자율 주행을 위한 3D Point Cloud Data 기반 물체 탐지 및 분류 기법에 관한 연구

학위논문 (박사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2017. 2. 서승우.A 3D LIDAR provides 3D surface information of objects with the highest position accuracy, among available sensors that can be utilized to develop perception algorithms for automated driving vehicles. In terms of automated driving, the accurate surface information gives the following benefits: 1) the accurate position information that is quite useful itself for collision avoidance is stably provided regardless of illumination condition, because the LIDAR is an active sensor. 2) the surface information can provide precise 3D shape-oriented features for object classification. Motivated by these characteristics, we propose three algorithms for a perception purpose of automated driving vehicles based on the 3D LIDAR in this dissertation. A very first procedure to utilize the 3D LIDAR as a perception sensor is segmentation that transform a stream of the LIDAR measurements into multiple point groups, where each point group indicate an individual object near the sensor. In chapter 2, a real-time and accurate segmentation is proposed. In particular, Gaussian Process regression is used to solve a problem called over-segmentation that increases False Positives by partitioning an object into multiple portions. The segmentation result can be utilized as input of another perception algorithm, such as object classification that is required for designing more human-likely driving strategies. For example, it is important to recognize pedestrians in urban driving environments because avoiding collisions with pedestrians are nearly a top priority. In chapter 3, we propose a pedestrian recognition algorithm based on a Deep Neural Network architecture that learns appearance variation. Another traffic participant that should be recognized with high-priority is a vehicle. Because various vehicle types of which appearances differ, such as a sedan, a bus, or a truck, are present on road, detection of the vehicles with similar performance regardless of the types is necessary. In chapter 4, we propose an algorithm that makes use of a common appearance of vehicles to solve the problem. To improve performance, a monocular camera is additionally employed, where the information from both sensors are integrated by a Dempster-Shafer Theory framework.Chapter 1 Introduction 1 1.1 Background and Motivations 1 1.2 Contributions and Outline of the Dissertation 3 1.2.1 Real-time and Accurate Segmentation of 3D Point Clouds based on Gaussian Process Regression 3 1.2.2 Pedestrian Recognition Based on Appearance Variation Learning 4 1.2.3 Vehicle Recognition using a Common Appearance Captured by a 3D LIDAR and a Monocular Camera 5 Chapter 2 Real-time and Accurate Segmentation of 3D Point Clouds based on Gaussian Process Regression 6 2.1 Introduction 6 2.2 Related Work 10 2.3 Framework overview 15 2.4 Clustering of Non-ground Points 16 2.4.1 Graph Construction 17 2.4.2 Clustering of Points on Vertical Surface 17 2.4.3 Cluster Extension 21 2.5 Accuracy Enhancement 24 2.5.1 Approach to Handling Over-segmentation 26 2.5.2 Handling Over-segmentation with GP Regression 27 2.5.3 Learning Hyperparameters 31 2.6 Experiments 32 2.6.1 Experiment Environment 32 2.6.2 Evaluation Metrics 33 2.6.3 Processing Time 36 2.6.4 Accuracy on Various Driving Environments 37 2.6.5 Impact on Tracking 46 2.7 Conclusion 48 Chapter 3 Pedestrian recognition based on appearance variation learning 50 3.1 Introduction 50 3.2 Related Work 53 3.3 Appearance Variation Learning 56 3.3.1 Primal Input Data for the Proposed Architecture 57 3.3.2 Learning Spatial Features from Appearance 57 3.3.3 Learning Appearance Variation 59 3.3.4 Classification 61 3.3.5 Data Augmentation 61 3.3.6 Implementation Detail 61 3.4 EXPERIMENTS 62 3.4.1 Experimental Environment 62 3.4.2 Experimental Results 65 3.5 CONCLUSIONS AND FUTURE WORKS 70 Chapter 4 Vehicle Recognition using a Common Appearance Captured by a 3D LIDAR and a Monocular Camera 72 4.1 Introduction 72 4.2 Related Work 75 4.3 Vehicle Recognition 77 4.3.1 Point Cloud Processing 78 4.3.2 Image Processing 80 4.3.3 Dempster-Shafer Theory (DST) for Information Fusion 82 4.4 Experiments 84 4.5 Conclusion 87 Chapter 5 Conclusion 89 Bibliography 91 국문초록 105Docto

Hepatitis B Virus Infection Rate among Koreans

To explore the overall infection state of Hepatitis B virus(HBV) in Korea during the 1980's, the standard valuesl weighted mean values) of infection ratelllt), the acute infection rate(AIR), and the chronic carrier ratelCCR) of HBV were estimated through summerizing the serological data from previous articles. The data used in this analysis include some cross sectional and a few follow-up studies, and were limited to those tested by the methods of radio immunoassay(RIA), reverse passive hemagglutiuation( RPHA), passive hemagglutination(PHA), or enzyme immunoassay(EIA) in order to maximize the validity. Using the sensitivity and specificity of each test method, we corrected the serological positivities from all data as if they were tested by RIA only. The age and sex specific IRs, AIRs, and CCRs of HBV were estimated, and the age adjusted rate for each sex was also estimated on the basis of the age structure of the 1985 population census. The IRs for men and women are 61.3% and 52.8%, the AIRs are 3.3% and 2.9%, and the CCRs are 4.7% and 3.3%, respectively

Analysis of research papers published in the Journal of the Korean Academy of Nursing-focused on research trends, intervention studies, and level of evidence in the research

The number of quantitative studies was greater than that of qualitative studies. There was a slight increase in the number of qualitative studies and studies including elderly populations, which reflects the recent population trend in Korea. More randomized controlled trials with a low risk of bias were needed to support more evidence-based nursing practice. Concerning the low rate of ethical consideration, stricter application of research ethics needs to be encouraged. Conclusion: The findings of this study suggest the recent trends in nursing research and the direction of nursing research and review in the Journal

Cigarette Smoking and Risk of Lung Cancer in Korean Men: The Seoul Male Cancer Cohort Study

Lung cancer is the leading cause of cancer deaths in Korea. The aim of this study was to estimate lung cancer risk of cigarette smoking in Korean men by a 10-yr follow-up prospective cohort study using the primary databases. The number of subjects was 14,272 men, who had full information of smoking habits among participants in the Seoul Male Cancer Cohort Study (SMCC). Total 125,053 person-years were calculated by determining the number of days from the start of follow-up, January 1, 1993, until the date of lung cancer diagnosis, death from another cause, or the end of follow-up, December 31, 2002, followed by converting the number of days to years. The information of outcome was obtained by the database of Korea Central Cancer Registry, Seoul Regional Cancer Registry, and Korea Statistical Office. The relative risk (RR) and its 95% confidence interval (CI) values of smoking were calculated using Cox proportional hazards regression stratified on potential confounders. During the follow-up periods, 78 cases of lung cancer occurred. The cigarette smoking is the major risk factor and increases the 4.18-fold risk of lung cancer in Korean men. In order to control lung cancer, intervention of quitting smoking is needed

Novel Swine-Origin Influenza A (H1N1) Viral Encephalitis

The World Health Organization declared that a new strain of novel swine-origin influenza A (H1N1) virus was responsible for the pandemic infection in June 2009. We report a case of encephalitis diagnosed as the H1N1 virus infection. We describe a 17-year-old patient who had a seizure attack, diagnosed with a H1N1 virus infection via real time reverse-transcriptase polymerase chain reaction (RT-PCR). The H1N1 virus infection can be causative of the encephalitis, as with other influenza virus infections. Careful monitoring is essential for reducing complications

Pacemaker Lead Endocarditis Caused by Achromobacter xylosoxidans

We report the case of a 35-yr-old patient who presented with high fever and chills. He had undergone a patch closure of the ventricular septal defect 18 yr before. One year later, a VVI pacemaker was implanted via the right subclavian vein because of complete heart block. Nine years after that, a new VVI pacemaker with another right ventricular electrode was inserted controlaterally and the old pacing lead was abandoned. Trans-thoracic and trans-esophageal echocardiogram identified the pacemaker lead in the right ventricle (RV) attaching hyperechoic materials and also a fluttering round hyperechoic mass with a stalk in the RV outflow tract. Cultures in blood and pus from pacemaker lead grew Achromobacter xylosoxidans. A diagnosis of pacemaker lead endocarditis due to Achromobacter xylosoxidans was made. In this regards, the best treatment is an immediate removal of the entire pacing system and antimicrobial therapy

Primary Cardiac Angiosarcoma Presenting With Cardiac Tamponade

Primary cardiac angiosarcoma is a very rare disease with a poor prognosis. We report a case of a patient with a primary cardiac angiosarcoma who presented with cardiac tamponade; the angiosarcoma was successfully resected surgically