42,498 research outputs found
Crafting networks to achieve, or not achieve, chaotic states
The influence of networks topology on collective properties of dynamical
systems defined upon it is studied in the thermodynamic limit. A network model
construction scheme is proposed where the number of links, the average
eccentricity and the clustering coefficient are controlled. This is done by
rewiring links of a regular one dimensional chain according to a probability
within a specific range , that can depend on the number of vertices .
We compute the thermodynamic behavior of a system defined on the network, the
rotors model, and monitor how it is affected by the topological changes.
We identify the network dimension as a crucial parameter: topologies with
d\textless{}2 exhibit no phase transitions while ones with d\textgreater{}2
display a second order phase transition. Topologies with exhibit states
characterized by infinite susceptibility and macroscopic chaotic/turbulent
dynamical behavior. These features are also captured by in the finite size
context
Causal inference taking into account unobserved confounding
Causal inference with observational data can be performed under an assumption
of no unobserved confounders (unconfoundedness assumption). There is, however,
seldom clear subject-matter or empirical evidence for such an assumption. We
therefore develop uncertainty intervals for average causal effects based on
outcome regression estimators and doubly robust estimators, which provide
inference taking into account both sampling variability and uncertainty due to
unobserved confounders. In contrast with sampling variation, uncertainty due
unobserved confounding does not decrease with increasing sample size. The
intervals introduced are obtained by deriving the bias of the estimators due to
unobserved confounders. We are thus also able to contrast the size of the bias
due to violation of the unconfoundedness assumption, with bias due to
misspecification of the models used to explain potential outcomes. This is
illustrated through numerical experiments where bias due to moderate unobserved
confounding dominates misspecification bias for typical situations in terms of
sample size and modeling assumptions. We also study the empirical coverage of
the uncertainty intervals introduced and apply the results to a study of the
effect of regular food intake on health. An R-package implementing the
inference proposed is available.Comment: Biometrics 201
Between eternity and actualization: the co-evolution of the fields of communication in the Vatican
Most research on structuration or the appropriation of ICT in organizations has put aside the problem of dyschronies. It has not taken into account the differences in nature, speed, and temporality of changes that co-exist within an organization. To address this limitation, the author of this paper suggests a model based on the theory of practice and neo-institutionalist perspectives, so as to make sense of the co-evolution of intra-organizational fields. This model, which proposes a balance between various institutional tensions, has been worked out inductively from a longitudinal case study on communication fields within the Roman Curia, the administrative headquarters of the Catholic Church located in the Vatican. These tensions are related to socio-technical, socio-theological, socio-organizational, and socio-economic areas. A set of propositions regarding the link between intra-organizational fields and tensions and the relationships between intra-organizational fields (parallel, convergent, and competing evolutions) is proposed.Keywords: Dyschronies; structuration; intra-organizational fields; communication; medias; ICT; Roman Curia
American and European social embeddedness in IS research: the case of structurational approaches.
Whether in Europe or in North America, Structuration Theory has been widely applied in Information System research. Looking at some structurationistsâ trajectories, it seems that European and American researchers correspond each to specific sub-theoretical streams. After having put forward institutional explanations of the overall dynamic, we suggest analysing the situation from an epistemological point of view: the various conceptions of management enacted by the different structurationist leaders. This results in the disappearance of the apparent continental dichotomy we first raised. As a conclusion, we propose two perspectives for the new European academy of management.Key-words: Structuration theory; social embeddedness of management research; research trajectories; epistemology
Strategic Alignment: What Else? A Practice Based View of IS Value.
Pour lâessentiel, les recherches traitant des valeurs stratĂ©giques du SI restent dans le paradigme de lâalignement stratĂ©gique, et utilisent des notions telles que celles de "processus" ou "dâactivitĂ©s". En sâappuyant sur la perspective offerte par les thĂ©ories de la pratique, cet article offre une alternative en distinguant trois formes de praxis et des valeurs spĂ©cifiques.Literature about IS strategic management or IS strategic value is abundant. Nonetheless, the bulk of existing studies are focused on the concept of alignment. They do not make sense of a strategic value "in practice" and still draw on notions such as activity or process to make sense of alignment. By means of a practice-based view of technology, three praxis are suggested here for the modeling of strategic value: legitimacy-related (based on adoption praxis), assimilative (related to design and acceptance praxis) and appropriative (linked to local adaptation and improvisation praxis). They are introduced by means of a "thought experiment" (a short story about a rifle).Strategic alignment; IS strategic value; Practice-based views; strategic value in practice; thought experiments;
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