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Outlier/Noise-Robust Partition of Unity Implicit Surface Reconstruction
Yukie Nagai,Yutaka Ohtake,Hiromasa Suzuki,Hideo Yokota (사)한국CDE학회 2010 한국CAD/CAM학회 국제학술발표 논문집 Vol.2010 No.8
In this paper, we propose an algorithm for outlier/noise-robust surface reconstruction based on a partition of unity (PU) approach. PU based surface reconstruction is a local method that covers an area including sampling points with spherical supports of local approximations, and then generates an approximation function whose zero-level sets approximate the surface. This algorithm has many advantages including representation of fine details, and fast and memory efficient computation. Many of these advantages are realized with the locality of PU however, it is also the reason of outlier/noise-instabilities. Unfortunately, scanned data generally contain much amount of noise, and hence improving the robustness of PU based algorithm is required. We achieve an outlier/noise-robust algorithm with integrating Graph-cut and diffusion of local approximations. Since the characteristics of outliers and noise are fundamentally different, overcoming these two with different approaches is reasonable. In our algorithm, first a spherical cover of an area containing input points is generated following the PU manner. And then Graph-cut is performed in order to determine spherical supports which are considered wrongly approximating affected by outliers. Finally, the PU approximation function is updated so that its gradient field smoothed. This smoothing is based on a diffusion of the local approximations. In this paper we show the effects of this integration approach for several scanned data sets.
Aoyama, Yuki,Toriumi, Kazuya,Mouri, Akihiro,Hattori, Tomoya,Ueda, Eriko,Shimato, Akane,Sakakibara, Nami,Soh, Yuka,Mamiya, Takayoshi,Nagai, Taku,Kim, Hyoung-Chun,Hiramatsu, Masayuki,Nabeshima, Toshitak American College of Neuropsychopharmacology 2016 Neuropsychopharmacology Vol.41 No.2
<P>Cigarette smoking during pregnancy is associated with various disabilities in the offspring such as attention deficit/hyperactivity disorder, learning disabilities, and persistent anxiety. We have reported that nicotine exposure in female mice during pregnancy, in particular from embryonic day 14 (E14) to postnatal day 0 (P0), induces long-lasting behavioral deficits in offspring. However, the mechanism by which prenatal nicotine exposure (PNE) affects neurodevelopment, resulting in behavioral deficits, has remained unclear. Here, we report that PNE disrupted the proliferation of neuronal progenitors, leading to a decrease in the progenitor pool in the ventricular and subventricular zones. In addition, using a cumulative 5-bromo-2'-deoxyuridine labeling assay, we evaluated the rate of cell cycle progression causing the impairment of neuronal progenitor proliferation, and uncovered anomalous cell cycle kinetics in mice with PNE. Accordingly, the density of glutamatergic neurons in the medial prefrontal cortex (medial PFC) was reduced, implying glutamatergic dysregulation. Mice with PNE exhibited behavioral impairments in attentional function and behavioral flexibility in adulthood, and the deficits were ameliorated by microinjection of D-cycloserine into the PFC. Collectively, our findings suggest that PNE affects the proliferation and maturation of progenitor cells to glutamatergic neuron during neurodevelopment in the medial PFC, which may be associated with cognitive deficits in the offspring.</P>
What Factors Mediate Individual Differences in Color Matching?
Atsushi Konno,Kunihiro Hatakeyama,Yuki Kawashima,Tomonori Tashiro,Takehiro Nagai,Yasuki Yamauchi 한국색채학회 2017 AIC 2017 Jeju Vol.2017 No.10
We aimed to specify physiological factors which mediate individual differences in color matching. In previous studies, we found that the deviations of the color matching for the red-green direction is correlated with the macular pigment density. However, the factors causing blue-yellow deviation were not clarified. In this study, we performed a color matching experiment using metamers with the identical tristimulus values and an identical amount of the macular pigment absorption to examine the deviations of the color matching in the blue-yellow direction. As a result, there was a correlation between color matching deviations and the amounts of light absorbed by lens for each metamer, suggesting that the deviations of color matching in blue-yellow direction may be due to the amount absorbed of lens. These results suggest that individual difference in color matching in short wavelength light is strongly mediated by these two physiological properties of the eye.
Learning for Goal-Directed Actions Using RNNPB: Developmental Change of “What to Imitate”
Park, Jun-Cheol,Kim, Dae-Shik,Nagai, Yukie IEEE 2018 IEEE transactions on cognitive and developmental s Vol.10 No.3
<P>“What to imitate” is one of the most important and difficult issues in robot imitation learning. A possible solution from an engineering approach involves focusing on the salient properties of actions. We investigate the developmental change of what to imitate in robot action learning in this paper. Our robot is equipped with a recurrent neural network with parametric bias (RNNPB), and learned to imitate multiple goal-directed actions in two different environments (i.e., simulation and real humanoid robot). Our close analysis of the error measures and the internal representation of the RNNPB revealed that actions’ most salient properties (i.e., reaching the desired end of motor trajectories) were learned first, while the less salient properties (i.e., matching the shape of motor trajectories) were learned later. Interestingly, this result was analogous to the developmental process of human infant’s action imitation. We discuss the importance of our results in terms of understanding the underlying mechanisms of human development.</P>
Flattening simulations of 3D thick sheets made of fiber composite materials
Morioka, Kotaro,Ohtake, Yutaka,Suzuki, Hiromasa,Nagai, Yukie,Hishida, Hiroyuki,Inagaki, Koichi,Nakamura, Takeshi,Watanabe, Fumiaki Society for Computational Design and Engineering 2015 Journal of computational design and engineering Vol.2 No.2
Recently, fiber composite materials have been attracting attention from industry because of their remarkable material characteristics, including light weight and high stiffness. However, the costs of products composed of fiber materials remain high because of the lack of effective manufacturing and designing technologies. To improve the relevant design technology, this paper proposes a novel simulation method for deforming fiber materials. Specifically, given a 3D model with constant thickness and known fiber orientation, the proposed method simulates the deformation of a model made of thick fiber-material. The method separates a 3D sheet model into two surfaces and then flattens these surfaces into two dimensional planes by a parameterization method with involves cross vector fields. The cross vector fields are generated by propagating the given fiber orientations specified at several important points on the 3D model. Integration of the cross vector fields gives parameterization with low-stretch and low-distortion.
3D scanning based mold correction for planar and cylindrical parts in aluminum die casting
Seno, Takashi,Ohtake, Yutaka,Kikuchi, Yuji,Saito, Noriaki,Suzuki, Hiromasa,Nagai, Yukie Society for Computational Design and Engineering 2015 Journal of computational design and engineering Vol.2 No.2
Aluminum die casting is an important manufacturing process for mechanical components. Die casting is known to be more accurate than other types of casting; however, post-machining is usually necessary to achieve the required accuracy. The goal of this investigation is to develop machining- free aluminum die casting. Improvement of the accuracy of planar and cylindrical parts is expected by correcting metal molds. In the proposed method, the shape of cast aluminum made with the initial metal molds is measured by 3D scanning. The 3D scan data includes information about deformations that occur during casting. Therefore, it is possible to estimate the deformation and correction amounts by comparing 3D scan data with product computer-aided design (CAD) data. We corrected planar and cylindrical parts of the CAD data for the mold. In addition, we corrected the planar part of the metal mold using the corrected mold data. The effectiveness of the proposed method is demonstrated by evaluating the accuracy improvement of the cast aluminum made with the corrected mold.
A system for three-dimensional gaze fixation analysis using eye tracking glasses
Ryo Takahashi,Hiromasa Suzuki,Jouh Yeong Chew,Yutaka Ohtake,Yukie Nagai,Koichi Ohtomi 한국CDE학회 2018 Journal of computational design and engineering Vol.5 No.4
Eye tracking is a technology that has quickly become a commonplace tool for evaluating package and webpage design. In such design processes, static two-dimensional images are shown on a computer screen while a subject’s gaze where he or she looks is measured via an eye tracking device. The collected gaze fixation data are then visualized and analyzed via gaze plots and heat maps. Such evaluations using two-dimensional images are often too limited to analyze gaze on three-dimensional physical objects such as products because users look at them not from a single point of view but rather from various angles. Therefore in this study we propose methods for collecting gaze fixation data for a three-dimensional model of a given product and visualizing corresponding gaze plots and heat maps also in three dimen-sions. To achieve our goals, we used a wearable eye-tracking device, i.e., eye-tracking glasses. Further, we implemented a prototype system to demonstrate its advantages in comparison with two-dimensional gaze fixation methods.