• Journal of the Korean Society of Visualization
• /
• v.19 no.3
• /
• pp.54-62
• /
• 2021

This study has investigated the 3-D deflection characteristics of a flexible plate levitated by non-contact grippers using SPIV method. The measuring instrument consisted of a flexible plate located under four non-contact grippers and two cameras at the bottom of a transparent acrylic plate. Measurements were made on two materials (PVC and PC) for the plate with 50×50 cm2 area and 1 mm thickness. The deflection characteristics and flatness vary depending on the plate material, the gripper position and the air flow supplied to the gripper. For the material of PVC, the overall defection is convex. As the gripper position goes outward from the plate center, the upmost bending point also moves to the outside of the plate with the flatness increasing. However, the air flow rate does not affect the deflection pattern except for the small increase of flatness. For the material of PC, the shape of deflection changes from convex to concave as the gripper position goes out. The flatness is the highest at the point of transition from convex to concave, but the air flowrate has little effect on the flatness.

• Steel and Composite Structures
• /
• v.46 no.3
• /
• pp.353-366
• /
• 2023

This paper presents a finite-element analysis (FEA) of aluminum alloy rectangular hollow sections (RHSs) and square hollow sections (SHSs) with circular through-openings under three-point and four-point bending. First, a finite-element model (FEM) was developed and validated against the corresponding test results available in the literature. Next, using the validated FE models, a parametric study comprising 180 FE models was conducted. The cross-section width-to-thickness ratio (b/t) ranged from 2 to 5, the hole size ratio (d/h) ranged from 0.2 to 0.8 and the quantity of holes (n) ranged from 2 to 6, respectively. Third, results obtained from laboratory test and FEA were compared with current design strengths calculated in accordance with the North American Specifications (NAS), the modified direct strength method (DSM) and the modified Continuous strength method (CSM). The comparison shows that the modified CSM are conservative by 15% on average for aluminum alloy RHSs and SHSs with circular through-openings subject to bending. Finally, a new design equation is proposed based on the modified CSM after being validated with results obtained from laboratory test and FEA. The proposed design equation can provide accurate predictions of flexural capacities for aluminum alloy RHSs and SHSs with circular through-openings.

• Journal of Sasang Constitution and Immune Medicine
• /
• v.14 no.1
• /
• pp.51-66
• /
• 2002

The main purpose of this study is to differentiate Sasang Constitutions of men and women by measuring 5 parts of the body. By the definitions about Four Chos(四焦) in ${\ulcorner}$The Discourse on Viscera and Bowels(臟腑論)${\lrcorner}$, the body is divided into four parts and sets up the five borderlines. They are Top-line, Bosom-line, Stomach-line, Navel-line and Bottom-line. Top-line(第一線) is the horizontal distance between Rt. & Lt. Coracoid processes passing through the acupuncture point CV-22(天突穴) or the horizontal distance between Rt. & Lt. beginning points of Axillary lines. Bosom-line(第二線) is the horizontal distance passing through Rt.& Lt. Nipples. Stomach-line(第三線) is the horizontal distance passing through Rt.& Lt. acupuncture point ST-19(不容穴). Navel-line(第四線) is the horizontal distance passing through the navel(CV-8; 神闕穴) and the acupuncture point ST-25(天樞穴). Bottom-line(第五線) is the horizontal distance between Rt. & Lt. Anterior Superior Iliac Spine(ASIS). The measured numerical values of Five Lines are the most important factors to classify the Four Constitutions(Taeyangin, Taeumin, Soyangin, Soeumin). Among the five lines, Stomach-line(Middle-line) is the base line to decide Yin and Yang. As a result, I could differentiate the four Constitutions as follows. 1. Taeyangin's Top-line is more than 36cm long. Top-line is the longest. Bottom-line is the shortest. The length-difference between Top-line and Bottom-line is more or less 10cm long. 2. In case of Taeumin, Navel-line is the longest. The numerical values of Middle and Bottom lines are almost the same or Bottom-line is shorter than Middle-line by 1 or 2 cm long. In some special case, the five lines are all the same and the body just looks like a log. 3. In case of Soyangin, just like Taeyangin, Top-line is the longest. Bottom-line is the shortest. The length of Top-line is ranged between 30cm to 35cm long. From Top-line to Bottom-line, the length gradually diminishes each by 2cm: for example, 34-32-30-28-26. 4. In case of Soeumin, the longest one is Bottom-line. Specially, Navel-line is shorter than Middle-line. Bottom-line is longer than the Middle.

• Journal of Korean Society of Water and Wastewater
• /
• v.12 no.3
• /
• pp.99-106
• /
• 1998

This paper presents a procedure for determining the design rainfall depth and the design rainfall intensity at Incheon city area in Korea. In this study the eight probability distributions are considered to estimate the probable rainfall depths for 11 different durations. The Kolmogorov - Smirnov test and the Chi-square test are adopted to test each distribution. The probable rainfall intensity formulas are then determined by i) the least squares (LS) method, ii) the least median squares (LMS) method, iii) the reweighted least squares method based on the LMS (RLS), and iv) the constrained regression (CR) model. The Talbot, the Sherman, the Japanese, and the Unified type are considered to determine the best type for the Incheon station. The root mean squared (RMS) errors are computed to test the formulas derived by four methods. It is found that the Unified type is the most reliable and that all methods presented herein are acceptable for determining the coefficients of rainfall intensity formulas from an engineering point of view.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.5 no.1
• /
• pp.59-65
• /
• 1987

This paper presented the procedures for detecting gross errors, and described the influence of the number and distribution of points on the internal reliability in photogrammetric adjustment, such as relative orientation and independent model method. The use of the standard six points for relative orientation and the regular four points for independent model method result in low internal reliability. With such a distribution, gross erors in measured points might not be detected But using cluster of double or triple points instead of individual point, internal reliability improves remarkably.

• Proceedings of the Korean Information Science Society Conference
• /
• 2010.06a
• /
• pp.246-247
• /
• 2010

This paper proposes a fast motion estimation algorithm based on motion speed and multiple initial center points. The proposed method predicts initial search points by means of the spatio-temporal neighboring motion vectors. A dynamic search pattern based on motion speed and the predicted initial center points is proposed to quickly obtain the motion vector. Due to the usage of the spatio-temporal information and the dynamic search pattern, the proposed method greatly accelerates the search speed while maintaining a good predicted image quality. Experimental results show that the proposed method has a good predicted image quality in terms of PSNR with less search time as compared to the Full Search, New Three-Step Search, and Four-Step Search.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.11 no.5
• /
• pp.373-378
• /
• 2001

The optimization method based on an enhanced genetic algorithms is for multimodal function optimization in this paper. This method is consisted of two main steps. The first step is a global search step using the genetic algorithm(GA) and function assurance criterion(FAC). The belonging of an population to initial solution group is decided according to the FAC. The second step is to decide the similarity between individuals, and to research the optimum solutions by single point method in reconstructive search space. Four numerical examples are also presented in this papers to comparing with conventional methods.

• Proceedings of the KSME Conference
• /
• 2001.11a
• /
• pp.129-136
• /
• 2001

The remaining life estimation for the aged components in power plants as well as chemical plants are very important beacuse mechanical properties of the components are degraded with time of service exposure in high temperature. Since it is difficult to take specimens from the operating components to evaluate mechanical properties of components, nondestructive techniques are needed to estimate the degradation. In this study, test materials with 4 different degradation levels were prepared by isothermal aging heat treatment at $630^{\circ}C$. And the DC potential drop method and destructive methods such as tensile, $K_{IC}$ and hardness tests were used in order to evaluate the degradation of 1Cr-1Mo-0.25V steels. The objective of this study is to investigate the possibility of the application of DCPD method to estimate the material degradation, and to analyse the relationship between the electrical resistivity and the degree of material degradation.

• Journal of Institute of Control, Robotics and Systems
• /
• v.8 no.6
• /
• pp.439-444
• /
• 2002

In this paper, a new model reduction method is proposed to obtain a reduced order model in the frequency domain. The method is developed based on the second-order plus dead time modeling technique. The initial value of the reduced model parameters can be obtained using this method coinciding four point(0, -$\pi$/2, -$\pi$, -3$\pi$/2) on the Nyquist curve. The optimal parameters of the reduced model is obtained through calculation procedure with three steps. It is shown that Nyquist curves and unit step responses of the reduced models of numerical examples closely agree with those of original models.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.929-930
• /
• 2007

박막재료 및 반도체의 면저항 측정에는 주로 Four Point Probe(FPP) 원리를 이용한 측정기를 사용하고 있다. FPP에 의한 측정방식은 single 및 dual configuration method가 있으며, dual configuration은 single configuration에 비해 probe spacing 변화나 시료의 가장자리 효과 등에서 측정편차가 적은 장점이 있어서 dual configuration 기술을 사용하는 추세이다. 개발된 휴대용 면저항 측정기는 dual configuration원리를 적용하여 제작되었으며, 박막재료의 면저항을 누구나 쉽고 정확하게 측정할 수 있도록 설계되었다. 또한 시료의 크기가 핀 간격에 비해 5배 이상 크면 보정계수를 거의 무시할 수 있는 장점이 있어 작은 시료라도 정확한 면저항을 측정할 수 있다. 이측정기의 측정 불확도는 지시값의 1 % 이하이고, 측정범위는 (2$\sim$2000)$\Omega/sq$이다.