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| Articles
by
Gang Luo |
Total Records (
4 ) for
Gang Luo |
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Gang Luo
,
Li Xie
,
Zhonghai Zou
,
Qi Zhou
and
Jing-Yuan Wang
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Fermentative hydrogen production from cassava stillage was conducted to investigate the influences of temperature (37 °C, 60 °C, 70 °C) and initial pH (4-10) in batch experiments. Although the seed sludge was mesophilic anaerobic sludge, maximum hydrogen yield (53.8 ml H2/gVS) was obtained under thermophilic condition (60 °C), 53.5% and 198% higher than the values under mesophilic (37 °C) and extreme-thermophilic (70 °C) conditions respectively. The difference was mainly due to the different VFA and ethanol distributions. Higher hydrogen production corresponded with higher ratios of butyrate/acetate and butyrate/propionate. Similar hydrogen yields of 66.3 and 67.8 ml H2/gVS were obtained at initial pH 5 and 6 respectively under thermophilic condition. The total amount of VFA and ethanol increased from 3536 to 7899 mg/l with the increase of initial pH from 4 to 10. Initial pH 6 was considered as the optimal pH due to its 19% higher total VFA and ethanol concentration than that of pH 5. Homoacetogenesis and methonogenesis were very dependent on the initial pH and temperature even when the inoculum was heat-pretreated. Moreover, a difference between measured and theoretical hydrogen was observed in this study, which could be attributed to homoacetogenesis, methanogenesis and the degradation of protein. |
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Gang Luo
,
Xingming Sun
and
Lingyun Xiang
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In this research, a steganographic algorithm based on
the directed Hamiltonian path selection in the complete digraph mapped
from multi-blogs with same article has been proposed. Firstly, we can
regard n different blogs referring to a same article as n different virtual
vertices and then connect them virtually to construct a complete digraph.
As there exist n! different directed Hamiltonian paths at most in a complete
digraph with n vertices, after numbering all directed Hamiltonian paths,
a large number converted from arbitrary secret information smaller than
n! can be expressed as a certain Hamiltonian path. In the process of the
actual realization, the cited links of the same article are used to indicate
the location of the former vertex of the current in a selected Hamiltonian
path. In the information-extracting process, we can recover the whole
Hamiltonian path by tracing the cited links and then decode this Hamiltonian
path to retrieve the hidden information. Based on the theoretical analysis
and the experimental proof, it demonstrates that the proposed steganography
has good imperceptibility and security. |
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Hui Peng
,
Gang Luo
and
Lingyun Xiang
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In this study, a new method that joint fingerprinting and
decryption at the client side is proposed for the electronic distribution of
text documents. In mass-scale electronic distribution systems fingerprint embedding
primarily at the server which may lead to computational load of server and bandwidth
burden. Fingerprinting at the client side will reduce the embedding complexity
and bandwidth usage but it is easy to pose a threat to security on the fingerprint
information and the protected content. It will be a challenge to design a client-side
embedding method which will not leak the embedding secrets or original content.
Some client-side embedding methods have been proposed for images, video and
other media which contain enough redundancy information and allow various processions.
But for text documents, to overcome this challenge will be more difficult. In
this study, by giving each user a personalized coding dictionary which constructed
based on synonym substitution, only one encoded and encrypted copy needs to
be sent by the server and fingerprint embedding is jointed with decryption at
the client side. Theoretical analysis and experimental results prove its practice. |
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Wang Li
,
Gang Luo
and
Lingyun Xiang
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In practical applications, in order to extract data from the
stego, some data hiding encryption methods need to identify themselves. When
performing data hiding, they embed some specific logo for self-identification.
However, it is unavoidable to bring themselves the risk of exposure. Suppose
each hidden method has a corresponding logo S and the attacker has a logo set
Φ which consists of some hidden methods’ logos. Once he find the logo S
which matches a logo in Φ, he can easily recognize the very method. To
solve this problem, we propose a method based on synchronization to hide the
specific sign or logo. First, the sender generates a key using a public variable
parameter which is always changing from time to time. Then, we can calculate
the hidden data’s location in the cover from the key. According to the locations,
we can embed the logo into the cover. As the public parameter is changing from
time to time, each transmission of hidden data has a unique location sequence.
When the stego reaches its receiver, according to the public parameter, the
receiver could generate the key and get the hidden data’s location to extract
the secret data correctly. Experimental results verify that the data hiding
method performs well and hardly has impacts on the cover’s quality and has little
impacts on the robustness, imperceptibility and capacity of the original stego-cover.
Besides, it is able to recover the key with linear time complexity when the
critical information which is used to generate the key is missing. |
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