• Title/Summary/Keyword: Light propagation

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Penetration depth and Wave Propagation in Random Media (무질서한 매질에서 침투깊이와 파동 전파)

  • Kim, Ki-Jun;Sung, Ki-Chun
    • Journal of the Korean Applied Science and Technology
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    • v.23 no.1
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    • pp.70-76
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    • 2006
  • The influence of fluorophor, scatterer, absorber in turbid materials by light scattering were interpreted for the scattered fluorescence intensity and wavelength, it is studied the molecular property by laser induced fluorescence spectroscopy. It can be found that the effects of optical property are penentrated in scattering media by the optical $parameters({\mu}s$, ${\mu}a$, ${\mu}t$, ${\gamma}$, ${\rho})$. The value of scattering coefficient ${\mu}s$ is large appeared by means of the increasing particles of scattering, it can be found that the slope appears exponentially as a function of distance from laser source to detector. It may also utilize in designing the best model for oil chemistry, laser medicine and application of medical engineering.

Asymbiotic seed germination and in vitro propagation condition in Calanthe discolor Lindl.

  • Kwon, Huyk Joon;Shin, So Lim;Bae, Kee Hwa;Kim, Soo-Young
    • Journal of Species Research
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    • v.6 no.1
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    • pp.68-75
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    • 2017
  • We investigated the effects of sodium hypochlorite (NaOCl) and culture medium on embryo swelling and germination of Calanthe discolor Lindl., and established a method for determining the swelling and protocorm formation of C. discolor seeds via in vitro examination of immature seeds. Treatment of immature seeds with NaOCl greatly enhanced the extent of embryo swelling and protocorm formation of immature zygote embryos compared to seeds without NaOCl treatment. The effects of the culture media were also evaluated with regard to embryo swelling and protocorm formation of in vitro cultured seeds with and without NaOCl treatment. Additionally, the effects of white fluorescent light and red and blue LEDs lights on seedling growth in in vitro culture were examined. The most suitable condition for seedling growth after 12 weeks of culture was the red LEDs light with POM medium. These results show effective asymbiotic germination and growth of C. discolor.

Neural Network Based Camera Calibration and 2-D Range Finding (신경회로망을 이용한 카메라 교정과 2차원 거리 측정에 관한 연구)

  • 정우태;고국원;조형석
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1994.10a
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    • pp.510-514
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    • 1994
  • This paper deals with an application of neural network to camera calibration with wide angle lens and 2-D range finding. Wide angle lens has an advantage of having wide view angles for mobile environment recognition ans robot eye in hand system. But, it has severe radial distortion. Multilayer neural network is used for the calibration of the camera considering lens distortion, and is trained it by error back-propagation method. MLP can map between camera image plane and plane the made by structured light. In experiments, Calibration of camers was executed with calibration chart which was printed by using laser printer with 300 d.p.i. resolution. High distortion lens, COSMICAR 4.2mm, was used to see whether the neural network could effectively calibrate camera distortion. 2-D range of several objects well be measured with laser range finding system composed of camera, frame grabber and laser structured light. The performance of 3-D range finding system was evaluated through experiments and analysis of the results.

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A Study on the Wild Rhododendron Micranthum for Landscape Use (꼬리진달래의 造景樹木化를 위한 基礎硏究(III) -繁殖 實驗을 中心으로-)

  • Lee, Byoung-Ryong;Lee, Ki-Eui;Yoo, Keun-Chang
    • Journal of the Korean Institute of Landscape Architecture
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    • v.18 no.3 s.39
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    • pp.137-141
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    • 1990
  • This study was carried out to investigate the propagation methods of the Rhododendron micranthum as a landscape plant The results obtained are as follows : 1. The optimum temperature for seed germination was $20^{\circ}C$, and the seed germination needs light. 2. GA and thiourea did not affect the seed germination under light, but GA gad substitutive effect. 3. 87% and over of germination rates were obtained in room temperature and $5^{\circ}C$ dry storages. 4. The rooting rate was high on sandy loam, vermiculite, and vermiculite 50%+sand 50%, at softwood and hardwood cutting(hardwood ; 45~48%, softwood ; 45~48%). 5. The significant effects on rooting were found with the treatment of NAA 500~2000ppm.

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A Dynamic Accuracy Estimation for GPU-based Monte Carlo Simulation in Tissue Optics

  • Cai, Fuhong;Lu, Wen
    • Current Optics and Photonics
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    • v.1 no.5
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    • pp.551-555
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    • 2017
  • Tissue optics is a well-established and extensively studied area. In the last decades, Monte Carlo simulation (MCS) has been one of the standard tools for simulation of light propagation in turbid media. The utilization of parallel processing exhibits dramatic increase in the speed of MCS's of photon migration. Some calculations based on MCS can be completed within a few seconds. Since the MCS's have the potential to become a real time calculation method, a dynamic accuracy estimation, which is also known as history by history statistical estimators, is required in the simulation code to automatically terminate the MCS as the results' accuracy achieves a high enough level. In this work, spatial and time-domain GPU-based MCS, adopting the dynamic accuracy estimation, are performed to calculate the light dose/reflectance in homogeneous and heterogeneous tissue media. This dynamic accuracy estimation can effectively derive the statistical error of optical dose/reflectance during the parallel Monte Carlo process.

A Study on the Biotelemetry using Infra-red Light (적외선을 이용한 생체신호의 원격측정에 관한 연구)

  • Huh, Soo-Jin
    • Journal of Biomedical Engineering Research
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    • v.14 no.2
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    • pp.169-175
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    • 1993
  • Recently, interest in infra-red(IR) telemetry has increased because of the entirely different propagation and reflection properties of IR light as compared to radiowaves. IR hardly penetrates most materials and is reflected from obstacles. An biotelemetry system using these characteristics of indirect transmitted IR lights was developed, in which 3 ECG's are multiplexed and modulated in PDM/PIM pulse sequence. This proto-type system enables us to realize the non-restraint measurement of biological signals. Compared with conventional radio telemetry, this technique has some merits such as no electromagnetic interference, no frequency allocation problem, no government control over transmission power.

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Optical-Loss Measurement of a Silicon-Slab Waveguide

  • Tresna, Wildan Panji;Putra, Alexander William Setiawan;Maruyama, Takeo
    • Current Optics and Photonics
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    • v.4 no.6
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    • pp.551-557
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    • 2020
  • A mirror-in-slab waveguide is fabricated on a slab waveguide by using the refractive-index contrast between two materials, with the reflection performance depending on the slab waveguide's design. In this research, a slab waveguide design consisting of silicon (Si) as the core and SiO2 as the substrate was designed and developed to determine the coupling, waveguide, and mirror losses. Based on experimental results, coupling loss is dominant and is affected by the design of the slab waveguide. Furthermore, the mirror loss is affected by the design of the mirror, such as the curvature radius and the size of the mirror. TE and TM polarizations of light are used in the measurements. The experimental results show that mirror losses due to reflection by mirrors are 0.011 dB/mirror and 0.007 dB/mirror for TE and TM polarizations respectively. A simulation was performed to confirm whether the size of mirror is sufficient to reflect the input light, and to check the quality of the surfaces of fabricated mirrors.

Measuring the Light Dosimetry Within Biological Tissue Using Monte Carlo Simulation (Monte Csrlo 시뮬레이션을 이용한 생체조직내의 광선량 측정)

  • 임현수;구철희
    • Journal of Biomedical Engineering Research
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    • v.20 no.2
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    • pp.199-204
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    • 1999
  • As the correct measuring of the light dosimetry in biological tissues give the important affection to the effect of PDT treatment we used Monte Carlo simulation to measure the light dosimetry on this study. The parameters using in experiments are the optical properties of the real biological tissue, and we used Henyey-Greenstein phase function among the phase functions. As we results, we displayed the result the change of Fluence rate and the difference against the previous theory was at least 0.35%. Biological tissues using in experiment were Human tissue, pig tissue, rat liver tissue and rabbit muscle tissue. The most of biological tissue have big scattering coefficient in visible wavelength which influences penetration depth. The penetration depth of human tissue in visible region is 1.5~2cm. We showed that it is possible to measure fluence rate and penetration depth within the biological tissues by Monte Carlo simulation very well.

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In vitro Propagation of Transgenic Ginsengs Introduced with Ferritin Light Heavy Chain Gene through Single Embryo Culture (Ferritin Light Heavy Chain 유전자가 도입된 인삼형질전환체의 단일배발생을 통한 식물체의 기내증식)

  • 윤영상;김종학;김무성;양덕춘
    • Korean Journal of Plant Resources
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    • v.17 no.2
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    • pp.161-168
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    • 2004
  • Optimal regeneration conditions of ginseng transformants were studied. It has been known that Ferritin Light Heavy Chain (FLHC) gene remove the several heavy metal by combination, store and transport. To obtain the ginseng tolerant to heavy metal, binary vector was introduced in Agrobacterium by tri-parental mating and then Agrobacterium tumefaciens MP90/FLHC was selected on the AB media and MS media containing kanamycin. Explants were co-cultured with Agrobacterium tumefaciens MP90/FLHC, which contained NPT II as a selectable marker, tadpole ferritin heavy chain (FLHC) gene and human ferritin light chain gene and then a number of embryos were induced. The induced embryo transferred to shooting media consisting of MS medium supplemented with GA 10 mg/L. As a result of examination that induced the normal growth of transfomants, transformants showed the equivalent growth in both root and shoot on the media containing the 1/3 MS.

Modeling and Motion-control for a Light-weight Delta Robot (경량 델타로봇의 모델링 및 모션 제어)

  • Kim, Seong-Il;Hong, Jun-Ho;Shin, Dongwon
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.17 no.3
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    • pp.155-162
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    • 2018
  • Delta robots are usually used for industrial manufacturing, but heavy weight and expensive price have been obstacles to rapid propagation of robots in the field. The goal of this research is to make light-weight and price-competitive delta robots. To reduce the weight, we used plastic material for the arm link, and to reduce the price, we used a step-motor as the main actuator. First we formulated the equations of inverse kinematics for the designed delta robot and then verified these equations by using multibody-dynamics simulation. An algorithm of motion control was developed and applied to the motion-processing unit using a timer-interrupt of 8 milliseconds. Finally, we tested the performance of the new delta robot by checking its control of motion along line segments.