• Journal of the Korea Society of Computer and Information
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• v.27 no.7
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• pp.49-55
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• 2022

In this paper, we propose an obstacle detection method that can operate robustly even in external environmental factors such as weather. In particular, we propose an obstacle detection system that can accurately inform dangerous situations in AR through DB-based feature matching and RANSAC-based multiplane method. Since the approach to detecting obstacles based on images obtained by RGB cameras relies on images, the feature detection according to lighting is inaccurate, and it becomes difficult to detect obstacles because they are affected by lighting, natural light, or weather. In addition, it causes a large error in detecting obstacles on a number of planes generated due to complex terrain. To alleviate this problem, this paper efficiently and accurately detects obstacles regardless of lighting through DB-based feature matching. In addition, a criterion for classifying feature points is newly calculated by normalizing multiple planes to a single plane through RANSAC. As a result, the proposed method can efficiently detect obstacles regardless of lighting, natural light, and weather, and it is expected that it can be used to secure user safety because it can reliably detect surfaces in high and low or other terrains. In the proposed method, most of the experimental results on mobile devices reliably recognized indoor/outdoor obstacles.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.4
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• pp.45-52
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• 2000

We present a novel method for simple and efficient analysis of the rectangular MQW waveguide. Preferentially two-dimensional structure is transformed into one-dimensional structure by using the effective index method. Then, the characteristic matrix of the resultant planar MQW waveguide is analyzed by scanning angle method. The effective index, modal intensity, and optical confinement factor of rectangular MQW waveguide can be effectively obtained by this method. Our simulation results show excellent agreement with the accurate solutions based on the finite element method. We also introduce the approximation methods for the analysis of rectangular MQW waveguide and investigate their validity. By using perturbation approach, modal power loss of guided wave in rectangular MQW waveguide is newly investigated and compared with the conventional method using the approximation of planar MQW waveguide.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.12
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• pp.2364-2375
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• 1994

For the efficient recognition of printed Korean characters, a multiplexed minimum average correlation energy(MMACE) filter is proposed. Proposed method solved the disadvantages of the tree structure algorithm which recognition system is very huge and recognition method is sophisticated. Using only one consonant MMACE filter and one vowel one, we recognized the full Korean character. Each MMACE filter is multiplexed by 4 K-tuple MACE filters which are synthesized by 24 consonants and vowels. Hence the proposed MMACE filter and the correlation distribution plane are divided by 4 subregion. We obtained the binary codes for the Korean character recognition from each correlation distribution subplane. And the obtained codes are compared with the truth table for consonants and vowels in computer. We can recognize the full Korean characters when substitute the corresponded consonant or vowel font of the consistent code to the correlation peak place in the output correlation plane. The computer simulation and optical experiment results show that the proposed compact Korean character recognition system using the MMACE filters has high discrimination capability.

• Journal of Korea Water Resources Association
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• v.32 no.2
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• pp.153-162
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• 1999

In this study, mixing and dilution characteristics of vertical multijet discharged by multiport diffuser into stagnant water are investigated. The results obtained from the experiment of multiport diffuser performed in the three dimensional flume are as follows. As far as merging process of multiport diffuser is concerned, merging starts at about z/l = 3 although merging length is dependent upon stability condition and thereafter lateral temperature distribution becomes gradually uniform which is typical distribution of plane jet. Analyses of experimental data for minimum dilution show that characteristics of minimum dilution are described based on three regions which are jet region where momentum is dominated, intermediate region, and plume region where buoyancy is dominated. Minimum dilution coefficient in plume region of multiport diffuser obtained in this study is 15% higher than that of plane diffuser. This is because individual jet of multiport diffuser entrains more ambient water before merging is occurred, and therefore dilution increases.

• Journal of Korean Society for Geospatial Information Science
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• v.19 no.4
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• pp.109-118
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• 2011

In this research estimated accuracies that were results in all the area of filtering of the plane equation that was used by whole data set, and regional of filtering that was driven by the plane equation for each vertual Grid. All of this estimates were based by all the area of filtering that deduced the plane equation by multiple linear regression analysis that was used by ground data set. Therefore, accuracy of all the area of filtering that used whole data set has been dropped about 2~3% when average of accuracy of all the area of filtering was based on ground data set while accuracy of Regional of filtering dropped 2~4% when based on virtual Grid. Moreover, as virtual Grid which was set 3~4 cm was difference about 2% of accuracy from standard data. Thus, it leads conclusion of set 3~4 times bigger size in virtual Grid filtering over LiDAR scan gap will be more appropriated. Hence, the result of this research allow us to conclude that there was difference in average accuracy has been noticed when we applied each different approaches, I strongly suggest that it need to research more about real topography for further filtering accuracy.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.433-434
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• 2018

본 논문에서는 개발한 가상현실 게임의 소개와 적용기술에 대하여 서술하였다. 가상현실(Virtual Reality, VR) 게임은 기존의 게임과는 다른 몰입도와 평면을 넘은 가상의 공간, 활동적인 액션의 이점을 가지고 있고 사람들과 같이 활동적인 플레이를 더하기 위해 다중사용자 환경의 기반을 구현하고, 좀 더 활동적인 다중사용자 환경으로 만들기 위해 서로 경쟁하는 사격게임과 같이 협력하여 플레이해 나가는 디펜스게임을 개발하였다. 개발도구로는 에픽 게임스의 언리얼 엔진4 v4.19.2을 개발엔진으로 활용하였고, HTC Vive의 VR장비와 컨트롤러를 사용하여 다중사용자를 위한 VR 게임 콘텐츠를 개발하였다.

• Defense and Technology
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• no.9 s.283
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• pp.66-73
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• 2002

대부분의 현대 항공기 조종실은 유사한 형태인 HUD, 2개 이상의 MFD, UFC, HOTAS 등으로 구성된다. 앞에서 언급한 바와 같이 최근에는 전투기에도 HMD와 DVI(Direct Voice Input)를 적용하고 있다. 미래의 조종실은 빠르게 발전하고 있는 평면 시현 기술로 인해 HDD는 2010년대에는 15 X 20인치 크기까지 지원이 가능할 것으로 예상되며 HUD가 없어지고 높은 해상도가 넓은 시계영역을 가진 HMD가 없어지고 높은 해상도와 넓은 시계영역을 가진 HMD로 다중 운용(Joing Service Operability) 및 다중 임무 수행이 가능한 조종실이 될 것이며 2025년대에는 레이저 운용에 적합한 조종실로 변화되어 캐노피가 없는 조종실(Windowless Codkpit) 또는 불투명 HMD를 사용한 설계개념으로 발전할 것이다.

• Korean Journal of Applied Biomechanics
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• v.19 no.1
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• pp.59-66
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• 2009

The purpose of this study was to evaluate flatness of swing plane and determine swing plane type using 3-D swing plane analysis from young elite male golf players. This study also investigate the possibility of determination of swing plane using other kinematic parameters except flatness. As results, no correlations was found between flatness and handicap. Comparison of flatness between single plane and multiple plane swing group were performed and found a significant difference. The error range of flatness, 10cm, which was used for distinguish swing plane type was effective since significant differences were found at MB, EB, and EF. These differences were typical characteristics to classify two swing styles. Other kinematic parameters such as unit vector components of shaft and displacement of shaft end point also compared per event but found no significant differences. However, the moving patterns of these parameters during a golf swing showed such characteristics of each swing plane type well that these parameters could be used to determine swing style as an indirect barometers.

• Proceedings of the Optical Society of Korea Conference
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• 2005.07a
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• pp.152-153
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• 2005

• Tunnel and Underground Space
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• v.22 no.5
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• pp.346-353
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• 2012

Multi-specimen uniaxial compression test has been carried out in order to find the method to determine the five independent elastic constants from a single standard specimen of a transversely isotropic rock. Total 35 specimens of 7 different angles from a large block of rhyolite presenting the flow structure obviously are used in tests. This second report is to focus on the statistical evaluation of measured strains and analyzed elastic constants. And the determination of their true or near-true values is discussed. As the result of RSD analysis, it turns out that the reliability of measured strains is sufficiently obtained and Saint-Venant approximation is well applicable except 15 degree angled specimen in tests. RSD is decreasing on the increase of the angle of anisotropy. This tendency may be caused not only by the decreasing of the deviation of measured strains, but also by the better applicability of Saint-Venant approximation on the increase of angle. It can be concluded that the analyzed values are considered the near-true ones of five independent constants on the high reliability. But the variation of the apparent Young's modulus expected by these values is not proved to match the measured tendency. It is inferred that the factor to decrease the apparent Young's modulus and/or to increase the shear strain, is present in the test or in the nature of the anisotropy in consideration of this inconsistency.