• Title/Summary/Keyword: Fixing time

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A Study on the Applicability of the Kinematic and the Static GPS Methods for Coastal Ocean Structure Survey

  • Lee, Byung-Gul;Yang, Sung-Kee;Kang, In-Jun
    • Journal of Environmental Science International
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    • v.11 no.2
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    • pp.103-110
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    • 2002
  • The position fixing usually is determined by triangulation, traverse surveying and astronomy surveying. However, when the station is moving, it is impossible to determine its position continuously by the former method. By a satellite positioning method(GPS), this problem can be solved. In our study, we used two methods to determine the length and coordinate of a point position. One is a kinematic GPS method and the other is a static one. Each is based on carrier phase measurement and employs a relative position technique. We implemented observation experiments such as Geodimeter and DGPS(Differential GPS) successfully. To estimate the accuracy between the kinematic and static methods, we compared the results of Geodimeter, the kinematic, and the static. The results showed that the static is relatively a little more accurate than the kinematic. However, in the kinematic mode, when we received the GPS data for a long time, we found that the kinematic also had a high accuracy value for the length survey Finally, we applied the GPS to Jeju Harbor Breakwater to examine the applicability of GPS for coastal ocean structure based on the kinematics and the statics, respectively.

Hybrid Technology using 3D Printing and 5-axis Machining for Development of Prototype of the Eccentric Drive System (편심구동장치 시제품 개발을 위한 3D프린팅-5축가공 복합기술)

  • Hwang, Jong-Dae;Yang, Jun-Seok;Yun, Sung-Hwan;Jung, Yoon-Gyo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.15 no.2
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    • pp.38-45
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    • 2016
  • Since a 5-axis machine tool has two rotary axes, it offers numerous advantages, such as flexible accessibility, longer tool life, better surface finish, and more accuracy. Moreover, it can conduct whole machining by rotating the rotary feed axes while setting the fixture at once without re-fixing in contrast to conventional 3-axis machining. However, it is difficult to produce complicated products that have a hollow shape. In contrast, 3D printing can produce an object with a complicated hollow shape easily and rapidly. However, because of layer thickness and shrinkage, its surface finish and dimensional accuracy are not adequate. Therefore, this study proposes hybrid technology by integrating the advantages of these two manufacturing processes. 3D printing was used as the additive manufacturing rapidly in the whole body, and 5-axis machining was used as the subtractive manufacturing accurately in the joining and driving places. The reliability of the proposed technology was verified through a comparison with conventional technology in the aspects of processing time, surface roughness. and dimensional accuracy.

Molecular Genetics of the Model Legume Medicago truncatula

  • Nam, Young-Woo
    • The Plant Pathology Journal
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    • v.17 no.2
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    • pp.67-70
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    • 2001
  • Medicago truncatula is a diploid legume plant related to the forage crop alfalfa. Recently, it has been chosen as a model species for genomic studies due to its small genome, self-fertility, short generation time, and high transformation efficiency. M. truncatula engages in symbiosis with nitrogen-fixing soil bacterium Rhizobium meliloti. M. truncatula mutants that are defective in nodulation and developmental processes have been generated. Some of these mutants exhibited altered phenotypes in symbiotic responses such as root hair deformation, expression of nodulin genes, and calcium spiking. Thus, the genes controlling these traits are likely to encode functions that are required for Nod-factor signal transduction pathways. To facilitate genome analysis and map-based cloning of symbiotic genes, a bacterial artificial chromosome library was constructed. An efficient polymerase chain reaction-based screening of the library was devised to fasten physical mapping of specific genomic regions. As a genomics approach, comparative mapping revealed high levels of macro- and microsynteny between M. truncatula and other legume genomes. Expressed sequence tags and microarray profiles reflecting the genetic and biochemical events associated with the development and environmental interactions of M. truncatula are assembled in the databases. Together, these genomics programs will help enrich our understanding of the legume biology.

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A Study on the Position Error of the Aids to Navigation as a Safety Factor at Sea (선박 안전항행을 위한 항로표지의 위치오차 분석)

  • Kwon, Hyuk-Dong;Kim, Woong-Gyu;Lee, Joo-Hyung;Park, Gyei-Kark
    • Journal of Advanced Navigation Technology
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    • v.10 no.3
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    • pp.226-234
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    • 2006
  • Aids to Navigation is one of the most important facility for safety at sea. However, in terms of position there always exists discrepancy in inventory by media and/or organizational body who maintains the facility which may result in incredibility for navigator's position fixing or hazard avoidance. This paper suggests two major factors as the causes of the position error when they design, install and survey the aids to navigation. One is the function of direction of tide and water depth which makes swinging circle. The other is a variable value by time resulting from multiple coordination of satellites in contact. This paper aims to minimize inaccuracy by verifying its reason through numerical analysis over inherent position error.

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Study on the Internal Flow of an Electric Oven with Variation of Steam Outlet Position (전기오븐의 스팀 출구위치에 따른 내부유동에 대한 연구)

  • Park, Young Hun;Kim, Yu Jin;Jung, Young Man;Park, Warn-Gyu
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.25 no.8
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    • pp.450-456
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    • 2013
  • The composite electric oven is one of the fixing utensil, various functions are required. Steam generating function, which is one of its functions, and allows various food cooking. The location of the outlet of the steam generator is designed around ease of installation, consideration of internal fluid is not. Distribution of the steam can not be non-uniformly. Accordingly, cooking time becomes longer, the energy consumption increases. As a result of the analysis, it was confirmed stagnation phenomenon of the internal flow through the interpretation of the calculations for the position of the outlet of the steam generator existing. Further, by computing the analysis of various locations of the outlet of the steam generator, we investigated the distribution and characteristics of the internal flow.

Development of 6-Axis Stiffness Measurement Device for Prosthetic Socket Design (의수 소켓 설계를 위한 6축 인체 탄성도 측정 장치 개발)

  • Oh, Donghoon;Lee, Seulah;Choi, Youngjin
    • The Journal of Korea Robotics Society
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    • v.14 no.1
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    • pp.58-64
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    • 2019
  • The paper proposes a stiffness measurement device composed of a measurement part including six indenters and a fixing part including four fixtures. The device is able to make simultaneously measurements of the stiffness of human arm. The six indenters make use of both position and force control schemes sequentially whenever needed. In addition, the loadcells and the digital encoders are attached to the indenters and electric motors, respectively, so that the data can be provided in real time. On the end of the indenter, two-axis potentiometer is attached in order to measure the angle difference between the applied force axis and the axis normal to the skin of human arm, and to convert the force measured on the loadcell into the actual applied force to skin. For this purpose, the mapping between the voltage output and the angle of potentiometer was obtained by fitting it for each axis. Ultimately, the measurement device was able to measure the stiffnesses of six regions of human arm.

Global sensitivity analysis improvement of rotor-bearing system based on the Genetic Based Latine Hypercube Sampling (GBLHS) method

  • Fatehi, Mohammad Reza;Ghanbarzadeh, Afshin;Moradi, Shapour;Hajnayeb, Ali
    • Structural Engineering and Mechanics
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    • v.68 no.5
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    • pp.549-561
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    • 2018
  • Sobol method is applied as a powerful variance decomposition technique in the field of global sensitivity analysis (GSA). The paper is devoted to increase convergence speed of the extracted Sobol indices using a new proposed sampling technique called genetic based Latine hypercube sampling (GBLHS). This technique is indeed an improved version of restricted Latine hypercube sampling (LHS) and the optimization algorithm is inspired from genetic algorithm in a new approach. The new approach is based on the optimization of minimax value of LHS arrays using manipulation of array indices as chromosomes in genetic algorithm. The improved Sobol method is implemented to perform factor prioritization and fixing of an uncertain comprehensive high speed rotor-bearing system. The finite element method is employed for rotor-bearing modeling by considering Eshleman-Eubanks assumption and interaction of axial force on the rotor whirling behavior. The performance of the GBLHS technique are compared with the Monte Carlo Simulation (MCS), LHS and Optimized LHS (Minimax. criteria). Comparison of the GBLHS with other techniques demonstrates its capability for increasing convergence speed of the sensitivity indices and improving computational time of the GSA.

Redefinition of the SI Base Units with Fundamental Constants (기본상수를 이용한 SI 기본단위의 재정의)

  • Lee, Ho Seong
    • Korean Journal of Optics and Photonics
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    • v.30 no.4
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    • pp.133-141
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    • 2019
  • Revision of the International System of Units (SI) in terms of fundamental constants was achieved by the 26th General Conference on Weights and Measures (CGPM) in November 2018. Four base units (kilogram, ampere, kelvin, and mole) of SI were redefined by fixing the values of the Planck constant h, elementary charge e, Boltzmann constant k, and Avogadro constant $N_A$ respectively. In this paper the scientific principle for redefining the kilogram from the Planck constant with the Kibble balance is explained as an example. The revised SI takes effect on May 20, 2019.

Enhancing Model-based Fault Traceability by Using Similarity between Bug and Commit Information

  • Jung, Dongju;Min, Kyeongsic;Lee, Jung-Won;Lee, Byungjeong
    • Journal of Internet Computing and Services
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    • v.20 no.2
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    • pp.29-37
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    • 2019
  • As software development technology evolves, the quality of software has increased. But software created through sophisticated technology is still defective. The developer will be aware of the defect through a bug report and the reported defect must be fixed as soon as possible for the software to function correctly. It is important to know which component of the program is related to the reported defect and should be fixed. However, even though the developer understands the developed software, the task of tracing faults is a time-consuming task and requires effort. Therefore, if there is a way for developers to support tracing faults, they could fix defects more quickly. Because fixing defects rapidly is a factor of software reliability, fault traceability is essential and an effective method is needed. Therefore, in this paper, we propose a model-based fault traceability enhancement technique by using bug report and commit information and verify the effectiveness of the proposed technique.

An End-to-End Sequence Learning Approach for Text Extraction and Recognition from Scene Image

  • Lalitha, G.;Lavanya, B.
    • International Journal of Computer Science & Network Security
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    • v.22 no.7
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    • pp.220-228
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    • 2022
  • Image always carry useful information, detecting a text from scene images is imperative. The proposed work's purpose is to recognize scene text image, example boarding image kept on highways. Scene text detection on highways boarding's plays a vital role in road safety measures. At initial stage applying preprocessing techniques to the image is to sharpen and improve the features exist in the image. Likely, morphological operator were applied on images to remove the close gaps exists between objects. Here we proposed a two phase algorithm for extracting and recognizing text from scene images. In phase I text from scenery image is extracted by applying various image preprocessing techniques like blurring, erosion, tophat followed by applying thresholding, morphological gradient and by fixing kernel sizes, then canny edge detector is applied to detect the text contained in the scene images. In phase II text from scenery image recognized using MSER (Maximally Stable Extremal Region) and OCR; Proposed work aimed to detect the text contained in the scenery images from popular dataset repositories SVT, ICDAR 2003, MSRA-TD 500; these images were captured at various illumination and angles. Proposed algorithm produces higher accuracy in minimal execution time compared with state-of-the-art methodologies.