• 한국해양공학회지
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• 제36권3호
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• pp.181-193
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• 2022

This study presents a mission management technique that is a key component of underwater docking system used to expand the operating range of autonomous underwater vehicle (AUV). We analyzed the docking scenario and AUV operating environment, defining the feasible initial area (FIA) level, event level, and global path (GP) command to improve the rate of docking success and AUV safety. Non-holonomic constraints, mounted sensor characteristic, AUV and mission state, and AUV behavior were considered. Using AUV and docking station, we conducted experiments on land and at sea. The first test was conducted on land to prevent loss and damage of the AUV and verify stability and interconnection with other algorithms; it performed well in normal and abnormal situations. Subsequently, we attempted to dock under the sea and verified its performance; it also worked well in a sea environment. In this study, we presented the mission management technique and showed its performance. We demonstrated AUV docking with this algorithm and verified that the rate of docking success was higher compared to those obtained in other studies.

• Ocean Systems Engineering
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• 제9권4호
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• pp.391-407
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• 2019

Tracking the location (position) of a surface or underwater marine vehicle is important as part of guidance and navigation. While the Global Positioning System (GPS) works well in an open sea environment but its use is limited whenever testing scaled-down models of such vehicles in the laboratory environment. This paper presents the design, development and implementation of a low energy ultrasonic augmented single beacon-based localization technique suitable for such requirements. The strategy consists of applying Extended Kalman Filter (EKF) to achieve location tracking from basic dynamic distance measurements of the moving model from a fixed beacon, while on-board motion sensor measures heading angle and velocity. Iterative application of the Extended Kalman Filter yields x and y co-ordinate positions of the moving model. Tests performed on a free-running ship model in a wave basin facility of dimension 30 m by 30 m by 3 m water depth validate the proposed model. The test results show quick convergence with an error of few centimeters in the estimated position of the ship model. The proposed technique has application in the real field scenario by replacing the ultrasonic sensor with industrial grade long range acoustic modem. As compared with the existing systems such as LBL, SBL, USBL and others localization techniques, the proposed technique can save deployment cost and also cut the cost on number of acoustic modems involved.

• 한국전자통신학회논문지
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• 제5권4호
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• pp.480-485
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• 2010

본 논문에서는 친환경 스마트가전 응용시스템을 위한 모바일 로봇 플랫폼인 Ecobot을 개발하였다. Ecobot은 Zigbee 네트워크로 홈 네트워크를 구성한 친환경 스마트 가전 응용시스템에서 쾌적 환경 감시 및 안내의 역할을 수행한다. 쾌적 환경을 위해 환경 감시 센서가 탑재되어 있으며, Zigbee 네트워크를 통해 스마트 가전기기와 연동하여 스마트 가전기기를 제어하여 쾌적 환경을 유지시킨다. 또한 URG-04LX 레이저 거리 센서를 이용하여 자율주행 및 충돌 회피를 통해 실내 환경을 감시하게 된다.

• 한국자동차공학회논문집
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• 제20권4호
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• pp.16-24
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• 2012

This paper proposes a method utilizing Differential Global Position System (DGPS) with Real-Time Kinematic (RTK) and pre-built Geo-graphic Information System (GIS) to detect lane departure of a vehicle. The position of a vehicle measured by DGPS with RTK has 18 cm-level accuracy. The preconditioned GIS data giving accurate position information of the traffic lanes is used to set up coordinate system and to enable fast calculation of the relative position of the vehicle within the traffic lanes. This relative position can be used for safe driving by preventing the vehicle from departing lane carelessly. The proposed system can be a key component in functions such as vehicle guidance, driver alert and assistance, and the smart highway that eventually enables autonomous driving supporting system. Experimental results show the ability of the system to meet the accuracy and robustness to detect lane departure of a vehicle at high speed.

• 한국자동차공학회논문집
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• 제16권6호
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• pp.134-140
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• 2008

Preceding vehicle detection is a crucial issue for driver assistance system as well as for autonomous vehicle guidance function and it has to be performed with high reliability to avoid any potential collision. The vision-based preceded vehicle detection systems are regarded promising for this purpose because they require little infrastructure on a highway. However, the feasibility of these systems in passenger car requires accurate and robust sensing performance. In this paper, an preceded vehicle detection system is developed using stereo vision sensors. This system utilizes feature matching, epipoplar constraint and feature aggregation in order to robustly detect the initial corresponding pairs. After the initial detection, the system executes the tracking algorithm for the preceded vehicles including a leading vehicle. Then, the position parameters of the preceded vehicles or leading vehicles can be obtained. The proposed preceded vehicle detection system is implemented on a passenger car and its performances is verified experimentally.

• 한국ITS학회 논문지
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• 제11권4호
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• pp.10-18
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• 2012

본 논문은 최근 지능형교통시스템에서 중요한 수단으로 간주되고 있는 차량 간 통신을 이용한 분산식 첨단 교통정보시스템을 개발하고자 한다. 또한 독립자동유고감지 기능을 통해서 제안된 첨단 교통정보시스템의 효과를 개선하고자 한다. 이상적인 통신 환경을 가정한 단순화된 교통네트워크에서 미시적 시뮬레이션 모델인 VISSIM을 통해 제안된 첨단 교통정보시스템을 구현하였으며 특히 비반복적으로 일어나는 교통상황(예를 들면, 교통사고)을 사용하여 모델의 효과를 관찰하였다. 결론적으로 본 연구에서는 차량 간 통신을 통한 첨단 교통정보시스템의 효율성을 확인함과 동시에 독립자동 유고감지 기능이 시스템의 성능을 향상시키는 것을 보여주고 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권11호
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• pp.4426-4442
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• 2020

Since scene segmentation is becoming a hot topic in the field of autonomous driving and medical image analysis, researchers are actively trying new methods to improve segmentation accuracy. At present, the main issues in image semantic segmentation are intra-class inconsistency and inter-class indistinction. From our analysis, the lack of global information as well as macroscopic discrimination on the object are the two main reasons. In this paper, we propose a Densely connected residual Attention network (DA-Res2Net) which consists of a dense residual network and channel attention guidance module to deal with these problems and improve the accuracy of image segmentation. Specifically, in order to make the extracted features equipped with stronger multi-scale characteristics, a densely connected residual network is proposed as a feature extractor. Furthermore, to improve the representativeness of each channel feature, we design a Channel-Attention-Guide module to make the model focusing on the high-level semantic features and low-level location features simultaneously. Experimental results show that the method achieves significant performance on various datasets. Compared to other state-of-the-art methods, the proposed method reaches the mean IOU accuracy of 83.2% on PASCAL VOC 2012 and 79.7% on Cityscapes dataset, respectively.

• 대한안전경영과학회지
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• 제23권1호
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• pp.39-48
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• 2021

In the past, measures for the reduction of industrial accidents has led the safety and health policy of construction sites by the guidance, supervision and the regulation according to 「Occupation Safety and Health Act」 handled by Ministry of Employment and Labor (MOEL). Nowadays companies realize that due to the factors such as diversification of employment types, outsourcing of hazardous work, new construction method and complicated types of construction, etc., there is a limit on safety management for construction sites as far as it is passively led by the governmental safety management policy and regulation. In this study, in order to practice the autonomous safety management escaping from the government-led safety management, improvement plans are proposed and applied by analyzing the basic cause of the all kinds of fall accidents that could possibly occur in the apartment construction sites and by verifying the hazardous factors and risks by fields.

• International journal of advanced smart convergence
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• 제11권3호
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• pp.119-131
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• 2022

The purpose of this study is to analyze the difference in the degree of self-determination between the criteria that general high school students consider important when selecting subjects (hereinafter referred to as 'importance') and the criteria that are actually applied when selecting subjects (hereinafter referred to as 'implementation'), based on the existing motivation type discrimination scale and subject selection criteria scale. As a result of analysis based on the data of a total of 786 high school students, the degree of self-determination was found to be different for all 34 questions and 8 factors in importance and implementation. In general, the questions and factors showed a simple structure with the motivation types and showed the lowest correlation with the motivations at both ends of the self-determination continuum. Among the factors that students consider important when selecting subjects and the factors that are actually applied, the 'SAT' factor showed the highest positive correlation with identification control. In addition, it was found that autonomous subject selection was more preferred than subject selection based on extrinsic motivation. These results are not only meaningful as the first study to analyze the degree of self-determination in the subject selection of high school students, but also can be used as useful data for customized subject selection guidance according to the degree of self-determination. The implications of this study and suggestions for follow-up studies were discussed.

• 의학교육논단
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• 제26권1호
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• pp.36-40
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• 2024

Chonnam National University Medical School has designed and implemented two career planning programs: a three-phase curriculum-based program and a longitudinal non-curricular program over the course of 6 academic years. The three phases of the curriculum-based career planning program are self-assessment, career exploration, and field experience. The non-curricular career counseling program operates through a faculty advisor system, with each faculty member guiding a group of students from each academic year, and students in each year forming a mentor-mentee relationship. The non-curricular career exploration program consists of a student research support program, an international practice program in basic and clinical medicine, and a specialty exploration fair. A survey conducted among 38 graduates (54.3%) working as interns at Chonnam National University Hospital revealed that graduates preferred autonomous elective subjects within the curriculum-based program. They also responded positively to the faculty advisor system, through which they maintained close relationships. A focus group interview with three interns indicated that subjects providing direct experience in fields of interest and courses that students could choose freely were helpful in career decisions. Through follow-up research, it is necessary to design and operate a systematic career planning program based on an analysis of the needs of graduates taking part in a residency training program after selecting a medical specialty.