• 대한공간정보학회지
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• 제19권3호
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• pp.75-82
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• 2011

본 연구에서는 기존 위성항법시스템의 경우 고가의 장비보유, 통신장애에 따른 이용의 제한 등의 단점을 보완할 수 있는 광역보정위성항법시스템인 위성기반보정시스템(SBAS: Satellite Based Augmentation System)의 하나인 OmniSTAR의 개요, 고정해에의 수렴시간(convergence time)을 분석한 결과, 동적모드(Dynamic mode)에서 약 39분, 정적모드(Static mode)에서 약 28분 소요되는 것으로 나타났다. 본 연구의 성과는 높은 정확도를 요구하지 않는 위치기반서비스(LBS: Location Based Service) 분야, 모바일 측위분야, 공간정보산업분야에 활용될 수 있을 것으로 사료된다.

• Nuclear Engineering and Technology
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• 제27권5호
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• pp.661-669
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• 1995

원자력시설에서 점검 및 보수작업을 위하여 이동로보트 KAEROT을 개발하였다. 이동로보트의 주행장치는 소차륜들이 부착된 유성차륜의 형태로 구성되어 높은 안정성을 유지하며 계단을 포함한 많은 장애물의 승하강이 가능하도록 설계하였다 본 논문에서는 로보트의 원격조작을 용이하게 하기 위하여 이동로보트의 기구학적 해석을 통하여 역기구학 해를 구하였고, 자동 계단승월 알고리즘을 제안하였다. 제안된 알고리즘은 이동경로를 결정한 후 제안된 기준경로를 추종할 수 있도록 각 차륜의 각속도를 구하는 것이다. 제작 오차가 있는 실험실내 계단에 대하여 시뮬레이션 및 실험을 수행하였다. 제안된 알고리즘은 로보트 몸체의 경사각도를 낮게 유지시킬 수 있었고, 주행중 안정성을 높혀주었다.

• 한국CDE학회논문집
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• 제19권3호
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• pp.253-262
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• 2014

3D city model, which consisted of the 3D building models and their geospatial position and orientation, is becoming a valuable resource in virtual reality, navigation systems, civil engineering, etc. The purpose of this research is to propose the new framework to generate the 3D city model that satisfies visual and physical requirements in ground oriented simulation system. At the same time, the framework should meet the demand of the automatic creation and cost-effectiveness, which facilitates the usability of the proposed approach. To do that, I suggest the framework that leverages the mobile mapping system which automatically gathers high resolution images and supplement sensor information like position and direction of the image. And to resolve the problem from the sensor noise and a large number of the occlusions, the fusion of digital map data will be used. This paper describes the overall framework with major process and the recommended or demanded techniques for each processing step.

• International Journal of Control, Automation, and Systems
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• 제5권3호
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• pp.251-268
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• 2007

A Gaussian sum filter (GSF) is proposed in this paper on simultaneous localization and mapping (SLAM) for mobile robot navigation. In particular, the SLAM problem is tackled here for cases when only bearing measurements are available. Within the stochastic mapping framework using an extended Kalman filter (EKF), a Gaussian probability density function (pdf) is assumed to describe the range-and-bearing sensor noise. In the case of a bearing-only sensor, a sum of weighted Gaussians is used to represent the non-Gaussian robot-landmark range uncertainty, resulting in a bank of EKFs for estimation of the robot and landmark locations. In our approach, the Gaussian parameters are designed on the basis of minimizing the representation error. The computational complexity of the GSF is reduced by applying the sequential probability ratio test (SPRT) to remove under-performing EKFs. Extensive experimental results are included to demonstrate the effectiveness and efficiency of the proposed techniques.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2002년도 추계학술대회 및 정기총회
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• pp.239-242
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• 2002

점차 많은 형태의 가정용 로봇이 개발되고 있으며 일부 제품화되어 출시되고 있다. 이러한 가정용 로봇을 원격지에서 제어하고자 할 때 대부분이 인터넷이나 무선을 이용한 원격제어 또는 실시간 모니터링을 통해 제어하여 그 상황을 시뮬레이션으로 구현하고 있다. 그러나 제어대상이 극히 제한적인 수의 이동로봇인데 반해 다수의 가족 구성원인 제어조작자가 중복적으로 청소로봇과 같은 이동로봇을 제어하고자 접근을 시도했을 때 이동로봇에 다중적인 업무가 주어지게 될 수 도 있다. 이에 Database 를 이용하여 수행 업무의 우선순위와 제어조작자의 권한의 우선순위를 지정한 명령어를 Database 내에 구성하여 간접적으로 전송하여 제어하고자 한다. 그리고 제어를 통한 동작 시 실제 이동로봇의 속도와 방향 제어를 위해 퍼지 및 신경망을 이용한 지능제어를 구성하여 제어의 효율성을 극대화 하고자 한다.

• 융합신호처리학회논문지
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• 제1권2호
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• pp.160-168
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• 2000

본 논문은 FLC(Fuzzy Logic Control)를 이용한 원격제어 이동로봇이 다수 경유점을 보다 효율적으로 주행하는 방법을 연구하였다. 제작된 원격 제어 이동로봇은 전진, 후진, 좌회전, 우회전의 이동 명령을 한 가지씩 수행한 후 정지한다. 이러한 주행형태의 단점을 보완하기 위해 본 논문은 센서를 이용하여 얻어진 지형정보를 바탕으로 목적지까지 경유점 수를 줄이고, 경유점 간의 이동을 최적한 경로로 주행하도록 하였다. 그리고, 장애물 출현 시 회피할 수 있는 FLC 알고리즘을 개발하였다. 그리고, 이러한 주행 알고리즘을 시뮬레이션을 통해 확인하였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.423-427
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• 2002

Contrary to the traditional text-based information, 4S(GIS,GNSS,SIIS,ITS) information can contribute to the citizen's welfare in upcoming era. Recently, GSIS(Geo-Spatial Information System) has been applied and stressed out in various fields. As analyzed the data from GSIS arena, the position information of objects and targets is crucial and critical. Therefore, several methods of getting and knowing position are proposed and developed. From this perspective, Position collection and processing are the heart of 4S technology. We develop 4S-Van that enables real-time acquisition of position and attribute information and accurate image data in remote site. In this study, the configuration of 4S-Van equipped with GPS, INS, CCD and eye-safe laser scanner is shown and the merits of DGPS/INS integration approach for geo-referencing is briefly discussed. The algorithm of DGPS/INS integration fur determination of six parameters of motion is eccential in the 4S-Van to avoid or simplify the complicated computation such as photogrammetric triangulation. 4S-Van has the application of Laser-Mobile Mapping System for three-dimensional data acquisition that merges the texture information from CCD camera. The technique is also applied in the fields of virtual reality, car navigation, computer games, planning and management, city transportation, mobile communication, etc.

• 대한원격탐사학회지
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• 제19권1호
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• pp.91-97
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• 2003

The design of Graphic Information System(GIS) in various applications is suffering from the difficulty of data acquisition, which is labor-intensive and time consuming. In order to provide the spatial data rapidly and accurately, 4S-Van, a prototype mobile mapping system, has been developed. The 4S-Van consists of 1)Global Positioning System(GPS), Inertial Navigation System(INS) for estimating the geographic position and attitude of the moving van, i.e.,(x, y, z) and the direction of the Van, 2) Charge Coupled Device(CCD) camera and laser scanner for capturing images and for measuring depth from geographic objects, and 3) External Synchronization Device(ESD) and industrial PC for synchronizing data from GPS/INS/CCD camera and for storing the data. In this paper, we present the design and implementation of the proto-Dpe 4S-Van system for spatial data acquisition for various GIS applications.

• 한국측량학회지
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• 제37권5호
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• pp.331-341
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• 2019

With the popularity of sensor-rich environments, smartphones have become one of the major platforms for obtaining and sharing information. Since it is difficult to utilize GNSS (Global Navigation Satellite System) inside the area with many buildings, the localization of smartphone in this case is considered as a challenging task. To resolve problem of localization using smartphone a four step image-based localization method and procedure is proposed. To improve the localization accuracy of smartphone datasets, MMS (Mobile Mapping System) and Google Street View were utilized. In our approach first, the searching for candidate matching image is performed by the query image of smartphone's using GNSS observation. Second, the SURF (Speed-Up Robust Features) image matching between the smartphone image and reference dataset is done and the wrong matching points are eliminated. Third, the geometric transformation is performed using the matching points with 2D affine transformation. Finally, the smartphone location and attitude estimation are done by PnP (Perspective-n-Point) algorithm. The location of smartphone GNSS observation is improved from the original 10.204m to a mean error of 3.575m. The attitude estimation is lower than 25 degrees from the 92.4% of the adjsuted images with an average of 5.1973 degrees.

• 로봇학회논문지
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• 제14권2호
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• pp.87-93
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• 2019

This paper presents a 6-DOF relocalization using a 3D laser scanner and a monocular camera. A relocalization problem in robotics is to estimate pose of sensor when a robot revisits the area. A deep convolutional neural network (CNN) is designed to regress 6-DOF sensor pose and trained using both RGB image and 3D point cloud information in end-to-end manner. We generate the new input that consists of RGB and range information. After training step, the relocalization system results in the pose of the sensor corresponding to each input when a new input is received. However, most of cases, mobile robot navigation system has successive sensor measurements. In order to improve the localization performance, the output of CNN is used for measurements of the particle filter that smooth the trajectory. We evaluate our relocalization method on real world datasets using a mobile robot platform.