• Proceedings of the Korea Multimedia Society Conference
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• 1998.04a
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• pp.385-388
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• 1998

The main interest of previous researches for shape from shading was only on Lambertian surface which consists of diffuse reflectance surface. In practice, natural objects have hybrid reflectance, which limits the recovery of shape from intensity distribution[1][2]. In this paper, we propose the method of determining shape using neural network and diffuse illumination. The segmented region of sphere surface is used for training set, which can be determined by shadow line and edge of surface. Diffuse illumination is used to avoid specular spike and highlight which usually cause many problems such as intensity disparities. Diffuse illumination method using flat paper allows us to reduce these phenomena with simple scheme. Neural network and Diffuse illumination method are useful for shape from shading, because it can be applied to objects of unknown reflectance properties, but it is applied only to Torrance-Sparrow style reflectance.

• Journal of Fashion Business
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• v.18 no.3
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• pp.134-147
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• 2014

The aim of this study is to create smart wear that brings out the perspective person's individuality and creativity wearing these garments through various interactions. It is intended to build a prototype for a "Shape-folding Dress", which is length-adjustable skirt that responses with the environment of the wearer. In this process, four basic physical properties can be identified with fabric samples selected which are relatively stiff, including fusible interlining, organdy, silk, and ramie. In addition, two types of folding pattern specimens, "Basic Pattern" and "Diamond Pattern", and heat-steam were used to make the specimens so that the correlation could be calculated by recovery rate among flexing, stiffness and tensile properties. As a result, compared to other fabrics, the silk showed low stress to repeat folding and unfolding process, and its recovery rate of elongation deformation was stable without being affected by the different folding types and twice repeated process. In this study, forming a circuit using an Arduino, illuminance sensor, motors, and pulley, the prototype was created with a silk fabric.

• Smart Structures and Systems
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• v.24 no.2
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• pp.157-171
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• 2019

This study investigated the effects of the geometric parameters of superelastic shape memory alloy (SE SMA) fibers on the pullout displacement recovering and self-healing capacity of reinforced cementitious composites. Three diameters of 0.5, 0.7 and 1.0 mm and two different crimped lengths of 5.0 and 10.0 mm were considered. To provide best anchoring action and high bond between fiber and cement mortar, the fibers were crimped at the end to create spear-head shape. The single fiber cement-based specimens were manufactured with the cement mortar of a compressive strength of 84 MPa with the square shape at the top and a dog-bone shape at the bottom. The embedded length of each fiber was 15 mm. The pullout test was performed with displacement control to obtain monotonic or hysteretic behaviors. The results showed that pullout displacements were recovered after fibers slipped and stuck in the specimen. The specimens with fiber of larger diameter showed better displacement recovering capacity. The flag-shaped behavior was observed for all specimens, and those with fiber of 1.0 mm diameter showed the clearest one. It was observed that the length of fiber anchorage did not have a significant effect on the displacement recovery, pullout resistance and self-healing capacity.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.4
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• pp.347-354
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• 2012

The recovery force and displacement occur due to the phase transformation from the martensite phase to the austenite phase induced by the mechanical loading or thermal loading. These recovery force and displacement depend on an initial geometrical configuration of SMAs and loading conditions. Although the SMAs generally generates large recovery forces, the sufficient recovery displacement cannot be expected without a proper design strategy. The functionality of SMAs is limited due to the unbalance between the large recovery force and the small recovery displacement. This study suggests the double coil SMA spring in order to amplifying the recovery displacement induced by the phase transformation. By predicting the recovery displacement of doble coil SMA springs and one coil SMA springs induced by thermal loading, we show that the double coil SMA spring not only mitigate the unbalance of performance but also have a large recovery displacement for its recovery force than one coil SMA spring.

• International Journal of Human Ecology
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• v.8 no.2
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• pp.99-106
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• 2007

In this study, the mechanical properties related to the fabric appearance of well being functional bamboo knitted fabric before and after loess dyeing were evaluated. The mechanical properties of fabrics were measured by KES-F system, that is, shape retention, draping, wrinkle recovery, compression property, and surface properties, and total hand value of three types of knitted fabric, 100% bamboo, 100% cotton, and bamboo / cotton blend (60 / 40) were evaluated before and after loess dyeing. As a result, it was found that appearance density, shape retention, and drape coefficient of cotton knitted fabric were greater than those of bamboo knitted fabric. After loess dyeing, shape retention and drape coefficient, wrinkle recovery of bamboo knitted fabric improved and WC/C and MMD/SMD decreased. According to THV, the hand of bamboo/cotton blend knit is the best among three samples by compensation the weak properties of the two fiber. Therefore, loess dyeing seemed to be a good method for improving shape retention and hand value of 100% bamboo and bamboo blended fabric.

• Journal of the Korean Society for Heat Treatment
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• v.9 no.3
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• pp.187-197
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• 1996

In this study, the properties of coil spring made by Cu-Zn-Al and B added shape memory alloys are investigated. The measurement of recovery displacement and energy with increasing weight, and thermocycling properties have been studied using displacement measuring device. Transformation temperature and phase change by thermocycling have been also investigated by DSC and X-ray diffractometer. Grain size of the alloy is refined from 1.2mm to $400{\mu}m$ by 0.06wt% of B addition. The maximum recovery energy of the coil spring for B added alloy is larger than that of no B added alloy, it is because of grain refinement. And shape memory ability of the coil spring by thermocycling decrease with increasing thermocycling after thermocycle under load. The degradation of shape memory properties of coil spring by thermocycling is improved by B addition.

• Current Optics and Photonics
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• v.4 no.5
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• pp.411-420
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• 2020

Non-contact three-dimensional (3D) measuring technology is used to identify defects in miniature products, such as optics, polymers, and semiconductors. Hence, this technology has garnered significant attention in computer vision research. In this paper, we focus on shape from focus (SFF), which is an optical passive method for 3D shape recovery. In existing SFF techniques using interpolation, all datasets of the focus volume are approximated using one model. However, these methods cannot demonstrate how a predefined model fits all image points of an object. Moreover, it is not reasonable to explain various shapes of datasets using one model. Furthermore, if noise is present in the dataset, an error will be generated. Therefore, we propose an algorithm based on polynomial regression analysis to address these disadvantages. Our experimental results indicate that the proposed method is more accurate than existing methods.

• Journal of the Semiconductor & Display Technology
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• v.11 no.3
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• pp.19-25
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• 2012

The accuracy of Shape From Focus (SFF) technique depends on the quality of the focus measurements which are computed through a focus measure operator. In this paper, we introduce a new approach to estimate 3D shape of an object based on Gaussian process regression. First, initial depth is estimated by applying a conventional focus measure on image sequence and maximizing it in the optical direction. In second step, input feature vectors consisting of eginvalues are computed from 3D neighborhood around the initial depth. Finally, by utilizing these features, a latent function is developed through Gaussian process regression to estimate accurate depth. The proposed approach takes advantages of the multivariate statistical features and covariance function. The proposed method is tested by using image sequences of various objects. Experimental results demonstrate the efficacy of the proposed scheme.

• Journal of the Korean Society for Heat Treatment
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• v.14 no.3
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• pp.160-166
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• 2001

The change of ribbon geometry, microstructure and shape recovery with Mn contents, wheel speed and various annealing temperature have been studied in Fe-X%Mn-5Cr-5Co-4Si (X%=15, 20, 24) shape memory alloy (SMA) ribbons rapidly solidfied by single roll chill-block melt-spinning process. The thickness and width of melt-spun ribbons are reduced, results in refining and uniformalizing grains with increasing wheel speed. In the ribbons melt-spun at a wheel speed of 15m/sec, both ${\varepsilon}$ and ${\alpha}^{\prime}$martensites are formed in ribbon 1 (15.5wt%Mn), while only ${\varepsilon}$ martensite is revealed in ribbon 2 (20.2wt%Mn) and ribbon 3 (23.5wt%Mn). The volume fraction of ${\varepsilon}$ martensite is decreased with increasing Mn contents, and those of ${\varepsilon}$ as well ${\alpha}^{\prime}$martensites are increased due to thermal stress relief and grain growth with increasing annealing temperature. Ms temperatures of the ribbons 1, 2 and 3 are fallen with increasing Mn contents. $M_s$ temperatures of the ribbons 1, 2 and 3 annealed at $300^{\circ}C$ for 3 min are risen abruptly, but are nearly constant even at higher annealing temperature, i.e., 400, 500 and $600^{\circ}C$ for 3 min. Shape recovery of the ribbons 1, 2 and 3 increased 30%, 52% and 69% with Mn contents, respectively. Shape recovery of ribbon 1 (15.5wt%Mn) formed ${\varepsilon}$ and ${\alpha}^{\prime}$martensites decreased because of the presence of ${\alpha}^{\prime}$martensite but those of ribbon 2 (20.2wt%Mn) and ribbon 3 (23.5wt%Mn) formed ${\varepsilon}$ martensite increased with increasing annealing temperature.

• Journal of Korea Multimedia Society
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• v.10 no.3
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• pp.303-315
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• 2007

This paper proposes a 3D structure recovery and registration method that uses four or more common points. For each frame of a given video, a partial structure is recovered using tracked points. The 3D coordinates, camera positions and camera directions are computed at once by our improved scaled orthographic factorization method. The partially recovered point sets are parts of a whole model. A registration of point sets makes the complete shape. The recovered subsets are integrated by transforming each coordinate system of the local point subset into a common basis coordinate system. The process of shape recovery and integration is performed uniformly and linearly without any nonlinear iterative process and without loss of accuracy. The execution time for the integration is significantly reduced relative to the conventional ICP method. Due to the fast recovery and registration framework, our shape recovery scheme is applicable to various interactive video applications. The processing time per frame is under 0.01 seconds in most cases and the integration error is under 0.1mm on average.