Contour Size Research Articles

Crack growth simulation of multiple cracks systems applying remote contour interaction integrals

The paper presents a numerical procedure for the calculation of crack loading quantities related to multiple cracks systems in plane structures based on the theory of linear elastic fracture mechanics. Path-independent interaction integrals (I-integrals) are used to avoid special requirements concerning crack tip meshing and contour size. A straightforward implementation of the I-integral enables the accurate calculation of stress intensity factors considering multiple cracks and strongly curved crack faces. In contrast to the classical application, loading quantities are calculated efficiently by choosing large integration paths including all crack tips. A separation of the total interaction energy with respect to stress intensity factors allocated to specific crack tips is achieved by appropriately choosing the auxiliary fields. Numerical examples of crack propagation simulations under critical and subcritical conditions are presented and the resulting crack paths are verified by comparison with those obtained from conventional methods.

Current Readings: Radiologic Interpretation of the Part-Solid Nodule: Clinical Relevance and Novel Technologies

Persistent subsolid nodules, part-solid or pure ground-glass attenuation, are associated with primary lung adenocarcinoma, recently redefined by the International Association for the Study of Lung Cancer-American Thoracic Society-European Respiratory Society in 2011 and include newly categorized entities of adenocarcinoma in situ, minimally invasive adenocarcinoma, and lepidic-predominant adenocarcinoma. Awareness of the relationship of the subsolid nodule with adenocarcinoma has emerged in the era of high-resolution multidetector computed tomography (CT). This article highlights the role of noninvasive CT for subsolid nodules with an emphasis on the potential for quantitative measures to predict adenocarcinoma subtypes and their longitudinal behavior. Of particular importance is the knowledge that an increase in solid components on CT is an indication of progression. Continued experience in evaluating quantitative measures in combination with morphologic features, including margin contour, internal architecture, and nodule size, will further aid in guiding crucial decisions pertaining to the use of CT surveillance vs more invasive approaches including biopsy and surgical resection.

Manipulating femtosecond magnetism through pressure: First-principles calculations

Inspired by a recent pressure experiment in fcc Ni, we propose a simple method to use pressure to investigate the laser-induced femtosecond magnetism. Since the pressure effect on the electronic and magnetic properties can be well controlled experimentally, this leaves little room for ambiguity when compared with theory. Here we report our theoretical pressure results in fcc Ni: Pressure first suppresses the spin moment reduction and then completely diminishes it; further increase in pressure to 40 GPa induces a demagnetization-to-magnetization transition. To reveal its microscopic origin, we slide through the $L$-$U$ line in the Brillouin zone and find two essential transitions are responsible for this change, where the pressure lowers two valence bands, resulting in an off-resonant excitation and thus a smaller spin moment reduction. In the spin-richest $L$-$W$-${W}^{\ensuremath{'}}$ plane, two spin contours are formed; as pressure increases, the contour size retrieves and its intensity is reduced to zero eventually, fully consistent with the spin-dipole factor prediction. These striking features are detectable in time- and spin-resolved photoemission experiments.

Study of Constructed Wetland Plant Growth by Computer Image Processing (CIP)

This paper developed a kind of non-destructive measurement for the growth process of constructed wetland plant: doing image acquisitions of constructed wetland plant regularly through digital camera imaging; introducing image files to computer through interface, displaying them on the screen of computer; developed constructed wetland plant image and growth information extraction software under Visual C++ compiling integrated environment, users could acquire plant contour (realized by image edge recognition) and plant size (characterized by top projected leaf area) through human-machine interactive operation; designed constructed wetland plant (Phragmites communis) experiment to analyze the biomass change during the non-destructive measurement process. The biomass had good correlation with manual measured individual plant height, which proved that computer image processing based non-destructive measurement can provide reliable predictions for plant growth parameters.

Study of Constructed Wetland Plant Growth by Computer Image Processing (CIP)

This paper developed a kind of non-destructive measurement for the growth process of constructed wetland plant: doing image acquisitions of constructed wetland plant regularly through digital camera imaging; introducing image files to computer through interface, displaying them on the screen of computer; developed constructed wetland plant image and growth information extraction software under Visual C++ compiling integrated environment, users could acquire plant contour (realized by image edge recognition) and plant size (characterized by top projected leaf area) through human-machine interactive operation; designed constructed wetland plant (Phragmites communis) experiment to analyze the biomass change during the non-destructive measurement process. The biomass had good correlation with manual measured individual plant height, which proved that computer image processing based non-destructive measurement can provide reliable predictions for plant growth parameters.

Anatomy of scapes, bracts, and leaves of Paepalanthus sect. Diphyomene (Eriocaulaceae, Poales) and its taxonomic implications

Paepalanthus sect. Diphyomene comprises 18 species with a convoluted taxonomic history. Aiming to correlate anatomical structures with the systematics of this group and its relatives, we studied the anatomy of scapes, reproductive axis bracts, and leaves of 20 Paepalanthus species. Bracts and leaves show differences in epidermal cell thickening; mesophyll width; vascular bundle arrangement; presence or absence of a hypodermis; types of cells in the vascular bundle sheath extensions; margin shape and composition; and presence or absence of aquiferous parenchyma. Scapes differ in contour, rib number, and pith size. Some diagnostic characters found are presence of aquiferous parenchyma and absence of vascular bundle sheath extensions in leaves of P. urbanianus; vascular bundles decreasing in size towards the margin of leaves and bracts, and scapes with a triangular contour in P. flaccidus; scapes with nine ribs in P. acanthophyllus and ten in P. macer. All anatomical features are summarized in tables. These results aid in the identification and characterization of the species of P. sect. Diphyomene. They also support the current section circumscription, reinforcing the relevance of the anatomical characters in order to define natural groups.

Development of Contour Size Detection System of Driver Airbag

A new detection system has been designed and developed for detecting the contour size of automobile driver airbag. The detection system is mainly composed of a CCD camera, optical system and a computer which can implement image processing and image recognition. This system uses a CCD sensor as its sensitive element, as well as the basic principle of image processing combined with image segmentation and template matching to determine whether the contour size of airbag is qualified. The experimental results show that the system improves the detecting precision, and speed of assembling automobile airbags. It also solves the problems of a heavy workload by manual operations, inaccurate judgments and low efficiency.

The Contour Size Detection of Driver Airbag Based on Image Processing Technology

In this paper we have developed a new methodology for detecting the contour size of driver airbag based on image processing technology and Machine vision. Through the CCD camera we can obtain the image, and then do the following operations by a computer, such as binarization, edge extraction and so on the other image preprocessing. This methodology uses intelligent template matching technology to detect the airbags and by comparing with the predefined parameter to determine whether the contour size is qualified .The experimental results show that: this new detection method solves the disadvantage of traditional detection method, such as the low detection efficiency, the detection precision is not high, the poor detection repeatability, the higher rate of detection miscarriage of justice.

Ultrasonography and Duplex Doppler Ultrasonography Based Indices in Nodular Thyroid Disease

Background. Fine needle aspiration biopsy (FNAB) is an important tool in the diagnosis of thyroid nodules. Aim. Our aim was to investigate the malignancy criteria in thyroid nodules by gray-scale ultrasonography (US) and duplex Doppler ultrasonography (DDUS), and their usefulness in reducing the number of unnecessary FNAB’s. Study design. This was a prospective observational study. Subjects and methods. 181 benign and 18 malignant thyroid nodules were evaluated by US and DDUS before FNAB or thyroidectomy. US was used to note size, shape, internal structure, nodule echogenicity, marginal properties, peripheral hypoechogenic halo, and microcalcifications. DDUS studies were used to evaluate the maximum and minimum flow velocity (V max and V min ), systolic/diastolic flow velocity ratio (S/D), pulsatility index (PI), resistive index (RI), acceleration time (AT) and acceleration value. Results. Contour irregularity, size and presence of microcalcifications (p<0.001, p=0.02 and p=0.002, respectively) and S/D, V min , PI, RI and AT were significantly different (p=0.004, p=0.007, p=0.032, p=0.003 and p=0.003, respectively) were significant for malignant nodules. Benign and malignant nodules with or without suspicious US findings had similar DDUS findings. V max , V min , PI, RI, and AT were significantly different in the presence of microcalcification (p=0.043, p=0.001, p=0.031, p=0.04, and p=0.019 respectively). AT was significantly different in the case of absence of microcalcification (p=0.019). Comparing the irregular margins, V min , PI and RI were significantly different (p=0.014, p=0.003, and p=0.014 respectively). Conclusion. Benign and malignant thyroid nodules can be differentiated using gray-scale US findings and DDUS based indices together to reduce the number of unnecessary FNAB’s.

Information‐theoretic model selection affects home‐range estimation and habitat preference inference: a case study of male Reeves’s Pheasants Syrmaticus reevesii

Reeves’s Pheasant Syrmaticus reevesii is a vulnerable forest bird inhabiting broadleaved habitats dominated by oaks Quercus spp. in central China. Identifying home‐ranges and habitat associations is important for understanding the biology of this species and developing effective management and conservation plans. We used information‐theoretic criteria to evaluate the relative performance of four parametric (exponential power, one‐mode bivariate normal, two‐mode bivariate normal and two‐mode bivariate circle) and two non‐parametric models (adaptive and fixed kernel) for estimating home‐ranges and habitat associations of Reeves’s Pheasants. For parametric models, Akaike’s information criterion (AICc) and the likelihood cross‐validation criterion (CVC) were relatively consistent in ranking the bivariate exponential power model the least acceptable, whereas the two‐mode bivariate models performed better. The CVC suggested that kernel models, particularly the adaptive kernel, performed best among all six models evaluated. The average core area and 95% contour area based on the model with greatest support were 6.1 and 54.9 ha, respectively, and were larger than those estimated from other models. The discrepancy in estimates between models with highest and the lowest support decreased as the contour size increased; however, home‐range shapes differed between models. Minimum convex polygons that removed 5% of extreme data points (MCP95) were roughly half the size of home‐ranges based on kernel models. Estimates of home‐range and model evaluation were not affected by sample size (&gt; 50 observations for each bird). Inference about habitat preference based on composition analysis and home‐range overlap varied between models. That with strongest support suggested that Reeves’s Pheasants selected mature fir and mixed forest, avoided farmland, and had mean among‐individual home‐range overlaps of 20%. We recommend non‐parametric methods, particularly the adaptive kernel method, for estimating home‐ranges and core areas for species with complex multi‐polar habitat preferences in heterogeneous environments with large habitat patches. However, we caution against the traditional convenience of using a single model to estimate home‐ranges and recommend exploration of multiple models for describing and understanding the ecological processes underlying space use and habitat associations.

Formation of Complexes between Nanoparticles and Weak Polyampholyte Chains. Monte Carlo Simulations

The electrostatic driven complex formation between a weak polyampholyte chain and one positively charged nanoparticle is investigated using Monte Carlo simulations. The influence of parameters such as the polyampholyte contour length, number and size of blocks, nanoparticle surface charge density, and solution properties, such as the pH and ionic concentration, on the PA titration curves is investigated. It is shown that the presence of one positively charged nanoparticle significantly modifies the acid/base properties of the weak polyampholyte by, on the one hand, promoting the formation of negatively charged monomers and, on the other hand, limiting the number of positively charged monomers. The electrostatic interactions of this system can be modified by pH, ionic concentration, and nanoparticle surface charge. The competition between attractive and repulsive, intramolecular and intermolecular electrostatic interactions leads to a wide range of possible PA conformations at the nanoparticle surface, which have a direct impact on the nanoparticle stabilized or destabilized solutions. Extended conformations, electrostatic rosettes, and dense multiplayer structures are observed. Nonetheless, the intramolecular interactions between the positively and negatively charged PA monomers, in particular at the isoelectric point, are found to play important and subtle roles for both the isolated and adsorbed chain conformations. It is also found that nanoparticle charge inversion is an important ingredient for the formation of multilayer structures at the nanoparticle surface.

SU‐GG‐J‐33: Localizing a Moving Tumor Using MV‐CBCT

Purpose: To evaluate mega‐voltage cone‐beam computed tomography (MV‐CBCT) imaging of moving tumors. Method and Materials: Five patients treated for early stage non‐small cell lung cancer using stereotactic body radiation therapy (SBRT) were analyzed. Simulation images were obtained with a Siemens Sensation Open 4D‐CT scanner. The Internal Target Volume (ITV) comprised of the tumor in each phase and on the free‐breathing CT was created. Daily localization was performed with MV‐CBCT on a Siemens Artiste linear accelerator with the in‐line kView system, using a 4.2 MeV electron beam incident on a carbon target without flattening filter to increase the yield of low energy photons. The tumor was contoured on each daily CB image. The size of the ITV contours on the planning CT and MV‐CBCT was compared in the anterior‐posterior (AP), left‐right (LR) and superior‐inferior (SI) directions. Results: In the majority of cases the standard deviation of the MV‐CBCT contour size from day to day was less than 2 mm. The average difference between the planning CT and MV‐CBCT contours varies widely from patient to patient. The largest difference (10.1 mm) was seen in the SI direction for a patient for whom breathing motion was large (18 mm), and the contrast between the tumor and its surroundings in the expected tumor position during the full‐inhale phase was reduced. The second largest difference (7.2 mm) was seen in the SI direction in a patient for whom the proximity of the tumor to a large blood vessel also reduced the contrast. Conclusion: There is a possibility of inaccurate registration between the planning CT and MV‐CBCT and less effective localization when the contrast is adversely affected because of large tumor motion or proximity to other structures. This should be taken into account in the Planning Target Volume margin. Research partially supported by Siemens Medical Solutions.

Real-Time Lane and Vehicle Detection Based on A Single Camera Model

This paper presents a real-time lane detection algorithm and a fuzzy-based vehicle detection approach for autonomous vehicles. The fast adaptive lane detection algorithm is efficient and robust during the day and at night. Modified global lane models are proposed to increase the accuracy of the detection. Moreover, an automatic adjustment method is presented to adapt to the changes of lane width and the inclination of roads in different situations. The developed fuzzy-based vehicle detection method, contour size similarity (CSS), compares the projective sizes of vehicles with the estimated ones by fuzzy logic. Vehicle detection aims to detect the closest vehicle preceding the autonomous car in the same lane. Results of the experiments demonstrate that the proposed approach is effective in distance estimation and both lane and vehicle detection. Furthermore, the approach rapidly adjusts to changes of detection target when another car cuts in the lane of the autonomous vehicle.The obtained information supports the automatic driving of autonomous vehicles. This integrated algorithm of lane and vehicle detection was verified on the autonomous car, TAIWAN iTS-1, on express highways and in urban environments at velocities of 110 and 50 km/h , respectively.

Constant contour integration in peripheral vision for stimuli with good Gestalt properties

The visual system integrates discrete but aligned local stimuli to form percept of global contours. Previous experiments using "snake" contours showed that contour integration was mainly present in foveal vision but absent or greatly weakened in peripheral vision. In this study, we demonstrated that, for contour stimuli such as circles and ellipses, which bore good Gestalt properties, contour integration for shape detection and discrimination was nearly constant from the fovea to up to 35 degrees visual periphery! Contour integration was impaired by local orientation and position jitters of contour elements, indicating that the same local contour linking mechanisms revealed with snake contour stimuli also played critical roles in integration of our good Gestalt stimuli. Contour integration was also unaffected by global position jittering up to 20% of the contour size and by dramatic shape jittering, which excluded non-contour integration processes such as detection of various local cues and template matching as alternative mechanisms for uncompromised peripheral perception of good Gestalt stimuli. Peripheral contour integration also presented an interesting upper-lower visual field symmetry after asymmetries of contrast sensitivity and shape discrimination were discounted. The constant peripheral performance might benefit from easy detection of good Gestalt stimuli, which popped out from background noise, from a boost of local contour linking by top-down influences and/or from multielement contour linking by long-range interactions.

Sound processing in amateur musicians and nonmusicians: event-related potential and behavioral indices

To increase our understanding of auditory neurocognition in musicians, we compared nonmusicians with amateur band musicians in their neural and behavioral sound encoding accuracy. Mismatch negativity and P3a components of the auditory event-related potentials were recorded to changes in basic acoustic features (frequency, duration, location, intensity, gap) and abstract features (melodic contour and interval size). Mismatch negativity was larger in musicians than in nonmusicians for location changes whereas no statistically significant group difference was observed in response to other feature changes or in abstract-feature mismatch negativity. P3a was observed only in musicians in response to location changes. This suggests that when compared with nonmusicians, even amateur musicians have neural sound processing advantages with acoustic information most essential to their musical genre.

MR imaging of thymic epithelial tumors: correlation with World Health Organization classification

The aim of this study was to determine magnetic resonance imaging (MRI) features of various subtypes of thymic epithelial tumors based on the World Health Organization classification. The study included 64 patients with histologically proven thymic epithelial tumors. Two observers evaluated the MRI findings in terms of tumor size, contour, lobulation, shape, homogeneity, the presence of intratumor high- and low-signal foci, enhancement degree and pattern, the presence of capsule and septum, and associated mediastinal lymphadenopathy and pleural effusion. Type A tumors were more likely to have a smooth contour, round shape, distinct capsule, and smaller size compared to any other type of thymic epithelial tumor. Thymic carcinomas demonstrated a higher prevalence of low-signal foci within the mass on T2-weighted images and mediastinal lymphadenopathy than any other types. The frequency of heterogeneous intensity on T2-weighted images increased from type A tumors to thymic carcinomas. The presence of a smooth contour, round shape, and capsule is highly suggestive of a type A tumor. Foci of low signal intensity in the mass on T2-weighted images and mediastinal lymphadenopathy are highly suggestive of thymic carcinomas.

Sequence Structure of van der Waals Locks in Proteins

Recent works has suggested that proteins in early evolution have gone through a stage of closed loop elements with a typical contour size of 25–35 residues. These closed loops are still the elementary protein units to these days, and can be used to spell out protein sequence/structure relationship through a relatively small number of protein prototypes. In this study we aimed to identify the sequences that are used to lock the loop ends to one another, and to show how an extensive dictionary of such locking pairs can be created using positional correlation data from a large proteome database, and structural data from PDB databases. Such a dictionary can be used in reconstructing the evolutionary pathway the modern proteins have gone through, and in identifying closed loop elements in modern proteins with yet unknown 3D structure.

Face processing in humans is compatible with a simple shape–based model of vision

Understanding how the human visual system recognizes objects is one of the key challenges in neuroscience. Inspired by a large body of physiological evidence, a general class of recognition models has emerged, which is based on a hierarchical organization of visual processing, with succeeding stages being sensitive to image features of increasing complexity. However, these models appear to be incompatible with some well-known psychophysical results. Prominent among these are experiments investigating recognition impairments caused by vertical inversion of images, especially those of faces. It has been reported that faces that differ 'featurally' are much easier to distinguish when inverted than those that differ 'configurally'; a finding that is difficult to reconcile with the physiological models. Here, we show that after controlling for subjects' expectations, there is no difference between 'featurally' and 'configurally' transformed faces in terms of inversion effect. This result reinforces the plausibility of simple hierarchical models of object representation and recognition in the cortex.

Length illusions and attentional deployment

Length illusions are caused by the systematic manipulation of size ratios. The principle of relational determination (i.e., framing ratio) holds for different classical illusional displays and is described as a failure of selective attention that facilitates size constancy. Implementing a spatial distance (D) between the focal stimulus (of length F) and the contour marks (of length B) leads to illusions that contradict the description in terms of a simple framing ratio. The stimulus configuration rather than the framing ratio determines the illusions (two different ratios are independently effective, D/F and B/F). The relational determination of length illusions contradicts explanations in terms of either efferent readiness or attentional deployment. In a developmental approach, it was shown that a failure of selective attention to the length of the focal stimulus due to relational determination holds only for adults (aged 21–32 years). The B/F ratio tended to effectiveness in determining the illusions for children aged 7–9 years, but not for children aged 5–6 years. The absolute size of D, regardless of F, determined the illusional trends of both groups of children. The failure of selective attention, which facilitates size constancy, in judging length illusions seems to develop first for contour size and later for spatial distance.

Analysis for the validity of the J-integral for media with voids

It has been shown that for media with voids, the J-integral depends on the integration contour size. To calculate the J-integral for media with voids, a procedure has been proposed for which the J-integral is independent of the integration contour size. The J-integral as calculated by the proposed procedure is denoted as the J s -integral. Constitutive equations for media with voids have been formulated on the basis of an effective stress, as proposed by Kachanov. It has been shown that the J s -integral is independent of the integration contour size both for constitutive equations proposed by the authors and for other constitutive equations, i.e. the models of Gurson and Rousselier. To verify the proposed formulation for the J s -integral, a numerical investigation for media with voids has been performed.