• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2021.11a
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• pp.101-103
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• 2021

With the rapid increase in the quantity of goods transported worldwide, companies are now started to show great interest in unmanned automated warehouses along with related research and development due to the increase of warehouse efficiency and reduction warehouse manpower. In a number of small warehouses, shuttle rack-based layouts that can handle inventory flow flexibly. However, the shuttle rack-based logistics center does not operate in case of emergency situations (faults, power outages, etc.), which seriously affects the efficiency and inventory management of the entire logistics center. Accordingly, in shuttle rack-based logistics center, we have classified various shuttle passages and RTV passages by layout and have analyzed its characteristics and types, along with derived reliability for each layout. The loading rate was also derived differently according to the number of passages, and have compared and analyzed reliability and loading rate for each layout.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.141-148
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• 2003

This paper presents a rotating ann test for assessment of an underwater hybrid navigation system for a semi-autonomous underwater vehicle. The navigation system consists of an inertial measurement unit (IMU), an ultra-short baseline (USBL) acoustic navigation sensor and a doppler velocity log (DVL) accompanying a magnetic compass. The errors of inertial measurement units increase with time due to the bias errors of gyros and accelerometers. A navigational system model is derived to include the error model of the USBL acoustic navigation sensor and the scale effect and bias errors of the DVL, of which the state equation composed of the navigation states and sensor parameters is 25 in the order. The conventional extended Kalman filter was used to propagate the error covariance, update the measurement errors and correct the state equation when the measurements are available. The rotating ann tests are conducted in the Ocean Engineering Basin of KRISO, KORDI to generate circular motion in laboratory, where the USBL system was absent in the basin. The hybrid underwater navigation system shows good tracking performance against the circular planar motion. Additionally this paper checked the effects of the sampling ratio of the navigation system and the possibility of the dead reckoning with the DVL and the magnetic compass to estimate the position of the vehicle.

• Journal of Ocean Engineering and Technology
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• v.18 no.4 s.59
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• pp.33-39
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• 2004

This paper presents a hybrid underwater navigation system for unmanned underwater vehicles, using an additional range sonar, where the navigation system is based on inertial and Doppler velocity sensors. Conventional underwater navigation systems are generally based on an inertial measurement unit (IMU) and a Doppler velocity log (DVL), accompanying a magnetic compass and a depth sensor. Although the conventional navigation systems update the bias errors of inertial sensors and the scale effects of DVL, the estimated position slowly drifts as time passes. This paper proposes a measurement model that uses the range sonar to improve the performance of the IMU-DVL navigation system, for extended operation of underwater vehicles. The proposed navigation model includes the bias errors of IMU, the scale effects of VL, and the bias error of the range sonar. An extended Kalman filter was adopted to propagate the error covariance, to update the measurement errors, and to correct the state equation, when the external measurements are available. To illustrate the effectiveness of the hybrid navigation system, simulations were conducted with the 6-d.o.f. equations of motion of an AUV in lawn-mowing survey mode.

• Journal of Ocean Engineering and Technology
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• v.28 no.6
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• pp.566-573
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• 2014

This paper presents the results of an integrated navigation performance analysis for selecting the sensor of an unmanned underwater vehicle (UUV) using Monte Carlo numerical simulation. An inertial measurement unit (IMU) and Doppler velocity log (DVL) are considered to build the integrated navigation system. The position error and price of the sensor are selected as performance indices to evaluate the volunteer integrated navigation systems. Monte-Carlo simulation is introduced to analyze the circular error probability (CEP) and its variance. Simulation results provide the proper sensor combination for integrated navigation in relation to the performance and price.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.157-158
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• 2022

최근 자율운항선박, 무인선박 등 해사분야의 4차 산업혁명이 가속화되고 있으나 이에 대비한 해사안전분야 전문인력 양성체계는 없었다. 선장, 안전관리자, 선박소유자의 안전관련 책임 및 의무를 강화하고, 안전관리의 전문성 및 책임성 제고를 위해 선박안전관리사 자격제도가 신설되었다. 법률개정에 따라 안전관리자의 교육과정, 기존 안전관리자의 자격취득 교육 및 평가과정 등을 마련하기 위한 연구가 수행되고 있다. 이에 본 연구에서는 해사안전분야 전문인력 양성 지원을 위한 전문연구용역 진행 및 추진상황을 소개하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.406-407
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• 2022

자율운항선박, 무인선과 같이 전통적 선박 형태에 자율성이 부여되는 형태로의 발전과 함께 드론, 비행체 같은 비행 형태까지 포함하는 해상 모빌리티는 기존 통신 체계 대비 실시간성 향상 및 대용량 데이터 교환이 요구되는 새로운 해상 안전 운항 체계가 수반되어야 한다. 초고속해상무선통신망(LTE-Maritime) 송수신기를 장착한 국내 선박의 경우, LTE급의 통신 서비스를 연안 최대 100km까지 받을 수 있지만, 국제 항해를 하는 국적선과 외국적 선박을 포함하는 해상 모빌리티 안전 운항 체계 구축을 위해서는 VDES(VHF Data Exchange System)와 같은 국제협약에서 인정하고 해상이동서비스(Maritime Mobile Service)에 속하면서 기존보다 빠른 통신망의 보급이 필수적이다. 본 논문에서는 향후 해상 모빌리티 구현을 위해 필요한 해상무선통신망의 하나로 VDES의 필요성에 주목하여 그간의 개발 현황으로부터 향후 VDES 서비스 도입 및 활용방안에 관해 논한다.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.4_2
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• pp.943-951
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• 2024

This paper considers the simulation-based installation and operation safety analysis of installation and operation machinery of USBL as underwater equipment in operation environments. The simulation model of this mechanical system was developed using flexible multibody dynamics simulation technology. Operation and environmental conditions were applied using dynamic forces model considering ocean environments. The developed simulation model was used to evaluate operation safety through eigenvalue analysis, dynamic forces analysis, and structural analysis. As the analysis results, the operation safety was very low in extreme operation condition due to increase of dynamic loads by VIV effect. It was not a problem because safety factor had more than 2.0 in this case. However, the operation safety should be further strengthened because the USBL and LARS was installed and utilized in unmanned vessel with automatic controls. In order to improve safety by avoiding VIV frequency, we redesigned the USBL pole.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.256-265
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• 2021

Ground, sea and air mobility, such as vehicles, ships, and airplanes, are generally operated by people. Based on the innovative development of autonomous decision-making systems and artificial intelligence (AI) following the recent fourth industrial revolution, research and development on maritime autonomous surface ships (MASS) is been actively performed around the world. Before the realization of the commercialization of MASS in international maritime transport, it is urgent to clarify the characteristics of this ship and its international legal status. This paper aims to analyze the concern of whether a ship without crew members will eventually be operated as a fully unmanned ship or can be recognized as a ship under international law as the number of crew members is gradually reduced owing to the development stage of autonomous ships. Consequently, based on the United Nations Convention on the Law of the Sea (UNCLOS) and the regulations of the International Maritime Organization (IMO), it was found that MASS has the same international legal status as general ships. In addition this paper presents the working principles of enacting and revising the IMO Conventions and international legal measures necessary for the safe operation of MASS.

• Korean Journal of Remote Sensing
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• v.36 no.2_2
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• pp.379-399
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• 2020

The detection of illegal ship is one of the key factors in building a marine surveillance system. Effective marine surveillance requires the means for continuous monitoring over a wide area. In this study, the possibility of ship detection monitoring based on satellite SAR, HF radar, UAV and AIS integration was investigated. Considering the characteristics of time and spatial resolution for each platform, the ship monitoring scenario consisted of a regular surveillance system using HFR data and AIS data, and an event monitoring system using satellites and UAVs. The regular surveillance system still has limitations in detecting a small ship and accuracy due to the low spatial resolution of HF radar data. However, the event monitoring system using satellite SAR data effectively detects illegal ships using AIS data, and the ship speed and heading direction estimated from SAR images or ship tracking information using HF radar data can be used as the main information for the transition to UAV monitoring. For the validation of monitoring scenario, a comprehensive field experiment was conducted from June 25 to June 26, 2019, at the west side of Hongwon Port in Seocheon. KOMPSAT-5 SAR images, UAV data, HF radar data and AIS data were successfully collected and analyzed by applying each developed algorithm. The developed system will be the basis for the regular and event ship monitoring scenarios as well as the visualization of data and analysis results collected from multiple platforms.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.221-222
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• 2023

The purpose of this study is to analyze the applicability and limitations of SPOT robots in the construction industry. The SPOT robot, which is being introduced to construction sites for smart construction with the progress of the 4th industrial revolution, is shaped like a four-legged dog and is equipped with various sensors for data collection and autonomous driving. In this study, hardware and software were analyzed, such as the size of the SPOT robot, mobility on slopes and heights, operating environment, and software functions that can collect data with a sensor weighing up to 14 kg. In addition, while the SPOT robot operates in a construction environment, performance such as stability, accuracy, signal connection distance, and obstacle avoidance are evaluated, and the applicability and limitations of the SPOT robot in the construction industry are analyzed. Based on this analysis, the purpose of this study is to evaluate when and how SPOT robots can be effectively used at construction sites, identify limitations, and derive contributions and improvements for the construction industry.