Individual Contour Research Articles

Effects of α‐amylase and glycerol levels on the composition optimization of poly(β‐hydroxybutyrate‐co‐valerate)/starch blended biodegradable resin analyzed with response surface methodology

AbstractResponse surface methodology was used to analyze the effects of the enzyme level (X2) and glycerol level (X1) on objective attributes [water solubility index (WSI), water absorption index (WAI), and maximum loading (Y3)] of a cornstarch/poly(β‐hydroxybutyrate‐co‐valerate) blended composite. A rotatable central composite design was used to develop models for the objective responses. The experiments were run at barrel temperatures of 160, 160, 165, and 165°C, with a screw speed of 40 rpm and complete feeding (filling ratio = 1). Responses were most affected by changes in X2 and to a lesser extent by X1. Individual contour plots of the different responses were overlaid, and regions meeting the optimal WSI of 8.73%, WAI of 3.94 g of gel/g of dry weight, and Y3 of 304.17 N were established at an X2 of 5.43 g and an X1 of 120.79 mL. These predicted values for the optimal process conditions were in good agreement with the experimental data. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Optimization of the process variables for the synthesis of starch‐based biodegradable resin using response surface methodology

AbstractResponse surface methodology (RSM) was used to analyze the effect of different additives glycerol level (X1) and plasticizer level (X2) on the objective (water solubility index, water absorption index, and Max. loading) attributes of a cornstarch/PHBV blended composite. A rotatable central‐composite design (CCD) was used to develop models for the objective responses. The experiments were run at barrels temperatures 160, 160, 165, and 165°C, respectively, with screw speed 40 rpm and complete feeding (filling ratio = 1). Responses were most affected by changes in plasticizer level (X2) and to a lesser extent by glycerol level (X1). Individual contour plots of the different responses were overlaid, and regions meeting the predicted optimum water solubility index of 4.34%, water absorption index of 4.55 g gel/g dry wt, and Max. loading of 370.06 N were identified at the plasticizer level of 21.06 g, and the glycerol level of 96.11 mL, respectively. These predicted values for optimum process conditions were in good agreement with experimental data. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Materials: Easy to identify but hard to find

Human observers are very good at deducing the material composition of an object from its visible surfaces. Sharan (2009) has shown that a 40 msec exposure is adequate to determine if an object is made of wood, cloth, glass, etc. The visual signatures that define these materials have not been identified ,but it seems likely that some statistical regularities make one surface look like plastic and another like fur. Statistical properties like mean orientation can be extracted from textures without analyzing the orientation of individual contours in the texture. Are the statistical regularities or other properties that define materials used to guide attention? Can observers search efficiently for cloth among stone or glass among paper? To assess this, we used Sharan’s stimuli; moderate close-up views of objects made from nine material categories: plastic, fabric, glass, leather, metal, paper, stone, water, & wood. Observers searched for targets of one category. On each trial, distractors were drawn from one other category. Search was inefficient (Hits: 35.9 msec/item, Absent: 78.4 msec/item). Perhaps Sharan’s stimuli were too heterogeneous. We tried again with simpler surfaces: square, frontal patches of water, wood, skin, stone, fur, and feather. This was still inefficient. We ran three conditions with target and distractor held constant. Feather among wood and fur among water were run in grayscale. Stone among fur was run in color. Of these, only feather among wood was close to efficient (Hit: 8.2 msec/item) but this may have been an orientation artifact. Most of the wood grain was vertically oriented while feathers were horizontally oriented. Thus, while it may be possible to extract material information very rapidly and, perhaps, even to appreciate a material properties without attention, material information cannot be used to efficiently guide attention to targets of one type of material among distractors of another.

Clinical Evaluation of Soft Tissue Organ Boundary Visualization on Cone-Beam Computed Tomographic Imaging

Cone-beam computed tomographic images (CBCTs) are increasingly used for setup correction, soft tissue targeting, and image-guided adaptive radiotherapy. However, CBCT image quality is limited by low contrast and imaging artifacts. This analysis investigates the detectability of soft tissue boundaries in CBCT by performing a multiple-observer segmentation study. In four prostate cancer patients prostate, bladder and rectum were repeatedly delineated by five observers on CBCTs and fan-beam CTs (FBCTs). A volumetric analysis of contouring variations was performed by calculating coefficients of variation (COV: standard deviation/average volume). The topographical distribution of contouring variations was analyzed using an average surface mesh-based method. Observer- and patient-averaged COVs for FBCT/CBCT were 0.09/0.19 for prostate, 0.05/0.08 for bladder, and 0.09/0.08 for rectum. Contouring variations on FBCT were significantly smaller than on CBCT for prostate (p< 0.03) and bladder (p < 0.04), but not for rectum (p < 0.37; intermodality differences). Intraobserver variations from repeated contouring of the same image set were not significant for either FBCT or CBCT (p < 0.05). Average standard deviations of individual observers' contour differences from average surface meshes on FBCT vs. CBCT were 1.5 vs. 2.1 mm for prostate, 0.7 vs. 1.4 mm for bladder, and 1.3 vs. 1.5 mm for rectum. The topographical distribution of contouring variations was similar for FBCT and CBCT. Contouring variations were larger on CBCT than FBCT, except for rectum. Given the well-documented uncertainty in soft tissue contouring in the pelvis, improvement of CBCT image quality and establishment of well-defined soft tissue identification rules are desirable for image-guided radiotherapy.

Further experience with modification of an intraluminal button for hands-free tracheoesophageal speech after

Tracheoesophageal (TE) speech using a voice prosthesis and hands-free speaking valve with an intraluminal attachment is the gold standard for voice restoration after total laryngectomy. Modification of a standard self-retaining silicone cannula or laryngectomy button often aids in the attachment of a speaking valve within the tracheal lumen for hands-free TE speech production. An increased number of laryngectomized individuals are able to achieve hands-free TE speech when the standard length, flange, and diameter of a silicone button is customized to accommodate individual tracheostomal contours. A technique is presented for modification of a standard silicone laryngectomy button to facilitate hands-free TE speech after total laryngectomy. (J Prosthet Dent 2009;102:328-331) Tracheoesophageal (TE) speech using a voice prosthesis and hands-free speaking valve with an intraluminal attachment is the gold standard for voice restoration after total laryngectomy. Modification of a standard self-retaining silicone cannula or laryngectomy button often aids in the attachment of a speaking valve within the tracheal lumen for hands-free TE speech production. An increased number of laryngectomized individuals are able to achieve hands-free TE speech when the standard length, flange, and diameter of a silicone button is customized to accommodate individual tracheostomal contours. A technique is presented for modification of a standard silicone laryngectomy button to facilitate hands-free TE speech after total laryngectomy. (J Prosthet Dent 2009;102:328-331)

Three-dimensional Ultrasound Quantification of Intensive Statin Treatment of Carotid Atherosclerosis

This study was designed to evaluate 3-D ultrasound (3DUS)–derived vessel wall volume (VWV), a 3-D measurement of the carotid artery intima and media, including atherosclerotic plaque, in patients enrolled in a randomized placebo-controlled three-month study of intensive atorvastatin treatment. Thirty-five subjects with carotid stenosis >60% who provided written informed consent and completed a randomized, double-blind, placebo-controlled study were evaluated at baseline and at three months after receiving either 80 mg atorvastatin (16 subjects, nine male, mean age 68 ± 8.6 y) or placebo (19 subjects, 15 male, mean age 70 ± 9.4 y) daily. 3DUS images were acquired and 3DUS VWV was manually segmented by a single observer. Individual lumen and wall segmentation contours were also used to generate carotid atherosclerosis thickness difference maps by establishing correspondence between points along the vessel wall and lumen segmentation contour surfaces, and digitally subtracting registered baseline and follow-up thickness maps. 3DUS VWV increased by 70 ± 140 mm 3 (+4.9 ± 10.3%) in the placebo group and decreased by 30 ± 110 mm 3 (-1.4 ± 7.7%) in the atorvastatin group ( p < 0.05). Two-dimensional maps generated from the VWV measurements show localized heterogeneity and vessel wall thickness changes for all subjects, mainly in the common carotid artery. Carotid 3DUS VWV is a quantitative measure of atherosclerosis burden including the intima, media and plaque, with sensitivity to detect changes over short periods of time. Quantitative VWV thickness difference maps provide visual evidence of the spatial and temporal dynamics of carotid artery changes. (E-mail: gep@imaging.robarts.ca)

Effects of glycerol and ethylene–acrylic acid on composition optimization of PVOH/starch‐blended biodegradable resin using response surface methodology

AbstractResponse surface methodology was used to analyze the effect of glycerol (X1) and ethylene–acrylic acid (EAA) level (X2) on the objective (water solubility index (WSI), water absorption index (WAI), and tensile strength) attributes of a poly(vinyl alcohol) (PVOH)/starch‐blended plastic resin. A rotable central composite design was used to develop models for the objective responses. The experiments were run with different barrel temperatures, such as zone 1: 100°C, zone 2: 100°C, zone 3: 105°C, and zone 4: 105°C, respectively, with a feed rate of 20 g/min and screw speed of 25 rpm. Responses were most affected by changes in glycerol level (X1) and to a lesser extent by EAA level (X2). Individual contour plots of the different responses were overlaid, and regions meeting the optimum WSI of 6.10%, WAI of 5.57 g gel/g dry wt, and tensile strength of 62.14 MPa were identified at the glycerol level of 72.41 mL and the EAA level of 36.03 g, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

SU‐FF‐I‐121: Development of An Organ Surface Statistical Model for Uncertainty‐Weighted Deformable Image Registrations

Purpose: To develop an organ surface statistical model for uncertainty‐weighted probabilistic deformable registrations. Materials and Methods: The contours of the prostate, the bladder, and the rectum were manually delineated by five observers on fan beam CT images of four prostate patients. The reliability of the organ boundary delineation was estimated by calculating the intra‐observer, the inter‐observer, and the inter‐modality variability (e.g., standard deviation) of the organ boundary surfaces. For each set of contours, an average surface was computed by first superimposing individual organ contours and generating a composite bitmap image. Then after smoothing, a matching tetrahedron algorithm was used to extract the average surface mesh. The distance map between each individual segmentation and the average surface mesh can be calculated based on the normal defined on 1) each vertex or 2) each triangle of the average mesh. A simple 3D visualization program was developed using OpenGL to interactively viewing 3D organ surfaces and standard deviation surface maps. Results: Population‐based organ surface statistical models of the prostate, the bladder, and the rectum were created by mapping the patient specific standard deviation surface maps to the population‐averaged surface. 3D visualization indicates that the boundary uncertainties are anatomical location dependent. Conclusions: We proposed a general method for objectively constructing surface maps of uncertainties derived from topologically complex organ boundary segmentations from multiple observers. The computed boundary uncertainties can be used as weighting factors for a surface‐based probabilistic deformable registration.Supported in part by NIH grant P01CA116602

Water distribution under trickle irrigation predicted using artificial neural networks

An artificial neural network (ANN) technology is presented as an alternative to physical-based modeling of subsurface water distribution from trickle emitters. Three options are explored to prepare input–output functional relations from a database created using a numerical model (HYDRUS-2D). From the database the feasibility and advantages of the three alternative options are evaluated: water-content at defined coordinates, moment analysis describing the shape of the plume, and coordinates of individual water-content contours. The best option is determined in a way by the application objectives, but results suggest that prediction using moment analyses is probably the most versatile and robust and gives an adequate picture of the subsurface distribution. Of the other two options, the direct determination of the individual water contours was subjectively judged to be more successful than predicting the water content at given coordinates, at least in terms of describing the subsurface distribution. The results can be used to estimate subsurface water distribution for essentially any soil properties, initial conditions or flow rates for trickle sources.

Flexible isosurfaces: Simplifying and displaying scalar topology using the contour tree

The contour tree is an abstraction of a scalar field that encodes the nesting relationships of isosurfaces. We show how to use the contour tree to represent individual contours of a scalar field, how to simplify both the contour tree and the topology of the scalar field, how to compute and store geometric properties for all possible contours in the contour tree, and how to use the simplified contour tree as an interface for exploratory visualization.

Composition optimization of poly(vinyl alcohol)‐/cornstarch‐blended biodegradable composite using response surface methodology

AbstractResponse surface methodology was used to analyze the effect of amylase level (X1) and glycerol level (X2) on the objective [water solubility index (WSI), water absorption index (WAI), and Max. loading] attributes of a poly(vinyl alcohol)‐/cornstarch‐blended composite. A rotable central‐composite design (CCD) was used to develop models for the objective responses. The experiments were run at die temperature 100°C with a feed rate of 25 g/min and a screw speed of 35 rpm. Responses were most affected by changes in the amylase level (X1) and to a lesser extent by glycerol level (X2). Individual contour plots of the different responses were overlaid, and regions meeting the optimum WSI of 3.03 (%), WAI of 5.08 (g gel/g dry wt), and Max. loading of 29.36 (N) were identified at the amylase level of 2.8 (mL) and the glycerol level of 92.2 (mL), respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Interactive Comparison of Scalar Fields Based on Largest Contours with Applications to Flow Visualization

Understanding fluid flow data, especially vortices, is still a challenging task. Sophisticated visualization tools help to gain insight. In this paper, we present a novel approach for the interactive comparison of scalar fields using isosurfaces, and its application to fluid flow datasets. Features in two scalar fields are defined by largest contour segmentation after topological simplification. These features are matched using a volumetric similarity measure based on spatial overlap of individual features. The relationships defined by this similarity measure are ranked and presented in a thumbnail gallery of feature pairs and a graph representation showing all relationships between individual contours. Additionally, linked views of the contour trees are provided to ease navigation. The main render view shows the selected features overlapping each other. Thus, by displaying individual features and their relationships in a structured fashion, we enable exploratory visualization of correlations between similar structures in two scalar fields. We demonstrate the utility of our approach by applying it to a number of complex fluid flow datasets, where the emphasis is put on the comparison of vortex related scalar quantities.

A Cross-Coupled Iterative Learning Control Design for Precision Motion Control

This paper presents an improved method for precision motion control by combining individual axis iterative learning control (ILC) and cross-coupled ILC (CCILC) into a single control input. CCILC is a new method in which a multi-axis cross-coupled controller (CCC) is reformatted into a single-input single-output (SISO) ILC format. Applying the techniques of ILC to CCC enables learning of the cross-coupled error which leads to a modified control signal and subsequent improvements in the contour trajectory tracking performance. In this paper, performance of the combined ILC and CCILC system is compared to standard feedback control through computer simulations and experimental testing on a Cartesian robotic system. Sufficient stability and convergence properties for the combined system are presented along with a modified approach for determining monotonic convergence of systems that are computationally challenging. The combined design is shown to enhance the precision motion control of the robotic system through performance improvements in individual axis tracking and contour tracking.

A qualitative and a quantitative analysis of an auto-segmentation module for prostate cancer

Purpose This work describes the clinical validation of an automatic segmentation algorithm in CT-based radiotherapy planning for prostate cancer patients. Material and methods The validated auto-segmentation algorithm (Smart Segmentation, version 1.0.05) is a rule-based algorithm using anatomical reference points and organ-specific segmentation methods, developed by Varian Medical Systems (Varian Medical Systems iLab, Baden, Switzerland). For the qualitative analysis, 39 prostate patients are analysed by six clinicians. Clinicians are asked to rate the auto-segmented organs (prostate, bladder, rectum and femoral heads) and to indicate the number of slices to correct. For the quantitative analysis, seven radiation oncologists are asked to contour seven prostate patients. The individual clinician contour variations are compared to the automatic contours by means of surface and volume statistics, calculating the relative volume errors and both the volume and slice-by-slice degree of support, a statistical metric developed for the purposes of this validation. Results The mean time needed for the automatic module to contour the four structures is about one minute on a standard computer. The qualitative evaluation using a score with four levels (“not acceptable”, “acceptable”, “good” and “excellent”) shows that the mean score for the automatically contoured prostate is “good”; the bladder scores between “excellent” and “good”; the rectum scores between “acceptable” and “not acceptable”. Using the concept of surface and volume degree of support, the degree of support given to the automatic module is comparable to the relative agreement among the clinicians for prostate and bladder. The slice-by-slice analysis of the surface degree of support pinpointed the areas of disagreement among the clinicians as well as between the clinicians and the automatic module. Conclusion The efficiency and the limits of the automatic module are investigated with both a qualitative and a quantitative analysis. In general, with efficient correction tools at hand, the use of this auto-segmentation module will lead to a time gain for the prostate and the bladder; with the present version of the algorithm, modelling of the rectum still needs improvement. For the quantitative validation, the concept of relative volume error and degree of support proved very useful.

The development of a 3D risk analysis method

Much attention has been paid to the quantitative risk analysis (QRA) research in recent years due to more and more severe disasters that have happened in the process industries. Owing to its calculation complexity, very few software, such as SAFETI, can really make the risk presentation meet the practice requirements. However, the traditional risk presentation method, like the individual risk contour in SAFETI, is mainly based on the consequence analysis results of dispersion modeling, which usually assumes that the vapor cloud disperses over a constant ground roughness on a flat terrain with no obstructions and concentration fluctuations, which is quite different from the real situations of a chemical process plant. All these models usually over-predict the hazardous regions in order to maintain their conservativeness, which also increases the uncertainty of the simulation results. On the other hand, a more rigorous model such as the computational fluid dynamics (CFD) model can resolve the previous limitations; however, it cannot resolve the complexity of risk calculations. In this research, a conceptual three-dimensional (3D) risk calculation method was proposed via the combination of results of a series of CFD simulations with some post-processing procedures to obtain the 3D individual risk iso-surfaces. It is believed that such technique will not only be limited to risk analysis at ground level, but also be extended into aerial, submarine, or space risk analyses in the near future.

A Method for Vehicle Count in the Presence of Multiple-Vehicle Occlusions in Traffic Images

This paper proposes a novel method for accurately counting the number of vehicles that are involved in multiple-vehicle occlusions, based on the resolvability of each occluded vehicle, as seen in a monocular traffic image sequence. Assuming that the occluded vehicles are segmented from the road background by a previously proposed vehicle segmentation method and that a deformable model is geometrically fitted onto the occluded vehicles, the proposed method first deduces the number of vertices per individual vehicle from the camera configuration. Second, a contour description model is utilized to describe the direction of the contour segments with respect to its vanishing points, from which individual contour description and vehicle count are determined. Third, it assigns a resolvability index to each occluded vehicle based on a resolvability model, from which each occluded vehicle model is resolved and the vehicle dimension is measured. The proposed method has been tested on 267 sets of real-world monocular traffic images containing 3074 vehicles with multiple-vehicle occlusions and is found to be 100% accurate in calculating vehicle count, in comparison with human inspection. By comparing the estimated dimensions of the resolved generalized deformable model of the vehicle with the actual dimensions published by the manufacturers, the root-mean-square error for width, length, and height estimations are found to be 48, 279, and 76 mm, respectively.

Consumer‐Based Optimization of a Third‐Generation Product Made from Peanut and Rice Flour

Indirectly puffed snacks were produced by an extrusion process with partially defatted (12% fat) peanut flour (30%, 40%, 50%) at different levels of screw speed (200, 300, 400 rpm) and feed rate (4, 5, 6 kg/h). Extrudates were dried to obtain half-products (11% to 12% MC) followed by puffing with deep-fat frying. The puffed snack prototypes were subjected to consumer acceptance test. Consumers rated higher than 6.0 (= like slightly) for all products produced within the experimental factor ranges on the attributes of crispness and texture, whereas consumer scores for appearance, color, flavor, and overall liking were lower than 6.0 for the product containing 50% peanut flour regardless of screw speed and feed rate. The product extruded with 50% peanut flour at screw speed of 400 rpm and feed rate of 6 kg/h received the lowest score of 5.5 on overall liking in a 9-point hedonic score. Predicted regression models indicated that feed rate had the largest effect on consumer attributes followed by peanut flour and screw speed. From the superimposed contour plot of individual contour plot of consumer attributes, the optimum region was identified as the area beginning at the 42.0% to 43.0% peanut flour and 4.0 kg/h feed rates, rising to a maximum at 45% peanut flour and 4.6 kg/h feed rates and decreasing to the 33.0% to 34.0% peanut flour and 6.0 kg/h feed rates. Verification confirmed the ability of predictive regression models to identify peanut-based snacks, which would be scored higher than 6.0 by consumer evaluation.

Time Trends of Ulcer Mortality in Europe

The aim of the present study was to follow the time trends of ulcer disease in a representative sample of European countries and assess whether the most recent behavior of peptic ulcer still fits the overall pattern governed by an underlying birth-cohort phenomenon. Mortality data from 6 countries between 1921 and 2004 were analyzed, including Denmark, France, Germany, The Netherlands, Spain, and Switzerland. The age-specific death rates of gastric and duodenal ulcers from each individual country were plotted as period-age and cohort-age contours. The data from the past 50-80 years show striking similarities among the 6 European countries. In all countries alike, the risk of dying from gastric and duodenal ulcer increased among consecutive generations born during the second half of the 19th century until shortly before the turn of the century, and then decreased in all subsequent generations. The time trends of gastric ulcer preceded those of duodenal ulcer by 10-30 years. The increase in nonsteroidal anti-inflammatory drug consumption or introduction of potent antisecretory medications have not affected the long-term downward trends of ulcer mortality. The birth-cohort pattern has continued to influence the temporal variations of peptic ulcer until most recently. The unique shape of the birth-cohort patterns of gastric and duodenal ulcers and their identical appearance in countries with different health care systems and varying political and socioeconomic histories reflect the overriding influence of Helicobacter pylori infection.

Three dimensional visualisation of human facial exposure to solar ultraviolet

A three dimensional computer model of the human face has been developed to represent solar ultraviolet exposures recorded by dosimeter measurements on a manikin headform under low cloud conditions and various solar zenith angles. Additionally, polysulfone dosimeters have been successfully miniaturised to provide the detailed measurements required across the face. The headform used in this research was scanned at 709 individual locations to make a wireframe mesh consisting of 18 vertical contours and 49 horizontal contours covering half the manikin's frontal facial topography. Additionally, the back of the headform and neck have also been scanned at 576 locations. Each scanned location has been used as a viable dosimeter position on the headform and represents a grid intersection point on the developed computer wireframe. A series of exposures recorded by dosimeters have been translated into three dimensional exposure ratio maps, representing ambient solar ultraviolet exposure. High dosimeter density has allowed for the development of individual topographic contour models which take into account complex variation in the face and improve upon previously employed techniques which utilise fewer dosimeters to interpolate exposure across facial contours. Exposure ratios for solar zenith angle ranges of 0 degrees -30 degrees, 30 degrees -50 degrees, and 50 degrees -80 degrees have been developed.

THE STUDY OF OPTIMUM OPERATING CONDITIONS OF EXTRUDED SNACK FOOD WITH TOMATO POWDER

ABSTRACT Tomatoes are an integral part of diets worldwide. Many population studies have established a link between dietary intake of tomato, a major source of a carotenoid antioxidant, lycopene, and reduced risk of chronic diseases. Response surface methodology was used to analyze the effect of screw speed (X1), moisture content (X2) and tomato powder content (X3) on the objective attributes (radial expansion ratio [Y1], bulk density [Y2], degree of gelatinization [DG], water absorption index [WAI] and hardness [Y5]) of an extruded snack food with tomato powder. A Box‐Behnken design was used to develop models for the objective responses. The experiments were performed at 100C with the following: feed rate, 19.2 kg/h; X1, 250 rpm; and die diameter, 3.98 mm. Individual contour plots of the different responses were overlaid. Regions meeting 3.22 optimum Y1, 0.13‐g/cm Y2, 81.25% DG, 5.12‐g gel/g dry weight WAI and 35.43‐N Y5 were identified at 12.5 and 25% X2 and X3, respectively.