Horizontal Overlap Research Articles

Analysis and Simulation of Lateral Collision Risk under Paired Approach

The paired approach can improve the efficiency of closely spaced parallel runways. Calculating the probability and frequency of horizontal overlap is an indispensable step when evaluating the horizontal collision risk of the paired approach. As the generation of horizontal overlap probability is closely related to horizontal position error, we propose a calculation method of horizontal overlap probability based on position error from the perspective of pilot operation. First, according to the principle of flight mechanics, the attitude adjustment model is established for the horizontal direction of the approach process, and the pilot’s operation model for various position errors is based on the concept of the stochastic process. This attitude adjustment model can replicates the process of the pilot operating the steering column to change the aircraft’s attitude. When combined with the pilot’s operation model, it is possible to simulate the position errors generated during the approach process. Building on this, the horizontal overlapping conditions of two aircraft are analyzed to simulate the horizontal overlap process in the paired approach. The duration and instances of overlap counted and the ratio between these results and the total running time give the overlap probability and frequency. Multiple simulations in MATLAB reveal that higher pilot operating accuracy shortens the time for the aircraft to align with the course, whereas lower accuracy leads to unstable horizontal position errors. Furthermore, the horizontal overlap in paired approaches primarily occurs at the beginning of the procedure, and enhancing the pilot’s operating accuracy does not significantly affect the probability and frequency of horizontal overlap.

The Effect of Some Parameters on Natural Occlusion in Different Ethnicities

Natural occlusion is the resultant of many components, such as muscles, temporomandibular joints, teeth, and neuromuscular systems, and thus plays an essential role in any dental treatment. This research aims to analyze some important features of occlusion in Malaysians. A clinical examination was conducted on 120 students at MAHSA University. The sample was equally divided by gender and ethnicity (Malays, Chineses, and Indians), their age ranged between 18 to 25 years. Results showed that the incidence of canine guidance and group function occlusions was 36% and 64% respectively. Angle’s classification analysis revealed that Class I included the highest ratio of group function, class II, division 1 incorporated more group function than canine protection, while class II division 2 had more canine protection. In Class III, the occurrence for both occlusal patterns was almost equal. Other findings were that subjects with reduced horizontal overlap (0-0.9mm.) showed a 45% group function occlusal pattern, while subjects with increased (7-8.9 mm.) horizontal overlap all had group function. On the other hand, when vertical overlap exceeds 3mm., the percentage of canine protection spikes sharply and it reaches more than 80% of the cases when vertical overlap stands out at 5mm. During edge-to-edge protrusion, 45 % of individuals had anterior and posterior teeth contact, while 55% had anterior teeth contact with posterior teeth disocclusion. Class II division 2 had only anterior teeth contact with posterior teeth disocclusion, while Class III had nearly only anterior teeth contact with posterior teeth contact. There was no statistical difference in types of occlusion among ethnic groups and genders. In conclusion, Angle’s Classification, horizontal and vertical overlaps affect the occlusal pattern types during lateral excursion and protrusion. A simple formula is presented to predict the vertical and horizontal overlaps.

A Comparison of PortrayTM multimodal functions, stationary intraoral tomosynthesis, and 2D in the reduction of proximal surface overlap in bitewing radiography

ObjectiveCompare the proximal surface overlap of adjacent posterior teeth between images acquired with the PortrayTM (Surround Medical Systems, Morrisville, NC) stationary intraoral tomosynthesis (s-IOT), and 2D modes Methods and MaterialsBitewing images were acquired with a size-2 CMOS detector specifically designed for PortrayTM. Eleven Dentsply Rinn adult manikins were exposed to acquire the images (2 premolar and 2 molar) per manikin using the 2D and tomosynthesis exposure modes. The exposure settings for the 2D were 7mA, 0.25s, 70 kVp and for tomosynthesis 7mA, 0.63s, 70kVp. Proprietary software reconstructed the tomosynthesis datasets. The generated slices were 0.5 mm apart and parallel to the detector plane. An experienced clinician (>10 years) exposed all images. Horizontal overlap between enamel of adjacent proximal surfaces was measured by a calibrated experienced clinician using the tools in the s-IOT software. Data were analyzed using the Wilcoxon signed rank test for comparison of proximal overlap. ResultsThe 440 exposed bitewings resulted in 44 paired images. Analysis included only the 293 paired surfaces visible with both techniques. 147 surfaces were excluded that did not appear with both modalities. 2D images resulted in a median overlap of 0%, a minimum of 0%, a maximum of 100%, interquartile range 44%. Tomosynthesis images resulted in a median overlap of 0%, a minimum of 0%, a maximum of 71% and an interquartile range of 71%. The difference was statistically significant (p<. 0001). ConclusionThe s-IOT generated images substantially reduced proximal surface overlap compared to the 2D mode. Statement of Ethical ReviewEthical Review or exemption was not warranted for this study.

Variable Baseline and Flexible Configuration Stereo Vision Using Two Aerial Robots.

In this work, a new method for aerial robot remote sensing using stereo vision is proposed. A variable baseline and flexible configuration stereo setup is achieved by separating the left camera and right camera on two separate quadrotor aerial robots. Monocular cameras, one on each aerial robot, are used as a stereo pair, allowing independent adjustment of the pose of the stereo pair. In contrast to conventional stereo vision where two cameras are fixed, having a flexible configuration system allows a large degree of independence in changing the configuration in accordance with various kinds of applications. Larger baselines can be used for stereo vision of farther away targets while using a vertical stereo configuration in tasks where there would be a loss of horizontal overlap caused by a lack of suitable horizontal configuration. Additionally, a method for the practical use of variable baseline stereo vision is introduced, combining multiple point clouds from multiple stereo baselines. Issues from using an inappropriate baseline, such as estimation error induced by insufficient baseline, and occlusions from using too large a baseline can be avoided with this solution.

The Mechanics of Bioinspired Stiff-to-Compliant Multi-Material 3D-Printed Interfaces.

Complex interfaces that involve a combination of stiff and compliant materials are widely prevalent in nature. This combination creates a superior assemblage with strength and toughness. When combining two different materials with large stiffness variations, an interfacial stress concentration is created, decreasing the structural integrity and making the structure more prone to failure. However, nature frequently combines two dissimilar materials with different properties. Additive manufacturing (AM) and 3D printing have revolutionized our engineering capabilities concerning the combination of stiff and compliant materials. The emergence of multi-material 3D-printing technologies has allowed the design of complex interfaces with combined strength and toughness, which is often challenging to achieve in homogeneous materials. Herein, we combined commercial 3D-printed stiff (PETG) and compliant (TPU) polymers using simple and bioinspired interfaces using a fused deposition modeling (FDM) printer and characterized the mechanical behaviors of the interfaces. Furthermore, we examined how the different structural parameters, such as the printing resolution (RES) and horizontal overlap distance (HOD), affect the mechanical properties. We found that the bioinspired interfaces significantly increased the strain, toughness, and tensile modulus compared with the simple interface. Furthermore, the more refined printing resolution elevated the yield stress, while the increased overlap distance mostly elevated the strain and toughness. Additionally, 3D printing allows the fabrication of other complex designs in the stiff and compliant material interface, allowing various tailor-designed and bioinspired interfaces. The importance of these bioinspired interfaces can be manifested in the biomedical and robotic fields and through interface combinations.

Image histogram decomposition method for particle sizing – A numerical simulation study

Scanning probe microscopy is a useful tool in nanoscience. The effective application of nanotechnologies in various fields requires a knowledge of the characteristic attributes of nanoparticles such as shape, dimensions and statistical distribution, and a wide spectrum of experimental and theoretical methods based on various principles have been developed to determine these characteristics. Image histograms offer a global overview of the characteristics of an image. Their shape can encode specific statistical properties of displayed objects such as the distribution function in the case of similar and scalable objects. The model of height histogram presented here proposes a method which solves the long-term problem of processing images of extremely dense particle distributions. The method is based on the principle of the superposition of histograms of individual particles whose topographic surface is described by a parametric model. The resulting height histogram is defined by a convolution of the model of the particle histogram with the distribution function of particle size, with this construction forming the basis of the regression model. The parameters of the distribution function can be obtained via the optimization of the model. The method has been tested on artificially generated configurations of particles of various shapes and size distributions. Each of these configurations creates a topographic surface which is transformed into an image, and the heights obtained from the image allow a histogram to be calculated. Firstly, various configurations of particles are simulated without the presence of any disruptive influences. Next, several experimental effects are evaluated separately (for example, the background, particle shape irregularity and particle overlap). The decomposition of the histogram by the regression model on artificially generated images shows the robustness of the method with respect to particle density, partial horizontal overlap, randomly generated backgrounds and random fluctuations in particle shape. However, the method is sensitive to uniform changes in particle shape, a factor which limits its use to particles with known parametric models of their shape which allow the means of their parameters to be estimated.

Severity and Treatment Difficulty of Impacted Maxillary Canine among Orthodontic Patients in Riyadh, Saudi Arabia.

Background: The current study aimed to evaluate the severity and treatment difficulty of impacted maxillary canines and their relationship with gender, age group, and bucco-palatal position. Methods: A retrospective cross-sectional study was conducted from 2017 to 2021. Patients’ data and panoramic radiography were obtained from the orthodontic clinic at King Saud University’s Dental University Hospital in Riyadh, Saudi Arabia. The severity factors and treatment difficulty index were used to assess the impacted maxillary canines. Statistical analyses were performed utilizing a chi-square test for categorical variables and an independent t-test for numerical variables, and a p-value of ≤0.05. Results: There were 171 impacted maxillary canines in total, with a female-to-male subject ratio (11:8) and a mean age (18.7 years). Overall, 77.2% of impacted upper canines were found to be palatal. The severity of canine impaction parameters showed no significant sex or age group predilection. Buccally impacted maxillary canines were characterized by a preferable angulation to the midline, compared to the palatally impacted maxillary canines (p = 0.012). The horizontal overlap of the impacted maxillary canine cusp tip revealed a significant association with the bucco-palatal position of the impacted canine (p < 0.001). Palatal impaction was located more frequently in sectors 3 and 4. Male patients were found to have a higher total score in terms of the treatment difficulty index relative to females (p = 0.046). Conclusion: Despite the severity parameters having revealed no significant gender predilection, males were found to have higher treatment difficulty in maxillary canine impaction than females. The severity of the palatally impacted canine is greater than that of buccal impaction in terms of angulation to the midline and horizontal overlap.

The proportionality of merger remedies in differentiated product markets

Horizontal mergers that raise competition concerns may require divestitures that eliminate the identified concerns. At the same time, divestitures should be proportionate, not going above and beyond what is necessary to eliminate the identified concerns. In this article, we argue that in differentiated product markets out-of-market substitutes exert stronger competitive pressure on some products within the relevant product market than on others. As a result, a divestiture of products that are subject to strong competitive pressure from out-of-market substitutes may not be needed if other products that are subject to weaker competitive pressure are divested. A simplistic solution that requires divestitures in all areas of horizontal overlap could result in overly broad remedies that violate the proportionality principle.

Study on the Probability of Paired Approach Horizontal Overlap

Study on the Probability of Paired Approach Horizontal Overlap

FIRST RESULTS OF PROCESSING DIGITIZED V-PLATES TAKEN WITH THE TAUTENBURG 2m SCHMIDT TELESCOPE

The process of treatment of about 500 digitized plates has started in MAO NAS of Ukraine. Plates were taken with the Tautenburg 2m Schmidt telescope in 1963-1989. Linear dimensions of plates are 24x24 cm with a working field of 3.3x3.3 degrees and a scale of 51.4 "/ mm. Astronegatives were digitized on the Tautenburg Plate Scanner in five strips with linear dimensions of 5 400x23 800 px. The software developed in MAO NAS of Ukraine for the image processing of these scans takes into account the horizontal overlap and the vertical offset of strips. The photometric range of fixed objects is 12 magnitudes, around V = 7 m - 19 m , due to the separation of objects into faint and bright parts by their images’ diameters. Positions of stars and other fixed objects are obtained in the GAIA DR2 reference system. Magnitudes are defined in the V-band of the Johnson color system. The resulted positional accuracy defined from 180 plates’ processing is σ RA,DEC = 0.10"for both coordinates, photometric error on the whole range of magnitudes is σ V = 0.14 m . The convergence of resulted magnitudes with ones from photoelectric standards’ data is 0.19 m . In parallel with image processing and plate data reduction, the search for minor planets’ images was carried out. Nine positions and magnitudes of 4 asteroids registered on the plates obtained in 1963-1965 were defined and used for further analysis.

Horizontal and vertical movements of immature dusky sharks Carcharhinus obscurus in relation to commercial longline fisheries in the western North Atlantic Ocean

BackgroundMany species of sharks, including the dusky shark Carcharhinus obscurus, are often incidentally captured in commercial pelagic and bottom longline fisheries. Incidental capture can lead to at-vessel or post-release mortality and can be detrimental to populations of threatened, endangered, or prohibited species. The estimated at-vessel mortality for dusky sharks can be high in longline fisheries and, to minimize mortality, time–area closures have been designated in the western North Atlantic Ocean to mitigate interactions with longline fisheries, yet incidental capture of dusky sharks is still common. We compared the vertical and horizontal movements of dusky sharks to the overall fishing effort and depth fished of commercial pelagic and bottom longline fisheries to determine when and where overlap is present that could lead to incidental capture.ResultsTwenty-one (n = 21) dusky sharks were tagged with pop-up archival transmitting satellite tags and all were immature animals (123–200 cm FL) apart from two individuals (230 and 300 cm FL). Sharks were tagged off the coasts of North Carolina (71%) and Florida (29%). Twenty tags (95%) reported and provided tracks between 1 and 107 days (median 15 days) and 10 tags (50%) remained on sharks for > 4 days. Most individuals remained within the bottom longline closed area off the coast of North Carolina during their time at liberty. Dusky sharks primarily occupied the 20–40 m depth range 26% of the time, and overlapped with bottom and pelagic longline gears 41% and 59% of the time, respectively. Overlap was highest in the winter and spring for both commercial fisheries.ConclusionsThe use of archival satellite telemetry in this study has provided valuable preliminary information on vertical and horizontal movements of immature dusky sharks in western North Atlantic Ocean. Dusky sharks may be more vulnerable to incidental capture in the pelagic longline fishery due to the high fishing effort, larger areas of horizontal overlap, and greater percentage of vertical overlap. This information will inform mitigation measures of commercial longline fisheries, which can work toward population rebuilding of the species.

Evaluation of Dental Status in Relation to Excessive Horizontal and Vertical Overlap in North Indian Population.

Introduction:Tooth wear (attrition) is a multifactorial entity, the pathogenesis of which involves many factors but the role of malocclusion cannot be undermined. Overjet and overbite play an important role in defining occlusion, hence they should also play an important role in causing attrition.Objectives:This study aims to evaluate the relationship of dental health status between the vertical and horizontal overlap.Materials and Methods:This study was conducted on 600 patients selected randomly from rural population which were divided into three equal groups as per the predefined criteria, namely, horizontal overlap, vertical overlap, and control group. All patients were examined for the tooth attrition.Results:In Group 1 – 73 patients out of 200 showed one or more teeth attrition, in Group 2 – 38 patients out of 200 showed one or more teeth attrition, and in the control group, 22 patients out of 200 showed one or more teeth attrition.Conclusion:It was concluded that both vertical and horizontal abnormal relationships of teeth play an important role in the etiology of attrition, with abnormal horizontal overlap being the more detrimental as compared to the vertical one.

Spatiotemporal interactions of native and introduced salmonid top predators in a large lake: implications for species restoration

Animal interactions are an integral part of a community’s function, with influences ranging from the spatiotemporal habitat use of species to population effects to ecosystem management. Numerous non-native species are established or maintained through stocking in freshwater ecosystems with the potential to affect restoration of native species. Using acoustic telemetry, this study quantified the spatiotemporal co-occurrence of the native top-predator lake trout (Salvelinus namaycush) with non-native Chinook salmon (Oncorhynchus tshawytscha) in Lake Ontario over 2.5 years. Core home range overlap was observed during the summer, with depth acting as a mechanism of segregation, but with potential for interactions during vertical exploration. Fine-scale individual pairwise interactions confirmed the home range results. No horizontal overlap was observed during the winter and spring, but confidence was lower due to poor instrument coverage in deeper water, which the two species may frequent in these seasons. These results demonstrate the importance of depth in understanding fish interactions and highlight the usefulness of considering pairwise species interactions for understanding ecosystem community function to resource managers with multiple projects involving both native and non-native species.

Evaluation of Image Quality of Bitewing Radiographs taken by UiTM Dental Students

Objectives: To evaluate the quality of bitewing radiograph taken by Universiti Teknologi MARA (UiTM) dental students during daily clinical practices and to evaluate the difference in caries lesions found on bitewing radiographs and clinical examination. Materials and method: 120 patients who attended the undergraduate dental clinic for dental examination were included in this study. The inclusion criteria were patients within the age range of 17-45 years old, possessing at least three sets of posterior teeth, with bitewing radiographs taken by undergraduate dental students. The number of caries lesions detected by clinical examination, bitewing radiographs, and a combination of both methods were recorded. The quality of 240 bitewing radiographs was classified into three categories; excellent, acceptable, and unacceptable. The frequency of radiographic errors; foreshortening/elongation, horizontal overlapping, inadequate film coverage, non-ideal centering and inadequate contrast and density were also evaluated. Results: The quality of bitewing radiographs are mostly accepted to be used as a diagnostic tool and one of the factors which commonly affected the quality of the bitewing is the overlapping of adjacent teeth. The highest number of caries lesions were detected radiographically (74%) compared with 25% caries by clinical examination. The majority of radiographs (71%, n=171) were deemed to be of acceptable quality, 39(16%) were excellent, and 30(13%) were diagnostically unacceptable. “Horizontal overlap” was the most common error detected on the radiographs (n=139, 57.9%), followed by “non-ideal centering” (n=93, 38.8%), “inadequate contrast” (n=46, 19.2%) and “inadequate film coverage” (n=24,10%). The highest number of caries lesions were detected radiographically (74%) compared with 25% caries by clinical examination. Conclusion: The quality of the majority of bitewing radiographs taken by undergraduate dental students in this institution is acceptable. However, given that more than half of the radiographs possessed horizontal overlapping error, caries diagnosis may have been underestimated. Further training and periodic audits are required to reduce the percentage of errors in bitewing radiographs amongst undergraduate dental students.

UAV-Based Gigapixel Panoramic Image Acquisition Planning with Ray Casting-Based Overlap Constraints

Panoramic imaging is information-rich, low-cost, and effective. In panoramic image acquisition, unmanned aerial vehicles (UAVs) have a natural advantage that owes to their flexibility and relatively large observation ranges. Using a panoramic gimbal and a single camera may be the most common means of capturing gigapixel panoramas. In order to manage the constraints of UAV power and facilitate the use of a variety of camera lenses, an effective and flexible method for planning UAV gigapixel panorama acquisitions is required. To address this need, a panoramic image acquisition planning method is proposed in this paper. The method defines image overlaps via a ray casting procedure and then generates an acquisition plan according to the constraints of horizontal and vertical overlap thresholds. This method ensures the completeness of the panorama by maintaining the overlap between adjacent images. Two experiments, including simulated and field cases, were performed to evaluate the proposed method through comparisons with an existing panorama acquisition plan. Results showed that the proposed method can capture complete panoramas with fewer images.

A fast luminosity monitor based on diamond detectors for the SuperKEKB collider

Abstract A fast luminosity monitor measuring the rate of the radiative Bhabha process at zero degree photon scattering angle based on diamond detectors was developed and successfully operated during the Phase-2 commissioning of SuperKEKB. The main purpose of this system, called LumiBelle2, is to provide: train integrated luminosity signals at 1 kHz with a relative precision better than 1% for luminosities higher than 1 0 34 c m − 2 s − 1 , input to a dithering feedback system designed to maintain an optimum horizontal overlap between the two colliding beams at the Interaction Point (IP), and bunch integrated luminosity signals at 1 Hz which are useful for machine tuning and beam parameters studies of the successive bunches along the train. In this paper, the design of the LumiBelle2 and Phase-2 results will be reported, including the evaluation of the single beam background, relative luminosity measurements and vertical beam size determinations at the IP using vertical offset scans.

A digital approach for 1-step formation of the supraimplant emergence profile at the time of immediate implant placement

An optimal soft tissue profile is essential for obtaining optimal esthetics in anterior implant-supported restorations. Commercially available cylindrical healing abutments do not mimic the shape of natural teeth and may create a poor peri-implant emergence. This article introduces a digital protocol to improve the formation of the supraimplant emergence profile with an individualized healing abutment fabricated by computer-aided design and computer-aided manufacture (CAD-CAM) at the time of implant placement. A benefit of this technique is obtaining optimal morphology of the peri-implant soft tissues, especially for teeth with increased horizontal overlap.

Processing Chain for Estimation of Tree Diameter from GNSS-IMU-Based Mobile Laser Scanning Data

Mobile laser scanning (MLS) is a progressive technology that has already demonstrated its ability to provide highly accurate measurements of road networks. Mobile innovation of the laser scanning has also found its use in forest mapping over the last decade. In most cases, existing methods for forest data acquisition using MLS result in misaligned scenes of the forest, scanned from different views appearing in one point cloud. These difficulties are caused mainly by forest canopy blocking the global navigation satellite system (GNSS) signal and limited access to the forest. In this study, we propose an approach to the processing of MLS data of forest scanned from different views with two mobile laser scanners under heavy canopy. Data from two scanners, as part of the mobile mapping system (MMS) Riegl VMX-250, were acquired by scanning from five parallel skid trails that are connected to the forest road. Misaligned scenes of the forest acquired from different views were successfully extracted from the raw MLS point cloud using GNSS time based clustering. At first, point clouds with correctly aligned sets of ground points were generated using this method. The loss of points after the clustering amounted to 33.48%. Extracted point clouds were then reduced to 1.15 m thick horizontal slices, and tree stems were detected. Point clusters from individual stems were grouped based on the diameter and mean GNSS time of the cluster acquisition. Horizontal overlap was calculated for the clusters from individual stems, and sufficiently overlapping clusters were aligned using the OPALS ICP module. An average misalignment of 7.2 mm was observed for the aligned point clusters. A 5-cm thick horizontal slice of the aligned point cloud was used for estimation of the stem diameter at breast height (DBH). DBH was estimated using a simple circle-fitting method with a root-mean-square error of 3.06 cm. The methods presented in this study have the potential to process MLS data acquired under heavy forest canopy with any commercial MMS.

Evaluation of Periodontal Status after Orthodontic Treatment: A Pilot Study on Patients with Stage IV/Grade C periodontitis.

To evaluate whether the periodontal status was affected in patients with stage IV/grade C periodontitis after orthodontic treatment. Twenty-four patients with stage IV/grade C periodontitis who received combined periodontal and orthodontic treatment were included in this study. Probing depth (PD), bleeding on probing (BOP) and percentage of relative bone height (RBH%) were measured and calculated. Parameter changes before and after orthodontic treatment, and their differences between teeth adjacent to extraction sites (TAES) and teeth nonadjacent to extraction sites (TNES) were compared. Three-level analysis was performed to test the influential factors of PD and RBH% reduction after orthodontic treatment. No change of PD, BOP% and RBH% was detected after orthodontic treatment. No difference of PD, BOP% and RBH% was detected between TAES and TNES. BOP negative, excessive horizontal overlap, excessive vertical overlap, crowding, PD at T0 (the last periodontal visit before orthodontic treatment) and RBH% at T0 were positively associated with PD reduction after orthodontic treatment. Being female, excessive horizontal overlap, excessive vertical overlap, crowding, PD at T0 and RBH% at T0 were positively associated with a RBH% reduction. Space was negatively associated with a RBH% reduction. Periodontal stability can be obtained for patients with stage IV/grade C periodontitis after orthodontic treatment. Orthodontic treatment with extraction was safe for patients with severe periodontitis, however, attention should be given to TAES.

Functionally orientated/systemic approach to orthodontic treatment of severe class II division 1 malocclusions: an adapted device, the FABP

The orthodontic treatment of severe class II division 1 malocclusions is often difficult, which leads some specialists to offer a surgical correction of the overjet. Treatment is made complex by the value of the horizontal overlap as much as the « depth » of deep bite that is very often present alongside the malocclusion. This is why we are offering a treatment protocol including a FABP (Fixed Anterior Bite Plate) which will allow, if the patient cooperates, to correct the anatomic anomaly while concurrently establishing new masticatory cycles in order to stabilize and preserve the results obtained. It is this systemic approach of treatment that is the focus of this article.