• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2006년도 춘계학술대회 학술발표 논문집 제16권 제1호
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• pp.56-58
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• 2006

Camera calibration in machine vision is the process of determining the intrinsic cameara parameters and the three-dimensional (3D) position and orientation of the camera frame relative to a certain world coordinate system. On the other hand, Takagi-Sugeno-Kang (TSK) fuzzy system is a very popular fuzzy system and approximates any nonlinear function to arbitrary accuracy with only a small number of fuzzy rules. It demonstrates not only nonlinear behavior but also transparent structure. In this paper, we present a novel and simple technique for camera calibration for machine vision using TSK fuzzy model. The proposed method divides the world into some regions according to camera view and uses the clustered 3D geometric knowledge. TSK fuzzy system is employed to estimate the camera parameters by combining partial information into complete 3D information. The experiments are performed to verify the proposed camera calibration.

• 대한기계학회논문집A
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• 제25권3호
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• pp.486-494
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• 2001

This paper presents a real-time multibody vehicle dynamic analysis method using recursive Kanes formulation and suspension composite joints. To shorten the computation time of simulation, relative coordinate system is used and the equations of motion are derived using recursive Kanes formulation. Typical suspension systems of vehicles such as MacPherson strut suspension system is modeled by suspension composite joints. The joints are derived and utilized to reduce the computation time of simulation without any degradation of kinematical accuracy of the suspension systems. Using the develop program, a multibody vehicle dynamic model is formed and simulations are performed. Accuracy of the simulation results is compared to the real vehicle field test results. It is found that the simulation results using the proposed method are very accurate and real-time simulation is achieved on a computer with single PowerPC 604 processor.

• 터널과지하공간
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• 제21권3호
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• pp.174-180
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• 2011

횡등방성 암석의 강도해석에 활용할 목적으로 이방성 Mohr-Coulomb 파괴조건식을 제안하였다. 제안된 파괴조건식에서는 Pietruszczak & Mroz(2001)가 제안한 조직텐서를 도입하여 마찰각과 점착력을 조직텐서의 스칼라함수로 정의하였다. 두 강도정수의 이방성은 주응력좌표계와 재료 주좌표계의 상대적 회전을 바탕으로 계산된다. 이방성 파괴조건식을 최대로 하는 임계면을 찾는 방법이 Lagrange 승수법에 기초하여 제안되었다. 수치삼축압축 시험을 실시한 후 삼축압축강도와 파괴면 경사각 분석을 통하여 제안된 이방성 파괴함수의 성능을 검증하였다.

• 한국지능시스템학회논문지
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• 제20권2호
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• pp.298-303
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• 2010

로봇은 무선센서를 이용하여 상대 로봇의 위치를 확인한다. 그로인해 자신의 이동방법을 결정하고, 이를 통해 임의위치의 이동 로봇들이 일렬종대와 횡대, 여러 집합모양, 원모양등 여러 가지 형태의 로봇집단을 형성 할 수 있을 것이다. 이러한 로봇집단 형성은 무인 잠수함이나 무인 탱크의 배치계획, 침입자에 대한 포위진형 계획 등에 이용될 것이다. 본 논문은 기반 시설이 필요 없는 군집로봇의 상호위치인식시스템에 대해 다루고 있다. 그러므로 기준점의 좌표 값을 알 필요 없는 삼변측량을 이용하여 상대좌표계에서의 로봇 간 상호위치를 인식한다. 위치탐지를 위한 주요센서로는 초음파, 적외선, 레이저, RFID, 카메라 센서 등을 들 수 있다. 이들 센서들의 정확도는 전파 수단 및 사람, 초목, 건물 등 주위 환경변화에 민감하다. 본 논문에서는 위치추정의 정확도를 높이기 위해 파티클 필터를 제안한다.

• International Journal of Precision Engineering and Manufacturing
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• 제9권2호
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• pp.69-74
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• 2008

Robotics and artificial intelligence are components of IT that involve networks, electrical and electronic engineering, and wireless communication. We consider an algorithm for efficient navigation by building a precise map in a multi-robot system under conditions of limited and unlimited communications. The basis of the navigation algorithm described in this paper is a wave algorithm, which is effective in obtaining an accurate map. Each robot in a multi-robot system has its own task such as building a map for its local position. By combining their data into a shared map, the robots can actively seek to verify their relative locations. Using shared maps, they coordinate their exploration strategies to maximize exploration efficiency. To prove the efficiency of the proposed technique, we compared the final results with the results in $Burgard^{8}$ and $Stachniss.^{9-10}$ All of the simulation comparisons, which are shown as graphs, were made in four different environments.

• Bulletin of the Korean Chemical Society
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• 제35권1호
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• pp.189-196
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• 2014

Water dispersible ZnS based nanocrystals: ZnS (blue), ZnS:Cu (green) and ZnS:Mn (yellow-orange) were synthesized by capping the surface of the nanocrystals with a mercaptopropionic acid (MPA) molecule. The MPA capped ZnS based nanocrystal powders were characterized by using XRD, HR-TEM, EDXS, FT-IR, and FT-Raman spectroscopy. The optical properties of the colloidal nanocrystals were also measured by UV/Vis and photoluminescence (PL) spectroscopies in aqueous solvents. The PL spectra showed broad emission peaks at 440 nm (ZnS), 510 nm (ZnS:Cu) and 600 nm (ZnS:Mn), with relative PL efficiencies in the range of 4.38% to 7.20% compared to a reference organic dye. The measured average particle sizes from the HR-TEM images were in the range of 4.5 to 5.0 nm. White light emission was obtained by mixing these three nanocrystals at a molar ratio of 20 (ZnS):1 (ZnS:Cu):2 (ZnS:Mn) in water. The measured color coordinate of the white light was (0.31, 0.34) in the CIE chromaticity diagram, and the color temperature was 5527 K.

• 한국환경과학회지
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• 제11권2호
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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.

• 한국재료학회지
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• 제12권1호
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• pp.21-26
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• 2002

In order to search new phosphors for plasma display panel(PDP), phosphate hosts which has a host excitation band at around 150nm were prepared and their luminescent properties were investigated. In the preparation of $YPO_4: Eu\; and\; (Y,Gd)PO_4: Eu$ phosphors, the effect of oxide and oxalate starting materials on prepared phosphors were compared in terms of relative emission intensities and particle characteristics. The results showed that oxalate starting materials gave better performance in emission intensities and smaller size and more round shape phosphors which would be more applicable for high resolution display. Additionally, Gd, V, Nb and Ta ions were doped to $YPO_4:Eu$ and the luminescent properties of the resulant solid solutions were investigated to find efficient sensitizer. Among these ions, Gd, V and Nb ions increased the emission intensities of parent phosphor to around 10%. While Nb ion gave the best result in emission intensities, CIE color coordinate were improved by doping V ion into $YPO_4:Eu$ phosphor to give x=0.6523, y=0.3406 compared to commercial sample.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.385-390
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• 2003

Shape of a multi-blades centrifugal fan is optimized by response surface method based on three-dimensional Navier-Stokes analysis. For numerical analysis, Reynolds-averaged Wavier-Stokes equations with standard $k-{\varepsilon}$ turbulence model are transformed into non-orthogonal curvilinear coordinate system, and are discretized with finite volume approximations. Due to the large number of blades in this centrifugal fan, the flow inside of the fan is regarded as steady flow by introducing the impeller force models for economic calculations. Optimizations with and without constraints are carried out. Design variables, location of cur off, radius of cut off, expansion angle of scroll and width of impeller were selected to optimize the shapes of scroll and blades. Data points for response evaluations were selected by D-optimal design, and linear programming method was used for the optimization on the response surface. As a main result of the optimization, the efficiency was successfully improved. The correlation of efficiency with relative size of inactive zone at the exit of impeller is discussed as well as with average momentum fluxes in the scroll.

• 한국자동차공학회논문집
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• 제13권4호
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• pp.97-104
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• 2005

Vision-based lane sensing systems require accurate and robust sensing performance in lane detection. Besides, there exists trade-off between the computational burden and processor cost, which should be considered for implementing the systems in passenger cars. In this paper, a stereo vision-based lane detection system is developed with considering sensor configuration aspects. An inverse perspective mapping method is formulated based on the relative correspondence between the left and right cameras so that the 3-dimensional road geometry can be reconstructed in a robust manner. A new monitoring model for estimating the road geometry parameters is constructed to reduce the number of the measured signals. The selection of the sensor configuration and specifications is investigated by utilizing the characteristics of standard highways. Based on the sensor configurations, it is shown that appropriate sensing region on the camera image coordinate can be determined. The proposed system is implemented on a passenger car and verified experimentally.