• Title/Summary/Keyword: Background current

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A Study on Prototype Hybrid (LTS/HTS) Magnet for NMR Application

  • Choi, Suk-Jin;Hwang, Young-Jin;Ko, Tae-Kuk
    • Journal of Magnetics
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    • v.16 no.3
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    • pp.312-317
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    • 2011
  • NMR over 1 GHz (23.5 T) level has difficulties in design and fabrication with only low temperature superconducting (LTS) wire because of its material characteristics such as the decay of critical current under the magnetic field. Because High temperature superconducting (HTS) tape has a good performance under the extremely high magnetic field, it has been developed for high-field magnet over 23.5 T. In this paper, the LTS magnet was made for applying magnetic fields externally and the HTS coil was designed and fabricated. The electromagnetic field analysis has been done with respect to the structure and the operating current of the LTS and HTS coil. Considering to the field homogeneity and the center field, the design parameters which is suitable for the HTS coil were found. The HTS insert coil was impregnated with epoxy resin in order to prevent the movement of winding during energizing the magnet. The hybrid magnet (LTS/HTS) magnet was fabricated and tested based on the design parameters. The experimental result shows that the LTS background magnet and the HTS insert coil can be operated stable beyond 220 A and 210 A. The final value 4.32 T at the center was acquired.

Data Augmentation Scheme for Semi-Supervised Video Object Segmentation (준지도 비디오 객체 분할 기술을 위한 데이터 증강 기법)

  • Kim, Hojin;Kim, Dongheyon;Kim, Jeonghoon;Im, Sunghoon
    • Journal of Broadcast Engineering
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    • v.27 no.1
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    • pp.13-19
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    • 2022
  • Video Object Segmentation (VOS) task requires an amount of labeled sequence data, which limits the performance of the current VOS methods trained with public datasets. In this paper, we propose two effective data augmentation schemes for VOS. The first augmentation method is to swap the background segment to the background from another image, and the other method is to play the sequence in reverse. The two augmentation schemes for VOS enable the current VOS methods to robustly predict the segmentation labels and improve the performance of VOS.

Object Tracking And Elimination Using Lod Edge Maps Generated from Modified Canny Edge Maps (수정된 캐니 에지 맵으로부터 만들어진 LOD 에지 맵을 이용한 물체 추적 및 소거)

  • Park, Ji-Hun;Jang, Yung-Dae;Lee, Dong-Hun;Lee, Jong-Kwan;Ham, Mi-Ok
    • The KIPS Transactions:PartB
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    • v.14B no.3 s.113
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    • pp.171-182
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    • 2007
  • We propose a simple method for tracking a nonparameterized subject contour in a single video stream with a moving camera and changing background. Then we present a method to eliminate the tracked contour object by replacing with the background scene we get from other frame. First we track the object using LOD (Level-of-Detail) canny edge maps, then we generate background of each image frame and replace the tracked object in a scene by a background image from other frame that is not occluded by the tracked object. Our tracking method is based on level-of-detail (LOD) modified Canny edge maps and graph-based routing operations on the LOD maps. We get more edge pixels along LOD hierarchy. Our accurate tracking is based on reducing effects from irrelevant edges by selecting the stronger edge pixels, thereby relying on the current frame edge pixel as much as possible. The first frame background scene is determined by camera motion, camera movement between two image frames, and other background scenes are computed from the previous background scenes. The computed background scenes are used to eliminate the tracked object from the scene. In order to remove the tracked object, we generate approximated background for the first frame. Background images for subsequent frames are based on the first frame background or previous frame images. This approach is based on computing camera motion. Our experimental results show that our method works nice for moderate camera movement with small object shape changes.

Relationship between Reading Speed and Blinking Rate according to Longitudinal Chromatic Aberration during Book Reading (종이책 독서 시 종색수차에 따른 읽기속도와 순목횟수의 상관관계)

  • Kim, Se-il;Park, Mijung;Kim, So Ra
    • Journal of Korean Ophthalmic Optics Society
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    • v.20 no.3
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    • pp.369-375
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    • 2015
  • Purpose: The current study was performed to estimate the changes in reading speed and blinking rate according to different background colors when reading paper book and further investigate their correlation. Methods: Twenty-nine adults (10 males, 19 females) who consented to the present study and had no ocular disease, ocular surgery history showing normal binocular vision were participated into the study. The subjects were asked to read the novels with black letter printed on white, red, green and blue background for 15 min, respectively. Then, the reading speed per page and blinking rate per page were measured during reading and analyzed according to background colors. Results: Reading speed per page according to the background color showed a tendency to accelerate in the white and green background as the reading time increased however, it was almost unchanged in the blue background and rather decelerated in the red background. On the other hand, the blinking rate per page tended to decrease in all background as the reading time was increased however, the smallest reduction was shown in the red background. There was a correlation that the reading speed increased as the blinking rate decreased in all backgrounds and the best correlation was shown in the green background. Conclusions: From the results, a correlation between the increasing reading speed and the reducing blinking rate while reading paper book with same demand on accommodation and convergence was confirmed however, the change in blinking rate and reading speed was varied depending on the main wavelength of light. It might mean that the working speed and visual fatigue can be varied depending on the difference of main wavelength when doing near work. Thus, it can be suggested that the adjustment of working environment and conditions should be made according to the kind of required perception.

Modeling of Heart Phantom using the Multidipole Current Source

  • Jang, Kwan-Hee;Yoon, Dal-Hwan;Min, Seung-Gi
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.1957-1962
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    • 2003
  • In order to design the phantom of heart, we have developed the multi-dipole current source system. Such a one be clue to the various motion of heart. The magnetocardiograph (MCG) system for diagnosing the disease of the heart due to an analysis of the heart signal. The multidipole current source system be built by microprocessor. We use the shield room to obtain a good experimental result. Then the signal acquired is mixed with a background noise, through a filtering extracts a pure signal. The pure signal such a heart phantom is analyzed by an electromagnetic map.

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Development of Sheet Metal Forming Apparatus Using Electromagnetic Lorentz Force (전자기 로렌쯔력을 이용한 박판성형 장비 개발)

  • Lee, H.M.;Kang, B.S.;Kim, J.
    • Transactions of Materials Processing
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    • v.19 no.1
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    • pp.38-43
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    • 2010
  • Electromagnetic forming (EMF) method is one of high-velocity forming processes, which uses electromagnetic Lorentz force. Advantages of this forming technique are summarized as improvement of formability, reduction in wrinkling, non-contact forming and applications of various forming process. In this study, the EMF apparatus is developed. It is designed to be stored in 10 capacitors connected in parallel, each with a capacitance of $50{\mu}F$ and maximum working voltage of 5kV. The system has capacitance of $500{\mu}F$ and maximum stored energy of 6.25kJ. And EMF experiments are carried out to verify the feasibility of the EMF apparatus, which has enough forming force from the results of EMF experiment. In addition, peak current carrying a forming coil is predicted from theoretical background, and verified the predicted value compared with experimental value using the current measurement equipment. Consequently, EMF apparatus developed in this study can be applied to various EMF researches for commercialization.

A Study on the Development of Civil Aviation Industry and Civil Aviation Law of China (항공운송산업 발전에 따른 중국 민용항공법의 문제점 및 개선방향에 대한 고찰)

  • Park, Myoung-Sup;Chen, Zhen-Ghui;Yun, Jae-Ho
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.42
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    • pp.211-245
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    • 2009
  • In this paper we firstly review the developmental stages of the Chinese civil aviation industry since 1949 and the background history of the Chinese Civil Aviation Law of 1996. We secondly analyzed the main terms and conditions about the Chinese civil aviation law and pointed out several problematic issues in view of the development of the Chinese aviation industry. Current civil aviation law in China has been in effect for the last 12 years. In these periods, Chinese civil aviation industry has developed in a high speed and great changes have occurred in its market environments. Thus, some of the terms and conditions in current civil aviation law in China have become outdated and unsuitable for the current developmental stage of the Chinese civil aviation industry. Therefore, we proposed some directions of the future amending of the Chinese Civil Aviation Law.

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CIRCUIT MODEL SIMULATION FOR IONOSPHERIC PLASMA RESPONSE TO HIGH POTENTIAL SYSTEM

  • Rhee, Hwang-Jae;Raitt, W.-John
    • Journal of Astronomy and Space Sciences
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    • v.17 no.1
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    • pp.99-106
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    • 2000
  • When a deployed probe is biased by a high positive potential during a space experiment, the payload is induced to a negative voltage in order to balance the total current in the whole system. The return currents are due to the responding ions and secondary electrons on the payload surface. In order to understand the current collection mechanism, the process was simulated with a combination of resistor, inductor, and capacitor in SPICE program which was equivalent to the background plasma sheath. The simulation results were compared with experimental results from SPEAR-3 (Space Power Experiment Aboard Rocket-3). The return current curve in the simulation was compatible to the experimental result, and the simulation helped to predict the transient plasma response to a high voltage during the plasma sheath formation.

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Rural Residents' Demand for Rural Rent-House (농촌 임대주택에 대한 요인별 입주의사 분석)

  • Park, Yoon-Ho;Koo, Seung-Mo;Lee, Han-Sung
    • Korean Journal of Agricultural Science
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    • v.37 no.1
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    • pp.151-160
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    • 2010
  • Housing is one of the most important factors determining the quality of rural life. Housing condition in rural area has been deteriorating over the past years in spite of many rural development programs. Korean government formulated 'Rural Housing Environment Improving Plan' including rural rent-house program in 2006. This study aims to find the fundamental intension of rural people for adopting the rent-house system in rural area. To do this, background and current state of rural rent-house program are presented and the demand for rural rent-house is analyzed based on the survey results done by Korea Rural Community Corporation in 2005. Major findings from the survey analysis imply that the size/age/ownership of the current houses and the age of householders, motive and time period of current residing, and components of households are significant factors when considering whether they are willing to apply rural rent-house.

A Note on the Outflow Boundary Conditions in Modeling the East Sea Circulation

  • Seung, Young-Ho;Cho, Kyoung-Ho
    • Journal of the korean society of oceanography
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    • v.33 no.4
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    • pp.212-218
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    • 1998
  • Three different outflow boundary conditions are considered in modeling the East Sea circulation. The first one is that of the conventional constant volume transport (CT). The second one is the Orlanski radiation boundary condition (OR). The third one is that of the constant sea level just outside the outflow boundary (SL). In the third condition, the outflow current is set to be driven by the sea level differences across the outflow open-boundary lines, based on the recent knowledge that the Tsushima Current is driven by the sea level differences across the inflow and outflow boundaries. In case of OR it takes too much time to reach the steady state, resulting in a large increase of Tsushima Current Water in the basin and low level of kinetic energy. Both CT and SL reach the steady state in a relatively short time. However, SL is more recommendable, because it is based on physical background and generates less numerical noises than CT.

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