Angular Segment Research Articles

Convergence of Core Losses in a Permanent Magnet Machine, as Function of Mesh Density Distribution, a Case-Study Using Finite-Element Analysis

To limit numerical inaccuracies in electromagnetic finite element analysis, the mesh resolution needs to be set with care. Within electric vehicle propulsion, core losses are highly important while excessive simulation times should be avoided, due to the wide operating range. This paper investigates the procedure of achieving core loss convergence, in all parts of a permanent magnet synchronous machine, by varying mesh density. The finite element analysis is done in Ansys Maxwell and the core loss error is quantified by an estimated fully converged result. Two approaches to mesh tuning are compared. It is found that interdependence, between the mesh density in one part and the core loss in another, should be considered. The required mesh resolution is found to differ among operating points. Finally, the flexibility offered by this convergence method is shown. Once the convergence behaviour has been identified, a mesh can be found for any desired compromise of error and simulation time. For the investigated case, the estimated error in total core loss is below 1.2% when an angular machine segment covering one pole, is modelled with 15500 mesh elements. Reducing the number of mesh elements to 7200 gives an error below 3.3%.

The Course of the Angular Artery in the Midface: Implications for Surgical and Minimally Invasive Procedures.

Previous anatomic studies have provided valuable information on the 2-dimensional course of the angular segment of the facial artery in the midface and its arterial connections. The third dimension (ie, the depth of the artery) is less well characterized. The objective of the present study was to describe the 3-dimensional pathway of the angular segment of the facial artery and its relationship to the muscles of facial expression. The bilateral location and the depth of the midfacial segment of the facial artery was measured utilizing multi-planar computed tomographic image analyses obtained from contrast agent-enhanced cranial computed tomographic scans of 156 Caucasians aged a of 45.19 ± 18.7 years and with a mean body mass index of 25.05 ± 4.9 kg/m2. At the nasal ala, the mean depth of the main arterial trunk was 13.7 ± 3.7 mm (range, 2.7-25.0 mm), whereas at the medial canthus it was 1.02 ± 0.62 mm (range, 1.0-3.0 mm). This was reflected by the arteries' relationship to the midfacial muscles: at the nasal ala superficial to levator anguli oris in 62.0% but deep to the levator labii superioris alaeque nasi in 53.6%; at the medial canthus superficial to the levator labii superioris alaeque nasi in 83.1% and superficial to the orbicularis oculi in 82.7%. The results presented herein confirm the high variability in the course of the angular segment of the facial artery. Various arterial pathways have been identified providing evidence that, in the midface, there is no guaranteed safe location for minimally invasive procedures.

ОБГРУНТУВАННЯ ВИМОГ ДО СУЧАСНИХ СПОСОБІВ ТА ЗАСОБІВ ВИЗНАЧЕННЯ ЗАГАЛЬНОГО ТЕХНІЧНОГО СТАНУ БЕНЗИНОВИХ ТА ДИЗЕЛЬНИХ ДВИГУНІВ ВІЙСЬКОВИХ ЕЛЕКТРОСТАНЦІЙ ТА СИЛОВИХ УСТАНОВОК ЗРАЗКІВ ОЗБРОЄННЯ ТА ВІЙСЬКОВОЇ ТЕХНІКИ

Розглядаються вимоги до систем та пристроїв діагностування привідних двигунів військових електростанцій і силових установок бронетанкової і автотракторної техніки, обґрунтовується необхідність врахування додаткових показників, які забезпечують необхідну глибину та повноту контролю. На прикладі розроблених оригінальних технічних рішень обґрунтовуються способи та пристрої оцінювання технічного стану двигунів внутрішнього згоряння шляхом визначення ступеня нерівномірності кутової частоти обертання, розглядаються шляхи підвищення точності процесу вимірювань миттєвої кутової частоти обертання, засновані на відмові від виконання операції диференціювання та на впровадженні систем автоматичного фазового підстроювання, при визначенні швидкості й прискорення, організації безперервних вимірювань, використання при проведенні вимірювань виключення одного з працюючих циліндрів для оцінки його внеску в результуючу виробляєму потужність, врахуванні в процесі випробувань крутильних коливань, що виникають в пружній системі валопроводу і можуть вплинути на точність визначення кутових відрізків

JPEG and raw image files compared to direct measurement of the breast region.

Purpose:To compare JPEG and RAW image file extensions to direct measurement of the breast region.Methods:Points were marked on the breasts and arms of 40 female volunteers. The joining of these points in each hemibody formed seven linear segments, one angular segment and one median segment common to both hemibodies. Volunteers were photographed in a standardized fashion and evaluated by three raters using the software Adobe Photoshop CS6® and three image file extensions (RAW, high resolution JPEG and low resolution JPEG); values were compared to direct anthropometry.Results:All variables had interclass correlation coefficient higher than 0.8 (ICC>0.8). On average, all variables in all methods showed differences (p<0.05) when compared to direct measurement. A formula was created for each segment and each image file extension in comparison with the direct measurement.Conclusion:Measurements were similar among the correlated JPEG and RAW image file extensions but differed from the actual breast measurement obtained with a caliper.

Impact of Spatial Change on Tourism by Bridge Connections between Islands: A Case Study of Ganghwa County in South Korea

The purpose of this study is to (1) measure the change in street networks of islands that are connected by bridges using space syntax and verify the relationships among spatial centrality, traffic volume and tourism facilities (small accommodations) and (2) establish strategies for sustainable tourism management through identifying the impact of this island connection on tourism destinations. Ganghwa County (Ganghwa Island, Seokmo Island and Gyodong Island) in South Korea was chosen as the study area, and we applied the angular segment analysis (ASA) method by metric distance based on space syntax. The results of this study showed that the construction of sea-crossing bridges between islands affected street networks considering metric radii (on a local scale, a mid-scale and a global scale) and areas with high spatial centrality in the study area affected traffic volumes and increased the number of small accommodations following the construction of bridges. The core areas of the whole street network were analyzed, and alternative paths for tourist flow diffusion, tourism development, land use regulation and environmental education for responsible tourism were proposed as key strategies for sustainable tourism. The findings of this study will contribute to reducing the potential for social and ecological damage by providing practical management strategies for island tourism destinations connected by bridges.

The spatial organization of accessibility and functional hierarchy: The case of Israel

Accessibility is a well-known basic term in spatial science and planning and is inherently related to functional aspects of places and regions. Although previous studies have examined functional systems and spatial accessibility few have attended to the association among them across geographical scales. Our study attempts to fill this gap. Using the space syntax methodology, spatial accessibility was analyzed for the entire national road network of Israel across different geographic scales – from local culminating in the national scale. The analysis was based on angular segment analyses of the road center-line network. Following this, the correlation between spatial accessibility across scales and functional performance of employment and commuting flows was examined.The study findings show a significant correspondence and exposes transitions between local, regional and national spatio-functional systems. First, a significant correlation between local (2 km radius) accessibility levels of settlements with the number of employees and commuters. Second, the regional/metropolitan system (10–15 km radius) accessibility is highly correlated to the emergence of the main employment centers. Third, the main metropolitan areas are integrated at higher scale (from 30 km radius) and form together a core region characterized by high accessibility as well as well connectivity through commuting flows. In contrast, no substantial commuting flows were found within the periphery, as well as between periphery-core. The findings show clearly that this functional structure corresponds to the multi-scale accessibility levels of settlements. We conclude that the core region functions at multiple scales (local-regional-national) while the periphery functions mostly at a local scale.

A Relativistic Magnetron Operated With Permanent Magnets

The results of an experimental and a numerical study of a relativistic A6 magnetron with single radial microwave power output slot operating with angular segment (AS) NdFeB permanent magnets placed inside the anode vanes and cylindrical rod magnets inside the cathode are presented. With permanent magnets, ~10−7 s long pulses of tens of megawatts of microwave power with an electronic efficiency of ~7% are generated. The results of experiments and simulations show that electron losses near the poles of the anode magnets where magnetic field lines cross the anode-cathode gap limit the microwave generation efficiency.

Effect of walking speed on the intersegmental coordination of lower-limb segments in elderly adults

BackgroundAgeing brings profound changes in walking gait. For example, older adults reduce the modification of pelvic and trunk kinematics with walking speed. However, the modification of the coordination between lower-limb segments with age has never been investigated across various controlled speeds. Research questionIs the effect of speed on the intersegmental coordination different between elderly and young adults? MethodsNineteen senior and eight young adults walked on a treadmill at speeds ranging from 0.56 to 1.94 m s−1. The motion of the lower-limb segments in the sagittal plane was recorded by cinematography. When the angles of the thigh, shank and foot during a stride are plotted one versus the other, they describe loops constraint on a plane. The coordination between lower-limb segments was thus evaluated by performing a principal component analysis between the thigh, shank and foot elevation angles. The effect of speed and age on the intersegmental coordination was examined using a two-level linear mixed model ANOVA. ResultsIn both age groups the orientation of the plane changes with speed, due to a more in-phase shank and foot motion. However, the effect of speed on the covariation plane is lessened with age. SignificanceOur results demonstrate that there is an age-related specific adjustment of the intersegmental coordination to speed. In particular, older adults restrict their repertoire of angular segment motion. These differences in coordination are mainly related to different foot-shank coordination.

Urban Open Space’s Accessibility Assessment Using Angular Segment to Reinvent as Evacuation Shelter in Historic City

Urban Open Space’s Accessibility Assessment Using Angular Segment to Reinvent as Evacuation Shelter in Historic City

Multi-atlas cardiac PET segmentation

PurposeWe propose a multi-atlas based segmentation method for cardiac PET and SPECT images to deal with the high variability of tracer uptake characteristics in myocardium. In addition, we verify its performance by comparing it to the manual segmentation and single-atlas based approach, using dynamic myocardial PET. MethodsTwelve left coronary artery ligated SD rats underwent ([18F]fluoropentyl) triphenylphosphonium salt PET/CT scans. Atlas-based segmentation is based on the spatial normalized template with pre-defined region-of-interest (ROI) for each anatomical or functional structure. To generate multiple left ventricular (LV) atlases, each LV image was segmented manually and divided into angular segments. The segmentation methods performances were compared in regional count information using leave-one-out cross-validation. Additionally, the polar-maps of kinetic parameters were estimated. ResultsIn all images, the highest r2 template yielded the lowest root-mean-square error (RMSE) between the source image and the best-matching templates ranged between 0.91–0.97 and 0.06–0.11, respectively. The single-atlas and multi-atlas based ROIs yielded remarkably different perfusion distributions: only the multi-atlas based segmentation showed equivalent high correlation results (r2 = 0.92) with the manual segmentation compared with the single-atlas based (r2 = 0.88). The high perfusion value underestimation was remarkable in single-atlas based segmentation. ConclusionsThe main advantage of the proposed multi-atlas based cardiac segmentation method is that it does not require any prior information on the tracer distribution to be incorporated into the image segmentation algorithms. Therefore, the same procedure suggested here is applicable to any other cardiac PET or SPECT imaging agents without modification.

Belgrade's urban transformation during the 19th century: A space syntax approach

This paper focuses on the change in terms of spatial structure of the city centre of Belgrade occurred during the 19th century with the urban renewal and sprawl. Space Syntax methodology was used in order to analyse and quantify the spatial configuration properties of the old town inherited from the Medieval and Ottoman period, but also to understand the changes produced by the remodeling of the borough during the Principality of Serbia according to the academic architectural style. A scan from the Radoje Dedinac plan of Belgrade from 1815-1830 conserved at the City Museum of Belgrade has been used in order to capture the old town morphology. Despite an abundant literature describing the incredible metamorphosis of the oriental part of the old town, the sources that have scientifically evaluated the urban transformation produced are very few. The Space Syntax methodology helps filling this gap. Axial maps of Belgrade between 1815-1830 and of nowadays have been generated and analysed in order to capture spatial intelligibility and synergy of the city before and after the urban transformation. Finally angular segment analysis has been used to understand the spatial morphology of both the organic urban form and the modern grid system.

Subject specific angular waist of the optic nerve head nerve fiber layer allows follow up detection of local nerve fiber bundle loss

PurposeTo clarify if frontal plane angular Pigment epithelium central limit‐ Inner limit of the retina Minimal Distance (PIMD) measured with OCT has enough specific angular structure for detection of change of specific angular segments of PIMD over time within glaucoma subjects.MethodsA Topcon OCT‐2000 was used for capture of the 3D representations of the ONH. from one eye of each of totally 13 subjects with early stage primary open angle glaucoma. Altogether, 3 volumes were captured at two occasions within 3 months. PIMD was semi‐automatically segmented in each volume in 500 equally spaced angular segments distributed over 2Pi in the frontal plane.ResultsPlots of the angular distribution of PIMD for all subject revealed specific low angular frequency overlaid with higher intermediate angular frequencies specific for each subject. High angular frequencies appeared similar for all subjects. A fast Fourier transform of the angular PIMD revealed a high to low frequency content ratio, 0.12, consistent for all segmentations of PIMD‐2Pi. The rotational displacment of angular PIMD in the frontal plane among segmentations, volumes and occasions was determined with cross‐correlation. Then, all PIMD‐2Pi were phase adjusted over segments, volumes and occasions. Finally, the rotation of PIMD‐2Pi was adjusted to a standard rotation. This allows comparison of angular segments of PIMD‐2Pi between visits. The magnitude of different sources of variation were estimated with analysis of variance.ConclusionsAngular correction in the frontal plane of recordings of angular PIMD of the ONH allows comparison of angular segments of PIMD‐2Pi. This substantially increases the resolution of of an angular segment of PIMD. The resulting precision suggest that detection of an angular segment of PIMD is associated with better resolution than Humphrey visual field MD.

Evaluation of 4-D Reaction Integrals in the Method of Moments: Coplanar Element Case

Recently, the benefits of simultaneously treating source and testing integrals in the numerical evaluation of 4-D reaction integrals have been reported. The reported schemes usually first transform the reaction integral to parametric coordinates, and some combination of radial, angular, and/or line segment integrals is then used to treat coincident, edge-adjacent, or vertex-adjacent triangular source and test element pairs. However, advantages of the reported approaches are tempered by their lack of generality and severely degraded performance on poorly shaped elements, the latter caused primarily by the parametric transformations’ severe distortion of the kernel’s circularly concentric level contours. Here, for coplanar element pairs and kernels with 1/ $R$ singularities, we apply the surface divergence theorem twice to obtain a novel formula for 4-D reaction integrals, generalizing earlier schemes while retaining their benefits and without distorting the original configuration space. Numerical results illustrate the method’s efficiency, which is improved by employing appropriate transformations to further smooth the resulting integrands and hence accelerate their convergence. The reaction integral formula can be extended to noncoplanar elements.

Using Space Syntax For Estimation Of Potential Disaster Indirect Economic Losses

The paper is aimed at estimation of indirect economic losses resulting from natural disasters. Generally, these losses are defined as interruptions in economic activities and are not related to the damaged enterprises. Even limited physical damage to property and infrastructure caused by natural disaster can produce chain reaction of losses in supply chain within a certain region. The Space Syntax Methodology is developed and used for accessing the characteristics of buildings, cities or the surrounding space in general. Although the methodology was primarily developed as urban planning method, it was also applied in the field of social and economic networks. Various studies of poverty, crime, disaster management and real estate prices are based on this methodology. The economic activities within a specific area are in a state of equilibrium before a disastrous event occurs. The disaster will change the spatial configuration (streets, buildings and infrastructure) causing negative effect on the economic networks and business opportunities. The main assumption of the research is that potential indirect losses could be estimated by comparing the Space Syntax characteristics before and after a disastrous event by measuring the deterioration of links between economic enterprises. The methodology is applied in a practical study of urban area. OpenStreetMap data is used as road-centred map of the city of York. The Historical Flood Map of the UK Environment Agency is used to setup disaster event impact. The Angular Segment Analysis implemented in DepthmapX software is used as the main method for analysis. The study of applicable network measures shows that Normalised Angular Choice can be used as criteria for selecting alternatives for minimizing indirect costs caused by road network damages. At the same time, this methodology cannot be used for monetizing indirect costs or identifying losses in different economic sectors. The study approach does not contradict the main theoretical approaches and it gives new opportunities for research on disasters recovery.

Experimental characterization of a prototype secondary spectrometer for vertically scattering multiple energy analysis at cold-neutron triple axis spectrometers

A thorough experimental characterization of a multiplexing backend with multiple energy analysis on a cold-neutron triple axis spectrometer (cTAS) is presented. The prototype employs two angular segments (2θ-segments) each containing five vertically scattering analyzers (energy channels), which simultaneously probe an energy transfer range of 2meV at the corresponding two scattering angles. The feasibility and strength of such a vertically scattering multiple energy analysis setup is clearly demonstrated. It is shown, that the energy resolution near the elastic line is comparable to the energy resolution of a standard cTAS. The dispersion relation of the antiferromagnetic excitations in MnF2 has been mapped out by performing constant energy transfer maps. These results show that the tested setup is virtually spurion free. In addition, focusing effects due to (mis)matching of the instrumental resolution ellipsoid to the excitation branch are clearly evident.

A point-based angular analysis model for identifying attributes of spaces at nodes in street networks

The effects of the axial map as the key representation of the original space syntax have been questioned by some researchers because of the map’s discontinuity. To address this concern, angular segment analysis (ASA) was introduced. ASA calculates spatial depths by considering the turning angles of path segments in a street network. However, ASA cannot calculate the attributes of nodes connected to path segments in the network because it analyzes spaces by linear representation, as in the original space syntax.Because the attributes of the two ends (nodes) of a given path segment (link) are not equal to each other, and because they can affect pedestrian and vehicle movement and land use in a street network, the identification of the attributes at nodes (points) would be helpful in the detailed analysis of spaces in the network consisting of nodes and the segments connecting them.Accordingly, this study aims to develop an extended analysis model that can calculate the attributes of spaces at the nodes, including terminuses, bends, and junctions, in the network.To achieve this end, in this study we developed algorithms for a point-based angular analysis (PAA) to find the attributes of spaces at nodes (points), in contrast to ASA, which analyzes spaces using linear representations.As a result, this methodology can obtain distinct values for the attributes of two nodes at the ends of a path segment, through the calculation of spatial depths weighted by considering the turning angles and distances (lengths) along consecutive nodes for a route in the network. Through our methodology, it was identified that spatial configurations of street network affect the social and symbolic centralities of nodes in the network.We believe that our methodology can be a useful tool for planning urban streets and for deriving spatial and social relationships in street networks.

Biomechanics of the upper limbs: 3D angular velocity, segment interaction and movement units in asymptomatic adults

Biomechanics of the upper limbs: 3D angular velocity, segment interaction and movement units in asymptomatic adults

Motion of a free cylinder inside a rotating water-filled drum

We report experimental results on the motion and levitation of a freely to-move heavy cylinder, of constant diameter and varying mass, inside a water-filled drum rotating around its horizontal axis. The resulting flow field and the cylinder dynamics were determined with the aid of flow visualizations and particle image velocimetry methods. The spatial tracking of the inner cylinder was done with the aid of Fourier cross correlation methods. The steady bulk flow field created by the drum rotation generated forces that make the inner cylinder to counter-rotate without contact with the drum walls. Testing different cylinder masses and rotating drum frequencies has shown that there exists a range of stable spatial positions of the inner cylinder describing an angular segment inside the drum flow. The cylinder frequency can be set to zero if we increase the drum frequency beyond a threshold value. Increasing the drum frequency produces a stronger secondary flow circulation which is the key-mechanism responsible of the counter-rotating cylinder frequency. At this point, the inner cylinder levitates with a constant separation from the drum walls close to half of its diameter. Tests on heavy hollow cylinders revealed that the fluid filling the cylinder remains at rest while the cylinder was under levitation with zero rotation frequency.

Normal T2 map profile of the entire femoral cartilage using an angle/layer-dependent approach.

To create standard T2 map profiles from the entire femoral cartilage of healthy volunteers in order to assess regional variations using an angular and layer-dependent approach. Twenty healthy knees were evaluated using 3T sagittal images of a T2 mapping sequence. Manual segmentation of the entire femoral cartilage was performed slice-by-slice by two raters using MatLab. Inter- and intrarater reliabilities were calculated using intraclass correlation coefficient (ICC) and Bland-Altman analysis. T2 values were analyzed with respect to specific locations (medial condyle, trochlea, and lateral condyle), angles to B0 , and layers of cartilage (whole, deep, and superficial). Inter- and intrarater reliability obtained from the entire femoral cartilage was excellent (ICC = 0.84, 0.86, respectively). The ICCs around the trochlea were lower than those of the medial and lateral condyle. Both the inter- and intrarater Bland-Altman plots indicated larger differences in pixel count are seen as the size of the angular segment becomes larger. T2 values were significantly higher in the superficial layer compared to the deep layer at each femoral compartment (P < 0.001). A magic angle effect was clearly observed, especially within the whole and deep layer over the medial and lateral femoral condyles, except for the superficial layer at the medial condyle. The normal T2 map profiles of the entire femoral cartilage showed variations in ICCs by location and in T2 values by angles and layers. These profiles can be useful for diagnosis of early cartilage degeneration in a specific angle and layer of each condyle and trochlea.

Spatial dosimetric sensitivity of contouring uncertainties in gynecological 3D-based brachytherapy

Background and purposeThis study aims to analyze subsections of the target volume that are sensitive to delineation uncertainties with respect to underdosage (spatial dosimetric uncertainty) in MRI-based brachytherapy of cervical cancer. Material and methodsA methodology was developed to simulate delineation uncertainties by shifting an angular segment of the contour perpendicular to the original HR-CTV. For shifts of 3, 6 and 9mm resulting D90 and D98 were calculated for the modified contour. The sensitivity of the dose plan to the locally introduced error was estimated by linear regression of D90 or D98 against the magnitude of the shift. The methodology was employed on 20 patients treated with tandem ring brachytherapy. ResultsTopographic maps resulting from the dosimetric sensitivity analysis showed both large spatial variations and substantial inter-patient variations. For all plans included the spatial sensitivity in D90 ranged from 0.0 to −1.6%/mm, correspondingly sensitivity in D98 ranged from 0 to −4.6%/mm. A significantly increased dosimetric sensitivity was found in anterior direction and the cranial part of the tumor (p<0.05). ConclusionsThe developed methodology identifies specific tumor regions and patients with increased risk of underdosage from delineation uncertainties in brachytherapy of cervical cancer.