35,832 research outputs found
Reformulation in planning
Reformulation of a problem is intended to make the problem more amenable to efficient solution. This is equally true in the special case of reformulating a planning problem. This paper considers various ways in which reformulation can be exploited in planning
Polynomial Cointegration among Stationary Processes with Long Memory
n this paper we consider polynomial cointegrating relationships among
stationary processes with long range dependence. We express the regression
functions in terms of Hermite polynomials and we consider a form of spectral
regression around frequency zero. For these estimates, we establish consistency
by means of a more general result on continuously averaged estimates of the
spectral density matrix at frequency zeroComment: 25 pages, 7 figures. Submitted in August 200
Towards practice-based studies of HRM: an actor-network and communities of practice informed approach
HRM may have become co-terminus with the new managerialism in the rhetorical orthodoxies of the HRM textbooks and other platforms for its professional claims. However, we have detailed case-study data showing that HR practices can be much more complicated, nuanced and indeed resistive toward management within organizational settings.
Our study is based on ethnographic research, informed by actor-network theory and community of practice theory conducted by one of the authors over an 18-month period. Using actor-network theory in a descriptive and critical way, we analyse practices of managerial resistance, enrolment and counter-enrolment through which an unofficial network of managers used a formal HRM practice to successfully counteract the official strategy of the firm, which was to close parts of a production site. As a consequence, this network of middle managers effectively changed top management strategy and did so through official HRM practices, coupled with other actor-network building processes, arguably for the ultimate benefit of the organization, though against the initial views of the top management.
The research reported here, may be characterized as a situated study of HRM-in-practice and we draw conclusions which problematize the concept of HRM in contemporary management literature
Ab-initio study of the bandgap engineering of Al(1-x)Ga(x)N for optoelectronic applications
A theoretical study of Al(1-x)Ga(x)N, based on full-potential linearized
augmented plane wave method, is used to investigate the variations in the
bandgap, optical properties and non-linear behavior of the compound with the
variation of Ga concentration. It is found that the bandgap decreases with the
increase of Ga in Al(1-x)Ga(x)N. A maximum value of 5.5 eV is determined for
the bandgap of pure AlN which reaches to minimum value of 3.0 eV when Al is
completely replaced by Ga. The static index of refraction and dielectric
constant decreases with the increase in bandgap of the material, assigning a
high index of refraction to pure GaN when compared to pure AlN. The refractive
index drops below 1 for photon energies larger than 14 eV results group
velocity of the incident radiation higher than the vacuum velocity of light.
This astonishing result shows that at higher energies the optical properties of
the material shifts from linear to non-linear. Furthermore, frequency dependent
reflectivity and absorption coefficients show that peak value of the absorption
coefficient and reflectivity shifts towards lower energy in the UV spectrum
with the increase in Ga concentration. This comprehensive theoretical study of
the optoelectronic properties of the alloys is presented for the first time
which predicts that the material can be effectively used in the optical devices
working in the visible and UV spectrum.Comment: 18 pages, 7 figure
Economic Crisis and Reform in Bulgaria, 1989-92
Bulgaria\u27s economy began a deep and prolonged collapse in 1989, exactly one hundred years after the noted Bulgarian novelist Ivan Vazov published his stirring novel opposing the tyranny of the Ottomans and warning of the mistaken road of socialism. The 1989 collapse was partially a reflection of the external political upheavals among Bulgaria\u27s trading partners in Eastern Europe, which were rejecting socialist principles. But it was also a reflection of the weaknesses imbedded in the economy after 30 years of central planning. Political instability within Bulgaria, market reforms, and attempts at privatization contributed further to economic uncertainty resulting in a continued output decline. The almost thirty percent fall in real Gross Domestic Product ( GDP ) over the period 1989-1992 left approximately one-half million workers unemployed, and many more underemployed in this country of approximately nine million people
Clique minors in graphs with a forbidden subgraph
The classical Hadwiger conjecture dating back to 1940's states that any graph
of chromatic number at least has the clique of order as a minor.
Hadwiger's conjecture is an example of a well studied class of problems asking
how large a clique minor one can guarantee in a graph with certain
restrictions. One problem of this type asks what is the largest size of a
clique minor in a graph on vertices of independence number at
most . If true Hadwiger's conjecture would imply the existence of a clique
minor of order . Results of Kuhn and Osthus and Krivelevich and
Sudakov imply that if one assumes in addition that is -free for some
bipartite graph then one can find a polynomially larger clique minor. This
has recently been extended to triangle free graphs by Dvo\v{r}\'ak and
Yepremyan, answering a question of Norin. We complete the picture and show that
the same is true for arbitrary graph , answering a question of Dvo\v{r}\'ak
and Yepremyan. In particular, we show that any -free graph has a clique
minor of order , for some constant
depending only on . The exponent in this result is tight up to a
constant factor in front of the term.Comment: 11 pages, 1 figur
Perturbation theory for a stochastic process with Ornstein-Uhlenbeck noise
The Ornstein-Uhlenbeck process may be used to generate a noise signal with a
finite correlation time. If a one-dimensional stochastic process is driven by
such a noise source, it may be analysed by solving a Fokker-Planck equation in
two dimensions. In the case of motion in the vicinity of an attractive fixed
point, it is shown how the solution of this equation can be developed as a
power series. The coefficients are determined exactly by using algebraic
properties of a system of annihilation and creation operators.Comment: 7 pages, 0 figure
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