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Evaluation of Surface Crack and Blind Crack by Induced Current Focusing Potential Drop(ICFPD) Technique (집중유도형 교류전위차법에 의한 표면결함 및 이면결함의 평가에 관한 연구)

  • Kim, Hoon
    • Journal of the Korean Society for Nondestructive Testing
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    • v.16 no.2
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    • pp.86-94
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    • 1996
  • In the life management safety evaluation of constructs base on a fracture mechanics, the size of defect is the very important parameter. ICFPD (Induced Current Focusing Potential Drop)technique has been developed for detecting and sizing of defects that exist not only on surface but also inside and interior of structural components. The principle of this technique is to induce a focusing current at an exploration region by a straight induction wire through which an alternating current (AC)flows that has constant amplitude and frequency. The potential distributed on the surface of metallic material is measured by potential pick-up pins that are settled on the probe. In this paper, this NDI technique was applied to the evaluation of surface cracks and blind cracks in plate specimens. The results of this study show that in the case of surface crack, the distribution of potential drop is varied with the inched angle of surface crack, and the potential drops in the crack region and the crack edge region are varied with the inclined angle and depth of crack. The distribution of potential drop for the blind crack is distingulished from that for the surface crack, and the potential drop in the crack region is varied with the depth of crack.

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Adaptive prototype generating technique for improving performance of a p-Snake (p-Snake의 성능 향상을 위한 적응 원형 생성 기법)

  • Oh, Seung-Taek;Jun, Byung-Hwan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.4
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    • pp.2757-2763
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    • 2015
  • p-Snake is an energy minimizing algorithm that applies an additional prototype energy to the existing Active Contour Model and is used to extract the contour line in the area where the edge information is unclear. In this paper suggested the creation of a prototype energy field that applies a variable prototype expressed as a combination of circle and straight line primitives, and a fudge function, to improve p-Snake's contour extraction performance. The prototype was defined based on the parts codes entered and the appropriate initial contour was extracted in each primitive zones acquired from the pre-processing process. Then, the primitives variably adjusted to create the prototype and the contour probability based on the distance to the prototype was calculated through the fuzzy function to create the prototype energy field. This was applied to p-Snake to extract the contour from 100 images acquired from various small parts and compared its similarity with the prototype to find that p-Snake made with the adaptive prototype was about 4.6% more precise than the existing Snake method.

Long-Range Surface-Plasmons Excited on Double-Layered Metal Waveguides (이중-금속 장거리 표면-플라즈몬 도파로)

  • Joo, Yang-Hyun;Jung, Myong-Jin;Song, Seok-Ho
    • Korean Journal of Optics and Photonics
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    • v.19 no.1
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    • pp.73-79
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    • 2008
  • We propose a novel metal-waveguide structure for sustaining long-range surface-plasmon-polaritons (LRSPP). The LRSPP waveguides are composed basically of two asymmetric metal layers: a very thin, finite-width metal strip on top of a metal slab with a dielectric gap in between them. Mode cut-off of LRSPPs excited on the double-metal waveguides is characterized by consistently investigating their dispersion relations and mode profiles. We also confirm experimentally the existence of low-loss, well-confined LRSPP modes by measuring far-field outputs emerging from an edge of the asymmetric double-metal waveguides. In the experiment, we have fabricated several types of SPP waveguide devices including straight lines, S-bend, and Y-branch consisting of gold strips (20 nm-thick, $5{\mu}m$-wide). Overall propagation loss of the proposed double-metal waveguides is quite comparable to that of single metal-strip waveguides, in addition the mode sizes can be tuned by increasing the core-insulator gap between the metal layers to get a higher coupling efficiency with a single-mode fiber in telecom wavelength. The proposed LRSPP waveguides may open up realization of SPP-waveguide sensors or nonlinear SPP-devices by replacing the core-insulator with a bio-fluid or a nonlinear medium.

A Mechanical Model of Excimer Laser Surgery (엑시머 레이저 수술의 역학적 모델)

  • Shin, Jung-Woog;Kim, Jong-Hyun
    • Proceedings of the KOSOMBE Conference
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    • v.1993 no.05
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    • pp.57-60
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    • 1993
  • A finite element-based computer simulation of excimer laser susery was conducted to study some factors on the surgery. In particular, the radius of curvature at the apex of the cornea was examined under various surgical conditions. Corneal tissue was assumed to be a nearly incompressible, linear elastic, homogeneous, isotropic material under very small deformation. The geometry of the human cornea was taken from the experimental data[1]. The simulation utilized ANSYS(Swanson Analysis System Inc.Rev.4.4A). In this study, the major factors which affect the outcomes of the excimer laser surgery were investigated. First, two patterns of surgery with various surgery thickness(40-70micrometers) were examind. The pattern#1 describes the meridian from the apex to the edge of the surgery area to be straight. And the corresponding meridian of the pattern 2 can be expressed as a quardratic function. The results show that the pattern #2 is more realistic and effective. Then, the effects of other factors were investigated based on the pattern #2. Other factors are:various diameters of the surgical area (3-8 milimeters), Young's modules(3.5-4.5MPa), and depth of surgery at the apex(40-70micrometers). Compared with the computer simulation of the radial keratotomy surgery[2], the excimer laser surgery was proven to be more effective in treating myopia patients. In conculusion, the results of the simulation are qualitative agreement with clinical experience[3] indicating the potential of the finite element model of the surgery as a guideline to the surgeon before actual surgery.

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Magnetic Domain Walls at the Edges of Patterned NiO/NiFe Bilayers (패턴된 이중박막의 자구벽 특성조사)

  • Hwang, D.G.;Lee, S.S.
    • Journal of the Korean Magnetics Society
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    • v.13 no.4
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    • pp.176-181
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    • 2003
  • The magnetic domain walls at the edges of a large patterned and exchanged-biased NiO(10-60 nm)/NiFe(10 nm) bilayers and their motions with applied field were investigated by magnetic force microscopy. Three kinds of domain walls, namely, head-to-head zig-zag and tail-to-tail zig-zag Bloch walls and straight Neel walls were found at specific edges of the unidirectional biased NiO(30 nm)/NiFe(10 nm) bilayer having the exchange biasing field (H$\sub$ex/) of 21 Oe. No walls were observed for the strong exchange-biased bilayer (60 nm NiO, H$\sub$ex/ = 75 Oe), while the amplitude of the zig-zag domain increased with decreasing exchange biasing. This may be explained by mutual restraint between H$\sub$ex/ and the demagnetization field of edge. We similarly investigated the magnetization reversal process, the subsequent motion of the walls and identified the pinning and nucleation sites during reversal.

A study on Simple and Complex Algorithm of Self Controlled Mobile Robot for the Obstacle Avoidance and Path Plan (자율 이동로봇의 장애물 회피 및 경로계획에 대한 간략화 알고리즘과 복합 알고리즘에 관한 연구)

  • 류한성;최중경;구본민;박무열;권정혁
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.6 no.1
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    • pp.115-123
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    • 2002
  • In this paper, we present two types of vision algorithm that mobile robot has CCD camera. for obstacle avoidance and path plan. One is simple algorithm that compare with grey level from input images. Also, The mobile robot depend on image processing and move command from PC host. we has been studied self controlled mobile robot system with CCD camera. This system consists of TMS320F240 digital signal processor, step motor, RF module and CCD camera. we used wireless RF module for movable command transmitting between robot and host PC. This robot go straight until 95 percent filled screen from input image. And the robot recognizes obstacle about 95 percent filled something, so it could avoid the obstacle and conclude new path plan. Another is complex algorithm that image preprocessing by edge detection, converting, thresholding and image processing by labeling, segmentation, pixel density calculation.

The Distribution Condition and Clothing Construction Factors of the Working Clothes - Reference to the Changwon National Industrial Complex -

  • Park, Gin-Ah;Park, Hye-Won
    • Journal of Fashion Business
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    • v.12 no.3
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    • pp.116-135
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    • 2008
  • To investigate the actual distribution condition and clothing construction factors of the working clothes supplied to the Changwon national industrial complex, 5 major companies in machinery, automotive, industrial engineering, shipbuilding and rolling stock in the industrial complex located in Gyeongsangnam-Do were selected. The questionnaire designed for the research consisted of working clothes distribution policies in manufacturing industry and the actual conditions of the design facts, repair and maintenance of the working clothes, etc. The analysis of the clothing construction factors of the working clothes provided by 5 respondent companies were conducted in parallel. The results derived from the study were as follows: The basic types of working clothes were the blouson jacket and straight pants; safety equipments for manufacture were safety helmets, gloves, snickers, goggles, masks, ear caps, wristlets, leggings, apron, etc. The size-charts adopted by the participant companies were the small-medium-large and cm/inch measurement size systems. To solve wearer's dissatisfaction with the garment fit, certain clothing construction factors were used, e.g. strap bands and the elastic band on a waist band. The types of fabrics used for the working clothes were mainly polyester/cotton and polyester/rayon blended ones. Moreover, to provide with more air permeability to wearers, the warp knit material was used to construct the lining and the armpit or back bodice slits. Lock, two-thread chain, safety, overedge stitches were applied with flat, lap felled, French, superimposed, lapped, bound and edge finishing seams to construct the working clothes selected.

The Effects of Muscle Energy Technique on the Shoulder Complex Range of Motion and Posture Alignment of Female College Students in their Twenties with a Round Shoulder (근에너지기법이 둥근어깨를 가진 20대 여대생의 어깨복합체 가동성과 자세정렬에 미치는 영향)

  • Im, Gyeong-eun;Jeong, Yeon-woo;Seo, Tae-hwa
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.27 no.2
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    • pp.17-25
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    • 2021
  • Background: The purpose of this study is to investigate basic data about the effects of muscle energy technique on the shoulder complex range of motion and posture alignment in the round shoulder posture. Methods: The subjects included 15 women that gave consent to participate in the study voluntarily. They performed the muscle energy technique for 30 minutes twice. The round shoulder posture was measured with a straight edge ruler. The shoulder complex range of motion was measured with the apley scratch test. The forward head posture was measured with ImageJ. The pectoralis minor muscle length was measured with a tape measure. Results: There were statistically significant differences in the round shoulder posture both right and left (p<.05). The experiment group showed statistically significant differences in the pectoralis minor muscle length (p<.05). There were significant differences in the shoulder complex range of motion including flexion, left lateral flexion, right lateral flexion, left side bending, and right side bending (p<.05), but no significant differences were found in extension (p>.05). The forward head posture showed significant differences in CVA changes (p<.05) and no significant differences in CRA changes (p>.05). Conclusion: These findings demonstrate that the muscle energy technique relaxed muscles around the shoulders and increased the shoulder complex range of motion. The technique is also expected to prevent pain in the neck and shoulders and lower injury risk. In conclusion, the muscle energy technique can be applied as an effective intervention for round shoulder posture.

Algorithm for Cross-avoidance Bypass Routing in Numberlink Puzzle (숫자 연결 퍼즐에 관한 교차 회피 우회 경로 알고리즘)

  • Sang-Un Lee
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.24 no.3
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    • pp.95-101
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    • 2024
  • The numberlink puzzle(NLP), which non-crossings with other numbers of connection in connecting lines through empty cells between a given pair of numbers, is an NP-complete problem with no known way to solve the puzzle in polynomial time. Until now, arbitrary numbers have been selected and puzzles have been solved using trial-and-error methods. This paper converts empty cells into vertices in lattice graphs connected by edge between adjacent cells for a given problem. Next, a straight line was drawn between the pairs of numbers and divided into groups of numbers where crossing occurred. A bypass route was established to avoid intersection in the cross-number group. Applying the proposed algorithm to 18 benchmarking data showed that the puzzle could be solved with a linear time complexity of O(n) for all data.

Path Matching Algorithm for Bridges Puzzle (가교 퍼즐에 관한 경로 매칭 알고리즘)

  • Sang-Un Lee
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.24 no.4
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    • pp.99-106
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    • 2024
  • The problem of the bridges(Hasjiwokakero, Hasi) puzzle, which connects the bridge(edge) required by the island(vertex) without crossing the horizontal and vertical straight bridges except for the diagonal to form a connected network, is a barren ground for research without any related research. For this problem, there is no algorithm that presents a generalized exponential time brute-force or branch-and-bound method. This paper obtained the initial solution of the lattice graph by drawing a grid without diagonal lines for a given BP, removing unnecessary edges, and supplementing essential bridges. Next, through insufficient island pair path matching, the method of adding insufficient edges to the route and deleting the crossed surplus edges(bridges) was adopted. Applying the proposed algorithm to 24 benchmarking experimental data showed that accurate solutions can be obtained for all problems.