Embedding Ratio Research Articles

Advanced eco-friendly and adsorptive membranes based on Sargassum dentifolium for heavy metals removal, recovery and reuse

Promising adsorptive mixed matrix membranes consisted of cellulose acetate (CA), as a polymer, and fine grinded Sargassum dentifolium (S) with different ratios, as adsorbent micro-particles, were prepared and investigated for Cd2+ and Zn2+ metal-ions removal. Different analytical techniques as Attentuated Total Reflectance Fourier Transform Infrared (ATR-FTIR), Scanning Electron Microscope (SEM) and Energy Dispersive X-ray microanalysis (EDX), porosity and swelling were performed for the prepared membranes. The morphological investigation showed well dispersion of the algal micro-particles and the high pore density of the mixed membrane compared to the blank one (CA only). The effect of different parameters that affecting the adsorption process as Sargassum dentifolium embedding ratio, pH, contact time and metal ions concentrations were optimized in order to get the highest removal efficiencies followed by full factorial design experiment. The adsorption results showed the maximum removal efficiencies of the CA-S membrane for 100 mg L−1 of both Cd2+ and Zn2+ were 95.9 and 82.79 % with dose 1.5 g L−1 and 2 g L−1, respectively. The adsorption isotherm, kinetics, and regeneration studies were displayed in order to determine the nature of the reaction and re-usability of the membrane. The adsorption process was related to Freundlich isotherm that describes the multilayer and heterogeneous adsorption of molecules to the adsorbent surface, and the pseudo first order kinetic was the most represent kinetic model for the adsorption process. Factorial experiments displayed that, time, pH and interaction between time and pH were the most significant factors in the adsorption process. This study proposed a new generation of adsorptive mixed matrix membranes based on the cellulose acetate and the algal micro-particles.

A novel energetic composite with a special sandwich microstructure: RDX/expanded graphite intercalation composite

In this paper, the RDX/expanded graphite (EG) intercalation composites were prepared by solvent/anti-solvent process to recrystallize RDX crystals into the holes, gaps and grooves of EG with controllable embedding ratio (maximum 87.0 wt%) and crystal size. RDX in the composites was in the most stableα-phase, which was benefit for its further application in the military industry. The stability and sensitivity of RDX were improved with higher melting and thermolysis temperature, activation enthalpy (ΔH ≠), critical temperature of thermal explosion (T b) and lower mechanical sensitivity. The advanced half-coated parallel multi-sandwiches microstructure of RDX/EG intercalation composites possessed two effects: (i) high heat conduction and (ii) hot spots isolation of the carbon microstructure, which were the key to higher performance.

Reversibly hiding data using dual images scheme based on EMD data hiding method

This paper presents a novel greyscale image reversible data hiding scheme based on exploiting modification direction (EMD) method. In this scheme, two 5-ary secret numbers are embedded into each pixel pair in the cover image according to the EMD method to generate two pairs of stego pixels. Two meaningful shadow images are obtained by shifting the generated corresponding pixel pairs, and the original image and the secret data can be accurately recovered when the two shadow images are operated together. Experimental results show that the proposed scheme has a good performance in the shadow image quality and the image embedding ratio.

Reversible Data Hiding in Encrypted Images Based on Reversible Integer Transformation and Quadtree-Based Partition

This paper presents an improved secure reversible data hiding scheme in encrypted images based on integer transformation, which does not need using a data hider key to protect the embedded secret data. We first segment the original image into blocks of various sizes based on the quadtree-based image partition. For each block, we reserve $m$ least significant bits (LSBs) of each pixel as embedding room based on the reversible integer transformation. In order to improve the security of the image encryption, we pad the $m$ LSBs of each pixel using the corresponding (8- $m$ ) most significant bits (MSBs) information after the transformation, which protects the security of the encryption key. Then, we encrypt the transformed image with a standard stream cipher. After the image encryption, the data hider embeds the secret data in the $m$ LSBs of the encrypted images through an exclusive or operation. On the receiving side, the receiver can extract the secret data after the image decryption and recover the original image without loss of quality. The security analysis shows that the proposed scheme improves the security weakness of the scheme directly using adaptive integer transformation. The experimental results show that the proposed method achieves a higher embedding ratio compared with several relevant methods.

An Adaptive Image Calibration Algorithm for Steganalysis

In this paper, a new adaptive calibration algorithm for image steganalysis is proposed. Steganography disturbs the dependence between neighboring pixels and decreases the neighborhood node degree. Firstly, we analyzed the effect of steganography on the neighborhood node degree of cover images. Then, the calibratable pixels are marked by the analysis of neighborhood node degree. Finally, the strong correlation calibration image is constructed by revising the calibratable pixels. Experimental results reveal that compared with secondary steganography the image calibration method significantly increased the detection accuracy for LSB matching steganography on low embedding ratio. The proposed method also has a better performance against spatial steganography.

Joint index coding and reversible data hiding methods for color image quantization

In this paper, we proposed two reversible data hiding methods for color image quantization based on lossless index coding. In index coding process, the indices are classified into three types: Type-1, Type-2, and Type-3 according to the relationship between the current index and its neighbors in lossless index coding. In the first method, Type-1 indices are taken to hide secret bits. To increase the hiding capacities, not only Type-1 indices but also Type-2 indices are used to embed secret bits in the second method. The experimental results show that the proposed methods achieve high hiding capacities while keeping acceptable compression bit rates. The required bit rates of the proposed methods are less than those of the uncompressed indices. The index table of each color quantized image can be recovered without any distortion after the hidden data has been extracted. Experimental results reveal that the first method is suitable for the applications that the required embedding ratio is less than or equal to 0.5 bit/index. For applications requiring a higher embedding ratio, the second method can be used to embed the secret data. The embedding ratio of the second method can be up to 0.98 bit/index.

Dual-image-based reversible data hiding scheme with integrity verification using exploiting modification direction

In this paper, a novel dual-image-based reversible data hiding scheme using exploiting modification direction (EMD) is proposed. This scheme embeds two 5-base secret digits into each pixel pair of the cover image simultaneously according to the EMD matrix to generate two stego-pixel pairs. By shifting these stego-pixel pairs to the appropriate locations in some cases, two meaningful shadows are produced. The secret data can be extracted accurately, and the cover image can be reconstructed completely in the data extraction and the image reconstruction procedure, respectively. Experimental results show that our scheme outperforms the comparative methods in terms of image quality and embedding ratio. Pixel-value differencing (PVD) histogram analysis reveals that our scheme achieves a higher security. Moreover, a tampered shadow can effectively be detected through the proposed scheme.

Ultrasonic-assisted fabrication and release kinetics of two model redox-responsive magnetic microcapsules for hydrophobic drug delivery

The smart biocompatible carriers have an advantage in the high-efficiency delivery and stimuli-responsive release of drugs. This study describes two model magnetic microcapsules (MMC) fabricated by sonicating the hydrophobic drug-loaded oil phase in an albumin aqueous solution, where magnetic nanoparticles are either encapsulated into the core or embedded onto the albumin shell. The as-prepared MMC with magnetic shell (MS) or with magnetic core (MC) shows an appropriate dispersibility with a well-defined spherical morphology in water, an excellent magnetism-mediated shifting ability for targeted drug delivery, and a good biocompatibility for high-level cell viability. Moreover, both the two microcapsules also show a high efficiency to trap the hydrophobic drugs, where the embedding ratios are 87.41% for MMC-MS and 95.31% for MMC-MC, respectively. Meanwhile in current study, the release kinetics and mechanism reveal that the sulfhydryl-crosslinked shell structure endows the MMC with a redox-responsive behavior to release the contents for controlled drug release, and the release rate or the release amount can be adjusted by changing the dosage of reducing agent. Therefore, the MMC have great potential as a smart carrier of hydrophobic drugs for enhancing the therapeutic efficiency.

An Effective Authentication Algorithm for Polygonal Models with High Embedding Capacity

Fragile watermarking algorithms for 3D models has attracted extensive research attention in recent years. Although many literatures have proposed lots of solutions on this issue, low embedding capacity and inaccurate located tampered region are still presented. Higher embedding capacity can reduce the probability of false alarms for authentication, while accurate tamper localization can detect all the modified vertices with fewer unaltered ones. This study proposes three strategies to enhance the embedding capacity and the detection accuracy of our previous algorithm. First, the modified message-digit substitution table can increase the embedding capacity by 11.5%. Second, the modified embedding ratio generation method can be integrated to raise the embedding capacity by about 47.74%. Finally, the strategy adopting a reduced number of reference vertices for authentication code generation accompanying the above two ones improves the embedding capacity up to 123.74%. Extensive experiments show that the proposed algorithm can achieve superior performance in terms of embedding capacity and tamper localization accuracy. Further, the model distortion between the original and the marked ones is small.

Fabrication of a Novel Beta Tricalcium Phosphate/Sodium Alginate/Poly(D,L-lactic acid) Composite Microsphere and Its Drug Releasing Property.

Bone repair microspheres have been widely studied due to their convenience during clinical operations. In this study, beta tricalcium phosphate/sodium alginate/poly(D,L-lactic acid) (β-TCP/SA/PDLLA) composite microspheres were successfully prepared using the liquid droplet method. Then, β-TCP/SA/PDLLA composite microspheres were soaked in simulated body fluids (SBF) for 7 days, and tested in an X-ray diffractometer (XRD). The results indicated that sodium alginate (SA) and poly(D,L-lactic acid) (PDLLA) are not limiting factors for the transformation of β-TCP to HA. Since sodium ions and bicarbonate ions were abundant, the final products were not pure HA but (Na, CO3)-substituted HA. When soaked in SBF, the structure of β-TCP/SA/PDLLA composite microspheres remained stable for at least 14 days suggesting that their anti-washout ability was suitable. Furthermore, the absence of calcination during the preparation of β-TCP/SA/PDLLA composite microspheres enabled the easy incorporation of vancomycin into the microspheres in situ at a final embedding ratio of 26.18%. Furthermore, the β-TCP/SA/PDLLA composite microspheres possessed excellent sustained drug release capability, and the release of vancomycin (92.8 wt.%) lasted for almost 168 h. Our results suggest that the β-TCP/SA/PDLLA composite microspheres could be used as a promising graft material particularly for bone repair.

Quantitative steganalysis of JPEG additive steganography based on boundary effect

For quantitative steganalysis of random additive steganography in JPEG DCT domain, an effective embedding ratio estimation method is proposed. First, the modification of coefficients after steganography is regarded as adding additive noise to coefficients. At the same time, variance of pixel differences on the boundary of spatial blocks is used to describe the boundary effect caused by coefficients changing. Then, the functional relationship between coefficient changing rate and boundary effect before and after embedding is presented by theoretical analysis. On the basis of that, the embedding ratio estimation equations are constructed for JPEG additive steganography. Specific forms of the estimation equations are different for various types of steganographies. Finally, for two types of typical DCT domain steganography JSteg and MB1, the corresponding embedding ratio estimation algorithms are presented. Experimental results show that the proposed embedding ratio estimation method based on boundary effect is effective for random additive steganography in JPEG DCT domain.

Controllable silver embedding into polypyrrole

Abstract Eccentric encapsulation of silver by polypyrrole was realized via the direct redox reaction between AgNO 3 and pyrrole in the presence of sodium dodecyl sulfate. A facile method based on the relative amount of the Ag embedded in the normalized PPy sphere was developed and utilized to compare the interface tension between Ag, PPy and the solution. Via the aid of the embedding ratio, the formation of the eccentric silver@polypyrrole (Ag@PPy) was investigated by a temporal process and tuning the surfactant concentration and reaction temperature. Furthermore, such a unique nanostructure allowed the manipulation on the Ag end to achieve mushroom-like Au/Ag-PPy via the galvanic replacement reaction between Ag and HAuCl 4 , which was also dependent on the embedding ratio. After generating the above later nanostructure, much more active sites were available and much better catalytic activity was achieved taking the reduction of 4-nitrophenol by NaBH 4 as an example reaction.

Text Steganography using Extensions Kashida based on the Moon and Sun Letters Concept

Existing steganography methods are still lacking in terms of capacity. Hence, a new steganography method for Arabic text is proposed. The method hides secret information bits within Arabic letters using two features, which are the moon and sun letters and the redundant Arabic extension character “-” known as Kashida. The Arabic alphabet contains 28 letters, which are classified into 14 sun letters and 14 moon letters. This classification is based on the way these letters affect the pronunciation of the definite article (ال) at the beginning of words. This method uses the sun letters with one extension to hold the secret bits ‘01’, the sun letters with two extensions to hold the secret bits ‘10’, the moon letters with one extension to hold the secret bits ‘00’ and the moon letters with two extensions to hold the secret bits ‘11’. The capacity performance of the proposed method is then compared to three popular text steganographic methods. Capacity is measured based on two factors which are Embedding Ratio (ER) and The Efficiency Ratio (TER). The results show that the Letter Points and Extensions Method produces 24.91% and 21.56% as the average embedding ratio and the average efficiency ratio correspondingly. For the Two Extensions ‘Kashida’ Character Method, the results for the average embedding ratio and the efficiency ratio are 56.76% and 41.81%. For the Text Using Kashida Variation Algorithm method, the average embedding ratio and the average efficiency ratio are 31.61% and 27.82% respectively. Meanwhile, the average embedding ratio and the efficiency ratio for the Proposed Method are 61.16% and 55.70%. Hence, it is concluded that the Proposed Method outweighs the other three methods in terms of their embedding ratio and efficiency ratio which leads to the conclusion that the Proposed Method could provide higher capacity than the other methods.

Segmentation Based Video Steganalysis to Detect Motion Vector Modification

This paper presents a steganalytic approach against video steganography which modifies motion vector (MV) in content adaptive manner. Current video steganalytic schemes extract features from fixed-length frames of the whole video and do not take advantage of the content diversity. Consequently, the effectiveness of the steganalytic feature is influenced by video content and the problem of cover source mismatch also affects the steganalytic performance. The goal of this paper is to propose a steganalytic method which can suppress the differences of statistical characteristics caused by video content. The given video is segmented to subsequences according to block’s motion in every frame. The steganalytic features extracted from each category of subsequences with close motion intensity are used to build one classifier. The final steganalytic result can be obtained by fusing the results of weighted classifiers. The experimental results have demonstrated that our method can effectively improve the performance of video steganalysis, especially for videos of low bitrate and low embedding ratio.

Adaptive Embedding Approach in Color Image Carrier for Covert Communication

Steganography plays a vital role in the field of covert communication. This paper proposes a novel embedding scheme which embeds secret data adaptively. The proposed scheme employs integer to integer Lifting Wavelet Transforms (LWT) and pixel strength to specify suitable locations for data embedding. The integer LWT eliminates distortions, which is produced because of rounding process in the convolutional wavelet transforms. The performance of the proposed scheme is addressed using image quality metrics based on Peak Signal To Noise Ratio (PSNR) versus embedding ratio. Moreover, Bit Error Rate (BER) is utilized to assess robustness of the scheme. The experimental results show that the proposed is superior over several embedding techniques such as embedding based convolutional wavelet transforms and Lest Significant Bits (LSBs). The range of PSNR is gained between 51.52 and 22.15dB for range of embedding rate between 5% and 35%. Furthermore, the technique results error free for retrieving of secret data. In addition to the above features, the proposed technique increases security level of embedded data due to adaptive embedding process that increases randomly of embedding locations. The proposed scheme can be used in several important applications such as bank tag for authentication, military communications. Also, it can be implemented easily as a hardware chip and combine with covert imaging systems.

Effects of Preparation Conditions on the Yield and Embedding Ratio of Vinyl Silicone Oil Microcapsules

Self-healing materials could repair themselves without external influences when they are damaged. In this paper, microcapsules are prepared by in-situ polymerization method with vinyl silicone oil as core material, polyurea formaldehyde (PUF) as wall material and polyvinyl alcohol as dispersants. The morphology and structure of the microcapsules are tested with scanning electron microscopy (SEM), polarizing microscope（PM）and laser particle analyzer(LPA). Effect of the reaction temperature, stirring speed and PVA concentration on the yield, embedding ratio, particle size and distribution of the microcapsules are studied. Results show that the microcapsules can be successfully prepared by in situ polymerization method. When the reaction temperature was 60℃, the stirring speed 1000 r/min, dispersant concentration 0.1%, the yield and embedding ratio of the microcapsule are 52.5% and 50.1%. The microcapsules prepared have smooth surface, well dispersibility, narrow particle size distribution and the average particle size is 13 μm.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.13026

열가소성 차선도장에서 반사유리알의 함침특성

Thermoplastic road markings are one of the most widely used road markings in the world. However, the durability of domestic road markings is relatively shorter than that of the global average of, approximately, three years. To overcome it, the conven- tional thermoplastic road markings were prepared by adding polyolefin and oxidized PE wax to conventional petroleum resin. In addition, the melting viscosity was designed below 500 cP at 220 ℃ as well as the optimum viscosity for spray painting, and embedding ratio of glass beads were controlled about 50∼60% by spraying in an interval of 1 second. Also the glass bead adhesive ratio was improved by reducing the amount of CaCO3 below 40 wt%. The retroreflectivity was tested under four different conditions to evaluate the abrasion resistance of thermoplastic road markings. The retroreflectivity coefficient sat- isfied the international standard (150 mcd⋅m -2 ⋅lux -1 ) in this study, and TPRM-7 was determined as an optimal ratio.

Reversible data hiding in encrypted images based on absolute mean difference of multiple neighboring pixels

Recently, with the development of cloud computing, more and more secret data are stored in cloud. Reversible data hiding in encrypted images is a technique that makes contribution to cloud data management in privacy preserving and data security. In previous works, Zhang and Hong presented two reversible dada hiding methods in encrypted images, respectively. However, Zhang’s work neglected the pixels in the borders of image blocks, and Hong et al.’s research only considered two adjacent pixels of each pixel. In addition, their works only considered that all image blocks are embedded into additional data. In this paper, we propose a novel method of evaluating the complexity of image blocks, which considers multiple neighboring pixels according to the locations of different pixels. Furthermore, data embedding ratio is considered. Experiments show that this novel method can reduce average extracted-bit error rate when the block size is appropriate.

Highly Luminescent Carbon‐Nanoparticle‐Based Materials: Factors Influencing Photoluminescence Quantum Yield

Unravelling the factors influencing photoluminescence (PL) quantum yield of the carbon nanoparticles (CNPs) is the prerequisite for preparing highly luminescent CNP‐based materials. In this work, an easy and effective method is reported for preparing highly luminescent CNP‐based materials. Water‐soluble luminescent CNPs (CNP‐Cs) with large size distribution (1–60 nm) with PL quantum yields of 22% are synthesized through a microwave pyrolysis approach. Energy transfer (ET) is confirmed to occur from small size CNPs (CNP‐Ss:1‐7 nm, blue emitters) to large size CNPs (CNP‐Ls:10–60 nm, green emitters). Further centrifugally separating CNP‐Cs resulted in an enhancement of the PL quantum yield up to 39% of CNP‐Ss aqueous solution. The PL quantum yield of CNP‐Ss could even be further improved in high‐viscosity solvents. PL quantum yield higher than 90% is achieved in films of commercial glue water embedded with the CNP‐Ss at embedding ratio lower than 3 wt%. By contrast, the yield is greatly decreased in the CNP‐C‐embedding films with embedding ratio higher than 1 wt%, which is due to self‐absorption, as well as enhanced ET between CNP‐Ss and CNP‐Ls. High‐viscosity solvents and polymer matrix are proposed to act as surface passivation reagents to enhance PL quantum yield of CNPs.

Reliable Detection of Histogram Shift-Based Steganography Using Payload Invariant Features

Reversible data hiding techniques can completely recover the cover images after extracting the secret message from the stego images and become a hot research topic recently. The histogram shift-based steganography, which is a kind of reversible data hiding technique, has good performance on imperceptibility. However, it also produces obvious features in the histograms of stego images. In this paper, we propose a steganalysis method based on the payload invariant features to detect the histogram shift-based steganography proposed by Ni et al. In the proposed steganalysis method, the minimum of the sum of the proposed features is first obtained, which is then compared with a predefined threshold to determine an image is a stego or a cover one. Experimental results show that the proposed steganalysis method can provide very high detection accuracy (about 98%) in various payload cases. Compared with the other steganalysis method, the proposed method can provide better detection performance under different embedding ratios and, therefore, is more reliable for detection of the histogram sift-based steganography.