1,382 research outputs found
On Multistage Learning a Hidden Hypergraph
Learning a hidden hypergraph is a natural generalization of the classical
group testing problem that consists in detecting unknown hypergraph
by carrying out edge-detecting tests. In the given paper we
focus our attention only on a specific family of localized
hypergraphs for which the total number of vertices , the number of
edges , , and the cardinality of any edge ,
. Our goal is to identify all edges of by
using the minimal number of tests. We develop an adaptive algorithm that
matches the information theory bound, i.e., the total number of tests of the
algorithm in the worst case is at most . We also discuss
a probabilistic generalization of the problem.Comment: 5 pages, IEEE conferenc
Nonclassical Moments and their Measurement
Practically applicable criteria for the nonclassicality of quantum states are
formulated in terms of different types of moments. For this purpose the moments
of the creation and annihilation operators, of two quadratures, and of a
quadrature and the photon number operator turn out to be useful. It is shown
that all the required moments can be determined by homodyne correlation
measurements. An example of a nonclassical effect that is easily characterized
by our methods is amplitude-squared squeezing.Comment: 12 pages, 6 figure
Soviet Power and System of Public Education in 1920s: Practice of Experiments in Conditions of Building New Statehood
The state policy of the Soviet government in relation to the system of public education in the initial period of the formation of the Soviet state is considered. The relevance of the study is due to the content and organizational side of the transformations of the Soviet power in the field of public education in the 1920s, which is today of substantive interest for modern education from the applied standpoint of pedagogical practices and innovations in terms of their effectiveness and professional suitability. The authors focus on the general nature of managerial experiments that took place in the school system in the 1920s in the context of the general transformation of the country. A detailed analysis of the organizational foundations of the reform of the education system was carried out, the structure of educational institutions of the period under review was studied, its graphical diagram was built, an overview of the content and overview of school education was made. The novelty of the research lies in the presented subject analysis of the content of curricula and school programs of the 1920s, the construction of a consistent line of reforms in education implemented by the Soviet government in the context of their further effectiveness and historical results. Conclusions are made about the content side of these transformations within the framework of a complex of pedagogical ideas and new practices in education
Transmission electron microscopy investigation of segregation and critical floating-layer content of indium for island formation in InGaAs
We have investigated InGaAs layers grown by molecular-beam epitaxy on
GaAs(001) by transmission electron microscopy (TEM) and photoluminescence
spectroscopy. InGaAs layers with In-concentrations of 16, 25 and 28 % and
respective thicknesses of 20, 22 and 23 monolayers were deposited at 535 C. The
parameters were chosen to grow layers slightly above and below the transition
between the two- and three-dimensional growth mode. In-concentration profiles
were obtained from high-resolution TEM images by composition evaluation by
lattice fringe analysis. The measured profiles can be well described applying
the segregation model of Muraki et al. [Appl. Phys. Lett. 61 (1992) 557].
Calculated photoluminescence peak positions on the basis of the measured
concentration profiles are in good agreement with the experimental ones.
Evaluating experimental In-concentration profiles it is found that the
transition from the two-dimensional to the three-dimensional growth mode occurs
if the indium content in the In-floating layer exceeds 1.1+/-0.2 monolayers.
The measured exponential decrease of the In-concentration within the cap layer
on top of the islands reveals that the In-floating layer is not consumed during
island formation. The segregation efficiency above the islands is increased
compared to the quantum wells which is explained tentatively by
strain-dependent lattice-site selection of In. In addition, In0.25Ga0.75As
quantum wells were grown at different temperatures between 500 oC and 550 oC.
The evaluation of concentration profiles shows that the segregation efficiency
increases from R=0.65 to R=0.83.Comment: 16 pages, 6 figures, 1 table, sbmitted in Phys. Rev.
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