22,317 research outputs found
Linear active disturbance rejection control of waste heat recovery systems with organic Rankine cycles
In this paper, a linear active disturbance rejection controller is proposed for a waste heat recovery system using an organic Rankine cycle process, whose model is obtained by applying the system identification technique. The disturbances imposed on the waste heat recovery system are estimated through an extended linear state observer and then compensated by a linear feedback control strategy. The proposed control strategy is applied to a 100 kW waste heat recovery system to handle the power demand variations of grid and process disturbances. The effectiveness of this controller is verified via a simulation study, and the results demonstrate that the proposed strategy can provide satisfactory tracking performance and disturbance rejection
Discovering Organizational Correlations from Twitter
Organizational relationships are usually very complex in real life. It is
difficult or impossible to directly measure such correlations among different
organizations, because important information is usually not publicly available
(e.g., the correlations of terrorist organizations). Nowadays, an increasing
amount of organizational information can be posted online by individuals and
spread instantly through Twitter. Such information can be crucial for detecting
organizational correlations. In this paper, we study the problem of discovering
correlations among organizations from Twitter. Mining organizational
correlations is a very challenging task due to the following reasons: a) Data
in Twitter occurs as large volumes of mixed information. The most relevant
information about organizations is often buried. Thus, the organizational
correlations can be scattered in multiple places, represented by different
forms; b) Making use of information from Twitter collectively and judiciously
is difficult because of the multiple representations of organizational
correlations that are extracted. In order to address these issues, we propose
multi-CG (multiple Correlation Graphs based model), an unsupervised framework
that can learn a consensus of correlations among organizations based on
multiple representations extracted from Twitter, which is more accurate and
robust than correlations based on a single representation. Empirical study
shows that the consensus graph extracted from Twitter can capture the
organizational correlations effectively.Comment: 11 pages, 4 figure
Study on the Relationship between Yogurt Packages, Drinking Methods and Residues and the Countermeasures
The aim of the study was to evaluate the relationship between different yogurt packages, drinking methods, and residues and the countermeasures. We chose 7 of the most common yogurt packages in the Chinese market, calculated the amount of residue left after yogurt consumption, compared the amount of yogurt residue left after using different methods of consumption from different types of packages, and conducted surveys in supermarkets, schools and other public places. After yogurt consumption, there are always residues left, and different packages and different drinking methods lead to different amounts of residues. The selection of yogurt package and the adoption of a good drinking method can clearly reduce the amount of residue. The solution that we suggest is to provide proper and clearly visible drinking instructions on the package to significantly reduce the amount of residue and wasted materials
Improving the security of multiparty quantum secret sharing against Trojan horse attack
We analyzed the security of the multiparty quantum secret sharing (MQSS)
protocol recently proposed by Zhang, Li and Man [Phys. Rev. A \textbf{71},
044301 (2005)] and found that this protocol is secure for any other
eavesdropper except for the agent Bob who prepares the quantum signals as he
can attack the quantum communication with a Trojan horse. That is, Bob replaces
the single-photon signal with a multi-photon one and the other agent Charlie
cannot find this cheating as she does not measure the photons before they runs
back from the boss Alice, which reveals that this MQSS protocol is not secure
for Bob. Finally, we present a possible improvement of the MQSS protocol
security with two single-photon measurements and six unitary operations.Comment: 4 pages, 2 figures; The revised version of the paper published in
Phys. Rev. A 72, 044302 (2005). A bug is modified and an addendum is adde
Properties of a coupled two species atom-heteronuclear molecule condensate
We study the coherent association of a two-species atomic condensate into a
condensate of heteronuclear diatomic molecules, using both a semiclassical
treatment and a quantum mechanical approach. The differences and connections
between the two approaches are examined. We show that, in this coupled
nonlinear atom-molecule system, the population difference between the two
atomic species plays a significant role in the ground-state stability
properties as well as in coherent population oscillation dynamics.Comment: 7 pages, 4 figure
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