• Proceedings of the Korea Information Processing Society Conference
• /
• 2008.11a
• /
• pp.417-421
• /
• 2008

아웃라이어 탐지는 일반적이지 않은 특징을 가진 데이터를 찾는 기법으로 데이터 마이닝 분야의 중요한 연구 중 하나다. 본 논문에서는 센서 네트워크를 이용한 응용분야에서 아웃라이어를 효과적으로 탐지하기 위한 인-네트워크 처리 기법을 제안한다. 비컨 교환을 통해 데이터 교환 비용을 줄이고, 슬라이딩 윈도우를 이용하여 센서 노드간 불필요한 데이터 수신(overhearing)을 줄인다. 실험 결과, TDMA 를 이용하여 모든 데이터를 기지국으로 전송하는 Naïve 기법에 비해 평균 86.92% ~ 133.67% 네트워크 수명이 연장되었다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.33 no.4
• /
• pp.259-266
• /
• 2015

Change detection using the heterogeneous data such as aerial images, aerial LiDAR (Light Detection And Ranging), and satellite images needs to be developed to efficiently monitor the complicating land use change. We approached this problem not relying on the intensity value of the geospatial image, but by using RECC(Relative Edge Cross Correlation) which is based on the edge information over the urban and suburban area. The experiment was carried out for the aerial LiDAR data with high-resolution Kompsat-2 and −3 images. We derived the optimal window size and threshold value for RECC-based change detection, and then we observed the overall change detection accuracy of 80% by comparing the results to the manually acquired reference data.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2002.05c
• /
• pp.469-473
• /
• 2002

고성능의 인터넷과 컴퓨터의 보급은 Online Game이 개발 될 수 있는 기반을 만들었다. 또한 게임에 관련된 프로나 채널이 생길 정도의 많은 관심은 Online 게임이 급성장을 이루는데 많이 도움을 주었다. 그러나 많은 Online 게임 사용자는 서버 접속률과 진행 속도 저하의 원인된다. 그래서 접속한 많은 Client를 효과적으로 다를 수 있도록 각 게임마다의 각 특성에 맞는 Game Server의 구현을 필요로 한다. 이 논문에서는 그것의 한 방법으로 여러 개의 그룹별로 게임을 하는데 효과적인 서버를 연결 리스트와 multi-thread를 이용하여 구현하였다. Client를 효과적으로 관리하기 위하여 각 데이터를 연결 리스트로 연결하고 multi-thread 사용하여 클라이언트의 요청을 처리하였다.

• Proceedings of the Korean Institute of Landscape Architecture Conference
• /
• 2022.10a
• /
• pp.118-119
• /
• 2022

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.33 no.6
• /
• pp.1099-1110
• /
• 2023

The recognition system of autonomous driving and robot navigation performs vision work such as object recognition, tracking, and lane detection after multi-sensor fusion to improve performance. Currently, research on a deep learning model based on the fusion of a camera and a lidar sensor is being actively conducted. However, deep learning models are vulnerable to adversarial attacks through modulation of input data. Attacks on the existing multi-sensor-based autonomous driving recognition system are focused on inducing obstacle detection by lowering the confidence score of the object recognition model.However, there is a limitation that an attack is possible only in the target model. In the case of attacks on the sensor fusion stage, errors in vision work after fusion can be cascaded, and this risk needs to be considered. In addition, an attack on LIDAR's point cloud data, which is difficult to judge visually, makes it difficult to determine whether it is an attack. In this study, image scaling-based camera-lidar We propose an attack method that reduces the accuracy of LCCNet, a fusion model (camera-LiDAR calibration model). The proposed method is to perform a scaling attack on the point of the input lidar. As a result of conducting an attack performance experiment by size with a scaling algorithm, an average of more than 77% of fusion errors were caused.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.20 no.1
• /
• pp.174-192
• /
• 2021

The LIDAR sensor, which provides higher cognitive performance than cameras and radar, is difficult to apply to ADAS or autonomous driving because of its high price. On the other hand, as the price is decreasing rapidly, expectations are rising to improve existing autonomous driving functions by taking advantage of the LIDAR sensor. In level 3 autonomous vehicles, when a dangerous situation in the cognitive module occurs due to a sensor defect or sensor limit, the driver must take control of the vehicle for manual driving. If the driver does not respond to the request, the system must automatically kick in and implement a minimum risk maneuver to maintain the risk within a tolerable level. In this study, based on this background, a LIDAR-based LKS MRM algorithm was developed for the case when the normal operation of LKS was not possible due to troubles in the cognitive system. From point cloud data collected by LIDAR, the algorithm generates the trajectory of the vehicle in front through object clustering and converts it to the target waypoints of its own. Hence, if the camera-based LKS is not operating normally, LIDAR-based path tracking control is performed as MRM. The HAZOP method was used to identify the risk sources in the LKS cognitive systems. B, and based on this, test scenarios were derived and used in the validation process by simulation. The simulation results indicated that the LIDAR-based LKS MRM algorithm of this study prevents lane departure in dangerous situations caused by various problems or difficulties in the LKS cognitive systems and could prevent possible traffic accidents.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2010.04a
• /
• pp.257-258
• /
• 2010

Recently data, which are obtained by the airborne laser scanner system have been utilized to rapidly obtain three-dimensional location coordinates for a large area. According to operation regulation, the distance between a GPS base station and a aircraft GPS is fixed within a radius of 30km. In this paper, we compare data obtained by GPS observation station operated in National Geographic Information Institute with those obtained by GPS base station for making a airborne laser survey.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.31 no.2
• /
• pp.111-119
• /
• 2013

It is essential and fundamental to extract boundary information of target object via massive three-dimensional point data acquired from laser scanner. Especially extracting boundary information of manmade features such as buildings is quite important because building is one of the major components consisting complex contemporary urban area, and has artificially defined shape. In this research, extended ${\chi}$-algorithm using geometry information of point data was proposed to extract boundary information of building from three-dimensional point data consisting building. The proposed algorithm begins with composing Delaunay triangulation process for given points and removes edges satisfying specific conditions process. Additionally, to make whole boundary extraction process efficient, we used Sweep-hull algorithm for constructing Delaunay triangulation. To verify the performance of the proposed extended ${\chi}$-algorithm, we compared the proposed algorithm with Encasing Polygon Generating Algorithm and ${\alpha}$-Shape Algorithm, which had been researched in the area of feature extraction. Further, the extracted boundary information from the proposed algorithm was analysed against manually digitized building boundary in order to test accuracy of the result of extracting boundary. The experimental results showed that extended ${\chi}$-algorithm proposed in this research proved to improve the speed of extracting boundary information compared to the existing algorithm with a higher accuracy for detecting boundary information.

• Journal of Korea Multimedia Society
• /
• v.8 no.2
• /
• pp.225-232
• /
• 2005

A PDA has limitation of storage space and inconvenience of Pen-based equipment to input. To solve these problems, this paper implemented that previous Speech Recognition provides using XML(extensile Markup Language) Web Service and PDA Client is possible to use speech command by request Speech Recognition Web Service. This system consists of Mobile Client and Speech Recognition Web Service Provider. The Mobile Client transmits user information and speech data to the Speech Recognition Web Service Provider using DIME(Direct Internet Message Encapsulation). The Speech Recognition Web Service Provider returns recognition results and user name only to an authorized Mobile Client. So We are able to use speech service without installing Speech Recognition or Speech DB in PDA.

• Journal of Korean Society for Geospatial Information Science
• /
• v.17 no.2
• /
• pp.11-17
• /
• 2009

Terrestrial LiDAR can measure high capacity 3D-topography coordinates and try to apply to various public works such as tunnel surveying, facility deformation surveying. This experiment is about how to calculate ground cutting volume because the stage of the earth work spend lots of money and time among civil engineering works. Surveying cutting area using Terrestrial LiDAR and then calculating cutting area in planned area comparing sectional plan before construction and planned section and LiDAR data. Also, the values of the calculating ground cutting volume by three different resolution LiDAR has are compared and analyzed.