Tensorized block rational Krylov methods for tensor Sylvester equations

We introduce the definition of tensorized block rational Krylov subspaces and its relation with multivariate rational functions, extending the formulation of tensorized Krylov subspaces introduced in [Kressner D., Tobler C., Krylov subspace methods for linear systems with tensor product structure, SIMAX, 2010]. Moreover, we develop methods for the solution of tensor Sylvester equations with low multilinear or Tensor Train rank, based on projection onto a tensor block rational Krylov subspace. We provide a convergence analysis, some strategies for pole selection, and techniques to efficiently compute the residual.Comment: 22 pages, 6 figures, 3 table

Entrepreneurial education : exploring the micro-dynamics of learning in student business incubators

In contribution to the literature on learning entrepreneurship through practice (Neck and Greene, 2011), in this study we conduct an ethnography of a student enterprise incubator. The latter combines aspects of practice-based learning with physical proximity to peers and mentors. Following nine months of observations, interviews, archival documents collection (email, Facebook pages) and participation to the activities of the incubator, we can report on the micro-dynamics in this environment. Our insights reveals that students peer-learning in the very early stages of the entrepreneurial process (idea exploration and feasibility studies) is underpinned by (a) unplanned interactions facilitated by (a1) close physical proximity as well as (1b) the perception of commonalities that do not lead to direct competition, as well as (2) a shared, newly acquired entrepreneurial identity facilitated by the symbolism and discourse that characterizes the environment (awards, photographs of individuals, etc.). Whilst the aforementioned interactions and the resulting mutually beneficial exchanges create a culture of generosity and mutual support, drawbacks are observed in the form of identity-focused behavior, whereby students become sidetracked by protecting their “entrepreneur” status and stop experimenting with their entrepreneurial journey, thus not progressing on their learning on the same. Overcoming the entrepreneurial-identity focus is key for continuous learning to occur for students in the business incubator. Students who overcome the latter develop an understanding that sustained entrepreneurial efforts can only be achieved through learning from setbacks. Over time and through repeated exposure to each-other’s failures as well as successes, a culture of effortful practice replaces the focus on entrepreneurial identity. It is this duality of effortful practice versus entrepreneurial identity that underpins continuous learning in the student business incubator

Stability, accuracy and efficiency of a semi-implicit method for three-dimensional shallow water flow

AbstractThe stability analysis, the accuracy and the efficiency of a semi-implicit finite difference scheme for the numerical solution of a three-dimensional shallow water model are presented and discussed. The governing equations are the three-dimensional Reynolds equations in which pressure is assumed to be hydrostatic. The pressure gradient in the momentum equations and the velocities in the vertically integrated continuity equation are discretized with the θ-method, with θ being an implicitness parameter. It is shown that the method is stable for 12 ≤ θ ≤ 1, unstable for θ < 12 and highest accuracy and efficiency is achieved when θ = 12. The resulting algorithm is mass conservative and naturally allows for the simulation of flooding and drying of tidal flats

Studio di affidabilità di celle in CdTe con prototipazione di una scheda di test per stress a lungo termine

Questa tesi tratta i meccanismi di degrado delle celle in CdTe. Una prima parte del lavoro riguarda la caratterizzazione delle celle tramite IV light e dark, EQE e OCVD. Una seconda parte consta di stress termici di durata variabile con una successiva caratterizzazione della cella. La parte finale è dedicata all'allestimento di un banco di misura automatizzato, realizzato tramite la progettazione di una matrice di relè, che permette il controllo da remoto di più canali di misura.openEmbargo temporaneo per motivi di segretezza e/o di proprietà dei risultati e/o informazioni sensibil

Les « procédés de distanciation » : une rupture nécessaire à la fiction brève d’horreur

As many specialists have shown, the haunting quality of the short-story is to be found in its literary genre itself : not only does it frighten the reader but it may also haunt him after the reading process. The form of the short story is indeed powerful as it is a suggestive form of literature but it can also be powerful when it comes to its fictional genre. Oneof the favorite fictional genres amongst short-stories\u27 writers seems to be the gothic one and this paper aims at demonstrating that a break from this kind of fiction is needed in order to help the reader to fully appreciate his reading. Focusing on Edgar Allan Poe and Roald Dahl\u27s short-stories, this article will first attempt to give a definition of the gothic genre in order to better situate our readers. Then, the second part of this study will endeavor to show that although it may not seem initially obvious, the works of the two authors under study share not only one but many characteristics, especially gothic ones. Finally, the present study will try to demonstrate that authors need to use some « procédés de distanciation »(according to Vincent Jouve\u27s terms) in order to encourage the reader to take a critical distance from the fiction and remind him that what he is reading is just fiction

Making internationalisation decisions: how heuristics and biases affect the reasoning processes of leaders of small and medium-sized firms

This thesis presents an exploration of how biases stemming from the use of heuristic-‐based reasoning processes influence the internationalisation decisions made by the leaders of Small and Medium-‐Sized Enterprises (SMEs). Three types of internationalisation decisions are specifically addressed in this thesis, namely foreign market selection, entry mode and foreign market exit. The empirical context is that of Scottish SMEs from three main industries, namely Environmental and Recycling, Oil and Gas, and Textiles. Each of the case firms is involved in value-‐adding activities across national borders. The theoretical context is that of internationalising SMEs. The thesis draws on three main strands of the internationalisation literature: the Transaction Cost Approach, the Process Theory of Internationalisation and the International New Venture (INV) approaches. In investigating the decisional processes involved in internationalisation, the thesis takes a Bounded Rationality stance and assumes the use of Heuristics-‐based reasoning (Tversky and Kahneman, 1974) in internationalisation decisions. The level of analysis is the individual decision maker within the internationalising firm. The unit of analysis is the internationalisation decision, which is explored from a reasoning process perspective. A case study strategy is used. Data collection tools are semi-‐structured interviews and repertory grid elicitation. The data is analysed inductively through the construction of causal-‐cognitive maps. Findings show that heuristics are a useful tool to explain the reasoning processes employed in internationalisation decisions. The contribution that this thesis makes to extant literature on the internationalisation of smaller firms is threefold. Firstly, the thesis outlines the processes involved in an array of internationalisation decisions (country selection, entry mode, exit decisions) underpinning the cross-‐national border behaviour of firms. Secondly, by observing the processes of decision-‐making through a cognitive lens, the thesis contributes to the emerging cognitive approach in internationalisation. Thirdly, the thesis contributes to the literature on international entrepreneurial experience by explaining how experiential and vicarious knowledge are leveraged and used in the process of internationalisation decision-‐making. III Propositions are advanced and further research is invited to progress current understanding of the making of internationalisation decisions in SMEs

Macabre Short Stories by Edgar Allan Poe and Roald Dahl

Focusing on Edgar Allan Poe and Roald Dahl’s short-stories, this paper’s main framework aims at demonstrating that although it may not seem initially obvious, the works of the two authors share not only one, but many characteristics. Before writing his famous children’s fiction, Roald Dahl established his reputation as a writer of deathly short stories with unexpected twists that may recall Poe’s Gothic tales. Therefore Dahl, who has never been considered part of the Neo-Gothic stream, has nevertheless incorporated Neo-Gothic elements in his work. The first part of this paper will focus on the Gothic genre of the two authors (and its characteristics) as it appears to be their common playground. In the second part of this study, the theme of the tortured body will be treated and will attempt to highlight the idea that the body, in Poe’s and Dahl’s works, stands for an externalization of the narrators’ tortured minds

On the mechanism of the cyclonic circulation in the Gulf of Tonkin in the summer

Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 113 (2008): C09029, doi:10.1029/2007JC004208.The circulation in the Gulf of Tonkin had been traditionally considered to be anticyclonic in the summer. This view was challenged recently by results from reanalyzing observational data, which clearly revealed that the circulation is cyclonic in all seasons. The surface wind stress is monsoonal, southwesterly in the summer and reversed in the winter. It remains unexplained why the circulation is always cyclonic, while the surface forcing reverses seasonally. In this study, we hypothesize that the inflow through Qiongzhou Strait, a shallow and narrow channel between Hainan Island and the Chinese mainland, is responsible for maintaining the cyclonic circulation in the summer. Besides the requirements of mass conservation and bathymetry constraint, this flow, even with a rather small transport, carries a considerable amount of potential vorticity (PV) into the gulf, and the integral constraint of PV requires the presence of a frictional torque to be associated with a cyclonic circulation. Several numerical experiments with a three-dimensional model have been conducted to test this hypothesis. When the westward flow through Qiongzhou Strait is blocked, the model simulates an anticyclonic circulation in the summer. When the westward flow through Qiongzhou Strait is allowed, the circulation changes to a cyclonic one, consistent with our hypothesis.This study is supported by the National Basic Research Program of China under contract 2005CB422302 and 2007CB411804, the key project of the International Science and Technology Cooperation program of China under contract 2006DFB21250, and the 111 project under contract B07036