74,249 research outputs found
Does the Market Pay Off? Earnings Inequality and Returns to Education in Urban China
The paper examines earnings inequality and earnings returns to education in China among four types of workers characterized by their labor market history. Compared to workers staying in the state sector, early market entrants no longer enjoyed advantages. The commonly observed higher earnings returns to education in the market sector are only limited to recent market entrants. This results from the aggregation of two very different types of workers: those who were "pushed" and those who "jumped" into the market in later stage of the reform. The findings challenge the prevailing wisdom that education is necessarily more highly rewarded by the market sector.http://deepblue.lib.umich.edu/bitstream/2027.42/39838/3/wp454.pd
A Unified Relay Framework with both D-F and C-F Relay Nodes
Decode-and-forward (D-F) and compress-and-forward (C-F) are two fundamentally
different relay strategies proposed by (Cover and El Gamal, 1979).
Individually, either of them has been successfully generalized to multi-relay
channels. In this paper, to allow each relay node the freedom of choosing
either of the two strategies, we propose a unified framework, where both the
D-F and C-F strategies can be employed simultaneously in the network. It turns
out that, to fully incorporate the advantages of both the best known D-F and
C-F strategies into a unified framework, the major challenge arises as follows:
For the D-F relay nodes to fully utilize the help of the C-F relay nodes,
decoding at the D-F relay nodes should not be conducted until all the blocks
have been finished; However, in the multi-level D-F strategy, the upstream
nodes have to decode prior to the downstream nodes in order to help, which
makes simultaneous decoding at all the D-F relay nodes after all the blocks
have been finished inapplicable. To tackle this problem, nested blocks combined
with backward decoding are used in our framework, so that the D-F relay nodes
at different levels can perform backward decoding at different frequencies. As
such, the upstream D-F relay nodes can decode before the downstream D-F relay
nodes, and the use of backward decoding at each D-F relay node ensures the full
exploitation of the help of both the other D-F relay nodes and the C-F relay
nodes. The achievable rates under our unified relay framework are found to
combine both the best known D-F and C-F achievable rates and include them as
special cases
Geometry effects in confined space
In this paper we calculate some exact solutions of the grand partition
functions for quantum gases in confined space, such as ideal gases in two- and
three-dimensional boxes, in tubes, in annular containers, on the lateral
surface of cylinders, and photon gases in three-dimensional boxes. Based on
these exact solutions, which, of course, contain the complete information about
the system, we discuss the geometry effect which is neglected in the
calculation with the thermodynamic limit , and analyze the
validity of the quantum statistical method which can be used to calculate the
geometry effect on ideal quantum gases confined in two-dimensional irregular
containers. We also calculate the grand partition function for phonon gases in
confined space. Finally, we discuss the geometry effects in realistic systems.Comment: Revtex,15 pages, no figur
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