Contour Shape Research Articles

The structure and prevalence of superficial carious and non-carious lesions of permanent and deciduous enamel in children who presented for routine dental care in various districts of St. Petersburg

Relevance. To increase the effectiveness of prevention and treatment protocols, it is above all necessary to consider the activity of caries, especially at the early enamel lesion stage, in the form of a white spot, to make the correct diagnosis based on a clinical examination, which assesses the location, change in surface hardness, symmetry, contour shape, depth, color and opacity of the lesion. Different causes of superficial enamel discoloration, in the form of white spots, are paramount for the restorative treatment as the quality of the enamel preparation affects the marginal fit and the durability of the restoration. However, poor oral hygiene, disturbance in eating behavior affect the course of non-carious hard-tissue diseases, which caries may complicate. Purpose – to optimize the diagnosis of initial dental enamel lesions to improve the caries prevention quality.Materials and methods. The study examined 460 children living in the Central and Krasnoselsky districts of St. Petersburg. The following indices assessed hard tissue condition: OHI-S, Greene and Vermillion; OHI by O'Leary T., Drake R., Naylor; White spot lesions index, Gorelick L, Geiger A. M, Gwinnett A. J., DMFT and df; caries activity.Results. The total prevalence of superficial (initial) lesions of hard tissues was 37.82%, i.e. 174 people out of 460 examined patients had superficial enamel lesions according to the criteria of I and II categories. The study found enamel changes in the age groups: 5-6 years (130) – 36 people (27.69%); 12 years old (175) – 62 people (35.42%); 15 years old (155) – 76 people (49.03%).Conclusions. Focusing on the caries activity signs rather than a precise differential diagnosis of the lesion nature is necessary to provide well-timed treatment and prevention upon detecting initial enamel lesion at a dental check-up.

Three-Dimensional Reconstruction of Cerebrovascular and Algorithm Realization.

Objective In the three-dimensional reconstruction of CT cerebrovascular medical image registration, a new optimization algorithm based on the relative position information between the contours of various blood vessels in the image is proposed. Methods Using the rule that the center of gravity of the vascular tissue structure on the series of slices has continuity, find the registration relationship between the contours of the vessels in the two adjacent slices. Because the shape of cerebrovascular contour is relatively symmetrical, its center of gravity is slightly away from its geometric center. Therefore, the geometric center is used to replace the center of gravity, and the “mass” of each contour is calculated according to the area of each contour to achieve the registration of the blood vessel contour. Results The method has the characteristics of global optimization and stronger robustness. Conclusion The cerebrovascular image obtained by this method is more realistic and can be used for the import of various software, simulation training, and later research, which provides an effective method for preoperative simulation of cerebrovascular intervention surgery.

Automatic coarse registration of point clouds using plane contour shape descriptor and topological graph voting

Registration is a basic yet crucial task in point cloud processing. Obtaining robust as well as accurate features and correspondences is critical to feature-based point cloud registration. Aiming at structured urban scenes, this paper employs plane as primitive for feature extraction and proposes an automatic coarse registration algorithm of pairwise point clouds based on plane contour shape descriptor and topological graph voting. It contains three major steps: First, in order to improve the efficiency and accuracy of plane extraction, an efficient voxel-based plane segmentation algorithm is applied, then a RANSAC plane fitting method is used to obtain high precision plane parameters. Second, we propose a plane contour shape descriptor, hole inner angle combined with triangular centroid distance (HIA-TCD), for obtaining corresponding planes in two laser scans, which is robust to the contour shape matching in the urban scene. Finally, according to the position relationship between plane correspondences, a topological graph is built, and an edge voting strategy is proposed to eliminate potential unreliable plane correspondences, then the optimal matched planes are selected to estimate the rigid transformation. The algorithm is tested by three sets of large-scale outdoor and two sets of indoor scene data, and the experimental results show that the presented algorithm can effectively register the pairwise point cloud. In the outdoor scene, the rotation errors are less than 0.3°, and the translation errors are less than 0.1 m. In the indoor scene, the rotation errors are less than 0.2°, and the translation errors are less than 0.1 m. In addition, our algorithm is superior to the state-of-the-art in efficiency.

Acoustic structure and information content of trumpets in female Asian elephants (Elephas maximus).

Most studies on elephant vocal communication have focused on the low-frequency rumble, with less effort on other vocalization types such as the most characteristic elephant call, the trumpet. Yet, a better and more complete understanding of the elephant vocal system requires investigating other vocalization types and their functioning in more detail as well. We recorded adult female Asian elephants (Elephas maximus) at a private facility in Nepal and analyzed 206 trumpets from six individuals regarding their frequency, temporal and contour shape, and related acoustic parameters of the fundamental frequency. We also tested for information content regarding individuality and context. Finally, we recorded the occurrence of non-linear phenomena such as bifurcation, biphonation, subharmonics and deterministic chaos. We documented a mean fundamental frequency ± SD of 474 ± 70 Hz and a mean duration ± SD of 1.38 ± 1.46 s (Nindiv. = 6, Ncalls = 206). Our study reveals that the contour of the fundamental frequency of trumpets encodes information about individuality, but we found no evidence for trumpet subtypes in greeting versus disturbance contexts. Non-linear phenomena prevailed and varied in abundance among individuals, suggesting that irregularities in trumpets might enhance the potential for individual recognition. We propose that trumpets in adult female Asian elephants serve to convey an individual’s identity as well as to signal arousal and excitement to conspecifics.

A novel complementation method of an acoustic shadow region utilizing a convolutional neural network for ultrasound-guided therapy.

Noise-free ultrasound images are essential for organ monitoring during regional ultrasound-guided therapy. When the affected area is located under the ribs, however, acoustic shadow is caused by the reflection of sound from hard tissues such as bone, and the image is output with missing information in this region. Therefore, in the present study, we attempt to complement the image in the missing area. The overall flow of the complementation method to generate a shadow-free composite image is as follows. First, we constructed a binary classification method for the presence or absence of acoustic shadow on a phantom kidney based on a convolutional neural network. Second, we created a composite shadow-free image by searching for a suitable image from a time-series database and superimposing the corresponding area without shadow onto the missing area of the target image. In addition, we constructed and verified an automatic kidney mask generation method utilizing U-Net. The complementation accuracy for kidney tracking could be enhanced by template matching. Zero-mean normalized cross-correlation (ZNCC) values after complementation were higher than that of before complementation under four different data generation conditions: (i) changing the position of the bed of the robotic ultrasound diagnostic system in the translational direction, (ii) changing the probe angle in the translational direction, (iii) with the addition of rotational motion of the probe to condition (ii). Although there was large variation in the shape of the kidney contour in condition (iii), the proposed method improved the ZNCC value from 0.5437 to 0.5807. The effectiveness of the proposed method was demonstrated in phantom experiments. Verification of its effectiveness in real organs is necessary in future study.

Mathematical Modeling for Ceramic Shape 3D Image Based on Deep Learning Algorithm

Ceramic image shape 3D image modeling focuses on of ceramic that was obtained from the camera imaging equipment such as 2D images, by normalization, gray, filtering denoising, wavelet image sharpening edge enhancement, binarization, and shape contour extraction pretreatment processes such as extraction ceramic image shape edge profile, again, according to the image edge extraction and elliptic rotator ceramics phenomenon. The image distortion effect was optimized by self-application, and then the deep learning modeler was used to model the side edge contour. Finally, the 3D ceramic model of the rotating body was restored according to the intersection and central axis of the extracted contour. By studying the existing segmentation methods based on deep learning, the automatic segmentation of target ceramic image and the effect of target edge refinement and optimization are realized. After extracting and separating the target ceramics from the image, we processed the foreground image of the target into a three-dimensional model. In order to reduce the complexity of the model, a 3D contextual sequencing model is adopted to encode the hidden space features along the channel dimensions, to extract the causal correlation between channels. Each module in the compression framework is optimized by a rate-distortion loss function. The experimental results show that the proposed 3D image modeling method has significant advantages in compression performance compared with the optimal 2D 3D image modeling method based on deep learning, and the experimental results show that the performance of the proposed method is superior to JP3D and HEVC methods, especially at low bit rate points.

Prediction of discharge coefficients for broad-crested weirs using expert systems

ABSTRACT Broad crested weirs can be used to make discharge measurements in irrigation canals; the entrance of stepped weirs or chutes are sometimes designed as a broad crested weir structure. These structures are also sometimes used for the dam body. In this study, the Artificial Neural Network (ANN) and M5 model tree methods are used to predict discharge coefficients (Cd ) for broad crested weirs. The results from these two models are compared with nonlinear regression equations. Four series of data obtained from different rectangular broad crested weirs have been used and important dimensionless parameters have been defined. Results show that the ANN procedure is superior to the M5 model and regression approaches. The accuracy for ANN is quantified by R = 0.966 and RMSE = 0.038. All the three methods are able to provide a reasonable prediction for Cd ; the M5 model tree provides four linear equations that can be used to estimate Cd . The shape of the Cd contours shows that the effect of weir height (P) exceeds that of the weir length (L).

Influence of particle mineralogy and size on the morphological characteristics of mineral fillers

The morphological characteristics of mineral filler particles, such as contour shape, angularity and surface texture, are closely related to their mineralogy and size and the crushing process used. In the present study, the importance and effects of particle mineralogy and size on the morphology of different mineral fillers were examined. A total of 12 mineral filler fractions were prepared using the same grinding process and sieving method, and analyzed by digital imaging. Six parameters were used to describe the 2-dimensional characteristics of mineral filler particles based on digital image processing. The sensitivity of these parameters was analyzed by correlation and analysis of variance methods. The results show that for mineral fillers of the same particle mineralogy, as the particle size decreases, the contour shape becomes more regular and the angularity and surface texture becomes less abundant. For mineral fillers of the same particle size, the granite filler particles have a more regular contour shape and richer angularity and surface texture than the limestone and basalt filler particles. The form factor, angularity parameter AI1 and fractal dimension can best reflect the sensitivity of contour shape, angularity and surface texture characteristics of mineral filler particles to particle mineralogy and size.

A comparison of transient killer whale (Orcinus orca) whistles in Alaska

Several species of dolphins in both isolated and continuous regions exhibit geographic variation in whistles. Although whistles are thought to be learned, possible structural components are exhibited across communities. Whistles from three transient killer whale (Orcinus Orca) groups, Prince William Sound, the Pribilof Islands, and False Pass were compared for spectral and temporal properties. Of 395 randomly selected frequency contours of whistles, there were 32 shape categories of whistles. Overall, whistle shapes from different areas reflect homogeneity, with four whistle shapes comprising 50% of all repertoires. The most common whistle contour shapes were up, down, flat, and oscillatory. Whistles from at St. Paul Island, described here for the first time, had higher fundamental frequencies and shorter durations than whistles from Prince William Sound and False Pass. Surface whistles from St. Paul Island had higher mean frequencies than those recorded at depth with passive acoustics. One identical whistle type was found at both St. Paul Island and False Pass, which suggests the same whales travel between the two areas. The longest whistles and most variable whistles were recorded at False Pass.

Contour- and Texture-based analysis for victim identification in forensic odontology

PurposeForensic dentistry is the application of dentistry in legal proceedings that arise from any facts relating to teeth. The ultimate goal of forensic odontology is to identify the individual when there are no other means of identification such as fingerprint, Deoxyribonucleic acid (DNA), iris, hand print and leg print. The purpose of selecting dental record is for the teeth to be able to withstand decomposition, heat degradation up to 1600 °C. Dental patterns are unique for every individual. This work aims to analyze the contour shape extraction and texture feature extraction of both radiographic and photographic dental images for person identification.Design/methodology/approachTo achieve an accurate identification of individuals, the missing tooth in the radiograph has to be identified before matching of ante-mortem (AM) and post-mortem (PM) radiographs. To identify whether the missing tooth is a molar or premolar, each tooth in the given radiograph has to be classified using a k-nearest neighbor (k-NN) classifier; then, it is matched with the universal tooth numbering system. In order to make exact person identification, this research work is mainly concentrate on contour shape extraction and texture feature extraction for person identification. This work aims to analyze the contour shape extraction and texture feature extraction of both radiographic and photographic images for individual identification. Then, shape matching of AM and PM images is performed by similarity and distance metric for accurate person identification.FindingsThe experimental results are analyzed for shape and feature extraction of both radiographic and photographic dental images. From this analysis, it is proved that the higher hit rate performance is observed for the active contour shape extraction model, and it is well suited for forensic odontologists to identify a person in mass disaster situations.Research limitations/implicationsForensic odontology is a branch of human identification that uses dental evidence to identify the victims. In mass disaster circumstances, contours and dental patterns are very useful to extract the shape in individual identification.Originality/valueThe experimental results are analyzed both the contour shape extraction and texture feature extraction of both radiographic and photographic images. From this analysis, it is proved that the higher hit rate performance is observed for the active contour shape extraction model and it is well suited for forensic odontologists to identify a person in mass disaster situations. The findings provide theoretical and practical implications for individual identification of both radiographic and photographic images with a view to accurate identification of the person.

Detection of Sickle Cell Anemia Through Contour Evidence Extraction and Estimation

Diagnosis of sickle cell anemia by manual visual inspection through microscope is time consuming and causes human errors. Observational errors occur mostly due to overlapping of cells in blood smear image. Here, an automatic segmentation approach is introduced which isolates sickle cells from all other cells within a blood sample. The proposed system is an approach to find the elliptically shaped sickle cells through geometric feature extraction and contour based segmentation to isolate sickle cells. This technique is a method of isolating sickle cells from other cells within blood sample using cell morphology. A combined approach of extraction of seed points, contour extraction and estimation of contours is used for separation of sickle cells from red blood cells. The methods used for the extraction of seed points are by Ultimate Erosion for Convex Sets and Fast Radial Symmetry transform. The contour evidence is extracted by associating edges of the cells to the seed points. The overlapping and clustered cells in image are identified using ellipse fitting method for contour estimation. Using the seed points and the contour extraction, the edges of the cells are estimated. The lines joining the shape of cells are drawn through estimation of shape of contour. This eliminates cells other than elliptical shaped cells. The proposed system can successfully isolate sickle cells from healthy blood cells within the blood smear image. This automated system has a better accuracy and faster computation speed compared to the existing methods for the detection of sickle cells. This identification methodology helps the health professionals for faster diagnosis.

Computational Model of Outer Circle and Inner Ellipse Shield Tunnel Lining Structure

Subway tunnels are mostly located in strata with an uneven pressure. This uneven pressure is usually manifested by lateral pressure coefficients less than 1. To adapt to the unevenness of the stratum load, in this study, we propose a new shield tunnel lining structure—outer circle and inner ellipse shield tunnel lining structure—whose outer contour remains circular and the inner contour shape of the structure is designed according to the load conditions. We used the stiffness step discounting method to obtain the calculation coefficients used in the force method formulas and established the calculation model of the outer circle and inner ellipse shield tunnel linings. The force method was then used to determine the force distribution characteristics of the outer circle and inner ellipse shield tunnel lining structure. During the verification, it was sufficient to analyze whether the waist structure rigidity met the safety conditions. This simplifies the design elements. The internal space area of our proposed design is expanded by 0.86 m2 compared to the internal space area of the equal stiffness shield tunnel lining design.

New computational results for a prototype of an excitable system

This present paper uses a well known computational scheme such as the modified (G'/G)-expansion method to the nonlinear predator–prey (NPP) system for forming new computational results that define a prototype of an excitable system. We construct twenty new computational solutions that define hyperbolic, trigonometric, and rational. Two-dimensional, three-dimensional, and contour shapes are depicted to demonstrate the acquired answers' more physical as well as dynamical features. Comparing our acquired responses and that obtained in previously written research articles presents the novelty of our research. The computational scheme's representation demonstrates its helpful and straightforward procedure that produces a kink-type shape, singular kink shape, bright and dark singular lump shape, multiple bright and dark lump shape, and different types of singular kink shapes. Their ability to manipulate many applications of nonlinear partial differential equations (NLPDEs) is also presented.

Constant curvature segments as building blocks of 2D shape representation.

How the visual system represents shape, and how shape representations might be computed by neural mechanisms, are fundamental and unanswered questions. Here, we investigated the hypothesis that 2-dimensional (2D) contour shapes are encoded structurally, as sets of connected constant curvature segments. We report 3 experiments investigating constant curvature segments as fundamental units of contour shape representations in human perception. Our results showed better performance in a path detection paradigm for constant curvature targets, as compared with locally matched targets that lacked this global regularity (Experiment 1), and that participants can learn to segment contours into constant curvature parts with different curvature values, but not into similarly different parts with linearly increasing curvatures (Experiment 2). We propose a neurally plausible model of contour shape representation based on constant curvature, built from oriented units known to exist in early cortical areas, and we confirmed the model's prediction that changes to the angular extent of a segment will be easier to detect than changes to relative curvature (Experiment 3). Together, these findings suggest the human visual system is specially adapted to detect and encode regions of constant curvature and support the notion that constant curvature segments are the building blocks from which abstract contour shape representations are composed. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Research on Individualized Phantom Based on 3D Printing for Radiotherapy Dose Verification

Dose verification is carried out on the individualized three-dimensional phantom based on 3D printing technology, which simulates the anatomical structure of human body, contour shape, tumor anatomical structure and other dangerous organs to the greatest extent, and produces a reasonable and effective dose validation phantom. According to the need to obtain effective patient data, import Mimics software to reconstruct the parts of the body and its surrounding tissues and organs that need to be measured, and make them into three-dimensional shell components. The 3D printing is used to assemble and fill the equivalent tissue, and then the body phantom is made. The phantom was scanned by CT and the data was transmitted to TPS system. The previously completed treatment plan was transplanted to the phantom. The phantom was placed according to the patient's location information, irradiated and measured data. The three-dimensional shell assembly is completely reconstructed according to the patient's data, and the contour difference is not significant. The shell is filled with tissue radiation equivalent material whose CT value is the same as the average CT value of the shell volume. The CT image data show that the radiation equivalence of the phantom is similar to the actual tissue of the patient, and the equivalent dose distribution conforms to the conventional treatment range. It can provide a reliable means of dose verification for the accurate design of intensity modulated radiation therapy.

Wetting of Dehydrated Hydrophilic Pseudomonas fluorescens Biofilms under the Action of External Body Forces.

Wetting of dehydrated Pseudomonas fluorescens biofilms grown on glass substrates by an external liquid is employed as a means to investigate the complex morphology of these biofilms along with their capability to interact with external fluids. The porous structure left behind after dehydration induces interesting droplet spreading on the external surface and imbibition into pores upon wetting. Static contact angles and volume loss by imbibition measured right upon droplet deposition indicate that biofilms of higher incubation times show a higher porosity and effective hydrophilicity. Furthermore, during subsequent rotation tests, using Kerberos device, these properties dictate a peculiar forced wetting/spreading behavior. As rotation speed increases a long liquid tail forms progressively at the rear part of the droplet, which stays pinned at all times, while only the front part of the droplet depins and spreads. Interestingly, the experimentally determined retention force for the onset of droplet sliding on biofilm external surface is lower than that on pure glass. An effort is made to describe such complex forced wetting phenomena by presenting apparent contact angles, droplet length, droplet shape contours, and edges position as obtained from detailed image analysis.

Proposing stratified segmented finite line source (SS-FLS) method for dynamic simulation of medium-deep coaxial borehole heat exchanger in multiple ground layers

Extracting thermal energy from medium-deep ground layer for building heating is a promising means for pushing forward cleaner heating initiative. There is no available analytical model that can provide fast, accurate and effective simulation of both fluid and soil temperature field of deep borehole heat exchanger (DBHE) under complex geothermal gradient and subsurface stratifications. In this study, a stratified segmented finite line source method (SS-FLS) is proposed as an main contribution and novelty. The proposed model is validated by comparing with finite element method, model degradation example, and actual engineering project data of DBHE. The accuracy and robustness of the SS-FLS is fully checked. Then the effects of stratification on soil temperature field and fluid temperature field are investigated. It is found that the shape of temperature contour and temperature distribution have direct link with stratification as well as heat extraction rate on the heat pump side. Moreover, two critical model parameters are discussed in details which poses an important guide for both model application and system analysis.

Dynamical Green’s function for elastic half-space, and energy losses due to collision

This special issue celebrates 100 years since the birth of Moisey Isaakovich Kaganov. This date is a personal event for us, since Moisey Issakovich (or Musik, for his friends and close ones) is the father of one of us, and the grandfather of the other. In addition, we have both been his students. We received the problem discussed in this paper by succession. In 1949 Ilya Mikhailovich Lifshitz was interested in studying electrodynamic and elastic properties of solids, and this analysis required knowledge of the corresponding Green’s functions. He suggested to his two graduate students, Moisey Kaganov and Victor Tsukernik, to calculate the displacement vector caused by an instant point source acting at the surface of an elastic half-space. At that time they had chosen a different topic, and the problem hibernated until the early 1990s, when Moisey Issakovich suggested it as a subject for a Master’s thesis for one of us (ML) to be conducted under the supervision of the other one (IK). The results have been published in papers I. M. Kaganova and M. L. Litinskaia, Phys. Lett. A 200, 365 (1995)1 and I. M. Kaganova and M. L. Litinskaia, Phys. Lett. A 200, 375 (1995).2 The first paper discussed the derivation of the normal component of the displacement vector. We showed that the displacement can be calculated as an integral in the complex plane, and examined the displacement at the surface of the half-space and at the direction normal to the surface. We showed that the singularities of the displacement are linked to certain changes in the shape of the integration contour. In the second paper, we applied the expression for the normal displacement to the calculation of the elastic energy due to an external load, and found the amount of energy lost by a small ball incident onto an elastic half-space. In this publication, we expand the analysis by investigating the singularities of the displacement vector in an arbitrary point of the half-space, and briefly review our previous results.

Reversing Benzene/Cyclohexane Selectivity through Varying Supramolecular Interactions Using Aliphatic, Isoreticular MOFs.

Effective solid-state adsorbent materials, such as metal organic frameworks (MOFs), rely upon tailored void spaces for selective adsorption of one component from a mixture. This is particularly crucial when separating challenging mixtures such as benzene (Bz) and cyclohexane (Cy) requiring a highly expensive and energy intensive process. Employing bulky "3D-linkers" to construct MOFs leads to materials with unique, contoured pore shapes which consequently allow for significant control over guest adsorption preferences. Investigation into these selectivity preferences is key to identifying suitable materials for industrial separations and is an area currently underexplored. Here, we provide an in-depth investigation exploring the selectivity path between planar and 3D-linkers and their preference to adsorb either Cy or Bz. To validate this principle, the adsorption selectivity of Cy and Bz in 3DL-MOF-1 ([Zn4O(pdc)3] (pdc = bicylo[1.1.1]pentane-1,3-dicarboxylate), CUB-5, and MOF-5 was explored. MOF-5 exhibits a selective preference for Cy adsorption at low pressures, contrary to popular belief, while CUB-5 and 3DL-MOF-1 are Bz selective. DFT-D3 calculations and breakthrough simulations explore this behavior and highlight CUB-5 and MOF-5 as strong candidates for future separation materials.

A Novel Combined Level Set Model for Carpus Segmentation from Magnetic Resonance Images with Prior Knowledge aligned in Polar Coordinate System

Background and ObjectiveSegmentation on carpus provides essential information for clinical applications including pathological evaluations, therapy planning, wrist biomechanical analysis, etc. Along with the acquisition procedure of magnetic resonance (MR) technique, poor quality of wrist images (e.g., occlusion, low signal-to-noise ratio, and contrast) often causes segmentation failure. MethodsIn this work, to address such problems, a shape prior enhanced level set model was proposed. By transferring a shape contour in Cartesian Coordinate System (COS) into a curve in Polar Coordinate System (POS), parameters describing conventional shape invariance, i.e., translations, rotation, and scale were simplified into a single parameter for phase shift, which strongly improved algorithm efficiency. Given a training set in COS, a confidence interval representing the corresponding curves in POS was utilized as the shape prior set term in the model. Integrated with an edge detector, a local intensity descriptor, and a regularization term, the proposed method further possessed abilities against noise, intensity inhomogeneity as well as re-initialization problem. Images from 15 in-vivo acquired MR-datasets of the human wrist were used for validation. The performance of the proposed method has been compared with three state-of-the-art methods. ResultsWe reported a Dice Similarity Coefficient of 96.88±1.20%, a Relative Volume Difference of -1.53±3.01%, a Volume Overlap Error of 6.03±2.23%, a 95% Hausdorff Distance of 1.43±0.66 mm, an Average Symmetric Surface Distance of 0.50±0.17 mm, and a Root Mean Square Distance of 0.71±0.25 mm for the proposed method. The time consumption was 36.03±19.98 s. ConclusionsExperimental results indicated that, compared with three other methods, the proposed method achieved significant improvement in terms of accuracy and efficiency.