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Chaotic systems perform well as a new rich source of cryptography and pseudo-random coding. Unfortunately their digital dynamical properties would degrade due to the finite computing precision. Proposed in this paper is a modified digital chaotic sequence generator based on chaotic logistic systems with a coupling structure where one chaotic subsystem generates perturbation signals to disturb the control parameter of the other one. The numerical simulations show that the length of chaotic orbits, the output distribution of chaotic system, and the security of chaotic sequences have been greatly improved. Moreover the chaotic sequence period can be extended at least by one order of magnitude longer than that of the uncoupled logistic system and the difficulty in decrypting increases 2128*2128 times indicating that the dynamical degradation of digital chaos is effectively improved. A field programmable gate array (FPGA) implementation of an algorithm is given and the corresponding experiment shows that the output speed of the generated chaotic sequences can reach 571.4 Mbps indicating that the designed generator can be applied to the real-time video image encryption.

STUDY DESIGN The possibility to prevent acute spinal cord injury (ASCI) by selective infliximab combined with methylprednisolone (MP) was assessed in experimental ASCI. OBJECTIVE To investigate the effects of infliximab, MP, and the combination of these 2 agents on expressions of NF-κB (nuclear factor Kappa B), TRADD (tumor necrosis factor receptor associated death domain), and FADD (fas associated death domain) in a rat model of acute spinal cord injury (ASCI), and to confirm the therapeutic efficacy and possible mechanism of infliximab combined with MP in the treatment of ASCI. SUMMARY OF BACKGROUND DATA The theory that SCI can induce tumor necrosis factor-α expression at the injury site has been evaluated. However, there are few data to confirm the therapeutic efficacy of infliximab combinated with MP in the treatment of rat SCI METHODS: One hundred eighty adult male Sprague Dawley rats with 280 to 300 g body weight were allocated randomly and accordingly. We applied Basso, Beattie, Bresnahan locomotor rating scale to assess the hindlimb motor functional score (10 rats × 6 groups), the hematoxylin and eosin stain and immunohistochemistry stain (10 rats × 6 groups) to assay the morphological changes of spinal cord, the arrangement and expressions of NF-κB, TRADD and FADD, and the RT-PCR (10 rats × 6 groups) to evaluate the messenger RNA expressions of NF-κB, TRADD, and FADD. RESULTS The results showed that both infliximab and MP could lower the expressions of NF-κB, TRADD, and FADD 24 hours after the ASCI, and increased Basso, Beattie, Bresnahan score on the 14th and the 21st days after ASCI, suggesting possible neuroprotective effectiveness on attenuating the severity of neurological deficits and improving the locomotor function in the rat ASCI model. Moreover, infliximab combined with MP exhibited the more powerful ability to this amelioration. CONCLUSION Infliximab combined with methylprednisolone may be an effective treatment for the recovery of ASCI. Further study is needed to determine if this neuroprotective effect is seen for long-term outcomes especially in human ASCI.

The strategy of storage and organization can be adjusted utilizing the access and distribution law of the spatial data, which will significantly improve system performance of spatial data services. The access and distribution law of the spatial data based on Hotmap and Zipf-like are statics, and can not reflect its global information real-time. A dynamic statistical method based on collaborative cloud is proposed in this paper to resolve above-mentioned problems. The nodes service capabilities are calculated in our algorithm. The node agents with good service capabilities are chosen preferentially in the group to fuse dynamic statistical information. The experimental results show that the performance of our algorithm can be improved by about 29% compared with the algorithm of random nodes. The algorithm can meet the need of dynamic statistics in large scale cloud mode with high efficiency.

Nowadays, a number of forensic algorithms have been developed to detect the manipulations of digital images. However, little consideration has been given to anti-forensic schemes capable of fooling the forensic methods. Aiming at this situation, a novel anti-forensic algorithm is proposed to counter a forensic analysis that can detect double JPEG compression with the same quantization matrix, and the limitation of existing image forensics are illustrated accordingly. The proposed algorithm allows generating tampered images without overall recompression, therefore eliminates the double quantization artifacts which will generally exist in tampered JPEG images. Experiment results show that the tampered images generated by the presented method not only have a good disguise effect, but can also effectively counter the forgery detection method that is based on the detection of double JPEG compression with the same quantization matrix.

In the object-based storage architecture of spatial data, accesses to metadata are 50% to 80% of the total data accesses, so metadata management and partitioning are very important. However, many typical and traditional methods for metadata partitioning, such as directory subtree partitioning, hashing partitioning, etc., should face the issues of hotspot and load balancing. In this paper, we analyzed the accesses to spatial data that follows Zipf-like distribution and has locality of reference, and proposed a dynamic method for metadata partitioning based on intensive access pattern of spatial data. This method considered the temporal locality and spatial locality of accesses to tile, put forward tile access rank algorithm based on the sum of access times per interval time, and got tile access probability by Zipf-like's law for dynamic hashing partitioning of metadata. The experiment results presented the improving of efficiency in tile access rank, and showed that the method for metadata partitioning is an effective solution for hotspot and load balancing issues.

An active-passive security protection method for remote sensing image is proposed in the paper. High strength content encryption method is used to protect the security of remote sensing image in the process of storage and transmission. The encryption side only need to encrypt the image once, users can get different fingerprinting image by decrypting the image with different keys. If user leaks the decrypted image, they will be identified by embedded fingerprinting information. Considering the remote sensing image's special requirements to embed fingerprinting, a way to control the strength of embedded fingerprinting is proposed to reduce the influence to the application of remote sensing image.

H + -implantation in LiNbO 3 induces radiation damage, lattice disorder and corresponding refractive index changes. The refractive index decreases in the nuclear stopping region at the end of the implanted ion's track, but changes very little in the electronic stopping region. Thus, these characteristics can be used for fabrication of planar waveguides. The waveguide fabrication process comprises a furnace annealing in flowing oxygen to remove the damage and optical absorption from the guiding layer as well as to compensate oxygen loss during ion implantation. The damaged buried layer together with electronic excitement forms an optical “well”, which confines optical mode propagation. The results of this work show that H + -implantation can be a promising technique for fabrication of low-loss waveguides.