• Imaging Science in Dentistry
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• v.54 no.1
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• pp.57-62
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• 2024

Purpose: This report presents a unique case featuring real, ghost, and pseudo-ghost images on the panoramic radiograph of a patient wearing earrings. It also explains the formation of these images in an easy-to-understand manner. Materials and Methods: One real image and two ghost images appeared on each side of a panoramic radiograph of a patient wearing earrings on both sides. Of the two ghost images on each side, one was considered a typical ghost image and the other was considered a ghost-like real image (pseudo-ghost image). The formation zones of the real, double, and ghost images were examined based on the path and angles of the X-ray beam from the Planmeca ProMax. To simulate the pseudo-ghost and typical ghost images on panoramic radiography, a radiopaque marker was affixed to the right mandibular condyle of a dry mandible, and the position of the mandible was adjusted accordingly. Results: The center of rotation of the Planmeca ProMax extended beyond the jaw area, and the area of double image formation also reached beyond the jaw. The radiopaque-marked mandibular condyle, situated in the outwardly extending area of double image formation, exhibited triple images consisting of real, double (pseudo-ghost), and ghost images. These findings helped to explain the image formation associated with the patient's earrings observed in the panoramic radiograph. Conclusion: Dentists must understand the characteristics and principles of the panoramic equipment they use and apply this understanding to taking and interpreting panoramic radiographs.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.38 no.1
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• pp.36-42
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• 2002

This study was conducted to estimate the number of lost or abandoned plastic sea-eel pots and investigate the actual condition on the ghost fishing happened from the pots during the period of August 1996 and January 2002 In the Southern Sea of Korea. The average number of lost or abandoned sea-eel pots in the investigated sea area were 34 ea/$\textrm{km}^2$ and was the lowest as 5 ea/$\textrm{km}^2$ Sea Area code # 113 and was the highest as 94 ea/$\textrm{km}^2$ in the Sea Area code #106. Pots number in accordance with water depth was the highest as 89 ea/$\textrm{km}^2$ on the level of 61 ~70m and there was no collection for the sea-eel pot over 130m water depth. The average catch rate of ghost fishing happened from the lost or abandoned pots was 8.1% and the highest rate was 25% in the Sea Area code #224 and there were no catches in the Sea Area code # 92, 110, 243 and 253. The number of lost or abandoned sea-eel pots continued ghost fishing were estimated as 14.2 ea/$\textrm{km}^2$ in the Sea Area code # 99 and was the highest. Catch rate of ghost fishing according to water depth was the highest as 23.5% on the level of 71~80 m, and the number of lost or abandoned sea-eel pots continued ghost fishing were estimated as 12.7 ea/$\textrm{km}^2$ on the level of 81~90m and was the highest. Length distribution of sea-eel which were caught from ghost fishing was 25.5~66.0$\textrm{cm}^2$

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.05a
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• pp.51-54
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• 2003

Ghost fishing이란 유실되거나 버려진 어구가 바다 속에 방치된 채로 어획을 계속하고 있는 상태를 의미하며, 이것이 주목받게 된 것은 1960년 FAO가 Ghost fishing의 심각성을 지적한 이후이다. 1950년대까지는 어구에 쓰이는 그물이 천연 재료였기 때문에 유실 어구는 일정 기간 후에 바다 속에서 부패되어, 어구로서의 기능을 상실하게 되므로서 Ghost fishing이 크게 문제시되지 않았다. (중략)

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.8
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• pp.412-417
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• 2000

TV ghost interference can be described as passive interference by the conducting part of transmission lines. In order to survey this interference from large-sized overhead EHV (extra high voltage) transmission line, TV reception quality was measured in the vicinity of that before and after construction. Instrumentation system was composed of ghost analyzer, TV received field intensity meter, VHF/UHF antennas, TV monitor and so on. The system is installed inside the vehicle. TV field intensity and PDUR (Perceived Desired wave to Undersired wave Ratio) are measured to evaluate TV ghost by using the system and vehicle. As the results, the useful data, which can be used to evaluate the effect of TV ghost interference from transmission lines could be obtained. In this paper, it is shown that the range of TV ghost interference from transmission lines can vary according to the frequency of TV electromagnetic wave, an incidence angle to the line and the other conditiions. At present, we are making efforts to establish a PDUR guideline for transmission lines.

• Geophysics and Geophysical Exploration
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• v.19 no.4
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• pp.220-227
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• 2016

Marine seismic data have not only primary signals from subsurface but also ghost signals reflected from the sea surface. The ghost decreases temporal resolution of seismic data because it attenuates specific frequency components. For eliminating the ghost signals effectively, the exact ghost delaytimes and reflection coefficients are required. Because of undulation of the sea surface and vertical movements of airguns and streamers, the ghost delaytime varies spatially and randomly while acquiring seismic data. The reflection coefficient is a function of frequency, incidence angle of plane-wave and the sea state. In order to estimate the proper ghost delaytimes considering these characteristics, we compared the ghost delaytimes estimated with L-1 norm, L-2 norm and kurtosis of the deghosted trace and its autocorrelation on synthetic data. L-1 norm of autocorrelation showed a minimal error and the reflection coefficient was calculated using Kirchhoff approximation equation which can handle the effect of wave height. We applied the estimated ghost delaytimes and the calculated reflection coefficients to remove the source and receiver ghost effects. By removing ghost signals, we reconstructed the frequency components attenuated near the notch frequency and produced the migrated stack section with enhanced temporal resolution.

• Current Optics and Photonics
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• v.1 no.5
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• pp.491-499
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• 2017

Ghost imaging offers great potential, with respect to standard imaging, for imaging objects in optically harsh or noisy environments. It can solve the problems that are difficult to solve by conventional imaging techniques. Recently, it has become a hot topic in quantum optics. In this paper, we propose a scheme for ghost imaging based on rosette scanning, named rosette ghost imaging. Sampling a small area sampling instead of the whole object, the instantaneous field of view of rosette scanning is used as the modulation light field in ghost imaging. This scheme reduces energy loss, the number of samples, and the sampling time, while improving the quality of the reconstructed image.

• Current Optics and Photonics
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• v.3 no.3
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• pp.220-226
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• 2019

A novel speckle-shifting ghost imaging (SSGI) technique is proposed in this paper. This method can effectively extract the edge of an unknown object without achieving its clear ghost image beforehand. However, owing to the imaging mechanism of SSGI, the imaging result generally contains serious noise. To solve the problem, we further propose a simple and effective method to remove noise from the speckle-shifting ghost image with a connected-region labeling (CRL) algorithm. In this method, two ghost images of an object are first generated according to SSGI. A threshold and the CRL are then used to remove noise from the imaging results in turn. This method can retrieve a high-quality image of an object with fewer measurements. Numerical simulations are carried out to verify the feasibility and effectiveness.

• Journal of Microbiology and Biotechnology
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• v.19 no.9
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• pp.982-986
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• 2009

For the production of ghost bacteria vaccine to prevent the streptococcal disease in aquaculture fish species, a double cassettes vector was constructed and cloned in Escherichia coli DH5${\alpha}$. Ghost bacteria vaccine production from Escherichia coli DH5${\alpha}$/pHCE-InaN-GAPDH-Ghost 37 SDM (SIG) was maximized at a glucose concentration of 1 g/l, agitation of 300 rpm, and aeration of 1 vvm. The maximal efficiency of ghost bacteria formation was obtained at the mid-exponential phase ($OD_{600}=2.0$) with the concentration of 0.77 g/l for SIG. The molecular mass of GAPDH was detected at 67 kDa with the insoluble fraction, by SDS-PAGE and Western blot. The protective efficacy of ghost bacteria vaccine was evaluated by challenge test using olive flounder. The cumulative mortalities of the positive control, formalin-killed cell (FKC) vaccine, and SIG vaccine immunized groups were 91%, 74%, and 57%, respectively. These results suggest that SIG vaccine showed efficacy as a vaccine and had a higher potential to induce protective antibodies than did FKC vaccine.

• Korean Journal of Optics and Photonics
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• v.16 no.6
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• pp.481-484
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• 2005

Quantum ghost imaging uses quantum mechanically entangled photons to form an image of an object. The quantum ghost image is also obtained by means of classical coincidence measurements with a classically correlated light source[1,2]. In this work we performed classical coincidence imaging experiments with classically correlated beams in their direction of propagation. We observed the ghost interference patterns which were usually made by quantum mechanically entangled states and we also analyze in detail the mechanism of the ghost imaging with classically correlated lights. We made? the classically correlated source with an Ar laser and controlled the direction of the light by a mirror? mounted on a small speaker.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.8
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• pp.27-33
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• 1993

This paper presents a mobile measurement technique of the ghost-flutter caused in mobile television reception. The ghost-flutter is caused by timing variation of the television horizontal synchronizing pulse due to frequency selective fading in a multipath propagation environment. The ghost-flutter can be detected by measuring the dynamic timing variation of horizontal synchronizing pulse. Especially, in this paper, a technique for measuring horizontal synchronizing timing fluctuations which cause the ghost-flutter is developed, using a Rubidium oscillator as a time standard with high stability.