• Journal of computational fluids engineering
• /
• v.14 no.2
• /
• pp.1-8
• /
• 2009

The purposes of present work are to analyze the convective heat transfer with three-dimensional Reynolds-averaged Navier-Stokes analysis, and to optimize shape of the mixing vane taken tolerance into consideration by using the analysis results. Response surface method is employed as an optimization technique. The objective function is defined as a combination of heat transfer rate and inverse of pressure drop. Two bend angles of mixing vane are selected as design variables. Thermal-hydraulic performances have been discussed and optimum shape has been obtained as a function of weighting factor in the objective function. The results show that the optimized geometry improves the heat transfer performance far downstream of the mixing vane.

• Proceedings of the KSME Conference
• /
• 2001.06b
• /
• pp.313-318
• /
• 2001

A haptic hand controller operated by the user's hand can receive information on position and orientation of the hand and display force and moment generated in the virtual environment to the hand. This paper presents a design method for KU-HHC, 6 DOF Korea University-haptic hand controller, which allows separation of workspace from linkage mechanism in consideration of the efficient user operation. First, the 3 DOF mechanism in which all the actuators are mounted on the fixed base is developed by combining a 5-bar linkage and gimbal mechanism. Then, the 6 DOF HHC is designed by connecting the two 3 DOF devices through a handle. This paper presents the forward and inverse kinematics for this device and Jacobian analysis. Improvement of the kinematic characteristics using performance index is also discussed. The hand controller KU-HHC based on this design concept and kinematic analysis was manufactured and shows excellent performance.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2002.10a
• /
• pp.250-255
• /
• 2002

We developed a Off-Line Graphic Simulator which can simulate a robot model in 3D graphics space in Windows 98 version. 4 axes industrial robot was adopted as an objective model. Forward kinematics, inverse kinematics and robot dynamics modeling were included in the developed program. The interface between users and the off-line program system in the Windows 98's graphic user interface environment was also studied. The developing language is Microsoft Visual C++. Graphic libraries, OpenGL, by Silicon Graphics, Inc. were utilized for 3D graphics.

• Journal of IKEEE
• /
• v.19 no.2
• /
• pp.271-275
• /
• 2015

This paper proposes a unified HEVC $4{\times}4$ IDCT/IDST architecture for area reduction. In general, $4{\times}4$ IDCT and $4{\times}4$ IDST blocks are implemented separately, and they are connected with multiplexers. In the proposed arechitecture, these two blocks are unified, and internal hardware resources such as multipliers are shared. This reduces the chip area. The synthesized block in 0.18 um technology is 2,795 gates, and the gate count is reduced by 9.44% in comparison with conventional designs.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.36 no.2
• /
• pp.129-139
• /
• 1987

In this paper the programming language for Hero-1 robot is developed using Apple II micro computer. The language is composed of main monitor mode, editing mode, execution mode, and debugging mode. The main monitor mode is a main flow of the whole language system and controls starting and terminating procedures of operating the controller, and monitors the others. The editing mode has capability to make a user's maniqulation program. Trajectory planning algorithms(point-to-point motion and linear approximate motion)have been realized in the robot language, and in the case of point-to-point motion, inverse kinematics have been solved for the desired point.

• Journal of Korean Society for Quality Management
• /
• v.26 no.1
• /
• pp.74-87
• /
• 1998

This study considers optimal design of accelerated life tests under constant stress using that the first passage time to cross a critical boundary through amount of accumulated degradation has an inverse Gaussian distribution when the degradation process follows to a Brownian motion with positive drift of log linear function of stress. Optimum plans for Type I censoring are derived by minimizing the asymptotic variance of estimated quantiles at the use stress. Sensitivity analyses are also conducted to see how sensitive the optimality criterion is with respect to the uncertainties involved in the guessed values.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2003.05b
• /
• pp.14-18
• /
• 2003

This paper presents the pipeline architecture for the low and column address generator of 2D DCT/IDCT(Discrete Cosine Transform/Inverse Discrete Cosine Transform). For the real time process of image data, it is required that high speed operation and small size hardware In the proposed architecture, the area of hardware is reduced by using the DA(distributed arithmetic) method and applying the concepts of pipeline on the parallel architecture. As a results, the designed pipeline of the low and column address generator for 2D DCT/IDCT architecture is implemented with an efficiency and high speed compared as the non-pipeline architecture. And the operation speed is improved about 50％ up. The design for the proposed pipeline architecture of DCT/IDCT is coded using VHDL.

• Journal of the Korean Society of Industry Convergence
• /
• v.22 no.3
• /
• pp.325-335
• /
• 2019

In this paper, a novel adaptive gripper with underactuation is presented, which can change its configuration to parallel or power grip mode according to object shapes. Differently from the commercial adaptive gripper by RobotiQ, the proposed gripper includes an actual parallelogram inside a five-bar mechanism, which allows the free selection of actuator locations and can reduce actuation torques effectively. The forward and inverse kinematics for two grip modes and statics analysis have been analyzed. From the comparative design, the proposed gripper has about 20% smaller size, 3.7% larger stroke, and 30.5% smaller average actuation torque than the commercial one.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2022.07a
• /
• pp.527-528
• /
• 2022

빠르게 변하는 환경에 맞춰 평생 교육이 일반화되고 개인에게 요구되는 학습량은 많아지고 있으며 높아진 학습량에 맞게 학습 시간 단축과 효율적인 학습을 위한 학습 방법을 선택하는 것이 중요해지고 있다. 본 논문에서는 학습 정리를 위해 작성한 문서를 분석하여 해당 문서와 관련된 문서를 제안하고 본 문서와 엮어 학습을 위한 문서 묶음을 만들 수 있는 시스템을 제안한다. 문서의 유사도, 중요도를 구할 수 있는 TF-IDF를 이용하여 문서를 분석해 키워드를 추출한 다음 그와 관련된 문서를 제안하고 문서 묶음을 만들어 조회할 수 있도록 한다. 이 시스템은 학습 정리 시 관련 문서를 함께 볼 수 있도록 하고, 필요하다면 묶음으로 만들어 효과적인 학습을 위한 도구로 이용할 수 있다.

• Journal of the Korean Society for Precision Engineering
• /
• v.14 no.1
• /
• pp.69-77
• /
• 1997

본 논문은 금형의 마무리 연마 작업을 로봇을 이용하여 자동화하기 위한 오프라인 프로그래밍 시스템개발을 그 내용으로 하고있다. 3차원 자유곡면 형상을 갖는 금형을 연마하기 위한 로봇 작업 경로를 효율적으로 생성하기 위해서는 기존의 교시 방법이 아닌 CAD시스템과 연계된 시뮬레이션 방식의 자동 경로 생성 방법이 요구된다. 본 연구에서 개발된 금형 연마 작업을 위한 오프라인 프로그래밍 시스템은 연마 작업 시뮬레이션을 위한 기하학적 모델링 기능, 로봇의 작업 공간을 고려한 작업장 배치 기능, 연마 로봇의 효율적인 기구학 해, 3차원 그래픽 시뮬레이션, 3차원 물체간의 충돌 검사 기능 및 유기적인 관계형 데이타 베이스 기능 등으로 구성된다. 본 시스템의 시뮬레이션 결과를 로봇의 위치 보정 과정을 거쳐 로봇 작업 프로그램 으로 변환함으로써 최종적으로 실제 연마 작업이 가능한, 정확하고 안전한 로봇 프로그램을 생성하였다.