• 제어로봇시스템학회논문지
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• 제22권9호
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• pp.733-737
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• 2016

In this paper, we propose a mechanism that can compensate for gravity in a robot manipulator. Industry robots generate torque due to carrying heavy weight. For this reason, the robots need high specification motors, which increases the prices of the robots and their production costs. In order to resolve these problems, a mechanism for gravity compensation has been developed using a spring and wire system. But this system has problems related to wire stretching. A winding mechanism is therefore used to supplement this drawback of the wire. The robot used was developed by the 1-DOF system. Analysis was performed for the performance of the mechanism. Experiments were conducted to compare simulation results and experimental results.

• Steel and Composite Structures
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• 제27권5호
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• pp.599-611
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• 2018

In this article a four unknown quasi-3D shear deformation theory for the bending analysis of functionally graded (FG) plates is developed. The advantage of this theory is that, in addition to introducing the thickness stretching impact (${\varepsilon}_z{\neq}0$), the displacement field is modeled with only four variables, which is even less than the first order shear deformation theory (FSDT). The principle of virtual work is utilized to determine the governing equations. The obtained numerical results from the proposed theory are compared with the CPT, FSDT, and other quasi-3D HSDTs.

• 소성∙가공
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• 제18권8호
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• pp.596-600
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• 2009

Finite element simulation is an alternative method to practically find the forming limit diagram(FLD). In this paper, the novel fracture criterion is utilized to predict the FLD in conjunction with finite element analysis for sheet forming. The principal scheme of the fracture criterion in this paper is that growth of the micro voids leads up to fracture in the viewpoint of micro-mechanics. The numerical FLD is verified by results of the out-of plane stretching test using hemispherical punch. The verification is also conducted about two types of material. These results are in good accord with the experimental results. Especially, the proposed scheme is appropriate to predict FLDs for a restricted material with low ductility after the instability point or ultimate tensile strength.

• 전자공학회논문지
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• 제51권2호
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• pp.124-132
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• 2014

본 논문은 퍼지 C-평균 분류기와 적응적 블록 분할을 사용한 역광 영역 검출과 공간 적응적 대비 확장을 사용한 역광 영역 개선 방법을 제안한다. 제안된 방법은 퍼지 이론에 의해 계산된 최적의 임계값을 기반으로 적응적 가변블록 분할을 사용하여 역광 영상을 어두운 역광 영역과 밝은 배경 영역으로 구분한다. 가변블록에 의한 블록화 현상을 없애기 위해 유도 필터(guided filter)를 사용하여 역광 영역을 객체 영역에 적합하게 세분화한다. 마지막으로 검출된 역광 영역은 공간 적응적으로 대비가 확장되어 조도를 개선한다. 제안된 방법은 최적의 임계값을 사용하여 영상을 분할하기 때문에 입력 영상에 따라 적응적으로 영역을 분할하고 저조도 영역을 개선하며, 사용자의 별도의 설정이 없이 입력 영상에 따라 자동적 역광 영상 개선이 가능하다. 실험 결과를 통해 제안된 방법이 기존 방법보다 역광 영역에 존재하는 피사체의 정보를 효과적으로 개선할 수 있으며, 복잡한 분할 방법을 사용하지 않고 빠르게 역광 영역을 검출할 수 있음을 보인다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권4호
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• pp.1904-1926
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• 2016

Iris recognition for biometric personnel identification has gained much interest owing to the increasing concern with security today. The image quality plays a major role in the performance of iris recognition systems. When capturing an iris image under uncontrolled conditions and dealing with non-cooperative people, the chance of getting non-ideal images is very high owing to poor focus, off-angle, noise, motion blur, occlusion of eyelashes and eyelids, and wearing glasses. In order to improve the accuracy of iris recognition while dealing with non-ideal iris images, we propose a novel algorithm that improves the quality of degraded iris images. First, the iris image is localized properly to obtain accurate iris boundary detection, and then the iris image is normalized to obtain a fixed size. Second, the valid region (iris region) is extracted from the segmented iris image to obtain only the iris region. Third, to get a well-distributed texture image, bilinear interpolation is used on the segmented valid iris gray image. Using contrast-limited adaptive histogram equalization (CLAHE) enhances the low contrast of the resulting interpolated image. The results of CLAHE are further improved by stretching the maximum and minimum values to 0-255 by using histogram-stretching technique. The gray texture information is extracted by 1D Gabor filters while the Hamming distance technique is chosen as a metric for recognition. The NICE-II training dataset taken from UBRIS.v2 was used for the experiment. Results of the proposed method outperformed other methods in terms of equal error rate (EER).

• Computers and Concrete
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• 제32권1호
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• pp.61-74
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• 2023

This article investigates the wave propagation analysis of the imperfect functionally graded (FG) sandwich plates based on a novel simple four-variable integral quasi-3D higher-order shear deformation theory (HSDT). The thickness stretching effect is considered in the transverse displacement component. The presented formulation ensures a parabolic variation of the transverse shear stresses with zero-stresses at the top and the bottom surfaces without requiring any shear correction factors. The studied sandwich plates can be used in several sectors as areas of aircraft, construction, naval/marine, aerospace and wind energy systems, the sandwich structure is composed from three layers (two FG face sheets and isotropic core). The material properties in the FG faces sheet are computed according to a modified power law function with considering the porosity which may appear during the manufacturing process in the form of micro-voids in the layer body. The Hamilton principle is utilized to determine the four governing differential equations for wave propagation in FG plates which is reduced in terms of computation time and cost compared to the other conventional quasi-3D models. An eigenvalue equation is formulated for the analytical solution using a generalized displacements' solution form for wave propagation. The effects of porosity, temperature, moisture concentration, core thickness, and the material exponent on the plates' dispersion relations are examined by considering the thickness stretching influence.

• 한국초등과학교육학회지:초등과학교육
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• 제42권1호
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• pp.149-160
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• 2023

한국어판 SCILE(30)설문지를 요인분석방법을 사용하여 과학호기심 설문지인 한국어판 SCILE(15)설문지를 개발하였다. 먼저 한국어판 SCILE(30)설문지를 사용하여 초등예비교사들을 대상으로 설문 조사를 시행한 후에 요인분석을 수행하였다. 요인분석결과, '과학실천형' 호기심, '확장형' 호기심, '포용형' 호기심 요인의 3가지 요인으로 구성된 15문항의 한국어판 SCILE(15)설문지가 얻어졌다. 한국어판 SCILE(15)설문지에 대한 확인적 요인분석에 의한 요인구조를 분석한 결과, 각 요인 간에 상관관계를 보여 과학호기심요인으로서의 공통성이 확인되었다. 한국어판 SCILE(15)설문지의 전체문항에 대한 신뢰도와 각 요인별 문항들에 대한 신뢰도는 크론바흐 알파 0.700 이상으로 평가되어 과학호기심 설문지인 한국어판 SCILE(15)설문지는 신뢰성이 있는 것으로 평가되었다. 설문지개발을 위한 설문 조사에 참석한 초등예비교사들은 과학호기심에 대하여 '과학실천형' 호기심, '확장형' 호기심, '포용형' 호기심 요인을 인식하고 있었다. 세 종류의 과학호기심 요인들에 대하여 일반선형모형으로 분석한 결과 호기심요인들은 서로 유의미한 차이를 보였다. 이러한 결과는 초등예비 교사들은 '과학실천형' 호기심요인, '확장형' 호기심요인, '포용형' 호기심요인을 인식하는 정도가 다르다는 것을 나타낸다. 초등예비교사는 과학호기심의 세 가지 요인 중에서 '확장형' 호기심요인의 인식정도가 가장 높았고, '포용형' 호기심요인의 인식정도는 가장 낮은 특성을 보였다.

• Bulletin of the Korean Chemical Society
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• 제30권10호
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• pp.2227-2232
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• 2009

Novel polythiol materials of urethane lens series for plastic optical lens were synthesized from polyol materials via thioisouronium of thiourea with c-HCl in refluxing aqueous solution, in which polythiol material was carried out from hydrolysis of thioisouronium by ammonia water. Their structure properties were identified by EA, EI-MS, FT-IR, $^1H\;and\;^{13}C$ NMR spectroscopies and TGA. Their ophthalmic lenses as polythiourethane material were prepared by thermal curing to an injected glass mold using the evenly solutions of diisocyanates series (TDI, XDI, HDI or IPDI) with polythiols. Polythiourethane shows that the strong stretching mode for SH group of polythiol disappeared in FT-IR spectra after thermosetting polymerization. Thermal deformation starting temperature of ophthalmic lenses was determined by TMA. Ophthalmic lenses made from characteristic polythiol and diisocyanate series have transparency, colorless and good impact strength, in which thermal resistance and impact strength of ophthalmic lenses were influenced by diisocyanate series. Physical properties of ophthalmic lens have contrast thermal resistance with impact strength. The property of thermal resistance and impact strength for respective ophthalmic lenses was examined by TMA and drop ball test.

• Geomechanics and Engineering
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• 제34권3호
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• pp.233-250
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• 2023

This paper investigates the flexural analysis of isotropic, transversely isotropic, and laminated composite plates using a new higher-order normal and shear deformation theory. In the present theory, only five unknown functions are involved compared to six or more unknowns used in the other similar theories. The developed theory does not need a shear correction factor. It can satisfy the zero traction boundary conditions on the top and the bottom surfaces of the plate as well as account for sufficient distribution of the transverse shear strains. The thickness stretching effect is considered in the computation. A simply supported was considered on all edges of the plate. The plate is subjected to uniform and sinusoidal distributed load in the static analysis. Laminated composite, isotropic, and transversely isotropic plates are considered. The governing equations are obtained utilizing the virtual work principle. The differential equations are solved via Navier's procedure. The results obtained from the developed theory are compared with other higher-order theories considered in the previous studies and 3D elasticity solutions. The results showed that the proposed theory accurately and effectively predicts the bidirectional bending responses of laminated composite plates. Several parametric studies are presented to illustrate the various parameters influencing the static response of the laminated composite plates.

• Asian Pacific Journal of Cancer Prevention
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• 제13권8호
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• pp.3705-3708
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• 2012

Effects of Cantharidinate on apoptosis of human colorectal cancer UTC-116 cells were investigated by means of 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, H and E staining, flow cytometry, and Raman Spectra analysis. The results showed Cantharidinate to exert inhibitory action on proliferation of human colorectal cancer UTC-116 cells, inducing apoptosis, arresting cells in G1 phase, with decline of S and G2 phases. In addition, the results of Raman spectrum showed significant changes in the UTC-116 cells chemical structure with stretching after the application of Cantharidinate. Taken together, these results suggest that the treatment of human colorectal cancer with Cantharidinate may be associated with multiple molecular mechanisms for apoptosis. Furthermore, similar to fluorouracil, Cantharidinate should be considered as novel assistant drug for controlling the growth of human colorectal cancer UTC-116 cells.