Ring Partition Research Articles

RESEARCH ON LIDAR SLAM METHOD WITH FUSED POINT CLOUD INTENSITY INFORMATION

Abstract. Under the current trend of intelligence and automation, simultaneous positioning and mapping technology has become one of the research hotspots. The main problems of SLAM technology research are to improve the robustness of mapping and positioning, establish an efficient back-end optimization system, and improve the generalization of SLAM technology. This paper proposes to fuse the intensity information of the point cloud and the geometric information of the environment scene to construct a globally consistent environment feature descriptor and use the non-iterative two-step method to perform the nearest neighbour search on the point cloud in the point cloud registration stage. Then use the globally consistent descriptor that has been constructed to extract the laser point cloud descriptor by using the ring partition method, combine the method based on domain search to search for the closest point cloud frame, and finally use Intensity-ICP to complete the loopback frame. Fine registration, outputs the optimal pose transformation, to complete the loop detection. We use our self-built mobile platform to verify the robustness and generalization of the improved laser SLAM algorithm in public datasets and campus datasets. Experimental results show that the improved algorithm reduces the trajectory drift of the mobile platform and improves the efficiency of point cloud registration and loop closure detection.

Content Authentication and Tampered Localization Using Ring Partition and CSLBP-Based Image Hashing

Content Authentication and Tampered Localization Using Ring Partition and CSLBP-Based Image Hashing

RTIM Hashing: Robust and Compact Video Hashing With a Rotation- and Translation-Invariant Model

Abstract Video hashing is a popular research topic in the fields of multimedia information and security because its fast matching and low-cost storage characteristics are widely used in many applications (video copy detection, video retrieval, video authentication, etc.). This paper describes a compact video hashing method with a rotation- and translation-invariant model (RTIM). The key contribution of this approach is that it innovatively reconstructs an input video into a 3D RTIM by combining ring partition and a pipeline histogram; this is a first in video hashing and helps make video hashes resistant to rotation and translation. Then, the proposed model is decomposed via Tucker decomposition, and the generated core tensor is used to produce a compact hash. As the core tensor is a compressed version of the original tensor, hash construction with the core tensor makes RTIM hashing compact and achieves desirable discrimination ability. Different from existing video hashing algorithms, RTIM hashing can not only resist many commonly used digital operations, especially video rotation and cyclic frame shifting, but also achieve good discrimination ability. Various experiments demonstrate the effectiveness of our algorithm. Receiver operating characteristic curve comparisons show that compared with the state-of-the-art video hashing algorithms, RTIM hashing is more robust and compact.

A Partition Spatial Filtering Method for Acoustic Array Configuration

Acoustic array is a ubiquitous tool for locating and quantifying sound sources. However, its effectiveness depends greatly on the array configuration. This paper presents an array configuration method to enhance array performance, especially on the spatial resolution and the Doppler effect correction. The problem of array configuration is formulated into a position matrix determined by introducing partition spatial filtering. Irregular coaxial ring grid spacings and partition filtering conditions are suggested to control array spatial resolution. Geometrical parameters and performance indicators are constructed to quantify the relationships between the array configuration and performance. Based on these quantitative relations, the spatial variation of the array beam pattern and the Doppler effect has got adaptive adjustment. In particular, an adaptive partition algorithm is proposed to reduce computation time. The performance of the method is examined numerically and experimentally, which is compared with the other methods. The results provide the method to guide the design of a 64‐microphone optimized array with high performance (1.8° spatial angle resolution and 40% Doppler frequency correction over the bandwidth from 800 Hz to 3000 Hz) and fast computing speed (18 s array generated time for 2000 arrays). Furthermore, an unusual feature of the method is that it can be utilized in the case when the source moves at a nonconstant velocity.

Robust Image Hashing with Low-Rank Representation and Ring Partition

Image hashing has attracted much attention of the community of multimedia security in the past years. It has been successfully used in social event detection, image authentication, copy detection, image quality assessment, and so on. This paper presents a novel image hashing with low-rank representation (LRR) and ring partition. The proposed hashing finds the saliency map by the spectral residual model and exploits it to construct the visual representation of the preprocessed image. Next, the proposed hashing calculates the low-rank recovery of the visual representation by LRR and extracts the rotation-invariant hash from the low-rank recovery by ring partition. Hash similarity is finally determined by L2 norm. Extensive experiments are done to validate effectiveness of the proposed hashing. The results demonstrate that the proposed hashing can reach a good balance between robustness and discrimination and is superior to some state-of-the-art hashing algorithms in terms of the area under the receiver operating characteristic curve.

Perceptual image hashing based on structural fractal features of image coding and ring partition

Perceptual image hashing finds increasing attention in several multimedia security applications. However, reaching the trade-off balance between the two most important properties of image hashing− robustness and discrimination, still remains the most restive challenge in hashing schemes. In this study, a robust image hashing technique is proposed by incorporating ring partition and fractal image coding. The scheme starts by normalizing the image to help in extracting its local features. Then the concept of ring partition is introduced in order to make our hash rotation invariant by dividing the image into 5 different rings to form a secondary image that possesses the invariant property. Further, image coding is introduced by extracting the structural fractal features to exploit dimensionality reduction and compression, hence, generating a robust hash. To ensure the system’s security, encryption is performed on the generated fractal elements before the final hash construction. We conduct series of experiments to evaluate the performance of our scheme. The achieved result shows that our scheme is robust against several content-preserving attacks such as image rotation, JPEG compression, gamma correction, gaussian low pass filtering, image scaling, cropping, brightness adjustment and contrast adjustment. In addition, the receiver operating characteristics is used to show the discriminative capability and robustness of our scheme as compared to other state-of-art schemes in the literature.

Robust image hashing via visual attention model and ring partition.

Robustness is an important property of image hashing. Most of the existing hashing algorithms do not reach good robustness against large-angle rotation. Aiming at this problem, we jointly exploit visual attention model and ring partition to design a novel image hashing, which can make good rotation robustness. In the proposed image hashing, a visual attention model called PFT (Phase spectrum of Fourier Transform) model is used to detect saliency map of preprocessed image. The LL sub-band of saliency map is then divided into concentric circles invariant to rotation by ring partition, and the means and variances of DWT coefficients on concentric circles are taken as image features. Next, these features are encrypted by a chaotic map and the Euclidean distances between normalized encrypted features are finally exploited to generate hash. Similarity between hashes is measured by L 1 norm. Many experimental tests show that our image hashing is robust to digital operations including rotation and reaches good discrimination. Comparisons demonstrate that classification performance of our image hashing outperforms those of some well-known hashing algorithms in terms of receiver operating characteristics curves. Simulation of image copy detection is carried out on an open image database called UCID and the result validates effectiveness of our hashing.

Robust image hashing through DWT-SVD and spectral residual method

In the last few decades, the discovery of various methods for generating secure image hash has become revolutionary in the field of image hashing. This paper presents an efficient approach to obtain image hash through DWT-SVD and a saliency detection technique using spectral residual model. The latest image hashing technique based on ring partition and invariant vector distance is rotation invariant for the large angle at the cost of being insensitive to corner forgery. But, due to the use of the central orientation information, the proposed system is rotation invariant for arbitrary angles along with sensitiveness to corner changes. In addition, we have used the HSV color space that gives desirable classification performance. It provides satisfactory results against large degree rotation, JPEG compression, brightness and contrast adjustment, watermarking, etc. This technique is also sensitive to malicious activities. Moreover, it locates the forged areas of a forged image. We have applied the proposed algorithm to a large collection of images from various databases. The receiver operating characteristics shows that the proposed method is better than some state-of-the-art methods.

Robust image hashing using ring partition-PGNMF and local features.

BackgroundImage authentication is one of the challenging research areas in the multimedia technology due to the availability of image editing tools. Image hash may be used for image authentication which should be invariant to perceptually similar image and sensitive to content changes. The challenging issue in image hashing is to design a system which simultaneously provides rotation robustness, desirable discrimination, sensitivity and localization of forged area with minimum hash length.MethodsIn this paper, a perceptually robust image hashing technique based on global and local features has been proposed. The Global feature was extracted using ring partition and projected gradient nonnegative matrix factorization (PGNMF). The ring partitioning technique converts a square image into a secondary image that makes the system rotation invariant. The PGNMF which is usually faster than the other NMFs has been used to reduce the dimension of the secondary image to generate the shorter hash sequence. The local features extracted from the salient regions of the image help to localize the forged region in the maliciously manipulated images. The image hashing techniques that use only global features are limited in discrimination.ResultsThe experimental results reveal that the proposed image hashing method based on global and local features provides better discrimination capability. The proposed hashing method is tested on large image sets collected from the different standard database. It is observed from the experimental results that the proposed system is robust to content-preserving operations and is capable of localizing the counterfeit area.ConclusionsThe combination of global and local features is robust against the content-preserving operations, which has a desirable discriminative capability. The proposed system may be used in image authentication, forensic evidence, and image retrieval, etc.

Robust Image Hashing With Ring Partition and Invariant Vector Distance

Robustness and discrimination are two of the most important objectives in image hashing. We incorporate ring partition and invariant vector distance to image hashing algorithm for enhancing rotation robustness and discriminative capability. As ring partition is unrelated to image rotation, the statistical features that are extracted from image rings in perceptually uniform color space, i.e., CIE L*a*b* color space, are rotation invariant and stable. In particular, the Euclidean distance between vectors of these perceptual features is invariant to commonly used digital operations to images (e.g., JPEG compression, gamma correction, and brightness/contrast adjustment), which helps in making image hash compact and discriminative. We conduct experiments to evaluate the efficiency with 250 color images, and demonstrate that the proposed hashing algorithm is robust at commonly used digital operations to images. In addition, with the receiver operating characteristics curve, we illustrate that our hashing is much better than the existing popular hashing algorithms at robustness and discrimination.

Molecular simulation of the concentration-dependent interaction of hydrophobic drugs with model cellular membranes.

We report here the interactions between a hydrophobic drug and a model cellular membrane at the molecular level using all-atom molecular dynamics simulations of paclitaxel, a hydrophobic cancer drug. The calculated free energy of a single drug across the bilayer interface displays a minimum in the outer hydrophobic zone of the membrane. The transfer free energy shows excellent agreement with reported experimental data. In two sets of long-time simulations of high concentrations of drug in the membrane (12 and 11 mol %), the drugs display substantial clustering and rotation with significant directional preference in their diffusion. The main taxane ring partitions in the outer hydrophobic zone, while the three phenyl rings prefer to be closer to the hydrophobic core of the membrane. The clustering of the drug molecules, order parameters of the lipid tails, and water penetration suggest that the fluidity and permeability of the membrane are affected by the concentration of drugs that it contains. Furthermore, at the high-concentration limit, the free energy minimum shifts closer to the hydrophobic core and the central barrier to cross the membrane decreases. Moreover, the transfer free energy change substantially increases, suggesting that increasing concentration facilitates drug partitioning into the membrane.

Robust Perceptual Image Hashing Based on Ring Partition and NMF

This paper designs an efficient image hashing with a ring partition and a nonnegative matrix factorization (NMF), which has both the rotation robustness and good discriminative capability. The key contribution is a novel construction of rotation-invariant secondary image, which is used for the first time in image hashing and helps to make image hash resistant to rotation. In addition, NMF coefficients are approximately linearly changed by content-preserving manipulations, so as to measure hash similarity with correlation coefficient. We conduct experiments for illustrating the efficiency with 346 images. Our experiments show that the proposed hashing is robust against content-preserving operations, such as image rotation, JPEG compression, watermark embedding, Gaussian low-pass filtering, gamma correction, brightness adjustment, contrast adjustment, and image scaling. Receiver operating characteristics (ROC) curve comparisons are also conducted with the state-of-the-art algorithms, and demonstrate that the proposed hashing is much better than all these algorithms in classification performances with respect to robustness and discrimination.

On superconformal characters and partition functions in three dimensions

Possible short and semishort positive energy, unitary representations of the Osp(2N|4) superconformal group in three dimensions are discussed. Corresponding character formulas are obtained, consistent with character formulas for the SO(3,2) conformal group, revealing long multiplet decomposition at unitarity bounds in a simple way. Limits, corresponding to reduction to various Osp(2N|4) subalgebras, are taken in the characters that isolate contributions from fewer states, at a given unitarity threshold, leading to considerably simpler formula. Via these limits, applied to partition functions, closed formula for the generating functions for numbers of BPS operators in the free field limit of superconformal U(n)×U(n) N=6 Chern–Simons theory and its supergravity dual are obtained in the large n limit. Partial counting of semishort operators is performed and consistency between operator counting for the free field and supergravity limits with long multiplet decomposition rules is explicitly demonstrated. Partition functions counting certain protected scalar primary semishort operators, and their superconformal descendants, are proposed and computed for large n. Certain chiral ring partition functions are discussed from a combinatorial perspective.

Explosion of solvent vapor in a ring partition of the floating roof

The relative importance of the vapor cloud explosion (VCE) hazard has grown in recent years. Many of large disasters were attributed to the VCE. This article introduced an explosion accident of solvent vapor in a ring partition of floating roof in detail. Source of explosive materials and ignition reason were analyzed, and the blast equivalency in ring partition was estimated in the specific conditions. The case would provide a reference for preventing the similar accident.

Ring signatures for benzenoids with up to seven rings, Part 1: Catacondensed systems

AbstractWe revisited the π‐electron ring partitions in catacondensed benzenoids and re‐examined structural regularities reported for the ring partitions in these compounds, seeking the origin of the observed regularities. We examined the distribution of the π‐electron ring partitions by counting the contributions arising from benzene rings having different assigned numbers of π‐electrons. This has led to a better insight into the underlying structure of the π‐electron ring partitions and also to a novel and unique π‐electron “signature” of individual rings in benzenoid hydrocarbons. The physical interpretation of the local π‐electron ring partition represents the local π‐electron density of benzenoid molecules, and is not an alternative index of local aromaticity as one may erroneously assume. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008

Ring signatures for benzenoids with up to seven rings, Part 2: Pericondensed systems

AbstractAn array of integers pij indicate in how many of the K resonance structures one finds 6 > i > 0 π‐electrons in the corresponding ring (which is labeled with capital letters A through a subsequent letter up to G). The index j for the rows indicates the ring type, denoted by capital letters (that is, j = 1 stands for A, j = 2 stands for B, etc.). Row sums lead to π‐electron ring partitions after division by the number K of resonance structures. Column sums lead to a sequence of seven integers (Ri sequence) which after division by K affords the ri sequence; this is finally converted into the signature of the benzenoid si sequence). The analysis of signatures for pericondensed benzenoids with h = 4 through 7 benzenoid rings has revealed interesting regularities and correlations with structure, and has also allowed a confirmation of Clar's theory by investigating five isomeric dibenzopyrenes. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008

Daunomycin Binding to Detergent Micelles: A Model System for Evaluating the Hydrophobic Contribution to Drug−DNA Interactions

The interaction of daunomycin with sodium dodecyl sulfate and Triton X-100 micelles was investigated as a model for the hydrophobic contribution to the free energy of DNA intercalation reactions. Measurements of visible absorbance, fluorescence lifetime, steady-state fluorescence emission intensity, and fluorescence anisotropy indicate that the anthraquinone ring partitions into the hydrophobic micelle interior. Fluorescence quenching experiments using both steady-state and lifetime measurements demonstrate reduced accessibility of daunomycin in sodium dodecyl sulfate micelles to the anionic quencher iodide and to the neutral quencher acrylamide. Quenching of daunomycin fluorescence by iodide in Triton X-100 micelles was similar to that seen with free daunomycin. Studies of the energetics of the interaction of daunomycin with micelles by fluorescence and absorbance titration methods and by isothermal titration calorimetry in the presence of excess micelles revealed that association with sodium dodecyl sulfate and Triton X-100 micelles is driven by a large negative enthalpy. Association of the drug with both types of micelles also has a favorable entropic contribution, which is larger in magnitude for Triton X-100 micelles than for sodium dodecyl sulfate micelles. The thermodynamic profile for the interaction of daunomycin with both types of micelles is characteristic of the "nonclassical" hydrophobic effect. The enthalpy for the interaction of daunomycin with sodium dodecyl sulfate micelles increases nonlinearly with temperature, indicating a positive (and temperature dependent) heat capacity change. The binding isotherm for daunomycin association with sodium dodecyl sulfate micelles was cooperative, with a Hill coefficient of 1.6. The cooperative behavior and the positive heat capacity change suggest that the drug alters micelle size or imposes order on the hydrocarbon interior of the micelle.

出口構造改良型遠心分離機による微粒子の分級

This study investigated the particle classification performance of an improved centrifugal separator. The improvements made in the centrifugal separator were the installation of another outlet near the wall of the conventional centrifugal separator and a ring partition in the outlet tube. As a result, it was found that 95% cut size of the centrifugal separator was lowered by reducing the ratio of fine particle's flow rate to the total flow rate because large fraction of coarse particles were collected into the outlet tube near the wall. The ring partition improved the particle classification performance because it prevented the mixing between fine and coarse particles. These experimental results were qualitatively in agreement with the predictions by the computational simulation.

A note on hair whorl position and cattle temperament in the auction ring

The objective of this study was to further describe the relationships between facial hair whorls and temperament in cattle. Cattle ( n=1636) from six commercial cattle auctions in Colorado and Texas were observed. Whorl location was classified according to lateral position (left, right, or middle) and height (high: above the top of the eye, middle: at eye level, low: below the bottom of the eye). A 4-point temperament score was used to rate each animal while it was in the auction ring. Cattle with a score of 1 remained calm and stood still or walked around, and those with a score of 4 were highly agitated and hit the ring fence, walls, partitions, or people with its head. The cattle observed were 75% Bos taurus beef breeds, 21% Holstein dairy cattle, 3% Bos indicus beef breeds, and 1% non-Holstein dairy breeds. Ten percent of cattle surveyed had no facial hair whorl, while 86% had a single spiral hair whorl, of which 47% had middle–middle whorl placement. Animals with a high whorl position or no hair whorl had higher temperament scores ( P=0.01). Cattle with low whorls were more likely to have greater lateral displacement of whorls off of the centerline than cattle with high or middle whorls ( P<0.01). Abnormally shaped whorls were more common on cattle with low whorls ( P<0.01) and on cattle with lateral whorls located off of the centerline ( P<0.01). Cattle with hair whorls on the centerline had more variable temperament scores ( P=0.04). Beef cattle had more abnormal whorls than Holsteins ( P<0.01). Temperament scores showed that Holsteins were calmer than beef cattle ( P<0.01). Facial hair whorls in cattle may be a useful management tool in assessing which animals may become disturbed in novel environments.

The relationship between reaction to sudden, intermittent movements and sounds and temperament.

Casual observations indicated that some cattle are more sensitive to sudden movement or intermittent sound than other cattle. Six commercial livestock auctions in two states and a total of 1,636 cattle were observed to assess the relationship between breed, sex, and temperament score on the response to sudden, intermittent visual and sound stimuli, such as the ringman swinging his arm for a bid and the sound of him briefly yelling a bid. A 4-point temperament score was used to score each animal while it was in the ring. The scores used were 1) walks and(or) stands still, with slow, smooth body movements; 2) continuously walks or trots, and vigilant; 3) gait is faster than a trot (runs even a couple of steps), with fast, abrupt, jerky movements, and very vigilant; and 4) hits the ring fence, walls, partitions, or people with its head. Animals were observed for flinches, startle responses, or orientation toward sudden, intermittent sounds, motions, and tactile stimulation, such as being touched with a cane or plastic paddle. The cattle observed were mostly Bos taurus beef breeds and Holstein dairy cattle. Holsteins were more sound-sensitive (P = .02) and touch-sensitive (P < .01) than beef cattle. Sensitivity to sudden, intermittent stimuli (e.g., sound, motion, and touch) increased as temperament score (excitability) increased. Cattle with a temperament score of 1 were the least sensitive to sudden, intermittent movement and sound and those with a temperament score of 4 were the most sensitive (P < .01). This same relationship was sometimes observed for touch but was not statistically significant. Motion-sensitive cattle were more likely than nonsensitive cattle to score a temperament rating of 3 or 4 (P < .01). Steers and heifers were more motion-sensitive than the older bulls and cows (P = .03). Beef cattle urinated (P < .01, n = 1,581) and defecated (P < .01, n = 1,582) more often in the ring than did dairy cattle. Cattle that became agitated during handling in an auction ring were the individuals that were most likely to be startled by sudden, intermittent sounds and movements. Reactivity to sudden, intermittent stimuli may be an indicator of an excitable temperament.