Large Shape Variations Research Articles

1310 数値シミュレーションを活用した超微細粒棒鋼創成における圧延パスの最適化(OS7-3 設計と最適化III-衝撃・加工-,OS7 設計と最適化)

The caliber configuration design for creating ultrafine-grained steel bars through a groove rolling process was studied from the viewpoint of a large strain accumulation and cross-sectional shape variation in a bar. A three-dimensional finite element analysis was employed for this purpose. The square/foval (flat-like-oval)/square rolling was proposed as a method to introduce a large strain efficiently in material. The relation among the foval configuration, a strain and cross-sectional shape was examined in the groove rolling. The influence of the equivalent strain distribution by 1st pass (foval rolling) was considered to clarify the strain distribution and a cross-sectional shape by 2nd pass, and then the foval configuration to accumulate a large strain efficiently was shown. The optimum pass schedule to fabricate an ultrafine-grained steel of 13mm square bar from a 24mm square bar was proposed in warm groove rolling.

Estimating population age structure using otolith morphometrics: a test with known-age Atlantic cod (Gadus morhua) individuals

Traditional age reading is a rather subjective method that lacks true reproducibility, producing ageing error that propagates up to stock assessment. One alternative is represented by the use of otolith morphometrics as a predictor of age. An important issue with such a method is that it requires known-age fish individuals. Here we used known-age Atlantic cod ( Gadus morhua ) from the Faroe Bank and Faroe Plateau stocks. Cod populations usually show quite large variation in growth rates and otolith shape. We showed that including otolith morphometrics into ageing processes has the potential to make ageing objective, accurate, and fast. Calibration analysis indicated that a known-age sample from the same population and environment is needed to obtain robust calibration; using a sample from a different stock more than doubles the error rate, even in the case of genetically highly related populations. The intercalibration method was successful but generalization from one stock to another remains problematic. The development of an otolith growth model is needed for generalization if an operational method for different populations is required in the future.

Simultaneous Segmentation of Bladder and Prostate using Globally Optimal 3-D Graph Search Method

Precise target delineation is critically important for a successful conformal radiotherapy treatment planning. The segmentation of pelvic structure is a particularly difficult task since it involves soft tissues that present a large variability in shape and size and also have serious mutual influence in position and shape between each other. We propose a novel method for simultaneous segmentation of bladder and prostate using a 3-D graph-theoretic approach. The algorithm computes a global optimum of an objective function controlled by the cost function designed for each boundary surface.

Fluorescence Excitation and Emission Spectroscopy on Single MEH-PPV Chains at Low Temperature

Fluorescence emission and excitation spectra of single MEH-PPV polymer molecules dispersed in thin PMMA films have been recorded at 1.2 and 20 K. We observe single as well as multichromophore emission in single chain emission spectra, whereby the relative fractions depend on the two different molecular weights (50 and 350 kDa) studied. The molecular weight also affects the distribution of peak emission maxima, which is monomodal (bimodal) for the low (high) molecular weight. The appearance of an additional "red" subpopulation for the high molecular weight sample is attributed to interactions of multiple chromophores from a sufficiently flexible single chain. The comparison of emission spectra appearing in the "blue" as well as "red" subpopulations suggests that these intrachain interactions rather lead to ground-state aggregates than excimers. Independent of the molecular weight, large variations in spectral shape and apparent line width in the emission spectra have been observed. Occasionally, we find very narrow purely electronic zero-phonon lines both in emission and in excitation spectra, with line widths down to the instrumental resolution. In accordance with earlier literature data it is argued that linear electron-phonon coupling should be quite strong for MEH-PPV in PMMA, leading to only a small fraction of chromophores exhibiting zero-phonon lines. In addition, spectral diffusion, which manifests itself by several time-dependent line shifting and broadening phenomena, contributes to the substantial variations of spectral shapes. Excitation experiments with particularly stable chromophores provide an upper limit for the optical line width (approximately 0.1 cm(-1)), which at 1.2 K can actually approach the lifetime-limited homogeneous width. Raising the temperature to 20 K leads to line broadening and typically, to disappearance of zero-phonon lines. The failure to observe zero-phonon lines of chromophores supposedly serving as donors in intramolecular energy transfer is tentatively attributed to fast transfer rates, resulting in strongly broadened lines which escape detection even at 1.2 K.

Complex behavioural pattern as an aid to identify the producer ofZoophycosfrom the Middle Permian of Oman

The trace fossil Zoophycos is abundant in transgressive, shallow marine carbonates in the Middle Permian (Wordian) Khuff Formation of the Huqf-Haushi Uplift of Interior Oman. It often occurs as part of a complex (compound) trace fossil that comprises two integrated elements: (i) irregular galleries with straight to gently curved tunnels and interconnected shafts, and (ii) simple planar to complex spreiten structures with a marginal tube (Zoophycos). The galleries are characterized by irregularly winding, dichotomous branching, large variation in shape and size and circular to elliptical vertical cross-sections. Zoophycos consists of spreiten with a marginal tube, either originating as a simple lobe from the convex segment of a curved tunnel, or forming more complex, subcircular, spreiten systems parallel to bedding. The spreiten were formed by simple strip mining, where the animal defecated without producing faecal pellets. U-shaped marginal tubes indicate that the burrows were well aerated. The complex trace fossil points to combined dwelling and deposit-feeding behaviour, with irregular galleries in the firm substrate and Zoophycos spreiten in the softground below it. It can be assumed that the animal used the open tunnel system mainly for dwelling (domichnion) and possibly suspension feeding, but occasionally changed to deposit feeding while creating the spreiten (fodinichnion). The integration of the irregular galleries (tunnels and interconnected shafts) with the marginal tubes of Zoophycos suggests the same producer for this compound trace fossil. Many modern polychaetes produce very similar galleries within firm and soft substrates, and polychaetes are therefore interpreted as the most likely producers. Similarities between Permian and Triassic Zoophycos suggest comparable trace making behaviour before and after the end-Permian mass extinction.

Deformation‐Driven Shape Correspondence

AbstractNon‐rigid 3D shape correspondence is a fundamental and difficult problem. Most applications which require a correspondence rely on manually selected markers. Without user assistance, the performances of existing automatic correspondence methods depend strongly on a good initial shape alignment or shape prior, and they generally do not tolerate large shape variations. We present an automatic feature correspondence algorithm capable of handling large, non‐rigid shape variations, as well as partial matching. This is made possible by leveraging the power of state‐of‐the‐art mesh deformation techniques and relying on a combinatorial tree traversal for correspondence search. The search is deformation‐driven, prioritized by a self‐distortion energy measured on meshes deformed according to a given correspondence. We demonstrate the ability of our approach to naturally match shapes which differ in pose, local scale, part decomposition, and geometric detail through numerous examples.

WE-D-351-07: Daily CT Guidance in Liver Stereotactic Body Radiation Therapy; Impact of a Non-Rigid Patient Anatomy On OAR Dose

Purpose: To investigate the influence of daily tumor‐based setup corrections, derived from pre‐treatment CT‐scans, on the organs‐at‐risk (OARs) dose distributions in stereotactic body radiation therapy(SBRT) of livertumors.Method and Materials: Fifteen patients diagnosed with liver metastases and treated with SBRT were included in this study. Patients were positioned in a stereotactic body frame and abdominal compression was applied to decrease the respiratory tumor displacement. A total dose of 37.5 Gy at the 65% isodose was delivered in three fractions. Sixty CT data sets, corresponding to the planning and consecutive treatment days, were reviewed. Relevant OARs were delineated on all CT sets. Daily 3D dose distributions were calculated using the daily CT sets, both without and with taking the clinically applied setup correction into account. Dose‐volume histograms and relevant dosimetric parameters for the PTV and all OARs were calculated. Results: Large shape and volume variations were seen for OARs (especially the oesophagus, duodenum and stomach), causing large variations in the dose to these organs. In 27% of the treatment fractions, it was seen that after setup correction the dose to an OAR exceeded the constraints, while the planning was within constraints; in one case, the constraint was exceeded by a factor of two. Setup correction yielded a significant increase in PTV coverage, but for the OARs no significant dosimetric effect was seen. Conclusion: Daily tumor‐based CT‐guidance is effective to increase PTV coverage, but does not significantly affect dose to the OARs. This is due to their non‐rigid motion and volume variations. Both may cause substantial OAR constraint violations, even after set‐up correction. However, for most fractions the dose to the OARs is within constraints. To obtain optimal sparing of OARs, adaptive treatment explicitly accounting for non‐rigid anatomy may be required, especially when the tumordose is escalated.

TH‐C‐350‐02: Is Dose Rate Variation Crucial for Single‐Arc Radiation Therapy Delivery?

Purpose: Recent arc therapy techniques such as arc‐modulated radiation therapy (AMRT) developed at the University of Maryland and Varian's RapidArc™ allow variable segment‐weightings in order to expand the optimization domain. As a result, these plans may require a varying dose rate (DR) for delivery. To evaluate the necessity of DR variation in arc therapy delivery, the variable‐DR plans were translated in such a way that they can be delivered with a constant DR. Method and Materials: Four cases were selected for this study: 1 HN, 1 lung, 1 prostate and 1 brain. A single‐arc AMRT plan was generated for each case. Planning of AMRT started with optimization of ideal intensity maps with 36 equi‐spaced beams in Pinnacle followed by segmentation of the intensity maps into a deliverable AMRT MLC sequence. During leaf‐sequencing, the segment weightings are allowed to vary. In translating variable‐DR AMRT plans into constant‐DR plans, the angular spacing of the original beams were changed from equi‐spacing to spacing according to their weightings. Hence, apertures with more MUs occupy a greater angular range. To account for any field shifting in the process, a field shape correction was applied ensuring proper target coverage. Results and Conclusion: DVH comparisons show that constant‐DR plans were comparable to the corresponding variable‐DR plans in 3 of the 4 cases. Significant degradation occurred in the constant‐DR plan of the prostate case due to the large MU variations in the original variable‐DR plan, causing the beams to deviate significantly from their original positions. The estimated delivery times of the constant‐DR plans are 3 to 30 times longer than the variable‐DR plans due to large MLC shape variation within a small beam interval. It is hereby shown that DR variation is crucial to AMRT delivery in order to maintain excellent plan quality and efficient delivery time.

実機溝ロール圧延機による超微細粒組織棒鋼の創成

A caliber-rolling process with new type groove characterized by multidirectional deformation was proposed to fabricate ultrafine-grained (UFG) steel bars efficiently. To impose a large strain into center of cross-section, the groove configuration of foval (flat-like-oval) type was designed. Three-dimensional finite element simulation (FE simulation) was utilized for this purpose, and the caliber-rolling process of square/foval pass was investigated from the viewpoints of a large strain accumulation and cross-sectional shape variation in a bar. The UFG steel bars were fabricated by using the commercial caliber-rolling with the grooves designed from FE simulation. The cross-sectional shape predicted from FE simulation was in excellent agreement with the shape of the rolled bars. The strain imposed in the rolled bars has a distribution with maximum at the center. The giant strain of 5.2 is accumulative in center regardless of reduction in area of 79%. The good correlation between the strain imposed and the hardness of the rolled bars was confirmed.

Observation of Very Narrow Linewidths in the Fluorescence Excitation Spectra of Single Conjugated Polymer Chains at 1.2 K

Fluorescence emission and excitation spectra of single poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] polymer molecules embedded in poly(methylmethacrylate) have been recorded at 1.2 K. The ubiquitous spectral diffusion causes large variations in the spectral shape and apparent linewidth in the emission spectra. Nevertheless, we find very narrow (approximately 0.1 cm(-1)) purely electronic zero-phonon lines in the excitation spectra, which are 2 orders of magnitude smaller than previous estimates of the homogeneous linewidth. These results complement the molecular description of the low energy transitions in conjugated polymers.

A Survey Study on the Distribution of Saudi Baladi Chickens and Their Characteristics

Two surveys were conducted to determine the distribution and Characteristics of the local (baladi) chickens of Saudi Arabia. The results of the two surveys provided evidence that: 1. Local chickens exhibit large variations in body shape, feather color, comb type and shank color. They are small in size. 2. Most of the large baladi project (>1000 layers) were found in Makkah, Jedda and Madina. Medium size farms (250 - 600 hens) were found in Qasim, Madina, Makkah, Durma and Qatif. Smaller size farms (< 250 hens) were found in Makkah, Qasim and Hofuf. 3. Twenty three % of the large baladi projects were Poultry producers raising chicks as the main source of their income. 4. Eighty % of the small projects raise the baladi chickens along with other animals. 5. Average flock size of the large farms was 3479 birds. 6. Average marketing age of the birds were 14.6 weeks. 7. Baladi hens lay their 1 egg at 22.76 week of age and continue laying for st 78.9 weeks producing 170 eggs. 8. Nine % of the large projects' owners found that New Castle disease (ND) was the most frequent occurring disease. All chickens owners vaccinate their birds against ND while 33 % vaccinate against Fowl pox. 9. About 80 % of small farms owners are making use of the broodiness phenomena to hatch eggs while only 8 % use small incubators for that purpose.

3D free-form object recognition in range images using local surface patches

This paper introduces an integrated local surface descriptor for surface representation and 3D object recognition. A local surface descriptor is characterized by its centroid, its local surface type and a 2D histogram. The 2D histogram shows the frequency of occurrence of shape index values vs. the angles between the normal of reference feature point and that of its neighbors. Instead of calculating local surface descriptors for all the 3D surface points, they are calculated only for feature points that are in areas with large shape variation. In order to speed up the retrieval of surface descriptors and to deal with a large set of objects, the local surface patches of models are indexed into a hash table. Given a set of test local surface patches, votes are cast for models containing similar surface descriptors. Based on potential corresponding local surface patches candidate models are hypothesized. Verification is performed by running the Iterative Closest Point (ICP) algorithm to align models with the test data for the most likely models occurring in a scene. Experimental results with real range data are presented to demonstrate and compare the effectiveness and efficiency of the proposed approach with the spin image and the spherical spin image representations.

Macromolecular transport in heart valves. II. Theoretical models

This paper proposes a new, two-dimensional convection-diffusion model for macromolecular transport in heart valves based on horseradish peroxidase (HRP) experiments on rats presented in the first of the papers in this series (Part I; Zeng Z, Yin Y, Huang AL, Jan KM, Rumschitzki DS. Am J Physiol Heart Circ Physiol 292: H2664-H2670, 2007). Experiments require two valvular intimae, one underneath each endothelium. Tompkins et al. (Tompkins RG, Schnitzer JJ, Yarmush ML. Circ Res 64: 1213-1223, 1989) found large variations in shape and magnitude in transvalvular (125)I-labeled low-density lipoprotein (LDL) profiles from identical experiments on four squirrel monkeys. Their one-dimensional, uniform-medium diffusion-only model fit three parameters independently for each profile; data variability resulted in large parameter spreads. Our theory aims to explain their data with one parameter set. It uses measured parameters and some aortic values but fits the endothelial mass transfer coefficient (k(a)=k(v)=1.63 x 10(-8) cm/s, where subscripts a and v indicate aortic aspect and ventricular aspect, respectively) and middle layer permeability (K(p(2))=2.28 x 10(-16)cm(2)) and LDL diffusion coefficient [D(2)(LDL)=5.93 x 10(-9) cm(2)/s], using one of Tompkins et al.'s profiles, and fixes them throughout. It accurately predicts Part I's rapid localized HRP leakage spot growth rate in rat leaflets that results from the intima's much sparser structure, dictating its far larger transport parameters [K(p(1))= 1.10 x 10(-12)cm(2), D(1)(LDL/HRP)=1.02/4.09 x 10(-7)cm(2)/s] than the middle layer. This contrasts with large arteries with similarly large HRP spots, since the valve has no internal elastic lamina. The model quantitatively explains all of Tompkins et al.'s monkey profiles with these same parameters. Different numbers and locations of isolated macromolecular leaks on both aspects and different section-leak(s) distances yield all profiles.

A field model for human detection and tracking

The large shape variability and partial occlusions challenge most object detection and tracking methods for nonrigid targets such as pedestrians. This paper presents a new approach based on a two-layer statistical field model that characterizes the prior of the complex shape variations as a Boltzmann distribution and embeds this prior and the complex image likelihood into a Markov field. A probabilistic variational analysis of this model reveals a set of fixed-point equations characterizing the equilibrium of the field. It leads to computationally efficient methods for calculating the image likelihood and for training the model. Based on that, effective algorithms for detecting nonrigid objects are developed. This new approach has several advantages. First, it is intrinsically suitable for capturing local nonrigidity. In addition, due to the distributed likelihood, this approach is robust to partial occlusions. Moreover, the two-layer structure provides large flexibility of modeling the image observations, which makes the new method robust to clutters. Extensive experiments demonstrate its effectiveness.

Functional and Structural Characterization of Rhodopsin Oligomers

A major question in G protein-coupled receptor signaling concerns the quaternary structure required for signal transduction. Do these transmembrane receptors function as monomers, dimers, or larger oligomers? We have investigated the oligomeric state of the model G protein-coupled receptor rhodopsin (Rho), which absorbs light and initiates a phototransduction-signaling cascade that forms the basis of vision. In this study, different forms of Rho were isolated using gel filtration techniques in mild detergents, including n-dodecyl-beta-D-maltoside, n-tetradecyl-beta-D-maltoside, and n-hexadecyl-beta-D-maltoside. The quaternary structure of isolated Rho was determined by transmission electron microscopy, demonstrating that in micelles containing n-dodecyl-beta-D-maltoside, Rho exists as a mixture of monomers and dimers whereas in n-tetradecyl-beta-D-maltoside and n-hexadecyl-beta-D-maltoside Rho forms higher ordered structures. Especially in n-hexadecyl-beta-D-maltoside, most of the particles are present in tightly packed rows of dimers. The oligomerization of Rho seems to be important for interaction with its cognate G protein, transducin. Although the activated Rho (Meta II) monomer or dimers are capable of activating the G protein, transducin, the activation process is much faster when Rho exists as organized dimers. Our studies provide direct comparisons between signaling properties of Meta II in different quaternary complexes.

History of the Crested Lark in the Mediterranean region as revealed by mtDNA sequences and morphology

The Crested Lark has a very complex taxonomy, partly as a result of a strong variation in plumage ground color seemingly linked with environmental factors. However, large variations in body size and bill shape further complicate the situation in the Maghreb. In this paper, we first present a set of hypotheses to explain patterns of morphological variation around the Mediterranean Sea. A phylogeographical analysis covering all major biogeographical areas in the species’ range is then performed to test these scenarios. Three mtDNA groups with distinct geographical distribution were identified. The randonii clade (= G. (c.) randonii) is endemic from central Maghreb and is phylogenetically basal relative to cristata and senegallensis. These two latter groups are much more widespread. The cristata clade is found in NW Morocco, throughout Europe and W Asia and in NE Africa, while senegallensis regroups the populations sampled in the Western Sub-Saharan Africa and in NE Maghreb (E Algeria, Tunisia). A combination of genetic and paleoenvironmental evidences supports a scenario of allopatric differentiation of these two lineages outside the Maghreb, with subsequent range expansion leading to their secondary presence in the Maghreb. However, the alternative hypothesis of differentiation in two, or even three separate Maghreb refuges cannot be completely dismissed with the present data. Interestingly, the Sahara desert and the Gibraltar Strait did not act as permanent barriers to dispersal in this species. In addition, the populations in the Maghreb are consistently longer-billed than their closest relatives, suggesting a role for natural selection or phenotypic plasticity.

The human eye is an example of robust optical design

In most eyes, in the fovea and at best focus, the resolution capabilities of the eye's optics and the retinal mosaic are remarkably well adapted. Although there is a large individual variability, the average magnitude of the high order aberrations is similar in groups of eyes with different refractive errors. This is surprising because these eyes are comparatively different in shape: Myopic eyes are longer whereas hyperopic eyes are shorter. In most young eyes, the amount of aberrations for the isolated cornea is larger than for the complete eye, indicating that the internal ocular optics (mainly the crystalline lens) play a significant role in compensating for the corneal aberrations, thereby producing an improved retinal image. In this paper, we show that this compensation is larger in the less optically centered eyes that mostly correspond to hyperopic eyes. This suggests a type of mechanism in the eye's design that is the most likely responsible for this compensation. Spherical aberration of the cornea is partially compensated by that of the lens in most eyes. Lateral coma is also compensated mainly in hyperopic eyes. We found that the distribution of aberrations between the cornea and lens appears to allow the optical properties of the eye to be relatively insensitive to variations arising from eye growth or exact centration and alignment of the eye's optics relative to the fovea. These results may suggest the presence of an auto-compensation mechanism that renders the eye's optics robust despite large variation in the ocular shape and geometry.

The grapevine fleshless berry mutation. A unique genotype to investigate differences between fleshy and nonfleshy fruit.

In flowering plants, fruit morphogenesis is a distinct process following fertilization resulting in the formation of a specialized organ associated with seeds. Despite large variations in types and shapes among species, fleshy fruits share common characteristics to promote seed dispersal by animals such as organ growth and metabolite accumulation to attract animal feeding. The molecular biology of fruit ripening has received considerable attention, but little is known about the determinism of early fruit morphogenesis and why some fruits are fleshy while others lack flesh. We have identified in grapevine (Vitis vinifera) a mutation we have named fleshless berry (flb) that reduces by 20 times the weight of the pericarp at ripening without any effect on fertility or seed size and number. The flb mutation strongly impaired division and differentiation of the most vacuolated cells in the inner mesocarp. The timing of ripening was not altered by the mutation although the accumulation of malic acid in the green stage was noticeably reduced while sucrose content (instead of hexoses) increased during ripening. The mutation segregates as a single dominant locus. These results indicate that the Flb- mutant is suitable material to advance our understanding of the genetic and developmental processes involved in the differentiation of an ovary into a fruit.

数値解析による超微細組織棒鋼創製のための高効率加工プロセスの提案

The caliber configuration design for creating ultrafine-grained steel bars through groove rolling is studied from the viewpoint of a large strain accumulation and cross-sectional shape variation in a bar. A three-dimensional explicit finite element analysis is employed for this purpose. The square-foval (flat-like-oval)-square rolling method is proposed to introduce a large strain in material. The relation between the foval configuration, a strain and cross-sectional shape is examined in the groove rolling. The influence of the equivalent strain distribution by 1st pass (foval rolling) is considered to clarify the strain distribution and a cross-sectional shape by 2nd pass, and then the foval configuration to accumulate a large strain efficiently is shown. The pass schedule to fabricate an ultrafine-grained steel of 13 mm square bar from a 24 mm square bar is proposed in warm groove rolling.

On-line cursive hangul recognition that uses DP matching to detect key segmentation points

As a means to perform on-line recognition of cursive Korean characters, called hanguls, we describe a structural analysis type algorithm that searches globally for key points of segmentation on a character unit level and can cope with large variations in stroke shape and position. This “segmentation points search” is systematically performed by a two-level dynamic programming (DP) matching algorithm in conjunction with syntax control of hangul composition characteristics. Fine discrimination for phonemes and characters is effectively realized using mutual information among strokes. Experiments demonstrate computational feasibility and that the proposed approach provides high recognition and segmentation ability.