5,424 research outputs found
Institutional complexity and paradox theory: complementarities of competing demands
Organizational success increasingly depends on leaders’ abilities to address competing demands simultaneously. Scholars have applied both institutional theory and paradox theory to better understand the nature and responses to these competing demands. These two lenses diverge in their understanding and responses to tensions. Institutional theory depicts competing demands emerging from divergent field-level pressures and stresses their contradictory and oppositional nature. Organizational responses vary from making tradeoffs and choosing pressures with which to conform to seeking strategies for engaging both and managing conflict. Paradox theory locates competing demands as inherent with organizational systems, surfaced through environmental conditions, individual sensemaking, or relational dialogue. According to these scholars, paradoxes are contradictory, interdependent, and persist over time, demanding strategies for engaging and accommodating tensions but not resolving them. In this essay, we highlight these distinctions and argue that drawing from both of these lenses will results in rich, generative theorizing to better address key challenges in the world. We identify specific areas where future research can benefit from such integration
Neglected heterogeneity in moment condition models
The central concern of this paper is parameter heterogeneity in models specified by a number of unconditional or conditional moment conditions and thereby the provision of a framework for the development of apposite optimal -tests against its potential presence. We initially consider the unconditional moment restrictions framework. Optimal -tests against moment condition parameter heterogeneity are derived with the relevant Jacobian matrix obtained in terms of the second order own derivatives of the moment indicator in a leading case. GMM and GEL tests of specification based on generalized information matrix equalities appropriate for moment-based models are described and their relation to optimal -tests against moment condition parameter heterogeneity examined. A fundamental and important difference is noted between GMM and GEL constructions. The paper is concluded by a generalization of these tests to the conditional moment context and the provision of a limited set of simulation experiments to illustrate the efficacy of the proposed tests
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Adding complexity to theories of paradox, tensions, and dualities of innovation and change: introduction to Organization Studies Special Issue on paradox, tensions, and dualities of innovation and change
Approaches to paradox have deep historical roots. Eastern philosophers such as Lao Tzu and Confucius described the world as a mystical interplay of interdependent contradictions (Chen, 2002; Li, 2014). The Tao te Ching, for example, opens with the puzzling and circular first line, “The Tao that can be told is not the eternal Tao.” Western scholars such as Aristotle and Hegel depicted paradox as irrational and unsolvable puzzles or double binds. The classic example is the liar’s paradox, with the statement “I am lying” leading one in strange loops between honesty and falsehood. Both these traditions stress that our greatest insights derive from grappling with intricate, interwoven and often irrational contradiction
The Herschel Exploitation of Local Galaxy Andromeda (HELGA) II: Dust and Gas in Andromeda
We present an analysis of the dust and gas in Andromeda, using Herschel
images sampling the entire far-infrared peak. We fit a modified-blackbody model
to ~4000 quasi-independent pixels with spatial resolution of ~140pc and find
that a variable dust-emissivity index (beta) is required to fit the data. We
find no significant long-wavelength excess above this model suggesting there is
no cold dust component. We show that the gas-to-dust ratio varies radially,
increasing from ~20 in the center to ~70 in the star-forming ring at 10kpc,
consistent with the metallicity gradient. In the 10kpc ring the average beta is
~1.9, in good agreement with values determined for the Milky Way (MW). However,
in contrast to the MW, we find significant radial variations in beta, which
increases from 1.9 at 10kpc to ~2.5 at a radius of 3.1kpc and then decreases to
1.7 in the center. The dust temperature is fairly constant in the 10kpc ring
(ranging from 17-20K), but increases strongly in the bulge to ~30K. Within
3.1kpc we find the dust temperature is highly correlated with the 3.6 micron
flux, suggesting the general stellar population in the bulge is the dominant
source of dust heating there. At larger radii, there is a weak correlation
between the star formation rate and dust temperature. We find no evidence for
'dark gas' in M31 in contrast to recent results for the MW. Finally, we
obtained an estimate of the CO X-factor by minimising the dispersion in the
gas-to-dust ratio, obtaining a value of (1.9+/-0.4)x10^20 cm^-2 [K kms^-1]^-1.Comment: 19 pages, 18 figures. Submitted to ApJ April 2012; Accepted July 201
Preliminary Limits on the WIMP-Nucleon Cross Section from the Cryogenic Dark Matter Search (CDMS)
We are conducting an experiment to search for WIMPs, or weakly-interacting
massive particles, in the galactic halo using terrestrial detectors. This
generic class of hypothetical particles, whose properties are similar to those
predicted by extensions of the standard model of particle physics, could
comprise the cold component of non-baryonic dark matter. We describe our
experiment, which is based on cooled germanium and silicon detectors in a
shielded low-background cryostat. The detectors achieve a high degree of
background rejection through the simultaneous measurement of the energy in
phonons and ionization. Using exposures on the order of one kilogram-day from
initial runs of our experiment, we have achieved (preliminary) upper limits on
the WIMP-nucleon cross section that are comparable to much longer runs of other
experiments.Comment: 5 LaTex pages, 5 eps figs, epsf.sty, espcrc2dsa2.sty. Proceedings of
TAUP97, Gran Sasso, Italy, 7-11 Sep 1997, Nucl. Phys. Suppl., A. Bottino, A.
di Credico and P. Monacelli (eds.). See also http://cfpa.berkeley.ed
PI controller tuning for load disturbance rejection using constrained optimization
© 2016, Springer-Verlag Berlin Heidelberg. In this paper, a simple and effective PI controller tuning method is presented. To take both performance requirements and robustness issues into consideration, the design technique is based on optimization of load disturbance rejection with a constraint either on the gain margin or phase margin. In addition, a simplified form of the resulting tuning formulae is obtained for first order plus dead time models. To demonstrate the ability of the proposed tuning technique in dealing with a wide range of plants, simulation results for several examples, including integrating, non-minimum phase and long dead time models, are provided
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