• Journal of the Korea Furniture Society
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• v.18 no.3
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• pp.243-247
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• 2007

An experiment was conducted to observe the safranine penetration depth in radial directions of Populus tomentiglandulosa. Radial penetration was considered from bark to pith. In radial direction, ray parenchyma and intercellular space were considered for the measurement of safranine penetration depth. It was found that sapwood conducted safranine 24.23% higher in radial direction compared with heartwood. Intercellular space conducted safranine 39.27% higher depth compared with ray parenchyma and the penetration depth was 39.41% higher in sapwood compared to heartwood. During safranine penetration, it formed a curvature in the lumen of ray parenchyma. Initially safranine penetration was found high and decreased gradually.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.687-689
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• 2003

High resolution satellite images have huge amount of pixels in common. Thus, an efficient method is required for the generation of orthoimages. Patch backprojection method is a feasible way to improve the efficiency with respect to the point-by-point patch backprojection. We will propose an Adaptive Patch that optimizes the patch size for different terrain variations. The essence of the patch optimization is quadrate structuring for terrain variations. The area of interest is, thus, sequentially subdivided to four quadrate tiles until a preset criterion is met. The experiment results indicated that the proposed method is efficient without losing accuracy.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.57-59
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• 2003

Digital surface model generation from IKONOS stereo imagery is a new challenge in photogrammetric community, especially when the satellite company does not provide the raw data as well as their ancillary ephemeris data. In this paper we utilized an estimated relief displacement azimuth and the nominal collection elevation data included in the metadata file to correct the relief displacement of GCPs, together with a linear transformation for geometric modeling of IKONOS imagery. Space intersection is performed by the trigonometric intersection assuming a parallel projection of IKONOS imagery due to its small FOV and frame size. In the experiment, less than 2-meters of RMSE in orbit modeling is achieved denoting the potential positioning accuracy of the IKONOS stereo imagery.

• Journal of the Optical Society of Korea
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• v.9 no.3
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• pp.111-118
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• 2005

In this paper, a new optical parallel binary arithmetic processor (OPBAP) capable of computing arbitrary n-bit look-ahead carry full-addition is proposed and implemented. The conventional Boolean algebra is considered to implement OPBAP by using two schemes of optical logic processor. One is space-variant optical logic gate processor (SVOLGP), the other is shadow-casting optical logic array processor (SCOLAP). SVOLGP can process logical AND and OR operations different in space simultaneously by using free-space interconnection logic filters, while SCOLAP can perform any possible 16 Boolean logic function by using spatial instruction-control filter. A dual-rail encoding method is adopted because the complement of an input is needed in arithmetic process. Experiment on OPBAP for an 8-bit look-ahead carry full addition is performed. The experimental results have shown that the proposed OPBAP has a capability of optical look-ahead carry full-addition with high computing speed regardless of the data length.

• Journal of Auto-vehicle Safety Association
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• v.13 no.4
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• pp.73-80
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• 2021

Recently, Korea has established a plan for the supply of hydrogen vehicles and is promoting the expansion of the supply. Risk factors for hydrogen vehicles are hydrogen leakage, jet fire, and explosion. Therefore Safety measures are necessary for this hazard. In addition, risks in semi-closed spaces such as tunnels, underground roads, and underground parking lots should be analyzed. In this study, an explosion experiment was conducted on a hydrogen tank used in a hydrogen vehicle to analyze the risk of a hydrogen vehicle explosion accident that may occur in a semi-closed space. As results, the effect on the structure and the human body was analyzed using the overpressure and impulse values for each distance generated during the explosion.

• IEMEK Journal of Embedded Systems and Applications
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• v.17 no.6
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• pp.347-353
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• 2022

In this paper, we propose a method that performs a text-video retrieval model by replacing video properties using captions. In general, the exisiting embedding-based models consist of both joint embedding space construction and the CNN-based video encoding process, which requires a lot of computation in the training as well as the inference process. To overcome this problem, we introduce a video-captioning module to replace the visual property of video with captions generated by the video-captioning module. To be specific, we adopt the caption generator that converts candidate videos into captions in the inference process, thereby enabling direct comparison between the text given as a query and candidate videos without joint embedding space. Through the experiment, the proposed model successfully reduces the amount of computation and inference time by skipping the visual processing process and joint embedding space construction on two benchmark dataset, MSR-VTT and VATEX.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.2_1
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• pp.225-230
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• 2023

This research addresses sound command based human tracking problems for autonomous cleaning mobile robot in a networked AI space. To solve the problem, the difference among the traveling times of the sound command to each of three microphones has been used to calculate the distance and orientation of the sound from the cleaning mobile robot, which carries the microphone array. The cross-correlation between two signals has been applied for detecting the time difference between two signals, which provides reliable and precise value of the time difference compared to the conventional methods. To generate the tracking direction to the sound command, fuzzy rules are applied and the results are used to control the cleaning mobile robot in a real-time. Finally the experiment results show that the proposed algorithm works well, even though the mobile robot knows little about the environment.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.58.4-59
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• 2021

This presentation introduces Korea's SNIPE (Small scale magNespheric and Ionospheric Plasma Experiment) mission, formation flying CubeSat constellation. Observing particles and waves on a single satellite suffers from inherent space-time ambiguity. To observe spatial and temporal variations of the micro-scale plasma structures on the topside ionosphere, four 6U CubeSats (~ 10 kg) will be launched into a polar orbit of the altitude of ~500 km in 2021. The distances of each satellite will be controlled from 10 km to more than 100 km by formation flying algorithm. The SNIPE mission is equipped with identical scientific instruments, solid-state telescope, magnetometer, and Langmuir probe. All the payloads have a high temporal resolution (sampling rates of about 10 Hz). Iridium modules provide an opportunity to upload changes in operational modes when geomagnetic storms occur. SNIPE's observations of the dimensions, occurrence rates, amplitudes, and spatiotemporal evolution of polar cap patches, field-aligned currents (FAC), radiation belt microbursts, and equatorial and mid-latitude plasma blobs and bubbles will determine their significance to the solar wind-magnetosphere-ionosphere interaction and quantify their impact on space weather.

• Publications of The Korean Astronomical Society
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• v.23 no.2
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• pp.73-90
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• 2008

A software simulator is developed for verifying the VLBI Correlation Subsystem (VCS) trial product hardware. This software simulator includes the delay tracking, fringe rotation, bit-jump, FFT analysis, re-quantization, and auto/cross-correlation functions so as to confirm the function of the VCS trial product hardware. To verify the effectiveness of the developed software simulator, we carried out experiments using the simulation data which is a mixed signal with white noise and tone signal generated by software. We confirmed that the performance of this software simulator is similar as that of the hardware system. In case of spectral analysis and re-quantization experiment, a serious problem of the VCS hardware, which is not enough for expressing the data stream of FFT results specified in VCS hardware specification, was found by this software simulator. Through the experiments, the performance of software simulator was verified to be efficient. In future, we will improve and modify the function of software simulator to be used as a software correlator of Korea-Japan Joint VLBI Correlator (KJJVC).

• Journal of Science and Technology Studies
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• v.9 no.1
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• pp.89-127
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• 2009

The Korean Astronaut Project(KAP) aims to make the first Korean astronaut fly and take part in space activities in the International Space Station(ISS) in April 2008. KAP was on the purpose of studying the requirement to master manned space technologies as part of the long-term basic plan for national space development. However, people criticized that Ms. Yi was a 'space tourist' not an 'astronaut' because KAP was a program for pride, prestige in 21c's new space race, not specifically science and technology. The government emphasized that Yi carried out her 15 experiments in ISS very competently. In contrast people devaluated Yi's space experiments as below the level, though some of them are enough meaningful to be published on SCI journals. Why did the government fail to make people take Ms. Yi as an astronaut? I answer to this question using the notion of "Network Analysis" based on Actor-Network Theory(ANT).