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Reversible Natural Language Watermarking Using Synonym Substitution and Arithmetic Coding
Get PDFFor protecting the copyright of a text and recovering its original content harmlessly, this paper proposes a novel reversible natural language watermarking method that combines arithmetic coding and synonym substitution operations. By analyzing relative frequencies of synonymous words, synonyms employed for carrying payload are quantized into an unbalanced and redundant binary sequence. The quantized binary sequence is compressed by adaptive binary arithmetic coding losslessly to provide a spare for accommodating additional data. Then, the compressed data appended with the watermark are embedded into the cover text via synonym substitutions in an invertible manner. On the receiver side, the watermark and compressed data can be extracted by decoding the values of synonyms in the watermarked text, as a result of which the original context can be perfectly recovered by decompressing the extracted compressed data and substituting the replaced synonyms with their original synonyms. Experimental results demonstrate that the proposed method can extract the watermark successfully and achieve a lossless recovery of the original text. Additionally, it achieves a high embedding capacity
Improved GNSS Cooperation Positioning Algorithm for Indoor Localization
Get PDFFor situations such as indoor and underground parking lots in which satellite signals are obstructed, GNSS cooperative positioning can be used to achieve high-precision positioning with the assistance of cooperative nodes. Here we study the cooperative positioning of two static nodes, node 1 is placed on the roof of the building and the satellite observation is ideal, node 2 is placed on the indoor windowsill where the occlusion situation is more serious, we mainly study how to locate node 2 with the assistance of node 1. Firstly, the two cooperative nodes are located with pseudo-range single point positioning, and the positioning performance of cooperative node is analyzed, therefore the information of pseudo-range and position of node 1 is obtained. Secondly, the distance between cooperative nodes is obtained by using the baseline method with double-difference carrier phase. Finally, the cooperative location algorithms are studied. The Extended Kalman Filtering (EKF), Unscented Kalman Filtering (UKF) and Particle Filtering (PF) are used to fuse the pseudo-range, ranging information and location information respectively. Due to the mutual influences among the cooperative nodes in cooperative positioning, the EKF, UKF and PF algorithms are improved by resetting the error covariance matrix of the cooperative nodes at each update time. Experimental results show that after being improved, the influence between the cooperative nodes becomes smaller, and the positioning performance of the nodes is better than before
A Proxy Re-Encryption with Keyword Search Scheme in Cloud Computing
Get PDFWith the widespread use of cloud computing technology, more and more users and enterprises decide to store their data in a cloud server by outsourcing. However, these huge amounts of data may contain personal privacy, business secrets and other sensitive information of the users and enterprises. Thus, at present, how to protect, retrieve, and legally use the sensitive information while preventing illegal accesses are security challenges of data storage in the cloud environment. A new proxy re-encryption with keyword search scheme is proposed in this paper in order to solve the problem of the low retrieval efficiency of the encrypted data in the cloud server. In this scheme, the user data are divided into files, file indexes and the keyword corresponding to the files, which are respectively encrypted to store. The improved scheme does not need to re-encrypt partial file cipher-text as in traditional schemes, but re-encrypt the cipher-text of keywords corresponding to the files. Therefore the scheme can improve the computational efficiency as well as resist chosen keyword attack. And the scheme is proven to be indistinguishable under Hash Diffie-Hellman assumption. Furthermore, the scheme does not need to use any secure channels, making it more effective in the cloud environment
A Highly Effective DPA Attack Method Based on Genetic Algorithm
Get PDFAs one of the typical method for side channel attack, DPA has become a serious trouble for the security of encryption algorithm implementation. The potential capability of DPA attack induces researchers making a lot of efforts in this area, which significantly improved the attack efficiency of DPA. However, most of these efforts were made based on the hypothesis that the gathered power consumption data from the target device were stable and low noise. If large deviation happens in part of the power consumption data sample, the efficiency of DPA attack will be reduced rapidly. In this work, a highly efficient method for DPA attack is proposed with the inspiration of genetic algorithm. Based on the designed fitness function, power consumption data that is stable and less noisy will be selected and the noisy ones will be eliminated. In this way, not only improves the robustness and efficiency of DPA attack, but also reduces the number of samples needed. With experiments on block cipher algorithms of DES and SM4, 10% and 12.5% of the number of power consumption curves have been reduced in average with the proposed DPAG algorithm compared to original DPA attack respectively. The high efficiency and correctness of the proposed algorithm and novel model are proved by experiments
Communication Mechanism and Algorithm of Composite Location Analysis of Emergency Communication based on Rail
Get PDFThe emergency communication system based on rail is an unconventional emergency communication mode, it is a complement equipment for that conventional communication system can’t work while tunnel mine accident occurs. Medium of transmission channel is the widely existing rail in the tunnel. In this paper we analyzed the characteristics of the rail transmission channel, verified the feasibility that information is transmitted by vibration signal in rail, we proposed the realization plan of the system. Communication protocol and processing mechanism suitable for rail transmission are designed according to the characteristics of channel bandwidth and low data transmission. Information communication with low bit rate and low bit error is realized in the communication simulation model. In the simplified model, we realized to transmit recognition speech information, and the error rate of the key text information is low to accept. The most concerned problem of personnel location in the mine disaster rescue is proposed, the composite algorithm is based on the model of signal amplitude attenuation, key node information and data frame transmission delay. Location information of hitting point can be achieved within the simplified model of the experiment. Furthermore, we discuss the characteristics of vibration signals passing through different channels
Some Geometric Invariants of Pseudo-Spherical Evolutes in the Hyperbolic 3-Space
Get PDFIn this paper, we study the pseudo-spherical evolutes of curves in three dimensional hyperbolic space. We use techniques from singularity theory to investigate the singularities of pseudo-spherical evolutes and establish some relationships between singularities of these curves and geometric invariants of curves under the action of the Lorentz group. Besides, we defray with illustration some computational examples in support our main results
Natural Language Semantic Construction Based on Cloud Database
Get PDFNatural language semantic construction improves natural language comprehension ability and analytical skills of the machine. It is the basis for realizing the information exchange in the intelligent cloud-computing environment. This paper proposes a natural language semantic construction method based on cloud database, mainly including two parts: natural language cloud database construction and natural language semantic construction. Natural Language cloud database is established on the CloudStack cloud-computing environment, which is composed by corpus, thesaurus, word vector library and ontology knowledge base. In this section, we concentrate on the pretreatment of corpus and the presentation of background knowledge ontology, and then put forward a TF-IDF and word vector distance based algorithm for duplicated webpages (TWDW). It raises the recognition efficiency of repeated web pages. The part of natural language semantic construction mainly introduces the dynamic process of semantic construction and proposes a mapping algorithm based on semantic similarity (MBSS), which is a bridge between Predicate-Argument (PA) structure and background knowledge ontology. Experiments show that compared with the relevant algorithms, the precision and recall of both algorithms we propose have been significantly improved. The work in this paper improves the understanding of natural language semantics, and provides effective data support for the natural language interaction function of the cloud service
A Novel Tube Lattice Slotted Core Highly Birefringent Photonic Crystal Fiber for THz Application
Get PDFA hexagonal slotted porous core tube lattice cladding photonic crystal fiber (SPC-TLC-PCF) is suggested to simultaneously achieve a very high birefringence and low transmission loss. At the operating frequency of 1 THz the proposed SPC-TLC-PCF yields a birefringence of 9.06×10−2 and effective material loss of 0.047 cm−1. The fiber operates at fundamental mode only and exhibits a small positive dispersion less than 1.6 ps/THz/cm over a band of 250 GHz (0.85 THz to 1.1 THz). Moreover, bending loss is around 1.61×10−7 cm−1 at 1 THz and confinement loss is also pretty small. These favorable attributes endorse this SPC-TLC-PCF much useful for polarization maintaining applications and sensing applications in THz regime
An Insight into Biomolecular Flexibility: Its Measuring, Modeling and Regulating on Function at Single Molecule Level
Get PDFThe protein structure-function paradigm implies that the structure of a protein defines its function. Crystallization techniques such as X-ray, electron microscopy (EM) and nuclear magnetic resonance (NMR) have been applied to resolve the crystal structure of numerous proteins, provided beautiful and informative models of proteins. However, proteins are not intrinsically in static state but in dynamic state, which is lack in crystal models. The protein flexibility, a key mechanical property of proteins, plays important roles in various biological processes, such as ligand-receptor interaction, signaling transduction, substrate recognition and post-translational modifications. Advanced time-resolved crystallography has been developed recent years to visualize and characterize the dynamic of proteins and reviewed in literatures. In the present review, we will focus on the single-molecule based techniques and theoretical methods in determining the flexibility of proteins, exhibit some interest examples of proteins and DNA molecular flexibility to their functions, and provide an insight in molecular flexibility from the biomechanics point of view
Non-Destructive Testing of Structures Using Optical and Other Methods: A Review
Get PDFNon-destructive testing (NDT) of structures is one of the most important tasks of the proper maintenance and diagnosis of machines and constructions structural condition. NDT methods contribute to the damage tolerance philosophy used in the aircraft design methodology as well as many other operation and maintenance programs of machinery and constructions. The following study is focusing on overviewing an important group of NDT methods: the optical and other ones, which found broad applicability in scientific and industrial studies nowadays. The paper discusses the selected most widely applicable methods, namely, visual testing, ultrasonic testing, radiographic testing, infrared thermography as well as electronic speckle pattern interferometry and shearographic testing. Besides the basic principles of testing using these methods, their potential applications in various industrial and technological branches are broadly discussed. The analysis as categorization of the NDT methods provided in this paper may help in selection of such methods in diagnosis of various types of structures and defects and damage occurring in these structures