• International Journal of Aeronautical and Space Sciences
• /
• 제14권4호
• /
• pp.369-378
• /
• 2013

This paper presents a vision/LiDAR integrated navigation system that provides accurate relative navigation performance on a general ground surface, in GNSS-denied environments. The considered ground surface during flight is approximated as a piecewise continuous model, with flat and slope surface profiles. In its implementation, the presented system consists of a strapdown IMU, and an aided sensor block, consisting of a vision sensor and a LiDAR on a stabilized gimbal platform. Thus, two-dimensional optical flow vectors from the vision sensor, and range information from LiDAR to ground are used to overcome the performance limit of the tactical grade inertial navigation solution without GNSS signal. In filter realization, the INS error model is employed, with measurement vectors containing two-dimensional velocity errors, and one differenced altitude in the navigation frame. In computing the altitude difference, the ground slope angle is estimated in a novel way, through two bisectional LiDAR signals, with a practical assumption representing a general ground profile. Finally, the overall integrated system is implemented, based on the extended Kalman filter framework, and the performance is demonstrated through a simulation study, with an aircraft flight trajectory scenario.

• 한국CDE학회논문집
• /
• 제13권4호
• /
• pp.265-272
• /
• 2008

The flow of technology is going to human-oriented direction, from the time when the computer was first invented, to now where new computing environment using mobile and global network are everywhere. On that technology flow, ubiquitous is being suggested as new paradigm of computing environment. Augmented Reality is one of ubiquitous technologies that provide the interactions between human and computer. By adding computer-generated information to real information and their interaction, user can get the improved and more knowledgeable information about real world. The purpose of this paper is to show the possibility of applying vision based augmented reality to maintenance of product system.

• 소성∙가공
• /
• 제25권4호
• /
• pp.242-247
• /
• 2016

CFD simulation with FlowVision^® is used to evaluate the capability of cooling channel in hot press forming dies. Two different types of cooling channels, dry drilled and pocket types are considered for comparison. Two different approaches for simulating cooling channel are considered. One is single-phase velocity calculation for coolant only and the other is multiphase thermal and velocity calculation for die, blank and coolant all together. Both approaches show better cooling performance in pocket type cooling channel. Also both approaches show their own effectiveness in designing cooling channel of hot press forming dies.

• 기술사
• /
• 제31권1호
• /
• pp.9-16
• /
• 1998

For the flow facing high1y informationized age, there is a flow from fixed communications connecting fixed places such as offices and homes to mobile communications connecting mobile objets such as automobiles, ships and aircraft. This flow has added to diversifying communications Including data and images. While the axed mode is diversifying information media by digitalization of communications network and computers, the mobile mode has brought higher sophistication of communication modes by a higher degree of electric wave utilization. The following descriptions outlines the mobile communication which is utilizing the electric wave phenomena. In sequence the following items are described: a brief history of mobile communications, the technical object and various kinds of services, propagation of electric wave signal.

• 기술사
• /
• 제31권2호
• /
• pp.65-72
• /
• 1998

For the flow facing highly informationized age, there Is a flow from fixed communications connecting fixed places such as offices and homes to mobile communications connecting mobile objets such as automobiles, ships and aircraft. This flow has added to diversifying communications including data and images. While the fixed mode Is diversifying information media by digitalization of communications network and computers, the mobile mode has brought higher sophistication of communication modes by a higher degree of electric wave utilization. The following descriptions outlines the mobile communication which Is utilizing the electric wave phenomena. In sequence the following items are described: a brief history of mobile communications, the technical object and various kinds of services, propagation of electric wave signal.

• 디지털융복합연구
• /
• 제16권11호
• /
• pp.383-392
• /
• 2018

본 연구는 보건계열 일부 대학생의 토익 학습몰입과 관련된 융복합적 요인들을 조사하였다. 설문조사는 2018년 5월 1일부터 2018년 5월 25일까지 J지역에 소재한 대학의 보건계열 토익학습반에서 임의로 선정된 대학생 255명에 대하여 무기명 자기기입식 설문지를 사용하였다. 위계적 다중회귀분석 결과, 자기효능감이 높을수록, 학업통제감이 높을수록, 학교적응유연성이 높을수록 토익 학습몰입이 높았으며 이들의 설명력은 43.4%이었다. 연구결과를 볼 때, 보건계열 대학생의 토익 학습몰입을 높이기 위해서는 자기효능감, 학업통제감 및 학교적응유연성을 높이는 노력이 필요하다. 이러한 결과는 보건계열 대학생의 토익 학습몰입을 높이는 토익학습 프로그램 개발 및 운영에 활용될 수 있다. 추후연구에서는 보건계열 대학생의 토익 학습몰입에 영향을 미치는 구조방정식 모형의 분석이 필요하다.

• Korean Circulation Journal
• /
• 제54권8호
• /
• pp.497-498
• /
• 2024

• Smart Structures and Systems
• /
• 제15권6호
• /
• pp.1583-1600
• /
• 2015

When natural disasters occur, including earthquakes, tsunamis, and debris flows, they are often accompanied by various types of damages such as the collapse of buildings, broken bridges and roads, and the destruction of natural scenery. Natural disaster detection and warning is an important issue which could help to reduce the incidence of serious damage to life and property as well as provide information for search and rescue afterwards. In this study, we propose a novel computer vision technique for debris flow detection which is feature-based that can be used to construct a debris flow event warning system. The landscape is composed of various elements, including trees, rocks, and buildings which are characterized by their features, shapes, positions, and colors. Unlike the traditional methods, our analysis relies on changes in the natural scenery which influence changes to the features. The "background module" and "monitoring module" procedures are designed and used to detect debris flows and construct an event warning system. The multi-criteria decision-making method used to construct an event warring system includes gradient information and the percentage of variation of the features. To prove the feasibility of the proposed method for detecting debris flows, some real cases of debris flows are analyzed. The natural environment is simulated and an event warning system is constructed to warn of debris flows. Debris flows are successfully detected using these two procedures, by analyzing the variation in the detected features and the matched feature. The feasibility of the event warning system is proven using the simulation method. Therefore, the feature based method is found to be useful for detecting debris flows and the event warning system is triggered when debris flows occur.

• 제어로봇시스템학회논문지
• /
• 제20권1호
• /
• pp.70-77
• /
• 2014

This paper proposes a novel localization algorithm based on ego-motion which used Lucas-Kanade Optical Flow and warping image obtained through fish-eye lenses mounted on the robots. The omnidirectional image sensor is a desirable sensor for real-time view-based recognition of a robot because the all information around the robot can be obtained simultaneously. The preprocessing (distortion correction, image merge, etc.) of the omnidirectional image which obtained by camera using reflect in mirror or by connection of multiple camera images is essential because it is difficult to obtain information from the original image. The core of the proposed algorithm may be summarized as follows: First, we capture instantaneous $360^{\circ}$ panoramic images around a robot through fish-eye lenses which are mounted in the bottom direction. Second, we extract motion vectors using Lucas-Kanade Optical Flow in preprocessed image. Third, we estimate the robot position and angle using ego-motion method which used direction of vector and vanishing point obtained by RANSAC. We confirmed the reliability of localization algorithm using ego-motion based on fisheye warping image through comparison between results (position and angle) of the experiment obtained using the proposed algorithm and results of the experiment measured from Global Vision Localization System.

• 한국전산구조공학회논문집
• /
• 제31권4호
• /
• pp.165-171
• /
• 2018

본 연구에서는 DVR 내부 공기유동을 직접 제어하여 CPU의 온도를 낮추기 위한 유동제어 구조물을 제안하였다. 제안된 구조물은 세 개의 얇은 판의 형태로 구성되었으며, DVR 내부의 공기 유동을 포괄적으로 제어하여 CPU의 효율적인 방열을 유도하고자 하였다. DOE와 RSM을 이용한 매개변수 연구기법을 통해 유동제어 구조물의 형상을 최적화하였으며, 해석에는 유한체적방법을 이용한 유체역학 분석 패키지인 FlowVision을 사용하였다. 실제 DVR 기기에서의 실험을 통해 해석 결과를 검증한 결과 CPU의 온도가 $16.1^{\circ}C$ 낮아짐을 확인하였다.