in protecting workers from job loss in Japan than in the United States and reveals that this gap in seniority’s influence on job stability between the two countries widened. Overall, it is the U.S. economy with the longest economic expansion, not the Japanese economy with the longest economic stagnation, that experienced deteriorating job stability, pointing to the absence of convergence of the Japanese and U.S. systems.
A complex system of linear equations arises in many important applications. We further explore algebraic and convergence properties and present analytical and numerical comparisons among several ...available iteration methods such as C-to-R and PMHSS for solving such a class of linear systems. Theoretical analyses and computational results show that reformulating a complex linear system into an equivalent real form is a feasible and effective approach, for which we can construct, analyze, and implement accurate, efficient, and robust preconditioned iteration methods.
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