Solving seismic wave propagation in elastic media using the matrix exponential approach

Three numerical algorithms are proposed to solve the time-dependent elastodynamic equations in elastic solids. All algorithms are based on approximating the solution of the equations, which can be written as a matrix exponential. By approximating the matrix exponential with a product formula, an unconditionally stable algorithm is derived that conserves the total elastic energy density. By expanding the matrix exponential in Chebyshev polynomials for a specific time instance, a so-called ``one-step'' algorithm is constructed that is very accurate with respect to the time integration. By formulating the conventional velocity-stress finite-difference time-domain algorithm (VS-FDTD) in matrix exponential form, the staggered-in-time nature can be removed by a small modification, and higher order in time algorithms can be easily derived. For two different seismic events the accuracy of the algorithms is studied and compared with the result obtained by using the conventional VS-FDTD algorithm.Comment: 13 pages revtex, 6 figures, 2 table

70 Years Since the Liberation of the Netherlands From Memory to Remembrance

On 16 October 2014, the Canadian War Museum partnered with the Embassy of the Kingdom of the Netherlands to host the first in the Embassy’s national series of lectures “From Memory to Remembrance” in the Museum’s Barney Danson Theatre. The Embassy launched the series in the fall of 2014, with subsequent events in February and April 2015, with Canadian and Dutch scholars helping the audience to follow the Canadian military campaign from the Battle of the Scheldt to the German capitulation at Wageningen on 5 May 1945. Attended by His Excellency Governor General David Johnston, the Ottawa event featured Terry Copp, Wilfrid Laurier University, who lectured on how the Canadians’ major engagements in the Scheldt Battle unfolded, and Ben Schoenmaker of the University of Leiden and Netherlands Institute of Military History, who spoke to the Dutch perspective of the 1944-1945 battles and views of the liberating forces. Dean Oliver, Director of Research at the Canadian Museum of History moderated. On 26 February 2015, the University of Calgary hosted the second instalment of the series, moderated by David Bercuson and featuring Canadian historian Mark Zuehlke and Erwin van Loo, Senior Research Fellow at the Dutch Institute for Military History. The final instalment in the series took place in Fredericton on 1 April 2015, in partnership with the Gregg Centre for the Study of War and Society, and featured the Centre’s Deputy Director, Lee Windsor, and Lieutenant-Colonel Wouter Hagemeijer, Assistant Professor at the Netherlands Defence Academy. The event was moderated by Marc Milner, the Gregg Centre’s director. His Excellency Cees Kole, Ambassador of the Netherlands to Canada, opened the first event in the series Ambassador Kole joined the Netherlands’ Ministry of Foreign Affairs in 1984. Before his posting to Ottawa in 2013, he served in diplomatic postings in Warsaw, Brussels, Paris, and as ambassador to Iran. The ambassador’s speech opening the From Memory to Remembrance series offers some interesting insights into the interplay between lived experiences, history, and remembrance, as well as highlighting the many connections between Canada and the Netherlands, which the presenters in the series further underlined. The speech is reproduced in full below

Vortex of the Web. Potentials of the online environment

This volume compiles international contributions that explore the potential risks and chances coming along with the wide-scale migration of society into digital space. Suggesting a shift of paradigm from Spiral of Silence to Nexus of Noise, the opening chapter provides an overview on systematic approaches and mechanisms of manipulation – ranging from populist political players to Cambridge Analytica. After a discussion of the the juxtaposition effects of social media use on social environments, the efficient instrumentalization of Twitter by Turkish politicans in the course of the US-decision to recognize Jerusalem as Israel’s capital is being analyzed. Following a case study of Instagram, Black Lives Matter and racism is a research about the impact of online pornography on the academic performance of university students. Another chapter is pointing out the potential of online tools for the successful relaunch of shadow brands. The closing section of the book deals with the role of social media on the opinion formation about the Euromaidan movement during the Ukrainian revolution and offers a comparative study touching on Russian and Western depictions of political documentaries in the 2000s

Roots Reloaded. Culture, Identity and Social Development in the Digital Age

This edited volume is designed to explore different perspectives of culture, identity and social development using the impact of the digital age as a common thread, aiming at interdisciplinary audiences. Cases of communities and individuals using new technology as a tool to preserve and explore their cultural heritage alongside new media as a source for social orientation ranging from language acquisition to health-related issues will be covered. Therefore, aspects such as Art and Cultural Studies, Media and Communication, Behavioral Science, Psychology, Philosophy and innovative approaches used by creative individuals are included. From the Aboriginal tribes of Australia, to the Maoris of New Zealand, to the mystical teachings of Sufi brotherhoods, the significance of the oral and written traditions and their current relation to online activities shall be discussed in the opening article. The book continues with a closer look at obesity awareness support groups and their impact on social media, Facebook usage in language learning context, smartphone addiction and internet dependency, as well as online media reporting of controversial ethical issues. The Digital progress has already left its dominating mark as the world entered the 21st century. Without a doubt, as technology continues its ascent, society will be faced with new and altering values in an effort to catch-up with this extraordinary Digitization, adapt satisfactorily in order to utilize these strong developments in everyday life

Multimodal Interaction in a Haptic Environment

In this paper we investigate the introduction of haptics in a multimodal tutoring environment. In this environment a haptic device is used to control a virtual piece of sterile cotton and a virtual injection needle. Speech input and output is provided to interact with a virtual tutor, available as a talking head, and a virtual patient. We introduce the haptic tasks and how different agents in the multi-agent system are made responsible for them. Notes are provided about the way we introduce an affective model in the tutor agent

clicktatorship and democrazy: Social media and political campaigning

This chapter aims to direct attention to the political dimension of the social media age. Although current events like the Cambridge Analytica data breach managed to raise awareness for the issue, the systematically organized and orchestrated mechanisms at play still remain oblivious to most. Next to dangerous monopoly-tendencies among the powerful players on the market, reliance on automated algorithms in dealing with content seems to enable large-scale manipulation that is applied for economical and political purposes alike. The successful replacement of traditional parties by movements based on personality cults around marketable young faces like Emmanuel Macron or Austria’s Sebastian Kurz is strongly linked to products and services offered by an industry that simply provides likes and followers for cash. Inspired by Trump’s monopolization of the Twitter-channel, these new political acteurs use the potential of social media for effective message control, allowing them to avoid confrontations with professional journalists. In addition, an extremely active minority of organized agitators relies on the viral potential of the web to strongly influence and dictate public discourse – suggesting a shift from the Spiral of Silence to the dangerous illusion of a Nexus of Noise

FARM ORGANIZATION OPTIONS

This paper is a summary of the management implications to consider when choosing among multiple owner farm business organizations. These include joint operating agreements, partnerships, limited liability companies and corporations, both subchapter C and subchapter S. We assume the reader has some familiarity with income tax laws and legal terminology.Farm Management,

A nonlinear Bloch model for Coulomb interaction in quantum dots

In this paper we first derive a Coulomb Hamiltonian for electron--electron interaction in quantum dots in the Heisenberg picture. Then we use this Hamiltonian to enhance a Bloch model, which happens to be nonlinear in the density matrix. The coupling with Maxwell equations when interaction with an electromagnetic field is also considered from the Cauchy problem point of view. The study is completed by numerical results and a discussion about the advisability of neglecting intra-band coherences, as is done in part of the literature.Comment: 17 pages. Journal of Mathematical Physics (2014) \`a para\^itr