15,993 research outputs found
A parallel Euler approach for large-scale biological sequence assembly
Biological sequence assembly is an essential step for sequencing the genomes of organisms. Sequence assembly is very computing intensive especially for the large-scale sequence assembly. Parallel computing is an effective way to reduce the computing time and support the assembly for large amount of biological fragments. Euler sequence assembly algorithm is an innovative algorithm proposed recently. The advantage of this algorithm is that its computing complexity is polynomial and it provides a better solution to the notorious “repeat” problem. This paper introduces the parallelization of the Euler sequence assembly algorithm. All the Genome fragments generated by whole genome shotgun (WGS) will be assembled as a whole rather than dividing them into groups which may incurs errors due to the inaccurate group partition. The implemented system can be run on supercomputers, network of workstations or even network of PC computers. The experimental results have demonstrated the performance of our system.<br /
Profitability of contrarian strategies in the Chinese stock market
This paper reexamines the profitability of loser, winner and contrarian
portfolios in the Chinese stock market using monthly data of all stocks traded
on the Shanghai Stock Exchange and Shenzhen Stock Exchange covering the period
from January 1997 to December 2012. We find evidence of short-term and
long-term contrarian profitability in the whole sample period when the
estimation and holding horizons are 1 month or longer than 12 months and the
annualized returns of contrarian portfolios increases with the estimation and
holding horizons. We perform subperiod analysis and find that the long-term
contrarian effect is significant in both bullish and bearish states while the
short-term contrarian effect disappears in bullish states. We compare the
performance of contrarian portfolios based on different grouping manners in the
estimation period and unveil that decile grouping outperforms quintile grouping
and tertile grouping, which is more evident and robust in the long run.
Generally, loser portfolios and winner portfolios have positive returns and
loser portfolios perform much better than winner portfolios. Both loser and
winner portfolios in bullish states perform better than those in the whole
sample period. In contrast, loser and winner portfolios have smaller returns in
bearish states in which loser portfolio returns are significant only in the
long term and winner portfolio returns become insignificant. These results are
robust to the one-month skipping between the estimation and holding periods and
for the two stock exchanges. Our findings show that the Chinese stock market is
not efficient in the weak form. These findings also have obvious practical
implications for financial practitioners.Comment: 24 pages (including 4 figures and 9 tables) + 5 supplementary figures
+ 10 supplementary table
Time-varying return predictability in the Chinese stock market
China's stock market is the largest emerging market all over the world. It is
widely accepted that the Chinese stock market is far from efficiency and it
possesses possible linear and nonlinear dependence. We study the predictability
of returns in the Chinese stock market by employing the wild bootstrap
automatic variance ratio test and the generalized spectral test. We find that
the return predictability vary over time and significant return predictability
is observed around market turmoils. Our findings are consistent with the
Adaptive Markets Hypothesis and have practical implications for market
participants.Comment: 11 Latex pages including 2 figures and 1 tabl
MEDIA DEVELOPMENT MODELS IN VIRTUAL WORLD
This paper studies three digital media development models in virtual world. We characterize the reve-nue mechanisms behind each model, by incorporating the concept of horizontal and vertical supply chain integration of digital media industry. We incorporate the core value of digital media develop-ment in the first model, which considers digital media as information goods. Pricing, quality differen-tiation, quantity discrimination, and content design combined determine the VW popularity and the financial performance. Based on the first model, the second model incorporates the advertising reve-nue. It becomes essential to optimize both information goods revenue and advertising revenue, while increasing one would decrease the other due to the traffic dynamics. Based on the first two models, the third model considers both vertical and horizontal supply chain integration in the digital media indus-try. In this model, we add one extra dimension of network externality that leads to better understand-ing of consumers, suppliers, and their mutual interest. Based on these three models, we suggest several strategic implications that facilitate operations, increase revenue, and enhance consumer experience, including strategic alliance, reduction of virtual-real world barriers, and tailored advertisement
Eulerian superpath approach to correct sequencing error in shotgun assembly
This work describes an error correction method based on the Euler Superpath problem. Sequence data is mapped to an Euler Superpath dynamically by Merging Transformation. With restriction and guiding rules, data consistency is maintained and error paths are separated from correct data: Error edges are mapped to the correct ones and after substitution (of error edges with right paths), corresponding errors in the sequencing data are eliminated.<br /
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